[Buildroot] [PATCH 3/3] boot: riscv: Remove riscv-pk

[Alistair Francis]

On Mon, Mar 18, 2019 at 3:45 AM Mark Corbin <mark.corbin at embecosm.com> wrote:
>
> Hello
>
> On 16/03/2019 07:43, Thomas Petazzoni wrote:
> > Hello,
> >
> > On Fri, 15 Mar 2019 23:06:39 +0000
> > Alistair Francis <Alistair.Francis at wdc.com> wrote:
> >
> >> Now that OpenSBI is supported remove BBL (riscv-pk).
> >>
> >> Signed-off-by: Alistair Francis <alistair.francis at wdc.com>
> > This commit is not enough: you do not update the
> > qemu_riscv64_virt_defconfig and qemu_riscv32_virt_defconfig, which use
> > riscv-pk. They should be converted to use opensbi instead, and of
> > course be runtime tested under Qemu.
> >
> > And of course, it'd be nice if Mark Corbin, who added riscv-pk, could
> > give his opinion about the replacement of riscv-pk by opensbi.
>
> I don't think that removing support for riscv-pk at this stage is
> desirable. I imagine that the majority (if not all) RISC-V systems have
> been using riscv-pk (BBL) up until this point, including the HiFive
> Unleashed board, so I expect that there are a lot of systems and people
> with time invested in using it. That said, I always imagined a migration
> path from riscv-pk to an alternative such as U-Boot (or OpenSBI or
> whatever).

I agree that up until OpenSBI almost all boards would have been using
BBL. The problem with BBL is that people were never investing time
into it. There was never a formal release and the code base is
difficult to maintain. I think that the sooner we can replace it the
better. Yocto/OpenEmbedded has fully swapped and Fedora is looking at
swapping as well.

OpenSBI allows us to not compile the kernel into the boot loader when
booting with QEMU. It also allows us to boot directly into u-boot on
QEMU and on hardware (with u-boot 2019.04). I think leaving it in
confuses people who might continue to use it as that is what they have
seen before, even though it is a bad choice.

>
> As the first release of OpenSBI was only at the end of January 2019, I
> would strongly suggest that we keep riscv-pk for a period of time
> (possibly commenting the intention to eventually deprecate it in favour
> of OpenSBI). This will give OpenSBI time to mature and users of riscv-pk
> a period to evaluate it and consider migrating.
>
> I do think that it would be a good start to test the existing QEMU virt
> configurations with OpenSBI and then update them as necessary.

Yep, I'll update the configurations in v2 as well as the
documentation. OpenSBI is well tested on QEMU in general.

Alistair

>
> Regards
>
> Mark
>
> >
> > Thanks!
> >
> > Thomas
>
> --
> Mark Corbin
> Embecosm Ltd.
> https://www.embecosm.com