Fix receive DMA for the console device. Now maybe MAVLink will work better.

nuttx/arch/arm/src/stm32/stm32_serial.c

@@ -1835,6 +1835,13 @@ 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);
+
+  /* If we need to re-initialise the console (e.g. to enable DMA) do that here. */
+
+# if CONFIG_SERIAL_CONSOLE_REINIT
+  uart_devs[CONSOLE_UART - 1]->dev.ops->setup(&uart_devs[CONSOLE_UART - 1]->dev);
+# endif
+
 #endif
 
   /* Register all remaining USARTs */

nuttx/configs/px4fmu/nsh/defconfig

@@ -221,6 +221,9 @@ CONFIG_AT24XX_MTD_BLOCKSIZE=256
 #   tcflush, etc.).  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_CONSOLE_REINIT - re-initializes the console serial port
+#   immediately after creating the /dev/console device.  This is required
+#   if the console serial port has RX DMA enabled.
 #
 # CONFIG_USARTn_SERIAL_CONSOLE - selects the USARTn for the
 #   console and ttys0 (default is the USART1).
@@ -234,6 +237,7 @@ CONFIG_AT24XX_MTD_BLOCKSIZE=256
 # CONFIG_USARTn_2STOP - Two stop bits
 #
 CONFIG_SERIAL_TERMIOS=y
+CONFIG_SERIAL_CONSOLE_REINIT=y
 
 CONFIG_USART1_SERIAL_CONSOLE=y
 CONFIG_USART2_SERIAL_CONSOLE=n
@@ -285,7 +289,7 @@ CONFIG_USART4_2STOP=0
 CONFIG_USART5_2STOP=0
 CONFIG_USART6_2STOP=0
 
-CONFIG_USART1_RXDMA=n
+CONFIG_USART1_RXDMA=y
 CONFIG_USART2_RXDMA=y
 CONFIG_USART3_RXDMA=n
 CONFIG_USART4_RXDMA=n