From: Paul Burton <paulburton@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Chao-ying Fu <cfu@xxxxxxxxxxxx>
Signed-off-by: Dragan Mladjenovic <dragan.mladjenovic@xxxxxxxxxx>
Signed-off-by: Aleksandar Rikalo <arikalo@xxxxxxxxx>
Reviewed-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
Tested-by: Serge Semin <fancer.lancer@xxxxxxxxx>
Tested-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>
---
drivers/clocksource/mips-gic-timer.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
index 7907b740497a..abb685a080a5 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -115,6 +115,9 @@ 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;
}
@@ -288,9 +291,6 @@ 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
--
2.25.1
