From:   "Alim Akhtar" <alim.akhtar@samsung.com>
To:     "'Arnd Bergmann'" <arnd@arndb.de>,
        "'Krzysztof Kozlowski'" <krzysztof.kozlowski@canonical.com>
Cc:     "'Linux ARM'" <linux-arm-kernel@lists.infradead.org>,
        "'Linux Kernel Mailing List'" <linux-kernel@vger.kernel.org>,
        "'SoC Team'" <soc@kernel.org>,
        "'linux-clk'" <linux-clk@vger.kernel.org>,
        "'DTML'" <devicetree@vger.kernel.org>,
        "'Olof Johansson'" <olof@lixom.net>,
        "'Linus Walleij'" <linus.walleij@linaro.org>,
        "'Catalin Marinas'" <catalin.marinas@arm.com>,
        "'Rob Herring'" <robh+dt@kernel.org>,
        "'Sylwester Nawrocki'" <s.nawrocki@samsung.com>,
        "'moderated list:ARM/SAMSUNG EXYNOS ARM ARCHITECTURES'" 
        <linux-samsung-soc@vger.kernel.org>,
        "'Pankaj Dubey'" <pankaj.dubey@samsung.com>, <linux-fsd@tesla.com>,
        "'Arjun K V'" <arjun.kv@samsung.com>,
        "'Aswani Reddy'" <aswani.reddy@samsung.com>,
        "'Ajay Kumar'" <ajaykumar.rs@samsung.com>,
        "'Sriranjani P'" <sriranjani.p@samsung.com>,
        "'Chandrasekar R'" <rcsekar@samsung.com>,
        "'Shashank Prashar'" <s.prashar@samsung.com>
In-Reply-To: <CAK8P3a0etf+AybUe5O9uRLAbo4J145t0-ThkEccNtKzue+0-qA@mail.gmail.com>
Subject: RE: [PATCH 14/23] arm64: dts: fsd: Add initial device tree support
Date:   Fri, 14 Jan 2022 13:43:20 +0530
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Hi Arnd and Krzysztof

>-----Original Message-----
>From: Arnd Bergmann =5Bmailto:arnd=40arndb.de=5D
>Sent: Thursday, January 13, 2022 7:54 PM
>To: Krzysztof Kozlowski <krzysztof.kozlowski=40canonical.com>
>Cc: Alim Akhtar <alim.akhtar=40samsung.com>; Linux ARM <linux-arm-
>kernel=40lists.infradead.org>; Linux Kernel Mailing List <linux-
>kernel=40vger.kernel.org>; SoC Team <soc=40kernel.org>; linux-clk <linux-
>clk=40vger.kernel.org>; DTML <devicetree=40vger.kernel.org>; Olof Johansso=
n
><olof=40lixom.net>; Linus Walleij <linus.walleij=40linaro.org>; Catalin Ma=
rinas
><catalin.marinas=40arm.com>; Rob Herring <robh+dt=40kernel.org>; Sylwester
>Nawrocki <s.nawrocki=40samsung.com>; moderated list:ARM/SAMSUNG
>EXYNOS ARM ARCHITECTURES <linux-samsung-soc=40vger.kernel.org>; Pankaj
>Dubey <pankaj.dubey=40samsung.com>; linux-fsd=40tesla.com; Arjun K V
><arjun.kv=40samsung.com>; Aswani Reddy <aswani.reddy=40samsung.com>;
>Ajay Kumar <ajaykumar.rs=40samsung.com>; Sriranjani P
><sriranjani.p=40samsung.com>; Chandrasekar R <rcsekar=40samsung.com>;
>Shashank Prashar <s.prashar=40samsung.com>; Arnd Bergmann
><arnd=40arndb.de>
>Subject: Re: =5BPATCH 14/23=5D arm64: dts: fsd: Add initial device tree su=
pport
>
>On Thu, Jan 13, 2022 at 2:16 PM Krzysztof Kozlowski
><krzysztof.kozlowski=40canonical.com> wrote:
>> >  ARM/TETON BGA MACHINE SUPPORT
>> >  M:   =22Mark F. Brown=22 <mark.brown314=40gmail.com>
>> >  L:   linux-arm-kernel=40lists.infradead.org (moderated for non-subscr=
ibers)
>> > diff --git a/arch/arm64/Kconfig.platforms
>> > b/arch/arm64/Kconfig.platforms index 54e3910e8b9b..bb8a047c2359
>> > 100644
>> > --- a/arch/arm64/Kconfig.platforms
>> > +++ b/arch/arm64/Kconfig.platforms
>> > =40=40 -267,6 +267,12 =40=40 config ARCH_TEGRA
>> >       help
>> >         This enables support for the NVIDIA Tegra SoC family.
>> >
>> > +config ARCH_TESLA_FSD
>> > +     bool =22ARMv8 based Tesla platform=22
>> > +     select ARCH_EXYNOS
>>
>> How similar it is? I think it is better to duplicate Exynos
>> selections/options here, instead of selecting entire ARCH. If this
>> would require =22depends on ARCH_EXYNOS =7C=7C ARCH_TESLA_FSD=22
>everywhere in
>> the drivers, it's a hint that it is not a separate SoC but it is an
>> Exynos, so it might not need a new sub-architecture.
>
>Agreed, the SoC family options mainly exist so we can quickly enable or
>disable drivers based on what a kernel is built for. If most of the driver=
s for
>this SoC are shared with Exynos, I think having a single option is suffici=
ent, but
>it may be worth pointing out both in the help text.
>
>If we want to have a separate option (mainly to help users find it), maybe=
 a
>'depends on ARCH_EXYNOS' would be better. How many uses of
>ARCH_TESLA_FSD are there?
>
It is true that FSD shares few IPs with Exynos and it dose contains Telsa s=
pecific IPs/ PCIe/some of the PHYs/ GPUs (different then Exynos) etc. to na=
me a few.
And drivers for those will be posted in upcoming phases by Samsung, Telsa e=
tc.
AFA architecture is concerns both Exynos and FSD has completely different a=
rchitecture (at least at HW level).
In my opinion, it is make sense to have a separate option for FSD.
And as Arnd suggested =22'depends on ARCH_EXYNOS=22 may be the way forward.

>        Arnd