Use DMA for UART RX instead of interrupts.

DMA is more efficient and less prone to miss characters than interrupts.

An open question is if circular mode is really the best. If someone
copy-pastes more than the RX buffer size of configuration into the CLI,
we risk the DMA controller catching up with the reader and overwriting
data not yet read.

Since we don't have flow control back to the users terminal, we will
always fail if too much data is entered before we can process it. The
question is if failing to stuff new data at the end of a buffer might be
better than data being overwritten - thus messing up the commands in
unpredictable ways.

2 files changed, 73 insertions, 3 deletions

diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_msp.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_msp.c
index 2a207b6..91a6f46 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_msp.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_hal_msp.c
@@ -33,10 +33,8 @@
 */
 /* Includes ------------------------------------------------------------------*/
 #include "stm32f4xx_hal.h"
+#include "stm-uart.h"
 
-/* USER CODE BEGIN 0 */
-
-/* USER CODE END 0 */
 
 /**
  * Initializes the Global MSP.
@@ -121,6 +119,8 @@ void HAL_UART_MspInit(UART_HandleTypeDef* huart)
   GPIO_InitTypeDef GPIO_InitStruct;
 
   if (huart->Instance == USART1) {
+    /* This is huart_mgmt (USER_MGMT) */
+
     /* Peripheral clock enable */
     __USART1_CLK_ENABLE();
     __GPIOA_CLK_ENABLE();
@@ -138,7 +138,32 @@ void HAL_UART_MspInit(UART_HandleTypeDef* huart)
 
     HAL_NVIC_SetPriority(USART1_IRQn, 0, 1);
     HAL_NVIC_EnableIRQ(USART1_IRQn);
+
+    /* Peripheral DMA init*/
+    hdma_usart_mgmt_rx.Instance = DMA2_Stream2;
+    hdma_usart_mgmt_rx.Init.Channel = DMA_CHANNEL_4;
+    hdma_usart_mgmt_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
+    hdma_usart_mgmt_rx.Init.PeriphInc = DMA_PINC_DISABLE;
+    hdma_usart_mgmt_rx.Init.MemInc = DMA_MINC_ENABLE;
+    hdma_usart_mgmt_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
+    hdma_usart_mgmt_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
+    hdma_usart_mgmt_rx.Init.Mode = DMA_CIRCULAR;
+    hdma_usart_mgmt_rx.Init.Priority = DMA_PRIORITY_LOW;
+    hdma_usart_mgmt_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
+    /*
+    hdma_usart_mgmt_rx.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_HALFFULL;
+    hdma_usart_mgmt_rx.Init.MemBurst = DMA_MBURST_SINGLE;
+    hdma_usart_mgmt_rx.Init.PeriphBurst = DMA_PBURST_SINGLE;
+    */
+    if (HAL_DMA_Init(&hdma_usart_mgmt_rx) != HAL_OK) {
+	Error_Handler();
+    }
+
+    __HAL_LINKDMA(huart, hdmarx, hdma_usart_mgmt_rx);
+
   } else if (huart->Instance == USART2) {
+    /* This is huart_user (USER UART) */
+
     /* Peripheral clock enable */
     __USART2_CLK_ENABLE();
     __GPIOA_CLK_ENABLE();
@@ -156,6 +181,28 @@ void HAL_UART_MspInit(UART_HandleTypeDef* huart)
 
     HAL_NVIC_SetPriority(USART2_IRQn, 0, 1);
     HAL_NVIC_EnableIRQ(USART2_IRQn);
+
+    /* Peripheral DMA init*/
+    hdma_usart_user_rx.Instance = DMA1_Stream5;
+    hdma_usart_user_rx.Init.Channel = DMA_CHANNEL_4;
+    hdma_usart_user_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
+    hdma_usart_user_rx.Init.PeriphInc = DMA_PINC_DISABLE;
+    hdma_usart_user_rx.Init.MemInc = DMA_MINC_ENABLE;
+    hdma_usart_user_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
+    hdma_usart_user_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
+    hdma_usart_user_rx.Init.Mode = DMA_CIRCULAR;
+    hdma_usart_user_rx.Init.Priority = DMA_PRIORITY_LOW;
+    hdma_usart_user_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
+    /*
+    hdma_usart_user_rx.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_HALFFULL;
+    hdma_usart_user_rx.Init.MemBurst = DMA_MBURST_SINGLE;
+    hdma_usart_user_rx.Init.PeriphBurst = DMA_PBURST_SINGLE;
+    */
+    if (HAL_DMA_Init(&hdma_usart_user_rx) != HAL_OK) {
+	Error_Handler();
+    }
+
+    __HAL_LINKDMA(huart, hdmarx, hdma_usart_user_rx);
   }
 }
 
@@ -172,6 +219,9 @@ void HAL_UART_MspDeInit(UART_HandleTypeDef* huart)
     HAL_GPIO_DeInit(GPIOA, GPIO_PIN_2 | GPIO_PIN_3);
 
     HAL_NVIC_DisableIRQ(USART1_IRQn);
+
+    /* Peripheral DMA DeInit*/
+    HAL_DMA_DeInit(huart->hdmarx);
   } else if (huart->Instance == USART2) {
     /* Peripheral clock disable */
     __USART2_CLK_DISABLE();
@@ -183,6 +233,9 @@ void HAL_UART_MspDeInit(UART_HandleTypeDef* huart)
     HAL_GPIO_DeInit(GPIOA, GPIO_PIN_9 | GPIO_PIN_10);
 
     HAL_NVIC_DisableIRQ(USART2_IRQn);
+
+    /* Peripheral DMA DeInit*/
+    HAL_DMA_DeInit(huart->hdmarx);
   }
 }
 
diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_it.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_it.c
index a174d73..b3de408 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_it.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/stm32f4xx_it.c
@@ -166,4 +166,21 @@ void USART2_IRQHandler(void)
     HAL_UART_IRQHandler(&huart_user);
 }
 
+/**
+* @brief This function handles DMA1 stream5 global interrupt.
+*/
+void DMA1_Stream5_IRQHandler(void)
+{
+    HAL_DMA_IRQHandler(&hdma_usart_user_rx);
+}
+
+/**
+* @brief This function handles DMA2 stream2 global interrupt.
+*/
+void DMA2_Stream2_IRQHandler(void)
+{
+    HAL_DMA_IRQHandler(&hdma_usart_mgmt_rx);
+}
+
+
 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/