ENGR00322379 tty: serial: imx: set uart to cpu mode by default

Now uart cannot work well with CSR/Atheros BT module with SDMA
mode. Set it to cpu mode before SDMA mode work.

To enable dma mode, just add "fsl,dma-mode" in the device tree for
the node.

Signed-off-by: Fugang Duan <B38611@freescale.com>

2 files changed, 7 insertions, 1 deletions

diff --git a/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt b/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
index c662eb36be29..17fd9bc716ec 100644
--- a/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
+++ b/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
@@ -10,6 +10,8 @@ Optional properties:
 - fsl,irda-mode : Indicate the uart supports irda mode
 - fsl,dte-mode : Indicate the uart works in DTE mode. The uart works
                   is DCE mode by default.
+- fsl,dma-mode : Indicate the uart works in dma mode. The uart works
+                  is cpu mode by default.
 
 Example:
 
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index a8f2215dffbc..5ecaee07cbac 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -208,6 +208,7 @@ struct imx_port {
         unsigned int            have_rtscts:1;
         unsigned int            dte_mode:1;
         unsigned int            use_irda:1;
+        unsigned int            dma_mode:1;
         unsigned int            irda_inv_rx:1;
         unsigned int            irda_inv_tx:1;
         unsigned short          trcv_delay; /* transceiver delay */
@@ -1357,7 +1358,7 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
 
                         /* Can we enable the DMA support? */
                         if (is_imx6q_uart(sport) && !uart_console(port)
-                                && !sport->dma_is_inited)
+                                && !sport->dma_is_inited && sport->dma_mode)
                                 imx_uart_dma_init(sport);
                 } else {
                         termios->c_cflag &= ~CRTSCTS;
@@ -1920,6 +1921,9 @@ static int serial_imx_probe_dt(struct imx_port *sport,
         if (of_get_property(np, "fsl,dte-mode", NULL))
                 sport->dte_mode = 1;
 
+        if (of_get_property(np, "fsl,dma-mode", NULL))
+                sport->dma_mode = 1;
+
         sport->devdata = of_id->data;
 
         return 0;