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Merge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[karo-tx-linux.git] / kernel / power / autosleep.c
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
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 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 {
70         if (autosleep_state > PM_SUSPEND_ON)
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
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
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 }