serial/mxs-auart: fix race condition in interrupt handler

[~andy/linux] / drivers / tty / serial / mxs-auart.c

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 4f5f161896a139852e46f93f30239be979838bda..3de0fb2712f596ff0b1b768375e4fd2acf3a1b28 100644 (file)
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -678,11 +678,18 @@ static void mxs_auart_settermios(struct uart_port *u,
 
 static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
 {
-       u32 istatus, istat;
+       u32 istat;
        struct mxs_auart_port *s = context;
        u32 stat = readl(s->port.membase + AUART_STAT);
 
-       istatus = istat = readl(s->port.membase + AUART_INTR);
+       istat = readl(s->port.membase + AUART_INTR);
+
+       /* ack irq */
+       writel(istat & (AUART_INTR_RTIS
+               | AUART_INTR_TXIS
+               | AUART_INTR_RXIS
+               | AUART_INTR_CTSMIS),
+                       s->port.membase + AUART_INTR_CLR);
 
        if (istat & AUART_INTR_CTSMIS) {
                uart_handle_cts_change(&s->port, stat & AUART_STAT_CTS);
@@ -702,12 +709,6 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
                istat &= ~AUART_INTR_TXIS;
        }
 
-       writel(istatus & (AUART_INTR_RTIS
-               | AUART_INTR_TXIS
-               | AUART_INTR_RXIS
-               | AUART_INTR_CTSMIS),
-                       s->port.membase + AUART_INTR_CLR);
-
        return IRQ_HANDLED;
 }