linux-kernel - Re: [PATCH 1/8] arm64: dts: s32g2: Add the STM description

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <164402ad-2762-4d6b-aa34-38ff1b506600@linaro.org>
Date: Fri, 1 Aug 2025 10:35:04 +0200
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: Frank Li <Frank.li@....com>
Cc: mbrugger@...e.com, chester62515@...il.com,
 ghennadi.procopciuc@....nxp.com, shawnguo@...nel.org,
 s.hauer@...gutronix.de, s32@....com, kernel@...gutronix.de,
 festevam@...il.com, robh@...nel.org, krzk+dt@...nel.org,
 conor+dt@...nel.org, linux-arm-kernel@...ts.infradead.org,
 imx@...ts.linux.dev, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org,
 Ghennadi Procopciuc <ghennadi.procopciuc@....com>,
 Thomas Fossati <thomas.fossati@...aro.org>
Subject: Re: [PATCH 1/8] arm64: dts: s32g2: Add the STM description

On 01/08/2025 01:20, Frank Li wrote:
> On Wed, Jul 30, 2025 at 11:15:40PM +0200, Daniel Lezcano wrote:

[ ... ]

>>>> +			compatible = "nxp,s32g2-stm";
>>>> +			reg = <0x4011c000 0x3000>;
>>>> +			interrupts = <GIC_SPI 24 IRQ_TYPE_LEVEL_HIGH>;
>>>> +			clocks = <&clks 0x3b>, <&clks 0x3c>, <&clks 0x3c>;
>>>> +			clock-names = "counter", "module", "register";
>>>> +			status = "disabled";
>>>
>>> why not default enable.
>>
>> The S32G2 and S32G3 can have different variants with 2, 4, 8 Cortex-A53 and
>> 3 or 4 Cortex-M7. We enable the same number of CPUs present on the system.
>>
>> AFAIU:
>> 	S32G233A : 2 x Cortex-A53
>> 	S32G274A : 4 x Cortex-A53
>>
>> 	S32G399A : 8 x Cortex-A53
>> 	S32G379A : 4 x Cortex-A53
>>
>> Otherwise we would have to do the opposite, that is disable the unused ones
>> in the s32g274a-rdb2.dts, s32g399a-rdb3.dts and other dts which include the
>> s32g2.dtsi and s32g3.dtsi.
>>
> 
> That's fine by default disabled. but what's impact if it is enable but no
> one use it?

At the first glance I would say we call the probe function for nothing, 
so adding an extra overhead. When repeated into multiple drivers that 
increases the boot time significantly. It is certainly a good practice 
as a rule of thumb to enable only the ones we really need.

-- 
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog