/*
net-3-driver for the 3c523 Etherlink/MC card (i82586 Ethernet chip)


This is an extension to the Linux operating system, and is covered by the
same Gnu Public License that covers that work.

Copyright 1995, 1996 by Chris Beauregard (cpbeaure@undergrad.math.uwaterloo.ca)

This is basically Michael Hipp's ni52 driver, with a new probing
algorithm and some minor changes to the 82586 CA and reset routines.
Thanks a lot Michael for a really clean i82586 implementation!  Unless
otherwise documented in ni52.c, any bugs are mine.

Contrary to the Ethernet-HOWTO, this isn't based on the 3c507 driver in
any way.  The ni52 is a lot easier to modify.

sources:
  ni52.c

  Crynwr packet driver collection was a great reference for my first
  attempt at this sucker.  The 3c507 driver also helped, until I noticed
  that ni52.c was a lot nicer.

  EtherLink/MC: Micro Channel Ethernet Adapter Technical Reference
  Manual, courtesy of 3Com CardFacts, documents the 3c523-specific
  stuff.  Information on CardFacts is found in the Ethernet HOWTO.
  Also see <a href="http://www.3com.com/">

  Microprocessor Communications Support Chips, T.J. Byers, ISBN
  0-444-01224-9, has a section on the i82586.  It tells you just enough
  to know that you really don't want to learn how to program the chip.

  The original device probe code was stolen from ps2esdi.c

Known Problems:
  Since most of the code was stolen from ni52.c, you'll run across the
  same bugs in the 0.62 version of ni52.c, plus maybe a few because of
  the 3c523 idiosynchacies.  The 3c523 has 16K of RAM though, so there
  shouldn't be the overrun problem that the 8K ni52 has.

  This driver is for a 16K adapter.  It should work fine on the 64K
  adapters, but it will only use one of the 4 banks of RAM.  Modifying
  this for the 64K version would require a lot of heinous bank
  switching, which I'm sure not interested in doing.  If you try to
  implement a bank switching version, you'll basically have to remember
  what bank is enabled and do a switch everytime you access a memory
  location that's not current.  You'll also have to remap pointers on
  the driver side, because it only knows about 16K of the memory.
  Anyone desperate or masochistic enough to try?

  It seems to be stable now when multiple transmit buffers are used.  I
  can't see any performance difference, but then I'm working on a 386SX.

  Multicast doesn't work.  It doesn't even pretend to work.  Don't use
  it.  Don't compile your kernel with multicast support.  I don't know
  why.

Features:
  This driver is useable as a loadable module.  If you try to specify an
  IRQ or a IO address (via insmod 3c523.o irq=xx io=0xyyy), it will
  search the MCA slots until it finds a 3c523 with the specified
  parameters.

  This driver should support multiple ethernet cards, but I can't test
  that.  If someone would I'd greatly appreciate it.

  This has been tested with both BNC and TP versions, internal and
  external transceivers.  Haven't tested with the 64K version (that I
  know of).

History:
  Jan 1st, 1996
  	first public release
  Feb 4th, 1996
	update to 1.3.59, incorporated multicast diffs from ni52.c
  Feb 15th, 1996
  	added shared irq support

  $Header: /fsys2/home/chrisb/linux-1.3.59-MCA/drivers/net/RCS/3c523.c,v 1.1 1996/02/05 01:53:46 chrisb Exp chrisb $
*/

#ifdef MODULE
#include <linux/module.h>
#endif

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/malloc.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/mca.h>
#include <asm/processor.h>
#include <asm/bitops.h>
#include <asm/io.h>

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>

#include "3c523.h"

/*************************************************************************/
#define DEBUG       /* debug on */
#define SYSBUSVAL 0 /* 1 = 8 Bit, 0 = 16 bit - 3c523 only does 16 bit*/

#define make32(ptr16) (p->memtop + (short) (ptr16) )
#define make24(ptr32) ((char *) (ptr32) - p->base)
#define make16(ptr32) ((unsigned short) ((unsigned long) (ptr32) - (unsigned long) p->memtop ))

/*************************************************************************/
/*
    Tables to which we can map values in the configuration registers.
*/
static int irq_table[] __initdata = {12, 7, 3, 9};
static int csr_table[] __initdata = {0x300, 0x1300, 0x2300, 0x3300};
static int shm_table[] __initdata = {0x0c0000, 0x0c8000, 0x0d0000, 0x0d8000};

/******************* how to calculate the buffers *****************************


  * IMPORTANT NOTE: if you configure only one NUM_XMIT_BUFFS, the driver works
  * --------------- in a different (more stable?) mode. Only in this mode it's
  *                 possible to configure the driver with 'NO_NOPCOMMANDS'

sizeof(scp)=12; sizeof(scb)=16; sizeof(iscp)=8;
sizeof(scp)+sizeof(iscp)+sizeof(scb) = 36 = INIT
sizeof(rfd) = 24; sizeof(rbd) = 12;
sizeof(tbd) = 8; sizeof(transmit_cmd) = 16;
sizeof(nop_cmd) = 8;

  * if you don't know the driver, better do not change this values: */

#define RECV_BUFF_SIZE 1524 /* slightly oversized */
#define XMIT_BUFF_SIZE 1524 /* slightly oversized */
#define NUM_XMIT_BUFFS 4    /* config for both, 8K and 16K shmem */
#define NUM_RECV_BUFFS_8  1 /* config for 8K shared mem */
#define NUM_RECV_BUFFS_16 6 /* config for 16K shared mem */

#if (NUM_XMIT_BUFFS == 1)
#define NO_NOPCOMMANDS      /* only possible with NUM_XMIT_BUFFS=1 */
#endif

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

#define DELAY(x) {int i=jiffies; \
                  if(loops_per_sec == 1) \
                     while(i+(x)>jiffies); \
                  else \
                     __delay((loops_per_sec>>5)*x); \
                 }

/* a much shorter delay: */
#define DELAY_16(); { __delay( (loops_per_sec>>16)+1 ); }

/* wait for command with timeout: */
#define WAIT_4_SCB_CMD() { int i; \
  for(i=0;i<1024;i++) { \
    if(!p->scb->cmd) break; \
    DELAY_16(); \
    if(i == 1023) { \
      printk("%s:%d: scb_cmd timed out .. resetting i82586\n",\
      	dev->name,__LINE__); \
      elmc_id_reset586(); } } }

static void    elmc_interrupt(int irq,void *dev_id,struct pt_regs *reg_ptr);
static int     elmc_open(struct device *dev);
static int     elmc_close(struct device *dev);
static int     elmc_send_packet(struct sk_buff *,struct device *);
static struct  net_device_stats *elmc_get_stats(struct device *dev);
static void    set_multicast_list(struct device *dev);

/* helper-functions */
static int     init586(struct device *dev);
static int     check586(struct device *dev,char *where,unsigned size);
static void    alloc586(struct device *dev);
static void    startrecv586(struct device *dev);
static void   *alloc_rfa(struct device *dev,void *ptr);
static void    elmc_rcv_int(struct device *dev);
static void    elmc_xmt_int(struct device *dev);
static void    elmc_rnr_int(struct device *dev);

struct priv 
{
	struct net_device_stats stats;
	unsigned long base;
	char *memtop;
	volatile struct rfd_struct	*rfd_last,*rfd_top,*rfd_first;
	volatile struct scp_struct	*scp;	/* volatile is important */
	volatile struct iscp_struct *iscp; /* volatile is important */
	volatile struct scb_struct  *scb;  /* volatile is important */
	volatile struct tbd_struct  *xmit_buffs[NUM_XMIT_BUFFS];
	volatile struct transmit_cmd_struct *xmit_cmds[NUM_XMIT_BUFFS];
#if (NUM_XMIT_BUFFS == 1)
	volatile struct nop_cmd_struct *nop_cmds[2];
#else
	volatile struct nop_cmd_struct *nop_cmds[NUM_XMIT_BUFFS];
#endif
	volatile int    nop_point,num_recv_buffs;
	volatile char  *xmit_cbuffs[NUM_XMIT_BUFFS];
	volatile int    xmit_count,xmit_last;
	volatile int slot;
};

#define elmc_attn586()  {elmc_do_attn586(dev->base_addr,ELMC_CTRL_INTE);}
#define elmc_reset586() {elmc_do_reset586(dev->base_addr,ELMC_CTRL_INTE);}

/* with interrupts disabled - this will clear the interrupt bit in the
3c523 control register, and won't put it back.  This effectively
disables interrupts on the card. */
#define elmc_id_attn586()  {elmc_do_attn586(dev->base_addr,0);}
#define elmc_id_reset586() {elmc_do_reset586(dev->base_addr,0);}

/*************************************************************************/
/*
	Do a Channel Attention on the 3c523.  This is extremely board dependent.
*/
static
void
elmc_do_attn586( int ioaddr, int ints ) {
    /* the 3c523 requires a minimum of 500 ns.  The delays here might be
    a little too large, and hence they may cut the performance of the
    card slightly.  If someone who knows a little more about Linux
    timing would care to play with these, I'd appreciate it. */

    /* this bit masking stuff is crap.  I'd rather have separate
    registers with strobe triggers for each of these functions.  <sigh>
    Ya take what ya got. */

    outb( ELMC_CTRL_RST|0x3|ELMC_CTRL_CA|ints, ioaddr + ELMC_CTRL);
    DELAY_16();	/* > 500 ns */
    outb( ELMC_CTRL_RST|0x3|ints, ioaddr + ELMC_CTRL);
}

/*************************************************************************/
/*
	Reset the 82586 on the 3c523.  Also very board dependent.
*/
static
void
elmc_do_reset586( int ioaddr, int ints ) {
    /* toggle the RST bit low then high */
    outb( 0x3|ELMC_CTRL_LBK, ioaddr + ELMC_CTRL );
    DELAY_16();	/* > 500 ns */
    outb( ELMC_CTRL_RST|ELMC_CTRL_LBK|0x3, ioaddr + ELMC_CTRL );

	elmc_do_attn586( ioaddr, ints );
}

/**********************************************
 * close device
 */

static
int
elmc_close(struct device *dev) {
  elmc_id_reset586(); /* the hard way to stop the receiver */

  free_irq(dev->irq, dev);

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

#ifdef MODULE
	MOD_DEC_USE_COUNT;
#endif

  return 0;
}

/**********************************************
 * open device
 */

static
int
elmc_open(struct device *dev) {

  elmc_id_attn586();	/* disable interrupts */

  if(request_irq( dev->irq, &elmc_interrupt, SA_SHIRQ|SA_SAMPLE_RANDOM,
  	"3c523", dev )
  ) {
    printk( "%s: couldn't get irq %d\n", dev->name, dev->irq );
    elmc_id_reset586();
    return -EAGAIN;
  }

  alloc586(dev);
  init586(dev);
  startrecv586(dev);

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

#ifdef MODULE
	MOD_INC_USE_COUNT;
#endif

  return 0; /* most done by init */
}

/**********************************************
 * Check to see if there's an 82586 out there.
 */

__initfunc(static
int
check586( struct device *dev, char *where, unsigned size)) {
  struct priv *p = (struct priv *) dev->priv;
  char *iscp_addrs[2];
  int i = 0;

  p->base = (unsigned long) where + size - 0x01000000;
  p->memtop = where + size;
  p->scp = (struct scp_struct *)(p->base + SCP_DEFAULT_ADDRESS);
  memset((char *)p->scp,0, sizeof(struct scp_struct));
  p->scp->sysbus = SYSBUSVAL;        /* 1 = 8Bit-Bus, 0 = 16 Bit */

  iscp_addrs[0] = where;
  iscp_addrs[1]= (char *) p->scp - sizeof(struct iscp_struct);

  for( i = 0; i < 2; i ++ ) {
    p->iscp = (struct iscp_struct *) iscp_addrs[i];
    memset((char *)p->iscp,0, sizeof(struct iscp_struct));

    p->scp->iscp = make24(p->iscp);
    p->iscp->busy = 1;

    elmc_id_reset586();

    /* reset586 does an implicit CA */

    /* apparently, you sometimes have to kick the 82586 twice... */
    elmc_id_attn586();

    if(p->iscp->busy) { /* i82586 clears 'busy' after successful init */
      return 0;
    }
  }

  return 1;
}

/******************************************************************
 * set iscp at the right place, called by elmc_probe and open586.
 */

void
alloc586( struct device *dev ) {
  struct priv *p =  (struct priv *) dev->priv;

  elmc_id_reset586();
  DELAY(2);

  p->scp  = (struct scp_struct *)  (p->base + SCP_DEFAULT_ADDRESS);
  p->scb  = (struct scb_struct *)  (dev->mem_start);
  p->iscp = (struct iscp_struct *) ((char *)p->scp - sizeof(struct iscp_struct));

  memset((char *) p->iscp,0,sizeof(struct iscp_struct));
  memset((char *) p->scp ,0,sizeof(struct scp_struct));

  p->scp->iscp = make24(p->iscp);
  p->scp->sysbus = SYSBUSVAL;
  p->iscp->scb_offset = make16(p->scb);

  p->iscp->busy = 1;
  elmc_id_reset586();
  elmc_id_attn586();

  DELAY(2);

  if(p->iscp->busy) {
    printk("%s: Init-Problems (alloc).\n",dev->name);
  }

  memset((char *)p->scb,0,sizeof(struct scb_struct));
}

/*****************************************************************/
static int
elmc_getinfo( char* buf, int slot, void* d ) {
	int len = 0;
	struct device* dev = (struct device*) d;
	int i;

	if( dev == NULL ) return len;

	len += sprintf( buf+len, "Revision: 0x%x\n",
		inb( dev->base_addr + ELMC_REVISION ) & 0xf );
	len += sprintf( buf+len, "IRQ: %d\n", dev->irq );
	len += sprintf( buf+len, "IO Address: %#lx-%#lx\n", dev->base_addr,
		dev->base_addr+ELMC_IO_EXTENT );
	len += sprintf( buf+len, "Memory: %#lx-%#lx\n", dev->mem_start,
		dev->mem_end-1 );
	len += sprintf( buf+len, "Transceiver: %s\n", dev->if_port ?
		"External" : "Internal" );
	len += sprintf( buf+len, "Device: %s\n", dev->name );
	len += sprintf( buf+len, "Hardware Address:" );
	for (i = 0; i < 6; i ++ ) {
		len += sprintf( buf+len, " %02x", dev->dev_addr[i] );
	}
	buf[len++] = '\n';
	buf[len] = 0;

	return len;
} /* elmc_getinfo() */

/*****************************************************************/
__initfunc(int
elmc_probe(struct device *dev)) {
    static int slot = 0;
    int base_addr = dev ? dev->base_addr : 0;
    int irq = dev ? dev->irq : 0;
    u_char status = 0;
    u_char revision = 0;
    int i = 0;
    unsigned int size = 0;

    if( MCA_bus == 0 ) {
    	return ENODEV;
    }

	/* search through the slots for the 3c523. */
	slot = mca_find_adapter( ELMC_MCA_ID, 0 );
	while( slot != -1 ) {
		status = mca_read_stored_pos( slot, 2 );

		/*
			If we're trying to match a specified irq or IO address,
			we'll reject a match unless it's what we're looking for.
		*/
		if( base_addr || irq ) {
			/* we're looking for a card at a particular place */

			if( irq &&
				irq != irq_table[ (status & ELMC_STATUS_IRQ_SELECT) >> 6]
			) {
				slot = mca_find_adapter( ELMC_MCA_ID, slot + 1 );
				continue;
			}

			if( base_addr && base_addr !=
				csr_table[ (status & ELMC_STATUS_CSR_SELECT) >> 1]
			) {
				slot = mca_find_adapter( ELMC_MCA_ID, slot + 1 );
				continue;
			}
		}

		/* found what we're looking for... */
		break;
	}

	/* we didn't find any 3c523 in the slots we checked for */
	if( slot == MCA_NOTFOUND ) {
		return ((base_addr || irq) ? ENXIO : ENODEV);
	}

	mca_set_adapter_name( slot, "3Com 3c523 Etherlink/MC" );
	mca_set_adapter_procfn( slot, (MCA_ProcFn) elmc_getinfo, dev );

    /* if we get this far, adapter has been found - carry on */
    printk("%s: 3c523 adapter found in slot %d\n", dev->name, slot + 1);

    /* Now we extract configuration info from the card.
	The 3c523 provides information in two of the POS registers, but
	the second one is only needed if we want to tell the card what IRQ
	to use.  I suspect that whoever sets the thing up initially would
	prefer we don't screw with those things.

	Note we we read the status info when we found the card...

	See 3c523.h for more details.
	*/

    /* revision is stored in the first 4 bits of the revision register */
    revision = inb( dev->base_addr + ELMC_REVISION ) & 0xf;

    /* figure out our irq */
    dev->irq = irq_table[ (status & ELMC_STATUS_IRQ_SELECT) >> 6];

    /* according to docs, we read the interrupt and write it back to
    the IRQ select register, since the POST might not configure the IRQ
    properly. */
    switch( dev->irq ) {
    	case 3:
    		mca_write_pos( slot, 3, 0x04 );
    		break;
    	case 7:
    		mca_write_pos( slot, 3, 0x02 );
    		break;
    	case 9:
    		mca_write_pos( slot, 3, 0x08 );
    		break;
    	case 12:
    		mca_write_pos( slot, 3, 0x01 );
    		break;
    }

    /* Our IO address? */
    dev->base_addr = csr_table[ (status & ELMC_STATUS_CSR_SELECT) >> 1];

    request_region( dev->base_addr, ELMC_IO_EXTENT,"3c523");

    dev->priv = (void *) kmalloc(sizeof(struct priv),GFP_KERNEL);
    if (dev->priv == NULL) {
	return -ENOMEM;
    }
    memset((char *) dev->priv,0,sizeof(struct priv));

    ((struct priv *) (dev->priv))->slot = slot;

    printk("%s: 3Com 3c523 Rev 0x%x at %#lx\n", dev->name, (int) revision,
    	dev->base_addr);

    /* Determine if we're using the on-board transceiver (i.e. coax) or
        an external one.  The information is pretty much useless, but I
        guess it's worth brownie points. */
    dev->if_port = (status & ELMC_STATUS_DISABLE_THIN);

    /* The 3c523 has a 24K chunk of memory.  The first 16K is the
        shared memory, while the last 8K is for the EtherStart BIOS ROM.
        Which we don't care much about here.  We'll just tell Linux that
        we're using 16K.  MCA won't permit adress space conflicts caused
        by not mapping the other 8K. */
    dev->mem_start = shm_table[ (status & ELMC_STATUS_MEMORY_SELECT) >> 3];

  /* We're using MCA, so it's a given that the information about memory
  	size is correct.  The Crynwr drivers do something like this. */

  elmc_id_reset586();	/* seems like a good idea before checking it... */

  size = 0x4000; /* check for 16K mem */
  if(!check586(dev,(char *) dev->mem_start,size)) {
	printk("%s: memprobe, Can't find memory at 0x%lx!\n", dev->name,
		dev->mem_start );
	release_region( dev->base_addr, ELMC_IO_EXTENT );
	return ENODEV;
  }
  dev->mem_end = dev->mem_start + size; /* set mem_end showed by 'ifconfig' */

  ((struct priv *) (dev->priv))->base =  dev->mem_start + size - 0x01000000;
  alloc586(dev);

  elmc_id_reset586();	/* make sure it doesn't generate spurious ints */

  /* set number of receive-buffs according to memsize */
  ((struct priv *) dev->priv)->num_recv_buffs = NUM_RECV_BUFFS_16;

  /* dump all the assorted information */
  printk("%s: IRQ %d, %sternal xcvr, memory %#lx-%#lx.\n", dev->name,
  	dev->irq, dev->if_port ? "ex" : "in", dev->mem_start, dev->mem_end-1);

  /* The hardware address for the 3c523 is stored in the first six
  	bytes of the IO address. */
  printk( "%s: hardware address ", dev->name );
  for (i = 0; i < 6; i ++ ) {
   dev->dev_addr[i] = inb(dev->base_addr + i);
   printk(" %02x", dev->dev_addr[i]);
  }
  printk( "\n" );

  dev->open            = &elmc_open;
  dev->stop            = &elmc_close;
  dev->get_stats       = &elmc_get_stats;
  dev->hard_start_xmit = &elmc_send_packet;
  dev->set_multicast_list = &set_multicast_list;

  ether_setup(dev);

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

  /* note that we haven't actually requested the IRQ from the kernel.
  That gets done in elmc_open().  I'm not sure that's such a good idea,
  but it works, so I'll go with it. */

  return 0;
}

/**********************************************
 * init the chip (elmc-interrupt should be disabled?!)
 * needs a correct 'allocated' memory
 */

static
int
init586(struct device *dev) {
  void *ptr;
  unsigned long s;
  int i,result=0;
  struct priv *p = (struct priv *) dev->priv;
  volatile struct configure_cmd_struct  *cfg_cmd;
  volatile struct iasetup_cmd_struct *ias_cmd;
  volatile struct tdr_cmd_struct *tdr_cmd;
  volatile struct mcsetup_cmd_struct *mc_cmd;
  struct dev_mc_list *dmi=dev->mc_list;
  int num_addrs=dev->mc_count;

  ptr = (void *) ((char *)p->scb + sizeof(struct scb_struct));

  cfg_cmd = (struct configure_cmd_struct *)ptr; /* configure-command */
  cfg_cmd->cmd_status = 0;
  cfg_cmd->cmd_cmd    = CMD_CONFIGURE | CMD_LAST;
  cfg_cmd->cmd_link   = 0xffff;

  cfg_cmd->byte_cnt   = 0x0a; /* number of cfg bytes */
  cfg_cmd->fifo       = 0x08; /* fifo-limit (8=tx:32/rx:64) */
  cfg_cmd->sav_bf     = 0x40; /* hold or discard bad recv frames (bit 7) */
  cfg_cmd->adr_len    = 0x2e; /* addr_len |!src_insert |pre-len |loopback */
  cfg_cmd->priority   = 0x00;
  cfg_cmd->ifs        = 0x60;
  cfg_cmd->time_low   = 0x00;
  cfg_cmd->time_high  = 0xf2;
  cfg_cmd->promisc    = 0;
  if(dev->flags&(IFF_ALLMULTI|IFF_PROMISC))
  {
	cfg_cmd->promisc=1;
	dev->flags|=IFF_PROMISC;
  }
  cfg_cmd->carr_coll  = 0x00;

  p->scb->cbl_offset = make16(cfg_cmd);

  p->scb->cmd = CUC_START; /* cmd.-unit start */
  elmc_id_attn586();

  s = jiffies; /* warning: only active with interrupts on !! */
  while(!(cfg_cmd->cmd_status & STAT_COMPL)) {
    if(jiffies-s > 30) break;
  }

  if((cfg_cmd->cmd_status & (STAT_OK|STAT_COMPL)) != (STAT_COMPL|STAT_OK)) {
    printk("%s (elmc): configure command failed: %x\n",dev->name,cfg_cmd->cmd_status);
    return 1;
  }

    /*
     * individual address setup
     */
  ias_cmd = (struct iasetup_cmd_struct *)ptr;

  ias_cmd->cmd_status = 0;
  ias_cmd->cmd_cmd    = CMD_IASETUP | CMD_LAST;
  ias_cmd->cmd_link   = 0xffff;

  memcpy((char *)&ias_cmd->iaddr,(char *) dev->dev_addr,ETH_ALEN);

  p->scb->cbl_offset = make16(ias_cmd);

  p->scb->cmd = CUC_START; /* cmd.-unit start */
  elmc_id_attn586();

  s = jiffies;
  while(!(ias_cmd->cmd_status & STAT_COMPL))  {
    if(jiffies-s > 30) break;
  }

  if((ias_cmd->cmd_status & (STAT_OK|STAT_COMPL)) != (STAT_OK|STAT_COMPL)) {
    printk("%s (elmc): individual address setup command failed: %04x\n",dev->name,ias_cmd->cmd_status);
    return 1;
  }

   /*
    * TDR, wire check .. e.g. no resistor e.t.c
    */
  tdr_cmd = (struct tdr_cmd_struct *)ptr;

  tdr_cmd->cmd_status  = 0;
  tdr_cmd->cmd_cmd     = CMD_TDR | CMD_LAST;
  tdr_cmd->cmd_link    = 0xffff;
  tdr_cmd->status      = 0;

  p->scb->cbl_offset = make16(tdr_cmd);

  p->scb->cmd = CUC_START; /* cmd.-unit start */
  elmc_attn586();

  s = jiffies;
  while(!(tdr_cmd->cmd_status & STAT_COMPL)) {
    if(jiffies - s > 30) {
      printk("%s: %d Problems while running the TDR.\n",dev->name,__LINE__);
      result = 1;
      break;
    }
  }

  if(!result) {
    DELAY(2); /* wait for result */
    result = tdr_cmd->status;

    p->scb->cmd = p->scb->status & STAT_MASK;
    elmc_id_attn586(); /* ack the interrupts */

    if(result & TDR_LNK_OK) {
    	/* empty */
    } else if(result & TDR_XCVR_PRB) {
      printk("%s: TDR: Transceiver problem!\n",dev->name);
    } else if(result & TDR_ET_OPN) {
      printk("%s: TDR: No correct termination %d clocks away.\n",dev->name,result & TDR_TIMEMASK);
    } else if(result & TDR_ET_SRT) {
      if (result & TDR_TIMEMASK) /* time == 0 -> strange :-) */
        printk("%s: TDR: Detected a short circuit %d clocks away.\n",dev->name,result & TDR_TIMEMASK);
    } else {
      printk("%s: TDR: Unknown status %04x\n",dev->name,result);
    }
  }

   /*
    * ack interrupts
    */
  p->scb->cmd = p->scb->status & STAT_MASK;
  elmc_id_attn586();

   /*
    * alloc nop/xmit-cmds
    */
#if (NUM_XMIT_BUFFS == 1)
  for(i=0;i<2;i++) {
    p->nop_cmds[i] = (struct nop_cmd_struct *)ptr;
    p->nop_cmds[i]->cmd_cmd    = CMD_NOP;
    p->nop_cmds[i]->cmd_status = 0;
    p->nop_cmds[i]->cmd_link   = make16((p->nop_cmds[i]));
    ptr = (char *) ptr + sizeof(struct nop_cmd_struct);
  }
  p->xmit_cmds[0] = (struct transmit_cmd_struct *)ptr; /* transmit cmd/buff 0 */
  ptr = (char *) ptr + sizeof(struct transmit_cmd_struct);
#else
  for(i=0;i<NUM_XMIT_BUFFS;i++) {
    p->nop_cmds[i] = (struct nop_cmd_struct *)ptr;
    p->nop_cmds[i]->cmd_cmd    = CMD_NOP;
    p->nop_cmds[i]->cmd_status = 0;
    p->nop_cmds[i]->cmd_link   = make16((p->nop_cmds[i]));
    ptr = (char *) ptr + sizeof(struct nop_cmd_struct);
    p->xmit_cmds[i] = (struct transmit_cmd_struct *)ptr; /*transmit cmd/buff 0*/
    ptr = (char *) ptr + sizeof(struct transmit_cmd_struct);
  }
#endif

  ptr = alloc_rfa(dev,(void *)ptr); /* init receive-frame-area */

  /*
   * Multicast setup
   */

  if(dev->mc_count) {
    /* I don't understand this: do we really need memory after the init? */
    int len = ((char *) p->iscp - (char *) ptr - 8) / 6;
    if(len <= 0) {
      printk("%s: Ooooops, no memory for MC-Setup!\n",dev->name);
    } else {
      if(len < num_addrs) {
        num_addrs = len;
        printk("%s: Sorry, can only apply %d MC-Address(es).\n",
	    dev->name, num_addrs);
      }
      mc_cmd = (struct mcsetup_cmd_struct *) ptr;
      mc_cmd->cmd_status = 0;
      mc_cmd->cmd_cmd = CMD_MCSETUP | CMD_LAST;
      mc_cmd->cmd_link = 0xffff;
      mc_cmd->mc_cnt = num_addrs * 6;
      for(i=0;i<num_addrs;i++) {
	    memcpy((char *) mc_cmd->mc_list[i], dmi->dmi_addr,6);
	    dmi=dmi->next;
      }
      p->scb->cbl_offset = make16(mc_cmd);
      p->scb->cmd = CUC_START;
      elmc_id_attn586();
      s = jiffies;
      while(!(mc_cmd->cmd_status & STAT_COMPL)) {
        if(jiffies - s > 30)
          break;
	  }
      if(!(mc_cmd->cmd_status & STAT_COMPL)) {
        printk("%s: Can't apply multicast-address-list.\n",dev->name);
	  }
    }
  }

  /*
   * alloc xmit-buffs / init xmit_cmds
   */
  for(i=0;i<NUM_XMIT_BUFFS;i++) {
    p->xmit_cbuffs[i] = (char *)ptr; /* char-buffs */
    ptr = (char *) ptr + XMIT_BUFF_SIZE;
    p->xmit_buffs[i] = (struct tbd_struct *)ptr; /* TBD */
    ptr = (char *) ptr + sizeof(struct tbd_struct);
    if((void *)ptr > (void *)p->iscp) {
      printk("%s: not enough shared-mem for your configuration!\n",dev->name);
      return 1;
    }
    memset((char *)(p->xmit_cmds[i]) ,0, sizeof(struct transmit_cmd_struct));
    memset((char *)(p->xmit_buffs[i]),0, sizeof(struct tbd_struct));
    p->xmit_cmds[i]->cmd_status = STAT_COMPL;
    p->xmit_cmds[i]->cmd_cmd = CMD_XMIT | CMD_INT;
    p->xmit_cmds[i]->tbd_offset = make16((p->xmit_buffs[i]));
    p->xmit_buffs[i]->next = 0xffff;
    p->xmit_buffs[i]->buffer = make24((p->xmit_cbuffs[i]));
  }

  p->xmit_count = 0;
  p->xmit_last  = 0;
#ifndef NO_NOPCOMMANDS
  p->nop_point  = 0;
#endif

   /*
    * 'start transmitter' (nop-loop)
    */
#ifndef NO_NOPCOMMANDS
  p->scb->cbl_offset = make16(p->nop_cmds[0]);
  p->scb->cmd = CUC_START;
  elmc_id_attn586();
  WAIT_4_SCB_CMD();
#else
  p->xmit_cmds[0]->cmd_link = 0xffff;
  p->xmit_cmds[0]->cmd_cmd  = CMD_XMIT | CMD_LAST | CMD_INT;
#endif

  return 0;
}

/******************************************************
 * This is a helper routine for elmc_rnr_int() and init586().
 * It sets up the Receive Frame Area (RFA).
 */

static
void*
alloc_rfa(struct device *dev,void *ptr) {
  volatile struct rfd_struct *rfd = (struct rfd_struct *)ptr;
  volatile struct rbd_struct *rbd;
  int i;
  struct priv *p = (struct priv *) dev->priv;

  memset((char *) rfd,0,sizeof(struct rfd_struct)*p->num_recv_buffs);
  p->rfd_first = rfd;

  for(i = 0; i < p->num_recv_buffs; i++) {
    rfd[i].next = make16(rfd + (i+1) % p->num_recv_buffs);
  }
  rfd[p->num_recv_buffs-1].last = RFD_SUSP;   /* RU suspend */

  ptr = (void *) (rfd + p->num_recv_buffs);

  rbd = (struct rbd_struct *) ptr;
  ptr = (void *) (rbd + p->num_recv_buffs);

   /* clr descriptors */
  memset((char *) rbd,0,sizeof(struct rbd_struct)*p->num_recv_buffs);

  for(i=0;i<p->num_recv_buffs;i++) {
    rbd[i].next = make16((rbd + (i+1) % p->num_recv_buffs));
    rbd[i].size = RECV_BUFF_SIZE;
    rbd[i].buffer = make24(ptr);
    ptr = (char *) ptr + RECV_BUFF_SIZE;
  }

  p->rfd_top  = p->rfd_first;
  p->rfd_last = p->rfd_first + p->num_recv_buffs - 1;

  p->scb->rfa_offset		= make16(p->rfd_first);
  p->rfd_first->rbd_offset	= make16(rbd);

  return ptr;
}


/**************************************************
 * Interrupt Handler ...
 */

static
void
elmc_interrupt(int irq, void *dev_id, struct pt_regs *reg_ptr) {
  struct device *dev = (struct device *) dev_id;
  unsigned short stat;
  struct priv *p;

  if (dev == NULL) {
    printk ("elmc-interrupt: irq %d for unknown device.\n",(int) -(((struct pt_regs *)reg_ptr)->orig_eax+2));
    return;
  } else if( !dev->start ) {
    /* The 3c523 has this habit of generating interrupts during the
    	reset.  I'm not sure if the ni52 has this same problem, but it's
    	really annoying if we haven't finished initializing it.  I was
    	hoping all the elmc_id_* commands would disable this, but I
    	might have missed a few. */

    elmc_id_attn586(); /* ack inter. and disable any more */
    return;
  } else if( !(ELMC_CTRL_INT & inb( dev->base_addr+ELMC_CTRL )) ) {
  	/* wasn't this device */
  	return;
  }

  /* reading ELMC_CTRL also clears the INT bit. */

  p = (struct priv *) dev->priv;

  dev->interrupt = 1;

  while((stat=p->scb->status & STAT_MASK)) {
    p->scb->cmd = stat;
    elmc_attn586(); /* ack inter. */

   if(stat & STAT_CX) {
      /* command with I-bit set complete */
      elmc_xmt_int(dev);
   }

   if(stat & STAT_FR) {
     /* received a frame */
     elmc_rcv_int(dev);
   }

#ifndef NO_NOPCOMMANDS
    if(stat & STAT_CNA) {
      /* CU went 'not ready' */
      if(dev->start) {
        printk("%s: oops! CU has left active state. stat: %04x/%04x.\n",dev->name,(int) stat,(int) p->scb->status);
	  }
    }
#endif

    if(stat & STAT_RNR) {
      /* RU went 'not ready' */

      if(p->scb->status & RU_SUSPEND) {
        /* special case: RU_SUSPEND */

        WAIT_4_SCB_CMD();
        p->scb->cmd = RUC_RESUME;
        elmc_attn586();
      } else {
        printk("%s: Receiver-Unit went 'NOT READY': %04x/%04x.\n",dev->name,(int) stat,(int) p->scb->status);
        elmc_rnr_int(dev);
      }
    }
    WAIT_4_SCB_CMD(); /* wait for ack. (elmc_xmt_int can be faster than ack!!) */
    if(p->scb->cmd) {  /* timed out? */
      break;
    }
  }

  dev->interrupt = 0;
}

/*******************************************************
 * receive-interrupt
 */

static
void
elmc_rcv_int(struct device *dev) {
  int status;
  unsigned short totlen;
  struct sk_buff *skb;
  struct rbd_struct *rbd;
  struct priv *p = (struct priv *) dev->priv;

  for(;(status = p->rfd_top->status) & STAT_COMPL;) {
      rbd = (struct rbd_struct *) make32(p->rfd_top->rbd_offset);

      if(status & STAT_OK) /* frame received without error? */
      {
        if( (totlen = rbd->status) & RBD_LAST) /* the first and the last buffer? */
        {
          totlen &= RBD_MASK; /* length of this frame */
          rbd->status = 0;
          skb = (struct sk_buff *) dev_alloc_skb(totlen+2);
          if(skb != NULL) {
             skb->dev = dev;
            skb_reserve(skb,2);		/* 16 byte alignment */
            memcpy(skb_put(skb,totlen),(char *) p->base+(unsigned long) rbd->buffer, totlen);
            skb->protocol=eth_type_trans(skb,dev);
            netif_rx(skb);
            p->stats.rx_packets++;
            p->stats.rx_bytes+=totlen;
          } else {
            p->stats.rx_dropped++;
		  }
        } else {
          printk("%s: received oversized frame.\n",dev->name);
          p->stats.rx_dropped++;
        }
      } else /* frame !(ok), only with 'save-bad-frames' */ {
        printk("%s: oops! rfd-error-status: %04x\n",dev->name,status);
        p->stats.rx_errors++;
      }
      p->rfd_top->status = 0;
      p->rfd_top->last = RFD_SUSP;
      p->rfd_last->last = 0;        /* delete RU_SUSP  */
      p->rfd_last = p->rfd_top;
      p->rfd_top = (struct rfd_struct *) make32(p->rfd_top->next); /* step to next RFD */
  }
}

/**********************************************************
 * handle 'Receiver went not ready'.
 */

static
void
elmc_rnr_int(struct device *dev) {
  struct priv *p = (struct priv *) dev->priv;

  p->stats.rx_errors++;

  WAIT_4_SCB_CMD();    /* wait for the last cmd */
  p->scb->cmd = RUC_ABORT; /* usually the RU is in the 'no resource'-state .. abort it now. */
  elmc_attn586();
  WAIT_4_SCB_CMD();    /* wait for accept cmd. */

  alloc_rfa(dev,(char *)p->rfd_first);
  startrecv586(dev); /* restart RU */

  printk("%s: Receive-Unit restarted. Status: %04x\n",dev->name,p->scb->status);

}

/**********************************************************
 * handle xmit - interrupt
 */

static
void
elmc_xmt_int(struct device *dev) {
  int status;
  struct priv *p = (struct priv *) dev->priv;

  status = p->xmit_cmds[p->xmit_last]->cmd_status;
  if(!(status & STAT_COMPL)) {
    printk("%s: strange .. xmit-int without a 'COMPLETE'\n",dev->name);
  }

  if(status & STAT_OK) {
    p->stats.tx_packets++;
    p->stats.collisions += (status & TCMD_MAXCOLLMASK);
  } else {
    p->stats.tx_errors++;
    if(status & TCMD_LATECOLL) {
      printk("%s: late collision detected.\n",dev->name);
      p->stats.collisions++;
    } else if(status & TCMD_NOCARRIER) {
      p->stats.tx_carrier_errors++;
      printk("%s: no carrier detected.\n",dev->name);
    } else if(status & TCMD_LOSTCTS) {
      printk("%s: loss of CTS detected.\n",dev->name);
    } else if(status & TCMD_UNDERRUN) {
      p->stats.tx_fifo_errors++;
      printk("%s: DMA underrun detected.\n",dev->name);
    } else if(status & TCMD_MAXCOLL) {
      printk("%s: Max. collisions exceeded.\n",dev->name);
      p->stats.collisions += 16;
    }
  }

#if (NUM_XMIT_BUFFS != 1)
  if( (++p->xmit_last) == NUM_XMIT_BUFFS) {
    p->xmit_last = 0;
  }
#endif

  dev->tbusy = 0;
  mark_bh(NET_BH);
}

/***********************************************************
 * (re)start the receiver
 */

static
void
startrecv586(struct device *dev)
{
  struct priv *p = (struct priv *) dev->priv;

  p->scb->rfa_offset = make16(p->rfd_first);
  p->scb->cmd = RUC_START;
  elmc_attn586();		/* start cmd. */
  WAIT_4_SCB_CMD();	/* wait for accept cmd. (no timeout!!) */
}

/******************************************************
 * send frame
 */

static
int
elmc_send_packet(struct sk_buff *skb, struct device *dev)
{
  int len;
#ifndef NO_NOPCOMMANDS
  int next_nop;
#endif
  struct priv *p = (struct priv *) dev->priv;

  if(dev->tbusy) {
    int tickssofar = jiffies - dev->trans_start;
    if (tickssofar < 5) {
      return 1;
    }

    /* COMMAND-UNIT active? */
    if(p->scb->status & CU_ACTIVE) {
      dev->tbusy = 0;
#ifdef DEBUG
      printk("%s: strange ... timeout with CU active?!?\n",dev->name);
      printk("%s: X0: %04x N0: %04x N1: %04x %d\n",dev->name,(int)p->xmit_cmds[0]->cmd_status,(int)p->nop_cmds[0]->cmd_status,(int)p->nop_cmds[1]->cmd_status,(int)p->nop_point);
#endif
      p->scb->cmd = CUC_ABORT;
      elmc_attn586();
      WAIT_4_SCB_CMD();
      p->scb->cbl_offset = make16(p->nop_cmds[p->nop_point]);
      p->scb->cmd = CUC_START;
      elmc_attn586();
      WAIT_4_SCB_CMD();
      dev->trans_start = jiffies;
      return 0;
    } else {
#ifdef DEBUG
      printk("%s: xmitter timed out, try to restart! stat: %04x\n",dev->name,p->scb->status);
      printk("%s: command-stats: %04x %04x\n",dev->name,p->xmit_cmds[0]->cmd_status,p->xmit_cmds[1]->cmd_status);
#endif
      elmc_close(dev);
      elmc_open(dev);
    }
    dev->trans_start = jiffies;
    return 0;
  }

  if (test_and_set_bit(0, (void*)&dev->tbusy) != 0) {
     printk("%s: Transmitter access conflict.\n", dev->name);
  } else {
    memcpy((char *)p->xmit_cbuffs[p->xmit_count],(char *)(skb->data),skb->len);
    len = (ETH_ZLEN < skb->len) ? skb->len : ETH_ZLEN;

#if (NUM_XMIT_BUFFS == 1)
#  ifdef NO_NOPCOMMANDS
    p->xmit_buffs[0]->size = TBD_LAST | len;
    for(i=0;i<16;i++) {
      p->scb->cbl_offset = make16(p->xmit_cmds[0]);
      p->scb->cmd = CUC_START;
      p->xmit_cmds[0]->cmd_status = 0;

      elmc_attn586();
      dev->trans_start = jiffies;
      if(!i) {
        dev_kfree_skb(skb);
	  }
      WAIT_4_SCB_CMD();
      if( (p->scb->status & CU_ACTIVE)) /* test it, because CU sometimes doesn't start immediately */
      {
        break;
      }
      if(p->xmit_cmds[0]->cmd_status) {
        break;
	  }
      if(i==15) {
        printk("%s: Can't start transmit-command.\n",dev->name);
	  }
    }
#  else
    next_nop = (p->nop_point + 1) & 0x1;
    p->xmit_buffs[0]->size = TBD_LAST | len;

    p->xmit_cmds[0]->cmd_link   = p->nop_cmds[next_nop]->cmd_link
                                = make16((p->nop_cmds[next_nop]));
    p->xmit_cmds[0]->cmd_status = p->nop_cmds[next_nop]->cmd_status = 0;

    p->nop_cmds[p->nop_point]->cmd_link = make16((p->xmit_cmds[0]));
    dev->trans_start = jiffies;
    p->nop_point = next_nop;
    dev_kfree_skb(skb);
#  endif
#else
    p->xmit_buffs[p->xmit_count]->size = TBD_LAST | len;
    if( (next_nop = p->xmit_count + 1) == NUM_XMIT_BUFFS ) {
      next_nop = 0;
    }

    p->xmit_cmds[p->xmit_count]->cmd_status  = 0;
    p->xmit_cmds[p->xmit_count]->cmd_link = p->nop_cmds[next_nop]->cmd_link
                                          = make16((p->nop_cmds[next_nop]));
    p->nop_cmds[next_nop]->cmd_status = 0;

    p->nop_cmds[p->xmit_count]->cmd_link = make16((p->xmit_cmds[p->xmit_count]));
    dev->trans_start = jiffies;
    p->xmit_count = next_nop;

    cli();
    if(p->xmit_count != p->xmit_last) {
      dev->tbusy = 0;
    }
    sti();
    dev_kfree_skb(skb);
#endif
  }
  return 0;
}

/*******************************************
 * Someone wanna have the statistics
 */

static struct net_device_stats *elmc_get_stats( struct device *dev ) 
{
  struct priv *p = (struct priv *) dev->priv;
  unsigned short crc,aln,rsc,ovrn;

  crc = p->scb->crc_errs; /* get error-statistic from the ni82586 */
  p->scb->crc_errs -= crc;
  aln = p->scb->aln_errs;
  p->scb->aln_errs -= aln;
  rsc = p->scb->rsc_errs;
  p->scb->rsc_errs -= rsc;
  ovrn = p->scb->ovrn_errs;
  p->scb->ovrn_errs -= ovrn;

  p->stats.rx_crc_errors += crc;
  p->stats.rx_fifo_errors += ovrn;
  p->stats.rx_frame_errors += aln;
  p->stats.rx_dropped += rsc;

  return &p->stats;
}

/********************************************************
 * Set MC list ..
 */

static
void
set_multicast_list(struct device *dev) {
  if(!dev->start) {
    /* without a running interface, promiscuous doesn't work */
    return;
  }

  dev->start = 0;
  alloc586(dev);
  init586(dev);
  startrecv586(dev);
  dev->start = 1;
}

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

#ifdef MODULE
static struct device dev_elmc = {
	"        " /*"3c523"*/, 0, 0, 0, 0, 0, 0, 0, 0, 0, NULL, elmc_probe };

static int irq=0;
static int io=0;
MODULE_PARM(irq, "i");
MODULE_PARM(io, "i");

int
init_module(void) {
	struct device *dev = &dev_elmc;

	dev->base_addr=io;
	dev->irq=irq;
	if (register_netdev(dev) != 0) {
		return -EIO;
	}

	return 0;
}

void
cleanup_module(void) {
	struct device *dev = &dev_elmc;

	if (MOD_IN_USE) {
		printk("3c523: device busy, remove delayed\n");
	} else {
  		/* shutdown interrupts on the card */
		elmc_id_reset586();

  		if( dev->irq != 0 ) {
	      /* this should be done by close, but if we failed to
	      initialize properly something may have gotten hosed. */
	      free_irq( dev->irq, dev );
	      dev->irq = 0;
	    }



		if( dev->base_addr != 0 ) {
	  	  release_region( dev->base_addr, ELMC_IO_EXTENT );
		  dev->base_addr = 0;
		}
		irq = 0;
		io = 0;

		unregister_netdev(dev);

    		mca_set_adapter_procfn( ((struct priv *) (dev->priv))->slot,
    			NULL, NULL );

		kfree_s(dev->priv,sizeof(struct priv));
		dev->priv=NULL;
	}
}
#endif /* MODULE */