mcxn547_crypto_trng.c

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/**
 * @file mcxn547_crypto_trng.c
 * @brief NXP MCX N547 true random number generator
 *
 * @section License
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * Copyright (C) 2010-2025 Oryx Embedded SARL. All rights reserved.
 *
 * This file is part of CycloneCRYPTO Open.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * @author Oryx Embedded SARL (www.oryx-embedded.com)
 * @version 2.5.4
 **/
 
//Switch to the appropriate trace level
#define TRACE_LEVEL CRYPTO_TRACE_LEVEL
 
//Dependencies
#include <mcuxClEls.h>
#include <internal/mcuxClTrng_Internal.h>
#include "core/crypto.h"
#include "hardware/mcxn547/mcxn547_crypto.h"
#include "hardware/mcxn547/mcxn547_crypto_trng.h"
#include "debug.h"
 
//Global variables
static uint32_t buffer[MCUXCLTRNG_ELS_TRNG_OUTPUT_SIZE / 4];
static size_t bufferPos;
 
//Check crypto library configuration
#if (MCXN547_CRYPTO_TRNG_SUPPORT == ENABLED)
 
 
/**
 * @brief TRNG module initialization
 * @return Error code
 **/
 
error_t trngInit(void)
{
   error_t error;
 
   //Initialize status code
   error = NO_ERROR;
 
   //Mark the buffer as empty
   bufferPos = MCUXCLTRNG_ELS_TRNG_OUTPUT_SIZE;
 
   //Initialize TRNG
   MCUX_CSSL_FP_FUNCTION_CALL_BEGIN(status, token, mcuxClTrng_Init());
 
   //Check the protection token and the return value
   if(token != MCUX_CSSL_FP_FUNCTION_CALLED(mcuxClTrng_Init) ||
      status != MCUXCLTRNG_STATUS_OK)
   {
      error = ERROR_FAILURE;
   }
 
   //End of function call
   MCUX_CSSL_FP_FUNCTION_CALL_END();
 
   //Return status code
   return error;
}
 
 
/**
 * @brief Get random data from the TRNG module
 * @param[out] data Buffer where to store random data
 * @param[in] length Number of random bytes to generate
 **/
 
error_t trngGetRandomData(uint8_t *data, size_t length)
{
   error_t error;
   size_t i;
   uint32_t temp;
 
   //Initialize status code
   error = NO_ERROR;
 
   //Acquire exclusive access to the ELS module
   osAcquireMutex(&mcxn547CryptoMutex);
 
   //Generate random data
   for(i = 0; i < length && !error; i++)
   {
      //Generate a new 32-byte random value when necessary
      if(bufferPos >= MCUXCLTRNG_ELS_TRNG_OUTPUT_SIZE)
      {
         //Generate random bytes
         MCUX_CSSL_FP_FUNCTION_CALL_BEGIN(status, token, mcuxClTrng_getEntropyInput(
            &elsSession, buffer, MCUXCLTRNG_ELS_TRNG_OUTPUT_SIZE));
 
         //Check the protection token and the return value
         if(token != MCUX_CSSL_FP_FUNCTION_CALLED(mcuxClTrng_getEntropyInput) ||
            status != MCUXCLTRNG_STATUS_OK)
         {
            error = ERROR_FAILURE;
         }
 
         //End of function call
         MCUX_CSSL_FP_FUNCTION_CALL_END();
 
         //Rewind to the beginning of the buffer
         bufferPos = 0;
      }
 
      //Extract a random byte
      data[i] = (buffer[bufferPos / 4] >> ((bufferPos % 4) * 8)) & 0xFF;
      //Increment index
      bufferPos++;
   }
 
   //Release exclusive access to the ELS module
   osReleaseMutex(&mcxn547CryptoMutex);
 
   //Return status code
   return error;
}
 
#endif