1 /*
2 * Copyright (c) 2021 Telink Semiconductor
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #define DT_DRV_COMPAT telink_b91_trng
8
9 #include <trng.h>
10 #include <zephyr/drivers/entropy.h>
11 #include <string.h>
12
13
14 /* API implementation: driver initialization */
entropy_b91_trng_init(const struct device * dev)15 static int entropy_b91_trng_init(const struct device *dev)
16 {
17 ARG_UNUSED(dev);
18
19 trng_init();
20
21 return 0;
22 }
23
24 /* API implementation: get_entropy */
entropy_b91_trng_get_entropy(const struct device * dev,uint8_t * buffer,uint16_t length)25 static int entropy_b91_trng_get_entropy(const struct device *dev,
26 uint8_t *buffer, uint16_t length)
27 {
28 ARG_UNUSED(dev);
29
30 uint32_t value = 0;
31
32 while (length) {
33 value = trng_rand();
34
35 if (length >= sizeof(value)) {
36 memcpy(buffer, &value, sizeof(value));
37 buffer += sizeof(value);
38 length -= sizeof(value);
39 } else {
40 memcpy(buffer, &value, length);
41 break;
42 }
43 }
44
45 return 0;
46 }
47
48 /* API implementation: get_entropy_isr */
entropy_b91_trng_get_entropy_isr(const struct device * dev,uint8_t * buffer,uint16_t length,uint32_t flags)49 static int entropy_b91_trng_get_entropy_isr(const struct device *dev,
50 uint8_t *buffer, uint16_t length,
51 uint32_t flags)
52 {
53 ARG_UNUSED(flags);
54
55 /* No specific handling in case of running from ISR, just call standard API */
56 entropy_b91_trng_get_entropy(dev, buffer, length);
57
58 return length;
59 }
60
61 /* Entropy driver APIs structure */
62 static const struct entropy_driver_api entropy_b91_trng_api = {
63 .get_entropy = entropy_b91_trng_get_entropy,
64 .get_entropy_isr = entropy_b91_trng_get_entropy_isr
65 };
66
67 /* Entropy driver registration */
68 DEVICE_DT_INST_DEFINE(0, entropy_b91_trng_init,
69 NULL, NULL, NULL,
70 PRE_KERNEL_1, CONFIG_ENTROPY_INIT_PRIORITY,
71 &entropy_b91_trng_api);
72
