LXR linux/include/media/videobuf-core.h

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * generic helper functions for handling video4linux capture buffers
   4 *
   5 * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org>
   6 *
   7 * Highly based on video-buf written originally by:
   8 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
   9 * (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.org>
  10 * (c) 2006 Ted Walther and John Sokol
  11 */
  12
  13#ifndef _VIDEOBUF_CORE_H
  14#define _VIDEOBUF_CORE_H
  15
  16#include <linux/poll.h>
  17#include <linux/videodev2.h>
  18
  19#define UNSET (-1U)
  20
  21
  22struct videobuf_buffer;
  23struct videobuf_queue;
  24
  25/* --------------------------------------------------------------------- */
  26
  27/*
  28 * A small set of helper functions to manage video4linux buffers.
  29 *
  30 * struct videobuf_buffer holds the data structures used by the helper
  31 * functions, additionally some commonly used fields for v4l buffers
  32 * (width, height, lists, waitqueue) are in there.  That struct should
  33 * be used as first element in the drivers buffer struct.
  34 *
  35 * about the mmap helpers (videobuf_mmap_*):
  36 *
  37 * The mmaper function allows to map any subset of contiguous buffers.
  38 * This includes one mmap() call for all buffers (which the original
  39 * video4linux API uses) as well as one mmap() for every single buffer
  40 * (which v4l2 uses).
  41 *
  42 * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
  43 * userspace address + size which can be fed into the
  44 * videobuf_dma_init_user function listed above.
  45 *
  46 */
  47
  48struct videobuf_mapping {
  49        unsigned int count;
  50        struct videobuf_queue *q;
  51};
  52
  53enum videobuf_state {
  54        VIDEOBUF_NEEDS_INIT = 0,
  55        VIDEOBUF_PREPARED   = 1,
  56        VIDEOBUF_QUEUED     = 2,
  57        VIDEOBUF_ACTIVE     = 3,
  58        VIDEOBUF_DONE       = 4,
  59        VIDEOBUF_ERROR      = 5,
  60        VIDEOBUF_IDLE       = 6,
  61};
  62
  63struct videobuf_buffer {
  64        unsigned int            i;
  65        u32                     magic;
  66
  67        /* info about the buffer */
  68        unsigned int            width;
  69        unsigned int            height;
  70        unsigned int            bytesperline; /* use only if != 0 */
  71        unsigned long           size;
  72        enum v4l2_field         field;
  73        enum videobuf_state     state;
  74        struct list_head        stream;  /* QBUF/DQBUF list */
  75
  76        /* touched by irq handler */
  77        struct list_head        queue;
  78        wait_queue_head_t       done;
  79        unsigned int            field_count;
  80        u64                     ts;
  81
  82        /* Memory type */
  83        enum v4l2_memory        memory;
  84
  85        /* buffer size */
  86        size_t                  bsize;
  87
  88        /* buffer offset (mmap + overlay) */
  89        size_t                  boff;
  90
  91        /* buffer addr (userland ptr!) */
  92        unsigned long           baddr;
  93
  94        /* for mmap'ed buffers */
  95        struct videobuf_mapping *map;
  96
  97        /* Private pointer to allow specific methods to store their data */
  98        int                     privsize;
  99        void                    *priv;
 100};
 101
 102struct videobuf_queue_ops {
 103        int (*buf_setup)(struct videobuf_queue *q,
 104                         unsigned int *count, unsigned int *size);
 105        int (*buf_prepare)(struct videobuf_queue *q,
 106                           struct videobuf_buffer *vb,
 107                           enum v4l2_field field);
 108        void (*buf_queue)(struct videobuf_queue *q,
 109                          struct videobuf_buffer *vb);
 110        void (*buf_release)(struct videobuf_queue *q,
 111                            struct videobuf_buffer *vb);
 112};
 113
 114#define MAGIC_QTYPE_OPS 0x12261003
 115
 116/* Helper operations - device type dependent */
 117struct videobuf_qtype_ops {
 118        u32                     magic;
 119
 120        struct videobuf_buffer *(*alloc_vb)(size_t size);
 121        void *(*vaddr)          (struct videobuf_buffer *buf);
 122        int (*iolock)           (struct videobuf_queue *q,
 123                                 struct videobuf_buffer *vb,
 124                                 struct v4l2_framebuffer *fbuf);
 125        int (*sync)             (struct videobuf_queue *q,
 126                                 struct videobuf_buffer *buf);
 127        int (*mmap_mapper)      (struct videobuf_queue *q,
 128                                 struct videobuf_buffer *buf,
 129                                 struct vm_area_struct *vma);
 130};
 131
 132struct videobuf_queue {
 133        struct mutex               vb_lock;
 134        struct mutex               *ext_lock;
 135        spinlock_t                 *irqlock;
 136        struct device              *dev;
 137
 138        wait_queue_head_t          wait; /* wait if queue is empty */
 139
 140        enum v4l2_buf_type         type;
 141        unsigned int               msize;
 142        enum v4l2_field            field;
 143        enum v4l2_field            last;   /* for field=V4L2_FIELD_ALTERNATE */
 144        struct videobuf_buffer     *bufs[VIDEO_MAX_FRAME];
 145        const struct videobuf_queue_ops  *ops;
 146        struct videobuf_qtype_ops  *int_ops;
 147
 148        unsigned int               streaming:1;
 149        unsigned int               reading:1;
 150
 151        /* capture via mmap() + ioctl(QBUF/DQBUF) */
 152        struct list_head           stream;
 153
 154        /* capture via read() */
 155        unsigned int               read_off;
 156        struct videobuf_buffer     *read_buf;
 157
 158        /* driver private data */
 159        void                       *priv_data;
 160};
 161
 162static inline void videobuf_queue_lock(struct videobuf_queue *q)
 163{
 164        if (!q->ext_lock)
 165                mutex_lock(&q->vb_lock);
 166}
 167
 168static inline void videobuf_queue_unlock(struct videobuf_queue *q)
 169{
 170        if (!q->ext_lock)
 171                mutex_unlock(&q->vb_lock);
 172}
 173
 174int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
 175                int non_blocking, int intr);
 176int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
 177                struct v4l2_framebuffer *fbuf);
 178
 179struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q);
 180
 181/* Used on videobuf-dvb */
 182void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
 183                              struct videobuf_buffer *buf);
 184
 185void videobuf_queue_core_init(struct videobuf_queue *q,
 186                         const struct videobuf_queue_ops *ops,
 187                         struct device *dev,
 188                         spinlock_t *irqlock,
 189                         enum v4l2_buf_type type,
 190                         enum v4l2_field field,
 191                         unsigned int msize,
 192                         void *priv,
 193                         struct videobuf_qtype_ops *int_ops,
 194                         struct mutex *ext_lock);
 195int  videobuf_queue_is_busy(struct videobuf_queue *q);
 196void videobuf_queue_cancel(struct videobuf_queue *q);
 197
 198enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 199int videobuf_reqbufs(struct videobuf_queue *q,
 200                     struct v4l2_requestbuffers *req);
 201int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 202int videobuf_qbuf(struct videobuf_queue *q,
 203                  struct v4l2_buffer *b);
 204int videobuf_dqbuf(struct videobuf_queue *q,
 205                   struct v4l2_buffer *b, int nonblocking);
 206int videobuf_streamon(struct videobuf_queue *q);
 207int videobuf_streamoff(struct videobuf_queue *q);
 208
 209void videobuf_stop(struct videobuf_queue *q);
 210
 211int videobuf_read_start(struct videobuf_queue *q);
 212void videobuf_read_stop(struct videobuf_queue *q);
 213ssize_t videobuf_read_stream(struct videobuf_queue *q,
 214                             char __user *data, size_t count, loff_t *ppos,
 215                             int vbihack, int nonblocking);
 216ssize_t videobuf_read_one(struct videobuf_queue *q,
 217                          char __user *data, size_t count, loff_t *ppos,
 218                          int nonblocking);
 219__poll_t videobuf_poll_stream(struct file *file,
 220                                  struct videobuf_queue *q,
 221                                  poll_table *wait);
 222
 223int videobuf_mmap_setup(struct videobuf_queue *q,
 224                        unsigned int bcount, unsigned int bsize,
 225                        enum v4l2_memory memory);
 226int __videobuf_mmap_setup(struct videobuf_queue *q,
 227                        unsigned int bcount, unsigned int bsize,
 228                        enum v4l2_memory memory);
 229int videobuf_mmap_free(struct videobuf_queue *q);
 230int videobuf_mmap_mapper(struct videobuf_queue *q,
 231                         struct vm_area_struct *vma);
 232
 233#endif
 234