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linux-kernel-test/drivers/base/power/main.c
Rafael J. Wysocki 9659cc0678 PM: Make system-wide PM and runtime PM treat subsystems consistently 
The code handling system-wide power transitions (eg. suspend-to-RAM)
can in theory execute callbacks provided by the device's bus type,
device type and class in each phase of the power transition.  In
turn, the runtime PM core code only calls one of those callbacks at
a time, preferring bus type callbacks to device type or class
callbacks and device type callbacks to class callbacks.

It seems reasonable to make them both behave in the same way in that
respect.  Moreover, even though a device may belong to two subsystems
(eg. bus type and device class) simultaneously, in practice power
management callbacks for system-wide power transitions are always
provided by only one of them (ie. if the bus type callbacks are
defined, the device class ones are not and vice versa).  Thus it is
possible to modify the code handling system-wide power transitions
so that it follows the core runtime PM code (ie. treats the
subsystem callbacks as mutually exclusive).

On the other hand, the core runtime PM code will choose to execute,
for example, a runtime suspend callback provided by the device type
even if the bus type's struct dev_pm_ops object exists, but the
runtime_suspend pointer in it happens to be NULL.  This is confusing,
because it may lead to the execution of callbacks from different
subsystems during different operations (eg. the bus type suspend
callback may be executed during runtime suspend of the device, while
the device type callback will be executed during system suspend).

Make all of the power management code treat subsystem callbacks in
a consistent way, such that:
(1) If the device's type is defined (eg. dev->type is not NULL)
    and its pm pointer is not NULL, the callbacks from dev->type->pm
    will be used.
(2) If dev->type is NULL or dev->type->pm is NULL, but the device's
    class is defined (eg. dev->class is not NULL) and its pm pointer
    is not NULL, the callbacks from dev->class->pm will be used.
(3) If dev->type is NULL or dev->type->pm is NULL and dev->class is
    NULL or dev->class->pm is NULL, the callbacks from dev->bus->pm
    will be used provided that both dev->bus and dev->bus->pm are
    not NULL.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>
Reasoning-sounds-sane-to: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-15 00:43:17 +01:00

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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.in_suspend = 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);
}
/**
* 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.in_suspend)
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_HIBERNATION
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_HIBERNATION */
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_HIBERNATION
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_HIBERNATION */
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->pwr_domain) {
pm_dev_dbg(dev, state, "EARLY power domain ");
pm_noirq_op(dev, &dev->pwr_domain->ops, state);
}
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;
TRACE_DEVICE(dev);
TRACE_RESUME(0);
dpm_wait(dev->parent, async);
device_lock(dev);
dev->power.in_suspend = false;
if (dev->pwr_domain) {
pm_dev_dbg(dev, state, "power domain ");
pm_op(dev, &dev->pwr_domain->ops, state);
}
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:
device_unlock(dev);
complete_all(&dev->power.completion);
TRACE_RESUME(error);
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.
*/
static void dpm_resume(pm_message_t state)
{
struct device *dev;
ktime_t starttime = ktime_get();
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->pwr_domain && dev->pwr_domain->ops.complete) {
pm_dev_dbg(dev, state, "completing power domain ");
dev->pwr_domain->ops.complete(dev);
}
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).
*/
static void dpm_complete(pm_message_t state)
{
struct list_head list;
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.in_suspend = 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)
{
might_sleep();
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->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;
}
if (dev->pwr_domain) {
pm_dev_dbg(dev, state, "LATE power domain ");
pm_noirq_op(dev, &dev->pwr_domain->ops, state);
}
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);
device_lock(dev);
if (async_error)
goto End;
if (pm_wakeup_pending()) {
async_error = -EBUSY;
goto End;
}
if (dev->type && dev->type->pm) {
pm_dev_dbg(dev, state, "type ");
error = pm_op(dev, dev->type->pm, state);
goto Domain;
}
if (dev->class) {
if (dev->class->pm) {
pm_dev_dbg(dev, state, "class ");
error = pm_op(dev, dev->class->pm, state);
goto Domain;
} else if (dev->class->suspend) {
pm_dev_dbg(dev, state, "legacy class ");
error = legacy_suspend(dev, state, dev->class->suspend);
goto Domain;
}
}
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);
}
}
Domain:
if (!error && dev->pwr_domain) {
pm_dev_dbg(dev, state, "power domain ");
pm_op(dev, &dev->pwr_domain->ops, state);
}
End:
device_unlock(dev);
complete_all(&dev->power.completion);
if (error)
async_error = error;
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.
*/
static int dpm_suspend(pm_message_t state)
{
ktime_t starttime = ktime_get();
int error = 0;
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->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);
if (error)
goto End;
}
if (dev->pwr_domain && dev->pwr_domain->ops.prepare) {
pm_dev_dbg(dev, state, "preparing power domain ");
dev->pwr_domain->ops.prepare(dev);
}
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.
*/
static int dpm_prepare(pm_message_t state)
{
int error = 0;
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);
pm_runtime_get_noresume(dev);
if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
pm_wakeup_event(dev, 0);
pm_runtime_put_sync(dev);
error = pm_wakeup_pending() ?
-EBUSY : 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.in_suspend = 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;
might_sleep();
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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