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 <rjw@sisk.pl> 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 36 if (!pm_save_wakeup_count(initial_count) || 37 system_state != SYSTEM_RUNNING) { 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 /* 57 * If the wakeup occurred for an unknown reason, wait to prevent the 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 { 71 if (autosleep_state > PM_SUSPEND_ON) 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); 105 106 if (state > PM_SUSPEND_ON) { 107 pm_wakep_autosleep_enabled(true); 108 queue_up_suspend_work(); 109 } else { 110 pm_wakep_autosleep_enabled(false); 111 } 112 113 mutex_unlock(&autosleep_lock); 114 return 0; 115 } 116 117 int __init pm_autosleep_init(void) 118 { 119 autosleep_ws = wakeup_source_register(NULL, "autosleep"); 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 } 130