/* * videobuf2-v4l2.c - V4L2 driver helper framework * * Copyright (C) 2010 Samsung Electronics * * Author: Pawel Osciak * Marek Szyprowski * * The vb2_thread implementation was based on code from videobuf-dvb.c: * (c) 2004 Gerd Knorr [SUSE Labs] * * 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. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "videobuf2-internal.h" /* Flags that are set by the vb2 core */ #define V4L2_BUFFER_MASK_FLAGS (V4L2_BUF_FLAG_MAPPED | V4L2_BUF_FLAG_QUEUED | \ V4L2_BUF_FLAG_DONE | V4L2_BUF_FLAG_ERROR | \ V4L2_BUF_FLAG_PREPARED | \ V4L2_BUF_FLAG_TIMESTAMP_MASK) /* Output buffer flags that should be passed on to the driver */ #define V4L2_BUFFER_OUT_FLAGS (V4L2_BUF_FLAG_PFRAME | V4L2_BUF_FLAG_BFRAME | \ V4L2_BUF_FLAG_KEYFRAME | V4L2_BUF_FLAG_TIMECODE) /** * __verify_planes_array() - verify that the planes array passed in struct * v4l2_buffer from userspace can be safely used */ static int __verify_planes_array(struct vb2_buffer *vb, const struct v4l2_buffer *b) { if (!V4L2_TYPE_IS_MULTIPLANAR(b->type)) return 0; /* Is memory for copying plane information present? */ if (NULL == b->m.planes) { dprintk(1, "multi-planar buffer passed but " "planes array not provided\n"); return -EINVAL; } if (b->length < vb->num_planes || b->length > VB2_MAX_PLANES) { dprintk(1, "incorrect planes array length, " "expected %d, got %d\n", vb->num_planes, b->length); return -EINVAL; } return 0; } static int __verify_planes_array_core(struct vb2_buffer *vb, const void *pb) { return __verify_planes_array(vb, pb); } /** * __verify_length() - Verify that the bytesused value for each plane fits in * the plane length and that the data offset doesn't exceed the bytesused value. */ static int __verify_length(struct vb2_buffer *vb, const struct v4l2_buffer *b) { unsigned int length; unsigned int bytesused; unsigned int plane; if (!V4L2_TYPE_IS_OUTPUT(b->type)) return 0; if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) { for (plane = 0; plane < vb->num_planes; ++plane) { length = (b->memory == VB2_MEMORY_USERPTR) ? b->m.planes[plane].length : vb->planes[plane].length; bytesused = b->m.planes[plane].bytesused ? b->m.planes[plane].bytesused : length; if (b->m.planes[plane].bytesused > length) return -EINVAL; } } else { length = (b->memory == VB2_MEMORY_USERPTR) ? b->length : vb->planes[0].length; if (b->bytesused > length) return -EINVAL; } return 0; } static int __set_timestamp(struct vb2_buffer *vb, const void *pb) { const struct v4l2_buffer *b = pb; struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); struct vb2_queue *q = vb->vb2_queue; if (q->is_output) { /* * For output buffers copy the timestamp if needed, * and the timecode field and flag if needed. */ if ((q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) == V4L2_BUF_FLAG_TIMESTAMP_COPY) vbuf->timestamp = b->timestamp; vbuf->flags |= b->flags & V4L2_BUF_FLAG_TIMECODE; if (b->flags & V4L2_BUF_FLAG_TIMECODE) vbuf->timecode = b->timecode; } return 0; }; static void vb2_warn_zero_bytesused(struct vb2_buffer *vb) { static bool check_once; if (check_once) return; check_once = true; WARN_ON(1); pr_warn("use of bytesused == 0 is deprecated and will be removed in the future,\n"); if (vb->vb2_queue->allow_zero_bytesused) pr_warn("use VIDIOC_DECODER_CMD(V4L2_DEC_CMD_STOP) instead.\n"); else pr_warn("use the actual size instead.\n"); } static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b, const char *opname) { if (b->type != q->type) { dprintk(1, "%s: invalid buffer type\n", opname); return -EINVAL; } if (b->index >= q->num_buffers) { dprintk(1, "%s: buffer index out of range\n", opname); return -EINVAL; } if (q->bufs[b->index] == NULL) { /* Should never happen */ dprintk(1, "%s: buffer is NULL\n", opname); return -EINVAL; } if (b->memory != q->memory) { dprintk(1, "%s: invalid memory type\n", opname); return -EINVAL; } return __verify_planes_array(q->bufs[b->index], b); } /** * __fill_v4l2_buffer() - fill in a struct v4l2_buffer with information to be * returned to userspace */ static int __fill_v4l2_buffer(struct vb2_buffer *vb, void *pb) { struct v4l2_buffer *b = pb; struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); struct vb2_queue *q = vb->vb2_queue; unsigned int plane; /* Copy back data such as timestamp, flags, etc. */ b->index = vb->index; b->type = vb->type; b->memory = vb->memory; b->bytesused = 0; b->flags = vbuf->flags; b->field = vbuf->field; b->timestamp = vbuf->timestamp; b->timecode = vbuf->timecode; b->sequence = vbuf->sequence; b->reserved2 = 0; b->reserved = 0; if (q->is_multiplanar) { /* * Fill in plane-related data if userspace provided an array * for it. The caller has already verified memory and size. */ b->length = vb->num_planes; for (plane = 0; plane < vb->num_planes; ++plane) { struct v4l2_plane *pdst = &b->m.planes[plane]; struct vb2_plane *psrc = &vb->planes[plane]; pdst->bytesused = psrc->bytesused; pdst->length = psrc->length; if (q->memory == VB2_MEMORY_MMAP) pdst->m.mem_offset = psrc->m.offset; else if (q->memory == VB2_MEMORY_USERPTR) pdst->m.userptr = psrc->m.userptr; else if (q->memory == VB2_MEMORY_DMABUF) pdst->m.fd = psrc->m.fd; pdst->data_offset = psrc->data_offset; memset(pdst->reserved, 0, sizeof(pdst->reserved)); } } else { /* * We use length and offset in v4l2_planes array even for * single-planar buffers, but userspace does not. */ b->length = vb->planes[0].length; b->bytesused = vb->planes[0].bytesused; if (q->memory == VB2_MEMORY_MMAP) b->m.offset = vb->planes[0].m.offset; else if (q->memory == VB2_MEMORY_USERPTR) b->m.userptr = vb->planes[0].m.userptr; else if (q->memory == VB2_MEMORY_DMABUF) b->m.fd = vb->planes[0].m.fd; } /* * Clear any buffer state related flags. */ b->flags &= ~V4L2_BUFFER_MASK_FLAGS; b->flags |= q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK; if ((q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) != V4L2_BUF_FLAG_TIMESTAMP_COPY) { /* * For non-COPY timestamps, drop timestamp source bits * and obtain the timestamp source from the queue. */ b->flags &= ~V4L2_BUF_FLAG_TSTAMP_SRC_MASK; b->flags |= q->timestamp_flags & V4L2_BUF_FLAG_TSTAMP_SRC_MASK; } switch (vb->state) { case VB2_BUF_STATE_QUEUED: case VB2_BUF_STATE_ACTIVE: b->flags |= V4L2_BUF_FLAG_QUEUED; break; case VB2_BUF_STATE_ERROR: b->flags |= V4L2_BUF_FLAG_ERROR; /* fall through */ case VB2_BUF_STATE_DONE: b->flags |= V4L2_BUF_FLAG_DONE; break; case VB2_BUF_STATE_PREPARED: b->flags |= V4L2_BUF_FLAG_PREPARED; break; case VB2_BUF_STATE_PREPARING: case VB2_BUF_STATE_DEQUEUED: case VB2_BUF_STATE_REQUEUEING: /* nothing */ break; } if (vb2_buffer_in_use(q, vb)) b->flags |= V4L2_BUF_FLAG_MAPPED; return 0; } /** * __fill_vb2_buffer() - fill a vb2_buffer with information provided in a * v4l2_buffer by the userspace. It also verifies that struct * v4l2_buffer has a valid number of planes. */ static int __fill_vb2_buffer(struct vb2_buffer *vb, const void *pb, struct vb2_plane *planes) { struct vb2_queue *q = vb->vb2_queue; const struct v4l2_buffer *b = pb; struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); unsigned int plane; int ret; ret = __verify_length(vb, b); if (ret < 0) { dprintk(1, "plane parameters verification failed: %d\n", ret); return ret; } if (b->field == V4L2_FIELD_ALTERNATE && q->is_output) { /* * If the format's field is ALTERNATE, then the buffer's field * should be either TOP or BOTTOM, not ALTERNATE since that * makes no sense. The driver has to know whether the * buffer represents a top or a bottom field in order to * program any DMA correctly. Using ALTERNATE is wrong, since * that just says that it is either a top or a bottom field, * but not which of the two it is. */ dprintk(1, "the field is incorrectly set to ALTERNATE " "for an output buffer\n"); return -EINVAL; } vbuf->timestamp.tv_sec = 0; vbuf->timestamp.tv_usec = 0; vbuf->sequence = 0; if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) { if (b->memory == VB2_MEMORY_USERPTR) { for (plane = 0; plane < vb->num_planes; ++plane) { planes[plane].m.userptr = b->m.planes[plane].m.userptr; planes[plane].length = b->m.planes[plane].length; } } if (b->memory == VB2_MEMORY_DMABUF) { for (plane = 0; plane < vb->num_planes; ++plane) { planes[plane].m.fd = b->m.planes[plane].m.fd; planes[plane].length = b->m.planes[plane].length; } } /* Fill in driver-provided information for OUTPUT types */ if (V4L2_TYPE_IS_OUTPUT(b->type)) { /* * Will have to go up to b->length when API starts * accepting variable number of planes. * * If bytesused == 0 for the output buffer, then fall * back to the full buffer size. In that case * userspace clearly never bothered to set it and * it's a safe assumption that they really meant to * use the full plane sizes. * * Some drivers, e.g. old codec drivers, use bytesused == 0 * as a way to indicate that streaming is finished. * In that case, the driver should use the * allow_zero_bytesused flag to keep old userspace * applications working. */ for (plane = 0; plane < vb->num_planes; ++plane) { struct vb2_plane *pdst = &planes[plane]; struct v4l2_plane *psrc = &b->m.planes[plane]; /* * Suppress the warning for zero bytesused. * The warning will go away after proper * fix is done for "HACK: vb2: Remove the V4L2 * check for DMABUF" */ /*if (psrc->bytesused == 0) vb2_warn_zero_bytesused(vb);*/ if (vb->vb2_queue->allow_zero_bytesused) pdst->bytesused = psrc->bytesused; else pdst->bytesused = psrc->bytesused ? psrc->bytesused : pdst->length; pdst->data_offset = psrc->data_offset; } } } else { /* * Single-planar buffers do not use planes array, * so fill in relevant v4l2_buffer struct fields instead. * In videobuf we use our internal V4l2_planes struct for * single-planar buffers as well, for simplicity. * * If bytesused == 0 for the output buffer, then fall back * to the full buffer size as that's a sensible default. * * Some drivers, e.g. old codec drivers, use bytesused == 0 as * a way to indicate that streaming is finished. In that case, * the driver should use the allow_zero_bytesused flag to keep * old userspace applications working. */ if (b->memory == VB2_MEMORY_USERPTR) { planes[0].m.userptr = b->m.userptr; planes[0].length = b->length; } if (b->memory == VB2_MEMORY_DMABUF) { planes[0].m.fd = b->m.fd; planes[0].length = b->length; } if (V4L2_TYPE_IS_OUTPUT(b->type)) { if (b->bytesused == 0) vb2_warn_zero_bytesused(vb); if (vb->vb2_queue->allow_zero_bytesused) planes[0].bytesused = b->bytesused; else planes[0].bytesused = b->bytesused ? b->bytesused : planes[0].length; } else planes[0].bytesused = 0; } /* Zero flags that the vb2 core handles */ vbuf->flags = b->flags & ~V4L2_BUFFER_MASK_FLAGS; if ((vb->vb2_queue->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) != V4L2_BUF_FLAG_TIMESTAMP_COPY || !V4L2_TYPE_IS_OUTPUT(b->type)) { /* * Non-COPY timestamps and non-OUTPUT queues will get * their timestamp and timestamp source flags from the * queue. */ vbuf->flags &= ~V4L2_BUF_FLAG_TSTAMP_SRC_MASK; } if (V4L2_TYPE_IS_OUTPUT(b->type)) { /* * For output buffers mask out the timecode flag: * this will be handled later in vb2_internal_qbuf(). * The 'field' is valid metadata for this output buffer * and so that needs to be copied here. */ vbuf->flags &= ~V4L2_BUF_FLAG_TIMECODE; vbuf->field = b->field; } else { /* Zero any output buffer flags as this is a capture buffer */ vbuf->flags &= ~V4L2_BUFFER_OUT_FLAGS; } return 0; } static const struct vb2_buf_ops v4l2_buf_ops = { .verify_planes_array = __verify_planes_array_core, .fill_user_buffer = __fill_v4l2_buffer, .fill_vb2_buffer = __fill_vb2_buffer, .set_timestamp = __set_timestamp, }; /** * vb2_querybuf() - query video buffer information * @q: videobuf queue * @b: buffer struct passed from userspace to vidioc_querybuf handler * in driver * * Should be called from vidioc_querybuf ioctl handler in driver. * This function will verify the passed v4l2_buffer structure and fill the * relevant information for the userspace. * * The return values from this function are intended to be directly returned * from vidioc_querybuf handler in driver. */ int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b) { struct vb2_buffer *vb; int ret; if (b->type != q->type) { dprintk(1, "wrong buffer type\n"); return -EINVAL; } if (b->index >= q->num_buffers) { dprintk(1, "buffer index out of range\n"); return -EINVAL; } vb = q->bufs[b->index]; ret = __verify_planes_array(vb, b); return ret ? ret : vb2_core_querybuf(q, b->index, b); } EXPORT_SYMBOL(vb2_querybuf); /** * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies * the memory and type values. * @q: videobuf2 queue * @req: struct passed from userspace to vidioc_reqbufs handler * in driver */ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req) { int ret = vb2_verify_memory_type(q, req->memory, req->type); return ret ? ret : vb2_core_reqbufs(q, req->memory, &req->count); } EXPORT_SYMBOL_GPL(vb2_reqbufs); /** * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel * @q: videobuf2 queue * @b: buffer structure passed from userspace to vidioc_prepare_buf * handler in driver * * Should be called from vidioc_prepare_buf ioctl handler of a driver. * This function: * 1) verifies the passed buffer, * 2) calls buf_prepare callback in the driver (if provided), in which * driver-specific buffer initialization can be performed, * * The return values from this function are intended to be directly returned * from vidioc_prepare_buf handler in driver. */ int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b) { int ret; if (vb2_fileio_is_active(q)) { dprintk(1, "file io in progress\n"); return -EBUSY; } ret = vb2_queue_or_prepare_buf(q, b, "prepare_buf"); return ret ? ret : vb2_core_prepare_buf(q, b->index, b); } EXPORT_SYMBOL_GPL(vb2_prepare_buf); /** * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies * the memory and type values. * @q: videobuf2 queue * @create: creation parameters, passed from userspace to vidioc_create_bufs * handler in driver */ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create) { int ret = vb2_verify_memory_type(q, create->memory, create->format.type); create->index = q->num_buffers; if (create->count == 0) return ret != -EBUSY ? ret : 0; return ret ? ret : vb2_core_create_bufs(q, create->memory, &create->count, &create->format); } EXPORT_SYMBOL_GPL(vb2_create_bufs); static int vb2_internal_qbuf(struct vb2_queue *q, struct v4l2_buffer *b) { int ret = vb2_queue_or_prepare_buf(q, b, "qbuf"); return ret ? ret : vb2_core_qbuf(q, b->index, b); } /** * vb2_qbuf() - Queue a buffer from userspace * @q: videobuf2 queue * @b: buffer structure passed from userspace to vidioc_qbuf handler * in driver * * Should be called from vidioc_qbuf ioctl handler of a driver. * This function: * 1) verifies the passed buffer, * 2) if necessary, calls buf_prepare callback in the driver (if provided), in * which driver-specific buffer initialization can be performed, * 3) if streaming is on, queues the buffer in driver by the means of buf_queue * callback for processing. * * The return values from this function are intended to be directly returned * from vidioc_qbuf handler in driver. */ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b) { if (vb2_fileio_is_active(q)) { dprintk(1, "file io in progress\n"); return -EBUSY; } return vb2_internal_qbuf(q, b); } EXPORT_SYMBOL_GPL(vb2_qbuf); static int vb2_internal_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking) { int ret; if (b->type != q->type) { dprintk(1, "invalid buffer type\n"); return -EINVAL; } ret = vb2_core_dqbuf(q, b, nonblocking); if (!ret && !q->is_output && b->flags & V4L2_BUF_FLAG_LAST) q->last_buffer_dequeued = true; return ret; } /** * vb2_dqbuf() - Dequeue a buffer to the userspace * @q: videobuf2 queue * @b: buffer structure passed from userspace to vidioc_dqbuf handler * in driver * @nonblocking: if true, this call will not sleep waiting for a buffer if no * buffers ready for dequeuing are present. Normally the driver * would be passing (file->f_flags & O_NONBLOCK) here * * Should be called from vidioc_dqbuf ioctl handler of a driver. * This function: * 1) verifies the passed buffer, * 2) 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, * 3) the buffer struct members are filled with relevant information for * the userspace. * * The return values from this function are intended to be directly returned * from vidioc_dqbuf handler in driver. */ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking) { if (vb2_fileio_is_active(q)) { dprintk(1, "file io in progress\n"); return -EBUSY; } return vb2_internal_dqbuf(q, b, nonblocking); } EXPORT_SYMBOL_GPL(vb2_dqbuf); /** * vb2_streamon - start streaming * @q: videobuf2 queue * @type: type argument passed from userspace to vidioc_streamon handler * * Should be called from vidioc_streamon handler of a driver. * This function: * 1) verifies current state * 2) passes any previously queued buffers to the driver and starts streaming * * The return values from this function are intended to be directly returned * from vidioc_streamon handler in the driver. */ int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type) { if (vb2_fileio_is_active(q)) { dprintk(1, "file io in progress\n"); return -EBUSY; } return vb2_core_streamon(q, type); } EXPORT_SYMBOL_GPL(vb2_streamon); /** * vb2_streamoff - stop streaming * @q: videobuf2 queue * @type: type argument passed from userspace to vidioc_streamoff handler * * Should be called from vidioc_streamoff handler of a driver. * This function: * 1) verifies current state, * 2) stop streaming and dequeues any queued buffers, including those previously * passed to the driver (after waiting for the driver to finish). * * This call can be used for pausing playback. * The return values from this function are intended to be directly returned * from vidioc_streamoff handler in the driver */ int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type) { if (vb2_fileio_is_active(q)) { dprintk(1, "file io in progress\n"); return -EBUSY; } return vb2_core_streamoff(q, type); } EXPORT_SYMBOL_GPL(vb2_streamoff); /** * vb2_expbuf() - Export a buffer as a file descriptor * @q: videobuf2 queue * @eb: export buffer structure passed from userspace to vidioc_expbuf * handler in driver * * The return values from this function are intended to be directly returned * from vidioc_expbuf handler in driver. */ int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb) { return vb2_core_expbuf(q, &eb->fd, eb->type, eb->index, eb->plane, eb->flags); } EXPORT_SYMBOL_GPL(vb2_expbuf); /** * vb2_queue_init() - initialize a videobuf2 queue * @q: videobuf2 queue; this structure should be allocated in driver * * The vb2_queue structure should be allocated by the driver. The driver is * responsible of clearing it's content and setting initial values for some * required entries before calling this function. * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer * to the struct vb2_queue description in include/media/videobuf2-core.h * for more information. */ int vb2_queue_init(struct vb2_queue *q) { /* * Sanity check */ if (WARN_ON(!q) || WARN_ON(q->timestamp_flags & ~(V4L2_BUF_FLAG_TIMESTAMP_MASK | V4L2_BUF_FLAG_TSTAMP_SRC_MASK))) return -EINVAL; /* Warn that the driver should choose an appropriate timestamp type */ WARN_ON((q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) == V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN); /* Warn that vb2_memory should match with v4l2_memory */ if (WARN_ON(VB2_MEMORY_MMAP != (int)V4L2_MEMORY_MMAP) || WARN_ON(VB2_MEMORY_USERPTR != (int)V4L2_MEMORY_USERPTR) || WARN_ON(VB2_MEMORY_DMABUF != (int)V4L2_MEMORY_DMABUF)) return -EINVAL; if (q->buf_struct_size == 0) q->buf_struct_size = sizeof(struct vb2_v4l2_buffer); q->buf_ops = &v4l2_buf_ops; q->is_multiplanar = V4L2_TYPE_IS_MULTIPLANAR(q->type); q->is_output = V4L2_TYPE_IS_OUTPUT(q->type); return vb2_core_queue_init(q); } EXPORT_SYMBOL_GPL(vb2_queue_init); static int __vb2_init_fileio(struct vb2_queue *q, int read); static int __vb2_cleanup_fileio(struct vb2_queue *q); /** * vb2_queue_release() - stop streaming, release the queue and free memory * @q: videobuf2 queue * * This function stops streaming and performs necessary clean ups, including * freeing video buffer memory. The driver is responsible for freeing * the vb2_queue structure itself. */ void vb2_queue_release(struct vb2_queue *q) { __vb2_cleanup_fileio(q); vb2_core_queue_release(q); } EXPORT_SYMBOL_GPL(vb2_queue_release); /** * vb2_poll() - implements poll userspace operation * @q: videobuf2 queue * @file: file argument passed to the poll file operation handler * @wait: wait argument passed to the poll file operation handler * * This function implements poll file operation handler for a driver. * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will * be informed that the file descriptor of a video device is available for * reading. * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor * will be reported as available for writing. * * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any * pending events. * * The return values from this function are intended to be directly returned * from poll handler in driver. */ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait) { struct video_device *vfd = video_devdata(file); unsigned long req_events = poll_requested_events(wait); struct vb2_buffer *vb = NULL; unsigned int res = 0; unsigned long flags; if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) { struct v4l2_fh *fh = file->private_data; if (v4l2_event_pending(fh)) res = POLLPRI; else if (req_events & POLLPRI) poll_wait(file, &fh->wait, wait); } if (!q->is_output && !(req_events & (POLLIN | POLLRDNORM))) return res; if (q->is_output && !(req_events & (POLLOUT | POLLWRNORM))) return res; /* * Start file I/O emulator only if streaming API has not been used yet. */ if (q->num_buffers == 0 && !vb2_fileio_is_active(q)) { if (!q->is_output && (q->io_modes & VB2_READ) && (req_events & (POLLIN | POLLRDNORM))) { if (__vb2_init_fileio(q, 1)) return res | POLLERR; } if (q->is_output && (q->io_modes & VB2_WRITE) && (req_events & (POLLOUT | POLLWRNORM))) { if (__vb2_init_fileio(q, 0)) return res | POLLERR; /* * Write to OUTPUT queue can be done immediately. */ return res | POLLOUT | POLLWRNORM; } } /* * There is nothing to wait for if the queue isn't streaming, or if the * error flag is set. */ if (!vb2_is_streaming(q) || q->error) return res | POLLERR; /* * For compatibility with vb1: if QBUF hasn't been called yet, then * return POLLERR as well. This only affects capture queues, output * queues will always initialize waiting_for_buffers to false. */ if (q->waiting_for_buffers) return res | POLLERR; /* * For output streams you can call write() as long as there are fewer * buffers queued than there are buffers available. */ if (q->is_output && q->fileio && q->queued_count < q->num_buffers) return res | POLLOUT | POLLWRNORM; if (list_empty(&q->done_list)) { /* * If the last buffer was dequeued from a capture queue, * return immediately. DQBUF will return -EPIPE. */ if (q->last_buffer_dequeued) return res | POLLIN | POLLRDNORM; poll_wait(file, &q->done_wq, wait); } /* * Take first buffer available for dequeuing. */ spin_lock_irqsave(&q->done_lock, flags); if (!list_empty(&q->done_list)) vb = list_first_entry(&q->done_list, struct vb2_buffer, done_entry); spin_unlock_irqrestore(&q->done_lock, flags); if (vb && (vb->state == VB2_BUF_STATE_DONE || vb->state == VB2_BUF_STATE_ERROR)) { return (q->is_output) ? res | POLLOUT | POLLWRNORM : res | POLLIN | POLLRDNORM; } return res; } EXPORT_SYMBOL_GPL(vb2_poll); /** * struct vb2_fileio_buf - buffer context used by file io emulator * * vb2 provides a compatibility layer and emulator of file io (read and * write) calls on top of streaming API. This structure is used for * tracking context related to the buffers. */ struct vb2_fileio_buf { void *vaddr; unsigned int size; unsigned int pos; unsigned int queued:1; }; /** * struct vb2_fileio_data - queue context used by file io emulator * * @cur_index: the index of the buffer currently being read from or * written to. If equal to q->num_buffers then a new buffer * must be dequeued. * @initial_index: in the read() case all buffers are queued up immediately * in __vb2_init_fileio() and __vb2_perform_fileio() just cycles * buffers. However, in the write() case no buffers are initially * queued, instead whenever a buffer is full it is queued up by * __vb2_perform_fileio(). Only once all available buffers have * been queued up will __vb2_perform_fileio() start to dequeue * buffers. This means that initially __vb2_perform_fileio() * needs to know what buffer index to use when it is queuing up * the buffers for the first time. That initial index is stored * in this field. Once it is equal to q->num_buffers all * available buffers have been queued and __vb2_perform_fileio() * should start the normal dequeue/queue cycle. * * vb2 provides a compatibility layer and emulator of file io (read and * write) calls on top of streaming API. For proper operation it required * this structure to save the driver state between each call of the read * or write function. */ struct vb2_fileio_data { struct v4l2_requestbuffers req; struct v4l2_plane p; struct v4l2_buffer b; struct vb2_fileio_buf bufs[VB2_MAX_FRAME]; unsigned int cur_index; unsigned int initial_index; unsigned int q_count; unsigned int dq_count; unsigned read_once:1; unsigned write_immediately:1; }; /** * __vb2_init_fileio() - initialize file io emulator * @q: videobuf2 queue * @read: mode selector (1 means read, 0 means write) */ static int __vb2_init_fileio(struct vb2_queue *q, int read) { struct vb2_fileio_data *fileio; int i, ret; unsigned int count = 0; /* * Sanity check */ if (WARN_ON((read && !(q->io_modes & VB2_READ)) || (!read && !(q->io_modes & VB2_WRITE)))) return -EINVAL; /* * Check if device supports mapping buffers to kernel virtual space. */ if (!q->mem_ops->vaddr) return -EBUSY; /* * Check if streaming api has not been already activated. */ if (q->streaming || q->num_buffers > 0) return -EBUSY; /* * Start with count 1, driver can increase it in queue_setup() */ count = 1; dprintk(3, "setting up file io: mode %s, count %d, read_once %d, write_immediately %d\n", (read) ? "read" : "write", count, q->fileio_read_once, q->fileio_write_immediately); fileio = kzalloc(sizeof(struct vb2_fileio_data), GFP_KERNEL); if (fileio == NULL) return -ENOMEM; fileio->read_once = q->fileio_read_once; fileio->write_immediately = q->fileio_write_immediately; /* * Request buffers and use MMAP type to force driver * to allocate buffers by itself. */ fileio->req.count = count; fileio->req.memory = VB2_MEMORY_MMAP; fileio->req.type = q->type; q->fileio = fileio; ret = vb2_core_reqbufs(q, fileio->req.memory, &fileio->req.count); if (ret) goto err_kfree; /* * Check if plane_count is correct * (multiplane buffers are not supported). */ if (q->bufs[0]->num_planes != 1) { ret = -EBUSY; goto err_reqbufs; } /* * Get kernel address of each buffer. */ for (i = 0; i < q->num_buffers; i++) { fileio->bufs[i].vaddr = vb2_plane_vaddr(q->bufs[i], 0); if (fileio->bufs[i].vaddr == NULL) { ret = -EINVAL; goto err_reqbufs; } fileio->bufs[i].size = vb2_plane_size(q->bufs[i], 0); } /* * Read mode requires pre queuing of all buffers. */ if (read) { bool is_multiplanar = q->is_multiplanar; /* * Queue all buffers. */ for (i = 0; i < q->num_buffers; i++) { struct v4l2_buffer *b = &fileio->b; memset(b, 0, sizeof(*b)); b->type = q->type; if (is_multiplanar) { memset(&fileio->p, 0, sizeof(fileio->p)); b->m.planes = &fileio->p; b->length = 1; } b->memory = q->memory; b->index = i; ret = vb2_internal_qbuf(q, b); if (ret) goto err_reqbufs; fileio->bufs[i].queued = 1; } /* * All buffers have been queued, so mark that by setting * initial_index to q->num_buffers */ fileio->initial_index = q->num_buffers; fileio->cur_index = q->num_buffers; } /* * Start streaming. */ ret = vb2_core_streamon(q, q->type); if (ret) goto err_reqbufs; return ret; err_reqbufs: fileio->req.count = 0; vb2_core_reqbufs(q, fileio->req.memory, &fileio->req.count); err_kfree: q->fileio = NULL; kfree(fileio); return ret; } /** * __vb2_cleanup_fileio() - free resourced used by file io emulator * @q: videobuf2 queue */ static int __vb2_cleanup_fileio(struct vb2_queue *q) { struct vb2_fileio_data *fileio = q->fileio; if (fileio) { vb2_core_streamoff(q, q->type); q->fileio = NULL; fileio->req.count = 0; vb2_reqbufs(q, &fileio->req); kfree(fileio); dprintk(3, "file io emulator closed\n"); } return 0; } /** * __vb2_perform_fileio() - perform a single file io (read or write) operation * @q: videobuf2 queue * @data: pointed to target userspace buffer * @count: number of bytes to read or write * @ppos: file handle position tracking pointer * @nonblock: mode selector (1 means blocking calls, 0 means nonblocking) * @read: access mode selector (1 means read, 0 means write) */ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_t count, loff_t *ppos, int nonblock, int read) { struct vb2_fileio_data *fileio; struct vb2_fileio_buf *buf; bool is_multiplanar = q->is_multiplanar; /* * When using write() to write data to an output video node the vb2 core * should set timestamps if V4L2_BUF_FLAG_TIMESTAMP_COPY is set. Nobody * else is able to provide this information with the write() operation. */ bool set_timestamp = !read && (q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) == V4L2_BUF_FLAG_TIMESTAMP_COPY; int ret, index; dprintk(3, "mode %s, offset %ld, count %zd, %sblocking\n", read ? "read" : "write", (long)*ppos, count, nonblock ? "non" : ""); if (!data) return -EINVAL; /* * Initialize emulator on first call. */ if (!vb2_fileio_is_active(q)) { ret = __vb2_init_fileio(q, read); dprintk(3, "vb2_init_fileio result: %d\n", ret); if (ret) return ret; } fileio = q->fileio; /* * Check if we need to dequeue the buffer. */ index = fileio->cur_index; if (index >= q->num_buffers) { /* * Call vb2_dqbuf to get buffer back. */ memset(&fileio->b, 0, sizeof(fileio->b)); fileio->b.type = q->type; fileio->b.memory = q->memory; if (is_multiplanar) { memset(&fileio->p, 0, sizeof(fileio->p)); fileio->b.m.planes = &fileio->p; fileio->b.length = 1; } ret = vb2_internal_dqbuf(q, &fileio->b, nonblock); dprintk(5, "vb2_dqbuf result: %d\n", ret); if (ret) return ret; fileio->dq_count += 1; fileio->cur_index = index = fileio->b.index; buf = &fileio->bufs[index]; /* * Get number of bytes filled by the driver */ buf->pos = 0; buf->queued = 0; buf->size = read ? vb2_get_plane_payload(q->bufs[index], 0) : vb2_plane_size(q->bufs[index], 0); /* Compensate for data_offset on read in the multiplanar case. */ if (is_multiplanar && read && fileio->b.m.planes[0].data_offset < buf->size) { buf->pos = fileio->b.m.planes[0].data_offset; buf->size -= buf->pos; } } else { buf = &fileio->bufs[index]; } /* * Limit count on last few bytes of the buffer. */ if (buf->pos + count > buf->size) { count = buf->size - buf->pos; dprintk(5, "reducing read count: %zd\n", count); } /* * Transfer data to userspace. */ dprintk(3, "copying %zd bytes - buffer %d, offset %u\n", count, index, buf->pos); if (read) ret = copy_to_user(data, buf->vaddr + buf->pos, count); else ret = copy_from_user(buf->vaddr + buf->pos, data, count); if (ret) { dprintk(3, "error copying data\n"); return -EFAULT; } /* * Update counters. */ buf->pos += count; *ppos += count; /* * Queue next buffer if required. */ if (buf->pos == buf->size || (!read && fileio->write_immediately)) { /* * Check if this is the last buffer to read. */ if (read && fileio->read_once && fileio->dq_count == 1) { dprintk(3, "read limit reached\n"); return __vb2_cleanup_fileio(q); } /* * Call vb2_qbuf and give buffer to the driver. */ memset(&fileio->b, 0, sizeof(fileio->b)); fileio->b.type = q->type; fileio->b.memory = q->memory; fileio->b.index = index; fileio->b.bytesused = buf->pos; if (is_multiplanar) { memset(&fileio->p, 0, sizeof(fileio->p)); fileio->p.bytesused = buf->pos; fileio->b.m.planes = &fileio->p; fileio->b.length = 1; } if (set_timestamp) v4l2_get_timestamp(&fileio->b.timestamp); ret = vb2_internal_qbuf(q, &fileio->b); dprintk(5, "vb2_dbuf result: %d\n", ret); if (ret) return ret; /* * Buffer has been queued, update the status */ buf->pos = 0; buf->queued = 1; buf->size = vb2_plane_size(q->bufs[index], 0); fileio->q_count += 1; /* * If we are queuing up buffers for the first time, then * increase initial_index by one. */ if (fileio->initial_index < q->num_buffers) fileio->initial_index++; /* * The next buffer to use is either a buffer that's going to be * queued for the first time (initial_index < q->num_buffers) * or it is equal to q->num_buffers, meaning that the next * time we need to dequeue a buffer since we've now queued up * all the 'first time' buffers. */ fileio->cur_index = fileio->initial_index; } /* * Return proper number of bytes processed. */ if (ret == 0) ret = count; return ret; } size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count, loff_t *ppos, int nonblocking) { return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 1); } EXPORT_SYMBOL_GPL(vb2_read); size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count, loff_t *ppos, int nonblocking) { return __vb2_perform_fileio(q, (char __user *) data, count, ppos, nonblocking, 0); } EXPORT_SYMBOL_GPL(vb2_write); struct vb2_threadio_data { struct task_struct *thread; vb2_thread_fnc fnc; void *priv; bool stop; }; static int vb2_thread(void *data) { struct vb2_queue *q = data; struct vb2_threadio_data *threadio = q->threadio; struct vb2_fileio_data *fileio = q->fileio; bool set_timestamp = false; int prequeue = 0; int index = 0; int ret = 0; if (q->is_output) { prequeue = q->num_buffers; set_timestamp = (q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) == V4L2_BUF_FLAG_TIMESTAMP_COPY; } set_freezable(); for (;;) { struct vb2_buffer *vb; /* * Call vb2_dqbuf to get buffer back. */ memset(&fileio->b, 0, sizeof(fileio->b)); fileio->b.type = q->type; fileio->b.memory = q->memory; if (prequeue) { fileio->b.index = index++; prequeue--; } else { call_void_qop(q, wait_finish, q); if (!threadio->stop) ret = vb2_internal_dqbuf(q, &fileio->b, 0); call_void_qop(q, wait_prepare, q); dprintk(5, "file io: vb2_dqbuf result: %d\n", ret); } if (ret || threadio->stop) break; try_to_freeze(); vb = q->bufs[fileio->b.index]; if (!(fileio->b.flags & V4L2_BUF_FLAG_ERROR)) if (threadio->fnc(vb, threadio->priv)) break; call_void_qop(q, wait_finish, q); if (set_timestamp) v4l2_get_timestamp(&fileio->b.timestamp); if (!threadio->stop) ret = vb2_internal_qbuf(q, &fileio->b); call_void_qop(q, wait_prepare, q); if (ret || threadio->stop) break; } /* Hmm, linux becomes *very* unhappy without this ... */ while (!kthread_should_stop()) { set_current_state(TASK_INTERRUPTIBLE); schedule(); } return 0; } /* * 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 mailinglist first. */ int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv, const char *thread_name) { struct vb2_threadio_data *threadio; int ret = 0; if (q->threadio) return -EBUSY; if (vb2_is_busy(q)) return -EBUSY; if (WARN_ON(q->fileio)) return -EBUSY; threadio = kzalloc(sizeof(*threadio), GFP_KERNEL); if (threadio == NULL) return -ENOMEM; threadio->fnc = fnc; threadio->priv = priv; ret = __vb2_init_fileio(q, !q->is_output); dprintk(3, "file io: vb2_init_fileio result: %d\n", ret); if (ret) goto nomem; q->threadio = threadio; threadio->thread = kthread_run(vb2_thread, q, "vb2-%s", thread_name); if (IS_ERR(threadio->thread)) { ret = PTR_ERR(threadio->thread); threadio->thread = NULL; goto nothread; } return 0; nothread: __vb2_cleanup_fileio(q); nomem: kfree(threadio); return ret; } EXPORT_SYMBOL_GPL(vb2_thread_start); int vb2_thread_stop(struct vb2_queue *q) { struct vb2_threadio_data *threadio = q->threadio; int err; if (threadio == NULL) return 0; threadio->stop = true; /* Wake up all pending sleeps in the thread */ vb2_queue_error(q); err = kthread_stop(threadio->thread); __vb2_cleanup_fileio(q); threadio->thread = NULL; kfree(threadio); q->threadio = NULL; return err; } EXPORT_SYMBOL_GPL(vb2_thread_stop); /* * The following functions are not part of the vb2 core API, but are helper * functions that plug into struct v4l2_ioctl_ops, struct v4l2_file_operations * and struct vb2_ops. * They contain boilerplate code that most if not all drivers have to do * and so they simplify the driver code. */ /* The queue is busy if there is a owner and you are not that owner. */ static inline bool vb2_queue_is_busy(struct video_device *vdev, struct file *file) { return vdev->queue->owner && vdev->queue->owner != file->private_data; } /* vb2 ioctl helpers */ int vb2_ioctl_reqbufs(struct file *file, void *priv, struct v4l2_requestbuffers *p) { struct video_device *vdev = video_devdata(file); int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type); if (res) return res; if (vb2_queue_is_busy(vdev, file)) return -EBUSY; res = vb2_core_reqbufs(vdev->queue, p->memory, &p->count); /* If count == 0, then the owner has released all buffers and he is no longer owner of the queue. Otherwise we have a new owner. */ if (res == 0) vdev->queue->owner = p->count ? file->private_data : NULL; return res; } EXPORT_SYMBOL_GPL(vb2_ioctl_reqbufs); int vb2_ioctl_create_bufs(struct file *file, void *priv, struct v4l2_create_buffers *p) { struct video_device *vdev = video_devdata(file); int res = vb2_verify_memory_type(vdev->queue, p->memory, p->format.type); p->index = vdev->queue->num_buffers; /* * If count == 0, then just check if memory and type are valid. * Any -EBUSY result from vb2_verify_memory_type can be mapped to 0. */ if (p->count == 0) return res != -EBUSY ? res : 0; if (res) return res; if (vb2_queue_is_busy(vdev, file)) return -EBUSY; res = vb2_core_create_bufs(vdev->queue, p->memory, &p->count, &p->format); if (res == 0) vdev->queue->owner = file->private_data; return res; } EXPORT_SYMBOL_GPL(vb2_ioctl_create_bufs); int vb2_ioctl_prepare_buf(struct file *file, void *priv, struct v4l2_buffer *p) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_prepare_buf(vdev->queue, p); } EXPORT_SYMBOL_GPL(vb2_ioctl_prepare_buf); int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p) { struct video_device *vdev = video_devdata(file); /* No need to call vb2_queue_is_busy(), anyone can query buffers. */ return vb2_querybuf(vdev->queue, p); } EXPORT_SYMBOL_GPL(vb2_ioctl_querybuf); int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_qbuf(vdev->queue, p); } EXPORT_SYMBOL_GPL(vb2_ioctl_qbuf); int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_dqbuf(vdev->queue, p, file->f_flags & O_NONBLOCK); } EXPORT_SYMBOL_GPL(vb2_ioctl_dqbuf); int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_streamon(vdev->queue, i); } EXPORT_SYMBOL_GPL(vb2_ioctl_streamon); int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_streamoff(vdev->queue, i); } EXPORT_SYMBOL_GPL(vb2_ioctl_streamoff); int vb2_ioctl_expbuf(struct file *file, void *priv, struct v4l2_exportbuffer *p) { struct video_device *vdev = video_devdata(file); if (vb2_queue_is_busy(vdev, file)) return -EBUSY; return vb2_expbuf(vdev->queue, p); } EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf); /* v4l2_file_operations helpers */ int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma) { struct video_device *vdev = video_devdata(file); return vb2_mmap(vdev->queue, vma); } EXPORT_SYMBOL_GPL(vb2_fop_mmap); int _vb2_fop_release(struct file *file, struct mutex *lock) { struct video_device *vdev = video_devdata(file); if (lock) mutex_lock(lock); if (file->private_data == vdev->queue->owner) { vb2_queue_release(vdev->queue); vdev->queue->owner = NULL; } if (lock) mutex_unlock(lock); return v4l2_fh_release(file); } EXPORT_SYMBOL_GPL(_vb2_fop_release); int vb2_fop_release(struct file *file) { struct video_device *vdev = video_devdata(file); struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock; return _vb2_fop_release(file, lock); } EXPORT_SYMBOL_GPL(vb2_fop_release); ssize_t vb2_fop_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct video_device *vdev = video_devdata(file); struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock; int err = -EBUSY; if (!(vdev->queue->io_modes & VB2_WRITE)) return -EINVAL; if (lock && mutex_lock_interruptible(lock)) return -ERESTARTSYS; if (vb2_queue_is_busy(vdev, file)) goto exit; err = vb2_write(vdev->queue, buf, count, ppos, file->f_flags & O_NONBLOCK); if (vdev->queue->fileio) vdev->queue->owner = file->private_data; exit: if (lock) mutex_unlock(lock); return err; } EXPORT_SYMBOL_GPL(vb2_fop_write); ssize_t vb2_fop_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct video_device *vdev = video_devdata(file); struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock; int err = -EBUSY; if (!(vdev->queue->io_modes & VB2_READ)) return -EINVAL; if (lock && mutex_lock_interruptible(lock)) return -ERESTARTSYS; if (vb2_queue_is_busy(vdev, file)) goto exit; err = vb2_read(vdev->queue, buf, count, ppos, file->f_flags & O_NONBLOCK); if (vdev->queue->fileio) vdev->queue->owner = file->private_data; exit: if (lock) mutex_unlock(lock); return err; } EXPORT_SYMBOL_GPL(vb2_fop_read); unsigned int vb2_fop_poll(struct file *file, poll_table *wait) { struct video_device *vdev = video_devdata(file); struct vb2_queue *q = vdev->queue; struct mutex *lock = q->lock ? q->lock : vdev->lock; unsigned res; void *fileio; /* * If this helper doesn't know how to lock, then you shouldn't be using * it but you should write your own. */ WARN_ON(!lock); if (lock && mutex_lock_interruptible(lock)) return POLLERR; fileio = q->fileio; res = vb2_poll(vdev->queue, file, wait); /* If fileio was started, then we have a new queue owner. */ if (!fileio && q->fileio) q->owner = file->private_data; if (lock) mutex_unlock(lock); return res; } EXPORT_SYMBOL_GPL(vb2_fop_poll); #ifndef CONFIG_MMU unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct video_device *vdev = video_devdata(file); return vb2_get_unmapped_area(vdev->queue, addr, len, pgoff, flags); } EXPORT_SYMBOL_GPL(vb2_fop_get_unmapped_area); #endif /* vb2_ops helpers. Only use if vq->lock is non-NULL. */ void vb2_ops_wait_prepare(struct vb2_queue *vq) { mutex_unlock(vq->lock); } EXPORT_SYMBOL_GPL(vb2_ops_wait_prepare); void vb2_ops_wait_finish(struct vb2_queue *vq) { mutex_lock(vq->lock); } EXPORT_SYMBOL_GPL(vb2_ops_wait_finish); MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2"); MODULE_AUTHOR("Pawel Osciak , Marek Szyprowski"); MODULE_LICENSE("GPL");