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128 lines · 2.6 KiB

1// SPDX-License-Identifier: GPL-2.0
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
13#include "power.h"
14
15static suspend_state_t autosleep_state;
16static 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 */
23static DEFINE_MUTEX(autosleep_lock);
24static struct wakeup_source *autosleep_ws;
25
26static 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
35 if (!pm_save_wakeup_count(initial_count) ||
36 system_state != SYSTEM_RUNNING) {
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 occurred 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
66static DECLARE_WORK(suspend_work, try_to_suspend);
67
68void queue_up_suspend_work(void)
69{
70 if (autosleep_state > PM_SUSPEND_ON)
71 queue_work(autosleep_wq, &suspend_work);
72}
73
74suspend_state_t pm_autosleep_state(void)
75{
76 return autosleep_state;
77}
78
79int pm_autosleep_lock(void)
80{
81 return mutex_lock_interruptible(&autosleep_lock);
82}
83
84void pm_autosleep_unlock(void)
85{
86 mutex_unlock(&autosleep_lock);
87}
88
89int 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
105 if (state > PM_SUSPEND_ON) {
106 pm_wakep_autosleep_enabled(true);
107 queue_up_suspend_work();
108 } else {
109 pm_wakep_autosleep_enabled(false);
110 }
111
112 mutex_unlock(&autosleep_lock);
113 return 0;
114}
115
116int __init pm_autosleep_init(void)
117{
118 autosleep_ws = wakeup_source_register(NULL, "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}