1 /*
2  * helper functions for SG 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  */
30 struct 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  */
37 struct 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 
61 struct 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 	/* for overlay buffers (pci-pci dma) */
72 	dma_addr_t          bus_addr;
73 
74 	/* common */
75 	struct scatterlist  *sglist;
76 	int                 sglen;
77 	int                 nr_pages;
78 	int                 direction;
79 };
80 
81 struct videobuf_dma_sg_memory
82 {
83 	u32                 magic;
84 
85 	/* for mmap'ed buffers */
86 	struct videobuf_dmabuf  dma;
87 };
88 
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,
93 			     int nr_pages);
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);
97 
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);
102 
103 void *videobuf_sg_alloc(size_t size);
104 
105 void videobuf_queue_sg_init(struct videobuf_queue* q,
106 			 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