diff --git a/README b/README
index 7f2506a9b9..a73234efdc 100644
--- a/README
+++ b/README
@@ -3878,6 +3878,10 @@ Low Level (hardware related) configuration options:
 		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:
 -----------------------------------
diff --git a/arch/arm/include/asm/arch-am33xx/clocks_am33xx.h b/arch/arm/include/asm/arch-am33xx/clocks_am33xx.h
index d748dd2787..2d960070f1 100644
--- a/arch/arm/include/asm/arch-am33xx/clocks_am33xx.h
+++ b/arch/arm/include/asm/arch-am33xx/clocks_am33xx.h
@@ -21,8 +21,11 @@
 
 #define OSC	(V_OSCK/1000000)
 
-/* MAIN PLL Fdll = 550 MHZ, */
-#define MPUPLL_M	550
+/* MAIN PLL Fdll = 550 MHz, by default */
+#ifndef CONFIG_SYS_MPUCLK
+#define CONFIG_SYS_MPUCLK	550
+#endif
+#define MPUPLL_M	CONFIG_SYS_MPUCLK
 #define MPUPLL_N	(OSC-1)
 #define MPUPLL_M2	1