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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 <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 */
37static 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 */
46static ktime_t freezer_delta;
47static DEFINE_SPINLOCK(freezer_delta_lock);
48
49#ifdef CONFIG_RTC_CLASS
50/* rtc timer and device for setting alarm wakeups at suspend */
51static struct rtc_timer rtctimer;
52static struct rtc_device *rtcdev;
53static DEFINE_SPINLOCK(rtcdev_lock);
54
55/**
56 * alarmtimer_get_rtcdev - Return selected rtcdevice
57 *
58 * This function returns the rtc device to use for wakealarms.
59 * If one has not already been chosen, it checks to see if a
60 * functional rtc device is available.
61 */
62struct rtc_device *alarmtimer_get_rtcdev(void)
63{
64 unsigned long flags;
65 struct rtc_device *ret;
66
67 spin_lock_irqsave(&rtcdev_lock, flags);
68 ret = rtcdev;
69 spin_unlock_irqrestore(&rtcdev_lock, flags);
70
71 return ret;
72}
73
74
75static int alarmtimer_rtc_add_device(struct device *dev,
76 struct class_interface *class_intf)
77{
78 unsigned long flags;
79 struct rtc_device *rtc = to_rtc_device(dev);
80
81 if (rtcdev)
82 return -EBUSY;
83
84 if (!rtc->ops->set_alarm)
85 return -1;
86 if (!device_may_wakeup(rtc->dev.parent))
87 return -1;
88
89 spin_lock_irqsave(&rtcdev_lock, flags);
90 if (!rtcdev) {
91 rtcdev = rtc;
92 /* hold a reference so it doesn't go away */
93 get_device(dev);
94 }
95 spin_unlock_irqrestore(&rtcdev_lock, flags);
96 return 0;
97}
98
99static inline void alarmtimer_rtc_timer_init(void)
100{
101 rtc_timer_init(&rtctimer, NULL, NULL);
102}
103
104static struct class_interface alarmtimer_rtc_interface = {
105 .add_dev = &alarmtimer_rtc_add_device,
106};
107
108static int alarmtimer_rtc_interface_setup(void)
109{
110 alarmtimer_rtc_interface.class = rtc_class;
111 return class_interface_register(&alarmtimer_rtc_interface);
112}
113static void alarmtimer_rtc_interface_remove(void)
114{
115 class_interface_unregister(&alarmtimer_rtc_interface);
116}
117#else
118struct rtc_device *alarmtimer_get_rtcdev(void)
119{
120 return NULL;
121}
122#define rtcdev (NULL)
123static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
124static inline void alarmtimer_rtc_interface_remove(void) { }
125static inline void alarmtimer_rtc_timer_init(void) { }
126#endif
127
128/**
129 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
130 * @base: pointer to the base where the timer is being run
131 * @alarm: pointer to alarm being enqueued.
132 *
133 * Adds alarm to a alarm_base timerqueue and if necessary sets
134 * an hrtimer to run.
135 *
136 * Must hold base->lock when calling.
137 */
138static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
139{
140 timerqueue_add(&base->timerqueue, &alarm->node);
141 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
142
143 if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
144 hrtimer_try_to_cancel(&base->timer);
145 hrtimer_start(&base->timer, alarm->node.expires,
146 HRTIMER_MODE_ABS);
147 }
148}
149
150/**
151 * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
152 * @base: pointer to the base where the timer is running
153 * @alarm: pointer to alarm being removed
154 *
155 * Removes alarm to a alarm_base timerqueue and if necessary sets
156 * a new timer to run.
157 *
158 * Must hold base->lock when calling.
159 */
160static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
161{
162 struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);
163
164 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
165 return;
166
167 timerqueue_del(&base->timerqueue, &alarm->node);
168 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
169
170 if (next == &alarm->node) {
171 hrtimer_try_to_cancel(&base->timer);
172 next = timerqueue_getnext(&base->timerqueue);
173 if (!next)
174 return;
175 hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);
176 }
177}
178
179
180/**
181 * alarmtimer_fired - Handles alarm hrtimer being fired.
182 * @timer: pointer to hrtimer being run
183 *
184 * When a alarm timer fires, this runs through the timerqueue to
185 * see which alarms expired, and runs those. If there are more alarm
186 * timers queued for the future, we set the hrtimer to fire when
187 * when the next future alarm timer expires.
188 */
189static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
190{
191 struct alarm_base *base = container_of(timer, struct alarm_base, timer);
192 struct timerqueue_node *next;
193 unsigned long flags;
194 ktime_t now;
195 int ret = HRTIMER_NORESTART;
196 int restart = ALARMTIMER_NORESTART;
197
198 spin_lock_irqsave(&base->lock, flags);
199 now = base->gettime();
200 while ((next = timerqueue_getnext(&base->timerqueue))) {
201 struct alarm *alarm;
202 ktime_t expired = next->expires;
203
204 if (expired.tv64 > now.tv64)
205 break;
206
207 alarm = container_of(next, struct alarm, node);
208
209 timerqueue_del(&base->timerqueue, &alarm->node);
210 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
211
212 alarm->state |= ALARMTIMER_STATE_CALLBACK;
213 spin_unlock_irqrestore(&base->lock, flags);
214 if (alarm->function)
215 restart = alarm->function(alarm, now);
216 spin_lock_irqsave(&base->lock, flags);
217 alarm->state &= ~ALARMTIMER_STATE_CALLBACK;
218
219 if (restart != ALARMTIMER_NORESTART) {
220 timerqueue_add(&base->timerqueue, &alarm->node);
221 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
222 }
223 }
224
225 if (next) {
226 hrtimer_set_expires(&base->timer, next->expires);
227 ret = HRTIMER_RESTART;
228 }
229 spin_unlock_irqrestore(&base->lock, flags);
230
231 return ret;
232
233}
234
235#ifdef CONFIG_RTC_CLASS
236/**
237 * alarmtimer_suspend - Suspend time callback
238 * @dev: unused
239 * @state: unused
240 *
241 * When we are going into suspend, we look through the bases
242 * to see which is the soonest timer to expire. We then
243 * set an rtc timer to fire that far into the future, which
244 * will wake us from suspend.
245 */
246static int alarmtimer_suspend(struct device *dev)
247{
248 struct rtc_time tm;
249 ktime_t min, now;
250 unsigned long flags;
251 struct rtc_device *rtc;
252 int i;
253
254 spin_lock_irqsave(&freezer_delta_lock, flags);
255 min = freezer_delta;
256 freezer_delta = ktime_set(0, 0);
257 spin_unlock_irqrestore(&freezer_delta_lock, flags);
258
259 rtc = alarmtimer_get_rtcdev();
260 /* If we have no rtcdev, just return */
261 if (!rtc)
262 return 0;
263
264 /* Find the soonest timer to expire*/
265 for (i = 0; i < ALARM_NUMTYPE; i++) {
266 struct alarm_base *base = &alarm_bases[i];
267 struct timerqueue_node *next;
268 ktime_t delta;
269
270 spin_lock_irqsave(&base->lock, flags);
271 next = timerqueue_getnext(&base->timerqueue);
272 spin_unlock_irqrestore(&base->lock, flags);
273 if (!next)
274 continue;
275 delta = ktime_sub(next->expires, base->gettime());
276 if (!min.tv64 || (delta.tv64 < min.tv64))
277 min = delta;
278 }
279 if (min.tv64 == 0)
280 return 0;
281
282 /* XXX - Should we enforce a minimum sleep time? */
283 WARN_ON(min.tv64 < NSEC_PER_SEC);
284
285 /* Setup an rtc timer to fire that far in the future */
286 rtc_timer_cancel(rtc, &rtctimer);
287 rtc_read_time(rtc, &tm);
288 now = rtc_tm_to_ktime(tm);
289 now = ktime_add(now, min);
290
291 rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
292
293 return 0;
294}
295#else
296static int alarmtimer_suspend(struct device *dev)
297{
298 return 0;
299}
300#endif
301
302static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
303{
304 ktime_t delta;
305 unsigned long flags;
306 struct alarm_base *base = &alarm_bases[type];
307
308 delta = ktime_sub(absexp, base->gettime());
309
310 spin_lock_irqsave(&freezer_delta_lock, flags);
311 if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
312 freezer_delta = delta;
313 spin_unlock_irqrestore(&freezer_delta_lock, flags);
314}
315
316
317/**
318 * alarm_init - Initialize an alarm structure
319 * @alarm: ptr to alarm to be initialized
320 * @type: the type of the alarm
321 * @function: callback that is run when the alarm fires
322 */
323void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
324 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
325{
326 timerqueue_init(&alarm->node);
327 alarm->function = function;
328 alarm->type = type;
329 alarm->state = ALARMTIMER_STATE_INACTIVE;
330}
331
332/**
333 * alarm_start - Sets an alarm to fire
334 * @alarm: ptr to alarm to set
335 * @start: time to run the alarm
336 */
337void alarm_start(struct alarm *alarm, ktime_t start)
338{
339 struct alarm_base *base = &alarm_bases[alarm->type];
340 unsigned long flags;
341
342 spin_lock_irqsave(&base->lock, flags);
343 if (alarmtimer_active(alarm))
344 alarmtimer_remove(base, alarm);
345 alarm->node.expires = start;
346 alarmtimer_enqueue(base, alarm);
347 spin_unlock_irqrestore(&base->lock, flags);
348}
349
350/**
351 * alarm_try_to_cancel - Tries to cancel an alarm timer
352 * @alarm: ptr to alarm to be canceled
353 *
354 * Returns 1 if the timer was canceled, 0 if it was not running,
355 * and -1 if the callback was running
356 */
357int alarm_try_to_cancel(struct alarm *alarm)
358{
359 struct alarm_base *base = &alarm_bases[alarm->type];
360 unsigned long flags;
361 int ret = -1;
362 spin_lock_irqsave(&base->lock, flags);
363
364 if (alarmtimer_callback_running(alarm))
365 goto out;
366
367 if (alarmtimer_is_queued(alarm)) {
368 alarmtimer_remove(base, alarm);
369 ret = 1;
370 } else
371 ret = 0;
372out:
373 spin_unlock_irqrestore(&base->lock, flags);
374 return ret;
375}
376
377
378/**
379 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
380 * @alarm: ptr to alarm to be canceled
381 *
382 * Returns 1 if the timer was canceled, 0 if it was not active.
383 */
384int alarm_cancel(struct alarm *alarm)
385{
386 for (;;) {
387 int ret = alarm_try_to_cancel(alarm);
388 if (ret >= 0)
389 return ret;
390 cpu_relax();
391 }
392}
393
394
395u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
396{
397 u64 overrun = 1;
398 ktime_t delta;
399
400 delta = ktime_sub(now, alarm->node.expires);
401
402 if (delta.tv64 < 0)
403 return 0;
404
405 if (unlikely(delta.tv64 >= interval.tv64)) {
406 s64 incr = ktime_to_ns(interval);
407
408 overrun = ktime_divns(delta, incr);
409
410 alarm->node.expires = ktime_add_ns(alarm->node.expires,
411 incr*overrun);
412
413 if (alarm->node.expires.tv64 > now.tv64)
414 return overrun;
415 /*
416 * This (and the ktime_add() below) is the
417 * correction for exact:
418 */
419 overrun++;
420 }
421
422 alarm->node.expires = ktime_add(alarm->node.expires, interval);
423 return overrun;
424}
425
426
427
428
429/**
430 * clock2alarm - helper that converts from clockid to alarmtypes
431 * @clockid: clockid.
432 */
433static enum alarmtimer_type clock2alarm(clockid_t clockid)
434{
435 if (clockid == CLOCK_REALTIME_ALARM)
436 return ALARM_REALTIME;
437 if (clockid == CLOCK_BOOTTIME_ALARM)
438 return ALARM_BOOTTIME;
439 return -1;
440}
441
442/**
443 * alarm_handle_timer - Callback for posix timers
444 * @alarm: alarm that fired
445 *
446 * Posix timer callback for expired alarm timers.
447 */
448static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
449 ktime_t now)
450{
451 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
452 it.alarm.alarmtimer);
453 if (posix_timer_event(ptr, 0) != 0)
454 ptr->it_overrun++;
455
456 /* Re-add periodic timers */
457 if (ptr->it.alarm.interval.tv64) {
458 ptr->it_overrun += alarm_forward(alarm, now,
459 ptr->it.alarm.interval);
460 return ALARMTIMER_RESTART;
461 }
462 return ALARMTIMER_NORESTART;
463}
464
465/**
466 * alarm_clock_getres - posix getres interface
467 * @which_clock: clockid
468 * @tp: timespec to fill
469 *
470 * Returns the granularity of underlying alarm base clock
471 */
472static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
473{
474 clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
475
476 if (!alarmtimer_get_rtcdev())
477 return -ENOTSUPP;
478
479 return hrtimer_get_res(baseid, tp);
480}
481
482/**
483 * alarm_clock_get - posix clock_get interface
484 * @which_clock: clockid
485 * @tp: timespec to fill.
486 *
487 * Provides the underlying alarm base time.
488 */
489static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
490{
491 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
492
493 if (!alarmtimer_get_rtcdev())
494 return -ENOTSUPP;
495
496 *tp = ktime_to_timespec(base->gettime());
497 return 0;
498}
499
500/**
501 * alarm_timer_create - posix timer_create interface
502 * @new_timer: k_itimer pointer to manage
503 *
504 * Initializes the k_itimer structure.
505 */
506static int alarm_timer_create(struct k_itimer *new_timer)
507{
508 enum alarmtimer_type type;
509 struct alarm_base *base;
510
511 if (!alarmtimer_get_rtcdev())
512 return -ENOTSUPP;
513
514 if (!capable(CAP_WAKE_ALARM))
515 return -EPERM;
516
517 type = clock2alarm(new_timer->it_clock);
518 base = &alarm_bases[type];
519 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
520 return 0;
521}
522
523/**
524 * alarm_timer_get - posix timer_get interface
525 * @new_timer: k_itimer pointer
526 * @cur_setting: itimerspec data to fill
527 *
528 * Copies the itimerspec data out from the k_itimer
529 */
530static void alarm_timer_get(struct k_itimer *timr,
531 struct itimerspec *cur_setting)
532{
533 memset(cur_setting, 0, sizeof(struct itimerspec));
534
535 cur_setting->it_interval =
536 ktime_to_timespec(timr->it.alarm.interval);
537 cur_setting->it_value =
538 ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
539 return;
540}
541
542/**
543 * alarm_timer_del - posix timer_del interface
544 * @timr: k_itimer pointer to be deleted
545 *
546 * Cancels any programmed alarms for the given timer.
547 */
548static int alarm_timer_del(struct k_itimer *timr)
549{
550 if (!rtcdev)
551 return -ENOTSUPP;
552
553 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
554 return TIMER_RETRY;
555
556 return 0;
557}
558
559/**
560 * alarm_timer_set - posix timer_set interface
561 * @timr: k_itimer pointer to be deleted
562 * @flags: timer flags
563 * @new_setting: itimerspec to be used
564 * @old_setting: itimerspec being replaced
565 *
566 * Sets the timer to new_setting, and starts the timer.
567 */
568static int alarm_timer_set(struct k_itimer *timr, int flags,
569 struct itimerspec *new_setting,
570 struct itimerspec *old_setting)
571{
572 if (!rtcdev)
573 return -ENOTSUPP;
574
575 if (old_setting)
576 alarm_timer_get(timr, old_setting);
577
578 /* If the timer was already set, cancel it */
579 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
580 return TIMER_RETRY;
581
582 /* start the timer */
583 timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
584 alarm_start(&timr->it.alarm.alarmtimer,
585 timespec_to_ktime(new_setting->it_value));
586 return 0;
587}
588
589/**
590 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
591 * @alarm: ptr to alarm that fired
592 *
593 * Wakes up the task that set the alarmtimer
594 */
595static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
596 ktime_t now)
597{
598 struct task_struct *task = (struct task_struct *)alarm->data;
599
600 alarm->data = NULL;
601 if (task)
602 wake_up_process(task);
603 return ALARMTIMER_NORESTART;
604}
605
606/**
607 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
608 * @alarm: ptr to alarmtimer
609 * @absexp: absolute expiration time
610 *
611 * Sets the alarm timer and sleeps until it is fired or interrupted.
612 */
613static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
614{
615 alarm->data = (void *)current;
616 do {
617 set_current_state(TASK_INTERRUPTIBLE);
618 alarm_start(alarm, absexp);
619 if (likely(alarm->data))
620 schedule();
621
622 alarm_cancel(alarm);
623 } while (alarm->data && !signal_pending(current));
624
625 __set_current_state(TASK_RUNNING);
626
627 return (alarm->data == NULL);
628}
629
630
631/**
632 * update_rmtp - Update remaining timespec value
633 * @exp: expiration time
634 * @type: timer type
635 * @rmtp: user pointer to remaining timepsec value
636 *
637 * Helper function that fills in rmtp value with time between
638 * now and the exp value
639 */
640static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
641 struct timespec __user *rmtp)
642{
643 struct timespec rmt;
644 ktime_t rem;
645
646 rem = ktime_sub(exp, alarm_bases[type].gettime());
647
648 if (rem.tv64 <= 0)
649 return 0;
650 rmt = ktime_to_timespec(rem);
651
652 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
653 return -EFAULT;
654
655 return 1;
656
657}
658
659/**
660 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
661 * @restart: ptr to restart block
662 *
663 * Handles restarted clock_nanosleep calls
664 */
665static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
666{
667 enum alarmtimer_type type = restart->nanosleep.clockid;
668 ktime_t exp;
669 struct timespec __user *rmtp;
670 struct alarm alarm;
671 int ret = 0;
672
673 exp.tv64 = restart->nanosleep.expires;
674 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
675
676 if (alarmtimer_do_nsleep(&alarm, exp))
677 goto out;
678
679 if (freezing(current))
680 alarmtimer_freezerset(exp, type);
681
682 rmtp = restart->nanosleep.rmtp;
683 if (rmtp) {
684 ret = update_rmtp(exp, type, rmtp);
685 if (ret <= 0)
686 goto out;
687 }
688
689
690 /* The other values in restart are already filled in */
691 ret = -ERESTART_RESTARTBLOCK;
692out:
693 return ret;
694}
695
696/**
697 * alarm_timer_nsleep - alarmtimer nanosleep
698 * @which_clock: clockid
699 * @flags: determins abstime or relative
700 * @tsreq: requested sleep time (abs or rel)
701 * @rmtp: remaining sleep time saved
702 *
703 * Handles clock_nanosleep calls against _ALARM clockids
704 */
705static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
706 struct timespec *tsreq, struct timespec __user *rmtp)
707{
708 enum alarmtimer_type type = clock2alarm(which_clock);
709 struct alarm alarm;
710 ktime_t exp;
711 int ret = 0;
712 struct restart_block *restart;
713
714 if (!alarmtimer_get_rtcdev())
715 return -ENOTSUPP;
716
717 if (!capable(CAP_WAKE_ALARM))
718 return -EPERM;
719
720 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
721
722 exp = timespec_to_ktime(*tsreq);
723 /* Convert (if necessary) to absolute time */
724 if (flags != TIMER_ABSTIME) {
725 ktime_t now = alarm_bases[type].gettime();
726 exp = ktime_add(now, exp);
727 }
728
729 if (alarmtimer_do_nsleep(&alarm, exp))
730 goto out;
731
732 if (freezing(current))
733 alarmtimer_freezerset(exp, type);
734
735 /* abs timers don't set remaining time or restart */
736 if (flags == TIMER_ABSTIME) {
737 ret = -ERESTARTNOHAND;
738 goto out;
739 }
740
741 if (rmtp) {
742 ret = update_rmtp(exp, type, rmtp);
743 if (ret <= 0)
744 goto out;
745 }
746
747 restart = ¤t_thread_info()->restart_block;
748 restart->fn = alarm_timer_nsleep_restart;
749 restart->nanosleep.clockid = type;
750 restart->nanosleep.expires = exp.tv64;
751 restart->nanosleep.rmtp = rmtp;
752 ret = -ERESTART_RESTARTBLOCK;
753
754out:
755 return ret;
756}
757
758
759/* Suspend hook structures */
760static const struct dev_pm_ops alarmtimer_pm_ops = {
761 .suspend = alarmtimer_suspend,
762};
763
764static struct platform_driver alarmtimer_driver = {
765 .driver = {
766 .name = "alarmtimer",
767 .pm = &alarmtimer_pm_ops,
768 }
769};
770
771/**
772 * alarmtimer_init - Initialize alarm timer code
773 *
774 * This function initializes the alarm bases and registers
775 * the posix clock ids.
776 */
777static int __init alarmtimer_init(void)
778{
779 struct platform_device *pdev;
780 int error = 0;
781 int i;
782 struct k_clock alarm_clock = {
783 .clock_getres = alarm_clock_getres,
784 .clock_get = alarm_clock_get,
785 .timer_create = alarm_timer_create,
786 .timer_set = alarm_timer_set,
787 .timer_del = alarm_timer_del,
788 .timer_get = alarm_timer_get,
789 .nsleep = alarm_timer_nsleep,
790 };
791
792 alarmtimer_rtc_timer_init();
793
794 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
795 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
796
797 /* Initialize alarm bases */
798 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
799 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
800 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
801 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
802 for (i = 0; i < ALARM_NUMTYPE; i++) {
803 timerqueue_init_head(&alarm_bases[i].timerqueue);
804 spin_lock_init(&alarm_bases[i].lock);
805 hrtimer_init(&alarm_bases[i].timer,
806 alarm_bases[i].base_clockid,
807 HRTIMER_MODE_ABS);
808 alarm_bases[i].timer.function = alarmtimer_fired;
809 }
810
811 error = alarmtimer_rtc_interface_setup();
812 if (error)
813 return error;
814
815 error = platform_driver_register(&alarmtimer_driver);
816 if (error)
817 goto out_if;
818
819 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
820 if (IS_ERR(pdev)) {
821 error = PTR_ERR(pdev);
822 goto out_drv;
823 }
824 return 0;
825
826out_drv:
827 platform_driver_unregister(&alarmtimer_driver);
828out_if:
829 alarmtimer_rtc_interface_remove();
830 return error;
831}
832device_initcall(alarmtimer_init);
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 */
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}
74
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 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
468 it.alarm.alarmtimer);
469 if (posix_timer_event(ptr, 0) != 0)
470 ptr->it_overrun++;
471
472 /* Re-add periodic timers */
473 if (ptr->it.alarm.interval.tv64) {
474 ptr->it_overrun += alarm_forward(alarm, now,
475 ptr->it.alarm.interval);
476 return ALARMTIMER_RESTART;
477 }
478 return ALARMTIMER_NORESTART;
479}
480
481/**
482 * alarm_clock_getres - posix getres interface
483 * @which_clock: clockid
484 * @tp: timespec to fill
485 *
486 * Returns the granularity of underlying alarm base clock
487 */
488static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
489{
490 clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
491
492 if (!alarmtimer_get_rtcdev())
493 return -EINVAL;
494
495 return hrtimer_get_res(baseid, tp);
496}
497
498/**
499 * alarm_clock_get - posix clock_get interface
500 * @which_clock: clockid
501 * @tp: timespec to fill.
502 *
503 * Provides the underlying alarm base time.
504 */
505static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
506{
507 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
508
509 if (!alarmtimer_get_rtcdev())
510 return -EINVAL;
511
512 *tp = ktime_to_timespec(base->gettime());
513 return 0;
514}
515
516/**
517 * alarm_timer_create - posix timer_create interface
518 * @new_timer: k_itimer pointer to manage
519 *
520 * Initializes the k_itimer structure.
521 */
522static int alarm_timer_create(struct k_itimer *new_timer)
523{
524 enum alarmtimer_type type;
525 struct alarm_base *base;
526
527 if (!alarmtimer_get_rtcdev())
528 return -ENOTSUPP;
529
530 if (!capable(CAP_WAKE_ALARM))
531 return -EPERM;
532
533 type = clock2alarm(new_timer->it_clock);
534 base = &alarm_bases[type];
535 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
536 return 0;
537}
538
539/**
540 * alarm_timer_get - posix timer_get interface
541 * @new_timer: k_itimer pointer
542 * @cur_setting: itimerspec data to fill
543 *
544 * Copies the itimerspec data out from the k_itimer
545 */
546static void alarm_timer_get(struct k_itimer *timr,
547 struct itimerspec *cur_setting)
548{
549 memset(cur_setting, 0, sizeof(struct itimerspec));
550
551 cur_setting->it_interval =
552 ktime_to_timespec(timr->it.alarm.interval);
553 cur_setting->it_value =
554 ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
555 return;
556}
557
558/**
559 * alarm_timer_del - posix timer_del interface
560 * @timr: k_itimer pointer to be deleted
561 *
562 * Cancels any programmed alarms for the given timer.
563 */
564static int alarm_timer_del(struct k_itimer *timr)
565{
566 if (!rtcdev)
567 return -ENOTSUPP;
568
569 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
570 return TIMER_RETRY;
571
572 return 0;
573}
574
575/**
576 * alarm_timer_set - posix timer_set interface
577 * @timr: k_itimer pointer to be deleted
578 * @flags: timer flags
579 * @new_setting: itimerspec to be used
580 * @old_setting: itimerspec being replaced
581 *
582 * Sets the timer to new_setting, and starts the timer.
583 */
584static int alarm_timer_set(struct k_itimer *timr, int flags,
585 struct itimerspec *new_setting,
586 struct itimerspec *old_setting)
587{
588 if (!rtcdev)
589 return -ENOTSUPP;
590
591 if (old_setting)
592 alarm_timer_get(timr, old_setting);
593
594 /* If the timer was already set, cancel it */
595 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
596 return TIMER_RETRY;
597
598 /* start the timer */
599 timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
600 alarm_start(&timr->it.alarm.alarmtimer,
601 timespec_to_ktime(new_setting->it_value));
602 return 0;
603}
604
605/**
606 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
607 * @alarm: ptr to alarm that fired
608 *
609 * Wakes up the task that set the alarmtimer
610 */
611static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
612 ktime_t now)
613{
614 struct task_struct *task = (struct task_struct *)alarm->data;
615
616 alarm->data = NULL;
617 if (task)
618 wake_up_process(task);
619 return ALARMTIMER_NORESTART;
620}
621
622/**
623 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
624 * @alarm: ptr to alarmtimer
625 * @absexp: absolute expiration time
626 *
627 * Sets the alarm timer and sleeps until it is fired or interrupted.
628 */
629static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
630{
631 alarm->data = (void *)current;
632 do {
633 set_current_state(TASK_INTERRUPTIBLE);
634 alarm_start(alarm, absexp);
635 if (likely(alarm->data))
636 schedule();
637
638 alarm_cancel(alarm);
639 } while (alarm->data && !signal_pending(current));
640
641 __set_current_state(TASK_RUNNING);
642
643 return (alarm->data == NULL);
644}
645
646
647/**
648 * update_rmtp - Update remaining timespec value
649 * @exp: expiration time
650 * @type: timer type
651 * @rmtp: user pointer to remaining timepsec value
652 *
653 * Helper function that fills in rmtp value with time between
654 * now and the exp value
655 */
656static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
657 struct timespec __user *rmtp)
658{
659 struct timespec rmt;
660 ktime_t rem;
661
662 rem = ktime_sub(exp, alarm_bases[type].gettime());
663
664 if (rem.tv64 <= 0)
665 return 0;
666 rmt = ktime_to_timespec(rem);
667
668 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
669 return -EFAULT;
670
671 return 1;
672
673}
674
675/**
676 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
677 * @restart: ptr to restart block
678 *
679 * Handles restarted clock_nanosleep calls
680 */
681static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
682{
683 enum alarmtimer_type type = restart->nanosleep.clockid;
684 ktime_t exp;
685 struct timespec __user *rmtp;
686 struct alarm alarm;
687 int ret = 0;
688
689 exp.tv64 = restart->nanosleep.expires;
690 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
691
692 if (alarmtimer_do_nsleep(&alarm, exp))
693 goto out;
694
695 if (freezing(current))
696 alarmtimer_freezerset(exp, type);
697
698 rmtp = restart->nanosleep.rmtp;
699 if (rmtp) {
700 ret = update_rmtp(exp, type, rmtp);
701 if (ret <= 0)
702 goto out;
703 }
704
705
706 /* The other values in restart are already filled in */
707 ret = -ERESTART_RESTARTBLOCK;
708out:
709 return ret;
710}
711
712/**
713 * alarm_timer_nsleep - alarmtimer nanosleep
714 * @which_clock: clockid
715 * @flags: determins abstime or relative
716 * @tsreq: requested sleep time (abs or rel)
717 * @rmtp: remaining sleep time saved
718 *
719 * Handles clock_nanosleep calls against _ALARM clockids
720 */
721static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
722 struct timespec *tsreq, struct timespec __user *rmtp)
723{
724 enum alarmtimer_type type = clock2alarm(which_clock);
725 struct alarm alarm;
726 ktime_t exp;
727 int ret = 0;
728 struct restart_block *restart;
729
730 if (!alarmtimer_get_rtcdev())
731 return -ENOTSUPP;
732
733 if (!capable(CAP_WAKE_ALARM))
734 return -EPERM;
735
736 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
737
738 exp = timespec_to_ktime(*tsreq);
739 /* Convert (if necessary) to absolute time */
740 if (flags != TIMER_ABSTIME) {
741 ktime_t now = alarm_bases[type].gettime();
742 exp = ktime_add(now, exp);
743 }
744
745 if (alarmtimer_do_nsleep(&alarm, exp))
746 goto out;
747
748 if (freezing(current))
749 alarmtimer_freezerset(exp, type);
750
751 /* abs timers don't set remaining time or restart */
752 if (flags == TIMER_ABSTIME) {
753 ret = -ERESTARTNOHAND;
754 goto out;
755 }
756
757 if (rmtp) {
758 ret = update_rmtp(exp, type, rmtp);
759 if (ret <= 0)
760 goto out;
761 }
762
763 restart = ¤t_thread_info()->restart_block;
764 restart->fn = alarm_timer_nsleep_restart;
765 restart->nanosleep.clockid = type;
766 restart->nanosleep.expires = exp.tv64;
767 restart->nanosleep.rmtp = rmtp;
768 ret = -ERESTART_RESTARTBLOCK;
769
770out:
771 return ret;
772}
773
774
775/* Suspend hook structures */
776static const struct dev_pm_ops alarmtimer_pm_ops = {
777 .suspend = alarmtimer_suspend,
778};
779
780static struct platform_driver alarmtimer_driver = {
781 .driver = {
782 .name = "alarmtimer",
783 .pm = &alarmtimer_pm_ops,
784 }
785};
786
787/**
788 * alarmtimer_init - Initialize alarm timer code
789 *
790 * This function initializes the alarm bases and registers
791 * the posix clock ids.
792 */
793static int __init alarmtimer_init(void)
794{
795 struct platform_device *pdev;
796 int error = 0;
797 int i;
798 struct k_clock alarm_clock = {
799 .clock_getres = alarm_clock_getres,
800 .clock_get = alarm_clock_get,
801 .timer_create = alarm_timer_create,
802 .timer_set = alarm_timer_set,
803 .timer_del = alarm_timer_del,
804 .timer_get = alarm_timer_get,
805 .nsleep = alarm_timer_nsleep,
806 };
807
808 alarmtimer_rtc_timer_init();
809
810 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
811 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
812
813 /* Initialize alarm bases */
814 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
815 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
816 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
817 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
818 for (i = 0; i < ALARM_NUMTYPE; i++) {
819 timerqueue_init_head(&alarm_bases[i].timerqueue);
820 spin_lock_init(&alarm_bases[i].lock);
821 }
822
823 error = alarmtimer_rtc_interface_setup();
824 if (error)
825 return error;
826
827 error = platform_driver_register(&alarmtimer_driver);
828 if (error)
829 goto out_if;
830
831 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
832 if (IS_ERR(pdev)) {
833 error = PTR_ERR(pdev);
834 goto out_drv;
835 }
836 ws = wakeup_source_register("alarmtimer");
837 return 0;
838
839out_drv:
840 platform_driver_unregister(&alarmtimer_driver);
841out_if:
842 alarmtimer_rtc_interface_remove();
843 return error;
844}
845device_initcall(alarmtimer_init);