serial: imx: Add Rx Fifo overrun error message

This patch enables the overrun error (ORE) interrupt and increases the
counter in case of overrun.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 147c9e1935951dcca13a7df60b2d02e999663a30..72bc1dbcd055bba2f2c50c83f891584c36a747c7 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -449,6 +449,13 @@ 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);
 
        temp = readl(sport->port.membase + UCR1);
        writel(temp | UCR1_TXMPTYEN, sport->port.membase + UCR1);
@@ -582,6 +589,7 @@ static irqreturn_t imx_int(int irq, void *dev_id)
 {
        struct imx_port *sport = dev_id;
        unsigned int sts;
+       unsigned int sts2;
 
        sts = readl(sport->port.membase + USR1);
 
@@ -598,6 +606,13 @@ static irqreturn_t imx_int(int irq, void *dev_id)
        if (sts & USR1_AWAKE)
                writel(USR1_AWAKE, sport->port.membase + USR1);
 
+       sts2 = readl(sport->port.membase + USR2);
+       if (sts2 & USR2_ORE) {
+               dev_err(sport->port.dev, "Rx FIFO overrun\n");
+               sport->port.icount.overrun++;
+               writel(sts2 | USR2_ORE, sport->port.membase + USR2);
+       }
+
        return IRQ_HANDLED;
 }