/**
  ******************************************************************************
  * @file    stm32l4xx_hal_rng.c
  * @author  MCD Application Team
  * @brief   RNG HAL module driver.
  *          This file provides firmware functions to manage the following 
  *          functionalities of the Random Number Generator (RNG) peripheral:
  *           + Initialization/de-initialization functions
  *           + Peripheral Control functions 
  *           + Peripheral State functions
  *         
  @verbatim
  ==============================================================================
                     ##### How to use this driver #####
  ==============================================================================
  [..]
      The RNG HAL driver can be used as follows:

      (#) Enable the RNG controller clock using __HAL_RCC_RNG_CLK_ENABLE() macro 
          in HAL_RNG_MspInit().
      (#) Activate the RNG peripheral using HAL_RNG_Init() function.
      (#) Wait until the 32-bit Random Number Generator contains a valid 
          random data using (polling/interrupt) mode.   
      (#) Get the 32 bit random number using HAL_RNG_GenerateRandomNumber() function.
  
  @endverbatim
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT(c) 2017 STMicroelectronics</center></h2>
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
  *   1. Redistributions of source code must retain the above copyright notice,
  *      this list of conditions and the following disclaimer.
  *   2. Redistributions in binary form must reproduce the above copyright notice,
  *      this list of conditions and the following disclaimer in the documentation
  *      and/or other materials provided with the distribution.
  *   3. Neither the name of STMicroelectronics nor the names of its contributors
  *      may be used to endorse or promote products derived from this software
  *      without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************
  */ 

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

/** @addtogroup STM32L4xx_HAL_Driver
  * @{
  */

/** @defgroup RNG RNG
  * @brief RNG HAL module driver.
  * @{
  */

#ifdef HAL_RNG_MODULE_ENABLED



/* Private types -------------------------------------------------------------*/
/* Private defines -----------------------------------------------------------*/
/** @defgroup RNG_Private_Constants RNG_Private_Constants
  * @{
  */
#define RNG_TIMEOUT_VALUE     2
/**
  * @}
  */ 

/* Private macros ------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/
/* Exported functions --------------------------------------------------------*/

/** @addtogroup RNG_Exported_Functions
  * @{
  */

/** @addtogroup RNG_Exported_Functions_Group1
 *  @brief   Initialization and de-initialization functions
 *
@verbatim
 ===============================================================================
          ##### Initialization and de-initialization functions #####
 ===============================================================================
    [..]  This section provides functions allowing to:
      (+) Initialize the RNG according to the specified parameters 
          in the RNG_InitTypeDef and create the associated handle
      (+) DeInitialize the RNG peripheral
      (+) Initialize the RNG MSP (MCU Specific Package)
      (+) DeInitialize the RNG MSP 
 
@endverbatim
  * @{
  */

/**
  * @brief  Initialize the RNG peripheral and initialize the associated handle.
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_RNG_Init(RNG_HandleTypeDef *hrng)
{ 
  /* Check the RNG handle allocation */
  if(hrng == NULL)
  {
    return HAL_ERROR;
  }

  assert_param(IS_RNG_ALL_INSTANCE(hrng->Instance));
#if defined(RNG_CR_CED)
  assert_param(IS_RNG_CED(hrng->Init.ClockErrorDetection));
#endif /* defined(RNG_CR_CED) */

  if(hrng->State == HAL_RNG_STATE_RESET)
  {  
    /* Allocate lock resource and initialize it */
    hrng->Lock = HAL_UNLOCKED;

    /* Init the low level hardware */
    HAL_RNG_MspInit(hrng);
  }

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

#if defined(RNG_CR_CED)
  /* Clock Error Detection configuration */
  MODIFY_REG(hrng->Instance->CR, RNG_CR_CED, hrng->Init.ClockErrorDetection);
#endif /* defined(RNG_CR_CED) */

  /* Enable the RNG Peripheral */
  __HAL_RNG_ENABLE(hrng);

  /* Initialize the RNG state */
  hrng->State = HAL_RNG_STATE_READY;
  
  /* Return function status */
  return HAL_OK;
}

/**
  * @brief  DeInitialize the RNG peripheral. 
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_RNG_DeInit(RNG_HandleTypeDef *hrng)
{ 
  /* Check the RNG handle allocation */
  if(hrng == NULL)
  {
    return HAL_ERROR;
  }
  
#if defined(RNG_CR_CED)
  /* Clear Clock Error Detection bit */
  CLEAR_BIT(hrng->Instance->CR, RNG_CR_CED);
#endif /* defined(RNG_CR_CED) */

  /* Disable the RNG Peripheral */
  CLEAR_BIT(hrng->Instance->CR, RNG_CR_IE | RNG_CR_RNGEN);

  /* Clear RNG interrupt status flags */
  CLEAR_BIT(hrng->Instance->SR, RNG_SR_CEIS | RNG_SR_SEIS);

  /* DeInit the low level hardware */
  HAL_RNG_MspDeInit(hrng);

  /* Update the RNG state */
  hrng->State = HAL_RNG_STATE_RESET; 

  /* Release Lock */
  __HAL_UNLOCK(hrng);

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

/**
  * @brief  Initialize the RNG MSP.
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @retval None
  */
__weak void HAL_RNG_MspInit(RNG_HandleTypeDef *hrng)
{
  /* Prevent unused argument(s) compilation warning */
  UNUSED(hrng);

  /* NOTE : This function should not be modified. When the callback is needed,
            function HAL_RNG_MspInit must be implemented in the user file.
   */
}

/**
  * @brief  DeInitialize the RNG MSP.
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @retval None
  */
__weak void HAL_RNG_MspDeInit(RNG_HandleTypeDef *hrng)
{
  /* Prevent unused argument(s) compilation warning */
  UNUSED(hrng);

  /* NOTE : This function should not be modified. When the callback is needed,
            function HAL_RNG_MspDeInit must be implemented in the user file.
   */
}

/**
  * @}
  */

/** @addtogroup RNG_Exported_Functions_Group2
 *  @brief    Management functions. 
 *
@verbatim   
 ===============================================================================
                      ##### Peripheral Control functions #####
 ===============================================================================  
    [..]  This section provides functions allowing to:
      (+) Get the 32 bit Random number
      (+) Get the 32 bit Random number with interrupt enabled
      (+) Handle RNG interrupt request 

@endverbatim
  * @{
  */

/**
  * @brief  Generate a 32-bit random number.
  * @note   Each time the random number data is read the RNG_FLAG_DRDY flag 
  *         is automatically cleared.
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @param  random32bit: pointer to generated random number variable if successful.
  * @retval HAL status
  */

HAL_StatusTypeDef HAL_RNG_GenerateRandomNumber(RNG_HandleTypeDef *hrng, uint32_t *random32bit)
{
  uint32_t tickstart = 0;    
  HAL_StatusTypeDef status = HAL_OK;

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

    /* Get tick */
    tickstart = HAL_GetTick();
  
    /* Check if data register contains valid random data */
    while(__HAL_RNG_GET_FLAG(hrng, RNG_FLAG_DRDY) == RESET)
    {
      if((HAL_GetTick() - tickstart ) > RNG_TIMEOUT_VALUE)
      {    
        hrng->State = HAL_RNG_STATE_ERROR;

        /* Process Unlocked */
        __HAL_UNLOCK(hrng);
      
        return HAL_TIMEOUT;
      } 
    }
  
    /* Get a 32bit Random number */
    hrng->RandomNumber = hrng->Instance->DR;
    *random32bit = hrng->RandomNumber;
  
    hrng->State = HAL_RNG_STATE_READY;
  }
  else
  {
    status = HAL_ERROR;
  }
  
  /* Process Unlocked */
  __HAL_UNLOCK(hrng);

  return status;
}

/**
  * @brief  Generate a 32-bit random number in interrupt mode.
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_RNG_GenerateRandomNumber_IT(RNG_HandleTypeDef *hrng)
{
  HAL_StatusTypeDef status = HAL_OK;
  
  /* Process Locked */
  __HAL_LOCK(hrng);
  
  /* Check RNG peripheral state */
  if(hrng->State == HAL_RNG_STATE_READY)
  {
    /* Change RNG peripheral state */  
    hrng->State = HAL_RNG_STATE_BUSY;  
  
    /* Process Unlocked */
    __HAL_UNLOCK(hrng);
    
    /* Enable the RNG Interrupts: Data Ready, Clock error, Seed error */ 
    __HAL_RNG_ENABLE_IT(hrng);
  }
  else
  {
    /* Process Unlocked */
    __HAL_UNLOCK(hrng);
    
    status = HAL_ERROR;
  }
  
  return status;
}

/**
  * @brief  Handle RNG interrupt request.
  * @note   In the case of a clock error, the RNG is no more able to generate 
  *         random numbers because the PLL48CLK clock is not correct. User has 
  *         to check that the clock controller is correctly configured to provide
  *         the RNG clock and clear the CEIS bit using __HAL_RNG_CLEAR_IT(). 
  *         The clock error has no impact on the previously generated 
  *         random numbers, and the RNG_DR register contents can be used.
  * @note   In the case of a seed error, the generation of random numbers is 
  *         interrupted as long as the SECS bit is '1'. If a number is 
  *         available in the RNG_DR register, it must not be used because it may 
  *         not have enough entropy. In this case, it is recommended to clear the 
  *         SEIS bit using __HAL_RNG_CLEAR_IT(), then disable and enable 
  *         the RNG peripheral to reinitialize and restart the RNG.
  * @note   User-written HAL_RNG_ErrorCallback() API is called once whether SEIS
  *         or CEIS are set.  
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @retval None

  */
void HAL_RNG_IRQHandler(RNG_HandleTypeDef *hrng)
{
  /* RNG clock error interrupt occurred */
  if((__HAL_RNG_GET_IT(hrng, RNG_IT_CEI) != RESET) ||  (__HAL_RNG_GET_IT(hrng, RNG_IT_SEI) != RESET))
  { 
    /* Change RNG peripheral state */
    hrng->State = HAL_RNG_STATE_ERROR;
  
    HAL_RNG_ErrorCallback(hrng);
    
    /* Clear the clock error flag */
    __HAL_RNG_CLEAR_IT(hrng, RNG_IT_CEI|RNG_IT_SEI);
    
  }
  
  /* Check RNG data ready interrupt occurred */    
  if(__HAL_RNG_GET_IT(hrng, RNG_IT_DRDY) != RESET)
  {
    /* Generate random number once, so disable the IT */
    __HAL_RNG_DISABLE_IT(hrng);
    
    /* Get the 32bit Random number (DRDY flag automatically cleared) */ 
    hrng->RandomNumber = hrng->Instance->DR;
    
    if(hrng->State != HAL_RNG_STATE_ERROR)
    {
      /* Change RNG peripheral state */
      hrng->State = HAL_RNG_STATE_READY; 
      
      /* Data Ready callback */ 
      HAL_RNG_ReadyDataCallback(hrng, hrng->RandomNumber);
    } 
  }
} 

/**
  * @brief  Return generated random number in polling mode (Obsolete).
  * @note   Use HAL_RNG_GenerateRandomNumber() API instead.
  * @param  hrng: pointer to a RNG_HandleTypeDef structure that contains
  *                the configuration information for RNG.
  * @retval random value
  */
uint32_t HAL_RNG_GetRandomNumber(RNG_HandleTypeDef *hrng)
{
  if(HAL_RNG_GenerateRandomNumber(hrng, &(hrng->RandomNumber)) == HAL_OK)
  {
    return hrng->RandomNumber; 
  }
  else
  {
    return 0;
  }
}


/**
  * @brief  Return a 32-bit random number with interrupt enabled (Obsolete).
  * @note   Use HAL_RNG_GenerateRandomNumber_IT() API instead.
  * @param  hrng: RNG handle
  * @retval 32-bit random number
  */
uint32_t HAL_RNG_GetRandomNumber_IT(RNG_HandleTypeDef *hrng)
{
  uint32_t random32bit = 0;
  
  /* Process locked */
  __HAL_LOCK(hrng);
  
  /* Change RNG peripheral state */  
  hrng->State = HAL_RNG_STATE_BUSY;  
  
  /* Get a 32bit Random number */ 
  random32bit = hrng->Instance->DR;
  
  /* Enable the RNG Interrupts: Data Ready, Clock error, Seed error */ 
  __HAL_RNG_ENABLE_IT(hrng); 
  
  /* Return the 32 bit random number */   
  return random32bit;
}



/**
  * @brief  Read latest generated random number. 
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @retval random value
  */
uint32_t HAL_RNG_ReadLastRandomNumber(RNG_HandleTypeDef *hrng)
{
  return(hrng->RandomNumber);
}

/**
  * @brief  Data Ready callback in non-blocking mode. 
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @param  random32bit: generated random value
  * @retval None
  */
__weak void HAL_RNG_ReadyDataCallback(RNG_HandleTypeDef *hrng, uint32_t random32bit)
{
  /* Prevent unused argument(s) compilation warning */
  UNUSED(hrng);
  UNUSED(random32bit);

  /* NOTE : This function should not be modified. When the callback is needed,
            function HAL_RNG_ReadyDataCallback must be implemented in the user file.
   */
}

/**
  * @brief  RNG error callback.
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @retval None
  */
__weak void HAL_RNG_ErrorCallback(RNG_HandleTypeDef *hrng)
{
  /* Prevent unused argument(s) compilation warning */
  UNUSED(hrng);

  /* NOTE : This function should not be modified. When the callback is needed,
            function HAL_RNG_ErrorCallback must be implemented in the user file.
   */
}
 
/**
  * @}
  */

/** @addtogroup RNG_Exported_Functions_Group3
 *  @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 RNG handle state.
  * @param  hrng: pointer to a RNG_HandleTypeDef structure.
  * @retval HAL state
  */
HAL_RNG_StateTypeDef HAL_RNG_GetState(RNG_HandleTypeDef *hrng)
{
  /* Return RNG handle state */
  return hrng->State;
}

/**
  * @}
  */

/**
  * @}
  */


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

/**
  * @}
  */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/