Reading from this file causes the last string successfully
written to it to be returned.
+
+What: /sys/power/wake_lock
+Date: February 2012
+Contact: Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+ The /sys/power/wake_lock file allows user space to create
+ wakeup source objects and activate them on demand (if one of
+ those wakeup sources is active, reads from the
+ /sys/power/wakeup_count file block or return false). When a
+ string without white space is written to /sys/power/wake_lock,
+ it will be assumed to represent a wakeup source name. If there
+ is a wakeup source object with that name, it will be activated
+ (unless active already). Otherwise, a new wakeup source object
+ will be registered, assigned the given name and activated.
+ If a string written to /sys/power/wake_lock contains white
+ space, the part of the string preceding the white space will be
+ regarded as a wakeup source name and handled as descrived above.
+ The other part of the string will be regarded as a timeout (in
+ nanoseconds) such that the wakeup source will be automatically
+ deactivated after it has expired. The timeout, if present, is
+ set regardless of the current state of the wakeup source object
+ in question.
+
+ Reads from this file return a string consisting of the names of
+ wakeup sources created with the help of it that are active at
+ the moment, separated with spaces.
+
+
+What: /sys/power/wake_unlock
+Date: February 2012
+Contact: Rafael J. Wysocki <rjw@sisk.pl>
+Description:
+ The /sys/power/wake_unlock file allows user space to deactivate
+ wakeup sources created with the help of /sys/power/wake_lock.
+ When a string is written to /sys/power/wake_unlock, it will be
+ assumed to represent the name of a wakeup source to deactivate.
+ If a wakeup source object of that name exists and is active at
+ the moment, it will be deactivated.
+
+ Reads from this file return a string consisting of the names of
+ wakeup sources created with the help of /sys/power/wake_lock
+ that are inactive at the moment, separated with spaces.
power_attr(autosleep);
#endif /* CONFIG_PM_AUTOSLEEP */
+
+#ifdef CONFIG_PM_WAKELOCKS
+static ssize_t wake_lock_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return pm_show_wakelocks(buf, true);
+}
+
+static ssize_t wake_lock_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ int error = pm_wake_lock(buf);
+ return error ? error : n;
+}
+
+power_attr(wake_lock);
+
+static ssize_t wake_unlock_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return pm_show_wakelocks(buf, false);
+}
+
+static ssize_t wake_unlock_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ int error = pm_wake_unlock(buf);
+ return error ? error : n;
+}
+
+power_attr(wake_unlock);
+
+#endif /* CONFIG_PM_WAKELOCKS */
#endif /* CONFIG_PM_SLEEP */
#ifdef CONFIG_PM_TRACE
#ifdef CONFIG_PM_AUTOSLEEP
&autosleep_attr.attr,
#endif
+#ifdef CONFIG_PM_WAKELOCKS
+ &wake_lock_attr.attr,
+ &wake_unlock_attr.attr,
+#endif
#ifdef CONFIG_PM_DEBUG
&pm_test_attr.attr,
#endif
--- /dev/null
+/*
+ * 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/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>
+
+#define WL_NUMBER_LIMIT 100
+#define WL_GC_COUNT_MAX 100
+#define WL_GC_TIME_SEC 300
+
+static DEFINE_MUTEX(wakelocks_lock);
+
+struct wakelock {
+ char *name;
+ struct rb_node node;
+ struct wakeup_source ws;
+ struct list_head lru;
+};
+
+static struct rb_root wakelocks_tree = RB_ROOT;
+static LIST_HEAD(wakelocks_lru_list);
+static unsigned int number_of_wakelocks;
+static unsigned int wakelocks_gc_count;
+
+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);
+}
+
+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 (number_of_wakelocks > WL_NUMBER_LIMIT)
+ 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);
+ list_add(&wl->lru, &wakelocks_lru_list);
+ number_of_wakelocks++;
+ 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;
+
+ 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);
+ }
+
+ list_move(&wl->lru, &wakelocks_lru_list);
+
+ out:
+ mutex_unlock(&wakelocks_lock);
+ return ret;
+}
+
+static void wakelocks_gc(void)
+{
+ struct wakelock *wl, *aux;
+ ktime_t 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);
+ number_of_wakelocks--;
+ }
+ }
+ wakelocks_gc_count = 0;
+}
+
+int pm_wake_unlock(const char *buf)
+{
+ struct wakelock *wl;
+ size_t len;
+ int ret = 0;
+
+ 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);
+ list_move(&wl->lru, &wakelocks_lru_list);
+ if (++wakelocks_gc_count > WL_GC_COUNT_MAX)
+ wakelocks_gc();
+
+ out:
+ mutex_unlock(&wakelocks_lock);
+ return ret;
+}
projects / ceph-client.git / commitdiff