Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 940 insertions, 0 deletions

diff --git a/drivers/net/3c501.c b/drivers/net/3c501.c
new file mode 100644
index 000000000000..f6d51ce34b00
--- /dev/null
+++ b/drivers/net/3c501.c
@@ -0,0 +1,940 @@
+/* 3c501.c: A 3Com 3c501 Ethernet driver for Linux. */
+/*
+    Written 1992,1993,1994  Donald Becker
+
+    Copyright 1993 United States Government as represented by the
+    Director, National Security Agency.  This software may be used and
+    distributed according to the terms of the GNU General Public License,
+    incorporated herein by reference.
+
+    This is a device driver for the 3Com Etherlink 3c501.
+    Do not purchase this card, even as a joke.  It's performance is horrible,
+    and it breaks in many ways.
+
+    The original author may be reached as becker@scyld.com, or C/O
+	Scyld Computing Corporation
+	410 Severn Ave., Suite 210
+	Annapolis MD 21403
+
+    Fixed (again!) the missing interrupt locking on TX/RX shifting.
+    		Alan Cox <Alan.Cox@linux.org>
+
+    Removed calls to init_etherdev since they are no longer needed, and
+    cleaned up modularization just a bit. The driver still allows only
+    the default address for cards when loaded as a module, but that's
+    really less braindead than anyone using a 3c501 board. :)
+		    19950208 (invid@msen.com)
+
+    Added traps for interrupts hitting the window as we clear and TX load
+    the board. Now getting 150K/second FTP with a 3c501 card. Still playing
+    with a TX-TX optimisation to see if we can touch 180-200K/second as seems
+    theoretically maximum.
+    		19950402 Alan Cox <Alan.Cox@linux.org>
+    		
+    Cleaned up for 2.3.x because we broke SMP now. 
+    		20000208 Alan Cox <alan@redhat.com>
+
+    Check up pass for 2.5. Nothing significant changed
+    		20021009 Alan Cox <alan@redhat.com>
+
+    Fixed zero fill corner case 
+    		20030104 Alan Cox <alan@redhat.com>
+    		
+    		
+   For the avoidance of doubt the "preferred form" of this code is one which
+   is in an open non patent encumbered format. Where cryptographic key signing
+   forms part of the process of creating an executable the information
+   including keys needed to generate an equivalently functional executable
+   are deemed to be part of the source code.
+
+*/
+
+
+/**
+ * DOC: 3c501 Card Notes
+ *
+ *  Some notes on this thing if you have to hack it.  [Alan]
+ *
+ *  Some documentation is available from 3Com. Due to the boards age
+ *  standard responses when you ask for this will range from 'be serious'
+ *  to 'give it to a museum'. The documentation is incomplete and mostly
+ *  of historical interest anyway. 
+ *
+ *  The basic system is a single buffer which can be used to receive or
+ *  transmit a packet. A third command mode exists when you are setting
+ *  things up.
+ *
+ *  If it's transmitting it's not receiving and vice versa. In fact the
+ *  time to get the board back into useful state after an operation is
+ *  quite large.
+ *
+ *  The driver works by keeping the board in receive mode waiting for a
+ *  packet to arrive. When one arrives it is copied out of the buffer
+ *  and delivered to the kernel. The card is reloaded and off we go.
+ *
+ *  When transmitting lp->txing is set and the card is reset (from
+ *  receive mode) [possibly losing a packet just received] to command
+ *  mode. A packet is loaded and transmit mode triggered. The interrupt
+ *  handler runs different code for transmit interrupts and can handle
+ *  returning to receive mode or retransmissions (yes you have to help
+ *  out with those too).
+ *
+ * DOC: Problems
+ *  
+ *  There are a wide variety of undocumented error returns from the card
+ *  and you basically have to kick the board and pray if they turn up. Most
+ *  only occur under extreme load or if you do something the board doesn't
+ *  like (eg touching a register at the wrong time).
+ *
+ *  The driver is less efficient than it could be. It switches through
+ *  receive mode even if more transmits are queued. If this worries you buy
+ *  a real Ethernet card.
+ *
+ *  The combination of slow receive restart and no real multicast
+ *  filter makes the board unusable with a kernel compiled for IP
+ *  multicasting in a real multicast environment. That's down to the board,
+ *  but even with no multicast programs running a multicast IP kernel is
+ *  in group 224.0.0.1 and you will therefore be listening to all multicasts.
+ *  One nv conference running over that Ethernet and you can give up.
+ *
+ */
+
+#define DRV_NAME	"3c501"
+#define DRV_VERSION	"2002/10/09"
+
+
+static const char version[] =
+	DRV_NAME ".c: " DRV_VERSION " Alan Cox (alan@redhat.com).\n";
+
+/*
+ *	Braindamage remaining:
+ *	The 3c501 board.
+ */
+
+#include <linux/module.h>
+
+#include <linux/kernel.h>
+#include <linux/fcntl.h>
+#include <linux/ioport.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/config.h>	/* for CONFIG_IP_MULTICAST */
+#include <linux/spinlock.h>
+#include <linux/ethtool.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/init.h>
+
+#include "3c501.h"
+
+/*
+ *	The boilerplate probe code.
+ */
+
+static int io=0x280;
+static int irq=5;
+static int mem_start;
+
+/**
+ * el1_probe:		-	probe for a 3c501
+ * @dev: The device structure passed in to probe. 
+ *
+ * This can be called from two places. The network layer will probe using
+ * a device structure passed in with the probe information completed. For a
+ * modular driver we use #init_module to fill in our own structure and probe
+ * for it.
+ *
+ * Returns 0 on success. ENXIO if asked not to probe and ENODEV if asked to
+ * probe and failing to find anything.
+ */
+ 
+struct net_device * __init el1_probe(int unit)
+{
+	struct net_device *dev = alloc_etherdev(sizeof(struct net_local));
+	static unsigned ports[] = { 0x280, 0x300, 0};
+	unsigned *port;
+	int err = 0;
+
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	if (unit >= 0) {
+		sprintf(dev->name, "eth%d", unit);
+		netdev_boot_setup_check(dev);
+		io = dev->base_addr;
+		irq = dev->irq;
+		mem_start = dev->mem_start & 7;
+	}
+
+	SET_MODULE_OWNER(dev);
+
+	if (io > 0x1ff) {	/* Check a single specified location. */
+		err = el1_probe1(dev, io);
+	} else if (io != 0) {
+		err = -ENXIO;		/* Don't probe at all. */
+	} else {
+		for (port = ports; *port && el1_probe1(dev, *port); port++)
+			;
+		if (!*port)
+			err = -ENODEV;
+	}
+	if (err)
+		goto out;
+	err = register_netdev(dev);
+	if (err)
+		goto out1;
+	return dev;
+out1:
+	release_region(dev->base_addr, EL1_IO_EXTENT);
+out:
+	free_netdev(dev);
+	return ERR_PTR(err);
+}
+
+/**
+ *	el1_probe1: 
+ *	@dev: The device structure to use
+ *	@ioaddr: An I/O address to probe at.
+ *
+ *	The actual probe. This is iterated over by #el1_probe in order to
+ *	check all the applicable device locations.
+ *
+ *	Returns 0 for a success, in which case the device is activated,
+ *	EAGAIN if the IRQ is in use by another driver, and ENODEV if the
+ *	board cannot be found.
+ */
+
+static int __init el1_probe1(struct net_device *dev, int ioaddr)
+{
+	struct net_local *lp;
+	const char *mname;		/* Vendor name */
+	unsigned char station_addr[6];
+	int autoirq = 0;
+	int i;
+
+	/*
+	 *	Reserve I/O resource for exclusive use by this driver
+	 */
+
+	if (!request_region(ioaddr, EL1_IO_EXTENT, DRV_NAME))
+		return -ENODEV;
+
+	/*
+	 *	Read the station address PROM data from the special port.
+	 */
+
+	for (i = 0; i < 6; i++)
+	{
+		outw(i, ioaddr + EL1_DATAPTR);
+		station_addr[i] = inb(ioaddr + EL1_SAPROM);
+	}
+	/*
+	 *	Check the first three octets of the S.A. for 3Com's prefix, or
+	 *	for the Sager NP943 prefix.
+	 */
+
+	if (station_addr[0] == 0x02  &&  station_addr[1] == 0x60
+		&& station_addr[2] == 0x8c)
+	{
+		mname = "3c501";
+	} else if (station_addr[0] == 0x00  &&  station_addr[1] == 0x80
+	&& station_addr[2] == 0xC8)
+	{
+		mname = "NP943";
+    	}
+    	else {
+		release_region(ioaddr, EL1_IO_EXTENT);
+		return -ENODEV;
+	}
+
+	/*
+	 *	We auto-IRQ by shutting off the interrupt line and letting it float
+	 *	high.
+	 */
+
+	dev->irq = irq;
+
+	if (dev->irq < 2)
+	{
+		unsigned long irq_mask;
+
+		irq_mask = probe_irq_on();
+		inb(RX_STATUS);		/* Clear pending interrupts. */
+		inb(TX_STATUS);
+		outb(AX_LOOP + 1, AX_CMD);
+
+		outb(0x00, AX_CMD);
+
+		mdelay(20);
+		autoirq = probe_irq_off(irq_mask);
+
+		if (autoirq == 0)
+		{
+			printk(KERN_WARNING "%s probe at %#x failed to detect IRQ line.\n",
+				mname, ioaddr);
+			release_region(ioaddr, EL1_IO_EXTENT);
+			return -EAGAIN;
+		}
+	}
+
+	outb(AX_RESET+AX_LOOP, AX_CMD);			/* Loopback mode. */
+	dev->base_addr = ioaddr;
+	memcpy(dev->dev_addr, station_addr, ETH_ALEN);
+
+	if (mem_start & 0xf)
+		el_debug = mem_start & 0x7;
+	if (autoirq)
+		dev->irq = autoirq;
+
+	printk(KERN_INFO "%s: %s EtherLink at %#lx, using %sIRQ %d.\n", dev->name, mname, dev->base_addr,
+			autoirq ? "auto":"assigned ", dev->irq);
+
+#ifdef CONFIG_IP_MULTICAST
+	printk(KERN_WARNING "WARNING: Use of the 3c501 in a multicast kernel is NOT recommended.\n");
+#endif
+
+	if (el_debug)
+		printk(KERN_DEBUG "%s", version);
+
+	memset(dev->priv, 0, sizeof(struct net_local));
+	lp = netdev_priv(dev);
+	spin_lock_init(&lp->lock);
+	
+	/*
+	 *	The EL1-specific entries in the device structure.
+	 */
+
+	dev->open = &el_open;
+	dev->hard_start_xmit = &el_start_xmit;
+	dev->tx_timeout = &el_timeout;
+	dev->watchdog_timeo = HZ;
+	dev->stop = &el1_close;
+	dev->get_stats = &el1_get_stats;
+	dev->set_multicast_list = &set_multicast_list;
+	dev->ethtool_ops = &netdev_ethtool_ops;
+	return 0;
+}
+
+/**
+ *	el1_open:
+ *	@dev: device that is being opened
+ *
+ *	When an ifconfig is issued which changes the device flags to include
+ *	IFF_UP this function is called. It is only called when the change 
+ *	occurs, not when the interface remains up. #el1_close will be called
+ *	when it goes down.
+ *
+ *	Returns 0 for a successful open, or -EAGAIN if someone has run off
+ *	with our interrupt line.
+ */
+
+static int el_open(struct net_device *dev)
+{
+	int retval;
+	int ioaddr = dev->base_addr;
+	struct net_local *lp = netdev_priv(dev);
+	unsigned long flags;
+
+	if (el_debug > 2)
+		printk(KERN_DEBUG "%s: Doing el_open()...", dev->name);
+
+	if ((retval = request_irq(dev->irq, &el_interrupt, 0, dev->name, dev)))
+		return retval;
+
+	spin_lock_irqsave(&lp->lock, flags);
+	el_reset(dev);
+	spin_unlock_irqrestore(&lp->lock, flags);
+
+	lp->txing = 0;		/* Board in RX mode */
+	outb(AX_RX, AX_CMD);	/* Aux control, irq and receive enabled */
+	netif_start_queue(dev);
+	return 0;
+}
+
+/**
+ * el_timeout:
+ * @dev: The 3c501 card that has timed out
+ *
+ * Attempt to restart the board. This is basically a mixture of extreme
+ * violence and prayer
+ *
+ */
+ 
+static void el_timeout(struct net_device *dev)
+{
+	struct net_local *lp = netdev_priv(dev);
+	int ioaddr = dev->base_addr;
+ 
+	if (el_debug)
+		printk (KERN_DEBUG "%s: transmit timed out, txsr %#2x axsr=%02x rxsr=%02x.\n",
+			dev->name, inb(TX_STATUS), inb(AX_STATUS), inb(RX_STATUS));
+	lp->stats.tx_errors++;
+	outb(TX_NORM, TX_CMD);
+	outb(RX_NORM, RX_CMD);
+	outb(AX_OFF, AX_CMD);	/* Just trigger a false interrupt. */
+	outb(AX_RX, AX_CMD);	/* Aux control, irq and receive enabled */
+	lp->txing = 0;		/* Ripped back in to RX */
+	netif_wake_queue(dev);
+}
+
+ 
+/**
+ * el_start_xmit:
+ * @skb: The packet that is queued to be sent
+ * @dev: The 3c501 card we want to throw it down
+ *
+ * Attempt to send a packet to a 3c501 card. There are some interesting
+ * catches here because the 3c501 is an extremely old and therefore
+ * stupid piece of technology.
+ *
+ * If we are handling an interrupt on the other CPU we cannot load a packet
+ * as we may still be attempting to retrieve the last RX packet buffer.
+ *
+ * When a transmit times out we dump the card into control mode and just
+ * start again. It happens enough that it isnt worth logging.
+ *
+ * We avoid holding the spin locks when doing the packet load to the board.
+ * The device is very slow, and its DMA mode is even slower. If we held the
+ * lock while loading 1500 bytes onto the controller we would drop a lot of
+ * serial port characters. This requires we do extra locking, but we have
+ * no real choice.
+ */
+
+static int el_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct net_local *lp = netdev_priv(dev);
+	int ioaddr = dev->base_addr;
+	unsigned long flags;
+
+	/*
+	 *	Avoid incoming interrupts between us flipping txing and flipping
+	 *	mode as the driver assumes txing is a faithful indicator of card
+	 *	state
+	 */
+
+	spin_lock_irqsave(&lp->lock, flags);
+	
+	/*
+	 *	Avoid timer-based retransmission conflicts.
+	 */
+
+	netif_stop_queue(dev);
+
+	do
+	{
+		int len = skb->len;
+		int pad = 0;
+		int gp_start;
+		unsigned char *buf = skb->data;
+		
+		if (len < ETH_ZLEN)
+			pad = ETH_ZLEN - len;
+			
+		gp_start = 0x800 - ( len + pad );
+
+		lp->tx_pkt_start = gp_start;
+    		lp->collisions = 0;
+
+    		lp->stats.tx_bytes += skb->len;
+
+		/*
+		 *	Command mode with status cleared should [in theory]
+		 *	mean no more interrupts can be pending on the card.
+		 */
+
+		outb_p(AX_SYS, AX_CMD);
+		inb_p(RX_STATUS);
+		inb_p(TX_STATUS);
+
+		lp->loading = 1;
+		lp->txing = 1;
+
+		/*
+		 *	Turn interrupts back on while we spend a pleasant afternoon
+		 *	loading bytes into the board
+		 */
+
+		spin_unlock_irqrestore(&lp->lock, flags);
+		
+		outw(0x00, RX_BUF_CLR);		/* Set rx packet area to 0. */
+		outw(gp_start, GP_LOW);		/* aim - packet will be loaded into buffer start */
+		outsb(DATAPORT,buf,len);	/* load buffer (usual thing each byte increments the pointer) */
+		if (pad) {
+			while(pad--)		/* Zero fill buffer tail */
+				outb(0, DATAPORT);
+		}
+		outw(gp_start, GP_LOW);		/* the board reuses the same register */
+	
+		if(lp->loading != 2)
+		{
+			outb(AX_XMIT, AX_CMD);		/* fire ... Trigger xmit.  */
+			lp->loading=0;
+			dev->trans_start = jiffies;
+			if (el_debug > 2)
+				printk(KERN_DEBUG " queued xmit.\n");
+			dev_kfree_skb (skb);
+			return 0;
+		}
+		/* A receive upset our load, despite our best efforts */
+		if(el_debug>2)
+			printk(KERN_DEBUG "%s: burped during tx load.\n", dev->name);
+		spin_lock_irqsave(&lp->lock, flags);
+	}
+	while(1);
+
+}
+
+/**
+ * el_interrupt:
+ * @irq: Interrupt number
+ * @dev_id: The 3c501 that burped
+ * @regs: Register data (surplus to our requirements)
+ *
+ * Handle the ether interface interrupts. The 3c501 needs a lot more 
+ * hand holding than most cards. In particular we get a transmit interrupt
+ * with a collision error because the board firmware isnt capable of rewinding
+ * its own transmit buffer pointers. It can however count to 16 for us.
+ *
+ * On the receive side the card is also very dumb. It has no buffering to
+ * speak of. We simply pull the packet out of its PIO buffer (which is slow)
+ * and queue it for the kernel. Then we reset the card for the next packet.
+ *
+ * We sometimes get suprise interrupts late both because the SMP IRQ delivery
+ * is message passing and because the card sometimes seems to deliver late. I
+ * think if it is part way through a receive and the mode is changed it carries
+ * on receiving and sends us an interrupt. We have to band aid all these cases
+ * to get a sensible 150kbytes/second performance. Even then you want a small
+ * TCP window.
+ */
+
+static irqreturn_t el_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	struct net_device *dev = dev_id;
+	struct net_local *lp;
+	int ioaddr;
+	int axsr;			/* Aux. status reg. */
+
+	ioaddr = dev->base_addr;
+	lp = netdev_priv(dev);
+
+	spin_lock(&lp->lock);
+	
+	/*
+	 *	What happened ?
+	 */
+
+	axsr = inb(AX_STATUS);
+
+	/*
+	 *	Log it
+	 */
+
+	if (el_debug > 3)
+		printk(KERN_DEBUG "%s: el_interrupt() aux=%#02x", dev->name, axsr);
+
+        if(lp->loading==1 && !lp->txing)
+        	printk(KERN_WARNING "%s: Inconsistent state loading while not in tx\n",
+        		dev->name);
+
+	if (lp->txing)
+	{
+
+    		/*
+    		 *	Board in transmit mode. May be loading. If we are
+    		 *	loading we shouldn't have got this.
+    		 */
+
+		int txsr = inb(TX_STATUS);
+
+		if(lp->loading==1)
+		{
+			if(el_debug > 2)
+			{
+				printk(KERN_DEBUG "%s: Interrupt while loading [", dev->name);
+				printk(KERN_DEBUG " txsr=%02x gp=%04x rp=%04x]\n", txsr, inw(GP_LOW),inw(RX_LOW));
+			}
+			lp->loading=2;		/* Force a reload */
+			spin_unlock(&lp->lock);
+			goto out;
+		}
+
+		if (el_debug > 6)
+			printk(KERN_DEBUG " txsr=%02x gp=%04x rp=%04x", txsr, inw(GP_LOW),inw(RX_LOW));
+
+		if ((axsr & 0x80) && (txsr & TX_READY) == 0)
+		{
+			/*
+			 *	FIXME: is there a logic to whether to keep on trying or
+			 *	reset immediately ?
+			 */
+			if(el_debug>1)
+				printk(KERN_DEBUG "%s: Unusual interrupt during Tx, txsr=%02x axsr=%02x"
+			  		" gp=%03x rp=%03x.\n", dev->name, txsr, axsr,
+			inw(ioaddr + EL1_DATAPTR), inw(ioaddr + EL1_RXPTR));
+			lp->txing = 0;
+			netif_wake_queue(dev);
+		}
+		else if (txsr & TX_16COLLISIONS)
+		{
+			/*
+			 *	Timed out
+			 */
+			if (el_debug)
+				printk (KERN_DEBUG "%s: Transmit failed 16 times, Ethernet jammed?\n",dev->name);
+			outb(AX_SYS, AX_CMD);
+			lp->txing = 0;
+			lp->stats.tx_aborted_errors++;
+			netif_wake_queue(dev);
+		}
+		else if (txsr & TX_COLLISION)
+		{
+			/*
+			 *	Retrigger xmit.
+			 */
+
+			if (el_debug > 6)
+				printk(KERN_DEBUG " retransmitting after a collision.\n");
+			/*
+			 *	Poor little chip can't reset its own start pointer
+			 */
+
+			outb(AX_SYS, AX_CMD);
+			outw(lp->tx_pkt_start, GP_LOW);
+			outb(AX_XMIT, AX_CMD);
+			lp->stats.collisions++;
+			spin_unlock(&lp->lock);
+			goto out;
+		}
+		else
+		{
+			/*
+			 *	It worked.. we will now fall through and receive
+			 */
+			lp->stats.tx_packets++;
+			if (el_debug > 6)
+				printk(KERN_DEBUG " Tx succeeded %s\n",
+		       			(txsr & TX_RDY) ? "." : "but tx is busy!");
+			/*
+			 *	This is safe the interrupt is atomic WRT itself.
+			 */
+
+			lp->txing = 0;
+			netif_wake_queue(dev);	/* In case more to transmit */
+		}
+	}
+	else
+	{
+    		/*
+    		 *	In receive mode.
+    		 */
+
+		int rxsr = inb(RX_STATUS);
+		if (el_debug > 5)
+			printk(KERN_DEBUG " rxsr=%02x txsr=%02x rp=%04x", rxsr, inb(TX_STATUS),inw(RX_LOW));
+		/*
+		 *	Just reading rx_status fixes most errors.
+		 */
+		if (rxsr & RX_MISSED)
+			lp->stats.rx_missed_errors++;
+		else if (rxsr & RX_RUNT)
+		{	/* Handled to avoid board lock-up. */
+			lp->stats.rx_length_errors++;
+			if (el_debug > 5)
+				printk(KERN_DEBUG " runt.\n");
+		}
+		else if (rxsr & RX_GOOD)
+		{
+			/*
+			 *	Receive worked.
+			 */
+			el_receive(dev);
+		}
+		else
+		{
+			/*
+			 *	Nothing?  Something is broken!
+			 */
+			if (el_debug > 2)
+				printk(KERN_DEBUG "%s: No packet seen, rxsr=%02x **resetting 3c501***\n",
+					dev->name, rxsr);
+			el_reset(dev);
+		}
+		if (el_debug > 3)
+			printk(KERN_DEBUG ".\n");
+	}
+
+	/*
+	 *	Move into receive mode
+	 */
+
+	outb(AX_RX, AX_CMD);
+	outw(0x00, RX_BUF_CLR);
+	inb(RX_STATUS);		/* Be certain that interrupts are cleared. */
+	inb(TX_STATUS);
+	spin_unlock(&lp->lock);
+out:
+	return IRQ_HANDLED;
+}
+
+
+/**
+ * el_receive:
+ * @dev: Device to pull the packets from
+ *
+ * We have a good packet. Well, not really "good", just mostly not broken.
+ * We must check everything to see if it is good. In particular we occasionally
+ * get wild packet sizes from the card. If the packet seems sane we PIO it
+ * off the card and queue it for the protocol layers.
+ */
+
+static void el_receive(struct net_device *dev)
+{
+	struct net_local *lp = netdev_priv(dev);
+	int ioaddr = dev->base_addr;
+	int pkt_len;
+	struct sk_buff *skb;
+
+	pkt_len = inw(RX_LOW);
+
+	if (el_debug > 4)
+		printk(KERN_DEBUG " el_receive %d.\n", pkt_len);
+
+	if ((pkt_len < 60)  ||  (pkt_len > 1536))
+	{
+		if (el_debug)
+			printk(KERN_DEBUG "%s: bogus packet, length=%d\n", dev->name, pkt_len);
+		lp->stats.rx_over_errors++;
+		return;
+	}
+
+	/*
+	 *	Command mode so we can empty the buffer
+	 */
+
+	outb(AX_SYS, AX_CMD);
+	skb = dev_alloc_skb(pkt_len+2);
+
+	/*
+	 *	Start of frame
+	 */
+
+	outw(0x00, GP_LOW);
+	if (skb == NULL)
+	{
+		printk(KERN_INFO "%s: Memory squeeze, dropping packet.\n", dev->name);
+		lp->stats.rx_dropped++;
+		return;
+	}
+	else
+	{
+    		skb_reserve(skb,2);	/* Force 16 byte alignment */
+		skb->dev = dev;
+		/*
+		 *	The read increments through the bytes. The interrupt
+		 *	handler will fix the pointer when it returns to
+		 *	receive mode.
+		 */
+		insb(DATAPORT, skb_put(skb,pkt_len), pkt_len);
+		skb->protocol=eth_type_trans(skb,dev);
+		netif_rx(skb);
+		dev->last_rx = jiffies;
+		lp->stats.rx_packets++;
+		lp->stats.rx_bytes+=pkt_len;
+	}
+	return;
+}
+
+/**
+ * el_reset: Reset a 3c501 card
+ * @dev: The 3c501 card about to get zapped
+ *
+ * Even resetting a 3c501 isnt simple. When you activate reset it loses all
+ * its configuration. You must hold the lock when doing this. The function
+ * cannot take the lock itself as it is callable from the irq handler.
+ */
+
+static void  el_reset(struct net_device *dev)
+{
+	struct net_local *lp = netdev_priv(dev);
+	int ioaddr = dev->base_addr;
+
+	if (el_debug> 2)
+		printk(KERN_INFO "3c501 reset...");
+	outb(AX_RESET, AX_CMD);		/* Reset the chip */
+	outb(AX_LOOP, AX_CMD);		/* Aux control, irq and loopback enabled */
+	{
+		int i;
+		for (i = 0; i < 6; i++)	/* Set the station address. */
+			outb(dev->dev_addr[i], ioaddr + i);
+	}
+
+	outw(0, RX_BUF_CLR);		/* Set rx packet area to 0. */
+	outb(TX_NORM, TX_CMD);		/* tx irq on done, collision */
+	outb(RX_NORM, RX_CMD);		/* Set Rx commands. */
+	inb(RX_STATUS);			/* Clear status. */
+	inb(TX_STATUS);
+	lp->txing = 0;
+}
+
+/**
+ * el1_close:
+ * @dev: 3c501 card to shut down
+ *
+ * Close a 3c501 card. The IFF_UP flag has been cleared by the user via
+ * the SIOCSIFFLAGS ioctl. We stop any further transmissions being queued,
+ * and then disable the interrupts. Finally we reset the chip. The effects
+ * of the rest will be cleaned up by #el1_open. Always returns 0 indicating
+ * a success.
+ */
+ 
+static int el1_close(struct net_device *dev)
+{
+	int ioaddr = dev->base_addr;
+
+	if (el_debug > 2)
+		printk(KERN_INFO "%s: Shutting down Ethernet card at %#x.\n", dev->name, ioaddr);
+
+	netif_stop_queue(dev);
+	
+	/*
+	 *	Free and disable the IRQ.
+	 */
+
+	free_irq(dev->irq, dev);
+	outb(AX_RESET, AX_CMD);		/* Reset the chip */
+
+	return 0;
+}
+
+/**
+ * el1_get_stats:
+ * @dev: The card to get the statistics for
+ *
+ * In smarter devices this function is needed to pull statistics off the
+ * board itself. The 3c501 has no hardware statistics. We maintain them all
+ * so they are by definition always up to date.
+ *
+ * Returns the statistics for the card from the card private data
+ */
+ 
+static struct net_device_stats *el1_get_stats(struct net_device *dev)
+{
+	struct net_local *lp = netdev_priv(dev);
+	return &lp->stats;
+}
+
+/**
+ * set_multicast_list:
+ * @dev: The device to adjust
+ *
+ * Set or clear the multicast filter for this adaptor to use the best-effort 
+ * filtering supported. The 3c501 supports only three modes of filtering.
+ * It always receives broadcasts and packets for itself. You can choose to
+ * optionally receive all packets, or all multicast packets on top of this.
+ */
+
+static void set_multicast_list(struct net_device *dev)
+{
+	int ioaddr = dev->base_addr;
+
+	if(dev->flags&IFF_PROMISC)
+	{
+		outb(RX_PROM, RX_CMD);
+		inb(RX_STATUS);
+	}
+	else if (dev->mc_list || dev->flags&IFF_ALLMULTI)
+	{
+		outb(RX_MULT, RX_CMD);	/* Multicast or all multicast is the same */
+		inb(RX_STATUS);		/* Clear status. */
+	}
+	else
+	{
+		outb(RX_NORM, RX_CMD);
+		inb(RX_STATUS);
+	}
+}
+
+
+static void netdev_get_drvinfo(struct net_device *dev,
+			       struct ethtool_drvinfo *info)
+{
+	strcpy(info->driver, DRV_NAME);
+	strcpy(info->version, DRV_VERSION);
+	sprintf(info->bus_info, "ISA 0x%lx", dev->base_addr);
+}
+
+static u32 netdev_get_msglevel(struct net_device *dev)
+{
+	return debug;
+}
+
+static void netdev_set_msglevel(struct net_device *dev, u32 level)
+{
+	debug = level;
+}
+
+static struct ethtool_ops netdev_ethtool_ops = {
+	.get_drvinfo		= netdev_get_drvinfo,
+	.get_msglevel		= netdev_get_msglevel,
+	.set_msglevel		= netdev_set_msglevel,
+};
+
+#ifdef MODULE
+
+static struct net_device *dev_3c501;
+
+module_param(io, int, 0);
+module_param(irq, int, 0);
+MODULE_PARM_DESC(io, "EtherLink I/O base address");
+MODULE_PARM_DESC(irq, "EtherLink IRQ number");
+
+/**
+ * init_module:
+ *
+ * When the driver is loaded as a module this function is called. We fake up
+ * a device structure with the base I/O and interrupt set as if it were being
+ * called from Space.c. This minimises the extra code that would otherwise
+ * be required.
+ *
+ * Returns 0 for success or -EIO if a card is not found. Returning an error
+ * here also causes the module to be unloaded
+ */
+ 
+int init_module(void)
+{
+	dev_3c501 = el1_probe(-1);
+	if (IS_ERR(dev_3c501))
+		return PTR_ERR(dev_3c501);
+	return 0;
+}
+
+/**
+ * cleanup_module:
+ * 
+ * The module is being unloaded. We unhook our network device from the system
+ * and then free up the resources we took when the card was found.
+ */
+ 
+void cleanup_module(void)
+{
+	struct net_device *dev = dev_3c501;
+	unregister_netdev(dev);
+	release_region(dev->base_addr, EL1_IO_EXTENT);
+	free_netdev(dev);
+}
+
+#endif /* MODULE */
+
+MODULE_AUTHOR("Donald Becker, Alan Cox");
+MODULE_DESCRIPTION("Support for the ancient 3Com 3c501 ethernet card");
+MODULE_LICENSE("GPL");
+