Messages in this thread | | | Date | Wed, 5 Feb 2014 11:48:24 +0000 | From | srinivas kandagatla <> | Subject | Re: [PATCH 1/4] ARM: STi: add stid127 soc support |
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Hi Arnd, On 31/01/14 20:15, Arnd Bergmann wrote: > On Friday 31 January 2014, srinivas kandagatla wrote: > >>> Sorry if I missed the initial review, but can you explain >>> why this is needed to start with? >> >> On ST SoCs the default value for L2 AUX_CTRL register is 0x0, so we set >> the way-size explicit here. > > Unfortunately, we keep going back and forth on the L2 cache controller > setup between "it should work automatically" and "we don't want to > have configuration data in DT", where my personal opinion is that > the first one is more important here. > > Now, there are a couple of properties that are defined in > Documentation/devicetree/bindings/arm/l2cc.txt to let some of the > things get set up automatically already. Can you check which bits > are missing there, if any? Are they better described as "configuration" > or "hardware" settings?
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.
Thanks, srini
> > Arnd > >
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