text: // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   * Network device driver for Cell Processor-Based Blade and Celleb platform
   *
   * (C) Copyright IBM Corp. 2005
   * (C) Copyright 2006 TOSHIBA CORPORATION
   *
   * Authors : Utz Bacher <utz.bacher@de.ibm.com>
   *           Jens Osterkamp <Jens.Osterkamp@de.ibm.com>
   */
  
  #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 <net/checksum.h>
  
  #include "spider_net.h"
  
  MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com> and Jens Osterkamp " \
  	      "<Jens.Osterkamp@de.ibm.com>");
  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 const struct pci_device_id 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);
  
  /**
   * spider_net_read_reg - reads an SMMIO register of a card
   * @card: device structure
   * @reg: register to read from
   *
   * returns the content of the specified SMMIO register.
   */
  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);
  }
  
  /**
   * spider_net_write_reg - writes to an SMMIO register of a card
   * @card: device structure
   * @reg: register to write to
   * @value: value to write into the specified SMMIO register
   */
  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);
  }
  
  /**
   * spider_net_write_phy - write to phy register
   * @netdev: adapter to be written to
   * @mii_id: id of MII
   * @reg: PHY register
   * @val: value to be written to phy register
   *
   * spider_net_write_phy_register writes to an arbitrary PHY
   * register via the spider GPCWOPCMD register. We assume the queue does
   * not run full (not more than 15 commands outstanding).
   **/
  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);
  }
  
  /**
   * spider_net_read_phy - read from phy register
   * @netdev: network device to be read from
   * @mii_id: id of MII
   * @reg: PHY register
   *
   * Returns value read from PHY register
   *
   * spider_net_write_phy reads from an arbitrary PHY
   * register via the spider GPCROPCMD register
   **/
  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;
  }
  
  /**
   * spider_net_setup_aneg - initial auto-negotiation setup
   * @card: device structure
   **/
  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);
  
  }
  
  /**
   * spider_net_rx_irq_off - switch off rx irq on this spider card
   * @card: device structure
   *
   * switches off rx irq by masking them out in the GHIINTnMSK register
   */
  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);
  }
  
  /**
   * spider_net_rx_irq_on - switch on rx irq on this spider card
   * @card: device structure
   *
   * switches on rx irq by enabling them in the GHIINTnMSK register
   */
  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);
  }
  
  /**
   * spider_net_set_promisc - sets the unicast address or the promiscuous mode
   * @card: card structure
   *
   * spider_net_set_promisc sets the unicast destination address filter and
   * thus either allows for non-promisc mode or promisc mode
   */
  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);
  	}
  }
  
  /**
   * spider_net_get_descr_status -- returns the status of a descriptor
   * @hwdescr: descriptor to look at
   *
   * returns the status as in the dmac_cmd_status field of the descriptor
   */
  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;
  }
  
  /**
   * spider_net_free_chain - free descriptor chain
   * @card: card structure
   * @chain: address of chain
   *
   */
  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 * sizeof(struct spider_net_hw_descr),
  			  chain->hwring, chain->dma_addr);
  }
  
  /**
   * spider_net_init_chain - alloc and link descriptor chain
   * @card: card structure
   * @chain: address of chain
   *
   * We manage a circular list that mirrors the hardware structure,
   * except that the hardware uses bus addresses.
   *
   * Returns 0 on success, <0 on failure
   */
  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;
  
  	/* 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;
  }
  
  /**
   * spider_net_free_rx_chain_contents - frees descr contents in rx chain
   * @card: card structure
   *
   * returns 0 on success, <0 on failure
   */
  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) {
  			dma_unmap_single(&card->pdev->dev,
  					 descr->hwdescr->buf_addr,
  					 SPIDER_NET_MAX_FRAME,
  					 DMA_BIDIRECTIONAL);
  			dev_kfree_skb(descr->skb);
  			descr->skb = NULL;
  		}
  		descr = descr->next;
  	} while (descr != card->rx_chain.head);
  }
  
  /**
   * spider_net_prepare_rx_descr - Reinitialize RX descriptor
   * @card: card structure
   * @descr: descriptor to re-init
   *
   * Return 0 on success, <0 on failure.
   *
   * Allocates a new rx skb, iommu-maps it and attaches it to the
   * descriptor. Mark the descriptor as activated, ready-to-use.
   */
  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 = dma_map_single(&card->pdev->dev, descr->skb->data,
  			     SPIDER_NET_MAX_FRAME, DMA_FROM_DEVICE);
  	if (dma_mapping_error(&card->pdev->dev, 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;
  }
  
  /**
   * spider_net_enable_rxchtails - sets RX dmac chain tail addresses
   * @card: card structure
   *
   * spider_net_enable_rxchtails sets the RX DMAC chain tail addresses in the
   * chip by writing to the appropriate register. DMA is enabled in
   * spider_net_enable_rxdmac.
   */
  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);
  }
  
  /**
   * spider_net_enable_rxdmac - enables a receive DMA controller
   * @card: card structure
   *
   * spider_net_enable_rxdmac enables the DMA controller by setting RX_DMA_EN
   * in the GDADMACCNTR register
   */
  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);
  }
  
  /**
   * spider_net_disable_rxdmac - disables the receive DMA controller
   * @card: card structure
   *
   * spider_net_disable_rxdmac terminates processing on the DMA controller
   * by turing off the DMA controller, with the force-end flag set.
   */
  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);
  }
  
  /**
   * spider_net_refill_rx_chain - refills descriptors/skbs in the rx chains
   * @card: card structure
   *
   * refills descriptors in the rx chain: allocates skbs and iommu-maps them.
   */
  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);
  }
  
  /**
   * spider_net_alloc_rx_skbs - Allocates rx skbs in rx descriptor chains
   * @card: card structure
   *
   * Returns 0 on success, <0 on failure.
   */
  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;
  }
  
  /**
   * spider_net_get_multicast_hash - generates hash for multicast filter table
   * @netdev: interface device structure
   * @addr: multicast address
   *
   * returns the hash value.
   *
   * spider_net_get_multicast_hash calculates a hash value for a given multicast
   * address, that is used to set the multicast filter tables
   */
  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;
  }
  
  /**
   * spider_net_set_multi - sets multicast addresses and promisc flags
   * @netdev: interface device structure
   *
   * spider_net_set_multi configures multicast addresses as needed for the
   * netdev interface. It also sets up multicast, allmulti and promisc
   * flags appropriately
   */
  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);
  	DECLARE_BITMAP(bitmask, SPIDER_NET_MULTICAST_HASHES) = {};
  
  	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);
  	}
  }
  
  /**
   * spider_net_prepare_tx_descr - fill tx descriptor with skb data
   * @card: card structure
   * @skb: packet to use
   *
   * returns 0 on success, <0 on failure.
   *
   * fills out the descriptor structure with skb data and len. Copies data,
   * if needed (32bit DMA!)
   */
  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 = dma_map_single(&card->pdev->dev, skb->data, skb->len,
  			     DMA_TO_DEVICE);
  	if (dma_mapping_error(&card->pdev->dev, 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);
  		dma_unmap_single(&card->pdev->dev, buf, skb->len,
  				 DMA_TO_DEVICE);
  		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;
  
  	netif_trans_update(card->netdev); /* 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;
  }
  
  /**
   * spider_net_release_tx_chain - processes sent tx descriptors
   * @card: adapter structure
   * @brutal: if set, don't care about whether descriptor seems to be in use
   *
   * returns 0 if the tx ring is empty, otherwise 1.
   *
   * spider_net_release_tx_chain releases the tx descriptors that spider has
   * finished with (if non-brutal) or simply release tx descriptors (if brutal).
   * If some other context is calling this function, we return 1 so that we're
   * scheduled again (if we were scheduled) and will not lose initiative.
   */
  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)
  			 */
  			fallthrough;
  
  		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) {
  			dma_unmap_single(&card->pdev->dev, buf_addr, skb->len,
  					 DMA_TO_DEVICE);
  			dev_consume_skb_any(skb);
  		}
  	}
  	return 0;
  }
  
  /**
   * spider_net_kick_tx_dma - enables TX DMA processing
   * @card: card structure
   *
   * This routine will start the transmit DMA running if
   * it is not already running. This routine ned only be
   * called when queueing a new packet to an empty tx queue.
   * Writes the current tx chain head as start address
   * of the tx descriptor chain and enables the transmission
   * DMA engine.
   */
  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);
  }
  
  /**
   * spider_net_xmit - transmits a frame over the device
   * @skb: packet to send out
   * @netdev: interface device structure
   *
   * returns NETDEV_TX_OK on success, NETDEV_TX_BUSY on failure
   */
  static netdev_tx_t
  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;
  }
  
  /**
   * spider_net_cleanup_tx_ring - cleans up the TX ring
   * @t: timer context used to obtain the pointer to net card data structure
   *
   * spider_net_cleanup_tx_ring is called by either the tx_timer
   * or from the NAPI polling routine.
   * This routine releases resources associted with transmitted
   * packets, including updating the queue tail pointer.
   */
  static void
  spider_net_cleanup_tx_ring(struct timer_list *t)
  {
  	struct spider_net_card *card = from_timer(card, t, tx_timer);
  	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);
  	}
  }
  
  /**
   * spider_net_do_ioctl - called for device ioctls
   * @netdev: interface device structure
   * @ifr: request parameter structure for ioctl
   * @cmd: command code for ioctl
   *
   * returns 0 on success, <0 on failure. Currently, we have no special ioctls.
   * -EOPNOTSUPP is returned, if an unknown ioctl was requested
   */
  static int
  spider_net_do_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
  {
  	switch (cmd) {
  	default:
  		return -EOPNOTSUPP;
  	}
  }
  
  /**
   * spider_net_pass_skb_up - takes an skb from a descriptor and passes it on
   * @descr: descriptor to process
   * @card: card structure
   *
   * Fills out skb structure and passes the data to the stack.
   * The descriptor state is not changed.
   */
  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
  
  }
  
  /**
   * spider_net_resync_head_ptr - Advance head ptr past empty descrs
   * @card: card structure
   *
   * If the driver fails to keep up and empty the queue, then the
   * hardware wil run out of room to put incoming packets. This
   * will cause the hardware to skip descrs that are full (instead
   * of halting/retrying). Thus, once the driver runs, it wil need
   * to "catch up" to where the hardware chain pointer is at.
   */
  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;
  }
  
  /**
   * spider_net_decode_one_descr - processes an RX descriptor
   * @card: card structure
   *
   * Returns 1 if a packet has been sent to the stack, otherwise 0.
   *
   * Processes an RX descriptor by iommu-unmapping the data buffer
   * and passing the packet up to the stack. This function is called
   * in softirq context, e.g. either bottom half from interrupt or
   * NAPI polling context.
   */
  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;
  	dma_unmap_single(&card->pdev->dev, hw_buf_addr, SPIDER_NET_MAX_FRAME,
  			 DMA_FROM_DEVICE);
  
  	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;
  }
  
  /**
   * spider_net_poll - NAPI poll function called by the stack to return packets
   * @napi: napi device structure
   * @budget: number of packets we can pass to the stack at most
   *
   * returns 0 if no more packets available to the driver/stack. Returns 1,
   * if the quota is exceeded, but the driver has still packets.
   *
   * spider_net_poll returns all packets from the rx descriptors to the stack
   * (using netif_receive_skb). If all/enough packets are up, the driver
   * reenables interrupts and returns 0. If not, 1 is returned.
   */
  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->tx_timer);
  
  	/* if all packets are in the stack, enable interrupts and return 0 */
  	/* if not, return 1 */
  	if (packets_done < budget) {
  		napi_complete_done(napi, packets_done);
  		spider_net_rx_irq_on(card);
  		card->ignore_rx_ramfull = 0;
  	}
  
  	return packets_done;
  }
  
  /**
   * spider_net_set_mac - sets the MAC of an interface
   * @netdev: interface device structure
   * @p: pointer to new MAC address
   *
   * Returns 0 on success, <0 on failure. Currently, we don't support this
   * and will always return EOPNOTSUPP.
   */
  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;
  
  	memcpy(netdev->dev_addr, addr->sa_data, ETH_ALEN);
  
  	/* 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 = (netdev->dev_addr[0]<<24) + (netdev->dev_addr[1]<<16) +
  		(netdev->dev_addr[2]<<8) + (netdev->dev_addr[3]);
  	macl = (netdev->dev_addr[4]<<8) + (netdev->dev_addr[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);
  
  	return 0;
  }
  
  /**
   * spider_net_link_reset
   * @netdev: net device structure
   *
   * This is called when the PHY_LINK signal is asserted. For the blade this is
   * not connected so we should never get here.
   *
   */
  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);
  
  }
  
  /**
   * spider_net_handle_error_irq - handles errors raised by an interrupt
   * @card: card structure
   * @status_reg: interrupt status register 0 (GHIINT0STS)
   * @error_reg1: interrupt status register 1 (GHIINT1STS)
   * @error_reg2: interrupt status register 2 (GHIINT2STS)
   *
   * spider_net_handle_error_irq treats or ignores all error conditions
   * found when an interrupt is presented
   */
  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:
  	case SPIDER_NET_GDCDEN0INT:
  	case SPIDER_NET_GDBDEN0INT:
  	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:
  	case SPIDER_NET_GRFCFLLINT:
  	case SPIDER_NET_GRFBFLLINT:
  	case SPIDER_NET_GRFAFLLINT:
  	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:
  	case SPIDER_NET_GDCDCEINT:
  	case SPIDER_NET_GDBDCEINT:
  	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:
  	case SPIDER_NET_GDCINVDINT:
  	case SPIDER_NET_GDBINVDINT:
  	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);
  }
  
  /**
   * spider_net_interrupt - interrupt handler for spider_net
   * @irq: interrupt number
   * @ptr: pointer to net_device
   *
   * returns IRQ_HANDLED, if interrupt was for driver, or IRQ_NONE, if no
   * interrupt found raised by card.
   *
   * This is the interrupt handler, that turns off
   * interrupts for this device and makes the stack poll the driver
   */
  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
  /**
   * spider_net_poll_controller - artificial interrupt for netconsole etc.
   * @netdev: interface device structure
   *
   * see Documentation/networking/netconsole.rst
   */
  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 */
  
  /**
   * spider_net_enable_interrupts - enable interrupts
   * @card: card structure
   *
   * spider_net_enable_interrupt enables several interrupts
   */
  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);
  }
  
  /**
   * spider_net_disable_interrupts - disable interrupts
   * @card: card structure
   *
   * spider_net_disable_interrupts disables all the interrupts
   */
  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);
  }
  
  /**
   * spider_net_init_card - initializes the card
   * @card: card structure
   *
   * spider_net_init_card initializes the card so that other registers can
   * be used
   */
  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);
  }
  
  /**
   * spider_net_enable_card - enables the card by setting all kinds of regs
   * @card: card structure
   *
   * spider_net_enable_card sets a lot of SMMIO registers to enable the device
   */
  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);
  }
  
  /**
   * spider_net_download_firmware - loads firmware into the adapter
   * @card: card structure
   * @firmware_ptr: pointer to firmware data
   *
   * spider_net_download_firmware loads the firmware data into the
   * adapter. It assumes the length etc. to be allright.
   */
  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;
  }
  
  /**
   * spider_net_init_firmware - reads in firmware parts
   * @card: card structure
   *
   * Returns 0 on success, <0 on failure
   *
   * spider_net_init_firmware opens the sequencer firmware and does some basic
   * checks. This function opens and releases the firmware structure. A call
   * to download the firmware is performed before the release.
   *
   * Firmware format
   * ===============
   * spider_fw.bin is expected to be a file containing 6*1024*4 bytes, 4k being
   * the program for each sequencer. Use the command
   *    tail -q -n +2 Seq_code1_0x088.txt Seq_code2_0x090.txt              \
   *         Seq_code3_0x098.txt Seq_code4_0x0A0.txt Seq_code5_0x0A8.txt   \
   *         Seq_code6_0x0B0.txt | xxd -r -p -c4 > spider_fw.bin
   *
   * to generate spider_fw.bin, if you have sequencer programs with something
   * like the following contents for each sequencer:
   *    <ONE LINE COMMENT>
   *    <FIRST 4-BYTES-WORD FOR SEQUENCER>
   *    <SECOND 4-BYTES-WORD FOR SEQUENCER>
   *     ...
   *    <1024th 4-BYTES-WORD FOR SEQUENCER>
   */
  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;
  }
  
  /**
   * spider_net_open - called upon ifonfig up
   * @netdev: interface device structure
   *
   * returns 0 on success, <0 on failure
   *
   * spider_net_open allocates all the descriptors and memory needed for
   * operation, sets up multicast list and enables interrupts
   */
  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 */
  	result = spider_net_alloc_rx_skbs(card);
  	if (result)
  		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;
  }
  
  /**
   * spider_net_link_phy
   * @t: timer context used to obtain the pointer to net card data structure
   */
  static void spider_net_link_phy(struct timer_list *t)
  {
  	struct spider_net_card *card = from_timer(card, t, aneg_timer);
  	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 ");
  }
  
  /**
   * spider_net_setup_phy - setup PHY
   * @card: card structure
   *
   * returns 0 on success, <0 on failure
   *
   * spider_net_setup_phy is used as part of spider_net_probe.
   **/
  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;
  }
  
  /**
   * spider_net_workaround_rxramfull - work around firmware bug
   * @card: card structure
   *
   * no return value
   **/
  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);
  }
  
  /**
   * spider_net_stop - called upon ifconfig down
   * @netdev: interface device structure
   *
   * always returns 0
   */
  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;
  }
  
  /**
   * spider_net_tx_timeout_task - task scheduled by the watchdog timeout
   * function (to be called not under interrupt status)
   * @work: work context used to obtain the pointer to net card data structure
   *
   * called as task when tx hangs, resets interface (if interface is up)
   */
  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);
  }
  
  /**
   * spider_net_tx_timeout - called when the tx timeout watchdog kicks in.
   * @netdev: interface device structure
   * @txqueue: unused
   *
   * called, if tx hangs. Schedules a task that resets the interface
   */
  static void
  spider_net_tx_timeout(struct net_device *netdev, unsigned int txqueue)
  {
  	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_eth_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 */
  };
  
  /**
   * spider_net_setup_netdev_ops - initialization of net_device operations
   * @netdev: net_device structure
   *
   * fills out function pointers in the net_device structure
   */
  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;
  }
  
  /**
   * spider_net_setup_netdev - initialization of net_device
   * @card: card structure
   *
   * Returns 0 on success or <0 on failure
   *
   * spider_net_setup_netdev initializes the net_device structure
   **/
  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);
  
  	timer_setup(&card->tx_timer, spider_net_cleanup_tx_ring, 0);
  	netdev->irq = card->pdev->irq;
  
  	card->aneg_count = 0;
  	timer_setup(&card->aneg_timer, spider_net_link_phy, 0);
  
  	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_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX |
  	 *		NETIF_F_HW_VLAN_CTAG_FILTER
  	 */
  
  	/* MTU range: 64 - 2294 */
  	netdev->min_mtu = SPIDER_NET_MIN_MTU;
  	netdev->max_mtu = SPIDER_NET_MAX_MTU;
  
  	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;
  }
  
  /**
   * spider_net_alloc_card - allocates net_device and card structure
   *
   * returns the card structure or NULL in case of errors
   *
   * the card and net_device structures are linked to each other
   */
  static struct spider_net_card *
  spider_net_alloc_card(void)
  {
  	struct net_device *netdev;
  	struct spider_net_card *card;
  
  	netdev = alloc_etherdev(struct_size(card, darray,
  					    tx_descriptors + rx_descriptors));
  	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;
  }
  
  /**
   * spider_net_undo_pci_setup - releases PCI ressources
   * @card: card structure
   *
   * spider_net_undo_pci_setup releases the mapped regions
   */
  static void
  spider_net_undo_pci_setup(struct spider_net_card *card)
  {
  	iounmap(card->regs);
  	pci_release_regions(card->pdev);
  }
  
  /**
   * spider_net_setup_pci_dev - sets up the device in terms of PCI operations
   * @pdev: PCI device
   *
   * Returns the card structure or NULL if any errors occur
   *
   * spider_net_setup_pci_dev initializes pdev and together with the
   * functions called in spider_net_open configures the device so that
   * data can be transferred over it
   * The net_device structure is attached to the card structure, if the
   * function returns without error.
   **/
  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);
  	return NULL;
  }
  
  /**
   * spider_net_probe - initialization of a device
   * @pdev: PCI device
   * @ent: entry in the device id list
   *
   * Returns 0 on success, <0 on failure
   *
   * spider_net_probe initializes pdev and registers a net_device
   * structure for it. After that, the device can be ifconfig'ed up
   **/
  static int
  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;
  }
  
  /**
   * spider_net_remove - removal of a device
   * @pdev: PCI device
   *
   * Returns 0 on success, <0 on failure
   *
   * spider_net_remove is called to remove the device and unregisters the
   * net_device
   **/
  static void
  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		= spider_net_remove
  };
  
  /**
   * spider_net_init - init function when the driver is loaded
   *
   * spider_net_init registers the device driver
   */
  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);
  }
  
  /**
   * spider_net_cleanup - exit function when driver is unloaded
   *
   * spider_net_cleanup unregisters the device driver
   */
  static void __exit spider_net_cleanup(void)
  {
  	pci_unregister_driver(&spider_net_driver);
  }
  
  module_init(spider_net_init);
  module_exit(spider_net_cleanup);
  