Re: remove arch/sh

[Guenter Roeck]

On 1/17/23 12:26, Geert Uytterhoeven wrote:
> Hi Rob,
>
> On Tue, Jan 17, 2023 at 8:01 PM Rob Landley <rob@xxxxxxxxxxx> 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.

Since there are people around with real hardware .... is sh in big endian mode
(sheb) real ? Its qemu support is quite limited; most PCI devices don't work
due to endianness issues. It would be interesting to know if this works better
with real hardware.

Thanks,
Guenter