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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
b86ff982 RW |
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 | ||
11388c87 | 13 | #include <linux/capability.h> |
b86ff982 RW |
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> | |
6ce12a97 | 21 | #include <linux/workqueue.h> |
b86ff982 | 22 | |
6c5be291 RK |
23 | #include "power.h" |
24 | ||
b86ff982 RW |
25 | static DEFINE_MUTEX(wakelocks_lock); |
26 | ||
27 | struct wakelock { | |
28 | char *name; | |
29 | struct rb_node node; | |
30 | struct wakeup_source ws; | |
4e585d25 | 31 | #ifdef CONFIG_PM_WAKELOCKS_GC |
b86ff982 | 32 | struct list_head lru; |
4e585d25 | 33 | #endif |
b86ff982 RW |
34 | }; |
35 | ||
36 | static struct rb_root wakelocks_tree = RB_ROOT; | |
b86ff982 RW |
37 | |
38 | ssize_t pm_show_wakelocks(char *buf, bool show_active) | |
39 | { | |
40 | struct rb_node *node; | |
41 | struct wakelock *wl; | |
42 | char *str = buf; | |
43 | char *end = buf + PAGE_SIZE; | |
44 | ||
45 | mutex_lock(&wakelocks_lock); | |
46 | ||
47 | for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) { | |
48 | wl = rb_entry(node, struct wakelock, node); | |
49 | if (wl->ws.active == show_active) | |
50 | str += scnprintf(str, end - str, "%s ", wl->name); | |
51 | } | |
52 | if (str > buf) | |
53 | str--; | |
54 | ||
55 | str += scnprintf(str, end - str, "\n"); | |
56 | ||
57 | mutex_unlock(&wakelocks_lock); | |
58 | return (str - buf); | |
59 | } | |
60 | ||
c73893e2 RW |
61 | #if CONFIG_PM_WAKELOCKS_LIMIT > 0 |
62 | static unsigned int number_of_wakelocks; | |
63 | ||
64 | static inline bool wakelocks_limit_exceeded(void) | |
65 | { | |
66 | return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT; | |
67 | } | |
68 | ||
69 | static inline void increment_wakelocks_number(void) | |
70 | { | |
71 | number_of_wakelocks++; | |
72 | } | |
73 | ||
74 | static inline void decrement_wakelocks_number(void) | |
75 | { | |
76 | number_of_wakelocks--; | |
77 | } | |
78 | #else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */ | |
79 | static inline bool wakelocks_limit_exceeded(void) { return false; } | |
80 | static inline void increment_wakelocks_number(void) {} | |
81 | static inline void decrement_wakelocks_number(void) {} | |
82 | #endif /* CONFIG_PM_WAKELOCKS_LIMIT */ | |
83 | ||
4e585d25 RW |
84 | #ifdef CONFIG_PM_WAKELOCKS_GC |
85 | #define WL_GC_COUNT_MAX 100 | |
86 | #define WL_GC_TIME_SEC 300 | |
87 | ||
6ce12a97 | 88 | static void __wakelocks_gc(struct work_struct *work); |
4e585d25 | 89 | static LIST_HEAD(wakelocks_lru_list); |
6ce12a97 | 90 | static DECLARE_WORK(wakelock_work, __wakelocks_gc); |
4e585d25 RW |
91 | static unsigned int wakelocks_gc_count; |
92 | ||
93 | static inline void wakelocks_lru_add(struct wakelock *wl) | |
94 | { | |
95 | list_add(&wl->lru, &wakelocks_lru_list); | |
96 | } | |
97 | ||
98 | static inline void wakelocks_lru_most_recent(struct wakelock *wl) | |
99 | { | |
100 | list_move(&wl->lru, &wakelocks_lru_list); | |
101 | } | |
102 | ||
6ce12a97 | 103 | static void __wakelocks_gc(struct work_struct *work) |
4e585d25 RW |
104 | { |
105 | struct wakelock *wl, *aux; | |
106 | ktime_t now; | |
107 | ||
6ce12a97 | 108 | mutex_lock(&wakelocks_lock); |
4e585d25 RW |
109 | |
110 | now = ktime_get(); | |
111 | list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) { | |
112 | u64 idle_time_ns; | |
113 | bool active; | |
114 | ||
115 | spin_lock_irq(&wl->ws.lock); | |
116 | idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws.last_time)); | |
117 | active = wl->ws.active; | |
118 | spin_unlock_irq(&wl->ws.lock); | |
119 | ||
120 | if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC)) | |
121 | break; | |
122 | ||
123 | if (!active) { | |
124 | wakeup_source_remove(&wl->ws); | |
125 | rb_erase(&wl->node, &wakelocks_tree); | |
126 | list_del(&wl->lru); | |
127 | kfree(wl->name); | |
128 | kfree(wl); | |
129 | decrement_wakelocks_number(); | |
130 | } | |
131 | } | |
132 | wakelocks_gc_count = 0; | |
6ce12a97 SK |
133 | |
134 | mutex_unlock(&wakelocks_lock); | |
135 | } | |
136 | ||
137 | static void wakelocks_gc(void) | |
138 | { | |
139 | if (++wakelocks_gc_count <= WL_GC_COUNT_MAX) | |
140 | return; | |
141 | ||
142 | schedule_work(&wakelock_work); | |
4e585d25 RW |
143 | } |
144 | #else /* !CONFIG_PM_WAKELOCKS_GC */ | |
145 | static inline void wakelocks_lru_add(struct wakelock *wl) {} | |
146 | static inline void wakelocks_lru_most_recent(struct wakelock *wl) {} | |
147 | static inline void wakelocks_gc(void) {} | |
148 | #endif /* !CONFIG_PM_WAKELOCKS_GC */ | |
149 | ||
b86ff982 RW |
150 | static struct wakelock *wakelock_lookup_add(const char *name, size_t len, |
151 | bool add_if_not_found) | |
152 | { | |
153 | struct rb_node **node = &wakelocks_tree.rb_node; | |
154 | struct rb_node *parent = *node; | |
155 | struct wakelock *wl; | |
156 | ||
157 | while (*node) { | |
158 | int diff; | |
159 | ||
160 | parent = *node; | |
161 | wl = rb_entry(*node, struct wakelock, node); | |
162 | diff = strncmp(name, wl->name, len); | |
163 | if (diff == 0) { | |
164 | if (wl->name[len]) | |
165 | diff = -1; | |
166 | else | |
167 | return wl; | |
168 | } | |
169 | if (diff < 0) | |
170 | node = &(*node)->rb_left; | |
171 | else | |
172 | node = &(*node)->rb_right; | |
173 | } | |
174 | if (!add_if_not_found) | |
175 | return ERR_PTR(-EINVAL); | |
176 | ||
c73893e2 | 177 | if (wakelocks_limit_exceeded()) |
b86ff982 RW |
178 | return ERR_PTR(-ENOSPC); |
179 | ||
180 | /* Not found, we have to add a new one. */ | |
181 | wl = kzalloc(sizeof(*wl), GFP_KERNEL); | |
182 | if (!wl) | |
183 | return ERR_PTR(-ENOMEM); | |
184 | ||
185 | wl->name = kstrndup(name, len, GFP_KERNEL); | |
186 | if (!wl->name) { | |
187 | kfree(wl); | |
188 | return ERR_PTR(-ENOMEM); | |
189 | } | |
190 | wl->ws.name = wl->name; | |
191 | wakeup_source_add(&wl->ws); | |
192 | rb_link_node(&wl->node, parent, node); | |
193 | rb_insert_color(&wl->node, &wakelocks_tree); | |
4e585d25 | 194 | wakelocks_lru_add(wl); |
c73893e2 | 195 | increment_wakelocks_number(); |
b86ff982 RW |
196 | return wl; |
197 | } | |
198 | ||
199 | int pm_wake_lock(const char *buf) | |
200 | { | |
201 | const char *str = buf; | |
202 | struct wakelock *wl; | |
203 | u64 timeout_ns = 0; | |
204 | size_t len; | |
205 | int ret = 0; | |
206 | ||
11388c87 RW |
207 | if (!capable(CAP_BLOCK_SUSPEND)) |
208 | return -EPERM; | |
209 | ||
b86ff982 RW |
210 | while (*str && !isspace(*str)) |
211 | str++; | |
212 | ||
213 | len = str - buf; | |
214 | if (!len) | |
215 | return -EINVAL; | |
216 | ||
217 | if (*str && *str != '\n') { | |
218 | /* Find out if there's a valid timeout string appended. */ | |
219 | ret = kstrtou64(skip_spaces(str), 10, &timeout_ns); | |
220 | if (ret) | |
221 | return -EINVAL; | |
222 | } | |
223 | ||
224 | mutex_lock(&wakelocks_lock); | |
225 | ||
226 | wl = wakelock_lookup_add(buf, len, true); | |
227 | if (IS_ERR(wl)) { | |
228 | ret = PTR_ERR(wl); | |
229 | goto out; | |
230 | } | |
231 | if (timeout_ns) { | |
232 | u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1; | |
233 | ||
234 | do_div(timeout_ms, NSEC_PER_MSEC); | |
235 | __pm_wakeup_event(&wl->ws, timeout_ms); | |
236 | } else { | |
237 | __pm_stay_awake(&wl->ws); | |
238 | } | |
239 | ||
4e585d25 | 240 | wakelocks_lru_most_recent(wl); |
b86ff982 RW |
241 | |
242 | out: | |
243 | mutex_unlock(&wakelocks_lock); | |
244 | return ret; | |
245 | } | |
246 | ||
b86ff982 RW |
247 | int pm_wake_unlock(const char *buf) |
248 | { | |
249 | struct wakelock *wl; | |
250 | size_t len; | |
251 | int ret = 0; | |
252 | ||
11388c87 RW |
253 | if (!capable(CAP_BLOCK_SUSPEND)) |
254 | return -EPERM; | |
255 | ||
b86ff982 RW |
256 | len = strlen(buf); |
257 | if (!len) | |
258 | return -EINVAL; | |
259 | ||
260 | if (buf[len-1] == '\n') | |
261 | len--; | |
262 | ||
263 | if (!len) | |
264 | return -EINVAL; | |
265 | ||
266 | mutex_lock(&wakelocks_lock); | |
267 | ||
268 | wl = wakelock_lookup_add(buf, len, false); | |
269 | if (IS_ERR(wl)) { | |
270 | ret = PTR_ERR(wl); | |
271 | goto out; | |
272 | } | |
273 | __pm_relax(&wl->ws); | |
4e585d25 RW |
274 | |
275 | wakelocks_lru_most_recent(wl); | |
276 | wakelocks_gc(); | |
b86ff982 RW |
277 | |
278 | out: | |
279 | mutex_unlock(&wakelocks_lock); | |
280 | return ret; | |
281 | } |