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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 <common.h>
- #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;
- 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));
- if (dm_rng_read(dev, buf, n)) {
- printf("Reading RNG failed\n");
- ret = CMD_RET_FAILURE;
- } else {
- print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, n);
- }
- return ret;
- }
- #ifdef CONFIG_SYS_LONGHELP
- static char rng_help_text[] =
- "[dev [n]]\n"
- " - print n random bytes(max 64) read from dev\n";
- #endif
- U_BOOT_CMD(
- rng, 3, 0, do_rng,
- "print bytes from the hardware random number generator",
- rng_help_text
- );
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