mirror of https://github.com/ARMmbed/mbed-os.git
89 lines
2.4 KiB
C
89 lines
2.4 KiB
C
/*
|
|
* Hardware entropy collector for the STM32 families
|
|
*
|
|
* Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License"); you may
|
|
* not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*
|
|
*/
|
|
|
|
#if defined(DEVICE_TRNG)
|
|
|
|
#include <stdlib.h>
|
|
#include "cmsis.h"
|
|
#include "trng_api.h"
|
|
|
|
/** trng_get_byte
|
|
* @brief Get one byte of entropy from the RNG, assuming it is up and running.
|
|
* @param obj TRNG obj
|
|
* @param pointer to the hardware generated random byte.
|
|
*/
|
|
static void trng_get_byte(trng_t *obj, unsigned char *byte )
|
|
{
|
|
*byte = (unsigned char)HAL_RNG_GetRandomNumber(&obj->handle);
|
|
}
|
|
|
|
void trng_init(trng_t *obj)
|
|
{
|
|
#if defined(TARGET_STM32L4)
|
|
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
|
|
|
|
/*Select PLLQ output as RNG clock source */
|
|
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RNG;
|
|
PeriphClkInitStruct.RngClockSelection = RCC_RNGCLKSOURCE_PLL;
|
|
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
|
|
#endif
|
|
|
|
/* RNG Peripheral clock enable */
|
|
__HAL_RCC_RNG_CLK_ENABLE();
|
|
|
|
/* Initialize RNG instance */
|
|
obj->handle.Instance = RNG;
|
|
HAL_RNG_Init(&obj->handle);
|
|
|
|
/* first random number generated after setting the RNGEN bit should not be used */
|
|
HAL_RNG_GetRandomNumber(&obj->handle);
|
|
|
|
}
|
|
|
|
void trng_free(trng_t *obj)
|
|
{
|
|
/*Disable the RNG peripheral */
|
|
HAL_RNG_DeInit(&obj->handle);
|
|
/* RNG Peripheral clock disable - assume we're the only users of RNG */
|
|
__HAL_RCC_RNG_CLK_DISABLE();
|
|
}
|
|
|
|
int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
|
|
{
|
|
int ret;
|
|
|
|
/* Get Random byte */
|
|
for( uint32_t i = 0; i < length; i++ ){
|
|
trng_get_byte(obj, output + i );
|
|
}
|
|
|
|
*output_length = length;
|
|
/* Just be extra sure that we didn't do it wrong */
|
|
if( ( __HAL_RNG_GET_FLAG(&obj->handle, (RNG_FLAG_CECS | RNG_FLAG_SECS)) ) != 0 ) {
|
|
ret = -1;
|
|
} else {
|
|
ret = 0;
|
|
}
|
|
|
|
return( ret );
|
|
}
|
|
|
|
#endif
|