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/*
* 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>
#include <linux/dma-buf.h>
struct vb2_alloc_ctx;
struct vb2_fileio_data;
struct vb2_threadio_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. Additional gfp_flags to use when allocating the
* are also passed to this operation. These flags are from the
* gfp_flags field of vb2_queue.
* @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.
* @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
* used for DMABUF memory types; alloc_ctx is the alloc context
* dbuf is the shared dma_buf; returns NULL on failure;
* allocator private per-buffer structure on success;
* this needs to be used for further accesses to the buffer.
* @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
* buffer is no longer used; the buf_priv argument is the
* allocator private per-buffer structure previously returned
* from the attach_dmabuf callback.
* @map_dmabuf: request for access to the dmabuf from allocator; the allocator
* of dmabuf is informed that this driver is going to use the
* dmabuf.
* @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
* that this driver is done using the dmabuf for now.
* @prepare: called every time the buffer is passed from userspace to the
* driver, useful for cache synchronisation, optional.
* @finish: called every time the buffer is passed back from the driver
* to the userspace, also optional.
* @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.
* Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf,
* unmap_dmabuf.
*/
struct vb2_mem_ops {
void *(*alloc)(void *alloc_ctx, unsigned long size, gfp_t gfp_flags);
void (*put)(void *buf_priv);
struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
unsigned long size, int write);
void (*put_userptr)(void *buf_priv);
void (*prepare)(void *buf_priv);
void (*finish)(void *buf_priv);
void *(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf,
unsigned long size, int write);
void (*detach_dmabuf)(void *buf_priv);
int (*map_dmabuf)(void *buf_priv);
void (*unmap_dmabuf)(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;
struct dma_buf *dbuf;
unsigned int dbuf_mapped;
};
/**
* 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
* @VB2_DMABUF: driver supports DMABUF with streaming API
*/
enum vb2_io_modes {
VB2_MMAP = (1 << 0),
VB2_USERPTR = (1 << 1),
VB2_READ = (1 << 2),
VB2_WRITE = (1 << 3),
VB2_DMABUF = (1 << 4),
};
/**
* 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_PREPARING: buffer is being prepared in videobuf
* @VB2_BUF_STATE_PREPARED: buffer prepared in videobuf and by the driver
* @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_PREPARING,
VB2_BUF_STATE_PREPARED,
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
*/
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];
#ifdef CONFIG_VIDEO_ADV_DEBUG
/*
* Counters for how often these buffer-related ops are
* called. Used to check for unbalanced ops.
*/
u32 cnt_mem_alloc;
u32 cnt_mem_put;
u32 cnt_mem_get_dmabuf;
u32 cnt_mem_get_userptr;
u32 cnt_mem_put_userptr;
u32 cnt_mem_prepare;
u32 cnt_mem_finish;
u32 cnt_mem_attach_dmabuf;
u32 cnt_mem_detach_dmabuf;
u32 cnt_mem_map_dmabuf;
u32 cnt_mem_unmap_dmabuf;
u32 cnt_mem_vaddr;
u32 cnt_mem_cookie;
u32 cnt_mem_num_users;
u32 cnt_mem_mmap;
u32 cnt_buf_init;
u32 cnt_buf_prepare;
u32 cnt_buf_finish;
u32 cnt_buf_cleanup;
u32 cnt_buf_queue;
/* This counts the number of calls to vb2_buffer_done() */
u32 cnt_buf_done;
#endif
};
/**
* struct vb2_ops - driver-specific callbacks
*
* @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS
* handlers before memory allocation, or, if
* *num_planes != 0, after the allocation to verify a
* smaller number of buffers. 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 the
* alloc_ctxs[] array. When called from VIDIOC_REQBUFS,
* fmt == NULL, the driver has to use the currently
* configured format and *num_buffers is the total number
* of buffers, that are being allocated. When called from
* VIDIOC_CREATE_BUFS, fmt != NULL and it describes the
* target frame format (if the format isn't valid the
* callback must return -EINVAL). In this case *num_buffers
* are being allocated additionally to q->num_buffers.
* @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
* and from the VIDIOC_PREPARE_BUF ioctl; drivers may
* perform any initialization required before each hardware
* operation in this callback; drivers that support
* VIDIOC_CREATE_BUFS must also validate the buffer size;
* 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. The
* buffer state can be one of the following: DONE and
* ERROR occur while streaming is in progress, and the
* PREPARED state occurs when the queue has been canceled
* and all pending buffers are being returned to their
* default DEQUEUED state. Typically you only have to do
* something if the state is VB2_BUF_STATE_DONE, since in
* all other cases the buffer contents will be ignored
* anyway.
* @buf_cleanup: called once before the buffer is freed; drivers may
* perform any additional cleanup; optional.
* @start_streaming: called once to enter 'streaming' state; the driver may
* receive buffers with @buf_queue callback before
* @start_streaming is called; the driver gets the number
* of already queued buffers in count parameter; driver
* can return an error if hardware fails, in that case all
* buffers that have been already given by the @buf_queue
* callback are to be returned by the driver by calling
* @vb2_buffer_done(VB2_BUF_STATE_DEQUEUED).
* If you need a minimum number of buffers before you can
* start streaming, then set @min_buffers_needed in the
* vb2_queue structure. If that is non-zero then
* start_streaming won't be called until at least that
* many buffers have been queued up by userspace.
* @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 by calling @vb2_buffer_done() with either
* VB2_BUF_STATE_DONE or VB2_BUF_STATE_ERROR; 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;
* it is allways called after calling STREAMON ioctl;
* might be called before start_streaming callback if user
* pre-queued buffers before calling STREAMON.
*/
struct vb2_ops {
int (*queue_setup)(struct vb2_queue *q, const struct v4l2_format *fmt,
unsigned int *num_buffers, unsigned int *num_planes,
unsigned int 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);
void
|