drivers/base/component.c - arm/linux-arm64-legacy - Git at Google

 /*
  * Componentized device handling.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * This is work in progress.  We gather up the component devices into a list,
  * and bind them when instructed.  At the moment, we're specific to the DRM
  * subsystem, and only handles one master device, but this doesn't have to be
  * the case.
  */
 #include <linux/component.h>
 #include <linux/device.h>
 #include <linux/kref.h>
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>

 struct master {
 	struct list_head node;
 	struct list_head components;
 	bool bound;

 	const struct component_master_ops *ops;
 	struct device *dev;
 };

 struct component {
 	struct list_head node;
 	struct list_head master_node;
 	struct master *master;
 	bool bound;

 	const struct component_ops *ops;
 	struct device *dev;
 };

 static DEFINE_MUTEX(component_mutex);
 static LIST_HEAD(component_list);
 static LIST_HEAD(masters);

 static struct master *__master_find(struct device *dev,
 	const struct component_master_ops *ops)
 {
 	struct master *m;

 	list_for_each_entry(m, &masters, node)
 		if (m->dev == dev && (!ops || m->ops == ops))
 			return m;

 	return NULL;
 }

 /* Attach an unattached component to a master. */
 static void component_attach_master(struct master *master, struct component *c)
 {
 	c->master = master;

 	list_add_tail(&c->master_node, &master->components);
 }

 /* Detach a component from a master. */
 static void component_detach_master(struct master *master, struct component *c)
 {
 	list_del(&c->master_node);

 	c->master = NULL;
 }

 int component_master_add_child(struct master *master,
 	int (*compare)(struct device *, void *), void *compare_data)
 {
 	struct component *c;
 	int ret = -ENXIO;

 	list_for_each_entry(c, &component_list, node) {
 		if (c->master)
 			continue;

 		if (compare(c->dev, compare_data)) {
 			component_attach_master(master, c);
 			ret = 0;
 			break;
 		}
 	}

 	return ret;
 }
 EXPORT_SYMBOL_GPL(component_master_add_child);

 /* Detach all attached components from this master */
 static void master_remove_components(struct master *master)
 {
 	while (!list_empty(&master->components)) {
 		struct component *c = list_first_entry(&master->components,
 					struct component, master_node);

 		WARN_ON(c->master != master);

 		component_detach_master(master, c);
 	}
 }

 /*
  * Try to bring up a master.  If component is NULL, we're interested in
  * this master, otherwise it's a component which must be present to try
  * and bring up the master.
  *
  * Returns 1 for successful bringup, 0 if not ready, or -ve errno.
  */
 static int try_to_bring_up_master(struct master *master,
 	struct component *component)
 {
 	int ret = 0;

 	if (!master->bound) {
 		/*
 		 * Search the list of components, looking for components that
 		 * belong to this master, and attach them to the master.
 		 */
 		if (master->ops->add_components(master->dev, master)) {
 			/* Failed to find all components */
 			master_remove_components(master);
 			ret = 0;
 			goto out;
 		}

 		if (component && component->master != master) {
 			master_remove_components(master);
 			ret = 0;
 			goto out;
 		}

 		if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) {
 			ret = -ENOMEM;
 			goto out;
 		}

 		/* Found all components */
 		ret = master->ops->bind(master->dev);
 		if (ret < 0) {
 			devres_release_group(master->dev, NULL);
 			dev_info(master->dev, "master bind failed: %d\n", ret);
 			master_remove_components(master);
 			goto out;
 		}

 		master->bound = true;
 		ret = 1;
 	}
 out:

 	return ret;
 }

 static int try_to_bring_up_masters(struct component *component)
 {
 	struct master *m;
 	int ret = 0;

 	list_for_each_entry(m, &masters, node) {
 		ret = try_to_bring_up_master(m, component);
 		if (ret != 0)
 			break;
 	}

 	return ret;
 }

 static void take_down_master(struct master *master)
 {
 	if (master->bound) {
 		master->ops->unbind(master->dev);
 		devres_release_group(master->dev, NULL);
 		master->bound = false;
 	}

 	master_remove_components(master);
 }

 int component_master_add(struct device *dev,
 	const struct component_master_ops *ops)
 {
 	struct master *master;
 	int ret;

 	master = kzalloc(sizeof(*master), GFP_KERNEL);
 	if (!master)
 		return -ENOMEM;

 	master->dev = dev;
 	master->ops = ops;
 	INIT_LIST_HEAD(&master->components);

 	/* Add to the list of available masters. */
 	mutex_lock(&component_mutex);
 	list_add(&master->node, &masters);

 	ret = try_to_bring_up_master(master, NULL);

 	if (ret < 0) {
 		/* Delete off the list if we weren't successful */
 		list_del(&master->node);
 		kfree(master);
 	}
 	mutex_unlock(&component_mutex);

 	return ret < 0 ? ret : 0;
 }
 EXPORT_SYMBOL_GPL(component_master_add);

 void component_master_del(struct device *dev,
 	const struct component_master_ops *ops)
 {
 	struct master *master;

 	mutex_lock(&component_mutex);
 	master = __master_find(dev, ops);
 	if (master) {
 		take_down_master(master);

 		list_del(&master->node);
 		kfree(master);
 	}
 	mutex_unlock(&component_mutex);
 }
 EXPORT_SYMBOL_GPL(component_master_del);

 static void component_unbind(struct component *component,
 	struct master *master, void *data)
 {
 	WARN_ON(!component->bound);

 	component->ops->unbind(component->dev, master->dev, data);
 	component->bound = false;

 	/* Release all resources claimed in the binding of this component */
 	devres_release_group(component->dev, component);
 }

 void component_unbind_all(struct device *master_dev, void *data)
 {
 	struct master *master;
 	struct component *c;

 	WARN_ON(!mutex_is_locked(&component_mutex));

 	master = __master_find(master_dev, NULL);
 	if (!master)
 		return;

 	list_for_each_entry_reverse(c, &master->components, master_node)
 		component_unbind(c, master, data);
 }
 EXPORT_SYMBOL_GPL(component_unbind_all);

 static int component_bind(struct component *component, struct master *master,
 	void *data)
 {
 	int ret;

 	/*
 	 * Each component initialises inside its own devres group.
 	 * This allows us to roll-back a failed component without
 	 * affecting anything else.
 	 */
 	if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
 		return -ENOMEM;

 	/*
 	 * Also open a group for the device itself: this allows us
 	 * to release the resources claimed against the sub-device
 	 * at the appropriate moment.
 	 */
 	if (!devres_open_group(component->dev, component, GFP_KERNEL)) {
 		devres_release_group(master->dev, NULL);
 		return -ENOMEM;
 	}

 	dev_dbg(master->dev, "binding %s (ops %ps)\n",
 		dev_name(component->dev), component->ops);

 	ret = component->ops->bind(component->dev, master->dev, data);
 	if (!ret) {
 		component->bound = true;

 		/*
 		 * Close the component device's group so that resources
 		 * allocated in the binding are encapsulated for removal
 		 * at unbind.  Remove the group on the DRM device as we
 		 * can clean those resources up independently.
 		 */
 		devres_close_group(component->dev, NULL);
 		devres_remove_group(master->dev, NULL);

 		dev_info(master->dev, "bound %s (ops %ps)\n",
 			 dev_name(component->dev), component->ops);
 	} else {
 		devres_release_group(component->dev, NULL);
 		devres_release_group(master->dev, NULL);

 		dev_err(master->dev, "failed to bind %s (ops %ps): %d\n",
 			dev_name(component->dev), component->ops, ret);
 	}

 	return ret;
 }

 int component_bind_all(struct device *master_dev, void *data)
 {
 	struct master *master;
 	struct component *c;
 	int ret = 0;

 	WARN_ON(!mutex_is_locked(&component_mutex));

 	master = __master_find(master_dev, NULL);
 	if (!master)
 		return -EINVAL;

 	list_for_each_entry(c, &master->components, master_node) {
 		ret = component_bind(c, master, data);
 		if (ret)
 			break;
 	}

 	if (ret != 0) {
 		list_for_each_entry_continue_reverse(c, &master->components,
 						     master_node)
 			component_unbind(c, master, data);
 	}

 	return ret;
 }
 EXPORT_SYMBOL_GPL(component_bind_all);

 int component_add(struct device *dev, const struct component_ops *ops)
 {
 	struct component *component;
 	int ret;

 	component = kzalloc(sizeof(*component), GFP_KERNEL);
 	if (!component)
 		return -ENOMEM;

 	component->ops = ops;
 	component->dev = dev;

 	dev_dbg(dev, "adding component (ops %ps)\n", ops);

 	mutex_lock(&component_mutex);
 	list_add_tail(&component->node, &component_list);

 	ret = try_to_bring_up_masters(component);
 	if (ret < 0) {
 		list_del(&component->node);

 		kfree(component);
 	}
 	mutex_unlock(&component_mutex);

 	return ret < 0 ? ret : 0;
 }
 EXPORT_SYMBOL_GPL(component_add);

 void component_del(struct device *dev, const struct component_ops *ops)
 {
 	struct component *c, *component = NULL;

 	mutex_lock(&component_mutex);
 	list_for_each_entry(c, &component_list, node)
 		if (c->dev == dev && c->ops == ops) {
 			list_del(&c->node);
 			component = c;
 			break;
 		}

 	if (component && component->master)
 		take_down_master(component->master);

 	mutex_unlock(&component_mutex);

 	WARN_ON(!component);
 	kfree(component);
 }
 EXPORT_SYMBOL_GPL(component_del);

 MODULE_LICENSE("GPL v2");
	/*
	* Componentized device handling.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* This is work in progress. We gather up the component devices into a list,
	* and bind them when instructed. At the moment, we're specific to the DRM
	* subsystem, and only handles one master device, but this doesn't have to be
	* the case.
	*/
	#include <linux/component.h>
	#include <linux/device.h>
	#include <linux/kref.h>
	#include <linux/list.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/slab.h>

	struct master {
	struct list_head node;
	struct list_head components;
	bool bound;

	const struct component_master_ops *ops;
	struct device *dev;
	};

	struct component {
	struct list_head node;
	struct list_head master_node;
	struct master *master;
	bool bound;

	const struct component_ops *ops;
	struct device *dev;
	};

	static DEFINE_MUTEX(component_mutex);
	static LIST_HEAD(component_list);
	static LIST_HEAD(masters);

	static struct master __master_find(struct device dev,
	const struct component_master_ops *ops)
	{
	struct master *m;

	list_for_each_entry(m, &masters, node)
	if (m->dev == dev && (!ops \|\| m->ops == ops))
	return m;

	return NULL;
	}

	/* Attach an unattached component to a master. */
	static void component_attach_master(struct master master, struct component c)
	{
	c->master = master;

	list_add_tail(&c->master_node, &master->components);
	}

	/* Detach a component from a master. */
	static void component_detach_master(struct master master, struct component c)
	{
	list_del(&c->master_node);

	c->master = NULL;
	}

	int component_master_add_child(struct master *master,
	int (compare)(struct device , void ), void compare_data)
	{
	struct component *c;
	int ret = -ENXIO;

	list_for_each_entry(c, &component_list, node) {
	if (c->master)
	continue;

	if (compare(c->dev, compare_data)) {
	component_attach_master(master, c);
	ret = 0;
	break;
	}
	}

	return ret;
	}
	EXPORT_SYMBOL_GPL(component_master_add_child);

	/* Detach all attached components from this master */
	static void master_remove_components(struct master *master)
	{
	while (!list_empty(&master->components)) {
	struct component *c = list_first_entry(&master->components,
	struct component, master_node);

	WARN_ON(c->master != master);

	component_detach_master(master, c);
	}
	}

	/*
	* Try to bring up a master. If component is NULL, we're interested in
	* this master, otherwise it's a component which must be present to try
	* and bring up the master.
	*
	* Returns 1 for successful bringup, 0 if not ready, or -ve errno.
	*/
	static int try_to_bring_up_master(struct master *master,
	struct component *component)
	{
	int ret = 0;

	if (!master->bound) {
	/*
	* Search the list of components, looking for components that
	* belong to this master, and attach them to the master.
	*/
	if (master->ops->add_components(master->dev, master)) {
	/* Failed to find all components */
	master_remove_components(master);
	ret = 0;
	goto out;
	}

	if (component && component->master != master) {
	master_remove_components(master);
	ret = 0;
	goto out;
	}

	if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) {
	ret = -ENOMEM;
	goto out;
	}

	/* Found all components */
	ret = master->ops->bind(master->dev);
	if (ret < 0) {
	devres_release_group(master->dev, NULL);
	dev_info(master->dev, "master bind failed: %d\n", ret);
	master_remove_components(master);
	goto out;
	}

	master->bound = true;
	ret = 1;
	}
	out:

	return ret;
	}

	static int try_to_bring_up_masters(struct component *component)
	{
	struct master *m;
	int ret = 0;

	list_for_each_entry(m, &masters, node) {
	ret = try_to_bring_up_master(m, component);
	if (ret != 0)
	break;
	}

	return ret;
	}

	static void take_down_master(struct master *master)
	{
	if (master->bound) {
	master->ops->unbind(master->dev);
	devres_release_group(master->dev, NULL);
	master->bound = false;
	}

	master_remove_components(master);
	}

	int component_master_add(struct device *dev,
	const struct component_master_ops *ops)
	{
	struct master *master;
	int ret;

	master = kzalloc(sizeof(*master), GFP_KERNEL);
	if (!master)
	return -ENOMEM;

	master->dev = dev;
	master->ops = ops;
	INIT_LIST_HEAD(&master->components);

	/* Add to the list of available masters. */
	mutex_lock(&component_mutex);
	list_add(&master->node, &masters);

	ret = try_to_bring_up_master(master, NULL);

	if (ret < 0) {
	/* Delete off the list if we weren't successful */
	list_del(&master->node);
	kfree(master);
	}
	mutex_unlock(&component_mutex);

	return ret < 0 ? ret : 0;
	}
	EXPORT_SYMBOL_GPL(component_master_add);

	void component_master_del(struct device *dev,
	const struct component_master_ops *ops)
	{
	struct master *master;

	mutex_lock(&component_mutex);
	master = __master_find(dev, ops);
	if (master) {
	take_down_master(master);

	list_del(&master->node);
	kfree(master);
	}
	mutex_unlock(&component_mutex);
	}
	EXPORT_SYMBOL_GPL(component_master_del);

	static void component_unbind(struct component *component,
	struct master master, void data)
	{
	WARN_ON(!component->bound);

	component->ops->unbind(component->dev, master->dev, data);
	component->bound = false;

	/* Release all resources claimed in the binding of this component */
	devres_release_group(component->dev, component);
	}

	void component_unbind_all(struct device master_dev, void data)
	{
	struct master *master;
	struct component *c;

	WARN_ON(!mutex_is_locked(&component_mutex));

	master = __master_find(master_dev, NULL);
	if (!master)
	return;

	list_for_each_entry_reverse(c, &master->components, master_node)
	component_unbind(c, master, data);
	}
	EXPORT_SYMBOL_GPL(component_unbind_all);

	static int component_bind(struct component component, struct master master,
	void *data)
	{
	int ret;

	/*
	* Each component initialises inside its own devres group.
	* This allows us to roll-back a failed component without
	* affecting anything else.
	*/
	if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
	return -ENOMEM;

	/*
	* Also open a group for the device itself: this allows us
	* to release the resources claimed against the sub-device
	* at the appropriate moment.
	*/
	if (!devres_open_group(component->dev, component, GFP_KERNEL)) {
	devres_release_group(master->dev, NULL);
	return -ENOMEM;
	}

	dev_dbg(master->dev, "binding %s (ops %ps)\n",
	dev_name(component->dev), component->ops);

	ret = component->ops->bind(component->dev, master->dev, data);
	if (!ret) {
	component->bound = true;

	/*
	* Close the component device's group so that resources
	* allocated in the binding are encapsulated for removal
	* at unbind. Remove the group on the DRM device as we
	* can clean those resources up independently.
	*/
	devres_close_group(component->dev, NULL);
	devres_remove_group(master->dev, NULL);

	dev_info(master->dev, "bound %s (ops %ps)\n",
	dev_name(component->dev), component->ops);
	} else {
	devres_release_group(component->dev, NULL);
	devres_release_group(master->dev, NULL);

	dev_err(master->dev, "failed to bind %s (ops %ps): %d\n",
	dev_name(component->dev), component->ops, ret);
	}

	return ret;
	}

	int component_bind_all(struct device master_dev, void data)
	{
	struct master *master;
	struct component *c;
	int ret = 0;

	WARN_ON(!mutex_is_locked(&component_mutex));

	master = __master_find(master_dev, NULL);
	if (!master)
	return -EINVAL;

	list_for_each_entry(c, &master->components, master_node) {
	ret = component_bind(c, master, data);
	if (ret)
	break;
	}

	if (ret != 0) {
	list_for_each_entry_continue_reverse(c, &master->components,
	master_node)
	component_unbind(c, master, data);
	}

	return ret;
	}
	EXPORT_SYMBOL_GPL(component_bind_all);

	int component_add(struct device dev, const struct component_ops ops)
	{
	struct component *component;
	int ret;

	component = kzalloc(sizeof(*component), GFP_KERNEL);
	if (!component)
	return -ENOMEM;

	component->ops = ops;
	component->dev = dev;

	dev_dbg(dev, "adding component (ops %ps)\n", ops);

	mutex_lock(&component_mutex);
	list_add_tail(&component->node, &component_list);

	ret = try_to_bring_up_masters(component);
	if (ret < 0) {
	list_del(&component->node);

	kfree(component);
	}
	mutex_unlock(&component_mutex);

	return ret < 0 ? ret : 0;
	}
	EXPORT_SYMBOL_GPL(component_add);

	void component_del(struct device dev, const struct component_ops ops)
	{
	struct component c, component = NULL;

	mutex_lock(&component_mutex);
	list_for_each_entry(c, &component_list, node)
	if (c->dev == dev && c->ops == ops) {
	list_del(&c->node);
	component = c;
	break;
	}

	if (component && component->master)
	take_down_master(component->master);

	mutex_unlock(&component_mutex);

	WARN_ON(!component);
	kfree(component);
	}
	EXPORT_SYMBOL_GPL(component_del);

	MODULE_LICENSE("GPL v2");