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

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    • kboot developed by Werner Almesberger in 2005 (no longer maintained)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.

> 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