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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * kernel/power/wakelock.c
4 *
5 * User space wakeup sources support.
6 *
7 * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
8 *
9 * This code is based on the analogous interface allowing user space to
10 * manipulate wakelocks on Android.
11 */
12
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>
22
23#include "power.h"
24
25static DEFINE_MUTEX(wakelocks_lock);
26
27struct wakelock {
28 char *name;
29 struct rb_node node;
30 struct wakeup_source *ws;
31#ifdef CONFIG_PM_WAKELOCKS_GC
32 struct list_head lru;
33#endif
34};
35
36static struct rb_root wakelocks_tree = RB_ROOT;
37
38ssize_t pm_show_wakelocks(char *buf, bool show_active)
39{
40 struct rb_node *node;
41 struct wakelock *wl;
42 int len = 0;
43
44 mutex_lock(&wakelocks_lock);
45
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);
50 }
51
52 len += sysfs_emit_at(buf, len, "\n");
53
54 mutex_unlock(&wakelocks_lock);
55 return len;
56}
57
58#if CONFIG_PM_WAKELOCKS_LIMIT > 0
59static unsigned int number_of_wakelocks;
60
61static inline bool wakelocks_limit_exceeded(void)
62{
63 return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
64}
65
66static inline void increment_wakelocks_number(void)
67{
68 number_of_wakelocks++;
69}
70
71static inline void decrement_wakelocks_number(void)
72{
73 number_of_wakelocks--;
74}
75#else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
76static inline bool wakelocks_limit_exceeded(void) { return false; }
77static inline void increment_wakelocks_number(void) {}
78static inline void decrement_wakelocks_number(void) {}
79#endif /* CONFIG_PM_WAKELOCKS_LIMIT */
80
81#ifdef CONFIG_PM_WAKELOCKS_GC
82#define WL_GC_COUNT_MAX 100
83#define WL_GC_TIME_SEC 300
84
85static void __wakelocks_gc(struct work_struct *work);
86static LIST_HEAD(wakelocks_lru_list);
87static DECLARE_WORK(wakelock_work, __wakelocks_gc);
88static unsigned int wakelocks_gc_count;
89
90static inline void wakelocks_lru_add(struct wakelock *wl)
91{
92 list_add(&wl->lru, &wakelocks_lru_list);
93}
94
95static inline void wakelocks_lru_most_recent(struct wakelock *wl)
96{
97 list_move(&wl->lru, &wakelocks_lru_list);
98}
99
100static void __wakelocks_gc(struct work_struct *work)
101{
102 struct wakelock *wl, *aux;
103 ktime_t now;
104
105 mutex_lock(&wakelocks_lock);
106
107 now = ktime_get();
108 list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
109 u64 idle_time_ns;
110 bool active;
111
112 spin_lock_irq(&wl->ws->lock);
113 idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws->last_time));
114 active = wl->ws->active;
115 spin_unlock_irq(&wl->ws->lock);
116
117 if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
118 break;
119
120 if (!active) {
121 wakeup_source_unregister(wl->ws);
122 rb_erase(&wl->node, &wakelocks_tree);
123 list_del(&wl->lru);
124 kfree(wl->name);
125 kfree(wl);
126 decrement_wakelocks_number();
127 }
128 }
129 wakelocks_gc_count = 0;
130
131 mutex_unlock(&wakelocks_lock);
132}
133
134static void wakelocks_gc(void)
135{
136 if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
137 return;
138
139 schedule_work(&wakelock_work);
140}
141#else /* !CONFIG_PM_WAKELOCKS_GC */
142static inline void wakelocks_lru_add(struct wakelock *wl) {}
143static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
144static inline void wakelocks_gc(void) {}
145#endif /* !CONFIG_PM_WAKELOCKS_GC */
146
147static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
148 bool add_if_not_found)
149{
150 struct rb_node **node = &wakelocks_tree.rb_node;
151 struct rb_node *parent = *node;
152 struct wakelock *wl;
153
154 while (*node) {
155 int diff;
156
157 parent = *node;
158 wl = rb_entry(*node, struct wakelock, node);
159 diff = strncmp(name, wl->name, len);
160 if (diff == 0) {
161 if (wl->name[len])
162 diff = -1;
163 else
164 return wl;
165 }
166 if (diff < 0)
167 node = &(*node)->rb_left;
168 else
169 node = &(*node)->rb_right;
170 }
171 if (!add_if_not_found)
172 return ERR_PTR(-EINVAL);
173
174 if (wakelocks_limit_exceeded())
175 return ERR_PTR(-ENOSPC);
176
177 /* Not found, we have to add a new one. */
178 wl = kzalloc(sizeof(*wl), GFP_KERNEL);
179 if (!wl)
180 return ERR_PTR(-ENOMEM);
181
182 wl->name = kstrndup(name, len, GFP_KERNEL);
183 if (!wl->name) {
184 kfree(wl);
185 return ERR_PTR(-ENOMEM);
186 }
187
188 wl->ws = wakeup_source_register(NULL, wl->name);
189 if (!wl->ws) {
190 kfree(wl->name);
191 kfree(wl);
192 return ERR_PTR(-ENOMEM);
193 }
194 wl->ws->last_time = ktime_get();
195
196 rb_link_node(&wl->node, parent, node);
197 rb_insert_color(&wl->node, &wakelocks_tree);
198 wakelocks_lru_add(wl);
199 increment_wakelocks_number();
200 return wl;
201}
202
203int pm_wake_lock(const char *buf)
204{
205 const char *str = buf;
206 struct wakelock *wl;
207 u64 timeout_ns = 0;
208 size_t len;
209 int ret = 0;
210
211 if (!capable(CAP_BLOCK_SUSPEND))
212 return -EPERM;
213
214 while (*str && !isspace(*str))
215 str++;
216
217 len = str - buf;
218 if (!len)
219 return -EINVAL;
220
221 if (*str && *str != '\n') {
222 /* Find out if there's a valid timeout string appended. */
223 ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
224 if (ret)
225 return -EINVAL;
226 }
227
228 mutex_lock(&wakelocks_lock);
229
230 wl = wakelock_lookup_add(buf, len, true);
231 if (IS_ERR(wl)) {
232 ret = PTR_ERR(wl);
233 goto out;
234 }
235 if (timeout_ns) {
236 u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
237
238 do_div(timeout_ms, NSEC_PER_MSEC);
239 __pm_wakeup_event(wl->ws, timeout_ms);
240 } else {
241 __pm_stay_awake(wl->ws);
242 }
243
244 wakelocks_lru_most_recent(wl);
245
246 out:
247 mutex_unlock(&wakelocks_lock);
248 return ret;
249}
250
251int pm_wake_unlock(const char *buf)
252{
253 struct wakelock *wl;
254 size_t len;
255 int ret = 0;
256
257 if (!capable(CAP_BLOCK_SUSPEND))
258 return -EPERM;
259
260 len = strlen(buf);
261 if (!len)
262 return -EINVAL;
263
264 if (buf[len-1] == '\n')
265 len--;
266
267 if (!len)
268 return -EINVAL;
269
270 mutex_lock(&wakelocks_lock);
271
272 wl = wakelock_lookup_add(buf, len, false);
273 if (IS_ERR(wl)) {
274 ret = PTR_ERR(wl);
275 goto out;
276 }
277 __pm_relax(wl->ws);
278
279 wakelocks_lru_most_recent(wl);
280 wakelocks_gc();
281
282 out:
283 mutex_unlock(&wakelocks_lock);
284 return ret;
285}
1/*
2 * kernel/power/wakelock.c
3 *
4 * User space wakeup sources support.
5 *
6 * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
7 *
8 * This code is based on the analogous interface allowing user space to
9 * manipulate wakelocks on Android.
10 */
11
12#include <linux/capability.h>
13#include <linux/ctype.h>
14#include <linux/device.h>
15#include <linux/err.h>
16#include <linux/hrtimer.h>
17#include <linux/list.h>
18#include <linux/rbtree.h>
19#include <linux/slab.h>
20
21static DEFINE_MUTEX(wakelocks_lock);
22
23struct wakelock {
24 char *name;
25 struct rb_node node;
26 struct wakeup_source ws;
27#ifdef CONFIG_PM_WAKELOCKS_GC
28 struct list_head lru;
29#endif
30};
31
32static struct rb_root wakelocks_tree = RB_ROOT;
33
34ssize_t pm_show_wakelocks(char *buf, bool show_active)
35{
36 struct rb_node *node;
37 struct wakelock *wl;
38 char *str = buf;
39 char *end = buf + PAGE_SIZE;
40
41 mutex_lock(&wakelocks_lock);
42
43 for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
44 wl = rb_entry(node, struct wakelock, node);
45 if (wl->ws.active == show_active)
46 str += scnprintf(str, end - str, "%s ", wl->name);
47 }
48 if (str > buf)
49 str--;
50
51 str += scnprintf(str, end - str, "\n");
52
53 mutex_unlock(&wakelocks_lock);
54 return (str - buf);
55}
56
57#if CONFIG_PM_WAKELOCKS_LIMIT > 0
58static unsigned int number_of_wakelocks;
59
60static inline bool wakelocks_limit_exceeded(void)
61{
62 return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
63}
64
65static inline void increment_wakelocks_number(void)
66{
67 number_of_wakelocks++;
68}
69
70static inline void decrement_wakelocks_number(void)
71{
72 number_of_wakelocks--;
73}
74#else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
75static inline bool wakelocks_limit_exceeded(void) { return false; }
76static inline void increment_wakelocks_number(void) {}
77static inline void decrement_wakelocks_number(void) {}
78#endif /* CONFIG_PM_WAKELOCKS_LIMIT */
79
80#ifdef CONFIG_PM_WAKELOCKS_GC
81#define WL_GC_COUNT_MAX 100
82#define WL_GC_TIME_SEC 300
83
84static LIST_HEAD(wakelocks_lru_list);
85static unsigned int wakelocks_gc_count;
86
87static inline void wakelocks_lru_add(struct wakelock *wl)
88{
89 list_add(&wl->lru, &wakelocks_lru_list);
90}
91
92static inline void wakelocks_lru_most_recent(struct wakelock *wl)
93{
94 list_move(&wl->lru, &wakelocks_lru_list);
95}
96
97static void wakelocks_gc(void)
98{
99 struct wakelock *wl, *aux;
100 ktime_t now;
101
102 if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
103 return;
104
105 now = ktime_get();
106 list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
107 u64 idle_time_ns;
108 bool active;
109
110 spin_lock_irq(&wl->ws.lock);
111 idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws.last_time));
112 active = wl->ws.active;
113 spin_unlock_irq(&wl->ws.lock);
114
115 if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
116 break;
117
118 if (!active) {
119 wakeup_source_remove(&wl->ws);
120 rb_erase(&wl->node, &wakelocks_tree);
121 list_del(&wl->lru);
122 kfree(wl->name);
123 kfree(wl);
124 decrement_wakelocks_number();
125 }
126 }
127 wakelocks_gc_count = 0;
128}
129#else /* !CONFIG_PM_WAKELOCKS_GC */
130static inline void wakelocks_lru_add(struct wakelock *wl) {}
131static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
132static inline void wakelocks_gc(void) {}
133#endif /* !CONFIG_PM_WAKELOCKS_GC */
134
135static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
136 bool add_if_not_found)
137{
138 struct rb_node **node = &wakelocks_tree.rb_node;
139 struct rb_node *parent = *node;
140 struct wakelock *wl;
141
142 while (*node) {
143 int diff;
144
145 parent = *node;
146 wl = rb_entry(*node, struct wakelock, node);
147 diff = strncmp(name, wl->name, len);
148 if (diff == 0) {
149 if (wl->name[len])
150 diff = -1;
151 else
152 return wl;
153 }
154 if (diff < 0)
155 node = &(*node)->rb_left;
156 else
157 node = &(*node)->rb_right;
158 }
159 if (!add_if_not_found)
160 return ERR_PTR(-EINVAL);
161
162 if (wakelocks_limit_exceeded())
163 return ERR_PTR(-ENOSPC);
164
165 /* Not found, we have to add a new one. */
166 wl = kzalloc(sizeof(*wl), GFP_KERNEL);
167 if (!wl)
168 return ERR_PTR(-ENOMEM);
169
170 wl->name = kstrndup(name, len, GFP_KERNEL);
171 if (!wl->name) {
172 kfree(wl);
173 return ERR_PTR(-ENOMEM);
174 }
175 wl->ws.name = wl->name;
176 wakeup_source_add(&wl->ws);
177 rb_link_node(&wl->node, parent, node);
178 rb_insert_color(&wl->node, &wakelocks_tree);
179 wakelocks_lru_add(wl);
180 increment_wakelocks_number();
181 return wl;
182}
183
184int pm_wake_lock(const char *buf)
185{
186 const char *str = buf;
187 struct wakelock *wl;
188 u64 timeout_ns = 0;
189 size_t len;
190 int ret = 0;
191
192 if (!capable(CAP_BLOCK_SUSPEND))
193 return -EPERM;
194
195 while (*str && !isspace(*str))
196 str++;
197
198 len = str - buf;
199 if (!len)
200 return -EINVAL;
201
202 if (*str && *str != '\n') {
203 /* Find out if there's a valid timeout string appended. */
204 ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
205 if (ret)
206 return -EINVAL;
207 }
208
209 mutex_lock(&wakelocks_lock);
210
211 wl = wakelock_lookup_add(buf, len, true);
212 if (IS_ERR(wl)) {
213 ret = PTR_ERR(wl);
214 goto out;
215 }
216 if (timeout_ns) {
217 u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
218
219 do_div(timeout_ms, NSEC_PER_MSEC);
220 __pm_wakeup_event(&wl->ws, timeout_ms);
221 } else {
222 __pm_stay_awake(&wl->ws);
223 }
224
225 wakelocks_lru_most_recent(wl);
226
227 out:
228 mutex_unlock(&wakelocks_lock);
229 return ret;
230}
231
232int pm_wake_unlock(const char *buf)
233{
234 struct wakelock *wl;
235 size_t len;
236 int ret = 0;
237
238 if (!capable(CAP_BLOCK_SUSPEND))
239 return -EPERM;
240
241 len = strlen(buf);
242 if (!len)
243 return -EINVAL;
244
245 if (buf[len-1] == '\n')
246 len--;
247
248 if (!len)
249 return -EINVAL;
250
251 mutex_lock(&wakelocks_lock);
252
253 wl = wakelock_lookup_add(buf, len, false);
254 if (IS_ERR(wl)) {
255 ret = PTR_ERR(wl);
256 goto out;
257 }
258 __pm_relax(&wl->ws);
259
260 wakelocks_lru_most_recent(wl);
261 wakelocks_gc();
262
263 out:
264 mutex_unlock(&wakelocks_lock);
265 return ret;
266}