git.oblomov.eu Git - linux-2.6/blob - drivers/s390/char/sclp.c

   1 /*
   2  *  drivers/s390/char/sclp.c
   3  *     core function to access sclp interface
   4  *
   5  *  S390 version
   6  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
   7  *    Author(s): Martin Peschke <mpeschke@de.ibm.com>
   8  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
   9  */
  10
  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 <asm/types.h>
  19 #include <asm/s390_ext.h>
  20
  21 #include "sclp.h"
  22
  23 #define SCLP_HEADER             "sclp: "
  24
  25 /* Structure for register_early_external_interrupt. */
  26 static ext_int_info_t ext_int_info_hwc;
  27
  28 /* Lock to protect internal data consistency. */
  29 static DEFINE_SPINLOCK(sclp_lock);
  30
  31 /* Mask of events that we can receive from the sclp interface. */
  32 static sccb_mask_t sclp_receive_mask;
  33
  34 /* Mask of events that we can send to the sclp interface. */
  35 static sccb_mask_t sclp_send_mask;
  36
  37 /* List of registered event listeners and senders. */
  38 static struct list_head sclp_reg_list;
  39
  40 /* List of queued requests. */
  41 static struct list_head sclp_req_queue;
  42
  43 /* Data for read and and init requests. */
  44 static struct sclp_req sclp_read_req;
  45 static struct sclp_req sclp_init_req;
  46 static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  47 static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  48
  49 /* Timer for request retries. */
  50 static struct timer_list sclp_request_timer;
  51
  52 /* Internal state: is the driver initialized? */
  53 static volatile enum sclp_init_state_t {
  54         sclp_init_state_uninitialized,
  55         sclp_init_state_initializing,
  56         sclp_init_state_initialized
  57 } sclp_init_state = sclp_init_state_uninitialized;
  58
  59 /* Internal state: is a request active at the sclp? */
  60 static volatile enum sclp_running_state_t {
  61         sclp_running_state_idle,
  62         sclp_running_state_running
  63 } sclp_running_state = sclp_running_state_idle;
  64
  65 /* Internal state: is a read request pending? */
  66 static volatile enum sclp_reading_state_t {
  67         sclp_reading_state_idle,
  68         sclp_reading_state_reading
  69 } sclp_reading_state = sclp_reading_state_idle;
  70
  71 /* Internal state: is the driver currently serving requests? */
  72 static volatile enum sclp_activation_state_t {
  73         sclp_activation_state_active,
  74         sclp_activation_state_deactivating,
  75         sclp_activation_state_inactive,
  76         sclp_activation_state_activating
  77 } sclp_activation_state = sclp_activation_state_active;
  78
  79 /* Internal state: is an init mask request pending? */
  80 static volatile enum sclp_mask_state_t {
  81         sclp_mask_state_idle,
  82         sclp_mask_state_initializing
  83 } sclp_mask_state = sclp_mask_state_idle;
  84
  85 /* Maximum retry counts */
  86 #define SCLP_INIT_RETRY         3
  87 #define SCLP_MASK_RETRY         3
  88
  89 /* Timeout intervals in seconds.*/
  90 #define SCLP_BUSY_INTERVAL      10
  91 #define SCLP_RETRY_INTERVAL     15
  92
  93 static void sclp_process_queue(void);
  94 static int sclp_init_mask(int calculate);
  95 static int sclp_init(void);
  96
  97 /* Perform service call. Return 0 on success, non-zero otherwise. */
  98 static int
  99 service_call(sclp_cmdw_t command, void *sccb)
 100 {
 101         int cc;
 102
 103         __asm__ __volatile__(
 104                 "   .insn rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
 105                 "   ipm   %0\n"
 106                 "   srl   %0,28"
 107                 : "=&d" (cc)
 108                 : "d" (command), "a" (__pa(sccb))
 109                 : "cc", "memory" );
 110         if (cc == 3)
 111                 return -EIO;
 112         if (cc == 2)
 113                 return -EBUSY;
 114         return 0;
 115 }
 116
 117 /* Request timeout handler. Restart the request queue. If DATA is non-zero,
 118  * force restart of running request. */
 119 static void
 120 sclp_request_timeout(unsigned long data)
 121 {
 122         unsigned long flags;
 123
 124         if (data) {
 125                 spin_lock_irqsave(&sclp_lock, flags);
 126                 sclp_running_state = sclp_running_state_idle;
 127                 spin_unlock_irqrestore(&sclp_lock, flags);
 128         }
 129         sclp_process_queue();
 130 }
 131
 132 /* Set up request retry timer. Called while sclp_lock is locked. */
 133 static inline void
 134 __sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
 135                          unsigned long data)
 136 {
 137         del_timer(&sclp_request_timer);
 138         sclp_request_timer.function = function;
 139         sclp_request_timer.data = data;
 140         sclp_request_timer.expires = jiffies + time;
 141         add_timer(&sclp_request_timer);
 142 }
 143
 144 /* Try to start a request. Return zero if the request was successfully
 145  * started or if it will be started at a later time. Return non-zero otherwise.
 146  * Called while sclp_lock is locked. */
 147 static int
 148 __sclp_start_request(struct sclp_req *req)
 149 {
 150         int rc;
 151
 152         if (sclp_running_state != sclp_running_state_idle)
 153                 return 0;
 154         del_timer(&sclp_request_timer);
 155         rc = service_call(req->command, req->sccb);
 156         req->start_count++;
 157
 158         if (rc == 0) {
 159                 /* Sucessfully started request */
 160                 req->status = SCLP_REQ_RUNNING;
 161                 sclp_running_state = sclp_running_state_running;
 162                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 163                                          sclp_request_timeout, 1);
 164                 return 0;
 165         } else if (rc == -EBUSY) {
 166                 /* Try again later */
 167                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 168                                          sclp_request_timeout, 0);
 169                 return 0;
 170         }
 171         /* Request failed */
 172         req->status = SCLP_REQ_FAILED;
 173         return rc;
 174 }
 175
 176 /* Try to start queued requests. */
 177 static void
 178 sclp_process_queue(void)
 179 {
 180         struct sclp_req *req;
 181         int rc;
 182         unsigned long flags;
 183
 184         spin_lock_irqsave(&sclp_lock, flags);
 185         if (sclp_running_state != sclp_running_state_idle) {
 186                 spin_unlock_irqrestore(&sclp_lock, flags);
 187                 return;
 188         }
 189         del_timer(&sclp_request_timer);
 190         while (!list_empty(&sclp_req_queue)) {
 191                 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
 192                 rc = __sclp_start_request(req);
 193                 if (rc == 0)
 194                         break;
 195                 /* Request failed. */
 196                 list_del(&req->list);
 197                 if (req->callback) {
 198                         spin_unlock_irqrestore(&sclp_lock, flags);
 199                         req->callback(req, req->callback_data);
 200                         spin_lock_irqsave(&sclp_lock, flags);
 201                 }
 202         }
 203         spin_unlock_irqrestore(&sclp_lock, flags);
 204 }
 205
 206 /* Queue a new request. Return zero on success, non-zero otherwise. */
 207 int
 208 sclp_add_request(struct sclp_req *req)
 209 {
 210         unsigned long flags;
 211         int rc;
 212
 213         spin_lock_irqsave(&sclp_lock, flags);
 214         if ((sclp_init_state != sclp_init_state_initialized ||
 215              sclp_activation_state != sclp_activation_state_active) &&
 216             req != &sclp_init_req) {
 217                 spin_unlock_irqrestore(&sclp_lock, flags);
 218                 return -EIO;
 219         }
 220         req->status = SCLP_REQ_QUEUED;
 221         req->start_count = 0;
 222         list_add_tail(&req->list, &sclp_req_queue);
 223         rc = 0;
 224         /* Start if request is first in list */
 225         if (req->list.prev == &sclp_req_queue) {
 226                 rc = __sclp_start_request(req);
 227                 if (rc)
 228                         list_del(&req->list);
 229         }
 230         spin_unlock_irqrestore(&sclp_lock, flags);
 231         return rc;
 232 }
 233
 234 EXPORT_SYMBOL(sclp_add_request);
 235
 236 /* Dispatch events found in request buffer to registered listeners. Return 0
 237  * if all events were dispatched, non-zero otherwise. */
 238 static int
 239 sclp_dispatch_evbufs(struct sccb_header *sccb)
 240 {
 241         unsigned long flags;
 242         struct evbuf_header *evbuf;
 243         struct list_head *l;
 244         struct sclp_register *reg;
 245         int offset;
 246         int rc;
 247
 248         spin_lock_irqsave(&sclp_lock, flags);
 249         rc = 0;
 250         for (offset = sizeof(struct sccb_header); offset < sccb->length;
 251              offset += evbuf->length) {
 252                 /* Search for event handler */
 253                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 254                 reg = NULL;
 255                 list_for_each(l, &sclp_reg_list) {
 256                         reg = list_entry(l, struct sclp_register, list);
 257                         if (reg->receive_mask & (1 << (32 - evbuf->type)))
 258                                 break;
 259                         else
 260                                 reg = NULL;
 261                 }
 262                 if (reg && reg->receiver_fn) {
 263                         spin_unlock_irqrestore(&sclp_lock, flags);
 264                         reg->receiver_fn(evbuf);
 265                         spin_lock_irqsave(&sclp_lock, flags);
 266                 } else if (reg == NULL)
 267                         rc = -ENOSYS;
 268         }
 269         spin_unlock_irqrestore(&sclp_lock, flags);
 270         return rc;
 271 }
 272
 273 /* Read event data request callback. */
 274 static void
 275 sclp_read_cb(struct sclp_req *req, void *data)
 276 {
 277         unsigned long flags;
 278         struct sccb_header *sccb;
 279
 280         sccb = (struct sccb_header *) req->sccb;
 281         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 282             sccb->response_code == 0x220))
 283                 sclp_dispatch_evbufs(sccb);
 284         spin_lock_irqsave(&sclp_lock, flags);
 285         sclp_reading_state = sclp_reading_state_idle;
 286         spin_unlock_irqrestore(&sclp_lock, flags);
 287 }
 288
 289 /* Prepare read event data request. Called while sclp_lock is locked. */
 290 static inline void
 291 __sclp_make_read_req(void)
 292 {
 293         struct sccb_header *sccb;
 294
 295         sccb = (struct sccb_header *) sclp_read_sccb;
 296         clear_page(sccb);
 297         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 298         sclp_read_req.command = SCLP_CMDW_READDATA;
 299         sclp_read_req.status = SCLP_REQ_QUEUED;
 300         sclp_read_req.start_count = 0;
 301         sclp_read_req.callback = sclp_read_cb;
 302         sclp_read_req.sccb = sccb;
 303         sccb->length = PAGE_SIZE;
 304         sccb->function_code = 0;
 305         sccb->control_mask[2] = 0x80;
 306 }
 307
 308 /* Search request list for request with matching sccb. Return request if found,
 309  * NULL otherwise. Called while sclp_lock is locked. */
 310 static inline struct sclp_req *
 311 __sclp_find_req(u32 sccb)
 312 {
 313         struct list_head *l;
 314         struct sclp_req *req;
 315
 316         list_for_each(l, &sclp_req_queue) {
 317                 req = list_entry(l, struct sclp_req, list);
 318                 if (sccb == (u32) (addr_t) req->sccb)
 319                                 return req;
 320         }
 321         return NULL;
 322 }
 323
 324 /* Handler for external interruption. Perform request post-processing.
 325  * Prepare read event data request if necessary. Start processing of next
 326  * request on queue. */
 327 static void
 328 sclp_interrupt_handler(struct pt_regs *regs, __u16 code)
 329 {
 330         struct sclp_req *req;
 331         u32 finished_sccb;
 332         u32 evbuf_pending;
 333
 334         spin_lock(&sclp_lock);
 335         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 336         evbuf_pending = S390_lowcore.ext_params & 0x3;
 337         if (finished_sccb) {
 338                 req = __sclp_find_req(finished_sccb);
 339                 if (req) {
 340                         /* Request post-processing */
 341                         list_del(&req->list);
 342                         req->status = SCLP_REQ_DONE;
 343                         if (req->callback) {
 344                                 spin_unlock(&sclp_lock);
 345                                 req->callback(req, req->callback_data);
 346                                 spin_lock(&sclp_lock);
 347                         }
 348                 }
 349                 sclp_running_state = sclp_running_state_idle;
 350         }
 351         if (evbuf_pending && sclp_receive_mask != 0 &&
 352             sclp_reading_state == sclp_reading_state_idle &&
 353             sclp_activation_state == sclp_activation_state_active ) {
 354                 sclp_reading_state = sclp_reading_state_reading;
 355                 __sclp_make_read_req();
 356                 /* Add request to head of queue */
 357                 list_add(&sclp_read_req.list, &sclp_req_queue);
 358         }
 359         spin_unlock(&sclp_lock);
 360         sclp_process_queue();
 361 }
 362
 363 /* Return current Time-Of-Day clock. */
 364 static inline u64
 365 sclp_get_clock(void)
 366 {
 367         u64 result;
 368
 369         asm volatile ("STCK 0(%1)" : "=m" (result) : "a" (&(result)) : "cc");
 370         return result;
 371 }
 372
 373 /* Convert interval in jiffies to TOD ticks. */
 374 static inline u64
 375 sclp_tod_from_jiffies(unsigned long jiffies)
 376 {
 377         return (u64) (jiffies / HZ) << 32;
 378 }
 379
 380 /* Wait until a currently running request finished. Note: while this function
 381  * is running, no timers are served on the calling CPU. */
 382 void
 383 sclp_sync_wait(void)
 384 {
 385         unsigned long psw_mask;
 386         unsigned long flags;
 387         unsigned long cr0, cr0_sync;
 388         u64 timeout;
 389
 390         /* We'll be disabling timer interrupts, so we need a custom timeout
 391          * mechanism */
 392         timeout = 0;
 393         if (timer_pending(&sclp_request_timer)) {
 394                 /* Get timeout TOD value */
 395                 timeout = sclp_get_clock() +
 396                           sclp_tod_from_jiffies(sclp_request_timer.expires -
 397                                                 jiffies);
 398         }
 399         local_irq_save(flags);
 400         /* Prevent bottom half from executing once we force interrupts open */
 401         local_bh_disable();
 402         /* Enable service-signal interruption, disable timer interrupts */
 403         trace_hardirqs_on();
 404         __ctl_store(cr0, 0, 0);
 405         cr0_sync = cr0;
 406         cr0_sync |= 0x00000200;
 407         cr0_sync &= 0xFFFFF3AC;
 408         __ctl_load(cr0_sync, 0, 0);
 409         asm volatile ("STOSM 0(%1),0x01"
 410                       : "=m" (psw_mask) : "a" (&psw_mask) : "memory");
 411         /* Loop until driver state indicates finished request */
 412         while (sclp_running_state != sclp_running_state_idle) {
 413                 /* Check for expired request timer */
 414                 if (timer_pending(&sclp_request_timer) &&
 415                     sclp_get_clock() > timeout &&
 416                     del_timer(&sclp_request_timer))
 417                         sclp_request_timer.function(sclp_request_timer.data);
 418                 barrier();
 419                 cpu_relax();
 420         }
 421         local_irq_disable();
 422         __ctl_load(cr0, 0, 0);
 423         _local_bh_enable();
 424         local_irq_restore(flags);
 425 }
 426
 427 EXPORT_SYMBOL(sclp_sync_wait);
 428
 429 /* Dispatch changes in send and receive mask to registered listeners. */
 430 static inline void
 431 sclp_dispatch_state_change(void)
 432 {
 433         struct list_head *l;
 434         struct sclp_register *reg;
 435         unsigned long flags;
 436         sccb_mask_t receive_mask;
 437         sccb_mask_t send_mask;
 438
 439         do {
 440                 spin_lock_irqsave(&sclp_lock, flags);
 441                 reg = NULL;
 442                 list_for_each(l, &sclp_reg_list) {
 443                         reg = list_entry(l, struct sclp_register, list);
 444                         receive_mask = reg->receive_mask & sclp_receive_mask;
 445                         send_mask = reg->send_mask & sclp_send_mask;
 446                         if (reg->sclp_receive_mask != receive_mask ||
 447                             reg->sclp_send_mask != send_mask) {
 448                                 reg->sclp_receive_mask = receive_mask;
 449                                 reg->sclp_send_mask = send_mask;
 450                                 break;
 451                         } else
 452                                 reg = NULL;
 453                 }
 454                 spin_unlock_irqrestore(&sclp_lock, flags);
 455                 if (reg && reg->state_change_fn)
 456                         reg->state_change_fn(reg);
 457         } while (reg);
 458 }
 459
 460 struct sclp_statechangebuf {
 461         struct evbuf_header     header;
 462         u8              validity_sclp_active_facility_mask : 1;
 463         u8              validity_sclp_receive_mask : 1;
 464         u8              validity_sclp_send_mask : 1;
 465         u8              validity_read_data_function_mask : 1;
 466         u16             _zeros : 12;
 467         u16             mask_length;
 468         u64             sclp_active_facility_mask;
 469         sccb_mask_t     sclp_receive_mask;
 470         sccb_mask_t     sclp_send_mask;
 471         u32             read_data_function_mask;
 472 } __attribute__((packed));
 473
 474
 475 /* State change event callback. Inform listeners of changes. */
 476 static void
 477 sclp_state_change_cb(struct evbuf_header *evbuf)
 478 {
 479         unsigned long flags;
 480         struct sclp_statechangebuf *scbuf;
 481
 482         scbuf = (struct sclp_statechangebuf *) evbuf;
 483         if (scbuf->mask_length != sizeof(sccb_mask_t))
 484                 return;
 485         spin_lock_irqsave(&sclp_lock, flags);
 486         if (scbuf->validity_sclp_receive_mask)
 487                 sclp_receive_mask = scbuf->sclp_receive_mask;
 488         if (scbuf->validity_sclp_send_mask)
 489                 sclp_send_mask = scbuf->sclp_send_mask;
 490         spin_unlock_irqrestore(&sclp_lock, flags);
 491         sclp_dispatch_state_change();
 492 }
 493
 494 static struct sclp_register sclp_state_change_event = {
 495         .receive_mask = EvTyp_StateChange_Mask,
 496         .receiver_fn = sclp_state_change_cb
 497 };
 498
 499 /* Calculate receive and send mask of currently registered listeners.
 500  * Called while sclp_lock is locked. */
 501 static inline void
 502 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 503 {
 504         struct list_head *l;
 505         struct sclp_register *t;
 506
 507         *receive_mask = 0;
 508         *send_mask = 0;
 509         list_for_each(l, &sclp_reg_list) {
 510                 t = list_entry(l, struct sclp_register, list);
 511                 *receive_mask |= t->receive_mask;
 512                 *send_mask |= t->send_mask;
 513         }
 514 }
 515
 516 /* Register event listener. Return 0 on success, non-zero otherwise. */
 517 int
 518 sclp_register(struct sclp_register *reg)
 519 {
 520         unsigned long flags;
 521         sccb_mask_t receive_mask;
 522         sccb_mask_t send_mask;
 523         int rc;
 524
 525         rc = sclp_init();
 526         if (rc)
 527                 return rc;
 528         spin_lock_irqsave(&sclp_lock, flags);
 529         /* Check event mask for collisions */
 530         __sclp_get_mask(&receive_mask, &send_mask);
 531         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 532                 spin_unlock_irqrestore(&sclp_lock, flags);
 533                 return -EBUSY;
 534         }
 535         /* Trigger initial state change callback */
 536         reg->sclp_receive_mask = 0;
 537         reg->sclp_send_mask = 0;
 538         list_add(&reg->list, &sclp_reg_list);
 539         spin_unlock_irqrestore(&sclp_lock, flags);
 540         rc = sclp_init_mask(1);
 541         if (rc) {
 542                 spin_lock_irqsave(&sclp_lock, flags);
 543                 list_del(&reg->list);
 544                 spin_unlock_irqrestore(&sclp_lock, flags);
 545         }
 546         return rc;
 547 }
 548
 549 EXPORT_SYMBOL(sclp_register);
 550
 551 /* Unregister event listener. */
 552 void
 553 sclp_unregister(struct sclp_register *reg)
 554 {
 555         unsigned long flags;
 556
 557         spin_lock_irqsave(&sclp_lock, flags);
 558         list_del(&reg->list);
 559         spin_unlock_irqrestore(&sclp_lock, flags);
 560         sclp_init_mask(1);
 561 }
 562
 563 EXPORT_SYMBOL(sclp_unregister);
 564
 565 /* Remove event buffers which are marked processed. Return the number of
 566  * remaining event buffers. */
 567 int
 568 sclp_remove_processed(struct sccb_header *sccb)
 569 {
 570         struct evbuf_header *evbuf;
 571         int unprocessed;
 572         u16 remaining;
 573
 574         evbuf = (struct evbuf_header *) (sccb + 1);
 575         unprocessed = 0;
 576         remaining = sccb->length - sizeof(struct sccb_header);
 577         while (remaining > 0) {
 578                 remaining -= evbuf->length;
 579                 if (evbuf->flags & 0x80) {
 580                         sccb->length -= evbuf->length;
 581                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 582                                remaining);
 583                 } else {
 584                         unprocessed++;
 585                         evbuf = (struct evbuf_header *)
 586                                         ((addr_t) evbuf + evbuf->length);
 587                 }
 588         }
 589         return unprocessed;
 590 }
 591
 592 EXPORT_SYMBOL(sclp_remove_processed);
 593
 594 struct init_sccb {
 595         struct sccb_header header;
 596         u16 _reserved;
 597         u16 mask_length;
 598         sccb_mask_t receive_mask;
 599         sccb_mask_t send_mask;
 600         sccb_mask_t sclp_send_mask;
 601         sccb_mask_t sclp_receive_mask;
 602 } __attribute__((packed));
 603
 604 /* Prepare init mask request. Called while sclp_lock is locked. */
 605 static inline void
 606 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 607 {
 608         struct init_sccb *sccb;
 609
 610         sccb = (struct init_sccb *) sclp_init_sccb;
 611         clear_page(sccb);
 612         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 613         sclp_init_req.command = SCLP_CMDW_WRITEMASK;
 614         sclp_init_req.status = SCLP_REQ_FILLED;
 615         sclp_init_req.start_count = 0;
 616         sclp_init_req.callback = NULL;
 617         sclp_init_req.callback_data = NULL;
 618         sclp_init_req.sccb = sccb;
 619         sccb->header.length = sizeof(struct init_sccb);
 620         sccb->mask_length = sizeof(sccb_mask_t);
 621         sccb->receive_mask = receive_mask;
 622         sccb->send_mask = send_mask;
 623         sccb->sclp_receive_mask = 0;
 624         sccb->sclp_send_mask = 0;
 625 }
 626
 627 /* Start init mask request. If calculate is non-zero, calculate the mask as
 628  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 629  * success, non-zero otherwise. */
 630 static int
 631 sclp_init_mask(int calculate)
 632 {
 633         unsigned long flags;
 634         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 635         sccb_mask_t receive_mask;
 636         sccb_mask_t send_mask;
 637         int retry;
 638         int rc;
 639         unsigned long wait;
 640
 641         spin_lock_irqsave(&sclp_lock, flags);
 642         /* Check if interface is in appropriate state */
 643         if (sclp_mask_state != sclp_mask_state_idle) {
 644                 spin_unlock_irqrestore(&sclp_lock, flags);
 645                 return -EBUSY;
 646         }
 647         if (sclp_activation_state == sclp_activation_state_inactive) {
 648                 spin_unlock_irqrestore(&sclp_lock, flags);
 649                 return -EINVAL;
 650         }
 651         sclp_mask_state = sclp_mask_state_initializing;
 652         /* Determine mask */
 653         if (calculate)
 654                 __sclp_get_mask(&receive_mask, &send_mask);
 655         else {
 656                 receive_mask = 0;
 657                 send_mask = 0;
 658         }
 659         rc = -EIO;
 660         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 661                 /* Prepare request */
 662                 __sclp_make_init_req(receive_mask, send_mask);
 663                 spin_unlock_irqrestore(&sclp_lock, flags);
 664                 if (sclp_add_request(&sclp_init_req)) {
 665                         /* Try again later */
 666                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 667                         while (time_before(jiffies, wait))
 668                                 sclp_sync_wait();
 669                         spin_lock_irqsave(&sclp_lock, flags);
 670                         continue;
 671                 }
 672                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 673                        sclp_init_req.status != SCLP_REQ_FAILED)
 674                         sclp_sync_wait();
 675                 spin_lock_irqsave(&sclp_lock, flags);
 676                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 677                     sccb->header.response_code == 0x20) {
 678                         /* Successful request */
 679                         if (calculate) {
 680                                 sclp_receive_mask = sccb->sclp_receive_mask;
 681                                 sclp_send_mask = sccb->sclp_send_mask;
 682                         } else {
 683                                 sclp_receive_mask = 0;
 684                                 sclp_send_mask = 0;
 685                         }
 686                         spin_unlock_irqrestore(&sclp_lock, flags);
 687                         sclp_dispatch_state_change();
 688                         spin_lock_irqsave(&sclp_lock, flags);
 689                         rc = 0;
 690                         break;
 691                 }
 692         }
 693         sclp_mask_state = sclp_mask_state_idle;
 694         spin_unlock_irqrestore(&sclp_lock, flags);
 695         return rc;
 696 }
 697
 698 /* Deactivate SCLP interface. On success, new requests will be rejected,
 699  * events will no longer be dispatched. Return 0 on success, non-zero
 700  * otherwise. */
 701 int
 702 sclp_deactivate(void)
 703 {
 704         unsigned long flags;
 705         int rc;
 706
 707         spin_lock_irqsave(&sclp_lock, flags);
 708         /* Deactivate can only be called when active */
 709         if (sclp_activation_state != sclp_activation_state_active) {
 710                 spin_unlock_irqrestore(&sclp_lock, flags);
 711                 return -EINVAL;
 712         }
 713         sclp_activation_state = sclp_activation_state_deactivating;
 714         spin_unlock_irqrestore(&sclp_lock, flags);
 715         rc = sclp_init_mask(0);
 716         spin_lock_irqsave(&sclp_lock, flags);
 717         if (rc == 0)
 718                 sclp_activation_state = sclp_activation_state_inactive;
 719         else
 720                 sclp_activation_state = sclp_activation_state_active;
 721         spin_unlock_irqrestore(&sclp_lock, flags);
 722         return rc;
 723 }
 724
 725 EXPORT_SYMBOL(sclp_deactivate);
 726
 727 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 728  * requests will be accepted, events will be dispatched again. Return 0 on
 729  * success, non-zero otherwise. */
 730 int
 731 sclp_reactivate(void)
 732 {
 733         unsigned long flags;
 734         int rc;
 735
 736         spin_lock_irqsave(&sclp_lock, flags);
 737         /* Reactivate can only be called when inactive */
 738         if (sclp_activation_state != sclp_activation_state_inactive) {
 739                 spin_unlock_irqrestore(&sclp_lock, flags);
 740                 return -EINVAL;
 741         }
 742         sclp_activation_state = sclp_activation_state_activating;
 743         spin_unlock_irqrestore(&sclp_lock, flags);
 744         rc = sclp_init_mask(1);
 745         spin_lock_irqsave(&sclp_lock, flags);
 746         if (rc == 0)
 747                 sclp_activation_state = sclp_activation_state_active;
 748         else
 749                 sclp_activation_state = sclp_activation_state_inactive;
 750         spin_unlock_irqrestore(&sclp_lock, flags);
 751         return rc;
 752 }
 753
 754 EXPORT_SYMBOL(sclp_reactivate);
 755
 756 /* Handler for external interruption used during initialization. Modify
 757  * request state to done. */
 758 static void
 759 sclp_check_handler(struct pt_regs *regs, __u16 code)
 760 {
 761         u32 finished_sccb;
 762
 763         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 764         /* Is this the interrupt we are waiting for? */
 765         if (finished_sccb == 0)
 766                 return;
 767         if (finished_sccb != (u32) (addr_t) sclp_init_sccb) {
 768                 printk(KERN_WARNING SCLP_HEADER "unsolicited interrupt "
 769                        "for buffer at 0x%x\n", finished_sccb);
 770                 return;
 771         }
 772         spin_lock(&sclp_lock);
 773         if (sclp_running_state == sclp_running_state_running) {
 774                 sclp_init_req.status = SCLP_REQ_DONE;
 775                 sclp_running_state = sclp_running_state_idle;
 776         }
 777         spin_unlock(&sclp_lock);
 778 }
 779
 780 /* Initial init mask request timed out. Modify request state to failed. */
 781 static void
 782 sclp_check_timeout(unsigned long data)
 783 {
 784         unsigned long flags;
 785
 786         spin_lock_irqsave(&sclp_lock, flags);
 787         if (sclp_running_state == sclp_running_state_running) {
 788                 sclp_init_req.status = SCLP_REQ_FAILED;
 789                 sclp_running_state = sclp_running_state_idle;
 790         }
 791         spin_unlock_irqrestore(&sclp_lock, flags);
 792 }
 793
 794 /* Perform a check of the SCLP interface. Return zero if the interface is
 795  * available and there are no pending requests from a previous instance.
 796  * Return non-zero otherwise. */
 797 static int
 798 sclp_check_interface(void)
 799 {
 800         struct init_sccb *sccb;
 801         unsigned long flags;
 802         int retry;
 803         int rc;
 804
 805         spin_lock_irqsave(&sclp_lock, flags);
 806         /* Prepare init mask command */
 807         rc = register_early_external_interrupt(0x2401, sclp_check_handler,
 808                                                &ext_int_info_hwc);
 809         if (rc) {
 810                 spin_unlock_irqrestore(&sclp_lock, flags);
 811                 return rc;
 812         }
 813         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 814                 __sclp_make_init_req(0, 0);
 815                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 816                 rc = service_call(sclp_init_req.command, sccb);
 817                 if (rc == -EIO)
 818                         break;
 819                 sclp_init_req.status = SCLP_REQ_RUNNING;
 820                 sclp_running_state = sclp_running_state_running;
 821                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 822                                          sclp_check_timeout, 0);
 823                 spin_unlock_irqrestore(&sclp_lock, flags);
 824                 /* Enable service-signal interruption - needs to happen
 825                  * with IRQs enabled. */
 826                 ctl_set_bit(0, 9);
 827                 /* Wait for signal from interrupt or timeout */
 828                 sclp_sync_wait();
 829                 /* Disable service-signal interruption - needs to happen
 830                  * with IRQs enabled. */
 831                 ctl_clear_bit(0,9);
 832                 spin_lock_irqsave(&sclp_lock, flags);
 833                 del_timer(&sclp_request_timer);
 834                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 835                     sccb->header.response_code == 0x20) {
 836                         rc = 0;
 837                         break;
 838                 } else
 839                         rc = -EBUSY;
 840         }
 841         unregister_early_external_interrupt(0x2401, sclp_check_handler,
 842                                             &ext_int_info_hwc);
 843         spin_unlock_irqrestore(&sclp_lock, flags);
 844         return rc;
 845 }
 846
 847 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 848  * events from interfering with rebooted system. */
 849 static int
 850 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 851 {
 852         sclp_deactivate();
 853         return NOTIFY_DONE;
 854 }
 855
 856 static struct notifier_block sclp_reboot_notifier = {
 857         .notifier_call = sclp_reboot_event
 858 };
 859
 860 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
 861  * otherwise. */
 862 static int
 863 sclp_init(void)
 864 {
 865         unsigned long flags;
 866         int rc;
 867
 868         if (!MACHINE_HAS_SCLP)
 869                 return -ENODEV;
 870         spin_lock_irqsave(&sclp_lock, flags);
 871         /* Check for previous or running initialization */
 872         if (sclp_init_state != sclp_init_state_uninitialized) {
 873                 spin_unlock_irqrestore(&sclp_lock, flags);
 874                 return 0;
 875         }
 876         sclp_init_state = sclp_init_state_initializing;
 877         /* Set up variables */
 878         INIT_LIST_HEAD(&sclp_req_queue);
 879         INIT_LIST_HEAD(&sclp_reg_list);
 880         list_add(&sclp_state_change_event.list, &sclp_reg_list);
 881         init_timer(&sclp_request_timer);
 882         /* Check interface */
 883         spin_unlock_irqrestore(&sclp_lock, flags);
 884         rc = sclp_check_interface();
 885         spin_lock_irqsave(&sclp_lock, flags);
 886         if (rc) {
 887                 sclp_init_state = sclp_init_state_uninitialized;
 888                 spin_unlock_irqrestore(&sclp_lock, flags);
 889                 return rc;
 890         }
 891         /* Register reboot handler */
 892         rc = register_reboot_notifier(&sclp_reboot_notifier);
 893         if (rc) {
 894                 sclp_init_state = sclp_init_state_uninitialized;
 895                 spin_unlock_irqrestore(&sclp_lock, flags);
 896                 return rc;
 897         }
 898         /* Register interrupt handler */
 899         rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler,
 900                                                &ext_int_info_hwc);
 901         if (rc) {
 902                 unregister_reboot_notifier(&sclp_reboot_notifier);
 903                 sclp_init_state = sclp_init_state_uninitialized;
 904                 spin_unlock_irqrestore(&sclp_lock, flags);
 905                 return rc;
 906         }
 907         sclp_init_state = sclp_init_state_initialized;
 908         spin_unlock_irqrestore(&sclp_lock, flags);
 909         /* Enable service-signal external interruption - needs to happen with
 910          * IRQs enabled. */
 911         ctl_set_bit(0, 9);
 912         sclp_init_mask(1);
 913         return 0;
 914 }