serial/nwpserial: Fix wrong register read address and add interrupt acknowledge.

The receive interrupt routine checks the wrong register if the
receive fifo is empty. Further an explicit interrupt acknowledge
write is introduced. In some circumstances another interrupt was
issued.

Signed-off-by: Benjamin Krill <ben@codiert.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/drivers/serial/nwpserial.c b/drivers/serial/nwpserial.c
index 32f3eaf0d262942dd2708c59cfe875fb88e69743..9e150b19d72678d6592a50cb34f6d2da29d899c3 100644 (file)
--- a/drivers/serial/nwpserial.c
+++ b/drivers/serial/nwpserial.c
@@ -145,11 +145,13 @@ static irqreturn_t nwpserial_interrupt(int irq, void *dev_id)
                ch = dcr_read(up->dcr_host, UART_RX);
                if (up->port.ignore_status_mask != NWPSERIAL_STATUS_RXVALID)
                        tty_insert_flip_char(tty, ch, TTY_NORMAL);
-       } while (dcr_read(up->dcr_host, UART_RX) & UART_LSR_DR);
+       } while (dcr_read(up->dcr_host, UART_LSR) & UART_LSR_DR);
 
        tty_flip_buffer_push(tty);
        ret = IRQ_HANDLED;
 
+       /* clear interrupt */
+       dcr_write(up->dcr_host, UART_IIR, 1);
 out:
        spin_unlock(&up->port.lock);
        return ret;