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[v5,5/8] clocksource: dw_apb_timer: Affiliate of-based timer with any CPU

Message ID 20200521204818.25436-6-Sergey.Semin@baikalelectronics.ru
State Not Applicable
Headers show
Series clocksource: Fix MIPS GIC and DW APB Timer for Baikal-T1 SoC support | expand

Commit Message

Serge Semin May 21, 2020, 8:48 p.m. UTC
Currently any DW APB Timer device detected in OF is bound to CPU #0.
Doing so is redundant since DW APB Timer isn't CPU-local timer, but as
having APB interface is normally accessible from any CPU in the system. By
artificially affiliating the DW timer to the very first CPU we may and in
our case will make the clockevent subsystem to decline the more performant
real CPU-local timers selection in favor of in fact non-local and
accessible over a slow bus - DW APB Timers.

Let's not affiliate the of-detected DW APB Timers to any CPU. By doing so
the clockevent framework would prefer to select the real CPU-local timer
instead of DW APB one. Otherwise if there is no other than DW APB device
for clockevents tracking then it will be selected.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: devicetree@vger.kernel.org


Changelog v5:
- This is a new patch created after reconsidering the solution of the DW
  APB Timer CPU-affiliation problem.
 drivers/clocksource/dw_apb_timer_of.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index 8c28b127759f..2db490f35c20 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -73,7 +73,7 @@  static void __init add_clockevent(struct device_node *event_timer)
 	timer_get_base_and_rate(event_timer, &iobase, &rate);
-	ced = dw_apb_clockevent_init(0, event_timer->name, 300, iobase, irq,
+	ced = dw_apb_clockevent_init(-1, event_timer->name, 300, iobase, irq,
 	if (!ced)
 		panic("Unable to initialise clockevent device");