diff options
Diffstat (limited to 'include/media/videobuf2-core.h')
| -rw-r--r-- | include/media/videobuf2-core.h | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index b6546db..68f93da 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -536,35 +536,274 @@ struct vb2_queue { #endif }; +/** + * vb2_plane_vaddr() - Return a kernel virtual address of a given plane + * @vb: vb2_buffer to which the plane in question belongs to + * @plane_no: plane number for which the address is to be returned + * + * This function returns a kernel virtual address of a given plane if + * such a mapping exist, NULL otherwise. + */ void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no); + +/** + * vb2_plane_cookie() - Return allocator specific cookie for the given plane + * @vb: vb2_buffer to which the plane in question belongs to + * @plane_no: plane number for which the cookie is to be returned + * + * This function returns an allocator specific cookie for a given plane if + * available, NULL otherwise. The allocator should provide some simple static + * inline function, which would convert this cookie to the allocator specific + * type that can be used directly by the driver to access the buffer. This can + * be for example physical address, pointer to scatter list or IOMMU mapping. + */ void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no); +/** + * vb2_buffer_done() - inform videobuf that an operation on a buffer is finished + * @vb: vb2_buffer returned from the driver + * @state: either %VB2_BUF_STATE_DONE if the operation finished successfully, + * %VB2_BUF_STATE_ERROR if the operation finished with an error or + * %VB2_BUF_STATE_QUEUED if the driver wants to requeue buffers. + * If start_streaming fails then it should return buffers with state + * %VB2_BUF_STATE_QUEUED to put them back into the queue. + * + * This function should be called by the driver after a hardware operation on + * a buffer is finished and the buffer may be returned to userspace. The driver + * cannot use this buffer anymore until it is queued back to it by videobuf + * by the means of buf_queue callback. Only buffers previously queued to the + * driver by buf_queue can be passed to this function. + * + * While streaming a buffer can only be returned in state DONE or ERROR. + * The start_streaming op can also return them in case the DMA engine cannot + * be started for some reason. In that case the buffers should be returned with + * state QUEUED. + */ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state); + +/** + * vb2_discard_done() - discard all buffers marked as DONE + * @q: videobuf2 queue + * + * This function is intended to be used with suspend/resume operations. It + * discards all 'done' buffers as they would be too old to be requested after + * resume. + * + * Drivers must stop the hardware and synchronize with interrupt handlers and/or + * delayed works before calling this function to make sure no buffer will be + * touched by the driver and/or hardware. + */ void vb2_discard_done(struct vb2_queue *q); + +/** + * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2 + * @q: videobuf2 queue + * + * This function will wait until all buffers that have been given to the driver + * by buf_queue() are given back to vb2 with vb2_buffer_done(). It doesn't call + * wait_prepare, wait_finish pair. It is intended to be called with all locks + * taken, for example from stop_streaming() callback. + */ int vb2_wait_for_all_buffers(struct vb2_queue *q); +/** + * vb2_core_querybuf() - query video buffer information + * @q: videobuf queue + * @index: id number of the buffer + * @pb: buffer struct passed from userspace + * + * Should be called from vidioc_querybuf ioctl handler in driver. + * The passed buffer should have been verified. + * This function fills the relevant information for the userspace. + */ void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb); + +/** + * vb2_core_reqbufs() - Initiate streaming + * @q: videobuf2 queue + * @memory: memory type + * @count: requested buffer count + * + * Should be called from vidioc_reqbufs ioctl handler of a driver. + * This function: + * 1) verifies streaming parameters passed from the userspace, + * 2) sets up the queue, + * 3) negotiates number of buffers and planes per buffer with the driver + * to be used during streaming, + * 4) allocates internal buffer structures (struct vb2_buffer), according to + * the agreed parameters, + * 5) for MMAP memory type, allocates actual video memory, using the + * memory handling/allocation routines provided during queue initialization + * + * If req->count is 0, all the memory will be freed instead. + * If the queue has been allocated previously (by a previous vb2_reqbufs) call + * and the queue is not busy, memory will be reallocated. + * + * The return values from this function are intended to be directly returned + * from vidioc_reqbufs handler in driver. + */ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, unsigned int *count); + +/** + * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs + * @q: videobuf2 queue + * @memory: memory type + * @count: requested buffer count + * @parg: parameter passed to device driver + * + * Should be called from vidioc_create_bufs ioctl handler of a driver. + * This function: + * 1) verifies parameter sanity + * 2) calls the .queue_setup() queue operation + * 3) performs any necessary memory allocations + * + * The return values from this function are intended to be directly returned + * from vidioc_create_bufs handler in driver. + */ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory, unsigned int *count, unsigned requested_planes, const unsigned int requested_sizes[]); + +/** + * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace + * to the kernel + * @q: videobuf2 queue + * @index: id number of the buffer + * @pb: buffer structure passed from userspace to vidioc_prepare_buf + * handler in driver + * + * Should be called from vidioc_prepare_buf ioctl handler of a driver. + * The passed buffer should have been verified. + * This function 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_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb); + +/** + * vb2_core_qbuf() - Queue a buffer from userspace + * @q: videobuf2 queue + * @index: id number of the buffer + * @pb: buffer structure passed from userspace to vidioc_qbuf handler + * in driver + * + * Should be called from vidioc_qbuf ioctl handler of a driver. + * The passed buffer should have been verified. + * This function: + * 1) if necessary, calls buf_prepare callback in the driver (if provided), in + * which driver-specific buffer initialization can be performed, + * 2) 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_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb); + +/** + * vb2_core_dqbuf() - Dequeue a buffer to the userspace + * @q: videobuf2 queue + * @pindex: pointer to the buffer index. May be NULL + * @pb: 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. + * The passed buffer should have been verified. + * This function: + * 1) 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, + * 2) 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_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb, bool nonblocking); int vb2_core_streamon(struct vb2_queue *q, unsigned int type); int vb2_core_streamoff(struct vb2_queue *q, unsigned int type); +/** + * vb2_core_expbuf() - Export a buffer as a file descriptor + * @q: videobuf2 queue + * @fd: file descriptor associated with DMABUF (set by driver) * + * @type: buffer type + * @index: id number of the buffer + * @plane: index of the plane to be exported, 0 for single plane queues + * @flags: flags for newly created file, currently only O_CLOEXEC is + * supported, refer to manual of open syscall for more details + * + * The return values from this function are intended to be directly returned + * from vidioc_expbuf handler in driver. + */ int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type, unsigned int index, unsigned int plane, unsigned int flags); +/** + * vb2_core_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 vb2_core_queue_init(struct vb2_queue *q); + +/** + * vb2_core_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_core_queue_release(struct vb2_queue *q); +/** + * vb2_queue_error() - signal a fatal error on the queue + * @q: videobuf2 queue + * + * Flag that a fatal unrecoverable error has occurred and wake up all processes + * waiting on the queue. Polling will now set POLLERR and queuing and dequeuing + * buffers will return -EIO. + * + * The error flag will be cleared when cancelling the queue, either from + * vb2_streamoff or vb2_queue_release. Drivers should thus not call this + * function before starting the stream, otherwise the error flag will remain set + * until the queue is released when closing the device node. + */ void vb2_queue_error(struct vb2_queue *q); +/** + * vb2_mmap() - map video buffers into application address space + * @q: videobuf2 queue + * @vma: vma passed to the mmap file operation handler in the driver + * + * Should be called from mmap file operation handler of a driver. + * This function maps one plane of one of the available video buffers to + * userspace. To map whole video memory allocated on reqbufs, this function + * has to be called once per each plane per each buffer previously allocated. + * + * When the userspace application calls mmap, it passes to it an offset returned + * to it earlier by the means of vidioc_querybuf handler. That offset acts as + * a "cookie", which is then used to identify the plane to be mapped. + * This function finds a plane with a matching offset and a mapping is performed + * by the means of a provided memory operation. + * + * The return values from this function are intended to be directly returned + * from the mmap handler in driver. + */ 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, @@ -573,6 +812,23 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, unsigned long pgoff, unsigned long flags); #endif + +/** + * vb2_core_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. + * + * The return values from this function are intended to be directly returned + * from poll handler in driver. + */ unsigned int vb2_core_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, @@ -717,7 +973,20 @@ static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q) * The following functions are not part of the vb2 core API, but are useful * functions for videobuf2-*. */ + +/** + * vb2_buffer_in_use() - return true if the buffer is in use and + * the queue cannot be freed (by the means of REQBUFS(0)) call + * + * @vb: buffer for which plane size should be returned + * @q: videobuf queue + */ bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb); + +/** + * vb2_verify_memory_type() - Check whether the memory type and buffer type + * passed to a buffer operation are compatible with the queue. + */ int vb2_verify_memory_type(struct vb2_queue *q, enum vb2_memory memory, unsigned int type); #endif /* _MEDIA_VIDEOBUF2_CORE_H */ |
