diff options
Diffstat (limited to 'include/media/videobuf2-v4l2.h')
| -rw-r--r-- | include/media/videobuf2-v4l2.h | 182 |
1 files changed, 179 insertions, 3 deletions
diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h index 3cc836f76675..036127c54bbf 100644 --- a/include/media/videobuf2-v4l2.h +++ b/include/media/videobuf2-v4l2.h @@ -25,11 +25,13 @@ /** * struct vb2_v4l2_buffer - video buffer information for v4l2 + * * @vb2_buf: video buffer 2 * @flags: buffer informational flags * @field: enum v4l2_field; field order of the image in the buffer * @timecode: frame timecode * @sequence: sequence count of this frame + * * Should contain enough information to be able to cover all the fields * of struct v4l2_buffer at videodev2.h */ @@ -49,22 +51,183 @@ struct vb2_v4l2_buffer { container_of(vb, struct vb2_v4l2_buffer, vb2_buf) int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b); + +/** + * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies + * the memory and type values. + * + * @q: videobuf2 queue + * @req: struct passed from userspace to vidioc_reqbufs handler + * in driver + */ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); +/** + * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies + * the memory and type values. + * + * @q: videobuf2 queue + * @create: creation parameters, passed from userspace to vidioc_create_bufs + * handler in driver + */ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); + +/** + * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel + * + * @q: videobuf2 queue + * @b: buffer structure passed from userspace to vidioc_prepare_buf + * handler in driver + * + * Should be called from vidioc_prepare_buf ioctl handler of a driver. + * This function: + * + * #) verifies the passed buffer, + * #) calls buf_prepare callback in the driver (if provided), in which + * driver-specific buffer initialization can be performed. + * + * The return values from this function are intended to be directly returned + * from vidioc_prepare_buf handler in driver. + */ int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b); +/** + * vb2_qbuf() - Queue a buffer from userspace + * @q: videobuf2 queue + * @b: buffer structure passed from userspace to VIDIOC_QBUF() handler + * in driver + * + * Should be called from VIDIOC_QBUF() ioctl handler of a driver. + * + * This function: + * + * #) verifies the passed buffer, + * #) if necessary, calls buf_prepare callback in the driver (if provided), in + * which driver-specific buffer initialization can be performed, + * #) if streaming is on, queues the buffer in driver by the means of buf_queue + * callback for processing. + * + * The return values from this function are intended to be directly returned + * from VIDIOC_QBUF() handler in driver. + */ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b); + +/** + * vb2_expbuf() - Export a buffer as a file descriptor + * @q: videobuf2 queue + * @eb: export buffer structure passed from userspace to VIDIOC_EXPBUF() + * handler in driver + * + * The return values from this function are intended to be directly returned + * from VIDIOC_EXPBUF() handler in driver. + */ int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb); + +/** + * vb2_dqbuf() - Dequeue a buffer to the userspace + * @q: videobuf2 queue + * @b: buffer structure passed from userspace to VIDIOC_DQBUF() handler + * in driver + * @nonblocking: if true, this call will not sleep waiting for a buffer if no + * buffers ready for dequeuing are present. Normally the driver + * would be passing (file->f_flags & O_NONBLOCK) here + * + * Should be called from VIDIOC_DQBUF() ioctl handler of a driver. + * + * This function: + * + * #) verifies the passed buffer, + * #) calls buf_finish callback in the driver (if provided), in which + * driver can perform any additional operations that may be required before + * returning the buffer to userspace, such as cache sync, + * #) the buffer struct members are filled with relevant information for + * the userspace. + * + * The return values from this function are intended to be directly returned + * from VIDIOC_DQBUF() handler in driver. + */ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); +/** + * vb2_streamon - start streaming + * @q: videobuf2 queue + * @type: type argument passed from userspace to vidioc_streamon handler + * + * Should be called from vidioc_streamon handler of a driver. + * + * This function: + * + * 1) verifies current state + * 2) passes any previously queued buffers to the driver and starts streaming + * + * The return values from this function are intended to be directly returned + * from vidioc_streamon handler in the driver. + */ int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type); + +/** + * vb2_streamoff - stop streaming + * @q: videobuf2 queue + * @type: type argument passed from userspace to vidioc_streamoff handler + * + * Should be called from vidioc_streamoff handler of a driver. + * + * This function: + * + * #) verifies current state, + * #) stop streaming and dequeues any queued buffers, including those previously + * passed to the driver (after waiting for the driver to finish). + * + * This call can be used for pausing playback. + * The return values from this function are intended to be directly returned + * from vidioc_streamoff handler in the driver + */ int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type); +/** + * vb2_queue_init() - initialize a videobuf2 queue + * @q: videobuf2 queue; this structure should be allocated in driver + * + * The vb2_queue structure should be allocated by the driver. The driver is + * responsible of clearing it's content and setting initial values for some + * required entries before calling this function. + * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer + * to the struct vb2_queue description in include/media/videobuf2-core.h + * for more information. + */ int __must_check vb2_queue_init(struct vb2_queue *q); + +/** + * vb2_queue_release() - stop streaming, release the queue and free memory + * @q: videobuf2 queue + * + * This function stops streaming and performs necessary clean ups, including + * freeing video buffer memory. The driver is responsible for freeing + * the vb2_queue structure itself. + */ void vb2_queue_release(struct vb2_queue *q); + +/** + * vb2_poll() - implements poll userspace operation + * @q: videobuf2 queue + * @file: file argument passed to the poll file operation handler + * @wait: wait argument passed to the poll file operation handler + * + * This function implements poll file operation handler for a driver. + * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will + * be informed that the file descriptor of a video device is available for + * reading. + * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor + * will be reported as available for writing. + * + * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any + * pending events. + * + * The return values from this function are intended to be directly returned + * from poll handler in driver. + */ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, - poll_table *wait); + poll_table *wait); /* * The following functions are not part of the vb2 core API, but are simple @@ -105,9 +268,22 @@ 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. */ - +/** + * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue + * + * @vq: pointer to struct vb2_queue + * + * ..note:: only use if vq->lock is non-NULL. + */ void vb2_ops_wait_prepare(struct vb2_queue *vq); + +/** + * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue + * + * @vq: pointer to struct vb2_queue + * + * ..note:: only use if vq->lock is non-NULL. + */ void vb2_ops_wait_finish(struct vb2_queue *vq); #endif /* _MEDIA_VIDEOBUF2_V4L2_H */ |