path: root/drivers/base/power/domain.c

/*
 * drivers/base/power/domain.c - Common code related to device power domains.
 *
 * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
 *
 * This file is released under the GPLv2.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/pm_runtime.h>
#include <linux/pm_domain.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/suspend.h>

#ifdef CONFIG_PM

static struct generic_pm_domain *dev_to_genpd(struct device *dev)
{
	if (IS_ERR_OR_NULL(dev->pm_domain))
		return ERR_PTR(-EINVAL);

	return pd_to_genpd(dev->pm_domain);
}

static void genpd_sd_counter_dec(struct generic_pm_domain *genpd)
{
	if (!WARN_ON(genpd->sd_count == 0))
			genpd->sd_count--;
}

static void genpd_acquire_lock(struct generic_pm_domain *genpd)
{
	DEFINE_WAIT(wait);

	mutex_lock(&genpd->lock);
	/*
	 * Wait for the domain to transition into either the active,
	 * or the power off state.
	 */
	for (;;) {
		prepare_to_wait(&genpd->status_wait_queue, &wait,
				TASK_UNINTERRUPTIBLE);
		if (genpd->status != GPD_STATE_BUSY)
			break;
		mutex_unlock(&genpd->lock);

		schedule();

		mutex_lock(&genpd->lock);
	}
	finish_wait(&genpd->status_wait_queue, &wait);
}

static void genpd_release_lock(struct generic_pm_domain *genpd)
{
	mutex_unlock(&genpd->lock);
}

/**
 * pm_genpd_poweron - Restore power to a given PM domain and its parents.
 * @genpd: PM domain to power up.
 *
 * Restore power to @genpd and all of its parents so that it is possible to
 * resume a device belonging to it.
 */
int pm_genpd_poweron(struct generic_pm_domain *genpd)
{
	struct generic_pm_domain *parent = genpd->parent;
	DEFINE_WAIT(wait);
	int ret = 0;

 start:
	if (parent) {
		mutex_lock(&parent->lock);
		mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
	} else {
		mutex_lock(&genpd->lock);
	}
	/*
	 * Wait for the domain to transition into either the active,
	 * or the power off state.
	 */
	for (;;) {
		prepare_to_wait(&genpd->status_wait_queue, &wait,
				TASK_UNINTERRUPTIBLE);
		if (genpd->status != GPD_STATE_BUSY)
			break;
		mutex_unlock(&genpd->lock);
		if (parent)
			mutex_unlock(&parent->lock);

		schedule();

		if (parent) {
			mutex_lock(&parent->lock);
			mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
		} else {
			mutex_lock(&genpd->lock);
		}
	}
	finish_wait(&genpd->status_wait_queue, &wait);

	if (genpd->status == GPD_STATE_ACTIVE
	    || (genpd->prepared_count > 0 && genpd->suspend_power_off))
		goto out;

	if (parent && parent->status != GPD_STATE_ACTIVE) {
		mutex_unlock(&genpd->lock);
		mutex_unlock(&parent->lock);

		ret = pm_genpd_poweron(parent);
		if (ret)
			return ret;

		goto start;
	}

	if (genpd->power_on) {
		int ret = genpd->power_on(genpd);
		if (ret)
			goto out;
	}

	genpd->status = GPD_STATE_ACTIVE;
	if (parent)
		parent->sd_count++;

 out:
	mutex_unlock(&genpd->lock);
	if (parent)