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 static void sclp_suspend_req_cb(struct sclp_req *req, void *data)
  54 {
  55         complete(&sclp_request_queue_flushed);
  56 }
  57
  58 static struct sclp_req sclp_suspend_req;
  59
  60 /* Timer for request retries. */
  61 static struct timer_list sclp_request_timer;
  62
  63 /* Internal state: is the driver initialized? */
  64 static volatile enum sclp_init_state_t {
  65         sclp_init_state_uninitialized,
  66         sclp_init_state_initializing,
  67         sclp_init_state_initialized
  68 } sclp_init_state = sclp_init_state_uninitialized;
  69
  70 /* Internal state: is a request active at the sclp? */
  71 static volatile enum sclp_running_state_t {
  72         sclp_running_state_idle,
  73         sclp_running_state_running,
  74         sclp_running_state_reset_pending
  75 } sclp_running_state = sclp_running_state_idle;
  76
  77 /* Internal state: is a read request pending? */
  78 static volatile enum sclp_reading_state_t {
  79         sclp_reading_state_idle,
  80         sclp_reading_state_reading
  81 } sclp_reading_state = sclp_reading_state_idle;
  82
  83 /* Internal state: is the driver currently serving requests? */
  84 static volatile enum sclp_activation_state_t {
  85         sclp_activation_state_active,
  86         sclp_activation_state_deactivating,
  87         sclp_activation_state_inactive,
  88         sclp_activation_state_activating
  89 } sclp_activation_state = sclp_activation_state_active;
  90
  91 /* Internal state: is an init mask request pending? */
  92 static volatile enum sclp_mask_state_t {
  93         sclp_mask_state_idle,
  94         sclp_mask_state_initializing
  95 } sclp_mask_state = sclp_mask_state_idle;
  96
  97 /* Internal state: is the driver suspended? */
  98 static enum sclp_suspend_state_t {
  99         sclp_suspend_state_running,
 100         sclp_suspend_state_suspended,
 101 } sclp_suspend_state = sclp_suspend_state_running;
 102
 103 /* Maximum retry counts */
 104 #define SCLP_INIT_RETRY         3
 105 #define SCLP_MASK_RETRY         3
 106
 107 /* Timeout intervals in seconds.*/
 108 #define SCLP_BUSY_INTERVAL      10
 109 #define SCLP_RETRY_INTERVAL     30
 110
 111 static void sclp_process_queue(void);
 112 static void __sclp_make_read_req(void);
 113 static int sclp_init_mask(int calculate);
 114 static int sclp_init(void);
 115
 116 /* Perform service call. Return 0 on success, non-zero otherwise. */
 117 int
 118 sclp_service_call(sclp_cmdw_t command, void *sccb)
 119 {
 120         int cc;
 121
 122         asm volatile(
 123                 "       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
 124                 "       ipm     %0\n"
 125                 "       srl     %0,28"
 126                 : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
 127                 : "cc", "memory");
 128         if (cc == 3)
 129                 return -EIO;
 130         if (cc == 2)
 131                 return -EBUSY;
 132         return 0;
 133 }
 134
 135
 136 static void
 137 __sclp_queue_read_req(void)
 138 {
 139         if (sclp_reading_state == sclp_reading_state_idle) {
 140                 sclp_reading_state = sclp_reading_state_reading;
 141                 __sclp_make_read_req();
 142                 /* Add request to head of queue */
 143                 list_add(&sclp_read_req.list, &sclp_req_queue);
 144         }
 145 }
 146
 147 /* Set up request retry timer. Called while sclp_lock is locked. */
 148 static inline void
 149 __sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
 150                          unsigned long data)
 151 {
 152         del_timer(&sclp_request_timer);
 153         sclp_request_timer.function = function;
 154         sclp_request_timer.data = data;
 155         sclp_request_timer.expires = jiffies + time;
 156         add_timer(&sclp_request_timer);
 157 }
 158
 159 /* Request timeout handler. Restart the request queue. If DATA is non-zero,
 160  * force restart of running request. */
 161 static void
 162 sclp_request_timeout(unsigned long data)
 163 {
 164         unsigned long flags;
 165
 166         spin_lock_irqsave(&sclp_lock, flags);
 167         if (data) {
 168                 if (sclp_running_state == sclp_running_state_running) {
 169                         /* Break running state and queue NOP read event request
 170                          * to get a defined interface state. */
 171                         __sclp_queue_read_req();
 172                         sclp_running_state = sclp_running_state_idle;
 173                 }
 174         } else {
 175                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 176                                          sclp_request_timeout, 0);
 177         }
 178         spin_unlock_irqrestore(&sclp_lock, flags);
 179         sclp_process_queue();
 180 }
 181
 182 /* Try to start a request. Return zero if the request was successfully
 183  * started or if it will be started at a later time. Return non-zero otherwise.
 184  * Called while sclp_lock is locked. */
 185 static int
 186 __sclp_start_request(struct sclp_req *req)
 187 {
 188         int rc;
 189
 190         if (sclp_running_state != sclp_running_state_idle)
 191                 return 0;
 192         del_timer(&sclp_request_timer);
 193         rc = sclp_service_call(req->command, req->sccb);
 194         req->start_count++;
 195
 196         if (rc == 0) {
 197                 /* Successfully started request */
 198                 req->status = SCLP_REQ_RUNNING;
 199                 sclp_running_state = sclp_running_state_running;
 200                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 201                                          sclp_request_timeout, 1);
 202                 return 0;
 203         } else if (rc == -EBUSY) {
 204                 /* Try again later */
 205                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 206                                          sclp_request_timeout, 0);
 207                 return 0;
 208         }
 209         /* Request failed */
 210         req->status = SCLP_REQ_FAILED;
 211         return rc;
 212 }
 213
 214 /* Try to start queued requests. */
 215 static void
 216 sclp_process_queue(void)
 217 {
 218         struct sclp_req *req;
 219         int rc;
 220         unsigned long flags;
 221
 222         spin_lock_irqsave(&sclp_lock, flags);
 223         if (sclp_running_state != sclp_running_state_idle) {
 224                 spin_unlock_irqrestore(&sclp_lock, flags);
 225                 return;
 226         }
 227         del_timer(&sclp_request_timer);
 228         while (!list_empty(&sclp_req_queue)) {
 229                 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
 230                 if (!req->sccb)
 231                         goto do_post;
 232                 rc = __sclp_start_request(req);
 233                 if (rc == 0)
 234                         break;
 235                 /* Request failed */
 236                 if (req->start_count > 1) {
 237                         /* Cannot abort already submitted request - could still
 238                          * be active at the SCLP */
 239                         __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 240                                                  sclp_request_timeout, 0);
 241                         break;
 242                 }
 243 do_post:
 244                 /* Post-processing for aborted request */
 245                 list_del(&req->list);
 246                 if (req->callback) {
 247                         spin_unlock_irqrestore(&sclp_lock, flags);
 248                         req->callback(req, req->callback_data);
 249                         spin_lock_irqsave(&sclp_lock, flags);
 250                 }
 251         }
 252         spin_unlock_irqrestore(&sclp_lock, flags);
 253 }
 254
 255 static int __sclp_can_add_request(struct sclp_req *req)
 256 {
 257         if (req == &sclp_suspend_req || req == &sclp_init_req)
 258                 return 1;
 259         if (sclp_suspend_state != sclp_suspend_state_running)
 260                 return 0;
 261         if (sclp_init_state != sclp_init_state_initialized)
 262                 return 0;
 263         if (sclp_activation_state != sclp_activation_state_active)
 264                 return 0;
 265         return 1;
 266 }
 267
 268 /* Queue a new request. Return zero on success, non-zero otherwise. */
 269 int
 270 sclp_add_request(struct sclp_req *req)
 271 {
 272         unsigned long flags;
 273         int rc;
 274
 275         spin_lock_irqsave(&sclp_lock, flags);
 276         if (!__sclp_can_add_request(req)) {
 277                 spin_unlock_irqrestore(&sclp_lock, flags);
 278                 return -EIO;
 279         }
 280         req->status = SCLP_REQ_QUEUED;
 281         req->start_count = 0;
 282         list_add_tail(&req->list, &sclp_req_queue);
 283         rc = 0;
 284         /* Start if request is first in list */
 285         if (sclp_running_state == sclp_running_state_idle &&
 286             req->list.prev == &sclp_req_queue) {
 287                 if (!req->sccb) {
 288                         list_del(&req->list);
 289                         rc = -ENODATA;
 290                         goto out;
 291                 }
 292                 rc = __sclp_start_request(req);
 293                 if (rc)
 294                         list_del(&req->list);
 295         }
 296 out:
 297         spin_unlock_irqrestore(&sclp_lock, flags);
 298         return rc;
 299 }
 300
 301 EXPORT_SYMBOL(sclp_add_request);
 302
 303 /* Dispatch events found in request buffer to registered listeners. Return 0
 304  * if all events were dispatched, non-zero otherwise. */
 305 static int
 306 sclp_dispatch_evbufs(struct sccb_header *sccb)
 307 {
 308         unsigned long flags;
 309         struct evbuf_header *evbuf;
 310         struct list_head *l;
 311         struct sclp_register *reg;
 312         int offset;
 313         int rc;
 314
 315         spin_lock_irqsave(&sclp_lock, flags);
 316         rc = 0;
 317         for (offset = sizeof(struct sccb_header); offset < sccb->length;
 318              offset += evbuf->length) {
 319                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 320                 /* Check for malformed hardware response */
 321                 if (evbuf->length == 0)
 322                         break;
 323                 /* Search for event handler */
 324                 reg = NULL;
 325                 list_for_each(l, &sclp_reg_list) {
 326                         reg = list_entry(l, struct sclp_register, list);
 327                         if (reg->receive_mask & (1 << (32 - evbuf->type)))
 328                                 break;
 329                         else
 330                                 reg = NULL;
 331                 }
 332                 if (reg && reg->receiver_fn) {
 333                         spin_unlock_irqrestore(&sclp_lock, flags);
 334                         reg->receiver_fn(evbuf);
 335                         spin_lock_irqsave(&sclp_lock, flags);
 336                 } else if (reg == NULL)
 337                         rc = -ENOSYS;
 338         }
 339         spin_unlock_irqrestore(&sclp_lock, flags);
 340         return rc;
 341 }
 342
 343 /* Read event data request callback. */
 344 static void
 345 sclp_read_cb(struct sclp_req *req, void *data)
 346 {
 347         unsigned long flags;
 348         struct sccb_header *sccb;
 349
 350         sccb = (struct sccb_header *) req->sccb;
 351         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 352             sccb->response_code == 0x220))
 353                 sclp_dispatch_evbufs(sccb);
 354         spin_lock_irqsave(&sclp_lock, flags);
 355         sclp_reading_state = sclp_reading_state_idle;
 356         spin_unlock_irqrestore(&sclp_lock, flags);
 357 }
 358
 359 /* Prepare read event data request. Called while sclp_lock is locked. */
 360 static void __sclp_make_read_req(void)
 361 {
 362         struct sccb_header *sccb;
 363
 364         sccb = (struct sccb_header *) sclp_read_sccb;
 365         clear_page(sccb);
 366         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 367         sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
 368         sclp_read_req.status = SCLP_REQ_QUEUED;
 369         sclp_read_req.start_count = 0;
 370         sclp_read_req.callback = sclp_read_cb;
 371         sclp_read_req.sccb = sccb;
 372         sccb->length = PAGE_SIZE;
 373         sccb->function_code = 0;
 374         sccb->control_mask[2] = 0x80;
 375 }
 376
 377 /* Search request list for request with matching sccb. Return request if found,
 378  * NULL otherwise. Called while sclp_lock is locked. */
 379 static inline struct sclp_req *
 380 __sclp_find_req(u32 sccb)
 381 {
 382         struct list_head *l;
 383         struct sclp_req *req;
 384
 385         list_for_each(l, &sclp_req_queue) {
 386                 req = list_entry(l, struct sclp_req, list);
 387                 if (sccb == (u32) (addr_t) req->sccb)
 388                                 return req;
 389         }
 390         return NULL;
 391 }
 392
 393 /* Handler for external interruption. Perform request post-processing.
 394  * Prepare read event data request if necessary. Start processing of next
 395  * request on queue. */
 396 static void sclp_interrupt_handler(unsigned int ext_int_code,
 397                                    unsigned int param32, unsigned long param64)
 398 {
 399         struct sclp_req *req;
 400         u32 finished_sccb;
 401         u32 evbuf_pending;
 402
 403         kstat_cpu(smp_processor_id()).irqs[EXTINT_SCP]++;
 404         spin_lock(&sclp_lock);
 405         finished_sccb = param32 & 0xfffffff8;
 406         evbuf_pending = param32 & 0x3;
 407         if (finished_sccb) {
 408                 del_timer(&sclp_request_timer);
 409                 sclp_running_state = sclp_running_state_reset_pending;
 410                 req = __sclp_find_req(finished_sccb);
 411                 if (req) {
 412                         /* Request post-processing */
 413                         list_del(&req->list);
 414                         req->status = SCLP_REQ_DONE;
 415                         if (req->callback) {
 416                                 spin_unlock(&sclp_lock);
 417                                 req->callback(req, req->callback_data);
 418                                 spin_lock(&sclp_lock);
 419                         }
 420                 }
 421                 sclp_running_state = sclp_running_state_idle;
 422         }
 423         if (evbuf_pending &&
 424             sclp_activation_state == sclp_activation_state_active)
 425                 __sclp_queue_read_req();
 426         spin_unlock(&sclp_lock);
 427         sclp_process_queue();
 428 }
 429
 430 /* Convert interval in jiffies to TOD ticks. */
 431 static inline u64
 432 sclp_tod_from_jiffies(unsigned long jiffies)
 433 {
 434         return (u64) (jiffies / HZ) << 32;
 435 }
 436
 437 /* Wait until a currently running request finished. Note: while this function
 438  * is running, no timers are served on the calling CPU. */
 439 void
 440 sclp_sync_wait(void)
 441 {
 442         unsigned long long old_tick;
 443         unsigned long flags;
 444         unsigned long cr0, cr0_sync;
 445         u64 timeout;
 446         int irq_context;
 447
 448         /* We'll be disabling timer interrupts, so we need a custom timeout
 449          * mechanism */
 450         timeout = 0;
 451         if (timer_pending(&sclp_request_timer)) {
 452                 /* Get timeout TOD value */
 453                 timeout = get_clock() +
 454                           sclp_tod_from_jiffies(sclp_request_timer.expires -
 455                                                 jiffies);
 456         }
 457         local_irq_save(flags);
 458         /* Prevent bottom half from executing once we force interrupts open */
 459         irq_context = in_interrupt();
 460         if (!irq_context)
 461                 local_bh_disable();
 462         /* Enable service-signal interruption, disable timer interrupts */
 463         old_tick = local_tick_disable();
 464         trace_hardirqs_on();
 465         __ctl_store(cr0, 0, 0);
 466         cr0_sync = cr0;
 467         cr0_sync &= 0xffff00a0;
 468         cr0_sync |= 0x00000200;
 469         __ctl_load(cr0_sync, 0, 0);
 470         __arch_local_irq_stosm(0x01);
 471         /* Loop until driver state indicates finished request */
 472         while (sclp_running_state != sclp_running_state_idle) {
 473                 /* Check for expired request timer */
 474                 if (timer_pending(&sclp_request_timer) &&
 475                     get_clock() > timeout &&
 476                     del_timer(&sclp_request_timer))
 477                         sclp_request_timer.function(sclp_request_timer.data);
 478                 cpu_relax();
 479         }
 480         local_irq_disable();
 481         __ctl_load(cr0, 0, 0);
 482         if (!irq_context)
 483                 _local_bh_enable();
 484         local_tick_enable(old_tick);
 485         local_irq_restore(flags);
 486 }
 487 EXPORT_SYMBOL(sclp_sync_wait);
 488
 489 /* Dispatch changes in send and receive mask to registered listeners. */
 490 static void
 491 sclp_dispatch_state_change(void)
 492 {
 493         struct list_head *l;
 494         struct sclp_register *reg;
 495         unsigned long flags;
 496         sccb_mask_t receive_mask;
 497         sccb_mask_t send_mask;
 498
 499         do {
 500                 spin_lock_irqsave(&sclp_lock, flags);
 501                 reg = NULL;
 502                 list_for_each(l, &sclp_reg_list) {
 503                         reg = list_entry(l, struct sclp_register, list);
 504                         receive_mask = reg->send_mask & sclp_receive_mask;
 505                         send_mask = reg->receive_mask & sclp_send_mask;
 506                         if (reg->sclp_receive_mask != receive_mask ||
 507                             reg->sclp_send_mask != send_mask) {
 508                                 reg->sclp_receive_mask = receive_mask;
 509                                 reg->sclp_send_mask = send_mask;
 510                                 break;
 511                         } else
 512                                 reg = NULL;
 513                 }
 514                 spin_unlock_irqrestore(&sclp_lock, flags);
 515                 if (reg && reg->state_change_fn)
 516                         reg->state_change_fn(reg);
 517         } while (reg);
 518 }
 519
 520 struct sclp_statechangebuf {
 521         struct evbuf_header     header;
 522         u8              validity_sclp_active_facility_mask : 1;
 523         u8              validity_sclp_receive_mask : 1;
 524         u8              validity_sclp_send_mask : 1;
 525         u8              validity_read_data_function_mask : 1;
 526         u16             _zeros : 12;
 527         u16             mask_length;
 528         u64             sclp_active_facility_mask;
 529         sccb_mask_t     sclp_receive_mask;
 530         sccb_mask_t     sclp_send_mask;
 531         u32             read_data_function_mask;
 532 } __attribute__((packed));
 533
 534
 535 /* State change event callback. Inform listeners of changes. */
 536 static void
 537 sclp_state_change_cb(struct evbuf_header *evbuf)
 538 {
 539         unsigned long flags;
 540         struct sclp_statechangebuf *scbuf;
 541
 542         scbuf = (struct sclp_statechangebuf *) evbuf;
 543         if (scbuf->mask_length != sizeof(sccb_mask_t))
 544                 return;
 545         spin_lock_irqsave(&sclp_lock, flags);
 546         if (scbuf->validity_sclp_receive_mask)
 547                 sclp_receive_mask = scbuf->sclp_receive_mask;
 548         if (scbuf->validity_sclp_send_mask)
 549                 sclp_send_mask = scbuf->sclp_send_mask;
 550         spin_unlock_irqrestore(&sclp_lock, flags);
 551         if (scbuf->validity_sclp_active_facility_mask)
 552                 sclp_facilities = scbuf->sclp_active_facility_mask;
 553         sclp_dispatch_state_change();
 554 }
 555
 556 static struct sclp_register sclp_state_change_event = {
 557         .receive_mask = EVTYP_STATECHANGE_MASK,
 558         .receiver_fn = sclp_state_change_cb
 559 };
 560
 561 /* Calculate receive and send mask of currently registered listeners.
 562  * Called while sclp_lock is locked. */
 563 static inline void
 564 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 565 {
 566         struct list_head *l;
 567         struct sclp_register *t;
 568
 569         *receive_mask = 0;
 570         *send_mask = 0;
 571         list_for_each(l, &sclp_reg_list) {
 572                 t = list_entry(l, struct sclp_register, list);
 573                 *receive_mask |= t->receive_mask;
 574                 *send_mask |= t->send_mask;
 575         }
 576 }
 577
 578 /* Register event listener. Return 0 on success, non-zero otherwise. */
 579 int
 580 sclp_register(struct sclp_register *reg)
 581 {
 582         unsigned long flags;
 583         sccb_mask_t receive_mask;
 584         sccb_mask_t send_mask;
 585         int rc;
 586
 587         rc = sclp_init();
 588         if (rc)
 589                 return rc;
 590         spin_lock_irqsave(&sclp_lock, flags);
 591         /* Check event mask for collisions */
 592         __sclp_get_mask(&receive_mask, &send_mask);
 593         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 594                 spin_unlock_irqrestore(&sclp_lock, flags);
 595                 return -EBUSY;
 596         }
 597         /* Trigger initial state change callback */
 598         reg->sclp_receive_mask = 0;
 599         reg->sclp_send_mask = 0;
 600         reg->pm_event_posted = 0;
 601         list_add(&reg->list, &sclp_reg_list);
 602         spin_unlock_irqrestore(&sclp_lock, flags);
 603         rc = sclp_init_mask(1);
 604         if (rc) {
 605                 spin_lock_irqsave(&sclp_lock, flags);
 606                 list_del(&reg->list);
 607                 spin_unlock_irqrestore(&sclp_lock, flags);
 608         }
 609         return rc;
 610 }
 611
 612 EXPORT_SYMBOL(sclp_register);
 613
 614 /* Unregister event listener. */
 615 void
 616 sclp_unregister(struct sclp_register *reg)
 617 {
 618         unsigned long flags;
 619
 620         spin_lock_irqsave(&sclp_lock, flags);
 621         list_del(&reg->list);
 622         spin_unlock_irqrestore(&sclp_lock, flags);
 623         sclp_init_mask(1);
 624 }
 625
 626 EXPORT_SYMBOL(sclp_unregister);
 627
 628 /* Remove event buffers which are marked processed. Return the number of
 629  * remaining event buffers. */
 630 int
 631 sclp_remove_processed(struct sccb_header *sccb)
 632 {
 633         struct evbuf_header *evbuf;
 634         int unprocessed;
 635         u16 remaining;
 636
 637         evbuf = (struct evbuf_header *) (sccb + 1);
 638         unprocessed = 0;
 639         remaining = sccb->length - sizeof(struct sccb_header);
 640         while (remaining > 0) {
 641                 remaining -= evbuf->length;
 642                 if (evbuf->flags & 0x80) {
 643                         sccb->length -= evbuf->length;
 644                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 645                                remaining);
 646                 } else {
 647                         unprocessed++;
 648                         evbuf = (struct evbuf_header *)
 649                                         ((addr_t) evbuf + evbuf->length);
 650                 }
 651         }
 652         return unprocessed;
 653 }
 654
 655 EXPORT_SYMBOL(sclp_remove_processed);
 656
 657 struct init_sccb {
 658         struct sccb_header header;
 659         u16 _reserved;
 660         u16 mask_length;
 661         sccb_mask_t receive_mask;
 662         sccb_mask_t send_mask;
 663         sccb_mask_t sclp_receive_mask;
 664         sccb_mask_t sclp_send_mask;
 665 } __attribute__((packed));
 666
 667 /* Prepare init mask request. Called while sclp_lock is locked. */
 668 static inline void
 669 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 670 {
 671         struct init_sccb *sccb;
 672
 673         sccb = (struct init_sccb *) sclp_init_sccb;
 674         clear_page(sccb);
 675         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 676         sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 677         sclp_init_req.status = SCLP_REQ_FILLED;
 678         sclp_init_req.start_count = 0;
 679         sclp_init_req.callback = NULL;
 680         sclp_init_req.callback_data = NULL;
 681         sclp_init_req.sccb = sccb;
 682         sccb->header.length = sizeof(struct init_sccb);
 683         sccb->mask_length = sizeof(sccb_mask_t);
 684         sccb->receive_mask = receive_mask;
 685         sccb->send_mask = send_mask;
 686         sccb->sclp_receive_mask = 0;
 687         sccb->sclp_send_mask = 0;
 688 }
 689
 690 /* Start init mask request. If calculate is non-zero, calculate the mask as
 691  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 692  * success, non-zero otherwise. */
 693 static int
 694 sclp_init_mask(int calculate)
 695 {
 696         unsigned long flags;
 697         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 698         sccb_mask_t receive_mask;
 699         sccb_mask_t send_mask;
 700         int retry;
 701         int rc;
 702         unsigned long wait;
 703
 704         spin_lock_irqsave(&sclp_lock, flags);
 705         /* Check if interface is in appropriate state */
 706         if (sclp_mask_state != sclp_mask_state_idle) {
 707                 spin_unlock_irqrestore(&sclp_lock, flags);
 708                 return -EBUSY;
 709         }
 710         if (sclp_activation_state == sclp_activation_state_inactive) {
 711                 spin_unlock_irqrestore(&sclp_lock, flags);
 712                 return -EINVAL;
 713         }
 714         sclp_mask_state = sclp_mask_state_initializing;
 715         /* Determine mask */
 716         if (calculate)
 717                 __sclp_get_mask(&receive_mask, &send_mask);
 718         else {
 719                 receive_mask = 0;
 720                 send_mask = 0;
 721         }
 722         rc = -EIO;
 723         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 724                 /* Prepare request */
 725                 __sclp_make_init_req(receive_mask, send_mask);
 726                 spin_unlock_irqrestore(&sclp_lock, flags);
 727                 if (sclp_add_request(&sclp_init_req)) {
 728                         /* Try again later */
 729                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 730                         while (time_before(jiffies, wait))
 731                                 sclp_sync_wait();
 732                         spin_lock_irqsave(&sclp_lock, flags);
 733                         continue;
 734                 }
 735                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 736                        sclp_init_req.status != SCLP_REQ_FAILED)
 737                         sclp_sync_wait();
 738                 spin_lock_irqsave(&sclp_lock, flags);
 739                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 740                     sccb->header.response_code == 0x20) {
 741                         /* Successful request */
 742                         if (calculate) {
 743                                 sclp_receive_mask = sccb->sclp_receive_mask;
 744                                 sclp_send_mask = sccb->sclp_send_mask;
 745                         } else {
 746                                 sclp_receive_mask = 0;
 747                                 sclp_send_mask = 0;
 748                         }
 749                         spin_unlock_irqrestore(&sclp_lock, flags);
 750                         sclp_dispatch_state_change();
 751                         spin_lock_irqsave(&sclp_lock, flags);
 752                         rc = 0;
 753                         break;
 754                 }
 755         }
 756         sclp_mask_state = sclp_mask_state_idle;
 757         spin_unlock_irqrestore(&sclp_lock, flags);
 758         return rc;
 759 }
 760
 761 /* Deactivate SCLP interface. On success, new requests will be rejected,
 762  * events will no longer be dispatched. Return 0 on success, non-zero
 763  * otherwise. */
 764 int
 765 sclp_deactivate(void)
 766 {
 767         unsigned long flags;
 768         int rc;
 769
 770         spin_lock_irqsave(&sclp_lock, flags);
 771         /* Deactivate can only be called when active */
 772         if (sclp_activation_state != sclp_activation_state_active) {
 773                 spin_unlock_irqrestore(&sclp_lock, flags);
 774                 return -EINVAL;
 775         }
 776         sclp_activation_state = sclp_activation_state_deactivating;
 777         spin_unlock_irqrestore(&sclp_lock, flags);
 778         rc = sclp_init_mask(0);
 779         spin_lock_irqsave(&sclp_lock, flags);
 780         if (rc == 0)
 781                 sclp_activation_state = sclp_activation_state_inactive;
 782         else
 783                 sclp_activation_state = sclp_activation_state_active;
 784         spin_unlock_irqrestore(&sclp_lock, flags);
 785         return rc;
 786 }
 787
 788 EXPORT_SYMBOL(sclp_deactivate);
 789
 790 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 791  * requests will be accepted, events will be dispatched again. Return 0 on
 792  * success, non-zero otherwise. */
 793 int
 794 sclp_reactivate(void)
 795 {
 796         unsigned long flags;
 797         int rc;
 798
 799         spin_lock_irqsave(&sclp_lock, flags);
 800         /* Reactivate can only be called when inactive */
 801         if (sclp_activation_state != sclp_activation_state_inactive) {
 802                 spin_unlock_irqrestore(&sclp_lock, flags);
 803                 return -EINVAL;
 804         }
 805         sclp_activation_state = sclp_activation_state_activating;
 806         spin_unlock_irqrestore(&sclp_lock, flags);
 807         rc = sclp_init_mask(1);
 808         spin_lock_irqsave(&sclp_lock, flags);
 809         if (rc == 0)
 810                 sclp_activation_state = sclp_activation_state_active;
 811         else
 812                 sclp_activation_state = sclp_activation_state_inactive;
 813         spin_unlock_irqrestore(&sclp_lock, flags);
 814         return rc;
 815 }
 816
 817 EXPORT_SYMBOL(sclp_reactivate);
 818
 819 /* Handler for external interruption used during initialization. Modify
 820  * request state to done. */
 821 static void sclp_check_handler(unsigned int ext_int_code,
 822                                unsigned int param32, unsigned long param64)
 823 {
 824         u32 finished_sccb;
 825
 826         kstat_cpu(smp_processor_id()).irqs[EXTINT_SCP]++;
 827         finished_sccb = param32 & 0xfffffff8;
 828         /* Is this the interrupt we are waiting for? */
 829         if (finished_sccb == 0)
 830                 return;
 831         if (finished_sccb != (u32) (addr_t) sclp_init_sccb)
 832                 panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
 833                       finished_sccb);
 834         spin_lock(&sclp_lock);
 835         if (sclp_running_state == sclp_running_state_running) {
 836                 sclp_init_req.status = SCLP_REQ_DONE;
 837                 sclp_running_state = sclp_running_state_idle;
 838         }
 839         spin_unlock(&sclp_lock);
 840 }
 841
 842 /* Initial init mask request timed out. Modify request state to failed. */
 843 static void
 844 sclp_check_timeout(unsigned long data)
 845 {
 846         unsigned long flags;
 847
 848         spin_lock_irqsave(&sclp_lock, flags);
 849         if (sclp_running_state == sclp_running_state_running) {
 850                 sclp_init_req.status = SCLP_REQ_FAILED;
 851                 sclp_running_state = sclp_running_state_idle;
 852         }
 853         spin_unlock_irqrestore(&sclp_lock, flags);
 854 }
 855
 856 /* Perform a check of the SCLP interface. Return zero if the interface is
 857  * available and there are no pending requests from a previous instance.
 858  * Return non-zero otherwise. */
 859 static int
 860 sclp_check_interface(void)
 861 {
 862         struct init_sccb *sccb;
 863         unsigned long flags;
 864         int retry;
 865         int rc;
 866
 867         spin_lock_irqsave(&sclp_lock, flags);
 868         /* Prepare init mask command */
 869         rc = register_external_interrupt(0x2401, sclp_check_handler);
 870         if (rc) {
 871                 spin_unlock_irqrestore(&sclp_lock, flags);
 872                 return rc;
 873         }
 874         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 875                 __sclp_make_init_req(0, 0);
 876                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 877                 rc = sclp_service_call(sclp_init_req.command, sccb);
 878                 if (rc == -EIO)
 879                         break;
 880                 sclp_init_req.status = SCLP_REQ_RUNNING;
 881                 sclp_running_state = sclp_running_state_running;
 882                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 883                                          sclp_check_timeout, 0);
 884                 spin_unlock_irqrestore(&sclp_lock, flags);
 885                 /* Enable service-signal interruption - needs to happen
 886                  * with IRQs enabled. */
 887                 service_subclass_irq_register();
 888                 /* Wait for signal from interrupt or timeout */
 889                 sclp_sync_wait();
 890                 /* Disable service-signal interruption - needs to happen
 891                  * with IRQs enabled. */
 892                 service_subclass_irq_unregister();
 893                 spin_lock_irqsave(&sclp_lock, flags);
 894                 del_timer(&sclp_request_timer);
 895                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 896                     sccb->header.response_code == 0x20) {
 897                         rc = 0;
 898                         break;
 899                 } else
 900                         rc = -EBUSY;
 901         }
 902         unregister_external_interrupt(0x2401, sclp_check_handler);
 903         spin_unlock_irqrestore(&sclp_lock, flags);
 904         return rc;
 905 }
 906
 907 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 908  * events from interfering with rebooted system. */
 909 static int
 910 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 911 {
 912         sclp_deactivate();
 913         return NOTIFY_DONE;
 914 }
 915
 916 static struct notifier_block sclp_reboot_notifier = {
 917         .notifier_call = sclp_reboot_event
 918 };
 919
 920 /*
 921  * Suspend/resume SCLP notifier implementation
 922  */
 923
 924 static void sclp_pm_event(enum sclp_pm_event sclp_pm_event, int rollback)
 925 {
 926         struct sclp_register *reg;
 927         unsigned long flags;
 928
 929         if (!rollback) {
 930                 spin_lock_irqsave(&sclp_lock, flags);
 931                 list_for_each_entry(reg, &sclp_reg_list, list)
 932                         reg->pm_event_posted = 0;
 933                 spin_unlock_irqrestore(&sclp_lock, flags);
 934         }
 935         do {
 936                 spin_lock_irqsave(&sclp_lock, flags);
 937                 list_for_each_entry(reg, &sclp_reg_list, list) {
 938                         if (rollback && reg->pm_event_posted)
 939                                 goto found;
 940                         if (!rollback && !reg->pm_event_posted)
 941                                 goto found;
 942                 }
 943                 spin_unlock_irqrestore(&sclp_lock, flags);
 944                 return;
 945 found:
 946                 spin_unlock_irqrestore(&sclp_lock, flags);
 947                 if (reg->pm_event_fn)
 948                         reg->pm_event_fn(reg, sclp_pm_event);
 949                 reg->pm_event_posted = rollback ? 0 : 1;
 950         } while (1);
 951 }
 952
 953 /*
 954  * Susend/resume callbacks for platform device
 955  */
 956
 957 static int sclp_freeze(struct device *dev)
 958 {
 959         unsigned long flags;
 960         int rc;
 961
 962         sclp_pm_event(SCLP_PM_EVENT_FREEZE, 0);
 963
 964         spin_lock_irqsave(&sclp_lock, flags);
 965         sclp_suspend_state = sclp_suspend_state_suspended;
 966         spin_unlock_irqrestore(&sclp_lock, flags);
 967
 968         /* Init supend data */
 969         memset(&sclp_suspend_req, 0, sizeof(sclp_suspend_req));
 970         sclp_suspend_req.callback = sclp_suspend_req_cb;
 971         sclp_suspend_req.status = SCLP_REQ_FILLED;
 972         init_completion(&sclp_request_queue_flushed);
 973
 974         rc = sclp_add_request(&sclp_suspend_req);
 975         if (rc == 0)
 976                 wait_for_completion(&sclp_request_queue_flushed);
 977         else if (rc != -ENODATA)
 978                 goto fail_thaw;
 979
 980         rc = sclp_deactivate();
 981         if (rc)
 982                 goto fail_thaw;
 983         return 0;
 984
 985 fail_thaw:
 986         spin_lock_irqsave(&sclp_lock, flags);
 987         sclp_suspend_state = sclp_suspend_state_running;
 988         spin_unlock_irqrestore(&sclp_lock, flags);
 989         sclp_pm_event(SCLP_PM_EVENT_THAW, 1);
 990         return rc;
 991 }
 992
 993 static int sclp_undo_suspend(enum sclp_pm_event event)
 994 {
 995         unsigned long flags;
 996         int rc;
 997
 998         rc = sclp_reactivate();
 999         if (rc)
1000                 return rc;
1001
1002         spin_lock_irqsave(&sclp_lock, flags);
1003         sclp_suspend_state = sclp_suspend_state_running;
1004         spin_unlock_irqrestore(&sclp_lock, flags);
1005
1006         sclp_pm_event(event, 0);
1007         return 0;
1008 }
1009
1010 static int sclp_thaw(struct device *dev)
1011 {
1012         return sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1013 }
1014
1015 static int sclp_restore(struct device *dev)
1016 {
1017         return sclp_undo_suspend(SCLP_PM_EVENT_RESTORE);
1018 }
1019
1020 static const struct dev_pm_ops sclp_pm_ops = {
1021         .freeze         = sclp_freeze,
1022         .thaw           = sclp_thaw,
1023         .restore        = sclp_restore,
1024 };
1025
1026 static struct platform_driver sclp_pdrv = {
1027         .driver = {
1028                 .name   = "sclp",
1029                 .owner  = THIS_MODULE,
1030                 .pm     = &sclp_pm_ops,
1031         },
1032 };
1033
1034 static struct platform_device *sclp_pdev;
1035
1036 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
1037  * otherwise. */
1038 static int
1039 sclp_init(void)
1040 {
1041         unsigned long flags;
1042         int rc = 0;
1043
1044         spin_lock_irqsave(&sclp_lock, flags);
1045         /* Check for previous or running initialization */
1046         if (sclp_init_state != sclp_init_state_uninitialized)
1047                 goto fail_unlock;
1048         sclp_init_state = sclp_init_state_initializing;
1049         /* Set up variables */
1050         INIT_LIST_HEAD(&sclp_req_queue);
1051         INIT_LIST_HEAD(&sclp_reg_list);
1052         list_add(&sclp_state_change_event.list, &sclp_reg_list);
1053         init_timer(&sclp_request_timer);
1054         /* Check interface */
1055         spin_unlock_irqrestore(&sclp_lock, flags);
1056         rc = sclp_check_interface();
1057         spin_lock_irqsave(&sclp_lock, flags);
1058         if (rc)
1059                 goto fail_init_state_uninitialized;
1060         /* Register reboot handler */
1061         rc = register_reboot_notifier(&sclp_reboot_notifier);
1062         if (rc)
1063                 goto fail_init_state_uninitialized;
1064         /* Register interrupt handler */
1065         rc = register_external_interrupt(0x2401, sclp_interrupt_handler);
1066         if (rc)
1067                 goto fail_unregister_reboot_notifier;
1068         sclp_init_state = sclp_init_state_initialized;
1069         spin_unlock_irqrestore(&sclp_lock, flags);
1070         /* Enable service-signal external interruption - needs to happen with
1071          * IRQs enabled. */
1072         service_subclass_irq_register();
1073         sclp_init_mask(1);
1074         return 0;
1075
1076 fail_unregister_reboot_notifier:
1077         unregister_reboot_notifier(&sclp_reboot_notifier);
1078 fail_init_state_uninitialized:
1079         sclp_init_state = sclp_init_state_uninitialized;
1080 fail_unlock:
1081         spin_unlock_irqrestore(&sclp_lock, flags);
1082         return rc;
1083 }
1084
1085 /*
1086  * SCLP panic notifier: If we are suspended, we thaw SCLP in order to be able
1087  * to print the panic message.
1088  */
1089 static int sclp_panic_notify(struct notifier_block *self,
1090                              unsigned long event, void *data)
1091 {
1092         if (sclp_suspend_state == sclp_suspend_state_suspended)
1093                 sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1094         return NOTIFY_OK;
1095 }
1096
1097 static struct notifier_block sclp_on_panic_nb = {
1098         .notifier_call = sclp_panic_notify,
1099         .priority = SCLP_PANIC_PRIO,
1100 };
1101
1102 static __init int sclp_initcall(void)
1103 {
1104         int rc;
1105
1106         rc = platform_driver_register(&sclp_pdrv);
1107         if (rc)
1108                 return rc;
1109         sclp_pdev = platform_device_register_simple("sclp", -1, NULL, 0);
1110         rc = IS_ERR(sclp_pdev) ? PTR_ERR(sclp_pdev) : 0;
1111         if (rc)
1112                 goto fail_platform_driver_unregister;
1113         rc = atomic_notifier_chain_register(&panic_notifier_list,
1114                                             &sclp_on_panic_nb);
1115         if (rc)
1116                 goto fail_platform_device_unregister;
1117
1118         return sclp_init();
1119
1120 fail_platform_device_unregister:
1121         platform_device_unregister(sclp_pdev);
1122 fail_platform_driver_unregister:
1123         platform_driver_unregister(&sclp_pdrv);
1124         return rc;
1125 }
1126
1127 arch_initcall(sclp_initcall);