From 3128b0a2e0cf6e07aa78e5f8cf7dd9cd59dc8174 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Wed, 29 Jan 2025 13:32:47 +0100 Subject: clocksource: mips-gic-timer: Enable counter when CPUs start MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Chao-ying Fu Signed-off-by: Dragan Mladjenovic Signed-off-by: Aleksandar Rikalo Reviewed-by: Philippe Mathieu-Daudé Tested-by: Serge Semin Tested-by: Gregory CLEMENT Acked-by: Daniel Lezcano Signed-off-by: Thomas Bogendoerfer --- drivers/clocksource/mips-gic-timer.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers') 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 -- cgit v1.2.3-59-g8ed1b