Re: remove arch/sh

Geert Uytterhoeven
2023-01-17T22:01:28Z

Hi Rob,

On Tue, Jan 17, 2023 at 8:01 PM Rob Landley <rob@landley.net> wrote:
> On 1/16/23 01:13, Christoph Hellwig wrote:
> > On Fri, Jan 13, 2023 at 09:09:52AM +0100, John Paul Adrian Glaubitz wrote:
> >> I'm still maintaining and using this port in Debian.
> >>
> >> It's a bit disappointing that people keep hammering on it. It works fine for me.
> >
> > What platforms do you (or your users) use it on?
>
> 3 j-core boards, two sh4 boards (the sh7760 one I patched the kernel of), and an
> sh4 emulator.
>
> I have multiple j-core systems (sh2 compatible with extensions, nommu, 3
> different kinds of boards running it here). There's an existing mmu version of
> j-core that's sh3 flavored but they want to redo it so it hasn't been publicly
> released yet, I have yet to get that to run Linux because the mmu code would
> need adapting, but the most recent customer projects were on the existing nommu
> SOC, as was last year's ASIC work via sky130.

J4 still vaporware?

> My physical sh4 boards are a Johnson Controls N40 (sh7760 chipset) and the
> little blue one is... sh4a I think? (It can run the same userspace, I haven't
> replaced that board's kernel since I got it, I think it's the type Glaubitz is
> using? It's mostly in case he had an issue I couldn't reproduce on different
> hardware, or if I spill something on my N40.)
>
> I also have a physical sh2 board on the shelf which I haven't touched in years
> (used to comparison test during j2 development, and then the j2 boards replaced it).
>
> I'm lazy and mostly test each new sh4 build under qemu -M r2d because it's
> really convenient: neither of my physical boards boot from SD card so replacing
> the kernel requires reflashing soldered in flash. (They'll net mount userspace
> but I haven't gotten either bootloader to net-boot a kernel.)

On my landisk (with boots from CompactFLASH), I boot the original 2.6.22
kernel, and use kexec to boot-test each and every renesas-drivers
release. Note that this requires both the original 2.6.22 kernel
and matching kexec-tools. Apparently both upstreamed kernel and
kexec-tools support for SH are different, and incompatible with each
other, so you cannot kexec from a contemporary kernel.
I tried working my way up from 2.6.22, but gave up around 2.6.29.
Probably I should do this with r2d and qemu instead ;-)

Both r2d and landisk are SH7751.

Probably SH7722/'23'24 (e.g. Migo-R and Ecovec boards) are also
worth keeping. Most on-SoC blocks have drivers with DT support,
as they are shared with ARM. So the hardest part is clock and
interrupt-controller support.
Unfortunately I no longer have access to the (remote) Migo-R.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds