1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2019, Linaro Limited
4 */
5
6 #include <common.h>
7 #include <dm.h>
8 #include <rand.h>
9 #include <rng.h>
10
11 #include <linux/string.h>
12
sandbox_rng_read(struct udevice * dev,void * data,size_t len)13 static int sandbox_rng_read(struct udevice *dev, void *data, size_t len)
14 {
15 unsigned int i, seed, random;
16 unsigned char *buf = data;
17 size_t nrem, nloops;
18
19 if (!len)
20 return 0;
21
22 nloops = len / sizeof(random);
23 seed = get_timer(0) ^ rand();
24 srand(seed);
25
26 for (i = 0, nrem = len; i < nloops; i++) {
27 random = rand();
28 memcpy(buf, &random, sizeof(random));
29 buf += sizeof(random);
30 nrem -= sizeof(random);
31 }
32
33 if (nrem) {
34 random = rand();
35 memcpy(buf, &random, nrem);
36 }
37
38 return 0;
39 }
40
41 static const struct dm_rng_ops sandbox_rng_ops = {
42 .read = sandbox_rng_read,
43 };
44
45 static const struct udevice_id sandbox_rng_match[] = {
46 {
47 .compatible = "sandbox,sandbox-rng",
48 },
49 {},
50 };
51
52 U_BOOT_DRIVER(sandbox_rng) = {
53 .name = "sandbox-rng",
54 .id = UCLASS_RNG,
55 .of_match = sandbox_rng_match,
56 .ops = &sandbox_rng_ops,
57 };
58