Re: RPI 4/5 u-boot new port, is there any interest?

On Wed, Jun 4, 2025, 9:11 AM Mark Millard <marklmi@yahoo.com> wrote:

> On Jun 4, 2025, at 08:54, Warner Losh <imp@bsdimp.com> wrote:
>
> > On Wed, Jun 4, 2025 at 8:50 AM Mark Millard <marklmi@yahoo.com> wrote:
> >>
> >> On Jun 4, 2025, at 05:33, Klaus Küchemann <maciphone2@googlemail.com>
> wrote:
> >>
> >>> a while ago, I spoke in more detail with bz@ about u-boot for the
> Pi5. There are ways to create a new port...
> >>> Now I had a longer conversation with Hugo Kirnbichler on Discord. Hugo
> managed to patch u-boot for the RPI CM4 to make it NVMe bootable (compiled
> under FreeBSD).
> >>> Details would go beyond the scope here for the first.
> >>>
> >>> What I would like to know:
> >>> Is FreeBSD still interested in supporting the RPI4/5?
> >>> Goodbye Pi in FreeBSD or Hello Pi , especially now ? :-)
> >>>
> >>> Then Hugo and I might be willing to create a new port.
> >>> There's no other way to proceed...
> >>
> >> I wonder if FreeBSD's kboot (LinuxBoot context) might be a
> >> way to avoid both EDK2 and a FreeBSD specific U-Boot and
> >> better track booting what Linux can boot (once FreeBSD has
> >> kernel support for the context).
>
> I just discovered from https://book.linuxboot.org/ that there is:
>
>     • k-boot developed by BayLibre in 2023 using BusyBox
>     • kboot developed by Werner Almesberger in 2005 (no longer maintained)
>
> Just shows how little context I have.
>

Our kboot just shares a name with Werner's work on a PS-3 boot loader...

Warner

> In aarch64, UEFI is still around in LinuxBoot environments. Granted,
> > it's just the UEFI runtime that is needed. The linux kernel handles the
> > hand off, and then "provides" sufficient metadata to the exec'd kernel
> > to reconnect to this. So there needs to be some kind of thing that
> > provides this. I don't know what the state of play is with the uboot
> > vs edk2 ports to the rpi5. But once you have the minimal Linux kernel
> > booted, FreeBSD could further boot from there. But if you can boot
> > linux.efi, chances are quite good you could boot FreeBSD's loader.efi
> > so I struggle to see how this would help, though it might.
>
> Thanks for the notes.
>
> > Warner
> >
> >> I've no clue if it might well apply to a RPi* context. But
> >> other aarch64 boards?
> >>
> >>> the u-boot mailing lists are aware of the problems, but nothing is
> happening because they don't need it for Linux. All the patches we know of
> are GPL’d from 3rd party companies or OS-projects afaik.
> >>>
> >>> Because it’s not really fun :-) , I don't want to continue this work
> if there is no official interest from FreeBSD.
> >>> If you are interested, we would be happy to discuss the details here.
>
>
> ===
> Mark Millard
> marklmi at yahoo.com
>
>
>