mirror of https://github.com/ARMmbed/mbed-os.git
72 lines
2.1 KiB
C
72 lines
2.1 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2019, Arm Limited and affiliates.
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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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#include "trng_api.h"
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#include "cyhal_trng.h"
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#include "mbed_error.h"
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#include <string.h>
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#if DEVICE_TRNG
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#ifdef __cplusplus
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extern "C" {
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#endif
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void trng_init(trng_t *obj)
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{
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if (CY_RSLT_SUCCESS != cyhal_trng_init(&(obj->trng))) {
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MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_DRIVER, MBED_ERROR_CODE_FAILED_OPERATION), "cyhal_trng_init");
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}
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}
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void trng_free(trng_t *obj)
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{
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cyhal_trng_free(&(obj->trng));
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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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uint32_t offset = 0;
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// If output is not word-aligned, write partial word
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uint32_t prealign = (uint32_t)((uintptr_t)output % sizeof(uint32_t));
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if (prealign != 0) {
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uint32_t value = cyhal_trng_generate(&(obj->trng));
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uint32_t count = sizeof(uint32_t) - prealign;
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memmove(&output[0], &value, count);
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offset += count;
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}
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// Write aligned full words
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for (; offset < length - (sizeof(uint32_t) - 1u); offset += sizeof(uint32_t)) {
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*(uint32_t *)(&output[offset]) = cyhal_trng_generate(&(obj->trng));
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}
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// Write partial trailing word if requested
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if (offset < length) {
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uint32_t value = cyhal_trng_generate(&(obj->trng));
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uint32_t count = length - offset;
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memmove(&output[offset], &value, count);
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offset += count;
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}
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*output_length = offset;
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return 0;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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