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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Alarmtimer interface
4 *
5 * This interface provides a timer which is similarto 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 Corperation
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
30#include "posix-timers.h"
31
32#define CREATE_TRACE_POINTS
33#include <trace/events/alarmtimer.h>
34
35/**
36 * struct alarm_base - Alarm timer bases
37 * @lock: Lock for syncrhonized access to the base
38 * @timerqueue: Timerqueue head managing the list of events
39 * @gettime: Function to read the time correlating to the base
40 * @base_clockid: clockid for the base
41 */
42static struct alarm_base {
43 spinlock_t lock;
44 struct timerqueue_head timerqueue;
45 ktime_t (*gettime)(void);
46 clockid_t base_clockid;
47} alarm_bases[ALARM_NUMTYPE];
48
49#if defined(CONFIG_POSIX_TIMERS) || defined(CONFIG_RTC_CLASS)
50/* freezer information to handle clock_nanosleep triggered wakeups */
51static enum alarmtimer_type freezer_alarmtype;
52static ktime_t freezer_expires;
53static ktime_t freezer_delta;
54static DEFINE_SPINLOCK(freezer_delta_lock);
55#endif
56
57#ifdef CONFIG_RTC_CLASS
58static struct wakeup_source *ws;
59
60/* rtc timer and device for setting alarm wakeups at suspend */
61static struct rtc_timer rtctimer;
62static struct rtc_device *rtcdev;
63static DEFINE_SPINLOCK(rtcdev_lock);
64
65/**
66 * alarmtimer_get_rtcdev - Return selected rtcdevice
67 *
68 * This function returns the rtc device to use for wakealarms.
69 * If one has not already been chosen, it checks to see if a
70 * functional rtc device is available.
71 */
72struct rtc_device *alarmtimer_get_rtcdev(void)
73{
74 unsigned long flags;
75 struct rtc_device *ret;
76
77 spin_lock_irqsave(&rtcdev_lock, flags);
78 ret = rtcdev;
79 spin_unlock_irqrestore(&rtcdev_lock, flags);
80
81 return ret;
82}
83EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
84
85static int alarmtimer_rtc_add_device(struct device *dev,
86 struct class_interface *class_intf)
87{
88 unsigned long flags;
89 struct rtc_device *rtc = to_rtc_device(dev);
90 struct wakeup_source *__ws;
91
92 if (rtcdev)
93 return -EBUSY;
94
95 if (!rtc->ops->set_alarm)
96 return -1;
97 if (!device_may_wakeup(rtc->dev.parent))
98 return -1;
99
100 __ws = wakeup_source_register(dev, "alarmtimer");
101
102 spin_lock_irqsave(&rtcdev_lock, flags);
103 if (!rtcdev) {
104 if (!try_module_get(rtc->owner)) {
105 spin_unlock_irqrestore(&rtcdev_lock, flags);
106 return -1;
107 }
108
109 rtcdev = rtc;
110 /* hold a reference so it doesn't go away */
111 get_device(dev);
112 ws = __ws;
113 __ws = NULL;
114 }
115 spin_unlock_irqrestore(&rtcdev_lock, flags);
116
117 wakeup_source_unregister(__ws);
118
119 return 0;
120}
121
122static inline void alarmtimer_rtc_timer_init(void)
123{
124 rtc_timer_init(&rtctimer, NULL, NULL);
125}
126
127static struct class_interface alarmtimer_rtc_interface = {
128 .add_dev = &alarmtimer_rtc_add_device,
129};
130
131static int alarmtimer_rtc_interface_setup(void)
132{
133 alarmtimer_rtc_interface.class = rtc_class;
134 return class_interface_register(&alarmtimer_rtc_interface);
135}
136static void alarmtimer_rtc_interface_remove(void)
137{
138 class_interface_unregister(&alarmtimer_rtc_interface);
139}
140#else
141struct rtc_device *alarmtimer_get_rtcdev(void)
142{
143 return NULL;
144}
145#define rtcdev (NULL)
146static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
147static inline void alarmtimer_rtc_interface_remove(void) { }
148static inline void alarmtimer_rtc_timer_init(void) { }
149#endif
150
151/**
152 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
153 * @base: pointer to the base where the timer is being run
154 * @alarm: pointer to alarm being enqueued.
155 *
156 * Adds alarm to a alarm_base timerqueue
157 *
158 * Must hold base->lock when calling.
159 */
160static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
161{
162 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
163 timerqueue_del(&base->timerqueue, &alarm->node);
164
165 timerqueue_add(&base->timerqueue, &alarm->node);
166 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
167}
168
169/**
170 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
171 * @base: pointer to the base where the timer is running
172 * @alarm: pointer to alarm being removed
173 *
174 * Removes alarm to a alarm_base timerqueue
175 *
176 * Must hold base->lock when calling.
177 */
178static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
179{
180 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
181 return;
182
183 timerqueue_del(&base->timerqueue, &alarm->node);
184 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
185}
186
187
188/**
189 * alarmtimer_fired - Handles alarm hrtimer being fired.
190 * @timer: pointer to hrtimer being run
191 *
192 * When a alarm timer fires, this runs through the timerqueue to
193 * see which alarms expired, and runs those. If there are more alarm
194 * timers queued for the future, we set the hrtimer to fire when
195 * when the next future alarm timer expires.
196 */
197static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
198{
199 struct alarm *alarm = container_of(timer, struct alarm, timer);
200 struct alarm_base *base = &alarm_bases[alarm->type];
201 unsigned long flags;
202 int ret = HRTIMER_NORESTART;
203 int restart = ALARMTIMER_NORESTART;
204
205 spin_lock_irqsave(&base->lock, flags);
206 alarmtimer_dequeue(base, alarm);
207 spin_unlock_irqrestore(&base->lock, flags);
208
209 if (alarm->function)
210 restart = alarm->function(alarm, base->gettime());
211
212 spin_lock_irqsave(&base->lock, flags);
213 if (restart != ALARMTIMER_NORESTART) {
214 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
215 alarmtimer_enqueue(base, alarm);
216 ret = HRTIMER_RESTART;
217 }
218 spin_unlock_irqrestore(&base->lock, flags);
219
220 trace_alarmtimer_fired(alarm, base->gettime());
221 return ret;
222
223}
224
225ktime_t alarm_expires_remaining(const struct alarm *alarm)
226{
227 struct alarm_base *base = &alarm_bases[alarm->type];
228 return ktime_sub(alarm->node.expires, base->gettime());
229}
230EXPORT_SYMBOL_GPL(alarm_expires_remaining);
231
232#ifdef CONFIG_RTC_CLASS
233/**
234 * alarmtimer_suspend - Suspend time callback
235 * @dev: unused
236 *
237 * When we are going into suspend, we look through the bases
238 * to see which is the soonest timer to expire. We then
239 * set an rtc timer to fire that far into the future, which
240 * will wake us from suspend.
241 */
242static int alarmtimer_suspend(struct device *dev)
243{
244 ktime_t min, now, expires;
245 int i, ret, type;
246 struct rtc_device *rtc;
247 unsigned long flags;
248 struct rtc_time tm;
249
250 spin_lock_irqsave(&freezer_delta_lock, flags);
251 min = freezer_delta;
252 expires = freezer_expires;
253 type = freezer_alarmtype;
254 freezer_delta = 0;
255 spin_unlock_irqrestore(&freezer_delta_lock, flags);
256
257 rtc = alarmtimer_get_rtcdev();
258 /* If we have no rtcdev, just return */
259 if (!rtc)
260 return 0;
261
262 /* Find the soonest timer to expire*/
263 for (i = 0; i < ALARM_NUMTYPE; i++) {
264 struct alarm_base *base = &alarm_bases[i];
265 struct timerqueue_node *next;
266 ktime_t delta;
267
268 spin_lock_irqsave(&base->lock, flags);
269 next = timerqueue_getnext(&base->timerqueue);
270 spin_unlock_irqrestore(&base->lock, flags);
271 if (!next)
272 continue;
273 delta = ktime_sub(next->expires, base->gettime());
274 if (!min || (delta < min)) {
275 expires = next->expires;
276 min = delta;
277 type = i;
278 }
279 }
280 if (min == 0)
281 return 0;
282
283 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
284 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
285 return -EBUSY;
286 }
287
288 trace_alarmtimer_suspend(expires, type);
289
290 /* Setup an rtc timer to fire that far in the future */
291 rtc_timer_cancel(rtc, &rtctimer);
292 rtc_read_time(rtc, &tm);
293 now = rtc_tm_to_ktime(tm);
294 now = ktime_add(now, min);
295
296 /* Set alarm, if in the past reject suspend briefly to handle */
297 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
298 if (ret < 0)
299 __pm_wakeup_event(ws, MSEC_PER_SEC);
300 return ret;
301}
302
303static int alarmtimer_resume(struct device *dev)
304{
305 struct rtc_device *rtc;
306
307 rtc = alarmtimer_get_rtcdev();
308 if (rtc)
309 rtc_timer_cancel(rtc, &rtctimer);
310 return 0;
311}
312
313#else
314static int alarmtimer_suspend(struct device *dev)
315{
316 return 0;
317}
318
319static int alarmtimer_resume(struct device *dev)
320{
321 return 0;
322}
323#endif
324
325static void
326__alarm_init(struct alarm *alarm, enum alarmtimer_type type,
327 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
328{
329 timerqueue_init(&alarm->node);
330 alarm->timer.function = alarmtimer_fired;
331 alarm->function = function;
332 alarm->type = type;
333 alarm->state = ALARMTIMER_STATE_INACTIVE;
334}
335
336/**
337 * alarm_init - Initialize an alarm structure
338 * @alarm: ptr to alarm to be initialized
339 * @type: the type of the alarm
340 * @function: callback that is run when the alarm fires
341 */
342void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
343 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
344{
345 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
346 HRTIMER_MODE_ABS);
347 __alarm_init(alarm, type, function);
348}
349EXPORT_SYMBOL_GPL(alarm_init);
350
351/**
352 * alarm_start - Sets an absolute alarm to fire
353 * @alarm: ptr to alarm to set
354 * @start: time to run the alarm
355 */
356void alarm_start(struct alarm *alarm, ktime_t start)
357{
358 struct alarm_base *base = &alarm_bases[alarm->type];
359 unsigned long flags;
360
361 spin_lock_irqsave(&base->lock, flags);
362 alarm->node.expires = start;
363 alarmtimer_enqueue(base, alarm);
364 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
365 spin_unlock_irqrestore(&base->lock, flags);
366
367 trace_alarmtimer_start(alarm, base->gettime());
368}
369EXPORT_SYMBOL_GPL(alarm_start);
370
371/**
372 * alarm_start_relative - Sets a relative alarm to fire
373 * @alarm: ptr to alarm to set
374 * @start: time relative to now to run the alarm
375 */
376void alarm_start_relative(struct alarm *alarm, ktime_t start)
377{
378 struct alarm_base *base = &alarm_bases[alarm->type];
379
380 start = ktime_add_safe(start, base->gettime());
381 alarm_start(alarm, start);
382}
383EXPORT_SYMBOL_GPL(alarm_start_relative);
384
385void alarm_restart(struct alarm *alarm)
386{
387 struct alarm_base *base = &alarm_bases[alarm->type];
388 unsigned long flags;
389
390 spin_lock_irqsave(&base->lock, flags);
391 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
392 hrtimer_restart(&alarm->timer);
393 alarmtimer_enqueue(base, alarm);
394 spin_unlock_irqrestore(&base->lock, flags);
395}
396EXPORT_SYMBOL_GPL(alarm_restart);
397
398/**
399 * alarm_try_to_cancel - Tries to cancel an alarm timer
400 * @alarm: ptr to alarm to be canceled
401 *
402 * Returns 1 if the timer was canceled, 0 if it was not running,
403 * and -1 if the callback was running
404 */
405int alarm_try_to_cancel(struct alarm *alarm)
406{
407 struct alarm_base *base = &alarm_bases[alarm->type];
408 unsigned long flags;
409 int ret;
410
411 spin_lock_irqsave(&base->lock, flags);
412 ret = hrtimer_try_to_cancel(&alarm->timer);
413 if (ret >= 0)
414 alarmtimer_dequeue(base, alarm);
415 spin_unlock_irqrestore(&base->lock, flags);
416
417 trace_alarmtimer_cancel(alarm, base->gettime());
418 return ret;
419}
420EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
421
422
423/**
424 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
425 * @alarm: ptr to alarm to be canceled
426 *
427 * Returns 1 if the timer was canceled, 0 if it was not active.
428 */
429int alarm_cancel(struct alarm *alarm)
430{
431 for (;;) {
432 int ret = alarm_try_to_cancel(alarm);
433 if (ret >= 0)
434 return ret;
435 hrtimer_cancel_wait_running(&alarm->timer);
436 }
437}
438EXPORT_SYMBOL_GPL(alarm_cancel);
439
440
441u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
442{
443 u64 overrun = 1;
444 ktime_t delta;
445
446 delta = ktime_sub(now, alarm->node.expires);
447
448 if (delta < 0)
449 return 0;
450
451 if (unlikely(delta >= interval)) {
452 s64 incr = ktime_to_ns(interval);
453
454 overrun = ktime_divns(delta, incr);
455
456 alarm->node.expires = ktime_add_ns(alarm->node.expires,
457 incr*overrun);
458
459 if (alarm->node.expires > now)
460 return overrun;
461 /*
462 * This (and the ktime_add() below) is the
463 * correction for exact:
464 */
465 overrun++;
466 }
467
468 alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
469 return overrun;
470}
471EXPORT_SYMBOL_GPL(alarm_forward);
472
473u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
474{
475 struct alarm_base *base = &alarm_bases[alarm->type];
476
477 return alarm_forward(alarm, base->gettime(), interval);
478}
479EXPORT_SYMBOL_GPL(alarm_forward_now);
480
481#ifdef CONFIG_POSIX_TIMERS
482
483static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
484{
485 struct alarm_base *base;
486 unsigned long flags;
487 ktime_t delta;
488
489 switch(type) {
490 case ALARM_REALTIME:
491 base = &alarm_bases[ALARM_REALTIME];
492 type = ALARM_REALTIME_FREEZER;
493 break;
494 case ALARM_BOOTTIME:
495 base = &alarm_bases[ALARM_BOOTTIME];
496 type = ALARM_BOOTTIME_FREEZER;
497 break;
498 default:
499 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
500 return;
501 }
502
503 delta = ktime_sub(absexp, base->gettime());
504
505 spin_lock_irqsave(&freezer_delta_lock, flags);
506 if (!freezer_delta || (delta < freezer_delta)) {
507 freezer_delta = delta;
508 freezer_expires = absexp;
509 freezer_alarmtype = type;
510 }
511 spin_unlock_irqrestore(&freezer_delta_lock, flags);
512}
513
514/**
515 * clock2alarm - helper that converts from clockid to alarmtypes
516 * @clockid: clockid.
517 */
518static enum alarmtimer_type clock2alarm(clockid_t clockid)
519{
520 if (clockid == CLOCK_REALTIME_ALARM)
521 return ALARM_REALTIME;
522 if (clockid == CLOCK_BOOTTIME_ALARM)
523 return ALARM_BOOTTIME;
524 return -1;
525}
526
527/**
528 * alarm_handle_timer - Callback for posix timers
529 * @alarm: alarm that fired
530 *
531 * Posix timer callback for expired alarm timers.
532 */
533static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
534 ktime_t now)
535{
536 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
537 it.alarm.alarmtimer);
538 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
539 unsigned long flags;
540 int si_private = 0;
541
542 spin_lock_irqsave(&ptr->it_lock, flags);
543
544 ptr->it_active = 0;
545 if (ptr->it_interval)
546 si_private = ++ptr->it_requeue_pending;
547
548 if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
549 /*
550 * Handle ignored signals and rearm the timer. This will go
551 * away once we handle ignored signals proper.
552 */
553 ptr->it_overrun += alarm_forward_now(alarm, ptr->it_interval);
554 ++ptr->it_requeue_pending;
555 ptr->it_active = 1;
556 result = ALARMTIMER_RESTART;
557 }
558 spin_unlock_irqrestore(&ptr->it_lock, flags);
559
560 return result;
561}
562
563/**
564 * alarm_timer_rearm - Posix timer callback for rearming timer
565 * @timr: Pointer to the posixtimer data struct
566 */
567static void alarm_timer_rearm(struct k_itimer *timr)
568{
569 struct alarm *alarm = &timr->it.alarm.alarmtimer;
570
571 timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
572 alarm_start(alarm, alarm->node.expires);
573}
574
575/**
576 * alarm_timer_forward - Posix timer callback for forwarding timer
577 * @timr: Pointer to the posixtimer data struct
578 * @now: Current time to forward the timer against
579 */
580static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
581{
582 struct alarm *alarm = &timr->it.alarm.alarmtimer;
583
584 return alarm_forward(alarm, timr->it_interval, now);
585}
586
587/**
588 * alarm_timer_remaining - Posix timer callback to retrieve remaining time
589 * @timr: Pointer to the posixtimer data struct
590 * @now: Current time to calculate against
591 */
592static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
593{
594 struct alarm *alarm = &timr->it.alarm.alarmtimer;
595
596 return ktime_sub(alarm->node.expires, now);
597}
598
599/**
600 * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
601 * @timr: Pointer to the posixtimer data struct
602 */
603static int alarm_timer_try_to_cancel(struct k_itimer *timr)
604{
605 return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
606}
607
608/**
609 * alarm_timer_wait_running - Posix timer callback to wait for a timer
610 * @timr: Pointer to the posixtimer data struct
611 *
612 * Called from the core code when timer cancel detected that the callback
613 * is running. @timr is unlocked and rcu read lock is held to prevent it
614 * from being freed.
615 */
616static void alarm_timer_wait_running(struct k_itimer *timr)
617{
618 hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
619}
620
621/**
622 * alarm_timer_arm - Posix timer callback to arm a timer
623 * @timr: Pointer to the posixtimer data struct
624 * @expires: The new expiry time
625 * @absolute: Expiry value is absolute time
626 * @sigev_none: Posix timer does not deliver signals
627 */
628static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
629 bool absolute, bool sigev_none)
630{
631 struct alarm *alarm = &timr->it.alarm.alarmtimer;
632 struct alarm_base *base = &alarm_bases[alarm->type];
633
634 if (!absolute)
635 expires = ktime_add_safe(expires, base->gettime());
636 if (sigev_none)
637 alarm->node.expires = expires;
638 else
639 alarm_start(&timr->it.alarm.alarmtimer, expires);
640}
641
642/**
643 * alarm_clock_getres - posix getres interface
644 * @which_clock: clockid
645 * @tp: timespec to fill
646 *
647 * Returns the granularity of underlying alarm base clock
648 */
649static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
650{
651 if (!alarmtimer_get_rtcdev())
652 return -EINVAL;
653
654 tp->tv_sec = 0;
655 tp->tv_nsec = hrtimer_resolution;
656 return 0;
657}
658
659/**
660 * alarm_clock_get - posix clock_get interface
661 * @which_clock: clockid
662 * @tp: timespec to fill.
663 *
664 * Provides the underlying alarm base time.
665 */
666static int alarm_clock_get(clockid_t which_clock, struct timespec64 *tp)
667{
668 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
669
670 if (!alarmtimer_get_rtcdev())
671 return -EINVAL;
672
673 *tp = ktime_to_timespec64(base->gettime());
674 return 0;
675}
676
677/**
678 * alarm_timer_create - posix timer_create interface
679 * @new_timer: k_itimer pointer to manage
680 *
681 * Initializes the k_itimer structure.
682 */
683static int alarm_timer_create(struct k_itimer *new_timer)
684{
685 enum alarmtimer_type type;
686
687 if (!alarmtimer_get_rtcdev())
688 return -EOPNOTSUPP;
689
690 if (!capable(CAP_WAKE_ALARM))
691 return -EPERM;
692
693 type = clock2alarm(new_timer->it_clock);
694 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
695 return 0;
696}
697
698/**
699 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
700 * @alarm: ptr to alarm that fired
701 *
702 * Wakes up the task that set the alarmtimer
703 */
704static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
705 ktime_t now)
706{
707 struct task_struct *task = (struct task_struct *)alarm->data;
708
709 alarm->data = NULL;
710 if (task)
711 wake_up_process(task);
712 return ALARMTIMER_NORESTART;
713}
714
715/**
716 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
717 * @alarm: ptr to alarmtimer
718 * @absexp: absolute expiration time
719 *
720 * Sets the alarm timer and sleeps until it is fired or interrupted.
721 */
722static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
723 enum alarmtimer_type type)
724{
725 struct restart_block *restart;
726 alarm->data = (void *)current;
727 do {
728 set_current_state(TASK_INTERRUPTIBLE);
729 alarm_start(alarm, absexp);
730 if (likely(alarm->data))
731 schedule();
732
733 alarm_cancel(alarm);
734 } while (alarm->data && !signal_pending(current));
735
736 __set_current_state(TASK_RUNNING);
737
738 destroy_hrtimer_on_stack(&alarm->timer);
739
740 if (!alarm->data)
741 return 0;
742
743 if (freezing(current))
744 alarmtimer_freezerset(absexp, type);
745 restart = ¤t->restart_block;
746 if (restart->nanosleep.type != TT_NONE) {
747 struct timespec64 rmt;
748 ktime_t rem;
749
750 rem = ktime_sub(absexp, alarm_bases[type].gettime());
751
752 if (rem <= 0)
753 return 0;
754 rmt = ktime_to_timespec64(rem);
755
756 return nanosleep_copyout(restart, &rmt);
757 }
758 return -ERESTART_RESTARTBLOCK;
759}
760
761static void
762alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
763 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
764{
765 hrtimer_init_on_stack(&alarm->timer, alarm_bases[type].base_clockid,
766 HRTIMER_MODE_ABS);
767 __alarm_init(alarm, type, function);
768}
769
770/**
771 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
772 * @restart: ptr to restart block
773 *
774 * Handles restarted clock_nanosleep calls
775 */
776static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
777{
778 enum alarmtimer_type type = restart->nanosleep.clockid;
779 ktime_t exp = restart->nanosleep.expires;
780 struct alarm alarm;
781
782 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
783
784 return alarmtimer_do_nsleep(&alarm, exp, type);
785}
786
787/**
788 * alarm_timer_nsleep - alarmtimer nanosleep
789 * @which_clock: clockid
790 * @flags: determins abstime or relative
791 * @tsreq: requested sleep time (abs or rel)
792 * @rmtp: remaining sleep time saved
793 *
794 * Handles clock_nanosleep calls against _ALARM clockids
795 */
796static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
797 const struct timespec64 *tsreq)
798{
799 enum alarmtimer_type type = clock2alarm(which_clock);
800 struct restart_block *restart = ¤t->restart_block;
801 struct alarm alarm;
802 ktime_t exp;
803 int ret = 0;
804
805 if (!alarmtimer_get_rtcdev())
806 return -EOPNOTSUPP;
807
808 if (flags & ~TIMER_ABSTIME)
809 return -EINVAL;
810
811 if (!capable(CAP_WAKE_ALARM))
812 return -EPERM;
813
814 alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
815
816 exp = timespec64_to_ktime(*tsreq);
817 /* Convert (if necessary) to absolute time */
818 if (flags != TIMER_ABSTIME) {
819 ktime_t now = alarm_bases[type].gettime();
820
821 exp = ktime_add_safe(now, exp);
822 }
823
824 ret = alarmtimer_do_nsleep(&alarm, exp, type);
825 if (ret != -ERESTART_RESTARTBLOCK)
826 return ret;
827
828 /* abs timers don't set remaining time or restart */
829 if (flags == TIMER_ABSTIME)
830 return -ERESTARTNOHAND;
831
832 restart->fn = alarm_timer_nsleep_restart;
833 restart->nanosleep.clockid = type;
834 restart->nanosleep.expires = exp;
835 return ret;
836}
837
838const struct k_clock alarm_clock = {
839 .clock_getres = alarm_clock_getres,
840 .clock_get = alarm_clock_get,
841 .timer_create = alarm_timer_create,
842 .timer_set = common_timer_set,
843 .timer_del = common_timer_del,
844 .timer_get = common_timer_get,
845 .timer_arm = alarm_timer_arm,
846 .timer_rearm = alarm_timer_rearm,
847 .timer_forward = alarm_timer_forward,
848 .timer_remaining = alarm_timer_remaining,
849 .timer_try_to_cancel = alarm_timer_try_to_cancel,
850 .timer_wait_running = alarm_timer_wait_running,
851 .nsleep = alarm_timer_nsleep,
852};
853#endif /* CONFIG_POSIX_TIMERS */
854
855
856/* Suspend hook structures */
857static const struct dev_pm_ops alarmtimer_pm_ops = {
858 .suspend = alarmtimer_suspend,
859 .resume = alarmtimer_resume,
860};
861
862static struct platform_driver alarmtimer_driver = {
863 .driver = {
864 .name = "alarmtimer",
865 .pm = &alarmtimer_pm_ops,
866 }
867};
868
869/**
870 * alarmtimer_init - Initialize alarm timer code
871 *
872 * This function initializes the alarm bases and registers
873 * the posix clock ids.
874 */
875static int __init alarmtimer_init(void)
876{
877 struct platform_device *pdev;
878 int error = 0;
879 int i;
880
881 alarmtimer_rtc_timer_init();
882
883 /* Initialize alarm bases */
884 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
885 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
886 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
887 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
888 for (i = 0; i < ALARM_NUMTYPE; i++) {
889 timerqueue_init_head(&alarm_bases[i].timerqueue);
890 spin_lock_init(&alarm_bases[i].lock);
891 }
892
893 error = alarmtimer_rtc_interface_setup();
894 if (error)
895 return error;
896
897 error = platform_driver_register(&alarmtimer_driver);
898 if (error)
899 goto out_if;
900
901 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
902 if (IS_ERR(pdev)) {
903 error = PTR_ERR(pdev);
904 goto out_drv;
905 }
906 return 0;
907
908out_drv:
909 platform_driver_unregister(&alarmtimer_driver);
910out_if:
911 alarmtimer_rtc_interface_remove();
912 return error;
913}
914device_initcall(alarmtimer_init);
1/*
2 * Alarmtimer interface
3 *
4 * This interface provides a timer which is similarto hrtimers,
5 * but triggers a RTC alarm if the box is suspend.
6 *
7 * This interface is influenced by the Android RTC Alarm timer
8 * interface.
9 *
10 * Copyright (C) 2010 IBM Corperation
11 *
12 * Author: John Stultz <john.stultz@linaro.org>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License version 2 as
16 * published by the Free Software Foundation.
17 */
18#include <linux/time.h>
19#include <linux/hrtimer.h>
20#include <linux/timerqueue.h>
21#include <linux/rtc.h>
22#include <linux/alarmtimer.h>
23#include <linux/mutex.h>
24#include <linux/platform_device.h>
25#include <linux/posix-timers.h>
26#include <linux/workqueue.h>
27#include <linux/freezer.h>
28
29/**
30 * struct alarm_base - Alarm timer bases
31 * @lock: Lock for syncrhonized access to the base
32 * @timerqueue: Timerqueue head managing the list of events
33 * @timer: hrtimer used to schedule events while running
34 * @gettime: Function to read the time correlating to the base
35 * @base_clockid: clockid for the base
36 */
37static struct alarm_base {
38 spinlock_t lock;
39 struct timerqueue_head timerqueue;
40 struct hrtimer timer;
41 ktime_t (*gettime)(void);
42 clockid_t base_clockid;
43} alarm_bases[ALARM_NUMTYPE];
44
45/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
46static ktime_t freezer_delta;
47static DEFINE_SPINLOCK(freezer_delta_lock);
48
49#ifdef CONFIG_RTC_CLASS
50/* rtc timer and device for setting alarm wakeups at suspend */
51static struct rtc_timer rtctimer;
52static struct rtc_device *rtcdev;
53static DEFINE_SPINLOCK(rtcdev_lock);
54
55/**
56 * alarmtimer_get_rtcdev - Return selected rtcdevice
57 *
58 * This function returns the rtc device to use for wakealarms.
59 * If one has not already been chosen, it checks to see if a
60 * functional rtc device is available.
61 */
62struct rtc_device *alarmtimer_get_rtcdev(void)
63{
64 unsigned long flags;
65 struct rtc_device *ret;
66
67 spin_lock_irqsave(&rtcdev_lock, flags);
68 ret = rtcdev;
69 spin_unlock_irqrestore(&rtcdev_lock, flags);
70
71 return ret;
72}
73
74
75static int alarmtimer_rtc_add_device(struct device *dev,
76 struct class_interface *class_intf)
77{
78 unsigned long flags;
79 struct rtc_device *rtc = to_rtc_device(dev);
80
81 if (rtcdev)
82 return -EBUSY;
83
84 if (!rtc->ops->set_alarm)
85 return -1;
86 if (!device_may_wakeup(rtc->dev.parent))
87 return -1;
88
89 spin_lock_irqsave(&rtcdev_lock, flags);
90 if (!rtcdev) {
91 rtcdev = rtc;
92 /* hold a reference so it doesn't go away */
93 get_device(dev);
94 }
95 spin_unlock_irqrestore(&rtcdev_lock, flags);
96 return 0;
97}
98
99static inline void alarmtimer_rtc_timer_init(void)
100{
101 rtc_timer_init(&rtctimer, NULL, NULL);
102}
103
104static struct class_interface alarmtimer_rtc_interface = {
105 .add_dev = &alarmtimer_rtc_add_device,
106};
107
108static int alarmtimer_rtc_interface_setup(void)
109{
110 alarmtimer_rtc_interface.class = rtc_class;
111 return class_interface_register(&alarmtimer_rtc_interface);
112}
113static void alarmtimer_rtc_interface_remove(void)
114{
115 class_interface_unregister(&alarmtimer_rtc_interface);
116}
117#else
118struct rtc_device *alarmtimer_get_rtcdev(void)
119{
120 return NULL;
121}
122#define rtcdev (NULL)
123static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
124static inline void alarmtimer_rtc_interface_remove(void) { }
125static inline void alarmtimer_rtc_timer_init(void) { }
126#endif
127
128/**
129 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
130 * @base: pointer to the base where the timer is being run
131 * @alarm: pointer to alarm being enqueued.
132 *
133 * Adds alarm to a alarm_base timerqueue and if necessary sets
134 * an hrtimer to run.
135 *
136 * Must hold base->lock when calling.
137 */
138static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
139{
140 timerqueue_add(&base->timerqueue, &alarm->node);
141 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
142
143 if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
144 hrtimer_try_to_cancel(&base->timer);
145 hrtimer_start(&base->timer, alarm->node.expires,
146 HRTIMER_MODE_ABS);
147 }
148}
149
150/**
151 * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
152 * @base: pointer to the base where the timer is running
153 * @alarm: pointer to alarm being removed
154 *
155 * Removes alarm to a alarm_base timerqueue and if necessary sets
156 * a new timer to run.
157 *
158 * Must hold base->lock when calling.
159 */
160static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
161{
162 struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);
163
164 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
165 return;
166
167 timerqueue_del(&base->timerqueue, &alarm->node);
168 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
169
170 if (next == &alarm->node) {
171 hrtimer_try_to_cancel(&base->timer);
172 next = timerqueue_getnext(&base->timerqueue);
173 if (!next)
174 return;
175 hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);
176 }
177}
178
179
180/**
181 * alarmtimer_fired - Handles alarm hrtimer being fired.
182 * @timer: pointer to hrtimer being run
183 *
184 * When a alarm timer fires, this runs through the timerqueue to
185 * see which alarms expired, and runs those. If there are more alarm
186 * timers queued for the future, we set the hrtimer to fire when
187 * when the next future alarm timer expires.
188 */
189static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
190{
191 struct alarm_base *base = container_of(timer, struct alarm_base, timer);
192 struct timerqueue_node *next;
193 unsigned long flags;
194 ktime_t now;
195 int ret = HRTIMER_NORESTART;
196 int restart = ALARMTIMER_NORESTART;
197
198 spin_lock_irqsave(&base->lock, flags);
199 now = base->gettime();
200 while ((next = timerqueue_getnext(&base->timerqueue))) {
201 struct alarm *alarm;
202 ktime_t expired = next->expires;
203
204 if (expired.tv64 > now.tv64)
205 break;
206
207 alarm = container_of(next, struct alarm, node);
208
209 timerqueue_del(&base->timerqueue, &alarm->node);
210 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
211
212 alarm->state |= ALARMTIMER_STATE_CALLBACK;
213 spin_unlock_irqrestore(&base->lock, flags);
214 if (alarm->function)
215 restart = alarm->function(alarm, now);
216 spin_lock_irqsave(&base->lock, flags);
217 alarm->state &= ~ALARMTIMER_STATE_CALLBACK;
218
219 if (restart != ALARMTIMER_NORESTART) {
220 timerqueue_add(&base->timerqueue, &alarm->node);
221 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
222 }
223 }
224
225 if (next) {
226 hrtimer_set_expires(&base->timer, next->expires);
227 ret = HRTIMER_RESTART;
228 }
229 spin_unlock_irqrestore(&base->lock, flags);
230
231 return ret;
232
233}
234
235#ifdef CONFIG_RTC_CLASS
236/**
237 * alarmtimer_suspend - Suspend time callback
238 * @dev: unused
239 * @state: unused
240 *
241 * When we are going into suspend, we look through the bases
242 * to see which is the soonest timer to expire. We then
243 * set an rtc timer to fire that far into the future, which
244 * will wake us from suspend.
245 */
246static int alarmtimer_suspend(struct device *dev)
247{
248 struct rtc_time tm;
249 ktime_t min, now;
250 unsigned long flags;
251 struct rtc_device *rtc;
252 int i;
253
254 spin_lock_irqsave(&freezer_delta_lock, flags);
255 min = freezer_delta;
256 freezer_delta = ktime_set(0, 0);
257 spin_unlock_irqrestore(&freezer_delta_lock, flags);
258
259 rtc = alarmtimer_get_rtcdev();
260 /* If we have no rtcdev, just return */
261 if (!rtc)
262 return 0;
263
264 /* Find the soonest timer to expire*/
265 for (i = 0; i < ALARM_NUMTYPE; i++) {
266 struct alarm_base *base = &alarm_bases[i];
267 struct timerqueue_node *next;
268 ktime_t delta;
269
270 spin_lock_irqsave(&base->lock, flags);
271 next = timerqueue_getnext(&base->timerqueue);
272 spin_unlock_irqrestore(&base->lock, flags);
273 if (!next)
274 continue;
275 delta = ktime_sub(next->expires, base->gettime());
276 if (!min.tv64 || (delta.tv64 < min.tv64))
277 min = delta;
278 }
279 if (min.tv64 == 0)
280 return 0;
281
282 /* XXX - Should we enforce a minimum sleep time? */
283 WARN_ON(min.tv64 < NSEC_PER_SEC);
284
285 /* Setup an rtc timer to fire that far in the future */
286 rtc_timer_cancel(rtc, &rtctimer);
287 rtc_read_time(rtc, &tm);
288 now = rtc_tm_to_ktime(tm);
289 now = ktime_add(now, min);
290
291 rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
292
293 return 0;
294}
295#else
296static int alarmtimer_suspend(struct device *dev)
297{
298 return 0;
299}
300#endif
301
302static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
303{
304 ktime_t delta;
305 unsigned long flags;
306 struct alarm_base *base = &alarm_bases[type];
307
308 delta = ktime_sub(absexp, base->gettime());
309
310 spin_lock_irqsave(&freezer_delta_lock, flags);
311 if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
312 freezer_delta = delta;
313 spin_unlock_irqrestore(&freezer_delta_lock, flags);
314}
315
316
317/**
318 * alarm_init - Initialize an alarm structure
319 * @alarm: ptr to alarm to be initialized
320 * @type: the type of the alarm
321 * @function: callback that is run when the alarm fires
322 */
323void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
324 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
325{
326 timerqueue_init(&alarm->node);
327 alarm->function = function;
328 alarm->type = type;
329 alarm->state = ALARMTIMER_STATE_INACTIVE;
330}
331
332/**
333 * alarm_start - Sets an alarm to fire
334 * @alarm: ptr to alarm to set
335 * @start: time to run the alarm
336 */
337void alarm_start(struct alarm *alarm, ktime_t start)
338{
339 struct alarm_base *base = &alarm_bases[alarm->type];
340 unsigned long flags;
341
342 spin_lock_irqsave(&base->lock, flags);
343 if (alarmtimer_active(alarm))
344 alarmtimer_remove(base, alarm);
345 alarm->node.expires = start;
346 alarmtimer_enqueue(base, alarm);
347 spin_unlock_irqrestore(&base->lock, flags);
348}
349
350/**
351 * alarm_try_to_cancel - Tries to cancel an alarm timer
352 * @alarm: ptr to alarm to be canceled
353 *
354 * Returns 1 if the timer was canceled, 0 if it was not running,
355 * and -1 if the callback was running
356 */
357int alarm_try_to_cancel(struct alarm *alarm)
358{
359 struct alarm_base *base = &alarm_bases[alarm->type];
360 unsigned long flags;
361 int ret = -1;
362 spin_lock_irqsave(&base->lock, flags);
363
364 if (alarmtimer_callback_running(alarm))
365 goto out;
366
367 if (alarmtimer_is_queued(alarm)) {
368 alarmtimer_remove(base, alarm);
369 ret = 1;
370 } else
371 ret = 0;
372out:
373 spin_unlock_irqrestore(&base->lock, flags);
374 return ret;
375}
376
377
378/**
379 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
380 * @alarm: ptr to alarm to be canceled
381 *
382 * Returns 1 if the timer was canceled, 0 if it was not active.
383 */
384int alarm_cancel(struct alarm *alarm)
385{
386 for (;;) {
387 int ret = alarm_try_to_cancel(alarm);
388 if (ret >= 0)
389 return ret;
390 cpu_relax();
391 }
392}
393
394
395u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
396{
397 u64 overrun = 1;
398 ktime_t delta;
399
400 delta = ktime_sub(now, alarm->node.expires);
401
402 if (delta.tv64 < 0)
403 return 0;
404
405 if (unlikely(delta.tv64 >= interval.tv64)) {
406 s64 incr = ktime_to_ns(interval);
407
408 overrun = ktime_divns(delta, incr);
409
410 alarm->node.expires = ktime_add_ns(alarm->node.expires,
411 incr*overrun);
412
413 if (alarm->node.expires.tv64 > now.tv64)
414 return overrun;
415 /*
416 * This (and the ktime_add() below) is the
417 * correction for exact:
418 */
419 overrun++;
420 }
421
422 alarm->node.expires = ktime_add(alarm->node.expires, interval);
423 return overrun;
424}
425
426
427
428
429/**
430 * clock2alarm - helper that converts from clockid to alarmtypes
431 * @clockid: clockid.
432 */
433static enum alarmtimer_type clock2alarm(clockid_t clockid)
434{
435 if (clockid == CLOCK_REALTIME_ALARM)
436 return ALARM_REALTIME;
437 if (clockid == CLOCK_BOOTTIME_ALARM)
438 return ALARM_BOOTTIME;
439 return -1;
440}
441
442/**
443 * alarm_handle_timer - Callback for posix timers
444 * @alarm: alarm that fired
445 *
446 * Posix timer callback for expired alarm timers.
447 */
448static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
449 ktime_t now)
450{
451 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
452 it.alarm.alarmtimer);
453 if (posix_timer_event(ptr, 0) != 0)
454 ptr->it_overrun++;
455
456 /* Re-add periodic timers */
457 if (ptr->it.alarm.interval.tv64) {
458 ptr->it_overrun += alarm_forward(alarm, now,
459 ptr->it.alarm.interval);
460 return ALARMTIMER_RESTART;
461 }
462 return ALARMTIMER_NORESTART;
463}
464
465/**
466 * alarm_clock_getres - posix getres interface
467 * @which_clock: clockid
468 * @tp: timespec to fill
469 *
470 * Returns the granularity of underlying alarm base clock
471 */
472static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
473{
474 clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
475
476 if (!alarmtimer_get_rtcdev())
477 return -ENOTSUPP;
478
479 return hrtimer_get_res(baseid, tp);
480}
481
482/**
483 * alarm_clock_get - posix clock_get interface
484 * @which_clock: clockid
485 * @tp: timespec to fill.
486 *
487 * Provides the underlying alarm base time.
488 */
489static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
490{
491 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
492
493 if (!alarmtimer_get_rtcdev())
494 return -ENOTSUPP;
495
496 *tp = ktime_to_timespec(base->gettime());
497 return 0;
498}
499
500/**
501 * alarm_timer_create - posix timer_create interface
502 * @new_timer: k_itimer pointer to manage
503 *
504 * Initializes the k_itimer structure.
505 */
506static int alarm_timer_create(struct k_itimer *new_timer)
507{
508 enum alarmtimer_type type;
509 struct alarm_base *base;
510
511 if (!alarmtimer_get_rtcdev())
512 return -ENOTSUPP;
513
514 if (!capable(CAP_WAKE_ALARM))
515 return -EPERM;
516
517 type = clock2alarm(new_timer->it_clock);
518 base = &alarm_bases[type];
519 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
520 return 0;
521}
522
523/**
524 * alarm_timer_get - posix timer_get interface
525 * @new_timer: k_itimer pointer
526 * @cur_setting: itimerspec data to fill
527 *
528 * Copies the itimerspec data out from the k_itimer
529 */
530static void alarm_timer_get(struct k_itimer *timr,
531 struct itimerspec *cur_setting)
532{
533 memset(cur_setting, 0, sizeof(struct itimerspec));
534
535 cur_setting->it_interval =
536 ktime_to_timespec(timr->it.alarm.interval);
537 cur_setting->it_value =
538 ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
539 return;
540}
541
542/**
543 * alarm_timer_del - posix timer_del interface
544 * @timr: k_itimer pointer to be deleted
545 *
546 * Cancels any programmed alarms for the given timer.
547 */
548static int alarm_timer_del(struct k_itimer *timr)
549{
550 if (!rtcdev)
551 return -ENOTSUPP;
552
553 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
554 return TIMER_RETRY;
555
556 return 0;
557}
558
559/**
560 * alarm_timer_set - posix timer_set interface
561 * @timr: k_itimer pointer to be deleted
562 * @flags: timer flags
563 * @new_setting: itimerspec to be used
564 * @old_setting: itimerspec being replaced
565 *
566 * Sets the timer to new_setting, and starts the timer.
567 */
568static int alarm_timer_set(struct k_itimer *timr, int flags,
569 struct itimerspec *new_setting,
570 struct itimerspec *old_setting)
571{
572 if (!rtcdev)
573 return -ENOTSUPP;
574
575 if (old_setting)
576 alarm_timer_get(timr, old_setting);
577
578 /* If the timer was already set, cancel it */
579 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
580 return TIMER_RETRY;
581
582 /* start the timer */
583 timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
584 alarm_start(&timr->it.alarm.alarmtimer,
585 timespec_to_ktime(new_setting->it_value));
586 return 0;
587}
588
589/**
590 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
591 * @alarm: ptr to alarm that fired
592 *
593 * Wakes up the task that set the alarmtimer
594 */
595static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
596 ktime_t now)
597{
598 struct task_struct *task = (struct task_struct *)alarm->data;
599
600 alarm->data = NULL;
601 if (task)
602 wake_up_process(task);
603 return ALARMTIMER_NORESTART;
604}
605
606/**
607 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
608 * @alarm: ptr to alarmtimer
609 * @absexp: absolute expiration time
610 *
611 * Sets the alarm timer and sleeps until it is fired or interrupted.
612 */
613static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
614{
615 alarm->data = (void *)current;
616 do {
617 set_current_state(TASK_INTERRUPTIBLE);
618 alarm_start(alarm, absexp);
619 if (likely(alarm->data))
620 schedule();
621
622 alarm_cancel(alarm);
623 } while (alarm->data && !signal_pending(current));
624
625 __set_current_state(TASK_RUNNING);
626
627 return (alarm->data == NULL);
628}
629
630
631/**
632 * update_rmtp - Update remaining timespec value
633 * @exp: expiration time
634 * @type: timer type
635 * @rmtp: user pointer to remaining timepsec value
636 *
637 * Helper function that fills in rmtp value with time between
638 * now and the exp value
639 */
640static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
641 struct timespec __user *rmtp)
642{
643 struct timespec rmt;
644 ktime_t rem;
645
646 rem = ktime_sub(exp, alarm_bases[type].gettime());
647
648 if (rem.tv64 <= 0)
649 return 0;
650 rmt = ktime_to_timespec(rem);
651
652 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
653 return -EFAULT;
654
655 return 1;
656
657}
658
659/**
660 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
661 * @restart: ptr to restart block
662 *
663 * Handles restarted clock_nanosleep calls
664 */
665static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
666{
667 enum alarmtimer_type type = restart->nanosleep.clockid;
668 ktime_t exp;
669 struct timespec __user *rmtp;
670 struct alarm alarm;
671 int ret = 0;
672
673 exp.tv64 = restart->nanosleep.expires;
674 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
675
676 if (alarmtimer_do_nsleep(&alarm, exp))
677 goto out;
678
679 if (freezing(current))
680 alarmtimer_freezerset(exp, type);
681
682 rmtp = restart->nanosleep.rmtp;
683 if (rmtp) {
684 ret = update_rmtp(exp, type, rmtp);
685 if (ret <= 0)
686 goto out;
687 }
688
689
690 /* The other values in restart are already filled in */
691 ret = -ERESTART_RESTARTBLOCK;
692out:
693 return ret;
694}
695
696/**
697 * alarm_timer_nsleep - alarmtimer nanosleep
698 * @which_clock: clockid
699 * @flags: determins abstime or relative
700 * @tsreq: requested sleep time (abs or rel)
701 * @rmtp: remaining sleep time saved
702 *
703 * Handles clock_nanosleep calls against _ALARM clockids
704 */
705static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
706 struct timespec *tsreq, struct timespec __user *rmtp)
707{
708 enum alarmtimer_type type = clock2alarm(which_clock);
709 struct alarm alarm;
710 ktime_t exp;
711 int ret = 0;
712 struct restart_block *restart;
713
714 if (!alarmtimer_get_rtcdev())
715 return -ENOTSUPP;
716
717 if (!capable(CAP_WAKE_ALARM))
718 return -EPERM;
719
720 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
721
722 exp = timespec_to_ktime(*tsreq);
723 /* Convert (if necessary) to absolute time */
724 if (flags != TIMER_ABSTIME) {
725 ktime_t now = alarm_bases[type].gettime();
726 exp = ktime_add(now, exp);
727 }
728
729 if (alarmtimer_do_nsleep(&alarm, exp))
730 goto out;
731
732 if (freezing(current))
733 alarmtimer_freezerset(exp, type);
734
735 /* abs timers don't set remaining time or restart */
736 if (flags == TIMER_ABSTIME) {
737 ret = -ERESTARTNOHAND;
738 goto out;
739 }
740
741 if (rmtp) {
742 ret = update_rmtp(exp, type, rmtp);
743 if (ret <= 0)
744 goto out;
745 }
746
747 restart = ¤t_thread_info()->restart_block;
748 restart->fn = alarm_timer_nsleep_restart;
749 restart->nanosleep.clockid = type;
750 restart->nanosleep.expires = exp.tv64;
751 restart->nanosleep.rmtp = rmtp;
752 ret = -ERESTART_RESTARTBLOCK;
753
754out:
755 return ret;
756}
757
758
759/* Suspend hook structures */
760static const struct dev_pm_ops alarmtimer_pm_ops = {
761 .suspend = alarmtimer_suspend,
762};
763
764static struct platform_driver alarmtimer_driver = {
765 .driver = {
766 .name = "alarmtimer",
767 .pm = &alarmtimer_pm_ops,
768 }
769};
770
771/**
772 * alarmtimer_init - Initialize alarm timer code
773 *
774 * This function initializes the alarm bases and registers
775 * the posix clock ids.
776 */
777static int __init alarmtimer_init(void)
778{
779 struct platform_device *pdev;
780 int error = 0;
781 int i;
782 struct k_clock alarm_clock = {
783 .clock_getres = alarm_clock_getres,
784 .clock_get = alarm_clock_get,
785 .timer_create = alarm_timer_create,
786 .timer_set = alarm_timer_set,
787 .timer_del = alarm_timer_del,
788 .timer_get = alarm_timer_get,
789 .nsleep = alarm_timer_nsleep,
790 };
791
792 alarmtimer_rtc_timer_init();
793
794 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
795 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
796
797 /* Initialize alarm bases */
798 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
799 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
800 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
801 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
802 for (i = 0; i < ALARM_NUMTYPE; i++) {
803 timerqueue_init_head(&alarm_bases[i].timerqueue);
804 spin_lock_init(&alarm_bases[i].lock);
805 hrtimer_init(&alarm_bases[i].timer,
806 alarm_bases[i].base_clockid,
807 HRTIMER_MODE_ABS);
808 alarm_bases[i].timer.function = alarmtimer_fired;
809 }
810
811 error = alarmtimer_rtc_interface_setup();
812 if (error)
813 return error;
814
815 error = platform_driver_register(&alarmtimer_driver);
816 if (error)
817 goto out_if;
818
819 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
820 if (IS_ERR(pdev)) {
821 error = PTR_ERR(pdev);
822 goto out_drv;
823 }
824 return 0;
825
826out_drv:
827 platform_driver_unregister(&alarmtimer_driver);
828out_if:
829 alarmtimer_rtc_interface_remove();
830 return error;
831}
832device_initcall(alarmtimer_init);