在驱动层，设备树绑定mac与mdio总线的关系。

在Linux应用层，编写测试程序mdio 。代码如下：

如果是写寄存器操作，就传入四个参数./mdio ethX phyId addr value.。

ethX 表示是哪个网卡，如eth0 eth1 。

phyId是 phy的物理地址，一般0x00是广播地址.有些phy 的0x00不是广播地址，如marvell 的88e1512 ID 只能时0x00 0x11，0x00不是88e1512的广播地址。

addr 是phy手册的寄存器地址

value 是phy地址要写入的值

如果是读寄存器操作，就传入三个参数./mdio ethX phyId addr

include <stdio.h>

include <stdlib.h>

include <string.h>

include <linux/mii.h>

include <sys/types.h>

include <sys/socket.h>

include <sys/ioctl.h>

include <net/if.h>

include <linux/sockios.h>

include <linux/types.h>

include <netinet/in.h>

include <unistd.h>

//#include

int main(int argc, char *argv[])
{

int sockfd;
struct mii_ioctl_data *mii = NULL;
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, "eth0", IFNAMSIZ - 1);
sockfd = socket(PF_LOCAL, SOCK_DGRAM, 0);
ioctl(sockfd, SIOCGMIIPHY, &ifr);
mii = (struct mii_ioctl_data*)&ifr.ifr_data;

if(argc == 4)
{
    strncpy(ifr.ifr_name, argv[1], IFNAMSIZ - 1);
    sockfd = socket(PF_LOCAL, SOCK_DGRAM, 0);
    ioctl(sockfd, SIOCGMIIPHY, &ifr);
    mii = (struct mii_ioctl_data*)&ifr.ifr_data;

    mii->phy_id    = (uint16_t)strtoul(argv[2], NULL, 0);
    mii->reg_num    = (uint16_t)strtoul(argv[3], NULL, 0);

    ioctl(sockfd, SIOCGMIIREG, &ifr);

    printf("read --- value : 0x%x", mii->val_out);
}
else if(argc == 5)
{
    strncpy(ifr.ifr_name, argv[1], IFNAMSIZ - 1);
    sockfd = socket(PF_LOCAL, SOCK_DGRAM, 0);
    ioctl(sockfd, SIOCGMIIPHY, &ifr);
    mii = (struct mii_ioctl_data*)&ifr.ifr_data;
    mii->phy_id    = (uint16_t)strtoul(argv[2], NULL, 0);
    mii->reg_num    = (uint16_t)strtoul(argv[3], NULL, 0);
    mii->val_in     = (uint16_t)strtoul(argv[4], NULL, 0);

    ioctl(sockfd, SIOCSMIIREG, &ifr);
}else{
   printf("mdio ethX phyId addr value\n");
}

close(sockfd);



return 0;

}