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// SPDX-License-Identifier: GPL-2.0+
/*
* The 'rng' command prints bytes from the hardware random number generator.
*
* Copyright (c) 2019, Heinrich Schuchardt <xypron.glpk@gmx.de>
*/
#include <command.h>
#include <dm.h>
#include <hexdump.h>
#include <malloc.h>
#include <rng.h>
static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
{
size_t n;
u8 buf[64];
int devnum;
struct udevice *dev;
int ret = CMD_RET_SUCCESS, err;
if (argc == 2 && !strcmp(argv[1], "list")) {
int idx = 0;
uclass_foreach_dev_probe(UCLASS_RNG, dev) {
idx++;
printf("RNG #%d - %s\n", dev->seq_, dev->name);
}
if (!idx) {
log_err("No RNG device\n");
return CMD_RET_FAILURE;
}
return CMD_RET_SUCCESS;
}
switch (argc) {
case 1:
devnum = 0;
n = 0x40;
break;
case 2:
devnum = hextoul(argv[1], NULL);
n = 0x40;
break;
case 3:
devnum = hextoul(argv[1], NULL);
n = hextoul(argv[2], NULL);
break;
default:
return CMD_RET_USAGE;
}
if (uclass_get_device_by_seq(UCLASS_RNG, devnum, &dev) || !dev) {
printf("No RNG device\n");
return CMD_RET_FAILURE;
}
if (!n)
return 0;
n = min(n, sizeof(buf));
err = dm_rng_read(dev, buf, n);
if (err) {
puts(err == -EINTR ? "Abort\n" : "Reading RNG failed\n");
ret = CMD_RET_FAILURE;
} else {
print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, n);
}
return ret;
}
U_BOOT_CMD(
rng, 3, 0, do_rng,
"print bytes from the hardware random number generator",
"list - list all the probed rng devices\n"
"rng [dev] [n] - print n random bytes(max 64) read from dev\n"
);
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