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_reset_pending
  64 } sclp_running_state = sclp_running_state_idle;
  65
  66 /* Internal state: is a read request pending? */
  67 static volatile enum sclp_reading_state_t {
  68         sclp_reading_state_idle,
  69         sclp_reading_state_reading
  70 } sclp_reading_state = sclp_reading_state_idle;
  71
  72 /* Internal state: is the driver currently serving requests? */
  73 static volatile enum sclp_activation_state_t {
  74         sclp_activation_state_active,
  75         sclp_activation_state_deactivating,
  76         sclp_activation_state_inactive,
  77         sclp_activation_state_activating
  78 } sclp_activation_state = sclp_activation_state_active;
  79
  80 /* Internal state: is an init mask request pending? */
  81 static volatile enum sclp_mask_state_t {
  82         sclp_mask_state_idle,
  83         sclp_mask_state_initializing
  84 } sclp_mask_state = sclp_mask_state_idle;
  85
  86 /* Maximum retry counts */
  87 #define SCLP_INIT_RETRY         3
  88 #define SCLP_MASK_RETRY         3
  89
  90 /* Timeout intervals in seconds.*/
  91 #define SCLP_BUSY_INTERVAL      10
  92 #define SCLP_RETRY_INTERVAL     30
  93
  94 static void sclp_process_queue(void);
  95 static int sclp_init_mask(int calculate);
  96 static int sclp_init(void);
  97
  98 /* Perform service call. Return 0 on success, non-zero otherwise. */
  99 int
 100 sclp_service_call(sclp_cmdw_t command, void *sccb)
 101 {
 102         int cc;
 103
 104         asm volatile(
 105                 "       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
 106                 "       ipm     %0\n"
 107                 "       srl     %0,28"
 108                 : "=&d" (cc) : "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 static inline void __sclp_make_read_req(void);
 118
 119 static void
 120 __sclp_queue_read_req(void)
 121 {
 122         if (sclp_reading_state == sclp_reading_state_idle) {
 123                 sclp_reading_state = sclp_reading_state_reading;
 124                 __sclp_make_read_req();
 125                 /* Add request to head of queue */
 126                 list_add(&sclp_read_req.list, &sclp_req_queue);
 127         }
 128 }
 129
 130 /* Set up request retry timer. Called while sclp_lock is locked. */
 131 static inline void
 132 __sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
 133                          unsigned long data)
 134 {
 135         del_timer(&sclp_request_timer);
 136         sclp_request_timer.function = function;
 137         sclp_request_timer.data = data;
 138         sclp_request_timer.expires = jiffies + time;
 139         add_timer(&sclp_request_timer);
 140 }
 141
 142 /* Request timeout handler. Restart the request queue. If DATA is non-zero,
 143  * force restart of running request. */
 144 static void
 145 sclp_request_timeout(unsigned long data)
 146 {
 147         unsigned long flags;
 148
 149         spin_lock_irqsave(&sclp_lock, flags);
 150         if (data) {
 151                 if (sclp_running_state == sclp_running_state_running) {
 152                         /* Break running state and queue NOP read event request
 153                          * to get a defined interface state. */
 154                         __sclp_queue_read_req();
 155                         sclp_running_state = sclp_running_state_idle;
 156                 }
 157         } else {
 158                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 159                                          sclp_request_timeout, 0);
 160         }
 161         spin_unlock_irqrestore(&sclp_lock, flags);
 162         sclp_process_queue();
 163 }
 164
 165 /* Try to start a request. Return zero if the request was successfully
 166  * started or if it will be started at a later time. Return non-zero otherwise.
 167  * Called while sclp_lock is locked. */
 168 static int
 169 __sclp_start_request(struct sclp_req *req)
 170 {
 171         int rc;
 172
 173         if (sclp_running_state != sclp_running_state_idle)
 174                 return 0;
 175         del_timer(&sclp_request_timer);
 176         rc = sclp_service_call(req->command, req->sccb);
 177         req->start_count++;
 178
 179         if (rc == 0) {
 180                 /* Sucessfully started request */
 181                 req->status = SCLP_REQ_RUNNING;
 182                 sclp_running_state = sclp_running_state_running;
 183                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 184                                          sclp_request_timeout, 1);
 185                 return 0;
 186         } else if (rc == -EBUSY) {
 187                 /* Try again later */
 188                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 189                                          sclp_request_timeout, 0);
 190                 return 0;
 191         }
 192         /* Request failed */
 193         req->status = SCLP_REQ_FAILED;
 194         return rc;
 195 }
 196
 197 /* Try to start queued requests. */
 198 static void
 199 sclp_process_queue(void)
 200 {
 201         struct sclp_req *req;
 202         int rc;
 203         unsigned long flags;
 204
 205         spin_lock_irqsave(&sclp_lock, flags);
 206         if (sclp_running_state != sclp_running_state_idle) {
 207                 spin_unlock_irqrestore(&sclp_lock, flags);
 208                 return;
 209         }
 210         del_timer(&sclp_request_timer);
 211         while (!list_empty(&sclp_req_queue)) {
 212                 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
 213                 rc = __sclp_start_request(req);
 214                 if (rc == 0)
 215                         break;
 216                 /* Request failed */
 217                 if (req->start_count > 1) {
 218                         /* Cannot abort already submitted request - could still
 219                          * be active at the SCLP */
 220                         __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 221                                                  sclp_request_timeout, 0);
 222                         break;
 223                 }
 224                 /* Post-processing for aborted request */
 225                 list_del(&req->list);
 226                 if (req->callback) {
 227                         spin_unlock_irqrestore(&sclp_lock, flags);
 228                         req->callback(req, req->callback_data);
 229                         spin_lock_irqsave(&sclp_lock, flags);
 230                 }
 231         }
 232         spin_unlock_irqrestore(&sclp_lock, flags);
 233 }
 234
 235 /* Queue a new request. Return zero on success, non-zero otherwise. */
 236 int
 237 sclp_add_request(struct sclp_req *req)
 238 {
 239         unsigned long flags;
 240         int rc;
 241
 242         spin_lock_irqsave(&sclp_lock, flags);
 243         if ((sclp_init_state != sclp_init_state_initialized ||
 244              sclp_activation_state != sclp_activation_state_active) &&
 245             req != &sclp_init_req) {
 246                 spin_unlock_irqrestore(&sclp_lock, flags);
 247                 return -EIO;
 248         }
 249         req->status = SCLP_REQ_QUEUED;
 250         req->start_count = 0;
 251         list_add_tail(&req->list, &sclp_req_queue);
 252         rc = 0;
 253         /* Start if request is first in list */
 254         if (sclp_running_state == sclp_running_state_idle &&
 255             req->list.prev == &sclp_req_queue) {
 256                 rc = __sclp_start_request(req);
 257                 if (rc)
 258                         list_del(&req->list);
 259         }
 260         spin_unlock_irqrestore(&sclp_lock, flags);
 261         return rc;
 262 }
 263
 264 EXPORT_SYMBOL(sclp_add_request);
 265
 266 /* Dispatch events found in request buffer to registered listeners. Return 0
 267  * if all events were dispatched, non-zero otherwise. */
 268 static int
 269 sclp_dispatch_evbufs(struct sccb_header *sccb)
 270 {
 271         unsigned long flags;
 272         struct evbuf_header *evbuf;
 273         struct list_head *l;
 274         struct sclp_register *reg;
 275         int offset;
 276         int rc;
 277
 278         spin_lock_irqsave(&sclp_lock, flags);
 279         rc = 0;
 280         for (offset = sizeof(struct sccb_header); offset < sccb->length;
 281              offset += evbuf->length) {
 282                 /* Search for event handler */
 283                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 284                 reg = NULL;
 285                 list_for_each(l, &sclp_reg_list) {
 286                         reg = list_entry(l, struct sclp_register, list);
 287                         if (reg->receive_mask & (1 << (32 - evbuf->type)))
 288                                 break;
 289                         else
 290                                 reg = NULL;
 291                 }
 292                 if (reg && reg->receiver_fn) {
 293                         spin_unlock_irqrestore(&sclp_lock, flags);
 294                         reg->receiver_fn(evbuf);
 295                         spin_lock_irqsave(&sclp_lock, flags);
 296                 } else if (reg == NULL)
 297                         rc = -ENOSYS;
 298         }
 299         spin_unlock_irqrestore(&sclp_lock, flags);
 300         return rc;
 301 }
 302
 303 /* Read event data request callback. */
 304 static void
 305 sclp_read_cb(struct sclp_req *req, void *data)
 306 {
 307         unsigned long flags;
 308         struct sccb_header *sccb;
 309
 310         sccb = (struct sccb_header *) req->sccb;
 311         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 312             sccb->response_code == 0x220))
 313                 sclp_dispatch_evbufs(sccb);
 314         spin_lock_irqsave(&sclp_lock, flags);
 315         sclp_reading_state = sclp_reading_state_idle;
 316         spin_unlock_irqrestore(&sclp_lock, flags);
 317 }
 318
 319 /* Prepare read event data request. Called while sclp_lock is locked. */
 320 static inline void
 321 __sclp_make_read_req(void)
 322 {
 323         struct sccb_header *sccb;
 324
 325         sccb = (struct sccb_header *) sclp_read_sccb;
 326         clear_page(sccb);
 327         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 328         sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
 329         sclp_read_req.status = SCLP_REQ_QUEUED;
 330         sclp_read_req.start_count = 0;
 331         sclp_read_req.callback = sclp_read_cb;
 332         sclp_read_req.sccb = sccb;
 333         sccb->length = PAGE_SIZE;
 334         sccb->function_code = 0;
 335         sccb->control_mask[2] = 0x80;
 336 }
 337
 338 /* Search request list for request with matching sccb. Return request if found,
 339  * NULL otherwise. Called while sclp_lock is locked. */
 340 static inline struct sclp_req *
 341 __sclp_find_req(u32 sccb)
 342 {
 343         struct list_head *l;
 344         struct sclp_req *req;
 345
 346         list_for_each(l, &sclp_req_queue) {
 347                 req = list_entry(l, struct sclp_req, list);
 348                 if (sccb == (u32) (addr_t) req->sccb)
 349                                 return req;
 350         }
 351         return NULL;
 352 }
 353
 354 /* Handler for external interruption. Perform request post-processing.
 355  * Prepare read event data request if necessary. Start processing of next
 356  * request on queue. */
 357 static void
 358 sclp_interrupt_handler(__u16 code)
 359 {
 360         struct sclp_req *req;
 361         u32 finished_sccb;
 362         u32 evbuf_pending;
 363
 364         spin_lock(&sclp_lock);
 365         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 366         evbuf_pending = S390_lowcore.ext_params & 0x3;
 367         if (finished_sccb) {
 368                 del_timer(&sclp_request_timer);
 369                 sclp_running_state = sclp_running_state_reset_pending;
 370                 req = __sclp_find_req(finished_sccb);
 371                 if (req) {
 372                         /* Request post-processing */
 373                         list_del(&req->list);
 374                         req->status = SCLP_REQ_DONE;
 375                         if (req->callback) {
 376                                 spin_unlock(&sclp_lock);
 377                                 req->callback(req, req->callback_data);
 378                                 spin_lock(&sclp_lock);
 379                         }
 380                 }
 381                 sclp_running_state = sclp_running_state_idle;
 382         }
 383         if (evbuf_pending && sclp_receive_mask != 0 &&
 384             sclp_activation_state == sclp_activation_state_active)
 385                 __sclp_queue_read_req();
 386         spin_unlock(&sclp_lock);
 387         sclp_process_queue();
 388 }
 389
 390 /* Convert interval in jiffies to TOD ticks. */
 391 static inline u64
 392 sclp_tod_from_jiffies(unsigned long jiffies)
 393 {
 394         return (u64) (jiffies / HZ) << 32;
 395 }
 396
 397 /* Wait until a currently running request finished. Note: while this function
 398  * is running, no timers are served on the calling CPU. */
 399 void
 400 sclp_sync_wait(void)
 401 {
 402         unsigned long flags;
 403         unsigned long cr0, cr0_sync;
 404         u64 timeout;
 405         int irq_context;
 406
 407         /* We'll be disabling timer interrupts, so we need a custom timeout
 408          * mechanism */
 409         timeout = 0;
 410         if (timer_pending(&sclp_request_timer)) {
 411                 /* Get timeout TOD value */
 412                 timeout = get_clock() +
 413                           sclp_tod_from_jiffies(sclp_request_timer.expires -
 414                                                 jiffies);
 415         }
 416         local_irq_save(flags);
 417         /* Prevent bottom half from executing once we force interrupts open */
 418         irq_context = in_interrupt();
 419         if (!irq_context)
 420                 local_bh_disable();
 421         /* Enable service-signal interruption, disable timer interrupts */
 422         trace_hardirqs_on();
 423         __ctl_store(cr0, 0, 0);
 424         cr0_sync = cr0;
 425         cr0_sync |= 0x00000200;
 426         cr0_sync &= 0xFFFFF3AC;
 427         __ctl_load(cr0_sync, 0, 0);
 428         __raw_local_irq_stosm(0x01);
 429         /* Loop until driver state indicates finished request */
 430         while (sclp_running_state != sclp_running_state_idle) {
 431                 /* Check for expired request timer */
 432                 if (timer_pending(&sclp_request_timer) &&
 433                     get_clock() > timeout &&
 434                     del_timer(&sclp_request_timer))
 435                         sclp_request_timer.function(sclp_request_timer.data);
 436                 cpu_relax();
 437         }
 438         local_irq_disable();
 439         __ctl_load(cr0, 0, 0);
 440         if (!irq_context)
 441                 _local_bh_enable();
 442         local_irq_restore(flags);
 443 }
 444
 445 EXPORT_SYMBOL(sclp_sync_wait);
 446
 447 /* Dispatch changes in send and receive mask to registered listeners. */
 448 static void
 449 sclp_dispatch_state_change(void)
 450 {
 451         struct list_head *l;
 452         struct sclp_register *reg;
 453         unsigned long flags;
 454         sccb_mask_t receive_mask;
 455         sccb_mask_t send_mask;
 456
 457         do {
 458                 spin_lock_irqsave(&sclp_lock, flags);
 459                 reg = NULL;
 460                 list_for_each(l, &sclp_reg_list) {
 461                         reg = list_entry(l, struct sclp_register, list);
 462                         receive_mask = reg->receive_mask & sclp_receive_mask;
 463                         send_mask = reg->send_mask & sclp_send_mask;
 464                         if (reg->sclp_receive_mask != receive_mask ||
 465                             reg->sclp_send_mask != send_mask) {
 466                                 reg->sclp_receive_mask = receive_mask;
 467                                 reg->sclp_send_mask = send_mask;
 468                                 break;
 469                         } else
 470                                 reg = NULL;
 471                 }
 472                 spin_unlock_irqrestore(&sclp_lock, flags);
 473                 if (reg && reg->state_change_fn)
 474                         reg->state_change_fn(reg);
 475         } while (reg);
 476 }
 477
 478 struct sclp_statechangebuf {
 479         struct evbuf_header     header;
 480         u8              validity_sclp_active_facility_mask : 1;
 481         u8              validity_sclp_receive_mask : 1;
 482         u8              validity_sclp_send_mask : 1;
 483         u8              validity_read_data_function_mask : 1;
 484         u16             _zeros : 12;
 485         u16             mask_length;
 486         u64             sclp_active_facility_mask;
 487         sccb_mask_t     sclp_receive_mask;
 488         sccb_mask_t     sclp_send_mask;
 489         u32             read_data_function_mask;
 490 } __attribute__((packed));
 491
 492
 493 /* State change event callback. Inform listeners of changes. */
 494 static void
 495 sclp_state_change_cb(struct evbuf_header *evbuf)
 496 {
 497         unsigned long flags;
 498         struct sclp_statechangebuf *scbuf;
 499
 500         scbuf = (struct sclp_statechangebuf *) evbuf;
 501         if (scbuf->mask_length != sizeof(sccb_mask_t))
 502                 return;
 503         spin_lock_irqsave(&sclp_lock, flags);
 504         if (scbuf->validity_sclp_receive_mask)
 505                 sclp_receive_mask = scbuf->sclp_receive_mask;
 506         if (scbuf->validity_sclp_send_mask)
 507                 sclp_send_mask = scbuf->sclp_send_mask;
 508         spin_unlock_irqrestore(&sclp_lock, flags);
 509         sclp_dispatch_state_change();
 510 }
 511
 512 static struct sclp_register sclp_state_change_event = {
 513         .receive_mask = EvTyp_StateChange_Mask,
 514         .receiver_fn = sclp_state_change_cb
 515 };
 516
 517 /* Calculate receive and send mask of currently registered listeners.
 518  * Called while sclp_lock is locked. */
 519 static inline void
 520 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 521 {
 522         struct list_head *l;
 523         struct sclp_register *t;
 524
 525         *receive_mask = 0;
 526         *send_mask = 0;
 527         list_for_each(l, &sclp_reg_list) {
 528                 t = list_entry(l, struct sclp_register, list);
 529                 *receive_mask |= t->receive_mask;
 530                 *send_mask |= t->send_mask;
 531         }
 532 }
 533
 534 /* Register event listener. Return 0 on success, non-zero otherwise. */
 535 int
 536 sclp_register(struct sclp_register *reg)
 537 {
 538         unsigned long flags;
 539         sccb_mask_t receive_mask;
 540         sccb_mask_t send_mask;
 541         int rc;
 542
 543         rc = sclp_init();
 544         if (rc)
 545                 return rc;
 546         spin_lock_irqsave(&sclp_lock, flags);
 547         /* Check event mask for collisions */
 548         __sclp_get_mask(&receive_mask, &send_mask);
 549         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 550                 spin_unlock_irqrestore(&sclp_lock, flags);
 551                 return -EBUSY;
 552         }
 553         /* Trigger initial state change callback */
 554         reg->sclp_receive_mask = 0;
 555         reg->sclp_send_mask = 0;
 556         list_add(&reg->list, &sclp_reg_list);
 557         spin_unlock_irqrestore(&sclp_lock, flags);
 558         rc = sclp_init_mask(1);
 559         if (rc) {
 560                 spin_lock_irqsave(&sclp_lock, flags);
 561                 list_del(&reg->list);
 562                 spin_unlock_irqrestore(&sclp_lock, flags);
 563         }
 564         return rc;
 565 }
 566
 567 EXPORT_SYMBOL(sclp_register);
 568
 569 /* Unregister event listener. */
 570 void
 571 sclp_unregister(struct sclp_register *reg)
 572 {
 573         unsigned long flags;
 574
 575         spin_lock_irqsave(&sclp_lock, flags);
 576         list_del(&reg->list);
 577         spin_unlock_irqrestore(&sclp_lock, flags);
 578         sclp_init_mask(1);
 579 }
 580
 581 EXPORT_SYMBOL(sclp_unregister);
 582
 583 /* Remove event buffers which are marked processed. Return the number of
 584  * remaining event buffers. */
 585 int
 586 sclp_remove_processed(struct sccb_header *sccb)
 587 {
 588         struct evbuf_header *evbuf;
 589         int unprocessed;
 590         u16 remaining;
 591
 592         evbuf = (struct evbuf_header *) (sccb + 1);
 593         unprocessed = 0;
 594         remaining = sccb->length - sizeof(struct sccb_header);
 595         while (remaining > 0) {
 596                 remaining -= evbuf->length;
 597                 if (evbuf->flags & 0x80) {
 598                         sccb->length -= evbuf->length;
 599                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 600                                remaining);
 601                 } else {
 602                         unprocessed++;
 603                         evbuf = (struct evbuf_header *)
 604                                         ((addr_t) evbuf + evbuf->length);
 605                 }
 606         }
 607         return unprocessed;
 608 }
 609
 610 EXPORT_SYMBOL(sclp_remove_processed);
 611
 612 struct init_sccb {
 613         struct sccb_header header;
 614         u16 _reserved;
 615         u16 mask_length;
 616         sccb_mask_t receive_mask;
 617         sccb_mask_t send_mask;
 618         sccb_mask_t sclp_send_mask;
 619         sccb_mask_t sclp_receive_mask;
 620 } __attribute__((packed));
 621
 622 /* Prepare init mask request. Called while sclp_lock is locked. */
 623 static inline void
 624 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 625 {
 626         struct init_sccb *sccb;
 627
 628         sccb = (struct init_sccb *) sclp_init_sccb;
 629         clear_page(sccb);
 630         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 631         sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 632         sclp_init_req.status = SCLP_REQ_FILLED;
 633         sclp_init_req.start_count = 0;
 634         sclp_init_req.callback = NULL;
 635         sclp_init_req.callback_data = NULL;
 636         sclp_init_req.sccb = sccb;
 637         sccb->header.length = sizeof(struct init_sccb);
 638         sccb->mask_length = sizeof(sccb_mask_t);
 639         sccb->receive_mask = receive_mask;
 640         sccb->send_mask = send_mask;
 641         sccb->sclp_receive_mask = 0;
 642         sccb->sclp_send_mask = 0;
 643 }
 644
 645 /* Start init mask request. If calculate is non-zero, calculate the mask as
 646  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 647  * success, non-zero otherwise. */
 648 static int
 649 sclp_init_mask(int calculate)
 650 {
 651         unsigned long flags;
 652         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 653         sccb_mask_t receive_mask;
 654         sccb_mask_t send_mask;
 655         int retry;
 656         int rc;
 657         unsigned long wait;
 658
 659         spin_lock_irqsave(&sclp_lock, flags);
 660         /* Check if interface is in appropriate state */
 661         if (sclp_mask_state != sclp_mask_state_idle) {
 662                 spin_unlock_irqrestore(&sclp_lock, flags);
 663                 return -EBUSY;
 664         }
 665         if (sclp_activation_state == sclp_activation_state_inactive) {
 666                 spin_unlock_irqrestore(&sclp_lock, flags);
 667                 return -EINVAL;
 668         }
 669         sclp_mask_state = sclp_mask_state_initializing;
 670         /* Determine mask */
 671         if (calculate)
 672                 __sclp_get_mask(&receive_mask, &send_mask);
 673         else {
 674                 receive_mask = 0;
 675                 send_mask = 0;
 676         }
 677         rc = -EIO;
 678         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 679                 /* Prepare request */
 680                 __sclp_make_init_req(receive_mask, send_mask);
 681                 spin_unlock_irqrestore(&sclp_lock, flags);
 682                 if (sclp_add_request(&sclp_init_req)) {
 683                         /* Try again later */
 684                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 685                         while (time_before(jiffies, wait))
 686                                 sclp_sync_wait();
 687                         spin_lock_irqsave(&sclp_lock, flags);
 688                         continue;
 689                 }
 690                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 691                        sclp_init_req.status != SCLP_REQ_FAILED)
 692                         sclp_sync_wait();
 693                 spin_lock_irqsave(&sclp_lock, flags);
 694                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 695                     sccb->header.response_code == 0x20) {
 696                         /* Successful request */
 697                         if (calculate) {
 698                                 sclp_receive_mask = sccb->sclp_receive_mask;
 699                                 sclp_send_mask = sccb->sclp_send_mask;
 700                         } else {
 701                                 sclp_receive_mask = 0;
 702                                 sclp_send_mask = 0;
 703                         }
 704                         spin_unlock_irqrestore(&sclp_lock, flags);
 705                         sclp_dispatch_state_change();
 706                         spin_lock_irqsave(&sclp_lock, flags);
 707                         rc = 0;
 708                         break;
 709                 }
 710         }
 711         sclp_mask_state = sclp_mask_state_idle;
 712         spin_unlock_irqrestore(&sclp_lock, flags);
 713         return rc;
 714 }
 715
 716 /* Deactivate SCLP interface. On success, new requests will be rejected,
 717  * events will no longer be dispatched. Return 0 on success, non-zero
 718  * otherwise. */
 719 int
 720 sclp_deactivate(void)
 721 {
 722         unsigned long flags;
 723         int rc;
 724
 725         spin_lock_irqsave(&sclp_lock, flags);
 726         /* Deactivate can only be called when active */
 727         if (sclp_activation_state != sclp_activation_state_active) {
 728                 spin_unlock_irqrestore(&sclp_lock, flags);
 729                 return -EINVAL;
 730         }
 731         sclp_activation_state = sclp_activation_state_deactivating;
 732         spin_unlock_irqrestore(&sclp_lock, flags);
 733         rc = sclp_init_mask(0);
 734         spin_lock_irqsave(&sclp_lock, flags);
 735         if (rc == 0)
 736                 sclp_activation_state = sclp_activation_state_inactive;
 737         else
 738                 sclp_activation_state = sclp_activation_state_active;
 739         spin_unlock_irqrestore(&sclp_lock, flags);
 740         return rc;
 741 }
 742
 743 EXPORT_SYMBOL(sclp_deactivate);
 744
 745 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 746  * requests will be accepted, events will be dispatched again. Return 0 on
 747  * success, non-zero otherwise. */
 748 int
 749 sclp_reactivate(void)
 750 {
 751         unsigned long flags;
 752         int rc;
 753
 754         spin_lock_irqsave(&sclp_lock, flags);
 755         /* Reactivate can only be called when inactive */
 756         if (sclp_activation_state != sclp_activation_state_inactive) {
 757                 spin_unlock_irqrestore(&sclp_lock, flags);
 758                 return -EINVAL;
 759         }
 760         sclp_activation_state = sclp_activation_state_activating;
 761         spin_unlock_irqrestore(&sclp_lock, flags);
 762         rc = sclp_init_mask(1);
 763         spin_lock_irqsave(&sclp_lock, flags);
 764         if (rc == 0)
 765                 sclp_activation_state = sclp_activation_state_active;
 766         else
 767                 sclp_activation_state = sclp_activation_state_inactive;
 768         spin_unlock_irqrestore(&sclp_lock, flags);
 769         return rc;
 770 }
 771
 772 EXPORT_SYMBOL(sclp_reactivate);
 773
 774 /* Handler for external interruption used during initialization. Modify
 775  * request state to done. */
 776 static void
 777 sclp_check_handler(__u16 code)
 778 {
 779         u32 finished_sccb;
 780
 781         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 782         /* Is this the interrupt we are waiting for? */
 783         if (finished_sccb == 0)
 784                 return;
 785         if (finished_sccb != (u32) (addr_t) sclp_init_sccb) {
 786                 printk(KERN_WARNING SCLP_HEADER "unsolicited interrupt "
 787                        "for buffer at 0x%x\n", finished_sccb);
 788                 return;
 789         }
 790         spin_lock(&sclp_lock);
 791         if (sclp_running_state == sclp_running_state_running) {
 792                 sclp_init_req.status = SCLP_REQ_DONE;
 793                 sclp_running_state = sclp_running_state_idle;
 794         }
 795         spin_unlock(&sclp_lock);
 796 }
 797
 798 /* Initial init mask request timed out. Modify request state to failed. */
 799 static void
 800 sclp_check_timeout(unsigned long data)
 801 {
 802         unsigned long flags;
 803
 804         spin_lock_irqsave(&sclp_lock, flags);
 805         if (sclp_running_state == sclp_running_state_running) {
 806                 sclp_init_req.status = SCLP_REQ_FAILED;
 807                 sclp_running_state = sclp_running_state_idle;
 808         }
 809         spin_unlock_irqrestore(&sclp_lock, flags);
 810 }
 811
 812 /* Perform a check of the SCLP interface. Return zero if the interface is
 813  * available and there are no pending requests from a previous instance.
 814  * Return non-zero otherwise. */
 815 static int
 816 sclp_check_interface(void)
 817 {
 818         struct init_sccb *sccb;
 819         unsigned long flags;
 820         int retry;
 821         int rc;
 822
 823         spin_lock_irqsave(&sclp_lock, flags);
 824         /* Prepare init mask command */
 825         rc = register_early_external_interrupt(0x2401, sclp_check_handler,
 826                                                &ext_int_info_hwc);
 827         if (rc) {
 828                 spin_unlock_irqrestore(&sclp_lock, flags);
 829                 return rc;
 830         }
 831         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 832                 __sclp_make_init_req(0, 0);
 833                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 834                 rc = sclp_service_call(sclp_init_req.command, sccb);
 835                 if (rc == -EIO)
 836                         break;
 837                 sclp_init_req.status = SCLP_REQ_RUNNING;
 838                 sclp_running_state = sclp_running_state_running;
 839                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 840                                          sclp_check_timeout, 0);
 841                 spin_unlock_irqrestore(&sclp_lock, flags);
 842                 /* Enable service-signal interruption - needs to happen
 843                  * with IRQs enabled. */
 844                 ctl_set_bit(0, 9);
 845                 /* Wait for signal from interrupt or timeout */
 846                 sclp_sync_wait();
 847                 /* Disable service-signal interruption - needs to happen
 848                  * with IRQs enabled. */
 849                 ctl_clear_bit(0,9);
 850                 spin_lock_irqsave(&sclp_lock, flags);
 851                 del_timer(&sclp_request_timer);
 852                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 853                     sccb->header.response_code == 0x20) {
 854                         rc = 0;
 855                         break;
 856                 } else
 857                         rc = -EBUSY;
 858         }
 859         unregister_early_external_interrupt(0x2401, sclp_check_handler,
 860                                             &ext_int_info_hwc);
 861         spin_unlock_irqrestore(&sclp_lock, flags);
 862         return rc;
 863 }
 864
 865 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 866  * events from interfering with rebooted system. */
 867 static int
 868 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 869 {
 870         sclp_deactivate();
 871         return NOTIFY_DONE;
 872 }
 873
 874 static struct notifier_block sclp_reboot_notifier = {
 875         .notifier_call = sclp_reboot_event
 876 };
 877
 878 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
 879  * otherwise. */
 880 static int
 881 sclp_init(void)
 882 {
 883         unsigned long flags;
 884         int rc;
 885
 886         if (!MACHINE_HAS_SCLP)
 887                 return -ENODEV;
 888         spin_lock_irqsave(&sclp_lock, flags);
 889         /* Check for previous or running initialization */
 890         if (sclp_init_state != sclp_init_state_uninitialized) {
 891                 spin_unlock_irqrestore(&sclp_lock, flags);
 892                 return 0;
 893         }
 894         sclp_init_state = sclp_init_state_initializing;
 895         /* Set up variables */
 896         INIT_LIST_HEAD(&sclp_req_queue);
 897         INIT_LIST_HEAD(&sclp_reg_list);
 898         list_add(&sclp_state_change_event.list, &sclp_reg_list);
 899         init_timer(&sclp_request_timer);
 900         /* Check interface */
 901         spin_unlock_irqrestore(&sclp_lock, flags);
 902         rc = sclp_check_interface();
 903         spin_lock_irqsave(&sclp_lock, flags);
 904         if (rc) {
 905                 sclp_init_state = sclp_init_state_uninitialized;
 906                 spin_unlock_irqrestore(&sclp_lock, flags);
 907                 return rc;
 908         }
 909         /* Register reboot handler */
 910         rc = register_reboot_notifier(&sclp_reboot_notifier);
 911         if (rc) {
 912                 sclp_init_state = sclp_init_state_uninitialized;
 913                 spin_unlock_irqrestore(&sclp_lock, flags);
 914                 return rc;
 915         }
 916         /* Register interrupt handler */
 917         rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler,
 918                                                &ext_int_info_hwc);
 919         if (rc) {
 920                 unregister_reboot_notifier(&sclp_reboot_notifier);
 921                 sclp_init_state = sclp_init_state_uninitialized;
 922                 spin_unlock_irqrestore(&sclp_lock, flags);
 923                 return rc;
 924         }
 925         sclp_init_state = sclp_init_state_initialized;
 926         spin_unlock_irqrestore(&sclp_lock, flags);
 927         /* Enable service-signal external interruption - needs to happen with
 928          * IRQs enabled. */
 929         ctl_set_bit(0, 9);
 930         sclp_init_mask(1);
 931         return 0;
 932 }