mirror of https://github.com/ARMmbed/mbed-os.git
88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
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/* mbed Microcontroller Library
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* Copyright (c) 2018 GigaDevice Semiconductor Inc.
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*
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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");
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* you may 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,
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* WITHOUT 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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#if DEVICE_TRNG
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#include "trng_api.h"
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/** Initialize the TRNG peripheral
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*
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* @param obj The TRNG object
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*/
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void trng_init(trng_t *obj)
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{
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(void)obj;
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/* TRNG module clock enable */
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rcu_periph_clock_enable(RCU_TRNG);
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/* TRNG registers reset */
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trng_deinit();
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trng_enable();
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}
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/** Deinitialize the TRNG peripheral
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*
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* @param obj The TRNG object
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*/
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void trng_free(trng_t *obj)
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{
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(void)obj;
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trng_disable();
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}
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/** Get random data from TRNG peripheral
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*
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* @param obj The TRNG object
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* @param output The pointer to an output array
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* @param length The size of output data, to avoid buffer overwrite
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* @param output_length The length of generated data
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* @return 0 success, -1 fail
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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 reval = 0;
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volatile uint8_t tmp[4];
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uint32_t timeout = 0;
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(void)obj;
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*output_length = 0;
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while ((*output_length < length) && (0 == reval)) {
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while (0 == trng_flag_get(TRNG_FLAG_DRDY) && timeout < 0x1FFFF) {
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timeout++;
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}
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if (timeout == 0x1FFFF) {
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reval = -1;
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break;
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}
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*(uint32_t *)tmp = trng_get_true_random_data();
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for (uint8_t i = 0; (i < 4) && (*output_length < length) ; i++) {
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*output++ = tmp[i];
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*output_length += 1;
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tmp[i] = 0;
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}
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}
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/* Determines the status error current and error current */
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if ((1 == trng_flag_get(TRNG_FLAG_CECS)) || (1 == trng_flag_get(TRNG_FLAG_SECS))) {
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reval = -1;
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}
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return reval;
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}
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#endif /* DEVICE_TRNG */
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