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4f24ac08 HS |
1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * The 'rng' command prints bytes from the hardware random number generator. | |
4 | * | |
5 | * Copyright (c) 2019, Heinrich Schuchardt <xypron.glpk@gmx.de> | |
6 | */ | |
7 | #include <common.h> | |
8 | #include <command.h> | |
9 | #include <dm.h> | |
10 | #include <hexdump.h> | |
336d4615 | 11 | #include <malloc.h> |
4f24ac08 HS |
12 | #include <rng.h> |
13 | ||
09140113 | 14 | static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) |
4f24ac08 | 15 | { |
87ab234c | 16 | size_t n; |
c79e274c | 17 | u8 buf[64]; |
87ab234c | 18 | int devnum; |
c79e274c | 19 | struct udevice *dev; |
4f24ac08 HS |
20 | int ret = CMD_RET_SUCCESS; |
21 | ||
9a6e975c WO |
22 | if (argc == 2 && !strcmp(argv[1], "list")) { |
23 | int idx = 0; | |
24 | ||
25 | uclass_foreach_dev_probe(UCLASS_RNG, dev) { | |
26 | idx++; | |
27 | printf("RNG #%d - %s\n", dev->seq_, dev->name); | |
28 | } | |
29 | ||
30 | if (!idx) { | |
31 | log_err("No RNG device\n"); | |
32 | return CMD_RET_FAILURE; | |
33 | } | |
34 | ||
35 | return CMD_RET_SUCCESS; | |
36 | } | |
37 | ||
87ab234c SG |
38 | switch (argc) { |
39 | case 1: | |
40 | devnum = 0; | |
41 | n = 0x40; | |
42 | break; | |
43 | case 2: | |
44 | devnum = hextoul(argv[1], NULL); | |
45 | n = 0x40; | |
46 | break; | |
47 | case 3: | |
48 | devnum = hextoul(argv[1], NULL); | |
49 | n = hextoul(argv[2], NULL); | |
50 | break; | |
51 | default: | |
52 | return CMD_RET_USAGE; | |
53 | } | |
54 | ||
55 | if (uclass_get_device_by_seq(UCLASS_RNG, devnum, &dev) || !dev) { | |
4f24ac08 HS |
56 | printf("No RNG device\n"); |
57 | return CMD_RET_FAILURE; | |
58 | } | |
59 | ||
c79e274c SG |
60 | if (!n) |
61 | return 0; | |
62 | ||
63 | n = min(n, sizeof(buf)); | |
4f24ac08 HS |
64 | |
65 | if (dm_rng_read(dev, buf, n)) { | |
66 | printf("Reading RNG failed\n"); | |
67 | ret = CMD_RET_FAILURE; | |
68 | } else { | |
69 | print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, n); | |
70 | } | |
71 | ||
4f24ac08 HS |
72 | return ret; |
73 | } | |
74 | ||
4f24ac08 | 75 | U_BOOT_CMD( |
87ab234c | 76 | rng, 3, 0, do_rng, |
4f24ac08 | 77 | "print bytes from the hardware random number generator", |
9a6e975c WO |
78 | "list - list all the probed rng devices\n" |
79 | "rng [dev] [n] - print n random bytes(max 64) read from dev\n" | |
4f24ac08 | 80 | ); |