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65 lines
1.5 KiB
C
65 lines
1.5 KiB
C
/*
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* Copyright (C) 2017 Bas Stottelaar <basstottelaar@gmail.com>
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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_efm32
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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 I2C driver implementation
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*
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* @author Bas Stottelaar <basstottelaar@gmail.com>
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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 "em_cmu.h"
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#include <string.h>
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void hwrng_init(void)
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{
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/* enable clocks */
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CMU_ClockEnable(cmuClock_HFPER, true);
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CMU_ClockEnable(cmuClock_TRNG0, true);
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/* reset and initialize peripheral */
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TRNG0->CONTROL = TRNG_CONTROL_ENABLE |
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TRNG_CONTROL_REPCOUNTIEN |
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TRNG_CONTROL_APT64IEN |
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TRNG_CONTROL_APT4096IEN |
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TRNG_CONTROL_PREIEN |
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TRNG_CONTROL_ALMIEN;
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/* wait for TRNG to become available */
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while (TRNG0->FIFOLEVEL == 0) {}
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}
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void hwrng_read(void *buf, unsigned int num)
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{
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uint32_t *out_buf = (uint32_t *) buf;
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uint32_t tmp;
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/* read known good available data */
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while (num >= 4) {
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*out_buf++ = TRNG0->FIFO;
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num -= 4;
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}
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/* read remaining data (not multiple of 4) */
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if (num) {
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tmp = TRNG0->FIFO;
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memcpy((uint8_t *)out_buf, (const uint8_t *) &tmp, num);
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}
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}
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