/*------------------------------------------------------------------------
 * lan91c96.c
 * This is a driver for SMSC's LAN91C96 single-chip Ethernet device, based
 * on the SMC91111 driver from U-boot.
 *
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Rolf Offermanns <rof@sysgo.de>
 *
 * Copyright (C) 2001 Standard Microsystems Corporation (SMSC)
 *       Developed by Simple Network Magic Corporation (SNMC)
 * Copyright (C) 1996 by Erik Stahlman (ES)
 *
 * 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 of the License, 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Information contained in this file was obtained from the LAN91C96
 * manual from SMC.  To get a copy, if you really want one, you can find
 * information under www.smsc.com.
 *
 *
 * "Features" of the SMC chip:
 *   6144 byte packet memory. ( for the 91C96 )
 *   EEPROM for configuration
 *   AUI/TP selection  ( mine has 10Base2/10BaseT select )
 *
 * Arguments:
 *      io      = for the base address
 *      irq     = for the IRQ
 *
 * author:
 *      Erik Stahlman                           ( erik@vt.edu )
 *      Daris A Nevil                           ( dnevil@snmc.com )
 *
 *
 * Hardware multicast code from Peter Cammaert ( pc@denkart.be )
 *
 * Sources:
 *    o   SMSC LAN91C96 databook (www.smsc.com)
 *    o   smc91111.c (u-boot driver)
 *    o   smc9194.c (linux kernel driver)
 *    o   lan91c96.c (Intel Diagnostic Manager driver)
 *
 * History:
 *      04/30/03  Mathijs Haarman       Modified smc91111.c (u-boot version)
 *                                      for lan91c96
 *---------------------------------------------------------------------------
 */

#include <common.h>
#include <command.h>
#include <malloc.h>
#include "lan91c96.h"
#include <net.h>
#include <linux/compiler.h>

/*------------------------------------------------------------------------
 *
 * Configuration options, for the experienced user to change.
 *
 -------------------------------------------------------------------------*/

/* Use power-down feature of the chip */
#define POWER_DOWN      0

/*
 * Wait time for memory to be free.  This probably shouldn't be
 * tuned that much, as waiting for this means nothing else happens
 * in the system
*/
#define MEMORY_WAIT_TIME 16

#define SMC_DEBUG 0

#if (SMC_DEBUG > 2 )
#define PRINTK3(args...) printf(args)
#else
#define PRINTK3(args...)
#endif

#if SMC_DEBUG > 1
#define PRINTK2(args...) printf(args)
#else
#define PRINTK2(args...)
#endif

#ifdef SMC_DEBUG
#define PRINTK(args...) printf(args)
#else
#define PRINTK(args...)
#endif


/*------------------------------------------------------------------------
 *
 * The internal workings of the driver.  If you are changing anything
 * here with the SMC stuff, you should have the datasheet and know
 * what you are doing.
 *
 *------------------------------------------------------------------------
 */
#define DRIVER_NAME "LAN91C96"
#define SMC_ALLOC_MAX_TRY 5
#define SMC_TX_TIMEOUT 30

#define ETH_ZLEN 60

#ifdef  CONFIG_LAN91C96_USE_32_BIT
#define USE_32_BIT  1
#else
#undef USE_32_BIT
#endif

/* See if a MAC address is defined in the current environment. If so use it. If not
 . print a warning and set the environment and other globals with the default.
 . If an EEPROM is present it really should be consulted.
*/
static int smc_get_ethaddr(bd_t *bd, struct eth_device *dev);
static int get_rom_mac(struct eth_device *dev, unsigned char *v_rom_mac);

/* ------------------------------------------------------------
 * Internal routines
 * ------------------------------------------------------------
 */

static unsigned char smc_mac_addr[] = { 0xc0, 0x00, 0x00, 0x1b, 0x62, 0x9c };

/*
 * This function must be called before smc_open() if you want to override
 * the default mac address.
 */

static void smc_set_mac_addr(const unsigned char *addr)
{
        int i;

        for (i = 0; i < sizeof (smc_mac_addr); i++) {
                smc_mac_addr[i] = addr[i];
        }
}

/***********************************************
 * Show available memory                       *
 ***********************************************/
void dump_memory_info(struct eth_device *dev)
{
        __maybe_unused word mem_info;
        word old_bank;

        old_bank = SMC_inw(dev, LAN91C96_BANK_SELECT) & 0xF;

        SMC_SELECT_BANK(dev, 0);
        mem_info = SMC_inw(dev, LAN91C96_MIR);
        PRINTK2 ("Memory: %4d available\n", (mem_info >> 8) * 2048);

        SMC_SELECT_BANK(dev, old_bank);
}

/*
 * A rather simple routine to print out a packet for debugging purposes.
 */
#if SMC_DEBUG > 2
static void print_packet (byte *, int);
#endif

static int poll4int (struct eth_device *dev, byte mask, int timeout)
{
        int tmo = get_timer (0) + timeout * CONFIG_SYS_HZ;
        int is_timeout = 0;
        word old_bank = SMC_inw(dev, LAN91C96_BANK_SELECT);

        PRINTK2 ("Polling...\n");
        SMC_SELECT_BANK(dev, 2);
        while ((SMC_inw(dev, LAN91C96_INT_STATS) & mask) == 0) {
                if (get_timer (0) >= tmo) {
                        is_timeout = 1;
                        break;
                }
        }

        /* restore old bank selection */
        SMC_SELECT_BANK(dev, old_bank);

        if (is_timeout)
                return 1;
        else
                return 0;
}

/*
 * Function: smc_reset
 * Purpose:
 *      This sets the SMC91111 chip to its normal state, hopefully from whatever
 *      mess that any other DOS driver has put it in.
 *
 * Maybe I should reset more registers to defaults in here?  SOFTRST  should
 * do that for me.
 *
 * Method:
 *      1.  send a SOFT RESET
 *      2.  wait for it to finish
 *      3.  enable autorelease mode
 *      4.  reset the memory management unit
 *      5.  clear all interrupts
 *
*/
static void smc_reset(struct eth_device *dev)
{
        PRINTK2("%s:smc_reset\n", dev->name);

        /* This resets the registers mostly to defaults, but doesn't
           affect EEPROM.  That seems unnecessary */
        SMC_SELECT_BANK(dev, 0);
        SMC_outw(dev, LAN91C96_RCR_SOFT_RST, LAN91C96_RCR);

        udelay (10);

        /* Disable transmit and receive functionality */
        SMC_outw(dev, 0, LAN91C96_RCR);
        SMC_outw(dev, 0, LAN91C96_TCR);

        /* set the control register */
        SMC_SELECT_BANK(dev, 1);
        SMC_outw(dev, SMC_inw(dev, LAN91C96_CONTROL) | LAN91C96_CTR_BIT_8,
                          LAN91C96_CONTROL);

        /* Disable all interrupts */
        SMC_outb(dev, 0, LAN91C96_INT_MASK);
}

/*
 * Function: smc_enable
 * Purpose: let the chip talk to the outside work
 * Method:
 *      1.  Initialize the Memory Configuration Register
 *      2.  Enable the transmitter
 *      3.  Enable the receiver
*/
static void smc_enable(struct eth_device *dev)
{
        PRINTK2("%s:smc_enable\n", dev->name);
        SMC_SELECT_BANK(dev, 0);

        /* Initialize the Memory Configuration Register. See page
           49 of the LAN91C96 data sheet for details. */
        SMC_outw(dev, LAN91C96_MCR_TRANSMIT_PAGES, LAN91C96_MCR);

        /* Initialize the Transmit Control Register */
        SMC_outw(dev, LAN91C96_TCR_TXENA, LAN91C96_TCR);
        /* Initialize the Receive Control Register
         * FIXME:
         * The promiscuous bit set because I could not receive ARP reply
         * packets from the server when I send a ARP request. It only works
         * when I set the promiscuous bit
         */
        SMC_outw(dev, LAN91C96_RCR_RXEN | LAN91C96_RCR_PRMS, LAN91C96_RCR);
}

/*
 * Function: smc_shutdown
 * Purpose:  closes down the SMC91xxx chip.
 * Method:
 *      1. zero the interrupt mask
 *      2. clear the enable receive flag
 *      3. clear the enable xmit flags
 *
 * TODO:
 *   (1) maybe utilize power down mode.
 *      Why not yet?  Because while the chip will go into power down mode,
 *      the manual says that it will wake up in response to any I/O requests
 *      in the register space.   Empirical results do not show this working.
 */
static void smc_shutdown(struct eth_device *dev)
{
        PRINTK2("%s:smc_shutdown\n", dev->name);

        /* no more interrupts for me */
        SMC_SELECT_BANK(dev, 2);
        SMC_outb(dev, 0, LAN91C96_INT_MASK);

        /* and tell the card to stay away from that nasty outside world */
        SMC_SELECT_BANK(dev, 0);
        SMC_outb(dev, 0, LAN91C96_RCR);
        SMC_outb(dev, 0, LAN91C96_TCR);
}


/*
 * Function:  smc_hardware_send_packet(struct net_device * )
 * Purpose:
 *      This sends the actual packet to the SMC9xxx chip.
 *
 * Algorithm:
 *      First, see if a saved_skb is available.
 *              ( this should NOT be called if there is no 'saved_skb'
 *      Now, find the packet number that the chip allocated
 *      Point the data pointers at it in memory
 *      Set the length word in the chip's memory
 *      Dump the packet to chip memory
 *      Check if a last byte is needed ( odd length packet )
 *              if so, set the control flag right
 *      Tell the card to send it
 *      Enable the transmit interrupt, so I know if it failed
 *      Free the kernel data if I actually sent it.
 */
static int smc_send_packet(struct eth_device *dev, void *packet,
                int packet_length)
{
        byte packet_no;
        byte *buf;
        int length;
        int numPages;
        int try = 0;
        int time_out;
        byte status;


        PRINTK3("%s:smc_hardware_send_packet\n", dev->name);

        length = ETH_ZLEN < packet_length ? packet_length : ETH_ZLEN;

        /* allocate memory
         ** The MMU wants the number of pages to be the number of 256 bytes
         ** 'pages', minus 1 ( since a packet can't ever have 0 pages :) )
         **
         ** The 91C111 ignores the size bits, but the code is left intact
         ** for backwards and future compatibility.
         **
         ** Pkt size for allocating is data length +6 (for additional status
         ** words, length and ctl!)
         **
         ** If odd size then last byte is included in this header.
         */
        numPages = ((length & 0xfffe) + 6);
        numPages >>= 8;                         /* Divide by 256 */

        if (numPages > 7) {
                printf("%s: Far too big packet error. \n", dev->name);
                return 0;
        }

        /* now, try to allocate the memory */

        SMC_SELECT_BANK(dev, 2);
        SMC_outw(dev, LAN91C96_MMUCR_ALLOC_TX | numPages, LAN91C96_MMU);

  again:
        try++;
        time_out = MEMORY_WAIT_TIME;
        do {
                status = SMC_inb(dev, LAN91C96_INT_STATS);
                if (status & LAN91C96_IST_ALLOC_INT) {

                        SMC_outb(dev, LAN91C96_IST_ALLOC_INT,
                                        LAN91C96_INT_STATS);
                        break;
                }
        } while (--time_out);

        if (!time_out) {
                PRINTK2 ("%s: memory allocation, try %d failed ...\n",
                                 dev->name, try);
                if (try < SMC_ALLOC_MAX_TRY)
                        goto again;
                else
                        return 0;
        }

        PRINTK2 ("%s: memory allocation, try %d succeeded ...\n",
                         dev->name, try);

        /* I can send the packet now.. */
        buf = (byte *) packet;

        /* If I get here, I _know_ there is a packet slot waiting for me */
        packet_no = SMC_inb(dev, LAN91C96_ARR);
        if (packet_no & LAN91C96_ARR_FAILED) {
                /* or isn't there?  BAD CHIP! */
                printf("%s: Memory allocation failed. \n", dev->name);
                return 0;
        }

        /* we have a packet address, so tell the card to use it */
        SMC_outb(dev, packet_no, LAN91C96_PNR);

        /* point to the beginning of the packet */
        SMC_outw(dev, LAN91C96_PTR_AUTO_INCR, LAN91C96_POINTER);

        PRINTK3("%s: Trying to xmit packet of length %x\n",
                         dev->name, length);

#if SMC_DEBUG > 2
        printf ("Transmitting Packet\n");
        print_packet (buf, length);
#endif

        /* send the packet length ( +6 for status, length and ctl byte )
           and the status word ( set to zeros ) */
#ifdef USE_32_BIT
        SMC_outl(dev, (length + 6) << 16, LAN91C96_DATA_HIGH);
#else
        SMC_outw(dev, 0, LAN91C96_DATA_HIGH);
        /* send the packet length ( +6 for status words, length, and ctl */
        SMC_outw(dev, (length + 6), LAN91C96_DATA_HIGH);
#endif /* USE_32_BIT */

        /* send the actual data
         * I _think_ it's faster to send the longs first, and then
         * mop up by sending the last word.  It depends heavily
         * on alignment, at least on the 486.  Maybe it would be
         * a good idea to check which is optimal?  But that could take
         * almost as much time as is saved?
         */
#ifdef USE_32_BIT
        SMC_outsl(dev, LAN91C96_DATA_HIGH, buf, length >> 2);
        if (length & 0x2)
                SMC_outw(dev, *((word *) (buf + (length & 0xFFFFFFFC))),
                                  LAN91C96_DATA_HIGH);
#else
        SMC_outsw(dev, LAN91C96_DATA_HIGH, buf, (length) >> 1);
#endif /* USE_32_BIT */

        /* Send the last byte, if there is one.   */
        if ((length & 1) == 0) {
                SMC_outw(dev, 0, LAN91C96_DATA_HIGH);
        } else {
                SMC_outw(dev, buf[length - 1] | 0x2000, LAN91C96_DATA_HIGH);
        }

        /* and let the chipset deal with it */
        SMC_outw(dev, LAN91C96_MMUCR_ENQUEUE, LAN91C96_MMU);

        /* poll for TX INT */
        if (poll4int (dev, LAN91C96_MSK_TX_INT, SMC_TX_TIMEOUT)) {
                /* sending failed */
                PRINTK2("%s: TX timeout, sending failed...\n", dev->name);

                /* release packet */
                SMC_outw(dev, LAN91C96_MMUCR_RELEASE_TX, LAN91C96_MMU);

                /* wait for MMU getting ready (low) */
                while (SMC_inw(dev, LAN91C96_MMU) & LAN91C96_MMUCR_NO_BUSY)
                        udelay (10);

                PRINTK2("MMU ready\n");


                return 0;
        } else {
                /* ack. int */
                SMC_outw(dev, LAN91C96_IST_TX_INT, LAN91C96_INT_STATS);

                PRINTK2("%s: Sent packet of length %d \n", dev->name, length);

                /* release packet */
                SMC_outw(dev, LAN91C96_MMUCR_RELEASE_TX, LAN91C96_MMU);

                /* wait for MMU getting ready (low) */
                while (SMC_inw(dev, LAN91C96_MMU) & LAN91C96_MMUCR_NO_BUSY)
                        udelay (10);

                PRINTK2 ("MMU ready\n");
        }

        return length;
}


/*
 * Open and Initialize the board
 *
 * Set up everything, reset the card, etc ..
 *
 */
static int smc_open(bd_t *bd, struct eth_device *dev)
{
        int i, err;                     /* used to set hw ethernet address */

        PRINTK2("%s:smc_open\n", dev->name);

        /* reset the hardware */

        smc_reset(dev);
        smc_enable(dev);

        SMC_SELECT_BANK(dev, 1);
        /* set smc_mac_addr, and sync it with u-boot globals */
        err = smc_get_ethaddr(bd, dev);
        if (err < 0)
                return -1;
#ifdef USE_32_BIT
        for (i = 0; i < 6; i += 2) {
                word address;

                address = smc_mac_addr[i + 1] << 8;
                address |= smc_mac_addr[i];
                SMC_outw(dev, address, LAN91C96_IA0 + i);
        }
#else
        for (i = 0; i < 6; i++)
                SMC_outb(dev, smc_mac_addr[i], LAN91C96_IA0 + i);
#endif
        return 0;
}

/*-------------------------------------------------------------
 *
 * smc_rcv -  receive a packet from the card
 *
 * There is ( at least ) a packet waiting to be read from
 * chip-memory.
 *
 * o Read the status
 * o If an error, record it
 * o otherwise, read in the packet
 *-------------------------------------------------------------
 */
static int smc_rcv(struct eth_device *dev)
{
        int packet_number;
        word status;
        word packet_length;
        int is_error = 0;

#ifdef USE_32_BIT
        dword stat_len;
#endif


        SMC_SELECT_BANK(dev, 2);
        packet_number = SMC_inw(dev, LAN91C96_FIFO);

        if (packet_number & LAN91C96_FIFO_RXEMPTY) {
                return 0;
        }

        PRINTK3("%s:smc_rcv\n", dev->name);
        /*  start reading from the start of the packet */
        SMC_outw(dev, LAN91C96_PTR_READ | LAN91C96_PTR_RCV |
                          LAN91C96_PTR_AUTO_INCR, LAN91C96_POINTER);

        /* First two words are status and packet_length */
#ifdef USE_32_BIT
        stat_len = SMC_inl(dev, LAN91C96_DATA_HIGH);
        status = stat_len & 0xffff;
        packet_length = stat_len >> 16;
#else
        status = SMC_inw(dev, LAN91C96_DATA_HIGH);
        packet_length = SMC_inw(dev, LAN91C96_DATA_HIGH);
#endif

        packet_length &= 0x07ff;        /* mask off top bits */

        PRINTK2 ("RCV: STATUS %4x LENGTH %4x\n", status, packet_length);

        if (!(status & FRAME_FILTER)) {
                /* Adjust for having already read the first two words */
                packet_length -= 4;             /*4; */


                /* set odd length for bug in LAN91C111, */
                /* which never sets RS_ODDFRAME */
                /* TODO ? */


#ifdef USE_32_BIT
                PRINTK3 (" Reading %d dwords (and %d bytes) \n",
                         packet_length >> 2, packet_length & 3);
                /* QUESTION:  Like in the TX routine, do I want
                   to send the DWORDs or the bytes first, or some
                   mixture.  A mixture might improve already slow PIO
                   performance  */
                SMC_insl(dev, LAN91C96_DATA_HIGH, NetRxPackets[0],
                                packet_length >> 2);
                /* read the left over bytes */
                if (packet_length & 3) {
                        int i;

                        byte *tail = (byte *) (NetRxPackets[0] + (packet_length & ~3));
                        dword leftover = SMC_inl(dev, LAN91C96_DATA_HIGH);

                        for (i = 0; i < (packet_length & 3); i++)
                                *tail++ = (byte) (leftover >> (8 * i)) & 0xff;
                }
#else
                PRINTK3 (" Reading %d words and %d byte(s) \n",
                                 (packet_length >> 1), packet_length & 1);
                SMC_insw(dev, LAN91C96_DATA_HIGH, NetRxPackets[0],
                                packet_length >> 1);

#endif /* USE_32_BIT */

#if     SMC_DEBUG > 2
                printf ("Receiving Packet\n");
                print_packet((byte *)NetRxPackets[0], packet_length);
#endif
        } else {
                /* error ... */
                /* TODO ? */
                is_error = 1;
        }

        while (SMC_inw(dev, LAN91C96_MMU) & LAN91C96_MMUCR_NO_BUSY)
                udelay (1);             /* Wait until not busy */

        /*  error or good, tell the card to get rid of this packet */
        SMC_outw(dev, LAN91C96_MMUCR_RELEASE_RX, LAN91C96_MMU);

        while (SMC_inw(dev, LAN91C96_MMU) & LAN91C96_MMUCR_NO_BUSY)
                udelay (1);             /* Wait until not busy */

        if (!is_error) {
                /* Pass the packet up to the protocol layers. */
                NetReceive (NetRxPackets[0], packet_length);
                return packet_length;
        } else {
                return 0;
        }

}

/*----------------------------------------------------
 * smc_close
 *
 * this makes the board clean up everything that it can
 * and not talk to the outside world.   Caused by
 * an 'ifconfig ethX down'
 *
 -----------------------------------------------------*/
static int smc_close(struct eth_device *dev)
{
        PRINTK2("%s:smc_close\n", dev->name);

        /* clear everything */
        smc_shutdown(dev);

        return 0;
}

#if SMC_DEBUG > 2
static void print_packet(byte *buf, int length)
{
#if 0
        int i;
        int remainder;
        int lines;

        printf ("Packet of length %d \n", length);

        lines = length / 16;
        remainder = length % 16;

        for (i = 0; i < lines; i++) {
                int cur;

                for (cur = 0; cur < 8; cur++) {
                        byte a, b;

                        a = *(buf++);
                        b = *(buf++);
                        printf ("%02x%02x ", a, b);
                }
                printf ("\n");
        }
        for (i = 0; i < remainder / 2; i++) {
                byte a, b;

                a = *(buf++);
                b = *(buf++);
                printf ("%02x%02x ", a, b);
        }
        printf ("\n");
#endif /* 0 */
}
#endif /* SMC_DEBUG > 2 */

static int  lan91c96_init(struct eth_device *dev, bd_t *bd)
{
        return smc_open(bd, dev);
}

static void lan91c96_halt(struct eth_device *dev)
{
        smc_close(dev);
}

static int lan91c96_recv(struct eth_device *dev)
{
        return smc_rcv(dev);
}

static int lan91c96_send(struct eth_device *dev, void *packet,
                int length)
{
        return smc_send_packet(dev, packet, length);
}

/* smc_get_ethaddr
 *
 * This checks both the environment and the ROM for an ethernet address. If
 * found, the environment takes precedence.
 */

static int smc_get_ethaddr(bd_t *bd, struct eth_device *dev)
{
        uchar v_mac[6];

        if (!eth_getenv_enetaddr("ethaddr", v_mac)) {
                /* get ROM mac value if any */
                if (!get_rom_mac(dev, v_mac)) {
                        printf("\n*** ERROR: ethaddr is NOT set !!\n");
                        return -1;
                }
                eth_setenv_enetaddr("ethaddr", v_mac);
        }

        smc_set_mac_addr(v_mac); /* use old function to update smc default */
        PRINTK("Using MAC Address %pM\n", v_mac);
        return 0;
}

/*
 * get_rom_mac()
 * Note, this has omly been tested for the OMAP730 P2.
 */

static int get_rom_mac(struct eth_device *dev, unsigned char *v_rom_mac)
{
#ifdef HARDCODE_MAC     /* used for testing or to supress run time warnings */
        char hw_mac_addr[] = { 0x02, 0x80, 0xad, 0x20, 0x31, 0xb8 };

        memcpy (v_rom_mac, hw_mac_addr, 6);
        return (1);
#else
        int i;
        SMC_SELECT_BANK(dev, 1);
        for (i=0; i<6; i++)
        {
                v_rom_mac[i] = SMC_inb(dev, LAN91C96_IA0 + i);
        }
        return (1);
#endif
}

/* Structure to detect the device IDs */
struct id_type {
        u8 id;
        char *name;
};
static struct id_type supported_chips[] = {
        {0, ""}, /* Dummy entry to prevent id check failure */
        {9, "LAN91C110"},
        {8, "LAN91C100FD"},
        {7, "LAN91C100"},
        {5, "LAN91C95"},
        {4, "LAN91C94/96"},
        {3, "LAN91C90/92"},
};
/* lan91c96_detect_chip
 * See:
 * http://www.embeddedsys.com/subpages/resources/images/documents/LAN91C96_datasheet.pdf
 * page 71 - that is the closest we get to detect this device
 */
static int lan91c96_detect_chip(struct eth_device *dev)
{
        u8 chip_id;
        int r;
        SMC_SELECT_BANK(dev, 3);
        chip_id = (SMC_inw(dev, 0xA) & LAN91C96_REV_CHIPID) >> 4;
        SMC_SELECT_BANK(dev, 0);
        for (r = 0; r < sizeof(supported_chips) / sizeof(struct id_type); r++)
                if (chip_id == supported_chips[r].id)
                        return r;
        return 0;
}

int lan91c96_initialize(u8 dev_num, int base_addr)
{
        struct eth_device *dev;
        int r = 0;

        dev = malloc(sizeof(*dev));
        if (!dev) {
                return 0;
        }
        memset(dev, 0, sizeof(*dev));

        dev->iobase = base_addr;

        /* Try to detect chip. Will fail if not present. */
        r = lan91c96_detect_chip(dev);
        if (!r) {
                free(dev);
                return 0;
        }
        get_rom_mac(dev, dev->enetaddr);

        dev->init = lan91c96_init;
        dev->halt = lan91c96_halt;
        dev->send = lan91c96_send;
        dev->recv = lan91c96_recv;
        sprintf(dev->name, "%s-%hu", supported_chips[r].name, dev_num);

        eth_register(dev);
        return 0;
}