--- 18130f11238e6025b16682c9a00cca218727e370
+++ 2b550182a879db10044bc177649140bd52441033
@@ -119,7 +119,8 @@
 #define  MX2_UCR3_RXDMUXSEL	 (1<<2)  /* RXD Muxed Input Select, on mx2/mx3 */
 #define  UCR3_INVT  	 (1<<1)  /* Inverted Infrared transmission */
 #define  UCR3_BPEN  	 (1<<0)  /* Preset registers enable */
-#define  UCR4_CTSTL_32   (32<<10) /* CTS trigger level (32 chars) */
+#define  UCR4_CTSTL_SHF  10      /* CTS trigger level shift */
+#define  UCR4_CTSTL_MASK 0x3F    /* CTS trigger is 6 bits wide */
 #define  UCR4_INVR  	 (1<<9)  /* Inverted infrared reception */
 #define  UCR4_ENIRI 	 (1<<8)  /* Serial infrared interrupt enable */
 #define  UCR4_WKEN  	 (1<<7)  /* Wake interrupt enable */
@@ -590,6 +591,9 @@ static int imx_setup_ufcr(struct imx_por
 	return 0;
 }
 
+/* half the RX buffer size */
+#define CTSTL 16
+
 static int imx_startup(struct uart_port *port)
 {
 	struct imx_port *sport = (struct imx_port *)port;
@@ -606,6 +610,10 @@ static int imx_startup(struct uart_port
 	if (USE_IRDA(sport))
 		temp |= UCR4_IRSC;
 
+	/* set the trigger level for CTS */
+	temp &= ~(UCR4_CTSTL_MASK<<  UCR4_CTSTL_SHF);
+	temp |= CTSTL<<  UCR4_CTSTL_SHF;
+
 	writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
 
 	if (USE_IRDA(sport)) {
@@ -1279,7 +1287,7 @@ static int serial_imx_probe(struct platf
 		sport->use_irda = 1;
 #endif
 
-	if (pdata->init) {
+	if (pdata && pdata->init) {
 		ret = pdata->init(pdev);
 		if (ret)
 			goto clkput;
@@ -1292,7 +1300,7 @@ static int serial_imx_probe(struct platf
 
 	return 0;
 deinit:
-	if (pdata->exit)
+	if (pdata && pdata->exit)
 		pdata->exit(pdev);
 clkput:
 	clk_put(sport->clk);
@@ -1321,7 +1329,7 @@ static int serial_imx_remove(struct plat
 
 	clk_disable(sport->clk);
 
-	if (pdata->exit)
+	if (pdata && pdata->exit)
 		pdata->exit(pdev);
 
 	iounmap(sport->port.membase);