- 根目录:
- include
- media
- videobuf2-core.h
/*
* videobuf2-core.h - V4L2 driver helper framework
*
* Copyright (C) 2010 Samsung Electronics
*
* Author: Pawel Osciak <pawel@osciak.com>
*
* 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.
*/
#ifndef _MEDIA_VIDEOBUF2_CORE_H
#define _MEDIA_VIDEOBUF2_CORE_H
#include <linux/mm_types.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/videodev2.h>
struct vb2_alloc_ctx;
struct vb2_fileio_data;
/**
* struct vb2_mem_ops - memory handling/memory allocator operations
* @alloc: allocate video memory and, optionally, allocator private data,
* return NULL on failure or a pointer to allocator private,
* per-buffer data on success; the returned private structure
* will then be passed as buf_priv argument to other ops in this
* structure
* @put: inform the allocator that the buffer will no longer be used;
* usually will result in the allocator freeing the buffer (if
* no other users of this buffer are present); the buf_priv
* argument is the allocator private per-buffer structure
* previously returned from the alloc callback
* @get_userptr: acquire userspace memory for a hardware operation; used for
* USERPTR memory types; vaddr is the address passed to the
* videobuf layer when queuing a video buffer of USERPTR type;
* should return an allocator private per-buffer structure
* associated with the buffer on success, NULL on failure;
* the returned private structure will then be passed as buf_priv
* argument to other ops in this structure
* @put_userptr: inform the allocator that a USERPTR buffer will no longer
* be used
* @vaddr: return a kernel virtual address to a given memory buffer
* associated with the passed private structure or NULL if no
* such mapping exists
* @cookie: return allocator specific cookie for a given memory buffer
* associated with the passed private structure or NULL if not
* available
* @num_users: return the current number of users of a memory buffer;
* return 1 if the videobuf layer (or actually the driver using
* it) is the only user
* @mmap: setup a userspace mapping for a given memory buffer under
* the provided virtual memory region
*
* Required ops for USERPTR types: get_userptr, put_userptr.
* Required ops for MMAP types: alloc, put, num_users, mmap.
* Required ops for read/write access types: alloc, put, num_users, vaddr
*/
struct vb2_mem_ops {
void *(*alloc)(void *alloc_ctx, unsigned long size);
void (*put)(void *buf_priv);
void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
unsigned long size, int write);
void (*put_userptr)(void *buf_priv);
void *(*vaddr)(void *buf_priv);
void *(*cookie)(void *buf_priv);
unsigned int (*num_users)(void *buf_priv);
int (*mmap)(void *buf_priv, struct vm_area_struct *vma);
};
struct vb2_plane {
void *mem_priv;
int mapped:1;
};
/**
* enum vb2_io_modes - queue access methods
* @VB2_MMAP: driver supports MMAP with streaming API
* @VB2_USERPTR: driver supports USERPTR with streaming API
* @VB2_READ: driver supports read() style access
* @VB2_WRITE: driver supports write() style access
*/
enum vb2_io_modes {
VB2_MMAP = (1 << 0),
VB2_USERPTR = (1 << 1),
VB2_READ = (1 << 2),
VB2_WRITE = (1 << 3),
};
/**
* enum vb2_fileio_flags - flags for selecting a mode of the file io emulator,
* by default the 'streaming' style is used by the file io emulator
* @VB2_FILEIO_READ_ONCE: report EOF after reading the first buffer
* @VB2_FILEIO_WRITE_IMMEDIATELY: queue buffer after each write() call
*/
enum vb2_fileio_flags {
VB2_FILEIO_READ_ONCE = (1 << 0),
VB2_FILEIO_WRITE_IMMEDIATELY = (1 << 1),
};
/**
* enum vb2_buffer_state - current video buffer state
* @VB2_BUF_STATE_DEQUEUED: buffer under userspace control
* @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver
* @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
* in a hardware operation
* @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but
* not yet dequeued to userspace
* @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
* has ended with an error, which will be reported
* to the userspace when it is dequeued
*/
enum vb2_buffer_state {
VB2_BUF_STATE_DEQUEUED,
VB2_BUF_STATE_QUEUED,
VB2_BUF_STATE_ACTIVE,
VB2_BUF_STATE_DONE,
VB2_BUF_STATE_ERROR,
};
struct vb2_queue;
/**
* struct vb2_buffer - represents a video buffer
* @v4l2_buf: struct v4l2_buffer associated with this buffer; can
* be read by the driver and relevant entries can be
* changed by the driver in case of CAPTURE types
* (such as timestamp)
* @v4l2_planes: struct v4l2_planes associated with this buffer; can
* be read by the driver and relevant entries can be
* changed by the driver in case of CAPTURE types
* (such as bytesused); NOTE that even for single-planar
* types, the v4l2_planes[0] struct should be used
* instead of v4l2_buf for filling bytesused - drivers
* should use the vb2_set_plane_payload() function for that
* @vb2_queue: the queue to which this driver belongs
* @num_planes: number of planes in the buffer
* on an internal driver queue
* @state: current buffer state; do not change
* @queued_entry: entry on the queued buffers list, which holds all
* buffers queued from userspace
* @done_entry: entry on the list that stores all buffers ready to
* be dequeued to userspace
* @planes: private per-plane information; do not change
* @num_planes_mapped: number of mapped planes; do not change
*/
struct vb2_buffer {
struct v4l2_buffer v4l2_buf;
struct v4l2_plane v4l2_planes[VIDEO_MAX_PLANES];
struct vb2_queue *vb2_queue;
unsigned int num_planes;
/* Private: internal use only */
enum vb2_buffer_state state;
struct list_head queued_entry;
struct list_head done_entry;
struct vb2_plane planes[VIDEO_MAX_PLANES];
unsigned int num_planes_mapped;
};
/**
* struct vb2_ops - driver-specific callbacks
*
* @queue_setup: called from a VIDIOC_REQBUFS handler, before
* memory allocation; driver should return the required
* number of buffers in num_buffers, the required number
* of planes per buffer in num_planes; the size of each
* plane should be set in the sizes[] array and optional
* per-plane allocator specific context in alloc_ctxs[]
* array
* @wait_prepare: release any locks taken while calling vb2 functions;
* it is called before an ioctl needs to wait for a new
* buffer to arrive; required to avoid a deadlock in
* blocking access type
* @wait_finish: reacquire all locks released in the previous callback;
* required to continue operation after sleeping while
* waiting for a new buffer to arrive
* @buf_init: called once after allocating a buffer (in MMAP case)
* or after acquiring a new USERPTR buffer; drivers may
* perform additional buffer-related initialization;
* initialization failure (return != 0) will prevent
* queue setup from completing successfully; optional
* @buf_prepare: called every time the buffer is queued from userspace;
* drivers may perform any initialization required before
* each hardware operation in this callback;
* if an error is returned, the buffer will not be queued
* in driver; optional
* @buf_finish: called before every dequeue of the buffer back to
* userspace; drivers may perform any operations required
* before userspace accesses the buffer; optional
* @buf_cleanup: called once before the buffer is freed; drivers may
* perform any additional cleanup; optional
* @start_streaming: called once before entering 'streaming' state; enables
* driver to receive buffers over buf_queue() callback
* @stop_streaming: called when 'streaming' state must be disabled; driver
* should stop any DMA transactions or wait until they
* finish and give back all buffers it got from buf_queue()
* callback; may use vb2_wait_for_all_buffers() function
* @buf_queue: passes buffer vb to the driver; driver may start
* hardware operation on this buffer; driver should give
* the buffer back by calling vb2_buffer_done() function
*/
struct vb2_ops {
int (*queue_setup)(struct vb2_queue *q, unsigned int *num_buffers,
unsigned int *num_planes, unsigned long sizes[],
void *alloc_ctxs[]);
void (*wait_prepare)(struct vb2_queue *q);
void (*wait_finish)(struct vb2_queue *q);
int (*buf_init)(struct vb2_buffer *vb);
int (*buf_prepare)(struct vb2_buffer *vb);
int (*buf_finish)(struct vb2_buffer *vb);
void (*buf_cleanup)(struct vb2_buffer *vb);
int (*start_streaming)(struct vb2_queue *q);
int (*stop_streaming)(struct vb2_queue *q);
void (*buf_queue)(struct vb2_buffer *vb);
};
/**
* struct vb2_queue - a videobuf queue
*
* @type: queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h
* @io_modes: supported io methods (see vb2_io_modes enum)
* @io_flags: additional io flags (see vb2_fileio_flags enum)
* @ops: driver-specific callbacks
* @mem_ops: memory allocator specific callbacks
* @drv_priv: driver private data
* @buf_struct_size: size of the driver-specific buffer structure;
* "0" indicates the driver doesn't want to use a custom buffer
* structure type, so sizeof(struct vb2_buffer) will is used
*
* @memory: current memory type used
* @bufs: videobuf buffer structures
* @num_buffers: number of allocated/used buffers
* @queued_list: list of buffers currently queued from userspace
* @queued_count: number of buffers owned by the driver
* @done_list: list of buffers ready to be dequeued to userspace
* @done_lock: lock to protect done_list list
* @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
* @alloc_ctx: memory type/allocator-specific contexts for each plane
* @streaming: current streaming state
* @fileio: file io emulator internal data, used only if emulator is active
*/
struct vb2_queue {
enum v4l2_buf_type type;
unsigned int io_modes;
unsigned int io_flags;
const struct vb2_ops *ops;
const struct vb2_mem_ops *mem_ops;
void *drv_priv;
unsigned int buf_struct_size;
/* private: internal use only */
enum v4l2_memory memory;
struct vb2_buffer *bufs[VIDEO_MAX_FRAME];
unsigned int num_buffers;
struct list_head queued_list;
atomic_t queued_count;
struct list_head done_list;
spinlock_t done_lock;
wait_queue_head_t done_wq;
void *alloc_ctx[VIDEO_MAX_PLANES];
unsigned int streaming:1;
struct vb2_fileio_data *fileio;
};
void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
int vb2_wait_for_all_buffers(struct vb2_queue *q);
int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
int vb2_queue_init(struct vb2_queue *q);
void vb2_queue_release(struct vb2_queue *q);
int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
loff_t *ppos, int nonblock);
size_t vb2_write(struct vb2_queue *q, char __user *data, size_t count,
loff_t *ppos, int nonblock);
/**
* vb2_is_streaming() - return streaming status of the queue
* @q: videobuf queue
*/
static inline bool vb2_is_streaming(struct vb2_queue *q)
{
return q->streaming;
}
/**
* vb2_is_busy() - return busy status of the queue
* @q: videobuf queue
*
* This function checks if queue has any buffers allocated.
*/
static inline bool vb2_is_busy(struct vb2_queue *q)
{
return (q->num_buffers > 0);
}
/**
* vb2_get_drv_priv() - return driver private data associated with the queue
* @q: videobuf queue
*/
static inline void *vb2_get_drv_priv(struct vb2_queue *q)
{
return q->drv_priv;
}
/**
* vb2_set_plane_payload() - set bytesused for the plane plane_no
* @vb: buffer for which plane payload should be set
* @plane_no: plane number for which payload should be set
* @size: payload in bytes
*/
static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
unsigned int plane_no, unsigned long size)
{
if (plane_no < vb->num_planes)
vb->v4l2_planes[plane_no].bytesused = size;
}
/**
* vb2_get_plane_payload() - get bytesused for the plane plane_no
* @vb: buffer for which plane payload should be set
* @plane_no: plane number for which payload should be set
* @size: payload in bytes
*/
static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
unsigned int plane_no)
{
if (plane_no < vb->num_planes)
return vb->v4l2_planes[plane_no].bytesused;
return 0;
}
/**
* vb2_plane_size() - return plane size in bytes
* @vb: buffer for which plane size should be returned
* @plane_no: plane number for which size should be returned
*/
static inline unsigned long
vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
{
if (plane_no < vb->num_planes)
return vb->v4l2_planes[plane_no].length;
return 0;
}
#endif /* _MEDIA_VIDEOBUF2_CORE_H */