[PATCH] omap3: beagle: Use GPTIMERi 1 for clockevents

[Premi, Sanjeev]

> -----Original Message-----
> From: linux-omap-owner at vger.kernel.org 
> [mailto:linux-omap-owner at vger.kernel.org] On Behalf Of Koen Kooi
> Sent: Sunday, June 26, 2011 1:41 AM
> To: linux-omap at vger.kernel.org List
> Cc: linux-arm-kernel; Paul Walmsley
> Subject: Re: [PATCH] omap3: beagle: Use GPTIMERi 1 for clockevents
> 
> 
> Op 25 jun 2011, om 20:51 heeft Premi, Sanjeev het volgende geschreven:
> 
> >> -----Original Message-----
> >> From: linux-omap-owner at vger.kernel.org 
> >> [mailto:linux-omap-owner at vger.kernel.org] On Behalf Of Koen Kooi
> >> Sent: Saturday, June 25, 2011 1:47 PM
> >> To: linux-omap at vger.kernel.org List
> >> Cc: linux-arm-kernel; Paul Walmsley
> >> Subject: Re: [PATCH] omap3: beagle: Use GPTIMERi 1 for clockevents
> >> 
> >> 
> >> Op 24 jun 2011, om 18:23 heeft Sanjeev Premi het volgende 
> geschreven:
> >> 
> >>> The current selection of the GPTIMER on was result of
> >>> a hardware issue in early versions of the Beagleboards
> >>> (Ax and B1 thru B4). [1] [2]
> >>> 
> >>> Its been long since the hardware issue has been fixed.
> >>> This patch uses GPTIMER 1 for all newer board revisions
> >>> incl. Beagleboard XM.
> > 
> > [sp] I didn't include a reason - because the problem may not
> >     be reproducible on the public trees.
> > 
> >     During tests performed in internal development trees, the
> >     BogoMIPS calculations @ 1GHz wouldn't go beyond "830-850"
> >     range. While there was no such inconsistency on OMAP3EVM.
> > 
> >     After few days of debug GPTIMER12 came to be only difference.
> >     Tracing GPTIMER12 in the spec proved quite a challenge; the
> >     as timer is not included in the TRM and corresponding interrupt
> >     is marked reserved. Paul (in cc:) obviously had access to
> >     documents that we don't.
> > 
> >     This patch is merely trying to bring parity in use of GPTIMER
> >     across OMAP3 boards (AND use documented IP) - taking note of
> >     many Beagleboards where current code is necessary.
> 
> I get a value of 1010 ±10 bogoMIPS consistently with .39 + 
> dvfs patches. Having said that, this patch does seem to be an 
> improvement, but has it actually been tested on real 
> beagleboard hardware with a recent kernel?

[sp] It was tested on BeagleXM RevB on top of linux-omap master - as
     on day of submitting th patch.

> Especially on the 
> boards affected by the capacitor issue on the external clock.--

[sp] The patch relies on the check for board revision to continue using
     GPTIMER12 on affected boards - which I am assuming to be right.

     I don't have access to any of these versions, trying to find some
     early users. Hope someone on the list with Ax/Bx version can share
     the result...

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