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/* kernel/power/fbearlysuspend.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/earlysuspend.h>
#include <linux/module.h>
#include <linux/wait.h>
#include "power.h"
static wait_queue_head_t fb_state_wq;
static DEFINE_SPINLOCK(fb_state_lock);
static enum {
FB_STATE_STOPPED_DRAWING,
FB_STATE_REQUEST_STOP_DRAWING,
FB_STATE_DRAWING_OK,
} fb_state;
/* tell userspace to stop drawing, wait for it to stop */
static void stop_drawing_early_suspend(struct early_suspend *h)
{
int ret;
unsigned long irq_flags;
spin_lock_irqsave(&fb_state_lock, irq_flags);
fb_state = FB_STATE_REQUEST_STOP_DRAWING;
spin_unlock_irqrestore(&fb_state_lock, irq_flags);
wake_up_all(&fb_state_wq);
ret = wait_event_timeout(fb_state_wq,
fb_state == FB_STATE_STOPPED_DRAWING,
HZ);
if (unlikely(fb_state != FB_STATE_STOPPED_DRAWING))
pr_warning("stop_drawing_early_suspend: timeout waiting for "
"userspace to stop drawing\n");
}
/* tell userspace to start drawing */
static void start_drawing_late_resume(struct early_suspend *h)
{
unsigned long irq_flags;
spin_lock_irqsave(&fb_state_lock, irq_flags);
fb_state = FB_STATE_DRAWING_OK;
spin_unlock_irqrestore(&fb_state_lock, irq_flags);
wake_up(&fb_state_wq);
}
static struct early_suspend stop_drawing_early_suspend_desc = {
.level = EARLY_SUSPEND_LEVEL_STOP_DRAWING,
.suspend = stop_drawing_early_suspend,
.resume = start_drawing_late_resume,
};
static ssize_t wait_for_fb_sleep_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
char *s = buf;
int ret;
ret = wait_event_interruptible(fb_state_wq,
fb_state != FB_STATE_DRAWING_OK);
if (ret && fb_state == FB_STATE_DRAWING_OK)
return ret;
else
s += sprintf(buf, "sleeping");
return s - buf;
}
static ssize_t wait_for_fb_wake_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
char *s = buf;
int ret;
unsigned long irq_flags;
spin_lock_irqsave(&fb_state_lock, irq_flags);
if (fb_state == FB_STATE_REQUEST_STOP_DRAWING) {
fb_state = FB_STATE_STOPPED_DRAWING;
wake_up(&fb_state_wq);
}
spin_unlock_irqrestore(&fb_state_lock, irq_flags);
ret = wait_event_interruptible(fb_state_wq,
fb_state == FB_STATE_DRAWING_OK);
if (ret && fb_state != FB_STATE_DRAWING_OK)
return ret;
else
s += sprintf(buf, "awake");
return s - buf;
}
#define power_ro_attr(_name) \
static struct kobj_attribute _name##_attr = { \
.attr = { \
.name = __stringify(_name), \
.mode = 0444, \
}, \
.show = _name##_show, \
.store = NULL, \
}
power_ro_attr(wait_for_fb_sleep);
power_ro_attr(wait_for_fb_wake);
static struct attribute *g[] = {
&wait_for_fb_sleep_attr.attr,
&wait_for_fb_wake_attr.attr,
NULL,
};
static struct attribute_group attr_group = {
.attrs = g,
};
static int __init android_power_init(void)
{
int ret;
init_waitqueue_head(&fb_state_wq);
fb_state = FB_STATE_DRAWING_OK;
ret = sysfs_create_group(power_kobj, &attr_group);
if (ret) {
pr_err("android_power_init: sysfs_create_group failed\n");
return ret;
}
register_early_suspend(&stop_drawing_early_suspend_desc);
return 0;
}
static void __exit android_power_exit(void)
{
unregister_early_suspend(&stop_drawing_early_suspend_desc);
sysfs_remove_group(power_kobj, &attr_group);
}
module_init(android_power_init);
module_exit(android_power_exit);
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