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         ktime_t                 (*gettime)(void);
  41         clockid_t               base_clockid;
  42 } alarm_bases[ALARM_NUMTYPE];
  43
  44 /* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
  45 static ktime_t freezer_delta;
  46 static DEFINE_SPINLOCK(freezer_delta_lock);
  47
  48 static struct wakeup_source *ws;
  49
  50 #ifdef CONFIG_RTC_CLASS
  51 /* rtc timer and device for setting alarm wakeups at suspend */
  52 static struct rtc_timer         rtctimer;
  53 static struct rtc_device        *rtcdev;
  54 static DEFINE_SPINLOCK(rtcdev_lock);
  55
  56 /**
  57  * alarmtimer_get_rtcdev - Return selected rtcdevice
  58  *
  59  * This function returns the rtc device to use for wakealarms.
  60  * If one has not already been chosen, it checks to see if a
  61  * functional rtc device is available.
  62  */
  63 struct rtc_device *alarmtimer_get_rtcdev(void)
  64 {
  65         unsigned long flags;
  66         struct rtc_device *ret;
  67
  68         spin_lock_irqsave(&rtcdev_lock, flags);
  69         ret = rtcdev;
  70         spin_unlock_irqrestore(&rtcdev_lock, flags);
  71
  72         return ret;
  73 }
  74
  75
  76 static int alarmtimer_rtc_add_device(struct device *dev,
  77                                 struct class_interface *class_intf)
  78 {
  79         unsigned long flags;
  80         struct rtc_device *rtc = to_rtc_device(dev);
  81
  82         if (rtcdev)
  83                 return -EBUSY;
  84
  85         if (!rtc->ops->set_alarm)
  86                 return -1;
  87         if (!device_may_wakeup(rtc->dev.parent))
  88                 return -1;
  89
  90         spin_lock_irqsave(&rtcdev_lock, flags);
  91         if (!rtcdev) {
  92                 rtcdev = rtc;
  93                 /* hold a reference so it doesn't go away */
  94                 get_device(dev);
  95         }
  96         spin_unlock_irqrestore(&rtcdev_lock, flags);
  97         return 0;
  98 }
  99
 100 static inline void alarmtimer_rtc_timer_init(void)
 101 {
 102         rtc_timer_init(&rtctimer, NULL, NULL);
 103 }
 104
 105 static struct class_interface alarmtimer_rtc_interface = {
 106         .add_dev = &alarmtimer_rtc_add_device,
 107 };
 108
 109 static int alarmtimer_rtc_interface_setup(void)
 110 {
 111         alarmtimer_rtc_interface.class = rtc_class;
 112         return class_interface_register(&alarmtimer_rtc_interface);
 113 }
 114 static void alarmtimer_rtc_interface_remove(void)
 115 {
 116         class_interface_unregister(&alarmtimer_rtc_interface);
 117 }
 118 #else
 119 struct rtc_device *alarmtimer_get_rtcdev(void)
 120 {
 121         return NULL;
 122 }
 123 #define rtcdev (NULL)
 124 static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
 125 static inline void alarmtimer_rtc_interface_remove(void) { }
 126 static inline void alarmtimer_rtc_timer_init(void) { }
 127 #endif
 128
 129 /**
 130  * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
 131  * @base: pointer to the base where the timer is being run
 132  * @alarm: pointer to alarm being enqueued.
 133  *
 134  * Adds alarm to a alarm_base timerqueue
 135  *
 136  * Must hold base->lock when calling.
 137  */
 138 static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
 139 {
 140         if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
 141                 timerqueue_del(&base->timerqueue, &alarm->node);
 142
 143         timerqueue_add(&base->timerqueue, &alarm->node);
 144         alarm->state |= ALARMTIMER_STATE_ENQUEUED;
 145 }
 146
 147 /**
 148  * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
 149  * @base: pointer to the base where the timer is running
 150  * @alarm: pointer to alarm being removed
 151  *
 152  * Removes alarm to a alarm_base timerqueue
 153  *
 154  * Must hold base->lock when calling.
 155  */
 156 static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
 157 {
 158         if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
 159                 return;
 160
 161         timerqueue_del(&base->timerqueue, &alarm->node);
 162         alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
 163 }
 164
 165
 166 /**
 167  * alarmtimer_fired - Handles alarm hrtimer being fired.
 168  * @timer: pointer to hrtimer being run
 169  *
 170  * When a alarm timer fires, this runs through the timerqueue to
 171  * see which alarms expired, and runs those. If there are more alarm
 172  * timers queued for the future, we set the hrtimer to fire when
 173  * when the next future alarm timer expires.
 174  */
 175 static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
 176 {
 177         struct alarm *alarm = container_of(timer, struct alarm, timer);
 178         struct alarm_base *base = &alarm_bases[alarm->type];
 179         unsigned long flags;
 180         int ret = HRTIMER_NORESTART;
 181         int restart = ALARMTIMER_NORESTART;
 182
 183         spin_lock_irqsave(&base->lock, flags);
 184         alarmtimer_dequeue(base, alarm);
 185         spin_unlock_irqrestore(&base->lock, flags);
 186
 187         if (alarm->function)
 188                 restart = alarm->function(alarm, base->gettime());
 189
 190         spin_lock_irqsave(&base->lock, flags);
 191         if (restart != ALARMTIMER_NORESTART) {
 192                 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
 193                 alarmtimer_enqueue(base, alarm);
 194                 ret = HRTIMER_RESTART;
 195         }
 196         spin_unlock_irqrestore(&base->lock, flags);
 197
 198         return ret;
 199
 200 }
 201
 202 #ifdef CONFIG_RTC_CLASS
 203 /**
 204  * alarmtimer_suspend - Suspend time callback
 205  * @dev: unused
 206  * @state: unused
 207  *
 208  * When we are going into suspend, we look through the bases
 209  * to see which is the soonest timer to expire. We then
 210  * set an rtc timer to fire that far into the future, which
 211  * will wake us from suspend.
 212  */
 213 static int alarmtimer_suspend(struct device *dev)
 214 {
 215         struct rtc_time tm;
 216         ktime_t min, now;
 217         unsigned long flags;
 218         struct rtc_device *rtc;
 219         int i;
 220         int ret;
 221
 222         spin_lock_irqsave(&freezer_delta_lock, flags);
 223         min = freezer_delta;
 224         freezer_delta = ktime_set(0, 0);
 225         spin_unlock_irqrestore(&freezer_delta_lock, flags);
 226
 227         rtc = alarmtimer_get_rtcdev();
 228         /* If we have no rtcdev, just return */
 229         if (!rtc)
 230                 return 0;
 231
 232         /* Find the soonest timer to expire*/
 233         for (i = 0; i < ALARM_NUMTYPE; i++) {
 234                 struct alarm_base *base = &alarm_bases[i];
 235                 struct timerqueue_node *next;
 236                 ktime_t delta;
 237
 238                 spin_lock_irqsave(&base->lock, flags);
 239                 next = timerqueue_getnext(&base->timerqueue);
 240                 spin_unlock_irqrestore(&base->lock, flags);
 241                 if (!next)
 242                         continue;
 243                 delta = ktime_sub(next->expires, base->gettime());
 244                 if (!min.tv64 || (delta.tv64 < min.tv64))
 245                         min = delta;
 246         }
 247         if (min.tv64 == 0)
 248                 return 0;
 249
 250         if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
 251                 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
 252                 return -EBUSY;
 253         }
 254
 255         /* Setup an rtc timer to fire that far in the future */
 256         rtc_timer_cancel(rtc, &rtctimer);
 257         rtc_read_time(rtc, &tm);
 258         now = rtc_tm_to_ktime(tm);
 259         now = ktime_add(now, min);
 260
 261         /* Set alarm, if in the past reject suspend briefly to handle */
 262         ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
 263         if (ret < 0)
 264                 __pm_wakeup_event(ws, MSEC_PER_SEC);
 265         return ret;
 266 }
 267 #else
 268 static int alarmtimer_suspend(struct device *dev)
 269 {
 270         return 0;
 271 }
 272 #endif
 273
 274 static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
 275 {
 276         ktime_t delta;
 277         unsigned long flags;
 278         struct alarm_base *base = &alarm_bases[type];
 279
 280         delta = ktime_sub(absexp, base->gettime());
 281
 282         spin_lock_irqsave(&freezer_delta_lock, flags);
 283         if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
 284                 freezer_delta = delta;
 285         spin_unlock_irqrestore(&freezer_delta_lock, flags);
 286 }
 287
 288
 289 /**
 290  * alarm_init - Initialize an alarm structure
 291  * @alarm: ptr to alarm to be initialized
 292  * @type: the type of the alarm
 293  * @function: callback that is run when the alarm fires
 294  */
 295 void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
 296                 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
 297 {
 298         timerqueue_init(&alarm->node);
 299         hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
 300                         HRTIMER_MODE_ABS);
 301         alarm->timer.function = alarmtimer_fired;
 302         alarm->function = function;
 303         alarm->type = type;
 304         alarm->state = ALARMTIMER_STATE_INACTIVE;
 305 }
 306
 307 /**
 308  * alarm_start - Sets an alarm to fire
 309  * @alarm: ptr to alarm to set
 310  * @start: time to run the alarm
 311  */
 312 int alarm_start(struct alarm *alarm, ktime_t start)
 313 {
 314         struct alarm_base *base = &alarm_bases[alarm->type];
 315         unsigned long flags;
 316         int ret;
 317
 318         spin_lock_irqsave(&base->lock, flags);
 319         alarm->node.expires = start;
 320         alarmtimer_enqueue(base, alarm);
 321         ret = hrtimer_start(&alarm->timer, alarm->node.expires,
 322                                 HRTIMER_MODE_ABS);
 323         spin_unlock_irqrestore(&base->lock, flags);
 324         return ret;
 325 }
 326
 327 /**
 328  * alarm_try_to_cancel - Tries to cancel an alarm timer
 329  * @alarm: ptr to alarm to be canceled
 330  *
 331  * Returns 1 if the timer was canceled, 0 if it was not running,
 332  * and -1 if the callback was running
 333  */
 334 int alarm_try_to_cancel(struct alarm *alarm)
 335 {
 336         struct alarm_base *base = &alarm_bases[alarm->type];
 337         unsigned long flags;
 338         int ret;
 339
 340         spin_lock_irqsave(&base->lock, flags);
 341         ret = hrtimer_try_to_cancel(&alarm->timer);
 342         if (ret >= 0)
 343                 alarmtimer_dequeue(base, alarm);
 344         spin_unlock_irqrestore(&base->lock, flags);
 345         return ret;
 346 }
 347
 348
 349 /**
 350  * alarm_cancel - Spins trying to cancel an alarm timer until it is done
 351  * @alarm: ptr to alarm to be canceled
 352  *
 353  * Returns 1 if the timer was canceled, 0 if it was not active.
 354  */
 355 int alarm_cancel(struct alarm *alarm)
 356 {
 357         for (;;) {
 358                 int ret = alarm_try_to_cancel(alarm);
 359                 if (ret >= 0)
 360                         return ret;
 361                 cpu_relax();
 362         }
 363 }
 364
 365
 366 u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
 367 {
 368         u64 overrun = 1;
 369         ktime_t delta;
 370
 371         delta = ktime_sub(now, alarm->node.expires);
 372
 373         if (delta.tv64 < 0)
 374                 return 0;
 375
 376         if (unlikely(delta.tv64 >= interval.tv64)) {
 377                 s64 incr = ktime_to_ns(interval);
 378
 379                 overrun = ktime_divns(delta, incr);
 380
 381                 alarm->node.expires = ktime_add_ns(alarm->node.expires,
 382                                                         incr*overrun);
 383
 384                 if (alarm->node.expires.tv64 > now.tv64)
 385                         return overrun;
 386                 /*
 387                  * This (and the ktime_add() below) is the
 388                  * correction for exact:
 389                  */
 390                 overrun++;
 391         }
 392
 393         alarm->node.expires = ktime_add(alarm->node.expires, interval);
 394         return overrun;
 395 }
 396
 397
 398
 399
 400 /**
 401  * clock2alarm - helper that converts from clockid to alarmtypes
 402  * @clockid: clockid.
 403  */
 404 static enum alarmtimer_type clock2alarm(clockid_t clockid)
 405 {
 406         if (clockid == CLOCK_REALTIME_ALARM)
 407                 return ALARM_REALTIME;
 408         if (clockid == CLOCK_BOOTTIME_ALARM)
 409                 return ALARM_BOOTTIME;
 410         return -1;
 411 }
 412
 413 /**
 414  * alarm_handle_timer - Callback for posix timers
 415  * @alarm: alarm that fired
 416  *
 417  * Posix timer callback for expired alarm timers.
 418  */
 419 static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
 420                                                         ktime_t now)
 421 {
 422         struct k_itimer *ptr = container_of(alarm, struct k_itimer,
 423                                                 it.alarm.alarmtimer);
 424         if (posix_timer_event(ptr, 0) != 0)
 425                 ptr->it_overrun++;
 426
 427         /* Re-add periodic timers */
 428         if (ptr->it.alarm.interval.tv64) {
 429                 ptr->it_overrun += alarm_forward(alarm, now,
 430                                                 ptr->it.alarm.interval);
 431                 return ALARMTIMER_RESTART;
 432         }
 433         return ALARMTIMER_NORESTART;
 434 }
 435
 436 /**
 437  * alarm_clock_getres - posix getres interface
 438  * @which_clock: clockid
 439  * @tp: timespec to fill
 440  *
 441  * Returns the granularity of underlying alarm base clock
 442  */
 443 static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
 444 {
 445         clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
 446
 447         if (!alarmtimer_get_rtcdev())
 448                 return -ENOTSUPP;
 449
 450         return hrtimer_get_res(baseid, tp);
 451 }
 452
 453 /**
 454  * alarm_clock_get - posix clock_get interface
 455  * @which_clock: clockid
 456  * @tp: timespec to fill.
 457  *
 458  * Provides the underlying alarm base time.
 459  */
 460 static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
 461 {
 462         struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
 463
 464         if (!alarmtimer_get_rtcdev())
 465                 return -ENOTSUPP;
 466
 467         *tp = ktime_to_timespec(base->gettime());
 468         return 0;
 469 }
 470
 471 /**
 472  * alarm_timer_create - posix timer_create interface
 473  * @new_timer: k_itimer pointer to manage
 474  *
 475  * Initializes the k_itimer structure.
 476  */
 477 static int alarm_timer_create(struct k_itimer *new_timer)
 478 {
 479         enum  alarmtimer_type type;
 480         struct alarm_base *base;
 481
 482         if (!alarmtimer_get_rtcdev())
 483                 return -ENOTSUPP;
 484
 485         if (!capable(CAP_WAKE_ALARM))
 486                 return -EPERM;
 487
 488         type = clock2alarm(new_timer->it_clock);
 489         base = &alarm_bases[type];
 490         alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
 491         return 0;
 492 }
 493
 494 /**
 495  * alarm_timer_get - posix timer_get interface
 496  * @new_timer: k_itimer pointer
 497  * @cur_setting: itimerspec data to fill
 498  *
 499  * Copies the itimerspec data out from the k_itimer
 500  */
 501 static void alarm_timer_get(struct k_itimer *timr,
 502                                 struct itimerspec *cur_setting)
 503 {
 504         memset(cur_setting, 0, sizeof(struct itimerspec));
 505
 506         cur_setting->it_interval =
 507                         ktime_to_timespec(timr->it.alarm.interval);
 508         cur_setting->it_value =
 509                 ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
 510         return;
 511 }
 512
 513 /**
 514  * alarm_timer_del - posix timer_del interface
 515  * @timr: k_itimer pointer to be deleted
 516  *
 517  * Cancels any programmed alarms for the given timer.
 518  */
 519 static int alarm_timer_del(struct k_itimer *timr)
 520 {
 521         if (!rtcdev)
 522                 return -ENOTSUPP;
 523
 524         if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
 525                 return TIMER_RETRY;
 526
 527         return 0;
 528 }
 529
 530 /**
 531  * alarm_timer_set - posix timer_set interface
 532  * @timr: k_itimer pointer to be deleted
 533  * @flags: timer flags
 534  * @new_setting: itimerspec to be used
 535  * @old_setting: itimerspec being replaced
 536  *
 537  * Sets the timer to new_setting, and starts the timer.
 538  */
 539 static int alarm_timer_set(struct k_itimer *timr, int flags,
 540                                 struct itimerspec *new_setting,
 541                                 struct itimerspec *old_setting)
 542 {
 543         if (!rtcdev)
 544                 return -ENOTSUPP;
 545
 546         if (old_setting)
 547                 alarm_timer_get(timr, old_setting);
 548
 549         /* If the timer was already set, cancel it */
 550         if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
 551                 return TIMER_RETRY;
 552
 553         /* start the timer */
 554         timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
 555         alarm_start(&timr->it.alarm.alarmtimer,
 556                         timespec_to_ktime(new_setting->it_value));
 557         return 0;
 558 }
 559
 560 /**
 561  * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
 562  * @alarm: ptr to alarm that fired
 563  *
 564  * Wakes up the task that set the alarmtimer
 565  */
 566 static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
 567                                                                 ktime_t now)
 568 {
 569         struct task_struct *task = (struct task_struct *)alarm->data;
 570
 571         alarm->data = NULL;
 572         if (task)
 573                 wake_up_process(task);
 574         return ALARMTIMER_NORESTART;
 575 }
 576
 577 /**
 578  * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
 579  * @alarm: ptr to alarmtimer
 580  * @absexp: absolute expiration time
 581  *
 582  * Sets the alarm timer and sleeps until it is fired or interrupted.
 583  */
 584 static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
 585 {
 586         alarm->data = (void *)current;
 587         do {
 588                 set_current_state(TASK_INTERRUPTIBLE);
 589                 alarm_start(alarm, absexp);
 590                 if (likely(alarm->data))
 591                         schedule();
 592
 593                 alarm_cancel(alarm);
 594         } while (alarm->data && !signal_pending(current));
 595
 596         __set_current_state(TASK_RUNNING);
 597
 598         return (alarm->data == NULL);
 599 }
 600
 601
 602 /**
 603  * update_rmtp - Update remaining timespec value
 604  * @exp: expiration time
 605  * @type: timer type
 606  * @rmtp: user pointer to remaining timepsec value
 607  *
 608  * Helper function that fills in rmtp value with time between
 609  * now and the exp value
 610  */
 611 static int update_rmtp(ktime_t exp, enum  alarmtimer_type type,
 612                         struct timespec __user *rmtp)
 613 {
 614         struct timespec rmt;
 615         ktime_t rem;
 616
 617         rem = ktime_sub(exp, alarm_bases[type].gettime());
 618
 619         if (rem.tv64 <= 0)
 620                 return 0;
 621         rmt = ktime_to_timespec(rem);
 622
 623         if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
 624                 return -EFAULT;
 625
 626         return 1;
 627
 628 }
 629
 630 /**
 631  * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
 632  * @restart: ptr to restart block
 633  *
 634  * Handles restarted clock_nanosleep calls
 635  */
 636 static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
 637 {
 638         enum  alarmtimer_type type = restart->nanosleep.clockid;
 639         ktime_t exp;
 640         struct timespec __user  *rmtp;
 641         struct alarm alarm;
 642         int ret = 0;
 643
 644         exp.tv64 = restart->nanosleep.expires;
 645         alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
 646
 647         if (alarmtimer_do_nsleep(&alarm, exp))
 648                 goto out;
 649
 650         if (freezing(current))
 651                 alarmtimer_freezerset(exp, type);
 652
 653         rmtp = restart->nanosleep.rmtp;
 654         if (rmtp) {
 655                 ret = update_rmtp(exp, type, rmtp);
 656                 if (ret <= 0)
 657                         goto out;
 658         }
 659
 660
 661         /* The other values in restart are already filled in */
 662         ret = -ERESTART_RESTARTBLOCK;
 663 out:
 664         return ret;
 665 }
 666
 667 /**
 668  * alarm_timer_nsleep - alarmtimer nanosleep
 669  * @which_clock: clockid
 670  * @flags: determins abstime or relative
 671  * @tsreq: requested sleep time (abs or rel)
 672  * @rmtp: remaining sleep time saved
 673  *
 674  * Handles clock_nanosleep calls against _ALARM clockids
 675  */
 676 static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
 677                      struct timespec *tsreq, struct timespec __user *rmtp)
 678 {
 679         enum  alarmtimer_type type = clock2alarm(which_clock);
 680         struct alarm alarm;
 681         ktime_t exp;
 682         int ret = 0;
 683         struct restart_block *restart;
 684
 685         if (!alarmtimer_get_rtcdev())
 686                 return -ENOTSUPP;
 687
 688         if (!capable(CAP_WAKE_ALARM))
 689                 return -EPERM;
 690
 691         alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
 692
 693         exp = timespec_to_ktime(*tsreq);
 694         /* Convert (if necessary) to absolute time */
 695         if (flags != TIMER_ABSTIME) {
 696                 ktime_t now = alarm_bases[type].gettime();
 697                 exp = ktime_add(now, exp);
 698         }
 699
 700         if (alarmtimer_do_nsleep(&alarm, exp))
 701                 goto out;
 702
 703         if (freezing(current))
 704                 alarmtimer_freezerset(exp, type);
 705
 706         /* abs timers don't set remaining time or restart */
 707         if (flags == TIMER_ABSTIME) {
 708                 ret = -ERESTARTNOHAND;
 709                 goto out;
 710         }
 711
 712         if (rmtp) {
 713                 ret = update_rmtp(exp, type, rmtp);
 714                 if (ret <= 0)
 715                         goto out;
 716         }
 717
 718         restart = &current_thread_info()->restart_block;
 719         restart->fn = alarm_timer_nsleep_restart;
 720         restart->nanosleep.clockid = type;
 721         restart->nanosleep.expires = exp.tv64;
 722         restart->nanosleep.rmtp = rmtp;
 723         ret = -ERESTART_RESTARTBLOCK;
 724
 725 out:
 726         return ret;
 727 }
 728
 729
 730 /* Suspend hook structures */
 731 static const struct dev_pm_ops alarmtimer_pm_ops = {
 732         .suspend = alarmtimer_suspend,
 733 };
 734
 735 static struct platform_driver alarmtimer_driver = {
 736         .driver = {
 737                 .name = "alarmtimer",
 738                 .pm = &alarmtimer_pm_ops,
 739         }
 740 };
 741
 742 /**
 743  * alarmtimer_init - Initialize alarm timer code
 744  *
 745  * This function initializes the alarm bases and registers
 746  * the posix clock ids.
 747  */
 748 static int __init alarmtimer_init(void)
 749 {
 750         struct platform_device *pdev;
 751         int error = 0;
 752         int i;
 753         struct k_clock alarm_clock = {
 754                 .clock_getres   = alarm_clock_getres,
 755                 .clock_get      = alarm_clock_get,
 756                 .timer_create   = alarm_timer_create,
 757                 .timer_set      = alarm_timer_set,
 758                 .timer_del      = alarm_timer_del,
 759                 .timer_get      = alarm_timer_get,
 760                 .nsleep         = alarm_timer_nsleep,
 761         };
 762
 763         alarmtimer_rtc_timer_init();
 764
 765         posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
 766         posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
 767
 768         /* Initialize alarm bases */
 769         alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
 770         alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
 771         alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
 772         alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
 773         for (i = 0; i < ALARM_NUMTYPE; i++) {
 774                 timerqueue_init_head(&alarm_bases[i].timerqueue);
 775                 spin_lock_init(&alarm_bases[i].lock);
 776         }
 777
 778         error = alarmtimer_rtc_interface_setup();
 779         if (error)
 780                 return error;
 781
 782         error = platform_driver_register(&alarmtimer_driver);
 783         if (error)
 784                 goto out_if;
 785
 786         pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
 787         if (IS_ERR(pdev)) {
 788                 error = PTR_ERR(pdev);
 789                 goto out_drv;
 790         }
 791         ws = wakeup_source_register("alarmtimer");
 792         return 0;
 793
 794 out_drv:
 795         platform_driver_unregister(&alarmtimer_driver);
 796 out_if:
 797         alarmtimer_rtc_interface_remove();
 798         return error;
 799 }
 800 device_initcall(alarmtimer_init);