Implement serial receive DMA for the F1xx. This is not quite working right yet. Some clients work, others not so much.

apps/drivers/boards/px4io/px4io_init.c

@@ -95,4 +95,25 @@ __EXPORT void stm32_boardinitialize(void)
 
 	stm32_configgpio(GPIO_ADC_VBATT);
 	stm32_configgpio(GPIO_ADC_IN5);
+
+	/* set up the serial DMA polling */
+#ifdef SERIAL_HAVE_DMA
+	{
+		static struct hrt_call serial_dma_call;
+		struct timespec ts;
+
+		/*
+		 * Poll at 1ms intervals for received bytes that have not triggered
+		 * a DMA event.
+		 */
+		ts.tv_sec = 0;
+		ts.tv_nsec = 1000000;
+
+		hrt_call_every(&serial_dma_call,
+			       ts_to_abstime(&ts),
+			       ts_to_abstime(&ts),
+			       (hrt_callout)stm32_serial_dma_poll,
+			       NULL);
+	}
+#endif
 }

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

@@ -79,8 +79,8 @@
 
 #if SERIAL_HAVE_DMA
 
-/* Verify that DMA has been enabled an the DMA channel has been defined.
+#  if defined(CONFIG_STM32_STM32F20XX) || defined(CONFIG_STM32_STM32F40XX)
- * NOTE:  These assignments may only be true for the F4.
+/* Verify that DMA has been enabled and the DMA channel has been defined.
  */
 
 #    if defined(CONFIG_USART1_RXDMA) || defined(CONFIG_USART6_RXDMA)
@@ -125,6 +125,30 @@
 #      error "USART6 DMA channel not defined (DMAMAP_USART6_RX)"
 #    endif
 
+#  elif defined(CONFIG_STM32_STM32F10XX)
+
+#    if defined(CONFIG_USART1_RXDMA) || defined(CONFIG_USART2_RXDMA) || \
+      defined(CONFIG_USART3_RXDMA)
+#      ifndef CONFIG_STM32_DMA1
+#        error STM32 USART1/2/3 receive DMA requires CONFIG_STM32_DMA1
+#      endif
+#    endif
+
+#    if defined(CONFIG_UART4_RXDMA)
+#      ifndef CONFIG_STM32_DMA2
+#        error STM32 USART4 receive DMA requires CONFIG_STM32_DMA2
+#      endif
+#    endif
+
+/* There are no optional DMA channel assignments for the F1 */
+
+#    define DMAMAP_USART1_RX  DMACHAN_USART1_RX
+#    define DMAMAP_USART2_RX  DMACHAN_USART2_RX
+#    define DMAMAP_USART3_RX  DMACHAN_USART3_RX
+#    define DMAMAP_UART4_RX   DMACHAN_USART4_RX
+
+#  endif
+
 /* The DMA buffer size when using RX DMA to emulate a FIFO.
  *
  * When streaming data, the generic serial layer will be called
@@ -156,6 +180,27 @@
 #    error "Unknown STM32 DMA"
 #  endif
 
+/* DMA control word */
+
+#  if defined(CONFIG_STM32_STM32F20XX) || defined(CONFIG_STM32_STM32F40XX)
+#    define SERIAL_DMA_CONTROL_WORD      \
+                (DMA_SCR_DIR_P2M       | \
+                 DMA_SCR_CIRC          | \
+                 DMA_SCR_MINC          | \
+                 DMA_SCR_PSIZE_8BITS   | \
+                 DMA_SCR_MSIZE_8BITS   | \
+                 CONFIG_USART_DMAPRIO  | \
+                 DMA_SCR_PBURST_SINGLE | \
+                 DMA_SCR_MBURST_SINGLE)
+#  else
+#    define SERIAL_DMA_CONTROL_WORD      \
+                (DMA_CCR_CIRC          | \
+                 DMA_CCR_MINC          | \
+                 DMA_CCR_PSIZE_8BITS   | \
+                 DMA_CCR_MSIZE_8BITS   | \
+                 CONFIG_USART_DMAPRIO)
+# endif
+
 #endif
 
 /* Power management definitions */
@@ -1037,14 +1082,7 @@ static int up_dma_setup(struct uart_dev_s *dev)
                  priv->usartbase + STM32_USART_DR_OFFSET,
                  (uint32_t)priv->rxfifo,
                  RXDMA_BUFFER_SIZE,
-                 DMA_SCR_DIR_P2M       |
+                 SERIAL_DMA_CONTROL_WORD);
-                 DMA_SCR_CIRC          |
-                 DMA_SCR_MINC          |
-                 DMA_SCR_PSIZE_8BITS   |
-                 DMA_SCR_MSIZE_8BITS   |
-                 CONFIG_USART_DMAPRIO  |
-                 DMA_SCR_PBURST_SINGLE |
-                 DMA_SCR_MBURST_SINGLE);
 
   /* Reset our DMA shadow pointer to match the address just
    * programmed above.

nuttx/arch/arm/src/stm32/stm32_uart.h

@@ -145,7 +145,7 @@
  * extended to the F1 and F2 with a little effort in the DMA code.
  */
 
-#if !defined(HAVE_UART) || !defined(CONFIG_ARCH_DMA) || !defined(CONFIG_STM32_STM32F40XX)
+#if !defined(HAVE_UART) || !defined(CONFIG_ARCH_DMA)
 #  undef CONFIG_USART1_RXDMA
 #  undef CONFIG_USART2_RXDMA
 #  undef CONFIG_USART3_RXDMA

nuttx/configs/px4io/io/defconfig

@@ -188,6 +188,11 @@ CONFIG_USART1_2STOP=0
 CONFIG_USART2_2STOP=0
 CONFIG_USART3_2STOP=0
 
+CONFIG_USART1_RXDMA=y
+SERIAL_HAVE_CONSOLE_DMA=y
+CONFIG_USART2_RXDMA=y
+CONFIG_USART3_RXDMA=y
+
 #
 # PX4IO specific driver settings
 #