drivers/s390/char/sclp.c

   1 /*
   2  * core function to access sclp interface
   3  *
   4  * Copyright IBM Corp. 1999, 2009
   5  *
   6  * Author(s): Martin Peschke <mpeschke@de.ibm.com>
   7  *            Martin Schwidefsky <schwidefsky@de.ibm.com>
   8  */
   9
  10 #include <linux/kernel_stat.h>
  11 #include <linux/module.h>
  12 #include <linux/err.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/timer.h>
  16 #include <linux/reboot.h>
  17 #include <linux/jiffies.h>
  18 #include <linux/init.h>
  19 #include <linux/suspend.h>
  20 #include <linux/completion.h>
  21 #include <linux/platform_device.h>
  22 #include <asm/types.h>
  23 #include <asm/irq.h>
  24
  25 #include "sclp.h"
  26
  27 #define SCLP_HEADER             "sclp: "
  28
  29 /* Lock to protect internal data consistency. */
  30 static DEFINE_SPINLOCK(sclp_lock);
  31
  32 /* Mask of events that we can send to the sclp interface. */
  33 static sccb_mask_t sclp_receive_mask;
  34
  35 /* Mask of events that we can receive from the sclp interface. */
  36 static sccb_mask_t sclp_send_mask;
  37
  38 /* List of registered event listeners and senders. */
  39 static struct list_head sclp_reg_list;
  40
  41 /* List of queued requests. */
  42 static struct list_head sclp_req_queue;
  43
  44 /* Data for read and and init requests. */
  45 static struct sclp_req sclp_read_req;
  46 static struct sclp_req sclp_init_req;
  47 static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  48 static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  49
  50 /* Suspend request */
  51 static DECLARE_COMPLETION(sclp_request_queue_flushed);
  52
  53 /* Number of console pages to allocate, used by sclp_con.c and sclp_vt220.c */
  54 int sclp_console_pages = SCLP_CONSOLE_PAGES;
  55 /* Flag to indicate if buffer pages are dropped on buffer full condition */
  56 int sclp_console_drop = 0;
  57 /* Number of times the console dropped buffer pages */
  58 unsigned long sclp_console_full;
  59
  60 static void sclp_suspend_req_cb(struct sclp_req *req, void *data)
  61 {
  62         complete(&sclp_request_queue_flushed);
  63 }
  64
  65 static int __init sclp_setup_console_pages(char *str)
  66 {
  67         int pages, rc;
  68
  69         rc = kstrtoint(str, 0, &pages);
  70         if (!rc && pages >= SCLP_CONSOLE_PAGES)
  71                 sclp_console_pages = pages;
  72         return 1;
  73 }
  74
  75 __setup("sclp_con_pages=", sclp_setup_console_pages);
  76
  77 static int __init sclp_setup_console_drop(char *str)
  78 {
  79         int drop, rc;
  80
  81         rc = kstrtoint(str, 0, &drop);
  82         if (!rc && drop)
  83                 sclp_console_drop = 1;
  84         return 1;
  85 }
  86
  87 __setup("sclp_con_drop=", sclp_setup_console_drop);
  88
  89 static struct sclp_req sclp_suspend_req;
  90
  91 /* Timer for request retries. */
  92 static struct timer_list sclp_request_timer;
  93
  94 /* Internal state: is the driver initialized? */
  95 static volatile enum sclp_init_state_t {
  96         sclp_init_state_uninitialized,
  97         sclp_init_state_initializing,
  98         sclp_init_state_initialized
  99 } sclp_init_state = sclp_init_state_uninitialized;
 100
 101 /* Internal state: is a request active at the sclp? */
 102 static volatile enum sclp_running_state_t {
 103         sclp_running_state_idle,
 104         sclp_running_state_running,
 105         sclp_running_state_reset_pending
 106 } sclp_running_state = sclp_running_state_idle;
 107
 108 /* Internal state: is a read request pending? */
 109 static volatile enum sclp_reading_state_t {
 110         sclp_reading_state_idle,
 111         sclp_reading_state_reading
 112 } sclp_reading_state = sclp_reading_state_idle;
 113
 114 /* Internal state: is the driver currently serving requests? */
 115 static volatile enum sclp_activation_state_t {
 116         sclp_activation_state_active,
 117         sclp_activation_state_deactivating,
 118         sclp_activation_state_inactive,
 119         sclp_activation_state_activating
 120 } sclp_activation_state = sclp_activation_state_active;
 121
 122 /* Internal state: is an init mask request pending? */
 123 static volatile enum sclp_mask_state_t {
 124         sclp_mask_state_idle,
 125         sclp_mask_state_initializing
 126 } sclp_mask_state = sclp_mask_state_idle;
 127
 128 /* Internal state: is the driver suspended? */
 129 static enum sclp_suspend_state_t {
 130         sclp_suspend_state_running,
 131         sclp_suspend_state_suspended,
 132 } sclp_suspend_state = sclp_suspend_state_running;
 133
 134 /* Maximum retry counts */
 135 #define SCLP_INIT_RETRY         3
 136 #define SCLP_MASK_RETRY         3
 137
 138 /* Timeout intervals in seconds.*/
 139 #define SCLP_BUSY_INTERVAL      10
 140 #define SCLP_RETRY_INTERVAL     30
 141
 142 static void sclp_process_queue(void);
 143 static void __sclp_make_read_req(void);
 144 static int sclp_init_mask(int calculate);
 145 static int sclp_init(void);
 146
 147 /* Perform service call. Return 0 on success, non-zero otherwise. */
 148 int
 149 sclp_service_call(sclp_cmdw_t command, void *sccb)
 150 {
 151         int cc = 4; /* Initialize for program check handling */
 152
 153         asm volatile(
 154                 "0:     .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
 155                 "1:     ipm     %0\n"
 156                 "       srl     %0,28\n"
 157                 "2:\n"
 158                 EX_TABLE(0b, 2b)
 159                 EX_TABLE(1b, 2b)
 160                 : "+&d" (cc) : "d" (command), "a" (__pa(sccb))
 161                 : "cc", "memory");
 162         if (cc == 4)
 163                 return -EINVAL;
 164         if (cc == 3)
 165                 return -EIO;
 166         if (cc == 2)
 167                 return -EBUSY;
 168         return 0;
 169 }
 170
 171
 172 static void
 173 __sclp_queue_read_req(void)
 174 {
 175         if (sclp_reading_state == sclp_reading_state_idle) {
 176                 sclp_reading_state = sclp_reading_state_reading;
 177                 __sclp_make_read_req();
 178                 /* Add request to head of queue */
 179                 list_add(&sclp_read_req.list, &sclp_req_queue);
 180         }
 181 }
 182
 183 /* Set up request retry timer. Called while sclp_lock is locked. */
 184 static inline void
 185 __sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
 186                          unsigned long data)
 187 {
 188         del_timer(&sclp_request_timer);
 189         sclp_request_timer.function = function;
 190         sclp_request_timer.data = data;
 191         sclp_request_timer.expires = jiffies + time;
 192         add_timer(&sclp_request_timer);
 193 }
 194
 195 /* Request timeout handler. Restart the request queue. If DATA is non-zero,
 196  * force restart of running request. */
 197 static void
 198 sclp_request_timeout(unsigned long data)
 199 {
 200         unsigned long flags;
 201
 202         spin_lock_irqsave(&sclp_lock, flags);
 203         if (data) {
 204                 if (sclp_running_state == sclp_running_state_running) {
 205                         /* Break running state and queue NOP read event request
 206                          * to get a defined interface state. */
 207                         __sclp_queue_read_req();
 208                         sclp_running_state = sclp_running_state_idle;
 209                 }
 210         } else {
 211                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 212                                          sclp_request_timeout, 0);
 213         }
 214         spin_unlock_irqrestore(&sclp_lock, flags);
 215         sclp_process_queue();
 216 }
 217
 218 /* Try to start a request. Return zero if the request was successfully
 219  * started or if it will be started at a later time. Return non-zero otherwise.
 220  * Called while sclp_lock is locked. */
 221 static int
 222 __sclp_start_request(struct sclp_req *req)
 223 {
 224         int rc;
 225
 226         if (sclp_running_state != sclp_running_state_idle)
 227                 return 0;
 228         del_timer(&sclp_request_timer);
 229         rc = sclp_service_call(req->command, req->sccb);
 230         req->start_count++;
 231
 232         if (rc == 0) {
 233                 /* Successfully started request */
 234                 req->status = SCLP_REQ_RUNNING;
 235                 sclp_running_state = sclp_running_state_running;
 236                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 237                                          sclp_request_timeout, 1);
 238                 return 0;
 239         } else if (rc == -EBUSY) {
 240                 /* Try again later */
 241                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 242                                          sclp_request_timeout, 0);
 243                 return 0;
 244         }
 245         /* Request failed */
 246         req->status = SCLP_REQ_FAILED;
 247         return rc;
 248 }
 249
 250 /* Try to start queued requests. */
 251 static void
 252 sclp_process_queue(void)
 253 {
 254         struct sclp_req *req;
 255         int rc;
 256         unsigned long flags;
 257
 258         spin_lock_irqsave(&sclp_lock, flags);
 259         if (sclp_running_state != sclp_running_state_idle) {
 260                 spin_unlock_irqrestore(&sclp_lock, flags);
 261                 return;
 262         }
 263         del_timer(&sclp_request_timer);
 264         while (!list_empty(&sclp_req_queue)) {
 265                 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
 266                 if (!req->sccb)
 267                         goto do_post;
 268                 rc = __sclp_start_request(req);
 269                 if (rc == 0)
 270                         break;
 271                 /* Request failed */
 272                 if (req->start_count > 1) {
 273                         /* Cannot abort already submitted request - could still
 274                          * be active at the SCLP */
 275                         __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 276                                                  sclp_request_timeout, 0);
 277                         break;
 278                 }
 279 do_post:
 280                 /* Post-processing for aborted request */
 281                 list_del(&req->list);
 282                 if (req->callback) {
 283                         spin_unlock_irqrestore(&sclp_lock, flags);
 284                         req->callback(req, req->callback_data);
 285                         spin_lock_irqsave(&sclp_lock, flags);
 286                 }
 287         }
 288         spin_unlock_irqrestore(&sclp_lock, flags);
 289 }
 290
 291 static int __sclp_can_add_request(struct sclp_req *req)
 292 {
 293         if (req == &sclp_suspend_req || req == &sclp_init_req)
 294                 return 1;
 295         if (sclp_suspend_state != sclp_suspend_state_running)
 296                 return 0;
 297         if (sclp_init_state != sclp_init_state_initialized)
 298                 return 0;
 299         if (sclp_activation_state != sclp_activation_state_active)
 300                 return 0;
 301         return 1;
 302 }
 303
 304 /* Queue a new request. Return zero on success, non-zero otherwise. */
 305 int
 306 sclp_add_request(struct sclp_req *req)
 307 {
 308         unsigned long flags;
 309         int rc;
 310
 311         spin_lock_irqsave(&sclp_lock, flags);
 312         if (!__sclp_can_add_request(req)) {
 313                 spin_unlock_irqrestore(&sclp_lock, flags);
 314                 return -EIO;
 315         }
 316         req->status = SCLP_REQ_QUEUED;
 317         req->start_count = 0;
 318         list_add_tail(&req->list, &sclp_req_queue);
 319         rc = 0;
 320         /* Start if request is first in list */
 321         if (sclp_running_state == sclp_running_state_idle &&
 322             req->list.prev == &sclp_req_queue) {
 323                 if (!req->sccb) {
 324                         list_del(&req->list);
 325                         rc = -ENODATA;
 326                         goto out;
 327                 }
 328                 rc = __sclp_start_request(req);
 329                 if (rc)
 330                         list_del(&req->list);
 331         }
 332 out:
 333         spin_unlock_irqrestore(&sclp_lock, flags);
 334         return rc;
 335 }
 336
 337 EXPORT_SYMBOL(sclp_add_request);
 338
 339 /* Dispatch events found in request buffer to registered listeners. Return 0
 340  * if all events were dispatched, non-zero otherwise. */
 341 static int
 342 sclp_dispatch_evbufs(struct sccb_header *sccb)
 343 {
 344         unsigned long flags;
 345         struct evbuf_header *evbuf;
 346         struct list_head *l;
 347         struct sclp_register *reg;
 348         int offset;
 349         int rc;
 350
 351         spin_lock_irqsave(&sclp_lock, flags);
 352         rc = 0;
 353         for (offset = sizeof(struct sccb_header); offset < sccb->length;
 354              offset += evbuf->length) {
 355                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 356                 /* Check for malformed hardware response */
 357                 if (evbuf->length == 0)
 358                         break;
 359                 /* Search for event handler */
 360                 reg = NULL;
 361                 list_for_each(l, &sclp_reg_list) {
 362                         reg = list_entry(l, struct sclp_register, list);
 363                         if (reg->receive_mask & (1 << (32 - evbuf->type)))
 364                                 break;
 365                         else
 366                                 reg = NULL;
 367                 }
 368                 if (reg && reg->receiver_fn) {
 369                         spin_unlock_irqrestore(&sclp_lock, flags);
 370                         reg->receiver_fn(evbuf);
 371                         spin_lock_irqsave(&sclp_lock, flags);
 372                 } else if (reg == NULL)
 373                         rc = -EOPNOTSUPP;
 374         }
 375         spin_unlock_irqrestore(&sclp_lock, flags);
 376         return rc;
 377 }
 378
 379 /* Read event data request callback. */
 380 static void
 381 sclp_read_cb(struct sclp_req *req, void *data)
 382 {
 383         unsigned long flags;
 384         struct sccb_header *sccb;
 385
 386         sccb = (struct sccb_header *) req->sccb;
 387         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 388             sccb->response_code == 0x220))
 389                 sclp_dispatch_evbufs(sccb);
 390         spin_lock_irqsave(&sclp_lock, flags);
 391         sclp_reading_state = sclp_reading_state_idle;
 392         spin_unlock_irqrestore(&sclp_lock, flags);
 393 }
 394
 395 /* Prepare read event data request. Called while sclp_lock is locked. */
 396 static void __sclp_make_read_req(void)
 397 {
 398         struct sccb_header *sccb;
 399
 400         sccb = (struct sccb_header *) sclp_read_sccb;
 401         clear_page(sccb);
 402         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 403         sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
 404         sclp_read_req.status = SCLP_REQ_QUEUED;
 405         sclp_read_req.start_count = 0;
 406         sclp_read_req.callback = sclp_read_cb;
 407         sclp_read_req.sccb = sccb;
 408         sccb->length = PAGE_SIZE;
 409         sccb->function_code = 0;
 410         sccb->control_mask[2] = 0x80;
 411 }
 412
 413 /* Search request list for request with matching sccb. Return request if found,
 414  * NULL otherwise. Called while sclp_lock is locked. */
 415 static inline struct sclp_req *
 416 __sclp_find_req(u32 sccb)
 417 {
 418         struct list_head *l;
 419         struct sclp_req *req;
 420
 421         list_for_each(l, &sclp_req_queue) {
 422                 req = list_entry(l, struct sclp_req, list);
 423                 if (sccb == (u32) (addr_t) req->sccb)
 424                                 return req;
 425         }
 426         return NULL;
 427 }
 428
 429 /* Handler for external interruption. Perform request post-processing.
 430  * Prepare read event data request if necessary. Start processing of next
 431  * request on queue. */
 432 static void sclp_interrupt_handler(struct ext_code ext_code,
 433                                    unsigned int param32, unsigned long param64)
 434 {
 435         struct sclp_req *req;
 436         u32 finished_sccb;
 437         u32 evbuf_pending;
 438
 439         inc_irq_stat(IRQEXT_SCP);
 440         spin_lock(&sclp_lock);
 441         finished_sccb = param32 & 0xfffffff8;
 442         evbuf_pending = param32 & 0x3;
 443         if (finished_sccb) {
 444                 del_timer(&sclp_request_timer);
 445                 sclp_running_state = sclp_running_state_reset_pending;
 446                 req = __sclp_find_req(finished_sccb);
 447                 if (req) {
 448                         /* Request post-processing */
 449                         list_del(&req->list);
 450                         req->status = SCLP_REQ_DONE;
 451                         if (req->callback) {
 452                                 spin_unlock(&sclp_lock);
 453                                 req->callback(req, req->callback_data);
 454                                 spin_lock(&sclp_lock);
 455                         }
 456                 }
 457                 sclp_running_state = sclp_running_state_idle;
 458         }
 459         if (evbuf_pending &&
 460             sclp_activation_state == sclp_activation_state_active)
 461                 __sclp_queue_read_req();
 462         spin_unlock(&sclp_lock);
 463         sclp_process_queue();
 464 }
 465
 466 /* Convert interval in jiffies to TOD ticks. */
 467 static inline u64
 468 sclp_tod_from_jiffies(unsigned long jiffies)
 469 {
 470         return (u64) (jiffies / HZ) << 32;
 471 }
 472
 473 /* Wait until a currently running request finished. Note: while this function
 474  * is running, no timers are served on the calling CPU. */
 475 void
 476 sclp_sync_wait(void)
 477 {
 478         unsigned long long old_tick;
 479         unsigned long flags;
 480         unsigned long cr0, cr0_sync;
 481         u64 timeout;
 482         int irq_context;
 483
 484         /* We'll be disabling timer interrupts, so we need a custom timeout
 485          * mechanism */
 486         timeout = 0;
 487         if (timer_pending(&sclp_request_timer)) {
 488                 /* Get timeout TOD value */
 489                 timeout = get_tod_clock_fast() +
 490                           sclp_tod_from_jiffies(sclp_request_timer.expires -
 491                                                 jiffies);
 492         }
 493         local_irq_save(flags);
 494         /* Prevent bottom half from executing once we force interrupts open */
 495         irq_context = in_interrupt();
 496         if (!irq_context)
 497                 local_bh_disable();
 498         /* Enable service-signal interruption, disable timer interrupts */
 499         old_tick = local_tick_disable();
 500         trace_hardirqs_on();
 501         __ctl_store(cr0, 0, 0);
 502         cr0_sync = cr0;
 503         cr0_sync &= 0xffff00a0;
 504         cr0_sync |= 0x00000200;
 505         __ctl_load(cr0_sync, 0, 0);
 506         __arch_local_irq_stosm(0x01);
 507         /* Loop until driver state indicates finished request */
 508         while (sclp_running_state != sclp_running_state_idle) {
 509                 /* Check for expired request timer */
 510                 if (timer_pending(&sclp_request_timer) &&
 511                     get_tod_clock_fast() > timeout &&
 512                     del_timer(&sclp_request_timer))
 513                         sclp_request_timer.function(sclp_request_timer.data);
 514                 cpu_relax();
 515         }
 516         local_irq_disable();
 517         __ctl_load(cr0, 0, 0);
 518         if (!irq_context)
 519                 _local_bh_enable();
 520         local_tick_enable(old_tick);
 521         local_irq_restore(flags);
 522 }
 523 EXPORT_SYMBOL(sclp_sync_wait);
 524
 525 /* Dispatch changes in send and receive mask to registered listeners. */
 526 static void
 527 sclp_dispatch_state_change(void)
 528 {
 529         struct list_head *l;
 530         struct sclp_register *reg;
 531         unsigned long flags;
 532         sccb_mask_t receive_mask;
 533         sccb_mask_t send_mask;
 534
 535         do {
 536                 spin_lock_irqsave(&sclp_lock, flags);
 537                 reg = NULL;
 538                 list_for_each(l, &sclp_reg_list) {
 539                         reg = list_entry(l, struct sclp_register, list);
 540                         receive_mask = reg->send_mask & sclp_receive_mask;
 541                         send_mask = reg->receive_mask & sclp_send_mask;
 542                         if (reg->sclp_receive_mask != receive_mask ||
 543                             reg->sclp_send_mask != send_mask) {
 544                                 reg->sclp_receive_mask = receive_mask;
 545                                 reg->sclp_send_mask = send_mask;
 546                                 break;
 547                         } else
 548                                 reg = NULL;
 549                 }
 550                 spin_unlock_irqrestore(&sclp_lock, flags);
 551                 if (reg && reg->state_change_fn)
 552                         reg->state_change_fn(reg);
 553         } while (reg);
 554 }
 555
 556 struct sclp_statechangebuf {
 557         struct evbuf_header     header;
 558         u8              validity_sclp_active_facility_mask : 1;
 559         u8              validity_sclp_receive_mask : 1;
 560         u8              validity_sclp_send_mask : 1;
 561         u8              validity_read_data_function_mask : 1;
 562         u16             _zeros : 12;
 563         u16             mask_length;
 564         u64             sclp_active_facility_mask;
 565         sccb_mask_t     sclp_receive_mask;
 566         sccb_mask_t     sclp_send_mask;
 567         u32             read_data_function_mask;
 568 } __attribute__((packed));
 569
 570
 571 /* State change event callback. Inform listeners of changes. */
 572 static void
 573 sclp_state_change_cb(struct evbuf_header *evbuf)
 574 {
 575         unsigned long flags;
 576         struct sclp_statechangebuf *scbuf;
 577
 578         scbuf = (struct sclp_statechangebuf *) evbuf;
 579         if (scbuf->mask_length != sizeof(sccb_mask_t))
 580                 return;
 581         spin_lock_irqsave(&sclp_lock, flags);
 582         if (scbuf->validity_sclp_receive_mask)
 583                 sclp_receive_mask = scbuf->sclp_receive_mask;
 584         if (scbuf->validity_sclp_send_mask)
 585                 sclp_send_mask = scbuf->sclp_send_mask;
 586         spin_unlock_irqrestore(&sclp_lock, flags);
 587         if (scbuf->validity_sclp_active_facility_mask)
 588                 sclp_facilities = scbuf->sclp_active_facility_mask;
 589         sclp_dispatch_state_change();
 590 }
 591
 592 static struct sclp_register sclp_state_change_event = {
 593         .receive_mask = EVTYP_STATECHANGE_MASK,
 594         .receiver_fn = sclp_state_change_cb
 595 };
 596
 597 /* Calculate receive and send mask of currently registered listeners.
 598  * Called while sclp_lock is locked. */
 599 static inline void
 600 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 601 {
 602         struct list_head *l;
 603         struct sclp_register *t;
 604
 605         *receive_mask = 0;
 606         *send_mask = 0;
 607         list_for_each(l, &sclp_reg_list) {
 608                 t = list_entry(l, struct sclp_register, list);
 609                 *receive_mask |= t->receive_mask;
 610                 *send_mask |= t->send_mask;
 611         }
 612 }
 613
 614 /* Register event listener. Return 0 on success, non-zero otherwise. */
 615 int
 616 sclp_register(struct sclp_register *reg)
 617 {
 618         unsigned long flags;
 619         sccb_mask_t receive_mask;
 620         sccb_mask_t send_mask;
 621         int rc;
 622
 623         rc = sclp_init();
 624         if (rc)
 625                 return rc;
 626         spin_lock_irqsave(&sclp_lock, flags);
 627         /* Check event mask for collisions */
 628         __sclp_get_mask(&receive_mask, &send_mask);
 629         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 630                 spin_unlock_irqrestore(&sclp_lock, flags);
 631                 return -EBUSY;
 632         }
 633         /* Trigger initial state change callback */
 634         reg->sclp_receive_mask = 0;
 635         reg->sclp_send_mask = 0;
 636         reg->pm_event_posted = 0;
 637         list_add(&reg->list, &sclp_reg_list);
 638         spin_unlock_irqrestore(&sclp_lock, flags);
 639         rc = sclp_init_mask(1);
 640         if (rc) {
 641                 spin_lock_irqsave(&sclp_lock, flags);
 642                 list_del(&reg->list);
 643                 spin_unlock_irqrestore(&sclp_lock, flags);
 644         }
 645         return rc;
 646 }
 647
 648 EXPORT_SYMBOL(sclp_register);
 649
 650 /* Unregister event listener. */
 651 void
 652 sclp_unregister(struct sclp_register *reg)
 653 {
 654         unsigned long flags;
 655
 656         spin_lock_irqsave(&sclp_lock, flags);
 657         list_del(&reg->list);
 658         spin_unlock_irqrestore(&sclp_lock, flags);
 659         sclp_init_mask(1);
 660 }
 661
 662 EXPORT_SYMBOL(sclp_unregister);
 663
 664 /* Remove event buffers which are marked processed. Return the number of
 665  * remaining event buffers. */
 666 int
 667 sclp_remove_processed(struct sccb_header *sccb)
 668 {
 669         struct evbuf_header *evbuf;
 670         int unprocessed;
 671         u16 remaining;
 672
 673         evbuf = (struct evbuf_header *) (sccb + 1);
 674         unprocessed = 0;
 675         remaining = sccb->length - sizeof(struct sccb_header);
 676         while (remaining > 0) {
 677                 remaining -= evbuf->length;
 678                 if (evbuf->flags & 0x80) {
 679                         sccb->length -= evbuf->length;
 680                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 681                                remaining);
 682                 } else {
 683                         unprocessed++;
 684                         evbuf = (struct evbuf_header *)
 685                                         ((addr_t) evbuf + evbuf->length);
 686                 }
 687         }
 688         return unprocessed;
 689 }
 690
 691 EXPORT_SYMBOL(sclp_remove_processed);
 692
 693 /* Prepare init mask request. Called while sclp_lock is locked. */
 694 static inline void
 695 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
 696 {
 697         struct init_sccb *sccb;
 698
 699         sccb = (struct init_sccb *) sclp_init_sccb;
 700         clear_page(sccb);
 701         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 702         sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 703         sclp_init_req.status = SCLP_REQ_FILLED;
 704         sclp_init_req.start_count = 0;
 705         sclp_init_req.callback = NULL;
 706         sclp_init_req.callback_data = NULL;
 707         sclp_init_req.sccb = sccb;
 708         sccb->header.length = sizeof(struct init_sccb);
 709         sccb->mask_length = sizeof(sccb_mask_t);
 710         sccb->receive_mask = receive_mask;
 711         sccb->send_mask = send_mask;
 712         sccb->sclp_receive_mask = 0;
 713         sccb->sclp_send_mask = 0;
 714 }
 715
 716 /* Start init mask request. If calculate is non-zero, calculate the mask as
 717  * requested by registered listeners. Use zero mask otherwise. Return 0 on
 718  * success, non-zero otherwise. */
 719 static int
 720 sclp_init_mask(int calculate)
 721 {
 722         unsigned long flags;
 723         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
 724         sccb_mask_t receive_mask;
 725         sccb_mask_t send_mask;
 726         int retry;
 727         int rc;
 728         unsigned long wait;
 729
 730         spin_lock_irqsave(&sclp_lock, flags);
 731         /* Check if interface is in appropriate state */
 732         if (sclp_mask_state != sclp_mask_state_idle) {
 733                 spin_unlock_irqrestore(&sclp_lock, flags);
 734                 return -EBUSY;
 735         }
 736         if (sclp_activation_state == sclp_activation_state_inactive) {
 737                 spin_unlock_irqrestore(&sclp_lock, flags);
 738                 return -EINVAL;
 739         }
 740         sclp_mask_state = sclp_mask_state_initializing;
 741         /* Determine mask */
 742         if (calculate)
 743                 __sclp_get_mask(&receive_mask, &send_mask);
 744         else {
 745                 receive_mask = 0;
 746                 send_mask = 0;
 747         }
 748         rc = -EIO;
 749         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
 750                 /* Prepare request */
 751                 __sclp_make_init_req(receive_mask, send_mask);
 752                 spin_unlock_irqrestore(&sclp_lock, flags);
 753                 if (sclp_add_request(&sclp_init_req)) {
 754                         /* Try again later */
 755                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
 756                         while (time_before(jiffies, wait))
 757                                 sclp_sync_wait();
 758                         spin_lock_irqsave(&sclp_lock, flags);
 759                         continue;
 760                 }
 761                 while (sclp_init_req.status != SCLP_REQ_DONE &&
 762                        sclp_init_req.status != SCLP_REQ_FAILED)
 763                         sclp_sync_wait();
 764                 spin_lock_irqsave(&sclp_lock, flags);
 765                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 766                     sccb->header.response_code == 0x20) {
 767                         /* Successful request */
 768                         if (calculate) {
 769                                 sclp_receive_mask = sccb->sclp_receive_mask;
 770                                 sclp_send_mask = sccb->sclp_send_mask;
 771                         } else {
 772                                 sclp_receive_mask = 0;
 773                                 sclp_send_mask = 0;
 774                         }
 775                         spin_unlock_irqrestore(&sclp_lock, flags);
 776                         sclp_dispatch_state_change();
 777                         spin_lock_irqsave(&sclp_lock, flags);
 778                         rc = 0;
 779                         break;
 780                 }
 781         }
 782         sclp_mask_state = sclp_mask_state_idle;
 783         spin_unlock_irqrestore(&sclp_lock, flags);
 784         return rc;
 785 }
 786
 787 /* Deactivate SCLP interface. On success, new requests will be rejected,
 788  * events will no longer be dispatched. Return 0 on success, non-zero
 789  * otherwise. */
 790 int
 791 sclp_deactivate(void)
 792 {
 793         unsigned long flags;
 794         int rc;
 795
 796         spin_lock_irqsave(&sclp_lock, flags);
 797         /* Deactivate can only be called when active */
 798         if (sclp_activation_state != sclp_activation_state_active) {
 799                 spin_unlock_irqrestore(&sclp_lock, flags);
 800                 return -EINVAL;
 801         }
 802         sclp_activation_state = sclp_activation_state_deactivating;
 803         spin_unlock_irqrestore(&sclp_lock, flags);
 804         rc = sclp_init_mask(0);
 805         spin_lock_irqsave(&sclp_lock, flags);
 806         if (rc == 0)
 807                 sclp_activation_state = sclp_activation_state_inactive;
 808         else
 809                 sclp_activation_state = sclp_activation_state_active;
 810         spin_unlock_irqrestore(&sclp_lock, flags);
 811         return rc;
 812 }
 813
 814 EXPORT_SYMBOL(sclp_deactivate);
 815
 816 /* Reactivate SCLP interface after sclp_deactivate. On success, new
 817  * requests will be accepted, events will be dispatched again. Return 0 on
 818  * success, non-zero otherwise. */
 819 int
 820 sclp_reactivate(void)
 821 {
 822         unsigned long flags;
 823         int rc;
 824
 825         spin_lock_irqsave(&sclp_lock, flags);
 826         /* Reactivate can only be called when inactive */
 827         if (sclp_activation_state != sclp_activation_state_inactive) {
 828                 spin_unlock_irqrestore(&sclp_lock, flags);
 829                 return -EINVAL;
 830         }
 831         sclp_activation_state = sclp_activation_state_activating;
 832         spin_unlock_irqrestore(&sclp_lock, flags);
 833         rc = sclp_init_mask(1);
 834         spin_lock_irqsave(&sclp_lock, flags);
 835         if (rc == 0)
 836                 sclp_activation_state = sclp_activation_state_active;
 837         else
 838                 sclp_activation_state = sclp_activation_state_inactive;
 839         spin_unlock_irqrestore(&sclp_lock, flags);
 840         return rc;
 841 }
 842
 843 EXPORT_SYMBOL(sclp_reactivate);
 844
 845 /* Handler for external interruption used during initialization. Modify
 846  * request state to done. */
 847 static void sclp_check_handler(struct ext_code ext_code,
 848                                unsigned int param32, unsigned long param64)
 849 {
 850         u32 finished_sccb;
 851
 852         inc_irq_stat(IRQEXT_SCP);
 853         finished_sccb = param32 & 0xfffffff8;
 854         /* Is this the interrupt we are waiting for? */
 855         if (finished_sccb == 0)
 856                 return;
 857         if (finished_sccb != (u32) (addr_t) sclp_init_sccb)
 858                 panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
 859                       finished_sccb);
 860         spin_lock(&sclp_lock);
 861         if (sclp_running_state == sclp_running_state_running) {
 862                 sclp_init_req.status = SCLP_REQ_DONE;
 863                 sclp_running_state = sclp_running_state_idle;
 864         }
 865         spin_unlock(&sclp_lock);
 866 }
 867
 868 /* Initial init mask request timed out. Modify request state to failed. */
 869 static void
 870 sclp_check_timeout(unsigned long data)
 871 {
 872         unsigned long flags;
 873
 874         spin_lock_irqsave(&sclp_lock, flags);
 875         if (sclp_running_state == sclp_running_state_running) {
 876                 sclp_init_req.status = SCLP_REQ_FAILED;
 877                 sclp_running_state = sclp_running_state_idle;
 878         }
 879         spin_unlock_irqrestore(&sclp_lock, flags);
 880 }
 881
 882 /* Perform a check of the SCLP interface. Return zero if the interface is
 883  * available and there are no pending requests from a previous instance.
 884  * Return non-zero otherwise. */
 885 static int
 886 sclp_check_interface(void)
 887 {
 888         struct init_sccb *sccb;
 889         unsigned long flags;
 890         int retry;
 891         int rc;
 892
 893         spin_lock_irqsave(&sclp_lock, flags);
 894         /* Prepare init mask command */
 895         rc = register_external_interrupt(0x2401, sclp_check_handler);
 896         if (rc) {
 897                 spin_unlock_irqrestore(&sclp_lock, flags);
 898                 return rc;
 899         }
 900         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
 901                 __sclp_make_init_req(0, 0);
 902                 sccb = (struct init_sccb *) sclp_init_req.sccb;
 903                 rc = sclp_service_call(sclp_init_req.command, sccb);
 904                 if (rc == -EIO)
 905                         break;
 906                 sclp_init_req.status = SCLP_REQ_RUNNING;
 907                 sclp_running_state = sclp_running_state_running;
 908                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 909                                          sclp_check_timeout, 0);
 910                 spin_unlock_irqrestore(&sclp_lock, flags);
 911                 /* Enable service-signal interruption - needs to happen
 912                  * with IRQs enabled. */
 913                 irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
 914                 /* Wait for signal from interrupt or timeout */
 915                 sclp_sync_wait();
 916                 /* Disable service-signal interruption - needs to happen
 917                  * with IRQs enabled. */
 918                 irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
 919                 spin_lock_irqsave(&sclp_lock, flags);
 920                 del_timer(&sclp_request_timer);
 921                 if (sclp_init_req.status == SCLP_REQ_DONE &&
 922                     sccb->header.response_code == 0x20) {
 923                         rc = 0;
 924                         break;
 925                 } else
 926                         rc = -EBUSY;
 927         }
 928         unregister_external_interrupt(0x2401, sclp_check_handler);
 929         spin_unlock_irqrestore(&sclp_lock, flags);
 930         return rc;
 931 }
 932
 933 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 934  * events from interfering with rebooted system. */
 935 static int
 936 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 937 {
 938         sclp_deactivate();
 939         return NOTIFY_DONE;
 940 }
 941
 942 static struct notifier_block sclp_reboot_notifier = {
 943         .notifier_call = sclp_reboot_event
 944 };
 945
 946 /*
 947  * Suspend/resume SCLP notifier implementation
 948  */
 949
 950 static void sclp_pm_event(enum sclp_pm_event sclp_pm_event, int rollback)
 951 {
 952         struct sclp_register *reg;
 953         unsigned long flags;
 954
 955         if (!rollback) {
 956                 spin_lock_irqsave(&sclp_lock, flags);
 957                 list_for_each_entry(reg, &sclp_reg_list, list)
 958                         reg->pm_event_posted = 0;
 959                 spin_unlock_irqrestore(&sclp_lock, flags);
 960         }
 961         do {
 962                 spin_lock_irqsave(&sclp_lock, flags);
 963                 list_for_each_entry(reg, &sclp_reg_list, list) {
 964                         if (rollback && reg->pm_event_posted)
 965                                 goto found;
 966                         if (!rollback && !reg->pm_event_posted)
 967                                 goto found;
 968                 }
 969                 spin_unlock_irqrestore(&sclp_lock, flags);
 970                 return;
 971 found:
 972                 spin_unlock_irqrestore(&sclp_lock, flags);
 973                 if (reg->pm_event_fn)
 974                         reg->pm_event_fn(reg, sclp_pm_event);
 975                 reg->pm_event_posted = rollback ? 0 : 1;
 976         } while (1);
 977 }
 978
 979 /*
 980  * Susend/resume callbacks for platform device
 981  */
 982
 983 static int sclp_freeze(struct device *dev)
 984 {
 985         unsigned long flags;
 986         int rc;
 987
 988         sclp_pm_event(SCLP_PM_EVENT_FREEZE, 0);
 989
 990         spin_lock_irqsave(&sclp_lock, flags);
 991         sclp_suspend_state = sclp_suspend_state_suspended;
 992         spin_unlock_irqrestore(&sclp_lock, flags);
 993
 994         /* Init supend data */
 995         memset(&sclp_suspend_req, 0, sizeof(sclp_suspend_req));
 996         sclp_suspend_req.callback = sclp_suspend_req_cb;
 997         sclp_suspend_req.status = SCLP_REQ_FILLED;
 998         init_completion(&sclp_request_queue_flushed);
 999
1000         rc = sclp_add_request(&sclp_suspend_req);
1001         if (rc == 0)
1002                 wait_for_completion(&sclp_request_queue_flushed);
1003         else if (rc != -ENODATA)
1004                 goto fail_thaw;
1005
1006         rc = sclp_deactivate();
1007         if (rc)
1008                 goto fail_thaw;
1009         return 0;
1010
1011 fail_thaw:
1012         spin_lock_irqsave(&sclp_lock, flags);
1013         sclp_suspend_state = sclp_suspend_state_running;
1014         spin_unlock_irqrestore(&sclp_lock, flags);
1015         sclp_pm_event(SCLP_PM_EVENT_THAW, 1);
1016         return rc;
1017 }
1018
1019 static int sclp_undo_suspend(enum sclp_pm_event event)
1020 {
1021         unsigned long flags;
1022         int rc;
1023
1024         rc = sclp_reactivate();
1025         if (rc)
1026                 return rc;
1027
1028         spin_lock_irqsave(&sclp_lock, flags);
1029         sclp_suspend_state = sclp_suspend_state_running;
1030         spin_unlock_irqrestore(&sclp_lock, flags);
1031
1032         sclp_pm_event(event, 0);
1033         return 0;
1034 }
1035
1036 static int sclp_thaw(struct device *dev)
1037 {
1038         return sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1039 }
1040
1041 static int sclp_restore(struct device *dev)
1042 {
1043         return sclp_undo_suspend(SCLP_PM_EVENT_RESTORE);
1044 }
1045
1046 static const struct dev_pm_ops sclp_pm_ops = {
1047         .freeze         = sclp_freeze,
1048         .thaw           = sclp_thaw,
1049         .restore        = sclp_restore,
1050 };
1051
1052 static ssize_t sclp_show_console_pages(struct device_driver *dev, char *buf)
1053 {
1054         return sprintf(buf, "%i\n", sclp_console_pages);
1055 }
1056
1057 static DRIVER_ATTR(con_pages, S_IRUSR, sclp_show_console_pages, NULL);
1058
1059 static ssize_t sclp_show_con_drop(struct device_driver *dev, char *buf)
1060 {
1061         return sprintf(buf, "%i\n", sclp_console_drop);
1062 }
1063
1064 static DRIVER_ATTR(con_drop, S_IRUSR, sclp_show_con_drop, NULL);
1065
1066 static ssize_t sclp_show_console_full(struct device_driver *dev, char *buf)
1067 {
1068         return sprintf(buf, "%lu\n", sclp_console_full);
1069 }
1070
1071 static DRIVER_ATTR(con_full, S_IRUSR, sclp_show_console_full, NULL);
1072
1073 static struct attribute *sclp_drv_attrs[] = {
1074         &driver_attr_con_pages.attr,
1075         &driver_attr_con_drop.attr,
1076         &driver_attr_con_full.attr,
1077         NULL,
1078 };
1079 static struct attribute_group sclp_drv_attr_group = {
1080         .attrs = sclp_drv_attrs,
1081 };
1082 static const struct attribute_group *sclp_drv_attr_groups[] = {
1083         &sclp_drv_attr_group,
1084         NULL,
1085 };
1086
1087 static struct platform_driver sclp_pdrv = {
1088         .driver = {
1089                 .name   = "sclp",
1090                 .owner  = THIS_MODULE,
1091                 .pm     = &sclp_pm_ops,
1092                 .groups = sclp_drv_attr_groups,
1093         },
1094 };
1095
1096 static struct platform_device *sclp_pdev;
1097
1098 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
1099  * otherwise. */
1100 static int
1101 sclp_init(void)
1102 {
1103         unsigned long flags;
1104         int rc = 0;
1105
1106         spin_lock_irqsave(&sclp_lock, flags);
1107         /* Check for previous or running initialization */
1108         if (sclp_init_state != sclp_init_state_uninitialized)
1109                 goto fail_unlock;
1110         sclp_init_state = sclp_init_state_initializing;
1111         /* Set up variables */
1112         INIT_LIST_HEAD(&sclp_req_queue);
1113         INIT_LIST_HEAD(&sclp_reg_list);
1114         list_add(&sclp_state_change_event.list, &sclp_reg_list);
1115         init_timer(&sclp_request_timer);
1116         /* Check interface */
1117         spin_unlock_irqrestore(&sclp_lock, flags);
1118         rc = sclp_check_interface();
1119         spin_lock_irqsave(&sclp_lock, flags);
1120         if (rc)
1121                 goto fail_init_state_uninitialized;
1122         /* Register reboot handler */
1123         rc = register_reboot_notifier(&sclp_reboot_notifier);
1124         if (rc)
1125                 goto fail_init_state_uninitialized;
1126         /* Register interrupt handler */
1127         rc = register_external_interrupt(0x2401, sclp_interrupt_handler);
1128         if (rc)
1129                 goto fail_unregister_reboot_notifier;
1130         sclp_init_state = sclp_init_state_initialized;
1131         spin_unlock_irqrestore(&sclp_lock, flags);
1132         /* Enable service-signal external interruption - needs to happen with
1133          * IRQs enabled. */
1134         irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1135         sclp_init_mask(1);
1136         return 0;
1137
1138 fail_unregister_reboot_notifier:
1139         unregister_reboot_notifier(&sclp_reboot_notifier);
1140 fail_init_state_uninitialized:
1141         sclp_init_state = sclp_init_state_uninitialized;
1142 fail_unlock:
1143         spin_unlock_irqrestore(&sclp_lock, flags);
1144         return rc;
1145 }
1146
1147 /*
1148  * SCLP panic notifier: If we are suspended, we thaw SCLP in order to be able
1149  * to print the panic message.
1150  */
1151 static int sclp_panic_notify(struct notifier_block *self,
1152                              unsigned long event, void *data)
1153 {
1154         if (sclp_suspend_state == sclp_suspend_state_suspended)
1155                 sclp_undo_suspend(SCLP_PM_EVENT_THAW);
1156         return NOTIFY_OK;
1157 }
1158
1159 static struct notifier_block sclp_on_panic_nb = {
1160         .notifier_call = sclp_panic_notify,
1161         .priority = SCLP_PANIC_PRIO,
1162 };
1163
1164 static __init int sclp_initcall(void)
1165 {
1166         int rc;
1167
1168         rc = platform_driver_register(&sclp_pdrv);
1169         if (rc)
1170                 return rc;
1171
1172         sclp_pdev = platform_device_register_simple("sclp", -1, NULL, 0);
1173         rc = PTR_RET(sclp_pdev);
1174         if (rc)
1175                 goto fail_platform_driver_unregister;
1176
1177         rc = atomic_notifier_chain_register(&panic_notifier_list,
1178                                             &sclp_on_panic_nb);
1179         if (rc)
1180                 goto fail_platform_device_unregister;
1181
1182         return sclp_init();
1183
1184 fail_platform_device_unregister:
1185         platform_device_unregister(sclp_pdev);
1186 fail_platform_driver_unregister:
1187         platform_driver_unregister(&sclp_pdrv);
1188         return rc;
1189 }
1190
1191 arch_initcall(sclp_initcall);