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Merge pull request #4840 from haukepetersen/opt_nrf_hwrng

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cpu/nrf5x: unified hwrng driver
This commit is contained in:
Peter Kietzmann 2016-03-03 11:16:26 +01:00
commit 367d8af649
4 changed files with 34 additions and 70 deletions
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3
cpu/cortexm_common/cortexm_init.c
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@ -49,4 +49,7 @@ void cortexm_init(void)
for (IRQn_Type i = 0; i < (int) CPU_IRQ_NUMOF; i++) { for (IRQn_Type i = 0; i < (int) CPU_IRQ_NUMOF; i++) {
NVIC_SetPriority(i, CPU_DEFAULT_IRQ_PRIO); NVIC_SetPriority(i, CPU_DEFAULT_IRQ_PRIO);
} }
/* enable wake up on events for __WFE CPU sleep */
SCB->SCR |= SCB_SCR_SEVONPEND_Msk;
} }

12
cpu/cortexm_common/include/cpu.h
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@ -102,6 +102,18 @@ static inline void cpu_print_last_instruction(void)
printf("%p\n", (void*) lr_ptr); printf("%p\n", (void*) lr_ptr);
} }
/**
* @brief Put the CPU into the 'wait for event' sleep mode
*
* This function is meant to be used for short periods of time, where it is not
* feasible to switch to the idle thread and back.
*/
static inline void cpu_sleep_until_event(void)
{
__SEV();
__WFE();
}
#ifdef __cplusplus #ifdef __cplusplus
} }
#endif #endif

65
cpu/nrf51/periph/hwrng.c
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@ -1,65 +0,0 @@
/*
* Copyright (C) 2014-2016 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup cpu_nrf51
* @{
*
* @file
* @brief Driver for the NRF51822 random number generator
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Frank Holtz <frank-riot2015@holtznet.de>
*
* @}
*/
#include "cpu.h"
#include "periph/hwrng.h"
void hwrng_init(void)
{
/* The RNG is initiated every time when RNG read is called
* This reduces power consumption when RNG is not needed
*/
}
void hwrng_read(uint8_t *buf, unsigned int num)
{
unsigned int count = 0;
/* power on RNG */
NRF_RNG->POWER = 1;
/* Generate events when RNG is finished */
NRF_RNG->INTENSET = RNG_INTENSET_VALRDY_Msk;
/* Start Task */
NRF_RNG->TASKS_START = 1;
/* NRF51 PAN #21 */
NRF_RNG->EVENTS_VALRDY = 0;
while (count < num) {
/* sleep until number is generated */
while (NRF_RNG->EVENTS_VALRDY == 0) {
/* enable wake up on events for __WFE CPU sleep */
SCB->SCR |= SCB_SCR_SEVONPEND_Msk;
/* sleep until next event */
__SEV();
__WFE();
__WFE();
}
buf[count++] = (uint8_t)NRF_RNG->VALUE;
/* NRF51 PAN #21 */
NRF_RNG->EVENTS_VALRDY = 0;
/* clear interrupt state */
NVIC_ClearPendingIRQ(RNG_IRQn);
}
/* power off RNG */
NRF_RNG->POWER = 0;
}

24
cpu/nrf52/periph/hwrng.c → cpu/nrf5x_common/periph/hwrng.c
View File

@ -1,6 +1,6 @@
/* /*
* Copyright (C) 2015 Jan Wagner <mail@jwagner.eu> * Copyright (C) 2014-2016 Freie Universität Berlin
* 2016 Freie Universität Berlin * 2015 Jan Wagner <mail@jwagner.eu>
* *
* This file is subject to the terms and conditions of the GNU Lesser * This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level * General Public License v2.1. See the file LICENSE in the top level
@ -8,13 +8,14 @@
*/ */
/** /**
* @ingroup cpu_nrf52 * @ingroup cpu_nrf5x_common
* @{ * @{
* *
* @file * @file
* @brief Implementation of the hardware random number generator interface * @brief Implementation of the hardware random number generator interface
* *
* @author Hauke Petersen <hauke.petersen@fu-berlin.de> * @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Frank Holtz <frank-riot2015@holtznet.de>
* @author Jan Wagner <mail@jwagner.eu> * @author Jan Wagner <mail@jwagner.eu>
* *
* @} * @}
@ -32,14 +33,27 @@ void hwrng_read(uint8_t *buf, unsigned int num)
{ {
unsigned int count = 0; unsigned int count = 0;
/* power on RNG */
#ifdef CPU_FAM_NRF51
NRF_RNG->POWER = 1;
#endif
NRF_RNG->TASKS_START = 1; NRF_RNG->TASKS_START = 1;
/* read the actual random data */
while (count < num) { while (count < num) {
while (NRF_RNG->EVENTS_VALRDY == 0); /* sleep until number is generated */
while (NRF_RNG->EVENTS_VALRDY == 0) {
cpu_sleep_until_event();
}
NRF_RNG->EVENTS_VALRDY = 0;
buf[count++] = (uint8_t)NRF_RNG->VALUE; buf[count++] = (uint8_t)NRF_RNG->VALUE;
/* NRF51 PAN #21 -> read value before clearing VALRDY */
NRF_RNG->EVENTS_VALRDY = 0;
} }
/* power off RNG */
NRF_RNG->TASKS_STOP = 1; NRF_RNG->TASKS_STOP = 1;
#ifdef CPU_FAM_NRF51
NRF_RNG->POWER = 0;
#endif
} }