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> 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 */ 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 * 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 */ 57 int 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 device_initialize(&iommu->dev); 66 67 iommu->dev.class = &iommu_class; 68 iommu->dev.parent = parent; 69 iommu->dev.groups = groups; 70 71 va_start(vargs, fmt); 72 ret = kobject_set_name_vargs(&iommu->dev.kobj, fmt, vargs); 73 va_end(vargs); 74 if (ret) 75 goto error; 76 77 ret = device_add(&iommu->dev); 78 if (ret) 79 goto error; 80 81 return 0; 82 83 error: 84 put_device(&iommu->dev); 85 return ret; 86 } 87 88 void iommu_device_sysfs_remove(struct iommu_device *iommu) 89 { 90 device_unregister(&iommu->dev); 91 } 92 /* 93 * IOMMU drivers can indicate a device is managed by a given IOMMU using 94 * this interface. A link to the device will be created in the "devices" 95 * directory of the IOMMU device in sysfs and an "iommu" link will be 96 * created under the linked device, pointing back at the IOMMU device. 97 */ 98 int iommu_device_link(struct iommu_device *iommu, struct device *link) 99 { 100 int ret; 101 102 if (!iommu || IS_ERR(iommu)) 103 return -ENODEV; 104 105 ret = sysfs_add_link_to_group(&iommu->dev.kobj, "devices", 106 &link->kobj, dev_name(link)); 107 if (ret) 108 return ret; 109 110 ret = sysfs_create_link_nowarn(&link->kobj, &iommu->dev.kobj, "iommu"); 111 if (ret) 112 sysfs_remove_link_from_group(&iommu->dev.kobj, "devices", 113 dev_name(link)); 114 115 return ret; 116 } 117 118 void iommu_device_unlink(struct iommu_device *iommu, struct device *link) 119 { 120 if (!iommu || IS_ERR(iommu)) 121 return; 122 123 sysfs_remove_link(&link->kobj, "iommu"); 124 sysfs_remove_link_from_group(&iommu->dev.kobj, "devices", dev_name(link)); 125 } 126