fix: improve boot fault visibility and defer watchdog start

Core/Src/debug_log.c

@@ -75,6 +75,19 @@ void debug_log_fault(const char *tag)
     debug_log_printf("[FAULT] %s\r\n", (tag != NULL) ? tag : "(null)");
 }
 
+void debug_log_fault_context(const char *tag, const char *file, int line)
+{
+    debug_log_printf("[FAULT] %s file=%s line=%d free=%lu min=%lu seq=%lu drop=%lu last_drop=%lu\r\n",
+                     (tag != NULL) ? tag : "(null)",
+                     (file != NULL) ? file : "(null)",
+                     line,
+                     (unsigned long)xPortGetFreeHeapSize(),
+                     (unsigned long)xPortGetMinimumEverFreeHeapSize(),
+                     (unsigned long)g_rtt_log_seq,
+                     (unsigned long)g_rtt_log_drop_count,
+                     (unsigned long)g_rtt_log_last_drop_seq);
+}
+
 void debug_log_runtime_snapshot(void)
 {
     UBaseType_t default_hwm;

Core/Src/freertos.c

@@ -89,13 +89,23 @@ static void StartDefaultTask(void *argument)
 {
     TickType_t last_snapshot = xTaskGetTickCount();
     BaseType_t alive_logged = pdFALSE;
+    BaseType_t iwdg_ready = pdFALSE;
 
     (void)argument;
     debug_log_boot("default-task");
 
+    if (MX_IWDG_Init() == HAL_OK) {
+        debug_log_write("[BOOT] iwdg-started\r\n");
+        iwdg_ready = pdTRUE;
+    } else {
+        debug_log_write("[BOOT] iwdg-init-fail\r\n");
+    }
+
     for (;;) {
         HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);
-        HAL_IWDG_Refresh(&hiwdg);
+        if (iwdg_ready == pdTRUE) {
+            HAL_IWDG_Refresh(&hiwdg);
+        }
         if (alive_logged == pdFALSE) {
             debug_log_write("[RTOS] alive\r\n");
             alive_logged = pdTRUE;

Core/Src/iwdg.c

@@ -27,7 +27,7 @@
 IWDG_HandleTypeDef hiwdg;
 
 /* IWDG init function */
-void MX_IWDG_Init(void)
+HAL_StatusTypeDef MX_IWDG_Init(void)
 {
 
   /* USER CODE BEGIN IWDG_Init 0 */
@@ -42,12 +42,12 @@ void MX_IWDG_Init(void)
   hiwdg.Init.Reload = 4095;
   if (HAL_IWDG_Init(&hiwdg) != HAL_OK)
   {
-    Error_Handler();
+    return HAL_ERROR;
   }
   /* USER CODE BEGIN IWDG_Init 2 */
 
   /* USER CODE END IWDG_Init 2 */
-
+  return HAL_OK;
 }
 
 /* USER CODE BEGIN 1 */

Core/Src/main.c

@@ -142,7 +142,6 @@ int main(void)
   /* Initialize all configured peripherals */
   MX_GPIO_Init();
   MX_DMA_Init();
-  MX_IWDG_Init();
   MX_USART1_UART_Init();
   MX_USART2_UART_Init();
   MX_USART3_UART_Init();
@@ -231,7 +230,28 @@ void SystemClock_Config(void)
  */
 void Debug_TrapWithRttHint(const char *tag)
 {
-  debug_log_fault(tag);
+  debug_log_fault_context(tag, __FILE__, __LINE__);
+}
+
+void vApplicationMallocFailedHook(void)
+{
+  debug_log_fault_context("malloc-failed", __FILE__, __LINE__);
+  __disable_irq();
+  for (;;)
+  {
+  }
+}
+
+void vApplicationStackOverflowHook(TaskHandle_t xTask, char *pcTaskName)
+{
+  debug_log_printf("[FAULT] stack-overflow task=%s\r\n",
+                   (pcTaskName != NULL) ? pcTaskName : "(null)");
+  debug_log_fault_context("stack-overflow", __FILE__, __LINE__);
+  (void)xTask;
+  __disable_irq();
+  for (;;)
+  {
+  }
 }
 
 /* USER CODE END 4 */
@@ -244,7 +264,7 @@ void Error_Handler(void)
 {
   /* USER CODE BEGIN Error_Handler_Debug */
   /* User can add his own implementation to report the HAL error return state */
-  debug_log_fault("error-handler");
+  debug_log_fault_context("error-handler", __FILE__, __LINE__);
   __disable_irq();
   while (1)
   {