text: /**
    ******************************************************************************
    * @file    stm32f7xx_hal_crc.c
    * @author  MCD Application Team
    * @brief   CRC HAL module driver.
    *          This file provides firmware functions to manage the following
    *          functionalities of the Cyclic Redundancy Check (CRC) peripheral:
    *           + Initialization and de-initialization functions
    *           + Peripheral Control functions
    *           + Peripheral State functions
    *
    @verbatim
   ===============================================================================
                       ##### How to use this driver #####
   ===============================================================================
      [..]
           (+) Enable CRC AHB clock using __HAL_RCC_CRC_CLK_ENABLE();
           (+) Initialize CRC calculator
               (++) specify generating polynomial (peripheral default or non-default one)
               (++) specify initialization value (peripheral default or non-default one)
               (++) specify input data format
               (++) specify input or output data inversion mode if any
           (+) Use HAL_CRC_Accumulate() function to compute the CRC value of the
               input data buffer starting with the previously computed CRC as
               initialization value
           (+) Use HAL_CRC_Calculate() function to compute the CRC value of the
               input data buffer starting with the defined initialization value
               (default or non-default) to initiate CRC calculation
  
    @endverbatim
    ******************************************************************************
    * @attention
    *
    * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics.
    * All rights reserved.</center></h2>
    *
    * This software component is licensed by ST under BSD 3-Clause license,
    * the "License"; You may not use this file except in compliance with the
    * License. You may obtain a copy of the License at:
    *                        opensource.org/licenses/BSD-3-Clause
    *
    ******************************************************************************
    */
  
  /* Includes ------------------------------------------------------------------*/
  #include "stm32f7xx_hal.h"
  
  /** @addtogroup STM32F7xx_HAL_Driver
    * @{
    */
  
  /** @defgroup CRC CRC
    * @brief CRC HAL module driver.
    * @{
    */
  
  #ifdef HAL_CRC_MODULE_ENABLED
  
  /* Private typedef -----------------------------------------------------------*/
  /* Private define ------------------------------------------------------------*/
  /* Private macro -------------------------------------------------------------*/
  /* Private variables ---------------------------------------------------------*/
  /* Private function prototypes -----------------------------------------------*/
  /** @defgroup CRC_Private_Functions CRC Private Functions
   * @{
   */
  static uint32_t CRC_Handle_8(CRC_HandleTypeDef *hcrc, uint8_t pBuffer[], uint32_t BufferLength);
  static uint32_t CRC_Handle_16(CRC_HandleTypeDef *hcrc, uint16_t pBuffer[], uint32_t BufferLength);
  /**
    * @}
    */
  
  /* Exported functions --------------------------------------------------------*/
  
  /** @defgroup CRC_Exported_Functions CRC Exported Functions
    * @{
    */
  
  /** @defgroup CRC_Exported_Functions_Group1 Initialization and de-initialization functions
   *  @brief    Initialization and Configuration functions.
   *
  @verbatim
   ===============================================================================
              ##### Initialization and de-initialization functions #####
   ===============================================================================
      [..]  This section provides functions allowing to:
        (+) Initialize the CRC according to the specified parameters
            in the CRC_InitTypeDef and create the associated handle
        (+) DeInitialize the CRC peripheral
        (+) Initialize the CRC MSP (MCU Specific Package)
        (+) DeInitialize the CRC MSP
  
  @endverbatim
    * @{
    */
  
  /**
    * @brief  Initialize the CRC according to the specified
    *         parameters in the CRC_InitTypeDef and create the associated handle.
    * @param  hcrc CRC handle
    * @retval HAL status
    */
  HAL_StatusTypeDef HAL_CRC_Init(CRC_HandleTypeDef *hcrc)
  {
    /* Check the CRC handle allocation */
    if (hcrc == NULL)
    {
      return HAL_ERROR;
    }
  
    /* Check the parameters */
    assert_param(IS_CRC_ALL_INSTANCE(hcrc->Instance));
  
    if (hcrc->State == HAL_CRC_STATE_RESET)
    {
      /* Allocate lock resource and initialize it */
      hcrc->Lock = HAL_UNLOCKED;
      /* Init the low level hardware */
      HAL_CRC_MspInit(hcrc);
    }
  
    hcrc->State = HAL_CRC_STATE_BUSY;
  
    /* check whether or not non-default generating polynomial has been
     * picked up by user */
    assert_param(IS_DEFAULT_POLYNOMIAL(hcrc->Init.DefaultPolynomialUse));
    if (hcrc->Init.DefaultPolynomialUse == DEFAULT_POLYNOMIAL_ENABLE)
    {
      /* initialize peripheral with default generating polynomial */
      WRITE_REG(hcrc->Instance->POL, DEFAULT_CRC32_POLY);
      MODIFY_REG(hcrc->Instance->CR, CRC_CR_POLYSIZE, CRC_POLYLENGTH_32B);
    }
    else
    {
      /* initialize CRC peripheral with generating polynomial defined by user */
      if (HAL_CRCEx_Polynomial_Set(hcrc, hcrc->Init.GeneratingPolynomial, hcrc->Init.CRCLength) != HAL_OK)
      {
        return HAL_ERROR;
      }
    }
  
    /* check whether or not non-default CRC initial value has been
     * picked up by user */
    assert_param(IS_DEFAULT_INIT_VALUE(hcrc->Init.DefaultInitValueUse));
    if (hcrc->Init.DefaultInitValueUse == DEFAULT_INIT_VALUE_ENABLE)
    {
      WRITE_REG(hcrc->Instance->INIT, DEFAULT_CRC_INITVALUE);
    }
    else
    {
      WRITE_REG(hcrc->Instance->INIT, hcrc->Init.InitValue);
    }
  
  
    /* set input data inversion mode */
    assert_param(IS_CRC_INPUTDATA_INVERSION_MODE(hcrc->Init.InputDataInversionMode));
    MODIFY_REG(hcrc->Instance->CR, CRC_CR_REV_IN, hcrc->Init.InputDataInversionMode);
  
    /* set output data inversion mode */
    assert_param(IS_CRC_OUTPUTDATA_INVERSION_MODE(hcrc->Init.OutputDataInversionMode));
    MODIFY_REG(hcrc->Instance->CR, CRC_CR_REV_OUT, hcrc->Init.OutputDataInversionMode);
  
    /* makes sure the input data format (bytes, halfwords or words stream)
     * is properly specified by user */
    assert_param(IS_CRC_INPUTDATA_FORMAT(hcrc->InputDataFormat));
  
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_READY;
  
    /* Return function status */
    return HAL_OK;
  }
  
  /**
    * @brief  DeInitialize the CRC peripheral.
    * @param  hcrc CRC handle
    * @retval HAL status
    */
  HAL_StatusTypeDef HAL_CRC_DeInit(CRC_HandleTypeDef *hcrc)
  {
    /* Check the CRC handle allocation */
    if (hcrc == NULL)
    {
      return HAL_ERROR;
    }
  
    /* Check the parameters */
    assert_param(IS_CRC_ALL_INSTANCE(hcrc->Instance));
  
    /* Check the CRC peripheral state */
    if (hcrc->State == HAL_CRC_STATE_BUSY)
    {
      return HAL_BUSY;
    }
  
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_BUSY;
  
    /* Reset CRC calculation unit */
    __HAL_CRC_DR_RESET(hcrc);
  
    /* Reset IDR register content */
    CLEAR_BIT(hcrc->Instance->IDR, CRC_IDR_IDR);
  
    /* DeInit the low level hardware */
    HAL_CRC_MspDeInit(hcrc);
  
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_RESET;
  
    /* Process unlocked */
    __HAL_UNLOCK(hcrc);
  
    /* Return function status */
    return HAL_OK;
  }
  
  /**
    * @brief  Initializes the CRC MSP.
    * @param  hcrc CRC handle
    * @retval None
    */
  __weak void HAL_CRC_MspInit(CRC_HandleTypeDef *hcrc)
  {
    /* Prevent unused argument(s) compilation warning */
    UNUSED(hcrc);
  
    /* NOTE : This function should not be modified, when the callback is needed,
              the HAL_CRC_MspInit can be implemented in the user file
     */
  }
  
  /**
    * @brief  DeInitialize the CRC MSP.
    * @param  hcrc CRC handle
    * @retval None
    */
  __weak void HAL_CRC_MspDeInit(CRC_HandleTypeDef *hcrc)
  {
    /* Prevent unused argument(s) compilation warning */
    UNUSED(hcrc);
  
    /* NOTE : This function should not be modified, when the callback is needed,
              the HAL_CRC_MspDeInit can be implemented in the user file
     */
  }
  
  /**
    * @}
    */
  
  /** @defgroup CRC_Exported_Functions_Group2 Peripheral Control functions
   *  @brief    management functions.
   *
  @verbatim
   ===============================================================================
                        ##### Peripheral Control functions #####
   ===============================================================================
      [..]  This section provides functions allowing to:
        (+) compute the 7, 8, 16 or 32-bit CRC value of an 8, 16 or 32-bit data buffer
            using combination of the previous CRC value and the new one.
  
         [..]  or
  
        (+) compute the 7, 8, 16 or 32-bit CRC value of an 8, 16 or 32-bit data buffer
            independently of the previous CRC value.
  
  @endverbatim
    * @{
    */
  
  /**
    * @brief  Compute the 7, 8, 16 or 32-bit CRC value of an 8, 16 or 32-bit data buffer
    *         starting with the previously computed CRC as initialization value.
    * @param  hcrc CRC handle
    * @param  pBuffer pointer to the input data buffer, exact input data format is
    *         provided by hcrc->InputDataFormat.
    * @param  BufferLength input data buffer length (number of bytes if pBuffer
    *         type is * uint8_t, number of half-words if pBuffer type is * uint16_t,
    *         number of words if pBuffer type is * uint32_t).
    * @note  By default, the API expects a uint32_t pointer as input buffer parameter.
    *        Input buffer pointers with other types simply need to be cast in uint32_t
    *        and the API will internally adjust its input data processing based on the
    *        handle field hcrc->InputDataFormat.
    * @retval uint32_t CRC (returned value LSBs for CRC shorter than 32 bits)
    */
  uint32_t HAL_CRC_Accumulate(CRC_HandleTypeDef *hcrc, uint32_t pBuffer[], uint32_t BufferLength)
  {
    uint32_t index;      /* CRC input data buffer index */
    uint32_t temp = 0U;  /* CRC output (read from hcrc->Instance->DR register) */
  
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_BUSY;
  
    switch (hcrc->InputDataFormat)
    {
      case CRC_INPUTDATA_FORMAT_WORDS:
        /* Enter Data to the CRC calculator */
        for (index = 0U; index < BufferLength; index++)
        {
          hcrc->Instance->DR = pBuffer[index];
        }
        temp = hcrc->Instance->DR;
        break;
  
      case CRC_INPUTDATA_FORMAT_BYTES:
        temp = CRC_Handle_8(hcrc, (uint8_t *)pBuffer, BufferLength);
        break;
  
      case CRC_INPUTDATA_FORMAT_HALFWORDS:
        temp = CRC_Handle_16(hcrc, (uint16_t *)(void *)pBuffer, BufferLength);    /* Derogation MisraC2012 R.11.5 */
        break;
      default:
        break;
    }
  
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_READY;
  
    /* Return the CRC computed value */
    return temp;
  }
  
  /**
    * @brief  Compute the 7, 8, 16 or 32-bit CRC value of an 8, 16 or 32-bit data buffer
    *         starting with hcrc->Instance->INIT as initialization value.
    * @param  hcrc CRC handle
    * @param  pBuffer pointer to the input data buffer, exact input data format is
    *         provided by hcrc->InputDataFormat.
    * @param  BufferLength input data buffer length (number of bytes if pBuffer
    *         type is * uint8_t, number of half-words if pBuffer type is * uint16_t,
    *         number of words if pBuffer type is * uint32_t).
    * @note  By default, the API expects a uint32_t pointer as input buffer parameter.
    *        Input buffer pointers with other types simply need to be cast in uint32_t
    *        and the API will internally adjust its input data processing based on the
    *        handle field hcrc->InputDataFormat.
    * @retval uint32_t CRC (returned value LSBs for CRC shorter than 32 bits)
    */
  uint32_t HAL_CRC_Calculate(CRC_HandleTypeDef *hcrc, uint32_t pBuffer[], uint32_t BufferLength)
  {
    uint32_t index;      /* CRC input data buffer index */
    uint32_t temp = 0U;  /* CRC output (read from hcrc->Instance->DR register) */
  
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_BUSY;
  
    /* Reset CRC Calculation Unit (hcrc->Instance->INIT is
    *  written in hcrc->Instance->DR) */
    __HAL_CRC_DR_RESET(hcrc);
  
    switch (hcrc->InputDataFormat)
    {
      case CRC_INPUTDATA_FORMAT_WORDS:
        /* Enter 32-bit input data to the CRC calculator */
        for (index = 0U; index < BufferLength; index++)
        {
          hcrc->Instance->DR = pBuffer[index];
        }
        temp = hcrc->Instance->DR;
        break;
  
      case CRC_INPUTDATA_FORMAT_BYTES:
        /* Specific 8-bit input data handling  */
        temp = CRC_Handle_8(hcrc, (uint8_t *)pBuffer, BufferLength);
        break;
  
      case CRC_INPUTDATA_FORMAT_HALFWORDS:
        /* Specific 16-bit input data handling  */
        temp = CRC_Handle_16(hcrc, (uint16_t *)(void *)pBuffer, BufferLength);    /* Derogation MisraC2012 R.11.5 */
        break;
  
      default:
        break;
    }
  
    /* Change CRC peripheral state */
    hcrc->State = HAL_CRC_STATE_READY;
  
    /* Return the CRC computed value */
    return temp;
  }
  
  /**
    * @}
    */
  
  /** @defgroup CRC_Exported_Functions_Group3 Peripheral State functions
   *  @brief    Peripheral State functions.
   *
  @verbatim
   ===============================================================================
                        ##### Peripheral State functions #####
   ===============================================================================
      [..]
      This subsection permits to get in run-time the status of the peripheral.
  
  @endverbatim
    * @{
    */
  
  /**
    * @brief  Return the CRC handle state.
    * @param  hcrc CRC handle
    * @retval HAL state
    */
  HAL_CRC_StateTypeDef HAL_CRC_GetState(CRC_HandleTypeDef *hcrc)
  {
    /* Return CRC handle state */
    return hcrc->State;
  }
  
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  /** @addtogroup CRC_Private_Functions
   * @{
   */
  
  /**
    * @brief  Enter 8-bit input data to the CRC calculator.
    *         Specific data handling to optimize processing time.
    * @param  hcrc CRC handle
    * @param  pBuffer pointer to the input data buffer
    * @param  BufferLength input data buffer length
    * @retval uint32_t CRC (returned value LSBs for CRC shorter than 32 bits)
    */
  static uint32_t CRC_Handle_8(CRC_HandleTypeDef *hcrc, uint8_t pBuffer[], uint32_t BufferLength)
  {
    uint32_t i; /* input data buffer index */
    uint16_t data;
    __IO uint16_t *pReg;
  
    /* Processing time optimization: 4 bytes are entered in a row with a single word write,
     * last bytes must be carefully fed to the CRC calculator to ensure a correct type
     * handling by the peripheral */
    for (i = 0U; i < (BufferLength / 4U); i++)
    {
      hcrc->Instance->DR = ((uint32_t)pBuffer[4U * i] << 24U) | \
                           ((uint32_t)pBuffer[(4U * i) + 1U] << 16U) | \
                           ((uint32_t)pBuffer[(4U * i) + 2U] << 8U)  | \
                           (uint32_t)pBuffer[(4U * i) + 3U];
    }
    /* last bytes specific handling */
    if ((BufferLength % 4U) != 0U)
    {
      if ((BufferLength % 4U) == 1U)
      {
        *(__IO uint8_t *)(__IO void *)(&hcrc->Instance->DR) = pBuffer[4U * i];         /* Derogation MisraC2012 R.11.5 */
      }
      if ((BufferLength % 4U) == 2U)
      {
        data = ((uint16_t)(pBuffer[4U * i]) << 8U) | (uint16_t)pBuffer[(4U * i) + 1U];
        pReg = (__IO uint16_t *)(__IO void *)(&hcrc->Instance->DR);                    /* Derogation MisraC2012 R.11.5 */
        *pReg = data;
      }
      if ((BufferLength % 4U) == 3U)
      {
        data = ((uint16_t)(pBuffer[4U * i]) << 8U) | (uint16_t)pBuffer[(4U * i) + 1U];
        pReg = (__IO uint16_t *)(__IO void *)(&hcrc->Instance->DR);                    /* Derogation MisraC2012 R.11.5 */
        *pReg = data;
  
        *(__IO uint8_t *)(__IO void *)(&hcrc->Instance->DR) = pBuffer[(4U * i) + 2U];  /* Derogation MisraC2012 R.11.5 */
      }
    }
  
    /* Return the CRC computed value */
    return hcrc->Instance->DR;
  }
  
  /**
    * @brief  Enter 16-bit input data to the CRC calculator.
    *         Specific data handling to optimize processing time.
    * @param  hcrc CRC handle
    * @param  pBuffer pointer to the input data buffer
    * @param  BufferLength input data buffer length
    * @retval uint32_t CRC (returned value LSBs for CRC shorter than 32 bits)
    */
  static uint32_t CRC_Handle_16(CRC_HandleTypeDef *hcrc, uint16_t pBuffer[], uint32_t BufferLength)
  {
    uint32_t i;  /* input data buffer index */
    __IO uint16_t *pReg;
  
    /* Processing time optimization: 2 HalfWords are entered in a row with a single word write,
     * in case of odd length, last HalfWord must be carefully fed to the CRC calculator to ensure
     * a correct type handling by the peripheral */
    for (i = 0U; i < (BufferLength / 2U); i++)
    {
      hcrc->Instance->DR = ((uint32_t)pBuffer[2U * i] << 16U) | (uint32_t)pBuffer[(2U * i) + 1U];
    }
    if ((BufferLength % 2U) != 0U)
    {
      pReg = (__IO uint16_t *)(__IO void *)(&hcrc->Instance->DR);                 /* Derogation MisraC2012 R.11.5 */
      *pReg = pBuffer[2U * i];
    }
  
    /* Return the CRC computed value */
    return hcrc->Instance->DR;
  }
  
  /**
    * @}
    */
  
  #endif /* HAL_CRC_MODULE_ENABLED */
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
  