// 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> static int transport_remove_classdev(struct attribute_container *cont,				     struct device *dev,				     struct device *classdev); /** * 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. */void anon_transport_class_register(struct anon_transport_class *atc){	atc->container.class = &atc->tclass.class;	attribute_container_set_no_classdevs(&atc->container);	attribute_container_register(&atc->container);	atc->tclass.setup = anon_transport_dummy_function;	atc->tclass.remove = anon_transport_dummy_function;}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){	struct transport_class *tclass = class_to_transport_class(cont->class);	int error = attribute_container_add_class_device(classdev);	struct transport_container *tcont = 		attribute_container_to_transport_container(cont); 	if (error)		goto err_remove; 	if (tcont->statistics) {		error = sysfs_create_group(&classdev->kobj, tcont->statistics);		if (error)			goto err_del;	} 	if (tcont->encryption) {		error = sysfs_create_group(&classdev->kobj, tcont->encryption);		if (error)			goto err_del_statistics;	} 	return 0; err_del_statistics:	if (tcont->statistics)		sysfs_remove_group(&classdev->kobj, tcont->statistics);err_del:	attribute_container_class_device_del(classdev);err_remove:	if (tclass->remove)		tclass->remove(tcont, dev, classdev); 	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. */int transport_add_device(struct device *dev){	return attribute_container_device_trigger_safe(dev,					transport_add_class_device,					transport_remove_classdev);}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);		if (tcont->encryption)			sysfs_remove_group(&classdev->kobj, tcont->encryption);		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);