Hello, Hans!
This is the version of the protocol with minor comments addressed
(that you had on v4). Hope this now looks OK.
Thank you,
Oleksandr
On 3/12/19 10:19 AM, Oleksandr Andrushchenko wrote:
From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
Hello!
At the moment Xen [1] already supports some virtual multimedia
features [2] such as virtual display, sound. It supports keyboards,
pointers and multi-touch devices all allowing Xen to be used in
automotive appliances, In-Vehicle Infotainment (IVI) systems
and many more.
Frontend implementation is available at [3] and the corresponding
backend at [4]. These are work in progress, but frontend already
passes v4l2-compliance test for V4L2 drivers. libxl preliminary
changes are available at [5].
This work adds a new Xen para-virtualized protocol for a virtual
camera device which extends multimedia capabilities of Xen even
farther: video conferencing, IVI, high definition maps etc.
The initial goal is to support most needed functionality with the
final idea to make it possible to extend the protocol if need be:
1. Provide means for base virtual device configuration:
- pixel formats
- resolutions
- frame rates
2. Support basic camera controls:
- contrast
- brightness
- hue
- saturation
3. Support streaming control
I would like to thank Hans Verkuil <hverkuil@xxxxxxxxx> for valuable
comments and help.
Thank you,
Oleksandr Andrushchenko
Changes since v4:
=================
1. Removed unused XENCAMERA_EVT_CFG_FLG_RESOL flag
2. Re-worded a bit description for num_buffers
Changes since v3:
=================
1. Add trimming example for short FOURCC labels, e.g. Y16 and Y16-BE
2. Remove from XENCAMERA_OP_CONFIG_XXX requests colorspace, xfer_func,
ycbcr_enc, quantization and move those into the corresponding response
3. Extend description of XENCAMERA_OP_BUF_REQUEST.num_bufs: limit to
maximum buffers and num_bufs == 0 case
4. Extend decription of XENCAMERA_OP_BUF_CREATE.index and specify its
range
5. Make XENCAMERA_EVT_FRAME_AVAIL.seq_num 32-bit instead of 64-bit
Changes since v2:
=================
1. Add "max-buffers" frontend configuration entry, e.g.
the maximum number of camera buffers a frontend may use.
2. Add big-endian pixel-format support:
- "formats" configuration string length changed from 4 to 7
octets, so we can also manage BE pixel-formats
- add corresponding comments to FOURCC mappings description
3. New commands added to the protocol and documented:
- XENCAMERA_OP_CONFIG_VALIDATE
- XENCAMERA_OP_FRAME_RATE_SET
- XENCAMERA_OP_BUF_GET_LAYOUT
4.-Add defaults for colorspace, xfer, ycbcr_enc and quantization
5. Remove XENCAMERA_EVT_CONFIG_CHANGE event
6. Move plane offsets to XENCAMERA_OP_BUF_REQUEST as offsets
required for the frontend might not be known at the configuration time
7. Clean up and address comments to v2 of the protocol
Changes since v1:
=================
1. Added XenStore entries:
- frame-rates
2. Do not require the FOURCC code in XenStore to be upper case only
3. Added/changed command set:
- configuration get/set
- buffer queue/dequeue
- control get
4. Added control flags, e.g. read-only etc.
5. Added colorspace configuration support, relevant constants
6. Added events:
- configuration change
- control change
7. Changed control values to 64-bit
8. Added sequence number to frame avail event
9. Coding style cleanup
[1] https://www.xenproject.org/
[2] https://xenbits.xen.org/gitweb/?p=xen.git;a=tree;f=xen/include/public/io
[3] https://github.com/andr2000/linux/tree/camera_front_v1/drivers/media/xen
[4] https://github.com/andr2000/camera_be
[5] https://github.com/andr2000/xen/tree/vcamera
Oleksandr Andrushchenko (1):
cameraif: add ABI for para-virtual camera
xen/include/public/io/cameraif.h | 1370 ++++++++++++++++++++++++++++++
1 file changed, 1370 insertions(+)
create mode 100644 xen/include/public/io/cameraif.h
