VPU : Find a way to generate automatic patches, for importing the V4L2 and VPU patches, form the rockchip 5.x tree, to the Linus mainline tree.

[Miouyouyou]

Currently, the VPU patches posted on the Rockchip Mailing List are based on the Rockchip 5.x tree from Heiko Stübner (I guess ? It's not really obvious).

So, almost everytime I try a patch series implementing some VPU stuff, into the mainline kernel, it fails to compile due to some dependencies on some obscure V4L2 request functions, that are not available on the Linus tree since the V4L2 Request API is a Work In Progress thing.

In order to be apply thoses patches, I'll need to :

• [x] Determine clearly which kernel tree is used as a basis
• [ ] Determine the files that clearly necessary. Currently that involves : The clocks, V4L2, Videobuf2, DMA, IOMMU, VPU, DTS and UAPI headers.
• [ ] Create a dumb script that : Clones the Linus tree, clones the Rockchip tree, copy the useful files and generates a patch from it.
• [ ] Use this as a basis to test the various VPU patches provided
• [x] Find a way to test these patches (Softwares required, ...)
• [ ] Automate those tests (LAVA maybe ?)

[Miouyouyou]

Okay, so the kernel used is certainly not mmind's one... And Rockchip doesn't seem to provide 5.x kernels... So people are using magic kernels from wonderlands.

Meanwhile, I found a few V4L2 patches that provide the symbols and definitions for H264 and HEVC handling within V4L2. Since they essentially target Allwinner SoC VPU, maybe they're using some kernels that include the VPU changes for the Allwinner SoC...

https://lkml.org/lkml/2019/2/20/502 https://lkml.org/lkml/2019/2/14/234

[Miouyouyou]

Also, the latest MPP patches from Randy Li are not useable as-is, since they don't include the VPU Decoder v1 (RK3288) code... So I guess that I'll use Ezequiel patches then.

[Miouyouyou]

Ok, I guess that they're using this branch : https://github.com/bootlin/linux-cedrus/commit/6e3a9b0538664ad993a5afedee0342901a37d782

I'll start using this branch as reference, and see how it goes.

[Miouyouyou]

Alright, a few automated scripts have been pushed here : https://github.com/Miouyouyou/RockMyy/tree/VPU-V4L2-5.x

[Miouyouyou]

Kwiboo's MPEG-2 decoding driver for the VPU has been added on the mainline tree.

[Miouyouyou]

The whole Hantro VPU driver is now 'staged' into the kernel

Some correct support from the FFMPEG side is still required, but that's another story. Closing this one for now.