Linux 下读写PHY寄存器的工具，交叉编译一下就可以使用了。

#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>
 
#define reteck(ret) \ 
		if(ret < 0){ \ 
			printf("%m! \"%s\" : line: %d\n", __func__, __LINE__); \
			goto lab; \ 
		} 
 
#define help() \ 
	printf("mdio:\n"); \ 
	printf("read operation: mdio reg_addr\n"); \
	printf("write operation: mdio reg_addr value\n"); \ 
	printf("For example:\n"); \
	printf("mdio eth0 1\n"); \ 
	printf("mdio eth0 0 0x12\n\n"); \ 
	exit(0); 
 
int sockfd; 
 
int main(int argc, char *argv[]){ 
	if(argc == 1 || !strcmp(argv[1], "-h"))
	{ 
		help(); 
	} 
	struct mii_ioctl_data *mii = NULL; 
	struct ifreq ifr; 
	int ret; 
	memset(&ifr, 0, sizeof(ifr));
	strncpy(ifr.ifr_name, argv[1], IFNAMSIZ - 1);
	sockfd = socket(PF_LOCAL, SOCK_DGRAM, 0);
	reteck(sockfd); //get phy address in smi bus 
	ret = ioctl(sockfd, SIOCGMIIPHY, &ifr); 
	reteck(ret); 
	mii = (struct mii_ioctl_data*)&ifr.ifr_data; 
	if(argc == 3)
	{ 
		mii->reg_num = (uint16_t)strtoul(argv[2], NULL, 0);
		ret = ioctl(sockfd, SIOCGMIIREG, &ifr);
		reteck(ret);
		printf("read phy addr: 0x%x reg: 0x%x value : 0x%x\n", mii->phy_id, mii->reg_num, mii->val_out);
	}
	else if(argc == 4)
	{ 
		mii->reg_num = (uint16_t)strtoul(argv[2], NULL, 0); 
		mii->val_in = (uint16_t)strtoul(argv[3], NULL, 0); 
		ret = ioctl(sockfd, SIOCSMIIREG, &ifr); 
		reteck(ret);
		printf("write phy addr: 0x%x reg: 0x%x value : 0x%x\n", mii->phy_id, mii->reg_num, mii->val_in);
	} 
lab: close(sockfd);
	return 0; 
}

假设编译出来的工具名称为PhyRegTools，那么启用网络灯命令为：
1.切换寄存器页7：PhyRegTools eth0 0x1f 0x7
2.设置19号寄存器: PhyRegTools eth0 0x13 0x3000
然后网口的数据灯就闪烁了。。。