Re: [PATCH 2/2] ARM: remove support for NOMMU ARMv4/v5

From: Robin Murphy <robin.murphy@arm.com>
To: Arnd Bergmann <arnd@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>
Cc: Russell King <linux@armlinux.org.uk>,
	Arnd Bergmann <arnd@arndb.de>, kernel test robot <lkp@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Marc Zyngier <maz@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Vladimir Murzin <vladimir.murzin@arm.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
	Anshuman Khandual <anshuman.khandual@arm.com>
Subject: Re: [PATCH 2/2] ARM: remove support for NOMMU ARMv4/v5
Date: Thu, 10 Mar 2022 14:21:00 +0000	[thread overview]
Message-ID: <39f8d67f-dd0b-e8de-e007-619eee86c98e@arm.com> (raw)
In-Reply-To: <CAK8P3a02a-+k=ChdT_Lg=xvHYZ4WTb-Efu7aQq-yBP1Gn37TgA@mail.gmail.com>

On 2022-03-10 09:23, Arnd Bergmann wrote:
> On Thu, Mar 10, 2022 at 2:22 AM Linus Walleij <linus.walleij@linaro.org> wrote:
>>
>> On Wed, Mar 9, 2022 at 5:17 PM Arnd Bergmann <arnd@kernel.org> wrote:
>>> Robin
>>>> In that case, it would probably make sense to garbage-collect all the
>>>> configs, setup code and other stuff relating to older MMU-less CPU cores
>>>> like ARM1156, ARM940, etc. at the same time.
>>>
>>> Right, good idea. These are only selected by CONFIG_ARCH_INTEGRATOR,
>>> but that in turn doesn't build for CONFIG_MMU=n because it depends on
>>> ARCH_MULTIPLATFORM. I'll send a patch for these.
>>
>> Just delete these, I do have these CPU tiles around but they are so obscure
>> and I never got around to even testing to boot them.
> 
> Right, of course you couldn't boot test them because it has been
> impossible to even select them in Kconfig for years. I've added
> a patch to completely remove the five v4/v5 NOMMU cores now,
> will send that later.
> 
> There are five more cores that are only referenced by mach-integrator
> that are supposed to work (922T, 1020, 1020E, 1022, 1026). Have you
> ever tested those, or should we consider removing them as well?
> 
> At some point, there was a proposal to add an arm10 based SoC
> to mainline, but that never happened and I'm fairly sure it won't
> come back now.

FWIW I have an Integrator/CM1026 that I'd love to play with purely for 
giggles, but it needs some serious archaeology to find and flash some 
firmware for it first.

I also have a couple of "real" ARM1026s in the form of Conexant 
Solos-based routers[1] which I've done a little hacking on, but don't 
see myself ever realistically having enough time or motivation to 
actually upstream anything. And at this point I don't see OpenWRT having 
any more interest in boards with only 15MB of RAM (yes, they really do 
boot with "mem=15M" to reserve 1MB for the modem...)

Cheers,
Robin.

[1] https://openwrt.org/toh/linksys/wag54g2