// SPDX-License-Identifier: GPL-2.0
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/*
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* kernel/power/wakelock.c
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*
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* User space wakeup sources support.
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*
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* Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
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*
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* This code is based on the analogous interface allowing user space to
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* manipulate wakelocks on Android.
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*/
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#include <linux/capability.h>
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#include <linux/ctype.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/hrtimer.h>
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#include <linux/list.h>
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#include <linux/rbtree.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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#include "power.h"
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static DEFINE_MUTEX(wakelocks_lock);
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struct wakelock {
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char *name;
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struct rb_node node;
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struct wakeup_source *ws;
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#ifdef CONFIG_PM_WAKELOCKS_GC
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struct list_head lru;
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#endif
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};
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static struct rb_root wakelocks_tree = RB_ROOT;
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ssize_t pm_show_wakelocks(char *buf, bool show_active)
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{
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struct rb_node *node;
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struct wakelock *wl;
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int len = 0;
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mutex_lock(&wakelocks_lock);
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for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
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wl = rb_entry(node, struct wakelock, node);
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if (wl->ws->active == show_active)
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len += sysfs_emit_at(buf, len, "%s ", wl->name);
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}
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len += sysfs_emit_at(buf, len, "\n");
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mutex_unlock(&wakelocks_lock);
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return len;
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}
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#if CONFIG_PM_WAKELOCKS_LIMIT > 0
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static unsigned int number_of_wakelocks;
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static inline bool wakelocks_limit_exceeded(void)
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{
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return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
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}
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static inline void increment_wakelocks_number(void)
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{
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number_of_wakelocks++;
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}
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static inline void decrement_wakelocks_number(void)
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{
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number_of_wakelocks--;
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}
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#else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
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static inline bool wakelocks_limit_exceeded(void) { return false; }
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static inline void increment_wakelocks_number(void) {}
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static inline void decrement_wakelocks_number(void) {}
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#endif /* CONFIG_PM_WAKELOCKS_LIMIT */
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#ifdef CONFIG_PM_WAKELOCKS_GC
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#define WL_GC_COUNT_MAX 100
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#define WL_GC_TIME_SEC 300
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static void __wakelocks_gc(struct work_struct *work);
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static LIST_HEAD(wakelocks_lru_list);
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static DECLARE_WORK(wakelock_work, __wakelocks_gc);
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static unsigned int wakelocks_gc_count;
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static inline void wakelocks_lru_add(struct wakelock *wl)
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{
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list_add(&wl->lru, &wakelocks_lru_list);
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}
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static inline void wakelocks_lru_most_recent(struct wakelock *wl)
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{
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list_move(&wl->lru, &wakelocks_lru_list);
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}
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static void __wakelocks_gc(struct work_struct *work)
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{
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struct wakelock *wl, *aux;
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ktime_t now;
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mutex_lock(&wakelocks_lock);
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now = ktime_get();
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list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
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u64 idle_time_ns;
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bool active;
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spin_lock_irq(&wl->ws->lock);
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idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws->last_time));
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active = wl->ws->active;
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spin_unlock_irq(&wl->ws->lock);
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if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
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break;
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if (!active) {
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wakeup_source_unregister(wl->ws);
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rb_erase(&wl->node, &wakelocks_tree);
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list_del(&wl->lru);
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kfree(wl->name);
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kfree(wl);
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decrement_wakelocks_number();
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}
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}
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wakelocks_gc_count = 0;
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mutex_unlock(&wakelocks_lock);
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}
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static void wakelocks_gc(void)
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{
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if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
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return;
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schedule_work(&wakelock_work);
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}
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#else /* !CONFIG_PM_WAKELOCKS_GC */
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static inline void wakelocks_lru_add(struct wakelock *wl) {}
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static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
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static inline void wakelocks_gc(void) {}
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#endif /* !CONFIG_PM_WAKELOCKS_GC */
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static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
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bool add_if_not_found)
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{
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struct rb_node **node = &wakelocks_tree.rb_node;
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struct rb_node *parent = *node;
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struct wakelock *wl;
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while (*node) {
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int diff;
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parent = *node;
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wl = rb_entry(*node, struct wakelock, node);
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diff = strncmp(name, wl->name, len);
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if (diff == 0) {
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if (wl->name[len])
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diff = -1;
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else
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return wl;
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}
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if (diff < 0)
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node = &(*node)->rb_left;
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else
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node = &(*node)->rb_right;
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}
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if (!add_if_not_found)
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return ERR_PTR(-EINVAL);
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if (wakelocks_limit_exceeded())
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return ERR_PTR(-ENOSPC);
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/* Not found, we have to add a new one. */
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wl = kzalloc(sizeof(*wl), GFP_KERNEL);
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if (!wl)
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return ERR_PTR(-ENOMEM);
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wl->name = kstrndup(name, len, GFP_KERNEL);
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if (!wl->name) {
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kfree(wl);
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return ERR_PTR(-ENOMEM);
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}
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wl->ws = wakeup_source_register(NULL, wl->name);
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if (!wl->ws) {
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kfree(wl->name);
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kfree(wl);
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return ERR_PTR(-ENOMEM);
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}
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wl->ws->last_time = ktime_get();
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rb_link_node(&wl->node, parent, node);
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rb_insert_color(&wl->node, &wakelocks_tree);
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wakelocks_lru_add(wl);
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increment_wakelocks_number();
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return wl;
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}
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int pm_wake_lock(const char *buf)
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{
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const char *str = buf;
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struct wakelock *wl;
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u64 timeout_ns = 0;
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size_t len;
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int ret = 0;
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if (!capable(CAP_BLOCK_SUSPEND))
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return -EPERM;
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while (*str && !isspace(*str))
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str++;
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len = str - buf;
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if (!len)
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return -EINVAL;
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if (*str && *str != '\n') {
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/* Find out if there's a valid timeout string appended. */
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ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
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if (ret)
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return -EINVAL;
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}
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mutex_lock(&wakelocks_lock);
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wl = wakelock_lookup_add(buf, len, true);
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if (IS_ERR(wl)) {
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ret = PTR_ERR(wl);
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goto out;
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}
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if (timeout_ns) {
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u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
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do_div(timeout_ms, NSEC_PER_MSEC);
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__pm_wakeup_event(wl->ws, timeout_ms);
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} else {
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__pm_stay_awake(wl->ws);
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}
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wakelocks_lru_most_recent(wl);
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out:
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mutex_unlock(&wakelocks_lock);
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return ret;
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}
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int pm_wake_unlock(const char *buf)
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{
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struct wakelock *wl;
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size_t len;
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int ret = 0;
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if (!capable(CAP_BLOCK_SUSPEND))
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return -EPERM;
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len = strlen(buf);
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if (!len)
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return -EINVAL;
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if (buf[len-1] == '\n')
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len--;
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if (!len)
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return -EINVAL;
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mutex_lock(&wakelocks_lock);
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wl = wakelock_lookup_add(buf, len, false);
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if (IS_ERR(wl)) {
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ret = PTR_ERR(wl);
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goto out;
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}
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__pm_relax(wl->ws);
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wakelocks_lru_most_recent(wl);
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wakelocks_gc();
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out:
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mutex_unlock(&wakelocks_lock);
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return ret;
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}
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