arm9_uboot添加命令

蔚落 2023-06-01 06:20 13阅读 0赞

串口接收到数据，并传递给run\_command()函数，run\_command()函数调用common/command.c中实现的find\_cmd()函数在u\_boot\_list段内查找命令，并返回cmd\_tbl\_t结构。然后run\_command()函数使用返回的cmd\_tbl\_t结构中的函数指针调用do\_hello()，从而完成命令的执行

cmd_tbl_t *find_cmd (const char *cmd)
    {
        cmd_tbl_t *cmdtp;
        cmd_tbl_t *cmdtp_temp = &__u_boot_cmd_start;    /*Init value */
        const char *p;
        int len;
        int n_found = 0;
    
        /*
         * Some commands allow length modifiers (like "cp.b");
         * compare command name only until first dot.
         */
        len = ((p = strchr(cmd, '.')) == NULL) ? strlen (cmd) : (p - cmd);
    
        for (cmdtp = &__u_boot_cmd_start;
             cmdtp != &__u_boot_cmd_end;
             cmdtp++) {
            if (strncmp (cmd, cmdtp->name, len) == 0) {
                if (len == strlen (cmdtp->name))
                    return cmdtp;    /* full match */
    
                cmdtp_temp = cmdtp;    /* abbreviated command ? */
                n_found++;
            }
        }
        if (n_found == 1) {            /* exactly one match */
            return cmdtp_temp;
        }
    
        return NULL;    /* not found or ambiguous command */
    }

在u-boot.1.1.6/board/100ask24x0/u-boot.lds中

__u_boot_cmd_start = .;
        .u_boot_cmd : { *(.u_boot_cmd) }
        __u_boot_cmd_end = .;

在u-boot.1.1.6/include/command.h中

#define U_BOOT_CMD(name,maxargs,rep,cmd,usage,help) \
    cmd_tbl_t __u_boot_cmd_##name Struct_Section = {#name, maxargs, rep, cmd, usage}

#define Struct_Section  __attribute__ ((unused,section (".u_boot_cmd")))
    //即可解释为：实例化一个cmd_tbl_t类型的结构体，并将它保存在.u_boot_cmd段里

在u-boot.1.1.6/include/command.h中，cmd_tbl_t的定义如下

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
    };
    typedef struct cmd_tbl_s cmd_tbl_t;

在u-boot.1.1.6/common中，新增cmd\_hello.c文件

#include <common.h>
    #include <command.h>
    
    int do_hello ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[] )
    {
        printf("this is hello!\n");
        return 0;
    }
    
    U_BOOT_CMD(
        hello, 1, 0, do_hello,
        "hello\t- this cmd is hello\n",
        "this cmd is hello,too\n"
    );

在u-boot.1.1.6/common/Makefile的COBJS后面添加cmd\_hello.o后；在根目录make,烧写；即可出现新增的hello命令

![1424785-20190921153021261-1420687409.png][]

![1424785-20190921153121048-1855414674.png][]

转载于:https://www.cnblogs.com/lzd626/p/11563326.html

[1424785-20190921153021261-1420687409.png]: /images/20230601/84b09e518a854541bd420a0e2aeab950.png
[1424785-20190921153121048-1855414674.png]: /images/20230601/7ab42c833ec24942820d7f5e3577699d.png