// SPDX-License-Identifier: GPL-2.0-only /* * IOMMU sysfs class support * * Copyright (C) 2014 Red Hat, Inc. All rights reserved. * Author: Alex Williamson <alex.williamson@redhat.com> */ #include <linux/device.h> #include <linux/iommu.h> #include <linux/init.h> #include <linux/slab.h> /* * We provide a common class "devices" group which initially has no attributes. * As devices are added to the IOMMU, we'll add links to the group. */ static struct attribute *devices_attr[] = { NULL, }; static const struct attribute_group devices_attr_group = { .name = "devices", .attrs = devices_attr, }; static const struct attribute_group *dev_groups[] = { &devices_attr_group, NULL, }; static void release_device(struct device *dev) { kfree(dev); } static struct class iommu_class = { .name = "iommu", .dev_release = release_device, .dev_groups = dev_groups, }; static int __init iommu_dev_init(void) { return class_register(&iommu_class); } postcore_initcall(iommu_dev_init); /* * Init the struct device for the IOMMU. IOMMU specific attributes can * be provided as an attribute group, allowing a unique namespace per * IOMMU type. */ int iommu_device_sysfs_add(struct iommu_device *iommu, struct device *parent, const struct attribute_group **groups, const char *fmt, ...) { va_list vargs; int ret; iommu->dev = kzalloc(sizeof(*iommu->dev), GFP_KERNEL); if (!iommu->dev) return -ENOMEM; device_initialize(iommu->dev); iommu->dev->class = &iommu_class; iommu->dev->parent = parent; iommu->dev->groups = groups; va_start(vargs, fmt); ret = kobject_set_name_vargs(&iommu->dev->kobj, fmt, vargs); va_end(vargs); if (ret) goto error; ret = device_add(iommu->dev); if (ret) goto error; dev_set_drvdata(iommu->dev, iommu); return 0; error: put_device(iommu->dev); return ret; } EXPORT_SYMBOL_GPL(iommu_device_sysfs_add); void iommu_device_sysfs_remove(struct iommu_device *iommu) { dev_set_drvdata(iommu->dev, NULL); device_unregister(iommu->dev); iommu->dev = NULL; } EXPORT_SYMBOL_GPL(iommu_device_sysfs_remove); /* * IOMMU drivers can indicate a device is managed by a given IOMMU using * this interface. A link to the device will be created in the "devices" * directory of the IOMMU device in sysfs and an "iommu" link will be * created under the linked device, pointing back at the IOMMU device. */ int iommu_device_link(struct iommu_device *iommu, struct device *link) { int ret; if (!iommu || IS_ERR(iommu)) return -ENODEV; ret = sysfs_add_link_to_group(&iommu->dev->kobj, "devices", &link->kobj, dev_name(link)); if (ret) return ret; ret = sysfs_create_link_nowarn(&link->kobj, &iommu->dev->kobj, "iommu"); if (ret) sysfs_remove_link_from_group(&iommu->dev->kobj, "devices", dev_name(link)); return ret; } EXPORT_SYMBOL_GPL(iommu_device_link); void iommu_device_unlink(struct iommu_device *iommu, struct device *link) { if (!iommu || IS_ERR(iommu)) return; sysfs_remove_link(&link->kobj, "iommu"); sysfs_remove_link_from_group(&iommu->dev->kobj, "devices", dev_name(link)); } EXPORT_SYMBOL_GPL(iommu_device_unlink);