run 命令可以用于运行环境变量的中定义的命令,run bootcmd 可以运行bootcmd中启动命令
作用:可以运行我们自定义的环境变量
include/command.h
common/cli.c

/**
 * board_run_command() - Fallback function to execute a command
 *
 * When no command line features are enabled in U-Boot, this function is
 * called to execute a command. Typically the function can look at the
 * command and perform a few very specific tasks, such as booting the
 * system in a particular way.
 *
 * This function is only used when CONFIG_CMDLINE is not enabled.
 *
 * In normal situations this function should not return, since U-Boot will
 * simply hang.
 *
 * @cmdline:	Command line string to execute
 * @return 0 if OK, 1 for error
 */
int board_run_command(const char *cmdline);

int run_command(const char *cmd, int flag);
int run_command_repeatable(const char *cmd, int flag);

/**
 * Run a list of commands separated by ; or even \0
 *
 * Note that if 'len' is not -1, then the command does not need to be nul
 * terminated, Memory will be allocated for the command in that case.
 *
 * @param cmd	List of commands to run, each separated bu semicolon
 * @param len	Length of commands excluding terminator if known (-1 if not)
 * @param flag	Execution flags (CMD_FLAG_...)
 * @return 0 on success, or != 0 on error.
 */
int run_command_list(const char *cmd, int len, int flag);

/*
 * Run a command using the selected parser.
 *
 * @param cmd	Command to run
 * @param flag	Execution flags (CMD_FLAG_...)
 * @return 0 on success, or != 0 on error.
 */
int run_command(const char *cmd, int flag)
{
#if !CONFIG_IS_ENABLED(HUSH_PARSER)
	/*
	 * cli_run_command can return 0 or 1 for success, so clean up
	 * its result.
	 */
	if (cli_simple_run_command(cmd, flag) == -1)
		return 1;

	return 0;
#else
	int hush_flags = FLAG_PARSE_SEMICOLON | FLAG_EXIT_FROM_LOOP;

	if (flag & CMD_FLAG_ENV)
		hush_flags |= FLAG_CONT_ON_NEWLINE;
	return parse_string_outer(cmd, hush_flags);
#endif
}

例子(1)

env set  mybootflash " sf probe 0;sf read 0x50000000 0x0100000 0x900000; bootm 0x50000000 "
saveenv

env set  mybootnet  " mw.b 0x50000000 0xff 0x900000; tftp 0x50000000 uImage; bootm 0x50000000"
saveenv

run mybootnet
run mybootflash 

例子(2)在代码中使用

char *p;
p = env_get("mybootnet");
run_command(p,0);



/* We come here after U-Boot is initialised and ready to process commands */
void main_loop(void)
{
	const char *s;
	char *p;
	p = env_get("mybootnet");
	if(p)
	{
		printf(" main_loop  run_command(p,0)  \r\n");
		run_command(p,0);
	}

	bootstage_mark_name(BOOTSTAGE_ID_MAIN_LOOP, "main_loop");

	if (IS_ENABLED(CONFIG_VERSION_VARIABLE))
		env_set("ver", version_string);  /* set version variable */

	cli_init();


	if (IS_ENABLED(CONFIG_USE_PREBOOT))
		run_preboot_environment_command();

	if (IS_ENABLED(CONFIG_UPDATE_TFTP))
		update_tftp(0UL, NULL, NULL);

	s = bootdelay_process();
	if (cli_process_fdt(&s))
		cli_secure_boot_cmd(s);

	autoboot_command(s);

	cli_loop();
	panic("No CLI available");
}