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                 /* Search for event handler */
 284                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 285                 reg = NULL;
 286                 list_for_each(l, &sclp_reg_list) {
 287                         reg = list_entry(l, struct sclp_register, list);
 288                         if (reg->receive_mask & (1 << (32 - evbuf->type)))
 289                                 break;
 290                         else
 291                                 reg = NULL;
 292                 }
 293                 if (reg && reg->receiver_fn) {
 294                         spin_unlock_irqrestore(&sclp_lock, flags);
 295                         reg->receiver_fn(evbuf);
 296                         spin_lock_irqsave(&sclp_lock, flags);
 297                 } else if (reg == NULL)
 298                         rc = -ENOSYS;
 299         }
 300         spin_unlock_irqrestore(&sclp_lock, flags);
 301         return rc;
 302 }
 303
 304 /* Read event data request callback. */
 305 static void
 306 sclp_read_cb(struct sclp_req *req, void *data)
 307 {
 308         unsigned long flags;
 309         struct sccb_header *sccb;
 310
 311         sccb = (struct sccb_header *) req->sccb;
 312         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 313             sccb->response_code == 0x220))
 314                 sclp_dispatch_evbufs(sccb);
 315         spin_lock_irqsave(&sclp_lock, flags);
 316         sclp_reading_state = sclp_reading_state_idle;
 317         spin_unlock_irqrestore(&sclp_lock, flags);
 318 }
 319
 320 /* Prepare read event data request. Called while sclp_lock is locked. */
 321 static void __sclp_make_read_req(void)
 322 {
 323         struct sccb_header *sccb;
 324
 325         sccb = (struct sccb_header *) sclp_read_sccb;
 326         clear_page(sccb);
 327         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 328         sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
 329         sclp_read_req.status = SCLP_REQ_QUEUED;
 330         sclp_read_req.start_count = 0;
 331         sclp_read_req.callback = sclp_read_cb;
 332         sclp_read_req.sccb = sccb;
 333         sccb->length = PAGE_SIZE;
 334         sccb->function_code = 0;
 335         sccb->control_mask[2] = 0x80;
 336 }
 337
 338 /* Search request list for request with matching sccb. Return request if found,
 339  * NULL otherwise. Called while sclp_lock is locked. */
 340 static inline struct sclp_req *
 341 __sclp_find_req(u32 sccb)
 342 {
 343         struct list_head *l;
 344         struct sclp_req *req;
 345
 346         list_for_each(l, &sclp_req_queue) {
 347                 req = list_entry(l, struct sclp_req, list);
 348                 if (sccb == (u32) (addr_t) req->sccb)
 349                                 return req;
 350         }
 351         return NULL;
 352 }
 353
 354 /* Handler for external interruption. Perform request post-processing.
 355  * Prepare read event data request if necessary. Start processing of next
 356  * request on queue. */
 357 static void
 358 sclp_interrupt_handler(__u16 code)
 359 {
 360         struct sclp_req *req;
 361         u32 finished_sccb;
 362         u32 evbuf_pending;
 363
 364         spin_lock(&sclp_lock);
 365         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 366         evbuf_pending = S390_lowcore.ext_params & 0x3;
 367         if (finished_sccb) {
 368                 del_timer(&sclp_request_timer);
 369                 sclp_running_state = sclp_running_state_reset_pending;
 370                 req = __sclp_find_req(finished_sccb);
 371                 if (req) {
 372                         /* Request post-processing */
 373                         list_del(&req->list);
 374                         req->status = SCLP_REQ_DONE;
 375                         if (req->callback) {
 376                                 spin_unlock(&sclp_lock);
 377                                 req->callback(req, req->callback_data);
 378                                 spin_lock(&sclp_lock);
 379                         }
 380                 }
 381                 sclp_running_state = sclp_running_state_idle;
 382         }
 383         if (evbuf_pending &&
 384             sclp_activation_state == sclp_activation_state_active)
 385                 __sclp_queue_read_req();
 386         spin_unlock(&sclp_lock);
 387         sclp_process_queue();
 388 }
 389
 390 /* Convert interval in jiffies to TOD ticks. */
 391 static inline u64
 392 sclp_tod_from_jiffies(unsigned long jiffies)
 393 {
 394         return (u64) (jiffies / HZ) << 32;
 395 }
 396
 397 /* Wait until a currently running request finished. Note: while this function
 398  * is running, no timers are served on the calling CPU. */
 399 void
 400 sclp_sync_wait(void)
 401 {
 402         unsigned long long old_tick;
 403         unsigned long flags;
 404         unsigned long cr0, cr0_sync;
 405         u64 timeout;
 406         int irq_context;
 407
 408         /* We'll be disabling timer interrupts, so we need a custom timeout
 409          * mechanism */
 410         timeout = 0;
 411         if (timer_pending(&sclp_request_timer)) {
 412                 /* Get timeout TOD value */
 413                 timeout = get_clock() +
 414                           sclp_tod_from_jiffies(sclp_request_timer.expires -
 415                                                 jiffies);
 416         }
 417         local_irq_save(flags);
 418         /* Prevent bottom half from executing once we force interrupts open */
 419         irq_context = in_interrupt();
 420         if (!irq_context)
 421                 local_bh_disable();
 422         /* Enable service-signal interruption, disable timer interrupts */
 423         old_tick = local_tick_disable();
 424         trace_hardirqs_on();
 425         __ctl_store(cr0, 0, 0);
 426         cr0_sync = cr0;
 427         cr0_sync &= 0xffff00a0;
 428         cr0_sync |= 0x00000200;
 429         __ctl_load(cr0_sync, 0, 0);
 430         __raw_local_irq_stosm(0x01);
 431         /* Loop until driver state indicates finished request */
 432         while (sclp_running_state != sclp_running_state_idle) {
 433                 /* Check for expired request timer */
 434                 if (timer_pending(&sclp_request_timer) &&
 435                     get_clock() > timeout &&
 436                     del_timer(&sclp_request_timer))
 437                         sclp_request_timer.function(sclp_request_timer.data);
 438                 cpu_relax();
 439         }
 440         local_irq_disable();
 441         __ctl_load(cr0, 0, 0);
 442         if (!irq_context)
 443                 _local_bh_enable();
 444         local_tick_enable(old_tick);
 445         local_irq_restore(flags);
 446 }
 447 EXPORT_SYMBOL(sclp_sync_wait);
 448
 449 /* Dispatch changes in send and receive mask to registered listeners. */
 450 static void
 451 sclp_dispatch_state_change(void)
 452 {
 453         struct list_head *l;
 454         struct sclp_register *reg;
 455         unsigned long flags;
 456         sccb_mask_t receive_mask;
 457         sccb_mask_t send_mask;
 458
 459         do {
 460                 spin_lock_irqsave(&sclp_lock, flags);
 461                 reg = NULL;
 462                 list_for_each(l, &sclp_reg_list) {
 463                         reg = list_entry(l, struct sclp_register, list);
 464                         receive_mask = reg->send_mask & sclp_receive_mask;
 465                         send_mask = reg->receive_mask & sclp_send_mask;
 466                         if (reg->sclp_receive_mask != receive_mask ||
 467                             reg->sclp_send_mask != send_mask) {
 468                                 reg->sclp_receive_mask = receive_mask;
 469                                 reg->sclp_send_mask = send_mask;
 470                                 break;
 471                         } else
 472                                 reg = NULL;
 473                 }
 474                 spin_unlock_irqrestore(&sclp_lock, flags);
 475                 if (reg && reg->state_change_fn)
 476                         reg->state_change_fn(reg);
 477         } while (reg);
 478 }
 479
 480 struct sclp_statechangebuf {
 481         struct evbuf_header     header;
 482         u8              validity_sclp_active_facility_mask : 1;
 483         u8              validity_sclp_receive_mask : 1;
 484         u8              validity_sclp_send_mask : 1;
 485         u8              validity_read_data_function_mask : 1;
 486         u16             _zeros : 12;
 487         u16             mask_length;
 488         u64             sclp_active_facility_mask;
 489         sccb_mask_t     sclp_receive_mask;
 490         sccb_mask_t     sclp_send_mask;
 491         u32             read_data_function_mask;
 492 } __attribute__((packed));
 493
 494
 495 /* State change event callback. Inform listeners of changes. */
 496 static void
 497 sclp_state_change_cb(struct evbuf_header *evbuf)
 498 {
 499         unsigned long flags;
 500         struct sclp_statechangebuf *scbuf;
 501
 502         scbuf = (struct sclp_statechangebuf *) evbuf;
 503         if (scbuf->mask_length != sizeof(sccb_mask_t))
 504                 return;
 505         spin_lock_irqsave(&sclp_lock, flags);
 506         if (scbuf->validity_sclp_receive_mask)
 507                 sclp_receive_mask = scbuf->sclp_receive_mask;
 508         if (scbuf->validity_sclp_send_mask)
 509                 sclp_send_mask = scbuf->sclp_send_mask;
 510         spin_unlock_irqrestore(&sclp_lock, flags);
 511         if (scbuf->validity_sclp_active_facility_mask)
 512                 sclp_facilities = scbuf->sclp_active_facility_mask;
 513         sclp_dispatch_state_change();
 514 }
 515
 516 static struct sclp_register sclp_state_change_event = {
 517         .receive_mask = EVTYP_STATECHANGE_MASK,
 518         .receiver_fn = sclp_state_change_cb
 519 };
 520
 521 /* Calculate receive and send mask of currently registered listeners.
 522  * Called while sclp_lock is locked. */
 523 static inline void
 524 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 525 {
 526         struct list_head *l;
 527         struct sclp_register *t;
 528
 529         *receive_mask = 0;
 530         *send_mask = 0;
 531         list_for_each(l, &sclp_reg_list) {
 532                 t = list_entry(l, struct sclp_register, list);
 533                 *receive_mask |= t->receive_mask;
 534                 *send_mask |= t->send_mask;
 535         }
 536 }
 537
 538 /* Register event listener. Return 0 on success, non-zero otherwise. */
 539 int
 540 sclp_register(struct sclp_register *reg)
 541 {
 542         unsigned long flags;
 543         sccb_mask_t receive_mask;
 544         sccb_mask_t send_mask;
 545         int rc;
 546
 547         rc = sclp_init();
 548         if (rc)
 549                 return rc;
 550         spin_lock_irqsave(&sclp_lock, flags);
 551         /* Check event mask for collisions */
 552         __sclp_get_mask(&receive_mask, &send_mask);
 553         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 554                 spin_unlock_irqrestore(&sclp_lock, flags);
 555                 return -EBUSY;
 556         }
 557         /* Trigger initial state change callback */
 558         reg->sclp_receive_mask = 0;
 559         reg->sclp_send_mask = 0;
 560         list_add(&reg->list, &sclp_reg_list);
 561         spin_unlock_irqrestore(&sclp_lock, flags);
 562         rc = sclp_init_mask(1);
 563         if (rc) {
 564                 spin_lock_irqsave(&sclp_lock, flags);
 565                 list_del(&reg->list);
 566                 spin_unlock_irqrestore(&sclp_lock, flags);
 567         }
 568         return rc;
 569 }
 570
 571 EXPORT_SYMBOL(sclp_register);
 572
 573 /* Unregister event listener. */
 574 void
 575 sclp_unregister(struct sclp_register *reg)
 576 {
 577         unsigned long flags;
 578
 579         spin_lock_irqsave(&sclp_lock, flags);
 580         list_del(&reg->list);
 581         spin_unlock_irqrestore(&sclp_lock, flags);
 582         sclp_init_mask(1);
 583 }
 584
 585 EXPORT_SYMBOL(sclp_unregister);
 586
 587 /* Remove event buffers which are marked processed. Return the number of
 588  * remaining event buffers. */
 589 int
 590 sclp_remove_processed(struct sccb_header *sccb)
 591 {
 592         struct evbuf_header *evbuf;
 593         int unprocessed;
 594         u16 remaining;
 595
 596         evbuf = (struct evbuf_header *) (sccb + 1);
 597         unprocessed = 0;
 598         remaining = sccb->length - sizeof(struct sccb_header);
 599         while (remaining > 0) {
 600                 remaining -= evbuf->length;
 601                 if (evbuf->flags & 0x80) {
 602                         sccb->length -= evbuf->length;
 603                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 604                                remaining);
 605                 } else {
 606                         unprocessed++;
 607                         evbuf = (struct evbuf_header *)
 608                                         ((addr_t) evbuf + evbuf->length);
 609                 }
 610         }
 611         return unprocessed;
 612 }
 613
 614 EXPORT_SYMBOL(sclp_remove_processed);
 615
 616 struct init_sccb {
 617         struct sccb_header header;
 618         u16 _reserved;
 619         u16 mask_length;
 620         sccb_mask_t receive_mask;
 621         sccb_mask_t send_mask;
 622         sccb_mask_t sclp_receive_mask;
 623         sccb_mask_t sclp_send_mask;
 624 } __attribute__((packed));
 625
 626 /* Prepare init mask request. Called while sclp_lock is locked. */
 627 static inline void
 628 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 629 {
 630         struct init_sccb *sccb;
 631
 632         sccb = (struct init_sccb *) sclp_init_sccb;
 633         clear_page(sccb);
 634         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 635         sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 636         sclp_init_req.status = SCLP_REQ_FILLED;
 637         sclp_init_req.start_count = 0;
 638         sclp_init_req.callback = NULL;
 639         sclp_init_req.callback_data = NULL;
 640         sclp_init_req.sccb = sccb;
 641         sccb->header.length = sizeof(struct init_sccb);
 642         sccb->mask_length = sizeof(sccb_mask_t);
 643         sccb->receive_mask = receive_mask;
 644         sccb->send_mask = send_mask;
 645         sccb->sclp_receive_mask = 0;
 646         sccb->sclp_send_mask = 0;
 647 }
 648
 649 /* Start init mask request. If calculate is non-zero, calculate the mask as
 650  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 651  * success, non-zero otherwise. */
 652 static int
 653 sclp_init_mask(int calculate)
 654 {
 655         unsigned long flags;
 656         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 657         sccb_mask_t receive_mask;
 658         sccb_mask_t send_mask;
 659         int retry;
 660         int rc;
 661         unsigned long wait;
 662
 663         spin_lock_irqsave(&sclp_lock, flags);
 664         /* Check if interface is in appropriate state */
 665         if (sclp_mask_state != sclp_mask_state_idle) {
 666                 spin_unlock_irqrestore(&sclp_lock, flags);
 667                 return -EBUSY;
 668         }
 669         if (sclp_activation_state == sclp_activation_state_inactive) {
 670                 spin_unlock_irqrestore(&sclp_lock, flags);
 671                 return -EINVAL;
 672         }
 673         sclp_mask_state = sclp_mask_state_initializing;
 674         /* Determine mask */
 675         if (calculate)
 676                 __sclp_get_mask(&receive_mask, &send_mask);
 677         else {
 678                 receive_mask = 0;
 679                 send_mask = 0;
 680         }
 681         rc = -EIO;
 682         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 683                 /* Prepare request */
 684                 __sclp_make_init_req(receive_mask, send_mask);
 685                 spin_unlock_irqrestore(&sclp_lock, flags);
 686                 if (sclp_add_request(&sclp_init_req)) {
 687                         /* Try again later */
 688                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 689                         while (time_before(jiffies, wait))
 690                                 sclp_sync_wait();
 691                         spin_lock_irqsave(&sclp_lock, flags);
 692                         continue;
 693                 }
 694                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 695                        sclp_init_req.status != SCLP_REQ_FAILED)
 696                         sclp_sync_wait();
 697                 spin_lock_irqsave(&sclp_lock, flags);
 698                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 699                     sccb->header.response_code == 0x20) {
 700                         /* Successful request */
 701                         if (calculate) {
 702                                 sclp_receive_mask = sccb->sclp_receive_mask;
 703                                 sclp_send_mask = sccb->sclp_send_mask;
 704                         } else {
 705                                 sclp_receive_mask = 0;
 706                                 sclp_send_mask = 0;
 707                         }
 708                         spin_unlock_irqrestore(&sclp_lock, flags);
 709                         sclp_dispatch_state_change();
 710                         spin_lock_irqsave(&sclp_lock, flags);
 711                         rc = 0;
 712                         break;
 713                 }
 714         }
 715         sclp_mask_state = sclp_mask_state_idle;
 716         spin_unlock_irqrestore(&sclp_lock, flags);
 717         return rc;
 718 }
 719
 720 /* Deactivate SCLP interface. On success, new requests will be rejected,
 721  * events will no longer be dispatched. Return 0 on success, non-zero
 722  * otherwise. */
 723 int
 724 sclp_deactivate(void)
 725 {
 726         unsigned long flags;
 727         int rc;
 728
 729         spin_lock_irqsave(&sclp_lock, flags);
 730         /* Deactivate can only be called when active */
 731         if (sclp_activation_state != sclp_activation_state_active) {
 732                 spin_unlock_irqrestore(&sclp_lock, flags);
 733                 return -EINVAL;
 734         }
 735         sclp_activation_state = sclp_activation_state_deactivating;
 736         spin_unlock_irqrestore(&sclp_lock, flags);
 737         rc = sclp_init_mask(0);
 738         spin_lock_irqsave(&sclp_lock, flags);
 739         if (rc == 0)
 740                 sclp_activation_state = sclp_activation_state_inactive;
 741         else
 742                 sclp_activation_state = sclp_activation_state_active;
 743         spin_unlock_irqrestore(&sclp_lock, flags);
 744         return rc;
 745 }
 746
 747 EXPORT_SYMBOL(sclp_deactivate);
 748
 749 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 750  * requests will be accepted, events will be dispatched again. Return 0 on
 751  * success, non-zero otherwise. */
 752 int
 753 sclp_reactivate(void)
 754 {
 755         unsigned long flags;
 756         int rc;
 757
 758         spin_lock_irqsave(&sclp_lock, flags);
 759         /* Reactivate can only be called when inactive */
 760         if (sclp_activation_state != sclp_activation_state_inactive) {
 761                 spin_unlock_irqrestore(&sclp_lock, flags);
 762                 return -EINVAL;
 763         }
 764         sclp_activation_state = sclp_activation_state_activating;
 765         spin_unlock_irqrestore(&sclp_lock, flags);
 766         rc = sclp_init_mask(1);
 767         spin_lock_irqsave(&sclp_lock, flags);
 768         if (rc == 0)
 769                 sclp_activation_state = sclp_activation_state_active;
 770         else
 771                 sclp_activation_state = sclp_activation_state_inactive;
 772         spin_unlock_irqrestore(&sclp_lock, flags);
 773         return rc;
 774 }
 775
 776 EXPORT_SYMBOL(sclp_reactivate);
 777
 778 /* Handler for external interruption used during initialization. Modify
 779  * request state to done. */
 780 static void
 781 sclp_check_handler(__u16 code)
 782 {
 783         u32 finished_sccb;
 784
 785         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 786         /* Is this the interrupt we are waiting for? */
 787         if (finished_sccb == 0)
 788                 return;
 789         if (finished_sccb != (u32) (addr_t) sclp_init_sccb)
 790                 panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
 791                       finished_sccb);
 792         spin_lock(&sclp_lock);
 793         if (sclp_running_state == sclp_running_state_running) {
 794                 sclp_init_req.status = SCLP_REQ_DONE;
 795                 sclp_running_state = sclp_running_state_idle;
 796         }
 797         spin_unlock(&sclp_lock);
 798 }
 799
 800 /* Initial init mask request timed out. Modify request state to failed. */
 801 static void
 802 sclp_check_timeout(unsigned long data)
 803 {
 804         unsigned long flags;
 805
 806         spin_lock_irqsave(&sclp_lock, flags);
 807         if (sclp_running_state == sclp_running_state_running) {
 808                 sclp_init_req.status = SCLP_REQ_FAILED;
 809                 sclp_running_state = sclp_running_state_idle;
 810         }
 811         spin_unlock_irqrestore(&sclp_lock, flags);
 812 }
 813
 814 /* Perform a check of the SCLP interface. Return zero if the interface is
 815  * available and there are no pending requests from a previous instance.
 816  * Return non-zero otherwise. */
 817 static int
 818 sclp_check_interface(void)
 819 {
 820         struct init_sccb *sccb;
 821         unsigned long flags;
 822         int retry;
 823         int rc;
 824
 825         spin_lock_irqsave(&sclp_lock, flags);
 826         /* Prepare init mask command */
 827         rc = register_early_external_interrupt(0x2401, sclp_check_handler,
 828                                                &ext_int_info_hwc);
 829         if (rc) {
 830                 spin_unlock_irqrestore(&sclp_lock, flags);
 831                 return rc;
 832         }
 833         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 834                 __sclp_make_init_req(0, 0);
 835                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 836                 rc = sclp_service_call(sclp_init_req.command, sccb);
 837                 if (rc == -EIO)
 838                         break;
 839                 sclp_init_req.status = SCLP_REQ_RUNNING;
 840                 sclp_running_state = sclp_running_state_running;
 841                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 842                                          sclp_check_timeout, 0);
 843                 spin_unlock_irqrestore(&sclp_lock, flags);
 844                 /* Enable service-signal interruption - needs to happen
 845                  * with IRQs enabled. */
 846                 ctl_set_bit(0, 9);
 847                 /* Wait for signal from interrupt or timeout */
 848                 sclp_sync_wait();
 849                 /* Disable service-signal interruption - needs to happen
 850                  * with IRQs enabled. */
 851                 ctl_clear_bit(0,9);
 852                 spin_lock_irqsave(&sclp_lock, flags);
 853                 del_timer(&sclp_request_timer);
 854                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 855                     sccb->header.response_code == 0x20) {
 856                         rc = 0;
 857                         break;
 858                 } else
 859                         rc = -EBUSY;
 860         }
 861         unregister_early_external_interrupt(0x2401, sclp_check_handler,
 862                                             &ext_int_info_hwc);
 863         spin_unlock_irqrestore(&sclp_lock, flags);
 864         return rc;
 865 }
 866
 867 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 868  * events from interfering with rebooted system. */
 869 static int
 870 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 871 {
 872         sclp_deactivate();
 873         return NOTIFY_DONE;
 874 }
 875
 876 static struct notifier_block sclp_reboot_notifier = {
 877         .notifier_call = sclp_reboot_event
 878 };
 879
 880 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
 881  * otherwise. */
 882 static int
 883 sclp_init(void)
 884 {
 885         unsigned long flags;
 886         int rc;
 887
 888         spin_lock_irqsave(&sclp_lock, flags);
 889         /* Check for previous or running initialization */
 890         if (sclp_init_state != sclp_init_state_uninitialized) {
 891                 spin_unlock_irqrestore(&sclp_lock, flags);
 892                 return 0;
 893         }
 894         sclp_init_state = sclp_init_state_initializing;
 895         /* Set up variables */
 896         INIT_LIST_HEAD(&sclp_req_queue);
 897         INIT_LIST_HEAD(&sclp_reg_list);
 898         list_add(&sclp_state_change_event.list, &sclp_reg_list);
 899         init_timer(&sclp_request_timer);
 900         /* Check interface */
 901         spin_unlock_irqrestore(&sclp_lock, flags);
 902         rc = sclp_check_interface();
 903         spin_lock_irqsave(&sclp_lock, flags);
 904         if (rc) {
 905                 sclp_init_state = sclp_init_state_uninitialized;
 906                 spin_unlock_irqrestore(&sclp_lock, flags);
 907                 return rc;
 908         }
 909         /* Register reboot handler */
 910         rc = register_reboot_notifier(&sclp_reboot_notifier);
 911         if (rc) {
 912                 sclp_init_state = sclp_init_state_uninitialized;
 913                 spin_unlock_irqrestore(&sclp_lock, flags);
 914                 return rc;
 915         }
 916         /* Register interrupt handler */
 917         rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler,
 918                                                &ext_int_info_hwc);
 919         if (rc) {
 920                 unregister_reboot_notifier(&sclp_reboot_notifier);
 921                 sclp_init_state = sclp_init_state_uninitialized;
 922                 spin_unlock_irqrestore(&sclp_lock, flags);
 923                 return rc;
 924         }
 925         sclp_init_state = sclp_init_state_initialized;
 926         spin_unlock_irqrestore(&sclp_lock, flags);
 927         /* Enable service-signal external interruption - needs to happen with
 928          * IRQs enabled. */
 929         ctl_set_bit(0, 9);
 930         sclp_init_mask(1);
 931         return 0;
 932 }
 933
 934 static __init int sclp_initcall(void)
 935 {
 936         return sclp_init();
 937 }
 938
 939 arch_initcall(sclp_initcall);