RTC: Rework RTC code to use timerqueue for events

#include <linux/kdev_t.h>

#include <linux/idr.h>

#include <linux/slab.h>

#include <linux/workqueue.h>

#include "rtc-core.h"

	spin_lock_init(&rtc->irq_task_lock);

	init_waitqueue_head(&rtc->irq_queue);

	/* Init timerqueue */

	timerqueue_init_head(&rtc->timerqueue);

	INIT_WORK(&rtc->irqwork, rtctimer_do_work);

	/* Init aie timer */

	rtctimer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);

	/* Init uie timer */

	rtctimer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);

	/* Init pie timer */

	hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	rtc->pie_timer.function = rtc_pie_update_irq;

	rtc->pie_enabled = 0;

	strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);

	dev_set_name(&rtc->dev, "rtc%d", id);

#include <linux/rtc.h>

#include <linux/sched.h>

#include <linux/log2.h>

#include <linux/workqueue.h>

int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)

static 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;

	if (!rtc->ops)

		err = -ENODEV;

	else if (!rtc->ops->read_time)

		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_set_mmss);

static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)

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));

		err = rtc->ops->read_alarm(rtc->dev.parent, alarm);

	}

	alarm->enabled = rtc->aie_timer.enabled;

	if (alarm->enabled)

		alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);

	mutex_unlock(&rtc->ops_lock);

	return err;

	return 0;

}

EXPORT_SYMBOL_GPL(rtc_read_alarm);

int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)

int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)

{

	struct rtc_time tm;

	long now, scheduled;

	int err;

	struct rtc_time before, now;

	int first_time = 1;

	unsigned long t_now, t_alm;

	enum { none, day, month, year } missing = none;

	unsigned days;

	/* The lower level RTC driver may return -1 in some fields,

	 * creating invalid alarm->time values, for reasons like:

	 *

	 *   - The hardware may not be capable of filling them in;

	 *     many alarms match only on time-of-day fields, not

	 *     day/month/year calendar data.

	 *

	 *   - Some hardware uses illegal values as "wildcard" match

	 *     values, which non-Linux firmware (like a BIOS) may try

	 *     to set up as e.g. "alarm 15 minutes after each hour".

	 *     Linux uses only oneshot alarms.

	 *

	 * When we see that here, we deal with it by using values from

	 * a current RTC timestamp for any missing (-1) values.  The

	 * RTC driver prevents "periodic alarm" modes.

	 *

	 * But this can be racey, because some fields of the RTC timestamp

	 * may have wrapped in the interval since we read the RTC alarm,

	 * which would lead to us inserting inconsistent values in place

	 * of the -1 fields.

	 *

	 * Reading the alarm and timestamp in the reverse sequence

	 * would have the same race condition, and not solve the issue.

	 *

	 * So, we must first read the RTC timestamp,

	 * then read the RTC alarm value,

	 * and then read a second RTC timestamp.

	 *

	 * If any fields of the second timestamp have changed

	 * when compared with the first timestamp, then we know

	 * our timestamp may be inconsistent with that used by

	 * the low-level rtc_read_alarm_internal() function.

	 *

	 * So, when the two timestamps disagree, we just loop and do

	 * the process again to get a fully consistent set of values.

	 *

	 * This could all instead be done in the lower level driver,

	 * but since more than one lower level RTC implementation needs it,

	 * then it's probably best best to do it here instead of there..

	 */

	/* Get the "before" timestamp */

	err = rtc_read_time(rtc, &before);

	if (err < 0)

		return err;

	do {

		if (!first_time)

			memcpy(&before, &now, sizeof(struct rtc_time));

		first_time = 0;

		/* get the RTC alarm values, which may be incomplete */

		err = rtc_read_alarm_internal(rtc, alarm);

	err = rtc_valid_tm(&alarm->time);

	if (err)

		return err;

		if (!alarm->enabled)

			return 0;

		/* full-function RTCs won't have such missing fields */

		if (rtc_valid_tm(&alarm->time) == 0)

			return 0;

		/* get the "after" timestamp, to detect wrapped fields */

		err = rtc_read_time(rtc, &now);

		if (err < 0)

			return err;

	rtc_tm_to_time(&alarm->time, &scheduled);

		/* note that tm_sec is a "don't care" value here: */

	} while (   before.tm_min   != now.tm_min

		 || before.tm_hour  != now.tm_hour

		 || before.tm_mon   != now.tm_mon

		 || before.tm_year  != now.tm_year);

	/* Fill in the missing alarm fields using the timestamp; we

	 * know there's at least one since alarm->time is invalid.

	 */

	if (alarm->time.tm_sec == -1)

		alarm->time.tm_sec = now.tm_sec;

	if (alarm->time.tm_min == -1)

		alarm->time.tm_min = now.tm_min;

	if (alarm->time.tm_hour == -1)

		alarm->time.tm_hour = now.tm_hour;

	/* For simplicity, only support date rollover for now */

	if (alarm->time.tm_mday == -1) {

		alarm->time.tm_mday = now.tm_mday;

		missing = day;

	}

	if (alarm->time.tm_mon == -1) {

		alarm->time.tm_mon = now.tm_mon;

		if (missing == none)

			missing = month;

	}

	if (alarm->time.tm_year == -1) {

		alarm->time.tm_year = now.tm_year;

		if (missing == none)

			missing = year;

	}

	/* with luck, no rollover is needed */

	rtc_tm_to_time(&now, &t_now);

	rtc_tm_to_time(&alarm->time, &t_alm);

	if (t_now < t_alm)

		goto done;

	switch (missing) {

	/* 24 hour rollover ... if it's now 10am Monday, an alarm that

	 * that will trigger at 5am will do so at 5am Tuesday, which

	 * could also be in the next month or year.  This is a common

	 * case, especially for PCs.

	/* 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.

	 */

	case day:

		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");

		t_alm += 24 * 60 * 60;

		rtc_time_to_tm(t_alm, &alarm->time);

		break;

	/* Month rollover ... if it's the 31th, an alarm on the 3rd will

	 * be next month.  An alarm matching on the 30th, 29th, or 28th

	 * may end up in the month after that!  Many newer PCs support

	 * this type of alarm.

	 */

	case month:

		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");

		do {

			if (alarm->time.tm_mon < 11)

				alarm->time.tm_mon++;

			else {

				alarm->time.tm_mon = 0;

				alarm->time.tm_year++;

			}

			days = rtc_month_days(alarm->time.tm_mon,

					alarm->time.tm_year);

		} while (days < alarm->time.tm_mday);

		break;

	/* Year rollover ... easy except for leap years! */

	case year:

		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");

		do {

			alarm->time.tm_year++;

		} while (rtc_valid_tm(&alarm->time) != 0);

		break;

	default:

		dev_warn(&rtc->dev, "alarm rollover not handled\n");

	}

	if (!rtc->ops)

		err = -ENODEV;

	else if (!rtc->ops->set_alarm)

		err = -EINVAL;

	else

		err = rtc->ops->set_alarm(rtc->dev.parent, alarm);

done:

	return 0;

	return err;

}

EXPORT_SYMBOL_GPL(rtc_read_alarm);

int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)

{

	err = mutex_lock_interruptible(&rtc->ops_lock);

	if (err)

		return err;

	if (!rtc->ops)

		err = -ENODEV;

	else if (!rtc->ops->set_alarm)

		err = -EINVAL;

	else

		err = rtc->ops->set_alarm(rtc->dev.parent, alarm);

	if (rtc->aie_timer.enabled) {

		rtctimer_remove(rtc, &rtc->aie_timer);

		rtc->aie_timer.enabled = 0;

	}

	rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);

	rtc->aie_timer.period = ktime_set(0, 0);

	if (alarm->enabled) {

		rtc->aie_timer.enabled = 1;

		rtctimer_enqueue(rtc, &rtc->aie_timer);

	}

	mutex_unlock(&rtc->ops_lock);

	return err;

	return 0;

}

EXPORT_SYMBOL_GPL(rtc_set_alarm);

	if (err)

		return err;

	if (rtc->aie_timer.enabled != enabled) {

		if (enabled) {

			rtc->aie_timer.enabled = 1;

			rtctimer_enqueue(rtc, &rtc->aie_timer);

		} else {

			rtctimer_remove(rtc, &rtc->aie_timer);

			rtc->aie_timer.enabled = 0;

		}

	}

	if (!rtc->ops)

		err = -ENODEV;

	else if (!rtc->ops->alarm_irq_enable)

	if (err)

		return err;

#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

	if (enabled == 0 && rtc->uie_irq_active) {

		mutex_unlock(&rtc->ops_lock);

		return rtc_dev_update_irq_enable_emul(rtc, enabled);

	/* 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);

		rtc->uie_rtctimer.enabled = 1;

		rtctimer_enqueue(rtc, &rtc->uie_rtctimer);

	} else {

		rtctimer_remove(rtc, &rtc->uie_rtctimer);

		rtc->uie_rtctimer.enabled = 0;

	}

#endif

	if (!rtc->ops)

		err = -ENODEV;

	else if (!rtc->ops->update_irq_enable)

		err = -EINVAL;

	else

		err = rtc->ops->update_irq_enable(rtc->dev.parent, enabled);

out:

	mutex_unlock(&rtc->ops_lock);

#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

	/*

	 * Enable emulation if the driver did not provide

	 * the update_irq_enable function pointer or if returned

	 * -EINVAL to signal that it has been configured without

	 * interrupts or that are not available at the moment.

	 */

	if (err == -EINVAL)

		err = rtc_dev_update_irq_enable_emul(rtc, enabled);

#endif

	return err;

}

EXPORT_SYMBOL_GPL(rtc_update_irq_enable);

/**

 * rtc_update_irq - report RTC periodic, alarm, and/or update irqs

 * @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

 * 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.

 */

void rtc_update_irq(struct rtc_device *rtc,

		unsigned long num, unsigned long events)

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)) | events;

	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);

	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)

	int err = 0;

	unsigned long flags;

	if (rtc->ops->irq_set_state == NULL)

		return -ENXIO;

	spin_lock_irqsave(&rtc->irq_task_lock, flags);

	if (rtc->irq_task != NULL && task == NULL)

		err = -EBUSY;

	if (rtc->irq_task != task)

		err = -EACCES;

	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);

	if (err == 0)

		err = rtc->ops->irq_set_state(rtc->dev.parent, enabled);

	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;

}

	int err = 0;

	unsigned long flags;

	if (rtc->ops->irq_set_freq == NULL)

		return -ENXIO;

	spin_lock_irqsave(&rtc->irq_task_lock, flags);

	if (rtc->irq_task != NULL && task == NULL)

		err = -EBUSY;

	if (rtc->irq_task != task)

		err = -EACCES;

	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);

	if (err == 0) {

		err = rtc->ops->irq_set_freq(rtc->dev.parent, freq);

		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);

/**

 * rtctimer_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.

 *

 * Must hold ops_lock for proper serialization of timerqueue

 */

void rtctimer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)

{

	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);

	}

}

/**

 * rtctimer_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.

 *

 * Must hold ops_lock for proper serialization of timerqueue

 */

void rtctimer_remove(struct rtc_device *rtc, struct rtc_timer *timer)

{

	struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);

	timerqueue_del(&rtc->timerqueue, &timer->node);

	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);

	}

}

/**

 * rtctimer_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 rtctimer_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);

}

/* rtctimer_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 rtctimer_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;

}

/* rtctimer_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 rtctimer_start(struct rtc_device *rtc, struct rtc_timer* timer,

			ktime_t expires, ktime_t period)