6.1-stable review patch. If anyone has any objections, please let me know.
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From: Paul Burton paulburton@kernel.org
[ 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 --- 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 b3ae38f367205..39c70b5ac44c9 100644 --- a/drivers/clocksource/mips-gic-timer.c +++ b/drivers/clocksource/mips-gic-timer.c @@ -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