arm64: arch_timer: Workaround for Cortex-A73 erratum 858921
Cortex-A73 (all versions) counter read can return a wrong value
when the counter crosses a 32bit boundary.
The workaround involves performing the read twice, and to return
one or the other depending on whether a transition has taken place.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 3356ab8..af80a7c 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -366,6 +366,17 @@
161010101. The workaround will be active if the hisilicon,erratum-161010101
property is found in the timer node.
+config ARM64_ERRATUM_858921
+ bool "Workaround for Cortex-A73 erratum 858921"
+ default y
+ select ARM_ARCH_TIMER_OOL_WORKAROUND
+ depends on ARM_ARCH_TIMER && ARM64
+ help
+ This option enables a workaround applicable to Cortex-A73
+ (all versions), whose counter may return incorrect values.
+ The workaround will be dynamically enabled when an affected
+ core is detected.
+
config ARM_GLOBAL_TIMER
bool "Support for the ARM global timer" if COMPILE_TEST
select CLKSRC_OF if OF