[429] | 1 | /* mbed Microcontroller Library
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| 2 | * Copyright (c) 2006-2017 ARM Limited
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| 3 | *
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| 4 | * Licensed under the Apache License, Version 2.0 (the "License");
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| 5 | * you may not use this file except in compliance with the License.
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| 6 | * You may obtain a copy of the License at
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| 7 | *
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| 8 | * http://www.apache.org/licenses/LICENSE-2.0
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| 9 | *
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| 10 | * Unless required by applicable law or agreed to in writing, software
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| 11 | * distributed under the License is distributed on an "AS IS" BASIS,
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| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| 13 | * See the License for the specific language governing permissions and
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| 14 | * limitations under the License.
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| 15 | */
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| 16 |
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| 17 | #if defined(DEVICE_TRNG)
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| 18 | #include "mbed.h"
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| 19 |
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| 20 | #define ESP32_I2C_ADDR (0x28<<1)
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| 21 |
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| 22 | void trng_init_esp32(void) {
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| 23 | /* P3_10(EN), P3_9(IO0) */
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| 24 | if (((GPIOP3 & 0x0400) == 0)
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| 25 | || ((GPIOPMC3 & 0x0400) != 0)
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| 26 | || ((GPIOPM3 & 0x0400) != 0)
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| 27 |
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| 28 | || ((GPIOP3 & 0x0200) == 0)
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| 29 | || ((GPIOPMC3 & 0x0200) != 0)
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| 30 | || ((GPIOPM3 & 0x0200) != 0)) {
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| 31 |
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| 32 | /* P3_10(EN) */
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| 33 | GPIOP3 &= ~0x0400; /* Outputs low level */
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| 34 | GPIOPMC3 &= ~0x0400; /* Port mode */
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| 35 | GPIOPM3 &= ~0x0400; /* Output mode */
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| 36 |
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| 37 | /* P3_9(IO0) */
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| 38 | GPIOP3 &= ~0x0200; /* Outputs low level */
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| 39 | GPIOPMC3 &= ~0x0200; /* Port mode */
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| 40 | GPIOPM3 &= ~0x0200; /* Output mode */
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| 41 |
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| 42 | GPIOP3 |= 0x2000; /* Outputs hi level */
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| 43 | wait_ms(5);
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| 44 | GPIOP3 |= 0x0400; /* Outputs hi level */
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| 45 | }
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| 46 | }
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| 47 |
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| 48 | void trng_free_esp32(void) {
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| 49 | // do nothing
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| 50 | }
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| 51 |
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| 52 | int trng_get_bytes_esp32(uint8_t *output, size_t length, size_t *output_length) {
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| 53 | I2C mI2c(I2C_SDA, I2C_SCL);
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| 54 | int ret;
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| 55 | char send_data[1];
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| 56 | char recv_data[4];
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| 57 | size_t idx = 0;
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| 58 | int i;
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| 59 | int err_cnt = 0;
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| 60 |
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| 61 | while (idx < length) {
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| 62 | send_data[0] = 0;
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| 63 | ret = mI2c.write(ESP32_I2C_ADDR, send_data, 1);
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| 64 | if (ret == 0) {
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| 65 | mI2c.read(ESP32_I2C_ADDR, recv_data, sizeof(recv_data));
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| 66 | for (i = 0; (i < 4) && (idx < length); i++) {
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| 67 | output[idx++] = recv_data[i];
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| 68 | }
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| 69 | } else {
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| 70 | err_cnt++;
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| 71 | if (err_cnt >= 20) {
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| 72 | break;
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| 73 | }
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| 74 | wait_ms(100);
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| 75 | }
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| 76 | }
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| 77 | if (output_length != NULL) {
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| 78 | *output_length = idx;
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| 79 | }
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| 80 |
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| 81 | return (idx != 0 ? 0 : -1);
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| 82 | }
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| 83 | #endif
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