diff --git a/arch/m68k/include/asm/m523xsim.h b/arch/m68k/include/asm/m523xsim.h
index 6be94f6831ae..6e5c17a4bcb5 100644
--- a/arch/m68k/include/asm/m523xsim.h
+++ b/arch/m68k/include/asm/m523xsim.h
@@ -58,10 +58,19 @@
 /*
  *  UART module.
  */
-#define MCFUART_BASE1		0x200           /* Base address of UART1 */
-#define MCFUART_BASE2		0x240           /* Base address of UART2 */
-#define MCFUART_BASE3		0x280           /* Base address of UART3 */
+#define MCFUART_BASE1		(MCF_IPSBAR + 0x200)
+#define MCFUART_BASE2		(MCF_IPSBAR + 0x240)
+#define MCFUART_BASE3		(MCF_IPSBAR + 0x280)
 
+/*
+ *  FEC ethernet module.
+ */
+#define	MCFFEC_BASE		(MCF_IPSBAR + 0x1000)
+#define	MCFFEC_SIZE		0x800
+
+/*
+ *  GPIO module.
+ */
 #define MCFGPIO_PODR_ADDR	(MCF_IPSBAR + 0x100000)
 #define MCFGPIO_PODR_DATAH	(MCF_IPSBAR + 0x100001)
 #define MCFGPIO_PODR_DATAL	(MCF_IPSBAR + 0x100002)
diff --git a/arch/m68knommu/platform/523x/config.c b/arch/m68knommu/platform/523x/config.c
index 8980f6d7715a..418a76feb1e3 100644
--- a/arch/m68knommu/platform/523x/config.c
+++ b/arch/m68knommu/platform/523x/config.c
@@ -28,15 +28,15 @@
 
 static struct mcf_platform_uart m523x_uart_platform[] = {
 	{
-		.mapbase	= MCF_MBAR + MCFUART_BASE1,
+		.mapbase	= MCFUART_BASE1,
 		.irq		= MCFINT_VECBASE + MCFINT_UART0,
 	},
 	{
-		.mapbase 	= MCF_MBAR + MCFUART_BASE2,
+		.mapbase 	= MCFUART_BASE2,
 		.irq		= MCFINT_VECBASE + MCFINT_UART0 + 1,
 	},
 	{
-		.mapbase 	= MCF_MBAR + MCFUART_BASE3,
+		.mapbase 	= MCFUART_BASE3,
 		.irq		= MCFINT_VECBASE + MCFINT_UART0 + 2,
 	},
 	{ },
@@ -50,8 +50,8 @@ static struct platform_device m523x_uart = {
 
 static struct resource m523x_fec_resources[] = {
 	{
-		.start		= MCF_MBAR + 0x1000,
-		.end		= MCF_MBAR + 0x1000 + 0x7ff,
+		.start		= MCFFEC_BASE,
+		.end		= MCFFEC_BASE + MCFFEC_SIZE - 1,
 		.flags		= IORESOURCE_MEM,
 	},
 	{