/* ethread.c - ethread */

#include 

/*------------------------------------------------------------------------
 * ethread - read an incoming packet on TI AM335X Ethernet
 *------------------------------------------------------------------------
 */
devcall ethread (
                struct  dentry *devptr,
                char    *buf,
                int32   count
        )
{
        struct  ethcblk *ethptr;        /* Ethernet ctl blk ptr */
        struct  eth_a_csreg *csrptr;    /* Ethernet CSR pointer */
        struct  eth_a_rx_desc *rdescptr;/* Rx Desc. pointer     */
        struct  eth_a_rx_desc *prev;    /* Prev Rx desc pointer */
        uint32  retval;                 /* Num of bytes returned*/

        ethptr = ðertab[devptr->dvminor];

        /* Get the pointer to Ethernet CSR */
        csrptr = (struct eth_a_csreg *)ethptr->csr;

        /* Wait for a packet */
        wait(ethptr->isem);

        /* Get pointer to the descriptor */
        rdescptr = (struct eth_a_rx_desc *)ethptr->rxRing +
                                                ethptr->rxHead;

        /* Read the packet length */
        retval = rdescptr->packlen;
        if(retval > count) {
                retval = count;
        }

        /* Copy the packet into user provided buffer */
        memcpy((char *)buf, (char *)rdescptr->buffer, retval);

        /* Initialize the descriptor for next packet */
        rdescptr->stat = ETH_AM335X_RDS_OWN;
        rdescptr->bufoff = 0;
        rdescptr->buflen = ETH_BUF_SIZE;
        rdescptr->packlen = 0;
        rdescptr->next = NULL;

        /* Insert the descriptor into Rx queue */
        prev = (struct eth_a_rx_desc *)csrptr->stateram->rx_hdp[0];
        if(prev == NULL) {
                kprintf("hdp 0, adding %x\n", rdescptr);
                csrptr->stateram->rx_hdp[0] = (uint32)rdescptr;
        }
        else {
                while(prev->next != NULL) {
                        prev = prev->next;
                }
                prev->next = rdescptr;
        }

        /* Increment the head index of rx ring */
        ethptr->rxHead++;
        if(ethptr->rxHead >= ethptr->rxRingSize) {
                ethptr->rxHead = 0;
        }

        return retval;
}