projects/linux·blob v3.19 · refs

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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 <[email protected]>
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 */
37static 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 */
45static ktime_t freezer_delta;
46static DEFINE_SPINLOCK(freezer_delta_lock);
47
48static struct wakeup_source *ws;
49
50#ifdef CONFIG_RTC_CLASS
51/* rtc timer and device for setting alarm wakeups at suspend */
52static struct rtc_timer rtctimer;
53static struct rtc_device *rtcdev;
54static 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 */
63struct 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}
74EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
75
76static 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
100static inline void alarmtimer_rtc_timer_init(void)
101{
102 rtc_timer_init(&rtctimer, NULL, NULL);
103}
104
105static struct class_interface alarmtimer_rtc_interface = {
106 .add_dev = &alarmtimer_rtc_add_device,
107};
108
109static int alarmtimer_rtc_interface_setup(void)
110{
111 alarmtimer_rtc_interface.class = rtc_class;
112 return class_interface_register(&alarmtimer_rtc_interface);
113}
114static void alarmtimer_rtc_interface_remove(void)
115{
116 class_interface_unregister(&alarmtimer_rtc_interface);
117}
118#else
119struct rtc_device *alarmtimer_get_rtcdev(void)
120{
121 return NULL;
122}
123#define rtcdev (NULL)
124static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
125static inline void alarmtimer_rtc_interface_remove(void) { }
126static 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 */
138static 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 */
156static 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 */
175static 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
202ktime_t alarm_expires_remaining(const struct alarm *alarm)
203{
204 struct alarm_base *base = &alarm_bases[alarm->type];
205 return ktime_sub(alarm->node.expires, base->gettime());
206}
207EXPORT_SYMBOL_GPL(alarm_expires_remaining);
208
209#ifdef CONFIG_RTC_CLASS
210/**
211 * alarmtimer_suspend - Suspend time callback
212 * @dev: unused
213 * @state: unused
214 *
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.
219 */
220static int alarmtimer_suspend(struct device *dev)
221{
222 struct rtc_time tm;
223 ktime_t min, now;
224 unsigned long flags;
225 struct rtc_device *rtc;
226 int i;
227 int ret;
228
229 spin_lock_irqsave(&freezer_delta_lock, flags);
230 min = freezer_delta;
231 freezer_delta = ktime_set(0, 0);
232 spin_unlock_irqrestore(&freezer_delta_lock, flags);
233
234 rtc = alarmtimer_get_rtcdev();
235 /* If we have no rtcdev, just return */
236 if (!rtc)
237 return 0;
238
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;
243 ktime_t delta;
244
245 spin_lock_irqsave(&base->lock, flags);
246 next = timerqueue_getnext(&base->timerqueue);
247 spin_unlock_irqrestore(&base->lock, flags);
248 if (!next)
249 continue;
250 delta = ktime_sub(next->expires, base->gettime());
251 if (!min.tv64 || (delta.tv64 < min.tv64))
252 min = delta;
253 }
254 if (min.tv64 == 0)
255 return 0;
256
257 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
258 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
259 return -EBUSY;
260 }
261
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);
267
268 /* Set alarm, if in the past reject suspend briefly to handle */
269 ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
270 if (ret < 0)
271 __pm_wakeup_event(ws, MSEC_PER_SEC);
272 return ret;
273}
274#else
275static int alarmtimer_suspend(struct device *dev)
276{
277 return 0;
278}
279#endif
280
281static 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 */
302void 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 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
307 HRTIMER_MODE_ABS);
308 alarm->timer.function = alarmtimer_fired;
309 alarm->function = function;
310 alarm->type = type;
311 alarm->state = ALARMTIMER_STATE_INACTIVE;
312}
313EXPORT_SYMBOL_GPL(alarm_init);
314
315/**
316 * alarm_start - Sets an absolute alarm to fire
317 * @alarm: ptr to alarm to set
318 * @start: time to run the alarm
319 */
320int alarm_start(struct alarm *alarm, ktime_t start)
321{
322 struct alarm_base *base = &alarm_bases[alarm->type];
323 unsigned long flags;
324 int ret;
325
326 spin_lock_irqsave(&base->lock, flags);
327 alarm->node.expires = start;
328 alarmtimer_enqueue(base, alarm);
329 ret = hrtimer_start(&alarm->timer, alarm->node.expires,
330 HRTIMER_MODE_ABS);
331 spin_unlock_irqrestore(&base->lock, flags);
332 return ret;
333}
334EXPORT_SYMBOL_GPL(alarm_start);
335
336/**
337 * alarm_start_relative - Sets a relative alarm to fire
338 * @alarm: ptr to alarm to set
339 * @start: time relative to now to run the alarm
340 */
341int alarm_start_relative(struct alarm *alarm, ktime_t start)
342{
343 struct alarm_base *base = &alarm_bases[alarm->type];
344
345 start = ktime_add(start, base->gettime());
346 return alarm_start(alarm, start);
347}
348EXPORT_SYMBOL_GPL(alarm_start_relative);
349
350void alarm_restart(struct alarm *alarm)
351{
352 struct alarm_base *base = &alarm_bases[alarm->type];
353 unsigned long flags;
354
355 spin_lock_irqsave(&base->lock, flags);
356 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
357 hrtimer_restart(&alarm->timer);
358 alarmtimer_enqueue(base, alarm);
359 spin_unlock_irqrestore(&base->lock, flags);
360}
361EXPORT_SYMBOL_GPL(alarm_restart);
362
363/**
364 * alarm_try_to_cancel - Tries to cancel an alarm timer
365 * @alarm: ptr to alarm to be canceled
366 *
367 * Returns 1 if the timer was canceled, 0 if it was not running,
368 * and -1 if the callback was running
369 */
370int alarm_try_to_cancel(struct alarm *alarm)
371{
372 struct alarm_base *base = &alarm_bases[alarm->type];
373 unsigned long flags;
374 int ret;
375
376 spin_lock_irqsave(&base->lock, flags);
377 ret = hrtimer_try_to_cancel(&alarm->timer);
378 if (ret >= 0)
379 alarmtimer_dequeue(base, alarm);
380 spin_unlock_irqrestore(&base->lock, flags);
381 return ret;
382}
383EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
384
385
386/**
387 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
388 * @alarm: ptr to alarm to be canceled
389 *
390 * Returns 1 if the timer was canceled, 0 if it was not active.
391 */
392int alarm_cancel(struct alarm *alarm)
393{
394 for (;;) {
395 int ret = alarm_try_to_cancel(alarm);
396 if (ret >= 0)
397 return ret;
398 cpu_relax();
399 }
400}
401EXPORT_SYMBOL_GPL(alarm_cancel);
402
403
404u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
405{
406 u64 overrun = 1;
407 ktime_t delta;
408
409 delta = ktime_sub(now, alarm->node.expires);
410
411 if (delta.tv64 < 0)
412 return 0;
413
414 if (unlikely(delta.tv64 >= interval.tv64)) {
415 s64 incr = ktime_to_ns(interval);
416
417 overrun = ktime_divns(delta, incr);
418
419 alarm->node.expires = ktime_add_ns(alarm->node.expires,
420 incr*overrun);
421
422 if (alarm->node.expires.tv64 > now.tv64)
423 return overrun;
424 /*
425 * This (and the ktime_add() below) is the
426 * correction for exact:
427 */
428 overrun++;
429 }
430
431 alarm->node.expires = ktime_add(alarm->node.expires, interval);
432 return overrun;
433}
434EXPORT_SYMBOL_GPL(alarm_forward);
435
436u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
437{
438 struct alarm_base *base = &alarm_bases[alarm->type];
439
440 return alarm_forward(alarm, base->gettime(), interval);
441}
442EXPORT_SYMBOL_GPL(alarm_forward_now);
443
444
445/**
446 * clock2alarm - helper that converts from clockid to alarmtypes
447 * @clockid: clockid.
448 */
449static enum alarmtimer_type clock2alarm(clockid_t clockid)
450{
451 if (clockid == CLOCK_REALTIME_ALARM)
452 return ALARM_REALTIME;
453 if (clockid == CLOCK_BOOTTIME_ALARM)
454 return ALARM_BOOTTIME;
455 return -1;
456}
457
458/**
459 * alarm_handle_timer - Callback for posix timers
460 * @alarm: alarm that fired
461 *
462 * Posix timer callback for expired alarm timers.
463 */
464static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
465 ktime_t now)
466{
467 unsigned long flags;
468 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
469 it.alarm.alarmtimer);
470 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
471
472 spin_lock_irqsave(&ptr->it_lock, flags);
473 if ((ptr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) {
474 if (posix_timer_event(ptr, 0) != 0)
475 ptr->it_overrun++;
476 }
477
478 /* Re-add periodic timers */
479 if (ptr->it.alarm.interval.tv64) {
480 ptr->it_overrun += alarm_forward(alarm, now,
481 ptr->it.alarm.interval);
482 result = ALARMTIMER_RESTART;
483 }
484 spin_unlock_irqrestore(&ptr->it_lock, flags);
485
486 return result;
487}
488
489/**
490 * alarm_clock_getres - posix getres interface
491 * @which_clock: clockid
492 * @tp: timespec to fill
493 *
494 * Returns the granularity of underlying alarm base clock
495 */
496static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
497{
498 clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
499
500 if (!alarmtimer_get_rtcdev())
501 return -EINVAL;
502
503 return hrtimer_get_res(baseid, tp);
504}
505
506/**
507 * alarm_clock_get - posix clock_get interface
508 * @which_clock: clockid
509 * @tp: timespec to fill.
510 *
511 * Provides the underlying alarm base time.
512 */
513static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
514{
515 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
516
517 if (!alarmtimer_get_rtcdev())
518 return -EINVAL;
519
520 *tp = ktime_to_timespec(base->gettime());
521 return 0;
522}
523
524/**
525 * alarm_timer_create - posix timer_create interface
526 * @new_timer: k_itimer pointer to manage
527 *
528 * Initializes the k_itimer structure.
529 */
530static int alarm_timer_create(struct k_itimer *new_timer)
531{
532 enum alarmtimer_type type;
533 struct alarm_base *base;
534
535 if (!alarmtimer_get_rtcdev())
536 return -ENOTSUPP;
537
538 if (!capable(CAP_WAKE_ALARM))
539 return -EPERM;
540
541 type = clock2alarm(new_timer->it_clock);
542 base = &alarm_bases[type];
543 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
544 return 0;
545}
546
547/**
548 * alarm_timer_get - posix timer_get interface
549 * @new_timer: k_itimer pointer
550 * @cur_setting: itimerspec data to fill
551 *
552 * Copies out the current itimerspec data
553 */
554static void alarm_timer_get(struct k_itimer *timr,
555 struct itimerspec *cur_setting)
556{
557 ktime_t relative_expiry_time =
558 alarm_expires_remaining(&(timr->it.alarm.alarmtimer));
559
560 if (ktime_to_ns(relative_expiry_time) > 0) {
561 cur_setting->it_value = ktime_to_timespec(relative_expiry_time);
562 } else {
563 cur_setting->it_value.tv_sec = 0;
564 cur_setting->it_value.tv_nsec = 0;
565 }
566
567 cur_setting->it_interval = ktime_to_timespec(timr->it.alarm.interval);
568}
569
570/**
571 * alarm_timer_del - posix timer_del interface
572 * @timr: k_itimer pointer to be deleted
573 *
574 * Cancels any programmed alarms for the given timer.
575 */
576static int alarm_timer_del(struct k_itimer *timr)
577{
578 if (!rtcdev)
579 return -ENOTSUPP;
580
581 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
582 return TIMER_RETRY;
583
584 return 0;
585}
586
587/**
588 * alarm_timer_set - posix timer_set interface
589 * @timr: k_itimer pointer to be deleted
590 * @flags: timer flags
591 * @new_setting: itimerspec to be used
592 * @old_setting: itimerspec being replaced
593 *
594 * Sets the timer to new_setting, and starts the timer.
595 */
596static int alarm_timer_set(struct k_itimer *timr, int flags,
597 struct itimerspec *new_setting,
598 struct itimerspec *old_setting)
599{
600 ktime_t exp;
601
602 if (!rtcdev)
603 return -ENOTSUPP;
604
605 if (flags & ~TIMER_ABSTIME)
606 return -EINVAL;
607
608 if (old_setting)
609 alarm_timer_get(timr, old_setting);
610
611 /* If the timer was already set, cancel it */
612 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
613 return TIMER_RETRY;
614
615 /* start the timer */
616 timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
617 exp = timespec_to_ktime(new_setting->it_value);
618 /* Convert (if necessary) to absolute time */
619 if (flags != TIMER_ABSTIME) {
620 ktime_t now;
621
622 now = alarm_bases[timr->it.alarm.alarmtimer.type].gettime();
623 exp = ktime_add(now, exp);
624 }
625
626 alarm_start(&timr->it.alarm.alarmtimer, exp);
627 return 0;
628}
629
630/**
631 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
632 * @alarm: ptr to alarm that fired
633 *
634 * Wakes up the task that set the alarmtimer
635 */
636static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
637 ktime_t now)
638{
639 struct task_struct *task = (struct task_struct *)alarm->data;
640
641 alarm->data = NULL;
642 if (task)
643 wake_up_process(task);
644 return ALARMTIMER_NORESTART;
645}
646
647/**
648 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
649 * @alarm: ptr to alarmtimer
650 * @absexp: absolute expiration time
651 *
652 * Sets the alarm timer and sleeps until it is fired or interrupted.
653 */
654static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
655{
656 alarm->data = (void *)current;
657 do {
658 set_current_state(TASK_INTERRUPTIBLE);
659 alarm_start(alarm, absexp);
660 if (likely(alarm->data))
661 schedule();
662
663 alarm_cancel(alarm);
664 } while (alarm->data && !signal_pending(current));
665
666 __set_current_state(TASK_RUNNING);
667
668 return (alarm->data == NULL);
669}
670
671
672/**
673 * update_rmtp - Update remaining timespec value
674 * @exp: expiration time
675 * @type: timer type
676 * @rmtp: user pointer to remaining timepsec value
677 *
678 * Helper function that fills in rmtp value with time between
679 * now and the exp value
680 */
681static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
682 struct timespec __user *rmtp)
683{
684 struct timespec rmt;
685 ktime_t rem;
686
687 rem = ktime_sub(exp, alarm_bases[type].gettime());
688
689 if (rem.tv64 <= 0)
690 return 0;
691 rmt = ktime_to_timespec(rem);
692
693 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
694 return -EFAULT;
695
696 return 1;
697
698}
699
700/**
701 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
702 * @restart: ptr to restart block
703 *
704 * Handles restarted clock_nanosleep calls
705 */
706static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
707{
708 enum alarmtimer_type type = restart->nanosleep.clockid;
709 ktime_t exp;
710 struct timespec __user *rmtp;
711 struct alarm alarm;
712 int ret = 0;
713
714 exp.tv64 = restart->nanosleep.expires;
715 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
716
717 if (alarmtimer_do_nsleep(&alarm, exp))
718 goto out;
719
720 if (freezing(current))
721 alarmtimer_freezerset(exp, type);
722
723 rmtp = restart->nanosleep.rmtp;
724 if (rmtp) {
725 ret = update_rmtp(exp, type, rmtp);
726 if (ret <= 0)
727 goto out;
728 }
729
730
731 /* The other values in restart are already filled in */
732 ret = -ERESTART_RESTARTBLOCK;
733out:
734 return ret;
735}
736
737/**
738 * alarm_timer_nsleep - alarmtimer nanosleep
739 * @which_clock: clockid
740 * @flags: determins abstime or relative
741 * @tsreq: requested sleep time (abs or rel)
742 * @rmtp: remaining sleep time saved
743 *
744 * Handles clock_nanosleep calls against _ALARM clockids
745 */
746static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
747 struct timespec *tsreq, struct timespec __user *rmtp)
748{
749 enum alarmtimer_type type = clock2alarm(which_clock);
750 struct alarm alarm;
751 ktime_t exp;
752 int ret = 0;
753 struct restart_block *restart;
754
755 if (!alarmtimer_get_rtcdev())
756 return -ENOTSUPP;
757
758 if (flags & ~TIMER_ABSTIME)
759 return -EINVAL;
760
761 if (!capable(CAP_WAKE_ALARM))
762 return -EPERM;
763
764 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
765
766 exp = timespec_to_ktime(*tsreq);
767 /* Convert (if necessary) to absolute time */
768 if (flags != TIMER_ABSTIME) {
769 ktime_t now = alarm_bases[type].gettime();
770 exp = ktime_add(now, exp);
771 }
772
773 if (alarmtimer_do_nsleep(&alarm, exp))
774 goto out;
775
776 if (freezing(current))
777 alarmtimer_freezerset(exp, type);
778
779 /* abs timers don't set remaining time or restart */
780 if (flags == TIMER_ABSTIME) {
781 ret = -ERESTARTNOHAND;
782 goto out;
783 }
784
785 if (rmtp) {
786 ret = update_rmtp(exp, type, rmtp);
787 if (ret <= 0)
788 goto out;
789 }
790
791 restart = &current_thread_info()->restart_block;
792 restart->fn = alarm_timer_nsleep_restart;
793 restart->nanosleep.clockid = type;
794 restart->nanosleep.expires = exp.tv64;
795 restart->nanosleep.rmtp = rmtp;
796 ret = -ERESTART_RESTARTBLOCK;
797
798out:
799 return ret;
800}
801
802
803/* Suspend hook structures */
804static const struct dev_pm_ops alarmtimer_pm_ops = {
805 .suspend = alarmtimer_suspend,
806};
807
808static struct platform_driver alarmtimer_driver = {
809 .driver = {
810 .name = "alarmtimer",
811 .pm = &alarmtimer_pm_ops,
812 }
813};
814
815/**
816 * alarmtimer_init - Initialize alarm timer code
817 *
818 * This function initializes the alarm bases and registers
819 * the posix clock ids.
820 */
821static int __init alarmtimer_init(void)
822{
823 struct platform_device *pdev;
824 int error = 0;
825 int i;
826 struct k_clock alarm_clock = {
827 .clock_getres = alarm_clock_getres,
828 .clock_get = alarm_clock_get,
829 .timer_create = alarm_timer_create,
830 .timer_set = alarm_timer_set,
831 .timer_del = alarm_timer_del,
832 .timer_get = alarm_timer_get,
833 .nsleep = alarm_timer_nsleep,
834 };
835
836 alarmtimer_rtc_timer_init();
837
838 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
839 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
840
841 /* Initialize alarm bases */
842 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
843 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
844 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
845 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
846 for (i = 0; i < ALARM_NUMTYPE; i++) {
847 timerqueue_init_head(&alarm_bases[i].timerqueue);
848 spin_lock_init(&alarm_bases[i].lock);
849 }
850
851 error = alarmtimer_rtc_interface_setup();
852 if (error)
853 return error;
854
855 error = platform_driver_register(&alarmtimer_driver);
856 if (error)
857 goto out_if;
858
859 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
860 if (IS_ERR(pdev)) {
861 error = PTR_ERR(pdev);
862 goto out_drv;
863 }
864 ws = wakeup_source_register("alarmtimer");
865 return 0;
866
867out_drv:
868 platform_driver_unregister(&alarmtimer_driver);
869out_if:
870 alarmtimer_rtc_interface_remove();
871 return error;
872}
873device_initcall(alarmtimer_init);