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Commit 2b141324 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab
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media: vb2-core: Improve kernel-doc markups 

There are several issues on the current markups:
- lack of cross-references;
- wrong cross-references;
- lack of a period of the end of several phrases;
- Some descriptions can be enhanced.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent 37bc2d87
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Showing with 204 additions and 172 deletions
include/media/videobuf2-core.h
View file @ 2b141324
......@@ -46,7 +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
......@@ -146,27 +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.
* @m: Union with memtype-specific data
* @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)
* 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
* pointing to this plane.
* @m.fd: when memory is %VB2_MEMORY_DMABUF, a userspace file
* descriptor associated with this plane
* 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;
......@@ -184,12 +185,12 @@ 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 = BIT(0),
......@@ -200,19 +201,19 @@ enum vb2_io_modes {
};
/**
* 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
......@@ -356,17 +358,17 @@ struct vb2_buffer {
* 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() with %%VB2_BUF_STATE_QUEUED.
* 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
* 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_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
......@@ -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.
* 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);
......@@ -418,12 +420,13 @@ 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.
......@@ -443,7 +446,7 @@ struct vb2_buf_ops {
* @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
......@@ -454,15 +457,15 @@ 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
* to force the buffer allocation to a specific memory zone.
......@@ -484,7 +487,6 @@ 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.
......@@ -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
......@@ -628,35 +634,40 @@ 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.
*
* Should be called from &v4l2_ioctl_ops->vidioc_querybuf ioctl handler
* in driver.
*
* 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
* 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.
* Should be called from &v4l2_ioctl_ops->vidioc_reqbufs ioctl
* handler of a driver.
*
* This function:
*
......@@ -670,32 +681,35 @@ void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
* 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.
*
* If the queue has been allocated previously by a previous vb2_core_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.
* from &v4l2_ioctl_ops->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
* @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.
*
* Should be called from &v4l2_ioctl_ops->vidioc_create_bufs ioctl handler
* of a driver.
*
* Should be called from VIDIOC_CREATE_BUFS() ioctl handler of a driver.
* This function:
*
* #) verifies parameter sanity
* #) calls the .queue_setup() queue operation
* #) 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.
* returned from &v4l2_ioctl_ops->vidioc_create_bufs handler in driver.
*/
int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
unsigned int *count, unsigned int requested_planes,
......@@ -703,31 +717,34 @@ 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.
*
* Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler
* of a 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.
* from v4l2_ioctl_ops->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
* @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.
* Should be called from v4l2_ioctl_ops->vidioc_qbuf ioctl handler of a driver.
* The passed buffer should have been verified.
*
* This function:
......@@ -738,21 +755,21 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
* &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.
* from v4l2_ioctl_ops->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
* @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.
* Should be called from v4l2_ioctl_ops->vidioc_dqbuf ioctl handler of a driver.
* The passed buffer should have been verified.
*
* This function:
......@@ -764,7 +781,7 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb);
* the userspace.
*
* The return values from this function are intended to be directly returned
* from vidioc_dqbuf handler in driver.
* from v4l2_ioctl_ops->vidioc_dqbuf handler in driver.
*/
int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
bool nonblocking);
......@@ -773,51 +790,57 @@ 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
* 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.
* from v4l2_ioctl_ops->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
* @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
* 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 canceling the queue, either from
* vb2_streamoff() or vb2_queue_release(). Drivers should thus not call this
......@@ -827,9 +850,10 @@ void vb2_core_queue_release(struct vb2_queue *q);
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 +861,10 @@ 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.
*
......@@ -856,10 +882,12 @@ 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 userspace operation.
* @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
......@@ -880,10 +908,10 @@ 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 +919,13 @@ 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 +938,13 @@ 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 +953,16 @@ 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 +970,8 @@ 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 +981,8 @@ 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 +990,11 @@ 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 +1005,9 @@ 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 +1018,10 @@ 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 +1032,8 @@ 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 +1041,8 @@ 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 +1056,10 @@ 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 +1067,11 @@ 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);
......
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