serial: imx: Enable UCR4_OREN in startup interface

[ Upstream commit 6f026d6b ]

Other than enable Receiver Overrun Interrupt Enable (UCR4_OREN)
in start_tx interface, UCR4_OREN should be enabled before enable
of Receiver.
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

drivers/tty/serial/imx.c

@@ -590,13 +590,6 @@ static void imx_start_tx(struct uart_port *port)
 		temp &= ~(UCR1_RRDYEN);
 		writel(temp, sport->port.membase + UCR1);
 	}
-	/* Clear any pending ORE flag before enabling interrupt */
-	temp = readl(sport->port.membase + USR2);
-	writel(temp | USR2_ORE, sport->port.membase + USR2);
-
-	temp = readl(sport->port.membase + UCR4);
-	temp |= UCR4_OREN;
-	writel(temp, sport->port.membase + UCR4);
 
 	if (!sport->dma_is_enabled) {
 		temp = readl(sport->port.membase + UCR1);
@@ -1156,6 +1149,14 @@ static int imx_startup(struct uart_port *port)
 
 	writel(temp, sport->port.membase + UCR1);
 
+	/* Clear any pending ORE flag before enabling interrupt */
+	temp = readl(sport->port.membase + USR2);
+	writel(temp | USR2_ORE, sport->port.membase + USR2);
+
+	temp = readl(sport->port.membase + UCR4);
+	temp |= UCR4_OREN;
+	writel(temp, sport->port.membase + UCR4);
+
 	temp = readl(sport->port.membase + UCR2);
 	temp |= (UCR2_RXEN | UCR2_TXEN);
 	if (!sport->have_rtscts)