diff --git a/arch/sh/kernel/cpu/sh3/setup-sh770x.c b/arch/sh/kernel/cpu/sh3/setup-sh770x.c
index 4551ad647c2c..6d549792f791 100644
--- a/arch/sh/kernel/cpu/sh3/setup-sh770x.c
+++ b/arch/sh/kernel/cpu/sh3/setup-sh770x.c
@@ -108,6 +108,7 @@ static struct platform_device rtc_device = {
 
 static struct plat_sci_port scif0_platform_data = {
 	.mapbase	= 0xfffffe80,
+	.port_reg	= 0xa4000136,
 	.flags		= UPF_BOOT_AUTOCONF,
 	.scscr		= SCSCR_TE | SCSCR_RE,
 	.scbrr_algo_id	= SCBRR_ALGO_2,
diff --git a/arch/sh/kernel/cpu/sh4/setup-sh7750.c b/arch/sh/kernel/cpu/sh4/setup-sh7750.c
index e53b4b38bd11..8ea26e791187 100644
--- a/arch/sh/kernel/cpu/sh4/setup-sh7750.c
+++ b/arch/sh/kernel/cpu/sh4/setup-sh7750.c
@@ -38,6 +38,7 @@ static struct platform_device rtc_device = {
 
 static struct plat_sci_port sci_platform_data = {
 	.mapbase	= 0xffe00000,
+	.port_reg	= 0xffe0001C
 	.flags		= UPF_BOOT_AUTOCONF,
 	.scscr		= SCSCR_TE | SCSCR_RE,
 	.scbrr_algo_id	= SCBRR_ALGO_2,
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index bb27885ea2e5..3248ddaa889d 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -363,6 +363,19 @@ static int sci_rxfill(struct uart_port *port)
 	return (sci_in(port, SCxSR) & SCxSR_RDxF(port)) != 0;
 }
 
+/*
+ * SCI helper for checking the state of the muxed port/RXD pins.
+ */
+static inline int sci_rxd_in(struct uart_port *port)
+{
+	struct sci_port *s = to_sci_port(port);
+
+	if (s->cfg->port_reg <= 0)
+		return 1;
+
+	return !!__raw_readb(s->cfg->port_reg);
+}
+
 /* ********************************************************************** *
  *                   the interrupt related routines                       *
  * ********************************************************************** */
diff --git a/drivers/tty/serial/sh-sci.h b/drivers/tty/serial/sh-sci.h
index caab353a98b5..1c20f7f9ba4f 100644
--- a/drivers/tty/serial/sh-sci.h
+++ b/drivers/tty/serial/sh-sci.h
@@ -287,32 +287,3 @@ SCIF_FNS(SCLSR,                         0,  0, 0x24, 16)
 #endif
 #define sci_in(port, reg) sci_##reg##_in(port)
 #define sci_out(port, reg, value) sci_##reg##_out(port, value)
-
-#if defined(CONFIG_CPU_SUBTYPE_SH7706) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7707) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7708) || \
-    defined(CONFIG_CPU_SUBTYPE_SH7709)
-static inline int sci_rxd_in(struct uart_port *port)
-{
-	if (port->mapbase == 0xfffffe80)
-		return __raw_readb(SCPDR)&0x01 ? 1 : 0; /* SCI */
-	return 1;
-}
-#elif defined(CONFIG_CPU_SUBTYPE_SH7750)  || \
-      defined(CONFIG_CPU_SUBTYPE_SH7751)  || \
-      defined(CONFIG_CPU_SUBTYPE_SH7751R) || \
-      defined(CONFIG_CPU_SUBTYPE_SH7750R) || \
-      defined(CONFIG_CPU_SUBTYPE_SH7750S) || \
-      defined(CONFIG_CPU_SUBTYPE_SH7091)
-static inline int sci_rxd_in(struct uart_port *port)
-{
-	if (port->mapbase == 0xffe00000)
-		return __raw_readb(SCSPTR1)&0x01 ? 1 : 0; /* SCI */
-	return 1;
-}
-#else /* default case for non-SCI processors */
-static inline int sci_rxd_in(struct uart_port *port)
-{
-	return 1;
-}
-#endif
diff --git a/include/linux/serial_sci.h b/include/linux/serial_sci.h
index 5fac3bccfd87..ecefec7c0b67 100644
--- a/include/linux/serial_sci.h
+++ b/include/linux/serial_sci.h
@@ -86,6 +86,8 @@ struct plat_sci_port {
 	int		overrun_bit;
 	unsigned int	error_mask;
 
+	int		port_reg;
+
 	struct device	*dma_dev;
 
 	unsigned int	dma_slave_tx;