serial: imx: add CREAD flag support

Add CREAD flag hanlding in set_termios and UART DMA mode
which ignores all received chars when CREAD flag cleared.

Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Anton Bondarenko <anton_bondarenko@mentor.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 4c5e909..eb2210f 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -74,6 +74,7 @@
 #define IMX21_UTS 0xb4 /* UART Test Register on all other i.mx*/
 
 /* UART Control Register Bit Fields.*/
+#define URXD_DUMMY_READ (1<<16)
 #define URXD_CHARRDY   (1<<15)
 #define URXD_ERR       (1<<14)
 #define URXD_OVRRUN    (1<<13)
@@ -710,6 +711,9 @@ static irqreturn_t imx_rxint(int irq, void *dev_id)
 #endif
                }
 
+               if (sport->port.ignore_status_mask & URXD_DUMMY_READ)
+                       goto out;
+
                tty_insert_flip_char(port, rx, flg);
        }
 
@@ -910,7 +914,8 @@ static void dma_rx_callback(void *data)
        dev_dbg(sport->port.dev, "We get %d bytes.\n", count);
 
        if (count) {
-               tty_insert_flip_string(port, sport->rx_buf, count);
+               if (!(sport->port.ignore_status_mask & URXD_DUMMY_READ))
+                       tty_insert_flip_string(port, sport->rx_buf, count);
                tty_flip_buffer_push(port);
 
                start_rx_dma(sport);
@@ -1330,6 +1335,9 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
                        sport->port.ignore_status_mask |= URXD_OVRRUN;
        }
 
+       if ((termios->c_cflag & CREAD) == 0)
+               sport->port.ignore_status_mask |= URXD_DUMMY_READ;
+
        /*
         * Update the per-port timeout.
         */