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c61959ec AW |
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/module.h> | |
ffd78f00 | 15 | #include <linux/slab.h> |
c61959ec AW |
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 | */ | |
21 | static struct attribute *devices_attr[] = { | |
22 | NULL, | |
23 | }; | |
24 | ||
25 | static const struct attribute_group iommu_devices_attr_group = { | |
26 | .name = "devices", | |
27 | .attrs = devices_attr, | |
28 | }; | |
29 | ||
30 | static const struct attribute_group *iommu_dev_groups[] = { | |
31 | &iommu_devices_attr_group, | |
32 | NULL, | |
33 | }; | |
34 | ||
35 | static void iommu_release_device(struct device *dev) | |
36 | { | |
37 | kfree(dev); | |
38 | } | |
39 | ||
40 | static struct class iommu_class = { | |
41 | .name = "iommu", | |
42 | .dev_release = iommu_release_device, | |
43 | .dev_groups = iommu_dev_groups, | |
44 | }; | |
45 | ||
46 | static int __init iommu_dev_init(void) | |
47 | { | |
48 | return class_register(&iommu_class); | |
49 | } | |
50 | postcore_initcall(iommu_dev_init); | |
51 | ||
52 | /* | |
53 | * Create an IOMMU device and return a pointer to it. IOMMU specific | |
54 | * attributes can be provided as an attribute group, allowing a unique | |
55 | * namespace per IOMMU type. | |
56 | */ | |
57 | struct device *iommu_device_create(struct device *parent, void *drvdata, | |
58 | const struct attribute_group **groups, | |
59 | const char *fmt, ...) | |
60 | { | |
61 | struct device *dev; | |
62 | va_list vargs; | |
63 | int ret; | |
64 | ||
65 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); | |
66 | if (!dev) | |
67 | return ERR_PTR(-ENOMEM); | |
68 | ||
69 | device_initialize(dev); | |
70 | ||
71 | dev->class = &iommu_class; | |
72 | dev->parent = parent; | |
73 | dev->groups = groups; | |
74 | dev_set_drvdata(dev, drvdata); | |
75 | ||
76 | va_start(vargs, fmt); | |
77 | ret = kobject_set_name_vargs(&dev->kobj, fmt, vargs); | |
78 | va_end(vargs); | |
79 | if (ret) | |
80 | goto error; | |
81 | ||
82 | ret = device_add(dev); | |
83 | if (ret) | |
84 | goto error; | |
85 | ||
86 | return dev; | |
87 | ||
88 | error: | |
89 | put_device(dev); | |
90 | return ERR_PTR(ret); | |
91 | } | |
92 | ||
93 | void iommu_device_destroy(struct device *dev) | |
94 | { | |
95 | if (!dev || IS_ERR(dev)) | |
96 | return; | |
97 | ||
98 | device_unregister(dev); | |
99 | } | |
100 | ||
101 | /* | |
102 | * IOMMU drivers can indicate a device is managed by a given IOMMU using | |
103 | * this interface. A link to the device will be created in the "devices" | |
104 | * directory of the IOMMU device in sysfs and an "iommu" link will be | |
105 | * created under the linked device, pointing back at the IOMMU device. | |
106 | */ | |
107 | int iommu_device_link(struct device *dev, struct device *link) | |
108 | { | |
109 | int ret; | |
110 | ||
111 | if (!dev || IS_ERR(dev)) | |
112 | return -ENODEV; | |
113 | ||
114 | ret = sysfs_add_link_to_group(&dev->kobj, "devices", | |
115 | &link->kobj, dev_name(link)); | |
116 | if (ret) | |
117 | return ret; | |
118 | ||
119 | ret = sysfs_create_link_nowarn(&link->kobj, &dev->kobj, "iommu"); | |
120 | if (ret) | |
121 | sysfs_remove_link_from_group(&dev->kobj, "devices", | |
122 | dev_name(link)); | |
123 | ||
124 | return ret; | |
125 | } | |
126 | ||
127 | void iommu_device_unlink(struct device *dev, struct device *link) | |
128 | { | |
129 | if (!dev || IS_ERR(dev)) | |
130 | return; | |
131 | ||
132 | sysfs_remove_link(&link->kobj, "iommu"); | |
133 | sysfs_remove_link_from_group(&dev->kobj, "devices", dev_name(link)); | |
134 | } |