aboutsummaryrefslogtreecommitdiff
path: root/kernel/power/wakelock.c
blob: 1896386e16bbe0ddd6173cf7a9e95d42617488a4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
/*
 * kernel/power/wakelock.c
 *
 * User space wakeup sources support.
 *
 * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
 *
 * This code is based on the analogous interface allowing user space to
 * manipulate wakelocks on Android.
 */

#include <linux/capability.h>
#include <linux/ctype.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/hrtimer.h>
#include <linux/list.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#include <linux/workqueue.h>

#include "power.h"

static DEFINE_MUTEX(wakelocks_lock);

struct wakelock {
	char			*name;
	struct rb_node		node;
	struct wakeup_source	ws;
#ifdef CONFIG_PM_WAKELOCKS_GC
	struct list_head	lru;
#endif
};

static struct rb_root wakelocks_tree = RB_ROOT;

ssize_t pm_show_wakelocks(char *buf, bool show_active)
{
	struct rb_node *node;
	struct wakelock *wl;
	char *str = buf;
	char *end = buf + PAGE_SIZE;

	mutex_lock(&wakelocks_lock);

	for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
		wl = rb_entry(node, struct wakelock, node);
		if (wl->ws.active == show_active)
			str += scnprintf(str, end - str, "%s ", wl->name);
	}
	if (str > buf)
		str--;

	str += scnprintf(str, end - str, "\n");

	mutex_unlock(&wakelocks_lock);
	return (str - buf);
}

#if CONFIG_PM_WAKELOCKS_LIMIT > 0
static unsigned int number_of_wakelocks;

static inline bool wakelocks_limit_exceeded(void)
{
	return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
}

static inline void increment_wakelocks_number(void)
{
	number_of_wakelocks++;
}

static inline void decrement_wakelocks_number(void)
{
	number_of_wakelocks--;
}
#else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
static inline bool wakelocks_limit_exceeded(void) { return false; }
static inline void increment_wakelocks_number(void) {}
static inline void decrement_wakelocks_number(void) {}
#endif /* CONFIG_PM_WAKELOCKS_LIMIT */

#ifdef CONFIG_PM_WAKELOCKS_GC
#define WL_GC_COUNT_MAX	100
#define WL_GC_TIME_SEC	300

static void __wakelocks_gc(struct work_struct *work);
static LIST_HEAD(wakelocks_lru_list);
static DECLARE_WORK(wakelock_work, __wakelocks_gc);
static unsigned int wakelocks_gc_count;

static inline void wakelocks_lru_add(struct wakelock *wl)
{
	list_add(&wl->lru, &wakelocks_lru_list);
}

static inline void wakelocks_lru_most_recent(struct wakelock *wl)
{
	list_move(&wl->lru, &wakelocks_lru_list);
}

static void __wakelocks_gc(struct work_struct *work)
{
	struct wakelock *wl, *aux;
	ktime_t now;

	mutex_lock(&wakelocks_lock);

	now = ktime_get();
	list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
		u64 idle_time_ns;
		bool active;

		spin_lock_irq(&wl->ws.lock);
		idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws.last_time));
		active = wl->ws.active;
		spin_unlock_irq(&wl->ws.lock);

		if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
			break;

		if (!active) {
			wakeup_source_remove(&wl->ws);
			rb_erase(&wl->node, &wakelocks_tree);
			list_del(&wl->lru);
			kfree(wl->name);
			kfree(wl);
			decrement_wakelocks_number();
		}
	}
	wakelocks_gc_count = 0;

	mutex_unlock(&wakelocks_lock);
}

static void wakelocks_gc(void)
{
	if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
		return;

	schedule_work(&wakelock_work);
}
#else /* !CONFIG_PM_WAKELOCKS_GC */
static inline void wakelocks_lru_add(struct wakelock *wl) {}
static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
static inline void wakelocks_gc(void) {}
#endif /* !CONFIG_PM_WAKELOCKS_GC */

static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
					    bool add_if_not_found)
{
	struct rb_node **node = &wakelocks_tree.rb_node;
	struct rb_node *parent = *node;
	struct wakelock *wl;

	while (*node) {
		int diff;

		parent = *node;
		wl = rb_entry(*node, struct wakelock, node);
		diff = strncmp(name, wl->name, len);
		if (diff == 0) {
			if (wl->name[len])
				diff = -1;
			else
				return wl;
		}
		if (diff < 0)
			node = &(*node)->rb_left;
		else
			node = &(*node)->rb_right;
	}
	if (!add_if_not_found)
		return ERR_PTR(-EINVAL);

	if (wakelocks_limit_exceeded())
		return ERR_PTR(-ENOSPC);

	/* Not found, we have to add a new one. */
	wl = kzalloc(sizeof(*wl), GFP_KERNEL);
	if (!wl)
		return ERR_PTR(-ENOMEM);

	wl->name = kstrndup(name, len, GFP_KERNEL);
	if (!wl->name) {
		kfree(wl);
		return ERR_PTR(-ENOMEM);
	}
	wl->ws.name = wl->name;
	wakeup_source_add(&wl->ws);
	rb_link_node(&wl->node, parent, node);
	rb_insert_color(&wl->node, &wakelocks_tree);
	wakelocks_lru_add(wl);
	increment_wakelocks_number();
	return wl;
}

int pm_wake_lock(const char *buf)
{
	const char *str = buf;
	struct wakelock *wl;
	u64 timeout_ns = 0;
	size_t len;
	int ret = 0;

	if (!capable(CAP_BLOCK_SUSPEND))
		return -EPERM;

	while (*str && !isspace(*str))
		str++;

	len = str - buf;
	if (!len)
		return -EINVAL;

	if (*str && *str != '\n') {
		/* Find out if there's a valid timeout string appended. */
		ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
		if (ret)
			return -EINVAL;
	}

	mutex_lock(&wakelocks_lock);

	wl = wakelock_lookup_add(buf, len, true);
	if (IS_ERR(wl)) {
		ret = PTR_ERR(wl);
		goto out;
	}
	if (timeout_ns) {
		u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;

		do_div(timeout_ms, NSEC_PER_MSEC);
		__pm_wakeup_event(&wl->ws, timeout_ms);
	} else {
		__pm_stay_awake(&wl->ws);
	}

	wakelocks_lru_most_recent(wl);

 out:
	mutex_unlock(&wakelocks_lock);
	return ret;
}

int pm_wake_unlock(const char *buf)
{
	struct wakelock *wl;
	size_t len;
	int ret = 0;

	if (!capable(CAP_BLOCK_SUSPEND))
		return -EPERM;

	len = strlen(buf);
	if (!len)
		return -EINVAL;

	if (buf[len-1] == '\n')
		len--;

	if (!len)
		return -EINVAL;

	mutex_lock(&wakelocks_lock);

	wl = wakelock_lookup_add(buf, len, false);
	if (IS_ERR(wl)) {
		ret = PTR_ERR(wl);
		goto out;
	}
	__pm_relax(&wl->ws);

	wakelocks_lru_most_recent(wl);
	wakelocks_gc();

 out:
	mutex_unlock(&wakelocks_lock);
	return ret;
}