lmc_main.c

linux-2.6.15.6

         *  - Transmit underflow         CSR5<5>
         *  - Transmit Receiver buffer unavailable CSR5<7>
         *  - Receive process stopped    CSR5<8>
         *  - Receive watchdog timeout   CSR5<9>
         *  - Early transmit interrupt   CSR5<10>
         *
         * Is this really right? Should we do a running reset for jabber?
         * (being a WAN card and all)
         */
        if (csr & TULIP_STS_ABNRMLINTR){
            lmc_running_reset (dev);
            break;
        }
        
        if (csr & TULIP_STS_RXINTR){
            lmc_trace(dev, "rx interrupt");
            lmc_rx (dev);
            
        }
        if (csr & (TULIP_STS_TXINTR | TULIP_STS_TXNOBUF | TULIP_STS_TXSTOPPED)) {

	    int		n_compl = 0 ;
            /* reset the transmit timeout detection flag -baz */
            sc->stats.tx_NoCompleteCnt = 0;

            badtx = sc->lmc_taint_tx;
            i = badtx % LMC_TXDESCS;

            while ((badtx < sc->lmc_next_tx)) {
                stat = sc->lmc_txring[i].status;

                LMC_EVENT_LOG (LMC_EVENT_XMTINT, stat,
						 sc->lmc_txring[i].length);
                /*
                 * If bit 31 is 1 the tulip owns it break out of the loop
                 */
                if (stat & 0x80000000)
                    break;

		n_compl++ ;		/* i.e., have an empty slot in ring */
                /*
                 * If we have no skbuff or have cleared it
                 * Already continue to the next buffer
                 */
                if (sc->lmc_txq[i] == NULL)
                    continue;

                /*
                 * Check the total error summary to look for any errors
                 */
                if (stat & 0x8000) {
                    sc->stats.tx_errors++;
                    if (stat & 0x4104)
                        sc->stats.tx_aborted_errors++;
                    if (stat & 0x0C00)
                        sc->stats.tx_carrier_errors++;
                    if (stat & 0x0200)
                        sc->stats.tx_window_errors++;
                    if (stat & 0x0002)
                        sc->stats.tx_fifo_errors++;
                }
                else {
                    
                    sc->stats.tx_bytes += sc->lmc_txring[i].length & 0x7ff;
                    
                    sc->stats.tx_packets++;
                }
                
                //                dev_kfree_skb(sc->lmc_txq[i]);
                dev_kfree_skb_irq(sc->lmc_txq[i]);
                sc->lmc_txq[i] = NULL;

                badtx++;
                i = badtx % LMC_TXDESCS;
            }

            if (sc->lmc_next_tx - badtx > LMC_TXDESCS)
            {
                printk ("%s: out of sync pointer\n", dev->name);
                badtx += LMC_TXDESCS;
            }
            LMC_EVENT_LOG(LMC_EVENT_TBUSY0, n_compl, 0);
            sc->lmc_txfull = 0;
            netif_wake_queue(dev);
            sc->stats.tx_tbusy0++ ;


#ifdef DEBUG
            sc->stats.dirtyTx = badtx;
            sc->stats.lmc_next_tx = sc->lmc_next_tx;
            sc->stats.lmc_txfull = sc->lmc_txfull;
#endif
            sc->lmc_taint_tx = badtx;

            /*
             * Why was there a break here???
             */
        }			/* end handle transmit interrupt */

        if (csr & TULIP_STS_SYSERROR) {
            u32 error;
            printk (KERN_WARNING "%s: system bus error csr: %#8.8x\n", dev->name, csr);
            error = csr>>23 & 0x7;
            switch(error){
            case 0x000:
                printk(KERN_WARNING "%s: Parity Fault (bad)\n", dev->name);
                break;
            case 0x001:
                printk(KERN_WARNING "%s: Master Abort (naughty)\n", dev->name);
                break;
            case 0x010:
                printk(KERN_WARNING "%s: Target Abort (not so naughty)\n", dev->name);
                break;
            default:
                printk(KERN_WARNING "%s: This bus error code was supposed to be reserved!\n", dev->name);
            }
            lmc_dec_reset (sc);
            lmc_reset (sc);
            LMC_EVENT_LOG(LMC_EVENT_RESET1, LMC_CSR_READ (sc, csr_status), 0);
            LMC_EVENT_LOG(LMC_EVENT_RESET2,
                          lmc_mii_readreg (sc, 0, 16),
                          lmc_mii_readreg (sc, 0, 17));

        }

        
        if(max_work-- <= 0)
            break;
        
        /*
         * Get current csr status to make sure
         * we've cleared all interrupts
         */
        csr = LMC_CSR_READ (sc, csr_status);
    }				/* end interrupt loop */
    LMC_EVENT_LOG(LMC_EVENT_INT, firstcsr, csr);

lmc_int_fail_out:

    spin_unlock(&sc->lmc_lock);

    lmc_trace(dev, "lmc_interrupt out");
    return IRQ_RETVAL(handled);
}

static int lmc_start_xmit (struct sk_buff *skb, struct net_device *dev) /*fold00*/
{
    lmc_softc_t *sc;
    u32 flag;
    int entry;
    int ret = 0;
    unsigned long flags;

    lmc_trace(dev, "lmc_start_xmit in");

    sc = dev->priv;

    spin_lock_irqsave(&sc->lmc_lock, flags);

    /* normal path, tbusy known to be zero */

    entry = sc->lmc_next_tx % LMC_TXDESCS;

    sc->lmc_txq[entry] = skb;
    sc->lmc_txring[entry].buffer1 = virt_to_bus (skb->data);

    LMC_CONSOLE_LOG("xmit", skb->data, skb->len);

#ifndef GCOM
    /* If the queue is less than half full, don't interrupt */
    if (sc->lmc_next_tx - sc->lmc_taint_tx < LMC_TXDESCS / 2)
    {
        /* Do not interrupt on completion of this packet */
        flag = 0x60000000;
        netif_wake_queue(dev);
    }
    else if (sc->lmc_next_tx - sc->lmc_taint_tx == LMC_TXDESCS / 2)
    {
        /* This generates an interrupt on completion of this packet */
        flag = 0xe0000000;
        netif_wake_queue(dev);
    }
    else if (sc->lmc_next_tx - sc->lmc_taint_tx < LMC_TXDESCS - 1)
    {
        /* Do not interrupt on completion of this packet */
        flag = 0x60000000;
        netif_wake_queue(dev);
    }
    else
    {
        /* This generates an interrupt on completion of this packet */
        flag = 0xe0000000;
        sc->lmc_txfull = 1;
        netif_stop_queue(dev);
    }
#else
    flag = LMC_TDES_INTERRUPT_ON_COMPLETION;

    if (sc->lmc_next_tx - sc->lmc_taint_tx >= LMC_TXDESCS - 1)
    {				/* ring full, go busy */
        sc->lmc_txfull = 1;
        netif_stop_queue(dev);
        sc->stats.tx_tbusy1++ ;
        LMC_EVENT_LOG(LMC_EVENT_TBUSY1, entry, 0);
    }
#endif


    if (entry == LMC_TXDESCS - 1)	/* last descriptor in ring */
	flag |= LMC_TDES_END_OF_RING;	/* flag as such for Tulip */

    /* don't pad small packets either */
    flag = sc->lmc_txring[entry].length = (skb->len) | flag |
						sc->TxDescriptControlInit;

    /* set the transmit timeout flag to be checked in
     * the watchdog timer handler. -baz
     */

    sc->stats.tx_NoCompleteCnt++;
    sc->lmc_next_tx++;

    /* give ownership to the chip */
    LMC_EVENT_LOG(LMC_EVENT_XMT, flag, entry);
    sc->lmc_txring[entry].status = 0x80000000;

    /* send now! */
    LMC_CSR_WRITE (sc, csr_txpoll, 0);

    dev->trans_start = jiffies;

    spin_unlock_irqrestore(&sc->lmc_lock, flags);

    lmc_trace(dev, "lmc_start_xmit_out");
    return ret;
}


static int lmc_rx (struct net_device *dev) /*fold00*/
{
    lmc_softc_t *sc;
    int i;
    int rx_work_limit = LMC_RXDESCS;
    unsigned int next_rx;
    int rxIntLoopCnt;		/* debug -baz */
    int localLengthErrCnt = 0;
    long stat;
    struct sk_buff *skb, *nsb;
    u16 len;

    lmc_trace(dev, "lmc_rx in");

    sc = dev->priv;

    lmc_led_on(sc, LMC_DS3_LED3);

    rxIntLoopCnt = 0;		/* debug -baz */

    i = sc->lmc_next_rx % LMC_RXDESCS;
    next_rx = sc->lmc_next_rx;

    while (((stat = sc->lmc_rxring[i].status) & LMC_RDES_OWN_BIT) != DESC_OWNED_BY_DC21X4)
    {
        rxIntLoopCnt++;		/* debug -baz */
        len = ((stat & LMC_RDES_FRAME_LENGTH) >> RDES_FRAME_LENGTH_BIT_NUMBER);
        if ((stat & 0x0300) != 0x0300) {  /* Check first segment and last segment */
            if ((stat & 0x0000ffff) != 0x7fff) {
                /* Oversized frame */
                sc->stats.rx_length_errors++;
                goto skip_packet;
            }
        }

        if(stat & 0x00000008){ /* Catch a dribbling bit error */
            sc->stats.rx_errors++;
            sc->stats.rx_frame_errors++;
            goto skip_packet;
        }


        if(stat & 0x00000004){ /* Catch a CRC error by the Xilinx */
            sc->stats.rx_errors++;
            sc->stats.rx_crc_errors++;
            goto skip_packet;
        }


        if (len > LMC_PKT_BUF_SZ){
            sc->stats.rx_length_errors++;
            localLengthErrCnt++;
            goto skip_packet;
        }

        if (len < sc->lmc_crcSize + 2) {
            sc->stats.rx_length_errors++;
            sc->stats.rx_SmallPktCnt++;
            localLengthErrCnt++;
            goto skip_packet;
        }

        if(stat & 0x00004000){
            printk(KERN_WARNING "%s: Receiver descriptor error, receiver out of sync?\n", dev->name);
        }

        len -= sc->lmc_crcSize;

        skb = sc->lmc_rxq[i];

        /*
         * We ran out of memory at some point
         * just allocate an skb buff and continue.
         */
        
        if(skb == 0x0){
            nsb = dev_alloc_skb (LMC_PKT_BUF_SZ + 2);
            if (nsb) {
                sc->lmc_rxq[i] = nsb;
                nsb->dev = dev;
                sc->lmc_rxring[i].buffer1 = virt_to_bus (nsb->tail);
            }
            sc->failed_recv_alloc = 1;
            goto skip_packet;
        }
        
        dev->last_rx = jiffies;
        sc->stats.rx_packets++;
        sc->stats.rx_bytes += len;

        LMC_CONSOLE_LOG("recv", skb->data, len);

        /*
         * I'm not sure of the sanity of this
         * Packets could be arriving at a constant
         * 44.210mbits/sec and we're going to copy
         * them into a new buffer??
         */
        
        if(len > (LMC_MTU - (LMC_MTU>>2))){ /* len > LMC_MTU * 0.75 */
            /*
             * If it's a large packet don't copy it just hand it up
             */
        give_it_anyways:

            sc->lmc_rxq[i] = NULL;
            sc->lmc_rxring[i].buffer1 = 0x0;

            skb_put (skb, len);
            skb->protocol = lmc_proto_type(sc, skb);
            skb->protocol = htons(ETH_P_WAN_PPP);
            skb->mac.raw = skb->data;
//            skb->nh.raw = skb->data;
            skb->dev = dev;
            lmc_proto_netif(sc, skb);

            /*
             * This skb will be destroyed by the upper layers, make a new one
             */
            nsb = dev_alloc_skb (LMC_PKT_BUF_SZ + 2);
            if (nsb) {
                sc->lmc_rxq[i] = nsb;
                nsb->dev = dev;
                sc->lmc_rxring[i].buffer1 = virt_to_bus (nsb->tail);
                /* Transferred to 21140 below */
            }
            else {
                /*
                 * We've run out of memory, stop trying to allocate
                 * memory and exit the interrupt handler
                 *
                 * The chip may run out of receivers and stop
                 * in which care we'll try to allocate the buffer
                 * again.  (once a second)
                 */
                sc->stats.rx_BuffAllocErr++;
                LMC_EVENT_LOG(LMC_EVENT_RCVINT, stat, len);
                sc->failed_recv_alloc = 1;
                goto skip_out_of_mem;
            }
        }
        else {
            nsb = dev_alloc_skb(len);
            if(!nsb) {
                goto give_it_anyways;
            }
            memcpy(skb_put(nsb, len), skb->data, len);
            
            nsb->protocol = lmc_proto_type(sc, skb);
            nsb->mac.raw = nsb->data;
//            nsb->nh.raw = nsb->data;
            nsb->dev = dev;
            lmc_proto_netif(sc, nsb);
        }

    skip_packet:
        LMC_EVENT_LOG(LMC_EVENT_RCVINT, stat, len);
        sc->lmc_rxring[i].status = DESC_OWNED_BY_DC21X4;

        sc->lmc_next_rx++;
        i = sc->lmc_next_rx % LMC_RXDESCS;
        rx_work_limit--;
        if (rx_work_limit < 0)
            break;
    }

    /* detect condition for LMC1000 where DSU cable attaches and fills
     * descriptors with bogus packets
     *
    if (localLengthErrCnt > LMC_RXDESCS - 3) {
        sc->stats.rx_BadPktSurgeCnt++;
        LMC_EVENT_LOG(LMC_EVENT_BADPKTSURGE,
                      localLengthErrCnt,
                      sc->stats.rx_BadPktSurgeCnt);
    } */

    /* save max count of receive descriptors serviced */
    if (rxIntLoopCnt > sc->stats.rxIntLoopCnt) {
        sc->stats.rxIntLoopCnt = rxIntLoopCnt;	/* debug -baz */
    }

#ifdef DEBUG
    if (rxIntLoopCnt == 0)
    {
        for (i = 0; i < LMC_RXDESCS; i++)
        {
            if ((sc->lmc_rxring[i].status & LMC_RDES_OWN_BIT)
                != DESC_OWNED_BY_DC21X4)
            {
                rxIntLoopCnt++;
            }
        }
        LMC_EVENT_LOG(LMC_EVENT_RCVEND, rxIntLoopCnt, 0);
    }
#endif


    lmc_led_off(sc, LMC_DS3_LED3);

skip_out_of_mem:

    lmc_trace(dev, "lmc_rx out");