[deliverable/linux.git] / drivers / rtc / interface.c

/*
 * RTC subsystem, interface functions
 *
 * Copyright (C) 2005 Tower Technologies
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 *
 * based on arch/arm/common/rtctime.c
 *
 * 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/rtc.h>
#include <linux/sched.h>
#include <linux/log2.h>
#include <linux/workqueue.h>

static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);

static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
{
	int err;
	if (!rtc->ops)
		err = -ENODEV;
	else if (!rtc->ops->read_time)
		err = -EINVAL;
	else {
		memset(tm, 0, sizeof(struct rtc_time));
		err = rtc->ops->read_time(rtc->dev.parent, tm);
	}
	return err;
}

int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
{
	int err;

	err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;

	err = __rtc_read_time(rtc, tm);
	mutex_unlock(&rtc->ops_lock);
	return err;
}
EXPORT_SYMBOL_GPL(rtc_read_time);

int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
{
	int err;

	err = rtc_valid_tm(tm);
	if (err != 0)
		return err;

	err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;

	if (!rtc->ops)
		err = -ENODEV;
	else if (rtc->ops->set_time)
		err = rtc->ops->set_time(rtc->dev.parent, tm);
	else if (rtc->ops->set_mmss) {
		unsigned long secs;
		err = rtc_tm_to_time(tm, &secs);
		if (err == 0)
			err = rtc->ops->set_mmss(rtc->dev.parent, secs);
	} else
		err = -EINVAL;

	mutex_unlock(&rtc->ops_lock);
	return err;
}
EXPORT_SYMBOL_GPL(rtc_set_time);

int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
{
	int err;

	err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;

	if (!rtc->ops)
		err = -ENODEV;
	else if (rtc->ops->set_mmss)
		err = rtc->ops->set_mmss(rtc->dev.parent, secs);
	else if (rtc->ops->read_time && rtc->ops->set_time) {
		struct rtc_time new, old;

		err = rtc->ops->read_time(rtc->dev.parent, &old);
		if (err == 0) {
			rtc_time_to_tm(secs, &new);

			/*
			 * avoid writing when we're going to change the day of
			 * the month. We will retry in the next minute. This
			 * basically means that if the RTC must not drift
			 * by more than 1 minute in 11 minutes.
			 */
			if (!((old.tm_hour == 23 && old.tm_min == 59) ||
				(new.tm_hour == 23 && new.tm_min == 59)))
				err = rtc->ops->set_time(rtc->dev.parent,
						&new);
		}
	}
	else
		err = -EINVAL;

	mutex_unlock(&rtc->ops_lock);

	return err;
}
EXPORT_SYMBOL_GPL(rtc_set_mmss);

int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
	int err;

	err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;
	if (rtc->ops == NULL)
		err = -ENODEV;
	else if (!rtc->ops->read_alarm)
		err = -EINVAL;
	else {
		memset(alarm, 0, sizeof(struct rtc_wkalrm));
		alarm->enabled = rtc->aie_timer.enabled;
		alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
	}
	mutex_unlock(&rtc->ops_lock);

	return err;
}
EXPORT_SYMBOL_GPL(rtc_read_alarm);

int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
	struct rtc_time tm;
	long now, scheduled;
	int err;

	err = rtc_valid_tm(&alarm->time);
	if (err)
		return err;
	rtc_tm_to_time(&alarm->time, &scheduled);

	/* Make sure we're not setting alarms in the past */
	err = __rtc_read_time(rtc, &tm);
	rtc_tm_to_time(&tm, &now);
	if (scheduled <= now)
		return -ETIME;
	/*
	 * XXX - We just checked to make sure the alarm time is not
	 * in the past, but there is still a race window where if
	 * the is alarm set for the next second and the second ticks
	 * over right here, before we set the alarm.
	 */

	if (!rtc->ops)
		err = -ENODEV;
	else if (!rtc->ops->set_alarm)
		err = -EINVAL;
	else
		err = rtc->ops->set_alarm(rtc->dev.parent, alarm);

	return err;
}

int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
	int err;

	err = rtc_valid_tm(&alarm->time);
	if (err != 0)
		return err;

	err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;
	if (rtc->aie_timer.enabled) {
		rtc_timer_remove(rtc, &rtc->aie_timer);
	}
	rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
	rtc->aie_timer.period = ktime_set(0, 0);
	if (alarm->enabled) {
		err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
	}
	mutex_unlock(&rtc->ops_lock);
	return err;
}
EXPORT_SYMBOL_GPL(rtc_set_alarm);

int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
{
	int err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;

	if (rtc->aie_timer.enabled != enabled) {
		if (enabled)
			err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
		else
			rtc_timer_remove(rtc, &rtc->aie_timer);
	}

	if (err)
		/* nothing */;
	else if (!rtc->ops)
		err = -ENODEV;
	else if (!rtc->ops->alarm_irq_enable)
		err = -EINVAL;
	else
		err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);

	mutex_unlock(&rtc->ops_lock);
	return err;
}
EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);

int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
{
	int err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;

	/* make sure we're changing state */
	if (rtc->uie_rtctimer.enabled == enabled)
		goto out;

	if (enabled) {
		struct rtc_time tm;
		ktime_t now, onesec;

		__rtc_read_time(rtc, &tm);
		onesec = ktime_set(1, 0);
		now = rtc_tm_to_ktime(tm);
		rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
		rtc->uie_rtctimer.period = ktime_set(1, 0);
		err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
	} else
		rtc_timer_remove(rtc, &rtc->uie_rtctimer);

out:
	mutex_unlock(&rtc->ops_lock);
	return err;

}
EXPORT_SYMBOL_GPL(rtc_update_irq_enable);


/**
 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
 * @rtc: pointer to the rtc device
 *
 * This function is called when an AIE, UIE or PIE mode interrupt
 * has occured (or been emulated).
 *
 * Triggers the registered irq_task function callback.
 */
static void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
{
	unsigned long flags;

	/* mark one irq of the appropriate mode */
	spin_lock_irqsave(&rtc->irq_lock, flags);
	rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
	spin_unlock_irqrestore(&rtc->irq_lock, flags);

	/* call the task func */
	spin_lock_irqsave(&rtc->irq_task_lock, flags);
	if (rtc->irq_task)
		rtc->irq_task->func(rtc->irq_task->private_data);
	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);

	wake_up_interruptible(&rtc->irq_queue);
	kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
}


/**
 * rtc_aie_update_irq - AIE mode rtctimer hook
 * @private: pointer to the rtc_device
 *
 * This functions is called when the aie_timer expires.
 */
void rtc_aie_update_irq(void *private)
{
	struct rtc_device *rtc = (struct rtc_device *)private;
	rtc_handle_legacy_irq(rtc, 1, RTC_AF);
}


/**
 * rtc_uie_update_irq - UIE mode rtctimer hook
 * @private: pointer to the rtc_device
 *
 * This functions is called when the uie_timer expires.
 */
void rtc_uie_update_irq(void *private)
{
	struct rtc_device *rtc = (struct rtc_device *)private;
	rtc_handle_legacy_irq(rtc, 1,  RTC_UF);
}


/**
 * rtc_pie_update_irq - PIE mode hrtimer hook
 * @timer: pointer to the pie mode hrtimer
 *
 * This function is used to emulate PIE mode interrupts
 * using an hrtimer. This function is called when the periodic
 * hrtimer expires.
 */
enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
{
	struct rtc_device *rtc;
	ktime_t period;
	int count;
	rtc = container_of(timer, struct rtc_device, pie_timer);

	period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
	count = hrtimer_forward_now(timer, period);

	rtc_handle_legacy_irq(rtc, count, RTC_PF);

	return HRTIMER_RESTART;
}

/**
 * rtc_update_irq - Triggered when a RTC interrupt occurs.
 * @rtc: the rtc device
 * @num: how many irqs are being reported (usually one)
 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
 * Context: any
 */
void rtc_update_irq(struct rtc_device *rtc,
		unsigned long num, unsigned long events)
{
	schedule_work(&rtc->irqwork);
}
EXPORT_SYMBOL_GPL(rtc_update_irq);

static int __rtc_match(struct device *dev, void *data)
{
	char *name = (char *)data;

	if (strcmp(dev_name(dev), name) == 0)
		return 1;
	return 0;
}

struct rtc_device *rtc_class_open(char *name)
{
	struct device *dev;
	struct rtc_device *rtc = NULL;

	dev = class_find_device(rtc_class, NULL, name, __rtc_match);
	if (dev)
		rtc = to_rtc_device(dev);

	if (rtc) {
		if (!try_module_get(rtc->owner)) {
			put_device(dev);
			rtc = NULL;
		}
	}

	return rtc;
}
EXPORT_SYMBOL_GPL(rtc_class_open);

void rtc_class_close(struct rtc_device *rtc)
{
	module_put(rtc->owner);
	put_device(&rtc->dev);
}
EXPORT_SYMBOL_GPL(rtc_class_close);

int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
{
	int retval = -EBUSY;

	if (task == NULL || task->func == NULL)
		return -EINVAL;

	/* Cannot register while the char dev is in use */
	if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
		return -EBUSY;

	spin_lock_irq(&rtc->irq_task_lock);
	if (rtc->irq_task == NULL) {
		rtc->irq_task = task;
		retval = 0;
	}
	spin_unlock_irq(&rtc->irq_task_lock);

	clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);

	return retval;
}
EXPORT_SYMBOL_GPL(rtc_irq_register);

void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
{
	spin_lock_irq(&rtc->irq_task_lock);
	if (rtc->irq_task == task)
		rtc->irq_task = NULL;
	spin_unlock_irq(&rtc->irq_task_lock);
}
EXPORT_SYMBOL_GPL(rtc_irq_unregister);

/**
 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
 * @rtc: the rtc device
 * @task: currently registered with rtc_irq_register()
 * @enabled: true to enable periodic IRQs
 * Context: any
 *
 * Note that rtc_irq_set_freq() should previously have been used to
 * specify the desired frequency of periodic IRQ task->func() callbacks.
 */
int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
{
	int err = 0;
	unsigned long flags;

	spin_lock_irqsave(&rtc->irq_task_lock, flags);
	if (rtc->irq_task != NULL && task == NULL)
		err = -EBUSY;
	if (rtc->irq_task != task)
		err = -EACCES;

	if (enabled) {
		ktime_t period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
		hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
	} else {
		hrtimer_cancel(&rtc->pie_timer);
	}
	rtc->pie_enabled = enabled;
	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);

	return err;
}
EXPORT_SYMBOL_GPL(rtc_irq_set_state);

/**
 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
 * @rtc: the rtc device
 * @task: currently registered with rtc_irq_register()
 * @freq: positive frequency with which task->func() will be called
 * Context: any
 *
 * Note that rtc_irq_set_state() is used to enable or disable the
 * periodic IRQs.
 */
int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
{
	int err = 0;
	unsigned long flags;

	if (freq <= 0)
		return -EINVAL;

	spin_lock_irqsave(&rtc->irq_task_lock, flags);
	if (rtc->irq_task != NULL && task == NULL)
		err = -EBUSY;
	if (rtc->irq_task != task)
		err = -EACCES;
	if (err == 0) {
		rtc->irq_freq = freq;
		if (rtc->pie_enabled) {
			ktime_t period;
			hrtimer_cancel(&rtc->pie_timer);
			period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
			hrtimer_start(&rtc->pie_timer, period,
					HRTIMER_MODE_REL);
		}
	}
	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
	return err;
}
EXPORT_SYMBOL_GPL(rtc_irq_set_freq);

/**
 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
 * @rtc rtc device
 * @timer timer being added.
 *
 * Enqueues a timer onto the rtc devices timerqueue and sets
 * the next alarm event appropriately.
 *
 * Sets the enabled bit on the added timer.
 *
 * Must hold ops_lock for proper serialization of timerqueue
 */
static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
{
	timer->enabled = 1;
	timerqueue_add(&rtc->timerqueue, &timer->node);
	if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
		struct rtc_wkalrm alarm;
		int err;
		alarm.time = rtc_ktime_to_tm(timer->node.expires);
		alarm.enabled = 1;
		err = __rtc_set_alarm(rtc, &alarm);
		if (err == -ETIME)
			schedule_work(&rtc->irqwork);
		else if (err) {
			timerqueue_del(&rtc->timerqueue, &timer->node);
			timer->enabled = 0;
			return err;
		}
	}
	return 0;
}

/**
 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
 * @rtc rtc device
 * @timer timer being removed.
 *
 * Removes a timer onto the rtc devices timerqueue and sets
 * the next alarm event appropriately.
 *
 * Clears the enabled bit on the removed timer.
 *
 * Must hold ops_lock for proper serialization of timerqueue
 */
static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
{
	struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
	timerqueue_del(&rtc->timerqueue, &timer->node);
	timer->enabled = 0;
	if (next == &timer->node) {
		struct rtc_wkalrm alarm;
		int err;
		next = timerqueue_getnext(&rtc->timerqueue);
		if (!next)
			return;
		alarm.time = rtc_ktime_to_tm(next->expires);
		alarm.enabled = 1;
		err = __rtc_set_alarm(rtc, &alarm);
		if (err == -ETIME)
			schedule_work(&rtc->irqwork);
	}
}

/**
 * rtc_timer_do_work - Expires rtc timers
 * @rtc rtc device
 * @timer timer being removed.
 *
 * Expires rtc timers. Reprograms next alarm event if needed.
 * Called via worktask.
 *
 * Serializes access to timerqueue via ops_lock mutex
 */
void rtc_timer_do_work(struct work_struct *work)
{
	struct rtc_timer *timer;
	struct timerqueue_node *next;
	ktime_t now;
	struct rtc_time tm;

	struct rtc_device *rtc =
		container_of(work, struct rtc_device, irqwork);

	mutex_lock(&rtc->ops_lock);
again:
	__rtc_read_time(rtc, &tm);
	now = rtc_tm_to_ktime(tm);
	while ((next = timerqueue_getnext(&rtc->timerqueue))) {
		if (next->expires.tv64 > now.tv64)
			break;

		/* expire timer */
		timer = container_of(next, struct rtc_timer, node);
		timerqueue_del(&rtc->timerqueue, &timer->node);
		timer->enabled = 0;
		if (timer->task.func)
			timer->task.func(timer->task.private_data);

		/* Re-add/fwd periodic timers */
		if (ktime_to_ns(timer->period)) {
			timer->node.expires = ktime_add(timer->node.expires,
							timer->period);
			timer->enabled = 1;
			timerqueue_add(&rtc->timerqueue, &timer->node);
		}
	}

	/* Set next alarm */
	if (next) {
		struct rtc_wkalrm alarm;
		int err;
		alarm.time = rtc_ktime_to_tm(next->expires);
		alarm.enabled = 1;
		err = __rtc_set_alarm(rtc, &alarm);
		if (err == -ETIME)
			goto again;
	}

	mutex_unlock(&rtc->ops_lock);
}


/* rtc_timer_init - Initializes an rtc_timer
 * @timer: timer to be intiialized
 * @f: function pointer to be called when timer fires
 * @data: private data passed to function pointer
 *
 * Kernel interface to initializing an rtc_timer.
 */
void rtc_timer_init(struct rtc_timer *timer, void (*f)(void* p), void* data)
{
	timerqueue_init(&timer->node);
	timer->enabled = 0;
	timer->task.func = f;
	timer->task.private_data = data;
}

/* rtc_timer_start - Sets an rtc_timer to fire in the future
 * @ rtc: rtc device to be used
 * @ timer: timer being set
 * @ expires: time at which to expire the timer
 * @ period: period that the timer will recur
 *
 * Kernel interface to set an rtc_timer
 */
int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer,
			ktime_t expires, ktime_t period)
{
	int ret = 0;
	mutex_lock(&rtc->ops_lock);
	if (timer->enabled)
		rtc_timer_remove(rtc, timer);

	timer->node.expires = expires;
	timer->period = period;

	ret = rtc_timer_enqueue(rtc, timer);

	mutex_unlock(&rtc->ops_lock);
	return ret;
}

/* rtc_timer_cancel - Stops an rtc_timer
 * @ rtc: rtc device to be used
 * @ timer: timer being set
 *
 * Kernel interface to cancel an rtc_timer
 */
int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer)
{
	int ret = 0;
	mutex_lock(&rtc->ops_lock);
	if (timer->enabled)
		rtc_timer_remove(rtc, timer);
	mutex_unlock(&rtc->ops_lock);
	return ret;
}
Commit	Line	Data
0c86edc0 AZ	1	/*
	2	* RTC subsystem, interface functions
	3	*
	4	* Copyright (C) 2005 Tower Technologies
	5	* Author: Alessandro Zummo <a.zummo@towertech.it>
	6	*
	7	* based on arch/arm/common/rtctime.c
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License version 2 as
	11	* published by the Free Software Foundation.
	12	*/
	13
	14	#include <linux/rtc.h>
d43c36dc	15	#include <linux/sched.h>
97144c67	16	#include <linux/log2.h>
6610e089	17	#include <linux/workqueue.h>
0c86edc0	18
aa0be0f4 JS	19	static int rtc_timer_enqueue(struct rtc_device rtc, struct rtc_timer timer);
	20	static void rtc_timer_remove(struct rtc_device rtc, struct rtc_timer timer);
	21
6610e089	22	static int __rtc_read_time(struct rtc_device rtc, struct rtc_time tm)
0c86edc0 AZ	23	{
0c86edc0 AZ	24	int err;
0c86edc0 AZ	25	if (!rtc->ops)
	26	err = -ENODEV;
	27	else if (!rtc->ops->read_time)
	28	err = -EINVAL;
	29	else {
	30	memset(tm, 0, sizeof(struct rtc_time));
cd966209	31	err = rtc->ops->read_time(rtc->dev.parent, tm);
0c86edc0	32	}
6610e089 JS	33	return err;
	34	}
	35
	36	int rtc_read_time(struct rtc_device rtc, struct rtc_time tm)
	37	{
	38	int err;
0c86edc0	39
6610e089 JS	40	err = mutex_lock_interruptible(&rtc->ops_lock);
	41	if (err)
	42	return err;
	43
	44	err = __rtc_read_time(rtc, tm);
0c86edc0 AZ	45	mutex_unlock(&rtc->ops_lock);
	46	return err;
	47	}
	48	EXPORT_SYMBOL_GPL(rtc_read_time);
	49
ab6a2d70	50	int rtc_set_time(struct rtc_device rtc, struct rtc_time tm)
0c86edc0 AZ	51	{
0c86edc0 AZ	52	int err;
0c86edc0 AZ	53
	54	err = rtc_valid_tm(tm);
	55	if (err != 0)
	56	return err;
	57
	58	err = mutex_lock_interruptible(&rtc->ops_lock);
	59	if (err)
b68bb263	60	return err;
0c86edc0 AZ	61
	62	if (!rtc->ops)
	63	err = -ENODEV;
bbccf83f	64	else if (rtc->ops->set_time)
cd966209	65	err = rtc->ops->set_time(rtc->dev.parent, tm);
bbccf83f AZ	66	else if (rtc->ops->set_mmss) {
	67	unsigned long secs;
	68	err = rtc_tm_to_time(tm, &secs);
	69	if (err == 0)
	70	err = rtc->ops->set_mmss(rtc->dev.parent, secs);
	71	} else
	72	err = -EINVAL;
0c86edc0 AZ	73
	74	mutex_unlock(&rtc->ops_lock);
	75	return err;
	76	}
	77	EXPORT_SYMBOL_GPL(rtc_set_time);
	78
ab6a2d70	79	int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
0c86edc0 AZ	80	{
0c86edc0 AZ	81	int err;
0c86edc0 AZ	82
	83	err = mutex_lock_interruptible(&rtc->ops_lock);
	84	if (err)
b68bb263	85	return err;
0c86edc0 AZ	86
	87	if (!rtc->ops)
	88	err = -ENODEV;
	89	else if (rtc->ops->set_mmss)
cd966209	90	err = rtc->ops->set_mmss(rtc->dev.parent, secs);
0c86edc0 AZ	91	else if (rtc->ops->read_time && rtc->ops->set_time) {
	92	struct rtc_time new, old;
	93
cd966209	94	err = rtc->ops->read_time(rtc->dev.parent, &old);
0c86edc0 AZ	95	if (err == 0) {
	96	rtc_time_to_tm(secs, &new);
	97
	98	/*
	99	* avoid writing when we're going to change the day of
	100	* the month. We will retry in the next minute. This
	101	* basically means that if the RTC must not drift
	102	* by more than 1 minute in 11 minutes.
	103	*/
	104	if (!((old.tm_hour == 23 && old.tm_min == 59) \|\|
	105	(new.tm_hour == 23 && new.tm_min == 59)))
cd966209	106	err = rtc->ops->set_time(rtc->dev.parent,
ab6a2d70	107	&new);
0c86edc0 AZ	108	}
	109	}
	110	else
	111	err = -EINVAL;
	112
	113	mutex_unlock(&rtc->ops_lock);
	114
	115	return err;
	116	}
	117	EXPORT_SYMBOL_GPL(rtc_set_mmss);
	118
6610e089	119	int rtc_read_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
0c86edc0 AZ	120	{
0c86edc0 AZ	121	int err;
0c86edc0 AZ	122
	123	err = mutex_lock_interruptible(&rtc->ops_lock);
	124	if (err)
b68bb263	125	return err;
d5553a55 JS	126	if (rtc->ops == NULL)
	127	err = -ENODEV;
	128	else if (!rtc->ops->read_alarm)
	129	err = -EINVAL;
	130	else {
	131	memset(alarm, 0, sizeof(struct rtc_wkalrm));
	132	alarm->enabled = rtc->aie_timer.enabled;
6610e089	133	alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
d5553a55	134	}
0c86edc0	135	mutex_unlock(&rtc->ops_lock);
6610e089	136
d5553a55	137	return err;
0c86edc0	138	}
6610e089	139	EXPORT_SYMBOL_GPL(rtc_read_alarm);
0e36a9a4	140
6610e089	141	int __rtc_set_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
0e36a9a4	142	{
6610e089 JS	143	struct rtc_time tm;
6610e089 JS	144	long now, scheduled;
0e36a9a4	145	int err;
0e36a9a4	146
6610e089 JS	147	err = rtc_valid_tm(&alarm->time);
6610e089 JS	148	if (err)
0e36a9a4	149	return err;
6610e089	150	rtc_tm_to_time(&alarm->time, &scheduled);
a01cc657	151
6610e089 JS	152	/* Make sure we're not setting alarms in the past */
	153	err = __rtc_read_time(rtc, &tm);
	154	rtc_tm_to_time(&tm, &now);
	155	if (scheduled <= now)
	156	return -ETIME;
	157	/*
	158	* XXX - We just checked to make sure the alarm time is not
	159	* in the past, but there is still a race window where if
	160	* the is alarm set for the next second and the second ticks
	161	* over right here, before we set the alarm.
a01cc657	162	*/
a01cc657	163
6610e089 JS	164	if (!rtc->ops)
	165	err = -ENODEV;
	166	else if (!rtc->ops->set_alarm)
	167	err = -EINVAL;
	168	else
	169	err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
	170
	171	return err;
0e36a9a4	172	}
0c86edc0	173
ab6a2d70	174	int rtc_set_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
0c86edc0 AZ	175	{
0c86edc0 AZ	176	int err;
0c86edc0	177
f8245c26 DB	178	err = rtc_valid_tm(&alarm->time);
	179	if (err != 0)
	180	return err;
	181
0c86edc0 AZ	182	err = mutex_lock_interruptible(&rtc->ops_lock);
0c86edc0 AZ	183	if (err)
b68bb263	184	return err;
6610e089	185	if (rtc->aie_timer.enabled) {
96c8f06a	186	rtc_timer_remove(rtc, &rtc->aie_timer);
6610e089 JS	187	}
	188	rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
	189	rtc->aie_timer.period = ktime_set(0, 0);
	190	if (alarm->enabled) {
aa0be0f4	191	err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
6610e089	192	}
0c86edc0	193	mutex_unlock(&rtc->ops_lock);
aa0be0f4	194	return err;
0c86edc0 AZ	195	}
	196	EXPORT_SYMBOL_GPL(rtc_set_alarm);
	197
099e6576 AZ	198	int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
	199	{
	200	int err = mutex_lock_interruptible(&rtc->ops_lock);
	201	if (err)
	202	return err;
	203
6610e089	204	if (rtc->aie_timer.enabled != enabled) {
aa0be0f4 JS	205	if (enabled)
	206	err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
	207	else
96c8f06a	208	rtc_timer_remove(rtc, &rtc->aie_timer);
6610e089 JS	209	}
6610e089 JS	210
aa0be0f4	211	if (err)
516373b8 UKK	212	/* nothing */;
516373b8 UKK	213	else if (!rtc->ops)
099e6576 AZ	214	err = -ENODEV;
	215	else if (!rtc->ops->alarm_irq_enable)
	216	err = -EINVAL;
	217	else
	218	err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
	219
	220	mutex_unlock(&rtc->ops_lock);
	221	return err;
	222	}
	223	EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
	224
	225	int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
	226	{
	227	int err = mutex_lock_interruptible(&rtc->ops_lock);
	228	if (err)
	229	return err;
	230
6610e089 JS	231	/* make sure we're changing state */
	232	if (rtc->uie_rtctimer.enabled == enabled)
	233	goto out;
	234
	235	if (enabled) {
	236	struct rtc_time tm;
	237	ktime_t now, onesec;
	238
	239	__rtc_read_time(rtc, &tm);
	240	onesec = ktime_set(1, 0);
	241	now = rtc_tm_to_ktime(tm);
	242	rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
	243	rtc->uie_rtctimer.period = ktime_set(1, 0);
aa0be0f4 JS	244	err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
aa0be0f4 JS	245	} else
96c8f06a	246	rtc_timer_remove(rtc, &rtc->uie_rtctimer);
099e6576	247
6610e089	248	out:
099e6576	249	mutex_unlock(&rtc->ops_lock);
099e6576	250	return err;
6610e089	251
099e6576 AZ	252	}
	253	EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
	254
6610e089	255
d728b1e6	256	/**
6610e089 JS	257	* rtc_handle_legacy_irq - AIE, UIE and PIE event hook
	258	* @rtc: pointer to the rtc device
	259	*
	260	* This function is called when an AIE, UIE or PIE mode interrupt
	261	* has occured (or been emulated).
	262	*
	263	* Triggers the registered irq_task function callback.
d728b1e6	264	*/
6610e089	265	static void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
0c86edc0	266	{
e6229bec AN	267	unsigned long flags;
e6229bec AN	268
6610e089	269	/* mark one irq of the appropriate mode */
e6229bec	270	spin_lock_irqsave(&rtc->irq_lock, flags);
6610e089	271	rtc->irq_data = (rtc->irq_data + (num << 8)) \| (RTC_IRQF\|mode);
e6229bec	272	spin_unlock_irqrestore(&rtc->irq_lock, flags);
0c86edc0	273
6610e089	274	/* call the task func */
e6229bec	275	spin_lock_irqsave(&rtc->irq_task_lock, flags);
0c86edc0 AZ	276	if (rtc->irq_task)
0c86edc0 AZ	277	rtc->irq_task->func(rtc->irq_task->private_data);
e6229bec	278	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
0c86edc0 AZ	279
	280	wake_up_interruptible(&rtc->irq_queue);
	281	kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
	282	}
6610e089 JS	283
	284
	285	/**
	286	* rtc_aie_update_irq - AIE mode rtctimer hook
	287	* @private: pointer to the rtc_device
	288	*
	289	* This functions is called when the aie_timer expires.
	290	*/
	291	void rtc_aie_update_irq(void *private)
	292	{
	293	struct rtc_device rtc = (struct rtc_device )private;
	294	rtc_handle_legacy_irq(rtc, 1, RTC_AF);
	295	}
	296
	297
	298	/**
	299	* rtc_uie_update_irq - UIE mode rtctimer hook
	300	* @private: pointer to the rtc_device
	301	*
	302	* This functions is called when the uie_timer expires.
	303	*/
	304	void rtc_uie_update_irq(void *private)
	305	{
	306	struct rtc_device rtc = (struct rtc_device )private;
	307	rtc_handle_legacy_irq(rtc, 1, RTC_UF);
	308	}
	309
	310
	311	/**
	312	* rtc_pie_update_irq - PIE mode hrtimer hook
	313	* @timer: pointer to the pie mode hrtimer
	314	*
	315	* This function is used to emulate PIE mode interrupts
	316	* using an hrtimer. This function is called when the periodic
	317	* hrtimer expires.
	318	*/
	319	enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
	320	{
	321	struct rtc_device *rtc;
	322	ktime_t period;
	323	int count;
	324	rtc = container_of(timer, struct rtc_device, pie_timer);
	325
	326	period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
	327	count = hrtimer_forward_now(timer, period);
	328
	329	rtc_handle_legacy_irq(rtc, count, RTC_PF);
	330
	331	return HRTIMER_RESTART;
	332	}
	333
	334	/**
	335	* rtc_update_irq - Triggered when a RTC interrupt occurs.
	336	* @rtc: the rtc device
	337	* @num: how many irqs are being reported (usually one)
	338	* @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
	339	* Context: any
	340	*/
	341	void rtc_update_irq(struct rtc_device *rtc,
	342	unsigned long num, unsigned long events)
	343	{
	344	schedule_work(&rtc->irqwork);
	345	}
0c86edc0 AZ	346	EXPORT_SYMBOL_GPL(rtc_update_irq);
0c86edc0 AZ	347
71da8905 DY	348	static int __rtc_match(struct device dev, void data)
	349	{
	350	char name = (char )data;
	351
d4afc76c	352	if (strcmp(dev_name(dev), name) == 0)
71da8905 DY	353	return 1;
	354	return 0;
	355	}
	356
ab6a2d70	357	struct rtc_device rtc_class_open(char name)
0c86edc0	358	{
cd966209	359	struct device *dev;
ab6a2d70	360	struct rtc_device *rtc = NULL;
0c86edc0	361
695794ae	362	dev = class_find_device(rtc_class, NULL, name, __rtc_match);
71da8905 DY	363	if (dev)
71da8905 DY	364	rtc = to_rtc_device(dev);
0c86edc0	365
ab6a2d70 DB	366	if (rtc) {
ab6a2d70 DB	367	if (!try_module_get(rtc->owner)) {
cd966209	368	put_device(dev);
ab6a2d70 DB	369	rtc = NULL;
ab6a2d70 DB	370	}
0c86edc0	371	}
0c86edc0	372
ab6a2d70	373	return rtc;
0c86edc0 AZ	374	}
	375	EXPORT_SYMBOL_GPL(rtc_class_open);
	376
ab6a2d70	377	void rtc_class_close(struct rtc_device *rtc)
0c86edc0	378	{
ab6a2d70	379	module_put(rtc->owner);
cd966209	380	put_device(&rtc->dev);
0c86edc0 AZ	381	}
	382	EXPORT_SYMBOL_GPL(rtc_class_close);
	383
ab6a2d70	384	int rtc_irq_register(struct rtc_device rtc, struct rtc_task task)
0c86edc0 AZ	385	{
0c86edc0 AZ	386	int retval = -EBUSY;
0c86edc0 AZ	387
	388	if (task == NULL \|\| task->func == NULL)
	389	return -EINVAL;
	390
d691eb90	391	/* Cannot register while the char dev is in use */
372a302e	392	if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
d691eb90 AZ	393	return -EBUSY;
d691eb90 AZ	394
d728b1e6	395	spin_lock_irq(&rtc->irq_task_lock);
0c86edc0 AZ	396	if (rtc->irq_task == NULL) {
	397	rtc->irq_task = task;
	398	retval = 0;
	399	}
d728b1e6	400	spin_unlock_irq(&rtc->irq_task_lock);
0c86edc0	401
372a302e	402	clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
d691eb90	403
0c86edc0 AZ	404	return retval;
	405	}
	406	EXPORT_SYMBOL_GPL(rtc_irq_register);
	407
ab6a2d70	408	void rtc_irq_unregister(struct rtc_device rtc, struct rtc_task task)
0c86edc0	409	{
d728b1e6	410	spin_lock_irq(&rtc->irq_task_lock);
0c86edc0 AZ	411	if (rtc->irq_task == task)
0c86edc0 AZ	412	rtc->irq_task = NULL;
d728b1e6	413	spin_unlock_irq(&rtc->irq_task_lock);
0c86edc0 AZ	414	}
	415	EXPORT_SYMBOL_GPL(rtc_irq_unregister);
	416
97144c67 DB	417	/**
	418	* rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
	419	* @rtc: the rtc device
	420	* @task: currently registered with rtc_irq_register()
	421	* @enabled: true to enable periodic IRQs
	422	* Context: any
	423	*
	424	* Note that rtc_irq_set_freq() should previously have been used to
	425	* specify the desired frequency of periodic IRQ task->func() callbacks.
	426	*/
ab6a2d70	427	int rtc_irq_set_state(struct rtc_device rtc, struct rtc_task task, int enabled)
0c86edc0 AZ	428	{
	429	int err = 0;
	430	unsigned long flags;
0c86edc0 AZ	431
0c86edc0 AZ	432	spin_lock_irqsave(&rtc->irq_task_lock, flags);
d691eb90 AZ	433	if (rtc->irq_task != NULL && task == NULL)
d691eb90 AZ	434	err = -EBUSY;
0c86edc0	435	if (rtc->irq_task != task)
d691eb90	436	err = -EACCES;
0c86edc0	437
6610e089 JS	438	if (enabled) {
	439	ktime_t period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
	440	hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
	441	} else {
	442	hrtimer_cancel(&rtc->pie_timer);
	443	}
	444	rtc->pie_enabled = enabled;
	445	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
0c86edc0 AZ	446
	447	return err;
	448	}
	449	EXPORT_SYMBOL_GPL(rtc_irq_set_state);
	450
97144c67 DB	451	/**
	452	* rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
	453	* @rtc: the rtc device
	454	* @task: currently registered with rtc_irq_register()
	455	* @freq: positive frequency with which task->func() will be called
	456	* Context: any
	457	*
	458	* Note that rtc_irq_set_state() is used to enable or disable the
	459	* periodic IRQs.
	460	*/
ab6a2d70	461	int rtc_irq_set_freq(struct rtc_device rtc, struct rtc_task task, int freq)
0c86edc0	462	{
56f10c63	463	int err = 0;
0c86edc0	464	unsigned long flags;
0c86edc0	465
83a06bf5 MRJ	466	if (freq <= 0)
	467	return -EINVAL;
	468
0c86edc0	469	spin_lock_irqsave(&rtc->irq_task_lock, flags);
d691eb90 AZ	470	if (rtc->irq_task != NULL && task == NULL)
d691eb90 AZ	471	err = -EBUSY;
0c86edc0	472	if (rtc->irq_task != task)
d691eb90	473	err = -EACCES;
0c86edc0	474	if (err == 0) {
6610e089 JS	475	rtc->irq_freq = freq;
	476	if (rtc->pie_enabled) {
	477	ktime_t period;
	478	hrtimer_cancel(&rtc->pie_timer);
	479	period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
	480	hrtimer_start(&rtc->pie_timer, period,
	481	HRTIMER_MODE_REL);
	482	}
0c86edc0	483	}
6610e089	484	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
0c86edc0 AZ	485	return err;
0c86edc0 AZ	486	}
2601a464	487	EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
6610e089 JS	488
6610e089 JS	489	/**
96c8f06a	490	* rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
6610e089 JS	491	* @rtc rtc device
	492	* @timer timer being added.
	493	*
	494	* Enqueues a timer onto the rtc devices timerqueue and sets
	495	* the next alarm event appropriately.
	496	*
aa0be0f4 JS	497	* Sets the enabled bit on the added timer.
aa0be0f4 JS	498	*
6610e089 JS	499	* Must hold ops_lock for proper serialization of timerqueue
6610e089 JS	500	*/
aa0be0f4	501	static int rtc_timer_enqueue(struct rtc_device rtc, struct rtc_timer timer)
6610e089	502	{
aa0be0f4	503	timer->enabled = 1;
6610e089 JS	504	timerqueue_add(&rtc->timerqueue, &timer->node);
	505	if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
	506	struct rtc_wkalrm alarm;
	507	int err;
	508	alarm.time = rtc_ktime_to_tm(timer->node.expires);
	509	alarm.enabled = 1;
	510	err = __rtc_set_alarm(rtc, &alarm);
	511	if (err == -ETIME)
	512	schedule_work(&rtc->irqwork);
aa0be0f4 JS	513	else if (err) {
	514	timerqueue_del(&rtc->timerqueue, &timer->node);
	515	timer->enabled = 0;
	516	return err;
	517	}
6610e089	518	}
aa0be0f4	519	return 0;
6610e089 JS	520	}
	521
	522	/**
96c8f06a	523	* rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
6610e089 JS	524	* @rtc rtc device
	525	* @timer timer being removed.
	526	*
	527	* Removes a timer onto the rtc devices timerqueue and sets
	528	* the next alarm event appropriately.
	529	*
aa0be0f4 JS	530	* Clears the enabled bit on the removed timer.
aa0be0f4 JS	531	*
6610e089 JS	532	* Must hold ops_lock for proper serialization of timerqueue
6610e089 JS	533	*/
aa0be0f4	534	static void rtc_timer_remove(struct rtc_device rtc, struct rtc_timer timer)
6610e089 JS	535	{
	536	struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
	537	timerqueue_del(&rtc->timerqueue, &timer->node);
aa0be0f4	538	timer->enabled = 0;
6610e089 JS	539	if (next == &timer->node) {
	540	struct rtc_wkalrm alarm;
	541	int err;
	542	next = timerqueue_getnext(&rtc->timerqueue);
	543	if (!next)
	544	return;
	545	alarm.time = rtc_ktime_to_tm(next->expires);
	546	alarm.enabled = 1;
	547	err = __rtc_set_alarm(rtc, &alarm);
	548	if (err == -ETIME)
	549	schedule_work(&rtc->irqwork);
	550	}
	551	}
	552
	553	/**
96c8f06a	554	* rtc_timer_do_work - Expires rtc timers
6610e089 JS	555	* @rtc rtc device
	556	* @timer timer being removed.
	557	*
	558	* Expires rtc timers. Reprograms next alarm event if needed.
	559	* Called via worktask.
	560	*
	561	* Serializes access to timerqueue via ops_lock mutex
	562	*/
96c8f06a	563	void rtc_timer_do_work(struct work_struct *work)
6610e089 JS	564	{
	565	struct rtc_timer *timer;
	566	struct timerqueue_node *next;
	567	ktime_t now;
	568	struct rtc_time tm;
	569
	570	struct rtc_device *rtc =
	571	container_of(work, struct rtc_device, irqwork);
	572
	573	mutex_lock(&rtc->ops_lock);
	574	again:
	575	__rtc_read_time(rtc, &tm);
	576	now = rtc_tm_to_ktime(tm);
	577	while ((next = timerqueue_getnext(&rtc->timerqueue))) {
	578	if (next->expires.tv64 > now.tv64)
	579	break;
	580
	581	/* expire timer */
	582	timer = container_of(next, struct rtc_timer, node);
	583	timerqueue_del(&rtc->timerqueue, &timer->node);
	584	timer->enabled = 0;
	585	if (timer->task.func)
	586	timer->task.func(timer->task.private_data);
	587
	588	/* Re-add/fwd periodic timers */
	589	if (ktime_to_ns(timer->period)) {
	590	timer->node.expires = ktime_add(timer->node.expires,
	591	timer->period);
	592	timer->enabled = 1;
	593	timerqueue_add(&rtc->timerqueue, &timer->node);
	594	}
	595	}
	596
	597	/* Set next alarm */
	598	if (next) {
	599	struct rtc_wkalrm alarm;
	600	int err;
	601	alarm.time = rtc_ktime_to_tm(next->expires);
	602	alarm.enabled = 1;
	603	err = __rtc_set_alarm(rtc, &alarm);
	604	if (err == -ETIME)
	605	goto again;
	606	}
	607
	608	mutex_unlock(&rtc->ops_lock);
	609	}
	610
	611
96c8f06a	612	/* rtc_timer_init - Initializes an rtc_timer
6610e089 JS	613	* @timer: timer to be intiialized
	614	* @f: function pointer to be called when timer fires
	615	* @data: private data passed to function pointer
	616	*
	617	* Kernel interface to initializing an rtc_timer.
	618	*/
96c8f06a	619	void rtc_timer_init(struct rtc_timer timer, void (f)(void* p), void* data)
6610e089 JS	620	{
	621	timerqueue_init(&timer->node);
	622	timer->enabled = 0;
	623	timer->task.func = f;
	624	timer->task.private_data = data;
	625	}
	626
96c8f06a	627	/* rtc_timer_start - Sets an rtc_timer to fire in the future
6610e089 JS	628	* @ rtc: rtc device to be used
	629	* @ timer: timer being set
	630	* @ expires: time at which to expire the timer
	631	* @ period: period that the timer will recur
	632	*
	633	* Kernel interface to set an rtc_timer
	634	*/
96c8f06a	635	int rtc_timer_start(struct rtc_device rtc, struct rtc_timer timer,
6610e089 JS	636	ktime_t expires, ktime_t period)
	637	{
	638	int ret = 0;
	639	mutex_lock(&rtc->ops_lock);
	640	if (timer->enabled)
96c8f06a	641	rtc_timer_remove(rtc, timer);
6610e089 JS	642
	643	timer->node.expires = expires;
	644	timer->period = period;
	645
aa0be0f4	646	ret = rtc_timer_enqueue(rtc, timer);
6610e089 JS	647
	648	mutex_unlock(&rtc->ops_lock);
	649	return ret;
	650	}
	651
96c8f06a	652	/* rtc_timer_cancel - Stops an rtc_timer
6610e089 JS	653	* @ rtc: rtc device to be used
	654	* @ timer: timer being set
	655	*
	656	* Kernel interface to cancel an rtc_timer
	657	*/
96c8f06a	658	int rtc_timer_cancel(struct rtc_device rtc, struct rtc_timer timer)
6610e089 JS	659	{
	660	int ret = 0;
	661	mutex_lock(&rtc->ops_lock);
	662	if (timer->enabled)
96c8f06a	663	rtc_timer_remove(rtc, timer);
6610e089 JS	664	mutex_unlock(&rtc->ops_lock);
	665	return ret;
	666	}
	667
	668