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STM32: TRNG: remove call to deprecated HAL_RNG_GetRandomNumber 

HAL_RNG_GetRandomNumber is a deprecated API and replaced here with
a call to HAL_RNG_GenerateRandomNumber.

Doing so, we also rework the driver to use the 4 bytes returned by a call
to HAL_RNG_GenerateRandomNumber instead of 1 byte out of 4.

HAL_RNG_GenerateRandomNumber was not returning any error code, so now
we can also check the return code.
pull/5427/head
Laurent MEUNIER 2017-09-21 10:42:27 +02:00 committed by Martin Kojtal
parent 16048c261f
commit a375ea0619
1 changed files with 18 additions and 17 deletions
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35
targets/TARGET_STM/trng_api.c
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@ -24,18 +24,10 @@
#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)
{
uint32_t dummy;
#if defined(TARGET_STM32L4)
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
@ -50,11 +42,13 @@ void trng_init(trng_t *obj)
/* Initialize RNG instance */
obj->handle.Instance = RNG;
obj->handle.State = HAL_RNG_STATE_RESET;
obj->handle.Lock = HAL_UNLOCKED;
HAL_RNG_Init(&obj->handle);
/* first random number generated after setting the RNGEN bit should not be used */
HAL_RNG_GetRandomNumber(&obj->handle);
HAL_RNG_GenerateRandomNumber(&obj->handle, &dummy);
}
void trng_free(trng_t *obj)
@ -67,19 +61,26 @@ void trng_free(trng_t *obj)
int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
{
int ret;
int ret = 0;
volatile uint8_t random[4];
*output_length = 0;
/* Get Random byte */
for( uint32_t i = 0; i < length; i++ ){
trng_get_byte(obj, output + i );
while ((*output_length < length) && (ret ==0)) {
if ( HAL_RNG_GenerateRandomNumber(&obj->handle, (uint32_t *)random ) != HAL_OK) {
ret = -1;
} else {
for (uint8_t i =0; (i < 4) && (*output_length < length) ; i++) {
*output++ = random[i];
*output_length += 1;
random[i] = 0;
}
}
}
*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 );