1 files changed, 259 insertions, 0 deletions

diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
new file mode 100644
index 000000000000..c8fba3380076
--- /dev/null
+++ b/kernel/power/wakelock.c
@@ -0,0 +1,259 @@
+/*
+ * 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>
+
+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;
+
+        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;
+
+        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;
+}