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/* epic100.c: A SMC 83c170 EPIC/100 Fast Ethernet driver for Linux. */
/*
	Written/copyright 1997-2000 by Donald Becker.

	This software may be used and distributed according to the terms of
	the GNU General Public License (GPL), incorporated herein by reference.
	Drivers based on or derived from this code fall under the GPL and must
	retain the authorship, copyright and license notice.  This file is not
	a complete program and may only be used when the entire operating
	system is licensed under the GPL.

	This driver is for the SMC83c170/175 "EPIC" series, as used on the
	SMC EtherPower II 9432 PCI adapter, and several CardBus cards.

	The author may be reached as becker@scyld.com, or C/O
	Scyld Computing Corporation
	410 Severn Ave., Suite 210
	Annapolis MD 21403

	Information and updates available at
	http://www.scyld.com/network/epic100.html

	---------------------------------------------------------------------
	
	Linux kernel-specific changes:
	
	LK1.1.2 (jgarzik):
	* Merge becker version 1.09 (4/08/2000)

	LK1.1.3:
	* Major bugfix to 1.09 driver (Francis Romieu)
	
	LK1.1.4 (jgarzik):
	* Merge becker test version 1.09 (5/29/2000)

	LK1.1.5:
	* Fix locking (jgarzik)
	* Limit 83c175 probe to ethernet-class PCI devices (rgooch)

*/

/* These identify the driver base version and may not be removed. */
static const char version[] =
"epic100.c:v1.09 5/29/2000 Written by Donald Becker <becker@scyld.com>\n";
static const char version2[] =
"  http://www.scyld.com/network/epic100.html\n";
static const char version3[] =
" (unofficial 2.4.x kernel port, version 1.1.5, September 7, 2000)\n";

/* The user-configurable values.
   These may be modified when a driver module is loaded.*/

static int debug = 1;			/* 1 normal messages, 0 quiet .. 7 verbose. */
/* Maximum events (Rx packets, etc.) to handle at each interrupt. */
static int max_interrupt_work = 32;

/* Used to pass the full-duplex flag, etc. */
#define MAX_UNITS 8		/* More are supported, limit only on options */
static int options[MAX_UNITS] = {-1, -1, -1, -1, -1, -1, -1, -1};
static int full_duplex[MAX_UNITS] = {-1, -1, -1, -1, -1, -1, -1, -1};

/* Set the copy breakpoint for the copy-only-tiny-frames scheme.
   Setting to > 1518 effectively disables this feature. */
static int rx_copybreak = 0;

/* Operational parameters that are set at compile time. */

/* Keep the ring sizes a power of two for operational efficiency.
   The compiler will convert <unsigned>'%'<2^N> into a bit mask.
   Making the Tx ring too large decreases the effectiveness of channel
   bonding and packet priority.
   There are no ill effects from too-large receive rings. */
#define TX_RING_SIZE	16
#define TX_QUEUE_LEN	10		/* Limit ring entries actually used.  */
#define RX_RING_SIZE	32

/* Operational parameters that usually are not changed. */
/* Time in jiffies before concluding the transmitter is hung. */
#define TX_TIMEOUT  (2*HZ)

#define PKT_BUF_SZ		1536			/* Size of each temporary Rx buffer.*/

/* Bytes transferred to chip before transmission starts. */
/* Initial threshold, increased on underflow, rounded down to 4 byte units. */
#define TX_FIFO_THRESH 256
#define RX_FIFO_THRESH 1		/* 0-3, 0==32, 64,96, or 3==128 bytes  */

#if !defined(__OPTIMIZE__)
#warning  You must compile this file with the correct options!
#warning  See the last lines of the source file.
#error You must compile this driver with "-O".
#endif

#include <linux/version.h>
#include <linux/module.h>
#if LINUX_VERSION_CODE < 0x20300  &&  defined(MODVERSIONS)
#include <linux/modversions.h>
#endif

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/malloc.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <asm/bitops.h>
#include <asm/io.h>

MODULE_AUTHOR("Donald Becker <becker@scyld.com>");
MODULE_DESCRIPTION("SMC 83c170 EPIC series Ethernet driver");
MODULE_PARM(debug, "i");
MODULE_PARM(max_interrupt_work, "i");
MODULE_PARM(rx_copybreak, "i");
MODULE_PARM(options, "1-" __MODULE_STRING(MAX_UNITS) "i");
MODULE_PARM(full_duplex, "1-" __MODULE_STRING(MAX_UNITS) "i");

/*
				Theory of Operation

I. Board Compatibility

This device driver is designed for the SMC "EPIC/100", the SMC
single-chip Ethernet controllers for PCI.  This chip is used on
the SMC EtherPower II boards.

II. Board-specific settings

PCI bus devices are configured by the system at boot time, so no jumpers
need to be set on the board.  The system BIOS will assign the
PCI INTA signal to a (preferably otherwise unused) system IRQ line.
Note: Kernel versions earlier than 1.3.73 do not support shared PCI
interrupt lines.

III. Driver operation

IIIa. Ring buffers

IVb. References

http://www.smsc.com/main/datasheets/83c171.pdf
http://www.smsc.com/main/datasheets/83c175.pdf
http://scyld.com/expert/NWay.html
http://www.national.com/pf/DP/DP83840A.html

IVc. Errata

*/


enum pci_id_flags_bits {
        /* Set PCI command register bits before calling probe1(). */
        PCI_USES_IO=1, PCI_USES_MEM=2, PCI_USES_MASTER=4,
        /* Read and map the single following PCI BAR. */
        PCI_ADDR0=0<<4, PCI_ADDR1=1<<4, PCI_ADDR2=2<<4, PCI_ADDR3=3<<4,
        PCI_ADDR_64BITS=0x100, PCI_NO_ACPI_WAKE=0x200, PCI_NO_MIN_LATENCY=0x400,
};

enum chip_capability_flags { MII_PWRDWN=1, TYPE2_INTR=2, NO_MII=4 };

#define EPIC_TOTAL_SIZE 0x100
#ifdef USE_IO_OPS
#define EPIC_IOTYPE PCI_USES_MASTER|PCI_USES_IO|PCI_ADDR0
#else
#define EPIC_IOTYPE PCI_USES_MASTER|PCI_USES_MEM|PCI_ADDR1
#endif

#define virt_to_le32desc(addr)  cpu_to_le32(virt_to_bus(addr))

typedef enum {
	SMSC_83C170_0,
	SMSC_83C170,
	SMSC_83C175,
} chip_t;


struct epic_chip_info {
	const char *name;
	enum pci_id_flags_bits pci_flags;
        int io_size;                            /* Needed for I/O region check or ioremap(). */
        int drv_flags;                          /* Driver use, intended as capability flags. */
};


/* indexed by chip_t */
static struct epic_chip_info epic_chip_info[] __devinitdata = {
	{ "SMSC EPIC/100 83c170",
	 EPIC_IOTYPE, EPIC_TOTAL_SIZE, TYPE2_INTR | NO_MII | MII_PWRDWN },
	{ "SMSC EPIC/100 83c170",
	 EPIC_IOTYPE, EPIC_TOTAL_SIZE, TYPE2_INTR },
	{ "SMSC EPIC/C 83c175",
	 EPIC_IOTYPE, EPIC_TOTAL_SIZE, TYPE2_INTR | MII_PWRDWN },
};


static struct pci_device_id epic_pci_tbl[] __devinitdata = {
	{ 0x10B8, 0x0005, 0x1092, 0x0AB4, 0, 0, SMSC_83C170_0 },
	{ 0x10B8, 0x0005, PCI_ANY_ID, PCI_ANY_ID, 0, 0, SMSC_83C170 },
	{ 0x10B8, 0x0006, PCI_ANY_ID, PCI_ANY_ID,
	  PCI_CLASS_NETWORK_ETHERNET << 8, 0xffff00, SMSC_83C175 },
	{ 0,}
};
MODULE_DEVICE_TABLE (pci, epic_pci_tbl);

	
#ifndef USE_IO_OPS
#undef inb
#undef inw
#undef inl
#undef outb
#undef outw
#undef outl
#define inb readb
#define inw readw
#define inl readl
#define outb writeb
#define outw writew
#define outl writel
#endif

/* Offsets to registers, using the (ugh) SMC names. */
enum epic_registers {
  COMMAND=0, INTSTAT=4, INTMASK=8, GENCTL=0x0C, NVCTL=0x10, EECTL=0x14,
  PCIBurstCnt=0x18,
  TEST1=0x1C, CRCCNT=0x20, ALICNT=0x24, MPCNT=0x28,	/* Rx error counters. */
  MIICtrl=0x30, MIIData=0x34, MIICfg=0x38,
  LAN0=64,						/* MAC address. */
  MC0=80,						/* Multicast filter table. */
  RxCtrl=96, TxCtrl=112, TxSTAT=0x74,
  PRxCDAR=0x84, RxSTAT=0xA4, EarlyRx=0xB0, PTxCDAR=0xC4, TxThresh=0xDC,
};

/* Interrupt register bits, using my own meaningful names. */
enum IntrStatus {
	TxIdle=0x40000, RxIdle=0x20000, IntrSummary=0x010000,
	PCIBusErr170=0x7000, PCIBusErr175=0x1000, PhyEvent175=0x8000,
	RxStarted=0x0800, RxEarlyWarn=0x0400, CntFull=0x0200, TxUnderrun=0x0100,
	TxEmpty=0x0080, TxDone=0x0020, RxError=0x0010,
	RxOverflow=0x0008, RxFull=0x0004, RxHeader=0x0002, RxDone=0x0001,
};
enum CommandBits {
	StopRx=1, StartRx=2, TxQueued=4, RxQueued=8,
	StopTxDMA=0x20, StopRxDMA=0x40, RestartTx=0x80,
};

static u16 media2miictl[16] = {
	0, 0x0C00, 0x0C00, 0x2000,  0x0100, 0x2100, 0, 0,
	0, 0, 0, 0,  0, 0, 0, 0 };

/* The EPIC100 Rx and Tx buffer descriptors. */

struct epic_tx_desc {
	u32 txstatus;
	u32 bufaddr;
	u32 buflength;
	u32 next;
};

struct epic_rx_desc {
	u32 rxstatus;
	u32 bufaddr;
	u32 buflength;
	u32 next;
};

enum desc_status_bits {
	DescOwn=0x8000,
};


struct epic_private {
	/* Tx and Rx rings first so that they remain paragraph aligned. */
	struct epic_rx_desc rx_ring[RX_RING_SIZE];
	struct epic_tx_desc tx_ring[TX_RING_SIZE];
	/* The saved address of a sent-in-place packet/buffer, for skfree(). */
	struct sk_buff* tx_skbuff[TX_RING_SIZE];
	/* The addresses of receive-in-place skbuffs. */
	struct sk_buff* rx_skbuff[RX_RING_SIZE];

	/* Ring pointers. */
	spinlock_t lock;				/* Group with Tx control cache line. */
	unsigned int cur_tx, dirty_tx;
	struct descriptor  *last_tx_desc;

	unsigned int cur_rx, dirty_rx;
	unsigned int rx_buf_sz;				/* Based on MTU+slack. */
	struct descriptor  *last_rx_desc;
	long last_rx_time;					/* Last Rx, in jiffies. */

	struct pci_dev *pci_dev;			/* PCI bus location. */
	int chip_flags;

	struct net_device_stats stats;
	struct timer_list timer;			/* Media selection timer. */
	int tx_threshold;
	unsigned char mc_filter[8];
	signed char phys[4];				/* MII device addresses. */
	u16 advertising;					/* NWay media advertisement */
	int mii_phy_cnt;
	unsigned int tx_full:1;				/* The Tx queue is full. */
	unsigned int full_duplex:1;			/* Current duplex setting. */
	unsigned int force_fd:1;			/* Full-duplex operation requested. */
	unsigned int default_port:4;		/* Last dev->if_port value. */
	unsigned int media2:4;				/* Secondary monitored media port. */
	unsigned int medialock:1;			/* Don't sense media type. */
	unsigned int mediasense:1;			/* Media sensing in progress. */
};

static int epic_open(struct net_device *dev);
static int read_eeprom(long ioaddr, int location);
static int mdio_read(long ioaddr, int phy_id, int location);
static void mdio_write(long ioaddr, int phy_id, int location, int value);
static void epic_restart(struct net_device *dev);
static void epic_timer(unsigned long data);
static void epic_tx_timeout(struct net_device *dev);
static void epic_init_ring(struct net_device *dev);
static int epic_start_xmit(struct sk_buff *skb, struct net_device *dev);
static int epic_rx(struct net_device *dev);
static void epic_interrupt(int irq, void *dev_instance, struct pt_regs *regs);
static int mii_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
static int epic_close(struct net_device *dev);
static struct net_device_stats *epic_get_stats(struct net_device *dev);
static void set_rx_mode(struct net_device *dev);



static int __devinit epic_init_one (struct pci_dev *pdev,
				    const struct pci_device_id *ent)
{
	static int card_idx = -1;
	static int printed_version = 0;
	struct net_device *dev;
	struct epic_private *ep;
	int i, option = 0, duplex = 0;
	struct epic_chip_info *ci = &epic_chip_info[ent->driver_data];
	long ioaddr;
	int chip_idx = (int) ent->driver_data;

	card_idx++;
	
	if (!printed_version++)
		printk (KERN_INFO "%s" KERN_INFO "%s" KERN_INFO "%s",
			version, version2, version3);
	
	if ((pci_resource_len(pdev, 0) < ci->io_size) ||
	    (pci_resource_len(pdev, 1) < ci->io_size)) {
		printk (KERN_ERR "card %d: no PCI region space\n", card_idx);
		return -ENODEV;
	}
	
	i = pci_enable_device(pdev);
	if (i)
		return i;
		
	pci_set_master(pdev);

	dev = init_etherdev(NULL, sizeof (*ep));
	if (!dev) {
		printk (KERN_ERR "card %d: no memory for eth device\n", card_idx);
		return -ENOMEM;
	}

	/* request 100% of both regions 0 and 1, just to make
	 * sure noone else steals our regions while we are talking
	 * to them */
	if (!request_region (pci_resource_start (pdev, 0),
			     pci_resource_len (pdev, 0), dev->name)) {
		printk (KERN_ERR "epic100 %d: I/O region busy\n", card_idx);
		goto err_out_free_netdev;
	}
	if (!request_mem_region (pci_resource_start (pdev, 1),
				 pci_resource_len (pdev, 1), dev->name)) {
		printk (KERN_ERR "epic100 %d: I/O region busy\n", card_idx);
		goto err_out_free_pio;
	}

#ifdef USE_IO_OPS
	ioaddr = pci_resource_start (pdev, 0);
#else
	ioaddr = pci_resource_start (pdev, 1);
	ioaddr = (long) ioremap (ioaddr, pci_resource_len (pdev, 1));
	if (!ioaddr) {
		printk (KERN_ERR "epic100 %d: ioremap failed\n", card_idx);
		goto err_out_free_mmio;
	}
#endif

	if (dev->mem_start) {
		option = dev->mem_start;
		duplex = (dev->mem_start & 16) ? 1 : 0;
	} else if (card_idx >= 0  &&  card_idx < MAX_UNITS) {
		if (options[card_idx] >= 0)
			option = options[card_idx];
		if (full_duplex[card_idx] >= 0)
			duplex = full_duplex[card_idx];
	}

	pdev->driver_data = dev;

	dev->base_addr = ioaddr;
	dev->irq = pdev->irq;

	ep = dev->priv;
	ep->pci_dev = pdev;
	ep->chip_flags = ci->drv_flags;
	spin_lock_init (&ep->lock);

	printk(KERN_INFO "%s: %s at %#lx, IRQ %d, ",
		   dev->name, ci->name, ioaddr, dev->irq);

	/* Bring the chip out of low-power mode. */
	outl(0x4200, ioaddr + GENCTL);
	/* Magic?!  If we don't set this bit the MII interface won't work. */
	outl(0x0008, ioaddr + TEST1);

	/* Turn on the MII transceiver. */
	outl(0x12, ioaddr + MIICfg);
	if (chip_idx == 1)
		outl((inl(ioaddr + NVCTL) & ~0x003C) | 0x4800, ioaddr + NVCTL);
	outl(0x0200, ioaddr + GENCTL);

	/* This could also be read from the EEPROM. */
	for (i = 0; i < 3; i++)
		((u16 *)dev->dev_addr)[i] = le16_to_cpu(inw(ioaddr + LAN0 + i*4));

	for (i = 0; i < 5; i++)
		printk("%2.2x:", dev->dev_addr[i]);
	printk("%2.2x.\n", dev->dev_addr[i]);

	if (debug > 2) {
		printk(KERN_DEBUG "%s: EEPROM contents\n", dev->name);
		for (i = 0; i < 64; i++)
			printk(" %4.4x%s", read_eeprom(ioaddr, i),
				   i % 16 == 15 ? "\n" : "");
	}

	/* Find the connected MII xcvrs.
	   Doing this in open() would allow detecting external xcvrs later, but
	   takes much time and no cards have external MII. */
	{
		int phy, phy_idx = 0;
		for (phy = 1; phy < 32 && phy_idx < sizeof(ep->phys); phy++) {
			int mii_status = mdio_read(ioaddr, phy, 1);
			if (mii_status != 0xffff  &&  mii_status != 0x0000) {
				ep->phys[phy_idx++] = phy;
				printk(KERN_INFO "%s: MII transceiver #%d control "
					   "%4.4x status %4.4x.\n",
					   dev->name, phy, mdio_read(ioaddr, phy, 0), mii_status);
			}
		}
		ep->mii_phy_cnt = phy_idx;
		if (phy_idx != 0) {
			phy = ep->phys[0];
			ep->advertising = mdio_read(ioaddr, phy, 4);
			printk( KERN_INFO "%s: Autonegotiation advertising %4.4x link "
					"partner %4.4x.\n",
					dev->name, ep->advertising, mdio_read(ioaddr, phy, 5));
		} else if ( ! (ep->chip_flags & NO_MII)) {
			printk(KERN_WARNING "%s: ***WARNING***: No MII transceiver found!\n",
				   dev->name);
			/* Use the known PHY address of the EPII. */
			ep->phys[0] = 3;
		}
	}

	/* Turn off the MII xcvr (175 only!), leave the chip in low-power mode. */
	if (ep->chip_flags & MII_PWRDWN)
		outl(inl(ioaddr + NVCTL) & ~0x483C, ioaddr + NVCTL);
	outl(0x0008, ioaddr + GENCTL);

	/* The lower four bits are the media type. */
	ep->force_fd = duplex;
	dev->if_port = ep->default_port = option;
	if (ep->default_port)
		ep->medialock = 1;

	/* The Epic-specific entries in the device structure. */
	dev->open = &epic_open;
	dev->hard_start_xmit = &epic_start_xmit;
	dev->stop = &epic_close;
	dev->get_stats = &epic_get_stats;
	dev->set_multicast_list = &set_rx_mode;
	dev->do_ioctl = &mii_ioctl;
	dev->watchdog_timeo = TX_TIMEOUT;
	dev->tx_timeout = &epic_tx_timeout;

	return 0;

#ifndef USE_IO_OPS
err_out_free_mmio:
	release_mem_region (pci_resource_start (pdev, 1),
			    pci_resource_len (pdev, 1));
#endif
err_out_free_pio:
	release_region (pci_resource_start (pdev, 0),
			pci_resource_len (pdev, 0));
err_out_free_netdev:
	unregister_netdev(dev);
	kfree(dev);
	return -ENODEV;
}

/* Serial EEPROM section. */

/*  EEPROM_Ctrl bits. */
#define EE_SHIFT_CLK	0x04	/* EEPROM shift clock. */
#define EE_CS			0x02	/* EEPROM chip select. */
#define EE_DATA_WRITE	0x08	/* EEPROM chip data in. */
#define EE_WRITE_0		0x01
#define EE_WRITE_1		0x09
#define EE_DATA_READ	0x10	/* EEPROM chip data out. */
#define EE_ENB			(0x0001 | EE_CS)

/* Delay between EEPROM clock transitions.
   No extra delay is needed with 33Mhz PCI, but 66Mhz is untested.
 */

#define eeprom_delay()	inl(ee_addr)

/* The EEPROM commands include the alway-set leading bit. */
#define EE_WRITE_CMD	(5 << 6)
#define EE_READ64_CMD	(6 << 6)
#define EE_READ256_CMD	(6 << 8)
#define EE_ERASE_CMD	(7 << 6)

static int read_eeprom(long ioaddr, int location)
{
	int i;
	int retval = 0;
	long ee_addr = ioaddr + EECTL;
	int read_cmd = location |
		(inl(ee_addr) & 0x40 ? EE_READ64_CMD : EE_READ256_CMD);

	outl(EE_ENB & ~EE_CS, ee_addr);
	outl(EE_ENB, ee_addr);

	/* Shift the read command bits out. */
	for (i = 12; i >= 0; i--) {
		short dataval = (read_cmd & (1 << i)) ? EE_WRITE_1 : EE_WRITE_0;
		outl(EE_ENB | dataval, ee_addr);
		eeprom_delay();
		outl(EE_ENB | dataval | EE_SHIFT_CLK, ee_addr);
		eeprom_delay();
	}
	outl(EE_ENB, ee_addr);

	for (i = 16; i > 0; i--) {
		outl(EE_ENB | EE_SHIFT_CLK, ee_addr);
		eeprom_delay();
		retval = (retval << 1) | ((inl(ee_addr) & EE_DATA_READ) ? 1 : 0);
		outl(EE_ENB, ee_addr);
		eeprom_delay();
	}

	/* Terminate the EEPROM access. */
	outl(EE_ENB & ~EE_CS, ee_addr);
	return retval;
}

#define MII_READOP		1
#define MII_WRITEOP		2
static int mdio_read(long ioaddr, int phy_id, int location)
{
	int i;

	outl((phy_id << 9) | (location << 4) | MII_READOP, ioaddr + MIICtrl);
	/* Typical operation takes < 50 ticks. */
	for (i = 4000; i > 0; i--)
		if ((inl(ioaddr + MIICtrl) & MII_READOP) == 0)
			return inw(ioaddr + MIIData);
	return 0xffff;
}

static void mdio_write(long ioaddr, int phy_id, int location, int value)
{
	int i;

	outw(value, ioaddr + MIIData);
	outl((phy_id << 9) | (location << 4) | MII_WRITEOP, ioaddr + MIICtrl);
	for (i = 10000; i > 0; i--) {
		if ((inl(ioaddr + MIICtrl) & MII_WRITEOP) == 0)
			break;
	}
	return;
}


static int epic_open(struct net_device *dev)
{
	struct epic_private *ep = (struct epic_private *)dev->priv;
	long ioaddr = dev->base_addr;
	int i;
	int retval;

	ep->full_duplex = ep->force_fd;

	/* Soft reset the chip. */
	outl(0x4001, ioaddr + GENCTL);

	MOD_INC_USE_COUNT;

	if ((retval = request_irq(dev->irq, &epic_interrupt, SA_SHIRQ, dev->name, dev))) {
		MOD_DEC_USE_COUNT;
		return retval;
	}

	epic_init_ring(dev);

	outl(0x4000, ioaddr + GENCTL);
	/* This next magic! line by Ken Yamaguchi.. ?? */
	outl(0x0008, ioaddr + TEST1);

	/* Pull the chip out of low-power mode, enable interrupts, and set for
	   PCI read multiple.  The MIIcfg setting and strange write order are
	   required by the details of which bits are reset and the transceiver
	   wiring on the Ositech CardBus card.
	*/
	outl(0x12, ioaddr + MIICfg);
	if (ep->chip_flags & MII_PWRDWN)
		outl((inl(ioaddr + NVCTL) & ~0x003C) | 0x4800, ioaddr + NVCTL);

#if defined(__powerpc__) || defined(__sparc__)		/* Big endian */
	outl(0x4432 | (RX_FIFO_THRESH<<8), ioaddr + GENCTL);
	inl(ioaddr + GENCTL);
	outl(0x0432 | (RX_FIFO_THRESH<<8), ioaddr + GENCTL);
#else
	outl(0x4412 | (RX_FIFO_THRESH<<8), ioaddr + GENCTL);
	inl(ioaddr + GENCTL);
	outl(0x0412 | (RX_FIFO_THRESH<<8), ioaddr + GENCTL);
#endif

	for (i = 0; i < 3; i++)
		outl(cpu_to_le16(((u16*)dev->dev_addr)[i]), ioaddr + LAN0 + i*4);

	ep->tx_threshold = TX_FIFO_THRESH;
	outl(ep->tx_threshold, ioaddr + TxThresh);

	if (media2miictl[dev->if_port & 15]) {
		if (ep->mii_phy_cnt)
			mdio_write(ioaddr, ep->phys[0], 0, media2miictl[dev->if_port&15]);
		if (dev->if_port == 1) {
			if (debug > 1)
				printk(KERN_INFO "%s: Using the 10base2 transceiver, MII "
					   "status %4.4x.\n",
					   dev->name, mdio_read(ioaddr, ep->phys[0], 1));
			outl(0x13, ioaddr + MIICfg);
		}
	} else {
		int mii_reg5 = mdio_read(ioaddr, ep->phys[0], 5);
		if (mii_reg5 != 0xffff) {
			if ((mii_reg5 & 0x0100) || (mii_reg5 & 0x01C0) == 0x0040)
				ep->full_duplex = 1;
			else if (! (mii_reg5 & 0x4000))
				mdio_write(ioaddr, ep->phys[0], 0, 0x1200);
			if (debug > 1)
				printk(KERN_INFO "%s: Setting %s-duplex based on MII xcvr %d"
					   " register read of %4.4x.\n", dev->name,
					   ep->full_duplex ? "full" : "half",
					   ep->phys[0], mii_reg5);
		}
	}

	outl(ep->full_duplex ? 0x7F : 0x79, ioaddr + TxCtrl);
	outl(virt_to_bus(ep->rx_ring), ioaddr + PRxCDAR);
	outl(virt_to_bus(ep->tx_ring), ioaddr + PTxCDAR);

	/* Start the chip's Rx process. */
	set_rx_mode(dev);
	outl(StartRx | RxQueued, ioaddr + COMMAND);

	netif_start_queue(dev);

	/* Enable interrupts by setting the interrupt mask. */
	outl((ep->chip_flags & TYPE2_INTR ? PCIBusErr175 : PCIBusErr170)
		 | CntFull | TxUnderrun | TxDone | TxEmpty
		 | RxError | RxOverflow | RxFull | RxHeader | RxDone,
		 ioaddr + INTMASK);

	if (debug > 1)
		printk(KERN_DEBUG "%s: epic_open() ioaddr %lx IRQ %d status %4.4x "
			   "%s-duplex.\n",
			   dev->name, ioaddr, dev->irq, (int)inl(ioaddr + GENCTL),
			   ep->full_duplex ? "full" : "half");

	/* Set the timer to switch to check for link beat and perhaps switch
	   to an alternate media type. */
	init_timer(&ep->timer);
	ep->timer.expires = jiffies + 3*HZ;
	ep->timer.data = (unsigned long)dev;
	ep->timer.function = &epic_timer;				/* timer handler */
	add_timer(&ep->timer);

	return 0;
}

/* Reset the chip to recover from a PCI transaction error.
   This may occur at interrupt time. */
static void epic_pause(struct net_device *dev)
{
	long ioaddr = dev->base_addr;
	struct epic_private *ep = (struct epic_private *)dev->priv;

	netif_stop_queue (dev);
	
	/* Disable interrupts by clearing the interrupt mask. */
	outl(0x00000000, ioaddr + INTMASK);
	/* Stop the chip's Tx and Rx DMA processes. */
	outw(StopRx | StopTxDMA | StopRxDMA, ioaddr + COMMAND);

	/* Update the error counts. */
	if (inw(ioaddr + COMMAND) != 0xffff) {
		ep->stats.rx_missed_errors += inb(ioaddr + MPCNT);
		ep->stats.rx_frame_errors += inb(ioaddr + ALICNT);
		ep->stats.rx_crc_errors += inb(ioaddr + CRCCNT);
	}

	/* Remove the packets on the Rx queue. */
	epic_rx(dev);
}

static void epic_restart(struct net_device *dev)
{
	long ioaddr = dev->base_addr;
	struct epic_private *ep = (struct epic_private *)dev->priv;
	int i;

	printk(KERN_DEBUG "%s: Restarting the EPIC chip, Rx %d/%d Tx %d/%d.\n",
		   dev->name, ep->cur_rx, ep->dirty_rx, ep->dirty_tx, ep->cur_tx);
	/* Soft reset the chip. */
	outl(0x0001, ioaddr + GENCTL);

	udelay(1);
	/* Duplicate code from epic_open(). */
	outl(0x0008, ioaddr + TEST1);

#if defined(__powerpc__) || defined(__sparc__)		/* Big endian */
	outl(0x0432 | (RX_FIFO_THRESH<<8), ioaddr + GENCTL);
#else
	outl(0x0412 | (RX_FIFO_THRESH<<8), ioaddr + GENCTL);
#endif
	outl(dev->if_port == 1 ? 0x13 : 0x12, ioaddr + MIICfg);
	if (ep->chip_flags & MII_PWRDWN)
		outl((inl(ioaddr + NVCTL) & ~0x003C) | 0x4800, ioaddr + NVCTL);

	for (i = 0; i < 3; i++)
		outl(cpu_to_le16(((u16*)dev->dev_addr)[i]), ioaddr + LAN0 + i*4);

	ep->tx_threshold = TX_FIFO_THRESH;
	outl(ep->tx_threshold, ioaddr + TxThresh);
	outl(ep->full_duplex ? 0x7F : 0x79, ioaddr + TxCtrl);
	outl(virt_to_bus(&ep->rx_ring[ep->cur_rx%RX_RING_SIZE]), ioaddr + PRxCDAR);
	outl(virt_to_bus(&ep->tx_ring[ep->dirty_tx%TX_RING_SIZE]),
		 ioaddr + PTxCDAR);

	/* Start the chip's Rx process. */
	set_rx_mode(dev);
	outl(StartRx | RxQueued, ioaddr + COMMAND);

	/* Enable interrupts by setting the interrupt mask. */
	outl((ep->chip_flags & TYPE2_INTR ? PCIBusErr175 : PCIBusErr170)
		 | CntFull | TxUnderrun | TxDone | TxEmpty
		 | RxError | RxOverflow | RxFull | RxHeader | RxDone,
		 ioaddr + INTMASK);
	printk(KERN_DEBUG "%s: epic_restart() done, cmd status %4.4x, ctl %4.4x"
		   " interrupt %4.4x.\n",
		   dev->name, (int)inl(ioaddr + COMMAND), (int)inl(ioaddr + GENCTL),
		   (int)inl(ioaddr + INTSTAT));
	return;
}

static void epic_timer(unsigned long data)
{
	struct net_device *dev = (struct net_device *)data;
	struct epic_private *ep = (struct epic_private *)dev->priv;
	long ioaddr = dev->base_addr;
	int next_tick = 60*HZ;
	int mii_reg5 = ep->mii_phy_cnt ? mdio_read(ioaddr, ep->phys[0], 5) : 0;
	int negotiated = mii_reg5 & ep->advertising;
	int duplex = (negotiated & 0x0100) || (negotiated & 0x01C0) == 0x0040;

	if (debug > 3) {
		printk(KERN_DEBUG "%s: Media monitor tick, Tx status %8.8x.\n",
			   dev->name, (int)inl(ioaddr + TxSTAT));
		printk(KERN_DEBUG "%s: Other registers are IntMask %4.4x "
			   "IntStatus %4.4x RxStatus %4.4x.\n",
			   dev->name, (int)inl(ioaddr + INTMASK),
			   (int)inl(ioaddr + INTSTAT), (int)inl(ioaddr + RxSTAT));
	}

	if (! ep->force_fd) {
		if (ep->full_duplex != duplex) {
			ep->full_duplex = duplex;
			printk(KERN_INFO "%s: Setting %s-duplex based on MII #%d link"
				   " partner capability of %4.4x.\n", dev->name,
				   ep->full_duplex ? "full" : "half", ep->phys[0], mii_reg5);
			outl(ep->full_duplex ? 0x7F : 0x79, ioaddr + TxCtrl);
		}
	}

	ep->timer.expires = jiffies + next_tick;
	add_timer(&ep->timer);
}

static void epic_tx_timeout(struct net_device *dev)
{
	struct epic_private *ep = (struct epic_private *)dev->priv;
	long ioaddr = dev->base_addr;

	if (debug > 0) {
		printk(KERN_WARNING "%s: Transmit timeout using MII device, "
			   "Tx status %4.4x.\n",
			   dev->name, (int)inw(ioaddr + TxSTAT));
		if (debug > 1) {
			printk(KERN_DEBUG "%s: Tx indices: dirty_tx %d, cur_tx %d.\n",
				   dev->name, ep->dirty_tx, ep->cur_tx);
		}
	}
	if (inw(ioaddr + TxSTAT) & 0x10) {		/* Tx FIFO underflow. */
		ep->stats.tx_fifo_errors++;
		outl(RestartTx, ioaddr + COMMAND);
	} else {
		epic_restart(dev);
		outl(TxQueued, dev->base_addr + COMMAND);
	}

	dev->trans_start = jiffies;
	ep->stats.tx_errors++;
	return;
}

/* Initialize the Rx and Tx rings, along with various 'dev' bits. */
static void epic_init_ring(struct net_device *dev)
{
	struct epic_private *ep = (struct epic_private *)dev->priv;
	int i;

	ep->tx_full = 0;
	ep->lock = (spinlock_t) SPIN_LOCK_UNLOCKED;
	ep->dirty_tx = ep->cur_tx = 0;
	ep->cur_rx = ep->dirty_rx = 0;
	ep->last_rx_time = jiffies;
	ep->rx_buf_sz = (dev->mtu <= 1500 ? PKT_BUF_SZ : dev->mtu + 32);

	/* Initialize all Rx descriptors. */
	for (i = 0; i < RX_RING_SIZE; i++) {
		ep->rx_ring[i].rxstatus = 0;
		ep->rx_ring[i].buflength = cpu_to_le32(ep->rx_buf_sz);
		ep->rx_ring[i].next = virt_to_le32desc(&ep->rx_ring[i+1]);
		ep->rx_skbuff[i] = 0;
	}
	/* Mark the last entry as wrapping the ring. */
	ep->rx_ring[i-1].next = virt_to_le32desc(&ep->rx_ring[0]);

	/* Fill in the Rx buffers.  Handle allocation failure gracefully. */
	for (i = 0; i < RX_RING_SIZE; i++) {
		struct sk_buff *skb = dev_alloc_skb(ep->rx_buf_sz);
		ep->rx_skbuff[i] = skb;
		if (skb == NULL)
			break;
		skb->dev = dev;			/* Mark as being used by this device. */
		skb_reserve(skb, 2);	/* 16 byte align the IP header. */
		ep->rx_ring[i].bufaddr = virt_to_le32desc(skb->tail);
		ep->rx_ring[i].rxstatus = cpu_to_le32(DescOwn);
	}
	ep->dirty_rx = (unsigned int)(i - RX_RING_SIZE);

	/* The Tx buffer descriptor is filled in as needed, but we
	   do need to clear the ownership bit. */
	for (i = 0; i < TX_RING_SIZE; i++) {
		ep->tx_skbuff[i] = 0;
		ep->tx_ring[i].txstatus = 0x0000;
		ep->tx_ring[i].next = virt_to_le32desc(&ep->tx_ring[i+1]);
	}
	ep->tx_ring[i-1].next = virt_to_le32desc(&ep->tx_ring[0]);
	return;
}

static int epic_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct epic_private *ep = (struct epic_private *)dev->priv;
	int entry, free_count;
	u32 ctrl_word;

	/* Caution: the write order is important here, set the field with the
	   "ownership" bit last. */
	spin_lock_irq(&ep->lock);

	/* Calculate the next Tx descriptor entry. */
	free_count = ep->cur_tx - ep->dirty_tx;
	entry = ep->cur_tx % TX_RING_SIZE;

	ep->tx_skbuff[entry] = skb;
	ep->tx_ring[entry].bufaddr = virt_to_le32desc(skb->data);

	if (free_count < TX_QUEUE_LEN/2) {/* Typical path */
		ctrl_word = cpu_to_le32(0x100000); /* No interrupt */
	} else if (free_count == TX_QUEUE_LEN/2) {
		ctrl_word = cpu_to_le32(0x140000); /* Tx-done intr. */
	} else if (free_count < TX_QUEUE_LEN - 1) {
		ctrl_word = cpu_to_le32(0x100000); /* No Tx-done intr. */
	} else {
		/* Leave room for an additional entry. */
		ctrl_word = cpu_to_le32(0x140000); /* Tx-done intr. */
		ep->tx_full = 1;
	}
	ep->tx_ring[entry].buflength = ctrl_word | cpu_to_le32(skb->len);
	ep->tx_ring[entry].txstatus =
		((skb->len >= ETH_ZLEN ? skb->len : ETH_ZLEN) << 16)
		| cpu_to_le32(DescOwn);

	ep->cur_tx++;
	if (ep->tx_full)
		netif_stop_queue(dev);

	spin_unlock_irq(&ep->lock);

	/* Trigger an immediate transmit demand. */
	outl(TxQueued, dev->base_addr + COMMAND);

	dev->trans_start = jiffies;
	if (debug > 4)
		printk(KERN_DEBUG "%s: Queued Tx packet size %d to slot %d, "
			   "flag %2.2x Tx status %8.8x.\n",
			   dev->name, (int)skb->len, entry, ctrl_word,
			   (int)inl(dev->base_addr + TxSTAT));

	return 0;
}

/* The interrupt handler does all of the Rx thread work and cleans up
   after the Tx thread. */
static void epic_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
{
	struct net_device *dev = (struct net_device *)dev_instance;
	struct epic_private *ep = (struct epic_private *)dev->priv;
	long ioaddr = dev->base_addr;
	int status, boguscnt = max_interrupt_work;

	spin_lock(&ep->lock);

	do {
		status = inl(ioaddr + INTSTAT);
		/* Acknowledge all of the current interrupt sources ASAP. */
		outl(status & 0x00007fff, ioaddr + INTSTAT);

		if (debug > 4)
			printk(KERN_DEBUG "%s: Interrupt, status=%#8.8x new "
				   "intstat=%#8.8x.\n",
				   dev->name, status, (int)inl(ioaddr + INTSTAT));

		if ((status & IntrSummary) == 0)
			break;

		if (status & (RxDone | RxStarted | RxEarlyWarn | RxOverflow))
			epic_rx(dev);

		if (status & (TxEmpty | TxDone)) {
			unsigned int dirty_tx, cur_tx;

			/* Note: if this lock becomes a problem we can narrow the locked
			   region at the cost of occasionally grabbing the lock more
			   times. */
			cur_tx = ep->cur_tx;
			dirty_tx = ep->dirty_tx;
			for (; cur_tx - dirty_tx > 0; dirty_tx++) {
				int entry = dirty_tx % TX_RING_SIZE;
				int txstatus = le32_to_cpu(ep->tx_ring[entry].txstatus);

				if (txstatus & DescOwn)
					break;			/* It still hasn't been Txed */

				if ( ! (txstatus & 0x0001)) {
					/* There was an major error, log it. */
#ifndef final_version
					if (debug > 1)
						printk("%s: Transmit error, Tx status %8.8x.\n",
							   dev->name, txstatus);
#endif
					ep->stats.tx_errors++;
					if (txstatus & 0x1050) ep->stats.tx_aborted_errors++;
					if (txstatus & 0x0008) ep->stats.tx_carrier_errors++;
					if (txstatus & 0x0040) ep->stats.tx_window_errors++;
					if (txstatus & 0x0010) ep->stats.tx_fifo_errors++;
#ifdef ETHER_STATS
					if (txstatus & 0x1000) ep->stats.collisions16++;
#endif
				} else {
#ifdef ETHER_STATS
					if ((txstatus & 0x0002) != 0) ep->stats.tx_deferred++;
#endif
					ep->stats.collisions += (txstatus >> 8) & 15;
					ep->stats.tx_packets++;
					ep->stats.tx_bytes += ep->tx_skbuff[entry]->len;
				}

				/* Free the original skb. */
				dev_kfree_skb_irq(ep->tx_skbuff[entry]);
				ep->tx_skbuff[entry] = 0;
			}

#ifndef final_version
			if (cur_tx - dirty_tx > TX_RING_SIZE) {
				printk("%s: Out-of-sync dirty pointer, %d vs. %d, full=%d.\n",
					   dev->name, dirty_tx, cur_tx, ep->tx_full);
				dirty_tx += TX_RING_SIZE;
			}
#endif
			ep->dirty_tx = dirty_tx;
			if (ep->tx_full
				&& cur_tx - dirty_tx < TX_QUEUE_LEN - 4) {
				/* The ring is no longer full, clear tbusy. */
				ep->tx_full = 0;
				netif_wake_queue(dev);
			}
		}

		/* Check uncommon events all at once. */
		if (status & (CntFull | TxUnderrun | RxOverflow | RxFull |
					  PCIBusErr170 | PCIBusErr175)) {
			if (status == 0xffffffff) /* Chip failed or removed (CardBus). */
				break;
			/* Always update the error counts to avoid overhead later. */
			ep->stats.rx_missed_errors += inb(ioaddr + MPCNT);
			ep->stats.rx_frame_errors += inb(ioaddr + ALICNT);
			ep->stats.rx_crc_errors += inb(ioaddr + CRCCNT);

			if (status & TxUnderrun) { /* Tx FIFO underflow. */
				ep->stats.tx_fifo_errors++;
				outl(ep->tx_threshold += 128, ioaddr + TxThresh);
				/* Restart the transmit process. */
				outl(RestartTx, ioaddr + COMMAND);
			}
			if (status & RxOverflow) {		/* Missed a Rx frame. */
				ep->stats.rx_errors++;
			}
			if (status & (RxOverflow | RxFull))
				outw(RxQueued, ioaddr + COMMAND);
			if (status & PCIBusErr170) {
				printk(KERN_ERR "%s: PCI Bus Error!  EPIC status %4.4x.\n",
					   dev->name, status);
				epic_pause(dev);
				epic_restart(dev);
			}
			/* Clear all error sources. */
			outl(status & 0x7f18, ioaddr + INTSTAT);
		}
		if (--boguscnt < 0) {
			printk(KERN_ERR "%s: Too much work at interrupt, "
				   "IntrStatus=0x%8.8x.\n",
				   dev->name, status);
			/* Clear all interrupt sources. */
			outl(0x0001ffff, ioaddr + INTSTAT);
			break;
		}
	} while (1);

	if (debug > 3)
		printk(KERN_DEBUG "%s: exiting interrupt, intr_status=%#4.4x.\n",
			   dev->name, status);

	spin_unlock(&ep->lock);
}

static int epic_rx(struct net_device *dev)
{
	struct epic_private *ep = (struct epic_private *)dev->priv;
	int entry = ep->cur_rx % RX_RING_SIZE;
	int rx_work_limit = ep->dirty_rx + RX_RING_SIZE - ep->cur_rx;
	int work_done = 0;

	if (debug > 4)
		printk(KERN_DEBUG " In epic_rx(), entry %d %8.8x.\n", entry,
			   ep->rx_ring[entry].rxstatus);
	/* If we own the next entry, it's a new packet. Send it up. */
	while (!(le32_to_cpu(ep->rx_ring[entry].rxstatus) & DescOwn)) { 
		int status = le32_to_cpu(ep->rx_ring[entry].rxstatus);

		if (debug > 4)
			printk(KERN_DEBUG "  epic_rx() status was %8.8x.\n", status);
		if (--rx_work_limit < 0)
			break;
		if (status & 0x2006) {
			if (debug > 2)
				printk(KERN_DEBUG "%s: epic_rx() error status was %8.8x.\n",
					   dev->name, status);
			if (status & 0x2000) {
				printk(KERN_WARNING "%s: Oversized Ethernet frame spanned "
					   "multiple buffers, status %4.4x!\n", dev->name, status);
				ep->stats.rx_length_errors++;
			} else if (status & 0x0006)
				/* Rx Frame errors are counted in hardware. */
				ep->stats.rx_errors++;
		} else {
			/* Malloc up new buffer, compatible with net-2e. */
			/* Omit the four octet CRC from the length. */
			short pkt_len = (status >> 16) - 4;
			struct sk_buff *skb;

			if (pkt_len > PKT_BUF_SZ - 4) {
				printk(KERN_ERR "%s: Oversized Ethernet frame, status %x "
					   "%d bytes.\n",
					   dev->name, pkt_len, status);
				pkt_len = 1514;
			}
			/* Check if the packet is long enough to accept without copying
			   to a minimally-sized skbuff. */
			if (pkt_len < rx_copybreak
				&& (skb = dev_alloc_skb(pkt_len + 2)) != NULL) {
				skb->dev = dev;
				skb_reserve(skb, 2);	/* 16 byte align the IP header */
#if 1 /* HAS_IP_COPYSUM */
				eth_copy_and_sum(skb, ep->rx_skbuff[entry]->tail, pkt_len, 0);
				skb_put(skb, pkt_len);
#else
				memcpy(skb_put(skb, pkt_len), ep->rx_skbuff[entry]->tail,
					   pkt_len);
#endif
			} else {
				skb_put(skb = ep->rx_skbuff[entry], pkt_len);
				ep->rx_skbuff[entry] = NULL;
			}
			skb->protocol = eth_type_trans(skb, dev);
			netif_rx(skb);
			ep->stats.rx_packets++;
			ep->stats.rx_bytes += pkt_len;
		}
		work_done++;
		entry = (++ep->cur_rx) % RX_RING_SIZE;
	}

	/* Refill the Rx ring buffers. */
	for (; ep->cur_rx - ep->dirty_rx > 0; ep->dirty_rx++) {
		entry = ep->dirty_rx % RX_RING_SIZE;
		if (ep->rx_skbuff[entry] == NULL) {
			struct sk_buff *skb;
			skb = ep->rx_skbuff[entry] = dev_alloc_skb(ep->rx_buf_sz);
			if (skb == NULL)
				break;
			skb->dev = dev;			/* Mark as being used by this device. */
			skb_reserve(skb, 2);	/* Align IP on 16 byte boundaries */
			ep->rx_ring[entry].bufaddr = virt_to_le32desc(skb->tail);
			work_done++;
		}
		ep->rx_ring[entry].rxstatus = cpu_to_le32(DescOwn);
	}
	return work_done;
}

static int epic_close(struct net_device *dev)
{
	long ioaddr = dev->base_addr;
	struct epic_private *ep = (struct epic_private *)dev->priv;
	int i;

	netif_stop_queue(dev);

	if (debug > 1)
		printk(KERN_DEBUG "%s: Shutting down ethercard, status was %2.2x.\n",
			   dev->name, (int)inl(ioaddr + INTSTAT));

	del_timer_sync(&ep->timer);
	epic_pause(dev);
	free_irq(dev->irq, dev);

	/* Free all the skbuffs in the Rx queue. */
	for (i = 0; i < RX_RING_SIZE; i++) {
		struct sk_buff *skb = ep->rx_skbuff[i];
		ep->rx_skbuff[i] = 0;
		ep->rx_ring[i].rxstatus = 0;		/* Not owned by Epic chip. */
		ep->rx_ring[i].buflength = 0;
		ep->rx_ring[i].bufaddr = 0xBADF00D0; /* An invalid address. */
		if (skb) {
			dev_kfree_skb(skb);
		}
	}
	for (i = 0; i < TX_RING_SIZE; i++) {
		if (ep->tx_skbuff[i])
			dev_kfree_skb(ep->tx_skbuff[i]);
		ep->tx_skbuff[i] = 0;
	}

	/* Green! Leave the chip in low-power mode. */
	outl(0x0008, ioaddr + GENCTL);

	MOD_DEC_USE_COUNT;
	return 0;
}

static struct net_device_stats *epic_get_stats(struct net_device *dev)
{
	struct epic_private *ep = (struct epic_private *)dev->priv;
	long ioaddr = dev->base_addr;

	if (netif_running(dev)) {
		/* Update the error counts. */
		ep->stats.rx_missed_errors += inb(ioaddr + MPCNT);
		ep->stats.rx_frame_errors += inb(ioaddr + ALICNT);
		ep->stats.rx_crc_errors += inb(ioaddr + CRCCNT);
	}

	return &ep->stats;
}

/* Set or clear the multicast filter for this adaptor.
   Note that we only use exclusion around actually queueing the
   new frame, not around filling ep->setup_frame.  This is non-deterministic
   when re-entered but still correct. */

/* The little-endian AUTODIN II ethernet CRC calculation.
   N.B. Do not use for bulk data, use a table-based routine instead.
   This is common code and should be moved to net/core/crc.c */
static unsigned const ethernet_polynomial_le = 0xedb88320U;
static inline unsigned ether_crc_le(int length, unsigned char *data)
{
	unsigned int crc = 0xffffffff;	/* Initial value. */
	while(--length >= 0) {
		unsigned char current_octet = *data++;
		int bit;
		for (bit = 8; --bit >= 0; current_octet >>= 1) {
			if ((crc ^ current_octet) & 1) {
				crc >>= 1;
				crc ^= ethernet_polynomial_le;
			} else
				crc >>= 1;
		}
	}
	return crc;
}

static void set_rx_mode(struct net_device *dev)
{
	long ioaddr = dev->base_addr;
	struct epic_private *ep = (struct epic_private *)dev->priv;
	unsigned char mc_filter[8];		 /* Multicast hash filter */
	int i;

	if (dev->flags & IFF_PROMISC) {			/* Set promiscuous. */
		outl(0x002C, ioaddr + RxCtrl);
		/* Unconditionally log net taps. */
		printk(KERN_INFO "%s: Promiscuous mode enabled.\n", dev->name);
		memset(mc_filter, 0xff, sizeof(mc_filter));
	} else if ((dev->mc_count > 0)  ||  (dev->flags & IFF_ALLMULTI)) {
		/* There is apparently a chip bug, so the multicast filter
		   is never enabled. */
		/* Too many to filter perfectly -- accept all multicasts. */
		memset(mc_filter, 0xff, sizeof(mc_filter));
		outl(0x000C, ioaddr + RxCtrl);
	} else if (dev->mc_count == 0) {
		outl(0x0004, ioaddr + RxCtrl);
		return;
	} else {					/* Never executed, for now. */
		struct dev_mc_list *mclist;

		memset(mc_filter, 0, sizeof(mc_filter));
		for (i = 0, mclist = dev->mc_list; mclist && i < dev->mc_count;
			 i++, mclist = mclist->next)
			set_bit(ether_crc_le(ETH_ALEN, mclist->dmi_addr) & 0x3f,
					mc_filter);
	}
	/* ToDo: perhaps we need to stop the Tx and Rx process here? */
	if (memcmp(mc_filter, ep->mc_filter, sizeof(mc_filter))) {
		for (i = 0; i < 4; i++)
			outw(((u16 *)mc_filter)[i], ioaddr + MC0 + i*4);
		memcpy(ep->mc_filter, mc_filter, sizeof(mc_filter));
	}
	return;
}

static int mii_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
	long ioaddr = dev->base_addr;
	u16 *data = (u16 *)&rq->ifr_data;

	switch(cmd) {
	case SIOCDEVPRIVATE:		/* Get the address of the PHY in use. */
		data[0] = ((struct epic_private *)dev->priv)->phys[0] & 0x1f;
		/* Fall Through */
	case SIOCDEVPRIVATE+1:		/* Read the specified MII register. */
		if (! netif_running(dev)) {
			outl(0x0200, ioaddr + GENCTL);
			outl((inl(ioaddr + NVCTL) & ~0x003C) | 0x4800, ioaddr + NVCTL);
		}
		data[3] = mdio_read(ioaddr, data[0] & 0x1f, data[1] & 0x1f);
		if (! netif_running(dev)) {
#ifdef notdef					/* Leave on if the ioctl() is used. */
			outl(0x0008, ioaddr + GENCTL);
			outl((inl(ioaddr + NVCTL) & ~0x483C) | 0x0000, ioaddr + NVCTL);
#endif
		}
		return 0;
	case SIOCDEVPRIVATE+2:		/* Write the specified MII register */
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		if (! netif_running(dev)) {
			outl(0x0200, ioaddr + GENCTL);
			outl((inl(ioaddr + NVCTL) & ~0x003C) | 0x4800, ioaddr + NVCTL);
		}
		mdio_write(ioaddr, data[0] & 0x1f, data[1] & 0x1f, data[2]);
		if (! netif_running(dev)) {
#ifdef notdef					/* Leave on if the ioctl() is used. */
			outl(0x0008, ioaddr + GENCTL);
			outl((inl(ioaddr + NVCTL) & ~0x483C) | 0x0000, ioaddr + NVCTL);
#endif
		}
		return 0;
	default:
		return -EOPNOTSUPP;
	}
}


static void __devexit epic_remove_one (struct pci_dev *pdev)
{
	struct net_device *dev = pdev->driver_data;
	
	unregister_netdev(dev);
#ifndef USE_IO_OPS
	iounmap ((void*) dev->base_addr);
#endif
	release_mem_region (pci_resource_start (pdev, 1),
			    pci_resource_len (pdev, 1));
	release_region (pci_resource_start (pdev, 0),
			pci_resource_len (pdev, 0));
	kfree(dev);
}


static void epic_suspend (struct pci_dev *pdev)
{
	struct net_device *dev = pdev->driver_data;
	long ioaddr = dev->base_addr;

	epic_pause(dev);
	/* Put the chip into low-power mode. */
	outl(0x0008, ioaddr + GENCTL);
}


static void epic_resume (struct pci_dev *pdev)
{
	struct net_device *dev = pdev->driver_data;

	epic_restart (dev);
}


static struct pci_driver epic_driver = {
	name:		"epic100",
	id_table:	epic_pci_tbl,
	probe:		epic_init_one,
	remove:		epic_remove_one,
	suspend:	epic_suspend,
	resume:		epic_resume,
};


static int __init epic_init (void)
{
	return pci_module_init (&epic_driver);
}


static void __exit epic_cleanup (void)
{
	pci_unregister_driver (&epic_driver);
}


module_init(epic_init);
module_exit(epic_cleanup);