1 // SPDX-License-Identifier: GPL-2.0
3 * kernel/power/wakelock.c
5 * User space wakeup sources support.
7 * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
9 * This code is based on the analogous interface allowing user space to
10 * manipulate wakelocks on Android.
13 #include <linux/capability.h>
14 #include <linux/ctype.h>
15 #include <linux/device.h>
16 #include <linux/err.h>
17 #include <linux/hrtimer.h>
18 #include <linux/list.h>
19 #include <linux/rbtree.h>
20 #include <linux/slab.h>
21 #include <linux/workqueue.h>
25 static DEFINE_MUTEX(wakelocks_lock);
30 struct wakeup_source ws;
31 #ifdef CONFIG_PM_WAKELOCKS_GC
36 static struct rb_root wakelocks_tree = RB_ROOT;
38 ssize_t pm_show_wakelocks(char *buf, bool show_active)
44 mutex_lock(&wakelocks_lock);
46 for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
47 wl = rb_entry(node, struct wakelock, node);
48 if (wl->ws.active == show_active)
49 len += sysfs_emit_at(buf, len, "%s ", wl->name);
51 len += sysfs_emit_at(buf, len, "\n");
53 mutex_unlock(&wakelocks_lock);
57 #if CONFIG_PM_WAKELOCKS_LIMIT > 0
58 static unsigned int number_of_wakelocks;
60 static inline bool wakelocks_limit_exceeded(void)
62 return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
65 static inline void increment_wakelocks_number(void)
67 number_of_wakelocks++;
70 static inline void decrement_wakelocks_number(void)
72 number_of_wakelocks--;
74 #else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
75 static inline bool wakelocks_limit_exceeded(void) { return false; }
76 static inline void increment_wakelocks_number(void) {}
77 static inline void decrement_wakelocks_number(void) {}
78 #endif /* CONFIG_PM_WAKELOCKS_LIMIT */
80 #ifdef CONFIG_PM_WAKELOCKS_GC
81 #define WL_GC_COUNT_MAX 100
82 #define WL_GC_TIME_SEC 300
84 static void __wakelocks_gc(struct work_struct *work);
85 static LIST_HEAD(wakelocks_lru_list);
86 static DECLARE_WORK(wakelock_work, __wakelocks_gc);
87 static unsigned int wakelocks_gc_count;
89 static inline void wakelocks_lru_add(struct wakelock *wl)
91 list_add(&wl->lru, &wakelocks_lru_list);
94 static inline void wakelocks_lru_most_recent(struct wakelock *wl)
96 list_move(&wl->lru, &wakelocks_lru_list);
99 static void __wakelocks_gc(struct work_struct *work)
101 struct wakelock *wl, *aux;
104 mutex_lock(&wakelocks_lock);
107 list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
111 spin_lock_irq(&wl->ws.lock);
112 idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws.last_time));
113 active = wl->ws.active;
114 spin_unlock_irq(&wl->ws.lock);
116 if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
120 wakeup_source_remove(&wl->ws);
121 rb_erase(&wl->node, &wakelocks_tree);
125 decrement_wakelocks_number();
128 wakelocks_gc_count = 0;
130 mutex_unlock(&wakelocks_lock);
133 static void wakelocks_gc(void)
135 if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
138 schedule_work(&wakelock_work);
140 #else /* !CONFIG_PM_WAKELOCKS_GC */
141 static inline void wakelocks_lru_add(struct wakelock *wl) {}
142 static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
143 static inline void wakelocks_gc(void) {}
144 #endif /* !CONFIG_PM_WAKELOCKS_GC */
146 static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
147 bool add_if_not_found)
149 struct rb_node **node = &wakelocks_tree.rb_node;
150 struct rb_node *parent = *node;
157 wl = rb_entry(*node, struct wakelock, node);
158 diff = strncmp(name, wl->name, len);
166 node = &(*node)->rb_left;
168 node = &(*node)->rb_right;
170 if (!add_if_not_found)
171 return ERR_PTR(-EINVAL);
173 if (wakelocks_limit_exceeded())
174 return ERR_PTR(-ENOSPC);
176 /* Not found, we have to add a new one. */
177 wl = kzalloc(sizeof(*wl), GFP_KERNEL);
179 return ERR_PTR(-ENOMEM);
181 wl->name = kstrndup(name, len, GFP_KERNEL);
184 return ERR_PTR(-ENOMEM);
186 wl->ws.name = wl->name;
187 wl->ws.last_time = ktime_get();
188 wakeup_source_add(&wl->ws);
189 rb_link_node(&wl->node, parent, node);
190 rb_insert_color(&wl->node, &wakelocks_tree);
191 wakelocks_lru_add(wl);
192 increment_wakelocks_number();
196 int pm_wake_lock(const char *buf)
198 const char *str = buf;
204 if (!capable(CAP_BLOCK_SUSPEND))
207 while (*str && !isspace(*str))
214 if (*str && *str != '\n') {
215 /* Find out if there's a valid timeout string appended. */
216 ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
221 mutex_lock(&wakelocks_lock);
223 wl = wakelock_lookup_add(buf, len, true);
229 u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
231 do_div(timeout_ms, NSEC_PER_MSEC);
232 __pm_wakeup_event(&wl->ws, timeout_ms);
234 __pm_stay_awake(&wl->ws);
237 wakelocks_lru_most_recent(wl);
240 mutex_unlock(&wakelocks_lock);
244 int pm_wake_unlock(const char *buf)
250 if (!capable(CAP_BLOCK_SUSPEND))
257 if (buf[len-1] == '\n')
263 mutex_lock(&wakelocks_lock);
265 wl = wakelock_lookup_add(buf, len, false);
272 wakelocks_lru_most_recent(wl);
276 mutex_unlock(&wakelocks_lock);