rng.h

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#ifndef RNG_H_INCLUDED
#define RNG_H_INCLUDED

/**********************************************************************/
/*
 * Copyright (c) 2013-2015, Jetro AS
 * All rights reserved.
 *
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONRIBUTORS ``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 AUTHOR 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.
 *
 * This file is part of the EVE platform.
 */

/**
 * \file
 * @brief Hardware random number generator driver.
 *
 * @author SE, Jetro AS
 */ /******************************************************************/

#include <stdbool.h>
#include <stdint.h>

#include <hal/nrf_rng.h>
#include <sdk_errors.h>

/**
 * \defgroup rng nRF52 HW Random number generator
 * \brief nRF52 hardware random number generator (RNG) APIs.
 * \ingroup nrf52
 * \{
 */

/** @brief Struct for RNG configuration. */
struct rng_config_t
{
  bool    error_correction;      /**< Error correction flag. */
  uint8_t interrupt_priority;    /**< interrupt priority */
};

/** @brief RNG default configuration. */
#define NRF_DRV_RNG_DEFAULT_CONFIG                            \
  {                                                           \
    .error_correction   = RNG_CONFIG_ERROR_CORRECTION,        \
    .interrupt_priority = RNG_CONFIG_IRQ_PRIORITY,            \
  }

/**
 * @brief Function for initializing the nrf_drv_rng module.
 * @retval  NRF_SUCCESS                       Driver was successfully initialized.
 * @retval  NRF_ERROR_INVALID_STATE           Driver was already initialized.
 * @retval  NRF_ERROR_INVALID_LENGTH          Pool size have to be a power of 2.
 * @retval  NRF_ERROR_SOFTDEVICE_NOT_ENABLED  SoftDevice is present, but not enabled.
 */
uint32_t RngInit(void);

/**
 * @brief Function for deinitializing the nrf_drv_rng module.
 */
void RngDeinit(void);

/**
 * @brief Function for getting the number of currently available random bytes.
 * @param[out] bytes_available   The number of bytes currently available in the pool.
 * @retval     NRF_SUCCESS       If the number of available random bytes was written to bytes_available.
 */
uint32_t RngBytesAvailable(uint8_t* bytes_available);

/**
 * @brief Function for querying the capacity of the application random pool.
 * @param[out] pool_capacity     The capacity of the pool.
 * @retval     NRF_SUCCESS       If the capacity of the pool was written to pool_capacity.
 */
uint32_t RngPoolCapacity(uint8_t* pool_capacity);

/**
 * @brief Function for getting the vector of random numbers.
 * @param[out] buffer                               Pointer to uint8_t buffer for storing the bytes.
 * @param[in]  length                               Number of bytes to take from the pool and place in buffer.
 * @retval     NRF_SUCCESS                          If the requested bytes were written to buffer.
 * @retval     NRF_ERROR_NO_MEM                     If no bytes were written to the buffer
 * @retval     NRF_ERROR_SOC_RAND_NOT_ENOUGH_VALUES If no bytes were written to the buffer
 */
uint32_t RngRand(uint8_t* buffer, uint8_t length);

/**
 * @brief Blocking function for getting an arbitrary array of random numbers.
 * @note This function may execute for a substantial amount of time depending on the length of the buffer
 *       required and on the state of the current internal pool of random numbers.
 * @param[out] buffer                               Pointer to buffer for storing the bytes.
 * @param[in]  length                               Number of bytes place in buffer.
 * @retval     NRF_SUCCESS                          If the requested bytes were written to buffer.
 */
uint32_t RngBlockRand(uint8_t* buffer, uint32_t length);

/** @} rng */

#endif // RNG_H_INCLUDED