[PATCH] arm: l2x0: add PMU support

[mark.rutland@arm.com (Mark Rutland)]

On Thu, Aug 18, 2016 at 07:05:46PM -0500, Kim Phillips wrote:
> On Wed, 17 Aug 2016 17:26:31 +0100
> Mark Rutland <mark.rutland@arm.com> wrote:
> 
> > The L2C-220 (AKA L220) and L2C-310 (AKA PL310) cache controllers feature
> > a Performance Monitoring Unit (PMU), which can be useful for tuning
> > and/or debugging. This hardware is always present and the relevant
> > registers are accessible to non-secure accesses. Thus, no special
> > firmware interface is necessary.
> > 
> > This patch adds support for the PMU, plugging into the usual perf
> > infrastructure. The overflow interrupt is not always available (e.g. on
> > RealView PBX A9 it is not wired up at all), and the hardware counters
> > saturate, so the driver does not make use of this. Instead, the driver
> > periodically polls and reset counters as required to avoid losing
> > events due to saturation.
> > 
> > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> > Cc: Kim Phillips <kim.phillips@arm.com>
> > Cc: Pawel Moll <pawel.moll@arm.com>
> > Cc: Russell King <linux@armlinux.org.uk>
> > Cc: Will Deacon <will.deacon@arm.com>
> > ---
> 
> FWIW, I was able to test this successfully on a pandaboard.

Great!

I've taken that as a Tested-by for v2 of the series [1], on the
assumption that you're happy with that.

Please give me a shout if that is not the case!

Thanks,
Mark.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/450024.html