From: Dragan Mladjenovic <Dragan.Mladjenovic@syrmia.com>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>,
Serge Semin <fancer.lancer@gmail.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
Chao-ying Fu <cfu@wavecomp.com>
Subject: [PATCH 08/12] clocksource: mips-gic-timer: Enable counter when CPUs start
Date: Thu, 19 May 2022 20:51:21 +0200 [thread overview]
Message-ID: <20220519185125.11686-9-Dragan.Mladjenovic@syrmia.com> (raw)
In-Reply-To: <20220519185125.11686-1-Dragan.Mladjenovic@syrmia.com>
From: Paul Burton <paulburton@kernel.org>
In multi-cluster MIPS I6500 systems we have 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 for us to clear COUNTSTOP
once in gic_clocksource_of_init() in order to start the counter, since
with only one cluster we know that we won't be resetting that cluster's
GIC at any point (ignoring suspend/resume cycles which would need to
handle clearing COUNTSTOP in the resume path). Once we support
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>
diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
index 6632d314a2c0..90a736a13115 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -119,6 +119,9 @@ 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;
}
@@ -289,9 +292,6 @@ 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
--
2.17.1
next prev parent reply other threads:[~2022-05-19 18:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-19 18:51 [PATCH 00/12] MIPS: Support I6500 multi-cluster configuration Dragan Mladjenovic
2022-05-19 18:51 ` [PATCH 01/12] MIPS: CPS: Add a couple of multi-cluster utility functions Dragan Mladjenovic
2022-05-19 18:51 ` [PATCH 02/12] MIPS: GIC: Generate redirect block accessors Dragan Mladjenovic
2022-05-19 18:51 ` [PATCH 03/12] irqchip: mips-gic: Introduce gic_with_each_online_cpu() Dragan Mladjenovic
2022-05-20 8:38 ` Marc Zyngier
2022-05-23 10:30 ` Serge Semin
2022-05-19 18:51 ` [PATCH 04/12] irqchip: mips-gic: Support multi-cluster in gic_with_each_online_cpu() Dragan Mladjenovic
2022-05-19 18:51 ` [PATCH 05/12] irqchip: mips-gic: Setup defaults in each cluster Dragan Mladjenovic
2022-05-19 18:51 ` [PATCH 06/12] irqchip: mips-gic: Multi-cluster support Dragan Mladjenovic
2022-05-19 18:51 ` [PATCH 07/12] clocksource: mips-gic-timer: Always use cluster 0 counter as clocksource Dragan Mladjenovic
2022-05-19 18:51 ` Dragan Mladjenovic [this message]
2022-05-19 18:51 ` [PATCH 09/12] MIPS: pm-cps: Use per-CPU variables as per-CPU, not per-core Dragan Mladjenovic
2022-05-19 18:51 ` [PATCH 10/12] MIPS: CPS: Introduce struct cluster_boot_config Dragan Mladjenovic
2022-05-19 18:51 ` [PATCH 11/12] MIPS: Report cluster in /proc/cpuinfo Dragan Mladjenovic
2022-05-19 18:51 ` [PATCH 12/12] MIPS: CPS: Boot CPUs in secondary clusters Dragan Mladjenovic
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