OSCL-LXR linux-6.0.1/​drivers/​base/​power/​wakeup.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * drivers/base/power/wakeup.c - System wakeup events framework
  *
  * Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
  */
 #define pr_fmt(fmt) "PM: " fmt
 
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/sched/signal.h>
 #include <linux/capability.h>
 #include <linux/export.h>
 #include <linux/suspend.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
 #include <linux/pm_wakeirq.h>
 #include <trace/events/power.h>
 
 #include "power.h"
 
 #ifndef CONFIG_SUSPEND
 suspend_state_t pm_suspend_target_state;
 #define pm_suspend_target_state (PM_SUSPEND_ON)
 #endif
 
 #define list_for_each_entry_rcu_locked(pos, head, member) \
     list_for_each_entry_rcu(pos, head, member, \
         srcu_read_lock_held(&wakeup_srcu))
 /*
  * If set, the suspend/hibernate code will abort transitions to a sleep state
  * if wakeup events are registered during or immediately before the transition.
  */
 bool events_check_enabled __read_mostly;
 
 /* First wakeup IRQ seen by the kernel in the last cycle. */
 static unsigned int wakeup_irq[2] __read_mostly;
 static DEFINE_RAW_SPINLOCK(wakeup_irq_lock);
 
 /* If greater than 0 and the system is suspending, terminate the suspend. */
 static atomic_t pm_abort_suspend __read_mostly;
 
 /*
  * Combined counters of registered wakeup events and wakeup events in progress.
  * They need to be modified together atomically, so it's better to use one
  * atomic variable to hold them both.
  */
 static atomic_t combined_event_count = ATOMIC_INIT(0);
 
 #define IN_PROGRESS_BITS    (sizeof(int) * 4)
 #define MAX_IN_PROGRESS     ((1 << IN_PROGRESS_BITS) - 1)
 
 static void split_counters(unsigned int *cnt, unsigned int *inpr)
 {
     unsigned int comb = atomic_read(&combined_event_count);
 
     *cnt = (comb >> IN_PROGRESS_BITS);
     *inpr = comb & MAX_IN_PROGRESS;
 }
 
 /* A preserved old value of the events counter. */
 static unsigned int saved_count;
 
 static DEFINE_RAW_SPINLOCK(events_lock);
 
 static void pm_wakeup_timer_fn(struct timer_list *t);
 
 static LIST_HEAD(wakeup_sources);
 
 static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
 
 DEFINE_STATIC_SRCU(wakeup_srcu);
 
 static struct wakeup_source deleted_ws = {
     .name = "deleted",
     .lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
 };
 
 static DEFINE_IDA(wakeup_ida);
 
 /**
  * wakeup_source_create - Create a struct wakeup_source object.
  * @name: Name of the new wakeup source.
  */
 struct wakeup_source *wakeup_source_create(const char *name)
 {
     struct wakeup_source *ws;
     const char *ws_name;
     int id;
 
     ws = kzalloc(sizeof(*ws), GFP_KERNEL);
     if (!ws)
         goto err_ws;
 
     ws_name = kstrdup_const(name, GFP_KERNEL);
     if (!ws_name)
         goto err_name;
     ws->name = ws_name;
 
     id = ida_alloc(&wakeup_ida, GFP_KERNEL);
     if (id < 0)
         goto err_id;
     ws->id = id;
 
     return ws;
 
 err_id:
     kfree_const(ws->name);
 err_name:
     kfree(ws);
 err_ws:
     return NULL;
 }
 EXPORT_SYMBOL_GPL(wakeup_source_create);
 
 /*
  * Record wakeup_source statistics being deleted into a dummy wakeup_source.
  */
 static void wakeup_source_record(struct wakeup_source *ws)
 {
     unsigned long flags;
 
     spin_lock_irqsave(&deleted_ws.lock, flags);
 
     if (ws->event_count) {
         deleted_ws.total_time =
             ktime_add(deleted_ws.total_time, ws->total_time);
         deleted_ws.prevent_sleep_time =
             ktime_add(deleted_ws.prevent_sleep_time,
                   ws->prevent_sleep_time);
         deleted_ws.max_time =
             ktime_compare(deleted_ws.max_time, ws->max_time) > 0 ?
                 deleted_ws.max_time : ws->max_time;
         deleted_ws.event_count += ws->event_count;
         deleted_ws.active_count += ws->active_count;
         deleted_ws.relax_count += ws->relax_count;
         deleted_ws.expire_count += ws->expire_count;
         deleted_ws.wakeup_count += ws->wakeup_count;
     }
 
     spin_unlock_irqrestore(&deleted_ws.lock, flags);
 }
 
 static void wakeup_source_free(struct wakeup_source *ws)
 {
     ida_free(&wakeup_ida, ws->id);
     kfree_const(ws->name);
     kfree(ws);
 }
 
 /**
  * wakeup_source_destroy - Destroy a struct wakeup_source object.
  * @ws: Wakeup source to destroy.
  *
  * Use only for wakeup source objects created with wakeup_source_create().
  */
 void wakeup_source_destroy(struct wakeup_source *ws)
 {
     if (!ws)
         return;
 
     __pm_relax(ws);
     wakeup_source_record(ws);
     wakeup_source_free(ws);
 }
 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
 
 /**
  * wakeup_source_add - Add given object to the list of wakeup sources.
  * @ws: Wakeup source object to add to the list.
  */
 void wakeup_source_add(struct wakeup_source *ws)
 {
     unsigned long flags;
 
     if (WARN_ON(!ws))
         return;
 
     spin_lock_init(&ws->lock);
     timer_setup(&ws->timer, pm_wakeup_timer_fn, 0);
     ws->active = false;
 
     raw_spin_lock_irqsave(&events_lock, flags);
     list_add_rcu(&ws->entry, &wakeup_sources);
     raw_spin_unlock_irqrestore(&events_lock, flags);
 }
 EXPORT_SYMBOL_GPL(wakeup_source_add);
 
 /**
  * wakeup_source_remove - Remove given object from the wakeup sources list.
  * @ws: Wakeup source object to remove from the list.
  */
 void wakeup_source_remove(struct wakeup_source *ws)
 {
     unsigned long flags;
 
     if (WARN_ON(!ws))
         return;
 
     raw_spin_lock_irqsave(&events_lock, flags);
     list_del_rcu(&ws->entry);
     raw_spin_unlock_irqrestore(&events_lock, flags);
     synchronize_srcu(&wakeup_srcu);
 
     del_timer_sync(&ws->timer);
     /*
      * Clear timer.function to make wakeup_source_not_registered() treat
      * this wakeup source as not registered.
      */
     ws->timer.function = NULL;
 }
 EXPORT_SYMBOL_GPL(wakeup_source_remove);
 
 /**
  * wakeup_source_register - Create wakeup source and add it to the list.
  * @dev: Device this wakeup source is associated with (or NULL if virtual).
  * @name: Name of the wakeup source to register.
  */
 struct wakeup_source *wakeup_source_register(struct device *dev,
                          const char *name)
 {
     struct wakeup_source *ws;
     int ret;
 
     ws = wakeup_source_create(name);
     if (ws) {
         if (!dev || device_is_registered(dev)) {
             ret = wakeup_source_sysfs_add(dev, ws);
             if (ret) {
                 wakeup_source_free(ws);
                 return NULL;
             }
         }
         wakeup_source_add(ws);
     }
     return ws;
 }
 EXPORT_SYMBOL_GPL(wakeup_source_register);
 
 /**
  * wakeup_source_unregister - Remove wakeup source from the list and remove it.
  * @ws: Wakeup source object to unregister.
  */
 void wakeup_source_unregister(struct wakeup_source *ws)
 {
     if (ws) {
         wakeup_source_remove(ws);
         if (ws->dev)
             wakeup_source_sysfs_remove(ws);
 
         wakeup_source_destroy(ws);
     }
 }
 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
 
 /**
  * wakeup_sources_read_lock - Lock wakeup source list for read.
  *
  * Returns an index of srcu lock for struct wakeup_srcu.
  * This index must be passed to the matching wakeup_sources_read_unlock().
  */
 int wakeup_sources_read_lock(void)
 {
     return srcu_read_lock(&wakeup_srcu);
 }
 EXPORT_SYMBOL_GPL(wakeup_sources_read_lock);
 
 /**
  * wakeup_sources_read_unlock - Unlock wakeup source list.
  * @idx: return value from corresponding wakeup_sources_read_lock()
  */
 void wakeup_sources_read_unlock(int idx)
 {
     srcu_read_unlock(&wakeup_srcu, idx);
 }
 EXPORT_SYMBOL_GPL(wakeup_sources_read_unlock);
 
 /**
  * wakeup_sources_walk_start - Begin a walk on wakeup source list
  *
  * Returns first object of the list of wakeup sources.
  *
  * Note that to be safe, wakeup sources list needs to be locked by calling
  * wakeup_source_read_lock() for this.
  */
 struct wakeup_source *wakeup_sources_walk_start(void)
 {
     struct list_head *ws_head = &wakeup_sources;
 
     return list_entry_rcu(ws_head->next, struct wakeup_source, entry);
 }
 EXPORT_SYMBOL_GPL(wakeup_sources_walk_start);
 
 /**
  * wakeup_sources_walk_next - Get next wakeup source from the list
  * @ws: Previous wakeup source object
  *
  * Note that to be safe, wakeup sources list needs to be locked by calling
  * wakeup_source_read_lock() for this.
  */
 struct wakeup_source *wakeup_sources_walk_next(struct wakeup_source *ws)
 {
     struct list_head *ws_head = &wakeup_sources;
 
     return list_next_or_null_rcu(ws_head, &ws->entry,
                 struct wakeup_source, entry);
 }
 EXPORT_SYMBOL_GPL(wakeup_sources_walk_next);
 
 /**
  * device_wakeup_attach - Attach a wakeup source object to a device object.
  * @dev: Device to handle.
  * @ws: Wakeup source object to attach to @dev.
  *
  * This causes @dev to be treated as a wakeup device.
  */
 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
 {
     spin_lock_irq(&dev->power.lock);
     if (dev->power.wakeup) {
         spin_unlock_irq(&dev->power.lock);
         return -EEXIST;
     }
     dev->power.wakeup = ws;
     if (dev->power.wakeirq)
         device_wakeup_attach_irq(dev, dev->power.wakeirq);
     spin_unlock_irq(&dev->power.lock);
     return 0;
 }
 
 /**
  * device_wakeup_enable - Enable given device to be a wakeup source.
  * @dev: Device to handle.
  *
  * Create a wakeup source object, register it and attach it to @dev.
  */
 int device_wakeup_enable(struct device *dev)
 {
     struct wakeup_source *ws;
     int ret;
 
     if (!dev || !dev->power.can_wakeup)
         return -EINVAL;
 
     if (pm_suspend_target_state != PM_SUSPEND_ON)
         dev_dbg(dev, "Suspicious %s() during system transition!\n", __func__);
 
     ws = wakeup_source_register(dev, dev_name(dev));
     if (!ws)
         return -ENOMEM;
 
     ret = device_wakeup_attach(dev, ws);
     if (ret)
         wakeup_source_unregister(ws);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(device_wakeup_enable);
 
 /**
  * device_wakeup_attach_irq - Attach a wakeirq to a wakeup source
  * @dev: Device to handle
  * @wakeirq: Device specific wakeirq entry
  *
  * Attach a device wakeirq to the wakeup source so the device
  * wake IRQ can be configured automatically for suspend and
  * resume.
  *
  * Call under the device's power.lock lock.
  */
 void device_wakeup_attach_irq(struct device *dev,
                  struct wake_irq *wakeirq)
 {
     struct wakeup_source *ws;
 
     ws = dev->power.wakeup;
     if (!ws)
         return;
 
     if (ws->wakeirq)
         dev_err(dev, "Leftover wakeup IRQ found, overriding\n");
 
     ws->wakeirq = wakeirq;
 }
 
 /**
  * device_wakeup_detach_irq - Detach a wakeirq from a wakeup source
  * @dev: Device to handle
  *
  * Removes a device wakeirq from the wakeup source.
  *
  * Call under the device's power.lock lock.
  */
 void device_wakeup_detach_irq(struct device *dev)
 {
     struct wakeup_source *ws;
 
     ws = dev->power.wakeup;
     if (ws)
         ws->wakeirq = NULL;
 }
 
 /**
  * device_wakeup_arm_wake_irqs -
  *
  * Iterates over the list of device wakeirqs to arm them.
  */
 void device_wakeup_arm_wake_irqs(void)
 {
     struct wakeup_source *ws;
     int srcuidx;
 
     srcuidx = srcu_read_lock(&wakeup_srcu);
     list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry)
         dev_pm_arm_wake_irq(ws->wakeirq);
     srcu_read_unlock(&wakeup_srcu, srcuidx);
 }
 
 /**
  * device_wakeup_disarm_wake_irqs -
  *
  * Iterates over the list of device wakeirqs to disarm them.
  */
 void device_wakeup_disarm_wake_irqs(void)
 {
     struct wakeup_source *ws;
     int srcuidx;
 
     srcuidx = srcu_read_lock(&wakeup_srcu);
     list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry)
         dev_pm_disarm_wake_irq(ws->wakeirq);
     srcu_read_unlock(&wakeup_srcu, srcuidx);
 }
 
 /**
  * device_wakeup_detach - Detach a device's wakeup source object from it.
  * @dev: Device to detach the wakeup source object from.
  *
  * After it returns, @dev will not be treated as a wakeup device any more.
  */
 static struct wakeup_source *device_wakeup_detach(struct device *dev)
 {
     struct wakeup_source *ws;
 
     spin_lock_irq(&dev->power.lock);
     ws = dev->power.wakeup;
     dev->power.wakeup = NULL;
     spin_unlock_irq(&dev->power.lock);
     return ws;
 }
 
 /**
  * device_wakeup_disable - Do not regard a device as a wakeup source any more.
  * @dev: Device to handle.
  *
  * Detach the @dev's wakeup source object from it, unregister this wakeup source
  * object and destroy it.
  */
 int device_wakeup_disable(struct device *dev)
 {
     struct wakeup_source *ws;
 
     if (!dev || !dev->power.can_wakeup)
         return -EINVAL;
 
     ws = device_wakeup_detach(dev);
     wakeup_source_unregister(ws);
     return 0;
 }
 EXPORT_SYMBOL_GPL(device_wakeup_disable);
 
 /**
  * device_set_wakeup_capable - Set/reset device wakeup capability flag.
  * @dev: Device to handle.
  * @capable: Whether or not @dev is capable of waking up the system from sleep.
  *
  * If @capable is set, set the @dev's power.can_wakeup flag and add its
  * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
  * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
  *
  * This function may sleep and it can't be called from any context where
  * sleeping is not allowed.
  */
 void device_set_wakeup_capable(struct device *dev, bool capable)
 {
     if (!!dev->power.can_wakeup == !!capable)
         return;
 
     dev->power.can_wakeup = capable;
     if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
         if (capable) {
             int ret = wakeup_sysfs_add(dev);
 
             if (ret)
                 dev_info(dev, "Wakeup sysfs attributes not added\n");
         } else {
             wakeup_sysfs_remove(dev);
         }
     }
 }
 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
 
 /**
  * device_set_wakeup_enable - Enable or disable a device to wake up the system.
  * @dev: Device to handle.
  * @enable: enable/disable flag
  */
 int device_set_wakeup_enable(struct device *dev, bool enable)
 {
     return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
 }
 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 
 /**
  * wakeup_source_not_registered - validate the given wakeup source.
  * @ws: Wakeup source to be validated.
  */
 static bool wakeup_source_not_registered(struct wakeup_source *ws)
 {
     /*
      * Use timer struct to check if the given source is initialized
      * by wakeup_source_add.
      */
     return ws->timer.function != pm_wakeup_timer_fn;
 }
 
 /*
  * The functions below use the observation that each wakeup event starts a
  * period in which the system should not be suspended.  The moment this period
  * will end depends on how the wakeup event is going to be processed after being
  * detected and all of the possible cases can be divided into two distinct
  * groups.
  *
  * First, a wakeup event may be detected by the same functional unit that will
  * carry out the entire processing of it and possibly will pass it to user space
  * for further processing.  In that case the functional unit that has detected
  * the event may later "close" the "no suspend" period associated with it
  * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
  * pm_relax(), balanced with each other, is supposed to be used in such
  * situations.
  *
  * Second, a wakeup event may be detected by one functional unit and processed
  * by another one.  In that case the unit that has detected it cannot really
  * "close" the "no suspend" period associated with it, unless it knows in
  * advance what's going to happen to the event during processing.  This
  * knowledge, however, may not be available to it, so it can simply specify time
  * to wait before the system can be suspended and pass it as the second
  * argument of pm_wakeup_event().
  *
  * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
  * "no suspend" period will be ended either by the pm_relax(), or by the timer
  * function executed when the timer expires, whichever comes first.
  */
 
 /**
  * wakeup_source_activate - Mark given wakeup source as active.
  * @ws: Wakeup source to handle.
  *
  * Update the @ws' statistics and, if @ws has just been activated, notify the PM
  * core of the event by incrementing the counter of the wakeup events being
  * processed.
  */
 static void wakeup_source_activate(struct wakeup_source *ws)
 {
     unsigned int cec;
 
     if (WARN_ONCE(wakeup_source_not_registered(ws),
             "unregistered wakeup source\n"))
         return;
 
     ws->active = true;
     ws->active_count++;
     ws->last_time = ktime_get();
     if (ws->autosleep_enabled)
         ws->start_prevent_time = ws->last_time;
 
     /* Increment the counter of events in progress. */
     cec = atomic_inc_return(&combined_event_count);
 
     trace_wakeup_source_activate(ws->name, cec);
 }
 
 /**
  * wakeup_source_report_event - Report wakeup event using the given source.
  * @ws: Wakeup source to report the event for.
  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
  */
 static void wakeup_source_report_event(struct wakeup_source *ws, bool hard)
 {
     ws->event_count++;
     /* This is racy, but the counter is approximate anyway. */
     if (events_check_enabled)
         ws->wakeup_count++;
 
     if (!ws->active)
         wakeup_source_activate(ws);
 
     if (hard)
         pm_system_wakeup();
 }
 
 /**
  * __pm_stay_awake - Notify the PM core of a wakeup event.
  * @ws: Wakeup source object associated with the source of the event.
  *
  * It is safe to call this function from interrupt context.
  */
 void __pm_stay_awake(struct wakeup_source *ws)
 {
     unsigned long flags;
 
     if (!ws)
         return;
 
     spin_lock_irqsave(&ws->lock, flags);
 
     wakeup_source_report_event(ws, false);
     del_timer(&ws->timer);
     ws->timer_expires = 0;
 
     spin_unlock_irqrestore(&ws->lock, flags);
 }
 EXPORT_SYMBOL_GPL(__pm_stay_awake);
 
 /**
  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
  * @dev: Device the wakeup event is related to.
  *
  * Notify the PM core of a wakeup event (signaled by @dev) by calling
  * __pm_stay_awake for the @dev's wakeup source object.
  *
  * Call this function after detecting of a wakeup event if pm_relax() is going
  * to be called directly after processing the event (and possibly passing it to
  * user space for further processing).
  */
 void pm_stay_awake(struct device *dev)
 {
     unsigned long flags;
 
     if (!dev)
         return;
 
     spin_lock_irqsave(&dev->power.lock, flags);
     __pm_stay_awake(dev->power.wakeup);
     spin_unlock_irqrestore(&dev->power.lock, flags);
 }
 EXPORT_SYMBOL_GPL(pm_stay_awake);
 
 #ifdef CONFIG_PM_AUTOSLEEP
 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
 {
     ktime_t delta = ktime_sub(now, ws->start_prevent_time);
     ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
 }
 #else
 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
                          ktime_t now) {}
 #endif
 
 /**
  * wakeup_source_deactivate - Mark given wakeup source as inactive.
  * @ws: Wakeup source to handle.
  *
  * Update the @ws' statistics and notify the PM core that the wakeup source has
  * become inactive by decrementing the counter of wakeup events being processed
  * and incrementing the counter of registered wakeup events.
  */
 static void wakeup_source_deactivate(struct wakeup_source *ws)
 {
     unsigned int cnt, inpr, cec;
     ktime_t duration;
     ktime_t now;
 
     ws->relax_count++;
     /*
      * __pm_relax() may be called directly or from a timer function.
      * If it is called directly right after the timer function has been
      * started, but before the timer function calls __pm_relax(), it is
      * possible that __pm_stay_awake() will be called in the meantime and
      * will set ws->active.  Then, ws->active may be cleared immediately
      * by the __pm_relax() called from the timer function, but in such a
      * case ws->relax_count will be different from ws->active_count.
      */
     if (ws->relax_count != ws->active_count) {
         ws->relax_count--;
         return;
     }
 
     ws->active = false;
 
     now = ktime_get();
     duration = ktime_sub(now, ws->last_time);
     ws->total_time = ktime_add(ws->total_time, duration);
     if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
         ws->max_time = duration;
 
     ws->last_time = now;
     del_timer(&ws->timer);
     ws->timer_expires = 0;
 
     if (ws->autosleep_enabled)
         update_prevent_sleep_time(ws, now);
 
     /*
      * Increment the counter of registered wakeup events and decrement the
      * counter of wakeup events in progress simultaneously.
      */
     cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
     trace_wakeup_source_deactivate(ws->name, cec);
 
     split_counters(&cnt, &inpr);
     if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
         wake_up(&wakeup_count_wait_queue);
 }
 
 /**
  * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
  * @ws: Wakeup source object associated with the source of the event.
  *
  * Call this function for wakeup events whose processing started with calling
  * __pm_stay_awake().
  *
  * It is safe to call it from interrupt context.
  */
 void __pm_relax(struct wakeup_source *ws)
 {
     unsigned long flags;
 
     if (!ws)
         return;
 
     spin_lock_irqsave(&ws->lock, flags);
     if (ws->active)
         wakeup_source_deactivate(ws);
     spin_unlock_irqrestore(&ws->lock, flags);
 }
 EXPORT_SYMBOL_GPL(__pm_relax);
 
 /**
  * pm_relax - Notify the PM core that processing of a wakeup event has ended.
  * @dev: Device that signaled the event.
  *
  * Execute __pm_relax() for the @dev's wakeup source object.
  */
 void pm_relax(struct device *dev)
 {
     unsigned long flags;
 
     if (!dev)
         return;
 
     spin_lock_irqsave(&dev->power.lock, flags);
     __pm_relax(dev->power.wakeup);
     spin_unlock_irqrestore(&dev->power.lock, flags);
 }
 EXPORT_SYMBOL_GPL(pm_relax);
 
 /**
  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
  * @t: timer list
  *
  * Call wakeup_source_deactivate() for the wakeup source whose address is stored
  * in @data if it is currently active and its timer has not been canceled and
  * the expiration time of the timer is not in future.
  */
 static void pm_wakeup_timer_fn(struct timer_list *t)
 {
     struct wakeup_source *ws = from_timer(ws, t, timer);
     unsigned long flags;
 
     spin_lock_irqsave(&ws->lock, flags);
 
     if (ws->active && ws->timer_expires
         && time_after_eq(jiffies, ws->timer_expires)) {
         wakeup_source_deactivate(ws);
         ws->expire_count++;
     }
 
     spin_unlock_irqrestore(&ws->lock, flags);
 }
 
 /**
  * pm_wakeup_ws_event - Notify the PM core of a wakeup event.
  * @ws: Wakeup source object associated with the event source.
  * @msec: Anticipated event processing time (in milliseconds).
  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
  *
  * Notify the PM core of a wakeup event whose source is @ws that will take
  * approximately @msec milliseconds to be processed by the kernel.  If @ws is
  * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
  * execute pm_wakeup_timer_fn() in future.
  *
  * It is safe to call this function from interrupt context.
  */
 void pm_wakeup_ws_event(struct wakeup_source *ws, unsigned int msec, bool hard)
 {
     unsigned long flags;
     unsigned long expires;
 
     if (!ws)
         return;
 
     spin_lock_irqsave(&ws->lock, flags);
 
     wakeup_source_report_event(ws, hard);
 
     if (!msec) {
         wakeup_source_deactivate(ws);
         goto unlock;
     }
 
     expires = jiffies + msecs_to_jiffies(msec);
     if (!expires)
         expires = 1;
 
     if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
         mod_timer(&ws->timer, expires);
         ws->timer_expires = expires;
     }
 
  unlock:
     spin_unlock_irqrestore(&ws->lock, flags);
 }
 EXPORT_SYMBOL_GPL(pm_wakeup_ws_event);
 
 /**
  * pm_wakeup_dev_event - Notify the PM core of a wakeup event.
  * @dev: Device the wakeup event is related to.
  * @msec: Anticipated event processing time (in milliseconds).
  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
  *
  * Call pm_wakeup_ws_event() for the @dev's wakeup source object.
  */
 void pm_wakeup_dev_event(struct device *dev, unsigned int msec, bool hard)
 {
     unsigned long flags;
 
     if (!dev)
         return;
 
     spin_lock_irqsave(&dev->power.lock, flags);
     pm_wakeup_ws_event(dev->power.wakeup, msec, hard);
     spin_unlock_irqrestore(&dev->power.lock, flags);
 }
 EXPORT_SYMBOL_GPL(pm_wakeup_dev_event);
 
 void pm_print_active_wakeup_sources(void)
 {
     struct wakeup_source *ws;
     int srcuidx, active = 0;
     struct wakeup_source *last_activity_ws = NULL;
 
     srcuidx = srcu_read_lock(&wakeup_srcu);
     list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
         if (ws->active) {
             pm_pr_dbg("active wakeup source: %s\n", ws->name);
             active = 1;
         } else if (!active &&
                (!last_activity_ws ||
                 ktime_to_ns(ws->last_time) >
                 ktime_to_ns(last_activity_ws->last_time))) {
             last_activity_ws = ws;
         }
     }
 
     if (!active && last_activity_ws)
         pm_pr_dbg("last active wakeup source: %s\n",
             last_activity_ws->name);
     srcu_read_unlock(&wakeup_srcu, srcuidx);
 }
 EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);
 
 /**
  * pm_wakeup_pending - Check if power transition in progress should be aborted.
  *
  * Compare the current number of registered wakeup events with its preserved
  * value from the past and return true if new wakeup events have been registered
  * since the old value was stored.  Also return true if the current number of
  * wakeup events being processed is different from zero.
  */
 bool pm_wakeup_pending(void)
 {
     unsigned long flags;
     bool ret = false;
 
     raw_spin_lock_irqsave(&events_lock, flags);
     if (events_check_enabled) {
         unsigned int cnt, inpr;
 
         split_counters(&cnt, &inpr);
         ret = (cnt != saved_count || inpr > 0);
         events_check_enabled = !ret;
     }
     raw_spin_unlock_irqrestore(&events_lock, flags);
 
     if (ret) {
         pm_pr_dbg("Wakeup pending, aborting suspend\n");
         pm_print_active_wakeup_sources();
     }
 
     return ret || atomic_read(&pm_abort_suspend) > 0;
 }
 EXPORT_SYMBOL_GPL(pm_wakeup_pending);
 
 void pm_system_wakeup(void)
 {
     atomic_inc(&pm_abort_suspend);
     s2idle_wake();
 }
 EXPORT_SYMBOL_GPL(pm_system_wakeup);
 
 void pm_system_cancel_wakeup(void)
 {
     atomic_dec_if_positive(&pm_abort_suspend);
 }
 
 void pm_wakeup_clear(unsigned int irq_number)
 {
     raw_spin_lock_irq(&wakeup_irq_lock);
 
     if (irq_number && wakeup_irq[0] == irq_number)
         wakeup_irq[0] = wakeup_irq[1];
     else
         wakeup_irq[0] = 0;
 
     wakeup_irq[1] = 0;
 
     raw_spin_unlock_irq(&wakeup_irq_lock);
 
     if (!irq_number)
         atomic_set(&pm_abort_suspend, 0);
 }
 
 void pm_system_irq_wakeup(unsigned int irq_number)
 {
     unsigned long flags;
 
     raw_spin_lock_irqsave(&wakeup_irq_lock, flags);
 
     if (wakeup_irq[0] == 0)
         wakeup_irq[0] = irq_number;
     else if (wakeup_irq[1] == 0)
         wakeup_irq[1] = irq_number;
     else
         irq_number = 0;
 
     raw_spin_unlock_irqrestore(&wakeup_irq_lock, flags);
 
     if (irq_number)
         pm_system_wakeup();
 }
 
 unsigned int pm_wakeup_irq(void)
 {
     return wakeup_irq[0];
 }
 
 /**
  * pm_get_wakeup_count - Read the number of registered wakeup events.
  * @count: Address to store the value at.
  * @block: Whether or not to block.
  *
  * Store the number of registered wakeup events at the address in @count.  If
  * @block is set, block until the current number of wakeup events being
  * processed is zero.
  *
  * Return 'false' if the current number of wakeup events being processed is
  * nonzero.  Otherwise return 'true'.
  */
 bool pm_get_wakeup_count(unsigned int *count, bool block)
 {
     unsigned int cnt, inpr;
 
     if (block) {
         DEFINE_WAIT(wait);
 
         for (;;) {
             prepare_to_wait(&wakeup_count_wait_queue, &wait,
                     TASK_INTERRUPTIBLE);
             split_counters(&cnt, &inpr);
             if (inpr == 0 || signal_pending(current))
                 break;
             pm_print_active_wakeup_sources();
             schedule();
         }
         finish_wait(&wakeup_count_wait_queue, &wait);
     }
 
     split_counters(&cnt, &inpr);
     *count = cnt;
     return !inpr;
 }
 
 /**
  * pm_save_wakeup_count - Save the current number of registered wakeup events.
  * @count: Value to compare with the current number of registered wakeup events.
  *
  * If @count is equal to the current number of registered wakeup events and the
  * current number of wakeup events being processed is zero, store @count as the
  * old number of registered wakeup events for pm_check_wakeup_events(), enable
  * wakeup events detection and return 'true'.  Otherwise disable wakeup events
  * detection and return 'false'.
  */
 bool pm_save_wakeup_count(unsigned int count)
 {
     unsigned int cnt, inpr;
     unsigned long flags;
 
     events_check_enabled = false;
     raw_spin_lock_irqsave(&events_lock, flags);
     split_counters(&cnt, &inpr);
     if (cnt == count && inpr == 0) {
         saved_count = count;
         events_check_enabled = true;
     }
     raw_spin_unlock_irqrestore(&events_lock, flags);
     return events_check_enabled;
 }
 
 #ifdef CONFIG_PM_AUTOSLEEP
 /**
  * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
  * @set: Whether to set or to clear the autosleep_enabled flags.
  */
 void pm_wakep_autosleep_enabled(bool set)
 {
     struct wakeup_source *ws;
     ktime_t now = ktime_get();
     int srcuidx;
 
     srcuidx = srcu_read_lock(&wakeup_srcu);
     list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
         spin_lock_irq(&ws->lock);
         if (ws->autosleep_enabled != set) {
             ws->autosleep_enabled = set;
             if (ws->active) {
                 if (set)
                     ws->start_prevent_time = now;
                 else
                     update_prevent_sleep_time(ws, now);
             }
         }
         spin_unlock_irq(&ws->lock);
     }
     srcu_read_unlock(&wakeup_srcu, srcuidx);
 }
 #endif /* CONFIG_PM_AUTOSLEEP */
 
 /**
  * print_wakeup_source_stats - Print wakeup source statistics information.
  * @m: seq_file to print the statistics into.
  * @ws: Wakeup source object to print the statistics for.
  */
 static int print_wakeup_source_stats(struct seq_file *m,
                      struct wakeup_source *ws)
 {
     unsigned long flags;
     ktime_t total_time;
     ktime_t max_time;
     unsigned long active_count;
     ktime_t active_time;
     ktime_t prevent_sleep_time;
 
     spin_lock_irqsave(&ws->lock, flags);
 
     total_time = ws->total_time;
     max_time = ws->max_time;
     prevent_sleep_time = ws->prevent_sleep_time;
     active_count = ws->active_count;
     if (ws->active) {
         ktime_t now = ktime_get();
 
         active_time = ktime_sub(now, ws->last_time);
         total_time = ktime_add(total_time, active_time);
         if (active_time > max_time)
             max_time = active_time;
 
         if (ws->autosleep_enabled)
             prevent_sleep_time = ktime_add(prevent_sleep_time,
                 ktime_sub(now, ws->start_prevent_time));
     } else {
         active_time = 0;
     }
 
     seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t%lu\t\t%lld\t\t%lld\t\t%lld\t\t%lld\t\t%lld\n",
            ws->name, active_count, ws->event_count,
            ws->wakeup_count, ws->expire_count,
            ktime_to_ms(active_time), ktime_to_ms(total_time),
            ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
            ktime_to_ms(prevent_sleep_time));
 
     spin_unlock_irqrestore(&ws->lock, flags);
 
     return 0;
 }
 
 static void *wakeup_sources_stats_seq_start(struct seq_file *m,
                     loff_t *pos)
 {
     struct wakeup_source *ws;
     loff_t n = *pos;
     int *srcuidx = m->private;
 
     if (n == 0) {
         seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
             "expire_count\tactive_since\ttotal_time\tmax_time\t"
             "last_change\tprevent_suspend_time\n");
     }
 
     *srcuidx = srcu_read_lock(&wakeup_srcu);
     list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
         if (n-- <= 0)
             return ws;
     }
 
     return NULL;
 }
 
 static void *wakeup_sources_stats_seq_next(struct seq_file *m,
                     void *v, loff_t *pos)
 {
     struct wakeup_source *ws = v;
     struct wakeup_source *next_ws = NULL;
 
     ++(*pos);
 
     list_for_each_entry_continue_rcu(ws, &wakeup_sources, entry) {
         next_ws = ws;
         break;
     }
 
     if (!next_ws)
         print_wakeup_source_stats(m, &deleted_ws);
 
     return next_ws;
 }
 
 static void wakeup_sources_stats_seq_stop(struct seq_file *m, void *v)
 {
     int *srcuidx = m->private;
 
     srcu_read_unlock(&wakeup_srcu, *srcuidx);
 }
 
 /**
  * wakeup_sources_stats_seq_show - Print wakeup sources statistics information.
  * @m: seq_file to print the statistics into.
  * @v: wakeup_source of each iteration
  */
 static int wakeup_sources_stats_seq_show(struct seq_file *m, void *v)
 {
     struct wakeup_source *ws = v;
 
     print_wakeup_source_stats(m, ws);
 
     return 0;
 }
 
 static const struct seq_operations wakeup_sources_stats_seq_ops = {
     .start = wakeup_sources_stats_seq_start,
     .next  = wakeup_sources_stats_seq_next,
     .stop  = wakeup_sources_stats_seq_stop,
     .show  = wakeup_sources_stats_seq_show,
 };
 
 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
 {
     return seq_open_private(file, &wakeup_sources_stats_seq_ops, sizeof(int));
 }
 
 static const struct file_operations wakeup_sources_stats_fops = {
     .owner = THIS_MODULE,
     .open = wakeup_sources_stats_open,
     .read = seq_read,
     .llseek = seq_lseek,
     .release = seq_release_private,
 };
 
 static int __init wakeup_sources_debugfs_init(void)
 {
     debugfs_create_file("wakeup_sources", 0444, NULL, NULL,
                 &wakeup_sources_stats_fops);
     return 0;
 }
 
 postcore_initcall(wakeup_sources_debugfs_init);

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