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STM32: RNG: Ensure that no more than 1 instance is used 

There is only 1 RNG HW IP and we do not support more than one driver
user at a time, so let's ensure this is the case and raise an error if
needed.
pull/5179/head
Laurent MEUNIER 2017-09-21 10:42:27 +02:00
parent 14343c49c4
commit 849749f86f
1 changed files with 11 additions and 0 deletions
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11
targets/TARGET_STM/trng_api.c
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@ -23,11 +23,20 @@
#include <stdlib.h> #include <stdlib.h>
#include "cmsis.h" #include "cmsis.h"
#include "trng_api.h" #include "trng_api.h"
#include "mbed_error.h"
#include "mbed_critical.h"
static uint8_t users = 0;
void trng_init(trng_t *obj) void trng_init(trng_t *obj)
{ {
uint32_t dummy; uint32_t dummy;
/* We're only supporting a single user of RNG */
if (core_util_atomic_incr_u8(&users, 1) > 1 ) {
error("Only 1 RNG instance supported\r\n");
}
#if defined(TARGET_STM32L4) #if defined(TARGET_STM32L4)
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct; RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
@ -57,6 +66,8 @@ void trng_free(trng_t *obj)
HAL_RNG_DeInit(&obj->handle); HAL_RNG_DeInit(&obj->handle);
/* RNG Peripheral clock disable - assume we're the only users of RNG */ /* RNG Peripheral clock disable - assume we're the only users of RNG */
__HAL_RCC_RNG_CLK_DISABLE(); __HAL_RCC_RNG_CLK_DISABLE();
users = 0;
} }
int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length) int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)