Split UVC gadget into a library and test application

Split the project into a UVC gadget library and a test application. To
avoid rolling out a custom build system, switch to CMake.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 833 insertions, 0 deletions

diff --git a/lib/v4l2.c b/lib/v4l2.c
new file mode 100644
index 0000000..9030270
--- /dev/null
+++ b/lib/v4l2.c
@@ -0,0 +1,833 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * V4L2 Devices
+ *
+ * Copyright (C) 2018 Laurent Pinchart
+ *
+ * This file originally comes from the omap3-isp-live project
+ * (git://git.ideasonboard.org/omap3-isp-live.git)
+ *
+ * Copyright (C) 2010-2011 Ideas on board SPRL
+ *
+ * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <linux/videodev2.h>
+
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/select.h>
+#include <sys/time.h>
+
+#include "list.h"
+#include "tools.h"
+#include "v4l2.h"
+#include "video-buffers.h"
+
+#ifndef V4L2_BUF_FLAG_ERROR
+#define V4L2_BUF_FLAG_ERROR	0x0040
+#endif
+
+struct v4l2_ival_desc {
+	struct v4l2_fract min;
+	struct v4l2_fract max;
+	struct v4l2_fract step;
+
+	struct list_entry list;
+};
+
+struct v4l2_frame_desc {
+	unsigned int min_width;
+	unsigned int min_height;
+	unsigned int max_width;
+	unsigned int max_height;
+	unsigned int step_width;
+	unsigned int step_height;
+
+	struct list_entry list;
+	struct list_entry ivals;
+};
+
+struct v4l2_format_desc {
+	unsigned int pixelformat;
+
+	struct list_entry list;
+	struct list_entry frames;
+};
+
+/* -----------------------------------------------------------------------------
+ * Formats enumeration
+ */
+
+static int
+v4l2_enum_frame_intervals(struct v4l2_device *dev, struct v4l2_format_desc *format,
+	struct v4l2_frame_desc *frame)
+{
+	struct v4l2_ival_desc *ival;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; ; ++i) {
+		struct v4l2_frmivalenum ivalenum;
+
+		memset(&ivalenum, 0, sizeof ivalenum);
+		ivalenum.index = i;
+		ivalenum.pixel_format = format->pixelformat;
+		ivalenum.width = frame->min_width;
+		ivalenum.height = frame->min_height;
+		ret = ioctl(dev->fd, VIDIOC_ENUM_FRAMEINTERVALS, &ivalenum);
+		if (ret < 0)
+			break;
+
+		if (i != ivalenum.index)
+			printf("Warning: driver returned wrong ival index "
+				"%u.\n", ivalenum.index);
+		if (format->pixelformat != ivalenum.pixel_format)
+			printf("Warning: driver returned wrong ival pixel "
+				"format %08x.\n", ivalenum.pixel_format);
+		if (frame->min_width != ivalenum.width)
+			printf("Warning: driver returned wrong ival width "
+				"%u.\n", ivalenum.width);
+		if (frame->min_height != ivalenum.height)
+			printf("Warning: driver returned wrong ival height "
+				"%u.\n", ivalenum.height);
+
+		ival = malloc(sizeof *ival);
+		if (ival == NULL)
+			return -ENOMEM;
+
+		memset(ival, 0, sizeof *ival);
+
+		switch (ivalenum.type) {
+		case V4L2_FRMIVAL_TYPE_DISCRETE:
+			ival->min = ivalenum.discrete;
+			ival->max = ivalenum.discrete;
+			ival->step.numerator = 1;
+			ival->step.denominator = 1;
+			break;
+
+		case V4L2_FRMIVAL_TYPE_STEPWISE:
+			ival->min = ivalenum.stepwise.min;
+			ival->max = ivalenum.stepwise.max;
+			ival->step = ivalenum.stepwise.step;
+			break;
+
+		default:
+			printf("Error: driver returned invalid frame ival "
+				"type %u\n", ivalenum.type);
+			return -EINVAL;
+		}
+
+		list_append(&ival->list, &frame->ivals);
+	}
+
+	return 0;
+}
+
+static int
+v4l2_enum_frame_sizes(struct v4l2_device *dev, struct v4l2_format_desc *format)
+{
+	struct v4l2_frame_desc *frame;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; ; ++i) {
+		struct v4l2_frmsizeenum frmenum;
+
+		memset(&frmenum, 0, sizeof frmenum);
+		frmenum.index = i;
+		frmenum.pixel_format = format->pixelformat;
+
+		ret = ioctl(dev->fd, VIDIOC_ENUM_FRAMESIZES, &frmenum);
+		if (ret < 0)
+			break;
+
+		if (i != frmenum.index)
+			printf("Warning: driver returned wrong frame index "
+				"%u.\n", frmenum.index);
+		if (format->pixelformat != frmenum.pixel_format)
+			printf("Warning: driver returned wrong frame pixel "
+				"format %08x.\n", frmenum.pixel_format);
+
+		frame = malloc(sizeof *frame);
+		if (frame == NULL)
+			return -ENOMEM;
+
+		memset(frame, 0, sizeof *frame);
+
+		list_init(&frame->ivals);
+		frame->step_width = 1;
+		frame->step_height = 1;
+
+		switch (frmenum.type) {
+		case V4L2_FRMSIZE_TYPE_DISCRETE:
+			frame->min_width = frmenum.discrete.width;
+			frame->min_height = frmenum.discrete.height;
+			frame->max_width = frmenum.discrete.width;
+			frame->max_height = frmenum.discrete.height;
+			break;
+
+		case V4L2_FRMSIZE_TYPE_STEPWISE:
+			frame->step_width = frmenum.stepwise.step_width;
+			frame->step_height = frmenum.stepwise.step_height;
+			/* fallthrough */
+		case V4L2_FRMSIZE_TYPE_CONTINUOUS:
+			frame->min_width = frmenum.stepwise.min_width;
+			frame->min_height = frmenum.stepwise.min_height;
+			frame->max_width = frmenum.stepwise.max_width;
+			frame->max_height = frmenum.stepwise.max_height;
+			break;
+
+		default:
+			printf("Error: driver returned invalid frame size "
+				"type %u\n", frmenum.type);
+			return -EINVAL;
+		}
+
+		list_append(&frame->list, &format->frames);
+
+		ret = v4l2_enum_frame_intervals(dev, format, frame);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+static int v4l2_enum_formats(struct v4l2_device *dev)
+{
+	struct v4l2_format_desc *format;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; ; ++i) {
+		struct v4l2_fmtdesc fmtenum;
+
+		memset(&fmtenum, 0, sizeof fmtenum);
+		fmtenum.index = i;
+		fmtenum.type = dev->type;
+
+		ret = ioctl(dev->fd, VIDIOC_ENUM_FMT, &fmtenum);
+		if (ret < 0)
+			break;
+
+		if (i != fmtenum.index)
+			printf("Warning: driver returned wrong format index "
+				"%u.\n", fmtenum.index);
+		if (dev->type != fmtenum.type)
+			printf("Warning: driver returned wrong format type "
+				"%u.\n", fmtenum.type);
+
+		format = malloc(sizeof *format);
+		if (format == NULL)
+			return -ENOMEM;
+
+		memset(format, 0, sizeof *format);
+
+		list_init(&format->frames);
+		format->pixelformat = fmtenum.pixelformat;
+
+		list_append(&format->list, &dev->formats);
+
+		ret = v4l2_enum_frame_sizes(dev, format);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Open/close
+ */
+
+struct v4l2_device *v4l2_open(const char *devname)
+{
+	struct v4l2_device *dev;
+	struct v4l2_capability cap;
+	__u32 capabilities;
+	int ret;
+
+	dev = malloc(sizeof *dev);
+	if (dev == NULL)
+		return NULL;
+
+	memset(dev, 0, sizeof *dev);
+	dev->fd = -1;
+	dev->name = strdup(devname);
+	list_init(&dev->formats);
+
+	dev->fd = open(devname, O_RDWR | O_NONBLOCK);
+	if (dev->fd < 0) {
+		printf("Error opening device %s: %d.\n", devname, errno);
+		v4l2_close(dev);
+		return NULL;
+	}
+
+	memset(&cap, 0, sizeof cap);
+	ret = ioctl(dev->fd, VIDIOC_QUERYCAP, &cap);
+	if (ret < 0) {
+		printf("Error opening device %s: unable to query "
+			"device.\n", devname);
+		v4l2_close(dev);
+		return NULL;
+	}
+
+	/* 
+	 * If the device_caps field is set use it, otherwise use the older
+	 * capabilities field.
+	 */
+	capabilities = cap.device_caps ? : cap.capabilities;
+
+	if (capabilities & V4L2_CAP_VIDEO_CAPTURE)
+		dev->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	else if (capabilities & V4L2_CAP_VIDEO_OUTPUT)
+		dev->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
+	else {
+		printf("Error opening device %s: neither video capture "
+			"nor video output supported.\n", devname);
+		v4l2_close(dev);
+		return NULL;
+	}
+
+	ret = v4l2_enum_formats(dev);
+	if (ret < 0) {
+		printf("Error opening device %s: unable to enumerate "
+			"formats.\n", devname);
+		v4l2_close(dev);
+		return NULL;
+	}
+
+	printf("Device %s opened: %s (%s).\n", devname, cap.card, cap.bus_info);
+
+	return dev;
+}
+
+void v4l2_close(struct v4l2_device *dev)
+{
+	struct v4l2_format_desc *format, *next_fmt;
+	struct v4l2_frame_desc *frame, *next_frm;
+	struct v4l2_ival_desc *ival, *next_ival;
+
+	if (dev == NULL)
+		return;
+
+	list_for_each_entry_safe(format, next_fmt, &dev->formats, list) {
+		list_for_each_entry_safe(frame, next_frm, &format->frames, list) {
+			list_for_each_entry_safe(ival, next_ival, &frame->ivals, list) {
+				free(ival);
+			}
+			free(frame);
+		}
+		free(format);
+	}
+
+	free(dev->name);
+	close(dev->fd);
+	free(dev);
+}
+
+/* -----------------------------------------------------------------------------
+ * Controls
+ */
+
+int v4l2_get_control(struct v4l2_device *dev, unsigned int id, int32_t *value)
+{
+	struct v4l2_control ctrl;
+	int ret;
+
+	ctrl.id = id;
+
+	ret = ioctl(dev->fd, VIDIOC_G_CTRL, &ctrl);
+	if (ret < 0) {
+		printf("%s: unable to get control (%d).\n", dev->name, errno);
+		return -errno;
+	}
+
+	*value = ctrl.value;
+	return 0;
+}
+
+int v4l2_set_control(struct v4l2_device *dev, unsigned int id, int32_t *value)
+{
+	struct v4l2_control ctrl;
+	int ret;
+
+	ctrl.id = id;
+	ctrl.value = *value;
+
+	ret = ioctl(dev->fd, VIDIOC_S_CTRL, &ctrl);
+	if (ret < 0) {
+		printf("%s: unable to set control (%d).\n", dev->name, errno);
+		return -errno;
+	}
+
+	*value = ctrl.value;
+	return 0;
+}
+
+int v4l2_get_controls(struct v4l2_device *dev, unsigned int count,
+		      struct v4l2_ext_control *ctrls)
+{
+	struct v4l2_ext_controls controls;
+	int ret;
+
+	memset(&controls, 0, sizeof controls);
+	controls.count = count;
+	controls.controls = ctrls;
+
+	ret = ioctl(dev->fd, VIDIOC_G_EXT_CTRLS, &controls);
+	if (ret < 0)
+		printf("%s: unable to get multiple controls (%d).\n", dev->name,
+		       errno);
+
+	return ret;
+}
+
+int v4l2_set_controls(struct v4l2_device *dev, unsigned int count,
+		      struct v4l2_ext_control *ctrls)
+{
+	struct v4l2_ext_controls controls;
+	int ret;
+
+	memset(&controls, 0, sizeof controls);
+	controls.count = count;
+	controls.controls = ctrls;
+
+	ret = ioctl(dev->fd, VIDIOC_S_EXT_CTRLS, &controls);
+	if (ret < 0)
+		printf("%s: unable to set multiple controls (%d).\n", dev->name,
+		       errno);
+
+	return ret;
+}
+
+/* -----------------------------------------------------------------------------
+ * Formats and frame rates
+ */
+
+int v4l2_get_crop(struct v4l2_device *dev, struct v4l2_rect *rect)
+{
+	struct v4l2_crop crop;
+	int ret;
+
+	memset(&crop, 0, sizeof crop);
+	crop.type = dev->type;
+
+	ret = ioctl(dev->fd, VIDIOC_G_CROP, &crop);
+	if (ret < 0) {
+		printf("%s: unable to get crop rectangle (%d).\n", dev->name,
+		       errno);
+		return -errno;
+	}
+
+	dev->crop = crop.c;
+	*rect = crop.c;
+
+	return 0;
+}
+
+int v4l2_set_crop(struct v4l2_device *dev, struct v4l2_rect *rect)
+{
+	struct v4l2_crop crop;
+	int ret;
+
+	memset(&crop, 0, sizeof crop);
+	crop.type = dev->type;
+	crop.c = *rect;
+
+	ret = ioctl(dev->fd, VIDIOC_S_CROP, &crop);
+	if (ret < 0) {
+		printf("%s: unable to set crop rectangle (%d).\n", dev->name,
+		       errno);
+		return -errno;
+	}
+
+	dev->crop = crop.c;
+	*rect = crop.c;
+
+	return 0;
+}
+
+int v4l2_get_format(struct v4l2_device *dev, struct v4l2_pix_format *format)
+{
+	struct v4l2_format fmt;
+	int ret;
+
+	memset(&fmt, 0, sizeof fmt);
+	fmt.type = dev->type;
+
+	ret = ioctl(dev->fd, VIDIOC_G_FMT, &fmt);
+	if (ret < 0) {
+		printf("%s: unable to get format (%d).\n", dev->name, errno);
+		return -errno;
+	}
+
+	dev->format = fmt.fmt.pix;
+	*format = fmt.fmt.pix;
+
+	return 0;
+}
+
+int v4l2_set_format(struct v4l2_device *dev, struct v4l2_pix_format *format)
+{
+	struct v4l2_format fmt;
+	int ret;
+
+	memset(&fmt, 0, sizeof fmt);
+	fmt.type = dev->type;
+	fmt.fmt.pix.width = format->width;
+	fmt.fmt.pix.height = format->height;
+	fmt.fmt.pix.pixelformat = format->pixelformat;
+	fmt.fmt.pix.field = V4L2_FIELD_ANY;
+
+	ret = ioctl(dev->fd, VIDIOC_S_FMT, &fmt);
+	if (ret < 0) {
+		printf("%s: unable to set format (%d).\n", dev->name, errno);
+		return -errno;
+	}
+
+	dev->format = fmt.fmt.pix;
+	*format = fmt.fmt.pix;
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Buffers management
+ */
+
+int v4l2_alloc_buffers(struct v4l2_device *dev, enum v4l2_memory memtype,
+		       unsigned int nbufs)
+{
+	struct v4l2_requestbuffers rb;
+	unsigned int i;
+	int ret;
+
+	if (dev->buffers.nbufs != 0)
+		return -EBUSY;
+
+	if (memtype != V4L2_MEMORY_MMAP && memtype != V4L2_MEMORY_DMABUF)
+		return -EINVAL;
+
+	/* Request the buffers from the driver. */
+	memset(&rb, 0, sizeof rb);
+	rb.count = nbufs;
+	rb.type = dev->type;
+	rb.memory = memtype;
+
+	ret = ioctl(dev->fd, VIDIOC_REQBUFS, &rb);
+	if (ret < 0) {
+		printf("%s: unable to request buffers (%d).\n", dev->name,
+		       errno);
+		ret = -errno;
+		goto done;
+	}
+
+	if (rb.count > nbufs) {
+		printf("%s: driver needs more buffers (%u) than available (%u).\n",
+		       dev->name, rb.count, nbufs);
+		ret = -E2BIG;
+		goto done;
+	}
+
+	printf("%s: %u buffers requested.\n", dev->name, rb.count);
+
+	/* Allocate the buffer objects. */
+	dev->memtype = memtype;
+	dev->buffers.nbufs = rb.count;
+
+	dev->buffers.buffers = calloc(nbufs, sizeof *dev->buffers.buffers);
+	if (dev->buffers.buffers == NULL) {
+		ret = -ENOMEM;
+		goto done;
+	}
+
+	for (i = 0; i < dev->buffers.nbufs; ++i) {
+		dev->buffers.buffers[i].index = i;
+		dev->buffers.buffers[i].dmabuf = -1;
+	}
+
+	ret = 0;
+
+done:
+	if (ret < 0)
+		v4l2_free_buffers(dev);
+
+	return ret;
+}
+
+int v4l2_free_buffers(struct v4l2_device *dev)
+{
+	struct v4l2_requestbuffers rb;
+	unsigned int i;
+	int ret;
+
+	if (dev->buffers.nbufs == 0)
+		return 0;
+
+	for (i = 0; i < dev->buffers.nbufs; ++i) {
+		struct video_buffer *buffer = &dev->buffers.buffers[i];
+
+		if (buffer->mem) {
+			ret = munmap(buffer->mem, buffer->size);
+			if (ret < 0) {
+				printf("%s: unable to unmap buffer %u (%d)\n",
+				       dev->name, i, errno);
+				return -errno;
+			}
+
+			buffer->mem = NULL;
+		}
+
+		if (buffer->dmabuf != -1) {
+			close(buffer->dmabuf);
+			buffer->dmabuf = -1;
+		}
+
+		buffer->size = 0;
+	}
+
+	memset(&rb, 0, sizeof rb);
+	rb.count = 0;
+	rb.type = dev->type;
+	rb.memory = dev->memtype;
+
+	ret = ioctl(dev->fd, VIDIOC_REQBUFS, &rb);
+	if (ret < 0) {
+		printf("%s: unable to release buffers (%d)\n", dev->name,
+		       errno);
+		return -errno;
+	}
+
+	free(dev->buffers.buffers);
+	dev->buffers.buffers = NULL;
+	dev->buffers.nbufs = 0;
+
+	return 0;
+}
+
+int v4l2_export_buffers(struct v4l2_device *dev)
+{
+	unsigned int i;
+	int ret;
+
+	if (dev->buffers.nbufs == 0)
+		return -EINVAL;
+
+	if (dev->memtype != V4L2_MEMORY_MMAP)
+		return -EINVAL;
+
+	for (i = 0; i < dev->buffers.nbufs; ++i) {
+		struct v4l2_exportbuffer expbuf = {
+			.type = dev->type,
+			.index = i,
+		};
+		struct v4l2_buffer buf = {
+			.index = i,
+			.type = dev->type,
+			.memory = dev->memtype,
+		};
+
+		ret = ioctl(dev->fd, VIDIOC_QUERYBUF, &buf);
+		if (ret < 0) {
+			printf("%s: unable to query buffer %u (%d).\n",
+			       dev->name, i, errno);
+			return -errno;
+		}
+
+		ret = ioctl(dev->fd, VIDIOC_EXPBUF, &expbuf);
+		if (ret < 0) {
+			printf("Failed to export buffer %u.\n", i);
+			return -errno;
+		}
+
+		dev->buffers.buffers[i].size = buf.length;
+		dev->buffers.buffers[i].dmabuf = expbuf.fd;
+
+		printf("%s: buffer %u exported with fd %u.\n",
+		       dev->name, i, dev->buffers.buffers[i].dmabuf);
+	}
+
+	return 0;
+}
+
+int v4l2_import_buffers(struct v4l2_device *dev,
+			const struct video_buffer_set *buffers)
+{
+	unsigned int i;
+	int ret;
+
+	if (dev->buffers.nbufs == 0 || dev->buffers.nbufs > buffers->nbufs)
+		return -EINVAL;
+
+	if (dev->memtype != V4L2_MEMORY_DMABUF)
+		return -EINVAL;
+
+	for (i = 0; i < dev->buffers.nbufs; ++i) {
+		const struct video_buffer *buffer = &buffers->buffers[i];
+		struct v4l2_buffer buf = {
+			.index = i,
+			.type = dev->type,
+			.memory = dev->memtype,
+		};
+		int fd;
+
+		ret = ioctl(dev->fd, VIDIOC_QUERYBUF, &buf);
+		if (ret < 0) {
+			printf("%s: unable to query buffer %u (%d).\n",
+			       dev->name, i, errno);
+			return -errno;
+		}
+
+		if (buffer->size < buf.length) {
+			printf("%s: buffer %u too small (%u bytes required, %u bytes available).\n",
+			       dev->name, i, buf.length, buffer->size);
+			return -EINVAL;
+		}
+
+		fd = dup(buffer->dmabuf);
+		if (fd < 0) {
+			printf("%s: failed to duplicate dmabuf fd %d.\n",
+			       dev->name, buffer->dmabuf);
+			return ret;
+		}
+
+		printf("%s: buffer %u valid.\n", dev->name, i);
+
+		dev->buffers.buffers[i].dmabuf = fd;
+		dev->buffers.buffers[i].size = buffer->size;
+	}
+
+	return 0;
+}
+
+int v4l2_mmap_buffers(struct v4l2_device *dev)
+{
+	unsigned int i;
+	int ret;
+
+	if (dev->memtype != V4L2_MEMORY_MMAP)
+		return -EINVAL;
+
+	for (i = 0; i < dev->buffers.nbufs; ++i) {
+		struct video_buffer *buffer = &dev->buffers.buffers[i];
+		struct v4l2_buffer buf = {
+			.index = i,
+			.type = dev->type,
+			.memory = dev->memtype,
+		};
+		void *mem;
+
+		ret = ioctl(dev->fd, VIDIOC_QUERYBUF, &buf);
+		if (ret < 0) {
+			printf("%s: unable to query buffer %u (%d).\n",
+			       dev->name, i, errno);
+			return -errno;
+		}
+
+		mem = mmap(0, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED,
+			   dev->fd, buf.m.offset);
+		if (mem == MAP_FAILED) {
+			printf("%s: unable to map buffer %u (%d)\n",
+			       dev->name, i, errno);
+			return -errno;
+		}
+
+		buffer->mem = mem;
+		buffer->size = buf.length;
+
+		printf("%s: buffer %u mapped at address %p.\n", dev->name, i,
+		       mem);
+	}
+
+	return 0;
+}
+
+int v4l2_dequeue_buffer(struct v4l2_device *dev, struct video_buffer *buffer)
+{
+	struct v4l2_buffer buf;
+	int ret;
+
+	memset(&buf, 0, sizeof buf);
+	buf.type = dev->type;
+	buf.memory = dev->memtype;
+
+	ret = ioctl(dev->fd, VIDIOC_DQBUF, &buf);
+	if (ret < 0) {
+		printf("%s: unable to dequeue buffer index %u/%u (%d)\n",
+		       dev->name, buf.index, dev->buffers.nbufs, errno);
+		return -errno;
+	}
+
+	buffer->index = buf.index;
+	buffer->bytesused = buf.bytesused;
+	buffer->timestamp = buf.timestamp;
+	buffer->error = !!(buf.flags & V4L2_BUF_FLAG_ERROR);
+
+	return 0;
+}
+
+int v4l2_queue_buffer(struct v4l2_device *dev, struct video_buffer *buffer)
+{
+	struct v4l2_buffer buf;
+	int ret;
+
+	if (buffer->index >= dev->buffers.nbufs)
+		return -EINVAL;
+
+	memset(&buf, 0, sizeof buf);
+	buf.index = buffer->index;
+	buf.type = dev->type;
+	buf.memory = dev->memtype;
+
+	if (dev->memtype == V4L2_MEMORY_DMABUF)
+		buf.m.fd = (unsigned long)dev->buffers.buffers[buffer->index].dmabuf;
+
+	if (dev->type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
+		buf.bytesused = buffer->bytesused;
+
+	ret = ioctl(dev->fd, VIDIOC_QBUF, &buf);
+	if (ret < 0) {
+		printf("%s: unable to queue buffer index %u/%u (%d)\n",
+		       dev->name, buf.index, dev->buffers.nbufs, errno);
+		return -errno;
+	}
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Stream management
+ */
+
+int v4l2_stream_on(struct v4l2_device *dev)
+{
+	int type = dev->type;
+	int ret;
+
+	ret = ioctl(dev->fd, VIDIOC_STREAMON, &type);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}
+
+int v4l2_stream_off(struct v4l2_device *dev)
+{
+	int type = dev->type;
+	int ret;
+
+	ret = ioctl(dev->fd, VIDIOC_STREAMOFF, &type);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}