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61 lines
1.2 KiB
C
61 lines
1.2 KiB
C
/*
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* Copyright (C) 2019 Gunar Schorcht
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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_esp8266
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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 Gunar Schorcht <gunar@schorcht.net>
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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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#include "rom/ets_sys.h"
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#ifdef MCU_ESP32
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static const uint32_t* RNG_DATA_REG = (uint32_t*)0x3ff75144;
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#else
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static const uint32_t* RNG_DATA_REG = (uint32_t*)0x3ff20e44;
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#endif
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void hwrng_init(void)
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{
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/* no need for initialization */
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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 = *RNG_DATA_REG;
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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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uint32_t hwrand (void)
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{
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uint32_t _tmp;
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hwrng_read(&_tmp, sizeof(uint32_t));
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return _tmp;
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}
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