depca_interrupt(int reg_ptr)
{
    int irq = -(((struct pt_regs *)reg_ptr)->orig_eax+2);
    struct device *dev = (struct device *)(irq2dev_map[irq]);
    struct depca_private *lp;
    int csr0, ioaddr, nicsr;

    if (dev == NULL) {
	printk ("depca_interrupt(): irq %d for unknown device.\n", irq);
	return;
    } else {
      lp = (struct depca_private *)dev->priv;
      ioaddr = dev->base_addr;
    }

    if (dev->interrupt)
	printk("%s: Re-entering the interrupt handler.\n", dev->name);

    dev->interrupt = MASK_INTERRUPTS;

    /* mask the DEPCA board interrupts and turn on the LED */
    nicsr = inw(DEPCA_NICSR);
    nicsr |= (IM|LED);
    outw(nicsr, DEPCA_NICSR);

    outw(CSR0, DEPCA_ADDR);
    csr0 = inw(DEPCA_DATA);

    /* Acknowledge all of the current interrupt sources ASAP. */
    outw(csr0 & ~(INEA|TDMD|STOP|STRT|INIT), DEPCA_DATA);

    if (depca_debug > 5)
	printk("%s: interrupt  csr0=%#2.2x new csr=%#2.2x.\n",
	       dev->name, csr0, inw(DEPCA_DATA));

    if (csr0 & RINT)		/* Rx interrupt (packet arrived) */
	depca_rx(dev);

    if (csr0 & TINT) 	        /* Tx interrupt (packet sent) */
        depca_tx(dev);

    /* Clear the interrupts we've handled. */
    outw(CSR0, DEPCA_ADDR);
    outw(BABL|CERR|MISS|MERR|RINT|TINT|IDON|INEA, DEPCA_DATA);

    if (depca_debug > 4) {
      printk("%s: exiting interrupt, csr%d=%#4.4x.\n",
	     dev->name, inw(DEPCA_ADDR),
	     inw(DEPCA_DATA));
    }

    /* Unmask the DEPCA board interrupts and turn off the LED */
    nicsr = (nicsr & ~IM & ~LED);
    outw(nicsr, DEPCA_NICSR);

    dev->interrupt = UNMASK_INTERRUPTS;
    return;
}

static int
depca_rx(struct device *dev)
{
    struct depca_private *lp = (struct depca_private *)dev->priv;
    int entry = lp->cur_rx & lp->rmask;

    /* If we own the next entry, it's a new packet. Send it up. */
    for (; lp->rx_ring[entry].base >= 0; entry = (++lp->cur_rx) & lp->rmask) {
	int status = lp->rx_ring[entry].base >> 16 ;

	if (status & R_ERR) {	       /* There was an error. */
	    lp->stats.rx_errors++;     /* Update the error stats. */
	    if (status & R_FRAM) lp->stats.rx_frame_errors++;
	    if (status & R_OFLO) lp->stats.rx_over_errors++;
	    if (status & R_CRC)  lp->stats.rx_crc_errors++;
	    if (status & R_BUFF) lp->stats.rx_fifo_errors++;
	} else {	  /* Malloc up new buffer, compatible  with net-2e. */
	    short pkt_len = lp->rx_ring[entry].msg_length;
	    int sksize = sizeof(struct sk_buff) + pkt_len;
	    struct sk_buff *skb;

	    skb = alloc_skb(sksize, GFP_ATOMIC);
	    if (skb == NULL) {
		printk("%s: Memory squeeze, deferring packet.\n", dev->name);
		lp->stats.rx_dropped++;	/* Really, deferred. */
		break;
	    }
	    skb->mem_len = sksize;
	    skb->mem_addr = skb;
	    skb->len = pkt_len;
	    skb->dev = dev;
	    memcpy(skb->data,
		   (unsigned char *)(lp->rx_ring[entry].base & 0x00ffffff),
		   pkt_len);
	    /* 
	    ** Notify the upper protocol layers that there is another 
	    ** packet to handle
	    */
#ifdef HAVE_NETIF_RX
	    netif_rx(skb);
#else
	    skb->lock = 0;
	    if (dev_rint((unsigned char*)skb, pkt_len, IN_SKBUFF, dev) != 0) {
		kfree_skbmem(skb, sksize);
		lp->stats.rx_dropped++;
		break;
	    }
#endif
	    lp->stats.rx_packets++;
	}

	/* turn over ownership of the current entry back to the LANCE */
	lp->rx_ring[entry].base |= R_OWN;
    }

    /* 
    ** We should check that at least two ring entries are free.  If not,
    ** we should free one and mark stats->rx_dropped++. 
    */

    return 0;
}

/*
** Buffer sent - check for buffer errors.
*/
static int
depca_tx(struct device *dev)
{
  struct depca_private *lp = (struct depca_private *)dev->priv;
  int dirty_tx = lp->dirty_tx & lp->rmask;

  if (depca_debug > 5)
    printk("%s: Cleaning tx ring, dirty %d clean %d.\n",
	   dev->name, dirty_tx, (lp->cur_tx & lp->rmask));
  
  /* 
  ** While the dirty entry is not the current one AND 
  ** the LANCE doesn't own it... 
  */
  for (; dirty_tx!=(lp->cur_tx & lp->rmask) && lp->tx_ring[dirty_tx].base>0;
                                       dirty_tx = ++lp->dirty_tx & lp->rmask) {
    unsigned long *tmdp = (unsigned long *)(&lp->tx_ring[dirty_tx]);
    int status = lp->tx_ring[dirty_tx].base >> 16;

    if (status < 0) {                          /* Packet not yet sent! */
      printk("interrupt for packet not yet sent!\n");
      break;
    }
    if (status & T_ERR) { /* There was an major error, log it. */
      int err_status = lp->tx_ring[dirty_tx].misc;

      lp->stats.tx_errors++;
      if (err_status & TMD3_RTRY) lp->stats.tx_aborted_errors++;
      if (err_status & TMD3_LCAR) lp->stats.tx_carrier_errors++;
      if (err_status & TMD3_LCOL) lp->stats.tx_window_errors++;
      if (err_status & TMD3_UFLO) lp->stats.tx_fifo_errors++;
      /* We should re-init() after the FIFO error. */
    } else if (status & (T_MORE | T_ONE)) {
      lp->stats.collisions++;
    } else {
      lp->stats.tx_packets++;
    }

    if (depca_debug > 5)
      printk("%s: Tx done entry %d, %4.4lx %4.4lx %4.4lx %4.4lx.\n",
	     dev->name, dirty_tx,
	     tmdp[0], tmdp[1], tmdp[2], tmdp[3]);
  }
  /*mark_bh(INET_BH);*/
  return 0;
}

static int
depca_close(struct device *dev)
{
    int ioaddr = dev->base_addr;

    dev->start = 0;
    dev->tbusy = 1;

    outw(CSR0, DEPCA_ADDR);

    if (depca_debug > 1) {
      printk("%s: Shutting down ethercard, status was %2.2x.\n",
	     dev->name, inw(DEPCA_DATA));
    }

    /* 
    ** We stop the DEPCA here -- it occasionally polls
    ** memory if we don't. 
    */
    outw(STOP, DEPCA_DATA);

    free_irq(dev->irq);

    irq2dev_map[dev->irq] = 0;

    return 0;
}

static void LoadCSRs(struct device *dev)
{
  struct depca_private *lp = (struct depca_private *)dev->priv;
  int ioaddr = dev->base_addr;

  outw(CSR1, DEPCA_ADDR);                /* initialisation block address LSW */
  outw((unsigned short)(unsigned long)&lp->init_block, DEPCA_DATA);
  outw(CSR2, DEPCA_ADDR);                /* initialisation block address MSW */
  outw((unsigned short)((unsigned long)&lp->init_block >> 16), DEPCA_DATA);
  outw(CSR3, DEPCA_ADDR);                /* ALE control */
  outw(ACON, DEPCA_DATA);
  outw(CSR0, DEPCA_ADDR);                /* point back to CSR0 */
}

static int InitRestartDepca(struct device *dev)
{
  struct depca_private *lp = (struct depca_private *)dev->priv;
  int ioaddr = dev->base_addr;
  int i, status=0;

  outw(CSR0, DEPCA_ADDR);                /* point back to CSR0 */
  outw(INIT, DEPCA_DATA);                /* initialize DEPCA */

  /* wait for lance to complete initialisation */
  for (i=0;(i<100) && !(inw(DEPCA_DATA) & IDON); i++); 

  if (i!=100) {
    /* clear IDON by writing a "1", enable interrupts and start lance */
    outw(IDON | INEA | STRT, DEPCA_DATA);
    if (depca_debug > 2) {
      printk("%s: DEPCA open after %d ticks, init block %#lx csr0 %4.4x.\n",
	     dev->name, i, (long) &lp->init_block, inw(DEPCA_DATA));
    }
  } else {
    status = -1;
    printk("%s: DEPCA unopened after %d ticks, init block %#lx csr0 %4.4x.\n",
	   dev->name, i, (long) &lp->init_block, inw(DEPCA_DATA));
  }

  return status;
}

static struct enet_statistics *
depca_get_stats(struct device *dev)
{
    struct depca_private *lp = (struct depca_private *)dev->priv;

    /* Null body since there is no framing error counter */

    return &lp->stats;
}

#ifdef HAVE_MULTICAST
/*
** 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.
*/
static void
set_multicast_list(struct device *dev, int num_addrs, void *addrs)
{
  short ioaddr = dev->base_addr;
  struct depca_private *lp = (struct depca_private *)dev->priv;
  
  /* We take the simple way out and always enable promiscuous mode. */
  STOP_DEPCA;                       /* Temporarily stop the depca.  */

  lp->init_block.mode = PROM;       /* Set promiscuous mode */
  if (num_addrs >= 0) {
    short multicast_table[4];
    int i;

    SetMulticastFilter(num_addrs, (char *)addrs, (char *)multicast_table);

    /* We don't use the multicast table, but rely on upper-layer filtering. */
    memset(multicast_table, (num_addrs==0) ? 0 : -1, sizeof(multicast_table));

    for (i = 0; i < 4; i++) {
      lp->init_block.filter[i] = multicast_table[i];
    }
    lp->init_block.mode &= ~PROM; /* Unset promiscuous mode */
  } else {
    lp->init_block.mode |= PROM;    /* Set promiscuous mode */
  }

  outw(CSR0, DEPCA_ADDR);
  outw(IDON|INEA|STRT, DEPCA_DATA); /* Resume normal operation. */
}

/*
** Calculate the hash code and update the logical address filter
** from a list of ethernet multicast addresses.
** Derived from a 'C' program in the AMD data book:
** "Am79C90 CMOS Local Area Network Controller for Ethernet (C-LANCE)", 
** Pub #17781, Rev. A, May 1993
*/
static void SetMulticastFilter(int num_addrs, char *addrs, char *multicast_table)
{
  char j, ctrl, bit, octet, hashcode;
  short int i;
  long int CRC, poly = (long int) CRC_POLYNOMIAL;

  for (i=0;i<num_addrs;i++) {                /* for each address in the list */
    if (((char) *(addrs+ETH_ALEN*i) & 0x01) == 1) {/* is multicast address? */ 
      CRC = (long int) 0xffffffff;           /* init CRC for each address */
      for (octet=0;octet<ETH_ALEN;octet++) { /* for each address octet */
	for(j=0;j<8;j++) {                   /* process each address bit */
	  bit = (((char)* (addrs+ETH_ALEN*i+octet)) >> j) & 0x01;
	  ctrl = ((CRC < 0) ? 1 : 0);        /* shift the control bit */
	  CRC <<= 1;                         /* shift the CRC */
	  if (bit ^ ctrl) {                  /* (bit) XOR (control bit) */
	    CRC ^= poly;                     /* (CRC) XOR (polynomial) */
	  }
	}
      }
      hashcode = (CRC & 0x00000001);         /* hashcode is 6 LSb of CRC ... */
      for (j=0;j<5;j++) {                    /* ... in reverse order. */
	hashcode <<= 1;
	CRC >>= 1;
	hashcode |= (CRC & 0x00000001);
      }                                      
      octet = hashcode >> 3;                  /* bit[3-5] -> octet in filter */
                                              /* bit[0-2] -> bit in octet */
      multicast_table[octet] |= (1 << (hashcode & 0x07));
    }
  }
  return;
}

#endif  /* HAVE_MULTICAST */

/*
** Look for a particular board name in the on-board Remote Diagnostics
** and Boot (RDB) ROM. This will also give us a clue to the network RAM
** base address.
*/
static char *DepcaSignature(unsigned long mem_addr)
{
  unsigned long i,j,k;
  static char signatures[][DEPCA_NAME_LENGTH] = DEPCA_SIGNATURE;
  static char thisName[DEPCA_NAME_LENGTH];
  char tmpstr[17];

  for (i=0;i<16;i++) {                  /* copy the first 16 bytes of ROM to */
    tmpstr[i] = *(unsigned char *)(mem_addr+0xc000+i); /* a temporary string */
  }
  tmpstr[i]=(char)NULL;

  strcpy(thisName,"");
  for (i=0;*signatures[i]!=(char)NULL && *thisName==(char)NULL;i++) {
    for (j=0,k=0;j<16 && k<strlen(signatures[i]);j++) {
      if (signatures[i][k] == tmpstr[j]) {              /* track signature */
	k++;
      } else {                     /* lost signature; begin search again */
	k=0;
      }
    }
    if (k == strlen(signatures[i])) {
      strcpy(thisName,signatures[i]);
    }
  }

  return thisName;                    /* return the device name string */
}

/*
** Look for a special sequence in the Ethernet station address PROM that
** is common across all DEPCA products.
*/

static int DevicePresent(short ioaddr)
{
  static short fp=1,sigLength=0;
  static char devSig[] = PROBE_SEQUENCE;
  char data;
  int i, j, status = 0;
  static char asc2hex(char value);

/* 
** Convert the ascii signature to a hex equivalent & pack in place 
*/
  if (fp) {                               /* only do this once!... */
    for (i=0,j=0;devSig[i]!=(char)NULL && !status;i+=2,j++) {
      if ((devSig[i]=asc2hex(devSig[i]))>=0) {
	devSig[i]<<=4;
	if((devSig[i+1]=asc2hex(devSig[i+1]))>=0){
	  devSig[j]=devSig[i]+devSig[i+1];
	} else {
	  status= -1;
	}
      } else {
	status= -1;
      }
    }
    sigLength=j;
    fp = 0;
  }

/* 
** Search the Ethernet address ROM for the signature. Since the ROM address
** counter can start at an arbitrary point, the search must include the entire
** probe sequence length plus the length of the (signature - 1).
** Stop the search IMMEDIATELY after the signature is found so that the
** PROM address counter is correctly positioned at the start of the
** ethernet address for later read out.
*/
  if (!status) {
    for (i=0,j=0;j<sigLength && i<PROBE_LENGTH+sigLength-1;i++) {
      data = inb(ioaddr);
      if (devSig[j] == data) {    /* track signature */
	j++;
      } else {                    /* lost signature; begin search again */
	j=0;
      }
    }

    if (j!=sigLength) {
      status = -ENODEV;           /* search failed */
    }
  }

  return status;
}

static char asc2hex(char value)
{
  value -= 0x30;                  /* normalise to 0..9 range */
  if (value >= 0) {
    if (value > 9) {              /* but may not be 10..15 */
      value &= 0x1f;              /* make A..F & a..f be the same */
      value -= 0x07;              /* normalise to 10..15 range */
      if ((value < 0x0a) || (value > 0x0f)) { /* if outside range then... */
	value = -1;               /* ...signal error */
      }
    }
  } else {                        /* outside 0..9 range... */
    value = -1;                   /* ...signal error */
  }
  return value;                   /* return hex char or error */
}


/*
 * Local variables:
 *  compile-command: "gcc -D__KERNEL__ -I/usr/src/linux/net/inet -Wall -Wstrict-prototypes -O6 -m486 -c depca.c"
 * End:
 */