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Date:   Fri, 05 Jul 2019 22:51:55 +0900
Message-ID: <87a7ds4mis.wl-ysato@users.sourceforge.jp>
From:   Yoshinori Sato <ysato@users.sourceforge.jp>
To:     Rich Felker <dalias@libc.org>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
        Adam Borowski <kilobyte@angband.pl>,
        Christoph Hellwig <hch@lst.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Linux-sh list <linux-sh@vger.kernel.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] remove arch/sh?
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On Thu, 27 Jun 2019 00:38:21 +0900,
Rich Felker wrote:
> 
> On Wed, Jun 26, 2019 at 08:25:20PM +0900, Yoshinori Sato wrote:
> > On Wed, 26 Jun 2019 00:48:09 +0900,
> > Arnd Bergmann wrote:
> > > 
> > > On Tue, Jun 25, 2019 at 4:28 PM Rich Felker <dalias@libc.org> wrote:
> > > > On Tue, Jun 25, 2019 at 02:50:01PM +0200, Arnd Bergmann wrote:
> > > > > don't build, or are incomplete and not worked on for a long
> > > > > time, compared to the bits that are known to work and that someone
> > > > > is still using or at least playing with.
> > > > > I guess a lot of the SoCs that have no board support other than
> > > > > the Hitachi/Renesas reference platform can go away too, as any products
> > > > > based on those boards have long stopped updating their kernels.
> > > >
> > > > My intent here was always, after getting device tree theoretically
> > > > working for some reasonable subset of socs/boards, drop the rest and
> > > > add them back as dts files (possibly plus some small drivers) only if
> > > > there's demand/complaint about regression.
> > > 
> > > Do you still think that this is a likely scenario for the future though?
> > > 
> > > If nobody's actively working on the DT support for the old chips and
> > > this is unlikely to change soon, removing the known-broken bits earlier
> > > should at least make it easier to keep maintaining the working bits
> > > afterwards.
> > > 
> > > FWIW, I went through the SH2, SH2A and SH3 based boards that
> > > are supported in the kernel and found almost all of them to
> > > be just reference platforms, with no actual product ever merged.
> > > IIRC the idea back then was that users would supply their
> > > own board files as an add-on patch, but I would consider all the
> > > ones that did to be obsolete now.
> > > 
> > > HP Jornada 6xx is the main machine that was once supported, but
> > > given that according to the defconfig file it only comes with 4MB
> > > of RAM, it is unlikely to still boot any 5.x kernel, let alone user
> > > space (wikipedia claims there were models with 16MB of RAM,
> > > but that is still not a lot these days).
> > > 
> > > "Magicpanel" was another product that is supported in theory, but
> > > the google search showed the 2007 patch for the required
> > > flash storage driver that was never merged.
> > > 
> > > Maybe everything but J2 and SH4(a) can just get retired?
> > > 
> > >      Arnd
> > 
> > I also have some boards, so it's possible to rewrite more.
> > I can not rewrite the target I do not have, so I think that
> > there is nothing but to retire.
> 
> To clarify, are you agreeing with Arnd's suggestion to retire/remove
> everything but jcore and sh4[a]?
> 
> Rich

I have SH2/2A/3 target board.
So can mantain CPU support.
But with board support it will be difficult.
I would like to make the transition to a common framework.
I also have to fix the parts that depend on each board for migration,
so I would like to limit the target for maintenance to only those
that can be used now.

-- 
Yosinori Sato