blob: 27815d2ba18faada4344e68ed65ac3b188569797 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
Commands are added to U-Boot by creating a new command structure.
This is done by first including command.h, then using the U_BOOT_CMD() macro
to fill in a cmd_tbl_t struct.
U_BOOT_CMD(name,maxargs,repeatable,command,"usage","help")
name: is the name of the commad. THIS IS NOT a string.
maxargs: the maximum number of arguments this function takes
repeatable: either 0 or 1 to indicate if autorepeat is allowed
command: Function pointer (*cmd)(struct cmd_tbl_s *, int, int, char *[]);
usage: Short description. This is a string
help: Long description. This is a string
**** Behind the scene ******
The structure created is named with a special prefix (__u_boot_cmd_)
and placed by the linker in a special section.
This makes it possible for the final link to extract all commands
compiled into any object code and construct a static array so the
command can be found in an array starting at __u_boot_cmd_start.
If a new board is defined do not forget to define the command section
by writing in u-boot.lds ($(TOPDIR)/board/boardname/u-boot.lds) these
3 lines:
__u_boot_cmd_start = .;
.u_boot_cmd : { *(.u_boot_cmd) }
__u_boot_cmd_end = .;
|
