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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 ktime_t (*gettime)(void);
41 clockid_t base_clockid;
42} alarm_bases[ALARM_NUMTYPE];
43
44/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
45static ktime_t freezer_delta;
46static DEFINE_SPINLOCK(freezer_delta_lock);
47
48static struct wakeup_source *ws;
49
50#ifdef CONFIG_RTC_CLASS
51/* rtc timer and device for setting alarm wakeups at suspend */
52static struct rtc_timer rtctimer;
53static struct rtc_device *rtcdev;
54static DEFINE_SPINLOCK(rtcdev_lock);
55
56/**
57 * alarmtimer_get_rtcdev - Return selected rtcdevice
58 *
59 * This function returns the rtc device to use for wakealarms.
60 * If one has not already been chosen, it checks to see if a
61 * functional rtc device is available.
62 */
63struct rtc_device *alarmtimer_get_rtcdev(void)
64{
65 unsigned long flags;
66 struct rtc_device *ret;
67
68 spin_lock_irqsave(&rtcdev_lock, flags);
69 ret = rtcdev;
70 spin_unlock_irqrestore(&rtcdev_lock, flags);
71
72 return ret;
73}
74EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
75
76static int alarmtimer_rtc_add_device(struct device *dev,
77 struct class_interface *class_intf)
78{
79 unsigned long flags;
80 struct rtc_device *rtc = to_rtc_device(dev);
81
82 if (rtcdev)
83 return -EBUSY;
84
85 if (!rtc->ops->set_alarm)
86 return -1;
87 if (!device_may_wakeup(rtc->dev.parent))
88 return -1;
89
90 spin_lock_irqsave(&rtcdev_lock, flags);
91 if (!rtcdev) {
92 rtcdev = rtc;
93 /* hold a reference so it doesn't go away */
94 get_device(dev);
95 }
96 spin_unlock_irqrestore(&rtcdev_lock, flags);
97 return 0;
98}
99
100static inline void alarmtimer_rtc_timer_init(void)
101{
102 rtc_timer_init(&rtctimer, NULL, NULL);
103}
104
105static struct class_interface alarmtimer_rtc_interface = {
106 .add_dev = &alarmtimer_rtc_add_device,
107};
108
109static int alarmtimer_rtc_interface_setup(void)
110{
111 alarmtimer_rtc_interface.class = rtc_class;
112 return class_interface_register(&alarmtimer_rtc_interface);
113}
114static void alarmtimer_rtc_interface_remove(void)
115{
116 class_interface_unregister(&alarmtimer_rtc_interface);
117}
118#else
119struct rtc_device *alarmtimer_get_rtcdev(void)
120{
121 return NULL;
122}
123#define rtcdev (NULL)
124static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
125static inline void alarmtimer_rtc_interface_remove(void) { }
126static inline void alarmtimer_rtc_timer_init(void) { }
127#endif
128
129/**
130 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
131 * @base: pointer to the base where the timer is being run
132 * @alarm: pointer to alarm being enqueued.
133 *
134 * Adds alarm to a alarm_base timerqueue
135 *
136 * Must hold base->lock when calling.
137 */
138static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
139{
140 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
141 timerqueue_del(&base->timerqueue, &alarm->node);
142
143 timerqueue_add(&base->timerqueue, &alarm->node);
144 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
145}
146
147/**
148 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
149 * @base: pointer to the base where the timer is running
150 * @alarm: pointer to alarm being removed
151 *
152 * Removes alarm to a alarm_base timerqueue
153 *
154 * Must hold base->lock when calling.
155 */
156static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
157{
158 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
159 return;
160
161 timerqueue_del(&base->timerqueue, &alarm->node);
162 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
163}
164
165
166/**
167 * alarmtimer_fired - Handles alarm hrtimer being fired.
168 * @timer: pointer to hrtimer being run
169 *
170 * When a alarm timer fires, this runs through the timerqueue to
171 * see which alarms expired, and runs those. If there are more alarm
172 * timers queued for the future, we set the hrtimer to fire when
173 * when the next future alarm timer expires.
174 */
175static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
176{
177 struct alarm *alarm = container_of(timer, struct alarm, timer);
178 struct alarm_base *base = &alarm_bases[alarm->type];
179 unsigned long flags;
180 int ret = HRTIMER_NORESTART;
181 int restart = ALARMTIMER_NORESTART;
182
183 spin_lock_irqsave(&base->lock, flags);
184 alarmtimer_dequeue(base, alarm);
185 spin_unlock_irqrestore(&base->lock, flags);
186
187 if (alarm->function)
188 restart = alarm->function(alarm, base->gettime());
189
190 spin_lock_irqsave(&base->lock, flags);
191 if (restart != ALARMTIMER_NORESTART) {
192 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
193 alarmtimer_enqueue(base, alarm);
194 ret = HRTIMER_RESTART;
195 }
196 spin_unlock_irqrestore(&base->lock, flags);
197
198 return ret;
199
200}
201
202ktime_t alarm_expires_remaining(const struct alarm *alarm)
203{
204 struct alarm_base *base = &alarm_bases[alarm->type];
205 return ktime_sub(alarm->node.expires, base->gettime());
206}
207EXPORT_SYMBOL_GPL(alarm_expires_remaining);
208
209#ifdef CONFIG_RTC_CLASS
210/**
211 * alarmtimer_suspend - Suspend time callback
212 * @dev: unused
213 * @state: unused
214 *
215 * When we are going into suspend, we look through the bases
216 * to see which is the soonest timer to expire. We then
217 * set an rtc timer to fire that far into the future, which
218 * will wake us from suspend.
219 */
220static int alarmtimer_suspend(struct device *dev)
221{
222 struct rtc_time tm;
223 ktime_t min, now;
224 unsigned long flags;
225 struct rtc_device *rtc;
226 int i;
227 int ret;
228
229 spin_lock_irqsave(&freezer_delta_lock, flags);
230 min = freezer_delta;
231 freezer_delta = ktime_set(0, 0);
232 spin_unlock_irqrestore(&freezer_delta_lock, flags);
233
234 rtc = alarmtimer_get_rtcdev();
235 /* If we have no rtcdev, just return */
236 if (!rtc)
237 return 0;
238
239 /* Find the soonest timer to expire*/
240 for (i = 0; i < ALARM_NUMTYPE; i++) {
241 struct alarm_base *base = &alarm_bases[i];
242 struct timerqueue_node *next;
243 ktime_t delta;
244
245 spin_lock_irqsave(&base->lock, flags);
246 next = timerqueue_getnext(&base->timerqueue);
247 spin_unlock_irqrestore(&base->lock, flags);
248 if (!next)
249 continue;
250 delta = ktime_sub(next->expires, base->gettime());
251 if (!min.tv64 || (delta.tv64 < min.tv64))
252 min = delta;
253 }
254 if (min.tv64 == 0)
255 return 0;
256
257 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
258 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
259 return -EBUSY;
260 }
261
262 /* Setup an rtc timer to fire that far in the future */
263 rtc_timer_cancel(rtc, &rtctimer);
264 rtc_read_time(rtc, &tm);
265 now = rtc_tm_to_ktime(tm);
266 now = ktime_add(now, min);
267
268 /* Set alarm, if in the past reject suspend briefly to handle */
269 ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
270 if (ret < 0)
271 __pm_wakeup_event(ws, MSEC_PER_SEC);
272 return ret;
273}
274
275static int alarmtimer_resume(struct device *dev)
276{
277 struct rtc_device *rtc;
278
279 rtc = alarmtimer_get_rtcdev();
280 if (rtc)
281 rtc_timer_cancel(rtc, &rtctimer);
282 return 0;
283}
284
285#else
286static int alarmtimer_suspend(struct device *dev)
287{
288 return 0;
289}
290
291static int alarmtimer_resume(struct device *dev)
292{
293 return 0;
294}
295#endif
296
297static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
298{
299 ktime_t delta;
300 unsigned long flags;
301 struct alarm_base *base = &alarm_bases[type];
302
303 delta = ktime_sub(absexp, base->gettime());
304
305 spin_lock_irqsave(&freezer_delta_lock, flags);
306 if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
307 freezer_delta = delta;
308 spin_unlock_irqrestore(&freezer_delta_lock, flags);
309}
310
311
312/**
313 * alarm_init - Initialize an alarm structure
314 * @alarm: ptr to alarm to be initialized
315 * @type: the type of the alarm
316 * @function: callback that is run when the alarm fires
317 */
318void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
319 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
320{
321 timerqueue_init(&alarm->node);
322 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
323 HRTIMER_MODE_ABS);
324 alarm->timer.function = alarmtimer_fired;
325 alarm->function = function;
326 alarm->type = type;
327 alarm->state = ALARMTIMER_STATE_INACTIVE;
328}
329EXPORT_SYMBOL_GPL(alarm_init);
330
331/**
332 * alarm_start - Sets an absolute alarm to fire
333 * @alarm: ptr to alarm to set
334 * @start: time to run the alarm
335 */
336void alarm_start(struct alarm *alarm, ktime_t start)
337{
338 struct alarm_base *base = &alarm_bases[alarm->type];
339 unsigned long flags;
340
341 spin_lock_irqsave(&base->lock, flags);
342 alarm->node.expires = start;
343 alarmtimer_enqueue(base, alarm);
344 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
345 spin_unlock_irqrestore(&base->lock, flags);
346}
347EXPORT_SYMBOL_GPL(alarm_start);
348
349/**
350 * alarm_start_relative - Sets a relative alarm to fire
351 * @alarm: ptr to alarm to set
352 * @start: time relative to now to run the alarm
353 */
354void alarm_start_relative(struct alarm *alarm, ktime_t start)
355{
356 struct alarm_base *base = &alarm_bases[alarm->type];
357
358 start = ktime_add(start, base->gettime());
359 alarm_start(alarm, start);
360}
361EXPORT_SYMBOL_GPL(alarm_start_relative);
362
363void alarm_restart(struct alarm *alarm)
364{
365 struct alarm_base *base = &alarm_bases[alarm->type];
366 unsigned long flags;
367
368 spin_lock_irqsave(&base->lock, flags);
369 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
370 hrtimer_restart(&alarm->timer);
371 alarmtimer_enqueue(base, alarm);
372 spin_unlock_irqrestore(&base->lock, flags);
373}
374EXPORT_SYMBOL_GPL(alarm_restart);
375
376/**
377 * alarm_try_to_cancel - Tries to cancel an alarm timer
378 * @alarm: ptr to alarm to be canceled
379 *
380 * Returns 1 if the timer was canceled, 0 if it was not running,
381 * and -1 if the callback was running
382 */
383int alarm_try_to_cancel(struct alarm *alarm)
384{
385 struct alarm_base *base = &alarm_bases[alarm->type];
386 unsigned long flags;
387 int ret;
388
389 spin_lock_irqsave(&base->lock, flags);
390 ret = hrtimer_try_to_cancel(&alarm->timer);
391 if (ret >= 0)
392 alarmtimer_dequeue(base, alarm);
393 spin_unlock_irqrestore(&base->lock, flags);
394 return ret;
395}
396EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
397
398
399/**
400 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
401 * @alarm: ptr to alarm to be canceled
402 *
403 * Returns 1 if the timer was canceled, 0 if it was not active.
404 */
405int alarm_cancel(struct alarm *alarm)
406{
407 for (;;) {
408 int ret = alarm_try_to_cancel(alarm);
409 if (ret >= 0)
410 return ret;
411 cpu_relax();
412 }
413}
414EXPORT_SYMBOL_GPL(alarm_cancel);
415
416
417u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
418{
419 u64 overrun = 1;
420 ktime_t delta;
421
422 delta = ktime_sub(now, alarm->node.expires);
423
424 if (delta.tv64 < 0)
425 return 0;
426
427 if (unlikely(delta.tv64 >= interval.tv64)) {
428 s64 incr = ktime_to_ns(interval);
429
430 overrun = ktime_divns(delta, incr);
431
432 alarm->node.expires = ktime_add_ns(alarm->node.expires,
433 incr*overrun);
434
435 if (alarm->node.expires.tv64 > now.tv64)
436 return overrun;
437 /*
438 * This (and the ktime_add() below) is the
439 * correction for exact:
440 */
441 overrun++;
442 }
443
444 alarm->node.expires = ktime_add(alarm->node.expires, interval);
445 return overrun;
446}
447EXPORT_SYMBOL_GPL(alarm_forward);
448
449u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
450{
451 struct alarm_base *base = &alarm_bases[alarm->type];
452
453 return alarm_forward(alarm, base->gettime(), interval);
454}
455EXPORT_SYMBOL_GPL(alarm_forward_now);
456
457
458/**
459 * clock2alarm - helper that converts from clockid to alarmtypes
460 * @clockid: clockid.
461 */
462static enum alarmtimer_type clock2alarm(clockid_t clockid)
463{
464 if (clockid == CLOCK_REALTIME_ALARM)
465 return ALARM_REALTIME;
466 if (clockid == CLOCK_BOOTTIME_ALARM)
467 return ALARM_BOOTTIME;
468 return -1;
469}
470
471/**
472 * alarm_handle_timer - Callback for posix timers
473 * @alarm: alarm that fired
474 *
475 * Posix timer callback for expired alarm timers.
476 */
477static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
478 ktime_t now)
479{
480 unsigned long flags;
481 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
482 it.alarm.alarmtimer);
483 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
484
485 spin_lock_irqsave(&ptr->it_lock, flags);
486 if ((ptr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) {
487 if (posix_timer_event(ptr, 0) != 0)
488 ptr->it_overrun++;
489 }
490
491 /* Re-add periodic timers */
492 if (ptr->it.alarm.interval.tv64) {
493 ptr->it_overrun += alarm_forward(alarm, now,
494 ptr->it.alarm.interval);
495 result = ALARMTIMER_RESTART;
496 }
497 spin_unlock_irqrestore(&ptr->it_lock, flags);
498
499 return result;
500}
501
502/**
503 * alarm_clock_getres - posix getres interface
504 * @which_clock: clockid
505 * @tp: timespec to fill
506 *
507 * Returns the granularity of underlying alarm base clock
508 */
509static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
510{
511 if (!alarmtimer_get_rtcdev())
512 return -EINVAL;
513
514 tp->tv_sec = 0;
515 tp->tv_nsec = hrtimer_resolution;
516 return 0;
517}
518
519/**
520 * alarm_clock_get - posix clock_get interface
521 * @which_clock: clockid
522 * @tp: timespec to fill.
523 *
524 * Provides the underlying alarm base time.
525 */
526static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
527{
528 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
529
530 if (!alarmtimer_get_rtcdev())
531 return -EINVAL;
532
533 *tp = ktime_to_timespec(base->gettime());
534 return 0;
535}
536
537/**
538 * alarm_timer_create - posix timer_create interface
539 * @new_timer: k_itimer pointer to manage
540 *
541 * Initializes the k_itimer structure.
542 */
543static int alarm_timer_create(struct k_itimer *new_timer)
544{
545 enum alarmtimer_type type;
546 struct alarm_base *base;
547
548 if (!alarmtimer_get_rtcdev())
549 return -ENOTSUPP;
550
551 if (!capable(CAP_WAKE_ALARM))
552 return -EPERM;
553
554 type = clock2alarm(new_timer->it_clock);
555 base = &alarm_bases[type];
556 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
557 return 0;
558}
559
560/**
561 * alarm_timer_get - posix timer_get interface
562 * @new_timer: k_itimer pointer
563 * @cur_setting: itimerspec data to fill
564 *
565 * Copies out the current itimerspec data
566 */
567static void alarm_timer_get(struct k_itimer *timr,
568 struct itimerspec *cur_setting)
569{
570 ktime_t relative_expiry_time =
571 alarm_expires_remaining(&(timr->it.alarm.alarmtimer));
572
573 if (ktime_to_ns(relative_expiry_time) > 0) {
574 cur_setting->it_value = ktime_to_timespec(relative_expiry_time);
575 } else {
576 cur_setting->it_value.tv_sec = 0;
577 cur_setting->it_value.tv_nsec = 0;
578 }
579
580 cur_setting->it_interval = ktime_to_timespec(timr->it.alarm.interval);
581}
582
583/**
584 * alarm_timer_del - posix timer_del interface
585 * @timr: k_itimer pointer to be deleted
586 *
587 * Cancels any programmed alarms for the given timer.
588 */
589static int alarm_timer_del(struct k_itimer *timr)
590{
591 if (!rtcdev)
592 return -ENOTSUPP;
593
594 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
595 return TIMER_RETRY;
596
597 return 0;
598}
599
600/**
601 * alarm_timer_set - posix timer_set interface
602 * @timr: k_itimer pointer to be deleted
603 * @flags: timer flags
604 * @new_setting: itimerspec to be used
605 * @old_setting: itimerspec being replaced
606 *
607 * Sets the timer to new_setting, and starts the timer.
608 */
609static int alarm_timer_set(struct k_itimer *timr, int flags,
610 struct itimerspec *new_setting,
611 struct itimerspec *old_setting)
612{
613 ktime_t exp;
614
615 if (!rtcdev)
616 return -ENOTSUPP;
617
618 if (flags & ~TIMER_ABSTIME)
619 return -EINVAL;
620
621 if (old_setting)
622 alarm_timer_get(timr, old_setting);
623
624 /* If the timer was already set, cancel it */
625 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
626 return TIMER_RETRY;
627
628 /* start the timer */
629 timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
630 exp = timespec_to_ktime(new_setting->it_value);
631 /* Convert (if necessary) to absolute time */
632 if (flags != TIMER_ABSTIME) {
633 ktime_t now;
634
635 now = alarm_bases[timr->it.alarm.alarmtimer.type].gettime();
636 exp = ktime_add(now, exp);
637 }
638
639 alarm_start(&timr->it.alarm.alarmtimer, exp);
640 return 0;
641}
642
643/**
644 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
645 * @alarm: ptr to alarm that fired
646 *
647 * Wakes up the task that set the alarmtimer
648 */
649static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
650 ktime_t now)
651{
652 struct task_struct *task = (struct task_struct *)alarm->data;
653
654 alarm->data = NULL;
655 if (task)
656 wake_up_process(task);
657 return ALARMTIMER_NORESTART;
658}
659
660/**
661 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
662 * @alarm: ptr to alarmtimer
663 * @absexp: absolute expiration time
664 *
665 * Sets the alarm timer and sleeps until it is fired or interrupted.
666 */
667static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
668{
669 alarm->data = (void *)current;
670 do {
671 set_current_state(TASK_INTERRUPTIBLE);
672 alarm_start(alarm, absexp);
673 if (likely(alarm->data))
674 schedule();
675
676 alarm_cancel(alarm);
677 } while (alarm->data && !signal_pending(current));
678
679 __set_current_state(TASK_RUNNING);
680
681 return (alarm->data == NULL);
682}
683
684
685/**
686 * update_rmtp - Update remaining timespec value
687 * @exp: expiration time
688 * @type: timer type
689 * @rmtp: user pointer to remaining timepsec value
690 *
691 * Helper function that fills in rmtp value with time between
692 * now and the exp value
693 */
694static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
695 struct timespec __user *rmtp)
696{
697 struct timespec rmt;
698 ktime_t rem;
699
700 rem = ktime_sub(exp, alarm_bases[type].gettime());
701
702 if (rem.tv64 <= 0)
703 return 0;
704 rmt = ktime_to_timespec(rem);
705
706 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
707 return -EFAULT;
708
709 return 1;
710
711}
712
713/**
714 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
715 * @restart: ptr to restart block
716 *
717 * Handles restarted clock_nanosleep calls
718 */
719static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
720{
721 enum alarmtimer_type type = restart->nanosleep.clockid;
722 ktime_t exp;
723 struct timespec __user *rmtp;
724 struct alarm alarm;
725 int ret = 0;
726
727 exp.tv64 = restart->nanosleep.expires;
728 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
729
730 if (alarmtimer_do_nsleep(&alarm, exp))
731 goto out;
732
733 if (freezing(current))
734 alarmtimer_freezerset(exp, type);
735
736 rmtp = restart->nanosleep.rmtp;
737 if (rmtp) {
738 ret = update_rmtp(exp, type, rmtp);
739 if (ret <= 0)
740 goto out;
741 }
742
743
744 /* The other values in restart are already filled in */
745 ret = -ERESTART_RESTARTBLOCK;
746out:
747 return ret;
748}
749
750/**
751 * alarm_timer_nsleep - alarmtimer nanosleep
752 * @which_clock: clockid
753 * @flags: determins abstime or relative
754 * @tsreq: requested sleep time (abs or rel)
755 * @rmtp: remaining sleep time saved
756 *
757 * Handles clock_nanosleep calls against _ALARM clockids
758 */
759static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
760 struct timespec *tsreq, struct timespec __user *rmtp)
761{
762 enum alarmtimer_type type = clock2alarm(which_clock);
763 struct alarm alarm;
764 ktime_t exp;
765 int ret = 0;
766 struct restart_block *restart;
767
768 if (!alarmtimer_get_rtcdev())
769 return -ENOTSUPP;
770
771 if (flags & ~TIMER_ABSTIME)
772 return -EINVAL;
773
774 if (!capable(CAP_WAKE_ALARM))
775 return -EPERM;
776
777 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
778
779 exp = timespec_to_ktime(*tsreq);
780 /* Convert (if necessary) to absolute time */
781 if (flags != TIMER_ABSTIME) {
782 ktime_t now = alarm_bases[type].gettime();
783 exp = ktime_add(now, exp);
784 }
785
786 if (alarmtimer_do_nsleep(&alarm, exp))
787 goto out;
788
789 if (freezing(current))
790 alarmtimer_freezerset(exp, type);
791
792 /* abs timers don't set remaining time or restart */
793 if (flags == TIMER_ABSTIME) {
794 ret = -ERESTARTNOHAND;
795 goto out;
796 }
797
798 if (rmtp) {
799 ret = update_rmtp(exp, type, rmtp);
800 if (ret <= 0)
801 goto out;
802 }
803
804 restart = ¤t->restart_block;
805 restart->fn = alarm_timer_nsleep_restart;
806 restart->nanosleep.clockid = type;
807 restart->nanosleep.expires = exp.tv64;
808 restart->nanosleep.rmtp = rmtp;
809 ret = -ERESTART_RESTARTBLOCK;
810
811out:
812 return ret;
813}
814
815
816/* Suspend hook structures */
817static const struct dev_pm_ops alarmtimer_pm_ops = {
818 .suspend = alarmtimer_suspend,
819 .resume = alarmtimer_resume,
820};
821
822static struct platform_driver alarmtimer_driver = {
823 .driver = {
824 .name = "alarmtimer",
825 .pm = &alarmtimer_pm_ops,
826 }
827};
828
829/**
830 * alarmtimer_init - Initialize alarm timer code
831 *
832 * This function initializes the alarm bases and registers
833 * the posix clock ids.
834 */
835static int __init alarmtimer_init(void)
836{
837 struct platform_device *pdev;
838 int error = 0;
839 int i;
840 struct k_clock alarm_clock = {
841 .clock_getres = alarm_clock_getres,
842 .clock_get = alarm_clock_get,
843 .timer_create = alarm_timer_create,
844 .timer_set = alarm_timer_set,
845 .timer_del = alarm_timer_del,
846 .timer_get = alarm_timer_get,
847 .nsleep = alarm_timer_nsleep,
848 };
849
850 alarmtimer_rtc_timer_init();
851
852 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
853 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
854
855 /* Initialize alarm bases */
856 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
857 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
858 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
859 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
860 for (i = 0; i < ALARM_NUMTYPE; i++) {
861 timerqueue_init_head(&alarm_bases[i].timerqueue);
862 spin_lock_init(&alarm_bases[i].lock);
863 }
864
865 error = alarmtimer_rtc_interface_setup();
866 if (error)
867 return error;
868
869 error = platform_driver_register(&alarmtimer_driver);
870 if (error)
871 goto out_if;
872
873 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
874 if (IS_ERR(pdev)) {
875 error = PTR_ERR(pdev);
876 goto out_drv;
877 }
878 ws = wakeup_source_register("alarmtimer");
879 return 0;
880
881out_drv:
882 platform_driver_unregister(&alarmtimer_driver);
883out_if:
884 alarmtimer_rtc_interface_remove();
885 return error;
886}
887device_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{
86 unsigned long flags;
87 struct rtc_device *rtc = to_rtc_device(dev);
88 struct platform_device *pdev;
89 int ret = 0;
90
91 if (rtcdev)
92 return -EBUSY;
93
94 if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
95 return -1;
96 if (!device_may_wakeup(rtc->dev.parent))
97 return -1;
98
99 pdev = platform_device_register_data(dev, "alarmtimer",
100 PLATFORM_DEVID_AUTO, NULL, 0);
101 if (!IS_ERR(pdev))
102 device_init_wakeup(&pdev->dev, true);
103
104 spin_lock_irqsave(&rtcdev_lock, flags);
105 if (!IS_ERR(pdev) && !rtcdev) {
106 if (!try_module_get(rtc->owner)) {
107 ret = -1;
108 goto unlock;
109 }
110
111 rtcdev = rtc;
112 /* hold a reference so it doesn't go away */
113 get_device(dev);
114 pdev = NULL;
115 } else {
116 ret = -1;
117 }
118unlock:
119 spin_unlock_irqrestore(&rtcdev_lock, flags);
120
121 platform_device_unregister(pdev);
122
123 return ret;
124}
125
126static inline void alarmtimer_rtc_timer_init(void)
127{
128 rtc_timer_init(&rtctimer, NULL, NULL);
129}
130
131static struct class_interface alarmtimer_rtc_interface = {
132 .add_dev = &alarmtimer_rtc_add_device,
133};
134
135static int alarmtimer_rtc_interface_setup(void)
136{
137 alarmtimer_rtc_interface.class = &rtc_class;
138 return class_interface_register(&alarmtimer_rtc_interface);
139}
140static void alarmtimer_rtc_interface_remove(void)
141{
142 class_interface_unregister(&alarmtimer_rtc_interface);
143}
144#else
145static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
146static inline void alarmtimer_rtc_interface_remove(void) { }
147static inline void alarmtimer_rtc_timer_init(void) { }
148#endif
149
150/**
151 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
152 * @base: pointer to the base where the timer is being run
153 * @alarm: pointer to alarm being enqueued.
154 *
155 * Adds alarm to a alarm_base timerqueue
156 *
157 * Must hold base->lock when calling.
158 */
159static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
160{
161 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
162 timerqueue_del(&base->timerqueue, &alarm->node);
163
164 timerqueue_add(&base->timerqueue, &alarm->node);
165 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
166}
167
168/**
169 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
170 * @base: pointer to the base where the timer is running
171 * @alarm: pointer to alarm being removed
172 *
173 * Removes alarm to a alarm_base timerqueue
174 *
175 * Must hold base->lock when calling.
176 */
177static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
178{
179 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
180 return;
181
182 timerqueue_del(&base->timerqueue, &alarm->node);
183 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
184}
185
186
187/**
188 * alarmtimer_fired - Handles alarm hrtimer being fired.
189 * @timer: pointer to hrtimer being run
190 *
191 * When a alarm timer fires, this runs through the timerqueue to
192 * see which alarms expired, and runs those. If there are more alarm
193 * timers queued for the future, we set the hrtimer to fire when
194 * the next future alarm timer expires.
195 */
196static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
197{
198 struct alarm *alarm = container_of(timer, struct alarm, timer);
199 struct alarm_base *base = &alarm_bases[alarm->type];
200
201 scoped_guard (spinlock_irqsave, &base->lock)
202 alarmtimer_dequeue(base, alarm);
203
204 if (alarm->function)
205 alarm->function(alarm, base->get_ktime());
206
207 trace_alarmtimer_fired(alarm, base->get_ktime());
208 return HRTIMER_NORESTART;
209}
210
211ktime_t alarm_expires_remaining(const struct alarm *alarm)
212{
213 struct alarm_base *base = &alarm_bases[alarm->type];
214 return ktime_sub(alarm->node.expires, base->get_ktime());
215}
216EXPORT_SYMBOL_GPL(alarm_expires_remaining);
217
218#ifdef CONFIG_RTC_CLASS
219/**
220 * alarmtimer_suspend - Suspend time callback
221 * @dev: unused
222 *
223 * When we are going into suspend, we look through the bases
224 * to see which is the soonest timer to expire. We then
225 * set an rtc timer to fire that far into the future, which
226 * will wake us from suspend.
227 */
228static int alarmtimer_suspend(struct device *dev)
229{
230 ktime_t min, now, expires;
231 int i, ret, type;
232 struct rtc_device *rtc;
233 unsigned long flags;
234 struct rtc_time tm;
235
236 spin_lock_irqsave(&freezer_delta_lock, flags);
237 min = freezer_delta;
238 expires = freezer_expires;
239 type = freezer_alarmtype;
240 freezer_delta = 0;
241 spin_unlock_irqrestore(&freezer_delta_lock, flags);
242
243 rtc = alarmtimer_get_rtcdev();
244 /* If we have no rtcdev, just return */
245 if (!rtc)
246 return 0;
247
248 /* Find the soonest timer to expire*/
249 for (i = 0; i < ALARM_NUMTYPE; i++) {
250 struct alarm_base *base = &alarm_bases[i];
251 struct timerqueue_node *next;
252 ktime_t delta;
253
254 spin_lock_irqsave(&base->lock, flags);
255 next = timerqueue_getnext(&base->timerqueue);
256 spin_unlock_irqrestore(&base->lock, flags);
257 if (!next)
258 continue;
259 delta = ktime_sub(next->expires, base->get_ktime());
260 if (!min || (delta < min)) {
261 expires = next->expires;
262 min = delta;
263 type = i;
264 }
265 }
266 if (min == 0)
267 return 0;
268
269 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
270 pm_wakeup_event(dev, 2 * MSEC_PER_SEC);
271 return -EBUSY;
272 }
273
274 trace_alarmtimer_suspend(expires, type);
275
276 /* Setup an rtc timer to fire that far in the future */
277 rtc_timer_cancel(rtc, &rtctimer);
278 rtc_read_time(rtc, &tm);
279 now = rtc_tm_to_ktime(tm);
280
281 /*
282 * If the RTC alarm timer only supports a limited time offset, set the
283 * alarm time to the maximum supported value.
284 * The system may wake up earlier (possibly much earlier) than expected
285 * when the alarmtimer runs. This is the best the kernel can do if
286 * the alarmtimer exceeds the time that the rtc device can be programmed
287 * for.
288 */
289 min = rtc_bound_alarmtime(rtc, min);
290
291 now = ktime_add(now, min);
292
293 /* Set alarm, if in the past reject suspend briefly to handle */
294 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
295 if (ret < 0)
296 pm_wakeup_event(dev, MSEC_PER_SEC);
297 return ret;
298}
299
300static int alarmtimer_resume(struct device *dev)
301{
302 struct rtc_device *rtc;
303
304 rtc = alarmtimer_get_rtcdev();
305 if (rtc)
306 rtc_timer_cancel(rtc, &rtctimer);
307 return 0;
308}
309
310#else
311static int alarmtimer_suspend(struct device *dev)
312{
313 return 0;
314}
315
316static int alarmtimer_resume(struct device *dev)
317{
318 return 0;
319}
320#endif
321
322static void
323__alarm_init(struct alarm *alarm, enum alarmtimer_type type,
324 void (*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_init - Initialize an alarm structure
334 * @alarm: ptr to alarm to be initialized
335 * @type: the type of the alarm
336 * @function: callback that is run when the alarm fires
337 */
338void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
339 void (*function)(struct alarm *, ktime_t))
340{
341 hrtimer_setup(&alarm->timer, alarmtimer_fired, alarm_bases[type].base_clockid,
342 HRTIMER_MODE_ABS);
343 __alarm_init(alarm, type, function);
344}
345EXPORT_SYMBOL_GPL(alarm_init);
346
347/**
348 * alarm_start - Sets an absolute alarm to fire
349 * @alarm: ptr to alarm to set
350 * @start: time to run the alarm
351 */
352void alarm_start(struct alarm *alarm, ktime_t start)
353{
354 struct alarm_base *base = &alarm_bases[alarm->type];
355 unsigned long flags;
356
357 spin_lock_irqsave(&base->lock, flags);
358 alarm->node.expires = start;
359 alarmtimer_enqueue(base, alarm);
360 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
361 spin_unlock_irqrestore(&base->lock, flags);
362
363 trace_alarmtimer_start(alarm, base->get_ktime());
364}
365EXPORT_SYMBOL_GPL(alarm_start);
366
367/**
368 * alarm_start_relative - Sets a relative alarm to fire
369 * @alarm: ptr to alarm to set
370 * @start: time relative to now to run the alarm
371 */
372void alarm_start_relative(struct alarm *alarm, ktime_t start)
373{
374 struct alarm_base *base = &alarm_bases[alarm->type];
375
376 start = ktime_add_safe(start, base->get_ktime());
377 alarm_start(alarm, start);
378}
379EXPORT_SYMBOL_GPL(alarm_start_relative);
380
381void alarm_restart(struct alarm *alarm)
382{
383 struct alarm_base *base = &alarm_bases[alarm->type];
384 unsigned long flags;
385
386 spin_lock_irqsave(&base->lock, flags);
387 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
388 hrtimer_restart(&alarm->timer);
389 alarmtimer_enqueue(base, alarm);
390 spin_unlock_irqrestore(&base->lock, flags);
391}
392EXPORT_SYMBOL_GPL(alarm_restart);
393
394/**
395 * alarm_try_to_cancel - Tries to cancel an alarm timer
396 * @alarm: ptr to alarm to be canceled
397 *
398 * Returns 1 if the timer was canceled, 0 if it was not running,
399 * and -1 if the callback was running
400 */
401int alarm_try_to_cancel(struct alarm *alarm)
402{
403 struct alarm_base *base = &alarm_bases[alarm->type];
404 unsigned long flags;
405 int ret;
406
407 spin_lock_irqsave(&base->lock, flags);
408 ret = hrtimer_try_to_cancel(&alarm->timer);
409 if (ret >= 0)
410 alarmtimer_dequeue(base, alarm);
411 spin_unlock_irqrestore(&base->lock, flags);
412
413 trace_alarmtimer_cancel(alarm, base->get_ktime());
414 return ret;
415}
416EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
417
418
419/**
420 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
421 * @alarm: ptr to alarm to be canceled
422 *
423 * Returns 1 if the timer was canceled, 0 if it was not active.
424 */
425int alarm_cancel(struct alarm *alarm)
426{
427 for (;;) {
428 int ret = alarm_try_to_cancel(alarm);
429 if (ret >= 0)
430 return ret;
431 hrtimer_cancel_wait_running(&alarm->timer);
432 }
433}
434EXPORT_SYMBOL_GPL(alarm_cancel);
435
436
437u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
438{
439 u64 overrun = 1;
440 ktime_t delta;
441
442 delta = ktime_sub(now, alarm->node.expires);
443
444 if (delta < 0)
445 return 0;
446
447 if (unlikely(delta >= interval)) {
448 s64 incr = ktime_to_ns(interval);
449
450 overrun = ktime_divns(delta, incr);
451
452 alarm->node.expires = ktime_add_ns(alarm->node.expires,
453 incr*overrun);
454
455 if (alarm->node.expires > now)
456 return overrun;
457 /*
458 * This (and the ktime_add() below) is the
459 * correction for exact:
460 */
461 overrun++;
462 }
463
464 alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
465 return overrun;
466}
467EXPORT_SYMBOL_GPL(alarm_forward);
468
469u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
470{
471 struct alarm_base *base = &alarm_bases[alarm->type];
472
473 return alarm_forward(alarm, base->get_ktime(), interval);
474}
475EXPORT_SYMBOL_GPL(alarm_forward_now);
476
477#ifdef CONFIG_POSIX_TIMERS
478
479static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
480{
481 struct alarm_base *base;
482 unsigned long flags;
483 ktime_t delta;
484
485 switch(type) {
486 case ALARM_REALTIME:
487 base = &alarm_bases[ALARM_REALTIME];
488 type = ALARM_REALTIME_FREEZER;
489 break;
490 case ALARM_BOOTTIME:
491 base = &alarm_bases[ALARM_BOOTTIME];
492 type = ALARM_BOOTTIME_FREEZER;
493 break;
494 default:
495 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
496 return;
497 }
498
499 delta = ktime_sub(absexp, base->get_ktime());
500
501 spin_lock_irqsave(&freezer_delta_lock, flags);
502 if (!freezer_delta || (delta < freezer_delta)) {
503 freezer_delta = delta;
504 freezer_expires = absexp;
505 freezer_alarmtype = type;
506 }
507 spin_unlock_irqrestore(&freezer_delta_lock, flags);
508}
509
510/**
511 * clock2alarm - helper that converts from clockid to alarmtypes
512 * @clockid: clockid.
513 */
514static enum alarmtimer_type clock2alarm(clockid_t clockid)
515{
516 if (clockid == CLOCK_REALTIME_ALARM)
517 return ALARM_REALTIME;
518 if (clockid == CLOCK_BOOTTIME_ALARM)
519 return ALARM_BOOTTIME;
520 return -1;
521}
522
523/**
524 * alarm_handle_timer - Callback for posix timers
525 * @alarm: alarm that fired
526 * @now: time at the timer expiration
527 *
528 * Posix timer callback for expired alarm timers.
529 *
530 * Return: whether the timer is to be restarted
531 */
532static void alarm_handle_timer(struct alarm *alarm, ktime_t now)
533{
534 struct k_itimer *ptr = container_of(alarm, struct k_itimer, it.alarm.alarmtimer);
535
536 guard(spinlock_irqsave)(&ptr->it_lock);
537 posix_timer_queue_signal(ptr);
538}
539
540/**
541 * alarm_timer_rearm - Posix timer callback for rearming timer
542 * @timr: Pointer to the posixtimer data struct
543 */
544static void alarm_timer_rearm(struct k_itimer *timr)
545{
546 struct alarm *alarm = &timr->it.alarm.alarmtimer;
547
548 timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
549 alarm_start(alarm, alarm->node.expires);
550}
551
552/**
553 * alarm_timer_forward - Posix timer callback for forwarding timer
554 * @timr: Pointer to the posixtimer data struct
555 * @now: Current time to forward the timer against
556 */
557static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
558{
559 struct alarm *alarm = &timr->it.alarm.alarmtimer;
560
561 return alarm_forward(alarm, timr->it_interval, now);
562}
563
564/**
565 * alarm_timer_remaining - Posix timer callback to retrieve remaining time
566 * @timr: Pointer to the posixtimer data struct
567 * @now: Current time to calculate against
568 */
569static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
570{
571 struct alarm *alarm = &timr->it.alarm.alarmtimer;
572
573 return ktime_sub(alarm->node.expires, now);
574}
575
576/**
577 * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
578 * @timr: Pointer to the posixtimer data struct
579 */
580static int alarm_timer_try_to_cancel(struct k_itimer *timr)
581{
582 return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
583}
584
585/**
586 * alarm_timer_wait_running - Posix timer callback to wait for a timer
587 * @timr: Pointer to the posixtimer data struct
588 *
589 * Called from the core code when timer cancel detected that the callback
590 * is running. @timr is unlocked and rcu read lock is held to prevent it
591 * from being freed.
592 */
593static void alarm_timer_wait_running(struct k_itimer *timr)
594{
595 hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
596}
597
598/**
599 * alarm_timer_arm - Posix timer callback to arm a timer
600 * @timr: Pointer to the posixtimer data struct
601 * @expires: The new expiry time
602 * @absolute: Expiry value is absolute time
603 * @sigev_none: Posix timer does not deliver signals
604 */
605static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
606 bool absolute, bool sigev_none)
607{
608 struct alarm *alarm = &timr->it.alarm.alarmtimer;
609 struct alarm_base *base = &alarm_bases[alarm->type];
610
611 if (!absolute)
612 expires = ktime_add_safe(expires, base->get_ktime());
613 if (sigev_none)
614 alarm->node.expires = expires;
615 else
616 alarm_start(&timr->it.alarm.alarmtimer, expires);
617}
618
619/**
620 * alarm_clock_getres - posix getres interface
621 * @which_clock: clockid
622 * @tp: timespec to fill
623 *
624 * Returns the granularity of underlying alarm base clock
625 */
626static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
627{
628 if (!alarmtimer_get_rtcdev())
629 return -EINVAL;
630
631 tp->tv_sec = 0;
632 tp->tv_nsec = hrtimer_resolution;
633 return 0;
634}
635
636/**
637 * alarm_clock_get_timespec - posix clock_get_timespec interface
638 * @which_clock: clockid
639 * @tp: timespec to fill.
640 *
641 * Provides the underlying alarm base time in a tasks time namespace.
642 */
643static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)
644{
645 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
646
647 if (!alarmtimer_get_rtcdev())
648 return -EINVAL;
649
650 base->get_timespec(tp);
651
652 return 0;
653}
654
655/**
656 * alarm_clock_get_ktime - posix clock_get_ktime interface
657 * @which_clock: clockid
658 *
659 * Provides the underlying alarm base time in the root namespace.
660 */
661static ktime_t alarm_clock_get_ktime(clockid_t which_clock)
662{
663 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
664
665 if (!alarmtimer_get_rtcdev())
666 return -EINVAL;
667
668 return base->get_ktime();
669}
670
671/**
672 * alarm_timer_create - posix timer_create interface
673 * @new_timer: k_itimer pointer to manage
674 *
675 * Initializes the k_itimer structure.
676 */
677static int alarm_timer_create(struct k_itimer *new_timer)
678{
679 enum alarmtimer_type type;
680
681 if (!alarmtimer_get_rtcdev())
682 return -EOPNOTSUPP;
683
684 if (!capable(CAP_WAKE_ALARM))
685 return -EPERM;
686
687 type = clock2alarm(new_timer->it_clock);
688 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
689 return 0;
690}
691
692/**
693 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
694 * @alarm: ptr to alarm that fired
695 * @now: time at the timer expiration
696 *
697 * Wakes up the task that set the alarmtimer
698 */
699static void alarmtimer_nsleep_wakeup(struct alarm *alarm, ktime_t now)
700{
701 struct task_struct *task = alarm->data;
702
703 alarm->data = NULL;
704 if (task)
705 wake_up_process(task);
706}
707
708/**
709 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
710 * @alarm: ptr to alarmtimer
711 * @absexp: absolute expiration time
712 * @type: alarm type (BOOTTIME/REALTIME).
713 *
714 * Sets the alarm timer and sleeps until it is fired or interrupted.
715 */
716static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
717 enum alarmtimer_type type)
718{
719 struct restart_block *restart;
720 alarm->data = (void *)current;
721 do {
722 set_current_state(TASK_INTERRUPTIBLE);
723 alarm_start(alarm, absexp);
724 if (likely(alarm->data))
725 schedule();
726
727 alarm_cancel(alarm);
728 } while (alarm->data && !signal_pending(current));
729
730 __set_current_state(TASK_RUNNING);
731
732 destroy_hrtimer_on_stack(&alarm->timer);
733
734 if (!alarm->data)
735 return 0;
736
737 if (freezing(current))
738 alarmtimer_freezerset(absexp, type);
739 restart = ¤t->restart_block;
740 if (restart->nanosleep.type != TT_NONE) {
741 struct timespec64 rmt;
742 ktime_t rem;
743
744 rem = ktime_sub(absexp, alarm_bases[type].get_ktime());
745
746 if (rem <= 0)
747 return 0;
748 rmt = ktime_to_timespec64(rem);
749
750 return nanosleep_copyout(restart, &rmt);
751 }
752 return -ERESTART_RESTARTBLOCK;
753}
754
755static void
756alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
757 void (*function)(struct alarm *, ktime_t))
758{
759 hrtimer_setup_on_stack(&alarm->timer, alarmtimer_fired, alarm_bases[type].base_clockid,
760 HRTIMER_MODE_ABS);
761 __alarm_init(alarm, type, function);
762}
763
764/**
765 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
766 * @restart: ptr to restart block
767 *
768 * Handles restarted clock_nanosleep calls
769 */
770static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
771{
772 enum alarmtimer_type type = restart->nanosleep.clockid;
773 ktime_t exp = restart->nanosleep.expires;
774 struct alarm alarm;
775
776 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
777
778 return alarmtimer_do_nsleep(&alarm, exp, type);
779}
780
781/**
782 * alarm_timer_nsleep - alarmtimer nanosleep
783 * @which_clock: clockid
784 * @flags: determines abstime or relative
785 * @tsreq: requested sleep time (abs or rel)
786 *
787 * Handles clock_nanosleep calls against _ALARM clockids
788 */
789static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
790 const struct timespec64 *tsreq)
791{
792 enum alarmtimer_type type = clock2alarm(which_clock);
793 struct restart_block *restart = ¤t->restart_block;
794 struct alarm alarm;
795 ktime_t exp;
796 int ret;
797
798 if (!alarmtimer_get_rtcdev())
799 return -EOPNOTSUPP;
800
801 if (flags & ~TIMER_ABSTIME)
802 return -EINVAL;
803
804 if (!capable(CAP_WAKE_ALARM))
805 return -EPERM;
806
807 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
808
809 exp = timespec64_to_ktime(*tsreq);
810 /* Convert (if necessary) to absolute time */
811 if (flags != TIMER_ABSTIME) {
812 ktime_t now = alarm_bases[type].get_ktime();
813
814 exp = ktime_add_safe(now, exp);
815 } else {
816 exp = timens_ktime_to_host(which_clock, exp);
817 }
818
819 ret = alarmtimer_do_nsleep(&alarm, exp, type);
820 if (ret != -ERESTART_RESTARTBLOCK)
821 return ret;
822
823 /* abs timers don't set remaining time or restart */
824 if (flags == TIMER_ABSTIME)
825 return -ERESTARTNOHAND;
826
827 restart->nanosleep.clockid = type;
828 restart->nanosleep.expires = exp;
829 set_restart_fn(restart, alarm_timer_nsleep_restart);
830 return ret;
831}
832
833const struct k_clock alarm_clock = {
834 .clock_getres = alarm_clock_getres,
835 .clock_get_ktime = alarm_clock_get_ktime,
836 .clock_get_timespec = alarm_clock_get_timespec,
837 .timer_create = alarm_timer_create,
838 .timer_set = common_timer_set,
839 .timer_del = common_timer_del,
840 .timer_get = common_timer_get,
841 .timer_arm = alarm_timer_arm,
842 .timer_rearm = alarm_timer_rearm,
843 .timer_forward = alarm_timer_forward,
844 .timer_remaining = alarm_timer_remaining,
845 .timer_try_to_cancel = alarm_timer_try_to_cancel,
846 .timer_wait_running = alarm_timer_wait_running,
847 .nsleep = alarm_timer_nsleep,
848};
849#endif /* CONFIG_POSIX_TIMERS */
850
851
852/* Suspend hook structures */
853static const struct dev_pm_ops alarmtimer_pm_ops = {
854 .suspend = alarmtimer_suspend,
855 .resume = alarmtimer_resume,
856};
857
858static struct platform_driver alarmtimer_driver = {
859 .driver = {
860 .name = "alarmtimer",
861 .pm = &alarmtimer_pm_ops,
862 }
863};
864
865static void get_boottime_timespec(struct timespec64 *tp)
866{
867 ktime_get_boottime_ts64(tp);
868 timens_add_boottime(tp);
869}
870
871/**
872 * alarmtimer_init - Initialize alarm timer code
873 *
874 * This function initializes the alarm bases and registers
875 * the posix clock ids.
876 */
877static int __init alarmtimer_init(void)
878{
879 int error;
880 int i;
881
882 alarmtimer_rtc_timer_init();
883
884 /* Initialize alarm bases */
885 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
886 alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
887 alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64;
888 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
889 alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
890 alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec;
891 for (i = 0; i < ALARM_NUMTYPE; i++) {
892 timerqueue_init_head(&alarm_bases[i].timerqueue);
893 spin_lock_init(&alarm_bases[i].lock);
894 }
895
896 error = alarmtimer_rtc_interface_setup();
897 if (error)
898 return error;
899
900 error = platform_driver_register(&alarmtimer_driver);
901 if (error)
902 goto out_if;
903
904 return 0;
905out_if:
906 alarmtimer_rtc_interface_remove();
907 return error;
908}
909device_initcall(alarmtimer_init);