uboot中CMD的实现

CMD配置位于config_cmd_default.h   configs/at91/sam9g10ek.h

头文件位于include/command.h

41 struct cmd_tbl_s {
 42     char        *name;      /* Command Name         */
 43     int     maxargs;    /* maximum number of arguments  */
 44     int     repeatable; /* autorepeat allowed?      */
 45                     /* Implementation function  */
 46     int     (*cmd)(struct cmd_tbl_s *, int, int, char *[]);
 47     char        *usage;     /* Usage message    (short) */
 48 #ifdef  CFG_LONGHELP
 49     char        *help;      /* Help  message    (long)  */
 50 #endif
 51 #ifdef CONFIG_AUTO_COMPLETE
 52     /* do auto completion on the arguments */
 53     int     (*complete)(int argc, char *argv[], char last_char, int maxv, ch    ar *cmdv[]);
 54 #endif
 55 };
 56
 57 typedef struct cmd_tbl_s    cmd_tbl_t;

71 /*
 72  * Monitor Command
 73  *
 74  * All commands use a common argument format:
 75  *
 76  * void function (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
 77  */
 78
 79 typedef void    command_t (cmd_tbl_t *, int, int, char *[]);

89 #define Struct_Section  __attribute__ ((unused,section (".u_boot_cmd")))

91 #ifdef  CFG_LONGHELP
 92
 93 #define U_BOOT_CMD(name,maxargs,rep,cmd,usage,help) \
 94 cmd_tbl_t __u_boot_cmd_##name Struct_Section = {#name, maxargs, rep, cmd, usage, help}
 95
 96 #else   /* no long help info */
 97
 98 #define U_BOOT_CMD(name,maxargs,rep,cmd,usage,help) \
 99 cmd_tbl_t __u_boot_cmd_##name Struct_Section = {#name, maxargs, rep, cmd, usage}
100
101 #endif  /* CFG_LONGHELP */

以最简单的命令ersion为例介绍：

位于lib_arm/board.c

75 const char version_string[] =
 76     U_BOOT_VERSION" (" __DATE__ " - " __TIME__ ")"CONFIG_IDENT_STRING;

common/command.c

31 int
 32 do_version (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 33 {
 34     extern char version_string[];
 35     printf ("\n%s\n", version_string);
 36     return 0;
 37 }
 38
 39 U_BOOT_CMD(
 40     version,    1,      1,  do_version,
 41     "version - print monitor version\n",
 42     NULL
 43 );
 44