de620.c

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/*
 *  de620.c $Revision: 1.40 $ BETA
 *
 *
 *  Linux driver for the D-Link DE-620 Ethernet pocket adapter.
 *
 *  Portions (C) Copyright 1993, 1994 by Bjorn Ekwall <[email protected]>
 *
 *  Based on adapter information gathered from DOS packetdriver
 *  sources from D-Link Inc:  (Special thanks to Henry Ngai of D-Link.)
 *      Portions (C) Copyright D-Link SYSTEM Inc. 1991, 1992
 *      Copyright, 1988, Russell Nelson, Crynwr Software
 *
 *  Adapted to the sample network driver core for linux,
 *  written by: Donald Becker <[email protected]>
 *      (Now at <[email protected]>)
 *
 *  Valuable assistance from:
 *      J. Joshua Kopper <[email protected]>
 *      Olav Kvittem <[email protected]>
 *      Germano Caronni <[email protected]>
 *      Jeremy Fitzhardinge <[email protected]>
 *
 *****************************************************************************/
/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *****************************************************************************/
static const char version[] =
    "de620.c: $Revision: 1.40 $,  Bjorn Ekwall <[email protected]>\n";

/***********************************************************************
 *
 * "Tuning" section.
 *
 * Compile-time options: (see below for descriptions)
 * -DDE620_IO=0x378 (lpt1)
 * -DDE620_IRQ=7    (lpt1)
 * -DSHUTDOWN_WHEN_LOST
 * -DCOUNT_LOOPS
 * -DLOWSPEED
 * -DREAD_DELAY
 * -DWRITE_DELAY
 */

/*
 * This driver assumes that the printer port is a "normal",
 * dumb, uni-directional port!
 * If your port is "fancy" in any way, please try to set it to "normal"
 * with your BIOS setup.  I have no access to machines with bi-directional
 * ports, so I can't test such a driver :-(
 * (Yes, I _know_ it is possible to use DE620 with bidirectional ports...)
 *
 * There are some clones of DE620 out there, with different names.
 * If the current driver does not recognize a clone, try to change
 * the following #define to:
 *
 * #define DE620_CLONE 1
 */
#define DE620_CLONE 0

/*
 * If the adapter has problems with high speeds, enable this #define
 * otherwise full printerport speed will be attempted.
 *
 * You can tune the READ_DELAY/WRITE_DELAY below if you enable LOWSPEED
 *
#define LOWSPEED
 */

#ifndef READ_DELAY
#define READ_DELAY 100  /* adapter internal read delay in 100ns units */
#endif

#ifndef WRITE_DELAY
#define WRITE_DELAY 100 /* adapter internal write delay in 100ns units */
#endif

/*
 * Enable this #define if you want the adapter to do a "ifconfig down" on
 * itself when we have detected that something is possibly wrong with it.
 * The default behaviour is to retry with "adapter_init()" until success.
 * This should be used for debugging purposes only.
 *
#define SHUTDOWN_WHEN_LOST
 */

#ifdef LOWSPEED
/*
 * Enable this #define if you want to see debugging output that show how long
 * we have to wait before the DE-620 is ready for the next read/write/command.
 *
#define COUNT_LOOPS
 */
#endif

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>

#include <asm/io.h>

/* Constant definitions for the DE-620 registers, commands and bits */
#include "de620.h"

typedef unsigned char byte;

/*******************************************************
 *                                                     *
 * Definition of D-Link DE-620 Ethernet Pocket adapter *
 * See also "de620.h"                                  *
 *                                                     *
 *******************************************************/
#ifndef DE620_IO /* Compile-time configurable */
#define DE620_IO 0x378
#endif

#ifndef DE620_IRQ /* Compile-time configurable */
#define DE620_IRQ   7
#endif

#define DATA_PORT   (dev->base_addr)
#define STATUS_PORT (dev->base_addr + 1)
#define COMMAND_PORT    (dev->base_addr + 2)

#define RUNT 60     /* Too small Ethernet packet */
#define GIANT 1514  /* largest legal size packet, no fcs */

/*
 * Force media with insmod:
 *  insmod de620.o bnc=1
 * or
 *  insmod de620.o utp=1
 *
 * Force io and/or irq with insmod:
 *  insmod de620.o io=0x378 irq=7
 *
 * Make a clone skip the Ethernet-address range check:
 *  insmod de620.o clone=1
 */
static int bnc;
static int utp;
static int io  = DE620_IO;
static int irq = DE620_IRQ;
static int clone = DE620_CLONE;

static spinlock_t de620_lock;

module_param(bnc, int, 0);
module_param(utp, int, 0);
module_param(io, int, 0);
module_param(irq, int, 0);
module_param(clone, int, 0);
MODULE_PARM_DESC(bnc, "DE-620 set BNC medium (0-1)");
MODULE_PARM_DESC(utp, "DE-620 set UTP medium (0-1)");
MODULE_PARM_DESC(io, "DE-620 I/O base address,required");
MODULE_PARM_DESC(irq, "DE-620 IRQ number,required");
MODULE_PARM_DESC(clone, "Check also for non-D-Link DE-620 clones (0-1)");

/***********************************************
 *                                             *
 * Index to functions, as function prototypes. *
 *                                             *
 ***********************************************/

/*
 * Routines used internally. (See also "convenience macros.. below")
 */

/* Put in the device structure. */
static int  de620_open(struct net_device *);
static int  de620_close(struct net_device *);
static void de620_set_multicast_list(struct net_device *);
static int  de620_start_xmit(struct sk_buff *, struct net_device *);

/* Dispatch from interrupts. */
static irqreturn_t de620_interrupt(int, void *);
static int  de620_rx_intr(struct net_device *);

/* Initialization */
static int  adapter_init(struct net_device *);
static int  read_eeprom(struct net_device *);


/*
 * D-Link driver variables:
 */
#define SCR_DEF NIBBLEMODE |INTON | SLEEP | AUTOTX
#define TCR_DEF RXPB            /* not used: | TXSUCINT | T16INT */
#define DE620_RX_START_PAGE 12      /* 12 pages (=3k) reserved for tx */
#define DEF_NIC_CMD IRQEN | ICEN | DS1

static volatile byte    NIC_Cmd;
static volatile byte    next_rx_page;
static byte     first_rx_page;
static byte     last_rx_page;
static byte     EIPRegister;

static struct nic {
    byte    NodeID[6];
    byte    RAM_Size;
    byte    Model;
    byte    Media;
    byte    SCR;
} nic_data;

/**********************************************************
 *                                                        *
 * Convenience macros/functions for D-Link DE-620 adapter *
 *                                                        *
 **********************************************************/
#define de620_tx_buffs(dd) (inb(STATUS_PORT) & (TXBF0 | TXBF1))
#define de620_flip_ds(dd) NIC_Cmd ^= DS0 | DS1; outb(NIC_Cmd, COMMAND_PORT);

/* Check for ready-status, and return a nibble (high 4 bits) for data input */
#ifdef COUNT_LOOPS
static int tot_cnt;
#endif
static inline byte
de620_ready(struct net_device *dev)
{
    byte value;
    register short int cnt = 0;

    while ((((value = inb(STATUS_PORT)) & READY) == 0) && (cnt <= 1000))
        ++cnt;

#ifdef COUNT_LOOPS
    tot_cnt += cnt;
#endif
    return value & 0xf0; /* nibble */
}

static inline void
de620_send_command(struct net_device *dev, byte cmd)
{
    de620_ready(dev);
    if (cmd == W_DUMMY)
        outb(NIC_Cmd, COMMAND_PORT);

    outb(cmd, DATA_PORT);

    outb(NIC_Cmd ^ CS0, COMMAND_PORT);
    de620_ready(dev);
    outb(NIC_Cmd, COMMAND_PORT);
}

static inline void
de620_put_byte(struct net_device *dev, byte value)
{
    /* The de620_ready() makes 7 loops, on the average, on a DX2/66 */
    de620_ready(dev);
    outb(value, DATA_PORT);
    de620_flip_ds(dev);
}

static inline byte
de620_read_byte(struct net_device *dev)
{
    byte value;

    /* The de620_ready() makes 7 loops, on the average, on a DX2/66 */
    value = de620_ready(dev); /* High nibble */
    de620_flip_ds(dev);
    value |= de620_ready(dev) >> 4; /* Low nibble */
    return value;
}

static inline void
de620_write_block(struct net_device *dev, byte *buffer, int count, int pad)
{
#ifndef LOWSPEED
    byte uflip = NIC_Cmd ^ (DS0 | DS1);
    byte dflip = NIC_Cmd;
#else /* LOWSPEED */
#ifdef COUNT_LOOPS
    int bytes = count;
#endif /* COUNT_LOOPS */
#endif /* LOWSPEED */

#ifdef LOWSPEED
#ifdef COUNT_LOOPS
    tot_cnt = 0;
#endif /* COUNT_LOOPS */
    /* No further optimization useful, the limit is in the adapter. */
    for ( ; count > 0; --count, ++buffer) {
        de620_put_byte(dev,*buffer);
    }
    for ( count = pad ; count > 0; --count, ++buffer) {
        de620_put_byte(dev, 0);
    }
    de620_send_command(dev,W_DUMMY);
#ifdef COUNT_LOOPS
    /* trial debug output: loops per byte in de620_ready() */
    printk("WRITE(%d)\n", tot_cnt/((bytes?bytes:1)));
#endif /* COUNT_LOOPS */
#else /* not LOWSPEED */
    for ( ; count > 0; count -=2) {
        outb(*buffer++, DATA_PORT);
        outb(uflip, COMMAND_PORT);
        outb(*buffer++, DATA_PORT);
        outb(dflip, COMMAND_PORT);
    }
    de620_send_command(dev,W_DUMMY);
#endif /* LOWSPEED */
}

static inline void
de620_read_block(struct net_device *dev, byte *data, int count)
{
#ifndef LOWSPEED
    byte value;
    byte uflip = NIC_Cmd ^ (DS0 | DS1);
    byte dflip = NIC_Cmd;
#else /* LOWSPEED */
#ifdef COUNT_LOOPS
    int bytes = count;

    tot_cnt = 0;
#endif /* COUNT_LOOPS */
#endif /* LOWSPEED */

#ifdef LOWSPEED
    /* No further optimization useful, the limit is in the adapter. */
    while (count-- > 0) {
        *data++ = de620_read_byte(dev);
        de620_flip_ds(dev);
    }
#ifdef COUNT_LOOPS
    /* trial debug output: loops per byte in de620_ready() */
    printk("READ(%d)\n", tot_cnt/(2*(bytes?bytes:1)));
#endif /* COUNT_LOOPS */
#else /* not LOWSPEED */
    while (count-- > 0) {
        value = inb(STATUS_PORT) & 0xf0; /* High nibble */
        outb(uflip, COMMAND_PORT);
        *data++ = value | inb(STATUS_PORT) >> 4; /* Low nibble */
        outb(dflip , COMMAND_PORT);
    }
#endif /* LOWSPEED */
}

static inline void
de620_set_delay(struct net_device *dev)
{
    de620_ready(dev);
    outb(W_DFR, DATA_PORT);
    outb(NIC_Cmd ^ CS0, COMMAND_PORT);

    de620_ready(dev);
#ifdef LOWSPEED
    outb(WRITE_DELAY, DATA_PORT);
#else
    outb(0, DATA_PORT);
#endif
    de620_flip_ds(dev);

    de620_ready(dev);
#ifdef LOWSPEED
    outb(READ_DELAY, DATA_PORT);
#else
    outb(0, DATA_PORT);
#endif
    de620_flip_ds(dev);
}

static inline void
de620_set_register(struct net_device *dev, byte reg, byte value)
{
    de620_ready(dev);
    outb(reg, DATA_PORT);
    outb(NIC_Cmd ^ CS0, COMMAND_PORT);

    de620_put_byte(dev, value);
}

static inline byte
de620_get_register(struct net_device *dev, byte reg)
{
    byte value;

    de620_send_command(dev,reg);
    value = de620_read_byte(dev);
    de620_send_command(dev,W_DUMMY);

    return value;
}

/*********************************************************************
 *
 * Open/initialize the board.
 *
 * This routine should set everything up anew at each open, even
 * registers that "should" only need to be set once at boot, so that
 * there is a non-reboot way to recover if something goes wrong.
 *
 */
static int de620_open(struct net_device *dev)
{
    int ret = request_irq(dev->irq, de620_interrupt, 0, dev->name, dev);
    if (ret) {
        printk (KERN_ERR "%s: unable to get IRQ %d\n", dev->name, dev->irq);
        return ret;
    }

    if (adapter_init(dev)) {
        ret = -EIO;
        goto out_free_irq;
    }

    netif_start_queue(dev);
    return 0;

out_free_irq:
    free_irq(dev->irq, dev);
    return ret;
}

/************************************************
 *
 * The inverse routine to de620_open().
 *
 */

static int de620_close(struct net_device *dev)
{
    netif_stop_queue(dev);
    /* disable recv */
    de620_set_register(dev, W_TCR, RXOFF);
    free_irq(dev->irq, dev);
    return 0;
}

/*********************************************
 *
 * Set or clear the multicast filter for this adaptor.
 * (no real multicast implemented for the DE-620, but she can be promiscuous...)
 *
 */

static void de620_set_multicast_list(struct net_device *dev)
{
    if (!netdev_mc_empty(dev) || dev->flags&(IFF_ALLMULTI|IFF_PROMISC))
    { /* Enable promiscuous mode */
        de620_set_register(dev, W_TCR, (TCR_DEF & ~RXPBM) | RXALL);
    }
    else
    { /* Disable promiscuous mode, use normal mode */
        de620_set_register(dev, W_TCR, TCR_DEF);
    }
}

/*******************************************************
 *
 * Handle timeouts on transmit
 */

static void de620_timeout(struct net_device *dev)
{
    printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name, "network cable problem");
    /* Restart the adapter. */
    if (!adapter_init(dev)) /* maybe close it */
        netif_wake_queue(dev);
}

/*******************************************************
 *
 * Copy a buffer to the adapter transmit page memory.
 * Start sending.
 */
static int de620_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
    unsigned long flags;
    int len;
    byte *buffer = skb->data;
    byte using_txbuf;

    using_txbuf = de620_tx_buffs(dev); /* Peek at the adapter */

    netif_stop_queue(dev);


    if ((len = skb->len) < RUNT)
        len = RUNT;
    if (len & 1) /* send an even number of bytes */
        ++len;

    /* Start real output */

    spin_lock_irqsave(&de620_lock, flags);
    pr_debug("de620_start_xmit: len=%d, bufs 0x%02x\n",
        (int)skb->len, using_txbuf);

    /* select a free tx buffer. if there is one... */
    switch (using_txbuf) {
    default: /* both are free: use TXBF0 */
    case TXBF1: /* use TXBF0 */
        de620_send_command(dev,W_CR | RW0);
        using_txbuf |= TXBF0;
        break;

    case TXBF0: /* use TXBF1 */
        de620_send_command(dev,W_CR | RW1);
        using_txbuf |= TXBF1;
        break;

    case (TXBF0 | TXBF1): /* NONE!!! */
        printk(KERN_WARNING "%s: No tx-buffer available!\n", dev->name);
        spin_unlock_irqrestore(&de620_lock, flags);
        return NETDEV_TX_BUSY;
    }
    de620_write_block(dev, buffer, skb->len, len-skb->len);

    if(!(using_txbuf == (TXBF0 | TXBF1)))
        netif_wake_queue(dev);

    dev->stats.tx_packets++;
    spin_unlock_irqrestore(&de620_lock, flags);
    dev_kfree_skb (skb);
    return NETDEV_TX_OK;
}

/*****************************************************
 *
 * Handle the network interface interrupts.
 *
 */
static irqreturn_t
de620_interrupt(int irq_in, void *dev_id)
{
    struct net_device *dev = dev_id;
    byte irq_status;
    int bogus_count = 0;
    int again = 0;

    spin_lock(&de620_lock);

    /* Read the status register (_not_ the status port) */
    irq_status = de620_get_register(dev, R_STS);

    pr_debug("de620_interrupt (%2.2X)\n", irq_status);

    if (irq_status & RXGOOD) {
        do {
            again = de620_rx_intr(dev);
            pr_debug("again=%d\n", again);
        }
        while (again && (++bogus_count < 100));
    }

    if(de620_tx_buffs(dev) != (TXBF0 | TXBF1))
        netif_wake_queue(dev);

    spin_unlock(&de620_lock);
    return IRQ_HANDLED;
}

/**************************************
 *
 * Get a packet from the adapter
 *
 * Send it "upstairs"
 *
 */
static int de620_rx_intr(struct net_device *dev)
{
    struct header_buf {
        byte        status;
        byte        Rx_NextPage;
        unsigned short  Rx_ByteCount;
    } header_buf;
    struct sk_buff *skb;
    int size;
    byte *buffer;
    byte pagelink;
    byte curr_page;

    pr_debug("de620_rx_intr: next_rx_page = %d\n", next_rx_page);

    /* Tell the adapter that we are going to read data, and from where */
    de620_send_command(dev, W_CR | RRN);
    de620_set_register(dev, W_RSA1, next_rx_page);
    de620_set_register(dev, W_RSA0, 0);

    /* Deep breath, and away we goooooo */
    de620_read_block(dev, (byte *)&header_buf, sizeof(struct header_buf));
    pr_debug("page status=0x%02x, nextpage=%d, packetsize=%d\n",
        header_buf.status, header_buf.Rx_NextPage,
        header_buf.Rx_ByteCount);

    /* Plausible page header? */
    pagelink = header_buf.Rx_NextPage;
    if ((pagelink < first_rx_page) || (last_rx_page < pagelink)) {
        /* Ouch... Forget it! Skip all and start afresh... */
        printk(KERN_WARNING "%s: Ring overrun? Restoring...\n", dev->name);
        /* You win some, you lose some. And sometimes plenty... */
        adapter_init(dev);
        netif_wake_queue(dev);
        dev->stats.rx_over_errors++;
        return 0;
    }

    /* OK, this look good, so far. Let's see if it's consistent... */
    /* Let's compute the start of the next packet, based on where we are */
    pagelink = next_rx_page +
        ((header_buf.Rx_ByteCount + (4 - 1 + 0x100)) >> 8);

    /* Are we going to wrap around the page counter? */
    if (pagelink > last_rx_page)
        pagelink -= (last_rx_page - first_rx_page + 1);

    /* Is the _computed_ next page number equal to what the adapter says? */
    if (pagelink != header_buf.Rx_NextPage) {
        /* Naah, we'll skip this packet. Probably bogus data as well */
        printk(KERN_WARNING "%s: Page link out of sync! Restoring...\n", dev->name);
        next_rx_page = header_buf.Rx_NextPage; /* at least a try... */
        de620_send_command(dev, W_DUMMY);
        de620_set_register(dev, W_NPRF, next_rx_page);
        dev->stats.rx_over_errors++;
        return 0;
    }
    next_rx_page = pagelink;

    size = header_buf.Rx_ByteCount - 4;
    if ((size < RUNT) || (GIANT < size)) {
        printk(KERN_WARNING "%s: Illegal packet size: %d!\n", dev->name, size);
    }
    else { /* Good packet? */
        skb = netdev_alloc_skb(dev, size + 2);
        if (skb == NULL) { /* Yeah, but no place to put it... */
            printk(KERN_WARNING "%s: Couldn't allocate a sk_buff of size %d.\n", dev->name, size);
            dev->stats.rx_dropped++;
        }
        else { /* Yep! Go get it! */
            skb_reserve(skb,2); /* Align */
            /* skb->data points to the start of sk_buff data area */
            buffer = skb_put(skb,size);
            /* copy the packet into the buffer */
            de620_read_block(dev, buffer, size);
            pr_debug("Read %d bytes\n", size);
            skb->protocol=eth_type_trans(skb,dev);
            netif_rx(skb); /* deliver it "upstairs" */
            /* count all receives */
            dev->stats.rx_packets++;
            dev->stats.rx_bytes += size;
        }
    }

    /* Let's peek ahead to see if we have read the last current packet */
    /* NOTE! We're _not_ checking the 'EMPTY'-flag! This seems better... */
    curr_page = de620_get_register(dev, R_CPR);
    de620_set_register(dev, W_NPRF, next_rx_page);
    pr_debug("next_rx_page=%d CPR=%d\n", next_rx_page, curr_page);

    return next_rx_page != curr_page; /* That was slightly tricky... */
}

/*********************************************
 *
 * Reset the adapter to a known state
 *
 */
static int adapter_init(struct net_device *dev)
{
    int i;
    static int was_down;

    if ((nic_data.Model == 3) || (nic_data.Model == 0)) { /* CT */
        EIPRegister = NCTL0;
        if (nic_data.Media != 1)
            EIPRegister |= NIS0;    /* not BNC */
    }
    else if (nic_data.Model == 2) { /* UTP */
        EIPRegister = NCTL0 | NIS0;
    }

    if (utp)
        EIPRegister = NCTL0 | NIS0;
    if (bnc)
        EIPRegister = NCTL0;

    de620_send_command(dev, W_CR | RNOP | CLEAR);
    de620_send_command(dev, W_CR | RNOP);

    de620_set_register(dev, W_SCR, SCR_DEF);
    /* disable recv to wait init */
    de620_set_register(dev, W_TCR, RXOFF);

    /* Set the node ID in the adapter */
    for (i = 0; i < 6; ++i) { /* W_PARn = 0xaa + n */
        de620_set_register(dev, W_PAR0 + i, dev->dev_addr[i]);
    }

    de620_set_register(dev, W_EIP, EIPRegister);

    next_rx_page = first_rx_page = DE620_RX_START_PAGE;
    if (nic_data.RAM_Size)
        last_rx_page = nic_data.RAM_Size - 1;
    else /* 64k RAM */
        last_rx_page = 255;

    de620_set_register(dev, W_SPR, first_rx_page); /* Start Page Register*/
    de620_set_register(dev, W_EPR, last_rx_page);  /* End Page Register */
    de620_set_register(dev, W_CPR, first_rx_page);/*Current Page Register*/
    de620_send_command(dev, W_NPR | first_rx_page); /* Next Page Register*/
    de620_send_command(dev, W_DUMMY);
    de620_set_delay(dev);

    /* Final sanity check: Anybody out there? */
    /* Let's hope some bits from the statusregister make a good check */
#define CHECK_MASK (  0 | TXSUC |  T16  |  0  | RXCRC | RXSHORT |  0  |  0  )
#define CHECK_OK   (  0 |   0   |  0    |  0  |   0   |   0     |  0  |  0  )
        /* success:   X     0      0       X      0       0        X     X  */
        /* ignore:   EEDI                RXGOOD                   COLS  LNKS*/

    if (((i = de620_get_register(dev, R_STS)) & CHECK_MASK) != CHECK_OK) {
        printk(KERN_ERR "%s: Something has happened to the DE-620!  Please check it"
#ifdef SHUTDOWN_WHEN_LOST
            " and do a new ifconfig"
#endif
            "! (%02x)\n", dev->name, i);
#ifdef SHUTDOWN_WHEN_LOST
        /* Goodbye, cruel world... */
        dev->flags &= ~IFF_UP;
        de620_close(dev);
#endif
        was_down = 1;
        return 1; /* failed */
    }
    if (was_down) {
        printk(KERN_WARNING "%s: Thanks, I feel much better now!\n", dev->name);
        was_down = 0;
    }

    /* All OK, go ahead... */
    de620_set_register(dev, W_TCR, TCR_DEF);

    return 0; /* all ok */
}

static const struct net_device_ops de620_netdev_ops = {
    .ndo_open       = de620_open,
    .ndo_stop       = de620_close,
    .ndo_start_xmit     = de620_start_xmit,
    .ndo_tx_timeout     = de620_timeout,
    .ndo_set_rx_mode    = de620_set_multicast_list,
    .ndo_change_mtu     = eth_change_mtu,
    .ndo_set_mac_address    = eth_mac_addr,
    .ndo_validate_addr  = eth_validate_addr,
};

/******************************************************************************
 *
 * Only start-up code below
 *
 */
/****************************************
 *
 * Check if there is a DE-620 connected
 */
struct net_device * __init de620_probe(int unit)
{
    byte checkbyte = 0xa5;
    struct net_device *dev;
    int err = -ENOMEM;
    int i;

    dev = alloc_etherdev(0);
    if (!dev)
        goto out;

    spin_lock_init(&de620_lock);

    /*
     * This is where the base_addr and irq gets set.
     * Tunable at compile-time and insmod-time
     */
    dev->base_addr = io;
    dev->irq       = irq;

    /* allow overriding parameters on command line */
    if (unit >= 0) {
        sprintf(dev->name, "eth%d", unit);
        netdev_boot_setup_check(dev);
    }

    pr_debug("%s", version);

    printk(KERN_INFO "D-Link DE-620 pocket adapter");

    if (!request_region(dev->base_addr, 3, "de620")) {
        printk(" io 0x%3lX, which is busy.\n", dev->base_addr);
        err = -EBUSY;
        goto out1;
    }

    /* Initially, configure basic nibble mode, so we can read the EEPROM */
    NIC_Cmd = DEF_NIC_CMD;
    de620_set_register(dev, W_EIP, EIPRegister);

    /* Anybody out there? */
    de620_set_register(dev, W_CPR, checkbyte);
    checkbyte = de620_get_register(dev, R_CPR);

    if ((checkbyte != 0xa5) || (read_eeprom(dev) != 0)) {
        printk(" not identified in the printer port\n");
        err = -ENODEV;
        goto out2;
    }

    /* else, got it! */
    dev->dev_addr[0] = nic_data.NodeID[0];
    for (i = 1; i < ETH_ALEN; i++) {
        dev->dev_addr[i] = nic_data.NodeID[i];
        dev->broadcast[i] = 0xff;
    }

    printk(", Ethernet Address: %pM", dev->dev_addr);

    printk(" (%dk RAM,",
        (nic_data.RAM_Size) ? (nic_data.RAM_Size >> 2) : 64);

    if (nic_data.Media == 1)
        printk(" BNC)\n");
    else
        printk(" UTP)\n");

    dev->netdev_ops = &de620_netdev_ops;
    dev->watchdog_timeo = HZ*2;

    /* base_addr and irq are already set, see above! */

    /* dump eeprom */
    pr_debug("\nEEPROM contents:\n"
        "RAM_Size = 0x%02X\n"
        "NodeID = %pM\n"
        "Model = %d\n"
        "Media = %d\n"
        "SCR = 0x%02x\n", nic_data.RAM_Size, nic_data.NodeID,
        nic_data.Model, nic_data.Media, nic_data.SCR);

    err = register_netdev(dev);
    if (err)
        goto out2;
    return dev;

out2:
    release_region(dev->base_addr, 3);
out1:
    free_netdev(dev);
out:
    return ERR_PTR(err);
}

/**********************************
 *
 * Read info from on-board EEPROM
 *
 * Note: Bitwise serial I/O to/from the EEPROM vi the status _register_!
 */
#define sendit(dev,data) de620_set_register(dev, W_EIP, data | EIPRegister);

static unsigned short __init ReadAWord(struct net_device *dev, int from)
{
    unsigned short data;
    int nbits;

    /* cs   [__~~] SET SEND STATE */
    /* di   [____]                */
    /* sck  [_~~_]                */
    sendit(dev, 0); sendit(dev, 1); sendit(dev, 5); sendit(dev, 4);

    /* Send the 9-bit address from where we want to read the 16-bit word */
    for (nbits = 9; nbits > 0; --nbits, from <<= 1) {
        if (from & 0x0100) { /* bit set? */
            /* cs    [~~~~] SEND 1 */
            /* di    [~~~~]        */
            /* sck   [_~~_]        */
            sendit(dev, 6); sendit(dev, 7); sendit(dev, 7); sendit(dev, 6);
        }
        else {
            /* cs    [~~~~] SEND 0 */
            /* di    [____]        */
            /* sck   [_~~_]        */
            sendit(dev, 4); sendit(dev, 5); sendit(dev, 5); sendit(dev, 4);
        }
    }

    /* Shift in the 16-bit word. The bits appear serially in EEDI (=0x80) */
    for (data = 0, nbits = 16; nbits > 0; --nbits) {
        /* cs    [~~~~] SEND 0 */
        /* di    [____]        */
        /* sck   [_~~_]        */
        sendit(dev, 4); sendit(dev, 5); sendit(dev, 5); sendit(dev, 4);
        data = (data << 1) | ((de620_get_register(dev, R_STS) & EEDI) >> 7);
    }
    /* cs    [____] RESET SEND STATE */
    /* di    [____]                  */
    /* sck   [_~~_]                  */
    sendit(dev, 0); sendit(dev, 1); sendit(dev, 1); sendit(dev, 0);

    return data;
}

static int __init read_eeprom(struct net_device *dev)
{
    unsigned short wrd;

    /* D-Link Ethernet addresses are in the series  00:80:c8:7X:XX:XX:XX */
    wrd = ReadAWord(dev, 0x1aa);    /* bytes 0 + 1 of NodeID */
    if (!clone && (wrd != htons(0x0080))) /* Valid D-Link ether sequence? */
        return -1; /* Nope, not a DE-620 */
    nic_data.NodeID[0] = wrd & 0xff;
    nic_data.NodeID[1] = wrd >> 8;

    wrd = ReadAWord(dev, 0x1ab);    /* bytes 2 + 3 of NodeID */
    if (!clone && ((wrd & 0xff) != 0xc8)) /* Valid D-Link ether sequence? */
        return -1; /* Nope, not a DE-620 */
    nic_data.NodeID[2] = wrd & 0xff;
    nic_data.NodeID[3] = wrd >> 8;

    wrd = ReadAWord(dev, 0x1ac);    /* bytes 4 + 5 of NodeID */
    nic_data.NodeID[4] = wrd & 0xff;
    nic_data.NodeID[5] = wrd >> 8;

    wrd = ReadAWord(dev, 0x1ad);    /* RAM size in pages (256 bytes). 0 = 64k */
    nic_data.RAM_Size = (wrd >> 8);

    wrd = ReadAWord(dev, 0x1ae);    /* hardware model (CT = 3) */
    nic_data.Model = (wrd & 0xff);

    wrd = ReadAWord(dev, 0x1af); /* media (indicates BNC/UTP) */
    nic_data.Media = (wrd & 0xff);

    wrd = ReadAWord(dev, 0x1a8); /* System Configuration Register */
    nic_data.SCR = (wrd >> 8);

    return 0; /* no errors */
}

/******************************************************************************
 *
 * Loadable module skeleton
 *
 */
#ifdef MODULE
static struct net_device *de620_dev;

int __init init_module(void)
{
    de620_dev = de620_probe(-1);
    if (IS_ERR(de620_dev))
        return PTR_ERR(de620_dev);
    return 0;
}

void cleanup_module(void)
{
    unregister_netdev(de620_dev);
    release_region(de620_dev->base_addr, 3);
    free_netdev(de620_dev);
}
#endif /* MODULE */
MODULE_LICENSE("GPL");