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/*
* suspend.c - Functions for putting devices to sleep.
*
* Copyright (c) 2003 Patrick Mochel
* Copyright (c) 2003 Open Source Development Labs
*
* This file is released under the GPLv2
*
*/
#include <linux/device.h>
#include <linux/kallsyms.h>
#include <linux/pm.h>
#include "../base.h"
#include "power.h"
/*
* The entries in the dpm_active list are in a depth first order, simply
* because children are guaranteed to be discovered after parents, and
* are inserted at the back of the list on discovery.
*
* All list on the suspend path are done in reverse order, so we operate
* on the leaves of the device tree (or forests, depending on how you want
* to look at it ;) first. As nodes are removed from the back of the list,
* they are inserted into the front of their destintation lists.
*
* Things are the reverse on the resume path - iterations are done in
* forward order, and nodes are inserted at the back of their destination
* lists. This way, the ancestors will be accessed before their descendents.
*/
static inline char *suspend_verb(u32 event)
{
switch (event) {
case PM_EVENT_SUSPEND: return "suspend";
case PM_EVENT_FREEZE: return "freeze";
default: return "(unknown suspend event)";
}
}
/**
* suspend_device - Save state of one device.
* @dev: Device.
* @state: Power state device is entering.
*/
int suspend_device(struct device * dev, pm_message_t state)
{
int error = 0;
down(&dev->sem);
if (dev->power.power_state.event) {
dev_dbg(dev, "PM: suspend %d-->%d\n",
dev->power.power_state.event, state.event);
}
if (dev->power.pm_parent
&& dev->power.pm_parent->power.power_state.event) {
dev_err(dev,
"PM: suspend %d->%d, parent %s already %d\n",
dev->power.power_state.event, state.event,
dev->power.pm_parent->bus_id,
dev->power.pm_parent->power.power_state.event);
}
dev->power.prev_state = dev->power.power_state;
if (dev->class && dev->class->suspend && !dev->power.power_state.event) {
dev_dbg(dev, "class %s%s\n",
suspend_verb(state.event),
((state.event == PM_EVENT_SUSPEND)
&& device_may_wakeup(dev))
? ", may wakeup"
: ""
);
error = dev->class->suspend(dev, state);
suspend_report_result(dev->class->suspend, error);
}
if (!error && dev->bus && dev->bus->suspend && !dev->power.power_state.event) {
dev_dbg(dev, "%s%s\n",
suspend_verb(state.event),
((state.event == PM_EVENT_SUSPEND)
&& device_may_wakeup(dev))
? ", may wakeup"
: ""
);
error = dev->bus->suspend(dev, state);
suspend_report_result(dev->bus->suspend, error);
}
up(&dev->sem);
return error;
}
/*
* This is called with interrupts off, only a single CPU
* running. We can't do down() on a semaphore (and we don't
* need the protection)
*/
static int suspend_device_late(struct device *dev, pm_message_t state)
{
int error = 0;
if (dev->power.power_state.event) {
dev_dbg(dev, "PM: suspend_late %d-->%d\n",
dev->power.power_state.event, state.event);
}
if (dev->bus && dev->bus->suspend_late && !dev->power.power_state.event) {
dev_dbg(dev, "LATE %s%s\n",
suspend_verb(state.event),
((state.event == PM_EVENT_SUSPEND)
&& device_may_wakeup(dev))
? ", may wakeup"
: ""
);
error = dev->bus->suspend_late(dev, state);
suspend_report_result(dev->bus->suspend_late, error);
}
return error;
}
/**
* device_prepare_suspend - save state and prepare to suspend
*
* NOTE! Devices cannot detach at this point - not only do we
* hold the device list semaphores over the whole prepare, but
* the whole point is to do non-invasive preparatory work, not
* the actual suspend.
*/
int device_prepare_suspend(pm_message_t state)
{
int error = 0;
struct device * dev;
down(&dpm_sem);
down(&dpm_list_sem);
list_for_each_entry_reverse(dev, &dpm_active, power.entry) {
if (!dev->bus || !dev->bus->suspend_prepare)
continue;
error = dev->bus->suspend_prepare(dev, state);
if (error)
break;
}
up(&dpm_list_sem);
up(&dpm_sem);
return error;
}
/**
* device_suspend - Save state and stop all devices in system.
* @state: Power state to put each device in.
*
* Walk the dpm_active list, call ->suspend() for each device, and move
* it to the dpm_off list.
*
* (For historical reasons, if it returns -EAGAIN, that used to mean
* that the device would be called again with interrupts disabled.
* These days, we use the "suspend_late()" callback for that, so we
* print a warning and consider it an error).
*
* If we get a different error, try and back out.
*
* If we hit a failure with any of the devices, call device_resume()
* above to bring the suspended devices back to life.
*
*/
int device_suspend(pm_message_t state)
{
int error = 0;
down(&dpm_sem);
down(&dpm_list_sem);
while (!list_empty(&dpm_active) && error == 0) {
struct list_head * entry = dpm_active.prev;
struct device * dev = to_device(entry);
get_device(dev);
up(&dpm_list_sem);
error = suspend_device(dev, state);
down(&dpm_list_sem);
/* Check if the device got removed */
if (!list_empty(&dev->power.entry)) {
/* Move it to the dpm_off list */
if (!error)
list_move(&dev->power.entry, &dpm_off);
}
if (error)
printk(KERN_ERR "Could not suspend device %s: "
"error %d%s\n",
kobject_name(&dev->kobj), error,
error == -EAGAIN ? " (please convert to suspend_late)" : "");
put_device(dev);
}
up(&dpm_list_sem);
if (error)
dpm_resume();
up(&dpm_sem);
return error;
}
EXPORT_SYMBOL_GPL(device_suspend);
/**
* device_power_down - Shut down special devices.
* @state: Power state to enter.
*
* Walk the dpm_off_irq list, calling ->power_down() for each device that
* couldn't power down the device with interrupts enabled. When we're
* done, power down system devices.
*/
int device_power_down(pm_message_t state)
{
int error = 0;
struct device * dev;
while (!list_empty(&dpm_off)) {
struct list_head * entry = dpm_off.prev;
dev = to_device(entry);
error = suspend_device_late(dev, state);
if (error)
goto Error;
list_move(&dev->power.entry, &dpm_off_irq);
}
error = sysdev_suspend(state);
Done:
return error;
Error:
printk(KERN_ERR "Could not power down device %s: "
"error %d\n", kobject_name(&dev->kobj), error);
dpm_power_up();
goto Done;
}
EXPORT_SYMBOL_GPL(device_power_down);
void __suspend_report_result(const char *function, void *fn, int ret)
{
if (ret) {
printk(KERN_ERR "%s(): ", function);
print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
printk("%d\n", ret);
}
}
EXPORT_SYMBOL_GPL(__suspend_report_result);
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