3c*/acenic/typhoon: Move 3Com Ethernet drivers

Moves the 3Com drivers into drivers/net/ethernet/3com/ and the necessary
Kconfig and Makefile changes.

Did not move the following drivers becuase they use a non-3Com
chipset: 3c503, 3c505, 3c507, 3c523 and 3c527

CC: Steffen Klassert <klassert@mathematik.tu-chemnitz.de>
CC: David Dillow <dave@thedillows.org>
CC: Jes Sorensen <jes@trained-monkey.org>
CC: Alan Cox <alan@linux.intel.com>
CC: David Hinds <dahinds@users.sourceforge.net>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: David Dillow <dave@thedillows.org>

1 files changed, 896 insertions, 0 deletions

diff --git a/drivers/net/ethernet/3com/3c501.c b/drivers/net/ethernet/3com/3c501.c
new file mode 100644
index 000000000000..5420f6de27df
--- /dev/null
+++ b/drivers/net/ethernet/3com/3c501.c
@@ -0,0 +1,896 @@
+/* 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@lxorguk.ukuu.org.uk>
+
+    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@lxorguk.ukuu.org.uk>
+
+    Cleaned up for 2.3.x because we broke SMP now.
+                20000208 Alan Cox <alan@lxorguk.ukuu.org.uk>
+
+    Check up pass for 2.5. Nothing significant changed
+                20021009 Alan Cox <alan@lxorguk.ukuu.org.uk>
+
+    Fixed zero fill corner case
+                20030104 Alan Cox <alan@lxorguk.ukuu.org.uk>
+
+
+   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@lxorguk.ukuu.org.uk).\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/string.h>
+#include <linux/errno.h>
+#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 const unsigned ports[] = { 0x280, 0x300, 0};
+        const 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;
+        }
+
+        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);
+}
+
+static const struct net_device_ops el_netdev_ops = {
+        .ndo_open               = el_open,
+        .ndo_stop               = el1_close,
+        .ndo_start_xmit         = el_start_xmit,
+        .ndo_tx_timeout         = el_timeout,
+        .ndo_set_multicast_list = set_multicast_list,
+        .ndo_change_mtu         = eth_change_mtu,
+        .ndo_set_mac_address    = eth_mac_addr,
+        .ndo_validate_addr      = eth_validate_addr,
+};
+
+/**
+ *      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) {
+                        pr_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;
+
+        pr_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
+        pr_warning("WARNING: Use of the 3c501 in a multicast kernel is NOT recommended.\n");
+#endif
+
+        if (el_debug)
+                pr_debug("%s", version);
+
+        lp = netdev_priv(dev);
+        memset(lp, 0, sizeof(struct net_local));
+        spin_lock_init(&lp->lock);
+
+        /*
+         *      The EL1-specific entries in the device structure.
+         */
+
+        dev->netdev_ops = &el_netdev_ops;
+        dev->watchdog_timeo = HZ;
+        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)
+                pr_debug("%s: Doing el_open()...\n", dev->name);
+
+        retval = request_irq(dev->irq, el_interrupt, 0, dev->name, dev);
+        if (retval)
+                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)
+                pr_debug("%s: transmit timed out, txsr %#2x axsr=%02x rxsr=%02x.\n",
+                        dev->name, inb(TX_STATUS),
+                        inb(AX_STATUS), inb(RX_STATUS));
+        dev->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 isn't 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 netdev_tx_t 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;
+
+                dev->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);
+
+                /* Set rx packet area to 0. */
+                outw(0x00, RX_BUF_CLR);
+                /* aim - packet will be loaded into buffer start */
+                outw(gp_start, GP_LOW);
+                /* load buffer (usual thing each byte increments the pointer) */
+                outsb(DATAPORT, buf, len);
+                if (pad) {
+                        while (pad--)           /* Zero fill buffer tail */
+                                outb(0, DATAPORT);
+                }
+                /* the board reuses the same register */
+                outw(gp_start, GP_LOW);
+
+                if (lp->loading != 2) {
+                        /* fire ... Trigger xmit.  */
+                        outb(AX_XMIT, AX_CMD);
+                        lp->loading = 0;
+                        if (el_debug > 2)
+                                pr_debug(" queued xmit.\n");
+                        dev_kfree_skb(skb);
+                        return NETDEV_TX_OK;
+                }
+                /* A receive upset our load, despite our best efforts */
+                if (el_debug > 2)
+                        pr_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
+ *
+ * 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 isn't 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 surprise 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 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)
+                pr_debug("%s: el_interrupt() aux=%#02x\n", dev->name, axsr);
+
+        if (lp->loading == 1 && !lp->txing)
+                pr_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)
+                                pr_debug("%s: Interrupt while loading [txsr=%02x gp=%04x rp=%04x]\n",
+                                        dev->name, txsr, inw(GP_LOW), inw(RX_LOW));
+
+                        /* Force a reload */
+                        lp->loading = 2;
+                        spin_unlock(&lp->lock);
+                        goto out;
+                }
+                if (el_debug > 6)
+                        pr_debug("%s: txsr=%02x gp=%04x rp=%04x\n", dev->name,
+                                        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)
+                                pr_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)
+                                pr_debug("%s: Transmit failed 16 times, Ethernet jammed?\n", dev->name);
+                        outb(AX_SYS, AX_CMD);
+                        lp->txing = 0;
+                        dev->stats.tx_aborted_errors++;
+                        netif_wake_queue(dev);
+                } else if (txsr & TX_COLLISION) {
+                        /*
+                         *      Retrigger xmit.
+                         */
+
+                        if (el_debug > 6)
+                                pr_debug("%s: retransmitting after a collision.\n", dev->name);
+                        /*
+                         *      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);
+                        dev->stats.collisions++;
+                        spin_unlock(&lp->lock);
+                        goto out;
+                } else {
+                        /*
+                         *      It worked.. we will now fall through and receive
+                         */
+                        dev->stats.tx_packets++;
+                        if (el_debug > 6)
+                                pr_debug("%s: Tx succeeded %s\n", dev->name,
+                                        (txsr & TX_RDY) ? "." : "but tx is busy!");
+                        /*
+                         *      This is safe the interrupt is atomic WRT itself.
+                         */
+                        lp->txing = 0;
+                        /* In case more to transmit */
+                        netif_wake_queue(dev);
+                }
+        } else {
+                /*
+                 *      In receive mode.
+                 */
+
+                int rxsr = inb(RX_STATUS);
+                if (el_debug > 5)
+                        pr_debug("%s: rxsr=%02x txsr=%02x rp=%04x\n",
+                                dev->name, rxsr, inb(TX_STATUS), inw(RX_LOW));
+                /*
+                 *      Just reading rx_status fixes most errors.
+                 */
+                if (rxsr & RX_MISSED)
+                        dev->stats.rx_missed_errors++;
+                else if (rxsr & RX_RUNT) {
+                        /* Handled to avoid board lock-up. */
+                        dev->stats.rx_length_errors++;
+                        if (el_debug > 5)
+                                pr_debug("%s: runt.\n", dev->name);
+                } else if (rxsr & RX_GOOD) {
+                        /*
+                         *      Receive worked.
+                         */
+                        el_receive(dev);
+                } else {
+                        /*
+                         *      Nothing?  Something is broken!
+                         */
+                        if (el_debug > 2)
+                                pr_debug("%s: No packet seen, rxsr=%02x **resetting 3c501***\n",
+                                        dev->name, rxsr);
+                        el_reset(dev);
+                }
+        }
+
+        /*
+         *      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)
+{
+        int ioaddr = dev->base_addr;
+        int pkt_len;
+        struct sk_buff *skb;
+
+        pkt_len = inw(RX_LOW);
+
+        if (el_debug > 4)
+                pr_debug(" el_receive %d.\n", pkt_len);
+
+        if (pkt_len < 60 || pkt_len > 1536) {
+                if (el_debug)
+                        pr_debug("%s: bogus packet, length=%d\n",
+                                                dev->name, pkt_len);
+                dev->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) {
+                pr_info("%s: Memory squeeze, dropping packet.\n", dev->name);
+                dev->stats.rx_dropped++;
+                return;
+        } else {
+                skb_reserve(skb, 2);    /* Force 16 byte alignment */
+                /*
+                 *      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->stats.rx_packets++;
+                dev->stats.rx_bytes += pkt_len;
+        }
+}
+
+/**
+ * el_reset: Reset a 3c501 card
+ * @dev: The 3c501 card about to get zapped
+ *
+ * Even resetting a 3c501 isn't 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)
+                pr_info("3c501 reset...\n");
+        outb(AX_RESET, AX_CMD);         /* Reset the chip */
+        /* Aux control, irq and loopback enabled */
+        outb(AX_LOOP, AX_CMD);
+        {
+                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)
+                pr_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;
+}
+
+/**
+ * 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 (!netdev_mc_empty(dev) || dev->flags & IFF_ALLMULTI) {
+                /* Multicast or all multicast is the same */
+                outb(RX_MULT, RX_CMD);
+                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 const 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 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 __exit 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");
+