ethhandler.c

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/* ethhandler.c - ethhandler */

#include <xinu.h>

/*------------------------------------------------------------------------
 * ethhandler - TI AM335X Ethernet Interrupt Handler
 *------------------------------------------------------------------------
 */
interrupt ethhandler (
        uint32  xnum    /* IRQ number   */
    )
{
    struct  eth_a_csreg *csrptr;        /* Ethernet CSR pointer */
    struct  eth_a_tx_desc *tdescptr;    /* Tx desc pointer  */
    struct  eth_a_rx_desc *rdescptr;    /* Rx desc pointer  */
    struct  ethcblk *ethptr = &ethertab[0]; /* Ethernet ctl blk ptr */

    csrptr = (struct eth_a_csreg *)ethptr->csr;

    if(xnum == ETH_AM335X_TXINT) {  /* Transmit interrupt */

        /* Get pointer to first desc in queue   */

        tdescptr = (struct eth_a_tx_desc *)ethptr->txRing +
                            ethptr->txHead;

        /* Defer scheduling until all descs are processed */

        resched_cntl(DEFER_START);

        while(semcount(ethptr->osem) < (int32)ethptr->txRingSize) {

            /* If desc owned by DMA, check if we need to    */
            /* Restart the transmission         */

            if(tdescptr->stat & ETH_AM335X_TDS_OWN) {
                if(csrptr->stateram->tx_hdp[0] == 0) {
                    csrptr->stateram->tx_hdp[0] =
                            (uint32)tdescptr;
                }
                break;
            }

            /* Acknowledge the interrupt    */

            csrptr->stateram->tx_cp[0] = (uint32)tdescptr;

            /* Increment the head index of the queue    */
            /* And go to the next descriptor in queue   */

            ethptr->txHead++;
            tdescptr++;
            if(ethptr->txHead >= ethptr->txRingSize) {
                ethptr->txHead = 0;
                tdescptr = (struct eth_a_tx_desc *)
                            ethptr->txRing;
            }

            /* Signal the output semaphore */

            signal(ethptr->osem);
        }

        /* Acknowledge the transmit interrupt */

        csrptr->cpdma->eoi_vector = 0x2;

        /* Resume rescheduling  */

        resched_cntl(DEFER_STOP);
    }
    else if(xnum == ETH_AM335X_RXINT) { /* Receive interrupt */

        /* Get the pointer to last desc in the queue    */

        rdescptr = (struct eth_a_rx_desc *)ethptr->rxRing +
                            ethptr->rxTail;

        /* Defer scheduling until all descriptors are processed */

        resched_cntl(DEFER_START);

        while(semcount(ethptr->isem) < (int32)ethptr->rxRingSize) {

            /* Check if we need to restart the DMA  */

            if(rdescptr->stat & ETH_AM335X_RDS_OWN) {
                if(csrptr->stateram->rx_hdp[0] == 0) {
                    csrptr->stateram->rx_hdp[0] =
                            (uint32)rdescptr;
                }
                break;
            }

            /* Acknowledge the interrupt    */

            csrptr->stateram->rx_cp[0] = (uint32)rdescptr;

            /* Increment the tail index of the queue    */
            /* And go to the next descriptor in the queue   */

            ethptr->rxTail++;
            rdescptr++;
            if(ethptr->rxTail >= ethptr->rxRingSize) {
                ethptr->rxTail = 0;
                rdescptr = (struct eth_a_rx_desc *)
                            ethptr->rxRing;
            }

            /* Signal the input semaphore   */

            signal(ethptr->isem);
        }

        /* Acknowledge the receive interrupt */

        csrptr->cpdma->eoi_vector = 0x1;

        /* Resume rescheduling  */

        resched_cntl(DEFER_STOP);
    }
}