3c505.c

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/*
 * Linux Ethernet device driver for the 3Com Etherlink Plus (3C505)
 *      By Craig Southeren, Juha Laiho and Philip Blundell
 *
 * 3c505.c      This module implements an interface to the 3Com
 *              Etherlink Plus (3c505) Ethernet card. Linux device
 *              driver interface reverse engineered from the Linux 3C509
 *              device drivers. Some 3C505 information gleaned from
 *              the Crynwr packet driver. Still this driver would not
 *              be here without 3C505 technical reference provided by
 *              3Com.
 *
 * $Id: 3c505.c,v 1.10 1996/04/16 13:06:27 phil Exp $
 *
 * Authors:     Linux 3c505 device driver by
 *                      Craig Southeren, <[email protected]>
 *              Final debugging by
 *                      Andrew Tridgell, <[email protected]>
 *              Auto irq/address, tuning, cleanup and v1.1.4+ kernel mods by
 *                      Juha Laiho, <[email protected]>
 *              Linux 3C509 driver by
 *                      Donald Becker, <[email protected]>
 *          (Now at <[email protected]>)
 *              Crynwr packet driver by
 *                      Krishnan Gopalan and Gregg Stefancik,
 *                      Clemson University Engineering Computer Operations.
 *                      Portions of the code have been adapted from the 3c505
 *                         driver for NCSA Telnet by Bruce Orchard and later
 *                         modified by Warren Van Houten and [email protected].
 *              3C505 technical information provided by
 *                      Terry Murphy, of 3Com Network Adapter Division
 *              Linux 1.3.0 changes by
 *                      Alan Cox <[email protected]>
 *              More debugging, DMA support, currently maintained by
 *                      Philip Blundell <[email protected]>
 *              Multicard/soft configurable dma channel/rev 2 hardware support
 *                      by Christopher Collins <[email protected]>
 *      Ethtool support (jgarzik), 11/17/2001
 */

#define DRV_NAME    "3c505"
#define DRV_VERSION "1.10a"


/* Theory of operation:
 *
 * The 3c505 is quite an intelligent board.  All communication with it is done
 * by means of Primary Command Blocks (PCBs); these are transferred using PIO
 * through the command register.  The card has 256k of on-board RAM, which is
 * used to buffer received packets.  It might seem at first that more buffers
 * are better, but in fact this isn't true.  From my tests, it seems that
 * more than about 10 buffers are unnecessary, and there is a noticeable
 * performance hit in having more active on the card.  So the majority of the
 * card's memory isn't, in fact, used.  Sadly, the card only has one transmit
 * buffer and, short of loading our own firmware into it (which is what some
 * drivers resort to) there's nothing we can do about this.
 *
 * We keep up to 4 "receive packet" commands active on the board at a time.
 * When a packet comes in, so long as there is a receive command active, the
 * board will send us a "packet received" PCB and then add the data for that
 * packet to the DMA queue.  If a DMA transfer is not already in progress, we
 * set one up to start uploading the data.  We have to maintain a list of
 * backlogged receive packets, because the card may decide to tell us about
 * a newly-arrived packet at any time, and we may not be able to start a DMA
 * transfer immediately (ie one may already be going on).  We can't NAK the
 * PCB, because then it would throw the packet away.
 *
 * Trying to send a PCB to the card at the wrong moment seems to have bad
 * effects.  If we send it a transmit PCB while a receive DMA is happening,
 * it will just NAK the PCB and so we will have wasted our time.  Worse, it
 * sometimes seems to interrupt the transfer.  The majority of the low-level
 * code is protected by one huge semaphore -- "busy" -- which is set whenever
 * it probably isn't safe to do anything to the card.  The receive routine
 * must gain a lock on "busy" before it can start a DMA transfer, and the
 * transmit routine must gain a lock before it sends the first PCB to the card.
 * The send_pcb() routine also has an internal semaphore to protect it against
 * being re-entered (which would be disastrous) -- this is needed because
 * several things can happen asynchronously (re-priming the receiver and
 * asking the card for statistics, for example).  send_pcb() will also refuse
 * to talk to the card at all if a DMA upload is happening.  The higher-level
 * networking code will reschedule a later retry if some part of the driver
 * is blocked.  In practice, this doesn't seem to happen very often.
 */

/* This driver may now work with revision 2.x hardware, since all the read
 * operations on the HCR have been removed (we now keep our own softcopy).
 * But I don't have an old card to test it on.
 *
 * This has had the bad effect that the autoprobe routine is now a bit
 * less friendly to other devices.  However, it was never very good.
 * before, so I doubt it will hurt anybody.
 */

/* The driver is a mess.  I took Craig's and Juha's code, and hacked it firstly
 * to make it more reliable, and secondly to add DMA mode.  Many things could
 * probably be done better; the concurrency protection is particularly awful.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/ioport.h>
#include <linux/spinlock.h>
#include <linux/ethtool.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/gfp.h>

#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/dma.h>

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>

#include "3c505.h"

/*********************************************************
 *
 *  define debug messages here as common strings to reduce space
 *
 *********************************************************/

#define timeout_msg "*** timeout at %s:%s (line %d) ***\n"
#define TIMEOUT_MSG(lineno) \
    pr_notice(timeout_msg, __FILE__, __func__, (lineno))

#define invalid_pcb_msg "*** invalid pcb length %d at %s:%s (line %d) ***\n"
#define INVALID_PCB_MSG(len) \
    pr_notice(invalid_pcb_msg, (len), __FILE__, __func__, __LINE__)

#define search_msg "%s: Looking for 3c505 adapter at address %#x..."

#define stilllooking_msg "still looking..."

#define found_msg "found.\n"

#define notfound_msg "not found (reason = %d)\n"

#define couldnot_msg "%s: 3c505 not found\n"

/*********************************************************
 *
 *  various other debug stuff
 *
 *********************************************************/

#ifdef ELP_DEBUG
static int elp_debug = ELP_DEBUG;
#else
static int elp_debug;
#endif
#define debug elp_debug

/*
 *  0 = no messages (well, some)
 *  1 = messages when high level commands performed
 *  2 = messages when low level commands performed
 *  3 = messages when interrupts received
 */

/*****************************************************************
 *
 * List of I/O-addresses we try to auto-sense
 * Last element MUST BE 0!
 *****************************************************************/

static int addr_list[] __initdata = {0x300, 0x280, 0x310, 0};

/* Dma Memory related stuff */

static unsigned long dma_mem_alloc(int size)
{
    int order = get_order(size);
    return __get_dma_pages(GFP_KERNEL, order);
}


/*****************************************************************
 *
 * Functions for I/O (note the inline !)
 *
 *****************************************************************/

static inline unsigned char inb_status(unsigned int base_addr)
{
    return inb(base_addr + PORT_STATUS);
}

static inline int inb_command(unsigned int base_addr)
{
    return inb(base_addr + PORT_COMMAND);
}

static inline void outb_control(unsigned char val, struct net_device *dev)
{
    outb(val, dev->base_addr + PORT_CONTROL);
    ((elp_device *)(netdev_priv(dev)))->hcr_val = val;
}

#define HCR_VAL(x)   (((elp_device *)(netdev_priv(x)))->hcr_val)

static inline void outb_command(unsigned char val, unsigned int base_addr)
{
    outb(val, base_addr + PORT_COMMAND);
}

static inline unsigned int backlog_next(unsigned int n)
{
    return (n + 1) % BACKLOG_SIZE;
}

/*****************************************************************
 *
 *  useful functions for accessing the adapter
 *
 *****************************************************************/

/*
 * use this routine when accessing the ASF bits as they are
 * changed asynchronously by the adapter
 */

/* get adapter PCB status */
#define GET_ASF(addr) \
    (get_status(addr)&ASF_PCB_MASK)

static inline int get_status(unsigned int base_addr)
{
    unsigned long timeout = jiffies + 10*HZ/100;
    register int stat1;
    do {
        stat1 = inb_status(base_addr);
    } while (stat1 != inb_status(base_addr) && time_before(jiffies, timeout));
    if (time_after_eq(jiffies, timeout))
        TIMEOUT_MSG(__LINE__);
    return stat1;
}

static inline void set_hsf(struct net_device *dev, int hsf)
{
    elp_device *adapter = netdev_priv(dev);
    unsigned long flags;

    spin_lock_irqsave(&adapter->lock, flags);
    outb_control((HCR_VAL(dev) & ~HSF_PCB_MASK) | hsf, dev);
    spin_unlock_irqrestore(&adapter->lock, flags);
}

static bool start_receive(struct net_device *, pcb_struct *);

static inline void adapter_reset(struct net_device *dev)
{
    unsigned long timeout;
    elp_device *adapter = netdev_priv(dev);
    unsigned char orig_hcr = adapter->hcr_val;

    outb_control(0, dev);

    if (inb_status(dev->base_addr) & ACRF) {
        do {
            inb_command(dev->base_addr);
            timeout = jiffies + 2*HZ/100;
            while (time_before_eq(jiffies, timeout) && !(inb_status(dev->base_addr) & ACRF));
        } while (inb_status(dev->base_addr) & ACRF);
        set_hsf(dev, HSF_PCB_NAK);
    }
    outb_control(adapter->hcr_val | ATTN | DIR, dev);
    mdelay(10);
    outb_control(adapter->hcr_val & ~ATTN, dev);
    mdelay(10);
    outb_control(adapter->hcr_val | FLSH, dev);
    mdelay(10);
    outb_control(adapter->hcr_val & ~FLSH, dev);
    mdelay(10);

    outb_control(orig_hcr, dev);
    if (!start_receive(dev, &adapter->tx_pcb))
        pr_err("%s: start receive command failed\n", dev->name);
}

/* Check to make sure that a DMA transfer hasn't timed out.  This should
 * never happen in theory, but seems to occur occasionally if the card gets
 * prodded at the wrong time.
 */
static inline void check_3c505_dma(struct net_device *dev)
{
    elp_device *adapter = netdev_priv(dev);
    if (adapter->dmaing && time_after(jiffies, adapter->current_dma.start_time + 10)) {
        unsigned long flags, f;
        pr_err("%s: DMA %s timed out, %d bytes left\n", dev->name,
            adapter->current_dma.direction ? "download" : "upload",
            get_dma_residue(dev->dma));
        spin_lock_irqsave(&adapter->lock, flags);
        adapter->dmaing = 0;
        adapter->busy = 0;

        f=claim_dma_lock();
        disable_dma(dev->dma);
        release_dma_lock(f);

        if (adapter->rx_active)
            adapter->rx_active--;
        outb_control(adapter->hcr_val & ~(DMAE | TCEN | DIR), dev);
        spin_unlock_irqrestore(&adapter->lock, flags);
    }
}

/* Primitive functions used by send_pcb() */
static inline bool send_pcb_slow(unsigned int base_addr, unsigned char byte)
{
    unsigned long timeout;
    outb_command(byte, base_addr);
    for (timeout = jiffies + 5*HZ/100; time_before(jiffies, timeout);) {
        if (inb_status(base_addr) & HCRE)
            return false;
    }
    pr_warning("3c505: send_pcb_slow timed out\n");
    return true;
}

static inline bool send_pcb_fast(unsigned int base_addr, unsigned char byte)
{
    unsigned int timeout;
    outb_command(byte, base_addr);
    for (timeout = 0; timeout < 40000; timeout++) {
        if (inb_status(base_addr) & HCRE)
            return false;
    }
    pr_warning("3c505: send_pcb_fast timed out\n");
    return true;
}

/* Check to see if the receiver needs restarting, and kick it if so */
static inline void prime_rx(struct net_device *dev)
{
    elp_device *adapter = netdev_priv(dev);
    while (adapter->rx_active < ELP_RX_PCBS && netif_running(dev)) {
        if (!start_receive(dev, &adapter->itx_pcb))
            break;
    }
}

/*****************************************************************
 *
 * send_pcb
 *   Send a PCB to the adapter.
 *
 *  output byte to command reg  --<--+
 *  wait until HCRE is non zero      |
 *  loop until all bytes sent   -->--+
 *  set HSF1 and HSF2 to 1
 *  output pcb length
 *  wait until ASF give ACK or NAK
 *  set HSF1 and HSF2 to 0
 *
 *****************************************************************/

/* This can be quite slow -- the adapter is allowed to take up to 40ms
 * to respond to the initial interrupt.
 *
 * We run initially with interrupts turned on, but with a semaphore set
 * so that nobody tries to re-enter this code.  Once the first byte has
 * gone through, we turn interrupts off and then send the others (the
 * timeout is reduced to 500us).
 */

static bool send_pcb(struct net_device *dev, pcb_struct * pcb)
{
    int i;
    unsigned long timeout;
    elp_device *adapter = netdev_priv(dev);
    unsigned long flags;

    check_3c505_dma(dev);

    if (adapter->dmaing && adapter->current_dma.direction == 0)
        return false;

    /* Avoid contention */
    if (test_and_set_bit(1, &adapter->send_pcb_semaphore)) {
        if (elp_debug >= 3) {
            pr_debug("%s: send_pcb entered while threaded\n", dev->name);
        }
        return false;
    }
    /*
     * load each byte into the command register and
     * wait for the HCRE bit to indicate the adapter
     * had read the byte
     */
    set_hsf(dev, 0);

    if (send_pcb_slow(dev->base_addr, pcb->command))
        goto abort;

    spin_lock_irqsave(&adapter->lock, flags);

    if (send_pcb_fast(dev->base_addr, pcb->length))
        goto sti_abort;

    for (i = 0; i < pcb->length; i++) {
        if (send_pcb_fast(dev->base_addr, pcb->data.raw[i]))
            goto sti_abort;
    }

    outb_control(adapter->hcr_val | 3, dev);    /* signal end of PCB */
    outb_command(2 + pcb->length, dev->base_addr);

    /* now wait for the acknowledgement */
    spin_unlock_irqrestore(&adapter->lock, flags);

    for (timeout = jiffies + 5*HZ/100; time_before(jiffies, timeout);) {
        switch (GET_ASF(dev->base_addr)) {
        case ASF_PCB_ACK:
            adapter->send_pcb_semaphore = 0;
            return true;

        case ASF_PCB_NAK:
#ifdef ELP_DEBUG
            pr_debug("%s: send_pcb got NAK\n", dev->name);
#endif
            goto abort;
        }
    }

    if (elp_debug >= 1)
        pr_debug("%s: timeout waiting for PCB acknowledge (status %02x)\n",
            dev->name, inb_status(dev->base_addr));
    goto abort;

      sti_abort:
    spin_unlock_irqrestore(&adapter->lock, flags);
      abort:
    adapter->send_pcb_semaphore = 0;
    return false;
}


/*****************************************************************
 *
 * receive_pcb
 *   Read a PCB from the adapter
 *
 *  wait for ACRF to be non-zero        ---<---+
 *  input a byte                               |
 *  if ASF1 and ASF2 were not both one         |
 *      before byte was read, loop      --->---+
 *  set HSF1 and HSF2 for ack
 *
 *****************************************************************/

static bool receive_pcb(struct net_device *dev, pcb_struct * pcb)
{
    int i, j;
    int total_length;
    int stat;
    unsigned long timeout;
    unsigned long flags;

    elp_device *adapter = netdev_priv(dev);

    set_hsf(dev, 0);

    /* get the command code */
    timeout = jiffies + 2*HZ/100;
    while (((stat = get_status(dev->base_addr)) & ACRF) == 0 && time_before(jiffies, timeout));
    if (time_after_eq(jiffies, timeout)) {
        TIMEOUT_MSG(__LINE__);
        return false;
    }
    pcb->command = inb_command(dev->base_addr);

    /* read the data length */
    timeout = jiffies + 3*HZ/100;
    while (((stat = get_status(dev->base_addr)) & ACRF) == 0 && time_before(jiffies, timeout));
    if (time_after_eq(jiffies, timeout)) {
        TIMEOUT_MSG(__LINE__);
        pr_info("%s: status %02x\n", dev->name, stat);
        return false;
    }
    pcb->length = inb_command(dev->base_addr);

    if (pcb->length > MAX_PCB_DATA) {
        INVALID_PCB_MSG(pcb->length);
        adapter_reset(dev);
        return false;
    }
    /* read the data */
    spin_lock_irqsave(&adapter->lock, flags);
    for (i = 0; i < MAX_PCB_DATA; i++) {
        for (j = 0; j < 20000; j++) {
            stat = get_status(dev->base_addr);
            if (stat & ACRF)
                break;
        }
        pcb->data.raw[i] = inb_command(dev->base_addr);
        if ((stat & ASF_PCB_MASK) == ASF_PCB_END || j >= 20000)
            break;
    }
    spin_unlock_irqrestore(&adapter->lock, flags);
    if (i >= MAX_PCB_DATA) {
        INVALID_PCB_MSG(i);
        return false;
    }
    if (j >= 20000) {
        TIMEOUT_MSG(__LINE__);
        return false;
    }
    /* the last "data" byte was really the length! */
    total_length = pcb->data.raw[i];

    /* safety check total length vs data length */
    if (total_length != (pcb->length + 2)) {
        if (elp_debug >= 2)
            pr_warning("%s: mangled PCB received\n", dev->name);
        set_hsf(dev, HSF_PCB_NAK);
        return false;
    }

    if (pcb->command == CMD_RECEIVE_PACKET_COMPLETE) {
        if (test_and_set_bit(0, (void *) &adapter->busy)) {
            if (backlog_next(adapter->rx_backlog.in) == adapter->rx_backlog.out) {
                set_hsf(dev, HSF_PCB_NAK);
                pr_warning("%s: PCB rejected, transfer in progress and backlog full\n", dev->name);
                pcb->command = 0;
                return true;
            } else {
                pcb->command = 0xff;
            }
        }
    }
    set_hsf(dev, HSF_PCB_ACK);
    return true;
}

/******************************************************
 *
 *  queue a receive command on the adapter so we will get an
 *  interrupt when a packet is received.
 *
 ******************************************************/

static bool start_receive(struct net_device *dev, pcb_struct * tx_pcb)
{
    bool status;
    elp_device *adapter = netdev_priv(dev);

    if (elp_debug >= 3)
        pr_debug("%s: restarting receiver\n", dev->name);
    tx_pcb->command = CMD_RECEIVE_PACKET;
    tx_pcb->length = sizeof(struct Rcv_pkt);
    tx_pcb->data.rcv_pkt.buf_seg
        = tx_pcb->data.rcv_pkt.buf_ofs = 0;     /* Unused */
    tx_pcb->data.rcv_pkt.buf_len = 1600;
    tx_pcb->data.rcv_pkt.timeout = 0;   /* set timeout to zero */
    status = send_pcb(dev, tx_pcb);
    if (status)
        adapter->rx_active++;
    return status;
}

/******************************************************
 *
 * extract a packet from the adapter
 * this routine is only called from within the interrupt
 * service routine, so no cli/sti calls are needed
 * note that the length is always assumed to be even
 *
 ******************************************************/

static void receive_packet(struct net_device *dev, int len)
{
    int rlen;
    elp_device *adapter = netdev_priv(dev);
    void *target;
    struct sk_buff *skb;
    unsigned long flags;

    rlen = (len + 1) & ~1;
    skb = netdev_alloc_skb(dev, rlen + 2);

    if (!skb) {
        pr_warning("%s: memory squeeze, dropping packet\n", dev->name);
        target = adapter->dma_buffer;
        adapter->current_dma.target = NULL;
        /* FIXME: stats */
        return;
    }

    skb_reserve(skb, 2);
    target = skb_put(skb, rlen);
    if ((unsigned long)(target + rlen) >= MAX_DMA_ADDRESS) {
        adapter->current_dma.target = target;
        target = adapter->dma_buffer;
    } else {
        adapter->current_dma.target = NULL;
    }

    /* if this happens, we die */
    if (test_and_set_bit(0, (void *) &adapter->dmaing))
        pr_err("%s: rx blocked, DMA in progress, dir %d\n",
            dev->name, adapter->current_dma.direction);

    adapter->current_dma.direction = 0;
    adapter->current_dma.length = rlen;
    adapter->current_dma.skb = skb;
    adapter->current_dma.start_time = jiffies;

    outb_control(adapter->hcr_val | DIR | TCEN | DMAE, dev);

    flags=claim_dma_lock();
    disable_dma(dev->dma);
    clear_dma_ff(dev->dma);
    set_dma_mode(dev->dma, 0x04);   /* dma read */
    set_dma_addr(dev->dma, isa_virt_to_bus(target));
    set_dma_count(dev->dma, rlen);
    enable_dma(dev->dma);
    release_dma_lock(flags);

    if (elp_debug >= 3) {
        pr_debug("%s: rx DMA transfer started\n", dev->name);
    }

    if (adapter->rx_active)
        adapter->rx_active--;

    if (!adapter->busy)
        pr_warning("%s: receive_packet called, busy not set.\n", dev->name);
}

/******************************************************
 *
 * interrupt handler
 *
 ******************************************************/

static irqreturn_t elp_interrupt(int irq, void *dev_id)
{
    int len;
    int dlen;
    int icount = 0;
    struct net_device *dev = dev_id;
    elp_device *adapter = netdev_priv(dev);
    unsigned long timeout;

    spin_lock(&adapter->lock);

    do {
        /*
         * has a DMA transfer finished?
         */
        if (inb_status(dev->base_addr) & DONE) {
            if (!adapter->dmaing)
                pr_warning("%s: phantom DMA completed\n", dev->name);

            if (elp_debug >= 3)
                pr_debug("%s: %s DMA complete, status %02x\n", dev->name,
                    adapter->current_dma.direction ? "tx" : "rx",
                    inb_status(dev->base_addr));

            outb_control(adapter->hcr_val & ~(DMAE | TCEN | DIR), dev);
            if (adapter->current_dma.direction) {
                dev_kfree_skb_irq(adapter->current_dma.skb);
            } else {
                struct sk_buff *skb = adapter->current_dma.skb;
                if (skb) {
                    if (adapter->current_dma.target) {
                    /* have already done the skb_put() */
                    memcpy(adapter->current_dma.target, adapter->dma_buffer, adapter->current_dma.length);
                    }
                    skb->protocol = eth_type_trans(skb,dev);
                    dev->stats.rx_bytes += skb->len;
                    netif_rx(skb);
                }
            }
            adapter->dmaing = 0;
            if (adapter->rx_backlog.in != adapter->rx_backlog.out) {
                int t = adapter->rx_backlog.length[adapter->rx_backlog.out];
                adapter->rx_backlog.out = backlog_next(adapter->rx_backlog.out);
                if (elp_debug >= 2)
                    pr_debug("%s: receiving backlogged packet (%d)\n", dev->name, t);
                receive_packet(dev, t);
            } else {
                adapter->busy = 0;
            }
        } else {
            /* has one timed out? */
            check_3c505_dma(dev);
        }

        /*
         * receive a PCB from the adapter
         */
        timeout = jiffies + 3*HZ/100;
        while ((inb_status(dev->base_addr) & ACRF) != 0 && time_before(jiffies, timeout)) {
            if (receive_pcb(dev, &adapter->irx_pcb)) {
                switch (adapter->irx_pcb.command)
                {
                case 0:
                    break;
                    /*
                     * received a packet - this must be handled fast
                     */
                case 0xff:
                case CMD_RECEIVE_PACKET_COMPLETE:
                    /* if the device isn't open, don't pass packets up the stack */
                    if (!netif_running(dev))
                        break;
                    len = adapter->irx_pcb.data.rcv_resp.pkt_len;
                    dlen = adapter->irx_pcb.data.rcv_resp.buf_len;
                    if (adapter->irx_pcb.data.rcv_resp.timeout != 0) {
                        pr_err("%s: interrupt - packet not received correctly\n", dev->name);
                    } else {
                        if (elp_debug >= 3) {
                            pr_debug("%s: interrupt - packet received of length %i (%i)\n",
                                dev->name, len, dlen);
                        }
                        if (adapter->irx_pcb.command == 0xff) {
                            if (elp_debug >= 2)
                                pr_debug("%s: adding packet to backlog (len = %d)\n",
                                    dev->name, dlen);
                            adapter->rx_backlog.length[adapter->rx_backlog.in] = dlen;
                            adapter->rx_backlog.in = backlog_next(adapter->rx_backlog.in);
                        } else {
                            receive_packet(dev, dlen);
                        }
                        if (elp_debug >= 3)
                            pr_debug("%s: packet received\n", dev->name);
                    }
                    break;

                    /*
                     * 82586 configured correctly
                     */
                case CMD_CONFIGURE_82586_RESPONSE:
                    adapter->got[CMD_CONFIGURE_82586] = 1;
                    if (elp_debug >= 3)
                        pr_debug("%s: interrupt - configure response received\n", dev->name);
                    break;

                    /*
                     * Adapter memory configuration
                     */
                case CMD_CONFIGURE_ADAPTER_RESPONSE:
                    adapter->got[CMD_CONFIGURE_ADAPTER_MEMORY] = 1;
                    if (elp_debug >= 3)
                        pr_debug("%s: Adapter memory configuration %s.\n", dev->name,
                               adapter->irx_pcb.data.failed ? "failed" : "succeeded");
                    break;

                    /*
                     * Multicast list loading
                     */
                case CMD_LOAD_MULTICAST_RESPONSE:
                    adapter->got[CMD_LOAD_MULTICAST_LIST] = 1;
                    if (elp_debug >= 3)
                        pr_debug("%s: Multicast address list loading %s.\n", dev->name,
                               adapter->irx_pcb.data.failed ? "failed" : "succeeded");
                    break;

                    /*
                     * Station address setting
                     */
                case CMD_SET_ADDRESS_RESPONSE:
                    adapter->got[CMD_SET_STATION_ADDRESS] = 1;
                    if (elp_debug >= 3)
                        pr_debug("%s: Ethernet address setting %s.\n", dev->name,
                               adapter->irx_pcb.data.failed ? "failed" : "succeeded");
                    break;


                    /*
                     * received board statistics
                     */
                case CMD_NETWORK_STATISTICS_RESPONSE:
                    dev->stats.rx_packets += adapter->irx_pcb.data.netstat.tot_recv;
                    dev->stats.tx_packets += adapter->irx_pcb.data.netstat.tot_xmit;
                    dev->stats.rx_crc_errors += adapter->irx_pcb.data.netstat.err_CRC;
                    dev->stats.rx_frame_errors += adapter->irx_pcb.data.netstat.err_align;
                    dev->stats.rx_fifo_errors += adapter->irx_pcb.data.netstat.err_ovrrun;
                    dev->stats.rx_over_errors += adapter->irx_pcb.data.netstat.err_res;
                    adapter->got[CMD_NETWORK_STATISTICS] = 1;
                    if (elp_debug >= 3)
                        pr_debug("%s: interrupt - statistics response received\n", dev->name);
                    break;

                    /*
                     * sent a packet
                     */
                case CMD_TRANSMIT_PACKET_COMPLETE:
                    if (elp_debug >= 3)
                        pr_debug("%s: interrupt - packet sent\n", dev->name);
                    if (!netif_running(dev))
                        break;
                    switch (adapter->irx_pcb.data.xmit_resp.c_stat) {
                    case 0xffff:
                        dev->stats.tx_aborted_errors++;
                        pr_info("%s: transmit timed out, network cable problem?\n", dev->name);
                        break;
                    case 0xfffe:
                        dev->stats.tx_fifo_errors++;
                        pr_info("%s: transmit timed out, FIFO underrun\n", dev->name);
                        break;
                    }
                    netif_wake_queue(dev);
                    break;

                    /*
                     * some unknown PCB
                     */
                default:
                    pr_debug("%s: unknown PCB received - %2.2x\n",
                        dev->name, adapter->irx_pcb.command);
                    break;
                }
            } else {
                pr_warning("%s: failed to read PCB on interrupt\n", dev->name);
                adapter_reset(dev);
            }
        }

    } while (icount++ < 5 && (inb_status(dev->base_addr) & (ACRF | DONE)));

    prime_rx(dev);

    /*
     * indicate no longer in interrupt routine
     */
    spin_unlock(&adapter->lock);
    return IRQ_HANDLED;
}


/******************************************************
 *
 * open the board
 *
 ******************************************************/

static int elp_open(struct net_device *dev)
{
    elp_device *adapter = netdev_priv(dev);
    int retval;

    if (elp_debug >= 3)
        pr_debug("%s: request to open device\n", dev->name);

    /*
     * make sure we actually found the device
     */
    if (adapter == NULL) {
        pr_err("%s: Opening a non-existent physical device\n", dev->name);
        return -EAGAIN;
    }
    /*
     * disable interrupts on the board
     */
    outb_control(0, dev);

    /*
     * clear any pending interrupts
     */
    inb_command(dev->base_addr);
    adapter_reset(dev);

    /*
     * no receive PCBs active
     */
    adapter->rx_active = 0;

    adapter->busy = 0;
    adapter->send_pcb_semaphore = 0;
    adapter->rx_backlog.in = 0;
    adapter->rx_backlog.out = 0;

    spin_lock_init(&adapter->lock);

    /*
     * install our interrupt service routine
     */
    if ((retval = request_irq(dev->irq, elp_interrupt, 0, dev->name, dev))) {
        pr_err("%s: could not allocate IRQ%d\n", dev->name, dev->irq);
        return retval;
    }
    if ((retval = request_dma(dev->dma, dev->name))) {
        free_irq(dev->irq, dev);
        pr_err("%s: could not allocate DMA%d channel\n", dev->name, dev->dma);
        return retval;
    }
    adapter->dma_buffer = (void *) dma_mem_alloc(DMA_BUFFER_SIZE);
    if (!adapter->dma_buffer) {
        pr_err("%s: could not allocate DMA buffer\n", dev->name);
        free_dma(dev->dma);
        free_irq(dev->irq, dev);
        return -ENOMEM;
    }
    adapter->dmaing = 0;

    /*
     * enable interrupts on the board
     */
    outb_control(CMDE, dev);

    /*
     * configure adapter memory: we need 10 multicast addresses, default==0
     */
    if (elp_debug >= 3)
        pr_debug("%s: sending 3c505 memory configuration command\n", dev->name);
    adapter->tx_pcb.command = CMD_CONFIGURE_ADAPTER_MEMORY;
    adapter->tx_pcb.data.memconf.cmd_q = 10;
    adapter->tx_pcb.data.memconf.rcv_q = 20;
    adapter->tx_pcb.data.memconf.mcast = 10;
    adapter->tx_pcb.data.memconf.frame = 20;
    adapter->tx_pcb.data.memconf.rcv_b = 20;
    adapter->tx_pcb.data.memconf.progs = 0;
    adapter->tx_pcb.length = sizeof(struct Memconf);
    adapter->got[CMD_CONFIGURE_ADAPTER_MEMORY] = 0;
    if (!send_pcb(dev, &adapter->tx_pcb))
        pr_err("%s: couldn't send memory configuration command\n", dev->name);
    else {
        unsigned long timeout = jiffies + TIMEOUT;
        while (adapter->got[CMD_CONFIGURE_ADAPTER_MEMORY] == 0 && time_before(jiffies, timeout));
        if (time_after_eq(jiffies, timeout))
            TIMEOUT_MSG(__LINE__);
    }


    /*
     * configure adapter to receive broadcast messages and wait for response
     */
    if (elp_debug >= 3)
        pr_debug("%s: sending 82586 configure command\n", dev->name);
    adapter->tx_pcb.command = CMD_CONFIGURE_82586;
    adapter->tx_pcb.data.configure = NO_LOOPBACK | RECV_BROAD;
    adapter->tx_pcb.length = 2;
    adapter->got[CMD_CONFIGURE_82586] = 0;
    if (!send_pcb(dev, &adapter->tx_pcb))
        pr_err("%s: couldn't send 82586 configure command\n", dev->name);
    else {
        unsigned long timeout = jiffies + TIMEOUT;
        while (adapter->got[CMD_CONFIGURE_82586] == 0 && time_before(jiffies, timeout));
        if (time_after_eq(jiffies, timeout))
            TIMEOUT_MSG(__LINE__);
    }

    /* enable burst-mode DMA */
    /* outb(0x1, dev->base_addr + PORT_AUXDMA); */

    /*
     * queue receive commands to provide buffering
     */
    prime_rx(dev);
    if (elp_debug >= 3)
        pr_debug("%s: %d receive PCBs active\n", dev->name, adapter->rx_active);

    /*
     * device is now officially open!
     */

    netif_start_queue(dev);
    return 0;
}


/******************************************************
 *
 * send a packet to the adapter
 *
 ******************************************************/

static netdev_tx_t send_packet(struct net_device *dev, struct sk_buff *skb)
{
    elp_device *adapter = netdev_priv(dev);
    unsigned long target;
    unsigned long flags;

    /*
     * make sure the length is even and no shorter than 60 bytes
     */
    unsigned int nlen = (((skb->len < 60) ? 60 : skb->len) + 1) & (~1);

    if (test_and_set_bit(0, (void *) &adapter->busy)) {
        if (elp_debug >= 2)
            pr_debug("%s: transmit blocked\n", dev->name);
        return false;
    }

    dev->stats.tx_bytes += nlen;

    /*
     * send the adapter a transmit packet command. Ignore segment and offset
     * and make sure the length is even
     */
    adapter->tx_pcb.command = CMD_TRANSMIT_PACKET;
    adapter->tx_pcb.length = sizeof(struct Xmit_pkt);
    adapter->tx_pcb.data.xmit_pkt.buf_ofs
        = adapter->tx_pcb.data.xmit_pkt.buf_seg = 0;    /* Unused */
    adapter->tx_pcb.data.xmit_pkt.pkt_len = nlen;

    if (!send_pcb(dev, &adapter->tx_pcb)) {
        adapter->busy = 0;
        return false;
    }
    /* if this happens, we die */
    if (test_and_set_bit(0, (void *) &adapter->dmaing))
        pr_debug("%s: tx: DMA %d in progress\n", dev->name, adapter->current_dma.direction);

    adapter->current_dma.direction = 1;
    adapter->current_dma.start_time = jiffies;

    if ((unsigned long)(skb->data + nlen) >= MAX_DMA_ADDRESS || nlen != skb->len) {
        skb_copy_from_linear_data(skb, adapter->dma_buffer, nlen);
        memset(adapter->dma_buffer+skb->len, 0, nlen-skb->len);
        target = isa_virt_to_bus(adapter->dma_buffer);
    }
    else {
        target = isa_virt_to_bus(skb->data);
    }
    adapter->current_dma.skb = skb;

    flags=claim_dma_lock();
    disable_dma(dev->dma);
    clear_dma_ff(dev->dma);
    set_dma_mode(dev->dma, 0x48);   /* dma memory -> io */
    set_dma_addr(dev->dma, target);
    set_dma_count(dev->dma, nlen);
    outb_control(adapter->hcr_val | DMAE | TCEN, dev);
    enable_dma(dev->dma);
    release_dma_lock(flags);

    if (elp_debug >= 3)
        pr_debug("%s: DMA transfer started\n", dev->name);

    return true;
}

/*
 *  The upper layer thinks we timed out
 */

static void elp_timeout(struct net_device *dev)
{
    int stat;

    stat = inb_status(dev->base_addr);
    pr_warning("%s: transmit timed out, lost %s?\n", dev->name,
           (stat & ACRF) ? "interrupt" : "command");
    if (elp_debug >= 1)
        pr_debug("%s: status %#02x\n", dev->name, stat);
    dev->trans_start = jiffies; /* prevent tx timeout */
    dev->stats.tx_dropped++;
    netif_wake_queue(dev);
}

/******************************************************
 *
 * start the transmitter
 *    return 0 if sent OK, else return 1
 *
 ******************************************************/

static netdev_tx_t elp_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
    unsigned long flags;
    elp_device *adapter = netdev_priv(dev);

    spin_lock_irqsave(&adapter->lock, flags);
    check_3c505_dma(dev);

    if (elp_debug >= 3)
        pr_debug("%s: request to send packet of length %d\n", dev->name, (int) skb->len);

    netif_stop_queue(dev);

    /*
     * send the packet at skb->data for skb->len
     */
    if (!send_packet(dev, skb)) {
        if (elp_debug >= 2) {
            pr_debug("%s: failed to transmit packet\n", dev->name);
        }
        spin_unlock_irqrestore(&adapter->lock, flags);
        return NETDEV_TX_BUSY;
    }
    if (elp_debug >= 3)
        pr_debug("%s: packet of length %d sent\n", dev->name, (int) skb->len);

    prime_rx(dev);
    spin_unlock_irqrestore(&adapter->lock, flags);
    netif_start_queue(dev);
    return NETDEV_TX_OK;
}

/******************************************************
 *
 * return statistics on the board
 *
 ******************************************************/

static struct net_device_stats *elp_get_stats(struct net_device *dev)
{
    elp_device *adapter = netdev_priv(dev);

    if (elp_debug >= 3)
        pr_debug("%s: request for stats\n", dev->name);

    /* If the device is closed, just return the latest stats we have,
       - we cannot ask from the adapter without interrupts */
    if (!netif_running(dev))
        return &dev->stats;

    /* send a get statistics command to the board */
    adapter->tx_pcb.command = CMD_NETWORK_STATISTICS;
    adapter->tx_pcb.length = 0;
    adapter->got[CMD_NETWORK_STATISTICS] = 0;
    if (!send_pcb(dev, &adapter->tx_pcb))
        pr_err("%s: couldn't send get statistics command\n", dev->name);
    else {
        unsigned long timeout = jiffies + TIMEOUT;
        while (adapter->got[CMD_NETWORK_STATISTICS] == 0 && time_before(jiffies, timeout));
        if (time_after_eq(jiffies, timeout)) {
            TIMEOUT_MSG(__LINE__);
            return &dev->stats;
        }
    }

    /* statistics are now up to date */
    return &dev->stats;
}


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,
};

/******************************************************
 *
 * close the board
 *
 ******************************************************/

static int elp_close(struct net_device *dev)
{
    elp_device *adapter = netdev_priv(dev);

    if (elp_debug >= 3)
        pr_debug("%s: request to close device\n", dev->name);

    netif_stop_queue(dev);

    /* Someone may request the device statistic information even when
     * the interface is closed. The following will update the statistics
     * structure in the driver, so we'll be able to give current statistics.
     */
    (void) elp_get_stats(dev);

    /*
     * disable interrupts on the board
     */
    outb_control(0, dev);

    /*
     * release the IRQ
     */
    free_irq(dev->irq, dev);

    free_dma(dev->dma);
    free_pages((unsigned long) adapter->dma_buffer, get_order(DMA_BUFFER_SIZE));

    return 0;
}


/************************************************************
 *
 * Set multicast list
 * num_addrs==0: clear mc_list
 * num_addrs==-1: set promiscuous mode
 * num_addrs>0: set mc_list
 *
 ************************************************************/

static void elp_set_mc_list(struct net_device *dev)
{
    elp_device *adapter = netdev_priv(dev);
    struct netdev_hw_addr *ha;
    int i;
    unsigned long flags;

    if (elp_debug >= 3)
        pr_debug("%s: request to set multicast list\n", dev->name);

    spin_lock_irqsave(&adapter->lock, flags);

    if (!(dev->flags & (IFF_PROMISC | IFF_ALLMULTI))) {
        /* send a "load multicast list" command to the board, max 10 addrs/cmd */
        /* if num_addrs==0 the list will be cleared */
        adapter->tx_pcb.command = CMD_LOAD_MULTICAST_LIST;
        adapter->tx_pcb.length = 6 * netdev_mc_count(dev);
        i = 0;
        netdev_for_each_mc_addr(ha, dev)
            memcpy(adapter->tx_pcb.data.multicast[i++],
                   ha->addr, 6);
        adapter->got[CMD_LOAD_MULTICAST_LIST] = 0;
        if (!send_pcb(dev, &adapter->tx_pcb))
            pr_err("%s: couldn't send set_multicast command\n", dev->name);
        else {
            unsigned long timeout = jiffies + TIMEOUT;
            while (adapter->got[CMD_LOAD_MULTICAST_LIST] == 0 && time_before(jiffies, timeout));
            if (time_after_eq(jiffies, timeout)) {
                TIMEOUT_MSG(__LINE__);
            }
        }
        if (!netdev_mc_empty(dev))
            adapter->tx_pcb.data.configure = NO_LOOPBACK | RECV_BROAD | RECV_MULTI;
        else        /* num_addrs == 0 */
            adapter->tx_pcb.data.configure = NO_LOOPBACK | RECV_BROAD;
    } else
        adapter->tx_pcb.data.configure = NO_LOOPBACK | RECV_PROMISC;
    /*
     * configure adapter to receive messages (as specified above)
     * and wait for response
     */
    if (elp_debug >= 3)
        pr_debug("%s: sending 82586 configure command\n", dev->name);
    adapter->tx_pcb.command = CMD_CONFIGURE_82586;
    adapter->tx_pcb.length = 2;
    adapter->got[CMD_CONFIGURE_82586] = 0;
    if (!send_pcb(dev, &adapter->tx_pcb))
    {
        spin_unlock_irqrestore(&adapter->lock, flags);
        pr_err("%s: couldn't send 82586 configure command\n", dev->name);
    }
    else {
        unsigned long timeout = jiffies + TIMEOUT;
        spin_unlock_irqrestore(&adapter->lock, flags);
        while (adapter->got[CMD_CONFIGURE_82586] == 0 && time_before(jiffies, timeout));
        if (time_after_eq(jiffies, timeout))
            TIMEOUT_MSG(__LINE__);
    }
}

/************************************************************
 *
 * A couple of tests to see if there's 3C505 or not
 * Called only by elp_autodetect
 ************************************************************/

static int __init elp_sense(struct net_device *dev)
{
    int addr = dev->base_addr;
    const char *name = dev->name;
    byte orig_HSR;

    if (!request_region(addr, ELP_IO_EXTENT, "3c505"))
        return -ENODEV;

    orig_HSR = inb_status(addr);

    if (elp_debug > 0)
        pr_debug(search_msg, name, addr);

    if (orig_HSR == 0xff) {
        if (elp_debug > 0)
            pr_cont(notfound_msg, 1);
        goto out;
    }

    /* Wait for a while; the adapter may still be booting up */
    if (elp_debug > 0)
        pr_cont(stilllooking_msg);

    if (orig_HSR & DIR) {
        /* If HCR.DIR is up, we pull it down. HSR.DIR should follow. */
        outb(0, dev->base_addr + PORT_CONTROL);
        msleep(300);
        if (inb_status(addr) & DIR) {
            if (elp_debug > 0)
                pr_cont(notfound_msg, 2);
            goto out;
        }
    } else {
        /* If HCR.DIR is down, we pull it up. HSR.DIR should follow. */
        outb(DIR, dev->base_addr + PORT_CONTROL);
        msleep(300);
        if (!(inb_status(addr) & DIR)) {
            if (elp_debug > 0)
                pr_cont(notfound_msg, 3);
            goto out;
        }
    }
    /*
     * It certainly looks like a 3c505.
     */
    if (elp_debug > 0)
        pr_cont(found_msg);

    return 0;
out:
    release_region(addr, ELP_IO_EXTENT);
    return -ENODEV;
}

/*************************************************************
 *
 * Search through addr_list[] and try to find a 3C505
 * Called only by eplus_probe
 *************************************************************/

static int __init elp_autodetect(struct net_device *dev)
{
    int idx = 0;

    /* if base address set, then only check that address
       otherwise, run through the table */
    if (dev->base_addr != 0) {  /* dev->base_addr == 0 ==> plain autodetect */
        if (elp_sense(dev) == 0)
            return dev->base_addr;
    } else
        while ((dev->base_addr = addr_list[idx++])) {
            if (elp_sense(dev) == 0)
                return dev->base_addr;
        }

    /* could not find an adapter */
    if (elp_debug > 0)
        pr_debug(couldnot_msg, dev->name);

    return 0;       /* Because of this, the layer above will return -ENODEV */
}

static const struct net_device_ops elp_netdev_ops = {
    .ndo_open       = elp_open,
    .ndo_stop       = elp_close,
    .ndo_get_stats      = elp_get_stats,
    .ndo_start_xmit     = elp_start_xmit,
    .ndo_tx_timeout     = elp_timeout,
    .ndo_set_rx_mode    = elp_set_mc_list,
    .ndo_change_mtu     = eth_change_mtu,
    .ndo_set_mac_address    = eth_mac_addr,
    .ndo_validate_addr  = eth_validate_addr,
};

/******************************************************
 *
 * probe for an Etherlink Plus board at the specified address
 *
 ******************************************************/

/* There are three situations we need to be able to detect here:

 *  a) the card is idle
 *  b) the card is still booting up
 *  c) the card is stuck in a strange state (some DOS drivers do this)
 *
 * In case (a), all is well.  In case (b), we wait 10 seconds to see if the
 * card finishes booting, and carry on if so.  In case (c), we do a hard reset,
 * loop round, and hope for the best.
 *
 * This is all very unpleasant, but hopefully avoids the problems with the old
 * probe code (which had a 15-second delay if the card was idle, and didn't
 * work at all if it was in a weird state).
 */

static int __init elplus_setup(struct net_device *dev)
{
    elp_device *adapter = netdev_priv(dev);
    int i, tries, tries1, okay;
    unsigned long timeout;
    unsigned long cookie = 0;
    int err = -ENODEV;

    /*
     *  setup adapter structure
     */

    dev->base_addr = elp_autodetect(dev);
    if (!dev->base_addr)
        return -ENODEV;

    adapter->send_pcb_semaphore = 0;

    for (tries1 = 0; tries1 < 3; tries1++) {
        outb_control((adapter->hcr_val | CMDE) & ~DIR, dev);
        /* First try to write just one byte, to see if the card is
         * responding at all normally.
         */
        timeout = jiffies + 5*HZ/100;
        okay = 0;
        while (time_before(jiffies, timeout) && !(inb_status(dev->base_addr) & HCRE));
        if ((inb_status(dev->base_addr) & HCRE)) {
            outb_command(0, dev->base_addr);    /* send a spurious byte */
            timeout = jiffies + 5*HZ/100;
            while (time_before(jiffies, timeout) && !(inb_status(dev->base_addr) & HCRE));
            if (inb_status(dev->base_addr) & HCRE)
                okay = 1;
        }
        if (!okay) {
            /* Nope, it's ignoring the command register.  This means that
             * either it's still booting up, or it's died.
             */
            pr_err("%s: command register wouldn't drain, ", dev->name);
            if ((inb_status(dev->base_addr) & 7) == 3) {
                /* If the adapter status is 3, it *could* still be booting.
                 * Give it the benefit of the doubt for 10 seconds.
                 */
                pr_cont("assuming 3c505 still starting\n");
                timeout = jiffies + 10*HZ;
                while (time_before(jiffies, timeout) && (inb_status(dev->base_addr) & 7));
                if (inb_status(dev->base_addr) & 7) {
                    pr_err("%s: 3c505 failed to start\n", dev->name);
                } else {
                    okay = 1;  /* It started */
                }
            } else {
                /* Otherwise, it must just be in a strange
                 * state.  We probably need to kick it.
                 */
                pr_cont("3c505 is sulking\n");
            }
        }
        for (tries = 0; tries < 5 && okay; tries++) {

            /*
             * Try to set the Ethernet address, to make sure that the board
             * is working.
             */
            adapter->tx_pcb.command = CMD_STATION_ADDRESS;
            adapter->tx_pcb.length = 0;
            cookie = probe_irq_on();
            if (!send_pcb(dev, &adapter->tx_pcb)) {
                pr_err("%s: could not send first PCB\n", dev->name);
                probe_irq_off(cookie);
                continue;
            }
            if (!receive_pcb(dev, &adapter->rx_pcb)) {
                pr_err("%s: could not read first PCB\n", dev->name);
                probe_irq_off(cookie);
                continue;
            }
            if ((adapter->rx_pcb.command != CMD_ADDRESS_RESPONSE) ||
                (adapter->rx_pcb.length != 6)) {
                pr_err("%s: first PCB wrong (%d, %d)\n", dev->name,
                    adapter->rx_pcb.command, adapter->rx_pcb.length);
                probe_irq_off(cookie);
                continue;
            }
            goto okay;
        }
        /* It's broken.  Do a hard reset to re-initialise the board,
         * and try again.
         */
        pr_info("%s: resetting adapter\n", dev->name);
        outb_control(adapter->hcr_val | FLSH | ATTN, dev);
        outb_control(adapter->hcr_val & ~(FLSH | ATTN), dev);
    }
    pr_err("%s: failed to initialise 3c505\n", dev->name);
    goto out;

      okay:
    if (dev->irq) {     /* Is there a preset IRQ? */
        int rpt = probe_irq_off(cookie);
        if (dev->irq != rpt) {
            pr_warning("%s: warning, irq %d configured but %d detected\n", dev->name, dev->irq, rpt);
        }
        /* if dev->irq == probe_irq_off(cookie), all is well */
    } else             /* No preset IRQ; just use what we can detect */
        dev->irq = probe_irq_off(cookie);
    switch (dev->irq) {    /* Legal, sane? */
    case 0:
        pr_err("%s: IRQ probe failed: check 3c505 jumpers.\n",
               dev->name);
        goto out;
    case 1:
    case 6:
    case 8:
    case 13:
        pr_err("%s: Impossible IRQ %d reported by probe_irq_off().\n",
               dev->name, dev->irq);
               goto out;
    }
    /*
     *  Now we have the IRQ number so we can disable the interrupts from
     *  the board until the board is opened.
     */
    outb_control(adapter->hcr_val & ~CMDE, dev);

    /*
     * copy Ethernet address into structure
     */
    for (i = 0; i < 6; i++)
        dev->dev_addr[i] = adapter->rx_pcb.data.eth_addr[i];

    /* find a DMA channel */
    if (!dev->dma) {
        if (dev->mem_start) {
            dev->dma = dev->mem_start & 7;
        }
        else {
            pr_warning("%s: warning, DMA channel not specified, using default\n", dev->name);
            dev->dma = ELP_DMA;
        }
    }

    /*
     * print remainder of startup message
     */
    pr_info("%s: 3c505 at %#lx, irq %d, dma %d, addr %pM, ",
        dev->name, dev->base_addr, dev->irq, dev->dma, dev->dev_addr);
    /*
     * read more information from the adapter
     */

    adapter->tx_pcb.command = CMD_ADAPTER_INFO;
    adapter->tx_pcb.length = 0;
    if (!send_pcb(dev, &adapter->tx_pcb) ||
        !receive_pcb(dev, &adapter->rx_pcb) ||
        (adapter->rx_pcb.command != CMD_ADAPTER_INFO_RESPONSE) ||
        (adapter->rx_pcb.length != 10)) {
        pr_cont("not responding to second PCB\n");
    }
    pr_cont("rev %d.%d, %dk\n", adapter->rx_pcb.data.info.major_vers,
        adapter->rx_pcb.data.info.minor_vers, adapter->rx_pcb.data.info.RAM_sz);

    /*
     * reconfigure the adapter memory to better suit our purposes
     */
    adapter->tx_pcb.command = CMD_CONFIGURE_ADAPTER_MEMORY;
    adapter->tx_pcb.length = 12;
    adapter->tx_pcb.data.memconf.cmd_q = 8;
    adapter->tx_pcb.data.memconf.rcv_q = 8;
    adapter->tx_pcb.data.memconf.mcast = 10;
    adapter->tx_pcb.data.memconf.frame = 10;
    adapter->tx_pcb.data.memconf.rcv_b = 10;
    adapter->tx_pcb.data.memconf.progs = 0;
    if (!send_pcb(dev, &adapter->tx_pcb) ||
        !receive_pcb(dev, &adapter->rx_pcb) ||
        (adapter->rx_pcb.command != CMD_CONFIGURE_ADAPTER_RESPONSE) ||
        (adapter->rx_pcb.length != 2)) {
        pr_err("%s: could not configure adapter memory\n", dev->name);
    }
    if (adapter->rx_pcb.data.configure) {
        pr_err("%s: adapter configuration failed\n", dev->name);
    }

    dev->netdev_ops = &elp_netdev_ops;
    dev->watchdog_timeo = 10*HZ;
    dev->ethtool_ops = &netdev_ethtool_ops;     /* local */

    dev->mem_start = dev->mem_end = 0;

    err = register_netdev(dev);
    if (err)
        goto out;

    return 0;
out:
    release_region(dev->base_addr, ELP_IO_EXTENT);
    return err;
}

#ifndef MODULE
struct net_device * __init elplus_probe(int unit)
{
    struct net_device *dev = alloc_etherdev(sizeof(elp_device));
    int err;
    if (!dev)
        return ERR_PTR(-ENOMEM);

    sprintf(dev->name, "eth%d", unit);
    netdev_boot_setup_check(dev);

    err = elplus_setup(dev);
    if (err) {
        free_netdev(dev);
        return ERR_PTR(err);
    }
    return dev;
}

#else
static struct net_device *dev_3c505[ELP_MAX_CARDS];
static int io[ELP_MAX_CARDS];
static int irq[ELP_MAX_CARDS];
static int dma[ELP_MAX_CARDS];
module_param_array(io, int, NULL, 0);
module_param_array(irq, int, NULL, 0);
module_param_array(dma, int, NULL, 0);
MODULE_PARM_DESC(io, "EtherLink Plus I/O base address(es)");
MODULE_PARM_DESC(irq, "EtherLink Plus IRQ number(s) (assigned)");
MODULE_PARM_DESC(dma, "EtherLink Plus DMA channel(s)");

int __init init_module(void)
{
    int this_dev, found = 0;

    for (this_dev = 0; this_dev < ELP_MAX_CARDS; this_dev++) {
        struct net_device *dev = alloc_etherdev(sizeof(elp_device));
        if (!dev)
            break;

        dev->irq = irq[this_dev];
        dev->base_addr = io[this_dev];
        if (dma[this_dev]) {
            dev->dma = dma[this_dev];
        } else {
            dev->dma = ELP_DMA;
            pr_warning("3c505.c: warning, using default DMA channel,\n");
        }
        if (io[this_dev] == 0) {
            if (this_dev) {
                free_netdev(dev);
                break;
            }
            pr_notice("3c505.c: module autoprobe not recommended, give io=xx.\n");
        }
        if (elplus_setup(dev) != 0) {
            pr_warning("3c505.c: Failed to register card at 0x%x.\n", io[this_dev]);
            free_netdev(dev);
            break;
        }
        dev_3c505[this_dev] = dev;
        found++;
    }
    if (!found)
        return -ENODEV;
    return 0;
}

void __exit cleanup_module(void)
{
    int this_dev;

    for (this_dev = 0; this_dev < ELP_MAX_CARDS; this_dev++) {
        struct net_device *dev = dev_3c505[this_dev];
        if (dev) {
            unregister_netdev(dev);
            release_region(dev->base_addr, ELP_IO_EXTENT);
            free_netdev(dev);
        }
    }
}

#endif              /* MODULE */
MODULE_LICENSE("GPL");