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linux/drivers/rtc/interface.c

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/*
* 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/module.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);
/* A timer might have just expired */
schedule_work(&rtc->irqwork);
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);
/* A timer might have just expired */
schedule_work(&rtc->irqwork);
return err;
}
EXPORT_SYMBOL_GPL(rtc_set_mmss);
static int rtc_read_alarm_internal(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);
}
mutex_unlock(&rtc->ops_lock);
return err;
}
int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
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);
if (err)
return err;
/* 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;
/* 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 > 31) {
alarm->time.tm_mday = now.tm_mday;
missing = day;
}
if ((unsigned)alarm->time.tm_mon >= 12) {
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.
*/
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");
}
done:
return 0;
}
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);
static 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);
/* Called once per device from rtc_device_register */
int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
int err;
struct rtc_time now;
err = rtc_valid_tm(&alarm->time);
if (err != 0)
return err;
err = rtc_read_time(rtc, &now);
if (err)
return err;
err = mutex_lock_interruptible(&rtc->ops_lock);
if (err)
return err;
rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
rtc->aie_timer.period = ktime_set(0, 0);
/* Alarm has to be enabled & in the futrure for us to enqueue it */
if (alarm->enabled && (rtc_tm_to_ktime(now).tv64 <
rtc->aie_timer.node.expires.tv64)) {
rtc->aie_timer.enabled = 1;
timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
}
mutex_unlock(&rtc->ops_lock);
return err;
}
EXPORT_SYMBOL_GPL(rtc_initialize_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;
#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, 0);
}
#endif
/* make sure we're changing state */
if (rtc->uie_rtctimer.enabled == enabled)
goto out;
if (rtc->uie_unsupported) {
err = -EINVAL;
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);
#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_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 occurred (or been emulated).
*
* Triggers the registered irq_task function callback.
*/
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);
static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
{
/*
* We always cancel the timer here first, because otherwise
* we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
* when we manage to start the timer before the callback
* returns HRTIMER_RESTART.
*
* We cannot use hrtimer_cancel() here as a running callback
* could be blocked on rtc->irq_task_lock and hrtimer_cancel()
* would spin forever.
*/
if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
return -1;
if (enabled) {
ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq);
hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
}
return 0;
}
/**
* 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;
retry:
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) {
if (rtc_update_hrtimer(rtc, enabled) < 0) {
spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
cpu_relax();
goto retry;
}
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 || freq > RTC_MAX_FREQ)
return -EINVAL;
retry:
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) {
rtc->irq_freq = freq;
if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
cpu_relax();
goto retry;
}
}
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;
}
static void rtc_alarm_disable(struct rtc_device *rtc)
{
if (!rtc->ops || !rtc->ops->alarm_irq_enable)
return;
rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
}
/**
* 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) {
rtc_alarm_disable(rtc);
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;
} else
rtc_alarm_disable(rtc);
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;
}
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