arcnet.c

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		lp->last_timeout = jiffies;
	}

	if (lp->cur_tx == -1)
		netif_wake_queue(dev);
}


/*
 * The typical workload of the driver: Handle the network interface
 * interrupts. Establish which device needs attention, and call the correct
 * chipset interrupt handler.
 */
irqreturn_t arcnet_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct arcnet_local *lp;
	int recbuf, status, diagstatus, didsomething, boguscount;
	int retval = IRQ_NONE;

	BUGMSG(D_DURING, "\n");

	BUGMSG(D_DURING, "in arcnet_interrupt\n");
	
	lp = dev->priv;
	BUG_ON(!lp);
		
	spin_lock(&lp->lock);

	/*
	 * RESET flag was enabled - if device is not running, we must clear it right
	 * away (but nothing else).
	 */
	if (!netif_running(dev)) {
		if (ASTATUS() & RESETflag)
			ACOMMAND(CFLAGScmd | RESETclear);
		AINTMASK(0);
		spin_unlock(&lp->lock);
		return IRQ_HANDLED;
	}

	BUGMSG(D_DURING, "in arcnet_inthandler (status=%Xh, intmask=%Xh)\n",
	       ASTATUS(), lp->intmask);

	boguscount = 5;
	do {
		status = ASTATUS();
                diagstatus = (status >> 8) & 0xFF;

		BUGMSG(D_DEBUG, "%s: %d: %s: status=%x\n",
			__FILE__,__LINE__,__FUNCTION__,status);
		didsomething = 0;

		/*
		 * RESET flag was enabled - card is resetting and if RX is
		 * disabled, it's NOT because we just got a packet.
		 * 
		 * The card is in an undefined state.  Clear it out and start over.
		 */
		if (status & RESETflag) {
			BUGMSG(D_NORMAL, "spurious reset (status=%Xh)\n", status);
			arcnet_close(dev);
			arcnet_open(dev);

			/* get out of the interrupt handler! */
			break;
		}
		/* 
		 * RX is inhibited - we must have received something. Prepare to
		 * receive into the next buffer.
		 * 
		 * We don't actually copy the received packet from the card until
		 * after the transmit handler runs (and possibly launches the next
		 * tx); this should improve latency slightly if we get both types
		 * of interrupts at once. 
		 */
		recbuf = -1;
		if (status & lp->intmask & NORXflag) {
			recbuf = lp->cur_rx;
			BUGMSG(D_DURING, "Buffer #%d: receive irq (status=%Xh)\n",
			       recbuf, status);

			lp->cur_rx = get_arcbuf(dev);
			if (lp->cur_rx != -1) {
				BUGMSG(D_DURING, "enabling receive to buffer #%d\n",
				       lp->cur_rx);
				ACOMMAND(RXcmd | (lp->cur_rx << 3) | RXbcasts);
			}
			didsomething++;
		}

		if((diagstatus & EXCNAKflag)) {
			BUGMSG(D_DURING, "EXCNAK IRQ (diagstat=%Xh)\n",
			       diagstatus);

                        ACOMMAND(NOTXcmd);      /* disable transmit */
                        lp->excnak_pending = 1;

                        ACOMMAND(EXCNAKclear);
			lp->intmask &= ~(EXCNAKflag);
                        didsomething++;
                }


		/* a transmit finished, and we're interested in it. */
		if ((status & lp->intmask & TXFREEflag) || lp->timed_out) {
			lp->intmask &= ~(TXFREEflag|EXCNAKflag);

			BUGMSG(D_DURING, "TX IRQ (stat=%Xh)\n", status);

			if (lp->cur_tx != -1 && !lp->timed_out) {
				if(!(status & TXACKflag)) {
					if (lp->lasttrans_dest != 0) {
						BUGMSG(D_EXTRA,
						       "transmit was not acknowledged! "
						       "(status=%Xh, dest=%02Xh)\n",
						       status, lp->lasttrans_dest);
						lp->stats.tx_errors++;
						lp->stats.tx_carrier_errors++;
					} else {
						BUGMSG(D_DURING,
						       "broadcast was not acknowledged; that's normal "
						       "(status=%Xh, dest=%02Xh)\n",
						       status, lp->lasttrans_dest);
					}
				}

				if (lp->outgoing.proto &&
				    lp->outgoing.proto->ack_tx) {
				  int ackstatus;
				  if(status & TXACKflag)
                                    ackstatus=2;
                                  else if(lp->excnak_pending)
                                    ackstatus=1;
                                  else
                                    ackstatus=0;

                                  lp->outgoing.proto
                                    ->ack_tx(dev, ackstatus);
				}
			}
			if (lp->cur_tx != -1)
				release_arcbuf(dev, lp->cur_tx);

			lp->cur_tx = -1;
			lp->timed_out = 0;
			didsomething++;

			/* send another packet if there is one */
			go_tx(dev);

			/* continue a split packet, if any */
			if (lp->outgoing.proto && lp->outgoing.proto->continue_tx) {
				int txbuf = get_arcbuf(dev);
				if (txbuf != -1) {
					if (lp->outgoing.proto->continue_tx(dev, txbuf)) {
						/* that was the last segment */
						lp->stats.tx_bytes += lp->outgoing.skb->len;
						if(!lp->outgoing.proto->ack_tx)
						  {
						    dev_kfree_skb_irq(lp->outgoing.skb);
						    lp->outgoing.proto = NULL;
						  }
					}
					lp->next_tx = txbuf;
				}
			}
			/* inform upper layers of idleness, if necessary */
			if (lp->cur_tx == -1)
				netif_wake_queue(dev);
		}
		/* now process the received packet, if any */
		if (recbuf != -1) {
			BUGLVL(D_RX) arcnet_dump_packet(dev, recbuf, "rx irq", 0);

			arcnet_rx(dev, recbuf);
			release_arcbuf(dev, recbuf);

			didsomething++;
		}
		if (status & lp->intmask & RECONflag) {
			ACOMMAND(CFLAGScmd | CONFIGclear);
			lp->stats.tx_carrier_errors++;

			BUGMSG(D_RECON, "Network reconfiguration detected (status=%Xh)\n",
			       status);
			/* MYRECON bit is at bit 7 of diagstatus */
			if(diagstatus & 0x80)
				BUGMSG(D_RECON,"Put out that recon myself\n");

			/* is the RECON info empty or old? */
			if (!lp->first_recon || !lp->last_recon ||
			    jiffies - lp->last_recon > HZ * 10) {
				if (lp->network_down)
					BUGMSG(D_NORMAL, "reconfiguration detected: cabling restored?\n");
				lp->first_recon = lp->last_recon = jiffies;
				lp->num_recons = lp->network_down = 0;

				BUGMSG(D_DURING, "recon: clearing counters.\n");
			} else {	/* add to current RECON counter */
				lp->last_recon = jiffies;
				lp->num_recons++;

				BUGMSG(D_DURING, "recon: counter=%d, time=%lds, net=%d\n",
				       lp->num_recons,
				 (lp->last_recon - lp->first_recon) / HZ,
				       lp->network_down);

				/* if network is marked up;
				 * and first_recon and last_recon are 60+ apart;
				 * and the average no. of recons counted is
				 *    > RECON_THRESHOLD/min;
				 * then print a warning message.
				 */
				if (!lp->network_down
				    && (lp->last_recon - lp->first_recon) <= HZ * 60
				  && lp->num_recons >= RECON_THRESHOLD) {
					lp->network_down = 1;
					BUGMSG(D_NORMAL, "many reconfigurations detected: cabling problem?\n");
				} else if (!lp->network_down
					   && lp->last_recon - lp->first_recon > HZ * 60) {
					/* reset counters if we've gone for over a minute. */
					lp->first_recon = lp->last_recon;
					lp->num_recons = 1;
				}
			}
		} else if (lp->network_down && jiffies - lp->last_recon > HZ * 10) {
			if (lp->network_down)
				BUGMSG(D_NORMAL, "cabling restored?\n");
			lp->first_recon = lp->last_recon = 0;
			lp->num_recons = lp->network_down = 0;

			BUGMSG(D_DURING, "not recon: clearing counters anyway.\n");
		}

		if(didsomething) {
			retval |= IRQ_HANDLED;
		}
	}
	while (--boguscount && didsomething);

	BUGMSG(D_DURING, "arcnet_interrupt complete (status=%Xh, count=%d)\n",
	       ASTATUS(), boguscount);
	BUGMSG(D_DURING, "\n");


	AINTMASK(0);
	udelay(1);
	AINTMASK(lp->intmask);
	
	spin_unlock(&lp->lock);
	return retval;
}


/*
 * This is a generic packet receiver that calls arcnet??_rx depending on the
 * protocol ID found.
 */
static void arcnet_rx(struct net_device *dev, int bufnum)
{
	struct arcnet_local *lp = dev->priv;
	struct archdr pkt;
	struct arc_rfc1201 *soft;
	int length, ofs;

	soft = &pkt.soft.rfc1201;

	lp->hw.copy_from_card(dev, bufnum, 0, &pkt, sizeof(ARC_HDR_SIZE));
	if (pkt.hard.offset[0]) {
		ofs = pkt.hard.offset[0];
		length = 256 - ofs;
	} else {
		ofs = pkt.hard.offset[1];
		length = 512 - ofs;
	}

	/* get the full header, if possible */
	if (sizeof(pkt.soft) <= length)
		lp->hw.copy_from_card(dev, bufnum, ofs, soft, sizeof(pkt.soft));
	else {
		memset(&pkt.soft, 0, sizeof(pkt.soft));
		lp->hw.copy_from_card(dev, bufnum, ofs, soft, length);
	}

	BUGMSG(D_DURING, "Buffer #%d: received packet from %02Xh to %02Xh "
	       "(%d+4 bytes)\n",
	       bufnum, pkt.hard.source, pkt.hard.dest, length);

	lp->stats.rx_packets++;
	lp->stats.rx_bytes += length + ARC_HDR_SIZE;

	/* call the right receiver for the protocol */
	if (arc_proto_map[soft->proto]->is_ip) {
		BUGLVL(D_PROTO) {
			struct ArcProto
			*oldp = arc_proto_map[lp->default_proto[pkt.hard.source]],
			*newp = arc_proto_map[soft->proto];

			if (oldp != newp) {
				BUGMSG(D_PROTO,
				       "got protocol %02Xh; encap for host %02Xh is now '%c'"
				       " (was '%c')\n", soft->proto, pkt.hard.source,
				       newp->suffix, oldp->suffix);
			}
		}

		/* broadcasts will always be done with the last-used encap. */
		lp->default_proto[0] = soft->proto;

		/* in striking contrast, the following isn't a hack. */
		lp->default_proto[pkt.hard.source] = soft->proto;
	}
	/* call the protocol-specific receiver. */
	arc_proto_map[soft->proto]->rx(dev, bufnum, &pkt, length);
}



/* 
 * Get the current statistics.  This may be called with the card open or
 * closed.
 */
static struct net_device_stats *arcnet_get_stats(struct net_device *dev)
{
	struct arcnet_local *lp = dev->priv;
	return &lp->stats;
}


static void null_rx(struct net_device *dev, int bufnum,
		    struct archdr *pkthdr, int length)
{
	BUGMSG(D_PROTO,
	"rx: don't know how to deal with proto %02Xh from host %02Xh.\n",
	       pkthdr->soft.rfc1201.proto, pkthdr->hard.source);
}


static int null_build_header(struct sk_buff *skb, struct net_device *dev,
			     unsigned short type, uint8_t daddr)
{
	struct arcnet_local *lp = dev->priv;

	BUGMSG(D_PROTO,
	       "tx: can't build header for encap %02Xh; load a protocol driver.\n",
	       lp->default_proto[daddr]);

	/* always fails */
	return 0;
}


/* the "do nothing" prepare_tx function warns that there's nothing to do. */
static int null_prepare_tx(struct net_device *dev, struct archdr *pkt,
			   int length, int bufnum)
{
	struct arcnet_local *lp = dev->priv;
	struct arc_hardware newpkt;

	BUGMSG(D_PROTO, "tx: no encap for this host; load a protocol driver.\n");

	/* send a packet to myself -- will never get received, of course */
	newpkt.source = newpkt.dest = dev->dev_addr[0];

	/* only one byte of actual data (and it's random) */
	newpkt.offset[0] = 0xFF;

	lp->hw.copy_to_card(dev, bufnum, 0, &newpkt, ARC_HDR_SIZE);

	return 1;		/* done */
}