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alistair23-linux/drivers/base/power/main.c
Rafael J. Wysocki 1e2ef05bb8 PM: Limit race conditions between runtime PM and system sleep (v2) 
One of the roles of the PM core is to prevent different PM callbacks
executed for the same device object from racing with each other.
Unfortunately, after commit e866500247
(PM: Allow pm_runtime_suspend() to succeed during system suspend)
runtime PM callbacks may be executed concurrently with system
suspend/resume callbacks for the same device.

The main reason for commit e866500247
was that some subsystems and device drivers wanted to use runtime PM
helpers, pm_runtime_suspend() and pm_runtime_put_sync() in
particular, for carrying out the suspend of devices in their
.suspend() callbacks.  However, as it's been determined recently,
there are multiple reasons not to do so, inlcuding:

 * The caller really doesn't control the runtime PM usage counters,
   because user space can access them through sysfs and effectively
   block runtime PM.  That means using pm_runtime_suspend() or
   pm_runtime_get_sync() to suspend devices during system suspend
   may or may not work.

 * If a driver calls pm_runtime_suspend() from its .suspend()
   callback, it causes the subsystem's .runtime_suspend() callback to
   be executed, which leads to the call sequence:

   subsys->suspend(dev)
      driver->suspend(dev)
         pm_runtime_suspend(dev)
            subsys->runtime_suspend(dev)

   recursive from the subsystem's point of view.  For some subsystems
   that may actually work (e.g. the platform bus type), but for some
   it will fail in a rather spectacular fashion (e.g. PCI).  In each
   case it means a layering violation.

 * Both the subsystem and the driver can provide .suspend_noirq()
   callbacks for system suspend that can do whatever the
   .runtime_suspend() callbacks do just fine, so it really isn't
   necessary to call pm_runtime_suspend() during system suspend.

 * The runtime PM's handling of wakeup devices is usually different
   from the system suspend's one, so .runtime_suspend() may simply be
   inappropriate for system suspend.

 * System suspend is supposed to work even if CONFIG_PM_RUNTIME is
   unset.

 * The runtime PM workqueue is frozen before system suspend, so if
   whatever the driver is going to do during system suspend depends
   on it, that simply won't work.

Still, there is a good reason to allow pm_runtime_resume() to
succeed during system suspend and resume (for instance, some
subsystems and device drivers may legitimately use it to ensure that
their devices are in full-power states before suspending them).
Moreover, there is no reason to prevent runtime PM callbacks from
being executed in parallel with the system suspend/resume .prepare()
and .complete() callbacks and the code removed by commit
e866500247 went too far in this
respect.  On the other hand, runtime PM callbacks, including
.runtime_resume(), must not be executed during system suspend's
"late" stage of suspending devices and during system resume's "early"
device resume stage.

Taking all of the above into consideration, make the PM core
acquire a runtime PM reference to every device and resume it if
there's a runtime PM resume request pending right before executing
the subsystem-level .suspend() callback for it.  Make the PM core
drop references to all devices right after executing the
subsystem-level .resume() callbacks for them.  Additionally,
make the PM core disable the runtime PM framework for all devices
during system suspend, after executing the subsystem-level .suspend()
callbacks for them, and enable the runtime PM framework for all
devices during system resume, right before executing the
subsystem-level .resume() callbacks for them.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>
2011-07-06 10:51:58 +02:00

1115 lines
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/*
* drivers/base/power/main.c - Where the driver meets power management.
*
* Copyright (c) 2003 Patrick Mochel
* Copyright (c) 2003 Open Source Development Lab
*
* This file is released under the GPLv2
*
*
* The driver model core calls device_pm_add() when a device is registered.
* This will initialize the embedded device_pm_info object in the device
* and add it to the list of power-controlled devices. sysfs entries for
* controlling device power management will also be added.
*
* A separate list is used for keeping track of power info, because the power
* domain dependencies may differ from the ancestral dependencies that the
* subsystem list maintains.
*/
#include <linux/device.h>
#include <linux/kallsyms.h>
#include <linux/mutex.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/resume-trace.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/async.h>
#include <linux/suspend.h>
#include "../base.h"
#include "power.h"
/*
* The entries in the dpm_list list are in a depth first order, simply
* because children are guaranteed to be discovered after parents, and
* are inserted at the back of the list on discovery.
*
* Since device_pm_add() may be called with a device lock held,
* we must never try to acquire a device lock while holding
* dpm_list_mutex.
*/
LIST_HEAD(dpm_list);
LIST_HEAD(dpm_prepared_list);
LIST_HEAD(dpm_suspended_list);
LIST_HEAD(dpm_noirq_list);
static DEFINE_MUTEX(dpm_list_mtx);
static pm_message_t pm_transition;
static int async_error;
/**
* device_pm_init - Initialize the PM-related part of a device object.
* @dev: Device object being initialized.
*/
void device_pm_init(struct device *dev)
{
dev->power.is_prepared = false;
dev->power.is_suspended = false;
init_completion(&dev->power.completion);
complete_all(&dev->power.completion);
dev->power.wakeup = NULL;
spin_lock_init(&dev->power.lock);
pm_runtime_init(dev);
INIT_LIST_HEAD(&dev->power.entry);
}
/**
* device_pm_lock - Lock the list of active devices used by the PM core.
*/
void device_pm_lock(void)
{
mutex_lock(&dpm_list_mtx);
}
/**
* device_pm_unlock - Unlock the list of active devices used by the PM core.
*/
void device_pm_unlock(void)
{
mutex_unlock(&dpm_list_mtx);
}
/**
* device_pm_add - Add a device to the PM core's list of active devices.
* @dev: Device to add to the list.
*/
void device_pm_add(struct device *dev)
{
pr_debug("PM: Adding info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
mutex_lock(&dpm_list_mtx);
if (dev->parent && dev->parent->power.is_prepared)
dev_warn(dev, "parent %s should not be sleeping\n",
dev_name(dev->parent));
list_add_tail(&dev->power.entry, &dpm_list);
mutex_unlock(&dpm_list_mtx);
}
/**
* device_pm_remove - Remove a device from the PM core's list of active devices.
* @dev: Device to be removed from the list.
*/
void device_pm_remove(struct device *dev)
{
pr_debug("PM: Removing info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
complete_all(&dev->power.completion);
mutex_lock(&dpm_list_mtx);
list_del_init(&dev->power.entry);
mutex_unlock(&dpm_list_mtx);
device_wakeup_disable(dev);
pm_runtime_remove(dev);
}
/**
* device_pm_move_before - Move device in the PM core's list of active devices.
* @deva: Device to move in dpm_list.
* @devb: Device @deva should come before.
*/
void device_pm_move_before(struct device *deva, struct device *devb)
{
pr_debug("PM: Moving %s:%s before %s:%s\n",
deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
/* Delete deva from dpm_list and reinsert before devb. */
list_move_tail(&deva->power.entry, &devb->power.entry);
}
/**
* device_pm_move_after - Move device in the PM core's list of active devices.
* @deva: Device to move in dpm_list.
* @devb: Device @deva should come after.
*/
void device_pm_move_after(struct device *deva, struct device *devb)
{
pr_debug("PM: Moving %s:%s after %s:%s\n",
deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
/* Delete deva from dpm_list and reinsert after devb. */
list_move(&deva->power.entry, &devb->power.entry);
}
/**
* device_pm_move_last - Move device to end of the PM core's list of devices.
* @dev: Device to move in dpm_list.
*/
void device_pm_move_last(struct device *dev)
{
pr_debug("PM: Moving %s:%s to end of list\n",
dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
list_move_tail(&dev->power.entry, &dpm_list);
}
static ktime_t initcall_debug_start(struct device *dev)
{
ktime_t calltime = ktime_set(0, 0);
if (initcall_debug) {
pr_info("calling %s+ @ %i\n",
dev_name(dev), task_pid_nr(current));
calltime = ktime_get();
}
return calltime;
}
static void initcall_debug_report(struct device *dev, ktime_t calltime,
int error)
{
ktime_t delta, rettime;
if (initcall_debug) {
rettime = ktime_get();
delta = ktime_sub(rettime, calltime);
pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
error, (unsigned long long)ktime_to_ns(delta) >> 10);
}
}
/**
* dpm_wait - Wait for a PM operation to complete.
* @dev: Device to wait for.
* @async: If unset, wait only if the device's power.async_suspend flag is set.
*/
static void dpm_wait(struct device *dev, bool async)
{
if (!dev)
return;
if (async || (pm_async_enabled && dev->power.async_suspend))
wait_for_completion(&dev->power.completion);
}
static int dpm_wait_fn(struct device *dev, void *async_ptr)
{
dpm_wait(dev, *((bool *)async_ptr));
return 0;
}
static void dpm_wait_for_children(struct device *dev, bool async)
{
device_for_each_child(dev, &async, dpm_wait_fn);
}
/**
* pm_op - Execute the PM operation appropriate for given PM event.
* @dev: Device to handle.
* @ops: PM operations to choose from.
* @state: PM transition of the system being carried out.
*/
static int pm_op(struct device *dev,
const struct dev_pm_ops *ops,
pm_message_t state)
{
int error = 0;
ktime_t calltime;
calltime = initcall_debug_start(dev);
switch (state.event) {
#ifdef CONFIG_SUSPEND
case PM_EVENT_SUSPEND:
if (ops->suspend) {
error = ops->suspend(dev);
suspend_report_result(ops->suspend, error);
}
break;
case PM_EVENT_RESUME:
if (ops->resume) {
error = ops->resume(dev);
suspend_report_result(ops->resume, error);
}
break;
#endif /* CONFIG_SUSPEND */
#ifdef CONFIG_HIBERNATE_CALLBACKS
case PM_EVENT_FREEZE:
case PM_EVENT_QUIESCE:
if (ops->freeze) {
error = ops->freeze(dev);
suspend_report_result(ops->freeze, error);
}
break;
case PM_EVENT_HIBERNATE:
if (ops->poweroff) {
error = ops->poweroff(dev);
suspend_report_result(ops->poweroff, error);
}
break;
case PM_EVENT_THAW:
case PM_EVENT_RECOVER:
if (ops->thaw) {
error = ops->thaw(dev);
suspend_report_result(ops->thaw, error);
}
break;
case PM_EVENT_RESTORE:
if (ops->restore) {
error = ops->restore(dev);
suspend_report_result(ops->restore, error);
}
break;
#endif /* CONFIG_HIBERNATE_CALLBACKS */
default:
error = -EINVAL;
}
initcall_debug_report(dev, calltime, error);
return error;
}
/**
* pm_noirq_op - Execute the PM operation appropriate for given PM event.
* @dev: Device to handle.
* @ops: PM operations to choose from.
* @state: PM transition of the system being carried out.
*
* The driver of @dev will not receive interrupts while this function is being
* executed.
*/
static int pm_noirq_op(struct device *dev,
const struct dev_pm_ops *ops,
pm_message_t state)
{
int error = 0;
ktime_t calltime = ktime_set(0, 0), delta, rettime;
if (initcall_debug) {
pr_info("calling %s+ @ %i, parent: %s\n",
dev_name(dev), task_pid_nr(current),
dev->parent ? dev_name(dev->parent) : "none");
calltime = ktime_get();
}
switch (state.event) {
#ifdef CONFIG_SUSPEND
case PM_EVENT_SUSPEND:
if (ops->suspend_noirq) {
error = ops->suspend_noirq(dev);
suspend_report_result(ops->suspend_noirq, error);
}
break;
case PM_EVENT_RESUME:
if (ops->resume_noirq) {
error = ops->resume_noirq(dev);
suspend_report_result(ops->resume_noirq, error);
}
break;
#endif /* CONFIG_SUSPEND */
#ifdef CONFIG_HIBERNATE_CALLBACKS
case PM_EVENT_FREEZE:
case PM_EVENT_QUIESCE:
if (ops->freeze_noirq) {
error = ops->freeze_noirq(dev);
suspend_report_result(ops->freeze_noirq, error);
}
break;
case PM_EVENT_HIBERNATE:
if (ops->poweroff_noirq) {
error = ops->poweroff_noirq(dev);
suspend_report_result(ops->poweroff_noirq, error);
}
break;
case PM_EVENT_THAW:
case PM_EVENT_RECOVER:
if (ops->thaw_noirq) {
error = ops->thaw_noirq(dev);
suspend_report_result(ops->thaw_noirq, error);
}
break;
case PM_EVENT_RESTORE:
if (ops->restore_noirq) {
error = ops->restore_noirq(dev);
suspend_report_result(ops->restore_noirq, error);
}
break;
#endif /* CONFIG_HIBERNATE_CALLBACKS */
default:
error = -EINVAL;
}
if (initcall_debug) {
rettime = ktime_get();
delta = ktime_sub(rettime, calltime);
printk("initcall %s_i+ returned %d after %Ld usecs\n",
dev_name(dev), error,
(unsigned long long)ktime_to_ns(delta) >> 10);
}
return error;
}
static char *pm_verb(int event)
{
switch (event) {
case PM_EVENT_SUSPEND:
return "suspend";
case PM_EVENT_RESUME:
return "resume";
case PM_EVENT_FREEZE:
return "freeze";
case PM_EVENT_QUIESCE:
return "quiesce";
case PM_EVENT_HIBERNATE:
return "hibernate";
case PM_EVENT_THAW:
return "thaw";
case PM_EVENT_RESTORE:
return "restore";
case PM_EVENT_RECOVER:
return "recover";
default:
return "(unknown PM event)";
}
}
static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
{
dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
", may wakeup" : "");
}
static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
int error)
{
printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
dev_name(dev), pm_verb(state.event), info, error);
}
static void dpm_show_time(ktime_t starttime, pm_message_t state, char *info)
{
ktime_t calltime;
u64 usecs64;
int usecs;
calltime = ktime_get();
usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));
do_div(usecs64, NSEC_PER_USEC);
usecs = usecs64;
if (usecs == 0)
usecs = 1;
pr_info("PM: %s%s%s of devices complete after %ld.%03ld msecs\n",
info ?: "", info ? " " : "", pm_verb(state.event),
usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
}
/*------------------------- Resume routines -------------------------*/
/**
* device_resume_noirq - Execute an "early resume" callback for given device.
* @dev: Device to handle.
* @state: PM transition of the system being carried out.
*
* The driver of @dev will not receive interrupts while this function is being
* executed.
*/
static int device_resume_noirq(struct device *dev, pm_message_t state)
{
int error = 0;
TRACE_DEVICE(dev);
TRACE_RESUME(0);
if (dev->pm_domain) {
pm_dev_dbg(dev, state, "EARLY power domain ");
error = pm_noirq_op(dev, &dev->pm_domain->ops, state);
} else if (dev->type && dev->type->pm) {
pm_dev_dbg(dev, state, "EARLY type ");
error = pm_noirq_op(dev, dev->type->pm, state);
} else if (dev->class && dev->class->pm) {
pm_dev_dbg(dev, state, "EARLY class ");
error = pm_noirq_op(dev, dev->class->pm, state);
} else if (dev->bus && dev->bus->pm) {
pm_dev_dbg(dev, state, "EARLY ");
error = pm_noirq_op(dev, dev->bus->pm, state);
}
TRACE_RESUME(error);
return error;
}
/**
* dpm_resume_noirq - Execute "early resume" callbacks for non-sysdev devices.
* @state: PM transition of the system being carried out.
*
* Call the "noirq" resume handlers for all devices marked as DPM_OFF_IRQ and
* enable device drivers to receive interrupts.
*/
void dpm_resume_noirq(pm_message_t state)
{
ktime_t starttime = ktime_get();
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_noirq_list)) {
struct device *dev = to_device(dpm_noirq_list.next);
int error;
get_device(dev);
list_move_tail(&dev->power.entry, &dpm_suspended_list);
mutex_unlock(&dpm_list_mtx);
error = device_resume_noirq(dev, state);
if (error)
pm_dev_err(dev, state, " early", error);
mutex_lock(&dpm_list_mtx);
put_device(dev);
}
mutex_unlock(&dpm_list_mtx);
dpm_show_time(starttime, state, "early");
resume_device_irqs();
}
EXPORT_SYMBOL_GPL(dpm_resume_noirq);
/**
* legacy_resume - Execute a legacy (bus or class) resume callback for device.
* @dev: Device to resume.
* @cb: Resume callback to execute.
*/
static int legacy_resume(struct device *dev, int (*cb)(struct device *dev))
{
int error;
ktime_t calltime;
calltime = initcall_debug_start(dev);
error = cb(dev);
suspend_report_result(cb, error);
initcall_debug_report(dev, calltime, error);
return error;
}
/**
* device_resume - Execute "resume" callbacks for given device.
* @dev: Device to handle.
* @state: PM transition of the system being carried out.
* @async: If true, the device is being resumed asynchronously.
*/
static int device_resume(struct device *dev, pm_message_t state, bool async)
{
int error = 0;
bool put = false;
TRACE_DEVICE(dev);
TRACE_RESUME(0);
dpm_wait(dev->parent, async);
device_lock(dev);
/*
* This is a fib. But we'll allow new children to be added below
* a resumed device, even if the device hasn't been completed yet.
*/
dev->power.is_prepared = false;
if (!dev->power.is_suspended)
goto Unlock;
pm_runtime_enable(dev);
put = true;
if (dev->pm_domain) {
pm_dev_dbg(dev, state, "power domain ");
error = pm_op(dev, &dev->pm_domain->ops, state);
goto End;
}
if (dev->type && dev->type->pm) {
pm_dev_dbg(dev, state, "type ");
error = pm_op(dev, dev->type->pm, state);
goto End;
}
if (dev->class) {
if (dev->class->pm) {
pm_dev_dbg(dev, state, "class ");
error = pm_op(dev, dev->class->pm, state);
goto End;
} else if (dev->class->resume) {
pm_dev_dbg(dev, state, "legacy class ");
error = legacy_resume(dev, dev->class->resume);
goto End;
}
}
if (dev->bus) {
if (dev->bus->pm) {
pm_dev_dbg(dev, state, "");
error = pm_op(dev, dev->bus->pm, state);
} else if (dev->bus->resume) {
pm_dev_dbg(dev, state, "legacy ");
error = legacy_resume(dev, dev->bus->resume);
}
}
End:
dev->power.is_suspended = false;
Unlock:
device_unlock(dev);
complete_all(&dev->power.completion);
TRACE_RESUME(error);
if (put)
pm_runtime_put_sync(dev);
return error;
}
static void async_resume(void *data, async_cookie_t cookie)
{
struct device *dev = (struct device *)data;
int error;
error = device_resume(dev, pm_transition, true);
if (error)
pm_dev_err(dev, pm_transition, " async", error);
put_device(dev);
}
static bool is_async(struct device *dev)
{
return dev->power.async_suspend && pm_async_enabled
&& !pm_trace_is_enabled();
}
/**
* dpm_resume - Execute "resume" callbacks for non-sysdev devices.
* @state: PM transition of the system being carried out.
*
* Execute the appropriate "resume" callback for all devices whose status
* indicates that they are suspended.
*/
void dpm_resume(pm_message_t state)
{
struct device *dev;
ktime_t starttime = ktime_get();
might_sleep();
mutex_lock(&dpm_list_mtx);
pm_transition = state;
async_error = 0;
list_for_each_entry(dev, &dpm_suspended_list, power.entry) {
INIT_COMPLETION(dev->power.completion);
if (is_async(dev)) {
get_device(dev);
async_schedule(async_resume, dev);
}
}
while (!list_empty(&dpm_suspended_list)) {
dev = to_device(dpm_suspended_list.next);
get_device(dev);
if (!is_async(dev)) {
int error;
mutex_unlock(&dpm_list_mtx);
error = device_resume(dev, state, false);
if (error)
pm_dev_err(dev, state, "", error);
mutex_lock(&dpm_list_mtx);
}
if (!list_empty(&dev->power.entry))
list_move_tail(&dev->power.entry, &dpm_prepared_list);
put_device(dev);
}
mutex_unlock(&dpm_list_mtx);
async_synchronize_full();
dpm_show_time(starttime, state, NULL);
}
/**
* device_complete - Complete a PM transition for given device.
* @dev: Device to handle.
* @state: PM transition of the system being carried out.
*/
static void device_complete(struct device *dev, pm_message_t state)
{
device_lock(dev);
if (dev->pm_domain) {
pm_dev_dbg(dev, state, "completing power domain ");
if (dev->pm_domain->ops.complete)
dev->pm_domain->ops.complete(dev);
} else if (dev->type && dev->type->pm) {
pm_dev_dbg(dev, state, "completing type ");
if (dev->type->pm->complete)
dev->type->pm->complete(dev);
} else if (dev->class && dev->class->pm) {
pm_dev_dbg(dev, state, "completing class ");
if (dev->class->pm->complete)
dev->class->pm->complete(dev);
} else if (dev->bus && dev->bus->pm) {
pm_dev_dbg(dev, state, "completing ");
if (dev->bus->pm->complete)
dev->bus->pm->complete(dev);
}
device_unlock(dev);
}
/**
* dpm_complete - Complete a PM transition for all non-sysdev devices.
* @state: PM transition of the system being carried out.
*
* Execute the ->complete() callbacks for all devices whose PM status is not
* DPM_ON (this allows new devices to be registered).
*/
void dpm_complete(pm_message_t state)
{
struct list_head list;
might_sleep();
INIT_LIST_HEAD(&list);
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_prepared_list)) {
struct device *dev = to_device(dpm_prepared_list.prev);
get_device(dev);
dev->power.is_prepared = false;
list_move(&dev->power.entry, &list);
mutex_unlock(&dpm_list_mtx);
device_complete(dev, state);
mutex_lock(&dpm_list_mtx);
put_device(dev);
}
list_splice(&list, &dpm_list);
mutex_unlock(&dpm_list_mtx);
}
/**
* dpm_resume_end - Execute "resume" callbacks and complete system transition.
* @state: PM transition of the system being carried out.
*
* Execute "resume" callbacks for all devices and complete the PM transition of
* the system.
*/
void dpm_resume_end(pm_message_t state)
{
dpm_resume(state);
dpm_complete(state);
}
EXPORT_SYMBOL_GPL(dpm_resume_end);
/*------------------------- Suspend routines -------------------------*/
/**
* resume_event - Return a "resume" message for given "suspend" sleep state.
* @sleep_state: PM message representing a sleep state.
*
* Return a PM message representing the resume event corresponding to given
* sleep state.
*/
static pm_message_t resume_event(pm_message_t sleep_state)
{
switch (sleep_state.event) {
case PM_EVENT_SUSPEND:
return PMSG_RESUME;
case PM_EVENT_FREEZE:
case PM_EVENT_QUIESCE:
return PMSG_RECOVER;
case PM_EVENT_HIBERNATE:
return PMSG_RESTORE;
}
return PMSG_ON;
}
/**
* device_suspend_noirq - Execute a "late suspend" callback for given device.
* @dev: Device to handle.
* @state: PM transition of the system being carried out.
*
* The driver of @dev will not receive interrupts while this function is being
* executed.
*/
static int device_suspend_noirq(struct device *dev, pm_message_t state)
{
int error;
if (dev->pm_domain) {
pm_dev_dbg(dev, state, "LATE power domain ");
error = pm_noirq_op(dev, &dev->pm_domain->ops, state);
if (error)
return error;
} else if (dev->type && dev->type->pm) {
pm_dev_dbg(dev, state, "LATE type ");
error = pm_noirq_op(dev, dev->type->pm, state);
if (error)
return error;
} else if (dev->class && dev->class->pm) {
pm_dev_dbg(dev, state, "LATE class ");
error = pm_noirq_op(dev, dev->class->pm, state);
if (error)
return error;
} else if (dev->bus && dev->bus->pm) {
pm_dev_dbg(dev, state, "LATE ");
error = pm_noirq_op(dev, dev->bus->pm, state);
if (error)
return error;
}
return 0;
}
/**
* dpm_suspend_noirq - Execute "late suspend" callbacks for non-sysdev devices.
* @state: PM transition of the system being carried out.
*
* Prevent device drivers from receiving interrupts and call the "noirq" suspend
* handlers for all non-sysdev devices.
*/
int dpm_suspend_noirq(pm_message_t state)
{
ktime_t starttime = ktime_get();
int error = 0;
suspend_device_irqs();
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_suspended_list)) {
struct device *dev = to_device(dpm_suspended_list.prev);
get_device(dev);
mutex_unlock(&dpm_list_mtx);
error = device_suspend_noirq(dev, state);
mutex_lock(&dpm_list_mtx);
if (error) {
pm_dev_err(dev, state, " late", error);
put_device(dev);
break;
}
if (!list_empty(&dev->power.entry))
list_move(&dev->power.entry, &dpm_noirq_list);
put_device(dev);
}
mutex_unlock(&dpm_list_mtx);
if (error)
dpm_resume_noirq(resume_event(state));
else
dpm_show_time(starttime, state, "late");
return error;
}
EXPORT_SYMBOL_GPL(dpm_suspend_noirq);
/**
* legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
* @dev: Device to suspend.
* @state: PM transition of the system being carried out.
* @cb: Suspend callback to execute.
*/
static int legacy_suspend(struct device *dev, pm_message_t state,
int (*cb)(struct device *dev, pm_message_t state))
{
int error;
ktime_t calltime;
calltime = initcall_debug_start(dev);
error = cb(dev, state);
suspend_report_result(cb, error);
initcall_debug_report(dev, calltime, error);
return error;
}
/**
* device_suspend - Execute "suspend" callbacks for given device.
* @dev: Device to handle.
* @state: PM transition of the system being carried out.
* @async: If true, the device is being suspended asynchronously.
*/
static int __device_suspend(struct device *dev, pm_message_t state, bool async)
{
int error = 0;
dpm_wait_for_children(dev, async);
if (async_error)
return 0;
pm_runtime_get_noresume(dev);
if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
pm_wakeup_event(dev, 0);
if (pm_wakeup_pending()) {
pm_runtime_put_sync(dev);
async_error = -EBUSY;
return 0;
}
device_lock(dev);
if (dev->pm_domain) {
pm_dev_dbg(dev, state, "power domain ");
error = pm_op(dev, &dev->pm_domain->ops, state);
goto End;
}
if (dev->type && dev->type->pm) {
pm_dev_dbg(dev, state, "type ");
error = pm_op(dev, dev->type->pm, state);
goto End;
}
if (dev->class) {
if (dev->class->pm) {
pm_dev_dbg(dev, state, "class ");
error = pm_op(dev, dev->class->pm, state);
goto End;
} else if (dev->class->suspend) {
pm_dev_dbg(dev, state, "legacy class ");
error = legacy_suspend(dev, state, dev->class->suspend);
goto End;
}
}
if (dev->bus) {
if (dev->bus->pm) {
pm_dev_dbg(dev, state, "");
error = pm_op(dev, dev->bus->pm, state);
} else if (dev->bus->suspend) {
pm_dev_dbg(dev, state, "legacy ");
error = legacy_suspend(dev, state, dev->bus->suspend);
}
}
End:
dev->power.is_suspended = !error;
device_unlock(dev);
complete_all(&dev->power.completion);
if (error) {
pm_runtime_put_sync(dev);
async_error = error;
} else if (dev->power.is_suspended) {
__pm_runtime_disable(dev, false);
}
return error;
}
static void async_suspend(void *data, async_cookie_t cookie)
{
struct device *dev = (struct device *)data;
int error;
error = __device_suspend(dev, pm_transition, true);
if (error)
pm_dev_err(dev, pm_transition, " async", error);
put_device(dev);
}
static int device_suspend(struct device *dev)
{
INIT_COMPLETION(dev->power.completion);
if (pm_async_enabled && dev->power.async_suspend) {
get_device(dev);
async_schedule(async_suspend, dev);
return 0;
}
return __device_suspend(dev, pm_transition, false);
}
/**
* dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
* @state: PM transition of the system being carried out.
*/
int dpm_suspend(pm_message_t state)
{
ktime_t starttime = ktime_get();
int error = 0;
might_sleep();
mutex_lock(&dpm_list_mtx);
pm_transition = state;
async_error = 0;
while (!list_empty(&dpm_prepared_list)) {
struct device *dev = to_device(dpm_prepared_list.prev);
get_device(dev);
mutex_unlock(&dpm_list_mtx);
error = device_suspend(dev);
mutex_lock(&dpm_list_mtx);
if (error) {
pm_dev_err(dev, state, "", error);
put_device(dev);
break;
}
if (!list_empty(&dev->power.entry))
list_move(&dev->power.entry, &dpm_suspended_list);
put_device(dev);
if (async_error)
break;
}
mutex_unlock(&dpm_list_mtx);
async_synchronize_full();
if (!error)
error = async_error;
if (!error)
dpm_show_time(starttime, state, NULL);
return error;
}
/**
* device_prepare - Prepare a device for system power transition.
* @dev: Device to handle.
* @state: PM transition of the system being carried out.
*
* Execute the ->prepare() callback(s) for given device. No new children of the
* device may be registered after this function has returned.
*/
static int device_prepare(struct device *dev, pm_message_t state)
{
int error = 0;
device_lock(dev);
if (dev->pm_domain) {
pm_dev_dbg(dev, state, "preparing power domain ");
if (dev->pm_domain->ops.prepare)
error = dev->pm_domain->ops.prepare(dev);
suspend_report_result(dev->pm_domain->ops.prepare, error);
if (error)
goto End;
} else if (dev->type && dev->type->pm) {
pm_dev_dbg(dev, state, "preparing type ");
if (dev->type->pm->prepare)
error = dev->type->pm->prepare(dev);
suspend_report_result(dev->type->pm->prepare, error);
if (error)
goto End;
} else if (dev->class && dev->class->pm) {
pm_dev_dbg(dev, state, "preparing class ");
if (dev->class->pm->prepare)
error = dev->class->pm->prepare(dev);
suspend_report_result(dev->class->pm->prepare, error);
if (error)
goto End;
} else if (dev->bus && dev->bus->pm) {
pm_dev_dbg(dev, state, "preparing ");
if (dev->bus->pm->prepare)
error = dev->bus->pm->prepare(dev);
suspend_report_result(dev->bus->pm->prepare, error);
}
End:
device_unlock(dev);
return error;
}
/**
* dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
* @state: PM transition of the system being carried out.
*
* Execute the ->prepare() callback(s) for all devices.
*/
int dpm_prepare(pm_message_t state)
{
int error = 0;
might_sleep();
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_list)) {
struct device *dev = to_device(dpm_list.next);
get_device(dev);
mutex_unlock(&dpm_list_mtx);
error = device_prepare(dev, state);
mutex_lock(&dpm_list_mtx);
if (error) {
if (error == -EAGAIN) {
put_device(dev);
error = 0;
continue;
}
printk(KERN_INFO "PM: Device %s not prepared "
"for power transition: code %d\n",
dev_name(dev), error);
put_device(dev);
break;
}
dev->power.is_prepared = true;
if (!list_empty(&dev->power.entry))
list_move_tail(&dev->power.entry, &dpm_prepared_list);
put_device(dev);
}
mutex_unlock(&dpm_list_mtx);
return error;
}
/**
* dpm_suspend_start - Prepare devices for PM transition and suspend them.
* @state: PM transition of the system being carried out.
*
* Prepare all non-sysdev devices for system PM transition and execute "suspend"
* callbacks for them.
*/
int dpm_suspend_start(pm_message_t state)
{
int error;
error = dpm_prepare(state);
if (!error)
error = dpm_suspend(state);
return error;
}
EXPORT_SYMBOL_GPL(dpm_suspend_start);
void __suspend_report_result(const char *function, void *fn, int ret)
{
if (ret)
printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
}
EXPORT_SYMBOL_GPL(__suspend_report_result);
/**
* device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
* @dev: Device to wait for.
* @subordinate: Device that needs to wait for @dev.
*/
int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
{
dpm_wait(dev, subordinate->power.async_suspend);
return async_error;
}
EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
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