1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright 2018-2020 Broadcom.
4 */
5
6#ifndef BCM_VK_SG_H
7#define BCM_VK_SG_H
8
9#include <linux/dma-mapping.h>
10
11struct bcm_vk_dma {
12 /* for userland buffer */
13 struct page **pages;
14 int nr_pages;
15
16 /* common */
17 dma_addr_t handle;
18 /*
19 * sglist is of the following LE format
20 * [U32] num_sg = number of sg addresses (N)
21 * [U32] totalsize = totalsize of data being transferred in sglist
22 * [U32] size[0] = size of data in address0
23 * [U32] addr_l[0] = lower 32-bits of address0
24 * [U32] addr_h[0] = higher 32-bits of address0
25 * ..
26 * [U32] size[N-1] = size of data in addressN-1
27 * [U32] addr_l[N-1] = lower 32-bits of addressN-1
28 * [U32] addr_h[N-1] = higher 32-bits of addressN-1
29 */
30 u32 *sglist;
31#define SGLIST_NUM_SG 0
32#define SGLIST_TOTALSIZE 1
33#define SGLIST_VKDATA_START 2
34
35 int sglen; /* Length (bytes) of sglist */
36 int direction;
37};
38
39struct _vk_data {
40 u32 size; /* data size in bytes */
41 u64 address; /* Pointer to data */
42} __packed;
43
44/*
45 * Scatter-gather DMA buffer API.
46 *
47 * These functions provide a simple way to create a page list and a
48 * scatter-gather list from userspace address and map the memory
49 * for DMA operation.
50 */
51int bcm_vk_sg_alloc(struct device *dev,
52 struct bcm_vk_dma *dma,
53 int dir,
54 struct _vk_data *vkdata,
55 int num);
56
57int bcm_vk_sg_free(struct device *dev, struct bcm_vk_dma *dma, int num,
58 int *proc_cnt);
59
60#endif
61
62

source code of linux/drivers/misc/bcm-vk/bcm_vk_sg.h