Add to SkiffOS

[paralin]

SkiffOS is a configuration package management tool for Buildroot which makes it easy to retarget a system across a wide variety of underlying hardware.

Considering that litex is already using buildroot, it would be easy to format the configs, patches, etc, into a Skiff package, and then use that to load other distros (Gentoo, Ubuntu, NixOS, ...) easily into the system while inheriting compiler information.

https://github.com/skiffos/skiffos

[paralin]

The litex/vexriscv package has been implemented based on this repo:

https://github.com/skiffos/SkiffOS/pull/135

https://github.com/skiffos/SkiffOS/tree/litex/configs/litex/vexriscv

I don't have any hardware to test at the moment.

[enjoy-digital]

Thanks @paralin, this seems really interesting and we'll explore this. From what I understand you've already been able to run the image with sim.py from Linux-on-LiteX-VexRiscv? If so, this should also run on hardware and I would be happy to do tests on hardware for you.

[paralin]

Apparently a lot of additional Risc-v support just landed in Go and Docker as well. I've added a squashfs based boot mechanism that doesn't use an initramfs (to save memory) and most of the kernel options can probably be disabled. I know these chips have very low resources so as minimal of an image as possible is necessary.

The current output from Skiff should work with the sim script, there's a TODO to add a "make" command to run it automatically (by downloading this repo & running it).

Will post again here once I've tested it with sim.py

[paralin]

Allwinner Nezha support is in place in SkiffOS, which is a risc-v board commonly available with D1 by Allwinner.

Planning to revisit adding the litex config soon.

(This recently included adding support for riscv to Go in Buildroot).

[enjoy-digital]

Great, thanks for the update @paralin! Really interesting. Compiling custom packages with buildroot is becoming a bit complicated when testing Linux-on-LiteX-VexRiscv and SkiffOS could be really interesting. @Dolu1990 (who might also be interested by this) also implemented a new NaxRiscv CPU that is 64-bit capable and could simplify your work since probably closer to the D1. We are also able to use Rocket as 64-bit CPU.

For NaxRiscv, add to your target/sim command: --cpu-type=naxriscv --xlen=64 For Rocket: --cpu-type=rocket

[enjoy-digital]

Happy to help you getting started or do some tests for you in simulation or on hardware if needed.

[paralin]

@enjoy-digital I'm looking to finish this work soon, circling back. We support the D1 in SkiffOS already today.

Could add a command to run the simulator.