1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * IOMMU sysfs class support
4 *
5 * Copyright (C) 2014 Red Hat, Inc.  All rights reserved.
6 *     Author: Alex Williamson <alex.williamson@redhat.com>
7 */
8
9#include <linux/device.h>
10#include <linux/iommu.h>
11#include <linux/init.h>
12#include <linux/slab.h>
13
14/*
15 * We provide a common class "devices" group which initially has no attributes.
16 * As devices are added to the IOMMU, we'll add links to the group.
17 */
18static struct attribute *devices_attr[] = {
19	NULL,
20};
21
22static const struct attribute_group devices_attr_group = {
23	.name = "devices",
24	.attrs = devices_attr,
25};
26
27static const struct attribute_group *dev_groups[] = {
28	&devices_attr_group,
29	NULL,
30};
31
32static void release_device(struct device *dev)
33{
34	kfree(dev);
35}
36
37static struct class iommu_class = {
38	.name = "iommu",
39	.dev_release = release_device,
40	.dev_groups = dev_groups,
41};
42
43static int __init iommu_dev_init(void)
44{
45	return class_register(&iommu_class);
46}
47postcore_initcall(iommu_dev_init);
48
49/*
50 * Init the struct device for the IOMMU. IOMMU specific attributes can
51 * be provided as an attribute group, allowing a unique namespace per
52 * IOMMU type.
53 */
54int iommu_device_sysfs_add(struct iommu_device *iommu,
55			   struct device *parent,
56			   const struct attribute_group **groups,
57			   const char *fmt, ...)
58{
59	va_list vargs;
60	int ret;
61
62	iommu->dev = kzalloc(sizeof(*iommu->dev), GFP_KERNEL);
63	if (!iommu->dev)
64		return -ENOMEM;
65
66	device_initialize(iommu->dev);
67
68	iommu->dev->class = &iommu_class;
69	iommu->dev->parent = parent;
70	iommu->dev->groups = groups;
71
72	va_start(vargs, fmt);
73	ret = kobject_set_name_vargs(&iommu->dev->kobj, fmt, vargs);
74	va_end(vargs);
75	if (ret)
76		goto error;
77
78	ret = device_add(iommu->dev);
79	if (ret)
80		goto error;
81
82	dev_set_drvdata(iommu->dev, iommu);
83
84	return 0;
85
86error:
87	put_device(iommu->dev);
88	return ret;
89}
90EXPORT_SYMBOL_GPL(iommu_device_sysfs_add);
91
92void iommu_device_sysfs_remove(struct iommu_device *iommu)
93{
94	dev_set_drvdata(iommu->dev, NULL);
95	device_unregister(iommu->dev);
96	iommu->dev = NULL;
97}
98EXPORT_SYMBOL_GPL(iommu_device_sysfs_remove);
99
100/*
101 * IOMMU drivers can indicate a device is managed by a given IOMMU using
102 * this interface.  A link to the device will be created in the "devices"
103 * directory of the IOMMU device in sysfs and an "iommu" link will be
104 * created under the linked device, pointing back at the IOMMU device.
105 */
106int iommu_device_link(struct iommu_device *iommu, struct device *link)
107{
108	int ret;
109
110	ret = sysfs_add_link_to_group(&iommu->dev->kobj, "devices",
111				      &link->kobj, dev_name(link));
112	if (ret)
113		return ret;
114
115	ret = sysfs_create_link_nowarn(&link->kobj, &iommu->dev->kobj, "iommu");
116	if (ret)
117		sysfs_remove_link_from_group(&iommu->dev->kobj, "devices",
118					     dev_name(link));
119
120	return ret;
121}
122
123void iommu_device_unlink(struct iommu_device *iommu, struct device *link)
124{
125	sysfs_remove_link(&link->kobj, "iommu");
126	sysfs_remove_link_from_group(&iommu->dev->kobj, "devices", dev_name(link));
127}
128