mirror of https://github.com/ARMmbed/mbed-os.git
101 lines
2.8 KiB
C
101 lines
2.8 KiB
C
/*
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* Hardware entropy collector for the STM32 families
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*
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* Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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#if defined(DEVICE_TRNG)
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#include <stdlib.h>
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#include "cmsis.h"
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#include "trng_api.h"
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#include "mbed_error.h"
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#include "mbed_critical.h"
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static uint8_t users = 0;
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void trng_init(trng_t *obj)
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{
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uint32_t dummy;
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/* We're only supporting a single user of RNG */
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if (core_util_atomic_incr_u8(&users, 1) > 1) {
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error("Only 1 RNG instance supported\r\n");
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}
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#if defined(TARGET_STM32L4)
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RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
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/*Select PLLQ output as RNG clock source */
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PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RNG;
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PeriphClkInitStruct.RngClockSelection = RCC_RNGCLKSOURCE_PLL;
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HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
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#endif
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/* RNG Peripheral clock enable */
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__HAL_RCC_RNG_CLK_ENABLE();
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/* Initialize RNG instance */
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obj->handle.Instance = RNG;
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obj->handle.State = HAL_RNG_STATE_RESET;
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obj->handle.Lock = HAL_UNLOCKED;
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HAL_RNG_Init(&obj->handle);
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/* first random number generated after setting the RNGEN bit should not be used */
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HAL_RNG_GenerateRandomNumber(&obj->handle, &dummy);
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}
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void trng_free(trng_t *obj)
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{
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/*Disable the RNG peripheral */
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HAL_RNG_DeInit(&obj->handle);
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/* RNG Peripheral clock disable - assume we're the only users of RNG */
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__HAL_RCC_RNG_CLK_DISABLE();
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users = 0;
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}
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int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
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{
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int ret = 0;
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volatile uint8_t random[4];
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*output_length = 0;
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/* Get Random byte */
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while ((*output_length < length) && (ret == 0)) {
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if (HAL_RNG_GenerateRandomNumber(&obj->handle, (uint32_t *)random) != HAL_OK) {
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ret = -1;
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} else {
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for (uint8_t i = 0; (i < 4) && (*output_length < length) ; i++) {
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*output++ = random[i];
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*output_length += 1;
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random[i] = 0;
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}
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}
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}
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/* Just be extra sure that we didn't do it wrong */
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if ((__HAL_RNG_GET_FLAG(&obj->handle, (RNG_FLAG_CECS | RNG_FLAG_SECS))) != 0) {
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ret = -1;
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}
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return (ret);
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}
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#endif
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