/* * videobuf2-core.h - Video Buffer 2 Core Framework * * Copyright (C) 2010 Samsung Electronics * * Author: Pawel Osciak <[email protected]> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation. */ #ifndef _MEDIA_VIDEOBUF2_CORE_H #define _MEDIA_VIDEOBUF2_CORE_H #include <linux/mm_types.h> #include <linux/mutex.h> #include <linux/poll.h> #include <linux/dma-buf.h> #include <linux/bitops.h> #include <media/media-request.h> #include <media/frame_vector.h> #define VB2_MAX_FRAME … #define VB2_MAX_PLANES … /** * enum vb2_memory - type of memory model used to make the buffers visible * on userspace. * * @VB2_MEMORY_UNKNOWN: Buffer status is unknown or it is not used yet on * userspace. * @VB2_MEMORY_MMAP: The buffers are allocated by the Kernel and it is * memory mapped via mmap() ioctl. This model is * also used when the user is using the buffers via * read() or write() system calls. * @VB2_MEMORY_USERPTR: The buffers was allocated in userspace and it is * memory mapped via mmap() ioctl. * @VB2_MEMORY_DMABUF: The buffers are passed to userspace via DMA buffer. */ enum vb2_memory { … }; struct vb2_fileio_data; struct vb2_threadio_data; struct vb2_buffer; /** * 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 * will then be passed as @buf_priv argument to other ops in this * structure. The size argument to this function shall be * *page aligned*. * @put: inform the allocator that the buffer will no longer be used; * usually will result in the allocator freeing the buffer (if * no other users of this buffer are present); the @buf_priv * argument is the allocator private per-buffer structure * previously returned from the alloc callback. * @get_dmabuf: acquire userspace memory for a hardware operation; used for * DMABUF memory types. * @get_userptr: acquire userspace memory for a hardware operation; used for * USERPTR memory types; vaddr is the address passed to the * videobuf2 layer when queuing a video buffer of USERPTR type; * should return an allocator private per-buffer structure * associated with the buffer on success, ERR_PTR() on failure; * the returned private structure will then be passed as @buf_priv * argument to other ops in this structure. * @put_userptr: inform the allocator that a USERPTR buffer will no longer * be used. * @prepare: called every time the buffer is passed from userspace to the * driver, useful for cache synchronisation, optional. * @finish: called every time the buffer is passed back from the driver * to the userspace, also optional. * @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; * this needs to be used for further accesses to the buffer. * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF * buffer is no longer used; the @buf_priv argument is the * allocator private per-buffer structure previously returned * from the attach_dmabuf callback. * @map_dmabuf: request for access to the dmabuf from allocator; the allocator * of dmabuf is informed that this driver is going to use the * dmabuf. * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified * that this driver is done using the dmabuf for now. * @vaddr: return a kernel virtual address to a given memory buffer * associated with the passed private structure or NULL if no * such mapping exists. * @cookie: return allocator specific cookie for a given memory buffer * associated with the passed private structure or NULL if not * available. * @num_users: return the current number of users of a memory buffer; * return 1 if the videobuf2 layer (or actually the driver using * it) is the only user. * @mmap: setup a userspace mapping for a given memory buffer under * the provided virtual memory region. * * Those operations are used by the videobuf2 core to implement the memory * handling/memory allocators for each type of supported streaming I/O method. * * .. note:: * #) Required ops for USERPTR types: get_userptr, put_userptr. * * #) Required ops for MMAP types: alloc, put, num_users, mmap. * * #) Required ops for read/write access types: alloc, put, num_users, vaddr. * * #) Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, * map_dmabuf, unmap_dmabuf. */ struct vb2_mem_ops { … }; /** * 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. The maximum * valid size is MAX_UINT - PAGE_SIZE. * @min_length: minimum required size of this plane (NOT the payload) in bytes. * @length is always greater or equal to @min_length, and like * @length, it is limited to MAX_UINT - PAGE_SIZE. * @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). * @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. * * Should contain enough information to be able to cover all the fields * of &struct v4l2_plane at videodev2.h. */ 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 { … }; /** * enum vb2_buffer_state - current video buffer state. * @VB2_BUF_STATE_DEQUEUED: buffer under userspace control. * @VB2_BUF_STATE_IN_REQUEST: buffer is queued in media request. * @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf2. * @VB2_BUF_STATE_QUEUED: buffer queued in videobuf2, but not in driver. * @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used * in a hardware operation. * @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf2, but * 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. */ enum vb2_buffer_state { … }; struct vb2_queue; /** * 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. * @timestamp: frame timestamp in ns. * @request: the request this buffer is associated with. * @req_obj: used to bind this buffer to a request. This * request object has a refcount. */ struct vb2_buffer { … }; /** * struct vb2_ops - driver-specific callbacks. * * These operations are not called from interrupt context except where * mentioned specifically. * * @queue_setup: called from VIDIOC_REQBUFS() and VIDIOC_CREATE_BUFS() * handlers before memory allocation. It can be called * twice: if the original number of requested buffers * could not be allocated, then it will be called a * second time with the actually allocated number of * buffers to verify if that is OK. * The driver should return the required number of buffers * in \*num_buffers, the required number of planes per * buffer in \*num_planes, the size of each plane should be * set in the sizes\[\] array and optional per-plane * allocator specific device in the alloc_devs\[\] array. * When called from VIDIOC_REQBUFS(), \*num_planes == 0, * the driver has to use the currently configured format to * determine the plane sizes and \*num_buffers is the total * number of buffers that are being allocated. When called * from VIDIOC_CREATE_BUFS(), \*num_planes != 0 and it * describes the requested number of planes and sizes\[\] * contains the requested plane sizes. In this case * \*num_buffers are being allocated additionally to * the buffers already allocated. If either \*num_planes * or the requested sizes are invalid callback must return %-EINVAL. * @wait_prepare: release any locks taken while calling vb2 functions; * it is called before an ioctl needs to wait for a new * buffer to arrive; required to avoid a deadlock in * blocking access type. * @wait_finish: reacquire all locks released in the previous callback; * required to continue operation after sleeping while * waiting for a new buffer to arrive. * @buf_out_validate: called when the output buffer is prepared or queued * to a request; drivers can use this to validate * userspace-provided information; this is required only * for OUTPUT queues. * @buf_init: called once after allocating a buffer (in MMAP case) * or after acquiring a new USERPTR buffer; drivers may * perform additional buffer-related initialization; * initialization failure (return != 0) will prevent * queue setup from completing successfully; optional. * @buf_prepare: called every time the buffer is queued from userspace * and from the VIDIOC_PREPARE_BUF() ioctl; drivers may * perform any initialization required before each * hardware operation in this callback; drivers can * access/modify the buffer here as it is still synced for * the CPU; drivers that support VIDIOC_CREATE_BUFS() must * also validate the buffer size; if an error is returned, * the buffer will not be queued in driver; optional. * @buf_finish: called before every dequeue of the buffer back to * userspace; the buffer is synced for the CPU, so drivers * can access/modify the buffer contents; drivers may * perform any operations required before userspace * accesses the buffer; optional. The buffer state can be * one of the following: %DONE and %ERROR occur while * streaming is in progress, and the %PREPARED state occurs * when the queue has been canceled and all pending * buffers are being returned to their default %DEQUEUED * state. Typically you only have to do something if the * state is %VB2_BUF_STATE_DONE, since in all other cases * the buffer contents will be ignored anyway. * @buf_cleanup: called once before the buffer is freed; drivers may * perform any additional cleanup; optional. * @prepare_streaming: called once to prepare for 'streaming' state; this is * where validation can be done to verify everything is * okay and streaming resources can be claimed. It is * called when the VIDIOC_STREAMON ioctl is called. The * actual streaming starts when @start_streaming is called. * Optional. * @start_streaming: called once to enter 'streaming' state; the driver may * receive buffers with @buf_queue callback * before @start_streaming is called; the driver gets the * number of already queued buffers in count parameter; * 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. * If you need a minimum number of buffers before you can * start streaming, then set * &vb2_queue->min_queued_buffers. 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_wait_for_all_buffers() function * @unprepare_streaming:called as counterpart to @prepare_streaming; any claimed * streaming resources can be released here. It is * called when the VIDIOC_STREAMOFF ioctls is called or * when the streaming filehandle is closed. Optional. * @buf_queue: passes buffer vb to the driver; driver may start * hardware operation on this buffer; driver should give * the buffer back by calling vb2_buffer_done() function; * it is always called after calling VIDIOC_STREAMON() * ioctl; might be called before @start_streaming callback * if user pre-queued buffers before calling * VIDIOC_STREAMON(). * @buf_request_complete: a buffer that was never queued to the driver but is * associated with a queued request was canceled. * The driver will have to mark associated objects in the * request as completed; required if requests are * supported. */ struct vb2_ops { … }; /** * 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. * @init_buffer: given a &vb2_buffer initialize the extra data after * struct vb2_buffer. * For V4L2 this is a &struct vb2_v4l2_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 &struct vb2_buffer. */ struct vb2_buf_ops { … }; /** * struct vb2_queue - a videobuf2 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 &enum vb2_io_modes). * @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 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 * 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 * the buffer (in the opposite direction) this could lead to an * IOMMU protection faults. * @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 %EPOLLERR at poll when QBUF * has not been called. This is a vb1 idiom that has been adopted * also by vb2. * @supports_requests: this queue supports the Request API. * @requires_requests: this queue requires the Request API. If this is set to 1, * then supports_requests must be set to 1 as well. * @uses_qbuf: qbuf was used directly for this queue. Set to 1 the first * time this is called. Set to 0 when the queue is canceled. * If this is 1, then you cannot queue buffers from a request. * @uses_requests: requests are used for this queue. Set to 1 the first time * a request is queued. Set to 0 when the queue is canceled. * If this is 1, then you cannot queue buffers directly. * @allow_cache_hints: when set user-space can pass cache management hints in * order to skip cache flush/invalidation on ->prepare() or/and * ->finish(). * @non_coherent_mem: when set queue will attempt to allocate buffers using * non-coherent memory. * @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 * by the videobuf2 core API. * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle * that called reqbufs, create_buffers or started fileio. * This field is not used by the videobuf2 core API, but it allows * 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. * @subsystem_flags: Flags specific to the subsystem (V4L2/DVB/etc.). Not used * by the vb2 core. * @buf_struct_size: size of the driver-specific buffer structure; * "0" indicates the driver doesn't want to use a custom buffer * structure type. In that case a subsystem-specific struct * will be used (in the case of V4L2 that is * ``sizeof(struct vb2_v4l2_buffer)``). The first field of the * driver-specific buffer structure must be the subsystem-specific * struct (vb2_v4l2_buffer in the case of V4L2). * @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. * @min_queued_buffers: the minimum number of queued buffers needed before * @start_streaming can be called. Used when a DMA engine * cannot be started unless at least this number of buffers * have been queued into the driver. * VIDIOC_REQBUFS will ensure at least @min_queued_buffers + 1 * buffers will be allocated. Note that VIDIOC_CREATE_BUFS will not * modify the requested buffer count. * @min_reqbufs_allocation: the minimum number of buffers to be allocated when * calling VIDIOC_REQBUFS. Note that VIDIOC_CREATE_BUFS will *not* * modify the requested buffer count and does not use this field. * Drivers can set this if there has to be a certain number of * buffers available for the hardware to work effectively. * This allows calling VIDIOC_REQBUFS with a buffer count of 1 and * it will be automatically adjusted to a workable buffer count. * If set, then @min_reqbufs_allocation must be larger than * @min_queued_buffers + 1. * If this field is > 3, then it is highly recommended that the * driver implements the V4L2_CID_MIN_BUFFERS_FOR_CAPTURE/OUTPUT * control. * @alloc_devs: &struct device memory type/allocator-specific per-plane device */ /* * Private elements (won't appear at the uAPI book): * @mmap_lock: private mutex used when buffers are allocated/freed/mmapped * @memory: current memory type used * @dma_dir: DMA mapping direction. * @bufs: videobuf2 buffer structures. If it is non-NULL then * bufs_bitmap is also non-NULL. * @bufs_bitmap: bitmap tracking whether each bufs[] entry is used * @max_num_buffers: upper limit of number of allocated/used buffers. * If set to 0 v4l2 core will change it VB2_MAX_FRAME * for backward compatibility. * @queued_list: list of buffers currently queued from userspace * @queued_count: number of buffers queued and ready for streaming. * @owned_by_drv_count: number of buffers owned by the driver * @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 * @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 %EPOLLERR in that situation. * @waiting_in_dqbuf: set by the core for the duration of a blocking DQBUF, when * it has to wait for a buffer to become available with vb2_queue->lock * released. Used to prevent destroying the queue by other threads. * @is_multiplanar: set if buffer type is multiplanar * @is_output: set if buffer type is output * @is_busy: set if at least one buffer has been allocated at some time. * @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. * @fileio: file io emulator internal data, used only if emulator is active * @threadio: thread io internal data, used only if thread is active * @name: queue name, used for logging purpose. Initialized automatically * if left empty by drivers. */ struct vb2_queue { … }; /** * vb2_queue_allows_cache_hints() - Return true if the queue allows cache * and memory consistency hints. * * @q: pointer to &struct vb2_queue with videobuf2 queue */ static inline bool vb2_queue_allows_cache_hints(struct vb2_queue *q) { … } /** * 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: 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 * inline function, which would convert this cookie to the allocator specific * type that can be used directly by the driver to access the buffer. This can * be for example physical address, pointer to scatter list or IOMMU mapping. */ void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no); /** * vb2_buffer_done() - inform videobuf2 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. * * This function should be called by the driver after a hardware operation on * a buffer is finished and the buffer may be returned to userspace. The driver * cannot use this buffer anymore until it is queued back to it by videobuf * by the means of &vb2_ops->buf_queue callback. Only buffers previously queued * to the driver by &vb2_ops->buf_queue can be passed to this function. * * While streaming a buffer can only be returned in state DONE or ERROR. * The &vb2_ops->start_streaming op can also return them in case the DMA engine * cannot be started for some reason. In that case the buffers should be * returned with state QUEUED to put them back into the queue. */ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state); /** * 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 * resume. * * Drivers must stop the hardware and synchronize with interrupt handlers and/or * delayed works before calling this function to make sure no buffer will be * touched by the driver and/or hardware. */ void vb2_discard_done(struct vb2_queue *q); /** * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2. * @q: 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 &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: pointer to &struct vb2_queue with videobuf2 queue. * @vb: pointer to struct &vb2_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``. * * 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, struct vb2_buffer *vb, void *pb); /** * vb2_core_reqbufs() - Initiate streaming. * @q: pointer to &struct vb2_queue with videobuf2 queue. * @memory: memory type, as defined by &enum vb2_memory. * @flags: auxiliary queue/buffer management flags. Currently, the only * used flag is %V4L2_MEMORY_FLAG_NON_COHERENT. * @count: requested buffer count. * * 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; * #) 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; * #) for MMAP memory type, allocates actual video memory, using the * memory handling/allocation routines provided during queue initialization. * * If req->count is 0, all the memory will be freed instead. * * If the queue has been allocated previously by a previous vb2_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 flags, unsigned int *count); /** * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs * @q: pointer to &struct vb2_queue with videobuf2 queue. * @memory: memory type, as defined by &enum vb2_memory. * @flags: auxiliary queue/buffer management flags. * @count: requested buffer count. * @requested_planes: number of planes requested. * @requested_sizes: array with the size of the planes. * @first_index: index of the first created buffer, all allocated buffers have * indices in the range [first_index..first_index+count-1] * * Videobuf2 core helper to implement VIDIOC_CREATE_BUFS() operation. It is * called internally by VB2 by an API-specific handler, like * ``videobuf2-v4l2.h``. * * This function: * * #) verifies parameter sanity; * #) calls the &vb2_ops->queue_setup queue operation; * #) performs any necessary memory allocations. * * Return: returns zero on success; an error code otherwise. */ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory, unsigned int flags, unsigned int *count, unsigned int requested_planes, const unsigned int requested_sizes[], unsigned int *first_index); /** * vb2_core_prepare_buf() - Pass ownership of a buffer from userspace * to the kernel. * @q: pointer to &struct vb2_queue with videobuf2 queue. * @vb: pointer to struct &vb2_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``. * * The passed buffer should have been verified. * * 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, struct vb2_buffer *vb, void *pb); /** * vb2_core_remove_bufs() - * @q: pointer to &struct vb2_queue with videobuf2 queue. * @start: first index of the range of buffers to remove. * @count: number of buffers to remove. * * Return: returns zero on success; an error code otherwise. */ int vb2_core_remove_bufs(struct vb2_queue *q, unsigned int start, unsigned int count); /** * vb2_core_qbuf() - Queue a buffer from userspace * * @q: pointer to &struct vb2_queue with videobuf2 queue. * @vb: pointer to struct &vb2_buffer. * @pb: buffer structure passed from userspace to * v4l2_ioctl_ops->vidioc_qbuf handler in driver * @req: pointer to &struct media_request, may be NULL. * * 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 @req is non-NULL, then the buffer will be bound to this * media request and it returns. The buffer will be prepared and * queued to the driver (i.e. the next two steps) when the request * itself is queued. * #) 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. * * Return: returns zero on success; an error code otherwise. */ int vb2_core_qbuf(struct vb2_queue *q, struct vb2_buffer *vb, void *pb, struct media_request *req); /** * vb2_core_dqbuf() - Dequeue a buffer to the userspace * @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 * 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. * * 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: * * #) calls buf_finish callback in the driver (if provided), in which * driver can perform any additional operations that may be required before * returning the buffer to userspace, such as cache sync, * #) the buffer struct members are filled with relevant information for * the userspace. * * 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: pointer to &struct vb2_queue with videobuf2 queue. * @fd: pointer to the file descriptor associated with DMABUF * (set by driver). * @type: buffer type. * @vb: pointer to struct &vb2_buffer. * @plane: index of the plane to be exported, 0 for single plane queues * @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. * * * 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, struct vb2_buffer *vb, unsigned int plane, unsigned int flags); /** * vb2_core_queue_init() - initialize a videobuf2 queue * @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. * * .. 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: 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 &struct vb2_queue itself. */ void vb2_core_queue_release(struct vb2_queue *q); /** * vb2_queue_error() - signal a fatal error on the 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 %EPOLLERR 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 * 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: 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 * userspace. To map whole video memory allocated on reqbufs, this function * has to be called once per each plane per each buffer previously allocated. * * When the userspace application calls mmap, it passes to it an offset returned * to it earlier by the means of &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. * * The return values from this function are intended to be directly returned * from the mmap handler in driver. */ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma); #ifndef CONFIG_MMU /** * 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, unsigned long pgoff, unsigned long flags); #endif /** * 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 * be informed that the file descriptor of a video device is available for * reading. * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor * will be reported as available for writing. * * The return values from this function are intended to be directly returned * from poll handler in driver. */ __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_write() - 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. * * @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_fnc; /** * vb2_thread_start() - start a thread for the given queue. * @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. * * .. attention:: * * This function should not be used for anything else but the videobuf2-dvb * support. If you think you have another good use-case for this, then please * contact the linux-media mailing list first. */ int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv, const char *thread_name); /** * vb2_thread_stop() - stop the thread for the given 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: 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: 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 * 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 &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_get_num_buffers() - get the number of buffer in a queue * @q: pointer to &struct vb2_queue with videobuf2 queue. */ static inline unsigned int vb2_get_num_buffers(struct vb2_queue *q) { … } /** * 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. */ static inline bool vb2_is_busy(struct vb2_queue *q) { … } /** * 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: 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: 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: 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: 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: pointer to &struct vb2_queue with videobuf2 queue. */ static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q) { … } /** * vb2_get_buffer() - get a buffer from a queue * @q: pointer to &struct vb2_queue with videobuf2 queue. * @index: buffer index * * This function obtains a buffer from a queue, by its index. * Keep in mind that there is no refcounting involved in this * operation, so the buffer lifetime should be taken into * consideration. */ static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q, unsigned int index) { … } /* * The following functions are not part of the vb2 core API, but are useful * functions for videobuf2-*. */ /** * vb2_buffer_in_use() - return true if the buffer is in use and * the queue cannot be freed (by the means of VIDIOC_REQBUFS(0)) call. * * @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: 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. */ int vb2_verify_memory_type(struct vb2_queue *q, enum vb2_memory memory, unsigned int type); /** * vb2_request_object_is_buffer() - return true if the object is a buffer * * @obj: the request object. */ bool vb2_request_object_is_buffer(struct media_request_object *obj); /** * vb2_request_buffer_cnt() - return the number of buffers in the request * * @req: the request. */ unsigned int vb2_request_buffer_cnt(struct media_request *req); #endif /* _MEDIA_VIDEOBUF2_CORE_H */
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