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(objp: dev);
35}
36
37static const 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(class: &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(dev: 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(kobj: &iommu->dev->kobj, fmt, vargs);
74 va_end(vargs);
75 if (ret)
76 goto error;
77
78 ret = device_add(dev: iommu->dev);
79 if (ret)
80 goto error;
81
82 dev_set_drvdata(dev: iommu->dev, data: iommu);
83
84 return 0;
85
86error:
87 put_device(dev: 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(dev: iommu->dev, NULL);
95 device_unregister(dev: 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(kobj: &iommu->dev->kobj, group_name: "devices",
111 target: &link->kobj, link_name: dev_name(dev: link));
112 if (ret)
113 return ret;
114
115 ret = sysfs_create_link_nowarn(kobj: &link->kobj, target: &iommu->dev->kobj, name: "iommu");
116 if (ret)
117 sysfs_remove_link_from_group(kobj: &iommu->dev->kobj, group_name: "devices",
118 link_name: dev_name(dev: link));
119
120 return ret;
121}
122
123void iommu_device_unlink(struct iommu_device *iommu, struct device *link)
124{
125 sysfs_remove_link(kobj: &link->kobj, name: "iommu");
126 sysfs_remove_link_from_group(kobj: &iommu->dev->kobj, group_name: "devices", link_name: dev_name(dev: link));
127}
128