/*
 *      Digi RightSwitch SE-X loadable device driver for Linux
 *
 *      The RightSwitch is a 4 (EISA) or 6 (PCI) port etherswitch and
 *      a NIC on an internal board.
 *
 *      Author: Rick Richardson, rick@remotepoint.com
 *      Derived from the SVR4.2 (UnixWare) driver for the same card.
 *
 *      Copyright 1995-1996 Digi International Inc.
 *
 *      This software may be used and distributed according to the terms
 *      of the GNU General Public License, incorporated herein by reference.
 *
 *      For information on purchasing a RightSwitch SE-4 or SE-6
 *      board, please contact Digi's sales department at 1-612-912-3444
 *      or 1-800-DIGIBRD.  Outside the U.S., please check our Web page
 *      at http://www.dgii.com for sales offices worldwide.
 *
 *      OPERATION:
 *      When compiled as a loadable module, this driver can operate
 *      the board as either a 4/6 port switch with a 5th or 7th port
 *      that is a conventional NIC interface as far as the host is
 *      concerned, OR as 4/6 independent NICs.  To select multi-NIC
 *      mode, add "nicmode=1" on the insmod load line for the driver.
 *
 *      This driver uses the "dev" common ethernet device structure
 *      and a private "priv" (dev->priv) structure that contains
 *      mostly DGRS-specific information and statistics.  To keep
 *      the code for both the switch mode and the multi-NIC mode
 *      as similar as possible, I have introduced the concept of
 *      "dev0"/"priv0" and "devN"/"privN"  pointer pairs in subroutines
 *      where needed.  The first pair of pointers points to the
 *      "dev" and "priv" structures of the zeroth (0th) device
 *      interface associated with a board.  The second pair of
 *      pointers points to the current (Nth) device interface
 *      for the board: the one for which we are processing data.
 *
 *      In switch mode, the pairs of pointers are always the same,
 *      that is, dev0 == devN and priv0 == privN.  This is just
 *      like previous releases of this driver which did not support
 *      NIC mode.
 *
 *      In multi-NIC mode, the pairs of pointers may be different.
 *      We use the devN and privN pointers to reference just the
 *      name, port number, and statistics for the current interface.
 *      We use the dev0 and priv0 pointers to access the variables
 *      that control access to the board, such as board address
 *      and simulated 82596 variables.  This is because there is
 *      only one "fake" 82596 that serves as the interface to
 *      the board.  We do not want to try to keep the variables
 *      associated with this 82596 in sync across all devices.
 *
 *      This scheme works well.  As you will see, except for
 *      initialization, there is very little difference between
 *      the two modes as far as this driver is concerned.  On the
 *      receive side in NIC mode, the interrupt *always* comes in on
 *      the 0th interface (dev0/priv0).  We then figure out which
 *      real 82596 port it came in on from looking at the "chan"
 *      member that the board firmware adds at the end of each
 *      RBD (a.k.a. TBD). We get the channel number like this:
 *              int chan = ((I596_RBD *) S2H(cbp->xmit.tbdp))->chan;
 *
 *      On the transmit side in multi-NIC mode, we specify the
 *      output 82596 port by setting the new "dstchan" structure
 *      member that is at the end of the RFD, like this:
 *              priv0->rfdp->dstchan = privN->chan;
 *
 *      TODO:
 *      - Multi-NIC mode is not yet supported when the driver is linked
 *        into the kernel.
 *      - Better handling of multicast addresses.
 *
 *      Fixes:
 *      Arnaldo Carvalho de Melo <acme@conectiva.com.br> - 11/01/2001
 *      - fix dgrs_found_device wrt checking kmalloc return and
 *      rollbacking the partial steps of the whole process when
 *      one of the devices can't be allocated. Fix SET_MODULE_OWNER
 *      on the loop to use devN instead of repeated calls to dev.
 *
 *      davej <davej@suse.de> - 9/2/2001
 *      - Enable PCI device before reading ioaddr/irq
 *
 */

#include <linux/module.h>
#include <linux/eisa.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>

#include <asm/bitops.h>
#include <asm/io.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>

static char version[] __initdata =
        "$Id: dgrs.c,v 1.13 2000/06/06 04:07:00 rick Exp $";

/*
 *      DGRS include files
 */
typedef unsigned char uchar;
typedef unsigned int bool;
#define vol volatile

#include "dgrs.h"
#include "dgrs_es4h.h"
#include "dgrs_plx9060.h"
#include "dgrs_i82596.h"
#include "dgrs_ether.h"
#include "dgrs_asstruct.h"
#include "dgrs_bcomm.h"

static struct pci_device_id dgrs_pci_tbl[] = {
        { SE6_PCI_VENDOR_ID, SE6_PCI_DEVICE_ID, PCI_ANY_ID, PCI_ANY_ID, },
        { }                     /* Terminating entry */
};
MODULE_DEVICE_TABLE(pci, dgrs_pci_tbl);
MODULE_LICENSE("GPL");


/*
 *      Firmware.  Compiled separately for local compilation,
 *      but #included for Linux distribution.
 */
#ifndef NOFW
        #include "dgrs_firmware.c"
#else
        extern int      dgrs_firmnum;
        extern char     dgrs_firmver[];
        extern char     dgrs_firmdate[];
        extern uchar    dgrs_code[];
        extern int      dgrs_ncode;
#endif

/*
 *      Linux out*() is backwards from all other operating systems
 */
#define OUTB(ADDR, VAL) outb(VAL, ADDR)
#define OUTW(ADDR, VAL) outw(VAL, ADDR)
#define OUTL(ADDR, VAL) outl(VAL, ADDR)

/*
 *      Macros to convert switch to host and host to switch addresses
 *      (assumes a local variable priv points to board dependent struct)
 */
#define S2H(A)  ( ((unsigned long)(A)&0x00ffffff) + priv0->vmem )
#define S2HN(A) ( ((unsigned long)(A)&0x00ffffff) + privN->vmem )
#define H2S(A)  ( ((char *) (A) - priv0->vmem) + 0xA3000000 )

/*
 *      Convert a switch address to a "safe" address for use with the
 *      PLX 9060 DMA registers and the associated HW kludge that allows
 *      for host access of the DMA registers.
 */
#define S2DMA(A)        ( (unsigned long)(A) & 0x00ffffff)

/*
 *      "Space.c" variables, now settable from module interface
 *      Use the name below, minus the "dgrs_" prefix.  See init_module().
 */
static int      dgrs_debug = 1;
static int      dgrs_dma = 1;
static int      dgrs_spantree = -1;
static int      dgrs_hashexpire = -1;
static uchar    dgrs_ipaddr[4] = { 0xff, 0xff, 0xff, 0xff};
static uchar    dgrs_iptrap[4] = { 0xff, 0xff, 0xff, 0xff};
static __u32    dgrs_ipxnet = -1;
static int      dgrs_nicmode;

/*
 *      Chain of device structures
 */
static struct net_device *dgrs_root_dev;

/*
 *      Private per-board data structure (dev->priv)
 */
typedef struct
{
        /*
         *      Stuff for generic ethercard I/F
         */
        struct net_device               *next_dev;
        struct net_device_stats stats;

        /*
         *      DGRS specific data
         */
        char            *vmem;

        struct bios_comm *bcomm;        /* Firmware BIOS comm structure */
        PORT            *port;          /* Ptr to PORT[0] struct in VM */
        I596_SCB        *scbp;          /* Ptr to SCB struct in VM */
        I596_RFD        *rfdp;          /* Current RFD list */
        I596_RBD        *rbdp;          /* Current RBD list */

        volatile int    intrcnt;        /* Count of interrupts */

        /*
         *      SE-4 (EISA) board variables
         */
        uchar           is_reg;         /* EISA: Value for ES4H_IS reg */

        /*
         *      SE-6 (PCI) board variables
         *
         *      The PLX "expansion rom" space is used for DMA register
         *      access from the host on the SE-6.  These are the physical
         *      and virtual addresses of that space.
         */
        ulong           plxreg;         /* Phys address of PLX chip */
        char            *vplxreg;       /* Virtual address of PLX chip */
        ulong           plxdma;         /* Phys addr of PLX "expansion rom" */
        ulong volatile  *vplxdma;       /* Virtual addr of "expansion rom" */
        int             use_dma;        /* Flag: use DMA */
        DMACHAIN        *dmadesc_s;     /* area for DMA chains (SW addr.) */
        DMACHAIN        *dmadesc_h;     /* area for DMA chains (Host Virtual) */

        /*
         *      Multi-NIC mode variables
         *
         *      All entries of the devtbl[] array are valid for the 0th
         *      device (i.e. eth0, but not eth1...eth5).  devtbl[0] is
         *      valid for all devices (i.e. eth0, eth1, ..., eth5).
         */
        int             nports;         /* Number of physical ports (4 or 6) */
        int             chan;           /* Channel # (1-6) for this device */
        struct net_device       *devtbl[6];     /* Ptrs to N device structs */

} DGRS_PRIV;


/*
 *      reset or un-reset the IDT processor
 */
static void
proc_reset(struct net_device *dev0, int reset)
{
        DGRS_PRIV       *priv0 = (DGRS_PRIV *) dev0->priv;

        if (priv0->plxreg)
        {
                ulong           val;
                val = inl(dev0->base_addr + PLX_MISC_CSR);
                if (reset)
                        val |= SE6_RESET;
                else
                        val &= ~SE6_RESET;
                OUTL(dev0->base_addr + PLX_MISC_CSR, val);
        }
        else
        {
                OUTB(dev0->base_addr + ES4H_PC, reset ? ES4H_PC_RESET : 0);
        }
}

/*
 *      See if the board supports bus master DMA
 */
static int
check_board_dma(struct net_device *dev0)
{
        DGRS_PRIV       *priv0 = (DGRS_PRIV *) dev0->priv;
        ulong   x;

        /*
         *      If Space.c says not to use DMA, or if it's not a PLX based
         *      PCI board, or if the expansion ROM space is not PCI
         *      configured, then return false.
         */
        if (!dgrs_dma || !priv0->plxreg || !priv0->plxdma)
                return (0);

        /*
         *      Set the local address remap register of the "expansion rom"
         *      area to 0x80000000 so that we can use it to access the DMA
         *      registers from the host side.
         */
        OUTL(dev0->base_addr + PLX_ROM_BASE_ADDR, 0x80000000);

        /*
         * Set the PCI region descriptor to:
         *      Space 0:
         *              disable read-prefetch
         *              enable READY
         *              enable BURST
         *              0 internal wait states
         *      Expansion ROM: (used for host DMA register access)
         *              disable read-prefetch
         *              enable READY
         *              disable BURST
         *              0 internal wait states
         */
        OUTL(dev0->base_addr + PLX_BUS_REGION, 0x49430343);

        /*
         *      Now map the DMA registers into our virtual space
         */
        priv0->vplxdma = (ulong *) ioremap (priv0->plxdma, 256);
        if (!priv0->vplxdma)
        {
                printk("%s: can't *remap() the DMA regs\n", dev0->name);
                return (0);
        }

        /*
         *      Now test to see if we can access the DMA registers
         *      If we write -1 and get back 1FFF, then we accessed the
         *      DMA register.  Otherwise, we probably have an old board
         *      and wrote into regular RAM.
         */
        priv0->vplxdma[PLX_DMA0_MODE/4] = 0xFFFFFFFF;
        x = priv0->vplxdma[PLX_DMA0_MODE/4];
        if (x != 0x00001FFF)
                return (0);

        return (1);
}

/*
 *      Initiate DMA using PLX part on PCI board.  Spin the
 *      processor until completed.  All addresses are physical!
 *
 *      If pciaddr is NULL, then it's a chaining DMA, and lcladdr is
 *      the address of the first DMA descriptor in the chain.
 *
 *      If pciaddr is not NULL, then it's a single DMA.
 *
 *      In either case, "lcladdr" must have been fixed up to make
 *      sure the MSB isn't set using the S2DMA macro before passing
 *      the address to this routine.
 */
static int
do_plx_dma(
        struct net_device *dev,
        ulong pciaddr,
        ulong lcladdr,
        int len,
        int to_host
)
{
        int             i;
        ulong           csr = 0;
        DGRS_PRIV       *priv = (DGRS_PRIV *) dev->priv;

        if (pciaddr)
        {
                /*
                 *      Do a single, non-chain DMA
                 */
                priv->vplxdma[PLX_DMA0_PCI_ADDR/4] = pciaddr;
                priv->vplxdma[PLX_DMA0_LCL_ADDR/4] = lcladdr;
                priv->vplxdma[PLX_DMA0_SIZE/4] = len;
                priv->vplxdma[PLX_DMA0_DESCRIPTOR/4] = to_host
                                        ? PLX_DMA_DESC_TO_HOST
                                        : PLX_DMA_DESC_TO_BOARD;
                priv->vplxdma[PLX_DMA0_MODE/4] =
                                          PLX_DMA_MODE_WIDTH32
                                        | PLX_DMA_MODE_WAITSTATES(0)
                                        | PLX_DMA_MODE_READY
                                        | PLX_DMA_MODE_NOBTERM
                                        | PLX_DMA_MODE_BURST
                                        | PLX_DMA_MODE_NOCHAIN;
        }
        else
        {
                /*
                 *      Do a chaining DMA
                 */
                priv->vplxdma[PLX_DMA0_MODE/4] =
                                          PLX_DMA_MODE_WIDTH32
                                        | PLX_DMA_MODE_WAITSTATES(0)
                                        | PLX_DMA_MODE_READY
                                        | PLX_DMA_MODE_NOBTERM
                                        | PLX_DMA_MODE_BURST
                                        | PLX_DMA_MODE_CHAIN;
                priv->vplxdma[PLX_DMA0_DESCRIPTOR/4] = lcladdr;
        }

        priv->vplxdma[PLX_DMA_CSR/4] =
                                PLX_DMA_CSR_0_ENABLE | PLX_DMA_CSR_0_START;

        /*
         *      Wait for DMA to complete
         */
        for (i = 0; i < 1000000; ++i)
        {
                /*
                 *      Spin the host CPU for 1 usec, so we don't thrash
                 *      the PCI bus while the PLX 9060 is doing DMA.
                 */
                udelay(1);

                csr = (volatile unsigned long) priv->vplxdma[PLX_DMA_CSR/4];

                if (csr & PLX_DMA_CSR_0_DONE)
                        break;
        }

        if ( ! (csr & PLX_DMA_CSR_0_DONE) )
        {
                printk("%s: DMA done never occurred. DMA disabled.\n",
                        dev->name);
                priv->use_dma = 0;
                return 1;
        }
        return 0;
}

/*
 *      dgrs_rcv_frame()
 *
 *      Process a received frame.  This is called from the interrupt
 *      routine, and works for both switch mode and multi-NIC mode.
 *
 *      Note that when in multi-NIC mode, we want to always access the
 *      hardware using the dev and priv structures of the first port,
 *      so that we are using only one set of variables to maintain
 *      the board interface status, but we want to use the Nth port
 *      dev and priv structures to maintain statistics and to pass
 *      the packet up.
 *
 *      Only the first device structure is attached to the interrupt.
 *      We use the special "chan" variable at the end of the first RBD
 *      to select the Nth device in multi-NIC mode.
 *
 *      We currently do chained DMA on a per-packet basis when the
 *      packet is "long", and we spin the CPU a short time polling
 *      for DMA completion.  This avoids a second interrupt overhead,
 *      and gives the best performance for light traffic to the host.
 *
 *      However, a better scheme that could be implemented would be
 *      to see how many packets are outstanding for the host, and if
 *      the number is "large", create a long chain to DMA several
 *      packets into the host in one go.  In this case, we would set
 *      up some state variables to let the host CPU continue doing
 *      other things until a DMA completion interrupt comes along.
 */
void
dgrs_rcv_frame(
        struct net_device       *dev0,
        DGRS_PRIV       *priv0,
        I596_CB         *cbp
)
{
        int             len;
        I596_TBD        *tbdp;
        struct sk_buff  *skb;
        uchar           *putp;
        uchar           *p;
        struct net_device       *devN;
        DGRS_PRIV       *privN;

        /*
         *      Determine Nth priv and dev structure pointers
         */
        if (dgrs_nicmode)
        {       /* Multi-NIC mode */
                int chan = ((I596_RBD *) S2H(cbp->xmit.tbdp))->chan;

                devN = priv0->devtbl[chan-1];
                /*
                 * If devN is null, we got an interrupt before the I/F
                 * has been initialized.  Pitch the packet.
                 */
                if (devN == NULL)
                        goto out;
                privN = (DGRS_PRIV *) devN->priv;
        }
        else
        {       /* Switch mode */
                devN = dev0;
                privN = priv0;
        }

        if (0) printk("%s: rcv len=%ld\n", devN->name, cbp->xmit.count);

        /*
         *      Allocate a message block big enough to hold the whole frame
         */
        len = cbp->xmit.count;
        if ((skb = dev_alloc_skb(len+5)) == NULL)
        {
                printk("%s: dev_alloc_skb failed for rcv buffer\n", devN->name);
                ++privN->stats.rx_dropped;
                /* discarding the frame */
                goto out;
        }
        skb->dev = devN;
        skb_reserve(skb, 2);    /* Align IP header */

again:
        putp = p = skb_put(skb, len);

        /*
         *      There are three modes here for doing the packet copy.
         *      If we have DMA, and the packet is "long", we use the
         *      chaining mode of DMA.  If it's shorter, we use single
         *      DMA's.  Otherwise, we use memcpy().
         */
        if (priv0->use_dma && priv0->dmadesc_h && len > 64)
        {
                /*
                 *      If we can use DMA and it's a long frame, copy it using
                 *      DMA chaining.
                 */
                DMACHAIN        *ddp_h; /* Host virtual DMA desc. pointer */
                DMACHAIN        *ddp_s; /* Switch physical DMA desc. pointer */
                uchar           *phys_p;

                /*
                 *      Get the physical address of the STREAMS buffer.
                 *      NOTE: allocb() guarantees that the whole buffer
                 *      is in a single page if the length < 4096.
                 */
                phys_p = (uchar *) virt_to_phys(putp);

                ddp_h = priv0->dmadesc_h;
                ddp_s = priv0->dmadesc_s;
                tbdp = (I596_TBD *) S2H(cbp->xmit.tbdp);
                for (;;)
                {
                        int     count;
                        int     amt;

                        count = tbdp->count;
                        amt = count & 0x3fff;
                        if (amt == 0)
                                break; /* For safety */
                        if ( (p-putp) >= len)
                        {
                                printk("%s: cbp = %lx\n", devN->name, (long) H2S(cbp));
                                proc_reset(dev0, 1);    /* Freeze IDT */
                                break; /* For Safety */
                        }

                        ddp_h->pciaddr = (ulong) phys_p;
                        ddp_h->lcladdr = S2DMA(tbdp->buf);
                        ddp_h->len = amt;

                        phys_p += amt;
                        p += amt;

                        if (count & I596_TBD_EOF)
                        {
                                ddp_h->next = PLX_DMA_DESC_TO_HOST
                                                | PLX_DMA_DESC_EOC;
                                ++ddp_h;
                                break;
                        }
                        else
                        {
                                ++ddp_s;
                                ddp_h->next = PLX_DMA_DESC_TO_HOST
                                                | (ulong) ddp_s;
                                tbdp = (I596_TBD *) S2H(tbdp->next);
                                ++ddp_h;
                        }
                }
                if (ddp_h - priv0->dmadesc_h)
                {
                        int     rc;

                        rc = do_plx_dma(dev0,
                                0, (ulong) priv0->dmadesc_s, len, 0);
                        if (rc)
                        {
                                printk("%s: Chained DMA failure\n", devN->name);
                                goto again;
                        }
                }
        }
        else if (priv0->use_dma)
        {
                /*
                 *      If we can use DMA and it's a shorter frame, copy it
                 *      using single DMA transfers.
                 */
                uchar           *phys_p;

                /*
                 *      Get the physical address of the STREAMS buffer.
                 *      NOTE: allocb() guarantees that the whole buffer
                 *      is in a single page if the length < 4096.
                 */
                phys_p = (uchar *) virt_to_phys(putp);

                tbdp = (I596_TBD *) S2H(cbp->xmit.tbdp);
                for (;;)
                {
                        int     count;
                        int     amt;
                        int     rc;

                        count = tbdp->count;
                        amt = count & 0x3fff;
                        if (amt == 0)
                                break; /* For safety */
                        if ( (p-putp) >= len)
                        {
                                printk("%s: cbp = %lx\n", devN->name, (long) H2S(cbp));
                                proc_reset(dev0, 1);    /* Freeze IDT */
                                break; /* For Safety */
                        }
                        rc = do_plx_dma(dev0, (ulong) phys_p,
                                                S2DMA(tbdp->buf), amt, 1);
                        if (rc)
                        {
                                memcpy(p, S2H(tbdp->buf), amt);
                                printk("%s: Single DMA failed\n", devN->name);
                        }
                        phys_p += amt;
                        p += amt;
                        if (count & I596_TBD_EOF)
                                break;
                        tbdp = (I596_TBD *) S2H(tbdp->next);
                }
        }
        else
        {
                /*
                 *      Otherwise, copy it piece by piece using memcpy()
                 */
                tbdp = (I596_TBD *) S2H(cbp->xmit.tbdp);
                for (;;)
                {
                        int     count;
                        int     amt;

                        count = tbdp->count;
                        amt = count & 0x3fff;
                        if (amt == 0)
                                break; /* For safety */
                        if ( (p-putp) >= len)
                        {
                                printk("%s: cbp = %lx\n", devN->name, (long) H2S(cbp));
                                proc_reset(dev0, 1);    /* Freeze IDT */
                                break; /* For Safety */
                        }
                        memcpy(p, S2H(tbdp->buf), amt);
                        p += amt;
                        if (count & I596_TBD_EOF)
                                break;
                        tbdp = (I596_TBD *) S2H(tbdp->next);
                }
        }

        /*
         *      Pass the frame to upper half
         */
        skb->protocol = eth_type_trans(skb, devN);
        netif_rx(skb);
        devN->last_rx = jiffies;
        ++privN->stats.rx_packets;
        privN->stats.rx_bytes += len;

out:
        cbp->xmit.status = I596_CB_STATUS_C | I596_CB_STATUS_OK;
}

/*
 *      Start transmission of a frame
 *
 *      The interface to the board is simple: we pretend that we are
 *      a fifth 82596 ethernet controller 'receiving' data, and copy the
 *      data into the same structures that a real 82596 would.  This way,
 *      the board firmware handles the host 'port' the same as any other.
 *
 *      NOTE: we do not use Bus master DMA for this routine.  Turns out
 *      that it is not needed.  Slave writes over the PCI bus are about
 *      as fast as DMA, due to the fact that the PLX part can do burst
 *      writes.  The same is not true for data being read from the board.
 *
 *      For multi-NIC mode, we tell the firmware the desired 82596
 *      output port by setting the special "dstchan" member at the
 *      end of the traditional 82596 RFD structure.
 */

static int dgrs_start_xmit(struct sk_buff *skb, struct net_device *devN)
{
        DGRS_PRIV       *privN = (DGRS_PRIV *) devN->priv;
        struct net_device       *dev0;
        DGRS_PRIV       *priv0;
        I596_RBD        *rbdp;
        int             count;
        int             i, len, amt;

        /*
         *      Determine 0th priv and dev structure pointers
         */
        if (dgrs_nicmode)
        {
                dev0 = privN->devtbl[0];
                priv0 = (DGRS_PRIV *) dev0->priv;
        }
        else
        {
                dev0 = devN;
                priv0 = privN;
        }

        if (dgrs_debug > 1)
                printk("%s: xmit len=%d\n", devN->name, (int) skb->len);

        devN->trans_start = jiffies;
        netif_start_queue(devN);

        if (priv0->rfdp->cmd & I596_RFD_EL)
        {       /* Out of RFD's */
                if (0) printk("%s: NO RFD's\n", devN->name);
                goto no_resources;
        }

        rbdp = priv0->rbdp;
        count = 0;
        priv0->rfdp->rbdp = (I596_RBD *) H2S(rbdp);

        i = 0; len = skb->len;
        for (;;)
        {
                if (rbdp->size & I596_RBD_EL)
                {       /* Out of RBD's */
                        if (0) printk("%s: NO RBD's\n", devN->name);
                        goto no_resources;
                }

                amt = min_t(unsigned int, len, rbdp->size - count);
                memcpy( (char *) S2H(rbdp->buf) + count, skb->data + i, amt);
                i += amt;
                count += amt;
                len -= amt;
                if (len == 0)
                {
                        if (skb->len < 60)
                                rbdp->count = 60 | I596_RBD_EOF;
                        else
                                rbdp->count = count | I596_RBD_EOF;
                        rbdp = (I596_RBD *) S2H(rbdp->next);
                        goto frame_done;
                }
                else if (count < 32)
                {
                        /* More data to come, but we used less than 32
                         * bytes of this RBD.  Keep filling this RBD.
                         */
                        {}      /* Yes, we do nothing here */
                }
                else
                {
                        rbdp->count = count;
                        rbdp = (I596_RBD *) S2H(rbdp->next);
                        count = 0;
                }
        }

frame_done:
        priv0->rbdp = rbdp;
        if (dgrs_nicmode)
                priv0->rfdp->dstchan = privN->chan;
        priv0->rfdp->status = I596_RFD_C | I596_RFD_OK;
        priv0->rfdp = (I596_RFD *) S2H(priv0->rfdp->next);

        ++privN->stats.tx_packets;

        dev_kfree_skb (skb);
        return (0);

no_resources:
        priv0->scbp->status |= I596_SCB_RNR;    /* simulate I82596 */
        return (-EAGAIN);
}

/*
 *      Open the interface
 */
static int
dgrs_open( struct net_device *dev )
{
        netif_start_queue(dev);
        return (0);
}

/*
 *      Close the interface
 */
static int dgrs_close( struct net_device *dev )
{
        netif_stop_queue(dev);
        return (0);
}

/*
 *      Get statistics
 */
static struct net_device_stats *dgrs_get_stats( struct net_device *dev )
{
        DGRS_PRIV       *priv = (DGRS_PRIV *) dev->priv;

        return (&priv->stats);
}

/*
 *      Set multicast list and/or promiscuous mode
 */

static void dgrs_set_multicast_list( struct net_device *dev)
{
        DGRS_PRIV       *priv = (DGRS_PRIV *) dev->priv;

        priv->port->is_promisc = (dev->flags & IFF_PROMISC) ? 1 : 0;
}

/*
 *      Unique ioctl's
 */
static int dgrs_ioctl(struct net_device *devN, struct ifreq *ifr, int cmd)
{
        DGRS_PRIV       *privN = (DGRS_PRIV *) devN->priv;
        DGRS_IOCTL      ioc;
        int             i;

        if (cmd != DGRSIOCTL)
                return -EINVAL;

        if(copy_from_user(&ioc, ifr->ifr_data, sizeof(DGRS_IOCTL)))
                return -EFAULT;

        switch (ioc.cmd)
        {
                case DGRS_GETMEM:
                        if (ioc.len != sizeof(ulong))
                                return -EINVAL;
                        if(copy_to_user(ioc.data, &devN->mem_start, ioc.len))
                                return -EFAULT;
                        return (0);
                case DGRS_SETFILTER:
                        if (!capable(CAP_NET_ADMIN))
                                return -EPERM;
                        if (ioc.port > privN->bcomm->bc_nports)
                                return -EINVAL;
                        if (ioc.filter >= NFILTERS)
                                return -EINVAL;
                        if (ioc.len > privN->bcomm->bc_filter_area_len)
                                return -EINVAL;

                        /* Wait for old command to finish */
                        for (i = 0; i < 1000; ++i)
                        {
                                if ( (volatile long) privN->bcomm->bc_filter_cmd <= 0 )
                                        break;
                                udelay(1);
                        }
                        if (i >= 1000)
                                return -EIO;

                        privN->bcomm->bc_filter_port = ioc.port;
                        privN->bcomm->bc_filter_num = ioc.filter;
                        privN->bcomm->bc_filter_len = ioc.len;
        
                        if (ioc.len)
                        {
                                if(copy_from_user(S2HN(privN->bcomm->bc_filter_area),
                                        ioc.data, ioc.len))
                                        return -EFAULT;
                                privN->bcomm->bc_filter_cmd = BC_FILTER_SET;
                        }
                        else
                                privN->bcomm->bc_filter_cmd = BC_FILTER_CLR;
                        return(0);
                default:
                        return -EOPNOTSUPP;
        }
}

/*
 *      Process interrupts
 *
 *      dev, priv will always refer to the 0th device in Multi-NIC mode.
 */

static irqreturn_t dgrs_intr(int irq, void *dev_id, struct pt_regs *regs)
{
        struct net_device       *dev0 = (struct net_device *) dev_id;
        DGRS_PRIV       *priv0 = (DGRS_PRIV *) dev0->priv;
        I596_CB         *cbp;
        int             cmd;
        int             i;

        ++priv0->intrcnt;
        if (1) ++priv0->bcomm->bc_cnt[4];
        if (0)
        {
                static int cnt = 100;
                if (--cnt > 0)
                printk("%s: interrupt: irq %d\n", dev0->name, irq);
        }

        /*
         *      Get 596 command
         */
        cmd = priv0->scbp->cmd;

        /*
         *      See if RU has been restarted
         */
        if ( (cmd & I596_SCB_RUC) == I596_SCB_RUC_START)
        {
                if (0) printk("%s: RUC start\n", dev0->name);
                priv0->rfdp = (I596_RFD *) S2H(priv0->scbp->rfdp);
                priv0->rbdp = (I596_RBD *) S2H(priv0->rfdp->rbdp);
                priv0->scbp->status &= ~(I596_SCB_RNR|I596_SCB_RUS);
                /*
                 * Tell upper half (halves)
                 */
                if (dgrs_nicmode)
                {
                        for (i = 0; i < priv0->nports; ++i)
                                netif_wake_queue (priv0->devtbl[i]);
                }
                else
                        netif_wake_queue (dev0);
                /* if (bd->flags & TX_QUEUED)
                        DL_sched(bd, bdd); */
        }

        /*
         *      See if any CU commands to process
         */
        if ( (cmd & I596_SCB_CUC) != I596_SCB_CUC_START)
        {
                priv0->scbp->cmd = 0;   /* Ignore all other commands */
                goto ack_intr;
        }
        priv0->scbp->status &= ~(I596_SCB_CNA|I596_SCB_CUS);

        /*
         *      Process a command
         */
        cbp = (I596_CB *) S2H(priv0->scbp->cbp);
        priv0->scbp->cmd = 0;   /* Safe to clear the command */
        for (;;)
        {
                switch (cbp->nop.cmd & I596_CB_CMD)
                {
                case I596_CB_CMD_XMIT:
                        dgrs_rcv_frame(dev0, priv0, cbp);
                        break;
                default:
                        cbp->nop.status = I596_CB_STATUS_C | I596_CB_STATUS_OK;
                        break;
                }
                if (cbp->nop.cmd & I596_CB_CMD_EL)
                        break;
                cbp = (I596_CB *) S2H(cbp->nop.next);
        }
        priv0->scbp->status |= I596_SCB_CNA;

        /*
         * Ack the interrupt
         */
ack_intr:
        if (priv0->plxreg)
                OUTL(dev0->base_addr + PLX_LCL2PCI_DOORBELL, 1);

        return IRQ_HANDLED;
}

/*
 *      Download the board firmware
 */
static int __init 
dgrs_download(struct net_device *dev0)
{
        DGRS_PRIV       *priv0 = (DGRS_PRIV *) dev0->priv;
        int             is;
        unsigned long   i;

        static int      iv2is[16] = {
                                0, 0, 0, ES4H_IS_INT3,
                                0, ES4H_IS_INT5, 0, ES4H_IS_INT7,
                                0, 0, ES4H_IS_INT10, ES4H_IS_INT11,
                                ES4H_IS_INT12, 0, 0, ES4H_IS_INT15 };

        /*
         * Map in the dual port memory
         */
        priv0->vmem = ioremap(dev0->mem_start, 2048*1024);
        if (!priv0->vmem)
        {

                printk("%s: cannot map in board memory\n", dev0->name);
                return -ENXIO;
        }

        /*
         *      Hold the processor and configure the board addresses
         */
        if (priv0->plxreg)
        {       /* PCI bus */
                proc_reset(dev0, 1);
        }
        else
        {       /* EISA bus */
                is = iv2is[dev0->irq & 0x0f];
                if (!is)
                {
                        printk("%s: Illegal IRQ %d\n", dev0->name, dev0->irq);
                        return -ENXIO;
                }
                OUTB(dev0->base_addr + ES4H_AS_31_24,
                        (uchar) (dev0->mem_start >> 24) );
                OUTB(dev0->base_addr + ES4H_AS_23_16,
                        (uchar) (dev0->mem_start >> 16) );
                priv0->is_reg = ES4H_IS_LINEAR | is |
                        ((uchar) (dev0->mem_start >> 8) & ES4H_IS_AS15);
                OUTB(dev0->base_addr + ES4H_IS, priv0->is_reg);
                OUTB(dev0->base_addr + ES4H_EC, ES4H_EC_ENABLE);
                OUTB(dev0->base_addr + ES4H_PC, ES4H_PC_RESET);
                OUTB(dev0->base_addr + ES4H_MW, ES4H_MW_ENABLE | 0x00);
        }

        /*
         *      See if we can do DMA on the SE-6
         */
        priv0->use_dma = check_board_dma(dev0);
        if (priv0->use_dma)
                printk("%s: Bus Master DMA is enabled.\n", dev0->name);

        /*
         * Load and verify the code at the desired address
         */
        memcpy(priv0->vmem, dgrs_code, dgrs_ncode);     /* Load code */
        if (memcmp(priv0->vmem, dgrs_code, dgrs_ncode))
        {
                iounmap(priv0->vmem);
                priv0->vmem = NULL;
                printk("%s: download compare failed\n", dev0->name);
                return -ENXIO;
        }

        /*
         * Configurables
         */
        priv0->bcomm = (struct bios_comm *) (priv0->vmem + 0x0100);
        priv0->bcomm->bc_nowait = 1;    /* Tell board to make printf not wait */
        priv0->bcomm->bc_squelch = 0;   /* Flag from Space.c */
        priv0->bcomm->bc_150ohm = 0;    /* Flag from Space.c */

        priv0->bcomm->bc_spew = 0;      /* Debug flag from Space.c */
        priv0->bcomm->bc_maxrfd = 0;    /* Debug flag from Space.c */
        priv0->bcomm->bc_maxrbd = 0;    /* Debug flag from Space.c */

        /*
         * Tell board we are operating in switch mode (1) or in
         * multi-NIC mode (2).
         */
        priv0->bcomm->bc_host = dgrs_nicmode ? BC_MULTINIC : BC_SWITCH;

        /*
         * Request memory space on board for DMA chains
         */
        if (priv0->use_dma)
                priv0->bcomm->bc_hostarea_len = (2048/64) * 16;

        /*
         * NVRAM configurables from Space.c
         */
        priv0->bcomm->bc_spantree = dgrs_spantree;
        priv0->bcomm->bc_hashexpire = dgrs_hashexpire;
        memcpy(priv0->bcomm->bc_ipaddr, dgrs_ipaddr, 4);
        memcpy(priv0->bcomm->bc_iptrap, dgrs_iptrap, 4);
        memcpy(priv0->bcomm->bc_ipxnet, &dgrs_ipxnet, 4);

        /*
         * Release processor, wait 8 seconds for board to initialize
         */
        proc_reset(dev0, 0);

        for (i = jiffies + 8 * HZ; time_after(i, jiffies); )
        {
                barrier();              /* Gcc 2.95 needs this */
                if (priv0->bcomm->bc_status >= BC_RUN)
                        break;
        }

        if (priv0->bcomm->bc_status < BC_RUN)
        {
                printk("%s: board not operating\n", dev0->name);
                return -ENXIO;
        }

        priv0->port = (PORT *) S2H(priv0->bcomm->bc_port);
        priv0->scbp = (I596_SCB *) S2H(priv0->port->scbp);
        priv0->rfdp = (I596_RFD *) S2H(priv0->scbp->rfdp);
        priv0->rbdp = (I596_RBD *) S2H(priv0->rfdp->rbdp);

        priv0->scbp->status = I596_SCB_CNA;     /* CU is idle */

        /*
         *      Get switch physical and host virtual pointers to DMA
         *      chaining area.  NOTE: the MSB of the switch physical
         *      address *must* be turned off.  Otherwise, the HW kludge
         *      that allows host access of the PLX DMA registers will
         *      erroneously select the PLX registers.
         */
        priv0->dmadesc_s = (DMACHAIN *) S2DMA(priv0->bcomm->bc_hostarea);
        if (priv0->dmadesc_s)
                priv0->dmadesc_h = (DMACHAIN *) S2H(priv0->dmadesc_s);
        else
                priv0->dmadesc_h = NULL;

        /*
         *      Enable board interrupts
         */
        if (priv0->plxreg)
        {       /* PCI bus */
                OUTL(dev0->base_addr + PLX_INT_CSR,
                        inl(dev0->base_addr + PLX_INT_CSR)
                        | PLX_PCI_DOORBELL_IE); /* Enable intr to host */
                OUTL(dev0->base_addr + PLX_LCL2PCI_DOORBELL, 1);
        }
        else
        {       /* EISA bus */
        }

        return (0);
}

/*
 *      Probe (init) a board
 */
int __init 
dgrs_probe1(struct net_device *dev)
{
        DGRS_PRIV       *priv = (DGRS_PRIV *) dev->priv;
        unsigned long   i;
        int             rc;

        printk("%s: Digi RightSwitch io=%lx mem=%lx irq=%d plx=%lx dma=%lx\n",
                dev->name, dev->base_addr, dev->mem_start, dev->irq,
                priv->plxreg, priv->plxdma);

        /*
         *      Download the firmware and light the processor
         */
        rc = dgrs_download(dev);
        if (rc)
                goto err_out;

        /*
         * Get ether address of board
         */
        printk("%s: Ethernet address", dev->name);
        memcpy(dev->dev_addr, priv->port->ethaddr, 6);
        for (i = 0; i < 6; ++i)
                printk("%c%2.2x", i ? ':' : ' ', dev->dev_addr[i]);
        printk("\n");

        if (dev->dev_addr[0] & 1)
        {
                printk("%s: Illegal Ethernet Address\n", dev->name);
                rc = -ENXIO;
                goto err_out;
        }

        /*
         *      ACK outstanding interrupts, hook the interrupt,
         *      and verify that we are getting interrupts from the board.
         */
        if (priv->plxreg)
                OUTL(dev->base_addr + PLX_LCL2PCI_DOORBELL, 1);
        
        rc = request_irq(dev->irq, &dgrs_intr, SA_SHIRQ, "RightSwitch", dev);
        if (rc)
                goto err_out;

        priv->intrcnt = 0;
        for (i = jiffies + 2*HZ + HZ/2; time_after(i, jiffies); )
        {
                barrier();              /* gcc 2.95 needs this */
                if (priv->intrcnt >= 2)
                        break;
        }
        if (priv->intrcnt < 2)
        {
                printk(KERN_ERR "%s: Not interrupting on IRQ %d (%d)\n",
                                dev->name, dev->irq, priv->intrcnt);
                rc = -ENXIO;
                goto err_free_irq;
        }

        /*
         *      Register the /proc/ioports information...
         */
        if (!request_region(dev->base_addr, 256, "RightSwitch")) {
                printk(KERN_ERR "%s: io 0x%3lX, which is busy.\n", dev->name,
                                dev->base_addr);
                rc = -EBUSY;
                goto err_free_irq;
        }
        
        /*
         *      Entry points...
         */
        dev->open = &dgrs_open;
        dev->stop = &dgrs_close;
        dev->get_stats = &dgrs_get_stats;
        dev->hard_start_xmit = &dgrs_start_xmit;
        dev->set_multicast_list = &dgrs_set_multicast_list;
        dev->do_ioctl = &dgrs_ioctl;

        return rc;

err_free_irq:
        free_irq(dev->irq, dev);
err_out:
        return rc;
}

int __init 
dgrs_initclone(struct net_device *dev)
{
        DGRS_PRIV       *priv = (DGRS_PRIV *) dev->priv;
        int             i;

        printk("%s: Digi RightSwitch port %d ",
                dev->name, priv->chan);
        for (i = 0; i < 6; ++i)
                printk("%c%2.2x", i ? ':' : ' ', dev->dev_addr[i]);
        printk("\n");

        return (0);
}

static int __init 
dgrs_found_device(
        int             io,
        ulong           mem,
        int             irq,
        ulong           plxreg,
        ulong           plxdma
)
{
        DGRS_PRIV       *priv;
        struct net_device *dev, *aux;
        int i, ret;

        dev = alloc_etherdev(sizeof(DGRS_PRIV));
        if (!dev)
                return -ENOMEM;

        priv = (DGRS_PRIV *)dev->priv;

        dev->base_addr = io;
        dev->mem_start = mem;
        dev->mem_end = mem + 2048 * 1024 - 1;
        dev->irq = irq;
        priv->plxreg = plxreg;
        priv->plxdma = plxdma;
        priv->vplxdma = NULL;

        priv->chan = 1;
        priv->devtbl[0] = dev;

        dev->init = dgrs_probe1;
        SET_MODULE_OWNER(dev);

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

        priv->next_dev = dgrs_root_dev;
        dgrs_root_dev = dev;

        if ( !dgrs_nicmode )
                return (0);     /* Switch mode, we are done */

        /*
         * Operating card as N separate NICs
         */

        priv->nports = priv->bcomm->bc_nports;

        for (i = 1; i < priv->nports; ++i)
        {
                struct net_device       *devN;
                DGRS_PRIV       *privN;
                        /* Allocate new dev and priv structures */
                devN = alloc_etherdev(sizeof(DGRS_PRIV));
                ret = -ENOMEM;
                if (!devN) 
                        goto fail;

                /* Make it an exact copy of dev[0]... */
                *devN = *dev;

                /* copy the priv structure of dev[0] */
                privN = (DGRS_PRIV *)devN->priv;
                *privN = *priv;

                        /* ... and zero out VM areas */
                privN->vmem = 0;
                privN->vplxdma = 0;
                        /* ... and zero out IRQ */
                devN->irq = 0;
                        /* ... and base MAC address off address of 1st port */
                devN->dev_addr[5] += i;
                        /* ... choose a new name */
                strncpy(devN->name, "eth%d", IFNAMSIZ);
                devN->init = dgrs_initclone;
                SET_MODULE_OWNER(devN);

                ret = -EIO;
                if (register_netdev(devN)) {
                        free_netdev(devN);
                        goto fail;
                }
                privN->chan = i+1;
                priv->devtbl[i] = devN;
                privN->next_dev = dgrs_root_dev;
                dgrs_root_dev = devN;
        }
        return 0;
fail:   aux = priv->next_dev;
        while (dgrs_root_dev != aux) {
                struct net_device *d = dgrs_root_dev;
                
                dgrs_root_dev = ((DGRS_PRIV *)d->priv)->next_dev;
                unregister_netdev(d);
                free_netdev(d);
        }
        return ret;
}

/*
 *      Scan for all boards
 */
static int is2iv[8] __initdata = { 0, 3, 5, 7, 10, 11, 12, 15 };

static int __init  dgrs_scan(void)
{
        int     cards_found = 0;
        uint    io;
        uint    mem;
        uint    irq;
        uint    plxreg;
        uint    plxdma;
        struct pci_dev *pdev = NULL;

        /*
         *      First, check for PCI boards
         */
        while ((pdev = pci_find_device(SE6_PCI_VENDOR_ID, SE6_PCI_DEVICE_ID, pdev)) != NULL)
        {
                /*
                 * Get and check the bus-master and latency values.
                 * Some PCI BIOSes fail to set the master-enable bit,
                 * and the latency timer must be set to the maximum
                 * value to avoid data corruption that occurs when the
                 * timer expires during a transfer.  Yes, it's a bug.
                 */
                if (pci_enable_device(pdev))
                        continue;
                pci_set_master(pdev);

                plxreg = pci_resource_start (pdev, 0);
                io = pci_resource_start (pdev, 1);
                mem = pci_resource_start (pdev, 2);
                pci_read_config_dword(pdev, 0x30, &plxdma);
                irq = pdev->irq;
                plxdma &= ~15;

                /*
                 * On some BIOSES, the PLX "expansion rom" (used for DMA)
                 * address comes up as "0".  This is probably because
                 * the BIOS doesn't see a valid 55 AA ROM signature at
                 * the "ROM" start and zeroes the address.  To get
                 * around this problem the SE-6 is configured to ask
                 * for 4 MB of space for the dual port memory.  We then
                 * must set its range back to 2 MB, and use the upper
                 * half for DMA register access
                 */
                OUTL(io + PLX_SPACE0_RANGE, 0xFFE00000L);
                if (plxdma == 0)
                        plxdma = mem + (2048L * 1024L);
                pci_write_config_dword(pdev, 0x30, plxdma + 1);
                pci_read_config_dword(pdev, 0x30, &plxdma);
                plxdma &= ~15;

                dgrs_found_device(io, mem, irq, plxreg, plxdma);

                cards_found++;
        }

        /*
         *      Second, check for EISA boards
         */
        if (EISA_bus)
        {
                for (io = 0x1000; io < 0x9000; io += 0x1000)
                {
                        if (inb(io+ES4H_MANUFmsb) != 0x10
                                || inb(io+ES4H_MANUFlsb) != 0x49
                                || inb(io+ES4H_PRODUCT) != ES4H_PRODUCT_CODE)
                                continue;

                        if ( ! (inb(io+ES4H_EC) & ES4H_EC_ENABLE) )
                                continue; /* Not EISA configured */

                        mem = (inb(io+ES4H_AS_31_24) << 24)
                                + (inb(io+ES4H_AS_23_16) << 16);

                        irq = is2iv[ inb(io+ES4H_IS) & ES4H_IS_INTMASK ];

                        dgrs_found_device(io, mem, irq, 0L, 0L);

                        ++cards_found;
                }
        }

        return cards_found;
}


/*
 *      Variables that can be overriden from module command line
 */
static int      debug = -1;
static int      dma = -1;
static int      hashexpire = -1;
static int      spantree = -1;
static int      ipaddr[4] = { -1 };
static int      iptrap[4] = { -1 };
static __u32    ipxnet = -1;
static int      nicmode = -1;

MODULE_PARM(debug, "i");
MODULE_PARM(dma, "i");
MODULE_PARM(hashexpire, "i");
MODULE_PARM(spantree, "i");
MODULE_PARM(ipaddr, "1-4i");
MODULE_PARM(iptrap, "1-4i");
MODULE_PARM(ipxnet, "i");
MODULE_PARM(nicmode, "i");
MODULE_PARM_DESC(debug, "Digi RightSwitch enable debugging (0-1)");
MODULE_PARM_DESC(dma, "Digi RightSwitch enable BM DMA (0-1)");
MODULE_PARM_DESC(nicmode, "Digi RightSwitch operating mode (1: switch, 2: multi-NIC)");

static int __init dgrs_init_module (void)
{
        int     cards_found;
        int     i;

        /*
         *      Command line variable overrides
         *              debug=NNN
         *              dma=0/1
         *              spantree=0/1
         *              hashexpire=NNN
         *              ipaddr=A,B,C,D
         *              iptrap=A,B,C,D
         *              ipxnet=NNN
         *              nicmode=NNN
         */
        if (debug >= 0)
                dgrs_debug = debug;
        if (dma >= 0)
                dgrs_dma = dma;
        if (nicmode >= 0)
                dgrs_nicmode = nicmode;
        if (hashexpire >= 0)
                dgrs_hashexpire = hashexpire;
        if (spantree >= 0)
                dgrs_spantree = spantree;
        if (ipaddr[0] != -1)
                for (i = 0; i < 4; ++i)
                        dgrs_ipaddr[i] = ipaddr[i];
        if (iptrap[0] != -1)
                for (i = 0; i < 4; ++i)
                        dgrs_iptrap[i] = iptrap[i];
        if (ipxnet != -1)
                dgrs_ipxnet = htonl( ipxnet );

        if (dgrs_debug)
        {
                printk(KERN_INFO "dgrs: SW=%s FW=Build %d %s\nFW Version=%s\n",
                       version, dgrs_firmnum, dgrs_firmdate, dgrs_firmver);
        }

        /*
         *      Find and configure all the cards
         */
        dgrs_root_dev = NULL;
        cards_found = dgrs_scan();

        return cards_found ? 0 : -ENODEV;
}

static void __exit dgrs_cleanup_module (void)
{
        while (dgrs_root_dev)
        {
                struct net_device       *next_dev;
                DGRS_PRIV       *priv;

                priv = (DGRS_PRIV *) dgrs_root_dev->priv;
                next_dev = priv->next_dev;
                unregister_netdev(dgrs_root_dev);

                proc_reset(priv->devtbl[0], 1);

                if (priv->vmem)
                        iounmap(priv->vmem);
                if (priv->vplxdma)
                        iounmap((uchar *) priv->vplxdma);

                release_region(dgrs_root_dev->base_addr, 256);

                if (dgrs_root_dev->irq)
                        free_irq(dgrs_root_dev->irq, dgrs_root_dev);

                free_netdev(dgrs_root_dev);
                dgrs_root_dev = next_dev;
        }
}

module_init(dgrs_init_module);
module_exit(dgrs_cleanup_module);