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 char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  49 static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  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 & (1 << (32 - 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         sccb_mask_t     sclp_receive_mask;
 622         sccb_mask_t     sclp_send_mask;
 623         u32             read_data_function_mask;
 624 } __attribute__((packed));
 625
 626
 627 /* State change event callback. Inform listeners of changes. */
 628 static void
 629 sclp_state_change_cb(struct evbuf_header *evbuf)
 630 {
 631         unsigned long flags;
 632         struct sclp_statechangebuf *scbuf;
 633
 634         scbuf = (struct sclp_statechangebuf *) evbuf;
 635         if (scbuf->mask_length != sizeof(sccb_mask_t))
 636                 return;
 637         spin_lock_irqsave(&sclp_lock, flags);
 638         if (scbuf->validity_sclp_receive_mask)
 639                 sclp_receive_mask = scbuf->sclp_receive_mask;
 640         if (scbuf->validity_sclp_send_mask)
 641                 sclp_send_mask = scbuf->sclp_send_mask;
 642         spin_unlock_irqrestore(&sclp_lock, flags);
 643         if (scbuf->validity_sclp_active_facility_mask)
 644                 sclp.facilities = scbuf->sclp_active_facility_mask;
 645         sclp_dispatch_state_change();
 646 }
 647
 648 static struct sclp_register sclp_state_change_event = {
 649         .receive_mask = EVTYP_STATECHANGE_MASK,
 650         .receiver_fn = sclp_state_change_cb
 651 };
 652
 653 /* Calculate receive and send mask of currently registered listeners.
 654  * Called while sclp_lock is locked. */
 655 static inline void
 656 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 657 {
 658         struct list_head *l;
 659         struct sclp_register *t;
 660
 661         *receive_mask = 0;
 662         *send_mask = 0;
 663         list_for_each(l, &sclp_reg_list) {
 664                 t = list_entry(l, struct sclp_register, list);
 665                 *receive_mask |= t->receive_mask;
 666                 *send_mask |= t->send_mask;
 667         }
 668 }
 669
 670 /* Register event listener. Return 0 on success, non-zero otherwise. */
 671 int
 672 sclp_register(struct sclp_register *reg)
 673 {
 674         unsigned long flags;
 675         sccb_mask_t receive_mask;
 676         sccb_mask_t send_mask;
 677         int rc;
 678
 679         rc = sclp_init();
 680         if (rc)
 681                 return rc;
 682         spin_lock_irqsave(&sclp_lock, flags);
 683         /* Check event mask for collisions */
 684         __sclp_get_mask(&receive_mask, &send_mask);
 685         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 686                 spin_unlock_irqrestore(&sclp_lock, flags);
 687                 return -EBUSY;
 688         }
 689         /* Trigger initial state change callback */
 690         reg->sclp_receive_mask = 0;
 691         reg->sclp_send_mask = 0;
 692         reg->pm_event_posted = 0;
 693         list_add(&reg->list, &sclp_reg_list);
 694         spin_unlock_irqrestore(&sclp_lock, flags);
 695         rc = sclp_init_mask(1);
 696         if (rc) {
 697                 spin_lock_irqsave(&sclp_lock, flags);
 698                 list_del(&reg->list);
 699                 spin_unlock_irqrestore(&sclp_lock, flags);
 700         }
 701         return rc;
 702 }
 703
 704 EXPORT_SYMBOL(sclp_register);
 705
 706 /* Unregister event listener. */
 707 void
 708 sclp_unregister(struct sclp_register *reg)
 709 {
 710         unsigned long flags;
 711
 712         spin_lock_irqsave(&sclp_lock, flags);
 713         list_del(&reg->list);
 714         spin_unlock_irqrestore(&sclp_lock, flags);
 715         sclp_init_mask(1);
 716 }
 717
 718 EXPORT_SYMBOL(sclp_unregister);
 719
 720 /* Remove event buffers which are marked processed. Return the number of
 721  * remaining event buffers. */
 722 int
 723 sclp_remove_processed(struct sccb_header *sccb)
 724 {
 725         struct evbuf_header *evbuf;
 726         int unprocessed;
 727         u16 remaining;
 728
 729         evbuf = (struct evbuf_header *) (sccb + 1);
 730         unprocessed = 0;
 731         remaining = sccb->length - sizeof(struct sccb_header);
 732         while (remaining > 0) {
 733                 remaining -= evbuf->length;
 734                 if (evbuf->flags & 0x80) {
 735                         sccb->length -= evbuf->length;
 736                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 737                                remaining);
 738                 } else {
 739                         unprocessed++;
 740                         evbuf = (struct evbuf_header *)
 741                                         ((addr_t) evbuf + evbuf->length);
 742                 }
 743         }
 744         return unprocessed;
 745 }
 746
 747 EXPORT_SYMBOL(sclp_remove_processed);
 748
 749 /* Prepare init mask request. Called while sclp_lock is locked. */
 750 static inline void
 751 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 752 {
 753         struct init_sccb *sccb;
 754
 755         sccb = (struct init_sccb *) sclp_init_sccb;
 756         clear_page(sccb);
 757         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 758         sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 759         sclp_init_req.status = SCLP_REQ_FILLED;
 760         sclp_init_req.start_count = 0;
 761         sclp_init_req.callback = NULL;
 762         sclp_init_req.callback_data = NULL;
 763         sclp_init_req.sccb = sccb;
 764         sccb->header.length = sizeof(struct init_sccb);
 765         sccb->mask_length = sizeof(sccb_mask_t);
 766         sccb->receive_mask = receive_mask;
 767         sccb->send_mask = send_mask;
 768         sccb->sclp_receive_mask = 0;
 769         sccb->sclp_send_mask = 0;
 770 }
 771
 772 /* Start init mask request. If calculate is non-zero, calculate the mask as
 773  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 774  * success, non-zero otherwise. */
 775 static int
 776 sclp_init_mask(int calculate)
 777 {
 778         unsigned long flags;
 779         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 780         sccb_mask_t receive_mask;
 781         sccb_mask_t send_mask;
 782         int retry;
 783         int rc;
 784         unsigned long wait;
 785
 786         spin_lock_irqsave(&sclp_lock, flags);
 787         /* Check if interface is in appropriate state */
 788         if (sclp_mask_state != sclp_mask_state_idle) {
 789                 spin_unlock_irqrestore(&sclp_lock, flags);
 790                 return -EBUSY;
 791         }
 792         if (sclp_activation_state == sclp_activation_state_inactive) {
 793                 spin_unlock_irqrestore(&sclp_lock, flags);
 794                 return -EINVAL;
 795         }
 796         sclp_mask_state = sclp_mask_state_initializing;
 797         /* Determine mask */
 798         if (calculate)
 799                 __sclp_get_mask(&receive_mask, &send_mask);
 800         else {
 801                 receive_mask = 0;
 802                 send_mask = 0;
 803         }
 804         rc = -EIO;
 805         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 806                 /* Prepare request */
 807                 __sclp_make_init_req(receive_mask, send_mask);
 808                 spin_unlock_irqrestore(&sclp_lock, flags);
 809                 if (sclp_add_request(&sclp_init_req)) {
 810                         /* Try again later */
 811                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 812                         while (time_before(jiffies, wait))
 813                                 sclp_sync_wait();
 814                         spin_lock_irqsave(&sclp_lock, flags);
 815                         continue;
 816                 }
 817                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 818                        sclp_init_req.status != SCLP_REQ_FAILED)
 819                         sclp_sync_wait();
 820                 spin_lock_irqsave(&sclp_lock, flags);
 821                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 822                     sccb->header.response_code == 0x20) {
 823                         /* Successful request */
 824                         if (calculate) {
 825                                 sclp_receive_mask = sccb->sclp_receive_mask;
 826                                 sclp_send_mask = sccb->sclp_send_mask;
 827                         } else {
 828                                 sclp_receive_mask = 0;
 829                                 sclp_send_mask = 0;
 830                         }
 831                         spin_unlock_irqrestore(&sclp_lock, flags);
 832                         sclp_dispatch_state_change();
 833                         spin_lock_irqsave(&sclp_lock, flags);
 834                         rc = 0;
 835                         break;
 836                 }
 837         }
 838         sclp_mask_state = sclp_mask_state_idle;
 839         spin_unlock_irqrestore(&sclp_lock, flags);
 840         return rc;
 841 }
 842
 843 /* Deactivate SCLP interface. On success, new requests will be rejected,
 844  * events will no longer be dispatched. Return 0 on success, non-zero
 845  * otherwise. */
 846 int
 847 sclp_deactivate(void)
 848 {
 849         unsigned long flags;
 850         int rc;
 851
 852         spin_lock_irqsave(&sclp_lock, flags);
 853         /* Deactivate can only be called when active */
 854         if (sclp_activation_state != sclp_activation_state_active) {
 855                 spin_unlock_irqrestore(&sclp_lock, flags);
 856                 return -EINVAL;
 857         }
 858         sclp_activation_state = sclp_activation_state_deactivating;
 859         spin_unlock_irqrestore(&sclp_lock, flags);
 860         rc = sclp_init_mask(0);
 861         spin_lock_irqsave(&sclp_lock, flags);
 862         if (rc == 0)
 863                 sclp_activation_state = sclp_activation_state_inactive;
 864         else
 865                 sclp_activation_state = sclp_activation_state_active;
 866         spin_unlock_irqrestore(&sclp_lock, flags);
 867         return rc;
 868 }
 869
 870 EXPORT_SYMBOL(sclp_deactivate);
 871
 872 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 873  * requests will be accepted, events will be dispatched again. Return 0 on
 874  * success, non-zero otherwise. */
 875 int
 876 sclp_reactivate(void)
 877 {
 878         unsigned long flags;
 879         int rc;
 880
 881         spin_lock_irqsave(&sclp_lock, flags);
 882         /* Reactivate can only be called when inactive */
 883         if (sclp_activation_state != sclp_activation_state_inactive) {
 884                 spin_unlock_irqrestore(&sclp_lock, flags);
 885                 return -EINVAL;
 886         }
 887         sclp_activation_state = sclp_activation_state_activating;
 888         spin_unlock_irqrestore(&sclp_lock, flags);
 889         rc = sclp_init_mask(1);
 890         spin_lock_irqsave(&sclp_lock, flags);
 891         if (rc == 0)
 892                 sclp_activation_state = sclp_activation_state_active;
 893         else
 894                 sclp_activation_state = sclp_activation_state_inactive;
 895         spin_unlock_irqrestore(&sclp_lock, flags);
 896         return rc;
 897 }
 898
 899 EXPORT_SYMBOL(sclp_reactivate);
 900
 901 /* Handler for external interruption used during initialization. Modify
 902  * request state to done. */
 903 static void sclp_check_handler(struct ext_code ext_code,
 904                                unsigned int param32, unsigned long param64)
 905 {
 906         u32 finished_sccb;
 907
 908         inc_irq_stat(IRQEXT_SCP);
 909         finished_sccb = param32 & 0xfffffff8;
 910         /* Is this the interrupt we are waiting for? */
 911         if (finished_sccb == 0)
 912                 return;
 913         if (finished_sccb != (u32) (addr_t) sclp_init_sccb)
 914                 panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
 915                       finished_sccb);
 916         spin_lock(&sclp_lock);
 917         if (sclp_running_state == sclp_running_state_running) {
 918                 sclp_init_req.status = SCLP_REQ_DONE;
 919                 sclp_running_state = sclp_running_state_idle;
 920         }
 921         spin_unlock(&sclp_lock);
 922 }
 923
 924 /* Initial init mask request timed out. Modify request state to failed. */
 925 static void
 926 sclp_check_timeout(struct timer_list *unused)
 927 {
 928         unsigned long flags;
 929
 930         spin_lock_irqsave(&sclp_lock, flags);
 931         if (sclp_running_state == sclp_running_state_running) {
 932                 sclp_init_req.status = SCLP_REQ_FAILED;
 933                 sclp_running_state = sclp_running_state_idle;
 934         }
 935         spin_unlock_irqrestore(&sclp_lock, flags);
 936 }
 937
 938 /* Perform a check of the SCLP interface. Return zero if the interface is
 939  * available and there are no pending requests from a previous instance.
 940  * Return non-zero otherwise. */
 941 static int
 942 sclp_check_interface(void)
 943 {
 944         struct init_sccb *sccb;
 945         unsigned long flags;
 946         int retry;
 947         int rc;
 948
 949         spin_lock_irqsave(&sclp_lock, flags);
 950         /* Prepare init mask command */
 951         rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
 952         if (rc) {
 953                 spin_unlock_irqrestore(&sclp_lock, flags);
 954                 return rc;
 955         }
 956         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 957                 __sclp_make_init_req(0, 0);
 958                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 959                 rc = sclp_service_call(sclp_init_req.command, sccb);
 960                 if (rc == -EIO)
 961                         break;
 962                 sclp_init_req.status = SCLP_REQ_RUNNING;
 963                 sclp_running_state = sclp_running_state_running;
 964                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 965                                          sclp_check_timeout);
 966                 spin_unlock_irqrestore(&sclp_lock, flags);
 967                 /* Enable service-signal interruption - needs to happen
 968                  * with IRQs enabled. */
 969                 irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
 970                 /* Wait for signal from interrupt or timeout */
 971                 sclp_sync_wait();
 972                 /* Disable service-signal interruption - needs to happen
 973                  * with IRQs enabled. */
 974                 irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
 975                 spin_lock_irqsave(&sclp_lock, flags);
 976                 del_timer(&sclp_request_timer);
 977                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 978                     sccb->header.response_code == 0x20) {
 979                         rc = 0;
 980                         break;
 981                 } else
 982                         rc = -EBUSY;
 983         }
 984         unregister_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
 985         spin_unlock_irqrestore(&sclp_lock, flags);
 986         return rc;
 987 }
 988
 989 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 990  * events from interfering with rebooted system. */
 991 static int
 992 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 993 {
 994         sclp_deactivate();
 995         return NOTIFY_DONE;
 996 }
 997
 998 static struct notifier_block sclp_reboot_notifier = {
 999         .notifier_call = sclp_reboot_event
1000 };
1001
1002 /*
1003  * Suspend/resume SCLP notifier implementation
1004  */
1005
1006 static void sclp_pm_event(enum sclp_pm_event sclp_pm_event, int rollback)
1007 {
1008         struct sclp_register *reg;
1009         unsigned long flags;
1010
1011         if (!rollback) {
1012                 spin_lock_irqsave(&sclp_lock, flags);
1013                 list_for_each_entry(reg, &sclp_reg_list, list)
1014                         reg->pm_event_posted = 0;
1015                 spin_unlock_irqrestore(&sclp_lock, flags);
1016         }
1017         do {
1018                 spin_lock_irqsave(&sclp_lock, flags);
1019                 list_for_each_entry(reg, &sclp_reg_list, list) {
1020                         if (rollback && reg->pm_event_posted)
1021                                 goto found;
1022                         if (!rollback && !reg->pm_event_posted)
1023                                 goto found;
1024                 }
1025                 spin_unlock_irqrestore(&sclp_lock, flags);
1026                 return;
1027 found:
1028                 spin_unlock_irqrestore(&sclp_lock, flags);
1029                 if (reg->pm_event_fn)
1030                         reg->pm_event_fn(reg, sclp_pm_event);
1031                 reg->pm_event_posted = rollback ? 0 : 1;
1032         } while (1);
1033 }
1034
1035 /*
1036  * Susend/resume callbacks for platform device
1037  */
1038
1039 static int sclp_freeze(struct device *dev)
1040 {
1041         unsigned long flags;
1042         int rc;
1043
1044         sclp_pm_event(SCLP_PM_EVENT_FREEZE, 0);
1045
1046         spin_lock_irqsave(&sclp_lock, flags);
1047         sclp_suspend_state = sclp_suspend_state_suspended;
1048         spin_unlock_irqrestore(&sclp_lock, flags);
1049
1050         /* Init supend data */
1051         memset(&sclp_suspend_req, 0, sizeof(sclp_suspend_req));
1052         sclp_suspend_req.callback = sclp_suspend_req_cb;
1053         sclp_suspend_req.status = SCLP_REQ_FILLED;
1054         init_completion(&sclp_request_queue_flushed);
1055
1056         rc = sclp_add_request(&sclp_suspend_req);
1057         if (rc == 0)
1058                 wait_for_completion(&sclp_request_queue_flushed);
1059         else if (rc != -ENODATA)
1060                 goto fail_thaw;
1061
1062         rc = sclp_deactivate();
1063         if (rc)
1064                 goto fail_thaw;
1065         return 0;
1066
1067 fail_thaw:
1068         spin_lock_irqsave(&sclp_lock, flags);
1069         sclp_suspend_state = sclp_suspend_state_running;
1070         spin_unlock_irqrestore(&sclp_lock, flags);
1071         sclp_pm_event(SCLP_PM_EVENT_THAW, 1);
1072         return rc;
1073 }
1074
1075 static int sclp_undo_suspend(enum sclp_pm_event event)
1076 {
1077         unsigned long flags;
1078         int rc;
1079
1080         rc = sclp_reactivate();
1081         if (rc)
1082                 return rc;
1083
1084         spin_lock_irqsave(&sclp_lock, flags);
1085         sclp_suspend_state = sclp_suspend_state_running;
1086         spin_unlock_irqrestore(&sclp_lock, flags);
1087
1088         sclp_pm_event(event, 0);
1089         return 0;
1090 }
1091
1092 static int sclp_thaw(struct device *dev)
1093 {
1094         return sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1095 }
1096
1097 static int sclp_restore(struct device *dev)
1098 {
1099         return sclp_undo_suspend(SCLP_PM_EVENT_RESTORE);
1100 }
1101
1102 static const struct dev_pm_ops sclp_pm_ops = {
1103         .freeze         = sclp_freeze,
1104         .thaw           = sclp_thaw,
1105         .restore        = sclp_restore,
1106 };
1107
1108 static ssize_t con_pages_show(struct device_driver *dev, char *buf)
1109 {
1110         return sprintf(buf, "%i\n", sclp_console_pages);
1111 }
1112
1113 static DRIVER_ATTR_RO(con_pages);
1114
1115 static ssize_t con_drop_show(struct device_driver *dev, char *buf)
1116 {
1117         return sprintf(buf, "%i\n", sclp_console_drop);
1118 }
1119
1120 static DRIVER_ATTR_RO(con_drop);
1121
1122 static ssize_t con_full_show(struct device_driver *dev, char *buf)
1123 {
1124         return sprintf(buf, "%lu\n", sclp_console_full);
1125 }
1126
1127 static DRIVER_ATTR_RO(con_full);
1128
1129 static struct attribute *sclp_drv_attrs[] = {
1130         &driver_attr_con_pages.attr,
1131         &driver_attr_con_drop.attr,
1132         &driver_attr_con_full.attr,
1133         NULL,
1134 };
1135 static struct attribute_group sclp_drv_attr_group = {
1136         .attrs = sclp_drv_attrs,
1137 };
1138 static const struct attribute_group *sclp_drv_attr_groups[] = {
1139         &sclp_drv_attr_group,
1140         NULL,
1141 };
1142
1143 static struct platform_driver sclp_pdrv = {
1144         .driver = {
1145                 .name   = "sclp",
1146                 .pm     = &sclp_pm_ops,
1147                 .groups = sclp_drv_attr_groups,
1148         },
1149 };
1150
1151 static struct platform_device *sclp_pdev;
1152
1153 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
1154  * otherwise. */
1155 static int
1156 sclp_init(void)
1157 {
1158         unsigned long flags;
1159         int rc = 0;
1160
1161         spin_lock_irqsave(&sclp_lock, flags);
1162         /* Check for previous or running initialization */
1163         if (sclp_init_state != sclp_init_state_uninitialized)
1164                 goto fail_unlock;
1165         sclp_init_state = sclp_init_state_initializing;
1166         /* Set up variables */
1167         INIT_LIST_HEAD(&sclp_req_queue);
1168         INIT_LIST_HEAD(&sclp_reg_list);
1169         list_add(&sclp_state_change_event.list, &sclp_reg_list);
1170         timer_setup(&sclp_request_timer, NULL, 0);
1171         timer_setup(&sclp_queue_timer, sclp_req_queue_timeout, 0);
1172         /* Check interface */
1173         spin_unlock_irqrestore(&sclp_lock, flags);
1174         rc = sclp_check_interface();
1175         spin_lock_irqsave(&sclp_lock, flags);
1176         if (rc)
1177                 goto fail_init_state_uninitialized;
1178         /* Register reboot handler */
1179         rc = register_reboot_notifier(&sclp_reboot_notifier);
1180         if (rc)
1181                 goto fail_init_state_uninitialized;
1182         /* Register interrupt handler */
1183         rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_interrupt_handler);
1184         if (rc)
1185                 goto fail_unregister_reboot_notifier;
1186         sclp_init_state = sclp_init_state_initialized;
1187         spin_unlock_irqrestore(&sclp_lock, flags);
1188         /* Enable service-signal external interruption - needs to happen with
1189          * IRQs enabled. */
1190         irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1191         sclp_init_mask(1);
1192         return 0;
1193
1194 fail_unregister_reboot_notifier:
1195         unregister_reboot_notifier(&sclp_reboot_notifier);
1196 fail_init_state_uninitialized:
1197         sclp_init_state = sclp_init_state_uninitialized;
1198 fail_unlock:
1199         spin_unlock_irqrestore(&sclp_lock, flags);
1200         return rc;
1201 }
1202
1203 /*
1204  * SCLP panic notifier: If we are suspended, we thaw SCLP in order to be able
1205  * to print the panic message.
1206  */
1207 static int sclp_panic_notify(struct notifier_block *self,
1208                              unsigned long event, void *data)
1209 {
1210         if (sclp_suspend_state == sclp_suspend_state_suspended)
1211                 sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1212         return NOTIFY_OK;
1213 }
1214
1215 static struct notifier_block sclp_on_panic_nb = {
1216         .notifier_call = sclp_panic_notify,
1217         .priority = SCLP_PANIC_PRIO,
1218 };
1219
1220 static __init int sclp_initcall(void)
1221 {
1222         int rc;
1223
1224         rc = platform_driver_register(&sclp_pdrv);
1225         if (rc)
1226                 return rc;
1227
1228         sclp_pdev = platform_device_register_simple("sclp", -1, NULL, 0);
1229         rc = PTR_ERR_OR_ZERO(sclp_pdev);
1230         if (rc)
1231                 goto fail_platform_driver_unregister;
1232
1233         rc = atomic_notifier_chain_register(&panic_notifier_list,
1234                                             &sclp_on_panic_nb);
1235         if (rc)
1236                 goto fail_platform_device_unregister;
1237
1238         return sclp_init();
1239
1240 fail_platform_device_unregister:
1241         platform_device_unregister(sclp_pdev);
1242 fail_platform_driver_unregister:
1243         platform_driver_unregister(&sclp_pdrv);
1244         return rc;
1245 }
1246
1247 arch_initcall(sclp_initcall);