linux-kernel - Re: [PATCH v1 2/2] ARM: dts: samsung: Add cache information to the Exynos542x SoC

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Message-ID: <a41a6143-ef2e-4d86-b102-eaf442985173@kernel.org>
Date: Tue, 30 Jul 2024 14:27:19 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Anand Moon <linux.amoon@...il.com>,
 Marek Szyprowski <m.szyprowski@...sung.com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, Alim Akhtar <alim.akhtar@...sung.com>,
 devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/2] ARM: dts: samsung: Add cache information to the
 Exynos542x SoC

On 30/07/2024 14:06, Anand Moon wrote:
> Hi Marek,
> 
> On Tue, 30 Jul 2024 at 17:14, Marek Szyprowski <m.szyprowski@...sung.com> wrote:
>>
>>
>> On 30.07.2024 11:13, Anand Moon wrote:
>>> As per Exynos 5422 user manual add missing cache information to
>>> the Exynos542x SoC.
>>>
>>> - Each Cortex-A7 core has 32 KB of instruction cache and
>>>       32 KB of L1 data cache available.
>>> - Each Cortex-A15 core has 32 KB of L1 instruction cache and
>>>       32 KB of L1 data cache available.
>>> - The little (A7) cluster has 512 KB of unified L2 cache available.
>>> - The big (A15) cluster has 2 MB of unified L2 cache available.
>>>
>>> Features:
>>> - Exynos 5422 support cache coherency interconnect (CCI) bus with
>>>    L2 cache snooping capability. This hardware automatic L2 cache
>>>    snooping removes the efforts of synchronizing the contents of the
>>>    two L2 caches in core switching event.
>>>
>>> Signed-off-by: Anand Moon <linux.amoon@...il.com>
>>
>>
>> The provided values are not correct. Please refer to commit 5f41f9198f29
>> ("ARM: 8864/1: Add workaround for I-Cache line size mismatch between CPU
>> cores"), which adds workaround for different l1 icache line size between
>> big and little CPUs. This workaround gets enabled on all Exynos542x/5800
>> boards.
>>
> Ok, I have just referred to the Exynos 5422 user manual for this patch,
> This patch is just updating the cache size for CPU for big.litle architecture..
> 

Let me get it right. Marek's comment was that you used wrong values.
Marek also provided rationale for this. Now your reply is that you
update cache size? Sorry, I fail how you address Marek's comment.

Do not repeat what the patch is doing. We all can see it. Instead
respond to the comment with some sort of arguments.

Best regards,
Krzysztof