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