Re: [PATCH v3 2/2] mtd: rawnand: ingenic: Limit MTD_NAND_JZ4780 to architecture only

From: Krzysztof Kozlowski <krzk@kernel.org>
To: Paul Cercueil <paul@crapouillou.net>
Cc: Vignesh Raghavendra <vigneshr@ti.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Richard Weinberger <richard@nod.at>,
	linux-kernel@vger.kernel.org,
	Harvey Hunt <harveyhuntnexus@gmail.com>,
	linux-mtd <linux-mtd@lists.infradead.org>,
	Miquel Raynal <miquel.raynal@bootlin.com>
Subject: Re: [PATCH v3 2/2] mtd: rawnand: ingenic: Limit MTD_NAND_JZ4780 to architecture only
Date: Sun, 26 Jul 2020 18:15:45 +0200	[thread overview]
Message-ID: <20200726161545.GA6058@kozik-lap> (raw)
In-Reply-To: <RO33EQ.546WD84D5N7K2@crapouillou.net>

On Sun, Jul 26, 2020 at 06:12:27PM +0200, Paul Cercueil wrote:
> 
> 
> Le dim. 26 juil. 2020 à 18:06, Krzysztof Kozlowski <krzk@kernel.org> a écrit
> :
> > On Sat, Jul 25, 2020 at 08:30:56PM +0200, Arnd Bergmann wrote:
> > >  On Sat, Jul 25, 2020 at 2:17 PM Paul Cercueil
> > > <paul@crapouillou.net> wrote:
> > >  > Le ven. 24 juil. 2020 à 17:54, Krzysztof Kozlowski
> > > <krzk@kernel.org> a
> > >  > écrit :
> > >  > > On Fri, Jul 24, 2020 at 05:50:06PM +0200, Paul Cercueil wrote:
> > >  > >>  Le ven. 24 juil. 2020 à 17:33, Krzysztof Kozlowski
> > >  > >> <krzk@kernel.org> a écrit:
> > >  > >>  > On Fri, 24 Jul 2020 at 17:19, Paul Cercueil
> > > <paul@crapouillou.net>
> > >  > >>  > wrote:
> > >  > >>
> > >  > >>  On MIPS, the SoC selection is a Kconfig "choice", so you can
> > > only
> > >  > >> support
> > >  > >>  one SoC family, unfortunately.
> > >  > >
> > >  > > Let's say someone selected then some other architecture
> > >  > > (MIPS_ALCHEMY).
> > >  > > They could select this MTD driver.
> > >  > >
> > >  > > Does it mean they would be able to run it on Ingenic hardware?
> > >  >
> > >  > In *theory* yes, as long as the Kconfig options that MACH_INGENIC
> > >  > selects are enabled, the kernel should boot and work on Ingenic
> > > SoCs.
> > > 
> > >  Right now, this won't work yet, because there are platform specific
> > >  functions that are implemented by each of the platforms in
> > > arch/mips,
> > >  e.g. arch/mips/generic/init.c and arch/mips/jz4740/setup.c.
> > 
> > I would say even more - no DTS would be provided for such configuration.
> > All Ingenic DTSes are included only with MACH_INGENIC.  You cannot build
> > a kernel working on Ingenic without MACH_INGENIC. Even in theory.
> 
> But the devicetree doesn't have to be built-in.
>

OK, that's true. Anyway, I don't have strong opinion on any of this. I
just followed Arnd's hint.

For the memory driver (and MTD NAND as well) which one you prefer:
1. https://lore.kernel.org/lkml/20200724074038.5597-6-krzk@kernel.org/
2. depends on MACH_INGENIC || MIPS_GENERIC || COMPILE_TEST

?

Best regards,
Krzysztof

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