diff --git a/README b/README
index 7f2506a..a73234e 100644
--- a/README
+++ b/README
@@ -3878,6 +3878,10 @@
 		If defined, the x86 reset vector code is included. This is not
 		needed when U-Boot is running from Coreboot.
 
+- CONFIG_SYS_MPUCLK
+		Defines the MPU clock speed (in MHz).
+
+		NOTE : currently only supported on AM335x platforms.
 
 Freescale QE/FMAN Firmware Support:
 -----------------------------------