/**
 * @file
 * @brief      Pseudo-random number generator(PRNG) Peripheral Module.
 * @note       The PRNG hardware does not produce true random numbers. The
 *             output should be used as a seed to an approved random-number
 *             algorithm, per a certifying authority such as NIST or PCI. The
 *             approved algorithm will output random numbers which are cerfitied
 *             for use in encryption and authentication algorithms.
 */
/* ****************************************************************************
 * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Except as contained in this notice, the name of Maxim Integrated
 * Products, Inc. shall not be used except as stated in the Maxim Integrated
 * Products, Inc. Branding Policy.
 *
 * The mere transfer of this software does not imply any licenses
 * of trade secrets, proprietary technology, copyrights, patents,
 * trademarks, maskwork rights, or any other form of intellectual
 * property whatsoever. Maxim Integrated Products, Inc. retains all
 * ownership rights.
 *
 * $Date: 2016-10-10 19:26:15 -0500 (Mon, 10 Oct 2016) $
 * $Revision: 24668 $
 *
 ******************************************************************************/

/* **** Includes **** */
#include "prng_regs.h"

/* Define to prevent redundant inclusion */
#ifndef _PRNG_H_
#define _PRNG_H_

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @ingroup    periphlibs
 * @defgroup   prng Pseudo-Random Number Generator (PRNG)
 * @brief      Pseudo-random number generator(PRNG) Peripheral Module.
 * @note       The PRNG hardware does not produce true random numbers. The
 *             output should be used as a seed to an approved random-number
 *             algorithm, per a certifying authority such as NIST or PCI. The
 *             approved algorithm will output random numbers which are cerfitied
 *             for use in encryption and authentication algorithms.
 * @{
 */

/* **** Definitions **** */

/* **** Globals **** */

/* **** Function Prototypes **** */

/**
 * @brief      Initialize required clocks and enable PRNG module
 * @note       This function will set the clock divisors to divide by 1 if they are disabled.
 *             Otherwise, the clock divisors are left unchanged.
 */
void PRNG_Init(void);

/**
 * @brief      Returns ready bit to indicates that the PRNG_GetSeed can be
 *             called without being held off. Only needs to be called one time after a POR event.
 *
 * @retval     0         PRNG not ready
 * @retval     non-zero  PRNG ready to read
 */
__STATIC_INLINE uint16_t PRNG_Ready(void)
{
    return (MXC_PRNG->user_entropy & MXC_F_PRNG_USER_ENTROPY_RND_NUM_READY);
}

/**
 * @brief      Retrieve a seed value from the PRNG.
 * @note       The PRNG hardware does not produce true random numbers. The
 *             output should be used as a seed to an approved random-number
 *             algorithm, per a certifying authority such as NIST or PCI. The
 *             approved algorithm will output random numbers which are cerfitied
 *             for use in encryption and authentication algorithms.
 *
 * @return     16-bit seed value
 */
__STATIC_INLINE uint16_t PRNG_GetSeed(void)
{
    return MXC_PRNG->rnd_num;
}

/**
 * @brief      Add user entropy to the PRNG entropy source.
 *
 * @param      entropy  A value to be mixed into the PRNG entropy source.
 */
__STATIC_INLINE void PRNG_AddUserEntropy(uint8_t entropy)
{
    MXC_PRNG->user_entropy = (uint32_t)entropy;
}
/**@}*/
#ifdef __cplusplus
}
#endif

#endif /* _PRNG_H_ */

