perf/abi: Document some more aspects of the perf ABI
[linux/fpc-iii.git] / include / media / videobuf-dma-sg.h
blobd8b27854e3bf1b90f273bb19529f9d6d4a44d20e
1 /*
2 * helper functions for SG DMA video4linux capture buffers
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.
9 * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
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
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
20 #ifndef _VIDEOBUF_DMA_SG_H
21 #define _VIDEOBUF_DMA_SG_H
23 #include <media/videobuf-core.h>
25 /* --------------------------------------------------------------------- */
28 * A small set of helper functions to manage buffers (both userland
29 * and kernel) for DMA.
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().
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 ...)
41 * videobuf_dma_free()
42 * no comment ...
46 struct videobuf_dmabuf {
47 u32 magic;
49 /* for userland buffer */
50 int offset;
51 size_t size;
52 struct page **pages;
54 /* for kernel buffers */
55 void *vaddr;
56 struct page **vaddr_pages;
57 dma_addr_t *dma_addr;
58 struct device *dev;
60 /* for overlay buffers (pci-pci dma) */
61 dma_addr_t bus_addr;
63 /* common */
64 struct scatterlist *sglist;
65 int sglen;
66 int nr_pages;
67 int direction;
70 struct videobuf_dma_sg_memory {
71 u32 magic;
73 /* for mmap'ed buffers */
74 struct videobuf_dmabuf dma;
78 * Scatter-gather DMA buffer API.
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.
84 * Despite the name, this is totally unrelated to videobuf, except that
85 * videobuf-dma-sg uses the same API internally.
87 int videobuf_dma_free(struct videobuf_dmabuf *dma);
89 int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma);
90 struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf);
92 void *videobuf_sg_alloc(size_t size);
94 void 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);
104 #endif /* _VIDEOBUF_DMA_SG_H */