mirror of https://github.com/ARMmbed/mbed-os.git
113 lines
4.1 KiB
C
113 lines
4.1 KiB
C
/**
|
|
******************************************************************************
|
|
* @file trng_api.c
|
|
* @brief Implementation of TRNG functionality.
|
|
* @internal
|
|
* @author ON Semiconductor.
|
|
* $Rev: $
|
|
* $Date: $
|
|
******************************************************************************
|
|
* Copyright 2016 Semiconductor Components Industries LLC (d/b/a “ON Semiconductor”).
|
|
* All rights reserved. This software and/or documentation is licensed by ON Semiconductor
|
|
* under limited terms and conditions. The terms and conditions pertaining to the software
|
|
* and/or documentation are available at http://www.onsemi.com/site/pdf/ONSEMI_T&C.pdf
|
|
* (“ON Semiconductor Standard Terms and Conditions of Sale, Section 8 Software”) and
|
|
* if applicable the software license agreement. Do not use this software and/or
|
|
* documentation unless you have carefully read and you agree to the limited terms and
|
|
* conditions. By using this software and/or documentation, you agree to the limited
|
|
* terms and conditions.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED "AS IS". NO WARRANTIES, WHETHER EXPRESS, IMPLIED
|
|
* OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
|
|
* ON SEMICONDUCTOR SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL,
|
|
* INCIDENTAL, OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
|
|
* @endinternal
|
|
*
|
|
* @ingroup TRNG
|
|
*
|
|
*/
|
|
#if DEVICE_TRNG
|
|
|
|
/*************************************************************************************************
|
|
* *
|
|
* Header files *
|
|
* *
|
|
*************************************************************************************************/
|
|
#include "trng_api.h"
|
|
#include "memory_map.h"
|
|
#include "ncs36510_trng.h"
|
|
#include "clock.h"
|
|
#include "mbed_wait_api.h"
|
|
|
|
/*************************************************************************************************
|
|
* *
|
|
* Functions *
|
|
* *
|
|
*************************************************************************************************/
|
|
|
|
|
|
void trng_init(trng_t *obj)
|
|
{
|
|
/* Enable TRNG */
|
|
CLOCK_ENABLE(CLOCK_RAND);
|
|
|
|
/* Initialize TRNG */
|
|
RANDREG->CONTROL.WORD = False;
|
|
|
|
return;
|
|
}
|
|
void trng_free(trng_t *obj)
|
|
{
|
|
/* Stop TRNG */
|
|
RANDREG->CONTROL.WORD = False;
|
|
|
|
/* Disable TRNG */
|
|
CLOCK_DISABLE(CLOCK_RAND);
|
|
|
|
return;
|
|
}
|
|
|
|
int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
|
|
{
|
|
uint32_t MSLRandom = 0, Index, TempLen, *TempPtr = (uint32_t*)output;
|
|
|
|
RANDREG->CONTROL.BITS.METASTABLE_LATCH_EN = TRNG_ENABLE; /* ENable MSL TRNG */
|
|
RANDREG->CONTROL.BITS.MEATSTABLE_SPEED = TRNG_FAST_MODE; /* Meta-stable Latch TRNG Speed Control */
|
|
RANDREG->CONTROL.BITS.MODE = TRNG_ON_READ_EVENT; /* TRNG is only updated on a read event of the TRNG register */
|
|
|
|
wait_us(1); /* Wait till MSL generates random number after enable for the first time */
|
|
|
|
TempLen = length / 4;
|
|
|
|
for(Index = 0; Index < TempLen; Index++)
|
|
{
|
|
MSLRandom = RANDREG->METASTABLE_LATCH_VAL;
|
|
*TempPtr++ = MSLRandom ;
|
|
}
|
|
|
|
TempLen = length % 4;
|
|
Index *= 4;
|
|
|
|
if(TempLen-- > 0)
|
|
{
|
|
MSLRandom = RANDREG->METASTABLE_LATCH_VAL;
|
|
*(output + Index++) = (MSLRandom >> 0) & 0xFF;
|
|
if(TempLen-- > 0)
|
|
{
|
|
*(output + Index++) = (MSLRandom >> 8) & 0xFF;
|
|
if(TempLen-- > 0)
|
|
{
|
|
*(output + Index++) = (MSLRandom >> 16) & 0xFF;
|
|
}
|
|
}
|
|
}
|
|
|
|
RANDREG->CONTROL.BITS.METASTABLE_LATCH_EN = TRNG_DISABLE; /* Disable MSL */
|
|
|
|
*output_length = Index;
|
|
|
|
return 0; /* Success */
|
|
}
|
|
|
|
#endif /* DEVICE_TRNG */ |