154 lines
3.7 KiB
C
154 lines
3.7 KiB
C
/* kernel/power/fbearlysuspend.c
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*
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* Copyright (C) 2005-2008 Google, Inc.
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/earlysuspend.h>
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#include <linux/module.h>
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#include <linux/wait.h>
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#include "power.h"
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static wait_queue_head_t fb_state_wq;
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static DEFINE_SPINLOCK(fb_state_lock);
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static enum {
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FB_STATE_STOPPED_DRAWING,
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FB_STATE_REQUEST_STOP_DRAWING,
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FB_STATE_DRAWING_OK,
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} fb_state;
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/* tell userspace to stop drawing, wait for it to stop */
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static void stop_drawing_early_suspend(struct early_suspend *h)
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{
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int ret;
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unsigned long irq_flags;
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spin_lock_irqsave(&fb_state_lock, irq_flags);
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fb_state = FB_STATE_REQUEST_STOP_DRAWING;
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spin_unlock_irqrestore(&fb_state_lock, irq_flags);
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wake_up_all(&fb_state_wq);
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ret = wait_event_timeout(fb_state_wq,
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fb_state == FB_STATE_STOPPED_DRAWING,
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HZ);
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if (unlikely(fb_state != FB_STATE_STOPPED_DRAWING))
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pr_warning("stop_drawing_early_suspend: timeout waiting for "
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"userspace to stop drawing\n");
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}
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/* tell userspace to start drawing */
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void start_drawing_late_resume(struct early_suspend *h)
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{
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unsigned long irq_flags;
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spin_lock_irqsave(&fb_state_lock, irq_flags);
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fb_state = FB_STATE_DRAWING_OK;
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spin_unlock_irqrestore(&fb_state_lock, irq_flags);
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wake_up(&fb_state_wq);
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}
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static struct early_suspend stop_drawing_early_suspend_desc = {
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.level = EARLY_SUSPEND_LEVEL_STOP_DRAWING,
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.suspend = stop_drawing_early_suspend,
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.resume = NULL,
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};
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static ssize_t wait_for_fb_sleep_show(struct kobject *kobj,
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struct kobj_attribute *attr, char *buf)
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{
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char *s = buf;
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int ret;
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ret = wait_event_interruptible(fb_state_wq,
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fb_state != FB_STATE_DRAWING_OK);
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if (ret && fb_state == FB_STATE_DRAWING_OK)
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return ret;
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else
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s += sprintf(buf, "sleeping");
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return s - buf;
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}
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static ssize_t wait_for_fb_wake_show(struct kobject *kobj,
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struct kobj_attribute *attr, char *buf)
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{
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char *s = buf;
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int ret;
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unsigned long irq_flags;
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spin_lock_irqsave(&fb_state_lock, irq_flags);
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if (fb_state == FB_STATE_REQUEST_STOP_DRAWING) {
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fb_state = FB_STATE_STOPPED_DRAWING;
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wake_up(&fb_state_wq);
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}
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spin_unlock_irqrestore(&fb_state_lock, irq_flags);
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ret = wait_event_interruptible(fb_state_wq,
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fb_state == FB_STATE_DRAWING_OK);
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if (ret && fb_state != FB_STATE_DRAWING_OK)
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return ret;
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else
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s += sprintf(buf, "awake");
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return s - buf;
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}
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#define power_ro_attr(_name) \
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static struct kobj_attribute _name##_attr = { \
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.attr = { \
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.name = __stringify(_name), \
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.mode = 0444, \
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}, \
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.show = _name##_show, \
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.store = NULL, \
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}
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power_ro_attr(wait_for_fb_sleep);
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power_ro_attr(wait_for_fb_wake);
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static struct attribute *g[] = {
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&wait_for_fb_sleep_attr.attr,
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&wait_for_fb_wake_attr.attr,
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NULL,
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};
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static struct attribute_group attr_group = {
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.attrs = g,
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};
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static int __init android_power_init(void)
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{
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int ret;
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init_waitqueue_head(&fb_state_wq);
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fb_state = FB_STATE_DRAWING_OK;
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ret = sysfs_create_group(power_kobj, &attr_group);
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if (ret) {
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pr_err("android_power_init: sysfs_create_group failed\n");
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return ret;
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}
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register_early_suspend(&stop_drawing_early_suspend_desc);
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return 0;
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}
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static void __exit android_power_exit(void)
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{
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unregister_early_suspend(&stop_drawing_early_suspend_desc);
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sysfs_remove_group(power_kobj, &attr_group);
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}
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module_init(android_power_init);
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module_exit(android_power_exit);
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