// SPDX-License-Identifier: GPL-2.0+
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/*
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* The 'rng' command prints bytes from the hardware random number generator.
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*
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* Copyright (c) 2019, Heinrich Schuchardt <xypron.glpk@gmx.de>
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*/
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#include <common.h>
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#include <command.h>
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#include <dm.h>
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#include <hexdump.h>
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#include <rng.h>
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static int do_rng(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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size_t n = 0x40;
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struct udevice *dev;
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void *buf;
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int ret = CMD_RET_SUCCESS;
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if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
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printf("No RNG device\n");
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return CMD_RET_FAILURE;
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}
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if (argc >= 2)
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n = simple_strtoul(argv[1], NULL, 16);
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buf = malloc(n);
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if (!buf) {
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printf("Out of memory\n");
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return CMD_RET_FAILURE;
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}
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if (dm_rng_read(dev, buf, n)) {
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printf("Reading RNG failed\n");
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ret = CMD_RET_FAILURE;
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} else {
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print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, n);
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}
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free(buf);
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return ret;
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}
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#ifdef CONFIG_SYS_LONGHELP
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static char rng_help_text[] =
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"[n]\n"
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" - print n random bytes\n";
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#endif
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U_BOOT_CMD(
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rng, 2, 0, do_rng,
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"print bytes from the hardware random number generator",
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rng_help_text
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);
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