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 flags;
 403         unsigned long cr0, cr0_sync;
 404         u64 timeout;
 405         int irq_context;
 406
 407         /* We'll be disabling timer interrupts, so we need a custom timeout
 408          * mechanism */
 409         timeout = 0;
 410         if (timer_pending(&sclp_request_timer)) {
 411                 /* Get timeout TOD value */
 412                 timeout = get_clock() +
 413                           sclp_tod_from_jiffies(sclp_request_timer.expires -
 414                                                 jiffies);
 415         }
 416         local_irq_save(flags);
 417         /* Prevent bottom half from executing once we force interrupts open */
 418         irq_context = in_interrupt();
 419         if (!irq_context)
 420                 local_bh_disable();
 421         /* Enable service-signal interruption, disable timer interrupts */
 422         trace_hardirqs_on();
 423         __ctl_store(cr0, 0, 0);
 424         cr0_sync = cr0;
 425         cr0_sync |= 0x00000200;
 426         cr0_sync &= 0xFFFFF3AC;
 427         __ctl_load(cr0_sync, 0, 0);
 428         __raw_local_irq_stosm(0x01);
 429         /* Loop until driver state indicates finished request */
 430         while (sclp_running_state != sclp_running_state_idle) {
 431                 /* Check for expired request timer */
 432                 if (timer_pending(&sclp_request_timer) &&
 433                     get_clock() > timeout &&
 434                     del_timer(&sclp_request_timer))
 435                         sclp_request_timer.function(sclp_request_timer.data);
 436                 cpu_relax();
 437         }
 438         local_irq_disable();
 439         __ctl_load(cr0, 0, 0);
 440         if (!irq_context)
 441                 _local_bh_enable();
 442         local_irq_restore(flags);
 443 }
 444
 445 EXPORT_SYMBOL(sclp_sync_wait);
 446
 447 /* Dispatch changes in send and receive mask to registered listeners. */
 448 static void
 449 sclp_dispatch_state_change(void)
 450 {
 451         struct list_head *l;
 452         struct sclp_register *reg;
 453         unsigned long flags;
 454         sccb_mask_t receive_mask;
 455         sccb_mask_t send_mask;
 456
 457         do {
 458                 spin_lock_irqsave(&sclp_lock, flags);
 459                 reg = NULL;
 460                 list_for_each(l, &sclp_reg_list) {
 461                         reg = list_entry(l, struct sclp_register, list);
 462                         receive_mask = reg->send_mask & sclp_receive_mask;
 463                         send_mask = reg->receive_mask & sclp_send_mask;
 464                         if (reg->sclp_receive_mask != receive_mask ||
 465                             reg->sclp_send_mask != send_mask) {
 466                                 reg->sclp_receive_mask = receive_mask;
 467                                 reg->sclp_send_mask = send_mask;
 468                                 break;
 469                         } else
 470                                 reg = NULL;
 471                 }
 472                 spin_unlock_irqrestore(&sclp_lock, flags);
 473                 if (reg && reg->state_change_fn)
 474                         reg->state_change_fn(reg);
 475         } while (reg);
 476 }
 477
 478 struct sclp_statechangebuf {
 479         struct evbuf_header     header;
 480         u8              validity_sclp_active_facility_mask : 1;
 481         u8              validity_sclp_receive_mask : 1;
 482         u8              validity_sclp_send_mask : 1;
 483         u8              validity_read_data_function_mask : 1;
 484         u16             _zeros : 12;
 485         u16             mask_length;
 486         u64             sclp_active_facility_mask;
 487         sccb_mask_t     sclp_receive_mask;
 488         sccb_mask_t     sclp_send_mask;
 489         u32             read_data_function_mask;
 490 } __attribute__((packed));
 491
 492
 493 /* State change event callback. Inform listeners of changes. */
 494 static void
 495 sclp_state_change_cb(struct evbuf_header *evbuf)
 496 {
 497         unsigned long flags;
 498         struct sclp_statechangebuf *scbuf;
 499
 500         scbuf = (struct sclp_statechangebuf *) evbuf;
 501         if (scbuf->mask_length != sizeof(sccb_mask_t))
 502                 return;
 503         spin_lock_irqsave(&sclp_lock, flags);
 504         if (scbuf->validity_sclp_receive_mask)
 505                 sclp_receive_mask = scbuf->sclp_receive_mask;
 506         if (scbuf->validity_sclp_send_mask)
 507                 sclp_send_mask = scbuf->sclp_send_mask;
 508         spin_unlock_irqrestore(&sclp_lock, flags);
 509         if (scbuf->validity_sclp_active_facility_mask)
 510                 sclp_facilities = scbuf->sclp_active_facility_mask;
 511         sclp_dispatch_state_change();
 512 }
 513
 514 static struct sclp_register sclp_state_change_event = {
 515         .receive_mask = EVTYP_STATECHANGE_MASK,
 516         .receiver_fn = sclp_state_change_cb
 517 };
 518
 519 /* Calculate receive and send mask of currently registered listeners.
 520  * Called while sclp_lock is locked. */
 521 static inline void
 522 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 523 {
 524         struct list_head *l;
 525         struct sclp_register *t;
 526
 527         *receive_mask = 0;
 528         *send_mask = 0;
 529         list_for_each(l, &sclp_reg_list) {
 530                 t = list_entry(l, struct sclp_register, list);
 531                 *receive_mask |= t->receive_mask;
 532                 *send_mask |= t->send_mask;
 533         }
 534 }
 535
 536 /* Register event listener. Return 0 on success, non-zero otherwise. */
 537 int
 538 sclp_register(struct sclp_register *reg)
 539 {
 540         unsigned long flags;
 541         sccb_mask_t receive_mask;
 542         sccb_mask_t send_mask;
 543         int rc;
 544
 545         rc = sclp_init();
 546         if (rc)
 547                 return rc;
 548         spin_lock_irqsave(&sclp_lock, flags);
 549         /* Check event mask for collisions */
 550         __sclp_get_mask(&receive_mask, &send_mask);
 551         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 552                 spin_unlock_irqrestore(&sclp_lock, flags);
 553                 return -EBUSY;
 554         }
 555         /* Trigger initial state change callback */
 556         reg->sclp_receive_mask = 0;
 557         reg->sclp_send_mask = 0;
 558         list_add(&reg->list, &sclp_reg_list);
 559         spin_unlock_irqrestore(&sclp_lock, flags);
 560         rc = sclp_init_mask(1);
 561         if (rc) {
 562                 spin_lock_irqsave(&sclp_lock, flags);
 563                 list_del(&reg->list);
 564                 spin_unlock_irqrestore(&sclp_lock, flags);
 565         }
 566         return rc;
 567 }
 568
 569 EXPORT_SYMBOL(sclp_register);
 570
 571 /* Unregister event listener. */
 572 void
 573 sclp_unregister(struct sclp_register *reg)
 574 {
 575         unsigned long flags;
 576
 577         spin_lock_irqsave(&sclp_lock, flags);
 578         list_del(&reg->list);
 579         spin_unlock_irqrestore(&sclp_lock, flags);
 580         sclp_init_mask(1);
 581 }
 582
 583 EXPORT_SYMBOL(sclp_unregister);
 584
 585 /* Remove event buffers which are marked processed. Return the number of
 586  * remaining event buffers. */
 587 int
 588 sclp_remove_processed(struct sccb_header *sccb)
 589 {
 590         struct evbuf_header *evbuf;
 591         int unprocessed;
 592         u16 remaining;
 593
 594         evbuf = (struct evbuf_header *) (sccb + 1);
 595         unprocessed = 0;
 596         remaining = sccb->length - sizeof(struct sccb_header);
 597         while (remaining > 0) {
 598                 remaining -= evbuf->length;
 599                 if (evbuf->flags & 0x80) {
 600                         sccb->length -= evbuf->length;
 601                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 602                                remaining);
 603                 } else {
 604                         unprocessed++;
 605                         evbuf = (struct evbuf_header *)
 606                                         ((addr_t) evbuf + evbuf->length);
 607                 }
 608         }
 609         return unprocessed;
 610 }
 611
 612 EXPORT_SYMBOL(sclp_remove_processed);
 613
 614 struct init_sccb {
 615         struct sccb_header header;
 616         u16 _reserved;
 617         u16 mask_length;
 618         sccb_mask_t receive_mask;
 619         sccb_mask_t send_mask;
 620         sccb_mask_t sclp_receive_mask;
 621         sccb_mask_t sclp_send_mask;
 622 } __attribute__((packed));
 623
 624 /* Prepare init mask request. Called while sclp_lock is locked. */
 625 static inline void
 626 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 627 {
 628         struct init_sccb *sccb;
 629
 630         sccb = (struct init_sccb *) sclp_init_sccb;
 631         clear_page(sccb);
 632         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 633         sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 634         sclp_init_req.status = SCLP_REQ_FILLED;
 635         sclp_init_req.start_count = 0;
 636         sclp_init_req.callback = NULL;
 637         sclp_init_req.callback_data = NULL;
 638         sclp_init_req.sccb = sccb;
 639         sccb->header.length = sizeof(struct init_sccb);
 640         sccb->mask_length = sizeof(sccb_mask_t);
 641         sccb->receive_mask = receive_mask;
 642         sccb->send_mask = send_mask;
 643         sccb->sclp_receive_mask = 0;
 644         sccb->sclp_send_mask = 0;
 645 }
 646
 647 /* Start init mask request. If calculate is non-zero, calculate the mask as
 648  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 649  * success, non-zero otherwise. */
 650 static int
 651 sclp_init_mask(int calculate)
 652 {
 653         unsigned long flags;
 654         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 655         sccb_mask_t receive_mask;
 656         sccb_mask_t send_mask;
 657         int retry;
 658         int rc;
 659         unsigned long wait;
 660
 661         spin_lock_irqsave(&sclp_lock, flags);
 662         /* Check if interface is in appropriate state */
 663         if (sclp_mask_state != sclp_mask_state_idle) {
 664                 spin_unlock_irqrestore(&sclp_lock, flags);
 665                 return -EBUSY;
 666         }
 667         if (sclp_activation_state == sclp_activation_state_inactive) {
 668                 spin_unlock_irqrestore(&sclp_lock, flags);
 669                 return -EINVAL;
 670         }
 671         sclp_mask_state = sclp_mask_state_initializing;
 672         /* Determine mask */
 673         if (calculate)
 674                 __sclp_get_mask(&receive_mask, &send_mask);
 675         else {
 676                 receive_mask = 0;
 677                 send_mask = 0;
 678         }
 679         rc = -EIO;
 680         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 681                 /* Prepare request */
 682                 __sclp_make_init_req(receive_mask, send_mask);
 683                 spin_unlock_irqrestore(&sclp_lock, flags);
 684                 if (sclp_add_request(&sclp_init_req)) {
 685                         /* Try again later */
 686                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 687                         while (time_before(jiffies, wait))
 688                                 sclp_sync_wait();
 689                         spin_lock_irqsave(&sclp_lock, flags);
 690                         continue;
 691                 }
 692                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 693                        sclp_init_req.status != SCLP_REQ_FAILED)
 694                         sclp_sync_wait();
 695                 spin_lock_irqsave(&sclp_lock, flags);
 696                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 697                     sccb->header.response_code == 0x20) {
 698                         /* Successful request */
 699                         if (calculate) {
 700                                 sclp_receive_mask = sccb->sclp_receive_mask;
 701                                 sclp_send_mask = sccb->sclp_send_mask;
 702                         } else {
 703                                 sclp_receive_mask = 0;
 704                                 sclp_send_mask = 0;
 705                         }
 706                         spin_unlock_irqrestore(&sclp_lock, flags);
 707                         sclp_dispatch_state_change();
 708                         spin_lock_irqsave(&sclp_lock, flags);
 709                         rc = 0;
 710                         break;
 711                 }
 712         }
 713         sclp_mask_state = sclp_mask_state_idle;
 714         spin_unlock_irqrestore(&sclp_lock, flags);
 715         return rc;
 716 }
 717
 718 /* Deactivate SCLP interface. On success, new requests will be rejected,
 719  * events will no longer be dispatched. Return 0 on success, non-zero
 720  * otherwise. */
 721 int
 722 sclp_deactivate(void)
 723 {
 724         unsigned long flags;
 725         int rc;
 726
 727         spin_lock_irqsave(&sclp_lock, flags);
 728         /* Deactivate can only be called when active */
 729         if (sclp_activation_state != sclp_activation_state_active) {
 730                 spin_unlock_irqrestore(&sclp_lock, flags);
 731                 return -EINVAL;
 732         }
 733         sclp_activation_state = sclp_activation_state_deactivating;
 734         spin_unlock_irqrestore(&sclp_lock, flags);
 735         rc = sclp_init_mask(0);
 736         spin_lock_irqsave(&sclp_lock, flags);
 737         if (rc == 0)
 738                 sclp_activation_state = sclp_activation_state_inactive;
 739         else
 740                 sclp_activation_state = sclp_activation_state_active;
 741         spin_unlock_irqrestore(&sclp_lock, flags);
 742         return rc;
 743 }
 744
 745 EXPORT_SYMBOL(sclp_deactivate);
 746
 747 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 748  * requests will be accepted, events will be dispatched again. Return 0 on
 749  * success, non-zero otherwise. */
 750 int
 751 sclp_reactivate(void)
 752 {
 753         unsigned long flags;
 754         int rc;
 755
 756         spin_lock_irqsave(&sclp_lock, flags);
 757         /* Reactivate can only be called when inactive */
 758         if (sclp_activation_state != sclp_activation_state_inactive) {
 759                 spin_unlock_irqrestore(&sclp_lock, flags);
 760                 return -EINVAL;
 761         }
 762         sclp_activation_state = sclp_activation_state_activating;
 763         spin_unlock_irqrestore(&sclp_lock, flags);
 764         rc = sclp_init_mask(1);
 765         spin_lock_irqsave(&sclp_lock, flags);
 766         if (rc == 0)
 767                 sclp_activation_state = sclp_activation_state_active;
 768         else
 769                 sclp_activation_state = sclp_activation_state_inactive;
 770         spin_unlock_irqrestore(&sclp_lock, flags);
 771         return rc;
 772 }
 773
 774 EXPORT_SYMBOL(sclp_reactivate);
 775
 776 /* Handler for external interruption used during initialization. Modify
 777  * request state to done. */
 778 static void
 779 sclp_check_handler(__u16 code)
 780 {
 781         u32 finished_sccb;
 782
 783         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 784         /* Is this the interrupt we are waiting for? */
 785         if (finished_sccb == 0)
 786                 return;
 787         if (finished_sccb != (u32) (addr_t) sclp_init_sccb)
 788                 panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
 789                       finished_sccb);
 790         spin_lock(&sclp_lock);
 791         if (sclp_running_state == sclp_running_state_running) {
 792                 sclp_init_req.status = SCLP_REQ_DONE;
 793                 sclp_running_state = sclp_running_state_idle;
 794         }
 795         spin_unlock(&sclp_lock);
 796 }
 797
 798 /* Initial init mask request timed out. Modify request state to failed. */
 799 static void
 800 sclp_check_timeout(unsigned long data)
 801 {
 802         unsigned long flags;
 803
 804         spin_lock_irqsave(&sclp_lock, flags);
 805         if (sclp_running_state == sclp_running_state_running) {
 806                 sclp_init_req.status = SCLP_REQ_FAILED;
 807                 sclp_running_state = sclp_running_state_idle;
 808         }
 809         spin_unlock_irqrestore(&sclp_lock, flags);
 810 }
 811
 812 /* Perform a check of the SCLP interface. Return zero if the interface is
 813  * available and there are no pending requests from a previous instance.
 814  * Return non-zero otherwise. */
 815 static int
 816 sclp_check_interface(void)
 817 {
 818         struct init_sccb *sccb;
 819         unsigned long flags;
 820         int retry;
 821         int rc;
 822
 823         spin_lock_irqsave(&sclp_lock, flags);
 824         /* Prepare init mask command */
 825         rc = register_early_external_interrupt(0x2401, sclp_check_handler,
 826                                                &ext_int_info_hwc);
 827         if (rc) {
 828                 spin_unlock_irqrestore(&sclp_lock, flags);
 829                 return rc;
 830         }
 831         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 832                 __sclp_make_init_req(0, 0);
 833                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 834                 rc = sclp_service_call(sclp_init_req.command, sccb);
 835                 if (rc == -EIO)
 836                         break;
 837                 sclp_init_req.status = SCLP_REQ_RUNNING;
 838                 sclp_running_state = sclp_running_state_running;
 839                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 840                                          sclp_check_timeout, 0);
 841                 spin_unlock_irqrestore(&sclp_lock, flags);
 842                 /* Enable service-signal interruption - needs to happen
 843                  * with IRQs enabled. */
 844                 ctl_set_bit(0, 9);
 845                 /* Wait for signal from interrupt or timeout */
 846                 sclp_sync_wait();
 847                 /* Disable service-signal interruption - needs to happen
 848                  * with IRQs enabled. */
 849                 ctl_clear_bit(0,9);
 850                 spin_lock_irqsave(&sclp_lock, flags);
 851                 del_timer(&sclp_request_timer);
 852                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 853                     sccb->header.response_code == 0x20) {
 854                         rc = 0;
 855                         break;
 856                 } else
 857                         rc = -EBUSY;
 858         }
 859         unregister_early_external_interrupt(0x2401, sclp_check_handler,
 860                                             &ext_int_info_hwc);
 861         spin_unlock_irqrestore(&sclp_lock, flags);
 862         return rc;
 863 }
 864
 865 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 866  * events from interfering with rebooted system. */
 867 static int
 868 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 869 {
 870         sclp_deactivate();
 871         return NOTIFY_DONE;
 872 }
 873
 874 static struct notifier_block sclp_reboot_notifier = {
 875         .notifier_call = sclp_reboot_event
 876 };
 877
 878 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
 879  * otherwise. */
 880 static int
 881 sclp_init(void)
 882 {
 883         unsigned long flags;
 884         int rc;
 885
 886         spin_lock_irqsave(&sclp_lock, flags);
 887         /* Check for previous or running initialization */
 888         if (sclp_init_state != sclp_init_state_uninitialized) {
 889                 spin_unlock_irqrestore(&sclp_lock, flags);
 890                 return 0;
 891         }
 892         sclp_init_state = sclp_init_state_initializing;
 893         /* Set up variables */
 894         INIT_LIST_HEAD(&sclp_req_queue);
 895         INIT_LIST_HEAD(&sclp_reg_list);
 896         list_add(&sclp_state_change_event.list, &sclp_reg_list);
 897         init_timer(&sclp_request_timer);
 898         /* Check interface */
 899         spin_unlock_irqrestore(&sclp_lock, flags);
 900         rc = sclp_check_interface();
 901         spin_lock_irqsave(&sclp_lock, flags);
 902         if (rc) {
 903                 sclp_init_state = sclp_init_state_uninitialized;
 904                 spin_unlock_irqrestore(&sclp_lock, flags);
 905                 return rc;
 906         }
 907         /* Register reboot handler */
 908         rc = register_reboot_notifier(&sclp_reboot_notifier);
 909         if (rc) {
 910                 sclp_init_state = sclp_init_state_uninitialized;
 911                 spin_unlock_irqrestore(&sclp_lock, flags);
 912                 return rc;
 913         }
 914         /* Register interrupt handler */
 915         rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler,
 916                                                &ext_int_info_hwc);
 917         if (rc) {
 918                 unregister_reboot_notifier(&sclp_reboot_notifier);
 919                 sclp_init_state = sclp_init_state_uninitialized;
 920                 spin_unlock_irqrestore(&sclp_lock, flags);
 921                 return rc;
 922         }
 923         sclp_init_state = sclp_init_state_initialized;
 924         spin_unlock_irqrestore(&sclp_lock, flags);
 925         /* Enable service-signal external interruption - needs to happen with
 926          * IRQs enabled. */
 927         ctl_set_bit(0, 9);
 928         sclp_init_mask(1);
 929         return 0;
 930 }
 931
 932 static __init int sclp_initcall(void)
 933 {
 934         return sclp_init();
 935 }
 936
 937 arch_initcall(sclp_initcall);