mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

Dependents:   Nucleo_Hello_Encoder BLE_iBeaconScan AM1805_DEMO DISCO-F429ZI_ExportTemplate1 ... more

targets/TARGET_STM/trng_api.c@189:f392fc9709a3, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 22:31:08 2019 +0000
Revision:
189:f392fc9709a3
Parent:
187:0387e8f68319 
mbed library release version 165

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 149:156823d33999 1 /*
<> 149:156823d33999 2 * Hardware entropy collector for the STM32 families
<> 149:156823d33999 3 *
<> 149:156823d33999 4 * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
<> 149:156823d33999 5 * SPDX-License-Identifier: Apache-2.0
<> 149:156823d33999 6 *
<> 149:156823d33999 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
<> 149:156823d33999 8 * not use this file except in compliance with the License.
<> 149:156823d33999 9 * You may obtain a copy of the License at
<> 149:156823d33999 10 *
<> 149:156823d33999 11 * http://www.apache.org/licenses/LICENSE-2.0
<> 149:156823d33999 12 *
<> 149:156823d33999 13 * Unless required by applicable law or agreed to in writing, software
<> 149:156823d33999 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
<> 149:156823d33999 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 149:156823d33999 16 * See the License for the specific language governing permissions and
<> 149:156823d33999 17 * limitations under the License.
<> 149:156823d33999 18 *
<> 149:156823d33999 19 */
<> 149:156823d33999 20
AnnaBridge 189:f392fc9709a3 21 #if DEVICE_TRNG
<> 149:156823d33999 22
<> 149:156823d33999 23 #include <stdlib.h>
<> 149:156823d33999 24 #include "cmsis.h"
<> 149:156823d33999 25 #include "trng_api.h"
AnnaBridge 177:d650f5d4c87a 26 #include "mbed_error.h"
AnnaBridge 177:d650f5d4c87a 27 #include "mbed_critical.h"
<> 149:156823d33999 28
AnnaBridge 177:d650f5d4c87a 29 static uint8_t users = 0;
<> 149:156823d33999 30
<> 149:156823d33999 31 void trng_init(trng_t *obj)
<> 149:156823d33999 32 {
AnnaBridge 177:d650f5d4c87a 33 uint32_t dummy;
AnnaBridge 177:d650f5d4c87a 34
AnnaBridge 177:d650f5d4c87a 35 /* We're only supporting a single user of RNG */
AnnaBridge 187:0387e8f68319 36 if (core_util_atomic_incr_u8(&users, 1) > 1) {
AnnaBridge 177:d650f5d4c87a 37 error("Only 1 RNG instance supported\r\n");
AnnaBridge 177:d650f5d4c87a 38 }
AnnaBridge 177:d650f5d4c87a 39
AnnaBridge 189:f392fc9709a3 40 #if defined(RCC_PERIPHCLK_RNG)
<> 149:156823d33999 41 RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
<> 149:156823d33999 42
<> 149:156823d33999 43 /*Select PLLQ output as RNG clock source */
<> 149:156823d33999 44 PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RNG;
AnnaBridge 189:f392fc9709a3 45 #if ((CLOCK_SOURCE) & USE_PLL_MSI)
AnnaBridge 189:f392fc9709a3 46 PeriphClkInitStruct.RngClockSelection = RCC_RNGCLKSOURCE_MSI;
AnnaBridge 189:f392fc9709a3 47 #else
<> 149:156823d33999 48 PeriphClkInitStruct.RngClockSelection = RCC_RNGCLKSOURCE_PLL;
AnnaBridge 189:f392fc9709a3 49 #endif
AnnaBridge 189:f392fc9709a3 50 if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK) {
AnnaBridge 189:f392fc9709a3 51 error("RNG clock configuration error\n");
AnnaBridge 189:f392fc9709a3 52 }
<> 149:156823d33999 53 #endif
<> 149:156823d33999 54
<> 149:156823d33999 55 /* RNG Peripheral clock enable */
<> 149:156823d33999 56 __HAL_RCC_RNG_CLK_ENABLE();
<> 149:156823d33999 57
<> 149:156823d33999 58 /* Initialize RNG instance */
<> 149:156823d33999 59 obj->handle.Instance = RNG;
AnnaBridge 177:d650f5d4c87a 60 obj->handle.State = HAL_RNG_STATE_RESET;
AnnaBridge 177:d650f5d4c87a 61 obj->handle.Lock = HAL_UNLOCKED;
AnnaBridge 177:d650f5d4c87a 62
<> 149:156823d33999 63 HAL_RNG_Init(&obj->handle);
<> 149:156823d33999 64
<> 149:156823d33999 65 /* first random number generated after setting the RNGEN bit should not be used */
AnnaBridge 177:d650f5d4c87a 66 HAL_RNG_GenerateRandomNumber(&obj->handle, &dummy);
<> 149:156823d33999 67 }
<> 149:156823d33999 68
<> 149:156823d33999 69 void trng_free(trng_t *obj)
<> 149:156823d33999 70 {
<> 149:156823d33999 71 /*Disable the RNG peripheral */
<> 149:156823d33999 72 HAL_RNG_DeInit(&obj->handle);
<> 149:156823d33999 73 /* RNG Peripheral clock disable - assume we're the only users of RNG */
<> 149:156823d33999 74 __HAL_RCC_RNG_CLK_DISABLE();
AnnaBridge 177:d650f5d4c87a 75
AnnaBridge 177:d650f5d4c87a 76 users = 0;
<> 149:156823d33999 77 }
<> 149:156823d33999 78
<> 149:156823d33999 79 int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
<> 149:156823d33999 80 {
AnnaBridge 177:d650f5d4c87a 81 int ret = 0;
AnnaBridge 177:d650f5d4c87a 82 volatile uint8_t random[4];
AnnaBridge 177:d650f5d4c87a 83 *output_length = 0;
<> 149:156823d33999 84
<> 149:156823d33999 85 /* Get Random byte */
AnnaBridge 187:0387e8f68319 86 while ((*output_length < length) && (ret == 0)) {
AnnaBridge 187:0387e8f68319 87 if (HAL_RNG_GenerateRandomNumber(&obj->handle, (uint32_t *)random) != HAL_OK) {
AnnaBridge 187:0387e8f68319 88 ret = -1;
AnnaBridge 177:d650f5d4c87a 89 } else {
AnnaBridge 187:0387e8f68319 90 for (uint8_t i = 0; (i < 4) && (*output_length < length) ; i++) {
AnnaBridge 177:d650f5d4c87a 91 *output++ = random[i];
AnnaBridge 177:d650f5d4c87a 92 *output_length += 1;
AnnaBridge 177:d650f5d4c87a 93 random[i] = 0;
AnnaBridge 177:d650f5d4c87a 94 }
AnnaBridge 177:d650f5d4c87a 95 }
<> 149:156823d33999 96 }
<> 149:156823d33999 97
<> 149:156823d33999 98 /* Just be extra sure that we didn't do it wrong */
AnnaBridge 187:0387e8f68319 99 if ((__HAL_RNG_GET_FLAG(&obj->handle, (RNG_FLAG_CECS | RNG_FLAG_SECS))) != 0) {
<> 149:156823d33999 100 ret = -1;
<> 149:156823d33999 101 }
<> 149:156823d33999 102
AnnaBridge 187:0387e8f68319 103 return (ret);
<> 149:156823d33999 104 }
<> 149:156823d33999 105
<> 149:156823d33999 106 #endif