/**
  ******************************************************************************
  * @file    stm32l4xx_hal_rng_ex.c
  * @author  MCD Application Team
  * @brief   Extended RNG HAL module driver.
  *          This file provides firmware functions to manage the following
  *          functionalities of the Random Number Generator (RNG) peripheral:
  *           + Lock configuration functions
  *           + Reset the RNG
  *
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2017 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.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "stm32l4xx_hal.h"

/** @addtogroup STM32L4xx_HAL_Driver
  * @{
  */

#if defined(RNG)

/** @addtogroup RNG_Ex
  * @brief RNG Extended HAL module driver.
  * @{
  */

#ifdef HAL_RNG_MODULE_ENABLED
#if defined(RNG_CR_CONDRST)
/* Private types -------------------------------------------------------------*/
/* Private defines -----------------------------------------------------------*/
#if defined(RNG_VER_3_2) || defined(RNG_VER_3_1) || defined(RNG_VER_3_0)
/** @addtogroup RNGEx_Private_Defines
  * @{
  */
/*  Health test control register information to use in CCM algorithm are defined in CMSIS Device file.
    - RNG_HTCFG : Default HTCR register value for best latency and NIST Compliance
    - RNG_HTCFG_1 : Magic number value that must be written to RNG_HTCR register
      immediately before reading or writing RNG_HTCR register */
/**
  * @}
  */
#endif /* RNG_VER_3_2 || RNG_VER_3_1 || RNG_VER_3_0 */
/* Private variables ---------------------------------------------------------*/
/* Private constants ---------------------------------------------------------*/
/** @addtogroup RNG_Ex_Private_Constants
  * @{
  */
#define RNG_TIMEOUT_VALUE     2U
/**
  * @}
  */
/* Private macros ------------------------------------------------------------*/
/* Private functions prototypes ----------------------------------------------*/
/* Private functions  --------------------------------------------------------*/
/* Exported functions --------------------------------------------------------*/

/** @defgroup RNG_Ex_Exported_Functions RNG_Ex Exported Functions
  * @{
  */

/** @defgroup RNG_Ex_Exported_Functions_Group1 Configuration and lock functions
  *  @brief   Configuration functions
  *
@verbatim
 ===============================================================================
          ##### Configuration and lock functions #####
 ===============================================================================
    [..]  This section provides functions allowing to:
      (+) Configure the RNG with the specified parameters in the RNG_ConfigTypeDef
      (+) Lock RNG configuration Allows user to lock a configuration until next reset.

@endverbatim
  * @{
  */

/**
  * @brief  Configure the RNG with the specified parameters in the
  *         RNG_ConfigTypeDef.
  * @param  hrng pointer to a RNG_HandleTypeDef structure that contains
  *          the configuration information for RNG.
  * @param  pConf pointer to a RNG_ConfigTypeDef structure that contains
  *         the configuration information for RNG module

  * @retval HAL status
  */
HAL_StatusTypeDef HAL_RNGEx_SetConfig(RNG_HandleTypeDef *hrng, const RNG_ConfigTypeDef *pConf)
{
  uint32_t tickstart;
  uint32_t cr_value;
  HAL_StatusTypeDef status ;

  /* Check the RNG handle allocation */
  if ((hrng == NULL) || (pConf == NULL))
  {
    return HAL_ERROR;
  }

  /* Check the parameters */
  assert_param(IS_RNG_ALL_INSTANCE(hrng->Instance));
  assert_param(IS_RNG_CLOCK_DIVIDER(pConf->ClockDivider));
  assert_param(IS_RNG_NIST_COMPLIANCE(pConf->NistCompliance));
  assert_param(IS_RNG_CONFIG1(pConf->Config1));
  assert_param(IS_RNG_CONFIG2(pConf->Config2));
  assert_param(IS_RNG_CONFIG3(pConf->Config3));

  /* Check RNG peripheral state */
  if (hrng->State == HAL_RNG_STATE_READY)
  {
    /* Change RNG peripheral state */
    hrng->State = HAL_RNG_STATE_BUSY;

    /* Disable RNG */
    __HAL_RNG_DISABLE(hrng);

    /* RNG CR register configuration. Set value in CR register for :
        - NIST Compliance setting
        - Clock divider value
        - CONFIG 1, CONFIG 2 and CONFIG 3 values */

    cr_value = (uint32_t)(pConf->ClockDivider | pConf->NistCompliance
                          | (pConf->Config1 << RNG_CR_RNG_CONFIG1_Pos)
                          | (pConf->Config2 << RNG_CR_RNG_CONFIG2_Pos)
                          | (pConf->Config3 << RNG_CR_RNG_CONFIG3_Pos));

    MODIFY_REG(hrng->Instance->CR, RNG_CR_NISTC | RNG_CR_CLKDIV | RNG_CR_RNG_CONFIG1
               | RNG_CR_RNG_CONFIG2 | RNG_CR_RNG_CONFIG3,
               (uint32_t)(RNG_CR_CONDRST | cr_value));

#if defined(RNG_VER_3_2) || defined(RNG_VER_3_1) || defined(RNG_VER_3_0)
    /*!< magic number must be written immediately before to RNG_HTCRG */
    WRITE_REG(hrng->Instance->HTCR, RNG_HTCFG_1);
    /* for best latency and to be compliant with NIST */
    WRITE_REG(hrng->Instance->HTCR, RNG_HTCFG);
#endif /* RNG_VER_3_2 || RNG_VER_3_1 || RNG_VER_3_0 */

    /* Writing bit CONDRST=0*/
    CLEAR_BIT(hrng->Instance->CR, RNG_CR_CONDRST);
    /* Get tick */
    tickstart = HAL_GetTick();

    /* Wait for conditioning reset process to be completed */
    while (HAL_IS_BIT_SET(hrng->Instance->CR, RNG_CR_CONDRST))
    {
      if ((HAL_GetTick() - tickstart) > RNG_TIMEOUT_VALUE)
      {
        /* New check to avoid false timeout detection in case of prememption */
        if (HAL_IS_BIT_SET(hrng->Instance->CR, RNG_CR_CONDRST))
        {
          hrng->State = HAL_RNG_STATE_READY;
          hrng->ErrorCode = HAL_RNG_ERROR_TIMEOUT;
          return HAL_ERROR;
        }
      }
    }

    /* Enable RNG */
    __HAL_RNG_ENABLE(hrng);

    /* Initialize the RNG state */
    hrng->State = HAL_RNG_STATE_READY;

    /* function status */
    status = HAL_OK;
  }
  else
  {
    hrng->ErrorCode = HAL_RNG_ERROR_BUSY;
    status = HAL_ERROR;
  }

  /* Return the function status */
  return status;
}

/**
  * @brief  Get the RNG Configuration and fill parameters in the
  *         RNG_ConfigTypeDef.
  * @param  hrng pointer to a RNG_HandleTypeDef structure that contains
  *          the configuration information for RNG.
  * @param  pConf pointer to a RNG_ConfigTypeDef structure that contains
  *         the configuration information for RNG module

  * @retval HAL status
  */
HAL_StatusTypeDef HAL_RNGEx_GetConfig(RNG_HandleTypeDef *hrng, RNG_ConfigTypeDef *pConf)
{

  HAL_StatusTypeDef status ;

  /* Check the RNG handle allocation */
  if ((hrng == NULL) || (pConf == NULL))
  {
    return HAL_ERROR;
  }

  /* Check RNG peripheral state */
  if (hrng->State == HAL_RNG_STATE_READY)
  {
    /* Change RNG peripheral state */
    hrng->State = HAL_RNG_STATE_BUSY;

    /* Get  RNG parameters  */
    pConf->Config1        = (uint32_t)((hrng->Instance->CR & RNG_CR_RNG_CONFIG1) >> RNG_CR_RNG_CONFIG1_Pos) ;
    pConf->Config2        = (uint32_t)((hrng->Instance->CR & RNG_CR_RNG_CONFIG2) >> RNG_CR_RNG_CONFIG2_Pos);
    pConf->Config3        = (uint32_t)((hrng->Instance->CR & RNG_CR_RNG_CONFIG3) >> RNG_CR_RNG_CONFIG3_Pos);
    pConf->ClockDivider   = (hrng->Instance->CR & RNG_CR_CLKDIV);
    pConf->NistCompliance = (hrng->Instance->CR & RNG_CR_NISTC);

    /* Initialize the RNG state */
    hrng->State = HAL_RNG_STATE_READY;

    /* function status */
    status = HAL_OK;
  }
  else
  {
    hrng->ErrorCode |= HAL_RNG_ERROR_BUSY;
    status = HAL_ERROR;
  }

  /* Return the function status */
  return status;
}

/**
  * @brief  RNG current configuration lock.
  * @note   This function allows to lock RNG peripheral configuration.
  *         Once locked, HW RNG reset has to be performed prior any further
  *         configuration update.
  * @param  hrng pointer to a RNG_HandleTypeDef structure that contains
  *                the configuration information for RNG.
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_RNGEx_LockConfig(RNG_HandleTypeDef *hrng)
{
  HAL_StatusTypeDef status;

  /* Check the RNG handle allocation */
  if (hrng == NULL)
  {
    return HAL_ERROR;
  }

  /* Check RNG peripheral state */
  if (hrng->State == HAL_RNG_STATE_READY)
  {
    /* Change RNG peripheral state */
    hrng->State = HAL_RNG_STATE_BUSY;

    /* Perform RNG configuration Lock */
    MODIFY_REG(hrng->Instance->CR, RNG_CR_CONFIGLOCK, RNG_CR_CONFIGLOCK);

    /* Change RNG peripheral state */
    hrng->State = HAL_RNG_STATE_READY;

    /* function status */
    status = HAL_OK;
  }
  else
  {
    hrng->ErrorCode = HAL_RNG_ERROR_BUSY;
    status = HAL_ERROR;
  }

  /* Return the function status */
  return status;
}


/**
  * @}
  */

/** @defgroup RNG_Ex_Exported_Functions_Group2 Recover from seed error function
  *  @brief   Recover from seed error function
  *
@verbatim
 ===============================================================================
          ##### Recover from seed error function #####
 ===============================================================================
    [..]  This section provide function allowing to:
      (+) Recover from a seed error

@endverbatim
  * @{
  */

/**
  * @brief  RNG sequence to recover from a seed error
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_RNGEx_RecoverSeedError(RNG_HandleTypeDef *hrng)
{
  HAL_StatusTypeDef status;

  /* Check the RNG handle allocation */
  if (hrng == NULL)
  {
    return HAL_ERROR;
  }

  /* Check RNG peripheral state */
  if (hrng->State == HAL_RNG_STATE_READY)
  {
    /* Change RNG peripheral state */
    hrng->State = HAL_RNG_STATE_BUSY;

    /* sequence to fully recover from a seed error */
    status = RNG_RecoverSeedError(hrng);
  }
  else
  {
    hrng->ErrorCode = HAL_RNG_ERROR_BUSY;
    status = HAL_ERROR;
  }

  /* Return the function status */
  return status;
}

/**
  * @}
  */

/**
  * @}
  */

#endif /* RNG_CR_CONDRST */
#endif /* HAL_RNG_MODULE_ENABLED */
/**
  * @}
  */

#endif /* RNG */

/**
  * @}
  */