Added option to disable STM32 serial port re-ordering

ChangeLog

@@ -5350,3 +5350,5 @@
 	* drivers/usbdev/cdcacm.c:  Added FIONREAD and FIONWRITE to CDC/ACM
 	  driver based on serial.c implementation. From Lorenz Meier
 	  (2013-8-10).
+	* arch/arm/src/stm32/Kconfig and stm32_serial.c:  Added option to
+	  disable serial port reordering.  From Lorenz Meier (2013-8-10).

arch/arm/src/stm32/Kconfig

@@ -2473,6 +2473,20 @@ config SERIAL_TERMIOS
 		If this is not defined, then the terminal settings (baud, parity, etc).
 		are not configurable at runtime; serial streams cannot be flushed, etc..
 
+config SERIAL_DISABLE_REORDERING
+	bool "Disable reordering of ttySx devices."
+	depends on STM32_USART1 || STM32_USART2 || STM32_USART3 || STM32_UART4 || STM32_UART5 || STM32_USART6 || STM32_USART7 || STM32_USART8
+	default n
+	---help---
+		NuttX per default reorders the serial ports (/dev/ttySx) so that the
+		console is always on /dev/ttyS0. If more than one UART is in use this
+		can, however, have the side-effect that all port mappings
+		(hardware USART1 -> /dev/ttyS0) change if the console is moved to another
+		UART. This is in particular relevant if a project uses the USB console
+		in some configs and a serial console in other configs, but does not
+		want the side effect of having all serial port names change when just
+		the console is moved from serial to USB.
+
 endmenu
 
 config STM32_USART_SINGLEWIRE

arch/arm/src/stm32/stm32_serial.c

@@ -2417,7 +2417,13 @@ void up_serialinit(void)
 
 #if CONSOLE_UART > 0
   (void)uart_register("/dev/console", &uart_devs[CONSOLE_UART - 1]->dev);
-  (void)uart_register("/dev/ttyS0",   &uart_devs[CONSOLE_UART - 1]->dev);
+
+#ifndef CONFIG_SERIAL_DISABLE_REORDERING
+  /* If not disabled, register the console UART to ttyS0 and exclude
+   * it from initializing it further down
+   */
+
+  (void)uart_register("/dev/ttyS0", &uart_devs[CONSOLE_UART - 1]->dev);
   minor = 1;
 
   /* If we need to re-initialise the console to enable DMA do that here. */
@@ -2425,6 +2431,7 @@ void up_serialinit(void)
 # ifdef SERIAL_HAVE_CONSOLE_DMA
   up_dma_setup(&uart_devs[CONSOLE_UART - 1]->dev);
 # endif
+#endif /* CONFIG_SERIAL_DISABLE_REORDERING not defined */
 
 #endif /* CONSOLE_UART > 0 */
 
@@ -2434,12 +2441,14 @@ void up_serialinit(void)
 
   for (i = 0; i < STM32_NUSART; i++)
     {
+#ifndef CONFIG_SERIAL_DISABLE_REORDERING
       /* Don't create a device for the console - we did that above */
 
       if ((uart_devs[i] == 0) || (uart_devs[i]->dev.isconsole))
         {
           continue;
         }
+#endif
 
       /* Register USARTs as devices in increasing order */