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// SPDX-License-Identifier: GPL-2.0-only
/*
* IOMMU sysfs class support
*
* Copyright (C) 2014 Red Hat, Inc. All rights reserved.
* Author: Alex Williamson <alex.williamson@redhat.com>
*/
#include <linux/device.h>
#include <linux/iommu.h>
#include <linux/init.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 devices_attr_group = {
.name = "devices",
.attrs = devices_attr,
};
static const struct attribute_group *dev_groups[] = {
&devices_attr_group,
NULL,
};
static void release_device(struct device *dev)
{
kfree(dev);
}
static struct class iommu_class = {
.name = "iommu",
.dev_release = release_device,
.dev_groups = dev_groups,
};
static int __init iommu_dev_init(void)
{
return class_register(&iommu_class);
}
postcore_initcall(iommu_dev_init);
/*
* Init the struct device for the IOMMU. IOMMU specific attributes can
* be provided as an attribute group, allowing a unique namespace per
* IOMMU type.
*/
int iommu_device_sysfs_add(struct iommu_device *iommu,
struct device *parent,
const struct attribute_group **groups,
const char *fmt, ...)
{
va_list vargs;
int ret;
iommu->dev = kzalloc(sizeof(*iommu->dev), GFP_KERNEL);
if (!iommu->dev)
return -ENOMEM;
device_initialize(iommu->dev);
iommu->dev->class = &iommu_class;
iommu->dev->parent = parent;
iommu->dev->groups = groups;
va_start(vargs, fmt);
ret = kobject_set_name_vargs(&iommu->dev->kobj, fmt, vargs);
va_end(vargs);
if (ret)
goto error;
ret = device_add(iommu->dev);
if (ret)
goto error;
dev_set_drvdata(iommu->dev, iommu);
return 0;
error:
put_device(iommu->dev);
return ret;
}
void iommu_device_sysfs_remove(struct iommu_device *iommu)
{
dev_set_drvdata(iommu->dev, NULL);
device_unregister(iommu->dev);
iommu->dev = NULL;
}
/*
* 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 iommu_device *iommu, struct device *link)
{
int ret;
if (!iommu || IS_ERR(iommu))
return -ENODEV;
ret = sysfs_add_link_to_group(&iommu->dev->kobj, "devices",
&link->kobj, dev_name(link));
if (ret)
return ret;
ret = sysfs_create_link_nowarn(&link->kobj, &iommu->dev->kobj, "iommu");
if (ret)
sysfs_remove_link_from_group(&iommu->dev->kobj, "devices",
dev_name(link));
return ret;
}
void iommu_device_unlink(struct iommu_device *iommu, struct device *link)
{
if (!iommu || IS_ERR(iommu))
return;
sysfs_remove_link(&link->kobj, "iommu");
sysfs_remove_link_from_group(&iommu->dev->kobj, "devices", dev_name(link));
}
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