[linux-2.6-block.git] / kernel / power / wakelock.c

/*
 * 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;
}
Commit	Line	Data
b86ff982 RW	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
11388c87	12	#include <linux/capability.h>
b86ff982 RW	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>
6ce12a97	20	#include <linux/workqueue.h>
b86ff982	21
6c5be291 RK	22	#include "power.h"
6c5be291 RK	23
b86ff982 RW	24	static DEFINE_MUTEX(wakelocks_lock);
	25
	26	struct wakelock {
	27	char *name;
	28	struct rb_node node;
	29	struct wakeup_source ws;
4e585d25	30	#ifdef CONFIG_PM_WAKELOCKS_GC
b86ff982	31	struct list_head lru;
4e585d25	32	#endif
b86ff982 RW	33	};
	34
	35	static struct rb_root wakelocks_tree = RB_ROOT;
b86ff982 RW	36
	37	ssize_t pm_show_wakelocks(char *buf, bool show_active)
	38	{
	39	struct rb_node *node;
	40	struct wakelock *wl;
	41	char *str = buf;
	42	char *end = buf + PAGE_SIZE;
	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	str += scnprintf(str, end - str, "%s ", wl->name);
	50	}
	51	if (str > buf)
	52	str--;
	53
	54	str += scnprintf(str, end - str, "\n");
	55
	56	mutex_unlock(&wakelocks_lock);
	57	return (str - buf);
	58	}
	59
c73893e2 RW	60	#if CONFIG_PM_WAKELOCKS_LIMIT > 0
	61	static unsigned int number_of_wakelocks;
	62
	63	static inline bool wakelocks_limit_exceeded(void)
	64	{
	65	return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
	66	}
	67
	68	static inline void increment_wakelocks_number(void)
	69	{
	70	number_of_wakelocks++;
	71	}
	72
	73	static inline void decrement_wakelocks_number(void)
	74	{
	75	number_of_wakelocks--;
	76	}
	77	#else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
	78	static inline bool wakelocks_limit_exceeded(void) { return false; }
	79	static inline void increment_wakelocks_number(void) {}
	80	static inline void decrement_wakelocks_number(void) {}
	81	#endif /* CONFIG_PM_WAKELOCKS_LIMIT */
	82
4e585d25 RW	83	#ifdef CONFIG_PM_WAKELOCKS_GC
	84	#define WL_GC_COUNT_MAX 100
	85	#define WL_GC_TIME_SEC 300
	86
6ce12a97	87	static void __wakelocks_gc(struct work_struct *work);
4e585d25	88	static LIST_HEAD(wakelocks_lru_list);
6ce12a97	89	static DECLARE_WORK(wakelock_work, __wakelocks_gc);
4e585d25 RW	90	static unsigned int wakelocks_gc_count;
	91
	92	static inline void wakelocks_lru_add(struct wakelock *wl)
	93	{
	94	list_add(&wl->lru, &wakelocks_lru_list);
	95	}
	96
	97	static inline void wakelocks_lru_most_recent(struct wakelock *wl)
	98	{
	99	list_move(&wl->lru, &wakelocks_lru_list);
	100	}
	101
6ce12a97	102	static void __wakelocks_gc(struct work_struct *work)
4e585d25 RW	103	{
	104	struct wakelock wl, aux;
	105	ktime_t now;
	106
6ce12a97	107	mutex_lock(&wakelocks_lock);
4e585d25 RW	108
	109	now = ktime_get();
	110	list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
	111	u64 idle_time_ns;
	112	bool active;
	113
	114	spin_lock_irq(&wl->ws.lock);
	115	idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws.last_time));
	116	active = wl->ws.active;
	117	spin_unlock_irq(&wl->ws.lock);
	118
	119	if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
	120	break;
	121
	122	if (!active) {
	123	wakeup_source_remove(&wl->ws);
	124	rb_erase(&wl->node, &wakelocks_tree);
	125	list_del(&wl->lru);
	126	kfree(wl->name);
	127	kfree(wl);
	128	decrement_wakelocks_number();
	129	}
	130	}
	131	wakelocks_gc_count = 0;
6ce12a97 SK	132
	133	mutex_unlock(&wakelocks_lock);
	134	}
	135
	136	static void wakelocks_gc(void)
	137	{
	138	if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
	139	return;
	140
	141	schedule_work(&wakelock_work);
4e585d25 RW	142	}
	143	#else /* !CONFIG_PM_WAKELOCKS_GC */
	144	static inline void wakelocks_lru_add(struct wakelock *wl) {}
	145	static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
	146	static inline void wakelocks_gc(void) {}
	147	#endif /* !CONFIG_PM_WAKELOCKS_GC */
	148
b86ff982 RW	149	static struct wakelock wakelock_lookup_add(const char name, size_t len,
	150	bool add_if_not_found)
	151	{
	152	struct rb_node **node = &wakelocks_tree.rb_node;
	153	struct rb_node parent = node;
	154	struct wakelock *wl;
	155
	156	while (*node) {
	157	int diff;
	158
	159	parent = *node;
	160	wl = rb_entry(*node, struct wakelock, node);
	161	diff = strncmp(name, wl->name, len);
	162	if (diff == 0) {
	163	if (wl->name[len])
	164	diff = -1;
	165	else
	166	return wl;
	167	}
	168	if (diff < 0)
	169	node = &(*node)->rb_left;
	170	else
	171	node = &(*node)->rb_right;
	172	}
	173	if (!add_if_not_found)
	174	return ERR_PTR(-EINVAL);
	175
c73893e2	176	if (wakelocks_limit_exceeded())
b86ff982 RW	177	return ERR_PTR(-ENOSPC);
	178
	179	/* Not found, we have to add a new one. */
	180	wl = kzalloc(sizeof(*wl), GFP_KERNEL);
	181	if (!wl)
	182	return ERR_PTR(-ENOMEM);
	183
	184	wl->name = kstrndup(name, len, GFP_KERNEL);
	185	if (!wl->name) {
	186	kfree(wl);
	187	return ERR_PTR(-ENOMEM);
	188	}
	189	wl->ws.name = wl->name;
	190	wakeup_source_add(&wl->ws);
	191	rb_link_node(&wl->node, parent, node);
	192	rb_insert_color(&wl->node, &wakelocks_tree);
4e585d25	193	wakelocks_lru_add(wl);
c73893e2	194	increment_wakelocks_number();
b86ff982 RW	195	return wl;
	196	}
	197
	198	int pm_wake_lock(const char *buf)
	199	{
	200	const char *str = buf;
	201	struct wakelock *wl;
	202	u64 timeout_ns = 0;
	203	size_t len;
	204	int ret = 0;
	205
11388c87 RW	206	if (!capable(CAP_BLOCK_SUSPEND))
	207	return -EPERM;
	208
b86ff982 RW	209	while (str && !isspace(str))
	210	str++;
	211
	212	len = str - buf;
	213	if (!len)
	214	return -EINVAL;
	215
	216	if (str && str != '\n') {
	217	/* Find out if there's a valid timeout string appended. */
	218	ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
	219	if (ret)
	220	return -EINVAL;
	221	}
	222
	223	mutex_lock(&wakelocks_lock);
	224
	225	wl = wakelock_lookup_add(buf, len, true);
	226	if (IS_ERR(wl)) {
	227	ret = PTR_ERR(wl);
	228	goto out;
	229	}
	230	if (timeout_ns) {
	231	u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
	232
	233	do_div(timeout_ms, NSEC_PER_MSEC);
	234	__pm_wakeup_event(&wl->ws, timeout_ms);
	235	} else {
	236	__pm_stay_awake(&wl->ws);
	237	}
	238
4e585d25	239	wakelocks_lru_most_recent(wl);
b86ff982 RW	240
	241	out:
	242	mutex_unlock(&wakelocks_lock);
	243	return ret;
	244	}
	245
b86ff982 RW	246	int pm_wake_unlock(const char *buf)
	247	{
	248	struct wakelock *wl;
	249	size_t len;
	250	int ret = 0;
	251
11388c87 RW	252	if (!capable(CAP_BLOCK_SUSPEND))
	253	return -EPERM;
	254
b86ff982 RW	255	len = strlen(buf);
	256	if (!len)
	257	return -EINVAL;
	258
	259	if (buf[len-1] == '\n')
	260	len--;
	261
	262	if (!len)
	263	return -EINVAL;
	264
	265	mutex_lock(&wakelocks_lock);
	266
	267	wl = wakelock_lookup_add(buf, len, false);
	268	if (IS_ERR(wl)) {
	269	ret = PTR_ERR(wl);
	270	goto out;
	271	}
	272	__pm_relax(&wl->ws);
4e585d25 RW	273
	274	wakelocks_lru_most_recent(wl);
	275	wakelocks_gc();
b86ff982 RW	276
	277	out:
	278	mutex_unlock(&wakelocks_lock);
	279	return ret;
	280	}