blob: d678992d46fe51cebcb19041d031aaa6216e5eb1 [file] [log] [blame]
wdenk0d498392003-07-01 21:06:45 +00001
2Commands are added to U-Boot by creating a new command structure.
3This is done by first including command.h
4
5Then using the U_BOOT_CMD() macro to fill in a cmd_tbl_t struct.
6
7U_BOOT_CMD(name,maxargs,repeatable,command,"usage","help")
8
9name: is the name of the commad. THIS IS NOT a string.
10maxargs: the maximumn numbers of arguments this function takes
11command: Function pointer (*cmd)(struct cmd_tbl_s *, int, int, char *[]);
12usage: Short description. This is a string
13help: long description. This is a string
14
15
16**** Behinde the scene ******
17
18The structure created is named with a special prefix (__u_boot_cmd_)
19and placed by the linker in a special section.
20
21This makes it possible for the final link to extract all commands
22compiled into any object code and construct a static array so the
23command can be found in an array starting at __u_boot_cmd_start.
24
25If a new board is defined do not forget to define the command section
26by writing in u-boot.lds ($(TOPDIR)/board/boardname/u-boot.lds) these
273 lines:
28
29 __u_boot_cmd_start = .;
30 .u_boot_cmd : { *(.u_boot_cmd) }
31 __u_boot_cmd_end = .;