mac_low.c

此文档为采用FPGA实现的以太网MAC层

#include "mac_low.h"



void mac_low_init(void)
{
    Uint8 x;
    Uint16 addr;
    BD_TYPE *bdptr;



    //Initializes the MAC module

    //Setup the mode register for Full duplex (bit 10);
    EMAC_MODE |= 0x00000400;

    //Setup the BD NUM
    EMAC_TXBDNUM = TXBDNUM;

    //Setup IPGT
    EMAC_IPGT = 0x15;


    //mac_clr_rxbd();
    //Loop through and clear RX BD's
    //Evens start at low address and increment up
    for (x=0,addr=EMAC_RX_OFFSET;x<RXBDCOUNT;x++)
    {
       mac_clr_rxbd(x);
       mac_setbdaddr(x++,addr);
       addr += RXBDSIZE;
    }

    //Odds start high and decrement
    for (x=1,addr=EMAC_RAM_SIZE;x<RXBDCOUNT;x++)
    {
       addr -= RXBDSIZE;
       mac_clr_rxbd(x);
       mac_setbdaddr(x++,addr);
    }

    //Set the last BD to wrap
    mac_setwr(RXBDCOUNT-1);
    //mac_setwr(1);



}

//Sets length of TXBD
//Length should be in 16-bit words
void mac_set_len(Uint8 bdnum,Uint16 data_len)
{
    BD_TYPE *bdptr;
    Uint32 word = 0;
    Uint8 *tmpptr;

    tmpptr = (Uint8 *) EMAC_TXBD_PTR;
    tmpptr += bdnum*BD_SIZE;
    //bdptr = (BD_TYPE *) EMAC_RXBD_PTR;
    //bdptr += (Uint8*) bdnum*BD_SIZE;
    bdptr = (BD_TYPE *) tmpptr;


    //Sets the length in the TX BD
    //bdptr = EMAC_TXBD_PTR;

    word = ((data_len*2) & 0xFFFF) << 16;
    //dbg_string((Uint16 *) &word,2);

    //Clear upper 2 bytes first
    bdptr->reg &= ~(0xFFFF0000);

    bdptr->reg |= word;


}

//Clears the RX BD and re-initializes
void mac_clr_rxbd(Uint8 bdnum)
{
    BD_TYPE *bdptr;
    Uint8 *tmpptr;

    //bdptr = (BD_TYPE *) (EMAC_RXBD_PTR+(bdnum*BD_SIZE));
    tmpptr = (Uint8 *) EMAC_RXBD_PTR;
    tmpptr += bdnum*BD_SIZE;
    //bdptr = (BD_TYPE *) EMAC_RXBD_PTR;
    //bdptr += (Uint8*) bdnum*BD_SIZE;
    bdptr = (BD_TYPE *) tmpptr;

    //bdptr->reg = 0xE000;
    bdptr->reg &= ~(0x0fff);
    //bdptr->reg &= ~(0x1FF);
    //bdptr->reg = 0xC000;
    bdptr->reg |= 0xC000;
}

//Sets wrapping on the BD
void mac_setwr(Uint8 bdnum)
{
    BD_TYPE *bdptr;
    Uint8 *tmpptr;

    tmpptr = (Uint8 *) EMAC_RXBD_PTR;
    tmpptr += bdnum*BD_SIZE;
    //bdptr = (BD_TYPE *) EMAC_RXBD_PTR;
    //bdptr += (Uint8*) bdnum*BD_SIZE;
    bdptr = (BD_TYPE *) tmpptr;

    bdptr->reg |= 0x2000;

}

void mac_setbdaddr(Uint8 bdnum,Uint16 address)
{
    BD_TYPE *bdptr;
    Uint8 *tmpptr;

    tmpptr = (Uint8 *) EMAC_RXBD_PTR;
    tmpptr += bdnum*BD_SIZE;
    //bdptr = (BD_TYPE *) EMAC_RXBD_PTR;
    //bdptr += (Uint8*) bdnum*BD_SIZE;
    bdptr = (BD_TYPE *) tmpptr;


    //Setup pointer to point to ram
    bdptr->buffer_address = address;

}

Uint32 mac_getbdaddr(Uint8 bdnum)
{
    BD_TYPE *bdptr;
    Uint8 *tmpptr;
    Uint32 word;
    Uint16 tmpint;

    tmpptr = (Uint8 *) EMAC_RXBD_PTR;
    tmpptr += bdnum*BD_SIZE;
    //bdptr = (BD_TYPE *) EMAC_RXBD_PTR;
    //bdptr += (Uint8*) bdnum*BD_SIZE;
    bdptr = (BD_TYPE *) tmpptr;

    word = bdptr->buffer_address;
    word += EMAC_RAM_PTR;

    return word;
}


void mac_set_address(Uint8 *mac_address)
{
    Uint32 tmpword = 0;

    tmpword = ((mac_address[0] & 0xff) << 8) | (mac_address[1] & 0xff);
    EMAC_MACADDR1 = tmpword;
    tmpword = ((mac_address[2] & 0xff) << 24) | ((mac_address[3] & 0xff) << 16) | ((mac_address[4] & 0xff) << 8) | ((mac_address[5] & 0xff));
    EMAC_MACADDR0 = tmpword;
}

void mac_txen(void)
{
    //Enable the transmitter by setting bit 1
    EMAC_MODE |= 0x00000002;
}

void mac_rxen(void)
{
    //Enable the receiver by setting bit 0
    EMAC_MODE |= 0x00000001;
}

//Clears the RX interrupt
void mac_clr_rxint(void)
{
    EMAC_INT_SRC |= 0x4;
}

//Unmasks the RX interrupt
void mac_rxint_en(void)
{
    EMAC_INT_MASK |= 4;
}

//Masks the RX interrupt
void mac_rxint_dis(void)
{
    EMAC_INT_MASK &= ~4;
}