drivers/s390/char/sclp.c

   1 /*
   2  * core function to access sclp interface
   3  *
   4  * Copyright IBM Corp. 1999, 2009
   5  *
   6  * Author(s): Martin Peschke <mpeschke@de.ibm.com>
   7  *            Martin Schwidefsky <schwidefsky@de.ibm.com>
   8  */
   9
  10 #include <linux/kernel_stat.h>
  11 #include <linux/module.h>
  12 #include <linux/err.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/timer.h>
  16 #include <linux/reboot.h>
  17 #include <linux/jiffies.h>
  18 #include <linux/init.h>
  19 #include <linux/suspend.h>
  20 #include <linux/completion.h>
  21 #include <linux/platform_device.h>
  22 #include <asm/types.h>
  23 #include <asm/irq.h>
  24
  25 #include "sclp.h"
  26
  27 #define SCLP_HEADER             "sclp: "
  28
  29 /* Lock to protect internal data consistency. */
  30 static DEFINE_SPINLOCK(sclp_lock);
  31
  32 /* Mask of events that we can send to the sclp interface. */
  33 static sccb_mask_t sclp_receive_mask;
  34
  35 /* Mask of events that we can receive from the sclp interface. */
  36 static sccb_mask_t sclp_send_mask;
  37
  38 /* List of registered event listeners and senders. */
  39 static struct list_head sclp_reg_list;
  40
  41 /* List of queued requests. */
  42 static struct list_head sclp_req_queue;
  43
  44 /* Data for read and and init requests. */
  45 static struct sclp_req sclp_read_req;
  46 static struct sclp_req sclp_init_req;
  47 static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  48 static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  49
  50 /* Suspend request */
  51 static DECLARE_COMPLETION(sclp_request_queue_flushed);
  52
  53 /* Number of console pages to allocate, used by sclp_con.c and sclp_vt220.c */
  54 int sclp_console_pages = SCLP_CONSOLE_PAGES;
  55 /* Flag to indicate if buffer pages are dropped on buffer full condition */
  56 int sclp_console_drop = 1;
  57 /* Number of times the console dropped buffer pages */
  58 unsigned long sclp_console_full;
  59
  60 static void sclp_suspend_req_cb(struct sclp_req *req, void *data)
  61 {
  62         complete(&sclp_request_queue_flushed);
  63 }
  64
  65 static int __init sclp_setup_console_pages(char *str)
  66 {
  67         int pages, rc;
  68
  69         rc = kstrtoint(str, 0, &pages);
  70         if (!rc && pages >= SCLP_CONSOLE_PAGES)
  71                 sclp_console_pages = pages;
  72         return 1;
  73 }
  74
  75 __setup("sclp_con_pages=", sclp_setup_console_pages);
  76
  77 static int __init sclp_setup_console_drop(char *str)
  78 {
  79         int drop, rc;
  80
  81         rc = kstrtoint(str, 0, &drop);
  82         if (!rc)
  83                 sclp_console_drop = drop;
  84         return 1;
  85 }
  86
  87 __setup("sclp_con_drop=", sclp_setup_console_drop);
  88
  89 static struct sclp_req sclp_suspend_req;
  90
  91 /* Timer for request retries. */
  92 static struct timer_list sclp_request_timer;
  93
  94 /* Timer for queued requests. */
  95 static struct timer_list sclp_queue_timer;
  96
  97 /* Internal state: is the driver initialized? */
  98 static volatile enum sclp_init_state_t {
  99         sclp_init_state_uninitialized,
 100         sclp_init_state_initializing,
 101         sclp_init_state_initialized
 102 } sclp_init_state = sclp_init_state_uninitialized;
 103
 104 /* Internal state: is a request active at the sclp? */
 105 static volatile enum sclp_running_state_t {
 106         sclp_running_state_idle,
 107         sclp_running_state_running,
 108         sclp_running_state_reset_pending
 109 } sclp_running_state = sclp_running_state_idle;
 110
 111 /* Internal state: is a read request pending? */
 112 static volatile enum sclp_reading_state_t {
 113         sclp_reading_state_idle,
 114         sclp_reading_state_reading
 115 } sclp_reading_state = sclp_reading_state_idle;
 116
 117 /* Internal state: is the driver currently serving requests? */
 118 static volatile enum sclp_activation_state_t {
 119         sclp_activation_state_active,
 120         sclp_activation_state_deactivating,
 121         sclp_activation_state_inactive,
 122         sclp_activation_state_activating
 123 } sclp_activation_state = sclp_activation_state_active;
 124
 125 /* Internal state: is an init mask request pending? */
 126 static volatile enum sclp_mask_state_t {
 127         sclp_mask_state_idle,
 128         sclp_mask_state_initializing
 129 } sclp_mask_state = sclp_mask_state_idle;
 130
 131 /* Internal state: is the driver suspended? */
 132 static enum sclp_suspend_state_t {
 133         sclp_suspend_state_running,
 134         sclp_suspend_state_suspended,
 135 } sclp_suspend_state = sclp_suspend_state_running;
 136
 137 /* Maximum retry counts */
 138 #define SCLP_INIT_RETRY         3
 139 #define SCLP_MASK_RETRY         3
 140
 141 /* Timeout intervals in seconds.*/
 142 #define SCLP_BUSY_INTERVAL      10
 143 #define SCLP_RETRY_INTERVAL     30
 144
 145 static void sclp_process_queue(void);
 146 static void __sclp_make_read_req(void);
 147 static int sclp_init_mask(int calculate);
 148 static int sclp_init(void);
 149
 150 /* Perform service call. Return 0 on success, non-zero otherwise. */
 151 int
 152 sclp_service_call(sclp_cmdw_t command, void *sccb)
 153 {
 154         int cc = 4; /* Initialize for program check handling */
 155
 156         asm volatile(
 157                 "0:     .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
 158                 "1:     ipm     %0\n"
 159                 "       srl     %0,28\n"
 160                 "2:\n"
 161                 EX_TABLE(0b, 2b)
 162                 EX_TABLE(1b, 2b)
 163                 : "+&d" (cc) : "d" (command), "a" (__pa(sccb))
 164                 : "cc", "memory");
 165         if (cc == 4)
 166                 return -EINVAL;
 167         if (cc == 3)
 168                 return -EIO;
 169         if (cc == 2)
 170                 return -EBUSY;
 171         return 0;
 172 }
 173
 174
 175 static void
 176 __sclp_queue_read_req(void)
 177 {
 178         if (sclp_reading_state == sclp_reading_state_idle) {
 179                 sclp_reading_state = sclp_reading_state_reading;
 180                 __sclp_make_read_req();
 181                 /* Add request to head of queue */
 182                 list_add(&sclp_read_req.list, &sclp_req_queue);
 183         }
 184 }
 185
 186 /* Set up request retry timer. Called while sclp_lock is locked. */
 187 static inline void
 188 __sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
 189                          unsigned long data)
 190 {
 191         del_timer(&sclp_request_timer);
 192         sclp_request_timer.function = function;
 193         sclp_request_timer.data = data;
 194         sclp_request_timer.expires = jiffies + time;
 195         add_timer(&sclp_request_timer);
 196 }
 197
 198 /* Request timeout handler. Restart the request queue. If DATA is non-zero,
 199  * force restart of running request. */
 200 static void
 201 sclp_request_timeout(unsigned long data)
 202 {
 203         unsigned long flags;
 204
 205         spin_lock_irqsave(&sclp_lock, flags);
 206         if (data) {
 207                 if (sclp_running_state == sclp_running_state_running) {
 208                         /* Break running state and queue NOP read event request
 209                          * to get a defined interface state. */
 210                         __sclp_queue_read_req();
 211                         sclp_running_state = sclp_running_state_idle;
 212                 }
 213         } else {
 214                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 215                                          sclp_request_timeout, 0);
 216         }
 217         spin_unlock_irqrestore(&sclp_lock, flags);
 218         sclp_process_queue();
 219 }
 220
 221 /*
 222  * Returns the expire value in jiffies of the next pending request timeout,
 223  * if any. Needs to be called with sclp_lock.
 224  */
 225 static unsigned long __sclp_req_queue_find_next_timeout(void)
 226 {
 227         unsigned long expires_next = 0;
 228         struct sclp_req *req;
 229
 230         list_for_each_entry(req, &sclp_req_queue, list) {
 231                 if (!req->queue_expires)
 232                         continue;
 233                 if (!expires_next ||
 234                    (time_before(req->queue_expires, expires_next)))
 235                                 expires_next = req->queue_expires;
 236         }
 237         return expires_next;
 238 }
 239
 240 /*
 241  * Returns expired request, if any, and removes it from the list.
 242  */
 243 static struct sclp_req *__sclp_req_queue_remove_expired_req(void)
 244 {
 245         unsigned long flags, now;
 246         struct sclp_req *req;
 247
 248         spin_lock_irqsave(&sclp_lock, flags);
 249         now = jiffies;
 250         /* Don't need list_for_each_safe because we break out after list_del */
 251         list_for_each_entry(req, &sclp_req_queue, list) {
 252                 if (!req->queue_expires)
 253                         continue;
 254                 if (time_before_eq(req->queue_expires, now)) {
 255                         if (req->status == SCLP_REQ_QUEUED) {
 256                                 req->status = SCLP_REQ_QUEUED_TIMEOUT;
 257                                 list_del(&req->list);
 258                                 goto out;
 259                         }
 260                 }
 261         }
 262         req = NULL;
 263 out:
 264         spin_unlock_irqrestore(&sclp_lock, flags);
 265         return req;
 266 }
 267
 268 /*
 269  * Timeout handler for queued requests. Removes request from list and
 270  * invokes callback. This timer can be set per request in situations where
 271  * waiting too long would be harmful to the system, e.g. during SE reboot.
 272  */
 273 static void sclp_req_queue_timeout(unsigned long data)
 274 {
 275         unsigned long flags, expires_next;
 276         struct sclp_req *req;
 277
 278         do {
 279                 req = __sclp_req_queue_remove_expired_req();
 280                 if (req && req->callback)
 281                         req->callback(req, req->callback_data);
 282         } while (req);
 283
 284         spin_lock_irqsave(&sclp_lock, flags);
 285         expires_next = __sclp_req_queue_find_next_timeout();
 286         if (expires_next)
 287                 mod_timer(&sclp_queue_timer, expires_next);
 288         spin_unlock_irqrestore(&sclp_lock, flags);
 289 }
 290
 291 /* Try to start a request. Return zero if the request was successfully
 292  * started or if it will be started at a later time. Return non-zero otherwise.
 293  * Called while sclp_lock is locked. */
 294 static int
 295 __sclp_start_request(struct sclp_req *req)
 296 {
 297         int rc;
 298
 299         if (sclp_running_state != sclp_running_state_idle)
 300                 return 0;
 301         del_timer(&sclp_request_timer);
 302         rc = sclp_service_call(req->command, req->sccb);
 303         req->start_count++;
 304
 305         if (rc == 0) {
 306                 /* Successfully started request */
 307                 req->status = SCLP_REQ_RUNNING;
 308                 sclp_running_state = sclp_running_state_running;
 309                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 310                                          sclp_request_timeout, 1);
 311                 return 0;
 312         } else if (rc == -EBUSY) {
 313                 /* Try again later */
 314                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 315                                          sclp_request_timeout, 0);
 316                 return 0;
 317         }
 318         /* Request failed */
 319         req->status = SCLP_REQ_FAILED;
 320         return rc;
 321 }
 322
 323 /* Try to start queued requests. */
 324 static void
 325 sclp_process_queue(void)
 326 {
 327         struct sclp_req *req;
 328         int rc;
 329         unsigned long flags;
 330
 331         spin_lock_irqsave(&sclp_lock, flags);
 332         if (sclp_running_state != sclp_running_state_idle) {
 333                 spin_unlock_irqrestore(&sclp_lock, flags);
 334                 return;
 335         }
 336         del_timer(&sclp_request_timer);
 337         while (!list_empty(&sclp_req_queue)) {
 338                 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
 339                 if (!req->sccb)
 340                         goto do_post;
 341                 rc = __sclp_start_request(req);
 342                 if (rc == 0)
 343                         break;
 344                 /* Request failed */
 345                 if (req->start_count > 1) {
 346                         /* Cannot abort already submitted request - could still
 347                          * be active at the SCLP */
 348                         __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 349                                                  sclp_request_timeout, 0);
 350                         break;
 351                 }
 352 do_post:
 353                 /* Post-processing for aborted request */
 354                 list_del(&req->list);
 355                 if (req->callback) {
 356                         spin_unlock_irqrestore(&sclp_lock, flags);
 357                         req->callback(req, req->callback_data);
 358                         spin_lock_irqsave(&sclp_lock, flags);
 359                 }
 360         }
 361         spin_unlock_irqrestore(&sclp_lock, flags);
 362 }
 363
 364 static int __sclp_can_add_request(struct sclp_req *req)
 365 {
 366         if (req == &sclp_suspend_req || req == &sclp_init_req)
 367                 return 1;
 368         if (sclp_suspend_state != sclp_suspend_state_running)
 369                 return 0;
 370         if (sclp_init_state != sclp_init_state_initialized)
 371                 return 0;
 372         if (sclp_activation_state != sclp_activation_state_active)
 373                 return 0;
 374         return 1;
 375 }
 376
 377 /* Queue a new request. Return zero on success, non-zero otherwise. */
 378 int
 379 sclp_add_request(struct sclp_req *req)
 380 {
 381         unsigned long flags;
 382         int rc;
 383
 384         spin_lock_irqsave(&sclp_lock, flags);
 385         if (!__sclp_can_add_request(req)) {
 386                 spin_unlock_irqrestore(&sclp_lock, flags);
 387                 return -EIO;
 388         }
 389         req->status = SCLP_REQ_QUEUED;
 390         req->start_count = 0;
 391         list_add_tail(&req->list, &sclp_req_queue);
 392         rc = 0;
 393         if (req->queue_timeout) {
 394                 req->queue_expires = jiffies + req->queue_timeout * HZ;
 395                 if (!timer_pending(&sclp_queue_timer) ||
 396                     time_after(sclp_queue_timer.expires, req->queue_expires))
 397                         mod_timer(&sclp_queue_timer, req->queue_expires);
 398         } else
 399                 req->queue_expires = 0;
 400         /* Start if request is first in list */
 401         if (sclp_running_state == sclp_running_state_idle &&
 402             req->list.prev == &sclp_req_queue) {
 403                 if (!req->sccb) {
 404                         list_del(&req->list);
 405                         rc = -ENODATA;
 406                         goto out;
 407                 }
 408                 rc = __sclp_start_request(req);
 409                 if (rc)
 410                         list_del(&req->list);
 411         }
 412 out:
 413         spin_unlock_irqrestore(&sclp_lock, flags);
 414         return rc;
 415 }
 416
 417 EXPORT_SYMBOL(sclp_add_request);
 418
 419 /* Dispatch events found in request buffer to registered listeners. Return 0
 420  * if all events were dispatched, non-zero otherwise. */
 421 static int
 422 sclp_dispatch_evbufs(struct sccb_header *sccb)
 423 {
 424         unsigned long flags;
 425         struct evbuf_header *evbuf;
 426         struct list_head *l;
 427         struct sclp_register *reg;
 428         int offset;
 429         int rc;
 430
 431         spin_lock_irqsave(&sclp_lock, flags);
 432         rc = 0;
 433         for (offset = sizeof(struct sccb_header); offset < sccb->length;
 434              offset += evbuf->length) {
 435                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 436                 /* Check for malformed hardware response */
 437                 if (evbuf->length == 0)
 438                         break;
 439                 /* Search for event handler */
 440                 reg = NULL;
 441                 list_for_each(l, &sclp_reg_list) {
 442                         reg = list_entry(l, struct sclp_register, list);
 443                         if (reg->receive_mask & (1 << (32 - evbuf->type)))
 444                                 break;
 445                         else
 446                                 reg = NULL;
 447                 }
 448                 if (reg && reg->receiver_fn) {
 449                         spin_unlock_irqrestore(&sclp_lock, flags);
 450                         reg->receiver_fn(evbuf);
 451                         spin_lock_irqsave(&sclp_lock, flags);
 452                 } else if (reg == NULL)
 453                         rc = -EOPNOTSUPP;
 454         }
 455         spin_unlock_irqrestore(&sclp_lock, flags);
 456         return rc;
 457 }
 458
 459 /* Read event data request callback. */
 460 static void
 461 sclp_read_cb(struct sclp_req *req, void *data)
 462 {
 463         unsigned long flags;
 464         struct sccb_header *sccb;
 465
 466         sccb = (struct sccb_header *) req->sccb;
 467         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 468             sccb->response_code == 0x220))
 469                 sclp_dispatch_evbufs(sccb);
 470         spin_lock_irqsave(&sclp_lock, flags);
 471         sclp_reading_state = sclp_reading_state_idle;
 472         spin_unlock_irqrestore(&sclp_lock, flags);
 473 }
 474
 475 /* Prepare read event data request. Called while sclp_lock is locked. */
 476 static void __sclp_make_read_req(void)
 477 {
 478         struct sccb_header *sccb;
 479
 480         sccb = (struct sccb_header *) sclp_read_sccb;
 481         clear_page(sccb);
 482         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 483         sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
 484         sclp_read_req.status = SCLP_REQ_QUEUED;
 485         sclp_read_req.start_count = 0;
 486         sclp_read_req.callback = sclp_read_cb;
 487         sclp_read_req.sccb = sccb;
 488         sccb->length = PAGE_SIZE;
 489         sccb->function_code = 0;
 490         sccb->control_mask[2] = 0x80;
 491 }
 492
 493 /* Search request list for request with matching sccb. Return request if found,
 494  * NULL otherwise. Called while sclp_lock is locked. */
 495 static inline struct sclp_req *
 496 __sclp_find_req(u32 sccb)
 497 {
 498         struct list_head *l;
 499         struct sclp_req *req;
 500
 501         list_for_each(l, &sclp_req_queue) {
 502                 req = list_entry(l, struct sclp_req, list);
 503                 if (sccb == (u32) (addr_t) req->sccb)
 504                                 return req;
 505         }
 506         return NULL;
 507 }
 508
 509 /* Handler for external interruption. Perform request post-processing.
 510  * Prepare read event data request if necessary. Start processing of next
 511  * request on queue. */
 512 static void sclp_interrupt_handler(struct ext_code ext_code,
 513                                    unsigned int param32, unsigned long param64)
 514 {
 515         struct sclp_req *req;
 516         u32 finished_sccb;
 517         u32 evbuf_pending;
 518
 519         inc_irq_stat(IRQEXT_SCP);
 520         spin_lock(&sclp_lock);
 521         finished_sccb = param32 & 0xfffffff8;
 522         evbuf_pending = param32 & 0x3;
 523         if (finished_sccb) {
 524                 del_timer(&sclp_request_timer);
 525                 sclp_running_state = sclp_running_state_reset_pending;
 526                 req = __sclp_find_req(finished_sccb);
 527                 if (req) {
 528                         /* Request post-processing */
 529                         list_del(&req->list);
 530                         req->status = SCLP_REQ_DONE;
 531                         if (req->callback) {
 532                                 spin_unlock(&sclp_lock);
 533                                 req->callback(req, req->callback_data);
 534                                 spin_lock(&sclp_lock);
 535                         }
 536                 }
 537                 sclp_running_state = sclp_running_state_idle;
 538         }
 539         if (evbuf_pending &&
 540             sclp_activation_state == sclp_activation_state_active)
 541                 __sclp_queue_read_req();
 542         spin_unlock(&sclp_lock);
 543         sclp_process_queue();
 544 }
 545
 546 /* Convert interval in jiffies to TOD ticks. */
 547 static inline u64
 548 sclp_tod_from_jiffies(unsigned long jiffies)
 549 {
 550         return (u64) (jiffies / HZ) << 32;
 551 }
 552
 553 /* Wait until a currently running request finished. Note: while this function
 554  * is running, no timers are served on the calling CPU. */
 555 void
 556 sclp_sync_wait(void)
 557 {
 558         unsigned long long old_tick;
 559         unsigned long flags;
 560         unsigned long cr0, cr0_sync;
 561         u64 timeout;
 562         int irq_context;
 563
 564         /* We'll be disabling timer interrupts, so we need a custom timeout
 565          * mechanism */
 566         timeout = 0;
 567         if (timer_pending(&sclp_request_timer)) {
 568                 /* Get timeout TOD value */
 569                 timeout = get_tod_clock_fast() +
 570                           sclp_tod_from_jiffies(sclp_request_timer.expires -
 571                                                 jiffies);
 572         }
 573         local_irq_save(flags);
 574         /* Prevent bottom half from executing once we force interrupts open */
 575         irq_context = in_interrupt();
 576         if (!irq_context)
 577                 local_bh_disable();
 578         /* Enable service-signal interruption, disable timer interrupts */
 579         old_tick = local_tick_disable();
 580         trace_hardirqs_on();
 581         __ctl_store(cr0, 0, 0);
 582         cr0_sync = cr0 & ~CR0_IRQ_SUBCLASS_MASK;
 583         cr0_sync |= 1UL << (63 - 54);
 584         __ctl_load(cr0_sync, 0, 0);
 585         __arch_local_irq_stosm(0x01);
 586         /* Loop until driver state indicates finished request */
 587         while (sclp_running_state != sclp_running_state_idle) {
 588                 /* Check for expired request timer */
 589                 if (timer_pending(&sclp_request_timer) &&
 590                     get_tod_clock_fast() > timeout &&
 591                     del_timer(&sclp_request_timer))
 592                         sclp_request_timer.function(sclp_request_timer.data);
 593                 cpu_relax();
 594         }
 595         local_irq_disable();
 596         __ctl_load(cr0, 0, 0);
 597         if (!irq_context)
 598                 _local_bh_enable();
 599         local_tick_enable(old_tick);
 600         local_irq_restore(flags);
 601 }
 602 EXPORT_SYMBOL(sclp_sync_wait);
 603
 604 /* Dispatch changes in send and receive mask to registered listeners. */
 605 static void
 606 sclp_dispatch_state_change(void)
 607 {
 608         struct list_head *l;
 609         struct sclp_register *reg;
 610         unsigned long flags;
 611         sccb_mask_t receive_mask;
 612         sccb_mask_t send_mask;
 613
 614         do {
 615                 spin_lock_irqsave(&sclp_lock, flags);
 616                 reg = NULL;
 617                 list_for_each(l, &sclp_reg_list) {
 618                         reg = list_entry(l, struct sclp_register, list);
 619                         receive_mask = reg->send_mask & sclp_receive_mask;
 620                         send_mask = reg->receive_mask & sclp_send_mask;
 621                         if (reg->sclp_receive_mask != receive_mask ||
 622                             reg->sclp_send_mask != send_mask) {
 623                                 reg->sclp_receive_mask = receive_mask;
 624                                 reg->sclp_send_mask = send_mask;
 625                                 break;
 626                         } else
 627                                 reg = NULL;
 628                 }
 629                 spin_unlock_irqrestore(&sclp_lock, flags);
 630                 if (reg && reg->state_change_fn)
 631                         reg->state_change_fn(reg);
 632         } while (reg);
 633 }
 634
 635 struct sclp_statechangebuf {
 636         struct evbuf_header     header;
 637         u8              validity_sclp_active_facility_mask : 1;
 638         u8              validity_sclp_receive_mask : 1;
 639         u8              validity_sclp_send_mask : 1;
 640         u8              validity_read_data_function_mask : 1;
 641         u16             _zeros : 12;
 642         u16             mask_length;
 643         u64             sclp_active_facility_mask;
 644         sccb_mask_t     sclp_receive_mask;
 645         sccb_mask_t     sclp_send_mask;
 646         u32             read_data_function_mask;
 647 } __attribute__((packed));
 648
 649
 650 /* State change event callback. Inform listeners of changes. */
 651 static void
 652 sclp_state_change_cb(struct evbuf_header *evbuf)
 653 {
 654         unsigned long flags;
 655         struct sclp_statechangebuf *scbuf;
 656
 657         scbuf = (struct sclp_statechangebuf *) evbuf;
 658         if (scbuf->mask_length != sizeof(sccb_mask_t))
 659                 return;
 660         spin_lock_irqsave(&sclp_lock, flags);
 661         if (scbuf->validity_sclp_receive_mask)
 662                 sclp_receive_mask = scbuf->sclp_receive_mask;
 663         if (scbuf->validity_sclp_send_mask)
 664                 sclp_send_mask = scbuf->sclp_send_mask;
 665         spin_unlock_irqrestore(&sclp_lock, flags);
 666         if (scbuf->validity_sclp_active_facility_mask)
 667                 sclp.facilities = scbuf->sclp_active_facility_mask;
 668         sclp_dispatch_state_change();
 669 }
 670
 671 static struct sclp_register sclp_state_change_event = {
 672         .receive_mask = EVTYP_STATECHANGE_MASK,
 673         .receiver_fn = sclp_state_change_cb
 674 };
 675
 676 /* Calculate receive and send mask of currently registered listeners.
 677  * Called while sclp_lock is locked. */
 678 static inline void
 679 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 680 {
 681         struct list_head *l;
 682         struct sclp_register *t;
 683
 684         *receive_mask = 0;
 685         *send_mask = 0;
 686         list_for_each(l, &sclp_reg_list) {
 687                 t = list_entry(l, struct sclp_register, list);
 688                 *receive_mask |= t->receive_mask;
 689                 *send_mask |= t->send_mask;
 690         }
 691 }
 692
 693 /* Register event listener. Return 0 on success, non-zero otherwise. */
 694 int
 695 sclp_register(struct sclp_register *reg)
 696 {
 697         unsigned long flags;
 698         sccb_mask_t receive_mask;
 699         sccb_mask_t send_mask;
 700         int rc;
 701
 702         rc = sclp_init();
 703         if (rc)
 704                 return rc;
 705         spin_lock_irqsave(&sclp_lock, flags);
 706         /* Check event mask for collisions */
 707         __sclp_get_mask(&receive_mask, &send_mask);
 708         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 709                 spin_unlock_irqrestore(&sclp_lock, flags);
 710                 return -EBUSY;
 711         }
 712         /* Trigger initial state change callback */
 713         reg->sclp_receive_mask = 0;
 714         reg->sclp_send_mask = 0;
 715         reg->pm_event_posted = 0;
 716         list_add(&reg->list, &sclp_reg_list);
 717         spin_unlock_irqrestore(&sclp_lock, flags);
 718         rc = sclp_init_mask(1);
 719         if (rc) {
 720                 spin_lock_irqsave(&sclp_lock, flags);
 721                 list_del(&reg->list);
 722                 spin_unlock_irqrestore(&sclp_lock, flags);
 723         }
 724         return rc;
 725 }
 726
 727 EXPORT_SYMBOL(sclp_register);
 728
 729 /* Unregister event listener. */
 730 void
 731 sclp_unregister(struct sclp_register *reg)
 732 {
 733         unsigned long flags;
 734
 735         spin_lock_irqsave(&sclp_lock, flags);
 736         list_del(&reg->list);
 737         spin_unlock_irqrestore(&sclp_lock, flags);
 738         sclp_init_mask(1);
 739 }
 740
 741 EXPORT_SYMBOL(sclp_unregister);
 742
 743 /* Remove event buffers which are marked processed. Return the number of
 744  * remaining event buffers. */
 745 int
 746 sclp_remove_processed(struct sccb_header *sccb)
 747 {
 748         struct evbuf_header *evbuf;
 749         int unprocessed;
 750         u16 remaining;
 751
 752         evbuf = (struct evbuf_header *) (sccb + 1);
 753         unprocessed = 0;
 754         remaining = sccb->length - sizeof(struct sccb_header);
 755         while (remaining > 0) {
 756                 remaining -= evbuf->length;
 757                 if (evbuf->flags & 0x80) {
 758                         sccb->length -= evbuf->length;
 759                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 760                                remaining);
 761                 } else {
 762                         unprocessed++;
 763                         evbuf = (struct evbuf_header *)
 764                                         ((addr_t) evbuf + evbuf->length);
 765                 }
 766         }
 767         return unprocessed;
 768 }
 769
 770 EXPORT_SYMBOL(sclp_remove_processed);
 771
 772 /* Prepare init mask request. Called while sclp_lock is locked. */
 773 static inline void
 774 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 775 {
 776         struct init_sccb *sccb;
 777
 778         sccb = (struct init_sccb *) sclp_init_sccb;
 779         clear_page(sccb);
 780         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 781         sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 782         sclp_init_req.status = SCLP_REQ_FILLED;
 783         sclp_init_req.start_count = 0;
 784         sclp_init_req.callback = NULL;
 785         sclp_init_req.callback_data = NULL;
 786         sclp_init_req.sccb = sccb;
 787         sccb->header.length = sizeof(struct init_sccb);
 788         sccb->mask_length = sizeof(sccb_mask_t);
 789         sccb->receive_mask = receive_mask;
 790         sccb->send_mask = send_mask;
 791         sccb->sclp_receive_mask = 0;
 792         sccb->sclp_send_mask = 0;
 793 }
 794
 795 /* Start init mask request. If calculate is non-zero, calculate the mask as
 796  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 797  * success, non-zero otherwise. */
 798 static int
 799 sclp_init_mask(int calculate)
 800 {
 801         unsigned long flags;
 802         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 803         sccb_mask_t receive_mask;
 804         sccb_mask_t send_mask;
 805         int retry;
 806         int rc;
 807         unsigned long wait;
 808
 809         spin_lock_irqsave(&sclp_lock, flags);
 810         /* Check if interface is in appropriate state */
 811         if (sclp_mask_state != sclp_mask_state_idle) {
 812                 spin_unlock_irqrestore(&sclp_lock, flags);
 813                 return -EBUSY;
 814         }
 815         if (sclp_activation_state == sclp_activation_state_inactive) {
 816                 spin_unlock_irqrestore(&sclp_lock, flags);
 817                 return -EINVAL;
 818         }
 819         sclp_mask_state = sclp_mask_state_initializing;
 820         /* Determine mask */
 821         if (calculate)
 822                 __sclp_get_mask(&receive_mask, &send_mask);
 823         else {
 824                 receive_mask = 0;
 825                 send_mask = 0;
 826         }
 827         rc = -EIO;
 828         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 829                 /* Prepare request */
 830                 __sclp_make_init_req(receive_mask, send_mask);
 831                 spin_unlock_irqrestore(&sclp_lock, flags);
 832                 if (sclp_add_request(&sclp_init_req)) {
 833                         /* Try again later */
 834                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 835                         while (time_before(jiffies, wait))
 836                                 sclp_sync_wait();
 837                         spin_lock_irqsave(&sclp_lock, flags);
 838                         continue;
 839                 }
 840                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 841                        sclp_init_req.status != SCLP_REQ_FAILED)
 842                         sclp_sync_wait();
 843                 spin_lock_irqsave(&sclp_lock, flags);
 844                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 845                     sccb->header.response_code == 0x20) {
 846                         /* Successful request */
 847                         if (calculate) {
 848                                 sclp_receive_mask = sccb->sclp_receive_mask;
 849                                 sclp_send_mask = sccb->sclp_send_mask;
 850                         } else {
 851                                 sclp_receive_mask = 0;
 852                                 sclp_send_mask = 0;
 853                         }
 854                         spin_unlock_irqrestore(&sclp_lock, flags);
 855                         sclp_dispatch_state_change();
 856                         spin_lock_irqsave(&sclp_lock, flags);
 857                         rc = 0;
 858                         break;
 859                 }
 860         }
 861         sclp_mask_state = sclp_mask_state_idle;
 862         spin_unlock_irqrestore(&sclp_lock, flags);
 863         return rc;
 864 }
 865
 866 /* Deactivate SCLP interface. On success, new requests will be rejected,
 867  * events will no longer be dispatched. Return 0 on success, non-zero
 868  * otherwise. */
 869 int
 870 sclp_deactivate(void)
 871 {
 872         unsigned long flags;
 873         int rc;
 874
 875         spin_lock_irqsave(&sclp_lock, flags);
 876         /* Deactivate can only be called when active */
 877         if (sclp_activation_state != sclp_activation_state_active) {
 878                 spin_unlock_irqrestore(&sclp_lock, flags);
 879                 return -EINVAL;
 880         }
 881         sclp_activation_state = sclp_activation_state_deactivating;
 882         spin_unlock_irqrestore(&sclp_lock, flags);
 883         rc = sclp_init_mask(0);
 884         spin_lock_irqsave(&sclp_lock, flags);
 885         if (rc == 0)
 886                 sclp_activation_state = sclp_activation_state_inactive;
 887         else
 888                 sclp_activation_state = sclp_activation_state_active;
 889         spin_unlock_irqrestore(&sclp_lock, flags);
 890         return rc;
 891 }
 892
 893 EXPORT_SYMBOL(sclp_deactivate);
 894
 895 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 896  * requests will be accepted, events will be dispatched again. Return 0 on
 897  * success, non-zero otherwise. */
 898 int
 899 sclp_reactivate(void)
 900 {
 901         unsigned long flags;
 902         int rc;
 903
 904         spin_lock_irqsave(&sclp_lock, flags);
 905         /* Reactivate can only be called when inactive */
 906         if (sclp_activation_state != sclp_activation_state_inactive) {
 907                 spin_unlock_irqrestore(&sclp_lock, flags);
 908                 return -EINVAL;
 909         }
 910         sclp_activation_state = sclp_activation_state_activating;
 911         spin_unlock_irqrestore(&sclp_lock, flags);
 912         rc = sclp_init_mask(1);
 913         spin_lock_irqsave(&sclp_lock, flags);
 914         if (rc == 0)
 915                 sclp_activation_state = sclp_activation_state_active;
 916         else
 917                 sclp_activation_state = sclp_activation_state_inactive;
 918         spin_unlock_irqrestore(&sclp_lock, flags);
 919         return rc;
 920 }
 921
 922 EXPORT_SYMBOL(sclp_reactivate);
 923
 924 /* Handler for external interruption used during initialization. Modify
 925  * request state to done. */
 926 static void sclp_check_handler(struct ext_code ext_code,
 927                                unsigned int param32, unsigned long param64)
 928 {
 929         u32 finished_sccb;
 930
 931         inc_irq_stat(IRQEXT_SCP);
 932         finished_sccb = param32 & 0xfffffff8;
 933         /* Is this the interrupt we are waiting for? */
 934         if (finished_sccb == 0)
 935                 return;
 936         if (finished_sccb != (u32) (addr_t) sclp_init_sccb)
 937                 panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
 938                       finished_sccb);
 939         spin_lock(&sclp_lock);
 940         if (sclp_running_state == sclp_running_state_running) {
 941                 sclp_init_req.status = SCLP_REQ_DONE;
 942                 sclp_running_state = sclp_running_state_idle;
 943         }
 944         spin_unlock(&sclp_lock);
 945 }
 946
 947 /* Initial init mask request timed out. Modify request state to failed. */
 948 static void
 949 sclp_check_timeout(unsigned long data)
 950 {
 951         unsigned long flags;
 952
 953         spin_lock_irqsave(&sclp_lock, flags);
 954         if (sclp_running_state == sclp_running_state_running) {
 955                 sclp_init_req.status = SCLP_REQ_FAILED;
 956                 sclp_running_state = sclp_running_state_idle;
 957         }
 958         spin_unlock_irqrestore(&sclp_lock, flags);
 959 }
 960
 961 /* Perform a check of the SCLP interface. Return zero if the interface is
 962  * available and there are no pending requests from a previous instance.
 963  * Return non-zero otherwise. */
 964 static int
 965 sclp_check_interface(void)
 966 {
 967         struct init_sccb *sccb;
 968         unsigned long flags;
 969         int retry;
 970         int rc;
 971
 972         spin_lock_irqsave(&sclp_lock, flags);
 973         /* Prepare init mask command */
 974         rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
 975         if (rc) {
 976                 spin_unlock_irqrestore(&sclp_lock, flags);
 977                 return rc;
 978         }
 979         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 980                 __sclp_make_init_req(0, 0);
 981                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 982                 rc = sclp_service_call(sclp_init_req.command, sccb);
 983                 if (rc == -EIO)
 984                         break;
 985                 sclp_init_req.status = SCLP_REQ_RUNNING;
 986                 sclp_running_state = sclp_running_state_running;
 987                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 988                                          sclp_check_timeout, 0);
 989                 spin_unlock_irqrestore(&sclp_lock, flags);
 990                 /* Enable service-signal interruption - needs to happen
 991                  * with IRQs enabled. */
 992                 irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
 993                 /* Wait for signal from interrupt or timeout */
 994                 sclp_sync_wait();
 995                 /* Disable service-signal interruption - needs to happen
 996                  * with IRQs enabled. */
 997                 irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
 998                 spin_lock_irqsave(&sclp_lock, flags);
 999                 del_timer(&sclp_request_timer);
1000                 if (sclp_init_req.status == SCLP_REQ_DONE &&
1001                     sccb->header.response_code == 0x20) {
1002                         rc = 0;
1003                         break;
1004                 } else
1005                         rc = -EBUSY;
1006         }
1007         unregister_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
1008         spin_unlock_irqrestore(&sclp_lock, flags);
1009         return rc;
1010 }
1011
1012 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
1013  * events from interfering with rebooted system. */
1014 static int
1015 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
1016 {
1017         sclp_deactivate();
1018         return NOTIFY_DONE;
1019 }
1020
1021 static struct notifier_block sclp_reboot_notifier = {
1022         .notifier_call = sclp_reboot_event
1023 };
1024
1025 /*
1026  * Suspend/resume SCLP notifier implementation
1027  */
1028
1029 static void sclp_pm_event(enum sclp_pm_event sclp_pm_event, int rollback)
1030 {
1031         struct sclp_register *reg;
1032         unsigned long flags;
1033
1034         if (!rollback) {
1035                 spin_lock_irqsave(&sclp_lock, flags);
1036                 list_for_each_entry(reg, &sclp_reg_list, list)
1037                         reg->pm_event_posted = 0;
1038                 spin_unlock_irqrestore(&sclp_lock, flags);
1039         }
1040         do {
1041                 spin_lock_irqsave(&sclp_lock, flags);
1042                 list_for_each_entry(reg, &sclp_reg_list, list) {
1043                         if (rollback && reg->pm_event_posted)
1044                                 goto found;
1045                         if (!rollback && !reg->pm_event_posted)
1046                                 goto found;
1047                 }
1048                 spin_unlock_irqrestore(&sclp_lock, flags);
1049                 return;
1050 found:
1051                 spin_unlock_irqrestore(&sclp_lock, flags);
1052                 if (reg->pm_event_fn)
1053                         reg->pm_event_fn(reg, sclp_pm_event);
1054                 reg->pm_event_posted = rollback ? 0 : 1;
1055         } while (1);
1056 }
1057
1058 /*
1059  * Susend/resume callbacks for platform device
1060  */
1061
1062 static int sclp_freeze(struct device *dev)
1063 {
1064         unsigned long flags;
1065         int rc;
1066
1067         sclp_pm_event(SCLP_PM_EVENT_FREEZE, 0);
1068
1069         spin_lock_irqsave(&sclp_lock, flags);
1070         sclp_suspend_state = sclp_suspend_state_suspended;
1071         spin_unlock_irqrestore(&sclp_lock, flags);
1072
1073         /* Init supend data */
1074         memset(&sclp_suspend_req, 0, sizeof(sclp_suspend_req));
1075         sclp_suspend_req.callback = sclp_suspend_req_cb;
1076         sclp_suspend_req.status = SCLP_REQ_FILLED;
1077         init_completion(&sclp_request_queue_flushed);
1078
1079         rc = sclp_add_request(&sclp_suspend_req);
1080         if (rc == 0)
1081                 wait_for_completion(&sclp_request_queue_flushed);
1082         else if (rc != -ENODATA)
1083                 goto fail_thaw;
1084
1085         rc = sclp_deactivate();
1086         if (rc)
1087                 goto fail_thaw;
1088         return 0;
1089
1090 fail_thaw:
1091         spin_lock_irqsave(&sclp_lock, flags);
1092         sclp_suspend_state = sclp_suspend_state_running;
1093         spin_unlock_irqrestore(&sclp_lock, flags);
1094         sclp_pm_event(SCLP_PM_EVENT_THAW, 1);
1095         return rc;
1096 }
1097
1098 static int sclp_undo_suspend(enum sclp_pm_event event)
1099 {
1100         unsigned long flags;
1101         int rc;
1102
1103         rc = sclp_reactivate();
1104         if (rc)
1105                 return rc;
1106
1107         spin_lock_irqsave(&sclp_lock, flags);
1108         sclp_suspend_state = sclp_suspend_state_running;
1109         spin_unlock_irqrestore(&sclp_lock, flags);
1110
1111         sclp_pm_event(event, 0);
1112         return 0;
1113 }
1114
1115 static int sclp_thaw(struct device *dev)
1116 {
1117         return sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1118 }
1119
1120 static int sclp_restore(struct device *dev)
1121 {
1122         return sclp_undo_suspend(SCLP_PM_EVENT_RESTORE);
1123 }
1124
1125 static const struct dev_pm_ops sclp_pm_ops = {
1126         .freeze         = sclp_freeze,
1127         .thaw           = sclp_thaw,
1128         .restore        = sclp_restore,
1129 };
1130
1131 static ssize_t sclp_show_console_pages(struct device_driver *dev, char *buf)
1132 {
1133         return sprintf(buf, "%i\n", sclp_console_pages);
1134 }
1135
1136 static DRIVER_ATTR(con_pages, S_IRUSR, sclp_show_console_pages, NULL);
1137
1138 static ssize_t sclp_show_con_drop(struct device_driver *dev, char *buf)
1139 {
1140         return sprintf(buf, "%i\n", sclp_console_drop);
1141 }
1142
1143 static DRIVER_ATTR(con_drop, S_IRUSR, sclp_show_con_drop, NULL);
1144
1145 static ssize_t sclp_show_console_full(struct device_driver *dev, char *buf)
1146 {
1147         return sprintf(buf, "%lu\n", sclp_console_full);
1148 }
1149
1150 static DRIVER_ATTR(con_full, S_IRUSR, sclp_show_console_full, NULL);
1151
1152 static struct attribute *sclp_drv_attrs[] = {
1153         &driver_attr_con_pages.attr,
1154         &driver_attr_con_drop.attr,
1155         &driver_attr_con_full.attr,
1156         NULL,
1157 };
1158 static struct attribute_group sclp_drv_attr_group = {
1159         .attrs = sclp_drv_attrs,
1160 };
1161 static const struct attribute_group *sclp_drv_attr_groups[] = {
1162         &sclp_drv_attr_group,
1163         NULL,
1164 };
1165
1166 static struct platform_driver sclp_pdrv = {
1167         .driver = {
1168                 .name   = "sclp",
1169                 .pm     = &sclp_pm_ops,
1170                 .groups = sclp_drv_attr_groups,
1171         },
1172 };
1173
1174 static struct platform_device *sclp_pdev;
1175
1176 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
1177  * otherwise. */
1178 static int
1179 sclp_init(void)
1180 {
1181         unsigned long flags;
1182         int rc = 0;
1183
1184         spin_lock_irqsave(&sclp_lock, flags);
1185         /* Check for previous or running initialization */
1186         if (sclp_init_state != sclp_init_state_uninitialized)
1187                 goto fail_unlock;
1188         sclp_init_state = sclp_init_state_initializing;
1189         /* Set up variables */
1190         INIT_LIST_HEAD(&sclp_req_queue);
1191         INIT_LIST_HEAD(&sclp_reg_list);
1192         list_add(&sclp_state_change_event.list, &sclp_reg_list);
1193         init_timer(&sclp_request_timer);
1194         init_timer(&sclp_queue_timer);
1195         sclp_queue_timer.function = sclp_req_queue_timeout;
1196         /* Check interface */
1197         spin_unlock_irqrestore(&sclp_lock, flags);
1198         rc = sclp_check_interface();
1199         spin_lock_irqsave(&sclp_lock, flags);
1200         if (rc)
1201                 goto fail_init_state_uninitialized;
1202         /* Register reboot handler */
1203         rc = register_reboot_notifier(&sclp_reboot_notifier);
1204         if (rc)
1205                 goto fail_init_state_uninitialized;
1206         /* Register interrupt handler */
1207         rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_interrupt_handler);
1208         if (rc)
1209                 goto fail_unregister_reboot_notifier;
1210         sclp_init_state = sclp_init_state_initialized;
1211         spin_unlock_irqrestore(&sclp_lock, flags);
1212         /* Enable service-signal external interruption - needs to happen with
1213          * IRQs enabled. */
1214         irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1215         sclp_init_mask(1);
1216         return 0;
1217
1218 fail_unregister_reboot_notifier:
1219         unregister_reboot_notifier(&sclp_reboot_notifier);
1220 fail_init_state_uninitialized:
1221         sclp_init_state = sclp_init_state_uninitialized;
1222 fail_unlock:
1223         spin_unlock_irqrestore(&sclp_lock, flags);
1224         return rc;
1225 }
1226
1227 /*
1228  * SCLP panic notifier: If we are suspended, we thaw SCLP in order to be able
1229  * to print the panic message.
1230  */
1231 static int sclp_panic_notify(struct notifier_block *self,
1232                              unsigned long event, void *data)
1233 {
1234         if (sclp_suspend_state == sclp_suspend_state_suspended)
1235                 sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1236         return NOTIFY_OK;
1237 }
1238
1239 static struct notifier_block sclp_on_panic_nb = {
1240         .notifier_call = sclp_panic_notify,
1241         .priority = SCLP_PANIC_PRIO,
1242 };
1243
1244 static __init int sclp_initcall(void)
1245 {
1246         int rc;
1247
1248         rc = platform_driver_register(&sclp_pdrv);
1249         if (rc)
1250                 return rc;
1251
1252         sclp_pdev = platform_device_register_simple("sclp", -1, NULL, 0);
1253         rc = PTR_ERR_OR_ZERO(sclp_pdev);
1254         if (rc)
1255                 goto fail_platform_driver_unregister;
1256
1257         rc = atomic_notifier_chain_register(&panic_notifier_list,
1258                                             &sclp_on_panic_nb);
1259         if (rc)
1260                 goto fail_platform_device_unregister;
1261
1262         return sclp_init();
1263
1264 fail_platform_device_unregister:
1265         platform_device_unregister(sclp_pdev);
1266 fail_platform_driver_unregister:
1267         platform_driver_unregister(&sclp_pdrv);
1268         return rc;
1269 }
1270
1271 arch_initcall(sclp_initcall);