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Date:   Thu, 17 May 2018 18:55:26 +0200 (CEST)
From:   Stefan Wahren <stefan.wahren@i2se.com>
To:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>
Cc:     Florian Fainelli <f.fainelli@gmail.com>,
        linux-rpi-kernel@lists.infradead.org,
        bcm-kernel-feedback-list@broadcom.com,
        Vince Weaver <vincent.weaver@maine.edu>,
        linux-kernel@vger.kernel.org, Eric Anholt <eric@anholt.net>,
        linux-arm-kernel@lists.infradead.org
Message-ID: <307323036.63872.1526576126537@email.1und1.de>
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 <1412187220.62585.1526572780332@email.1und1.de>
 <alpine.DEB.2.21.1805171233500.7984@macbook-air>
Subject: Re: [PATCH] arm: bcm2835: Add the PMU to the devicetree.
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Hi,

[added Peter, Ingo and Arnaldo]

> Vince Weaver <vincent.weaver@maine.edu> hat am 17. Mai 2018 um 18:34 geschrieben:
> 
> 
> On Thu, 17 May 2018, Stefan Wahren wrote:
> 
> > 
> > > Eric Anholt <eric@anholt.net> hat am 17. Mai 2018 um 15:17 geschrieben:
> > > 
> > > 
> > > The a53 and a7 counters seem to match up, so we advertise a7 so that
> > > arm32 can probe.
> 
> so how closely did you look at the a53/a7 differences?  I see some major 
> differences, especially with the CPU_CYCLES event (0xff vs 0x11).
> 
> The proper fix here might be to add a cortex-a53 PMU entry to the armv7 
> code rather than trying to treat it as a cortex-a7.

we like to use the PMU of BCM2837 SoC (4x A53 cores) under arm32 and arm64.

What is the right way (tm) to the define the DT compatibles?
Does the arm32 PMU driver need patching for proper A53 support?

Stefan

> 
> Vince