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72 lines
1.7 KiB
C
72 lines
1.7 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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* Copyright (C) 2015 Eistec AB
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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_common_rngb
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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 Joakim Nohlgård <joakim.nohlgard@eistec.se> (adaption for Freescale's RNGB)
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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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#ifdef KINETIS_RNGB
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void hwrng_init(void)
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{
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/* nothing to be done here */
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}
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void hwrng_read(uint8_t *buf, unsigned int num)
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{
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unsigned int count = 0;
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HWRNG_CLKEN();
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if ((KINETIS_RNGB->VER & RNG_VER_TYPE_MASK) != 0b0001) {
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/* Wrong type of RNG */
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/* TODO: Handle */
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}
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/* Software reset, bit is self-clearing */
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BITBAND_REG32(KINETIS_RNGB->CMD, RNG_CMD_SR_SHIFT) = 1;
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/* Set up automatic reseed */
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KINETIS_RNGB->CR = RNG_CR_AR_MASK | RNG_CR_MASKERR_MASK | RNG_CR_MASKDONE_MASK;
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while (count < num) {
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uint32_t tmp;
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/* wait for random data to be ready to read */
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while (!(KINETIS_RNGB->SR & RNG_SR_FIFO_LVL_MASK));
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tmp = KINETIS_RNGB->OUT;
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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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buf[count++] = (uint8_t)tmp;
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tmp = tmp >> 8;
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}
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}
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KINETIS_RNGB->CR = 0;
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HWRNG_CLKDIS();
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}
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#endif /* KINETIS_RNGB */
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