diff options
Diffstat (limited to 'include/media/videobuf2-core.h')
| -rw-r--r-- | include/media/videobuf2-core.h | 519 |
1 files changed, 306 insertions, 213 deletions
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index e55efc62a950..aa16c064294f 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -16,6 +16,7 @@ #include <linux/mutex.h> #include <linux/poll.h> #include <linux/dma-buf.h> +#include <linux/bitops.h> #define VB2_MAX_FRAME (32) #define VB2_MAX_PLANES (8) @@ -45,7 +46,7 @@ struct vb2_fileio_data; struct vb2_threadio_data; /** - * struct vb2_mem_ops - memory handling/memory allocator operations + * struct vb2_mem_ops - memory handling/memory allocator operations. * @alloc: allocate video memory and, optionally, allocator private data, * return ERR_PTR() on failure or a pointer to allocator private, * per-buffer data on success; the returned private structure @@ -69,7 +70,7 @@ struct vb2_threadio_data; * 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; + * @attach_dmabuf: attach a shared &struct dma_buf for a hardware operation; * used for DMABUF memory types; dev is the alloc device * dbuf is the shared dma_buf; returns ERR_PTR() on failure; * allocator private per-buffer structure on success; @@ -145,28 +146,28 @@ struct vb2_mem_ops { }; /** - * struct vb2_plane - plane information - * @mem_priv: private data with this plane - * @dbuf: dma_buf - shared buffer object + * struct vb2_plane - plane information. + * @mem_priv: private data with this plane. + * @dbuf: dma_buf - shared buffer object. * @dbuf_mapped: flag to show whether dbuf is mapped or not - * @bytesused: number of bytes occupied by data in the plane (payload) - * @length: size of this plane (NOT the payload) in bytes + * @bytesused: number of bytes occupied by data in the plane (payload). + * @length: size of this plane (NOT the payload) in bytes. * @min_length: minimum required size of this plane (NOT the payload) in bytes. * @length is always greater or equal to @min_length. - * @offset: when memory in the associated struct vb2_buffer is - * VB2_MEMORY_MMAP, equals the offset from the start of + * @m: Union with memtype-specific data. + * @m.offset: when memory in the associated struct vb2_buffer is + * %VB2_MEMORY_MMAP, equals the offset from the start of * the device memory for this plane (or is a "cookie" that - * should be passed to mmap() called on the video node) - * @userptr: when memory is VB2_MEMORY_USERPTR, a userspace pointer - * pointing to this plane - * @fd: when memory is VB2_MEMORY_DMABUF, a userspace file - * descriptor associated with this plane - * @m: Union with memtype-specific data (@offset, @userptr or - * @fd). + * should be passed to mmap() called on the video node). + * @m.userptr: when memory is %VB2_MEMORY_USERPTR, a userspace pointer + * pointing to this plane. + * @m.fd: when memory is %VB2_MEMORY_DMABUF, a userspace file + * descriptor associated with this plane. * @data_offset: offset in the plane to the start of data; usually 0, - * unless there is a header in front of the data + * unless there is a header in front of the data. + * * Should contain enough information to be able to cover all the fields - * of struct v4l2_plane at videodev2.h + * of &struct v4l2_plane at videodev2.h. */ struct vb2_plane { void *mem_priv; @@ -184,35 +185,35 @@ struct vb2_plane { }; /** - * 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 - 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), + VB2_MMAP = BIT(0), + VB2_USERPTR = BIT(1), + VB2_READ = BIT(2), + VB2_WRITE = BIT(3), + VB2_DMABUF = BIT(4), }; /** - * enum vb2_buffer_state - current video buffer state - * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control - * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf - * @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_REQUEUEING: re-queue a buffer to the driver + * enum vb2_buffer_state - current video buffer state. + * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control. + * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf. + * @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_REQUEUEING: re-queue a buffer to the driver. * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used - * in a hardware operation + * in a hardware operation. * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but - * not yet dequeued to userspace + * 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 + * to the userspace when it is dequeued. */ enum vb2_buffer_state { VB2_BUF_STATE_DEQUEUED, @@ -228,15 +229,15 @@ enum vb2_buffer_state { struct vb2_queue; /** - * struct vb2_buffer - represents a video buffer - * @vb2_queue: the queue to which this driver belongs - * @index: id number of the buffer - * @type: buffer type - * @memory: the method, in which the actual data is passed + * struct vb2_buffer - represents a video buffer. + * @vb2_queue: pointer to &struct vb2_queue with the queue to + * which this driver belongs. + * @index: id number of the buffer. + * @type: buffer type. + * @memory: the method, in which the actual data is passed. * @num_planes: number of planes in the buffer - * on an internal driver queue - * @planes: private per-plane information; do not change - * @timestamp: frame timestamp in ns + * on an internal driver queue. + * @timestamp: frame timestamp in ns. */ struct vb2_buffer { struct vb2_queue *vb2_queue; @@ -244,7 +245,6 @@ struct vb2_buffer { unsigned int type; unsigned int memory; unsigned int num_planes; - struct vb2_plane planes[VB2_MAX_PLANES]; u64 timestamp; /* private: internal use only @@ -254,9 +254,11 @@ struct vb2_buffer { * all buffers queued from userspace * done_entry: entry on the list that stores all buffers ready * to be dequeued to userspace + * vb2_plane: per-plane information; do not change */ enum vb2_buffer_state state; + struct vb2_plane planes[VB2_MAX_PLANES]; struct list_head queued_entry; struct list_head done_entry; #ifdef CONFIG_VIDEO_ADV_DEBUG @@ -292,7 +294,7 @@ struct vb2_buffer { }; /** - * struct vb2_ops - driver-specific callbacks + * struct vb2_ops - driver-specific callbacks. * * @queue_setup: called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS() * handlers before memory allocation. It can be called @@ -358,8 +360,8 @@ struct vb2_buffer { * the @buf_queue callback are to be returned by the driver * by calling vb2_buffer_done() with %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, then set + * &vb2_queue->min_buffers_needed. 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 @@ -396,18 +398,18 @@ struct vb2_ops { }; /** - * struct vb2_buf_ops - driver-specific callbacks + * struct vb2_buf_ops - driver-specific callbacks. * * @verify_planes_array: Verify that a given user space structure contains * enough planes for the buffer. This is called * for each dequeued buffer. - * @fill_user_buffer: given a vb2_buffer fill in the userspace structure. - * For V4L2 this is a struct v4l2_buffer. - * @fill_vb2_buffer: given a userspace structure, fill in the vb2_buffer. + * @fill_user_buffer: given a &vb2_buffer fill in the userspace structure. + * For V4L2 this is a &struct v4l2_buffer. + * @fill_vb2_buffer: given a userspace structure, fill in the &vb2_buffer. * If the userspace structure is invalid, then this op * will return an error. * @copy_timestamp: copy the timestamp from a userspace structure to - * the vb2_buffer struct. + * the &struct vb2_buffer. */ struct vb2_buf_ops { int (*verify_planes_array)(struct vb2_buffer *vb, const void *pb); @@ -418,20 +420,21 @@ struct vb2_buf_ops { }; /** - * struct vb2_queue - a videobuf queue + * struct vb2_queue - a videobuf queue. * * @type: private buffer type whose content is defined by the vb2-core * caller. For example, for V4L2, it should match - * the types defined on enum &v4l2_buf_type - * @io_modes: supported io methods (see vb2_io_modes enum) + * the types defined on &enum v4l2_buf_type. + * @io_modes: supported io methods (see &enum vb2_io_modes). + * @alloc_devs: &struct device memory type/allocator-specific per-plane device * @dev: device to use for the default allocation context if the driver * doesn't fill in the @alloc_devs array. * @dma_attrs: DMA attributes to use for the DMA. * @bidirectional: when this flag is set the DMA direction for the buffers of - * this queue will be overridden with DMA_BIDIRECTIONAL direction. + * this queue will be overridden with %DMA_BIDIRECTIONAL direction. * This is useful in cases where the hardware (firmware) writes to - * a buffer which is mapped as read (DMA_TO_DEVICE), or reads from - * buffer which is mapped for write (DMA_FROM_DEVICE) in order + * a buffer which is mapped as read (%DMA_TO_DEVICE), or reads from + * buffer which is mapped for write (%DMA_FROM_DEVICE) in order * to satisfy some internal hardware restrictions or adds a padding * needed by the processing algorithm. In case the DMA mapping is * not bidirectional but the hardware (firmware) trying to access @@ -440,10 +443,10 @@ struct vb2_buf_ops { * @fileio_read_once: report EOF after reading the first buffer * @fileio_write_immediately: queue buffer after each write() call * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver - * @quirk_poll_must_check_waiting_for_buffers: Return POLLERR at poll when QBUF + * @quirk_poll_must_check_waiting_for_buffers: Return %POLLERR at poll when QBUF * has not been called. This is a vb1 idiom that has been adopted * also by vb2. - * @lock: pointer to a mutex that protects the vb2_queue struct. The + * @lock: pointer to a mutex that protects the &struct vb2_queue. 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 @@ -454,17 +457,17 @@ struct vb2_buf_ops { * drivers to easily associate an owner filehandle with the queue. * @ops: driver-specific callbacks * @mem_ops: memory allocator specific callbacks - * @buf_ops: callbacks to deliver buffer information - * between user-space and kernel-space - * @drv_priv: driver private data + * @buf_ops: callbacks to deliver buffer information. + * between user-space and kernel-space. + * @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. for example, sizeof(struct vb2_v4l2_buffer) + * structure type. for example, ``sizeof(struct vb2_v4l2_buffer)`` * will be used for v4l2. - * @timestamp_flags: Timestamp flags; V4L2_BUF_FLAG_TIMESTAMP_* and - * V4L2_BUF_FLAG_TSTAMP_SRC_* + * @timestamp_flags: Timestamp flags; ``V4L2_BUF_FLAG_TIMESTAMP_*`` and + * ``V4L2_BUF_FLAG_TSTAMP_SRC_*`` * @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 + * 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. * @min_buffers_needed: the minimum number of buffers needed before * @start_streaming can be called. Used when a DMA engine @@ -484,20 +487,19 @@ struct vb2_buf_ops { * @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_devs: memory type/allocator-specific per-plane device * @streaming: current streaming state * @start_streaming_called: @start_streaming was called successfully and we * started streaming. * @error: a fatal error occurred on the queue * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for * buffers. Only set for capture queues if qbuf has not yet been - * called since poll() needs to return POLLERR in that situation. + * called since poll() needs to return %POLLERR in that situation. * @is_multiplanar: set if buffer type is multiplanar * @is_output: set if buffer type is output * @copy_timestamp: set if vb2-core should set timestamps * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the * last decoded buffer was already dequeued. Set for capture queues - * when a buffer with the V4L2_BUF_FLAG_LAST is dequeued. + * when a buffer with the %V4L2_BUF_FLAG_LAST is dequeued. * @fileio: file io emulator internal data, used only if emulator is active * @threadio: thread io internal data, used only if thread is active */ @@ -525,6 +527,8 @@ struct vb2_queue { gfp_t gfp_flags; u32 min_buffers_needed; + struct device *alloc_devs[VB2_MAX_PLANES]; + /* private: internal use only */ struct mutex mmap_lock; unsigned int memory; @@ -540,8 +544,6 @@ struct vb2_queue { spinlock_t done_lock; wait_queue_head_t done_wq; - struct device *alloc_devs[VB2_MAX_PLANES]; - unsigned int streaming:1; unsigned int start_streaming_called:1; unsigned int error:1; @@ -568,9 +570,10 @@ struct vb2_queue { }; /** - * 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 + * vb2_plane_vaddr() - Return a kernel virtual address of a given plane. + * @vb: pointer to &struct 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. @@ -578,9 +581,10 @@ struct vb2_queue { 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 + * vb2_plane_cookie() - Return allocator specific cookie for the given plane. + * @vb: pointer to &struct 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 @@ -591,9 +595,11 @@ void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no); 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 + * vb2_buffer_done() - inform videobuf that an operation on a buffer + * is finished. + * @vb: pointer to &struct vb2_buffer to be used. + * @state: state of the buffer, as defined by &enum vb2_buffer_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 @@ -614,8 +620,8 @@ 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); /** - * vb2_discard_done() - discard all buffers marked as DONE - * @q: videobuf2 queue + * vb2_discard_done() - discard all buffers marked as DONE. + * @q: pointer to &struct vb2_queue with 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 @@ -628,74 +634,83 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state); 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 + * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2. + * @q: pointer to &struct vb2_queue with videobuf2 queue. * * This function will wait until all buffers that have been given to the driver * by &vb2_ops->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 &vb2_ops->stop_streaming callback. + * doesn't call &vb2_ops->wait_prepare/&vb2_ops->wait_finish pair. + * It is intended to be called with all locks taken, for example from + * &vb2_ops->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 + * vb2_core_querybuf() - query video buffer information. + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @index: id number of the buffer. + * @pb: buffer struct passed from userspace. + * + * Videobuf2 core helper to implement VIDIOC_QUERYBUF() operation. It is called + * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. * - * 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. + * + * Return: returns zero on success; an error code otherwise. */ 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 + * vb2_core_reqbufs() - Initiate streaming. + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @memory: memory type, as defined by &enum vb2_memory. + * @count: requested buffer count. * - * Should be called from vidioc_reqbufs ioctl handler of a driver. + * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called + * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. * * This function: * - * #) verifies streaming parameters passed from the userspace, - * #) sets up the queue, + * #) verifies streaming parameters passed from the userspace; + * #) sets up the queue; * #) negotiates number of buffers and planes per buffer with the driver - * to be used during streaming, - * #) allocates internal buffer structures (struct vb2_buffer), according to - * the agreed parameters, + * to be used during streaming; + * #) allocates internal buffer structures (&struct vb2_buffer), according to + * the agreed parameters; * #) for MMAP memory type, allocates actual video memory, using the - * memory handling/allocation routines provided during queue initialization + * 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. + * If the queue has been allocated previously by a previous vb2_core_reqbufs() + * call and the queue is not busy, memory will be reallocated. + * + * Return: returns zero on success; an error code otherwise. */ 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 - * @requested_planes: number of planes requested - * @requested_sizes: array with the size of the planes + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @memory: memory type, as defined by &enum vb2_memory. + * @count: requested buffer count. + * @requested_planes: number of planes requested. + * @requested_sizes: array with the size of the planes. + * + * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is + * called internally by VB2 by an API-specific handler, like + * ``videobuf2-v4l2.h``. * - * Should be called from VIDIOC_CREATE_BUFS() ioctl handler of a driver. * This function: * - * #) verifies parameter sanity - * #) calls the .queue_setup() queue operation - * #) performs any necessary memory allocations + * #) verifies parameter sanity; + * #) calls the &vb2_ops->queue_setup queue operation; + * #) performs any necessary memory allocations. * - * Return: the return values from this function are intended to be directly - * returned from VIDIOC_CREATE_BUFS() handler in driver. + * Return: returns zero on success; an error code otherwise. */ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory, unsigned int *count, unsigned int requested_planes, @@ -703,57 +718,61 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory, /** * 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 + * to the kernel. + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @index: id number of the buffer. + * @pb: buffer structure passed from userspace to + * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver. + * + * Videobuf2 core helper to implement VIDIOC_PREPARE_BUF() operation. It is + * called internally by VB2 by an API-specific handler, like + * ``videobuf2-v4l2.h``. * - * 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. + * This function calls vb2_ops->buf_prepare callback in the driver + * (if provided), in which driver-specific buffer initialization can + * be performed. + * + * Return: returns zero on success; an error code otherwise. */ 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 + * @q: pointer to &struct vb2_queue with videobuf2 queue. * @index: id number of the buffer - * @pb: buffer structure passed from userspace to vidioc_qbuf handler - * in driver + * @pb: buffer structure passed from userspace to + * v4l2_ioctl_ops->vidioc_qbuf handler in driver * - * Should be called from vidioc_qbuf ioctl handler of a driver. - * The passed buffer should have been verified. + * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called + * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. * * This function: * - * #) if necessary, calls buf_prepare callback in the driver (if provided), in - * which driver-specific buffer initialization can be performed, + * #) if necessary, calls &vb2_ops->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 * &vb2_ops->buf_queue callback for processing. * - * The return values from this function are intended to be directly returned - * from vidioc_qbuf handler in driver. + * Return: returns zero on success; an error code otherwise. */ 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 + * @q: pointer to &struct vb2_queue with videobuf2 queue * @pindex: pointer to the buffer index. May be NULL - * @pb: buffer structure passed from userspace to vidioc_dqbuf handler - * in driver + * @pb: buffer structure passed from userspace to + * v4l2_ioctl_ops->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 + * 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. + * Videobuf2 core helper to implement VIDIOC_DQBUF() operation. It is called + * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. * * This function: * @@ -763,73 +782,108 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb); * #) 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. + * Return: returns zero on success; an error code otherwise. */ int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb, bool nonblocking); +/** + * vb2_core_streamon() - Implements VB2 stream ON logic + * + * @q: pointer to &struct vb2_queue with videobuf2 queue + * @type: type of the queue to be started. + * For V4L2, this is defined by &enum v4l2_buf_type type. + * + * Videobuf2 core helper to implement VIDIOC_STREAMON() operation. It is called + * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. + * + * Return: returns zero on success; an error code otherwise. + */ int vb2_core_streamon(struct vb2_queue *q, unsigned int type); + +/** + * vb2_core_streamoff() - Implements VB2 stream OFF logic + * + * @q: pointer to &struct vb2_queue with videobuf2 queue + * @type: type of the queue to be started. + * For V4L2, this is defined by &enum v4l2_buf_type type. + * + * Videobuf2 core helper to implement VIDIOC_STREAMOFF() operation. It is + * called internally by VB2 by an API-specific handler, like + * ``videobuf2-v4l2.h``. + * + * Return: returns zero on success; an error code otherwise. + */ 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 + * vb2_core_expbuf() - Export a buffer as a file descriptor. + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @fd: pointer to the 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 + * @flags: file flags for newly created file, as defined at + * include/uapi/asm-generic/fcntl.h. + * Currently, the only used flag is %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. + * + * Videobuf2 core helper to implement VIDIOC_EXPBUF() operation. It is called + * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``. + * + * Return: returns zero on success; an error code otherwise. */ 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 + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * This structure should be allocated in driver * - * The vb2_queue structure should be allocated by the driver. The driver is + * 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. + * + * .. note:: + * + * The following fields at @q should be set before calling this function: + * &vb2_queue->ops, &vb2_queue->mem_ops, &vb2_queue->type. */ int vb2_core_queue_init(struct vb2_queue *q); /** * vb2_core_queue_release() - stop streaming, release the queue and free memory - * @q: videobuf2 queue + * @q: pointer to &struct vb2_queue with 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. + * the &struct vb2_queue itself. */ void vb2_core_queue_release(struct vb2_queue *q); /** * vb2_queue_error() - signal a fatal error on the queue - * @q: videobuf2 queue + * @q: pointer to &struct vb2_queue with 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. + * 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 + * The error flag will be cleared when canceling 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 + * vb2_mmap() - map video buffers into application address space. + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @vma: pointer to &struct vm_area_struct with the 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 @@ -837,8 +891,10 @@ void vb2_queue_error(struct vb2_queue *q); * 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. + * to it earlier by the means of &v4l2_ioctl_ops->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. * @@ -848,6 +904,21 @@ void vb2_queue_error(struct vb2_queue *q); int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma); #ifndef CONFIG_MMU +/** + * vb2_get_unmapped_area - map video buffers into application address space. + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @addr: memory address. + * @len: buffer size. + * @pgoff: page offset. + * @flags: memory flags. + * + * This function is used in noMMU platforms to propose address mapping + * for a given buffer. It's intended to be used as a handler for the + * &file_operations->get_unmapped_area operation. + * + * This is called by the mmap() syscall routines will call this + * to get a proposed address for the mapping, when ``!CONFIG_MMU``. + */ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, unsigned long addr, unsigned long len, @@ -856,10 +927,12 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, #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 + * vb2_core_poll() - implements poll syscall() logic. + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @file: &struct file argument passed to the poll + * file operation handler. + * @wait: &poll_table 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 @@ -874,16 +947,32 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file, poll_table *wait); +/** + * vb2_read() - implements read() syscall logic. + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @data: pointed to target userspace buffer + * @count: number of bytes to read + * @ppos: file handle position tracking pointer + * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking) + */ size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count, loff_t *ppos, int nonblock); +/** + * vb2_read() - implements write() syscall logic. + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @data: pointed to target userspace buffer + * @count: number of bytes to write + * @ppos: file handle position tracking pointer + * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking) + */ size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count, loff_t *ppos, int nonblock); /** - * typedef vb2_thread_fnc - callback function for use with vb2_thread + * typedef vb2_thread_fnc - callback function for use with vb2_thread. * - * @vb: pointer to struct &vb2_buffer - * @priv: pointer to a private pointer + * @vb: pointer to struct &vb2_buffer. + * @priv: pointer to a private data. * * This is called whenever a buffer is dequeued in the thread. */ @@ -891,13 +980,13 @@ typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv); /** * vb2_thread_start() - start a thread for the given queue. - * @q: videobuf queue - * @fnc: callback function - * @priv: priv pointer passed to the callback function + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @fnc: &vb2_thread_fnc callback function. + * @priv: priv pointer passed to the callback function. * @thread_name:the name of the thread. This will be prefixed with "vb2-". * * This starts a thread that will queue and dequeue until an error occurs - * or @vb2_thread_stop is called. + * or vb2_thread_stop() is called. * * .. attention:: * @@ -910,13 +999,13 @@ int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv, /** * vb2_thread_stop() - stop the thread for the given queue. - * @q: videobuf queue + * @q: pointer to &struct vb2_queue with videobuf2 queue. */ int vb2_thread_stop(struct vb2_queue *q); /** - * vb2_is_streaming() - return streaming status of the queue - * @q: videobuf queue + * vb2_is_streaming() - return streaming status of the queue. + * @q: pointer to &struct vb2_queue with videobuf2 queue. */ static inline bool vb2_is_streaming(struct vb2_queue *q) { @@ -925,15 +1014,16 @@ static inline bool vb2_is_streaming(struct vb2_queue *q) /** * vb2_fileio_is_active() - return true if fileio is active. - * @q: videobuf queue + * @q: pointer to &struct vb2_queue with videobuf2 queue. * * This returns true if read() or write() is used to stream the data * as opposed to stream I/O. This is almost never an important distinction, * except in rare cases. One such case is that using read() or write() to - * stream a format using V4L2_FIELD_ALTERNATE is not allowed since there + * stream a format using %V4L2_FIELD_ALTERNATE is not allowed since there * is no way you can pass the field information of each buffer to/from * userspace. A driver that supports this field format should check for - * this in the queue_setup op and reject it if this function returns true. + * this in the &vb2_ops->queue_setup op and reject it if this function returns + * true. */ static inline bool vb2_fileio_is_active(struct vb2_queue *q) { @@ -941,8 +1031,8 @@ static inline bool vb2_fileio_is_active(struct vb2_queue *q) } /** - * vb2_is_busy() - return busy status of the queue - * @q: videobuf queue + * vb2_is_busy() - return busy status of the queue. + * @q: pointer to &struct vb2_queue with videobuf2 queue. * * This function checks if queue has any buffers allocated. */ @@ -952,8 +1042,8 @@ static inline bool vb2_is_busy(struct vb2_queue *q) } /** - * vb2_get_drv_priv() - return driver private data associated with the queue - * @q: videobuf queue + * vb2_get_drv_priv() - return driver private data associated with the queue. + * @q: pointer to &struct vb2_queue with videobuf2 queue. */ static inline void *vb2_get_drv_priv(struct vb2_queue *q) { @@ -961,10 +1051,11 @@ static inline void *vb2_get_drv_priv(struct vb2_queue *q) } /** - * 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 + * vb2_set_plane_payload() - set bytesused for the plane @plane_no. + * @vb: pointer to &struct vb2_buffer to which the plane in + * question belongs to. + * @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) @@ -975,8 +1066,9 @@ static inline void vb2_set_plane_payload(struct vb2_buffer *vb, /** * 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 + * @vb: pointer to &struct vb2_buffer to which the plane in + * question belongs to. + * @plane_no: plane number for which payload should be set. */ static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb, unsigned int plane_no) @@ -987,9 +1079,10 @@ static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb, } /** - * 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 + * vb2_plane_size() - return plane size in bytes. + * @vb: pointer to &struct vb2_buffer to which the plane in + * question belongs to. + * @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) @@ -1000,8 +1093,8 @@ vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no) } /** - * vb2_start_streaming_called() - return streaming status of driver - * @q: videobuf queue + * vb2_start_streaming_called() - return streaming status of driver. + * @q: pointer to &struct vb2_queue with videobuf2 queue. */ static inline bool vb2_start_streaming_called(struct vb2_queue *q) { @@ -1009,8 +1102,8 @@ static inline bool vb2_start_streaming_called(struct vb2_queue *q) } /** - * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue - * @q: videobuf queue + * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue. + * @q: pointer to &struct vb2_queue with videobuf2 queue. */ static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q) { @@ -1024,10 +1117,10 @@ static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q) /** * 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 + * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call. * - * @vb: buffer for which plane size should be returned - * @q: videobuf queue + * @vb: buffer for which plane size should be returned. + * @q: pointer to &struct vb2_queue with videobuf2 queue. */ bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb); @@ -1035,11 +1128,11 @@ 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. * - * @q: videobuf queue + * @q: pointer to &struct vb2_queue with videobuf2 queue. * @memory: memory model, as defined by enum &vb2_memory. * @type: private buffer type whose content is defined by the vb2-core * caller. For example, for V4L2, it should match - * the types defined on enum &v4l2_buf_type + * the types defined on enum &v4l2_buf_type. */ int vb2_verify_memory_type(struct vb2_queue *q, enum vb2_memory memory, unsigned int type); |