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

// SPDX-License-Identifier: GPL-2.0
/*
 * kernel/power/autosleep.c
 *
 * Opportunistic sleep support.
 *
 * Copyright (C) 2012 Rafael J. Wysocki <[email protected]>
 */

#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 occurred 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(NULL, "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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
7483b4a4 RW	2	/*
	3	* kernel/power/autosleep.c
	4	*
	5	* Opportunistic sleep support.
	6	*
	7	* Copyright (C) 2012 Rafael J. Wysocki <[email protected]>
	8	*/
	9
	10	#include <linux/device.h>
	11	#include <linux/mutex.h>
	12	#include <linux/pm_wakeup.h>
	13
	14	#include "power.h"
	15
	16	static suspend_state_t autosleep_state;
	17	static struct workqueue_struct *autosleep_wq;
	18	/*
	19	* Note: it is only safe to mutex_lock(&autosleep_lock) if a wakeup_source
	20	* is active, otherwise a deadlock with try_to_suspend() is possible.
	21	* Alternatively mutex_lock_interruptible() can be used. This will then fail
	22	* if an auto_sleep cycle tries to freeze processes.
	23	*/
	24	static DEFINE_MUTEX(autosleep_lock);
	25	static struct wakeup_source *autosleep_ws;
	26
	27	static void try_to_suspend(struct work_struct *work)
	28	{
	29	unsigned int initial_count, final_count;
	30
	31	if (!pm_get_wakeup_count(&initial_count, true))
	32	goto out;
	33
	34	mutex_lock(&autosleep_lock);
	35
e5248a11 LS	36	if (!pm_save_wakeup_count(initial_count) \|\|
e5248a11 LS	37	system_state != SYSTEM_RUNNING) {
7483b4a4 RW	38	mutex_unlock(&autosleep_lock);
	39	goto out;
	40	}
	41
	42	if (autosleep_state == PM_SUSPEND_ON) {
	43	mutex_unlock(&autosleep_lock);
	44	return;
	45	}
	46	if (autosleep_state >= PM_SUSPEND_MAX)
	47	hibernate();
	48	else
	49	pm_suspend(autosleep_state);
	50
	51	mutex_unlock(&autosleep_lock);
	52
	53	if (!pm_get_wakeup_count(&final_count, false))
	54	goto out;
	55
	56	/*
e4b2897a	57	* If the wakeup occurred for an unknown reason, wait to prevent the
7483b4a4 RW	58	* system from trying to suspend and waking up in a tight loop.
	59	*/
	60	if (final_count == initial_count)
	61	schedule_timeout_uninterruptible(HZ / 2);
	62
	63	out:
	64	queue_up_suspend_work();
	65	}
	66
	67	static DECLARE_WORK(suspend_work, try_to_suspend);
	68
	69	void queue_up_suspend_work(void)
	70	{
ed1ac6e9	71	if (autosleep_state > PM_SUSPEND_ON)
7483b4a4 RW	72	queue_work(autosleep_wq, &suspend_work);
	73	}
	74
	75	suspend_state_t pm_autosleep_state(void)
	76	{
	77	return autosleep_state;
	78	}
	79
	80	int pm_autosleep_lock(void)
	81	{
	82	return mutex_lock_interruptible(&autosleep_lock);
	83	}
	84
	85	void pm_autosleep_unlock(void)
	86	{
	87	mutex_unlock(&autosleep_lock);
	88	}
	89
	90	int pm_autosleep_set_state(suspend_state_t state)
	91	{
	92
	93	#ifndef CONFIG_HIBERNATION
	94	if (state >= PM_SUSPEND_MAX)
	95	return -EINVAL;
	96	#endif
	97
	98	__pm_stay_awake(autosleep_ws);
	99
	100	mutex_lock(&autosleep_lock);
	101
	102	autosleep_state = state;
	103
	104	__pm_relax(autosleep_ws);
	105
55850945 RW	106	if (state > PM_SUSPEND_ON) {
55850945 RW	107	pm_wakep_autosleep_enabled(true);
7483b4a4	108	queue_up_suspend_work();
55850945 RW	109	} else {
	110	pm_wakep_autosleep_enabled(false);
	111	}
7483b4a4 RW	112
	113	mutex_unlock(&autosleep_lock);
	114	return 0;
	115	}
	116
	117	int __init pm_autosleep_init(void)
	118	{
c8377adf	119	autosleep_ws = wakeup_source_register(NULL, "autosleep");
7483b4a4 RW	120	if (!autosleep_ws)
	121	return -ENOMEM;
	122
	123	autosleep_wq = alloc_ordered_workqueue("autosleep", 0);
	124	if (autosleep_wq)
	125	return 0;
	126
	127	wakeup_source_unregister(autosleep_ws);
	128	return -ENOMEM;
	129	}