drivers/gpu/drm/display/drm_dp_mst_topology.c

   1 /*
   2  * Copyright © 2014 Red Hat
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and its
   5  * documentation for any purpose is hereby granted without fee, provided that
   6  * the above copyright notice appear in all copies and that both that copyright
   7  * notice and this permission notice appear in supporting documentation, and
   8  * that the name of the copyright holders not be used in advertising or
   9  * publicity pertaining to distribution of the software without specific,
  10  * written prior permission.  The copyright holders make no representations
  11  * about the suitability of this software for any purpose.  It is provided "as
  12  * is" without express or implied warranty.
  13  *
  14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  20  * OF THIS SOFTWARE.
  21  */
  22
  23 #include <linux/bitfield.h>
  24 #include <linux/delay.h>
  25 #include <linux/errno.h>
  26 #include <linux/i2c.h>
  27 #include <linux/init.h>
  28 #include <linux/kernel.h>
  29 #include <linux/random.h>
  30 #include <linux/sched.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/iopoll.h>
  33
  34 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
  35 #include <linux/stacktrace.h>
  36 #include <linux/sort.h>
  37 #include <linux/timekeeping.h>
  38 #include <linux/math64.h>
  39 #endif
  40
  41 #include <drm/display/drm_dp_mst_helper.h>
  42 #include <drm/drm_atomic.h>
  43 #include <drm/drm_atomic_helper.h>
  44 #include <drm/drm_drv.h>
  45 #include <drm/drm_edid.h>
  46 #include <drm/drm_print.h>
  47 #include <drm/drm_probe_helper.h>
  48
  49 #include "drm_dp_helper_internal.h"
  50 #include "drm_dp_mst_topology_internal.h"
  51
  52 /**
  53  * DOC: dp mst helper
  54  *
  55  * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
  56  * protocol. The helpers contain a topology manager and bandwidth manager.
  57  * The helpers encapsulate the sending and received of sideband msgs.
  58  */
  59 struct drm_dp_pending_up_req {
  60         struct drm_dp_sideband_msg_hdr hdr;
  61         struct drm_dp_sideband_msg_req_body msg;
  62         struct list_head next;
  63 };
  64
  65 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
  66                                   char *buf);
  67
  68 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
  69
  70 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
  71                                      int id, u8 start_slot, u8 num_slots);
  72
  73 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
  74                                  struct drm_dp_mst_port *port,
  75                                  int offset, int size, u8 *bytes);
  76 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
  77                                   struct drm_dp_mst_port *port,
  78                                   int offset, int size, u8 *bytes);
  79
  80 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
  81                                     struct drm_dp_mst_branch *mstb);
  82
  83 static void
  84 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
  85                                    struct drm_dp_mst_branch *mstb);
  86
  87 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
  88                                            struct drm_dp_mst_branch *mstb,
  89                                            struct drm_dp_mst_port *port);
  90 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
  91                                  u8 *guid);
  92
  93 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
  94 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
  95 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
  96
  97 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
  98                                                  struct drm_dp_mst_branch *branch);
  99
 100 #define DBG_PREFIX "[dp_mst]"
 101
 102 #define DP_STR(x) [DP_ ## x] = #x
 103
 104 static const char *drm_dp_mst_req_type_str(u8 req_type)
 105 {
 106         static const char * const req_type_str[] = {
 107                 DP_STR(GET_MSG_TRANSACTION_VERSION),
 108                 DP_STR(LINK_ADDRESS),
 109                 DP_STR(CONNECTION_STATUS_NOTIFY),
 110                 DP_STR(ENUM_PATH_RESOURCES),
 111                 DP_STR(ALLOCATE_PAYLOAD),
 112                 DP_STR(QUERY_PAYLOAD),
 113                 DP_STR(RESOURCE_STATUS_NOTIFY),
 114                 DP_STR(CLEAR_PAYLOAD_ID_TABLE),
 115                 DP_STR(REMOTE_DPCD_READ),
 116                 DP_STR(REMOTE_DPCD_WRITE),
 117                 DP_STR(REMOTE_I2C_READ),
 118                 DP_STR(REMOTE_I2C_WRITE),
 119                 DP_STR(POWER_UP_PHY),
 120                 DP_STR(POWER_DOWN_PHY),
 121                 DP_STR(SINK_EVENT_NOTIFY),
 122                 DP_STR(QUERY_STREAM_ENC_STATUS),
 123         };
 124
 125         if (req_type >= ARRAY_SIZE(req_type_str) ||
 126             !req_type_str[req_type])
 127                 return "unknown";
 128
 129         return req_type_str[req_type];
 130 }
 131
 132 #undef DP_STR
 133 #define DP_STR(x) [DP_NAK_ ## x] = #x
 134
 135 static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
 136 {
 137         static const char * const nak_reason_str[] = {
 138                 DP_STR(WRITE_FAILURE),
 139                 DP_STR(INVALID_READ),
 140                 DP_STR(CRC_FAILURE),
 141                 DP_STR(BAD_PARAM),
 142                 DP_STR(DEFER),
 143                 DP_STR(LINK_FAILURE),
 144                 DP_STR(NO_RESOURCES),
 145                 DP_STR(DPCD_FAIL),
 146                 DP_STR(I2C_NAK),
 147                 DP_STR(ALLOCATE_FAIL),
 148         };
 149
 150         if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
 151             !nak_reason_str[nak_reason])
 152                 return "unknown";
 153
 154         return nak_reason_str[nak_reason];
 155 }
 156
 157 #undef DP_STR
 158 #define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
 159
 160 static const char *drm_dp_mst_sideband_tx_state_str(int state)
 161 {
 162         static const char * const sideband_reason_str[] = {
 163                 DP_STR(QUEUED),
 164                 DP_STR(START_SEND),
 165                 DP_STR(SENT),
 166                 DP_STR(RX),
 167                 DP_STR(TIMEOUT),
 168         };
 169
 170         if (state >= ARRAY_SIZE(sideband_reason_str) ||
 171             !sideband_reason_str[state])
 172                 return "unknown";
 173
 174         return sideband_reason_str[state];
 175 }
 176
 177 static int
 178 drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
 179 {
 180         int i;
 181         u8 unpacked_rad[16];
 182
 183         for (i = 0; i < lct; i++) {
 184                 if (i % 2)
 185                         unpacked_rad[i] = rad[i / 2] >> 4;
 186                 else
 187                         unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
 188         }
 189
 190         /* TODO: Eventually add something to printk so we can format the rad
 191          * like this: 1.2.3
 192          */
 193         return snprintf(out, len, "%*phC", lct, unpacked_rad);
 194 }
 195
 196 /* sideband msg handling */
 197 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
 198 {
 199         u8 bitmask = 0x80;
 200         u8 bitshift = 7;
 201         u8 array_index = 0;
 202         int number_of_bits = num_nibbles * 4;
 203         u8 remainder = 0;
 204
 205         while (number_of_bits != 0) {
 206                 number_of_bits--;
 207                 remainder <<= 1;
 208                 remainder |= (data[array_index] & bitmask) >> bitshift;
 209                 bitmask >>= 1;
 210                 bitshift--;
 211                 if (bitmask == 0) {
 212                         bitmask = 0x80;
 213                         bitshift = 7;
 214                         array_index++;
 215                 }
 216                 if ((remainder & 0x10) == 0x10)
 217                         remainder ^= 0x13;
 218         }
 219
 220         number_of_bits = 4;
 221         while (number_of_bits != 0) {
 222                 number_of_bits--;
 223                 remainder <<= 1;
 224                 if ((remainder & 0x10) != 0)
 225                         remainder ^= 0x13;
 226         }
 227
 228         return remainder;
 229 }
 230
 231 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
 232 {
 233         u8 bitmask = 0x80;
 234         u8 bitshift = 7;
 235         u8 array_index = 0;
 236         int number_of_bits = number_of_bytes * 8;
 237         u16 remainder = 0;
 238
 239         while (number_of_bits != 0) {
 240                 number_of_bits--;
 241                 remainder <<= 1;
 242                 remainder |= (data[array_index] & bitmask) >> bitshift;
 243                 bitmask >>= 1;
 244                 bitshift--;
 245                 if (bitmask == 0) {
 246                         bitmask = 0x80;
 247                         bitshift = 7;
 248                         array_index++;
 249                 }
 250                 if ((remainder & 0x100) == 0x100)
 251                         remainder ^= 0xd5;
 252         }
 253
 254         number_of_bits = 8;
 255         while (number_of_bits != 0) {
 256                 number_of_bits--;
 257                 remainder <<= 1;
 258                 if ((remainder & 0x100) != 0)
 259                         remainder ^= 0xd5;
 260         }
 261
 262         return remainder & 0xff;
 263 }
 264 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
 265 {
 266         u8 size = 3;
 267
 268         size += (hdr->lct / 2);
 269         return size;
 270 }
 271
 272 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 273                                            u8 *buf, int *len)
 274 {
 275         int idx = 0;
 276         int i;
 277         u8 crc4;
 278
 279         buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 280         for (i = 0; i < (hdr->lct / 2); i++)
 281                 buf[idx++] = hdr->rad[i];
 282         buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 283                 (hdr->msg_len & 0x3f);
 284         buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 285
 286         crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 287         buf[idx - 1] |= (crc4 & 0xf);
 288
 289         *len = idx;
 290 }
 291
 292 static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,
 293                                            struct drm_dp_sideband_msg_hdr *hdr,
 294                                            u8 *buf, int buflen, u8 *hdrlen)
 295 {
 296         u8 crc4;
 297         u8 len;
 298         int i;
 299         u8 idx;
 300
 301         if (buf[0] == 0)
 302                 return false;
 303         len = 3;
 304         len += ((buf[0] & 0xf0) >> 4) / 2;
 305         if (len > buflen)
 306                 return false;
 307         crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 308
 309         if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 310                 drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 311                 return false;
 312         }
 313
 314         hdr->lct = (buf[0] & 0xf0) >> 4;
 315         hdr->lcr = (buf[0] & 0xf);
 316         idx = 1;
 317         for (i = 0; i < (hdr->lct / 2); i++)
 318                 hdr->rad[i] = buf[idx++];
 319         hdr->broadcast = (buf[idx] >> 7) & 0x1;
 320         hdr->path_msg = (buf[idx] >> 6) & 0x1;
 321         hdr->msg_len = buf[idx] & 0x3f;
 322         idx++;
 323         hdr->somt = (buf[idx] >> 7) & 0x1;
 324         hdr->eomt = (buf[idx] >> 6) & 0x1;
 325         hdr->seqno = (buf[idx] >> 4) & 0x1;
 326         idx++;
 327         *hdrlen = idx;
 328         return true;
 329 }
 330
 331 void
 332 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
 333                            struct drm_dp_sideband_msg_tx *raw)
 334 {
 335         int idx = 0;
 336         int i;
 337         u8 *buf = raw->msg;
 338
 339         buf[idx++] = req->req_type & 0x7f;
 340
 341         switch (req->req_type) {
 342         case DP_ENUM_PATH_RESOURCES:
 343         case DP_POWER_DOWN_PHY:
 344         case DP_POWER_UP_PHY:
 345                 buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 346                 idx++;
 347                 break;
 348         case DP_ALLOCATE_PAYLOAD:
 349                 buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 350                         (req->u.allocate_payload.number_sdp_streams & 0xf);
 351                 idx++;
 352                 buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 353                 idx++;
 354                 buf[idx] = (req->u.allocate_payload.pbn >> 8);
 355                 idx++;
 356                 buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 357                 idx++;
 358                 for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 359                         buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 360                                 (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 361                         idx++;
 362                 }
 363                 if (req->u.allocate_payload.number_sdp_streams & 1) {
 364                         i = req->u.allocate_payload.number_sdp_streams - 1;
 365                         buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 366                         idx++;
 367                 }
 368                 break;
 369         case DP_QUERY_PAYLOAD:
 370                 buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 371                 idx++;
 372                 buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 373                 idx++;
 374                 break;
 375         case DP_REMOTE_DPCD_READ:
 376                 buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 377                 buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 378                 idx++;
 379                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 380                 idx++;
 381                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 382                 idx++;
 383                 buf[idx] = (req->u.dpcd_read.num_bytes);
 384                 idx++;
 385                 break;
 386
 387         case DP_REMOTE_DPCD_WRITE:
 388                 buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 389                 buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 390                 idx++;
 391                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 392                 idx++;
 393                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 394                 idx++;
 395                 buf[idx] = (req->u.dpcd_write.num_bytes);
 396                 idx++;
 397                 memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 398                 idx += req->u.dpcd_write.num_bytes;
 399                 break;
 400         case DP_REMOTE_I2C_READ:
 401                 buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 402                 buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 403                 idx++;
 404                 for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 405                         buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 406                         idx++;
 407                         buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 408                         idx++;
 409                         memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 410                         idx += req->u.i2c_read.transactions[i].num_bytes;
 411
 412                         buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
 413                         buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 414                         idx++;
 415                 }
 416                 buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 417                 idx++;
 418                 buf[idx] = (req->u.i2c_read.num_bytes_read);
 419                 idx++;
 420                 break;
 421
 422         case DP_REMOTE_I2C_WRITE:
 423                 buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 424                 idx++;
 425                 buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 426                 idx++;
 427                 buf[idx] = (req->u.i2c_write.num_bytes);
 428                 idx++;
 429                 memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 430                 idx += req->u.i2c_write.num_bytes;
 431                 break;
 432         case DP_QUERY_STREAM_ENC_STATUS: {
 433                 const struct drm_dp_query_stream_enc_status *msg;
 434
 435                 msg = &req->u.enc_status;
 436                 buf[idx] = msg->stream_id;
 437                 idx++;
 438                 memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
 439                 idx += sizeof(msg->client_id);
 440                 buf[idx] = 0;
 441                 buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
 442                 buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
 443                 buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
 444                 buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
 445                 idx++;
 446                 }
 447                 break;
 448         }
 449         raw->cur_len = idx;
 450 }
 451 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
 452
 453 /* Decode a sideband request we've encoded, mainly used for debugging */
 454 int
 455 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
 456                            struct drm_dp_sideband_msg_req_body *req)
 457 {
 458         const u8 *buf = raw->msg;
 459         int i, idx = 0;
 460
 461         req->req_type = buf[idx++] & 0x7f;
 462         switch (req->req_type) {
 463         case DP_ENUM_PATH_RESOURCES:
 464         case DP_POWER_DOWN_PHY:
 465         case DP_POWER_UP_PHY:
 466                 req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
 467                 break;
 468         case DP_ALLOCATE_PAYLOAD:
 469                 {
 470                         struct drm_dp_allocate_payload *a =
 471                                 &req->u.allocate_payload;
 472
 473                         a->number_sdp_streams = buf[idx] & 0xf;
 474                         a->port_number = (buf[idx] >> 4) & 0xf;
 475
 476                         WARN_ON(buf[++idx] & 0x80);
 477                         a->vcpi = buf[idx] & 0x7f;
 478
 479                         a->pbn = buf[++idx] << 8;
 480                         a->pbn |= buf[++idx];
 481
 482                         idx++;
 483                         for (i = 0; i < a->number_sdp_streams; i++) {
 484                                 a->sdp_stream_sink[i] =
 485                                         (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
 486                         }
 487                 }
 488                 break;
 489         case DP_QUERY_PAYLOAD:
 490                 req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
 491                 WARN_ON(buf[++idx] & 0x80);
 492                 req->u.query_payload.vcpi = buf[idx] & 0x7f;
 493                 break;
 494         case DP_REMOTE_DPCD_READ:
 495                 {
 496                         struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
 497
 498                         r->port_number = (buf[idx] >> 4) & 0xf;
 499
 500                         r->dpcd_address = (buf[idx] << 16) & 0xf0000;
 501                         r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 502                         r->dpcd_address |= buf[++idx] & 0xff;
 503
 504                         r->num_bytes = buf[++idx];
 505                 }
 506                 break;
 507         case DP_REMOTE_DPCD_WRITE:
 508                 {
 509                         struct drm_dp_remote_dpcd_write *w =
 510                                 &req->u.dpcd_write;
 511
 512                         w->port_number = (buf[idx] >> 4) & 0xf;
 513
 514                         w->dpcd_address = (buf[idx] << 16) & 0xf0000;
 515                         w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 516                         w->dpcd_address |= buf[++idx] & 0xff;
 517
 518                         w->num_bytes = buf[++idx];
 519
 520                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 521                                            GFP_KERNEL);
 522                         if (!w->bytes)
 523                                 return -ENOMEM;
 524                 }
 525                 break;
 526         case DP_REMOTE_I2C_READ:
 527                 {
 528                         struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
 529                         struct drm_dp_remote_i2c_read_tx *tx;
 530                         bool failed = false;
 531
 532                         r->num_transactions = buf[idx] & 0x3;
 533                         r->port_number = (buf[idx] >> 4) & 0xf;
 534                         for (i = 0; i < r->num_transactions; i++) {
 535                                 tx = &r->transactions[i];
 536
 537                                 tx->i2c_dev_id = buf[++idx] & 0x7f;
 538                                 tx->num_bytes = buf[++idx];
 539                                 tx->bytes = kmemdup(&buf[++idx],
 540                                                     tx->num_bytes,
 541                                                     GFP_KERNEL);
 542                                 if (!tx->bytes) {
 543                                         failed = true;
 544                                         break;
 545                                 }
 546                                 idx += tx->num_bytes;
 547                                 tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
 548                                 tx->i2c_transaction_delay = buf[idx] & 0xf;
 549                         }
 550
 551                         if (failed) {
 552                                 for (i = 0; i < r->num_transactions; i++) {
 553                                         tx = &r->transactions[i];
 554                                         kfree(tx->bytes);
 555                                 }
 556                                 return -ENOMEM;
 557                         }
 558
 559                         r->read_i2c_device_id = buf[++idx] & 0x7f;
 560                         r->num_bytes_read = buf[++idx];
 561                 }
 562                 break;
 563         case DP_REMOTE_I2C_WRITE:
 564                 {
 565                         struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
 566
 567                         w->port_number = (buf[idx] >> 4) & 0xf;
 568                         w->write_i2c_device_id = buf[++idx] & 0x7f;
 569                         w->num_bytes = buf[++idx];
 570                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 571                                            GFP_KERNEL);
 572                         if (!w->bytes)
 573                                 return -ENOMEM;
 574                 }
 575                 break;
 576         case DP_QUERY_STREAM_ENC_STATUS:
 577                 req->u.enc_status.stream_id = buf[idx++];
 578                 for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
 579                         req->u.enc_status.client_id[i] = buf[idx++];
 580
 581                 req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
 582                                                            buf[idx]);
 583                 req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
 584                                                                  buf[idx]);
 585                 req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
 586                                                               buf[idx]);
 587                 req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
 588                                                                     buf[idx]);
 589                 break;
 590         }
 591
 592         return 0;
 593 }
 594 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
 595
 596 void
 597 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
 598                                   int indent, struct drm_printer *printer)
 599 {
 600         int i;
 601
 602 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
 603         if (req->req_type == DP_LINK_ADDRESS) {
 604                 /* No contents to print */
 605                 P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
 606                 return;
 607         }
 608
 609         P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
 610         indent++;
 611
 612         switch (req->req_type) {
 613         case DP_ENUM_PATH_RESOURCES:
 614         case DP_POWER_DOWN_PHY:
 615         case DP_POWER_UP_PHY:
 616                 P("port=%d\n", req->u.port_num.port_number);
 617                 break;
 618         case DP_ALLOCATE_PAYLOAD:
 619                 P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
 620                   req->u.allocate_payload.port_number,
 621                   req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
 622                   req->u.allocate_payload.number_sdp_streams,
 623                   req->u.allocate_payload.number_sdp_streams,
 624                   req->u.allocate_payload.sdp_stream_sink);
 625                 break;
 626         case DP_QUERY_PAYLOAD:
 627                 P("port=%d vcpi=%d\n",
 628                   req->u.query_payload.port_number,
 629                   req->u.query_payload.vcpi);
 630                 break;
 631         case DP_REMOTE_DPCD_READ:
 632                 P("port=%d dpcd_addr=%05x len=%d\n",
 633                   req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
 634                   req->u.dpcd_read.num_bytes);
 635                 break;
 636         case DP_REMOTE_DPCD_WRITE:
 637                 P("port=%d addr=%05x len=%d: %*ph\n",
 638                   req->u.dpcd_write.port_number,
 639                   req->u.dpcd_write.dpcd_address,
 640                   req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
 641                   req->u.dpcd_write.bytes);
 642                 break;
 643         case DP_REMOTE_I2C_READ:
 644                 P("port=%d num_tx=%d id=%d size=%d:\n",
 645                   req->u.i2c_read.port_number,
 646                   req->u.i2c_read.num_transactions,
 647                   req->u.i2c_read.read_i2c_device_id,
 648                   req->u.i2c_read.num_bytes_read);
 649
 650                 indent++;
 651                 for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
 652                         const struct drm_dp_remote_i2c_read_tx *rtx =
 653                                 &req->u.i2c_read.transactions[i];
 654
 655                         P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
 656                           i, rtx->i2c_dev_id, rtx->num_bytes,
 657                           rtx->no_stop_bit, rtx->i2c_transaction_delay,
 658                           rtx->num_bytes, rtx->bytes);
 659                 }
 660                 break;
 661         case DP_REMOTE_I2C_WRITE:
 662                 P("port=%d id=%d size=%d: %*ph\n",
 663                   req->u.i2c_write.port_number,
 664                   req->u.i2c_write.write_i2c_device_id,
 665                   req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
 666                   req->u.i2c_write.bytes);
 667                 break;
 668         case DP_QUERY_STREAM_ENC_STATUS:
 669                 P("stream_id=%u client_id=%*ph stream_event=%x "
 670                   "valid_event=%d stream_behavior=%x valid_behavior=%d",
 671                   req->u.enc_status.stream_id,
 672                   (int)ARRAY_SIZE(req->u.enc_status.client_id),
 673                   req->u.enc_status.client_id, req->u.enc_status.stream_event,
 674                   req->u.enc_status.valid_stream_event,
 675                   req->u.enc_status.stream_behavior,
 676                   req->u.enc_status.valid_stream_behavior);
 677                 break;
 678         default:
 679                 P("???\n");
 680                 break;
 681         }
 682 #undef P
 683 }
 684 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
 685
 686 static inline void
 687 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
 688                                 const struct drm_dp_sideband_msg_tx *txmsg)
 689 {
 690         struct drm_dp_sideband_msg_req_body req;
 691         char buf[64];
 692         int ret;
 693         int i;
 694
 695         drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
 696                               sizeof(buf));
 697         drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
 698                    txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
 699                    drm_dp_mst_sideband_tx_state_str(txmsg->state),
 700                    txmsg->path_msg, buf);
 701
 702         ret = drm_dp_decode_sideband_req(txmsg, &req);
 703         if (ret) {
 704                 drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
 705                 return;
 706         }
 707         drm_dp_dump_sideband_msg_req_body(&req, 1, p);
 708
 709         switch (req.req_type) {
 710         case DP_REMOTE_DPCD_WRITE:
 711                 kfree(req.u.dpcd_write.bytes);
 712                 break;
 713         case DP_REMOTE_I2C_READ:
 714                 for (i = 0; i < req.u.i2c_read.num_transactions; i++)
 715                         kfree(req.u.i2c_read.transactions[i].bytes);
 716                 break;
 717         case DP_REMOTE_I2C_WRITE:
 718                 kfree(req.u.i2c_write.bytes);
 719                 break;
 720         }
 721 }
 722
 723 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 724 {
 725         u8 crc4;
 726
 727         crc4 = drm_dp_msg_data_crc4(msg, len);
 728         msg[len] = crc4;
 729 }
 730
 731 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 732                                          struct drm_dp_sideband_msg_tx *raw)
 733 {
 734         int idx = 0;
 735         u8 *buf = raw->msg;
 736
 737         buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 738
 739         raw->cur_len = idx;
 740 }
 741
 742 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
 743                                           struct drm_dp_sideband_msg_hdr *hdr,
 744                                           u8 hdrlen)
 745 {
 746         /*
 747          * ignore out-of-order messages or messages that are part of a
 748          * failed transaction
 749          */
 750         if (!hdr->somt && !msg->have_somt)
 751                 return false;
 752
 753         /* get length contained in this portion */
 754         msg->curchunk_idx = 0;
 755         msg->curchunk_len = hdr->msg_len;
 756         msg->curchunk_hdrlen = hdrlen;
 757
 758         /* we have already gotten an somt - don't bother parsing */
 759         if (hdr->somt && msg->have_somt)
 760                 return false;
 761
 762         if (hdr->somt) {
 763                 memcpy(&msg->initial_hdr, hdr,
 764                        sizeof(struct drm_dp_sideband_msg_hdr));
 765                 msg->have_somt = true;
 766         }
 767         if (hdr->eomt)
 768                 msg->have_eomt = true;
 769
 770         return true;
 771 }
 772
 773 /* this adds a chunk of msg to the builder to get the final msg */
 774 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
 775                                            u8 *replybuf, u8 replybuflen)
 776 {
 777         u8 crc4;
 778
 779         memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 780         msg->curchunk_idx += replybuflen;
 781
 782         if (msg->curchunk_idx >= msg->curchunk_len) {
 783                 /* do CRC */
 784                 crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 785                 if (crc4 != msg->chunk[msg->curchunk_len - 1])
 786                         print_hex_dump(KERN_DEBUG, "wrong crc",
 787                                        DUMP_PREFIX_NONE, 16, 1,
 788                                        msg->chunk,  msg->curchunk_len, false);
 789                 /* copy chunk into bigger msg */
 790                 memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 791                 msg->curlen += msg->curchunk_len - 1;
 792         }
 793         return true;
 794 }
 795
 796 static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,
 797                                                struct drm_dp_sideband_msg_rx *raw,
 798                                                struct drm_dp_sideband_msg_reply_body *repmsg)
 799 {
 800         int idx = 1;
 801         int i;
 802
 803         memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 804         idx += 16;
 805         repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 806         idx++;
 807         if (idx > raw->curlen)
 808                 goto fail_len;
 809         for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 810                 if (raw->msg[idx] & 0x80)
 811                         repmsg->u.link_addr.ports[i].input_port = 1;
 812
 813                 repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 814                 repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 815
 816                 idx++;
 817                 if (idx > raw->curlen)
 818                         goto fail_len;
 819                 repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 820                 repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 821                 if (repmsg->u.link_addr.ports[i].input_port == 0)
 822                         repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 823                 idx++;
 824                 if (idx > raw->curlen)
 825                         goto fail_len;
 826                 if (repmsg->u.link_addr.ports[i].input_port == 0) {
 827                         repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 828                         idx++;
 829                         if (idx > raw->curlen)
 830                                 goto fail_len;
 831                         memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 832                         idx += 16;
 833                         if (idx > raw->curlen)
 834                                 goto fail_len;
 835                         repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 836                         repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 837                         idx++;
 838
 839                 }
 840                 if (idx > raw->curlen)
 841                         goto fail_len;
 842         }
 843
 844         return true;
 845 fail_len:
 846         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 847         return false;
 848 }
 849
 850 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 851                                                    struct drm_dp_sideband_msg_reply_body *repmsg)
 852 {
 853         int idx = 1;
 854
 855         repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 856         idx++;
 857         if (idx > raw->curlen)
 858                 goto fail_len;
 859         repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 860         idx++;
 861         if (idx > raw->curlen)
 862                 goto fail_len;
 863
 864         memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 865         return true;
 866 fail_len:
 867         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 868         return false;
 869 }
 870
 871 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 872                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 873 {
 874         int idx = 1;
 875
 876         repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 877         idx++;
 878         if (idx > raw->curlen)
 879                 goto fail_len;
 880         return true;
 881 fail_len:
 882         DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 883         return false;
 884 }
 885
 886 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 887                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 888 {
 889         int idx = 1;
 890
 891         repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 892         idx++;
 893         if (idx > raw->curlen)
 894                 goto fail_len;
 895         repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 896         idx++;
 897         /* TODO check */
 898         memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 899         return true;
 900 fail_len:
 901         DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 902         return false;
 903 }
 904
 905 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 906                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 907 {
 908         int idx = 1;
 909
 910         repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 911         repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
 912         idx++;
 913         if (idx > raw->curlen)
 914                 goto fail_len;
 915         repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 916         idx += 2;
 917         if (idx > raw->curlen)
 918                 goto fail_len;
 919         repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 920         idx += 2;
 921         if (idx > raw->curlen)
 922                 goto fail_len;
 923         return true;
 924 fail_len:
 925         DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 926         return false;
 927 }
 928
 929 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 930                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 931 {
 932         int idx = 1;
 933
 934         repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 935         idx++;
 936         if (idx > raw->curlen)
 937                 goto fail_len;
 938         repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 939         idx++;
 940         if (idx > raw->curlen)
 941                 goto fail_len;
 942         repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 943         idx += 2;
 944         if (idx > raw->curlen)
 945                 goto fail_len;
 946         return true;
 947 fail_len:
 948         DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 949         return false;
 950 }
 951
 952 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 953                                                     struct drm_dp_sideband_msg_reply_body *repmsg)
 954 {
 955         int idx = 1;
 956
 957         repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 958         idx++;
 959         if (idx > raw->curlen)
 960                 goto fail_len;
 961         repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 962         idx += 2;
 963         if (idx > raw->curlen)
 964                 goto fail_len;
 965         return true;
 966 fail_len:
 967         DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 968         return false;
 969 }
 970
 971 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
 972                                                        struct drm_dp_sideband_msg_reply_body *repmsg)
 973 {
 974         int idx = 1;
 975
 976         repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
 977         idx++;
 978         if (idx > raw->curlen) {
 979                 DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
 980                               idx, raw->curlen);
 981                 return false;
 982         }
 983         return true;
 984 }
 985
 986 static bool
 987 drm_dp_sideband_parse_query_stream_enc_status(
 988                                 struct drm_dp_sideband_msg_rx *raw,
 989                                 struct drm_dp_sideband_msg_reply_body *repmsg)
 990 {
 991         struct drm_dp_query_stream_enc_status_ack_reply *reply;
 992
 993         reply = &repmsg->u.enc_status;
 994
 995         reply->stream_id = raw->msg[3];
 996
 997         reply->reply_signed = raw->msg[2] & BIT(0);
 998
 999         /*
1000          * NOTE: It's my impression from reading the spec that the below parsing
1001          * is correct. However I noticed while testing with an HDCP 1.4 display
1002          * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
1003          * would expect both bits to be set. So keep the parsing following the
1004          * spec, but beware reality might not match the spec (at least for some
1005          * configurations).
1006          */
1007         reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1008         reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1009
1010         reply->query_capable_device_present = raw->msg[2] & BIT(5);
1011         reply->legacy_device_present = raw->msg[2] & BIT(6);
1012         reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1013
1014         reply->auth_completed = !!(raw->msg[1] & BIT(3));
1015         reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1016         reply->repeater_present = !!(raw->msg[1] & BIT(5));
1017         reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1018
1019         return true;
1020 }
1021
1022 static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,
1023                                         struct drm_dp_sideband_msg_rx *raw,
1024                                         struct drm_dp_sideband_msg_reply_body *msg)
1025 {
1026         memset(msg, 0, sizeof(*msg));
1027         msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1028         msg->req_type = (raw->msg[0] & 0x7f);
1029
1030         if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1031                 memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1032                 msg->u.nak.reason = raw->msg[17];
1033                 msg->u.nak.nak_data = raw->msg[18];
1034                 return false;
1035         }
1036
1037         switch (msg->req_type) {
1038         case DP_LINK_ADDRESS:
1039                 return drm_dp_sideband_parse_link_address(mgr, raw, msg);
1040         case DP_QUERY_PAYLOAD:
1041                 return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1042         case DP_REMOTE_DPCD_READ:
1043                 return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1044         case DP_REMOTE_DPCD_WRITE:
1045                 return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1046         case DP_REMOTE_I2C_READ:
1047                 return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1048         case DP_REMOTE_I2C_WRITE:
1049                 return true; /* since there's nothing to parse */
1050         case DP_ENUM_PATH_RESOURCES:
1051                 return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1052         case DP_ALLOCATE_PAYLOAD:
1053                 return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1054         case DP_POWER_DOWN_PHY:
1055         case DP_POWER_UP_PHY:
1056                 return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1057         case DP_CLEAR_PAYLOAD_ID_TABLE:
1058                 return true; /* since there's nothing to parse */
1059         case DP_QUERY_STREAM_ENC_STATUS:
1060                 return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1061         default:
1062                 drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n",
1063                         msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1064                 return false;
1065         }
1066 }
1067
1068 static bool
1069 drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1070                                                struct drm_dp_sideband_msg_rx *raw,
1071                                                struct drm_dp_sideband_msg_req_body *msg)
1072 {
1073         int idx = 1;
1074
1075         msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1076         idx++;
1077         if (idx > raw->curlen)
1078                 goto fail_len;
1079
1080         memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1081         idx += 16;
1082         if (idx > raw->curlen)
1083                 goto fail_len;
1084
1085         msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1086         msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1087         msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1088         msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1089         msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1090         idx++;
1091         return true;
1092 fail_len:
1093         drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n",
1094                     idx, raw->curlen);
1095         return false;
1096 }
1097
1098 static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1099                                                          struct drm_dp_sideband_msg_rx *raw,
1100                                                          struct drm_dp_sideband_msg_req_body *msg)
1101 {
1102         int idx = 1;
1103
1104         msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1105         idx++;
1106         if (idx > raw->curlen)
1107                 goto fail_len;
1108
1109         memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1110         idx += 16;
1111         if (idx > raw->curlen)
1112                 goto fail_len;
1113
1114         msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1115         idx++;
1116         return true;
1117 fail_len:
1118         drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen);
1119         return false;
1120 }
1121
1122 static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
1123                                       struct drm_dp_sideband_msg_rx *raw,
1124                                       struct drm_dp_sideband_msg_req_body *msg)
1125 {
1126         memset(msg, 0, sizeof(*msg));
1127         msg->req_type = (raw->msg[0] & 0x7f);
1128
1129         switch (msg->req_type) {
1130         case DP_CONNECTION_STATUS_NOTIFY:
1131                 return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg);
1132         case DP_RESOURCE_STATUS_NOTIFY:
1133                 return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg);
1134         default:
1135                 drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n",
1136                         msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1137                 return false;
1138         }
1139 }
1140
1141 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1142                              u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1143 {
1144         struct drm_dp_sideband_msg_req_body req;
1145
1146         req.req_type = DP_REMOTE_DPCD_WRITE;
1147         req.u.dpcd_write.port_number = port_num;
1148         req.u.dpcd_write.dpcd_address = offset;
1149         req.u.dpcd_write.num_bytes = num_bytes;
1150         req.u.dpcd_write.bytes = bytes;
1151         drm_dp_encode_sideband_req(&req, msg);
1152 }
1153
1154 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1155 {
1156         struct drm_dp_sideband_msg_req_body req;
1157
1158         req.req_type = DP_LINK_ADDRESS;
1159         drm_dp_encode_sideband_req(&req, msg);
1160 }
1161
1162 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1163 {
1164         struct drm_dp_sideband_msg_req_body req;
1165
1166         req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1167         drm_dp_encode_sideband_req(&req, msg);
1168         msg->path_msg = true;
1169 }
1170
1171 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1172                                      int port_num)
1173 {
1174         struct drm_dp_sideband_msg_req_body req;
1175
1176         req.req_type = DP_ENUM_PATH_RESOURCES;
1177         req.u.port_num.port_number = port_num;
1178         drm_dp_encode_sideband_req(&req, msg);
1179         msg->path_msg = true;
1180         return 0;
1181 }
1182
1183 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1184                                    int port_num,
1185                                    u8 vcpi, uint16_t pbn,
1186                                    u8 number_sdp_streams,
1187                                    u8 *sdp_stream_sink)
1188 {
1189         struct drm_dp_sideband_msg_req_body req;
1190
1191         memset(&req, 0, sizeof(req));
1192         req.req_type = DP_ALLOCATE_PAYLOAD;
1193         req.u.allocate_payload.port_number = port_num;
1194         req.u.allocate_payload.vcpi = vcpi;
1195         req.u.allocate_payload.pbn = pbn;
1196         req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1197         memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1198                    number_sdp_streams);
1199         drm_dp_encode_sideband_req(&req, msg);
1200         msg->path_msg = true;
1201 }
1202
1203 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1204                                    int port_num, bool power_up)
1205 {
1206         struct drm_dp_sideband_msg_req_body req;
1207
1208         if (power_up)
1209                 req.req_type = DP_POWER_UP_PHY;
1210         else
1211                 req.req_type = DP_POWER_DOWN_PHY;
1212
1213         req.u.port_num.port_number = port_num;
1214         drm_dp_encode_sideband_req(&req, msg);
1215         msg->path_msg = true;
1216 }
1217
1218 static int
1219 build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1220                               u8 *q_id)
1221 {
1222         struct drm_dp_sideband_msg_req_body req;
1223
1224         req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1225         req.u.enc_status.stream_id = stream_id;
1226         memcpy(req.u.enc_status.client_id, q_id,
1227                sizeof(req.u.enc_status.client_id));
1228         req.u.enc_status.stream_event = 0;
1229         req.u.enc_status.valid_stream_event = false;
1230         req.u.enc_status.stream_behavior = 0;
1231         req.u.enc_status.valid_stream_behavior = false;
1232
1233         drm_dp_encode_sideband_req(&req, msg);
1234         return 0;
1235 }
1236
1237 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1238                               struct drm_dp_sideband_msg_tx *txmsg)
1239 {
1240         unsigned int state;
1241
1242         /*
1243          * All updates to txmsg->state are protected by mgr->qlock, and the two
1244          * cases we check here are terminal states. For those the barriers
1245          * provided by the wake_up/wait_event pair are enough.
1246          */
1247         state = READ_ONCE(txmsg->state);
1248         return (state == DRM_DP_SIDEBAND_TX_RX ||
1249                 state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1250 }
1251
1252 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1253                                     struct drm_dp_sideband_msg_tx *txmsg)
1254 {
1255         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1256         unsigned long wait_timeout = msecs_to_jiffies(4000);
1257         unsigned long wait_expires = jiffies + wait_timeout;
1258         int ret;
1259
1260         for (;;) {
1261                 /*
1262                  * If the driver provides a way for this, change to
1263                  * poll-waiting for the MST reply interrupt if we didn't receive
1264                  * it for 50 msec. This would cater for cases where the HPD
1265                  * pulse signal got lost somewhere, even though the sink raised
1266                  * the corresponding MST interrupt correctly. One example is the
1267                  * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1268                  * filters out short pulses with a duration less than ~540 usec.
1269                  *
1270                  * The poll period is 50 msec to avoid missing an interrupt
1271                  * after the sink has cleared it (after a 110msec timeout
1272                  * since it raised the interrupt).
1273                  */
1274                 ret = wait_event_timeout(mgr->tx_waitq,
1275                                          check_txmsg_state(mgr, txmsg),
1276                                          mgr->cbs->poll_hpd_irq ?
1277                                                 msecs_to_jiffies(50) :
1278                                                 wait_timeout);
1279
1280                 if (ret || !mgr->cbs->poll_hpd_irq ||
1281                     time_after(jiffies, wait_expires))
1282                         break;
1283
1284                 mgr->cbs->poll_hpd_irq(mgr);
1285         }
1286
1287         mutex_lock(&mgr->qlock);
1288         if (ret > 0) {
1289                 if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1290                         ret = -EIO;
1291                         goto out;
1292                 }
1293         } else {
1294                 drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n",
1295                             txmsg, txmsg->state, txmsg->seqno);
1296
1297                 /* dump some state */
1298                 ret = -EIO;
1299
1300                 /* remove from q */
1301                 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1302                     txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1303                     txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1304                         list_del(&txmsg->next);
1305         }
1306 out:
1307         if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1308                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1309
1310                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1311         }
1312         mutex_unlock(&mgr->qlock);
1313
1314         drm_dp_mst_kick_tx(mgr);
1315         return ret;
1316 }
1317
1318 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1319 {
1320         struct drm_dp_mst_branch *mstb;
1321
1322         mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1323         if (!mstb)
1324                 return NULL;
1325
1326         mstb->lct = lct;
1327         if (lct > 1)
1328                 memcpy(mstb->rad, rad, lct / 2);
1329         INIT_LIST_HEAD(&mstb->ports);
1330         kref_init(&mstb->topology_kref);
1331         kref_init(&mstb->malloc_kref);
1332         return mstb;
1333 }
1334
1335 static void drm_dp_free_mst_branch_device(struct kref *kref)
1336 {
1337         struct drm_dp_mst_branch *mstb =
1338                 container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1339
1340         if (mstb->port_parent)
1341                 drm_dp_mst_put_port_malloc(mstb->port_parent);
1342
1343         kfree(mstb);
1344 }
1345
1346 /**
1347  * DOC: Branch device and port refcounting
1348  *
1349  * Topology refcount overview
1350  * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1351  *
1352  * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1353  * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1354  * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1355  *
1356  * Topology refcounts are not exposed to drivers, and are handled internally
1357  * by the DP MST helpers. The helpers use them in order to prevent the
1358  * in-memory topology state from being changed in the middle of critical
1359  * operations like changing the internal state of payload allocations. This
1360  * means each branch and port will be considered to be connected to the rest
1361  * of the topology until its topology refcount reaches zero. Additionally,
1362  * for ports this means that their associated &struct drm_connector will stay
1363  * registered with userspace until the port's refcount reaches 0.
1364  *
1365  * Malloc refcount overview
1366  * ~~~~~~~~~~~~~~~~~~~~~~~~
1367  *
1368  * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1369  * drm_dp_mst_branch allocated even after all of its topology references have
1370  * been dropped, so that the driver or MST helpers can safely access each
1371  * branch's last known state before it was disconnected from the topology.
1372  * When the malloc refcount of a port or branch reaches 0, the memory
1373  * allocation containing the &struct drm_dp_mst_branch or &struct
1374  * drm_dp_mst_port respectively will be freed.
1375  *
1376  * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1377  * to drivers. As of writing this documentation, there are no drivers that
1378  * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1379  * helpers. Exposing this API to drivers in a race-free manner would take more
1380  * tweaking of the refcounting scheme, however patches are welcome provided
1381  * there is a legitimate driver usecase for this.
1382  *
1383  * Refcount relationships in a topology
1384  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1385  *
1386  * Let's take a look at why the relationship between topology and malloc
1387  * refcounts is designed the way it is.
1388  *
1389  * .. kernel-figure:: dp-mst/topology-figure-1.dot
1390  *
1391  *    An example of topology and malloc refs in a DP MST topology with two
1392  *    active payloads. Topology refcount increments are indicated by solid
1393  *    lines, and malloc refcount increments are indicated by dashed lines.
1394  *    Each starts from the branch which incremented the refcount, and ends at
1395  *    the branch to which the refcount belongs to, i.e. the arrow points the
1396  *    same way as the C pointers used to reference a structure.
1397  *
1398  * As you can see in the above figure, every branch increments the topology
1399  * refcount of its children, and increments the malloc refcount of its
1400  * parent. Additionally, every payload increments the malloc refcount of its
1401  * assigned port by 1.
1402  *
1403  * So, what would happen if MSTB #3 from the above figure was unplugged from
1404  * the system, but the driver hadn't yet removed payload #2 from port #3? The
1405  * topology would start to look like the figure below.
1406  *
1407  * .. kernel-figure:: dp-mst/topology-figure-2.dot
1408  *
1409  *    Ports and branch devices which have been released from memory are
1410  *    colored grey, and references which have been removed are colored red.
1411  *
1412  * Whenever a port or branch device's topology refcount reaches zero, it will
1413  * decrement the topology refcounts of all its children, the malloc refcount
1414  * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1415  * #4, this means they both have been disconnected from the topology and freed
1416  * from memory. But, because payload #2 is still holding a reference to port
1417  * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1418  * is still accessible from memory. This also means port #3 has not yet
1419  * decremented the malloc refcount of MSTB #3, so its &struct
1420  * drm_dp_mst_branch will also stay allocated in memory until port #3's
1421  * malloc refcount reaches 0.
1422  *
1423  * This relationship is necessary because in order to release payload #2, we
1424  * need to be able to figure out the last relative of port #3 that's still
1425  * connected to the topology. In this case, we would travel up the topology as
1426  * shown below.
1427  *
1428  * .. kernel-figure:: dp-mst/topology-figure-3.dot
1429  *
1430  * And finally, remove payload #2 by communicating with port #2 through
1431  * sideband transactions.
1432  */
1433
1434 /**
1435  * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1436  * device
1437  * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1438  *
1439  * Increments &drm_dp_mst_branch.malloc_kref. When
1440  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1441  * will be released and @mstb may no longer be used.
1442  *
1443  * See also: drm_dp_mst_put_mstb_malloc()
1444  */
1445 static void
1446 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1447 {
1448         kref_get(&mstb->malloc_kref);
1449         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1450 }
1451
1452 /**
1453  * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1454  * device
1455  * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1456  *
1457  * Decrements &drm_dp_mst_branch.malloc_kref. When
1458  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1459  * will be released and @mstb may no longer be used.
1460  *
1461  * See also: drm_dp_mst_get_mstb_malloc()
1462  */
1463 static void
1464 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1465 {
1466         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1467         kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1468 }
1469
1470 static void drm_dp_free_mst_port(struct kref *kref)
1471 {
1472         struct drm_dp_mst_port *port =
1473                 container_of(kref, struct drm_dp_mst_port, malloc_kref);
1474
1475         drm_dp_mst_put_mstb_malloc(port->parent);
1476         kfree(port);
1477 }
1478
1479 /**
1480  * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1481  * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1482  *
1483  * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1484  * reaches 0, the memory allocation for @port will be released and @port may
1485  * no longer be used.
1486  *
1487  * Because @port could potentially be freed at any time by the DP MST helpers
1488  * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1489  * function, drivers that which to make use of &struct drm_dp_mst_port should
1490  * ensure that they grab at least one main malloc reference to their MST ports
1491  * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1492  * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1493  *
1494  * See also: drm_dp_mst_put_port_malloc()
1495  */
1496 void
1497 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1498 {
1499         kref_get(&port->malloc_kref);
1500         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref));
1501 }
1502 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1503
1504 /**
1505  * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1506  * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1507  *
1508  * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1509  * reaches 0, the memory allocation for @port will be released and @port may
1510  * no longer be used.
1511  *
1512  * See also: drm_dp_mst_get_port_malloc()
1513  */
1514 void
1515 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1516 {
1517         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1518         kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1519 }
1520 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1521
1522 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1523
1524 #define STACK_DEPTH 8
1525
1526 static noinline void
1527 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1528                     struct drm_dp_mst_topology_ref_history *history,
1529                     enum drm_dp_mst_topology_ref_type type)
1530 {
1531         struct drm_dp_mst_topology_ref_entry *entry = NULL;
1532         depot_stack_handle_t backtrace;
1533         ulong stack_entries[STACK_DEPTH];
1534         uint n;
1535         int i;
1536
1537         n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1538         backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1539         if (!backtrace)
1540                 return;
1541
1542         /* Try to find an existing entry for this backtrace */
1543         for (i = 0; i < history->len; i++) {
1544                 if (history->entries[i].backtrace == backtrace) {
1545                         entry = &history->entries[i];
1546                         break;
1547                 }
1548         }
1549
1550         /* Otherwise add one */
1551         if (!entry) {
1552                 struct drm_dp_mst_topology_ref_entry *new;
1553                 int new_len = history->len + 1;
1554
1555                 new = krealloc(history->entries, sizeof(*new) * new_len,
1556                                GFP_KERNEL);
1557                 if (!new)
1558                         return;
1559
1560                 entry = &new[history->len];
1561                 history->len = new_len;
1562                 history->entries = new;
1563
1564                 entry->backtrace = backtrace;
1565                 entry->type = type;
1566                 entry->count = 0;
1567         }
1568         entry->count++;
1569         entry->ts_nsec = ktime_get_ns();
1570 }
1571
1572 static int
1573 topology_ref_history_cmp(const void *a, const void *b)
1574 {
1575         const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1576
1577         if (entry_a->ts_nsec > entry_b->ts_nsec)
1578                 return 1;
1579         else if (entry_a->ts_nsec < entry_b->ts_nsec)
1580                 return -1;
1581         else
1582                 return 0;
1583 }
1584
1585 static inline const char *
1586 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1587 {
1588         if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1589                 return "get";
1590         else
1591                 return "put";
1592 }
1593
1594 static void
1595 __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1596                             void *ptr, const char *type_str)
1597 {
1598         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1599         char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1600         int i;
1601
1602         if (!buf)
1603                 return;
1604
1605         if (!history->len)
1606                 goto out;
1607
1608         /* First, sort the list so that it goes from oldest to newest
1609          * reference entry
1610          */
1611         sort(history->entries, history->len, sizeof(*history->entries),
1612              topology_ref_history_cmp, NULL);
1613
1614         drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1615                    type_str, ptr);
1616
1617         for (i = 0; i < history->len; i++) {
1618                 const struct drm_dp_mst_topology_ref_entry *entry =
1619                         &history->entries[i];
1620                 u64 ts_nsec = entry->ts_nsec;
1621                 u32 rem_nsec = do_div(ts_nsec, 1000000000);
1622
1623                 stack_depot_snprint(entry->backtrace, buf, PAGE_SIZE, 4);
1624
1625                 drm_printf(&p, "  %d %ss (last at %5llu.%06u):\n%s",
1626                            entry->count,
1627                            topology_ref_type_to_str(entry->type),
1628                            ts_nsec, rem_nsec / 1000, buf);
1629         }
1630
1631         /* Now free the history, since this is the only time we expose it */
1632         kfree(history->entries);
1633 out:
1634         kfree(buf);
1635 }
1636
1637 static __always_inline void
1638 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1639 {
1640         __dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1641                                     "MSTB");
1642 }
1643
1644 static __always_inline void
1645 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1646 {
1647         __dump_topology_ref_history(&port->topology_ref_history, port,
1648                                     "Port");
1649 }
1650
1651 static __always_inline void
1652 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1653                        enum drm_dp_mst_topology_ref_type type)
1654 {
1655         __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1656 }
1657
1658 static __always_inline void
1659 save_port_topology_ref(struct drm_dp_mst_port *port,
1660                        enum drm_dp_mst_topology_ref_type type)
1661 {
1662         __topology_ref_save(port->mgr, &port->topology_ref_history, type);
1663 }
1664
1665 static inline void
1666 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1667 {
1668         mutex_lock(&mgr->topology_ref_history_lock);
1669 }
1670
1671 static inline void
1672 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1673 {
1674         mutex_unlock(&mgr->topology_ref_history_lock);
1675 }
1676 #else
1677 static inline void
1678 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1679 static inline void
1680 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1681 static inline void
1682 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1683 static inline void
1684 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1685 #define save_mstb_topology_ref(mstb, type)
1686 #define save_port_topology_ref(port, type)
1687 #endif
1688
1689 struct drm_dp_mst_atomic_payload *
1690 drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,
1691                                  struct drm_dp_mst_port *port)
1692 {
1693         struct drm_dp_mst_atomic_payload *payload;
1694
1695         list_for_each_entry(payload, &state->payloads, next)
1696                 if (payload->port == port)
1697                         return payload;
1698
1699         return NULL;
1700 }
1701 EXPORT_SYMBOL(drm_atomic_get_mst_payload_state);
1702
1703 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1704 {
1705         struct drm_dp_mst_branch *mstb =
1706                 container_of(kref, struct drm_dp_mst_branch, topology_kref);
1707         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1708
1709         drm_dp_mst_dump_mstb_topology_history(mstb);
1710
1711         INIT_LIST_HEAD(&mstb->destroy_next);
1712
1713         /*
1714          * This can get called under mgr->mutex, so we need to perform the
1715          * actual destruction of the mstb in another worker
1716          */
1717         mutex_lock(&mgr->delayed_destroy_lock);
1718         list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1719         mutex_unlock(&mgr->delayed_destroy_lock);
1720         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1721 }
1722
1723 /**
1724  * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1725  * branch device unless it's zero
1726  * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1727  *
1728  * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1729  * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1730  * reached 0). Holding a topology reference implies that a malloc reference
1731  * will be held to @mstb as long as the user holds the topology reference.
1732  *
1733  * Care should be taken to ensure that the user has at least one malloc
1734  * reference to @mstb. If you already have a topology reference to @mstb, you
1735  * should use drm_dp_mst_topology_get_mstb() instead.
1736  *
1737  * See also:
1738  * drm_dp_mst_topology_get_mstb()
1739  * drm_dp_mst_topology_put_mstb()
1740  *
1741  * Returns:
1742  * * 1: A topology reference was grabbed successfully
1743  * * 0: @port is no longer in the topology, no reference was grabbed
1744  */
1745 static int __must_check
1746 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1747 {
1748         int ret;
1749
1750         topology_ref_history_lock(mstb->mgr);
1751         ret = kref_get_unless_zero(&mstb->topology_kref);
1752         if (ret) {
1753                 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1754                 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1755         }
1756
1757         topology_ref_history_unlock(mstb->mgr);
1758
1759         return ret;
1760 }
1761
1762 /**
1763  * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1764  * branch device
1765  * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1766  *
1767  * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1768  * not it's already reached 0. This is only valid to use in scenarios where
1769  * you are already guaranteed to have at least one active topology reference
1770  * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1771  *
1772  * See also:
1773  * drm_dp_mst_topology_try_get_mstb()
1774  * drm_dp_mst_topology_put_mstb()
1775  */
1776 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1777 {
1778         topology_ref_history_lock(mstb->mgr);
1779
1780         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1781         WARN_ON(kref_read(&mstb->topology_kref) == 0);
1782         kref_get(&mstb->topology_kref);
1783         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1784
1785         topology_ref_history_unlock(mstb->mgr);
1786 }
1787
1788 /**
1789  * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1790  * device
1791  * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1792  *
1793  * Releases a topology reference from @mstb by decrementing
1794  * &drm_dp_mst_branch.topology_kref.
1795  *
1796  * See also:
1797  * drm_dp_mst_topology_try_get_mstb()
1798  * drm_dp_mst_topology_get_mstb()
1799  */
1800 static void
1801 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1802 {
1803         topology_ref_history_lock(mstb->mgr);
1804
1805         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1);
1806         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1807
1808         topology_ref_history_unlock(mstb->mgr);
1809         kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1810 }
1811
1812 static void drm_dp_destroy_port(struct kref *kref)
1813 {
1814         struct drm_dp_mst_port *port =
1815                 container_of(kref, struct drm_dp_mst_port, topology_kref);
1816         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1817
1818         drm_dp_mst_dump_port_topology_history(port);
1819
1820         /* There's nothing that needs locking to destroy an input port yet */
1821         if (port->input) {
1822                 drm_dp_mst_put_port_malloc(port);
1823                 return;
1824         }
1825
1826         kfree(port->cached_edid);
1827
1828         /*
1829          * we can't destroy the connector here, as we might be holding the
1830          * mode_config.mutex from an EDID retrieval
1831          */
1832         mutex_lock(&mgr->delayed_destroy_lock);
1833         list_add(&port->next, &mgr->destroy_port_list);
1834         mutex_unlock(&mgr->delayed_destroy_lock);
1835         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1836 }
1837
1838 /**
1839  * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1840  * port unless it's zero
1841  * @port: &struct drm_dp_mst_port to increment the topology refcount of
1842  *
1843  * Attempts to grab a topology reference to @port, if it hasn't yet been
1844  * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1845  * 0). Holding a topology reference implies that a malloc reference will be
1846  * held to @port as long as the user holds the topology reference.
1847  *
1848  * Care should be taken to ensure that the user has at least one malloc
1849  * reference to @port. If you already have a topology reference to @port, you
1850  * should use drm_dp_mst_topology_get_port() instead.
1851  *
1852  * See also:
1853  * drm_dp_mst_topology_get_port()
1854  * drm_dp_mst_topology_put_port()
1855  *
1856  * Returns:
1857  * * 1: A topology reference was grabbed successfully
1858  * * 0: @port is no longer in the topology, no reference was grabbed
1859  */
1860 static int __must_check
1861 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1862 {
1863         int ret;
1864
1865         topology_ref_history_lock(port->mgr);
1866         ret = kref_get_unless_zero(&port->topology_kref);
1867         if (ret) {
1868                 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1869                 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1870         }
1871
1872         topology_ref_history_unlock(port->mgr);
1873         return ret;
1874 }
1875
1876 /**
1877  * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1878  * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1879  *
1880  * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1881  * not it's already reached 0. This is only valid to use in scenarios where
1882  * you are already guaranteed to have at least one active topology reference
1883  * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1884  *
1885  * See also:
1886  * drm_dp_mst_topology_try_get_port()
1887  * drm_dp_mst_topology_put_port()
1888  */
1889 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1890 {
1891         topology_ref_history_lock(port->mgr);
1892
1893         WARN_ON(kref_read(&port->topology_kref) == 0);
1894         kref_get(&port->topology_kref);
1895         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1896         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1897
1898         topology_ref_history_unlock(port->mgr);
1899 }
1900
1901 /**
1902  * drm_dp_mst_topology_put_port() - release a topology reference to a port
1903  * @port: The &struct drm_dp_mst_port to release the topology reference from
1904  *
1905  * Releases a topology reference from @port by decrementing
1906  * &drm_dp_mst_port.topology_kref.
1907  *
1908  * See also:
1909  * drm_dp_mst_topology_try_get_port()
1910  * drm_dp_mst_topology_get_port()
1911  */
1912 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1913 {
1914         topology_ref_history_lock(port->mgr);
1915
1916         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1);
1917         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1918
1919         topology_ref_history_unlock(port->mgr);
1920         kref_put(&port->topology_kref, drm_dp_destroy_port);
1921 }
1922
1923 static struct drm_dp_mst_branch *
1924 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1925                                               struct drm_dp_mst_branch *to_find)
1926 {
1927         struct drm_dp_mst_port *port;
1928         struct drm_dp_mst_branch *rmstb;
1929
1930         if (to_find == mstb)
1931                 return mstb;
1932
1933         list_for_each_entry(port, &mstb->ports, next) {
1934                 if (port->mstb) {
1935                         rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1936                             port->mstb, to_find);
1937                         if (rmstb)
1938                                 return rmstb;
1939                 }
1940         }
1941         return NULL;
1942 }
1943
1944 static struct drm_dp_mst_branch *
1945 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1946                                        struct drm_dp_mst_branch *mstb)
1947 {
1948         struct drm_dp_mst_branch *rmstb = NULL;
1949
1950         mutex_lock(&mgr->lock);
1951         if (mgr->mst_primary) {
1952                 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1953                     mgr->mst_primary, mstb);
1954
1955                 if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1956                         rmstb = NULL;
1957         }
1958         mutex_unlock(&mgr->lock);
1959         return rmstb;
1960 }
1961
1962 static struct drm_dp_mst_port *
1963 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
1964                                               struct drm_dp_mst_port *to_find)
1965 {
1966         struct drm_dp_mst_port *port, *mport;
1967
1968         list_for_each_entry(port, &mstb->ports, next) {
1969                 if (port == to_find)
1970                         return port;
1971
1972                 if (port->mstb) {
1973                         mport = drm_dp_mst_topology_get_port_validated_locked(
1974                             port->mstb, to_find);
1975                         if (mport)
1976                                 return mport;
1977                 }
1978         }
1979         return NULL;
1980 }
1981
1982 static struct drm_dp_mst_port *
1983 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
1984                                        struct drm_dp_mst_port *port)
1985 {
1986         struct drm_dp_mst_port *rport = NULL;
1987
1988         mutex_lock(&mgr->lock);
1989         if (mgr->mst_primary) {
1990                 rport = drm_dp_mst_topology_get_port_validated_locked(
1991                     mgr->mst_primary, port);
1992
1993                 if (rport && !drm_dp_mst_topology_try_get_port(rport))
1994                         rport = NULL;
1995         }
1996         mutex_unlock(&mgr->lock);
1997         return rport;
1998 }
1999
2000 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2001 {
2002         struct drm_dp_mst_port *port;
2003         int ret;
2004
2005         list_for_each_entry(port, &mstb->ports, next) {
2006                 if (port->port_num == port_num) {
2007                         ret = drm_dp_mst_topology_try_get_port(port);
2008                         return ret ? port : NULL;
2009                 }
2010         }
2011
2012         return NULL;
2013 }
2014
2015 /*
2016  * calculate a new RAD for this MST branch device
2017  * if parent has an LCT of 2 then it has 1 nibble of RAD,
2018  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2019  */
2020 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2021                                  u8 *rad)
2022 {
2023         int parent_lct = port->parent->lct;
2024         int shift = 4;
2025         int idx = (parent_lct - 1) / 2;
2026
2027         if (parent_lct > 1) {
2028                 memcpy(rad, port->parent->rad, idx + 1);
2029                 shift = (parent_lct % 2) ? 4 : 0;
2030         } else
2031                 rad[0] = 0;
2032
2033         rad[idx] |= port->port_num << shift;
2034         return parent_lct + 1;
2035 }
2036
2037 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2038 {
2039         switch (pdt) {
2040         case DP_PEER_DEVICE_DP_LEGACY_CONV:
2041         case DP_PEER_DEVICE_SST_SINK:
2042                 return true;
2043         case DP_PEER_DEVICE_MST_BRANCHING:
2044                 /* For sst branch device */
2045                 if (!mcs)
2046                         return true;
2047
2048                 return false;
2049         }
2050         return true;
2051 }
2052
2053 static int
2054 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2055                     bool new_mcs)
2056 {
2057         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2058         struct drm_dp_mst_branch *mstb;
2059         u8 rad[8], lct;
2060         int ret = 0;
2061
2062         if (port->pdt == new_pdt && port->mcs == new_mcs)
2063                 return 0;
2064
2065         /* Teardown the old pdt, if there is one */
2066         if (port->pdt != DP_PEER_DEVICE_NONE) {
2067                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2068                         /*
2069                          * If the new PDT would also have an i2c bus,
2070                          * don't bother with reregistering it
2071                          */
2072                         if (new_pdt != DP_PEER_DEVICE_NONE &&
2073                             drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2074                                 port->pdt = new_pdt;
2075                                 port->mcs = new_mcs;
2076                                 return 0;
2077                         }
2078
2079                         /* remove i2c over sideband */
2080                         drm_dp_mst_unregister_i2c_bus(port);
2081                 } else {
2082                         mutex_lock(&mgr->lock);
2083                         drm_dp_mst_topology_put_mstb(port->mstb);
2084                         port->mstb = NULL;
2085                         mutex_unlock(&mgr->lock);
2086                 }
2087         }
2088
2089         port->pdt = new_pdt;
2090         port->mcs = new_mcs;
2091
2092         if (port->pdt != DP_PEER_DEVICE_NONE) {
2093                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2094                         /* add i2c over sideband */
2095                         ret = drm_dp_mst_register_i2c_bus(port);
2096                 } else {
2097                         lct = drm_dp_calculate_rad(port, rad);
2098                         mstb = drm_dp_add_mst_branch_device(lct, rad);
2099                         if (!mstb) {
2100                                 ret = -ENOMEM;
2101                                 drm_err(mgr->dev, "Failed to create MSTB for port %p", port);
2102                                 goto out;
2103                         }
2104
2105                         mutex_lock(&mgr->lock);
2106                         port->mstb = mstb;
2107                         mstb->mgr = port->mgr;
2108                         mstb->port_parent = port;
2109
2110                         /*
2111                          * Make sure this port's memory allocation stays
2112                          * around until its child MSTB releases it
2113                          */
2114                         drm_dp_mst_get_port_malloc(port);
2115                         mutex_unlock(&mgr->lock);
2116
2117                         /* And make sure we send a link address for this */
2118                         ret = 1;
2119                 }
2120         }
2121
2122 out:
2123         if (ret < 0)
2124                 port->pdt = DP_PEER_DEVICE_NONE;
2125         return ret;
2126 }
2127
2128 /**
2129  * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2130  * @aux: Fake sideband AUX CH
2131  * @offset: address of the (first) register to read
2132  * @buffer: buffer to store the register values
2133  * @size: number of bytes in @buffer
2134  *
2135  * Performs the same functionality for remote devices via
2136  * sideband messaging as drm_dp_dpcd_read() does for local
2137  * devices via actual AUX CH.
2138  *
2139  * Return: Number of bytes read, or negative error code on failure.
2140  */
2141 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2142                              unsigned int offset, void *buffer, size_t size)
2143 {
2144         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2145                                                     aux);
2146
2147         return drm_dp_send_dpcd_read(port->mgr, port,
2148                                      offset, size, buffer);
2149 }
2150
2151 /**
2152  * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2153  * @aux: Fake sideband AUX CH
2154  * @offset: address of the (first) register to write
2155  * @buffer: buffer containing the values to write
2156  * @size: number of bytes in @buffer
2157  *
2158  * Performs the same functionality for remote devices via
2159  * sideband messaging as drm_dp_dpcd_write() does for local
2160  * devices via actual AUX CH.
2161  *
2162  * Return: number of bytes written on success, negative error code on failure.
2163  */
2164 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2165                               unsigned int offset, void *buffer, size_t size)
2166 {
2167         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2168                                                     aux);
2169
2170         return drm_dp_send_dpcd_write(port->mgr, port,
2171                                       offset, size, buffer);
2172 }
2173
2174 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2175 {
2176         int ret = 0;
2177
2178         memcpy(mstb->guid, guid, 16);
2179
2180         if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2181                 if (mstb->port_parent) {
2182                         ret = drm_dp_send_dpcd_write(mstb->mgr,
2183                                                      mstb->port_parent,
2184                                                      DP_GUID, 16, mstb->guid);
2185                 } else {
2186                         ret = drm_dp_dpcd_write(mstb->mgr->aux,
2187                                                 DP_GUID, mstb->guid, 16);
2188                 }
2189         }
2190
2191         if (ret < 16 && ret > 0)
2192                 return -EPROTO;
2193
2194         return ret == 16 ? 0 : ret;
2195 }
2196
2197 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2198                                 int pnum,
2199                                 char *proppath,
2200                                 size_t proppath_size)
2201 {
2202         int i;
2203         char temp[8];
2204
2205         snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2206         for (i = 0; i < (mstb->lct - 1); i++) {
2207                 int shift = (i % 2) ? 0 : 4;
2208                 int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2209
2210                 snprintf(temp, sizeof(temp), "-%d", port_num);
2211                 strlcat(proppath, temp, proppath_size);
2212         }
2213         snprintf(temp, sizeof(temp), "-%d", pnum);
2214         strlcat(proppath, temp, proppath_size);
2215 }
2216
2217 /**
2218  * drm_dp_mst_connector_late_register() - Late MST connector registration
2219  * @connector: The MST connector
2220  * @port: The MST port for this connector
2221  *
2222  * Helper to register the remote aux device for this MST port. Drivers should
2223  * call this from their mst connector's late_register hook to enable MST aux
2224  * devices.
2225  *
2226  * Return: 0 on success, negative error code on failure.
2227  */
2228 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2229                                        struct drm_dp_mst_port *port)
2230 {
2231         drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
2232                     port->aux.name, connector->kdev->kobj.name);
2233
2234         port->aux.dev = connector->kdev;
2235         return drm_dp_aux_register_devnode(&port->aux);
2236 }
2237 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2238
2239 /**
2240  * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2241  * @connector: The MST connector
2242  * @port: The MST port for this connector
2243  *
2244  * Helper to unregister the remote aux device for this MST port, registered by
2245  * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2246  * connector's early_unregister hook.
2247  */
2248 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2249                                            struct drm_dp_mst_port *port)
2250 {
2251         drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
2252                     port->aux.name, connector->kdev->kobj.name);
2253         drm_dp_aux_unregister_devnode(&port->aux);
2254 }
2255 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2256
2257 static void
2258 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2259                               struct drm_dp_mst_port *port)
2260 {
2261         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2262         char proppath[255];
2263         int ret;
2264
2265         build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2266         port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2267         if (!port->connector) {
2268                 ret = -ENOMEM;
2269                 goto error;
2270         }
2271
2272         if (port->pdt != DP_PEER_DEVICE_NONE &&
2273             drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
2274             port->port_num >= DP_MST_LOGICAL_PORT_0)
2275                 port->cached_edid = drm_get_edid(port->connector,
2276                                                  &port->aux.ddc);
2277
2278         drm_connector_register(port->connector);
2279         return;
2280
2281 error:
2282         drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret);
2283 }
2284
2285 /*
2286  * Drop a topology reference, and unlink the port from the in-memory topology
2287  * layout
2288  */
2289 static void
2290 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2291                                 struct drm_dp_mst_port *port)
2292 {
2293         mutex_lock(&mgr->lock);
2294         port->parent->num_ports--;
2295         list_del(&port->next);
2296         mutex_unlock(&mgr->lock);
2297         drm_dp_mst_topology_put_port(port);
2298 }
2299
2300 static struct drm_dp_mst_port *
2301 drm_dp_mst_add_port(struct drm_device *dev,
2302                     struct drm_dp_mst_topology_mgr *mgr,
2303                     struct drm_dp_mst_branch *mstb, u8 port_number)
2304 {
2305         struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2306
2307         if (!port)
2308                 return NULL;
2309
2310         kref_init(&port->topology_kref);
2311         kref_init(&port->malloc_kref);
2312         port->parent = mstb;
2313         port->port_num = port_number;
2314         port->mgr = mgr;
2315         port->aux.name = "DPMST";
2316         port->aux.dev = dev->dev;
2317         port->aux.is_remote = true;
2318
2319         /* initialize the MST downstream port's AUX crc work queue */
2320         port->aux.drm_dev = dev;
2321         drm_dp_remote_aux_init(&port->aux);
2322
2323         /*
2324          * Make sure the memory allocation for our parent branch stays
2325          * around until our own memory allocation is released
2326          */
2327         drm_dp_mst_get_mstb_malloc(mstb);
2328
2329         return port;
2330 }
2331
2332 static int
2333 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2334                                     struct drm_device *dev,
2335                                     struct drm_dp_link_addr_reply_port *port_msg)
2336 {
2337         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2338         struct drm_dp_mst_port *port;
2339         int old_ddps = 0, ret;
2340         u8 new_pdt = DP_PEER_DEVICE_NONE;
2341         bool new_mcs = 0;
2342         bool created = false, send_link_addr = false, changed = false;
2343
2344         port = drm_dp_get_port(mstb, port_msg->port_number);
2345         if (!port) {
2346                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2347                                            port_msg->port_number);
2348                 if (!port)
2349                         return -ENOMEM;
2350                 created = true;
2351                 changed = true;
2352         } else if (!port->input && port_msg->input_port && port->connector) {
2353                 /* Since port->connector can't be changed here, we create a
2354                  * new port if input_port changes from 0 to 1
2355                  */
2356                 drm_dp_mst_topology_unlink_port(mgr, port);
2357                 drm_dp_mst_topology_put_port(port);
2358                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2359                                            port_msg->port_number);
2360                 if (!port)
2361                         return -ENOMEM;
2362                 changed = true;
2363                 created = true;
2364         } else if (port->input && !port_msg->input_port) {
2365                 changed = true;
2366         } else if (port->connector) {
2367                 /* We're updating a port that's exposed to userspace, so do it
2368                  * under lock
2369                  */
2370                 drm_modeset_lock(&mgr->base.lock, NULL);
2371
2372                 old_ddps = port->ddps;
2373                 changed = port->ddps != port_msg->ddps ||
2374                         (port->ddps &&
2375                          (port->ldps != port_msg->legacy_device_plug_status ||
2376                           port->dpcd_rev != port_msg->dpcd_revision ||
2377                           port->mcs != port_msg->mcs ||
2378                           port->pdt != port_msg->peer_device_type ||
2379                           port->num_sdp_stream_sinks !=
2380                           port_msg->num_sdp_stream_sinks));
2381         }
2382
2383         port->input = port_msg->input_port;
2384         if (!port->input)
2385                 new_pdt = port_msg->peer_device_type;
2386         new_mcs = port_msg->mcs;
2387         port->ddps = port_msg->ddps;
2388         port->ldps = port_msg->legacy_device_plug_status;
2389         port->dpcd_rev = port_msg->dpcd_revision;
2390         port->num_sdp_streams = port_msg->num_sdp_streams;
2391         port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2392
2393         /* manage mstb port lists with mgr lock - take a reference
2394            for this list */
2395         if (created) {
2396                 mutex_lock(&mgr->lock);
2397                 drm_dp_mst_topology_get_port(port);
2398                 list_add(&port->next, &mstb->ports);
2399                 mstb->num_ports++;
2400                 mutex_unlock(&mgr->lock);
2401         }
2402
2403         /*
2404          * Reprobe PBN caps on both hotplug, and when re-probing the link
2405          * for our parent mstb
2406          */
2407         if (old_ddps != port->ddps || !created) {
2408                 if (port->ddps && !port->input) {
2409                         ret = drm_dp_send_enum_path_resources(mgr, mstb,
2410                                                               port);
2411                         if (ret == 1)
2412                                 changed = true;
2413                 } else {
2414                         port->full_pbn = 0;
2415                 }
2416         }
2417
2418         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2419         if (ret == 1) {
2420                 send_link_addr = true;
2421         } else if (ret < 0) {
2422                 drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret);
2423                 goto fail;
2424         }
2425
2426         /*
2427          * If this port wasn't just created, then we're reprobing because
2428          * we're coming out of suspend. In this case, always resend the link
2429          * address if there's an MSTB on this port
2430          */
2431         if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2432             port->mcs)
2433                 send_link_addr = true;
2434
2435         if (port->connector)
2436                 drm_modeset_unlock(&mgr->base.lock);
2437         else if (!port->input)
2438                 drm_dp_mst_port_add_connector(mstb, port);
2439
2440         if (send_link_addr && port->mstb) {
2441                 ret = drm_dp_send_link_address(mgr, port->mstb);
2442                 if (ret == 1) /* MSTB below us changed */
2443                         changed = true;
2444                 else if (ret < 0)
2445                         goto fail_put;
2446         }
2447
2448         /* put reference to this port */
2449         drm_dp_mst_topology_put_port(port);
2450         return changed;
2451
2452 fail:
2453         drm_dp_mst_topology_unlink_port(mgr, port);
2454         if (port->connector)
2455                 drm_modeset_unlock(&mgr->base.lock);
2456 fail_put:
2457         drm_dp_mst_topology_put_port(port);
2458         return ret;
2459 }
2460
2461 static int
2462 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2463                             struct drm_dp_connection_status_notify *conn_stat)
2464 {
2465         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2466         struct drm_dp_mst_port *port;
2467         int old_ddps, ret;
2468         u8 new_pdt;
2469         bool new_mcs;
2470         bool dowork = false, create_connector = false;
2471
2472         port = drm_dp_get_port(mstb, conn_stat->port_number);
2473         if (!port)
2474                 return 0;
2475
2476         if (port->connector) {
2477                 if (!port->input && conn_stat->input_port) {
2478                         /*
2479                          * We can't remove a connector from an already exposed
2480                          * port, so just throw the port out and make sure we
2481                          * reprobe the link address of it's parent MSTB
2482                          */
2483                         drm_dp_mst_topology_unlink_port(mgr, port);
2484                         mstb->link_address_sent = false;
2485                         dowork = true;
2486                         goto out;
2487                 }
2488
2489                 /* Locking is only needed if the port's exposed to userspace */
2490                 drm_modeset_lock(&mgr->base.lock, NULL);
2491         } else if (port->input && !conn_stat->input_port) {
2492                 create_connector = true;
2493                 /* Reprobe link address so we get num_sdp_streams */
2494                 mstb->link_address_sent = false;
2495                 dowork = true;
2496         }
2497
2498         old_ddps = port->ddps;
2499         port->input = conn_stat->input_port;
2500         port->ldps = conn_stat->legacy_device_plug_status;
2501         port->ddps = conn_stat->displayport_device_plug_status;
2502
2503         if (old_ddps != port->ddps) {
2504                 if (port->ddps && !port->input)
2505                         drm_dp_send_enum_path_resources(mgr, mstb, port);
2506                 else
2507                         port->full_pbn = 0;
2508         }
2509
2510         new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2511         new_mcs = conn_stat->message_capability_status;
2512         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2513         if (ret == 1) {
2514                 dowork = true;
2515         } else if (ret < 0) {
2516                 drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret);
2517                 dowork = false;
2518         }
2519
2520         if (port->connector)
2521                 drm_modeset_unlock(&mgr->base.lock);
2522         else if (create_connector)
2523                 drm_dp_mst_port_add_connector(mstb, port);
2524
2525 out:
2526         drm_dp_mst_topology_put_port(port);
2527         return dowork;
2528 }
2529
2530 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2531                                                                u8 lct, u8 *rad)
2532 {
2533         struct drm_dp_mst_branch *mstb;
2534         struct drm_dp_mst_port *port;
2535         int i, ret;
2536         /* find the port by iterating down */
2537
2538         mutex_lock(&mgr->lock);
2539         mstb = mgr->mst_primary;
2540
2541         if (!mstb)
2542                 goto out;
2543
2544         for (i = 0; i < lct - 1; i++) {
2545                 int shift = (i % 2) ? 0 : 4;
2546                 int port_num = (rad[i / 2] >> shift) & 0xf;
2547
2548                 list_for_each_entry(port, &mstb->ports, next) {
2549                         if (port->port_num == port_num) {
2550                                 mstb = port->mstb;
2551                                 if (!mstb) {
2552                                         drm_err(mgr->dev,
2553                                                 "failed to lookup MSTB with lct %d, rad %02x\n",
2554                                                 lct, rad[0]);
2555                                         goto out;
2556                                 }
2557
2558                                 break;
2559                         }
2560                 }
2561         }
2562         ret = drm_dp_mst_topology_try_get_mstb(mstb);
2563         if (!ret)
2564                 mstb = NULL;
2565 out:
2566         mutex_unlock(&mgr->lock);
2567         return mstb;
2568 }
2569
2570 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2571         struct drm_dp_mst_branch *mstb,
2572         const uint8_t *guid)
2573 {
2574         struct drm_dp_mst_branch *found_mstb;
2575         struct drm_dp_mst_port *port;
2576
2577         if (memcmp(mstb->guid, guid, 16) == 0)
2578                 return mstb;
2579
2580
2581         list_for_each_entry(port, &mstb->ports, next) {
2582                 if (!port->mstb)
2583                         continue;
2584
2585                 found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2586
2587                 if (found_mstb)
2588                         return found_mstb;
2589         }
2590
2591         return NULL;
2592 }
2593
2594 static struct drm_dp_mst_branch *
2595 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2596                                      const uint8_t *guid)
2597 {
2598         struct drm_dp_mst_branch *mstb;
2599         int ret;
2600
2601         /* find the port by iterating down */
2602         mutex_lock(&mgr->lock);
2603
2604         mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2605         if (mstb) {
2606                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2607                 if (!ret)
2608                         mstb = NULL;
2609         }
2610
2611         mutex_unlock(&mgr->lock);
2612         return mstb;
2613 }
2614
2615 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2616                                                struct drm_dp_mst_branch *mstb)
2617 {
2618         struct drm_dp_mst_port *port;
2619         int ret;
2620         bool changed = false;
2621
2622         if (!mstb->link_address_sent) {
2623                 ret = drm_dp_send_link_address(mgr, mstb);
2624                 if (ret == 1)
2625                         changed = true;
2626                 else if (ret < 0)
2627                         return ret;
2628         }
2629
2630         list_for_each_entry(port, &mstb->ports, next) {
2631                 if (port->input || !port->ddps || !port->mstb)
2632                         continue;
2633
2634                 ret = drm_dp_check_and_send_link_address(mgr, port->mstb);
2635                 if (ret == 1)
2636                         changed = true;
2637                 else if (ret < 0)
2638                         return ret;
2639         }
2640
2641         return changed;
2642 }
2643
2644 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2645 {
2646         struct drm_dp_mst_topology_mgr *mgr =
2647                 container_of(work, struct drm_dp_mst_topology_mgr, work);
2648         struct drm_device *dev = mgr->dev;
2649         struct drm_dp_mst_branch *mstb;
2650         int ret;
2651         bool clear_payload_id_table;
2652
2653         mutex_lock(&mgr->probe_lock);
2654
2655         mutex_lock(&mgr->lock);
2656         clear_payload_id_table = !mgr->payload_id_table_cleared;
2657         mgr->payload_id_table_cleared = true;
2658
2659         mstb = mgr->mst_primary;
2660         if (mstb) {
2661                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2662                 if (!ret)
2663                         mstb = NULL;
2664         }
2665         mutex_unlock(&mgr->lock);
2666         if (!mstb) {
2667                 mutex_unlock(&mgr->probe_lock);
2668                 return;
2669         }
2670
2671         /*
2672          * Certain branch devices seem to incorrectly report an available_pbn
2673          * of 0 on downstream sinks, even after clearing the
2674          * DP_PAYLOAD_ALLOCATE_* registers in
2675          * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2676          * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2677          * things work again.
2678          */
2679         if (clear_payload_id_table) {
2680                 drm_dbg_kms(dev, "Clearing payload ID table\n");
2681                 drm_dp_send_clear_payload_id_table(mgr, mstb);
2682         }
2683
2684         ret = drm_dp_check_and_send_link_address(mgr, mstb);
2685         drm_dp_mst_topology_put_mstb(mstb);
2686
2687         mutex_unlock(&mgr->probe_lock);
2688         if (ret > 0)
2689                 drm_kms_helper_hotplug_event(dev);
2690 }
2691
2692 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2693                                  u8 *guid)
2694 {
2695         u64 salt;
2696
2697         if (memchr_inv(guid, 0, 16))
2698                 return true;
2699
2700         salt = get_jiffies_64();
2701
2702         memcpy(&guid[0], &salt, sizeof(u64));
2703         memcpy(&guid[8], &salt, sizeof(u64));
2704
2705         return false;
2706 }
2707
2708 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2709                             u8 port_num, u32 offset, u8 num_bytes)
2710 {
2711         struct drm_dp_sideband_msg_req_body req;
2712
2713         req.req_type = DP_REMOTE_DPCD_READ;
2714         req.u.dpcd_read.port_number = port_num;
2715         req.u.dpcd_read.dpcd_address = offset;
2716         req.u.dpcd_read.num_bytes = num_bytes;
2717         drm_dp_encode_sideband_req(&req, msg);
2718 }
2719
2720 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2721                                     bool up, u8 *msg, int len)
2722 {
2723         int ret;
2724         int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2725         int tosend, total, offset;
2726         int retries = 0;
2727
2728 retry:
2729         total = len;
2730         offset = 0;
2731         do {
2732                 tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2733
2734                 ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2735                                         &msg[offset],
2736                                         tosend);
2737                 if (ret != tosend) {
2738                         if (ret == -EIO && retries < 5) {
2739                                 retries++;
2740                                 goto retry;
2741                         }
2742                         drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret);
2743
2744                         return -EIO;
2745                 }
2746                 offset += tosend;
2747                 total -= tosend;
2748         } while (total > 0);
2749         return 0;
2750 }
2751
2752 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2753                                   struct drm_dp_sideband_msg_tx *txmsg)
2754 {
2755         struct drm_dp_mst_branch *mstb = txmsg->dst;
2756         u8 req_type;
2757
2758         req_type = txmsg->msg[0] & 0x7f;
2759         if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2760                 req_type == DP_RESOURCE_STATUS_NOTIFY ||
2761                 req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
2762                 hdr->broadcast = 1;
2763         else
2764                 hdr->broadcast = 0;
2765         hdr->path_msg = txmsg->path_msg;
2766         if (hdr->broadcast) {
2767                 hdr->lct = 1;
2768                 hdr->lcr = 6;
2769         } else {
2770                 hdr->lct = mstb->lct;
2771                 hdr->lcr = mstb->lct - 1;
2772         }
2773
2774         memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
2775
2776         return 0;
2777 }
2778 /*
2779  * process a single block of the next message in the sideband queue
2780  */
2781 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2782                                    struct drm_dp_sideband_msg_tx *txmsg,
2783                                    bool up)
2784 {
2785         u8 chunk[48];
2786         struct drm_dp_sideband_msg_hdr hdr;
2787         int len, space, idx, tosend;
2788         int ret;
2789
2790         if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2791                 return 0;
2792
2793         memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2794
2795         if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2796                 txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2797
2798         /* make hdr from dst mst */
2799         ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2800         if (ret < 0)
2801                 return ret;
2802
2803         /* amount left to send in this message */
2804         len = txmsg->cur_len - txmsg->cur_offset;
2805
2806         /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2807         space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2808
2809         tosend = min(len, space);
2810         if (len == txmsg->cur_len)
2811                 hdr.somt = 1;
2812         if (space >= len)
2813                 hdr.eomt = 1;
2814
2815
2816         hdr.msg_len = tosend + 1;
2817         drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2818         memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2819         /* add crc at end */
2820         drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2821         idx += tosend + 1;
2822
2823         ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2824         if (ret) {
2825                 if (drm_debug_enabled(DRM_UT_DP)) {
2826                         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2827
2828                         drm_printf(&p, "sideband msg failed to send\n");
2829                         drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2830                 }
2831                 return ret;
2832         }
2833
2834         txmsg->cur_offset += tosend;
2835         if (txmsg->cur_offset == txmsg->cur_len) {
2836                 txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2837                 return 1;
2838         }
2839         return 0;
2840 }
2841
2842 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2843 {
2844         struct drm_dp_sideband_msg_tx *txmsg;
2845         int ret;
2846
2847         WARN_ON(!mutex_is_locked(&mgr->qlock));
2848
2849         /* construct a chunk from the first msg in the tx_msg queue */
2850         if (list_empty(&mgr->tx_msg_downq))
2851                 return;
2852
2853         txmsg = list_first_entry(&mgr->tx_msg_downq,
2854                                  struct drm_dp_sideband_msg_tx, next);
2855         ret = process_single_tx_qlock(mgr, txmsg, false);
2856         if (ret < 0) {
2857                 drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret);
2858                 list_del(&txmsg->next);
2859                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2860                 wake_up_all(&mgr->tx_waitq);
2861         }
2862 }
2863
2864 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2865                                  struct drm_dp_sideband_msg_tx *txmsg)
2866 {
2867         mutex_lock(&mgr->qlock);
2868         list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2869
2870         if (drm_debug_enabled(DRM_UT_DP)) {
2871                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2872
2873                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2874         }
2875
2876         if (list_is_singular(&mgr->tx_msg_downq))
2877                 process_single_down_tx_qlock(mgr);
2878         mutex_unlock(&mgr->qlock);
2879 }
2880
2881 static void
2882 drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr,
2883                          struct drm_dp_link_address_ack_reply *reply)
2884 {
2885         struct drm_dp_link_addr_reply_port *port_reply;
2886         int i;
2887
2888         for (i = 0; i < reply->nports; i++) {
2889                 port_reply = &reply->ports[i];
2890                 drm_dbg_kms(mgr->dev,
2891                             "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2892                             i,
2893                             port_reply->input_port,
2894                             port_reply->peer_device_type,
2895                             port_reply->port_number,
2896                             port_reply->dpcd_revision,
2897                             port_reply->mcs,
2898                             port_reply->ddps,
2899                             port_reply->legacy_device_plug_status,
2900                             port_reply->num_sdp_streams,
2901                             port_reply->num_sdp_stream_sinks);
2902         }
2903 }
2904
2905 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2906                                      struct drm_dp_mst_branch *mstb)
2907 {
2908         struct drm_dp_sideband_msg_tx *txmsg;
2909         struct drm_dp_link_address_ack_reply *reply;
2910         struct drm_dp_mst_port *port, *tmp;
2911         int i, ret, port_mask = 0;
2912         bool changed = false;
2913
2914         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2915         if (!txmsg)
2916                 return -ENOMEM;
2917
2918         txmsg->dst = mstb;
2919         build_link_address(txmsg);
2920
2921         mstb->link_address_sent = true;
2922         drm_dp_queue_down_tx(mgr, txmsg);
2923
2924         /* FIXME: Actually do some real error handling here */
2925         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2926         if (ret <= 0) {
2927                 drm_err(mgr->dev, "Sending link address failed with %d\n", ret);
2928                 goto out;
2929         }
2930         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2931                 drm_err(mgr->dev, "link address NAK received\n");
2932                 ret = -EIO;
2933                 goto out;
2934         }
2935
2936         reply = &txmsg->reply.u.link_addr;
2937         drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports);
2938         drm_dp_dump_link_address(mgr, reply);
2939
2940         ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2941         if (ret) {
2942                 char buf[64];
2943
2944                 drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2945                 drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret);
2946                 goto out;
2947         }
2948
2949         for (i = 0; i < reply->nports; i++) {
2950                 port_mask |= BIT(reply->ports[i].port_number);
2951                 ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
2952                                                           &reply->ports[i]);
2953                 if (ret == 1)
2954                         changed = true;
2955                 else if (ret < 0)
2956                         goto out;
2957         }
2958
2959         /* Prune any ports that are currently a part of mstb in our in-memory
2960          * topology, but were not seen in this link address. Usually this
2961          * means that they were removed while the topology was out of sync,
2962          * e.g. during suspend/resume
2963          */
2964         mutex_lock(&mgr->lock);
2965         list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
2966                 if (port_mask & BIT(port->port_num))
2967                         continue;
2968
2969                 drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n",
2970                             port->port_num);
2971                 list_del(&port->next);
2972                 drm_dp_mst_topology_put_port(port);
2973                 changed = true;
2974         }
2975         mutex_unlock(&mgr->lock);
2976
2977 out:
2978         if (ret <= 0)
2979                 mstb->link_address_sent = false;
2980         kfree(txmsg);
2981         return ret < 0 ? ret : changed;
2982 }
2983
2984 static void
2985 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
2986                                    struct drm_dp_mst_branch *mstb)
2987 {
2988         struct drm_dp_sideband_msg_tx *txmsg;
2989         int ret;
2990
2991         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2992         if (!txmsg)
2993                 return;
2994
2995         txmsg->dst = mstb;
2996         build_clear_payload_id_table(txmsg);
2997
2998         drm_dp_queue_down_tx(mgr, txmsg);
2999
3000         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3001         if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3002                 drm_dbg_kms(mgr->dev, "clear payload table id nak received\n");
3003
3004         kfree(txmsg);
3005 }
3006
3007 static int
3008 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3009                                 struct drm_dp_mst_branch *mstb,
3010                                 struct drm_dp_mst_port *port)
3011 {
3012         struct drm_dp_enum_path_resources_ack_reply *path_res;
3013         struct drm_dp_sideband_msg_tx *txmsg;
3014         int ret;
3015
3016         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3017         if (!txmsg)
3018                 return -ENOMEM;
3019
3020         txmsg->dst = mstb;
3021         build_enum_path_resources(txmsg, port->port_num);
3022
3023         drm_dp_queue_down_tx(mgr, txmsg);
3024
3025         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3026         if (ret > 0) {
3027                 ret = 0;
3028                 path_res = &txmsg->reply.u.path_resources;
3029
3030                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3031                         drm_dbg_kms(mgr->dev, "enum path resources nak received\n");
3032                 } else {
3033                         if (port->port_num != path_res->port_number)
3034                                 DRM_ERROR("got incorrect port in response\n");
3035
3036                         drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n",
3037                                     path_res->port_number,
3038                                     path_res->full_payload_bw_number,
3039                                     path_res->avail_payload_bw_number);
3040
3041                         /*
3042                          * If something changed, make sure we send a
3043                          * hotplug
3044                          */
3045                         if (port->full_pbn != path_res->full_payload_bw_number ||
3046                             port->fec_capable != path_res->fec_capable)
3047                                 ret = 1;
3048
3049                         port->full_pbn = path_res->full_payload_bw_number;
3050                         port->fec_capable = path_res->fec_capable;
3051                 }
3052         }
3053
3054         kfree(txmsg);
3055         return ret;
3056 }
3057
3058 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3059 {
3060         if (!mstb->port_parent)
3061                 return NULL;
3062
3063         if (mstb->port_parent->mstb != mstb)
3064                 return mstb->port_parent;
3065
3066         return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3067 }
3068
3069 /*
3070  * Searches upwards in the topology starting from mstb to try to find the
3071  * closest available parent of mstb that's still connected to the rest of the
3072  * topology. This can be used in order to perform operations like releasing
3073  * payloads, where the branch device which owned the payload may no longer be
3074  * around and thus would require that the payload on the last living relative
3075  * be freed instead.
3076  */
3077 static struct drm_dp_mst_branch *
3078 drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3079                                         struct drm_dp_mst_branch *mstb,
3080                                         int *port_num)
3081 {
3082         struct drm_dp_mst_branch *rmstb = NULL;
3083         struct drm_dp_mst_port *found_port;
3084
3085         mutex_lock(&mgr->lock);
3086         if (!mgr->mst_primary)
3087                 goto out;
3088
3089         do {
3090                 found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3091                 if (!found_port)
3092                         break;
3093
3094                 if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3095                         rmstb = found_port->parent;
3096                         *port_num = found_port->port_num;
3097                 } else {
3098                         /* Search again, starting from this parent */
3099                         mstb = found_port->parent;
3100                 }
3101         } while (!rmstb);
3102 out:
3103         mutex_unlock(&mgr->lock);
3104         return rmstb;
3105 }
3106
3107 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3108                                    struct drm_dp_mst_port *port,
3109                                    int id,
3110                                    int pbn)
3111 {
3112         struct drm_dp_sideband_msg_tx *txmsg;
3113         struct drm_dp_mst_branch *mstb;
3114         int ret, port_num;
3115         u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3116         int i;
3117
3118         port_num = port->port_num;
3119         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3120         if (!mstb) {
3121                 mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3122                                                                port->parent,
3123                                                                &port_num);
3124
3125                 if (!mstb)
3126                         return -EINVAL;
3127         }
3128
3129         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3130         if (!txmsg) {
3131                 ret = -ENOMEM;
3132                 goto fail_put;
3133         }
3134
3135         for (i = 0; i < port->num_sdp_streams; i++)
3136                 sinks[i] = i;
3137
3138         txmsg->dst = mstb;
3139         build_allocate_payload(txmsg, port_num,
3140                                id,
3141                                pbn, port->num_sdp_streams, sinks);
3142
3143         drm_dp_queue_down_tx(mgr, txmsg);
3144
3145         /*
3146          * FIXME: there is a small chance that between getting the last
3147          * connected mstb and sending the payload message, the last connected
3148          * mstb could also be removed from the topology. In the future, this
3149          * needs to be fixed by restarting the
3150          * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3151          * timeout if the topology is still connected to the system.
3152          */
3153         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3154         if (ret > 0) {
3155                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3156                         ret = -EINVAL;
3157                 else
3158                         ret = 0;
3159         }
3160         kfree(txmsg);
3161 fail_put:
3162         drm_dp_mst_topology_put_mstb(mstb);
3163         return ret;
3164 }
3165
3166 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3167                                  struct drm_dp_mst_port *port, bool power_up)
3168 {
3169         struct drm_dp_sideband_msg_tx *txmsg;
3170         int ret;
3171
3172         port = drm_dp_mst_topology_get_port_validated(mgr, port);
3173         if (!port)
3174                 return -EINVAL;
3175
3176         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3177         if (!txmsg) {
3178                 drm_dp_mst_topology_put_port(port);
3179                 return -ENOMEM;
3180         }
3181
3182         txmsg->dst = port->parent;
3183         build_power_updown_phy(txmsg, port->port_num, power_up);
3184         drm_dp_queue_down_tx(mgr, txmsg);
3185
3186         ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3187         if (ret > 0) {
3188                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3189                         ret = -EINVAL;
3190                 else
3191                         ret = 0;
3192         }
3193         kfree(txmsg);
3194         drm_dp_mst_topology_put_port(port);
3195
3196         return ret;
3197 }
3198 EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3199
3200 int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3201                 struct drm_dp_mst_port *port,
3202                 struct drm_dp_query_stream_enc_status_ack_reply *status)
3203 {
3204         struct drm_dp_mst_topology_state *state;
3205         struct drm_dp_mst_atomic_payload *payload;
3206         struct drm_dp_sideband_msg_tx *txmsg;
3207         u8 nonce[7];
3208         int ret;
3209
3210         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3211         if (!txmsg)
3212                 return -ENOMEM;
3213
3214         port = drm_dp_mst_topology_get_port_validated(mgr, port);
3215         if (!port) {
3216                 ret = -EINVAL;
3217                 goto out_get_port;
3218         }
3219
3220         get_random_bytes(nonce, sizeof(nonce));
3221
3222         drm_modeset_lock(&mgr->base.lock, NULL);
3223         state = to_drm_dp_mst_topology_state(mgr->base.state);
3224         payload = drm_atomic_get_mst_payload_state(state, port);
3225
3226         /*
3227          * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3228          *  transaction at the MST Branch device directly connected to the
3229          *  Source"
3230          */
3231         txmsg->dst = mgr->mst_primary;
3232
3233         build_query_stream_enc_status(txmsg, payload->vcpi, nonce);
3234
3235         drm_dp_queue_down_tx(mgr, txmsg);
3236
3237         ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3238         if (ret < 0) {
3239                 goto out;
3240         } else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3241                 drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3242                 ret = -ENXIO;
3243                 goto out;
3244         }
3245
3246         ret = 0;
3247         memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3248
3249 out:
3250         drm_modeset_unlock(&mgr->base.lock);
3251         drm_dp_mst_topology_put_port(port);
3252 out_get_port:
3253         kfree(txmsg);
3254         return ret;
3255 }
3256 EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3257
3258 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3259                                        struct drm_dp_mst_atomic_payload *payload)
3260 {
3261         return drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot,
3262                                          payload->time_slots);
3263 }
3264
3265 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3266                                        struct drm_dp_mst_atomic_payload *payload)
3267 {
3268         int ret;
3269         struct drm_dp_mst_port *port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
3270
3271         if (!port)
3272                 return -EIO;
3273
3274         ret = drm_dp_payload_send_msg(mgr, port, payload->vcpi, payload->pbn);
3275         drm_dp_mst_topology_put_port(port);
3276         return ret;
3277 }
3278
3279 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3280                                         struct drm_dp_mst_topology_state *mst_state,
3281                                         struct drm_dp_mst_atomic_payload *payload)
3282 {
3283         drm_dbg_kms(mgr->dev, "\n");
3284
3285         /* it's okay for these to fail */
3286         drm_dp_payload_send_msg(mgr, payload->port, payload->vcpi, 0);
3287         drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot, 0);
3288
3289         return 0;
3290 }
3291
3292 /**
3293  * drm_dp_add_payload_part1() - Execute payload update part 1
3294  * @mgr: Manager to use.
3295  * @mst_state: The MST atomic state
3296  * @payload: The payload to write
3297  *
3298  * Determines the starting time slot for the given payload, and programs the VCPI for this payload
3299  * into hardware. After calling this, the driver should generate ACT and payload packets.
3300  *
3301  * Returns: 0 on success, error code on failure. In the event that this fails,
3302  * @payload.vc_start_slot will also be set to -1.
3303  */
3304 int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
3305                              struct drm_dp_mst_topology_state *mst_state,
3306                              struct drm_dp_mst_atomic_payload *payload)
3307 {
3308         struct drm_dp_mst_port *port;
3309         int ret;
3310
3311         port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
3312         if (!port) {
3313                 drm_dbg_kms(mgr->dev,
3314                             "VCPI %d for port %p not in topology, not creating a payload\n",
3315                             payload->vcpi, payload->port);
3316                 payload->vc_start_slot = -1;
3317                 return 0;
3318         }
3319
3320         if (mgr->payload_count == 0)
3321                 mgr->next_start_slot = mst_state->start_slot;
3322
3323         payload->vc_start_slot = mgr->next_start_slot;
3324
3325         ret = drm_dp_create_payload_step1(mgr, payload);
3326         drm_dp_mst_topology_put_port(port);
3327         if (ret < 0) {
3328                 drm_warn(mgr->dev, "Failed to create MST payload for port %p: %d\n",
3329                          payload->port, ret);
3330                 payload->vc_start_slot = -1;
3331                 return ret;
3332         }
3333
3334         mgr->payload_count++;
3335         mgr->next_start_slot += payload->time_slots;
3336
3337         return 0;
3338 }
3339 EXPORT_SYMBOL(drm_dp_add_payload_part1);
3340
3341 /**
3342  * drm_dp_remove_payload() - Remove an MST payload
3343  * @mgr: Manager to use.
3344  * @mst_state: The MST atomic state
3345  * @payload: The payload to write
3346  *
3347  * Removes a payload from an MST topology if it was successfully assigned a start slot. Also updates
3348  * the starting time slots of all other payloads which would have been shifted towards the start of
3349  * the VC table as a result. After calling this, the driver should generate ACT and payload packets.
3350  */
3351 void drm_dp_remove_payload(struct drm_dp_mst_topology_mgr *mgr,
3352                            struct drm_dp_mst_topology_state *mst_state,
3353                            struct drm_dp_mst_atomic_payload *payload)
3354 {
3355         struct drm_dp_mst_atomic_payload *pos;
3356         bool send_remove = false;
3357
3358         /* We failed to make the payload, so nothing to do */
3359         if (payload->vc_start_slot == -1)
3360                 return;
3361
3362         mutex_lock(&mgr->lock);
3363         send_remove = drm_dp_mst_port_downstream_of_branch(payload->port, mgr->mst_primary);
3364         mutex_unlock(&mgr->lock);
3365
3366         if (send_remove)
3367                 drm_dp_destroy_payload_step1(mgr, mst_state, payload);
3368         else
3369                 drm_dbg_kms(mgr->dev, "Payload for VCPI %d not in topology, not sending remove\n",
3370                             payload->vcpi);
3371
3372         list_for_each_entry(pos, &mst_state->payloads, next) {
3373                 if (pos != payload && pos->vc_start_slot > payload->vc_start_slot)
3374                         pos->vc_start_slot -= payload->time_slots;
3375         }
3376         payload->vc_start_slot = -1;
3377
3378         mgr->payload_count--;
3379         mgr->next_start_slot -= payload->time_slots;
3380
3381         if (payload->delete)
3382                 drm_dp_mst_put_port_malloc(payload->port);
3383 }
3384 EXPORT_SYMBOL(drm_dp_remove_payload);
3385
3386 /**
3387  * drm_dp_add_payload_part2() - Execute payload update part 2
3388  * @mgr: Manager to use.
3389  * @state: The global atomic state
3390  * @payload: The payload to update
3391  *
3392  * If @payload was successfully assigned a starting time slot by drm_dp_add_payload_part1(), this
3393  * function will send the sideband messages to finish allocating this payload.
3394  *
3395  * Returns: 0 on success, negative error code on failure.
3396  */
3397 int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
3398                              struct drm_atomic_state *state,
3399                              struct drm_dp_mst_atomic_payload *payload)
3400 {
3401         int ret = 0;
3402
3403         /* Skip failed payloads */
3404         if (payload->vc_start_slot == -1) {
3405                 drm_dbg_kms(state->dev, "Part 1 of payload creation for %s failed, skipping part 2\n",
3406                             payload->port->connector->name);
3407                 return -EIO;
3408         }
3409
3410         ret = drm_dp_create_payload_step2(mgr, payload);
3411         if (ret < 0) {
3412                 if (!payload->delete)
3413                         drm_err(mgr->dev, "Step 2 of creating MST payload for %p failed: %d\n",
3414                                 payload->port, ret);
3415                 else
3416                         drm_dbg_kms(mgr->dev, "Step 2 of removing MST payload for %p failed: %d\n",
3417                                     payload->port, ret);
3418         }
3419
3420         return ret;
3421 }
3422 EXPORT_SYMBOL(drm_dp_add_payload_part2);
3423
3424 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3425                                  struct drm_dp_mst_port *port,
3426                                  int offset, int size, u8 *bytes)
3427 {
3428         int ret = 0;
3429         struct drm_dp_sideband_msg_tx *txmsg;
3430         struct drm_dp_mst_branch *mstb;
3431
3432         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3433         if (!mstb)
3434                 return -EINVAL;
3435
3436         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3437         if (!txmsg) {
3438                 ret = -ENOMEM;
3439                 goto fail_put;
3440         }
3441
3442         build_dpcd_read(txmsg, port->port_num, offset, size);
3443         txmsg->dst = port->parent;
3444
3445         drm_dp_queue_down_tx(mgr, txmsg);
3446
3447         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3448         if (ret < 0)
3449                 goto fail_free;
3450
3451         if (txmsg->reply.reply_type == 1) {
3452                 drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3453                             mstb, port->port_num, offset, size);
3454                 ret = -EIO;
3455                 goto fail_free;
3456         }
3457
3458         if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3459                 ret = -EPROTO;
3460                 goto fail_free;
3461         }
3462
3463         ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3464                     size);
3465         memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3466
3467 fail_free:
3468         kfree(txmsg);
3469 fail_put:
3470         drm_dp_mst_topology_put_mstb(mstb);
3471
3472         return ret;
3473 }
3474
3475 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3476                                   struct drm_dp_mst_port *port,
3477                                   int offset, int size, u8 *bytes)
3478 {
3479         int ret;
3480         struct drm_dp_sideband_msg_tx *txmsg;
3481         struct drm_dp_mst_branch *mstb;
3482
3483         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3484         if (!mstb)
3485                 return -EINVAL;
3486
3487         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3488         if (!txmsg) {
3489                 ret = -ENOMEM;
3490                 goto fail_put;
3491         }
3492
3493         build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3494         txmsg->dst = mstb;
3495
3496         drm_dp_queue_down_tx(mgr, txmsg);
3497
3498         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3499         if (ret > 0) {
3500                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3501                         ret = -EIO;
3502                 else
3503                         ret = size;
3504         }
3505
3506         kfree(txmsg);
3507 fail_put:
3508         drm_dp_mst_topology_put_mstb(mstb);
3509         return ret;
3510 }
3511
3512 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3513 {
3514         struct drm_dp_sideband_msg_reply_body reply;
3515
3516         reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3517         reply.req_type = req_type;
3518         drm_dp_encode_sideband_reply(&reply, msg);
3519         return 0;
3520 }
3521
3522 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3523                                     struct drm_dp_mst_branch *mstb,
3524                                     int req_type, bool broadcast)
3525 {
3526         struct drm_dp_sideband_msg_tx *txmsg;
3527
3528         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3529         if (!txmsg)
3530                 return -ENOMEM;
3531
3532         txmsg->dst = mstb;
3533         drm_dp_encode_up_ack_reply(txmsg, req_type);
3534
3535         mutex_lock(&mgr->qlock);
3536         /* construct a chunk from the first msg in the tx_msg queue */
3537         process_single_tx_qlock(mgr, txmsg, true);
3538         mutex_unlock(&mgr->qlock);
3539
3540         kfree(txmsg);
3541         return 0;
3542 }
3543
3544 /**
3545  * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
3546  * @mgr: The &drm_dp_mst_topology_mgr to use
3547  * @link_rate: link rate in 10kbits/s units
3548  * @link_lane_count: lane count
3549  *
3550  * Calculate the total bandwidth of a MultiStream Transport link. The returned
3551  * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
3552  * convert the number of PBNs required for a given stream to the number of
3553  * timeslots this stream requires in each MTP.
3554  */
3555 int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
3556                              int link_rate, int link_lane_count)
3557 {
3558         if (link_rate == 0 || link_lane_count == 0)
3559                 drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
3560                             link_rate, link_lane_count);
3561
3562         /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
3563         return link_rate * link_lane_count / 54000;
3564 }
3565 EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
3566
3567 /**
3568  * drm_dp_read_mst_cap() - check whether or not a sink supports MST
3569  * @aux: The DP AUX channel to use
3570  * @dpcd: A cached copy of the DPCD capabilities for this sink
3571  *
3572  * Returns: %True if the sink supports MST, %false otherwise
3573  */
3574 bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3575                          const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3576 {
3577         u8 mstm_cap;
3578
3579         if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3580                 return false;
3581
3582         if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3583                 return false;
3584
3585         return mstm_cap & DP_MST_CAP;
3586 }
3587 EXPORT_SYMBOL(drm_dp_read_mst_cap);
3588
3589 /**
3590  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3591  * @mgr: manager to set state for
3592  * @mst_state: true to enable MST on this connector - false to disable.
3593  *
3594  * This is called by the driver when it detects an MST capable device plugged
3595  * into a DP MST capable port, or when a DP MST capable device is unplugged.
3596  */
3597 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3598 {
3599         int ret = 0;
3600         struct drm_dp_mst_branch *mstb = NULL;
3601
3602         mutex_lock(&mgr->lock);
3603         if (mst_state == mgr->mst_state)
3604                 goto out_unlock;
3605
3606         mgr->mst_state = mst_state;
3607         /* set the device into MST mode */
3608         if (mst_state) {
3609                 WARN_ON(mgr->mst_primary);
3610
3611                 /* get dpcd info */
3612                 ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
3613                 if (ret < 0) {
3614                         drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n",
3615                                     mgr->aux->name, ret);
3616                         goto out_unlock;
3617                 }
3618
3619                 /* add initial branch device at LCT 1 */
3620                 mstb = drm_dp_add_mst_branch_device(1, NULL);
3621                 if (mstb == NULL) {
3622                         ret = -ENOMEM;
3623                         goto out_unlock;
3624                 }
3625                 mstb->mgr = mgr;
3626
3627                 /* give this the main reference */
3628                 mgr->mst_primary = mstb;
3629                 drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3630
3631                 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3632                                          DP_MST_EN |
3633                                          DP_UP_REQ_EN |
3634                                          DP_UPSTREAM_IS_SRC);
3635                 if (ret < 0)
3636                         goto out_unlock;
3637
3638                 /* Write reset payload */
3639                 drm_dp_dpcd_write_payload(mgr, 0, 0, 0x3f);
3640
3641                 queue_work(system_long_wq, &mgr->work);
3642
3643                 ret = 0;
3644         } else {
3645                 /* disable MST on the device */
3646                 mstb = mgr->mst_primary;
3647                 mgr->mst_primary = NULL;
3648                 /* this can fail if the device is gone */
3649                 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3650                 ret = 0;
3651                 mgr->payload_id_table_cleared = false;
3652
3653                 memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv));
3654                 memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv));
3655         }
3656
3657 out_unlock:
3658         mutex_unlock(&mgr->lock);
3659         if (mstb)
3660                 drm_dp_mst_topology_put_mstb(mstb);
3661         return ret;
3662
3663 }
3664 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3665
3666 static void
3667 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3668 {
3669         struct drm_dp_mst_port *port;
3670
3671         /* The link address will need to be re-sent on resume */
3672         mstb->link_address_sent = false;
3673
3674         list_for_each_entry(port, &mstb->ports, next)
3675                 if (port->mstb)
3676                         drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3677 }
3678
3679 /**
3680  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3681  * @mgr: manager to suspend
3682  *
3683  * This function tells the MST device that we can't handle UP messages
3684  * anymore. This should stop it from sending any since we are suspended.
3685  */
3686 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3687 {
3688         mutex_lock(&mgr->lock);
3689         drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3690                            DP_MST_EN | DP_UPSTREAM_IS_SRC);
3691         mutex_unlock(&mgr->lock);
3692         flush_work(&mgr->up_req_work);
3693         flush_work(&mgr->work);
3694         flush_work(&mgr->delayed_destroy_work);
3695
3696         mutex_lock(&mgr->lock);
3697         if (mgr->mst_state && mgr->mst_primary)
3698                 drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3699         mutex_unlock(&mgr->lock);
3700 }
3701 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3702
3703 /**
3704  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3705  * @mgr: manager to resume
3706  * @sync: whether or not to perform topology reprobing synchronously
3707  *
3708  * This will fetch DPCD and see if the device is still there,
3709  * if it is, it will rewrite the MSTM control bits, and return.
3710  *
3711  * If the device fails this returns -1, and the driver should do
3712  * a full MST reprobe, in case we were undocked.
3713  *
3714  * During system resume (where it is assumed that the driver will be calling
3715  * drm_atomic_helper_resume()) this function should be called beforehand with
3716  * @sync set to true. In contexts like runtime resume where the driver is not
3717  * expected to be calling drm_atomic_helper_resume(), this function should be
3718  * called with @sync set to false in order to avoid deadlocking.
3719  *
3720  * Returns: -1 if the MST topology was removed while we were suspended, 0
3721  * otherwise.
3722  */
3723 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3724                                    bool sync)
3725 {
3726         int ret;
3727         u8 guid[16];
3728
3729         mutex_lock(&mgr->lock);
3730         if (!mgr->mst_primary)
3731                 goto out_fail;
3732
3733         if (drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd) < 0) {
3734                 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3735                 goto out_fail;
3736         }
3737
3738         ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3739                                  DP_MST_EN |
3740                                  DP_UP_REQ_EN |
3741                                  DP_UPSTREAM_IS_SRC);
3742         if (ret < 0) {
3743                 drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");
3744                 goto out_fail;
3745         }
3746
3747         /* Some hubs forget their guids after they resume */
3748         ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3749         if (ret != 16) {
3750                 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3751                 goto out_fail;
3752         }
3753
3754         ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3755         if (ret) {
3756                 drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n");
3757                 goto out_fail;
3758         }
3759
3760         /*
3761          * For the final step of resuming the topology, we need to bring the
3762          * state of our in-memory topology back into sync with reality. So,
3763          * restart the probing process as if we're probing a new hub
3764          */
3765         queue_work(system_long_wq, &mgr->work);
3766         mutex_unlock(&mgr->lock);
3767
3768         if (sync) {
3769                 drm_dbg_kms(mgr->dev,
3770                             "Waiting for link probe work to finish re-syncing topology...\n");
3771                 flush_work(&mgr->work);
3772         }
3773
3774         return 0;
3775
3776 out_fail:
3777         mutex_unlock(&mgr->lock);
3778         return -1;
3779 }
3780 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3781
3782 static bool
3783 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3784                       struct drm_dp_mst_branch **mstb)
3785 {
3786         int len;
3787         u8 replyblock[32];
3788         int replylen, curreply;
3789         int ret;
3790         u8 hdrlen;
3791         struct drm_dp_sideband_msg_hdr hdr;
3792         struct drm_dp_sideband_msg_rx *msg =
3793                 up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3794         int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3795                            DP_SIDEBAND_MSG_DOWN_REP_BASE;
3796
3797         if (!up)
3798                 *mstb = NULL;
3799
3800         len = min(mgr->max_dpcd_transaction_bytes, 16);
3801         ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3802         if (ret != len) {
3803                 drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret);
3804                 return false;
3805         }
3806
3807         ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen);
3808         if (ret == false) {
3809                 print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3810                                1, replyblock, len, false);
3811                 drm_dbg_kms(mgr->dev, "ERROR: failed header\n");
3812                 return false;
3813         }
3814
3815         if (!up) {
3816                 /* Caller is responsible for giving back this reference */
3817                 *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3818                 if (!*mstb) {
3819                         drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct);
3820                         return false;
3821                 }
3822         }
3823
3824         if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3825                 drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]);
3826                 return false;
3827         }
3828
3829         replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3830         ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3831         if (!ret) {
3832                 drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]);
3833                 return false;
3834         }
3835
3836         replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3837         curreply = len;
3838         while (replylen > 0) {
3839                 len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3840                 ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3841                                     replyblock, len);
3842                 if (ret != len) {
3843                         drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n",
3844                                     len, ret);
3845                         return false;
3846                 }
3847
3848                 ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3849                 if (!ret) {
3850                         drm_dbg_kms(mgr->dev, "failed to build sideband msg\n");
3851                         return false;
3852                 }
3853
3854                 curreply += len;
3855                 replylen -= len;
3856         }
3857         return true;
3858 }
3859
3860 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3861 {
3862         struct drm_dp_sideband_msg_tx *txmsg;
3863         struct drm_dp_mst_branch *mstb = NULL;
3864         struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3865
3866         if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3867                 goto out_clear_reply;
3868
3869         /* Multi-packet message transmission, don't clear the reply */
3870         if (!msg->have_eomt)
3871                 goto out;
3872
3873         /* find the message */
3874         mutex_lock(&mgr->qlock);
3875         txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
3876                                          struct drm_dp_sideband_msg_tx, next);
3877         mutex_unlock(&mgr->qlock);
3878
3879         /* Were we actually expecting a response, and from this mstb? */
3880         if (!txmsg || txmsg->dst != mstb) {
3881                 struct drm_dp_sideband_msg_hdr *hdr;
3882
3883                 hdr = &msg->initial_hdr;
3884                 drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
3885                             mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
3886                 goto out_clear_reply;
3887         }
3888
3889         drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply);
3890
3891         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3892                 drm_dbg_kms(mgr->dev,
3893                             "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
3894                             txmsg->reply.req_type,
3895                             drm_dp_mst_req_type_str(txmsg->reply.req_type),
3896                             txmsg->reply.u.nak.reason,
3897                             drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
3898                             txmsg->reply.u.nak.nak_data);
3899         }
3900
3901         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3902         drm_dp_mst_topology_put_mstb(mstb);
3903
3904         mutex_lock(&mgr->qlock);
3905         txmsg->state = DRM_DP_SIDEBAND_TX_RX;
3906         list_del(&txmsg->next);
3907         mutex_unlock(&mgr->qlock);
3908
3909         wake_up_all(&mgr->tx_waitq);
3910
3911         return 0;
3912
3913 out_clear_reply:
3914         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3915 out:
3916         if (mstb)
3917                 drm_dp_mst_topology_put_mstb(mstb);
3918
3919         return 0;
3920 }
3921
3922 static inline bool
3923 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
3924                           struct drm_dp_pending_up_req *up_req)
3925 {
3926         struct drm_dp_mst_branch *mstb = NULL;
3927         struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
3928         struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
3929         bool hotplug = false, dowork = false;
3930
3931         if (hdr->broadcast) {
3932                 const u8 *guid = NULL;
3933
3934                 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
3935                         guid = msg->u.conn_stat.guid;
3936                 else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
3937                         guid = msg->u.resource_stat.guid;
3938
3939                 if (guid)
3940                         mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
3941         } else {
3942                 mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
3943         }
3944
3945         if (!mstb) {
3946                 drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct);
3947                 return false;
3948         }
3949
3950         /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
3951         if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
3952                 dowork = drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
3953                 hotplug = true;
3954         }
3955
3956         drm_dp_mst_topology_put_mstb(mstb);
3957
3958         if (dowork)
3959                 queue_work(system_long_wq, &mgr->work);
3960         return hotplug;
3961 }
3962
3963 static void drm_dp_mst_up_req_work(struct work_struct *work)
3964 {
3965         struct drm_dp_mst_topology_mgr *mgr =
3966                 container_of(work, struct drm_dp_mst_topology_mgr,
3967                              up_req_work);
3968         struct drm_dp_pending_up_req *up_req;
3969         bool send_hotplug = false;
3970
3971         mutex_lock(&mgr->probe_lock);
3972         while (true) {
3973                 mutex_lock(&mgr->up_req_lock);
3974                 up_req = list_first_entry_or_null(&mgr->up_req_list,
3975                                                   struct drm_dp_pending_up_req,
3976                                                   next);
3977                 if (up_req)
3978                         list_del(&up_req->next);
3979                 mutex_unlock(&mgr->up_req_lock);
3980
3981                 if (!up_req)
3982                         break;
3983
3984                 send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
3985                 kfree(up_req);
3986         }
3987         mutex_unlock(&mgr->probe_lock);
3988
3989         if (send_hotplug)
3990                 drm_kms_helper_hotplug_event(mgr->dev);
3991 }
3992
3993 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
3994 {
3995         struct drm_dp_pending_up_req *up_req;
3996
3997         if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
3998                 goto out;
3999
4000         if (!mgr->up_req_recv.have_eomt)
4001                 return 0;
4002
4003         up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4004         if (!up_req)
4005                 return -ENOMEM;
4006
4007         INIT_LIST_HEAD(&up_req->next);
4008
4009         drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg);
4010
4011         if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4012             up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4013                 drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
4014                             up_req->msg.req_type);
4015                 kfree(up_req);
4016                 goto out;
4017         }
4018
4019         drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4020                                  false);
4021
4022         if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4023                 const struct drm_dp_connection_status_notify *conn_stat =
4024                         &up_req->msg.u.conn_stat;
4025
4026                 drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4027                             conn_stat->port_number,
4028                             conn_stat->legacy_device_plug_status,
4029                             conn_stat->displayport_device_plug_status,
4030                             conn_stat->message_capability_status,
4031                             conn_stat->input_port,
4032                             conn_stat->peer_device_type);
4033         } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4034                 const struct drm_dp_resource_status_notify *res_stat =
4035                         &up_req->msg.u.resource_stat;
4036
4037                 drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n",
4038                             res_stat->port_number,
4039                             res_stat->available_pbn);
4040         }
4041
4042         up_req->hdr = mgr->up_req_recv.initial_hdr;
4043         mutex_lock(&mgr->up_req_lock);
4044         list_add_tail(&up_req->next, &mgr->up_req_list);
4045         mutex_unlock(&mgr->up_req_lock);
4046         queue_work(system_long_wq, &mgr->up_req_work);
4047
4048 out:
4049         memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4050         return 0;
4051 }
4052
4053 /**
4054  * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
4055  * @mgr: manager to notify irq for.
4056  * @esi: 4 bytes from SINK_COUNT_ESI
4057  * @handled: whether the hpd interrupt was consumed or not
4058  *
4059  * This should be called from the driver when it detects a short IRQ,
4060  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4061  * topology manager will process the sideband messages received as a result
4062  * of this.
4063  */
4064 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
4065 {
4066         int ret = 0;
4067         int sc;
4068         *handled = false;
4069         sc = DP_GET_SINK_COUNT(esi[0]);
4070
4071         if (sc != mgr->sink_count) {
4072                 mgr->sink_count = sc;
4073                 *handled = true;
4074         }
4075
4076         if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4077                 ret = drm_dp_mst_handle_down_rep(mgr);
4078                 *handled = true;
4079         }
4080
4081         if (esi[1] & DP_UP_REQ_MSG_RDY) {
4082                 ret |= drm_dp_mst_handle_up_req(mgr);
4083                 *handled = true;
4084         }
4085
4086         drm_dp_mst_kick_tx(mgr);
4087         return ret;
4088 }
4089 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
4090
4091 /**
4092  * drm_dp_mst_detect_port() - get connection status for an MST port
4093  * @connector: DRM connector for this port
4094  * @ctx: The acquisition context to use for grabbing locks
4095  * @mgr: manager for this port
4096  * @port: pointer to a port
4097  *
4098  * This returns the current connection state for a port.
4099  */
4100 int
4101 drm_dp_mst_detect_port(struct drm_connector *connector,
4102                        struct drm_modeset_acquire_ctx *ctx,
4103                        struct drm_dp_mst_topology_mgr *mgr,
4104                        struct drm_dp_mst_port *port)
4105 {
4106         int ret;
4107
4108         /* we need to search for the port in the mgr in case it's gone */
4109         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4110         if (!port)
4111                 return connector_status_disconnected;
4112
4113         ret = drm_modeset_lock(&mgr->base.lock, ctx);
4114         if (ret)
4115                 goto out;
4116
4117         ret = connector_status_disconnected;
4118
4119         if (!port->ddps)
4120                 goto out;
4121
4122         switch (port->pdt) {
4123         case DP_PEER_DEVICE_NONE:
4124                 break;
4125         case DP_PEER_DEVICE_MST_BRANCHING:
4126                 if (!port->mcs)
4127                         ret = connector_status_connected;
4128                 break;
4129
4130         case DP_PEER_DEVICE_SST_SINK:
4131                 ret = connector_status_connected;
4132                 /* for logical ports - cache the EDID */
4133                 if (port->port_num >= DP_MST_LOGICAL_PORT_0 && !port->cached_edid)
4134                         port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
4135                 break;
4136         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4137                 if (port->ldps)
4138                         ret = connector_status_connected;
4139                 break;
4140         }
4141 out:
4142         drm_dp_mst_topology_put_port(port);
4143         return ret;
4144 }
4145 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4146
4147 /**
4148  * drm_dp_mst_get_edid() - get EDID for an MST port
4149  * @connector: toplevel connector to get EDID for
4150  * @mgr: manager for this port
4151  * @port: unverified pointer to a port.
4152  *
4153  * This returns an EDID for the port connected to a connector,
4154  * It validates the pointer still exists so the caller doesn't require a
4155  * reference.
4156  */
4157 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4158 {
4159         struct edid *edid = NULL;
4160
4161         /* we need to search for the port in the mgr in case it's gone */
4162         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4163         if (!port)
4164                 return NULL;
4165
4166         if (port->cached_edid)
4167                 edid = drm_edid_duplicate(port->cached_edid);
4168         else {
4169                 edid = drm_get_edid(connector, &port->aux.ddc);
4170         }
4171         port->has_audio = drm_detect_monitor_audio(edid);
4172         drm_dp_mst_topology_put_port(port);
4173         return edid;
4174 }
4175 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4176
4177 /**
4178  * drm_dp_atomic_find_time_slots() - Find and add time slots to the state
4179  * @state: global atomic state
4180  * @mgr: MST topology manager for the port
4181  * @port: port to find time slots for
4182  * @pbn: bandwidth required for the mode in PBN
4183  *
4184  * Allocates time slots to @port, replacing any previous time slot allocations it may
4185  * have had. Any atomic drivers which support MST must call this function in
4186  * their &drm_encoder_helper_funcs.atomic_check() callback unconditionally to
4187  * change the current time slot allocation for the new state, and ensure the MST
4188  * atomic state is added whenever the state of payloads in the topology changes.
4189  *
4190  * Allocations set by this function are not checked against the bandwidth
4191  * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4192  *
4193  * Additionally, it is OK to call this function multiple times on the same
4194  * @port as needed. It is not OK however, to call this function and
4195  * drm_dp_atomic_release_time_slots() in the same atomic check phase.
4196  *
4197  * See also:
4198  * drm_dp_atomic_release_time_slots()
4199  * drm_dp_mst_atomic_check()
4200  *
4201  * Returns:
4202  * Total slots in the atomic state assigned for this port, or a negative error
4203  * code if the port no longer exists
4204  */
4205 int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
4206                                   struct drm_dp_mst_topology_mgr *mgr,
4207                                   struct drm_dp_mst_port *port, int pbn)
4208 {
4209         struct drm_dp_mst_topology_state *topology_state;
4210         struct drm_dp_mst_atomic_payload *payload = NULL;
4211         struct drm_connector_state *conn_state;
4212         int prev_slots = 0, prev_bw = 0, req_slots;
4213
4214         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4215         if (IS_ERR(topology_state))
4216                 return PTR_ERR(topology_state);
4217
4218         conn_state = drm_atomic_get_new_connector_state(state, port->connector);
4219         topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc);
4220
4221         /* Find the current allocation for this port, if any */
4222         payload = drm_atomic_get_mst_payload_state(topology_state, port);
4223         if (payload) {
4224                 prev_slots = payload->time_slots;
4225                 prev_bw = payload->pbn;
4226
4227                 /*
4228                  * This should never happen, unless the driver tries
4229                  * releasing and allocating the same timeslot allocation,
4230                  * which is an error
4231                  */
4232                 if (drm_WARN_ON(mgr->dev, payload->delete)) {
4233                         drm_err(mgr->dev,
4234                                 "cannot allocate and release time slots on [MST PORT:%p] in the same state\n",
4235                                 port);
4236                         return -EINVAL;
4237                 }
4238         }
4239
4240         req_slots = DIV_ROUND_UP(pbn, topology_state->pbn_div);
4241
4242         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n",
4243                        port->connector->base.id, port->connector->name,
4244                        port, prev_slots, req_slots);
4245         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4246                        port->connector->base.id, port->connector->name,
4247                        port, prev_bw, pbn);
4248
4249         /* Add the new allocation to the state, note the VCPI isn't assigned until the end */
4250         if (!payload) {
4251                 payload = kzalloc(sizeof(*payload), GFP_KERNEL);
4252                 if (!payload)
4253                         return -ENOMEM;
4254
4255                 drm_dp_mst_get_port_malloc(port);
4256                 payload->port = port;
4257                 payload->vc_start_slot = -1;
4258                 list_add(&payload->next, &topology_state->payloads);
4259         }
4260         payload->time_slots = req_slots;
4261         payload->pbn = pbn;
4262
4263         return req_slots;
4264 }
4265 EXPORT_SYMBOL(drm_dp_atomic_find_time_slots);
4266
4267 /**
4268  * drm_dp_atomic_release_time_slots() - Release allocated time slots
4269  * @state: global atomic state
4270  * @mgr: MST topology manager for the port
4271  * @port: The port to release the time slots from
4272  *
4273  * Releases any time slots that have been allocated to a port in the atomic
4274  * state. Any atomic drivers which support MST must call this function
4275  * unconditionally in their &drm_connector_helper_funcs.atomic_check() callback.
4276  * This helper will check whether time slots would be released by the new state and
4277  * respond accordingly, along with ensuring the MST state is always added to the
4278  * atomic state whenever a new state would modify the state of payloads on the
4279  * topology.
4280  *
4281  * It is OK to call this even if @port has been removed from the system.
4282  * Additionally, it is OK to call this function multiple times on the same
4283  * @port as needed. It is not OK however, to call this function and
4284  * drm_dp_atomic_find_time_slots() on the same @port in a single atomic check
4285  * phase.
4286  *
4287  * See also:
4288  * drm_dp_atomic_find_time_slots()
4289  * drm_dp_mst_atomic_check()
4290  *
4291  * Returns:
4292  * 0 on success, negative error code otherwise
4293  */
4294 int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
4295                                      struct drm_dp_mst_topology_mgr *mgr,
4296                                      struct drm_dp_mst_port *port)
4297 {
4298         struct drm_dp_mst_topology_state *topology_state;
4299         struct drm_dp_mst_atomic_payload *payload;
4300         struct drm_connector_state *old_conn_state, *new_conn_state;
4301         bool update_payload = true;
4302
4303         old_conn_state = drm_atomic_get_old_connector_state(state, port->connector);
4304         if (!old_conn_state->crtc)
4305                 return 0;
4306
4307         /* If the CRTC isn't disabled by this state, don't release it's payload */
4308         new_conn_state = drm_atomic_get_new_connector_state(state, port->connector);
4309         if (new_conn_state->crtc) {
4310                 struct drm_crtc_state *crtc_state =
4311                         drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
4312
4313                 /* No modeset means no payload changes, so it's safe to not pull in the MST state */
4314                 if (!crtc_state || !drm_atomic_crtc_needs_modeset(crtc_state))
4315                         return 0;
4316
4317                 if (!crtc_state->mode_changed && !crtc_state->connectors_changed)
4318                         update_payload = false;
4319         }
4320
4321         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4322         if (IS_ERR(topology_state))
4323                 return PTR_ERR(topology_state);
4324
4325         topology_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
4326         if (!update_payload)
4327                 return 0;
4328
4329         payload = drm_atomic_get_mst_payload_state(topology_state, port);
4330         if (WARN_ON(!payload)) {
4331                 drm_err(mgr->dev, "No payload for [MST PORT:%p] found in mst state %p\n",
4332                         port, &topology_state->base);
4333                 return -EINVAL;
4334         }
4335
4336         if (new_conn_state->crtc)
4337                 return 0;
4338
4339         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] TU %d -> 0\n", port, payload->time_slots);
4340         if (!payload->delete) {
4341                 payload->pbn = 0;
4342                 payload->delete = true;
4343                 topology_state->payload_mask &= ~BIT(payload->vcpi - 1);
4344         }
4345
4346         return 0;
4347 }
4348 EXPORT_SYMBOL(drm_dp_atomic_release_time_slots);
4349
4350 /**
4351  * drm_dp_mst_atomic_setup_commit() - setup_commit hook for MST helpers
4352  * @state: global atomic state
4353  *
4354  * This function saves all of the &drm_crtc_commit structs in an atomic state that touch any CRTCs
4355  * currently assigned to an MST topology. Drivers must call this hook from their
4356  * &drm_mode_config_helper_funcs.atomic_commit_setup hook.
4357  *
4358  * Returns:
4359  * 0 if all CRTC commits were retrieved successfully, negative error code otherwise
4360  */
4361 int drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state)
4362 {
4363         struct drm_dp_mst_topology_mgr *mgr;
4364         struct drm_dp_mst_topology_state *mst_state;
4365         struct drm_crtc *crtc;
4366         struct drm_crtc_state *crtc_state;
4367         int i, j, commit_idx, num_commit_deps;
4368
4369         for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
4370                 if (!mst_state->pending_crtc_mask)
4371                         continue;
4372
4373                 num_commit_deps = hweight32(mst_state->pending_crtc_mask);
4374                 mst_state->commit_deps = kmalloc_array(num_commit_deps,
4375                                                        sizeof(*mst_state->commit_deps), GFP_KERNEL);
4376                 if (!mst_state->commit_deps)
4377                         return -ENOMEM;
4378                 mst_state->num_commit_deps = num_commit_deps;
4379
4380                 commit_idx = 0;
4381                 for_each_new_crtc_in_state(state, crtc, crtc_state, j) {
4382                         if (mst_state->pending_crtc_mask & drm_crtc_mask(crtc)) {
4383                                 mst_state->commit_deps[commit_idx++] =
4384                                         drm_crtc_commit_get(crtc_state->commit);
4385                         }
4386                 }
4387         }
4388
4389         return 0;
4390 }
4391 EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
4392
4393 /**
4394  * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending commits on MST topologies,
4395  * prepare new MST state for commit
4396  * @state: global atomic state
4397  *
4398  * Goes through any MST topologies in this atomic state, and waits for any pending commits which
4399  * touched CRTCs that were/are on an MST topology to be programmed to hardware and flipped to before
4400  * returning. This is to prevent multiple non-blocking commits affecting an MST topology from racing
4401  * with eachother by forcing them to be executed sequentially in situations where the only resources
4402  * the modeset objects in these commits share are an MST topology.
4403  *
4404  * This function also prepares the new MST state for commit by performing some state preparation
4405  * which can't be done until this point, such as reading back the final VC start slots (which are
4406  * determined at commit-time) from the previous state.
4407  *
4408  * All MST drivers must call this function after calling drm_atomic_helper_wait_for_dependencies(),
4409  * or whatever their equivalent of that is.
4410  */
4411 void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state)
4412 {
4413         struct drm_dp_mst_topology_state *old_mst_state, *new_mst_state;
4414         struct drm_dp_mst_topology_mgr *mgr;
4415         struct drm_dp_mst_atomic_payload *old_payload, *new_payload;
4416         int i, j, ret;
4417
4418         for_each_oldnew_mst_mgr_in_state(state, mgr, old_mst_state, new_mst_state, i) {
4419                 for (j = 0; j < old_mst_state->num_commit_deps; j++) {
4420                         ret = drm_crtc_commit_wait(old_mst_state->commit_deps[j]);
4421                         if (ret < 0)
4422                                 drm_err(state->dev, "Failed to wait for %s: %d\n",
4423                                         old_mst_state->commit_deps[j]->crtc->name, ret);
4424                 }
4425
4426                 /* Now that previous state is committed, it's safe to copy over the start slot
4427                  * assignments
4428                  */
4429                 list_for_each_entry(old_payload, &old_mst_state->payloads, next) {
4430                         if (old_payload->delete)
4431                                 continue;
4432
4433                         new_payload = drm_atomic_get_mst_payload_state(new_mst_state,
4434                                                                        old_payload->port);
4435                         new_payload->vc_start_slot = old_payload->vc_start_slot;
4436                 }
4437         }
4438 }
4439 EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
4440
4441 /**
4442  * drm_dp_mst_root_conn_atomic_check() - Serialize CRTC commits on MST-capable connectors operating
4443  * in SST mode
4444  * @new_conn_state: The new connector state of the &drm_connector
4445  * @mgr: The MST topology manager for the &drm_connector
4446  *
4447  * Since MST uses fake &drm_encoder structs, the generic atomic modesetting code isn't able to
4448  * serialize non-blocking commits happening on the real DP connector of an MST topology switching
4449  * into/away from MST mode - as the CRTC on the real DP connector and the CRTCs on the connector's
4450  * MST topology will never share the same &drm_encoder.
4451  *
4452  * This function takes care of this serialization issue, by checking a root MST connector's atomic
4453  * state to determine if it is about to have a modeset - and then pulling in the MST topology state
4454  * if so, along with adding any relevant CRTCs to &drm_dp_mst_topology_state.pending_crtc_mask.
4455  *
4456  * Drivers implementing MST must call this function from the
4457  * &drm_connector_helper_funcs.atomic_check hook of any physical DP &drm_connector capable of
4458  * driving MST sinks.
4459  *
4460  * Returns:
4461  * 0 on success, negative error code otherwise
4462  */
4463 int drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state,
4464                                       struct drm_dp_mst_topology_mgr *mgr)
4465 {
4466         struct drm_atomic_state *state = new_conn_state->state;
4467         struct drm_connector_state *old_conn_state =
4468                 drm_atomic_get_old_connector_state(state, new_conn_state->connector);
4469         struct drm_crtc_state *crtc_state;
4470         struct drm_dp_mst_topology_state *mst_state = NULL;
4471
4472         if (new_conn_state->crtc) {
4473                 crtc_state = drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
4474                 if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
4475                         mst_state = drm_atomic_get_mst_topology_state(state, mgr);
4476                         if (IS_ERR(mst_state))
4477                                 return PTR_ERR(mst_state);
4478
4479                         mst_state->pending_crtc_mask |= drm_crtc_mask(new_conn_state->crtc);
4480                 }
4481         }
4482
4483         if (old_conn_state->crtc) {
4484                 crtc_state = drm_atomic_get_new_crtc_state(state, old_conn_state->crtc);
4485                 if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
4486                         if (!mst_state) {
4487                                 mst_state = drm_atomic_get_mst_topology_state(state, mgr);
4488                                 if (IS_ERR(mst_state))
4489                                         return PTR_ERR(mst_state);
4490                         }
4491
4492                         mst_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
4493                 }
4494         }
4495
4496         return 0;
4497 }
4498 EXPORT_SYMBOL(drm_dp_mst_root_conn_atomic_check);
4499
4500 /**
4501  * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
4502  * @mst_state: mst_state to update
4503  * @link_encoding_cap: the ecoding format on the link
4504  */
4505 void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap)
4506 {
4507         if (link_encoding_cap == DP_CAP_ANSI_128B132B) {
4508                 mst_state->total_avail_slots = 64;
4509                 mst_state->start_slot = 0;
4510         } else {
4511                 mst_state->total_avail_slots = 63;
4512                 mst_state->start_slot = 1;
4513         }
4514
4515         DRM_DEBUG_KMS("%s encoding format on mst_state 0x%p\n",
4516                       (link_encoding_cap == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b",
4517                       mst_state);
4518 }
4519 EXPORT_SYMBOL(drm_dp_mst_update_slots);
4520
4521 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4522                                      int id, u8 start_slot, u8 num_slots)
4523 {
4524         u8 payload_alloc[3], status;
4525         int ret;
4526         int retries = 0;
4527
4528         drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4529                            DP_PAYLOAD_TABLE_UPDATED);
4530
4531         payload_alloc[0] = id;
4532         payload_alloc[1] = start_slot;
4533         payload_alloc[2] = num_slots;
4534
4535         ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4536         if (ret != 3) {
4537                 drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret);
4538                 goto fail;
4539         }
4540
4541 retry:
4542         ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4543         if (ret < 0) {
4544                 drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret);
4545                 goto fail;
4546         }
4547
4548         if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4549                 retries++;
4550                 if (retries < 20) {
4551                         usleep_range(10000, 20000);
4552                         goto retry;
4553                 }
4554                 drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n",
4555                             status);
4556                 ret = -EINVAL;
4557                 goto fail;
4558         }
4559         ret = 0;
4560 fail:
4561         return ret;
4562 }
4563
4564 static int do_get_act_status(struct drm_dp_aux *aux)
4565 {
4566         int ret;
4567         u8 status;
4568
4569         ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4570         if (ret < 0)
4571                 return ret;
4572
4573         return status;
4574 }
4575
4576 /**
4577  * drm_dp_check_act_status() - Polls for ACT handled status.
4578  * @mgr: manager to use
4579  *
4580  * Tries waiting for the MST hub to finish updating it's payload table by
4581  * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4582  * take that long).
4583  *
4584  * Returns:
4585  * 0 if the ACT was handled in time, negative error code on failure.
4586  */
4587 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4588 {
4589         /*
4590          * There doesn't seem to be any recommended retry count or timeout in
4591          * the MST specification. Since some hubs have been observed to take
4592          * over 1 second to update their payload allocations under certain
4593          * conditions, we use a rather large timeout value.
4594          */
4595         const int timeout_ms = 3000;
4596         int ret, status;
4597
4598         ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4599                                  status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4600                                  200, timeout_ms * USEC_PER_MSEC);
4601         if (ret < 0 && status >= 0) {
4602                 drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
4603                         timeout_ms, status);
4604                 return -EINVAL;
4605         } else if (status < 0) {
4606                 /*
4607                  * Failure here isn't unexpected - the hub may have
4608                  * just been unplugged
4609                  */
4610                 drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
4611                 return status;
4612         }
4613
4614         return 0;
4615 }
4616 EXPORT_SYMBOL(drm_dp_check_act_status);
4617
4618 /**
4619  * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4620  * @clock: dot clock for the mode
4621  * @bpp: bpp for the mode.
4622  * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
4623  *
4624  * This uses the formula in the spec to calculate the PBN value for a mode.
4625  */
4626 int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
4627 {
4628         /*
4629          * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
4630          * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4631          * common multiplier to render an integer PBN for all link rate/lane
4632          * counts combinations
4633          * calculate
4634          * peak_kbps *= (1006/1000)
4635          * peak_kbps *= (64/54)
4636          * peak_kbps *= 8    convert to bytes
4637          *
4638          * If the bpp is in units of 1/16, further divide by 16. Put this
4639          * factor in the numerator rather than the denominator to avoid
4640          * integer overflow
4641          */
4642
4643         if (dsc)
4644                 return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006),
4645                                         8 * 54 * 1000 * 1000);
4646
4647         return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006),
4648                                 8 * 54 * 1000 * 1000);
4649 }
4650 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4651
4652 /* we want to kick the TX after we've ack the up/down IRQs. */
4653 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4654 {
4655         queue_work(system_long_wq, &mgr->tx_work);
4656 }
4657
4658 /*
4659  * Helper function for parsing DP device types into convenient strings
4660  * for use with dp_mst_topology
4661  */
4662 static const char *pdt_to_string(u8 pdt)
4663 {
4664         switch (pdt) {
4665         case DP_PEER_DEVICE_NONE:
4666                 return "NONE";
4667         case DP_PEER_DEVICE_SOURCE_OR_SST:
4668                 return "SOURCE OR SST";
4669         case DP_PEER_DEVICE_MST_BRANCHING:
4670                 return "MST BRANCHING";
4671         case DP_PEER_DEVICE_SST_SINK:
4672                 return "SST SINK";
4673         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4674                 return "DP LEGACY CONV";
4675         default:
4676                 return "ERR";
4677         }
4678 }
4679
4680 static void drm_dp_mst_dump_mstb(struct seq_file *m,
4681                                  struct drm_dp_mst_branch *mstb)
4682 {
4683         struct drm_dp_mst_port *port;
4684         int tabs = mstb->lct;
4685         char prefix[10];
4686         int i;
4687
4688         for (i = 0; i < tabs; i++)
4689                 prefix[i] = '\t';
4690         prefix[i] = '\0';
4691
4692         seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports);
4693         list_for_each_entry(port, &mstb->ports, next) {
4694                 seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n",
4695                            prefix,
4696                            port->port_num,
4697                            port,
4698                            port->input ? "input" : "output",
4699                            pdt_to_string(port->pdt),
4700                            port->ddps,
4701                            port->ldps,
4702                            port->num_sdp_streams,
4703                            port->num_sdp_stream_sinks,
4704                            port->fec_capable ? "true" : "false",
4705                            port->connector);
4706                 if (port->mstb)
4707                         drm_dp_mst_dump_mstb(m, port->mstb);
4708         }
4709 }
4710
4711 #define DP_PAYLOAD_TABLE_SIZE           64
4712
4713 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4714                                   char *buf)
4715 {
4716         int i;
4717
4718         for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4719                 if (drm_dp_dpcd_read(mgr->aux,
4720                                      DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4721                                      &buf[i], 16) != 16)
4722                         return false;
4723         }
4724         return true;
4725 }
4726
4727 static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4728                                struct drm_dp_mst_port *port, char *name,
4729                                int namelen)
4730 {
4731         struct edid *mst_edid;
4732
4733         mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4734         drm_edid_get_monitor_name(mst_edid, name, namelen);
4735         kfree(mst_edid);
4736 }
4737
4738 /**
4739  * drm_dp_mst_dump_topology(): dump topology to seq file.
4740  * @m: seq_file to dump output to
4741  * @mgr: manager to dump current topology for.
4742  *
4743  * helper to dump MST topology to a seq file for debugfs.
4744  */
4745 void drm_dp_mst_dump_topology(struct seq_file *m,
4746                               struct drm_dp_mst_topology_mgr *mgr)
4747 {
4748         struct drm_dp_mst_topology_state *state;
4749         struct drm_dp_mst_atomic_payload *payload;
4750         int i, ret;
4751
4752         mutex_lock(&mgr->lock);
4753         if (mgr->mst_primary)
4754                 drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4755
4756         /* dump VCPIs */
4757         mutex_unlock(&mgr->lock);
4758
4759         ret = drm_modeset_lock_single_interruptible(&mgr->base.lock);
4760         if (ret < 0)
4761                 return;
4762
4763         state = to_drm_dp_mst_topology_state(mgr->base.state);
4764         seq_printf(m, "\n*** Atomic state info ***\n");
4765         seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u, pbn_div: %d\n",
4766                    state->payload_mask, mgr->max_payloads, state->start_slot, state->pbn_div);
4767
4768         seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc |     sink name     |\n");
4769         for (i = 0; i < mgr->max_payloads; i++) {
4770                 list_for_each_entry(payload, &state->payloads, next) {
4771                         char name[14];
4772
4773                         if (payload->vcpi != i || payload->delete)
4774                                 continue;
4775
4776                         fetch_monitor_name(mgr, payload->port, name, sizeof(name));
4777                         seq_printf(m, " %5d %6d %6d %02d - %02d %5d %5s %19s\n",
4778                                    i,
4779                                    payload->port->port_num,
4780                                    payload->vcpi,
4781                                    payload->vc_start_slot,
4782                                    payload->vc_start_slot + payload->time_slots - 1,
4783                                    payload->pbn,
4784                                    payload->dsc_enabled ? "Y" : "N",
4785                                    (*name != 0) ? name : "Unknown");
4786                 }
4787         }
4788
4789         seq_printf(m, "\n*** DPCD Info ***\n");
4790         mutex_lock(&mgr->lock);
4791         if (mgr->mst_primary) {
4792                 u8 buf[DP_PAYLOAD_TABLE_SIZE];
4793                 int ret;
4794
4795                 if (drm_dp_read_dpcd_caps(mgr->aux, buf) < 0) {
4796                         seq_printf(m, "dpcd read failed\n");
4797                         goto out;
4798                 }
4799                 seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4800
4801                 ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4802                 if (ret != 2) {
4803                         seq_printf(m, "faux/mst read failed\n");
4804                         goto out;
4805                 }
4806                 seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4807
4808                 ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4809                 if (ret != 1) {
4810                         seq_printf(m, "mst ctrl read failed\n");
4811                         goto out;
4812                 }
4813                 seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4814
4815                 /* dump the standard OUI branch header */
4816                 ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4817                 if (ret != DP_BRANCH_OUI_HEADER_SIZE) {
4818                         seq_printf(m, "branch oui read failed\n");
4819                         goto out;
4820                 }
4821                 seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4822
4823                 for (i = 0x3; i < 0x8 && buf[i]; i++)
4824                         seq_printf(m, "%c", buf[i]);
4825                 seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4826                            buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4827                 if (dump_dp_payload_table(mgr, buf))
4828                         seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4829         }
4830
4831 out:
4832         mutex_unlock(&mgr->lock);
4833         drm_modeset_unlock(&mgr->base.lock);
4834 }
4835 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4836
4837 static void drm_dp_tx_work(struct work_struct *work)
4838 {
4839         struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4840
4841         mutex_lock(&mgr->qlock);
4842         if (!list_empty(&mgr->tx_msg_downq))
4843                 process_single_down_tx_qlock(mgr);
4844         mutex_unlock(&mgr->qlock);
4845 }
4846
4847 static inline void
4848 drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4849 {
4850         drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4851
4852         if (port->connector) {
4853                 drm_connector_unregister(port->connector);
4854                 drm_connector_put(port->connector);
4855         }
4856
4857         drm_dp_mst_put_port_malloc(port);
4858 }
4859
4860 static inline void
4861 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4862 {
4863         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4864         struct drm_dp_mst_port *port, *port_tmp;
4865         struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4866         bool wake_tx = false;
4867
4868         mutex_lock(&mgr->lock);
4869         list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4870                 list_del(&port->next);
4871                 drm_dp_mst_topology_put_port(port);
4872         }
4873         mutex_unlock(&mgr->lock);
4874
4875         /* drop any tx slot msg */
4876         mutex_lock(&mstb->mgr->qlock);
4877         list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
4878                 if (txmsg->dst != mstb)
4879                         continue;
4880
4881                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
4882                 list_del(&txmsg->next);
4883                 wake_tx = true;
4884         }
4885         mutex_unlock(&mstb->mgr->qlock);
4886
4887         if (wake_tx)
4888                 wake_up_all(&mstb->mgr->tx_waitq);
4889
4890         drm_dp_mst_put_mstb_malloc(mstb);
4891 }
4892
4893 static void drm_dp_delayed_destroy_work(struct work_struct *work)
4894 {
4895         struct drm_dp_mst_topology_mgr *mgr =
4896                 container_of(work, struct drm_dp_mst_topology_mgr,
4897                              delayed_destroy_work);
4898         bool send_hotplug = false, go_again;
4899
4900         /*
4901          * Not a regular list traverse as we have to drop the destroy
4902          * connector lock before destroying the mstb/port, to avoid AB->BA
4903          * ordering between this lock and the config mutex.
4904          */
4905         do {
4906                 go_again = false;
4907
4908                 for (;;) {
4909                         struct drm_dp_mst_branch *mstb;
4910
4911                         mutex_lock(&mgr->delayed_destroy_lock);
4912                         mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
4913                                                         struct drm_dp_mst_branch,
4914                                                         destroy_next);
4915                         if (mstb)
4916                                 list_del(&mstb->destroy_next);
4917                         mutex_unlock(&mgr->delayed_destroy_lock);
4918
4919                         if (!mstb)
4920                                 break;
4921
4922                         drm_dp_delayed_destroy_mstb(mstb);
4923                         go_again = true;
4924                 }
4925
4926                 for (;;) {
4927                         struct drm_dp_mst_port *port;
4928
4929                         mutex_lock(&mgr->delayed_destroy_lock);
4930                         port = list_first_entry_or_null(&mgr->destroy_port_list,
4931                                                         struct drm_dp_mst_port,
4932                                                         next);
4933                         if (port)
4934                                 list_del(&port->next);
4935                         mutex_unlock(&mgr->delayed_destroy_lock);
4936
4937                         if (!port)
4938                                 break;
4939
4940                         drm_dp_delayed_destroy_port(port);
4941                         send_hotplug = true;
4942                         go_again = true;
4943                 }
4944         } while (go_again);
4945
4946         if (send_hotplug)
4947                 drm_kms_helper_hotplug_event(mgr->dev);
4948 }
4949
4950 static struct drm_private_state *
4951 drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
4952 {
4953         struct drm_dp_mst_topology_state *state, *old_state =
4954                 to_dp_mst_topology_state(obj->state);
4955         struct drm_dp_mst_atomic_payload *pos, *payload;
4956
4957         state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
4958         if (!state)
4959                 return NULL;
4960
4961         __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
4962
4963         INIT_LIST_HEAD(&state->payloads);
4964         state->commit_deps = NULL;
4965         state->num_commit_deps = 0;
4966         state->pending_crtc_mask = 0;
4967
4968         list_for_each_entry(pos, &old_state->payloads, next) {
4969                 /* Prune leftover freed timeslot allocations */
4970                 if (pos->delete)
4971                         continue;
4972
4973                 payload = kmemdup(pos, sizeof(*payload), GFP_KERNEL);
4974                 if (!payload)
4975                         goto fail;
4976
4977                 drm_dp_mst_get_port_malloc(payload->port);
4978                 list_add(&payload->next, &state->payloads);
4979         }
4980
4981         return &state->base;
4982
4983 fail:
4984         list_for_each_entry_safe(pos, payload, &state->payloads, next) {
4985                 drm_dp_mst_put_port_malloc(pos->port);
4986                 kfree(pos);
4987         }
4988         kfree(state);
4989
4990         return NULL;
4991 }
4992
4993 static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
4994                                      struct drm_private_state *state)
4995 {
4996         struct drm_dp_mst_topology_state *mst_state =
4997                 to_dp_mst_topology_state(state);
4998         struct drm_dp_mst_atomic_payload *pos, *tmp;
4999         int i;
5000
5001         list_for_each_entry_safe(pos, tmp, &mst_state->payloads, next) {
5002                 /* We only keep references to ports with active payloads */
5003                 if (!pos->delete)
5004                         drm_dp_mst_put_port_malloc(pos->port);
5005                 kfree(pos);
5006         }
5007
5008         for (i = 0; i < mst_state->num_commit_deps; i++)
5009                 drm_crtc_commit_put(mst_state->commit_deps[i]);
5010
5011         kfree(mst_state->commit_deps);
5012         kfree(mst_state);
5013 }
5014
5015 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5016                                                  struct drm_dp_mst_branch *branch)
5017 {
5018         while (port->parent) {
5019                 if (port->parent == branch)
5020                         return true;
5021
5022                 if (port->parent->port_parent)
5023                         port = port->parent->port_parent;
5024                 else
5025                         break;
5026         }
5027         return false;
5028 }
5029
5030 static int
5031 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5032                                       struct drm_dp_mst_topology_state *state);
5033
5034 static int
5035 drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5036                                       struct drm_dp_mst_topology_state *state)
5037 {
5038         struct drm_dp_mst_atomic_payload *payload;
5039         struct drm_dp_mst_port *port;
5040         int pbn_used = 0, ret;
5041         bool found = false;
5042
5043         /* Check that we have at least one port in our state that's downstream
5044          * of this branch, otherwise we can skip this branch
5045          */
5046         list_for_each_entry(payload, &state->payloads, next) {
5047                 if (!payload->pbn ||
5048                     !drm_dp_mst_port_downstream_of_branch(payload->port, mstb))
5049                         continue;
5050
5051                 found = true;
5052                 break;
5053         }
5054         if (!found)
5055                 return 0;
5056
5057         if (mstb->port_parent)
5058                 drm_dbg_atomic(mstb->mgr->dev,
5059                                "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5060                                mstb->port_parent->parent, mstb->port_parent, mstb);
5061         else
5062                 drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
5063
5064         list_for_each_entry(port, &mstb->ports, next) {
5065                 ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
5066                 if (ret < 0)
5067                         return ret;
5068
5069                 pbn_used += ret;
5070         }
5071
5072         return pbn_used;
5073 }
5074
5075 static int
5076 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5077                                       struct drm_dp_mst_topology_state *state)
5078 {
5079         struct drm_dp_mst_atomic_payload *payload;
5080         int pbn_used = 0;
5081
5082         if (port->pdt == DP_PEER_DEVICE_NONE)
5083                 return 0;
5084
5085         if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5086                 payload = drm_atomic_get_mst_payload_state(state, port);
5087                 if (!payload)
5088                         return 0;
5089
5090                 /*
5091                  * This could happen if the sink deasserted its HPD line, but
5092                  * the branch device still reports it as attached (PDT != NONE).
5093                  */
5094                 if (!port->full_pbn) {
5095                         drm_dbg_atomic(port->mgr->dev,
5096                                        "[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
5097                                        port->parent, port);
5098                         return -EINVAL;
5099                 }
5100
5101                 pbn_used = payload->pbn;
5102         } else {
5103                 pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5104                                                                  state);
5105                 if (pbn_used <= 0)
5106                         return pbn_used;
5107         }
5108
5109         if (pbn_used > port->full_pbn) {
5110                 drm_dbg_atomic(port->mgr->dev,
5111                                "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5112                                port->parent, port, pbn_used, port->full_pbn);
5113                 return -ENOSPC;
5114         }
5115
5116         drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5117                        port->parent, port, pbn_used, port->full_pbn);
5118
5119         return pbn_used;
5120 }
5121
5122 static inline int
5123 drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr *mgr,
5124                                              struct drm_dp_mst_topology_state *mst_state)
5125 {
5126         struct drm_dp_mst_atomic_payload *payload;
5127         int avail_slots = mst_state->total_avail_slots, payload_count = 0;
5128
5129         list_for_each_entry(payload, &mst_state->payloads, next) {
5130                 /* Releasing payloads is always OK-even if the port is gone */
5131                 if (payload->delete) {
5132                         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all time slots\n",
5133                                        payload->port);
5134                         continue;
5135                 }
5136
5137                 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d time slots\n",
5138                                payload->port, payload->time_slots);
5139
5140                 avail_slots -= payload->time_slots;
5141                 if (avail_slots < 0) {
5142                         drm_dbg_atomic(mgr->dev,
5143                                        "[MST PORT:%p] not enough time slots in mst state %p (avail=%d)\n",
5144                                        payload->port, mst_state, avail_slots + payload->time_slots);
5145                         return -ENOSPC;
5146                 }
5147
5148                 if (++payload_count > mgr->max_payloads) {
5149                         drm_dbg_atomic(mgr->dev,
5150                                        "[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5151                                        mgr, mst_state, mgr->max_payloads);
5152                         return -EINVAL;
5153                 }
5154
5155                 /* Assign a VCPI */
5156                 if (!payload->vcpi) {
5157                         payload->vcpi = ffz(mst_state->payload_mask) + 1;
5158                         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] assigned VCPI #%d\n",
5159                                        payload->port, payload->vcpi);
5160                         mst_state->payload_mask |= BIT(payload->vcpi - 1);
5161                 }
5162         }
5163
5164         if (!payload_count)
5165                 mst_state->pbn_div = 0;
5166
5167         drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU pbn_div=%d avail=%d used=%d\n",
5168                        mgr, mst_state, mst_state->pbn_div, avail_slots,
5169                        mst_state->total_avail_slots - avail_slots);
5170
5171         return 0;
5172 }
5173
5174 /**
5175  * drm_dp_mst_add_affected_dsc_crtcs
5176  * @state: Pointer to the new struct drm_dp_mst_topology_state
5177  * @mgr: MST topology manager
5178  *
5179  * Whenever there is a change in mst topology
5180  * DSC configuration would have to be recalculated
5181  * therefore we need to trigger modeset on all affected
5182  * CRTCs in that topology
5183  *
5184  * See also:
5185  * drm_dp_mst_atomic_enable_dsc()
5186  */
5187 int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5188 {
5189         struct drm_dp_mst_topology_state *mst_state;
5190         struct drm_dp_mst_atomic_payload *pos;
5191         struct drm_connector *connector;
5192         struct drm_connector_state *conn_state;
5193         struct drm_crtc *crtc;
5194         struct drm_crtc_state *crtc_state;
5195
5196         mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5197
5198         if (IS_ERR(mst_state))
5199                 return PTR_ERR(mst_state);
5200
5201         list_for_each_entry(pos, &mst_state->payloads, next) {
5202
5203                 connector = pos->port->connector;
5204
5205                 if (!connector)
5206                         return -EINVAL;
5207
5208                 conn_state = drm_atomic_get_connector_state(state, connector);
5209
5210                 if (IS_ERR(conn_state))
5211                         return PTR_ERR(conn_state);
5212
5213                 crtc = conn_state->crtc;
5214
5215                 if (!crtc)
5216                         continue;
5217
5218                 if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5219                         continue;
5220
5221                 crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5222
5223                 if (IS_ERR(crtc_state))
5224                         return PTR_ERR(crtc_state);
5225
5226                 drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5227                                mgr, crtc);
5228
5229                 crtc_state->mode_changed = true;
5230         }
5231         return 0;
5232 }
5233 EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5234
5235 /**
5236  * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5237  * @state: Pointer to the new drm_atomic_state
5238  * @port: Pointer to the affected MST Port
5239  * @pbn: Newly recalculated bw required for link with DSC enabled
5240  * @enable: Boolean flag to enable or disable DSC on the port
5241  *
5242  * This function enables DSC on the given Port
5243  * by recalculating its vcpi from pbn provided
5244  * and sets dsc_enable flag to keep track of which
5245  * ports have DSC enabled
5246  *
5247  */
5248 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5249                                  struct drm_dp_mst_port *port,
5250                                  int pbn, bool enable)
5251 {
5252         struct drm_dp_mst_topology_state *mst_state;
5253         struct drm_dp_mst_atomic_payload *payload;
5254         int time_slots = 0;
5255
5256         mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5257         if (IS_ERR(mst_state))
5258                 return PTR_ERR(mst_state);
5259
5260         payload = drm_atomic_get_mst_payload_state(mst_state, port);
5261         if (!payload) {
5262                 drm_dbg_atomic(state->dev,
5263                                "[MST PORT:%p] Couldn't find payload in mst state %p\n",
5264                                port, mst_state);
5265                 return -EINVAL;
5266         }
5267
5268         if (payload->dsc_enabled == enable) {
5269                 drm_dbg_atomic(state->dev,
5270                                "[MST PORT:%p] DSC flag is already set to %d, returning %d time slots\n",
5271                                port, enable, payload->time_slots);
5272                 time_slots = payload->time_slots;
5273         }
5274
5275         if (enable) {
5276                 time_slots = drm_dp_atomic_find_time_slots(state, port->mgr, port, pbn);
5277                 drm_dbg_atomic(state->dev,
5278                                "[MST PORT:%p] Enabling DSC flag, reallocating %d time slots on the port\n",
5279                                port, time_slots);
5280                 if (time_slots < 0)
5281                         return -EINVAL;
5282         }
5283
5284         payload->dsc_enabled = enable;
5285
5286         return time_slots;
5287 }
5288 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5289
5290 /**
5291  * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5292  * atomic update is valid
5293  * @state: Pointer to the new &struct drm_dp_mst_topology_state
5294  *
5295  * Checks the given topology state for an atomic update to ensure that it's
5296  * valid. This includes checking whether there's enough bandwidth to support
5297  * the new timeslot allocations in the atomic update.
5298  *
5299  * Any atomic drivers supporting DP MST must make sure to call this after
5300  * checking the rest of their state in their
5301  * &drm_mode_config_funcs.atomic_check() callback.
5302  *
5303  * See also:
5304  * drm_dp_atomic_find_time_slots()
5305  * drm_dp_atomic_release_time_slots()
5306  *
5307  * Returns:
5308  *
5309  * 0 if the new state is valid, negative error code otherwise.
5310  */
5311 int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5312 {
5313         struct drm_dp_mst_topology_mgr *mgr;
5314         struct drm_dp_mst_topology_state *mst_state;
5315         int i, ret = 0;
5316
5317         for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5318                 if (!mgr->mst_state)
5319                         continue;
5320
5321                 ret = drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state);
5322                 if (ret)
5323                         break;
5324
5325                 mutex_lock(&mgr->lock);
5326                 ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5327                                                             mst_state);
5328                 mutex_unlock(&mgr->lock);
5329                 if (ret < 0)
5330                         break;
5331                 else
5332                         ret = 0;
5333         }
5334
5335         return ret;
5336 }
5337 EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5338
5339 const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5340         .atomic_duplicate_state = drm_dp_mst_duplicate_state,
5341         .atomic_destroy_state = drm_dp_mst_destroy_state,
5342 };
5343 EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5344
5345 /**
5346  * drm_atomic_get_mst_topology_state: get MST topology state
5347  * @state: global atomic state
5348  * @mgr: MST topology manager, also the private object in this case
5349  *
5350  * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5351  * state vtable so that the private object state returned is that of a MST
5352  * topology object.
5353  *
5354  * RETURNS:
5355  *
5356  * The MST topology state or error pointer.
5357  */
5358 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5359                                                                     struct drm_dp_mst_topology_mgr *mgr)
5360 {
5361         return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5362 }
5363 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5364
5365 /**
5366  * drm_atomic_get_new_mst_topology_state: get new MST topology state in atomic state, if any
5367  * @state: global atomic state
5368  * @mgr: MST topology manager, also the private object in this case
5369  *
5370  * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5371  * state vtable so that the private object state returned is that of a MST
5372  * topology object.
5373  *
5374  * Returns:
5375  *
5376  * The MST topology state, or NULL if there's no topology state for this MST mgr
5377  * in the global atomic state
5378  */
5379 struct drm_dp_mst_topology_state *
5380 drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state,
5381                                       struct drm_dp_mst_topology_mgr *mgr)
5382 {
5383         struct drm_private_state *priv_state =
5384                 drm_atomic_get_new_private_obj_state(state, &mgr->base);
5385
5386         return priv_state ? to_dp_mst_topology_state(priv_state) : NULL;
5387 }
5388 EXPORT_SYMBOL(drm_atomic_get_new_mst_topology_state);
5389
5390 /**
5391  * drm_dp_mst_topology_mgr_init - initialise a topology manager
5392  * @mgr: manager struct to initialise
5393  * @dev: device providing this structure - for i2c addition.
5394  * @aux: DP helper aux channel to talk to this device
5395  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5396  * @max_payloads: maximum number of payloads this GPU can source
5397  * @conn_base_id: the connector object ID the MST device is connected to.
5398  *
5399  * Return 0 for success, or negative error code on failure
5400  */
5401 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5402                                  struct drm_device *dev, struct drm_dp_aux *aux,
5403                                  int max_dpcd_transaction_bytes, int max_payloads,
5404                                  int conn_base_id)
5405 {
5406         struct drm_dp_mst_topology_state *mst_state;
5407
5408         mutex_init(&mgr->lock);
5409         mutex_init(&mgr->qlock);
5410         mutex_init(&mgr->delayed_destroy_lock);
5411         mutex_init(&mgr->up_req_lock);
5412         mutex_init(&mgr->probe_lock);
5413 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5414         mutex_init(&mgr->topology_ref_history_lock);
5415         stack_depot_init();
5416 #endif
5417         INIT_LIST_HEAD(&mgr->tx_msg_downq);
5418         INIT_LIST_HEAD(&mgr->destroy_port_list);
5419         INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5420         INIT_LIST_HEAD(&mgr->up_req_list);
5421
5422         /*
5423          * delayed_destroy_work will be queued on a dedicated WQ, so that any
5424          * requeuing will be also flushed when deiniting the topology manager.
5425          */
5426         mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5427         if (mgr->delayed_destroy_wq == NULL)
5428                 return -ENOMEM;
5429
5430         INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5431         INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5432         INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5433         INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5434         init_waitqueue_head(&mgr->tx_waitq);
5435         mgr->dev = dev;
5436         mgr->aux = aux;
5437         mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5438         mgr->max_payloads = max_payloads;
5439         mgr->conn_base_id = conn_base_id;
5440
5441         mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5442         if (mst_state == NULL)
5443                 return -ENOMEM;
5444
5445         mst_state->total_avail_slots = 63;
5446         mst_state->start_slot = 1;
5447
5448         mst_state->mgr = mgr;
5449         INIT_LIST_HEAD(&mst_state->payloads);
5450
5451         drm_atomic_private_obj_init(dev, &mgr->base,
5452                                     &mst_state->base,
5453                                     &drm_dp_mst_topology_state_funcs);
5454
5455         return 0;
5456 }
5457 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5458
5459 /**
5460  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5461  * @mgr: manager to destroy
5462  */
5463 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5464 {
5465         drm_dp_mst_topology_mgr_set_mst(mgr, false);
5466         flush_work(&mgr->work);
5467         /* The following will also drain any requeued work on the WQ. */
5468         if (mgr->delayed_destroy_wq) {
5469                 destroy_workqueue(mgr->delayed_destroy_wq);
5470                 mgr->delayed_destroy_wq = NULL;
5471         }
5472         mgr->dev = NULL;
5473         mgr->aux = NULL;
5474         drm_atomic_private_obj_fini(&mgr->base);
5475         mgr->funcs = NULL;
5476
5477         mutex_destroy(&mgr->delayed_destroy_lock);
5478         mutex_destroy(&mgr->qlock);
5479         mutex_destroy(&mgr->lock);
5480         mutex_destroy(&mgr->up_req_lock);
5481         mutex_destroy(&mgr->probe_lock);
5482 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5483         mutex_destroy(&mgr->topology_ref_history_lock);
5484 #endif
5485 }
5486 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5487
5488 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5489 {
5490         int i;
5491
5492         if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5493                 return false;
5494
5495         for (i = 0; i < num - 1; i++) {
5496                 if (msgs[i].flags & I2C_M_RD ||
5497                     msgs[i].len > 0xff)
5498                         return false;
5499         }
5500
5501         return msgs[num - 1].flags & I2C_M_RD &&
5502                 msgs[num - 1].len <= 0xff;
5503 }
5504
5505 static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5506 {
5507         int i;
5508
5509         for (i = 0; i < num - 1; i++) {
5510                 if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5511                     msgs[i].len > 0xff)
5512                         return false;
5513         }
5514
5515         return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5516 }
5517
5518 static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5519                                struct drm_dp_mst_port *port,
5520                                struct i2c_msg *msgs, int num)
5521 {
5522         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5523         unsigned int i;
5524         struct drm_dp_sideband_msg_req_body msg;
5525         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5526         int ret;
5527
5528         memset(&msg, 0, sizeof(msg));
5529         msg.req_type = DP_REMOTE_I2C_READ;
5530         msg.u.i2c_read.num_transactions = num - 1;
5531         msg.u.i2c_read.port_number = port->port_num;
5532         for (i = 0; i < num - 1; i++) {
5533                 msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5534                 msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5535                 msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5536                 msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5537         }
5538         msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5539         msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5540
5541         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5542         if (!txmsg) {
5543                 ret = -ENOMEM;
5544                 goto out;
5545         }
5546
5547         txmsg->dst = mstb;
5548         drm_dp_encode_sideband_req(&msg, txmsg);
5549
5550         drm_dp_queue_down_tx(mgr, txmsg);
5551
5552         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5553         if (ret > 0) {
5554
5555                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5556                         ret = -EREMOTEIO;
5557                         goto out;
5558                 }
5559                 if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5560                         ret = -EIO;
5561                         goto out;
5562                 }
5563                 memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5564                 ret = num;
5565         }
5566 out:
5567         kfree(txmsg);
5568         return ret;
5569 }
5570
5571 static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5572                                 struct drm_dp_mst_port *port,
5573                                 struct i2c_msg *msgs, int num)
5574 {
5575         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5576         unsigned int i;
5577         struct drm_dp_sideband_msg_req_body msg;
5578         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5579         int ret;
5580
5581         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5582         if (!txmsg) {
5583                 ret = -ENOMEM;
5584                 goto out;
5585         }
5586         for (i = 0; i < num; i++) {
5587                 memset(&msg, 0, sizeof(msg));
5588                 msg.req_type = DP_REMOTE_I2C_WRITE;
5589                 msg.u.i2c_write.port_number = port->port_num;
5590                 msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5591                 msg.u.i2c_write.num_bytes = msgs[i].len;
5592                 msg.u.i2c_write.bytes = msgs[i].buf;
5593
5594                 memset(txmsg, 0, sizeof(*txmsg));
5595                 txmsg->dst = mstb;
5596
5597                 drm_dp_encode_sideband_req(&msg, txmsg);
5598                 drm_dp_queue_down_tx(mgr, txmsg);
5599
5600                 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5601                 if (ret > 0) {
5602                         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5603                                 ret = -EREMOTEIO;
5604                                 goto out;
5605                         }
5606                 } else {
5607                         goto out;
5608                 }
5609         }
5610         ret = num;
5611 out:
5612         kfree(txmsg);
5613         return ret;
5614 }
5615
5616 /* I2C device */
5617 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5618                                struct i2c_msg *msgs, int num)
5619 {
5620         struct drm_dp_aux *aux = adapter->algo_data;
5621         struct drm_dp_mst_port *port =
5622                 container_of(aux, struct drm_dp_mst_port, aux);
5623         struct drm_dp_mst_branch *mstb;
5624         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5625         int ret;
5626
5627         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5628         if (!mstb)
5629                 return -EREMOTEIO;
5630
5631         if (remote_i2c_read_ok(msgs, num)) {
5632                 ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5633         } else if (remote_i2c_write_ok(msgs, num)) {
5634                 ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5635         } else {
5636                 drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n");
5637                 ret = -EIO;
5638         }
5639
5640         drm_dp_mst_topology_put_mstb(mstb);
5641         return ret;
5642 }
5643
5644 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5645 {
5646         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5647                I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5648                I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5649                I2C_FUNC_10BIT_ADDR;
5650 }
5651
5652 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5653         .functionality = drm_dp_mst_i2c_functionality,
5654         .master_xfer = drm_dp_mst_i2c_xfer,
5655 };
5656
5657 /**
5658  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5659  * @port: The port to add the I2C bus on
5660  *
5661  * Returns 0 on success or a negative error code on failure.
5662  */
5663 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5664 {
5665         struct drm_dp_aux *aux = &port->aux;
5666         struct device *parent_dev = port->mgr->dev->dev;
5667
5668         aux->ddc.algo = &drm_dp_mst_i2c_algo;
5669         aux->ddc.algo_data = aux;
5670         aux->ddc.retries = 3;
5671
5672         aux->ddc.class = I2C_CLASS_DDC;
5673         aux->ddc.owner = THIS_MODULE;
5674         /* FIXME: set the kdev of the port's connector as parent */
5675         aux->ddc.dev.parent = parent_dev;
5676         aux->ddc.dev.of_node = parent_dev->of_node;
5677
5678         strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5679                 sizeof(aux->ddc.name));
5680
5681         return i2c_add_adapter(&aux->ddc);
5682 }
5683
5684 /**
5685  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5686  * @port: The port to remove the I2C bus from
5687  */
5688 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5689 {
5690         i2c_del_adapter(&port->aux.ddc);
5691 }
5692
5693 /**
5694  * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5695  * @port: The port to check
5696  *
5697  * A single physical MST hub object can be represented in the topology
5698  * by multiple branches, with virtual ports between those branches.
5699  *
5700  * As of DP1.4, An MST hub with internal (virtual) ports must expose
5701  * certain DPCD registers over those ports. See sections 2.6.1.1.1
5702  * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5703  *
5704  * May acquire mgr->lock
5705  *
5706  * Returns:
5707  * true if the port is a virtual DP peer device, false otherwise
5708  */
5709 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5710 {
5711         struct drm_dp_mst_port *downstream_port;
5712
5713         if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5714                 return false;
5715
5716         /* Virtual DP Sink (Internal Display Panel) */
5717         if (port->port_num >= 8)
5718                 return true;
5719
5720         /* DP-to-HDMI Protocol Converter */
5721         if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5722             !port->mcs &&
5723             port->ldps)
5724                 return true;
5725
5726         /* DP-to-DP */
5727         mutex_lock(&port->mgr->lock);
5728         if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5729             port->mstb &&
5730             port->mstb->num_ports == 2) {
5731                 list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5732                         if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5733                             !downstream_port->input) {
5734                                 mutex_unlock(&port->mgr->lock);
5735                                 return true;
5736                         }
5737                 }
5738         }
5739         mutex_unlock(&port->mgr->lock);
5740
5741         return false;
5742 }
5743
5744 /**
5745  * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
5746  * @port: The port to check. A leaf of the MST tree with an attached display.
5747  *
5748  * Depending on the situation, DSC may be enabled via the endpoint aux,
5749  * the immediately upstream aux, or the connector's physical aux.
5750  *
5751  * This is both the correct aux to read DSC_CAPABILITY and the
5752  * correct aux to write DSC_ENABLED.
5753  *
5754  * This operation can be expensive (up to four aux reads), so
5755  * the caller should cache the return.
5756  *
5757  * Returns:
5758  * NULL if DSC cannot be enabled on this port, otherwise the aux device
5759  */
5760 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
5761 {
5762         struct drm_dp_mst_port *immediate_upstream_port;
5763         struct drm_dp_mst_port *fec_port;
5764         struct drm_dp_desc desc = {};
5765         u8 endpoint_fec;
5766         u8 endpoint_dsc;
5767
5768         if (!port)
5769                 return NULL;
5770
5771         if (port->parent->port_parent)
5772                 immediate_upstream_port = port->parent->port_parent;
5773         else
5774                 immediate_upstream_port = NULL;
5775
5776         fec_port = immediate_upstream_port;
5777         while (fec_port) {
5778                 /*
5779                  * Each physical link (i.e. not a virtual port) between the
5780                  * output and the primary device must support FEC
5781                  */
5782                 if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
5783                     !fec_port->fec_capable)
5784                         return NULL;
5785
5786                 fec_port = fec_port->parent->port_parent;
5787         }
5788
5789         /* DP-to-DP peer device */
5790         if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
5791                 u8 upstream_dsc;
5792
5793                 if (drm_dp_dpcd_read(&port->aux,
5794                                      DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5795                         return NULL;
5796                 if (drm_dp_dpcd_read(&port->aux,
5797                                      DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5798                         return NULL;
5799                 if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
5800                                      DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
5801                         return NULL;
5802
5803                 /* Enpoint decompression with DP-to-DP peer device */
5804                 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5805                     (endpoint_fec & DP_FEC_CAPABLE) &&
5806                     (upstream_dsc & DP_DSC_PASSTHROUGH_IS_SUPPORTED)) {
5807                         port->passthrough_aux = &immediate_upstream_port->aux;
5808                         return &port->aux;
5809                 }
5810
5811                 /* Virtual DPCD decompression with DP-to-DP peer device */
5812                 return &immediate_upstream_port->aux;
5813         }
5814
5815         /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
5816         if (drm_dp_mst_is_virtual_dpcd(port))
5817                 return &port->aux;
5818
5819         /*
5820          * Synaptics quirk
5821          * Applies to ports for which:
5822          * - Physical aux has Synaptics OUI
5823          * - DPv1.4 or higher
5824          * - Port is on primary branch device
5825          * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
5826          */
5827         if (drm_dp_read_desc(port->mgr->aux, &desc, true))
5828                 return NULL;
5829
5830         if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
5831             port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
5832             port->parent == port->mgr->mst_primary) {
5833                 u8 dpcd_ext[DP_RECEIVER_CAP_SIZE];
5834
5835                 if (drm_dp_read_dpcd_caps(port->mgr->aux, dpcd_ext) < 0)
5836                         return NULL;
5837
5838                 if ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) &&
5839                     ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK)
5840                      != DP_DWN_STRM_PORT_TYPE_ANALOG))
5841                         return port->mgr->aux;
5842         }
5843
5844         /*
5845          * The check below verifies if the MST sink
5846          * connected to the GPU is capable of DSC -
5847          * therefore the endpoint needs to be
5848          * both DSC and FEC capable.
5849          */
5850         if (drm_dp_dpcd_read(&port->aux,
5851            DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5852                 return NULL;
5853         if (drm_dp_dpcd_read(&port->aux,
5854            DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5855                 return NULL;
5856         if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5857            (endpoint_fec & DP_FEC_CAPABLE))
5858                 return &port->aux;
5859
5860         return NULL;
5861 }
5862 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);