[PATCH 0/2] Control PL310 pwr_ctrl register through DT

[Brad Mouring]

During some performance-oriented benchmarking on a Cortex A9
platform, a slight performance degradation was noted on datasets
that spanned into the L2 cache (<10%). This performance hit was
minor, but it prompted investigation into the cause.

One difference in the actual PL310 configuration that was concerning
was the enabling of two PM-related changes: Dynamic Clock Gating
and Standby Mode Enabling. As the kernel being tested was patched
and configured to use the PREEMPT_RT patchset, it was desired to
disable these settings for our use-case since anything PM can
(and usually does) impact determinism.

Making these changes resulted in a modest performance improvement
and those wonderful warm-n-fuzzies regarding determinism and enabling
system control without needing to change the kernel.

In the following set, there's the actual change to control these
features given DT presence of a couple of new bindings and the
documenation to accompany those changes. Thanks!