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
;
41 ktime_t (*gettime
)(void);
42 clockid_t base_clockid
;
43 } alarm_bases
[ALARM_NUMTYPE
];
45 /* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
46 static ktime_t freezer_delta
;
47 static DEFINE_SPINLOCK(freezer_delta_lock
);
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
);
56 * has_wakealarm - check rtc device has wakealarm ability
57 * @dev: current device
58 * @name_ptr: name to be returned
60 * This helper function checks to see if the rtc device can wake
63 static int has_wakealarm(struct device
*dev
, void *name_ptr
)
65 struct rtc_device
*candidate
= to_rtc_device(dev
);
67 if (!candidate
->ops
->set_alarm
)
69 if (!device_may_wakeup(candidate
->dev
.parent
))
72 *(const char **)name_ptr
= dev_name(dev
);
77 * alarmtimer_get_rtcdev - Return selected rtcdevice
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.
83 static struct rtc_device
*alarmtimer_get_rtcdev(void)
88 struct rtc_device
*ret
;
90 spin_lock_irqsave(&rtcdev_lock
, flags
);
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() */
96 rtcdev
= rtc_class_open(str
);
98 * Drop the reference we got in class_find_device,
99 * rtc_open takes its own.
102 rtc_timer_init(&rtctimer
, NULL
, NULL
);
106 spin_unlock_irqrestore(&rtcdev_lock
, flags
);
111 #define alarmtimer_get_rtcdev() (0)
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.
121 * Adds alarm to a alarm_base timerqueue and if necessary sets
124 * Must hold base->lock when calling.
126 static void alarmtimer_enqueue(struct alarm_base
*base
, struct alarm
*alarm
)
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
,
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
141 * Removes alarm to a alarm_base timerqueue and if necessary sets
142 * a new timer to run.
144 * Must hold base->lock when calling.
146 static void alarmtimer_remove(struct alarm_base
*base
, struct alarm
*alarm
)
148 struct timerqueue_node
*next
= timerqueue_getnext(&base
->timerqueue
);
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
);
156 hrtimer_start(&base
->timer
, next
->expires
, HRTIMER_MODE_ABS
);
162 * alarmtimer_fired - Handles alarm hrtimer being fired.
163 * @timer: pointer to hrtimer being run
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.
170 static enum hrtimer_restart
alarmtimer_fired(struct hrtimer
*timer
)
172 struct alarm_base
*base
= container_of(timer
, struct alarm_base
, timer
);
173 struct timerqueue_node
*next
;
176 int ret
= HRTIMER_NORESTART
;
177 int restart
= ALARMTIMER_NORESTART
;
179 spin_lock_irqsave(&base
->lock
, flags
);
180 now
= base
->gettime();
181 while ((next
= timerqueue_getnext(&base
->timerqueue
))) {
183 ktime_t expired
= next
->expires
;
185 if (expired
.tv64
>= now
.tv64
)
188 alarm
= container_of(next
, struct alarm
, node
);
190 timerqueue_del(&base
->timerqueue
, &alarm
->node
);
193 spin_unlock_irqrestore(&base
->lock
, flags
);
195 restart
= alarm
->function(alarm
, now
);
196 spin_lock_irqsave(&base
->lock
, flags
);
198 if (restart
!= ALARMTIMER_NORESTART
) {
199 timerqueue_add(&base
->timerqueue
, &alarm
->node
);
205 hrtimer_set_expires(&base
->timer
, next
->expires
);
206 ret
= HRTIMER_RESTART
;
208 spin_unlock_irqrestore(&base
->lock
, flags
);
214 #ifdef CONFIG_RTC_CLASS
216 * alarmtimer_suspend - Suspend time callback
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.
225 static int alarmtimer_suspend(struct device
*dev
)
230 struct rtc_device
*rtc
;
233 spin_lock_irqsave(&freezer_delta_lock
, flags
);
235 freezer_delta
= ktime_set(0, 0);
236 spin_unlock_irqrestore(&freezer_delta_lock
, flags
);
239 /* If we have no rtcdev, just return */
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
;
249 spin_lock_irqsave(&base
->lock
, flags
);
250 next
= timerqueue_getnext(&base
->timerqueue
);
251 spin_unlock_irqrestore(&base
->lock
, flags
);
254 delta
= ktime_sub(next
->expires
, base
->gettime());
255 if (!min
.tv64
|| (delta
.tv64
< min
.tv64
))
261 /* XXX - Should we enforce a minimum sleep time? */
262 WARN_ON(min
.tv64
< NSEC_PER_SEC
);
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
);
270 rtc_timer_start(rtc
, &rtctimer
, now
, ktime_set(0, 0));
275 static int alarmtimer_suspend(struct device
*dev
)
281 static void alarmtimer_freezerset(ktime_t absexp
, enum alarmtimer_type type
)
285 struct alarm_base
*base
= &alarm_bases
[type
];
287 delta
= ktime_sub(absexp
, base
->gettime());
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
);
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
302 void alarm_init(struct alarm
*alarm
, enum alarmtimer_type type
,
303 enum alarmtimer_restart (*function
)(struct alarm
*, ktime_t
))
305 timerqueue_init(&alarm
->node
);
306 alarm
->period
= ktime_set(0, 0);
307 alarm
->function
= function
;
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
318 void alarm_start(struct alarm
*alarm
, ktime_t start
, ktime_t period
)
320 struct alarm_base
*base
= &alarm_bases
[alarm
->type
];
323 spin_lock_irqsave(&base
->lock
, flags
);
325 alarmtimer_remove(base
, alarm
);
326 alarm
->node
.expires
= start
;
327 alarm
->period
= period
;
328 alarmtimer_enqueue(base
, alarm
);
330 spin_unlock_irqrestore(&base
->lock
, flags
);
334 * alarm_cancel - Tries to cancel an alarm timer
335 * @alarm: ptr to alarm to be canceled
337 void alarm_cancel(struct alarm
*alarm
)
339 struct alarm_base
*base
= &alarm_bases
[alarm
->type
];
342 spin_lock_irqsave(&base
->lock
, flags
);
344 alarmtimer_remove(base
, alarm
);
346 spin_unlock_irqrestore(&base
->lock
, flags
);
351 u64
alarm_forward(struct alarm
*alarm
, ktime_t now
, ktime_t interval
)
356 delta
= ktime_sub(now
, alarm
->node
.expires
);
361 if (unlikely(delta
.tv64
>= interval
.tv64
)) {
362 s64 incr
= ktime_to_ns(interval
);
364 overrun
= ktime_divns(delta
, incr
);
366 alarm
->node
.expires
= ktime_add_ns(alarm
->node
.expires
,
369 if (alarm
->node
.expires
.tv64
> now
.tv64
)
372 * This (and the ktime_add() below) is the
373 * correction for exact:
378 alarm
->node
.expires
= ktime_add(alarm
->node
.expires
, interval
);
386 * clock2alarm - helper that converts from clockid to alarmtypes
389 static enum alarmtimer_type
clock2alarm(clockid_t clockid
)
391 if (clockid
== CLOCK_REALTIME_ALARM
)
392 return ALARM_REALTIME
;
393 if (clockid
== CLOCK_BOOTTIME_ALARM
)
394 return ALARM_BOOTTIME
;
399 * alarm_handle_timer - Callback for posix timers
400 * @alarm: alarm that fired
402 * Posix timer callback for expired alarm timers.
404 static enum alarmtimer_restart
alarm_handle_timer(struct alarm
*alarm
,
407 struct k_itimer
*ptr
= container_of(alarm
, struct k_itimer
,
409 if (posix_timer_event(ptr
, 0) != 0)
412 /* Re-add periodic timers */
413 if (alarm
->period
.tv64
) {
414 ptr
->it_overrun
+= alarm_forward(alarm
, now
, alarm
->period
);
415 return ALARMTIMER_RESTART
;
417 return ALARMTIMER_NORESTART
;
421 * alarm_clock_getres - posix getres interface
422 * @which_clock: clockid
423 * @tp: timespec to fill
425 * Returns the granularity of underlying alarm base clock
427 static int alarm_clock_getres(const clockid_t which_clock
, struct timespec
*tp
)
429 clockid_t baseid
= alarm_bases
[clock2alarm(which_clock
)].base_clockid
;
431 if (!alarmtimer_get_rtcdev())
434 return hrtimer_get_res(baseid
, tp
);
438 * alarm_clock_get - posix clock_get interface
439 * @which_clock: clockid
440 * @tp: timespec to fill.
442 * Provides the underlying alarm base time.
444 static int alarm_clock_get(clockid_t which_clock
, struct timespec
*tp
)
446 struct alarm_base
*base
= &alarm_bases
[clock2alarm(which_clock
)];
448 if (!alarmtimer_get_rtcdev())
451 *tp
= ktime_to_timespec(base
->gettime());
456 * alarm_timer_create - posix timer_create interface
457 * @new_timer: k_itimer pointer to manage
459 * Initializes the k_itimer structure.
461 static int alarm_timer_create(struct k_itimer
*new_timer
)
463 enum alarmtimer_type type
;
464 struct alarm_base
*base
;
466 if (!alarmtimer_get_rtcdev())
469 if (!capable(CAP_WAKE_ALARM
))
472 type
= clock2alarm(new_timer
->it_clock
);
473 base
= &alarm_bases
[type
];
474 alarm_init(&new_timer
->it
.alarmtimer
, type
, alarm_handle_timer
);
479 * alarm_timer_get - posix timer_get interface
480 * @new_timer: k_itimer pointer
481 * @cur_setting: itimerspec data to fill
483 * Copies the itimerspec data out from the k_itimer
485 static void alarm_timer_get(struct k_itimer
*timr
,
486 struct itimerspec
*cur_setting
)
488 memset(cur_setting
, 0, sizeof(struct itimerspec
));
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
);
498 * alarm_timer_del - posix timer_del interface
499 * @timr: k_itimer pointer to be deleted
501 * Cancels any programmed alarms for the given timer.
503 static int alarm_timer_del(struct k_itimer
*timr
)
508 alarm_cancel(&timr
->it
.alarmtimer
);
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
519 * Sets the timer to new_setting, and starts the timer.
521 static int alarm_timer_set(struct k_itimer
*timr
, int flags
,
522 struct itimerspec
*new_setting
,
523 struct itimerspec
*old_setting
)
529 alarm_timer_get(timr
, old_setting
);
531 /* If the timer was already set, cancel it */
532 alarm_cancel(&timr
->it
.alarmtimer
);
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
));
542 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
543 * @alarm: ptr to alarm that fired
545 * Wakes up the task that set the alarmtimer
547 static enum alarmtimer_restart
alarmtimer_nsleep_wakeup(struct alarm
*alarm
,
550 struct task_struct
*task
= (struct task_struct
*)alarm
->data
;
554 wake_up_process(task
);
555 return ALARMTIMER_NORESTART
;
559 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
560 * @alarm: ptr to alarmtimer
561 * @absexp: absolute expiration time
563 * Sets the alarm timer and sleeps until it is fired or interrupted.
565 static int alarmtimer_do_nsleep(struct alarm
*alarm
, ktime_t absexp
)
567 alarm
->data
= (void *)current
;
569 set_current_state(TASK_INTERRUPTIBLE
);
570 alarm_start(alarm
, absexp
, ktime_set(0, 0));
571 if (likely(alarm
->data
))
575 } while (alarm
->data
&& !signal_pending(current
));
577 __set_current_state(TASK_RUNNING
);
579 return (alarm
->data
== NULL
);
584 * update_rmtp - Update remaining timespec value
585 * @exp: expiration time
587 * @rmtp: user pointer to remaining timepsec value
589 * Helper function that fills in rmtp value with time between
590 * now and the exp value
592 static int update_rmtp(ktime_t exp
, enum alarmtimer_type type
,
593 struct timespec __user
*rmtp
)
598 rem
= ktime_sub(exp
, alarm_bases
[type
].gettime());
602 rmt
= ktime_to_timespec(rem
);
604 if (copy_to_user(rmtp
, &rmt
, sizeof(*rmtp
)))
612 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
613 * @restart: ptr to restart block
615 * Handles restarted clock_nanosleep calls
617 static long __sched
alarm_timer_nsleep_restart(struct restart_block
*restart
)
619 enum alarmtimer_type type
= restart
->nanosleep
.clockid
;
621 struct timespec __user
*rmtp
;
625 exp
.tv64
= restart
->nanosleep
.expires
;
626 alarm_init(&alarm
, type
, alarmtimer_nsleep_wakeup
);
628 if (alarmtimer_do_nsleep(&alarm
, exp
))
631 if (freezing(current
))
632 alarmtimer_freezerset(exp
, type
);
634 rmtp
= restart
->nanosleep
.rmtp
;
636 ret
= update_rmtp(exp
, type
, rmtp
);
642 /* The other values in restart are already filled in */
643 ret
= -ERESTART_RESTARTBLOCK
;
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
655 * Handles clock_nanosleep calls against _ALARM clockids
657 static int alarm_timer_nsleep(const clockid_t which_clock
, int flags
,
658 struct timespec
*tsreq
, struct timespec __user
*rmtp
)
660 enum alarmtimer_type type
= clock2alarm(which_clock
);
664 struct restart_block
*restart
;
666 if (!alarmtimer_get_rtcdev())
669 if (!capable(CAP_WAKE_ALARM
))
672 alarm_init(&alarm
, type
, alarmtimer_nsleep_wakeup
);
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
);
681 if (alarmtimer_do_nsleep(&alarm
, exp
))
684 if (freezing(current
))
685 alarmtimer_freezerset(exp
, type
);
687 /* abs timers don't set remaining time or restart */
688 if (flags
== TIMER_ABSTIME
) {
689 ret
= -ERESTARTNOHAND
;
694 ret
= update_rmtp(exp
, type
, rmtp
);
699 restart
= ¤t_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
;
711 /* Suspend hook structures */
712 static const struct dev_pm_ops alarmtimer_pm_ops
= {
713 .suspend
= alarmtimer_suspend
,
716 static struct platform_driver alarmtimer_driver
= {
718 .name
= "alarmtimer",
719 .pm
= &alarmtimer_pm_ops
,
724 * alarmtimer_init - Initialize alarm timer code
726 * This function initializes the alarm bases and registers
727 * the posix clock ids.
729 static int __init
alarmtimer_init(void)
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
,
743 posix_timers_register_clock(CLOCK_REALTIME_ALARM
, &alarm_clock
);
744 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM
, &alarm_clock
);
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
,
757 alarm_bases
[i
].timer
.function
= alarmtimer_fired
;
759 error
= platform_driver_register(&alarmtimer_driver
);
760 platform_device_register_simple("alarmtimer", -1, NULL
, 0);
764 device_initcall(alarmtimer_init
);