LXR linux-bk/include/media/video-buf.h

   1/*
   2 * $Id: video-buf.h,v 1.9 2004/11/07 13:17:15 kraxel Exp $
   3 *
   4 * generic helper functions for video4linux capture buffers, to handle
   5 * memory management and PCI DMA.  Right now bttv + saa7134 use it.
   6 *
   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 (thus it is probably not useful for USB as
  11 * data often must be uncompressed by the drivers).
  12 *
  13 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
  14 *
  15 * This program is free software; you can redistribute it and/or modify
  16 * it under the terms of the GNU General Public License as published by
  17 * the Free Software Foundation; either version 2 of the License, or
  18 * (at your option) any later version.
  19 */
  20
  21#include <linux/videodev.h>
  22
  23#define UNSET (-1U)
  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 */
  32struct 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 */
  39struct 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_pci_*()
  54 *      see Documentation/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
  63struct 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
  83void videobuf_dma_init(struct videobuf_dmabuf *dma);
  84int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
  85                           unsigned long data, unsigned long size);
  86int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
  87                             int nr_pages);
  88int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
  89                              dma_addr_t addr, int nr_pages);
  90int videobuf_dma_pci_map(struct pci_dev *dev, struct videobuf_dmabuf *dma);
  91int videobuf_dma_pci_sync(struct pci_dev *dev,
  92                          struct videobuf_dmabuf *dma);
  93int videobuf_dma_pci_unmap(struct pci_dev *dev, struct videobuf_dmabuf *dma);
  94int videobuf_dma_free(struct videobuf_dmabuf *dma);
  95
  96/* --------------------------------------------------------------------- */
  97
  98/*
  99 * A small set of helper functions to manage video4linux buffers.
 100 *
 101 * struct videobuf_buffer holds the data structures used by the helper
 102 * functions, additionally some commonly used fields for v4l buffers
 103 * (width, height, lists, waitqueue) are in there.  That struct should
 104 * be used as first element in the drivers buffer struct.
 105 *
 106 * about the mmap helpers (videobuf_mmap_*):
 107 *
 108 * The mmaper function allows to map any subset of contingous buffers.
 109 * This includes one mmap() call for all buffers (which the original
 110 * video4linux API uses) as well as one mmap() for every single buffer
 111 * (which v4l2 uses).
 112 *
 113 * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
 114 * userspace address + size which can be feeded into the
 115 * videobuf_dma_init_user function listed above.
 116 *
 117 */
 118
 119struct videobuf_buffer;
 120struct videobuf_queue;
 121
 122struct videobuf_mapping {
 123        unsigned int count;
 124        unsigned long start;
 125        unsigned long end;
 126        struct videobuf_queue *q;
 127};
 128
 129enum videobuf_state {
 130        STATE_NEEDS_INIT = 0,
 131        STATE_PREPARED   = 1,
 132        STATE_QUEUED     = 2,
 133        STATE_ACTIVE     = 3,
 134        STATE_DONE       = 4,
 135        STATE_ERROR      = 5,
 136        STATE_IDLE       = 6,
 137};
 138
 139struct videobuf_buffer {
 140        unsigned int            i;
 141        u32                     magic;
 142
 143        /* info about the buffer */
 144        unsigned int            width;
 145        unsigned int            height;
 146        unsigned int            bytesperline; /* use only if != 0 */
 147        unsigned long           size;
 148        unsigned int            input;
 149        enum v4l2_field         field;
 150        enum videobuf_state     state;
 151        struct videobuf_dmabuf  dma;
 152        struct list_head        stream;  /* QBUF/DQBUF list */
 153
 154        /* for mmap'ed buffers */
 155        enum v4l2_memory        memory;
 156        size_t                  boff;    /* buffer offset (mmap + overlay) */
 157        size_t                  bsize;   /* buffer size */
 158        unsigned long           baddr;   /* buffer addr (userland ptr!) */
 159        struct videobuf_mapping *map;
 160
 161        /* touched by irq handler */
 162        struct list_head        queue;
 163        wait_queue_head_t       done;
 164        unsigned int            field_count;
 165        struct timeval          ts;
 166};
 167
 168struct videobuf_queue_ops {
 169        int (*buf_setup)(struct videobuf_queue *q,
 170                         unsigned int *count, unsigned int *size);
 171        int (*buf_prepare)(struct videobuf_queue *q,
 172                           struct videobuf_buffer *vb,
 173                           enum v4l2_field field);
 174        void (*buf_queue)(struct videobuf_queue *q,
 175                          struct videobuf_buffer *vb);
 176        void (*buf_release)(struct videobuf_queue *q,
 177                            struct videobuf_buffer *vb);
 178};
 179
 180struct videobuf_queue {
 181        struct semaphore           lock;
 182        spinlock_t                 *irqlock;
 183        struct pci_dev             *pci;
 184
 185        enum v4l2_buf_type         type;
 186        unsigned int               inputs; /* for V4L2_BUF_FLAG_INPUT */
 187        unsigned int               msize;
 188        enum v4l2_field            field;
 189        enum v4l2_field            last;   /* for field=V4L2_FIELD_ALTERNATE */
 190        struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
 191        struct videobuf_queue_ops  *ops;
 192
 193        /* capture via mmap() + ioctl(QBUF/DQBUF) */
 194        unsigned int               streaming;
 195        struct list_head           stream;
 196
 197        /* capture via read() */
 198        unsigned int               reading;
 199        unsigned int               read_off;
 200        struct videobuf_buffer     *read_buf;
 201
 202        /* driver private data */
 203        void                       *priv_data;
 204};
 205
 206void* videobuf_alloc(unsigned int size);
 207int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
 208int videobuf_iolock(struct pci_dev *pci, struct videobuf_buffer *vb,
 209                    struct v4l2_framebuffer *fbuf);
 210
 211void videobuf_queue_init(struct videobuf_queue *q,
 212                         struct videobuf_queue_ops *ops,
 213                         struct pci_dev *pci,
 214                         spinlock_t *irqlock,
 215                         enum v4l2_buf_type type,
 216                         enum v4l2_field field,
 217                         unsigned int msize,
 218                         void *priv);
 219int  videobuf_queue_is_busy(struct videobuf_queue *q);
 220void videobuf_queue_cancel(struct videobuf_queue *q);
 221
 222enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 223void videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb,
 224                     enum v4l2_buf_type type);
 225int videobuf_reqbufs(struct videobuf_queue *q,
 226                     struct v4l2_requestbuffers *req);
 227int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 228int videobuf_qbuf(struct videobuf_queue *q,
 229                  struct v4l2_buffer *b);
 230int videobuf_dqbuf(struct videobuf_queue *q,
 231                   struct v4l2_buffer *b, int nonblocking);
 232int videobuf_streamon(struct videobuf_queue *q);
 233int videobuf_streamoff(struct videobuf_queue *q);
 234
 235int videobuf_read_start(struct videobuf_queue *q);
 236void videobuf_read_stop(struct videobuf_queue *q);
 237ssize_t videobuf_read_stream(struct videobuf_queue *q,
 238                             char __user *data, size_t count, loff_t *ppos,
 239                             int vbihack, int nonblocking);
 240ssize_t videobuf_read_one(struct videobuf_queue *q,
 241                          char __user *data, size_t count, loff_t *ppos,
 242                          int nonblocking);
 243unsigned int videobuf_poll_stream(struct file *file,
 244                                  struct videobuf_queue *q,
 245                                  poll_table *wait);
 246
 247int videobuf_mmap_setup(struct videobuf_queue *q,
 248                        unsigned int bcount, unsigned int bsize,
 249                        enum v4l2_memory memory);
 250int videobuf_mmap_free(struct videobuf_queue *q);
 251int videobuf_mmap_mapper(struct videobuf_queue *q,
 252                         struct vm_area_struct *vma);
 253
 254/* --------------------------------------------------------------------- */
 255
 256/*
 257 * Local variables:
 258 * c-basic-offset: 8
 259 * End:
 260 */
 261