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/*
* IOMMU sysfs class support
*
* Copyright (C) 2014 Red Hat, Inc. All rights reserved.
* Author: Alex Williamson <alex.williamson@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/device.h>
#include <linux/iommu.h>
#include <linux/module.h>
#include <linux/slab.h>
/*
* We provide a common class "devices" group which initially has no attributes.
* As devices are added to the IOMMU, we'll add links to the group.
*/
static struct attribute *devices_attr[] = {
NULL,
};
static const struct attribute_group iommu_devices_attr_group = {
.name = "devices",
.attrs = devices_attr,
};
static const struct attribute_group *iommu_dev_groups[] = {
&iommu_devices_attr_group,
NULL,
};
static void iommu_release_device(struct device *dev)
{
kfree(dev);
}
static struct class iommu_class = {
.name = "iommu",
.dev_release = iommu_release_device,
.dev_groups = iommu_dev_groups,
};
static int __init iommu_dev_init(void)
{
return class_register(&iommu_class);
}
postcore_initcall(iommu_dev_init);
/*
* Create an IOMMU device and return a pointer to it. IOMMU specific
* attributes can be provided as an attribute group, allowing a unique
* namespace per IOMMU type.
*/
struct device *iommu_device_create(struct device *parent, void *drvdata,
const struct attribute_group **groups,
const char *fmt, ...)
{
struct device *dev;
va_list vargs;
int ret;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
return ERR_PTR(-ENOMEM);
device_initialize(dev);
dev->class = &iommu_class;
dev->parent = parent;
dev->groups = groups;
dev_set_drvdata(dev, drvdata);
va_start(vargs, fmt);
ret = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
va_end(vargs);
if (ret)
goto error;
ret = device_add(dev);
if (ret)
goto error;
return dev;
error:
put_device(dev);
return ERR_PTR(ret);
}
void iommu_device_destroy(struct device *dev)
{
if (!dev || IS_ERR(dev))
return;
device_unregister(dev);
}
/*
* IOMMU drivers can indicate a device is managed by a given IOMMU using
* this interface. A link to the device will be created in the "devices"
* directory of the IOMMU device in sysfs and an "iommu" link will be
* created under the linked device, pointing back at the IOMMU device.
*/
int iommu_device_link(struct device *dev, struct device *link)
{
int ret;
if (!dev || IS_ERR(dev))
return -ENODEV;
ret = sysfs_add_link_to_group(&dev->kobj, "devices",
&link->kobj, dev_name(link));
if (ret)
return ret;
ret = sysfs_create_link_nowarn(&link->kobj, &dev->kobj, "iommu");
if (ret)
sysfs_remove_link_from_group(&dev->kobj, "devices",
dev_name(link));
return ret;
}
void iommu_device_unlink(struct device *dev, struct device *link)
{
if (!dev || IS_ERR(dev))
return;
sysfs_remove_link(&link->kobj, "iommu");
sysfs_remove_link_from_group(&dev->kobj, "devices", dev_name(link));
}
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