ethernet.c

STR71X系列ARM微控制器原理与实践配套光盘

/*
 *
 *	NIC(CS8900A)驱动模块
 *
 */

#include "Ethernet.h"

// 物理地址，默认为22-44-66-88-AA-CC，可在初始化NIC前改写
u16 local_eth_addr[3] = {0x4422, 0x8866, 0xCCAA};

// 从NIC端口输入
inline u16 NIC_InPort(u16 reg)
{
	ETH_Addr_Port = reg;
	return ETH_Data_Port;
}

// 向NIC端口输出
inline void NIC_OutPort(u16 reg, u16 x)
{
	ETH_Addr_Port = reg;
	ETH_Data_Port = x;
}

// 发送帧请求
inline void RequestSend(u16 FrameSize)
{
	ETH_TX_CMD_Port = TX_START_ALL_BYTES;
	ETH_TX_LEN_Port = FrameSize;
}

// 初始化NIC
int NIC_Init(void)
{
	u32 t;

	// 配置STR71x的外部片选信号引脚
	GPIO_Config(GPIO2, 0x000F, GPIO_AF_PP);

	// 使能外部存储器BANK2(CS8900A)
	EMI_Config(2, EMI_ENABLE | EMI_WAITSTATE(15) | EMI_SIZE_16);

	// 软复位并初始化CS8900A（详见CS8900A数据手册）
	NIC_OutPort(PP_SelfCTL, POWER_ON_RESET);

	t = ETH_Port(1);
	t = ETH_Port(0);
	t = ETH_Port(1);

	for(t = 0x1000; t && !(NIC_InPort(PP_SelfST) & INIT_DONE); t--);
	if(!t)
		return -1;

	NIC_OutPort(PP_IA + 0, local_eth_addr[0]);
	NIC_OutPort(PP_IA + 2, local_eth_addr[1]);
	NIC_OutPort(PP_IA + 4, local_eth_addr[2]);

	NIC_OutPort(PP_RxCTL, RX_OK_ACCEPT | RX_IA_ACCEPT | RX_BROADCAST_ACCEPT);
	NIC_OutPort(PP_LineCTL, SERIAL_RX_ON | SERIAL_TX_ON);
	return 0;
}

// 收包
int NIC_RecvPack(u16 *buf)
{
	int stat = NIC_InPort(PP_RxEvent);
	if((stat & RX_OK) && (stat & (RX_IA | RX_BROADCAST)))
	{
		int len, i;

		stat = ETH_RX_Frame_Port;
		len = ETH_RX_Frame_Port;

		if(len < 60 || len > 1514)
			return -1;

		for(i = 0; i < len; i += 2)
			*buf++ = ETH_RX_Frame_Port;
		return len;
	}
	return 0;
}

// 发包
int NIC_SendPack(u16 *buf, int len)
{
	if(!(NIC_InPort(PP_LineST) & LINK_OK))
		return -1;

	if(len < 60)
		len = 60;

	RequestSend(len);
	while(!(NIC_InPort(PP_BusST) & READY_FOR_TX_NOW))
		NIC_OutPort(PP_RxCFG, SKIP_1 | RX_OK_ENBL);

	if(NIC_InPort(PP_BusST) & READY_FOR_TX_NOW)
	{
		int i;
		for(i = 0; i < len; i += 2)
			ETH_TX_Frame_Port = *buf++;
	}
	return 0;
}