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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * Alarmtimer interface
4 *
5 * This interface provides a timer which is similar to hrtimers,
6 * but triggers a RTC alarm if the box is suspend.
7 *
8 * This interface is influenced by the Android RTC Alarm timer
9 * interface.
10 *
11 * Copyright (C) 2010 IBM Corporation
12 *
13 * Author: John Stultz <john.stultz@linaro.org>
14 */
15#include <linux/time.h>
16#include <linux/hrtimer.h>
17#include <linux/timerqueue.h>
18#include <linux/rtc.h>
19#include <linux/sched/signal.h>
20#include <linux/sched/debug.h>
21#include <linux/alarmtimer.h>
22#include <linux/mutex.h>
23#include <linux/platform_device.h>
24#include <linux/posix-timers.h>
25#include <linux/workqueue.h>
26#include <linux/freezer.h>
27#include <linux/compat.h>
28#include <linux/module.h>
29#include <linux/time_namespace.h>
30
31#include "posix-timers.h"
32
33#define CREATE_TRACE_POINTS
34#include <trace/events/alarmtimer.h>
35
36/**
37 * struct alarm_base - Alarm timer bases
38 * @lock: Lock for syncrhonized access to the base
39 * @timerqueue: Timerqueue head managing the list of events
40 * @get_ktime: Function to read the time correlating to the base
41 * @get_timespec: Function to read the namespace time correlating to the base
42 * @base_clockid: clockid for the base
43 */
44static struct alarm_base {
45 spinlock_t lock;
46 struct timerqueue_head timerqueue;
47 ktime_t (*get_ktime)(void);
48 void (*get_timespec)(struct timespec64 *tp);
49 clockid_t base_clockid;
50} alarm_bases[ALARM_NUMTYPE];
51
52#if defined(CONFIG_POSIX_TIMERS) || defined(CONFIG_RTC_CLASS)
53/* freezer information to handle clock_nanosleep triggered wakeups */
54static enum alarmtimer_type freezer_alarmtype;
55static ktime_t freezer_expires;
56static ktime_t freezer_delta;
57static DEFINE_SPINLOCK(freezer_delta_lock);
58#endif
59
60#ifdef CONFIG_RTC_CLASS
61/* rtc timer and device for setting alarm wakeups at suspend */
62static struct rtc_timer rtctimer;
63static struct rtc_device *rtcdev;
64static DEFINE_SPINLOCK(rtcdev_lock);
65
66/**
67 * alarmtimer_get_rtcdev - Return selected rtcdevice
68 *
69 * This function returns the rtc device to use for wakealarms.
70 */
71struct rtc_device *alarmtimer_get_rtcdev(void)
72{
73 unsigned long flags;
74 struct rtc_device *ret;
75
76 spin_lock_irqsave(&rtcdev_lock, flags);
77 ret = rtcdev;
78 spin_unlock_irqrestore(&rtcdev_lock, flags);
79
80 return ret;
81}
82EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
83
84static int alarmtimer_rtc_add_device(struct device *dev,
85 struct class_interface *class_intf)
86{
87 unsigned long flags;
88 struct rtc_device *rtc = to_rtc_device(dev);
89 struct platform_device *pdev;
90 int ret = 0;
91
92 if (rtcdev)
93 return -EBUSY;
94
95 if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
96 return -1;
97 if (!device_may_wakeup(rtc->dev.parent))
98 return -1;
99
100 pdev = platform_device_register_data(dev, "alarmtimer",
101 PLATFORM_DEVID_AUTO, NULL, 0);
102 if (!IS_ERR(pdev))
103 device_init_wakeup(&pdev->dev, true);
104
105 spin_lock_irqsave(&rtcdev_lock, flags);
106 if (!IS_ERR(pdev) && !rtcdev) {
107 if (!try_module_get(rtc->owner)) {
108 ret = -1;
109 goto unlock;
110 }
111
112 rtcdev = rtc;
113 /* hold a reference so it doesn't go away */
114 get_device(dev);
115 pdev = NULL;
116 } else {
117 ret = -1;
118 }
119unlock:
120 spin_unlock_irqrestore(&rtcdev_lock, flags);
121
122 platform_device_unregister(pdev);
123
124 return ret;
125}
126
127static inline void alarmtimer_rtc_timer_init(void)
128{
129 rtc_timer_init(&rtctimer, NULL, NULL);
130}
131
132static struct class_interface alarmtimer_rtc_interface = {
133 .add_dev = &alarmtimer_rtc_add_device,
134};
135
136static int alarmtimer_rtc_interface_setup(void)
137{
138 alarmtimer_rtc_interface.class = rtc_class;
139 return class_interface_register(&alarmtimer_rtc_interface);
140}
141static void alarmtimer_rtc_interface_remove(void)
142{
143 class_interface_unregister(&alarmtimer_rtc_interface);
144}
145#else
146static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
147static inline void alarmtimer_rtc_interface_remove(void) { }
148static inline void alarmtimer_rtc_timer_init(void) { }
149#endif
150
151/**
152 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
153 * @base: pointer to the base where the timer is being run
154 * @alarm: pointer to alarm being enqueued.
155 *
156 * Adds alarm to a alarm_base timerqueue
157 *
158 * Must hold base->lock when calling.
159 */
160static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
161{
162 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
163 timerqueue_del(&base->timerqueue, &alarm->node);
164
165 timerqueue_add(&base->timerqueue, &alarm->node);
166 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
167}
168
169/**
170 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
171 * @base: pointer to the base where the timer is running
172 * @alarm: pointer to alarm being removed
173 *
174 * Removes alarm to a alarm_base timerqueue
175 *
176 * Must hold base->lock when calling.
177 */
178static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
179{
180 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
181 return;
182
183 timerqueue_del(&base->timerqueue, &alarm->node);
184 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
185}
186
187
188/**
189 * alarmtimer_fired - Handles alarm hrtimer being fired.
190 * @timer: pointer to hrtimer being run
191 *
192 * When a alarm timer fires, this runs through the timerqueue to
193 * see which alarms expired, and runs those. If there are more alarm
194 * timers queued for the future, we set the hrtimer to fire when
195 * the next future alarm timer expires.
196 */
197static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
198{
199 struct alarm *alarm = container_of(timer, struct alarm, timer);
200 struct alarm_base *base = &alarm_bases[alarm->type];
201 unsigned long flags;
202 int ret = HRTIMER_NORESTART;
203 int restart = ALARMTIMER_NORESTART;
204
205 spin_lock_irqsave(&base->lock, flags);
206 alarmtimer_dequeue(base, alarm);
207 spin_unlock_irqrestore(&base->lock, flags);
208
209 if (alarm->function)
210 restart = alarm->function(alarm, base->get_ktime());
211
212 spin_lock_irqsave(&base->lock, flags);
213 if (restart != ALARMTIMER_NORESTART) {
214 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
215 alarmtimer_enqueue(base, alarm);
216 ret = HRTIMER_RESTART;
217 }
218 spin_unlock_irqrestore(&base->lock, flags);
219
220 trace_alarmtimer_fired(alarm, base->get_ktime());
221 return ret;
222
223}
224
225ktime_t alarm_expires_remaining(const struct alarm *alarm)
226{
227 struct alarm_base *base = &alarm_bases[alarm->type];
228 return ktime_sub(alarm->node.expires, base->get_ktime());
229}
230EXPORT_SYMBOL_GPL(alarm_expires_remaining);
231
232#ifdef CONFIG_RTC_CLASS
233/**
234 * alarmtimer_suspend - Suspend time callback
235 * @dev: unused
236 *
237 * When we are going into suspend, we look through the bases
238 * to see which is the soonest timer to expire. We then
239 * set an rtc timer to fire that far into the future, which
240 * will wake us from suspend.
241 */
242static int alarmtimer_suspend(struct device *dev)
243{
244 ktime_t min, now, expires;
245 int i, ret, type;
246 struct rtc_device *rtc;
247 unsigned long flags;
248 struct rtc_time tm;
249
250 spin_lock_irqsave(&freezer_delta_lock, flags);
251 min = freezer_delta;
252 expires = freezer_expires;
253 type = freezer_alarmtype;
254 freezer_delta = 0;
255 spin_unlock_irqrestore(&freezer_delta_lock, flags);
256
257 rtc = alarmtimer_get_rtcdev();
258 /* If we have no rtcdev, just return */
259 if (!rtc)
260 return 0;
261
262 /* Find the soonest timer to expire*/
263 for (i = 0; i < ALARM_NUMTYPE; i++) {
264 struct alarm_base *base = &alarm_bases[i];
265 struct timerqueue_node *next;
266 ktime_t delta;
267
268 spin_lock_irqsave(&base->lock, flags);
269 next = timerqueue_getnext(&base->timerqueue);
270 spin_unlock_irqrestore(&base->lock, flags);
271 if (!next)
272 continue;
273 delta = ktime_sub(next->expires, base->get_ktime());
274 if (!min || (delta < min)) {
275 expires = next->expires;
276 min = delta;
277 type = i;
278 }
279 }
280 if (min == 0)
281 return 0;
282
283 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
284 pm_wakeup_event(dev, 2 * MSEC_PER_SEC);
285 return -EBUSY;
286 }
287
288 trace_alarmtimer_suspend(expires, type);
289
290 /* Setup an rtc timer to fire that far in the future */
291 rtc_timer_cancel(rtc, &rtctimer);
292 rtc_read_time(rtc, &tm);
293 now = rtc_tm_to_ktime(tm);
294 now = ktime_add(now, min);
295
296 /* Set alarm, if in the past reject suspend briefly to handle */
297 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
298 if (ret < 0)
299 pm_wakeup_event(dev, MSEC_PER_SEC);
300 return ret;
301}
302
303static int alarmtimer_resume(struct device *dev)
304{
305 struct rtc_device *rtc;
306
307 rtc = alarmtimer_get_rtcdev();
308 if (rtc)
309 rtc_timer_cancel(rtc, &rtctimer);
310 return 0;
311}
312
313#else
314static int alarmtimer_suspend(struct device *dev)
315{
316 return 0;
317}
318
319static int alarmtimer_resume(struct device *dev)
320{
321 return 0;
322}
323#endif
324
325static void
326__alarm_init(struct alarm *alarm, enum alarmtimer_type type,
327 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
328{
329 timerqueue_init(&alarm->node);
330 alarm->timer.function = alarmtimer_fired;
331 alarm->function = function;
332 alarm->type = type;
333 alarm->state = ALARMTIMER_STATE_INACTIVE;
334}
335
336/**
337 * alarm_init - Initialize an alarm structure
338 * @alarm: ptr to alarm to be initialized
339 * @type: the type of the alarm
340 * @function: callback that is run when the alarm fires
341 */
342void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
343 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
344{
345 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
346 HRTIMER_MODE_ABS);
347 __alarm_init(alarm, type, function);
348}
349EXPORT_SYMBOL_GPL(alarm_init);
350
351/**
352 * alarm_start - Sets an absolute alarm to fire
353 * @alarm: ptr to alarm to set
354 * @start: time to run the alarm
355 */
356void alarm_start(struct alarm *alarm, ktime_t start)
357{
358 struct alarm_base *base = &alarm_bases[alarm->type];
359 unsigned long flags;
360
361 spin_lock_irqsave(&base->lock, flags);
362 alarm->node.expires = start;
363 alarmtimer_enqueue(base, alarm);
364 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
365 spin_unlock_irqrestore(&base->lock, flags);
366
367 trace_alarmtimer_start(alarm, base->get_ktime());
368}
369EXPORT_SYMBOL_GPL(alarm_start);
370
371/**
372 * alarm_start_relative - Sets a relative alarm to fire
373 * @alarm: ptr to alarm to set
374 * @start: time relative to now to run the alarm
375 */
376void alarm_start_relative(struct alarm *alarm, ktime_t start)
377{
378 struct alarm_base *base = &alarm_bases[alarm->type];
379
380 start = ktime_add_safe(start, base->get_ktime());
381 alarm_start(alarm, start);
382}
383EXPORT_SYMBOL_GPL(alarm_start_relative);
384
385void alarm_restart(struct alarm *alarm)
386{
387 struct alarm_base *base = &alarm_bases[alarm->type];
388 unsigned long flags;
389
390 spin_lock_irqsave(&base->lock, flags);
391 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
392 hrtimer_restart(&alarm->timer);
393 alarmtimer_enqueue(base, alarm);
394 spin_unlock_irqrestore(&base->lock, flags);
395}
396EXPORT_SYMBOL_GPL(alarm_restart);
397
398/**
399 * alarm_try_to_cancel - Tries to cancel an alarm timer
400 * @alarm: ptr to alarm to be canceled
401 *
402 * Returns 1 if the timer was canceled, 0 if it was not running,
403 * and -1 if the callback was running
404 */
405int alarm_try_to_cancel(struct alarm *alarm)
406{
407 struct alarm_base *base = &alarm_bases[alarm->type];
408 unsigned long flags;
409 int ret;
410
411 spin_lock_irqsave(&base->lock, flags);
412 ret = hrtimer_try_to_cancel(&alarm->timer);
413 if (ret >= 0)
414 alarmtimer_dequeue(base, alarm);
415 spin_unlock_irqrestore(&base->lock, flags);
416
417 trace_alarmtimer_cancel(alarm, base->get_ktime());
418 return ret;
419}
420EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
421
422
423/**
424 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
425 * @alarm: ptr to alarm to be canceled
426 *
427 * Returns 1 if the timer was canceled, 0 if it was not active.
428 */
429int alarm_cancel(struct alarm *alarm)
430{
431 for (;;) {
432 int ret = alarm_try_to_cancel(alarm);
433 if (ret >= 0)
434 return ret;
435 hrtimer_cancel_wait_running(&alarm->timer);
436 }
437}
438EXPORT_SYMBOL_GPL(alarm_cancel);
439
440
441u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
442{
443 u64 overrun = 1;
444 ktime_t delta;
445
446 delta = ktime_sub(now, alarm->node.expires);
447
448 if (delta < 0)
449 return 0;
450
451 if (unlikely(delta >= interval)) {
452 s64 incr = ktime_to_ns(interval);
453
454 overrun = ktime_divns(delta, incr);
455
456 alarm->node.expires = ktime_add_ns(alarm->node.expires,
457 incr*overrun);
458
459 if (alarm->node.expires > now)
460 return overrun;
461 /*
462 * This (and the ktime_add() below) is the
463 * correction for exact:
464 */
465 overrun++;
466 }
467
468 alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
469 return overrun;
470}
471EXPORT_SYMBOL_GPL(alarm_forward);
472
473u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
474{
475 struct alarm_base *base = &alarm_bases[alarm->type];
476
477 return alarm_forward(alarm, base->get_ktime(), interval);
478}
479EXPORT_SYMBOL_GPL(alarm_forward_now);
480
481#ifdef CONFIG_POSIX_TIMERS
482
483static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
484{
485 struct alarm_base *base;
486 unsigned long flags;
487 ktime_t delta;
488
489 switch(type) {
490 case ALARM_REALTIME:
491 base = &alarm_bases[ALARM_REALTIME];
492 type = ALARM_REALTIME_FREEZER;
493 break;
494 case ALARM_BOOTTIME:
495 base = &alarm_bases[ALARM_BOOTTIME];
496 type = ALARM_BOOTTIME_FREEZER;
497 break;
498 default:
499 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
500 return;
501 }
502
503 delta = ktime_sub(absexp, base->get_ktime());
504
505 spin_lock_irqsave(&freezer_delta_lock, flags);
506 if (!freezer_delta || (delta < freezer_delta)) {
507 freezer_delta = delta;
508 freezer_expires = absexp;
509 freezer_alarmtype = type;
510 }
511 spin_unlock_irqrestore(&freezer_delta_lock, flags);
512}
513
514/**
515 * clock2alarm - helper that converts from clockid to alarmtypes
516 * @clockid: clockid.
517 */
518static enum alarmtimer_type clock2alarm(clockid_t clockid)
519{
520 if (clockid == CLOCK_REALTIME_ALARM)
521 return ALARM_REALTIME;
522 if (clockid == CLOCK_BOOTTIME_ALARM)
523 return ALARM_BOOTTIME;
524 return -1;
525}
526
527/**
528 * alarm_handle_timer - Callback for posix timers
529 * @alarm: alarm that fired
530 * @now: time at the timer expiration
531 *
532 * Posix timer callback for expired alarm timers.
533 *
534 * Return: whether the timer is to be restarted
535 */
536static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
537 ktime_t now)
538{
539 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
540 it.alarm.alarmtimer);
541 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
542 unsigned long flags;
543 int si_private = 0;
544
545 spin_lock_irqsave(&ptr->it_lock, flags);
546
547 ptr->it_active = 0;
548 if (ptr->it_interval)
549 si_private = ++ptr->it_requeue_pending;
550
551 if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
552 /*
553 * Handle ignored signals and rearm the timer. This will go
554 * away once we handle ignored signals proper.
555 */
556 ptr->it_overrun += alarm_forward_now(alarm, ptr->it_interval);
557 ++ptr->it_requeue_pending;
558 ptr->it_active = 1;
559 result = ALARMTIMER_RESTART;
560 }
561 spin_unlock_irqrestore(&ptr->it_lock, flags);
562
563 return result;
564}
565
566/**
567 * alarm_timer_rearm - Posix timer callback for rearming timer
568 * @timr: Pointer to the posixtimer data struct
569 */
570static void alarm_timer_rearm(struct k_itimer *timr)
571{
572 struct alarm *alarm = &timr->it.alarm.alarmtimer;
573
574 timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
575 alarm_start(alarm, alarm->node.expires);
576}
577
578/**
579 * alarm_timer_forward - Posix timer callback for forwarding timer
580 * @timr: Pointer to the posixtimer data struct
581 * @now: Current time to forward the timer against
582 */
583static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
584{
585 struct alarm *alarm = &timr->it.alarm.alarmtimer;
586
587 return alarm_forward(alarm, timr->it_interval, now);
588}
589
590/**
591 * alarm_timer_remaining - Posix timer callback to retrieve remaining time
592 * @timr: Pointer to the posixtimer data struct
593 * @now: Current time to calculate against
594 */
595static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
596{
597 struct alarm *alarm = &timr->it.alarm.alarmtimer;
598
599 return ktime_sub(alarm->node.expires, now);
600}
601
602/**
603 * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
604 * @timr: Pointer to the posixtimer data struct
605 */
606static int alarm_timer_try_to_cancel(struct k_itimer *timr)
607{
608 return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
609}
610
611/**
612 * alarm_timer_wait_running - Posix timer callback to wait for a timer
613 * @timr: Pointer to the posixtimer data struct
614 *
615 * Called from the core code when timer cancel detected that the callback
616 * is running. @timr is unlocked and rcu read lock is held to prevent it
617 * from being freed.
618 */
619static void alarm_timer_wait_running(struct k_itimer *timr)
620{
621 hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
622}
623
624/**
625 * alarm_timer_arm - Posix timer callback to arm a timer
626 * @timr: Pointer to the posixtimer data struct
627 * @expires: The new expiry time
628 * @absolute: Expiry value is absolute time
629 * @sigev_none: Posix timer does not deliver signals
630 */
631static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
632 bool absolute, bool sigev_none)
633{
634 struct alarm *alarm = &timr->it.alarm.alarmtimer;
635 struct alarm_base *base = &alarm_bases[alarm->type];
636
637 if (!absolute)
638 expires = ktime_add_safe(expires, base->get_ktime());
639 if (sigev_none)
640 alarm->node.expires = expires;
641 else
642 alarm_start(&timr->it.alarm.alarmtimer, expires);
643}
644
645/**
646 * alarm_clock_getres - posix getres interface
647 * @which_clock: clockid
648 * @tp: timespec to fill
649 *
650 * Returns the granularity of underlying alarm base clock
651 */
652static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
653{
654 if (!alarmtimer_get_rtcdev())
655 return -EINVAL;
656
657 tp->tv_sec = 0;
658 tp->tv_nsec = hrtimer_resolution;
659 return 0;
660}
661
662/**
663 * alarm_clock_get_timespec - posix clock_get_timespec interface
664 * @which_clock: clockid
665 * @tp: timespec to fill.
666 *
667 * Provides the underlying alarm base time in a tasks time namespace.
668 */
669static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)
670{
671 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
672
673 if (!alarmtimer_get_rtcdev())
674 return -EINVAL;
675
676 base->get_timespec(tp);
677
678 return 0;
679}
680
681/**
682 * alarm_clock_get_ktime - posix clock_get_ktime interface
683 * @which_clock: clockid
684 *
685 * Provides the underlying alarm base time in the root namespace.
686 */
687static ktime_t alarm_clock_get_ktime(clockid_t which_clock)
688{
689 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
690
691 if (!alarmtimer_get_rtcdev())
692 return -EINVAL;
693
694 return base->get_ktime();
695}
696
697/**
698 * alarm_timer_create - posix timer_create interface
699 * @new_timer: k_itimer pointer to manage
700 *
701 * Initializes the k_itimer structure.
702 */
703static int alarm_timer_create(struct k_itimer *new_timer)
704{
705 enum alarmtimer_type type;
706
707 if (!alarmtimer_get_rtcdev())
708 return -EOPNOTSUPP;
709
710 if (!capable(CAP_WAKE_ALARM))
711 return -EPERM;
712
713 type = clock2alarm(new_timer->it_clock);
714 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
715 return 0;
716}
717
718/**
719 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
720 * @alarm: ptr to alarm that fired
721 * @now: time at the timer expiration
722 *
723 * Wakes up the task that set the alarmtimer
724 *
725 * Return: ALARMTIMER_NORESTART
726 */
727static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
728 ktime_t now)
729{
730 struct task_struct *task = (struct task_struct *)alarm->data;
731
732 alarm->data = NULL;
733 if (task)
734 wake_up_process(task);
735 return ALARMTIMER_NORESTART;
736}
737
738/**
739 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
740 * @alarm: ptr to alarmtimer
741 * @absexp: absolute expiration time
742 * @type: alarm type (BOOTTIME/REALTIME).
743 *
744 * Sets the alarm timer and sleeps until it is fired or interrupted.
745 */
746static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
747 enum alarmtimer_type type)
748{
749 struct restart_block *restart;
750 alarm->data = (void *)current;
751 do {
752 set_current_state(TASK_INTERRUPTIBLE);
753 alarm_start(alarm, absexp);
754 if (likely(alarm->data))
755 schedule();
756
757 alarm_cancel(alarm);
758 } while (alarm->data && !signal_pending(current));
759
760 __set_current_state(TASK_RUNNING);
761
762 destroy_hrtimer_on_stack(&alarm->timer);
763
764 if (!alarm->data)
765 return 0;
766
767 if (freezing(current))
768 alarmtimer_freezerset(absexp, type);
769 restart = ¤t->restart_block;
770 if (restart->nanosleep.type != TT_NONE) {
771 struct timespec64 rmt;
772 ktime_t rem;
773
774 rem = ktime_sub(absexp, alarm_bases[type].get_ktime());
775
776 if (rem <= 0)
777 return 0;
778 rmt = ktime_to_timespec64(rem);
779
780 return nanosleep_copyout(restart, &rmt);
781 }
782 return -ERESTART_RESTARTBLOCK;
783}
784
785static void
786alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
787 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
788{
789 hrtimer_init_on_stack(&alarm->timer, alarm_bases[type].base_clockid,
790 HRTIMER_MODE_ABS);
791 __alarm_init(alarm, type, function);
792}
793
794/**
795 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
796 * @restart: ptr to restart block
797 *
798 * Handles restarted clock_nanosleep calls
799 */
800static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
801{
802 enum alarmtimer_type type = restart->nanosleep.clockid;
803 ktime_t exp = restart->nanosleep.expires;
804 struct alarm alarm;
805
806 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
807
808 return alarmtimer_do_nsleep(&alarm, exp, type);
809}
810
811/**
812 * alarm_timer_nsleep - alarmtimer nanosleep
813 * @which_clock: clockid
814 * @flags: determines abstime or relative
815 * @tsreq: requested sleep time (abs or rel)
816 *
817 * Handles clock_nanosleep calls against _ALARM clockids
818 */
819static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
820 const struct timespec64 *tsreq)
821{
822 enum alarmtimer_type type = clock2alarm(which_clock);
823 struct restart_block *restart = ¤t->restart_block;
824 struct alarm alarm;
825 ktime_t exp;
826 int ret = 0;
827
828 if (!alarmtimer_get_rtcdev())
829 return -EOPNOTSUPP;
830
831 if (flags & ~TIMER_ABSTIME)
832 return -EINVAL;
833
834 if (!capable(CAP_WAKE_ALARM))
835 return -EPERM;
836
837 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
838
839 exp = timespec64_to_ktime(*tsreq);
840 /* Convert (if necessary) to absolute time */
841 if (flags != TIMER_ABSTIME) {
842 ktime_t now = alarm_bases[type].get_ktime();
843
844 exp = ktime_add_safe(now, exp);
845 } else {
846 exp = timens_ktime_to_host(which_clock, exp);
847 }
848
849 ret = alarmtimer_do_nsleep(&alarm, exp, type);
850 if (ret != -ERESTART_RESTARTBLOCK)
851 return ret;
852
853 /* abs timers don't set remaining time or restart */
854 if (flags == TIMER_ABSTIME)
855 return -ERESTARTNOHAND;
856
857 restart->nanosleep.clockid = type;
858 restart->nanosleep.expires = exp;
859 set_restart_fn(restart, alarm_timer_nsleep_restart);
860 return ret;
861}
862
863const struct k_clock alarm_clock = {
864 .clock_getres = alarm_clock_getres,
865 .clock_get_ktime = alarm_clock_get_ktime,
866 .clock_get_timespec = alarm_clock_get_timespec,
867 .timer_create = alarm_timer_create,
868 .timer_set = common_timer_set,
869 .timer_del = common_timer_del,
870 .timer_get = common_timer_get,
871 .timer_arm = alarm_timer_arm,
872 .timer_rearm = alarm_timer_rearm,
873 .timer_forward = alarm_timer_forward,
874 .timer_remaining = alarm_timer_remaining,
875 .timer_try_to_cancel = alarm_timer_try_to_cancel,
876 .timer_wait_running = alarm_timer_wait_running,
877 .nsleep = alarm_timer_nsleep,
878};
879#endif /* CONFIG_POSIX_TIMERS */
880
881
882/* Suspend hook structures */
883static const struct dev_pm_ops alarmtimer_pm_ops = {
884 .suspend = alarmtimer_suspend,
885 .resume = alarmtimer_resume,
886};
887
888static struct platform_driver alarmtimer_driver = {
889 .driver = {
890 .name = "alarmtimer",
891 .pm = &alarmtimer_pm_ops,
892 }
893};
894
895static void get_boottime_timespec(struct timespec64 *tp)
896{
897 ktime_get_boottime_ts64(tp);
898 timens_add_boottime(tp);
899}
900
901/**
902 * alarmtimer_init - Initialize alarm timer code
903 *
904 * This function initializes the alarm bases and registers
905 * the posix clock ids.
906 */
907static int __init alarmtimer_init(void)
908{
909 int error;
910 int i;
911
912 alarmtimer_rtc_timer_init();
913
914 /* Initialize alarm bases */
915 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
916 alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
917 alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64;
918 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
919 alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
920 alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec;
921 for (i = 0; i < ALARM_NUMTYPE; i++) {
922 timerqueue_init_head(&alarm_bases[i].timerqueue);
923 spin_lock_init(&alarm_bases[i].lock);
924 }
925
926 error = alarmtimer_rtc_interface_setup();
927 if (error)
928 return error;
929
930 error = platform_driver_register(&alarmtimer_driver);
931 if (error)
932 goto out_if;
933
934 return 0;
935out_if:
936 alarmtimer_rtc_interface_remove();
937 return error;
938}
939device_initcall(alarmtimer_init);