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94 lines
2.3 KiB
C
94 lines
2.3 KiB
C
/*
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* Copyright (C) 2014-2016 Freie Universität Berlin
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* 2015 Jan Wagner <mail@jwagner.eu>
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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_nrf5x_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 Implementation of the hardware random number generator interface
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*
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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* @author Frank Holtz <frank-riot2015@holtznet.de>
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* @author Jan Wagner <mail@jwagner.eu>
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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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#ifndef MODULE_NORDIC_SOFTDEVICE_BLE
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#include "assert.h"
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#endif
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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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/*
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* The hardware peripheral is used by the SoftDevice. When the SoftDevice is
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* enabled, it shall only be accessed through the SoftDevice API
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*/
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#ifndef MODULE_NORDIC_SOFTDEVICE_BLE
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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 RNG */
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#ifdef CPU_FAM_NRF51
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NRF_RNG->POWER = 1;
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#endif
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NRF_RNG->INTENSET = RNG_INTENSET_VALRDY_Msk;
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NRF_RNG->TASKS_START = 1;
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/* read the actual random data */
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while (count < num) {
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/* sleep until number is generated */
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while (NRF_RNG->EVENTS_VALRDY == 0) {
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cortexm_sleep_until_event();
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}
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b[count++] = (uint8_t)NRF_RNG->VALUE;
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/* NRF51 PAN #21 -> read value before clearing VALRDY */
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NRF_RNG->EVENTS_VALRDY = 0;
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NVIC_ClearPendingIRQ(RNG_IRQn);
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}
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/* power off RNG */
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NRF_RNG->INTENCLR = RNG_INTENSET_VALRDY_Msk;
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NRF_RNG->TASKS_STOP = 1;
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#ifdef CPU_FAM_NRF51
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NRF_RNG->POWER = 0;
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#endif
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}
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#else
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void hwrng_read(void *buf, unsigned int num)
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{
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uint32_t ret;
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uint8_t avail;
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assert(num <= 0xff);
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/* this is not the most efficient, but this way we can assure that there are
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* enough bytes of random data available */
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do {
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sd_rand_application_bytes_available_get(&avail);
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} while (avail < (uint8_t)num);
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ret = sd_rand_application_vector_get((uint8_t *)buf, (uint8_t)num);
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assert(ret == NRF_SUCCESS);
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(void)ret;
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}
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#endif /* MODULE_NORDIC_SOFTDEVICE_BLE */
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