// SPDX-License-Identifier: GPL-2.0/* * 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 "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;}