drivers/dma/nbpfaxi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2013-2014 Renesas Electronics Europe Ltd.
   4  * Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
   5  */
   6
   7 #include <linux/bitmap.h>
   8 #include <linux/bitops.h>
   9 #include <linux/clk.h>
  10 #include <linux/dma-mapping.h>
  11 #include <linux/dmaengine.h>
  12 #include <linux/err.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/io.h>
  15 #include <linux/log2.h>
  16 #include <linux/module.h>
  17 #include <linux/of.h>
  18 #include <linux/of_device.h>
  19 #include <linux/of_dma.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/slab.h>
  22
  23 #include <dt-bindings/dma/nbpfaxi.h>
  24
  25 #include "dmaengine.h"
  26
  27 #define NBPF_REG_CHAN_OFFSET    0
  28 #define NBPF_REG_CHAN_SIZE      0x40
  29
  30 /* Channel Current Transaction Byte register */
  31 #define NBPF_CHAN_CUR_TR_BYTE   0x20
  32
  33 /* Channel Status register */
  34 #define NBPF_CHAN_STAT  0x24
  35 #define NBPF_CHAN_STAT_EN       1
  36 #define NBPF_CHAN_STAT_TACT     4
  37 #define NBPF_CHAN_STAT_ERR      0x10
  38 #define NBPF_CHAN_STAT_END      0x20
  39 #define NBPF_CHAN_STAT_TC       0x40
  40 #define NBPF_CHAN_STAT_DER      0x400
  41
  42 /* Channel Control register */
  43 #define NBPF_CHAN_CTRL  0x28
  44 #define NBPF_CHAN_CTRL_SETEN    1
  45 #define NBPF_CHAN_CTRL_CLREN    2
  46 #define NBPF_CHAN_CTRL_STG      4
  47 #define NBPF_CHAN_CTRL_SWRST    8
  48 #define NBPF_CHAN_CTRL_CLRRQ    0x10
  49 #define NBPF_CHAN_CTRL_CLREND   0x20
  50 #define NBPF_CHAN_CTRL_CLRTC    0x40
  51 #define NBPF_CHAN_CTRL_SETSUS   0x100
  52 #define NBPF_CHAN_CTRL_CLRSUS   0x200
  53
  54 /* Channel Configuration register */
  55 #define NBPF_CHAN_CFG   0x2c
  56 #define NBPF_CHAN_CFG_SEL       7               /* terminal SELect: 0..7 */
  57 #define NBPF_CHAN_CFG_REQD      8               /* REQuest Direction: DMAREQ is 0: input, 1: output */
  58 #define NBPF_CHAN_CFG_LOEN      0x10            /* LOw ENable: low DMA request line is: 0: inactive, 1: active */
  59 #define NBPF_CHAN_CFG_HIEN      0x20            /* HIgh ENable: high DMA request line is: 0: inactive, 1: active */
  60 #define NBPF_CHAN_CFG_LVL       0x40            /* LeVeL: DMA request line is sensed as 0: edge, 1: level */
  61 #define NBPF_CHAN_CFG_AM        0x700           /* ACK Mode: 0: Pulse mode, 1: Level mode, b'1x: Bus Cycle */
  62 #define NBPF_CHAN_CFG_SDS       0xf000          /* Source Data Size: 0: 8 bits,... , 7: 1024 bits */
  63 #define NBPF_CHAN_CFG_DDS       0xf0000         /* Destination Data Size: as above */
  64 #define NBPF_CHAN_CFG_SAD       0x100000        /* Source ADdress counting: 0: increment, 1: fixed */
  65 #define NBPF_CHAN_CFG_DAD       0x200000        /* Destination ADdress counting: 0: increment, 1: fixed */
  66 #define NBPF_CHAN_CFG_TM        0x400000        /* Transfer Mode: 0: single, 1: block TM */
  67 #define NBPF_CHAN_CFG_DEM       0x1000000       /* DMAEND interrupt Mask */
  68 #define NBPF_CHAN_CFG_TCM       0x2000000       /* DMATCO interrupt Mask */
  69 #define NBPF_CHAN_CFG_SBE       0x8000000       /* Sweep Buffer Enable */
  70 #define NBPF_CHAN_CFG_RSEL      0x10000000      /* RM: Register Set sELect */
  71 #define NBPF_CHAN_CFG_RSW       0x20000000      /* RM: Register Select sWitch */
  72 #define NBPF_CHAN_CFG_REN       0x40000000      /* RM: Register Set Enable */
  73 #define NBPF_CHAN_CFG_DMS       0x80000000      /* 0: register mode (RM), 1: link mode (LM) */
  74
  75 #define NBPF_CHAN_NXLA  0x38
  76 #define NBPF_CHAN_CRLA  0x3c
  77
  78 /* Link Header field */
  79 #define NBPF_HEADER_LV  1
  80 #define NBPF_HEADER_LE  2
  81 #define NBPF_HEADER_WBD 4
  82 #define NBPF_HEADER_DIM 8
  83
  84 #define NBPF_CTRL       0x300
  85 #define NBPF_CTRL_PR    1               /* 0: fixed priority, 1: round robin */
  86 #define NBPF_CTRL_LVINT 2               /* DMAEND and DMAERR signalling: 0: pulse, 1: level */
  87
  88 #define NBPF_DSTAT_ER   0x314
  89 #define NBPF_DSTAT_END  0x318
  90
  91 #define NBPF_DMA_BUSWIDTHS \
  92         (BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \
  93          BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
  94          BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
  95          BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
  96          BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
  97
  98 struct nbpf_config {
  99         int num_channels;
 100         int buffer_size;
 101 };
 102
 103 /*
 104  * We've got 3 types of objects, used to describe DMA transfers:
 105  * 1. high-level descriptor, containing a struct dma_async_tx_descriptor object
 106  *      in it, used to communicate with the user
 107  * 2. hardware DMA link descriptors, that we pass to DMAC for DMA transfer
 108  *      queuing, these must be DMAable, using either the streaming DMA API or
 109  *      allocated from coherent memory - one per SG segment
 110  * 3. one per SG segment descriptors, used to manage HW link descriptors from
 111  *      (2). They do not have to be DMAable. They can either be (a) allocated
 112  *      together with link descriptors as mixed (DMA / CPU) objects, or (b)
 113  *      separately. Even if allocated separately it would be best to link them
 114  *      to link descriptors once during channel resource allocation and always
 115  *      use them as a single object.
 116  * Therefore for both cases (a) and (b) at run-time objects (2) and (3) shall be
 117  * treated as a single SG segment descriptor.
 118  */
 119
 120 struct nbpf_link_reg {
 121         u32     header;
 122         u32     src_addr;
 123         u32     dst_addr;
 124         u32     transaction_size;
 125         u32     config;
 126         u32     interval;
 127         u32     extension;
 128         u32     next;
 129 } __packed;
 130
 131 struct nbpf_device;
 132 struct nbpf_channel;
 133 struct nbpf_desc;
 134
 135 struct nbpf_link_desc {
 136         struct nbpf_link_reg *hwdesc;
 137         dma_addr_t hwdesc_dma_addr;
 138         struct nbpf_desc *desc;
 139         struct list_head node;
 140 };
 141
 142 /**
 143  * struct nbpf_desc - DMA transfer descriptor
 144  * @async_tx:   dmaengine object
 145  * @user_wait:  waiting for a user ack
 146  * @length:     total transfer length
 147  * @sg:         list of hardware descriptors, represented by struct nbpf_link_desc
 148  * @node:       member in channel descriptor lists
 149  */
 150 struct nbpf_desc {
 151         struct dma_async_tx_descriptor async_tx;
 152         bool user_wait;
 153         size_t length;
 154         struct nbpf_channel *chan;
 155         struct list_head sg;
 156         struct list_head node;
 157 };
 158
 159 /* Take a wild guess: allocate 4 segments per descriptor */
 160 #define NBPF_SEGMENTS_PER_DESC 4
 161 #define NBPF_DESCS_PER_PAGE ((PAGE_SIZE - sizeof(struct list_head)) /   \
 162         (sizeof(struct nbpf_desc) +                                     \
 163          NBPF_SEGMENTS_PER_DESC *                                       \
 164          (sizeof(struct nbpf_link_desc) + sizeof(struct nbpf_link_reg))))
 165 #define NBPF_SEGMENTS_PER_PAGE (NBPF_SEGMENTS_PER_DESC * NBPF_DESCS_PER_PAGE)
 166
 167 struct nbpf_desc_page {
 168         struct list_head node;
 169         struct nbpf_desc desc[NBPF_DESCS_PER_PAGE];
 170         struct nbpf_link_desc ldesc[NBPF_SEGMENTS_PER_PAGE];
 171         struct nbpf_link_reg hwdesc[NBPF_SEGMENTS_PER_PAGE];
 172 };
 173
 174 /**
 175  * struct nbpf_channel - one DMAC channel
 176  * @dma_chan:   standard dmaengine channel object
 177  * @base:       register address base
 178  * @nbpf:       DMAC
 179  * @name:       IRQ name
 180  * @irq:        IRQ number
 181  * @slave_addr: address for slave DMA
 182  * @slave_width:slave data size in bytes
 183  * @slave_burst:maximum slave burst size in bytes
 184  * @terminal:   DMA terminal, assigned to this channel
 185  * @dmarq_cfg:  DMA request line configuration - high / low, edge / level for NBPF_CHAN_CFG
 186  * @flags:      configuration flags from DT
 187  * @lock:       protect descriptor lists
 188  * @free_links: list of free link descriptors
 189  * @free:       list of free descriptors
 190  * @queued:     list of queued descriptors
 191  * @active:     list of descriptors, scheduled for processing
 192  * @done:       list of completed descriptors, waiting post-processing
 193  * @desc_page:  list of additionally allocated descriptor pages - if any
 194  */
 195 struct nbpf_channel {
 196         struct dma_chan dma_chan;
 197         struct tasklet_struct tasklet;
 198         void __iomem *base;
 199         struct nbpf_device *nbpf;
 200         char name[16];
 201         int irq;
 202         dma_addr_t slave_src_addr;
 203         size_t slave_src_width;
 204         size_t slave_src_burst;
 205         dma_addr_t slave_dst_addr;
 206         size_t slave_dst_width;
 207         size_t slave_dst_burst;
 208         unsigned int terminal;
 209         u32 dmarq_cfg;
 210         unsigned long flags;
 211         spinlock_t lock;
 212         struct list_head free_links;
 213         struct list_head free;
 214         struct list_head queued;
 215         struct list_head active;
 216         struct list_head done;
 217         struct list_head desc_page;
 218         struct nbpf_desc *running;
 219         bool paused;
 220 };
 221
 222 struct nbpf_device {
 223         struct dma_device dma_dev;
 224         void __iomem *base;
 225         u32 max_burst_mem_read;
 226         u32 max_burst_mem_write;
 227         struct clk *clk;
 228         const struct nbpf_config *config;
 229         unsigned int eirq;
 230         struct nbpf_channel chan[];
 231 };
 232
 233 enum nbpf_model {
 234         NBPF1B4,
 235         NBPF1B8,
 236         NBPF1B16,
 237         NBPF4B4,
 238         NBPF4B8,
 239         NBPF4B16,
 240         NBPF8B4,
 241         NBPF8B8,
 242         NBPF8B16,
 243 };
 244
 245 static struct nbpf_config nbpf_cfg[] = {
 246         [NBPF1B4] = {
 247                 .num_channels = 1,
 248                 .buffer_size = 4,
 249         },
 250         [NBPF1B8] = {
 251                 .num_channels = 1,
 252                 .buffer_size = 8,
 253         },
 254         [NBPF1B16] = {
 255                 .num_channels = 1,
 256                 .buffer_size = 16,
 257         },
 258         [NBPF4B4] = {
 259                 .num_channels = 4,
 260                 .buffer_size = 4,
 261         },
 262         [NBPF4B8] = {
 263                 .num_channels = 4,
 264                 .buffer_size = 8,
 265         },
 266         [NBPF4B16] = {
 267                 .num_channels = 4,
 268                 .buffer_size = 16,
 269         },
 270         [NBPF8B4] = {
 271                 .num_channels = 8,
 272                 .buffer_size = 4,
 273         },
 274         [NBPF8B8] = {
 275                 .num_channels = 8,
 276                 .buffer_size = 8,
 277         },
 278         [NBPF8B16] = {
 279                 .num_channels = 8,
 280                 .buffer_size = 16,
 281         },
 282 };
 283
 284 #define nbpf_to_chan(d) container_of(d, struct nbpf_channel, dma_chan)
 285
 286 /*
 287  * dmaengine drivers seem to have a lot in common and instead of sharing more
 288  * code, they reimplement those common algorithms independently. In this driver
 289  * we try to separate the hardware-specific part from the (largely) generic
 290  * part. This improves code readability and makes it possible in the future to
 291  * reuse the generic code in form of a helper library. That generic code should
 292  * be suitable for various DMA controllers, using transfer descriptors in RAM
 293  * and pushing one SG list at a time to the DMA controller.
 294  */
 295
 296 /*              Hardware-specific part          */
 297
 298 static inline u32 nbpf_chan_read(struct nbpf_channel *chan,
 299                                  unsigned int offset)
 300 {
 301         u32 data = ioread32(chan->base + offset);
 302         dev_dbg(chan->dma_chan.device->dev, "%s(0x%p + 0x%x) = 0x%x\n",
 303                 __func__, chan->base, offset, data);
 304         return data;
 305 }
 306
 307 static inline void nbpf_chan_write(struct nbpf_channel *chan,
 308                                    unsigned int offset, u32 data)
 309 {
 310         iowrite32(data, chan->base + offset);
 311         dev_dbg(chan->dma_chan.device->dev, "%s(0x%p + 0x%x) = 0x%x\n",
 312                 __func__, chan->base, offset, data);
 313 }
 314
 315 static inline u32 nbpf_read(struct nbpf_device *nbpf,
 316                             unsigned int offset)
 317 {
 318         u32 data = ioread32(nbpf->base + offset);
 319         dev_dbg(nbpf->dma_dev.dev, "%s(0x%p + 0x%x) = 0x%x\n",
 320                 __func__, nbpf->base, offset, data);
 321         return data;
 322 }
 323
 324 static inline void nbpf_write(struct nbpf_device *nbpf,
 325                               unsigned int offset, u32 data)
 326 {
 327         iowrite32(data, nbpf->base + offset);
 328         dev_dbg(nbpf->dma_dev.dev, "%s(0x%p + 0x%x) = 0x%x\n",
 329                 __func__, nbpf->base, offset, data);
 330 }
 331
 332 static void nbpf_chan_halt(struct nbpf_channel *chan)
 333 {
 334         nbpf_chan_write(chan, NBPF_CHAN_CTRL, NBPF_CHAN_CTRL_CLREN);
 335 }
 336
 337 static bool nbpf_status_get(struct nbpf_channel *chan)
 338 {
 339         u32 status = nbpf_read(chan->nbpf, NBPF_DSTAT_END);
 340
 341         return status & BIT(chan - chan->nbpf->chan);
 342 }
 343
 344 static void nbpf_status_ack(struct nbpf_channel *chan)
 345 {
 346         nbpf_chan_write(chan, NBPF_CHAN_CTRL, NBPF_CHAN_CTRL_CLREND);
 347 }
 348
 349 static u32 nbpf_error_get(struct nbpf_device *nbpf)
 350 {
 351         return nbpf_read(nbpf, NBPF_DSTAT_ER);
 352 }
 353
 354 static struct nbpf_channel *nbpf_error_get_channel(struct nbpf_device *nbpf, u32 error)
 355 {
 356         return nbpf->chan + __ffs(error);
 357 }
 358
 359 static void nbpf_error_clear(struct nbpf_channel *chan)
 360 {
 361         u32 status;
 362         int i;
 363
 364         /* Stop the channel, make sure DMA has been aborted */
 365         nbpf_chan_halt(chan);
 366
 367         for (i = 1000; i; i--) {
 368                 status = nbpf_chan_read(chan, NBPF_CHAN_STAT);
 369                 if (!(status & NBPF_CHAN_STAT_TACT))
 370                         break;
 371                 cpu_relax();
 372         }
 373
 374         if (!i)
 375                 dev_err(chan->dma_chan.device->dev,
 376                         "%s(): abort timeout, channel status 0x%x\n", __func__, status);
 377
 378         nbpf_chan_write(chan, NBPF_CHAN_CTRL, NBPF_CHAN_CTRL_SWRST);
 379 }
 380
 381 static int nbpf_start(struct nbpf_desc *desc)
 382 {
 383         struct nbpf_channel *chan = desc->chan;
 384         struct nbpf_link_desc *ldesc = list_first_entry(&desc->sg, struct nbpf_link_desc, node);
 385
 386         nbpf_chan_write(chan, NBPF_CHAN_NXLA, (u32)ldesc->hwdesc_dma_addr);
 387         nbpf_chan_write(chan, NBPF_CHAN_CTRL, NBPF_CHAN_CTRL_SETEN | NBPF_CHAN_CTRL_CLRSUS);
 388         chan->paused = false;
 389
 390         /* Software trigger MEMCPY - only MEMCPY uses the block mode */
 391         if (ldesc->hwdesc->config & NBPF_CHAN_CFG_TM)
 392                 nbpf_chan_write(chan, NBPF_CHAN_CTRL, NBPF_CHAN_CTRL_STG);
 393
 394         dev_dbg(chan->nbpf->dma_dev.dev, "%s(): next 0x%x, cur 0x%x\n", __func__,
 395                 nbpf_chan_read(chan, NBPF_CHAN_NXLA), nbpf_chan_read(chan, NBPF_CHAN_CRLA));
 396
 397         return 0;
 398 }
 399
 400 static void nbpf_chan_prepare(struct nbpf_channel *chan)
 401 {
 402         chan->dmarq_cfg = (chan->flags & NBPF_SLAVE_RQ_HIGH ? NBPF_CHAN_CFG_HIEN : 0) |
 403                 (chan->flags & NBPF_SLAVE_RQ_LOW ? NBPF_CHAN_CFG_LOEN : 0) |
 404                 (chan->flags & NBPF_SLAVE_RQ_LEVEL ?
 405                  NBPF_CHAN_CFG_LVL | (NBPF_CHAN_CFG_AM & 0x200) : 0) |
 406                 chan->terminal;
 407 }
 408
 409 static void nbpf_chan_prepare_default(struct nbpf_channel *chan)
 410 {
 411         /* Don't output DMAACK */
 412         chan->dmarq_cfg = NBPF_CHAN_CFG_AM & 0x400;
 413         chan->terminal = 0;
 414         chan->flags = 0;
 415 }
 416
 417 static void nbpf_chan_configure(struct nbpf_channel *chan)
 418 {
 419         /*
 420          * We assume, that only the link mode and DMA request line configuration
 421          * have to be set in the configuration register manually. Dynamic
 422          * per-transfer configuration will be loaded from transfer descriptors.
 423          */
 424         nbpf_chan_write(chan, NBPF_CHAN_CFG, NBPF_CHAN_CFG_DMS | chan->dmarq_cfg);
 425 }
 426
 427 static u32 nbpf_xfer_ds(struct nbpf_device *nbpf, size_t size,
 428                         enum dma_transfer_direction direction)
 429 {
 430         int max_burst = nbpf->config->buffer_size * 8;
 431
 432         if (nbpf->max_burst_mem_read || nbpf->max_burst_mem_write) {
 433                 switch (direction) {
 434                 case DMA_MEM_TO_MEM:
 435                         max_burst = min_not_zero(nbpf->max_burst_mem_read,
 436                                                  nbpf->max_burst_mem_write);
 437                         break;
 438                 case DMA_MEM_TO_DEV:
 439                         if (nbpf->max_burst_mem_read)
 440                                 max_burst = nbpf->max_burst_mem_read;
 441                         break;
 442                 case DMA_DEV_TO_MEM:
 443                         if (nbpf->max_burst_mem_write)
 444                                 max_burst = nbpf->max_burst_mem_write;
 445                         break;
 446                 case DMA_DEV_TO_DEV:
 447                 default:
 448                         break;
 449                 }
 450         }
 451
 452         /* Maximum supported bursts depend on the buffer size */
 453         return min_t(int, __ffs(size), ilog2(max_burst));
 454 }
 455
 456 static size_t nbpf_xfer_size(struct nbpf_device *nbpf,
 457                              enum dma_slave_buswidth width, u32 burst)
 458 {
 459         size_t size;
 460
 461         if (!burst)
 462                 burst = 1;
 463
 464         switch (width) {
 465         case DMA_SLAVE_BUSWIDTH_8_BYTES:
 466                 size = 8 * burst;
 467                 break;
 468
 469         case DMA_SLAVE_BUSWIDTH_4_BYTES:
 470                 size = 4 * burst;
 471                 break;
 472
 473         case DMA_SLAVE_BUSWIDTH_2_BYTES:
 474                 size = 2 * burst;
 475                 break;
 476
 477         default:
 478                 pr_warn("%s(): invalid bus width %u\n", __func__, width);
 479                 /* fall through */
 480         case DMA_SLAVE_BUSWIDTH_1_BYTE:
 481                 size = burst;
 482         }
 483
 484         return nbpf_xfer_ds(nbpf, size, DMA_TRANS_NONE);
 485 }
 486
 487 /*
 488  * We need a way to recognise slaves, whose data is sent "raw" over the bus,
 489  * i.e. it isn't known in advance how many bytes will be received. Therefore
 490  * the slave driver has to provide a "large enough" buffer and either read the
 491  * buffer, when it is full, or detect, that some data has arrived, then wait for
 492  * a timeout, if no more data arrives - receive what's already there. We want to
 493  * handle such slaves in a special way to allow an optimised mode for other
 494  * users, for whom the amount of data is known in advance. So far there's no way
 495  * to recognise such slaves. We use a data-width check to distinguish between
 496  * the SD host and the PL011 UART.
 497  */
 498
 499 static int nbpf_prep_one(struct nbpf_link_desc *ldesc,
 500                          enum dma_transfer_direction direction,
 501                          dma_addr_t src, dma_addr_t dst, size_t size, bool last)
 502 {
 503         struct nbpf_link_reg *hwdesc = ldesc->hwdesc;
 504         struct nbpf_desc *desc = ldesc->desc;
 505         struct nbpf_channel *chan = desc->chan;
 506         struct device *dev = chan->dma_chan.device->dev;
 507         size_t mem_xfer, slave_xfer;
 508         bool can_burst;
 509
 510         hwdesc->header = NBPF_HEADER_WBD | NBPF_HEADER_LV |
 511                 (last ? NBPF_HEADER_LE : 0);
 512
 513         hwdesc->src_addr = src;
 514         hwdesc->dst_addr = dst;
 515         hwdesc->transaction_size = size;
 516
 517         /*
 518          * set config: SAD, DAD, DDS, SDS, etc.
 519          * Note on transfer sizes: the DMAC can perform unaligned DMA transfers,
 520          * but it is important to have transaction size a multiple of both
 521          * receiver and transmitter transfer sizes. It is also possible to use
 522          * different RAM and device transfer sizes, and it does work well with
 523          * some devices, e.g. with V08R07S01E SD host controllers, which can use
 524          * 128 byte transfers. But this doesn't work with other devices,
 525          * especially when the transaction size is unknown. This is the case,
 526          * e.g. with serial drivers like amba-pl011.c. For reception it sets up
 527          * the transaction size of 4K and if fewer bytes are received, it
 528          * pauses DMA and reads out data received via DMA as well as those left
 529          * in the Rx FIFO. For this to work with the RAM side using burst
 530          * transfers we enable the SBE bit and terminate the transfer in our
 531          * .device_pause handler.
 532          */
 533         mem_xfer = nbpf_xfer_ds(chan->nbpf, size, direction);
 534
 535         switch (direction) {
 536         case DMA_DEV_TO_MEM:
 537                 can_burst = chan->slave_src_width >= 3;
 538                 slave_xfer = min(mem_xfer, can_burst ?
 539                                  chan->slave_src_burst : chan->slave_src_width);
 540                 /*
 541                  * Is the slave narrower than 64 bits, i.e. isn't using the full
 542                  * bus width and cannot use bursts?
 543                  */
 544                 if (mem_xfer > chan->slave_src_burst && !can_burst)
 545                         mem_xfer = chan->slave_src_burst;
 546                 /* Device-to-RAM DMA is unreliable without REQD set */
 547                 hwdesc->config = NBPF_CHAN_CFG_SAD | (NBPF_CHAN_CFG_DDS & (mem_xfer << 16)) |
 548                         (NBPF_CHAN_CFG_SDS & (slave_xfer << 12)) | NBPF_CHAN_CFG_REQD |
 549                         NBPF_CHAN_CFG_SBE;
 550                 break;
 551
 552         case DMA_MEM_TO_DEV:
 553                 slave_xfer = min(mem_xfer, chan->slave_dst_width >= 3 ?
 554                                  chan->slave_dst_burst : chan->slave_dst_width);
 555                 hwdesc->config = NBPF_CHAN_CFG_DAD | (NBPF_CHAN_CFG_SDS & (mem_xfer << 12)) |
 556                         (NBPF_CHAN_CFG_DDS & (slave_xfer << 16)) | NBPF_CHAN_CFG_REQD;
 557                 break;
 558
 559         case DMA_MEM_TO_MEM:
 560                 hwdesc->config = NBPF_CHAN_CFG_TCM | NBPF_CHAN_CFG_TM |
 561                         (NBPF_CHAN_CFG_SDS & (mem_xfer << 12)) |
 562                         (NBPF_CHAN_CFG_DDS & (mem_xfer << 16));
 563                 break;
 564
 565         default:
 566                 return -EINVAL;
 567         }
 568
 569         hwdesc->config |= chan->dmarq_cfg | (last ? 0 : NBPF_CHAN_CFG_DEM) |
 570                 NBPF_CHAN_CFG_DMS;
 571
 572         dev_dbg(dev, "%s(): desc @ %pad: hdr 0x%x, cfg 0x%x, %zu @ %pad -> %pad\n",
 573                 __func__, &ldesc->hwdesc_dma_addr, hwdesc->header,
 574                 hwdesc->config, size, &src, &dst);
 575
 576         dma_sync_single_for_device(dev, ldesc->hwdesc_dma_addr, sizeof(*hwdesc),
 577                                    DMA_TO_DEVICE);
 578
 579         return 0;
 580 }
 581
 582 static size_t nbpf_bytes_left(struct nbpf_channel *chan)
 583 {
 584         return nbpf_chan_read(chan, NBPF_CHAN_CUR_TR_BYTE);
 585 }
 586
 587 static void nbpf_configure(struct nbpf_device *nbpf)
 588 {
 589         nbpf_write(nbpf, NBPF_CTRL, NBPF_CTRL_LVINT);
 590 }
 591
 592 /*              Generic part                    */
 593
 594 /* DMA ENGINE functions */
 595 static void nbpf_issue_pending(struct dma_chan *dchan)
 596 {
 597         struct nbpf_channel *chan = nbpf_to_chan(dchan);
 598         unsigned long flags;
 599
 600         dev_dbg(dchan->device->dev, "Entry %s()\n", __func__);
 601
 602         spin_lock_irqsave(&chan->lock, flags);
 603         if (list_empty(&chan->queued))
 604                 goto unlock;
 605
 606         list_splice_tail_init(&chan->queued, &chan->active);
 607
 608         if (!chan->running) {
 609                 struct nbpf_desc *desc = list_first_entry(&chan->active,
 610                                                 struct nbpf_desc, node);
 611                 if (!nbpf_start(desc))
 612                         chan->running = desc;
 613         }
 614
 615 unlock:
 616         spin_unlock_irqrestore(&chan->lock, flags);
 617 }
 618
 619 static enum dma_status nbpf_tx_status(struct dma_chan *dchan,
 620                 dma_cookie_t cookie, struct dma_tx_state *state)
 621 {
 622         struct nbpf_channel *chan = nbpf_to_chan(dchan);
 623         enum dma_status status = dma_cookie_status(dchan, cookie, state);
 624
 625         if (state) {
 626                 dma_cookie_t running;
 627                 unsigned long flags;
 628
 629                 spin_lock_irqsave(&chan->lock, flags);
 630                 running = chan->running ? chan->running->async_tx.cookie : -EINVAL;
 631
 632                 if (cookie == running) {
 633                         state->residue = nbpf_bytes_left(chan);
 634                         dev_dbg(dchan->device->dev, "%s(): residue %u\n", __func__,
 635                                 state->residue);
 636                 } else if (status == DMA_IN_PROGRESS) {
 637                         struct nbpf_desc *desc;
 638                         bool found = false;
 639
 640                         list_for_each_entry(desc, &chan->active, node)
 641                                 if (desc->async_tx.cookie == cookie) {
 642                                         found = true;
 643                                         break;
 644                                 }
 645
 646                         if (!found)
 647                                 list_for_each_entry(desc, &chan->queued, node)
 648                                         if (desc->async_tx.cookie == cookie) {
 649                                                 found = true;
 650                                                 break;
 651
 652                                         }
 653
 654                         state->residue = found ? desc->length : 0;
 655                 }
 656
 657                 spin_unlock_irqrestore(&chan->lock, flags);
 658         }
 659
 660         if (chan->paused)
 661                 status = DMA_PAUSED;
 662
 663         return status;
 664 }
 665
 666 static dma_cookie_t nbpf_tx_submit(struct dma_async_tx_descriptor *tx)
 667 {
 668         struct nbpf_desc *desc = container_of(tx, struct nbpf_desc, async_tx);
 669         struct nbpf_channel *chan = desc->chan;
 670         unsigned long flags;
 671         dma_cookie_t cookie;
 672
 673         spin_lock_irqsave(&chan->lock, flags);
 674         cookie = dma_cookie_assign(tx);
 675         list_add_tail(&desc->node, &chan->queued);
 676         spin_unlock_irqrestore(&chan->lock, flags);
 677
 678         dev_dbg(chan->dma_chan.device->dev, "Entry %s(%d)\n", __func__, cookie);
 679
 680         return cookie;
 681 }
 682
 683 static int nbpf_desc_page_alloc(struct nbpf_channel *chan)
 684 {
 685         struct dma_chan *dchan = &chan->dma_chan;
 686         struct nbpf_desc_page *dpage = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 687         struct nbpf_link_desc *ldesc;
 688         struct nbpf_link_reg *hwdesc;
 689         struct nbpf_desc *desc;
 690         LIST_HEAD(head);
 691         LIST_HEAD(lhead);
 692         int i;
 693         struct device *dev = dchan->device->dev;
 694
 695         if (!dpage)
 696                 return -ENOMEM;
 697
 698         dev_dbg(dev, "%s(): alloc %lu descriptors, %lu segments, total alloc %zu\n",
 699                 __func__, NBPF_DESCS_PER_PAGE, NBPF_SEGMENTS_PER_PAGE, sizeof(*dpage));
 700
 701         for (i = 0, ldesc = dpage->ldesc, hwdesc = dpage->hwdesc;
 702              i < ARRAY_SIZE(dpage->ldesc);
 703              i++, ldesc++, hwdesc++) {
 704                 ldesc->hwdesc = hwdesc;
 705                 list_add_tail(&ldesc->node, &lhead);
 706                 ldesc->hwdesc_dma_addr = dma_map_single(dchan->device->dev,
 707                                         hwdesc, sizeof(*hwdesc), DMA_TO_DEVICE);
 708
 709                 dev_dbg(dev, "%s(): mapped 0x%p to %pad\n", __func__,
 710                         hwdesc, &ldesc->hwdesc_dma_addr);
 711         }
 712
 713         for (i = 0, desc = dpage->desc;
 714              i < ARRAY_SIZE(dpage->desc);
 715              i++, desc++) {
 716                 dma_async_tx_descriptor_init(&desc->async_tx, dchan);
 717                 desc->async_tx.tx_submit = nbpf_tx_submit;
 718                 desc->chan = chan;
 719                 INIT_LIST_HEAD(&desc->sg);
 720                 list_add_tail(&desc->node, &head);
 721         }
 722
 723         /*
 724          * This function cannot be called from interrupt context, so, no need to
 725          * save flags
 726          */
 727         spin_lock_irq(&chan->lock);
 728         list_splice_tail(&lhead, &chan->free_links);
 729         list_splice_tail(&head, &chan->free);
 730         list_add(&dpage->node, &chan->desc_page);
 731         spin_unlock_irq(&chan->lock);
 732
 733         return ARRAY_SIZE(dpage->desc);
 734 }
 735
 736 static void nbpf_desc_put(struct nbpf_desc *desc)
 737 {
 738         struct nbpf_channel *chan = desc->chan;
 739         struct nbpf_link_desc *ldesc, *tmp;
 740         unsigned long flags;
 741
 742         spin_lock_irqsave(&chan->lock, flags);
 743         list_for_each_entry_safe(ldesc, tmp, &desc->sg, node)
 744                 list_move(&ldesc->node, &chan->free_links);
 745
 746         list_add(&desc->node, &chan->free);
 747         spin_unlock_irqrestore(&chan->lock, flags);
 748 }
 749
 750 static void nbpf_scan_acked(struct nbpf_channel *chan)
 751 {
 752         struct nbpf_desc *desc, *tmp;
 753         unsigned long flags;
 754         LIST_HEAD(head);
 755
 756         spin_lock_irqsave(&chan->lock, flags);
 757         list_for_each_entry_safe(desc, tmp, &chan->done, node)
 758                 if (async_tx_test_ack(&desc->async_tx) && desc->user_wait) {
 759                         list_move(&desc->node, &head);
 760                         desc->user_wait = false;
 761                 }
 762         spin_unlock_irqrestore(&chan->lock, flags);
 763
 764         list_for_each_entry_safe(desc, tmp, &head, node) {
 765                 list_del(&desc->node);
 766                 nbpf_desc_put(desc);
 767         }
 768 }
 769
 770 /*
 771  * We have to allocate descriptors with the channel lock dropped. This means,
 772  * before we re-acquire the lock buffers can be taken already, so we have to
 773  * re-check after re-acquiring the lock and possibly retry, if buffers are gone
 774  * again.
 775  */
 776 static struct nbpf_desc *nbpf_desc_get(struct nbpf_channel *chan, size_t len)
 777 {
 778         struct nbpf_desc *desc = NULL;
 779         struct nbpf_link_desc *ldesc, *prev = NULL;
 780
 781         nbpf_scan_acked(chan);
 782
 783         spin_lock_irq(&chan->lock);
 784
 785         do {
 786                 int i = 0, ret;
 787
 788                 if (list_empty(&chan->free)) {
 789                         /* No more free descriptors */
 790                         spin_unlock_irq(&chan->lock);
 791                         ret = nbpf_desc_page_alloc(chan);
 792                         if (ret < 0)
 793                                 return NULL;
 794                         spin_lock_irq(&chan->lock);
 795                         continue;
 796                 }
 797                 desc = list_first_entry(&chan->free, struct nbpf_desc, node);
 798                 list_del(&desc->node);
 799
 800                 do {
 801                         if (list_empty(&chan->free_links)) {
 802                                 /* No more free link descriptors */
 803                                 spin_unlock_irq(&chan->lock);
 804                                 ret = nbpf_desc_page_alloc(chan);
 805                                 if (ret < 0) {
 806                                         nbpf_desc_put(desc);
 807                                         return NULL;
 808                                 }
 809                                 spin_lock_irq(&chan->lock);
 810                                 continue;
 811                         }
 812
 813                         ldesc = list_first_entry(&chan->free_links,
 814                                                  struct nbpf_link_desc, node);
 815                         ldesc->desc = desc;
 816                         if (prev)
 817                                 prev->hwdesc->next = (u32)ldesc->hwdesc_dma_addr;
 818
 819                         prev = ldesc;
 820                         list_move_tail(&ldesc->node, &desc->sg);
 821
 822                         i++;
 823                 } while (i < len);
 824         } while (!desc);
 825
 826         prev->hwdesc->next = 0;
 827
 828         spin_unlock_irq(&chan->lock);
 829
 830         return desc;
 831 }
 832
 833 static void nbpf_chan_idle(struct nbpf_channel *chan)
 834 {
 835         struct nbpf_desc *desc, *tmp;
 836         unsigned long flags;
 837         LIST_HEAD(head);
 838
 839         spin_lock_irqsave(&chan->lock, flags);
 840
 841         list_splice_init(&chan->done, &head);
 842         list_splice_init(&chan->active, &head);
 843         list_splice_init(&chan->queued, &head);
 844
 845         chan->running = NULL;
 846
 847         spin_unlock_irqrestore(&chan->lock, flags);
 848
 849         list_for_each_entry_safe(desc, tmp, &head, node) {
 850                 dev_dbg(chan->nbpf->dma_dev.dev, "%s(): force-free desc %p cookie %d\n",
 851                         __func__, desc, desc->async_tx.cookie);
 852                 list_del(&desc->node);
 853                 nbpf_desc_put(desc);
 854         }
 855 }
 856
 857 static int nbpf_pause(struct dma_chan *dchan)
 858 {
 859         struct nbpf_channel *chan = nbpf_to_chan(dchan);
 860
 861         dev_dbg(dchan->device->dev, "Entry %s\n", __func__);
 862
 863         chan->paused = true;
 864         nbpf_chan_write(chan, NBPF_CHAN_CTRL, NBPF_CHAN_CTRL_SETSUS);
 865         /* See comment in nbpf_prep_one() */
 866         nbpf_chan_write(chan, NBPF_CHAN_CTRL, NBPF_CHAN_CTRL_CLREN);
 867
 868         return 0;
 869 }
 870
 871 static int nbpf_terminate_all(struct dma_chan *dchan)
 872 {
 873         struct nbpf_channel *chan = nbpf_to_chan(dchan);
 874
 875         dev_dbg(dchan->device->dev, "Entry %s\n", __func__);
 876         dev_dbg(dchan->device->dev, "Terminating\n");
 877
 878         nbpf_chan_halt(chan);
 879         nbpf_chan_idle(chan);
 880
 881         return 0;
 882 }
 883
 884 static int nbpf_config(struct dma_chan *dchan,
 885                        struct dma_slave_config *config)
 886 {
 887         struct nbpf_channel *chan = nbpf_to_chan(dchan);
 888
 889         dev_dbg(dchan->device->dev, "Entry %s\n", __func__);
 890
 891         /*
 892          * We could check config->slave_id to match chan->terminal here,
 893          * but with DT they would be coming from the same source, so
 894          * such a check would be superflous
 895          */
 896
 897         chan->slave_dst_addr = config->dst_addr;
 898         chan->slave_dst_width = nbpf_xfer_size(chan->nbpf,
 899                                                config->dst_addr_width, 1);
 900         chan->slave_dst_burst = nbpf_xfer_size(chan->nbpf,
 901                                                config->dst_addr_width,
 902                                                config->dst_maxburst);
 903         chan->slave_src_addr = config->src_addr;
 904         chan->slave_src_width = nbpf_xfer_size(chan->nbpf,
 905                                                config->src_addr_width, 1);
 906         chan->slave_src_burst = nbpf_xfer_size(chan->nbpf,
 907                                                config->src_addr_width,
 908                                                config->src_maxburst);
 909
 910         return 0;
 911 }
 912
 913 static struct dma_async_tx_descriptor *nbpf_prep_sg(struct nbpf_channel *chan,
 914                 struct scatterlist *src_sg, struct scatterlist *dst_sg,
 915                 size_t len, enum dma_transfer_direction direction,
 916                 unsigned long flags)
 917 {
 918         struct nbpf_link_desc *ldesc;
 919         struct scatterlist *mem_sg;
 920         struct nbpf_desc *desc;
 921         bool inc_src, inc_dst;
 922         size_t data_len = 0;
 923         int i = 0;
 924
 925         switch (direction) {
 926         case DMA_DEV_TO_MEM:
 927                 mem_sg = dst_sg;
 928                 inc_src = false;
 929                 inc_dst = true;
 930                 break;
 931
 932         case DMA_MEM_TO_DEV:
 933                 mem_sg = src_sg;
 934                 inc_src = true;
 935                 inc_dst = false;
 936                 break;
 937
 938         default:
 939         case DMA_MEM_TO_MEM:
 940                 mem_sg = src_sg;
 941                 inc_src = true;
 942                 inc_dst = true;
 943         }
 944
 945         desc = nbpf_desc_get(chan, len);
 946         if (!desc)
 947                 return NULL;
 948
 949         desc->async_tx.flags = flags;
 950         desc->async_tx.cookie = -EBUSY;
 951         desc->user_wait = false;
 952
 953         /*
 954          * This is a private descriptor list, and we own the descriptor. No need
 955          * to lock.
 956          */
 957         list_for_each_entry(ldesc, &desc->sg, node) {
 958                 int ret = nbpf_prep_one(ldesc, direction,
 959                                         sg_dma_address(src_sg),
 960                                         sg_dma_address(dst_sg),
 961                                         sg_dma_len(mem_sg),
 962                                         i == len - 1);
 963                 if (ret < 0) {
 964                         nbpf_desc_put(desc);
 965                         return NULL;
 966                 }
 967                 data_len += sg_dma_len(mem_sg);
 968                 if (inc_src)
 969                         src_sg = sg_next(src_sg);
 970                 if (inc_dst)
 971                         dst_sg = sg_next(dst_sg);
 972                 mem_sg = direction == DMA_DEV_TO_MEM ? dst_sg : src_sg;
 973                 i++;
 974         }
 975
 976         desc->length = data_len;
 977
 978         /* The user has to return the descriptor to us ASAP via .tx_submit() */
 979         return &desc->async_tx;
 980 }
 981
 982 static struct dma_async_tx_descriptor *nbpf_prep_memcpy(
 983         struct dma_chan *dchan, dma_addr_t dst, dma_addr_t src,
 984         size_t len, unsigned long flags)
 985 {
 986         struct nbpf_channel *chan = nbpf_to_chan(dchan);
 987         struct scatterlist dst_sg;
 988         struct scatterlist src_sg;
 989
 990         sg_init_table(&dst_sg, 1);
 991         sg_init_table(&src_sg, 1);
 992
 993         sg_dma_address(&dst_sg) = dst;
 994         sg_dma_address(&src_sg) = src;
 995
 996         sg_dma_len(&dst_sg) = len;
 997         sg_dma_len(&src_sg) = len;
 998
 999         dev_dbg(dchan->device->dev, "%s(): %zu @ %pad -> %pad\n",
1000                 __func__, len, &src, &dst);
1001
1002         return nbpf_prep_sg(chan, &src_sg, &dst_sg, 1,
1003                             DMA_MEM_TO_MEM, flags);
1004 }
1005
1006 static struct dma_async_tx_descriptor *nbpf_prep_slave_sg(
1007         struct dma_chan *dchan, struct scatterlist *sgl, unsigned int sg_len,
1008         enum dma_transfer_direction direction, unsigned long flags, void *context)
1009 {
1010         struct nbpf_channel *chan = nbpf_to_chan(dchan);
1011         struct scatterlist slave_sg;
1012
1013         dev_dbg(dchan->device->dev, "Entry %s()\n", __func__);
1014
1015         sg_init_table(&slave_sg, 1);
1016
1017         switch (direction) {
1018         case DMA_MEM_TO_DEV:
1019                 sg_dma_address(&slave_sg) = chan->slave_dst_addr;
1020                 return nbpf_prep_sg(chan, sgl, &slave_sg, sg_len,
1021                                     direction, flags);
1022
1023         case DMA_DEV_TO_MEM:
1024                 sg_dma_address(&slave_sg) = chan->slave_src_addr;
1025                 return nbpf_prep_sg(chan, &slave_sg, sgl, sg_len,
1026                                     direction, flags);
1027
1028         default:
1029                 return NULL;
1030         }
1031 }
1032
1033 static int nbpf_alloc_chan_resources(struct dma_chan *dchan)
1034 {
1035         struct nbpf_channel *chan = nbpf_to_chan(dchan);
1036         int ret;
1037
1038         INIT_LIST_HEAD(&chan->free);
1039         INIT_LIST_HEAD(&chan->free_links);
1040         INIT_LIST_HEAD(&chan->queued);
1041         INIT_LIST_HEAD(&chan->active);
1042         INIT_LIST_HEAD(&chan->done);
1043
1044         ret = nbpf_desc_page_alloc(chan);
1045         if (ret < 0)
1046                 return ret;
1047
1048         dev_dbg(dchan->device->dev, "Entry %s(): terminal %u\n", __func__,
1049                 chan->terminal);
1050
1051         nbpf_chan_configure(chan);
1052
1053         return ret;
1054 }
1055
1056 static void nbpf_free_chan_resources(struct dma_chan *dchan)
1057 {
1058         struct nbpf_channel *chan = nbpf_to_chan(dchan);
1059         struct nbpf_desc_page *dpage, *tmp;
1060
1061         dev_dbg(dchan->device->dev, "Entry %s()\n", __func__);
1062
1063         nbpf_chan_halt(chan);
1064         nbpf_chan_idle(chan);
1065         /* Clean up for if a channel is re-used for MEMCPY after slave DMA */
1066         nbpf_chan_prepare_default(chan);
1067
1068         list_for_each_entry_safe(dpage, tmp, &chan->desc_page, node) {
1069                 struct nbpf_link_desc *ldesc;
1070                 int i;
1071                 list_del(&dpage->node);
1072                 for (i = 0, ldesc = dpage->ldesc;
1073                      i < ARRAY_SIZE(dpage->ldesc);
1074                      i++, ldesc++)
1075                         dma_unmap_single(dchan->device->dev, ldesc->hwdesc_dma_addr,
1076                                          sizeof(*ldesc->hwdesc), DMA_TO_DEVICE);
1077                 free_page((unsigned long)dpage);
1078         }
1079 }
1080
1081 static struct dma_chan *nbpf_of_xlate(struct of_phandle_args *dma_spec,
1082                                       struct of_dma *ofdma)
1083 {
1084         struct nbpf_device *nbpf = ofdma->of_dma_data;
1085         struct dma_chan *dchan;
1086         struct nbpf_channel *chan;
1087
1088         if (dma_spec->args_count != 2)
1089                 return NULL;
1090
1091         dchan = dma_get_any_slave_channel(&nbpf->dma_dev);
1092         if (!dchan)
1093                 return NULL;
1094
1095         dev_dbg(dchan->device->dev, "Entry %s(%pOFn)\n", __func__,
1096                 dma_spec->np);
1097
1098         chan = nbpf_to_chan(dchan);
1099
1100         chan->terminal = dma_spec->args[0];
1101         chan->flags = dma_spec->args[1];
1102
1103         nbpf_chan_prepare(chan);
1104         nbpf_chan_configure(chan);
1105
1106         return dchan;
1107 }
1108
1109 static void nbpf_chan_tasklet(unsigned long data)
1110 {
1111         struct nbpf_channel *chan = (struct nbpf_channel *)data;
1112         struct nbpf_desc *desc, *tmp;
1113         struct dmaengine_desc_callback cb;
1114
1115         while (!list_empty(&chan->done)) {
1116                 bool found = false, must_put, recycling = false;
1117
1118                 spin_lock_irq(&chan->lock);
1119
1120                 list_for_each_entry_safe(desc, tmp, &chan->done, node) {
1121                         if (!desc->user_wait) {
1122                                 /* Newly completed descriptor, have to process */
1123                                 found = true;
1124                                 break;
1125                         } else if (async_tx_test_ack(&desc->async_tx)) {
1126                                 /*
1127                                  * This descriptor was waiting for a user ACK,
1128                                  * it can be recycled now.
1129                                  */
1130                                 list_del(&desc->node);
1131                                 spin_unlock_irq(&chan->lock);
1132                                 nbpf_desc_put(desc);
1133                                 recycling = true;
1134                                 break;
1135                         }
1136                 }
1137
1138                 if (recycling)
1139                         continue;
1140
1141                 if (!found) {
1142                         /* This can happen if TERMINATE_ALL has been called */
1143                         spin_unlock_irq(&chan->lock);
1144                         break;
1145                 }
1146
1147                 dma_cookie_complete(&desc->async_tx);
1148
1149                 /*
1150                  * With released lock we cannot dereference desc, maybe it's
1151                  * still on the "done" list
1152                  */
1153                 if (async_tx_test_ack(&desc->async_tx)) {
1154                         list_del(&desc->node);
1155                         must_put = true;
1156                 } else {
1157                         desc->user_wait = true;
1158                         must_put = false;
1159                 }
1160
1161                 dmaengine_desc_get_callback(&desc->async_tx, &cb);
1162
1163                 /* ack and callback completed descriptor */
1164                 spin_unlock_irq(&chan->lock);
1165
1166                 dmaengine_desc_callback_invoke(&cb, NULL);
1167
1168                 if (must_put)
1169                         nbpf_desc_put(desc);
1170         }
1171 }
1172
1173 static irqreturn_t nbpf_chan_irq(int irq, void *dev)
1174 {
1175         struct nbpf_channel *chan = dev;
1176         bool done = nbpf_status_get(chan);
1177         struct nbpf_desc *desc;
1178         irqreturn_t ret;
1179         bool bh = false;
1180
1181         if (!done)
1182                 return IRQ_NONE;
1183
1184         nbpf_status_ack(chan);
1185
1186         dev_dbg(&chan->dma_chan.dev->device, "%s()\n", __func__);
1187
1188         spin_lock(&chan->lock);
1189         desc = chan->running;
1190         if (WARN_ON(!desc)) {
1191                 ret = IRQ_NONE;
1192                 goto unlock;
1193         } else {
1194                 ret = IRQ_HANDLED;
1195                 bh = true;
1196         }
1197
1198         list_move_tail(&desc->node, &chan->done);
1199         chan->running = NULL;
1200
1201         if (!list_empty(&chan->active)) {
1202                 desc = list_first_entry(&chan->active,
1203                                         struct nbpf_desc, node);
1204                 if (!nbpf_start(desc))
1205                         chan->running = desc;
1206         }
1207
1208 unlock:
1209         spin_unlock(&chan->lock);
1210
1211         if (bh)
1212                 tasklet_schedule(&chan->tasklet);
1213
1214         return ret;
1215 }
1216
1217 static irqreturn_t nbpf_err_irq(int irq, void *dev)
1218 {
1219         struct nbpf_device *nbpf = dev;
1220         u32 error = nbpf_error_get(nbpf);
1221
1222         dev_warn(nbpf->dma_dev.dev, "DMA error IRQ %u\n", irq);
1223
1224         if (!error)
1225                 return IRQ_NONE;
1226
1227         do {
1228                 struct nbpf_channel *chan = nbpf_error_get_channel(nbpf, error);
1229                 /* On error: abort all queued transfers, no callback */
1230                 nbpf_error_clear(chan);
1231                 nbpf_chan_idle(chan);
1232                 error = nbpf_error_get(nbpf);
1233         } while (error);
1234
1235         return IRQ_HANDLED;
1236 }
1237
1238 static int nbpf_chan_probe(struct nbpf_device *nbpf, int n)
1239 {
1240         struct dma_device *dma_dev = &nbpf->dma_dev;
1241         struct nbpf_channel *chan = nbpf->chan + n;
1242         int ret;
1243
1244         chan->nbpf = nbpf;
1245         chan->base = nbpf->base + NBPF_REG_CHAN_OFFSET + NBPF_REG_CHAN_SIZE * n;
1246         INIT_LIST_HEAD(&chan->desc_page);
1247         spin_lock_init(&chan->lock);
1248         chan->dma_chan.device = dma_dev;
1249         dma_cookie_init(&chan->dma_chan);
1250         nbpf_chan_prepare_default(chan);
1251
1252         dev_dbg(dma_dev->dev, "%s(): channel %d: -> %p\n", __func__, n, chan->base);
1253
1254         snprintf(chan->name, sizeof(chan->name), "nbpf %d", n);
1255
1256         tasklet_init(&chan->tasklet, nbpf_chan_tasklet, (unsigned long)chan);
1257         ret = devm_request_irq(dma_dev->dev, chan->irq,
1258                         nbpf_chan_irq, IRQF_SHARED,
1259                         chan->name, chan);
1260         if (ret < 0)
1261                 return ret;
1262
1263         /* Add the channel to DMA device channel list */
1264         list_add_tail(&chan->dma_chan.device_node,
1265                       &dma_dev->channels);
1266
1267         return 0;
1268 }
1269
1270 static const struct of_device_id nbpf_match[] = {
1271         {.compatible = "renesas,nbpfaxi64dmac1b4",      .data = &nbpf_cfg[NBPF1B4]},
1272         {.compatible = "renesas,nbpfaxi64dmac1b8",      .data = &nbpf_cfg[NBPF1B8]},
1273         {.compatible = "renesas,nbpfaxi64dmac1b16",     .data = &nbpf_cfg[NBPF1B16]},
1274         {.compatible = "renesas,nbpfaxi64dmac4b4",      .data = &nbpf_cfg[NBPF4B4]},
1275         {.compatible = "renesas,nbpfaxi64dmac4b8",      .data = &nbpf_cfg[NBPF4B8]},
1276         {.compatible = "renesas,nbpfaxi64dmac4b16",     .data = &nbpf_cfg[NBPF4B16]},
1277         {.compatible = "renesas,nbpfaxi64dmac8b4",      .data = &nbpf_cfg[NBPF8B4]},
1278         {.compatible = "renesas,nbpfaxi64dmac8b8",      .data = &nbpf_cfg[NBPF8B8]},
1279         {.compatible = "renesas,nbpfaxi64dmac8b16",     .data = &nbpf_cfg[NBPF8B16]},
1280         {}
1281 };
1282 MODULE_DEVICE_TABLE(of, nbpf_match);
1283
1284 static int nbpf_probe(struct platform_device *pdev)
1285 {
1286         struct device *dev = &pdev->dev;
1287         struct device_node *np = dev->of_node;
1288         struct nbpf_device *nbpf;
1289         struct dma_device *dma_dev;
1290         struct resource *iomem, *irq_res;
1291         const struct nbpf_config *cfg;
1292         int num_channels;
1293         int ret, irq, eirq, i;
1294         int irqbuf[9] /* maximum 8 channels + error IRQ */;
1295         unsigned int irqs = 0;
1296
1297         BUILD_BUG_ON(sizeof(struct nbpf_desc_page) > PAGE_SIZE);
1298
1299         /* DT only */
1300         if (!np)
1301                 return -ENODEV;
1302
1303         cfg = of_device_get_match_data(dev);
1304         num_channels = cfg->num_channels;
1305
1306         nbpf = devm_kzalloc(dev, struct_size(nbpf, chan, num_channels),
1307                             GFP_KERNEL);
1308         if (!nbpf)
1309                 return -ENOMEM;
1310
1311         dma_dev = &nbpf->dma_dev;
1312         dma_dev->dev = dev;
1313
1314         iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1315         nbpf->base = devm_ioremap_resource(dev, iomem);
1316         if (IS_ERR(nbpf->base))
1317                 return PTR_ERR(nbpf->base);
1318
1319         nbpf->clk = devm_clk_get(dev, NULL);
1320         if (IS_ERR(nbpf->clk))
1321                 return PTR_ERR(nbpf->clk);
1322
1323         of_property_read_u32(np, "max-burst-mem-read",
1324                              &nbpf->max_burst_mem_read);
1325         of_property_read_u32(np, "max-burst-mem-write",
1326                              &nbpf->max_burst_mem_write);
1327
1328         nbpf->config = cfg;
1329
1330         for (i = 0; irqs < ARRAY_SIZE(irqbuf); i++) {
1331                 irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
1332                 if (!irq_res)
1333                         break;
1334
1335                 for (irq = irq_res->start; irq <= irq_res->end;
1336                      irq++, irqs++)
1337                         irqbuf[irqs] = irq;
1338         }
1339
1340         /*
1341          * 3 IRQ resource schemes are supported:
1342          * 1. 1 shared IRQ for error and all channels
1343          * 2. 2 IRQs: one for error and one shared for all channels
1344          * 3. 1 IRQ for error and an own IRQ for each channel
1345          */
1346         if (irqs != 1 && irqs != 2 && irqs != num_channels + 1)
1347                 return -ENXIO;
1348
1349         if (irqs == 1) {
1350                 eirq = irqbuf[0];
1351
1352                 for (i = 0; i <= num_channels; i++)
1353                         nbpf->chan[i].irq = irqbuf[0];
1354         } else {
1355                 eirq = platform_get_irq_byname(pdev, "error");
1356                 if (eirq < 0)
1357                         return eirq;
1358
1359                 if (irqs == num_channels + 1) {
1360                         struct nbpf_channel *chan;
1361
1362                         for (i = 0, chan = nbpf->chan; i <= num_channels;
1363                              i++, chan++) {
1364                                 /* Skip the error IRQ */
1365                                 if (irqbuf[i] == eirq)
1366                                         i++;
1367                                 chan->irq = irqbuf[i];
1368                         }
1369
1370                         if (chan != nbpf->chan + num_channels)
1371                                 return -EINVAL;
1372                 } else {
1373                         /* 2 IRQs and more than one channel */
1374                         if (irqbuf[0] == eirq)
1375                                 irq = irqbuf[1];
1376                         else
1377                                 irq = irqbuf[0];
1378
1379                         for (i = 0; i <= num_channels; i++)
1380                                 nbpf->chan[i].irq = irq;
1381                 }
1382         }
1383
1384         ret = devm_request_irq(dev, eirq, nbpf_err_irq,
1385                                IRQF_SHARED, "dma error", nbpf);
1386         if (ret < 0)
1387                 return ret;
1388         nbpf->eirq = eirq;
1389
1390         INIT_LIST_HEAD(&dma_dev->channels);
1391
1392         /* Create DMA Channel */
1393         for (i = 0; i < num_channels; i++) {
1394                 ret = nbpf_chan_probe(nbpf, i);
1395                 if (ret < 0)
1396                         return ret;
1397         }
1398
1399         dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
1400         dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);
1401         dma_cap_set(DMA_PRIVATE, dma_dev->cap_mask);
1402
1403         /* Common and MEMCPY operations */
1404         dma_dev->device_alloc_chan_resources
1405                 = nbpf_alloc_chan_resources;
1406         dma_dev->device_free_chan_resources = nbpf_free_chan_resources;
1407         dma_dev->device_prep_dma_memcpy = nbpf_prep_memcpy;
1408         dma_dev->device_tx_status = nbpf_tx_status;
1409         dma_dev->device_issue_pending = nbpf_issue_pending;
1410
1411         /*
1412          * If we drop support for unaligned MEMCPY buffer addresses and / or
1413          * lengths by setting
1414          * dma_dev->copy_align = 4;
1415          * then we can set transfer length to 4 bytes in nbpf_prep_one() for
1416          * DMA_MEM_TO_MEM
1417          */
1418
1419         /* Compulsory for DMA_SLAVE fields */
1420         dma_dev->device_prep_slave_sg = nbpf_prep_slave_sg;
1421         dma_dev->device_config = nbpf_config;
1422         dma_dev->device_pause = nbpf_pause;
1423         dma_dev->device_terminate_all = nbpf_terminate_all;
1424
1425         dma_dev->src_addr_widths = NBPF_DMA_BUSWIDTHS;
1426         dma_dev->dst_addr_widths = NBPF_DMA_BUSWIDTHS;
1427         dma_dev->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1428
1429         platform_set_drvdata(pdev, nbpf);
1430
1431         ret = clk_prepare_enable(nbpf->clk);
1432         if (ret < 0)
1433                 return ret;
1434
1435         nbpf_configure(nbpf);
1436
1437         ret = dma_async_device_register(dma_dev);
1438         if (ret < 0)
1439                 goto e_clk_off;
1440
1441         ret = of_dma_controller_register(np, nbpf_of_xlate, nbpf);
1442         if (ret < 0)
1443                 goto e_dma_dev_unreg;
1444
1445         return 0;
1446
1447 e_dma_dev_unreg:
1448         dma_async_device_unregister(dma_dev);
1449 e_clk_off:
1450         clk_disable_unprepare(nbpf->clk);
1451
1452         return ret;
1453 }
1454
1455 static int nbpf_remove(struct platform_device *pdev)
1456 {
1457         struct nbpf_device *nbpf = platform_get_drvdata(pdev);
1458         int i;
1459
1460         devm_free_irq(&pdev->dev, nbpf->eirq, nbpf);
1461
1462         for (i = 0; i < nbpf->config->num_channels; i++) {
1463                 struct nbpf_channel *chan = nbpf->chan + i;
1464
1465                 devm_free_irq(&pdev->dev, chan->irq, chan);
1466
1467                 tasklet_kill(&chan->tasklet);
1468         }
1469
1470         of_dma_controller_free(pdev->dev.of_node);
1471         dma_async_device_unregister(&nbpf->dma_dev);
1472         clk_disable_unprepare(nbpf->clk);
1473
1474         return 0;
1475 }
1476
1477 static const struct platform_device_id nbpf_ids[] = {
1478         {"nbpfaxi64dmac1b4",    (kernel_ulong_t)&nbpf_cfg[NBPF1B4]},
1479         {"nbpfaxi64dmac1b8",    (kernel_ulong_t)&nbpf_cfg[NBPF1B8]},
1480         {"nbpfaxi64dmac1b16",   (kernel_ulong_t)&nbpf_cfg[NBPF1B16]},
1481         {"nbpfaxi64dmac4b4",    (kernel_ulong_t)&nbpf_cfg[NBPF4B4]},
1482         {"nbpfaxi64dmac4b8",    (kernel_ulong_t)&nbpf_cfg[NBPF4B8]},
1483         {"nbpfaxi64dmac4b16",   (kernel_ulong_t)&nbpf_cfg[NBPF4B16]},
1484         {"nbpfaxi64dmac8b4",    (kernel_ulong_t)&nbpf_cfg[NBPF8B4]},
1485         {"nbpfaxi64dmac8b8",    (kernel_ulong_t)&nbpf_cfg[NBPF8B8]},
1486         {"nbpfaxi64dmac8b16",   (kernel_ulong_t)&nbpf_cfg[NBPF8B16]},
1487         {},
1488 };
1489 MODULE_DEVICE_TABLE(platform, nbpf_ids);
1490
1491 #ifdef CONFIG_PM
1492 static int nbpf_runtime_suspend(struct device *dev)
1493 {
1494         struct nbpf_device *nbpf = platform_get_drvdata(to_platform_device(dev));
1495         clk_disable_unprepare(nbpf->clk);
1496         return 0;
1497 }
1498
1499 static int nbpf_runtime_resume(struct device *dev)
1500 {
1501         struct nbpf_device *nbpf = platform_get_drvdata(to_platform_device(dev));
1502         return clk_prepare_enable(nbpf->clk);
1503 }
1504 #endif
1505
1506 static const struct dev_pm_ops nbpf_pm_ops = {
1507         SET_RUNTIME_PM_OPS(nbpf_runtime_suspend, nbpf_runtime_resume, NULL)
1508 };
1509
1510 static struct platform_driver nbpf_driver = {
1511         .driver = {
1512                 .name = "dma-nbpf",
1513                 .of_match_table = nbpf_match,
1514                 .pm = &nbpf_pm_ops,
1515         },
1516         .id_table = nbpf_ids,
1517         .probe = nbpf_probe,
1518         .remove = nbpf_remove,
1519 };
1520
1521 module_platform_driver(nbpf_driver);
1522
1523 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
1524 MODULE_DESCRIPTION("dmaengine driver for NBPFAXI64* DMACs");
1525 MODULE_LICENSE("GPL v2");