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clocksource: mips-gic-timer: Enable counter when CPUs start

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[ Upstream commit 3128b0a2e0cf6e07aa78e5f8cf7dd9cd59dc8174 ]

In multi-cluster MIPS I6500 systems there is a GIC in each cluster,
each with its own counter. When a cluster powers up the counter will
be stopped, with the COUNTSTOP bit set in the GIC_CONFIG register.

In single cluster systems, it has been fine to clear COUNTSTOP once
in gic_clocksource_of_init() to start the counter. In multi-cluster
systems, this will only have started the counter in the boot cluster,
and any CPUs in other clusters will find their counter stopped which
will break the GIC clock_event_device.

Resolve this by having CPUs clear the COUNTSTOP bit when they come
online, using the existing gic_starting_cpu() CPU hotplug callback. This
will allow CPUs in secondary clusters to ensure that the cluster's GIC
counter is running as expected.

Signed-off-by: Paul Burton <paulburton@kernel.org>
Signed-off-by: Chao-ying Fu <cfu@wavecomp.com>
Signed-off-by: Dragan Mladjenovic <dragan.mladjenovic@syrmia.com>
Signed-off-by: Aleksandar Rikalo <arikalo@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Tested-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Paul Burton
2025-01-29 13:32:47 +01:00
committed by Greg Kroah-Hartman
parent 2e1b3650f5
commit 06abee685c
1 changed files with 3 additions and 3 deletions
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6
drivers/clocksource/mips-gic-timer.c
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@@ -114,6 +114,9 @@ static void gic_update_frequency(void *data)
static int gic_starting_cpu(unsigned int cpu)
{
/* Ensure the GIC counter is running */
clear_gic_config(GIC_CONFIG_COUNTSTOP);
gic_clockevent_cpu_init(cpu, this_cpu_ptr(&gic_clockevent_device));
return 0;
}
@@ -248,9 +251,6 @@ static int __init gic_clocksource_of_init(struct device_node *node)
pr_warn("Unable to register clock notifier\n");
}
/* And finally start the counter */
clear_gic_config(GIC_CONFIG_COUNTSTOP);
/*
* It's safe to use the MIPS GIC timer as a sched clock source only if
* its ticks are stable, which is true on either the platforms with