04-S3C2440u-boot学习之u-boot分析(4)之u-boot命令实现

参考《韦东山1期视频》第09课第4节 u-boot分析之u-boot命令实现.WMV

1解析命令：如存在;

while (*str) {

/*

* Find separator, or string end

* Allow simple escape of ';' by writing ";"

*/

for (inquotes = 0, sep = str; *sep; sep++) {

if ((*sep==''') &&

    (*(sep-1) != '\'))

inquotes=!inquotes;

if (!inquotes &&

    (*sep == ';') && /* separator */

    ( sep != str) && /* past string start */

    (*(sep-1) != '\')) /* and NOT escaped */

break;

}

2提取命令参数

/* Extract arguments */

if ((argc = parse_line (finaltoken, argv)) == 0) {

rc = -1; /* no command at all */

continue;

}

/* Look up command in command table */

if ((cmdtp = find_cmd(argv[0])) == NULL) {

printf ("Unknown command '%s' - try 'help'n", argv[0]);

rc = -1; /* give up after bad command */

continue;

}

struct cmd_tbl_s {

char *name; /* Command Name */

int maxargs; /* maximum number of arguments */

int repeatable; /* autorepeat allowed? */

/* Implementation function */

int (*cmd)(struct cmd_tbl_s *, int, int, char *[]);

char *usage; /* Usage message (short) */

#ifdef CFG_LONGHELP

char *help; /* Help  message (long) */

#endif

#ifdef CONFIG_AUTO_COMPLETE

/* do auto completion on the arguments */

int (*complete)(int argc, char *argv[], char last_char, int maxv, char *cmdv[]);

#endif

};

3增加一个hello命令

参考bootm，在common下创建hello_cmd.c

实现do_hello方法和U_BOOT_CMD

拷贝c文件到common目录下

修改common下的makefile文件：

增加cmd_hello.o

重新make。

执行hello。