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Release 4.12 include/media/videobuf-core.h

Directory: include/media
 * 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 contiguous 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 {
VIDEOBUF_DONE       = 4,
VIDEOBUF_IDLE       = 6,

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) mutex_lock(&q->vb_lock); }


Hans Verkuil27100.00%1100.00%

static inline void videobuf_queue_unlock(struct videobuf_queue *q) { if (!q->ext_lock) mutex_unlock(&q->vb_lock); }


Hans Verkuil27100.00%1100.00%

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); #endif

Overall Contributors

Mauro Carvalho Chehab73884.15%523.81%
Hans Verkuil809.12%733.33%
Brandon Philips293.31%419.05%
Arjan van de Ven212.39%14.76%
Guennadi Liakhovetski40.46%14.76%
Pawel Osciak20.23%14.76%
Jonathan Corbet20.23%14.76%
Masahiro Yamada10.11%14.76%
Directory: include/media
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