xref: /src/sys/dev/ic/i82557.c

/*	$NetBSD: i82557.c,v 1.47 2001/05/21 21:47:52 thorpej Exp $	*/

/*-
 * Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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 the NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 THE FOUNDATION OR CONTRIBUTORS
 * 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.
 */

/*
 * Copyright (c) 1995, David Greenman
 * 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 unmodified, 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 THE AUTHOR OR CONTRIBUTORS 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.
 *
 *	Id: if_fxp.c,v 1.47 1998/01/08 23:42:29 eivind Exp
 */

/*
 * Device driver for the Intel i82557 fast Ethernet controller,
 * and its successors, the i82558 and i82559.
 */

#include "opt_inet.h"
#include "opt_ns.h"
#include "bpfilter.h"
#include "rnd.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/device.h>

#include <machine/endian.h>

#include <uvm/uvm_extern.h>

#if NRND > 0
#include <sys/rnd.h>
#endif

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <net/if_ether.h>

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

#ifdef INET
#include <netinet/in.h>
#include <netinet/if_inarp.h>
#endif

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

#include <machine/bus.h>
#include <machine/intr.h>

#include <dev/mii/miivar.h>

#include <dev/ic/i82557reg.h>
#include <dev/ic/i82557var.h>

/*
 * NOTE!  On the Alpha, we have an alignment constraint.  The
 * card DMAs the packet immediately following the RFA.  However,
 * the first thing in the packet is a 14-byte Ethernet header.
 * This means that the packet is misaligned.  To compensate,
 * we actually offset the RFA 2 bytes into the cluster.  This
 * alignes the packet after the Ethernet header at a 32-bit
 * boundary.  HOWEVER!  This means that the RFA is misaligned!
 */
#define	RFA_ALIGNMENT_FUDGE	2

/*
 * Template for default configuration parameters.
 * See struct fxp_cb_config for the bit definitions.
 */
u_int8_t fxp_cb_config_template[] = {
	0x0, 0x0,		/* cb_status */
	0x80, 0x2,		/* cb_command */
	0xff, 0xff, 0xff, 0xff,	/* link_addr */
	0x16,	/*  0 */
	0x8,	/*  1 */
	0x0,	/*  2 */
	0x0,	/*  3 */
	0x0,	/*  4 */
	0x80,	/*  5 */
	0xb2,	/*  6 */
	0x3,	/*  7 */
	0x1,	/*  8 */
	0x0,	/*  9 */
	0x26,	/* 10 */
	0x0,	/* 11 */
	0x60,	/* 12 */
	0x0,	/* 13 */
	0xf2,	/* 14 */
	0x48,	/* 15 */
	0x0,	/* 16 */
	0x40,	/* 17 */
	0xf3,	/* 18 */
	0x0,	/* 19 */
	0x3f,	/* 20 */
	0x5	/* 21 */
};

void	fxp_mii_initmedia(struct fxp_softc *);
int	fxp_mii_mediachange(struct ifnet *);
void	fxp_mii_mediastatus(struct ifnet *, struct ifmediareq *);

void	fxp_80c24_initmedia(struct fxp_softc *);
int	fxp_80c24_mediachange(struct ifnet *);
void	fxp_80c24_mediastatus(struct ifnet *, struct ifmediareq *);

void	fxp_start(struct ifnet *);
int	fxp_ioctl(struct ifnet *, u_long, caddr_t);
void	fxp_watchdog(struct ifnet *);
int	fxp_init(struct ifnet *);
void	fxp_stop(struct ifnet *, int);

void	fxp_rxdrain(struct fxp_softc *);
int	fxp_add_rfabuf(struct fxp_softc *, bus_dmamap_t, int);
int	fxp_mdi_read(struct device *, int, int);
void	fxp_statchg(struct device *);
void	fxp_mdi_write(struct device *, int, int, int);
void	fxp_autosize_eeprom(struct fxp_softc*);
void	fxp_read_eeprom(struct fxp_softc *, u_int16_t *, int, int);
void	fxp_get_info(struct fxp_softc *, u_int8_t *);
void	fxp_tick(void *);
void	fxp_mc_setup(struct fxp_softc *);

void	fxp_shutdown(void *);
void	fxp_power(int, void *);

int	fxp_copy_small = 0;

struct fxp_phytype {
	int	fp_phy;		/* type of PHY, -1 for MII at the end. */
	void	(*fp_init)(struct fxp_softc *);
} fxp_phytype_table[] = {
	{ FXP_PHY_80C24,		fxp_80c24_initmedia },
	{ -1,				fxp_mii_initmedia },
};

/*
 * Set initial transmit threshold at 64 (512 bytes). This is
 * increased by 64 (512 bytes) at a time, to maximum of 192
 * (1536 bytes), if an underrun occurs.
 */
static int tx_threshold = 64;

/*
 * Wait for the previous command to be accepted (but not necessarily
 * completed).
 */
static __inline void
fxp_scb_wait(struct fxp_softc *sc)
{
	int i = 10000;

	while (CSR_READ_1(sc, FXP_CSR_SCB_COMMAND) && --i)
		delay(2);
	if (i == 0)
		printf("%s: WARNING: SCB timed out!\n", sc->sc_dev.dv_xname);
}

/*
 * Submit a command to the i82557.
 */
static __inline void
fxp_scb_cmd(struct fxp_softc *sc, u_int8_t cmd)
{

	if (cmd == FXP_SCB_COMMAND_CU_RESUME &&
	    (sc->sc_flags & FXPF_FIX_RESUME_BUG) != 0) {
		CSR_WRITE_1(sc, FXP_CSR_SCB_COMMAND, FXP_CB_COMMAND_NOP);
		fxp_scb_wait(sc);
	}
	CSR_WRITE_1(sc, FXP_CSR_SCB_COMMAND, cmd);
}

/*
 * Finish attaching an i82557 interface.  Called by bus-specific front-end.
 */
void
fxp_attach(struct fxp_softc *sc)
{
	u_int8_t enaddr[ETHER_ADDR_LEN];
	struct ifnet *ifp;
	bus_dma_segment_t seg;
	int rseg, i, error;
	struct fxp_phytype *fp;

	callout_init(&sc->sc_callout);

	/*
	 * Allocate the control data structures, and create and load the
	 * DMA map for it.
	 */
	if ((error = bus_dmamem_alloc(sc->sc_dmat,
	    sizeof(struct fxp_control_data), PAGE_SIZE, 0, &seg, 1, &rseg,
	    0)) != 0) {
		printf("%s: unable to allocate control data, error = %d\n",
		    sc->sc_dev.dv_xname, error);
		goto fail_0;
	}

	if ((error = bus_dmamem_map(sc->sc_dmat, &seg, rseg,
	    sizeof(struct fxp_control_data), (caddr_t *)&sc->sc_control_data,
	    BUS_DMA_COHERENT)) != 0) {
		printf("%s: unable to map control data, error = %d\n",
		    sc->sc_dev.dv_xname, error);
		goto fail_1;
	}
	sc->sc_cdseg = seg;
	sc->sc_cdnseg = rseg;

	bzero(sc->sc_control_data, sizeof(struct fxp_control_data));

	if ((error = bus_dmamap_create(sc->sc_dmat,
	    sizeof(struct fxp_control_data), 1,
	    sizeof(struct fxp_control_data), 0, 0, &sc->sc_dmamap)) != 0) {
		printf("%s: unable to create control data DMA map, "
		    "error = %d\n", sc->sc_dev.dv_xname, error);
		goto fail_2;
	}

	if ((error = bus_dmamap_load(sc->sc_dmat, sc->sc_dmamap,
	    sc->sc_control_data, sizeof(struct fxp_control_data), NULL,
	    0)) != 0) {
		printf("%s: can't load control data DMA map, error = %d\n",
		    sc->sc_dev.dv_xname, error);
		goto fail_3;
	}

	/*
	 * Create the transmit buffer DMA maps.
	 */
	for (i = 0; i < FXP_NTXCB; i++) {
		if ((error = bus_dmamap_create(sc->sc_dmat, MCLBYTES,
		    FXP_NTXSEG, MCLBYTES, 0, 0,
		    &FXP_DSTX(sc, i)->txs_dmamap)) != 0) {
			printf("%s: unable to create tx DMA map %d, "
			    "error = %d\n", sc->sc_dev.dv_xname, i, error);
			goto fail_4;
		}
	}

	/*
	 * Create the receive buffer DMA maps.
	 */
	for (i = 0; i < FXP_NRFABUFS; i++) {
		if ((error = bus_dmamap_create(sc->sc_dmat, MCLBYTES, 1,
		    MCLBYTES, 0, 0, &sc->sc_rxmaps[i])) != 0) {
			printf("%s: unable to create rx DMA map %d, "
			    "error = %d\n", sc->sc_dev.dv_xname, i, error);
			goto fail_5;
		}
	}

	/* Initialize MAC address and media structures. */
	fxp_get_info(sc, enaddr);

	printf("%s: Ethernet address %s, %s Mb/s\n", sc->sc_dev.dv_xname,
	    ether_sprintf(enaddr), sc->phy_10Mbps_only ? "10" : "10/100");

	ifp = &sc->sc_ethercom.ec_if;

	/*
	 * Get info about our media interface, and initialize it.  Note
	 * the table terminates itself with a phy of -1, indicating
	 * that we're using MII.
	 */
	for (fp = fxp_phytype_table; fp->fp_phy != -1; fp++)
		if (fp->fp_phy == sc->phy_primary_device)
			break;
	(*fp->fp_init)(sc);

	bcopy(sc->sc_dev.dv_xname, ifp->if_xname, IFNAMSIZ);
	ifp->if_softc = sc;
	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
	ifp->if_ioctl = fxp_ioctl;
	ifp->if_start = fxp_start;
	ifp->if_watchdog = fxp_watchdog;
	ifp->if_init = fxp_init;
	ifp->if_stop = fxp_stop;
	IFQ_SET_READY(&ifp->if_snd);

	/*
	 * We can support 802.1Q VLAN-sized frames.
	 */
	sc->sc_ethercom.ec_capabilities |= ETHERCAP_VLAN_MTU;

	/*
	 * Attach the interface.
	 */
	if_attach(ifp);
	ether_ifattach(ifp, enaddr);
#if NRND > 0
	rnd_attach_source(&sc->rnd_source, sc->sc_dev.dv_xname,
	    RND_TYPE_NET, 0);
#endif

	/*
	 * Add shutdown hook so that DMA is disabled prior to reboot. Not
	 * doing do could allow DMA to corrupt kernel memory during the
	 * reboot before the driver initializes.
	 */
	sc->sc_sdhook = shutdownhook_establish(fxp_shutdown, sc);
	if (sc->sc_sdhook == NULL)
		printf("%s: WARNING: unable to establish shutdown hook\n",
		    sc->sc_dev.dv_xname);
	/*
  	 * Add suspend hook, for similar reasons..
	 */
	sc->sc_powerhook = powerhook_establish(fxp_power, sc);
	if (sc->sc_powerhook == NULL)
		printf("%s: WARNING: unable to establish power hook\n",
		    sc->sc_dev.dv_xname);

	/* The attach is successful. */
	sc->sc_flags |= FXPF_ATTACHED;

	return;

	/*
	 * Free any resources we've allocated during the failed attach
	 * attempt.  Do this in reverse order and fall though.
	 */
 fail_5:
	for (i = 0; i < FXP_NRFABUFS; i++) {
		if (sc->sc_rxmaps[i] != NULL)
			bus_dmamap_destroy(sc->sc_dmat, sc->sc_rxmaps[i]);
	}
 fail_4:
	for (i = 0; i < FXP_NTXCB; i++) {
		if (FXP_DSTX(sc, i)->txs_dmamap != NULL)
			bus_dmamap_destroy(sc->sc_dmat,
			    FXP_DSTX(sc, i)->txs_dmamap);
	}
	bus_dmamap_unload(sc->sc_dmat, sc->sc_dmamap);
 fail_3:
	bus_dmamap_destroy(sc->sc_dmat, sc->sc_dmamap);
 fail_2:
	bus_dmamem_unmap(sc->sc_dmat, (caddr_t)sc->sc_control_data,
	    sizeof(struct fxp_control_data));
 fail_1:
	bus_dmamem_free(sc->sc_dmat, &seg, rseg);
 fail_0:
	return;
}

void
fxp_mii_initmedia(struct fxp_softc *sc)
{

	sc->sc_flags |= FXPF_MII;

	sc->sc_mii.mii_ifp = &sc->sc_ethercom.ec_if;
	sc->sc_mii.mii_readreg = fxp_mdi_read;
	sc->sc_mii.mii_writereg = fxp_mdi_write;
	sc->sc_mii.mii_statchg = fxp_statchg;
	ifmedia_init(&sc->sc_mii.mii_media, 0, fxp_mii_mediachange,
	    fxp_mii_mediastatus);
	/*
	 * The i82557 wedges if all of its PHYs are isolated!
	 */
	mii_attach(&sc->sc_dev, &sc->sc_mii, 0xffffffff, MII_PHY_ANY,
	    MII_OFFSET_ANY, MIIF_NOISOLATE);
	if (LIST_FIRST(&sc->sc_mii.mii_phys) == NULL) {
		ifmedia_add(&sc->sc_mii.mii_media, IFM_ETHER|IFM_NONE, 0, NULL);
		ifmedia_set(&sc->sc_mii.mii_media, IFM_ETHER|IFM_NONE);
	} else
		ifmedia_set(&sc->sc_mii.mii_media, IFM_ETHER|IFM_AUTO);
}

void
fxp_80c24_initmedia(struct fxp_softc *sc)
{

	/*
	 * The Seeq 80c24 AutoDUPLEX(tm) Ethernet Interface Adapter
	 * doesn't have a programming interface of any sort.  The
	 * media is sensed automatically based on how the link partner
	 * is configured.  This is, in essence, manual configuration.
	 */
	printf("%s: Seeq 80c24 AutoDUPLEX media interface present\n",
	    sc->sc_dev.dv_xname);
	ifmedia_init(&sc->sc_mii.mii_media, 0, fxp_80c24_mediachange,
	    fxp_80c24_mediastatus);
	ifmedia_add(&sc->sc_mii.mii_media, IFM_ETHER|IFM_MANUAL, 0, NULL);
	ifmedia_set(&sc->sc_mii.mii_media, IFM_ETHER|IFM_MANUAL);
}

/*
 * Device shutdown routine. Called at system shutdown after sync. The
 * main purpose of this routine is to shut off receiver DMA so that
 * kernel memory doesn't get clobbered during warmboot.
 */
void
fxp_shutdown(void *arg)
{
	struct fxp_softc *sc = arg;

	/*
	 * Since the system's going to halt shortly, don't bother
	 * freeing mbufs.
	 */
	fxp_stop(&sc->sc_ethercom.ec_if, 0);
}
/*
 * Power handler routine. Called when the system is transitioning
 * into/out of power save modes.  As with fxp_shutdown, the main
 * purpose of this routine is to shut off receiver DMA so it doesn't
 * clobber kernel memory at the wrong time.
 */
void
fxp_power(int why, void *arg)
{
	struct fxp_softc *sc = arg;
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	int s;

	s = splnet();
	switch (why) {
	case PWR_SUSPEND:
	case PWR_STANDBY:
		fxp_stop(ifp, 0);
		break;
	case PWR_RESUME:
		if (ifp->if_flags & IFF_UP)
			fxp_init(ifp);
		break;
	case PWR_SOFTSUSPEND:
	case PWR_SOFTSTANDBY:
	case PWR_SOFTRESUME:
		break;
	}
	splx(s);
}

/*
 * Initialize the interface media.
 */
void
fxp_get_info(struct fxp_softc *sc, u_int8_t *enaddr)
{
	u_int16_t data, myea[ETHER_ADDR_LEN / 2];

	/*
	 * Reset to a stable state.
	 */
	CSR_WRITE_4(sc, FXP_CSR_PORT, FXP_PORT_SELECTIVE_RESET);
	DELAY(10);

	sc->sc_eeprom_size = 0;
	fxp_autosize_eeprom(sc);
	if(sc->sc_eeprom_size == 0) {
	    printf("%s: failed to detect EEPROM size\n", sc->sc_dev.dv_xname);
	    sc->sc_eeprom_size = 6; /* XXX panic here? */
	}
#ifdef DEBUG
	printf("%s: detected %d word EEPROM\n",
	       sc->sc_dev.dv_xname,
	       1 << sc->sc_eeprom_size);
#endif

	/*
	 * Get info about the primary PHY
	 */
	fxp_read_eeprom(sc, &data, 6, 1);
	sc->phy_primary_addr = data & 0xff;
	sc->phy_primary_device = (data >> 8) & 0x3f;
	sc->phy_10Mbps_only = data >> 15;

	/*
	 * Read MAC address.
	 */
	fxp_read_eeprom(sc, myea, 0, 3);
	enaddr[0] = myea[0] & 0xff;
	enaddr[1] = myea[0] >> 8;
	enaddr[2] = myea[1] & 0xff;
	enaddr[3] = myea[1] >> 8;
	enaddr[4] = myea[2] & 0xff;
	enaddr[5] = myea[2] >> 8;
}

/*
 * Figure out EEPROM size.
 *
 * 559's can have either 64-word or 256-word EEPROMs, the 558
 * datasheet only talks about 64-word EEPROMs, and the 557 datasheet
 * talks about the existance of 16 to 256 word EEPROMs.
 *
 * The only known sizes are 64 and 256, where the 256 version is used
 * by CardBus cards to store CIS information.
 *
 * The address is shifted in msb-to-lsb, and after the last
 * address-bit the EEPROM is supposed to output a `dummy zero' bit,
 * after which follows the actual data. We try to detect this zero, by
 * probing the data-out bit in the EEPROM control register just after
 * having shifted in a bit. If the bit is zero, we assume we've
 * shifted enough address bits. The data-out should be tri-state,
 * before this, which should translate to a logical one.
 *
 * Other ways to do this would be to try to read a register with known
 * contents with a varying number of address bits, but no such
 * register seem to be available. The high bits of register 10 are 01
 * on the 558 and 559, but apparently not on the 557.
 *
 * The Linux driver computes a checksum on the EEPROM data, but the
 * value of this checksum is not very well documented.
 */

void
fxp_autosize_eeprom(struct fxp_softc *sc)
{
	u_int16_t reg;
	int x;

	CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, FXP_EEPROM_EECS);
	/*
	 * Shift in read opcode.
	 */
	for (x = 3; x > 0; x--) {
		if (FXP_EEPROM_OPC_READ & (1 << (x - 1))) {
			reg = FXP_EEPROM_EECS | FXP_EEPROM_EEDI;
		} else {
			reg = FXP_EEPROM_EECS;
		}
		CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
		CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL,
			    reg | FXP_EEPROM_EESK);
		DELAY(4);
		CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
		DELAY(4);
	}
	/*
	 * Shift in address, wait for the dummy zero following a correct
	 * address shift.
	 */
	for (x = 1; x <=  8; x++) {
		CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, FXP_EEPROM_EECS);
		CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL,
		    FXP_EEPROM_EECS | FXP_EEPROM_EESK);
		DELAY(4);
		if((CSR_READ_2(sc, FXP_CSR_EEPROMCONTROL) &
		    FXP_EEPROM_EEDO) == 0)
			break;
		CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, FXP_EEPROM_EECS);
		DELAY(4);
	}
	CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, 0);
	DELAY(4);
	if(x != 6 && x != 8) {
#ifdef DEBUG
		printf("%s: strange EEPROM size (%d)\n",
		       sc->sc_dev.dv_xname, 1 << x);
#endif
	} else
		sc->sc_eeprom_size = x;
}

/*
 * Read from the serial EEPROM. Basically, you manually shift in
 * the read opcode (one bit at a time) and then shift in the address,
 * and then you shift out the data (all of this one bit at a time).
 * The word size is 16 bits, so you have to provide the address for
 * every 16 bits of data.
 */
void
fxp_read_eeprom(struct fxp_softc *sc, u_int16_t *data, int offset, int words)
{
	u_int16_t reg;
	int i, x;

	for (i = 0; i < words; i++) {
		CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, FXP_EEPROM_EECS);
		/*
		 * Shift in read opcode.
		 */
		for (x = 3; x > 0; x--) {
			if (FXP_EEPROM_OPC_READ & (1 << (x - 1))) {
				reg = FXP_EEPROM_EECS | FXP_EEPROM_EEDI;
			} else {
				reg = FXP_EEPROM_EECS;
			}
			CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
			CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL,
			    reg | FXP_EEPROM_EESK);
			DELAY(4);
			CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
			DELAY(4);
		}
		/*
		 * Shift in address.
		 */
		for (x = sc->sc_eeprom_size; x > 0; x--) {
			if ((i + offset) & (1 << (x - 1))) {
			    reg = FXP_EEPROM_EECS | FXP_EEPROM_EEDI;
			} else {
			    reg = FXP_EEPROM_EECS;
			}
			CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
			CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL,
			    reg | FXP_EEPROM_EESK);
			DELAY(4);
			CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
			DELAY(4);
		}
		reg = FXP_EEPROM_EECS;
		data[i] = 0;
		/*
		 * Shift out data.
		 */
		for (x = 16; x > 0; x--) {
			CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL,
			    reg | FXP_EEPROM_EESK);
			DELAY(4);
			if (CSR_READ_2(sc, FXP_CSR_EEPROMCONTROL) &
			    FXP_EEPROM_EEDO)
				data[i] |= (1 << (x - 1));
			CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, reg);
			DELAY(4);
		}
		CSR_WRITE_2(sc, FXP_CSR_EEPROMCONTROL, 0);
		DELAY(4);
	}
}

/*
 * Start packet transmission on the interface.
 */
void
fxp_start(struct ifnet *ifp)
{
	struct fxp_softc *sc = ifp->if_softc;
	struct mbuf *m0, *m;
	struct fxp_cb_tx *txd;
	struct fxp_txsoft *txs;
	struct fxp_tbdlist *tbd;
	bus_dmamap_t dmamap;
	int error, lasttx, nexttx, opending, seg;

	/*
	 * If we want a re-init, bail out now.
	 */
	if (sc->sc_flags & FXPF_WANTINIT) {
		ifp->if_flags |= IFF_OACTIVE;
		return;
	}

	if ((ifp->if_flags & (IFF_RUNNING|IFF_OACTIVE)) != IFF_RUNNING)
		return;

	/*
	 * Remember the previous txpending and the current lasttx.
	 */
	opending = sc->sc_txpending;
	lasttx = sc->sc_txlast;

	/*
	 * Loop through the send queue, setting up transmit descriptors
	 * until we drain the queue, or use up all available transmit
	 * descriptors.
	 */
	while (sc->sc_txpending < FXP_NTXCB) {
		/*
		 * Grab a packet off the queue.
		 */
		IFQ_POLL(&ifp->if_snd, m0);
		if (m0 == NULL)
			break;
		m = NULL;

		/*
		 * Get the next available transmit descriptor.
		 */
		nexttx = FXP_NEXTTX(sc->sc_txlast);
		txd = FXP_CDTX(sc, nexttx);
		tbd = FXP_CDTBD(sc, nexttx);
		txs = FXP_DSTX(sc, nexttx);
		dmamap = txs->txs_dmamap;

		/*
		 * Load the DMA map.  If this fails, the packet either
		 * didn't fit in the allotted number of frags, or we were
		 * short on resources.  In this case, we'll copy and try
		 * again.
		 */
		if (bus_dmamap_load_mbuf(sc->sc_dmat, dmamap, m0,
		    BUS_DMA_NOWAIT) != 0) {
			MGETHDR(m, M_DONTWAIT, MT_DATA);
			if (m == NULL) {
				printf("%s: unable to allocate Tx mbuf\n",
				    sc->sc_dev.dv_xname);
				break;
			}
			if (m0->m_pkthdr.len > MHLEN) {
				MCLGET(m, M_DONTWAIT);
				if ((m->m_flags & M_EXT) == 0) {
					printf("%s: unable to allocate Tx "
					    "cluster\n", sc->sc_dev.dv_xname);
					m_freem(m);
					break;
				}
			}
			m_copydata(m0, 0, m0->m_pkthdr.len, mtod(m, caddr_t));
			m->m_pkthdr.len = m->m_len = m0->m_pkthdr.len;
			error = bus_dmamap_load_mbuf(sc->sc_dmat, dmamap,
			    m, BUS_DMA_NOWAIT);
			if (error) {
				printf("%s: unable to load Tx buffer, "
				    "error = %d\n", sc->sc_dev.dv_xname, error);
				break;
			}
		}

		IFQ_DEQUEUE(&ifp->if_snd, m0);
		if (m != NULL) {
			m_freem(m0);
			m0 = m;
		}

		/* Initialize the fraglist. */
		for (seg = 0; seg < dmamap->dm_nsegs; seg++) {
			tbd->tbd_d[seg].tb_addr =
			    htole32(dmamap->dm_segs[seg].ds_addr);
			tbd->tbd_d[seg].tb_size =
			    htole32(dmamap->dm_segs[seg].ds_len);
		}

		FXP_CDTBDSYNC(sc, nexttx, BUS_DMASYNC_PREWRITE);

		/* Sync the DMA map. */
		bus_dmamap_sync(sc->sc_dmat, dmamap, 0, dmamap->dm_mapsize,
		    BUS_DMASYNC_PREWRITE);

		/*
		 * Store a pointer to the packet so we can free it later.
		 */
		txs->txs_mbuf = m0;

		/*
		 * Initialize the transmit descriptor.
		 */
		/* BIG_ENDIAN: no need to swap to store 0 */
		txd->cb_status = 0;
		txd->cb_command =
		    htole16(FXP_CB_COMMAND_XMIT | FXP_CB_COMMAND_SF);
		txd->tx_threshold = tx_threshold;
		txd->tbd_number = dmamap->dm_nsegs;

		FXP_CDTXSYNC(sc, nexttx,
		    BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);

		/* Advance the tx pointer. */
		sc->sc_txpending++;
		sc->sc_txlast = nexttx;

#if NBPFILTER > 0
		/*
		 * Pass packet to bpf if there is a listener.
		 */
		if (ifp->if_bpf)
			bpf_mtap(ifp->if_bpf, m0);
#endif
	}

	if (sc->sc_txpending == FXP_NTXCB) {
		/* No more slots; notify upper layer. */
		ifp->if_flags |= IFF_OACTIVE;
	}

	if (sc->sc_txpending != opending) {
		/*
		 * We enqueued packets.  If the transmitter was idle,
		 * reset the txdirty pointer.
		 */
		if (opending == 0)
			sc->sc_txdirty = FXP_NEXTTX(lasttx);

		/*
		 * Cause the chip to interrupt and suspend command
		 * processing once the last packet we've enqueued
		 * has been transmitted.
		 */
		FXP_CDTX(sc, sc->sc_txlast)->cb_command |=
		    htole16(FXP_CB_COMMAND_I | FXP_CB_COMMAND_S);
		FXP_CDTXSYNC(sc, sc->sc_txlast,
		    BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);

		/*
		 * The entire packet chain is set up.  Clear the suspend bit
		 * on the command prior to the first packet we set up.
		 */
		FXP_CDTXSYNC(sc, lasttx,
		    BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);
		FXP_CDTX(sc, lasttx)->cb_command &= htole16(~FXP_CB_COMMAND_S);
		FXP_CDTXSYNC(sc, lasttx,
		    BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);

		/*
		 * Issue a Resume command in case the chip was suspended.
		 */
		fxp_scb_wait(sc);
		fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_RESUME);

		/* Set a watchdog timer in case the chip flakes out. */
		ifp->if_timer = 5;
	}
}

/*
 * Process interface interrupts.
 */
int
fxp_intr(void *arg)
{
	struct fxp_softc *sc = arg;
	struct ethercom *ec = &sc->sc_ethercom;
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	struct fxp_cb_tx *txd;
	struct fxp_txsoft *txs;
	struct mbuf *m, *m0;
	bus_dmamap_t rxmap;
	struct fxp_rfa *rfa;
	int i, claimed = 0;
	u_int16_t len, rxstat, txstat;
	u_int8_t statack;

	if ((sc->sc_dev.dv_flags & DVF_ACTIVE) == 0)
		return (0);
	/*
	 * If the interface isn't running, don't try to
	 * service the interrupt.. just ack it and bail.
	 */
	if ((ifp->if_flags & IFF_RUNNING) == 0) {
		statack = CSR_READ_1(sc, FXP_CSR_SCB_STATACK);
		if (statack) {
			claimed = 1;
			CSR_WRITE_1(sc, FXP_CSR_SCB_STATACK, statack);
		}
		return (claimed);
	}

	while ((statack = CSR_READ_1(sc, FXP_CSR_SCB_STATACK)) != 0) {
		claimed = 1;

		/*
		 * First ACK all the interrupts in this pass.
		 */
		CSR_WRITE_1(sc, FXP_CSR_SCB_STATACK, statack);

		/*
		 * Process receiver interrupts. If a no-resource (RNR)
		 * condition exists, get whatever packets we can and
		 * re-start the receiver.
		 */
		if (statack & (FXP_SCB_STATACK_FR | FXP_SCB_STATACK_RNR)) {
 rcvloop:
			m = sc->sc_rxq.ifq_head;
			rfa = FXP_MTORFA(m);
			rxmap = M_GETCTX(m, bus_dmamap_t);

			FXP_RFASYNC(sc, m,
			    BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);

			rxstat = le16toh(rfa->rfa_status);

			if ((rxstat & FXP_RFA_STATUS_C) == 0) {
				/*
				 * We have processed all of the
				 * receive buffers.
				 */
				FXP_RFASYNC(sc, m, BUS_DMASYNC_PREREAD);
				goto do_transmit;
			}

			IF_DEQUEUE(&sc->sc_rxq, m);

			FXP_RXBUFSYNC(sc, m, BUS_DMASYNC_POSTREAD);

			len = le16toh(rfa->actual_size) &
			    (m->m_ext.ext_size - 1);

			if (len < sizeof(struct ether_header)) {
				/*
				 * Runt packet; drop it now.
				 */
				FXP_INIT_RFABUF(sc, m);
				goto rcvloop;
			}

			/*
			 * If support for 802.1Q VLAN sized frames is
			 * enabled, we need to do some additional error
			 * checking (as we are saving bad frames, in
			 * order to receive the larger ones).
			 */
			if ((ec->ec_capenable & ETHERCAP_VLAN_MTU) != 0 &&
			    (rxstat & (FXP_RFA_STATUS_OVERRUN|
				       FXP_RFA_STATUS_RNR|
				       FXP_RFA_STATUS_ALIGN|
				       FXP_RFA_STATUS_CRC)) != 0) {
				FXP_INIT_RFABUF(sc, m);
				goto rcvloop;
			}

			/*
			 * If the packet is small enough to fit in a
			 * single header mbuf, allocate one and copy
			 * the data into it.  This greatly reduces
			 * memory consumption when we receive lots
			 * of small packets.
			 *
			 * Otherwise, we add a new buffer to the receive
			 * chain.  If this fails, we drop the packet and
			 * recycle the old buffer.
			 */
			if (fxp_copy_small != 0 && len <= MHLEN) {
				MGETHDR(m0, M_DONTWAIT, MT_DATA);
				if (m == NULL)
					goto dropit;
				memcpy(mtod(m0, caddr_t),
				    mtod(m, caddr_t), len);
				FXP_INIT_RFABUF(sc, m);
				m = m0;
			} else {
				if (fxp_add_rfabuf(sc, rxmap, 1) != 0) {
 dropit:
					ifp->if_ierrors++;
					FXP_INIT_RFABUF(sc, m);
					goto rcvloop;
				}
			}

			m->m_pkthdr.rcvif = ifp;
			m->m_pkthdr.len = m->m_len = len;

#if NBPFILTER > 0
			/*
			 * Pass this up to any BPF listeners, but only
			 * pass it up the stack it its for us.
			 */
			if (ifp->if_bpf)
				bpf_mtap(ifp->if_bpf, m);
#endif

			/* Pass it on. */
			(*ifp->if_input)(ifp, m);
			goto rcvloop;
		}

 do_transmit:
		if (statack & FXP_SCB_STATACK_RNR) {
			rxmap = M_GETCTX(sc->sc_rxq.ifq_head, bus_dmamap_t);
			fxp_scb_wait(sc);
			CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL,
			    rxmap->dm_segs[0].ds_addr +
			    RFA_ALIGNMENT_FUDGE);
			fxp_scb_cmd(sc, FXP_SCB_COMMAND_RU_START);
		}

		/*
		 * Free any finished transmit mbuf chains.
		 */
		if (statack & (FXP_SCB_STATACK_CXTNO|FXP_SCB_STATACK_CNA)) {
			ifp->if_flags &= ~IFF_OACTIVE;
			for (i = sc->sc_txdirty; sc->sc_txpending != 0;
			     i = FXP_NEXTTX(i), sc->sc_txpending--) {
				txd = FXP_CDTX(sc, i);
				txs = FXP_DSTX(sc, i);

				FXP_CDTXSYNC(sc, i,
				    BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);

				txstat = le16toh(txd->cb_status);

				if ((txstat & FXP_CB_STATUS_C) == 0)
					break;

				FXP_CDTBDSYNC(sc, i, BUS_DMASYNC_POSTWRITE);

				bus_dmamap_sync(sc->sc_dmat, txs->txs_dmamap,
				    0, txs->txs_dmamap->dm_mapsize,
				    BUS_DMASYNC_POSTWRITE);
				bus_dmamap_unload(sc->sc_dmat, txs->txs_dmamap);
				m_freem(txs->txs_mbuf);
				txs->txs_mbuf = NULL;
			}

			/* Update the dirty transmit buffer pointer. */
			sc->sc_txdirty = i;

			/*
			 * Cancel the watchdog timer if there are no pending
			 * transmissions.
			 */
			if (sc->sc_txpending == 0) {
				ifp->if_timer = 0;

				/*
				 * If we want a re-init, do that now.
				 */
				if (sc->sc_flags & FXPF_WANTINIT)
					(void) fxp_init(ifp);
			}

			/*
			 * Try to get more packets going.
			 */
			fxp_start(ifp);
		}
	}

#if NRND > 0
	if (claimed)
		rnd_add_uint32(&sc->rnd_source, statack);
#endif
	return (claimed);
}

/*
 * Update packet in/out/collision statistics. The i82557 doesn't
 * allow you to access these counters without doing a fairly
 * expensive DMA to get _all_ of the statistics it maintains, so
 * we do this operation here only once per second. The statistics
 * counters in the kernel are updated from the previous dump-stats
 * DMA and then a new dump-stats DMA is started. The on-chip
 * counters are zeroed when the DMA completes. If we can't start
 * the DMA immediately, we don't wait - we just prepare to read
 * them again next time.
 */
void
fxp_tick(void *arg)
{
	struct fxp_softc *sc = arg;
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	struct fxp_stats *sp = &sc->sc_control_data->fcd_stats;
	int s;

	if ((sc->sc_dev.dv_flags & DVF_ACTIVE) == 0)
		return;

	s = splnet();

	FXP_CDSTATSSYNC(sc, BUS_DMASYNC_POSTREAD);

	ifp->if_opackets += le32toh(sp->tx_good);
	ifp->if_collisions += le32toh(sp->tx_total_collisions);
	if (sp->rx_good) {
		ifp->if_ipackets += le32toh(sp->rx_good);
		sc->sc_rxidle = 0;
	} else {
		sc->sc_rxidle++;
	}
	ifp->if_ierrors +=
	    le32toh(sp->rx_crc_errors) +
	    le32toh(sp->rx_alignment_errors) +
	    le32toh(sp->rx_rnr_errors) +
	    le32toh(sp->rx_overrun_errors);
	/*
	 * If any transmit underruns occured, bump up the transmit
	 * threshold by another 512 bytes (64 * 8).
	 */
	if (sp->tx_underruns) {
		ifp->if_oerrors += le32toh(sp->tx_underruns);
		if (tx_threshold < 192)
			tx_threshold += 64;
	}

	/*
	 * If we haven't received any packets in FXP_MAC_RX_IDLE seconds,
	 * then assume the receiver has locked up and attempt to clear
	 * the condition by reprogramming the multicast filter (actually,
	 * resetting the interface). This is a work-around for a bug in
	 * the 82557 where the receiver locks up if it gets certain types
	 * of garbage in the syncronization bits prior to the packet header.
	 * This bug is supposed to only occur in 10Mbps mode, but has been
	 * seen to occur in 100Mbps mode as well (perhaps due to a 10/100
	 * speed transition).
	 */
	if (sc->sc_rxidle > FXP_MAX_RX_IDLE) {
		(void) fxp_init(ifp);
		splx(s);
		return;
	}
	/*
	 * If there is no pending command, start another stats
	 * dump. Otherwise punt for now.
	 */
	if (CSR_READ_1(sc, FXP_CSR_SCB_COMMAND) == 0) {
		/*
		 * Start another stats dump.
		 */
		FXP_CDSTATSSYNC(sc, BUS_DMASYNC_PREREAD);
		fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_DUMPRESET);
	} else {
		/*
		 * A previous command is still waiting to be accepted.
		 * Just zero our copy of the stats and wait for the
		 * next timer event to update them.
		 */
		/* BIG_ENDIAN: no swap required to store 0 */
		sp->tx_good = 0;
		sp->tx_underruns = 0;
		sp->tx_total_collisions = 0;

		sp->rx_good = 0;
		sp->rx_crc_errors = 0;
		sp->rx_alignment_errors = 0;
		sp->rx_rnr_errors = 0;
		sp->rx_overrun_errors = 0;
	}

	if (sc->sc_flags & FXPF_MII) {
		/* Tick the MII clock. */
		mii_tick(&sc->sc_mii);
	}

	splx(s);

	/*
	 * Schedule another timeout one second from now.
	 */
	callout_reset(&sc->sc_callout, hz, fxp_tick, sc);
}

/*
 * Drain the receive queue.
 */
void
fxp_rxdrain(struct fxp_softc *sc)
{
	bus_dmamap_t rxmap;
	struct mbuf *m;

	for (;;) {
		IF_DEQUEUE(&sc->sc_rxq, m);
		if (m == NULL)
			break;
		rxmap = M_GETCTX(m, bus_dmamap_t);
		bus_dmamap_unload(sc->sc_dmat, rxmap);
		FXP_RXMAP_PUT(sc, rxmap);
		m_freem(m);
	}
}

/*
 * Stop the interface. Cancels the statistics updater and resets
 * the interface.
 */
void
fxp_stop(struct ifnet *ifp, int disable)
{
	struct fxp_softc *sc = ifp->if_softc;
	struct fxp_txsoft *txs;
	int i;

	/*
	 * Turn down interface (done early to avoid bad interactions
	 * between panics, shutdown hooks, and the watchdog timer)
	 */
	ifp->if_timer = 0;
	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);

	/*
	 * Cancel stats updater.
	 */
	callout_stop(&sc->sc_callout);
	if (sc->sc_flags & FXPF_MII) {
		/* Down the MII. */
		mii_down(&sc->sc_mii);
	}

	/*
	 * Issue software reset
	 */
	CSR_WRITE_4(sc, FXP_CSR_PORT, FXP_PORT_SELECTIVE_RESET);
	DELAY(10);

	/*
	 * Release any xmit buffers.
	 */
	for (i = 0; i < FXP_NTXCB; i++) {
		txs = FXP_DSTX(sc, i);
		if (txs->txs_mbuf != NULL) {
			bus_dmamap_unload(sc->sc_dmat, txs->txs_dmamap);
			m_freem(txs->txs_mbuf);
			txs->txs_mbuf = NULL;
		}
	}
	sc->sc_txpending = 0;

	if (disable) {
		fxp_rxdrain(sc);
		fxp_disable(sc);
	}

}

/*
 * Watchdog/transmission transmit timeout handler. Called when a
 * transmission is started on the interface, but no interrupt is
 * received before the timeout. This usually indicates that the
 * card has wedged for some reason.
 */
void
fxp_watchdog(struct ifnet *ifp)
{
	struct fxp_softc *sc = ifp->if_softc;

	printf("%s: device timeout\n", sc->sc_dev.dv_xname);
	ifp->if_oerrors++;

	(void) fxp_init(ifp);
}

/*
 * Initialize the interface.  Must be called at splnet().
 */
int
fxp_init(struct ifnet *ifp)
{
	struct fxp_softc *sc = ifp->if_softc;
	struct fxp_cb_config *cbp;
	struct fxp_cb_ias *cb_ias;
	struct fxp_cb_tx *txd;
	bus_dmamap_t rxmap;
	int i, prm, save_bf, allm, error = 0;

	if ((error = fxp_enable(sc)) != 0)
		goto out;

	/*
	 * Cancel any pending I/O
	 */
	fxp_stop(ifp, 0);

	/*
	 * XXX just setting sc_flags to 0 here clears any FXPF_MII
	 * flag, and this prevents the MII from detaching resulting in
	 * a panic. The flags field should perhaps be split in runtime
	 * flags and more static information. For now, just clear the
	 * only other flag set.
	 */

	sc->sc_flags &= ~FXPF_WANTINIT;

	/*
	 * Initialize base of CBL and RFA memory. Loading with zero
	 * sets it up for regular linear addressing.
	 */
	fxp_scb_wait(sc);
	CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, 0);
	fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_BASE);

	fxp_scb_wait(sc);
	fxp_scb_cmd(sc, FXP_SCB_COMMAND_RU_BASE);

	/*
	 * Initialize the multicast filter.  Do this now, since we might
	 * have to setup the config block differently.
	 */
	fxp_mc_setup(sc);

	prm = (ifp->if_flags & IFF_PROMISC) ? 1 : 0;
	allm = (ifp->if_flags & IFF_ALLMULTI) ? 1 : 0;

	/*
	 * In order to support receiving 802.1Q VLAN frames, we have to
	 * enable "save bad frames", since they are 4 bytes larger than
	 * the normal Ethernet maximum frame length.
	 */
	save_bf = (sc->sc_ethercom.ec_capenable & ETHERCAP_VLAN_MTU) ? 1 : 0;

	/*
	 * Initialize base of dump-stats buffer.
	 */
	fxp_scb_wait(sc);
	CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL,
	    sc->sc_cddma + FXP_CDSTATSOFF);
	FXP_CDSTATSSYNC(sc, BUS_DMASYNC_PREREAD);
	fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_DUMP_ADR);

	cbp = &sc->sc_control_data->fcd_configcb;
	memset(cbp, 0, sizeof(struct fxp_cb_config));

	/*
	 * This copy is kind of disgusting, but there are a bunch of must be
	 * zero and must be one bits in this structure and this is the easiest
	 * way to initialize them all to proper values.
	 */
	memcpy(cbp, fxp_cb_config_template, sizeof(fxp_cb_config_template));

	/* BIG_ENDIAN: no need to swap to store 0 */
	cbp->cb_status =	0;
	cbp->cb_command =	htole16(FXP_CB_COMMAND_CONFIG |
				    FXP_CB_COMMAND_EL);
	/* BIG_ENDIAN: no need to swap to store 0xffffffff */
	cbp->link_addr =	0xffffffff; /* (no) next command */
	cbp->byte_count =	22;	/* (22) bytes to config */
	cbp->rx_fifo_limit =	8;	/* rx fifo threshold (32 bytes) */
	cbp->tx_fifo_limit =	0;	/* tx fifo threshold (0 bytes) */
	cbp->adaptive_ifs =	0;	/* (no) adaptive interframe spacing */
	cbp->rx_dma_bytecount =	0;	/* (no) rx DMA max */
	cbp->tx_dma_bytecount =	0;	/* (no) tx DMA max */
	cbp->dma_bce =		0;	/* (disable) dma max counters */
	cbp->late_scb =		0;	/* (don't) defer SCB update */
	cbp->tno_int =		0;	/* (disable) tx not okay interrupt */
	cbp->ci_int =		1;	/* interrupt on CU idle */
	cbp->save_bf =		save_bf;/* save bad frames */
	cbp->disc_short_rx =	!prm;	/* discard short packets */
	cbp->underrun_retry =	1;	/* retry mode (1) on DMA underrun */
	cbp->mediatype =	!sc->phy_10Mbps_only; /* interface mode */
	cbp->nsai =		1;	/* (don't) disable source addr insert */
	cbp->preamble_length =	2;	/* (7 byte) preamble */
	cbp->loopback =		0;	/* (don't) loopback */
	cbp->linear_priority =	0;	/* (normal CSMA/CD operation) */
	cbp->linear_pri_mode =	0;	/* (wait after xmit only) */
	cbp->interfrm_spacing =	6;	/* (96 bits of) interframe spacing */
	cbp->promiscuous =	prm;	/* promiscuous mode */
	cbp->bcast_disable =	0;	/* (don't) disable broadcasts */
	cbp->crscdt =		0;	/* (CRS only) */
	cbp->stripping =	!prm;	/* truncate rx packet to byte count */
	cbp->padding =		1;	/* (do) pad short tx packets */
	cbp->rcv_crc_xfer =	0;	/* (don't) xfer CRC to host */
	cbp->force_fdx =	0;	/* (don't) force full duplex */
	cbp->fdx_pin_en =	1;	/* (enable) FDX# pin */
	cbp->multi_ia =		0;	/* (don't) accept multiple IAs */
	cbp->mc_all =		allm;	/* accept all multicasts */

	FXP_CDCONFIGSYNC(sc, BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);

	/*
	 * Start the config command/DMA.
	 */
	fxp_scb_wait(sc);
	CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, sc->sc_cddma + FXP_CDCONFIGOFF);
	fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_START);
	/* ...and wait for it to complete. */
	i = 1000;
	do {
		FXP_CDCONFIGSYNC(sc,
		    BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);
		DELAY(1);
	} while ((le16toh(cbp->cb_status) & FXP_CB_STATUS_C) == 0 && --i);
	if (i == 0) {
		printf("%s at line %d: dmasync timeout\n",
		    sc->sc_dev.dv_xname, __LINE__);
		return ETIMEDOUT;
	}

	/*
	 * Initialize the station address.
	 */
	cb_ias = &sc->sc_control_data->fcd_iascb;
	/* BIG_ENDIAN: no need to swap to store 0 */
	cb_ias->cb_status = 0;
	cb_ias->cb_command = htole16(FXP_CB_COMMAND_IAS | FXP_CB_COMMAND_EL);
	/* BIG_ENDIAN: no need to swap to store 0xffffffff */
	cb_ias->link_addr = 0xffffffff;
	memcpy((void *)cb_ias->macaddr, LLADDR(ifp->if_sadl), ETHER_ADDR_LEN);

	FXP_CDIASSYNC(sc, BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);

	/*
	 * Start the IAS (Individual Address Setup) command/DMA.
	 */
	fxp_scb_wait(sc);
	CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, sc->sc_cddma + FXP_CDIASOFF);
	fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_START);
	/* ...and wait for it to complete. */
	i = 1000;
	do {
		FXP_CDIASSYNC(sc,
		    BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);
		DELAY(1);
	} while ((le16toh(cb_ias->cb_status) & FXP_CB_STATUS_C) == 0 && --i);
	if (i == 0) {
		printf("%s at line %d: dmasync timeout\n",
		    sc->sc_dev.dv_xname, __LINE__);
		return ETIMEDOUT;
	}

	/*
	 * Initialize the transmit descriptor ring.  txlast is initialized
	 * to the end of the list so that it will wrap around to the first
	 * descriptor when the first packet is transmitted.
	 */
	for (i = 0; i < FXP_NTXCB; i++) {
		txd = FXP_CDTX(sc, i);
		memset(txd, 0, sizeof(struct fxp_cb_tx));
		txd->cb_command =
		    htole16(FXP_CB_COMMAND_NOP | FXP_CB_COMMAND_S);
		txd->tbd_array_addr = htole32(FXP_CDTBDADDR(sc, i));
		txd->link_addr = htole32(FXP_CDTXADDR(sc, FXP_NEXTTX(i)));
		FXP_CDTXSYNC(sc, i, BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);
	}
	sc->sc_txpending = 0;
	sc->sc_txdirty = 0;
	sc->sc_txlast = FXP_NTXCB - 1;

	/*
	 * Initialize the receive buffer list.
	 */
	sc->sc_rxq.ifq_maxlen = FXP_NRFABUFS;
	while (sc->sc_rxq.ifq_len < FXP_NRFABUFS) {
		rxmap = FXP_RXMAP_GET(sc);
		if ((error = fxp_add_rfabuf(sc, rxmap, 0)) != 0) {
			printf("%s: unable to allocate or map rx "
			    "buffer %d, error = %d\n",
			    sc->sc_dev.dv_xname,
			    sc->sc_rxq.ifq_len, error);
			/*
			 * XXX Should attempt to run with fewer receive
			 * XXX buffers instead of just failing.
			 */
			FXP_RXMAP_PUT(sc, rxmap);
			fxp_rxdrain(sc);
			goto out;
		}
	}
	sc->sc_rxidle = 0;

	/*
	 * Give the transmit ring to the chip.  We do this by pointing
	 * the chip at the last descriptor (which is a NOP|SUSPEND), and
	 * issuing a start command.  It will execute the NOP and then
	 * suspend, pointing at the first descriptor.
	 */
	fxp_scb_wait(sc);
	CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, FXP_CDTXADDR(sc, sc->sc_txlast));
	fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_START);

	/*
	 * Initialize receiver buffer area - RFA.
	 */
	rxmap = M_GETCTX(sc->sc_rxq.ifq_head, bus_dmamap_t);
	fxp_scb_wait(sc);
	CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL,
	    rxmap->dm_segs[0].ds_addr + RFA_ALIGNMENT_FUDGE);
	fxp_scb_cmd(sc, FXP_SCB_COMMAND_RU_START);

	if (sc->sc_flags & FXPF_MII) {
		/*
		 * Set current media.
		 */
		mii_mediachg(&sc->sc_mii);
	}

	/*
	 * ...all done!
	 */
	ifp->if_flags |= IFF_RUNNING;
	ifp->if_flags &= ~IFF_OACTIVE;

	/*
	 * Start the one second timer.
	 */
	callout_reset(&sc->sc_callout, hz, fxp_tick, sc);

	/*
	 * Attempt to start output on the interface.
	 */
	fxp_start(ifp);

 out:
	if (error) {
		ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
		ifp->if_timer = 0;
		printf("%s: interface not running\n", sc->sc_dev.dv_xname);
	}
	return (error);
}

/*
 * Change media according to request.
 */
int
fxp_mii_mediachange(struct ifnet *ifp)
{
	struct fxp_softc *sc = ifp->if_softc;

	if (ifp->if_flags & IFF_UP)
		mii_mediachg(&sc->sc_mii);
	return (0);
}

/*
 * Notify the world which media we're using.
 */
void
fxp_mii_mediastatus(struct ifnet *ifp, struct ifmediareq *ifmr)
{
	struct fxp_softc *sc = ifp->if_softc;

	if(sc->sc_enabled == 0) {
		ifmr->ifm_active = IFM_ETHER | IFM_NONE;
		ifmr->ifm_status = 0;
		return;
	}

	mii_pollstat(&sc->sc_mii);
	ifmr->ifm_status = sc->sc_mii.mii_media_status;
	ifmr->ifm_active = sc->sc_mii.mii_media_active;
}

int
fxp_80c24_mediachange(struct ifnet *ifp)
{

	/* Nothing to do here. */
	return (0);
}

void
fxp_80c24_mediastatus(struct ifnet *ifp, struct ifmediareq *ifmr)
{
	struct fxp_softc *sc = ifp->if_softc;

	/*
	 * Media is currently-selected media.  We cannot determine
	 * the link status.
	 */
	ifmr->ifm_status = 0;
	ifmr->ifm_active = sc->sc_mii.mii_media.ifm_cur->ifm_media;
}

/*
 * Add a buffer to the end of the RFA buffer list.
 * Return 0 if successful, error code on failure.
 *
 * The RFA struct is stuck at the beginning of mbuf cluster and the
 * data pointer is fixed up to point just past it.
 */
int
fxp_add_rfabuf(struct fxp_softc *sc, bus_dmamap_t rxmap, int unload)
{
	struct mbuf *m;
	int error;

	MGETHDR(m, M_DONTWAIT, MT_DATA);
	if (m == NULL)
		return (ENOBUFS);

	MCLGET(m, M_DONTWAIT);
	if ((m->m_flags & M_EXT) == 0) {
		m_freem(m);
		return (ENOBUFS);
	}

	if (unload)
		bus_dmamap_unload(sc->sc_dmat, rxmap);

	M_SETCTX(m, rxmap);

	error = bus_dmamap_load(sc->sc_dmat, rxmap,
	    m->m_ext.ext_buf, m->m_ext.ext_size, NULL, BUS_DMA_NOWAIT);
	if (error) {
		printf("%s: can't load rx DMA map %d, error = %d\n",
		    sc->sc_dev.dv_xname, sc->sc_rxq.ifq_len, error);
		panic("fxp_add_rfabuf");		/* XXX */
	}

	FXP_INIT_RFABUF(sc, m);

	return (0);
}

int
fxp_mdi_read(struct device *self, int phy, int reg)
{
	struct fxp_softc *sc = (struct fxp_softc *)self;
	int count = 10000;
	int value;

	CSR_WRITE_4(sc, FXP_CSR_MDICONTROL,
	    (FXP_MDI_READ << 26) | (reg << 16) | (phy << 21));

	while (((value = CSR_READ_4(sc, FXP_CSR_MDICONTROL)) & 0x10000000) == 0
	    && count--)
		DELAY(10);

	if (count <= 0)
		printf("%s: fxp_mdi_read: timed out\n", sc->sc_dev.dv_xname);

	return (value & 0xffff);
}

void
fxp_statchg(struct device *self)
{
	struct fxp_softc *sc = (void *) self;

	/*
	 * Determine whether or not we have to work-around the
	 * Resume Bug.
	 */
	if (sc->sc_flags & FXPF_HAS_RESUME_BUG) {
		if (IFM_TYPE(sc->sc_mii.mii_media_active) == IFM_10_T)
			sc->sc_flags |= FXPF_FIX_RESUME_BUG;
		else
			sc->sc_flags &= ~FXPF_FIX_RESUME_BUG;
	}
}

void
fxp_mdi_write(struct device *self, int phy, int reg, int value)
{
	struct fxp_softc *sc = (struct fxp_softc *)self;
	int count = 10000;

	CSR_WRITE_4(sc, FXP_CSR_MDICONTROL,
	    (FXP_MDI_WRITE << 26) | (reg << 16) | (phy << 21) |
	    (value & 0xffff));

	while((CSR_READ_4(sc, FXP_CSR_MDICONTROL) & 0x10000000) == 0 &&
	    count--)
		DELAY(10);

	if (count <= 0)
		printf("%s: fxp_mdi_write: timed out\n", sc->sc_dev.dv_xname);
}

int
fxp_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
	struct fxp_softc *sc = ifp->if_softc;
	struct ifreq *ifr = (struct ifreq *)data;
	int s, error;

	s = splnet();

	switch (cmd) {
	case SIOCSIFMEDIA:
	case SIOCGIFMEDIA:
		error = ifmedia_ioctl(ifp, ifr, &sc->sc_mii.mii_media, cmd);
		break;

	default:
		error = ether_ioctl(ifp, cmd, data);
		if (error == ENETRESET) {
			if (sc->sc_enabled) {
				/*
				 * Multicast list has changed; set the
				 * hardware filter accordingly.
				 */
				if (sc->sc_txpending) {
					sc->sc_flags |= FXPF_WANTINIT;
					error = 0;
				} else
					error = fxp_init(ifp);
			} else
				error = 0;
		}
		break;
	}

	/* Try to get more packets going. */
	if (sc->sc_enabled)
		fxp_start(ifp);

	splx(s);
	return (error);
}

/*
 * Program the multicast filter.
 *
 * This function must be called at splnet().
 */
void
fxp_mc_setup(struct fxp_softc *sc)
{
	struct fxp_cb_mcs *mcsp = &sc->sc_control_data->fcd_mcscb;
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	struct ethercom *ec = &sc->sc_ethercom;
	struct ether_multi *enm;
	struct ether_multistep step;
	int count, nmcasts;

#ifdef DIAGNOSTIC
	if (sc->sc_txpending)
		panic("fxp_mc_setup: pending transmissions");
#endif

	ifp->if_flags &= ~IFF_ALLMULTI;

	/*
	 * Initialize multicast setup descriptor.
	 */
	nmcasts = 0;
	ETHER_FIRST_MULTI(step, ec, enm);
	while (enm != NULL) {
		/*
		 * Check for too many multicast addresses or if we're
		 * listening to a range.  Either way, we simply have
		 * to accept all multicasts.
		 */
		if (nmcasts >= MAXMCADDR ||
		    memcmp(enm->enm_addrlo, enm->enm_addrhi,
		    ETHER_ADDR_LEN) != 0) {
			/*
			 * Callers of this function must do the
			 * right thing with this.  If we're called
			 * from outside fxp_init(), the caller must
			 * detect if the state if IFF_ALLMULTI changes.
			 * If it does, the caller must then call
			 * fxp_init(), since allmulti is handled by
			 * the config block.
			 */
			ifp->if_flags |= IFF_ALLMULTI;
			return;
		}
		memcpy((void *)&mcsp->mc_addr[nmcasts][0], enm->enm_addrlo,
		    ETHER_ADDR_LEN);
		nmcasts++;
		ETHER_NEXT_MULTI(step, enm);
	}

	/* BIG_ENDIAN: no need to swap to store 0 */
	mcsp->cb_status = 0;
	mcsp->cb_command = htole16(FXP_CB_COMMAND_MCAS | FXP_CB_COMMAND_EL);
	mcsp->link_addr = htole32(FXP_CDTXADDR(sc, FXP_NEXTTX(sc->sc_txlast)));
	mcsp->mc_cnt = htole16(nmcasts * ETHER_ADDR_LEN);

	FXP_CDMCSSYNC(sc, BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);

	/*
	 * Wait until the command unit is not active.  This should never
	 * happen since nothing is queued, but make sure anyway.
	 */
	count = 100;
	while ((CSR_READ_1(sc, FXP_CSR_SCB_RUSCUS) >> 6) ==
	    FXP_SCB_CUS_ACTIVE && --count)
		DELAY(1);
	if (count == 0) {
		printf("%s at line %d: command queue timeout\n",
		    sc->sc_dev.dv_xname, __LINE__);
		return;
	}

	/*
	 * Start the multicast setup command/DMA.
	 */
	fxp_scb_wait(sc);
	CSR_WRITE_4(sc, FXP_CSR_SCB_GENERAL, sc->sc_cddma + FXP_CDMCSOFF);
	fxp_scb_cmd(sc, FXP_SCB_COMMAND_CU_START);

	/* ...and wait for it to complete. */
	count = 1000;
	do {
		FXP_CDMCSSYNC(sc,
		    BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);
		DELAY(1);
	} while ((le16toh(mcsp->cb_status) & FXP_CB_STATUS_C) == 0 && --count);
	if (count == 0) {
		printf("%s at line %d: dmasync timeout\n",
		    sc->sc_dev.dv_xname, __LINE__);
		return;
	}
}

int
fxp_enable(struct fxp_softc *sc)
{

	if (sc->sc_enabled == 0 && sc->sc_enable != NULL) {
		if ((*sc->sc_enable)(sc) != 0) {
			printf("%s: device enable failed\n",
			    sc->sc_dev.dv_xname);
			return (EIO);
		}
	}

	sc->sc_enabled = 1;
	return (0);
}

void
fxp_disable(struct fxp_softc *sc)
{

	if (sc->sc_enabled != 0 && sc->sc_disable != NULL) {
		(*sc->sc_disable)(sc);
		sc->sc_enabled = 0;
	}
}

/*
 * fxp_activate:
 *
 *	Handle device activation/deactivation requests.
 */
int
fxp_activate(struct device *self, enum devact act)
{
	struct fxp_softc *sc = (void *) self;
	int s, error = 0;

	s = splnet();
	switch (act) {
	case DVACT_ACTIVATE:
		error = EOPNOTSUPP;
		break;

	case DVACT_DEACTIVATE:
		if (sc->sc_flags & FXPF_MII)
			mii_activate(&sc->sc_mii, act, MII_PHY_ANY,
			    MII_OFFSET_ANY);
		if_deactivate(&sc->sc_ethercom.ec_if);
		break;
	}
	splx(s);

	return (error);
}

/*
 * fxp_detach:
 *
 *	Detach an i82557 interface.
 */
int
fxp_detach(struct fxp_softc *sc)
{
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	int i;

	/* Succeed now if there's no work to do. */
	if ((sc->sc_flags & FXPF_ATTACHED) == 0)
		return (0);

	/* Unhook our tick handler. */
	callout_stop(&sc->sc_callout);

	if (sc->sc_flags & FXPF_MII) {
		/* Detach all PHYs */
		mii_detach(&sc->sc_mii, MII_PHY_ANY, MII_OFFSET_ANY);
	}

	/* Delete all remaining media. */
	ifmedia_delete_instance(&sc->sc_mii.mii_media, IFM_INST_ANY);

#if NRND > 0
	rnd_detach_source(&sc->rnd_source);
#endif
	ether_ifdetach(ifp);
	if_detach(ifp);

	for (i = 0; i < FXP_NRFABUFS; i++) {
		bus_dmamap_unload(sc->sc_dmat, sc->sc_rxmaps[i]);
		bus_dmamap_destroy(sc->sc_dmat, sc->sc_rxmaps[i]);
	}

	for (i = 0; i < FXP_NTXCB; i++) {
		bus_dmamap_unload(sc->sc_dmat, FXP_DSTX(sc, i)->txs_dmamap);
		bus_dmamap_destroy(sc->sc_dmat, FXP_DSTX(sc, i)->txs_dmamap);
	}

	bus_dmamap_unload(sc->sc_dmat, sc->sc_dmamap);
	bus_dmamap_destroy(sc->sc_dmat, sc->sc_dmamap);
	bus_dmamem_unmap(sc->sc_dmat, (caddr_t)sc->sc_control_data,
	    sizeof(struct fxp_control_data));
	bus_dmamem_free(sc->sc_dmat, &sc->sc_cdseg, sc->sc_cdnseg);

	shutdownhook_disestablish(sc->sc_sdhook);
	powerhook_disestablish(sc->sc_powerhook);

	return (0);
}