linux/drivers/base/power/runtime.c
Michał Mirosław d229290689 PM-runtime: add tracepoints for usage_count changes
Add tracepoints to remaining places where device's power.usage_count
is changed.

This helps debugging where and why autosuspend is prevented.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-01-13 12:28:29 +01:00

1823 lines
50 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* 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>
*/
#include <linux/sched/mm.h>
#include <linux/ktime.h>
#include <linux/hrtimer.h>
#include <linux/export.h>
#include <linux/pm_runtime.h>
#include <linux/pm_wakeirq.h>
#include <trace/events/rpm.h>
#include "../base.h"
#include "power.h"
typedef int (*pm_callback_t)(struct device *);
static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
{
pm_callback_t cb;
const struct dev_pm_ops *ops;
if (dev->pm_domain)
ops = &dev->pm_domain->ops;
else if (dev->type && dev->type->pm)
ops = dev->type->pm;
else if (dev->class && dev->class->pm)
ops = dev->class->pm;
else if (dev->bus && dev->bus->pm)
ops = dev->bus->pm;
else
ops = NULL;
if (ops)
cb = *(pm_callback_t *)((void *)ops + cb_offset);
else
cb = NULL;
if (!cb && dev->driver && dev->driver->pm)
cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
return cb;
}
#define RPM_GET_CALLBACK(dev, callback) \
__rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
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.
*/
static void update_pm_runtime_accounting(struct device *dev)
{
u64 now, last, delta;
if (dev->power.disable_depth > 0)
return;
last = dev->power.accounting_timestamp;
now = ktime_get_mono_fast_ns();
dev->power.accounting_timestamp = now;
/*
* Because ktime_get_mono_fast_ns() is not monotonic during
* timekeeping updates, ensure that 'now' is after the last saved
* timesptamp.
*/
if (now < last)
return;
delta = now - last;
if (dev->power.runtime_status == RPM_SUSPENDED)
dev->power.suspended_time += delta;
else
dev->power.active_time += delta;
}
static void __update_runtime_status(struct device *dev, enum rpm_status status)
{
update_pm_runtime_accounting(dev);
dev->power.runtime_status = status;
}
static u64 rpm_get_accounted_time(struct device *dev, bool suspended)
{
u64 time;
unsigned long flags;
spin_lock_irqsave(&dev->power.lock, flags);
update_pm_runtime_accounting(dev);
time = suspended ? dev->power.suspended_time : dev->power.active_time;
spin_unlock_irqrestore(&dev->power.lock, flags);
return time;
}
u64 pm_runtime_active_time(struct device *dev)
{
return rpm_get_accounted_time(dev, false);
}
u64 pm_runtime_suspended_time(struct device *dev)
{
return rpm_get_accounted_time(dev, true);
}
EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
/**
* 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) {
hrtimer_try_to_cancel(&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 nanoseconds (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.
*/
u64 pm_runtime_autosuspend_expiration(struct device *dev)
{
int autosuspend_delay;
u64 expires;
if (!dev->power.use_autosuspend)
return 0;
autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
if (autosuspend_delay < 0)
return 0;
expires = READ_ONCE(dev->power.last_busy);
expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
if (expires > ktime_get_mono_fast_ns())
return expires; /* Expires in the future */
return 0;
}
EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
static int dev_memalloc_noio(struct device *dev, void *data)
{
return dev->power.memalloc_noio;
}
/*
* pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
* @dev: Device to handle.
* @enable: True for setting the flag and False for clearing the flag.
*
* Set the flag for all devices in the path from the device to the
* root device in the device tree if @enable is true, otherwise clear
* the flag for devices in the path whose siblings don't set the flag.
*
* The function should only be called by block device, or network
* device driver for solving the deadlock problem during runtime
* resume/suspend:
*
* If memory allocation with GFP_KERNEL is called inside runtime
* resume/suspend callback of any one of its ancestors(or the
* block device itself), the deadlock may be triggered inside the
* memory allocation since it might not complete until the block
* device becomes active and the involed page I/O finishes. The
* situation is pointed out first by Alan Stern. Network device
* are involved in iSCSI kind of situation.
*
* The lock of dev_hotplug_mutex is held in the function for handling
* hotplug race because pm_runtime_set_memalloc_noio() may be called
* in async probe().
*
* The function should be called between device_add() and device_del()
* on the affected device(block/network device).
*/
void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
{
static DEFINE_MUTEX(dev_hotplug_mutex);
mutex_lock(&dev_hotplug_mutex);
for (;;) {
bool enabled;
/* hold power lock since bitfield is not SMP-safe. */
spin_lock_irq(&dev->power.lock);
enabled = dev->power.memalloc_noio;
dev->power.memalloc_noio = enable;
spin_unlock_irq(&dev->power.lock);
/*
* not need to enable ancestors any more if the device
* has been enabled.
*/
if (enabled && enable)
break;
dev = dev->parent;
/*
* clear flag of the parent device only if all the
* children don't set the flag because ancestor's
* flag was set by any one of the descendants.
*/
if (!dev || (!enable &&
device_for_each_child(dev, NULL,
dev_memalloc_noio)))
break;
}
mutex_unlock(&dev_hotplug_mutex);
}
EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
/**
* 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 (!dev->power.ignore_children &&
atomic_read(&dev->power.child_count))
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_resume_latency(dev) == 0)
retval = -EPERM;
else if (dev->power.runtime_status == RPM_SUSPENDED)
retval = 1;
return retval;
}
static int rpm_get_suppliers(struct device *dev)
{
struct device_link *link;
list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
device_links_read_lock_held()) {
int retval;
if (!(link->flags & DL_FLAG_PM_RUNTIME) ||
READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND)
continue;
retval = pm_runtime_get_sync(link->supplier);
/* Ignore suppliers with disabled runtime PM. */
if (retval < 0 && retval != -EACCES) {
pm_runtime_put_noidle(link->supplier);
return retval;
}
refcount_inc(&link->rpm_active);
}
return 0;
}
static void rpm_put_suppliers(struct device *dev)
{
struct device_link *link;
list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
device_links_read_lock_held()) {
if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND)
continue;
while (refcount_dec_not_one(&link->rpm_active))
pm_runtime_put(link->supplier);
}
}
/**
* __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, idx;
bool use_links = dev->power.links_count > 0;
if (dev->power.irq_safe) {
spin_unlock(&dev->power.lock);
} else {
spin_unlock_irq(&dev->power.lock);
/*
* Resume suppliers if necessary.
*
* The device's runtime PM status cannot change until this
* routine returns, so it is safe to read the status outside of
* the lock.
*/
if (use_links && dev->power.runtime_status == RPM_RESUMING) {
idx = device_links_read_lock();
retval = rpm_get_suppliers(dev);
if (retval)
goto fail;
device_links_read_unlock(idx);
}
}
retval = cb(dev);
if (dev->power.irq_safe) {
spin_lock(&dev->power.lock);
} else {
/*
* If the device is suspending and the callback has returned
* success, drop the usage counters of the suppliers that have
* been reference counted on its resume.
*
* Do that if resume fails too.
*/
if (use_links
&& ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
|| (dev->power.runtime_status == RPM_RESUMING && retval))) {
idx = device_links_read_lock();
fail:
rpm_put_suppliers(dev);
device_links_read_unlock(idx);
}
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. If the ->runtime_idle callback
* doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
*
* 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_rcuidle(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)
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);
}
trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
return 0;
}
dev->power.idle_notification = true;
callback = RPM_GET_CALLBACK(dev, runtime_idle);
if (callback)
retval = __rpm_callback(callback, dev);
dev->power.idle_notification = false;
wake_up_all(&dev->power.wait_queue);
out:
trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
}
/**
* 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;
if (dev->power.memalloc_noio) {
unsigned int noio_flag;
/*
* Deadlock might be caused if memory allocation with
* GFP_KERNEL happens inside runtime_suspend and
* runtime_resume callbacks of one block device's
* ancestor or the block device itself. Network
* device might be thought as part of iSCSI block
* device, so network device and its ancestor should
* be marked as memalloc_noio too.
*/
noio_flag = memalloc_noio_save();
retval = __rpm_callback(cb, dev);
memalloc_noio_restore(noio_flag);
} else {
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_rcuidle(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) {
u64 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 &&
dev->power.timer_expires <= expires)) {
/*
* We add a slack of 25% to gather wakeups
* without sacrificing the granularity.
*/
u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) *
(NSEC_PER_MSEC >> 2);
dev->power.timer_expires = expires;
hrtimer_start_range_ns(&dev->power.suspend_timer,
ns_to_ktime(expires),
slack,
HRTIMER_MODE_ABS);
}
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);
callback = RPM_GET_CALLBACK(dev, runtime_suspend);
dev_pm_enable_wake_irq_check(dev, true);
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_rcuidle(dev, _THIS_IP_, retval);
return retval;
fail:
dev_pm_disable_wake_irq_check(dev);
__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_rcuidle(dev, rpmflags);
repeat:
if (dev->power.runtime_error)
retval = -EINVAL;
else if (dev->power.disable_depth == 1 && dev->power.is_suspended
&& dev->power.runtime_status == RPM_ACTIVE)
retval = 1;
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);
/*
* Resume the parent if it has runtime PM enabled and not been
* set to ignore its 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);
callback = RPM_GET_CALLBACK(dev, runtime_resume);
dev_pm_disable_wake_irq_check(dev);
retval = rpm_callback(callback, dev);
if (retval) {
__update_runtime_status(dev, RPM_SUSPENDED);
pm_runtime_cancel_pending(dev);
dev_pm_enable_wake_irq_check(dev, false);
} else {
no_callback:
__update_runtime_status(dev, RPM_ACTIVE);
pm_runtime_mark_last_busy(dev);
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_rcuidle(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 enum hrtimer_restart pm_suspend_timer_fn(struct hrtimer *timer)
{
struct device *dev = container_of(timer, struct device, power.suspend_timer);
unsigned long flags;
u64 expires;
spin_lock_irqsave(&dev->power.lock, flags);
expires = dev->power.timer_expires;
/*
* If 'expires' is after the current time, we've been called
* too early.
*/
if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
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);
return HRTIMER_NORESTART;
}
/**
* 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;
u64 expires;
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);
expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC;
dev->power.timer_expires = expires;
dev->power.timer_autosuspends = 0;
hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);
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;
if (rpmflags & RPM_GET_PUT) {
if (!atomic_dec_and_test(&dev->power.usage_count)) {
trace_rpm_usage_rcuidle(dev, rpmflags);
return 0;
}
}
might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
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;
if (rpmflags & RPM_GET_PUT) {
if (!atomic_dec_and_test(&dev->power.usage_count)) {
trace_rpm_usage_rcuidle(dev, rpmflags);
return 0;
}
}
might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
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 &&
dev->power.runtime_status != RPM_ACTIVE);
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_get_if_in_use - Conditionally bump up the device's usage counter.
* @dev: Device to handle.
*
* Return -EINVAL if runtime PM is disabled for the device.
*
* If that's not the case and if the device's runtime PM status is RPM_ACTIVE
* and the runtime PM usage counter is nonzero, increment the counter and
* return 1. Otherwise return 0 without changing the counter.
*/
int pm_runtime_get_if_in_use(struct device *dev)
{
unsigned long flags;
int retval;
spin_lock_irqsave(&dev->power.lock, flags);
retval = dev->power.disable_depth > 0 ? -EINVAL :
dev->power.runtime_status == RPM_ACTIVE
&& atomic_inc_not_zero(&dev->power.usage_count);
trace_rpm_usage_rcuidle(dev, 0);
spin_unlock_irqrestore(&dev->power.lock, flags);
return retval;
}
EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
/**
* __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.
*
* If @dev has any suppliers (as reflected by device links to them), and @status
* is RPM_ACTIVE, they will be activated upfront and if the activation of one
* of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead
* of the @status value) and the suppliers will be deacticated on exit. The
* error returned by the failing supplier activation will be returned in that
* case.
*/
int __pm_runtime_set_status(struct device *dev, unsigned int status)
{
struct device *parent = dev->parent;
bool notify_parent = false;
int error = 0;
if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
return -EINVAL;
spin_lock_irq(&dev->power.lock);
/*
* Prevent PM-runtime from being enabled for the device or return an
* error if it is enabled already and working.
*/
if (dev->power.runtime_error || dev->power.disable_depth)
dev->power.disable_depth++;
else
error = -EAGAIN;
spin_unlock_irq(&dev->power.lock);
if (error)
return error;
/*
* If the new status is RPM_ACTIVE, the suppliers can be activated
* upfront regardless of the current status, because next time
* rpm_put_suppliers() runs, the rpm_active refcounts of the links
* involved will be dropped down to one anyway.
*/
if (status == RPM_ACTIVE) {
int idx = device_links_read_lock();
error = rpm_get_suppliers(dev);
if (error)
status = RPM_SUSPENDED;
device_links_read_unlock(idx);
}
spin_lock_irq(&dev->power.lock);
if (dev->power.runtime_status == status || !parent)
goto out_set;
if (status == RPM_SUSPENDED) {
atomic_add_unless(&parent->power.child_count, -1, 0);
notify_parent = !parent->power.ignore_children;
} else {
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) {
dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
dev_name(dev),
dev_name(parent));
error = -EBUSY;
} else if (dev->power.runtime_status == RPM_SUSPENDED) {
atomic_inc(&parent->power.child_count);
}
spin_unlock(&parent->power.lock);
if (error) {
status = RPM_SUSPENDED;
goto out;
}
}
out_set:
__update_runtime_status(dev, status);
if (!error)
dev->power.runtime_error = 0;
out:
spin_unlock_irq(&dev->power.lock);
if (notify_parent)
pm_request_idle(parent);
if (status == RPM_SUSPENDED) {
int idx = device_links_read_lock();
rpm_put_suppliers(dev);
device_links_read_unlock(idx);
}
pm_runtime_enable(dev);
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 it 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);
}
/* Update time accounting before disabling PM-runtime. */
update_pm_runtime_accounting(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--;
/* About to enable runtime pm, set accounting_timestamp to now */
if (!dev->power.disable_depth)
dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
} else {
dev_warn(dev, "Unbalanced %s!\n", __func__);
}
WARN(!dev->power.disable_depth &&
dev->power.runtime_status == RPM_SUSPENDED &&
!dev->power.ignore_children &&
atomic_read(&dev->power.child_count) > 0,
"Enabling runtime PM for inactive device (%s) with active children\n",
dev_name(dev));
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 | RPM_ASYNC);
else
trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC);
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);
} else {
trace_rpm_usage_rcuidle(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;
INIT_WORK(&dev->power.work, pm_runtime_work);
dev->power.timer_expires = 0;
hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
dev->power.suspend_timer.function = pm_suspend_timer_fn;
init_waitqueue_head(&dev->power.wait_queue);
}
/**
* pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
* @dev: Device object to re-initialize.
*/
void pm_runtime_reinit(struct device *dev)
{
if (!pm_runtime_enabled(dev)) {
if (dev->power.runtime_status == RPM_ACTIVE)
pm_runtime_set_suspended(dev);
if (dev->power.irq_safe) {
spin_lock_irq(&dev->power.lock);
dev->power.irq_safe = 0;
spin_unlock_irq(&dev->power.lock);
if (dev->parent)
pm_runtime_put(dev->parent);
}
}
}
/**
* 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);
pm_runtime_reinit(dev);
}
/**
* pm_runtime_clean_up_links - Prepare links to consumers for driver removal.
* @dev: Device whose driver is going to be removed.
*
* Check links from this device to any consumers and if any of them have active
* runtime PM references to the device, drop the usage counter of the device
* (as many times as needed).
*
* Links with the DL_FLAG_MANAGED flag unset are ignored.
*
* Since the device is guaranteed to be runtime-active at the point this is
* called, nothing else needs to be done here.
*
* Moreover, this is called after device_links_busy() has returned 'false', so
* the status of each link is guaranteed to be DL_STATE_SUPPLIER_UNBIND and
* therefore rpm_active can't be manipulated concurrently.
*/
void pm_runtime_clean_up_links(struct device *dev)
{
struct device_link *link;
int idx;
idx = device_links_read_lock();
list_for_each_entry_rcu(link, &dev->links.consumers, s_node,
device_links_read_lock_held()) {
if (!(link->flags & DL_FLAG_MANAGED))
continue;
while (refcount_dec_not_one(&link->rpm_active))
pm_runtime_put_noidle(dev);
}
device_links_read_unlock(idx);
}
/**
* pm_runtime_get_suppliers - Resume and reference-count supplier devices.
* @dev: Consumer device.
*/
void pm_runtime_get_suppliers(struct device *dev)
{
struct device_link *link;
int idx;
idx = device_links_read_lock();
list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
device_links_read_lock_held())
if (link->flags & DL_FLAG_PM_RUNTIME) {
link->supplier_preactivated = true;
refcount_inc(&link->rpm_active);
pm_runtime_get_sync(link->supplier);
}
device_links_read_unlock(idx);
}
/**
* pm_runtime_put_suppliers - Drop references to supplier devices.
* @dev: Consumer device.
*/
void pm_runtime_put_suppliers(struct device *dev)
{
struct device_link *link;
int idx;
idx = device_links_read_lock();
list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
device_links_read_lock_held())
if (link->supplier_preactivated) {
link->supplier_preactivated = false;
if (refcount_dec_not_one(&link->rpm_active))
pm_runtime_put(link->supplier);
}
device_links_read_unlock(idx);
}
void pm_runtime_new_link(struct device *dev)
{
spin_lock_irq(&dev->power.lock);
dev->power.links_count++;
spin_unlock_irq(&dev->power.lock);
}
void pm_runtime_drop_link(struct device *dev)
{
spin_lock_irq(&dev->power.lock);
WARN_ON(dev->power.links_count == 0);
dev->power.links_count--;
spin_unlock_irq(&dev->power.lock);
}
static bool pm_runtime_need_not_resume(struct device *dev)
{
return atomic_read(&dev->power.usage_count) <= 1 &&
(atomic_read(&dev->power.child_count) == 0 ||
dev->power.ignore_children);
}
/**
* pm_runtime_force_suspend - Force a device into suspend state if needed.
* @dev: Device to suspend.
*
* Disable runtime PM so we safely can check the device's runtime PM status and
* if it is active, invoke its ->runtime_suspend callback to suspend it and
* change its runtime PM status field to RPM_SUSPENDED. Also, if the device's
* usage and children counters don't indicate that the device was in use before
* the system-wide transition under way, decrement its parent's children counter
* (if there is a parent). Keep runtime PM disabled to preserve the state
* unless we encounter errors.
*
* Typically this function may be invoked from a system suspend callback to make
* sure the device is put into low power state and it should only be used during
* system-wide PM transitions to sleep states. It assumes that the analogous
* pm_runtime_force_resume() will be used to resume the device.
*/
int pm_runtime_force_suspend(struct device *dev)
{
int (*callback)(struct device *);
int ret;
pm_runtime_disable(dev);
if (pm_runtime_status_suspended(dev))
return 0;
callback = RPM_GET_CALLBACK(dev, runtime_suspend);
ret = callback ? callback(dev) : 0;
if (ret)
goto err;
/*
* If the device can stay in suspend after the system-wide transition
* to the working state that will follow, drop the children counter of
* its parent, but set its status to RPM_SUSPENDED anyway in case this
* function will be called again for it in the meantime.
*/
if (pm_runtime_need_not_resume(dev))
pm_runtime_set_suspended(dev);
else
__update_runtime_status(dev, RPM_SUSPENDED);
return 0;
err:
pm_runtime_enable(dev);
return ret;
}
EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
/**
* pm_runtime_force_resume - Force a device into resume state if needed.
* @dev: Device to resume.
*
* Prior invoking this function we expect the user to have brought the device
* into low power state by a call to pm_runtime_force_suspend(). Here we reverse
* those actions and bring the device into full power, if it is expected to be
* used on system resume. In the other case, we defer the resume to be managed
* via runtime PM.
*
* Typically this function may be invoked from a system resume callback.
*/
int pm_runtime_force_resume(struct device *dev)
{
int (*callback)(struct device *);
int ret = 0;
if (!pm_runtime_status_suspended(dev) || pm_runtime_need_not_resume(dev))
goto out;
/*
* The value of the parent's children counter is correct already, so
* just update the status of the device.
*/
__update_runtime_status(dev, RPM_ACTIVE);
callback = RPM_GET_CALLBACK(dev, runtime_resume);
ret = callback ? callback(dev) : 0;
if (ret) {
pm_runtime_set_suspended(dev);
goto out;
}
pm_runtime_mark_last_busy(dev);
out:
pm_runtime_enable(dev);
return ret;
}
EXPORT_SYMBOL_GPL(pm_runtime_force_resume);