平台:MPC8315(POWERPC)
1.在/common/ 目录下创建自己的文件,最好前缀为cmd_.
cmd_hello.c
*********************************************************
#include<command.h>
#include<common.h>
#ifdef CONFIG_CMD_HELLO
int do_hello(cmd_tbl_t *cmdtp,int flag,int argc,char *argv)
{
printf("my test \n");
return 0;
}
U_BOOT_CMD(
hello,1,0,do_hello,"usage:test\n","help:test\n"
);
#endif
*********************************************************
2.在当前目录下修改Makefile
在目标变量最后面添加:
#ifdef CONFIG_CMD_HELLO
COBJS-y += cmd_hello.o
#endif
3.在头文件mpc83xx.h中添加对CONFIG_CMD_HELLO的定义
#define CONFIG_CMD_HELLO
编译下载后,在uboot中运行hello:
4.U_BOOT_CMD
它的定义在include/command.h中,
/**********************************************************/
#define Struct_Section __attribute__((unused, section(".u_boot_cmd"), aligned(4)))
#define U_BOOT_CMD_MKENT_COMPLETE(name,maxargs,rep,cmd,usage,help,comp) \
{#name, maxargs, rep, cmd, usage, _CMD_HELP(help) _CMD_COMPLETE(comp)}
#define U_BOOT_CMD_COMPLETE(name,maxargs,rep,cmd,usage,help,comp) \
cmd_tbl_t __u_boot_cmd_##name Struct_Section = \
U_BOOT_CMD_MKENT_COMPLETE(name,maxargs,rep,cmd,usage,help,comp)
#define U_BOOT_CMD(name,maxargs,rep,cmd,usage,help) \
U_BOOT_CMD_COMPLETE(name,maxargs,rep,cmd,usage,help,NULL)
/*******************************************************/
展开就是:#define U_BOOT_CMD(hello,1,0,do_hello,"usage:test\n","help:test\n")
cmd_tbl_t __u_boot_cmd_hello __attribute__((unused, section(".u_boot_cmd"), aligned(4)))
= {hello, 1, 0, do_hello, "usage:test\n","help:test\n" }
这儿定义了属性,就是所有的命令都存储在.u_boot_cmd节中,可以在连接脚本找到这个节。