VisionFive2 Linux kernel

a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900  1) // SPDX-License-Identifier: GPL-2.0-or-later
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900  2) /*
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900  3)  * dma-bufs for virtio exported objects
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900  4)  *
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900  5)  * Copyright (C) 2020 Google, Inc.
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900  6)  */
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900  7) 
9fe2f897499f1 (David Stevens 2020-08-19 12:10:11 +0900  8) #include <linux/module.h>
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900  9) #include <linux/virtio_dma_buf.h>
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 10) 
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 11) /**
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 12)  * virtio_dma_buf_export - Creates a new dma-buf for a virtio exported object
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 13)  * @exp_info: [in] see dma_buf_export(). ops MUST refer to a dma_buf_ops
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 14)  *	struct embedded in a virtio_dma_buf_ops.
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 15)  *
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 16)  * This wraps dma_buf_export() to allow virtio drivers to create a dma-buf
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 17)  * for an virtio exported object that can be queried by other virtio drivers
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 18)  * for the object's UUID.
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 19)  */
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 20) struct dma_buf *virtio_dma_buf_export
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 21) 	(const struct dma_buf_export_info *exp_info)
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 22) {
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 23) 	const struct virtio_dma_buf_ops *virtio_ops =
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 24) 		container_of(exp_info->ops,
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 25) 			     const struct virtio_dma_buf_ops, ops);
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 26) 
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 27) 	if (!exp_info->ops ||
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 28) 	    exp_info->ops->attach != &virtio_dma_buf_attach ||
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 29) 	    !virtio_ops->get_uuid) {
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 30) 		return ERR_PTR(-EINVAL);
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 31) 	}
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 32) 
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 33) 	return dma_buf_export(exp_info);
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 34) }
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 35) EXPORT_SYMBOL(virtio_dma_buf_export);
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 36) 
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 37) /**
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 38)  * virtio_dma_buf_attach - mandatory attach callback for virtio dma-bufs
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 39)  */
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 40) int virtio_dma_buf_attach(struct dma_buf *dma_buf,
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 41) 			  struct dma_buf_attachment *attach)
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 42) {
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 43) 	int ret;
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 44) 	const struct virtio_dma_buf_ops *ops =
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 45) 		container_of(dma_buf->ops,
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 46) 			     const struct virtio_dma_buf_ops, ops);
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 47) 
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 48) 	if (ops->device_attach) {
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 49) 		ret = ops->device_attach(dma_buf, attach);
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 50) 		if (ret)
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 51) 			return ret;
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 52) 	}
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 53) 	return 0;
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 54) }
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 55) EXPORT_SYMBOL(virtio_dma_buf_attach);
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 56) 
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 57) /**
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 58)  * is_virtio_dma_buf - returns true if the given dma-buf is a virtio dma-buf
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 59)  * @dma_buf: buffer to query
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 60)  */
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 61) bool is_virtio_dma_buf(struct dma_buf *dma_buf)
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 62) {
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 63) 	return dma_buf->ops->attach == &virtio_dma_buf_attach;
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 64) }
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 65) EXPORT_SYMBOL(is_virtio_dma_buf);
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 66) 
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 67) /**
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 68)  * virtio_dma_buf_get_uuid - gets a virtio dma-buf's exported object's uuid
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 69)  * @dma_buf: [in] buffer to query
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 70)  * @uuid: [out] the uuid
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 71)  *
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 72)  * Returns: 0 on success, negative on failure.
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 73)  */
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 74) int virtio_dma_buf_get_uuid(struct dma_buf *dma_buf,
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 75) 			    uuid_t *uuid)
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 76) {
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 77) 	const struct virtio_dma_buf_ops *ops =
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 78) 		container_of(dma_buf->ops,
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 79) 			     const struct virtio_dma_buf_ops, ops);
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 80) 
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 81) 	if (!is_virtio_dma_buf(dma_buf))
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 82) 		return -EINVAL;
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 83) 
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 84) 	return ops->get_uuid(dma_buf, uuid);
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 85) }
a0308938ec81c (David Stevens 2020-08-18 16:13:41 +0900 86) EXPORT_SYMBOL(virtio_dma_buf_get_uuid);
9fe2f897499f1 (David Stevens 2020-08-19 12:10:11 +0900 87) 
9fe2f897499f1 (David Stevens 2020-08-19 12:10:11 +0900 88) MODULE_LICENSE("GPL");