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

[Krzysztof Kozlowski <krzk@kernel.org>]

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://patchwork.ozlabs.org/project/linux-pci/patch/20250625165229.3458-2-shradha.t@samsung.com/

So entire base of the SoC is 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!

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.

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.

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.

> 
> 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.

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.


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


Best regards,
Krzysztof