/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    Cortex/CORTEXM_ProcessStack/Src/main.c
  * @author  MCD Application Team
  * @brief   Description of the Cortex-M4 Mode Privilege example.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2020 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define SP_PROCESS_SIZE             0x200  /* Process stack size */
#define SP_PROCESS                  0x02   /* Process stack */
#define SP_MAIN                     0x00   /* Main stack */
/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

/* USER CODE BEGIN PV */
__IO uint8_t PSPMemAlloc[SP_PROCESS_SIZE];
__IO uint32_t Index = 0, PSPValue = 0, CurrentStack = 0, IsrStack = 0xFF, OperationComplete = 0;

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
static __INLINE  void __SVC(void);
/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
#if defined ( __CC_ARM   )
__ASM void __SVC(void)
{
  SVC 0x01
  BX R14
}
#elif defined ( __ICCARM__ )
static __INLINE  void __SVC()
{
  __ASM("svc 0x01");
}
#elif defined   (  __GNUC__  )
static __INLINE void __SVC()
{
  __ASM volatile("svc 0x01");
}
#endif
/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
  /* USER CODE BEGIN 1 */
  /* STM32WLxx HAL library initialization:
       - Configure the Flash prefetch
       - Systick timer is configured by default as source of time base, but user 
         can eventually implement his proper time base source (a general purpose 
         timer for example or other time source), keeping in mind that Time base 
         duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and 
         handled in milliseconds basis.
       - Set NVIC Group Priority to 4
       - Low Level Initialization
     */
  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  /* USER CODE BEGIN 2 */
  BSP_LED_Init(LED2);
  BSP_LED_Off(LED2);

  /* Switch Thread mode Stack from Main to Process -----------------------------*/
  /* Initialize memory reserved for Process Stack */
  for(Index = 0; Index < SP_PROCESS_SIZE; Index++)
  {
    PSPMemAlloc[Index] = 0x00;
  }

  /* Set Process stack value */
  __set_PSP((uint32_t)PSPMemAlloc + SP_PROCESS_SIZE);

  /* Select Process Stack as Thread mode Stack */
  __set_CONTROL(SP_PROCESS);

  /* Execute ISB instruction to flush pipeline as recommended by Arm */
  __ISB();

  /* Get the Thread mode stack used */
  CurrentStack = (__get_CONTROL() & 0x02);

    /* Get process stack pointer value */
    PSPValue = __get_PSP();
  
  /* Check is mode has been well applied */
  if(CurrentStack != SP_PROCESS)
  {
    Error_Handler();
  }

  /* Generate a system call exception: Main Stack pointer should be automaticcaly 
  when entering in ISR context */
  __SVC();

  /* Check is Main stack was used under ISR*/
  if(IsrStack != SP_MAIN)
  {
    Error_Handler();
  }

  /* Get the Thread mode stack used to verify we have switched back automatically 
  to Process Stack */
  
  CurrentStack = (__get_CONTROL() & 0x02);
  
  /* Check is mode has been well applied */
  if(CurrentStack != SP_PROCESS)
  {
    Error_Handler();
  }
  else
  {
    /* Turn LED2 On*/
    OperationComplete = 1;
    BSP_LED_On(LED2);
  }

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */

  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Configure the main internal regulator output voltage
  */
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
  RCC_OscInitStruct.MSIState = RCC_MSI_ON;
  RCC_OscInitStruct.MSICalibrationValue = RCC_MSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_11;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
  /** Configure the SYSCLKSource, HCLK, PCLK1 and PCLK2 clocks dividers
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK3|RCC_CLOCKTYPE_HCLK
                              |RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1
                              |RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.AHBCLK3Divider = RCC_SYSCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  OperationComplete = 2;
  while(1) 
  {
  }
  /* USER CODE END Error_Handler_Debug */
}

#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
    ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  /* Infinite loop */
  while (1)
  {
  }
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
