/* * 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 > 0static 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;}