WSL2-Linux-Kernel/drivers/base/power/main.c

400 строки
9.6 KiB
C

/*
* drivers/base/power/main.c - Where the driver meets power management.
*
* Copyright (c) 2003 Patrick Mochel
* Copyright (c) 2003 Open Source Development Lab
*
* This file is released under the GPLv2
*
*
* The driver model core calls device_pm_add() when a device is registered.
* This will intialize the embedded device_pm_info object in the device
* and add it to the list of power-controlled devices. sysfs entries for
* controlling device power management will also be added.
*
* A different set of lists than the global subsystem list are used to
* keep track of power info because we use different lists to hold
* devices based on what stage of the power management process they
* are in. The power domain dependencies may also differ from the
* ancestral dependencies that the subsystem list maintains.
*/
#include <linux/device.h>
#include <linux/kallsyms.h>
#include <linux/mutex.h>
#include <linux/pm.h>
#include <linux/resume-trace.h>
#include "../base.h"
#include "power.h"
LIST_HEAD(dpm_active);
static LIST_HEAD(dpm_off);
static LIST_HEAD(dpm_off_irq);
static DEFINE_MUTEX(dpm_mtx);
static DEFINE_MUTEX(dpm_list_mtx);
int (*platform_enable_wakeup)(struct device *dev, int is_on);
int device_pm_add(struct device *dev)
{
int error;
pr_debug("PM: Adding info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus",
kobject_name(&dev->kobj));
mutex_lock(&dpm_list_mtx);
list_add_tail(&dev->power.entry, &dpm_active);
error = dpm_sysfs_add(dev);
if (error)
list_del(&dev->power.entry);
mutex_unlock(&dpm_list_mtx);
return error;
}
void device_pm_remove(struct device *dev)
{
pr_debug("PM: Removing info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus",
kobject_name(&dev->kobj));
mutex_lock(&dpm_list_mtx);
dpm_sysfs_remove(dev);
list_del_init(&dev->power.entry);
mutex_unlock(&dpm_list_mtx);
}
/*------------------------- Resume routines -------------------------*/
/**
* resume_device - Restore state for one device.
* @dev: Device.
*
*/
static int resume_device(struct device * dev)
{
int error = 0;
TRACE_DEVICE(dev);
TRACE_RESUME(0);
down(&dev->sem);
if (dev->bus && dev->bus->resume) {
dev_dbg(dev,"resuming\n");
error = dev->bus->resume(dev);
}
if (!error && dev->type && dev->type->resume) {
dev_dbg(dev,"resuming\n");
error = dev->type->resume(dev);
}
if (!error && dev->class && dev->class->resume) {
dev_dbg(dev,"class resume\n");
error = dev->class->resume(dev);
}
up(&dev->sem);
TRACE_RESUME(error);
return error;
}
static int resume_device_early(struct device * dev)
{
int error = 0;
TRACE_DEVICE(dev);
TRACE_RESUME(0);
if (dev->bus && dev->bus->resume_early) {
dev_dbg(dev,"EARLY resume\n");
error = dev->bus->resume_early(dev);
}
TRACE_RESUME(error);
return error;
}
/*
* Resume the devices that have either not gone through
* the late suspend, or that did go through it but also
* went through the early resume
*/
static void dpm_resume(void)
{
mutex_lock(&dpm_list_mtx);
while(!list_empty(&dpm_off)) {
struct list_head * entry = dpm_off.next;
struct device * dev = to_device(entry);
get_device(dev);
list_move_tail(entry, &dpm_active);
mutex_unlock(&dpm_list_mtx);
resume_device(dev);
mutex_lock(&dpm_list_mtx);
put_device(dev);
}
mutex_unlock(&dpm_list_mtx);
}
/**
* device_resume - Restore state of each device in system.
*
* Walk the dpm_off list, remove each entry, resume the device,
* then add it to the dpm_active list.
*/
void device_resume(void)
{
might_sleep();
mutex_lock(&dpm_mtx);
dpm_resume();
mutex_unlock(&dpm_mtx);
}
EXPORT_SYMBOL_GPL(device_resume);
/**
* dpm_power_up - Power on some devices.
*
* Walk the dpm_off_irq list and power each device up. This
* is used for devices that required they be powered down with
* interrupts disabled. As devices are powered on, they are moved
* to the dpm_active list.
*
* Interrupts must be disabled when calling this.
*/
static void dpm_power_up(void)
{
while(!list_empty(&dpm_off_irq)) {
struct list_head * entry = dpm_off_irq.next;
struct device * dev = to_device(entry);
list_move_tail(entry, &dpm_off);
resume_device_early(dev);
}
}
/**
* device_power_up - Turn on all devices that need special attention.
*
* Power on system devices then devices that required we shut them down
* with interrupts disabled.
* Called with interrupts disabled.
*/
void device_power_up(void)
{
sysdev_resume();
dpm_power_up();
}
EXPORT_SYMBOL_GPL(device_power_up);
/*------------------------- Suspend routines -------------------------*/
/*
* 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";
case PM_EVENT_PRETHAW: return "prethaw";
default: return "(unknown suspend event)";
}
}
static void
suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
{
dev_dbg(dev, "%s%s%s\n", info, suspend_verb(state.event),
((state.event == PM_EVENT_SUSPEND) && device_may_wakeup(dev)) ?
", may wakeup" : "");
}
/**
* suspend_device - Save state of one device.
* @dev: Device.
* @state: Power state device is entering.
*/
static 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->class && dev->class->suspend) {
suspend_device_dbg(dev, state, "class ");
error = dev->class->suspend(dev, state);
suspend_report_result(dev->class->suspend, error);
}
if (!error && dev->type && dev->type->suspend) {
suspend_device_dbg(dev, state, "type ");
error = dev->type->suspend(dev, state);
suspend_report_result(dev->type->suspend, error);
}
if (!error && dev->bus && dev->bus->suspend) {
suspend_device_dbg(dev, state, "");
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 acquire a mutex or 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->bus && dev->bus->suspend_late) {
suspend_device_dbg(dev, state, "LATE ");
error = dev->bus->suspend_late(dev, state);
suspend_report_result(dev->bus->suspend_late, error);
}
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;
might_sleep();
mutex_lock(&dpm_mtx);
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_active) && error == 0) {
struct list_head * entry = dpm_active.prev;
struct device * dev = to_device(entry);
get_device(dev);
mutex_unlock(&dpm_list_mtx);
error = suspend_device(dev, state);
mutex_lock(&dpm_list_mtx);
/* 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);
}
mutex_unlock(&dpm_list_mtx);
if (error)
dpm_resume();
mutex_unlock(&dpm_mtx);
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);