2 files changed, 16 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/arm/arch_timer.txt b/Documentation/devicetree/bindings/arm/arch_timer.txt
index 37b2cafa4e52..256b4d8bab7b 100644
--- a/Documentation/devicetree/bindings/arm/arch_timer.txt
+++ b/Documentation/devicetree/bindings/arm/arch_timer.txt
@@ -22,6 +22,14 @@ to deliver its interrupts via SPIs.
 - always-on : a boolean property. If present, the timer is powered through an
   always-on power domain, therefore it never loses context.
 
+** Optional properties:
+
+- arm,cpu-registers-not-fw-configured : Firmware does not initialize
+  any of the generic timer CPU registers, which contain their
+  architecturally-defined reset values. Only supported for 32-bit
+  systems which follow the ARMv7 architected reset values.
+
+
 Example:
 
         timer {
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 55256e4fb641..6967cb026b9e 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -705,6 +705,14 @@ static void __init arch_timer_init(struct device_node *np)
         arch_timer_detect_rate(NULL, np);
 
         /*
+         * If we cannot rely on firmware initializing the timer registers then
+         * we should use the physical timers instead.
+         */
+        if (IS_ENABLED(CONFIG_ARM) &&
+            of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
+                        arch_timer_use_virtual = false;
+
+        /*
          * If HYP mode is available, we know that the physical timer
          * has been configured to be accessible from PL1. Use it, so
          * that a guest can use the virtual timer instead.