1/*
2 * helper functions for SG DMA video4linux capture buffers
3 *
4 * The functions expect the hardware being able to scatter gather
5 * (i.e. the buffers are not linear in physical memory, but fragmented
6 * into PAGE_SIZE chunks).  They also assume the driver does not need
7 * to touch the video data.
8 *
9 * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
10 *
11 * Highly based on video-buf written originally by:
12 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
13 * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
14 * (c) 2006 Ted Walther and John Sokol
15 *
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License as published by
18 * the Free Software Foundation; either version 2
19 */
20#ifndef _VIDEOBUF_DMA_SG_H
21#define _VIDEOBUF_DMA_SG_H
22
23#include <media/videobuf-core.h>
24
25/* --------------------------------------------------------------------- */
26
27/*
28 * A small set of helper functions to manage buffers (both userland
29 * and kernel) for DMA.
30 *
31 * videobuf_dma_init_*()
32 *	creates a buffer.  The userland version takes a userspace
33 *	pointer + length.  The kernel version just wants the size and
34 *	does memory allocation too using vmalloc_32().
35 *
36 * videobuf_dma_*()
37 *	see Documentation/DMA-API-HOWTO.txt, these functions to
38 *	basically the same.  The map function does also build a
39 *	scatterlist for the buffer (and unmap frees it ...)
40 *
41 * videobuf_dma_free()
42 *	no comment ...
43 *
44 */
45
46struct videobuf_dmabuf {
47	u32                 magic;
48
49	/* for userland buffer */
50	int                 offset;
51	size_t		    size;
52	struct page         **pages;
53
54	/* for kernel buffers */
55	void                *vaddr;
56	struct page         **vaddr_pages;
57	dma_addr_t          *dma_addr;
58	struct device       *dev;
59
60	/* for overlay buffers (pci-pci dma) */
61	dma_addr_t          bus_addr;
62
63	/* common */
64	struct scatterlist  *sglist;
65	int                 sglen;
66	int                 nr_pages;
67	int                 direction;
68};
69
70struct videobuf_dma_sg_memory {
71	u32                 magic;
72
73	/* for mmap'ed buffers */
74	struct videobuf_dmabuf  dma;
75};
76
77/*
78 * Scatter-gather DMA buffer API.
79 *
80 * These functions provide a simple way to create a page list and a
81 * scatter-gather list from a kernel, userspace of physical address and map the
82 * memory for DMA operation.
83 *
84 * Despite the name, this is totally unrelated to videobuf, except that
85 * videobuf-dma-sg uses the same API internally.
86 */
87int videobuf_dma_free(struct videobuf_dmabuf *dma);
88
89int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma);
90struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf);
91
92void *videobuf_sg_alloc(size_t size);
93
94void videobuf_queue_sg_init(struct videobuf_queue *q,
95			 const struct videobuf_queue_ops *ops,
96			 struct device *dev,
97			 spinlock_t *irqlock,
98			 enum v4l2_buf_type type,
99			 enum v4l2_field field,
100			 unsigned int msize,
101			 void *priv,
102			 struct mutex *ext_lock);
103
104#endif /* _VIDEOBUF_DMA_SG_H */
105
106