/*------------------------------------------------------------------------
 . smc9194.c
 . This is a driver for SMC's 9000 series of Ethernet cards.
 .
 . Copyright (C) 1996 by Erik Stahlman
 . This software may be used and distributed according to the terms
 . of the GNU General Public License, incorporated herein by reference.
 .
 . "Features" of the SMC chip:
 .   4608 byte packet memory. ( for the 91C92.  Others have more )
 .   EEPROM for configuration
 .   AUI/TP selection  ( mine has 10Base2/10BaseT select )
 .
 . Arguments:
 .      io               = for the base address
 .      irq      = for the IRQ
 .      ifport = 0 for autodetect, 1 for TP, 2 for AUI ( or 10base2 )
 .
 . author:
 .      Erik Stahlman                           ( erik@vt.edu )
 . contributors:
 .      Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 .
 . Hardware multicast code from Peter Cammaert ( pc@denkart.be )
 .
 . Sources:
 .    o   SMC databook
 .    o   skeleton.c by Donald Becker ( becker@scyld.com )
 .    o   ( a LOT of advice from Becker as well )
 .
 . History:
 .      12/07/95  Erik Stahlman  written, got receive/xmit handled
 .      01/03/96  Erik Stahlman  worked out some bugs, actually usable!!! :-)
 .      01/06/96  Erik Stahlman  cleaned up some, better testing, etc
 .      01/29/96  Erik Stahlman  fixed autoirq, added multicast
 .      02/01/96  Erik Stahlman  1. disabled all interrupts in smc_reset
 .                               2. got rid of post-decrementing bug -- UGH.
 .      02/13/96  Erik Stahlman  Tried to fix autoirq failure.  Added more
 .                               descriptive error messages.
 .      02/15/96  Erik Stahlman  Fixed typo that caused detection failure
 .      02/23/96  Erik Stahlman  Modified it to fit into kernel tree
 .                               Added support to change hardware address
 .                               Cleared stats on opens
 .      02/26/96  Erik Stahlman  Trial support for Kernel 1.2.13
 .                               Kludge for automatic IRQ detection
 .      03/04/96  Erik Stahlman  Fixed kernel 1.3.70 +
 .                               Fixed bug reported by Gardner Buchanan in
 .                                 smc_enable, with outw instead of outb
 .      03/06/96  Erik Stahlman  Added hardware multicast from Peter Cammaert
 .      04/14/00  Heiko Pruessing (SMA Regelsysteme)  Fixed bug in chip memory
 .                               allocation
 .      08/20/00  Arnaldo Melo   fix kfree(skb) in smc_hardware_send_packet
 .      12/15/00  Christian Jullien fix "Warning: kfree_skb on hard IRQ"
 .      11/08/01 Matt Domsch     Use common crc32 function
 ----------------------------------------------------------------------------*/

static const char version[] =
        "smc9194.c:v0.14 12/15/00 by Erik Stahlman (erik@vt.edu)";

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/crc32.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/bitops.h>

#include <asm/io.h>

#include "smc9194.h"

#define DRV_NAME "smc9194"

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

/*
 . Do you want to use 32 bit xfers?  This should work on all chips, as
 . the chipset is designed to accommodate them.
*/
#ifdef __sh__
#undef USE_32_BIT
#else
#define USE_32_BIT 1
#endif

/*
 .the SMC9194 can be at any of the following port addresses.  To change,
 .for a slightly different card, you can add it to the array.  Keep in
 .mind that the array must end in zero.
*/

struct devlist {
        unsigned int port;
        unsigned int irq;
};

static struct devlist smc_devlist[] __initdata = {
        {.port = 0x200, .irq = 0},
        {.port = 0x220, .irq = 0},
        {.port = 0x240, .irq = 0},
        {.port = 0x260, .irq = 0},
        {.port = 0x280, .irq = 0},
        {.port = 0x2A0, .irq = 0},
        {.port = 0x2C0, .irq = 0},
        {.port = 0x2E0, .irq = 0},
        {.port = 0x300, .irq = 0},
        {.port = 0x320, .irq = 0},
        {.port = 0x340, .irq = 0},
        {.port = 0x360, .irq = 0},
        {.port = 0x380, .irq = 0},
        {.port = 0x3A0, .irq = 0},
        {.port = 0x3C0, .irq = 0},
        {.port = 0x3E0, .irq = 0},
        {.port = 0,     .irq = 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

/*
 . DEBUGGING LEVELS
 .
 . 0 for normal operation
 . 1 for slightly more details
 . >2 for various levels of increasingly useless information
 .    2 for interrupt tracking, status flags
 .    3 for packet dumps, etc.
*/
#define SMC_DEBUG 0

#if (SMC_DEBUG > 2 )
#define PRINTK3(x) printk x
#else
#define PRINTK3(x)
#endif

#if SMC_DEBUG > 1
#define PRINTK2(x) printk x
#else
#define PRINTK2(x)
#endif

#ifdef SMC_DEBUG
#define PRINTK(x) printk x
#else
#define PRINTK(x)
#endif


/*------------------------------------------------------------------------
 .
 . The internal workings of the driver.  If you are changing anything
 . here with the SMC stuff, you should have the datasheet and known
 . what you are doing.
 .
 -------------------------------------------------------------------------*/
#define CARDNAME "SMC9194"


/* store this information for the driver.. */
struct smc_local {
        /*
           If I have to wait until memory is available to send
           a packet, I will store the skbuff here, until I get the
           desired memory.  Then, I'll send it out and free it.
        */
        struct sk_buff * saved_skb;

        /*
         . This keeps track of how many packets that I have
         . sent out.  When an TX_EMPTY interrupt comes, I know
         . that all of these have been sent.
        */
        int     packets_waiting;
};


/*-----------------------------------------------------------------
 .
 .  The driver can be entered at any of the following entry points.
 .
 .------------------------------------------------------------------  */

/*
 . This is called by  register_netdev().  It is responsible for
 . checking the portlist for the SMC9000 series chipset.  If it finds
 . one, then it will initialize the device, find the hardware information,
 . and sets up the appropriate device parameters.
 . NOTE: Interrupts are *OFF* when this procedure is called.
 .
 . NB:This shouldn't be static since it is referred to externally.
*/
struct net_device *smc_init(int unit);

/*
 . The kernel calls this function when someone wants to use the device,
 . typically 'ifconfig ethX up'.
*/
static int smc_open(struct net_device *dev);

/*
 . Our watchdog timed out. Called by the networking layer
*/
static void smc_timeout(struct net_device *dev);

/*
 . This is called by the kernel in response to 'ifconfig ethX down'.  It
 . is responsible for cleaning up everything that the open routine
 . does, and maybe putting the card into a powerdown state.
*/
static int smc_close(struct net_device *dev);

/*
 . Finally, a call to set promiscuous mode ( for TCPDUMP and related
 . programs ) and multicast modes.
*/
static void smc_set_multicast_list(struct net_device *dev);


/*---------------------------------------------------------------
 .
 . Interrupt level calls..
 .
 ----------------------------------------------------------------*/

/*
 . Handles the actual interrupt
*/
static irqreturn_t smc_interrupt(int irq, void *);
/*
 . This is a separate procedure to handle the receipt of a packet, to
 . leave the interrupt code looking slightly cleaner
*/
static inline void smc_rcv( struct net_device *dev );
/*
 . This handles a TX interrupt, which is only called when an error
 . relating to a packet is sent.
*/
static inline void smc_tx( struct net_device * dev );

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

/*
 . Test if a given location contains a chip, trying to cause as
 . little damage as possible if it's not a SMC chip.
*/
static int smc_probe(struct net_device *dev, int ioaddr);

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

#define tx_done(dev) 1

/* this is called to actually send the packet to the chip */
static void smc_hardware_send_packet( struct net_device * dev );

/* Since I am not sure if I will have enough room in the chip's ram
 . to store the packet, I call this routine, which either sends it
 . now, or generates an interrupt when the card is ready for the
 . packet */
static netdev_tx_t  smc_wait_to_send_packet( struct sk_buff * skb,
                                             struct net_device *dev );

/* this does a soft reset on the device */
static void smc_reset( int ioaddr );

/* Enable Interrupts, Receive, and Transmit */
static void smc_enable( int ioaddr );

/* this puts the device in an inactive state */
static void smc_shutdown( int ioaddr );

/* This routine will find the IRQ of the driver if one is not
 . specified in the input to the device.  */
static int smc_findirq( int ioaddr );

/*
 . Function: smc_reset( int ioaddr )
 . Purpose:
 .      This sets the SMC91xx 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?  SOFTRESET  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( int ioaddr )
{
        /* This resets the registers mostly to defaults, but doesn't
           affect EEPROM.  That seems unnecessary */
        SMC_SELECT_BANK( 0 );
        outw( RCR_SOFTRESET, ioaddr + RCR );

        /* this should pause enough for the chip to be happy */
        SMC_DELAY( );

        /* Set the transmit and receive configuration registers to
           default values */
        outw( RCR_CLEAR, ioaddr + RCR );
        outw( TCR_CLEAR, ioaddr + TCR );

        /* set the control register to automatically
           release successfully transmitted packets, to make the best
           use out of our limited memory */
        SMC_SELECT_BANK( 1 );
        outw( inw( ioaddr + CONTROL ) | CTL_AUTO_RELEASE , ioaddr + CONTROL );

        /* Reset the MMU */
        SMC_SELECT_BANK( 2 );
        outw( MC_RESET, ioaddr + MMU_CMD );

        /* Note:  It doesn't seem that waiting for the MMU busy is needed here,
           but this is a place where future chipsets _COULD_ break.  Be wary
           of issuing another MMU command right after this */

        outb( 0, ioaddr + INT_MASK );
}

/*
 . Function: smc_enable
 . Purpose: let the chip talk to the outside work
 . Method:
 .      1.  Enable the transmitter
 .      2.  Enable the receiver
 .      3.  Enable interrupts
*/
static void smc_enable( int ioaddr )
{
        SMC_SELECT_BANK( 0 );
        /* see the header file for options in TCR/RCR NORMAL*/
        outw( TCR_NORMAL, ioaddr + TCR );
        outw( RCR_NORMAL, ioaddr + RCR );

        /* now, enable interrupts */
        SMC_SELECT_BANK( 2 );
        outb( SMC_INTERRUPT_MASK, ioaddr + INT_MASK );
}

/*
 . 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( int ioaddr )
{
        /* no more interrupts for me */
        SMC_SELECT_BANK( 2 );
        outb( 0, ioaddr + INT_MASK );

        /* and tell the card to stay away from that nasty outside world */
        SMC_SELECT_BANK( 0 );
        outb( RCR_CLEAR, ioaddr + RCR );
        outb( TCR_CLEAR, ioaddr + TCR );
#if 0
        /* finally, shut the chip down */
        SMC_SELECT_BANK( 1 );
        outw( inw( ioaddr + CONTROL ), CTL_POWERDOWN, ioaddr + CONTROL  );
#endif
}


/*
 . Function: smc_setmulticast( int ioaddr, struct net_device *dev )
 . Purpose:
 .    This sets the internal hardware table to filter out unwanted multicast
 .    packets before they take up memory.
 .
 .    The SMC chip uses a hash table where the high 6 bits of the CRC of
 .    address are the offset into the table.  If that bit is 1, then the
 .    multicast packet is accepted.  Otherwise, it's dropped silently.
 .
 .    To use the 6 bits as an offset into the table, the high 3 bits are the
 .    number of the 8 bit register, while the low 3 bits are the bit within
 .    that register.
 .
 . This routine is based very heavily on the one provided by Peter Cammaert.
*/


static void smc_setmulticast(int ioaddr, struct net_device *dev)
{
        int                     i;
        unsigned char           multicast_table[ 8 ];
        struct netdev_hw_addr *ha;
        /* table for flipping the order of 3 bits */
        unsigned char invert3[] = { 0, 4, 2, 6, 1, 5, 3, 7 };

        /* start with a table of all zeros: reject all */
        memset( multicast_table, 0, sizeof( multicast_table ) );

        netdev_for_each_mc_addr(ha, dev) {
                int position;

                /* only use the low order bits */
                position = ether_crc_le(6, ha->addr) & 0x3f;

                /* do some messy swapping to put the bit in the right spot */
                multicast_table[invert3[position&7]] |=
                                        (1<<invert3[(position>>3)&7]);

        }
        /* now, the table can be loaded into the chipset */
        SMC_SELECT_BANK( 3 );

        for ( i = 0; i < 8 ; i++ ) {
                outb( multicast_table[i], ioaddr + MULTICAST1 + i );
        }
}

/*
 . Function: smc_wait_to_send_packet( struct sk_buff * skb, struct net_device * )
 . Purpose:
 .    Attempt to allocate memory for a packet, if chip-memory is not
 .    available, then tell the card to generate an interrupt when it
 .    is available.
 .
 . Algorithm:
 .
 . o    if the saved_skb is not currently null, then drop this packet
 .      on the floor.  This should never happen, because of TBUSY.
 . o    if the saved_skb is null, then replace it with the current packet,
 . o    See if I can sending it now.
 . o    (NO): Enable interrupts and let the interrupt handler deal with it.
 . o    (YES):Send it now.
*/
static netdev_tx_t smc_wait_to_send_packet(struct sk_buff *skb,
                                           struct net_device *dev)
{
        struct smc_local *lp = netdev_priv(dev);
        unsigned int ioaddr     = dev->base_addr;
        word                    length;
        unsigned short          numPages;
        word                    time_out;

        netif_stop_queue(dev);
        /* Well, I want to send the packet.. but I don't know
           if I can send it right now...  */

        if ( lp->saved_skb) {
                /* THIS SHOULD NEVER HAPPEN. */
                dev->stats.tx_aborted_errors++;
                printk(CARDNAME": Bad Craziness - sent packet while busy.\n" );
                return NETDEV_TX_BUSY;
        }
        lp->saved_skb = skb;

        length = skb->len;

        if (length < ETH_ZLEN) {
                if (skb_padto(skb, ETH_ZLEN)) {
                        netif_wake_queue(dev);
                        return NETDEV_TX_OK;
                }
                length = ETH_ZLEN;
        }

        /*
        ** 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 :) )
        **
        ** Pkt size for allocating is data length +6 (for additional status words,
        ** length and ctl!) If odd size last byte is included in this header.
        */
        numPages =  ((length & 0xfffe) + 6) / 256;

        if (numPages > 7 ) {
                printk(CARDNAME": Far too big packet error.\n");
                /* freeing the packet is a good thing here... but should
                 . any packets of this size get down here?   */
                dev_kfree_skb (skb);
                lp->saved_skb = NULL;
                /* this IS an error, but, i don't want the skb saved */
                netif_wake_queue(dev);
                return NETDEV_TX_OK;
        }
        /* either way, a packet is waiting now */
        lp->packets_waiting++;

        /* now, try to allocate the memory */
        SMC_SELECT_BANK( 2 );
        outw( MC_ALLOC | numPages, ioaddr + MMU_CMD );
        /*
        . Performance Hack
        .
        . wait a short amount of time.. if I can send a packet now, I send
        . it now.  Otherwise, I enable an interrupt and wait for one to be
        . available.
        .
        . I could have handled this a slightly different way, by checking to
        . see if any memory was available in the FREE MEMORY register.  However,
        . either way, I need to generate an allocation, and the allocation works
        . no matter what, so I saw no point in checking free memory.
        */
        time_out = MEMORY_WAIT_TIME;
        do {
                word    status;

                status = inb( ioaddr + INTERRUPT );
                if ( status & IM_ALLOC_INT ) {
                        /* acknowledge the interrupt */
                        outb( IM_ALLOC_INT, ioaddr + INTERRUPT );
                        break;
                }
        } while ( -- time_out );

        if ( !time_out ) {
                /* oh well, wait until the chip finds memory later */
                SMC_ENABLE_INT( IM_ALLOC_INT );
                PRINTK2((CARDNAME": memory allocation deferred.\n"));
                /* it's deferred, but I'll handle it later */
                return NETDEV_TX_OK;
        }
        /* or YES! I can send the packet now.. */
        smc_hardware_send_packet(dev);
        netif_wake_queue(dev);
        return NETDEV_TX_OK;
}

/*
 . 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 void smc_hardware_send_packet( struct net_device * dev )
{
        struct smc_local *lp = netdev_priv(dev);
        byte                    packet_no;
        struct sk_buff *        skb = lp->saved_skb;
        word                    length;
        unsigned int            ioaddr;
        byte                    * buf;

        ioaddr = dev->base_addr;

        if ( !skb ) {
                PRINTK((CARDNAME": In XMIT with no packet to send\n"));
                return;
        }
        length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
        buf = skb->data;

        /* If I get here, I _know_ there is a packet slot waiting for me */
        packet_no = inb( ioaddr + PNR_ARR + 1 );
        if ( packet_no & 0x80 ) {
                /* or isn't there?  BAD CHIP! */
                netdev_dbg(dev, CARDNAME": Memory allocation failed.\n");
                dev_kfree_skb_any(skb);
                lp->saved_skb = NULL;
                netif_wake_queue(dev);
                return;
        }

        /* we have a packet address, so tell the card to use it */
        outb( packet_no, ioaddr + PNR_ARR );

        /* point to the beginning of the packet */
        outw( PTR_AUTOINC , ioaddr + POINTER );

        PRINTK3((CARDNAME": Trying to xmit packet of length %x\n", length));
#if SMC_DEBUG > 2
        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
        outl(  (length +6 ) << 16 , ioaddr + DATA_1 );
#else
        outw( 0, ioaddr + DATA_1 );
        /* send the packet length ( +6 for status words, length, and ctl*/
        outb( (length+6) & 0xFF,ioaddr + DATA_1 );
        outb( (length+6) >> 8 , ioaddr + DATA_1 );
#endif

        /* 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
        if ( length & 0x2  ) {
                outsl(ioaddr + DATA_1, buf,  length >> 2 );
                outw( *((word *)(buf + (length & 0xFFFFFFFC))),ioaddr +DATA_1);
        }
        else
                outsl(ioaddr + DATA_1, buf,  length >> 2 );
#else
        outsw(ioaddr + DATA_1 , buf, (length ) >> 1);
#endif
        /* Send the last byte, if there is one.   */

        if ( (length & 1) == 0 ) {
                outw( 0, ioaddr + DATA_1 );
        } else {
                outb( buf[length -1 ], ioaddr + DATA_1 );
                outb( 0x20, ioaddr + DATA_1);
        }

        /* enable the interrupts */
        SMC_ENABLE_INT( (IM_TX_INT | IM_TX_EMPTY_INT) );

        /* and let the chipset deal with it */
        outw( MC_ENQUEUE , ioaddr + MMU_CMD );

        PRINTK2((CARDNAME": Sent packet of length %d\n", length));

        lp->saved_skb = NULL;
        dev_kfree_skb_any (skb);

        dev->trans_start = jiffies;

        /* we can send another packet */
        netif_wake_queue(dev);
}

/*-------------------------------------------------------------------------
 |
 | smc_init(int unit)
 |   Input parameters:
 |      dev->base_addr == 0, try to find all possible locations
 |      dev->base_addr == 1, return failure code
 |      dev->base_addr == 2, always allocate space,  and return success
 |      dev->base_addr == <anything else>   this is the address to check
 |
 |   Output:
 |      pointer to net_device or ERR_PTR(error)
 |
 ---------------------------------------------------------------------------
*/
static int io;
static int irq;
static int ifport;

struct net_device * __init smc_init(int unit)
{
        struct net_device *dev = alloc_etherdev(sizeof(struct smc_local));
        struct devlist *smcdev = smc_devlist;
        int err = 0;

        if (!dev)
                return ERR_PTR(-ENODEV);

        if (unit >= 0) {
                sprintf(dev->name, "eth%d", unit);
                netdev_boot_setup_check(dev);
                io = dev->base_addr;
                irq = dev->irq;
        }

        if (io > 0x1ff) {       /* Check a single specified location. */
                err = smc_probe(dev, io);
        } else if (io != 0) {   /* Don't probe at all. */
                err = -ENXIO;
        } else {
                for (;smcdev->port; smcdev++) {
                        if (smc_probe(dev, smcdev->port) == 0)
                                break;
                }
                if (!smcdev->port)
                        err = -ENODEV;
        }
        if (err)
                goto out;
        err = register_netdev(dev);
        if (err)
                goto out1;
        return dev;
out1:
        free_irq(dev->irq, dev);
        release_region(dev->base_addr, SMC_IO_EXTENT);
out:
        free_netdev(dev);
        return ERR_PTR(err);
}

/*----------------------------------------------------------------------
 . smc_findirq
 .
 . This routine has a simple purpose -- make the SMC chip generate an
 . interrupt, so an auto-detect routine can detect it, and find the IRQ,
 ------------------------------------------------------------------------
*/
static int __init smc_findirq(int ioaddr)
{
#ifndef NO_AUTOPROBE
        int     timeout = 20;
        unsigned long cookie;


        cookie = probe_irq_on();

        /*
         * What I try to do here is trigger an ALLOC_INT. This is done
         * by allocating a small chunk of memory, which will give an interrupt
         * when done.
         */


        SMC_SELECT_BANK(2);
        /* enable ALLOCation interrupts ONLY */
        outb( IM_ALLOC_INT, ioaddr + INT_MASK );

        /*
         . Allocate 512 bytes of memory.  Note that the chip was just
         . reset so all the memory is available
        */
        outw( MC_ALLOC | 1, ioaddr + MMU_CMD );

        /*
         . Wait until positive that the interrupt has been generated
        */
        while ( timeout ) {
                byte    int_status;

                int_status = inb( ioaddr + INTERRUPT );

                if ( int_status & IM_ALLOC_INT )
                        break;          /* got the interrupt */
                timeout--;
        }
        /* there is really nothing that I can do here if timeout fails,
           as probe_irq_off will return a 0 anyway, which is what I
           want in this case.   Plus, the clean up is needed in both
           cases.  */

        /* DELAY HERE!
           On a fast machine, the status might change before the interrupt
           is given to the processor.  This means that the interrupt was
           never detected, and probe_irq_off fails to report anything.
           This should fix probe_irq_* problems.
        */
        SMC_DELAY();
        SMC_DELAY();

        /* and disable all interrupts again */
        outb( 0, ioaddr + INT_MASK );

        /* and return what I found */
        return probe_irq_off(cookie);
#else /* NO_AUTOPROBE */
        struct devlist *smcdev;
        for (smcdev = smc_devlist; smcdev->port; smcdev++) {
                if (smcdev->port == ioaddr)
                        return smcdev->irq;
        }
        return 0;
#endif
}

static const struct net_device_ops smc_netdev_ops = {
        .ndo_open                = smc_open,
        .ndo_stop               = smc_close,
        .ndo_start_xmit         = smc_wait_to_send_packet,
        .ndo_tx_timeout         = smc_timeout,
        .ndo_set_rx_mode        = smc_set_multicast_list,
        .ndo_change_mtu         = eth_change_mtu,
        .ndo_set_mac_address    = eth_mac_addr,
        .ndo_validate_addr      = eth_validate_addr,
};

/*----------------------------------------------------------------------
 . Function: smc_probe( int ioaddr )
 .
 . Purpose:
 .      Tests to see if a given ioaddr points to an SMC9xxx chip.
 .      Returns a 0 on success
 .
 . Algorithm:
 .      (1) see if the high byte of BANK_SELECT is 0x33
 .      (2) compare the ioaddr with the base register's address
 .      (3) see if I recognize the chip ID in the appropriate register
 .
 .---------------------------------------------------------------------
 */

/*---------------------------------------------------------------
 . Here I do typical initialization tasks.
 .
 . o  Initialize the structure if needed
 . o  print out my vanity message if not done so already
 . o  print out what type of hardware is detected
 . o  print out the ethernet address
 . o  find the IRQ
 . o  set up my private data
 . o  configure the dev structure with my subroutines
 . o  actually GRAB the irq.
 . o  GRAB the region
 .-----------------------------------------------------------------
*/
static int __init smc_probe(struct net_device *dev, int ioaddr)
{
        int i, memory, retval;
        unsigned int bank;

        const char *version_string;
        const char *if_string;

        /* registers */
        word revision_register;
        word base_address_register;
        word configuration_register;
        word memory_info_register;
        word memory_cfg_register;

        /* Grab the region so that no one else tries to probe our ioports. */
        if (!request_region(ioaddr, SMC_IO_EXTENT, DRV_NAME))
                return -EBUSY;

        dev->irq = irq;
        dev->if_port = ifport;

        /* First, see if the high byte is 0x33 */
        bank = inw( ioaddr + BANK_SELECT );
        if ( (bank & 0xFF00) != 0x3300 ) {
                retval = -ENODEV;
                goto err_out;
        }
        /* The above MIGHT indicate a device, but I need to write to further
                test this.  */
        outw( 0x0, ioaddr + BANK_SELECT );
        bank = inw( ioaddr + BANK_SELECT );
        if ( (bank & 0xFF00 ) != 0x3300 ) {
                retval = -ENODEV;
                goto err_out;
        }
        /* well, we've already written once, so hopefully another time won't
           hurt.  This time, I need to switch the bank register to bank 1,
           so I can access the base address register */
        SMC_SELECT_BANK(1);
        base_address_register = inw( ioaddr + BASE );
        if ( ioaddr != ( base_address_register >> 3 & 0x3E0 ) )  {
                printk(CARDNAME ": IOADDR %x doesn't match configuration (%x). "
                        "Probably not a SMC chip\n",
                        ioaddr, base_address_register >> 3 & 0x3E0 );
                /* well, the base address register didn't match.  Must not have
                   been a SMC chip after all. */
                retval = -ENODEV;
                goto err_out;
        }

        /*  check if the revision register is something that I recognize.
            These might need to be added to later, as future revisions
            could be added.  */
        SMC_SELECT_BANK(3);
        revision_register  = inw( ioaddr + REVISION );
        if ( !chip_ids[ ( revision_register  >> 4 ) & 0xF  ] ) {
                /* I don't recognize this chip, so... */
                printk(CARDNAME ": IO %x: Unrecognized revision register:"
                        " %x, Contact author.\n", ioaddr, revision_register);

                retval = -ENODEV;
                goto err_out;
        }

        /* at this point I'll assume that the chip is an SMC9xxx.
           It might be prudent to check a listing of MAC addresses
           against the hardware address, or do some other tests. */

        pr_info_once("%s\n", version);

        /* fill in some of the fields */
        dev->base_addr = ioaddr;

        /*
         . Get the MAC address ( bank 1, regs 4 - 9 )
        */
        SMC_SELECT_BANK( 1 );
        for ( i = 0; i < 6; i += 2 ) {
                word    address;

                address = inw( ioaddr + ADDR0 + i  );
                dev->dev_addr[ i + 1] = address >> 8;
                dev->dev_addr[ i ] = address & 0xFF;
        }

        /* get the memory information */

        SMC_SELECT_BANK( 0 );
        memory_info_register = inw( ioaddr + MIR );
        memory_cfg_register  = inw( ioaddr + MCR );
        memory = ( memory_cfg_register >> 9 )  & 0x7;  /* multiplier */
        memory *= 256 * ( memory_info_register & 0xFF );

        /*
         Now, I want to find out more about the chip.  This is sort of
         redundant, but it's cleaner to have it in both, rather than having
         one VERY long probe procedure.
        */
        SMC_SELECT_BANK(3);
        revision_register  = inw( ioaddr + REVISION );
        version_string = chip_ids[ ( revision_register  >> 4 ) & 0xF  ];
        if ( !version_string ) {
                /* I shouldn't get here because this call was done before.... */
                retval = -ENODEV;
                goto err_out;
        }

        /* is it using AUI or 10BaseT ? */
        if ( dev->if_port == 0 ) {
                SMC_SELECT_BANK(1);
                configuration_register = inw( ioaddr + CONFIG );
                if ( configuration_register & CFG_AUI_SELECT )
                        dev->if_port = 2;
                else
                        dev->if_port = 1;
        }
        if_string = interfaces[ dev->if_port - 1 ];

        /* now, reset the chip, and put it into a known state */
        smc_reset( ioaddr );

        /*
         . If dev->irq is 0, then the device has to be banged on to see
         . what the IRQ is.
         .
         . This banging doesn't always detect the IRQ, for unknown reasons.
         . a workaround is to reset the chip and try again.
         .
         . Interestingly, the DOS packet driver *SETS* the IRQ on the card to
         . be what is requested on the command line.   I don't do that, mostly
         . because the card that I have uses a non-standard method of accessing
         . the IRQs, and because this _should_ work in most configurations.
         .
         . Specifying an IRQ is done with the assumption that the user knows
         . what (s)he is doing.  No checking is done!!!!
         .
        */
        if ( dev->irq < 2 ) {
                int     trials;

                trials = 3;
                while ( trials-- ) {
                        dev->irq = smc_findirq( ioaddr );
                        if ( dev->irq )
                                break;
                        /* kick the card and try again */
                        smc_reset( ioaddr );
                }
        }
        if (dev->irq == 0 ) {
                printk(CARDNAME": Couldn't autodetect your IRQ. Use irq=xx.\n");
                retval = -ENODEV;
                goto err_out;
        }

        /* now, print out the card info, in a short format.. */

        netdev_info(dev, "%s(r:%d) at %#3x IRQ:%d INTF:%s MEM:%db ",
                    version_string, revision_register & 0xF, ioaddr, dev->irq,
                    if_string, memory);
        /*
         . Print the Ethernet address
        */
        netdev_info(dev, "ADDR: %pM\n", dev->dev_addr);

        /* Grab the IRQ */
        retval = request_irq(dev->irq, smc_interrupt, 0, DRV_NAME, dev);
        if (retval) {
                netdev_warn(dev, "%s: unable to get IRQ %d (irqval=%d).\n",
                            DRV_NAME, dev->irq, retval);
                goto err_out;
        }

        dev->netdev_ops                 = &smc_netdev_ops;
        dev->watchdog_timeo             = HZ/20;

        return 0;

err_out:
        release_region(ioaddr, SMC_IO_EXTENT);
        return retval;
}

#if SMC_DEBUG > 2
static void print_packet( byte * buf, int length )
{
#if 0
        print_hex_dump_debug(DRV_NAME, DUMP_PREFIX_OFFSET, 16, 1,
                             buf, length, true);
#endif
}
#endif


/*
 * Open and Initialize the board
 *
 * Set up everything, reset the card, etc ..
 *
 */
static int smc_open(struct net_device *dev)
{
        int     ioaddr = dev->base_addr;

        int     i;      /* used to set hw ethernet address */

        /* clear out all the junk that was put here before... */
        memset(netdev_priv(dev), 0, sizeof(struct smc_local));

        /* reset the hardware */

        smc_reset( ioaddr );
        smc_enable( ioaddr );

        /* Select which interface to use */

        SMC_SELECT_BANK( 1 );
        if ( dev->if_port == 1 ) {
                outw( inw( ioaddr + CONFIG ) & ~CFG_AUI_SELECT,
                        ioaddr + CONFIG );
        }
        else if ( dev->if_port == 2 ) {
                outw( inw( ioaddr + CONFIG ) | CFG_AUI_SELECT,
                        ioaddr + CONFIG );
        }

        /*
                According to Becker, I have to set the hardware address
                at this point, because the (l)user can set it with an
                ioctl.  Easily done...
        */
        SMC_SELECT_BANK( 1 );
        for ( i = 0; i < 6; i += 2 ) {
                word    address;

                address = dev->dev_addr[ i + 1 ] << 8 ;
                address  |= dev->dev_addr[ i ];
                outw( address, ioaddr + ADDR0 + i );
        }

        netif_start_queue(dev);
        return 0;
}

/*--------------------------------------------------------
 . Called by the kernel to send a packet out into the void
 . of the net.  This routine is largely based on
 . skeleton.c, from Becker.
 .--------------------------------------------------------
*/

static void smc_timeout(struct net_device *dev)
{
        /* If we get here, some higher level has decided we are broken.
           There should really be a "kick me" function call instead. */
        netdev_warn(dev, CARDNAME": transmit timed out, %s?\n",
                    tx_done(dev) ? "IRQ conflict" : "network cable problem");
        /* "kick" the adaptor */
        smc_reset( dev->base_addr );
        smc_enable( dev->base_addr );
        dev->trans_start = jiffies; /* prevent tx timeout */
        /* clear anything saved */
        ((struct smc_local *)netdev_priv(dev))->saved_skb = NULL;
        netif_wake_queue(dev);
}

/*-------------------------------------------------------------
 .
 . 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 void smc_rcv(struct net_device *dev)
{
        int     ioaddr = dev->base_addr;
        int     packet_number;
        word    status;
        word    packet_length;

        /* assume bank 2 */

        packet_number = inw( ioaddr + FIFO_PORTS );

        if ( packet_number & FP_RXEMPTY ) {
                /* we got called , but nothing was on the FIFO */
                PRINTK((CARDNAME ": WARNING: smc_rcv with nothing on FIFO.\n"));
                /* don't need to restore anything */
                return;
        }

        /*  start reading from the start of the packet */
        outw( PTR_READ | PTR_RCV | PTR_AUTOINC, ioaddr + POINTER );

        /* First two words are status and packet_length */
        status          = inw( ioaddr + DATA_1 );
        packet_length   = inw( ioaddr + DATA_1 );

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

        PRINTK2(("RCV: STATUS %4x LENGTH %4x\n", status, packet_length ));
        /*
         . the packet length contains 3 extra words :
         . status, length, and an extra word with an odd byte .
        */
        packet_length -= 6;

        if ( !(status & RS_ERRORS ) ){
                /* do stuff to make a new packet */
                struct sk_buff  * skb;
                byte            * data;

                /* read one extra byte */
                if ( status & RS_ODDFRAME )
                        packet_length++;

                /* set multicast stats */
                if ( status & RS_MULTICAST )
                        dev->stats.multicast++;

                skb = netdev_alloc_skb(dev, packet_length + 5);
                if ( skb == NULL ) {
                        dev->stats.rx_dropped++;
                        goto done;
                }

                /*
                 ! This should work without alignment, but it could be
                 ! in the worse case
                */

                skb_reserve( skb, 2 );   /* 16 bit alignment */

                data = skb_put( skb, packet_length);

#ifdef USE_32_BIT
                /* 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  */
                PRINTK3((" Reading %d dwords (and %d bytes)\n",
                        packet_length >> 2, packet_length & 3 ));
                insl(ioaddr + DATA_1 , data, packet_length >> 2 );
                /* read the left over bytes */
                insb( ioaddr + DATA_1, data + (packet_length & 0xFFFFFC),
                        packet_length & 0x3  );
#else
                PRINTK3((" Reading %d words and %d byte(s)\n",
                        (packet_length >> 1 ), packet_length & 1 ));
                insw(ioaddr + DATA_1 , data, packet_length >> 1);
                if ( packet_length & 1 ) {
                        data += packet_length & ~1;
                        *(data++) = inb( ioaddr + DATA_1 );
                }
#endif
#if     SMC_DEBUG > 2
                        print_packet( data, packet_length );
#endif

                skb->protocol = eth_type_trans(skb, dev );
                netif_rx(skb);
                dev->stats.rx_packets++;
                dev->stats.rx_bytes += packet_length;
        } else {
                /* error ... */
                dev->stats.rx_errors++;

                if ( status & RS_ALGNERR )  dev->stats.rx_frame_errors++;
                if ( status & (RS_TOOSHORT | RS_TOOLONG ) )
                        dev->stats.rx_length_errors++;
                if ( status & RS_BADCRC)        dev->stats.rx_crc_errors++;
        }

done:
        /*  error or good, tell the card to get rid of this packet */
        outw( MC_RELEASE, ioaddr + MMU_CMD );
}


/*************************************************************************
 . smc_tx
 .
 . Purpose:  Handle a transmit error message.   This will only be called
 .   when an error, because of the AUTO_RELEASE mode.
 .
 . Algorithm:
 .      Save pointer and packet no
 .      Get the packet no from the top of the queue
 .      check if it's valid ( if not, is this an error??? )
 .      read the status word
 .      record the error
 .      ( resend?  Not really, since we don't want old packets around )
 .      Restore saved values
 ************************************************************************/
static void smc_tx( struct net_device * dev )
{
        int     ioaddr = dev->base_addr;
        struct smc_local *lp = netdev_priv(dev);
        byte saved_packet;
        byte packet_no;
        word tx_status;


        /* assume bank 2  */

        saved_packet = inb( ioaddr + PNR_ARR );
        packet_no = inw( ioaddr + FIFO_PORTS );
        packet_no &= 0x7F;

        /* select this as the packet to read from */
        outb( packet_no, ioaddr + PNR_ARR );

        /* read the first word from this packet */
        outw( PTR_AUTOINC | PTR_READ, ioaddr + POINTER );

        tx_status = inw( ioaddr + DATA_1 );
        PRINTK3((CARDNAME": TX DONE STATUS: %4x\n", tx_status));

        dev->stats.tx_errors++;
        if ( tx_status & TS_LOSTCAR ) dev->stats.tx_carrier_errors++;
        if ( tx_status & TS_LATCOL  ) {
                netdev_dbg(dev, CARDNAME": Late collision occurred on last xmit.\n");
                dev->stats.tx_window_errors++;
        }
#if 0
                if ( tx_status & TS_16COL ) { ... }
#endif

        if ( tx_status & TS_SUCCESS ) {
                netdev_info(dev, CARDNAME": Successful packet caused interrupt\n");
        }
        /* re-enable transmit */
        SMC_SELECT_BANK( 0 );
        outw( inw( ioaddr + TCR ) | TCR_ENABLE, ioaddr + TCR );

        /* kill the packet */
        SMC_SELECT_BANK( 2 );
        outw( MC_FREEPKT, ioaddr + MMU_CMD );

        /* one less packet waiting for me */
        lp->packets_waiting--;

        outb( saved_packet, ioaddr + PNR_ARR );
}

/*--------------------------------------------------------------------
 .
 . This is the main routine of the driver, to handle the device when
 . it needs some attention.
 .
 . So:
 .   first, save state of the chipset
 .   branch off into routines to handle each case, and acknowledge
 .          each to the interrupt register
 .   and finally restore state.
 .
 ---------------------------------------------------------------------*/

static irqreturn_t smc_interrupt(int irq, void * dev_id)
{
        struct net_device *dev  = dev_id;
        int ioaddr              = dev->base_addr;
        struct smc_local *lp = netdev_priv(dev);

        byte    status;
        word    card_stats;
        byte    mask;
        int     timeout;
        /* state registers */
        word    saved_bank;
        word    saved_pointer;
        int handled = 0;


        PRINTK3((CARDNAME": SMC interrupt started\n"));

        saved_bank = inw( ioaddr + BANK_SELECT );

        SMC_SELECT_BANK(2);
        saved_pointer = inw( ioaddr + POINTER );

        mask = inb( ioaddr + INT_MASK );
        /* clear all interrupts */
        outb( 0, ioaddr + INT_MASK );


        /* set a timeout value, so I don't stay here forever */
        timeout = 4;

        PRINTK2((KERN_WARNING CARDNAME ": MASK IS %x\n", mask));
        do {
                /* read the status flag, and mask it */
                status = inb( ioaddr + INTERRUPT ) & mask;
                if (!status )
                        break;

                handled = 1;

                PRINTK3((KERN_WARNING CARDNAME
                        ": Handling interrupt status %x\n", status));

                if (status & IM_RCV_INT) {
                        /* Got a packet(s). */
                        PRINTK2((KERN_WARNING CARDNAME
                                ": Receive Interrupt\n"));
                        smc_rcv(dev);
                } else if (status & IM_TX_INT ) {
                        PRINTK2((KERN_WARNING CARDNAME
                                ": TX ERROR handled\n"));
                        smc_tx(dev);
                        outb(IM_TX_INT, ioaddr + INTERRUPT );
                } else if (status & IM_TX_EMPTY_INT ) {
                        /* update stats */
                        SMC_SELECT_BANK( 0 );
                        card_stats = inw( ioaddr + COUNTER );
                        /* single collisions */
                        dev->stats.collisions += card_stats & 0xF;
                        card_stats >>= 4;
                        /* multiple collisions */
                        dev->stats.collisions += card_stats & 0xF;

                        /* these are for when linux supports these statistics */

                        SMC_SELECT_BANK( 2 );
                        PRINTK2((KERN_WARNING CARDNAME
                                ": TX_BUFFER_EMPTY handled\n"));
                        outb( IM_TX_EMPTY_INT, ioaddr + INTERRUPT );
                        mask &= ~IM_TX_EMPTY_INT;
                        dev->stats.tx_packets += lp->packets_waiting;
                        lp->packets_waiting = 0;

                } else if (status & IM_ALLOC_INT ) {
                        PRINTK2((KERN_DEBUG CARDNAME
                                ": Allocation interrupt\n"));
                        /* clear this interrupt so it doesn't happen again */
                        mask &= ~IM_ALLOC_INT;

                        smc_hardware_send_packet( dev );

                        /* enable xmit interrupts based on this */
                        mask |= ( IM_TX_EMPTY_INT | IM_TX_INT );

                        /* and let the card send more packets to me */
                        netif_wake_queue(dev);

                        PRINTK2((CARDNAME": Handoff done successfully.\n"));
                } else if (status & IM_RX_OVRN_INT ) {
                        dev->stats.rx_errors++;
                        dev->stats.rx_fifo_errors++;
                        outb( IM_RX_OVRN_INT, ioaddr + INTERRUPT );
                } else if (status & IM_EPH_INT ) {
                        PRINTK((CARDNAME ": UNSUPPORTED: EPH INTERRUPT\n"));
                } else if (status & IM_ERCV_INT ) {
                        PRINTK((CARDNAME ": UNSUPPORTED: ERCV INTERRUPT\n"));
                        outb( IM_ERCV_INT, ioaddr + INTERRUPT );
                }
        } while ( timeout -- );


        /* restore state register */
        SMC_SELECT_BANK( 2 );
        outb( mask, ioaddr + INT_MASK );

        PRINTK3((KERN_WARNING CARDNAME ": MASK is now %x\n", mask));
        outw( saved_pointer, ioaddr + POINTER );

        SMC_SELECT_BANK( saved_bank );

        PRINTK3((CARDNAME ": Interrupt done\n"));
        return IRQ_RETVAL(handled);
}


/*----------------------------------------------------
 . 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 net_device *dev)
{
        netif_stop_queue(dev);
        /* clear everything */
        smc_shutdown( dev->base_addr );

        /* Update the statistics here. */
        return 0;
}

/*-----------------------------------------------------------
 . smc_set_multicast_list
 .
 . This routine will, depending on the values passed to it,
 . either make it accept multicast packets, go into
 . promiscuous mode ( for TCPDUMP and cousins ) or accept
 . a select set of multicast packets
*/
static void smc_set_multicast_list(struct net_device *dev)
{
        short ioaddr = dev->base_addr;

        SMC_SELECT_BANK(0);
        if ( dev->flags & IFF_PROMISC )
                outw( inw(ioaddr + RCR ) | RCR_PROMISC, ioaddr + RCR );

/* BUG?  I never disable promiscuous mode if multicasting was turned on.
   Now, I turn off promiscuous mode, but I don't do anything to multicasting
   when promiscuous mode is turned on.
*/

        /* Here, I am setting this to accept all multicast packets.
           I don't need to zero the multicast table, because the flag is
           checked before the table is
        */
        else if (dev->flags & IFF_ALLMULTI)
                outw( inw(ioaddr + RCR ) | RCR_ALMUL, ioaddr + RCR );

        /* We just get all multicast packets even if we only want them
         . from one source.  This will be changed at some future
         . point. */
        else if (!netdev_mc_empty(dev)) {
                /* support hardware multicasting */

                /* be sure I get rid of flags I might have set */
                outw( inw( ioaddr + RCR ) & ~(RCR_PROMISC | RCR_ALMUL),
                        ioaddr + RCR );
                /* NOTE: this has to set the bank, so make sure it is the
                   last thing called.  The bank is set to zero at the top */
                smc_setmulticast(ioaddr, dev);
        }
        else  {
                outw( inw( ioaddr + RCR ) & ~(RCR_PROMISC | RCR_ALMUL),
                        ioaddr + RCR );

                /*
                  since I'm disabling all multicast entirely, I need to
                  clear the multicast list
                */
                SMC_SELECT_BANK( 3 );
                outw( 0, ioaddr + MULTICAST1 );
                outw( 0, ioaddr + MULTICAST2 );
                outw( 0, ioaddr + MULTICAST3 );
                outw( 0, ioaddr + MULTICAST4 );
        }
}

#ifdef MODULE

static struct net_device *devSMC9194;
MODULE_LICENSE("GPL");

module_param(io, int, 0);
module_param(irq, int, 0);
module_param(ifport, int, 0);
MODULE_PARM_DESC(io, "SMC 99194 I/O base address");
MODULE_PARM_DESC(irq, "SMC 99194 IRQ number");
MODULE_PARM_DESC(ifport, "SMC 99194 interface port (0-default, 1-TP, 2-AUI)");

int __init init_module(void)
{
        if (io == 0)
                printk(KERN_WARNING
                CARDNAME": You shouldn't use auto-probing with insmod!\n" );

        /* copy the parameters from insmod into the device structure */
        devSMC9194 = smc_init(-1);
        return PTR_ERR_OR_ZERO(devSMC9194);
}

void __exit cleanup_module(void)
{
        unregister_netdev(devSMC9194);
        free_irq(devSMC9194->irq, devSMC9194);
        release_region(devSMC9194->base_addr, SMC_IO_EXTENT);
        free_netdev(devSMC9194);
}

#endif /* MODULE */