mirror of https://github.com/ARMmbed/mbed-os.git
113 lines
4.2 KiB
C
113 lines
4.2 KiB
C
/**
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******************************************************************************
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* @file trng_api.c
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* @brief Implementation of TRNG functionality.
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* @internal
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* @author ON Semiconductor.
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* $Rev: $
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* $Date: $
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******************************************************************************
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* Copyright 2016 Semiconductor Components Industries LLC (d/b/a “ON Semiconductor”).
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* All rights reserved. This software and/or documentation is licensed by ON Semiconductor
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* under limited terms and conditions. The terms and conditions pertaining to the software
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* and/or documentation are available at http://www.onsemi.com/site/pdf/ONSEMI_T&C.pdf
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* (“ON Semiconductor Standard Terms and Conditions of Sale, Section 8 Software”) and
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* if applicable the software license agreement. Do not use this software and/or
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* documentation unless you have carefully read and you agree to the limited terms and
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* conditions. By using this software and/or documentation, you agree to the limited
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* terms and conditions.
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*
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* THIS SOFTWARE IS PROVIDED "AS IS". NO WARRANTIES, WHETHER EXPRESS, IMPLIED
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* OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
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* ON SEMICONDUCTOR SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL,
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* INCIDENTAL, OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
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* @endinternal
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*
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* @ingroup TRNG
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*
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*/
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#if DEVICE_TRNG
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/*************************************************************************************************
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* *
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* Header files *
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* *
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*************************************************************************************************/
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#include "trng_api.h"
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#include "memory_map.h"
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#include "ncs36510_trng.h"
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#include "clock.h"
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/*************************************************************************************************
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* *
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* Functions *
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* *
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*************************************************************************************************/
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void trng_init(trng_t *obj)
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{
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/* Enable TRNG */
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CLOCK_ENABLE(CLOCK_RAND);
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/* Initialize TRNG */
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RANDREG->CONTROL.WORD = False;
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return;
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}
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void trng_free(trng_t *obj)
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{
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/* Stop TRNG */
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RANDREG->CONTROL.WORD = False;
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/* Disable TRNG */
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CLOCK_DISABLE(CLOCK_RAND);
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return;
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}
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int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
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{
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uint32_t MSLRandom = 0, Index, TempLen, *TempPtr = (uint32_t*)output;
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volatile uint32_t delay;
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RANDREG->CONTROL.BITS.METASTABLE_LATCH_EN = TRNG_ENABLE; /* ENable MSL TRNG */
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RANDREG->CONTROL.BITS.MEATSTABLE_SPEED = TRNG_FAST_MODE; /* Meta-stable Latch TRNG Speed Control */
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RANDREG->CONTROL.BITS.MODE = TRNG_ON_READ_EVENT; /* TRNG is only updated on a read event of the TRNG register */
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for(uint32_t delay = 0;delay < 0x1F; delay++); /* Wait till generate MSL TRNG after enable for the first time */
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TempLen = length / 4;
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for(Index = 0; Index < TempLen; Index++)
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{
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MSLRandom = RANDREG->METASTABLE_LATCH_VAL;
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*TempPtr++ = MSLRandom ;
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}
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TempLen = length % 4;
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Index *= 4;
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if(TempLen-- > 0)
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{
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MSLRandom = RANDREG->METASTABLE_LATCH_VAL;
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*(output + Index++) = (MSLRandom >> 0) & 0xFF;
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if(TempLen-- > 0)
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{
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*(output + Index++) = (MSLRandom >> 8) & 0xFF;
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if(TempLen-- > 0)
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{
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*(output + Index++) = (MSLRandom >> 16) & 0xFF;
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}
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}
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}
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RANDREG->CONTROL.BITS.METASTABLE_LATCH_EN = TRNG_DISABLE; /* Disable MSL */
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*output_length = Index;
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return 0; /* Success */
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}
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#endif /* DEVICE_TRNG */ |