RTL8019的使用及分析2

4、驱动代码分析

 

了解网卡的工作流程，分析分析驱动程序是再好不过的方式了。

网上流传的rtl8019as的驱动还是比较多版本的，这里用的是U-boot-1.1.6中的rtl8019as的驱动:

//定义Page的地址#define RTL8019_REG_00 (RTL8019_BASE + 0x00<<1)#define RTL8019_REG_01 (RTL8019_BASE + 0x01<<1)#define RTL8019_REG_02 (RTL8019_BASE + 0x02<<1)#define RTL8019_REG_03 (RTL8019_BASE + 0x03<<1)#define RTL8019_REG_04 (RTL8019_BASE + 0x04<<1)#define RTL8019_REG_05 (RTL8019_BASE + 0x05<<1)#define RTL8019_REG_06 (RTL8019_BASE + 0x06<<1)#define RTL8019_REG_07 (RTL8019_BASE + 0x07<<1)#define RTL8019_REG_08 (RTL8019_BASE + 0x08<<1)#define RTL8019_REG_09 (RTL8019_BASE + 0x09<<1)#define RTL8019_REG_0a (RTL8019_BASE + 0x0a<<1)#define RTL8019_REG_0b (RTL8019_BASE + 0x0b<<1)#define RTL8019_REG_0c (RTL8019_BASE + 0x0c<<1)#define RTL8019_REG_0d (RTL8019_BASE + 0x0d<<1)#define RTL8019_REG_0e (RTL8019_BASE + 0x0e<<1)#define RTL8019_REG_0f (RTL8019_BASE + 0x0f<<1)#define RTL8019_REG_10 (RTL8019_BASE + 0x10<<1)#define RTL8019_REG_1f (RTL8019_BASE + 0x1f<<1) //将物理寄存器映射为各种功能寄存器，方便理解#define RTL8019_COMMAND RTL8019_REG_00 //CR寄存器#define RTL8019_PAGESTART RTL8019_REG_01 //接收缓冲启始位置#define RTL8019_PAGESTOP RTL8019_REG_02 //接收缓冲结束位置#define RTL8019_BOUNDARY RTL8019_REG_03 //Boundary寄存器#define RTL8019_TRANSMITSTATUS RTL8019_REG_04 //传输状态寄存器#define RTL8019_TRANSMITPAGE RTL8019_REG_04 //传输开始page#define RTL8019_TRANSMITBYTECOUNT0 RTL8019_REG_05 //传输字节数低8位#define RTL8019_NCR RTL8019_REG_05 //冲突次数#define RTL8019_TRANSMITBYTECOUNT1 RTL8019_REG_06 //传输字节数高8位#define RTL8019_INTERRUPTSTATUS RTL8019_REG_07 //中断状态寄存器#define RTL8019_CURRENT RTL8019_REG_07 //CURRENT寄存器#define RTL8019_REMOTESTARTADDRESS0 RTL8019_REG_08 //接收数据起始地址低8位#define RTL8019_CRDMA0 RTL8019_REG_08#define RTL8019_REMOTESTARTADDRESS1 RTL8019_REG_09 //接收数据起始地址高8位#define RTL8019_CRDMA1 RTL8019_REG_09#define RTL8019_REMOTEBYTECOUNT0 RTL8019_REG_0a //接收数据字节大小低8位#define RTL8019_REMOTEBYTECOUNT1 RTL8019_REG_0b //接收数据字节大小高8位#define RTL8019_RECEIVESTATUS RTL8019_REG_0c //接收状态寄存器#define RTL8019_RECEIVECONFIGURATION RTL8019_REG_0c //接收配置寄存器#define RTL8019_TRANSMITCONFIGURATION RTL8019_REG_0d //发送接收寄存器#define RTL8019_FAE_TALLY RTL8019_REG_0d#define RTL8019_DATACONFIGURATION RTL8019_REG_0e //数据配置寄存器#define RTL8019_CRC_TALLY RTL8019_REG_0e#define RTL8019_INTERRUPTMASK RTL8019_REG_0f //中断屏蔽寄存器#define RTL8019_MISS_PKT_TALLY RTL8019_REG_0f#define RTL8019_PHYSICALADDRESS0 RTL8019_REG_01 //MAC地址0#define RTL8019_PHYSICALADDRESS1 RTL8019_REG_02#define RTL8019_PHYSICALADDRESS2 RTL8019_REG_03#define RTL8019_PHYSICALADDRESS3 RTL8019_REG_04#define RTL8019_PHYSICALADDRESS4 RTL8019_REG_05#define RTL8019_PHYSICALADDRESS5 RTL8019_REG_06#define RTL8019_MULTIADDRESS0 RTL8019_REG_08 //多播地址配置#define RTL8019_MULTIADDRESS1 RTL8019_REG_09#define RTL8019_MULTIADDRESS2 RTL8019_REG_0a#define RTL8019_MULTIADDRESS3 RTL8019_REG_0b#define RTL8019_MULTIADDRESS4 RTL8019_REG_0c#define RTL8019_MULTIADDRESS5 RTL8019_REG_0d#define RTL8019_MULTIADDRESS6 RTL8019_REG_0e#define RTL8019_MULTIADDRESS7 RTL8019_REG_0f#define RTL8019_DMA_DATA RTL8019_REG_10 //DMA传输寄存器(读出/写入)#define RTL8019_RESET RTL8019_REG_1f //NIC复位寄存器 //定义一些用来设置寄存器的值#define RTL8019_PAGE0 0x22 //0010 0010#define RTL8019_PAGE1 0x62 //0110 0010#define RTL8019_PAGE0DMAWRITE 0x12 //0001 0010#define RTL8019_PAGE2DMAWRITE 0x92 //1001 0010#define RTL8019_REMOTEDMAWR 0x12 //0001 0010#define RTL8019_REMOTEDMARD 0x0A //0000 1010#define RTL8019_ABORTDMAWR 0x32 //0011 0010#define RTL8019_ABORTDMARD 0x2A //0010 1010#define RTL8019_PAGE0STOP 0x21 //0010 0001#define RTL8019_PAGE1STOP 0x61 //0110 0001#define RTL8019_TRANSMIT 0x26 //0010 0110#define RTL8019_TXINPROGRESS 0x04 //0000 0100#define RTL8019_SEND 0x1A //0001 1010 #define RTL8019_PSTART 0x4c //0100 1100#define RTL8019_PSTOP 0x80 //1000 0000#define RTL8019_TPSTART 0x40 //0100 0000 static void eth_reset (void){ unsigned char ucTemp; /* reset NIC */ //向reset寄存器中写入任何值就可以完成NIC的reset ucTemp = get_reg (RTL8019_RESET); put_reg (RTL8019_RESET, ucTemp); //清除所有的中断位 put_reg (RTL8019_INTERRUPTSTATUS, 0xff); udelay (2000); /* wait for 2ms */} int eth_init (bd_t * bd){ //初始化NIC eth_reset (); put_reg (RTL8019_COMMAND, RTL8019_PAGE0STOP);//选择page0,停机状态 put_reg (RTL8019_DATACONFIGURATION, 0x48);//设置为loopback模式，且DMA为8位模式 put_reg (RTL8019_REMOTEBYTECOUNT0, 0x00);//清除接收数据寄存器 put_reg (RTL8019_REMOTEBYTECOUNT1, 0x00); put_reg (RTL8019_RECEIVECONFIGURATION, 0x00); //瞎写 put_reg (RTL8019_TRANSMITPAGE, RTL8019_TPSTART);//传输起始page设为Page40 put_reg (RTL8019_TRANSMITCONFIGURATION, 0x02);//传输配置，loopback模式(跟DCR配对，均需设置) put_reg (RTL8019_PAGESTART, RTL8019_PSTART);//接收数据起始page设置为Page4c put_reg (RTL8019_BOUNDARY, RTL8019_PSTART);//Boundary初始化为page4c put_reg (RTL8019_PAGESTOP, RTL8019_PSTOP);//接收数据边界页为Page80 put_reg (RTL8019_INTERRUPTSTATUS, 0xff);//清除所有中断寄存位 put_reg (RTL8019_INTERRUPTMASK, 0x11); //只允许第0位和第4位中断 put_reg (RTL8019_COMMAND, RTL8019_PAGE1STOP);//选择page1,停机状态 put_reg (RTL8019_PHYSICALADDRESS0, bd->bi_enetaddr[0]);//设置MAC地址 put_reg (RTL8019_PHYSICALADDRESS1, bd->bi_enetaddr[1]); put_reg (RTL8019_PHYSICALADDRESS2, bd->bi_enetaddr[2]); put_reg (RTL8019_PHYSICALADDRESS3, bd->bi_enetaddr[3]); put_reg (RTL8019_PHYSICALADDRESS4, bd->bi_enetaddr[4]); put_reg (RTL8019_PHYSICALADDRESS5, bd->bi_enetaddr[5]); put_reg (RTL8019_MULTIADDRESS0, 0x00);//设置多播地址(设置的值是什么意思呢？？) put_reg (RTL8019_MULTIADDRESS1, 0x00); put_reg (RTL8019_MULTIADDRESS2, 0x00); put_reg (RTL8019_MULTIADDRESS3, 0x00); put_reg (RTL8019_MULTIADDRESS4, 0x00); put_reg (RTL8019_MULTIADDRESS5, 0x00); put_reg (RTL8019_MULTIADDRESS6, 0x00); put_reg (RTL8019_MULTIADDRESS7, 0x00); put_reg (RTL8019_CURRENT, RTL8019_PSTART);//设置CURRENT寄存器为Page4c put_reg (RTL8019_COMMAND, RTL8019_PAGE0);//选择Page0,且NIC开机(处于开机状态，使其能够接收数据) put_reg (RTL8019_TRANSMITCONFIGURATION, 0xe0);//设置传输模式为1110 0000 //正常模式(非loopback模式),CRC使能 return 0;} static unsigned char nic_to_pc (void){//返回接收操作完成之后的CURRENT寄存器值 //该函数完成的功能是从boundary寄存器中存储的地址开始接收一帧的数据 unsigned char rec_head_status; unsigned char next_packet_pointer; unsigned char packet_length0; unsigned char packet_length1; unsigned short rxlen = 0; unsigned int i = 4; unsigned char current_point; unsigned char *addr; /* * The RTL8019's first 4B is packet status,page of next packet * and packet length(2B).So we receive the fist 4B. */ //rtl8019as的帧的头4Byte如上所述： //第一字节为status //第二字节为下一个帧的起始Page //第3,4字节为本帧的长度，以字节为单位 put_reg (RTL8019_REMOTESTARTADDRESS1, get_reg (RTL8019_BOUNDARY)); put_reg (RTL8019_REMOTESTARTADDRESS0, 0x00);//因为实际接收地址是boundary<<8,所以低8位地址恒定为0 put_reg (RTL8019_REMOTEBYTECOUNT1, 0x00); put_reg (RTL8019_REMOTEBYTECOUNT0, 0x04);//从接收缓冲区中接收4字节的数据 put_reg (RTL8019_COMMAND, RTL8019_REMOTEDMARD);//在CR中设置接收位为001(Remote Read) rec_head_status = get_reg (RTL8019_DMA_DATA);//读第一个字节 next_packet_pointer = get_reg (RTL8019_DMA_DATA);//读第二个字节 packet_length0 = get_reg (RTL8019_DMA_DATA);//第三个字节 packet_length1 = get_reg (RTL8019_DMA_DATA);//第四个字节 put_reg (RTL8019_COMMAND, RTL8019_PAGE0);//设置CR为Page0 /*Packet length is in two 8bit registers */ rxlen = packet_length1; rxlen = (((rxlen < < 8) & 0xff00) + packet_length0); rxlen -= 4; if (rxlen > PKTSIZE_ALIGN + PKTALIGN) printf ("packet too big!/n"); /*Receive the packet */ put_reg (RTL8019_REMOTESTARTADDRESS0, 0x04);//配置DMA的读取起始地址(减去了4个字节) put_reg (RTL8019_REMOTESTARTADDRESS1, get_reg (RTL8019_BOUNDARY)); put_reg (RTL8019_REMOTEBYTECOUNT0, (rxlen & 0xff));//配置DAM读取长度 put_reg (RTL8019_REMOTEBYTECOUNT1, ((rxlen >> 8) & 0xff)); put_reg (RTL8019_COMMAND, RTL8019_REMOTEDMARD);//设置CR为READ状态 //这里是8位DMA的情况，16位DMA的情况需要做调整,每次能够读出16位的数据 for (addr = (unsigned char *) NetRxPackets[0], i = rxlen; i > 0; i--) *addr++ = get_reg (RTL8019_DMA_DATA); /* Pass the packet up to the protocol layers. */ NetReceive (NetRxPackets[0], rxlen);//将接收到的数据交给上层协议处理 while (!(get_reg (RTL8019_INTERRUPTSTATUS)) & 0x40); /* wait for the op. */ //等待DMA操作结束(RDC位被自动置位的时候表示DMA操作结束) /* * To test whether the packets are all received,get the * location of current point */ put_reg (RTL8019_COMMAND, RTL8019_PAGE1); current_point = get_reg (RTL8019_CURRENT); put_reg (RTL8019_COMMAND, RTL8019_PAGE0); put_reg (RTL8019_BOUNDARY, next_packet_pointer);//将下一帧的起始页数写入到boundary中 //这里难道不需要考虑boundary>80的情况吗？？？？ return current_point;} /* Get a data block via Ethernet */extern int eth_rx (void){ unsigned char temp, current_point; put_reg (RTL8019_COMMAND, RTL8019_PAGE0);//选取Page0,开机状态 while (1) { temp = get_reg (RTL8019_INTERRUPTSTATUS); if (temp & 0x90) { /*中断寄存器为90表示接收数据太快，接收缓冲被用完了，此时由于循环RAM的缘故,CURRENT=BOUNDARY*/ put_reg (RTL8019_COMMAND, RTL8019_PAGE0STOP);//停机 udelay (2000); put_reg (RTL8019_REMOTEBYTECOUNT0, 0); put_reg (RTL8019_REMOTEBYTECOUNT1, 0); put_reg (RTL8019_TRANSMITCONFIGURATION, 2);//进入内部loopback模式 do { //反复读取缓冲中的值，直到boundary==current(注意这时current_point是不变的!!) current_point = nic_to_pc (); } while (get_reg (RTL8019_BOUNDARY) != current_point); put_reg (RTL8019_TRANSMITCONFIGURATION, 0xe0);//推出loopback模式，设置传输配置寄存器为普通模式 } if (temp & 0x1) {//如果有帧被顺利的接收到，会自动给bit0置位 /*packet received */ do { //反复读取直到NIC收到的数据全部被CPU接收 put_reg (RTL8019_INTERRUPTSTATUS, 0x01);//清除bit0 current_point = nic_to_pc (); } while (get_reg (RTL8019_BOUNDARY) != current_point);//这个条件对么？还是应该用burndary+1 == current_point来判断？？？ } if (!(temp & 0x1))//如果没有数据收到则退出 return 0; /* done and exit. */ }} /* Send a data block via Ethernet.发送 */extern int eth_send (volatile void *packet, int length){ volatile unsigned char *p; unsigned int pn; pn = length; p = (volatile unsigned char *) packet; while (get_reg (RTL8019_COMMAND) == RTL8019_TRANSMIT);//等待上一次传输结束 put_reg (RTL8019_REMOTESTARTADDRESS0, 0);//设置传输起始地址 put_reg (RTL8019_REMOTESTARTADDRESS1, RTL8019_TPSTART); put_reg (RTL8019_REMOTEBYTECOUNT0, (pn & 0xff));//设置传输长度 put_reg (RTL8019_REMOTEBYTECOUNT1, ((pn >> 8) & 0xff)); put_reg (RTL8019_COMMAND, RTL8019_REMOTEDMAWR);//标明处于WRITE状态,TPX为0 while (pn > 0) { put_reg (RTL8019_DMA_DATA, *p++); pn--; } pn = length; //如果数据长度小于60个字节时，则自动以0补全 while (pn < 60) { /*Padding */ put_reg (RTL8019_DMA_DATA, 0); pn++; } while (!(get_reg (RTL8019_INTERRUPTSTATUS)) & 0x40);//等待DMA操作结束(发送结束) put_reg (RTL8019_INTERRUPTSTATUS, 0x40);清除相应中断位 put_reg (RTL8019_TRANSMITPAGE, RTL8019_TPSTART);复位传输起始page put_reg (RTL8019_TRANSMITBYTECOUNT0, (pn & 0xff));设置传输字节大小 put_reg (RTL8019_TRANSMITBYTECOUNT1, ((pn >> 8 & 0xff))); put_reg (RTL8019_COMMAND, RTL8019_TRANSMIT);//哦，恍然大悟 //此处是启动NIC通过网卡向外发送数据，上面的REMOTEDMAWR是使NIC进入DMA状态，以便从CPU传数据到发送缓冲中去。 return 0;}

5、驱动流程总结

 

上面简单的分析了一下在U-boot-1.1.6中的rtl8019as的驱动程序。需要注意的是，这个驱动程序是针对8位DMA的，每次的读写都是一个BYTE.RTL8019AS还支持16位DMA模式，如果使用的是这个模式的话，就需要修改驱动程序了，因为每次DMA的读写单位都是2BYTE.其他还需要注意的是寄存器的地址问题。
下面来稍稍总结一下rtl8019as驱动的工作流程。
eth_init:初始化NIC
A,首先向reset寄存器中写入任意的值，使NIC复位
1,设置CR,设置停机状态位
2,设置DMA模式(8位/16位)
3，传输模式设置为loopback模式
4,配置接收缓冲范围和发送缓冲范围
5,清除中断寄存器位并使能一些中断
6,设置本机的MAC地址
7,设置本机的多播地址
8,配置BOUNDARY寄存器和CURRENT寄存器的初始值(发送缓冲的首地址)
9,置CR为开机模式
10,置传输模式为normal模式

nic_to_pc(读取一帧数据):
将boundary值写入REMOTESTARTADDR
设置REMOTECOUNT为4，然后读取4个字节(rtl8019as的帧头长度)
根据帧头中读到的帧状态，帧长度，下一帧的页地址来读取RAM中的本帧数据
将数据交由上层协议处理
将得到的下一帧的起始页数写入boundary寄存器

eth_rx(读取RAM中接收到的数据):
1,读取中断状态寄存器，并判断其值。
a)当中断状态为RAM溢出位被置位时。
2,此时将NIC设置为停机状态(不接收数据)且设为内部loopback模式。
3,反复调用nic_to_pc一帧一帧的读取数据，直到current和boundary值相等。
4,退出内部loopback模式
b)当中断位表示帧被正确的接收时。
2,反复调用nic_to_pc一帧帧的读取数据，直到current和boundary值相等(此时已无数据所能读)
c)如果没有数据收到
2,退出

eth_send(发送数据):
1,轮询CR寄存器的状态，等待DMA传输的结束
2,在REMOTESTARTADDR中设置传输的起始地址
3,在REMOTEBYTECOUNT中设置传输的长度
4,将CR设置为remote write模式
5,循环将需要发送的数据写入RAM(不够60个字节则用0补全)
6,等待DMA操作完成(轮询中断状态寄存器)
7,清除中断状态寄存器
8,在TRANSMITPAGE中写入初始page
9,在TRANSMITBYTECOUNT中写入传输长度
10,设置CR，启动数据发送