virtualization: Add virtio-video driver as external module.

This driver should conform WIP spec v3 [1] with some updates for spec v4
[2], and, some unspecified features such as VIRTIO_VIDEO_DEVICE_CAMERA.

Imported from internal OpenSynergy's revision:

  bcc33b6b9e0156b381a70c54d2df02c57b63d270

Kernel was configured with necessary features for this driver:

  enable MEDIA_SUPPORT
  disable MEDIA_SUBDRV_AUTOSELECT
  enable MEDIA_PLATFORM_SUPPORT
  enable VIDEO_VIRTIO

Keep driver as an external module to simplify future updates.

[1]: https://lists.oasis-open.org/archives/virtio-dev/202002/msg00002.html
[2]: https://lists.oasis-open.org/archives/virtio-dev/202006/msg00072.html

Bug-AGL: SPEC-4148
Change-Id: Iea339194b22443f67b3e2ffddca84118357a2f15
Signed-off-by: Vasyl Vavrychuk <vasyl.vavrychuk@opensynergy.com>

1 files changed, 601 insertions, 0 deletions

diff --git a/meta-egvirt/recipes-kernel/kernel-module-virtio-video/files/virtio_video_enc.c b/meta-egvirt/recipes-kernel/kernel-module-virtio-video/files/virtio_video_enc.c
new file mode 100644
index 00000000..66730bdb
--- /dev/null
+++ b/meta-egvirt/recipes-kernel/kernel-module-virtio-video/files/virtio_video_enc.c
@@ -0,0 +1,601 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Encoder for virtio video device.
+ *
+ * Copyright 2020 OpenSynergy GmbH.
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/version.h>
+#include <media/v4l2-event.h>
+#include <media/v4l2-ioctl.h>
+
+#include "virtio_video.h"
+
+static int virtio_video_enc_start_streaming(struct vb2_queue *vq,
+					    unsigned int count)
+{
+	struct virtio_video_stream *stream = vb2_get_drv_priv(vq);
+	bool input_queue = V4L2_TYPE_IS_OUTPUT(vq->type);
+
+	if (virtio_video_state(stream) == STREAM_STATE_ERROR)
+		return -EIO;
+
+	if (virtio_video_state(stream) == STREAM_STATE_INIT ||
+	    (!input_queue &&
+	     virtio_video_state(stream) == STREAM_STATE_RESET) ||
+	    (input_queue &&
+	     virtio_video_state(stream) == STREAM_STATE_STOPPED))
+		virtio_video_state_update(stream, STREAM_STATE_RUNNING);
+
+	return 0;
+}
+
+static void virtio_video_enc_stop_streaming(struct vb2_queue *vq)
+{
+	int ret, queue_type;
+	struct virtio_video_stream *stream = vb2_get_drv_priv(vq);
+
+	if (V4L2_TYPE_IS_OUTPUT(vq->type))
+		queue_type = VIRTIO_VIDEO_QUEUE_TYPE_INPUT;
+	else
+		queue_type = VIRTIO_VIDEO_QUEUE_TYPE_OUTPUT;
+
+	ret = virtio_video_queue_release_buffers(stream, queue_type);
+	if (ret)
+		return;
+
+	vb2_wait_for_all_buffers(vq);
+
+	if (V4L2_TYPE_IS_OUTPUT(vq->type))
+		virtio_video_state_update(stream, STREAM_STATE_STOPPED);
+	else
+		virtio_video_state_update(stream, STREAM_STATE_RESET);
+}
+
+static const struct vb2_ops virtio_video_enc_qops = {
+	.queue_setup	 = virtio_video_queue_setup,
+	.buf_init	 = virtio_video_buf_init,
+	.buf_cleanup	 = virtio_video_buf_cleanup,
+	.buf_queue	 = virtio_video_buf_queue,
+	.start_streaming = virtio_video_enc_start_streaming,
+	.stop_streaming  = virtio_video_enc_stop_streaming,
+	.wait_prepare	 = vb2_ops_wait_prepare,
+	.wait_finish	 = vb2_ops_wait_finish,
+};
+
+static int virtio_video_enc_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	int ret = 0;
+	struct virtio_video_stream *stream = ctrl2stream(ctrl);
+	struct virtio_video_device *vvd = to_virtio_vd(stream->video_dev);
+	uint32_t control, value;
+
+	if (virtio_video_state(stream) == STREAM_STATE_ERROR)
+		return -EIO;
+
+	control = virtio_video_v4l2_control_to_virtio(ctrl->id);
+
+	switch (ctrl->id) {
+	case V4L2_CID_MPEG_VIDEO_BITRATE:
+		ret = virtio_video_cmd_set_control(vvd, stream->stream_id,
+						   control, ctrl->val);
+		break;
+	case V4L2_CID_MPEG_VIDEO_H264_LEVEL:
+		value = virtio_video_v4l2_level_to_virtio(ctrl->val);
+		ret = virtio_video_cmd_set_control(vvd, stream->stream_id,
+						   control, value);
+		break;
+	case V4L2_CID_MPEG_VIDEO_H264_PROFILE:
+		value = virtio_video_v4l2_profile_to_virtio(ctrl->val);
+		ret = virtio_video_cmd_set_control(vvd, stream->stream_id,
+						   control, value);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static int virtio_video_enc_g_ctrl(struct v4l2_ctrl *ctrl)
+{
+	int ret = 0;
+	struct virtio_video_stream *stream = ctrl2stream(ctrl);
+
+	if (virtio_video_state(stream) == STREAM_STATE_ERROR)
+		return -EIO;
+
+	switch (ctrl->id) {
+	case V4L2_CID_MIN_BUFFERS_FOR_OUTPUT:
+		if (virtio_video_state(stream) >= STREAM_STATE_INIT)
+			ctrl->val = stream->in_info.min_buffers;
+		else
+			ctrl->val = 0;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static const struct v4l2_ctrl_ops virtio_video_enc_ctrl_ops = {
+	.g_volatile_ctrl	= virtio_video_enc_g_ctrl,
+	.s_ctrl			= virtio_video_enc_s_ctrl,
+};
+
+int virtio_video_enc_init_ctrls(struct virtio_video_stream *stream)
+{
+	struct v4l2_ctrl *ctrl;
+	struct virtio_video_device *vvd = to_virtio_vd(stream->video_dev);
+	struct video_control_format *c_fmt = NULL;
+
+	v4l2_ctrl_handler_init(&stream->ctrl_handler, 1);
+
+	ctrl = v4l2_ctrl_new_std(&stream->ctrl_handler,
+				&virtio_video_enc_ctrl_ops,
+				V4L2_CID_MIN_BUFFERS_FOR_OUTPUT,
+				MIN_BUFS_MIN, MIN_BUFS_MAX, MIN_BUFS_STEP,
+				MIN_BUFS_DEF);
+
+	if (ctrl)
+		ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+
+	list_for_each_entry(c_fmt, &vvd->controls_fmt_list,
+			    controls_list_entry) {
+		switch (c_fmt->format) {
+		case V4L2_PIX_FMT_H264:
+			if (c_fmt->profile)
+				v4l2_ctrl_new_std_menu
+					(&stream->ctrl_handler,
+					 &virtio_video_enc_ctrl_ops,
+					 V4L2_CID_MPEG_VIDEO_H264_PROFILE,
+					 c_fmt->profile->max,
+					 c_fmt->profile->skip_mask,
+					 c_fmt->profile->min);
+
+			if (c_fmt->level)
+				v4l2_ctrl_new_std_menu
+					(&stream->ctrl_handler,
+					 &virtio_video_enc_ctrl_ops,
+					 V4L2_CID_MPEG_VIDEO_H264_LEVEL,
+					 c_fmt->level->max,
+					 c_fmt->level->skip_mask,
+					 c_fmt->level->min);
+			break;
+		default:
+			v4l2_dbg(1, vvd->debug,
+				 &vvd->v4l2_dev, "unsupported format\n");
+			break;
+		}
+	}
+
+	if (stream->control.bitrate) {
+		v4l2_ctrl_new_std(&stream->ctrl_handler,
+				  &virtio_video_enc_ctrl_ops,
+				  V4L2_CID_MPEG_VIDEO_BITRATE,
+				  1, S32_MAX,
+				  1, stream->control.bitrate);
+	}
+
+	if (stream->ctrl_handler.error)
+		return stream->ctrl_handler.error;
+
+	v4l2_ctrl_handler_setup(&stream->ctrl_handler);
+
+	return 0;
+}
+
+int virtio_video_enc_init_queues(void *priv, struct vb2_queue *src_vq,
+				 struct vb2_queue *dst_vq)
+{
+	int ret;
+	struct virtio_video_stream *stream = priv;
+	struct virtio_video_device *vvd = to_virtio_vd(stream->video_dev);
+	struct device *dev = vvd->v4l2_dev.dev;
+
+	src_vq->type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+	src_vq->io_modes = VB2_MMAP | VB2_DMABUF;
+	src_vq->drv_priv = stream;
+	src_vq->buf_struct_size = sizeof(struct virtio_video_buffer);
+	src_vq->ops = &virtio_video_enc_qops;
+	src_vq->mem_ops = virtio_video_mem_ops(vvd);
+	src_vq->min_buffers_needed = stream->in_info.min_buffers;
+	src_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
+	src_vq->lock = &stream->vq_mutex;
+	src_vq->gfp_flags = virtio_video_gfp_flags(vvd);
+	src_vq->dev = dev;
+
+	ret = vb2_queue_init(src_vq);
+	if (ret)
+		return ret;
+
+	dst_vq->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+	dst_vq->io_modes = VB2_MMAP | VB2_DMABUF;
+	dst_vq->drv_priv = stream;
+	dst_vq->buf_struct_size = sizeof(struct virtio_video_buffer);
+	dst_vq->ops = &virtio_video_enc_qops;
+	dst_vq->mem_ops = virtio_video_mem_ops(vvd);
+	dst_vq->min_buffers_needed = stream->out_info.min_buffers;
+	dst_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
+	dst_vq->lock = &stream->vq_mutex;
+	dst_vq->gfp_flags = virtio_video_gfp_flags(vvd);
+	dst_vq->dev = dev;
+
+	return vb2_queue_init(dst_vq);
+}
+
+static int virtio_video_try_encoder_cmd(struct file *file, void *fh,
+					struct v4l2_encoder_cmd *cmd)
+{
+	struct virtio_video_stream *stream = file2stream(file);
+	struct virtio_video_device *vvd = video_drvdata(file);
+
+	if (virtio_video_state(stream) == STREAM_STATE_ERROR)
+		return -EIO;
+
+	if (virtio_video_state(stream) == STREAM_STATE_DRAIN)
+		return -EBUSY;
+
+	switch (cmd->cmd) {
+	case V4L2_ENC_CMD_STOP:
+	case V4L2_ENC_CMD_START:
+		if (cmd->flags != 0) {
+			v4l2_err(&vvd->v4l2_dev, "flags=%u are not supported",
+				 cmd->flags);
+			return -EINVAL;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int virtio_video_encoder_cmd(struct file *file, void *fh,
+				    struct v4l2_encoder_cmd *cmd)
+{
+	int ret;
+	struct vb2_queue *src_vq, *dst_vq;
+	struct virtio_video_stream *stream = file2stream(file);
+	struct virtio_video_device *vvd = video_drvdata(file);
+
+	ret = virtio_video_try_encoder_cmd(file, fh, cmd);
+	if (ret < 0)
+		return ret;
+
+	dst_vq = v4l2_m2m_get_vq(stream->fh.m2m_ctx,
+				 V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
+
+	switch (cmd->cmd) {
+	case V4L2_ENC_CMD_START:
+		vb2_clear_last_buffer_dequeued(dst_vq);
+		virtio_video_state_update(stream, STREAM_STATE_RUNNING);
+		break;
+	case V4L2_ENC_CMD_STOP:
+		src_vq = v4l2_m2m_get_vq(stream->fh.m2m_ctx,
+					 V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE);
+
+		if (!vb2_is_streaming(src_vq)) {
+			v4l2_dbg(1, vvd->debug,
+				 &vvd->v4l2_dev, "output is not streaming\n");
+			return 0;
+		}
+
+		if (!vb2_is_streaming(dst_vq)) {
+			v4l2_dbg(1, vvd->debug,
+				 &vvd->v4l2_dev, "capture is not streaming\n");
+			return 0;
+		}
+
+		ret = virtio_video_cmd_stream_drain(vvd, stream->stream_id);
+		if (ret) {
+			v4l2_err(&vvd->v4l2_dev, "failed to drain stream\n");
+			return ret;
+		}
+
+		virtio_video_state_update(stream, STREAM_STATE_DRAIN);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int virtio_video_enc_enum_fmt_vid_cap(struct file *file, void *fh,
+					     struct v4l2_fmtdesc *f)
+{
+	struct virtio_video_stream *stream = file2stream(file);
+	struct virtio_video_device *vvd = to_virtio_vd(stream->video_dev);
+	struct video_format *fmt;
+	int idx = 0;
+
+	if (virtio_video_state(stream) == STREAM_STATE_ERROR)
+		return -EIO;
+
+	if (f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE)
+		return -EINVAL;
+
+	if (f->index >= vvd->num_output_fmts)
+		return -EINVAL;
+
+	list_for_each_entry(fmt, &vvd->output_fmt_list, formats_list_entry) {
+		if (f->index == idx) {
+			f->pixelformat = fmt->desc.format;
+			return 0;
+		}
+		idx++;
+	}
+	return -EINVAL;
+}
+
+static int virtio_video_enc_enum_fmt_vid_out(struct file *file, void *fh,
+					     struct v4l2_fmtdesc *f)
+{
+	struct virtio_video_stream *stream = file2stream(file);
+	struct virtio_video_device *vvd = to_virtio_vd(stream->video_dev);
+	struct video_format_info *info = NULL;
+	struct video_format *fmt = NULL;
+	unsigned long output_mask = 0;
+	int idx = 0, bit_num = 0;
+
+	if (virtio_video_state(stream) == STREAM_STATE_ERROR)
+		return -EIO;
+
+	if (f->type != V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
+		return -EINVAL;
+
+	if (f->index >= vvd->num_input_fmts)
+		return -EINVAL;
+
+	info = &stream->out_info;
+	list_for_each_entry(fmt, &vvd->output_fmt_list, formats_list_entry) {
+		if (info->fourcc_format == fmt->desc.format) {
+			output_mask = fmt->desc.mask;
+			break;
+		}
+	}
+
+	if (output_mask == 0)
+		return -EINVAL;
+
+	list_for_each_entry(fmt, &vvd->input_fmt_list, formats_list_entry) {
+		if (test_bit(bit_num, &output_mask)) {
+			if (f->index == idx) {
+				f->pixelformat = fmt->desc.format;
+				return 0;
+			}
+			idx++;
+		}
+		bit_num++;
+	}
+	return -EINVAL;
+}
+
+static int virtio_video_enc_s_fmt(struct file *file, void *fh,
+				  struct v4l2_format *f)
+{
+	int ret;
+	struct virtio_video_stream *stream = file2stream(file);
+
+	ret = virtio_video_s_fmt(file, fh, f);
+	if (ret)
+		return ret;
+
+	if (!V4L2_TYPE_IS_OUTPUT(f->type)) {
+		if (virtio_video_state(stream) == STREAM_STATE_IDLE)
+			virtio_video_state_update(stream, STREAM_STATE_INIT);
+	}
+
+	return 0;
+}
+
+static int virtio_video_enc_try_framerate(struct virtio_video_stream *stream,
+					  unsigned int fps)
+{
+	int rate_idx;
+	struct video_format_frame *frame = NULL;
+
+	if (stream->current_frame == NULL)
+		return -EINVAL;
+
+	frame = stream->current_frame;
+	for (rate_idx = 0; rate_idx < frame->frame.num_rates; rate_idx++) {
+		struct virtio_video_format_range *frame_rate =
+			&frame->frame_rates[rate_idx];
+
+		if (within_range(frame_rate->min, fps, frame_rate->max))
+			return 0;
+	}
+
+	return -EINVAL;
+}
+
+static void virtio_video_timeperframe_from_info(struct video_format_info *info,
+						struct v4l2_fract *timeperframe)
+{
+	timeperframe->numerator = 1;
+	timeperframe->denominator = info->frame_rate;
+}
+
+static int virtio_video_enc_g_parm(struct file *file, void *priv,
+				   struct v4l2_streamparm *a)
+{
+	struct virtio_video_stream *stream = file2stream(file);
+	struct virtio_video_device *vvd = to_virtio_vd(stream->video_dev);
+	struct v4l2_outputparm *out = &a->parm.output;
+	struct v4l2_fract *timeperframe = &out->timeperframe;
+
+	if (virtio_video_state(stream) == STREAM_STATE_ERROR)
+		return -EIO;
+
+	if (!V4L2_TYPE_IS_OUTPUT(a->type)) {
+		v4l2_err(&vvd->v4l2_dev,
+			 "getting FPS is only possible for the output queue\n");
+		return -EINVAL;
+	}
+
+	out->capability = V4L2_CAP_TIMEPERFRAME;
+	virtio_video_timeperframe_from_info(&stream->in_info, timeperframe);
+
+	return 0;
+}
+
+static int virtio_video_enc_s_parm(struct file *file, void *priv,
+				   struct v4l2_streamparm *a)
+{
+	int ret;
+	u64 frame_interval, frame_rate;
+	struct video_format_info info;
+	struct virtio_video_stream *stream = file2stream(file);
+	struct virtio_video_device *vvd = to_virtio_vd(stream->video_dev);
+	struct v4l2_outputparm *out = &a->parm.output;
+	struct v4l2_fract *timeperframe = &out->timeperframe;
+
+	if (virtio_video_state(stream) == STREAM_STATE_ERROR)
+		return -EIO;
+
+	if (V4L2_TYPE_IS_OUTPUT(a->type)) {
+		frame_interval = timeperframe->numerator * (u64)USEC_PER_SEC;
+		do_div(frame_interval, timeperframe->denominator);
+		if (!frame_interval)
+			return -EINVAL;
+
+		frame_rate = (u64)USEC_PER_SEC;
+		do_div(frame_rate, frame_interval);
+	} else {
+		v4l2_err(&vvd->v4l2_dev,
+			 "setting FPS is only possible for the output queue\n");
+		return -EINVAL;
+	}
+
+	ret = virtio_video_enc_try_framerate(stream, frame_rate);
+	if (ret)
+		return ret;
+
+	virtio_video_format_fill_default_info(&info, &stream->in_info);
+	info.frame_rate = frame_rate;
+
+	virtio_video_cmd_set_params(vvd, stream, &info,
+				    VIRTIO_VIDEO_QUEUE_TYPE_INPUT);
+	virtio_video_stream_get_params(vvd, stream);
+
+	out->capability = V4L2_CAP_TIMEPERFRAME;
+	virtio_video_timeperframe_from_info(&stream->in_info, timeperframe);
+
+	return 0;
+}
+
+static int virtio_video_enc_s_selection(struct file *file, void *fh,
+					struct v4l2_selection *sel)
+{
+	struct virtio_video_stream *stream = file2stream(file);
+	struct virtio_video_device *vvd = to_virtio_vd(stream->video_dev);
+	int ret;
+
+	if (!V4L2_TYPE_IS_OUTPUT(sel->type))
+		return -EINVAL;
+
+	switch (sel->target) {
+	case V4L2_SEL_TGT_CROP:
+		stream->in_info.crop.top = sel->r.top;
+		stream->in_info.crop.left = sel->r.left;
+		stream->in_info.crop.width = sel->r.width;
+		stream->in_info.crop.height = sel->r.height;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = virtio_video_cmd_set_params(vvd, stream,  &stream->in_info,
+					  VIRTIO_VIDEO_QUEUE_TYPE_INPUT);
+	if (ret)
+		return -EINVAL;
+
+	return virtio_video_cmd_get_params(vvd, stream,
+					   VIRTIO_VIDEO_QUEUE_TYPE_INPUT);
+}
+
+static const struct v4l2_ioctl_ops virtio_video_enc_ioctl_ops = {
+	.vidioc_querycap	= virtio_video_querycap,
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5, 3, 0))
+	.vidioc_enum_fmt_vid_cap        = virtio_video_enc_enum_fmt_vid_cap,
+	.vidioc_enum_fmt_vid_out        = virtio_video_enc_enum_fmt_vid_out,
+#else
+	.vidioc_enum_fmt_vid_cap_mplane = virtio_video_enc_enum_fmt_vid_cap,
+	.vidioc_enum_fmt_vid_out_mplane = virtio_video_enc_enum_fmt_vid_out,
+#endif
+	.vidioc_g_fmt_vid_cap_mplane	= virtio_video_g_fmt,
+	.vidioc_s_fmt_vid_cap_mplane	= virtio_video_enc_s_fmt,
+
+	.vidioc_g_fmt_vid_out_mplane	= virtio_video_g_fmt,
+	.vidioc_s_fmt_vid_out_mplane	= virtio_video_enc_s_fmt,
+
+	.vidioc_try_encoder_cmd	= virtio_video_try_encoder_cmd,
+	.vidioc_encoder_cmd	= virtio_video_encoder_cmd,
+	.vidioc_enum_frameintervals = virtio_video_enum_framemintervals,
+	.vidioc_enum_framesizes = virtio_video_enum_framesizes,
+
+	.vidioc_g_selection = virtio_video_g_selection,
+	.vidioc_s_selection = virtio_video_enc_s_selection,
+
+	.vidioc_reqbufs		= virtio_video_reqbufs,
+	.vidioc_querybuf	= v4l2_m2m_ioctl_querybuf,
+	.vidioc_qbuf		= virtio_video_qbuf,
+	.vidioc_dqbuf		= virtio_video_dqbuf,
+	.vidioc_prepare_buf	= v4l2_m2m_ioctl_prepare_buf,
+	.vidioc_create_bufs	= v4l2_m2m_ioctl_create_bufs,
+	.vidioc_expbuf		= v4l2_m2m_ioctl_expbuf,
+
+	.vidioc_streamon	= v4l2_m2m_ioctl_streamon,
+	.vidioc_streamoff	= v4l2_m2m_ioctl_streamoff,
+
+	.vidioc_s_parm		= virtio_video_enc_s_parm,
+	.vidioc_g_parm		= virtio_video_enc_g_parm,
+
+	.vidioc_subscribe_event = virtio_video_subscribe_event,
+	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
+};
+
+void *virtio_video_enc_get_fmt_list(struct virtio_video_device *vvd)
+{
+	return &vvd->output_fmt_list;
+}
+
+static struct virtio_video_device_ops virtio_video_enc_ops = {
+	.init_ctrls = virtio_video_enc_init_ctrls,
+	.init_queues = virtio_video_enc_init_queues,
+	.get_fmt_list = virtio_video_enc_get_fmt_list,
+};
+
+int virtio_video_enc_init(struct virtio_video_device *vvd)
+{
+	ssize_t num;
+	struct video_device *vd = &vvd->video_dev;
+
+	vd->ioctl_ops = &virtio_video_enc_ioctl_ops;
+	vvd->ops = &virtio_video_enc_ops;
+
+	num = strscpy(vd->name, "stateful-encoder", sizeof(vd->name));
+	if (num < 0)
+		return num;
+
+	return 0;
+}