EL4121 Embedded System / mbed-os

mbed-os

Dependents:   cobaLCDJoyMotor_Thread odometry_omni_3roda_v3 odometry_omni_3roda_v1 odometry_omni_3roda_v2 ... more

targets/TARGET_STM/trng_api.c@0:b74591d5ab33, 2017-12-11 (annotated)

Committer:
be_bryan
Date:
Mon Dec 11 17:54:04 2017 +0000
Revision:
0:b74591d5ab33
motor ++

Who changed what in which revision?

UserRevisionLine numberNew contents of line
be_bryan 0:b74591d5ab33 1 /*
be_bryan 0:b74591d5ab33 2 * Hardware entropy collector for the STM32 families
be_bryan 0:b74591d5ab33 3 *
be_bryan 0:b74591d5ab33 4 * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
be_bryan 0:b74591d5ab33 5 * SPDX-License-Identifier: Apache-2.0
be_bryan 0:b74591d5ab33 6 *
be_bryan 0:b74591d5ab33 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
be_bryan 0:b74591d5ab33 8 * not use this file except in compliance with the License.
be_bryan 0:b74591d5ab33 9 * You may obtain a copy of the License at
be_bryan 0:b74591d5ab33 10 *
be_bryan 0:b74591d5ab33 11 * http://www.apache.org/licenses/LICENSE-2.0
be_bryan 0:b74591d5ab33 12 *
be_bryan 0:b74591d5ab33 13 * Unless required by applicable law or agreed to in writing, software
be_bryan 0:b74591d5ab33 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
be_bryan 0:b74591d5ab33 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
be_bryan 0:b74591d5ab33 16 * See the License for the specific language governing permissions and
be_bryan 0:b74591d5ab33 17 * limitations under the License.
be_bryan 0:b74591d5ab33 18 *
be_bryan 0:b74591d5ab33 19 */
be_bryan 0:b74591d5ab33 20
be_bryan 0:b74591d5ab33 21 #if defined(DEVICE_TRNG)
be_bryan 0:b74591d5ab33 22
be_bryan 0:b74591d5ab33 23 #include <stdlib.h>
be_bryan 0:b74591d5ab33 24 #include "cmsis.h"
be_bryan 0:b74591d5ab33 25 #include "trng_api.h"
be_bryan 0:b74591d5ab33 26 #include "mbed_error.h"
be_bryan 0:b74591d5ab33 27 #include "mbed_critical.h"
be_bryan 0:b74591d5ab33 28
be_bryan 0:b74591d5ab33 29 static uint8_t users = 0;
be_bryan 0:b74591d5ab33 30
be_bryan 0:b74591d5ab33 31 void trng_init(trng_t *obj)
be_bryan 0:b74591d5ab33 32 {
be_bryan 0:b74591d5ab33 33 uint32_t dummy;
be_bryan 0:b74591d5ab33 34
be_bryan 0:b74591d5ab33 35 /* We're only supporting a single user of RNG */
be_bryan 0:b74591d5ab33 36 if (core_util_atomic_incr_u8(&users, 1) > 1 ) {
be_bryan 0:b74591d5ab33 37 error("Only 1 RNG instance supported\r\n");
be_bryan 0:b74591d5ab33 38 }
be_bryan 0:b74591d5ab33 39
be_bryan 0:b74591d5ab33 40 #if defined(TARGET_STM32L4)
be_bryan 0:b74591d5ab33 41 RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
be_bryan 0:b74591d5ab33 42
be_bryan 0:b74591d5ab33 43 /*Select PLLQ output as RNG clock source */
be_bryan 0:b74591d5ab33 44 PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RNG;
be_bryan 0:b74591d5ab33 45 PeriphClkInitStruct.RngClockSelection = RCC_RNGCLKSOURCE_PLL;
be_bryan 0:b74591d5ab33 46 HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
be_bryan 0:b74591d5ab33 47 #endif
be_bryan 0:b74591d5ab33 48
be_bryan 0:b74591d5ab33 49 /* RNG Peripheral clock enable */
be_bryan 0:b74591d5ab33 50 __HAL_RCC_RNG_CLK_ENABLE();
be_bryan 0:b74591d5ab33 51
be_bryan 0:b74591d5ab33 52 /* Initialize RNG instance */
be_bryan 0:b74591d5ab33 53 obj->handle.Instance = RNG;
be_bryan 0:b74591d5ab33 54 obj->handle.State = HAL_RNG_STATE_RESET;
be_bryan 0:b74591d5ab33 55 obj->handle.Lock = HAL_UNLOCKED;
be_bryan 0:b74591d5ab33 56
be_bryan 0:b74591d5ab33 57 HAL_RNG_Init(&obj->handle);
be_bryan 0:b74591d5ab33 58
be_bryan 0:b74591d5ab33 59 /* first random number generated after setting the RNGEN bit should not be used */
be_bryan 0:b74591d5ab33 60 HAL_RNG_GenerateRandomNumber(&obj->handle, &dummy);
be_bryan 0:b74591d5ab33 61 }
be_bryan 0:b74591d5ab33 62
be_bryan 0:b74591d5ab33 63 void trng_free(trng_t *obj)
be_bryan 0:b74591d5ab33 64 {
be_bryan 0:b74591d5ab33 65 /*Disable the RNG peripheral */
be_bryan 0:b74591d5ab33 66 HAL_RNG_DeInit(&obj->handle);
be_bryan 0:b74591d5ab33 67 /* RNG Peripheral clock disable - assume we're the only users of RNG */
be_bryan 0:b74591d5ab33 68 __HAL_RCC_RNG_CLK_DISABLE();
be_bryan 0:b74591d5ab33 69
be_bryan 0:b74591d5ab33 70 users = 0;
be_bryan 0:b74591d5ab33 71 }
be_bryan 0:b74591d5ab33 72
be_bryan 0:b74591d5ab33 73 int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
be_bryan 0:b74591d5ab33 74 {
be_bryan 0:b74591d5ab33 75 int ret = 0;
be_bryan 0:b74591d5ab33 76 volatile uint8_t random[4];
be_bryan 0:b74591d5ab33 77 *output_length = 0;
be_bryan 0:b74591d5ab33 78
be_bryan 0:b74591d5ab33 79 /* Get Random byte */
be_bryan 0:b74591d5ab33 80 while ((*output_length < length) && (ret ==0)) {
be_bryan 0:b74591d5ab33 81 if ( HAL_RNG_GenerateRandomNumber(&obj->handle, (uint32_t *)random ) != HAL_OK) {
be_bryan 0:b74591d5ab33 82 ret = -1;
be_bryan 0:b74591d5ab33 83 } else {
be_bryan 0:b74591d5ab33 84 for (uint8_t i =0; (i < 4) && (*output_length < length) ; i++) {
be_bryan 0:b74591d5ab33 85 *output++ = random[i];
be_bryan 0:b74591d5ab33 86 *output_length += 1;
be_bryan 0:b74591d5ab33 87 random[i] = 0;
be_bryan 0:b74591d5ab33 88 }
be_bryan 0:b74591d5ab33 89 }
be_bryan 0:b74591d5ab33 90 }
be_bryan 0:b74591d5ab33 91
be_bryan 0:b74591d5ab33 92 /* Just be extra sure that we didn't do it wrong */
be_bryan 0:b74591d5ab33 93 if( ( __HAL_RNG_GET_FLAG(&obj->handle, (RNG_FLAG_CECS | RNG_FLAG_SECS)) ) != 0 ) {
be_bryan 0:b74591d5ab33 94 ret = -1;
be_bryan 0:b74591d5ab33 95 }
be_bryan 0:b74591d5ab33 96
be_bryan 0:b74591d5ab33 97 return( ret );
be_bryan 0:b74591d5ab33 98 }
be_bryan 0:b74591d5ab33 99
be_bryan 0:b74591d5ab33 100 #endif