/* * 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; }