net: add skb_dst_force() in sock_queue_err_skb()

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

/*
 *  Amiga Linux/m68k Ariadne Ethernet Driver
 *
 *  © Copyright 1995-2003 by Geert Uytterhoeven (geert@linux-m68k.org)
 *                           Peter De Schrijver (p2@mind.be)
 *
 *  ---------------------------------------------------------------------------
 *
 *  This program is based on
 *
 *      lance.c:        An AMD LANCE ethernet driver for linux.
 *                      Written 1993-94 by Donald Becker.
 *
 *      Am79C960:       PCnet(tm)-ISA Single-Chip Ethernet Controller
 *                      Advanced Micro Devices
 *                      Publication #16907, Rev. B, Amendment/0, May 1994
 *
 *      MC68230:        Parallel Interface/Timer (PI/T)
 *                      Motorola Semiconductors, December, 1983
 *
 *  ---------------------------------------------------------------------------
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License.  See the file COPYING in the main directory of the Linux
 *  distribution for more details.
 *
 *  ---------------------------------------------------------------------------
 *
 *  The Ariadne is a Zorro-II board made by Village Tronic. It contains:
 *
 *      - an Am79C960 PCnet-ISA Single-Chip Ethernet Controller with both
 *        10BASE-2 (thin coax) and 10BASE-T (UTP) connectors
 *
 *      - an MC68230 Parallel Interface/Timer configured as 2 parallel ports
 */

#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/interrupt.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/zorro.h>
#include <linux/bitops.h>

#include <asm/amigaints.h>
#include <asm/amigahw.h>
#include <asm/irq.h>

#include "ariadne.h"


#ifdef ARIADNE_DEBUG
int ariadne_debug = ARIADNE_DEBUG;
#else
int ariadne_debug = 1;
#endif


    /*
     *  Macros to Fix Endianness problems
     */

                                /* Swap the Bytes in a WORD */
#define swapw(x)        (((x>>8)&0x00ff)|((x<<8)&0xff00))
                                /* Get the Low BYTE in a WORD */
#define lowb(x)         (x&0xff)
                                /* Get the Swapped High WORD in a LONG */
#define swhighw(x)      ((((x)>>8)&0xff00)|(((x)>>24)&0x00ff))
                                /* Get the Swapped Low WORD in a LONG */
#define swloww(x)       ((((x)<<8)&0xff00)|(((x)>>8)&0x00ff))


    /*
     *  Transmit/Receive Ring Definitions
     */

#define TX_RING_SIZE    5
#define RX_RING_SIZE    16

#define PKT_BUF_SIZE    1520


    /*
     *  Private Device Data
     */

struct ariadne_private {
    volatile struct TDRE *tx_ring[TX_RING_SIZE];
    volatile struct RDRE *rx_ring[RX_RING_SIZE];
    volatile u_short *tx_buff[TX_RING_SIZE];
    volatile u_short *rx_buff[RX_RING_SIZE];
    int cur_tx, cur_rx;                 /* The next free ring entry */
    int dirty_tx;                       /* The ring entries to be free()ed. */
    char tx_full;
};


    /*
     *  Structure Created in the Ariadne's RAM Buffer
     */

struct lancedata {
    struct TDRE tx_ring[TX_RING_SIZE];
    struct RDRE rx_ring[RX_RING_SIZE];
    u_short tx_buff[TX_RING_SIZE][PKT_BUF_SIZE/sizeof(u_short)];
    u_short rx_buff[RX_RING_SIZE][PKT_BUF_SIZE/sizeof(u_short)];
};

static int ariadne_open(struct net_device *dev);
static void ariadne_init_ring(struct net_device *dev);
static netdev_tx_t ariadne_start_xmit(struct sk_buff *skb,
                                      struct net_device *dev);
static void ariadne_tx_timeout(struct net_device *dev);
static int ariadne_rx(struct net_device *dev);
static void ariadne_reset(struct net_device *dev);
static irqreturn_t ariadne_interrupt(int irq, void *data);
static int ariadne_close(struct net_device *dev);
static struct net_device_stats *ariadne_get_stats(struct net_device *dev);
static void set_multicast_list(struct net_device *dev);


static void memcpyw(volatile u_short *dest, u_short *src, int len)
{
    while (len >= 2) {
        *(dest++) = *(src++);
        len -= 2;
    }
    if (len == 1)
        *dest = (*(u_char *)src)<<8;
}


static int __devinit ariadne_init_one(struct zorro_dev *z,
                                      const struct zorro_device_id *ent);
static void __devexit ariadne_remove_one(struct zorro_dev *z);


static struct zorro_device_id ariadne_zorro_tbl[] __devinitdata = {
    { ZORRO_PROD_VILLAGE_TRONIC_ARIADNE },
    { 0 }
};
MODULE_DEVICE_TABLE(zorro, ariadne_zorro_tbl);

static struct zorro_driver ariadne_driver = {
    .name       = "ariadne",
    .id_table   = ariadne_zorro_tbl,
    .probe      = ariadne_init_one,
    .remove     = __devexit_p(ariadne_remove_one),
};

static const struct net_device_ops ariadne_netdev_ops = {
        .ndo_open               = ariadne_open,
        .ndo_stop               = ariadne_close,
        .ndo_start_xmit         = ariadne_start_xmit,
        .ndo_tx_timeout         = ariadne_tx_timeout,
        .ndo_get_stats          = ariadne_get_stats,
        .ndo_set_multicast_list = set_multicast_list,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_change_mtu         = eth_change_mtu,
        .ndo_set_mac_address    = eth_mac_addr,
};

static int __devinit ariadne_init_one(struct zorro_dev *z,
                                      const struct zorro_device_id *ent)
{
    unsigned long board = z->resource.start;
    unsigned long base_addr = board+ARIADNE_LANCE;
    unsigned long mem_start = board+ARIADNE_RAM;
    struct resource *r1, *r2;
    struct net_device *dev;
    struct ariadne_private *priv;
    int err;

    r1 = request_mem_region(base_addr, sizeof(struct Am79C960), "Am79C960");
    if (!r1)
        return -EBUSY;
    r2 = request_mem_region(mem_start, ARIADNE_RAM_SIZE, "RAM");
    if (!r2) {
        release_mem_region(base_addr, sizeof(struct Am79C960));
        return -EBUSY;
    }

    dev = alloc_etherdev(sizeof(struct ariadne_private));
    if (dev == NULL) {
        release_mem_region(base_addr, sizeof(struct Am79C960));
        release_mem_region(mem_start, ARIADNE_RAM_SIZE);
        return -ENOMEM;
    }

    priv = netdev_priv(dev);

    r1->name = dev->name;
    r2->name = dev->name;

    dev->dev_addr[0] = 0x00;
    dev->dev_addr[1] = 0x60;
    dev->dev_addr[2] = 0x30;
    dev->dev_addr[3] = (z->rom.er_SerialNumber>>16) & 0xff;
    dev->dev_addr[4] = (z->rom.er_SerialNumber>>8) & 0xff;
    dev->dev_addr[5] = z->rom.er_SerialNumber & 0xff;
    dev->base_addr = ZTWO_VADDR(base_addr);
    dev->mem_start = ZTWO_VADDR(mem_start);
    dev->mem_end = dev->mem_start+ARIADNE_RAM_SIZE;

    dev->netdev_ops = &ariadne_netdev_ops;
    dev->watchdog_timeo = 5*HZ;

    err = register_netdev(dev);
    if (err) {
        release_mem_region(base_addr, sizeof(struct Am79C960));
        release_mem_region(mem_start, ARIADNE_RAM_SIZE);
        free_netdev(dev);
        return err;
    }
    zorro_set_drvdata(z, dev);

    printk(KERN_INFO "%s: Ariadne at 0x%08lx, Ethernet Address %pM\n",
           dev->name, board, dev->dev_addr);

    return 0;
}


static int ariadne_open(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;
    u_short in;
    u_long version;
    int i;

    /* Reset the LANCE */
    in = lance->Reset;

    /* Stop the LANCE */
    lance->RAP = CSR0;          /* PCnet-ISA Controller Status */
    lance->RDP = STOP;

    /* Check the LANCE version */
    lance->RAP = CSR88;         /* Chip ID */
    version = swapw(lance->RDP);
    lance->RAP = CSR89;         /* Chip ID */
    version |= swapw(lance->RDP)<<16;
    if ((version & 0x00000fff) != 0x00000003) {
        printk(KERN_WARNING "ariadne_open: Couldn't find AMD Ethernet Chip\n");
        return -EAGAIN;
    }
    if ((version & 0x0ffff000) != 0x00003000) {
        printk(KERN_WARNING "ariadne_open: Couldn't find Am79C960 (Wrong part "
               "number = %ld)\n", (version & 0x0ffff000)>>12);
        return -EAGAIN;
    }
#if 0
    printk(KERN_DEBUG "ariadne_open: Am79C960 (PCnet-ISA) Revision %ld\n",
           (version & 0xf0000000)>>28);
#endif

    ariadne_init_ring(dev);

    /* Miscellaneous Stuff */
    lance->RAP = CSR3;          /* Interrupt Masks and Deferral Control */
    lance->RDP = 0x0000;
    lance->RAP = CSR4;          /* Test and Features Control */
    lance->RDP = DPOLL|APAD_XMT|MFCOM|RCVCCOM|TXSTRTM|JABM;

    /* Set the Multicast Table */
    lance->RAP = CSR8;          /* Logical Address Filter, LADRF[15:0] */
    lance->RDP = 0x0000;
    lance->RAP = CSR9;          /* Logical Address Filter, LADRF[31:16] */
    lance->RDP = 0x0000;
    lance->RAP = CSR10;         /* Logical Address Filter, LADRF[47:32] */
    lance->RDP = 0x0000;
    lance->RAP = CSR11;         /* Logical Address Filter, LADRF[63:48] */
    lance->RDP = 0x0000;

    /* Set the Ethernet Hardware Address */
    lance->RAP = CSR12;         /* Physical Address Register, PADR[15:0] */
    lance->RDP = ((u_short *)&dev->dev_addr[0])[0];
    lance->RAP = CSR13;         /* Physical Address Register, PADR[31:16] */
    lance->RDP = ((u_short *)&dev->dev_addr[0])[1];
    lance->RAP = CSR14;         /* Physical Address Register, PADR[47:32] */
    lance->RDP = ((u_short *)&dev->dev_addr[0])[2];

    /* Set the Init Block Mode */
    lance->RAP = CSR15;         /* Mode Register */
    lance->RDP = 0x0000;

    /* Set the Transmit Descriptor Ring Pointer */
    lance->RAP = CSR30;         /* Base Address of Transmit Ring */
    lance->RDP = swloww(ARIADNE_RAM+offsetof(struct lancedata, tx_ring));
    lance->RAP = CSR31;         /* Base Address of transmit Ring */
    lance->RDP = swhighw(ARIADNE_RAM+offsetof(struct lancedata, tx_ring));

    /* Set the Receive Descriptor Ring Pointer */
    lance->RAP = CSR24;         /* Base Address of Receive Ring */
    lance->RDP = swloww(ARIADNE_RAM+offsetof(struct lancedata, rx_ring));
    lance->RAP = CSR25;         /* Base Address of Receive Ring */
    lance->RDP = swhighw(ARIADNE_RAM+offsetof(struct lancedata, rx_ring));

    /* Set the Number of RX and TX Ring Entries */
    lance->RAP = CSR76;         /* Receive Ring Length */
    lance->RDP = swapw(((u_short)-RX_RING_SIZE));
    lance->RAP = CSR78;         /* Transmit Ring Length */
    lance->RDP = swapw(((u_short)-TX_RING_SIZE));

    /* Enable Media Interface Port Auto Select (10BASE-2/10BASE-T) */
    lance->RAP = ISACSR2;       /* Miscellaneous Configuration */
    lance->IDP = ASEL;

    /* LED Control */
    lance->RAP = ISACSR5;       /* LED1 Status */
    lance->IDP = PSE|XMTE;
    lance->RAP = ISACSR6;       /* LED2 Status */
    lance->IDP = PSE|COLE;
    lance->RAP = ISACSR7;       /* LED3 Status */
    lance->IDP = PSE|RCVE;

    netif_start_queue(dev);

    i = request_irq(IRQ_AMIGA_PORTS, ariadne_interrupt, IRQF_SHARED,
                    dev->name, dev);
    if (i) return i;

    lance->RAP = CSR0;          /* PCnet-ISA Controller Status */
    lance->RDP = INEA|STRT;

    return 0;
}


static void ariadne_init_ring(struct net_device *dev)
{
    struct ariadne_private *priv = netdev_priv(dev);
    volatile struct lancedata *lancedata = (struct lancedata *)dev->mem_start;
    int i;

    netif_stop_queue(dev);

    priv->tx_full = 0;
    priv->cur_rx = priv->cur_tx = 0;
    priv->dirty_tx = 0;

    /* Set up TX Ring */
    for (i = 0; i < TX_RING_SIZE; i++) {
        volatile struct TDRE *t = &lancedata->tx_ring[i];
        t->TMD0 = swloww(ARIADNE_RAM+offsetof(struct lancedata, tx_buff[i]));
        t->TMD1 = swhighw(ARIADNE_RAM+offsetof(struct lancedata, tx_buff[i])) |
                  TF_STP | TF_ENP;
        t->TMD2 = swapw((u_short)-PKT_BUF_SIZE);
        t->TMD3 = 0;
        priv->tx_ring[i] = &lancedata->tx_ring[i];
        priv->tx_buff[i] = lancedata->tx_buff[i];
#if 0
        printk(KERN_DEBUG "TX Entry %2d at %p, Buf at %p\n", i,
               &lancedata->tx_ring[i], lancedata->tx_buff[i]);
#endif
    }

    /* Set up RX Ring */
    for (i = 0; i < RX_RING_SIZE; i++) {
        volatile struct RDRE *r = &lancedata->rx_ring[i];
        r->RMD0 = swloww(ARIADNE_RAM+offsetof(struct lancedata, rx_buff[i]));
        r->RMD1 = swhighw(ARIADNE_RAM+offsetof(struct lancedata, rx_buff[i])) |
                  RF_OWN;
        r->RMD2 = swapw((u_short)-PKT_BUF_SIZE);
        r->RMD3 = 0x0000;
        priv->rx_ring[i] = &lancedata->rx_ring[i];
        priv->rx_buff[i] = lancedata->rx_buff[i];
#if 0
        printk(KERN_DEBUG "RX Entry %2d at %p, Buf at %p\n", i,
               &lancedata->rx_ring[i], lancedata->rx_buff[i]);
#endif
    }
}


static int ariadne_close(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;

    netif_stop_queue(dev);

    lance->RAP = CSR112;        /* Missed Frame Count */
    dev->stats.rx_missed_errors = swapw(lance->RDP);
    lance->RAP = CSR0;          /* PCnet-ISA Controller Status */

    if (ariadne_debug > 1) {
        printk(KERN_DEBUG "%s: Shutting down ethercard, status was %2.2x.\n",
               dev->name, lance->RDP);
        printk(KERN_DEBUG "%s: %lu packets missed\n", dev->name,
               dev->stats.rx_missed_errors);
    }

    /* We stop the LANCE here -- it occasionally polls memory if we don't. */
    lance->RDP = STOP;

    free_irq(IRQ_AMIGA_PORTS, dev);

    return 0;
}


static inline void ariadne_reset(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;

    lance->RAP = CSR0;  /* PCnet-ISA Controller Status */
    lance->RDP = STOP;
    ariadne_init_ring(dev);
    lance->RDP = INEA|STRT;
    netif_start_queue(dev);
}


static irqreturn_t ariadne_interrupt(int irq, void *data)
{
    struct net_device *dev = (struct net_device *)data;
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;
    struct ariadne_private *priv;
    int csr0, boguscnt;
    int handled = 0;

    lance->RAP = CSR0;                  /* PCnet-ISA Controller Status */

    if (!(lance->RDP & INTR))           /* Check if any interrupt has been */
        return IRQ_NONE;                /* generated by the board. */

    priv = netdev_priv(dev);

    boguscnt = 10;
    while ((csr0 = lance->RDP) & (ERR|RINT|TINT) && --boguscnt >= 0) {
        /* Acknowledge all of the current interrupt sources ASAP. */
        lance->RDP = csr0 & ~(INEA|TDMD|STOP|STRT|INIT);

#if 0
        if (ariadne_debug > 5) {
            printk(KERN_DEBUG "%s: interrupt  csr0=%#2.2x new csr=%#2.2x.",
                   dev->name, csr0, lance->RDP);
            printk("[");
            if (csr0 & INTR)
                printk(" INTR");
            if (csr0 & INEA)
                printk(" INEA");
            if (csr0 & RXON)
                printk(" RXON");
            if (csr0 & TXON)
                printk(" TXON");
            if (csr0 & TDMD)
                printk(" TDMD");
            if (csr0 & STOP)
                printk(" STOP");
            if (csr0 & STRT)
                printk(" STRT");
            if (csr0 & INIT)
                printk(" INIT");
            if (csr0 & ERR)
                printk(" ERR");
            if (csr0 & BABL)
                printk(" BABL");
            if (csr0 & CERR)
                printk(" CERR");
            if (csr0 & MISS)
                printk(" MISS");
            if (csr0 & MERR)
                printk(" MERR");
            if (csr0 & RINT)
                printk(" RINT");
            if (csr0 & TINT)
                printk(" TINT");
            if (csr0 & IDON)
                printk(" IDON");
            printk(" ]\n");
        }
#endif

        if (csr0 & RINT) {      /* Rx interrupt */
            handled = 1;
            ariadne_rx(dev);
        }

        if (csr0 & TINT) {      /* Tx-done interrupt */
            int dirty_tx = priv->dirty_tx;

            handled = 1;
            while (dirty_tx < priv->cur_tx) {
                int entry = dirty_tx % TX_RING_SIZE;
                int status = lowb(priv->tx_ring[entry]->TMD1);

                if (status & TF_OWN)
                    break;      /* It still hasn't been Txed */

                priv->tx_ring[entry]->TMD1 &= 0xff00;

                if (status & TF_ERR) {
                    /* There was an major error, log it. */
                    int err_status = priv->tx_ring[entry]->TMD3;
                    dev->stats.tx_errors++;
                    if (err_status & EF_RTRY)
                        dev->stats.tx_aborted_errors++;
                    if (err_status & EF_LCAR)
                        dev->stats.tx_carrier_errors++;
                    if (err_status & EF_LCOL)
                        dev->stats.tx_window_errors++;
                    if (err_status & EF_UFLO) {
                        /* Ackk!  On FIFO errors the Tx unit is turned off! */
                        dev->stats.tx_fifo_errors++;
                        /* Remove this verbosity later! */
                        printk(KERN_ERR "%s: Tx FIFO error! Status %4.4x.\n",
                               dev->name, csr0);
                        /* Restart the chip. */
                        lance->RDP = STRT;
                    }
                } else {
                    if (status & (TF_MORE|TF_ONE))
                        dev->stats.collisions++;
                    dev->stats.tx_packets++;
                }
                dirty_tx++;
            }

#ifndef final_version
            if (priv->cur_tx - dirty_tx >= TX_RING_SIZE) {
                printk(KERN_ERR "out-of-sync dirty pointer, %d vs. %d, "
                       "full=%d.\n", dirty_tx, priv->cur_tx, priv->tx_full);
                dirty_tx += TX_RING_SIZE;
            }
#endif

            if (priv->tx_full && netif_queue_stopped(dev) &&
                dirty_tx > priv->cur_tx - TX_RING_SIZE + 2) {
                /* The ring is no longer full. */
                priv->tx_full = 0;
                netif_wake_queue(dev);
            }

            priv->dirty_tx = dirty_tx;
        }

        /* Log misc errors. */
        if (csr0 & BABL) {
            handled = 1;
            dev->stats.tx_errors++;     /* Tx babble. */
        }
        if (csr0 & MISS) {
            handled = 1;
            dev->stats.rx_errors++;     /* Missed a Rx frame. */
        }
        if (csr0 & MERR) {
            handled = 1;
            printk(KERN_ERR "%s: Bus master arbitration failure, status "
                   "%4.4x.\n", dev->name, csr0);
            /* Restart the chip. */
            lance->RDP = STRT;
        }
    }

    /* Clear any other interrupt, and set interrupt enable. */
    lance->RAP = CSR0;          /* PCnet-ISA Controller Status */
    lance->RDP = INEA|BABL|CERR|MISS|MERR|IDON;

#if 0
    if (ariadne_debug > 4)
        printk(KERN_DEBUG "%s: exiting interrupt, csr%d=%#4.4x.\n", dev->name,
               lance->RAP, lance->RDP);
#endif
    return IRQ_RETVAL(handled);
}


static void ariadne_tx_timeout(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;

    printk(KERN_ERR "%s: transmit timed out, status %4.4x, resetting.\n",
           dev->name, lance->RDP);
    ariadne_reset(dev);
    netif_wake_queue(dev);
}


static netdev_tx_t ariadne_start_xmit(struct sk_buff *skb,
                                      struct net_device *dev)
{
    struct ariadne_private *priv = netdev_priv(dev);
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;
    int entry;
    unsigned long flags;
    int len = skb->len;

#if 0
    if (ariadne_debug > 3) {
        lance->RAP = CSR0;      /* PCnet-ISA Controller Status */
        printk(KERN_DEBUG "%s: ariadne_start_xmit() called, csr0 %4.4x.\n",
               dev->name, lance->RDP);
        lance->RDP = 0x0000;
    }
#endif

    /* FIXME: is the 79C960 new enough to do its own padding right ? */
    if (skb->len < ETH_ZLEN)
    {
        if (skb_padto(skb, ETH_ZLEN))
            return NETDEV_TX_OK;
        len = ETH_ZLEN;
    }

    /* Fill in a Tx ring entry */

#if 0
{
    printk(KERN_DEBUG "TX pkt type 0x%04x from %pM to %pM "
           " data 0x%08x len %d\n",
           ((u_short *)skb->data)[6],
           skb->data + 6, skb->data,
           (int)skb->data, (int)skb->len);
}
#endif

    local_irq_save(flags);

    entry = priv->cur_tx % TX_RING_SIZE;

    /* Caution: the write order is important here, set the base address with
                the "ownership" bits last. */

    priv->tx_ring[entry]->TMD2 = swapw((u_short)-skb->len);
    priv->tx_ring[entry]->TMD3 = 0x0000;
    memcpyw(priv->tx_buff[entry], (u_short *)skb->data, len);

#if 0
    {
        int i, len;

        len = skb->len > 64 ? 64 : skb->len;
        len >>= 1;
        for (i = 0; i < len; i += 8) {
            int j;
            printk(KERN_DEBUG "%04x:", i);
            for (j = 0; (j < 8) && ((i+j) < len); j++) {
                if (!(j & 1))
                    printk(" ");
                printk("%04x", priv->tx_buff[entry][i+j]);
            }
            printk("\n");
        }
    }
#endif

    priv->tx_ring[entry]->TMD1 = (priv->tx_ring[entry]->TMD1&0xff00)|TF_OWN|TF_STP|TF_ENP;

    dev_kfree_skb(skb);

    priv->cur_tx++;
    if ((priv->cur_tx >= TX_RING_SIZE) && (priv->dirty_tx >= TX_RING_SIZE)) {

#if 0
        printk(KERN_DEBUG "*** Subtracting TX_RING_SIZE from cur_tx (%d) and "
               "dirty_tx (%d)\n", priv->cur_tx, priv->dirty_tx);
#endif

        priv->cur_tx -= TX_RING_SIZE;
        priv->dirty_tx -= TX_RING_SIZE;
    }
    dev->stats.tx_bytes += len;

    /* Trigger an immediate send poll. */
    lance->RAP = CSR0;          /* PCnet-ISA Controller Status */
    lance->RDP = INEA|TDMD;

    if (lowb(priv->tx_ring[(entry+1) % TX_RING_SIZE]->TMD1) != 0) {
        netif_stop_queue(dev);
        priv->tx_full = 1;
    }
    local_irq_restore(flags);

    return NETDEV_TX_OK;
}


static int ariadne_rx(struct net_device *dev)
{
    struct ariadne_private *priv = netdev_priv(dev);
    int entry = priv->cur_rx % RX_RING_SIZE;
    int i;

    /* If we own the next entry, it's a new packet. Send it up. */
    while (!(lowb(priv->rx_ring[entry]->RMD1) & RF_OWN)) {
        int status = lowb(priv->rx_ring[entry]->RMD1);

        if (status != (RF_STP|RF_ENP)) {        /* There was an error. */
            /* There is a tricky error noted by John Murphy,
                <murf@perftech.com> to Russ Nelson: Even with full-sized
                buffers it's possible for a jabber packet to use two
                buffers, with only the last correctly noting the error. */
            if (status & RF_ENP)
                /* Only count a general error at the end of a packet.*/
                dev->stats.rx_errors++;
            if (status & RF_FRAM)
                dev->stats.rx_frame_errors++;
            if (status & RF_OFLO)
                dev->stats.rx_over_errors++;
            if (status & RF_CRC)
                dev->stats.rx_crc_errors++;
            if (status & RF_BUFF)
                dev->stats.rx_fifo_errors++;
            priv->rx_ring[entry]->RMD1 &= 0xff00|RF_STP|RF_ENP;
        } else {
            /* Malloc up new buffer, compatible with net-3. */
            short pkt_len = swapw(priv->rx_ring[entry]->RMD3);
            struct sk_buff *skb;

            skb = dev_alloc_skb(pkt_len+2);
            if (skb == NULL) {
                printk(KERN_WARNING "%s: Memory squeeze, deferring packet.\n",
                       dev->name);
                for (i = 0; i < RX_RING_SIZE; i++)
                    if (lowb(priv->rx_ring[(entry+i) % RX_RING_SIZE]->RMD1) & RF_OWN)
                        break;

                if (i > RX_RING_SIZE-2) {
                    dev->stats.rx_dropped++;
                    priv->rx_ring[entry]->RMD1 |= RF_OWN;
                    priv->cur_rx++;
                }
                break;
            }


            skb_reserve(skb,2);         /* 16 byte align */
            skb_put(skb,pkt_len);       /* Make room */
            skb_copy_to_linear_data(skb, (char *)priv->rx_buff[entry], pkt_len);
            skb->protocol=eth_type_trans(skb,dev);
#if 0
{
            printk(KERN_DEBUG "RX pkt type 0x%04x from ",
                   ((u_short *)skb->data)[6]);
            {
                u_char *ptr = &((u_char *)skb->data)[6];
                printk("%pM", ptr);
            }
            printk(" to ");
            {
                u_char *ptr = (u_char *)skb->data;
                printk("%pM", ptr);
            }
            printk(" data 0x%08x len %d\n", (int)skb->data, (int)skb->len);
}
#endif

            netif_rx(skb);
            dev->stats.rx_packets++;
            dev->stats.rx_bytes += pkt_len;
        }

        priv->rx_ring[entry]->RMD1 |= RF_OWN;
        entry = (++priv->cur_rx) % RX_RING_SIZE;
    }

    priv->cur_rx = priv->cur_rx % RX_RING_SIZE;

    /* We should check that at least two ring entries are free.  If not,
       we should free one and mark stats->rx_dropped++. */

    return 0;
}


static struct net_device_stats *ariadne_get_stats(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;
    short saved_addr;
    unsigned long flags;

    local_irq_save(flags);
    saved_addr = lance->RAP;
    lance->RAP = CSR112;                /* Missed Frame Count */
    dev->stats.rx_missed_errors = swapw(lance->RDP);
    lance->RAP = saved_addr;
    local_irq_restore(flags);

    return &dev->stats;
}


/* Set or clear the multicast filter for this adaptor.
    num_addrs == -1     Promiscuous mode, receive all packets
    num_addrs == 0      Normal mode, clear multicast list
    num_addrs > 0       Multicast mode, receive normal and MC packets, and do
                        best-effort filtering.
 */
static void set_multicast_list(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;

    if (!netif_running(dev))
        return;

    netif_stop_queue(dev);

    /* We take the simple way out and always enable promiscuous mode. */
    lance->RAP = CSR0;                  /* PCnet-ISA Controller Status */
    lance->RDP = STOP;                  /* Temporarily stop the lance. */
    ariadne_init_ring(dev);

    if (dev->flags & IFF_PROMISC) {
        lance->RAP = CSR15;             /* Mode Register */
        lance->RDP = PROM;              /* Set promiscuous mode */
    } else {
        short multicast_table[4];
        int num_addrs = netdev_mc_count(dev);
        int i;
        /* We don't use the multicast table, but rely on upper-layer filtering. */
        memset(multicast_table, (num_addrs == 0) ? 0 : -1,
               sizeof(multicast_table));
        for (i = 0; i < 4; i++) {
            lance->RAP = CSR8+(i<<8);   /* Logical Address Filter */
            lance->RDP = swapw(multicast_table[i]);
        }
        lance->RAP = CSR15;             /* Mode Register */
        lance->RDP = 0x0000;            /* Unset promiscuous mode */
    }

    lance->RAP = CSR0;                  /* PCnet-ISA Controller Status */
    lance->RDP = INEA|STRT|IDON;        /* Resume normal operation. */

    netif_wake_queue(dev);
}


static void __devexit ariadne_remove_one(struct zorro_dev *z)
{
    struct net_device *dev = zorro_get_drvdata(z);

    unregister_netdev(dev);
    release_mem_region(ZTWO_PADDR(dev->base_addr), sizeof(struct Am79C960));
    release_mem_region(ZTWO_PADDR(dev->mem_start), ARIADNE_RAM_SIZE);
    free_netdev(dev);
}

static int __init ariadne_init_module(void)
{
    return zorro_register_driver(&ariadne_driver);
}

static void __exit ariadne_cleanup_module(void)
{
    zorro_unregister_driver(&ariadne_driver);
}

module_init(ariadne_init_module);
module_exit(ariadne_cleanup_module);

MODULE_LICENSE("GPL");