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 = &current->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 = &current->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);