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70 lines
1.6 KiB
C
70 lines
1.6 KiB
C
/*
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* Copyright (C) 2014-2016 Freie Universität Berlin
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* Copyright (C) 2014 PHYTEC Messtechnik 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_kinetis
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* @ingroup drivers_periph_hwrng
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*
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* @{
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*
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* @file
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* @brief HWRNG interface implementation
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*
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* @author Johann Fischer <j.fischer@phytec.de> (adaption for Freescale's RNGA)
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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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/hwrng.h"
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#include "periph_conf.h"
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#include "bit.h"
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#ifdef KINETIS_RNGA
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void hwrng_init(void)
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{
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/* nothing to do here */
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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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/* power on and enable the device */
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HWRNG_CLKEN();
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KINETIS_RNGA->CR = RNG_CR_INTM_MASK | RNG_CR_HA_MASK | RNG_CR_GO_MASK;
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/* self-seeding */
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while (!(KINETIS_RNGA->SR & RNG_SR_OREG_LVL_MASK));
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KINETIS_RNGA->ER = KINETIS_RNGA->OR ^ (uint32_t)buf;
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while (count < num) {
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/* wait for random data to be ready to read */
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while (!(KINETIS_RNGA->SR & RNG_SR_OREG_LVL_MASK));
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uint32_t tmp = KINETIS_RNGA->OR;
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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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/* power off the device */
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KINETIS_RNGA->CR = 0;
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HWRNG_CLKDIS();
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}
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#endif /* KINETIS_RNGA */
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