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

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 <redacted>
---

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;