[RFC PATCH] clocksource: arm_arch_timer: disable the evtstrm via the cmdline

[Will Deacon]

Disabling the eventstream can be useful for debugging and development
purposes and is currently controlled via a Kconfig option
(CONFIG_ARM_ARCH_TIMER_EVTSTREAM). Whilst this does the trick, it's
often desirable to toggle the feature on the command line, so this patch
adds a "noevtstrm" command line option to do just that.

Signed-off-by: Will Deacon <will.deacon at arm.com>
---

Sending as an RFC because we might want to remove the Kconfig option
altogether if we have this.

 drivers/clocksource/arm_arch_timer.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 4814446a0024..f579c0da7423 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -79,6 +79,15 @@ static enum ppi_nr arch_timer_uses_ppi = VIRT_PPI;
 static bool arch_timer_c3stop;
 static bool arch_timer_mem_use_virtual;
 
+static bool evtstrm_disable;
+
+static int __init early_evtstrm_disable(char *buf)
+{
+	evtstrm_disable = true;
+	return 0;
+}
+early_param("noevtstrm", early_evtstrm_disable);
+
 /*
  * Architected system timer support.
  */
@@ -372,7 +381,7 @@ static int arch_timer_setup(struct clock_event_device *clk)
 		enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);
 
 	arch_counter_set_user_access();
-	if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM))
+	if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM) && !evtstrm_disable)
 		arch_timer_configure_evtstream();
 
 	return 0;
-- 
2.1.4