drivers/base/transport_class.c - linux-mtk - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * transport_class.c - implementation of generic transport classes
  *                     using attribute_containers
  *
  * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
  *
  * The basic idea here is to allow any "device controller" (which
  * would most often be a Host Bus Adapter to use the services of one
  * or more tranport classes for performing transport specific
  * services.  Transport specific services are things that the generic
  * command layer doesn't want to know about (speed settings, line
  * condidtioning, etc), but which the user might be interested in.
  * Thus, the HBA's use the routines exported by the transport classes
  * to perform these functions.  The transport classes export certain
  * values to the user via sysfs using attribute containers.
  *
  * Note: because not every HBA will care about every transport
  * attribute, there's a many to one relationship that goes like this:
  *
  * transport class<-----attribute container<----class device
  *
  * Usually the attribute container is per-HBA, but the design doesn't
  * mandate that.  Although most of the services will be specific to
  * the actual external storage connection used by the HBA, the generic
  * transport class is framed entirely in terms of generic devices to
  * allow it to be used by any physical HBA in the system.
  */
 #include <linux/export.h>
 #include <linux/attribute_container.h>
 #include <linux/transport_class.h>

 /**
  * transport_class_register - register an initial transport class
  *
  * @tclass:	a pointer to the transport class structure to be initialised
  *
  * The transport class contains an embedded class which is used to
  * identify it.  The caller should initialise this structure with
  * zeros and then generic class must have been initialised with the
  * actual transport class unique name.  There's a macro
  * DECLARE_TRANSPORT_CLASS() to do this (declared classes still must
  * be registered).
  *
  * Returns 0 on success or error on failure.
  */
 int transport_class_register(struct transport_class *tclass)
 {
 	return class_register(&tclass->class);
 }
 EXPORT_SYMBOL_GPL(transport_class_register);

 /**
  * transport_class_unregister - unregister a previously registered class
  *
  * @tclass: The transport class to unregister
  *
  * Must be called prior to deallocating the memory for the transport
  * class.
  */
 void transport_class_unregister(struct transport_class *tclass)
 {
 	class_unregister(&tclass->class);
 }
 EXPORT_SYMBOL_GPL(transport_class_unregister);

 static int anon_transport_dummy_function(struct transport_container *tc,
 					 struct device *dev,
 					 struct device *cdev)
 {
 	/* do nothing */
 	return 0;
 }

 /**
  * anon_transport_class_register - register an anonymous class
  *
  * @atc: The anon transport class to register
  *
  * The anonymous transport class contains both a transport class and a
  * container.  The idea of an anonymous class is that it never
  * actually has any device attributes associated with it (and thus
  * saves on container storage).  So it can only be used for triggering
  * events.  Use prezero and then use DECLARE_ANON_TRANSPORT_CLASS() to
  * initialise the anon transport class storage.
  */
 int anon_transport_class_register(struct anon_transport_class *atc)
 {
 	int error;
 	atc->container.class = &atc->tclass.class;
 	attribute_container_set_no_classdevs(&atc->container);
 	error = attribute_container_register(&atc->container);
 	if (error)
 		return error;
 	atc->tclass.setup = anon_transport_dummy_function;
 	atc->tclass.remove = anon_transport_dummy_function;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(anon_transport_class_register);

 /**
  * anon_transport_class_unregister - unregister an anon class
  *
  * @atc: Pointer to the anon transport class to unregister
  *
  * Must be called prior to deallocating the memory for the anon
  * transport class.
  */
 void anon_transport_class_unregister(struct anon_transport_class *atc)
 {
 	if (unlikely(attribute_container_unregister(&atc->container)))
 		BUG();
 }
 EXPORT_SYMBOL_GPL(anon_transport_class_unregister);

 static int transport_setup_classdev(struct attribute_container *cont,
 				    struct device *dev,
 				    struct device *classdev)
 {
 	struct transport_class *tclass = class_to_transport_class(cont->class);
 	struct transport_container *tcont = attribute_container_to_transport_container(cont);

 	if (tclass->setup)
 		tclass->setup(tcont, dev, classdev);

 	return 0;
 }

 /**
  * transport_setup_device - declare a new dev for transport class association but don't make it visible yet.
  * @dev: the generic device representing the entity being added
  *
  * Usually, dev represents some component in the HBA system (either
  * the HBA itself or a device remote across the HBA bus).  This
  * routine is simply a trigger point to see if any set of transport
  * classes wishes to associate with the added device.  This allocates
  * storage for the class device and initialises it, but does not yet
  * add it to the system or add attributes to it (you do this with
  * transport_add_device).  If you have no need for a separate setup
  * and add operations, use transport_register_device (see
  * transport_class.h).
  */

 void transport_setup_device(struct device *dev)
 {
 	attribute_container_add_device(dev, transport_setup_classdev);
 }
 EXPORT_SYMBOL_GPL(transport_setup_device);

 static int transport_add_class_device(struct attribute_container *cont,
 				      struct device *dev,
 				      struct device *classdev)
 {
 	int error = attribute_container_add_class_device(classdev);
 	struct transport_container *tcont =
 		attribute_container_to_transport_container(cont);

 	if (!error && tcont->statistics)
 		error = sysfs_create_group(&classdev->kobj, tcont->statistics);

 	return error;
 }


 /**
  * transport_add_device - declare a new dev for transport class association
  *
  * @dev: the generic device representing the entity being added
  *
  * Usually, dev represents some component in the HBA system (either
  * the HBA itself or a device remote across the HBA bus).  This
  * routine is simply a trigger point used to add the device to the
  * system and register attributes for it.
  */

 void transport_add_device(struct device *dev)
 {
 	attribute_container_device_trigger(dev, transport_add_class_device);
 }
 EXPORT_SYMBOL_GPL(transport_add_device);

 static int transport_configure(struct attribute_container *cont,
 			       struct device *dev,
 			       struct device *cdev)
 {
 	struct transport_class *tclass = class_to_transport_class(cont->class);
 	struct transport_container *tcont = attribute_container_to_transport_container(cont);

 	if (tclass->configure)
 		tclass->configure(tcont, dev, cdev);

 	return 0;
 }

 /**
  * transport_configure_device - configure an already set up device
  *
  * @dev: generic device representing device to be configured
  *
  * The idea of configure is simply to provide a point within the setup
  * process to allow the transport class to extract information from a
  * device after it has been setup.  This is used in SCSI because we
  * have to have a setup device to begin using the HBA, but after we
  * send the initial inquiry, we use configure to extract the device
  * parameters.  The device need not have been added to be configured.
  */
 void transport_configure_device(struct device *dev)
 {
 	attribute_container_device_trigger(dev, transport_configure);
 }
 EXPORT_SYMBOL_GPL(transport_configure_device);

 static int transport_remove_classdev(struct attribute_container *cont,
 				     struct device *dev,
 				     struct device *classdev)
 {
 	struct transport_container *tcont =
 		attribute_container_to_transport_container(cont);
 	struct transport_class *tclass = class_to_transport_class(cont->class);

 	if (tclass->remove)
 		tclass->remove(tcont, dev, classdev);

 	if (tclass->remove != anon_transport_dummy_function) {
 		if (tcont->statistics)
 			sysfs_remove_group(&classdev->kobj, tcont->statistics);
 		attribute_container_class_device_del(classdev);
 	}

 	return 0;
 }


 /**
  * transport_remove_device - remove the visibility of a device
  *
  * @dev: generic device to remove
  *
  * This call removes the visibility of the device (to the user from
  * sysfs), but does not destroy it.  To eliminate a device entirely
  * you must also call transport_destroy_device.  If you don't need to
  * do remove and destroy as separate operations, use
  * transport_unregister_device() (see transport_class.h) which will
  * perform both calls for you.
  */
 void transport_remove_device(struct device *dev)
 {
 	attribute_container_device_trigger(dev, transport_remove_classdev);
 }
 EXPORT_SYMBOL_GPL(transport_remove_device);

 static void transport_destroy_classdev(struct attribute_container *cont,
 				      struct device *dev,
 				      struct device *classdev)
 {
 	struct transport_class *tclass = class_to_transport_class(cont->class);

 	if (tclass->remove != anon_transport_dummy_function)
 		put_device(classdev);
 }


 /**
  * transport_destroy_device - destroy a removed device
  *
  * @dev: device to eliminate from the transport class.
  *
  * This call triggers the elimination of storage associated with the
  * transport classdev.  Note: all it really does is relinquish a
  * reference to the classdev.  The memory will not be freed until the
  * last reference goes to zero.  Note also that the classdev retains a
  * reference count on dev, so dev too will remain for as long as the
  * transport class device remains around.
  */
 void transport_destroy_device(struct device *dev)
 {
 	attribute_container_remove_device(dev, transport_destroy_classdev);
 }
 EXPORT_SYMBOL_GPL(transport_destroy_device);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* transport_class.c - implementation of generic transport classes
	* using attribute_containers
	*
	* Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
	*
	* The basic idea here is to allow any "device controller" (which
	* would most often be a Host Bus Adapter to use the services of one
	* or more tranport classes for performing transport specific
	* services. Transport specific services are things that the generic
	* command layer doesn't want to know about (speed settings, line
	* condidtioning, etc), but which the user might be interested in.
	* Thus, the HBA's use the routines exported by the transport classes
	* to perform these functions. The transport classes export certain
	* values to the user via sysfs using attribute containers.
	*
	* Note: because not every HBA will care about every transport
	* attribute, there's a many to one relationship that goes like this:
	*
	* transport class<-----attribute container<----class device
	*
	* Usually the attribute container is per-HBA, but the design doesn't
	* mandate that. Although most of the services will be specific to
	* the actual external storage connection used by the HBA, the generic
	* transport class is framed entirely in terms of generic devices to
	* allow it to be used by any physical HBA in the system.
	*/
	#include <linux/export.h>
	#include <linux/attribute_container.h>
	#include <linux/transport_class.h>

	/**
	* transport_class_register - register an initial transport class
	*
	* @tclass: a pointer to the transport class structure to be initialised
	*
	* The transport class contains an embedded class which is used to
	* identify it. The caller should initialise this structure with
	* zeros and then generic class must have been initialised with the
	* actual transport class unique name. There's a macro
	* DECLARE_TRANSPORT_CLASS() to do this (declared classes still must
	* be registered).
	*
	* Returns 0 on success or error on failure.
	*/
	int transport_class_register(struct transport_class *tclass)
	{
	return class_register(&tclass->class);
	}
	EXPORT_SYMBOL_GPL(transport_class_register);

	/**
	* transport_class_unregister - unregister a previously registered class
	*
	* @tclass: The transport class to unregister
	*
	* Must be called prior to deallocating the memory for the transport
	* class.
	*/
	void transport_class_unregister(struct transport_class *tclass)
	{
	class_unregister(&tclass->class);
	}
	EXPORT_SYMBOL_GPL(transport_class_unregister);

	static int anon_transport_dummy_function(struct transport_container *tc,
	struct device *dev,
	struct device *cdev)
	{
	/* do nothing */
	return 0;
	}

	/**
	* anon_transport_class_register - register an anonymous class
	*
	* @atc: The anon transport class to register
	*
	* The anonymous transport class contains both a transport class and a
	* container. The idea of an anonymous class is that it never
	* actually has any device attributes associated with it (and thus
	* saves on container storage). So it can only be used for triggering
	* events. Use prezero and then use DECLARE_ANON_TRANSPORT_CLASS() to
	* initialise the anon transport class storage.
	*/
	int anon_transport_class_register(struct anon_transport_class *atc)
	{
	int error;
	atc->container.class = &atc->tclass.class;
	attribute_container_set_no_classdevs(&atc->container);
	error = attribute_container_register(&atc->container);
	if (error)
	return error;
	atc->tclass.setup = anon_transport_dummy_function;
	atc->tclass.remove = anon_transport_dummy_function;
	return 0;
	}
	EXPORT_SYMBOL_GPL(anon_transport_class_register);

	/**
	* anon_transport_class_unregister - unregister an anon class
	*
	* @atc: Pointer to the anon transport class to unregister
	*
	* Must be called prior to deallocating the memory for the anon
	* transport class.
	*/
	void anon_transport_class_unregister(struct anon_transport_class *atc)
	{
	if (unlikely(attribute_container_unregister(&atc->container)))
	BUG();
	}
	EXPORT_SYMBOL_GPL(anon_transport_class_unregister);

	static int transport_setup_classdev(struct attribute_container *cont,
	struct device *dev,
	struct device *classdev)
	{
	struct transport_class *tclass = class_to_transport_class(cont->class);
	struct transport_container *tcont = attribute_container_to_transport_container(cont);

	if (tclass->setup)
	tclass->setup(tcont, dev, classdev);

	return 0;
	}

	/**
	* transport_setup_device - declare a new dev for transport class association but don't make it visible yet.
	* @dev: the generic device representing the entity being added
	*
	* Usually, dev represents some component in the HBA system (either
	* the HBA itself or a device remote across the HBA bus). This
	* routine is simply a trigger point to see if any set of transport
	* classes wishes to associate with the added device. This allocates
	* storage for the class device and initialises it, but does not yet
	* add it to the system or add attributes to it (you do this with
	* transport_add_device). If you have no need for a separate setup
	* and add operations, use transport_register_device (see
	* transport_class.h).
	*/

	void transport_setup_device(struct device *dev)
	{
	attribute_container_add_device(dev, transport_setup_classdev);
	}
	EXPORT_SYMBOL_GPL(transport_setup_device);

	static int transport_add_class_device(struct attribute_container *cont,
	struct device *dev,
	struct device *classdev)
	{
	int error = attribute_container_add_class_device(classdev);
	struct transport_container *tcont =
	attribute_container_to_transport_container(cont);

	if (!error && tcont->statistics)
	error = sysfs_create_group(&classdev->kobj, tcont->statistics);

	return error;
	}


	/**
	* transport_add_device - declare a new dev for transport class association
	*
	* @dev: the generic device representing the entity being added
	*
	* Usually, dev represents some component in the HBA system (either
	* the HBA itself or a device remote across the HBA bus). This
	* routine is simply a trigger point used to add the device to the
	* system and register attributes for it.
	*/

	void transport_add_device(struct device *dev)
	{
	attribute_container_device_trigger(dev, transport_add_class_device);
	}
	EXPORT_SYMBOL_GPL(transport_add_device);

	static int transport_configure(struct attribute_container *cont,
	struct device *dev,
	struct device *cdev)
	{
	struct transport_class *tclass = class_to_transport_class(cont->class);
	struct transport_container *tcont = attribute_container_to_transport_container(cont);

	if (tclass->configure)
	tclass->configure(tcont, dev, cdev);

	return 0;
	}

	/**
	* transport_configure_device - configure an already set up device
	*
	* @dev: generic device representing device to be configured
	*
	* The idea of configure is simply to provide a point within the setup
	* process to allow the transport class to extract information from a
	* device after it has been setup. This is used in SCSI because we
	* have to have a setup device to begin using the HBA, but after we
	* send the initial inquiry, we use configure to extract the device
	* parameters. The device need not have been added to be configured.
	*/
	void transport_configure_device(struct device *dev)
	{
	attribute_container_device_trigger(dev, transport_configure);
	}
	EXPORT_SYMBOL_GPL(transport_configure_device);

	static int transport_remove_classdev(struct attribute_container *cont,
	struct device *dev,
	struct device *classdev)
	{
	struct transport_container *tcont =
	attribute_container_to_transport_container(cont);
	struct transport_class *tclass = class_to_transport_class(cont->class);

	if (tclass->remove)
	tclass->remove(tcont, dev, classdev);

	if (tclass->remove != anon_transport_dummy_function) {
	if (tcont->statistics)
	sysfs_remove_group(&classdev->kobj, tcont->statistics);
	attribute_container_class_device_del(classdev);
	}

	return 0;
	}


	/**
	* transport_remove_device - remove the visibility of a device
	*
	* @dev: generic device to remove
	*
	* This call removes the visibility of the device (to the user from
	* sysfs), but does not destroy it. To eliminate a device entirely
	* you must also call transport_destroy_device. If you don't need to
	* do remove and destroy as separate operations, use
	* transport_unregister_device() (see transport_class.h) which will
	* perform both calls for you.
	*/
	void transport_remove_device(struct device *dev)
	{
	attribute_container_device_trigger(dev, transport_remove_classdev);
	}
	EXPORT_SYMBOL_GPL(transport_remove_device);

	static void transport_destroy_classdev(struct attribute_container *cont,
	struct device *dev,
	struct device *classdev)
	{
	struct transport_class *tclass = class_to_transport_class(cont->class);

	if (tclass->remove != anon_transport_dummy_function)
	put_device(classdev);
	}


	/**
	* transport_destroy_device - destroy a removed device
	*
	* @dev: device to eliminate from the transport class.
	*
	* This call triggers the elimination of storage associated with the
	* transport classdev. Note: all it really does is relinquish a
	* reference to the classdev. The memory will not be freed until the
	* last reference goes to zero. Note also that the classdev retains a
	* reference count on dev, so dev too will remain for as long as the
	* transport class device remains around.
	*/
	void transport_destroy_device(struct device *dev)
	{
	attribute_container_remove_device(dev, transport_destroy_classdev);
	}
	EXPORT_SYMBOL_GPL(transport_destroy_device);