Linux电源管理-wakeup events framework

/**
 * struct wakeup_source - Representation of wakeup sources
 *
 * @total_time: Total time this wakeup source has been active.
 * @max_time: Maximum time this wakeup source has been continuously active.
 * @last_time: Monotonic clock when the wakeup source's was touched last time.
 * @prevent_sleep_time: Total time this source has been preventing autosleep.
 * @event_count: Number of signaled wakeup events.
 * @active_count: Number of times the wakeup source was activated.
 * @relax_count: Number of times the wakeup source was deactivated.
 * @expire_count: Number of times the wakeup source's timeout has expired.
 * @wakeup_count: Number of times the wakeup source might abort suspend.
 * @active: Status of the wakeup source.
 * @has_timeout: The wakeup source has been activated with a timeout.
 */
struct wakeup_source {
	const char 		*name;
	struct list_head	entry;
	spinlock_t		lock;
	struct timer_list	timer;
	unsigned long		timer_expires;
	ktime_t total_time;
	ktime_t max_time;
	ktime_t last_time;
	ktime_t start_prevent_time;
	ktime_t prevent_sleep_time;
	unsigned long		event_count;
	unsigned long		active_count;
	unsigned long		relax_count;
	unsigned long		expire_count;
	unsigned long		wakeup_count;
	bool			active:1;
	bool			autosleep_enabled:1;
};

struct device {
    ...
	struct dev_pm_info	power; 
	struct dev_pm_domain	*pm_domain;
	...
}

struct dev_pm_info {
	pm_message_t		power_state;
	unsigned int		can_wakeup:1;
	unsigned int		async_suspend:1;
	
    ...
#ifdef CONFIG_PM_SLEEP
	struct list_head	entry;
	struct completion	completion;
	struct wakeup_source	*wakeup;
	bool			wakeup_path:1;
	bool			syscore:1;
#else
	unsigned int		should_wakeup:1;
#endif
	...
}

static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
{
	struct wakeup_source *ws;

	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");

	rcu_read_lock();
	list_for_each_entry_rcu(ws, &wakeup_sources, entry)
		print_wakeup_source_stats(m, ws);
	rcu_read_unlock();

	return 0;
}

static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
{
	return single_open(file, wakeup_sources_stats_show, NULL);
}

static const struct file_operations wakeup_sources_stats_fops = {
	.owner = THIS_MODULE,
	.open = wakeup_sources_stats_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int __init wakeup_sources_debugfs_init(void)
{
	wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
			S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
	return 0;
}

root@test:/ # cat /sys/kernel/debug/wakeup_sources                    
name		active_count	event_count	wakeup_count	expire_count	active_since	total_time	max_time	last_change	prevent_suspend_time
event1      	40644		40644		0		0		0		31294		30		537054822		0
event4      	4496		4496		0		0		0		13369		22		20913677		0
event5      	4496		4496		0		0		0		13048		22		20913677		0
event0      	4540		4540		0		0		0		27995		277		258270184		0
eventpoll   	40688		54176		0		0		0		217		5		537054822		0
NETLINK     	2175		2175		0		0		0		16960		59		537058523		0

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);

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);
	del_timer(&ws->timer);
	ws->timer_expires = 0;

	spin_unlock_irqrestore(&ws->lock, flags);
}

static void wakeup_source_report_event(struct wakeup_source *ws)
{
	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 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;

static void wakeup_source_activate(struct wakeup_source *ws)
{
	unsigned int cec;

	/*
	 * active wakeup source should bring the system
	 * out of PM_SUSPEND_FREEZE state
	 */
	freeze_wake();

	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);
}

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);
}

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);
}

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
	 * couter 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);
}

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);
}

int device_init_wakeup(struct device *dev, bool enable)
{
	int ret = 0;

	if (!dev)
		return -EINVAL;

	if (enable) {
		device_set_wakeup_capable(dev, true);
		ret = device_wakeup_enable(dev);
	} else {
		if (dev->power.can_wakeup)
			device_wakeup_disable(dev);

		device_set_wakeup_capable(dev, false);
	}

	return ret;
}

void device_set_wakeup_capable(struct device *dev, bool capable)
{
	if (!!dev->power.can_wakeup == !!capable)
		return;

	if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
		if (capable) {
			if (wakeup_sysfs_add(dev))
				return;
		} else {
			wakeup_sysfs_remove(dev);
		}
	}
	dev->power.can_wakeup = capable;
}

static struct attribute *wakeup_attrs[] = {
#ifdef CONFIG_PM_SLEEP
	&dev_attr_wakeup.attr,
	&dev_attr_wakeup_count.attr,
	&dev_attr_wakeup_active_count.attr,
	&dev_attr_wakeup_abort_count.attr,
	&dev_attr_wakeup_expire_count.attr,
	&dev_attr_wakeup_active.attr,
	&dev_attr_wakeup_total_time_ms.attr,
	&dev_attr_wakeup_max_time_ms.attr,
	&dev_attr_wakeup_last_time_ms.attr,
#ifdef CONFIG_PM_AUTOSLEEP
	&dev_attr_wakeup_prevent_sleep_time_ms.attr,
#endif
#endif
	NULL,
};
static struct attribute_group pm_wakeup_attr_group = {
	.name	= power_group_name,
	.attrs	= wakeup_attrs,
};

int device_wakeup_enable(struct device *dev)
{
	struct wakeup_source *ws;
	int ret;

	if (!dev || !dev->power.can_wakeup)
		return -EINVAL;

	ws = wakeup_source_register(dev_name(dev));
	if (!ws)
		return -ENOMEM;

	ret = device_wakeup_attach(dev, ws);
	if (ret)
		wakeup_source_unregister(ws);

	return ret;
}

struct wakeup_source *wakeup_source_register(const char *name)
{
	struct wakeup_source *ws;

	ws = wakeup_source_create(name);
	if (ws)
		wakeup_source_add(ws);

	return ws;
}

struct wakeup_source *wakeup_source_create(const char *name)
{
	struct wakeup_source *ws;

	ws = kmalloc(sizeof(*ws), GFP_KERNEL);
	if (!ws)
		return NULL;

	wakeup_source_prepare(ws, name ? kstrdup(name, GFP_KERNEL) : NULL);
	return ws;
}

void wakeup_source_add(struct wakeup_source *ws)
{
	unsigned long flags;

	if (WARN_ON(!ws))
		return;

	spin_lock_init(&ws->lock);
	setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
	ws->active = false;
	ws->last_time = ktime_get();

	spin_lock_irqsave(&events_lock, flags);
	list_add_rcu(&ws->entry, &wakeup_sources);
	spin_unlock_irqrestore(&events_lock, flags);
}

static void pm_wakeup_timer_fn(unsigned long data)
{
	struct wakeup_source *ws = (struct wakeup_source *)data;
	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);
}

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;
	spin_unlock_irq(&dev->power.lock);
	return 0;
}

void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
{
	unsigned long flags;
	unsigned long expires;

	if (!ws)
		return;

	spin_lock_irqsave(&ws->lock, flags);

	wakeup_source_report_event(ws);

	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);
}

INIT_WORK(&bdata->work, gpio_keys_gpio_work_func);
setup_timer(&bdata->timer,gpio_keys_gpio_timer, (unsigned long)bdata);
device_init_wakeup(&pdev->dev, wakeup);

static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id)
{
    ...

	if (bdata->button->wakeup)
		pm_stay_awake(bdata->input->dev.parent);
    ...
    
	return IRQ_HANDLED;
}

static void gpio_keys_gpio_work_func(struct work_struct *work)
{
    gpio_keys_gpio_report_event(bdata);

	if (bdata->button->wakeup)
		pm_relax(bdata->input->dev.parent);

     ...
}