text: /*
   * 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/export.h>
  #include <linux/mutex.h>
  #include <linux/pm.h>
  #include <linux/pm_runtime.h>
  #include <linux/pm-trace.h>
  #include <linux/pm_wakeirq.h>
  #include <linux/interrupt.h>
  #include <linux/sched.h>
  #include <linux/sched/debug.h>
  #include <linux/async.h>
  #include <linux/suspend.h>
  #include <trace/events/power.h>
  #include <linux/cpufreq.h>
  #include <linux/cpuidle.h>
  #include <linux/timer.h>
  #include <linux/wakeup_reason.h>
  
  #if defined CONFIG_LOG_JANK
  #include <huawei_platform/log/log_jank.h>
  #endif
  
  #include "../base.h"
  #include "power.h"
  
  typedef int (*pm_callback_t)(struct device *);
  
  /*
   * 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);
  static LIST_HEAD(dpm_prepared_list);
  static LIST_HEAD(dpm_suspended_list);
  static LIST_HEAD(dpm_late_early_list);
  static LIST_HEAD(dpm_noirq_list);
  
  struct suspend_stats suspend_stats;
  static DEFINE_MUTEX(dpm_list_mtx);
  static pm_message_t pm_transition;
  
  static int async_error;
  
  static const 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)";
  	}
  }
  
  /**
   * device_pm_sleep_init - Initialize system suspend-related device fields.
   * @dev: Device object being initialized.
   */
  void device_pm_sleep_init(struct device *dev)
  {
  	dev->power.is_prepared = false;
  	dev->power.is_suspended = false;
  	dev->power.is_noirq_suspended = false;
  	dev->power.is_late_suspended = false;
  	init_completion(&dev->power.completion);
  	complete_all(&dev->power.completion);
  	dev->power.wakeup = NULL;
  	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)
  {
  	/* Skip PM setup/initialization. */
  	if (device_pm_not_required(dev))
  		return;
  
  	pr_debug("PM: Adding info for %s:%s\n",
  		 dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
  	device_pm_check_callbacks(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);
  	dev->power.in_dpm_list = true;
  	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)
  {
  	if (device_pm_not_required(dev))
  		return;
  
  	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);
  	dev->power.in_dpm_list = false;
  	mutex_unlock(&dpm_list_mtx);
  	device_wakeup_disable(dev);
  	pm_runtime_remove(dev);
  	device_pm_check_callbacks(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 = 0;
  
  	if (pm_print_times_enabled) {
  		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();
  	}
  
  	return calltime;
  }
  
  static void initcall_debug_report(struct device *dev, ktime_t calltime,
  				  int error, pm_message_t state,
  				  const char *info)
  {
  	ktime_t rettime;
  	s64 nsecs;
  
  	rettime = ktime_get();
  	nsecs = (s64) ktime_to_ns(ktime_sub(rettime, calltime));
  
  	if (pm_print_times_enabled) {
  		pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
  			error, (unsigned long long)nsecs >> 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);
  }
  
  static void dpm_wait_for_suppliers(struct device *dev, bool async)
  {
  	struct device_link *link;
  	int idx;
  
  	idx = device_links_read_lock();
  
  	/*
  	 * If the supplier goes away right after we've checked the link to it,
  	 * we'll wait for its completion to change the state, but that's fine,
  	 * because the only things that will block as a result are the SRCU
  	 * callbacks freeing the link objects for the links in the list we're
  	 * walking.
  	 */
  	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
  		if (READ_ONCE(link->status) != DL_STATE_DORMANT)
  			dpm_wait(link->supplier, async);
  
  	device_links_read_unlock(idx);
  }
  
  static void dpm_wait_for_superior(struct device *dev, bool async)
  {
  	dpm_wait(dev->parent, async);
  	dpm_wait_for_suppliers(dev, async);
  }
  
  static void dpm_wait_for_consumers(struct device *dev, bool async)
  {
  	struct device_link *link;
  	int idx;
  
  	idx = device_links_read_lock();
  
  	/*
  	 * The status of a device link can only be changed from "dormant" by a
  	 * probe, but that cannot happen during system suspend/resume.  In
  	 * theory it can change to "dormant" at that time, but then it is
  	 * reasonable to wait for the target device anyway (eg. if it goes
  	 * away, it's better to wait for it to go away completely and then
  	 * continue instead of trying to continue in parallel with its
  	 * unregistration).
  	 */
  	list_for_each_entry_rcu(link, &dev->links.consumers, s_node)
  		if (READ_ONCE(link->status) != DL_STATE_DORMANT)
  			dpm_wait(link->consumer, async);
  
  	device_links_read_unlock(idx);
  }
  
  static void dpm_wait_for_subordinate(struct device *dev, bool async)
  {
  	dpm_wait_for_children(dev, async);
  	dpm_wait_for_consumers(dev, async);
  }
  
  /**
   * pm_op - Return the PM operation appropriate for given PM event.
   * @ops: PM operations to choose from.
   * @state: PM transition of the system being carried out.
   */
  static pm_callback_t pm_op(const struct dev_pm_ops *ops, pm_message_t state)
  {
  	switch (state.event) {
  #ifdef CONFIG_SUSPEND
  	case PM_EVENT_SUSPEND:
  		return ops->suspend;
  	case PM_EVENT_RESUME:
  		return ops->resume;
  #endif /* CONFIG_SUSPEND */
  #ifdef CONFIG_HIBERNATE_CALLBACKS
  	case PM_EVENT_FREEZE:
  	case PM_EVENT_QUIESCE:
  		return ops->freeze;
  	case PM_EVENT_HIBERNATE:
  		return ops->poweroff;
  	case PM_EVENT_THAW:
  	case PM_EVENT_RECOVER:
  		return ops->thaw;
  		break;
  	case PM_EVENT_RESTORE:
  		return ops->restore;
  #endif /* CONFIG_HIBERNATE_CALLBACKS */
  	}
  
  	return NULL;
  }
  
  /**
   * pm_late_early_op - Return the PM operation appropriate for given PM event.
   * @ops: PM operations to choose from.
   * @state: PM transition of the system being carried out.
   *
   * Runtime PM is disabled for @dev while this function is being executed.
   */
  static pm_callback_t pm_late_early_op(const struct dev_pm_ops *ops,
  				      pm_message_t state)
  {
  	switch (state.event) {
  #ifdef CONFIG_SUSPEND
  	case PM_EVENT_SUSPEND:
  		return ops->suspend_late;
  	case PM_EVENT_RESUME:
  		return ops->resume_early;
  #endif /* CONFIG_SUSPEND */
  #ifdef CONFIG_HIBERNATE_CALLBACKS
  	case PM_EVENT_FREEZE:
  	case PM_EVENT_QUIESCE:
  		return ops->freeze_late;
  	case PM_EVENT_HIBERNATE:
  		return ops->poweroff_late;
  	case PM_EVENT_THAW:
  	case PM_EVENT_RECOVER:
  		return ops->thaw_early;
  	case PM_EVENT_RESTORE:
  		return ops->restore_early;
  #endif /* CONFIG_HIBERNATE_CALLBACKS */
  	}
  
  	return NULL;
  }
  
  /**
   * pm_noirq_op - Return the PM operation appropriate for given PM event.
   * @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 pm_callback_t pm_noirq_op(const struct dev_pm_ops *ops, pm_message_t state)
  {
  	switch (state.event) {
  #ifdef CONFIG_SUSPEND
  	case PM_EVENT_SUSPEND:
  		return ops->suspend_noirq;
  	case PM_EVENT_RESUME:
  		return ops->resume_noirq;
  #endif /* CONFIG_SUSPEND */
  #ifdef CONFIG_HIBERNATE_CALLBACKS
  	case PM_EVENT_FREEZE:
  	case PM_EVENT_QUIESCE:
  		return ops->freeze_noirq;
  	case PM_EVENT_HIBERNATE:
  		return ops->poweroff_noirq;
  	case PM_EVENT_THAW:
  	case PM_EVENT_RECOVER:
  		return ops->thaw_noirq;
  	case PM_EVENT_RESTORE:
  		return ops->restore_noirq;
  #endif /* CONFIG_HIBERNATE_CALLBACKS */
  	}
  
  	return NULL;
  }
  
  static void pm_dev_dbg(struct device *dev, pm_message_t state, const 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, const 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, int error,
  			  const 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;
  
  	pm_pr_dbg("%s%s%s of devices %s after %ld.%03ld msecs\n",
  		  info ?: "", info ? " " : "", pm_verb(state.event),
  		  error ? "aborted" : "complete",
  		  usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
  
  	#if defined CONFIG_LOG_JANK
  	if (PM_EVENT_RESUME == state.event)
  		  LOG_JANK_D(JLID_KERNEL_PM_DEEPSLEEP_WAKEUP,
  		  "%s: %ld.%03ld msecs",
  		  "JL_KERNEL_PM_DEEPSLEEP_WAKEUP",
  		  usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
  	#endif
  }
  
  static int dpm_run_callback(pm_callback_t cb, struct device *dev,
  			    pm_message_t state, const char *info)
  {
  	ktime_t calltime;
  	int error;
  
  	if (!cb)
  		return 0;
  
  	calltime = initcall_debug_start(dev);
  
  	pm_dev_dbg(dev, state, info);
  	trace_device_pm_callback_start(dev, info, state.event);
  	error = cb(dev);
  	trace_device_pm_callback_end(dev, error);
  	suspend_report_result(cb, error);
  
  	initcall_debug_report(dev, calltime, error, state, info);
  
  	return error;
  }
  
  #ifdef CONFIG_DPM_WATCHDOG
  struct dpm_watchdog {
  	struct device		*dev;
  	struct task_struct	*tsk;
  	struct timer_list	timer;
  };
  
  #define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \
  	struct dpm_watchdog wd
  
  /**
   * dpm_watchdog_handler - Driver suspend / resume watchdog handler.
   * @data: Watchdog object address.
   *
   * Called when a driver has timed out suspending or resuming.
   * There's not much we can do here to recover so panic() to
   * capture a crash-dump in pstore.
   */
  static void dpm_watchdog_handler(unsigned long data)
  {
  	struct dpm_watchdog *wd = (void *)data;
  
  	dev_emerg(wd->dev, "**** DPM device timeout ****\n");
  	show_stack(wd->tsk, NULL);
  	panic("%s %s: unrecoverable failure\n",
  		dev_driver_string(wd->dev), dev_name(wd->dev));
  }
  
  /**
   * dpm_watchdog_set - Enable pm watchdog for given device.
   * @wd: Watchdog. Must be allocated on the stack.
   * @dev: Device to handle.
   */
  static void dpm_watchdog_set(struct dpm_watchdog *wd, struct device *dev)
  {
  	struct timer_list *timer = &wd->timer;
  
  	wd->dev = dev;
  	wd->tsk = current;
  
  	init_timer_on_stack(timer);
  	/* use same timeout value for both suspend and resume */
  	timer->expires = jiffies + HZ * CONFIG_DPM_WATCHDOG_TIMEOUT;
  	timer->function = dpm_watchdog_handler;
  	timer->data = (unsigned long)wd;
  	add_timer(timer);
  }
  
  /**
   * dpm_watchdog_clear - Disable suspend/resume watchdog.
   * @wd: Watchdog to disable.
   */
  static void dpm_watchdog_clear(struct dpm_watchdog *wd)
  {
  	struct timer_list *timer = &wd->timer;
  
  	del_timer_sync(timer);
  	destroy_timer_on_stack(timer);
  }
  #else
  #define DECLARE_DPM_WATCHDOG_ON_STACK(wd)
  #define dpm_watchdog_set(x, y)
  #define dpm_watchdog_clear(x)
  #endif
  
  /*------------------------- 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.
   * @async: If true, the device is being resumed asynchronously.
   *
   * 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, bool async)
  {
  	pm_callback_t callback = NULL;
  	const char *info = NULL;
  	int error = 0;
  
  	TRACE_DEVICE(dev);
  	TRACE_RESUME(0);
  
  	if (dev->power.syscore || dev->power.direct_complete)
  		goto Out;
  
  	if (!dev->power.is_noirq_suspended)
  		goto Out;
  
  	dpm_wait_for_superior(dev, async);
  
  	if (dev->pm_domain) {
  		info = "noirq power domain ";
  		callback = pm_noirq_op(&dev->pm_domain->ops, state);
  	} else if (dev->type && dev->type->pm) {
  		info = "noirq type ";
  		callback = pm_noirq_op(dev->type->pm, state);
  	} else if (dev->class && dev->class->pm) {
  		info = "noirq class ";
  		callback = pm_noirq_op(dev->class->pm, state);
  	} else if (dev->bus && dev->bus->pm) {
  		info = "noirq bus ";
  		callback = pm_noirq_op(dev->bus->pm, state);
  	}
  
  	if (!callback && dev->driver && dev->driver->pm) {
  		info = "noirq driver ";
  		callback = pm_noirq_op(dev->driver->pm, state);
  	}
  
  	error = dpm_run_callback(callback, dev, state, info);
  	dev->power.is_noirq_suspended = false;
  
   Out:
  	complete_all(&dev->power.completion);
  	TRACE_RESUME(error);
  	return error;
  }
  
  static bool is_async(struct device *dev)
  {
  	return dev->power.async_suspend && pm_async_enabled
  		&& !pm_trace_is_enabled();
  }
  
  static void async_resume_noirq(void *data, async_cookie_t cookie)
  {
  	struct device *dev = (struct device *)data;
  	int error;
  
  	error = device_resume_noirq(dev, pm_transition, true);
  	if (error)
  		pm_dev_err(dev, pm_transition, " async", error);
  
  	put_device(dev);
  }
  
  void dpm_noirq_resume_devices(pm_message_t state)
  {
  	struct device *dev;
  	ktime_t starttime = ktime_get();
  
  	trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, true);
  	mutex_lock(&dpm_list_mtx);
  	pm_transition = state;
  
  	/*
  	 * Advanced the async threads upfront,
  	 * in case the starting of async threads is
  	 * delayed by non-async resuming devices.
  	 */
  	list_for_each_entry(dev, &dpm_noirq_list, power.entry) {
  		reinit_completion(&dev->power.completion);
  		if (is_async(dev)) {
  			get_device(dev);
  			async_schedule(async_resume_noirq, dev);
  		}
  	}
  
  	while (!list_empty(&dpm_noirq_list)) {
  		dev = to_device(dpm_noirq_list.next);
  		get_device(dev);
  		list_move_tail(&dev->power.entry, &dpm_late_early_list);
  		mutex_unlock(&dpm_list_mtx);
  
  		if (!is_async(dev)) {
  			int error;
  
  			error = device_resume_noirq(dev, state, false);
  			if (error) {
  				suspend_stats.failed_resume_noirq++;
  				dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
  				dpm_save_failed_dev(dev_name(dev));
  				pm_dev_err(dev, state, " noirq", error);
  			}
  		}
  
  		mutex_lock(&dpm_list_mtx);
  		put_device(dev);
  	}
  	mutex_unlock(&dpm_list_mtx);
  	async_synchronize_full();
  	dpm_show_time(starttime, state, 0, "noirq");
  	trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, false);
  }
  
  void dpm_noirq_end(void)
  {
  	resume_device_irqs();
  	device_wakeup_disarm_wake_irqs();
  	cpuidle_resume();
  }
  
  /**
   * dpm_resume_noirq - Execute "noirq resume" callbacks for all devices.
   * @state: PM transition of the system being carried out.
   *
   * Invoke the "noirq" resume callbacks for all devices in dpm_noirq_list and
   * allow device drivers' interrupt handlers to be called.
   */
  void dpm_resume_noirq(pm_message_t state)
  {
  	dpm_noirq_resume_devices(state);
  	dpm_noirq_end();
  }
  
  /**
   * device_resume_early - Execute an "early resume" callback 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.
   *
   * Runtime PM is disabled for @dev while this function is being executed.
   */
  static int device_resume_early(struct device *dev, pm_message_t state, bool async)
  {
  	pm_callback_t callback = NULL;
  	const char *info = NULL;
  	int error = 0;
  
  	TRACE_DEVICE(dev);
  	TRACE_RESUME(0);
  
  	if (dev->power.syscore || dev->power.direct_complete)
  		goto Out;
  
  	if (!dev->power.is_late_suspended)
  		goto Out;
  
  	dpm_wait_for_superior(dev, async);
  
  	if (dev->pm_domain) {
  		info = "early power domain ";
  		callback = pm_late_early_op(&dev->pm_domain->ops, state);
  	} else if (dev->type && dev->type->pm) {
  		info = "early type ";
  		callback = pm_late_early_op(dev->type->pm, state);
  	} else if (dev->class && dev->class->pm) {
  		info = "early class ";
  		callback = pm_late_early_op(dev->class->pm, state);
  	} else if (dev->bus && dev->bus->pm) {
  		info = "early bus ";
  		callback = pm_late_early_op(dev->bus->pm, state);
  	}
  
  	if (!callback && dev->driver && dev->driver->pm) {
  		info = "early driver ";
  		callback = pm_late_early_op(dev->driver->pm, state);
  	}
  
  	error = dpm_run_callback(callback, dev, state, info);
  	dev->power.is_late_suspended = false;
  
   Out:
  	TRACE_RESUME(error);
  
  	pm_runtime_enable(dev);
  	complete_all(&dev->power.completion);
  	return error;
  }
  
  static void async_resume_early(void *data, async_cookie_t cookie)
  {
  	struct device *dev = (struct device *)data;
  	int error;
  
  	error = device_resume_early(dev, pm_transition, true);
  	if (error)
  		pm_dev_err(dev, pm_transition, " async", error);
  
  	put_device(dev);
  }
  
  /**
   * dpm_resume_early - Execute "early resume" callbacks for all devices.
   * @state: PM transition of the system being carried out.
   */
  void dpm_resume_early(pm_message_t state)
  {
  	struct device *dev;
  	ktime_t starttime = ktime_get();
  
  	trace_suspend_resume(TPS("dpm_resume_early"), state.event, true);
  	mutex_lock(&dpm_list_mtx);
  	pm_transition = state;
  
  	/*
  	 * Advanced the async threads upfront,
  	 * in case the starting of async threads is
  	 * delayed by non-async resuming devices.
  	 */
  	list_for_each_entry(dev, &dpm_late_early_list, power.entry) {
  		reinit_completion(&dev->power.completion);
  		if (is_async(dev)) {
  			get_device(dev);
  			async_schedule(async_resume_early, dev);
  		}
  	}
  
  	while (!list_empty(&dpm_late_early_list)) {
  		dev = to_device(dpm_late_early_list.next);
  		get_device(dev);
  		list_move_tail(&dev->power.entry, &dpm_suspended_list);
  		mutex_unlock(&dpm_list_mtx);
  
  		if (!is_async(dev)) {
  			int error;
  
  			error = device_resume_early(dev, state, false);
  			if (error) {
  				suspend_stats.failed_resume_early++;
  				dpm_save_failed_step(SUSPEND_RESUME_EARLY);
  				dpm_save_failed_dev(dev_name(dev));
  				pm_dev_err(dev, state, " early", error);
  			}
  		}
  		mutex_lock(&dpm_list_mtx);
  		put_device(dev);
  	}
  	mutex_unlock(&dpm_list_mtx);
  	async_synchronize_full();
  	dpm_show_time(starttime, state, 0, "early");
  	trace_suspend_resume(TPS("dpm_resume_early"), state.event, false);
  }
  
  /**
   * dpm_resume_start - Execute "noirq" and "early" device callbacks.
   * @state: PM transition of the system being carried out.
   */
  void dpm_resume_start(pm_message_t state)
  {
  	dpm_resume_noirq(state);
  	dpm_resume_early(state);
  }
  EXPORT_SYMBOL_GPL(dpm_resume_start);
  
  /**
   * 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)
  {
  	pm_callback_t callback = NULL;
  	const char *info = NULL;
  	int error = 0;
  	DECLARE_DPM_WATCHDOG_ON_STACK(wd);
  
  	TRACE_DEVICE(dev);
  	TRACE_RESUME(0);
  
  	if (dev->power.syscore)
  		goto Complete;
  
  	if (dev->power.direct_complete) {
  		/* Match the pm_runtime_disable() in __device_suspend(). */
  		pm_runtime_enable(dev);
  		goto Complete;
  	}
  
  	dpm_wait_for_superior(dev, async);
  	dpm_watchdog_set(&wd, dev);
  	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;
  
  	if (dev->pm_domain) {
  		info = "power domain ";
  		callback = pm_op(&dev->pm_domain->ops, state);
  		goto Driver;
  	}
  
  	if (dev->type && dev->type->pm) {
  		info = "type ";
  		callback = pm_op(dev->type->pm, state);
  		goto Driver;
  	}
  
  	if (dev->class) {
  		if (dev->class->pm) {
  			info = "class ";
  			callback = pm_op(dev->class->pm, state);
  			goto Driver;
  		} else if (dev->class->resume) {
  			info = "legacy class ";
  			callback = dev->class->resume;
  			goto End;
  		}
  	}
  
  	if (dev->bus) {
  		if (dev->bus->pm) {
  			info = "bus ";
  			callback = pm_op(dev->bus->pm, state);
  		} else if (dev->bus->resume) {
  			info = "legacy bus ";
  			callback = dev->bus->resume;
  			goto End;
  		}
  	}
  
   Driver:
  	if (!callback && dev->driver && dev->driver->pm) {
  		info = "driver ";
  		callback = pm_op(dev->driver->pm, state);
  	}
  
   End:
  	error = dpm_run_callback(callback, dev, state, info);
  	dev->power.is_suspended = false;
  
   Unlock:
  	device_unlock(dev);
  	dpm_watchdog_clear(&wd);
  
   Complete:
  	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);
  }
  
  /**
   * 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();
  
  	trace_suspend_resume(TPS("dpm_resume"), state.event, true);
  	might_sleep();
  
  	mutex_lock(&dpm_list_mtx);
  	pm_transition = state;
  	async_error = 0;
  
  	list_for_each_entry(dev, &dpm_suspended_list, power.entry) {
  		reinit_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) {
  				suspend_stats.failed_resume++;
  				dpm_save_failed_step(SUSPEND_RESUME);
  				dpm_save_failed_dev(dev_name(dev));
  				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, 0, NULL);
  
  	cpufreq_resume();
  	trace_suspend_resume(TPS("dpm_resume"), state.event, false);
  }
  
  /**
   * 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)
  {
  	void (*callback)(struct device *) = NULL;
  	const char *info = NULL;
  
  	if (dev->power.syscore)
  		return;
  
  	device_lock(dev);
  
  	if (dev->pm_domain) {
  		info = "completing power domain ";
  		callback = dev->pm_domain->ops.complete;
  	} else if (dev->type && dev->type->pm) {
  		info = "completing type ";
  		callback = dev->type->pm->complete;
  	} else if (dev->class && dev->class->pm) {
  		info = "completing class ";
  		callback = dev->class->pm->complete;
  	} else if (dev->bus && dev->bus->pm) {
  		info = "completing bus ";
  		callback = dev->bus->pm->complete;
  	}
  
  	if (!callback && dev->driver && dev->driver->pm) {
  		info = "completing driver ";
  		callback = dev->driver->pm->complete;
  	}
  
  	if (callback) {
  		pm_dev_dbg(dev, state, info);
  		callback(dev);
  	}
  
  	device_unlock(dev);
  
  	pm_runtime_put(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;
  
  	trace_suspend_resume(TPS("dpm_complete"), state.event, true);
  	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);
  
  		trace_device_pm_callback_start(dev, "", state.event);
  		device_complete(dev, state);
  		trace_device_pm_callback_end(dev, 0);
  
  		mutex_lock(&dpm_list_mtx);
  		put_device(dev);
  	}
  	list_splice(&list, &dpm_list);
  	mutex_unlock(&dpm_list_mtx);
  
  	/* Allow device probing and trigger re-probing of deferred devices */
  	device_unblock_probing();
  	trace_suspend_resume(TPS("dpm_complete"), state.event, false);
  }
  
  /**
   * 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.
   * @async: If true, the device is being suspended asynchronously.
   *
   * 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, bool async)
  {
  	pm_callback_t callback = NULL;
  	const char *info = NULL;
  	int error = 0;
  
  	TRACE_DEVICE(dev);
  	TRACE_SUSPEND(0);
  
  	dpm_wait_for_subordinate(dev, async);
  
  	if (async_error)
  		goto Complete;
  
  	if (pm_wakeup_pending()) {
  		async_error = -EBUSY;
  		goto Complete;
  	}
  
  	if (dev->power.syscore || dev->power.direct_complete)
  		goto Complete;
  
  	if (dev->pm_domain) {
  		info = "noirq power domain ";
  		callback = pm_noirq_op(&dev->pm_domain->ops, state);
  	} else if (dev->type && dev->type->pm) {
  		info = "noirq type ";
  		callback = pm_noirq_op(dev->type->pm, state);
  	} else if (dev->class && dev->class->pm) {
  		info = "noirq class ";
  		callback = pm_noirq_op(dev->class->pm, state);
  	} else if (dev->bus && dev->bus->pm) {
  		info = "noirq bus ";
  		callback = pm_noirq_op(dev->bus->pm, state);
  	}
  
  	if (!callback && dev->driver && dev->driver->pm) {
  		info = "noirq driver ";
  		callback = pm_noirq_op(dev->driver->pm, state);
  	}
  
  	error = dpm_run_callback(callback, dev, state, info);
  	if (!error)
  		dev->power.is_noirq_suspended = true;
  	else
  		async_error = error;
  
  Complete:
  	complete_all(&dev->power.completion);
  	TRACE_SUSPEND(error);
  	return error;
  }
  
  static void async_suspend_noirq(void *data, async_cookie_t cookie)
  {
  	struct device *dev = (struct device *)data;
  	int error;
  
  	error = __device_suspend_noirq(dev, pm_transition, true);
  	if (error) {
  		dpm_save_failed_dev(dev_name(dev));
  		pm_dev_err(dev, pm_transition, " async", error);
  	}
  
  	put_device(dev);
  }
  
  static int device_suspend_noirq(struct device *dev)
  {
  	reinit_completion(&dev->power.completion);
  
  	if (is_async(dev)) {
  		get_device(dev);
  		async_schedule(async_suspend_noirq, dev);
  		return 0;
  	}
  	return __device_suspend_noirq(dev, pm_transition, false);
  }
  
  void dpm_noirq_begin(void)
  {
  	cpuidle_pause();
  	device_wakeup_arm_wake_irqs();
  	suspend_device_irqs();
  }
  
  int dpm_noirq_suspend_devices(pm_message_t state)
  {
  	ktime_t starttime = ktime_get();
  	int error = 0;
  
  	trace_suspend_resume(TPS("dpm_suspend_noirq"), state.event, true);
  	mutex_lock(&dpm_list_mtx);
  	pm_transition = state;
  	async_error = 0;
  
  	while (!list_empty(&dpm_late_early_list)) {
  		struct device *dev = to_device(dpm_late_early_list.prev);
  
  		get_device(dev);
  		mutex_unlock(&dpm_list_mtx);
  
  		error = device_suspend_noirq(dev);
  
  		mutex_lock(&dpm_list_mtx);
  		if (error) {
  			pm_dev_err(dev, state, " noirq", error);
  			dpm_save_failed_dev(dev_name(dev));
  			put_device(dev);
  			break;
  		}
  		if (!list_empty(&dev->power.entry))
  			list_move(&dev->power.entry, &dpm_noirq_list);
  		put_device(dev);
  
  		if (async_error)
  			break;
  	}
  	mutex_unlock(&dpm_list_mtx);
  	async_synchronize_full();
  	if (!error)
  		error = async_error;
  
  	if (error) {
  		suspend_stats.failed_suspend_noirq++;
  		dpm_save_failed_step(SUSPEND_SUSPEND_NOIRQ);
  	}
  	dpm_show_time(starttime, state, error, "noirq");
  	trace_suspend_resume(TPS("dpm_suspend_noirq"), state.event, false);
  	return error;
  }
  
  /**
   * dpm_suspend_noirq - Execute "noirq suspend" callbacks for all devices.
   * @state: PM transition of the system being carried out.
   *
   * Prevent device drivers' interrupt handlers from being called and invoke
   * "noirq" suspend callbacks for all non-sysdev devices.
   */
  int dpm_suspend_noirq(pm_message_t state)
  {
  	int ret;
  
  	dpm_noirq_begin();
  	ret = dpm_noirq_suspend_devices(state);
  	if (ret)
  		dpm_resume_noirq(resume_event(state));
  
  	return ret;
  }
  
  /**
   * device_suspend_late - Execute a "late suspend" callback 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.
   *
   * Runtime PM is disabled for @dev while this function is being executed.
   */
  static int __device_suspend_late(struct device *dev, pm_message_t state, bool async)
  {
  	pm_callback_t callback = NULL;
  	const char *info = NULL;
  	int error = 0;
  
  	TRACE_DEVICE(dev);
  	TRACE_SUSPEND(0);
  
  	__pm_runtime_disable(dev, false);
  
  	dpm_wait_for_subordinate(dev, async);
  
  	if (async_error)
  		goto Complete;
  
  	if (pm_wakeup_pending()) {
  		async_error = -EBUSY;
  		goto Complete;
  	}
  
  	if (dev->power.syscore || dev->power.direct_complete)
  		goto Complete;
  
  	if (dev->pm_domain) {
  		info = "late power domain ";
  		callback = pm_late_early_op(&dev->pm_domain->ops, state);
  	} else if (dev->type && dev->type->pm) {
  		info = "late type ";
  		callback = pm_late_early_op(dev->type->pm, state);
  	} else if (dev->class && dev->class->pm) {
  		info = "late class ";
  		callback = pm_late_early_op(dev->class->pm, state);
  	} else if (dev->bus && dev->bus->pm) {
  		info = "late bus ";
  		callback = pm_late_early_op(dev->bus->pm, state);
  	}
  
  	if (!callback && dev->driver && dev->driver->pm) {
  		info = "late driver ";
  		callback = pm_late_early_op(dev->driver->pm, state);
  	}
  
  	error = dpm_run_callback(callback, dev, state, info);
  	if (!error)
  		dev->power.is_late_suspended = true;
  	else
  		async_error = error;
  
  Complete:
  	TRACE_SUSPEND(error);
  	complete_all(&dev->power.completion);
  	return error;
  }
  
  static void async_suspend_late(void *data, async_cookie_t cookie)
  {
  	struct device *dev = (struct device *)data;
  	int error;
  
  	error = __device_suspend_late(dev, pm_transition, true);
  	if (error) {
  		dpm_save_failed_dev(dev_name(dev));
  		pm_dev_err(dev, pm_transition, " async", error);
  	}
  	put_device(dev);
  }
  
  static int device_suspend_late(struct device *dev)
  {
  	reinit_completion(&dev->power.completion);
  
  	if (is_async(dev)) {
  		get_device(dev);
  		async_schedule(async_suspend_late, dev);
  		return 0;
  	}
  
  	return __device_suspend_late(dev, pm_transition, false);
  }
  
  /**
   * dpm_suspend_late - Execute "late suspend" callbacks for all devices.
   * @state: PM transition of the system being carried out.
   */
  int dpm_suspend_late(pm_message_t state)
  {
  	ktime_t starttime = ktime_get();
  	int error = 0;
  
  	trace_suspend_resume(TPS("dpm_suspend_late"), state.event, true);
  	mutex_lock(&dpm_list_mtx);
  	pm_transition = state;
  	async_error = 0;
  
  	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_late(dev);
  
  		mutex_lock(&dpm_list_mtx);
  		if (!list_empty(&dev->power.entry))
  			list_move(&dev->power.entry, &dpm_late_early_list);
  
  		if (error) {
  			pm_dev_err(dev, state, " late", error);
  			dpm_save_failed_dev(dev_name(dev));
  			put_device(dev);
  			break;
  		}
  		put_device(dev);
  
  		if (async_error)
  			break;
  	}
  	mutex_unlock(&dpm_list_mtx);
  	async_synchronize_full();
  	if (!error)
  		error = async_error;
  	if (error) {
  		suspend_stats.failed_suspend_late++;
  		dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
  		dpm_resume_early(resume_event(state));
  	}
  	dpm_show_time(starttime, state, error, "late");
  	trace_suspend_resume(TPS("dpm_suspend_late"), state.event, false);
  	return error;
  }
  
  /**
   * dpm_suspend_end - Execute "late" and "noirq" device suspend callbacks.
   * @state: PM transition of the system being carried out.
   */
  int dpm_suspend_end(pm_message_t state)
  {
  	int error = dpm_suspend_late(state);
  	if (error)
  		return error;
  
  	error = dpm_suspend_noirq(state);
  	if (error) {
  		dpm_resume_early(resume_event(state));
  		return error;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(dpm_suspend_end);
  
  /**
   * 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.
   * @info: string description of caller.
   */
  static int legacy_suspend(struct device *dev, pm_message_t state,
  			  int (*cb)(struct device *dev, pm_message_t state),
  			  const char *info)
  {
  	int error;
  	ktime_t calltime;
  
  	calltime = initcall_debug_start(dev);
  
  	trace_device_pm_callback_start(dev, info, state.event);
  	error = cb(dev, state);
  	trace_device_pm_callback_end(dev, error);
  	suspend_report_result(cb, error);
  
  	initcall_debug_report(dev, calltime, error, state, info);
  
  	return error;
  }
  
  static void dpm_clear_suppliers_direct_complete(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) {
  		spin_lock_irq(&link->supplier->power.lock);
  		link->supplier->power.direct_complete = false;
  		spin_unlock_irq(&link->supplier->power.lock);
  	}
  
  	device_links_read_unlock(idx);
  }
  
  /**
   * 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)
  {
  	pm_callback_t callback = NULL;
  	const char *info = NULL;
  	int error = 0;
  	char suspend_abort[MAX_SUSPEND_ABORT_LEN];
  	DECLARE_DPM_WATCHDOG_ON_STACK(wd);
  
  	TRACE_DEVICE(dev);
  	TRACE_SUSPEND(0);
  
  	dpm_wait_for_subordinate(dev, async);
  
  	if (async_error)
  		goto Complete;
  
  	/*
  	 * If a device configured to wake up the system from sleep states
  	 * has been suspended at run time and there's a resume request pending
  	 * for it, this is equivalent to the device signaling wakeup, so the
  	 * system suspend operation should be aborted.
  	 */
  	if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
  		pm_wakeup_event(dev, 0);
  
  	if (pm_wakeup_pending()) {
  		pm_get_active_wakeup_sources(suspend_abort,
  			MAX_SUSPEND_ABORT_LEN);
  		log_suspend_abort_reason(suspend_abort);
  		async_error = -EBUSY;
  		goto Complete;
  	}
  
  	if (dev->power.syscore)
  		goto Complete;
  
  	if (dev->power.direct_complete) {
  		if (pm_runtime_status_suspended(dev)) {
  			pm_runtime_disable(dev);
  			if (pm_runtime_status_suspended(dev))
  				goto Complete;
  
  			pm_runtime_enable(dev);
  		}
  		dev->power.direct_complete = false;
  	}
  
  	dpm_watchdog_set(&wd, dev);
  	device_lock(dev);
  
  	if (dev->pm_domain) {
  		info = "power domain ";
  		callback = pm_op(&dev->pm_domain->ops, state);
  		goto Run;
  	}
  
  	if (dev->type && dev->type->pm) {
  		info = "type ";
  		callback = pm_op(dev->type->pm, state);
  		goto Run;
  	}
  
  	if (dev->class) {
  		if (dev->class->pm) {
  			info = "class ";
  			callback = pm_op(dev->class->pm, state);
  			goto Run;
  		} else if (dev->class->suspend) {
  			pm_dev_dbg(dev, state, "legacy class ");
  			error = legacy_suspend(dev, state, dev->class->suspend,
  						"legacy class ");
  			goto End;
  		}
  	}
  
  	if (dev->bus) {
  		if (dev->bus->pm) {
  			info = "bus ";
  			callback = pm_op(dev->bus->pm, state);
  		} else if (dev->bus->suspend) {
  			pm_dev_dbg(dev, state, "legacy bus ");
  			error = legacy_suspend(dev, state, dev->bus->suspend,
  						"legacy bus ");
  			goto End;
  		}
  	}
  
   Run:
  	if (!callback && dev->driver && dev->driver->pm) {
  		info = "driver ";
  		callback = pm_op(dev->driver->pm, state);
  	}
  
  	error = dpm_run_callback(callback, dev, state, info);
  
   End:
  	if (!error) {
  		struct device *parent = dev->parent;
  
  		dev->power.is_suspended = true;
  		if (parent) {
  			spin_lock_irq(&parent->power.lock);
  
  			dev->parent->power.direct_complete = false;
  			if (dev->power.wakeup_path
  			    && !dev->parent->power.ignore_children)
  				dev->parent->power.wakeup_path = true;
  
  			spin_unlock_irq(&parent->power.lock);
  		}
  		dpm_clear_suppliers_direct_complete(dev);
  	}
  
  	device_unlock(dev);
  	dpm_watchdog_clear(&wd);
  
   Complete:
  	if (error)
  		async_error = error;
  
  	complete_all(&dev->power.completion);
  	TRACE_SUSPEND(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) {
  		dpm_save_failed_dev(dev_name(dev));
  		pm_dev_err(dev, pm_transition, " async", error);
  	}
  
  	put_device(dev);
  }
  
  static int device_suspend(struct device *dev)
  {
  	reinit_completion(&dev->power.completion);
  
  	if (is_async(dev)) {
  		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;
  
  	trace_suspend_resume(TPS("dpm_suspend"), state.event, true);
  	might_sleep();
  
  	cpufreq_suspend();
  
  	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);
  			dpm_save_failed_dev(dev_name(dev));
  			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) {
  		suspend_stats.failed_suspend++;
  		dpm_save_failed_step(SUSPEND_SUSPEND);
  	}
  	dpm_show_time(starttime, state, error, NULL);
  	trace_suspend_resume(TPS("dpm_suspend"), state.event, false);
  	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 (*callback)(struct device *) = NULL;
  	int ret = 0;
  
  	if (dev->power.syscore)
  		return 0;
  
  	/*
  	 * If a device's parent goes into runtime suspend at the wrong time,
  	 * it won't be possible to resume the device.  To prevent this we
  	 * block runtime suspend here, during the prepare phase, and allow
  	 * it again during the complete phase.
  	 */
  	pm_runtime_get_noresume(dev);
  
  	device_lock(dev);
  
  	dev->power.wakeup_path = device_may_wakeup(dev);
  
  	if (dev->power.no_pm_callbacks) {
  		ret = 1;	/* Let device go direct_complete */
  		goto unlock;
  	}
  
  	if (dev->pm_domain)
  		callback = dev->pm_domain->ops.prepare;
  	else if (dev->type && dev->type->pm)
  		callback = dev->type->pm->prepare;
  	else if (dev->class && dev->class->pm)
  		callback = dev->class->pm->prepare;
  	else if (dev->bus && dev->bus->pm)
  		callback = dev->bus->pm->prepare;
  
  	if (!callback && dev->driver && dev->driver->pm)
  		callback = dev->driver->pm->prepare;
  
  	if (callback)
  		ret = callback(dev);
  
  unlock:
  	device_unlock(dev);
  
  	if (ret < 0) {
  		suspend_report_result(callback, ret);
  		pm_runtime_put(dev);
  		return ret;
  	}
  	/*
  	 * A positive return value from ->prepare() means "this device appears
  	 * to be runtime-suspended and its state is fine, so if it really is
  	 * runtime-suspended, you can leave it in that state provided that you
  	 * will do the same thing with all of its descendants".  This only
  	 * applies to suspend transitions, however.
  	 */
  	spin_lock_irq(&dev->power.lock);
  	dev->power.direct_complete = ret > 0 && state.event == PM_EVENT_SUSPEND;
  	spin_unlock_irq(&dev->power.lock);
  	return 0;
  }
  
  /**
   * 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;
  
  	trace_suspend_resume(TPS("dpm_prepare"), state.event, true);
  	might_sleep();
  
  	/*
  	 * Give a chance for the known devices to complete their probes, before
  	 * disable probing of devices. This sync point is important at least
  	 * at boot time + hibernation restore.
  	 */
  	wait_for_device_probe();
  	/*
  	 * It is unsafe if probing of devices will happen during suspend or
  	 * hibernation and system behavior will be unpredictable in this case.
  	 * So, let's prohibit device's probing here and defer their probes
  	 * instead. The normal behavior will be restored in dpm_complete().
  	 */
  	device_block_probing();
  
  	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);
  
  		trace_device_pm_callback_start(dev, "", state.event);
  		error = device_prepare(dev, state);
  		trace_device_pm_callback_end(dev, error);
  
  		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);
  	trace_suspend_resume(TPS("dpm_prepare"), state.event, false);
  	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) {
  		suspend_stats.failed_prepare++;
  		dpm_save_failed_step(SUSPEND_PREPARE);
  	} else
  		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);
  
  /**
   * dpm_for_each_dev - device iterator.
   * @data: data for the callback.
   * @fn: function to be called for each device.
   *
   * Iterate over devices in dpm_list, and call @fn for each device,
   * passing it @data.
   */
  void dpm_for_each_dev(void *data, void (*fn)(struct device *, void *))
  {
  	struct device *dev;
  
  	if (!fn)
  		return;
  
  	device_pm_lock();
  	list_for_each_entry(dev, &dpm_list, power.entry)
  		fn(dev, data);
  	device_pm_unlock();
  }
  EXPORT_SYMBOL_GPL(dpm_for_each_dev);
  
  static bool pm_ops_is_empty(const struct dev_pm_ops *ops)
  {
  	if (!ops)
  		return true;
  
  	return !ops->prepare &&
  	       !ops->suspend &&
  	       !ops->suspend_late &&
  	       !ops->suspend_noirq &&
  	       !ops->resume_noirq &&
  	       !ops->resume_early &&
  	       !ops->resume &&
  	       !ops->complete;
  }
  
  void device_pm_check_callbacks(struct device *dev)
  {
  	spin_lock_irq(&dev->power.lock);
  	dev->power.no_pm_callbacks =
  		(!dev->bus || (pm_ops_is_empty(dev->bus->pm) &&
  		 !dev->bus->suspend && !dev->bus->resume)) &&
  		(!dev->class || (pm_ops_is_empty(dev->class->pm) &&
  		 !dev->class->suspend && !dev->class->resume)) &&
  		(!dev->type || pm_ops_is_empty(dev->type->pm)) &&
  		(!dev->pm_domain || pm_ops_is_empty(&dev->pm_domain->ops)) &&
  		(!dev->driver || (pm_ops_is_empty(dev->driver->pm) &&
  		 !dev->driver->suspend && !dev->driver->resume));
  	spin_unlock_irq(&dev->power.lock);
  }
  