4 * This interface provides a timer which is similarto hrtimers,
5 * but triggers a RTC alarm if the box is suspend.
7 * This interface is influenced by the Android RTC Alarm timer
10 * Copyright (C) 2010 IBM Corperation
12 * Author: John Stultz <john.stultz@linaro.org>
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.
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>
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
37 static struct alarm_base {
39 struct timerqueue_head timerqueue;
40 ktime_t (*gettime)(void);
41 clockid_t base_clockid;
42 } alarm_bases[ALARM_NUMTYPE];
44 /* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
45 static ktime_t freezer_delta;
46 static DEFINE_SPINLOCK(freezer_delta_lock);
48 static struct wakeup_source *ws;
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);
57 * alarmtimer_get_rtcdev - Return selected rtcdevice
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.
63 struct rtc_device *alarmtimer_get_rtcdev(void)
66 struct rtc_device *ret;
68 spin_lock_irqsave(&rtcdev_lock, flags);
70 spin_unlock_irqrestore(&rtcdev_lock, flags);
74 EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
76 static int alarmtimer_rtc_add_device(struct device *dev,
77 struct class_interface *class_intf)
80 struct rtc_device *rtc = to_rtc_device(dev);
85 if (!rtc->ops->set_alarm)
87 if (!device_may_wakeup(rtc->dev.parent))
90 spin_lock_irqsave(&rtcdev_lock, flags);
93 /* hold a reference so it doesn't go away */
96 spin_unlock_irqrestore(&rtcdev_lock, flags);
100 static inline void alarmtimer_rtc_timer_init(void)
102 rtc_timer_init(&rtctimer, NULL, NULL);
105 static struct class_interface alarmtimer_rtc_interface = {
106 .add_dev = &alarmtimer_rtc_add_device,
109 static int alarmtimer_rtc_interface_setup(void)
111 alarmtimer_rtc_interface.class = rtc_class;
112 return class_interface_register(&alarmtimer_rtc_interface);
114 static void alarmtimer_rtc_interface_remove(void)
116 class_interface_unregister(&alarmtimer_rtc_interface);
119 struct rtc_device *alarmtimer_get_rtcdev(void)
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) { }
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.
134 * Adds alarm to a alarm_base timerqueue
136 * Must hold base->lock when calling.
138 static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
140 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
141 timerqueue_del(&base->timerqueue, &alarm->node);
143 timerqueue_add(&base->timerqueue, &alarm->node);
144 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
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
152 * Removes alarm to a alarm_base timerqueue
154 * Must hold base->lock when calling.
156 static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
158 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
161 timerqueue_del(&base->timerqueue, &alarm->node);
162 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
167 * alarmtimer_fired - Handles alarm hrtimer being fired.
168 * @timer: pointer to hrtimer being run
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.
175 static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
177 struct alarm *alarm = container_of(timer, struct alarm, timer);
178 struct alarm_base *base = &alarm_bases[alarm->type];
180 int ret = HRTIMER_NORESTART;
181 int restart = ALARMTIMER_NORESTART;
183 spin_lock_irqsave(&base->lock, flags);
184 alarmtimer_dequeue(base, alarm);
185 spin_unlock_irqrestore(&base->lock, flags);
188 restart = alarm->function(alarm, base->gettime());
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;
196 spin_unlock_irqrestore(&base->lock, flags);
202 ktime_t alarm_expires_remaining(const struct alarm *alarm)
204 struct alarm_base *base = &alarm_bases[alarm->type];
205 return ktime_sub(alarm->node.expires, base->gettime());
207 EXPORT_SYMBOL_GPL(alarm_expires_remaining);
209 #ifdef CONFIG_RTC_CLASS
211 * alarmtimer_suspend - Suspend time callback
215 * When we are going into suspend, we look through the bases
216 * to see which is the soonest timer to expire. We then
217 * set an rtc timer to fire that far into the future, which
218 * will wake us from suspend.
220 static int alarmtimer_suspend(struct device *dev)
225 struct rtc_device *rtc;
229 spin_lock_irqsave(&freezer_delta_lock, flags);
231 freezer_delta = ktime_set(0, 0);
232 spin_unlock_irqrestore(&freezer_delta_lock, flags);
234 rtc = alarmtimer_get_rtcdev();
235 /* If we have no rtcdev, just return */
239 /* Find the soonest timer to expire*/
240 for (i = 0; i < ALARM_NUMTYPE; i++) {
241 struct alarm_base *base = &alarm_bases[i];
242 struct timerqueue_node *next;
245 spin_lock_irqsave(&base->lock, flags);
246 next = timerqueue_getnext(&base->timerqueue);
247 spin_unlock_irqrestore(&base->lock, flags);
250 delta = ktime_sub(next->expires, base->gettime());
251 if (!min.tv64 || (delta.tv64 < min.tv64))
257 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
258 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
262 /* Setup an rtc timer to fire that far in the future */
263 rtc_timer_cancel(rtc, &rtctimer);
264 rtc_read_time(rtc, &tm);
265 now = rtc_tm_to_ktime(tm);
266 now = ktime_add(now, min);
268 /* Set alarm, if in the past reject suspend briefly to handle */
269 ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
271 __pm_wakeup_event(ws, MSEC_PER_SEC);
275 static int alarmtimer_resume(struct device *dev)
277 struct rtc_device *rtc;
279 rtc = alarmtimer_get_rtcdev();
281 rtc_timer_cancel(rtc, &rtctimer);
286 static int alarmtimer_suspend(struct device *dev)
291 static int alarmtimer_resume(struct device *dev)
297 static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
301 struct alarm_base *base = &alarm_bases[type];
303 delta = ktime_sub(absexp, base->gettime());
305 spin_lock_irqsave(&freezer_delta_lock, flags);
306 if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
307 freezer_delta = delta;
308 spin_unlock_irqrestore(&freezer_delta_lock, flags);
313 * alarm_init - Initialize an alarm structure
314 * @alarm: ptr to alarm to be initialized
315 * @type: the type of the alarm
316 * @function: callback that is run when the alarm fires
318 void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
319 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
321 timerqueue_init(&alarm->node);
322 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
324 alarm->timer.function = alarmtimer_fired;
325 alarm->function = function;
327 alarm->state = ALARMTIMER_STATE_INACTIVE;
329 EXPORT_SYMBOL_GPL(alarm_init);
332 * alarm_start - Sets an absolute alarm to fire
333 * @alarm: ptr to alarm to set
334 * @start: time to run the alarm
336 void alarm_start(struct alarm *alarm, ktime_t start)
338 struct alarm_base *base = &alarm_bases[alarm->type];
341 spin_lock_irqsave(&base->lock, flags);
342 alarm->node.expires = start;
343 alarmtimer_enqueue(base, alarm);
344 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
345 spin_unlock_irqrestore(&base->lock, flags);
347 EXPORT_SYMBOL_GPL(alarm_start);
350 * alarm_start_relative - Sets a relative alarm to fire
351 * @alarm: ptr to alarm to set
352 * @start: time relative to now to run the alarm
354 void alarm_start_relative(struct alarm *alarm, ktime_t start)
356 struct alarm_base *base = &alarm_bases[alarm->type];
358 start = ktime_add(start, base->gettime());
359 alarm_start(alarm, start);
361 EXPORT_SYMBOL_GPL(alarm_start_relative);
363 void alarm_restart(struct alarm *alarm)
365 struct alarm_base *base = &alarm_bases[alarm->type];
368 spin_lock_irqsave(&base->lock, flags);
369 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
370 hrtimer_restart(&alarm->timer);
371 alarmtimer_enqueue(base, alarm);
372 spin_unlock_irqrestore(&base->lock, flags);
374 EXPORT_SYMBOL_GPL(alarm_restart);
377 * alarm_try_to_cancel - Tries to cancel an alarm timer
378 * @alarm: ptr to alarm to be canceled
380 * Returns 1 if the timer was canceled, 0 if it was not running,
381 * and -1 if the callback was running
383 int alarm_try_to_cancel(struct alarm *alarm)
385 struct alarm_base *base = &alarm_bases[alarm->type];
389 spin_lock_irqsave(&base->lock, flags);
390 ret = hrtimer_try_to_cancel(&alarm->timer);
392 alarmtimer_dequeue(base, alarm);
393 spin_unlock_irqrestore(&base->lock, flags);
396 EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
400 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
401 * @alarm: ptr to alarm to be canceled
403 * Returns 1 if the timer was canceled, 0 if it was not active.
405 int alarm_cancel(struct alarm *alarm)
408 int ret = alarm_try_to_cancel(alarm);
414 EXPORT_SYMBOL_GPL(alarm_cancel);
417 u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
422 delta = ktime_sub(now, alarm->node.expires);
427 if (unlikely(delta.tv64 >= interval.tv64)) {
428 s64 incr = ktime_to_ns(interval);
430 overrun = ktime_divns(delta, incr);
432 alarm->node.expires = ktime_add_ns(alarm->node.expires,
435 if (alarm->node.expires.tv64 > now.tv64)
438 * This (and the ktime_add() below) is the
439 * correction for exact:
444 alarm->node.expires = ktime_add(alarm->node.expires, interval);
447 EXPORT_SYMBOL_GPL(alarm_forward);
449 u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
451 struct alarm_base *base = &alarm_bases[alarm->type];
453 return alarm_forward(alarm, base->gettime(), interval);
455 EXPORT_SYMBOL_GPL(alarm_forward_now);
459 * clock2alarm - helper that converts from clockid to alarmtypes
462 static enum alarmtimer_type clock2alarm(clockid_t clockid)
464 if (clockid == CLOCK_REALTIME_ALARM)
465 return ALARM_REALTIME;
466 if (clockid == CLOCK_BOOTTIME_ALARM)
467 return ALARM_BOOTTIME;
472 * alarm_handle_timer - Callback for posix timers
473 * @alarm: alarm that fired
475 * Posix timer callback for expired alarm timers.
477 static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
481 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
482 it.alarm.alarmtimer);
483 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
485 spin_lock_irqsave(&ptr->it_lock, flags);
486 if ((ptr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) {
487 if (posix_timer_event(ptr, 0) != 0)
491 /* Re-add periodic timers */
492 if (ptr->it.alarm.interval.tv64) {
493 ptr->it_overrun += alarm_forward(alarm, now,
494 ptr->it.alarm.interval);
495 result = ALARMTIMER_RESTART;
497 spin_unlock_irqrestore(&ptr->it_lock, flags);
503 * alarm_clock_getres - posix getres interface
504 * @which_clock: clockid
505 * @tp: timespec to fill
507 * Returns the granularity of underlying alarm base clock
509 static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
511 if (!alarmtimer_get_rtcdev())
515 tp->tv_nsec = hrtimer_resolution;
520 * alarm_clock_get - posix clock_get interface
521 * @which_clock: clockid
522 * @tp: timespec to fill.
524 * Provides the underlying alarm base time.
526 static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
528 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
530 if (!alarmtimer_get_rtcdev())
533 *tp = ktime_to_timespec(base->gettime());
538 * alarm_timer_create - posix timer_create interface
539 * @new_timer: k_itimer pointer to manage
541 * Initializes the k_itimer structure.
543 static int alarm_timer_create(struct k_itimer *new_timer)
545 enum alarmtimer_type type;
546 struct alarm_base *base;
548 if (!alarmtimer_get_rtcdev())
551 if (!capable(CAP_WAKE_ALARM))
554 type = clock2alarm(new_timer->it_clock);
555 base = &alarm_bases[type];
556 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
561 * alarm_timer_get - posix timer_get interface
562 * @new_timer: k_itimer pointer
563 * @cur_setting: itimerspec data to fill
565 * Copies out the current itimerspec data
567 static void alarm_timer_get(struct k_itimer *timr,
568 struct itimerspec *cur_setting)
570 ktime_t relative_expiry_time =
571 alarm_expires_remaining(&(timr->it.alarm.alarmtimer));
573 if (ktime_to_ns(relative_expiry_time) > 0) {
574 cur_setting->it_value = ktime_to_timespec(relative_expiry_time);
576 cur_setting->it_value.tv_sec = 0;
577 cur_setting->it_value.tv_nsec = 0;
580 cur_setting->it_interval = ktime_to_timespec(timr->it.alarm.interval);
584 * alarm_timer_del - posix timer_del interface
585 * @timr: k_itimer pointer to be deleted
587 * Cancels any programmed alarms for the given timer.
589 static int alarm_timer_del(struct k_itimer *timr)
594 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
601 * alarm_timer_set - posix timer_set interface
602 * @timr: k_itimer pointer to be deleted
603 * @flags: timer flags
604 * @new_setting: itimerspec to be used
605 * @old_setting: itimerspec being replaced
607 * Sets the timer to new_setting, and starts the timer.
609 static int alarm_timer_set(struct k_itimer *timr, int flags,
610 struct itimerspec *new_setting,
611 struct itimerspec *old_setting)
618 if (flags & ~TIMER_ABSTIME)
622 alarm_timer_get(timr, old_setting);
624 /* If the timer was already set, cancel it */
625 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
628 /* start the timer */
629 timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
630 exp = timespec_to_ktime(new_setting->it_value);
631 /* Convert (if necessary) to absolute time */
632 if (flags != TIMER_ABSTIME) {
635 now = alarm_bases[timr->it.alarm.alarmtimer.type].gettime();
636 exp = ktime_add(now, exp);
639 alarm_start(&timr->it.alarm.alarmtimer, exp);
644 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
645 * @alarm: ptr to alarm that fired
647 * Wakes up the task that set the alarmtimer
649 static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
652 struct task_struct *task = (struct task_struct *)alarm->data;
656 wake_up_process(task);
657 return ALARMTIMER_NORESTART;
661 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
662 * @alarm: ptr to alarmtimer
663 * @absexp: absolute expiration time
665 * Sets the alarm timer and sleeps until it is fired or interrupted.
667 static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
669 alarm->data = (void *)current;
671 set_current_state(TASK_INTERRUPTIBLE);
672 alarm_start(alarm, absexp);
673 if (likely(alarm->data))
677 } while (alarm->data && !signal_pending(current));
679 __set_current_state(TASK_RUNNING);
681 return (alarm->data == NULL);
686 * update_rmtp - Update remaining timespec value
687 * @exp: expiration time
689 * @rmtp: user pointer to remaining timepsec value
691 * Helper function that fills in rmtp value with time between
692 * now and the exp value
694 static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
695 struct timespec __user *rmtp)
700 rem = ktime_sub(exp, alarm_bases[type].gettime());
704 rmt = ktime_to_timespec(rem);
706 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
714 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
715 * @restart: ptr to restart block
717 * Handles restarted clock_nanosleep calls
719 static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
721 enum alarmtimer_type type = restart->nanosleep.clockid;
723 struct timespec __user *rmtp;
727 exp.tv64 = restart->nanosleep.expires;
728 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
730 if (alarmtimer_do_nsleep(&alarm, exp))
733 if (freezing(current))
734 alarmtimer_freezerset(exp, type);
736 rmtp = restart->nanosleep.rmtp;
738 ret = update_rmtp(exp, type, rmtp);
744 /* The other values in restart are already filled in */
745 ret = -ERESTART_RESTARTBLOCK;
751 * alarm_timer_nsleep - alarmtimer nanosleep
752 * @which_clock: clockid
753 * @flags: determins abstime or relative
754 * @tsreq: requested sleep time (abs or rel)
755 * @rmtp: remaining sleep time saved
757 * Handles clock_nanosleep calls against _ALARM clockids
759 static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
760 struct timespec *tsreq, struct timespec __user *rmtp)
762 enum alarmtimer_type type = clock2alarm(which_clock);
766 struct restart_block *restart;
768 if (!alarmtimer_get_rtcdev())
771 if (flags & ~TIMER_ABSTIME)
774 if (!capable(CAP_WAKE_ALARM))
777 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
779 exp = timespec_to_ktime(*tsreq);
780 /* Convert (if necessary) to absolute time */
781 if (flags != TIMER_ABSTIME) {
782 ktime_t now = alarm_bases[type].gettime();
783 exp = ktime_add(now, exp);
786 if (alarmtimer_do_nsleep(&alarm, exp))
789 if (freezing(current))
790 alarmtimer_freezerset(exp, type);
792 /* abs timers don't set remaining time or restart */
793 if (flags == TIMER_ABSTIME) {
794 ret = -ERESTARTNOHAND;
799 ret = update_rmtp(exp, type, rmtp);
804 restart = ¤t->restart_block;
805 restart->fn = alarm_timer_nsleep_restart;
806 restart->nanosleep.clockid = type;
807 restart->nanosleep.expires = exp.tv64;
808 restart->nanosleep.rmtp = rmtp;
809 ret = -ERESTART_RESTARTBLOCK;
816 /* Suspend hook structures */
817 static const struct dev_pm_ops alarmtimer_pm_ops = {
818 .suspend = alarmtimer_suspend,
819 .resume = alarmtimer_resume,
822 static struct platform_driver alarmtimer_driver = {
824 .name = "alarmtimer",
825 .pm = &alarmtimer_pm_ops,
830 * alarmtimer_init - Initialize alarm timer code
832 * This function initializes the alarm bases and registers
833 * the posix clock ids.
835 static int __init alarmtimer_init(void)
837 struct platform_device *pdev;
840 struct k_clock alarm_clock = {
841 .clock_getres = alarm_clock_getres,
842 .clock_get = alarm_clock_get,
843 .timer_create = alarm_timer_create,
844 .timer_set = alarm_timer_set,
845 .timer_del = alarm_timer_del,
846 .timer_get = alarm_timer_get,
847 .nsleep = alarm_timer_nsleep,
850 alarmtimer_rtc_timer_init();
852 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
853 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
855 /* Initialize alarm bases */
856 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
857 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
858 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
859 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
860 for (i = 0; i < ALARM_NUMTYPE; i++) {
861 timerqueue_init_head(&alarm_bases[i].timerqueue);
862 spin_lock_init(&alarm_bases[i].lock);
865 error = alarmtimer_rtc_interface_setup();
869 error = platform_driver_register(&alarmtimer_driver);
873 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
875 error = PTR_ERR(pdev);
878 ws = wakeup_source_register("alarmtimer");
882 platform_driver_unregister(&alarmtimer_driver);
884 alarmtimer_rtc_interface_remove();
887 device_initcall(alarmtimer_init);