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 static int
 100 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 = 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_READDATA;
 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                 barrier();
 437                 cpu_relax();
 438         }
 439         local_irq_disable();
 440         __ctl_load(cr0, 0, 0);
 441         if (!irq_context)
 442                 _local_bh_enable();
 443         local_irq_restore(flags);
 444 }
 445
 446 EXPORT_SYMBOL(sclp_sync_wait);
 447
 448 /* Dispatch changes in send and receive mask to registered listeners. */
 449 static inline void
 450 sclp_dispatch_state_change(void)
 451 {
 452         struct list_head *l;
 453         struct sclp_register *reg;
 454         unsigned long flags;
 455         sccb_mask_t receive_mask;
 456         sccb_mask_t send_mask;
 457
 458         do {
 459                 spin_lock_irqsave(&sclp_lock, flags);
 460                 reg = NULL;
 461                 list_for_each(l, &sclp_reg_list) {
 462                         reg = list_entry(l, struct sclp_register, list);
 463                         receive_mask = reg->receive_mask & sclp_receive_mask;
 464                         send_mask = reg->send_mask & sclp_send_mask;
 465                         if (reg->sclp_receive_mask != receive_mask ||
 466                             reg->sclp_send_mask != send_mask) {
 467                                 reg->sclp_receive_mask = receive_mask;
 468                                 reg->sclp_send_mask = send_mask;
 469                                 break;
 470                         } else
 471                                 reg = NULL;
 472                 }
 473                 spin_unlock_irqrestore(&sclp_lock, flags);
 474                 if (reg && reg->state_change_fn)
 475                         reg->state_change_fn(reg);
 476         } while (reg);
 477 }
 478
 479 struct sclp_statechangebuf {
 480         struct evbuf_header     header;
 481         u8              validity_sclp_active_facility_mask : 1;
 482         u8              validity_sclp_receive_mask : 1;
 483         u8              validity_sclp_send_mask : 1;
 484         u8              validity_read_data_function_mask : 1;
 485         u16             _zeros : 12;
 486         u16             mask_length;
 487         u64             sclp_active_facility_mask;
 488         sccb_mask_t     sclp_receive_mask;
 489         sccb_mask_t     sclp_send_mask;
 490         u32             read_data_function_mask;
 491 } __attribute__((packed));
 492
 493
 494 /* State change event callback. Inform listeners of changes. */
 495 static void
 496 sclp_state_change_cb(struct evbuf_header *evbuf)
 497 {
 498         unsigned long flags;
 499         struct sclp_statechangebuf *scbuf;
 500
 501         scbuf = (struct sclp_statechangebuf *) evbuf;
 502         if (scbuf->mask_length != sizeof(sccb_mask_t))
 503                 return;
 504         spin_lock_irqsave(&sclp_lock, flags);
 505         if (scbuf->validity_sclp_receive_mask)
 506                 sclp_receive_mask = scbuf->sclp_receive_mask;
 507         if (scbuf->validity_sclp_send_mask)
 508                 sclp_send_mask = scbuf->sclp_send_mask;
 509         spin_unlock_irqrestore(&sclp_lock, flags);
 510         sclp_dispatch_state_change();
 511 }
 512
 513 static struct sclp_register sclp_state_change_event = {
 514         .receive_mask = EvTyp_StateChange_Mask,
 515         .receiver_fn = sclp_state_change_cb
 516 };
 517
 518 /* Calculate receive and send mask of currently registered listeners.
 519  * Called while sclp_lock is locked. */
 520 static inline void
 521 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 522 {
 523         struct list_head *l;
 524         struct sclp_register *t;
 525
 526         *receive_mask = 0;
 527         *send_mask = 0;
 528         list_for_each(l, &sclp_reg_list) {
 529                 t = list_entry(l, struct sclp_register, list);
 530                 *receive_mask |= t->receive_mask;
 531                 *send_mask |= t->send_mask;
 532         }
 533 }
 534
 535 /* Register event listener. Return 0 on success, non-zero otherwise. */
 536 int
 537 sclp_register(struct sclp_register *reg)
 538 {
 539         unsigned long flags;
 540         sccb_mask_t receive_mask;
 541         sccb_mask_t send_mask;
 542         int rc;
 543
 544         rc = sclp_init();
 545         if (rc)
 546                 return rc;
 547         spin_lock_irqsave(&sclp_lock, flags);
 548         /* Check event mask for collisions */
 549         __sclp_get_mask(&receive_mask, &send_mask);
 550         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 551                 spin_unlock_irqrestore(&sclp_lock, flags);
 552                 return -EBUSY;
 553         }
 554         /* Trigger initial state change callback */
 555         reg->sclp_receive_mask = 0;
 556         reg->sclp_send_mask = 0;
 557         list_add(&reg->list, &sclp_reg_list);
 558         spin_unlock_irqrestore(&sclp_lock, flags);
 559         rc = sclp_init_mask(1);
 560         if (rc) {
 561                 spin_lock_irqsave(&sclp_lock, flags);
 562                 list_del(&reg->list);
 563                 spin_unlock_irqrestore(&sclp_lock, flags);
 564         }
 565         return rc;
 566 }
 567
 568 EXPORT_SYMBOL(sclp_register);
 569
 570 /* Unregister event listener. */
 571 void
 572 sclp_unregister(struct sclp_register *reg)
 573 {
 574         unsigned long flags;
 575
 576         spin_lock_irqsave(&sclp_lock, flags);
 577         list_del(&reg->list);
 578         spin_unlock_irqrestore(&sclp_lock, flags);
 579         sclp_init_mask(1);
 580 }
 581
 582 EXPORT_SYMBOL(sclp_unregister);
 583
 584 /* Remove event buffers which are marked processed. Return the number of
 585  * remaining event buffers. */
 586 int
 587 sclp_remove_processed(struct sccb_header *sccb)
 588 {
 589         struct evbuf_header *evbuf;
 590         int unprocessed;
 591         u16 remaining;
 592
 593         evbuf = (struct evbuf_header *) (sccb + 1);
 594         unprocessed = 0;
 595         remaining = sccb->length - sizeof(struct sccb_header);
 596         while (remaining > 0) {
 597                 remaining -= evbuf->length;
 598                 if (evbuf->flags & 0x80) {
 599                         sccb->length -= evbuf->length;
 600                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 601                                remaining);
 602                 } else {
 603                         unprocessed++;
 604                         evbuf = (struct evbuf_header *)
 605                                         ((addr_t) evbuf + evbuf->length);
 606                 }
 607         }
 608         return unprocessed;
 609 }
 610
 611 EXPORT_SYMBOL(sclp_remove_processed);
 612
 613 struct init_sccb {
 614         struct sccb_header header;
 615         u16 _reserved;
 616         u16 mask_length;
 617         sccb_mask_t receive_mask;
 618         sccb_mask_t send_mask;
 619         sccb_mask_t sclp_send_mask;
 620         sccb_mask_t sclp_receive_mask;
 621 } __attribute__((packed));
 622
 623 /* Prepare init mask request. Called while sclp_lock is locked. */
 624 static inline void
 625 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 626 {
 627         struct init_sccb *sccb;
 628
 629         sccb = (struct init_sccb *) sclp_init_sccb;
 630         clear_page(sccb);
 631         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 632         sclp_init_req.command = SCLP_CMDW_WRITEMASK;
 633         sclp_init_req.status = SCLP_REQ_FILLED;
 634         sclp_init_req.start_count = 0;
 635         sclp_init_req.callback = NULL;
 636         sclp_init_req.callback_data = NULL;
 637         sclp_init_req.sccb = sccb;
 638         sccb->header.length = sizeof(struct init_sccb);
 639         sccb->mask_length = sizeof(sccb_mask_t);
 640         sccb->receive_mask = receive_mask;
 641         sccb->send_mask = send_mask;
 642         sccb->sclp_receive_mask = 0;
 643         sccb->sclp_send_mask = 0;
 644 }
 645
 646 /* Start init mask request. If calculate is non-zero, calculate the mask as
 647  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 648  * success, non-zero otherwise. */
 649 static int
 650 sclp_init_mask(int calculate)
 651 {
 652         unsigned long flags;
 653         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 654         sccb_mask_t receive_mask;
 655         sccb_mask_t send_mask;
 656         int retry;
 657         int rc;
 658         unsigned long wait;
 659
 660         spin_lock_irqsave(&sclp_lock, flags);
 661         /* Check if interface is in appropriate state */
 662         if (sclp_mask_state != sclp_mask_state_idle) {
 663                 spin_unlock_irqrestore(&sclp_lock, flags);
 664                 return -EBUSY;
 665         }
 666         if (sclp_activation_state == sclp_activation_state_inactive) {
 667                 spin_unlock_irqrestore(&sclp_lock, flags);
 668                 return -EINVAL;
 669         }
 670         sclp_mask_state = sclp_mask_state_initializing;
 671         /* Determine mask */
 672         if (calculate)
 673                 __sclp_get_mask(&receive_mask, &send_mask);
 674         else {
 675                 receive_mask = 0;
 676                 send_mask = 0;
 677         }
 678         rc = -EIO;
 679         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 680                 /* Prepare request */
 681                 __sclp_make_init_req(receive_mask, send_mask);
 682                 spin_unlock_irqrestore(&sclp_lock, flags);
 683                 if (sclp_add_request(&sclp_init_req)) {
 684                         /* Try again later */
 685                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 686                         while (time_before(jiffies, wait))
 687                                 sclp_sync_wait();
 688                         spin_lock_irqsave(&sclp_lock, flags);
 689                         continue;
 690                 }
 691                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 692                        sclp_init_req.status != SCLP_REQ_FAILED)
 693                         sclp_sync_wait();
 694                 spin_lock_irqsave(&sclp_lock, flags);
 695                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 696                     sccb->header.response_code == 0x20) {
 697                         /* Successful request */
 698                         if (calculate) {
 699                                 sclp_receive_mask = sccb->sclp_receive_mask;
 700                                 sclp_send_mask = sccb->sclp_send_mask;
 701                         } else {
 702                                 sclp_receive_mask = 0;
 703                                 sclp_send_mask = 0;
 704                         }
 705                         spin_unlock_irqrestore(&sclp_lock, flags);
 706                         sclp_dispatch_state_change();
 707                         spin_lock_irqsave(&sclp_lock, flags);
 708                         rc = 0;
 709                         break;
 710                 }
 711         }
 712         sclp_mask_state = sclp_mask_state_idle;
 713         spin_unlock_irqrestore(&sclp_lock, flags);
 714         return rc;
 715 }
 716
 717 /* Deactivate SCLP interface. On success, new requests will be rejected,
 718  * events will no longer be dispatched. Return 0 on success, non-zero
 719  * otherwise. */
 720 int
 721 sclp_deactivate(void)
 722 {
 723         unsigned long flags;
 724         int rc;
 725
 726         spin_lock_irqsave(&sclp_lock, flags);
 727         /* Deactivate can only be called when active */
 728         if (sclp_activation_state != sclp_activation_state_active) {
 729                 spin_unlock_irqrestore(&sclp_lock, flags);
 730                 return -EINVAL;
 731         }
 732         sclp_activation_state = sclp_activation_state_deactivating;
 733         spin_unlock_irqrestore(&sclp_lock, flags);
 734         rc = sclp_init_mask(0);
 735         spin_lock_irqsave(&sclp_lock, flags);
 736         if (rc == 0)
 737                 sclp_activation_state = sclp_activation_state_inactive;
 738         else
 739                 sclp_activation_state = sclp_activation_state_active;
 740         spin_unlock_irqrestore(&sclp_lock, flags);
 741         return rc;
 742 }
 743
 744 EXPORT_SYMBOL(sclp_deactivate);
 745
 746 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 747  * requests will be accepted, events will be dispatched again. Return 0 on
 748  * success, non-zero otherwise. */
 749 int
 750 sclp_reactivate(void)
 751 {
 752         unsigned long flags;
 753         int rc;
 754
 755         spin_lock_irqsave(&sclp_lock, flags);
 756         /* Reactivate can only be called when inactive */
 757         if (sclp_activation_state != sclp_activation_state_inactive) {
 758                 spin_unlock_irqrestore(&sclp_lock, flags);
 759                 return -EINVAL;
 760         }
 761         sclp_activation_state = sclp_activation_state_activating;
 762         spin_unlock_irqrestore(&sclp_lock, flags);
 763         rc = sclp_init_mask(1);
 764         spin_lock_irqsave(&sclp_lock, flags);
 765         if (rc == 0)
 766                 sclp_activation_state = sclp_activation_state_active;
 767         else
 768                 sclp_activation_state = sclp_activation_state_inactive;
 769         spin_unlock_irqrestore(&sclp_lock, flags);
 770         return rc;
 771 }
 772
 773 EXPORT_SYMBOL(sclp_reactivate);
 774
 775 /* Handler for external interruption used during initialization. Modify
 776  * request state to done. */
 777 static void
 778 sclp_check_handler(__u16 code)
 779 {
 780         u32 finished_sccb;
 781
 782         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
 783         /* Is this the interrupt we are waiting for? */
 784         if (finished_sccb == 0)
 785                 return;
 786         if (finished_sccb != (u32) (addr_t) sclp_init_sccb) {
 787                 printk(KERN_WARNING SCLP_HEADER "unsolicited interrupt "
 788                        "for buffer at 0x%x\n", finished_sccb);
 789                 return;
 790         }
 791         spin_lock(&sclp_lock);
 792         if (sclp_running_state == sclp_running_state_running) {
 793                 sclp_init_req.status = SCLP_REQ_DONE;
 794                 sclp_running_state = sclp_running_state_idle;
 795         }
 796         spin_unlock(&sclp_lock);
 797 }
 798
 799 /* Initial init mask request timed out. Modify request state to failed. */
 800 static void
 801 sclp_check_timeout(unsigned long data)
 802 {
 803         unsigned long flags;
 804
 805         spin_lock_irqsave(&sclp_lock, flags);
 806         if (sclp_running_state == sclp_running_state_running) {
 807                 sclp_init_req.status = SCLP_REQ_FAILED;
 808                 sclp_running_state = sclp_running_state_idle;
 809         }
 810         spin_unlock_irqrestore(&sclp_lock, flags);
 811 }
 812
 813 /* Perform a check of the SCLP interface. Return zero if the interface is
 814  * available and there are no pending requests from a previous instance.
 815  * Return non-zero otherwise. */
 816 static int
 817 sclp_check_interface(void)
 818 {
 819         struct init_sccb *sccb;
 820         unsigned long flags;
 821         int retry;
 822         int rc;
 823
 824         spin_lock_irqsave(&sclp_lock, flags);
 825         /* Prepare init mask command */
 826         rc = register_early_external_interrupt(0x2401, sclp_check_handler,
 827                                                &ext_int_info_hwc);
 828         if (rc) {
 829                 spin_unlock_irqrestore(&sclp_lock, flags);
 830                 return rc;
 831         }
 832         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 833                 __sclp_make_init_req(0, 0);
 834                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 835                 rc = service_call(sclp_init_req.command, sccb);
 836                 if (rc == -EIO)
 837                         break;
 838                 sclp_init_req.status = SCLP_REQ_RUNNING;
 839                 sclp_running_state = sclp_running_state_running;
 840                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 841                                          sclp_check_timeout, 0);
 842                 spin_unlock_irqrestore(&sclp_lock, flags);
 843                 /* Enable service-signal interruption - needs to happen
 844                  * with IRQs enabled. */
 845                 ctl_set_bit(0, 9);
 846                 /* Wait for signal from interrupt or timeout */
 847                 sclp_sync_wait();
 848                 /* Disable service-signal interruption - needs to happen
 849                  * with IRQs enabled. */
 850                 ctl_clear_bit(0,9);
 851                 spin_lock_irqsave(&sclp_lock, flags);
 852                 del_timer(&sclp_request_timer);
 853                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 854                     sccb->header.response_code == 0x20) {
 855                         rc = 0;
 856                         break;
 857                 } else
 858                         rc = -EBUSY;
 859         }
 860         unregister_early_external_interrupt(0x2401, sclp_check_handler,
 861                                             &ext_int_info_hwc);
 862         spin_unlock_irqrestore(&sclp_lock, flags);
 863         return rc;
 864 }
 865
 866 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 867  * events from interfering with rebooted system. */
 868 static int
 869 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 870 {
 871         sclp_deactivate();
 872         return NOTIFY_DONE;
 873 }
 874
 875 static struct notifier_block sclp_reboot_notifier = {
 876         .notifier_call = sclp_reboot_event
 877 };
 878
 879 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
 880  * otherwise. */
 881 static int
 882 sclp_init(void)
 883 {
 884         unsigned long flags;
 885         int rc;
 886
 887         if (!MACHINE_HAS_SCLP)
 888                 return -ENODEV;
 889         spin_lock_irqsave(&sclp_lock, flags);
 890         /* Check for previous or running initialization */
 891         if (sclp_init_state != sclp_init_state_uninitialized) {
 892                 spin_unlock_irqrestore(&sclp_lock, flags);
 893                 return 0;
 894         }
 895         sclp_init_state = sclp_init_state_initializing;
 896         /* Set up variables */
 897         INIT_LIST_HEAD(&sclp_req_queue);
 898         INIT_LIST_HEAD(&sclp_reg_list);
 899         list_add(&sclp_state_change_event.list, &sclp_reg_list);
 900         init_timer(&sclp_request_timer);
 901         /* Check interface */
 902         spin_unlock_irqrestore(&sclp_lock, flags);
 903         rc = sclp_check_interface();
 904         spin_lock_irqsave(&sclp_lock, flags);
 905         if (rc) {
 906                 sclp_init_state = sclp_init_state_uninitialized;
 907                 spin_unlock_irqrestore(&sclp_lock, flags);
 908                 return rc;
 909         }
 910         /* Register reboot handler */
 911         rc = register_reboot_notifier(&sclp_reboot_notifier);
 912         if (rc) {
 913                 sclp_init_state = sclp_init_state_uninitialized;
 914                 spin_unlock_irqrestore(&sclp_lock, flags);
 915                 return rc;
 916         }
 917         /* Register interrupt handler */
 918         rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler,
 919                                                &ext_int_info_hwc);
 920         if (rc) {
 921                 unregister_reboot_notifier(&sclp_reboot_notifier);
 922                 sclp_init_state = sclp_init_state_uninitialized;
 923                 spin_unlock_irqrestore(&sclp_lock, flags);
 924                 return rc;
 925         }
 926         sclp_init_state = sclp_init_state_initialized;
 927         spin_unlock_irqrestore(&sclp_lock, flags);
 928         /* Enable service-signal external interruption - needs to happen with
 929          * IRQs enabled. */
 930         ctl_set_bit(0, 9);
 931         sclp_init_mask(1);
 932         return 0;
 933 }