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/**
* 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 can
* access/modify the buffer here as it is still synced for
* the CPU; 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; the buffer is synced for the CPU, so drivers
* can access/modify the buffer contents; 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_QUEUED).
* 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 void *parg,
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 (*buf_finish)(struct vb2_buffer *vb);
void (*buf_cleanup)(struct vb2_buffer *vb);
int (*start_streaming)(struct vb2_queue *q, unsigned int count);
void (*stop_streaming)(struct vb2_queue *q);
void (*buf_queue)(struct vb2_buffer *vb);
};
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