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[linux-2.6.git] / 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 */