arm_hal_random.c

00001 /*
00002  * Copyright (c) 2015, 2018, Arm Limited and affiliates.
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 #include "ns_types.h"
00018 #include "arm_hal_random.h"
00019 
00020 #include "mbedtls/entropy_poll.h"
00021 
00022 #ifdef MBEDTLS_ENTROPY_HARDWARE_ALT
00023 #if defined(MBEDTLS_PLATFORM_C)
00024 #include "mbedtls/platform.h"
00025 #endif
00026 #endif
00027 
00028 void arm_random_module_init(void)
00029 {
00030 }
00031 
00032 uint32_t arm_random_seed_get(void)
00033 {
00034     uint32_t result = 0;
00035 #ifdef MBEDTLS_ENTROPY_HARDWARE_ALT
00036 #if defined(MBEDTLS_PLATFORM_C)
00037     mbedtls_platform_setup(NULL);
00038 #endif /* MBEDTLS_PLATFORM_C */
00039     /* Grab a seed from a function we provide for mbedtls */
00040     size_t len;
00041     mbedtls_hardware_poll(NULL, (uint8_t *) &result, sizeof result, &len);
00042 #if defined(MBEDTLS_PLATFORM_C)
00043     mbedtls_platform_teardown(NULL);
00044 #endif /* MBEDTLS_PLATFORM_C */
00045 #endif
00046     return result;
00047 }