spider_net.c

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/*
 * Network device driver for Cell Processor-Based Blade and Celleb platform
 *
 * (C) Copyright IBM Corp. 2005
 * (C) Copyright 2006 TOSHIBA CORPORATION
 *
 * Authors : Utz Bacher <[email protected]>
 *           Jens Osterkamp <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/compiler.h>
#include <linux/crc32.h>
#include <linux/delay.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/firmware.h>
#include <linux/if_vlan.h>
#include <linux/in.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/gfp.h>
#include <linux/ioport.h>
#include <linux/ip.h>
#include <linux/kernel.h>
#include <linux/mii.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/device.h>
#include <linux/pci.h>
#include <linux/skbuff.h>
#include <linux/tcp.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/bitops.h>
#include <asm/pci-bridge.h>
#include <net/checksum.h>

#include "spider_net.h"

MODULE_AUTHOR("Utz Bacher <[email protected]> and Jens Osterkamp " \
          "<[email protected]>");
MODULE_DESCRIPTION("Spider Southbridge Gigabit Ethernet driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(VERSION);
MODULE_FIRMWARE(SPIDER_NET_FIRMWARE_NAME);

static int rx_descriptors = SPIDER_NET_RX_DESCRIPTORS_DEFAULT;
static int tx_descriptors = SPIDER_NET_TX_DESCRIPTORS_DEFAULT;

module_param(rx_descriptors, int, 0444);
module_param(tx_descriptors, int, 0444);

MODULE_PARM_DESC(rx_descriptors, "number of descriptors used " \
         "in rx chains");
MODULE_PARM_DESC(tx_descriptors, "number of descriptors used " \
         "in tx chain");

char spider_net_driver_name[] = "spidernet";

static DEFINE_PCI_DEVICE_TABLE(spider_net_pci_tbl) = {
    { PCI_VENDOR_ID_TOSHIBA_2, PCI_DEVICE_ID_TOSHIBA_SPIDER_NET,
      PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0UL },
    { 0, }
};

MODULE_DEVICE_TABLE(pci, spider_net_pci_tbl);

static inline u32
spider_net_read_reg(struct spider_net_card *card, u32 reg)
{
    /* We use the powerpc specific variants instead of readl_be() because
     * we know spidernet is not a real PCI device and we can thus avoid the
     * performance hit caused by the PCI workarounds.
     */
    return in_be32(card->regs + reg);
}

static inline void
spider_net_write_reg(struct spider_net_card *card, u32 reg, u32 value)
{
    /* We use the powerpc specific variants instead of writel_be() because
     * we know spidernet is not a real PCI device and we can thus avoid the
     * performance hit caused by the PCI workarounds.
     */
    out_be32(card->regs + reg, value);
}

static void
spider_net_write_phy(struct net_device *netdev, int mii_id,
             int reg, int val)
{
    struct spider_net_card *card = netdev_priv(netdev);
    u32 writevalue;

    writevalue = ((u32)mii_id << 21) |
        ((u32)reg << 16) | ((u32)val);

    spider_net_write_reg(card, SPIDER_NET_GPCWOPCMD, writevalue);
}

static int
spider_net_read_phy(struct net_device *netdev, int mii_id, int reg)
{
    struct spider_net_card *card = netdev_priv(netdev);
    u32 readvalue;

    readvalue = ((u32)mii_id << 21) | ((u32)reg << 16);
    spider_net_write_reg(card, SPIDER_NET_GPCROPCMD, readvalue);

    /* we don't use semaphores to wait for an SPIDER_NET_GPROPCMPINT
     * interrupt, as we poll for the completion of the read operation
     * in spider_net_read_phy. Should take about 50 us */
    do {
        readvalue = spider_net_read_reg(card, SPIDER_NET_GPCROPCMD);
    } while (readvalue & SPIDER_NET_GPREXEC);

    readvalue &= SPIDER_NET_GPRDAT_MASK;

    return readvalue;
}

static void
spider_net_setup_aneg(struct spider_net_card *card)
{
    struct mii_phy *phy = &card->phy;
    u32 advertise = 0;
    u16 bmsr, estat;

    bmsr  = spider_net_read_phy(card->netdev, phy->mii_id, MII_BMSR);
    estat = spider_net_read_phy(card->netdev, phy->mii_id, MII_ESTATUS);

    if (bmsr & BMSR_10HALF)
        advertise |= ADVERTISED_10baseT_Half;
    if (bmsr & BMSR_10FULL)
        advertise |= ADVERTISED_10baseT_Full;
    if (bmsr & BMSR_100HALF)
        advertise |= ADVERTISED_100baseT_Half;
    if (bmsr & BMSR_100FULL)
        advertise |= ADVERTISED_100baseT_Full;

    if ((bmsr & BMSR_ESTATEN) && (estat & ESTATUS_1000_TFULL))
        advertise |= SUPPORTED_1000baseT_Full;
    if ((bmsr & BMSR_ESTATEN) && (estat & ESTATUS_1000_THALF))
        advertise |= SUPPORTED_1000baseT_Half;

    sungem_phy_probe(phy, phy->mii_id);
    phy->def->ops->setup_aneg(phy, advertise);

}

static void
spider_net_rx_irq_off(struct spider_net_card *card)
{
    u32 regvalue;

    regvalue = SPIDER_NET_INT0_MASK_VALUE & (~SPIDER_NET_RXINT);
    spider_net_write_reg(card, SPIDER_NET_GHIINT0MSK, regvalue);
}

static void
spider_net_rx_irq_on(struct spider_net_card *card)
{
    u32 regvalue;

    regvalue = SPIDER_NET_INT0_MASK_VALUE | SPIDER_NET_RXINT;
    spider_net_write_reg(card, SPIDER_NET_GHIINT0MSK, regvalue);
}

static void
spider_net_set_promisc(struct spider_net_card *card)
{
    u32 macu, macl;
    struct net_device *netdev = card->netdev;

    if (netdev->flags & IFF_PROMISC) {
        /* clear destination entry 0 */
        spider_net_write_reg(card, SPIDER_NET_GMRUAFILnR, 0);
        spider_net_write_reg(card, SPIDER_NET_GMRUAFILnR + 0x04, 0);
        spider_net_write_reg(card, SPIDER_NET_GMRUA0FIL15R,
                     SPIDER_NET_PROMISC_VALUE);
    } else {
        macu = netdev->dev_addr[0];
        macu <<= 8;
        macu |= netdev->dev_addr[1];
        memcpy(&macl, &netdev->dev_addr[2], sizeof(macl));

        macu |= SPIDER_NET_UA_DESCR_VALUE;
        spider_net_write_reg(card, SPIDER_NET_GMRUAFILnR, macu);
        spider_net_write_reg(card, SPIDER_NET_GMRUAFILnR + 0x04, macl);
        spider_net_write_reg(card, SPIDER_NET_GMRUA0FIL15R,
                     SPIDER_NET_NONPROMISC_VALUE);
    }
}

static int
spider_net_get_mac_address(struct net_device *netdev)
{
    struct spider_net_card *card = netdev_priv(netdev);
    u32 macl, macu;

    macl = spider_net_read_reg(card, SPIDER_NET_GMACUNIMACL);
    macu = spider_net_read_reg(card, SPIDER_NET_GMACUNIMACU);

    netdev->dev_addr[0] = (macu >> 24) & 0xff;
    netdev->dev_addr[1] = (macu >> 16) & 0xff;
    netdev->dev_addr[2] = (macu >> 8) & 0xff;
    netdev->dev_addr[3] = macu & 0xff;
    netdev->dev_addr[4] = (macl >> 8) & 0xff;
    netdev->dev_addr[5] = macl & 0xff;

    if (!is_valid_ether_addr(&netdev->dev_addr[0]))
        return -EINVAL;

    return 0;
}

static inline int
spider_net_get_descr_status(struct spider_net_hw_descr *hwdescr)
{
    return hwdescr->dmac_cmd_status & SPIDER_NET_DESCR_IND_PROC_MASK;
}

static void
spider_net_free_chain(struct spider_net_card *card,
              struct spider_net_descr_chain *chain)
{
    struct spider_net_descr *descr;

    descr = chain->ring;
    do {
        descr->bus_addr = 0;
        descr->hwdescr->next_descr_addr = 0;
        descr = descr->next;
    } while (descr != chain->ring);

    dma_free_coherent(&card->pdev->dev, chain->num_desc,
        chain->hwring, chain->dma_addr);
}

static int
spider_net_init_chain(struct spider_net_card *card,
               struct spider_net_descr_chain *chain)
{
    int i;
    struct spider_net_descr *descr;
    struct spider_net_hw_descr *hwdescr;
    dma_addr_t buf;
    size_t alloc_size;

    alloc_size = chain->num_desc * sizeof(struct spider_net_hw_descr);

    chain->hwring = dma_alloc_coherent(&card->pdev->dev, alloc_size,
        &chain->dma_addr, GFP_KERNEL);

    if (!chain->hwring)
        return -ENOMEM;

    memset(chain->ring, 0, chain->num_desc * sizeof(struct spider_net_descr));

    /* Set up the hardware pointers in each descriptor */
    descr = chain->ring;
    hwdescr = chain->hwring;
    buf = chain->dma_addr;
    for (i=0; i < chain->num_desc; i++, descr++, hwdescr++) {
        hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
        hwdescr->next_descr_addr = 0;

        descr->hwdescr = hwdescr;
        descr->bus_addr = buf;
        descr->next = descr + 1;
        descr->prev = descr - 1;

        buf += sizeof(struct spider_net_hw_descr);
    }
    /* do actual circular list */
    (descr-1)->next = chain->ring;
    chain->ring->prev = descr-1;

    spin_lock_init(&chain->lock);
    chain->head = chain->ring;
    chain->tail = chain->ring;
    return 0;
}

static void
spider_net_free_rx_chain_contents(struct spider_net_card *card)
{
    struct spider_net_descr *descr;

    descr = card->rx_chain.head;
    do {
        if (descr->skb) {
            pci_unmap_single(card->pdev, descr->hwdescr->buf_addr,
                     SPIDER_NET_MAX_FRAME,
                     PCI_DMA_BIDIRECTIONAL);
            dev_kfree_skb(descr->skb);
            descr->skb = NULL;
        }
        descr = descr->next;
    } while (descr != card->rx_chain.head);
}

static int
spider_net_prepare_rx_descr(struct spider_net_card *card,
                struct spider_net_descr *descr)
{
    struct spider_net_hw_descr *hwdescr = descr->hwdescr;
    dma_addr_t buf;
    int offset;
    int bufsize;

    /* we need to round up the buffer size to a multiple of 128 */
    bufsize = (SPIDER_NET_MAX_FRAME + SPIDER_NET_RXBUF_ALIGN - 1) &
        (~(SPIDER_NET_RXBUF_ALIGN - 1));

    /* and we need to have it 128 byte aligned, therefore we allocate a
     * bit more */
    /* allocate an skb */
    descr->skb = netdev_alloc_skb(card->netdev,
                      bufsize + SPIDER_NET_RXBUF_ALIGN - 1);
    if (!descr->skb) {
        if (netif_msg_rx_err(card) && net_ratelimit())
            dev_err(&card->netdev->dev,
                    "Not enough memory to allocate rx buffer\n");
        card->spider_stats.alloc_rx_skb_error++;
        return -ENOMEM;
    }
    hwdescr->buf_size = bufsize;
    hwdescr->result_size = 0;
    hwdescr->valid_size = 0;
    hwdescr->data_status = 0;
    hwdescr->data_error = 0;

    offset = ((unsigned long)descr->skb->data) &
        (SPIDER_NET_RXBUF_ALIGN - 1);
    if (offset)
        skb_reserve(descr->skb, SPIDER_NET_RXBUF_ALIGN - offset);
    /* iommu-map the skb */
    buf = pci_map_single(card->pdev, descr->skb->data,
            SPIDER_NET_MAX_FRAME, PCI_DMA_FROMDEVICE);
    if (pci_dma_mapping_error(card->pdev, buf)) {
        dev_kfree_skb_any(descr->skb);
        descr->skb = NULL;
        if (netif_msg_rx_err(card) && net_ratelimit())
            dev_err(&card->netdev->dev, "Could not iommu-map rx buffer\n");
        card->spider_stats.rx_iommu_map_error++;
        hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
    } else {
        hwdescr->buf_addr = buf;
        wmb();
        hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_CARDOWNED |
                     SPIDER_NET_DMAC_NOINTR_COMPLETE;
    }

    return 0;
}

static inline void
spider_net_enable_rxchtails(struct spider_net_card *card)
{
    /* assume chain is aligned correctly */
    spider_net_write_reg(card, SPIDER_NET_GDADCHA ,
                 card->rx_chain.tail->bus_addr);
}

static inline void
spider_net_enable_rxdmac(struct spider_net_card *card)
{
    wmb();
    spider_net_write_reg(card, SPIDER_NET_GDADMACCNTR,
                 SPIDER_NET_DMA_RX_VALUE);
}

static inline void
spider_net_disable_rxdmac(struct spider_net_card *card)
{
    spider_net_write_reg(card, SPIDER_NET_GDADMACCNTR,
                 SPIDER_NET_DMA_RX_FEND_VALUE);
}

static void
spider_net_refill_rx_chain(struct spider_net_card *card)
{
    struct spider_net_descr_chain *chain = &card->rx_chain;
    unsigned long flags;

    /* one context doing the refill (and a second context seeing that
     * and omitting it) is ok. If called by NAPI, we'll be called again
     * as spider_net_decode_one_descr is called several times. If some
     * interrupt calls us, the NAPI is about to clean up anyway. */
    if (!spin_trylock_irqsave(&chain->lock, flags))
        return;

    while (spider_net_get_descr_status(chain->head->hwdescr) ==
            SPIDER_NET_DESCR_NOT_IN_USE) {
        if (spider_net_prepare_rx_descr(card, chain->head))
            break;
        chain->head = chain->head->next;
    }

    spin_unlock_irqrestore(&chain->lock, flags);
}

static int
spider_net_alloc_rx_skbs(struct spider_net_card *card)
{
    struct spider_net_descr_chain *chain = &card->rx_chain;
    struct spider_net_descr *start = chain->tail;
    struct spider_net_descr *descr = start;

    /* Link up the hardware chain pointers */
    do {
        descr->prev->hwdescr->next_descr_addr = descr->bus_addr;
        descr = descr->next;
    } while (descr != start);

    /* Put at least one buffer into the chain. if this fails,
     * we've got a problem. If not, spider_net_refill_rx_chain
     * will do the rest at the end of this function. */
    if (spider_net_prepare_rx_descr(card, chain->head))
        goto error;
    else
        chain->head = chain->head->next;

    /* This will allocate the rest of the rx buffers;
     * if not, it's business as usual later on. */
    spider_net_refill_rx_chain(card);
    spider_net_enable_rxdmac(card);
    return 0;

error:
    spider_net_free_rx_chain_contents(card);
    return -ENOMEM;
}

static u8
spider_net_get_multicast_hash(struct net_device *netdev, __u8 *addr)
{
    u32 crc;
    u8 hash;
    char addr_for_crc[ETH_ALEN] = { 0, };
    int i, bit;

    for (i = 0; i < ETH_ALEN * 8; i++) {
        bit = (addr[i / 8] >> (i % 8)) & 1;
        addr_for_crc[ETH_ALEN - 1 - i / 8] += bit << (7 - (i % 8));
    }

    crc = crc32_be(~0, addr_for_crc, netdev->addr_len);

    hash = (crc >> 27);
    hash <<= 3;
    hash |= crc & 7;
    hash &= 0xff;

    return hash;
}

static void
spider_net_set_multi(struct net_device *netdev)
{
    struct netdev_hw_addr *ha;
    u8 hash;
    int i;
    u32 reg;
    struct spider_net_card *card = netdev_priv(netdev);
    unsigned long bitmask[SPIDER_NET_MULTICAST_HASHES / BITS_PER_LONG] =
        {0, };

    spider_net_set_promisc(card);

    if (netdev->flags & IFF_ALLMULTI) {
        for (i = 0; i < SPIDER_NET_MULTICAST_HASHES; i++) {
            set_bit(i, bitmask);
        }
        goto write_hash;
    }

    /* well, we know, what the broadcast hash value is: it's xfd
    hash = spider_net_get_multicast_hash(netdev, netdev->broadcast); */
    set_bit(0xfd, bitmask);

    netdev_for_each_mc_addr(ha, netdev) {
        hash = spider_net_get_multicast_hash(netdev, ha->addr);
        set_bit(hash, bitmask);
    }

write_hash:
    for (i = 0; i < SPIDER_NET_MULTICAST_HASHES / 4; i++) {
        reg = 0;
        if (test_bit(i * 4, bitmask))
            reg += 0x08;
        reg <<= 8;
        if (test_bit(i * 4 + 1, bitmask))
            reg += 0x08;
        reg <<= 8;
        if (test_bit(i * 4 + 2, bitmask))
            reg += 0x08;
        reg <<= 8;
        if (test_bit(i * 4 + 3, bitmask))
            reg += 0x08;

        spider_net_write_reg(card, SPIDER_NET_GMRMHFILnR + i * 4, reg);
    }
}

static int
spider_net_prepare_tx_descr(struct spider_net_card *card,
                struct sk_buff *skb)
{
    struct spider_net_descr_chain *chain = &card->tx_chain;
    struct spider_net_descr *descr;
    struct spider_net_hw_descr *hwdescr;
    dma_addr_t buf;
    unsigned long flags;

    buf = pci_map_single(card->pdev, skb->data, skb->len, PCI_DMA_TODEVICE);
    if (pci_dma_mapping_error(card->pdev, buf)) {
        if (netif_msg_tx_err(card) && net_ratelimit())
            dev_err(&card->netdev->dev, "could not iommu-map packet (%p, %i). "
                  "Dropping packet\n", skb->data, skb->len);
        card->spider_stats.tx_iommu_map_error++;
        return -ENOMEM;
    }

    spin_lock_irqsave(&chain->lock, flags);
    descr = card->tx_chain.head;
    if (descr->next == chain->tail->prev) {
        spin_unlock_irqrestore(&chain->lock, flags);
        pci_unmap_single(card->pdev, buf, skb->len, PCI_DMA_TODEVICE);
        return -ENOMEM;
    }
    hwdescr = descr->hwdescr;
    chain->head = descr->next;

    descr->skb = skb;
    hwdescr->buf_addr = buf;
    hwdescr->buf_size = skb->len;
    hwdescr->next_descr_addr = 0;
    hwdescr->data_status = 0;

    hwdescr->dmac_cmd_status =
            SPIDER_NET_DESCR_CARDOWNED | SPIDER_NET_DMAC_TXFRMTL;
    spin_unlock_irqrestore(&chain->lock, flags);

    if (skb->ip_summed == CHECKSUM_PARTIAL)
        switch (ip_hdr(skb)->protocol) {
        case IPPROTO_TCP:
            hwdescr->dmac_cmd_status |= SPIDER_NET_DMAC_TCP;
            break;
        case IPPROTO_UDP:
            hwdescr->dmac_cmd_status |= SPIDER_NET_DMAC_UDP;
            break;
        }

    /* Chain the bus address, so that the DMA engine finds this descr. */
    wmb();
    descr->prev->hwdescr->next_descr_addr = descr->bus_addr;

    card->netdev->trans_start = jiffies; /* set netdev watchdog timer */
    return 0;
}

static int
spider_net_set_low_watermark(struct spider_net_card *card)
{
    struct spider_net_descr *descr = card->tx_chain.tail;
    struct spider_net_hw_descr *hwdescr;
    unsigned long flags;
    int status;
    int cnt=0;
    int i;

    /* Measure the length of the queue. Measurement does not
     * need to be precise -- does not need a lock. */
    while (descr != card->tx_chain.head) {
        status = descr->hwdescr->dmac_cmd_status & SPIDER_NET_DESCR_NOT_IN_USE;
        if (status == SPIDER_NET_DESCR_NOT_IN_USE)
            break;
        descr = descr->next;
        cnt++;
    }

    /* If TX queue is short, don't even bother with interrupts */
    if (cnt < card->tx_chain.num_desc/4)
        return cnt;

    /* Set low-watermark 3/4th's of the way into the queue. */
    descr = card->tx_chain.tail;
    cnt = (cnt*3)/4;
    for (i=0;i<cnt; i++)
        descr = descr->next;

    /* Set the new watermark, clear the old watermark */
    spin_lock_irqsave(&card->tx_chain.lock, flags);
    descr->hwdescr->dmac_cmd_status |= SPIDER_NET_DESCR_TXDESFLG;
    if (card->low_watermark && card->low_watermark != descr) {
        hwdescr = card->low_watermark->hwdescr;
        hwdescr->dmac_cmd_status =
             hwdescr->dmac_cmd_status & ~SPIDER_NET_DESCR_TXDESFLG;
    }
    card->low_watermark = descr;
    spin_unlock_irqrestore(&card->tx_chain.lock, flags);
    return cnt;
}

static int
spider_net_release_tx_chain(struct spider_net_card *card, int brutal)
{
    struct net_device *dev = card->netdev;
    struct spider_net_descr_chain *chain = &card->tx_chain;
    struct spider_net_descr *descr;
    struct spider_net_hw_descr *hwdescr;
    struct sk_buff *skb;
    u32 buf_addr;
    unsigned long flags;
    int status;

    while (1) {
        spin_lock_irqsave(&chain->lock, flags);
        if (chain->tail == chain->head) {
            spin_unlock_irqrestore(&chain->lock, flags);
            return 0;
        }
        descr = chain->tail;
        hwdescr = descr->hwdescr;

        status = spider_net_get_descr_status(hwdescr);
        switch (status) {
        case SPIDER_NET_DESCR_COMPLETE:
            dev->stats.tx_packets++;
            dev->stats.tx_bytes += descr->skb->len;
            break;

        case SPIDER_NET_DESCR_CARDOWNED:
            if (!brutal) {
                spin_unlock_irqrestore(&chain->lock, flags);
                return 1;
            }

            /* fallthrough, if we release the descriptors
             * brutally (then we don't care about
             * SPIDER_NET_DESCR_CARDOWNED) */

        case SPIDER_NET_DESCR_RESPONSE_ERROR:
        case SPIDER_NET_DESCR_PROTECTION_ERROR:
        case SPIDER_NET_DESCR_FORCE_END:
            if (netif_msg_tx_err(card))
                dev_err(&card->netdev->dev, "forcing end of tx descriptor "
                       "with status x%02x\n", status);
            dev->stats.tx_errors++;
            break;

        default:
            dev->stats.tx_dropped++;
            if (!brutal) {
                spin_unlock_irqrestore(&chain->lock, flags);
                return 1;
            }
        }

        chain->tail = descr->next;
        hwdescr->dmac_cmd_status |= SPIDER_NET_DESCR_NOT_IN_USE;
        skb = descr->skb;
        descr->skb = NULL;
        buf_addr = hwdescr->buf_addr;
        spin_unlock_irqrestore(&chain->lock, flags);

        /* unmap the skb */
        if (skb) {
            pci_unmap_single(card->pdev, buf_addr, skb->len,
                    PCI_DMA_TODEVICE);
            dev_kfree_skb(skb);
        }
    }
    return 0;
}

static inline void
spider_net_kick_tx_dma(struct spider_net_card *card)
{
    struct spider_net_descr *descr;

    if (spider_net_read_reg(card, SPIDER_NET_GDTDMACCNTR) &
            SPIDER_NET_TX_DMA_EN)
        goto out;

    descr = card->tx_chain.tail;
    for (;;) {
        if (spider_net_get_descr_status(descr->hwdescr) ==
                SPIDER_NET_DESCR_CARDOWNED) {
            spider_net_write_reg(card, SPIDER_NET_GDTDCHA,
                    descr->bus_addr);
            spider_net_write_reg(card, SPIDER_NET_GDTDMACCNTR,
                    SPIDER_NET_DMA_TX_VALUE);
            break;
        }
        if (descr == card->tx_chain.head)
            break;
        descr = descr->next;
    }

out:
    mod_timer(&card->tx_timer, jiffies + SPIDER_NET_TX_TIMER);
}

static int
spider_net_xmit(struct sk_buff *skb, struct net_device *netdev)
{
    int cnt;
    struct spider_net_card *card = netdev_priv(netdev);

    spider_net_release_tx_chain(card, 0);

    if (spider_net_prepare_tx_descr(card, skb) != 0) {
        netdev->stats.tx_dropped++;
        netif_stop_queue(netdev);
        return NETDEV_TX_BUSY;
    }

    cnt = spider_net_set_low_watermark(card);
    if (cnt < 5)
        spider_net_kick_tx_dma(card);
    return NETDEV_TX_OK;
}

static void
spider_net_cleanup_tx_ring(struct spider_net_card *card)
{
    if ((spider_net_release_tx_chain(card, 0) != 0) &&
        (card->netdev->flags & IFF_UP)) {
        spider_net_kick_tx_dma(card);
        netif_wake_queue(card->netdev);
    }
}

static int
spider_net_do_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
{
    switch (cmd) {
    default:
        return -EOPNOTSUPP;
    }
}

static void
spider_net_pass_skb_up(struct spider_net_descr *descr,
               struct spider_net_card *card)
{
    struct spider_net_hw_descr *hwdescr = descr->hwdescr;
    struct sk_buff *skb = descr->skb;
    struct net_device *netdev = card->netdev;
    u32 data_status = hwdescr->data_status;
    u32 data_error = hwdescr->data_error;

    skb_put(skb, hwdescr->valid_size);

    /* the card seems to add 2 bytes of junk in front
     * of the ethernet frame */
#define SPIDER_MISALIGN     2
    skb_pull(skb, SPIDER_MISALIGN);
    skb->protocol = eth_type_trans(skb, netdev);

    /* checksum offload */
    skb_checksum_none_assert(skb);
    if (netdev->features & NETIF_F_RXCSUM) {
        if ( ( (data_status & SPIDER_NET_DATA_STATUS_CKSUM_MASK) ==
               SPIDER_NET_DATA_STATUS_CKSUM_MASK) &&
             !(data_error & SPIDER_NET_DATA_ERR_CKSUM_MASK))
            skb->ip_summed = CHECKSUM_UNNECESSARY;
    }

    if (data_status & SPIDER_NET_VLAN_PACKET) {
        /* further enhancements: HW-accel VLAN */
    }

    /* update netdevice statistics */
    netdev->stats.rx_packets++;
    netdev->stats.rx_bytes += skb->len;

    /* pass skb up to stack */
    netif_receive_skb(skb);
}

static void show_rx_chain(struct spider_net_card *card)
{
    struct spider_net_descr_chain *chain = &card->rx_chain;
    struct spider_net_descr *start= chain->tail;
    struct spider_net_descr *descr= start;
    struct spider_net_hw_descr *hwd = start->hwdescr;
    struct device *dev = &card->netdev->dev;
    u32 curr_desc, next_desc;
    int status;

    int tot = 0;
    int cnt = 0;
    int off = start - chain->ring;
    int cstat = hwd->dmac_cmd_status;

    dev_info(dev, "Total number of descrs=%d\n",
        chain->num_desc);
    dev_info(dev, "Chain tail located at descr=%d, status=0x%x\n",
        off, cstat);

    curr_desc = spider_net_read_reg(card, SPIDER_NET_GDACTDPA);
    next_desc = spider_net_read_reg(card, SPIDER_NET_GDACNEXTDA);

    status = cstat;
    do
    {
        hwd = descr->hwdescr;
        off = descr - chain->ring;
        status = hwd->dmac_cmd_status;

        if (descr == chain->head)
            dev_info(dev, "Chain head is at %d, head status=0x%x\n",
                     off, status);

        if (curr_desc == descr->bus_addr)
            dev_info(dev, "HW curr desc (GDACTDPA) is at %d, status=0x%x\n",
                     off, status);

        if (next_desc == descr->bus_addr)
            dev_info(dev, "HW next desc (GDACNEXTDA) is at %d, status=0x%x\n",
                     off, status);

        if (hwd->next_descr_addr == 0)
            dev_info(dev, "chain is cut at %d\n", off);

        if (cstat != status) {
            int from = (chain->num_desc + off - cnt) % chain->num_desc;
            int to = (chain->num_desc + off - 1) % chain->num_desc;
            dev_info(dev, "Have %d (from %d to %d) descrs "
                     "with stat=0x%08x\n", cnt, from, to, cstat);
            cstat = status;
            cnt = 0;
        }

        cnt ++;
        tot ++;
        descr = descr->next;
    } while (descr != start);

    dev_info(dev, "Last %d descrs with stat=0x%08x "
             "for a total of %d descrs\n", cnt, cstat, tot);

#ifdef DEBUG
    /* Now dump the whole ring */
    descr = start;
    do
    {
        struct spider_net_hw_descr *hwd = descr->hwdescr;
        status = spider_net_get_descr_status(hwd);
        cnt = descr - chain->ring;
        dev_info(dev, "Descr %d stat=0x%08x skb=%p\n",
                 cnt, status, descr->skb);
        dev_info(dev, "bus addr=%08x buf addr=%08x sz=%d\n",
                 descr->bus_addr, hwd->buf_addr, hwd->buf_size);
        dev_info(dev, "next=%08x result sz=%d valid sz=%d\n",
                 hwd->next_descr_addr, hwd->result_size,
                 hwd->valid_size);
        dev_info(dev, "dmac=%08x data stat=%08x data err=%08x\n",
                 hwd->dmac_cmd_status, hwd->data_status,
                 hwd->data_error);
        dev_info(dev, "\n");

        descr = descr->next;
    } while (descr != start);
#endif

}

static void spider_net_resync_head_ptr(struct spider_net_card *card)
{
    unsigned long flags;
    struct spider_net_descr_chain *chain = &card->rx_chain;
    struct spider_net_descr *descr;
    int i, status;

    /* Advance head pointer past any empty descrs */
    descr = chain->head;
    status = spider_net_get_descr_status(descr->hwdescr);

    if (status == SPIDER_NET_DESCR_NOT_IN_USE)
        return;

    spin_lock_irqsave(&chain->lock, flags);

    descr = chain->head;
    status = spider_net_get_descr_status(descr->hwdescr);
    for (i=0; i<chain->num_desc; i++) {
        if (status != SPIDER_NET_DESCR_CARDOWNED) break;
        descr = descr->next;
        status = spider_net_get_descr_status(descr->hwdescr);
    }
    chain->head = descr;

    spin_unlock_irqrestore(&chain->lock, flags);
}

static int spider_net_resync_tail_ptr(struct spider_net_card *card)
{
    struct spider_net_descr_chain *chain = &card->rx_chain;
    struct spider_net_descr *descr;
    int i, status;

    /* Advance tail pointer past any empty and reaped descrs */
    descr = chain->tail;
    status = spider_net_get_descr_status(descr->hwdescr);

    for (i=0; i<chain->num_desc; i++) {
        if ((status != SPIDER_NET_DESCR_CARDOWNED) &&
            (status != SPIDER_NET_DESCR_NOT_IN_USE)) break;
        descr = descr->next;
        status = spider_net_get_descr_status(descr->hwdescr);
    }
    chain->tail = descr;

    if ((i == chain->num_desc) || (i == 0))
        return 1;
    return 0;
}

static int
spider_net_decode_one_descr(struct spider_net_card *card)
{
    struct net_device *dev = card->netdev;
    struct spider_net_descr_chain *chain = &card->rx_chain;
    struct spider_net_descr *descr = chain->tail;
    struct spider_net_hw_descr *hwdescr = descr->hwdescr;
    u32 hw_buf_addr;
    int status;

    status = spider_net_get_descr_status(hwdescr);

    /* Nothing in the descriptor, or ring must be empty */
    if ((status == SPIDER_NET_DESCR_CARDOWNED) ||
        (status == SPIDER_NET_DESCR_NOT_IN_USE))
        return 0;

    /* descriptor definitively used -- move on tail */
    chain->tail = descr->next;

    /* unmap descriptor */
    hw_buf_addr = hwdescr->buf_addr;
    hwdescr->buf_addr = 0xffffffff;
    pci_unmap_single(card->pdev, hw_buf_addr,
            SPIDER_NET_MAX_FRAME, PCI_DMA_FROMDEVICE);

    if ( (status == SPIDER_NET_DESCR_RESPONSE_ERROR) ||
         (status == SPIDER_NET_DESCR_PROTECTION_ERROR) ||
         (status == SPIDER_NET_DESCR_FORCE_END) ) {
        if (netif_msg_rx_err(card))
            dev_err(&dev->dev,
                   "dropping RX descriptor with state %d\n", status);
        dev->stats.rx_dropped++;
        goto bad_desc;
    }

    if ( (status != SPIDER_NET_DESCR_COMPLETE) &&
         (status != SPIDER_NET_DESCR_FRAME_END) ) {
        if (netif_msg_rx_err(card))
            dev_err(&card->netdev->dev,
                   "RX descriptor with unknown state %d\n", status);
        card->spider_stats.rx_desc_unk_state++;
        goto bad_desc;
    }

    /* The cases we'll throw away the packet immediately */
    if (hwdescr->data_error & SPIDER_NET_DESTROY_RX_FLAGS) {
        if (netif_msg_rx_err(card))
            dev_err(&card->netdev->dev,
                   "error in received descriptor found, "
                   "data_status=x%08x, data_error=x%08x\n",
                   hwdescr->data_status, hwdescr->data_error);
        goto bad_desc;
    }

    if (hwdescr->dmac_cmd_status & SPIDER_NET_DESCR_BAD_STATUS) {
        dev_err(&card->netdev->dev, "bad status, cmd_status=x%08x\n",
                   hwdescr->dmac_cmd_status);
        pr_err("buf_addr=x%08x\n", hw_buf_addr);
        pr_err("buf_size=x%08x\n", hwdescr->buf_size);
        pr_err("next_descr_addr=x%08x\n", hwdescr->next_descr_addr);
        pr_err("result_size=x%08x\n", hwdescr->result_size);
        pr_err("valid_size=x%08x\n", hwdescr->valid_size);
        pr_err("data_status=x%08x\n", hwdescr->data_status);
        pr_err("data_error=x%08x\n", hwdescr->data_error);
        pr_err("which=%ld\n", descr - card->rx_chain.ring);

        card->spider_stats.rx_desc_error++;
        goto bad_desc;
    }

    /* Ok, we've got a packet in descr */
    spider_net_pass_skb_up(descr, card);
    descr->skb = NULL;
    hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
    return 1;

bad_desc:
    if (netif_msg_rx_err(card))
        show_rx_chain(card);
    dev_kfree_skb_irq(descr->skb);
    descr->skb = NULL;
    hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
    return 0;
}

static int spider_net_poll(struct napi_struct *napi, int budget)
{
    struct spider_net_card *card = container_of(napi, struct spider_net_card, napi);
    int packets_done = 0;

    while (packets_done < budget) {
        if (!spider_net_decode_one_descr(card))
            break;

        packets_done++;
    }

    if ((packets_done == 0) && (card->num_rx_ints != 0)) {
        if (!spider_net_resync_tail_ptr(card))
            packets_done = budget;
        spider_net_resync_head_ptr(card);
    }
    card->num_rx_ints = 0;

    spider_net_refill_rx_chain(card);
    spider_net_enable_rxdmac(card);

    spider_net_cleanup_tx_ring(card);

    /* if all packets are in the stack, enable interrupts and return 0 */
    /* if not, return 1 */
    if (packets_done < budget) {
        napi_complete(napi);
        spider_net_rx_irq_on(card);
        card->ignore_rx_ramfull = 0;
    }

    return packets_done;
}

static int
spider_net_change_mtu(struct net_device *netdev, int new_mtu)
{
    /* no need to re-alloc skbs or so -- the max mtu is about 2.3k
     * and mtu is outbound only anyway */
    if ( (new_mtu < SPIDER_NET_MIN_MTU ) ||
        (new_mtu > SPIDER_NET_MAX_MTU) )
        return -EINVAL;
    netdev->mtu = new_mtu;
    return 0;
}

static int
spider_net_set_mac(struct net_device *netdev, void *p)
{
    struct spider_net_card *card = netdev_priv(netdev);
    u32 macl, macu, regvalue;
    struct sockaddr *addr = p;

    if (!is_valid_ether_addr(addr->sa_data))
        return -EADDRNOTAVAIL;

    /* switch off GMACTPE and GMACRPE */
    regvalue = spider_net_read_reg(card, SPIDER_NET_GMACOPEMD);
    regvalue &= ~((1 << 5) | (1 << 6));
    spider_net_write_reg(card, SPIDER_NET_GMACOPEMD, regvalue);

    /* write mac */
    macu = (addr->sa_data[0]<<24) + (addr->sa_data[1]<<16) +
        (addr->sa_data[2]<<8) + (addr->sa_data[3]);
    macl = (addr->sa_data[4]<<8) + (addr->sa_data[5]);
    spider_net_write_reg(card, SPIDER_NET_GMACUNIMACU, macu);
    spider_net_write_reg(card, SPIDER_NET_GMACUNIMACL, macl);

    /* switch GMACTPE and GMACRPE back on */
    regvalue = spider_net_read_reg(card, SPIDER_NET_GMACOPEMD);
    regvalue |= ((1 << 5) | (1 << 6));
    spider_net_write_reg(card, SPIDER_NET_GMACOPEMD, regvalue);

    spider_net_set_promisc(card);

    /* look up, whether we have been successful */
    if (spider_net_get_mac_address(netdev))
        return -EADDRNOTAVAIL;
    if (memcmp(netdev->dev_addr,addr->sa_data,netdev->addr_len))
        return -EADDRNOTAVAIL;

    return 0;
}

static void
spider_net_link_reset(struct net_device *netdev)
{

    struct spider_net_card *card = netdev_priv(netdev);

    del_timer_sync(&card->aneg_timer);

    /* clear interrupt, block further interrupts */
    spider_net_write_reg(card, SPIDER_NET_GMACST,
                 spider_net_read_reg(card, SPIDER_NET_GMACST));
    spider_net_write_reg(card, SPIDER_NET_GMACINTEN, 0);

    /* reset phy and setup aneg */
    card->aneg_count = 0;
    card->medium = BCM54XX_COPPER;
    spider_net_setup_aneg(card);
    mod_timer(&card->aneg_timer, jiffies + SPIDER_NET_ANEG_TIMER);

}

static void
spider_net_handle_error_irq(struct spider_net_card *card, u32 status_reg,
                u32 error_reg1, u32 error_reg2)
{
    u32 i;
    int show_error = 1;

    /* check GHIINT0STS ************************************/
    if (status_reg)
        for (i = 0; i < 32; i++)
            if (status_reg & (1<<i))
                switch (i)
    {
    /* let error_reg1 and error_reg2 evaluation decide, what to do
    case SPIDER_NET_PHYINT:
    case SPIDER_NET_GMAC2INT:
    case SPIDER_NET_GMAC1INT:
    case SPIDER_NET_GFIFOINT:
    case SPIDER_NET_DMACINT:
    case SPIDER_NET_GSYSINT:
        break; */

    case SPIDER_NET_GIPSINT:
        show_error = 0;
        break;

    case SPIDER_NET_GPWOPCMPINT:
        /* PHY write operation completed */
        show_error = 0;
        break;
    case SPIDER_NET_GPROPCMPINT:
        /* PHY read operation completed */
        /* we don't use semaphores, as we poll for the completion
         * of the read operation in spider_net_read_phy. Should take
         * about 50 us */
        show_error = 0;
        break;
    case SPIDER_NET_GPWFFINT:
        /* PHY command queue full */
        if (netif_msg_intr(card))
            dev_err(&card->netdev->dev, "PHY write queue full\n");
        show_error = 0;
        break;

    /* case SPIDER_NET_GRMDADRINT: not used. print a message */
    /* case SPIDER_NET_GRMARPINT: not used. print a message */
    /* case SPIDER_NET_GRMMPINT: not used. print a message */

    case SPIDER_NET_GDTDEN0INT:
        /* someone has set TX_DMA_EN to 0 */
        show_error = 0;
        break;

    case SPIDER_NET_GDDDEN0INT: /* fallthrough */
    case SPIDER_NET_GDCDEN0INT: /* fallthrough */
    case SPIDER_NET_GDBDEN0INT: /* fallthrough */
    case SPIDER_NET_GDADEN0INT:
        /* someone has set RX_DMA_EN to 0 */
        show_error = 0;
        break;

    /* RX interrupts */
    case SPIDER_NET_GDDFDCINT:
    case SPIDER_NET_GDCFDCINT:
    case SPIDER_NET_GDBFDCINT:
    case SPIDER_NET_GDAFDCINT:
    /* case SPIDER_NET_GDNMINT: not used. print a message */
    /* case SPIDER_NET_GCNMINT: not used. print a message */
    /* case SPIDER_NET_GBNMINT: not used. print a message */
    /* case SPIDER_NET_GANMINT: not used. print a message */
    /* case SPIDER_NET_GRFNMINT: not used. print a message */
        show_error = 0;
        break;

    /* TX interrupts */
    case SPIDER_NET_GDTFDCINT:
        show_error = 0;
        break;
    case SPIDER_NET_GTTEDINT:
        show_error = 0;
        break;
    case SPIDER_NET_GDTDCEINT:
        /* chain end. If a descriptor should be sent, kick off
         * tx dma
        if (card->tx_chain.tail != card->tx_chain.head)
            spider_net_kick_tx_dma(card);
        */
        show_error = 0;
        break;

    /* case SPIDER_NET_G1TMCNTINT: not used. print a message */
    /* case SPIDER_NET_GFREECNTINT: not used. print a message */
    }

    /* check GHIINT1STS ************************************/
    if (error_reg1)
        for (i = 0; i < 32; i++)
            if (error_reg1 & (1<<i))
                switch (i)
    {
    case SPIDER_NET_GTMFLLINT:
        /* TX RAM full may happen on a usual case.
         * Logging is not needed. */
        show_error = 0;
        break;
    case SPIDER_NET_GRFDFLLINT: /* fallthrough */
    case SPIDER_NET_GRFCFLLINT: /* fallthrough */
    case SPIDER_NET_GRFBFLLINT: /* fallthrough */
    case SPIDER_NET_GRFAFLLINT: /* fallthrough */
    case SPIDER_NET_GRMFLLINT:
        /* Could happen when rx chain is full */
        if (card->ignore_rx_ramfull == 0) {
            card->ignore_rx_ramfull = 1;
            spider_net_resync_head_ptr(card);
            spider_net_refill_rx_chain(card);
            spider_net_enable_rxdmac(card);
            card->num_rx_ints ++;
            napi_schedule(&card->napi);
        }
        show_error = 0;
        break;

    /* case SPIDER_NET_GTMSHTINT: problem, print a message */
    case SPIDER_NET_GDTINVDINT:
        /* allrighty. tx from previous descr ok */
        show_error = 0;
        break;

    /* chain end */
    case SPIDER_NET_GDDDCEINT: /* fallthrough */
    case SPIDER_NET_GDCDCEINT: /* fallthrough */
    case SPIDER_NET_GDBDCEINT: /* fallthrough */
    case SPIDER_NET_GDADCEINT:
        spider_net_resync_head_ptr(card);
        spider_net_refill_rx_chain(card);
        spider_net_enable_rxdmac(card);
        card->num_rx_ints ++;
        napi_schedule(&card->napi);
        show_error = 0;
        break;

    /* invalid descriptor */
    case SPIDER_NET_GDDINVDINT: /* fallthrough */
    case SPIDER_NET_GDCINVDINT: /* fallthrough */
    case SPIDER_NET_GDBINVDINT: /* fallthrough */
    case SPIDER_NET_GDAINVDINT:
        /* Could happen when rx chain is full */
        spider_net_resync_head_ptr(card);
        spider_net_refill_rx_chain(card);
        spider_net_enable_rxdmac(card);
        card->num_rx_ints ++;
        napi_schedule(&card->napi);
        show_error = 0;
        break;

    /* case SPIDER_NET_GDTRSERINT: problem, print a message */
    /* case SPIDER_NET_GDDRSERINT: problem, print a message */
    /* case SPIDER_NET_GDCRSERINT: problem, print a message */
    /* case SPIDER_NET_GDBRSERINT: problem, print a message */
    /* case SPIDER_NET_GDARSERINT: problem, print a message */
    /* case SPIDER_NET_GDSERINT: problem, print a message */
    /* case SPIDER_NET_GDTPTERINT: problem, print a message */
    /* case SPIDER_NET_GDDPTERINT: problem, print a message */
    /* case SPIDER_NET_GDCPTERINT: problem, print a message */
    /* case SPIDER_NET_GDBPTERINT: problem, print a message */
    /* case SPIDER_NET_GDAPTERINT: problem, print a message */
    default:
        show_error = 1;
        break;
    }

    /* check GHIINT2STS ************************************/
    if (error_reg2)
        for (i = 0; i < 32; i++)
            if (error_reg2 & (1<<i))
                switch (i)
    {
    /* there is nothing we can (want  to) do at this time. Log a
     * message, we can switch on and off the specific values later on
    case SPIDER_NET_GPROPERINT:
    case SPIDER_NET_GMCTCRSNGINT:
    case SPIDER_NET_GMCTLCOLINT:
    case SPIDER_NET_GMCTTMOTINT:
    case SPIDER_NET_GMCRCAERINT:
    case SPIDER_NET_GMCRCALERINT:
    case SPIDER_NET_GMCRALNERINT:
    case SPIDER_NET_GMCROVRINT:
    case SPIDER_NET_GMCRRNTINT:
    case SPIDER_NET_GMCRRXERINT:
    case SPIDER_NET_GTITCSERINT:
    case SPIDER_NET_GTIFMTERINT:
    case SPIDER_NET_GTIPKTRVKINT:
    case SPIDER_NET_GTISPINGINT:
    case SPIDER_NET_GTISADNGINT:
    case SPIDER_NET_GTISPDNGINT:
    case SPIDER_NET_GRIFMTERINT:
    case SPIDER_NET_GRIPKTRVKINT:
    case SPIDER_NET_GRISPINGINT:
    case SPIDER_NET_GRISADNGINT:
    case SPIDER_NET_GRISPDNGINT:
        break;
    */
        default:
            break;
    }

    if ((show_error) && (netif_msg_intr(card)) && net_ratelimit())
        dev_err(&card->netdev->dev, "Error interrupt, GHIINT0STS = 0x%08x, "
               "GHIINT1STS = 0x%08x, GHIINT2STS = 0x%08x\n",
               status_reg, error_reg1, error_reg2);

    /* clear interrupt sources */
    spider_net_write_reg(card, SPIDER_NET_GHIINT1STS, error_reg1);
    spider_net_write_reg(card, SPIDER_NET_GHIINT2STS, error_reg2);
}

static irqreturn_t
spider_net_interrupt(int irq, void *ptr)
{
    struct net_device *netdev = ptr;
    struct spider_net_card *card = netdev_priv(netdev);
    u32 status_reg, error_reg1, error_reg2;

    status_reg = spider_net_read_reg(card, SPIDER_NET_GHIINT0STS);
    error_reg1 = spider_net_read_reg(card, SPIDER_NET_GHIINT1STS);
    error_reg2 = spider_net_read_reg(card, SPIDER_NET_GHIINT2STS);

    if (!(status_reg & SPIDER_NET_INT0_MASK_VALUE) &&
        !(error_reg1 & SPIDER_NET_INT1_MASK_VALUE) &&
        !(error_reg2 & SPIDER_NET_INT2_MASK_VALUE))
        return IRQ_NONE;

    if (status_reg & SPIDER_NET_RXINT ) {
        spider_net_rx_irq_off(card);
        napi_schedule(&card->napi);
        card->num_rx_ints ++;
    }
    if (status_reg & SPIDER_NET_TXINT)
        napi_schedule(&card->napi);

    if (status_reg & SPIDER_NET_LINKINT)
        spider_net_link_reset(netdev);

    if (status_reg & SPIDER_NET_ERRINT )
        spider_net_handle_error_irq(card, status_reg,
                        error_reg1, error_reg2);

    /* clear interrupt sources */
    spider_net_write_reg(card, SPIDER_NET_GHIINT0STS, status_reg);

    return IRQ_HANDLED;
}

#ifdef CONFIG_NET_POLL_CONTROLLER

static void
spider_net_poll_controller(struct net_device *netdev)
{
    disable_irq(netdev->irq);
    spider_net_interrupt(netdev->irq, netdev);
    enable_irq(netdev->irq);
}
#endif /* CONFIG_NET_POLL_CONTROLLER */

static void
spider_net_enable_interrupts(struct spider_net_card *card)
{
    spider_net_write_reg(card, SPIDER_NET_GHIINT0MSK,
                 SPIDER_NET_INT0_MASK_VALUE);
    spider_net_write_reg(card, SPIDER_NET_GHIINT1MSK,
                 SPIDER_NET_INT1_MASK_VALUE);
    spider_net_write_reg(card, SPIDER_NET_GHIINT2MSK,
                 SPIDER_NET_INT2_MASK_VALUE);
}

static void
spider_net_disable_interrupts(struct spider_net_card *card)
{
    spider_net_write_reg(card, SPIDER_NET_GHIINT0MSK, 0);
    spider_net_write_reg(card, SPIDER_NET_GHIINT1MSK, 0);
    spider_net_write_reg(card, SPIDER_NET_GHIINT2MSK, 0);
    spider_net_write_reg(card, SPIDER_NET_GMACINTEN, 0);
}

static void
spider_net_init_card(struct spider_net_card *card)
{
    spider_net_write_reg(card, SPIDER_NET_CKRCTRL,
                 SPIDER_NET_CKRCTRL_STOP_VALUE);

    spider_net_write_reg(card, SPIDER_NET_CKRCTRL,
                 SPIDER_NET_CKRCTRL_RUN_VALUE);

    /* trigger ETOMOD signal */
    spider_net_write_reg(card, SPIDER_NET_GMACOPEMD,
        spider_net_read_reg(card, SPIDER_NET_GMACOPEMD) | 0x4);

    spider_net_disable_interrupts(card);
}

static void
spider_net_enable_card(struct spider_net_card *card)
{
    int i;
    /* the following array consists of (register),(value) pairs
     * that are set in this function. A register of 0 ends the list */
    u32 regs[][2] = {
        { SPIDER_NET_GRESUMINTNUM, 0 },
        { SPIDER_NET_GREINTNUM, 0 },

        /* set interrupt frame number registers */
        /* clear the single DMA engine registers first */
        { SPIDER_NET_GFAFRMNUM, SPIDER_NET_GFXFRAMES_VALUE },
        { SPIDER_NET_GFBFRMNUM, SPIDER_NET_GFXFRAMES_VALUE },
        { SPIDER_NET_GFCFRMNUM, SPIDER_NET_GFXFRAMES_VALUE },
        { SPIDER_NET_GFDFRMNUM, SPIDER_NET_GFXFRAMES_VALUE },
        /* then set, what we really need */
        { SPIDER_NET_GFFRMNUM, SPIDER_NET_FRAMENUM_VALUE },

        /* timer counter registers and stuff */
        { SPIDER_NET_GFREECNNUM, 0 },
        { SPIDER_NET_GONETIMENUM, 0 },
        { SPIDER_NET_GTOUTFRMNUM, 0 },

        /* RX mode setting */
        { SPIDER_NET_GRXMDSET, SPIDER_NET_RXMODE_VALUE },
        /* TX mode setting */
        { SPIDER_NET_GTXMDSET, SPIDER_NET_TXMODE_VALUE },
        /* IPSEC mode setting */
        { SPIDER_NET_GIPSECINIT, SPIDER_NET_IPSECINIT_VALUE },

        { SPIDER_NET_GFTRESTRT, SPIDER_NET_RESTART_VALUE },

        { SPIDER_NET_GMRWOLCTRL, 0 },
        { SPIDER_NET_GTESTMD, 0x10000000 },
        { SPIDER_NET_GTTQMSK, 0x00400040 },

        { SPIDER_NET_GMACINTEN, 0 },

        /* flow control stuff */
        { SPIDER_NET_GMACAPAUSE, SPIDER_NET_MACAPAUSE_VALUE },
        { SPIDER_NET_GMACTXPAUSE, SPIDER_NET_TXPAUSE_VALUE },

        { SPIDER_NET_GMACBSTLMT, SPIDER_NET_BURSTLMT_VALUE },
        { 0, 0}
    };

    i = 0;
    while (regs[i][0]) {
        spider_net_write_reg(card, regs[i][0], regs[i][1]);
        i++;
    }

    /* clear unicast filter table entries 1 to 14 */
    for (i = 1; i <= 14; i++) {
        spider_net_write_reg(card,
                     SPIDER_NET_GMRUAFILnR + i * 8,
                     0x00080000);
        spider_net_write_reg(card,
                     SPIDER_NET_GMRUAFILnR + i * 8 + 4,
                     0x00000000);
    }

    spider_net_write_reg(card, SPIDER_NET_GMRUA0FIL15R, 0x08080000);

    spider_net_write_reg(card, SPIDER_NET_ECMODE, SPIDER_NET_ECMODE_VALUE);

    /* set chain tail address for RX chains and
     * enable DMA */
    spider_net_enable_rxchtails(card);
    spider_net_enable_rxdmac(card);

    spider_net_write_reg(card, SPIDER_NET_GRXDMAEN, SPIDER_NET_WOL_VALUE);

    spider_net_write_reg(card, SPIDER_NET_GMACLENLMT,
                 SPIDER_NET_LENLMT_VALUE);
    spider_net_write_reg(card, SPIDER_NET_GMACOPEMD,
                 SPIDER_NET_OPMODE_VALUE);

    spider_net_write_reg(card, SPIDER_NET_GDTDMACCNTR,
                 SPIDER_NET_GDTBSTA);
}

static int
spider_net_download_firmware(struct spider_net_card *card,
                 const void *firmware_ptr)
{
    int sequencer, i;
    const u32 *fw_ptr = firmware_ptr;

    /* stop sequencers */
    spider_net_write_reg(card, SPIDER_NET_GSINIT,
                 SPIDER_NET_STOP_SEQ_VALUE);

    for (sequencer = 0; sequencer < SPIDER_NET_FIRMWARE_SEQS;
         sequencer++) {
        spider_net_write_reg(card,
                     SPIDER_NET_GSnPRGADR + sequencer * 8, 0);
        for (i = 0; i < SPIDER_NET_FIRMWARE_SEQWORDS; i++) {
            spider_net_write_reg(card, SPIDER_NET_GSnPRGDAT +
                         sequencer * 8, *fw_ptr);
            fw_ptr++;
        }
    }

    if (spider_net_read_reg(card, SPIDER_NET_GSINIT))
        return -EIO;

    spider_net_write_reg(card, SPIDER_NET_GSINIT,
                 SPIDER_NET_RUN_SEQ_VALUE);

    return 0;
}

static int
spider_net_init_firmware(struct spider_net_card *card)
{
    struct firmware *firmware = NULL;
    struct device_node *dn;
    const u8 *fw_prop = NULL;
    int err = -ENOENT;
    int fw_size;

    if (request_firmware((const struct firmware **)&firmware,
                 SPIDER_NET_FIRMWARE_NAME, &card->pdev->dev) == 0) {
        if ( (firmware->size != SPIDER_NET_FIRMWARE_LEN) &&
             netif_msg_probe(card) ) {
            dev_err(&card->netdev->dev,
                   "Incorrect size of spidernet firmware in " \
                   "filesystem. Looking in host firmware...\n");
            goto try_host_fw;
        }
        err = spider_net_download_firmware(card, firmware->data);

        release_firmware(firmware);
        if (err)
            goto try_host_fw;

        goto done;
    }

try_host_fw:
    dn = pci_device_to_OF_node(card->pdev);
    if (!dn)
        goto out_err;

    fw_prop = of_get_property(dn, "firmware", &fw_size);
    if (!fw_prop)
        goto out_err;

    if ( (fw_size != SPIDER_NET_FIRMWARE_LEN) &&
         netif_msg_probe(card) ) {
        dev_err(&card->netdev->dev,
               "Incorrect size of spidernet firmware in host firmware\n");
        goto done;
    }

    err = spider_net_download_firmware(card, fw_prop);

done:
    return err;
out_err:
    if (netif_msg_probe(card))
        dev_err(&card->netdev->dev,
               "Couldn't find spidernet firmware in filesystem " \
               "or host firmware\n");
    return err;
}

int
spider_net_open(struct net_device *netdev)
{
    struct spider_net_card *card = netdev_priv(netdev);
    int result;

    result = spider_net_init_firmware(card);
    if (result)
        goto init_firmware_failed;

    /* start probing with copper */
    card->aneg_count = 0;
    card->medium = BCM54XX_COPPER;
    spider_net_setup_aneg(card);
    if (card->phy.def->phy_id)
        mod_timer(&card->aneg_timer, jiffies + SPIDER_NET_ANEG_TIMER);

    result = spider_net_init_chain(card, &card->tx_chain);
    if (result)
        goto alloc_tx_failed;
    card->low_watermark = NULL;

    result = spider_net_init_chain(card, &card->rx_chain);
    if (result)
        goto alloc_rx_failed;

    /* Allocate rx skbs */
    if (spider_net_alloc_rx_skbs(card))
        goto alloc_skbs_failed;

    spider_net_set_multi(netdev);

    /* further enhancement: setup hw vlan, if needed */

    result = -EBUSY;
    if (request_irq(netdev->irq, spider_net_interrupt,
                 IRQF_SHARED, netdev->name, netdev))
        goto register_int_failed;

    spider_net_enable_card(card);

    netif_start_queue(netdev);
    netif_carrier_on(netdev);
    napi_enable(&card->napi);

    spider_net_enable_interrupts(card);

    return 0;

register_int_failed:
    spider_net_free_rx_chain_contents(card);
alloc_skbs_failed:
    spider_net_free_chain(card, &card->rx_chain);
alloc_rx_failed:
    spider_net_free_chain(card, &card->tx_chain);
alloc_tx_failed:
    del_timer_sync(&card->aneg_timer);
init_firmware_failed:
    return result;
}

static void spider_net_link_phy(unsigned long data)
{
    struct spider_net_card *card = (struct spider_net_card *)data;
    struct mii_phy *phy = &card->phy;

    /* if link didn't come up after SPIDER_NET_ANEG_TIMEOUT tries, setup phy again */
    if (card->aneg_count > SPIDER_NET_ANEG_TIMEOUT) {

        pr_debug("%s: link is down trying to bring it up\n",
             card->netdev->name);

        switch (card->medium) {
        case BCM54XX_COPPER:
            /* enable fiber with autonegotiation first */
            if (phy->def->ops->enable_fiber)
                phy->def->ops->enable_fiber(phy, 1);
            card->medium = BCM54XX_FIBER;
            break;

        case BCM54XX_FIBER:
            /* fiber didn't come up, try to disable fiber autoneg */
            if (phy->def->ops->enable_fiber)
                phy->def->ops->enable_fiber(phy, 0);
            card->medium = BCM54XX_UNKNOWN;
            break;

        case BCM54XX_UNKNOWN:
            /* copper, fiber with and without failed,
             * retry from beginning */
            spider_net_setup_aneg(card);
            card->medium = BCM54XX_COPPER;
            break;
        }

        card->aneg_count = 0;
        mod_timer(&card->aneg_timer, jiffies + SPIDER_NET_ANEG_TIMER);
        return;
    }

    /* link still not up, try again later */
    if (!(phy->def->ops->poll_link(phy))) {
        card->aneg_count++;
        mod_timer(&card->aneg_timer, jiffies + SPIDER_NET_ANEG_TIMER);
        return;
    }

    /* link came up, get abilities */
    phy->def->ops->read_link(phy);

    spider_net_write_reg(card, SPIDER_NET_GMACST,
                 spider_net_read_reg(card, SPIDER_NET_GMACST));
    spider_net_write_reg(card, SPIDER_NET_GMACINTEN, 0x4);

    if (phy->speed == 1000)
        spider_net_write_reg(card, SPIDER_NET_GMACMODE, 0x00000001);
    else
        spider_net_write_reg(card, SPIDER_NET_GMACMODE, 0);

    card->aneg_count = 0;

    pr_info("%s: link up, %i Mbps, %s-duplex %sautoneg.\n",
        card->netdev->name, phy->speed,
        phy->duplex == 1 ? "Full" : "Half",
        phy->autoneg == 1 ? "" : "no ");
}

static int
spider_net_setup_phy(struct spider_net_card *card)
{
    struct mii_phy *phy = &card->phy;

    spider_net_write_reg(card, SPIDER_NET_GDTDMASEL,
                 SPIDER_NET_DMASEL_VALUE);
    spider_net_write_reg(card, SPIDER_NET_GPCCTRL,
                 SPIDER_NET_PHY_CTRL_VALUE);

    phy->dev = card->netdev;
    phy->mdio_read = spider_net_read_phy;
    phy->mdio_write = spider_net_write_phy;

    for (phy->mii_id = 1; phy->mii_id <= 31; phy->mii_id++) {
        unsigned short id;
        id = spider_net_read_phy(card->netdev, phy->mii_id, MII_BMSR);
        if (id != 0x0000 && id != 0xffff) {
            if (!sungem_phy_probe(phy, phy->mii_id)) {
                pr_info("Found %s.\n", phy->def->name);
                break;
            }
        }
    }

    return 0;
}

static void
spider_net_workaround_rxramfull(struct spider_net_card *card)
{
    int i, sequencer = 0;

    /* cancel reset */
    spider_net_write_reg(card, SPIDER_NET_CKRCTRL,
                 SPIDER_NET_CKRCTRL_RUN_VALUE);

    /* empty sequencer data */
    for (sequencer = 0; sequencer < SPIDER_NET_FIRMWARE_SEQS;
         sequencer++) {
        spider_net_write_reg(card, SPIDER_NET_GSnPRGADR +
                     sequencer * 8, 0x0);
        for (i = 0; i < SPIDER_NET_FIRMWARE_SEQWORDS; i++) {
            spider_net_write_reg(card, SPIDER_NET_GSnPRGDAT +
                         sequencer * 8, 0x0);
        }
    }

    /* set sequencer operation */
    spider_net_write_reg(card, SPIDER_NET_GSINIT, 0x000000fe);

    /* reset */
    spider_net_write_reg(card, SPIDER_NET_CKRCTRL,
                 SPIDER_NET_CKRCTRL_STOP_VALUE);
}

int
spider_net_stop(struct net_device *netdev)
{
    struct spider_net_card *card = netdev_priv(netdev);

    napi_disable(&card->napi);
    netif_carrier_off(netdev);
    netif_stop_queue(netdev);
    del_timer_sync(&card->tx_timer);
    del_timer_sync(&card->aneg_timer);

    spider_net_disable_interrupts(card);

    free_irq(netdev->irq, netdev);

    spider_net_write_reg(card, SPIDER_NET_GDTDMACCNTR,
                 SPIDER_NET_DMA_TX_FEND_VALUE);

    /* turn off DMA, force end */
    spider_net_disable_rxdmac(card);

    /* release chains */
    spider_net_release_tx_chain(card, 1);
    spider_net_free_rx_chain_contents(card);

    spider_net_free_chain(card, &card->tx_chain);
    spider_net_free_chain(card, &card->rx_chain);

    return 0;
}

static void
spider_net_tx_timeout_task(struct work_struct *work)
{
    struct spider_net_card *card =
        container_of(work, struct spider_net_card, tx_timeout_task);
    struct net_device *netdev = card->netdev;

    if (!(netdev->flags & IFF_UP))
        goto out;

    netif_device_detach(netdev);
    spider_net_stop(netdev);

    spider_net_workaround_rxramfull(card);
    spider_net_init_card(card);

    if (spider_net_setup_phy(card))
        goto out;

    spider_net_open(netdev);
    spider_net_kick_tx_dma(card);
    netif_device_attach(netdev);

out:
    atomic_dec(&card->tx_timeout_task_counter);
}

static void
spider_net_tx_timeout(struct net_device *netdev)
{
    struct spider_net_card *card;

    card = netdev_priv(netdev);
    atomic_inc(&card->tx_timeout_task_counter);
    if (netdev->flags & IFF_UP)
        schedule_work(&card->tx_timeout_task);
    else
        atomic_dec(&card->tx_timeout_task_counter);
    card->spider_stats.tx_timeouts++;
}

static const struct net_device_ops spider_net_ops = {
    .ndo_open       = spider_net_open,
    .ndo_stop       = spider_net_stop,
    .ndo_start_xmit     = spider_net_xmit,
    .ndo_set_rx_mode    = spider_net_set_multi,
    .ndo_set_mac_address    = spider_net_set_mac,
    .ndo_change_mtu     = spider_net_change_mtu,
    .ndo_do_ioctl       = spider_net_do_ioctl,
    .ndo_tx_timeout     = spider_net_tx_timeout,
    .ndo_validate_addr  = eth_validate_addr,
    /* HW VLAN */
#ifdef CONFIG_NET_POLL_CONTROLLER
    /* poll controller */
    .ndo_poll_controller    = spider_net_poll_controller,
#endif /* CONFIG_NET_POLL_CONTROLLER */
};

static void
spider_net_setup_netdev_ops(struct net_device *netdev)
{
    netdev->netdev_ops = &spider_net_ops;
    netdev->watchdog_timeo = SPIDER_NET_WATCHDOG_TIMEOUT;
    /* ethtool ops */
    netdev->ethtool_ops = &spider_net_ethtool_ops;
}

static int
spider_net_setup_netdev(struct spider_net_card *card)
{
    int result;
    struct net_device *netdev = card->netdev;
    struct device_node *dn;
    struct sockaddr addr;
    const u8 *mac;

    SET_NETDEV_DEV(netdev, &card->pdev->dev);

    pci_set_drvdata(card->pdev, netdev);

    init_timer(&card->tx_timer);
    card->tx_timer.function =
        (void (*)(unsigned long)) spider_net_cleanup_tx_ring;
    card->tx_timer.data = (unsigned long) card;
    netdev->irq = card->pdev->irq;

    card->aneg_count = 0;
    init_timer(&card->aneg_timer);
    card->aneg_timer.function = spider_net_link_phy;
    card->aneg_timer.data = (unsigned long) card;

    netif_napi_add(netdev, &card->napi,
               spider_net_poll, SPIDER_NET_NAPI_WEIGHT);

    spider_net_setup_netdev_ops(netdev);

    netdev->hw_features = NETIF_F_RXCSUM | NETIF_F_IP_CSUM;
    if (SPIDER_NET_RX_CSUM_DEFAULT)
        netdev->features |= NETIF_F_RXCSUM;
    netdev->features |= NETIF_F_IP_CSUM | NETIF_F_LLTX;
    /* some time: NETIF_F_HW_VLAN_TX | NETIF_F_HW_VLAN_RX |
     *      NETIF_F_HW_VLAN_FILTER */

    netdev->irq = card->pdev->irq;
    card->num_rx_ints = 0;
    card->ignore_rx_ramfull = 0;

    dn = pci_device_to_OF_node(card->pdev);
    if (!dn)
        return -EIO;

    mac = of_get_property(dn, "local-mac-address", NULL);
    if (!mac)
        return -EIO;
    memcpy(addr.sa_data, mac, ETH_ALEN);

    result = spider_net_set_mac(netdev, &addr);
    if ((result) && (netif_msg_probe(card)))
        dev_err(&card->netdev->dev,
                "Failed to set MAC address: %i\n", result);

    result = register_netdev(netdev);
    if (result) {
        if (netif_msg_probe(card))
            dev_err(&card->netdev->dev,
                    "Couldn't register net_device: %i\n", result);
        return result;
    }

    if (netif_msg_probe(card))
        pr_info("Initialized device %s.\n", netdev->name);

    return 0;
}

static struct spider_net_card *
spider_net_alloc_card(void)
{
    struct net_device *netdev;
    struct spider_net_card *card;
    size_t alloc_size;

    alloc_size = sizeof(struct spider_net_card) +
       (tx_descriptors + rx_descriptors) * sizeof(struct spider_net_descr);
    netdev = alloc_etherdev(alloc_size);
    if (!netdev)
        return NULL;

    card = netdev_priv(netdev);
    card->netdev = netdev;
    card->msg_enable = SPIDER_NET_DEFAULT_MSG;
    INIT_WORK(&card->tx_timeout_task, spider_net_tx_timeout_task);
    init_waitqueue_head(&card->waitq);
    atomic_set(&card->tx_timeout_task_counter, 0);

    card->rx_chain.num_desc = rx_descriptors;
    card->rx_chain.ring = card->darray;
    card->tx_chain.num_desc = tx_descriptors;
    card->tx_chain.ring = card->darray + rx_descriptors;

    return card;
}

static void
spider_net_undo_pci_setup(struct spider_net_card *card)
{
    iounmap(card->regs);
    pci_release_regions(card->pdev);
}

static struct spider_net_card *
spider_net_setup_pci_dev(struct pci_dev *pdev)
{
    struct spider_net_card *card;
    unsigned long mmio_start, mmio_len;

    if (pci_enable_device(pdev)) {
        dev_err(&pdev->dev, "Couldn't enable PCI device\n");
        return NULL;
    }

    if (!(pci_resource_flags(pdev, 0) & IORESOURCE_MEM)) {
        dev_err(&pdev->dev,
                "Couldn't find proper PCI device base address.\n");
        goto out_disable_dev;
    }

    if (pci_request_regions(pdev, spider_net_driver_name)) {
        dev_err(&pdev->dev,
                "Couldn't obtain PCI resources, aborting.\n");
        goto out_disable_dev;
    }

    pci_set_master(pdev);

    card = spider_net_alloc_card();
    if (!card) {
        dev_err(&pdev->dev,
                "Couldn't allocate net_device structure, aborting.\n");
        goto out_release_regions;
    }
    card->pdev = pdev;

    /* fetch base address and length of first resource */
    mmio_start = pci_resource_start(pdev, 0);
    mmio_len = pci_resource_len(pdev, 0);

    card->netdev->mem_start = mmio_start;
    card->netdev->mem_end = mmio_start + mmio_len;
    card->regs = ioremap(mmio_start, mmio_len);

    if (!card->regs) {
        dev_err(&pdev->dev,
                "Couldn't obtain PCI resources, aborting.\n");
        goto out_release_regions;
    }

    return card;

out_release_regions:
    pci_release_regions(pdev);
out_disable_dev:
    pci_disable_device(pdev);
    pci_set_drvdata(pdev, NULL);
    return NULL;
}

static int __devinit
spider_net_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
    int err = -EIO;
    struct spider_net_card *card;

    card = spider_net_setup_pci_dev(pdev);
    if (!card)
        goto out;

    spider_net_workaround_rxramfull(card);
    spider_net_init_card(card);

    err = spider_net_setup_phy(card);
    if (err)
        goto out_undo_pci;

    err = spider_net_setup_netdev(card);
    if (err)
        goto out_undo_pci;

    return 0;

out_undo_pci:
    spider_net_undo_pci_setup(card);
    free_netdev(card->netdev);
out:
    return err;
}

static void __devexit
spider_net_remove(struct pci_dev *pdev)
{
    struct net_device *netdev;
    struct spider_net_card *card;

    netdev = pci_get_drvdata(pdev);
    card = netdev_priv(netdev);

    wait_event(card->waitq,
           atomic_read(&card->tx_timeout_task_counter) == 0);

    unregister_netdev(netdev);

    /* switch off card */
    spider_net_write_reg(card, SPIDER_NET_CKRCTRL,
                 SPIDER_NET_CKRCTRL_STOP_VALUE);
    spider_net_write_reg(card, SPIDER_NET_CKRCTRL,
                 SPIDER_NET_CKRCTRL_RUN_VALUE);

    spider_net_undo_pci_setup(card);
    free_netdev(netdev);
}

static struct pci_driver spider_net_driver = {
    .name       = spider_net_driver_name,
    .id_table   = spider_net_pci_tbl,
    .probe      = spider_net_probe,
    .remove     = __devexit_p(spider_net_remove)
};

static int __init spider_net_init(void)
{
    printk(KERN_INFO "Spidernet version %s.\n", VERSION);

    if (rx_descriptors < SPIDER_NET_RX_DESCRIPTORS_MIN) {
        rx_descriptors = SPIDER_NET_RX_DESCRIPTORS_MIN;
        pr_info("adjusting rx descriptors to %i.\n", rx_descriptors);
    }
    if (rx_descriptors > SPIDER_NET_RX_DESCRIPTORS_MAX) {
        rx_descriptors = SPIDER_NET_RX_DESCRIPTORS_MAX;
        pr_info("adjusting rx descriptors to %i.\n", rx_descriptors);
    }
    if (tx_descriptors < SPIDER_NET_TX_DESCRIPTORS_MIN) {
        tx_descriptors = SPIDER_NET_TX_DESCRIPTORS_MIN;
        pr_info("adjusting tx descriptors to %i.\n", tx_descriptors);
    }
    if (tx_descriptors > SPIDER_NET_TX_DESCRIPTORS_MAX) {
        tx_descriptors = SPIDER_NET_TX_DESCRIPTORS_MAX;
        pr_info("adjusting tx descriptors to %i.\n", tx_descriptors);
    }

    return pci_register_driver(&spider_net_driver);
}

static void __exit spider_net_cleanup(void)
{
    pci_unregister_driver(&spider_net_driver);
}

module_init(spider_net_init);
module_exit(spider_net_cleanup);