linux/drivers/base/power/runtime.c
Rafael J. Wysocki feb70af0e3 PM: Do not use the syscore flag for runtime PM
The syscore device PM flag used to mark the devices (belonging to
PM domains) that should never be turned off, except for the system
core (syscore) suspend/hibernation and resume stages, need not be
accessed by the runtime PM core functions, because all of the devices
it is set for need to be marked as "irq safe" anyway and are
protected from being turned off by runtime PM by ensuring that their
usage counters are always set.

For this reason, make the syscore flag system-wide PM-specific
and simplify the code used for manipulating it, because it need not
acquire the device's power.lock any more.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-04 01:36:05 +02:00

1315 lines
36 KiB
C

/*
* drivers/base/power/runtime.c - Helper functions for device runtime 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/export.h>
#include <linux/pm_runtime.h>
#include <trace/events/rpm.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;
unsigned long delta;
delta = now - dev->power.accounting_timestamp;
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 (dev->power.disable_depth > 0)
retval = -EACCES;
else if (atomic_read(&dev->power.usage_count) > 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_pm_qos_read_value(dev) < 0)
retval = -EPERM;
else if (dev->power.runtime_status == RPM_SUSPENDED)
retval = 1;
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 (dev->power.irq_safe)
spin_unlock(&dev->power.lock);
else
spin_unlock_irq(&dev->power.lock);
retval = cb(dev);
if (dev->power.irq_safe)
spin_lock(&dev->power.lock);
else
spin_lock_irq(&dev->power.lock);
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 runtime 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;
trace_rpm_idle(dev, rpmflags);
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->pm_domain)
callback = dev->pm_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 && dev->driver && dev->driver->pm)
callback = dev->driver->pm->runtime_idle;
if (callback)
__rpm_callback(callback, dev);
dev->power.idle_notification = false;
wake_up_all(&dev->power.wait_queue);
out:
trace_rpm_return_int(dev, _THIS_IP_, retval);
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)
{
int retval;
if (!cb)
return -ENOSYS;
retval = __rpm_callback(cb, dev);
dev->power.runtime_error = retval;
return retval != -EACCES ? retval : -EIO;
}
/**
* rpm_suspend - Carry out runtime suspend of given device.
* @dev: Device to suspend.
* @rpmflags: Flag bits.
*
* Check if the device's runtime PM status allows it to be suspended.
* Cancel a pending idle notification, autosuspend or suspend. 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. If the RPM_ASYNC flag is set then queue a suspend request;
* otherwise run the ->runtime_suspend() callback directly. When
* ->runtime_suspend succeeded, if a deferred resume was requested while
* the callback was running then carry it out, otherwise send an idle
* notification for its parent (if the suspend succeeded and both
* ignore_children of parent->power and irq_safe of dev->power are not set).
* 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;
trace_rpm_suspend(dev, 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;
}
if (dev->power.irq_safe) {
spin_unlock(&dev->power.lock);
cpu_relax();
spin_lock(&dev->power.lock);
goto repeat;
}
/* 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->pm_domain)
callback = dev->pm_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;
if (!callback && dev->driver && dev->driver->pm)
callback = dev->driver->pm->runtime_suspend;
retval = rpm_callback(callback, dev);
if (retval)
goto fail;
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:
trace_rpm_return_int(dev, _THIS_IP_, retval);
return retval;
fail:
__update_runtime_status(dev, RPM_ACTIVE);
dev->power.deferred_resume = false;
wake_up_all(&dev->power.wait_queue);
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);
}
goto out;
}
/**
* rpm_resume - Carry out runtime resume of given device.
* @dev: Device to resume.
* @rpmflags: Flag bits.
*
* Check if the device's runtime 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;
trace_rpm_resume(dev, rpmflags);
repeat:
if (dev->power.runtime_error)
retval = -EINVAL;
else if (dev->power.disable_depth > 0)
retval = -EACCES;
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;
}
if (dev->power.irq_safe) {
spin_unlock(&dev->power.lock);
cpu_relax();
spin_lock(&dev->power.lock);
goto repeat;
}
/* 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 runtime 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->pm_domain)
callback = dev->pm_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;
if (!callback && dev->driver && dev->driver->pm)
callback = dev->driver->pm->runtime_resume;
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);
}
trace_rpm_return_int(dev, _THIS_IP_, retval);
return retval;
}
/**
* pm_runtime_work - Universal runtime 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 runtime 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 runtime 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,
* or if pm_runtime_irq_safe() has been called.
*/
int __pm_runtime_idle(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_idle(dev, rpmflags);
spin_unlock_irqrestore(&dev->power.lock, flags);
return retval;
}
EXPORT_SYMBOL_GPL(__pm_runtime_idle);
/**
* __pm_runtime_suspend - Entry point for runtime 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,
* or if pm_runtime_irq_safe() has been called.
*/
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 runtime 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,
* or if pm_runtime_irq_safe() has been called.
*/
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 runtime PM status of a device.
* @dev: Device to handle.
* @status: New runtime PM status of the device.
*
* If runtime 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 runtime 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
* runtime 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 runtime 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 runtime 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 runtime PM requests for the device and wait for all
* operations in progress to complete. The device can be either active or
* suspended after its runtime 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 runtime PM.
*/
void __pm_runtime_disable(struct device *dev, bool check_resume)
{
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 runtime 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 runtime 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 runtime 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 runtime 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 runtime 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 runtime PM
* callbacks of its own. The runtime 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 runtime suspends. If it
* changes the other way, allow runtime 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 runtime
* suspends as needed.
*/
void __pm_runtime_use_autosuspend(struct device *dev, bool use)
{
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.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 runtime 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);
}