u-boot中網口處理--軟體部分

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u-boot中DM9000驅動分析

1. CSRs和PHY reg讀寫。

 1 static u16 2 phy_read(int reg) 3 { 4     u16 val; 5  6     /* Fill the phyxcer register into REG_0C */ 7     DM9000_iow(DM9000_EPAR, DM9000_PHY | reg); 8     DM9000_iow(DM9000_EPCR, 0xc);    /* Issue phyxcer read command */ 9     udelay(100);        /* Wait read complete */10     DM9000_iow(DM9000_EPCR, 0x0);    /* Clear phyxcer read command */11     val = (DM9000_ior(DM9000_EPDRH) << 8) | DM9000_ior(DM9000_EPDRL);12 13     /* The read data keeps on REG_0D & REG_0E */14     DM9000_DBG("phy_read(%d): %d\n", reg, val);15     return val;16 }

phy_read

 1 static void 2 phy_write(int reg, u16 value) 3 { 4  5     /* Fill the phyxcer register into REG_0C */ 6     DM9000_iow(DM9000_EPAR, DM9000_PHY | reg); 7  8     /* Fill the written data into REG_0D & REG_0E */ 9     DM9000_iow(DM9000_EPDRL, (value & 0xff));10     DM9000_iow(DM9000_EPDRH, ((value >> 8) & 0xff));11     DM9000_iow(DM9000_EPCR, 0xa);    /* Issue phyxcer write command */12     udelay(500);        /* Wait write complete */13     DM9000_iow(DM9000_EPCR, 0x0);    /* Clear phyxcer write command */14     DM9000_DBG("phy_write(reg:%d, value:%d)\n", reg, value);15 }

phy_write

 1 static u8 2 DM9000_ior(int reg) 3 { 4     u32     val; 5      6     VALIDATE_ADDR_PORT(reg) 7  8     val = *(u16*)DM9000_DATA; 9 10     val &= 0xffff;11     12     return (u8)val;13 }

DM9000_ior

1 static void2 DM9000_iow(int reg, u8 value)3 {4     VALIDATE_ADDR_PORT(reg)5 6     *(u16*)(DM9000_DATA) =     (u16)value;7 }

DM9000_iow

1 #define    VALIDATE_ADDR_PORT(p) 2     if( m_uLastAddressPort != (p) ) 3         { 4             *(u16*)(DM9000_IO)  =(u16)(p);5             m_uLastAddressPort = (p);6         }

VALIDATE_ADDR_PORT

2. 網口收發

 1 int 2 eth_rx(void) 3 { 4     u8 rxbyte, *rdptr = (u8 *) NetRxPackets[0]; 5     int     errors=0; 6     u16        RxLen; 7  8     u32     desc; 9     PDM9000_RX_DESCRIPTOR    pdesc;10 11     DM9000_ior(DM9000_RSR);12     DM9000_ior(DM9000_ROCR);    13 14     for(pdesc=(PDM9000_RX_DESCRIPTOR)&desc;;)15     {16         // probe first byte17         desc = DeviceReadDataWithoutIncrement();    18         DM9000_DBG("1:\tdesc is 0x%x\n",desc);19 20         // check if packet available, 01h means available, 00h means no data21         if(pdesc->bState != 0x01)22         {23             RxLen = 0;24             break;25         }26 27         // get the data descriptor again28         desc = DeviceReadData();29         DM9000_DBG("2:\tdesc is 0x%x\n",desc);        30 31         DM9000_DBG("len is 0x%x\n",pdesc->nLength);                32 33         DeviceReadString(rdptr,pdesc->nLength);34 35         // check status, as specified in DM9000_RXSR,36         // the following bits are error37         // <3> PLE38         // <2> AE39         // <1> CE40         // <0> FOE41         if(pdesc->bStatus & MAKE_MASK4(3,2,1,0))42         {43             errors++;44             continue;45         } // of error happens46 47         RxLen =pdesc->nLength;48         49         break;50     } // of forever read loop51 52     /* Pass to upper layer */53     DM9000_DBG("passing packet to upper layer\n");54     NetReceive(NetRxPackets[0], RxLen);55     return RxLen;56 }

eth_rx

 1 int 2 eth_send(volatile void *packet, int length) 3 { 4     unsigned int loop; 5 #if 0 6     for(loop = 0; loop<length;loop++) 7     { 8         printf("%02x ",*((char *)packet+loop));     9     }10     printf("\n");    11 #endif12     DeviceWriteString((u8*)packet,length);13 14     DM9000_iow(DM9000_TXPLH,HIGH_BYTE(length));15     DM9000_iow(DM9000_TXPLL,LOW_BYTE(length));16         17     // TXCR<0>, issue TX request18     DM9000_iow(DM9000_TCR, MAKE_MASK(0));19 20         21     DM9000_DBG("transmit done\n\n");22     return 0;23 }

eth_send

資料接收時首先比對包頭4個位元組，第一個位元組必須是0x01，第3，4位元組是資料長度（減去開頭的4個位元組）。

接收完資料後再比對第二位元組（DM9000 RSR），確認是否又錯誤發生。

用到的編程技巧是讀取的包頭4個位元組直接賦值給一個u32，最低位元組即為01，高兩位為包長度。

u-boot中網口處理--軟體部分