// 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(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
  {
  	size_t n = 0x40;
  	struct udevice *dev;
  	void *buf;
  	int ret = CMD_RET_SUCCESS;
  
  	if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
  		printf("No RNG device
  ");
  		return CMD_RET_FAILURE;
  	}
  
  	if (argc >= 2)
  		n = simple_strtoul(argv[1], NULL, 16);
  
  	buf = malloc(n);
  	if (!buf) {
  		printf("Out of memory
  ");
  		return CMD_RET_FAILURE;
  	}
  
  	if (dm_rng_read(dev, buf, n)) {
  		printf("Reading RNG failed
  ");
  		ret = CMD_RET_FAILURE;
  	} else {
  		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, n);
  	}
  
  	free(buf);
  
  	return ret;
  }
  
  #ifdef CONFIG_SYS_LONGHELP
  static char rng_help_text[] =
  	"[n]
  "
  	"  - print n random bytes
  ";
  #endif
  
  U_BOOT_CMD(
  	rng, 2, 0, do_rng,
  	"print bytes from the hardware random number generator",
  	rng_help_text
  );