[deliverable/linux.git] / kernel / power / autosleep.c

/*
 * 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) ||
		system_state != SYSTEM_RUNNING) {
		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 (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;
}
Commit	Line	Data
7483b4a4 RW	1	/*
	2	* kernel/power/autosleep.c
	3	*
	4	* Opportunistic sleep support.
	5	*
	6	* Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
	7	*/
	8
	9	#include <linux/device.h>
	10	#include <linux/mutex.h>
	11	#include <linux/pm_wakeup.h>
	12
	13	#include "power.h"
	14
	15	static suspend_state_t autosleep_state;
	16	static struct workqueue_struct *autosleep_wq;
	17	/*
	18	* Note: it is only safe to mutex_lock(&autosleep_lock) if a wakeup_source
	19	* is active, otherwise a deadlock with try_to_suspend() is possible.
	20	* Alternatively mutex_lock_interruptible() can be used. This will then fail
	21	* if an auto_sleep cycle tries to freeze processes.
	22	*/
	23	static DEFINE_MUTEX(autosleep_lock);
	24	static struct wakeup_source *autosleep_ws;
	25
	26	static void try_to_suspend(struct work_struct *work)
	27	{
	28	unsigned int initial_count, final_count;
	29
	30	if (!pm_get_wakeup_count(&initial_count, true))
	31	goto out;
	32
	33	mutex_lock(&autosleep_lock);
	34
e5248a11 LS	35	if (!pm_save_wakeup_count(initial_count) \|\|
e5248a11 LS	36	system_state != SYSTEM_RUNNING) {
7483b4a4 RW	37	mutex_unlock(&autosleep_lock);
	38	goto out;
	39	}
	40
	41	if (autosleep_state == PM_SUSPEND_ON) {
	42	mutex_unlock(&autosleep_lock);
	43	return;
	44	}
	45	if (autosleep_state >= PM_SUSPEND_MAX)
	46	hibernate();
	47	else
	48	pm_suspend(autosleep_state);
	49
	50	mutex_unlock(&autosleep_lock);
	51
	52	if (!pm_get_wakeup_count(&final_count, false))
	53	goto out;
	54
	55	/*
	56	* If the wakeup occured for an unknown reason, wait to prevent the
	57	* system from trying to suspend and waking up in a tight loop.
	58	*/
	59	if (final_count == initial_count)
	60	schedule_timeout_uninterruptible(HZ / 2);
	61
	62	out:
	63	queue_up_suspend_work();
	64	}
	65
	66	static DECLARE_WORK(suspend_work, try_to_suspend);
	67
	68	void queue_up_suspend_work(void)
	69	{
ed1ac6e9	70	if (autosleep_state > PM_SUSPEND_ON)
7483b4a4 RW	71	queue_work(autosleep_wq, &suspend_work);
	72	}
	73
	74	suspend_state_t pm_autosleep_state(void)
	75	{
	76	return autosleep_state;
	77	}
	78
	79	int pm_autosleep_lock(void)
	80	{
	81	return mutex_lock_interruptible(&autosleep_lock);
	82	}
	83
	84	void pm_autosleep_unlock(void)
	85	{
	86	mutex_unlock(&autosleep_lock);
	87	}
	88
	89	int pm_autosleep_set_state(suspend_state_t state)
	90	{
	91
	92	#ifndef CONFIG_HIBERNATION
	93	if (state >= PM_SUSPEND_MAX)
	94	return -EINVAL;
	95	#endif
	96
	97	__pm_stay_awake(autosleep_ws);
	98
	99	mutex_lock(&autosleep_lock);
	100
	101	autosleep_state = state;
	102
	103	__pm_relax(autosleep_ws);
	104
55850945 RW	105	if (state > PM_SUSPEND_ON) {
55850945 RW	106	pm_wakep_autosleep_enabled(true);
7483b4a4	107	queue_up_suspend_work();
55850945 RW	108	} else {
	109	pm_wakep_autosleep_enabled(false);
	110	}
7483b4a4 RW	111
	112	mutex_unlock(&autosleep_lock);
	113	return 0;
	114	}
	115
	116	int __init pm_autosleep_init(void)
	117	{
	118	autosleep_ws = wakeup_source_register("autosleep");
	119	if (!autosleep_ws)
	120	return -ENOMEM;
	121
	122	autosleep_wq = alloc_ordered_workqueue("autosleep", 0);
	123	if (autosleep_wq)
	124	return 0;
	125
	126	wakeup_source_unregister(autosleep_ws);
	127	return -ENOMEM;
	128	}