Edit File: 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> #include <linux/dma-buf.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. 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); 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_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_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]; }; /** * 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. 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; 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 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 or not enough * buffers has been queued, in such case all buffers that * have been already given by the @buf_queue callback are * invalidated. * @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; * 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); int (*buf_finish)(struct vb2_buffer *vb); void (*buf_cleanup)(struct vb2_buffer *vb); int (*start_streaming)(struct vb2_queue *q, unsigned int count); int (*stop_streaming)(struct vb2_queue *q); void (*buf_queue)(struct vb2_buffer *vb); }; struct v4l2_fh; /** * 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) * @lock: pointer to a mutex that protects the vb2_queue struct. The * driver can set this to a mutex to let the v4l2 core serialize * the queuing ioctls. If the driver wants to handle locking * itself, then this should be set to NULL. This lock is not used * by the videobuf2 core API. * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle * that called reqbufs, create_buffers or started fileio. * This field is not used by the videobuf2 core API, but it allows * drivers to easily associate an owner filehandle with the queue. * @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 * @gfp_flags: additional gfp flags used when allocating the buffers. * Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32 * to force the buffer allocation to a specific memory zone. * * @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; struct mutex *lock; struct v4l2_fh *owner; const struct vb2_ops *ops; const struct vb2_mem_ops *mem_ops; void *drv_priv; unsigned int buf_struct_size; u32 timestamp_type; gfp_t gfp_flags; /* 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 plane_sizes[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_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b); int __must_check 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_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb); 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); #ifndef CONFIG_MMU unsigned long vb2_get_unmapped_area(struct vb2_queue *q, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); #endif 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; } /* * The following functions are not part of the vb2 core API, but are simple * helper functions that you can use in your struct v4l2_file_operations, * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock * or video_device->lock is set, and they will set and test vb2_queue->owner * to check if the calling filehandle is permitted to do the queuing operation. */ /* struct v4l2_ioctl_ops helpers */ int vb2_ioctl_reqbufs(struct file *file, void *priv, struct v4l2_requestbuffers *p); int vb2_ioctl_create_bufs(struct file *file, void *priv, struct v4l2_create_buffers *p); int vb2_ioctl_prepare_buf(struct file *file, void *priv, struct v4l2_buffer *p); int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p); int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p); int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p); int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i); int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i); int vb2_ioctl_expbuf(struct file *file, void *priv, struct v4l2_exportbuffer *p); /* struct v4l2_file_operations helpers */ int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma); int vb2_fop_release(struct file *file); ssize_t vb2_fop_write(struct file *file, char __user *buf, size_t count, loff_t *ppos); ssize_t vb2_fop_read(struct file *file, char __user *buf, size_t count, loff_t *ppos); unsigned int vb2_fop_poll(struct file *file, poll_table *wait); #ifndef CONFIG_MMU unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); #endif /* struct vb2_ops helpers, only use if vq->lock is non-NULL. */ void vb2_ops_wait_prepare(struct vb2_queue *vq); void vb2_ops_wait_finish(struct vb2_queue *vq); #endif /* _MEDIA_VIDEOBUF2_CORE_H */