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/* pcnet32.c: An AMD PCnet32 ethernet driver for linux. */

/*

 *  Copyright 1996,97 Thomas Bogendoerfer, 1993-1995,1998 Donald Becker

 *      Copyright 1993 United States Government as represented by the

 *      Director, National Security Agency.

 *

 *      Derived from the lance driver written 1993-1995 by Donald Becker.

 *

 *      This software may be used and distributed according to the terms

 *      of the GNU Public License, incorporated herein by reference.

 *

 *      This driver is for AMD PCnet-PCI based ethercards

 */

static const char *version = "pcnet32.c:v0.99B 4/4/98 DJBecker/TSBogend.\n";

/* A few user-configurable values. */

/* Maximum events (Rx packets, etc.) to handle at each interrupt. */

static int max_interrupt_work = 20;

/*

 * Set the number of Tx and Rx buffers, using Log_2(# buffers).

 * Reasonable default values are 4 Tx buffers, and 16 Rx buffers.

 * That translates to 2 (4 == 2^^2) and 4 (16 == 2^^4).

 */

#define PCNET_LOG_TX_BUFFERS 4

#define PCNET_LOG_RX_BUFFERS 4

#ifdef MODULE

#ifdef MODVERSIONS

#include <linux/modversions.h>

#endif

#include <linux/module.h>

#include <linux/version.h>

#else

#define MOD_INC_USE_COUNT

#define MOD_DEC_USE_COUNT

#endif

#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/pci.h>

#include <linux/bios32.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>

/* Driver verbosity level.  0 = no messages, 7 = wordy death.

   Modify here, or when loading as a module. */

static int pcnet32_debug = 1;

/*

 *                              Theory of Operation

 *

 * This driver uses the same software structure as the normal lance

 * driver. So look for a verbose description in lance.c. The differences

 * to the normal lance driver is the use of the 32bit mode of PCnet32

 * and PCnetPCI chips. Because these chips are 32bit chips, there is no

 * 16MB limitation and we don't need bounce buffers.

 */

/*

 * History:

 * v0.01:  Initial version

 *         only tested on Alpha Noname Board

 * v0.02:  changed IRQ handling for new interrupt scheme (dev_id)

 *         tested on a ASUS SP3G

 * v0.10:  fixed an odd problem with the 79C794 in a Compaq Deskpro XL

 *         looks like the 974 doesn't like stopping and restarting in a

 *         short period of time; now we do a reinit of the lance; the

 *         bug was triggered by doing ifconfig eth0 <ip> broadcast <addr>

 *         and hangs the machine (thanks to Klaus Liedl for debugging)

 * v0.12:  by suggestion from Donald Becker: Renamed driver to pcnet32,

 *         made it standalone (no need for lance.c)

 * v0.13:  added additional PCI detecting for special PCI devices (Compaq)

 * v0.14:  stripped down additional PCI probe (thanks to David C Niemi

 *         and sveneric@xs4all.nl for testing this on their Compaq boxes)

 * v0.15:  added 79C965 (VLB) probe

 *         added interrupt sharing for PCI chips

 * v0.16:  fixed set_multicast_list on Alpha machines

 * v0.17:  removed hack from dev.c; now pcnet32 uses ethif_probe in Space.c

 * v0.19:  changed setting of autoselect bit

 * v0.20:  removed additional Compaq PCI probe; there is now a working one

 *         in arch/i386/bios32.c

 * v0.21:  added endian conversion for ppc, from work by cort@cs.nmt.edu

 * v0.22:  added printing of status to ring dump

 * v0.23:  changed enet_statistics to net_devive_stats

 * v0.99: Changes for 2.0.34 final release. -djb

 */

#ifndef __powerpc__

#define le16_to_cpu(val)  (val)

#define le32_to_cpu(val)  (val)

#endif

#if (LINUX_VERSION_CODE < 0x20123)

#define test_and_set_bit(val, addr) set_bit(val, addr)

#endif

#define TX_RING_SIZE                    (1 << (PCNET_LOG_TX_BUFFERS))

#define TX_RING_MOD_MASK                (TX_RING_SIZE - 1)

#define TX_RING_LEN_BITS                ((PCNET_LOG_TX_BUFFERS) << 12)

#define RX_RING_SIZE                    (1 << (PCNET_LOG_RX_BUFFERS))

#define RX_RING_MOD_MASK                (RX_RING_SIZE - 1)

#define RX_RING_LEN_BITS                ((PCNET_LOG_RX_BUFFERS) << 4)

#define PKT_BUF_SZ              1544

/* Offsets from base I/O address. */

enum pcnet_offsets { PCNET32_DATA=0x10, PCNET32_ADDR=0x12, PCNET32_RESET=0x14,

                                         PCNET32_BUS_IF=0x16,};

#define PCNET32_TOTAL_SIZE 0x20

/* The PCNET32 Rx and Tx ring descriptors. */

struct pcnet32_rx_head {

        u32 base;

        s16 buf_length;

        s16 status;

        u32 msg_length;

        u32 reserved;

};

struct pcnet32_tx_head {

        u32 base;

        s16 length;

        s16 status;

        u32 misc;

        u32 reserved;

};

/* The PCNET32 32-Bit initialization block, described in databook. */

struct pcnet32_init_block {

        u16 mode;

        u16 tlen_rlen;

        u8  phys_addr[6];

        u16 reserved;

        u32 filter[2];

        /* Receive and transmit ring base, along with extra bits. */

        u32 rx_ring;

        u32 tx_ring;

};

struct pcnet32_private {

        /* The Tx and Rx ring entries must be aligned on 16-byte boundaries

           in 32bit mode. */

        struct pcnet32_rx_head   rx_ring[RX_RING_SIZE];

        struct pcnet32_tx_head   tx_ring[TX_RING_SIZE];

        struct pcnet32_init_block       init_block;

        const char *name;

        struct device *next_module;

        /* The saved address of a sent-in-place packet/buffer, for skfree(). */

        struct sk_buff* tx_skbuff[TX_RING_SIZE];

        unsigned long rx_buffs;         /* Address of Rx and Tx buffers. */

        int cur_rx, cur_tx;                     /* The next free ring entry */

        int dirty_rx, dirty_tx;         /* The ring entries to be free()ed. */

        struct enet_statistics stats;

        char tx_full;

        unsigned long lock;

};

static struct pcnet_chip_type {

        int id_number;

        const char *name;

        int flags;

} chip_table[] = {

        {0x2420, "PCnet/PCI 79C970", 0},

        {0x2430, "PCnet32", 0},

        {0x2621, "PCnet/PCI II 79C970A", 0},

        {0x2623, "PCnet/FAST 79C971", 0},

        {0x2624, "PCnet/FAST+ 79C972", 0},

        {0x0,    "PCnet32 (unknown)", 0},

};

/* Index of functions. */

int  pcnet32_probe(struct device *dev);

static int  pcnet32_probe1(struct device *dev, unsigned int ioaddr, unsigned char irq_line);

static int  pcnet32_open(struct device *dev);

static void pcnet32_init_ring(struct device *dev);

static int  pcnet32_start_xmit(struct sk_buff *skb, struct device *dev);

static int  pcnet32_rx(struct device *dev);

static void pcnet32_interrupt(int irq, void *dev_id, struct pt_regs *regs);

static int  pcnet32_close(struct device *dev);

static struct enet_statistics *pcnet32_get_stats(struct device *dev);

static void pcnet32_set_multicast_list(struct device *dev);

/* A list of all installed PCnet32 devices, for removing the driver module. */

static struct device *root_pcnet32_dev = NULL;

int pcnet32_probe (struct device *dev)

{

        static int pci_index = 0;        /* Static, for multiple probe calls. */

        int cards_found = 0;

        if ( ! pcibios_present())

                return ENODEV;

        for (;pci_index < 0xff; pci_index++) {

                u8 irq_line;

                u16 pci_command, new_command;

                unsigned char pci_bus, pci_device_fn;

                u32 pci_ioaddr;

                if (pcibios_find_device (PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_LANCE,

                                                                 pci_index, &pci_bus, &pci_device_fn)

                        != PCIBIOS_SUCCESSFUL)

                        break;

                pcibios_read_config_byte(pci_bus, pci_device_fn,

                                                                 PCI_INTERRUPT_LINE, &irq_line);

                pcibios_read_config_dword(pci_bus, pci_device_fn,

                                                                  PCI_BASE_ADDRESS_0, &pci_ioaddr);

                /* Remove I/O space marker in bit 0. */

                pci_ioaddr &= ~3;

                /* Avoid already found cards from previous pcnet32_probe() calls */

                if (check_region(pci_ioaddr, PCNET32_TOTAL_SIZE))

                        continue;

                /* Activate the card: fix for brain-damaged Win98 BIOSes. */

                pcibios_read_config_word(pci_bus, pci_device_fn,

                                                                 PCI_COMMAND, &pci_command);

                new_command = pci_command | PCI_COMMAND_MASTER|PCI_COMMAND_IO;

                if (pci_command != new_command) {

                        printk(KERN_INFO "  The PCI BIOS has not enabled the AMD Ethernet"

                                   " device at %2x-%2x."

                                   "  Updating PCI command %4.4x->%4.4x.\n",

                                   pci_bus, pci_device_fn, pci_command, new_command);

                        pcibios_write_config_word(pci_bus, pci_device_fn,

                                                                          PCI_COMMAND, new_command);

                }

                if (pcnet32_probe1(dev, pci_ioaddr, irq_line) != 0) {

                        /* Should never happen. */

                        printk(KERN_ERR "pcnet32.c: Probe of PCI card at %#x failed.\n",

                                   pci_ioaddr);

                } else

                        dev = 0;

                cards_found++;

        }

        return cards_found ? 0 : -ENODEV;

}

/* pcnet32_probe1 */

static int pcnet32_probe1(struct device *dev, unsigned int ioaddr, unsigned char irq_line)

{

        struct pcnet32_private *lp;

        int i;

        const char *chipname;

        /* check if there is really a pcnet chip on that ioaddr */

        if ((inb(ioaddr + 14) != 0x57) || (inb(ioaddr + 15) != 0x57))

                return ENODEV;

        inw(ioaddr+PCNET32_RESET); /* Reset the PCNET32 */

        outw(0x0000, ioaddr+PCNET32_ADDR); /* Switch to window 0 */

        if (inw(ioaddr+PCNET32_DATA) != 0x0004)

                return ENODEV;

        /* Get the version of the chip. */

        outw(88, ioaddr+PCNET32_ADDR);

        if (inw(ioaddr+PCNET32_ADDR) != 88) {

                /* should never happen */

                return ENODEV;

        } else {                        /* Good, it's a newer chip. */

                int chip_version = inw(ioaddr+PCNET32_DATA);

                outw(89, ioaddr+PCNET32_ADDR);

                chip_version |= inw(ioaddr+PCNET32_DATA) << 16;

                if (pcnet32_debug > 2)

                        printk("  PCnet chip version is %#x.\n", chip_version);

                if ((chip_version & 0xfff) != 0x003)

                        return ENODEV;

                chip_version = (chip_version >> 12) & 0xffff;

                for (i = 0; chip_table[i].id_number; i++)

                        if (chip_table[i].id_number == chip_version)

                                break;

                chipname = chip_table[i].name;

        }

        dev = init_etherdev(dev, 0);

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

        /* There is a 16 byte station address PROM at the base address.

           The first six bytes are the station address. */

        for (i = 0; i < 6; i++)

                printk(" %2.2x", dev->dev_addr[i] = inb(ioaddr + i));

        printk("\n");

        dev->base_addr = ioaddr;

        request_region(ioaddr, PCNET32_TOTAL_SIZE, dev->name);

        /* Data structures used by the PCnet32 are 16byte aligned and DMAble. */

    lp = (struct pcnet32_private *)

                (((unsigned long)kmalloc(sizeof(*lp)+15, GFP_DMA | GFP_KERNEL)+15) & ~15);

    memset(lp, 0, sizeof(*lp));

        dev->priv = lp;

        lp->next_module = root_pcnet32_dev;

        root_pcnet32_dev = dev;

    lp->name = chipname;

    lp->rx_buffs = (unsigned long) kmalloc(PKT_BUF_SZ*RX_RING_SIZE, GFP_DMA | GFP_KERNEL);

    lp->init_block.mode = le16_to_cpu(0x0003);  /* Disable Rx and Tx. */

    lp->init_block.tlen_rlen = le16_to_cpu(TX_RING_LEN_BITS | RX_RING_LEN_BITS);

    for (i = 0; i < 6; i++)

      lp->init_block.phys_addr[i] = dev->dev_addr[i];

    lp->init_block.filter[0] = 0x00000000;

    lp->init_block.filter[1] = 0x00000000;

    lp->init_block.rx_ring = (u32)le32_to_cpu(virt_to_bus(lp->rx_ring));

    lp->init_block.tx_ring = (u32)le32_to_cpu(virt_to_bus(lp->tx_ring));

    /* switch pcnet32 to 32bit mode */

    outw(0x0014, ioaddr+PCNET32_ADDR);

    outw(0x0002, ioaddr+PCNET32_BUS_IF);

    outw(0x0001, ioaddr+PCNET32_ADDR);

    inw(ioaddr+PCNET32_ADDR);

    outw(virt_to_bus(&lp->init_block) & 0xffff, ioaddr+PCNET32_DATA);

    outw(0x0002, ioaddr+PCNET32_ADDR);

    inw(ioaddr+PCNET32_ADDR);

    outw(virt_to_bus(&lp->init_block) >> 16, ioaddr+PCNET32_DATA);

    outw(0x0000, ioaddr+PCNET32_ADDR);

    inw(ioaddr+PCNET32_ADDR);

    dev->irq = irq_line;

    if (pcnet32_debug > 0)

      printk(version);

    /* The PCNET32-specific entries in the device structure. */

    dev->open = &pcnet32_open;

    dev->hard_start_xmit = &pcnet32_start_xmit;

    dev->stop = &pcnet32_close;

    dev->get_stats = &pcnet32_get_stats;

    dev->set_multicast_list = &pcnet32_set_multicast_list;

    /* Fill in the generic fields of the device structure. */

    ether_setup(dev);

    return 0;

}

static int

pcnet32_open(struct device *dev)

{

        struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;

        unsigned int ioaddr = dev->base_addr;

        int i;

        if (dev->irq == 0 ||

                request_irq(dev->irq, &pcnet32_interrupt, SA_SHIRQ,

                                        dev->name, (void *)dev)) {

                return -EAGAIN;

        }

        MOD_INC_USE_COUNT;

        /* Reset the PCNET32 */

        inw(ioaddr+PCNET32_RESET);

        /* switch pcnet32 to 32bit mode */

        outw(0x0014, ioaddr+PCNET32_ADDR);

        outw(0x0002, ioaddr+PCNET32_BUS_IF);

        /* Turn on auto-select of media (AUI, BNC). */

        outw(0x0002, ioaddr+PCNET32_ADDR);

        /* only touch autoselect bit */

        outw(inw(ioaddr+PCNET32_BUS_IF) | 0x0002, ioaddr+PCNET32_BUS_IF);

        if (pcnet32_debug > 1)

                printk("%s: pcnet32_open() irq %d tx/rx rings %#x/%#x init %#x.\n",

                           dev->name, dev->irq,

                           (u32) virt_to_bus(lp->tx_ring),

                           (u32) virt_to_bus(lp->rx_ring),

                           (u32) virt_to_bus(&lp->init_block));

        /* check for ATLAS T1/E1 LAW card */

        if (dev->dev_addr[0] == 0x00 && dev->dev_addr[1] == 0xe0 && dev->dev_addr[2] == 0x75) {

                /* select GPSI mode */

                lp->init_block.mode = 0x0100;

                outw(0x0002, ioaddr+PCNET32_ADDR);

                outw(inw(ioaddr+PCNET32_BUS_IF) & ~2, ioaddr+PCNET32_BUS_IF);

                /* switch full duplex on */

                outw(0x0009, ioaddr+PCNET32_ADDR);

                outw(inw(ioaddr+PCNET32_BUS_IF) | 1, ioaddr+PCNET32_BUS_IF);

        } else

                lp->init_block.mode = 0x0000;

        lp->init_block.filter[0] = 0x00000000;

        lp->init_block.filter[1] = 0x00000000;

        pcnet32_init_ring(dev);

        /* Re-initialize the PCNET32, and start it when done. */

        outw(0x0001, ioaddr+PCNET32_ADDR);

        outw(virt_to_bus(&lp->init_block) &0xffff, ioaddr+PCNET32_DATA);

        outw(0x0002, ioaddr+PCNET32_ADDR);

        outw(virt_to_bus(&lp->init_block) >> 16, ioaddr+PCNET32_DATA);

        outw(0x0004, ioaddr+PCNET32_ADDR);

        outw(0x0915, ioaddr+PCNET32_DATA);

        outw(0x0000, ioaddr+PCNET32_ADDR);

        outw(0x0001, ioaddr+PCNET32_DATA);

        dev->tbusy = 0;

        dev->interrupt = 0;

        dev->start = 1;

        i = 0;

        while (i++ < 100)

                if (inw(ioaddr+PCNET32_DATA) & 0x0100)

                        break;

        /*

         * We used to clear the InitDone bit, 0x0100, here but Mark Stockton

         * reports that doing so triggers a bug in the '974.

         */

        outw(0x0042, ioaddr+PCNET32_DATA);

        if (pcnet32_debug > 2)

                printk("%s: PCNET32 open after %d ticks, init block %#x csr0 %4.4x.\n",

                           dev->name, i, (u32) virt_to_bus(&lp->init_block), inw(ioaddr+PCNET32_DATA));

        return 0;                                        /* Always succeed */

}

/*

 * The LANCE has been halted for one reason or another (busmaster memory

 * arbitration error, Tx FIFO underflow, driver stopped it to reconfigure,

 * etc.).  Modern LANCE variants always reload their ring-buffer

 * configuration when restarted, so we must reinitialize our ring

 * context before restarting.  As part of this reinitialization,

 * find all packets still on the Tx ring and pretend that they had been

 * sent (in effect, drop the packets on the floor) - the higher-level

 * protocols will time out and retransmit.  It'd be better to shuffle

 * these skbs to a temp list and then actually re-Tx them after

 * restarting the chip, but I'm too lazy to do so right now.  dplatt@3do.com

 */

static void

pcnet32_purge_tx_ring(struct device *dev)

{

        struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;

        int i;

        for (i = 0; i < TX_RING_SIZE; i++) {

                if (lp->tx_skbuff[i]) {

                        dev_kfree_skb(lp->tx_skbuff[i], FREE_WRITE);

                        lp->tx_skbuff[i] = NULL;

                }

        }

}

/* Initialize the PCNET32 Rx and Tx rings. */

static void

pcnet32_init_ring(struct device *dev)

{

        struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;

        int i;

        lp->lock = 0, lp->tx_full = 0;

        lp->cur_rx = lp->cur_tx = 0;

        lp->dirty_rx = lp->dirty_tx = 0;

        for (i = 0; i < RX_RING_SIZE; i++) {

                lp->rx_ring[i].base = (u32)le32_to_cpu(virt_to_bus((char *)lp->rx_buffs + i*PKT_BUF_SZ));

                lp->rx_ring[i].buf_length = le16_to_cpu(-PKT_BUF_SZ);

                lp->rx_ring[i].status = le16_to_cpu(0x8000);

        }

        /* The Tx buffer address is filled in as needed, but we do need to clear

           the upper ownership bit. */

        for (i = 0; i < TX_RING_SIZE; i++) {

                lp->tx_ring[i].base = 0;

                lp->tx_ring[i].status = 0;

        }

        lp->init_block.tlen_rlen = TX_RING_LEN_BITS | RX_RING_LEN_BITS;

        for (i = 0; i < 6; i++)

                lp->init_block.phys_addr[i] = dev->dev_addr[i];

        lp->init_block.rx_ring = (u32)le32_to_cpu(virt_to_bus(lp->rx_ring));

        lp->init_block.tx_ring = (u32)le32_to_cpu(virt_to_bus(lp->tx_ring));

}

static void

pcnet32_restart(struct device *dev, unsigned int csr0_bits, int must_reinit)

{

        int i;

        unsigned int ioaddr = dev->base_addr;

        pcnet32_purge_tx_ring(dev);

        pcnet32_init_ring(dev);

        outw(0x0000, ioaddr + PCNET32_ADDR);

        /* ReInit Ring */

        outw(0x0001, ioaddr + PCNET32_DATA);

        i = 0;

        while (i++ < 100)

                if (inw(ioaddr+PCNET32_DATA) & 0x0100)

                        break;

        outw(csr0_bits, ioaddr + PCNET32_DATA);

}

static int

pcnet32_start_xmit(struct sk_buff *skb, struct device *dev)

{

        struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;

        unsigned int ioaddr = dev->base_addr;

        int entry;

        unsigned long flags;

        /* Transmitter timeout, serious problems. */

        if (dev->tbusy) {

                int tickssofar = jiffies - dev->trans_start;

                if (tickssofar < 20)

                        return 1;

                outw(0, ioaddr+PCNET32_ADDR);

                printk("%s: transmit timed out, status %4.4x, resetting.\n",

                           dev->name, inw(ioaddr+PCNET32_DATA));

                outw(0x0004, ioaddr+PCNET32_DATA);

                lp->stats.tx_errors++;

#ifndef final_version

                {

                        int i;

                        printk(" Ring data dump: dirty_tx %d cur_tx %d%s cur_rx %d.",

                                   lp->dirty_tx, lp->cur_tx, lp->tx_full ? " (full)" : "",

                                   lp->cur_rx);

                        for (i = 0 ; i < RX_RING_SIZE; i++)

                                printk("%s %08x %04x %08x %04x", i & 1 ? "" : "\n ",

                                           lp->rx_ring[i].base, -lp->rx_ring[i].buf_length,

                                           lp->rx_ring[i].msg_length, (unsigned)lp->rx_ring[i].status);

                        for (i = 0 ; i < TX_RING_SIZE; i++)

                                printk("%s %08x %04x %08x %04x", i & 1 ? "" : "\n ",

                                           lp->tx_ring[i].base, -lp->tx_ring[i].length,

                                           lp->tx_ring[i].misc, (unsigned)lp->tx_ring[i].status);

                        printk("\n");

                }

#endif

                pcnet32_restart(dev, 0x0042, 1);

                dev->tbusy = 0;

                dev->trans_start = jiffies;

                return 0;

        }

        if (pcnet32_debug > 3) {

                outw(0x0000, ioaddr+PCNET32_ADDR);

                printk("%s: pcnet32_start_xmit() called, csr0 %4.4x.\n", dev->name,

                           inw(ioaddr+PCNET32_DATA));

                outw(0x0000, ioaddr+PCNET32_DATA);

        }

        /* Block a timer-based transmit from overlapping.  This could better be

           done with atomic_swap(1, dev->tbusy), but set_bit() works as well. */

        if (test_and_set_bit(0, (void*)&dev->tbusy) != 0) {

                printk("%s: Transmitter access conflict.\n", dev->name);

                return 1;

        }

        if (test_and_set_bit(0, (void*)&lp->lock) != 0) {

                if (pcnet32_debug > 0)

                        printk("%s: tx queue lock!.\n", dev->name);

                /* don't clear dev->tbusy flag. */

                return 1;

        }

        /* Fill in a Tx ring entry */

        /* Mask to ring buffer boundary. */

        entry = lp->cur_tx & TX_RING_MOD_MASK;

        /* Caution: the write order is important here, set the base address

           with the "ownership" bits last. */

        lp->tx_ring[entry].length = le16_to_cpu(-skb->len);

        lp->tx_ring[entry].misc = 0x00000000;

        lp->tx_skbuff[entry] = skb;

        lp->tx_ring[entry].base = (u32)le32_to_cpu(virt_to_bus(skb->data));

        lp->tx_ring[entry].status = le16_to_cpu(0x8300);

        lp->cur_tx++;

        /* Trigger an immediate send poll. */

        outw(0x0000, ioaddr+PCNET32_ADDR);

        outw(0x0048, ioaddr+PCNET32_DATA);

        dev->trans_start = jiffies;

        save_flags(flags);

        cli();

        lp->lock = 0;

        if (lp->tx_ring[(entry+1) & TX_RING_MOD_MASK].base == 0)

                clear_bit(0, (void*)&dev->tbusy);

        else

                lp->tx_full = 1;

        restore_flags(flags);

        return 0;

}

/* The PCNET32 interrupt handler. */

static void

pcnet32_interrupt(int irq, void *dev_id, struct pt_regs * regs)

{

        struct device *dev = (struct device *)dev_id;

        struct pcnet32_private *lp;

        unsigned int csr0, ioaddr;

        int boguscnt = max_interrupt_work;

        int must_restart;

        if (dev == NULL) {

                printk ("pcnet32_interrupt(): irq %d for unknown device.\n", irq);

                return;

        }

        ioaddr = dev->base_addr;

        lp = (struct pcnet32_private *)dev->priv;

        if (dev->interrupt)

                printk("%s: Re-entering the interrupt handler.\n", dev->name);

        dev->interrupt = 1;

        outw(0x00, dev->base_addr + PCNET32_ADDR);

        while ((csr0 = inw(dev->base_addr + PCNET32_DATA)) & 0x8600

                   && --boguscnt >= 0) {