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/*
* kernel/power/autosleep.c
*
* Opportunistic sleep support.
*
* Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
*/
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/pm_wakeup.h>
#include "power.h"
static suspend_state_t autosleep_state;
static struct workqueue_struct *autosleep_wq;
/*
* Note: it is only safe to mutex_lock(&autosleep_lock) if a wakeup_source
* is active, otherwise a deadlock with try_to_suspend() is possible.
* Alternatively mutex_lock_interruptible() can be used. This will then fail
* if an auto_sleep cycle tries to freeze processes.
*/
static DEFINE_MUTEX(autosleep_lock);
static struct wakeup_source *autosleep_ws;
static void try_to_suspend(struct work_struct *work)
{
unsigned int initial_count, final_count;
if (!pm_get_wakeup_count(&initial_count, true))
goto out;
mutex_lock(&autosleep_lock);
if (!pm_save_wakeup_count(initial_count)) {
mutex_unlock(&autosleep_lock);
goto out;
}
if (autosleep_state == PM_SUSPEND_ON) {
mutex_unlock(&autosleep_lock);
return;
}
if (autosleep_state >= PM_SUSPEND_MAX)
hibernate();
else
pm_suspend(autosleep_state);
mutex_unlock(&autosleep_lock);
if (!pm_get_wakeup_count(&final_count, false))
goto out;
/*
* If the wakeup occured for an unknown reason, wait to prevent the
* system from trying to suspend and waking up in a tight loop.
*/
if (final_count == initial_count)
schedule_timeout_uninterruptible(HZ / 2);
out:
queue_up_suspend_work();
}
static DECLARE_WORK(suspend_work, try_to_suspend);
void queue_up_suspend_work(void)
{
if (!work_pending(&suspend_work) && autosleep_state > PM_SUSPEND_ON)
queue_work(autosleep_wq, &suspend_work);
}
suspend_state_t pm_autosleep_state(void)
{
return autosleep_state;
}
int pm_autosleep_lock(void)
{
return mutex_lock_interruptible(&autosleep_lock);
}
void pm_autosleep_unlock(void)
{
mutex_unlock(&autosleep_lock);
}
int pm_autosleep_set_state(suspend_state_t state)
{
#ifndef CONFIG_HIBERNATION
if (state >= PM_SUSPEND_MAX)
return -EINVAL;
#endif
__pm_stay_awake(autosleep_ws);
mutex_lock(&autosleep_lock);
autosleep_state = state;
__pm_relax(autosleep_ws);
if (state > PM_SUSPEND_ON) {
pm_wakep_autosleep_enabled(true);
queue_up_suspend_work();
} else {
pm_wakep_autosleep_enabled(false);
}
mutex_unlock(&autosleep_lock);
return 0;
}
int __init pm_autosleep_init(void)
{
autosleep_ws = wakeup_source_register("autosleep");
if (!autosleep_ws)
return -ENOMEM;
autosleep_wq = alloc_ordered_workqueue("autosleep", 0);
if (autosleep_wq)
return 0;
wakeup_source_unregister(autosleep_ws);
return -ENOMEM;
}
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