treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / net / appletalk / cops.c

/*      cops.c: LocalTalk driver for Linux.
 *
 *      Authors:
 *      - Jay Schulist <jschlst@samba.org>
 *
 *      With more than a little help from;
 *      - Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 *      Derived from:
 *      - skeleton.c: A network driver outline for linux.
 *        Written 1993-94 by Donald Becker.
 *      - ltpc.c: A driver for the LocalTalk PC card.
 *        Written by Bradford W. Johnson.
 *
 *      Copyright 1993 United States Government as represented by the
 *      Director, National Security Agency.
 *
 *      This software may be used and distributed according to the terms
 *      of the GNU General Public License, incorporated herein by reference.
 *
 *      Changes:
 *      19970608        Alan Cox        Allowed dual card type support
 *                                      Can set board type in insmod
 *                                      Hooks for cops_setup routine
 *                                      (not yet implemented).
 *      19971101        Jay Schulist    Fixes for multiple lt* devices.
 *      19980607        Steven Hirsch   Fixed the badly broken support
 *                                      for Tangent type cards. Only
 *                                      tested on Daystar LT200. Some
 *                                      cleanup of formatting and program
 *                                      logic.  Added emacs 'local-vars'
 *                                      setup for Jay's brace style.
 *      20000211        Alan Cox        Cleaned up for softnet
 */

static const char *version =
"cops.c:v0.04 6/7/98 Jay Schulist <jschlst@samba.org>\n";
/*
 *  Sources:
 *      COPS Localtalk SDK. This provides almost all of the information
 *      needed.
 */

/*
 * insmod/modprobe configurable stuff.
 *      - IO Port, choose one your card supports or 0 if you dare.
 *      - IRQ, also choose one your card supports or nothing and let
 *        the driver figure it out.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/if_ltalk.h>
#include <linux/delay.h>        /* For udelay() */
#include <linux/atalk.h>
#include <linux/spinlock.h>
#include <linux/bitops.h>
#include <linux/jiffies.h>

#include <asm/io.h>
#include <asm/dma.h>

#include "cops.h"               /* Our Stuff */
#include "cops_ltdrv.h"         /* Firmware code for Tangent type cards. */
#include "cops_ffdrv.h"         /* Firmware code for Dayna type cards. */

/*
 *      The name of the card. Is used for messages and in the requests for
 *      io regions, irqs and dma channels
 */

static const char *cardname = "cops";

#ifdef CONFIG_COPS_DAYNA
static int board_type = DAYNA;  /* Module exported */
#else
static int board_type = TANGENT;
#endif

static int io = 0x240;          /* Default IO for Dayna */
static int irq = 5;             /* Default IRQ */

/*
 *      COPS Autoprobe information.
 *      Right now if port address is right but IRQ is not 5 this will
 *      return a 5 no matter what since we will still get a status response.
 *      Need one more additional check to narrow down after we have gotten
 *      the ioaddr. But since only other possible IRQs is 3 and 4 so no real
 *      hurry on this. I *STRONGLY* recommend using IRQ 5 for your card with
 *      this driver.
 * 
 *      This driver has 2 modes and they are: Dayna mode and Tangent mode.
 *      Each mode corresponds with the type of card. It has been found
 *      that there are 2 main types of cards and all other cards are
 *      the same and just have different names or only have minor differences
 *      such as more IO ports. As this driver is tested it will
 *      become more clear on exactly what cards are supported. The driver
 *      defaults to using Dayna mode. To change the drivers mode, simply
 *      select Dayna or Tangent mode when configuring the kernel.
 *
 *      This driver should support:
 *      TANGENT driver mode:
 *              Tangent ATB-II, Novell NL-1000, Daystar Digital LT-200,
 *              COPS LT-1
 *      DAYNA driver mode:
 *              Dayna DL2000/DaynaTalk PC (Half Length), COPS LT-95, 
 *              Farallon PhoneNET PC III, Farallon PhoneNET PC II
 *      Other cards possibly supported mode unknown though:
 *              Dayna DL2000 (Full length), COPS LT/M (Micro-Channel)
 *
 *      Cards NOT supported by this driver but supported by the ltpc.c
 *      driver written by Bradford W. Johnson <johns393@maroon.tc.umn.edu>
 *              Farallon PhoneNET PC
 *              Original Apple LocalTalk PC card
 * 
 *      N.B.
 *
 *      The Daystar Digital LT200 boards do not support interrupt-driven
 *      IO.  You must specify 'irq=0xff' as a module parameter to invoke
 *      polled mode.  I also believe that the port probing logic is quite
 *      dangerous at best and certainly hopeless for a polled card.  Best to 
 *      specify both. - Steve H.
 *
 */

/*
 * Zero terminated list of IO ports to probe.
 */

static unsigned int ports[] = { 
        0x240, 0x340, 0x200, 0x210, 0x220, 0x230, 0x260, 
        0x2A0, 0x300, 0x310, 0x320, 0x330, 0x350, 0x360,
        0
};

/*
 * Zero terminated list of IRQ ports to probe.
 */

static int cops_irqlist[] = {
        5, 4, 3, 0 
};

static struct timer_list cops_timer;
static struct net_device *cops_timer_dev;

/* use 0 for production, 1 for verification, 2 for debug, 3 for verbose debug */
#ifndef COPS_DEBUG
#define COPS_DEBUG 1 
#endif
static unsigned int cops_debug = COPS_DEBUG;

/* The number of low I/O ports used by the card. */
#define COPS_IO_EXTENT       8

/* Information that needs to be kept for each board. */

struct cops_local
{
        int board;                      /* Holds what board type is. */
        int nodeid;                     /* Set to 1 once have nodeid. */
        unsigned char node_acquire;     /* Node ID when acquired. */
        struct atalk_addr node_addr;    /* Full node address */
        spinlock_t lock;                /* RX/TX lock */
};

/* Index to functions, as function prototypes. */
static int  cops_probe1 (struct net_device *dev, int ioaddr);
static int  cops_irq (int ioaddr, int board);

static int  cops_open (struct net_device *dev);
static int  cops_jumpstart (struct net_device *dev);
static void cops_reset (struct net_device *dev, int sleep);
static void cops_load (struct net_device *dev);
static int  cops_nodeid (struct net_device *dev, int nodeid);

static irqreturn_t cops_interrupt (int irq, void *dev_id);
static void cops_poll(struct timer_list *t);
static void cops_timeout(struct net_device *dev, unsigned int txqueue);
static void cops_rx (struct net_device *dev);
static netdev_tx_t  cops_send_packet (struct sk_buff *skb,
                                            struct net_device *dev);
static void set_multicast_list (struct net_device *dev);
static int  cops_ioctl (struct net_device *dev, struct ifreq *rq, int cmd);
static int  cops_close (struct net_device *dev);

static void cleanup_card(struct net_device *dev)
{
        if (dev->irq)
                free_irq(dev->irq, dev);
        release_region(dev->base_addr, COPS_IO_EXTENT);
}

/*
 *      Check for a network adaptor of this type, and return '0' iff one exists.
 *      If dev->base_addr == 0, probe all likely locations.
 *      If dev->base_addr in [1..0x1ff], always return failure.
 *        otherwise go with what we pass in.
 */
struct net_device * __init cops_probe(int unit)
{
        struct net_device *dev;
        unsigned *port;
        int base_addr;
        int err = 0;

        dev = alloc_ltalkdev(sizeof(struct cops_local));
        if (!dev)
                return ERR_PTR(-ENOMEM);

        if (unit >= 0) {
                sprintf(dev->name, "lt%d", unit);
                netdev_boot_setup_check(dev);
                irq = dev->irq;
                base_addr = dev->base_addr;
        } else {
                base_addr = dev->base_addr = io;
        }

        if (base_addr > 0x1ff) {    /* Check a single specified location. */
                err = cops_probe1(dev, base_addr);
        } else if (base_addr != 0) { /* Don't probe at all. */
                err = -ENXIO;
        } else {
                /* FIXME  Does this really work for cards which generate irq?
                 * It's definitely N.G. for polled Tangent. sh
                 * Dayna cards don't autoprobe well at all, but if your card is
                 * at IRQ 5 & IO 0x240 we find it every time. ;) JS
                 */
                for (port = ports; *port && cops_probe1(dev, *port) < 0; port++)
                        ;
                if (!*port)
                        err = -ENODEV;
        }
        if (err)
                goto out;
        err = register_netdev(dev);
        if (err)
                goto out1;
        return dev;
out1:
        cleanup_card(dev);
out:
        free_netdev(dev);
        return ERR_PTR(err);
}

static const struct net_device_ops cops_netdev_ops = {
        .ndo_open               = cops_open,
        .ndo_stop               = cops_close,
        .ndo_start_xmit         = cops_send_packet,
        .ndo_tx_timeout         = cops_timeout,
        .ndo_do_ioctl           = cops_ioctl,
        .ndo_set_rx_mode        = set_multicast_list,
};

/*
 *      This is the real probe routine. Linux has a history of friendly device
 *      probes on the ISA bus. A good device probes avoids doing writes, and
 *      verifies that the correct device exists and functions.
 */
static int __init cops_probe1(struct net_device *dev, int ioaddr)
{
        struct cops_local *lp;
        static unsigned version_printed;
        int board = board_type;
        int retval;
        
        if(cops_debug && version_printed++ == 0)
                printk("%s", version);

        /* Grab the region so no one else tries to probe our ioports. */
        if (!request_region(ioaddr, COPS_IO_EXTENT, dev->name))
                return -EBUSY;

        /*
         * Since this board has jumpered interrupts, allocate the interrupt
         * vector now. There is no point in waiting since no other device
         * can use the interrupt, and this marks the irq as busy. Jumpered
         * interrupts are typically not reported by the boards, and we must
         * used AutoIRQ to find them.
         */
        dev->irq = irq;
        switch (dev->irq)
        {
                case 0:
                        /* COPS AutoIRQ routine */
                        dev->irq = cops_irq(ioaddr, board);
                        if (dev->irq)
                                break;
                        /* fall through - Once no IRQ found on this port. */
                case 1:
                        retval = -EINVAL;
                        goto err_out;

                /* Fixup for users that don't know that IRQ 2 is really
                 * IRQ 9, or don't know which one to set.
                 */
                case 2:
                        dev->irq = 9;
                        break;

                /* Polled operation requested. Although irq of zero passed as
                 * a parameter tells the init routines to probe, we'll
                 * overload it to denote polled operation at runtime.
                 */
                case 0xff:
                        dev->irq = 0;
                        break;

                default:
                        break;
        }

        /* Reserve any actual interrupt. */
        if (dev->irq) {
                retval = request_irq(dev->irq, cops_interrupt, 0, dev->name, dev);
                if (retval)
                        goto err_out;
        }

        dev->base_addr = ioaddr;

        lp = netdev_priv(dev);
        spin_lock_init(&lp->lock);

        /* Copy local board variable to lp struct. */
        lp->board               = board;

        dev->netdev_ops         = &cops_netdev_ops;
        dev->watchdog_timeo     = HZ * 2;


        /* Tell the user where the card is and what mode we're in. */
        if(board==DAYNA)
                printk("%s: %s at %#3x, using IRQ %d, in Dayna mode.\n", 
                        dev->name, cardname, ioaddr, dev->irq);
        if(board==TANGENT) {
                if(dev->irq)
                        printk("%s: %s at %#3x, IRQ %d, in Tangent mode\n", 
                                dev->name, cardname, ioaddr, dev->irq);
                else
                        printk("%s: %s at %#3x, using polled IO, in Tangent mode.\n", 
                                dev->name, cardname, ioaddr);

        }
        return 0;

err_out:
        release_region(ioaddr, COPS_IO_EXTENT);
        return retval;
}

static int __init cops_irq (int ioaddr, int board)
{       /*
         * This does not use the IRQ to determine where the IRQ is. We just
         * assume that when we get a correct status response that it's the IRQ.
         * This really just verifies the IO port but since we only have access
         * to such a small number of IRQs (5, 4, 3) this is not bad.
         * This will probably not work for more than one card.
         */
        int irqaddr=0;
        int i, x, status;

        if(board==DAYNA)
        {
                outb(0, ioaddr+DAYNA_RESET);
                inb(ioaddr+DAYNA_RESET);
                mdelay(333);
        }
        if(board==TANGENT)
        {
                inb(ioaddr);
                outb(0, ioaddr);
                outb(0, ioaddr+TANG_RESET);
        }

        for(i=0; cops_irqlist[i] !=0; i++)
        {
                irqaddr = cops_irqlist[i];
                for(x = 0xFFFF; x>0; x --)    /* wait for response */
                {
                        if(board==DAYNA)
                        {
                                status = (inb(ioaddr+DAYNA_CARD_STATUS)&3);
                                if(status == 1)
                                        return irqaddr;
                        }
                        if(board==TANGENT)
                        {
                                if((inb(ioaddr+TANG_CARD_STATUS)& TANG_TX_READY) !=0)
                                        return irqaddr;
                        }
                }
        }
        return 0;       /* no IRQ found */
}

/*
 * Open/initialize the board. This is called (in the current kernel)
 * sometime after booting when the 'ifconfig' program is run.
 */
static int cops_open(struct net_device *dev)
{
    struct cops_local *lp = netdev_priv(dev);

        if(dev->irq==0)
        {
                /*
                 * I don't know if the Dayna-style boards support polled 
                 * operation.  For now, only allow it for Tangent.
                 */
                if(lp->board==TANGENT)  /* Poll 20 times per second */
                {
                    cops_timer_dev = dev;
                    timer_setup(&cops_timer, cops_poll, 0);
                    cops_timer.expires  = jiffies + HZ/20;
                    add_timer(&cops_timer);
                } 
                else 
                {
                        printk(KERN_WARNING "%s: No irq line set\n", dev->name);
                        return -EAGAIN;
                }
        }

        cops_jumpstart(dev);    /* Start the card up. */

        netif_start_queue(dev);
        return 0;
}

/*
 *      This allows for a dynamic start/restart of the entire card.
 */
static int cops_jumpstart(struct net_device *dev)
{
        struct cops_local *lp = netdev_priv(dev);

        /*
         *      Once the card has the firmware loaded and has acquired
         *      the nodeid, if it is reset it will lose it all.
         */
        cops_reset(dev,1);      /* Need to reset card before load firmware. */
        cops_load(dev);         /* Load the firmware. */

        /*
         *      If atalkd already gave us a nodeid we will use that
         *      one again, else we wait for atalkd to give us a nodeid
         *      in cops_ioctl. This may cause a problem if someone steals
         *      our nodeid while we are resetting.
         */     
        if(lp->nodeid == 1)
                cops_nodeid(dev,lp->node_acquire);

        return 0;
}

static void tangent_wait_reset(int ioaddr)
{
        int timeout=0;

        while(timeout++ < 5 && (inb(ioaddr+TANG_CARD_STATUS)&TANG_TX_READY)==0)
                mdelay(1);   /* Wait 1 second */
}

/*
 *      Reset the LocalTalk board.
 */
static void cops_reset(struct net_device *dev, int sleep)
{
        struct cops_local *lp = netdev_priv(dev);
        int ioaddr=dev->base_addr;

        if(lp->board==TANGENT)
        {
                inb(ioaddr);            /* Clear request latch. */
                outb(0,ioaddr);         /* Clear the TANG_TX_READY flop. */
                outb(0, ioaddr+TANG_RESET);     /* Reset the adapter. */

                tangent_wait_reset(ioaddr);
                outb(0, ioaddr+TANG_CLEAR_INT);
        }
        if(lp->board==DAYNA)
        {
                outb(0, ioaddr+DAYNA_RESET);    /* Assert the reset port */
                inb(ioaddr+DAYNA_RESET);        /* Clear the reset */
                if (sleep)
                        msleep(333);
                else
                        mdelay(333);
        }

        netif_wake_queue(dev);
}

static void cops_load (struct net_device *dev)
{
        struct ifreq ifr;
        struct ltfirmware *ltf= (struct ltfirmware *)&ifr.ifr_ifru;
        struct cops_local *lp = netdev_priv(dev);
        int ioaddr=dev->base_addr;
        int length, i = 0;

        strcpy(ifr.ifr_name,"lt0");

        /* Get card's firmware code and do some checks on it. */
#ifdef CONFIG_COPS_DAYNA        
        if(lp->board==DAYNA)
        {
                ltf->length=sizeof(ffdrv_code);
                ltf->data=ffdrv_code;
        }
        else
#endif        
#ifdef CONFIG_COPS_TANGENT
        if(lp->board==TANGENT)
        {
                ltf->length=sizeof(ltdrv_code);
                ltf->data=ltdrv_code;
        }
        else
#endif
        {
                printk(KERN_INFO "%s; unsupported board type.\n", dev->name);
                return;
        }
        
        /* Check to make sure firmware is correct length. */
        if(lp->board==DAYNA && ltf->length!=5983)
        {
                printk(KERN_WARNING "%s: Firmware is not length of FFDRV.BIN.\n", dev->name);
                return;
        }
        if(lp->board==TANGENT && ltf->length!=2501)
        {
                printk(KERN_WARNING "%s: Firmware is not length of DRVCODE.BIN.\n", dev->name);
                return;
        }

        if(lp->board==DAYNA)
        {
                /*
                 *      We must wait for a status response
                 *      with the DAYNA board.
                 */
                while(++i<65536)
                {
                       if((inb(ioaddr+DAYNA_CARD_STATUS)&3)==1)
                                break;
                }

                if(i==65536)
                        return;
        }

        /*
         *      Upload the firmware and kick. Byte-by-byte works nicely here.
         */
        i=0;
        length = ltf->length;
        while(length--)
        {
                outb(ltf->data[i], ioaddr);
                i++;
        }

        if(cops_debug > 1)
                printk("%s: Uploaded firmware - %d bytes of %d bytes.\n", 
                        dev->name, i, ltf->length);

        if(lp->board==DAYNA)    /* Tell Dayna to run the firmware code. */
                outb(1, ioaddr+DAYNA_INT_CARD);
        else                    /* Tell Tang to run the firmware code. */
                inb(ioaddr);

        if(lp->board==TANGENT)
        {
                tangent_wait_reset(ioaddr);
                inb(ioaddr);    /* Clear initial ready signal. */
        }
}

/*
 *      Get the LocalTalk Nodeid from the card. We can suggest
 *      any nodeid 1-254. The card will try and get that exact
 *      address else we can specify 0 as the nodeid and the card
 *      will autoprobe for a nodeid.
 */
static int cops_nodeid (struct net_device *dev, int nodeid)
{
        struct cops_local *lp = netdev_priv(dev);
        int ioaddr = dev->base_addr;

        if(lp->board == DAYNA)
        {
                /* Empty any pending adapter responses. */
                while((inb(ioaddr+DAYNA_CARD_STATUS)&DAYNA_TX_READY)==0)
                {
                        outb(0, ioaddr+COPS_CLEAR_INT); /* Clear interrupts. */
                        if((inb(ioaddr+DAYNA_CARD_STATUS)&0x03)==DAYNA_RX_REQUEST)
                                cops_rx(dev);   /* Kick any packets waiting. */
                        schedule();
                }

                outb(2, ioaddr);        /* Output command packet length as 2. */
                outb(0, ioaddr);
                outb(LAP_INIT, ioaddr); /* Send LAP_INIT command byte. */
                outb(nodeid, ioaddr);   /* Suggest node address. */
        }

        if(lp->board == TANGENT)
        {
                /* Empty any pending adapter responses. */
                while(inb(ioaddr+TANG_CARD_STATUS)&TANG_RX_READY)
                {
                        outb(0, ioaddr+COPS_CLEAR_INT); /* Clear interrupt. */
                        cops_rx(dev);           /* Kick out packets waiting. */
                        schedule();
                }

                /* Not sure what Tangent does if nodeid picked is used. */
                if(nodeid == 0)                         /* Seed. */
                        nodeid = jiffies&0xFF;          /* Get a random try */
                outb(2, ioaddr);                        /* Command length LSB */
                outb(0, ioaddr);                        /* Command length MSB */
                outb(LAP_INIT, ioaddr);                 /* Send LAP_INIT byte */
                outb(nodeid, ioaddr);                   /* LAP address hint. */
                outb(0xFF, ioaddr);                     /* Int. level to use */
        }

        lp->node_acquire=0;             /* Set nodeid holder to 0. */
        while(lp->node_acquire==0)      /* Get *True* nodeid finally. */
        {
                outb(0, ioaddr+COPS_CLEAR_INT); /* Clear any interrupt. */

                if(lp->board == DAYNA)
                {
                        if((inb(ioaddr+DAYNA_CARD_STATUS)&0x03)==DAYNA_RX_REQUEST)
                                cops_rx(dev);   /* Grab the nodeid put in lp->node_acquire. */
                }
                if(lp->board == TANGENT)
                {       
                        if(inb(ioaddr+TANG_CARD_STATUS)&TANG_RX_READY)
                                cops_rx(dev);   /* Grab the nodeid put in lp->node_acquire. */
                }
                schedule();
        }

        if(cops_debug > 1)
                printk(KERN_DEBUG "%s: Node ID %d has been acquired.\n", 
                        dev->name, lp->node_acquire);

        lp->nodeid=1;   /* Set got nodeid to 1. */

        return 0;
}

/*
 *      Poll the Tangent type cards to see if we have work.
 */
 
static void cops_poll(struct timer_list *unused)
{
        int ioaddr, status;
        int boguscount = 0;
        struct net_device *dev = cops_timer_dev;

        del_timer(&cops_timer);

        if(dev == NULL)
                return; /* We've been downed */

        ioaddr = dev->base_addr;
        do {
                status=inb(ioaddr+TANG_CARD_STATUS);
                if(status & TANG_RX_READY)
                        cops_rx(dev);
                if(status & TANG_TX_READY)
                        netif_wake_queue(dev);
                status = inb(ioaddr+TANG_CARD_STATUS);
        } while((++boguscount < 20) && (status&(TANG_RX_READY|TANG_TX_READY)));

        /* poll 20 times per second */
        cops_timer.expires = jiffies + HZ/20;
        add_timer(&cops_timer);
}

/*
 *      The typical workload of the driver:
 *      Handle the network interface interrupts.
 */
static irqreturn_t cops_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;
        struct cops_local *lp;
        int ioaddr, status;
        int boguscount = 0;

        ioaddr = dev->base_addr;
        lp = netdev_priv(dev);

        if(lp->board==DAYNA)
        {
                do {
                        outb(0, ioaddr + COPS_CLEAR_INT);
                        status=inb(ioaddr+DAYNA_CARD_STATUS);
                        if((status&0x03)==DAYNA_RX_REQUEST)
                                cops_rx(dev);
                        netif_wake_queue(dev);
                } while(++boguscount < 20);
        }
        else
        {
                do {
                        status=inb(ioaddr+TANG_CARD_STATUS);
                        if(status & TANG_RX_READY)
                                cops_rx(dev);
                        if(status & TANG_TX_READY)
                                netif_wake_queue(dev);
                        status=inb(ioaddr+TANG_CARD_STATUS);
                } while((++boguscount < 20) && (status&(TANG_RX_READY|TANG_TX_READY)));
        }

        return IRQ_HANDLED;
}

/*
 *      We have a good packet(s), get it/them out of the buffers.
 */
static void cops_rx(struct net_device *dev)
{
        int pkt_len = 0;
        int rsp_type = 0;
        struct sk_buff *skb = NULL;
        struct cops_local *lp = netdev_priv(dev);
        int ioaddr = dev->base_addr;
        int boguscount = 0;
        unsigned long flags;


        spin_lock_irqsave(&lp->lock, flags);
        
        if(lp->board==DAYNA)
        {
                outb(0, ioaddr);                /* Send out Zero length. */
                outb(0, ioaddr);
                outb(DATA_READ, ioaddr);        /* Send read command out. */

                /* Wait for DMA to turn around. */
                while(++boguscount<1000000)
                {
                        barrier();
                        if((inb(ioaddr+DAYNA_CARD_STATUS)&0x03)==DAYNA_RX_READY)
                                break;
                }

                if(boguscount==1000000)
                {
                        printk(KERN_WARNING "%s: DMA timed out.\n",dev->name);
                        spin_unlock_irqrestore(&lp->lock, flags);
                        return;
                }
        }

        /* Get response length. */
        pkt_len = inb(ioaddr);
        pkt_len |= (inb(ioaddr) << 8);
        /* Input IO code. */
        rsp_type=inb(ioaddr);

        /* Malloc up new buffer. */
        skb = dev_alloc_skb(pkt_len);
        if(skb == NULL)
        {
                printk(KERN_WARNING "%s: Memory squeeze, dropping packet.\n",
                        dev->name);
                dev->stats.rx_dropped++;
                while(pkt_len--)        /* Discard packet */
                        inb(ioaddr);
                spin_unlock_irqrestore(&lp->lock, flags);
                return;
        }
        skb->dev = dev;
        skb_put(skb, pkt_len);
        skb->protocol = htons(ETH_P_LOCALTALK);

        insb(ioaddr, skb->data, pkt_len);               /* Eat the Data */

        if(lp->board==DAYNA)
                outb(1, ioaddr+DAYNA_INT_CARD);         /* Interrupt the card */

        spin_unlock_irqrestore(&lp->lock, flags);  /* Restore interrupts. */

        /* Check for bad response length */
        if(pkt_len < 0 || pkt_len > MAX_LLAP_SIZE)
        {
                printk(KERN_WARNING "%s: Bad packet length of %d bytes.\n", 
                        dev->name, pkt_len);
                dev->stats.tx_errors++;
                dev_kfree_skb_any(skb);
                return;
        }

        /* Set nodeid and then get out. */
        if(rsp_type == LAP_INIT_RSP)
        {       /* Nodeid taken from received packet. */
                lp->node_acquire = skb->data[0];
                dev_kfree_skb_any(skb);
                return;
        }

        /* One last check to make sure we have a good packet. */
        if(rsp_type != LAP_RESPONSE)
        {
                printk(KERN_WARNING "%s: Bad packet type %d.\n", dev->name, rsp_type);
                dev->stats.tx_errors++;
                dev_kfree_skb_any(skb);
                return;
        }

        skb_reset_mac_header(skb);    /* Point to entire packet. */
        skb_pull(skb,3);
        skb_reset_transport_header(skb);    /* Point to data (Skip header). */

        /* Update the counters. */
        dev->stats.rx_packets++;
        dev->stats.rx_bytes += skb->len;

        /* Send packet to a higher place. */
        netif_rx(skb);
}

static void cops_timeout(struct net_device *dev, unsigned int txqueue)
{
        struct cops_local *lp = netdev_priv(dev);
        int ioaddr = dev->base_addr;

        dev->stats.tx_errors++;
        if(lp->board==TANGENT)
        {
                if((inb(ioaddr+TANG_CARD_STATUS)&TANG_TX_READY)==0)
                        printk(KERN_WARNING "%s: No TX complete interrupt.\n", dev->name);
        }
        printk(KERN_WARNING "%s: Transmit timed out.\n", dev->name);
        cops_jumpstart(dev);    /* Restart the card. */
        netif_trans_update(dev); /* prevent tx timeout */
        netif_wake_queue(dev);
}


/*
 *      Make the card transmit a LocalTalk packet.
 */

static netdev_tx_t cops_send_packet(struct sk_buff *skb,
                                          struct net_device *dev)
{
        struct cops_local *lp = netdev_priv(dev);
        int ioaddr = dev->base_addr;
        unsigned long flags;

        /*
         * Block a timer-based transmit from overlapping. 
         */
         
        netif_stop_queue(dev);

        spin_lock_irqsave(&lp->lock, flags);
        if(lp->board == DAYNA)   /* Wait for adapter transmit buffer. */
                while((inb(ioaddr+DAYNA_CARD_STATUS)&DAYNA_TX_READY)==0)
                        cpu_relax();
        if(lp->board == TANGENT) /* Wait for adapter transmit buffer. */
                while((inb(ioaddr+TANG_CARD_STATUS)&TANG_TX_READY)==0)
                        cpu_relax();

        /* Output IO length. */
        outb(skb->len, ioaddr);
        outb(skb->len >> 8, ioaddr);

        /* Output IO code. */
        outb(LAP_WRITE, ioaddr);

        if(lp->board == DAYNA)  /* Check the transmit buffer again. */
                while((inb(ioaddr+DAYNA_CARD_STATUS)&DAYNA_TX_READY)==0);

        outsb(ioaddr, skb->data, skb->len);     /* Send out the data. */

        if(lp->board==DAYNA)    /* Dayna requires you kick the card */
                outb(1, ioaddr+DAYNA_INT_CARD);

        spin_unlock_irqrestore(&lp->lock, flags);       /* Restore interrupts. */

        /* Done sending packet, update counters and cleanup. */
        dev->stats.tx_packets++;
        dev->stats.tx_bytes += skb->len;
        dev_kfree_skb (skb);
        return NETDEV_TX_OK;
}

/*
 *      Dummy function to keep the Appletalk layer happy.
 */
 
static void set_multicast_list(struct net_device *dev)
{
        if(cops_debug >= 3)
                printk("%s: set_multicast_list executed\n", dev->name);
}

/*
 *      System ioctls for the COPS LocalTalk card.
 */
 
static int cops_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
        struct cops_local *lp = netdev_priv(dev);
        struct sockaddr_at *sa = (struct sockaddr_at *)&ifr->ifr_addr;
        struct atalk_addr *aa = &lp->node_addr;

        switch(cmd)
        {
                case SIOCSIFADDR:
                        /* Get and set the nodeid and network # atalkd wants. */
                        cops_nodeid(dev, sa->sat_addr.s_node);
                        aa->s_net               = sa->sat_addr.s_net;
                        aa->s_node              = lp->node_acquire;

                        /* Set broardcast address. */
                        dev->broadcast[0]       = 0xFF;
                        
                        /* Set hardware address. */
                        dev->dev_addr[0]        = aa->s_node;
                        dev->addr_len           = 1;
                        return 0;

                case SIOCGIFADDR:
                        sa->sat_addr.s_net      = aa->s_net;
                        sa->sat_addr.s_node     = aa->s_node;
                        return 0;

                default:
                        return -EOPNOTSUPP;
        }
}

/*
 *      The inverse routine to cops_open().
 */
 
static int cops_close(struct net_device *dev)
{
        struct cops_local *lp = netdev_priv(dev);

        /* If we were running polled, yank the timer.
         */
        if(lp->board==TANGENT && dev->irq==0)
                del_timer(&cops_timer);

        netif_stop_queue(dev);
        return 0;
}


#ifdef MODULE
static struct net_device *cops_dev;

MODULE_LICENSE("GPL");
module_param_hw(io, int, ioport, 0);
module_param_hw(irq, int, irq, 0);
module_param_hw(board_type, int, other, 0);

static int __init cops_module_init(void)
{
        if (io == 0)
                printk(KERN_WARNING "%s: You shouldn't autoprobe with insmod\n",
                        cardname);
        cops_dev = cops_probe(-1);
        return PTR_ERR_OR_ZERO(cops_dev);
}

static void __exit cops_module_exit(void)
{
        unregister_netdev(cops_dev);
        cleanup_card(cops_dev);
        free_netdev(cops_dev);
}
module_init(cops_module_init);
module_exit(cops_module_exit);
#endif /* MODULE */