Pileus Git - ~andy/linux/blob - 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/s390_ext.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 static void sclp_suspend_req_cb(struct sclp_req *req, void *data)
  55 {
  56         complete(&sclp_request_queue_flushed);
  57 }
  58
  59 static struct sclp_req sclp_suspend_req;
  60
  61 /* Timer for request retries. */
  62 static struct timer_list sclp_request_timer;
  63
  64 /* Internal state: is the driver initialized? */
  65 static volatile enum sclp_init_state_t {
  66         sclp_init_state_uninitialized,
  67         sclp_init_state_initializing,
  68         sclp_init_state_initialized
  69 } sclp_init_state = sclp_init_state_uninitialized;
  70
  71 /* Internal state: is a request active at the sclp? */
  72 static volatile enum sclp_running_state_t {
  73         sclp_running_state_idle,
  74         sclp_running_state_running,
  75         sclp_running_state_reset_pending
  76 } sclp_running_state = sclp_running_state_idle;
  77
  78 /* Internal state: is a read request pending? */
  79 static volatile enum sclp_reading_state_t {
  80         sclp_reading_state_idle,
  81         sclp_reading_state_reading
  82 } sclp_reading_state = sclp_reading_state_idle;
  83
  84 /* Internal state: is the driver currently serving requests? */
  85 static volatile enum sclp_activation_state_t {
  86         sclp_activation_state_active,
  87         sclp_activation_state_deactivating,
  88         sclp_activation_state_inactive,
  89         sclp_activation_state_activating
  90 } sclp_activation_state = sclp_activation_state_active;
  91
  92 /* Internal state: is an init mask request pending? */
  93 static volatile enum sclp_mask_state_t {
  94         sclp_mask_state_idle,
  95         sclp_mask_state_initializing
  96 } sclp_mask_state = sclp_mask_state_idle;
  97
  98 /* Internal state: is the driver suspended? */
  99 static enum sclp_suspend_state_t {
 100         sclp_suspend_state_running,
 101         sclp_suspend_state_suspended,
 102 } sclp_suspend_state = sclp_suspend_state_running;
 103
 104 /* Maximum retry counts */
 105 #define SCLP_INIT_RETRY         3
 106 #define SCLP_MASK_RETRY         3
 107
 108 /* Timeout intervals in seconds.*/
 109 #define SCLP_BUSY_INTERVAL      10
 110 #define SCLP_RETRY_INTERVAL     30
 111
 112 static void sclp_process_queue(void);
 113 static void __sclp_make_read_req(void);
 114 static int sclp_init_mask(int calculate);
 115 static int sclp_init(void);
 116
 117 /* Perform service call. Return 0 on success, non-zero otherwise. */
 118 int
 119 sclp_service_call(sclp_cmdw_t command, void *sccb)
 120 {
 121         int cc;
 122
 123         asm volatile(
 124                 "       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
 125                 "       ipm     %0\n"
 126                 "       srl     %0,28"
 127                 : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
 128                 : "cc", "memory");
 129         if (cc == 3)
 130                 return -EIO;
 131         if (cc == 2)
 132                 return -EBUSY;
 133         return 0;
 134 }
 135
 136
 137 static void
 138 __sclp_queue_read_req(void)
 139 {
 140         if (sclp_reading_state == sclp_reading_state_idle) {
 141                 sclp_reading_state = sclp_reading_state_reading;
 142                 __sclp_make_read_req();
 143                 /* Add request to head of queue */
 144                 list_add(&sclp_read_req.list, &sclp_req_queue);
 145         }
 146 }
 147
 148 /* Set up request retry timer. Called while sclp_lock is locked. */
 149 static inline void
 150 __sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
 151                          unsigned long data)
 152 {
 153         del_timer(&sclp_request_timer);
 154         sclp_request_timer.function = function;
 155         sclp_request_timer.data = data;
 156         sclp_request_timer.expires = jiffies + time;
 157         add_timer(&sclp_request_timer);
 158 }
 159
 160 /* Request timeout handler. Restart the request queue. If DATA is non-zero,
 161  * force restart of running request. */
 162 static void
 163 sclp_request_timeout(unsigned long data)
 164 {
 165         unsigned long flags;
 166
 167         spin_lock_irqsave(&sclp_lock, flags);
 168         if (data) {
 169                 if (sclp_running_state == sclp_running_state_running) {
 170                         /* Break running state and queue NOP read event request
 171                          * to get a defined interface state. */
 172                         __sclp_queue_read_req();
 173                         sclp_running_state = sclp_running_state_idle;
 174                 }
 175         } else {
 176                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 177                                          sclp_request_timeout, 0);
 178         }
 179         spin_unlock_irqrestore(&sclp_lock, flags);
 180         sclp_process_queue();
 181 }
 182
 183 /* Try to start a request. Return zero if the request was successfully
 184  * started or if it will be started at a later time. Return non-zero otherwise.
 185  * Called while sclp_lock is locked. */
 186 static int
 187 __sclp_start_request(struct sclp_req *req)
 188 {
 189         int rc;
 190
 191         if (sclp_running_state != sclp_running_state_idle)
 192                 return 0;
 193         del_timer(&sclp_request_timer);
 194         rc = sclp_service_call(req->command, req->sccb);
 195         req->start_count++;
 196
 197         if (rc == 0) {
 198                 /* Successfully started request */
 199                 req->status = SCLP_REQ_RUNNING;
 200                 sclp_running_state = sclp_running_state_running;
 201                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 202                                          sclp_request_timeout, 1);
 203                 return 0;
 204         } else if (rc == -EBUSY) {
 205                 /* Try again later */
 206                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 207                                          sclp_request_timeout, 0);
 208                 return 0;
 209         }
 210         /* Request failed */
 211         req->status = SCLP_REQ_FAILED;
 212         return rc;
 213 }
 214
 215 /* Try to start queued requests. */
 216 static void
 217 sclp_process_queue(void)
 218 {
 219         struct sclp_req *req;
 220         int rc;
 221         unsigned long flags;
 222
 223         spin_lock_irqsave(&sclp_lock, flags);
 224         if (sclp_running_state != sclp_running_state_idle) {
 225                 spin_unlock_irqrestore(&sclp_lock, flags);
 226                 return;
 227         }
 228         del_timer(&sclp_request_timer);
 229         while (!list_empty(&sclp_req_queue)) {
 230                 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
 231                 if (!req->sccb)
 232                         goto do_post;
 233                 rc = __sclp_start_request(req);
 234                 if (rc == 0)
 235                         break;
 236                 /* Request failed */
 237                 if (req->start_count > 1) {
 238                         /* Cannot abort already submitted request - could still
 239                          * be active at the SCLP */
 240                         __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 241                                                  sclp_request_timeout, 0);
 242                         break;
 243                 }
 244 do_post:
 245                 /* Post-processing for aborted request */
 246                 list_del(&req->list);
 247                 if (req->callback) {
 248                         spin_unlock_irqrestore(&sclp_lock, flags);
 249                         req->callback(req, req->callback_data);
 250                         spin_lock_irqsave(&sclp_lock, flags);
 251                 }
 252         }
 253         spin_unlock_irqrestore(&sclp_lock, flags);
 254 }
 255
 256 static int __sclp_can_add_request(struct sclp_req *req)
 257 {
 258         if (req == &sclp_suspend_req || req == &sclp_init_req)
 259                 return 1;
 260         if (sclp_suspend_state != sclp_suspend_state_running)
 261                 return 0;
 262         if (sclp_init_state != sclp_init_state_initialized)
 263                 return 0;
 264         if (sclp_activation_state != sclp_activation_state_active)
 265                 return 0;
 266         return 1;
 267 }
 268
 269 /* Queue a new request. Return zero on success, non-zero otherwise. */
 270 int
 271 sclp_add_request(struct sclp_req *req)
 272 {
 273         unsigned long flags;
 274         int rc;
 275
 276         spin_lock_irqsave(&sclp_lock, flags);
 277         if (!__sclp_can_add_request(req)) {
 278                 spin_unlock_irqrestore(&sclp_lock, flags);
 279                 return -EIO;
 280         }
 281         req->status = SCLP_REQ_QUEUED;
 282         req->start_count = 0;
 283         list_add_tail(&req->list, &sclp_req_queue);
 284         rc = 0;
 285         /* Start if request is first in list */
 286         if (sclp_running_state == sclp_running_state_idle &&
 287             req->list.prev == &sclp_req_queue) {
 288                 if (!req->sccb) {
 289                         list_del(&req->list);
 290                         rc = -ENODATA;
 291                         goto out;
 292                 }
 293                 rc = __sclp_start_request(req);
 294                 if (rc)
 295                         list_del(&req->list);
 296         }
 297 out:
 298         spin_unlock_irqrestore(&sclp_lock, flags);
 299         return rc;
 300 }
 301
 302 EXPORT_SYMBOL(sclp_add_request);
 303
 304 /* Dispatch events found in request buffer to registered listeners. Return 0
 305  * if all events were dispatched, non-zero otherwise. */
 306 static int
 307 sclp_dispatch_evbufs(struct sccb_header *sccb)
 308 {
 309         unsigned long flags;
 310         struct evbuf_header *evbuf;
 311         struct list_head *l;
 312         struct sclp_register *reg;
 313         int offset;
 314         int rc;
 315
 316         spin_lock_irqsave(&sclp_lock, flags);
 317         rc = 0;
 318         for (offset = sizeof(struct sccb_header); offset < sccb->length;
 319              offset += evbuf->length) {
 320                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 321                 /* Check for malformed hardware response */
 322                 if (evbuf->length == 0)
 323                         break;
 324                 /* Search for event handler */
 325                 reg = NULL;
 326                 list_for_each(l, &sclp_reg_list) {
 327                         reg = list_entry(l, struct sclp_register, list);
 328                         if (reg->receive_mask & (1 << (32 - evbuf->type)))
 329                                 break;
 330                         else
 331                                 reg = NULL;
 332                 }
 333                 if (reg && reg->receiver_fn) {
 334                         spin_unlock_irqrestore(&sclp_lock, flags);
 335                         reg->receiver_fn(evbuf);
 336                         spin_lock_irqsave(&sclp_lock, flags);
 337                 } else if (reg == NULL)
 338                         rc = -ENOSYS;
 339         }
 340         spin_unlock_irqrestore(&sclp_lock, flags);
 341         return rc;
 342 }
 343
 344 /* Read event data request callback. */
 345 static void
 346 sclp_read_cb(struct sclp_req *req, void *data)
 347 {
 348         unsigned long flags;
 349         struct sccb_header *sccb;
 350
 351         sccb = (struct sccb_header *) req->sccb;
 352         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 353             sccb->response_code == 0x220))
 354                 sclp_dispatch_evbufs(sccb);
 355         spin_lock_irqsave(&sclp_lock, flags);
 356         sclp_reading_state = sclp_reading_state_idle;
 357         spin_unlock_irqrestore(&sclp_lock, flags);
 358 }
 359
 360 /* Prepare read event data request. Called while sclp_lock is locked. */
 361 static void __sclp_make_read_req(void)
 362 {
 363         struct sccb_header *sccb;
 364
 365         sccb = (struct sccb_header *) sclp_read_sccb;
 366         clear_page(sccb);
 367         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 368         sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
 369         sclp_read_req.status = SCLP_REQ_QUEUED;
 370         sclp_read_req.start_count = 0;
 371         sclp_read_req.callback = sclp_read_cb;
 372         sclp_read_req.sccb = sccb;
 373         sccb->length = PAGE_SIZE;
 374         sccb->function_code = 0;
 375         sccb->control_mask[2] = 0x80;
 376 }
 377
 378 /* Search request list for request with matching sccb. Return request if found,
 379  * NULL otherwise. Called while sclp_lock is locked. */
 380 static inline struct sclp_req *
 381 __sclp_find_req(u32 sccb)
 382 {
 383         struct list_head *l;
 384         struct sclp_req *req;
 385
 386         list_for_each(l, &sclp_req_queue) {
 387                 req = list_entry(l, struct sclp_req, list);
 388                 if (sccb == (u32) (addr_t) req->sccb)
 389                                 return req;
 390         }
 391         return NULL;
 392 }
 393
 394 /* Handler for external interruption. Perform request post-processing.
 395  * Prepare read event data request if necessary. Start processing of next
 396  * request on queue. */
 397 static void sclp_interrupt_handler(unsigned int ext_int_code,
 398                                    unsigned int param32, unsigned long param64)
 399 {
 400         struct sclp_req *req;
 401         u32 finished_sccb;
 402         u32 evbuf_pending;
 403
 404         kstat_cpu(smp_processor_id()).irqs[EXTINT_SCP]++;
 405         spin_lock(&sclp_lock);
 406         finished_sccb = param32 & 0xfffffff8;
 407         evbuf_pending = param32 & 0x3;
 408         if (finished_sccb) {
 409                 del_timer(&sclp_request_timer);
 410                 sclp_running_state = sclp_running_state_reset_pending;
 411                 req = __sclp_find_req(finished_sccb);
 412                 if (req) {
 413                         /* Request post-processing */
 414                         list_del(&req->list);
 415                         req->status = SCLP_REQ_DONE;
 416                         if (req->callback) {
 417                                 spin_unlock(&sclp_lock);
 418                                 req->callback(req, req->callback_data);
 419                                 spin_lock(&sclp_lock);
 420                         }
 421                 }
 422                 sclp_running_state = sclp_running_state_idle;
 423         }
 424         if (evbuf_pending &&
 425             sclp_activation_state == sclp_activation_state_active)
 426                 __sclp_queue_read_req();
 427         spin_unlock(&sclp_lock);
 428         sclp_process_queue();
 429 }
 430
 431 /* Convert interval in jiffies to TOD ticks. */
 432 static inline u64
 433 sclp_tod_from_jiffies(unsigned long jiffies)
 434 {
 435         return (u64) (jiffies / HZ) << 32;
 436 }
 437
 438 /* Wait until a currently running request finished. Note: while this function
 439  * is running, no timers are served on the calling CPU. */
 440 void
 441 sclp_sync_wait(void)
 442 {
 443         unsigned long long old_tick;
 444         unsigned long flags;
 445         unsigned long cr0, cr0_sync;
 446         u64 timeout;
 447         int irq_context;
 448
 449         /* We'll be disabling timer interrupts, so we need a custom timeout
 450          * mechanism */
 451         timeout = 0;
 452         if (timer_pending(&sclp_request_timer)) {
 453                 /* Get timeout TOD value */
 454                 timeout = get_clock() +
 455                           sclp_tod_from_jiffies(sclp_request_timer.expires -
 456                                                 jiffies);
 457         }
 458         local_irq_save(flags);
 459         /* Prevent bottom half from executing once we force interrupts open */
 460         irq_context = in_interrupt();
 461         if (!irq_context)
 462                 local_bh_disable();
 463         /* Enable service-signal interruption, disable timer interrupts */
 464         old_tick = local_tick_disable();
 465         trace_hardirqs_on();
 466         __ctl_store(cr0, 0, 0);
 467         cr0_sync = cr0;
 468         cr0_sync &= 0xffff00a0;
 469         cr0_sync |= 0x00000200;
 470         __ctl_load(cr0_sync, 0, 0);
 471         __arch_local_irq_stosm(0x01);
 472         /* Loop until driver state indicates finished request */
 473         while (sclp_running_state != sclp_running_state_idle) {
 474                 /* Check for expired request timer */
 475                 if (timer_pending(&sclp_request_timer) &&
 476                     get_clock() > timeout &&
 477                     del_timer(&sclp_request_timer))
 478                         sclp_request_timer.function(sclp_request_timer.data);
 479                 cpu_relax();
 480         }
 481         local_irq_disable();
 482         __ctl_load(cr0, 0, 0);
 483         if (!irq_context)
 484                 _local_bh_enable();
 485         local_tick_enable(old_tick);
 486         local_irq_restore(flags);
 487 }
 488 EXPORT_SYMBOL(sclp_sync_wait);
 489
 490 /* Dispatch changes in send and receive mask to registered listeners. */
 491 static void
 492 sclp_dispatch_state_change(void)
 493 {
 494         struct list_head *l;
 495         struct sclp_register *reg;
 496         unsigned long flags;
 497         sccb_mask_t receive_mask;
 498         sccb_mask_t send_mask;
 499
 500         do {
 501                 spin_lock_irqsave(&sclp_lock, flags);
 502                 reg = NULL;
 503                 list_for_each(l, &sclp_reg_list) {
 504                         reg = list_entry(l, struct sclp_register, list);
 505                         receive_mask = reg->send_mask & sclp_receive_mask;
 506                         send_mask = reg->receive_mask & sclp_send_mask;
 507                         if (reg->sclp_receive_mask != receive_mask ||
 508                             reg->sclp_send_mask != send_mask) {
 509                                 reg->sclp_receive_mask = receive_mask;
 510                                 reg->sclp_send_mask = send_mask;
 511                                 break;
 512                         } else
 513                                 reg = NULL;
 514                 }
 515                 spin_unlock_irqrestore(&sclp_lock, flags);
 516                 if (reg && reg->state_change_fn)
 517                         reg->state_change_fn(reg);
 518         } while (reg);
 519 }
 520
 521 struct sclp_statechangebuf {
 522         struct evbuf_header     header;
 523         u8              validity_sclp_active_facility_mask : 1;
 524         u8              validity_sclp_receive_mask : 1;
 525         u8              validity_sclp_send_mask : 1;
 526         u8              validity_read_data_function_mask : 1;
 527         u16             _zeros : 12;
 528         u16             mask_length;
 529         u64             sclp_active_facility_mask;
 530         sccb_mask_t     sclp_receive_mask;
 531         sccb_mask_t     sclp_send_mask;
 532         u32             read_data_function_mask;
 533 } __attribute__((packed));
 534
 535
 536 /* State change event callback. Inform listeners of changes. */
 537 static void
 538 sclp_state_change_cb(struct evbuf_header *evbuf)
 539 {
 540         unsigned long flags;
 541         struct sclp_statechangebuf *scbuf;
 542
 543         scbuf = (struct sclp_statechangebuf *) evbuf;
 544         if (scbuf->mask_length != sizeof(sccb_mask_t))
 545                 return;
 546         spin_lock_irqsave(&sclp_lock, flags);
 547         if (scbuf->validity_sclp_receive_mask)
 548                 sclp_receive_mask = scbuf->sclp_receive_mask;
 549         if (scbuf->validity_sclp_send_mask)
 550                 sclp_send_mask = scbuf->sclp_send_mask;
 551         spin_unlock_irqrestore(&sclp_lock, flags);
 552         if (scbuf->validity_sclp_active_facility_mask)
 553                 sclp_facilities = scbuf->sclp_active_facility_mask;
 554         sclp_dispatch_state_change();
 555 }
 556
 557 static struct sclp_register sclp_state_change_event = {
 558         .receive_mask = EVTYP_STATECHANGE_MASK,
 559         .receiver_fn = sclp_state_change_cb
 560 };
 561
 562 /* Calculate receive and send mask of currently registered listeners.
 563  * Called while sclp_lock is locked. */
 564 static inline void
 565 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 566 {
 567         struct list_head *l;
 568         struct sclp_register *t;
 569
 570         *receive_mask = 0;
 571         *send_mask = 0;
 572         list_for_each(l, &sclp_reg_list) {
 573                 t = list_entry(l, struct sclp_register, list);
 574                 *receive_mask |= t->receive_mask;
 575                 *send_mask |= t->send_mask;
 576         }
 577 }
 578
 579 /* Register event listener. Return 0 on success, non-zero otherwise. */
 580 int
 581 sclp_register(struct sclp_register *reg)
 582 {
 583         unsigned long flags;
 584         sccb_mask_t receive_mask;
 585         sccb_mask_t send_mask;
 586         int rc;
 587
 588         rc = sclp_init();
 589         if (rc)
 590                 return rc;
 591         spin_lock_irqsave(&sclp_lock, flags);
 592         /* Check event mask for collisions */
 593         __sclp_get_mask(&receive_mask, &send_mask);
 594         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 595                 spin_unlock_irqrestore(&sclp_lock, flags);
 596                 return -EBUSY;
 597         }
 598         /* Trigger initial state change callback */
 599         reg->sclp_receive_mask = 0;
 600         reg->sclp_send_mask = 0;
 601         reg->pm_event_posted = 0;
 602         list_add(&reg->list, &sclp_reg_list);
 603         spin_unlock_irqrestore(&sclp_lock, flags);
 604         rc = sclp_init_mask(1);
 605         if (rc) {
 606                 spin_lock_irqsave(&sclp_lock, flags);
 607                 list_del(&reg->list);
 608                 spin_unlock_irqrestore(&sclp_lock, flags);
 609         }
 610         return rc;
 611 }
 612
 613 EXPORT_SYMBOL(sclp_register);
 614
 615 /* Unregister event listener. */
 616 void
 617 sclp_unregister(struct sclp_register *reg)
 618 {
 619         unsigned long flags;
 620
 621         spin_lock_irqsave(&sclp_lock, flags);
 622         list_del(&reg->list);
 623         spin_unlock_irqrestore(&sclp_lock, flags);
 624         sclp_init_mask(1);
 625 }
 626
 627 EXPORT_SYMBOL(sclp_unregister);
 628
 629 /* Remove event buffers which are marked processed. Return the number of
 630  * remaining event buffers. */
 631 int
 632 sclp_remove_processed(struct sccb_header *sccb)
 633 {
 634         struct evbuf_header *evbuf;
 635         int unprocessed;
 636         u16 remaining;
 637
 638         evbuf = (struct evbuf_header *) (sccb + 1);
 639         unprocessed = 0;
 640         remaining = sccb->length - sizeof(struct sccb_header);
 641         while (remaining > 0) {
 642                 remaining -= evbuf->length;
 643                 if (evbuf->flags & 0x80) {
 644                         sccb->length -= evbuf->length;
 645                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 646                                remaining);
 647                 } else {
 648                         unprocessed++;
 649                         evbuf = (struct evbuf_header *)
 650                                         ((addr_t) evbuf + evbuf->length);
 651                 }
 652         }
 653         return unprocessed;
 654 }
 655
 656 EXPORT_SYMBOL(sclp_remove_processed);
 657
 658 struct init_sccb {
 659         struct sccb_header header;
 660         u16 _reserved;
 661         u16 mask_length;
 662         sccb_mask_t receive_mask;
 663         sccb_mask_t send_mask;
 664         sccb_mask_t sclp_receive_mask;
 665         sccb_mask_t sclp_send_mask;
 666 } __attribute__((packed));
 667
 668 /* Prepare init mask request. Called while sclp_lock is locked. */
 669 static inline void
 670 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 671 {
 672         struct init_sccb *sccb;
 673
 674         sccb = (struct init_sccb *) sclp_init_sccb;
 675         clear_page(sccb);
 676         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 677         sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 678         sclp_init_req.status = SCLP_REQ_FILLED;
 679         sclp_init_req.start_count = 0;
 680         sclp_init_req.callback = NULL;
 681         sclp_init_req.callback_data = NULL;
 682         sclp_init_req.sccb = sccb;
 683         sccb->header.length = sizeof(struct init_sccb);
 684         sccb->mask_length = sizeof(sccb_mask_t);
 685         sccb->receive_mask = receive_mask;
 686         sccb->send_mask = send_mask;
 687         sccb->sclp_receive_mask = 0;
 688         sccb->sclp_send_mask = 0;
 689 }
 690
 691 /* Start init mask request. If calculate is non-zero, calculate the mask as
 692  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 693  * success, non-zero otherwise. */
 694 static int
 695 sclp_init_mask(int calculate)
 696 {
 697         unsigned long flags;
 698         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 699         sccb_mask_t receive_mask;
 700         sccb_mask_t send_mask;
 701         int retry;
 702         int rc;
 703         unsigned long wait;
 704
 705         spin_lock_irqsave(&sclp_lock, flags);
 706         /* Check if interface is in appropriate state */
 707         if (sclp_mask_state != sclp_mask_state_idle) {
 708                 spin_unlock_irqrestore(&sclp_lock, flags);
 709                 return -EBUSY;
 710         }
 711         if (sclp_activation_state == sclp_activation_state_inactive) {
 712                 spin_unlock_irqrestore(&sclp_lock, flags);
 713                 return -EINVAL;
 714         }
 715         sclp_mask_state = sclp_mask_state_initializing;
 716         /* Determine mask */
 717         if (calculate)
 718                 __sclp_get_mask(&receive_mask, &send_mask);
 719         else {
 720                 receive_mask = 0;
 721                 send_mask = 0;
 722         }
 723         rc = -EIO;
 724         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 725                 /* Prepare request */
 726                 __sclp_make_init_req(receive_mask, send_mask);
 727                 spin_unlock_irqrestore(&sclp_lock, flags);
 728                 if (sclp_add_request(&sclp_init_req)) {
 729                         /* Try again later */
 730                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 731                         while (time_before(jiffies, wait))
 732                                 sclp_sync_wait();
 733                         spin_lock_irqsave(&sclp_lock, flags);
 734                         continue;
 735                 }
 736                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 737                        sclp_init_req.status != SCLP_REQ_FAILED)
 738                         sclp_sync_wait();
 739                 spin_lock_irqsave(&sclp_lock, flags);
 740                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 741                     sccb->header.response_code == 0x20) {
 742                         /* Successful request */
 743                         if (calculate) {
 744                                 sclp_receive_mask = sccb->sclp_receive_mask;
 745                                 sclp_send_mask = sccb->sclp_send_mask;
 746                         } else {
 747                                 sclp_receive_mask = 0;
 748                                 sclp_send_mask = 0;
 749                         }
 750                         spin_unlock_irqrestore(&sclp_lock, flags);
 751                         sclp_dispatch_state_change();
 752                         spin_lock_irqsave(&sclp_lock, flags);
 753                         rc = 0;
 754                         break;
 755                 }
 756         }
 757         sclp_mask_state = sclp_mask_state_idle;
 758         spin_unlock_irqrestore(&sclp_lock, flags);
 759         return rc;
 760 }
 761
 762 /* Deactivate SCLP interface. On success, new requests will be rejected,
 763  * events will no longer be dispatched. Return 0 on success, non-zero
 764  * otherwise. */
 765 int
 766 sclp_deactivate(void)
 767 {
 768         unsigned long flags;
 769         int rc;
 770
 771         spin_lock_irqsave(&sclp_lock, flags);
 772         /* Deactivate can only be called when active */
 773         if (sclp_activation_state != sclp_activation_state_active) {
 774                 spin_unlock_irqrestore(&sclp_lock, flags);
 775                 return -EINVAL;
 776         }
 777         sclp_activation_state = sclp_activation_state_deactivating;
 778         spin_unlock_irqrestore(&sclp_lock, flags);
 779         rc = sclp_init_mask(0);
 780         spin_lock_irqsave(&sclp_lock, flags);
 781         if (rc == 0)
 782                 sclp_activation_state = sclp_activation_state_inactive;
 783         else
 784                 sclp_activation_state = sclp_activation_state_active;
 785         spin_unlock_irqrestore(&sclp_lock, flags);
 786         return rc;
 787 }
 788
 789 EXPORT_SYMBOL(sclp_deactivate);
 790
 791 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 792  * requests will be accepted, events will be dispatched again. Return 0 on
 793  * success, non-zero otherwise. */
 794 int
 795 sclp_reactivate(void)
 796 {
 797         unsigned long flags;
 798         int rc;
 799
 800         spin_lock_irqsave(&sclp_lock, flags);
 801         /* Reactivate can only be called when inactive */
 802         if (sclp_activation_state != sclp_activation_state_inactive) {
 803                 spin_unlock_irqrestore(&sclp_lock, flags);
 804                 return -EINVAL;
 805         }
 806         sclp_activation_state = sclp_activation_state_activating;
 807         spin_unlock_irqrestore(&sclp_lock, flags);
 808         rc = sclp_init_mask(1);
 809         spin_lock_irqsave(&sclp_lock, flags);
 810         if (rc == 0)
 811                 sclp_activation_state = sclp_activation_state_active;
 812         else
 813                 sclp_activation_state = sclp_activation_state_inactive;
 814         spin_unlock_irqrestore(&sclp_lock, flags);
 815         return rc;
 816 }
 817
 818 EXPORT_SYMBOL(sclp_reactivate);
 819
 820 /* Handler for external interruption used during initialization. Modify
 821  * request state to done. */
 822 static void sclp_check_handler(unsigned int ext_int_code,
 823                                unsigned int param32, unsigned long param64)
 824 {
 825         u32 finished_sccb;
 826
 827         kstat_cpu(smp_processor_id()).irqs[EXTINT_SCP]++;
 828         finished_sccb = param32 & 0xfffffff8;
 829         /* Is this the interrupt we are waiting for? */
 830         if (finished_sccb == 0)
 831                 return;
 832         if (finished_sccb != (u32) (addr_t) sclp_init_sccb)
 833                 panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
 834                       finished_sccb);
 835         spin_lock(&sclp_lock);
 836         if (sclp_running_state == sclp_running_state_running) {
 837                 sclp_init_req.status = SCLP_REQ_DONE;
 838                 sclp_running_state = sclp_running_state_idle;
 839         }
 840         spin_unlock(&sclp_lock);
 841 }
 842
 843 /* Initial init mask request timed out. Modify request state to failed. */
 844 static void
 845 sclp_check_timeout(unsigned long data)
 846 {
 847         unsigned long flags;
 848
 849         spin_lock_irqsave(&sclp_lock, flags);
 850         if (sclp_running_state == sclp_running_state_running) {
 851                 sclp_init_req.status = SCLP_REQ_FAILED;
 852                 sclp_running_state = sclp_running_state_idle;
 853         }
 854         spin_unlock_irqrestore(&sclp_lock, flags);
 855 }
 856
 857 /* Perform a check of the SCLP interface. Return zero if the interface is
 858  * available and there are no pending requests from a previous instance.
 859  * Return non-zero otherwise. */
 860 static int
 861 sclp_check_interface(void)
 862 {
 863         struct init_sccb *sccb;
 864         unsigned long flags;
 865         int retry;
 866         int rc;
 867
 868         spin_lock_irqsave(&sclp_lock, flags);
 869         /* Prepare init mask command */
 870         rc = register_external_interrupt(0x2401, sclp_check_handler);
 871         if (rc) {
 872                 spin_unlock_irqrestore(&sclp_lock, flags);
 873                 return rc;
 874         }
 875         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 876                 __sclp_make_init_req(0, 0);
 877                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 878                 rc = sclp_service_call(sclp_init_req.command, sccb);
 879                 if (rc == -EIO)
 880                         break;
 881                 sclp_init_req.status = SCLP_REQ_RUNNING;
 882                 sclp_running_state = sclp_running_state_running;
 883                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 884                                          sclp_check_timeout, 0);
 885                 spin_unlock_irqrestore(&sclp_lock, flags);
 886                 /* Enable service-signal interruption - needs to happen
 887                  * with IRQs enabled. */
 888                 ctl_set_bit(0, 9);
 889                 /* Wait for signal from interrupt or timeout */
 890                 sclp_sync_wait();
 891                 /* Disable service-signal interruption - needs to happen
 892                  * with IRQs enabled. */
 893                 ctl_clear_bit(0,9);
 894                 spin_lock_irqsave(&sclp_lock, flags);
 895                 del_timer(&sclp_request_timer);
 896                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 897                     sccb->header.response_code == 0x20) {
 898                         rc = 0;
 899                         break;
 900                 } else
 901                         rc = -EBUSY;
 902         }
 903         unregister_external_interrupt(0x2401, sclp_check_handler);
 904         spin_unlock_irqrestore(&sclp_lock, flags);
 905         return rc;
 906 }
 907
 908 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 909  * events from interfering with rebooted system. */
 910 static int
 911 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 912 {
 913         sclp_deactivate();
 914         return NOTIFY_DONE;
 915 }
 916
 917 static struct notifier_block sclp_reboot_notifier = {
 918         .notifier_call = sclp_reboot_event
 919 };
 920
 921 /*
 922  * Suspend/resume SCLP notifier implementation
 923  */
 924
 925 static void sclp_pm_event(enum sclp_pm_event sclp_pm_event, int rollback)
 926 {
 927         struct sclp_register *reg;
 928         unsigned long flags;
 929
 930         if (!rollback) {
 931                 spin_lock_irqsave(&sclp_lock, flags);
 932                 list_for_each_entry(reg, &sclp_reg_list, list)
 933                         reg->pm_event_posted = 0;
 934                 spin_unlock_irqrestore(&sclp_lock, flags);
 935         }
 936         do {
 937                 spin_lock_irqsave(&sclp_lock, flags);
 938                 list_for_each_entry(reg, &sclp_reg_list, list) {
 939                         if (rollback && reg->pm_event_posted)
 940                                 goto found;
 941                         if (!rollback && !reg->pm_event_posted)
 942                                 goto found;
 943                 }
 944                 spin_unlock_irqrestore(&sclp_lock, flags);
 945                 return;
 946 found:
 947                 spin_unlock_irqrestore(&sclp_lock, flags);
 948                 if (reg->pm_event_fn)
 949                         reg->pm_event_fn(reg, sclp_pm_event);
 950                 reg->pm_event_posted = rollback ? 0 : 1;
 951         } while (1);
 952 }
 953
 954 /*
 955  * Susend/resume callbacks for platform device
 956  */
 957
 958 static int sclp_freeze(struct device *dev)
 959 {
 960         unsigned long flags;
 961         int rc;
 962
 963         sclp_pm_event(SCLP_PM_EVENT_FREEZE, 0);
 964
 965         spin_lock_irqsave(&sclp_lock, flags);
 966         sclp_suspend_state = sclp_suspend_state_suspended;
 967         spin_unlock_irqrestore(&sclp_lock, flags);
 968
 969         /* Init supend data */
 970         memset(&sclp_suspend_req, 0, sizeof(sclp_suspend_req));
 971         sclp_suspend_req.callback = sclp_suspend_req_cb;
 972         sclp_suspend_req.status = SCLP_REQ_FILLED;
 973         init_completion(&sclp_request_queue_flushed);
 974
 975         rc = sclp_add_request(&sclp_suspend_req);
 976         if (rc == 0)
 977                 wait_for_completion(&sclp_request_queue_flushed);
 978         else if (rc != -ENODATA)
 979                 goto fail_thaw;
 980
 981         rc = sclp_deactivate();
 982         if (rc)
 983                 goto fail_thaw;
 984         return 0;
 985
 986 fail_thaw:
 987         spin_lock_irqsave(&sclp_lock, flags);
 988         sclp_suspend_state = sclp_suspend_state_running;
 989         spin_unlock_irqrestore(&sclp_lock, flags);
 990         sclp_pm_event(SCLP_PM_EVENT_THAW, 1);
 991         return rc;
 992 }
 993
 994 static int sclp_undo_suspend(enum sclp_pm_event event)
 995 {
 996         unsigned long flags;
 997         int rc;
 998
 999         rc = sclp_reactivate();
1000         if (rc)
1001                 return rc;
1002
1003         spin_lock_irqsave(&sclp_lock, flags);
1004         sclp_suspend_state = sclp_suspend_state_running;
1005         spin_unlock_irqrestore(&sclp_lock, flags);
1006
1007         sclp_pm_event(event, 0);
1008         return 0;
1009 }
1010
1011 static int sclp_thaw(struct device *dev)
1012 {
1013         return sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1014 }
1015
1016 static int sclp_restore(struct device *dev)
1017 {
1018         return sclp_undo_suspend(SCLP_PM_EVENT_RESTORE);
1019 }
1020
1021 static const struct dev_pm_ops sclp_pm_ops = {
1022         .freeze         = sclp_freeze,
1023         .thaw           = sclp_thaw,
1024         .restore        = sclp_restore,
1025 };
1026
1027 static struct platform_driver sclp_pdrv = {
1028         .driver = {
1029                 .name   = "sclp",
1030                 .owner  = THIS_MODULE,
1031                 .pm     = &sclp_pm_ops,
1032         },
1033 };
1034
1035 static struct platform_device *sclp_pdev;
1036
1037 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
1038  * otherwise. */
1039 static int
1040 sclp_init(void)
1041 {
1042         unsigned long flags;
1043         int rc = 0;
1044
1045         spin_lock_irqsave(&sclp_lock, flags);
1046         /* Check for previous or running initialization */
1047         if (sclp_init_state != sclp_init_state_uninitialized)
1048                 goto fail_unlock;
1049         sclp_init_state = sclp_init_state_initializing;
1050         /* Set up variables */
1051         INIT_LIST_HEAD(&sclp_req_queue);
1052         INIT_LIST_HEAD(&sclp_reg_list);
1053         list_add(&sclp_state_change_event.list, &sclp_reg_list);
1054         init_timer(&sclp_request_timer);
1055         /* Check interface */
1056         spin_unlock_irqrestore(&sclp_lock, flags);
1057         rc = sclp_check_interface();
1058         spin_lock_irqsave(&sclp_lock, flags);
1059         if (rc)
1060                 goto fail_init_state_uninitialized;
1061         /* Register reboot handler */
1062         rc = register_reboot_notifier(&sclp_reboot_notifier);
1063         if (rc)
1064                 goto fail_init_state_uninitialized;
1065         /* Register interrupt handler */
1066         rc = register_external_interrupt(0x2401, sclp_interrupt_handler);
1067         if (rc)
1068                 goto fail_unregister_reboot_notifier;
1069         sclp_init_state = sclp_init_state_initialized;
1070         spin_unlock_irqrestore(&sclp_lock, flags);
1071         /* Enable service-signal external interruption - needs to happen with
1072          * IRQs enabled. */
1073         ctl_set_bit(0, 9);
1074         sclp_init_mask(1);
1075         return 0;
1076
1077 fail_unregister_reboot_notifier:
1078         unregister_reboot_notifier(&sclp_reboot_notifier);
1079 fail_init_state_uninitialized:
1080         sclp_init_state = sclp_init_state_uninitialized;
1081 fail_unlock:
1082         spin_unlock_irqrestore(&sclp_lock, flags);
1083         return rc;
1084 }
1085
1086 /*
1087  * SCLP panic notifier: If we are suspended, we thaw SCLP in order to be able
1088  * to print the panic message.
1089  */
1090 static int sclp_panic_notify(struct notifier_block *self,
1091                              unsigned long event, void *data)
1092 {
1093         if (sclp_suspend_state == sclp_suspend_state_suspended)
1094                 sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1095         return NOTIFY_OK;
1096 }
1097
1098 static struct notifier_block sclp_on_panic_nb = {
1099         .notifier_call = sclp_panic_notify,
1100         .priority = SCLP_PANIC_PRIO,
1101 };
1102
1103 static __init int sclp_initcall(void)
1104 {
1105         int rc;
1106
1107         rc = platform_driver_register(&sclp_pdrv);
1108         if (rc)
1109                 return rc;
1110         sclp_pdev = platform_device_register_simple("sclp", -1, NULL, 0);
1111         rc = IS_ERR(sclp_pdev) ? PTR_ERR(sclp_pdev) : 0;
1112         if (rc)
1113                 goto fail_platform_driver_unregister;
1114         rc = atomic_notifier_chain_register(&panic_notifier_list,
1115                                             &sclp_on_panic_nb);
1116         if (rc)
1117                 goto fail_platform_device_unregister;
1118
1119         return sclp_init();
1120
1121 fail_platform_device_unregister:
1122         platform_device_unregister(sclp_pdev);
1123 fail_platform_driver_unregister:
1124         platform_driver_unregister(&sclp_pdrv);
1125         return rc;
1126 }
1127
1128 arch_initcall(sclp_initcall);