path: root/drivers/base/power/main.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 initialize 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 separate list is used for keeping track of power info, because the power
 * domain dependencies may differ from the ancestral dependencies that the
 * subsystem list maintains.
 */

#include <linux/device.h>
#include <linux/kallsyms.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/resume-trace.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/async.h>
#include <linux/suspend.h>

#include "../base.h"
#include "power.h"

typedef int (*pm_callback_t)(struct device *);

/*
 * The entries in the dpm_list 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.
 *
 * Since device_pm_add() may be called with a device lock held,
 * we must never try to acquire a device lock while holding
 * dpm_list_mutex.
 */

LIST_HEAD(dpm_list);
LIST_HEAD(dpm_prepared_list);
LIST_HEAD(dpm_suspended_list);
LIST_HEAD(dpm_late_early_list);
LIST_HEAD(dpm_noirq_list);

struct suspend_stats suspend_stats;
static DEFINE_MUTEX(dpm_list_mtx);
static pm_message_t pm_transition;

static int async_error;

/**
 * device_pm_init - Initialize the PM-related part of a device object.
 * @dev: Device object being initialized.
 */
void device_pm_init(struct device *dev)
{
	dev->power.is_prepared = false;
	dev->power.is_suspended = false;
	init_completion(&dev->power.completion);
	complete_all(&dev->power.completion);
	dev->power.wakeup = NULL;
	spin_lock_init(&dev->power.lock);
	pm_runtime_init(dev);
	INIT_LIST_HEAD(&dev->power.entry);
	dev->power.power_state = PMSG_INVALID;
}

/**
 * device_pm_lock - Lock the list of active devices used by the PM core.
 */
void device_pm_lock(void)
{
	mutex_lock(&dpm_list_mtx);
}

/**
 * device_pm_unlock - Unlock the list of active devices used by the PM core.
 */
void device_pm_unlock(void)
{
	mutex_unlock(&dpm_list_mtx);
}

/**
 * device_pm_add - Add a device to the PM core's list of active devices.
 * @dev: Device to add to the list.
 */
void device_pm_add(struct device *dev)
{
	pr_debug("PM: Adding info for %s:%s\n",
		 dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
	mutex_lock(&dpm_list_mtx);
	if (dev->parent && dev->parent->power.is_prepared)
		dev_warn(dev, "parent %s should not be sleeping\n",
			dev_name(dev->parent));
	list_add_tail(&dev->power.entry, &dpm_list);
	dev_pm_qos_constraints_init(dev);
	mutex_unlock(&