kernel/time/alarmtimer.c

   1 /*
   2  * Alarmtimer interface
   3  *
   4  * This interface provides a timer which is similarto hrtimers,
   5  * but triggers a RTC alarm if the box is suspend.
   6  *
   7  * This interface is influenced by the Android RTC Alarm timer
   8  * interface.
   9  *
  10  * Copyright (C) 2010 IBM Corperation
  11  *
  12  * Author: John Stultz <john.stultz@linaro.org>
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License version 2 as
  16  * published by the Free Software Foundation.
  17  */
  18 #include <linux/time.h>
  19 #include <linux/hrtimer.h>
  20 #include <linux/timerqueue.h>
  21 #include <linux/rtc.h>
  22 #include <linux/alarmtimer.h>
  23 #include <linux/mutex.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/posix-timers.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/freezer.h>
  28
  29 /**
  30  * struct alarm_base - Alarm timer bases
  31  * @lock:               Lock for syncrhonized access to the base
  32  * @timerqueue:         Timerqueue head managing the list of events
  33  * @timer:              hrtimer used to schedule events while running
  34  * @gettime:            Function to read the time correlating to the base
  35  * @base_clockid:       clockid for the base
  36  */
  37 static struct alarm_base {
  38         spinlock_t              lock;
  39         struct timerqueue_head  timerqueue;
  40         struct hrtimer          timer;
  41         ktime_t                 (*gettime)(void);
  42         clockid_t               base_clockid;
  43 } alarm_bases[ALARM_NUMTYPE];
  44
  45 /* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
  46 static ktime_t freezer_delta;
  47 static DEFINE_SPINLOCK(freezer_delta_lock);
  48
  49 #ifdef CONFIG_RTC_CLASS
  50 /* rtc timer and device for setting alarm wakeups at suspend */
  51 static struct rtc_timer         rtctimer;
  52 static struct rtc_device        *rtcdev;
  53 static DEFINE_SPINLOCK(rtcdev_lock);
  54
  55 /**
  56  * has_wakealarm - check rtc device has wakealarm ability
  57  * @dev: current device
  58  * @name_ptr: name to be returned
  59  *
  60  * This helper function checks to see if the rtc device can wake
  61  * from suspend.
  62  */
  63 static int has_wakealarm(struct device *dev, void *name_ptr)
  64 {
  65         struct rtc_device *candidate = to_rtc_device(dev);
  66
  67         if (!candidate->ops->set_alarm)
  68                 return 0;
  69         if (!device_may_wakeup(candidate->dev.parent))
  70                 return 0;
  71
  72         *(const char **)name_ptr = dev_name(dev);
  73         return 1;
  74 }
  75
  76 /**
  77  * alarmtimer_get_rtcdev - Return selected rtcdevice
  78  *
  79  * This function returns the rtc device to use for wakealarms.
  80  * If one has not already been chosen, it checks to see if a
  81  * functional rtc device is available.
  82  */
  83 static struct rtc_device *alarmtimer_get_rtcdev(void)
  84 {
  85         struct device *dev;
  86         char *str;
  87         unsigned long flags;
  88         struct rtc_device *ret;
  89
  90         spin_lock_irqsave(&rtcdev_lock, flags);
  91         if (!rtcdev) {
  92                 /* Find an rtc device and init the rtc_timer */
  93                 dev = class_find_device(rtc_class, NULL, &str, has_wakealarm);
  94                 /* If we have a device then str is valid. See has_wakealarm() */
  95                 if (dev) {
  96                         rtcdev = rtc_class_open(str);
  97                         /*
  98                          * Drop the reference we got in class_find_device,
  99                          * rtc_open takes its own.
 100                          */
 101                         put_device(dev);
 102                         rtc_timer_init(&rtctimer, NULL, NULL);
 103                 }
 104         }
 105         ret = rtcdev;
 106         spin_unlock_irqrestore(&rtcdev_lock, flags);
 107
 108         return ret;
 109 }
 110 #else
 111 #define alarmtimer_get_rtcdev() (0)
 112 #define rtcdev (0)
 113 #endif
 114
 115
 116 /**
 117  * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
 118  * @base: pointer to the base where the timer is being run
 119  * @alarm: pointer to alarm being enqueued.
 120  *
 121  * Adds alarm to a alarm_base timerqueue and if necessary sets
 122  * an hrtimer to run.
 123  *
 124  * Must hold base->lock when calling.
 125  */
 126 static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
 127 {
 128         timerqueue_add(&base->timerqueue, &alarm->node);
 129         if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
 130                 hrtimer_try_to_cancel(&base->timer);
 131                 hrtimer_start(&base->timer, alarm->node.expires,
 132                                 HRTIMER_MODE_ABS);
 133         }
 134 }
 135
 136 /**
 137  * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
 138  * @base: pointer to the base where the timer is running
 139  * @alarm: pointer to alarm being removed
 140  *
 141  * Removes alarm to a alarm_base timerqueue and if necessary sets
 142  * a new timer to run.
 143  *
 144  * Must hold base->lock when calling.
 145  */
 146 static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
 147 {
 148         struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);
 149
 150         timerqueue_del(&base->timerqueue, &alarm->node);
 151         if (next == &alarm->node) {
 152                 hrtimer_try_to_cancel(&base->timer);
 153                 next = timerqueue_getnext(&base->timerqueue);
 154                 if (!next)
 155                         return;
 156                 hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);
 157         }
 158 }
 159
 160
 161 /**
 162  * alarmtimer_fired - Handles alarm hrtimer being fired.
 163  * @timer: pointer to hrtimer being run
 164  *
 165  * When a alarm timer fires, this runs through the timerqueue to
 166  * see which alarms expired, and runs those. If there are more alarm
 167  * timers queued for the future, we set the hrtimer to fire when
 168  * when the next future alarm timer expires.
 169  */
 170 static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
 171 {
 172         struct alarm_base *base = container_of(timer, struct alarm_base, timer);
 173         struct timerqueue_node *next;
 174         unsigned long flags;
 175         ktime_t now;
 176         int ret = HRTIMER_NORESTART;
 177         int restart = ALARMTIMER_NORESTART;
 178
 179         spin_lock_irqsave(&base->lock, flags);
 180         now = base->gettime();
 181         while ((next = timerqueue_getnext(&base->timerqueue))) {
 182                 struct alarm *alarm;
 183                 ktime_t expired = next->expires;
 184
 185                 if (expired.tv64 >= now.tv64)
 186                         break;
 187
 188                 alarm = container_of(next, struct alarm, node);
 189
 190                 timerqueue_del(&base->timerqueue, &alarm->node);
 191                 alarm->enabled = 0;
 192
 193                 spin_unlock_irqrestore(&base->lock, flags);
 194                 if (alarm->function)
 195                         restart = alarm->function(alarm, now);
 196                 spin_lock_irqsave(&base->lock, flags);
 197
 198                 if (restart != ALARMTIMER_NORESTART) {
 199                         timerqueue_add(&base->timerqueue, &alarm->node);
 200                         alarm->enabled = 1;
 201                 }
 202         }
 203
 204         if (next) {
 205                 hrtimer_set_expires(&base->timer, next->expires);
 206                 ret = HRTIMER_RESTART;
 207         }
 208         spin_unlock_irqrestore(&base->lock, flags);
 209
 210         return ret;
 211
 212 }
 213
 214 #ifdef CONFIG_RTC_CLASS
 215 /**
 216  * alarmtimer_suspend - Suspend time callback
 217  * @dev: unused
 218  * @state: unused
 219  *
 220  * When we are going into suspend, we look through the bases
 221  * to see which is the soonest timer to expire. We then
 222  * set an rtc timer to fire that far into the future, which
 223  * will wake us from suspend.
 224  */
 225 static int alarmtimer_suspend(struct device *dev)
 226 {
 227         struct rtc_time tm;
 228         ktime_t min, now;
 229         unsigned long flags;
 230         struct rtc_device *rtc;
 231         int i;
 232
 233         spin_lock_irqsave(&freezer_delta_lock, flags);
 234         min = freezer_delta;
 235         freezer_delta = ktime_set(0, 0);
 236         spin_unlock_irqrestore(&freezer_delta_lock, flags);
 237
 238         rtc = rtcdev;
 239         /* If we have no rtcdev, just return */
 240         if (!rtc)
 241                 return 0;
 242
 243         /* Find the soonest timer to expire*/
 244         for (i = 0; i < ALARM_NUMTYPE; i++) {
 245                 struct alarm_base *base = &alarm_bases[i];
 246                 struct timerqueue_node *next;
 247                 ktime_t delta;
 248
 249                 spin_lock_irqsave(&base->lock, flags);
 250                 next = timerqueue_getnext(&base->timerqueue);
 251                 spin_unlock_irqrestore(&base->lock, flags);
 252                 if (!next)
 253                         continue;
 254                 delta = ktime_sub(next->expires, base->gettime());
 255                 if (!min.tv64 || (delta.tv64 < min.tv64))
 256                         min = delta;
 257         }
 258         if (min.tv64 == 0)
 259                 return 0;
 260
 261         /* XXX - Should we enforce a minimum sleep time? */
 262         WARN_ON(min.tv64 < NSEC_PER_SEC);
 263
 264         /* Setup an rtc timer to fire that far in the future */
 265         rtc_timer_cancel(rtc, &rtctimer);
 266         rtc_read_time(rtc, &tm);
 267         now = rtc_tm_to_ktime(tm);
 268         now = ktime_add(now, min);
 269
 270         rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
 271
 272         return 0;
 273 }
 274 #else
 275 static int alarmtimer_suspend(struct device *dev)
 276 {
 277         return 0;
 278 }
 279 #endif
 280
 281 static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
 282 {
 283         ktime_t delta;
 284         unsigned long flags;
 285         struct alarm_base *base = &alarm_bases[type];
 286
 287         delta = ktime_sub(absexp, base->gettime());
 288
 289         spin_lock_irqsave(&freezer_delta_lock, flags);
 290         if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
 291                 freezer_delta = delta;
 292         spin_unlock_irqrestore(&freezer_delta_lock, flags);
 293 }
 294
 295
 296 /**
 297  * alarm_init - Initialize an alarm structure
 298  * @alarm: ptr to alarm to be initialized
 299  * @type: the type of the alarm
 300  * @function: callback that is run when the alarm fires
 301  */
 302 void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
 303                 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
 304 {
 305         timerqueue_init(&alarm->node);
 306         alarm->period = ktime_set(0, 0);
 307         alarm->function = function;
 308         alarm->type = type;
 309         alarm->enabled = 0;
 310 }
 311
 312 /**
 313  * alarm_start - Sets an alarm to fire
 314  * @alarm: ptr to alarm to set
 315  * @start: time to run the alarm
 316  * @period: period at which the alarm will recur
 317  */
 318 void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period)
 319 {
 320         struct alarm_base *base = &alarm_bases[alarm->type];
 321         unsigned long flags;
 322
 323         spin_lock_irqsave(&base->lock, flags);
 324         if (alarm->enabled)
 325                 alarmtimer_remove(base, alarm);
 326         alarm->node.expires = start;
 327         alarm->period = period;
 328         alarmtimer_enqueue(base, alarm);
 329         alarm->enabled = 1;
 330         spin_unlock_irqrestore(&base->lock, flags);
 331 }
 332
 333 /**
 334  * alarm_cancel - Tries to cancel an alarm timer
 335  * @alarm: ptr to alarm to be canceled
 336  */
 337 void alarm_cancel(struct alarm *alarm)
 338 {
 339         struct alarm_base *base = &alarm_bases[alarm->type];
 340         unsigned long flags;
 341
 342         spin_lock_irqsave(&base->lock, flags);
 343         if (alarm->enabled)
 344                 alarmtimer_remove(base, alarm);
 345         alarm->enabled = 0;
 346         spin_unlock_irqrestore(&base->lock, flags);
 347 }
 348
 349
 350
 351 u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
 352 {
 353         u64 overrun = 1;
 354         ktime_t delta;
 355
 356         delta = ktime_sub(now, alarm->node.expires);
 357
 358         if (delta.tv64 < 0)
 359                 return 0;
 360
 361         if (unlikely(delta.tv64 >= interval.tv64)) {
 362                 s64 incr = ktime_to_ns(interval);
 363
 364                 overrun = ktime_divns(delta, incr);
 365
 366                 alarm->node.expires = ktime_add_ns(alarm->node.expires,
 367                                                         incr*overrun);
 368
 369                 if (alarm->node.expires.tv64 > now.tv64)
 370                         return overrun;
 371                 /*
 372                  * This (and the ktime_add() below) is the
 373                  * correction for exact:
 374                  */
 375                 overrun++;
 376         }
 377
 378         alarm->node.expires = ktime_add(alarm->node.expires, interval);
 379         return overrun;
 380 }
 381
 382
 383
 384
 385 /**
 386  * clock2alarm - helper that converts from clockid to alarmtypes
 387  * @clockid: clockid.
 388  */
 389 static enum alarmtimer_type clock2alarm(clockid_t clockid)
 390 {
 391         if (clockid == CLOCK_REALTIME_ALARM)
 392                 return ALARM_REALTIME;
 393         if (clockid == CLOCK_BOOTTIME_ALARM)
 394                 return ALARM_BOOTTIME;
 395         return -1;
 396 }
 397
 398 /**
 399  * alarm_handle_timer - Callback for posix timers
 400  * @alarm: alarm that fired
 401  *
 402  * Posix timer callback for expired alarm timers.
 403  */
 404 static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
 405                                                         ktime_t now)
 406 {
 407         struct k_itimer *ptr = container_of(alarm, struct k_itimer,
 408                                                 it.alarmtimer);
 409         if (posix_timer_event(ptr, 0) != 0)
 410                 ptr->it_overrun++;
 411
 412         /* Re-add periodic timers */
 413         if (alarm->period.tv64) {
 414                 ptr->it_overrun += alarm_forward(alarm, now, alarm->period);
 415                 return ALARMTIMER_RESTART;
 416         }
 417         return ALARMTIMER_NORESTART;
 418 }
 419
 420 /**
 421  * alarm_clock_getres - posix getres interface
 422  * @which_clock: clockid
 423  * @tp: timespec to fill
 424  *
 425  * Returns the granularity of underlying alarm base clock
 426  */
 427 static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
 428 {
 429         clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
 430
 431         if (!alarmtimer_get_rtcdev())
 432                 return -ENOTSUPP;
 433
 434         return hrtimer_get_res(baseid, tp);
 435 }
 436
 437 /**
 438  * alarm_clock_get - posix clock_get interface
 439  * @which_clock: clockid
 440  * @tp: timespec to fill.
 441  *
 442  * Provides the underlying alarm base time.
 443  */
 444 static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
 445 {
 446         struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
 447
 448         if (!alarmtimer_get_rtcdev())
 449                 return -ENOTSUPP;
 450
 451         *tp = ktime_to_timespec(base->gettime());
 452         return 0;
 453 }
 454
 455 /**
 456  * alarm_timer_create - posix timer_create interface
 457  * @new_timer: k_itimer pointer to manage
 458  *
 459  * Initializes the k_itimer structure.
 460  */
 461 static int alarm_timer_create(struct k_itimer *new_timer)
 462 {
 463         enum  alarmtimer_type type;
 464         struct alarm_base *base;
 465
 466         if (!alarmtimer_get_rtcdev())
 467                 return -ENOTSUPP;
 468
 469         if (!capable(CAP_WAKE_ALARM))
 470                 return -EPERM;
 471
 472         type = clock2alarm(new_timer->it_clock);
 473         base = &alarm_bases[type];
 474         alarm_init(&new_timer->it.alarmtimer, type, alarm_handle_timer);
 475         return 0;
 476 }
 477
 478 /**
 479  * alarm_timer_get - posix timer_get interface
 480  * @new_timer: k_itimer pointer
 481  * @cur_setting: itimerspec data to fill
 482  *
 483  * Copies the itimerspec data out from the k_itimer
 484  */
 485 static void alarm_timer_get(struct k_itimer *timr,
 486                                 struct itimerspec *cur_setting)
 487 {
 488         memset(cur_setting, 0, sizeof(struct itimerspec));
 489
 490         cur_setting->it_interval =
 491                         ktime_to_timespec(timr->it.alarmtimer.period);
 492         cur_setting->it_value =
 493                         ktime_to_timespec(timr->it.alarmtimer.node.expires);
 494         return;
 495 }
 496
 497 /**
 498  * alarm_timer_del - posix timer_del interface
 499  * @timr: k_itimer pointer to be deleted
 500  *
 501  * Cancels any programmed alarms for the given timer.
 502  */
 503 static int alarm_timer_del(struct k_itimer *timr)
 504 {
 505         if (!rtcdev)
 506                 return -ENOTSUPP;
 507
 508         alarm_cancel(&timr->it.alarmtimer);
 509         return 0;
 510 }
 511
 512 /**
 513  * alarm_timer_set - posix timer_set interface
 514  * @timr: k_itimer pointer to be deleted
 515  * @flags: timer flags
 516  * @new_setting: itimerspec to be used
 517  * @old_setting: itimerspec being replaced
 518  *
 519  * Sets the timer to new_setting, and starts the timer.
 520  */
 521 static int alarm_timer_set(struct k_itimer *timr, int flags,
 522                                 struct itimerspec *new_setting,
 523                                 struct itimerspec *old_setting)
 524 {
 525         if (!rtcdev)
 526                 return -ENOTSUPP;
 527
 528         if (old_setting)
 529                 alarm_timer_get(timr, old_setting);
 530
 531         /* If the timer was already set, cancel it */
 532         alarm_cancel(&timr->it.alarmtimer);
 533
 534         /* start the timer */
 535         alarm_start(&timr->it.alarmtimer,
 536                         timespec_to_ktime(new_setting->it_value),
 537                         timespec_to_ktime(new_setting->it_interval));
 538         return 0;
 539 }
 540
 541 /**
 542  * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
 543  * @alarm: ptr to alarm that fired
 544  *
 545  * Wakes up the task that set the alarmtimer
 546  */
 547 static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
 548                                                                 ktime_t now)
 549 {
 550         struct task_struct *task = (struct task_struct *)alarm->data;
 551
 552         alarm->data = NULL;
 553         if (task)
 554                 wake_up_process(task);
 555         return ALARMTIMER_NORESTART;
 556 }
 557
 558 /**
 559  * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
 560  * @alarm: ptr to alarmtimer
 561  * @absexp: absolute expiration time
 562  *
 563  * Sets the alarm timer and sleeps until it is fired or interrupted.
 564  */
 565 static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
 566 {
 567         alarm->data = (void *)current;
 568         do {
 569                 set_current_state(TASK_INTERRUPTIBLE);
 570                 alarm_start(alarm, absexp, ktime_set(0, 0));
 571                 if (likely(alarm->data))
 572                         schedule();
 573
 574                 alarm_cancel(alarm);
 575         } while (alarm->data && !signal_pending(current));
 576
 577         __set_current_state(TASK_RUNNING);
 578
 579         return (alarm->data == NULL);
 580 }
 581
 582
 583 /**
 584  * update_rmtp - Update remaining timespec value
 585  * @exp: expiration time
 586  * @type: timer type
 587  * @rmtp: user pointer to remaining timepsec value
 588  *
 589  * Helper function that fills in rmtp value with time between
 590  * now and the exp value
 591  */
 592 static int update_rmtp(ktime_t exp, enum  alarmtimer_type type,
 593                         struct timespec __user *rmtp)
 594 {
 595         struct timespec rmt;
 596         ktime_t rem;
 597
 598         rem = ktime_sub(exp, alarm_bases[type].gettime());
 599
 600         if (rem.tv64 <= 0)
 601                 return 0;
 602         rmt = ktime_to_timespec(rem);
 603
 604         if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
 605                 return -EFAULT;
 606
 607         return 1;
 608
 609 }
 610
 611 /**
 612  * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
 613  * @restart: ptr to restart block
 614  *
 615  * Handles restarted clock_nanosleep calls
 616  */
 617 static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
 618 {
 619         enum  alarmtimer_type type = restart->nanosleep.clockid;
 620         ktime_t exp;
 621         struct timespec __user  *rmtp;
 622         struct alarm alarm;
 623         int ret = 0;
 624
 625         exp.tv64 = restart->nanosleep.expires;
 626         alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
 627
 628         if (alarmtimer_do_nsleep(&alarm, exp))
 629                 goto out;
 630
 631         if (freezing(current))
 632                 alarmtimer_freezerset(exp, type);
 633
 634         rmtp = restart->nanosleep.rmtp;
 635         if (rmtp) {
 636                 ret = update_rmtp(exp, type, rmtp);
 637                 if (ret <= 0)
 638                         goto out;
 639         }
 640
 641
 642         /* The other values in restart are already filled in */
 643         ret = -ERESTART_RESTARTBLOCK;
 644 out:
 645         return ret;
 646 }
 647
 648 /**
 649  * alarm_timer_nsleep - alarmtimer nanosleep
 650  * @which_clock: clockid
 651  * @flags: determins abstime or relative
 652  * @tsreq: requested sleep time (abs or rel)
 653  * @rmtp: remaining sleep time saved
 654  *
 655  * Handles clock_nanosleep calls against _ALARM clockids
 656  */
 657 static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
 658                      struct timespec *tsreq, struct timespec __user *rmtp)
 659 {
 660         enum  alarmtimer_type type = clock2alarm(which_clock);
 661         struct alarm alarm;
 662         ktime_t exp;
 663         int ret = 0;
 664         struct restart_block *restart;
 665
 666         if (!alarmtimer_get_rtcdev())
 667                 return -ENOTSUPP;
 668
 669         if (!capable(CAP_WAKE_ALARM))
 670                 return -EPERM;
 671
 672         alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
 673
 674         exp = timespec_to_ktime(*tsreq);
 675         /* Convert (if necessary) to absolute time */
 676         if (flags != TIMER_ABSTIME) {
 677                 ktime_t now = alarm_bases[type].gettime();
 678                 exp = ktime_add(now, exp);
 679         }
 680
 681         if (alarmtimer_do_nsleep(&alarm, exp))
 682                 goto out;
 683
 684         if (freezing(current))
 685                 alarmtimer_freezerset(exp, type);
 686
 687         /* abs timers don't set remaining time or restart */
 688         if (flags == TIMER_ABSTIME) {
 689                 ret = -ERESTARTNOHAND;
 690                 goto out;
 691         }
 692
 693         if (rmtp) {
 694                 ret = update_rmtp(exp, type, rmtp);
 695                 if (ret <= 0)
 696                         goto out;
 697         }
 698
 699         restart = &current_thread_info()->restart_block;
 700         restart->fn = alarm_timer_nsleep_restart;
 701         restart->nanosleep.clockid = type;
 702         restart->nanosleep.expires = exp.tv64;
 703         restart->nanosleep.rmtp = rmtp;
 704         ret = -ERESTART_RESTARTBLOCK;
 705
 706 out:
 707         return ret;
 708 }
 709
 710
 711 /* Suspend hook structures */
 712 static const struct dev_pm_ops alarmtimer_pm_ops = {
 713         .suspend = alarmtimer_suspend,
 714 };
 715
 716 static struct platform_driver alarmtimer_driver = {
 717         .driver = {
 718                 .name = "alarmtimer",
 719                 .pm = &alarmtimer_pm_ops,
 720         }
 721 };
 722
 723 /**
 724  * alarmtimer_init - Initialize alarm timer code
 725  *
 726  * This function initializes the alarm bases and registers
 727  * the posix clock ids.
 728  */
 729 static int __init alarmtimer_init(void)
 730 {
 731         int error = 0;
 732         int i;
 733         struct k_clock alarm_clock = {
 734                 .clock_getres   = alarm_clock_getres,
 735                 .clock_get      = alarm_clock_get,
 736                 .timer_create   = alarm_timer_create,
 737                 .timer_set      = alarm_timer_set,
 738                 .timer_del      = alarm_timer_del,
 739                 .timer_get      = alarm_timer_get,
 740                 .nsleep         = alarm_timer_nsleep,
 741         };
 742
 743         posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
 744         posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
 745
 746         /* Initialize alarm bases */
 747         alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
 748         alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
 749         alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
 750         alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
 751         for (i = 0; i < ALARM_NUMTYPE; i++) {
 752                 timerqueue_init_head(&alarm_bases[i].timerqueue);
 753                 spin_lock_init(&alarm_bases[i].lock);
 754                 hrtimer_init(&alarm_bases[i].timer,
 755                                 alarm_bases[i].base_clockid,
 756                                 HRTIMER_MODE_ABS);
 757                 alarm_bases[i].timer.function = alarmtimer_fired;
 758         }
 759         error = platform_driver_register(&alarmtimer_driver);
 760         platform_device_register_simple("alarmtimer", -1, NULL, 0);
 761
 762         return error;
 763 }
 764 device_initcall(alarmtimer_init);
 765