Debian rootfs?

[Drew Fustini]

The existing busybox from linux-on-litex-vexriscv feels limiting but I'm not sure about the next steps are to make something with more functionality

There was discussion at FOSDEM about the potential of using Debian for rootfs.

I wanted to check with the list to see if anyone is working on this or interested in working on this?

Thanks,

Drew

[Gabriel L. Somlo]

Hi Drew,

I'm trying to get Fedora or Debian riscv64 booting on Rocket+Litex
(http://www.contrib.andrew.cmu.edu/~somlo/BTCP). The goal is a
self-hosting computer (i.e., Fedora's riscv64 port actually has
yosys/trellis/nextpnr packages) that can be used to develop any
of its own components with absolutely zero reliance on anything
but FOSS ingredients.

The current limitation is that LiteETH isn't solid enough (or maybe
at 60MHz and FPU-emulation-in-BBL the whole system isn't fast enough)
to really be usable via NFS-root, so I'm trying to iron out the kinks
in LiteSDCard, and boot from a pre-generated root file system.

At that point we should be able to (S L O W L Y) rebuild our own
underlying bitstream... :)

Let me know what you think.

Cheers,
--Gabriel

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[Tim 'mithro' Ansell]

It should be pretty easy for someone to use the buildroot patches to compile a better rootfs?

To view this discussion on the web, visit https://groups.google.com/d/msgid/linux-litex/20200203131530.GA9489%40errol.ini.cmu.edu.

[Gabriel L. Somlo]

On Mon, Feb 03, 2020 at 02:44:37PM +0100, Tim 'mithro' Ansell wrote:
> It should be pretty easy for someone to use the buildroot patches to compile a
> better rootfs?

The other problem I forgot to mention is the rather constrained (for
running a "real" distro) RAM available on most dev boards. It's 128MB
on e.g. the ecp5 versa. The Trellisboard is the current winner at 1GB,
and that might still be a bit tight w.r.t. compiling a LiteX+Rocket
bitstream (yosys' resident RAM on x86 for that was 1.3GB last time I
measured it).

So a filesystem on actual media (as opposed to RAM) is a pretty hard
requirement for my use case...

> CAHLUNMyqASV0P%2BBNqWgB_LGiZAGZtKQdzwxE4g-E2R%2BrzTixrQ%40mail.gmail.com.

[Drew Fustini]

On Mon, Feb 3, 2020 at 3:03 PM Gabriel L. Somlo <gso...@gmail.com> wrote:
> So a filesystem on actual media (as opposed to RAM) is a pretty hard
> requirement for my use case...

Do you know what a "small" installation of Fedora or Debian would require?

I guess it would be too much to fit into a SPI flash, so I can see why
you are looking at SD card. I should see if I can add SD cared via
PMOD to the hadbadge [1] as it only has 16MB flash.

Thanks,
Drew

[1] https://github.com/litex-hub/litex-boards/pull/31

[Gabriel L. Somlo]

On Wed, Feb 05, 2020 at 11:52:35AM +0100, Drew Fustini wrote:
> On Mon, Feb 3, 2020 at 3:03 PM Gabriel L. Somlo <gso...@gmail.com> wrote:
> > So a filesystem on actual media (as opposed to RAM) is a pretty hard
> > requirement for my use case...
>
> Do you know what a "small" installation of Fedora or Debian would require?

A small dedicated headless Fedora (x86_64) server I built came
in at 2.7G. Chances are one *could* further slim that down, but
the work involved in doing so might be a bigger effort than sorting
out LiteSDCard :)

> I guess it would be too much to fit into a SPI flash, so I can see why
> you are looking at SD card. I should see if I can add SD cared via
> PMOD to the hadbadge [1] as it only has 16MB flash.
>
> Thanks,
> Drew
>
> [1] https://github.com/litex-hub/litex-boards/pull/31
>

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