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/*
* pm.c - Power management interface
*
* Copyright (C) 2000 Andrew Henroid
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/pm.h>
int pm_active = 0;
static spinlock_t pm_devs_lock = SPIN_LOCK_UNLOCKED;
static LIST_HEAD(pm_devs);
/*
* Register a device with power management
*/
struct pm_dev *pm_register(pm_dev_t type,
unsigned long id,
pm_callback callback)
{
struct pm_dev *dev = kmalloc(sizeof(struct pm_dev), GFP_KERNEL);
if (dev) {
unsigned long flags;
memset(dev, 0, sizeof(*dev));
dev->type = type;
dev->id = id;
dev->callback = callback;
spin_lock_irqsave(&pm_devs_lock, flags);
list_add(&dev->entry, &pm_devs);
spin_unlock_irqrestore(&pm_devs_lock, flags);
}
return dev;
}
/*
* Unregister a device with power management
*/
void pm_unregister(struct pm_dev *dev)
{
if (dev) {
unsigned long flags;
spin_lock_irqsave(&pm_devs_lock, flags);
list_del(&dev->entry);
spin_unlock_irqrestore(&pm_devs_lock, flags);
kfree(dev);
}
}
/*
* Unregister all devices with matching callback
*/
void pm_unregister_all(pm_callback callback)
{
struct list_head *entry;
if (!callback)
return;
entry = pm_devs.next;
while (entry != &pm_devs) {
struct pm_dev *dev = list_entry(entry, struct pm_dev, entry);
entry = entry->next;
if (dev->callback == callback)
pm_unregister(dev);
}
}
/*
* Send request to a single device
*/
int pm_send(struct pm_dev *dev, pm_request_t rqst, void *data)
{
int status = 0;
int prev_state, next_state;
switch (rqst) {
case PM_SUSPEND:
case PM_RESUME:
prev_state = dev->state;
next_state = (int) data;
if (prev_state != next_state) {
if (dev->callback)
status = (*dev->callback)(dev, rqst, data);
if (!status) {
dev->state = next_state;
dev->prev_state = prev_state;
}
}
else {
dev->prev_state = prev_state;
}
break;
default:
if (dev->callback)
status = (*dev->callback)(dev, rqst, data);
break;
}
return status;
}
/*
* Undo incomplete request
*/
static void pm_undo_all(struct pm_dev *last)
{
struct list_head *entry = last->entry.prev;
while (entry != &pm_devs) {
struct pm_dev *dev = list_entry(entry, struct pm_dev, entry);
if (dev->state != dev->prev_state) {
/* previous state was zero (running) resume or
* previous state was non-zero (suspended) suspend
*/
pm_request_t undo = (dev->prev_state
? PM_SUSPEND:PM_RESUME);
pm_send(dev, undo, (void*) dev->prev_state);
}
entry = entry->prev;
}
}
/*
* Send a request to all devices
*/
int pm_send_all(pm_request_t rqst, void *data)
{
struct list_head *entry = pm_devs.next;
while (entry != &pm_devs) {
struct pm_dev *dev = list_entry(entry, struct pm_dev, entry);
if (dev->callback) {
int status = pm_send(dev, rqst, data);
if (status) {
/* return devices to previous state on
* failed suspend request
*/
if (rqst == PM_SUSPEND)
pm_undo_all(dev);
return status;
}
}
entry = entry->next;
}
return 0;
}
/*
* Find a device
*/
struct pm_dev *pm_find(pm_dev_t type, struct pm_dev *from)
{
struct list_head *entry = from ? from->entry.next:pm_devs.next;
while (entry != &pm_devs) {
struct pm_dev *dev = list_entry(entry, struct pm_dev, entry);
if (type == PM_UNKNOWN_DEV || dev->type == type)
return dev;
entry = entry->next;
}
return 0;
}
EXPORT_SYMBOL(pm_register);
EXPORT_SYMBOL(pm_unregister);
EXPORT_SYMBOL(pm_unregister_all);
EXPORT_SYMBOL(pm_send);
EXPORT_SYMBOL(pm_send_all);
EXPORT_SYMBOL(pm_find);
EXPORT_SYMBOL(pm_active);
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