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().
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 ...)
46 struct videobuf_dmabuf
{
49 /* for userland buffer */
54 /* for kernel buffers */
56 struct page
**vaddr_pages
;
60 /* for overlay buffers (pci-pci dma) */
64 struct scatterlist
*sglist
;
70 struct videobuf_dma_sg_memory
{
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
,
98 enum v4l2_buf_type type
,
99 enum v4l2_field field
,
102 struct mutex
*ext_lock
);
104 #endif /* _VIDEOBUF_DMA_SG_H */