// 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 const 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_obj(*iommu->dev);
        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;

        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;
}

void iommu_device_unlink(struct iommu_device *iommu, struct device *link)
{
        sysfs_remove_link(&link->kobj, "iommu");
        sysfs_remove_link_from_group(&iommu->dev->kobj, "devices", dev_name(link));
}