mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

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

targets/TARGET_RDA/TARGET_UNO_91H/trng_api.c@189:f392fc9709a3, 2019-02-20 (annotated)

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

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AnnaBridge 189:f392fc9709a3 1 /*
AnnaBridge 189:f392fc9709a3 2 * Hardware entropy collector for the UNO_91H, using RDA's TRNG
AnnaBridge 189:f392fc9709a3 3 *
AnnaBridge 189:f392fc9709a3 4 * Copyright (C) 2006-2018, ARM Limited, All Rights Reserved
AnnaBridge 189:f392fc9709a3 5 * SPDX-License-Identifier: Apache-2.0
AnnaBridge 189:f392fc9709a3 6 *
AnnaBridge 189:f392fc9709a3 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
AnnaBridge 189:f392fc9709a3 8 * not use this file except in compliance with the License.
AnnaBridge 189:f392fc9709a3 9 * You may obtain a copy of the License at
AnnaBridge 189:f392fc9709a3 10 *
AnnaBridge 189:f392fc9709a3 11 * http://www.apache.org/licenses/LICENSE-2.0
AnnaBridge 189:f392fc9709a3 12 *
AnnaBridge 189:f392fc9709a3 13 * Unless required by applicable law or agreed to in writing, software
AnnaBridge 189:f392fc9709a3 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
AnnaBridge 189:f392fc9709a3 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
AnnaBridge 189:f392fc9709a3 16 * See the License for the specific language governing permissions and
AnnaBridge 189:f392fc9709a3 17 * limitations under the License.
AnnaBridge 189:f392fc9709a3 18 *
AnnaBridge 189:f392fc9709a3 19 */
AnnaBridge 189:f392fc9709a3 20
AnnaBridge 189:f392fc9709a3 21 #if DEVICE_TRNG
AnnaBridge 189:f392fc9709a3 22
AnnaBridge 189:f392fc9709a3 23 #include "cmsis.h"
AnnaBridge 189:f392fc9709a3 24 #include "trng_api.h"
AnnaBridge 189:f392fc9709a3 25 #include "us_ticker_api.h"
AnnaBridge 189:f392fc9709a3 26
AnnaBridge 189:f392fc9709a3 27 #define rRNG_CLKGATE (RDA_SCU->CLKGATE0)
AnnaBridge 189:f392fc9709a3 28 #define rRNG_CLKGEN (RDA_DMACFG->dma_func_ctrl)
AnnaBridge 189:f392fc9709a3 29 #define rTRNG_CTRL (RDA_RNG->TCTRL)
AnnaBridge 189:f392fc9709a3 30 #define rPRNG_DATA (RDA_RNG->PD)
AnnaBridge 189:f392fc9709a3 31
AnnaBridge 189:f392fc9709a3 32 static uint32_t trng_inited = 0;
AnnaBridge 189:f392fc9709a3 33
AnnaBridge 189:f392fc9709a3 34 /** trng_get_byte
AnnaBridge 189:f392fc9709a3 35 * @brief Get one byte of entropy from the RNG, assuming it is up and running.
AnnaBridge 189:f392fc9709a3 36 * @param obj TRNG obj
AnnaBridge 189:f392fc9709a3 37 * @param pointer to the hardware generated random byte.
AnnaBridge 189:f392fc9709a3 38 */
AnnaBridge 189:f392fc9709a3 39 static void trng_get_byte(trng_t *obj, unsigned char *byte )
AnnaBridge 189:f392fc9709a3 40 {
AnnaBridge 189:f392fc9709a3 41 if (0U == obj->byte_idx) {
AnnaBridge 189:f392fc9709a3 42 uint32_t start_time = us_ticker_read();
AnnaBridge 189:f392fc9709a3 43 /* Delay for PRNG data ready, generate 4-byte per 32us */
AnnaBridge 189:f392fc9709a3 44 while ((us_ticker_read() - start_time) <= 32);
AnnaBridge 189:f392fc9709a3 45 }
AnnaBridge 189:f392fc9709a3 46 *byte = (unsigned char)((rPRNG_DATA >> (obj->byte_idx << 3)) & 0x00FFUL);
AnnaBridge 189:f392fc9709a3 47 obj->byte_idx++;
AnnaBridge 189:f392fc9709a3 48 obj->byte_idx &= 0x03U;
AnnaBridge 189:f392fc9709a3 49 }
AnnaBridge 189:f392fc9709a3 50
AnnaBridge 189:f392fc9709a3 51 void trng_init(trng_t *obj)
AnnaBridge 189:f392fc9709a3 52 {
AnnaBridge 189:f392fc9709a3 53 uint32_t regval, start_time = 0;
AnnaBridge 189:f392fc9709a3 54 volatile uint32_t count = 10;
AnnaBridge 189:f392fc9709a3 55
AnnaBridge 189:f392fc9709a3 56 if(trng_inited == 1)
AnnaBridge 189:f392fc9709a3 57 return;
AnnaBridge 189:f392fc9709a3 58
AnnaBridge 189:f392fc9709a3 59 obj->dma_clk_flag = (uint8_t)((rRNG_CLKGATE >> 18) & 0x01U);
AnnaBridge 189:f392fc9709a3 60 obj->byte_idx = 0;
AnnaBridge 189:f392fc9709a3 61 if (0x00U == obj->dma_clk_flag) {
AnnaBridge 189:f392fc9709a3 62 /* DMA Peripheral clock enable */
AnnaBridge 189:f392fc9709a3 63 rRNG_CLKGATE |= (0x01UL << 18);
AnnaBridge 189:f392fc9709a3 64 /* dealy after clk en */
AnnaBridge 189:f392fc9709a3 65 while(count--);
AnnaBridge 189:f392fc9709a3 66 }
AnnaBridge 189:f392fc9709a3 67 /* RNG Engine clock enable */
AnnaBridge 189:f392fc9709a3 68 rRNG_CLKGEN |= (0x01UL << 30);
AnnaBridge 189:f392fc9709a3 69 /* Set TRNG enable bit, once mode */
AnnaBridge 189:f392fc9709a3 70 regval = rTRNG_CTRL | ((0x01UL << 4) | (0xFFUL << 16));
AnnaBridge 189:f392fc9709a3 71 rTRNG_CTRL = regval & ~((0x01UL << 1) | (0x01UL << 2) | (0x01UL << 3));
AnnaBridge 189:f392fc9709a3 72
AnnaBridge 189:f392fc9709a3 73 us_ticker_init();
AnnaBridge 189:f392fc9709a3 74
AnnaBridge 189:f392fc9709a3 75 /*Entropy data was mixed by TRNG seed and noise, so we add one 32us delay to
AnnaBridge 189:f392fc9709a3 76 ensure all 32 bits of seed is entropy when init and
AnnaBridge 189:f392fc9709a3 77 another delay to update noise data when get data.
AnnaBridge 189:f392fc9709a3 78 */
AnnaBridge 189:f392fc9709a3 79
AnnaBridge 189:f392fc9709a3 80 /* Delay for TRNG seed ready */
AnnaBridge 189:f392fc9709a3 81 start_time = us_ticker_read();
AnnaBridge 189:f392fc9709a3 82 while ((us_ticker_read() - start_time) <= 32);
AnnaBridge 189:f392fc9709a3 83
AnnaBridge 189:f392fc9709a3 84 rTRNG_CTRL |= (0x01UL << 0);
AnnaBridge 189:f392fc9709a3 85
AnnaBridge 189:f392fc9709a3 86 trng_inited = 1;
AnnaBridge 189:f392fc9709a3 87 }
AnnaBridge 189:f392fc9709a3 88
AnnaBridge 189:f392fc9709a3 89 void trng_free(trng_t *obj)
AnnaBridge 189:f392fc9709a3 90 {
AnnaBridge 189:f392fc9709a3 91 if(trng_inited == 0)
AnnaBridge 189:f392fc9709a3 92 return;
AnnaBridge 189:f392fc9709a3 93 /* Clear TRNG enable bit */
AnnaBridge 189:f392fc9709a3 94 rTRNG_CTRL = 0x00UL;
AnnaBridge 189:f392fc9709a3 95 /* RNG Engine clock disable */
AnnaBridge 189:f392fc9709a3 96 rRNG_CLKGEN &= ~(0x01UL << 30);
AnnaBridge 189:f392fc9709a3 97 if (0x00U == obj->dma_clk_flag) {
AnnaBridge 189:f392fc9709a3 98 /* DMA Peripheral clock disable */
AnnaBridge 189:f392fc9709a3 99 rRNG_CLKGATE &= ~(0x01UL << 18);
AnnaBridge 189:f392fc9709a3 100 }
AnnaBridge 189:f392fc9709a3 101 trng_inited = 0;
AnnaBridge 189:f392fc9709a3 102 }
AnnaBridge 189:f392fc9709a3 103
AnnaBridge 189:f392fc9709a3 104 int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
AnnaBridge 189:f392fc9709a3 105 {
AnnaBridge 189:f392fc9709a3 106 int ret = 0;
AnnaBridge 189:f392fc9709a3 107
AnnaBridge 189:f392fc9709a3 108 if(trng_inited != 1)
AnnaBridge 189:f392fc9709a3 109 return -1;
AnnaBridge 189:f392fc9709a3 110
AnnaBridge 189:f392fc9709a3 111 /* Get Random byte */
AnnaBridge 189:f392fc9709a3 112 for (uint32_t i = 0; i < length; i++) {
AnnaBridge 189:f392fc9709a3 113 trng_get_byte(obj, output + i);
AnnaBridge 189:f392fc9709a3 114 }
AnnaBridge 189:f392fc9709a3 115
AnnaBridge 189:f392fc9709a3 116 *output_length = length;
AnnaBridge 189:f392fc9709a3 117
AnnaBridge 189:f392fc9709a3 118 return ret;
AnnaBridge 189:f392fc9709a3 119 }
AnnaBridge 189:f392fc9709a3 120
AnnaBridge 189:f392fc9709a3 121 #endif