tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * IOMMU sysfs class support
3 *
4 * Copyright (C) 2014 Red Hat, Inc. All rights reserved.
5 * Author: Alex Williamson <alex.williamson@redhat.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/device.h>
13#include <linux/iommu.h>
14#include <linux/init.h>
15#include <linux/slab.h>
16
17/*
18 * We provide a common class "devices" group which initially has no attributes.
19 * As devices are added to the IOMMU, we'll add links to the group.
20 */
21static struct attribute *devices_attr[] = {
22 NULL,
23};
24
25static const struct attribute_group devices_attr_group = {
26 .name = "devices",
27 .attrs = devices_attr,
28};
29
30static const struct attribute_group *dev_groups[] = {
31 &devices_attr_group,
32 NULL,
33};
34
35static void release_device(struct device *dev)
36{
37 kfree(dev);
38}
39
40static struct class iommu_class = {
41 .name = "iommu",
42 .dev_release = release_device,
43 .dev_groups = dev_groups,
44};
45
46static int __init iommu_dev_init(void)
47{
48 return class_register(&iommu_class);
49}
50postcore_initcall(iommu_dev_init);
51
52/*
53 * Init the struct device for the IOMMU. IOMMU specific attributes can
54 * be provided as an attribute group, allowing a unique namespace per
55 * IOMMU type.
56 */
57int iommu_device_sysfs_add(struct iommu_device *iommu,
58 struct device *parent,
59 const struct attribute_group **groups,
60 const char *fmt, ...)
61{
62 va_list vargs;
63 int ret;
64
65 iommu->dev = kzalloc(sizeof(*iommu->dev), GFP_KERNEL);
66 if (!iommu->dev)
67 return -ENOMEM;
68
69 device_initialize(iommu->dev);
70
71 iommu->dev->class = &iommu_class;
72 iommu->dev->parent = parent;
73 iommu->dev->groups = groups;
74
75 va_start(vargs, fmt);
76 ret = kobject_set_name_vargs(&iommu->dev->kobj, fmt, vargs);
77 va_end(vargs);
78 if (ret)
79 goto error;
80
81 ret = device_add(iommu->dev);
82 if (ret)
83 goto error;
84
85 dev_set_drvdata(iommu->dev, iommu);
86
87 return 0;
88
89error:
90 put_device(iommu->dev);
91 return ret;
92}
93
94void iommu_device_sysfs_remove(struct iommu_device *iommu)
95{
96 dev_set_drvdata(iommu->dev, NULL);
97 device_unregister(iommu->dev);
98 iommu->dev = NULL;
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 if (!iommu || IS_ERR(iommu))
111 return -ENODEV;
112
113 ret = sysfs_add_link_to_group(&iommu->dev->kobj, "devices",
114 &link->kobj, dev_name(link));
115 if (ret)
116 return ret;
117
118 ret = sysfs_create_link_nowarn(&link->kobj, &iommu->dev->kobj, "iommu");
119 if (ret)
120 sysfs_remove_link_from_group(&iommu->dev->kobj, "devices",
121 dev_name(link));
122
123 return ret;
124}
125
126void iommu_device_unlink(struct iommu_device *iommu, struct device *link)
127{
128 if (!iommu || IS_ERR(iommu))
129 return;
130
131 sysfs_remove_link(&link->kobj, "iommu");
132 sysfs_remove_link_from_group(&iommu->dev->kobj, "devices", dev_name(link));
133}