PM / devfreq: Core updates to support devices which can idle (7e6fdd4b) · Commits · 戴 / test

Documentation/ABI/testing/sysfs-class-devfreq

+0 −8

Original line number	Diff line number	Diff line
		@@ -21,14 +21,6 @@ Description:
		The /sys/class/devfreq/.../cur_freq shows the current
		frequency of the corresponding devfreq object.

		What: /sys/class/devfreq/.../central_polling
		Date: September 2011
		Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
		Description:
		The /sys/class/devfreq/.../central_polling shows whether
		the devfreq ojbect is using devfreq-provided central
		polling mechanism or not.

		What: /sys/class/devfreq/.../polling_interval
		Date: September 2011
		Contact: MyungJoo Ham <myungjoo.ham@samsung.com>

drivers/devfreq/devfreq.c

+189 −253

Original line number	Diff line number	Diff line
		@@ -30,17 +30,11 @@
		struct class *devfreq_class;

		/*
		* devfreq_work periodically monitors every registered device.
		* The minimum polling interval is one jiffy. The polling interval is
		* determined by the minimum polling period among all polling devfreq
		* devices. The resolution of polling interval is one jiffy.
		* devfreq core provides delayed work based load monitoring helper
		* functions. Governors can use these or can implement their own
		* monitoring mechanism.
		*/
		static bool polling;
		static struct workqueue_struct *devfreq_wq;
		static struct delayed_work devfreq_work;

		/* wait removing if this is to be removed */
		static struct devfreq *wait_remove_device;

		/* The list of all device-devfreq */
		static LIST_HEAD(devfreq_list);
		@@ -72,6 +66,8 @@ static struct devfreq find_device_devfreq(struct device dev)
		return ERR_PTR(-ENODEV);
		}

		/* Load monitoring helper functions for governors use */

		/**
		* update_devfreq() - Reevaluate the device and configure frequency.
		* @devfreq: the devfreq instance.
		@@ -121,219 +117,216 @@ int update_devfreq(struct devfreq *devfreq)
		}

		/**
		* devfreq_notifier_call() - Notify that the device frequency requirements
		* has been changed out of devfreq framework.
		* @nb the notifier_block (supposed to be devfreq->nb)
		* @type not used
		* @devp not used
		* devfreq_monitor() - Periodically poll devfreq objects.
		* @work: the work struct used to run devfreq_monitor periodically.
		*
		* Called by a notifier that uses devfreq->nb.
		*/
		static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
		void *devp)
		static void devfreq_monitor(struct work_struct *work)
		{
		struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
		int ret;
		int err;
		struct devfreq *devfreq = container_of(work,
		struct devfreq, work.work);

		mutex_lock(&devfreq->lock);
		ret = update_devfreq(devfreq);
		mutex_unlock(&devfreq->lock);
		err = update_devfreq(devfreq);
		if (err)
		dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);

		return ret;
		queue_delayed_work(devfreq_wq, &devfreq->work,
		msecs_to_jiffies(devfreq->profile->polling_ms));
		mutex_unlock(&devfreq->lock);
		}

		/**
		* _remove_devfreq() - Remove devfreq from the device.
		* @devfreq: the devfreq struct
		* @skip: skip calling device_unregister().
		*
		* Note that the caller should lock devfreq->lock before calling
		* this. _remove_devfreq() will unlock it and free devfreq
		* internally. devfreq_list_lock should be locked by the caller
		* as well (not relased at return)
		*
		* Lock usage:
		* devfreq->lock: locked before call.
		* unlocked at return (and freed)
		* devfreq_list_lock: locked before call.
		* kept locked at return.
		* if devfreq is centrally polled.
		* devfreq_monitor_start() - Start load monitoring of devfreq instance
		* @devfreq: the devfreq instance.
		*
		* Freed memory:
		* devfreq
		* Helper function for starting devfreq device load monitoing. By
		* default delayed work based monitoring is supported. Function
		* to be called from governor in response to DEVFREQ_GOV_START
		* event when device is added to devfreq framework.
		*/
		static void _remove_devfreq(struct devfreq *devfreq, bool skip)
		void devfreq_monitor_start(struct devfreq *devfreq)
		{
		if (!mutex_is_locked(&devfreq->lock)) {
		WARN(true, "devfreq->lock must be locked by the caller.\n");
		return;
		INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
		if (devfreq->profile->polling_ms)
		queue_delayed_work(devfreq_wq, &devfreq->work,
		msecs_to_jiffies(devfreq->profile->polling_ms));
		}
		if (!devfreq->governor->no_central_polling &&
		!mutex_is_locked(&devfreq_list_lock)) {
		WARN(true, "devfreq_list_lock must be locked by the caller.\n");
		return;

		/**
		* devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
		* @devfreq: the devfreq instance.
		*
		* Helper function to stop devfreq device load monitoing. Function
		* to be called from governor in response to DEVFREQ_GOV_STOP
		* event when device is removed from devfreq framework.
		*/
		void devfreq_monitor_stop(struct devfreq *devfreq)
		{
		cancel_delayed_work_sync(&devfreq->work);
		}

		if (devfreq->being_removed)
		/**
		* devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
		* @devfreq: the devfreq instance.
		*
		* Helper function to suspend devfreq device load monitoing. Function
		* to be called from governor in response to DEVFREQ_GOV_SUSPEND
		* event or when polling interval is set to zero.
		*
		* Note: Though this function is same as devfreq_monitor_stop(),
		* intentionally kept separate to provide hooks for collecting
		* transition statistics.
		*/
		void devfreq_monitor_suspend(struct devfreq *devfreq)
		{
		mutex_lock(&devfreq->lock);
		if (devfreq->stop_polling) {
		mutex_unlock(&devfreq->lock);
		return;

		devfreq->being_removed = true;

		if (devfreq->profile->exit)
		devfreq->profile->exit(devfreq->dev.parent);

		if (devfreq->governor->exit)
		devfreq->governor->exit(devfreq);

		if (!skip && get_device(&devfreq->dev)) {
		device_unregister(&devfreq->dev);
		put_device(&devfreq->dev);
		}

		if (!devfreq->governor->no_central_polling)
		list_del(&devfreq->node);

		devfreq->stop_polling = true;
		mutex_unlock(&devfreq->lock);
		mutex_destroy(&devfreq->lock);

		kfree(devfreq);
		cancel_delayed_work_sync(&devfreq->work);
		}

		/**
		* devfreq_dev_release() - Callback for struct device to release the device.
		* @dev: the devfreq device
		* devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
		* @devfreq: the devfreq instance.
		*
		* This calls _remove_devfreq() if _remove_devfreq() is not called.
		* Note that devfreq_dev_release() could be called by _remove_devfreq() as
		* well as by others unregistering the device.
		* Helper function to resume devfreq device load monitoing. Function
		* to be called from governor in response to DEVFREQ_GOV_RESUME
		* event or when polling interval is set to non-zero.
		*/
		static void devfreq_dev_release(struct device *dev)
		void devfreq_monitor_resume(struct devfreq *devfreq)
		{
		struct devfreq *devfreq = to_devfreq(dev);
		bool central_polling = !devfreq->governor->no_central_polling;

		/*
		* If devfreq_dev_release() was called by device_unregister() of
		* _remove_devfreq(), we cannot mutex_lock(&devfreq->lock) and
		* being_removed is already set. This also partially checks the case
		* where devfreq_dev_release() is called from a thread other than
		* the one called _remove_devfreq(); however, this case is
		* dealt completely with another following being_removed check.
		*
		* Because being_removed is never being
		* unset, we do not need to worry about race conditions on
		* being_removed.
		*/
		if (devfreq->being_removed)
		return;

		if (central_polling)
		mutex_lock(&devfreq_list_lock);

		mutex_lock(&devfreq->lock);

		/*
		* Check being_removed flag again for the case where
		* devfreq_dev_release() was called in a thread other than the one
		* possibly called _remove_devfreq().
		*/
		if (devfreq->being_removed) {
		mutex_unlock(&devfreq->lock);
		if (!devfreq->stop_polling)
		goto out;
		}

		/* devfreq->lock is unlocked and removed in _removed_devfreq() */
		_remove_devfreq(devfreq, true);
		if (!delayed_work_pending(&devfreq->work) &&
		devfreq->profile->polling_ms)
		queue_delayed_work(devfreq_wq, &devfreq->work,
		msecs_to_jiffies(devfreq->profile->polling_ms));
		devfreq->stop_polling = false;

		out:
		if (central_polling)
		mutex_unlock(&devfreq_list_lock);
		mutex_unlock(&devfreq->lock);
		}

		/**
		* devfreq_monitor() - Periodically poll devfreq objects.
		* @work: the work struct used to run devfreq_monitor periodically.
		* devfreq_interval_update() - Update device devfreq monitoring interval
		* @devfreq: the devfreq instance.
		* @delay: new polling interval to be set.
		*
		* Helper function to set new load monitoring polling interval. Function
		* to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
		*/
		static void devfreq_monitor(struct work_struct *work)
		void devfreq_interval_update(struct devfreq devfreq, unsigned int delay)
		{
		static unsigned long last_polled_at;
		struct devfreq devfreq, tmp;
		int error;
		unsigned long jiffies_passed;
		unsigned long next_jiffies = ULONG_MAX, now = jiffies;
		struct device *dev;

		/* Initially last_polled_at = 0, polling every device at bootup */
		jiffies_passed = now - last_polled_at;
		last_polled_at = now;
		if (jiffies_passed == 0)
		jiffies_passed = 1;
		unsigned int cur_delay = devfreq->profile->polling_ms;
		unsigned int new_delay = *delay;

		mutex_lock(&devfreq_list_lock);
		list_for_each_entry_safe(devfreq, tmp, &devfreq_list, node) {
		mutex_lock(&devfreq->lock);
		dev = devfreq->dev.parent;
		devfreq->profile->polling_ms = new_delay;

		/* Do not remove tmp for a while */
		wait_remove_device = tmp;
		if (devfreq->stop_polling)
		goto out;

		if (devfreq->governor->no_central_polling \|\|
		devfreq->next_polling == 0) {
		/* if new delay is zero, stop polling */
		if (!new_delay) {
		mutex_unlock(&devfreq->lock);
		continue;
		cancel_delayed_work_sync(&devfreq->work);
		return;
		}
		mutex_unlock(&devfreq_list_lock);

		/*
		* Reduce more next_polling if devfreq_wq took an extra
		* delay. (i.e., CPU has been idled.)
		*/
		if (devfreq->next_polling <= jiffies_passed) {
		error = update_devfreq(devfreq);

		/* Remove a devfreq with an error. */
		if (error && error != -EAGAIN) {

		dev_err(dev, "Due to update_devfreq error(%d), devfreq(%s) is removed from the device\n",
		error, devfreq->governor->name);
		/* if current delay is zero, start polling with new delay */
		if (!cur_delay) {
		queue_delayed_work(devfreq_wq, &devfreq->work,
		msecs_to_jiffies(devfreq->profile->polling_ms));
		goto out;
		}

		/*
		* Unlock devfreq before locking the list
		* in order to avoid deadlock with
		* find_device_devfreq or others
		*/
		/* if current delay is greater than new delay, restart polling */
		if (cur_delay > new_delay) {
		mutex_unlock(&devfreq->lock);
		mutex_lock(&devfreq_list_lock);
		/* Check if devfreq is already removed */
		if (IS_ERR(find_device_devfreq(dev)))
		continue;
		cancel_delayed_work_sync(&devfreq->work);
		mutex_lock(&devfreq->lock);
		/* This unlocks devfreq->lock and free it */
		_remove_devfreq(devfreq, false);
		continue;
		if (!devfreq->stop_polling)
		queue_delayed_work(devfreq_wq, &devfreq->work,
		msecs_to_jiffies(devfreq->profile->polling_ms));
		}
		devfreq->next_polling = devfreq->polling_jiffies;
		} else {
		devfreq->next_polling -= jiffies_passed;
		out:
		mutex_unlock(&devfreq->lock);
		}

		if (devfreq->next_polling)
		next_jiffies = (next_jiffies > devfreq->next_polling) ?
		devfreq->next_polling : next_jiffies;
		/**
		* devfreq_notifier_call() - Notify that the device frequency requirements
		* has been changed out of devfreq framework.
		* @nb the notifier_block (supposed to be devfreq->nb)
		* @type not used
		* @devp not used
		*
		* Called by a notifier that uses devfreq->nb.
		*/
		static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
		void *devp)
		{
		struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
		int ret;

		mutex_lock(&devfreq->lock);
		ret = update_devfreq(devfreq);
		mutex_unlock(&devfreq->lock);

		return ret;
		}

		/**
		* _remove_devfreq() - Remove devfreq from the list and release its resources.
		* @devfreq: the devfreq struct
		* @skip: skip calling device_unregister().
		*/
		static void _remove_devfreq(struct devfreq *devfreq, bool skip)
		{
		mutex_lock(&devfreq_list_lock);
		if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
		mutex_unlock(&devfreq_list_lock);
		dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
		return;
		}
		wait_remove_device = NULL;
		list_del(&devfreq->node);
		mutex_unlock(&devfreq_list_lock);

		if (next_jiffies > 0 && next_jiffies < ULONG_MAX) {
		polling = true;
		queue_delayed_work(devfreq_wq, &devfreq_work, next_jiffies);
		} else {
		polling = false;
		devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_STOP, NULL);

		if (devfreq->profile->exit)
		devfreq->profile->exit(devfreq->dev.parent);

		if (!skip && get_device(&devfreq->dev)) {
		device_unregister(&devfreq->dev);
		put_device(&devfreq->dev);
		}

		mutex_destroy(&devfreq->lock);
		kfree(devfreq);
		}

		/**
		* devfreq_dev_release() - Callback for struct device to release the device.
		* @dev: the devfreq device
		*
		* This calls _remove_devfreq() if _remove_devfreq() is not called.
		* Note that devfreq_dev_release() could be called by _remove_devfreq() as
		* well as by others unregistering the device.
		*/
		static void devfreq_dev_release(struct device *dev)
		{
		struct devfreq *devfreq = to_devfreq(dev);

		_remove_devfreq(devfreq, true);
		}

		/**
		@@ -357,8 +350,6 @@ struct devfreq devfreq_add_device(struct device dev,
		return ERR_PTR(-EINVAL);
		}


		if (!governor->no_central_polling) {
		mutex_lock(&devfreq_list_lock);
		devfreq = find_device_devfreq(dev);
		mutex_unlock(&devfreq_list_lock);
		@@ -367,7 +358,6 @@ struct devfreq devfreq_add_device(struct device dev,
		err = -EINVAL;
		goto err_out;
		}
		}

		devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
		if (!devfreq) {
		@@ -386,48 +376,41 @@ struct devfreq devfreq_add_device(struct device dev,
		devfreq->governor = governor;
		devfreq->previous_freq = profile->initial_freq;
		devfreq->data = data;
		devfreq->next_polling = devfreq->polling_jiffies
		= msecs_to_jiffies(devfreq->profile->polling_ms);
		devfreq->nb.notifier_call = devfreq_notifier_call;

		dev_set_name(&devfreq->dev, dev_name(dev));
		err = device_register(&devfreq->dev);
		if (err) {
		put_device(&devfreq->dev);
		mutex_unlock(&devfreq->lock);
		goto err_dev;
		}

		if (governor->init)
		err = governor->init(devfreq);
		if (err)
		goto err_init;

		mutex_unlock(&devfreq->lock);

		if (governor->no_central_polling)
		goto out;

		mutex_lock(&devfreq_list_lock);

		list_add(&devfreq->node, &devfreq_list);
		mutex_unlock(&devfreq_list_lock);

		if (devfreq_wq && devfreq->next_polling && !polling) {
		polling = true;
		queue_delayed_work(devfreq_wq, &devfreq_work,
		devfreq->next_polling);
		err = devfreq->governor->event_handler(devfreq,
		DEVFREQ_GOV_START, NULL);
		if (err) {
		dev_err(dev, "%s: Unable to start governor for the device\n",
		__func__);
		goto err_init;
		}
		mutex_unlock(&devfreq_list_lock);
		out:

		return devfreq;

		err_init:
		list_del(&devfreq->node);
		device_unregister(&devfreq->dev);
		err_dev:
		mutex_unlock(&devfreq->lock);
		kfree(devfreq);
		err_out:
		return ERR_PTR(err);
		}
		EXPORT_SYMBOL(devfreq_add_device);

		/**
		* devfreq_remove_device() - Remove devfreq feature from a device.
		@@ -435,30 +418,14 @@ err_out:
		*/
		int devfreq_remove_device(struct devfreq *devfreq)
		{
		bool central_polling;

		if (!devfreq)
		return -EINVAL;

		central_polling = !devfreq->governor->no_central_polling;

		if (central_polling) {
		mutex_lock(&devfreq_list_lock);
		while (wait_remove_device == devfreq) {
		mutex_unlock(&devfreq_list_lock);
		schedule();
		mutex_lock(&devfreq_list_lock);
		}
		}

		mutex_lock(&devfreq->lock);
		_remove_devfreq(devfreq, false); /* it unlocks devfreq->lock */

		if (central_polling)
		mutex_unlock(&devfreq_list_lock);
		_remove_devfreq(devfreq, false);

		return 0;
		}
		EXPORT_SYMBOL(devfreq_remove_device);

		static ssize_t show_governor(struct device *dev,
		struct device_attribute attr, char buf)
		@@ -490,35 +457,13 @@ static ssize_t store_polling_interval(struct device *dev,
		if (ret != 1)
		goto out;

		mutex_lock(&df->lock);
		df->profile->polling_ms = value;
		df->next_polling = df->polling_jiffies
		= msecs_to_jiffies(value);
		mutex_unlock(&df->lock);

		df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
		ret = count;

		if (df->governor->no_central_polling)
		goto out;

		mutex_lock(&devfreq_list_lock);
		if (df->next_polling > 0 && !polling) {
		polling = true;
		queue_delayed_work(devfreq_wq, &devfreq_work,
		df->next_polling);
		}
		mutex_unlock(&devfreq_list_lock);
		out:
		return ret;
		}

		static ssize_t show_central_polling(struct device *dev,
		struct device_attribute attr, char buf)
		{
		return sprintf(buf, "%d\n",
		!to_devfreq(dev)->governor->no_central_polling);
		}

		static ssize_t store_min_freq(struct device dev, struct device_attribute attr,
		const char *buf, size_t count)
		{
		@@ -590,7 +535,6 @@ static ssize_t show_max_freq(struct device dev, struct device_attribute attr,
		static struct device_attribute devfreq_attrs[] = {
		__ATTR(governor, S_IRUGO, show_governor, NULL),
		__ATTR(cur_freq, S_IRUGO, show_freq, NULL),
		__ATTR(central_polling, S_IRUGO, show_central_polling, NULL),
		__ATTR(polling_interval, S_IRUGO \| S_IWUSR, show_polling_interval,
		store_polling_interval),
		__ATTR(min_freq, S_IRUGO \| S_IWUSR, show_min_freq, store_min_freq),
		@@ -598,23 +542,6 @@ static struct device_attribute devfreq_attrs[] = {
		{ },
		};

		/**
		* devfreq_start_polling() - Initialize data structure for devfreq framework and
		* start polling registered devfreq devices.
		*/
		static int __init devfreq_start_polling(void)
		{
		mutex_lock(&devfreq_list_lock);
		polling = false;
		devfreq_wq = create_freezable_workqueue("devfreq_wq");
		INIT_DEFERRABLE_WORK(&devfreq_work, devfreq_monitor);
		mutex_unlock(&devfreq_list_lock);

		devfreq_monitor(&devfreq_work.work);
		return 0;
		}
		late_initcall(devfreq_start_polling);

		static int __init devfreq_init(void)
		{
		devfreq_class = class_create(THIS_MODULE, "devfreq");
		@@ -622,7 +549,15 @@ static int __init devfreq_init(void)
		pr_err("%s: couldn't create class\n", __FILE__);
		return PTR_ERR(devfreq_class);
		}

		devfreq_wq = create_freezable_workqueue("devfreq_wq");
		if (IS_ERR(devfreq_wq)) {
		class_destroy(devfreq_class);
		pr_err("%s: couldn't create workqueue\n", __FILE__);
		return PTR_ERR(devfreq_wq);
		}
		devfreq_class->dev_attrs = devfreq_attrs;

		return 0;
		}
		subsys_initcall(devfreq_init);
		@@ -630,6 +565,7 @@ subsys_initcall(devfreq_init);
		static void __exit devfreq_exit(void)
		{
		class_destroy(devfreq_class);
		destroy_workqueue(devfreq_wq);
		}
		module_exit(devfreq_exit);

drivers/devfreq/governor.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -18,7 +18,18 @@

		#define to_devfreq(DEV) container_of((DEV), struct devfreq, dev)

		/* Devfreq events */
		#define DEVFREQ_GOV_START 0x1
		#define DEVFREQ_GOV_STOP 0x2
		#define DEVFREQ_GOV_INTERVAL 0x3

		/* Caution: devfreq->lock must be locked before calling update_devfreq */
		extern int update_devfreq(struct devfreq *devfreq);

		extern void devfreq_monitor_start(struct devfreq *devfreq);
		extern void devfreq_monitor_stop(struct devfreq *devfreq);
		extern void devfreq_monitor_suspend(struct devfreq *devfreq);
		extern void devfreq_monitor_resume(struct devfreq *devfreq);
		extern void devfreq_interval_update(struct devfreq *devfreq,
		unsigned int *delay);
		#endif /* _GOVERNOR_H */

drivers/devfreq/governor_performance.c

+12 −4

Original line number	Diff line number	Diff line
		@@ -26,14 +26,22 @@ static int devfreq_performance_func(struct devfreq *df,
		return 0;
		}

		static int performance_init(struct devfreq *devfreq)
		static int devfreq_performance_handler(struct devfreq *devfreq,
		unsigned int event, void *data)
		{
		return update_devfreq(devfreq);
		int ret = 0;

		if (event == DEVFREQ_GOV_START) {
		mutex_lock(&devfreq->lock);
		ret = update_devfreq(devfreq);
		mutex_unlock(&devfreq->lock);
		}

		return ret;
		}

		const struct devfreq_governor devfreq_performance = {
		.name = "performance",
		.init = performance_init,
		.get_target_freq = devfreq_performance_func,
		.no_central_polling = true,
		.event_handler = devfreq_performance_handler,
		};

drivers/devfreq/governor_powersave.c

+12 −4

Original line number	Diff line number	Diff line
		@@ -23,14 +23,22 @@ static int devfreq_powersave_func(struct devfreq *df,
		return 0;
		}

		static int powersave_init(struct devfreq *devfreq)
		static int devfreq_powersave_handler(struct devfreq *devfreq,
		unsigned int event, void *data)
		{
		return update_devfreq(devfreq);
		int ret = 0;

		if (event == DEVFREQ_GOV_START) {
		mutex_lock(&devfreq->lock);
		ret = update_devfreq(devfreq);
		mutex_unlock(&devfreq->lock);
		}

		return ret;
		}

		const struct devfreq_governor devfreq_powersave = {
		.name = "powersave",
		.init = powersave_init,
		.get_target_freq = devfreq_powersave_func,
		.no_central_polling = true,
		.event_handler = devfreq_powersave_handler,
		};

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