[PATCHv4] arm: l2x0: add PMU support

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

On Thu, Sep 01, 2016 at 04:38:02PM -0500, Kim Phillips wrote:
> On Thu, 1 Sep 2016 16:37:07 +0100
> Russell King - ARM Linux <linux@armlinux.org.uk> wrote:
> 
> > On Wed, Aug 31, 2016 at 03:23:36PM +0100, Mark Rutland 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>
> > > Acked-by: Pawel Moll <pawel.moll@arm.com>
> > > Cc: Kim Phillips <kim.phillips@arm.com>
> > > Cc: Russell King <linux@armlinux.org.uk>
> > > Cc: Will Deacon <will.deacon@arm.com>
> > 
> > Much better, thanks.  When you're happy, please put it in the patch
> > system, thanks.
> 
> feel free to tack on my:
> 
> Tested-by: Kim Phillips <kim.phillips@arm.com>

Cheers!

I've folded that in, and dropped this in the patch system as 8611/1.

Thanks,
Mark.