blob: 8c6e825940e59c0258f9e37cf685dddd750a64ce [file] [log] [blame]
* generic helper functions for handling video4linux capture buffers
* (c) 2007 Mauro Carvalho Chehab, <>
* Highly based on video-buf written originally by:
* (c) 2001,02 Gerd Knorr <>
* (c) 2006 Mauro Carvalho Chehab, <>
* (c) 2006 Ted Walther and John Sokol
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2
#include <linux/poll.h>
#include <linux/videodev2.h>
#define UNSET (-1U)
struct videobuf_buffer;
struct videobuf_queue;
/* --------------------------------------------------------------------- */
* A small set of helper functions to manage video4linux buffers.
* struct videobuf_buffer holds the data structures used by the helper
* functions, additionally some commonly used fields for v4l buffers
* (width, height, lists, waitqueue) are in there. That struct should
* be used as first element in the drivers buffer struct.
* about the mmap helpers (videobuf_mmap_*):
* The mmaper function allows to map any subset of contingous buffers.
* This includes one mmap() call for all buffers (which the original
* video4linux API uses) as well as one mmap() for every single buffer
* (which v4l2 uses).
* If there is a valid mapping for a buffer, buffer->baddr/bsize holds
* userspace address + size which can be feeded into the
* videobuf_dma_init_user function listed above.
struct videobuf_mapping {
unsigned int count;
struct videobuf_queue *q;
enum videobuf_state {
struct videobuf_buffer {
unsigned int i;
u32 magic;
/* info about the buffer */
unsigned int width;
unsigned int height;
unsigned int bytesperline; /* use only if != 0 */
unsigned long size;
enum v4l2_field field;
enum videobuf_state state;
struct list_head stream; /* QBUF/DQBUF list */
/* touched by irq handler */
struct list_head queue;
wait_queue_head_t done;
unsigned int field_count;
struct timeval ts;
/* Memory type */
enum v4l2_memory memory;
/* buffer size */
size_t bsize;
/* buffer offset (mmap + overlay) */
size_t boff;
/* buffer addr (userland ptr!) */
unsigned long baddr;
/* for mmap'ed buffers */
struct videobuf_mapping *map;
/* Private pointer to allow specific methods to store their data */
int privsize;
void *priv;
struct videobuf_queue_ops {
int (*buf_setup)(struct videobuf_queue *q,
unsigned int *count, unsigned int *size);
int (*buf_prepare)(struct videobuf_queue *q,
struct videobuf_buffer *vb,
enum v4l2_field field);
void (*buf_queue)(struct videobuf_queue *q,
struct videobuf_buffer *vb);
void (*buf_release)(struct videobuf_queue *q,
struct videobuf_buffer *vb);
#define MAGIC_QTYPE_OPS 0x12261003
/* Helper operations - device type dependent */
struct videobuf_qtype_ops {
u32 magic;
struct videobuf_buffer *(*alloc_vb)(size_t size);
void *(*vaddr) (struct videobuf_buffer *buf);
int (*iolock) (struct videobuf_queue *q,
struct videobuf_buffer *vb,
struct v4l2_framebuffer *fbuf);
int (*sync) (struct videobuf_queue *q,
struct videobuf_buffer *buf);
int (*mmap_mapper) (struct videobuf_queue *q,
struct videobuf_buffer *buf,
struct vm_area_struct *vma);
struct videobuf_queue {
struct mutex vb_lock;
struct mutex *ext_lock;
spinlock_t *irqlock;
struct device *dev;
wait_queue_head_t wait; /* wait if queue is empty */
enum v4l2_buf_type type;
unsigned int msize;
enum v4l2_field field;
enum v4l2_field last; /* for field=V4L2_FIELD_ALTERNATE */
struct videobuf_buffer *bufs[VIDEO_MAX_FRAME];
const struct videobuf_queue_ops *ops;
struct videobuf_qtype_ops *int_ops;
unsigned int streaming:1;
unsigned int reading:1;
/* capture via mmap() + ioctl(QBUF/DQBUF) */
struct list_head stream;
/* capture via read() */
unsigned int read_off;
struct videobuf_buffer *read_buf;
/* driver private data */
void *priv_data;
static inline void videobuf_queue_lock(struct videobuf_queue *q)
if (!q->ext_lock)
static inline void videobuf_queue_unlock(struct videobuf_queue *q)
if (!q->ext_lock)
int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
int non_blocking, int intr);
int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
struct v4l2_framebuffer *fbuf);
struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q);
/* Used on videobuf-dvb */
void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
struct videobuf_buffer *buf);
void videobuf_queue_core_init(struct videobuf_queue *q,
const struct videobuf_queue_ops *ops,
struct device *dev,
spinlock_t *irqlock,
enum v4l2_buf_type type,
enum v4l2_field field,
unsigned int msize,
void *priv,
struct videobuf_qtype_ops *int_ops,
struct mutex *ext_lock);
int videobuf_queue_is_busy(struct videobuf_queue *q);
void videobuf_queue_cancel(struct videobuf_queue *q);
enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
int videobuf_reqbufs(struct videobuf_queue *q,
struct v4l2_requestbuffers *req);
int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
int videobuf_qbuf(struct videobuf_queue *q,
struct v4l2_buffer *b);
int videobuf_dqbuf(struct videobuf_queue *q,
struct v4l2_buffer *b, int nonblocking);
int videobuf_streamon(struct videobuf_queue *q);
int videobuf_streamoff(struct videobuf_queue *q);
void videobuf_stop(struct videobuf_queue *q);
int videobuf_read_start(struct videobuf_queue *q);
void videobuf_read_stop(struct videobuf_queue *q);
ssize_t videobuf_read_stream(struct videobuf_queue *q,
char __user *data, size_t count, loff_t *ppos,
int vbihack, int nonblocking);
ssize_t videobuf_read_one(struct videobuf_queue *q,
char __user *data, size_t count, loff_t *ppos,
int nonblocking);
unsigned int videobuf_poll_stream(struct file *file,
struct videobuf_queue *q,
poll_table *wait);
int videobuf_mmap_setup(struct videobuf_queue *q,
unsigned int bcount, unsigned int bsize,
enum v4l2_memory memory);
int __videobuf_mmap_setup(struct videobuf_queue *q,
unsigned int bcount, unsigned int bsize,
enum v4l2_memory memory);
int videobuf_mmap_free(struct videobuf_queue *q);
int videobuf_mmap_mapper(struct videobuf_queue *q,
struct vm_area_struct *vma);