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
21 #include <media/videobuf-core.h>
23 /* --------------------------------------------------------------------- */
26 * Return a scatterlist for some page-aligned vmalloc()'ed memory
27 * block (NULL on errors). Memory for the scatterlist is allocated
28 * using kmalloc. The caller must free the memory.
30 struct scatterlist
* videobuf_vmalloc_to_sg(unsigned char *virt
, int nr_pages
);
33 * Return a scatterlist for a an array of userpages (NULL on errors).
34 * Memory for the scatterlist is allocated using kmalloc. The caller
35 * must free the memory.
37 struct scatterlist
* videobuf_pages_to_sg(struct page
**pages
, int nr_pages
,
40 /* --------------------------------------------------------------------- */
43 * A small set of helper functions to manage buffers (both userland
44 * and kernel) for DMA.
46 * videobuf_dma_init_*()
47 * creates a buffer. The userland version takes a userspace
48 * pointer + length. The kernel version just wants the size and
49 * does memory allocation too using vmalloc_32().
52 * see Documentation/PCI/PCI-DMA-mapping.txt, these functions to
53 * basically the same. The map function does also build a
54 * scatterlist for the buffer (and unmap frees it ...)
61 struct videobuf_dmabuf
{
64 /* for userland buffer */
68 /* for kernel buffers */
71 /* for overlay buffers (pci-pci dma) */
75 struct scatterlist
*sglist
;
81 struct videobuf_dma_sg_memory
85 /* for mmap'ed buffers */
86 struct videobuf_dmabuf dma
;
89 void videobuf_dma_init(struct videobuf_dmabuf
*dma
);
90 int videobuf_dma_init_user(struct videobuf_dmabuf
*dma
, int direction
,
91 unsigned long data
, unsigned long size
);
92 int videobuf_dma_init_kernel(struct videobuf_dmabuf
*dma
, int direction
,
94 int videobuf_dma_init_overlay(struct videobuf_dmabuf
*dma
, int direction
,
95 dma_addr_t addr
, int nr_pages
);
96 int videobuf_dma_free(struct videobuf_dmabuf
*dma
);
98 int videobuf_dma_map(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
);
99 int videobuf_dma_sync(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
);
100 int videobuf_dma_unmap(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
);
101 struct videobuf_dmabuf
*videobuf_to_dma (struct videobuf_buffer
*buf
);
103 void *videobuf_sg_alloc(size_t size
);
105 void videobuf_queue_sg_init(struct videobuf_queue
* q
,
106 const struct videobuf_queue_ops
*ops
,
109 enum v4l2_buf_type type
,
110 enum v4l2_field field
,
114 /*FIXME: these variants are used only on *-alsa code, where videobuf is
117 int videobuf_sg_dma_map(struct device
*dev
, struct videobuf_dmabuf
*dma
);
118 int videobuf_sg_dma_unmap(struct device
*dev
, struct videobuf_dmabuf
*dma
);
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