riot-ci/RIOT
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

cpu/sam3: adapted HWRNG implementation

Browse Source
This commit is contained in:
Hauke Petersen 2016-02-05 16:46:24 +01:00
parent 6f0179ce69
commit 79cf50db03
1 changed files with 16 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
cpu/sam3/periph/random.c → cpu/sam3/periph/hwrng.c
View File

@ -1,13 +1,13 @@
/* /*
* Copyright (C) 2014 Freie Universität Berlin * Copyright (C) 2014-2016 Freie Universität Berlin
* *
* This file is subject to the terms and conditions of the GNU Lesser General * This file is subject to the terms and conditions of the GNU Lesser
* Public License v2.1. See the file LICENSE in the top level directory for more * General Public License v2.1. See the file LICENSE in the top level
* details. * directory for more details.
*/ */
/** /**
* @ingroup driver_periph * @ingroup cpu_sam3
* @{ * @{
* *
* @file * @file
@ -19,11 +19,7 @@
*/ */
#include "cpu.h" #include "cpu.h"
#include "periph_conf.h" #include "periph/hwrng.h"
#include "periph/random.h"
/* only compile this driver if enabled in the board's periph_conf.h */
#if RANDOM_NUMOF
/** /**
* @name KEY needs to be written to the config register when en|disabling * @name KEY needs to be written to the config register when en|disabling
@ -31,46 +27,34 @@
*/ */
#define KEY (0x524e4700) #define KEY (0x524e4700)
void random_init(void) void hwrng_init(void)
{ {
random_poweron(); /* no need for initialization */
} }
int random_read(char *buf, unsigned int num) void hwrng_read(uint8_t *buf, unsigned int num)
{ {
/* cppcheck-suppress variableScope */
uint32_t tmp;
unsigned count = 0; unsigned count = 0;
/* enable clock signal for TRNG module */
PMC->PMC_PCER1 |= PMC_PCER1_PID41;
/* enable the generation of random numbers */
TRNG->TRNG_CR |= (KEY | TRNG_CR_ENABLE);
while (count < num) { while (count < num) {
/* wait until new value is generated -> takes up to 84 cycles */ /* wait until new value is generated -> takes up to 84 cycles */
while (!(TRNG->TRNG_ISR & TRNG_ISR_DATRDY)); while (!(TRNG->TRNG_ISR & TRNG_ISR_DATRDY));
/* read 4 byte of random data */ /* read 4 byte of random data */
tmp = TRNG->TRNG_ODATA; uint32_t tmp = TRNG->TRNG_ODATA;
/* extract copy bytes to result */ /* extract copy bytes to result */
for (int i = 0; i < 4 && count < num; i++) { for (int i = 0; i < 4 && count < num; i++) {
buf[count++] = (char)tmp; buf[count++] = (uint8_t)tmp;
tmp = tmp >> 8; tmp = tmp >> 8;
} }
} }
return count;
}
void random_poweron(void)
{
/* enable clock signal for TRNG module */
PMC->PMC_PCER1 |= PMC_PCER1_PID41;
/* enable the generation of random numbers */
TRNG->TRNG_CR |= (KEY | TRNG_CR_ENABLE);
}
void random_poweroff(void)
{
/* disable the generation of random numbers */ /* disable the generation of random numbers */
TRNG->TRNG_CR &= ~(KEY | TRNG_CR_ENABLE); TRNG->TRNG_CR &= ~(KEY | TRNG_CR_ENABLE);
/* disable clock signal for TRNG module */ /* disable clock signal for TRNG module */
PMC->PMC_PCER1 &= ~(PMC_PCER1_PID41); PMC->PMC_PCER1 &= ~(PMC_PCER1_PID41);
} }
#endif /* RANDOM_NUMOF */