xref: /freebsd/sys/dev/nge/if_nge.c (revision cb2f755c7f8f45672812ecfc06fdc71084abb185)

/*
 * Copyright (c) 2001 Wind River Systems
 * Copyright (c) 1997, 1998, 1999, 2000, 2001
 *	Bill Paul <wpaul@bsdi.com>.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Bill Paul.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL Bill Paul OR THE VOICES IN HIS HEAD
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $FreeBSD$
 */

/*
 * National Semiconductor DP83820/DP83821 gigabit ethernet driver
 * for FreeBSD. Datasheets are available from:
 *
 * http://www.national.com/ds/DP/DP83820.pdf
 * http://www.national.com/ds/DP/DP83821.pdf
 *
 * These chips are used on several low cost gigabit ethernet NICs
 * sold by D-Link, Addtron, SMC and Asante. Both parts are
 * virtually the same, except the 83820 is a 64-bit/32-bit part,
 * while the 83821 is 32-bit only.
 *
 * Many cards also use National gigE transceivers, such as the
 * DP83891, DP83861 and DP83862 gigPHYTER parts. The DP83861 datasheet
 * contains a full register description that applies to all of these
 * components:
 *
 * http://www.national.com/ds/DP/DP83861.pdf
 *
 * Written by Bill Paul <wpaul@bsdi.com>
 * BSDi Open Source Solutions
 */

/*
 * The NatSemi DP83820 and 83821 controllers are enhanced versions
 * of the NatSemi MacPHYTER 10/100 devices. They support 10, 100
 * and 1000Mbps speeds with 1000baseX (ten bit interface), MII and GMII
 * ports. Other features include 8K TX FIFO and 32K RX FIFO, TCP/IP
 * hardware checksum offload (IPv4 only), VLAN tagging and filtering,
 * priority TX and RX queues, a 2048 bit multicast hash filter, 4 RX pattern
 * matching buffers, one perfect address filter buffer and interrupt
 * moderation. The 83820 supports both 64-bit and 32-bit addressing
 * and data transfers: the 64-bit support can be toggled on or off
 * via software. This affects the size of certain fields in the DMA
 * descriptors.
 *
 * There are two bugs/misfeatures in the 83820/83821 that I have
 * discovered so far:
 *
 * - Receive buffers must be aligned on 64-bit boundaries, which means
 *   you must resort to copying data in order to fix up the payload
 *   alignment.
 *
 * - In order to transmit jumbo frames larger than 8170 bytes, you have
 *   to turn off transmit checksum offloading, because the chip can't
 *   compute the checksum on an outgoing frame unless it fits entirely
 *   within the TX FIFO, which is only 8192 bytes in size. If you have
 *   TX checksum offload enabled and you transmit attempt to transmit a
 *   frame larger than 8170 bytes, the transmitter will wedge.
 *
 * To work around the latter problem, TX checksum offload is disabled
 * if the user selects an MTU larger than 8152 (8170 - 18).
 */

#include "vlan.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sockio.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/socket.h>

#include <net/if.h>
#include <net/if_arp.h>
#include <net/ethernet.h>
#include <net/if_dl.h>
#include <net/if_media.h>

#if NVLAN > 0
#include <net/if_types.h>
#include <net/if_vlan_var.h>
#endif

#include <net/bpf.h>

#include <vm/vm.h>              /* for vtophys */
#include <vm/pmap.h>            /* for vtophys */
#include <machine/clock.h>      /* for DELAY */
#include <machine/bus_pio.h>
#include <machine/bus_memio.h>
#include <machine/bus.h>
#include <machine/resource.h>
#include <sys/bus.h>
#include <sys/rman.h>

#include <dev/mii/mii.h>
#include <dev/mii/miivar.h>

#include <pci/pcireg.h>
#include <pci/pcivar.h>

#define NGE_USEIOSPACE

#include <dev/nge/if_ngereg.h>

MODULE_DEPEND(nge, miibus, 1, 1, 1);

/* "controller miibus0" required.  See GENERIC if you get errors here. */
#include "miibus_if.h"

#ifndef lint
static const char rcsid[] =
  "$FreeBSD$";
#endif

#define NGE_CSUM_FEATURES	(CSUM_IP | CSUM_TCP | CSUM_UDP)

/*
 * Various supported device vendors/types and their names.
 */
static struct nge_type nge_devs[] = {
	{ NGE_VENDORID, NGE_DEVICEID,
	    "National Semiconductor Gigabit Ethernet" },
	{ 0, 0, NULL }
};

static int nge_probe		__P((device_t));
static int nge_attach		__P((device_t));
static int nge_detach		__P((device_t));

static int nge_alloc_jumbo_mem	__P((struct nge_softc *));
static void nge_free_jumbo_mem	__P((struct nge_softc *));
static void *nge_jalloc		__P((struct nge_softc *));
static void nge_jfree		__P((caddr_t, void *));

static int nge_newbuf		__P((struct nge_softc *,
					struct nge_desc *,
					struct mbuf *));
static int nge_encap		__P((struct nge_softc *,
					struct mbuf *, u_int32_t *));
static void nge_rxeof		__P((struct nge_softc *));
static void nge_rxeoc		__P((struct nge_softc *));
static void nge_txeof		__P((struct nge_softc *));
static void nge_intr		__P((void *));
static void nge_tick		__P((void *));
static void nge_start		__P((struct ifnet *));
static int nge_ioctl		__P((struct ifnet *, u_long, caddr_t));
static void nge_init		__P((void *));
static void nge_stop		__P((struct nge_softc *));
static void nge_watchdog		__P((struct ifnet *));
static void nge_shutdown		__P((device_t));
static int nge_ifmedia_upd	__P((struct ifnet *));
static void nge_ifmedia_sts	__P((struct ifnet *, struct ifmediareq *));

static void nge_delay		__P((struct nge_softc *));
static void nge_eeprom_idle	__P((struct nge_softc *));
static void nge_eeprom_putbyte	__P((struct nge_softc *, int));
static void nge_eeprom_getword	__P((struct nge_softc *, int, u_int16_t *));
static void nge_read_eeprom	__P((struct nge_softc *, caddr_t, int,
							int, int));

static void nge_mii_sync	__P((struct nge_softc *));
static void nge_mii_send	__P((struct nge_softc *, u_int32_t, int));
static int nge_mii_readreg	__P((struct nge_softc *,
					struct nge_mii_frame *));
static int nge_mii_writereg	__P((struct nge_softc *,
					struct nge_mii_frame *));

static int nge_miibus_readreg	__P((device_t, int, int));
static int nge_miibus_writereg	__P((device_t, int, int, int));
static void nge_miibus_statchg	__P((device_t));

static void nge_setmulti	__P((struct nge_softc *));
static u_int32_t nge_crc	__P((struct nge_softc *, caddr_t));
static void nge_reset		__P((struct nge_softc *));
static int nge_list_rx_init	__P((struct nge_softc *));
static int nge_list_tx_init	__P((struct nge_softc *));

#ifdef NGE_USEIOSPACE
#define NGE_RES			SYS_RES_IOPORT
#define NGE_RID			NGE_PCI_LOIO
#else
#define NGE_RES			SYS_RES_MEMORY
#define NGE_RID			NGE_PCI_LOMEM
#endif

static device_method_t nge_methods[] = {
	/* Device interface */
	DEVMETHOD(device_probe,		nge_probe),
	DEVMETHOD(device_attach,	nge_attach),
	DEVMETHOD(device_detach,	nge_detach),
	DEVMETHOD(device_shutdown,	nge_shutdown),

	/* bus interface */
	DEVMETHOD(bus_print_child,	bus_generic_print_child),
	DEVMETHOD(bus_driver_added,	bus_generic_driver_added),

	/* MII interface */
	DEVMETHOD(miibus_readreg,	nge_miibus_readreg),
	DEVMETHOD(miibus_writereg,	nge_miibus_writereg),
	DEVMETHOD(miibus_statchg,	nge_miibus_statchg),

	{ 0, 0 }
};

static driver_t nge_driver = {
	"nge",
	nge_methods,
	sizeof(struct nge_softc)
};

static devclass_t nge_devclass;

DRIVER_MODULE(if_nge, pci, nge_driver, nge_devclass, 0, 0);
DRIVER_MODULE(miibus, nge, miibus_driver, miibus_devclass, 0, 0);

#define NGE_SETBIT(sc, reg, x)				\
	CSR_WRITE_4(sc, reg,				\
		CSR_READ_4(sc, reg) | (x))

#define NGE_CLRBIT(sc, reg, x)				\
	CSR_WRITE_4(sc, reg,				\
		CSR_READ_4(sc, reg) & ~(x))

#define SIO_SET(x)					\
	CSR_WRITE_4(sc, NGE_MEAR, CSR_READ_4(sc, NGE_MEAR) | x)

#define SIO_CLR(x)					\
	CSR_WRITE_4(sc, NGE_MEAR, CSR_READ_4(sc, NGE_MEAR) & ~x)

static void nge_delay(sc)
	struct nge_softc	*sc;
{
	int			idx;

	for (idx = (300 / 33) + 1; idx > 0; idx--)
		CSR_READ_4(sc, NGE_CSR);

	return;
}

static void nge_eeprom_idle(sc)
	struct nge_softc	*sc;
{
	register int		i;

	SIO_SET(NGE_MEAR_EE_CSEL);
	nge_delay(sc);
	SIO_SET(NGE_MEAR_EE_CLK);
	nge_delay(sc);

	for (i = 0; i < 25; i++) {
		SIO_CLR(NGE_MEAR_EE_CLK);
		nge_delay(sc);
		SIO_SET(NGE_MEAR_EE_CLK);
		nge_delay(sc);
	}

	SIO_CLR(NGE_MEAR_EE_CLK);
	nge_delay(sc);
	SIO_CLR(NGE_MEAR_EE_CSEL);
	nge_delay(sc);
	CSR_WRITE_4(sc, NGE_MEAR, 0x00000000);

	return;
}

/*
 * Send a read command and address to the EEPROM, check for ACK.
 */
static void nge_eeprom_putbyte(sc, addr)
	struct nge_softc	*sc;
	int			addr;
{
	register int		d, i;

	d = addr | NGE_EECMD_READ;

	/*
	 * Feed in each bit and stobe the clock.
	 */
	for (i = 0x400; i; i >>= 1) {
		if (d & i) {
			SIO_SET(NGE_MEAR_EE_DIN);
		} else {
			SIO_CLR(NGE_MEAR_EE_DIN);
		}
		nge_delay(sc);
		SIO_SET(NGE_MEAR_EE_CLK);
		nge_delay(sc);
		SIO_CLR(NGE_MEAR_EE_CLK);
		nge_delay(sc);
	}

	return;
}

/*
 * Read a word of data stored in the EEPROM at address 'addr.'
 */
static void nge_eeprom_getword(sc, addr, dest)
	struct nge_softc	*sc;
	int			addr;
	u_int16_t		*dest;
{
	register int		i;
	u_int16_t		word = 0;

	/* Force EEPROM to idle state. */
	nge_eeprom_idle(sc);

	/* Enter EEPROM access mode. */
	nge_delay(sc);
	SIO_CLR(NGE_MEAR_EE_CLK);
	nge_delay(sc);
	SIO_SET(NGE_MEAR_EE_CSEL);
	nge_delay(sc);

	/*
	 * Send address of word we want to read.
	 */
	nge_eeprom_putbyte(sc, addr);

	/*
	 * Start reading bits from EEPROM.
	 */
	for (i = 0x8000; i; i >>= 1) {
		SIO_SET(NGE_MEAR_EE_CLK);
		nge_delay(sc);
		if (CSR_READ_4(sc, NGE_MEAR) & NGE_MEAR_EE_DOUT)
			word |= i;
		nge_delay(sc);
		SIO_CLR(NGE_MEAR_EE_CLK);
		nge_delay(sc);
	}

	/* Turn off EEPROM access mode. */
	nge_eeprom_idle(sc);

	*dest = word;

	return;
}

/*
 * Read a sequence of words from the EEPROM.
 */
static void nge_read_eeprom(sc, dest, off, cnt, swap)
	struct nge_softc	*sc;
	caddr_t			dest;
	int			off;
	int			cnt;
	int			swap;
{
	int			i;
	u_int16_t		word = 0, *ptr;

	for (i = 0; i < cnt; i++) {
		nge_eeprom_getword(sc, off + i, &word);
		ptr = (u_int16_t *)(dest + (i * 2));
		if (swap)
			*ptr = ntohs(word);
		else
			*ptr = word;
	}

	return;
}

/*
 * Sync the PHYs by setting data bit and strobing the clock 32 times.
 */
static void nge_mii_sync(sc)
	struct nge_softc		*sc;
{
	register int		i;

	SIO_SET(NGE_MEAR_MII_DIR|NGE_MEAR_MII_DATA);

	for (i = 0; i < 32; i++) {
		SIO_SET(NGE_MEAR_MII_CLK);
		DELAY(1);
		SIO_CLR(NGE_MEAR_MII_CLK);
		DELAY(1);
	}

	return;
}

/*
 * Clock a series of bits through the MII.
 */
static void nge_mii_send(sc, bits, cnt)
	struct nge_softc		*sc;
	u_int32_t		bits;
	int			cnt;
{
	int			i;

	SIO_CLR(NGE_MEAR_MII_CLK);

	for (i = (0x1 << (cnt - 1)); i; i >>= 1) {
                if (bits & i) {
			SIO_SET(NGE_MEAR_MII_DATA);
                } else {
			SIO_CLR(NGE_MEAR_MII_DATA);
                }
		DELAY(1);
		SIO_CLR(NGE_MEAR_MII_CLK);
		DELAY(1);
		SIO_SET(NGE_MEAR_MII_CLK);
	}
}

/*
 * Read an PHY register through the MII.
 */
static int nge_mii_readreg(sc, frame)
	struct nge_softc		*sc;
	struct nge_mii_frame	*frame;

{
	int			i, ack, s;

	s = splimp();

	/*
	 * Set up frame for RX.
	 */
	frame->mii_stdelim = NGE_MII_STARTDELIM;
	frame->mii_opcode = NGE_MII_READOP;
	frame->mii_turnaround = 0;
	frame->mii_data = 0;

	CSR_WRITE_4(sc, NGE_MEAR, 0);

	/*
 	 * Turn on data xmit.
	 */
	SIO_SET(NGE_MEAR_MII_DIR);

	nge_mii_sync(sc);

	/*
	 * Send command/address info.
	 */
	nge_mii_send(sc, frame->mii_stdelim, 2);
	nge_mii_send(sc, frame->mii_opcode, 2);
	nge_mii_send(sc, frame->mii_phyaddr, 5);
	nge_mii_send(sc, frame->mii_regaddr, 5);

	/* Idle bit */
	SIO_CLR((NGE_MEAR_MII_CLK|NGE_MEAR_MII_DATA));
	DELAY(1);
	SIO_SET(NGE_MEAR_MII_CLK);
	DELAY(1);

	/* Turn off xmit. */
	SIO_CLR(NGE_MEAR_MII_DIR);
	/* Check for ack */
	SIO_CLR(NGE_MEAR_MII_CLK);
	DELAY(1);
	SIO_SET(NGE_MEAR_MII_CLK);
	DELAY(1);
	ack = CSR_READ_4(sc, NGE_MEAR) & NGE_MEAR_MII_DATA;

	/*
	 * Now try reading data bits. If the ack failed, we still
	 * need to clock through 16 cycles to keep the PHY(s) in sync.
	 */
	if (ack) {
		for(i = 0; i < 16; i++) {
			SIO_CLR(NGE_MEAR_MII_CLK);
			DELAY(1);
			SIO_SET(NGE_MEAR_MII_CLK);
			DELAY(1);
		}
		goto fail;
	}

	for (i = 0x8000; i; i >>= 1) {
		SIO_CLR(NGE_MEAR_MII_CLK);
		DELAY(1);
		if (!ack) {
			if (CSR_READ_4(sc, NGE_MEAR) & NGE_MEAR_MII_DATA)
				frame->mii_data |= i;
			DELAY(1);
		}
		SIO_SET(NGE_MEAR_MII_CLK);
		DELAY(1);
	}

fail:

	SIO_CLR(NGE_MEAR_MII_CLK);
	DELAY(1);
	SIO_SET(NGE_MEAR_MII_CLK);
	DELAY(1);

	splx(s);

	if (ack)
		return(1);
	return(0);
}

/*
 * Write to a PHY register through the MII.
 */
static int nge_mii_writereg(sc, frame)
	struct nge_softc		*sc;
	struct nge_mii_frame	*frame;

{
	int			s;

	s = splimp();
	/*
	 * Set up frame for TX.
	 */

	frame->mii_stdelim = NGE_MII_STARTDELIM;
	frame->mii_opcode = NGE_MII_WRITEOP;
	frame->mii_turnaround = NGE_MII_TURNAROUND;

	/*
 	 * Turn on data output.
	 */
	SIO_SET(NGE_MEAR_MII_DIR);

	nge_mii_sync(sc);

	nge_mii_send(sc, frame->mii_stdelim, 2);
	nge_mii_send(sc, frame->mii_opcode, 2);
	nge_mii_send(sc, frame->mii_phyaddr, 5);
	nge_mii_send(sc, frame->mii_regaddr, 5);
	nge_mii_send(sc, frame->mii_turnaround, 2);
	nge_mii_send(sc, frame->mii_data, 16);

	/* Idle bit. */
	SIO_SET(NGE_MEAR_MII_CLK);
	DELAY(1);
	SIO_CLR(NGE_MEAR_MII_CLK);
	DELAY(1);

	/*
	 * Turn off xmit.
	 */
	SIO_CLR(NGE_MEAR_MII_DIR);

	splx(s);

	return(0);
}

static int nge_miibus_readreg(dev, phy, reg)
	device_t		dev;
	int			phy, reg;
{
	struct nge_softc	*sc;
	struct nge_mii_frame	frame;

	sc = device_get_softc(dev);

	bzero((char *)&frame, sizeof(frame));

	frame.mii_phyaddr = phy;
	frame.mii_regaddr = reg;
	nge_mii_readreg(sc, &frame);

	return(frame.mii_data);
}

static int nge_miibus_writereg(dev, phy, reg, data)
	device_t		dev;
	int			phy, reg, data;
{
	struct nge_softc	*sc;
	struct nge_mii_frame	frame;

	sc = device_get_softc(dev);

	bzero((char *)&frame, sizeof(frame));

	frame.mii_phyaddr = phy;
	frame.mii_regaddr = reg;
	frame.mii_data = data;
	nge_mii_writereg(sc, &frame);

	return(0);
}

static void nge_miibus_statchg(dev)
	device_t		dev;
{
	struct nge_softc	*sc;
	struct mii_data		*mii;

	sc = device_get_softc(dev);
	mii = device_get_softc(sc->nge_miibus);

	if ((mii->mii_media_active & IFM_GMASK) == IFM_FDX) {
		NGE_SETBIT(sc, NGE_TX_CFG,
		    (NGE_TXCFG_IGN_HBEAT|NGE_TXCFG_IGN_CARR));
		NGE_SETBIT(sc, NGE_RX_CFG, NGE_RXCFG_RX_FDX);
	} else {
		NGE_CLRBIT(sc, NGE_TX_CFG,
		    (NGE_TXCFG_IGN_HBEAT|NGE_TXCFG_IGN_CARR));
		NGE_CLRBIT(sc, NGE_RX_CFG, NGE_RXCFG_RX_FDX);
	}

	return;
}

static u_int32_t nge_crc(sc, addr)
	struct nge_softc	*sc;
	caddr_t			addr;
{
	u_int32_t		crc, carry;
	int			i, j;
	u_int8_t		c;

	/* Compute CRC for the address value. */
	crc = 0xFFFFFFFF; /* initial value */

	for (i = 0; i < 6; i++) {
		c = *(addr + i);
		for (j = 0; j < 8; j++) {
			carry = ((crc & 0x80000000) ? 1 : 0) ^ (c & 0x01);
			crc <<= 1;
			c >>= 1;
			if (carry)
				crc = (crc ^ 0x04c11db6) | carry;
		}
	}

	/*
	 * return the filter bit position
	 */

	return((crc >> 21) & 0x00000FFF);
}

static void nge_setmulti(sc)
	struct nge_softc	*sc;
{
	struct ifnet		*ifp;
	struct ifmultiaddr	*ifma;
	u_int32_t		h = 0, i, filtsave;
	int			bit, index;

	ifp = &sc->arpcom.ac_if;

	if (ifp->if_flags & IFF_ALLMULTI || ifp->if_flags & IFF_PROMISC) {
		NGE_CLRBIT(sc, NGE_RXFILT_CTL,
		    NGE_RXFILTCTL_MCHASH|NGE_RXFILTCTL_UCHASH);
		NGE_SETBIT(sc, NGE_RXFILT_CTL, NGE_RXFILTCTL_ALLMULTI);
		return;
	}

	/*
	 * We have to explicitly enable the multicast hash table
	 * on the NatSemi chip if we want to use it, which we do.
	 * We also have to tell it that we don't want to use the
	 * hash table for matching unicast addresses.
	 */
	NGE_SETBIT(sc, NGE_RXFILT_CTL, NGE_RXFILTCTL_MCHASH);
	NGE_CLRBIT(sc, NGE_RXFILT_CTL,
	    NGE_RXFILTCTL_ALLMULTI|NGE_RXFILTCTL_UCHASH);

	filtsave = CSR_READ_4(sc, NGE_RXFILT_CTL);

	/* first, zot all the existing hash bits */
	for (i = 0; i < NGE_MCAST_FILTER_LEN; i += 2) {
		CSR_WRITE_4(sc, NGE_RXFILT_CTL, NGE_FILTADDR_MCAST_LO + i);
		CSR_WRITE_4(sc, NGE_RXFILT_DATA, 0);
	}

	/*
	 * From the 11 bits returned by the crc routine, the top 7
	 * bits represent the 16-bit word in the mcast hash table
	 * that needs to be updated, and the lower 4 bits represent
	 * which bit within that byte needs to be set.
	 */
	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
		if (ifma->ifma_addr->sa_family != AF_LINK)
			continue;
		h = nge_crc(sc, LLADDR((struct sockaddr_dl *)ifma->ifma_addr));
		index = (h >> 4) & 0x7F;
		bit = h & 0xF;
		CSR_WRITE_4(sc, NGE_RXFILT_CTL,
		    NGE_FILTADDR_MCAST_LO + (index * 2));
		NGE_SETBIT(sc, NGE_RXFILT_DATA, (1 << bit));
	}

	CSR_WRITE_4(sc, NGE_RXFILT_CTL, filtsave);

	return;
}

static void nge_reset(sc)
	struct nge_softc	*sc;
{
	register int		i;

	NGE_SETBIT(sc, NGE_CSR, NGE_CSR_RESET);

	for (i = 0; i < NGE_TIMEOUT; i++) {
		if (!(CSR_READ_4(sc, NGE_CSR) & NGE_CSR_RESET))
			break;
	}

	if (i == NGE_TIMEOUT)
		printf("nge%d: reset never completed\n", sc->nge_unit);

	/* Wait a little while for the chip to get its brains in order. */
	DELAY(1000);

	/*
	 * If this is a NetSemi chip, make sure to clear
	 * PME mode.
	 */
	CSR_WRITE_4(sc, NGE_CLKRUN, NGE_CLKRUN_PMESTS);
	CSR_WRITE_4(sc, NGE_CLKRUN, 0);

        return;
}

/*
 * Probe for an NatSemi chip. Check the PCI vendor and device
 * IDs against our list and return a device name if we find a match.
 */
static int nge_probe(dev)
	device_t		dev;
{
	struct nge_type		*t;

	t = nge_devs;

	while(t->nge_name != NULL) {
		if ((pci_get_vendor(dev) == t->nge_vid) &&
		    (pci_get_device(dev) == t->nge_did)) {
			device_set_desc(dev, t->nge_name);
			return(0);
		}
		t++;
	}

	return(ENXIO);
}

/*
 * Attach the interface. Allocate softc structures, do ifmedia
 * setup and ethernet/BPF attach.
 */
static int nge_attach(dev)
	device_t		dev;
{
	int			s;
	u_char			eaddr[ETHER_ADDR_LEN];
	u_int32_t		command;
	struct nge_softc	*sc;
	struct ifnet		*ifp;
	int			unit, error = 0, rid;

	s = splimp();

	sc = device_get_softc(dev);
	unit = device_get_unit(dev);
	bzero(sc, sizeof(struct nge_softc));

	mtx_init(&sc->nge_mtx, device_get_nameunit(dev), MTX_DEF|MTX_RECURSE);

	/*
	 * Handle power management nonsense.
	 */
	if (pci_get_powerstate(dev) != PCI_POWERSTATE_D0) {
		u_int32_t		iobase, membase, irq;

		/* Save important PCI config data. */
		iobase = pci_read_config(dev, NGE_PCI_LOIO, 4);
		membase = pci_read_config(dev, NGE_PCI_LOMEM, 4);
		irq = pci_read_config(dev, NGE_PCI_INTLINE, 4);

		/* Reset the power state. */
		printf("nge%d: chip is in D%d power mode "
		    "-- setting to D0\n", unit,
		    pci_get_powerstate(dev));
		pci_set_powerstate(dev, PCI_POWERSTATE_D0);

		/* Restore PCI config data. */
		pci_write_config(dev, NGE_PCI_LOIO, iobase, 4);
		pci_write_config(dev, NGE_PCI_LOMEM, membase, 4);
		pci_write_config(dev, NGE_PCI_INTLINE, irq, 4);
	}

	/*
	 * Map control/status registers.
	 */
	pci_enable_busmaster(dev);
	pci_enable_io(dev, PCIM_CMD_PORTEN);
	pci_enable_io(dev, PCIM_CMD_MEMEN);
	command = pci_read_config(dev, PCIR_COMMAND, 4);

#ifdef NGE_USEIOSPACE
	if (!(command & PCIM_CMD_PORTEN)) {
		printf("nge%d: failed to enable I/O ports!\n", unit);
		error = ENXIO;;
		goto fail;
	}
#else
	if (!(command & PCIM_CMD_MEMEN)) {
		printf("nge%d: failed to enable memory mapping!\n", unit);
		error = ENXIO;;
		goto fail;
	}
#endif

	rid = NGE_RID;
	sc->nge_res = bus_alloc_resource(dev, NGE_RES, &rid,
	    0, ~0, 1, RF_ACTIVE);

	if (sc->nge_res == NULL) {
		printf("nge%d: couldn't map ports/memory\n", unit);
		error = ENXIO;
		goto fail;
	}

	sc->nge_btag = rman_get_bustag(sc->nge_res);
	sc->nge_bhandle = rman_get_bushandle(sc->nge_res);

	/* Allocate interrupt */
	rid = 0;
	sc->nge_irq = bus_alloc_resource(dev, SYS_RES_IRQ, &rid, 0, ~0, 1,
	    RF_SHAREABLE | RF_ACTIVE);

	if (sc->nge_irq == NULL) {
		printf("nge%d: couldn't map interrupt\n", unit);
		bus_release_resource(dev, NGE_RES, NGE_RID, sc->nge_res);
		error = ENXIO;
		goto fail;
	}

	error = bus_setup_intr(dev, sc->nge_irq, INTR_TYPE_NET,
	    nge_intr, sc, &sc->nge_intrhand);

	if (error) {
		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->nge_irq);
		bus_release_resource(dev, NGE_RES, NGE_RID, sc->nge_res);
		printf("nge%d: couldn't set up irq\n", unit);
		goto fail;
	}

	/* Reset the adapter. */
	nge_reset(sc);

	/*
	 * Get station address from the EEPROM.
	 */
	nge_read_eeprom(sc, (caddr_t)&eaddr[4], NGE_EE_NODEADDR, 1, 0);
	nge_read_eeprom(sc, (caddr_t)&eaddr[2], NGE_EE_NODEADDR + 1, 1, 0);
	nge_read_eeprom(sc, (caddr_t)&eaddr[0], NGE_EE_NODEADDR + 2, 1, 0);

	/*
	 * A NatSemi chip was detected. Inform the world.
	 */
	printf("nge%d: Ethernet address: %6D\n", unit, eaddr, ":");

	sc->nge_unit = unit;
	bcopy(eaddr, (char *)&sc->arpcom.ac_enaddr, ETHER_ADDR_LEN);

	sc->nge_ldata = contigmalloc(sizeof(struct nge_list_data), M_DEVBUF,
	    M_NOWAIT, 0, 0xffffffff, PAGE_SIZE, 0);

	if (sc->nge_ldata == NULL) {
		printf("nge%d: no memory for list buffers!\n", unit);
		bus_teardown_intr(dev, sc->nge_irq, sc->nge_intrhand);
		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->nge_irq);
		bus_release_resource(dev, NGE_RES, NGE_RID, sc->nge_res);
		error = ENXIO;
		goto fail;
	}
	bzero(sc->nge_ldata, sizeof(struct nge_list_data));

	/* Try to allocate memory for jumbo buffers. */
	if (nge_alloc_jumbo_mem(sc)) {
		printf("nge%d: jumbo buffer allocation failed\n",
                    sc->nge_unit);
		contigfree(sc->nge_ldata,
		    sizeof(struct nge_list_data), M_DEVBUF);
		bus_teardown_intr(dev, sc->nge_irq, sc->nge_intrhand);
		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->nge_irq);
		bus_release_resource(dev, NGE_RES, NGE_RID, sc->nge_res);
		error = ENXIO;
		goto fail;
	}

	ifp = &sc->arpcom.ac_if;
	ifp->if_softc = sc;
	ifp->if_unit = unit;
	ifp->if_name = "nge";
	ifp->if_mtu = ETHERMTU;
	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
	ifp->if_ioctl = nge_ioctl;
	ifp->if_output = ether_output;
	ifp->if_start = nge_start;
	ifp->if_watchdog = nge_watchdog;
	ifp->if_init = nge_init;
	ifp->if_baudrate = 1000000000;
	ifp->if_snd.ifq_maxlen = NGE_TX_LIST_CNT - 1;
	ifp->if_hwassist = NGE_CSUM_FEATURES;

	/*
	 * Do MII setup.
	 */
	if (mii_phy_probe(dev, &sc->nge_miibus,
	    nge_ifmedia_upd, nge_ifmedia_sts)) {
		printf("nge%d: MII without any PHY!\n", sc->nge_unit);
		nge_free_jumbo_mem(sc);
		bus_teardown_intr(dev, sc->nge_irq, sc->nge_intrhand);
		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->nge_irq);
		bus_release_resource(dev, NGE_RES, NGE_RID, sc->nge_res);
		error = ENXIO;
		goto fail;
	}

	/*
	 * Call MI attach routine.
	 */
	ether_ifattach(ifp, ETHER_BPF_SUPPORTED);
	callout_handle_init(&sc->nge_stat_ch);

fail:
	splx(s);
	mtx_destroy(&sc->nge_mtx);
	return(error);
}

static int nge_detach(dev)
	device_t		dev;
{
	struct nge_softc	*sc;
	struct ifnet		*ifp;
	int			s;

	s = splimp();

	sc = device_get_softc(dev);
	ifp = &sc->arpcom.ac_if;

	nge_reset(sc);
	nge_stop(sc);
	ether_ifdetach(ifp, ETHER_BPF_SUPPORTED);

	bus_generic_detach(dev);
	device_delete_child(dev, sc->nge_miibus);

	bus_teardown_intr(dev, sc->nge_irq, sc->nge_intrhand);
	bus_release_resource(dev, SYS_RES_IRQ, 0, sc->nge_irq);
	bus_release_resource(dev, NGE_RES, NGE_RID, sc->nge_res);

	contigfree(sc->nge_ldata, sizeof(struct nge_list_data), M_DEVBUF);
	nge_free_jumbo_mem(sc);

	splx(s);
	mtx_destroy(&sc->nge_mtx);

	return(0);
}

/*
 * Initialize the transmit descriptors.
 */
static int nge_list_tx_init(sc)
	struct nge_softc	*sc;
{
	struct nge_list_data	*ld;
	struct nge_ring_data	*cd;
	int			i;

	cd = &sc->nge_cdata;
	ld = sc->nge_ldata;

	for (i = 0; i < NGE_TX_LIST_CNT; i++) {
		if (i == (NGE_TX_LIST_CNT - 1)) {
			ld->nge_tx_list[i].nge_nextdesc =
			    &ld->nge_tx_list[0];
			ld->nge_tx_list[i].nge_next =
			    vtophys(&ld->nge_tx_list[0]);
		} else {
			ld->nge_tx_list[i].nge_nextdesc =
			    &ld->nge_tx_list[i + 1];
			ld->nge_tx_list[i].nge_next =
			    vtophys(&ld->nge_tx_list[i + 1]);
		}
		ld->nge_tx_list[i].nge_mbuf = NULL;
		ld->nge_tx_list[i].nge_ptr = 0;
		ld->nge_tx_list[i].nge_ctl = 0;
	}

	cd->nge_tx_prod = cd->nge_tx_cons = cd->nge_tx_cnt = 0;

	return(0);
}


/*
 * Initialize the RX descriptors and allocate mbufs for them. Note that
 * we arrange the descriptors in a closed ring, so that the last descriptor
 * points back to the first.
 */
static int nge_list_rx_init(sc)
	struct nge_softc	*sc;
{
	struct nge_list_data	*ld;
	struct nge_ring_data	*cd;
	int			i;

	ld = sc->nge_ldata;
	cd = &sc->nge_cdata;

	for (i = 0; i < NGE_RX_LIST_CNT; i++) {
		if (nge_newbuf(sc, &ld->nge_rx_list[i], NULL) == ENOBUFS)
			return(ENOBUFS);
		if (i == (NGE_RX_LIST_CNT - 1)) {
			ld->nge_rx_list[i].nge_nextdesc =
			    &ld->nge_rx_list[0];
			ld->nge_rx_list[i].nge_next =
			    vtophys(&ld->nge_rx_list[0]);
		} else {
			ld->nge_rx_list[i].nge_nextdesc =
			    &ld->nge_rx_list[i + 1];
			ld->nge_rx_list[i].nge_next =
			    vtophys(&ld->nge_rx_list[i + 1]);
		}
	}

	cd->nge_rx_prod = 0;

	return(0);
}

/*
 * Initialize an RX descriptor and attach an MBUF cluster.
 */
static int nge_newbuf(sc, c, m)
	struct nge_softc	*sc;
	struct nge_desc		*c;
	struct mbuf		*m;
{
	struct mbuf		*m_new = NULL;
	caddr_t			*buf = NULL;

	if (m == NULL) {
		MGETHDR(m_new, M_DONTWAIT, MT_DATA);
		if (m_new == NULL) {
			printf("nge%d: no memory for rx list "
			    "-- packet dropped!\n", sc->nge_unit);
			return(ENOBUFS);
		}

		/* Allocate the jumbo buffer */
		buf = nge_jalloc(sc);
		if (buf == NULL) {
#ifdef NGE_VERBOSE
			printf("nge%d: jumbo allocation failed "
			    "-- packet dropped!\n", sc->nge_unit);
#endif
			m_freem(m_new);
			return(ENOBUFS);
		}
		/* Attach the buffer to the mbuf */
		m_new->m_data = (void *)buf;
		m_new->m_len = m_new->m_pkthdr.len = NGE_MCLBYTES;
		MEXTADD(m_new, buf, NGE_MCLBYTES, nge_jfree,
		    (struct nge_softc *)sc, 0, EXT_NET_DRV);
	} else {
		m_new = m;
		m_new->m_len = m_new->m_pkthdr.len = NGE_MCLBYTES;
		m_new->m_data = m_new->m_ext.ext_buf;
	}

	m_adj(m_new, sizeof(u_int64_t));

	c->nge_mbuf = m_new;
	c->nge_ptr = vtophys(mtod(m_new, caddr_t));
	c->nge_ctl = m_new->m_len;
	c->nge_extsts = 0;

	return(0);
}

static int nge_alloc_jumbo_mem(sc)
	struct nge_softc	*sc;
{
	caddr_t			ptr;
	register int		i;
	struct nge_jpool_entry   *entry;

	/* Grab a big chunk o' storage. */
	sc->nge_cdata.nge_jumbo_buf = contigmalloc(NGE_JMEM, M_DEVBUF,
	    M_NOWAIT, 0, 0xffffffff, PAGE_SIZE, 0);

	if (sc->nge_cdata.nge_jumbo_buf == NULL) {
		printf("nge%d: no memory for jumbo buffers!\n", sc->nge_unit);
		return(ENOBUFS);
	}

	SLIST_INIT(&sc->nge_jfree_listhead);
	SLIST_INIT(&sc->nge_jinuse_listhead);

	/*
	 * Now divide it up into 9K pieces and save the addresses
	 * in an array.
	 */
	ptr = sc->nge_cdata.nge_jumbo_buf;
	for (i = 0; i < NGE_JSLOTS; i++) {
		sc->nge_cdata.nge_jslots[i] = ptr;
		ptr += NGE_MCLBYTES;
		entry = malloc(sizeof(struct nge_jpool_entry),
		    M_DEVBUF, M_NOWAIT);
		if (entry == NULL) {
			free(sc->nge_cdata.nge_jumbo_buf, M_DEVBUF);
			sc->nge_cdata.nge_jumbo_buf = NULL;
			printf("nge%d: no memory for jumbo "
			    "buffer queue!\n", sc->nge_unit);
			return(ENOBUFS);
		}
		entry->slot = i;
		SLIST_INSERT_HEAD(&sc->nge_jfree_listhead,
		    entry, jpool_entries);
	}

	return(0);
}

static void nge_free_jumbo_mem(sc)
	struct nge_softc	*sc;
{
	register int		i;
	struct nge_jpool_entry   *entry;

	for (i = 0; i < NGE_JSLOTS; i++) {
		entry = SLIST_FIRST(&sc->nge_jfree_listhead);
		free(entry, M_DEVBUF);
		SLIST_REMOVE_HEAD(&sc->nge_jfree_listhead, jpool_entries);
	}

	contigfree(sc->nge_cdata.nge_jumbo_buf, NGE_JMEM, M_DEVBUF);

	return;
}

/*
 * Allocate a jumbo buffer.
 */
static void *nge_jalloc(sc)
	struct nge_softc	*sc;
{
	struct nge_jpool_entry   *entry;

	entry = SLIST_FIRST(&sc->nge_jfree_listhead);

	if (entry == NULL) {
#ifdef NGE_VERBOSE
		printf("nge%d: no free jumbo buffers\n", sc->nge_unit);
#endif
		return(NULL);
	}

	SLIST_REMOVE_HEAD(&sc->nge_jfree_listhead, jpool_entries);
	SLIST_INSERT_HEAD(&sc->nge_jinuse_listhead, entry, jpool_entries);
	return(sc->nge_cdata.nge_jslots[entry->slot]);
}

/*
 * Release a jumbo buffer.
 */
static void nge_jfree(buf, args)
	caddr_t			buf;
	void			*args;
{
	struct nge_softc	*sc;
	int		        i;
	struct nge_jpool_entry   *entry;

	/* Extract the softc struct pointer. */
	sc = args;

	if (sc == NULL)
		panic("nge_jfree: can't find softc pointer!");

	/* calculate the slot this buffer belongs to */
	i = ((vm_offset_t)buf
	     - (vm_offset_t)sc->nge_cdata.nge_jumbo_buf) / NGE_JLEN;

	if ((i < 0) || (i >= NGE_JSLOTS))
		panic("nge_jfree: asked to free buffer that we don't manage!");

	entry = SLIST_FIRST(&sc->nge_jinuse_listhead);
	if (entry == NULL)
		panic("nge_jfree: buffer not in use!");
	entry->slot = i;
	SLIST_REMOVE_HEAD(&sc->nge_jinuse_listhead, jpool_entries);
	SLIST_INSERT_HEAD(&sc->nge_jfree_listhead, entry, jpool_entries);

	return;
}
/*
 * A frame has been uploaded: pass the resulting mbuf chain up to
 * the higher level protocols.
 */
static void nge_rxeof(sc)
	struct nge_softc	*sc;
{
        struct ether_header	*eh;
        struct mbuf		*m;
        struct ifnet		*ifp;
	struct nge_desc		*cur_rx;
	int			i, total_len = 0;
	u_int32_t		rxstat;

	ifp = &sc->arpcom.ac_if;
	i = sc->nge_cdata.nge_rx_prod;

	while(NGE_OWNDESC(&sc->nge_ldata->nge_rx_list[i])) {
		struct mbuf		*m0 = NULL;
		u_int32_t		extsts;

		cur_rx = &sc->nge_ldata->nge_rx_list[i];
		rxstat = cur_rx->nge_rxstat;
		extsts = cur_rx->nge_extsts;
		m = cur_rx->nge_mbuf;
		cur_rx->nge_mbuf = NULL;
		total_len = NGE_RXBYTES(cur_rx);
		NGE_INC(i, NGE_RX_LIST_CNT);

		/*
		 * If an error occurs, update stats, clear the
		 * status word and leave the mbuf cluster in place:
		 * it should simply get re-used next time this descriptor
	 	 * comes up in the ring.
		 */
		if (!(rxstat & NGE_CMDSTS_PKT_OK)) {
			ifp->if_ierrors++;
			nge_newbuf(sc, cur_rx, m);
			continue;
		}


		/*
		 * Ok. NatSemi really screwed up here. This is the
		 * only gigE chip I know of with alignment constraints
		 * on receive buffers. RX buffers must be 64-bit aligned.
		 */
		m0 = m_devget(mtod(m, char *) - ETHER_ALIGN,
		    total_len + ETHER_ALIGN, 0, ifp, NULL);
		nge_newbuf(sc, cur_rx, m);
		if (m0 == NULL) {
			printf("nge%d: no receive buffers "
			    "available -- packet dropped!\n",
			    sc->nge_unit);
			ifp->if_ierrors++;
			continue;
		}
		m_adj(m0, ETHER_ALIGN);
		m = m0;

		ifp->if_ipackets++;
		eh = mtod(m, struct ether_header *);

		/* Remove header from mbuf and pass it on. */
		m_adj(m, sizeof(struct ether_header));

		/* Do IP checksum checking. */
		if (extsts & NGE_RXEXTSTS_IPPKT)
			m->m_pkthdr.csum_flags |= CSUM_IP_CHECKED;
		if (!(extsts & NGE_RXEXTSTS_IPCSUMERR))
			m->m_pkthdr.csum_flags |= CSUM_IP_VALID;
		if ((extsts & NGE_RXEXTSTS_TCPPKT &&
		    !(extsts & NGE_RXEXTSTS_TCPCSUMERR)) ||
		    (extsts & NGE_RXEXTSTS_UDPPKT &&
		    !(extsts & NGE_RXEXTSTS_UDPCSUMERR))) {
			m->m_pkthdr.csum_flags |=
			    CSUM_DATA_VALID|CSUM_PSEUDO_HDR;
			m->m_pkthdr.csum_data = 0xffff;
		}

#if NVLAN > 0
		/*
		 * If we received a packet with a vlan tag, pass it
		 * to vlan_input() instead of ether_input().
		 */
		if (extsts & NGE_RXEXTSTS_VLANPKT) {
			vlan_input_tag(eh, m, extsts & NGE_RXEXTSTS_VTCI);
                        continue;
                }
#endif

		ether_input(ifp, eh, m);
	}

	sc->nge_cdata.nge_rx_prod = i;

	return;
}

void nge_rxeoc(sc)
	struct nge_softc	*sc;
{
	struct ifnet		*ifp;

	ifp = &sc->arpcom.ac_if;
	nge_rxeof(sc);
	ifp->if_flags &= ~IFF_RUNNING;
	nge_init(sc);
	return;
}

/*
 * A frame was downloaded to the chip. It's safe for us to clean up
 * the list buffers.
 */

static void nge_txeof(sc)
	struct nge_softc	*sc;
{
	struct nge_desc		*cur_tx = NULL;
	struct ifnet		*ifp;
	u_int32_t		idx;

	ifp = &sc->arpcom.ac_if;

	/* Clear the timeout timer. */
	ifp->if_timer = 0;

	/*
	 * Go through our tx list and free mbufs for those
	 * frames that have been transmitted.
	 */
	idx = sc->nge_cdata.nge_tx_cons;
	while (idx != sc->nge_cdata.nge_tx_prod) {
		cur_tx = &sc->nge_ldata->nge_tx_list[idx];

		if (NGE_OWNDESC(cur_tx))
			break;

		if (cur_tx->nge_ctl & NGE_CMDSTS_MORE) {
			sc->nge_cdata.nge_tx_cnt--;
			NGE_INC(idx, NGE_TX_LIST_CNT);
			continue;
		}

		if (!(cur_tx->nge_ctl & NGE_CMDSTS_PKT_OK)) {
			ifp->if_oerrors++;
			if (cur_tx->nge_txstat & NGE_TXSTAT_EXCESSCOLLS)
				ifp->if_collisions++;
			if (cur_tx->nge_txstat & NGE_TXSTAT_OUTOFWINCOLL)
				ifp->if_collisions++;
		}

		ifp->if_collisions +=
		    (cur_tx->nge_txstat & NGE_TXSTAT_COLLCNT) >> 16;

		ifp->if_opackets++;
		if (cur_tx->nge_mbuf != NULL) {
			m_freem(cur_tx->nge_mbuf);
			cur_tx->nge_mbuf = NULL;
		}

		sc->nge_cdata.nge_tx_cnt--;
		NGE_INC(idx, NGE_TX_LIST_CNT);
		ifp->if_timer = 0;
	}

	sc->nge_cdata.nge_tx_cons = idx;

	if (cur_tx != NULL)
		ifp->if_flags &= ~IFF_OACTIVE;

	return;
}

static void nge_tick(xsc)
	void			*xsc;
{
	struct nge_softc	*sc;
	struct mii_data		*mii;
	struct ifnet		*ifp;
	int			s;

	s = splimp();

	sc = xsc;
	ifp = &sc->arpcom.ac_if;

	mii = device_get_softc(sc->nge_miibus);
	mii_tick(mii);

	if (!sc->nge_link) {
		mii_pollstat(mii);
		if (mii->mii_media_status & IFM_ACTIVE &&
		    IFM_SUBTYPE(mii->mii_media_active) != IFM_NONE) {
			sc->nge_link++;
			if (IFM_SUBTYPE(mii->mii_media_active) == IFM_1000_TX)
				printf("nge%d: gigabit link up\n",
				    sc->nge_unit);
			if (ifp->if_snd.ifq_head != NULL)
				nge_start(ifp);
		} else
			sc->nge_stat_ch = timeout(nge_tick, sc, hz);
	}


	splx(s);

	return;
}

static void nge_intr(arg)
	void			*arg;
{
	struct nge_softc	*sc;
	struct ifnet		*ifp;
	u_int32_t		status;

	sc = arg;
	ifp = &sc->arpcom.ac_if;

	/* Supress unwanted interrupts */
	if (!(ifp->if_flags & IFF_UP)) {
		nge_stop(sc);
		return;
	}

	/* Disable interrupts. */
	CSR_WRITE_4(sc, NGE_IER, 0);

	for (;;) {
		/* Reading the ISR register clears all interrupts. */
		status = CSR_READ_4(sc, NGE_ISR);

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

		if ((status & NGE_ISR_TX_DESC_OK) ||
		    (status & NGE_ISR_TX_ERR) ||
		    (status & NGE_ISR_TX_OK) ||
		    (status & NGE_ISR_TX_IDLE))
			nge_txeof(sc);

		if ((status & NGE_ISR_RX_DESC_OK) ||
		    (status & NGE_ISR_RX_OK))
			nge_rxeof(sc);

		if ((status & NGE_ISR_RX_ERR) ||
		    (status & NGE_ISR_RX_OFLOW)) {
			nge_rxeoc(sc);
		}

		if (status & NGE_ISR_SYSERR) {
			nge_reset(sc);
			ifp->if_flags &= ~IFF_RUNNING;
			nge_init(sc);
		}

		if (status & NGE_IMR_PHY_INTR) {
			sc->nge_link = 0;
			nge_tick(sc);
		}
	}

	/* Re-enable interrupts. */
	CSR_WRITE_4(sc, NGE_IER, 1);

	if (ifp->if_snd.ifq_head != NULL)
		nge_start(ifp);

	return;
}

/*
 * Encapsulate an mbuf chain in a descriptor by coupling the mbuf data
 * pointers to the fragment pointers.
 */
static int nge_encap(sc, m_head, txidx)
	struct nge_softc	*sc;
	struct mbuf		*m_head;
	u_int32_t		*txidx;
{
	struct nge_desc		*f = NULL;
	struct mbuf		*m;
	int			frag, cur, cnt = 0;
#if NVLAN > 0
	struct ifvlan		*ifv = NULL;

	if ((m_head->m_flags & (M_PROTO1|M_PKTHDR)) == (M_PROTO1|M_PKTHDR) &&
	    m_head->m_pkthdr.rcvif != NULL &&
	    m_head->m_pkthdr.rcvif->if_type == IFT_8021_VLAN)
		ifv = m_head->m_pkthdr.rcvif->if_softc;
#endif

	/*
 	 * Start packing the mbufs in this chain into
	 * the fragment pointers. Stop when we run out
 	 * of fragments or hit the end of the mbuf chain.
	 */
	m = m_head;
	cur = frag = *txidx;

	for (m = m_head; m != NULL; m = m->m_next) {
		if (m->m_len != 0) {
			if ((NGE_TX_LIST_CNT -
			    (sc->nge_cdata.nge_tx_cnt + cnt)) < 2)
				return(ENOBUFS);
			f = &sc->nge_ldata->nge_tx_list[frag];
			f->nge_ctl = NGE_CMDSTS_MORE | m->m_len;
			f->nge_ptr = vtophys(mtod(m, vm_offset_t));
			if (cnt != 0)
				f->nge_ctl |= NGE_CMDSTS_OWN;
			cur = frag;
			NGE_INC(frag, NGE_TX_LIST_CNT);
			cnt++;
		}
	}

	if (m != NULL)
		return(ENOBUFS);

	sc->nge_ldata->nge_tx_list[*txidx].nge_extsts = 0;
	if (m_head->m_pkthdr.csum_flags) {
		if (m_head->m_pkthdr.csum_flags & CSUM_IP)
			sc->nge_ldata->nge_tx_list[*txidx].nge_extsts |=
			    NGE_TXEXTSTS_IPCSUM;
		if (m_head->m_pkthdr.csum_flags & CSUM_TCP)
			sc->nge_ldata->nge_tx_list[*txidx].nge_extsts |=
			    NGE_TXEXTSTS_TCPCSUM;
		if (m_head->m_pkthdr.csum_flags & CSUM_UDP)
			sc->nge_ldata->nge_tx_list[*txidx].nge_extsts |=
			    NGE_TXEXTSTS_UDPCSUM;
	}

#if NVLAN > 0
	if (ifv != NULL) {
		sc->nge_ldata->nge_tx_list[cur].nge_extsts |=
			(NGE_TXEXTSTS_VLANPKT|ifv->ifv_tag);
	}
#endif

	sc->nge_ldata->nge_tx_list[cur].nge_mbuf = m_head;
	sc->nge_ldata->nge_tx_list[cur].nge_ctl &= ~NGE_CMDSTS_MORE;
	sc->nge_ldata->nge_tx_list[*txidx].nge_ctl |= NGE_CMDSTS_OWN;
	sc->nge_cdata.nge_tx_cnt += cnt;
	*txidx = frag;

	return(0);
}

/*
 * Main transmit routine. To avoid having to do mbuf copies, we put pointers
 * to the mbuf data regions directly in the transmit lists. We also save a
 * copy of the pointers since the transmit list fragment pointers are
 * physical addresses.
 */

static void nge_start(ifp)
	struct ifnet		*ifp;
{
	struct nge_softc	*sc;
	struct mbuf		*m_head = NULL;
	u_int32_t		idx;

	sc = ifp->if_softc;

	if (!sc->nge_link)
		return;

	idx = sc->nge_cdata.nge_tx_prod;

	if (ifp->if_flags & IFF_OACTIVE)
		return;

	while(sc->nge_ldata->nge_tx_list[idx].nge_mbuf == NULL) {
		IF_DEQUEUE(&ifp->if_snd, m_head);
		if (m_head == NULL)
			break;

		if (nge_encap(sc, m_head, &idx)) {
			IF_PREPEND(&ifp->if_snd, m_head);
			ifp->if_flags |= IFF_OACTIVE;
			break;
		}

		/*
		 * If there's a BPF listener, bounce a copy of this frame
		 * to him.
		 */
		if (ifp->if_bpf)
			bpf_mtap(ifp, m_head);

	}

	/* Transmit */
	sc->nge_cdata.nge_tx_prod = idx;
	NGE_SETBIT(sc, NGE_CSR, NGE_CSR_TX_ENABLE);

	/*
	 * Set a timeout in case the chip goes out to lunch.
	 */
	ifp->if_timer = 5;

	return;
}

static void nge_init(xsc)
	void			*xsc;
{
	struct nge_softc	*sc = xsc;
	struct ifnet		*ifp = &sc->arpcom.ac_if;
	struct mii_data		*mii;
	int			s;

	if (ifp->if_flags & IFF_RUNNING)
		return;

	s = splimp();

	/*
	 * Cancel pending I/O and free all RX/TX buffers.
	 */
	nge_stop(sc);

	mii = device_get_softc(sc->nge_miibus);

	/* Set MAC address */
	CSR_WRITE_4(sc, NGE_RXFILT_CTL, NGE_FILTADDR_PAR0);
	CSR_WRITE_4(sc, NGE_RXFILT_DATA,
	    ((u_int16_t *)sc->arpcom.ac_enaddr)[0]);
	CSR_WRITE_4(sc, NGE_RXFILT_CTL, NGE_FILTADDR_PAR1);
	CSR_WRITE_4(sc, NGE_RXFILT_DATA,
	    ((u_int16_t *)sc->arpcom.ac_enaddr)[1]);
	CSR_WRITE_4(sc, NGE_RXFILT_CTL, NGE_FILTADDR_PAR2);
	CSR_WRITE_4(sc, NGE_RXFILT_DATA,
	    ((u_int16_t *)sc->arpcom.ac_enaddr)[2]);

	/* Init circular RX list. */
	if (nge_list_rx_init(sc) == ENOBUFS) {
		printf("nge%d: initialization failed: no "
			"memory for rx buffers\n", sc->nge_unit);
		nge_stop(sc);
		(void)splx(s);
		return;
	}

	/*
	 * Init tx descriptors.
	 */
	nge_list_tx_init(sc);

	/*
	 * For the NatSemi chip, we have to explicitly enable the
	 * reception of ARP frames, as well as turn on the 'perfect
	 * match' filter where we store the station address, otherwise
	 * we won't receive unicasts meant for this host.
	 */
	NGE_SETBIT(sc, NGE_RXFILT_CTL, NGE_RXFILTCTL_ARP);
	NGE_SETBIT(sc, NGE_RXFILT_CTL, NGE_RXFILTCTL_PERFECT);

	 /* If we want promiscuous mode, set the allframes bit. */
	if (ifp->if_flags & IFF_PROMISC) {
		NGE_SETBIT(sc, NGE_RXFILT_CTL, NGE_RXFILTCTL_ALLPHYS);
	} else {
		NGE_CLRBIT(sc, NGE_RXFILT_CTL, NGE_RXFILTCTL_ALLPHYS);
	}

	/*
	 * Set the capture broadcast bit to capture broadcast frames.
	 */
	if (ifp->if_flags & IFF_BROADCAST) {
		NGE_SETBIT(sc, NGE_RXFILT_CTL, NGE_RXFILTCTL_BROAD);
	} else {
		NGE_CLRBIT(sc, NGE_RXFILT_CTL, NGE_RXFILTCTL_BROAD);
	}

	/*
	 * Load the multicast filter.
	 */
	nge_setmulti(sc);

	/* Turn the receive filter on */
	NGE_SETBIT(sc, NGE_RXFILT_CTL, NGE_RXFILTCTL_ENABLE);

	/*
	 * Load the address of the RX and TX lists.
	 */
	CSR_WRITE_4(sc, NGE_RX_LISTPTR,
	    vtophys(&sc->nge_ldata->nge_rx_list[0]));
	CSR_WRITE_4(sc, NGE_TX_LISTPTR,
	    vtophys(&sc->nge_ldata->nge_tx_list[0]));

	/* Set RX configuration */
	CSR_WRITE_4(sc, NGE_RX_CFG, NGE_RXCFG);
	/*
	 * Enable hardware checksum validation for all IPv4
	 * packets, do not reject packets with bad checksums.
	 */
	CSR_WRITE_4(sc, NGE_VLAN_IP_RXCTL, NGE_VIPRXCTL_IPCSUM_ENB);

#if NVLAN > 0
	/*
	 * If VLAN support is enabled, tell the chip to detect
	 * and strip VLAN tag info from received frames. The tag
	 * will be provided in the extsts field in the RX descriptors.
	 */
	NGE_SETBIT(sc, NGE_VLAN_IP_RXCTL,
	    NGE_VIPRXCTL_TAG_DETECT_ENB|NGE_VIPRXCTL_TAG_STRIP_ENB);
#endif

	/* Set TX configuration */
	CSR_WRITE_4(sc, NGE_TX_CFG, NGE_TXCFG);

	/*
	 * Enable TX IPv4 checksumming on a per-packet basis.
	 */
	CSR_WRITE_4(sc, NGE_VLAN_IP_TXCTL, NGE_VIPTXCTL_CSUM_PER_PKT);

#if NVLAN > 0
	/*
	 * If VLAN support is enabled, tell the chip to insert
	 * VLAN tags on a per-packet basis as dictated by the
	 * code in the frame encapsulation routine.
	 */
	NGE_SETBIT(sc, NGE_VLAN_IP_TXCTL, NGE_VIPTXCTL_TAG_PER_PKT);
#endif

	/* Set full/half duplex mode. */
	if ((mii->mii_media_active & IFM_GMASK) == IFM_FDX) {
		NGE_SETBIT(sc, NGE_TX_CFG,
		    (NGE_TXCFG_IGN_HBEAT|NGE_TXCFG_IGN_CARR));
		NGE_SETBIT(sc, NGE_RX_CFG, NGE_RXCFG_RX_FDX);
	} else {
		NGE_CLRBIT(sc, NGE_TX_CFG,
		    (NGE_TXCFG_IGN_HBEAT|NGE_TXCFG_IGN_CARR));
		NGE_CLRBIT(sc, NGE_RX_CFG, NGE_RXCFG_RX_FDX);
	}

	/*
	 * Enable the delivery of PHY interrupts based on
	 * link/speed/duplex status changes. Also enable the
	 * extsts field in the DMA descriptors (needed for
	 * TCP/IP checksum offload on transmit).
	 */
	NGE_SETBIT(sc, NGE_CFG, NGE_CFG_PHYINTR_SPD|NGE_CFG_MODE_1000|
	    NGE_CFG_PHYINTR_LNK|NGE_CFG_PHYINTR_DUP|NGE_CFG_EXTSTS_ENB);

	/*
	 * Enable interrupts.
	 */
	CSR_WRITE_4(sc, NGE_IMR, NGE_INTRS);
	CSR_WRITE_4(sc, NGE_IER, 1);

	/* Enable receiver and transmitter. */
	NGE_CLRBIT(sc, NGE_CSR, NGE_CSR_TX_DISABLE|NGE_CSR_RX_DISABLE);
	NGE_SETBIT(sc, NGE_CSR, NGE_CSR_RX_ENABLE);

	nge_ifmedia_upd(ifp);

	ifp->if_flags |= IFF_RUNNING;
	ifp->if_flags &= ~IFF_OACTIVE;

	(void)splx(s);

	return;
}

/*
 * Set media options.
 */
static int nge_ifmedia_upd(ifp)
	struct ifnet		*ifp;
{
	struct nge_softc	*sc;
	struct mii_data		*mii;

	sc = ifp->if_softc;

	mii = device_get_softc(sc->nge_miibus);
	sc->nge_link = 0;
	if (mii->mii_instance) {
		struct mii_softc	*miisc;
		for (miisc = LIST_FIRST(&mii->mii_phys); miisc != NULL;
		    miisc = LIST_NEXT(miisc, mii_list))
			mii_phy_reset(miisc);
	}
	mii_mediachg(mii);

	return(0);
}

/*
 * Report current media status.
 */
static void nge_ifmedia_sts(ifp, ifmr)
	struct ifnet		*ifp;
	struct ifmediareq	*ifmr;
{
	struct nge_softc	*sc;
	struct mii_data		*mii;

	sc = ifp->if_softc;

	mii = device_get_softc(sc->nge_miibus);
	mii_pollstat(mii);
	ifmr->ifm_active = mii->mii_media_active;
	ifmr->ifm_status = mii->mii_media_status;

	return;
}

static int nge_ioctl(ifp, command, data)
	struct ifnet		*ifp;
	u_long			command;
	caddr_t			data;
{
	struct nge_softc	*sc = ifp->if_softc;
	struct ifreq		*ifr = (struct ifreq *) data;
	struct mii_data		*mii;
	int			s, error = 0;

	s = splimp();

	switch(command) {
	case SIOCSIFADDR:
	case SIOCGIFADDR:
		error = ether_ioctl(ifp, command, data);
		break;
	case SIOCSIFMTU:
		if (ifr->ifr_mtu > NGE_JUMBO_MTU)
			error = EINVAL;
		else {
			ifp->if_mtu = ifr->ifr_mtu;
			/*
			 * Workaround: if the MTU is larger than
			 * 8152 (TX FIFO size minus 64 minus 18), turn off
			 * TX checksum offloading.
			 */
			if (ifr->ifr_mtu == 8152)
				ifp->if_hwassist = 0;
			else
				ifp->if_hwassist = NGE_CSUM_FEATURES;
		}
		break;
	case SIOCSIFFLAGS:
		if (ifp->if_flags & IFF_UP) {
			if (ifp->if_flags & IFF_RUNNING &&
			    ifp->if_flags & IFF_PROMISC &&
			    !(sc->nge_if_flags & IFF_PROMISC)) {
				NGE_SETBIT(sc, NGE_RXFILT_CTL,
				    NGE_RXFILTCTL_ALLPHYS|
				    NGE_RXFILTCTL_ALLMULTI);
			} else if (ifp->if_flags & IFF_RUNNING &&
			    !(ifp->if_flags & IFF_PROMISC) &&
			    sc->nge_if_flags & IFF_PROMISC) {
				NGE_CLRBIT(sc, NGE_RXFILT_CTL,
				    NGE_RXFILTCTL_ALLPHYS);
				if (!(ifp->if_flags & IFF_ALLMULTI))
					NGE_CLRBIT(sc, NGE_RXFILT_CTL,
					    NGE_RXFILTCTL_ALLMULTI);
			} else {
				ifp->if_flags &= ~IFF_RUNNING;
				nge_init(sc);
			}
		} else {
			if (ifp->if_flags & IFF_RUNNING)
				nge_stop(sc);
		}
		sc->nge_if_flags = ifp->if_flags;
		error = 0;
		break;
	case SIOCADDMULTI:
	case SIOCDELMULTI:
		nge_setmulti(sc);
		error = 0;
		break;
	case SIOCGIFMEDIA:
	case SIOCSIFMEDIA:
		mii = device_get_softc(sc->nge_miibus);
		error = ifmedia_ioctl(ifp, ifr, &mii->mii_media, command);
		break;
	default:
		error = EINVAL;
		break;
	}

	(void)splx(s);

	return(error);
}

static void nge_watchdog(ifp)
	struct ifnet		*ifp;
{
	struct nge_softc	*sc;

	sc = ifp->if_softc;

	ifp->if_oerrors++;
	printf("nge%d: watchdog timeout\n", sc->nge_unit);

	nge_stop(sc);
	nge_reset(sc);
	ifp->if_flags &= ~IFF_RUNNING;
	nge_init(sc);

	if (ifp->if_snd.ifq_head != NULL)
		nge_start(ifp);

	return;
}

/*
 * Stop the adapter and free any mbufs allocated to the
 * RX and TX lists.
 */
static void nge_stop(sc)
	struct nge_softc	*sc;
{
	register int		i;
	struct ifnet		*ifp;
	struct ifmedia_entry	*ifm;
	struct mii_data		*mii;
	int			mtmp, itmp;

	ifp = &sc->arpcom.ac_if;
	ifp->if_timer = 0;
	mii = device_get_softc(sc->nge_miibus);

	untimeout(nge_tick, sc, sc->nge_stat_ch);
	CSR_WRITE_4(sc, NGE_IER, 0);
	CSR_WRITE_4(sc, NGE_IMR, 0);
	NGE_SETBIT(sc, NGE_CSR, NGE_CSR_TX_DISABLE|NGE_CSR_RX_DISABLE);
	DELAY(1000);
	CSR_WRITE_4(sc, NGE_TX_LISTPTR, 0);
	CSR_WRITE_4(sc, NGE_RX_LISTPTR, 0);

	/*
	 * Isolate/power down the PHY, but leave the media selection
	 * unchanged so that things will be put back to normal when
	 * we bring the interface back up.
	 */
	itmp = ifp->if_flags;
	ifp->if_flags |= IFF_UP;
	ifm = mii->mii_media.ifm_cur;
	mtmp = ifm->ifm_media;
	ifm->ifm_media = IFM_ETHER|IFM_NONE;
	mii_mediachg(mii);
	ifm->ifm_media = mtmp;
	ifp->if_flags = itmp;

	sc->nge_link = 0;

	/*
	 * Free data in the RX lists.
	 */
	for (i = 0; i < NGE_RX_LIST_CNT; i++) {
		if (sc->nge_ldata->nge_rx_list[i].nge_mbuf != NULL) {
			m_freem(sc->nge_ldata->nge_rx_list[i].nge_mbuf);
			sc->nge_ldata->nge_rx_list[i].nge_mbuf = NULL;
		}
	}
	bzero((char *)&sc->nge_ldata->nge_rx_list,
		sizeof(sc->nge_ldata->nge_rx_list));

	/*
	 * Free the TX list buffers.
	 */
	for (i = 0; i < NGE_TX_LIST_CNT; i++) {
		if (sc->nge_ldata->nge_tx_list[i].nge_mbuf != NULL) {
			m_freem(sc->nge_ldata->nge_tx_list[i].nge_mbuf);
			sc->nge_ldata->nge_tx_list[i].nge_mbuf = NULL;
		}
	}

	bzero((char *)&sc->nge_ldata->nge_tx_list,
		sizeof(sc->nge_ldata->nge_tx_list));

	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);

	return;
}

/*
 * Stop all chip I/O so that the kernel's probe routines don't
 * get confused by errant DMAs when rebooting.
 */
static void nge_shutdown(dev)
	device_t		dev;
{
	struct nge_softc	*sc;

	sc = device_get_softc(dev);

	nge_reset(sc);
	nge_stop(sc);

	return;
}