git.oblomov.eu Git - linux-2.6/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/module.h>
  11 #include <linux/err.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/timer.h>
  15 #include <linux/reboot.h>
  16 #include <linux/jiffies.h>
  17 #include <linux/init.h>
  18 #include <linux/suspend.h>
  19 #include <linux/completion.h>
  20 #include <linux/platform_device.h>
  21 #include <asm/types.h>
  22 #include <asm/s390_ext.h>
  23
  24 #include "sclp.h"
  25
  26 #define SCLP_HEADER             "sclp: "
  27
  28 /* Structure for register_early_external_interrupt. */
  29 static ext_int_info_t ext_int_info_hwc;
  30
  31 /* Lock to protect internal data consistency. */
  32 static DEFINE_SPINLOCK(sclp_lock);
  33
  34 /* Mask of events that we can send to the sclp interface. */
  35 static sccb_mask_t sclp_receive_mask;
  36
  37 /* Mask of events that we can receive from the sclp interface. */
  38 static sccb_mask_t sclp_send_mask;
  39
  40 /* List of registered event listeners and senders. */
  41 static struct list_head sclp_reg_list;
  42
  43 /* List of queued requests. */
  44 static struct list_head sclp_req_queue;
  45
  46 /* Data for read and and init requests. */
  47 static struct sclp_req sclp_read_req;
  48 static struct sclp_req sclp_init_req;
  49 static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  50 static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  51
  52 /* Suspend request */
  53 static DECLARE_COMPLETION(sclp_request_queue_flushed);
  54
  55 static void sclp_suspend_req_cb(struct sclp_req *req, void *data)
  56 {
  57         complete(&sclp_request_queue_flushed);
  58 }
  59
  60 static struct sclp_req sclp_suspend_req;
  61
  62 /* Timer for request retries. */
  63 static struct timer_list sclp_request_timer;
  64
  65 /* Internal state: is the driver initialized? */
  66 static volatile enum sclp_init_state_t {
  67         sclp_init_state_uninitialized,
  68         sclp_init_state_initializing,
  69         sclp_init_state_initialized
  70 } sclp_init_state = sclp_init_state_uninitialized;
  71
  72 /* Internal state: is a request active at the sclp? */
  73 static volatile enum sclp_running_state_t {
  74         sclp_running_state_idle,
  75         sclp_running_state_running,
  76         sclp_running_state_reset_pending
  77 } sclp_running_state = sclp_running_state_idle;
  78
  79 /* Internal state: is a read request pending? */
  80 static volatile enum sclp_reading_state_t {
  81         sclp_reading_state_idle,
  82         sclp_reading_state_reading
  83 } sclp_reading_state = sclp_reading_state_idle;
  84
  85 /* Internal state: is the driver currently serving requests? */
  86 static volatile enum sclp_activation_state_t {
  87         sclp_activation_state_active,
  88         sclp_activation_state_deactivating,
  89         sclp_activation_state_inactive,
  90         sclp_activation_state_activating
  91 } sclp_activation_state = sclp_activation_state_active;
  92
  93 /* Internal state: is an init mask request pending? */
  94 static volatile enum sclp_mask_state_t {
  95         sclp_mask_state_idle,
  96         sclp_mask_state_initializing
  97 } sclp_mask_state = sclp_mask_state_idle;
  98
  99 /* Internal state: is the driver suspended? */
 100 static enum sclp_suspend_state_t {
 101         sclp_suspend_state_running,
 102         sclp_suspend_state_suspended,
 103 } sclp_suspend_state = sclp_suspend_state_running;
 104
 105 /* Maximum retry counts */
 106 #define SCLP_INIT_RETRY         3
 107 #define SCLP_MASK_RETRY         3
 108
 109 /* Timeout intervals in seconds.*/
 110 #define SCLP_BUSY_INTERVAL      10
 111 #define SCLP_RETRY_INTERVAL     30
 112
 113 static void sclp_process_queue(void);
 114 static void __sclp_make_read_req(void);
 115 static int sclp_init_mask(int calculate);
 116 static int sclp_init(void);
 117
 118 /* Perform service call. Return 0 on success, non-zero otherwise. */
 119 int
 120 sclp_service_call(sclp_cmdw_t command, void *sccb)
 121 {
 122         int cc;
 123
 124         asm volatile(
 125                 "       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
 126                 "       ipm     %0\n"
 127                 "       srl     %0,28"
 128                 : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
 129                 : "cc", "memory");
 130         if (cc == 3)
 131                 return -EIO;
 132         if (cc == 2)
 133                 return -EBUSY;
 134         return 0;
 135 }
 136
 137
 138 static void
 139 __sclp_queue_read_req(void)
 140 {
 141         if (sclp_reading_state == sclp_reading_state_idle) {
 142                 sclp_reading_state = sclp_reading_state_reading;
 143                 __sclp_make_read_req();
 144                 /* Add request to head of queue */
 145                 list_add(&sclp_read_req.list, &sclp_req_queue);
 146         }
 147 }
 148
 149 /* Set up request retry timer. Called while sclp_lock is locked. */
 150 static inline void
 151 __sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
 152                          unsigned long data)
 153 {
 154         del_timer(&sclp_request_timer);
 155         sclp_request_timer.function = function;
 156         sclp_request_timer.data = data;
 157         sclp_request_timer.expires = jiffies + time;
 158         add_timer(&sclp_request_timer);
 159 }
 160
 161 /* Request timeout handler. Restart the request queue. If DATA is non-zero,
 162  * force restart of running request. */
 163 static void
 164 sclp_request_timeout(unsigned long data)
 165 {
 166         unsigned long flags;
 167
 168         spin_lock_irqsave(&sclp_lock, flags);
 169         if (data) {
 170                 if (sclp_running_state == sclp_running_state_running) {
 171                         /* Break running state and queue NOP read event request
 172                          * to get a defined interface state. */
 173                         __sclp_queue_read_req();
 174                         sclp_running_state = sclp_running_state_idle;
 175                 }
 176         } else {
 177                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 178                                          sclp_request_timeout, 0);
 179         }
 180         spin_unlock_irqrestore(&sclp_lock, flags);
 181         sclp_process_queue();
 182 }
 183
 184 /* Try to start a request. Return zero if the request was successfully
 185  * started or if it will be started at a later time. Return non-zero otherwise.
 186  * Called while sclp_lock is locked. */
 187 static int
 188 __sclp_start_request(struct sclp_req *req)
 189 {
 190         int rc;
 191
 192         if (sclp_running_state != sclp_running_state_idle)
 193                 return 0;
 194         del_timer(&sclp_request_timer);
 195         rc = sclp_service_call(req->command, req->sccb);
 196         req->start_count++;
 197
 198         if (rc == 0) {
 199                 /* Sucessfully started request */
 200                 req->status = SCLP_REQ_RUNNING;
 201                 sclp_running_state = sclp_running_state_running;
 202                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 203                                          sclp_request_timeout, 1);
 204                 return 0;
 205         } else if (rc == -EBUSY) {
 206                 /* Try again later */
 207                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 208                                          sclp_request_timeout, 0);
 209                 return 0;
 210         }
 211         /* Request failed */
 212         req->status = SCLP_REQ_FAILED;
 213         return rc;
 214 }
 215
 216 /* Try to start queued requests. */
 217 static void
 218 sclp_process_queue(void)
 219 {
 220         struct sclp_req *req;
 221         int rc;
 222         unsigned long flags;
 223
 224         spin_lock_irqsave(&sclp_lock, flags);
 225         if (sclp_running_state != sclp_running_state_idle) {
 226                 spin_unlock_irqrestore(&sclp_lock, flags);
 227                 return;
 228         }
 229         del_timer(&sclp_request_timer);
 230         while (!list_empty(&sclp_req_queue)) {
 231                 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
 232                 if (!req->sccb)
 233                         goto do_post;
 234                 rc = __sclp_start_request(req);
 235                 if (rc == 0)
 236                         break;
 237                 /* Request failed */
 238                 if (req->start_count > 1) {
 239                         /* Cannot abort already submitted request - could still
 240                          * be active at the SCLP */
 241                         __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 242                                                  sclp_request_timeout, 0);
 243                         break;
 244                 }
 245 do_post:
 246                 /* Post-processing for aborted request */
 247                 list_del(&req->list);
 248                 if (req->callback) {
 249                         spin_unlock_irqrestore(&sclp_lock, flags);
 250                         req->callback(req, req->callback_data);
 251                         spin_lock_irqsave(&sclp_lock, flags);
 252                 }
 253         }
 254         spin_unlock_irqrestore(&sclp_lock, flags);
 255 }
 256
 257 static int __sclp_can_add_request(struct sclp_req *req)
 258 {
 259         if (req == &sclp_suspend_req || req == &sclp_init_req)
 260                 return 1;
 261         if (sclp_suspend_state != sclp_suspend_state_running)
 262                 return 0;
 263         if (sclp_init_state != sclp_init_state_initialized)
 264                 return 0;
 265         if (sclp_activation_state != sclp_activation_state_active)
 266                 return 0;
 267         return 1;
 268 }
 269
 270 /* Queue a new request. Return zero on success, non-zero otherwise. */
 271 int
 272 sclp_add_request(struct sclp_req *req)
 273 {
 274         unsigned long flags;
 275         int rc;
 276
 277         spin_lock_irqsave(&sclp_lock, flags);
 278         if (!__sclp_can_add_request(req)) {
 279                 spin_unlock_irqrestore(&sclp_lock, flags);
 280                 return -EIO;
 281         }
 282         req->status = SCLP_REQ_QUEUED;
 283         req->start_count = 0;
 284         list_add_tail(&req->list, &sclp_req_queue);
 285         rc = 0;
 286         /* Start if request is first in list */
 287         if (sclp_running_state == sclp_running_state_idle &&
 288             req->list.prev == &sclp_req_queue) {
 289                 if (!req->sccb) {
 290                         list_del(&req->list);
 291                         rc = -ENODATA;
 292                         goto out;
 293                 }
 294                 rc = __sclp_start_request(req);
 295                 if (rc)
 296                         list_del(&req->list);
 297         }
 298 out:
 299         spin_unlock_irqrestore(&sclp_lock, flags);
 300         return rc;
 301 }
 302
 303 EXPORT_SYMBOL(sclp_add_request);
 304
 305 /* Dispatch events found in request buffer to registered listeners. Return 0
 306  * if all events were dispatched, non-zero otherwise. */
 307 static int
 308 sclp_dispatch_evbufs(struct sccb_header *sccb)
 309 {
 310         unsigned long flags;
 311         struct evbuf_header *evbuf;
 312         struct list_head *l;
 313         struct sclp_register *reg;
 314         int offset;
 315         int rc;
 316
 317         spin_lock_irqsave(&sclp_lock, flags);
 318         rc = 0;
 319         for (offset = sizeof(struct sccb_header); offset < sccb->length;
 320              offset += evbuf->length) {
 321                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 322                 /* Check for malformed hardware response */
 323                 if (evbuf->length == 0)
 324                         break;
 325                 /* Search for event handler */
 326                 reg = NULL;
 327                 list_for_each(l, &sclp_reg_list) {
 328                         reg = list_entry(l, struct sclp_register, list);
 329                         if (reg->receive_mask & (1 << (32 - evbuf->type)))
 330                                 break;
 331                         else
 332                                 reg = NULL;
 333                 }
 334                 if (reg && reg->receiver_fn) {
 335                         spin_unlock_irqrestore(&sclp_lock, flags);
 336                         reg->receiver_fn(evbuf);
 337                         spin_lock_irqsave(&sclp_lock, flags);
 338                 } else if (reg == NULL)
 339                         rc = -ENOSYS;
 340         }
 341         spin_unlock_irqrestore(&sclp_lock, flags);
 342         return rc;
 343 }
 344
 345 /* Read event data request callback. */
 346 static void
 347 sclp_read_cb(struct sclp_req *req, void *data)
 348 {
 349         unsigned long flags;
 350         struct sccb_header *sccb;
 351
 352         sccb = (struct sccb_header *) req->sccb;
 353         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 354             sccb->response_code == 0x220))
 355                 sclp_dispatch_evbufs(sccb);
 356         spin_lock_irqsave(&sclp_lock, flags);
 357         sclp_reading_state = sclp_reading_state_idle;
 358         spin_unlock_irqrestore(&sclp_lock, flags);
 359 }
 360
 361 /* Prepare read event data request. Called while sclp_lock is locked. */
 362 static void __sclp_make_read_req(void)
 363 {
 364         struct sccb_header *sccb;
 365
 366         sccb = (struct sccb_header *) sclp_read_sccb;
 367         clear_page(sccb);
 368         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 369         sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
 370         sclp_read_req.status = SCLP_REQ_QUEUED;
 371         sclp_read_req.start_count = 0;
 372         sclp_read_req.callback = sclp_read_cb;
 373         sclp_read_req.sccb = sccb;
 374         sccb->length = PAGE_SIZE;
 375         sccb->function_code = 0;
 376         sccb->control_mask[2] = 0x80;
 377 }
 378
 379 /* Search request list for request with matching sccb. Return request if found,
 380  * NULL otherwise. Called while sclp_lock is locked. */
 381 static inline struct sclp_req *
 382 __sclp_find_req(u32 sccb)
 383 {
 384         struct list_head *l;
 385         struct sclp_req *req;
 386
 387         list_for_each(l, &sclp_req_queue) {
 388                 req = list_entry(l, struct sclp_req, list);
 389                 if (sccb == (u32) (addr_t) req->sccb)
 390                                 return req;
 391         }
 392         return NULL;
 393 }
 394
 395 /* Handler for external interruption. Perform request post-processing.
 396  * Prepare read event data request if necessary. Start processing of next
 397  * request on queue. */
 398 static void
 399 sclp_interrupt_handler(__u16 code)
 400 {
 401         struct sclp_req *req;
 402         u32 finished_sccb;
 403         u32 evbuf_pending;
 404
 405         spin_lock(&sclp_lock);
 406         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 407         evbuf_pending = S390_lowcore.ext_params & 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         __raw_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
 823 sclp_check_handler(__u16 code)
 824 {
 825         u32 finished_sccb;
 826
 827         finished_sccb = S390_lowcore.ext_params & 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_early_external_interrupt(0x2401, sclp_check_handler,
 870                                                &ext_int_info_hwc);
 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_early_external_interrupt(0x2401, sclp_check_handler,
 904                                             &ext_int_info_hwc);
 905         spin_unlock_irqrestore(&sclp_lock, flags);
 906         return rc;
 907 }
 908
 909 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 910  * events from interfering with rebooted system. */
 911 static int
 912 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 913 {
 914         sclp_deactivate();
 915         return NOTIFY_DONE;
 916 }
 917
 918 static struct notifier_block sclp_reboot_notifier = {
 919         .notifier_call = sclp_reboot_event
 920 };
 921
 922 /*
 923  * Suspend/resume SCLP notifier implementation
 924  */
 925
 926 static void sclp_pm_event(enum sclp_pm_event sclp_pm_event, int rollback)
 927 {
 928         struct sclp_register *reg;
 929         unsigned long flags;
 930
 931         if (!rollback) {
 932                 spin_lock_irqsave(&sclp_lock, flags);
 933                 list_for_each_entry(reg, &sclp_reg_list, list)
 934                         reg->pm_event_posted = 0;
 935                 spin_unlock_irqrestore(&sclp_lock, flags);
 936         }
 937         do {
 938                 spin_lock_irqsave(&sclp_lock, flags);
 939                 list_for_each_entry(reg, &sclp_reg_list, list) {
 940                         if (rollback && reg->pm_event_posted)
 941                                 goto found;
 942                         if (!rollback && !reg->pm_event_posted)
 943                                 goto found;
 944                 }
 945                 spin_unlock_irqrestore(&sclp_lock, flags);
 946                 return;
 947 found:
 948                 spin_unlock_irqrestore(&sclp_lock, flags);
 949                 if (reg->pm_event_fn)
 950                         reg->pm_event_fn(reg, sclp_pm_event);
 951                 reg->pm_event_posted = rollback ? 0 : 1;
 952         } while (1);
 953 }
 954
 955 /*
 956  * Susend/resume callbacks for platform device
 957  */
 958
 959 static int sclp_freeze(struct device *dev)
 960 {
 961         unsigned long flags;
 962         int rc;
 963
 964         sclp_pm_event(SCLP_PM_EVENT_FREEZE, 0);
 965
 966         spin_lock_irqsave(&sclp_lock, flags);
 967         sclp_suspend_state = sclp_suspend_state_suspended;
 968         spin_unlock_irqrestore(&sclp_lock, flags);
 969
 970         /* Init supend data */
 971         memset(&sclp_suspend_req, 0, sizeof(sclp_suspend_req));
 972         sclp_suspend_req.callback = sclp_suspend_req_cb;
 973         sclp_suspend_req.status = SCLP_REQ_FILLED;
 974         init_completion(&sclp_request_queue_flushed);
 975
 976         rc = sclp_add_request(&sclp_suspend_req);
 977         if (rc == 0)
 978                 wait_for_completion(&sclp_request_queue_flushed);
 979         else if (rc != -ENODATA)
 980                 goto fail_thaw;
 981
 982         rc = sclp_deactivate();
 983         if (rc)
 984                 goto fail_thaw;
 985         return 0;
 986
 987 fail_thaw:
 988         spin_lock_irqsave(&sclp_lock, flags);
 989         sclp_suspend_state = sclp_suspend_state_running;
 990         spin_unlock_irqrestore(&sclp_lock, flags);
 991         sclp_pm_event(SCLP_PM_EVENT_THAW, 1);
 992         return rc;
 993 }
 994
 995 static int sclp_undo_suspend(enum sclp_pm_event event)
 996 {
 997         unsigned long flags;
 998         int rc;
 999
1000         rc = sclp_reactivate();
1001         if (rc)
1002                 return rc;
1003
1004         spin_lock_irqsave(&sclp_lock, flags);
1005         sclp_suspend_state = sclp_suspend_state_running;
1006         spin_unlock_irqrestore(&sclp_lock, flags);
1007
1008         sclp_pm_event(event, 0);
1009         return 0;
1010 }
1011
1012 static int sclp_thaw(struct device *dev)
1013 {
1014         return sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1015 }
1016
1017 static int sclp_restore(struct device *dev)
1018 {
1019         return sclp_undo_suspend(SCLP_PM_EVENT_RESTORE);
1020 }
1021
1022 static struct dev_pm_ops sclp_pm_ops = {
1023         .freeze         = sclp_freeze,
1024         .thaw           = sclp_thaw,
1025         .restore        = sclp_restore,
1026 };
1027
1028 static struct platform_driver sclp_pdrv = {
1029         .driver = {
1030                 .name   = "sclp",
1031                 .owner  = THIS_MODULE,
1032                 .pm     = &sclp_pm_ops,
1033         },
1034 };
1035
1036 static struct platform_device *sclp_pdev;
1037
1038 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
1039  * otherwise. */
1040 static int
1041 sclp_init(void)
1042 {
1043         unsigned long flags;
1044         int rc = 0;
1045
1046         spin_lock_irqsave(&sclp_lock, flags);
1047         /* Check for previous or running initialization */
1048         if (sclp_init_state != sclp_init_state_uninitialized)
1049                 goto fail_unlock;
1050         sclp_init_state = sclp_init_state_initializing;
1051         /* Set up variables */
1052         INIT_LIST_HEAD(&sclp_req_queue);
1053         INIT_LIST_HEAD(&sclp_reg_list);
1054         list_add(&sclp_state_change_event.list, &sclp_reg_list);
1055         init_timer(&sclp_request_timer);
1056         /* Check interface */
1057         spin_unlock_irqrestore(&sclp_lock, flags);
1058         rc = sclp_check_interface();
1059         spin_lock_irqsave(&sclp_lock, flags);
1060         if (rc)
1061                 goto fail_init_state_uninitialized;
1062         /* Register reboot handler */
1063         rc = register_reboot_notifier(&sclp_reboot_notifier);
1064         if (rc)
1065                 goto fail_init_state_uninitialized;
1066         /* Register interrupt handler */
1067         rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler,
1068                                                &ext_int_info_hwc);
1069         if (rc)
1070                 goto fail_unregister_reboot_notifier;
1071         sclp_init_state = sclp_init_state_initialized;
1072         spin_unlock_irqrestore(&sclp_lock, flags);
1073         /* Enable service-signal external interruption - needs to happen with
1074          * IRQs enabled. */
1075         ctl_set_bit(0, 9);
1076         sclp_init_mask(1);
1077         return 0;
1078
1079 fail_unregister_reboot_notifier:
1080         unregister_reboot_notifier(&sclp_reboot_notifier);
1081 fail_init_state_uninitialized:
1082         sclp_init_state = sclp_init_state_uninitialized;
1083 fail_unlock:
1084         spin_unlock_irqrestore(&sclp_lock, flags);
1085         return rc;
1086 }
1087
1088 /*
1089  * SCLP panic notifier: If we are suspended, we thaw SCLP in order to be able
1090  * to print the panic message.
1091  */
1092 static int sclp_panic_notify(struct notifier_block *self,
1093                              unsigned long event, void *data)
1094 {
1095         if (sclp_suspend_state == sclp_suspend_state_suspended)
1096                 sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1097         return NOTIFY_OK;
1098 }
1099
1100 static struct notifier_block sclp_on_panic_nb = {
1101         .notifier_call = sclp_panic_notify,
1102         .priority = SCLP_PANIC_PRIO,
1103 };
1104
1105 static __init int sclp_initcall(void)
1106 {
1107         int rc;
1108
1109         rc = platform_driver_register(&sclp_pdrv);
1110         if (rc)
1111                 return rc;
1112         sclp_pdev = platform_device_register_simple("sclp", -1, NULL, 0);
1113         rc = IS_ERR(sclp_pdev) ? PTR_ERR(sclp_pdev) : 0;
1114         if (rc)
1115                 goto fail_platform_driver_unregister;
1116         rc = atomic_notifier_chain_register(&panic_notifier_list,
1117                                             &sclp_on_panic_nb);
1118         if (rc)
1119                 goto fail_platform_device_unregister;
1120
1121         return sclp_init();
1122
1123 fail_platform_device_unregister:
1124         platform_device_unregister(sclp_pdev);
1125 fail_platform_driver_unregister:
1126         platform_driver_unregister(&sclp_pdrv);
1127         return rc;
1128 }
1129
1130 arch_initcall(sclp_initcall);