serial: at91: support run time switch transfer mode

We will switch to pio mode when request of dma or pdc fail.
But soon or later, when the request is success, the transfer mode can switch to them at
next open serial port action.
So in startup stage, we should get original transfer mode.
Signed-off-by: NElen Song <elen.song@atmel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/atmel_serial.c

@@ -1370,6 +1370,80 @@ static void atmel_tasklet_func(unsigned long data)
 	spin_unlock(&port->lock);
 }
 
+static int atmel_init_property(struct atmel_uart_port *atmel_port,
+				struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct atmel_uart_data *pdata = pdev->dev.platform_data;
+
+	if (np) {
+		/* DMA/PDC usage specification */
+		if (of_get_property(np, "atmel,use-dma-rx", NULL)) {
+			if (of_get_property(np, "dmas", NULL)) {
+				atmel_port->use_dma_rx  = true;
+				atmel_port->use_pdc_rx  = false;
+			} else {
+				atmel_port->use_dma_rx  = false;
+				atmel_port->use_pdc_rx  = true;
+			}
+		} else {
+			atmel_port->use_dma_rx  = false;
+			atmel_port->use_pdc_rx  = false;
+		}
+
+		if (of_get_property(np, "atmel,use-dma-tx", NULL)) {
+			if (of_get_property(np, "dmas", NULL)) {
+				atmel_port->use_dma_tx  = true;
+				atmel_port->use_pdc_tx  = false;
+			} else {
+				atmel_port->use_dma_tx  = false;
+				atmel_port->use_pdc_tx  = true;
+			}
+		} else {
+			atmel_port->use_dma_tx  = false;
+			atmel_port->use_pdc_tx  = false;
+		}
+
+	} else {
+		atmel_port->use_pdc_rx  = pdata->use_dma_rx;
+		atmel_port->use_pdc_tx  = pdata->use_dma_tx;
+		atmel_port->use_dma_rx  = false;
+		atmel_port->use_dma_tx  = false;
+	}
+
+	return 0;
+}
+
+static void atmel_init_rs485(struct atmel_uart_port *atmel_port,
+				struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct atmel_uart_data *pdata = pdev->dev.platform_data;
+
+	if (np) {
+		u32 rs485_delay[2];
+		/* rs485 properties */
+		if (of_property_read_u32_array(np, "rs485-rts-delay",
+					rs485_delay, 2) == 0) {
+			struct serial_rs485 *rs485conf = &atmel_port->rs485;
+
+			rs485conf->delay_rts_before_send = rs485_delay[0];
+			rs485conf->delay_rts_after_send = rs485_delay[1];
+			rs485conf->flags = 0;
+
+		if (of_get_property(np, "rs485-rx-during-tx", NULL))
+			rs485conf->flags |= SER_RS485_RX_DURING_TX;
+
+		if (of_get_property(np, "linux,rs485-enabled-at-boot-time",
+								NULL))
+			rs485conf->flags |= SER_RS485_ENABLED;
+		}
+	} else {
+		atmel_port->rs485       = pdata->rs485;
+	}
+
+}
+
 static void atmel_set_ops(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
@@ -1408,6 +1482,7 @@ static void atmel_set_ops(struct uart_port *port)
  */
 static int atmel_startup(struct uart_port *port)
 {
+	struct platform_device *pdev = to_platform_device(port->dev);
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 	struct tty_struct *tty = port->state->port.tty;
 	int retval;
@@ -1432,6 +1507,8 @@ static int atmel_startup(struct uart_port *port)
 	/*
 	 * Initialize DMA (if necessary)
 	 */
+	atmel_init_property(atmel_port, pdev);
+
 	if (atmel_port->prepare_rx) {
 		retval = atmel_port->prepare_rx(port);
 		if (retval < 0)
@@ -1877,55 +1954,6 @@ static struct uart_ops atmel_pops = {
 #endif
 };
 
-static void atmel_of_init_port(struct atmel_uart_port *atmel_port,
-					 struct device_node *np)
-{
-	u32 rs485_delay[2];
-
-	/* DMA/PDC usage specification */
-	if (of_get_property(np, "atmel,use-dma-rx", NULL)) {
-		if (of_get_property(np, "dmas", NULL)) {
-			atmel_port->use_dma_rx	= true;
-			atmel_port->use_pdc_rx	= false;
-		} else {
-			atmel_port->use_dma_rx	= false;
-			atmel_port->use_pdc_rx	= true;
-		}
-	} else {
-		atmel_port->use_dma_rx	= false;
-		atmel_port->use_pdc_rx	= false;
-	}
-
-	if (of_get_property(np, "atmel,use-dma-tx", NULL)) {
-		if (of_get_property(np, "dmas", NULL)) {
-			atmel_port->use_dma_tx	= true;
-			atmel_port->use_pdc_tx	= false;
-		} else {
-			atmel_port->use_dma_tx	= false;
-			atmel_port->use_pdc_tx	= true;
-		}
-	} else {
-		atmel_port->use_dma_tx	= false;
-		atmel_port->use_pdc_tx	= false;
-	}
-
-	/* rs485 properties */
-	if (of_property_read_u32_array(np, "rs485-rts-delay",
-					    rs485_delay, 2) == 0) {
-		struct serial_rs485 *rs485conf = &atmel_port->rs485;
-
-		rs485conf->delay_rts_before_send = rs485_delay[0];
-		rs485conf->delay_rts_after_send = rs485_delay[1];
-		rs485conf->flags = 0;
-
-		if (of_get_property(np, "rs485-rx-during-tx", NULL))
-			rs485conf->flags |= SER_RS485_RX_DURING_TX;
-
-		if (of_get_property(np, "linux,rs485-enabled-at-boot-time", NULL))
-			rs485conf->flags |= SER_RS485_ENABLED;
-	}
-}
-
 /*
  * Configure the port from the platform device resource info.
  */
@@ -1936,17 +1964,10 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
 	struct uart_port *port = &atmel_port->uart;
 	struct atmel_uart_data *pdata = pdev->dev.platform_data;
 
-	if (pdev->dev.of_node) {
-		atmel_of_init_port(atmel_port, pdev->dev.of_node);
-	} else {
-		atmel_port->use_pdc_rx	= pdata->use_dma_rx;
-		atmel_port->use_pdc_tx	= pdata->use_dma_tx;
-		atmel_port->use_dma_rx	= false;
-		atmel_port->use_dma_tx	= false;
-		atmel_port->rs485	= pdata->rs485;
-	}
+	if (!atmel_init_property(atmel_port, pdev))
+		atmel_set_ops(port);
 
-	atmel_set_ops(port);
+	atmel_init_rs485(atmel_port, pdev);
 
 	port->iotype		= UPIO_MEM;
 	port->flags		= UPF_BOOT_AUTOCONF;