tty: serial: imx: remove imx_disable_rx_int

Since imx_disable_rx_int is only called by imx_startup,
let's integrate it into that function. Notice UCR2_ATEN is
never set by the driver. The bit is still cleaned to make
this patch a noop.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/imx.c

@@ -703,25 +703,6 @@ out:
 	return IRQ_HANDLED;
 }
 
-static void imx_disable_rx_int(struct imx_port *sport)
-{
-	unsigned long temp;
-
-	/* disable the receiver ready and aging timer interrupts */
-	temp = readl(sport->port.membase + UCR1);
-	temp &= ~(UCR1_RRDYEN);
-	writel(temp, sport->port.membase + UCR1);
-
-	temp = readl(sport->port.membase + UCR2);
-	temp &= ~(UCR2_ATEN);
-	writel(temp, sport->port.membase + UCR2);
-
-	/* disable the rx errors interrupts */
-	temp = readl(sport->port.membase + UCR4);
-	temp &= ~UCR4_OREN;
-	writel(temp, sport->port.membase + UCR4);
-}
-
 static void clear_rx_errors(struct imx_port *sport);
 
 /*
@@ -1252,18 +1233,21 @@ static int imx_startup(struct uart_port *port)
 	if (sport->dma_is_inited && !sport->dma_is_enabled)
 		imx_enable_dma(sport);
 
-	temp = readl(sport->port.membase + UCR1);
-	temp |= UCR1_RRDYEN | UCR1_UARTEN;
+	temp = readl(sport->port.membase + UCR1) & ~UCR1_RRDYEN;
+	if (!sport->dma_is_enabled)
+		temp |= UCR1_RRDYEN;
+	temp |= UCR1_UARTEN;
 	if (sport->have_rtscts)
 			temp |= UCR1_RTSDEN;
 
 	writel(temp, sport->port.membase + UCR1);
 
-	temp = readl(sport->port.membase + UCR4);
-	temp |= UCR4_OREN;
+	temp = readl(sport->port.membase + UCR4) & ~UCR4_OREN;
+	if (!sport->dma_is_enabled)
+		temp |= UCR4_OREN;
 	writel(temp, sport->port.membase + UCR4);
 
-	temp = readl(sport->port.membase + UCR2);
+	temp = readl(sport->port.membase + UCR2) & ~UCR2_ATEN;
 	temp |= (UCR2_RXEN | UCR2_TXEN);
 	if (!sport->have_rtscts)
 		temp |= UCR2_IRTS;
@@ -1297,10 +1281,8 @@ static int imx_startup(struct uart_port *port)
 	 * In our iMX53 the average delay for the first reception dropped from
 	 * approximately 35000 microseconds to 1000 microseconds.
 	 */
-	if (sport->dma_is_enabled) {
-		imx_disable_rx_int(sport);
+	if (sport->dma_is_enabled)
 		start_rx_dma(sport);
-	}
 
 	spin_unlock_irqrestore(&sport->port.lock, flags);