linux/include/media/videobuf-core.h
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   1/*
   2 * generic helper functions for handling video4linux capture buffers
   3 *
   4 * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
   5 *
   6 * Highly based on video-buf written originally by:
   7 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
   8 * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
   9 * (c) 2006 Ted Walther and John Sokol
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License as published by
  13 * the Free Software Foundation; either version 2
  14 */
  15
  16#ifndef _VIDEOBUF_CORE_H
  17#define _VIDEOBUF_CORE_H
  18
  19#include <linux/poll.h>
  20#include <linux/videodev2.h>
  21
  22#define UNSET (-1U)
  23
  24
  25struct videobuf_buffer;
  26struct videobuf_queue;
  27
  28/* --------------------------------------------------------------------- */
  29
  30/*
  31 * A small set of helper functions to manage video4linux buffers.
  32 *
  33 * struct videobuf_buffer holds the data structures used by the helper
  34 * functions, additionally some commonly used fields for v4l buffers
  35 * (width, height, lists, waitqueue) are in there.  That struct should
  36 * be used as first element in the drivers buffer struct.
  37 *
  38 * about the mmap helpers (videobuf_mmap_*):
  39 *
  40 * The mmaper function allows to map any subset of contingous buffers.
  41 * This includes one mmap() call for all buffers (which the original
  42 * video4linux API uses) as well as one mmap() for every single buffer
  43 * (which v4l2 uses).
  44 *
  45 * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
  46 * userspace address + size which can be feeded into the
  47 * videobuf_dma_init_user function listed above.
  48 *
  49 */
  50
  51struct videobuf_mapping {
  52        unsigned int count;
  53        struct videobuf_queue *q;
  54};
  55
  56enum videobuf_state {
  57        VIDEOBUF_NEEDS_INIT = 0,
  58        VIDEOBUF_PREPARED   = 1,
  59        VIDEOBUF_QUEUED     = 2,
  60        VIDEOBUF_ACTIVE     = 3,
  61        VIDEOBUF_DONE       = 4,
  62        VIDEOBUF_ERROR      = 5,
  63        VIDEOBUF_IDLE       = 6,
  64};
  65
  66struct videobuf_buffer {
  67        unsigned int            i;
  68        u32                     magic;
  69
  70        /* info about the buffer */
  71        unsigned int            width;
  72        unsigned int            height;
  73        unsigned int            bytesperline; /* use only if != 0 */
  74        unsigned long           size;
  75        enum v4l2_field         field;
  76        enum videobuf_state     state;
  77        struct list_head        stream;  /* QBUF/DQBUF list */
  78
  79        /* touched by irq handler */
  80        struct list_head        queue;
  81        wait_queue_head_t       done;
  82        unsigned int            field_count;
  83        struct timeval          ts;
  84
  85        /* Memory type */
  86        enum v4l2_memory        memory;
  87
  88        /* buffer size */
  89        size_t                  bsize;
  90
  91        /* buffer offset (mmap + overlay) */
  92        size_t                  boff;
  93
  94        /* buffer addr (userland ptr!) */
  95        unsigned long           baddr;
  96
  97        /* for mmap'ed buffers */
  98        struct videobuf_mapping *map;
  99
 100        /* Private pointer to allow specific methods to store their data */
 101        int                     privsize;
 102        void                    *priv;
 103};
 104
 105struct videobuf_queue_ops {
 106        int (*buf_setup)(struct videobuf_queue *q,
 107                         unsigned int *count, unsigned int *size);
 108        int (*buf_prepare)(struct videobuf_queue *q,
 109                           struct videobuf_buffer *vb,
 110                           enum v4l2_field field);
 111        void (*buf_queue)(struct videobuf_queue *q,
 112                          struct videobuf_buffer *vb);
 113        void (*buf_release)(struct videobuf_queue *q,
 114                            struct videobuf_buffer *vb);
 115};
 116
 117#define MAGIC_QTYPE_OPS 0x12261003
 118
 119/* Helper operations - device type dependent */
 120struct videobuf_qtype_ops {
 121        u32                     magic;
 122
 123        struct videobuf_buffer *(*alloc_vb)(size_t size);
 124        void *(*vaddr)          (struct videobuf_buffer *buf);
 125        int (*iolock)           (struct videobuf_queue *q,
 126                                 struct videobuf_buffer *vb,
 127                                 struct v4l2_framebuffer *fbuf);
 128        int (*sync)             (struct videobuf_queue *q,
 129                                 struct videobuf_buffer *buf);
 130        int (*mmap_mapper)      (struct videobuf_queue *q,
 131                                 struct videobuf_buffer *buf,
 132                                 struct vm_area_struct *vma);
 133};
 134
 135struct videobuf_queue {
 136        struct mutex               vb_lock;
 137        struct mutex               *ext_lock;
 138        spinlock_t                 *irqlock;
 139        struct device              *dev;
 140
 141        wait_queue_head_t          wait; /* wait if queue is empty */
 142
 143        enum v4l2_buf_type         type;
 144        unsigned int               msize;
 145        enum v4l2_field            field;
 146        enum v4l2_field            last;   /* for field=V4L2_FIELD_ALTERNATE */
 147        struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
 148        const struct videobuf_queue_ops  *ops;
 149        struct videobuf_qtype_ops  *int_ops;
 150
 151        unsigned int               streaming:1;
 152        unsigned int               reading:1;
 153
 154        /* capture via mmap() + ioctl(QBUF/DQBUF) */
 155        struct list_head           stream;
 156
 157        /* capture via read() */
 158        unsigned int               read_off;
 159        struct videobuf_buffer     *read_buf;
 160
 161        /* driver private data */
 162        void                       *priv_data;
 163};
 164
 165static inline void videobuf_queue_lock(struct videobuf_queue *q)
 166{
 167        if (!q->ext_lock)
 168                mutex_lock(&q->vb_lock);
 169}
 170
 171static inline void videobuf_queue_unlock(struct videobuf_queue *q)
 172{
 173        if (!q->ext_lock)
 174                mutex_unlock(&q->vb_lock);
 175}
 176
 177int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
 178                int non_blocking, int intr);
 179int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
 180                struct v4l2_framebuffer *fbuf);
 181
 182struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q);
 183
 184/* Used on videobuf-dvb */
 185void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
 186                              struct videobuf_buffer *buf);
 187
 188void videobuf_queue_core_init(struct videobuf_queue *q,
 189                         const struct videobuf_queue_ops *ops,
 190                         struct device *dev,
 191                         spinlock_t *irqlock,
 192                         enum v4l2_buf_type type,
 193                         enum v4l2_field field,
 194                         unsigned int msize,
 195                         void *priv,
 196                         struct videobuf_qtype_ops *int_ops,
 197                         struct mutex *ext_lock);
 198int  videobuf_queue_is_busy(struct videobuf_queue *q);
 199void videobuf_queue_cancel(struct videobuf_queue *q);
 200
 201enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 202int videobuf_reqbufs(struct videobuf_queue *q,
 203                     struct v4l2_requestbuffers *req);
 204int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 205int videobuf_qbuf(struct videobuf_queue *q,
 206                  struct v4l2_buffer *b);
 207int videobuf_dqbuf(struct videobuf_queue *q,
 208                   struct v4l2_buffer *b, int nonblocking);
 209int videobuf_streamon(struct videobuf_queue *q);
 210int videobuf_streamoff(struct videobuf_queue *q);
 211
 212void videobuf_stop(struct videobuf_queue *q);
 213
 214int videobuf_read_start(struct videobuf_queue *q);
 215void videobuf_read_stop(struct videobuf_queue *q);
 216ssize_t videobuf_read_stream(struct videobuf_queue *q,
 217                             char __user *data, size_t count, loff_t *ppos,
 218                             int vbihack, int nonblocking);
 219ssize_t videobuf_read_one(struct videobuf_queue *q,
 220                          char __user *data, size_t count, loff_t *ppos,
 221                          int nonblocking);
 222unsigned int videobuf_poll_stream(struct file *file,
 223                                  struct videobuf_queue *q,
 224                                  poll_table *wait);
 225
 226int videobuf_mmap_setup(struct videobuf_queue *q,
 227                        unsigned int bcount, unsigned int bsize,
 228                        enum v4l2_memory memory);
 229int __videobuf_mmap_setup(struct videobuf_queue *q,
 230                        unsigned int bcount, unsigned int bsize,
 231                        enum v4l2_memory memory);
 232int videobuf_mmap_free(struct videobuf_queue *q);
 233int videobuf_mmap_mapper(struct videobuf_queue *q,
 234                         struct vm_area_struct *vma);
 235
 236#endif
 237
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