3 * generic helper functions for video4linux capture buffers, to handle
4 * memory management and PCI DMA.
5 * Right now, bttv, saa7134, saa7146 and cx88 use it.
7 * The functions expect the hardware being able to scatter gatter
8 * (i.e. the buffers are not linear in physical memory, but fragmented
9 * into PAGE_SIZE chunks). They also assume the driver does not need
10 * to touch the video data.
12 * device specific map/unmap/sync stuff now are mapped as file operations
13 * to allow its usage by USB and virtual devices.
15 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
16 * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
17 * (c) 2006 Ted Walther and John Sokol
19 * This program is free software; you can redistribute it and/or modify
20 * it under the terms of the GNU General Public License as published by
21 * the Free Software Foundation; either version 2 of the License, or
22 * (at your option) any later version.
25 #include <linux/videodev2.h>
29 /* --------------------------------------------------------------------- */
32 * Return a scatterlist for some page-aligned vmalloc()'ed memory
33 * block (NULL on errors). Memory for the scatterlist is allocated
34 * using kmalloc. The caller must free the memory.
36 struct scatterlist
* videobuf_vmalloc_to_sg(unsigned char *virt
, int nr_pages
);
39 * Return a scatterlist for a an array of userpages (NULL on errors).
40 * Memory for the scatterlist is allocated using kmalloc. The caller
41 * must free the memory.
43 struct scatterlist
* videobuf_pages_to_sg(struct page
**pages
, int nr_pages
,
46 struct videobuf_buffer
;
47 struct videobuf_queue
;
49 /* --------------------------------------------------------------------- */
52 * A small set of helper functions to manage buffers (both userland
53 * and kernel) for DMA.
55 * videobuf_dma_init_*()
56 * creates a buffer. The userland version takes a userspace
57 * pointer + length. The kernel version just wants the size and
58 * does memory allocation too using vmalloc_32().
61 * see Documentation/DMA-mapping.txt, these functions to
62 * basically the same. The map function does also build a
63 * scatterlist for the buffer (and unmap frees it ...)
70 struct videobuf_dmabuf
{
73 /* for userland buffer */
77 /* for kernel buffers */
80 /* for overlay buffers (pci-pci dma) */
84 struct scatterlist
*sglist
;
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
,
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
);
99 int videobuf_dma_map(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
);
100 int videobuf_dma_sync(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
);
101 int videobuf_dma_unmap(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
);
103 /*FIXME: these variants are used only on *-alsa code, where videobuf is
106 int videobuf_pci_dma_map(struct pci_dev
*pci
,struct videobuf_dmabuf
*dma
);
107 int videobuf_pci_dma_unmap(struct pci_dev
*pci
,struct videobuf_dmabuf
*dma
);
109 /* --------------------------------------------------------------------- */
112 * A small set of helper functions to manage video4linux buffers.
114 * struct videobuf_buffer holds the data structures used by the helper
115 * functions, additionally some commonly used fields for v4l buffers
116 * (width, height, lists, waitqueue) are in there. That struct should
117 * be used as first element in the drivers buffer struct.
119 * about the mmap helpers (videobuf_mmap_*):
121 * The mmaper function allows to map any subset of contingous buffers.
122 * This includes one mmap() call for all buffers (which the original
123 * video4linux API uses) as well as one mmap() for every single buffer
126 * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
127 * userspace address + size which can be feeded into the
128 * videobuf_dma_init_user function listed above.
132 struct videobuf_mapping
{
136 struct videobuf_queue
*q
;
139 enum videobuf_state
{
140 STATE_NEEDS_INIT
= 0,
149 struct videobuf_buffer
{
153 /* info about the buffer */
156 unsigned int bytesperline
; /* use only if != 0 */
159 enum v4l2_field field
;
160 enum videobuf_state state
;
161 struct videobuf_dmabuf dma
;
162 struct list_head stream
; /* QBUF/DQBUF list */
164 /* for mmap'ed buffers */
165 enum v4l2_memory memory
;
166 size_t boff
; /* buffer offset (mmap + overlay) */
167 size_t bsize
; /* buffer size */
168 unsigned long baddr
; /* buffer addr (userland ptr!) */
169 struct videobuf_mapping
*map
;
171 /* touched by irq handler */
172 struct list_head queue
;
173 wait_queue_head_t done
;
174 unsigned int field_count
;
178 typedef int (vb_map_sg_t
)(void *dev
,struct scatterlist
*sglist
,int nr_pages
,
182 struct videobuf_queue_ops
{
183 int (*buf_setup
)(struct videobuf_queue
*q
,
184 unsigned int *count
, unsigned int *size
);
185 int (*buf_prepare
)(struct videobuf_queue
*q
,
186 struct videobuf_buffer
*vb
,
187 enum v4l2_field field
);
188 void (*buf_queue
)(struct videobuf_queue
*q
,
189 struct videobuf_buffer
*vb
);
190 void (*buf_release
)(struct videobuf_queue
*q
,
191 struct videobuf_buffer
*vb
);
193 /* Helper operations - device dependent.
194 * If null, videobuf_init defaults all to PCI handling
197 vb_map_sg_t
*vb_map_sg
;
198 vb_map_sg_t
*vb_dma_sync_sg
;
199 vb_map_sg_t
*vb_unmap_sg
;
202 struct videobuf_queue
{
205 void *dev
; /* on pci, points to struct pci_dev */
207 enum v4l2_buf_type type
;
208 unsigned int inputs
; /* for V4L2_BUF_FLAG_INPUT */
210 enum v4l2_field field
;
211 enum v4l2_field last
; /* for field=V4L2_FIELD_ALTERNATE */
212 struct videobuf_buffer
*bufs
[VIDEO_MAX_FRAME
];
213 struct videobuf_queue_ops
*ops
;
215 /* capture via mmap() + ioctl(QBUF/DQBUF) */
216 unsigned int streaming
;
217 struct list_head stream
;
219 /* capture via read() */
220 unsigned int reading
;
221 unsigned int read_off
;
222 struct videobuf_buffer
*read_buf
;
224 /* driver private data */
228 void* videobuf_alloc(unsigned int size
);
229 int videobuf_waiton(struct videobuf_buffer
*vb
, int non_blocking
, int intr
);
230 int videobuf_iolock(struct videobuf_queue
* q
, struct videobuf_buffer
*vb
,
231 struct v4l2_framebuffer
*fbuf
);
233 /* Maps fops to PCI stuff */
234 void videobuf_queue_pci(struct videobuf_queue
* q
);
236 void videobuf_queue_init(struct videobuf_queue
*q
,
237 struct videobuf_queue_ops
*ops
,
240 enum v4l2_buf_type type
,
241 enum v4l2_field field
,
244 int videobuf_queue_is_busy(struct videobuf_queue
*q
);
245 void videobuf_queue_cancel(struct videobuf_queue
*q
);
247 enum v4l2_field
videobuf_next_field(struct videobuf_queue
*q
);
248 void videobuf_status(struct v4l2_buffer
*b
, struct videobuf_buffer
*vb
,
249 enum v4l2_buf_type type
);
250 int videobuf_reqbufs(struct videobuf_queue
*q
,
251 struct v4l2_requestbuffers
*req
);
252 int videobuf_querybuf(struct videobuf_queue
*q
, struct v4l2_buffer
*b
);
253 int videobuf_qbuf(struct videobuf_queue
*q
,
254 struct v4l2_buffer
*b
);
255 int videobuf_dqbuf(struct videobuf_queue
*q
,
256 struct v4l2_buffer
*b
, int nonblocking
);
257 int videobuf_streamon(struct videobuf_queue
*q
);
258 int videobuf_streamoff(struct videobuf_queue
*q
);
260 int videobuf_read_start(struct videobuf_queue
*q
);
261 void videobuf_read_stop(struct videobuf_queue
*q
);
262 ssize_t
videobuf_read_stream(struct videobuf_queue
*q
,
263 char __user
*data
, size_t count
, loff_t
*ppos
,
264 int vbihack
, int nonblocking
);
265 ssize_t
videobuf_read_one(struct videobuf_queue
*q
,
266 char __user
*data
, size_t count
, loff_t
*ppos
,
268 unsigned int videobuf_poll_stream(struct file
*file
,
269 struct videobuf_queue
*q
,
272 int videobuf_mmap_setup(struct videobuf_queue
*q
,
273 unsigned int bcount
, unsigned int bsize
,
274 enum v4l2_memory memory
);
275 int videobuf_mmap_free(struct videobuf_queue
*q
);
276 int videobuf_mmap_mapper(struct videobuf_queue
*q
,
277 struct vm_area_struct
*vma
);
279 /* --------------------------------------------------------------------- */