depca.c

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

    Written 1994, 1995 by David C. Davies.


                      Copyright 1994 David C. Davies
                                   and 
                         United States Government
         (as represented by the Director, National Security Agency).  

               Copyright 1995  Digital Equipment Corporation.


    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 and EtherWORKS ethernet cards:

        DEPCA       (the original)
        DE100
        DE101
        DE200 Turbo
        DE201 Turbo
        DE202 Turbo (TP BNC)
        DE210
        DE422       (EISA)

    The  driver has been tested on DE100, DE200 and DE202 cards  in  a
    relatively busy network. The DE422 has been tested a little.

    This  driver will NOT work   for the DE203,  DE204  and DE205 series  of
    cards,  since they have  a  new custom ASIC in   place of the AMD  LANCE
    chip.  See the 'ewrk3.c'   driver in the  Linux  source tree for running
    those cards.

    I have benchmarked the driver with a  DE100 at 595kB/s to (542kB/s from)
    a DECstation 5000/200.

    The author may be reached at davies@maniac.ultranet.com

    =========================================================================

    The  driver was originally based  on   the 'lance.c' driver from  Donald
    Becker   which  is included with  the  standard  driver distribution for
    linux.  V0.4  is  a complete  re-write  with only  the kernel  interface
    remaining from the original code.

    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 V0.1 of this
    driver.

    The original DEPCA  card requires that the  ethernet ROM address counter
    be enabled to count and has an 8 bit NICSR.  The ROM counter enabling is
    only  done when a  0x08 is read as the  first address octet (to minimise
    the chances  of writing over some  other hardware's  I/O register).  The
    NICSR accesses   have been changed  to  byte accesses  for all the cards
    supported by this driver, since there is only one  useful bit in the MSB
    (remote boot timeout) and it  is not used.  Also, there  is a maximum of
    only 48kB network  RAM for this  card.  My thanks  to Torbjorn Lindh for
    help debugging all this (and holding my feet to  the fire until I got it
    right).

    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 [16kB/48kB for the original DEPCA]).

    At the most only 2 DEPCA cards can  be supported on  the ISA bus because
    there is only provision  for two I/O base addresses  on each card (0x300
    and 0x200). The I/O address is detected by searching for a byte sequence
    in the Ethernet station address PROM at the expected I/O address for the
    Ethernet  PROM.   The shared memory  base   address  is 'autoprobed'  by
    looking  for the self  test PROM  and detecting the  card name.   When a
    second  DEPCA is  detected,  information  is   placed in the   base_addr
    variable of the  next device structure (which  is created if necessary),
    thus  enabling ethif_probe  initialization  for the device.  More than 2
    EISA cards can  be  supported, but  care will  be  needed assigning  the
    shared memory to ensure that each slot has the  correct IRQ, I/O address
    and shared memory address assigned.

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

    NOTE: If you are using two  ISA 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 cards   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. DEPCA and 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 ability to load this driver as a loadable module has been added. To
    utilise this ability, you have to do <8 things:

    0) have a copy of the loadable modules code installed on your system.
    1) copy depca.c from the  /linux/drivers/net directory to your favourite
    temporary directory.
    2) if you wish, edit the  source code near  line 1530 to reflect the I/O
    address and IRQ you're using (see also 5).
    3) compile  depca.c, but include -DMODULE in  the command line to ensure
    that the correct bits are compiled (see end of source code).
    4) if you are wanting to add a new  card, goto 5. Otherwise, recompile a
    kernel with the depca configuration turned off and reboot.
    5) insmod depca.o [irq=7] [io=0x200] [mem=0xd0000] [adapter_name=DE100]
       [Alan Cox: Changed the code to allow command line irq/io assignments]
       [Dave Davies: Changed the code to allow command line mem/name
                                                                assignments]
    6) run the net startup bits for your eth?? interface manually 
    (usually /etc/rc.inet[12] at boot time). 
    7) enjoy!

    Note that autoprobing is not allowed in loadable modules - the system is
    already up and running and you're messing with interrupts.

    To unload a module, turn off the associated interface 
    'ifconfig eth?? down' then 'rmmod depca'.

    To assign a base memory address for the shared memory  when running as a
    loadable module, see 5 above.  To include the adapter  name (if you have
    no PROM  but know the card name)  also see 5  above. Note that this last
    option  will not work  with kernel  built-in  depca's. 

    The shared memory assignment for a loadable module  makes sense to avoid
    the 'memory autoprobe' picking the wrong shared memory  (for the case of
    2 depca's in a PC).

    ************************************************************************
    Support for MCA EtherWORKS cards added 11-3-98.
    Verified to work with up to 2 DE212 cards in a system (although not
      fully stress-tested).  

    Currently known bugs/limitations:

    Note:  with the MCA stuff as a module, it trusts the MCA configuration,
           not the command line for IRQ and memory address.  You can
           specify them if you want, but it will throw your values out.
           You still have to pass the IO address it was configured as
           though.

    ************************************************************************
    TO DO:
    ------


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

    Version   Date        Description
  
      0.1     25-jan-94   Initial writing.
      0.2     27-jan-94   Added LANCE TX hardware 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.
      0.33    25-feb-94   Fix DEPCA ethernet ROM counter enable.
                          Add jabber packet fix from murf@perftech.com
                          and becker@super.org
      0.34     7-mar-94   Fix DEPCA max network memory RAM & NICSR access.
      0.35     8-mar-94   Added DE201 recognition. Tidied up.
      0.351   30-apr-94   Added EISA support. Added DE422 recognition.
      0.36    16-may-94   DE422 fix released.
      0.37    22-jul-94   Added MODULE support
      0.38    15-aug-94   Added DBR ROM switch in depca_close(). 
                          Multi DEPCA bug fix.
      0.38axp 15-sep-94   Special version for Alpha AXP Linux V1.0.
      0.381   12-dec-94   Added DE101 recognition, fix multicast bug.
      0.382    9-feb-95   Fix recognition bug reported by <bkm@star.rl.ac.uk>.
      0.383   22-feb-95   Fix for conflict with VESA SCSI reported by
                          <stromain@alf.dec.com>
      0.384   17-mar-95   Fix a ring full bug reported by <bkm@star.rl.ac.uk>
      0.385    3-apr-95   Fix a recognition bug reported by 
                                                <ryan.niemi@lastfrontier.com>
      0.386   21-apr-95   Fix the last fix...sorry, must be galloping senility
      0.40    25-May-95   Rewrite for portability & updated.
                          ALPHA support from <jestabro@amt.tay1.dec.com>
      0.41    26-Jun-95   Added verify_area() calls in depca_ioctl() from
                          suggestion by <heiko@colossus.escape.de>
      0.42    27-Dec-95   Add 'mem' shared memory assignment for loadable 
                          modules.
                          Add 'adapter_name' for loadable modules when no PROM.
                          Both above from a suggestion by 
                          <pchen@woodruffs121.residence.gatech.edu>.
                          Add new multicasting code.
      0.421   22-Apr-96   Fix alloc_device() bug <jari@markkus2.fimr.fi>
      0.422   29-Apr-96   Fix depca_hw_init() bug <jari@markkus2.fimr.fi>
      0.423    7-Jun-96   Fix module load bug <kmg@barco.be>
      0.43    16-Aug-96   Update alloc_device() to conform to de4x5.c
      0.44     1-Sep-97   Fix *_probe() to test check_region() first - bug
                           reported by <mmogilvi@elbert.uccs.edu>
      0.45     3-Nov-98   Added support for MCA EtherWORKS (DE210/DE212) cards
                           by <tymm@computer.org> 
      0.451    5-Nov-98   Fixed mca stuff cuz I'm a dummy. <tymm@computer.org>
      0.5     14-Nov-98   Re-spin for 2.1.x kernels.
      0.51    27-Jun-99   Correct received packet length for CRC from
                           report by <worm@dkik.dk>

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

static const char *version = "depca.c:v0.51 1999/6/27 davies@maniac.ultranet.com\n";

#include <linux/config.h>
#include <linux/module.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 <linux/delay.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <asm/bitops.h>
#include <asm/io.h>
#include <asm/dma.h>

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

#include <linux/time.h>
#include <linux/types.h>
#include <linux/unistd.h>
#include <linux/ctype.h>

#ifdef CONFIG_MCA
#include <linux/mca.h>
#endif

#include "depca.h"

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

#define DEPCA_NDA 0xffe0        /* No Device Address */

/*
** Ethernet PROM defines
*/
#define PROBE_LENGTH    32
#define ETH_PROM_SIG    0xAA5500FFUL

/*
** Set the number of Tx and Rx buffers. Ensure that the memory requested
** here is <= to the amount of shared memory set up by the board switches.
** The number of descriptors MUST BE A POWER OF 2.
**
** total_memory = NUM_RX_DESC*(8+RX_BUFF_SZ) + NUM_TX_DESC*(8+TX_BUFF_SZ)
*/
#define NUM_RX_DESC     8       /* Number of RX descriptors */
#define NUM_TX_DESC     8       /* Number of TX descriptors */
#define RX_BUFF_SZ      1536    /* Buffer size for each Rx buffer */
#define TX_BUFF_SZ      1536    /* Buffer size for each Tx buffer */

#define CRC_POLYNOMIAL_BE 0x04c11db7UL  /* Ethernet CRC, big endian */
#define CRC_POLYNOMIAL_LE 0xedb88320UL  /* Ethernet CRC, little endian */

/*
** EISA bus defines
*/
#define DEPCA_EISA_IO_PORTS 0x0c00      /* I/O port base address, slot 0 */
#define MAX_EISA_SLOTS 16
#define EISA_SLOT_INC 0x1000

/*
** ISA Bus defines
*/
#define DEPCA_RAM_BASE_ADDRESSES {0xc0000,0xd0000,0xe0000,0x00000}
#define DEPCA_IO_PORTS {0x300, 0x200, 0}
#define DEPCA_TOTAL_SIZE 0x10
static short mem_chkd = 0;

/*
** Adapter ID for the MCA EtherWORKS DE210/212 adapter
*/
#define DE212_ID 0x6def

/*
** Name <-> Adapter mapping
*/
#define DEPCA_SIGNATURE {"DEPCA",\
                         "DE100","DE101",\
                         "DE200","DE201","DE202",\
                         "DE210","DE212",\
                         "DE422",\
                         ""}
static enum {
        DEPCA, de100, de101, de200, de201, de202, de210, de212, de422, unknown
} adapter;

/*
** Miscellaneous info...
*/
#define DEPCA_STRLEN 16
#define MAX_NUM_DEPCAS 2

/*
** Memory Alignment. Each descriptor is 4 longwords long. To force a
** particular alignment on the TX descriptor, adjust DESC_SKIP_LEN and
** DESC_ALIGN. ALIGN aligns the start address of the private memory area
** and hence the RX descriptor ring's first entry. 
*/
#define ALIGN4      ((u_long)4 - 1)     /* 1 longword align */
#define ALIGN8      ((u_long)8 - 1)     /* 2 longword (quadword) align */
#define ALIGN         ALIGN8    /* Keep the LANCE happy... */

/*
** The DEPCA Rx and Tx ring descriptors. 
*/
struct depca_rx_desc {
        volatile s32 base;
        s16 buf_length;         /* This length is negative 2's complement! */
        s16 msg_length;         /* This length is "normal". */
};

struct depca_tx_desc {
        volatile s32 base;
        s16 length;             /* This length is negative 2's complement! */
        s16 misc;               /* Errors and TDR info */
};

#define LA_MASK 0x0000ffff      /* LANCE address mask for mapping network RAM
                                   to LANCE memory address space */

/*
** The Lance initialization block, described in databook, in common memory.
*/
struct depca_init {
        u16 mode;               /* Mode register */
        u8 phys_addr[ETH_ALEN]; /* Physical ethernet address */
        u8 mcast_table[8];      /* Multicast Hash Table. */
        u32 rx_ring;            /* Rx ring base pointer & ring length */
        u32 tx_ring;            /* Tx ring base pointer & ring length */
};

#define DEPCA_PKT_STAT_SZ 16
#define DEPCA_PKT_BIN_SZ  128   /* Should be >=100 unless you
                                   increase DEPCA_PKT_STAT_SZ */
struct depca_private {
        char devname[DEPCA_STRLEN];     /* Device Product String                  */
        char adapter_name[DEPCA_STRLEN];        /* /proc/ioports string                  */
        char adapter;           /* Adapter type                           */
        char mca_slot;          /* MCA slot, if MCA else -1               */
        struct depca_rx_desc *rx_ring;  /* Pointer to start of RX descriptor ring */
        struct depca_tx_desc *tx_ring;  /* Pointer to start of TX descriptor ring */
        struct depca_init init_block;   /* Shadow Initialization block            */
        char *rx_memcpy[NUM_RX_DESC];   /* CPU virt address of sh'd memory buffs  */
        char *tx_memcpy[NUM_TX_DESC];   /* CPU virt address of sh'd memory buffs  */
        u_long bus_offset;      /* (E)ISA bus address offset vs LANCE     */
        u_long sh_mem;          /* Physical start addr of shared mem area */
        u_long dma_buffs;       /* LANCE Rx and Tx buffers start address. */
        int rx_new, tx_new;     /* The next free ring entry               */
        int rx_old, tx_old;     /* The ring entries to be free()ed.       */
        struct net_device_stats stats;
        struct {                /* Private stats counters                 */
                u32 bins[DEPCA_PKT_STAT_SZ];
                u32 unicast;
                u32 multicast;
                u32 broadcast;
                u32 excessive_collisions;
                u32 tx_underruns;
                u32 excessive_underruns;
        } pktStats;
        int txRingMask;         /* TX ring mask                           */
        int rxRingMask;         /* RX ring mask                           */
        s32 rx_rlen;            /* log2(rxRingMask+1) for the descriptors */
        s32 tx_rlen;            /* log2(txRingMask+1) for the descriptors */
};

/*
** The transmit ring full condition is described by the tx_old and tx_new
** pointers by:
**    tx_old            = tx_new    Empty ring
**    tx_old            = tx_new+1  Full ring
**    tx_old+txRingMask = tx_new    Full ring  (wrapped condition)
*/
#define TX_BUFFS_AVAIL ((lp->tx_old<=lp->tx_new)?\
                         lp->tx_old+lp->txRingMask-lp->tx_new:\
                         lp->tx_old               -lp->tx_new-1)

/*
** 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 irq, void *dev_id, struct pt_regs *regs);
static int depca_close(struct device *dev);
static int depca_ioctl(struct device *dev, struct ifreq *rq, int cmd);
static struct net_device_stats *depca_get_stats(struct device *dev);
static void set_multicast_list(struct device *dev);

/*
** Private functions
*/
static int depca_hw_init(struct device *dev, u_long ioaddr, int mca_slot);
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 void DepcaSignature(char *name, u_long paddr);
static int DevicePresent(u_long ioaddr);
static int get_hw_addr(struct device *dev);
static int EISA_signature(char *name, s32 eisa_id);
static void SetMulticastFilter(struct device *dev);
static void isa_probe(struct device *dev, u_long iobase);
static void eisa_probe(struct device *dev, u_long iobase);
#ifdef CONFIG_MCA
static void mca_probe(struct device *dev, u_long iobase);
#endif
static struct device *alloc_device(struct device *dev, u_long iobase);
static int depca_dev_index(char *s);
static struct device *insert_device(struct device *dev, u_long iobase, int (*init) (struct device *));
static int load_packet(struct device *dev, struct sk_buff *skb);
static void depca_dbg_open(struct device *dev);

#ifdef MODULE
int init_module(void);
void cleanup_module(void);
static int autoprobed = 1, loading_module = 1;
# else
static u_char de1xx_irq[] __initdata = { 2, 3, 4, 5, 7, 9, 0 };
static u_char de2xx_irq[] __initdata = { 5, 9, 10, 11, 15, 0 };
static u_char de422_irq[] __initdata = { 5, 9, 10, 11, 0 };
static u_char *depca_irq;
static int autoprobed = 0, loading_module = 0;
#endif                          /* MODULE */

static char name[DEPCA_STRLEN];
static int num_depcas = 0, num_eth = 0;
static int mem = 0;             /* For loadable module assignment
                                   use insmod mem=0x????? .... */
static char *adapter_name = '\0';       /* If no PROM when loadable module
                                           use insmod adapter_name=DE??? ...
                                         */
/*
** Miscellaneous defines...
*/
#define STOP_DEPCA \
    outw(CSR0, DEPCA_ADDR);\
    outw(STOP, DEPCA_DATA)



__initfunc(int depca_probe(struct device *dev))
{
        int tmp = num_depcas, status = -ENODEV;
        u_long iobase = dev->base_addr;

        if ((iobase == 0) && loading_module) {
                printk("Autoprobing is not supported when loading a module based driver.\n");
                status = -EIO;
        } else {
#ifdef CONFIG_MCA
                mca_probe(dev, iobase);
#endif
                isa_probe(dev, iobase);
                eisa_probe(dev, iobase);

                if ((tmp == num_depcas) && (iobase != 0) && loading_module) {
                        printk("%s: depca_probe() cannot find device at 0x%04lx.\n", dev->name, iobase);
                }

                /*
                   ** Walk the device list to check that at least one device
                   ** initialised OK
                 */
                for (; (dev->priv == NULL) && (dev->next != NULL); dev = dev->next);

                if (dev->priv)
                        status = 0;
                if (iobase == 0)
                        autoprobed = 1;
        }

        return status;
}

__initfunc(static int depca_hw_init(struct device *dev, u_long ioaddr, int mca_slot))
{
        struct depca_private *lp;
        int i, j, offset, netRAM, mem_len, status = 0;
        s16 nicsr;
        u_long mem_start = 0, mem_base[] = DEPCA_RAM_BASE_ADDRESSES;

        STOP_DEPCA;

        nicsr = inb(DEPCA_NICSR);
        nicsr = ((nicsr & ~SHE & ~RBE & ~IEN) | IM);
        outb(nicsr, DEPCA_NICSR);

        if (inw(DEPCA_DATA) == STOP) {
                do {
                        strcpy(name, (adapter_name ? adapter_name : ""));
                        mem_start = (mem ? mem & 0xf0000 : mem_base[mem_chkd++]);
                        DepcaSignature(name, mem_start);
                } while (!mem && mem_base[mem_chkd] && (adapter == unknown));

                if ((adapter != unknown) && mem_start) {        /* found a DEPCA device */
                        dev->base_addr = ioaddr;

                        if (mca_slot != -1) {
                                printk("%s: %s at 0x%04lx (MCA slot %d)", dev->name, name, ioaddr, mca_slot);
                        } else if ((ioaddr & 0x0fff) == DEPCA_EISA_IO_PORTS) {  /* EISA slot address */
                                printk("%s: %s at 0x%04lx (EISA slot %d)", dev->name, name, ioaddr, (int) ((ioaddr >> 12) & 0x0f));
                        } else {        /* ISA port address */
                                printk("%s: %s at 0x%04lx", dev->name, name, ioaddr);
                        }

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

                        if (status == 0) {
                                /* Set up the maximum amount of network RAM(kB) */
                                netRAM = ((adapter != DEPCA) ? 64 : 48);
                                if ((nicsr & _128KB) && (adapter == de422))
                                        netRAM = 128;
                                offset = 0x0000;

                                /* Shared Memory Base Address */
                                if (nicsr & BUF) {
                                        offset = 0x8000;        /* 32kbyte RAM offset */
                                        nicsr &= ~BS;   /* DEPCA RAM in top 32k */
                                        netRAM -= 32;
                                }
                                mem_start += offset;    /* (E)ISA start address */
                                if ((mem_len = (NUM_RX_DESC * (sizeof(struct depca_rx_desc) + RX_BUFF_SZ) + NUM_TX_DESC * (sizeof(struct depca_tx_desc) + TX_BUFF_SZ) + sizeof(struct depca_init))) <= (netRAM << 10)) {
                                        printk(",\n      has %dkB RAM at 0x%.5lx", netRAM, mem_start);

                                        /* Enable the shadow RAM. */
                                        if (adapter != DEPCA) {
                                                nicsr |= SHE;
                                                outb(nicsr, DEPCA_NICSR);
                                        }

                                        /* Define the device private memory */
                                        dev->priv = (void *) kmalloc(sizeof(struct depca_private), GFP_KERNEL);
                                        if (dev->priv == NULL)
                                                return -ENOMEM;
                                        lp = (struct depca_private *) dev->priv;
                                        memset((char *) dev->priv, 0, sizeof(struct depca_private));
                                        lp->adapter = adapter;
                                        lp->mca_slot = mca_slot;
                                        sprintf(lp->adapter_name, "%s (%s)", name, dev->name);
                                        request_region(ioaddr, DEPCA_TOTAL_SIZE, lp->adapter_name);

                                        /* Initialisation Block */
                                        lp->sh_mem = mem_start;
                                        mem_start += sizeof(struct depca_init);

                                        /* Tx & Rx descriptors (aligned to a quadword boundary) */
                                        mem_start = (mem_start + ALIGN) & ~ALIGN;
                                        lp->rx_ring = (struct depca_rx_desc *) mem_start;

                                        mem_start += (sizeof(struct depca_rx_desc) * NUM_RX_DESC);
                                        lp->tx_ring = (struct depca_tx_desc *) mem_start;

                                        mem_start += (sizeof(struct depca_tx_desc) * NUM_TX_DESC);
                                        lp->bus_offset = mem_start & 0x00ff0000;
                                        mem_start &= LA_MASK;   /* LANCE re-mapped start address */

                                        lp->dma_buffs = mem_start;

                                        /* Finish initialising the ring information. */
                                        lp->rxRingMask = NUM_RX_DESC - 1;
                                        lp->txRingMask = NUM_TX_DESC - 1;

                                        /* Calculate Tx/Rx RLEN size for the descriptors. */
                                        for (i = 0, j = lp->rxRingMask; j > 0; i++) {
                                                j >>= 1;
                                        }
                                        lp->rx_rlen = (s32) (i << 29);
                                        for (i = 0, j = lp->txRingMask; j > 0; i++) {
                                                j >>= 1;
                                        }
                                        lp->tx_rlen = (s32) (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);
                                        outb(nicsr, DEPCA_NICSR);

                                        /* 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) {
#ifndef MODULE
                                                unsigned char irqnum;
                                                autoirq_setup(0);

                                                /* Assign the correct irq list */
                                                switch (lp->adapter) {
                                                case DEPCA:
                                                case de100:
                                                case de101:
                                                        depca_irq = de1xx_irq;
                                                        break;
                                                case de200:
                                                case de201:
                                                case de202:
                                                case de210:
                                                case de212:
                                                        depca_irq = de2xx_irq;
                                                        break;
                                                case de422:
                                                        depca_irq = de422_irq;
                                                        break;
                                                }

                                                /* Trigger an initialization just for the interrupt. */
                                                outw(INEA | INIT, DEPCA_DATA);

                                                irqnum = autoirq_report(1);
                                                if (!irqnum) {
                                                        printk(" and failed to detect IRQ line.\n");
                                                        status = -ENXIO;
                                                } else {
                                                        for (dev->irq = 0, i = 0; (depca_irq[i]) && (!dev->irq); i++) {
                                                                if (irqnum == depca_irq[i]) {
                                                                        dev->irq = irqnum;
                                                                        printk(" and uses IRQ%d.\n", dev->irq);
                                                                }
                                                        }

                                                        if (!dev->irq) {
                                                                printk(" but incorrect IRQ line detected.\n");
                                                                status = -ENXIO;
                                                        }
                                                }
#endif                          /* MODULE */
                                        } else {
                                                printk(" and assigned IRQ%d.\n", dev->irq);
                                        }
                                        if (status)
                                                release_region(ioaddr, DEPCA_TOTAL_SIZE);
                                } else {
                                        printk(",\n      requests %dkB RAM: only %dkB is available!\n", (mem_len >> 10), netRAM);
                                        status = -ENXIO;
                                }
                        } else {
                                printk("      which has an Ethernet PROM CRC error.\n");
                                status = -ENXIO;
                        }
                } else {
                        status = -ENXIO;
                }
                if (!status) {
                        if (depca_debug > 1) {
                                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;
                        dev->set_multicast_list = &set_multicast_list;
                        dev->do_ioctl = &depca_ioctl;

                        dev->mem_start = 0;

                        /* Fill in the generic field of the device structure. */
                        ether_setup(dev);
                } else {        /* Incorrectly initialised hardware */
                        if (dev->priv) {
                                kfree_s(dev->priv, sizeof(struct depca_private));
                                dev->priv = NULL;
                        }
                }
        } else {
                status = -ENXIO;
        }

        return status;
}


static int depca_open(struct device *dev)
{
        struct depca_private *lp = (struct depca_private *) dev->priv;
        u_long ioaddr = dev->base_addr;
        s16 nicsr;
        int status = 0;

        STOP_DEPCA;
        nicsr = inb(DEPCA_NICSR);

        /* Make sure the shadow RAM is enabled */
        if (adapter != DEPCA) {
                nicsr |= SHE;
                outb(nicsr, DEPCA_NICSR);
        }

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

        depca_dbg_open(dev);

        if (request_irq(dev->irq, &depca_interrupt, 0, lp->adapter_name, dev)) {
                printk("depca_open(): Requested IRQ%d is busy\n", dev->irq);
                status = -EAGAIN;
        } else {

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

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

                status = InitRestartDepca(dev);

                if (depca_debug > 1) {
                        printk("CSR0: 0x%4.4x\n", inw(DEPCA_DATA));
                        printk("nicsr: 0x%02x\n", inb(DEPCA_NICSR));
                }
        }

        MOD_INC_USE_COUNT;

        return status;
}

/* 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;
        u_int i;
        u_long p;

        /* Lock out other processes whilst setting up the hardware */
        test_and_set_bit(0, (void *) &dev->tbusy);

        lp->rx_new = lp->tx_new = 0;
        lp->rx_old = lp->tx_old = 0;

        /* Initialize the base addresses and length of each buffer in the ring */
        for (i = 0; i <= lp->rxRingMask; i++) {
                writel((p = lp->dma_buffs + i * RX_BUFF_SZ) | R_OWN, &lp->rx_ring[i].base);
                writew(-RX_BUFF_SZ, &lp->rx_ring[i].buf_length);
                lp->rx_memcpy[i] = (char *) (p + lp->bus_offset);
        }
        for (i = 0; i <= lp->txRingMask; i++) {
                writel((p = lp->dma_buffs + (i + lp->txRingMask + 1) * TX_BUFF_SZ) & 0x00ffffff, &lp->tx_ring[i].base);
                lp->tx_memcpy[i] = (char *) (p + lp->bus_offset);
        }

        /* Set up the initialization block */
        lp->init_block.rx_ring = ((u32) ((u_long) lp->rx_ring) & LA_MASK) | lp->rx_rlen;
        lp->init_block.tx_ring = ((u32) ((u_long) lp->tx_ring) & LA_MASK) | lp->tx_rlen;

        SetMulticastFilter(dev);

        for (i = 0; i < ETH_ALEN; i++) {
                lp->init_block.phys_addr[i] = dev->dev_addr[i];
        }

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

        return;
}

/* 
** 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;
        u_long ioaddr = dev->base_addr;
        int status = 0;

        /* Transmitter timeout, serious problems. */
        if (dev->tbusy) {
                int tickssofar = jiffies - dev->trans_start;
                if (tickssofar < 1 * HZ) {
                        status = -1;
                } else {
                        printk("%s: transmit timed out, status %04x, resetting.\n", dev->name, inw(DEPCA_DATA));

                        STOP_DEPCA;
                        depca_init_ring(dev);
                        LoadCSRs(dev);
                        dev->interrupt = UNMASK_INTERRUPTS;
                        dev->start = 1;
                        dev->tbusy = 0;
                        dev->trans_start = jiffies;
                        InitRestartDepca(dev);
                }
                return status;
        } else if (skb->len > 0) {
                if(skb->len < ETH_ZLEN)
                {
                        skb = skb_padto(skb, ETH_ZLEN);
                        if(skb == NULL)
                                return 0;
                }

                /* Enforce 1 process per h/w access */
                if (test_and_set_bit(0, (void *) &dev->tbusy) != 0) {
                        printk("%s: Transmitter access conflict.\n", dev->name);
                        status = -1;
                } else {
                        if (TX_BUFFS_AVAIL) {   /* Fill in a Tx ring entry */
                                status = load_packet(dev, skb);

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

                                        dev->trans_start = jiffies;
                                        dev_kfree_skb(skb);
                                }
                                if (TX_BUFFS_AVAIL) {
                                        dev->tbusy = 0;
                                }
                        } else {
                                status = -1;
                        }
                }
        }

        return status;
}

/*
** The DEPCA interrupt handler. 
*/
static void depca_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
        struct device *dev = dev_id;
        struct depca_private *lp;
        s16 csr0, nicsr;
        u_long ioaddr;

        if (dev == NULL) {
                printk("depca_interrupt(): irq %d for unknown device.\n", irq);
        } 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 = inb(DEPCA_NICSR);
                nicsr |= (IM | LED);
                outb(nicsr, DEPCA_NICSR);

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

                /* Acknowledge all of the current interrupt sources ASAP. */
                outw(csr0 & INTE, DEPCA_DATA);

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

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

                if ((TX_BUFFS_AVAIL >= 0) && dev->tbusy) {      /* any resources available? */
                        dev->tbusy = 0; /* clear TX busy flag */
                        mark_bh(NET_BH);
                }

                /* Unmask the DEPCA board interrupts and turn off the LED */
                nicsr = (nicsr & ~IM & ~LED);
                outb(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 i, entry;
        s32 status;

        for (entry = lp->rx_new; !(readl(&lp->rx_ring[entry].base) & R_OWN); entry = lp->rx_new) {
                status = readl(&lp->rx_ring[entry].base) >> 16;
                if (status & R_STP) {   /* Remember start of frame */
                        lp->rx_old = entry;
                }
                if (status & R_ENP) {   /* Valid frame status */
                        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 {
                                short len, pkt_len = readw(&lp->rx_ring[entry].msg_length) - 4;
                                struct sk_buff *skb;

                                skb = dev_alloc_skb(pkt_len + 2);
                                if (skb != NULL) {
                                        unsigned char *buf;
                                        skb_reserve(skb, 2);    /* 16 byte align the IP header */
                                        buf = skb_put(skb, pkt_len);
                                        skb->dev = dev;
                                        if (entry < lp->rx_old) {       /* Wrapped buffer */
                                                len = (lp->rxRingMask - lp->rx_old + 1) * RX_BUFF_SZ;
                                                memcpy_fromio(buf, lp->rx_memcpy[lp->rx_old], len);
                                                memcpy_fromio(buf + len, lp->rx_memcpy[0], pkt_len - len);
                                        } else {        /* Linear buffer */
                                                memcpy_fromio(buf, lp->rx_memcpy[lp->rx_old], pkt_len);
                                        }

                                        /* 
                                           ** Notify the upper protocol layers that there is another 
                                           ** packet to handle
                                         */
                                        skb->protocol = eth_type_trans(skb, dev);
                                        netif_rx(skb);

                                        /*
                                           ** Update stats
                                         */
                                        lp->stats.rx_packets++;
                                        for (i = 1; i < DEPCA_PKT_STAT_SZ - 1; i++) {
                                                if (pkt_len < (i * DEPCA_PKT_BIN_SZ)) {
                                                        lp->pktStats.bins[i]++;
                                                        i = DEPCA_PKT_STAT_SZ;
                                                }
                                        }
                                        if (buf[0] & 0x01) {    /* Multicast/Broadcast */
                                                if ((*(s16 *) & buf[0] == -1) && (*(s16 *) & buf[2] == -1) && (*(s16 *) & buf[4] == -1)) {
                                                        lp->pktStats.broadcast++;
                                                } else {
                                                        lp->pktStats.multicast++;
                                                }
                                        } else if ((*(s16 *) & buf[0] == *(s16 *) & dev->dev_addr[0]) && (*(s16 *) & buf[2] == *(s16 *) & dev->dev_addr[2]) && (*(s16 *) & buf[4] == *(s16 *) & dev->dev_addr[4])) {
                                                lp->pktStats.unicast++;
                                        }

                                        lp->pktStats.bins[0]++; /* Duplicates stats.rx_packets */
                                        if (lp->pktStats.bins[0] == 0) {        /* Reset counters */
                                                memset((char *) &lp->pktStats, 0, sizeof(lp->pktStats));
                                        }
                                } else {
                                        printk("%s: Memory squeeze, deferring packet.\n", dev->name);
                                        lp->stats.rx_dropped++; /* Really, deferred. */
                                        break;
                                }
                        }
                        /* Change buffer ownership for this last frame, back to the adapter */
                        for (; lp->rx_old != entry; lp->rx_old = (++lp->rx_old) & lp->rxRingMask) {
                                writel(readl(&lp->rx_ring[lp->rx_old].base) | R_OWN, &lp->rx_ring[lp->rx_old].base);
                        }
                        writel(readl(&lp->rx_ring[entry].base) | R_OWN, &lp->rx_ring[entry].base);
                }

                /*
                   ** Update entry information
                 */
                lp->rx_new = (++lp->rx_new) & lp->rxRingMask;
        }

        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 entry;
        s32 status;
        u_long ioaddr = dev->base_addr;

        for (entry = lp->tx_old; entry != lp->tx_new; entry = lp->tx_old) {
                status = readl(&lp->tx_ring[entry].base) >> 16;

                if (status < 0) {       /* Packet not yet sent! */
                        break;
                } else if (status & T_ERR) {    /* An error occurred. */
                        status = readl(&lp->tx_ring[entry].misc);
                        lp->stats.tx_errors++;
                        if (status & TMD3_RTRY)
                                lp->stats.tx_aborted_errors++;
                        if (status & TMD3_LCAR)
                                lp->stats.tx_carrier_errors++;
                        if (status & TMD3_LCOL)
                                lp->stats.tx_window_errors++;
                        if (status & TMD3_UFLO)
                                lp->stats.tx_fifo_errors++;
                        if (status & (TMD3_BUFF | TMD3_UFLO)) {
                                /* Trigger an immediate send demand. */
                                outw(CSR0, DEPCA_ADDR);
                                outw(INEA | TDMD, DEPCA_DATA);
                        }
                } else if (status & (T_MORE | T_ONE)) {
                        lp->stats.collisions++;
                } else {
                        lp->stats.tx_packets++;
                }

                /* Update all the pointers */
                lp->tx_old = (++lp->tx_old) & lp->txRingMask;
        }

        return 0;
}

static int depca_close(struct device *dev)
{
        struct depca_private *lp = (struct depca_private *) dev->priv;
        s16 nicsr;
        u_long 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);

        /*
           ** Give back the ROM in case the user wants to go to DOS
         */
        if (lp->adapter != DEPCA) {
                nicsr = inb(DEPCA_NICSR);
                nicsr &= ~SHE;
                outb(nicsr, DEPCA_NICSR);
        }

        /*
           ** Free the associated irq
         */
        free_irq(dev->irq, dev);

        MOD_DEC_USE_COUNT;

        return 0;
}

static void LoadCSRs(struct device *dev)
{