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 * 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 } 135