以获取fw_version为例，也就是获取ext_CSD[261:254]的值：

kernel/include/linux/mmc/card.h

struct mmc_ext_csd{

+u8 raw_fw_version[8]; /*254 - 8bytes*/

}

kernel/include/linux/mmc/mmc.h

+#define EXT_CSD_FW_VER 254 /* RO 8bytes*/

kernel/drivers/mmc/core/mmc.c

mmc_read_ext_csd()

{

+for(int i=0;i<8;i++)

+card->ext_csd.raw_fw_version[i]=ext_csd[EXT_CSD_FW_VER + i];

}

+MMC_DEV_ATTR(ecsdrev,"%08x%08x%08x%08x%08x%08x%08x%08x",

card->ext_csd.raw_fw_version[0],card->ext_csd.raw_fw_version[1],card->ext_csd.raw_fw_version[2],card->ext_csd.raw_fw_version[3], card->ext_csd.raw_fw_version[4],card->ext_csd.raw_fw_version[5],card->ext_csd.raw_fw_version[6],card->ext_csd.raw_fw_version[7]);

static struct attribute *mmc_std_attrs[] ={

&dev_attr_ecsdrev.attr,

}

添加完成后，可以通过命令来查看：

cat /sys/class/mmc_host/mmc0/mmc0:0001/ecsdrev