/* sbni.c:  Granch SBNI12 leased line adapters driver for linux
 *
 *      Written 2001 by Denis I.Timofeev (timofeev@granch.ru)
 *
 *      Previous versions were written by Yaroslav Polyakov,
 *      Alexey Zverev and Max Khon.
 *
 *      Driver supports SBNI12-02,-04,-05,-10,-11 cards, single and
 *      double-channel, PCI and ISA modifications.
 *      More info and useful utilities to work with SBNI12 cards you can find
 *      at http://www.granch.com (English) or http://www.granch.ru (Russian)
 *
 *      This software may be used and distributed according to the terms
 *      of the GNU General Public License.
 *
 *
 *  5.0.1       Jun 22 2001
 *        - Fixed bug in probe
 *  5.0.0       Jun 06 2001
 *        - Driver was completely redesigned by Denis I.Timofeev,
 *        - now PCI/Dual, ISA/Dual (with single interrupt line) models are
 *        - supported
 *  3.3.0       Thu Feb 24 21:30:28 NOVT 2000 
 *        - PCI cards support
 *  3.2.0       Mon Dec 13 22:26:53 NOVT 1999
 *        - Completely rebuilt all the packet storage system
 *        -    to work in Ethernet-like style.
 *  3.1.1       just fixed some bugs (5 aug 1999)
 *  3.1.0       added balancing feature (26 apr 1999)
 *  3.0.1       just fixed some bugs (14 apr 1999).
 *  3.0.0       Initial Revision, Yaroslav Polyakov (24 Feb 1999)
 *        - added pre-calculation for CRC, fixed bug with "len-2" frames, 
 *        - removed outbound fragmentation (MTU=1000), written CRC-calculation 
 *        - on asm, added work with hard_headers and now we have our own cache 
 *        - for them, optionally supported word-interchange on some chipsets,
 * 
 *      Known problem: this driver wasn't tested on multiprocessor machine.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ptrace.h>
#include <linux/fcntl.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/pci.h>
#include <linux/skbuff.h>
#include <linux/timer.h>
#include <linux/init.h>
#include <linux/delay.h>

#include <net/net_namespace.h>
#include <net/arp.h>
#include <net/Space.h>

#include <asm/io.h>
#include <asm/types.h>
#include <asm/byteorder.h>
#include <asm/irq.h>
#include <asm/uaccess.h>

#include "sbni.h"

/* device private data */

struct net_local {
        struct timer_list       watchdog;

        spinlock_t      lock;
        struct sk_buff  *rx_buf_p;              /* receive buffer ptr */
        struct sk_buff  *tx_buf_p;              /* transmit buffer ptr */
        
        unsigned int    framelen;               /* current frame length */
        unsigned int    maxframe;               /* maximum valid frame length */
        unsigned int    state;
        unsigned int    inppos, outpos;         /* positions in rx/tx buffers */

        /* transmitting frame number - from frames qty to 1 */
        unsigned int    tx_frameno;

        /* expected number of next receiving frame */
        unsigned int    wait_frameno;

        /* count of failed attempts to frame send - 32 attempts do before
           error - while receiver tunes on opposite side of wire */
        unsigned int    trans_errors;

        /* idle time; send pong when limit exceeded */
        unsigned int    timer_ticks;

        /* fields used for receive level autoselection */
        int     delta_rxl;
        unsigned int    cur_rxl_index, timeout_rxl;
        unsigned long   cur_rxl_rcvd, prev_rxl_rcvd;

        struct sbni_csr1        csr1;           /* current value of CSR1 */
        struct sbni_in_stats    in_stats;       /* internal statistics */ 

        struct net_device               *second;        /* for ISA/dual cards */

#ifdef CONFIG_SBNI_MULTILINE
        struct net_device               *master;
        struct net_device               *link;
#endif
};


static int  sbni_card_probe( unsigned long );
static int  sbni_pci_probe( struct net_device  * );
static struct net_device  *sbni_probe1(struct net_device *, unsigned long, int);
static int  sbni_open( struct net_device * );
static int  sbni_close( struct net_device * );
static netdev_tx_t sbni_start_xmit(struct sk_buff *,
                                         struct net_device * );
static int  sbni_ioctl( struct net_device *, struct ifreq *, int );
static void  set_multicast_list( struct net_device * );

static irqreturn_t sbni_interrupt( int, void * );
static void  handle_channel( struct net_device * );
static int   recv_frame( struct net_device * );
static void  send_frame( struct net_device * );
static int   upload_data( struct net_device *,
                          unsigned, unsigned, unsigned, u32 );
static void  download_data( struct net_device *, u32 * );
static void  sbni_watchdog( unsigned long );
static void  interpret_ack( struct net_device *, unsigned );
static int   append_frame_to_pkt( struct net_device *, unsigned, u32 );
static void  indicate_pkt( struct net_device * );
static void  card_start( struct net_device * );
static void  prepare_to_send( struct sk_buff *, struct net_device * );
static void  drop_xmit_queue( struct net_device * );
static void  send_frame_header( struct net_device *, u32 * );
static int   skip_tail( unsigned int, unsigned int, u32 );
static int   check_fhdr( u32, u32 *, u32 *, u32 *, u32 *, u32 * );
static void  change_level( struct net_device * );
static void  timeout_change_level( struct net_device * );
static u32   calc_crc32( u32, u8 *, u32 );
static struct sk_buff *  get_rx_buf( struct net_device * );
static int  sbni_init( struct net_device * );

#ifdef CONFIG_SBNI_MULTILINE
static int  enslave( struct net_device *, struct net_device * );
static int  emancipate( struct net_device * );
#endif

static const char  version[] =
        "Granch SBNI12 driver ver 5.0.1  Jun 22 2001  Denis I.Timofeev.\n";

static bool skip_pci_probe      __initdata = false;
static int  scandone    __initdata = 0;
static int  num         __initdata = 0;

static unsigned char  rxl_tab[];
static u32  crc32tab[];

/* A list of all installed devices, for removing the driver module. */
static struct net_device  *sbni_cards[ SBNI_MAX_NUM_CARDS ];

/* Lists of device's parameters */
static u32      io[   SBNI_MAX_NUM_CARDS ] __initdata =
        { [0 ... SBNI_MAX_NUM_CARDS-1] = -1 };
static u32      irq[  SBNI_MAX_NUM_CARDS ] __initdata;
static u32      baud[ SBNI_MAX_NUM_CARDS ] __initdata;
static u32      rxl[  SBNI_MAX_NUM_CARDS ] __initdata =
        { [0 ... SBNI_MAX_NUM_CARDS-1] = -1 };
static u32      mac[  SBNI_MAX_NUM_CARDS ] __initdata;

#ifndef MODULE
typedef u32  iarr[];
static iarr *dest[5] __initdata = { &io, &irq, &baud, &rxl, &mac };
#endif

/* A zero-terminated list of I/O addresses to be probed on ISA bus */
static unsigned int  netcard_portlist[ ] __initdata = { 
        0x210, 0x214, 0x220, 0x224, 0x230, 0x234, 0x240, 0x244, 0x250, 0x254,
        0x260, 0x264, 0x270, 0x274, 0x280, 0x284, 0x290, 0x294, 0x2a0, 0x2a4,
        0x2b0, 0x2b4, 0x2c0, 0x2c4, 0x2d0, 0x2d4, 0x2e0, 0x2e4, 0x2f0, 0x2f4,
        0 };

#define NET_LOCAL_LOCK(dev) (((struct net_local *)netdev_priv(dev))->lock)

/*
 * Look for SBNI card which addr stored in dev->base_addr, if nonzero.
 * Otherwise, look through PCI bus. If none PCI-card was found, scan ISA.
 */

static inline int __init
sbni_isa_probe( struct net_device  *dev )
{
        if( dev->base_addr > 0x1ff &&
            request_region( dev->base_addr, SBNI_IO_EXTENT, dev->name ) &&
            sbni_probe1( dev, dev->base_addr, dev->irq ) )

                return  0;
        else {
                pr_err("base address 0x%lx is busy, or adapter is malfunctional!\n",
                       dev->base_addr);
                return  -ENODEV;
        }
}

static const struct net_device_ops sbni_netdev_ops = {
        .ndo_open               = sbni_open,
        .ndo_stop               = sbni_close,
        .ndo_start_xmit         = sbni_start_xmit,
        .ndo_set_rx_mode        = set_multicast_list,
        .ndo_do_ioctl           = sbni_ioctl,
        .ndo_change_mtu         = eth_change_mtu,
        .ndo_set_mac_address    = eth_mac_addr,
        .ndo_validate_addr      = eth_validate_addr,
};

static void __init sbni_devsetup(struct net_device *dev)
{
        ether_setup( dev );
        dev->netdev_ops = &sbni_netdev_ops;
}

int __init sbni_probe(int unit)
{
        struct net_device *dev;
        int err;

        dev = alloc_netdev(sizeof(struct net_local), "sbni",
                           NET_NAME_UNKNOWN, sbni_devsetup);
        if (!dev)
                return -ENOMEM;

        dev->netdev_ops = &sbni_netdev_ops;

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

        err = sbni_init(dev);
        if (err) {
                free_netdev(dev);
                return err;
        }

        err = register_netdev(dev);
        if (err) {
                release_region( dev->base_addr, SBNI_IO_EXTENT );
                free_netdev(dev);
                return err;
        }
        pr_info_once("%s", version);
        return 0;
}

static int __init sbni_init(struct net_device *dev)
{
        int  i;
        if( dev->base_addr )
                return  sbni_isa_probe( dev );
        /* otherwise we have to perform search our adapter */

        if( io[ num ] != -1 )
                dev->base_addr  = io[ num ],
                dev->irq        = irq[ num ];
        else if( scandone  ||  io[ 0 ] != -1 )
                return  -ENODEV;

        /* if io[ num ] contains non-zero address, then that is on ISA bus */
        if( dev->base_addr )
                return  sbni_isa_probe( dev );

        /* ...otherwise - scan PCI first */
        if( !skip_pci_probe  &&  !sbni_pci_probe( dev ) )
                return  0;

        if( io[ num ] == -1 ) {
                /* Auto-scan will be stopped when first ISA card were found */
                scandone = 1;
                if( num > 0 )
                        return  -ENODEV;
        }

        for( i = 0;  netcard_portlist[ i ];  ++i ) {
                int  ioaddr = netcard_portlist[ i ];
                if( request_region( ioaddr, SBNI_IO_EXTENT, dev->name ) &&
                    sbni_probe1( dev, ioaddr, 0 ))
                        return 0;
        }

        return  -ENODEV;
}


static int __init
sbni_pci_probe( struct net_device  *dev )
{
        struct pci_dev  *pdev = NULL;

        while( (pdev = pci_get_class( PCI_CLASS_NETWORK_OTHER << 8, pdev ))
               != NULL ) {
                int  pci_irq_line;
                unsigned long  pci_ioaddr;

                if( pdev->vendor != SBNI_PCI_VENDOR &&
                    pdev->device != SBNI_PCI_DEVICE )
                        continue;

                pci_ioaddr = pci_resource_start( pdev, 0 );
                pci_irq_line = pdev->irq;

                /* Avoid already found cards from previous calls */
                if( !request_region( pci_ioaddr, SBNI_IO_EXTENT, dev->name ) ) {
                        if (pdev->subsystem_device != 2)
                                continue;

                        /* Dual adapter is present */
                        if (!request_region(pci_ioaddr += 4, SBNI_IO_EXTENT,
                                                        dev->name ) )
                                continue;
                }

                if (pci_irq_line <= 0 || pci_irq_line >= nr_irqs)
                        pr_warn(
"WARNING: The PCI BIOS assigned this PCI card to IRQ %d, which is unlikely to work!.\n"
"You should use the PCI BIOS setup to assign a valid IRQ line.\n",
                                pci_irq_line );

                /* avoiding re-enable dual adapters */
                if( (pci_ioaddr & 7) == 0  &&  pci_enable_device( pdev ) ) {
                        release_region( pci_ioaddr, SBNI_IO_EXTENT );
                        pci_dev_put( pdev );
                        return  -EIO;
                }
                if( sbni_probe1( dev, pci_ioaddr, pci_irq_line ) ) {
                        SET_NETDEV_DEV(dev, &pdev->dev);
                        /* not the best thing to do, but this is all messed up 
                           for hotplug systems anyway... */
                        pci_dev_put( pdev );
                        return  0;
                }
        }
        return  -ENODEV;
}


static struct net_device * __init
sbni_probe1( struct net_device  *dev,  unsigned long  ioaddr,  int  irq )
{
        struct net_local  *nl;

        if( sbni_card_probe( ioaddr ) ) {
                release_region( ioaddr, SBNI_IO_EXTENT );
                return NULL;
        }

        outb( 0, ioaddr + CSR0 );

        if( irq < 2 ) {
                unsigned long irq_mask;

                irq_mask = probe_irq_on();
                outb( EN_INT | TR_REQ, ioaddr + CSR0 );
                outb( PR_RES, ioaddr + CSR1 );
                mdelay(50);
                irq = probe_irq_off(irq_mask);
                outb( 0, ioaddr + CSR0 );

                if( !irq ) {
                        pr_err("%s: can't detect device irq!\n", dev->name);
                        release_region( ioaddr, SBNI_IO_EXTENT );
                        return NULL;
                }
        } else if( irq == 2 )
                irq = 9;

        dev->irq = irq;
        dev->base_addr = ioaddr;

        /* Fill in sbni-specific dev fields. */
        nl = netdev_priv(dev);
        if( !nl ) {
                pr_err("%s: unable to get memory!\n", dev->name);
                release_region( ioaddr, SBNI_IO_EXTENT );
                return NULL;
        }

        memset( nl, 0, sizeof(struct net_local) );
        spin_lock_init( &nl->lock );

        /* store MAC address (generate if that isn't known) */
        *(__be16 *)dev->dev_addr = htons( 0x00ff );
        *(__be32 *)(dev->dev_addr + 2) = htonl( 0x01000000 |
                ((mac[num] ?
                mac[num] :
                (u32)((long)netdev_priv(dev))) & 0x00ffffff));

        /* store link settings (speed, receive level ) */
        nl->maxframe  = DEFAULT_FRAME_LEN;
        nl->csr1.rate = baud[ num ];

        if( (nl->cur_rxl_index = rxl[ num ]) == -1 )
                /* autotune rxl */
                nl->cur_rxl_index = DEF_RXL,
                nl->delta_rxl = DEF_RXL_DELTA;
        else
                nl->delta_rxl = 0;
        nl->csr1.rxl  = rxl_tab[ nl->cur_rxl_index ];
        if( inb( ioaddr + CSR0 ) & 0x01 )
                nl->state |= FL_SLOW_MODE;

        pr_notice("%s: ioaddr %#lx, irq %d, MAC: 00:ff:01:%02x:%02x:%02x\n",
                  dev->name, dev->base_addr, dev->irq,
                  ((u8 *)dev->dev_addr)[3],
                  ((u8 *)dev->dev_addr)[4],
                  ((u8 *)dev->dev_addr)[5]);

        pr_notice("%s: speed %d",
                  dev->name,
                  ((nl->state & FL_SLOW_MODE) ? 500000 : 2000000)
                  / (1 << nl->csr1.rate));

        if( nl->delta_rxl == 0 )
                pr_cont(", receive level 0x%x (fixed)\n", nl->cur_rxl_index);
        else
                pr_cont(", receive level (auto)\n");

#ifdef CONFIG_SBNI_MULTILINE
        nl->master = dev;
        nl->link   = NULL;
#endif
   
        sbni_cards[ num++ ] = dev;
        return  dev;
}

/* -------------------------------------------------------------------------- */

#ifdef CONFIG_SBNI_MULTILINE

static netdev_tx_t
sbni_start_xmit( struct sk_buff  *skb,  struct net_device  *dev )
{
        struct net_device  *p;

        netif_stop_queue( dev );

        /* Looking for idle device in the list */
        for( p = dev;  p; ) {
                struct net_local  *nl = netdev_priv(p);
                spin_lock( &nl->lock );
                if( nl->tx_buf_p  ||  (nl->state & FL_LINE_DOWN) ) {
                        p = nl->link;
                        spin_unlock( &nl->lock );
                } else {
                        /* Idle dev is found */
                        prepare_to_send( skb, p );
                        spin_unlock( &nl->lock );
                        netif_start_queue( dev );
                        return NETDEV_TX_OK;
                }
        }

        return NETDEV_TX_BUSY;
}

#else   /* CONFIG_SBNI_MULTILINE */

static netdev_tx_t
sbni_start_xmit( struct sk_buff  *skb,  struct net_device  *dev )
{
        struct net_local  *nl  = netdev_priv(dev);

        netif_stop_queue( dev );
        spin_lock( &nl->lock );

        prepare_to_send( skb, dev );

        spin_unlock( &nl->lock );
        return NETDEV_TX_OK;
}

#endif  /* CONFIG_SBNI_MULTILINE */

/* -------------------------------------------------------------------------- */

/* interrupt handler */

/*
 *      SBNI12D-10, -11/ISA boards within "common interrupt" mode could not
 * be looked as two independent single-channel devices. Every channel seems
 * as Ethernet interface but interrupt handler must be common. Really, first
 * channel ("master") driver only registers the handler. In its struct net_local
 * it has got pointer to "slave" channel's struct net_local and handles that's
 * interrupts too.
 *      dev of successfully attached ISA SBNI boards is linked to list.
 * While next board driver is initialized, it scans this list. If one
 * has found dev with same irq and ioaddr different by 4 then it assumes
 * this board to be "master".
 */ 

static irqreturn_t
sbni_interrupt( int  irq,  void  *dev_id )
{
        struct net_device         *dev = dev_id;
        struct net_local  *nl  = netdev_priv(dev);
        int     repeat;

        spin_lock( &nl->lock );
        if( nl->second )
                spin_lock(&NET_LOCAL_LOCK(nl->second));

        do {
                repeat = 0;
                if( inb( dev->base_addr + CSR0 ) & (RC_RDY | TR_RDY) )
                        handle_channel( dev ),
                        repeat = 1;
                if( nl->second  &&      /* second channel present */
                    (inb( nl->second->base_addr+CSR0 ) & (RC_RDY | TR_RDY)) )
                        handle_channel( nl->second ),
                        repeat = 1;
        } while( repeat );

        if( nl->second )
                spin_unlock(&NET_LOCAL_LOCK(nl->second));
        spin_unlock( &nl->lock );
        return IRQ_HANDLED;
}


static void
handle_channel( struct net_device  *dev )
{
        struct net_local        *nl    = netdev_priv(dev);
        unsigned long           ioaddr = dev->base_addr;

        int  req_ans;
        unsigned char  csr0;

#ifdef CONFIG_SBNI_MULTILINE
        /* Lock the master device because we going to change its local data */
        if( nl->state & FL_SLAVE )
                spin_lock(&NET_LOCAL_LOCK(nl->master));
#endif

        outb( (inb( ioaddr + CSR0 ) & ~EN_INT) | TR_REQ, ioaddr + CSR0 );

        nl->timer_ticks = CHANGE_LEVEL_START_TICKS;
        for(;;) {
                csr0 = inb( ioaddr + CSR0 );
                if( ( csr0 & (RC_RDY | TR_RDY) ) == 0 )
                        break;

                req_ans = !(nl->state & FL_PREV_OK);

                if( csr0 & RC_RDY )
                        req_ans = recv_frame( dev );

                /*
                 * TR_RDY always equals 1 here because we have owned the marker,
                 * and we set TR_REQ when disabled interrupts
                 */
                csr0 = inb( ioaddr + CSR0 );
                if( !(csr0 & TR_RDY)  ||  (csr0 & RC_RDY) )
                        netdev_err(dev, "internal error!\n");

                /* if state & FL_NEED_RESEND != 0 then tx_frameno != 0 */
                if( req_ans  ||  nl->tx_frameno != 0 )
                        send_frame( dev );
                else
                        /* send marker without any data */
                        outb( inb( ioaddr + CSR0 ) & ~TR_REQ, ioaddr + CSR0 );
        }

        outb( inb( ioaddr + CSR0 ) | EN_INT, ioaddr + CSR0 );

#ifdef CONFIG_SBNI_MULTILINE
        if( nl->state & FL_SLAVE )
                spin_unlock(&NET_LOCAL_LOCK(nl->master));
#endif
}


/*
 * Routine returns 1 if it need to acknoweledge received frame.
 * Empty frame received without errors won't be acknoweledged.
 */

static int
recv_frame( struct net_device  *dev )
{
        struct net_local  *nl   = netdev_priv(dev);
        unsigned long  ioaddr   = dev->base_addr;

        u32  crc = CRC32_INITIAL;

        unsigned  framelen = 0, frameno, ack;
        unsigned  is_first, frame_ok = 0;

        if( check_fhdr( ioaddr, &framelen, &frameno, &ack, &is_first, &crc ) ) {
                frame_ok = framelen > 4
                        ?  upload_data( dev, framelen, frameno, is_first, crc )
                        :  skip_tail( ioaddr, framelen, crc );
                if( frame_ok )
                        interpret_ack( dev, ack );
        }

        outb( inb( ioaddr + CSR0 ) ^ CT_ZER, ioaddr + CSR0 );
        if( frame_ok ) {
                nl->state |= FL_PREV_OK;
                if( framelen > 4 )
                        nl->in_stats.all_rx_number++;
        } else
                nl->state &= ~FL_PREV_OK,
                change_level( dev ),
                nl->in_stats.all_rx_number++,
                nl->in_stats.bad_rx_number++;

        return  !frame_ok  ||  framelen > 4;
}


static void
send_frame( struct net_device  *dev )
{
        struct net_local  *nl    = netdev_priv(dev);

        u32  crc = CRC32_INITIAL;

        if( nl->state & FL_NEED_RESEND ) {

                /* if frame was sended but not ACK'ed - resend it */
                if( nl->trans_errors ) {
                        --nl->trans_errors;
                        if( nl->framelen != 0 )
                                nl->in_stats.resend_tx_number++;
                } else {
                        /* cannot xmit with many attempts */
#ifdef CONFIG_SBNI_MULTILINE
                        if( (nl->state & FL_SLAVE)  ||  nl->link )
#endif
                        nl->state |= FL_LINE_DOWN;
                        drop_xmit_queue( dev );
                        goto  do_send;
                }
        } else
                nl->trans_errors = TR_ERROR_COUNT;

        send_frame_header( dev, &crc );
        nl->state |= FL_NEED_RESEND;
        /*
         * FL_NEED_RESEND will be cleared after ACK, but if empty
         * frame sended then in prepare_to_send next frame
         */


        if( nl->framelen ) {
                download_data( dev, &crc );
                nl->in_stats.all_tx_number++;
                nl->state |= FL_WAIT_ACK;
        }

        outsb( dev->base_addr + DAT, (u8 *)&crc, sizeof crc );

do_send:
        outb( inb( dev->base_addr + CSR0 ) & ~TR_REQ, dev->base_addr + CSR0 );

        if( nl->tx_frameno )
                /* next frame exists - we request card to send it */
                outb( inb( dev->base_addr + CSR0 ) | TR_REQ,
                      dev->base_addr + CSR0 );
}


/*
 * Write the frame data into adapter's buffer memory, and calculate CRC.
 * Do padding if necessary.
 */

static void
download_data( struct net_device  *dev,  u32  *crc_p )
{
        struct net_local  *nl    = netdev_priv(dev);
        struct sk_buff    *skb   = nl->tx_buf_p;

        unsigned  len = min_t(unsigned int, skb->len - nl->outpos, nl->framelen);

        outsb( dev->base_addr + DAT, skb->data + nl->outpos, len );
        *crc_p = calc_crc32( *crc_p, skb->data + nl->outpos, len );

        /* if packet too short we should write some more bytes to pad */
        for( len = nl->framelen - len;  len--; )
                outb( 0, dev->base_addr + DAT ),
                *crc_p = CRC32( 0, *crc_p );
}


static int
upload_data( struct net_device  *dev,  unsigned  framelen,  unsigned  frameno,
             unsigned  is_first,  u32  crc )
{
        struct net_local  *nl = netdev_priv(dev);

        int  frame_ok;

        if( is_first )
                nl->wait_frameno = frameno,
                nl->inppos = 0;

        if( nl->wait_frameno == frameno ) {

                if( nl->inppos + framelen  <=  ETHER_MAX_LEN )
                        frame_ok = append_frame_to_pkt( dev, framelen, crc );

                /*
                 * if CRC is right but framelen incorrect then transmitter
                 * error was occurred... drop entire packet
                 */
                else if( (frame_ok = skip_tail( dev->base_addr, framelen, crc ))
                         != 0 )
                        nl->wait_frameno = 0,
                        nl->inppos = 0,
#ifdef CONFIG_SBNI_MULTILINE
                        nl->master->stats.rx_errors++,
                        nl->master->stats.rx_missed_errors++;
#else
                        dev->stats.rx_errors++,
                        dev->stats.rx_missed_errors++;
#endif
                        /* now skip all frames until is_first != 0 */
        } else
                frame_ok = skip_tail( dev->base_addr, framelen, crc );

        if( is_first  &&  !frame_ok )
                /*
                 * Frame has been broken, but we had already stored
                 * is_first... Drop entire packet.
                 */
                nl->wait_frameno = 0,
#ifdef CONFIG_SBNI_MULTILINE
                nl->master->stats.rx_errors++,
                nl->master->stats.rx_crc_errors++;
#else
                dev->stats.rx_errors++,
                dev->stats.rx_crc_errors++;
#endif

        return  frame_ok;
}


static inline void
send_complete( struct net_device *dev )
{
        struct net_local  *nl = netdev_priv(dev);

#ifdef CONFIG_SBNI_MULTILINE
        nl->master->stats.tx_packets++;
        nl->master->stats.tx_bytes += nl->tx_buf_p->len;
#else
        dev->stats.tx_packets++;
        dev->stats.tx_bytes += nl->tx_buf_p->len;
#endif
        dev_kfree_skb_irq( nl->tx_buf_p );

        nl->tx_buf_p = NULL;

        nl->outpos = 0;
        nl->state &= ~(FL_WAIT_ACK | FL_NEED_RESEND);
        nl->framelen   = 0;
}


static void
interpret_ack( struct net_device  *dev,  unsigned  ack )
{
        struct net_local  *nl = netdev_priv(dev);

        if( ack == FRAME_SENT_OK ) {
                nl->state &= ~FL_NEED_RESEND;

                if( nl->state & FL_WAIT_ACK ) {
                        nl->outpos += nl->framelen;

                        if( --nl->tx_frameno )
                                nl->framelen = min_t(unsigned int,
                                                   nl->maxframe,
                                                   nl->tx_buf_p->len - nl->outpos);
                        else
                                send_complete( dev ),
#ifdef CONFIG_SBNI_MULTILINE
                                netif_wake_queue( nl->master );
#else
                                netif_wake_queue( dev );
#endif
                }
        }

        nl->state &= ~FL_WAIT_ACK;
}


/*
 * Glue received frame with previous fragments of packet.
 * Indicate packet when last frame would be accepted.
 */

static int
append_frame_to_pkt( struct net_device  *dev,  unsigned  framelen,  u32  crc )
{
        struct net_local  *nl = netdev_priv(dev);

        u8  *p;

        if( nl->inppos + framelen  >  ETHER_MAX_LEN )
                return  0;

        if( !nl->rx_buf_p  &&  !(nl->rx_buf_p = get_rx_buf( dev )) )
                return  0;

        p = nl->rx_buf_p->data + nl->inppos;
        insb( dev->base_addr + DAT, p, framelen );
        if( calc_crc32( crc, p, framelen ) != CRC32_REMAINDER )
                return  0;

        nl->inppos += framelen - 4;
        if( --nl->wait_frameno == 0 )           /* last frame received */
                indicate_pkt( dev );

        return  1;
}


/*
 * Prepare to start output on adapter.
 * Transmitter will be actually activated when marker is accepted.
 */

static void
prepare_to_send( struct sk_buff  *skb,  struct net_device  *dev )
{
        struct net_local  *nl = netdev_priv(dev);

        unsigned int  len;

        /* nl->tx_buf_p == NULL here! */
        if( nl->tx_buf_p )
                netdev_err(dev, "memory leak!\n");

        nl->outpos = 0;
        nl->state &= ~(FL_WAIT_ACK | FL_NEED_RESEND);

        len = skb->len;
        if( len < SBNI_MIN_LEN )
                len = SBNI_MIN_LEN;

        nl->tx_buf_p    = skb;
        nl->tx_frameno  = DIV_ROUND_UP(len, nl->maxframe);
        nl->framelen    = len < nl->maxframe  ?  len  :  nl->maxframe;

        outb( inb( dev->base_addr + CSR0 ) | TR_REQ,  dev->base_addr + CSR0 );
#ifdef CONFIG_SBNI_MULTILINE
        netif_trans_update(nl->master);
#else
        netif_trans_update(dev);
#endif
}


static void
drop_xmit_queue( struct net_device  *dev )
{
        struct net_local  *nl = netdev_priv(dev);

        if( nl->tx_buf_p )
                dev_kfree_skb_any( nl->tx_buf_p ),
                nl->tx_buf_p = NULL,
#ifdef CONFIG_SBNI_MULTILINE
                nl->master->stats.tx_errors++,
                nl->master->stats.tx_carrier_errors++;
#else
                dev->stats.tx_errors++,
                dev->stats.tx_carrier_errors++;
#endif

        nl->tx_frameno  = 0;
        nl->framelen    = 0;
        nl->outpos      = 0;
        nl->state &= ~(FL_WAIT_ACK | FL_NEED_RESEND);
#ifdef CONFIG_SBNI_MULTILINE
        netif_start_queue( nl->master );
        netif_trans_update(nl->master);
#else
        netif_start_queue( dev );
        netif_trans_update(dev);
#endif
}


static void
send_frame_header( struct net_device  *dev,  u32  *crc_p )
{
        struct net_local  *nl  = netdev_priv(dev);

        u32  crc = *crc_p;
        u32  len_field = nl->framelen + 6;      /* CRC + frameno + reserved */
        u8   value;

        if( nl->state & FL_NEED_RESEND )
                len_field |= FRAME_RETRY;       /* non-first attempt... */

        if( nl->outpos == 0 )
                len_field |= FRAME_FIRST;

        len_field |= (nl->state & FL_PREV_OK) ? FRAME_SENT_OK : FRAME_SENT_BAD;
        outb( SBNI_SIG, dev->base_addr + DAT );

        value = (u8) len_field;
        outb( value, dev->base_addr + DAT );
        crc = CRC32( value, crc );
        value = (u8) (len_field >> 8);
        outb( value, dev->base_addr + DAT );
        crc = CRC32( value, crc );

        outb( nl->tx_frameno, dev->base_addr + DAT );
        crc = CRC32( nl->tx_frameno, crc );
        outb( 0, dev->base_addr + DAT );
        crc = CRC32( 0, crc );
        *crc_p = crc;
}


/*
 * if frame tail not needed (incorrect number or received twice),
 * it won't store, but CRC will be calculated
 */

static int
skip_tail( unsigned int  ioaddr,  unsigned int  tail_len,  u32 crc )
{
        while( tail_len-- )
                crc = CRC32( inb( ioaddr + DAT ), crc );

        return  crc == CRC32_REMAINDER;
}


/*
 * Preliminary checks if frame header is correct, calculates its CRC
 * and split it to simple fields
 */

static int
check_fhdr( u32  ioaddr,  u32  *framelen,  u32  *frameno,  u32  *ack,
            u32  *is_first,  u32  *crc_p )
{
        u32  crc = *crc_p;
        u8   value;

        if( inb( ioaddr + DAT ) != SBNI_SIG )
                return  0;

        value = inb( ioaddr + DAT );
        *framelen = (u32)value;
        crc = CRC32( value, crc );
        value = inb( ioaddr + DAT );
        *framelen |= ((u32)value) << 8;
        crc = CRC32( value, crc );

        *ack = *framelen & FRAME_ACK_MASK;
        *is_first = (*framelen & FRAME_FIRST) != 0;

        if( (*framelen &= FRAME_LEN_MASK) < 6 ||
            *framelen > SBNI_MAX_FRAME - 3 )
                return  0;

        value = inb( ioaddr + DAT );
        *frameno = (u32)value;
        crc = CRC32( value, crc );

        crc = CRC32( inb( ioaddr + DAT ), crc );        /* reserved byte */
        *framelen -= 2;

        *crc_p = crc;
        return  1;
}


static struct sk_buff *
get_rx_buf( struct net_device  *dev )
{
        /* +2 is to compensate for the alignment fixup below */
        struct sk_buff  *skb = dev_alloc_skb( ETHER_MAX_LEN + 2 );
        if( !skb )
                return  NULL;

        skb_reserve( skb, 2 );          /* Align IP on longword boundaries */
        return  skb;
}

static void
indicate_pkt( struct net_device  *dev )
{
        struct net_local  *nl  = netdev_priv(dev);
        struct sk_buff    *skb = nl->rx_buf_p;

        skb_put( skb, nl->inppos );

#ifdef CONFIG_SBNI_MULTILINE
        skb->protocol = eth_type_trans( skb, nl->master );
        netif_rx( skb );
        ++nl->master->stats.rx_packets;
        nl->master->stats.rx_bytes += nl->inppos;
#else
        skb->protocol = eth_type_trans( skb, dev );
        netif_rx( skb );
        ++dev->stats.rx_packets;
        dev->stats.rx_bytes += nl->inppos;
#endif
        nl->rx_buf_p = NULL;    /* protocol driver will clear this sk_buff */
}


/* -------------------------------------------------------------------------- */

/*
 * Routine checks periodically wire activity and regenerates marker if
 * connect was inactive for a long time.
 */

static void
sbni_watchdog( unsigned long  arg )
{
        struct net_device  *dev = (struct net_device *) arg;
        struct net_local   *nl  = netdev_priv(dev);
        struct timer_list  *w   = &nl->watchdog; 
        unsigned long      flags;
        unsigned char      csr0;

        spin_lock_irqsave( &nl->lock, flags );

        csr0 = inb( dev->base_addr + CSR0 );
        if( csr0 & RC_CHK ) {

                if( nl->timer_ticks ) {
                        if( csr0 & (RC_RDY | BU_EMP) )
                                /* receiving not active */
                                nl->timer_ticks--;
                } else {
                        nl->in_stats.timeout_number++;
                        if( nl->delta_rxl )
                                timeout_change_level( dev );

                        outb( *(u_char *)&nl->csr1 | PR_RES,
                              dev->base_addr + CSR1 );
                        csr0 = inb( dev->base_addr + CSR0 );
                }
        } else
                nl->state &= ~FL_LINE_DOWN;

        outb( csr0 | RC_CHK, dev->base_addr + CSR0 ); 

        init_timer( w );
        w->expires      = jiffies + SBNI_TIMEOUT;
        w->data         = arg;
        w->function     = sbni_watchdog;
        add_timer( w );

        spin_unlock_irqrestore( &nl->lock, flags );
}


static unsigned char  rxl_tab[] = {
        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x08,
        0x0a, 0x0c, 0x0f, 0x16, 0x18, 0x1a, 0x1c, 0x1f
};

#define SIZE_OF_TIMEOUT_RXL_TAB 4
static unsigned char  timeout_rxl_tab[] = {
        0x03, 0x05, 0x08, 0x0b
};

/* -------------------------------------------------------------------------- */

static void
card_start( struct net_device  *dev )
{
        struct net_local  *nl = netdev_priv(dev);

        nl->timer_ticks = CHANGE_LEVEL_START_TICKS;
        nl->state &= ~(FL_WAIT_ACK | FL_NEED_RESEND);
        nl->state |= FL_PREV_OK;

        nl->inppos = nl->outpos = 0;
        nl->wait_frameno = 0;
        nl->tx_frameno   = 0;
        nl->framelen     = 0;

        outb( *(u_char *)&nl->csr1 | PR_RES, dev->base_addr + CSR1 );
        outb( EN_INT, dev->base_addr + CSR0 );
}

/* -------------------------------------------------------------------------- */

/* Receive level auto-selection */

static void
change_level( struct net_device  *dev )
{
        struct net_local  *nl = netdev_priv(dev);

        if( nl->delta_rxl == 0 )        /* do not auto-negotiate RxL */
                return;

        if( nl->cur_rxl_index == 0 )
                nl->delta_rxl = 1;
        else if( nl->cur_rxl_index == 15 )
                nl->delta_rxl = -1;
        else if( nl->cur_rxl_rcvd < nl->prev_rxl_rcvd )
                nl->delta_rxl = -nl->delta_rxl;

        nl->csr1.rxl = rxl_tab[ nl->cur_rxl_index += nl->delta_rxl ];
        inb( dev->base_addr + CSR0 );   /* needs for PCI cards */
        outb( *(u8 *)&nl->csr1, dev->base_addr + CSR1 );

        nl->prev_rxl_rcvd = nl->cur_rxl_rcvd;
        nl->cur_rxl_rcvd  = 0;
}


static void
timeout_change_level( struct net_device  *dev )
{
        struct net_local  *nl = netdev_priv(dev);

        nl->cur_rxl_index = timeout_rxl_tab[ nl->timeout_rxl ];
        if( ++nl->timeout_rxl >= 4 )
                nl->timeout_rxl = 0;

        nl->csr1.rxl = rxl_tab[ nl->cur_rxl_index ];
        inb( dev->base_addr + CSR0 );
        outb( *(unsigned char *)&nl->csr1, dev->base_addr + CSR1 );

        nl->prev_rxl_rcvd = nl->cur_rxl_rcvd;
        nl->cur_rxl_rcvd  = 0;
}

/* -------------------------------------------------------------------------- */

/*
 *      Open/initialize the board. 
 */

static int
sbni_open( struct net_device  *dev )
{
        struct net_local        *nl = netdev_priv(dev);
        struct timer_list       *w  = &nl->watchdog;

        /*
         * For double ISA adapters within "common irq" mode, we have to
         * determine whether primary or secondary channel is initialized,
         * and set the irq handler only in first case.
         */
        if( dev->base_addr < 0x400 ) {          /* ISA only */
                struct net_device  **p = sbni_cards;
                for( ;  *p  &&  p < sbni_cards + SBNI_MAX_NUM_CARDS;  ++p )
                        if( (*p)->irq == dev->irq &&
                            ((*p)->base_addr == dev->base_addr + 4 ||
                             (*p)->base_addr == dev->base_addr - 4) &&
                            (*p)->flags & IFF_UP ) {

                                ((struct net_local *) (netdev_priv(*p)))
                                        ->second = dev;
                                netdev_notice(dev, "using shared irq with %s\n",
                                              (*p)->name);
                                nl->state |= FL_SECONDARY;
                                goto  handler_attached;
                        }
        }

        if( request_irq(dev->irq, sbni_interrupt, IRQF_SHARED, dev->name, dev) ) {
                netdev_err(dev, "unable to get IRQ %d\n", dev->irq);
                return  -EAGAIN;
        }

handler_attached:

        spin_lock( &nl->lock );
        memset( &dev->stats, 0, sizeof(struct net_device_stats) );
        memset( &nl->in_stats, 0, sizeof(struct sbni_in_stats) );

        card_start( dev );

        netif_start_queue( dev );

        /* set timer watchdog */
        init_timer( w );
        w->expires      = jiffies + SBNI_TIMEOUT;
        w->data         = (unsigned long) dev;
        w->function     = sbni_watchdog;
        add_timer( w );
   
        spin_unlock( &nl->lock );
        return 0;
}


static int
sbni_close( struct net_device  *dev )
{
        struct net_local  *nl = netdev_priv(dev);

        if( nl->second  &&  nl->second->flags & IFF_UP ) {
                netdev_notice(dev, "Secondary channel (%s) is active!\n",
                              nl->second->name);
                return  -EBUSY;
        }

#ifdef CONFIG_SBNI_MULTILINE
        if( nl->state & FL_SLAVE )
                emancipate( dev );
        else
                while( nl->link )       /* it's master device! */
                        emancipate( nl->link );
#endif

        spin_lock( &nl->lock );

        nl->second = NULL;
        drop_xmit_queue( dev ); 
        netif_stop_queue( dev );
   
        del_timer( &nl->watchdog );

        outb( 0, dev->base_addr + CSR0 );

        if( !(nl->state & FL_SECONDARY) )
                free_irq( dev->irq, dev );
        nl->state &= FL_SECONDARY;

        spin_unlock( &nl->lock );
        return 0;
}


/*
        Valid combinations in CSR0 (for probing):

        VALID_DECODER   0000,0011,1011,1010

                                        ; 0   ; -
                                TR_REQ  ; 1   ; +
                        TR_RDY          ; 2   ; -
                        TR_RDY  TR_REQ  ; 3   ; +
                BU_EMP                  ; 4   ; +
                BU_EMP          TR_REQ  ; 5   ; +
                BU_EMP  TR_RDY          ; 6   ; -
                BU_EMP  TR_RDY  TR_REQ  ; 7   ; +
        RC_RDY                          ; 8   ; +
        RC_RDY                  TR_REQ  ; 9   ; +
        RC_RDY          TR_RDY          ; 10  ; -
        RC_RDY          TR_RDY  TR_REQ  ; 11  ; -
        RC_RDY  BU_EMP                  ; 12  ; -
        RC_RDY  BU_EMP          TR_REQ  ; 13  ; -
        RC_RDY  BU_EMP  TR_RDY          ; 14  ; -
        RC_RDY  BU_EMP  TR_RDY  TR_REQ  ; 15  ; -
*/

#define VALID_DECODER (2 + 8 + 0x10 + 0x20 + 0x80 + 0x100 + 0x200)


static int
sbni_card_probe( unsigned long  ioaddr )
{
        unsigned char  csr0;

        csr0 = inb( ioaddr + CSR0 );
        if( csr0 != 0xff  &&  csr0 != 0x00 ) {
                csr0 &= ~EN_INT;
                if( csr0 & BU_EMP )
                        csr0 |= EN_INT;
      
                if( VALID_DECODER & (1 << (csr0 >> 4)) )
                        return  0;
        }
   
        return  -ENODEV;
}

/* -------------------------------------------------------------------------- */

static int
sbni_ioctl( struct net_device  *dev,  struct ifreq  *ifr,  int  cmd )
{
        struct net_local  *nl = netdev_priv(dev);
        struct sbni_flags  flags;
        int  error = 0;

#ifdef CONFIG_SBNI_MULTILINE
        struct net_device  *slave_dev;
        char  slave_name[ 8 ];
#endif
  
        switch( cmd ) {
        case  SIOCDEVGETINSTATS :
                if (copy_to_user( ifr->ifr_data, &nl->in_stats,
                                        sizeof(struct sbni_in_stats) ))
                        error = -EFAULT;
                break;

        case  SIOCDEVRESINSTATS :
                if (!capable(CAP_NET_ADMIN))
                        return  -EPERM;
                memset( &nl->in_stats, 0, sizeof(struct sbni_in_stats) );
                break;

        case  SIOCDEVGHWSTATE :
                flags.mac_addr  = *(u32 *)(dev->dev_addr + 3);
                flags.rate      = nl->csr1.rate;
                flags.slow_mode = (nl->state & FL_SLOW_MODE) != 0;
                flags.rxl       = nl->cur_rxl_index;
                flags.fixed_rxl = nl->delta_rxl == 0;

                if (copy_to_user( ifr->ifr_data, &flags, sizeof flags ))
                        error = -EFAULT;
                break;

        case  SIOCDEVSHWSTATE :
                if (!capable(CAP_NET_ADMIN))
                        return  -EPERM;

                spin_lock( &nl->lock );
                flags = *(struct sbni_flags*) &ifr->ifr_ifru;
                if( flags.fixed_rxl )
                        nl->delta_rxl = 0,
                        nl->cur_rxl_index = flags.rxl;
                else
                        nl->delta_rxl = DEF_RXL_DELTA,
                        nl->cur_rxl_index = DEF_RXL;

                nl->csr1.rxl = rxl_tab[ nl->cur_rxl_index ];
                nl->csr1.rate = flags.rate;
                outb( *(u8 *)&nl->csr1 | PR_RES, dev->base_addr + CSR1 );
                spin_unlock( &nl->lock );
                break;

#ifdef CONFIG_SBNI_MULTILINE

        case  SIOCDEVENSLAVE :
                if (!capable(CAP_NET_ADMIN))
                        return  -EPERM;

                if (copy_from_user( slave_name, ifr->ifr_data, sizeof slave_name ))
                        return -EFAULT;
                slave_dev = dev_get_by_name(&init_net, slave_name );
                if( !slave_dev  ||  !(slave_dev->flags & IFF_UP) ) {
                        netdev_err(dev, "trying to enslave non-active device %s\n",
                                   slave_name);
                        if (slave_dev)
                                dev_put(slave_dev);
                        return  -EPERM;
                }

                return  enslave( dev, slave_dev );

        case  SIOCDEVEMANSIPATE :
                if (!capable(CAP_NET_ADMIN))
                        return  -EPERM;

                return  emancipate( dev );

#endif  /* CONFIG_SBNI_MULTILINE */

        default :
                return  -EOPNOTSUPP;
        }

        return  error;
}


#ifdef CONFIG_SBNI_MULTILINE

static int
enslave( struct net_device  *dev,  struct net_device  *slave_dev )
{
        struct net_local  *nl  = netdev_priv(dev);
        struct net_local  *snl = netdev_priv(slave_dev);

        if( nl->state & FL_SLAVE )      /* This isn't master or free device */
                return  -EBUSY;

        if( snl->state & FL_SLAVE )     /* That was already enslaved */
                return  -EBUSY;

        spin_lock( &nl->lock );
        spin_lock( &snl->lock );

        /* append to list */
        snl->link = nl->link;
        nl->link  = slave_dev;
        snl->master = dev;
        snl->state |= FL_SLAVE;

        /* Summary statistics of MultiLine operation will be stored
           in master's counters */
        memset( &slave_dev->stats, 0, sizeof(struct net_device_stats) );
        netif_stop_queue( slave_dev );
        netif_wake_queue( dev );        /* Now we are able to transmit */

        spin_unlock( &snl->lock );
        spin_unlock( &nl->lock );
        netdev_notice(dev, "slave device (%s) attached\n", slave_dev->name);
        return  0;
}


static int
emancipate( struct net_device  *dev )
{
        struct net_local   *snl = netdev_priv(dev);
        struct net_device  *p   = snl->master;
        struct net_local   *nl  = netdev_priv(p);

        if( !(snl->state & FL_SLAVE) )
                return  -EINVAL;

        spin_lock( &nl->lock );
        spin_lock( &snl->lock );
        drop_xmit_queue( dev );

        /* exclude from list */
        for(;;) {       /* must be in list */
                struct net_local  *t = netdev_priv(p);
                if( t->link == dev ) {
                        t->link = snl->link;
                        break;
                }
                p = t->link;
        }

        snl->link = NULL;
        snl->master = dev;
        snl->state &= ~FL_SLAVE;

        netif_start_queue( dev );

        spin_unlock( &snl->lock );
        spin_unlock( &nl->lock );

        dev_put( dev );
        return  0;
}

#endif

static void
set_multicast_list( struct net_device  *dev )
{
        return;         /* sbni always operate in promiscuos mode */
}


#ifdef MODULE
module_param_array(io, int, NULL, 0);
module_param_array(irq, int, NULL, 0);
module_param_array(baud, int, NULL, 0);
module_param_array(rxl, int, NULL, 0);
module_param_array(mac, int, NULL, 0);
module_param(skip_pci_probe, bool, 0);

MODULE_LICENSE("GPL");


int __init init_module( void )
{
        struct net_device  *dev;
        int err;

        while( num < SBNI_MAX_NUM_CARDS ) {
                dev = alloc_netdev(sizeof(struct net_local), "sbni%d",
                                   NET_NAME_UNKNOWN, sbni_devsetup);
                if( !dev)
                        break;

                sprintf( dev->name, "sbni%d", num );

                err = sbni_init(dev);
                if (err) {
                        free_netdev(dev);
                        break;
                }

                if( register_netdev( dev ) ) {
                        release_region( dev->base_addr, SBNI_IO_EXTENT );
                        free_netdev( dev );
                        break;
                }
        }

        return  *sbni_cards  ?  0  :  -ENODEV;
}

void
cleanup_module(void)
{
        int i;

        for (i = 0;  i < SBNI_MAX_NUM_CARDS;  ++i) {
                struct net_device *dev = sbni_cards[i];
                if (dev != NULL) {
                        unregister_netdev(dev);
                        release_region(dev->base_addr, SBNI_IO_EXTENT);
                        free_netdev(dev);
                }
        }
}

#else   /* MODULE */

static int __init
sbni_setup( char  *p )
{
        int  n, parm;

        if( *p++ != '(' )
                goto  bad_param;

        for( n = 0, parm = 0;  *p  &&  n < 8; ) {
                (*dest[ parm ])[ n ] = simple_strtol( p, &p, 0 );
                if( !*p  ||  *p == ')' )
                        return 1;
                if( *p == ';' )
                        ++p, ++n, parm = 0;
                else if( *p++ != ',' )
                        break;
                else
                        if( ++parm >= 5 )
                                break;
        }
bad_param:
        pr_err("Error in sbni kernel parameter!\n");
        return 0;
}

__setup( "sbni=", sbni_setup );

#endif  /* MODULE */

/* -------------------------------------------------------------------------- */

static u32
calc_crc32( u32  crc,  u8  *p,  u32  len )
{
        while( len-- )
                crc = CRC32( *p++, crc );

        return  crc;
}

static u32  crc32tab[] __attribute__ ((aligned(8))) = {
        0xD202EF8D,  0xA505DF1B,  0x3C0C8EA1,  0x4B0BBE37,
        0xD56F2B94,  0xA2681B02,  0x3B614AB8,  0x4C667A2E,
        0xDCD967BF,  0xABDE5729,  0x32D70693,  0x45D03605,
        0xDBB4A3A6,  0xACB39330,  0x35BAC28A,  0x42BDF21C,
        0xCFB5FFE9,  0xB8B2CF7F,  0x21BB9EC5,  0x56BCAE53,
        0xC8D83BF0,  0xBFDF0B66,  0x26D65ADC,  0x51D16A4A,
        0xC16E77DB,  0xB669474D,  0x2F6016F7,  0x58672661,
        0xC603B3C2,  0xB1048354,  0x280DD2EE,  0x5F0AE278,
        0xE96CCF45,  0x9E6BFFD3,  0x0762AE69,  0x70659EFF,
        0xEE010B5C,  0x99063BCA,  0x000F6A70,  0x77085AE6,
        0xE7B74777,  0x90B077E1,  0x09B9265B,  0x7EBE16CD,
        0xE0DA836E,  0x97DDB3F8,  0x0ED4E242,  0x79D3D2D4,
        0xF4DBDF21,  0x83DCEFB7,  0x1AD5BE0D,  0x6DD28E9B,
        0xF3B61B38,  0x84B12BAE,  0x1DB87A14,  0x6ABF4A82,
        0xFA005713,  0x8D076785,  0x140E363F,  0x630906A9,
        0xFD6D930A,  0x8A6AA39C,  0x1363F226,  0x6464C2B0,
        0xA4DEAE1D,  0xD3D99E8B,  0x4AD0CF31,  0x3DD7FFA7,
        0xA3B36A04,  0xD4B45A92,  0x4DBD0B28,  0x3ABA3BBE,
        0xAA05262F,  0xDD0216B9,  0x440B4703,  0x330C7795,
        0xAD68E236,  0xDA6FD2A0,  0x4366831A,  0x3461B38C,
        0xB969BE79,  0xCE6E8EEF,  0x5767DF55,  0x2060EFC3,
        0xBE047A60,  0xC9034AF6,  0x500A1B4C,  0x270D2BDA,
        0xB7B2364B,  0xC0B506DD,  0x59BC5767,  0x2EBB67F1,
        0xB0DFF252,  0xC7D8C2C4,  0x5ED1937E,  0x29D6A3E8,
        0x9FB08ED5,  0xE8B7BE43,  0x71BEEFF9,  0x06B9DF6F,
        0x98DD4ACC,  0xEFDA7A5A,  0x76D32BE0,  0x01D41B76,
        0x916B06E7,  0xE66C3671,  0x7F6567CB,  0x0862575D,
        0x9606C2FE,  0xE101F268,  0x7808A3D2,  0x0F0F9344,
        0x82079EB1,  0xF500AE27,  0x6C09FF9D,  0x1B0ECF0B,
        0x856A5AA8,  0xF26D6A3E,  0x6B643B84,  0x1C630B12,
        0x8CDC1683,  0xFBDB2615,  0x62D277AF,  0x15D54739,
        0x8BB1D29A,  0xFCB6E20C,  0x65BFB3B6,  0x12B88320,
        0x3FBA6CAD,  0x48BD5C3B,  0xD1B40D81,  0xA6B33D17,
        0x38D7A8B4,  0x4FD09822,  0xD6D9C998,  0xA1DEF90E,
        0x3161E49F,  0x4666D409,  0xDF6F85B3,  0xA868B525,
        0x360C2086,  0x410B1010,  0xD80241AA,  0xAF05713C,
        0x220D7CC9,  0x550A4C5F,  0xCC031DE5,  0xBB042D73,
        0x2560B8D0,  0x52678846,  0xCB6ED9FC,  0xBC69E96A,
        0x2CD6F4FB,  0x5BD1C46D,  0xC2D895D7,  0xB5DFA541,
        0x2BBB30E2,  0x5CBC0074,  0xC5B551CE,  0xB2B26158,
        0x04D44C65,  0x73D37CF3,  0xEADA2D49,  0x9DDD1DDF,
        0x03B9887C,  0x74BEB8EA,  0xEDB7E950,  0x9AB0D9C6,
        0x0A0FC457,  0x7D08F4C1,  0xE401A57B,  0x930695ED,
        0x0D62004E,  0x7A6530D8,  0xE36C6162,  0x946B51F4,
        0x19635C01,  0x6E646C97,  0xF76D3D2D,  0x806A0DBB,
        0x1E0E9818,  0x6909A88E,  0xF000F934,  0x8707C9A2,
        0x17B8D433,  0x60BFE4A5,  0xF9B6B51F,  0x8EB18589,
        0x10D5102A,  0x67D220BC,  0xFEDB7106,  0x89DC4190,
        0x49662D3D,  0x3E611DAB,  0xA7684C11,  0xD06F7C87,
        0x4E0BE924,  0x390CD9B2,  0xA0058808,  0xD702B89E,
        0x47BDA50F,  0x30BA9599,  0xA9B3C423,  0xDEB4F4B5,
        0x40D06116,  0x37D75180,  0xAEDE003A,  0xD9D930AC,
        0x54D13D59,  0x23D60DCF,  0xBADF5C75,  0xCDD86CE3,
        0x53BCF940,  0x24BBC9D6,  0xBDB2986C,  0xCAB5A8FA,
        0x5A0AB56B,  0x2D0D85FD,  0xB404D447,  0xC303E4D1,
        0x5D677172,  0x2A6041E4,  0xB369105E,  0xC46E20C8,
        0x72080DF5,  0x050F3D63,  0x9C066CD9,  0xEB015C4F,
        0x7565C9EC,  0x0262F97A,  0x9B6BA8C0,  0xEC6C9856,
        0x7CD385C7,  0x0BD4B551,  0x92DDE4EB,  0xE5DAD47D,
        0x7BBE41DE,  0x0CB97148,  0x95B020F2,  0xE2B71064,
        0x6FBF1D91,  0x18B82D07,  0x81B17CBD,  0xF6B64C2B,
        0x68D2D988,  0x1FD5E91E,  0x86DCB8A4,  0xF1DB8832,
        0x616495A3,  0x1663A535,  0x8F6AF48F,  0xF86DC419,
        0x660951BA,  0x110E612C,  0x88073096,  0xFF000000
};