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/* * Alarmtimer interface * * This interface provides a timer which is similarto hrtimers, * but triggers a RTC alarm if the box is suspend. * * This interface is influenced by the Android RTC Alarm timer * interface. * * Copyright (C) 2010 IBM Corperation * * Author: John Stultz <john.stultz@linaro.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */#include <linux/time.h>#include <linux/hrtimer.h>#include <linux/timerqueue.h>#include <linux/rtc.h>#include <linux/alarmtimer.h>#include <linux/mutex.h>#include <linux/platform_device.h>#include <linux/posix-timers.h>#include <linux/workqueue.h>#include <linux/freezer.h> /** * struct alarm_base - Alarm timer bases * @lock:		Lock for syncrhonized access to the base * @timerqueue:		Timerqueue head managing the list of events * @timer: 		hrtimer used to schedule events while running * @gettime:		Function to read the time correlating to the base * @base_clockid:	clockid for the base */static struct alarm_base {	spinlock_t		lock;	struct timerqueue_head	timerqueue;	struct hrtimer		timer;	ktime_t			(*gettime)(void);	clockid_t		base_clockid;} alarm_bases[ALARM_NUMTYPE]; /* freezer delta & lock used to handle clock_nanosleep triggered wakeups */static ktime_t freezer_delta;static DEFINE_SPINLOCK(freezer_delta_lock); #ifdef CONFIG_RTC_CLASS/* rtc timer and device for setting alarm wakeups at suspend */static struct rtc_timer		rtctimer;static struct rtc_device	*rtcdev;static DEFINE_SPINLOCK(rtcdev_lock); /** * has_wakealarm - check rtc device has wakealarm ability * @dev: current device * @name_ptr: name to be returned * * This helper function checks to see if the rtc device can wake * from suspend. */static int has_wakealarm(struct device *dev, void *name_ptr){	struct rtc_device *candidate = to_rtc_device(dev); 	if (!candidate->ops->set_alarm)		return 0;	if (!device_may_wakeup(candidate->dev.parent))		return 0; 	*(const char **)name_ptr = dev_name(dev);	return 1;} /** * alarmtimer_get_rtcdev - Return selected rtcdevice * * This function returns the rtc device to use for wakealarms. * If one has not already been chosen, it checks to see if a * functional rtc device is available. */static struct rtc_device *alarmtimer_get_rtcdev(void){	struct device *dev;	char *str;	unsigned long flags;	struct rtc_device *ret; 	spin_lock_irqsave(&rtcdev_lock, flags);	if (!rtcdev) {		/* Find an rtc device and init the rtc_timer */		dev = class_find_device(rtc_class, NULL, &str, has_wakealarm);		/* If we have a device then str is valid. See has_wakealarm() */		if (dev) {			rtcdev = rtc_class_open(str);			/*			 * Drop the reference we got in class_find_device,			 * rtc_open takes its own.			 */			put_device(dev);			rtc_timer_init(&rtctimer, NULL, NULL);		}	}	ret = rtcdev;	spin_unlock_irqrestore(&rtcdev_lock, flags); 	return ret;}#else#define alarmtimer_get_rtcdev() (0)#define rtcdev (0)#endif  /** * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue * @base: pointer to the base where the timer is being run * @alarm: pointer to alarm being enqueued. * * Adds alarm to a alarm_base timerqueue and if necessary sets * an hrtimer to run. * * Must hold base->lock when calling. */static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm){	timerqueue_add(&base->timerqueue, &alarm->node);	if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {		hrtimer_try_to_cancel(&base->timer);		hrtimer_start(&base->timer, alarm->node.expires,				HRTIMER_MODE_ABS);	}} /** * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue * @base: pointer to the base where the timer is running * @alarm: pointer to alarm being removed * * Removes alarm to a alarm_base timerqueue and if necessary sets * a new timer to run. * * Must hold base->lock when calling. */static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm){	struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue); 	timerqueue_del(&base->timerqueue, &alarm->node);	if (next == &alarm->node) {		hrtimer_try_to_cancel(&base->timer);		next = timerqueue_getnext(&base->timerqueue);		if (!next)			return;		hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);	}}  /** * alarmtimer_fired - Handles alarm hrtimer being fired. * @timer: pointer to hrtimer being run * * When a alarm timer fires, this runs through the timerqueue to * see which alarms expired, and runs those. If there are more alarm * timers queued for the future, we set the hrtimer to fire when * when the next future alarm timer expires. */static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer){	struct alarm_base *base = container_of(timer, struct alarm_base, timer);	struct timerqueue_node *next;	unsigned long flags;	ktime_t now;	int ret = HRTIMER_NORESTART; 	spin_lock_irqsave(&base->lock, flags);	now = base->gettime();	while ((next = timerqueue_getnext(&base->timerqueue))) {		struct alarm *alarm;		ktime_t expired = next->expires; 		if (expired.tv64 >= now.tv64)			break; 		alarm = container_of(next, struct alarm, node); 		timerqueue_del(&base->timerqueue, &alarm->node);		alarm->enabled = 0;		/* Re-add periodic timers */		if (alarm->period.tv64) {			alarm->node.expires = ktime_add(expired, alarm->period);			timerqueue_add(&base->timerqueue, &alarm->node);			alarm->enabled = 1;		}		spin_unlock_irqrestore(&base->lock, flags);		if (alarm->function)			alarm->function(alarm);		spin_lock_irqsave(&base->lock, flags);	} 	if (next) {		hrtimer_set_expires(&base->timer, next->expires);		ret = HRTIMER_RESTART;	}	spin_unlock_irqrestore(&base->lock, flags); 	return ret; } #ifdef CONFIG_RTC_CLASS/** * alarmtimer_suspend - Suspend time callback * @dev: unused * @state: unused * * When we are going into suspend, we look through the bases * to see which is the soonest timer to expire. We then * set an rtc timer to fire that far into the future, which * will wake us from suspend. */static int alarmtimer_suspend(struct device *dev){	struct rtc_time tm;	ktime_t min, now;	unsigned long flags;	struct rtc_device *rtc;	int i; 	spin_lock_irqsave(&freezer_delta_lock, flags);	min = freezer_delta;	freezer_delta = ktime_set(0, 0);	spin_unlock_irqrestore(&freezer_delta_lock, flags); 	rtc = rtcdev;	/* If we have no rtcdev, just return */	if (!rtc)		return 0; 	/* Find the soonest timer to expire*/	for (i = 0; i < ALARM_NUMTYPE; i++) {		struct alarm_base *base = &alarm_bases[i];		struct timerqueue_node *next;		ktime_t delta; 		spin_lock_irqsave(&base->lock, flags);		next = timerqueue_getnext(&base->timerqueue);		spin_unlock_irqrestore(&base->lock, flags);		if (!next)			continue;		delta = ktime_sub(next->expires, base->gettime());		if (!min.tv64 || (delta.tv64 < min.tv64))			min = delta;	}	if (min.tv64 == 0)		return 0; 	/* XXX - Should we enforce a minimum sleep time? */	WARN_ON(min.tv64 < NSEC_PER_SEC); 	/* Setup an rtc timer to fire that far in the future */	rtc_timer_cancel(rtc, &rtctimer);	rtc_read_time(rtc, &tm);	now = rtc_tm_to_ktime(tm);	now = ktime_add(now, min); 	rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0)); 	return 0;}#elsestatic int alarmtimer_suspend(struct device *dev){	return 0;}#endif static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type){	ktime_t delta;	unsigned long flags;	struct alarm_base *base = &alarm_bases[type]; 	delta = ktime_sub(absexp, base->gettime()); 	spin_lock_irqsave(&freezer_delta_lock, flags);	if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))		freezer_delta = delta;	spin_unlock_irqrestore(&freezer_delta_lock, flags);}  /** * alarm_init - Initialize an alarm structure * @alarm: ptr to alarm to be initialized * @type: the type of the alarm * @function: callback that is run when the alarm fires */void alarm_init(struct alarm *alarm, enum alarmtimer_type type,		void (*function)(struct alarm *)){	timerqueue_init(&alarm->node);	alarm->period = ktime_set(0, 0);	alarm->function = function;	alarm->type = type;	alarm->enabled = 0;} /** * alarm_start - Sets an alarm to fire * @alarm: ptr to alarm to set * @start: time to run the alarm * @period: period at which the alarm will recur */void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period){	struct alarm_base *base = &alarm_bases[alarm->type];	unsigned long flags; 	spin_lock_irqsave(&base->lock, flags);	if (alarm->enabled)		alarmtimer_remove(base, alarm);	alarm->node.expires = start;	alarm->period = period;	alarmtimer_enqueue(base, alarm);	alarm->enabled = 1;	spin_unlock_irqrestore(&base->lock, flags);} /** * alarm_cancel - Tries to cancel an alarm timer * @alarm: ptr to alarm to be canceled */void alarm_cancel(struct alarm *alarm){	struct alarm_base *base = &alarm_bases[alarm->type];	unsigned long flags; 	spin_lock_irqsave(&base->lock, flags);	if (alarm->enabled)		alarmtimer_remove(base, alarm);	alarm->enabled = 0;	spin_unlock_irqrestore(&base->lock, flags);}  /** * clock2alarm - helper that converts from clockid to alarmtypes * @clockid: clockid. */static enum alarmtimer_type clock2alarm(clockid_t clockid){	if (clockid == CLOCK_REALTIME_ALARM)		return ALARM_REALTIME;	if (clockid == CLOCK_BOOTTIME_ALARM)		return ALARM_BOOTTIME;	return -1;} /** * alarm_handle_timer - Callback for posix timers * @alarm: alarm that fired * * Posix timer callback for expired alarm timers. */static void alarm_handle_timer(struct alarm *alarm){	struct k_itimer *ptr = container_of(alarm, struct k_itimer,						it.alarmtimer);	if (posix_timer_event(ptr, 0) != 0)		ptr->it_overrun++;} /** * alarm_clock_getres - posix getres interface * @which_clock: clockid * @tp: timespec to fill * * Returns the granularity of underlying alarm base clock */static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp){	clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid; 	if (!alarmtimer_get_rtcdev())		return -ENOTSUPP; 	return hrtimer_get_res(baseid, tp);} /** * alarm_clock_get - posix clock_get interface * @which_clock: clockid * @tp: timespec to fill. * * Provides the underlying alarm base time. */static int alarm_clock_get(clockid_t which_clock, struct timespec *tp){	struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)]; 	if (!alarmtimer_get_rtcdev())		return -ENOTSUPP; 	*tp = ktime_to_timespec(base->gettime());	return 0;} /** * alarm_timer_create - posix timer_create interface * @new_timer: k_itimer pointer to manage * * Initializes the k_itimer structure. */static int alarm_timer_create(struct k_itimer *new_timer){	enum  alarmtimer_type type;	struct alarm_base *base; 	if (!alarmtimer_get_rtcdev())		return -ENOTSUPP; 	if (!capable(CAP_WAKE_ALARM))		return -EPERM; 	type = clock2alarm(new_timer->it_clock);	base = &alarm_bases[type];	alarm_init(&new_timer->it.alarmtimer, type, alarm_handle_timer);	return 0;} /** * alarm_timer_get - posix timer_get interface * @new_timer: k_itimer pointer * @cur_setting: itimerspec data to fill * * Copies the itimerspec data out from the k_itimer */static void alarm_timer_get(struct k_itimer *timr,				struct itimerspec *cur_setting){	cur_setting->it_interval =			ktime_to_timespec(timr->it.alarmtimer.period);	cur_setting->it_value =			ktime_to_timespec(timr->it.alarmtimer.node.expires);	return;} /** * alarm_timer_del - posix timer_del interface * @timr: k_itimer pointer to be deleted * * Cancels any programmed alarms for the given timer. */static int alarm_timer_del(struct k_itimer *timr){	if (!rtcdev)		return -ENOTSUPP; 	alarm_cancel(&timr->it.alarmtimer);	return 0;} /** * alarm_timer_set - posix timer_set interface * @timr: k_itimer pointer to be deleted * @flags: timer flags * @new_setting: itimerspec to be used * @old_setting: itimerspec being replaced * * Sets the timer to new_setting, and starts the timer. */static int alarm_timer_set(struct k_itimer *timr, int flags,				struct itimerspec *new_setting,				struct itimerspec *old_setting){	if (!rtcdev)		return -ENOTSUPP; 	/* Save old values */	old_setting->it_interval =			ktime_to_timespec(timr->it.alarmtimer.period);	old_setting->it_value =			ktime_to_timespec(timr->it.alarmtimer.node.expires); 	/* If the timer was already set, cancel it */	alarm_cancel(&timr->it.alarmtimer); 	/* start the timer */	alarm_start(&timr->it.alarmtimer,			timespec_to_ktime(new_setting->it_value),			timespec_to_ktime(new_setting->it_interval));	return 0;} /** * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep * @alarm: ptr to alarm that fired

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