[PATCH v5 3/5] arm64: arch_timer: Work around QorIQ Erratum A-008585

On Tue, 2016-09-20 at 10:35 +0100, Mark Rutland wrote:

On Mon, Sep 19, 2016 at 02:16:00PM -0500, Scott Wood wrote:

quoted

On Mon, 2016-09-19 at 18:07 +0100, Mark Rutland wrote:

quoted

quoted

quoted

Reconsidering my suggestion, I realise this will also affect the
MMIO
timers, so that doesn't work.

So for the moment, I guess we have to keep
fsl_a008585_set_next_event().

What is the problem with MMIO timers? ?needs_fsl_a008585_workaround()
should
always be false for them.

As suggested, needs_fsl_a008585_workaround() takes no parameter, and
set_next_event is called for both cp15/sysreg and MMIO timers. So it
would either be true for all, or false for all.

If it's true for all, we'd end up calling fsl_a008585_set_next_event()
for the MMIO timers too.

There should not be any MMIO timers on a system where
fsl_a008585_set_next_event() returns true.

I'm generally not keen on relying on that.

For reference, are no MMIO timers implemented at all, or are they simply
not listed in the DT today?

As far as I can tell they're not implemented, but it's possible I'm just not
looking at the right documentation. ?

I agree though that depending on that isn't particularly pretty. ?I'll stick
with the current approach for set_next_event().

-Scott