/*
 * 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, <craigs@ineluki.apana.org.au>
 *              Final debugging by
 *                      Andrew Tridgell, <tridge@nimbus.anu.edu.au>
 *              Auto irq/address, tuning, cleanup and v1.1.4+ kernel mods by
 *                      Juha Laiho, <jlaiho@ichaos.nullnet.fi>
 *              Linux 3C509 driver by
 *                      Donald Becker, <becker@super.org>
 *                      (Now at <becker@scyld.com>)
 *              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 krus@diku.dk.
 *              3C505 technical information provided by
 *                      Terry Murphy, of 3Com Network Adapter Division
 *              Linux 1.3.0 changes by
 *                      Alan Cox <Alan.Cox@linux.org>
 *              More debugging, DMA support, currently maintained by
 *                      Philip Blundell <philb@gnu.org>
 *              Multicard/soft configurable dma channel/rev 2 hardware support
 *                      by Christopher Collins <ccollins@pcug.org.au>
 *              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/slab.h>
#include <linux/ioport.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 <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
 *
 *********************************************************/

static const char filename[] = __FILE__;

static const char timeout_msg[] = "*** timeout at %s:%s (line %d) ***\n";
#define TIMEOUT_MSG(lineno) \
        printk(timeout_msg, filename,__FUNCTION__,(lineno))

static const char invalid_pcb_msg[] =
"*** invalid pcb length %d at %s:%s (line %d) ***\n";
#define INVALID_PCB_MSG(len) \
        printk(invalid_pcb_msg, (len),filename,__FUNCTION__,__LINE__)

static char search_msg[] __initdata = KERN_INFO "%s: Looking for 3c505 adapter at address %#x...";

static char stilllooking_msg[] __initdata = "still looking...";

static char found_msg[] __initdata = "found.\n";

static char notfound_msg[] __initdata = "not found (reason = %d)\n";

static char couldnot_msg[] __initdata = KERN_INFO "%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 *)(dev->priv))->hcr_val = val;
}

#define HCR_VAL(x)   (((elp_device *)((x)->priv))->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 = dev->priv;
        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 = dev->priv;
        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))
                printk(KERN_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 = dev->priv;
        if (adapter->dmaing && time_after(jiffies, adapter->current_dma.start_time + 10)) {
                unsigned long flags, f;
                printk(KERN_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;
        }
        printk(KERN_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;
        }
        printk(KERN_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 = dev->priv;
        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 = dev->priv;
        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) {
                        printk(KERN_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
                        printk(KERN_DEBUG "%s: send_pcb got NAK\n", dev->name);
#endif
                        goto abort;
                }
        }

        if (elp_debug >= 1)
                printk(KERN_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 = dev->priv;

        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__);
                printk(KERN_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);
        i = 0;
        do {
                j = 0;
                while (((stat = get_status(dev->base_addr)) & ACRF) == 0 && j++ < 20000);
                pcb->data.raw[i++] = inb_command(dev->base_addr);
                if (i > MAX_PCB_DATA)
                        INVALID_PCB_MSG(i);
        } while ((stat & ASF_PCB_MASK) != ASF_PCB_END && j < 20000);
        spin_unlock_irqrestore(&adapter->lock, flags);
        if (j >= 20000) {
                TIMEOUT_MSG(__LINE__);
                return false;
        }
        /* woops, 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)
                        printk(KERN_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);
                                printk(KERN_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 = dev->priv;

        if (elp_debug >= 3)
                printk(KERN_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 = dev->priv;
        void *target;
        struct sk_buff *skb;
        unsigned long flags;

        rlen = (len + 1) & ~1;
        skb = dev_alloc_skb(rlen + 2);

        if (!skb) {
                printk(KERN_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))
                printk(KERN_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) {
                printk(KERN_DEBUG "%s: rx DMA transfer started\n", dev->name);
        }

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

        if (!adapter->busy)
                printk(KERN_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;
        elp_device *adapter;
        unsigned long timeout;

        dev = dev_id;
        adapter = (elp_device *) dev->priv;

        spin_lock(&adapter->lock);

        do {
                /*
                 * has a DMA transfer finished?
                 */
                if (inb_status(dev->base_addr) & DONE) {
                        if (!adapter->dmaing) {
                                printk(KERN_WARNING "%s: phantom DMA completed\n", dev->name);
                        }
                        if (elp_debug >= 3) {
                                printk(KERN_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);
                                        adapter->stats.rx_bytes += skb->len;
                                        netif_rx(skb);
                                        dev->last_rx = jiffies;
                                }
                        }
                        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)
                                        printk(KERN_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) {
                                                printk(KERN_ERR "%s: interrupt - packet not received correctly\n", dev->name);
                                        } else {
                                                if (elp_debug >= 3) {
                                                        printk(KERN_DEBUG "%s: interrupt - packet received of length %i (%i)\n", dev->name, len, dlen);
                                                }
                                                if (adapter->irx_pcb.command == 0xff) {
                                                        if (elp_debug >= 2)
                                                                printk(KERN_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)
                                                        printk(KERN_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)
                                                printk(KERN_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)
                                                printk(KERN_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)
                                                printk(KERN_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)
                                                printk(KERN_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:
                                        adapter->stats.rx_packets += adapter->irx_pcb.data.netstat.tot_recv;
                                        adapter->stats.tx_packets += adapter->irx_pcb.data.netstat.tot_xmit;
                                        adapter->stats.rx_crc_errors += adapter->irx_pcb.data.netstat.err_CRC;
                                        adapter->stats.rx_frame_errors += adapter->irx_pcb.data.netstat.err_align;
                                        adapter->stats.rx_fifo_errors += adapter->irx_pcb.data.netstat.err_ovrrun;
                                        adapter->stats.rx_over_errors += adapter->irx_pcb.data.netstat.err_res;
                                        adapter->got[CMD_NETWORK_STATISTICS] = 1;
                                        if (elp_debug >= 3)
                                                printk(KERN_DEBUG "%s: interrupt - statistics response received\n", dev->name);
                                        break;

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

                                        /*
                                         * some unknown PCB
                                         */
                                default:
                                        printk(KERN_DEBUG "%s: unknown PCB received - %2.2x\n", dev->name, adapter->irx_pcb.command);
                                        break;
                                }
                        } else {
                                printk(KERN_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;
        int retval;

        adapter = dev->priv;

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

        /*
         * make sure we actually found the device
         */
        if (adapter == NULL) {
                printk(KERN_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))) {
                printk(KERN_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);
                printk(KERN_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) {
                printk(KERN_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)
                printk(KERN_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))
                printk(KERN_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)
                printk(KERN_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))
                printk(KERN_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)
                printk(KERN_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 bool send_packet(struct net_device *dev, struct sk_buff *skb)
{
        elp_device *adapter = dev->priv;
        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)
                        printk(KERN_DEBUG "%s: transmit blocked\n", dev->name);
                return false;
        }

        adapter->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))
                printk(KERN_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)
                printk(KERN_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)
{
        elp_device *adapter = dev->priv;
        int stat;

        stat = inb_status(dev->base_addr);
        printk(KERN_WARNING "%s: transmit timed out, lost %s?\n", dev->name, (stat & ACRF) ? "interrupt" : "command");
        if (elp_debug >= 1)
                printk(KERN_DEBUG "%s: status %#02x\n", dev->name, stat);
        dev->trans_start = jiffies;
        adapter->stats.tx_dropped++;
        netif_wake_queue(dev);
}

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

static int elp_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        unsigned long flags;
        elp_device *adapter = dev->priv;

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

        if (elp_debug >= 3)
                printk(KERN_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) {
                        printk(KERN_DEBUG "%s: failed to transmit packet\n", dev->name);
                }
                spin_unlock_irqrestore(&adapter->lock, flags);
                return 1;
        }
        if (elp_debug >= 3)
                printk(KERN_DEBUG "%s: packet of length %d sent\n", dev->name, (int) skb->len);

        /*
         * start the transmit timeout
         */
        dev->trans_start = jiffies;

        prime_rx(dev);
        spin_unlock_irqrestore(&adapter->lock, flags);
        netif_start_queue(dev);
        return 0;
}

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

static struct net_device_stats *elp_get_stats(struct net_device *dev)
{
        elp_device *adapter = (elp_device *) dev->priv;

        if (elp_debug >= 3)
                printk(KERN_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 &adapter->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))
                printk(KERN_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 &adapter->stats;
                }
        }

        /* statistics are now up to date */
        return &adapter->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;

        adapter = dev->priv;

        if (elp_debug >= 3)
                printk(KERN_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 = (elp_device *) dev->priv;
        struct dev_mc_list *dmi = dev->mc_list;
        int i;
        unsigned long flags;

        if (elp_debug >= 3)
                printk(KERN_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 * dev->mc_count;
                for (i = 0; i < dev->mc_count; i++) {
                        memcpy(adapter->tx_pcb.data.multicast[i], dmi->dmi_addr, 6);
                        dmi = dmi->next;
                }
                adapter->got[CMD_LOAD_MULTICAST_LIST] = 0;
                if (!send_pcb(dev, &adapter->tx_pcb))
                        printk(KERN_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 (dev->mc_count)
                        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)
                printk(KERN_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);
                printk(KERN_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)
                printk(search_msg, name, addr);

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

        /* Wait for a while; the adapter may still be booting up */
        if (elp_debug > 0)
                printk(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)
                                printk(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)
                                printk(notfound_msg, 3);
                        goto out;
                }
        }
        /*
         * It certainly looks like a 3c505.
         */
        if (elp_debug > 0)
                printk(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)
                printk(couldnot_msg, dev->name);

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


/******************************************************
 *
 * 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 = dev->priv;
        int i, tries, tries1, okay;
        unsigned long timeout;
        unsigned long cookie = 0;
        int err = -ENODEV;
        DECLARE_MAC_BUF(mac);

        /*
         *  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.
                         */
                        printk(KERN_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.
                                 */
                                printk("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) {
                                        printk(KERN_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.
                                 */
                                printk("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)) {
                                printk(KERN_ERR "%s: could not send first PCB\n", dev->name);
                                probe_irq_off(cookie);
                                continue;
                        }
                        if (!receive_pcb(dev, &adapter->rx_pcb)) {
                                printk(KERN_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)) {
                                printk(KERN_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.
                 */
                printk(KERN_INFO "%s: resetting adapter\n", dev->name);
                outb_control(adapter->hcr_val | FLSH | ATTN, dev);
                outb_control(adapter->hcr_val & ~(FLSH | ATTN), dev);
        }
        printk(KERN_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) {
                        printk(KERN_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:
                printk(KERN_ERR "%s: IRQ probe failed: check 3c505 jumpers.\n",
                       dev->name);
                goto out;
        case 1:
        case 6:
        case 8:
        case 13:
                printk(KERN_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 {
                        printk(KERN_WARNING "%s: warning, DMA channel not specified, using default\n", dev->name);
                        dev->dma = ELP_DMA;
                }
        }

        /*
         * print remainder of startup message
         */
        printk(KERN_INFO "%s: 3c505 at %#lx, irq %d, dma %d, "
               "addr %s, ",
               dev->name, dev->base_addr, dev->irq, dev->dma,
               print_mac(mac, 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)) {
                printk("not responding to second PCB\n");
        }
        printk("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)) {
                printk(KERN_ERR "%s: could not configure adapter memory\n", dev->name);
        }
        if (adapter->rx_pcb.data.configure) {
                printk(KERN_ERR "%s: adapter configuration failed\n", dev->name);
        }

        dev->open = elp_open;                           /* local */
        dev->stop = elp_close;                          /* local */
        dev->get_stats = elp_get_stats;                 /* local */
        dev->hard_start_xmit = elp_start_xmit;          /* local */
        dev->tx_timeout = elp_timeout;                  /* local */
        dev->watchdog_timeo = 10*HZ;
        dev->set_multicast_list = elp_set_mc_list;      /* local */
        dev->ethtool_ops = &netdev_ethtool_ops;         /* local */

        memset(&(adapter->stats), 0, sizeof(struct net_device_stats));
        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;
                        printk(KERN_WARNING "3c505.c: warning, using default DMA channel,\n");
                }
                if (io[this_dev] == 0) {
                        if (this_dev) {
                                free_netdev(dev);
                                break;
                        }
                        printk(KERN_NOTICE "3c505.c: module autoprobe not recommended, give io=xx.\n");
                }
                if (elplus_setup(dev) != 0) {
                        printk(KERN_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");