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Commit f16ff2bd authored by Matt Redfearn's avatar Matt Redfearn Committed by Daniel Lezcano
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clocksource/drivers/mips-gic-timer: Add fastpath for local timer updates 



Always accessing the compare register via the CM redirect region is
(relatively) slow. If the timer being updated is the current CPUs
then this can be shortcutted by writing to the CM VP local region.

Signed-off-by: default avatarMatt Redfearn <matt.redfearn@mips.com>
Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
parent 7957b07b

drivers/clocksource/mips-gic-timer.c

+7 −2
Original line number Diff line number Diff line
@@ -39,13 +39,18 @@ static u64 notrace gic_read_count(void) 


static int gic_next_event(unsigned long delta, struct clock_event_device *evt)

{

	int cpu = cpumask_first(evt->cpumask);

	u64 cnt;

	int res;



	cnt = gic_read_count();

	cnt += (u64)delta;

	write_gic_vl_other(mips_cm_vp_id(cpumask_first(evt->cpumask)));

	if (cpu == raw_smp_processor_id()) {

		write_gic_vl_compare(cnt);

	} else {

		write_gic_vl_other(mips_cm_vp_id(cpu));

		write_gic_vo_compare(cnt);

	}

	res = ((int)(gic_read_count() - cnt) >= 0) ? -ETIME : 0;

	return res;

}