xref: /openbmc/linux/drivers/iommu/iommu-sysfs.c (revision 9a108996)
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  */
18 static struct attribute *devices_attr[] = {
19 	NULL,
20 };
21 
22 static const struct attribute_group devices_attr_group = {
23 	.name = "devices",
24 	.attrs = devices_attr,
25 };
26 
27 static const struct attribute_group *dev_groups[] = {
28 	&devices_attr_group,
29 	NULL,
30 };
31 
release_device(struct device * dev)32 static void release_device(struct device *dev)
33 {
34 	kfree(dev);
35 }
36 
37 static struct class iommu_class = {
38 	.name = "iommu",
39 	.dev_release = release_device,
40 	.dev_groups = dev_groups,
41 };
42 
iommu_dev_init(void)43 static int __init iommu_dev_init(void)
44 {
45 	return class_register(&iommu_class);
46 }
47 postcore_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  */
iommu_device_sysfs_add(struct iommu_device * iommu,struct device * parent,const struct attribute_group ** groups,const char * fmt,...)54 int 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 
86 error:
87 	put_device(iommu->dev);
88 	return ret;
89 }
90 EXPORT_SYMBOL_GPL(iommu_device_sysfs_add);
91 
iommu_device_sysfs_remove(struct iommu_device * iommu)92 void 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 }
98 EXPORT_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  */
iommu_device_link(struct iommu_device * iommu,struct device * link)106 int 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 
iommu_device_unlink(struct iommu_device * iommu,struct device * link)123 void 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