mbed-os/targets/TARGET_Cypress/TARGET_PSOC6/trng_api.c

77 lines
2.1 KiB
C

/* mbed Microcontroller Library
* Copyright (c) 2019 Cypress Semiconductor Corporation
* 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.
*/
/* Hardware entropy collector for the PSoC6A families */
#if DEVICE_TRNG
#if !(defined(TARGET_PSA) && defined(COMPONENT_NSPE))
#include "trng_api.h"
#include "psoc6_utils.h"
#include "cy_crypto_core_trng.h"
/* Initialization polynomial values fro True Random Generator */
#define GARO31_INITSTATE (0x04c11db7UL)
#define FIRO31_INITSTATE (0x04c11db7UL)
#define MAX_TRNG_BIT_SIZE (32UL)
void trng_init(trng_t *obj)
{
(void)obj;
cy_reserve_crypto(CY_CRYPTO_TRNG_HW);
}
void trng_free(trng_t *obj)
{
/* Deinitialization is not needed for the driver */
(void)obj;
cy_free_crypto(CY_CRYPTO_TRNG_HW);
}
int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
{
int ret = 0;
*output_length = 0U;
/* temporary random data buffer */
uint32_t random;
(void)obj;
/* Get Random byte */
while ((*output_length < length) && (ret == 0)) {
if (Cy_Crypto_Core_Trng(CRYPTO, GARO31_INITSTATE, FIRO31_INITSTATE, MAX_TRNG_BIT_SIZE, &random) != CY_CRYPTO_SUCCESS) {
ret = -1;
} else {
for (uint8_t i = 0; (i < 4U) && (*output_length < length) ; i++) {
*output++ = ((uint8_t *)&random)[i];
*output_length += 1U;
}
}
}
random = 0UL;
return (ret);
}
#endif // #if !(defined(TARGET_PSA) && defined(COMPONENT_NSPE))
#endif