#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)
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
* 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;
};
/**
- * 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;
};
/**
- * 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,
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;
unsigned int type;
unsigned int memory;
unsigned int num_planes;
- struct vb2_plane planes[VB2_MAX_PLANES];
u64 timestamp;
/* private: internal use only
* 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
};
/**
- * 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
* 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
};
/**
- * 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);
};
/**
- * 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
* @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
* 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
* @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
*/
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;
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;
};
/**
- * 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.
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
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
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
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,
/**
* 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:
*
* #) 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
* 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.
*
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,
#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
__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.
*/
/**
* 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::
*
/**
* 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)
{
/**
* 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)
{
}
/**
- * 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.
*/
}
/**
- * 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)
{
}
/**
- * 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)
/**
* 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)
}
/**
- * 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)
}
/**
- * 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)
{
}
/**
- * 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)
{
/**
* 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);
* 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);
git.samba.org / sfrench / cifs-2.6.git / blobdiff