/*  depca.c: A DIGITAL DEPCA ethernet driver for linux.

    Written 1994 by David C. Davies.

    Copyright 1994 David C. Davies and United States Government as
    represented by the Director, National Security Agency.  This software
    may be used and distributed according to the terms of the GNU Public
    License, incorporated herein by reference.

    This driver is written for the Digital Equipment Corporation series
    of DEPCA ethernet cards:

    	DE100 DEPCA
	DE200 DEPCA Turbo
	DE202 DEPCA Turbo (TP BNC)
	DE210 DEPCA

    The driver has been tested on DE100 and DE20x cards in a relatively busy 
    network.

    The author may be reached as davies@wanton.enet.dec.com or
    Digital Equipment Corporation, 146 Main Street, Maynard MA 01754.

    =========================================================================
    The driver was based on the 'lance.c' driver from Donald Becker which is
    included with the standard driver distribution for linux. Modifications
    were made to most routines and the hardware recognition routines were
    written from scratch. Primary references used were:

    1) Lance.c code in /linux/drivers/net/
    2) "Ethernet/IEEE 802.3 Family. 1992 World Network Data Book/Handbook",
       AMD, 1992 [(800) 222-9323].
    3) "Am79C90 CMOS Local Area Network Controller for Ethernet (C-LANCE)",
       AMD, Pub. #17881, May 1993.
    4) "Am79C960 PCnet-ISA(tm), Single-Chip Ethernet Controller for ISA",
       AMD, Pub. #16907, May 1992
    5) "DEC EtherWORKS LC Ethernet Controller Owners Manual",
       Digital Equipment corporation, 1990, Pub. #EK-DE100-OM.003
    6) "DEC EtherWORKS Turbo Ethernet Controller Owners Manual",
       Digital Equipment corporation, 1990, Pub. #EK-DE200-OM.003
    7) "DEPCA Hardware Reference Manual", Pub. #EK-DEPCA-PR
       Digital Equipment Corporation, 1989
    8) "DEC EtherWORKS Turbo_(TP BNC) Ethernet Controller Owners Manual",
       Digital Equipment corporation, 1991, Pub. #EK-DE202-OM.001
    
    Peter Bauer's depca.c (V0.5) was referred to when debugging this driver.
    The hash filter code was  derived from Reference  3 and has been  tested
    only to the extent that the Table  A-1, page A-7,  was confirmed to fill
    the   filter bit   positions  correctly.  Hash   filtering  is  not  yet
    implemented in the current driver set.

    The  DE200 series boards have   on-board 64kB RAM  for  use as a  shared
    memory network buffer. Only  the DE100 cards  make  use of a  2kB buffer
    mode  which has not  been implemented in  this driver (only the 32kB and
    64kB modes are supported).

    At the  most only 2 DEPCA  cards can be supported  because there is only
    provision for two I/O base addresses on the cards (0x300 and 0x200). The
    base  address is  'autoprobed' by  looking  for  the self  test PROM and
    detecting the  card name.  The shared memory  base address is decoded by
    'autoprobing' the Ethernet PROM address information. The second DEPCA is
    detected and information placed  in the base_addr  variable of the  next
    device  structure   (which is created    if  necessary),  thus  enabling
    ethif_probe initialization for the device.

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

    NOTE: If you are using two  DEPCAs, it is important  that you assign the
    base memory addresses  correctly.  The driver  autoprobes I/O 0x300 then
    0x200.  The base memory  address for the  first device must be less than
    that of the second so that the auto probe will  correctly assign the I/O
    and  memory addresses on  the same card.  I can't  think of  a way to do
    this unambiguously at the moment, since there is nothing on the cards to
    tie I/O and memory information together.

    I   am unable to test    2 DEPCAs together for   now,   so this code  is
    unchecked. All reports, good or bad, are welcome.

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

    The board IRQ  setting must be  at  an unused  IRQ  which is auto-probed
    using   Donald Becker's   autoprobe   routines. DE100   board IRQs   are
    {2,3,4,5,7}, whereas  the DE200 is at  {5,9,10,11,15}. Note that IRQ2 is
    really IRQ9 in machines with 16 IRQ lines.

    No 16MB memory  limitation should exist with this  driver as DMA is  not
    used and the common memory area is in low memory on the network card (my
    current system has 20MB and I've not had problems yet).

    The DE203,  DE204  and DE205 cards  may  also work  with this driver  (I
    haven't tested  them so I don't  know). If you have  one of these cards,
    place the name in the DEPCA_SIGNATURE string  around line 160, recompile
    the kernel and reboot. Check if the card  is recognised and works - mail
    me if so, so that I can add it into the list of supported cards!

    TO DO:
    ------

    1. Implement the 2k buffer mode - does anyone need it??

    Revision History
    ----------------

    Version   Date        Description
  
      0.1   25-jan-94     Initial writing
      0.2   27-jan-94     Added LANCE TX buffer chaining
      0.3    1-feb-94     Added multiple DEPCA support
      0.31   4-feb-94     Added DE202 recognition
      0.32  19-feb-94     Tidy up. Improve multi-DEPCA support.

    =========================================================================
*/

static char *version = "depca.c:v0.32 2/19/94 davies@wanton.enet.dec.com\n";

#include <stdarg.h>
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/malloc.h>
#include <linux/interrupt.h>
#include <asm/bitops.h>
#include <asm/io.h>
#include <asm/dma.h>

#include "dev.h"
#include "iow.h"
#include "eth.h"
#include "skbuff.h"
#include "arp.h"
#include "depca.h"

#ifdef DEPCA_DEBUG
int depca_debug = DEPCA_DEBUG;
#else
int depca_debug = 1;
#endif

#ifndef DEPCA_IRQ
/*#define DEPCA_IRQ	{5,9,10,11,15,0}*/
#define DEPCA_IRQ	5
#endif

#ifndef PROBE_LENGTH
#define PROBE_LENGTH    32
#endif

#ifndef PROBE_SEQUENCE
#define PROBE_SEQUENCE "FF0055AAFF0055AA"
#endif

#ifndef DEPCA_SIGNATURE
#define DEPCA_SIGNATURE {"DEPCA","DE100","DE200","DE202","DE210",""}
#define DEPCA_NAME_LENGTH 8
#endif

#ifndef DEPCA_RAM_BASE_ADDRESSES
#define DEPCA_RAM_BASE_ADDRESSES {0xc0000,0xd0000,0xe0000,0x00000}
#endif
static short mem_chkd = 0;               /* holds which base addrs have been */
					 /* checked, for multi-DEPCA case */

#ifndef DEPCA_IO_PORTS
#define DEPCA_IO_PORTS {0x300, 0x200, 0}
#endif

#ifndef DEPCA_TOTAL_SIZE
#define DEPCA_TOTAL_SIZE 0x10
#endif

#ifndef MAX_NUM_DEPCAS
#define MAX_NUM_DEPCAS 2
#endif

/*
** Set the number of Tx and Rx buffers. 
*/
#ifndef DEPCA_BUFFER_LOG_SZ
#define RING_SIZE	16              /* 16 buffers */
#else
#define RING_SIZE	(1 << (DEPCA_BUFFERS_LOG_SZ))
#endif  /* DEPCA_BUFFER_LOG_SZ */

#define PKT_BUF_SZ	1544            /* Buffer size for each Tx/Rx buffer */
#define PKT_SZ   	1514            /* Maximum ethernet packet length */
#define DAT_SZ   	1500            /* Maximum ethernet data length */
#define PKT_HDR_LEN     14              /* Addresses and data length info */

#ifdef HAVE_MULTICAST
#ifndef CRC_POLYNOMIAL
#define CRC_POLYNOMIAL 0x04c11db7       /* Ethernet CRC polynomial */
#endif /* CRC_POLYNOMIAL */
#endif /* HAVE_MULTICAST */

#ifndef HAVE_ALLOC_SKB
#define alloc_skb(size, priority) (struct sk_buff *) kmalloc(size,priority)
#define kfree_skbmem(buff, size) kfree_s(buff,size)
#endif  /* HAVE_ALLOC_SKB */

/*
** The DEPCA Rx and Tx ring descriptors. 
*/
struct depca_rx_head {
    long base;
    short buf_length;		/* This length is negative 2's complement! */
    short msg_length;		/* This length is "normal". */
};

struct depca_tx_head {
    long base;
    short length;		/* This length is negative 2's complement! */
    short misc;                 /* Errors and TDR info */
};

struct depca_ring_info {
};

/*
** The Lance initialization block, described in databook, in common memory.
*/
struct depca_init {
    unsigned short mode;	/* Mode register */
    unsigned char phys_addr[ETH_ALEN];	/* Physical ethernet address */
    unsigned short filter[4];	/* Multicast filter. */
    unsigned long rx_ring;     	/* Rx ring base pointer & ring length */
    unsigned long tx_ring;	/* Tx ring base pointer & ring length */
};

struct depca_private {
    char devname[8];            /* Not used */
    struct depca_rx_head *rx_ring; /* Pointer to start of RX descriptor ring */
    struct depca_tx_head *tx_ring; /* Pointer to start of TX descriptor ring */
    struct depca_init	init_block;/* Initialization block */
    long dma_buffs;		/* Start address of Rx and Tx buffers. */
    int	cur_rx, cur_tx;		/* The next free ring entry */
    int dirty_rx, dirty_tx;	/* The ring entries to be free()ed. */
    int dma;
    struct enet_statistics stats;
    char old_depca;
    short ringSize;             /* ring size based on available memory */
    short rmask;                /* modulus mask based on ring size */
    long rlen;                  /* log2(ringSize) for the descriptors */
};

/*
** Public Functions
*/
static int depca_open(struct device *dev);
static int depca_start_xmit(struct sk_buff *skb, struct device *dev);
static void depca_interrupt(int reg_ptr);
static int depca_close(struct device *dev);
static struct enet_statistics *depca_get_stats(struct device *dev);
#ifdef HAVE_MULTICAST
static void set_multicast_list(struct device *dev, int num_addrs, void *addrs);
#endif

/*
** Private functions
*/
static int depca_probe1(struct device *dev, short ioaddr);
static void depca_init_ring(struct device *dev);
static int depca_rx(struct device *dev);
static int depca_tx(struct device *dev);

static void LoadCSRs(struct device *dev);
static int InitRestartDepca(struct device *dev);
static char *DepcaSignature(unsigned long mem_addr);
static int DevicePresent(short ioaddr);
#ifdef HAVE_MULTICAST
static void SetMulticastFilter(int num_addrs, char *addrs, char *multicast_table);
#endif

static int num_depcas = 0, num_eth = 0;;

/*
** Miscellaneous defines...
*/
#define STOP_DEPCA \
    outw(CSR0, DEPCA_ADDR);\
    outw(STOP, DEPCA_DATA)



int depca_probe(struct device *dev)
{
    int *port, ports[] = DEPCA_IO_PORTS;
    int base_addr = dev->base_addr;
    int status;
    struct device *eth0 = (struct device *) NULL;

    if (base_addr > 0x1ff) {	      /* Check a single specified location. */
		status = depca_probe1(dev, base_addr);
    } else if (base_addr > 0) {	      /* Don't probe at all. */
		status = -ENXIO;
    } else {                          /* First probe for the DEPCA test */
                                      /* pattern in ROM */

      for (status = -ENODEV, port = &ports[0]; 
	                    *port && (num_depcas < MAX_NUM_DEPCAS); port++) {
	int ioaddr = *port;

#ifdef HAVE_PORTRESERVE
	if (check_region(ioaddr, DEPCA_TOTAL_SIZE))
	    continue;
#endif
	if (DevicePresent(DEPCA_PROM) == 0) {
	  if (num_depcas > 0) {        /* only gets here in autoprobe */

	    /*
	    ** Check the device structures for an end of list or unused device
	    */
	    while (dev->next != (struct device *)NULL) {
	      if (dev->next->base_addr == 0xffe0) break;
	      dev = dev->next;         /* walk through eth device list */
	      num_eth++;               /* increment eth device number */
	    }

	    /*
	    ** If no more device structures, malloc one up. If memory could
	    ** not be allocated, print an error message.
	    ** 
	    */
	    if (dev->next == (struct device *)NULL) {
	      dev->next = (struct device *)kmalloc(sizeof(struct device) + 8,
                                                                  GFP_KERNEL);
	    } else {
	      printk("eth%d: Device not initialised, insufficient memory\n",
		                                                      num_eth);
	    }

	    /*
	    ** If the memory was allocated, point to the new memory area
	    ** and initialize it (name, I/O address, next device (NULL) and
	    ** initialisation probe routine).
	    */
	    if ((dev->next != (struct device *)NULL) &&
		(num_eth > 0) && (num_eth < 9999)) {
	      dev = dev->next;         /* point to the new device */
	      dev->name = (char *)(dev + sizeof(struct device));
	      sprintf(dev->name,"eth%d", num_eth); /* New device name */
	      dev->base_addr = ioaddr; /* assign the io address */
	      dev->next = (struct device *)NULL; /* mark the end of list */
	      dev->init = &depca_probe;/* initialisation routine */
	    }
	  } else {
	    eth0 = dev;                /* remember the first device */
	    status = depca_probe1(dev, ioaddr);
	  }
	  num_depcas++;
	  num_eth++;
	}
      }
      if (eth0) dev = eth0;             /* restore the first device */
    }

    if (status) dev->base_addr = base_addr;

    return status;			/* ENODEV would be more accurate. */
}

static int
depca_probe1(struct device *dev, short ioaddr)
{
    struct depca_private *lp;
    int i,j, status=0;
    unsigned long mem_start, mem_base[] = DEPCA_RAM_BASE_ADDRESSES;
    char *name=(char *)NULL;
    int nicsr, offset;


    /*
    ** Stop the DEPCA. Enable the DBR ROM. Disable interrupts and remote boot
    */
    STOP_DEPCA;

    nicsr = inw(DEPCA_NICSR);
    nicsr = ((nicsr & ~SHE & ~RBE & ~IEN) | IM);
    outw(nicsr, DEPCA_NICSR);

    if (inw(DEPCA_DATA) == STOP) {

    /* Now find out what kind of DEPCA we have. The DE100 uses a different
    ** addressing scheme for some registers compared to the DE2xx series.
    ** Note that a base address location is marked as checked if no DEPCA is
    ** there or one is found (when the search is immediately terminated). This
    ** shortens the search time a little for multiple DEPCAs.
    */

      for (j = 0, i = 0; mem_base[i] && (j == 0);) {
	if (((mem_chkd >> i) & 0x01) == 0) { /* has the memory been checked? */
	  name = DepcaSignature(mem_base[i]);/* check for a DEPCA here */
	  mem_chkd |= (0x01 << i);           /* mark location checked */
	  if (*name != (char)NULL) {         /* one found? */
	    j = 1;                           /* set exit flag */
	  } else {
	    i++;                             /* increment search index */
	  }
	}
      }

      if (*name != (char)NULL) {          /* found a DEPCA device */
	mem_start = mem_base[i];
	dev->base_addr = ioaddr;

	printk("%s: DEPCA at %#3x is a %s, ", dev->name, ioaddr, name);

      /* There is a 32 byte station address PROM at DEPCA_PROM address.
	 The first six bytes are the station address. They can be read
	 directly since the signature search set up the ROM address 
	 counter correctly just before this function.

	 For the DE100 we have to be careful about which port is used to
	 read the ROM info.
      */

	if (strstr(name,"DE100")!=(char *)NULL) {
	  j = 1;
	} else {
	  j = 0;
	}

	printk("ethernet address ");
	for (i = 0; i < ETH_ALEN - 1; i++) { /* get the ethernet address */
	  printk("%2.2x:", dev->dev_addr[i] = inb(DEPCA_PROM + j));
	}
	printk("%2.2x", dev->dev_addr[i] = inb(DEPCA_PROM + j));

	for (;i<32;i++) {                /* leave ROM counter in known state */
	  j=inb(DEPCA_PROM);
	}

#ifdef HAVE_PORTRESERVE
	snarf_region(ioaddr, DEPCA_TOTAL_SIZE);
#endif

	/* 
	 ** Determine the base address for the DEPCA RAM from the NI-CSR
	 ** and make up a DEPCA-specific-data structure. 
        */

	if (nicsr & BUF) {
	  offset = 0x8000;              /* 32kbyte RAM */
	  nicsr &= ~BS;                 /* DEPCA RAM in top 32k */
	  printk(",\n      with 32kB RAM");
	} else {
	  offset = 0x0000;              /* 64kbyte RAM */
	  printk(",\n      with 64kB RAM");
	}

	mem_start += offset;
	printk(" starting at 0x%.5lx", mem_start);

	/*
	 ** Enable the shadow RAM.
	*/
	nicsr |= SHE;
	outw(nicsr, DEPCA_NICSR);
 
	/*
	** Calculate the ring size based on the available RAM
	** found above. Allocate an equal number of buffers, each
	** of size PKT_BUF_SZ (1544 bytes) to the Tx and Rx. Make sure
	** that this ring size is <= RING_SIZE. The ring size must be
	** a power of 2.
	*/

	j = ((0x10000 - offset) / PKT_BUF_SZ) >> 1;
	for (i=0;j>1;i++) {
	  j >>= 1;
	}

	/* Hold the ring size information here before the depca
	** private structure is allocated. Need this for the memory
	** space calculations.
	*/
	j = 1 << i;

	/*
	** Set up memory information in the device structure.
	** Align the descriptor rings on an 8 byte (quadword) boundary.
	**
	**     depca_private area
	**     rx ring descriptors
	**     tx ring descriptors
	**     rx buffers
	**     tx buffers
	**
	*/

	/* private area & initialise */
	dev->priv = (void *)((mem_start + 0x07) & ~0x07);      
	lp = (struct depca_private *)dev->priv;
	memset(dev->priv, 0, sizeof(struct depca_private));

	/* Tx & Rx descriptors (aligned to a quadword boundary) */
	mem_start = ((((unsigned long)dev->priv + 
		        sizeof(struct depca_private)) +
			(unsigned long)0x07) & (unsigned long)~0x07);
	lp->rx_ring = (struct depca_rx_head *)mem_start;

	mem_start += (sizeof(struct depca_rx_head) * j);
	lp->tx_ring = (struct depca_tx_head *)mem_start;

	mem_start += (sizeof(struct depca_tx_head) * j);
	lp->dma_buffs = mem_start & 0x00ffffff;

	mem_start += (PKT_BUF_SZ * j);
	/* (mem_start now points to the start of the Tx buffers) */

	/* Initialise the data structures */
	memset(lp->rx_ring, 0, sizeof(struct depca_rx_head)*j);
	memset(lp->tx_ring, 0, sizeof(struct depca_tx_head)*j);

	/* This should never happen. */
	if ((int)(lp->rx_ring) & 0x07) {
	  printk("\n **ERROR** DEPCA Rx and Tx descriptor rings not on a quadword boundary.\n");
	  return -ENXIO;
	}

	/*
	** Finish initialising the ring information.
	*/
	lp->ringSize = j;
	if (lp->ringSize > RING_SIZE) lp->ringSize = RING_SIZE;
	lp->rmask = lp->ringSize - 1;

	/*
	** calculate the real RLEN size for the descriptors. It is
	** log2(ringSize).
	*/
	for (i=0, j = lp->ringSize; j>1; i++) {
	  j >>= 1;
	}
	lp->rlen = (unsigned long)(i << 29);

	/*
	** load the initialisation block
	*/
	depca_init_ring(dev);

	/*
	** Initialise the control and status registers
	*/
	LoadCSRs(dev);

	/*
	** Enable DEPCA board interrupts for autoprobing
	*/
	nicsr = ((nicsr & ~IM)|IEN);
	outw(nicsr, DEPCA_NICSR);

	/* The DMA channel may be passed in on this parameter. */
	dev->dma = 0;
	
	/* To auto-IRQ we enable the initialization-done and DMA err,
	 interrupts. For now we will always get a DMA error. */
	if (dev->irq < 2) {
	  autoirq_setup(0);

	  /* Trigger an initialization just for the interrupt. */
	  outw(INEA | INIT, DEPCA_DATA);
	  
	  dev->irq = autoirq_report(1);
	  if (dev->irq) {
	    printk(" and probed IRQ%d.\n", dev->irq);
	  } else {
	    printk(". Failed to detect IRQ line.\n");
	    status = -EAGAIN;
	  }
	} else {
	  printk(". Assigned IRQ%d.\n", dev->irq);
	}
      } else {
	status = -ENXIO;
      }
      if (!status) {
	if (depca_debug > 0) {
	  printk(version);
	}

	/* The DEPCA-specific entries in the device structure. */
	dev->open = &depca_open;
	dev->hard_start_xmit = &depca_start_xmit;
	dev->stop = &depca_close;
	dev->get_stats = &depca_get_stats;
#ifdef HAVE_MULTICAST
	dev->set_multicast_list = &set_multicast_list;
#endif

	dev->mem_start = 0;
	
	/* Fill in the generic field of the device structure. */
	for (i = 0; i < DEV_NUMBUFFS; i++) {
	  dev->buffs[i] = NULL;
	}

	dev->hard_header     = eth_header;
	dev->add_arp	     = eth_add_arp;
	dev->queue_xmit	     = dev_queue_xmit;
	dev->rebuild_header  = eth_rebuild_header;
	dev->type_trans	     = eth_type_trans;
	
	dev->type	     = ARPHRD_ETHER;
	dev->hard_header_len = ETH_HLEN;
	dev->mtu	     = 1500; /* eth_mtu */
	dev->addr_len	     = ETH_ALEN;

	for (i = 0; i < dev->addr_len; i++) {
	  dev->broadcast[i]=0xff;
	}
	
	/* New-style flags. */
	dev->flags	     = IFF_BROADCAST;
	dev->family	     = AF_INET;
	dev->pa_addr	     = 0;
	dev->pa_brdaddr	     = 0;
	dev->pa_mask	     = 0;
	dev->pa_alen	     = sizeof(unsigned long);
      }
    } else {
      status = -ENXIO;
    }

    return status;
}

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

    if (request_irq(dev->irq, &depca_interrupt)) {
        printk("depca_open(): Requested IRQ%d is busy\n",dev->irq);
	return -EAGAIN;
    }

    irq2dev_map[dev->irq] = dev;

    /*
    ** Stop the DEPCA & get the board status information.  
    */
    STOP_DEPCA;
    nicsr = inw(DEPCA_NICSR);

    /* 
    ** Re-initialize the DEPCA... 
    */
    depca_init_ring(dev);                 /* initialize the descriptor rings */
    LoadCSRs(dev);

    if (depca_debug > 1){
      printk("%s: depca open with irq %d\n",dev->name,dev->irq);
      printk("Descriptor head addresses:\n");
      printk("\t0x%8.8lx  0x%8.8lx\n",(long)lp->rx_ring,(long)lp->tx_ring);
      printk("Descriptor addresses:\n");
      for (i=0;i<lp->ringSize;i++){
	printk("\t0x%8.8lx  0x%8.8lx\n",(long)&lp->rx_ring[i].base,
	                                (long)&lp->tx_ring[i].base);
      }
      printk("Buffer addresses:\n");
      for (i=0;i<lp->ringSize;i++){
	printk("\t0x%8.8lx  0x%8.8lx\n",(long)lp->rx_ring[i].base,
                                        (long)lp->tx_ring[i].base);
      }
      printk("Initialisation block at 0x%8.8lx\n",(long)&lp->init_block);
      printk("\tmode: 0x%4.4x\n",lp->init_block.mode);
      printk("\tphysical address: ");
      for (i=0;i<6;i++){
	printk("%2.2x:",(short)lp->init_block.phys_addr[i]);
      }
      printk("\n\tlogical address filter: 0x");
      for (i=0;i<4;i++){
	printk("%2.2x",(short)lp->init_block.filter[i]);
      }
      printk("\n\trx_ring at: 0x%8.8lx\n",(long)lp->init_block.rx_ring);
      printk("\ttx_ring at: 0x%8.8lx\n",(long)lp->init_block.tx_ring);
      printk("dma_buffs: 0x%8.8lx\n",(long)lp->dma_buffs);
      printk("Ring size: %d\nMask: 0x%2.2x\nLog2(ringSize): 0x%8.8lx\n", 
                                         (short)lp->ringSize, 
                                          (char)lp->rmask,
                                          (long)lp->rlen);
      outw(CSR2,DEPCA_ADDR);
      printk("CSR2&1: 0x%4.4x",inw(DEPCA_DATA));
      outw(CSR1,DEPCA_ADDR);
      printk("%4.4x\n",inw(DEPCA_DATA));
      outw(CSR3,DEPCA_ADDR);
      printk("CSR3: 0x%4.4x\n",inw(DEPCA_DATA));
    }

    /*
    ** Enable DEPCA board interrupts
    */
    nicsr = ((nicsr & ~IM & ~LED)|SHE|IEN);
    outw(nicsr, DEPCA_NICSR);
    outw(CSR0,DEPCA_ADDR);

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

    InitRestartDepca(dev);                /* ignore the return status */

    if (depca_debug > 1){
      printk("CSR0: 0x%4.4x\n",inw(DEPCA_DATA));
      printk("nicsr: 0x%4.4x\n",inw(DEPCA_NICSR));
    }

    return 0;			          /* Always succeed */
}

/* Initialize the lance Rx and Tx descriptor rings. */
static void
depca_init_ring(struct device *dev)
{
    struct depca_private *lp = (struct depca_private *)dev->priv;
    unsigned long i;

    lp->init_block.mode = DTX | DRX;	     /* Disable Rx and Tx. */
    lp->cur_rx = lp->cur_tx = 0;
    lp->dirty_rx = lp->dirty_tx = 0;

    /* Initialize the base addresses and length of each buffer in the ring */
    for (i = 0; i < lp->ringSize; i++) {
	lp->rx_ring[i].base = (lp->dma_buffs + i*PKT_BUF_SZ) | R_OWN;
	lp->rx_ring[i].buf_length = -PKT_BUF_SZ;
	lp->tx_ring[i].base = (lp->dma_buffs + (i+lp->ringSize) * PKT_BUF_SZ) &
	                                           (unsigned long)(0x00ffffff);
    }

    /* Set up the initialization block */
    for (i = 0; i < ETH_ALEN; i++) {
      lp->init_block.phys_addr[i] = dev->dev_addr[i];
    }
    for (i = 0; i < 4; i++) {
      lp->init_block.filter[i] = 0x0000;
    }
    lp->init_block.rx_ring = (unsigned long)lp->rx_ring | lp->rlen;
    lp->init_block.tx_ring = (unsigned long)lp->tx_ring | lp->rlen;

    lp->init_block.mode = 0x0000;            /* Enable the Tx and Rx */ 
}

/* 
** Writes a socket buffer to TX descriptor ring and starts transmission 
*/
static int
depca_start_xmit(struct sk_buff *skb, struct device *dev)
{
    struct depca_private *lp = (struct depca_private *)dev->priv;
    int ioaddr = dev->base_addr;
    int status = 0;

    /* Transmitter timeout, serious problems. */
    if (dev->tbusy) {
      int tickssofar = jiffies - dev->trans_start;
      if (tickssofar < 5) {
	status = -1;
      } else {
	STOP_DEPCA;
	printk("%s: transmit timed out, status %4.4x, resetting.\n",
	       dev->name, inw(DEPCA_DATA));
	
	depca_init_ring(dev);
	LoadCSRs(dev);
	InitRestartDepca(dev);
	dev->tbusy=0;
	dev->trans_start = jiffies;
      }
      return status;
    }

    if (skb == NULL) {
	dev_tint(dev);
	return 0;
    }

    /* Fill in the ethernet header. */
    if (!skb->arp  &&  dev->rebuild_header(skb->data, dev)) {
	skb->dev = dev;
	arp_queue (skb);
	return 0;
    }
    skb->arp=1;

    if (skb->len <= 0) {
      return 0;
    }

    if (depca_debug > 3) {
	outw(CSR0, DEPCA_ADDR);
	printk("%s: depca_start_xmit() called, csr0 %4.4x.\n", dev->name,
	       inw(DEPCA_DATA));
    }

    /* Block a timer-based transmit from overlapping.  This could better be
       done with atomic_swap(1, dev->tbusy), but set_bit() works as well. */
    if (set_bit(0, (void*)&dev->tbusy) != 0)
	printk("%s: Transmitter access conflict.\n", dev->name);

    /*
    ** The TX buffer, skb, has to be copied into the local network RAM
    ** for the LANCE to access it. The skb may be at > 16MB for large 
    ** (memory) systems.
    */
    {				/* Fill in a Tx ring entry */
      unsigned char *buf;
      int entry = lp->cur_tx++;
      int len;
      long skbL = skb->len;
      char *p = (char *) skb->data;

      entry &= lp->rmask;  		    /* Ring around buffer number. */
      buf = (unsigned char *)(lp->tx_ring[entry].base & 0x00ffffff);

      /* Wait for a full ring to free up */
      while (lp->tx_ring[entry].base < 0);

      /* 
      ** Caution: the write order is important here... don't set up the
      ** ownership rights until all the other information is in place.
      */
      len = ((skbL > PKT_SZ) ? PKT_SZ : skbL); /* skb too long */
      if (len < ETH_ZLEN) len = ETH_ZLEN;      /* len too short */
      skbL -= len;
      lp->tx_ring[entry].length = -len;

      /* Clears various error flags */
      lp->tx_ring[entry].misc = 0x0000;

      /* copy the data from the socket buffer to the net memory */
      memcpy((unsigned char *)(buf), skb->data, len);

      /* Hand over buffer ownership to the LANCE */
      if (skbL <= 0) lp->tx_ring[entry].base |= (T_ENP);
      lp->tx_ring[entry].base |= (T_OWN|T_STP);

      /* Trigger an immediate send demand. */
      outw(CSR0, DEPCA_ADDR);
      outw(INEA | TDMD, DEPCA_DATA);

      dev->trans_start = jiffies;

      for (p += len; skbL > 0; p += len) {

	/* Get new buffer pointer */
	entry = lp->cur_tx++;
	entry &= lp->rmask;  		    /* Ring around buffer number. */
	buf = (unsigned char *)(lp->tx_ring[entry].base & 0x00ffffff);

	/* Wait for a full ring to free up */
	while (lp->tx_ring[entry].base < 0);
	dev->tbusy=0;

	/* Copy ethernet header to the new buffer */
	memcpy((unsigned char *)buf, skb->data, PKT_HDR_LEN);

	/* Determine length of data buffer */
	len = ((skbL > DAT_SZ) ? DAT_SZ : skbL); /* skbL too long */
	if (len < ETH_ZLEN) len = ETH_ZLEN;      /* len too short */
	skbL -= len;
	lp->tx_ring[entry].length = -len;

	/* Clears various error flags */
	lp->tx_ring[entry].misc = 0x0000;

	/* copy the data from the socket buffer to the net memory */
	memcpy((unsigned char *)(buf + PKT_HDR_LEN), (unsigned char *)p, len);

	/* Hand over buffer ownership to the LANCE */
	if (skbL <= 0) lp->tx_ring[entry].base |= T_ENP;
	lp->tx_ring[entry].base |= T_OWN;
      }

      if (depca_debug > 4) {
	unsigned char *pkt =
	  (unsigned char *)(lp->tx_ring[entry].base & 0x00ffffff);

	printk("%s: tx ring[%d], %#lx, sk_buf %#lx len %d.\n",
	       dev->name, entry, (unsigned long) &lp->tx_ring[entry],
	       lp->tx_ring[entry].base, -lp->tx_ring[entry].length);
	printk("%s:  Tx %2.2x %2.2x %2.2x ... %2.2x  %2.2x %2.2x %2.2x...%2.2x len %2.2x %2.2x  %2.2x %2.2x.\n",
	       dev->name, pkt[0], pkt[1], pkt[2], pkt[5], pkt[6],
	       pkt[7], pkt[8], pkt[11], pkt[12], pkt[13],
	       pkt[14], pkt[15]);
      }
      
      /* Check if the TX ring is full or not - 'tbusy' cleared if not full. */
      if (lp->tx_ring[(entry+1) & lp->rmask].base >= 0) {
	dev->tbusy=0;
      }

      if (skb->free) {
	kfree_skb (skb, FREE_WRITE);
      }
    }

    return 0;
}

/*
** The DEPCA interrupt handler. 
*/
static void
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:
 */