transport_class.c

Go to the documentation of this file.

/*
 * transport_class.c - implementation of generic transport classes
 *                     using attribute_containers
 *
 * Copyright (c) 2005 - James Bottomley <[email protected]>
 *
 * 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/export.h>
#include <linux/attribute_container.h>
#include <linux/transport_class.h>

int transport_class_register(struct transport_class *tclass)
{
    return class_register(&tclass->class);
}
EXPORT_SYMBOL_GPL(transport_class_register);

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;
}

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);

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;
}

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;
}


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;
}

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;
}


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);
}


void transport_destroy_device(struct device *dev)
{
    attribute_container_remove_device(dev, transport_destroy_classdev);
}
EXPORT_SYMBOL_GPL(transport_destroy_device);