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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 | * Return a scatterlist for some page-aligned vmalloc()'ed memory |
29 | * block (NULL on errors). Memory for the scatterlist is allocated |
30 | * using kmalloc. The caller must free the memory. |
31 | */ |
32 | struct scatterlist *videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages); |
33 | |
34 | /* |
35 | * Return a scatterlist for a an array of userpages (NULL on errors). |
36 | * Memory for the scatterlist is allocated using kmalloc. The caller |
37 | * must free the memory. |
38 | */ |
39 | struct scatterlist *videobuf_pages_to_sg(struct page **pages, int nr_pages, |
40 | int offset); |
41 | |
42 | /* --------------------------------------------------------------------- */ |
43 | |
44 | /* |
45 | * A small set of helper functions to manage buffers (both userland |
46 | * and kernel) for DMA. |
47 | * |
48 | * videobuf_dma_init_*() |
49 | * creates a buffer. The userland version takes a userspace |
50 | * pointer + length. The kernel version just wants the size and |
51 | * does memory allocation too using vmalloc_32(). |
52 | * |
53 | * videobuf_dma_*() |
54 | * see Documentation/PCI/PCI-DMA-mapping.txt, these functions to |
55 | * basically the same. The map function does also build a |
56 | * scatterlist for the buffer (and unmap frees it ...) |
57 | * |
58 | * videobuf_dma_free() |
59 | * no comment ... |
60 | * |
61 | */ |
62 | |
63 | struct videobuf_dmabuf { |
64 | u32 magic; |
65 | |
66 | /* for userland buffer */ |
67 | int offset; |
68 | struct page **pages; |
69 | |
70 | /* for kernel buffers */ |
71 | void *vmalloc; |
72 | |
73 | /* for overlay buffers (pci-pci dma) */ |
74 | dma_addr_t bus_addr; |
75 | |
76 | /* common */ |
77 | struct scatterlist *sglist; |
78 | int sglen; |
79 | int nr_pages; |
80 | int direction; |
81 | }; |
82 | |
83 | struct videobuf_dma_sg_memory { |
84 | u32 magic; |
85 | |
86 | /* for mmap'ed buffers */ |
87 | struct videobuf_dmabuf dma; |
88 | }; |
89 | |
90 | void videobuf_dma_init(struct videobuf_dmabuf *dma); |
91 | int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction, |
92 | unsigned long data, unsigned long size); |
93 | int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction, |
94 | int nr_pages); |
95 | int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction, |
96 | dma_addr_t addr, int nr_pages); |
97 | int videobuf_dma_free(struct videobuf_dmabuf *dma); |
98 | |
99 | int videobuf_dma_map(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); |
102 | |
103 | void *videobuf_sg_alloc(size_t size); |
104 | |
105 | void videobuf_queue_sg_init(struct videobuf_queue *q, |
106 | const struct videobuf_queue_ops *ops, |
107 | struct device *dev, |
108 | spinlock_t *irqlock, |
109 | enum v4l2_buf_type type, |
110 | enum v4l2_field field, |
111 | unsigned int msize, |
112 | void *priv); |
113 | |
114 | /*FIXME: these variants are used only on *-alsa code, where videobuf is |
115 | * used without queue |
116 | */ |
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); |
119 | |
120 | #endif /* _VIDEOBUF_DMA_SG_H */ |
121 | |
122 |
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