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stm32f2: Update hwrng driver

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This commit is contained in:
Aurelien Gonce 2016-04-13 15:47:12 +02:00
parent 182be862bb
commit d01da278ac
1 changed files with 14 additions and 4 deletions
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18
cpu/stm32f2/periph/hwrng.c
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@ -1,5 +1,6 @@
/*
* Copyright (C) 2014 Freie Universität Berlin
* Copyright (C) 2016 OTA keys S.A.
*
* 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
@ -14,6 +15,7 @@
* @brief Low-level random number generator driver implementation
*
* @author Hauke Petersen <mail@haukepetersen.de>
* @author Aurelien Gonce <aurelien.gonce@altran.fr>
*
* @}
*/
@ -27,17 +29,23 @@
void hwrng_init(void)
{
/* enable RNG reset state */
RCC->AHB2ENR |= RCC_AHB2ENR_RNGEN;
/* release RNG from reset state */
RCC->AHB2ENR &= ~RCC_AHB2ENR_RNGEN;
}
void hwrng_read(uint8_t *buf, unsigned int num)
{
/* cppcheck-suppress variableScope */
uint32_t tmp;
unsigned int count = 0;
/* enable RNG reset state */
RCC->AHB2ENR |= RCC_AHB2ENR_RNGEN;
RNG->CR = RNG_CR_RNGEN;
/* enable the RNG */
RNG->CR |= RNG_CR_RNGEN;
while (count < num) {
/* wait for random data to be ready to read */
@ -46,12 +54,14 @@ void hwrng_read(uint8_t *buf, unsigned int num)
tmp = RNG->DR;
/* copy data into result vector */
for (int i = 0; i < 4 && count < num; i++) {
buf[count++] = (char)tmp;
buf[count++] = (uint8_t)tmp;
tmp = tmp >> 8;
}
}
RNG->CR = 0;
/* disable the RNG */
RNG->CR &= ~RNG_CR_RNGEN;
/* release RNG from reset state */
RCC->AHB2ENR &= ~RCC_AHB2ENR_RNGEN;
}