- 根目录:
- 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.
* Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
*
* This file is released under the GPLv2.
*/
#include <linux/sched.h>
#include <linux/pm_runtime.h>
#include "power.h"
static int rpm_resume(struct device *dev, int rpmflags);
static int rpm_suspend(struct device *dev, int rpmflags);
/**
* update_pm_runtime_accounting - Update the time accounting of power states
* @dev: Device to update the accounting for
*
* In order to be able to have time accounting of the various power states
* (as used by programs such as PowerTOP to show the effectiveness of runtime
* PM), we need to track the time spent in each state.
* update_pm_runtime_accounting must be called each time before the
* runtime_status field is updated, to account the time in the old state
* correctly.
*/
void update_pm_runtime_accounting(struct device *dev)
{
unsigned long now = jiffies;
int delta;
delta = now - dev->power.accounting_timestamp;
if (delta < 0)
delta = 0;
dev->power.accounting_timestamp = now;
if (dev->power.disable_depth > 0)
return;
if (dev->power.runtime_status == RPM_SUSPENDED)
dev->power.suspended_jiffies += delta;
else
dev->power.active_jiffies += delta;
}
static void __update_runtime_status(struct device *dev, enum rpm_status status)
{
update_pm_runtime_accounting(dev);
dev->power.runtime_status = status;
}
/**
* 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_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
* @dev: Device to handle.
*
* Compute the autosuspend-delay expiration time based on the device's
* power.last_busy time. If the delay has already expired or is disabled
* (negative) or the power.use_autosuspend flag isn't set, return 0.
* Otherwise return the expiration time in jiffies (adjusted to be nonzero).
*
* This function may be called either with or without dev->power.lock held.
* Either way it can be racy, since power.last_busy may be updated at any time.
*/
unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
{
int autosuspend_delay;
long elapsed;
unsigned long last_busy;
unsigned long expires = 0;
if (!dev->power.use_autosuspend)
goto out;
autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
if (autosuspend_delay < 0)
goto out;
last_busy = ACCESS_ONCE(dev->power.last_busy);
elapsed = jiffies - last_busy;
if (elapsed < 0)
goto out; /* jiffies has wrapped around. */
/*
* If the autosuspend_delay is >= 1 second, align the timer by rounding
* up to the nearest second.
*/
expires = last_busy + msecs_to_jiffies(autosuspend_delay);
if (autosuspend_delay >= 1000)
expires = round_jiffies(expires);
expires += !expires;
if (elapsed >= expires - last_busy)
expires = 0; /* Already expired. */
out:
return expires;
}
EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
/**
* rpm_check_suspend_allowed - Test whether a device may be suspended.
* @dev: Device to test.
*/
static int rpm_check_suspend_allowed(struct device *dev)
{
int retval = 0;
if (dev->power.runtime_error)
retval = -EINVAL;
else if (atomic_read(&dev->power.usage_count) > 0
|| dev->power.disable_depth > 0)
retval = -EAGAIN;
else if (!pm_children_suspended(dev))
retval = -EBUSY;
/* Pending resume requests take precedence over suspends. */
else if ((dev->power.deferred_resume
&& dev->power.runtime_status == RPM_SUSPENDING)
|| (dev->power.request_pending
&& dev->power.request == RPM_REQ_RESUME))
retval = -EAGAIN;
else if (dev->power.runtime_status == RPM_SUSPENDED)
retval = 1;
return retval;
}
/**
* rpm_idle - Notify device bus type if the device can be suspended.
* @dev: Device to notify the bus type about.
* @rpmflags: Flag bits.
*
* Check if the device's run-time PM status allows it to be suspended. If
* another idle notification has been started earlier, return immediately. If
* the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
* run the ->runtime_idle() callback directly.
*
* This function must be called under dev->power.lock with interrupts disabled.
*/
static int rpm_idle(struct device *dev, int rpmflags)
{
int (*callback)(struct device *);
int retval;
retval = rpm_check_suspend_allowed(dev);
if (retval < 0)
; /* Conditions are wrong. */
/* Idle notifications are allowed only in the RPM_ACTIVE state. */
else if (dev->power.runtime_status != RPM_ACTIVE)
retval = -EAGAIN;
/*
* Any pending request other than an idle notification takes
* precedence over us, except that the timer may be running.
*/
else if (dev->power.request_pending &&
dev->power.request > RPM_REQ_IDLE)
retval = -EAGAIN;
/* Act as though RPM_NOWAIT is always set. */
else if (dev->power.idle_notification)
retval = -EINPROGRESS;
if (retval)
goto out;
/* Pending requests need to be canceled. */
dev->power.request = RPM_REQ_NONE;
if (dev->power.no_callbacks) {
/* Assume ->runtime_idle() callback would have suspended. */
retval = rpm_suspend(dev, rpmflags);
goto out;
}
/* Carry out an asynchronous or a synchronous idle notification. */
if (rpmflags & RPM_ASYNC) {
dev->power.request = RPM_REQ_IDLE;
if (!dev->power.request_pending) {
dev->power.request_pending = true;
queue_work(pm_wq, &dev->power.work);
}
goto out;
}
dev->power.idle_notification = true;
if (dev->pwr_domain)
callback = dev->pwr_domain->ops.runtime_idle;
else if (dev->type && dev->type->pm)
callback = dev->type->pm->runtime_idle;
else if (dev->class && dev->class->pm)
callback = dev->class->pm->runtime_idle;
else if (dev->bus && dev->bus->pm)
callback = dev->bus->pm->runtime_idle;
else
callback = NULL;
if (callback) {
spin_unlock_irq(&dev->power.lock);
callback(dev);
spin_lock_irq(&dev->power.lock);
}
dev->power.idle_notification = false;
wake_up_all(&dev->power.wait_queue);
out:
return retval;
}
/**
* rpm_callback - Run a given runtime PM callback for a given device.
* @cb: Runtime PM callback to run.
* @dev: Device to run the callback for.
*/
static int rpm_callback(int (*cb)(struct device *), struct device *dev)
__releases(&dev->power.lock) __acquires(&dev->power.lock)
{
int retval;
if (!cb)
return -ENOSYS;
if (dev->power.irq_safe) {
retval = cb(dev);
} else {
spin_unlock_irq(&dev->power.lock);
retval = cb(dev);
spin_lock_irq(&dev->power.lock);
}
dev->power.runtime_error = retval;
return retval;
}
/**
* rpm_suspend - Carry out run-time suspend of given device.
* @dev: Device to suspend.
* @rpmflags: Flag bits.
*
* Check if the device's run-time PM status allows it to be suspended. If
* another suspend has been started earlier, either return immediately or wait
* for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC flags. Cancel a
* pending idle notification. If the RPM_ASYNC flag is set then queue a
* suspend request; otherwise run the ->runtime_suspend() callback directly.
* If a deferred resume was requested while the callback was running then carry
* it out; otherwise send an idle notification for the device (if the suspend
* failed) or for its parent (if the suspend succeeded).
* If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
* flag is set and the next autosuspend-delay expiration time is in the
* future, schedule another autosuspend attempt.
*
* This function must be called under dev->power.lock with interrupts disabled.
*/
static int rpm_suspend(struct device *dev, int rpmflags)
__releases(&dev->power.lock) __acquires(&dev->power.lock)
{
int (*callback)(struct device *);
struct device *parent = NULL;
int retval;
dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
repeat:
retval = rpm_check_suspend_allowed(dev);
if (retval < 0)
; /* Conditions are wrong. */
/* Synchronous suspends are not allowed in the RPM_RESUMING state. */
else if (dev->power.runtime_status == RPM_RESUMING &&
!(rpmflags & RPM_ASYNC))
retval = -EAGAIN;
if (retval)
goto out;
/* If the autosuspend_delay time hasn't expired yet, reschedule. */
if ((rpmflags & RPM_AUTO)
&& dev->power.runtime_status != RPM_SUSPENDING) {
unsigned long expires = pm_runtime_autosuspend_expiration(dev);
if (expires != 0) {
/* Pending requests need to be canceled. */
dev->power.request = RPM_REQ_NONE;
/*
* Optimization: If the timer is already running and is
* set to expire at or before the autosuspend delay,
* avoid the overhead of resetting it. Just let it
* expire; pm_suspend_timer_fn() will take care of the
* rest.
*/
if (!(dev->power.timer_expires && time_before_eq(
dev->power.timer_expires, expires))) {
dev->power.timer_expires = expires;
mod_timer(&dev->power.suspend_timer, expires);
}
dev->power.timer_autosuspends = 1;
goto out;
}
}
/* Other scheduled or pending requests need to be canceled. */
pm_runtime_cancel_pending(dev);
if (dev->power.runtime_status == RPM_SUSPENDING) {
DEFINE_WAIT(wait);
if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
retval = -EINPROGRESS;
goto out;
}
/* Wait for the other suspend running in parallel with us. */
for (;;) {
prepare_to_wait(&dev->power.wait_queue, &wait,
TASK_UNINTERRUPTIBLE);
if (dev->power.runtime_status != RPM_SUSPENDING)
break;
spin_unlock_irq(&dev->power.lock);
schedule();
spin_lock_irq(&dev->power.lock);
}
finish_wait(&dev->power.wait_queue, &wait);
goto repeat;
}
if (dev->power.no_callbacks)
goto no_callback; /* Assume success. */
/* Carry out an asynchronous or a synchronous suspend. */
if (rpmflags & RPM_ASYNC) {
dev->power.request = (rpmflags & RPM_AUTO) ?
RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
if (!dev->power.request_pending) {
dev->power.request_pending = true;
queue_work(pm_wq, &dev->power.work);
}
goto out;
}
__update_runtime_status(dev, RPM_SUSPENDING);
if (dev->pwr_domain)
callback = dev->pwr_domain->ops.runtime_suspend;
else if (dev->type && dev->type->pm)
callback = dev->type->pm->runtime_suspend;
else if (dev->class && dev->class->pm)
callback = dev->class->pm->runtime_suspend;
else if (dev->bus && dev->bus->pm)
callback = dev->bus->pm->runtime_suspend;
else
callback = NULL;
retval = rpm_callback(callback, dev);
if (retval) {
__update_runtime_status(dev, RPM_ACTIVE);
dev->power.deferred_resume = 0;
if (retval == -EAGAIN || retval == -EBUSY) {
dev->power.runtime_error = 0;
/*
* If the callback routine failed an autosuspend, and
* if the last_busy time has been updated so that there
* is a new autosuspend expiration time, automatically
* reschedule another autosuspend.
*/
if ((rpmflags & RPM_AUTO) &&
pm_runtime_autosuspend_expiration(dev) != 0)
goto repeat;
} else {
pm_runtime_cancel_pending(dev);
}
} else {
no_callback:
__update_runtime_status(dev, RPM_SUSPENDED);
pm_runtime_deactivate_timer(dev);
if (dev->parent) {
parent = dev->parent;
atomic_add_unless(&parent->power.child_count, -1, 0);
}
}
wake_up_all(&dev->power.wait_queue);
if (dev->power.deferred_resume) {
dev->power.deferred_resume = false;
rpm_resume(dev, 0);
retval = -EAGAIN;
goto out;
}
/* Maybe the parent is now able to suspend. */
if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
spin_unlock(&dev->power.lock);
spin_lock(&parent->power.lock);
rpm_idle(parent, RPM_ASYNC);
spin_unlock(&parent->power.lock);
spin_lock(&dev->power.lock);
}
out:
dev_dbg(dev, "%s returns %d\n", __func__, retval);
return retval;
}
/**
* rpm_resume - Carry out run-time resume of given device.
* @dev: Device to resume.
* @rpmflags: Flag bits.
*
* Check if the device's run-time PM status allows it to be resumed. Cancel
* any scheduled or pending requests. If another resume has been started
* earlier, either return immediately or wait for it to finish, depending on the
* RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
* parallel with this function, either tell the other process to resume after
* suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
* flag is set then queue a resume request; otherwise run the
* ->runtime_resume() callback directly. Queue an idle notification for the
* device if the resume succeeded.
*
* This function must be called under dev->power.lock with interrupts disabled.
*/
static int rpm_resume(struct device *dev, int rpmflags)
__releases(&dev->power.lock) __acquires(&dev->power.lock)
{
int (*callback)(struct device *);
struct device *parent = NULL;
int retval = 0;
dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
repeat:
if (dev->power.runtime_error)
retval = -EINVAL;
else if (dev->power.disable_depth > 0)
retval = -EAGAIN;
if (retval)
goto out;
/*
* Other scheduled or pending requests need to be canceled. Small
* optimization: If an autosuspend timer is running, leave it running
* rather than cancelling it now only to restart it again in the near
* future.
*/
dev->power.request = RPM_REQ_NONE;
if (!dev->power.timer_autosuspends)
pm_runtime_deactivate_timer(dev);
if (dev->power.runtime_status == RPM_ACTIVE) {
retval = 1;
goto out;
}
if (dev->power.runtime_status == RPM_RESUMING
|| dev->power.runtime_status == RPM_SUSPENDING) {
DEFINE_WAIT(wait);
if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
if (dev->power.runtime_status == RPM_SUSPENDING)
dev->power.deferred_resume = true;
else
retval = -EINPROGRESS;
goto out;
}
/* Wait for the operation carried out in parallel with us. */
for (;;) {
prepare_to_wait(&dev->power.wait_queue, &wait,
TASK_UNINTERRUPTIBLE);
if (dev->power.runtime_status != RPM_RESUMING
&& dev->power.runtime_status != RPM_SUSPENDING)
break;
spin_unlock_irq(&dev->power.lock);
schedule();
spin_lock_irq(&dev->power.lock);
}
finish_wait(&dev->power.wait_queue, &wait);
goto repeat;
}
/*
* See if we can skip waking up the parent. This is safe only if
* power.no_callbacks is set, because otherwise we don't know whether
* the resume will actually succeed.
*/
if (dev->power.no_callbacks && !parent && dev->parent) {
spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
if (dev->parent->power.disable_depth > 0
|| dev->parent->power.ignore_children
|| dev->parent->power.runtime_status == RPM_ACTIVE) {
atomic_inc(&dev->parent->power.child_count);
spin_unlock(&dev->parent->power.lock);
retval = 1;
goto no_callback; /* Assume success. */
}
spin_unlock(&dev->parent->power.lock);
}
/* Carry out an asynchronous or a synchronous resume. */
if (rpmflags & RPM_ASYNC) {
dev->power.request = RPM_REQ_RESUME;
if (!dev->power.request_pending) {
dev->power.request_pending = true;
queue_work(pm_wq, &dev->power.work);
}
retval = 0;
goto out;
}
if (!parent && dev->parent) {
/*
* Increment the parent's usage counter and resume it if
* necessary. Not needed if dev is irq-safe; then the
* parent is permanently resumed.
*/
parent = dev->parent;
if (dev->power.irq_safe)
goto skip_parent;
spin_unlock(&dev->power.lock);
pm_runtime_get_noresume(parent);
spin_lock(&parent->power.lock);
/*
* We can resume if the parent's run-time PM is disabled or it
* is set to ignore children.
*/
if (!parent->power.disable_depth
&& !parent->power.ignore_children) {
rpm_resume(parent, 0);
if (parent->power.runtime_status != RPM_ACTIVE)
retval = -EBUSY;
}
spin_unlock(&parent->power.lock);
spin_lock(&dev->power.lock);
if (retval)
goto out;
goto repeat;
}
skip_parent:
if (dev->power.no_callbacks)
goto no_callback; /* Assume success. */
__update_runtime_status(dev, RPM_RESUMING);
if (dev->pwr_domain)
callback = dev->pwr_domain->ops.runtime_resume;
else if (dev->type && dev->type->pm)
callback = dev->type->pm->runtime_resume;
else if (dev->class && dev->class->pm)
callback = dev->class->pm->runtime_resume;
else if (dev->bus && dev->bus->pm)
callback = dev->bus->pm->runtime_resume;
else
callback = NULL;
retval = rpm_callback(callback, dev);
if (retval) {
__update_runtime_status(dev, RPM_SUSPENDED);
pm_runtime_cancel_pending(dev);
} else {
no_callback:
__update_runtime_status(dev, RPM_ACTIVE);
if (parent)
atomic_inc(&parent->power.child_count);
}
wake_up_all(&dev->power.wait_queue);
if (retval >= 0)
rpm_idle(dev, RPM_ASYNC);
out:
if (parent && !dev->power.irq_safe) {
spin_unlock_irq(&dev->power.lock);
pm_runtime_put(parent);
spin_lock_irq(&dev->power.lock);
}
dev_dbg(dev, "%s returns %d\n", __func__, retval);
return retval;
}
/**
* pm_runtime_work - Universal run-time PM work function.
* @work: Work structure used for scheduling the execution of this function.
*
* Use @work to get the device object the work is to be done for, determine what
* is to be done and execute the appropriate run-time PM function.
*/
static void pm_runtime_work(struct work_struct *work)
{
struct device *dev = container_of(work, struct device, power.work);
enum rpm_request req;
spin_lock_irq(&dev->power.lock);
if (!dev->power.request_pending)
goto out;
req = dev->power.request;
dev->power.request = RPM_REQ_NONE;
dev->power.request_pending = false;
switch (req) {
case RPM_REQ_NONE:
break;
case RPM_REQ_IDLE:
rpm_idle(dev, RPM_NOWAIT);
break;
case RPM_REQ_SUSPEND:
rpm_suspend(dev, RPM_NOWAIT);
break;
case RPM_REQ_AUTOSUSPEND:
rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
break;
case RPM_REQ_RESUME:
rpm_resume(dev, RPM_NOWAIT);
break;
}
out:
spin_unlock_irq(&dev->power.lock);
}
/**
* pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
* @data: Device pointer passed by pm_schedule_suspend().
*
* Check if the time is right and queue a suspend request.
*/
static void pm_suspend_timer_fn(unsigned long data)
{
struct device *dev = (struct device *)data;
unsigned long flags;
unsigned long expires;
spin_lock_irqsave(&dev->power.lock, flags);
expires = dev->power.timer_expires;
/* If 'expire' is after 'jiffies' we've been called too early. */
if (expires > 0 && !time_after(expires, jiffies)) {
dev->power.timer_expires = 0;
rpm_suspend(dev, dev->power.timer_autosuspends ?
(RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
}
spin_unlock_irqrestore(&dev->power.lock, flags);
}
/**
* pm_schedule_suspend - Set up a timer to submit a suspend request in future.
* @dev: Device to suspend.
* @delay: Time to wait before submitting a suspend request, in milliseconds.
*/
int pm_schedule_suspend(struct device *dev, unsigned int delay)
{
unsigned long flags;
int retval;
spin_lock_irqsave(&dev->power.lock, flags);
if (!delay) {
retval = rpm_suspend(dev, RPM_ASYNC);
goto out;
}
retval = rpm_check_suspend_allowed(dev);
if (retval)
goto out;
/* Other scheduled or pending requests need to be canceled. */
pm_runtime_cancel_pending(dev);
dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
dev->power.timer_expires += !dev->power.timer_expires;
dev->power.timer_autosuspends = 0;
mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
out:
spin_unlock_irqrestore(&dev->power.lock, flags);
return retval;
}
EXPORT_SYMBOL_GPL(pm_schedule_suspend);
/**
* __pm_runtime_idle - Entry point for run-time idle operations.
* @dev: Device to send idle notification for.
* @rpmflags: Flag bits.
*
* If the RPM_GET_PUT flag is set, decrement the device's usage count and
* return immediately if it is larger than zero. Then carry out an idle
* notification, either synchronous or asynchronous.
*
* This routine may be called in atomic context if the RPM_ASYNC flag is set.
*/
int __pm_runtime_idle(struct device *dev, int rpmflags)
{
unsigned long flags;
int retval;
might_sleep_if(!(rpmflags & RPM_ASYNC));
if (rpmflags & RPM_GET_PUT) {
if (!atomic_dec_and_test(&dev->power.usage_count))
return 0;
}
spin_lock_irqsave(&dev->power.lock, flags);
retval = rpm_idle(dev, rpmflags);
spin_unlock_irqrestore(&dev->power.lock, flags);
return retval;
}
EXPORT_SYMBOL_GPL(__pm_runtime_idle);
/**
* __pm_runtime_suspend - Entry point for run-time put/suspend operations.
* @dev: Device to suspend.
* @rpmflags: Flag bits.
*
* If the RPM_GET_PUT flag is set, decrement the device's usage count and
* return immediately if it is larger than zero. Then carry out a suspend,
* either synchronous or asynchronous.
*
* This routine may be called in atomic context if the RPM_ASYNC flag is set.
*/
int __pm_runtime_suspend(struct device *dev, int rpmflags)
{
unsigned long flags;
int retval;
might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
if (rpmflags & RPM_GET_PUT) {
if (!atomic_dec_and_test(&dev->power.usage_count))
return 0;
}
spin_lock_irqsave(&dev->power.lock, flags);
retval = rpm_suspend(dev, rpmflags);
spin_unlock_irqrestore(&dev->power.lock, flags);
return retval;
}
EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
/**
* __pm_runtime_resume - Entry point for run-time resume operations.
* @dev: Device to resume.
* @rpmflags: Flag bits.
*
* If the RPM_GET_PUT flag is set, increment the device's usage count. Then
* carry out a resume, either synchronous or asynchronous.
*
* This routine may be called in atomic context if the RPM_ASYNC flag is set.
*/
int __pm_runtime_resume(struct device *dev, int rpmflags)
{
unsigned long flags;
int retval;
might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
if (rpmflags & RPM_GET_PUT)
atomic_inc(&dev->power.usage_count);
spin_lock_irqsave(&dev->power.lock, flags);
retval = rpm_resume(dev, rpmflags);
spin_unlock_irqrestore(&dev->power.lock, flags);
return retval;
}
EXPORT_SYMBOL_GPL(__pm_runtime_resume);
/**
* __pm_runtime_set_status - Set run-time PM status of a device.
* @dev: Device to handle.
* @status: New run-time PM status of the device.
*
* If run-time PM of the device is disabled or its power.runtime_error field is
* different from zero, the status may be changed either to RPM_ACTIVE, or to
* RPM_SUSPENDED, as long as that reflects the actual state of the device.
* However, if the device has a parent and the parent is not active, and the
* parent's power.ignore_children flag is unset, the device's status cannot be
* set to RPM_ACTIVE, so -EBUSY is returned in that case.
*
* If successful, __pm_runtime_set_status() clears the power.runtime_error field
* and the device parent's counter of unsuspended children is modified to
* reflect the new status. If the new status is RPM_SUSPENDED, an idle
* notification request for the parent is submitted.
*/
int __pm_runtime_set_status(struct device *dev, unsigned int status)
{
struct device *parent = dev->parent;
unsigned long flags;
bool notify_parent = false;
int error = 0;
if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
return -EINVAL;
spin_lock_irqsave(&dev->power.lock, flags);
if (!dev->power.runtime_error && !dev->power.disable_depth) {
error = -EAGAIN;
goto out;
}
if (dev->power.runtime_status == status)
goto out_set;
if (status == RPM_SUSPENDED) {
/* It always is possible to set the status to 'suspended'. */
if (parent) {
atomic_add_unless(&parent->power.child_count, -1, 0);
notify_parent = !parent->power.ignore_children;
}
goto out_set;
}
if (parent) {
spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
/*
* It is invalid to put an active child under a parent that is
* not active, has run-time PM enabled and the
* 'power.ignore_children' flag unset.
*/
if (!parent->power.disable_depth
&& !parent->power.ignore_children
&& parent->power.runtime_status != RPM_ACTIVE)
error = -EBUSY;
else if (dev->power.runtime_status == RPM_SUSPENDED)
atomic_inc(&parent->power.child_count);
spin_unlock(&parent->power.lock);
if (error)
goto out;
}
out_set:
__update_runtime_status(dev, status);
dev->power.runtime_error = 0;
out:
spin_unlock_irqrestore(&dev->power.lock, flags);
if (notify_parent)
pm_request_idle(parent);
return error;
}
EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
/**
* __pm_runtime_barrier - Cancel pending requests and wait for completions.
* @dev: Device to handle.
*
* Flush all pending requests for the device from pm_wq and wait for all
* run-time PM operations involving the device in progress to complete.
*
* Should be called under dev->power.lock with interrupts disabled.
*/
static void __pm_runtime_barrier(struct device *dev)
{
pm_runtime_deactivate_timer(dev);
if (dev->power.request_pending) {
dev->power.request = RPM_REQ_NONE;
spin_unlock_irq(&dev->power.lock);
cancel_work_sync(&dev->power.work);
spin_lock_irq(&dev->power.lock);
dev->power.request_pending = false;
}
if (dev->power.runtime_status == RPM_SUSPENDING
|| dev->power.runtime_status == RPM_RESUMING
|| dev->power.idle_notification) {
DEFINE_WAIT(wait);
/* Suspend, wake-up or idle notification in progress. */
for (;;) {
prepare_to_wait(&dev->power.wait_queue, &wait,
TASK_UNINTERRUPTIBLE);
if (dev->power.runtime_status != RPM_SUSPENDING
&& dev->power.runtime_status != RPM_RESUMING
&& !dev->power.idle_notification)
break;
spin_unlock_irq(&dev->power.lock);
schedule();
spin_lock_irq(&dev->power.lock);
}
finish_wait(&dev->power.wait_queue, &wait);
}
}
/**
* pm_runtime_barrier - Flush pending requests and wait for completions.
* @dev: Device to handle.
*
* Prevent the device from being suspended by incrementing its usage counter and
* if there's a pending resume request for the device, wake the device up.
* Next, make sure that all pending requests for the device have been flushed
* from pm_wq and wait for all run-time PM operations involving the device in
* progress to complete.
*
* Return value:
* 1, if there was a resume request pending and the device had to be woken up,
* 0, otherwise
*/
int pm_runtime_barrier(struct device *dev)
{
int retval = 0;
pm_runtime_get_noresume(dev);
spin_lock_irq(&dev->power.lock);
if (dev->power.request_pending
&& dev->power.request == RPM_REQ_RESUME) {
rpm_resume(dev, 0);
retval = 1;
}
__pm_runtime_barrier(dev);
spin_unlock_irq(&dev->power.lock);
pm_runtime_put_noidle(dev);
return retval;
}
EXPORT_SYMBOL_GPL(pm_runtime_barrier);
/**
* __pm_runtime_disable - Disable run-time PM of a device.
* @dev: Device to handle.
* @check_resume: If set, check if there's a resume request for the device.
*
* Increment power.disable_depth for the device and if was zero previously,
* cancel all pending run-time PM requests for the device and wait for all
* operations in progress to complete. The device can be either active or
* suspended after its run-time PM has been disabled.
*
* If @check_resume is set and there's a resume request pending when
* __pm_runtime_disable() is called and power.disable_depth is zero, the
* function will wake up the device before disabling its run-time PM.
*/
void __pm_runtime_disable(struct device *dev, bool check_resume)
{
might_sleep();
spin_lock_irq(&dev->power.lock);
if (dev->power.disable_depth > 0) {
dev->power.disable_depth++;
goto out;
}
/*
* Wake up the device if there's a resume request pending, because that
* means there probably is some I/O to process and disabling run-time PM
* shouldn't prevent the device from processing the I/O.
*/
if (check_resume && dev->power.request_pending
&& dev->power.request == RPM_REQ_RESUME) {
/*
* Prevent suspends and idle notifications from being carried
* out after we have woken up the device.
*/
pm_runtime_get_noresume(dev);
rpm_resume(dev, 0);
pm_runtime_put_noidle(dev);
}
if (!dev->power.disable_depth++)
__pm_runtime_barrier(dev);
out:
spin_unlock_irq(&dev->power.lock);
}
EXPORT_SYMBOL_GPL(__pm_runtime_disable);
/**
* pm_runtime_enable - Enable run-time PM of a device.
* @dev: Device to handle.
*/
void pm_runtime_enable(struct device *dev)
{
unsigned long flags;
spin_lock_irqsave(&dev->power.lock, flags);
if (dev->power.disable_depth > 0)
dev->power.disable_depth--;
else
dev_warn(dev, "Unbalanced %s!\n", __func__);
spin_unlock_irqrestore(&dev->power.lock, flags);
}
EXPORT_SYMBOL_GPL(pm_runtime_enable);
/**
* pm_runtime_forbid - Block run-time PM of a device.
* @dev: Device to handle.
*
* Increase the device's usage count and clear its power.runtime_auto flag,
* so that it cannot be suspended at run time until pm_runtime_allow() is called
* for it.
*/
void pm_runtime_forbid(struct device *dev)
{
spin_lock_irq(&dev->power.lock);
if (!dev->power.runtime_auto)
goto out;
dev->power.runtime_auto = false;
atomic_inc(&dev->power.usage_count);
rpm_resume(dev, 0);
out:
spin_unlock_irq(&dev->power.lock);
}
EXPORT_SYMBOL_GPL(pm_runtime_forbid);
/**
* pm_runtime_allow - Unblock run-time PM of a device.
* @dev: Device to handle.
*
* Decrease the device's usage count and set its power.runtime_auto flag.
*/
void pm_runtime_allow(struct device *dev)
{
spin_lock_irq(&dev->power.lock);
if (dev->power.runtime_auto)
goto out;
dev->power.runtime_auto = true;
if (atomic_dec_and_test(&dev->power.usage_count))
rpm_idle(dev, RPM_AUTO);
out:
spin_unlock_irq(&dev->power.lock);
}
EXPORT_SYMBOL_GPL(pm_runtime_allow);
/**
* pm_runtime_no_callbacks - Ignore run-time PM callbacks for a device.
* @dev: Device to handle.
*
* Set the power.no_callbacks flag, which tells the PM core that this
* device is power-managed through its parent and has no run-time PM
* callbacks of its own. The run-time sysfs attributes will be removed.
*/
void pm_runtime_no_callbacks(struct device *dev)
{
spin_lock_irq(&dev->power.lock);
dev->power.no_callbacks = 1;
spin_unlock_irq(&dev->power.lock);
if (device_is_registered(dev))
rpm_sysfs_remove(dev);
}
EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
/**
* pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
* @dev: Device to handle
*
* Set the power.irq_safe flag, which tells the PM core that the
* ->runtime_suspend() and ->runtime_resume() callbacks for this device should
* always be invoked with the spinlock held and interrupts disabled. It also
* causes the parent's usage counter to be permanently incremented, preventing
* the parent from runtime suspending -- otherwise an irq-safe child might have
* to wait for a non-irq-safe parent.
*/
void pm_runtime_irq_safe(struct device *dev)
{
if (dev->parent)
pm_runtime_get_sync(dev->parent);
spin_lock_irq(&dev->power.lock);
dev->power.irq_safe = 1;
spin_unlock_irq(&dev->power.lock);
}
EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
/**
* update_autosuspend - Handle a change to a device's autosuspend settings.
* @dev: Device to handle.
* @old_delay: The former autosuspend_delay value.
* @old_use: The former use_autosuspend value.
*
* Prevent runtime suspend if the new delay is negative and use_autosuspend is
* set; otherwise allow it. Send an idle notification if suspends are allowed.
*
* This function must be called under dev->power.lock with interrupts disabled.
*/
static void update_autosuspend(struct device *dev, int old_delay, int old_use)
{
int delay = dev->power.autosuspend_delay;
/* Should runtime suspend be prevented now? */
if (dev->power.use_autosuspend && delay < 0) {
/* If it used to be allowed then prevent it. */
if (!old_use || old_delay >= 0) {
atomic_inc(&dev->power.usage_count);
rpm_resume(dev, 0);
}
}
/* Runtime suspend should be allowed now. */
else {
/* If it used to be prevented then allow it. */
if (old_use && old_delay < 0)
atomic_dec(&dev->power.usage_count);
/* Maybe we can autosuspend now. */
rpm_idle(dev, RPM_AUTO);
}
}
/**
* pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
* @dev: Device to handle.
* @delay: Value of the new delay in milliseconds.
*
* Set the device's power.autosuspend_delay value. If it changes to negative
* and the power.use_autosuspend flag is set, prevent run-time suspends. If it
* changes the other way, allow run-time suspends.
*/
void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
{
int old_delay, old_use;
spin_lock_irq(&dev->power.lock);
old_delay = dev->power.autosuspend_delay;
old_use = dev->power.use_autosuspend;
dev->power.autosuspend_delay = delay;
update_autosuspend(dev, old_delay, old_use);
spin_unlock_irq(&dev->power.lock);
}
EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
/**
* __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
* @dev: Device to handle.
* @use: New value for use_autosuspend.
*
* Set the device's power.use_autosuspend flag, and allow or prevent run-time
* suspends as needed.
*/
void __pm_runtime_use_autosuspend(struct device *dev, bool use)
{
int old_delay, old_use;
might_sleep();
spin_lock_irq(&dev->power.lock);
old_delay = dev->power.autosuspend_delay;
old_use = dev->power.use_autosuspend;
dev->power.use_autosuspend = use;
update_autosuspend(dev, old_delay, old_use);
spin_unlock_irq(&dev->power.lock);
}
EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
/**
* pm_runtime_init - Initialize run-time PM fields in given device object.
* @dev: Device object to initialize.
*/
void pm_runtime_init(struct device *dev)
{
dev->power.runtime_status = RPM_SUSPENDED;
dev->power.idle_notification = false;
dev->power.disable_depth = 1;
atomic_set(&dev->power.usage_count, 0);
dev->power.runtime_error = 0;
atomic_set(&dev->power.child_count, 0);
pm_suspend_ignore_children(dev, false);
dev->power.runtime_auto = true;
dev->power.request_pending = false;
dev->power.request = RPM_REQ_NONE;
dev->power.deferred_resume = false;
dev->power.accounting_timestamp = jiffies;
INIT_WORK(&dev->power.work, pm_runtime_work);
dev->power.timer_expires = 0;
setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
(unsigned long)dev);
init_waitqueue_head(&dev->power.wait_queue);
}
/**
* pm_runtime_remove - Prepare for removing a device from device hierarchy.
* @dev: Device object being removed from device hierarchy.
*/
void pm_runtime_remove(struct device *dev)
{
__pm_runtime_disable(dev, false);
/* Change the status back to 'suspended' to match the initial status. */
if (dev->power.runtime_status == RPM_ACTIVE)
pm_runtime_set_suspended(dev);
if (dev->power.irq_safe && dev->parent)
pm_runtime_put_sync(dev->parent);
}