drivers/base/core.c - kernel/msm-4.19 - Gitiles

 /*
  * drivers/base/core.c - core driver model code (device registration, etc)
  *
  * Copyright (c) 2002-3 Patrick Mochel
  * Copyright (c) 2002-3 Open Source Development Labs
  *
  * This file is released under the GPLv2
  *
  */

 #include <linux/config.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/string.h>

 #include <asm/semaphore.h>

 #include "base.h"
 #include "power/power.h"

 int (*platform_notify)(struct device * dev) = NULL;
 int (*platform_notify_remove)(struct device * dev) = NULL;

 /*
  * sysfs bindings for devices.
  */

 #define to_dev(obj) container_of(obj, struct device, kobj)
 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)

 static ssize_t
 dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
 {
 	struct device_attribute * dev_attr = to_dev_attr(attr);
 	struct device * dev = to_dev(kobj);
 	ssize_t ret = -EIO;

 	if (dev_attr->show)
 		ret = dev_attr->show(dev, buf);
 	return ret;
 }

 static ssize_t
 dev_attr_store(struct kobject * kobj, struct attribute * attr,
 	       const char * buf, size_t count)
 {
 	struct device_attribute * dev_attr = to_dev_attr(attr);
 	struct device * dev = to_dev(kobj);
 	ssize_t ret = -EIO;

 	if (dev_attr->store)
 		ret = dev_attr->store(dev, buf, count);
 	return ret;
 }

 static struct sysfs_ops dev_sysfs_ops = {
 	.show	= dev_attr_show,
 	.store	= dev_attr_store,
 };


 /**
  *	device_release - free device structure.
  *	@kobj:	device's kobject.
  *
  *	This is called once the reference count for the object
  *	reaches 0. We forward the call to the device's release
  *	method, which should handle actually freeing the structure.
  */
 static void device_release(struct kobject * kobj)
 {
 	struct device * dev = to_dev(kobj);

 	if (dev->release)
 		dev->release(dev);
 	else {
 		printk(KERN_ERR "Device '%s' does not have a release() function, "
 			"it is broken and must be fixed.\n",
 			dev->bus_id);
 		WARN_ON(1);
 	}
 }

 static struct kobj_type ktype_device = {
 	.release	= device_release,
 	.sysfs_ops	= &dev_sysfs_ops,
 };


 static int dev_hotplug_filter(struct kset *kset, struct kobject *kobj)
 {
 	struct kobj_type *ktype = get_ktype(kobj);

 	if (ktype == &ktype_device) {
 		struct device *dev = to_dev(kobj);
 		if (dev->bus)
 			return 1;
 	}
 	return 0;
 }

 static const char *dev_hotplug_name(struct kset *kset, struct kobject *kobj)
 {
 	struct device *dev = to_dev(kobj);

 	return dev->bus->name;
 }

 static int dev_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
 			int num_envp, char *buffer, int buffer_size)
 {
 	struct device *dev = to_dev(kobj);
 	int i = 0;
 	int length = 0;
 	int retval = 0;

 	/* add bus name of physical device */
 	if (dev->bus)
 		add_hotplug_env_var(envp, num_envp, &i,
 				    buffer, buffer_size, &length,
 				    "PHYSDEVBUS=%s", dev->bus->name);

 	/* add driver name of physical device */
 	if (dev->driver)
 		add_hotplug_env_var(envp, num_envp, &i,
 				    buffer, buffer_size, &length,
 				    "PHYSDEVDRIVER=%s", dev->driver->name);

 	/* terminate, set to next free slot, shrink available space */
 	envp[i] = NULL;
 	envp = &envp[i];
 	num_envp -= i;
 	buffer = &buffer[length];
 	buffer_size -= length;

 	if (dev->bus && dev->bus->hotplug) {
 		/* have the bus specific function add its stuff */
 		retval = dev->bus->hotplug (dev, envp, num_envp, buffer, buffer_size);
 			if (retval) {
 			pr_debug ("%s - hotplug() returned %d\n",
 				  __FUNCTION__, retval);
 		}
 	}

 	return retval;
 }

 static struct kset_hotplug_ops device_hotplug_ops = {
 	.filter =	dev_hotplug_filter,
 	.name =		dev_hotplug_name,
 	.hotplug =	dev_hotplug,
 };

 /**
  *	device_subsys - structure to be registered with kobject core.
  */

 decl_subsys(devices, &ktype_device, &device_hotplug_ops);


 /**
  *	device_create_file - create sysfs attribute file for device.
  *	@dev:	device.
  *	@attr:	device attribute descriptor.
  */

 int device_create_file(struct device * dev, struct device_attribute * attr)
 {
 	int error = 0;
 	if (get_device(dev)) {
 		error = sysfs_create_file(&dev->kobj, &attr->attr);
 		put_device(dev);
 	}
 	return error;
 }

 /**
  *	device_remove_file - remove sysfs attribute file.
  *	@dev:	device.
  *	@attr:	device attribute descriptor.
  */

 void device_remove_file(struct device * dev, struct device_attribute * attr)
 {
 	if (get_device(dev)) {
 		sysfs_remove_file(&dev->kobj, &attr->attr);
 		put_device(dev);
 	}
 }


 /**
  *	device_initialize - init device structure.
  *	@dev:	device.
  *
  *	This prepares the device for use by other layers,
  *	including adding it to the device hierarchy.
  *	It is the first half of device_register(), if called by
  *	that, though it can also be called separately, so one
  *	may use @dev's fields (e.g. the refcount).
  */

 void device_initialize(struct device *dev)
 {
 	kobj_set_kset_s(dev, devices_subsys);
 	kobject_init(&dev->kobj);
 	INIT_LIST_HEAD(&dev->node);
 	INIT_LIST_HEAD(&dev->children);
 	INIT_LIST_HEAD(&dev->driver_list);
 	INIT_LIST_HEAD(&dev->bus_list);
 	INIT_LIST_HEAD(&dev->dma_pools);
 }

 /**
  *	device_add - add device to device hierarchy.
  *	@dev:	device.
  *
  *	This is part 2 of device_register(), though may be called
  *	separately _iff_ device_initialize() has been called separately.
  *
  *	This adds it to the kobject hierarchy via kobject_add(), adds it
  *	to the global and sibling lists for the device, then
  *	adds it to the other relevant subsystems of the driver model.
  */
 int device_add(struct device *dev)
 {
 	struct device *parent = NULL;
 	int error = -EINVAL;

 	dev = get_device(dev);
 	if (!dev || !strlen(dev->bus_id))
 		goto Error;

 	parent = get_device(dev->parent);

 	pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);

 	/* first, register with generic layer. */
 	kobject_set_name(&dev->kobj, "%s", dev->bus_id);
 	if (parent)
 		dev->kobj.parent = &parent->kobj;

 	if ((error = kobject_add(&dev->kobj)))
 		goto Error;
 	kobject_hotplug(&dev->kobj, KOBJ_ADD);
 	if ((error = device_pm_add(dev)))
 		goto PMError;
 	if ((error = bus_add_device(dev)))
 		goto BusError;
 	down_write(&devices_subsys.rwsem);
 	if (parent)
 		list_add_tail(&dev->node, &parent->children);
 	up_write(&devices_subsys.rwsem);

 	/* notify platform of device entry */
 	if (platform_notify)
 		platform_notify(dev);
  Done:
 	put_device(dev);
 	return error;
  BusError:
 	device_pm_remove(dev);
  PMError:
 	kobject_hotplug(&dev->kobj, KOBJ_REMOVE);
 	kobject_del(&dev->kobj);
  Error:
 	if (parent)
 		put_device(parent);
 	goto Done;
 }


 /**
  *	device_register - register a device with the system.
  *	@dev:	pointer to the device structure
  *
  *	This happens in two clean steps - initialize the device
  *	and add it to the system. The two steps can be called
  *	separately, but this is the easiest and most common.
  *	I.e. you should only call the two helpers separately if
  *	have a clearly defined need to use and refcount the device
  *	before it is added to the hierarchy.
  */

 int device_register(struct device *dev)
 {
 	device_initialize(dev);
 	return device_add(dev);
 }


 /**
  *	get_device - increment reference count for device.
  *	@dev:	device.
  *
  *	This simply forwards the call to kobject_get(), though
  *	we do take care to provide for the case that we get a NULL
  *	pointer passed in.
  */

 struct device * get_device(struct device * dev)
 {
 	return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
 }


 /**
  *	put_device - decrement reference count.
  *	@dev:	device in question.
  */
 void put_device(struct device * dev)
 {
 	if (dev)
 		kobject_put(&dev->kobj);
 }


 /**
  *	device_del - delete device from system.
  *	@dev:	device.
  *
  *	This is the first part of the device unregistration
  *	sequence. This removes the device from the lists we control
  *	from here, has it removed from the other driver model
  *	subsystems it was added to in device_add(), and removes it
  *	from the kobject hierarchy.
  *
  *	NOTE: this should be called manually _iff_ device_add() was
  *	also called manually.
  */

 void device_del(struct device * dev)
 {
 	struct device * parent = dev->parent;

 	down_write(&devices_subsys.rwsem);
 	if (parent)
 		list_del_init(&dev->node);
 	up_write(&devices_subsys.rwsem);

 	/* Notify the platform of the removal, in case they
 	 * need to do anything...
 	 */
 	if (platform_notify_remove)
 		platform_notify_remove(dev);
 	bus_remove_device(dev);
 	device_pm_remove(dev);
 	kobject_hotplug(&dev->kobj, KOBJ_REMOVE);
 	kobject_del(&dev->kobj);
 	if (parent)
 		put_device(parent);
 }

 /**
  *	device_unregister - unregister device from system.
  *	@dev:	device going away.
  *
  *	We do this in two parts, like we do device_register(). First,
  *	we remove it from all the subsystems with device_del(), then
  *	we decrement the reference count via put_device(). If that
  *	is the final reference count, the device will be cleaned up
  *	via device_release() above. Otherwise, the structure will
  *	stick around until the final reference to the device is dropped.
  */
 void device_unregister(struct device * dev)
 {
 	pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);
 	device_del(dev);
 	put_device(dev);
 }


 /**
  *	device_for_each_child - device child iterator.
  *	@dev:	parent struct device.
  *	@data:	data for the callback.
  *	@fn:	function to be called for each device.
  *
  *	Iterate over @dev's child devices, and call @fn for each,
  *	passing it @data.
  *
  *	We check the return of @fn each time. If it returns anything
  *	other than 0, we break out and return that value.
  */
 int device_for_each_child(struct device * dev, void * data,
 		     int (*fn)(struct device *, void *))
 {
 	struct device * child;
 	int error = 0;

 	down_read(&devices_subsys.rwsem);
 	list_for_each_entry(child, &dev->children, node) {
 		if((error = fn(child, data)))
 			break;
 	}
 	up_read(&devices_subsys.rwsem);
 	return error;
 }

 /**
  *	device_find - locate device on a bus by name.
  *	@name:	name of the device.
  *	@bus:	bus to scan for the device.
  *
  *	Call kset_find_obj() to iterate over list of devices on
  *	a bus to find device by name. Return device if found.
  *
  *	Note that kset_find_obj increments device's reference count.
  */
 struct device *device_find(const char *name, struct bus_type *bus)
 {
 	struct kobject *k = kset_find_obj(&bus->devices, name);
 	if (k)
 		return to_dev(k);
 	return NULL;
 }

 int __init devices_init(void)
 {
 	return subsystem_register(&devices_subsys);
 }

 EXPORT_SYMBOL_GPL(device_for_each_child);

 EXPORT_SYMBOL_GPL(device_initialize);
 EXPORT_SYMBOL_GPL(device_add);
 EXPORT_SYMBOL_GPL(device_register);

 EXPORT_SYMBOL_GPL(device_del);
 EXPORT_SYMBOL_GPL(device_unregister);
 EXPORT_SYMBOL_GPL(get_device);
 EXPORT_SYMBOL_GPL(put_device);
 EXPORT_SYMBOL_GPL(device_find);

 EXPORT_SYMBOL_GPL(device_create_file);
 EXPORT_SYMBOL_GPL(device_remove_file);
	/*
	* drivers/base/core.c - core driver model code (device registration, etc)
	*
	* Copyright (c) 2002-3 Patrick Mochel
	* Copyright (c) 2002-3 Open Source Development Labs
	*
	* This file is released under the GPLv2
	*
	*/

	#include <linux/config.h>
	#include <linux/device.h>
	#include <linux/err.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/string.h>

	#include <asm/semaphore.h>

	#include "base.h"
	#include "power/power.h"

	int (platform_notify)(struct device dev) = NULL;
	int (platform_notify_remove)(struct device dev) = NULL;

	/*
	* sysfs bindings for devices.
	*/

	#define to_dev(obj) container_of(obj, struct device, kobj)
	#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)

	static ssize_t
	dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
	{
	struct device_attribute * dev_attr = to_dev_attr(attr);
	struct device * dev = to_dev(kobj);
	ssize_t ret = -EIO;

	if (dev_attr->show)
	ret = dev_attr->show(dev, buf);
	return ret;
	}

	static ssize_t
	dev_attr_store(struct kobject * kobj, struct attribute * attr,
	const char * buf, size_t count)
	{
	struct device_attribute * dev_attr = to_dev_attr(attr);
	struct device * dev = to_dev(kobj);
	ssize_t ret = -EIO;

	if (dev_attr->store)
	ret = dev_attr->store(dev, buf, count);
	return ret;
	}

	static struct sysfs_ops dev_sysfs_ops = {
	.show = dev_attr_show,
	.store = dev_attr_store,
	};


	/**
	* device_release - free device structure.
	* @kobj: device's kobject.
	*
	* This is called once the reference count for the object
	* reaches 0. We forward the call to the device's release
	* method, which should handle actually freeing the structure.
	*/
	static void device_release(struct kobject * kobj)
	{
	struct device * dev = to_dev(kobj);

	if (dev->release)
	dev->release(dev);
	else {
	printk(KERN_ERR "Device '%s' does not have a release() function, "
	"it is broken and must be fixed.\n",
	dev->bus_id);
	WARN_ON(1);
	}
	}

	static struct kobj_type ktype_device = {
	.release = device_release,
	.sysfs_ops = &dev_sysfs_ops,
	};


	static int dev_hotplug_filter(struct kset kset, struct kobject kobj)
	{
	struct kobj_type *ktype = get_ktype(kobj);

	if (ktype == &ktype_device) {
	struct device *dev = to_dev(kobj);
	if (dev->bus)
	return 1;
	}
	return 0;
	}

	static const char dev_hotplug_name(struct kset kset, struct kobject *kobj)
	{
	struct device *dev = to_dev(kobj);

	return dev->bus->name;
	}

	static int dev_hotplug(struct kset kset, struct kobject kobj, char **envp,
	int num_envp, char *buffer, int buffer_size)
	{
	struct device *dev = to_dev(kobj);
	int i = 0;
	int length = 0;
	int retval = 0;

	/* add bus name of physical device */
	if (dev->bus)
	add_hotplug_env_var(envp, num_envp, &i,
	buffer, buffer_size, &length,
	"PHYSDEVBUS=%s", dev->bus->name);

	/* add driver name of physical device */
	if (dev->driver)
	add_hotplug_env_var(envp, num_envp, &i,
	buffer, buffer_size, &length,
	"PHYSDEVDRIVER=%s", dev->driver->name);

	/* terminate, set to next free slot, shrink available space */
	envp[i] = NULL;
	envp = &envp[i];
	num_envp -= i;
	buffer = &buffer[length];
	buffer_size -= length;

	if (dev->bus && dev->bus->hotplug) {
	/* have the bus specific function add its stuff */
	retval = dev->bus->hotplug (dev, envp, num_envp, buffer, buffer_size);
	if (retval) {
	pr_debug ("%s - hotplug() returned %d\n",
	__FUNCTION__, retval);
	}
	}

	return retval;
	}

	static struct kset_hotplug_ops device_hotplug_ops = {
	.filter = dev_hotplug_filter,
	.name = dev_hotplug_name,
	.hotplug = dev_hotplug,
	};

	/**
	* device_subsys - structure to be registered with kobject core.
	*/

	decl_subsys(devices, &ktype_device, &device_hotplug_ops);


	/**
	* device_create_file - create sysfs attribute file for device.
	* @dev: device.
	* @attr: device attribute descriptor.
	*/

	int device_create_file(struct device * dev, struct device_attribute * attr)
	{
	int error = 0;
	if (get_device(dev)) {
	error = sysfs_create_file(&dev->kobj, &attr->attr);
	put_device(dev);
	}
	return error;
	}

	/**
	* device_remove_file - remove sysfs attribute file.
	* @dev: device.
	* @attr: device attribute descriptor.
	*/

	void device_remove_file(struct device * dev, struct device_attribute * attr)
	{
	if (get_device(dev)) {
	sysfs_remove_file(&dev->kobj, &attr->attr);
	put_device(dev);
	}
	}


	/**
	* device_initialize - init device structure.
	* @dev: device.
	*
	* This prepares the device for use by other layers,
	* including adding it to the device hierarchy.
	* It is the first half of device_register(), if called by
	* that, though it can also be called separately, so one
	* may use @dev's fields (e.g. the refcount).
	*/

	void device_initialize(struct device *dev)
	{
	kobj_set_kset_s(dev, devices_subsys);
	kobject_init(&dev->kobj);
	INIT_LIST_HEAD(&dev->node);
	INIT_LIST_HEAD(&dev->children);
	INIT_LIST_HEAD(&dev->driver_list);
	INIT_LIST_HEAD(&dev->bus_list);
	INIT_LIST_HEAD(&dev->dma_pools);
	}

	/**
	* device_add - add device to device hierarchy.
	* @dev: device.
	*
	* This is part 2 of device_register(), though may be called
	* separately _iff_ device_initialize() has been called separately.
	*
	* This adds it to the kobject hierarchy via kobject_add(), adds it
	* to the global and sibling lists for the device, then
	* adds it to the other relevant subsystems of the driver model.
	*/
	int device_add(struct device *dev)
	{
	struct device *parent = NULL;
	int error = -EINVAL;

	dev = get_device(dev);
	if (!dev \|\| !strlen(dev->bus_id))
	goto Error;

	parent = get_device(dev->parent);

	pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);

	/* first, register with generic layer. */
	kobject_set_name(&dev->kobj, "%s", dev->bus_id);
	if (parent)
	dev->kobj.parent = &parent->kobj;

	if ((error = kobject_add(&dev->kobj)))
	goto Error;
	kobject_hotplug(&dev->kobj, KOBJ_ADD);
	if ((error = device_pm_add(dev)))
	goto PMError;
	if ((error = bus_add_device(dev)))
	goto BusError;
	down_write(&devices_subsys.rwsem);
	if (parent)
	list_add_tail(&dev->node, &parent->children);
	up_write(&devices_subsys.rwsem);

	/* notify platform of device entry */
	if (platform_notify)
	platform_notify(dev);
	Done:
	put_device(dev);
	return error;
	BusError:
	device_pm_remove(dev);
	PMError:
	kobject_hotplug(&dev->kobj, KOBJ_REMOVE);
	kobject_del(&dev->kobj);
	Error:
	if (parent)
	put_device(parent);
	goto Done;
	}


	/**
	* device_register - register a device with the system.
	* @dev: pointer to the device structure
	*
	* This happens in two clean steps - initialize the device
	* and add it to the system. The two steps can be called
	* separately, but this is the easiest and most common.
	* I.e. you should only call the two helpers separately if
	* have a clearly defined need to use and refcount the device
	* before it is added to the hierarchy.
	*/

	int device_register(struct device *dev)
	{
	device_initialize(dev);
	return device_add(dev);
	}


	/**
	* get_device - increment reference count for device.
	* @dev: device.
	*
	* This simply forwards the call to kobject_get(), though
	* we do take care to provide for the case that we get a NULL
	* pointer passed in.
	*/

	struct device * get_device(struct device * dev)
	{
	return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
	}


	/**
	* put_device - decrement reference count.
	* @dev: device in question.
	*/
	void put_device(struct device * dev)
	{
	if (dev)
	kobject_put(&dev->kobj);
	}


	/**
	* device_del - delete device from system.
	* @dev: device.
	*
	* This is the first part of the device unregistration
	* sequence. This removes the device from the lists we control
	* from here, has it removed from the other driver model
	* subsystems it was added to in device_add(), and removes it
	* from the kobject hierarchy.
	*
	* NOTE: this should be called manually _iff_ device_add() was
	* also called manually.
	*/

	void device_del(struct device * dev)
	{
	struct device * parent = dev->parent;

	down_write(&devices_subsys.rwsem);
	if (parent)
	list_del_init(&dev->node);
	up_write(&devices_subsys.rwsem);

	/* Notify the platform of the removal, in case they
	* need to do anything...
	*/
	if (platform_notify_remove)
	platform_notify_remove(dev);
	bus_remove_device(dev);
	device_pm_remove(dev);
	kobject_hotplug(&dev->kobj, KOBJ_REMOVE);
	kobject_del(&dev->kobj);
	if (parent)
	put_device(parent);
	}

	/**
	* device_unregister - unregister device from system.
	* @dev: device going away.
	*
	* We do this in two parts, like we do device_register(). First,
	* we remove it from all the subsystems with device_del(), then
	* we decrement the reference count via put_device(). If that
	* is the final reference count, the device will be cleaned up
	* via device_release() above. Otherwise, the structure will
	* stick around until the final reference to the device is dropped.
	*/
	void device_unregister(struct device * dev)
	{
	pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);
	device_del(dev);
	put_device(dev);
	}


	/**
	* device_for_each_child - device child iterator.
	* @dev: parent struct device.
	* @data: data for the callback.
	* @fn: function to be called for each device.
	*
	* Iterate over @dev's child devices, and call @fn for each,
	* passing it @data.
	*
	* We check the return of @fn each time. If it returns anything
	* other than 0, we break out and return that value.
	*/
	int device_for_each_child(struct device * dev, void * data,
	int (fn)(struct device , void *))
	{
	struct device * child;
	int error = 0;

	down_read(&devices_subsys.rwsem);
	list_for_each_entry(child, &dev->children, node) {
	if((error = fn(child, data)))
	break;
	}
	up_read(&devices_subsys.rwsem);
	return error;
	}

	/**
	* device_find - locate device on a bus by name.
	* @name: name of the device.
	* @bus: bus to scan for the device.
	*
	* Call kset_find_obj() to iterate over list of devices on
	* a bus to find device by name. Return device if found.
	*
	* Note that kset_find_obj increments device's reference count.
	*/
	struct device device_find(const char name, struct bus_type *bus)
	{
	struct kobject *k = kset_find_obj(&bus->devices, name);
	if (k)
	return to_dev(k);
	return NULL;
	}

	int __init devices_init(void)
	{
	return subsystem_register(&devices_subsys);
	}

	EXPORT_SYMBOL_GPL(device_for_each_child);

	EXPORT_SYMBOL_GPL(device_initialize);
	EXPORT_SYMBOL_GPL(device_add);
	EXPORT_SYMBOL_GPL(device_register);

	EXPORT_SYMBOL_GPL(device_del);
	EXPORT_SYMBOL_GPL(device_unregister);
	EXPORT_SYMBOL_GPL(get_device);
	EXPORT_SYMBOL_GPL(put_device);
	EXPORT_SYMBOL_GPL(device_find);

	EXPORT_SYMBOL_GPL(device_create_file);
	EXPORT_SYMBOL_GPL(device_remove_file);