lkml.org 
[lkml]   [2014]   [Feb]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/4] ARM: STi: add stid127 soc support
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
>
>



\
 
 \ /
  Last update: 2014-02-05 13:41    [W:2.040 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site