tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * helper functions for PCI DMA video4linux capture buffers
3 *
4 * The functions expect the hardware being able to scatter gatter
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
21#include <media/videobuf-core.h>
22
23/* --------------------------------------------------------------------- */
24
25/*
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.
29 */
30struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages);
31
32/*
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.
36 */
37struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages,
38 int offset);
39
40/* --------------------------------------------------------------------- */
41
42/*
43 * A small set of helper functions to manage buffers (both userland
44 * and kernel) for DMA.
45 *
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().
50 *
51 * videobuf_dma_*()
52 * see Documentation/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 ...)
55 *
56 * videobuf_dma_free()
57 * no comment ...
58 *
59 */
60
61struct videobuf_dmabuf {
62 u32 magic;
63
64 /* for userland buffer */
65 int offset;
66 struct page **pages;
67
68 /* for kernel buffers */
69 void *vmalloc;
70
71 /* Stores the userspace pointer to vmalloc area */
72 void *varea;
73
74 /* for overlay buffers (pci-pci dma) */
75 dma_addr_t bus_addr;
76
77 /* common */
78 struct scatterlist *sglist;
79 int sglen;
80 int nr_pages;
81 int direction;
82};
83
84struct videbuf_pci_sg_memory
85{
86 u32 magic;
87
88 /* for mmap'ed buffers */
89 struct videobuf_dmabuf dma;
90};
91
92void videobuf_dma_init(struct videobuf_dmabuf *dma);
93int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
94 unsigned long data, unsigned long size);
95int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
96 int nr_pages);
97int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
98 dma_addr_t addr, int nr_pages);
99int videobuf_dma_free(struct videobuf_dmabuf *dma);
100
101int videobuf_dma_map(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
102int videobuf_dma_sync(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
103int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma);
104struct videobuf_dmabuf *videobuf_to_dma (struct videobuf_buffer *buf);
105
106void *videobuf_pci_alloc (size_t size);
107
108void videobuf_queue_pci_init(struct videobuf_queue* q,
109 struct videobuf_queue_ops *ops,
110 void *dev,
111 spinlock_t *irqlock,
112 enum v4l2_buf_type type,
113 enum v4l2_field field,
114 unsigned int msize,
115 void *priv);
116
117 /*FIXME: these variants are used only on *-alsa code, where videobuf is
118 * used without queue
119 */
120int videobuf_pci_dma_map(struct pci_dev *pci,struct videobuf_dmabuf *dma);
121int videobuf_pci_dma_unmap(struct pci_dev *pci,struct videobuf_dmabuf *dma);
122