drivers/s390/char/sclp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * core function to access sclp interface
   4  *
   5  * Copyright IBM Corp. 1999, 2009
   6  *
   7  * Author(s): Martin Peschke <mpeschke@de.ibm.com>
   8  *            Martin Schwidefsky <schwidefsky@de.ibm.com>
   9  */
  10
  11 #include <linux/kernel_stat.h>
  12 #include <linux/module.h>
  13 #include <linux/err.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/timer.h>
  17 #include <linux/reboot.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/init.h>
  20 #include <linux/suspend.h>
  21 #include <linux/completion.h>
  22 #include <linux/platform_device.h>
  23 #include <asm/types.h>
  24 #include <asm/irq.h>
  25
  26 #include "sclp.h"
  27
  28 #define SCLP_HEADER             "sclp: "
  29
  30 /* Lock to protect internal data consistency. */
  31 static DEFINE_SPINLOCK(sclp_lock);
  32
  33 /* Mask of events that we can send to the sclp interface. */
  34 static sccb_mask_t sclp_receive_mask;
  35
  36 /* Mask of events that we can receive from the sclp interface. */
  37 static sccb_mask_t sclp_send_mask;
  38
  39 /* List of registered event listeners and senders. */
  40 static struct list_head sclp_reg_list;
  41
  42 /* List of queued requests. */
  43 static struct list_head sclp_req_queue;
  44
  45 /* Data for read and and init requests. */
  46 static struct sclp_req sclp_read_req;
  47 static struct sclp_req sclp_init_req;
  48 static void *sclp_read_sccb;
  49 static struct init_sccb *sclp_init_sccb;
  50
  51 /* Suspend request */
  52 static DECLARE_COMPLETION(sclp_request_queue_flushed);
  53
  54 /* Number of console pages to allocate, used by sclp_con.c and sclp_vt220.c */
  55 int sclp_console_pages = SCLP_CONSOLE_PAGES;
  56 /* Flag to indicate if buffer pages are dropped on buffer full condition */
  57 int sclp_console_drop = 1;
  58 /* Number of times the console dropped buffer pages */
  59 unsigned long sclp_console_full;
  60
  61 static void sclp_suspend_req_cb(struct sclp_req *req, void *data)
  62 {
  63         complete(&sclp_request_queue_flushed);
  64 }
  65
  66 static int __init sclp_setup_console_pages(char *str)
  67 {
  68         int pages, rc;
  69
  70         rc = kstrtoint(str, 0, &pages);
  71         if (!rc && pages >= SCLP_CONSOLE_PAGES)
  72                 sclp_console_pages = pages;
  73         return 1;
  74 }
  75
  76 __setup("sclp_con_pages=", sclp_setup_console_pages);
  77
  78 static int __init sclp_setup_console_drop(char *str)
  79 {
  80         int drop, rc;
  81
  82         rc = kstrtoint(str, 0, &drop);
  83         if (!rc)
  84                 sclp_console_drop = drop;
  85         return 1;
  86 }
  87
  88 __setup("sclp_con_drop=", sclp_setup_console_drop);
  89
  90 static struct sclp_req sclp_suspend_req;
  91
  92 /* Timer for request retries. */
  93 static struct timer_list sclp_request_timer;
  94
  95 /* Timer for queued requests. */
  96 static struct timer_list sclp_queue_timer;
  97
  98 /* Internal state: is a request active at the sclp? */
  99 static volatile enum sclp_running_state_t {
 100         sclp_running_state_idle,
 101         sclp_running_state_running,
 102         sclp_running_state_reset_pending
 103 } sclp_running_state = sclp_running_state_idle;
 104
 105 /* Internal state: is a read request pending? */
 106 static volatile enum sclp_reading_state_t {
 107         sclp_reading_state_idle,
 108         sclp_reading_state_reading
 109 } sclp_reading_state = sclp_reading_state_idle;
 110
 111 /* Internal state: is the driver currently serving requests? */
 112 static volatile enum sclp_activation_state_t {
 113         sclp_activation_state_active,
 114         sclp_activation_state_deactivating,
 115         sclp_activation_state_inactive,
 116         sclp_activation_state_activating
 117 } sclp_activation_state = sclp_activation_state_active;
 118
 119 /* Internal state: is an init mask request pending? */
 120 static volatile enum sclp_mask_state_t {
 121         sclp_mask_state_idle,
 122         sclp_mask_state_initializing
 123 } sclp_mask_state = sclp_mask_state_idle;
 124
 125 /* Internal state: is the driver suspended? */
 126 static enum sclp_suspend_state_t {
 127         sclp_suspend_state_running,
 128         sclp_suspend_state_suspended,
 129 } sclp_suspend_state = sclp_suspend_state_running;
 130
 131 /* Maximum retry counts */
 132 #define SCLP_INIT_RETRY         3
 133 #define SCLP_MASK_RETRY         3
 134
 135 /* Timeout intervals in seconds.*/
 136 #define SCLP_BUSY_INTERVAL      10
 137 #define SCLP_RETRY_INTERVAL     30
 138
 139 static void sclp_request_timeout(bool force_restart);
 140 static void sclp_process_queue(void);
 141 static void __sclp_make_read_req(void);
 142 static int sclp_init_mask(int calculate);
 143 static int sclp_init(void);
 144
 145 static void
 146 __sclp_queue_read_req(void)
 147 {
 148         if (sclp_reading_state == sclp_reading_state_idle) {
 149                 sclp_reading_state = sclp_reading_state_reading;
 150                 __sclp_make_read_req();
 151                 /* Add request to head of queue */
 152                 list_add(&sclp_read_req.list, &sclp_req_queue);
 153         }
 154 }
 155
 156 /* Set up request retry timer. Called while sclp_lock is locked. */
 157 static inline void
 158 __sclp_set_request_timer(unsigned long time, void (*cb)(struct timer_list *))
 159 {
 160         del_timer(&sclp_request_timer);
 161         sclp_request_timer.function = cb;
 162         sclp_request_timer.expires = jiffies + time;
 163         add_timer(&sclp_request_timer);
 164 }
 165
 166 static void sclp_request_timeout_restart(struct timer_list *unused)
 167 {
 168         sclp_request_timeout(true);
 169 }
 170
 171 static void sclp_request_timeout_normal(struct timer_list *unused)
 172 {
 173         sclp_request_timeout(false);
 174 }
 175
 176 /* Request timeout handler. Restart the request queue. If force_restart,
 177  * force restart of running request. */
 178 static void sclp_request_timeout(bool force_restart)
 179 {
 180         unsigned long flags;
 181
 182         spin_lock_irqsave(&sclp_lock, flags);
 183         if (force_restart) {
 184                 if (sclp_running_state == sclp_running_state_running) {
 185                         /* Break running state and queue NOP read event request
 186                          * to get a defined interface state. */
 187                         __sclp_queue_read_req();
 188                         sclp_running_state = sclp_running_state_idle;
 189                 }
 190         } else {
 191                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 192                                          sclp_request_timeout_normal);
 193         }
 194         spin_unlock_irqrestore(&sclp_lock, flags);
 195         sclp_process_queue();
 196 }
 197
 198 /*
 199  * Returns the expire value in jiffies of the next pending request timeout,
 200  * if any. Needs to be called with sclp_lock.
 201  */
 202 static unsigned long __sclp_req_queue_find_next_timeout(void)
 203 {
 204         unsigned long expires_next = 0;
 205         struct sclp_req *req;
 206
 207         list_for_each_entry(req, &sclp_req_queue, list) {
 208                 if (!req->queue_expires)
 209                         continue;
 210                 if (!expires_next ||
 211                    (time_before(req->queue_expires, expires_next)))
 212                                 expires_next = req->queue_expires;
 213         }
 214         return expires_next;
 215 }
 216
 217 /*
 218  * Returns expired request, if any, and removes it from the list.
 219  */
 220 static struct sclp_req *__sclp_req_queue_remove_expired_req(void)
 221 {
 222         unsigned long flags, now;
 223         struct sclp_req *req;
 224
 225         spin_lock_irqsave(&sclp_lock, flags);
 226         now = jiffies;
 227         /* Don't need list_for_each_safe because we break out after list_del */
 228         list_for_each_entry(req, &sclp_req_queue, list) {
 229                 if (!req->queue_expires)
 230                         continue;
 231                 if (time_before_eq(req->queue_expires, now)) {
 232                         if (req->status == SCLP_REQ_QUEUED) {
 233                                 req->status = SCLP_REQ_QUEUED_TIMEOUT;
 234                                 list_del(&req->list);
 235                                 goto out;
 236                         }
 237                 }
 238         }
 239         req = NULL;
 240 out:
 241         spin_unlock_irqrestore(&sclp_lock, flags);
 242         return req;
 243 }
 244
 245 /*
 246  * Timeout handler for queued requests. Removes request from list and
 247  * invokes callback. This timer can be set per request in situations where
 248  * waiting too long would be harmful to the system, e.g. during SE reboot.
 249  */
 250 static void sclp_req_queue_timeout(struct timer_list *unused)
 251 {
 252         unsigned long flags, expires_next;
 253         struct sclp_req *req;
 254
 255         do {
 256                 req = __sclp_req_queue_remove_expired_req();
 257                 if (req && req->callback)
 258                         req->callback(req, req->callback_data);
 259         } while (req);
 260
 261         spin_lock_irqsave(&sclp_lock, flags);
 262         expires_next = __sclp_req_queue_find_next_timeout();
 263         if (expires_next)
 264                 mod_timer(&sclp_queue_timer, expires_next);
 265         spin_unlock_irqrestore(&sclp_lock, flags);
 266 }
 267
 268 /* Try to start a request. Return zero if the request was successfully
 269  * started or if it will be started at a later time. Return non-zero otherwise.
 270  * Called while sclp_lock is locked. */
 271 static int
 272 __sclp_start_request(struct sclp_req *req)
 273 {
 274         int rc;
 275
 276         if (sclp_running_state != sclp_running_state_idle)
 277                 return 0;
 278         del_timer(&sclp_request_timer);
 279         rc = sclp_service_call(req->command, req->sccb);
 280         req->start_count++;
 281
 282         if (rc == 0) {
 283                 /* Successfully started request */
 284                 req->status = SCLP_REQ_RUNNING;
 285                 sclp_running_state = sclp_running_state_running;
 286                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 287                                          sclp_request_timeout_restart);
 288                 return 0;
 289         } else if (rc == -EBUSY) {
 290                 /* Try again later */
 291                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 292                                          sclp_request_timeout_normal);
 293                 return 0;
 294         }
 295         /* Request failed */
 296         req->status = SCLP_REQ_FAILED;
 297         return rc;
 298 }
 299
 300 /* Try to start queued requests. */
 301 static void
 302 sclp_process_queue(void)
 303 {
 304         struct sclp_req *req;
 305         int rc;
 306         unsigned long flags;
 307
 308         spin_lock_irqsave(&sclp_lock, flags);
 309         if (sclp_running_state != sclp_running_state_idle) {
 310                 spin_unlock_irqrestore(&sclp_lock, flags);
 311                 return;
 312         }
 313         del_timer(&sclp_request_timer);
 314         while (!list_empty(&sclp_req_queue)) {
 315                 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
 316                 if (!req->sccb)
 317                         goto do_post;
 318                 rc = __sclp_start_request(req);
 319                 if (rc == 0)
 320                         break;
 321                 /* Request failed */
 322                 if (req->start_count > 1) {
 323                         /* Cannot abort already submitted request - could still
 324                          * be active at the SCLP */
 325                         __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 326                                                  sclp_request_timeout_normal);
 327                         break;
 328                 }
 329 do_post:
 330                 /* Post-processing for aborted request */
 331                 list_del(&req->list);
 332                 if (req->callback) {
 333                         spin_unlock_irqrestore(&sclp_lock, flags);
 334                         req->callback(req, req->callback_data);
 335                         spin_lock_irqsave(&sclp_lock, flags);
 336                 }
 337         }
 338         spin_unlock_irqrestore(&sclp_lock, flags);
 339 }
 340
 341 static int __sclp_can_add_request(struct sclp_req *req)
 342 {
 343         if (req == &sclp_suspend_req || req == &sclp_init_req)
 344                 return 1;
 345         if (sclp_suspend_state != sclp_suspend_state_running)
 346                 return 0;
 347         if (sclp_init_state != sclp_init_state_initialized)
 348                 return 0;
 349         if (sclp_activation_state != sclp_activation_state_active)
 350                 return 0;
 351         return 1;
 352 }
 353
 354 /* Queue a new request. Return zero on success, non-zero otherwise. */
 355 int
 356 sclp_add_request(struct sclp_req *req)
 357 {
 358         unsigned long flags;
 359         int rc;
 360
 361         spin_lock_irqsave(&sclp_lock, flags);
 362         if (!__sclp_can_add_request(req)) {
 363                 spin_unlock_irqrestore(&sclp_lock, flags);
 364                 return -EIO;
 365         }
 366         req->status = SCLP_REQ_QUEUED;
 367         req->start_count = 0;
 368         list_add_tail(&req->list, &sclp_req_queue);
 369         rc = 0;
 370         if (req->queue_timeout) {
 371                 req->queue_expires = jiffies + req->queue_timeout * HZ;
 372                 if (!timer_pending(&sclp_queue_timer) ||
 373                     time_after(sclp_queue_timer.expires, req->queue_expires))
 374                         mod_timer(&sclp_queue_timer, req->queue_expires);
 375         } else
 376                 req->queue_expires = 0;
 377         /* Start if request is first in list */
 378         if (sclp_running_state == sclp_running_state_idle &&
 379             req->list.prev == &sclp_req_queue) {
 380                 if (!req->sccb) {
 381                         list_del(&req->list);
 382                         rc = -ENODATA;
 383                         goto out;
 384                 }
 385                 rc = __sclp_start_request(req);
 386                 if (rc)
 387                         list_del(&req->list);
 388         }
 389 out:
 390         spin_unlock_irqrestore(&sclp_lock, flags);
 391         return rc;
 392 }
 393
 394 EXPORT_SYMBOL(sclp_add_request);
 395
 396 /* Dispatch events found in request buffer to registered listeners. Return 0
 397  * if all events were dispatched, non-zero otherwise. */
 398 static int
 399 sclp_dispatch_evbufs(struct sccb_header *sccb)
 400 {
 401         unsigned long flags;
 402         struct evbuf_header *evbuf;
 403         struct list_head *l;
 404         struct sclp_register *reg;
 405         int offset;
 406         int rc;
 407
 408         spin_lock_irqsave(&sclp_lock, flags);
 409         rc = 0;
 410         for (offset = sizeof(struct sccb_header); offset < sccb->length;
 411              offset += evbuf->length) {
 412                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 413                 /* Check for malformed hardware response */
 414                 if (evbuf->length == 0)
 415                         break;
 416                 /* Search for event handler */
 417                 reg = NULL;
 418                 list_for_each(l, &sclp_reg_list) {
 419                         reg = list_entry(l, struct sclp_register, list);
 420                         if (reg->receive_mask & SCLP_EVTYP_MASK(evbuf->type))
 421                                 break;
 422                         else
 423                                 reg = NULL;
 424                 }
 425                 if (reg && reg->receiver_fn) {
 426                         spin_unlock_irqrestore(&sclp_lock, flags);
 427                         reg->receiver_fn(evbuf);
 428                         spin_lock_irqsave(&sclp_lock, flags);
 429                 } else if (reg == NULL)
 430                         rc = -EOPNOTSUPP;
 431         }
 432         spin_unlock_irqrestore(&sclp_lock, flags);
 433         return rc;
 434 }
 435
 436 /* Read event data request callback. */
 437 static void
 438 sclp_read_cb(struct sclp_req *req, void *data)
 439 {
 440         unsigned long flags;
 441         struct sccb_header *sccb;
 442
 443         sccb = (struct sccb_header *) req->sccb;
 444         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 445             sccb->response_code == 0x220))
 446                 sclp_dispatch_evbufs(sccb);
 447         spin_lock_irqsave(&sclp_lock, flags);
 448         sclp_reading_state = sclp_reading_state_idle;
 449         spin_unlock_irqrestore(&sclp_lock, flags);
 450 }
 451
 452 /* Prepare read event data request. Called while sclp_lock is locked. */
 453 static void __sclp_make_read_req(void)
 454 {
 455         struct sccb_header *sccb;
 456
 457         sccb = (struct sccb_header *) sclp_read_sccb;
 458         clear_page(sccb);
 459         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 460         sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
 461         sclp_read_req.status = SCLP_REQ_QUEUED;
 462         sclp_read_req.start_count = 0;
 463         sclp_read_req.callback = sclp_read_cb;
 464         sclp_read_req.sccb = sccb;
 465         sccb->length = PAGE_SIZE;
 466         sccb->function_code = 0;
 467         sccb->control_mask[2] = 0x80;
 468 }
 469
 470 /* Search request list for request with matching sccb. Return request if found,
 471  * NULL otherwise. Called while sclp_lock is locked. */
 472 static inline struct sclp_req *
 473 __sclp_find_req(u32 sccb)
 474 {
 475         struct list_head *l;
 476         struct sclp_req *req;
 477
 478         list_for_each(l, &sclp_req_queue) {
 479                 req = list_entry(l, struct sclp_req, list);
 480                 if (sccb == (u32) (addr_t) req->sccb)
 481                                 return req;
 482         }
 483         return NULL;
 484 }
 485
 486 /* Handler for external interruption. Perform request post-processing.
 487  * Prepare read event data request if necessary. Start processing of next
 488  * request on queue. */
 489 static void sclp_interrupt_handler(struct ext_code ext_code,
 490                                    unsigned int param32, unsigned long param64)
 491 {
 492         struct sclp_req *req;
 493         u32 finished_sccb;
 494         u32 evbuf_pending;
 495
 496         inc_irq_stat(IRQEXT_SCP);
 497         spin_lock(&sclp_lock);
 498         finished_sccb = param32 & 0xfffffff8;
 499         evbuf_pending = param32 & 0x3;
 500         if (finished_sccb) {
 501                 del_timer(&sclp_request_timer);
 502                 sclp_running_state = sclp_running_state_reset_pending;
 503                 req = __sclp_find_req(finished_sccb);
 504                 if (req) {
 505                         /* Request post-processing */
 506                         list_del(&req->list);
 507                         req->status = SCLP_REQ_DONE;
 508                         if (req->callback) {
 509                                 spin_unlock(&sclp_lock);
 510                                 req->callback(req, req->callback_data);
 511                                 spin_lock(&sclp_lock);
 512                         }
 513                 }
 514                 sclp_running_state = sclp_running_state_idle;
 515         }
 516         if (evbuf_pending &&
 517             sclp_activation_state == sclp_activation_state_active)
 518                 __sclp_queue_read_req();
 519         spin_unlock(&sclp_lock);
 520         sclp_process_queue();
 521 }
 522
 523 /* Convert interval in jiffies to TOD ticks. */
 524 static inline u64
 525 sclp_tod_from_jiffies(unsigned long jiffies)
 526 {
 527         return (u64) (jiffies / HZ) << 32;
 528 }
 529
 530 /* Wait until a currently running request finished. Note: while this function
 531  * is running, no timers are served on the calling CPU. */
 532 void
 533 sclp_sync_wait(void)
 534 {
 535         unsigned long long old_tick;
 536         unsigned long flags;
 537         unsigned long cr0, cr0_sync;
 538         u64 timeout;
 539         int irq_context;
 540
 541         /* We'll be disabling timer interrupts, so we need a custom timeout
 542          * mechanism */
 543         timeout = 0;
 544         if (timer_pending(&sclp_request_timer)) {
 545                 /* Get timeout TOD value */
 546                 timeout = get_tod_clock_fast() +
 547                           sclp_tod_from_jiffies(sclp_request_timer.expires -
 548                                                 jiffies);
 549         }
 550         local_irq_save(flags);
 551         /* Prevent bottom half from executing once we force interrupts open */
 552         irq_context = in_interrupt();
 553         if (!irq_context)
 554                 local_bh_disable();
 555         /* Enable service-signal interruption, disable timer interrupts */
 556         old_tick = local_tick_disable();
 557         trace_hardirqs_on();
 558         __ctl_store(cr0, 0, 0);
 559         cr0_sync = cr0 & ~CR0_IRQ_SUBCLASS_MASK;
 560         cr0_sync |= 1UL << (63 - 54);
 561         __ctl_load(cr0_sync, 0, 0);
 562         __arch_local_irq_stosm(0x01);
 563         /* Loop until driver state indicates finished request */
 564         while (sclp_running_state != sclp_running_state_idle) {
 565                 /* Check for expired request timer */
 566                 if (timer_pending(&sclp_request_timer) &&
 567                     get_tod_clock_fast() > timeout &&
 568                     del_timer(&sclp_request_timer))
 569                         sclp_request_timer.function(&sclp_request_timer);
 570                 cpu_relax();
 571         }
 572         local_irq_disable();
 573         __ctl_load(cr0, 0, 0);
 574         if (!irq_context)
 575                 _local_bh_enable();
 576         local_tick_enable(old_tick);
 577         local_irq_restore(flags);
 578 }
 579 EXPORT_SYMBOL(sclp_sync_wait);
 580
 581 /* Dispatch changes in send and receive mask to registered listeners. */
 582 static void
 583 sclp_dispatch_state_change(void)
 584 {
 585         struct list_head *l;
 586         struct sclp_register *reg;
 587         unsigned long flags;
 588         sccb_mask_t receive_mask;
 589         sccb_mask_t send_mask;
 590
 591         do {
 592                 spin_lock_irqsave(&sclp_lock, flags);
 593                 reg = NULL;
 594                 list_for_each(l, &sclp_reg_list) {
 595                         reg = list_entry(l, struct sclp_register, list);
 596                         receive_mask = reg->send_mask & sclp_receive_mask;
 597                         send_mask = reg->receive_mask & sclp_send_mask;
 598                         if (reg->sclp_receive_mask != receive_mask ||
 599                             reg->sclp_send_mask != send_mask) {
 600                                 reg->sclp_receive_mask = receive_mask;
 601                                 reg->sclp_send_mask = send_mask;
 602                                 break;
 603                         } else
 604                                 reg = NULL;
 605                 }
 606                 spin_unlock_irqrestore(&sclp_lock, flags);
 607                 if (reg && reg->state_change_fn)
 608                         reg->state_change_fn(reg);
 609         } while (reg);
 610 }
 611
 612 struct sclp_statechangebuf {
 613         struct evbuf_header     header;
 614         u8              validity_sclp_active_facility_mask : 1;
 615         u8              validity_sclp_receive_mask : 1;
 616         u8              validity_sclp_send_mask : 1;
 617         u8              validity_read_data_function_mask : 1;
 618         u16             _zeros : 12;
 619         u16             mask_length;
 620         u64             sclp_active_facility_mask;
 621         u8              masks[2 * 1021 + 4];    /* variable length */
 622         /*
 623          * u8           sclp_receive_mask[mask_length];
 624          * u8           sclp_send_mask[mask_length];
 625          * u32          read_data_function_mask;
 626          */
 627 } __attribute__((packed));
 628
 629
 630 /* State change event callback. Inform listeners of changes. */
 631 static void
 632 sclp_state_change_cb(struct evbuf_header *evbuf)
 633 {
 634         unsigned long flags;
 635         struct sclp_statechangebuf *scbuf;
 636
 637         BUILD_BUG_ON(sizeof(struct sclp_statechangebuf) > PAGE_SIZE);
 638
 639         scbuf = (struct sclp_statechangebuf *) evbuf;
 640         spin_lock_irqsave(&sclp_lock, flags);
 641         if (scbuf->validity_sclp_receive_mask)
 642                 sclp_receive_mask = sccb_get_recv_mask(scbuf);
 643         if (scbuf->validity_sclp_send_mask)
 644                 sclp_send_mask = sccb_get_send_mask(scbuf);
 645         spin_unlock_irqrestore(&sclp_lock, flags);
 646         if (scbuf->validity_sclp_active_facility_mask)
 647                 sclp.facilities = scbuf->sclp_active_facility_mask;
 648         sclp_dispatch_state_change();
 649 }
 650
 651 static struct sclp_register sclp_state_change_event = {
 652         .receive_mask = EVTYP_STATECHANGE_MASK,
 653         .receiver_fn = sclp_state_change_cb
 654 };
 655
 656 /* Calculate receive and send mask of currently registered listeners.
 657  * Called while sclp_lock is locked. */
 658 static inline void
 659 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 660 {
 661         struct list_head *l;
 662         struct sclp_register *t;
 663
 664         *receive_mask = 0;
 665         *send_mask = 0;
 666         list_for_each(l, &sclp_reg_list) {
 667                 t = list_entry(l, struct sclp_register, list);
 668                 *receive_mask |= t->receive_mask;
 669                 *send_mask |= t->send_mask;
 670         }
 671 }
 672
 673 /* Register event listener. Return 0 on success, non-zero otherwise. */
 674 int
 675 sclp_register(struct sclp_register *reg)
 676 {
 677         unsigned long flags;
 678         sccb_mask_t receive_mask;
 679         sccb_mask_t send_mask;
 680         int rc;
 681
 682         rc = sclp_init();
 683         if (rc)
 684                 return rc;
 685         spin_lock_irqsave(&sclp_lock, flags);
 686         /* Check event mask for collisions */
 687         __sclp_get_mask(&receive_mask, &send_mask);
 688         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 689                 spin_unlock_irqrestore(&sclp_lock, flags);
 690                 return -EBUSY;
 691         }
 692         /* Trigger initial state change callback */
 693         reg->sclp_receive_mask = 0;
 694         reg->sclp_send_mask = 0;
 695         reg->pm_event_posted = 0;
 696         list_add(&reg->list, &sclp_reg_list);
 697         spin_unlock_irqrestore(&sclp_lock, flags);
 698         rc = sclp_init_mask(1);
 699         if (rc) {
 700                 spin_lock_irqsave(&sclp_lock, flags);
 701                 list_del(&reg->list);
 702                 spin_unlock_irqrestore(&sclp_lock, flags);
 703         }
 704         return rc;
 705 }
 706
 707 EXPORT_SYMBOL(sclp_register);
 708
 709 /* Unregister event listener. */
 710 void
 711 sclp_unregister(struct sclp_register *reg)
 712 {
 713         unsigned long flags;
 714
 715         spin_lock_irqsave(&sclp_lock, flags);
 716         list_del(&reg->list);
 717         spin_unlock_irqrestore(&sclp_lock, flags);
 718         sclp_init_mask(1);
 719 }
 720
 721 EXPORT_SYMBOL(sclp_unregister);
 722
 723 /* Remove event buffers which are marked processed. Return the number of
 724  * remaining event buffers. */
 725 int
 726 sclp_remove_processed(struct sccb_header *sccb)
 727 {
 728         struct evbuf_header *evbuf;
 729         int unprocessed;
 730         u16 remaining;
 731
 732         evbuf = (struct evbuf_header *) (sccb + 1);
 733         unprocessed = 0;
 734         remaining = sccb->length - sizeof(struct sccb_header);
 735         while (remaining > 0) {
 736                 remaining -= evbuf->length;
 737                 if (evbuf->flags & 0x80) {
 738                         sccb->length -= evbuf->length;
 739                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 740                                remaining);
 741                 } else {
 742                         unprocessed++;
 743                         evbuf = (struct evbuf_header *)
 744                                         ((addr_t) evbuf + evbuf->length);
 745                 }
 746         }
 747         return unprocessed;
 748 }
 749
 750 EXPORT_SYMBOL(sclp_remove_processed);
 751
 752 /* Prepare init mask request. Called while sclp_lock is locked. */
 753 static inline void
 754 __sclp_make_init_req(sccb_mask_t receive_mask, sccb_mask_t send_mask)
 755 {
 756         struct init_sccb *sccb = sclp_init_sccb;
 757
 758         clear_page(sccb);
 759         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 760         sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 761         sclp_init_req.status = SCLP_REQ_FILLED;
 762         sclp_init_req.start_count = 0;
 763         sclp_init_req.callback = NULL;
 764         sclp_init_req.callback_data = NULL;
 765         sclp_init_req.sccb = sccb;
 766         sccb->header.length = sizeof(*sccb);
 767         if (sclp_mask_compat_mode)
 768                 sccb->mask_length = SCLP_MASK_SIZE_COMPAT;
 769         else
 770                 sccb->mask_length = sizeof(sccb_mask_t);
 771         sccb_set_recv_mask(sccb, receive_mask);
 772         sccb_set_send_mask(sccb, send_mask);
 773         sccb_set_sclp_recv_mask(sccb, 0);
 774         sccb_set_sclp_send_mask(sccb, 0);
 775 }
 776
 777 /* Start init mask request. If calculate is non-zero, calculate the mask as
 778  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 779  * success, non-zero otherwise. */
 780 static int
 781 sclp_init_mask(int calculate)
 782 {
 783         unsigned long flags;
 784         struct init_sccb *sccb = sclp_init_sccb;
 785         sccb_mask_t receive_mask;
 786         sccb_mask_t send_mask;
 787         int retry;
 788         int rc;
 789         unsigned long wait;
 790
 791         spin_lock_irqsave(&sclp_lock, flags);
 792         /* Check if interface is in appropriate state */
 793         if (sclp_mask_state != sclp_mask_state_idle) {
 794                 spin_unlock_irqrestore(&sclp_lock, flags);
 795                 return -EBUSY;
 796         }
 797         if (sclp_activation_state == sclp_activation_state_inactive) {
 798                 spin_unlock_irqrestore(&sclp_lock, flags);
 799                 return -EINVAL;
 800         }
 801         sclp_mask_state = sclp_mask_state_initializing;
 802         /* Determine mask */
 803         if (calculate)
 804                 __sclp_get_mask(&receive_mask, &send_mask);
 805         else {
 806                 receive_mask = 0;
 807                 send_mask = 0;
 808         }
 809         rc = -EIO;
 810         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 811                 /* Prepare request */
 812                 __sclp_make_init_req(receive_mask, send_mask);
 813                 spin_unlock_irqrestore(&sclp_lock, flags);
 814                 if (sclp_add_request(&sclp_init_req)) {
 815                         /* Try again later */
 816                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 817                         while (time_before(jiffies, wait))
 818                                 sclp_sync_wait();
 819                         spin_lock_irqsave(&sclp_lock, flags);
 820                         continue;
 821                 }
 822                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 823                        sclp_init_req.status != SCLP_REQ_FAILED)
 824                         sclp_sync_wait();
 825                 spin_lock_irqsave(&sclp_lock, flags);
 826                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 827                     sccb->header.response_code == 0x20) {
 828                         /* Successful request */
 829                         if (calculate) {
 830                                 sclp_receive_mask = sccb_get_sclp_recv_mask(sccb);
 831                                 sclp_send_mask = sccb_get_sclp_send_mask(sccb);
 832                         } else {
 833                                 sclp_receive_mask = 0;
 834                                 sclp_send_mask = 0;
 835                         }
 836                         spin_unlock_irqrestore(&sclp_lock, flags);
 837                         sclp_dispatch_state_change();
 838                         spin_lock_irqsave(&sclp_lock, flags);
 839                         rc = 0;
 840                         break;
 841                 }
 842         }
 843         sclp_mask_state = sclp_mask_state_idle;
 844         spin_unlock_irqrestore(&sclp_lock, flags);
 845         return rc;
 846 }
 847
 848 /* Deactivate SCLP interface. On success, new requests will be rejected,
 849  * events will no longer be dispatched. Return 0 on success, non-zero
 850  * otherwise. */
 851 int
 852 sclp_deactivate(void)
 853 {
 854         unsigned long flags;
 855         int rc;
 856
 857         spin_lock_irqsave(&sclp_lock, flags);
 858         /* Deactivate can only be called when active */
 859         if (sclp_activation_state != sclp_activation_state_active) {
 860                 spin_unlock_irqrestore(&sclp_lock, flags);
 861                 return -EINVAL;
 862         }
 863         sclp_activation_state = sclp_activation_state_deactivating;
 864         spin_unlock_irqrestore(&sclp_lock, flags);
 865         rc = sclp_init_mask(0);
 866         spin_lock_irqsave(&sclp_lock, flags);
 867         if (rc == 0)
 868                 sclp_activation_state = sclp_activation_state_inactive;
 869         else
 870                 sclp_activation_state = sclp_activation_state_active;
 871         spin_unlock_irqrestore(&sclp_lock, flags);
 872         return rc;
 873 }
 874
 875 EXPORT_SYMBOL(sclp_deactivate);
 876
 877 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 878  * requests will be accepted, events will be dispatched again. Return 0 on
 879  * success, non-zero otherwise. */
 880 int
 881 sclp_reactivate(void)
 882 {
 883         unsigned long flags;
 884         int rc;
 885
 886         spin_lock_irqsave(&sclp_lock, flags);
 887         /* Reactivate can only be called when inactive */
 888         if (sclp_activation_state != sclp_activation_state_inactive) {
 889                 spin_unlock_irqrestore(&sclp_lock, flags);
 890                 return -EINVAL;
 891         }
 892         sclp_activation_state = sclp_activation_state_activating;
 893         spin_unlock_irqrestore(&sclp_lock, flags);
 894         rc = sclp_init_mask(1);
 895         spin_lock_irqsave(&sclp_lock, flags);
 896         if (rc == 0)
 897                 sclp_activation_state = sclp_activation_state_active;
 898         else
 899                 sclp_activation_state = sclp_activation_state_inactive;
 900         spin_unlock_irqrestore(&sclp_lock, flags);
 901         return rc;
 902 }
 903
 904 EXPORT_SYMBOL(sclp_reactivate);
 905
 906 /* Handler for external interruption used during initialization. Modify
 907  * request state to done. */
 908 static void sclp_check_handler(struct ext_code ext_code,
 909                                unsigned int param32, unsigned long param64)
 910 {
 911         u32 finished_sccb;
 912
 913         inc_irq_stat(IRQEXT_SCP);
 914         finished_sccb = param32 & 0xfffffff8;
 915         /* Is this the interrupt we are waiting for? */
 916         if (finished_sccb == 0)
 917                 return;
 918         if (finished_sccb != (u32) (addr_t) sclp_init_sccb)
 919                 panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
 920                       finished_sccb);
 921         spin_lock(&sclp_lock);
 922         if (sclp_running_state == sclp_running_state_running) {
 923                 sclp_init_req.status = SCLP_REQ_DONE;
 924                 sclp_running_state = sclp_running_state_idle;
 925         }
 926         spin_unlock(&sclp_lock);
 927 }
 928
 929 /* Initial init mask request timed out. Modify request state to failed. */
 930 static void
 931 sclp_check_timeout(struct timer_list *unused)
 932 {
 933         unsigned long flags;
 934
 935         spin_lock_irqsave(&sclp_lock, flags);
 936         if (sclp_running_state == sclp_running_state_running) {
 937                 sclp_init_req.status = SCLP_REQ_FAILED;
 938                 sclp_running_state = sclp_running_state_idle;
 939         }
 940         spin_unlock_irqrestore(&sclp_lock, flags);
 941 }
 942
 943 /* Perform a check of the SCLP interface. Return zero if the interface is
 944  * available and there are no pending requests from a previous instance.
 945  * Return non-zero otherwise. */
 946 static int
 947 sclp_check_interface(void)
 948 {
 949         struct init_sccb *sccb;
 950         unsigned long flags;
 951         int retry;
 952         int rc;
 953
 954         spin_lock_irqsave(&sclp_lock, flags);
 955         /* Prepare init mask command */
 956         rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
 957         if (rc) {
 958                 spin_unlock_irqrestore(&sclp_lock, flags);
 959                 return rc;
 960         }
 961         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 962                 __sclp_make_init_req(0, 0);
 963                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 964                 rc = sclp_service_call(sclp_init_req.command, sccb);
 965                 if (rc == -EIO)
 966                         break;
 967                 sclp_init_req.status = SCLP_REQ_RUNNING;
 968                 sclp_running_state = sclp_running_state_running;
 969                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 970                                          sclp_check_timeout);
 971                 spin_unlock_irqrestore(&sclp_lock, flags);
 972                 /* Enable service-signal interruption - needs to happen
 973                  * with IRQs enabled. */
 974                 irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
 975                 /* Wait for signal from interrupt or timeout */
 976                 sclp_sync_wait();
 977                 /* Disable service-signal interruption - needs to happen
 978                  * with IRQs enabled. */
 979                 irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
 980                 spin_lock_irqsave(&sclp_lock, flags);
 981                 del_timer(&sclp_request_timer);
 982                 rc = -EBUSY;
 983                 if (sclp_init_req.status == SCLP_REQ_DONE) {
 984                         if (sccb->header.response_code == 0x20) {
 985                                 rc = 0;
 986                                 break;
 987                         } else if (sccb->header.response_code == 0x74f0) {
 988                                 if (!sclp_mask_compat_mode) {
 989                                         sclp_mask_compat_mode = true;
 990                                         retry = 0;
 991                                 }
 992                         }
 993                 }
 994         }
 995         unregister_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
 996         spin_unlock_irqrestore(&sclp_lock, flags);
 997         return rc;
 998 }
 999
1000 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
1001  * events from interfering with rebooted system. */
1002 static int
1003 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
1004 {
1005         sclp_deactivate();
1006         return NOTIFY_DONE;
1007 }
1008
1009 static struct notifier_block sclp_reboot_notifier = {
1010         .notifier_call = sclp_reboot_event
1011 };
1012
1013 /*
1014  * Suspend/resume SCLP notifier implementation
1015  */
1016
1017 static void sclp_pm_event(enum sclp_pm_event sclp_pm_event, int rollback)
1018 {
1019         struct sclp_register *reg;
1020         unsigned long flags;
1021
1022         if (!rollback) {
1023                 spin_lock_irqsave(&sclp_lock, flags);
1024                 list_for_each_entry(reg, &sclp_reg_list, list)
1025                         reg->pm_event_posted = 0;
1026                 spin_unlock_irqrestore(&sclp_lock, flags);
1027         }
1028         do {
1029                 spin_lock_irqsave(&sclp_lock, flags);
1030                 list_for_each_entry(reg, &sclp_reg_list, list) {
1031                         if (rollback && reg->pm_event_posted)
1032                                 goto found;
1033                         if (!rollback && !reg->pm_event_posted)
1034                                 goto found;
1035                 }
1036                 spin_unlock_irqrestore(&sclp_lock, flags);
1037                 return;
1038 found:
1039                 spin_unlock_irqrestore(&sclp_lock, flags);
1040                 if (reg->pm_event_fn)
1041                         reg->pm_event_fn(reg, sclp_pm_event);
1042                 reg->pm_event_posted = rollback ? 0 : 1;
1043         } while (1);
1044 }
1045
1046 /*
1047  * Susend/resume callbacks for platform device
1048  */
1049
1050 static int sclp_freeze(struct device *dev)
1051 {
1052         unsigned long flags;
1053         int rc;
1054
1055         sclp_pm_event(SCLP_PM_EVENT_FREEZE, 0);
1056
1057         spin_lock_irqsave(&sclp_lock, flags);
1058         sclp_suspend_state = sclp_suspend_state_suspended;
1059         spin_unlock_irqrestore(&sclp_lock, flags);
1060
1061         /* Init supend data */
1062         memset(&sclp_suspend_req, 0, sizeof(sclp_suspend_req));
1063         sclp_suspend_req.callback = sclp_suspend_req_cb;
1064         sclp_suspend_req.status = SCLP_REQ_FILLED;
1065         init_completion(&sclp_request_queue_flushed);
1066
1067         rc = sclp_add_request(&sclp_suspend_req);
1068         if (rc == 0)
1069                 wait_for_completion(&sclp_request_queue_flushed);
1070         else if (rc != -ENODATA)
1071                 goto fail_thaw;
1072
1073         rc = sclp_deactivate();
1074         if (rc)
1075                 goto fail_thaw;
1076         return 0;
1077
1078 fail_thaw:
1079         spin_lock_irqsave(&sclp_lock, flags);
1080         sclp_suspend_state = sclp_suspend_state_running;
1081         spin_unlock_irqrestore(&sclp_lock, flags);
1082         sclp_pm_event(SCLP_PM_EVENT_THAW, 1);
1083         return rc;
1084 }
1085
1086 static int sclp_undo_suspend(enum sclp_pm_event event)
1087 {
1088         unsigned long flags;
1089         int rc;
1090
1091         rc = sclp_reactivate();
1092         if (rc)
1093                 return rc;
1094
1095         spin_lock_irqsave(&sclp_lock, flags);
1096         sclp_suspend_state = sclp_suspend_state_running;
1097         spin_unlock_irqrestore(&sclp_lock, flags);
1098
1099         sclp_pm_event(event, 0);
1100         return 0;
1101 }
1102
1103 static int sclp_thaw(struct device *dev)
1104 {
1105         return sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1106 }
1107
1108 static int sclp_restore(struct device *dev)
1109 {
1110         return sclp_undo_suspend(SCLP_PM_EVENT_RESTORE);
1111 }
1112
1113 static const struct dev_pm_ops sclp_pm_ops = {
1114         .freeze         = sclp_freeze,
1115         .thaw           = sclp_thaw,
1116         .restore        = sclp_restore,
1117 };
1118
1119 static ssize_t con_pages_show(struct device_driver *dev, char *buf)
1120 {
1121         return sprintf(buf, "%i\n", sclp_console_pages);
1122 }
1123
1124 static DRIVER_ATTR_RO(con_pages);
1125
1126 static ssize_t con_drop_show(struct device_driver *dev, char *buf)
1127 {
1128         return sprintf(buf, "%i\n", sclp_console_drop);
1129 }
1130
1131 static DRIVER_ATTR_RO(con_drop);
1132
1133 static ssize_t con_full_show(struct device_driver *dev, char *buf)
1134 {
1135         return sprintf(buf, "%lu\n", sclp_console_full);
1136 }
1137
1138 static DRIVER_ATTR_RO(con_full);
1139
1140 static struct attribute *sclp_drv_attrs[] = {
1141         &driver_attr_con_pages.attr,
1142         &driver_attr_con_drop.attr,
1143         &driver_attr_con_full.attr,
1144         NULL,
1145 };
1146 static struct attribute_group sclp_drv_attr_group = {
1147         .attrs = sclp_drv_attrs,
1148 };
1149 static const struct attribute_group *sclp_drv_attr_groups[] = {
1150         &sclp_drv_attr_group,
1151         NULL,
1152 };
1153
1154 static struct platform_driver sclp_pdrv = {
1155         .driver = {
1156                 .name   = "sclp",
1157                 .pm     = &sclp_pm_ops,
1158                 .groups = sclp_drv_attr_groups,
1159         },
1160 };
1161
1162 static struct platform_device *sclp_pdev;
1163
1164 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
1165  * otherwise. */
1166 static int
1167 sclp_init(void)
1168 {
1169         unsigned long flags;
1170         int rc = 0;
1171
1172         spin_lock_irqsave(&sclp_lock, flags);
1173         /* Check for previous or running initialization */
1174         if (sclp_init_state != sclp_init_state_uninitialized)
1175                 goto fail_unlock;
1176         sclp_init_state = sclp_init_state_initializing;
1177         sclp_read_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
1178         sclp_init_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
1179         BUG_ON(!sclp_read_sccb || !sclp_init_sccb);
1180         /* Set up variables */
1181         INIT_LIST_HEAD(&sclp_req_queue);
1182         INIT_LIST_HEAD(&sclp_reg_list);
1183         list_add(&sclp_state_change_event.list, &sclp_reg_list);
1184         timer_setup(&sclp_request_timer, NULL, 0);
1185         timer_setup(&sclp_queue_timer, sclp_req_queue_timeout, 0);
1186         /* Check interface */
1187         spin_unlock_irqrestore(&sclp_lock, flags);
1188         rc = sclp_check_interface();
1189         spin_lock_irqsave(&sclp_lock, flags);
1190         if (rc)
1191                 goto fail_init_state_uninitialized;
1192         /* Register reboot handler */
1193         rc = register_reboot_notifier(&sclp_reboot_notifier);
1194         if (rc)
1195                 goto fail_init_state_uninitialized;
1196         /* Register interrupt handler */
1197         rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_interrupt_handler);
1198         if (rc)
1199                 goto fail_unregister_reboot_notifier;
1200         sclp_init_state = sclp_init_state_initialized;
1201         spin_unlock_irqrestore(&sclp_lock, flags);
1202         /* Enable service-signal external interruption - needs to happen with
1203          * IRQs enabled. */
1204         irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1205         sclp_init_mask(1);
1206         return 0;
1207
1208 fail_unregister_reboot_notifier:
1209         unregister_reboot_notifier(&sclp_reboot_notifier);
1210 fail_init_state_uninitialized:
1211         sclp_init_state = sclp_init_state_uninitialized;
1212         free_page((unsigned long) sclp_read_sccb);
1213         free_page((unsigned long) sclp_init_sccb);
1214 fail_unlock:
1215         spin_unlock_irqrestore(&sclp_lock, flags);
1216         return rc;
1217 }
1218
1219 /*
1220  * SCLP panic notifier: If we are suspended, we thaw SCLP in order to be able
1221  * to print the panic message.
1222  */
1223 static int sclp_panic_notify(struct notifier_block *self,
1224                              unsigned long event, void *data)
1225 {
1226         if (sclp_suspend_state == sclp_suspend_state_suspended)
1227                 sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1228         return NOTIFY_OK;
1229 }
1230
1231 static struct notifier_block sclp_on_panic_nb = {
1232         .notifier_call = sclp_panic_notify,
1233         .priority = SCLP_PANIC_PRIO,
1234 };
1235
1236 static __init int sclp_initcall(void)
1237 {
1238         int rc;
1239
1240         rc = platform_driver_register(&sclp_pdrv);
1241         if (rc)
1242                 return rc;
1243
1244         sclp_pdev = platform_device_register_simple("sclp", -1, NULL, 0);
1245         rc = PTR_ERR_OR_ZERO(sclp_pdev);
1246         if (rc)
1247                 goto fail_platform_driver_unregister;
1248
1249         rc = atomic_notifier_chain_register(&panic_notifier_list,
1250                                             &sclp_on_panic_nb);
1251         if (rc)
1252                 goto fail_platform_device_unregister;
1253
1254         return sclp_init();
1255
1256 fail_platform_device_unregister:
1257         platform_device_unregister(sclp_pdev);
1258 fail_platform_driver_unregister:
1259         platform_driver_unregister(&sclp_pdrv);
1260         return rc;
1261 }
1262
1263 arch_initcall(sclp_initcall);