1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0+
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * The 'rng' command prints bytes from the hardware random number generator.
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (c) 2019, Heinrich Schuchardt <xypron.glpk@gmx.de>
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun #include <common.h>
8*4882a593Smuzhiyun #include <command.h>
9*4882a593Smuzhiyun #include <dm.h>
10*4882a593Smuzhiyun #include <hexdump.h>
11*4882a593Smuzhiyun #include <rng.h>
12*4882a593Smuzhiyun
do_rng(cmd_tbl_t * cmdtp,int flag,int argc,char * const argv[])13*4882a593Smuzhiyun static int do_rng(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
14*4882a593Smuzhiyun {
15*4882a593Smuzhiyun size_t n = 0x40;
16*4882a593Smuzhiyun struct udevice *dev;
17*4882a593Smuzhiyun void *buf;
18*4882a593Smuzhiyun int ret = CMD_RET_SUCCESS;
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
21*4882a593Smuzhiyun printf("No RNG device\n");
22*4882a593Smuzhiyun return CMD_RET_FAILURE;
23*4882a593Smuzhiyun }
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun if (argc >= 2)
26*4882a593Smuzhiyun n = simple_strtoul(argv[1], NULL, 16);
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun buf = malloc(n);
29*4882a593Smuzhiyun if (!buf) {
30*4882a593Smuzhiyun printf("Out of memory\n");
31*4882a593Smuzhiyun return CMD_RET_FAILURE;
32*4882a593Smuzhiyun }
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun if (dm_rng_read(dev, buf, n)) {
35*4882a593Smuzhiyun printf("Reading RNG failed\n");
36*4882a593Smuzhiyun ret = CMD_RET_FAILURE;
37*4882a593Smuzhiyun } else {
38*4882a593Smuzhiyun print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, n);
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun free(buf);
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun return ret;
44*4882a593Smuzhiyun }
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun #ifdef CONFIG_SYS_LONGHELP
47*4882a593Smuzhiyun static char rng_help_text[] =
48*4882a593Smuzhiyun "[n]\n"
49*4882a593Smuzhiyun " - print n random bytes\n";
50*4882a593Smuzhiyun #endif
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun U_BOOT_CMD(
53*4882a593Smuzhiyun rng, 2, 0, do_rng,
54*4882a593Smuzhiyun "print bytes from the hardware random number generator",
55*4882a593Smuzhiyun rng_help_text
56*4882a593Smuzhiyun );
57