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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/base/transport_class.c
downloadkernel-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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diff --git a/drivers/base/transport_class.c b/drivers/base/transport_class.c
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+/*
+ * transport_class.c - implementation of generic transport classes
+ * using attribute_containers
+ *
+ * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
+ *
+ * This file is licensed under GPLv2
+ *
+ * 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/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 device *dev)
+{
+ /* 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)
+{
+ attribute_container_unregister(&atc->container);
+}
+EXPORT_SYMBOL_GPL(anon_transport_class_unregister);
+
+static int transport_setup_classdev(struct attribute_container *cont,
+ struct device *dev,
+ struct class_device *classdev)
+{
+ struct transport_class *tclass = class_to_transport_class(cont->class);
+
+ if (tclass->setup)
+ tclass->setup(dev);
+
+ 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 class_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 transport_class *tclass = class_to_transport_class(cont->class);
+
+ if (tclass->configure)
+ tclass->configure(dev);
+
+ 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_trigger(dev, transport_configure);
+}
+EXPORT_SYMBOL_GPL(transport_configure_device);
+
+static int transport_remove_classdev(struct attribute_container *cont,
+ struct device *dev,
+ struct class_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(dev);
+
+ 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 class_device *classdev)
+{
+ struct transport_class *tclass = class_to_transport_class(cont->class);
+
+ if (tclass->remove != anon_transport_dummy_function)
+ class_device_put(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);