Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / kernel / power / autosleep.c
blob41e83a779e19992f0097c92622332a05b1c4043e
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * kernel/power/autosleep.c
5 * Opportunistic sleep support.
7 * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
8 */
10 #include <linux/device.h>
11 #include <linux/mutex.h>
12 #include <linux/pm_wakeup.h>
14 #include "power.h"
16 static suspend_state_t autosleep_state;
17 static struct workqueue_struct *autosleep_wq;
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.
24 static DEFINE_MUTEX(autosleep_lock);
25 static struct wakeup_source *autosleep_ws;
27 static void try_to_suspend(struct work_struct *work)
29 unsigned int initial_count, final_count;
31 if (!pm_get_wakeup_count(&initial_count, true))
32 goto out;
34 mutex_lock(&autosleep_lock);
36 if (!pm_save_wakeup_count(initial_count) ||
37 system_state != SYSTEM_RUNNING) {
38 mutex_unlock(&autosleep_lock);
39 goto out;
42 if (autosleep_state == PM_SUSPEND_ON) {
43 mutex_unlock(&autosleep_lock);
44 return;
46 if (autosleep_state >= PM_SUSPEND_MAX)
47 hibernate();
48 else
49 pm_suspend(autosleep_state);
51 mutex_unlock(&autosleep_lock);
53 if (!pm_get_wakeup_count(&final_count, false))
54 goto out;
57 * If the wakeup occured for an unknown reason, wait to prevent the
58 * system from trying to suspend and waking up in a tight loop.
60 if (final_count == initial_count)
61 schedule_timeout_uninterruptible(HZ / 2);
63 out:
64 queue_up_suspend_work();
67 static DECLARE_WORK(suspend_work, try_to_suspend);
69 void queue_up_suspend_work(void)
71 if (autosleep_state > PM_SUSPEND_ON)
72 queue_work(autosleep_wq, &suspend_work);
75 suspend_state_t pm_autosleep_state(void)
77 return autosleep_state;
80 int pm_autosleep_lock(void)
82 return mutex_lock_interruptible(&autosleep_lock);
85 void pm_autosleep_unlock(void)
87 mutex_unlock(&autosleep_lock);
90 int pm_autosleep_set_state(suspend_state_t state)
93 #ifndef CONFIG_HIBERNATION
94 if (state >= PM_SUSPEND_MAX)
95 return -EINVAL;
96 #endif
98 __pm_stay_awake(autosleep_ws);
100 mutex_lock(&autosleep_lock);
102 autosleep_state = state;
104 __pm_relax(autosleep_ws);
106 if (state > PM_SUSPEND_ON) {
107 pm_wakep_autosleep_enabled(true);
108 queue_up_suspend_work();
109 } else {
110 pm_wakep_autosleep_enabled(false);
113 mutex_unlock(&autosleep_lock);
114 return 0;
117 int __init pm_autosleep_init(void)
119 autosleep_ws = wakeup_source_register("autosleep");
120 if (!autosleep_ws)
121 return -ENOMEM;
123 autosleep_wq = alloc_ordered_workqueue("autosleep", 0);
124 if (autosleep_wq)
125 return 0;
127 wakeup_source_unregister(autosleep_ws);
128 return -ENOMEM;