Re: [PATCH v5 3/7] ARM: dts: Exynos542x/5800: add CPU OPP properties

From: Krzysztof Kozlowski
Date: Thu Dec 10 2015 - 23:00:48 EST


On 11.12.2015 12:32, Viresh Kumar wrote:
> On 11-12-15, 00:25, Javier Martinez Canillas wrote:
>> The problem is that the big and LITTLE cores have different ordering per SoCs:
>>
>> - Exynos5420 and Exynos5800: cpu0-3 (Cortex-A15) and cpu4-7 (Coretx-A7)
>> - Exynos5422: cpu0-3 (Cortex-A7) and cpu4-7 (Cortex-A15)
>>
>> So the OPP tables are set in this DTSI file, to prevent the OPP tables
>> in the Exynos5422 to be inverted for the cluster 0 and 1.
>
> Oh dude, that's really *ugly*. :)
>
> Reusing files/definitions is fine to the point where things are
> readable. But you have screwed it up so very badly.
>
> Over that, why can't you keep cpu0-3 as A7 and 4-7 as a15 for all the
> cases? The only worrying thing for you should be that CPU0 within the
> kenrel should be controllable, right? i.e. you want a A15 to boot 5800
> and A7 to boot 5422.
>
> If yes, than you could have kept the CPUs in 5422 as:
> 0-3: A7
> 4-7: A15
>
> and in 5420 as:
> 4-7: A15
> 0-3: A7
>
> Wouldnt' that work ?

It wasn't working like this. The cpu0 got the index from booting cpu, so
on 5420 cpu0 was A15 and on 5422 it was A7.

Maybe I am not aware of some changes recently in the kernel but how do
you want to assign the booting CPU proper number (not CPU0)?

Best regards,
Krzysztof

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