Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 279 insertions, 0 deletions

diff --git a/drivers/base/transport_class.c b/drivers/base/transport_class.c
new file mode 100644
index 000000000..5ed86ded6
--- /dev/null
+++ b/drivers/base/transport_class.c
@@ -0,0 +1,279 @@
+// 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);