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

/*
 * 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);

static DEFINE_MUTEX(dpm_list_mtx);
static pm_message_t pm_transition;

/*
 * Set once the preparation of devices for a PM transition has started, reset
 * before starting to resume devices.  Protected by dpm_list_mtx.
 */
static bool transition_started;

/**
 * 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.status = DPM_ON;
	init_completion(&dev->power.completion);
	pm_runtime_init(dev);
}

/**
 * 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",
		 kobject_name(&dev->kobj));
	mutex_lock(&dpm_list_mtx);
	if (dev->parent) {
		if (dev->parent->power.status >= DPM_SUSPENDING)
			dev_warn(dev, "parent %s should not be sleeping\n",
				 dev_name(dev->parent));
	} else if (transition_started) {
		/*
		 * We refuse to register parentless devices while a PM
		 * transition is in progress in order to avoid leaving them
		 * unhandled down the road
		 */
		dev_WARN(dev, "Parentless device registered during a PM transaction\n");
	}

	list_add_tail(&dev->power.entry, &dpm_list);
	mutex_unlock(&dpm_list_mtx);
}

/**
 * device_pm_remove - Remove a device from the PM core's list of active devices.
 * @dev: Device to be removed from the list.
 */
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));
	complete_all(&dev->power.completion);
	mutex_lock(&dpm_list_mtx);
	list_del_init(&dev->power.entry);
	mutex_unlock(&dpm_list_mtx);
	pm_runtime_remove(dev);
}

/**
 * device_pm_move_before - Move device in the PM core's list of active devices.
 * @deva: Device to move in dpm_list.
 * @devb: Device @deva should come before.
 */
void device_pm_move_before(struct device *deva, struct device *devb)
{
	pr_debug("PM: Moving %s:%s before %s:%s\n",
		 deva->bus ? deva->bus->name : "No Bus",
		 kobject_name(&deva->kobj),
		 devb->bus ? devb->bus->name : "No Bus",
		 kobject_name(&devb->kobj));
	/* Delete deva from dpm_list and reinsert before devb. */
	list_move_tail(&deva->power.entry, &devb->power.entry);
}

/**
 * device_pm_move_after - Move device in the PM core's list of active devices.
 * @deva: Device to move in dpm_list.
 * @devb: Device @deva should come after.
 */
void device_pm_move_after(struct device *deva, struct device *devb)
{
	pr_debug("PM: Moving %s:%s after %s:%s\n",
		 deva->bus ? deva->bus->name : "No Bus",
		 kobject_name(&deva->kobj),
		 devb->bus ? devb->bus->name : "No Bus",
		 kobject_name(&devb->kobj));
	/* Delete deva from dpm_list and reinsert after devb. */
	list_move(&deva->power.entry, &devb->power.entry);
}

/**
 * device_pm_move_last - Move device to end of the PM core's list of devices.
 * @dev: Device to move in dpm_list.
 */
void device_pm_move_last(struct device *dev)
{
	pr_debug("PM: Moving %s:%s to end of list\n",
		 dev->bus ? dev->bus->name : "No Bus",
		 kobject_name(&dev->kobj));
	list_move_tail(&dev->power.entry, &dpm_list);
}

static ktime_t initcall_debug_start(