Re: [PATCH 0/4] WIP: rockchip mpp for v4l2 video decoder

[Ezequiel Garcia]

Hey Ayaka!

On Thu, 2019-01-31 at 11:13 +0800, ayaka wrote:
> From: Randy 'ayaka' Li <ayaka@xxxxxxxxxxx>
> 
> Hello
>   Those patches are based on the previous vendor driver I post before,
> but it can apply without the previous one.
>   I really want to make it work before FOSDEM and I didn't. And upcoming
> the lunar new year holiday would last two week.
> 
>   I have verified the v4l2 part but I meet a problem with power or
> clock, it would be a complex problem, I would handle to solve it after I
> am back. But I just tell my design on this kind dirver.
> 

This the branch I'm about to submit:

http://git.infradead.org/users/ezequielg/linux/shortlog/refs/heads/vpu-mpeg-2-almost-ready-for-upstream

And it has no power issues. Perhaps you can take a look inside,
you might be just missing a few pm_ statements? Perhaps a devicetree thing?

> A few questions I think you may ask I would like to answer it here.
> 

I have another question: is this patchset meant to support for mpeg-2
decoding only? I can't find any other codec code.

Thanks,
Ezequiel

> 1. Why it is based on the previous vendor driver ?
> The vendor driver I post to mail list is a clean version which having a
> efficient work flow and those platform dependency controls having been
> merged into it.
> 
> For the stateless device, V4L2 is just another interface for userspace
> to translate it into registers.
> 
> 2. Why use a structure to store register infomation not marco ?
> I really don't want to define many marcos for a device having more than
> a hundred of registers. And there are many fields in a registers.
> 
> For the VDPU1/VDPU2 which would support more than 10 video codecs, these
> two devices would re-use many registers for many codecs, It would be
> hard to show the conflict relations between them in marco but more easy
> with C union and structure.
> 
> BTW, I would prefer to write a number of registers into the device
> though AHB bus not just generate one then write one, you can save some
> times here.
> 
> 
> Besides the two previous answers. I really have a big problem with v4l2
> design. Which would driver wait the work of the previous picture is
> done, leading a large gap time more idle of the device. 
> 
> I am ok the current face that v4l2 stateless driver is not stateless.
> But it would limit the ability of stateless decoder. It is more flexible
> to those videos having different resolution or orientation sequences.
> 
> But I don't like the method to reconstruct the bitstream in driver, it
> is a bad idea to limit what data the device want. Those problem is
> mainly talking in the HEVC slice thread. And it was ironic for the VPx
> serial codec, which mixed compressed data and umcompress header together
> and twisted. Even for the ITU H serial codec, it would become a problem
> in SVC or Google Android CTS test.
> 
> And thanks kwiboo, ezequielg and Paulk, I copy some v4l2 code from their
> code.
> 
> Randy Li (1):
>   staging: video: rockchip: add video codec
> 
> ayaka (3):
>   [WIP]: staging: video: rockchip: add v4l2 common
>   [WIP] staging: video: rockchip: vdpu2
>   [TEST]: rockchip: mpp: support qtable
> 
>  drivers/staging/Kconfig                       |    2 +
>  drivers/staging/Makefile                      |    1 +
>  drivers/staging/rockchip-mpp/Kconfig          |   54 +
>  drivers/staging/rockchip-mpp/Makefile         |    8 +
>  drivers/staging/rockchip-mpp/mpp_debug.h      |   87 ++
>  drivers/staging/rockchip-mpp/mpp_dev_common.c | 1365 +++++++++++++++++
>  drivers/staging/rockchip-mpp/mpp_dev_common.h |  215 +++
>  drivers/staging/rockchip-mpp/mpp_dev_rkvdec.c |  878 +++++++++++
>  drivers/staging/rockchip-mpp/mpp_dev_vdpu2.c  |  755 +++++++++
>  drivers/staging/rockchip-mpp/mpp_service.c    |  197 +++
>  drivers/staging/rockchip-mpp/mpp_service.h    |   38 +
>  drivers/staging/rockchip-mpp/rkvdec/hal.h     |   53 +
>  drivers/staging/rockchip-mpp/rkvdec/regs.h    |  395 +++++
>  drivers/staging/rockchip-mpp/vdpu2/hal.h      |   52 +
>  drivers/staging/rockchip-mpp/vdpu2/mpeg2.c    |  253 +++
>  drivers/staging/rockchip-mpp/vdpu2/regs.h     |  699 +++++++++
>  16 files changed, 5052 insertions(+)
>  create mode 100644 drivers/staging/rockchip-mpp/Kconfig
>  create mode 100644 drivers/staging/rockchip-mpp/Makefile
>  create mode 100644 drivers/staging/rockchip-mpp/mpp_debug.h
>  create mode 100644 drivers/staging/rockchip-mpp/mpp_dev_common.c
>  create mode 100644 drivers/staging/rockchip-mpp/mpp_dev_common.h
>  create mode 100644 drivers/staging/rockchip-mpp/mpp_dev_rkvdec.c
>  create mode 100644 drivers/staging/rockchip-mpp/mpp_dev_vdpu2.c
>  create mode 100644 drivers/staging/rockchip-mpp/mpp_service.c
>  create mode 100644 drivers/staging/rockchip-mpp/mpp_service.h
>  create mode 100644 drivers/staging/rockchip-mpp/rkvdec/hal.h
>  create mode 100644 drivers/staging/rockchip-mpp/rkvdec/regs.h
>  create mode 100644 drivers/staging/rockchip-mpp/vdpu2/hal.h
>  create mode 100644 drivers/staging/rockchip-mpp/vdpu2/mpeg2.c
>  create mode 100644 drivers/staging/rockchip-mpp/vdpu2/regs.h
>