NetBSD/sys/dev/isa/if_ed.c

/*	$NetBSD: if_ed.c,v 1.79 1995/07/23 20:36:51 mycroft Exp $	*/

/*
 * Device driver for National Semiconductor DS8390/WD83C690 based ethernet
 * adapters.
 *
 * Copyright (c) 1994, 1995 Charles M. Hannum.  All rights reserved.
 *
 * Copyright (C) 1993, David Greenman.  This software may be used, modified,
 * copied, distributed, and sold, in both source and binary form provided that
 * the above copyright and these terms are retained.  Under no circumstances is
 * the author responsible for the proper functioning of this software, nor does
 * the author assume any responsibility for damages incurred with its use.
 *
 * Currently supports the Western Digital/SMC 8003 and 8013 series, the SMC
 * Elite Ultra (8216), the 3Com 3c503, the NE1000 and NE2000, and a variety of
 * similar clones.
 */

#include "bpfilter.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/device.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/netisr.h>

#ifdef INET
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#endif

#ifdef NS
#include <netns/ns.h>
#include <netns/ns_if.h>
#endif

#if NBPFILTER > 0
#include <net/bpf.h>
#include <net/bpfdesc.h>
#endif

#include <machine/cpu.h>
#include <machine/pio.h>

#include <dev/isa/isareg.h>
#include <dev/isa/isavar.h>
#include <i386/isa/isa_machdep.h>	/* XXX USES ISA HOLE DIRECTLY */
#include <dev/ic/dp8390reg.h>
#include <dev/isa/if_edreg.h>

/*
 * ed_softc: per line info and status
 */
struct ed_softc {
	struct	device sc_dev;
	void *sc_ih;

	struct	arpcom sc_arpcom;	/* ethernet common */

	char	*type_str;	/* pointer to type string */
	u_char	vendor;		/* interface vendor */
	u_char	type;		/* interface type code */

	int	asic_addr;	/* ASIC I/O bus address */
	int	nic_addr;	/* NIC (DS8390) I/O bus address */

/*
 * The following 'proto' variable is part of a work-around for 8013EBT asics
 * being write-only.  It's sort of a prototype/shadow of the real thing.
 */
	u_char	wd_laar_proto;
/*
 * This `proto' variable is so we can turn MENB on and off without reading
 * the value back from the card all the time.
 */
	u_char	wd_msr_proto;
	u_char	cr_proto;	/* values always set in CR */
	u_char	isa16bit;	/* width of access to card 0=8 or 1=16 */
	u_char	is790;		/* set by probe if NIC is a 790 */

	caddr_t	mem_start;	/* NIC memory start address */
	caddr_t	mem_end;	/* NIC memory end address */
	u_long	mem_size;	/* total NIC memory size */
	caddr_t	mem_ring;	/* start of RX ring-buffer (in NIC mem) */

	u_char	mem_shared;	/* NIC memory is shared with host */
	u_char	xmit_busy;	/* transmitter is busy */
	u_char	txb_cnt;	/* number of transmit buffers */
	u_char	txb_inuse;	/* number of TX buffers currently in-use*/

	u_char 	txb_new;	/* pointer to where new buffer will be added */
	u_char	txb_next_tx;	/* pointer to next buffer ready to xmit */
	u_short	txb_len[8];	/* buffered xmit buffer lengths */
	u_char	tx_page_start;	/* first page of TX buffer area */
	u_char	rec_page_start;	/* first page of RX ring-buffer */
	u_char	rec_page_stop;	/* last page of RX ring-buffer */
	u_char	next_packet;	/* pointer to next unread RX packet */
};

int edprobe __P((struct device *, void *, void *));
void edattach __P((struct device *, struct device *, void *));
int edintr __P((void *));
int ed_ioctl __P((struct ifnet *, u_long, caddr_t));
void ed_start __P((struct ifnet *));
void ed_watchdog __P((int));
void ed_reset __P((struct ed_softc *));
void ed_init __P((struct ed_softc *));
void ed_stop __P((struct ed_softc *));
void ed_getmcaf __P((struct arpcom *, u_long *));

#define inline	/* XXX for debugging porpoises */

void ed_get_packet __P((struct ed_softc *, caddr_t, u_short));
static inline void ed_rint __P((struct ed_softc *));
static inline void ed_xmit __P((struct ed_softc *));
static inline caddr_t ed_ring_copy __P((struct ed_softc *, caddr_t, caddr_t,
					u_short));

void ed_pio_readmem __P((struct ed_softc *, u_short, caddr_t, u_short));
void ed_pio_writemem __P((struct ed_softc *, caddr_t, u_short, u_short));
u_short ed_pio_write_mbufs __P((struct ed_softc *, struct mbuf *, u_short));

struct cfdriver edcd = {
	NULL, "ed", edprobe, edattach, DV_IFNET, sizeof(struct ed_softc)
};

#define	ETHER_MIN_LEN	64
#define ETHER_MAX_LEN	1518
#define	ETHER_ADDR_LEN	6

#define	NIC_PUT(sc, off, val)	outb(sc->nic_addr + off, val)
#define	NIC_GET(sc, off)	inb(sc->nic_addr + off)

/*
 * Determine if the device is present.
 */
int
edprobe(parent, match, aux)
	struct device *parent;
	void *match, *aux;
{
	struct ed_softc *sc = match;
	struct cfdata *cf = sc->sc_dev.dv_cfdata;
	struct isa_attach_args *ia = aux;

	if (ed_probe_WD80x3(sc, cf, ia))
		return (1);
	if (ed_probe_3Com(sc, cf, ia))
		return (1);
	if (ed_probe_Novell(sc, cf, ia))
		return (1);
	return (0);
}

/*
 * Generic probe routine for testing for the existance of a DS8390.  Must be
 * called after the NIC has just been reset.  This routine works by looking at
 * certain register values that are guaranteed to be initialized a certain way
 * after power-up or reset.  Seems not to currently work on the 83C690.
 *
 * Specifically:
 *
 *	Register			reset bits	set bits
 *	Command Register (CR)		TXP, STA	RD2, STP
 *	Interrupt Status (ISR)				RST
 *	Interrupt Mask (IMR)		All bits
 *	Data Control (DCR)				LAS
 *	Transmit Config. (TCR)		LB1, LB0
 *
 * We only look at the CR and ISR registers, however, because looking at the
 * others would require changing register pages (which would be intrusive if
 * this isn't an 8390).
 *
 * Return 1 if 8390 was found, 0 if not.
 */
int
ed_probe_generic8390(sc)
	struct ed_softc *sc;
{

	if ((NIC_GET(sc, ED_P0_CR) &
	     (ED_CR_RD2 | ED_CR_TXP | ED_CR_STA | ED_CR_STP)) !=
	    (ED_CR_RD2 | ED_CR_STP))
		return (0);
	if ((NIC_GET(sc, ED_P0_ISR) & ED_ISR_RST) != ED_ISR_RST)
		return (0);

	return (1);
}

int ed_wd584_irq[] = { 9, 3, 5, 7, 10, 11, 15, 4 };
int ed_wd790_irq[] = { IRQUNK, 9, 3, 5, 7, 10, 11, 15 };

/*
 * Probe and vendor-specific initialization routine for SMC/WD80x3 boards.
 */
int
ed_probe_WD80x3(sc, cf, ia)
	struct ed_softc *sc;
	struct cfdata *cf;
	struct isa_attach_args *ia;
{
	int i;
	u_int memsize;
	u_char iptr, isa16bit, sum;

	sc->asic_addr = ia->ia_iobase;
	sc->nic_addr = sc->asic_addr + ED_WD_NIC_OFFSET;
	sc->is790 = 0;

#ifdef TOSH_ETHER
	outb(sc->asic_addr + ED_WD_MSR, ED_WD_MSR_POW);
	delay(10000);
#endif

	/*
	 * Attempt to do a checksum over the station address PROM.  If it
	 * fails, it's probably not a SMC/WD board.  There is a problem with
	 * this, though: some clone WD boards don't pass the checksum test.
	 * Danpex boards for one.
	 */
	for (sum = 0, i = 0; i < 8; ++i)
		sum += inb(sc->asic_addr + ED_WD_PROM + i);

	if (sum != ED_WD_ROM_CHECKSUM_TOTAL) {
		/*
		 * Checksum is invalid.  This often happens with cheap WD8003E
		 * clones.  In this case, the checksum byte (the eighth byte)
		 * seems to always be zero.
		 */
		if (inb(sc->asic_addr + ED_WD_CARD_ID) != ED_TYPE_WD8003E ||
		    inb(sc->asic_addr + ED_WD_PROM + 7) != 0)
			return (0);
	}

	/* Reset card to force it into a known state. */
#ifdef TOSH_ETHER
	outb(sc->asic_addr + ED_WD_MSR, ED_WD_MSR_RST | ED_WD_MSR_POW);
#else
	outb(sc->asic_addr + ED_WD_MSR, ED_WD_MSR_RST);
#endif
	delay(100);
	outb(sc->asic_addr + ED_WD_MSR,
	    inb(sc->asic_addr + ED_WD_MSR) & ~ED_WD_MSR_RST);
	/* Wait in the case this card is reading it's EEROM. */
	delay(5000);

	sc->vendor = ED_VENDOR_WD_SMC;
	sc->type = inb(sc->asic_addr + ED_WD_CARD_ID);

	/* Set initial values for width/size. */
	memsize = 8192;
	isa16bit = 0;
	switch (sc->type) {
	case ED_TYPE_WD8003S:
		sc->type_str = "WD8003S";
		break;
	case ED_TYPE_WD8003E:
		sc->type_str = "WD8003E";
		break;
	case ED_TYPE_WD8003EB:
		sc->type_str = "WD8003EB";
		break;
	case ED_TYPE_WD8003W:
		sc->type_str = "WD8003W";
		break;
	case ED_TYPE_WD8013EBT:
		sc->type_str = "WD8013EBT";
		memsize = 16384;
		isa16bit = 1;
		break;
	case ED_TYPE_WD8013W:
		sc->type_str = "WD8013W";
		memsize = 16384;
		isa16bit = 1;
		break;
	case ED_TYPE_WD8013EP:		/* also WD8003EP */
		if (inb(sc->asic_addr + ED_WD_ICR) & ED_WD_ICR_16BIT) {
			isa16bit = 1;
			memsize = 16384;
			sc->type_str = "WD8013EP";
		} else
			sc->type_str = "WD8003EP";
		break;
	case ED_TYPE_WD8013WC:
		sc->type_str = "WD8013WC";
		memsize = 16384;
		isa16bit = 1;
		break;
	case ED_TYPE_WD8013EBP:
		sc->type_str = "WD8013EBP";
		memsize = 16384;
		isa16bit = 1;
		break;
	case ED_TYPE_WD8013EPC:
		sc->type_str = "WD8013EPC";
		memsize = 16384;
		isa16bit = 1;
		break;
	case ED_TYPE_SMC8216C:
		sc->type_str = "SMC8216/SMC8216C";
		memsize = 16384;
		isa16bit = 1;
		sc->is790 = 1;
		break;
	case ED_TYPE_SMC8216T:
		sc->type_str = "SMC8216T";
		memsize = 16384;
		isa16bit = 1;
		sc->is790 = 1;
		break;
#ifdef TOSH_ETHER
	case ED_TYPE_TOSHIBA1:
		sc->type_str = "Toshiba1";
		memsize = 32768;
		isa16bit = 1;
		break;
	case ED_TYPE_TOSHIBA4:
		sc->type_str = "Toshiba4";
		memsize = 32768;
		isa16bit = 1;
		break;
#endif
	default:
		sc->type_str = NULL;
		break;
	}
	/*
	 * Make some adjustments to initial values depending on what is found
	 * in the ICR.
	 */
	if (isa16bit && (sc->type != ED_TYPE_WD8013EBT) &&
#ifdef TOSH_ETHER
	    (sc->type != ED_TYPE_TOSHIBA1) && (sc->type != ED_TYPE_TOSHIBA4) &&
#endif
	    ((inb(sc->asic_addr + ED_WD_ICR) & ED_WD_ICR_16BIT) == 0)) {
		isa16bit = 0;
		memsize = 8192;
	}

#ifdef ED_DEBUG
	printf("type=%x type_str=%s isa16bit=%d memsize=%d id_msize=%d\n",
	    sc->type, sc->type_str ?: "unknown", isa16bit, memsize,
	    ia->ia_msize);
	for (i = 0; i < 8; i++)
		printf("%x -> %x\n", i, inb(sc->asic_addr + i));
#endif
	/* Allow the user to override the autoconfiguration. */
	if (ia->ia_msize)
		memsize = ia->ia_msize;
	/*
	 * (Note that if the user specifies both of the following flags that
	 * '8-bit' mode intentionally has precedence.)
	 */
	if (cf->cf_flags & ED_FLAGS_FORCE_16BIT_MODE)
		isa16bit = 1;
	if (cf->cf_flags & ED_FLAGS_FORCE_8BIT_MODE)
		isa16bit = 0;

	/*
	 * If possible, get the assigned interrupt number from the card and
	 * use it.
	 */
	if (sc->is790) {
		u_char x;
		/* Assemble together the encoded interrupt number. */
		outb(ia->ia_iobase + ED_WD790_HWR,
		    inb(ia->ia_iobase + ED_WD790_HWR) | ED_WD790_HWR_SWH);
		x = inb(ia->ia_iobase + ED_WD790_GCR);
		iptr = ((x & ED_WD790_GCR_IR2) >> 4) |
		    ((x & (ED_WD790_GCR_IR1|ED_WD790_GCR_IR0)) >> 2);
		outb(ia->ia_iobase + ED_WD790_HWR,
		    inb(ia->ia_iobase + ED_WD790_HWR) & ~ED_WD790_HWR_SWH);
		/*
		 * Translate it using translation table, and check for
		 * correctness.
		 */
		if (ia->ia_irq != IRQUNK) {
			if (ia->ia_irq != ed_wd790_irq[iptr]) {
				printf("%s: irq mismatch; kernel configured %d != board configured %d\n",
				    sc->sc_dev.dv_xname, ia->ia_irq,
				    ed_wd790_irq[iptr]);
				return (0);
			}
		} else
			ia->ia_irq = ed_wd790_irq[iptr];
		/* Enable the interrupt. */
		outb(ia->ia_iobase + ED_WD790_ICR,
		    inb(ia->ia_iobase + ED_WD790_ICR) | ED_WD790_ICR_EIL);
	} else if (sc->type & ED_WD_SOFTCONFIG) {
		/* Assemble together the encoded interrupt number. */
		iptr = (inb(ia->ia_iobase + ED_WD_ICR) & ED_WD_ICR_IR2) |
		    ((inb(ia->ia_iobase + ED_WD_IRR) &
		      (ED_WD_IRR_IR0 | ED_WD_IRR_IR1)) >> 5);
		/*
		 * Translate it using translation table, and check for
		 * correctness.
		 */
		if (ia->ia_irq != IRQUNK) {
			if (ia->ia_irq != ed_wd584_irq[iptr]) {
				printf("%s: irq mismatch; kernel configured %d != board configured %d\n",
				    sc->sc_dev.dv_xname, ia->ia_irq,
				    ed_wd584_irq[iptr]);
				return (0);
			}
		} else
			ia->ia_irq = ed_wd584_irq[iptr];
		/* Enable the interrupt. */
		outb(ia->ia_iobase + ED_WD_IRR,
		    inb(ia->ia_iobase + ED_WD_IRR) | ED_WD_IRR_IEN);
	} else {
		if (ia->ia_irq == IRQUNK) {
			printf("%s: %s does not have soft configuration\n",
			    sc->sc_dev.dv_xname, sc->type_str);
			return (0);
		}
	}

	/* XXX Figure out the shared memory address. */

	sc->isa16bit = isa16bit;
	sc->mem_shared = 1;
	ia->ia_msize = memsize;
	sc->mem_start = ISA_HOLE_VADDR(ia->ia_maddr);

	/* Allocate one xmit buffer if < 16k, two buffers otherwise. */
	if ((memsize < 16384) || (cf->cf_flags & ED_FLAGS_NO_MULTI_BUFFERING))
		sc->txb_cnt = 1;
	else
		sc->txb_cnt = 2;

	sc->tx_page_start = ED_WD_PAGE_OFFSET;
	sc->rec_page_start = sc->tx_page_start + sc->txb_cnt * ED_TXBUF_SIZE;
	sc->rec_page_stop = sc->tx_page_start + (memsize >> ED_PAGE_SHIFT);
	sc->mem_ring = sc->mem_start + (sc->rec_page_start << ED_PAGE_SHIFT);
	sc->mem_size = memsize;
	sc->mem_end = sc->mem_start + memsize;

	/* Get station address from on-board ROM. */
	for (i = 0; i < ETHER_ADDR_LEN; ++i)
		sc->sc_arpcom.ac_enaddr[i] =
		    inb(sc->asic_addr + ED_WD_PROM + i);

	/*
	 * Set upper address bits and 8/16 bit access to shared memory.
	 */
	if (isa16bit) {
		if (sc->is790) {
			sc->wd_laar_proto =
			    inb(sc->asic_addr + ED_WD_LAAR) &
			    ~ED_WD_LAAR_M16EN;
		} else {
			sc->wd_laar_proto =
			    ED_WD_LAAR_L16EN |
			    ((kvtop(sc->mem_start) >> 19) &
			    ED_WD_LAAR_ADDRHI);
		}
		outb(sc->asic_addr + ED_WD_LAAR,
		    sc->wd_laar_proto | ED_WD_LAAR_M16EN);
	} else  {
		if ((sc->type & ED_WD_SOFTCONFIG) ||
#ifdef TOSH_ETHER
		    (sc->type == ED_TYPE_TOSHIBA1) ||
		    (sc->type == ED_TYPE_TOSHIBA4) ||
#endif
		    (sc->type == ED_TYPE_WD8013EBT) && !sc->is790) {
			sc->wd_laar_proto =
			    ((kvtop(sc->mem_start) >> 19) &
			    ED_WD_LAAR_ADDRHI);
			outb(sc->asic_addr + ED_WD_LAAR,
			    sc->wd_laar_proto);
		}
	}

	/*
	 * Set address and enable interface shared memory.
	 */
	if (!sc->is790) {
#ifdef TOSH_ETHER
		outb(sc->asic_addr + ED_WD_MSR + 1,
		    ((kvtop(sc->mem_start) >> 8) & 0xe0) | 4);
		outb(sc->asic_addr + ED_WD_MSR + 2,
		    ((kvtop(sc->mem_start) >> 16) & 0x0f));
		sc->wd_msr_proto = ED_WD_MSR_POW;
#else
		sc->wd_msr_proto =
		    (kvtop(sc->mem_start) >> 13) & ED_WD_MSR_ADDR;
#endif
		sc->cr_proto = ED_CR_RD2;
	} else {
		outb(sc->asic_addr + 0x04,
		    inb(sc->asic_addr + 0x04) | 0x80);
		outb(sc->asic_addr + 0x0b,
		    ((kvtop(sc->mem_start) >> 13) & 0x0f) |
		    ((kvtop(sc->mem_start) >> 11) & 0x40) |
		    (inb(sc->asic_addr + 0x0b) & 0xb0));
		outb(sc->asic_addr + 0x04,
		    inb(sc->asic_addr + 0x04) & ~0x80);
		sc->wd_msr_proto = 0x00;
		sc->cr_proto = 0;
	}
	outb(sc->asic_addr + ED_WD_MSR,
	    sc->wd_msr_proto | ED_WD_MSR_MENB);

	(void) inb(0x84);
	(void) inb(0x84);

	/* Now zero memory and verify that it is clear. */
	bzero(sc->mem_start, memsize);

	for (i = 0; i < memsize; ++i)
		if (sc->mem_start[i]) {
			printf("%s: failed to clear shared memory at %x - check configuration\n",
			    sc->sc_dev.dv_xname,
			    kvtop(sc->mem_start + i));

			/* Disable 16 bit access to shared memory. */
			outb(sc->asic_addr + ED_WD_MSR,
			    sc->wd_msr_proto);
			if (isa16bit)
				outb(sc->asic_addr + ED_WD_LAAR,
				    sc->wd_laar_proto);
			(void) inb(0x84);
			(void) inb(0x84);
			return (0);
		}

	/*
	 * Disable 16bit access to shared memory - we leave it disabled
	 * so that 1) machines reboot properly when the board is set 16
	 * 16 bit mode and there are conflicting 8bit devices/ROMS in
	 * the same 128k address space as this boards shared memory,
	 * and 2) so that other 8 bit devices with shared memory can be
	 * used in this 128k region, too.
	 */
	outb(sc->asic_addr + ED_WD_MSR, sc->wd_msr_proto);
	if (isa16bit)
		outb(sc->asic_addr + ED_WD_LAAR, sc->wd_laar_proto);
	(void) inb(0x84);
	(void) inb(0x84);

	ia->ia_iosize = ED_WD_IO_PORTS;
	return (1);
}

int ed_3com_iobase[] = {0x2e0, 0x2a0, 0x280, 0x250, 0x350, 0x330, 0x310, 0x300};
int ed_3com_maddr[] = {MADDRUNK, MADDRUNK, MADDRUNK, MADDRUNK, 0xc8000, 0xcc000, 0xd8000, 0xdc000};
#if 0
int ed_3com_irq[] = {IRQUNK, IRQUNK, IRQUNK, IRQUNK, 9, 3, 4, 5};
#endif

/*
 * Probe and vendor-specific initialization routine for 3Com 3c503 boards.
 */
int
ed_probe_3Com(sc, cf, ia)
	struct ed_softc *sc;
	struct cfdata *cf;
	struct isa_attach_args *ia;
{
	int i;
	u_int memsize;
	u_char isa16bit, sum, x;
	int ptr;

	sc->asic_addr = ia->ia_iobase + ED_3COM_ASIC_OFFSET;
	sc->nic_addr = ia->ia_iobase + ED_3COM_NIC_OFFSET;

	/*
	 * Verify that the kernel configured I/O address matches the board
	 * configured address.
	 *
	 * This is really only useful to see if something that looks like the
	 * board is there; after all, we are already talking it at that
	 * address.
	 */
	x = inb(sc->asic_addr + ED_3COM_BCFR);
	if (x == 0 || (x & (x - 1)) != 0)
		return (0);
	ptr = ffs(x) - 1;
	if (ia->ia_iobase != IOBASEUNK) {
		if (ia->ia_iobase != ed_3com_iobase[ptr]) {
			printf("%s: %s mismatch; kernel configured %x != board configured %x\n",
			    "iobase", sc->sc_dev.dv_xname, ia->ia_iobase,
			    ed_3com_iobase[ptr]);
			return (0);
		}
	} else
		ia->ia_iobase = ed_3com_iobase[ptr];

	x = inb(sc->asic_addr + ED_3COM_PCFR);
	if (x == 0 || (x & (x - 1)) != 0)
		return (0);
	ptr = ffs(x) - 1;
	if (ia->ia_maddr != MADDRUNK) {
		if (ia->ia_maddr != ed_3com_maddr[ptr]) {
			printf("%s: %s mismatch; kernel configured %x != board configured %x\n",
			    "maddr", sc->sc_dev.dv_xname, ia->ia_maddr,
			    ed_3com_maddr[ptr]);
			return (0);
		}
	} else
		ia->ia_maddr = ed_3com_maddr[ptr];

#if 0
	x = inb(sc->asic_addr + ED_3COM_IDCFR) & ED_3COM_IDCFR_IRQ;
	if (x == 0 || (x & (x - 1)) != 0)
		return (0);
	ptr = ffs(x) - 1;
	if (ia->ia_irq != IRQUNK) {
		if (ia->ia_irq != ed_3com_irq[ptr]) {
			printf("%s: irq mismatch; kernel configured %d != board configured %d\n",
			    sc->sc_dev.dv_xname, ia->ia_irq,
			    ed_3com_irq[ptr]);
			return (0);
		}
	} else
		ia->ia_irq = ed_3com_irq[ptr];
#endif

	/*
	 * Reset NIC and ASIC.  Enable on-board transceiver throughout reset
	 * sequence because it'll lock up if the cable isn't connected if we
	 * don't.
	 */
	outb(sc->asic_addr + ED_3COM_CR, ED_3COM_CR_RST | ED_3COM_CR_XSEL);

	/* Wait for a while, then un-reset it. */
	delay(50);

	/*
	 * The 3Com ASIC defaults to rather strange settings for the CR after a
	 * reset - it's important to set it again after the following outb
	 * (this is done when we map the PROM below).
	 */
	outb(sc->asic_addr + ED_3COM_CR, ED_3COM_CR_XSEL);

	/* Wait a bit for the NIC to recover from the reset. */
	delay(5000);

	sc->vendor = ED_VENDOR_3COM;
	sc->type_str = "3c503";
	sc->mem_shared = 1;
	sc->cr_proto = ED_CR_RD2;

	/*
	 * Hmmm...a 16bit 3Com board has 16k of memory, but only an 8k window
	 * to it.
	 */
	memsize = 8192;

	/*
	 * Get station address from on-board ROM.
	 *
	 * First, map ethernet address PROM over the top of where the NIC
	 * registers normally appear.
	 */
	outb(sc->asic_addr + ED_3COM_CR, ED_3COM_CR_EALO | ED_3COM_CR_XSEL);

	for (i = 0; i < ETHER_ADDR_LEN; ++i)
		sc->sc_arpcom.ac_enaddr[i] = NIC_GET(sc, i);

	/*
	 * Unmap PROM - select NIC registers.  The proper setting of the
	 * tranceiver is set in ed_init so that the attach code is given a
	 * chance to set the default based on a compile-time config option.
	 */
	outb(sc->asic_addr + ED_3COM_CR, ED_3COM_CR_XSEL);

	/* Determine if this is an 8bit or 16bit board. */

	/* Select page 0 registers. */
	NIC_PUT(sc, ED_P0_CR, ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STP);

	/*
	 * Attempt to clear WTS bit.  If it doesn't clear, then this is a
	 * 16-bit board.
	 */
	NIC_PUT(sc, ED_P0_DCR, 0);

	/* Select page 2 registers. */
	NIC_PUT(sc, ED_P0_CR, ED_CR_RD2 | ED_CR_PAGE_2 | ED_CR_STP);

	/* The 3c503 forces the WTS bit to a one if this is a 16bit board. */
	if (NIC_GET(sc, ED_P2_DCR) & ED_DCR_WTS)
		isa16bit = 1;
	else
		isa16bit = 0;

	/* Select page 0 registers. */
	NIC_PUT(sc, ED_P2_CR, ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STP);

	sc->mem_start = ISA_HOLE_VADDR(ia->ia_maddr);
	sc->mem_size = memsize;
	sc->mem_end = sc->mem_start + memsize;

	/*
	 * We have an entire 8k window to put the transmit buffers on the
	 * 16-bit boards.  But since the 16bit 3c503's shared memory is only
	 * fast enough to overlap the loading of one full-size packet, trying
	 * to load more than 2 buffers can actually leave the transmitter idle
	 * during the load.  So 2 seems the best value.  (Although a mix of
	 * variable-sized packets might change this assumption.  Nonetheless,
	 * we optimize for linear transfers of same-size packets.)
	 */
	if (isa16bit) {
 		if (cf->cf_flags & ED_FLAGS_NO_MULTI_BUFFERING)
			sc->txb_cnt = 1;
		else
			sc->txb_cnt = 2;

		sc->tx_page_start = ED_3COM_TX_PAGE_OFFSET_16BIT;
		sc->rec_page_start = ED_3COM_RX_PAGE_OFFSET_16BIT;
		sc->rec_page_stop =
		    (memsize >> ED_PAGE_SHIFT) + ED_3COM_RX_PAGE_OFFSET_16BIT;
		sc->mem_ring = sc->mem_start;
	} else {
		sc->txb_cnt = 1;
		sc->tx_page_start = ED_3COM_TX_PAGE_OFFSET_8BIT;
		sc->rec_page_start =
		    ED_TXBUF_SIZE + ED_3COM_TX_PAGE_OFFSET_8BIT;
		sc->rec_page_stop =
		    (memsize >> ED_PAGE_SHIFT) + ED_3COM_TX_PAGE_OFFSET_8BIT;
		sc->mem_ring =
		    sc->mem_start + (ED_TXBUF_SIZE << ED_PAGE_SHIFT);
	}

	sc->isa16bit = isa16bit;

	/*
	 * Initialize GA page start/stop registers.  Probably only needed if
	 * doing DMA, but what the Hell.
	 */
	outb(sc->asic_addr + ED_3COM_PSTR, sc->rec_page_start);
	outb(sc->asic_addr + ED_3COM_PSPR, sc->rec_page_stop);

	/* Set IRQ.  3c503 only allows a choice of irq 3-5 or 9. */
	switch (ia->ia_irq) {
	case 9:
		outb(sc->asic_addr + ED_3COM_IDCFR, ED_3COM_IDCFR_IRQ2);
		break;
	case 3:
		outb(sc->asic_addr + ED_3COM_IDCFR, ED_3COM_IDCFR_IRQ3);
		break;
	case 4:
		outb(sc->asic_addr + ED_3COM_IDCFR, ED_3COM_IDCFR_IRQ4);
		break;
	case 5:
		outb(sc->asic_addr + ED_3COM_IDCFR, ED_3COM_IDCFR_IRQ5);
		break;
	default:
		printf("%s: invalid irq configuration (%d) must be 3-5 or 9 for 3c503\n",
		    sc->sc_dev.dv_xname, ia->ia_irq);
		return (0);
	}

	/*
	 * Initialize GA configuration register.  Set bank and enable shared
	 * mem.
	 */
	outb(sc->asic_addr + ED_3COM_GACFR,
	    ED_3COM_GACFR_RSEL | ED_3COM_GACFR_MBS0);

	/*
	 * Initialize "Vector Pointer" registers. These gawd-awful things are
	 * compared to 20 bits of the address on ISA, and if they match, the
	 * shared memory is disabled. We set them to 0xffff0...allegedly the
	 * reset vector.
	 */
	outb(sc->asic_addr + ED_3COM_VPTR2, 0xff);
	outb(sc->asic_addr + ED_3COM_VPTR1, 0xff);
	outb(sc->asic_addr + ED_3COM_VPTR0, 0x00);

	/* Zero memory and verify that it is clear. */
	bzero(sc->mem_start, memsize);

	for (i = 0; i < memsize; ++i)
		if (sc->mem_start[i]) {
			printf("%s: failed to clear shared memory at %x - check configuration\n",
			    sc->sc_dev.dv_xname, kvtop(sc->mem_start + i));
			return (0);
		}

	ia->ia_msize = memsize;
	ia->ia_iosize = ED_3COM_IO_PORTS;
	return (1);
}

/*
 * Probe and vendor-specific initialization routine for NE1000/2000 boards.
 */
int
ed_probe_Novell(sc, cf, ia)
	struct ed_softc *sc;
	struct cfdata *cf;
	struct isa_attach_args *ia;
{
	u_int memsize, n;
	u_char romdata[16], isa16bit = 0, tmp;
	static u_char test_pattern[32] = "THIS is A memory TEST pattern";
	u_char test_buffer[32];

	sc->asic_addr = ia->ia_iobase + ED_NOVELL_ASIC_OFFSET;
	sc->nic_addr = ia->ia_iobase + ED_NOVELL_NIC_OFFSET;

	/* XXX - do Novell-specific probe here */

	/* Reset the board. */
#ifdef GWETHER
	outb(sc->asic_addr + ED_NOVELL_RESET, 0);
	delay(200);
#endif /* GWETHER */
	tmp = inb(sc->asic_addr + ED_NOVELL_RESET);

	/*
	 * I don't know if this is necessary; probably cruft leftover from
	 * Clarkson packet driver code. Doesn't do a thing on the boards I've
	 * tested. -DG [note that a outb(0x84, 0) seems to work here, and is
	 * non-invasive...but some boards don't seem to reset and I don't have
	 * complete documentation on what the 'right' thing to do is...so we do
	 * the invasive thing for now.  Yuck.]
	 */
	outb(sc->asic_addr + ED_NOVELL_RESET, tmp);
	delay(5000);

	/*
	 * This is needed because some NE clones apparently don't reset the NIC
	 * properly (or the NIC chip doesn't reset fully on power-up)
	 * XXX - this makes the probe invasive! ...Done against my better
	 * judgement.  -DLG
	 */
	NIC_PUT(sc, ED_P0_CR, ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STP);

	delay(5000);

	/* Make sure that we really have an 8390 based board. */
	if (!ed_probe_generic8390(sc))
		return (0);

	sc->vendor = ED_VENDOR_NOVELL;
	sc->mem_shared = 0;
	sc->cr_proto = ED_CR_RD2;
	ia->ia_msize = 0;

	/*
	 * Test the ability to read and write to the NIC memory.  This has the
	 * side affect of determining if this is an NE1000 or an NE2000.
	 */

	/*
	 * This prevents packets from being stored in the NIC memory when the
	 * readmem routine turns on the start bit in the CR.
	 */
	NIC_PUT(sc, ED_P0_RCR, ED_RCR_MON);

	/* Temporarily initialize DCR for byte operations. */
	NIC_PUT(sc, ED_P0_DCR, ED_DCR_FT1 | ED_DCR_LS);

	NIC_PUT(sc, ED_P0_PSTART, 8192 >> ED_PAGE_SHIFT);
	NIC_PUT(sc, ED_P0_PSTOP, 16384 >> ED_PAGE_SHIFT);

	sc->isa16bit = 0;

	/*
	 * Write a test pattern in byte mode.  If this fails, then there
	 * probably isn't any memory at 8k - which likely means that the board
	 * is an NE2000.
	 */
	ed_pio_writemem(sc, test_pattern, 8192, sizeof(test_pattern));
	ed_pio_readmem(sc, 8192, test_buffer, sizeof(test_pattern));

	if (bcmp(test_pattern, test_buffer, sizeof(test_pattern))) {
		/* not an NE1000 - try NE2000 */

		NIC_PUT(sc, ED_P0_DCR,
		    ED_DCR_WTS | ED_DCR_FT1 | ED_DCR_LS);
		NIC_PUT(sc, ED_P0_PSTART, 16384 >> ED_PAGE_SHIFT);
		NIC_PUT(sc, ED_P0_PSTOP, 32768 >> ED_PAGE_SHIFT);

		sc->isa16bit = 1;

		/*
		 * Write a test pattern in word mode.  If this also fails, then
		 * we don't know what this board is.
		 */
		ed_pio_writemem(sc, test_pattern, 16384, sizeof(test_pattern));
		ed_pio_readmem(sc, 16384, test_buffer, sizeof(test_pattern));

		if (bcmp(test_pattern, test_buffer, sizeof(test_pattern)))
			return (0); /* not an NE2000 either */

		sc->type = ED_TYPE_NE2000;
		sc->type_str = "NE2000";
	} else {
		sc->type = ED_TYPE_NE1000;
		sc->type_str = "NE1000";
	}

	if (ia->ia_irq == IRQUNK) {
		printf("%s: %s does not have soft configuration\n",
		    sc->sc_dev.dv_xname, sc->type_str);
		return (0);
	}

	/* 8k of memory plus an additional 8k if 16-bit. */
	memsize = 8192 + sc->isa16bit * 8192;

#if 0 /* probably not useful - NE boards only come two ways */
	/* Allow kernel config file overrides. */
	if (ia->ia_msize)
		memsize = ia->ia_msize;
#endif

	/* NIC memory doesn't start at zero on an NE board. */
	/* The start address is tied to the bus width. */
	sc->mem_start = (caddr_t)(8192 + sc->isa16bit * 8192);
	sc->tx_page_start = memsize >> ED_PAGE_SHIFT;

#ifdef GWETHER
	{
		int x, i, mstart = 0;
		char pbuf0[ED_PAGE_SIZE], pbuf[ED_PAGE_SIZE], tbuf[ED_PAGE_SIZE];

		for (i = 0; i < ED_PAGE_SIZE; i++)
			pbuf0[i] = 0;

		/* Search for the start of RAM. */
		for (x = 1; x < 256; x++) {
			ed_pio_writemem(sc, pbuf0, x << ED_PAGE_SHIFT, ED_PAGE_SIZE);
			ed_pio_readmem(sc, x << ED_PAGE_SHIFT, tbuf, ED_PAGE_SIZE);
			if (!bcmp(pbuf0, tbuf, ED_PAGE_SIZE)) {
				for (i = 0; i < ED_PAGE_SIZE; i++)
					pbuf[i] = 255 - x;
				ed_pio_writemem(sc, pbuf, x << ED_PAGE_SHIFT, ED_PAGE_SIZE);
				ed_pio_readmem(sc, x << ED_PAGE_SHIFT, tbuf, ED_PAGE_SIZE);
				if (!bcmp(pbuf, tbuf, ED_PAGE_SIZE)) {
					mstart = x << ED_PAGE_SHIFT;
					memsize = ED_PAGE_SIZE;
					break;
				}
			}
		}

		if (mstart == 0) {
			printf("%s: cannot find start of RAM\n",
			    sc->sc_dev.dv_xname);
			return (0);
		}

		/* Search for the end of RAM. */
		for (++x; x < 256; x++) {
			ed_pio_writemem(sc, pbuf0, x << ED_PAGE_SHIFT, ED_PAGE_SIZE);
			ed_pio_readmem(sc, x << ED_PAGE_SHIFT, tbuf, ED_PAGE_SIZE);
			if (!bcmp(pbuf0, tbuf, ED_PAGE_SIZE)) {
				for (i = 0; i < ED_PAGE_SIZE; i++)
					pbuf[i] = 255 - x;
				ed_pio_writemem(sc, pbuf, x << ED_PAGE_SHIFT, ED_PAGE_SIZE);
				ed_pio_readmem(sc, x << ED_PAGE_SHIFT, tbuf, ED_PAGE_SIZE);
				if (!bcmp(pbuf, tbuf, ED_PAGE_SIZE))
					memsize += ED_PAGE_SIZE;
				else
					break;
			} else
				break;
		}

		printf("%s: RAM start %x, size %d\n",
		    sc->sc_dev.dv_xname, mstart, memsize);

		sc->mem_start = (caddr_t)mstart;
		sc->tx_page_start = mstart >> ED_PAGE_SHIFT;
	}
#endif /* GWETHER */

	sc->mem_size = memsize;
	sc->mem_end = sc->mem_start + memsize;

	/*
	 * Use one xmit buffer if < 16k, two buffers otherwise (if not told
	 * otherwise).
	 */
	if ((memsize < 16384) || (cf->cf_flags & ED_FLAGS_NO_MULTI_BUFFERING))
		sc->txb_cnt = 1;
	else
		sc->txb_cnt = 2;

	sc->rec_page_start = sc->tx_page_start + sc->txb_cnt * ED_TXBUF_SIZE;
	sc->rec_page_stop = sc->tx_page_start + (memsize >> ED_PAGE_SHIFT);

	sc->mem_ring =
	    sc->mem_start + ((sc->txb_cnt * ED_TXBUF_SIZE) << ED_PAGE_SHIFT);

	ed_pio_readmem(sc, 0, romdata, 16);
	for (n = 0; n < ETHER_ADDR_LEN; n++)
		sc->sc_arpcom.ac_enaddr[n] = romdata[n*(sc->isa16bit+1)];

#ifdef GWETHER
	if (sc->arpcom.ac_enaddr[2] == 0x86)
		sc->type_str = "Gateway AT";
#endif /* GWETHER */

	/* Clear any pending interrupts that might have occurred above. */
	NIC_PUT(sc, ED_P0_ISR, 0xff);

	ia->ia_iosize = ED_NOVELL_IO_PORTS;
	return (1);
}

/*
 * Install interface into kernel networking data structures.
 */
void
edattach(parent, self, aux)
	struct device *parent, *self;
	void *aux;
{
	struct ed_softc *sc = (void *)self;
	struct isa_attach_args *ia = aux;
	struct cfdata *cf = sc->sc_dev.dv_cfdata;
	struct ifnet *ifp = &sc->sc_arpcom.ac_if;

	/* Set interface to stopped condition (reset). */
	ed_stop(sc);

	/* Initialize ifnet structure. */
	ifp->if_unit = sc->sc_dev.dv_unit;
	ifp->if_name = edcd.cd_name;
	ifp->if_start = ed_start;
	ifp->if_ioctl = ed_ioctl;
	ifp->if_watchdog = ed_watchdog;
	ifp->if_flags =
	    IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS | IFF_MULTICAST;

	/*
	 * Set default state for LINK0 flag (used to disable the tranceiver
	 * for AUI operation), based on compile-time config option.
	 */
	switch (sc->vendor) {
	case ED_VENDOR_3COM:
		if (cf->cf_flags & ED_FLAGS_DISABLE_TRANCEIVER)
			ifp->if_flags |= IFF_LINK0;
		break;
	case ED_VENDOR_WD_SMC:
		if ((sc->type & ED_WD_SOFTCONFIG) == 0)
			break;
		if ((inb(sc->asic_addr + ED_WD_IRR) & ED_WD_IRR_OUT2) == 0)
			ifp->if_flags |= IFF_LINK0;
		break;
	}

	/* Attach the interface. */
	if_attach(ifp);
	ether_ifattach(ifp);

	/* Print additional info when attached. */
	printf(": address %s, ", ether_sprintf(sc->sc_arpcom.ac_enaddr));

	if (sc->type_str)
		printf("type %s ", sc->type_str);
	else
		printf("type unknown (0x%x) ", sc->type);

	printf("%s", sc->isa16bit ? "(16-bit)" : "(8-bit)");

	switch (sc->vendor) {
	case ED_VENDOR_WD_SMC:
		if ((sc->type & ED_WD_SOFTCONFIG) == 0)
			break;
	case ED_VENDOR_3COM:
		if (ifp->if_flags & IFF_LINK0)
			printf(" aui");
		else
			printf(" bnc");
		break;
	}

	printf("\n");

#if NBPFILTER > 0
	bpfattach(&ifp->if_bpf, ifp, DLT_EN10MB, sizeof(struct ether_header));
#endif

	sc->sc_ih = isa_intr_establish(ia->ia_irq, ISA_IST_EDGE, ISA_IPL_NET,
	    edintr, sc);
}

/*
 * Reset interface.
 */
void
ed_reset(sc)
	struct ed_softc *sc;
{
	int s;

	s = splimp();
	ed_stop(sc);
	ed_init(sc);
	splx(s);
}

/*
 * Take interface offline.
 */
void
ed_stop(sc)
	struct ed_softc *sc;
{
	int n = 5000;

	/* Stop everything on the interface, and select page 0 registers. */
	NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STP);

	/*
	 * Wait for interface to enter stopped state, but limit # of checks to
	 * 'n' (about 5ms).  It shouldn't even take 5us on modern DS8390's, but
	 * just in case it's an old one.
	 */
	while (((NIC_GET(sc, ED_P0_ISR) & ED_ISR_RST) == 0) && --n);
}

/*
 * Device timeout/watchdog routine.  Entered if the device neglects to generate
 * an interrupt after a transmit has been started on it.
 */
void
ed_watchdog(unit)
	int unit;
{
	struct ed_softc *sc = edcd.cd_devs[unit];

	log(LOG_ERR, "%s: device timeout\n", sc->sc_dev.dv_xname);
	++sc->sc_arpcom.ac_if.if_oerrors;

	ed_reset(sc);
}

/*
 * Initialize device.
 */
void
ed_init(sc)
	struct ed_softc *sc;
{
	struct ifnet *ifp = &sc->sc_arpcom.ac_if;
	int i;
	u_char command;
	u_long mcaf[2];

	/*
	 * Initialize the NIC in the exact order outlined in the NS manual.
	 * This init procedure is "mandatory"...don't change what or when
	 * things happen.
	 */

	/* Reset transmitter flags. */
	sc->xmit_busy = 0;
	sc->sc_arpcom.ac_if.if_timer = 0;

	sc->txb_inuse = 0;
	sc->txb_new = 0;
	sc->txb_next_tx = 0;

	/* Set interface for page 0, remote DMA complete, stopped. */
	NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STP);

	if (sc->isa16bit) {
		/*
		 * Set FIFO threshold to 8, No auto-init Remote DMA, byte
		 * order=80x86, word-wide DMA xfers,
		 */
		NIC_PUT(sc, ED_P0_DCR, ED_DCR_FT1 | ED_DCR_WTS | ED_DCR_LS);
	} else {
		/* Same as above, but byte-wide DMA xfers. */
		NIC_PUT(sc, ED_P0_DCR, ED_DCR_FT1 | ED_DCR_LS);
	}

	/* Clear remote byte count registers. */
	NIC_PUT(sc, ED_P0_RBCR0, 0);
	NIC_PUT(sc, ED_P0_RBCR1, 0);

	/* Tell RCR to do nothing for now. */
	NIC_PUT(sc, ED_P0_RCR, ED_RCR_MON);

	/* Place NIC in internal loopback mode. */
	NIC_PUT(sc, ED_P0_TCR, ED_TCR_LB0);

	/* Set lower bits of byte addressable framing to 0. */
	if (sc->is790)
		NIC_PUT(sc, 0x09, 0);

	/* Initialize receive buffer ring. */
	NIC_PUT(sc, ED_P0_BNRY, sc->rec_page_start);
	NIC_PUT(sc, ED_P0_PSTART, sc->rec_page_start);
	NIC_PUT(sc, ED_P0_PSTOP, sc->rec_page_stop);

	/*
	 * Clear all interrupts.  A '1' in each bit position clears the
	 * corresponding flag.
	 */
	NIC_PUT(sc, ED_P0_ISR, 0xff);

	/*
	 * Enable the following interrupts: receive/transmit complete,
	 * receive/transmit error, and Receiver OverWrite.
	 *
	 * Counter overflow and Remote DMA complete are *not* enabled.
	 */
	NIC_PUT(sc, ED_P0_IMR,
	    ED_IMR_PRXE | ED_IMR_PTXE | ED_IMR_RXEE | ED_IMR_TXEE |
	    ED_IMR_OVWE);

	/* Program command register for page 1. */
	NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_1 | ED_CR_STP);

	/* Copy out our station address. */
	for (i = 0; i < ETHER_ADDR_LEN; ++i)
		NIC_PUT(sc, ED_P1_PAR0 + i, sc->sc_arpcom.ac_enaddr[i]);

	/* Set multicast filter on chip. */
	ed_getmcaf(&sc->sc_arpcom, mcaf);
	for (i = 0; i < 8; i++)
		NIC_PUT(sc, ED_P1_MAR0 + i, ((u_char *)mcaf)[i]);

	/*
	 * Set current page pointer to one page after the boundary pointer, as
	 * recommended in the National manual.
	 */
	sc->next_packet = sc->rec_page_start + 1;
	NIC_PUT(sc, ED_P1_CURR, sc->next_packet);

	/* Program command register for page 0. */
	NIC_PUT(sc, ED_P1_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STP);

	i = ED_RCR_AB | ED_RCR_AM;
	if (ifp->if_flags & IFF_PROMISC) {
		/*
		 * Set promiscuous mode.  Multicast filter was set earlier so
		 * that we should receive all multicast packets.
		 */
		i |= ED_RCR_PRO | ED_RCR_AR | ED_RCR_SEP;
	}
	NIC_PUT(sc, ED_P0_RCR, i);

	/* Take interface out of loopback. */
	NIC_PUT(sc, ED_P0_TCR, 0);

	/*
	 * If this is a 3Com board, the tranceiver must be software enabled
	 * (there is no settable hardware default).
	 */
	switch (sc->vendor) {
		u_char x;
	case ED_VENDOR_3COM:
		if (ifp->if_flags & IFF_LINK0)
			outb(sc->asic_addr + ED_3COM_CR, 0);
		else
			outb(sc->asic_addr + ED_3COM_CR, ED_3COM_CR_XSEL);
		break;
	case ED_VENDOR_WD_SMC:
		if ((sc->type & ED_WD_SOFTCONFIG) == 0)
			break;
		x = inb(sc->asic_addr + ED_WD_IRR);
		if (ifp->if_flags & IFF_LINK0)
			x &= ~ED_WD_IRR_OUT2;
		else
			x |= ED_WD_IRR_OUT2;
		outb(sc->asic_addr + ED_WD_IRR, x);
		break;
	}

	/* Fire up the interface. */
	NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STA);

	/* Set 'running' flag, and clear output active flag. */
	ifp->if_flags |= IFF_RUNNING;
	ifp->if_flags &= ~IFF_OACTIVE;

	/* ...and attempt to start output. */
	ed_start(ifp);
}

/*
 * This routine actually starts the transmission on the interface.
 */
static inline void
ed_xmit(sc)
	struct ed_softc *sc;
{
	struct ifnet *ifp = &sc->sc_arpcom.ac_if;
	u_short len;

	len = sc->txb_len[sc->txb_next_tx];

	/* Set NIC for page 0 register access. */
	NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STA);

	/* Set TX buffer start page. */
	NIC_PUT(sc, ED_P0_TPSR, sc->tx_page_start +
	    sc->txb_next_tx * ED_TXBUF_SIZE);

	/* Set TX length. */
	NIC_PUT(sc, ED_P0_TBCR0, len);
	NIC_PUT(sc, ED_P0_TBCR1, len >> 8);

	/* Set page 0, remote DMA complete, transmit packet, and *start*. */
	NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_TXP | ED_CR_STA);
	sc->xmit_busy = 1;

	/* Point to next transmit buffer slot and wrap if necessary. */
	sc->txb_next_tx++;
	if (sc->txb_next_tx == sc->txb_cnt)
		sc->txb_next_tx = 0;

	/* Set a timer just in case we never hear from the board again. */
	ifp->if_timer = 2;
}

/*
 * Start output on interface.
 * We make two assumptions here:
 *  1) that the current priority is set to splimp _before_ this code
 *     is called *and* is returned to the appropriate priority after
 *     return
 *  2) that the IFF_OACTIVE flag is checked before this code is called
 *     (i.e. that the output part of the interface is idle)
 */
void
ed_start(ifp)
	struct ifnet *ifp;
{
	struct ed_softc *sc = edcd.cd_devs[ifp->if_unit];
	struct mbuf *m0, *m;
	caddr_t buffer;
	int len;

outloop:
	/*
	 * First, see if there are buffered packets and an idle transmitter -
	 * should never happen at this point.
	 */
	if (sc->txb_inuse && (sc->xmit_busy == 0)) {
		printf("%s: packets buffered, but transmitter idle\n",
		    sc->sc_dev.dv_xname);
		ed_xmit(sc);
	}

	/* See if there is room to put another packet in the buffer. */
	if (sc->txb_inuse == sc->txb_cnt) {
		/* No room.  Indicate this to the outside world and exit. */
		ifp->if_flags |= IFF_OACTIVE;
		return;
	}

	IF_DEQUEUE(&sc->sc_arpcom.ac_if.if_snd, m);
	if (m == 0) {
		/*
		 * We are using the !OACTIVE flag to indicate to the outside
		 * world that we can accept an additional packet rather than
		 * that the transmitter is _actually_ active.  Indeed, the
		 * transmitter may be active, but if we haven't filled all the
		 * buffers with data then we still want to accept more.
		 */
		ifp->if_flags &= ~IFF_OACTIVE;
		return;
	}

	/* We need to use m->m_pkthdr.len, so require the header */
	if ((m->m_flags & M_PKTHDR) == 0)
		panic("ed_start: no header mbuf");

	/* Copy the mbuf chain into the transmit buffer. */
	m0 = m;

	/* txb_new points to next open buffer slot. */
	buffer = sc->mem_start + ((sc->txb_new * ED_TXBUF_SIZE) << ED_PAGE_SHIFT);

	if (sc->mem_shared) {
		/* Special case setup for 16 bit boards... */
		switch (sc->vendor) {
		/*
		 * For 16bit 3Com boards (which have 16k of memory), we
		 * have the xmit buffers in a different page of memory
		 * ('page 0') - so change pages.
		 */
		case ED_VENDOR_3COM:
			if (sc->isa16bit)
				outb(sc->asic_addr + ED_3COM_GACFR,
				    ED_3COM_GACFR_RSEL);
			break;
		/*
		 * Enable 16bit access to shared memory on WD/SMC
		 * boards.
		 */
		case ED_VENDOR_WD_SMC:
			if (sc->isa16bit)
				outb(sc->asic_addr + ED_WD_LAAR,
				    sc->wd_laar_proto | ED_WD_LAAR_M16EN);
			outb(sc->asic_addr + ED_WD_MSR,
			    sc->wd_msr_proto | ED_WD_MSR_MENB);
			(void) inb(0x84);
			(void) inb(0x84);
			break;
		}

		for (; m; m = m->m_next) {
			bcopy(mtod(m, caddr_t), buffer, m->m_len);
			buffer += m->m_len;
		}
		len = m->m_pkthdr.len;

		/* Restore previous shared memory access. */
		switch (sc->vendor) {
		case ED_VENDOR_3COM:
			if (sc->isa16bit)
				outb(sc->asic_addr + ED_3COM_GACFR,
				    ED_3COM_GACFR_RSEL | ED_3COM_GACFR_MBS0);
			break;
		case ED_VENDOR_WD_SMC:
			outb(sc->asic_addr + ED_WD_MSR,
			    sc->wd_msr_proto);
			if (sc->isa16bit)
				outb(sc->asic_addr + ED_WD_LAAR,
				    sc->wd_laar_proto);
			(void) inb(0x84);
			(void) inb(0x84);
			break;
		}
	} else
		len = ed_pio_write_mbufs(sc, m, (long)buffer);

	sc->txb_len[sc->txb_new] = max(len, ETHER_MIN_LEN);
	sc->txb_inuse++;

	/* Point to next buffer slot and wrap if necessary. */
	if (++sc->txb_new == sc->txb_cnt)
		sc->txb_new = 0;

	if (sc->xmit_busy == 0)
		ed_xmit(sc);

#if NBPFILTER > 0
	/* Tap off here if there is a BPF listener. */
	if (sc->sc_arpcom.ac_if.if_bpf)
		bpf_mtap(sc->sc_arpcom.ac_if.if_bpf, m0);
#endif

	m_freem(m0);

	/* Loop back to the top to possibly buffer more packets. */
	goto outloop;
}

/*
 * Ethernet interface receiver interrupt.
 */
static inline void
ed_rint(sc)
	struct ed_softc *sc;
{
	u_char boundary, current;
	u_short len;
	u_char nlen;
	struct ed_ring packet_hdr;
	caddr_t packet_ptr;

loop:
	/* Set NIC to page 1 registers to get 'current' pointer. */
	NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_1 | ED_CR_STA);

	/*
	 * 'sc->next_packet' is the logical beginning of the ring-buffer - i.e.
	 * it points to where new data has been buffered.  The 'CURR' (current)
	 * register points to the logical end of the ring-buffer - i.e. it
	 * points to where additional new data will be added.  We loop here
	 * until the logical beginning equals the logical end (or in other
	 * words, until the ring-buffer is empty).
	 */
	current = NIC_GET(sc, ED_P1_CURR);
	if (sc->next_packet == current)
		return;

	/* Set NIC to page 0 registers to update boundary register. */
	NIC_PUT(sc, ED_P1_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STA);

	do {
		/* Get pointer to this buffer's header structure. */
		packet_ptr = sc->mem_ring +
		    ((sc->next_packet - sc->rec_page_start) << ED_PAGE_SHIFT);

		/*
		 * The byte count includes a 4 byte header that was added by
		 * the NIC.
		 */
		if (sc->mem_shared)
			packet_hdr = *(struct ed_ring *)packet_ptr;
		else
			ed_pio_readmem(sc, (long)packet_ptr,
			    (caddr_t) &packet_hdr, sizeof(packet_hdr));
		len = packet_hdr.count;

		/*
		 * Try do deal with old, buggy chips that sometimes duplicate
		 * the low byte of the length into the high byte.  We do this
		 * by simply ignoring the high byte of the length and always
		 * recalculating it.
		 *
		 * NOTE: sc->next_packet is pointing at the current packet.
		 */
		if (packet_hdr.next_packet >= sc->next_packet)
			nlen = (packet_hdr.next_packet - sc->next_packet);
		else
			nlen = ((packet_hdr.next_packet - sc->rec_page_start) +
				(sc->rec_page_stop - sc->next_packet));
		--nlen;
		if ((len & ED_PAGE_MASK) + sizeof(packet_hdr) > ED_PAGE_SIZE)
			--nlen;
		len = (len & ED_PAGE_MASK) | (nlen << ED_PAGE_SHIFT);
#ifdef DIAGNOSTIC
		if (len != packet_hdr.count) {
			printf("%s: length does not match next packet pointer\n",
			    sc->sc_dev.dv_xname);
			printf("%s: len %04x nlen %04x start %02x first %02x curr %02x next %02x stop %02x\n",
			    sc->sc_dev.dv_xname, packet_hdr.count, len,
			    sc->rec_page_start, sc->next_packet, current,
			    packet_hdr.next_packet, sc->rec_page_stop);
		}
#endif

		/*
		 * Be fairly liberal about what we allow as a "reasonable"
		 * length so that a [crufty] packet will make it to BPF (and
		 * can thus be analyzed).  Note that all that is really
		 * important is that we have a length that will fit into one
		 * mbuf cluster or less; the upper layer protocols can then
		 * figure out the length from their own length field(s).
		 */
		if (len <= MCLBYTES &&
		    packet_hdr.next_packet >= sc->rec_page_start &&
		    packet_hdr.next_packet < sc->rec_page_stop) {
			/* Go get packet. */
			ed_get_packet(sc, packet_ptr + sizeof(struct ed_ring),
			    len - sizeof(struct ed_ring));
			++sc->sc_arpcom.ac_if.if_ipackets;
		} else {
			/* Really BAD.  The ring pointers are corrupted. */
			log(LOG_ERR,
			    "%s: NIC memory corrupt - invalid packet length %d\n",
			    sc->sc_dev.dv_xname, len);
			++sc->sc_arpcom.ac_if.if_ierrors;
			ed_reset(sc);
			return;
		}

		/* Update next packet pointer. */
		sc->next_packet = packet_hdr.next_packet;

		/*
		 * Update NIC boundary pointer - being careful to keep it one
		 * buffer behind (as recommended by NS databook).
		 */
		boundary = sc->next_packet - 1;
		if (boundary < sc->rec_page_start)
			boundary = sc->rec_page_stop - 1;
		NIC_PUT(sc, ED_P0_BNRY, boundary);
	} while (sc->next_packet != current);

	goto loop;
}

/* Ethernet interface interrupt processor. */
int
edintr(arg)
	void *arg;
{
	struct ed_softc *sc = arg;
	u_char isr;

	/* Set NIC to page 0 registers. */
	NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STA);

	isr = NIC_GET(sc, ED_P0_ISR);
	if (!isr)
		return (0);

	/* Loop until there are no more new interrupts. */
	for (;;) {
		/*
		 * Reset all the bits that we are 'acknowledging' by writing a
		 * '1' to each bit position that was set.
		 * (Writing a '1' *clears* the bit.)
		 */
		NIC_PUT(sc, ED_P0_ISR, isr);

		/*
		 * Handle transmitter interrupts.  Handle these first because
		 * the receiver will reset the board under some conditions.
		 */
		if (isr & (ED_ISR_PTX | ED_ISR_TXE)) {
			u_char collisions = NIC_GET(sc, ED_P0_NCR) & 0x0f;

			/*
			 * Check for transmit error.  If a TX completed with an
			 * error, we end up throwing the packet away.  Really
			 * the only error that is possible is excessive
			 * collisions, and in this case it is best to allow the
			 * automatic mechanisms of TCP to backoff the flow.  Of
			 * course, with UDP we're screwed, but this is expected
			 * when a network is heavily loaded.
			 */
			(void) NIC_GET(sc, ED_P0_TSR);
			if (isr & ED_ISR_TXE) {
				/*
				 * Excessive collisions (16).
				 */
				if ((NIC_GET(sc, ED_P0_TSR) & ED_TSR_ABT)
				    && (collisions == 0)) {
					/*
					 * When collisions total 16, the P0_NCR
					 * will indicate 0, and the TSR_ABT is
					 * set.
					 */
					collisions = 16;
				}

				/* Update output errors counter. */
				++sc->sc_arpcom.ac_if.if_oerrors;
			} else {
				/*
				 * Update total number of successfully
				 * transmitted packets.
				 */
				++sc->sc_arpcom.ac_if.if_opackets;
			}

			/* Reset TX busy and output active flags. */
			sc->xmit_busy = 0;
			sc->sc_arpcom.ac_if.if_flags &= ~IFF_OACTIVE;

			/* Clear watchdog timer. */
			sc->sc_arpcom.ac_if.if_timer = 0;

			/*
			 * Add in total number of collisions on last
			 * transmission.
			 */
			sc->sc_arpcom.ac_if.if_collisions += collisions;

			/*
			 * Decrement buffer in-use count if not zero (can only
			 * be zero if a transmitter interrupt occured while not
			 * actually transmitting).
			 * If data is ready to transmit, start it transmitting,
			 * otherwise defer until after handling receiver.
			 */
			if (sc->txb_inuse && --sc->txb_inuse)
				ed_xmit(sc);
		}

		/* Handle receiver interrupts. */
		if (isr & (ED_ISR_PRX | ED_ISR_RXE | ED_ISR_OVW)) {
			/*
			 * Overwrite warning.  In order to make sure that a
			 * lockup of the local DMA hasn't occurred, we reset
			 * and re-init the NIC.  The NSC manual suggests only a
			 * partial reset/re-init is necessary - but some chips
			 * seem to want more.  The DMA lockup has been seen
			 * only with early rev chips - Methinks this bug was
			 * fixed in later revs.  -DG
			 */
			if (isr & ED_ISR_OVW) {
				++sc->sc_arpcom.ac_if.if_ierrors;
#ifdef DIAGNOSTIC
				log(LOG_WARNING,
				    "%s: warning - receiver ring buffer overrun\n",
				    sc->sc_dev.dv_xname);
#endif
				/* Stop/reset/re-init NIC. */
				ed_reset(sc);
			} else {
				/*
				 * Receiver Error.  One or more of: CRC error,
				 * frame alignment error FIFO overrun, or
				 * missed packet.
				 */
				if (isr & ED_ISR_RXE) {
					++sc->sc_arpcom.ac_if.if_ierrors;
#ifdef ED_DEBUG
					printf("%s: receive error %x\n",
					    sc->sc_dev.dv_xname,
					    NIC_GET(sc, ED_P0_RSR));
#endif
				}

				/*
				 * Go get the packet(s).
				 * XXX - Doing this on an error is dubious
				 * because there shouldn't be any data to get
				 * (we've configured the interface to not
				 * accept packets with errors).
				 */

				/*
				 * Enable 16bit access to shared memory first
				 * on WD/SMC boards.
				 */
				if (sc->vendor == ED_VENDOR_WD_SMC) {
					if (sc->isa16bit)
						outb(sc->asic_addr + ED_WD_LAAR,
						    sc->wd_laar_proto | ED_WD_LAAR_M16EN);
					outb(sc->asic_addr + ED_WD_MSR,
					    sc->wd_msr_proto | ED_WD_MSR_MENB);
					(void) inb(0x84);
					(void) inb(0x84);
				}

				ed_rint(sc);

				/* Disable 16-bit access. */
				if (sc->vendor == ED_VENDOR_WD_SMC) {
					outb(sc->asic_addr + ED_WD_MSR,
					    sc->wd_msr_proto);
					if (sc->isa16bit)
						outb(sc->asic_addr + ED_WD_LAAR,
						    sc->wd_laar_proto);
					(void) inb(0x84);
					(void) inb(0x84);
				}
			}
		}

		/*
		 * If it looks like the transmitter can take more data,	attempt
		 * to start output on the interface.  This is done after
		 * handling the receiver to give the receiver priority.
		 */
		if ((sc->sc_arpcom.ac_if.if_flags & IFF_OACTIVE) == 0)
			ed_start(&sc->sc_arpcom.ac_if);

		/*
		 * Return NIC CR to standard state: page 0, remote DMA
		 * complete, start (toggling the TXP bit off, even if was just
		 * set in the transmit routine, is *okay* - it is 'edge'
		 * triggered from low to high).
		 */
		NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STA);

		/*
		 * If the Network Talley Counters overflow, read them to reset
		 * them.  It appears that old 8390's won't clear the ISR flag
		 * otherwise - resulting in an infinite loop.
		 */
		if (isr & ED_ISR_CNT) {
			(void) NIC_GET(sc, ED_P0_CNTR0);
			(void) NIC_GET(sc, ED_P0_CNTR1);
			(void) NIC_GET(sc, ED_P0_CNTR2);
		}

		isr = NIC_GET(sc, ED_P0_ISR);
		if (!isr)
			return (1);
	}
}

/*
 * Process an ioctl request.  This code needs some work - it looks pretty ugly.
 */
int
ed_ioctl(ifp, command, data)
	register struct ifnet *ifp;
	u_long command;
	caddr_t data;
{
	struct ed_softc *sc = edcd.cd_devs[ifp->if_unit];
	register struct ifaddr *ifa = (struct ifaddr *)data;
	struct ifreq *ifr = (struct ifreq *)data;
	int s, error = 0;

	s = splimp();

	switch (command) {

	case SIOCSIFADDR:
		ifp->if_flags |= IFF_UP;

		switch (ifa->ifa_addr->sa_family) {
#ifdef INET
		case AF_INET:
			ed_init(sc);
			arp_ifinit(&sc->sc_arpcom, ifa);
			break;
#endif
#ifdef NS
		/* XXX - This code is probably wrong. */
		case AF_NS:
		    {
			register struct ns_addr *ina = &IA_SNS(ifa)->sns_addr;

			if (ns_nullhost(*ina))
				ina->x_host =
				    *(union ns_host *)(sc->sc_arpcom.ac_enaddr);
			else
				bcopy(ina->x_host.c_host,
				    sc->sc_arpcom.ac_enaddr,
				    sizeof(sc->sc_arpcom.ac_enaddr));
			/* Set new address. */
			ed_init(sc);
			break;
		    }
#endif
		default:
			ed_init(sc);
			break;
		}
		break;

	case SIOCSIFFLAGS:
		if ((ifp->if_flags & IFF_UP) == 0 &&
		    (ifp->if_flags & IFF_RUNNING) != 0) {
			/*
			 * If interface is marked down and it is running, then
			 * stop it.
			 */
			ed_stop(sc);
			ifp->if_flags &= ~IFF_RUNNING;
		} else if ((ifp->if_flags & IFF_UP) != 0 &&
		    	   (ifp->if_flags & IFF_RUNNING) == 0) {
			/*
			 * If interface is marked up and it is stopped, then
			 * start it.
			 */
			ed_init(sc);
		} else {
			/*
			 * Reset the interface to pick up changes in any other
			 * flags that affect hardware registers.
			 */
			ed_stop(sc);
			ed_init(sc);
		}
		break;

	case SIOCADDMULTI:
	case SIOCDELMULTI:
		/* Update our multicast list. */
		error = (command == SIOCADDMULTI) ?
		    ether_addmulti(ifr, &sc->sc_arpcom) :
		    ether_delmulti(ifr, &sc->sc_arpcom);

		if (error == ENETRESET) {
			/*
			 * Multicast list has changed; set the hardware filter
			 * accordingly.
			 */
			ed_stop(sc); /* XXX for ds_setmcaf? */
			ed_init(sc);
			error = 0;
		}
		break;

	default:
		error = EINVAL;
	}

	splx(s);
	return (error);
}

/*
 * Retreive packet from shared memory and send to the next level up via
 * ether_input().  If there is a BPF listener, give a copy to BPF, too.
 */
void
ed_get_packet(sc, buf, len)
	struct ed_softc *sc;
	caddr_t buf;
	u_short len;
{
	struct ether_header *eh;
    	struct mbuf *m, *ed_ring_to_mbuf();

	/* Allocate a header mbuf. */
	MGETHDR(m, M_DONTWAIT, MT_DATA);
	if (m == 0)
		return;
	m->m_pkthdr.rcvif = &sc->sc_arpcom.ac_if;
	m->m_pkthdr.len = len;
	m->m_len = 0;

	/* The following silliness is to make NFS happy. */
#define EROUND	((sizeof(struct ether_header) + 3) & ~3)
#define EOFF	(EROUND - sizeof(struct ether_header))

	/*
	 * The following assumes there is room for the ether header in the
	 * header mbuf.
	 */
	m->m_data += EOFF;
	eh = mtod(m, struct ether_header *);

	if (sc->mem_shared)
		bcopy(buf, mtod(m, caddr_t), sizeof(struct ether_header));
	else
		ed_pio_readmem(sc, (long)buf, mtod(m, caddr_t),
		    sizeof(struct ether_header));
	buf += sizeof(struct ether_header);
	m->m_len += sizeof(struct ether_header);
	len -= sizeof(struct ether_header);

	/* Pull packet off interface. */
	if (ed_ring_to_mbuf(sc, buf, m, len) == 0) {
		m_freem(m);
		return;
	}

#if NBPFILTER > 0
	/*
	 * Check if there's a BPF listener on this interface.  If so, hand off
	 * the raw packet to bpf.
	 */
	if (sc->sc_arpcom.ac_if.if_bpf) {
		bpf_mtap(sc->sc_arpcom.ac_if.if_bpf, m);

		/*
		 * Note that the interface cannot be in promiscuous mode if
		 * there are no BPF listeners.  And if we are in promiscuous
		 * mode, we have to check if this packet is really ours.
		 */
		if ((sc->sc_arpcom.ac_if.if_flags & IFF_PROMISC) &&
		    (eh->ether_dhost[0] & 1) == 0 && /* !mcast and !bcast */
		    bcmp(eh->ether_dhost, sc->sc_arpcom.ac_enaddr,
			    sizeof(eh->ether_dhost)) != 0) {
			m_freem(m);
			return;
		}
	}
#endif

	/* Fix up data start offset in mbuf to point past ether header. */
	m_adj(m, sizeof(struct ether_header));
	ether_input(&sc->sc_arpcom.ac_if, eh, m);
}

/*
 * Supporting routines.
 */

/*
 * Given a NIC memory source address and a host memory destination address,
 * copy 'amount' from NIC to host using Programmed I/O.  The 'amount' is
 * rounded up to a word - okay as long as mbufs are word sized.
 * This routine is currently Novell-specific.
 */
void
ed_pio_readmem(sc, src, dst, amount)
	struct ed_softc *sc;
	u_short src;
	caddr_t dst;
	u_short amount;
{
	/* Select page 0 registers. */
	NIC_PUT(sc, ED_P0_CR, ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STA);

	/* Round up to a word. */
	if (amount & 1)
		++amount;

	/* Set up DMA byte count. */
	NIC_PUT(sc, ED_P0_RBCR0, amount);
	NIC_PUT(sc, ED_P0_RBCR1, amount >> 8);

	/* Set up source address in NIC mem. */
	NIC_PUT(sc, ED_P0_RSAR0, src);
	NIC_PUT(sc, ED_P0_RSAR1, src >> 8);

	NIC_PUT(sc, ED_P0_CR, ED_CR_RD0 | ED_CR_PAGE_0 | ED_CR_STA);

	if (sc->isa16bit)
		insw(sc->asic_addr + ED_NOVELL_DATA, dst, amount / 2);
	else
		insb(sc->asic_addr + ED_NOVELL_DATA, dst, amount);
}

/*
 * Stripped down routine for writing a linear buffer to NIC memory.  Only used
 * in the probe routine to test the memory.  'len' must be even.
 */
void
ed_pio_writemem(sc, src, dst, len)
	struct ed_softc *sc;
	caddr_t src;
	u_short dst;
	u_short len;
{
	int maxwait = 100; /* about 120us */

	/* Select page 0 registers. */
	NIC_PUT(sc, ED_P0_CR, ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STA);

	/* Reset remote DMA complete flag. */
	NIC_PUT(sc, ED_P0_ISR, ED_ISR_RDC);

	/* Set up DMA byte count. */
	NIC_PUT(sc, ED_P0_RBCR0, len);
	NIC_PUT(sc, ED_P0_RBCR1, len >> 8);

	/* Set up destination address in NIC mem. */
	NIC_PUT(sc, ED_P0_RSAR0, dst);
	NIC_PUT(sc, ED_P0_RSAR1, dst >> 8);

	/* Set remote DMA write. */
	NIC_PUT(sc, ED_P0_CR, ED_CR_RD1 | ED_CR_PAGE_0 | ED_CR_STA);

	if (sc->isa16bit)
		outsw(sc->asic_addr + ED_NOVELL_DATA, src, len / 2);
	else
		outsb(sc->asic_addr + ED_NOVELL_DATA, src, len);

	/*
	 * Wait for remote DMA complete.  This is necessary because on the
	 * transmit side, data is handled internally by the NIC in bursts and
	 * we can't start another remote DMA until this one completes.  Not
	 * waiting causes really bad things to happen - like the NIC
	 * irrecoverably jamming the ISA bus.
	 */
	while (((NIC_GET(sc, ED_P0_ISR) & ED_ISR_RDC) != ED_ISR_RDC) && --maxwait);
}

/*
 * Write an mbuf chain to the destination NIC memory address using programmed
 * I/O.
 */
u_short
ed_pio_write_mbufs(sc, m, dst)
	struct ed_softc *sc;
	struct mbuf *m;
	u_short dst;
{
	u_short len;
	struct mbuf *mp;
	int maxwait = 100; /* about 120us */

	len = m->m_pkthdr.len;

	/* Select page 0 registers. */
	NIC_PUT(sc, ED_P0_CR, ED_CR_RD2 | ED_CR_PAGE_0 | ED_CR_STA);

	/* Reset remote DMA complete flag. */
	NIC_PUT(sc, ED_P0_ISR, ED_ISR_RDC);

	/* Set up DMA byte count. */
	NIC_PUT(sc, ED_P0_RBCR0, len);
	NIC_PUT(sc, ED_P0_RBCR1, len >> 8);

	/* Set up destination address in NIC mem. */
	NIC_PUT(sc, ED_P0_RSAR0, dst);
	NIC_PUT(sc, ED_P0_RSAR1, dst >> 8);

	/* Set remote DMA write. */
	NIC_PUT(sc, ED_P0_CR, ED_CR_RD1 | ED_CR_PAGE_0 | ED_CR_STA);

	/*
	 * Transfer the mbuf chain to the NIC memory.
	 * 16-bit cards require that data be transferred as words, and only
	 * words, so that case requires some extra code to patch over
	 * odd-length mbufs.
	 */
	if (!sc->isa16bit) {
		/* NE1000s are easy. */
		for (; m != 0; m = m->m_next) {
			if (m->m_len) {
				outsb(sc->asic_addr + ED_NOVELL_DATA,
				    mtod(m, u_char *), m->m_len);
			}
		}
	} else {
		/* NE2000s are a bit trickier. */
		u_char *data, savebyte[2];
		int len, wantbyte;

		wantbyte = 0;
		for (; m != 0; m = m->m_next) {
			len = m->m_len;
			if (len == 0)
				continue;
			data = mtod(m, u_char *);
			/* Finish the last word. */
			if (wantbyte) {
				savebyte[1] = *data;
				outw(sc->asic_addr + ED_NOVELL_DATA,
				    *(u_short *)savebyte);
				data++;
				len--;
				wantbyte = 0;
			}
			/* Output contiguous words. */
			if (len > 1)
				outsw(sc->asic_addr + ED_NOVELL_DATA,
				    data, len >> 1);
			/* Save last byte, if necessary. */
			if (len & 1) {
				data += len & ~1;
				savebyte[0] = *data;
				wantbyte = 1;
			}
		}

		if (wantbyte) {
			savebyte[1] = 0;
			outw(sc->asic_addr + ED_NOVELL_DATA,
			    *(u_short *)savebyte);
		}
	}

	/*
	 * Wait for remote DMA complete.  This is necessary because on the
	 * transmit side, data is handled internally by the NIC in bursts and
	 * we can't start another remote DMA until this one completes. 	Not
	 * waiting causes really bad things to happen - like the NIC
	 * irrecoverably jamming the ISA bus.
	 */
	while (((NIC_GET(sc, ED_P0_ISR) & ED_ISR_RDC) != ED_ISR_RDC) && --maxwait);

	if (!maxwait) {
		log(LOG_WARNING,
		    "%s: remote transmit DMA failed to complete\n",
		    sc->sc_dev.dv_xname);
		ed_reset(sc);
	}

	return (len);
}

/*
 * Given a source and destination address, copy 'amount' of a packet from the
 * ring buffer into a linear destination buffer.  Takes into account ring-wrap.
 */
static inline caddr_t
ed_ring_copy(sc, src, dst, amount)
	struct ed_softc *sc;
	caddr_t src, dst;
	u_short	amount;
{
	u_short	tmp_amount;

	/* Does copy wrap to lower addr in ring buffer? */
	if (src + amount > sc->mem_end) {
		tmp_amount = sc->mem_end - src;

		/* Copy amount up to end of NIC memory. */
		if (sc->mem_shared)
			bcopy(src, dst, tmp_amount);
		else
			ed_pio_readmem(sc, (long)src, dst, tmp_amount);

		amount -= tmp_amount;
		src = sc->mem_ring;
		dst += tmp_amount;
	}

	if (sc->mem_shared)
		bcopy(src, dst, amount);
	else
		ed_pio_readmem(sc, (long)src, dst, amount);

	return (src + amount);
}

/*
 * Copy data from receive buffer to end of mbuf chain allocate additional mbufs
 * as needed.  Return pointer to last mbuf in chain.
 * sc = ed info (softc)
 * src = pointer in ed ring buffer
 * dst = pointer to last mbuf in mbuf chain to copy to
 * amount = amount of data to copy
 */
struct mbuf *
ed_ring_to_mbuf(sc, src, dst, total_len)
	struct ed_softc *sc;
	caddr_t src;
	struct mbuf *dst;
	u_short total_len;
{
	register struct mbuf *m = dst;

	while (total_len) {
		register u_short amount = min(total_len, M_TRAILINGSPACE(m));

		if (amount == 0) {
			/*
			 * No more data in this mbuf; alloc another.
			 *
			 * If there is enough data for an mbuf cluster, attempt
			 * to allocate one of those, otherwise, a regular mbuf
			 * will do.
			 * Note that a regular mbuf is always required, even if
			 * we get a cluster - getting a cluster does not
			 * allocate any mbufs, and one is needed to assign the
			 * cluster to.  The mbuf that has a cluster extension
			 * can not be used to contain data - only the cluster
			 * can contain data.
			 */
			dst = m;
			MGET(m, M_DONTWAIT, MT_DATA);
			if (m == 0)
				return (0);

			if (total_len >= MINCLSIZE)
				MCLGET(m, M_DONTWAIT);

			m->m_len = 0;
			dst->m_next = m;
			amount = min(total_len, M_TRAILINGSPACE(m));
		}

		src = ed_ring_copy(sc, src, mtod(m, caddr_t) + m->m_len,
		    amount);

		m->m_len += amount;
		total_len -= amount;
	}
	return (m);
}

/*
 * Compute the multicast address filter from the list of multicast addresses we
 * need to listen to.
 */
void
ed_getmcaf(ac, af)
	struct arpcom *ac;
	u_long *af;
{
	struct ifnet *ifp = &ac->ac_if;
	struct ether_multi *enm;
	register u_char *cp, c;
	register u_long crc;
	register int i, len;
	struct ether_multistep step;

	/*
	 * Set up multicast address filter by passing all multicast addresses
	 * through a crc generator, and then using the high order 6 bits as an
	 * index into the 64 bit logical address filter.  The high order bit
	 * selects the word, while the rest of the bits select the bit within
	 * the word.
	 */

	if (ifp->if_flags & IFF_PROMISC) {
		ifp->if_flags |= IFF_ALLMULTI;
		af[0] = af[1] = 0xffffffff;
		return;
	}

	af[0] = af[1] = 0;
	ETHER_FIRST_MULTI(step, ac, enm);
	while (enm != NULL) {
		if (bcmp(enm->enm_addrlo, enm->enm_addrhi,
		    sizeof(enm->enm_addrlo)) != 0) {
			/*
			 * We must listen to a range of multicast addresses.
			 * For now, just accept all multicasts, rather than
			 * trying to set only those filter bits needed to match
			 * the range.  (At this time, the only use of address
			 * ranges is for IP multicast routing, for which the
			 * range is big enough to require all bits set.)
			 */
			ifp->if_flags |= IFF_ALLMULTI;
			af[0] = af[1] = 0xffffffff;
			return;
		}

		cp = enm->enm_addrlo;
		crc = 0xffffffff;
		for (len = sizeof(enm->enm_addrlo); --len >= 0;) {
			c = *cp++;
			for (i = 8; --i >= 0;) {
				if (((crc & 0x80000000) ? 1 : 0) ^ (c & 0x01)) {
					crc <<= 1;
					crc ^= 0x04c11db6 | 1;
				} else
					crc <<= 1;
				c >>= 1;
			}
		}
		/* Just want the 6 most significant bits. */
		crc >>= 26;

		/* Turn on the corresponding bit in the filter. */
		af[crc >> 5] |= 1 << ((crc & 0x1f) ^ 0);

		ETHER_NEXT_MULTI(step, enm);
	}
	ifp->if_flags &= ~IFF_ALLMULTI;
}