projects/linux·blob v3.13 · refs

266 lines · 5.4 KiB

1/*
2 * kernel/power/wakelock.c
3 *
4 * User space wakeup sources support.
5 *
6 * Copyright (C) 2012 Rafael J. Wysocki <[email protected]>
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}