[bootloader/uart_driver] Adding uart watchdog to recover uart it receive

This commit is about adding uart watchdog. The TIM1 is used to clear the
uart periodically, when the uart is inactive. It might be the case that
some bytes are received (less than 256). If that happens, uart will
still wait for the rest of the bytes until it receives 256, in order to
parse them. This can create a permanent issue in uart communication.

After a period of inactivity, uart is reinitialized to expect again 256
bytes.

Signed-off-by: George Pappas <pappasgeorge12@gmail.com>

Author: gpappasv

projects/bootloader/boards/stm32f401re/Src/stm32f4xx_it.c

@@ -22,6 +22,8 @@
 #include "uart_driver.h"
 #include "stm32f4xx_hal.h"
 #include "stm32f4xx_it.h"
+#include "stm32f401xe.h"
+#include <stdio.h>
 
 /* External variables --------------------------------------------------------*/
 extern UART_HandleTypeDef huart2;
@@ -128,4 +130,15 @@ void
 USART2_IRQHandler(void)
 {
     HAL_UART_IRQHandler(&huart2);
+    uart_driver_feed_wdg();
 }
+
+void
+TIM1_UP_TIM10_IRQHandler(void)
+{
+    if (TIM1->SR & TIM_SR_UIF) // If update interrupt flag is set
+    {
+        TIM1->SR &= ~TIM_SR_UIF; // Clear the interrupt flag
+        uart_driver_rx_recover();
+    }
+}

projects/bootloader/src/drivers/uart/uart_driver.c

@@ -14,8 +14,12 @@
 #include <stdio.h>
 #include <stdint.h>
 #include "stm32f4xx_hal.h"
+#include "stm32f401xe.h" // stm32f401re
 #include "sys_init.h"
 
+// --- defines ---------------------------------------------------------------------------------------------------------
+#define TIM1_COUNTDOWN_SEC 15 // 15 seconds timeout for the uart reception watchdog
+
 // --- static variable definitions -------------------------------------------------------------------------------------
 // This is the structure that will store the received buffer and the size of it. This will be used by the upper layers
 // to receive the data.
@@ -27,9 +31,43 @@ static process_rx_data data_rx_cb = NULL;
 UART_HandleTypeDef huart2;
 
 // --- static function declarations ------------------------------------------------------------------------------------
+static void uart_recv_it_init_wdg(void);
 static void MX_USART2_UART_Init(void);
 
 // --- static function definitions -------------------------------------------------------------------------------------
+/**
+ * @brief This function initializes the timer1 peripheral to be used as a watchdog for the uart reception.
+ *        TODO: GPA: We can set the timer to one-pulse mode, so that it will stop after the timeout. The timer can be
+ * re-enabled by the uart isr, only when needed.
+ *
+ */
+static void
+uart_recv_it_init_wdg(void)
+{
+    // Enable the TIM1 clock
+    RCC->APB2ENR |= RCC_APB2ENR_TIM1EN;
+
+    TIM1->SMCR = 0;
+    TIM1->DIER = TIM_DIER_UIE; // Enable update interrupt
+    TIM1->SR   = 0;            // Clear status register
+    TIM1->EGR  = TIM_EGR_UG;   // Generate an update event to reload the prescaler
+    // Configure the prescaler such is to generate 1ms ticks. The systemclock is 84mhz
+    TIM1->PSC = 21000 - 1; // this means 1ms -> 4000 ticks
+
+    // Set the auto-reload value for a 15-second countdown
+    TIM1->ARR = TIM1_COUNTDOWN_SEC * 4000 - 1;
+    TIM1->CNT = TIM1->ARR; // Set the counter to the auto-reload value
+    TIM1->CR2 = 0;
+    // CR1 config: URS = 1, DIR = 1, CEN = 1
+    TIM1->CR1 = (TIM_CR1_URS | TIM_CR1_DIR | TIM_CR1_CEN);
+
+    // Clear any pending update interrupt flags
+    TIM1->SR &= ~TIM_SR_UIF;
+    // Enable the update interrupt for TIM1 in NVIC
+    NVIC_SetPriority(TIM1_UP_TIM10_IRQn, 0); // Set interrupt priority
+    NVIC_EnableIRQ(TIM1_UP_TIM10_IRQn);
+}
+
 /**
  * @brief USART2 Initialization Function
  * @param None
@@ -68,6 +106,8 @@ MX_USART2_UART_Init(void) // Change from MX_USART1_UART_Init to MX_USART2_UART_I
 #endif
     }
     HAL_UART_Receive_IT(&huart2, uart_buf.data_buffer, uart_buf.len); // Start reception
+    // Init the uart watchdog
+    uart_recv_it_init_wdg();
 }
 
 // --- function definitions --------------------------------------------------------------------------------------------
@@ -124,7 +164,8 @@ HAL_UART_ErrorCallback(UART_HandleTypeDef *huart)
 {
     if (huart->Instance == USART2)
     {
-        // TODO: GPA: Handle the possible errors and restart the reception
+        HAL_UART_DeInit(&huart2);
+        HAL_UART_Init(&huart2);
         HAL_UART_Receive_IT(&huart2, uart_buf.data_buffer, uart_buf.len);
     }
 }
@@ -139,6 +180,31 @@ uart_driver_init(void)
     MX_USART2_UART_Init();
 }
 
+/**
+ * @brief Function to feed the uart watchdog. Will be called by the uart isr, every time something is being received.
+ *
+ */
+void
+uart_driver_feed_wdg(void)
+{
+    // Reset the uart wdg timer to not trigger the buffer reset.
+    TIM1->CNT = TIM1->ARR;
+}
+
+/**
+ * @brief Function to recover the uart reception.
+ *
+ */
+void
+uart_driver_rx_recover(void)
+{
+    HAL_UART_DeInit(&huart2);
+    HAL_UART_Init(&huart2);
+    // Restart the reception
+    HAL_UART_Receive_IT(&huart2, uart_buf.data_buffer, uart_buf.len);
+    printf("Recovering uart reception\r\n");
+}
+
 /**
  * @brief Function to register an rx callback function. This will be used by the com_protocol to register a callback
  *        function and process the received message.

projects/bootloader/src/drivers/uart/uart_driver.h

@@ -14,7 +14,7 @@
 // --- defines ---------------------------------------------------------------------------------------------------------
 #define USART_TX_Pin        GPIO_PIN_2
 #define USART_RX_Pin        GPIO_PIN_3
-#define RX_CHUNK_SIZE_BYTES 256
+#define RX_CHUNK_SIZE_BYTES 256 // TODO: GPA: Right now, we need to send a buffer of 256 bytes, even if the effective payload is smaller.
 
 // --- structs ---------------------------------------------------------------------------------------------------------
 struct uart_driver_data_s
@@ -28,5 +28,7 @@ typedef void (*process_rx_data)(struct uart_driver_data_s * const rx_data);
 
 // --- function declarations -------------------------------------------------------------------------------------------
 void uart_driver_init(void);
+void uart_driver_feed_wdg(void);
+void uart_driver_rx_recover(void);
 void uart_driver_register_rx_callback(process_rx_data rx_cb);
 void uart_tx_data(uint8_t *buffer, uint16_t length);

scripts/firmware_update_tools/bootloader_tool.py

@@ -157,7 +157,10 @@ def perform_firmware_update(self):
         print("FWUG_START Message:", start_msg)
         response = send_message_via_serial(start_msg, self.com_port, self.baud_rate, 5, 10)
         if not self.parse_fwug_response(response, packet_number):
-            print("Firmware update failed. Exiting...")
+            # If firmware update start failed, send a cancel message and return
+            cancel_msg = self.create_fwug_cancel_msg()
+            send_message_via_serial(cancel_msg, self.com_port, self.baud_rate)
+            print("Firmware update failed. Attempting to cancel... (and exiting)")
             return
         else:
             packet_number += 1