RE: [PATCH 00/16] Add support for the Axis ARTPEC-8 SoC

["Pankaj Dubey" <pankaj.dubey@samsung.com>]

> Subject: Re: [PATCH 00/16] Add support for the Axis ARTPEC-8 SoC
> 
> On 06/08/2025 10:22, Pankaj Dubey wrote:
> >
> >
> >> -----Original Message-----
> >> From: Krzysztof Kozlowski <krzk@kernel.org>
> >> Sent: Monday, July 21, 2025 12:10 PM
> >> To: SeonGu Kang <ksk4725@coasia.com>; Jesper Nilsson
> >> <jesper.nilsson@axis.com>; Michael Turquette
> <mturquette@baylibre.com>;
> >> Stephen Boyd <sboyd@kernel.org>; Rob Herring <robh@kernel.org>;
> >> Krzysztof Kozlowski <krzk+dt@kernel.org>; Conor Dooley
> >> <conor+dt@kernel.org>; Sylwester Nawrocki
> <s.nawrocki@samsung.com>;
> >> Chanwoo Choi <cw00.choi@samsung.com>; Alim Akhtar
> >> <alim.akhtar@samsung.com>; Linus Walleij <linus.walleij@linaro.org>;
> >> Tomasz Figa <tomasz.figa@gmail.com>; Catalin Marinas
> >> <catalin.marinas@arm.com>; Will Deacon <will@kernel.org>; Arnd
> Bergmann
> >> <arnd@arndb.de>
> >> Cc: kenkim <kenkim@coasia.com>; Jongshin Park <pjsin865@coasia.com>;
> >> GunWoo Kim <gwk1013@coasia.com>; HaGyeong Kim
> >> <hgkim05@coasia.com>; GyoungBo Min <mingyoungbo@coasia.com>;
> >> SungMin Park <smn1196@coasia.com>; Pankaj Dubey
> >> <pankaj.dubey@samsung.com>; Shradha Todi
> <shradha.t@samsung.com>;
> >> Ravi Patel <ravi.patel@samsung.com>; Inbaraj E
> <inbaraj.e@samsung.com>;
> >> Swathi K S <swathi.ks@samsung.com>; Hrishikesh
> >> <hrishikesh.d@samsung.com>; Dongjin Yang <dj76.yang@samsung.com>;
> >> Sang Min Kim <hypmean.kim@samsung.com>; linux-
> kernel@vger.kernel.org;
> >> linux-arm-kernel@lists.infradead.org; linux-samsung-
> soc@vger.kernel.org;
> >> linux-arm-kernel@axis.com; linux-clk@vger.kernel.org;
> >> devicetree@vger.kernel.org; linux-gpio@vger.kernel.org;
> soc@lists.linux.dev
> >> Subject: Re: [PATCH 00/16] Add support for the Axis ARTPEC-8 SoC
> >>
> >> On 21/07/2025 06:50, SeonGu Kang wrote:
> >>> 2025-07-10 (목), 09:07 +0200, Krzysztof Kozlowski:
> >>>> On 10/07/2025 02:20, ksk4725@coasia.com wrote:
> >>>>> From: SeonGu Kang <ksk4725@coasia.com>
> >>>>>
> >>>>> Add basic support for the Axis ARTPEC-8 SoC.
> >>>>> This SoC contains four Cortex-A53 CPUs and other several IPs.
> >>>>>
> >>>>> Patches 1 to 10 provide the support for the clock controller, which
> >>>>> is similar to other Samsung SoCs.
> >>>>>
> >>>> You should explain here (and in DTS patches or the bindings) the
> >>>> hardware, that this is Samsung SoC.
> >>>>
> >>>> You could also explain the differences from Exynos and proposed
> >>>> handling of patches (because this is odd)
> >>>>
> >>>> Also, entire patchset has wrong and incomplete SoBs. Your SoB is
> >>>> missing everywhere, others have wrong order.
> >>>>
> >>>> Please read submitting patches first.
> >>>>
> >>>
> >>> This Custom SoC is owned by the Axis (OEM) and manufactured by the
> >>> Samsung (ODM). It has standard Samsung specific IP blocks.
> >>
> >>
> >> It is designed by Samsung. It is Samsung SoC.
> >>
> >> Anyway, don't explain to me, but in your patchset.
> >
> > Hi Krzysztof,
> >
> > Thank you for your review comments on the ARTPEC-8 platform patches.
> > I'd like to add more context about the ARTPEC-8 SoC to help clarify its
> > relationship with Exynos.
> >
> > Here are the key details about ARTPEC-8:
> >    - Manufactured by Samsung Foundry
> >    - SoC architecture is owned by Axis Communications
> > 	- On similar model as Tesla's FSD chip owned by Tesla and
> >               manufactured and  by Samsung
> >    - IPs from both Samsung and Axis Communications
> >
> > Samsung-provided IPs:
> >   - UART
> >   - Ethernet (Vendor: Synopsys)
> >        - Same IP has been integrated as integrated in FSD Chip
> >   - SDIO
> >   - SPI
> >   - HSI2C
> >   - I2S
> >   - CMU (Clock Management Unit)
> >        Follows same CMU HW architecture as Exynos SoC have
> >   - Pinctrl (GPIO)
> >   - PCIe (Vendor: Synopsys)
> >        Though Exynos, FSD, ARTPEC have same DesignWare Controller,
> >        the glue/wrapper layer around DWC Core has differences across
> >        these SoCs. All manufactured by Samsung, but differences are there
> >        in HW design and for different products. For the same reason PCIe
> patch
> >        refactoring effort is being put by us [1] to streamline single Exynos
> driver
> >        which can support all Samsung manufactured SoCs having DWC PCIe
> controller.
> >       [1]: https://protect2.fireeye.com/v1/url?k=8a8233e4-d5190ae8-
> 8a83b8ab-000babff3563-7bd7c9980190e0e8&q=1&e=2e04cfd4-33cf-4f00-
> a970-
> 7dcbf1d780ec&u=https%3A%2F%2Fpatchwork.ozlabs.org%2Fproject%2Flinu
> x-pci%2Fpatch%2F20250625165229.3458-2-shradha.t%40samsung.com%2F
> 
> So entire base of the SoC is Samsung.

Yes, if we are saying this based on the core IPs (CMU, Pinctrl) and the fact that
it is manufactured by Samsung.

> 
> >
> > Axis-provided IPs:
> >     - VIP (Image Sensor Processing IP)
> >     - VPP (Video Post Processing)
> >     - GPU
> >     - CDC (Video Encoder)
> >
> > As part of the upstreaming effort, Samsung and Coasia (DSP) team will
> work together
> > to upstream basic SoC support and Samsung IPs support.
> > The Axis team will be the primary maintainer for the ARTPEC-8 SoC
> codebase.
> 
> Don't know what do you mean by "primary", but I want to be clear: this
> classifies as Samsung SoC, so I will be maintaining and overlooking it
> just like I maintain and take care about all Samsung SoCs. Otherwise you
> will be introducing errors and warnings or, in best case different
> style. And this already happened if I did not object!
> 

By "primary" I mean as it is product of Axis, and only Axis will be having access
to this SoCs in future they will be responsible to maintain it and add support for.

> Also SAME strict DT compliance profile will be applied. (see more on
> that below)
> 
> >
> > Given that ARTPEC-8 is a distinct SoC with its own set of IPs, we believe it's
> reasonable
> > to create a separate directory for it, similar to FSD.
> 
> No. It was a mistake for FSD to keep it separate why? Because there is
> no single non-Samsung stuff there. I am afraid exactly the same will
> happen there.
> 

I am not sure, why you are saying this as a mistake, in case next version of FSD
or ARTPEC is manufactured (ODM) by another vendor in that case, won't it
create problems? 

For example ARTPEC-6/7 (ARM based) have their own directories as "arch/arm/boot/dts/axis/"
These were not Samsung (ODM) manufactures SoCs. 

But ARTPEC-8/9 (ARM64) based SoCs are samsung manufactured. What if the next version say
ARTPEC-10 is not samsung manufactured, so different version of products (SoCs) from
same vendor (OEM), in this case Axis, will have code in separate directories and with different maintainers? 

> Based on above list of blocks this should be done like Google is done,
> so it goes as subdirectory of samsung (exynos). Can be called axis or
> artpec-8.

I will suggest to keep axis, knowing the fact that sooner after artpec-8 patches gets approved and merged
we have plan to upstream artpec-9 (ARM64, Samsung manufactured) as well.

> 
> To clarify: Only this SoC, not others which are not Samsung.
> 
> >
> > We will remove Samsung and Coasia teams from the maintainers list in v2
> and only
> > Axis team will be maintainer.
> 
> A bit unexpected or rather: just use names of people who WILL be
> maintaining it. If this is Jesper and Lars, great. Just don't add
> entries just because they are managers.

AFAIK, Jesper will be taking care. 

> 
> >
> > Maintainer list for previous generation of Axis chips (ARM based) is already
> present,
> > so this will be merged into that.
> 
> Existing Artpec entry does not have tree mentioned, so if you choose
> above, you must not add the tree, since the tree is provided by Samsung SoC.
> 

OK

> OTOH, how are you going to add there strict DT compliance? Existing axis
> is not following this, but artpec-8, as a Samsung derivative, MUST
> FOLLOW strict DT compliance. And this should be clearly marked in
> maintainer entry, just like everywhere else.
>

As I said this is tricky situation, though artpec-8 is derivative of samsung, we can't confirm 
if future versions (> 9) will be samsung derivative. 

But this would be case for all such custom ASIC manufactured by samsung, so I would like to
understand how this will be handled? 

> 
> >
> > Please let us know if this explanation addresses your concerns.
> > We'll update the commit message and cover letter accordingly.
> 
> 
> Best regards,
> Krzysztof