Re: [PATCH 1/4] ARM: STi: add stid127 soc support

[srinivas kandagatla]

On 06/02/14 16:46, Arnd Bergmann wrote:
> On Wednesday 05 February 2014, srinivas kandagatla wrote:
>> Currently l2cc bindings has few optional properties like.
>>
>> - arm,data-latency
>> - arm,tag-latency
>> - arm,dirty-latency
>> - arm,filter-ranges
>> - interrupts :
>> - cache-id-part:
>> - wt-override:
>>
>> These does not include properties to set "way-size", "associativity",
>> "enabling prefetching", "Prefetch drop enable", "prefetch offset",
>> "Double linefill" and few more in prefect control register and
>> aux-control register.
>>
>> This is not just a issue with STi SOCs, having a quick look, I can see
>> that few more SOCs have similar requirements to set these properties.
>>
>> We could do two things to get l2 setup automatically on STi SOCS.
>>
>> 1> Either define these properties case-by-case basic, which might be
>> useful for other SOCs too.
>>
>> 2> Or Add new compatible string for STi SoCs so that they can
>> automatically setup these values in cache-l2x0.c
>>
>> Am Ok with either approaches.
>>
> 
> I suggested 1 in the past, but the objection that I saw (can't
> find the email at the moment) was that the additional settings
> are "configuration" rather than "hardware properties". What I'd
> really need to know from you is which of properties you listed
> as missing above are actually needed for your platform, and whether
> they can be classified as hardware specific or just configuration.

On STi Platforms we need below properties to got for option 1.
arm,way-size;
arm,instruction-prefetch-enable;
arm,data-prefetch-enable;

we also want a property or a way to set
"Shareable attribute Override Enable" bit in the Auxiliary Control
Register, bit[22].

Thanks,
srini
> 
> 	Arnd
> 
> 

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