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

From: Paul Cercueil <paul@crapouillou.net>
To: Krzysztof Kozlowski <krzk@kernel.org>
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@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: Sat, 25 Jul 2020 14:17:44 +0200	[thread overview]
Message-ID: <K5Y0EQ.WYAK00ADM46F3@crapouillou.net> (raw)
In-Reply-To: <20200724155436.GA7460@kozik-lap>

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:
>>  > >
>>  > >  Hi Krzysztof,
>>  > >
>>  > >
>>  > >  Le ven. 24 juil. 2020 à 16:54, Krzysztof Kozlowski
>>  > > <krzk@kernel.org> a
>>  > >  écrit :
>>  > >  > Enabling the MTD_NAND_JZ4780 driver makes sense only for 
>> specific
>>  > >  > hardware - the Ingenic SoC architecture.  Set it's 
>> dependency to
>>  > >  > MACH_INGENIC so it will not appear on unrelated architectures
>>  > > (easier
>>  > >  > job for downstream/distro kernel engineers).
>>  > >
>>  > >  Disagreed. It was done this way so that distro kernels can 
>> support
>>  > >  multiple SoCs.
>>  >
>>  > They will still be able to support multiple SoCs. Nothing changed
>>  > here. The same we do for all ARM drivers (SoCs are 
>> multiplatform)...
>>  > Unless you want to say that it is possible to support Ingenic SoC
>>  > without MACH_INGENIC?
>> 
>>  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.

-Paul

>>  I'm the one to blame for using "depends on
>>  MIPS || COMPILE_TEST" on ingenic drivers, maybe it should depend on
>>  MACH_INGENIC indeed, but then it should be made possible to support 
>> more
>>  than one SoC family.
>> 
>>  That's something that should be pointed out to the MIPS mailing 
>> list, I
>>  believe.
> 
> Somehow JZ4780 entries in Maintainers do not mention MIPS list...
> 
>> 
>>  Btw: Does that mean you are the new maintainer for drivers/memory/?
> 
> Yes, that's the coming change.
> 
> https://lore.kernel.org/lkml/20200724140345.GB13472@kozik-lap/T/#m91ca20920a7ec5f228a595f1816c15b6c85b6a09
> 
> Best regards,
> Krzysztof
> 

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