meta-riscv - A Yocto/OpenEmbedded Layer for RISC-V

[Khem Raj]

Hi All,

I am happy to let you all know that we have RISC-V Yocto layer working
with latest upstream master of Yocto project, its currently hosted here

https://github.com/riscv/meta-riscv

We are able to build images for qemuriscv64 out of box.
README.md lists the instructions for setting up workspace, doing builds
and running them in qemu. Intention is to use upstream components as
much as we can. Currently, a handful components are being built from
forks, most of it is using upstream provided components.

SiFive freedom-u500 board support was added to OE/Yocto during ELC
hackathon and it booted successfully, currently, there is an active pull
request for adding that support (on my fork). Hopefully this will be in
soon.

by selecting
MACHINE="riscv32" bitbake meta-toolchain
one can generate baremetal SDK installers, which can be used to build
baremetal stuff e.g. zephyr. It has not been documented yet.

Yocto also has autotests which can be run automatically in qemu after
image builds, It however does not work yet, I think there is some setup
issue there where test framework opens up another serial console to
monitor the console logs, and currently that is failing to recognize the
output so system does not notice that it has booted successfully and
therefor curtails the testing. This needs fixing, but I am sure with
next qemu release we will be able to use Qemu from yocto project so this
problem should go away, since there are patches for qemu to support
yocto testing which we haven't applied to risc-v qemu.

I have also tooled in travis autobuilder to trigger builds on pulls but
it takes a lot of time to build, and travis timeouts the build after
50mins :( (there is a limit for free loaders), so I guess we have to
hook in a different autobuilder with some more muscle then a single core VM.


Feel free to checkout and give it a try. If you run into issues I will
be glad to help.

Thanks to all contributors and happy hacking.

-Khem