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58 lines
1.2 KiB
C
58 lines
1.2 KiB
C
/*
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* Copyright (C) 2019 ML!PA Consulting GmbH
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup cpu_sam0_common
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* @ingroup drivers_periph_hwrng
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* @{
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*
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* @file
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* @brief Low-level random number generator driver implementation
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*
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* @author Benjamin Valentin <benjamin.valentin@ml-pa.com>
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*
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* @}
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*/
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#include "cpu.h"
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#include "periph_conf.h"
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#include "periph/hwrng.h"
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void hwrng_init(void)
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{
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/* Enable the MCLK */
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MCLK->APBCMASK.reg |= MCLK_APBCMASK_TRNG;
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/* Enable the TRNG */
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TRNG->CTRLA.reg |= TRNG_CTRLA_ENABLE;
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}
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uint32_t hwrand(void)
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{
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while (!(TRNG->INTFLAG.reg & TRNG_INTFLAG_DATARDY)) {}
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return TRNG->DATA.reg;
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}
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void hwrng_read(void *buf, unsigned int num)
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{
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unsigned int count = 0;
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uint8_t *b = (uint8_t *)buf;
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while (count < num) {
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/* read next 4 bytes of random data */
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uint32_t tmp = hwrand();
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/* copy data into result vector */
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for (int i = 0; i < 4 && count < num; i++) {
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b[count++] = (uint8_t)tmp;
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tmp = tmp >> 8;
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}
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}
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}
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