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 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 89 error: 90 put_device(iommu->dev); 91 return ret; 92 } 93 94 void 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 */ 106 int 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 } 125 126 void 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 } 134