[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 "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 LIST_HEAD(wakelocks_lru_list);
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(void)
{
	struct wakelock *wl, *aux;
	ktime_t now;

	if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
		return;

	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;
}
#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>
	20
6c5be291 RK	21	#include "power.h"
6c5be291 RK	22
b86ff982 RW	23	static DEFINE_MUTEX(wakelocks_lock);
	24
	25	struct wakelock {
	26	char *name;
	27	struct rb_node node;
	28	struct wakeup_source ws;
4e585d25	29	#ifdef CONFIG_PM_WAKELOCKS_GC
b86ff982	30	struct list_head lru;
4e585d25	31	#endif
b86ff982 RW	32	};
	33
	34	static struct rb_root wakelocks_tree = RB_ROOT;
b86ff982 RW	35
	36	ssize_t pm_show_wakelocks(char *buf, bool show_active)
	37	{
	38	struct rb_node *node;
	39	struct wakelock *wl;
	40	char *str = buf;
	41	char *end = buf + PAGE_SIZE;
	42
	43	mutex_lock(&wakelocks_lock);
	44
	45	for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
	46	wl = rb_entry(node, struct wakelock, node);
	47	if (wl->ws.active == show_active)
	48	str += scnprintf(str, end - str, "%s ", wl->name);
	49	}
	50	if (str > buf)
	51	str--;
	52
	53	str += scnprintf(str, end - str, "\n");
	54
	55	mutex_unlock(&wakelocks_lock);
	56	return (str - buf);
	57	}
	58
c73893e2 RW	59	#if CONFIG_PM_WAKELOCKS_LIMIT > 0
	60	static unsigned int number_of_wakelocks;
	61
	62	static inline bool wakelocks_limit_exceeded(void)
	63	{
	64	return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
	65	}
	66
	67	static inline void increment_wakelocks_number(void)
	68	{
	69	number_of_wakelocks++;
	70	}
	71
	72	static inline void decrement_wakelocks_number(void)
	73	{
	74	number_of_wakelocks--;
	75	}
	76	#else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
	77	static inline bool wakelocks_limit_exceeded(void) { return false; }
	78	static inline void increment_wakelocks_number(void) {}
	79	static inline void decrement_wakelocks_number(void) {}
	80	#endif /* CONFIG_PM_WAKELOCKS_LIMIT */
	81
4e585d25 RW	82	#ifdef CONFIG_PM_WAKELOCKS_GC
	83	#define WL_GC_COUNT_MAX 100
	84	#define WL_GC_TIME_SEC 300
	85
	86	static LIST_HEAD(wakelocks_lru_list);
	87	static unsigned int wakelocks_gc_count;
	88
	89	static inline void wakelocks_lru_add(struct wakelock *wl)
	90	{
	91	list_add(&wl->lru, &wakelocks_lru_list);
	92	}
	93
	94	static inline void wakelocks_lru_most_recent(struct wakelock *wl)
	95	{
	96	list_move(&wl->lru, &wakelocks_lru_list);
	97	}
	98
	99	static void wakelocks_gc(void)
	100	{
	101	struct wakelock wl, aux;
	102	ktime_t now;
	103
	104	if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
	105	return;
	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_remove(&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	#else /* !CONFIG_PM_WAKELOCKS_GC */
	132	static inline void wakelocks_lru_add(struct wakelock *wl) {}
	133	static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
	134	static inline void wakelocks_gc(void) {}
	135	#endif /* !CONFIG_PM_WAKELOCKS_GC */
	136
b86ff982 RW	137	static struct wakelock wakelock_lookup_add(const char name, size_t len,
	138	bool add_if_not_found)
	139	{
	140	struct rb_node **node = &wakelocks_tree.rb_node;
	141	struct rb_node parent = node;
	142	struct wakelock *wl;
	143
	144	while (*node) {
	145	int diff;
	146
	147	parent = *node;
	148	wl = rb_entry(*node, struct wakelock, node);
	149	diff = strncmp(name, wl->name, len);
	150	if (diff == 0) {
	151	if (wl->name[len])
	152	diff = -1;
	153	else
	154	return wl;
	155	}
	156	if (diff < 0)
	157	node = &(*node)->rb_left;
	158	else
	159	node = &(*node)->rb_right;
	160	}
	161	if (!add_if_not_found)
	162	return ERR_PTR(-EINVAL);
	163
c73893e2	164	if (wakelocks_limit_exceeded())
b86ff982 RW	165	return ERR_PTR(-ENOSPC);
	166
	167	/* Not found, we have to add a new one. */
	168	wl = kzalloc(sizeof(*wl), GFP_KERNEL);
	169	if (!wl)
	170	return ERR_PTR(-ENOMEM);
	171
	172	wl->name = kstrndup(name, len, GFP_KERNEL);
	173	if (!wl->name) {
	174	kfree(wl);
	175	return ERR_PTR(-ENOMEM);
	176	}
	177	wl->ws.name = wl->name;
	178	wakeup_source_add(&wl->ws);
	179	rb_link_node(&wl->node, parent, node);
	180	rb_insert_color(&wl->node, &wakelocks_tree);
4e585d25	181	wakelocks_lru_add(wl);
c73893e2	182	increment_wakelocks_number();
b86ff982 RW	183	return wl;
	184	}
	185
	186	int pm_wake_lock(const char *buf)
	187	{
	188	const char *str = buf;
	189	struct wakelock *wl;
	190	u64 timeout_ns = 0;
	191	size_t len;
	192	int ret = 0;
	193
11388c87 RW	194	if (!capable(CAP_BLOCK_SUSPEND))
	195	return -EPERM;
	196
b86ff982 RW	197	while (str && !isspace(str))
	198	str++;
	199
	200	len = str - buf;
	201	if (!len)
	202	return -EINVAL;
	203
	204	if (str && str != '\n') {
	205	/* Find out if there's a valid timeout string appended. */
	206	ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
	207	if (ret)
	208	return -EINVAL;
	209	}
	210
	211	mutex_lock(&wakelocks_lock);
	212
	213	wl = wakelock_lookup_add(buf, len, true);
	214	if (IS_ERR(wl)) {
	215	ret = PTR_ERR(wl);
	216	goto out;
	217	}
	218	if (timeout_ns) {
	219	u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
	220
	221	do_div(timeout_ms, NSEC_PER_MSEC);
	222	__pm_wakeup_event(&wl->ws, timeout_ms);
	223	} else {
	224	__pm_stay_awake(&wl->ws);
	225	}
	226
4e585d25	227	wakelocks_lru_most_recent(wl);
b86ff982 RW	228
	229	out:
	230	mutex_unlock(&wakelocks_lock);
	231	return ret;
	232	}
	233
b86ff982 RW	234	int pm_wake_unlock(const char *buf)
	235	{
	236	struct wakelock *wl;
	237	size_t len;
	238	int ret = 0;
	239
11388c87 RW	240	if (!capable(CAP_BLOCK_SUSPEND))
	241	return -EPERM;
	242
b86ff982 RW	243	len = strlen(buf);
	244	if (!len)
	245	return -EINVAL;
	246
	247	if (buf[len-1] == '\n')
	248	len--;
	249
	250	if (!len)
	251	return -EINVAL;
	252
	253	mutex_lock(&wakelocks_lock);
	254
	255	wl = wakelock_lookup_add(buf, len, false);
	256	if (IS_ERR(wl)) {
	257	ret = PTR_ERR(wl);
	258	goto out;
	259	}
	260	__pm_relax(&wl->ws);
4e585d25 RW	261
	262	wakelocks_lru_most_recent(wl);
	263	wakelocks_gc();
b86ff982 RW	264
	265	out:
	266	mutex_unlock(&wakelocks_lock);
	267	return ret;
	268	}