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
  22 struct videobuf_buffer;
  23 struct 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
  48 struct videobuf_mapping {
  49         unsigned int count;
  50         struct videobuf_queue *q;
  51 };
  52
  53 enum 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
  63 struct 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
 102 struct 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 */
 117 struct 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
 132 struct 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
 162 static inline void videobuf_queue_lock(struct videobuf_queue *q)
 163 {
 164         if (!q->ext_lock)
 165                 mutex_lock(&q->vb_lock);
 166 }
 167
 168 static inline void videobuf_queue_unlock(struct videobuf_queue *q)
 169 {
 170         if (!q->ext_lock)
 171                 mutex_unlock(&q->vb_lock);
 172 }
 173
 174 int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
 175                 int non_blocking, int intr);
 176 int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
 177                 struct v4l2_framebuffer *fbuf);
 178
 179 struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q);
 180
 181 /* Used on videobuf-dvb */
 182 void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
 183                               struct videobuf_buffer *buf);
 184
 185 void 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);
 195 int  videobuf_queue_is_busy(struct videobuf_queue *q);
 196 void videobuf_queue_cancel(struct videobuf_queue *q);
 197
 198 enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
 199 int videobuf_reqbufs(struct videobuf_queue *q,
 200                      struct v4l2_requestbuffers *req);
 201 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
 202 int videobuf_qbuf(struct videobuf_queue *q,
 203                   struct v4l2_buffer *b);
 204 int videobuf_dqbuf(struct videobuf_queue *q,
 205                    struct v4l2_buffer *b, int nonblocking);
 206 int videobuf_streamon(struct videobuf_queue *q);
 207 int videobuf_streamoff(struct videobuf_queue *q);
 208
 209 void videobuf_stop(struct videobuf_queue *q);
 210
 211 int videobuf_read_start(struct videobuf_queue *q);
 212 void videobuf_read_stop(struct videobuf_queue *q);
 213 ssize_t videobuf_read_stream(struct videobuf_queue *q,
 214                              char __user *data, size_t count, loff_t *ppos,
 215                              int vbihack, int nonblocking);
 216 ssize_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
 223 int videobuf_mmap_setup(struct videobuf_queue *q,
 224                         unsigned int bcount, unsigned int bsize,
 225                         enum v4l2_memory memory);
 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_free(struct videobuf_queue *q);
 230 int videobuf_mmap_mapper(struct videobuf_queue *q,
 231                          struct vm_area_struct *vma);
 232
 233 #endif