diff --git a/arch/arm/plat-omap/include/mach/serial.h b/arch/arm/plat-omap/include/mach/serial.h
index cc6bfa5..515b89b 100644
--- a/arch/arm/plat-omap/include/mach/serial.h
+++ b/arch/arm/plat-omap/include/mach/serial.h
@@ -26,12 +26,12 @@
 #define OMAP1510_BASE_BAUD	(12000000/16)
 #define OMAP16XX_BASE_BAUD	(48000000/16)
 
-#define is_omap_port(p)	({int __ret = 0;			\
-			if (p == IO_ADDRESS(OMAP_UART1_BASE) ||	\
-			    p == IO_ADDRESS(OMAP_UART2_BASE) ||	\
-			    p == IO_ADDRESS(OMAP_UART3_BASE))	\
-				__ret = 1;			\
-			__ret;					\
+#define is_omap_port(pt)	({int __ret = 0;			\
+			if ((pt)->port.mapbase == OMAP_UART1_BASE ||	\
+			    (pt)->port.mapbase == OMAP_UART2_BASE ||	\
+			    (pt)->port.mapbase == OMAP_UART3_BASE)	\
+				__ret = 1;				\
+			__ret;						\
 			})
 
 #endif
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 9ccc563..47a6096 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2213,7 +2213,7 @@
 
 #ifdef CONFIG_ARCH_OMAP15XX
 	/* Workaround to enable 115200 baud on OMAP1510 internal ports */
-	if (cpu_is_omap1510() && is_omap_port((unsigned int)up->port.membase)) {
+	if (cpu_is_omap1510() && is_omap_port(up)) {
 		if (baud == 115200) {
 			quot = 1;
 			serial_out(up, UART_OMAP_OSC_12M_SEL, 1);