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