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

/*
 * drivers/base/power/runtime.c - Helper functions for device run-time PM
 *
 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
 *
 * This file is released under the GPLv2.
 */

#include <linux/sched.h>
#include <linux/pm_runtime.h>
#include <linux/jiffies.h>

static int __pm_runtime_resume(struct device *dev, bool from_wq);
static int __pm_request_idle(struct device *dev);
static int __pm_request_resume(struct device *dev);

/**
 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
 * @dev: Device to handle.
 */
static void pm_runtime_deactivate_timer(struct device *dev)
{
	if (dev->power.timer_expires > 0) {
		del_timer(&dev->power.suspend_timer);
		dev->power.timer_expires = 0;
	}
}

/**
 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
 * @dev: Device to handle.
 */
static void pm_runtime_cancel_pending(struct device *dev)
{
	pm_runtime_deactivate_timer(dev);
	/*
	 * In case there's a request pending, make sure its work function will
	 * return without doing anything.
	 */
	dev->power.request = RPM_REQ_NONE;
}

/**
 * __pm_runtime_idle - Notify device bus type if the device can be suspended.
 * @dev: Device to notify the bus type about.
 *
 * This function must be called under dev->power.lock with interrupts disabled.
 */
static int __pm_runtime_idle(struct device *dev)
	__releases(&dev->power.lock) __acquires(&dev->power.lock)
{
	int retval = 0;

	dev_dbg(dev, "__pm_runtime_idle()!\n");

	if (dev->power.runtime_error)
		retval = -EINVAL;
	else if (dev->power.idle_notification)
		retval = -EINPROGRESS;
	else if (atomic_read(&dev->power.usage_count) > 0
	    || dev->power.disable_depth > 0
	    || dev->power.runtime_status != RPM_ACTIVE)
		retval = -EAGAIN;
	else if (!pm_children_suspended(dev))
		retval = -EBUSY;
	if (retval)
		goto out;

	if (dev->power.request_pending) {
		/*
		 * If an idle notification request is pending, cancel it.  Any
		 * other pending request takes precedence over us.
		 */
		if (dev->power.request == RPM_REQ_IDLE) {
			dev->power.request = RPM_REQ_NONE;
		} else if (dev->power.request != RPM_REQ_NONE) {
			retval = -EAGAIN;
			goto out;
		}
	}

	dev->power.idle_notification = true;

	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_idle) {
		spin_unlock_irq(&dev->power.lock);

		dev->bus->pm->runtime_idle(dev);

		spin_lock_irq(&dev->power.lock);
	}

	dev->power.idle_notification = false;
	wake_up_all(&dev->power.wait_queue);

 out:
	dev_dbg(dev, "__pm_runtime_idle() returns %d!\n", retval);

	return retval;
}

/**
 * pm_runtime_idle - Notify device bus type if the device can be suspended.
 * @dev: Device to notify the bus type about.
 */
int pm_runtime_idle(struct device *dev)
{
	int retval;

	spin_lock_irq(&dev->power.lock);
	retval = __pm_runtime_idle(dev);
	spin_unlock_irq(&dev->power.lock);

	return retval;
}
EXPORT_SYMBOL_GPL(pm_runtime_idle);

/**
 * __pm_runtime_suspend - Carry out run-time suspend of given device.
 * @dev: Device to suspend.
 * @from_wq: If set, the function has been called via pm_wq.
 *
 * Check if the device can be suspended and run the ->runtime_suspend() callback
 * provided by its bus type.  If another suspend has been started earlier, wait
 * for it to finish.  If an idle notification or suspend request is pending or
 * scheduled, cancel it.
 *
 * This function must be called under dev->power.lock with interrupts disabled.
 */
int __pm_runtime_suspend(struct device *dev, bool from_wq)
	__releases(&dev->power.lock) __acquires(&dev->power.lock)
{
	struct device *parent = NULL;
	bool notify = false;
	int retval = 0;

	dev_dbg(dev, "__pm_runtime_suspend()%s!\n",
		from_wq ? " from workqueue" : "");

 repeat:
	if (dev->power.runtime_error) {
		retval = -EINVAL;
		goto out;
	}

	/* Pending resume requests take precedence over us. */
	if (dev->power.request_pending
	    && dev->power.request == RPM_REQ_RESUME) {
		retval = -EAGAIN;
		goto out;
	}

	/* Other scheduled or pending requests need to be canceled. */
	pm_runtime_cancel_pending(dev);

	if (dev->power.runtime_status == RPM_SUSPENDED)
		retval =