include/media/videobuf-core.h

   1 /*
   2  * generic helper functions for handling video4linux capture buffers
   3  *
   4  * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.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@kernel.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
  25 struct videobuf_buffer;
  26 struct 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 contiguous 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
  51 struct videobuf_mapping {
  52         unsigned int count;
  53         struct videobuf_queue *q;
  54 };
  55
  56 enum 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
  66 struct 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
 105 struct 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 */
 120 struct 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
 135 struct 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
 165 static inline void videobuf_queue_lock(struct videobuf_queue *q)
 166 {
 167         if (!q->ext_lock)
 168                 mutex_lock(&q->vb_lock);
 169 }
 170
 171 static inline void videobuf_queue_unlock(struct videobuf_queue *q)
 172 {
 173         if (!q->ext_lock)
 174                 mutex_unlock(&q->vb_lock);
 175 }
 176
 177 int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
 178                 int non_blocking, int intr);
 179 int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
 180                 struct v4l2_framebuffer *fbuf);
 181
 182 struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q);
 183
 184 /* Used on videobuf-dvb */
 185 void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
 186                               struct videobuf_buffer *buf);
 187
 188 void 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);
 198 int  videobuf_queue_is_busy(struct videobuf_queue *q);
 199 void videobuf_queue_cancel(struct videobuf_queue *q);
 200
 201 enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 202 int videobuf_reqbufs(struct videobuf_queue *q,
 203                      struct v4l2_requestbuffers *req);
 204 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 205 int videobuf_qbuf(struct videobuf_queue *q,
 206                   struct v4l2_buffer *b);
 207 int videobuf_dqbuf(struct videobuf_queue *q,
 208                    struct v4l2_buffer *b, int nonblocking);
 209 int videobuf_streamon(struct videobuf_queue *q);
 210 int videobuf_streamoff(struct videobuf_queue *q);
 211
 212 void videobuf_stop(struct videobuf_queue *q);
 213
 214 int videobuf_read_start(struct videobuf_queue *q);
 215 void videobuf_read_stop(struct videobuf_queue *q);
 216 ssize_t videobuf_read_stream(struct videobuf_queue *q,
 217                              char __user *data, size_t count, loff_t *ppos,
 218                              int vbihack, int nonblocking);
 219 ssize_t videobuf_read_one(struct videobuf_queue *q,
 220                           char __user *data, size_t count, loff_t *ppos,
 221                           int nonblocking);
 222 __poll_t videobuf_poll_stream(struct file *file,
 223                                   struct videobuf_queue *q,
 224                                   poll_table *wait);
 225
 226 int videobuf_mmap_setup(struct videobuf_queue *q,
 227                         unsigned int bcount, unsigned int bsize,
 228                         enum v4l2_memory memory);
 229 int __videobuf_mmap_setup(struct videobuf_queue *q,
 230                         unsigned int bcount, unsigned int bsize,
 231                         enum v4l2_memory memory);
 232 int videobuf_mmap_free(struct videobuf_queue *q);
 233 int videobuf_mmap_mapper(struct videobuf_queue *q,
 234                          struct vm_area_struct *vma);
 235
 236 #endif