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>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 147c9e193595..72bc1dbcd055 100644
--- 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;
 }