[PATCH 06/11] PM: Add user-space wake lock api.

Arve Hjønnevåg
2009-01-14T01:27:51Z

This adds /sys/power/wake_lock and /sys/power/wake_unlock.
Writing a string to wake_lock creates a wake lock the
first time is sees a string and locks it. Optionally, the
string can be followed by a timeout.
To unlock the wake lock, write the same string to wake_unlock.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
---
kernel/power/Kconfig | 10 ++
kernel/power/Makefile | 1 +
kernel/power/main.c | 9 ++
kernel/power/power.h | 11 ++
kernel/power/userwakelock.c | 218 +++++++++++++++++++++++++++++++++++++++++++
5 files changed, 249 insertions(+), 0 deletions(-)
create mode 100644 kernel/power/userwakelock.c

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 50690d8..dd6910d 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -138,6 +138,16 @@ config WAKELOCK_STAT
---help---
Report wake lock stats in /proc/wakelocks

+config USER_WAKELOCK
+ bool "Userspace wake locks"
+ depends on WAKELOCK
+ default y
+ ---help---
+ User-space wake lock api. Write "lockname" or "lockname timeout"
+ to /sys/power/wake_lock lock and if needed create a wake lock.
+ Write "lockname" to /sys/power/wake_unlock to unlock a user wake
+ lock.
+
config EARLYSUSPEND
bool "Early suspend"
depends on WAKELOCK
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index f0f7b15..4d838cd 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -6,6 +6,7 @@ endif
obj-y := main.o
obj-$(CONFIG_PM_SLEEP) += process.o console.o
obj-$(CONFIG_WAKELOCK) += wakelock.o
+obj-$(CONFIG_USER_WAKELOCK) += userwakelock.o
obj-$(CONFIG_EARLYSUSPEND) += earlysuspend.o
obj-$(CONFIG_HIBERNATION) += swsusp.o disk.o snapshot.o swap.o user.o

diff --git a/kernel/power/main.c b/kernel/power/main.c
index f2139ca..587f881 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -575,6 +575,11 @@ pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
power_attr(pm_trace);
#endif /* CONFIG_PM_TRACE */

+#ifdef CONFIG_USER_WAKELOCK
+power_attr(wake_lock);
+power_attr(wake_unlock);
+#endif
+
static struct attribute * g[] = {
&state_attr.attr,
#ifdef CONFIG_PM_TRACE
@@ -583,6 +588,10 @@ static struct attribute * g[] = {
#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
&pm_test_attr.attr,
#endif
+#ifdef CONFIG_USER_WAKELOCK
+ &wake_lock_attr.attr,
+ &wake_unlock_attr.attr,
+#endif
NULL,
};

diff --git a/kernel/power/power.h b/kernel/power/power.h
index 7ce9637..d1b19fc 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -231,6 +231,17 @@ extern struct wake_lock main_wake_lock;
extern suspend_state_t requested_suspend_state;
#endif

+#ifdef CONFIG_USER_WAKELOCK
+ssize_t wake_lock_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf);
+ssize_t wake_lock_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t n);
+ssize_t wake_unlock_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf);
+ssize_t wake_unlock_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t n);
+#endif
+
#ifdef CONFIG_EARLYSUSPEND
/* kernel/power/earlysuspend.c */
void request_suspend_state(suspend_state_t state);
diff --git a/kernel/power/userwakelock.c b/kernel/power/userwakelock.c
new file mode 100644
index 0000000..d7242d9
--- /dev/null
+++ b/kernel/power/userwakelock.c
@@ -0,0 +1,218 @@
+/* kernel/power/userwakelock.c
+ *
+ * Copyright (C) 2005-2008 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/ctype.h>
+#include <linux/module.h>
+#include <linux/wakelock.h>
+
+#include "power.h"
+
+enum {
+ DEBUG_FAILURE = BIT(0),
+ DEBUG_ERROR = BIT(1),
+ DEBUG_NEW = BIT(2),
+ DEBUG_ACCESS = BIT(3),
+ DEBUG_LOOKUP = BIT(4),
+};
+static int debug_mask = DEBUG_FAILURE;
+module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);
+
+static DEFINE_MUTEX(tree_lock);
+
+struct user_wake_lock {
+ struct rb_node node;
+ struct wake_lock wake_lock;
+ char name[0];
+};
+struct rb_root user_wake_locks;
+
+static struct user_wake_lock *lookup_wake_lock_name(
+ const char *buf, int allocate, long *timeoutptr)
+{
+ struct rb_node **p = &user_wake_locks.rb_node;
+ struct rb_node *parent = NULL;
+ struct user_wake_lock *l;
+ int diff;
+ u64 timeout;
+ int name_len;
+ const char *arg;
+
+ /* Find length of lock name and start of optional timeout string */
+ arg = buf;
+ while (*arg && !isspace(*arg))
+ arg++;
+ name_len = arg - buf;
+ if (!name_len)
+ goto bad_arg;
+ while (isspace(*arg))
+ arg++;
+
+ /* Process timeout string */
+ if (timeoutptr && *arg) {
+ timeout = simple_strtoull(arg, (char **)&arg, 0);
+ while (isspace(*arg))
+ arg++;
+ if (*arg)
+ goto bad_arg;
+ /* convert timeout from nanoseconds to jiffies > 0 */
+ timeout += (NSEC_PER_SEC / HZ) - 1;
+ do_div(timeout, (NSEC_PER_SEC / HZ));
+ if (timeout <= 0)
+ timeout = 1;
+ *timeoutptr = timeout;
+ } else if (*arg)
+ goto bad_arg;
+ else if (timeoutptr)
+ *timeoutptr = 0;
+
+ /* Lookup wake lock in rbtree */
+ while (*p) {
+ parent = *p;
+ l = rb_entry(parent, struct user_wake_lock, node);
+ diff = strncmp(buf, l->name, name_len);
+ if (!diff && l->name[name_len])
+ diff = -1;
+ if (debug_mask & DEBUG_ERROR)
+ pr_info("lookup_wake_lock_name: compare %.*s %s %d\n",
+ name_len, buf, l->name, diff);
+
+ if (diff < 0)
+ p = &(*p)->rb_left;
+ else if (diff > 0)
+ p = &(*p)->rb_right;
+ else
+ return l;
+ }
+
+ /* Allocate and add new wakelock to rbtree */
+ if (!allocate) {
+ if (debug_mask & DEBUG_ERROR)
+ pr_info("lookup_wake_lock_name: %.*s not found\n",
+ name_len, buf);
+ return ERR_PTR(-EINVAL);
+ }
+ l = kzalloc(sizeof(*l) + name_len + 1, GFP_KERNEL);
+ if (l == NULL) {
+ if (debug_mask & DEBUG_FAILURE)
+ pr_err("lookup_wake_lock_name: failed to allocate "
+ "memory for %.*s\n", name_len, buf);
+ return ERR_PTR(-ENOMEM);
+ }
+ memcpy(l->name, buf, name_len);
+ if (debug_mask & DEBUG_NEW)
+ pr_info("lookup_wake_lock_name: new wake lock %s\n", l->name);
+ wake_lock_init(&l->wake_lock, WAKE_LOCK_SUSPEND, l->name);
+ rb_link_node(&l->node, parent, p);
+ rb_insert_color(&l->node, &user_wake_locks);
+ return l;
+
+bad_arg:
+ if (debug_mask & DEBUG_ERROR)
+ pr_info("lookup_wake_lock_name: wake lock, %.*s, bad arg, %s\n",
+ name_len, buf, arg);
+ return ERR_PTR(-EINVAL);
+}
+
+ssize_t wake_lock_show(
+ struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ char *s = buf;
+ char *end = buf + PAGE_SIZE;
+ struct rb_node *n;
+ struct user_wake_lock *l;
+
+ mutex_lock(&tree_lock);
+
+ for (n = rb_first(&user_wake_locks); n != NULL; n = rb_next(n)) {
+ l = rb_entry(n, struct user_wake_lock, node);
+ if (wake_lock_active(&l->wake_lock))
+ s += scnprintf(s, end - s, "%s ", l->name);
+ }
+ s += scnprintf(s, end - s, "\n");
+
+ mutex_unlock(&tree_lock);
+ return (s - buf);
+}
+
+ssize_t wake_lock_store(
+ struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ long timeout;
+ struct user_wake_lock *l;
+
+ mutex_lock(&tree_lock);
+ l = lookup_wake_lock_name(buf, 1, &timeout);
+ if (IS_ERR(l)) {
+ n = PTR_ERR(l);
+ goto bad_name;
+ }
+
+ if (debug_mask & DEBUG_ACCESS)
+ pr_info("wake_lock_store: %s, timeout %ld\n", l->name, timeout);
+
+ if (timeout)
+ wake_lock_timeout(&l->wake_lock, timeout);
+ else
+ wake_lock(&l->wake_lock);
+bad_name:
+ mutex_unlock(&tree_lock);
+ return n;
+}
+
+
+ssize_t wake_unlock_show(
+ struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ char *s = buf;
+ char *end = buf + PAGE_SIZE;
+ struct rb_node *n;
+ struct user_wake_lock *l;
+
+ mutex_lock(&tree_lock);
+
+ for (n = rb_first(&user_wake_locks); n != NULL; n = rb_next(n)) {
+ l = rb_entry(n, struct user_wake_lock, node);
+ if (!wake_lock_active(&l->wake_lock))
+ s += scnprintf(s, end - s, "%s ", l->name);
+ }
+ s += scnprintf(s, end - s, "\n");
+
+ mutex_unlock(&tree_lock);
+ return (s - buf);
+}
+
+ssize_t wake_unlock_store(
+ struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ struct user_wake_lock *l;
+
+ mutex_lock(&tree_lock);
+ l = lookup_wake_lock_name(buf, 0, NULL);
+ if (IS_ERR(l)) {
+ n = PTR_ERR(l);
+ goto not_found;
+ }
+
+ if (debug_mask & DEBUG_ACCESS)
+ pr_info("wake_unlock_store: %s\n", l->name);
+
+ wake_unlock(&l->wake_lock);
+not_found:
+ mutex_unlock(&tree_lock);
+ return n;
+}
+
--
1.6.1

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