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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Tue, 17 Jan 2023 21:26:27 +0100
Message-ID: <CAMuHMdUJm5QvzH8hvqwvn9O6qSbzNOapabjw5nh9DJd0F55Zdg@mail.gmail.com>
Subject: Re: remove arch/sh
To:     Rob Landley <rob@landley.net>
Cc:     Christoph Hellwig <hch@lst.de>,
        John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        linux-kernel@vger.kernel.org, linux-watchdog@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arch@vger.kernel.org,
        dmaengine@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-renesas-soc@vger.kernel.org, linux-i2c@vger.kernel.org,
        linux-input@vger.kernel.org, linux-media@vger.kernel.org,
        linux-mmc@vger.kernel.org, linux-mtd@lists.infradead.org,
        netdev@vger.kernel.org, linux-gpio@vger.kernel.org,
        linux-rtc@vger.kernel.org, linux-spi@vger.kernel.org,
        linux-serial@vger.kernel.org, linux-usb@vger.kernel.org,
        linux-fbdev@vger.kernel.org, alsa-devel@alsa-project.org,
        linux-sh@vger.kernel.org
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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