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linux-next/include/linux/alarmtimer.h
John Stultz 9082c465a5 alarmtimers: Add try_to_cancel functionality
There's a number of edge cases when cancelling a alarm, so
to be sure we accurately do so, introduce try_to_cancel, which
returns proper failure errors if it cannot. Also modify cancel
to spin until the alarm is properly disabled.

CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-08-10 14:55:29 -07:00

80 lines
1.9 KiB
C

#ifndef _LINUX_ALARMTIMER_H
#define _LINUX_ALARMTIMER_H
#include <linux/time.h>
#include <linux/hrtimer.h>
#include <linux/timerqueue.h>
#include <linux/rtc.h>
enum alarmtimer_type {
ALARM_REALTIME,
ALARM_BOOTTIME,
ALARM_NUMTYPE,
};
enum alarmtimer_restart {
ALARMTIMER_NORESTART,
ALARMTIMER_RESTART,
};
#define ALARMTIMER_STATE_INACTIVE 0x00
#define ALARMTIMER_STATE_ENQUEUED 0x01
#define ALARMTIMER_STATE_CALLBACK 0x02
/**
* struct alarm - Alarm timer structure
* @node: timerqueue node for adding to the event list this value
* also includes the expiration time.
* @period: Period for recuring alarms
* @function: Function pointer to be executed when the timer fires.
* @type: Alarm type (BOOTTIME/REALTIME)
* @enabled: Flag that represents if the alarm is set to fire or not
* @data: Internal data value.
*/
struct alarm {
struct timerqueue_node node;
enum alarmtimer_restart (*function)(struct alarm *, ktime_t now);
enum alarmtimer_type type;
int state;
void *data;
};
void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
enum alarmtimer_restart (*function)(struct alarm *, ktime_t));
void alarm_start(struct alarm *alarm, ktime_t start);
int alarm_try_to_cancel(struct alarm *alarm);
int alarm_cancel(struct alarm *alarm);
u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval);
/*
* A alarmtimer is active, when it is enqueued into timerqueue or the
* callback function is running.
*/
static inline int alarmtimer_active(const struct alarm *timer)
{
return timer->state != ALARMTIMER_STATE_INACTIVE;
}
/*
* Helper function to check, whether the timer is on one of the queues
*/
static inline int alarmtimer_is_queued(struct alarm *timer)
{
return timer->state & ALARMTIMER_STATE_ENQUEUED;
}
/*
* Helper function to check, whether the timer is running the callback
* function
*/
static inline int alarmtimer_callback_running(struct alarm *timer)
{
return timer->state & ALARMTIMER_STATE_CALLBACK;
}
#endif