drivers/s390/char/sclp.c

   1 /*
   2  *  drivers/s390/char/sclp.c
   3  *     core function to access sclp interface
   4  *
   5  *  S390 version
   6  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
   7  *    Author(s): Martin Peschke <mpeschke@de.ibm.com>
   8  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/err.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/timer.h>
  16 #include <linux/reboot.h>
  17 #include <linux/jiffies.h>
  18 #include <linux/init.h>
  19 #include <asm/types.h>
  20 #include <asm/s390_ext.h>
  21
  22 #include "sclp.h"
  23
  24 #define SCLP_HEADER             "sclp: "
  25
  26 /* Structure for register_early_external_interrupt. */
  27 static ext_int_info_t ext_int_info_hwc;
  28
  29 /* Lock to protect internal data consistency. */
  30 static DEFINE_SPINLOCK(sclp_lock);
  31
  32 /* Mask of events that we can send to the sclp interface. */
  33 static sccb_mask_t sclp_receive_mask;
  34
  35 /* Mask of events that we can receive from the sclp interface. */
  36 static sccb_mask_t sclp_send_mask;
  37
  38 /* List of registered event listeners and senders. */
  39 static struct list_head sclp_reg_list;
  40
  41 /* List of queued requests. */
  42 static struct list_head sclp_req_queue;
  43
  44 /* Data for read and and init requests. */
  45 static struct sclp_req sclp_read_req;
  46 static struct sclp_req sclp_init_req;
  47 static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  48 static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  49
  50 /* Timer for request retries. */
  51 static struct timer_list sclp_request_timer;
  52
  53 /* Internal state: is the driver initialized? */
  54 static volatile enum sclp_init_state_t {
  55         sclp_init_state_uninitialized,
  56         sclp_init_state_initializing,
  57         sclp_init_state_initialized
  58 } sclp_init_state = sclp_init_state_uninitialized;
  59
  60 /* Internal state: is a request active at the sclp? */
  61 static volatile enum sclp_running_state_t {
  62         sclp_running_state_idle,
  63         sclp_running_state_running,
  64         sclp_running_state_reset_pending
  65 } sclp_running_state = sclp_running_state_idle;
  66
  67 /* Internal state: is a read request pending? */
  68 static volatile enum sclp_reading_state_t {
  69         sclp_reading_state_idle,
  70         sclp_reading_state_reading
  71 } sclp_reading_state = sclp_reading_state_idle;
  72
  73 /* Internal state: is the driver currently serving requests? */
  74 static volatile enum sclp_activation_state_t {
  75         sclp_activation_state_active,
  76         sclp_activation_state_deactivating,
  77         sclp_activation_state_inactive,
  78         sclp_activation_state_activating
  79 } sclp_activation_state = sclp_activation_state_active;
  80
  81 /* Internal state: is an init mask request pending? */
  82 static volatile enum sclp_mask_state_t {
  83         sclp_mask_state_idle,
  84         sclp_mask_state_initializing
  85 } sclp_mask_state = sclp_mask_state_idle;
  86
  87 /* Maximum retry counts */
  88 #define SCLP_INIT_RETRY         3
  89 #define SCLP_MASK_RETRY         3
  90
  91 /* Timeout intervals in seconds.*/
  92 #define SCLP_BUSY_INTERVAL      10
  93 #define SCLP_RETRY_INTERVAL     30
  94
  95 static void sclp_process_queue(void);
  96 static void __sclp_make_read_req(void);
  97 static int sclp_init_mask(int calculate);
  98 static int sclp_init(void);
  99
 100 /* Perform service call. Return 0 on success, non-zero otherwise. */
 101 int
 102 sclp_service_call(sclp_cmdw_t command, void *sccb)
 103 {
 104         int cc;
 105
 106         asm volatile(
 107                 "       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
 108                 "       ipm     %0\n"
 109                 "       srl     %0,28"
 110                 : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
 111                 : "cc", "memory");
 112         if (cc == 3)
 113                 return -EIO;
 114         if (cc == 2)
 115                 return -EBUSY;
 116         return 0;
 117 }
 118
 119
 120 static void
 121 __sclp_queue_read_req(void)
 122 {
 123         if (sclp_reading_state == sclp_reading_state_idle) {
 124                 sclp_reading_state = sclp_reading_state_reading;
 125                 __sclp_make_read_req();
 126                 /* Add request to head of queue */
 127                 list_add(&sclp_read_req.list, &sclp_req_queue);
 128         }
 129 }
 130
 131 /* Set up request retry timer. Called while sclp_lock is locked. */
 132 static inline void
 133 __sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
 134                          unsigned long data)
 135 {
 136         del_timer(&sclp_request_timer);
 137         sclp_request_timer.function = function;
 138         sclp_request_timer.data = data;
 139         sclp_request_timer.expires = jiffies + time;
 140         add_timer(&sclp_request_timer);
 141 }
 142
 143 /* Request timeout handler. Restart the request queue. If DATA is non-zero,
 144  * force restart of running request. */
 145 static void
 146 sclp_request_timeout(unsigned long data)
 147 {
 148         unsigned long flags;
 149
 150         spin_lock_irqsave(&sclp_lock, flags);
 151         if (data) {
 152                 if (sclp_running_state == sclp_running_state_running) {
 153                         /* Break running state and queue NOP read event request
 154                          * to get a defined interface state. */
 155                         __sclp_queue_read_req();
 156                         sclp_running_state = sclp_running_state_idle;
 157                 }
 158         } else {
 159                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 160                                          sclp_request_timeout, 0);
 161         }
 162         spin_unlock_irqrestore(&sclp_lock, flags);
 163         sclp_process_queue();
 164 }
 165
 166 /* Try to start a request. Return zero if the request was successfully
 167  * started or if it will be started at a later time. Return non-zero otherwise.
 168  * Called while sclp_lock is locked. */
 169 static int
 170 __sclp_start_request(struct sclp_req *req)
 171 {
 172         int rc;
 173
 174         if (sclp_running_state != sclp_running_state_idle)
 175                 return 0;
 176         del_timer(&sclp_request_timer);
 177         rc = sclp_service_call(req->command, req->sccb);
 178         req->start_count++;
 179
 180         if (rc == 0) {
 181                 /* Sucessfully started request */
 182                 req->status = SCLP_REQ_RUNNING;
 183                 sclp_running_state = sclp_running_state_running;
 184                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 185                                          sclp_request_timeout, 1);
 186                 return 0;
 187         } else if (rc == -EBUSY) {
 188                 /* Try again later */
 189                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 190                                          sclp_request_timeout, 0);
 191                 return 0;
 192         }
 193         /* Request failed */
 194         req->status = SCLP_REQ_FAILED;
 195         return rc;
 196 }
 197
 198 /* Try to start queued requests. */
 199 static void
 200 sclp_process_queue(void)
 201 {
 202         struct sclp_req *req;
 203         int rc;
 204         unsigned long flags;
 205
 206         spin_lock_irqsave(&sclp_lock, flags);
 207         if (sclp_running_state != sclp_running_state_idle) {
 208                 spin_unlock_irqrestore(&sclp_lock, flags);
 209                 return;
 210         }
 211         del_timer(&sclp_request_timer);
 212         while (!list_empty(&sclp_req_queue)) {
 213                 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
 214                 rc = __sclp_start_request(req);
 215                 if (rc == 0)
 216                         break;
 217                 /* Request failed */
 218                 if (req->start_count > 1) {
 219                         /* Cannot abort already submitted request - could still
 220                          * be active at the SCLP */
 221                         __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 222                                                  sclp_request_timeout, 0);
 223                         break;
 224                 }
 225                 /* Post-processing for aborted request */
 226                 list_del(&req->list);
 227                 if (req->callback) {
 228                         spin_unlock_irqrestore(&sclp_lock, flags);
 229                         req->callback(req, req->callback_data);
 230                         spin_lock_irqsave(&sclp_lock, flags);
 231                 }
 232         }
 233         spin_unlock_irqrestore(&sclp_lock, flags);
 234 }
 235
 236 /* Queue a new request. Return zero on success, non-zero otherwise. */
 237 int
 238 sclp_add_request(struct sclp_req *req)
 239 {
 240         unsigned long flags;
 241         int rc;
 242
 243         spin_lock_irqsave(&sclp_lock, flags);
 244         if ((sclp_init_state != sclp_init_state_initialized ||
 245              sclp_activation_state != sclp_activation_state_active) &&
 246             req != &sclp_init_req) {
 247                 spin_unlock_irqrestore(&sclp_lock, flags);
 248                 return -EIO;
 249         }
 250         req->status = SCLP_REQ_QUEUED;
 251         req->start_count = 0;
 252         list_add_tail(&req->list, &sclp_req_queue);
 253         rc = 0;
 254         /* Start if request is first in list */
 255         if (sclp_running_state == sclp_running_state_idle &&
 256             req->list.prev == &sclp_req_queue) {
 257                 rc = __sclp_start_request(req);
 258                 if (rc)
 259                         list_del(&req->list);
 260         }
 261         spin_unlock_irqrestore(&sclp_lock, flags);
 262         return rc;
 263 }
 264
 265 EXPORT_SYMBOL(sclp_add_request);
 266
 267 /* Dispatch events found in request buffer to registered listeners. Return 0
 268  * if all events were dispatched, non-zero otherwise. */
 269 static int
 270 sclp_dispatch_evbufs(struct sccb_header *sccb)
 271 {
 272         unsigned long flags;
 273         struct evbuf_header *evbuf;
 274         struct list_head *l;
 275         struct sclp_register *reg;
 276         int offset;
 277         int rc;
 278
 279         spin_lock_irqsave(&sclp_lock, flags);
 280         rc = 0;
 281         for (offset = sizeof(struct sccb_header); offset < sccb->length;
 282              offset += evbuf->length) {
 283                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 284                 /* Check for malformed hardware response */
 285                 if (evbuf->length == 0)
 286                         break;
 287                 /* Search for event handler */
 288                 reg = NULL;
 289                 list_for_each(l, &sclp_reg_list) {
 290                         reg = list_entry(l, struct sclp_register, list);
 291                         if (reg->receive_mask & (1 << (32 - evbuf->type)))
 292                                 break;
 293                         else
 294                                 reg = NULL;
 295                 }
 296                 if (reg && reg->receiver_fn) {
 297                         spin_unlock_irqrestore(&sclp_lock, flags);
 298                         reg->receiver_fn(evbuf);
 299                         spin_lock_irqsave(&sclp_lock, flags);
 300                 } else if (reg == NULL)
 301                         rc = -ENOSYS;
 302         }
 303         spin_unlock_irqrestore(&sclp_lock, flags);
 304         return rc;
 305 }
 306
 307 /* Read event data request callback. */
 308 static void
 309 sclp_read_cb(struct sclp_req *req, void *data)
 310 {
 311         unsigned long flags;
 312         struct sccb_header *sccb;
 313
 314         sccb = (struct sccb_header *) req->sccb;
 315         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 316             sccb->response_code == 0x220))
 317                 sclp_dispatch_evbufs(sccb);
 318         spin_lock_irqsave(&sclp_lock, flags);
 319         sclp_reading_state = sclp_reading_state_idle;
 320         spin_unlock_irqrestore(&sclp_lock, flags);
 321 }
 322
 323 /* Prepare read event data request. Called while sclp_lock is locked. */
 324 static void __sclp_make_read_req(void)
 325 {
 326         struct sccb_header *sccb;
 327
 328         sccb = (struct sccb_header *) sclp_read_sccb;
 329         clear_page(sccb);
 330         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 331         sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
 332         sclp_read_req.status = SCLP_REQ_QUEUED;
 333         sclp_read_req.start_count = 0;
 334         sclp_read_req.callback = sclp_read_cb;
 335         sclp_read_req.sccb = sccb;
 336         sccb->length = PAGE_SIZE;
 337         sccb->function_code = 0;
 338         sccb->control_mask[2] = 0x80;
 339 }
 340
 341 /* Search request list for request with matching sccb. Return request if found,
 342  * NULL otherwise. Called while sclp_lock is locked. */
 343 static inline struct sclp_req *
 344 __sclp_find_req(u32 sccb)
 345 {
 346         struct list_head *l;
 347         struct sclp_req *req;
 348
 349         list_for_each(l, &sclp_req_queue) {
 350                 req = list_entry(l, struct sclp_req, list);
 351                 if (sccb == (u32) (addr_t) req->sccb)
 352                                 return req;
 353         }
 354         return NULL;
 355 }
 356
 357 /* Handler for external interruption. Perform request post-processing.
 358  * Prepare read event data request if necessary. Start processing of next
 359  * request on queue. */
 360 static void
 361 sclp_interrupt_handler(__u16 code)
 362 {
 363         struct sclp_req *req;
 364         u32 finished_sccb;
 365         u32 evbuf_pending;
 366
 367         spin_lock(&sclp_lock);
 368         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 369         evbuf_pending = S390_lowcore.ext_params & 0x3;
 370         if (finished_sccb) {
 371                 del_timer(&sclp_request_timer);
 372                 sclp_running_state = sclp_running_state_reset_pending;
 373                 req = __sclp_find_req(finished_sccb);
 374                 if (req) {
 375                         /* Request post-processing */
 376                         list_del(&req->list);
 377                         req->status = SCLP_REQ_DONE;
 378                         if (req->callback) {
 379                                 spin_unlock(&sclp_lock);
 380                                 req->callback(req, req->callback_data);
 381                                 spin_lock(&sclp_lock);
 382                         }
 383                 }
 384                 sclp_running_state = sclp_running_state_idle;
 385         }
 386         if (evbuf_pending &&
 387             sclp_activation_state == sclp_activation_state_active)
 388                 __sclp_queue_read_req();
 389         spin_unlock(&sclp_lock);
 390         sclp_process_queue();
 391 }
 392
 393 /* Convert interval in jiffies to TOD ticks. */
 394 static inline u64
 395 sclp_tod_from_jiffies(unsigned long jiffies)
 396 {
 397         return (u64) (jiffies / HZ) << 32;
 398 }
 399
 400 /* Wait until a currently running request finished. Note: while this function
 401  * is running, no timers are served on the calling CPU. */
 402 void
 403 sclp_sync_wait(void)
 404 {
 405         unsigned long long old_tick;
 406         unsigned long flags;
 407         unsigned long cr0, cr0_sync;
 408         u64 timeout;
 409         int irq_context;
 410
 411         /* We'll be disabling timer interrupts, so we need a custom timeout
 412          * mechanism */
 413         timeout = 0;
 414         if (timer_pending(&sclp_request_timer)) {
 415                 /* Get timeout TOD value */
 416                 timeout = get_clock() +
 417                           sclp_tod_from_jiffies(sclp_request_timer.expires -
 418                                                 jiffies);
 419         }
 420         local_irq_save(flags);
 421         /* Prevent bottom half from executing once we force interrupts open */
 422         irq_context = in_interrupt();
 423         if (!irq_context)
 424                 local_bh_disable();
 425         /* Enable service-signal interruption, disable timer interrupts */
 426         old_tick = local_tick_disable();
 427         trace_hardirqs_on();
 428         __ctl_store(cr0, 0, 0);
 429         cr0_sync = cr0;
 430         cr0_sync &= 0xffff00a0;
 431         cr0_sync |= 0x00000200;
 432         __ctl_load(cr0_sync, 0, 0);
 433         __raw_local_irq_stosm(0x01);
 434         /* Loop until driver state indicates finished request */
 435         while (sclp_running_state != sclp_running_state_idle) {
 436                 /* Check for expired request timer */
 437                 if (timer_pending(&sclp_request_timer) &&
 438                     get_clock() > timeout &&
 439                     del_timer(&sclp_request_timer))
 440                         sclp_request_timer.function(sclp_request_timer.data);
 441                 cpu_relax();
 442         }
 443         local_irq_disable();
 444         __ctl_load(cr0, 0, 0);
 445         if (!irq_context)
 446                 _local_bh_enable();
 447         local_tick_enable(old_tick);
 448         local_irq_restore(flags);
 449 }
 450 EXPORT_SYMBOL(sclp_sync_wait);
 451
 452 /* Dispatch changes in send and receive mask to registered listeners. */
 453 static void
 454 sclp_dispatch_state_change(void)
 455 {
 456         struct list_head *l;
 457         struct sclp_register *reg;
 458         unsigned long flags;
 459         sccb_mask_t receive_mask;
 460         sccb_mask_t send_mask;
 461
 462         do {
 463                 spin_lock_irqsave(&sclp_lock, flags);
 464                 reg = NULL;
 465                 list_for_each(l, &sclp_reg_list) {
 466                         reg = list_entry(l, struct sclp_register, list);
 467                         receive_mask = reg->send_mask & sclp_receive_mask;
 468                         send_mask = reg->receive_mask & sclp_send_mask;
 469                         if (reg->sclp_receive_mask != receive_mask ||
 470                             reg->sclp_send_mask != send_mask) {
 471                                 reg->sclp_receive_mask = receive_mask;
 472                                 reg->sclp_send_mask = send_mask;
 473                                 break;
 474                         } else
 475                                 reg = NULL;
 476                 }
 477                 spin_unlock_irqrestore(&sclp_lock, flags);
 478                 if (reg && reg->state_change_fn)
 479                         reg->state_change_fn(reg);
 480         } while (reg);
 481 }
 482
 483 struct sclp_statechangebuf {
 484         struct evbuf_header     header;
 485         u8              validity_sclp_active_facility_mask : 1;
 486         u8              validity_sclp_receive_mask : 1;
 487         u8              validity_sclp_send_mask : 1;
 488         u8              validity_read_data_function_mask : 1;
 489         u16             _zeros : 12;
 490         u16             mask_length;
 491         u64             sclp_active_facility_mask;
 492         sccb_mask_t     sclp_receive_mask;
 493         sccb_mask_t     sclp_send_mask;
 494         u32             read_data_function_mask;
 495 } __attribute__((packed));
 496
 497
 498 /* State change event callback. Inform listeners of changes. */
 499 static void
 500 sclp_state_change_cb(struct evbuf_header *evbuf)
 501 {
 502         unsigned long flags;
 503         struct sclp_statechangebuf *scbuf;
 504
 505         scbuf = (struct sclp_statechangebuf *) evbuf;
 506         if (scbuf->mask_length != sizeof(sccb_mask_t))
 507                 return;
 508         spin_lock_irqsave(&sclp_lock, flags);
 509         if (scbuf->validity_sclp_receive_mask)
 510                 sclp_receive_mask = scbuf->sclp_receive_mask;
 511         if (scbuf->validity_sclp_send_mask)
 512                 sclp_send_mask = scbuf->sclp_send_mask;
 513         spin_unlock_irqrestore(&sclp_lock, flags);
 514         if (scbuf->validity_sclp_active_facility_mask)
 515                 sclp_facilities = scbuf->sclp_active_facility_mask;
 516         sclp_dispatch_state_change();
 517 }
 518
 519 static struct sclp_register sclp_state_change_event = {
 520         .receive_mask = EVTYP_STATECHANGE_MASK,
 521         .receiver_fn = sclp_state_change_cb
 522 };
 523
 524 /* Calculate receive and send mask of currently registered listeners.
 525  * Called while sclp_lock is locked. */
 526 static inline void
 527 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 528 {
 529         struct list_head *l;
 530         struct sclp_register *t;
 531
 532         *receive_mask = 0;
 533         *send_mask = 0;
 534         list_for_each(l, &sclp_reg_list) {
 535                 t = list_entry(l, struct sclp_register, list);
 536                 *receive_mask |= t->receive_mask;
 537                 *send_mask |= t->send_mask;
 538         }
 539 }
 540
 541 /* Register event listener. Return 0 on success, non-zero otherwise. */
 542 int
 543 sclp_register(struct sclp_register *reg)
 544 {
 545         unsigned long flags;
 546         sccb_mask_t receive_mask;
 547         sccb_mask_t send_mask;
 548         int rc;
 549
 550         rc = sclp_init();
 551         if (rc)
 552                 return rc;
 553         spin_lock_irqsave(&sclp_lock, flags);
 554         /* Check event mask for collisions */
 555         __sclp_get_mask(&receive_mask, &send_mask);
 556         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 557                 spin_unlock_irqrestore(&sclp_lock, flags);
 558                 return -EBUSY;
 559         }
 560         /* Trigger initial state change callback */
 561         reg->sclp_receive_mask = 0;
 562         reg->sclp_send_mask = 0;
 563         list_add(&reg->list, &sclp_reg_list);
 564         spin_unlock_irqrestore(&sclp_lock, flags);
 565         rc = sclp_init_mask(1);
 566         if (rc) {
 567                 spin_lock_irqsave(&sclp_lock, flags);
 568                 list_del(&reg->list);
 569                 spin_unlock_irqrestore(&sclp_lock, flags);
 570         }
 571         return rc;
 572 }
 573
 574 EXPORT_SYMBOL(sclp_register);
 575
 576 /* Unregister event listener. */
 577 void
 578 sclp_unregister(struct sclp_register *reg)
 579 {
 580         unsigned long flags;
 581
 582         spin_lock_irqsave(&sclp_lock, flags);
 583         list_del(&reg->list);
 584         spin_unlock_irqrestore(&sclp_lock, flags);
 585         sclp_init_mask(1);
 586 }
 587
 588 EXPORT_SYMBOL(sclp_unregister);
 589
 590 /* Remove event buffers which are marked processed. Return the number of
 591  * remaining event buffers. */
 592 int
 593 sclp_remove_processed(struct sccb_header *sccb)
 594 {
 595         struct evbuf_header *evbuf;
 596         int unprocessed;
 597         u16 remaining;
 598
 599         evbuf = (struct evbuf_header *) (sccb + 1);
 600         unprocessed = 0;
 601         remaining = sccb->length - sizeof(struct sccb_header);
 602         while (remaining > 0) {
 603                 remaining -= evbuf->length;
 604                 if (evbuf->flags & 0x80) {
 605                         sccb->length -= evbuf->length;
 606                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 607                                remaining);
 608                 } else {
 609                         unprocessed++;
 610                         evbuf = (struct evbuf_header *)
 611                                         ((addr_t) evbuf + evbuf->length);
 612                 }
 613         }
 614         return unprocessed;
 615 }
 616
 617 EXPORT_SYMBOL(sclp_remove_processed);
 618
 619 struct init_sccb {
 620         struct sccb_header header;
 621         u16 _reserved;
 622         u16 mask_length;
 623         sccb_mask_t receive_mask;
 624         sccb_mask_t send_mask;
 625         sccb_mask_t sclp_receive_mask;
 626         sccb_mask_t sclp_send_mask;
 627 } __attribute__((packed));
 628
 629 /* Prepare init mask request. Called while sclp_lock is locked. */
 630 static inline void
 631 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 632 {
 633         struct init_sccb *sccb;
 634
 635         sccb = (struct init_sccb *) sclp_init_sccb;
 636         clear_page(sccb);
 637         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 638         sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 639         sclp_init_req.status = SCLP_REQ_FILLED;
 640         sclp_init_req.start_count = 0;
 641         sclp_init_req.callback = NULL;
 642         sclp_init_req.callback_data = NULL;
 643         sclp_init_req.sccb = sccb;
 644         sccb->header.length = sizeof(struct init_sccb);
 645         sccb->mask_length = sizeof(sccb_mask_t);
 646         sccb->receive_mask = receive_mask;
 647         sccb->send_mask = send_mask;
 648         sccb->sclp_receive_mask = 0;
 649         sccb->sclp_send_mask = 0;
 650 }
 651
 652 /* Start init mask request. If calculate is non-zero, calculate the mask as
 653  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 654  * success, non-zero otherwise. */
 655 static int
 656 sclp_init_mask(int calculate)
 657 {
 658         unsigned long flags;
 659         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 660         sccb_mask_t receive_mask;
 661         sccb_mask_t send_mask;
 662         int retry;
 663         int rc;
 664         unsigned long wait;
 665
 666         spin_lock_irqsave(&sclp_lock, flags);
 667         /* Check if interface is in appropriate state */
 668         if (sclp_mask_state != sclp_mask_state_idle) {
 669                 spin_unlock_irqrestore(&sclp_lock, flags);
 670                 return -EBUSY;
 671         }
 672         if (sclp_activation_state == sclp_activation_state_inactive) {
 673                 spin_unlock_irqrestore(&sclp_lock, flags);
 674                 return -EINVAL;
 675         }
 676         sclp_mask_state = sclp_mask_state_initializing;
 677         /* Determine mask */
 678         if (calculate)
 679                 __sclp_get_mask(&receive_mask, &send_mask);
 680         else {
 681                 receive_mask = 0;
 682                 send_mask = 0;
 683         }
 684         rc = -EIO;
 685         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 686                 /* Prepare request */
 687                 __sclp_make_init_req(receive_mask, send_mask);
 688                 spin_unlock_irqrestore(&sclp_lock, flags);
 689                 if (sclp_add_request(&sclp_init_req)) {
 690                         /* Try again later */
 691                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 692                         while (time_before(jiffies, wait))
 693                                 sclp_sync_wait();
 694                         spin_lock_irqsave(&sclp_lock, flags);
 695                         continue;
 696                 }
 697                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 698                        sclp_init_req.status != SCLP_REQ_FAILED)
 699                         sclp_sync_wait();
 700                 spin_lock_irqsave(&sclp_lock, flags);
 701                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 702                     sccb->header.response_code == 0x20) {
 703                         /* Successful request */
 704                         if (calculate) {
 705                                 sclp_receive_mask = sccb->sclp_receive_mask;
 706                                 sclp_send_mask = sccb->sclp_send_mask;
 707                         } else {
 708                                 sclp_receive_mask = 0;
 709                                 sclp_send_mask = 0;
 710                         }
 711                         spin_unlock_irqrestore(&sclp_lock, flags);
 712                         sclp_dispatch_state_change();
 713                         spin_lock_irqsave(&sclp_lock, flags);
 714                         rc = 0;
 715                         break;
 716                 }
 717         }
 718         sclp_mask_state = sclp_mask_state_idle;
 719         spin_unlock_irqrestore(&sclp_lock, flags);
 720         return rc;
 721 }
 722
 723 /* Deactivate SCLP interface. On success, new requests will be rejected,
 724  * events will no longer be dispatched. Return 0 on success, non-zero
 725  * otherwise. */
 726 int
 727 sclp_deactivate(void)
 728 {
 729         unsigned long flags;
 730         int rc;
 731
 732         spin_lock_irqsave(&sclp_lock, flags);
 733         /* Deactivate can only be called when active */
 734         if (sclp_activation_state != sclp_activation_state_active) {
 735                 spin_unlock_irqrestore(&sclp_lock, flags);
 736                 return -EINVAL;
 737         }
 738         sclp_activation_state = sclp_activation_state_deactivating;
 739         spin_unlock_irqrestore(&sclp_lock, flags);
 740         rc = sclp_init_mask(0);
 741         spin_lock_irqsave(&sclp_lock, flags);
 742         if (rc == 0)
 743                 sclp_activation_state = sclp_activation_state_inactive;
 744         else
 745                 sclp_activation_state = sclp_activation_state_active;
 746         spin_unlock_irqrestore(&sclp_lock, flags);
 747         return rc;
 748 }
 749
 750 EXPORT_SYMBOL(sclp_deactivate);
 751
 752 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 753  * requests will be accepted, events will be dispatched again. Return 0 on
 754  * success, non-zero otherwise. */
 755 int
 756 sclp_reactivate(void)
 757 {
 758         unsigned long flags;
 759         int rc;
 760
 761         spin_lock_irqsave(&sclp_lock, flags);
 762         /* Reactivate can only be called when inactive */
 763         if (sclp_activation_state != sclp_activation_state_inactive) {
 764                 spin_unlock_irqrestore(&sclp_lock, flags);
 765                 return -EINVAL;
 766         }
 767         sclp_activation_state = sclp_activation_state_activating;
 768         spin_unlock_irqrestore(&sclp_lock, flags);
 769         rc = sclp_init_mask(1);
 770         spin_lock_irqsave(&sclp_lock, flags);
 771         if (rc == 0)
 772                 sclp_activation_state = sclp_activation_state_active;
 773         else
 774                 sclp_activation_state = sclp_activation_state_inactive;
 775         spin_unlock_irqrestore(&sclp_lock, flags);
 776         return rc;
 777 }
 778
 779 EXPORT_SYMBOL(sclp_reactivate);
 780
 781 /* Handler for external interruption used during initialization. Modify
 782  * request state to done. */
 783 static void
 784 sclp_check_handler(__u16 code)
 785 {
 786         u32 finished_sccb;
 787
 788         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 789         /* Is this the interrupt we are waiting for? */
 790         if (finished_sccb == 0)
 791                 return;
 792         if (finished_sccb != (u32) (addr_t) sclp_init_sccb)
 793                 panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
 794                       finished_sccb);
 795         spin_lock(&sclp_lock);
 796         if (sclp_running_state == sclp_running_state_running) {
 797                 sclp_init_req.status = SCLP_REQ_DONE;
 798                 sclp_running_state = sclp_running_state_idle;
 799         }
 800         spin_unlock(&sclp_lock);
 801 }
 802
 803 /* Initial init mask request timed out. Modify request state to failed. */
 804 static void
 805 sclp_check_timeout(unsigned long data)
 806 {
 807         unsigned long flags;
 808
 809         spin_lock_irqsave(&sclp_lock, flags);
 810         if (sclp_running_state == sclp_running_state_running) {
 811                 sclp_init_req.status = SCLP_REQ_FAILED;
 812                 sclp_running_state = sclp_running_state_idle;
 813         }
 814         spin_unlock_irqrestore(&sclp_lock, flags);
 815 }
 816
 817 /* Perform a check of the SCLP interface. Return zero if the interface is
 818  * available and there are no pending requests from a previous instance.
 819  * Return non-zero otherwise. */
 820 static int
 821 sclp_check_interface(void)
 822 {
 823         struct init_sccb *sccb;
 824         unsigned long flags;
 825         int retry;
 826         int rc;
 827
 828         spin_lock_irqsave(&sclp_lock, flags);
 829         /* Prepare init mask command */
 830         rc = register_early_external_interrupt(0x2401, sclp_check_handler,
 831                                                &ext_int_info_hwc);
 832         if (rc) {
 833                 spin_unlock_irqrestore(&sclp_lock, flags);
 834                 return rc;
 835         }
 836         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 837                 __sclp_make_init_req(0, 0);
 838                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 839                 rc = sclp_service_call(sclp_init_req.command, sccb);
 840                 if (rc == -EIO)
 841                         break;
 842                 sclp_init_req.status = SCLP_REQ_RUNNING;
 843                 sclp_running_state = sclp_running_state_running;
 844                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 845                                          sclp_check_timeout, 0);
 846                 spin_unlock_irqrestore(&sclp_lock, flags);
 847                 /* Enable service-signal interruption - needs to happen
 848                  * with IRQs enabled. */
 849                 ctl_set_bit(0, 9);
 850                 /* Wait for signal from interrupt or timeout */
 851                 sclp_sync_wait();
 852                 /* Disable service-signal interruption - needs to happen
 853                  * with IRQs enabled. */
 854                 ctl_clear_bit(0,9);
 855                 spin_lock_irqsave(&sclp_lock, flags);
 856                 del_timer(&sclp_request_timer);
 857                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 858                     sccb->header.response_code == 0x20) {
 859                         rc = 0;
 860                         break;
 861                 } else
 862                         rc = -EBUSY;
 863         }
 864         unregister_early_external_interrupt(0x2401, sclp_check_handler,
 865                                             &ext_int_info_hwc);
 866         spin_unlock_irqrestore(&sclp_lock, flags);
 867         return rc;
 868 }
 869
 870 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 871  * events from interfering with rebooted system. */
 872 static int
 873 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 874 {
 875         sclp_deactivate();
 876         return NOTIFY_DONE;
 877 }
 878
 879 static struct notifier_block sclp_reboot_notifier = {
 880         .notifier_call = sclp_reboot_event
 881 };
 882
 883 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
 884  * otherwise. */
 885 static int
 886 sclp_init(void)
 887 {
 888         unsigned long flags;
 889         int rc;
 890
 891         spin_lock_irqsave(&sclp_lock, flags);
 892         /* Check for previous or running initialization */
 893         if (sclp_init_state != sclp_init_state_uninitialized) {
 894                 spin_unlock_irqrestore(&sclp_lock, flags);
 895                 return 0;
 896         }
 897         sclp_init_state = sclp_init_state_initializing;
 898         /* Set up variables */
 899         INIT_LIST_HEAD(&sclp_req_queue);
 900         INIT_LIST_HEAD(&sclp_reg_list);
 901         list_add(&sclp_state_change_event.list, &sclp_reg_list);
 902         init_timer(&sclp_request_timer);
 903         /* Check interface */
 904         spin_unlock_irqrestore(&sclp_lock, flags);
 905         rc = sclp_check_interface();
 906         spin_lock_irqsave(&sclp_lock, flags);
 907         if (rc) {
 908                 sclp_init_state = sclp_init_state_uninitialized;
 909                 spin_unlock_irqrestore(&sclp_lock, flags);
 910                 return rc;
 911         }
 912         /* Register reboot handler */
 913         rc = register_reboot_notifier(&sclp_reboot_notifier);
 914         if (rc) {
 915                 sclp_init_state = sclp_init_state_uninitialized;
 916                 spin_unlock_irqrestore(&sclp_lock, flags);
 917                 return rc;
 918         }
 919         /* Register interrupt handler */
 920         rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler,
 921                                                &ext_int_info_hwc);
 922         if (rc) {
 923                 unregister_reboot_notifier(&sclp_reboot_notifier);
 924                 sclp_init_state = sclp_init_state_uninitialized;
 925                 spin_unlock_irqrestore(&sclp_lock, flags);
 926                 return rc;
 927         }
 928         sclp_init_state = sclp_init_state_initialized;
 929         spin_unlock_irqrestore(&sclp_lock, flags);
 930         /* Enable service-signal external interruption - needs to happen with
 931          * IRQs enabled. */
 932         ctl_set_bit(0, 9);
 933         sclp_init_mask(1);
 934         return 0;
 935 }
 936
 937 static __init int sclp_initcall(void)
 938 {
 939         return sclp_init();
 940 }
 941
 942 arch_initcall(sclp_initcall);