// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * dma-bufs for virtio exported objects
 *
 * Copyright (C) 2020 Google, Inc.
 */

#include <linux/module.h>
#include <linux/virtio_dma_buf.h>

/**
 * virtio_dma_buf_export - Creates a new dma-buf for a virtio exported object
 * @exp_info: [in] see dma_buf_export(). ops MUST refer to a dma_buf_ops
 *      struct embedded in a virtio_dma_buf_ops.
 *
 * This wraps dma_buf_export() to allow virtio drivers to create a dma-buf
 * for an virtio exported object that can be queried by other virtio drivers
 * for the object's UUID.
 */
struct dma_buf *virtio_dma_buf_export
        (const struct dma_buf_export_info *exp_info)
{
        const struct virtio_dma_buf_ops *virtio_ops =
                container_of(exp_info->ops,
                             const struct virtio_dma_buf_ops, ops);

        if (!exp_info->ops ||
            exp_info->ops->attach != &virtio_dma_buf_attach ||
            !virtio_ops->get_uuid) {
                return ERR_PTR(-EINVAL);
        }

        return dma_buf_export(exp_info);
}
EXPORT_SYMBOL(virtio_dma_buf_export);

/**
 * virtio_dma_buf_attach - mandatory attach callback for virtio dma-bufs
 * @dma_buf: [in] buffer to attach
 * @attach: [in] attachment structure
 */
int virtio_dma_buf_attach(struct dma_buf *dma_buf,
                          struct dma_buf_attachment *attach)
{
        int ret;
        const struct virtio_dma_buf_ops *ops =
                container_of(dma_buf->ops,
                             const struct virtio_dma_buf_ops, ops);

        if (ops->device_attach) {
                ret = ops->device_attach(dma_buf, attach);
                if (ret)
                        return ret;
        }
        return 0;
}
EXPORT_SYMBOL(virtio_dma_buf_attach);

/**
 * is_virtio_dma_buf - returns true if the given dma-buf is a virtio dma-buf
 * @dma_buf: buffer to query
 */
bool is_virtio_dma_buf(struct dma_buf *dma_buf)
{
        return dma_buf->ops->attach == &virtio_dma_buf_attach;
}
EXPORT_SYMBOL(is_virtio_dma_buf);

/**
 * virtio_dma_buf_get_uuid - gets a virtio dma-buf's exported object's uuid
 * @dma_buf: [in] buffer to query
 * @uuid: [out] the uuid
 *
 * Returns: 0 on success, negative on failure.
 */
int virtio_dma_buf_get_uuid(struct dma_buf *dma_buf,
                            uuid_t *uuid)
{
        const struct virtio_dma_buf_ops *ops =
                container_of(dma_buf->ops,
                             const struct virtio_dma_buf_ops, ops);

        if (!is_virtio_dma_buf(dma_buf))
                return -EINVAL;

        return ops->get_uuid(dma_buf, uuid);
}
EXPORT_SYMBOL(virtio_dma_buf_get_uuid);

MODULE_DESCRIPTION("dma-bufs for virtio exported objects");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("DMA_BUF");