/*	$Id: com20020.c,v 1.6 1997/11/09 11:04:58 mj Exp $

        Written 1997 by David Woodhouse <dwmw2@cam.ac.uk>

	Derived from the original arcnet.c,
	Written 1994-1996 by Avery Pennarun,
	which was in turn derived from skeleton.c by Donald Becker.

	**********************

	The original copyright of skeleton.c was as follows:

	skeleton.c Written 1993 by Donald Becker.
	Copyright 1993 United States Government as represented by the
        Director, National Security Agency.  This software may only be used
        and distributed according to the terms of the GNU Public License as
        modified by SRC, incorporated herein by reference.

	**********************

	For more details, see drivers/net/arcnet.c

	**********************
*/


#include <linux/module.h>
#include <linux/version.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/malloc.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/if_arcnet.h>
#include <linux/arcdevice.h>

#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/io.h>
#include <asm/dma.h>

#include <net/arp.h>


/* Internal function declarations */

static int arc20020_probe(struct net_device *dev);
static void arc20020_rx(struct net_device *dev,int recbuf);
static int arc20020_found(struct net_device *dev,int ioaddr,int airq);
static void arc20020_inthandler (struct net_device *dev);
static int arc20020_reset (struct net_device *dev, int reset_delay);
static void arc20020_setmask (struct net_device *dev, u_char mask);
static void arc20020_command (struct net_device *dev, u_char command);
static u_char arc20020_status (struct net_device *dev);
static void arc20020_en_dis_able_TX (struct net_device *dev, int enable); 
static void arc20020_prepare_tx(struct net_device *dev,u_char *hdr,int hdrlen,
       		      char *data,int length,int daddr,int exceptA, int offset);
static  void arc20020_openclose(int open);
static void arc20020_set_mc_list(struct net_device *dev);
static u_char get_buffer_byte (struct net_device *dev, unsigned offset);
static void put_buffer_byte (struct net_device *dev, unsigned offset, u_char datum);
static void get_whole_buffer (struct net_device *dev, unsigned offset, unsigned length, char *dest);
static void put_whole_buffer (struct net_device *dev, unsigned offset, unsigned length, char *dest);


/* Module parameters */

#ifdef MODULE
static int node=0;
static int io=0x0;	/* <--- EDIT THESE LINES FOR YOUR CONFIGURATION */
static int irq=0;	/* or use the insmod io= irq= shmem= options */
static char *device;	/* use eg. device="arc1" to change name */
static int timeout=3;
static int backplane=0;
static int clock=0;

MODULE_PARM(node,"i");
MODULE_PARM(io, "i");
MODULE_PARM(irq, "i");
MODULE_PARM(device, "s");
MODULE_PARM(timeout,"i");
MODULE_PARM(backplane,"i");
MODULE_PARM(clock,"i");
#else
void __init com20020_setup (char *str, int *ints);
extern struct net_device arcnet_devs[];
extern char arcnet_dev_names[][10];
extern int arcnet_num_devs;
#endif


/* Handy defines for ARCnet specific stuff */

static char *clockrates[]={"2.5 Mb/s","1.25Mb/s","625 Kb/s","312.5 Kb/s",
		    "156.25 Kb/s", "Reserved", "Reserved", 
		    "Reserved"};


/* The number of low I/O ports used by the card. */
#define ARCNET_TOTAL_SIZE 9

#define _INTMASK (ioaddr+0)	/* writable */
#define _STATUS  (ioaddr+0)	/* readable */
#define _COMMAND (ioaddr+1)	/* writable, returns random vals on read (?) */
#define _CONFIG  (ioaddr+6)      /* Configuration register */
#define _DIAGSTAT (ioaddr+1)     /* Diagnostic status register */
#define _MEMDATA  (ioaddr+4)     /* Data port for IO-mapped memory */
#define _ADDR_HI  (ioaddr+2)     /* Control registers for said */
#define _ADDR_LO  (ioaddr+3)

#define RDDATAflag      0x80     /* Next access is a read/~write */
#define NEWNXTIDflag    0x02     /* ID to which token is passed has changed */

#define TXENflag        0x20     /* Enable TX (in CONFIG register) */

#define PROMISCflag     0x10     /* Enable RCV_ALL (in SETUP register) */

#define REGTENTID (lp->config &= ~3);
#define REGNID (lp->config = (lp->config&~2)|1);
#define REGSETUP (lp->config = (lp->config&~1)|2);
#define REGNXTID (lp->config |= 3);

#define ARCRESET { outb(lp->config | 0x80, _CONFIG); \
		    udelay(5);                        \
		    outb(lp->config , _CONFIG);       \
                  }
#define ARCRESET0 { outb(0x18 | 0x80, _CONFIG);   \
		    udelay(5);                       \
		    outb(0x18 , _CONFIG);            \
                  }

#define ARCSTATUS	inb(_STATUS)
#define ACOMMAND(cmd) outb((cmd),_COMMAND)
#define AINTMASK(msk)	outb((msk),_INTMASK)
#define SETCONF 	outb((lp->config),_CONFIG)


/****************************************************************************
 *                                                                          *
 * IO-mapped operation routines                                             *
 *                                                                          *
 ****************************************************************************/

u_char get_buffer_byte (struct net_device *dev, unsigned offset)
{
  int ioaddr=dev->base_addr;

  outb(offset >> 8 | RDDATAflag,  _ADDR_HI); 
  outb(offset & 0xff, _ADDR_LO);

  return inb(_MEMDATA);
}

void put_buffer_byte (struct net_device *dev, unsigned offset, u_char datum)
{
  int ioaddr=dev->base_addr;

  outb(offset >> 8,   _ADDR_HI); 
  outb(offset & 0xff, _ADDR_LO);

  outb(datum, _MEMDATA);
}


#undef ONE_AT_A_TIME_TX
#undef ONE_AT_A_TIME_RX

void get_whole_buffer (struct net_device *dev, unsigned offset, unsigned length, char *dest)
{
  int ioaddr=dev->base_addr;

  outb( (offset >> 8) | AUTOINCflag | RDDATAflag,   _ADDR_HI);
  outb( offset & 0xff,                 _ADDR_LO);

  while (length--)
#ifdef ONE_AT_A_TIME_RX
    *(dest++) = get_buffer_byte(dev,offset++);
#else
    *(dest++) = inb (_MEMDATA);
#endif
}

void put_whole_buffer (struct net_device *dev, unsigned offset, unsigned length, char *dest)
{
  int ioaddr=dev->base_addr;

  outb( (offset >> 8) | AUTOINCflag,   _ADDR_HI);
  outb( offset & 0xff,                 _ADDR_LO);
 
  while (length--)
#ifdef ONE_AT_A_TIME_TX
    put_buffer_byte(dev,offset++,*(dest++));
#else
    outb (*(dest++), _MEMDATA);
#endif
}


static const char *version =
 "com20020.c: v3.00 97/11/09 Avery Pennarun <apenwarr@worldvisions.ca> et al.\n";

/****************************************************************************
 *                                                                          *
 * Probe and initialization                                                 *
 *                                                                          *
 ****************************************************************************/


/* We cannot probe for an IO mapped card either, although we can check that
 * it's where we were told it was, and even autoirq
 */

int __init arc20020_probe(struct net_device *dev)
{
  int ioaddr=dev->base_addr,status,delayval;
  unsigned long airqmask;
  
  BUGLVL(D_NORMAL) printk(version);
  
  if (ioaddr<0x200)
    {
      BUGMSG(D_NORMAL,"No autoprobe for IO mapped cards; you "
	     "must specify the base address!\n");
      return -ENODEV;
    }
  
  if (check_region(ioaddr, ARCNET_TOTAL_SIZE))
    {
      BUGMSG(D_NORMAL,"IO region %xh-%xh already allocated.\n",
	     ioaddr,ioaddr+ARCNET_TOTAL_SIZE-1);
      return -ENXIO;
    }
  
  if (ARCSTATUS == 0xFF)
    {
      BUGMSG(D_NORMAL,"IO address %x empty\n",ioaddr);
      return -ENODEV;
    }
  
  ARCRESET0;
  JIFFER(RESETtime);
  
  status=ARCSTATUS;
  
  if ((status & 0x99) 
      !=  (NORXflag|TXFREEflag|RESETflag))
    {
      BUGMSG(D_NORMAL,"Status invalid (%Xh).\n",status);
      return -ENODEV;
    }
  
  BUGMSG(D_INIT_REASONS,"Status after reset: %X\n",status);
  
  /* Enable TX */
  outb(0x39,_CONFIG);
  outb(inb(ioaddr+8),ioaddr+7);
  
  ACOMMAND(CFLAGScmd|RESETclear|CONFIGclear);
  
  BUGMSG(D_INIT_REASONS,"Status after reset acknowledged: %X\n",status);
  
  /* Reset card. */
  
  outb(0x98,_CONFIG);
  udelay(5);
  outb(0x18,_CONFIG);
  
  /* Read first loc'n of memory */
  
  outb(0 | RDDATAflag | AUTOINCflag ,_ADDR_HI);
  outb(0,_ADDR_LO);
  
  if ((status=inb(_MEMDATA)) != 0xd1)
    {
      BUGMSG(D_NORMAL,"Signature byte not found.\n");
      return -ENODEV;
    }
  
  if (!dev->irq)
    {
      /* if we do this, we're sure to get an IRQ since the
       * card has just reset and the NORXflag is on until
       * we tell it to start receiving.
       */
      BUGMSG(D_INIT_REASONS, "intmask was %d:\n",inb(_INTMASK));
      outb(0, _INTMASK);      
      airqmask = probe_irq_on();
      outb(NORXflag,_INTMASK);
      udelay(1);
      outb(0,_INTMASK);
      dev->irq = probe_irq_off(airqmask);
      
      if (dev->irq<=0)
	{
	  BUGMSG(D_INIT_REASONS,"Autoprobe IRQ failed first time\n");
          airqmask = probe_irq_on();
          outb(NORXflag,_INTMASK);
          udelay(5);
          outb(0,_INTMASK);
          dev->irq = probe_irq_off(airqmask);
          if (dev->irq<=0)
	    {
	      BUGMSG(D_NORMAL,"Autoprobe IRQ failed.\n");
	      return -ENODEV;
            }
	}
    }
  
  return arc20020_found(dev,dev->base_addr,dev->irq);
}


/* Set up the struct net_device associated with this card.  Called after
 * probing succeeds.
 */
int __init arc20020_found(struct net_device *dev,int ioaddr,int airq)
{
  struct arcnet_local *lp;
  
  /* reserve the irq */
  if (request_irq(airq,&arcnet_interrupt,0,"arcnet (COM20020)",dev))
    {
      BUGMSG(D_NORMAL,"Can't get IRQ %d!\n",airq);
      return -ENODEV;
    }
  dev->irq=airq;
  
  /* reserve the I/O region - guaranteed to work by check_region */
  request_region(ioaddr,ARCNET_TOTAL_SIZE,"arcnet (COM20020)");
  dev->base_addr=ioaddr;
  
  dev->mem_start=dev->mem_end=dev->rmem_start=dev->rmem_end=(long)NULL;

  /* Initialize the rest of the device structure. */

  dev->priv = kmalloc(sizeof(struct arcnet_local), GFP_KERNEL);
  if (dev->priv == NULL)
    {
      free_irq(airq,dev);
      release_region(ioaddr,ARCNET_TOTAL_SIZE);
      return -ENOMEM;
    }

  memset(dev->priv,0,sizeof(struct arcnet_local));
  lp=(struct arcnet_local *)(dev->priv);
  lp->card_type = ARC_20020;
  lp->card_type_str = "COM 20020";

  lp->arcnet_reset=arc20020_reset;
  lp->asetmask=arc20020_setmask;
  lp->astatus=arc20020_status;
  lp->acommand=arc20020_command;
  lp->en_dis_able_TX=arc20020_en_dis_able_TX;
  lp->openclose_device=arc20020_openclose;
  lp->prepare_tx=arc20020_prepare_tx;
  lp->inthandler=arc20020_inthandler;

  dev->set_multicast_list = arc20020_set_mc_list;

  /* Fill in the fields of the device structure with generic
   * values.
   */
  arcnet_setup(dev);

  /* And now fill particular fields with arcnet values */
  dev->mtu=1500; /* completely arbitrary - agrees with ether, though */
  dev->hard_header_len=sizeof(struct ClientData);
  lp->sequence=1;
  lp->recbuf=0;

  BUGMSG(D_DURING,"ClientData header size is %d.\n",
	 sizeof(struct ClientData));
  BUGMSG(D_DURING,"HardHeader size is %d.\n",
	 sizeof(struct archdr));

  /* get and check the station ID from offset 1 in shmem */
  lp->timeout = dev->dev_addr[3] & 3; dev->dev_addr[3]=0;
  lp->backplane =dev->dev_addr[1] & 1; dev->dev_addr[1]=0;
  lp->setup = (dev->dev_addr[2] & 7) << 1; dev->dev_addr[2]=0;

  if (dev->dev_addr[0])
    lp->stationid=dev->dev_addr[0];
  else
    lp->stationid=inb(ioaddr+8);            /* FIX ME - We should check that
					       this is valid before using it */
  lp->config = 0x21 | (lp->timeout << 3) | (lp->backplane << 2);
  /* Default 0x38 + register: Node ID */
  SETCONF;
  outb(lp->stationid, ioaddr+7);

  REGSETUP;
  SETCONF;
  outb(lp->setup, ioaddr+7);

  if (!lp->stationid)
    BUGMSG(D_NORMAL,"WARNING!  Station address 00 is reserved "
	   "for broadcasts!\n");
  else if (lp->stationid==255)
    BUGMSG(D_NORMAL,"WARNING!  Station address FF may confuse "
	   "DOS networking programs!\n");
  dev->dev_addr[0]=lp->stationid;

  BUGMSG(D_NORMAL,"ARCnet COM20020: station %02Xh found at %03lXh, IRQ %d.\n",
	 lp->stationid, dev->base_addr,dev->irq);

  if (lp->backplane)
    BUGMSG (D_NORMAL, "Using backplane mode.\n");

  if (lp->timeout != 3)
    BUGMSG (D_NORMAL, "Using Extended Timeout value of %d.\n",lp->timeout);
  if (lp->setup)
    {
      BUGMSG (D_NORMAL, "Using CKP %d - Data rate %s.\n",
	      lp->setup >>1,clockrates[lp->setup >> 1] );
    }
  return 0;
}


/****************************************************************************
 *                                                                          *
 * Utility routines                                                         *
 *                                                                          *
 ****************************************************************************/

/* Do a hardware reset on the card, and set up necessary registers.
 *
 * This should be called as little as possible, because it disrupts the
 * token on the network (causes a RECON) and requires a significant delay.
 *
 * However, it does make sure the card is in a defined state.
 */
int arc20020_reset(struct net_device *dev,int reset_delay)
{
  struct arcnet_local *lp=(struct arcnet_local *)dev->priv;
  short ioaddr=dev->base_addr;
  int delayval,recbuf=lp->recbuf;

  if (reset_delay==3)
    {
      ARCRESET;
      return 0;
    }

  /* no IRQ's, please! */
  lp->intmask=0;
  SETMASK;

  BUGMSG(D_INIT,"Resetting %s (status=%Xh)\n",
	 dev->name,ARCSTATUS);

  lp->config = 0x20 | (lp->timeout<<3) | (lp->backplane<<2);
  /* power-up defaults */
  SETCONF;

  if (reset_delay)
    {
      /* reset the card */
      ARCRESET;
      JIFFER(RESETtime);
    }

  ACOMMAND(CFLAGScmd|RESETclear); /* clear flags & end reset */
  ACOMMAND(CFLAGScmd|CONFIGclear);

  /* verify that the ARCnet signature byte is present */

  if (get_buffer_byte(dev,0) != TESTvalue)
    {
      BUGMSG(D_NORMAL,"reset failed: TESTvalue not present.\n");
      return 1;
    }

  /* clear out status variables */
  recbuf=lp->recbuf=0;
  lp->txbuf=2;

  /* enable extended (512-byte) packets */
  ACOMMAND(CONFIGcmd|EXTconf);

  /* and enable receive of our first packet to the first buffer */
  EnableReceiver();

  /* re-enable interrupts */
  lp->intmask|=NORXflag;
#ifdef DETECT_RECONFIGS
  lp->intmask|=RECONflag;
#endif
  SETMASK;

  /* done!  return success. */
  return 0;
}


/* Set or clear the multicast filter for this adaptor.
 * num_addrs == -1	Promiscuous mode, receive all packets
 * num_addrs == 0	Normal mode, clear multicast list
 * num_addrs > 0	Multicast mode, receive normal and MC packets, and do
 *			best-effort filtering.
 *      FIX ME - do multicast stuff, not just promiscuous.
 */
static void
arc20020_set_mc_list(struct net_device *dev)
{
  struct arcnet_local *lp=dev->priv;
  int ioaddr=dev->base_addr;

  if ((dev->flags & IFF_PROMISC) && (dev->flags & IFF_UP))
    {	/* Enable promiscuous mode */
      if (!(lp->setup & PROMISCflag))
	BUGMSG(D_NORMAL, "Setting promiscuous flag...\n");
      REGSETUP;
      SETCONF;
      lp->setup|=PROMISCflag;
      outb(lp->setup,ioaddr+7);
    } else
      /* Disable promiscuous mode, use normal mode */
      {
	if ((lp->setup & PROMISCflag))
	  BUGMSG(D_NORMAL, "Resetting promiscuous flag...\n");
	REGSETUP;
	SETCONF;
	lp->setup &= ~PROMISCflag;
	outb(lp->setup,ioaddr+7);
      }
}


static void arc20020_openclose(int open)
{
  if (open)
    MOD_INC_USE_COUNT;
  else
    MOD_DEC_USE_COUNT;
}


static void arc20020_en_dis_able_TX(struct net_device *dev, int enable)
{
  struct arcnet_local *lp=(struct arcnet_local *)dev->priv;
  int ioaddr=dev->base_addr;

  lp->config=enable?(lp->config | TXENflag):(lp->config & ~TXENflag);
  SETCONF;
}


static void arc20020_setmask(struct net_device *dev, u_char mask)
{
  short ioaddr=dev->base_addr;

  AINTMASK(mask);
}


static u_char arc20020_status(struct net_device *dev)
{
  short ioaddr=dev->base_addr;

  return ARCSTATUS;
}


static void arc20020_command(struct net_device *dev, u_char cmd)
{
  short ioaddr=dev->base_addr;

  ACOMMAND(cmd);
}


/* The actual interrupt handler routine - handle various IRQ's generated
 * by the card.
 */
static void
arc20020_inthandler(struct net_device *dev)
{
  struct arcnet_local *lp=(struct arcnet_local *)dev->priv;
  int ioaddr=dev->base_addr, status, boguscount = 3, didsomething,
    dstatus;

  AINTMASK(0);

  BUGMSG(D_DURING,"in arc20020_inthandler (status=%Xh, intmask=%Xh)\n",
	 ARCSTATUS,lp->intmask);

  do
    {
      status = ARCSTATUS;
      didsomething=0;


      /* RESET flag was enabled - card is resetting and if RX
       * is disabled, it's NOT because we just got a packet.
       */
      if (status & RESETflag)
	{
	  BUGMSG(D_NORMAL,"spurious reset (status=%Xh)\n",
		 status);
	  arc20020_reset(dev,0);

	  /* all other flag values are just garbage */
	  break;
	}

      /* RX is inhibited - we must have received something. */
      if (status & lp->intmask & NORXflag)
	{
	  int recbuf=lp->recbuf=!lp->recbuf;
	  int oldaddr=0;

	  BUGMSG(D_DURING,"receive irq (status=%Xh)\n",
		 status);

	  /* enable receive of our next packet */
	  EnableReceiver();

	  if (lp->intx)
	    oldaddr=(inb(_ADDR_HI)<<8) | inb(_ADDR_LO);

	  /* Got a packet. */
	  arc20020_rx(dev,!recbuf);

	  if (lp->intx)
	    {
	      outb( (oldaddr >> 8),  _ADDR_HI);
	      outb( oldaddr & 0xff, _ADDR_LO);
	    }

	  didsomething++;
	}

      /* it can only be an xmit-done irq if we're xmitting :) */
      /*if (status&TXFREEflag && !lp->in_txhandler && lp->sending)*/
      if (status & lp->intmask & TXFREEflag)
	{
	  struct Outgoing *out=&(lp->outgoing);
	  int was_sending=lp->sending;

	  lp->intmask &= ~TXFREEflag;

	  lp->in_txhandler++;
	  if (was_sending) lp->sending--;

	  BUGMSG(D_DURING,"TX IRQ (stat=%Xh, numsegs=%d, segnum=%d, skb=%ph)\n",
		 status,out->numsegs,out->segnum,out->skb);

	  if (was_sending && !(status&TXACKflag))
	    {
	      if (lp->lasttrans_dest != 0)
		{
		  BUGMSG(D_EXTRA,"transmit was not acknowledged! (status=%Xh, dest=%02Xh)\n",
			 status,lp->lasttrans_dest);
		  lp->stats.tx_errors++;
		  lp->stats.tx_carrier_errors++;
		}
	      else
		{
		  BUGMSG(D_DURING,"broadcast was not acknowledged; that's normal (status=%Xh, dest=%02Xh)\n",
			 status,
			 lp->lasttrans_dest);
		}
	    }

	  /* send packet if there is one */
	  arcnet_go_tx(dev,0);
	  didsomething++;

	  if (lp->intx)
	    {
	      BUGMSG(D_DURING,"TXDONE while intx! (status=%Xh, intx=%d)\n",
		     ARCSTATUS,lp->intx);
	      lp->in_txhandler--;
	      continue;
	    }

	  if (!lp->outgoing.skb)
	    {
	      BUGMSG(D_DURING,"TX IRQ done: no split to continue.\n");

	      /* inform upper layers */
	      if (!lp->txready) arcnet_tx_done(dev, lp);
	      lp->in_txhandler--;
	      continue;
	    }

	  /* if more than one segment, and not all segments
	   * are done, then continue xmit.
	   */
	  if (out->segnum<out->numsegs)
	    arcnetA_continue_tx(dev);
	  arcnet_go_tx(dev,0);

	  /* if segnum==numsegs, the transmission is finished;
	   * free the skb.
	   */
	  if (out->segnum>=out->numsegs)
	    {
	      /* transmit completed */
	      out->segnum++;
	      if (out->skb)
		{
		  lp->stats.tx_bytes += out->skb->len;
		  dev_kfree_skb(out->skb);
		}
	      out->skb=NULL;

	      /* inform upper layers */
	      if (!lp->txready) arcnet_tx_done(dev, lp);
	    }
	  didsomething++;

	  lp->in_txhandler--;
	}
      else if (lp->txready && !lp->sending && !lp->intx)
	{
	  BUGMSG(D_NORMAL,"recovery from silent TX (status=%Xh)\n",
		 status);
	  arcnet_go_tx(dev,0);
	  didsomething++;
	}

      if ((dstatus=inb(_DIAGSTAT)) & NEWNXTIDflag)
	{
	  REGNXTID;
	  SETCONF;
	  BUGMSG(D_EXTRA,"New NextID detected: %X\n",inb(ioaddr+7));
	}


#ifdef DETECT_RECONFIGS
      if (status & (lp->intmask) & RECONflag)
	{
	  ACOMMAND(CFLAGScmd|CONFIGclear);
	  lp->stats.tx_carrier_errors++;

#ifdef SHOW_RECONFIGS
	  BUGMSG(D_NORMAL,"Network reconfiguration detected (status=%Xh, diag status=%Xh, config=%X)\n",
		 status,dstatus,lp->config);
#endif /* SHOW_RECONFIGS */

#ifdef RECON_THRESHOLD
	  /* is the RECON info empty or old? */
	  if (!lp->first_recon || !lp->last_recon ||
	      jiffies-lp->last_recon > HZ*10)
	    {
	      if (lp->network_down)
		BUGMSG(D_NORMAL,"reconfiguration detected: cabling restored?\n");
	      lp->first_recon=lp->last_recon=jiffies;
	      lp->num_recons=lp->network_down=0;

	      BUGMSG(D_DURING,"recon: clearing counters.\n");
	    }
	  else /* add to current RECON counter */
	    {
	      lp->last_recon=jiffies;
	      lp->num_recons++;

	      BUGMSG(D_DURING,"recon: counter=%d, time=%lds, net=%d\n",
		     lp->num_recons,
		     (lp->last_recon-lp->first_recon)/HZ,
		     lp->network_down);

	      /* if network is marked up;
	       * and first_recon and last_recon are 60+ sec
	       *   apart;
	       * and the average no. of recons counted is
	       *   > RECON_THRESHOLD/min;
	       * then print a warning message.
	       */
	      if (!lp->network_down
		  && (lp->last_recon-lp->first_recon)<=HZ*60
		  && lp->num_recons >= RECON_THRESHOLD)
		{
		  lp->network_down=1;
		  BUGMSG(D_NORMAL,"many reconfigurations detected: cabling problem?\n");
		}
	      else if (!lp->network_down
		       && lp->last_recon-lp->first_recon > HZ*60)
		{
		  /* reset counters if we've gone for
		   * over a minute.
		   */
		  lp->first_recon=lp->last_recon;
		  lp->num_recons=1;
		}
	    }
	}
      else if (lp->network_down && jiffies-lp->last_recon > HZ*10)
	{
	  if (lp->network_down)
	    BUGMSG(D_NORMAL,"cabling restored?\n");
	  lp->first_recon=lp->last_recon=0;
	  lp->num_recons=lp->network_down=0;

	  BUGMSG(D_DURING,"not recon: clearing counters anyway.\n");
#endif
	}
#endif /* DETECT_RECONFIGS */
    } while (--boguscount && didsomething);

  BUGMSG(D_DURING,"net_interrupt complete (status=%Xh, count=%d)\n",
	 ARCSTATUS,boguscount);
  BUGMSG(D_DURING,"\n");

  SETMASK;	/* put back interrupt mask */

}


/* A packet has arrived; grab it from the buffers and pass it to the generic
 * arcnet_rx routing to deal with it.
 */

static void
arc20020_rx(struct net_device *dev,int recbuf)
{
  struct arcnet_local *lp = (struct arcnet_local *)dev->priv;
  int ioaddr=dev->base_addr;
  union ArcPacket packetbuf;
  union ArcPacket *arcpacket=&packetbuf;
  u_char *arcsoft;
  short length,offset;
  u_char daddr,saddr;

  lp->stats.rx_packets++;

  get_whole_buffer(dev,recbuf*512,4,(char *)arcpacket);

  saddr=arcpacket->hardheader.source;

  /* if source is 0, it's a "used" packet! */
  if (saddr==0)
    {
      BUGMSG(D_NORMAL,"discarding old packet. (status=%Xh)\n",
	     ARCSTATUS);
      lp->stats.rx_errors++;
      return;
    }
  /* Set source address to zero to mark it as old */

  put_buffer_byte(dev,recbuf*512,0);

  arcpacket->hardheader.source=0;

  daddr=arcpacket->hardheader.destination;

  if (arcpacket->hardheader.offset1) /* Normal Packet */
    {
      offset=arcpacket->hardheader.offset1;
      arcsoft=&arcpacket->raw[offset];
      length=256-offset;
    }
  else		/* ExtendedPacket or ExceptionPacket */
    {
      offset=arcpacket->hardheader.offset2;
      arcsoft=&arcpacket->raw[offset];
      length=512-offset;
    }

  get_whole_buffer(dev,recbuf*512+offset,length,(char *)arcpacket+offset);

  arcnet_rx(lp, arcsoft, length, saddr, daddr);

  BUGLVL(D_RX) arcnet_dump_packet(lp->adev,arcpacket->raw,length>240,"rx");
}


/* Given an skb, copy a packet into the ARCnet buffers for later transmission
 * by arcnet_go_tx.
 */
static void
arc20020_prepare_tx(struct net_device *dev,u_char *hdr,int hdrlen,
		    char *data,int length,int daddr,int exceptA, int offset)
{
  struct arcnet_local *lp = (struct arcnet_local *)dev->priv;

  lp->txbuf=lp->txbuf^1;	/* XOR with 1 to alternate between 2 and 3 */

  length+=hdrlen;

  BUGMSG(D_TX,"arcnetAS_prep_tx: hdr:%ph, length:%d, data:%ph\n",
	 hdr,length,data);

  put_buffer_byte(dev, lp->txbuf*512+1, daddr);

  /* load packet into shared memory */
  if (length<=MTU)	/* Normal (256-byte) Packet */
    put_buffer_byte(dev, lp->txbuf*512+2, offset=offset?offset:256-length);

  else if (length>=MinTU || offset)	/* Extended (512-byte) Packet */
    {
      put_buffer_byte(dev, lp->txbuf*512+2, 0);
      put_buffer_byte(dev, lp->txbuf*512+3, offset=offset?offset:512-length);
    }
  else if (exceptA)		/* RFC1201 Exception Packet */
    {
      put_buffer_byte(dev, lp->txbuf*512+2, 0);
      put_buffer_byte(dev, lp->txbuf*512+3, offset=512-length-4);

      /* exception-specific stuff - these four bytes
       * make the packet long enough to fit in a 512-byte
       * frame.
       */

      put_buffer_byte(dev, lp->txbuf*512+offset,hdr[0]);
      put_whole_buffer(dev, lp->txbuf*512+offset+1,3,"\377\377\377");
      offset+=4;
    }
  else				/* "other" Exception packet */
    {
      /* RFC1051 - set 4 trailing bytes to 0 */

      put_whole_buffer(dev,lp->txbuf*512+508,4,"\0\0\0\0");

      /* now round up to MinTU */
      put_buffer_byte(dev, lp->txbuf*512+2, 0);
      put_buffer_byte(dev, lp->txbuf*512+3, offset=512-MinTU);
    }

  /* copy the packet into ARCnet shmem
   *  - the first bytes of ClientData header are skipped
   */

  put_whole_buffer(dev, 512*lp->txbuf+offset, hdrlen,(u_char *)hdr);
  put_whole_buffer(dev, 512*lp->txbuf+offset+hdrlen,length-hdrlen,data);

  BUGMSG(D_DURING,"transmitting packet to station %02Xh (%d bytes)\n",
	 daddr,length);

  lp->lastload_dest=daddr;
  lp->txready=lp->txbuf;	/* packet is ready for sending */
}


/****************************************************************************
 *                                                                          *
 * Kernel Loadable Module Support                                           *
 *                                                                          *
 ****************************************************************************/


#ifdef MODULE

static struct net_device *cards[16]={NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,
			  NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL};


int init_module(void)
{
  struct net_device *dev;

  cards[0]=dev=(struct net_device *)kmalloc(sizeof(struct net_device), GFP_KERNEL);
  if (!dev)
    return -ENOMEM;

  memset(dev, 0, sizeof(struct net_device));

  dev->name=(char *)kmalloc(9, GFP_KERNEL);
  if (!dev->name)
    {
      kfree(dev);
      return -ENOMEM;
    }
  dev->init=arc20020_probe;

  if (device)
    strcpy(dev->name,device);
  else arcnet_makename(dev->name);

  if (node && node != 0xff)
    dev->dev_addr[0]=node;

  if (backplane) dev->dev_addr[1]=backplane?1:0;
  if (clock) dev->dev_addr[2]=clock&7;
  dev->dev_addr[3]=timeout&3;

  dev->base_addr=io;
  dev->irq=irq;

  if (dev->irq==2) dev->irq=9;

  if (register_netdev(dev) != 0)
    return -EIO;

  /* Increase use count of arcnet.o */
  arcnet_use_count(1);

  return 0;
}

void cleanup_module(void)
{
  struct net_device *dev=cards[0];
  int ioaddr=dev->base_addr;

  if (dev->start) (*dev->stop)(dev);

  /* Flush TX and disable RX */
  if (ioaddr)
    {
      AINTMASK(0);		/* disable IRQ's */
      ACOMMAND(NOTXcmd);	/* stop transmit */
      ACOMMAND(NORXcmd);	/* disable receive */
    }

  if (dev->irq)
    {
      free_irq(dev->irq,dev);
    }

  if (dev->base_addr) release_region(dev->base_addr,ARCNET_TOTAL_SIZE);
  unregister_netdev(dev);
  kfree(dev->priv);
  dev->priv = NULL;

  /* Decrease use count of arcnet.o */
  arcnet_use_count(0);
}

#else

void __init com20020_setup (char *str, int *ints)
{
  struct net_device *dev;

  if (arcnet_num_devs == MAX_ARCNET_DEVS)
    {
      printk("com20020: Too many ARCnet devices registered (max %d).\n",
	     MAX_ARCNET_DEVS);
      return;
    }

  dev=&arcnet_devs[arcnet_num_devs];

  if (ints[0] < 1)
    {
      printk("com20020: You must give an IO address.\n");
      return;
    }

  dev->dev_addr[3]=3;
  dev->init=arc20020_probe;

  switch(ints[0])
    {
    case 7: /* ERROR */
      printk("com20020: Too many arguments.\n");

    case 6: /* Timeout */
      dev->dev_addr[3]=(u_char)ints[6];

    case 5: /* CKP value */
      dev->dev_addr[2]=(u_char)ints[5];

    case 4: /* Backplane flag */
      dev->dev_addr[1]=(u_char)ints[4];

    case 3: /* Node ID */
      dev->dev_addr[0]=(u_char)ints[3];

    case 2: /* IRQ */
      dev->irq=ints[2];

    case 1: /* IO address */
      dev->base_addr=ints[1];
    }

  dev->name = (char *)&arcnet_dev_names[arcnet_num_devs];

  if (str)
    strncpy(dev->name, str, 9);

  arcnet_num_devs++;
}
#endif /* MODULE */
