uboot 启动延时，向kernel传递参数的设置

在uboot的 /uboot/include/configs/xxx.h的文件中

 /* Environment information */

 #define CONFIG_BOOTDELAY        6   // 即uboot启动之后，延迟6妙进行启动kernel

/* 这是uboot向kernel传递的具体参数 */   如果我们可以想往内核中传递另一个参数，可以参照下面的书写方式进行传递

// 例如，下面红色字体部分，是我们要向kernel中增加的传递参数，参照上下的书写格式进行添加，

#define CONFIG_EXTRA_ENV_SETTINGS \
    "loadaddr=0x80200000\0" \
    "rdaddr=0x81000000\0" \
    "usbtty=cdc_acm\0" \
    "console=ttyS2,115200n8\0" \
    "mpurate=600\0" \
    "buddy=none\0"\
    "camera=none\0" \
    "vram=4M\0" \
    "dvimode=800x600MR-16@60\0" \
    "defaultdisplay=dvi\0" \
    "mmcdev=1\0" \
    "mem_size=208M@0x80000000\0" \
    "mmcroot=/dev/mmcblk0p2 rw\0" \
    "mmcrootfstype=ext3 rootwait\0" \
    "nandroot=/dev/mtdblock4 rw\0" \
    "nandrootfstype=jffs2\0" \
    "ramroot=/dev/ram0 rw ramdisk_size=65536 initrd=0x81000000,64M\0" \
    "vram_tt=0\:2M,1\:2M\0" \
    "ramrootfstype=ext2\0" \
    "mmcargs=setenv bootargs console=${console} " \
    "kgdboc=ttyS2,115200 kgdbwait " \
        "mpurate=${mpurate} " \
        "buddy=${buddy} "\
        "camera=${camera} "\
        "vram=${vram} " \
        "omapfb.mode=dvi:${dvimode} " \
        "omapdss.def_disp=${defaultdisplay} " \
        "omapfb.vram=${vram_tt} " \
        "mem=${mem_size} " \
                "root=${mmcroot} " \
        "rootfstype=${mmcrootfstype}\0" \
    "nandargs=setenv bootargs console=${console} " \
        "${optargs} " \
        "mpurate=${mpurate} " \
        "buddy=${buddy} "\
        "camera=${camera} "\
        "vram=${vram} " \
        "omapfb.mode=dvi:${dvimode} " \
        "omapdss.def_disp=${defaultdisplay} " \
        "root=${nandroot} " \
        "rootfstype=${nandrootfstype}\0" \
    "loadramdisk=fatload mmc ${mmcdev} ${rdaddr} ramdisk.gz\0" \
    "loaduimagefat=fatload mmc ${mmcdev} ${loadaddr} uImage\0" \
    "loaduimage=ext2load mmc ${mmcdev}:2 ${loadaddr} /boot/uImage\0" \
    "mmcboot=echo Booting from mmc ...; " \
        "run mmcargs; " \
        "bootm ${loadaddr}\0" \
    "nandboot=echo Booting from nand ...; " \
        "run nandargs; " \
        "nand read ${loadaddr} 280000 400000; " \
        "bootm ${loadaddr}\0" \