[J-u-boot.git] / cmd / rng.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * The 'rng' command prints bytes from the hardware random number generator.
 *
 * Copyright (c) 2019, Heinrich Schuchardt <[email protected]>
 */
#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 probed rng devices\n"
	"rng [dev [n]] - print n random bytes (max 64) read from dev\n"
);
Commit	Line	Data
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 <[email protected]>
	6	*/
4f24ac08 HS	7	#include <command.h>
	8	#include <dm.h>
	9	#include <hexdump.h>
336d4615	10	#include <malloc.h>
4f24ac08 HS	11	#include <rng.h>
4f24ac08 HS	12
09140113	13	static int do_rng(struct cmd_tbl cmdtp, int flag, int argc, char const argv[])
4f24ac08	14	{
87ab234c	15	size_t n;
c79e274c	16	u8 buf[64];
87ab234c	17	int devnum;
c79e274c	18	struct udevice *dev;
144c0167	19	int ret = CMD_RET_SUCCESS, err;
4f24ac08	20
9a6e975c WO	21	if (argc == 2 && !strcmp(argv[1], "list")) {
	22	int idx = 0;
	23
	24	uclass_foreach_dev_probe(UCLASS_RNG, dev) {
	25	idx++;
	26	printf("RNG #%d - %s\n", dev->seq_, dev->name);
	27	}
	28
	29	if (!idx) {
	30	log_err("No RNG device\n");
	31	return CMD_RET_FAILURE;
	32	}
	33
	34	return CMD_RET_SUCCESS;
	35	}
	36
87ab234c SG	37	switch (argc) {
	38	case 1:
	39	devnum = 0;
	40	n = 0x40;
	41	break;
	42	case 2:
	43	devnum = hextoul(argv[1], NULL);
	44	n = 0x40;
	45	break;
	46	case 3:
	47	devnum = hextoul(argv[1], NULL);
	48	n = hextoul(argv[2], NULL);
	49	break;
	50	default:
	51	return CMD_RET_USAGE;
	52	}
	53
	54	if (uclass_get_device_by_seq(UCLASS_RNG, devnum, &dev) \|\| !dev) {
4f24ac08 HS	55	printf("No RNG device\n");
	56	return CMD_RET_FAILURE;
	57	}
	58
c79e274c SG	59	if (!n)
	60	return 0;
	61
	62	n = min(n, sizeof(buf));
4f24ac08	63
144c0167 MB	64	err = dm_rng_read(dev, buf, n);
	65	if (err) {
	66	puts(err == -EINTR ? "Abort\n" : "Reading RNG failed\n");
4f24ac08 HS	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",
528b6b81 HS	78	"list - list all probed rng devices\n"
528b6b81 HS	79	"rng [dev [n]] - print n random bytes (max 64) read from dev\n"
4f24ac08	80	);