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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#define CREATE_TRACE_POINTS
30#include <trace/events/alarmtimer.h>
31
32/**
33 * struct alarm_base - Alarm timer bases
34 * @lock: Lock for syncrhonized access to the base
35 * @timerqueue: Timerqueue head managing the list of events
36 * @gettime: Function to read the time correlating to the base
37 * @base_clockid: clockid for the base
38 */
39static struct alarm_base {
40 spinlock_t lock;
41 struct timerqueue_head timerqueue;
42 ktime_t (*gettime)(void);
43 clockid_t base_clockid;
44} alarm_bases[ALARM_NUMTYPE];
45
46/* freezer information to handle clock_nanosleep triggered wakeups */
47static enum alarmtimer_type freezer_alarmtype;
48static ktime_t freezer_expires;
49static ktime_t freezer_delta;
50static DEFINE_SPINLOCK(freezer_delta_lock);
51
52static struct wakeup_source *ws;
53
54#ifdef CONFIG_RTC_CLASS
55/* rtc timer and device for setting alarm wakeups at suspend */
56static struct rtc_timer rtctimer;
57static struct rtc_device *rtcdev;
58static DEFINE_SPINLOCK(rtcdev_lock);
59
60/**
61 * alarmtimer_get_rtcdev - Return selected rtcdevice
62 *
63 * This function returns the rtc device to use for wakealarms.
64 * If one has not already been chosen, it checks to see if a
65 * functional rtc device is available.
66 */
67struct rtc_device *alarmtimer_get_rtcdev(void)
68{
69 unsigned long flags;
70 struct rtc_device *ret;
71
72 spin_lock_irqsave(&rtcdev_lock, flags);
73 ret = rtcdev;
74 spin_unlock_irqrestore(&rtcdev_lock, flags);
75
76 return ret;
77}
78EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
79
80static int alarmtimer_rtc_add_device(struct device *dev,
81 struct class_interface *class_intf)
82{
83 unsigned long flags;
84 struct rtc_device *rtc = to_rtc_device(dev);
85
86 if (rtcdev)
87 return -EBUSY;
88
89 if (!rtc->ops->set_alarm)
90 return -1;
91 if (!device_may_wakeup(rtc->dev.parent))
92 return -1;
93
94 spin_lock_irqsave(&rtcdev_lock, flags);
95 if (!rtcdev) {
96 rtcdev = rtc;
97 /* hold a reference so it doesn't go away */
98 get_device(dev);
99 }
100 spin_unlock_irqrestore(&rtcdev_lock, flags);
101 return 0;
102}
103
104static inline void alarmtimer_rtc_timer_init(void)
105{
106 rtc_timer_init(&rtctimer, NULL, NULL);
107}
108
109static struct class_interface alarmtimer_rtc_interface = {
110 .add_dev = &alarmtimer_rtc_add_device,
111};
112
113static int alarmtimer_rtc_interface_setup(void)
114{
115 alarmtimer_rtc_interface.class = rtc_class;
116 return class_interface_register(&alarmtimer_rtc_interface);
117}
118static void alarmtimer_rtc_interface_remove(void)
119{
120 class_interface_unregister(&alarmtimer_rtc_interface);
121}
122#else
123struct rtc_device *alarmtimer_get_rtcdev(void)
124{
125 return NULL;
126}
127#define rtcdev (NULL)
128static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
129static inline void alarmtimer_rtc_interface_remove(void) { }
130static inline void alarmtimer_rtc_timer_init(void) { }
131#endif
132
133/**
134 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
135 * @base: pointer to the base where the timer is being run
136 * @alarm: pointer to alarm being enqueued.
137 *
138 * Adds alarm to a alarm_base timerqueue
139 *
140 * Must hold base->lock when calling.
141 */
142static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
143{
144 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
145 timerqueue_del(&base->timerqueue, &alarm->node);
146
147 timerqueue_add(&base->timerqueue, &alarm->node);
148 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
149}
150
151/**
152 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
153 * @base: pointer to the base where the timer is running
154 * @alarm: pointer to alarm being removed
155 *
156 * Removes alarm to a alarm_base timerqueue
157 *
158 * Must hold base->lock when calling.
159 */
160static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
161{
162 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
163 return;
164
165 timerqueue_del(&base->timerqueue, &alarm->node);
166 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
167}
168
169
170/**
171 * alarmtimer_fired - Handles alarm hrtimer being fired.
172 * @timer: pointer to hrtimer being run
173 *
174 * When a alarm timer fires, this runs through the timerqueue to
175 * see which alarms expired, and runs those. If there are more alarm
176 * timers queued for the future, we set the hrtimer to fire when
177 * when the next future alarm timer expires.
178 */
179static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
180{
181 struct alarm *alarm = container_of(timer, struct alarm, timer);
182 struct alarm_base *base = &alarm_bases[alarm->type];
183 unsigned long flags;
184 int ret = HRTIMER_NORESTART;
185 int restart = ALARMTIMER_NORESTART;
186
187 spin_lock_irqsave(&base->lock, flags);
188 alarmtimer_dequeue(base, alarm);
189 spin_unlock_irqrestore(&base->lock, flags);
190
191 if (alarm->function)
192 restart = alarm->function(alarm, base->gettime());
193
194 spin_lock_irqsave(&base->lock, flags);
195 if (restart != ALARMTIMER_NORESTART) {
196 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
197 alarmtimer_enqueue(base, alarm);
198 ret = HRTIMER_RESTART;
199 }
200 spin_unlock_irqrestore(&base->lock, flags);
201
202 trace_alarmtimer_fired(alarm, base->gettime());
203 return ret;
204
205}
206
207ktime_t alarm_expires_remaining(const struct alarm *alarm)
208{
209 struct alarm_base *base = &alarm_bases[alarm->type];
210 return ktime_sub(alarm->node.expires, base->gettime());
211}
212EXPORT_SYMBOL_GPL(alarm_expires_remaining);
213
214#ifdef CONFIG_RTC_CLASS
215/**
216 * alarmtimer_suspend - Suspend time callback
217 * @dev: unused
218 * @state: unused
219 *
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.
224 */
225static int alarmtimer_suspend(struct device *dev)
226{
227 ktime_t min, now, expires;
228 int i, ret, type;
229 struct rtc_device *rtc;
230 unsigned long flags;
231 struct rtc_time tm;
232
233 spin_lock_irqsave(&freezer_delta_lock, flags);
234 min = freezer_delta;
235 expires = freezer_expires;
236 type = freezer_alarmtype;
237 freezer_delta = 0;
238 spin_unlock_irqrestore(&freezer_delta_lock, flags);
239
240 rtc = alarmtimer_get_rtcdev();
241 /* If we have no rtcdev, just return */
242 if (!rtc)
243 return 0;
244
245 /* Find the soonest timer to expire*/
246 for (i = 0; i < ALARM_NUMTYPE; i++) {
247 struct alarm_base *base = &alarm_bases[i];
248 struct timerqueue_node *next;
249 ktime_t delta;
250
251 spin_lock_irqsave(&base->lock, flags);
252 next = timerqueue_getnext(&base->timerqueue);
253 spin_unlock_irqrestore(&base->lock, flags);
254 if (!next)
255 continue;
256 delta = ktime_sub(next->expires, base->gettime());
257 if (!min || (delta < min)) {
258 expires = next->expires;
259 min = delta;
260 type = i;
261 }
262 }
263 if (min == 0)
264 return 0;
265
266 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
267 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
268 return -EBUSY;
269 }
270
271 trace_alarmtimer_suspend(expires, type);
272
273 /* Setup an rtc timer to fire that far in the future */
274 rtc_timer_cancel(rtc, &rtctimer);
275 rtc_read_time(rtc, &tm);
276 now = rtc_tm_to_ktime(tm);
277 now = ktime_add(now, min);
278
279 /* Set alarm, if in the past reject suspend briefly to handle */
280 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
281 if (ret < 0)
282 __pm_wakeup_event(ws, MSEC_PER_SEC);
283 return ret;
284}
285
286static int alarmtimer_resume(struct device *dev)
287{
288 struct rtc_device *rtc;
289
290 rtc = alarmtimer_get_rtcdev();
291 if (rtc)
292 rtc_timer_cancel(rtc, &rtctimer);
293 return 0;
294}
295
296#else
297static int alarmtimer_suspend(struct device *dev)
298{
299 return 0;
300}
301
302static int alarmtimer_resume(struct device *dev)
303{
304 return 0;
305}
306#endif
307
308static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
309{
310 struct alarm_base *base;
311 unsigned long flags;
312 ktime_t delta;
313
314 switch(type) {
315 case ALARM_REALTIME:
316 base = &alarm_bases[ALARM_REALTIME];
317 type = ALARM_REALTIME_FREEZER;
318 break;
319 case ALARM_BOOTTIME:
320 base = &alarm_bases[ALARM_BOOTTIME];
321 type = ALARM_BOOTTIME_FREEZER;
322 break;
323 default:
324 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
325 return;
326 }
327
328 delta = ktime_sub(absexp, base->gettime());
329
330 spin_lock_irqsave(&freezer_delta_lock, flags);
331 if (!freezer_delta || (delta < freezer_delta)) {
332 freezer_delta = delta;
333 freezer_expires = absexp;
334 freezer_alarmtype = type;
335 }
336 spin_unlock_irqrestore(&freezer_delta_lock, flags);
337}
338
339
340/**
341 * alarm_init - Initialize an alarm structure
342 * @alarm: ptr to alarm to be initialized
343 * @type: the type of the alarm
344 * @function: callback that is run when the alarm fires
345 */
346void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
347 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
348{
349 timerqueue_init(&alarm->node);
350 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
351 HRTIMER_MODE_ABS);
352 alarm->timer.function = alarmtimer_fired;
353 alarm->function = function;
354 alarm->type = type;
355 alarm->state = ALARMTIMER_STATE_INACTIVE;
356}
357EXPORT_SYMBOL_GPL(alarm_init);
358
359/**
360 * alarm_start - Sets an absolute alarm to fire
361 * @alarm: ptr to alarm to set
362 * @start: time to run the alarm
363 */
364void alarm_start(struct alarm *alarm, ktime_t start)
365{
366 struct alarm_base *base = &alarm_bases[alarm->type];
367 unsigned long flags;
368
369 spin_lock_irqsave(&base->lock, flags);
370 alarm->node.expires = start;
371 alarmtimer_enqueue(base, alarm);
372 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
373 spin_unlock_irqrestore(&base->lock, flags);
374
375 trace_alarmtimer_start(alarm, base->gettime());
376}
377EXPORT_SYMBOL_GPL(alarm_start);
378
379/**
380 * alarm_start_relative - Sets a relative alarm to fire
381 * @alarm: ptr to alarm to set
382 * @start: time relative to now to run the alarm
383 */
384void alarm_start_relative(struct alarm *alarm, ktime_t start)
385{
386 struct alarm_base *base = &alarm_bases[alarm->type];
387
388 start = ktime_add(start, base->gettime());
389 alarm_start(alarm, start);
390}
391EXPORT_SYMBOL_GPL(alarm_start_relative);
392
393void alarm_restart(struct alarm *alarm)
394{
395 struct alarm_base *base = &alarm_bases[alarm->type];
396 unsigned long flags;
397
398 spin_lock_irqsave(&base->lock, flags);
399 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
400 hrtimer_restart(&alarm->timer);
401 alarmtimer_enqueue(base, alarm);
402 spin_unlock_irqrestore(&base->lock, flags);
403}
404EXPORT_SYMBOL_GPL(alarm_restart);
405
406/**
407 * alarm_try_to_cancel - Tries to cancel an alarm timer
408 * @alarm: ptr to alarm to be canceled
409 *
410 * Returns 1 if the timer was canceled, 0 if it was not running,
411 * and -1 if the callback was running
412 */
413int alarm_try_to_cancel(struct alarm *alarm)
414{
415 struct alarm_base *base = &alarm_bases[alarm->type];
416 unsigned long flags;
417 int ret;
418
419 spin_lock_irqsave(&base->lock, flags);
420 ret = hrtimer_try_to_cancel(&alarm->timer);
421 if (ret >= 0)
422 alarmtimer_dequeue(base, alarm);
423 spin_unlock_irqrestore(&base->lock, flags);
424
425 trace_alarmtimer_cancel(alarm, base->gettime());
426 return ret;
427}
428EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
429
430
431/**
432 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
433 * @alarm: ptr to alarm to be canceled
434 *
435 * Returns 1 if the timer was canceled, 0 if it was not active.
436 */
437int alarm_cancel(struct alarm *alarm)
438{
439 for (;;) {
440 int ret = alarm_try_to_cancel(alarm);
441 if (ret >= 0)
442 return ret;
443 cpu_relax();
444 }
445}
446EXPORT_SYMBOL_GPL(alarm_cancel);
447
448
449u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
450{
451 u64 overrun = 1;
452 ktime_t delta;
453
454 delta = ktime_sub(now, alarm->node.expires);
455
456 if (delta < 0)
457 return 0;
458
459 if (unlikely(delta >= interval)) {
460 s64 incr = ktime_to_ns(interval);
461
462 overrun = ktime_divns(delta, incr);
463
464 alarm->node.expires = ktime_add_ns(alarm->node.expires,
465 incr*overrun);
466
467 if (alarm->node.expires > now)
468 return overrun;
469 /*
470 * This (and the ktime_add() below) is the
471 * correction for exact:
472 */
473 overrun++;
474 }
475
476 alarm->node.expires = ktime_add(alarm->node.expires, interval);
477 return overrun;
478}
479EXPORT_SYMBOL_GPL(alarm_forward);
480
481u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
482{
483 struct alarm_base *base = &alarm_bases[alarm->type];
484
485 return alarm_forward(alarm, base->gettime(), interval);
486}
487EXPORT_SYMBOL_GPL(alarm_forward_now);
488
489
490/**
491 * clock2alarm - helper that converts from clockid to alarmtypes
492 * @clockid: clockid.
493 */
494static enum alarmtimer_type clock2alarm(clockid_t clockid)
495{
496 if (clockid == CLOCK_REALTIME_ALARM)
497 return ALARM_REALTIME;
498 if (clockid == CLOCK_BOOTTIME_ALARM)
499 return ALARM_BOOTTIME;
500 return -1;
501}
502
503/**
504 * alarm_handle_timer - Callback for posix timers
505 * @alarm: alarm that fired
506 *
507 * Posix timer callback for expired alarm timers.
508 */
509static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
510 ktime_t now)
511{
512 unsigned long flags;
513 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
514 it.alarm.alarmtimer);
515 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
516
517 spin_lock_irqsave(&ptr->it_lock, flags);
518 if ((ptr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) {
519 if (IS_ENABLED(CONFIG_POSIX_TIMERS) &&
520 posix_timer_event(ptr, 0) != 0)
521 ptr->it_overrun++;
522 }
523
524 /* Re-add periodic timers */
525 if (ptr->it.alarm.interval) {
526 ptr->it_overrun += alarm_forward(alarm, now,
527 ptr->it.alarm.interval);
528 result = ALARMTIMER_RESTART;
529 }
530 spin_unlock_irqrestore(&ptr->it_lock, flags);
531
532 return result;
533}
534
535/**
536 * alarm_clock_getres - posix getres interface
537 * @which_clock: clockid
538 * @tp: timespec to fill
539 *
540 * Returns the granularity of underlying alarm base clock
541 */
542static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
543{
544 if (!alarmtimer_get_rtcdev())
545 return -EINVAL;
546
547 tp->tv_sec = 0;
548 tp->tv_nsec = hrtimer_resolution;
549 return 0;
550}
551
552/**
553 * alarm_clock_get - posix clock_get interface
554 * @which_clock: clockid
555 * @tp: timespec to fill.
556 *
557 * Provides the underlying alarm base time.
558 */
559static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
560{
561 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
562
563 if (!alarmtimer_get_rtcdev())
564 return -EINVAL;
565
566 *tp = ktime_to_timespec(base->gettime());
567 return 0;
568}
569
570/**
571 * alarm_timer_create - posix timer_create interface
572 * @new_timer: k_itimer pointer to manage
573 *
574 * Initializes the k_itimer structure.
575 */
576static int alarm_timer_create(struct k_itimer *new_timer)
577{
578 enum alarmtimer_type type;
579
580 if (!alarmtimer_get_rtcdev())
581 return -ENOTSUPP;
582
583 if (!capable(CAP_WAKE_ALARM))
584 return -EPERM;
585
586 type = clock2alarm(new_timer->it_clock);
587 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
588 return 0;
589}
590
591/**
592 * alarm_timer_get - posix timer_get interface
593 * @new_timer: k_itimer pointer
594 * @cur_setting: itimerspec data to fill
595 *
596 * Copies out the current itimerspec data
597 */
598static void alarm_timer_get(struct k_itimer *timr,
599 struct itimerspec *cur_setting)
600{
601 ktime_t relative_expiry_time =
602 alarm_expires_remaining(&(timr->it.alarm.alarmtimer));
603
604 if (ktime_to_ns(relative_expiry_time) > 0) {
605 cur_setting->it_value = ktime_to_timespec(relative_expiry_time);
606 } else {
607 cur_setting->it_value.tv_sec = 0;
608 cur_setting->it_value.tv_nsec = 0;
609 }
610
611 cur_setting->it_interval = ktime_to_timespec(timr->it.alarm.interval);
612}
613
614/**
615 * alarm_timer_del - posix timer_del interface
616 * @timr: k_itimer pointer to be deleted
617 *
618 * Cancels any programmed alarms for the given timer.
619 */
620static int alarm_timer_del(struct k_itimer *timr)
621{
622 if (!rtcdev)
623 return -ENOTSUPP;
624
625 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
626 return TIMER_RETRY;
627
628 return 0;
629}
630
631/**
632 * alarm_timer_set - posix timer_set interface
633 * @timr: k_itimer pointer to be deleted
634 * @flags: timer flags
635 * @new_setting: itimerspec to be used
636 * @old_setting: itimerspec being replaced
637 *
638 * Sets the timer to new_setting, and starts the timer.
639 */
640static int alarm_timer_set(struct k_itimer *timr, int flags,
641 struct itimerspec *new_setting,
642 struct itimerspec *old_setting)
643{
644 ktime_t exp;
645
646 if (!rtcdev)
647 return -ENOTSUPP;
648
649 if (flags & ~TIMER_ABSTIME)
650 return -EINVAL;
651
652 if (old_setting)
653 alarm_timer_get(timr, old_setting);
654
655 /* If the timer was already set, cancel it */
656 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
657 return TIMER_RETRY;
658
659 /* start the timer */
660 timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
661 exp = timespec_to_ktime(new_setting->it_value);
662 /* Convert (if necessary) to absolute time */
663 if (flags != TIMER_ABSTIME) {
664 ktime_t now;
665
666 now = alarm_bases[timr->it.alarm.alarmtimer.type].gettime();
667 exp = ktime_add(now, exp);
668 }
669
670 alarm_start(&timr->it.alarm.alarmtimer, exp);
671 return 0;
672}
673
674/**
675 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
676 * @alarm: ptr to alarm that fired
677 *
678 * Wakes up the task that set the alarmtimer
679 */
680static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
681 ktime_t now)
682{
683 struct task_struct *task = (struct task_struct *)alarm->data;
684
685 alarm->data = NULL;
686 if (task)
687 wake_up_process(task);
688 return ALARMTIMER_NORESTART;
689}
690
691/**
692 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
693 * @alarm: ptr to alarmtimer
694 * @absexp: absolute expiration time
695 *
696 * Sets the alarm timer and sleeps until it is fired or interrupted.
697 */
698static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
699{
700 alarm->data = (void *)current;
701 do {
702 set_current_state(TASK_INTERRUPTIBLE);
703 alarm_start(alarm, absexp);
704 if (likely(alarm->data))
705 schedule();
706
707 alarm_cancel(alarm);
708 } while (alarm->data && !signal_pending(current));
709
710 __set_current_state(TASK_RUNNING);
711
712 return (alarm->data == NULL);
713}
714
715
716/**
717 * update_rmtp - Update remaining timespec value
718 * @exp: expiration time
719 * @type: timer type
720 * @rmtp: user pointer to remaining timepsec value
721 *
722 * Helper function that fills in rmtp value with time between
723 * now and the exp value
724 */
725static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
726 struct timespec __user *rmtp)
727{
728 struct timespec rmt;
729 ktime_t rem;
730
731 rem = ktime_sub(exp, alarm_bases[type].gettime());
732
733 if (rem <= 0)
734 return 0;
735 rmt = ktime_to_timespec(rem);
736
737 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
738 return -EFAULT;
739
740 return 1;
741
742}
743
744/**
745 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
746 * @restart: ptr to restart block
747 *
748 * Handles restarted clock_nanosleep calls
749 */
750static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
751{
752 enum alarmtimer_type type = restart->nanosleep.clockid;
753 ktime_t exp;
754 struct timespec __user *rmtp;
755 struct alarm alarm;
756 int ret = 0;
757
758 exp = restart->nanosleep.expires;
759 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
760
761 if (alarmtimer_do_nsleep(&alarm, exp))
762 goto out;
763
764 if (freezing(current))
765 alarmtimer_freezerset(exp, type);
766
767 rmtp = restart->nanosleep.rmtp;
768 if (rmtp) {
769 ret = update_rmtp(exp, type, rmtp);
770 if (ret <= 0)
771 goto out;
772 }
773
774
775 /* The other values in restart are already filled in */
776 ret = -ERESTART_RESTARTBLOCK;
777out:
778 return ret;
779}
780
781/**
782 * alarm_timer_nsleep - alarmtimer nanosleep
783 * @which_clock: clockid
784 * @flags: determins abstime or relative
785 * @tsreq: requested sleep time (abs or rel)
786 * @rmtp: remaining sleep time saved
787 *
788 * Handles clock_nanosleep calls against _ALARM clockids
789 */
790static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
791 struct timespec *tsreq, struct timespec __user *rmtp)
792{
793 enum alarmtimer_type type = clock2alarm(which_clock);
794 struct alarm alarm;
795 ktime_t exp;
796 int ret = 0;
797 struct restart_block *restart;
798
799 if (!alarmtimer_get_rtcdev())
800 return -ENOTSUPP;
801
802 if (flags & ~TIMER_ABSTIME)
803 return -EINVAL;
804
805 if (!capable(CAP_WAKE_ALARM))
806 return -EPERM;
807
808 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
809
810 exp = timespec_to_ktime(*tsreq);
811 /* Convert (if necessary) to absolute time */
812 if (flags != TIMER_ABSTIME) {
813 ktime_t now = alarm_bases[type].gettime();
814 exp = ktime_add(now, exp);
815 }
816
817 if (alarmtimer_do_nsleep(&alarm, exp))
818 goto out;
819
820 if (freezing(current))
821 alarmtimer_freezerset(exp, type);
822
823 /* abs timers don't set remaining time or restart */
824 if (flags == TIMER_ABSTIME) {
825 ret = -ERESTARTNOHAND;
826 goto out;
827 }
828
829 if (rmtp) {
830 ret = update_rmtp(exp, type, rmtp);
831 if (ret <= 0)
832 goto out;
833 }
834
835 restart = ¤t->restart_block;
836 restart->fn = alarm_timer_nsleep_restart;
837 restart->nanosleep.clockid = type;
838 restart->nanosleep.expires = exp;
839 restart->nanosleep.rmtp = rmtp;
840 ret = -ERESTART_RESTARTBLOCK;
841
842out:
843 return ret;
844}
845
846
847/* Suspend hook structures */
848static const struct dev_pm_ops alarmtimer_pm_ops = {
849 .suspend = alarmtimer_suspend,
850 .resume = alarmtimer_resume,
851};
852
853static struct platform_driver alarmtimer_driver = {
854 .driver = {
855 .name = "alarmtimer",
856 .pm = &alarmtimer_pm_ops,
857 }
858};
859
860/**
861 * alarmtimer_init - Initialize alarm timer code
862 *
863 * This function initializes the alarm bases and registers
864 * the posix clock ids.
865 */
866static int __init alarmtimer_init(void)
867{
868 struct platform_device *pdev;
869 int error = 0;
870 int i;
871 struct k_clock alarm_clock = {
872 .clock_getres = alarm_clock_getres,
873 .clock_get = alarm_clock_get,
874 .timer_create = alarm_timer_create,
875 .timer_set = alarm_timer_set,
876 .timer_del = alarm_timer_del,
877 .timer_get = alarm_timer_get,
878 .nsleep = alarm_timer_nsleep,
879 };
880
881 alarmtimer_rtc_timer_init();
882
883 if (IS_ENABLED(CONFIG_POSIX_TIMERS)) {
884 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
885 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
886 }
887
888 /* Initialize alarm bases */
889 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
890 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
891 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
892 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
893 for (i = 0; i < ALARM_NUMTYPE; i++) {
894 timerqueue_init_head(&alarm_bases[i].timerqueue);
895 spin_lock_init(&alarm_bases[i].lock);
896 }
897
898 error = alarmtimer_rtc_interface_setup();
899 if (error)
900 return error;
901
902 error = platform_driver_register(&alarmtimer_driver);
903 if (error)
904 goto out_if;
905
906 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
907 if (IS_ERR(pdev)) {
908 error = PTR_ERR(pdev);
909 goto out_drv;
910 }
911 ws = wakeup_source_register("alarmtimer");
912 return 0;
913
914out_drv:
915 platform_driver_unregister(&alarmtimer_driver);
916out_if:
917 alarmtimer_rtc_interface_remove();
918 return error;
919}
920device_initcall(alarmtimer_init);