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Date: Fri, 11 Nov 2011 10:17:55 +0530
From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [PATCH] powerpc: Export PIR data through sysfs
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Cc: Scott Wood <scottwood@freescale.com>, linuxppc-dev@ozlabs.org,
 Anton Blanchard <anton@samba.org>, mahesh@linux.vnet.ibm.com
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On Fri, Nov 11, 2011 at 03:18:14PM +1100, Benjamin Herrenschmidt wrote:
> On Thu, 2011-11-10 at 14:18 +0530, Ananth N Mavinakayanahalli wrote:
> 
> > 
> > From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
> > 
> > The Processor Identification Register (PIR) on some powerpc platforms
> > provides information to decode the processor identification tag.
> > Decoding this information is platform specific.
> > 
> > We currently need this information for POWERx processors and hence
> > follows a similar model as adopted for the other POWERx specific
> > features.
> 
> At this rate we're going to end up with no bits left for CPU features
> way too quickly... Especially for something we only care about once at
> boot time.
>
> Wouldn't CPU_FTR_PPCAS_ARCH_V2 be a good enough test ?

/me checks Cell manuals... yes, that test would be good enough. I will
cook up a patch to use this.
 
> Can you tell us a bit more about the real use for that feature ? I still
> don't see what's the point of getting the underlying HW ID.

This is a requirement from the hardware system test folks for use with
their core, node and thread tests.

Ananth