[dragonfly.git] / sys / dev / netif / xl / if_xl.c

/*
 * Copyright (c) 1997, 1998, 1999
 *      Bill Paul <wpaul@ctr.columbia.edu>.  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: src/sys/pci/if_xl.c,v 1.72.2.28 2003/10/08 06:01:57 murray Exp $
 * $DragonFly: src/sys/dev/netif/xl/if_xl.c,v 1.56 2008/09/17 08:51:29 sephe Exp $
 */

/*
 * 3Com 3c90x Etherlink XL PCI NIC driver
 *
 * Supports the 3Com "boomerang", "cyclone" and "hurricane" PCI
 * bus-master chips (3c90x cards and embedded controllers) including
 * the following:
 *
 * 3Com 3c900-TPO       10Mbps/RJ-45
 * 3Com 3c900-COMBO     10Mbps/RJ-45,AUI,BNC
 * 3Com 3c905-TX        10/100Mbps/RJ-45
 * 3Com 3c905-T4        10/100Mbps/RJ-45
 * 3Com 3c900B-TPO      10Mbps/RJ-45
 * 3Com 3c900B-COMBO    10Mbps/RJ-45,AUI,BNC
 * 3Com 3c900B-TPC      10Mbps/RJ-45,BNC
 * 3Com 3c900B-FL       10Mbps/Fiber-optic
 * 3Com 3c905B-COMBO    10/100Mbps/RJ-45,AUI,BNC
 * 3Com 3c905B-TX       10/100Mbps/RJ-45
 * 3Com 3c905B-FL/FX    10/100Mbps/Fiber-optic
 * 3Com 3c905C-TX       10/100Mbps/RJ-45 (Tornado ASIC)
 * 3Com 3c980-TX        10/100Mbps server adapter (Hurricane ASIC)
 * 3Com 3c980C-TX       10/100Mbps server adapter (Tornado ASIC)
 * 3Com 3cSOHO100-TX    10/100Mbps/RJ-45 (Hurricane ASIC)
 * 3Com 3c450-TX        10/100Mbps/RJ-45 (Tornado ASIC)
 * 3Com 3c555           10/100Mbps/RJ-45 (MiniPCI, Laptop Hurricane)
 * 3Com 3c556           10/100Mbps/RJ-45 (MiniPCI, Hurricane ASIC)
 * 3Com 3c556B          10/100Mbps/RJ-45 (MiniPCI, Hurricane ASIC)
 * 3Com 3c575TX         10/100Mbps/RJ-45 (Cardbus, Hurricane ASIC)
 * 3Com 3c575B          10/100Mbps/RJ-45 (Cardbus, Hurricane ASIC)
 * 3Com 3c575C          10/100Mbps/RJ-45 (Cardbus, Hurricane ASIC)
 * 3Com 3cxfem656       10/100Mbps/RJ-45 (Cardbus, Hurricane ASIC)
 * 3Com 3cxfem656b      10/100Mbps/RJ-45 (Cardbus, Hurricane ASIC)
 * 3Com 3cxfem656c      10/100Mbps/RJ-45 (Cardbus, Tornado ASIC)
 * Dell Optiplex GX1 on-board 3c918 10/100Mbps/RJ-45
 * Dell on-board 3c920 10/100Mbps/RJ-45
 * Dell Precision on-board 3c905B 10/100Mbps/RJ-45
 * Dell Latitude laptop docking station embedded 3c905-TX
 *
 * Written by Bill Paul <wpaul@ctr.columbia.edu>
 * Electrical Engineering Department
 * Columbia University, New York City
 */

/*
 * The 3c90x series chips use a bus-master DMA interface for transfering
 * packets to and from the controller chip. Some of the "vortex" cards
 * (3c59x) also supported a bus master mode, however for those chips
 * you could only DMA packets to/from a contiguous memory buffer. For
 * transmission this would mean copying the contents of the queued mbuf
 * chain into an mbuf cluster and then DMAing the cluster. This extra
 * copy would sort of defeat the purpose of the bus master support for
 * any packet that doesn't fit into a single mbuf.
 *
 * By contrast, the 3c90x cards support a fragment-based bus master
 * mode where mbuf chains can be encapsulated using TX descriptors.
 * This is similar to other PCI chips such as the Texas Instruments
 * ThunderLAN and the Intel 82557/82558.
 *
 * The "vortex" driver (if_vx.c) happens to work for the "boomerang"
 * bus master chips because they maintain the old PIO interface for
 * backwards compatibility, but starting with the 3c905B and the
 * "cyclone" chips, the compatibility interface has been dropped.
 * Since using bus master DMA is a big win, we use this driver to
 * support the PCI "boomerang" chips even though they work with the
 * "vortex" driver in order to obtain better performance.
 */

#include "opt_polling.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sockio.h>
#include <sys/endian.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/serialize.h>
#include <sys/bus.h>
#include <sys/rman.h>
#include <sys/thread2.h>
#include <sys/interrupt.h>

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

#include <net/bpf.h>

#include "../mii_layer/mii.h"
#include "../mii_layer/miivar.h"

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

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

#include "if_xlreg.h"

#define XL905B_CSUM_FEATURES    (CSUM_IP | CSUM_TCP | CSUM_UDP)

/*
 * Various supported device vendors/types and their names.
 */
static struct xl_type xl_devs[] = {
        { TC_VENDORID, TC_DEVICEID_BOOMERANG_10BT,
                "3Com 3c900-TPO Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_BOOMERANG_10BT_COMBO,
                "3Com 3c900-COMBO Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_BOOMERANG_10_100BT,
                "3Com 3c905-TX Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_BOOMERANG_100BT4,
                "3Com 3c905-T4 Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_KRAKATOA_10BT,
                "3Com 3c900B-TPO Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_KRAKATOA_10BT_COMBO,
                "3Com 3c900B-COMBO Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_KRAKATOA_10BT_TPC,
                "3Com 3c900B-TPC Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_CYCLONE_10FL,
                "3Com 3c900B-FL Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_10_100BT,
                "3Com 3c905B-TX Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_CYCLONE_10_100BT4,
                "3Com 3c905B-T4 Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_CYCLONE_10_100FX,
                "3Com 3c905B-FX/SC Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_CYCLONE_10_100_COMBO,
                "3Com 3c905B-COMBO Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_TORNADO_10_100BT,
                "3Com 3c905C-TX Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_TORNADO_10_100BT_920B,
                "3Com 3c920B-EMB Integrated Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_10_100BT_SERV,
                "3Com 3c980 Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_TORNADO_10_100BT_SERV,
                "3Com 3c980C Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_SOHO100TX,
                "3Com 3cSOHO100-TX OfficeConnect" },
        { TC_VENDORID, TC_DEVICEID_TORNADO_HOMECONNECT,
                "3Com 3c450-TX HomeConnect" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_555,
                "3Com 3c555 Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_556,
                "3Com 3c556 Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_556B,
                "3Com 3c556B Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_575A,
                "3Com 3c575TX Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_575B,
                "3Com 3c575B Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_575C,
                "3Com 3c575C Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_656,
                "3Com 3c656 Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_HURRICANE_656B,
                "3Com 3c656B Fast Etherlink XL" },
        { TC_VENDORID, TC_DEVICEID_TORNADO_656C,
                "3Com 3c656C Fast Etherlink XL" },
        { 0, 0, NULL }
};

static int xl_probe             (device_t);
static int xl_attach            (device_t);
static int xl_detach            (device_t);
static void xl_shutdown         (device_t);
static int xl_suspend           (device_t); 
static int xl_resume            (device_t);

static int xl_newbuf            (struct xl_softc *, struct xl_chain_onefrag *,
                                 int);
static void xl_stats_update     (void *);
static void xl_stats_update_serialized(void *);
static int xl_encap             (struct xl_softc *, struct xl_chain *,
                                                struct mbuf *);
static void xl_rxeof            (struct xl_softc *, int);
static int xl_rx_resync         (struct xl_softc *);
static void xl_txeof            (struct xl_softc *);
static void xl_txeof_90xB       (struct xl_softc *);
static void xl_txeoc            (struct xl_softc *);
static void xl_intr             (void *);
static void xl_start_body       (struct ifnet *, int);
static void xl_start            (struct ifnet *);
static void xl_start_90xB       (struct ifnet *);
static int xl_ioctl             (struct ifnet *, u_long, caddr_t,
                                                struct ucred *);
static void xl_init             (void *);
static void xl_stop             (struct xl_softc *);
static void xl_watchdog         (struct ifnet *);
#ifdef DEVICE_POLLING
static void xl_start_poll       (struct ifnet *);
static void xl_poll             (struct ifnet *, enum poll_cmd, int);
#endif
static void xl_enable_intrs     (struct xl_softc *, uint16_t);

static int xl_ifmedia_upd       (struct ifnet *);
static void xl_ifmedia_sts      (struct ifnet *, struct ifmediareq *);

static int xl_eeprom_wait       (struct xl_softc *);
static int xl_read_eeprom       (struct xl_softc *, caddr_t, int, int, int);
static void xl_mii_sync         (struct xl_softc *);
static void xl_mii_send         (struct xl_softc *, u_int32_t, int);
static int xl_mii_readreg       (struct xl_softc *, struct xl_mii_frame *);
static int xl_mii_writereg      (struct xl_softc *, struct xl_mii_frame *);

static void xl_setcfg           (struct xl_softc *);
static void xl_setmode          (struct xl_softc *, int);
static void xl_setmulti         (struct xl_softc *);
static void xl_setmulti_hash    (struct xl_softc *);
static void xl_reset            (struct xl_softc *);
static int xl_list_rx_init      (struct xl_softc *);
static void xl_list_tx_init     (struct xl_softc *);
static void xl_list_tx_init_90xB(struct xl_softc *);
static void xl_wait             (struct xl_softc *);
static void xl_mediacheck       (struct xl_softc *);
static void xl_choose_xcvr      (struct xl_softc *, int);

static int xl_dma_alloc         (device_t);
static void xl_dma_free         (device_t);

#ifdef notdef
static void xl_testpacket       (struct xl_softc *);
#endif

static int xl_miibus_readreg    (device_t, int, int);
static int xl_miibus_writereg   (device_t, int, int, int);
static void xl_miibus_statchg   (device_t);
static void xl_miibus_mediainit (device_t);

static device_method_t xl_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         xl_probe),
        DEVMETHOD(device_attach,        xl_attach),
        DEVMETHOD(device_detach,        xl_detach),
        DEVMETHOD(device_shutdown,      xl_shutdown),
        DEVMETHOD(device_suspend,       xl_suspend),
        DEVMETHOD(device_resume,        xl_resume),

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

        /* MII interface */
        DEVMETHOD(miibus_readreg,       xl_miibus_readreg),
        DEVMETHOD(miibus_writereg,      xl_miibus_writereg),
        DEVMETHOD(miibus_statchg,       xl_miibus_statchg),
        DEVMETHOD(miibus_mediainit,     xl_miibus_mediainit),

        { 0, 0 }
};

static driver_t xl_driver = {
        "xl",
        xl_methods,
        sizeof(struct xl_softc)
};

static devclass_t xl_devclass;

DECLARE_DUMMY_MODULE(if_xl);
MODULE_DEPEND(if_xl, miibus, 1, 1, 1);
DRIVER_MODULE(if_xl, pci, xl_driver, xl_devclass, 0, 0);
DRIVER_MODULE(if_xl, cardbus, xl_driver, xl_devclass, 0, 0);
DRIVER_MODULE(miibus, xl, miibus_driver, miibus_devclass, 0, 0);

static void
xl_enable_intrs(struct xl_softc *sc, uint16_t intrs)
{
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ACK | 0xFF);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB | intrs);
        if (sc->xl_flags & XL_FLAG_FUNCREG)
                bus_space_write_4(sc->xl_ftag, sc->xl_fhandle, 4, 0x8000);
}

/*
 * Murphy's law says that it's possible the chip can wedge and
 * the 'command in progress' bit may never clear. Hence, we wait
 * only a finite amount of time to avoid getting caught in an
 * infinite loop. Normally this delay routine would be a macro,
 * but it isn't called during normal operation so we can afford
 * to make it a function.
 */
static void
xl_wait(struct xl_softc *sc)
{
        int             i;

        for (i = 0; i < XL_TIMEOUT; i++) {
                if (!(CSR_READ_2(sc, XL_STATUS) & XL_STAT_CMDBUSY))
                        break;
        }

        if (i == XL_TIMEOUT)
                if_printf(&sc->arpcom.ac_if, "command never completed!");

        return;
}

/*
 * MII access routines are provided for adapters with external
 * PHYs (3c905-TX, 3c905-T4, 3c905B-T4) and those with built-in
 * autoneg logic that's faked up to look like a PHY (3c905B-TX).
 * Note: if you don't perform the MDIO operations just right,
 * it's possible to end up with code that works correctly with
 * some chips/CPUs/processor speeds/bus speeds/etc but not
 * with others.
 */
#define MII_SET(x)                                      \
        CSR_WRITE_2(sc, XL_W4_PHY_MGMT,                 \
                CSR_READ_2(sc, XL_W4_PHY_MGMT) | (x))

#define MII_CLR(x)                                      \
        CSR_WRITE_2(sc, XL_W4_PHY_MGMT,                 \
                CSR_READ_2(sc, XL_W4_PHY_MGMT) & ~(x))

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

        XL_SEL_WIN(4);
        MII_SET(XL_MII_DIR|XL_MII_DATA);

        for (i = 0; i < 32; i++) {
                MII_SET(XL_MII_CLK);
                MII_SET(XL_MII_DATA);
                MII_SET(XL_MII_DATA);
                MII_CLR(XL_MII_CLK);
                MII_SET(XL_MII_DATA);
                MII_SET(XL_MII_DATA);
        }

        return;
}

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

        XL_SEL_WIN(4);
        MII_CLR(XL_MII_CLK);

        for (i = (0x1 << (cnt - 1)); i; i >>= 1) {
                if (bits & i) {
                        MII_SET(XL_MII_DATA);
                } else {
                        MII_CLR(XL_MII_DATA);
                }
                MII_CLR(XL_MII_CLK);
                MII_SET(XL_MII_CLK);
        }
}

/*
 * Read an PHY register through the MII.
 */
static int
xl_mii_readreg(struct xl_softc *sc, struct xl_mii_frame *frame)
{
        int                     i, ack;

        /*
         * Set up frame for RX.
         */
        frame->mii_stdelim = XL_MII_STARTDELIM;
        frame->mii_opcode = XL_MII_READOP;
        frame->mii_turnaround = 0;
        frame->mii_data = 0;
        
        /*
         * Select register window 4.
         */

        XL_SEL_WIN(4);

        CSR_WRITE_2(sc, XL_W4_PHY_MGMT, 0);
        /*
         * Turn on data xmit.
         */
        MII_SET(XL_MII_DIR);

        xl_mii_sync(sc);

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

        /* Idle bit */
        MII_CLR((XL_MII_CLK|XL_MII_DATA));
        MII_SET(XL_MII_CLK);

        /* Turn off xmit. */
        MII_CLR(XL_MII_DIR);

        /* Check for ack */
        MII_CLR(XL_MII_CLK);
        ack = CSR_READ_2(sc, XL_W4_PHY_MGMT) & XL_MII_DATA;
        MII_SET(XL_MII_CLK);

        /*
         * 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++) {
                        MII_CLR(XL_MII_CLK);
                        MII_SET(XL_MII_CLK);
                }
                goto fail;
        }

        for (i = 0x8000; i; i >>= 1) {
                MII_CLR(XL_MII_CLK);
                if (!ack) {
                        if (CSR_READ_2(sc, XL_W4_PHY_MGMT) & XL_MII_DATA)
                                frame->mii_data |= i;
                }
                MII_SET(XL_MII_CLK);
        }

fail:

        MII_CLR(XL_MII_CLK);
        MII_SET(XL_MII_CLK);

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

/*
 * Write to a PHY register through the MII.
 */
static int
xl_mii_writereg(struct xl_softc *sc, struct xl_mii_frame *frame)
{
        /*
         * Set up frame for TX.
         */

        frame->mii_stdelim = XL_MII_STARTDELIM;
        frame->mii_opcode = XL_MII_WRITEOP;
        frame->mii_turnaround = XL_MII_TURNAROUND;
        
        /*
         * Select the window 4.
         */
        XL_SEL_WIN(4);

        /*
         * Turn on data output.
         */
        MII_SET(XL_MII_DIR);

        xl_mii_sync(sc);

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

        /* Idle bit. */
        MII_SET(XL_MII_CLK);
        MII_CLR(XL_MII_CLK);

        /*
         * Turn off xmit.
         */
        MII_CLR(XL_MII_DIR);

        return(0);
}

static int
xl_miibus_readreg(device_t dev, int phy, int reg)
{
        struct xl_softc         *sc;
        struct xl_mii_frame     frame;

        sc = device_get_softc(dev);

        /*
         * Pretend that PHYs are only available at MII address 24.
         * This is to guard against problems with certain 3Com ASIC
         * revisions that incorrectly map the internal transceiver
         * control registers at all MII addresses. This can cause
         * the miibus code to attach the same PHY several times over.
         */
        if ((!(sc->xl_flags & XL_FLAG_PHYOK)) && phy != 24)
                return(0);

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

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

        return(frame.mii_data);
}

static int
xl_miibus_writereg(device_t dev, int phy, int reg, int data)
{
        struct xl_softc         *sc;
        struct xl_mii_frame     frame;

        sc = device_get_softc(dev);

        if ((!(sc->xl_flags & XL_FLAG_PHYOK)) && phy != 24)
                return(0);

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

        frame.mii_phyaddr = phy;
        frame.mii_regaddr = reg;
        frame.mii_data = data;

        xl_mii_writereg(sc, &frame);

        return(0);
}

static void
xl_miibus_statchg(device_t dev)
{
        struct xl_softc         *sc;
        struct mii_data         *mii;

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

        ASSERT_SERIALIZED(sc->arpcom.ac_if.if_serializer);

        xl_setcfg(sc);

        /* Set ASIC's duplex mode to match the PHY. */
        XL_SEL_WIN(3);
        if ((mii->mii_media_active & IFM_GMASK) == IFM_FDX)
                CSR_WRITE_1(sc, XL_W3_MAC_CTRL, XL_MACCTRL_DUPLEX);
        else
                CSR_WRITE_1(sc, XL_W3_MAC_CTRL,
                        (CSR_READ_1(sc, XL_W3_MAC_CTRL) & ~XL_MACCTRL_DUPLEX));
}

/*
 * Special support for the 3c905B-COMBO. This card has 10/100 support
 * plus BNC and AUI ports. This means we will have both an miibus attached
 * plus some non-MII media settings. In order to allow this, we have to
 * add the extra media to the miibus's ifmedia struct, but we can't do
 * that during xl_attach() because the miibus hasn't been attached yet.
 * So instead, we wait until the miibus probe/attach is done, at which
 * point we will get a callback telling is that it's safe to add our
 * extra media.
 */
static void
xl_miibus_mediainit(device_t dev)
{
        struct xl_softc         *sc;
        struct mii_data         *mii;
        struct ifmedia          *ifm;
        
        sc = device_get_softc(dev);
        mii = device_get_softc(sc->xl_miibus);
        ifm = &mii->mii_media;

        if (sc->xl_media & (XL_MEDIAOPT_AUI|XL_MEDIAOPT_10FL)) {
                /*
                 * Check for a 10baseFL board in disguise.
                 */
                if (sc->xl_type == XL_TYPE_905B &&
                    sc->xl_media == XL_MEDIAOPT_10FL) {
                        if (bootverbose)
                                device_printf(dev, "found 10baseFL\n");
                        ifmedia_add(ifm, IFM_ETHER|IFM_10_FL, 0, NULL);
                        ifmedia_add(ifm, IFM_ETHER|IFM_10_FL|IFM_HDX, 0, NULL);
                        if (sc->xl_caps & XL_CAPS_FULL_DUPLEX)
                                ifmedia_add(ifm,
                                    IFM_ETHER|IFM_10_FL|IFM_FDX, 0, NULL);
                } else {
                        if (bootverbose)
                                device_printf(dev, "found AUI\n");
                        ifmedia_add(ifm, IFM_ETHER|IFM_10_5, 0, NULL);
                }
        }

        if (sc->xl_media & XL_MEDIAOPT_BNC) {
                if (bootverbose)
                        device_printf(dev, "found BNC\n");
                ifmedia_add(ifm, IFM_ETHER|IFM_10_2, 0, NULL);
        }

        return;
}

/*
 * The EEPROM is slow: give it time to come ready after issuing
 * it a command.
 */
static int
xl_eeprom_wait(struct xl_softc *sc)
{
        int                     i;

        for (i = 0; i < 100; i++) {
                if (CSR_READ_2(sc, XL_W0_EE_CMD) & XL_EE_BUSY)
                        DELAY(162);
                else
                        break;
        }

        if (i == 100) {
                if_printf(&sc->arpcom.ac_if, "eeprom failed to come ready\n");
                return(1);
        }

        return(0);
}

/*
 * Read a sequence of words from the EEPROM. Note that ethernet address
 * data is stored in the EEPROM in network byte order.
 */
static int
xl_read_eeprom(struct xl_softc *sc, caddr_t dest, int off, int cnt, int swap)
{
        int                     err = 0, i;
        u_int16_t               word = 0, *ptr;
#define EEPROM_5BIT_OFFSET(A) ((((A) << 2) & 0x7F00) | ((A) & 0x003F))
#define EEPROM_8BIT_OFFSET(A) ((A) & 0x003F)
        /* WARNING! DANGER!
         * It's easy to accidentally overwrite the rom content!
         * Note: the 3c575 uses 8bit EEPROM offsets.
         */
        XL_SEL_WIN(0);

        if (xl_eeprom_wait(sc))
                return(1);

        if (sc->xl_flags & XL_FLAG_EEPROM_OFFSET_30)
                off += 0x30;

        for (i = 0; i < cnt; i++) {
                if (sc->xl_flags & XL_FLAG_8BITROM)
                        CSR_WRITE_2(sc, XL_W0_EE_CMD, 
                            XL_EE_8BIT_READ | EEPROM_8BIT_OFFSET(off + i));
                else
                        CSR_WRITE_2(sc, XL_W0_EE_CMD,
                            XL_EE_READ | EEPROM_5BIT_OFFSET(off + i));
                err = xl_eeprom_wait(sc);
                if (err)
                        break;
                word = CSR_READ_2(sc, XL_W0_EE_DATA);
                ptr = (u_int16_t *)(dest + (i * 2));
                if (swap)
                        *ptr = ntohs(word);
                else
                        *ptr = word;    
        }

        return(err ? 1 : 0);
}

/*
 * NICs older than the 3c905B have only one multicast option, which
 * is to enable reception of all multicast frames.
 */
static void
xl_setmulti(struct xl_softc *sc)
{
        struct ifnet            *ifp;
        struct ifmultiaddr      *ifma;
        u_int8_t                rxfilt;
        int                     mcnt = 0;

        ifp = &sc->arpcom.ac_if;

        XL_SEL_WIN(5);
        rxfilt = CSR_READ_1(sc, XL_W5_RX_FILTER);

        if (ifp->if_flags & IFF_ALLMULTI) {
                rxfilt |= XL_RXFILTER_ALLMULTI;
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_FILT|rxfilt);
                return;
        }

        TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link)
                mcnt++;

        if (mcnt)
                rxfilt |= XL_RXFILTER_ALLMULTI;
        else
                rxfilt &= ~XL_RXFILTER_ALLMULTI;

        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_FILT|rxfilt);

        return;
}

/*
 * 3c905B adapters have a hash filter that we can program.
 */
static void
xl_setmulti_hash(struct xl_softc *sc)
{
        struct ifnet            *ifp;
        int                     h = 0, i;
        struct ifmultiaddr      *ifma;
        u_int8_t                rxfilt;
        int                     mcnt = 0;

        ifp = &sc->arpcom.ac_if;

        XL_SEL_WIN(5);
        rxfilt = CSR_READ_1(sc, XL_W5_RX_FILTER);

        if (ifp->if_flags & IFF_ALLMULTI) {
                rxfilt |= XL_RXFILTER_ALLMULTI;
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_FILT|rxfilt);
                return;
        } else
                rxfilt &= ~XL_RXFILTER_ALLMULTI;


        /* first, zot all the existing hash bits */
        for (i = 0; i < XL_HASHFILT_SIZE; i++)
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_HASH|i);

        /* now program new ones */
        TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
                if (ifma->ifma_addr->sa_family != AF_LINK)
                        continue;

                /*
                 * Note: the 3c905B currently only supports a 64-bit
                 * hash table, which means we really only need 6 bits,
                 * but the manual indicates that future chip revisions
                 * will have a 256-bit hash table, hence the routine is
                 * set up to calculate 8 bits of position info in case
                 * we need it some day.
                 * Note II, The Sequel: _CURRENT_ versions of the 3c905B
                 * have a 256 bit hash table. This means we have to use
                 * all 8 bits regardless.  On older cards, the upper 2
                 * bits will be ignored. Grrrr....
                 */
                h = ether_crc32_be(
                        LLADDR((struct sockaddr_dl *)ifma->ifma_addr),
                        ETHER_ADDR_LEN) & 0xff;
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_HASH|XL_HASH_SET|h);
                mcnt++;
        }

        if (mcnt)
                rxfilt |= XL_RXFILTER_MULTIHASH;
        else
                rxfilt &= ~XL_RXFILTER_MULTIHASH;

        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_FILT|rxfilt);

        return;
}

#ifdef notdef
static void
xl_testpacket(struct xl_softc *sc)
{
        struct mbuf             *m;
        struct ifnet            *ifp;

        ifp = &sc->arpcom.ac_if;

        MGETHDR(m, MB_DONTWAIT, MT_DATA);

        if (m == NULL)
                return;

        bcopy(&sc->arpcom.ac_enaddr,
                mtod(m, struct ether_header *)->ether_dhost, ETHER_ADDR_LEN);
        bcopy(&sc->arpcom.ac_enaddr,
                mtod(m, struct ether_header *)->ether_shost, ETHER_ADDR_LEN);
        mtod(m, struct ether_header *)->ether_type = htons(3);
        mtod(m, unsigned char *)[14] = 0;
        mtod(m, unsigned char *)[15] = 0;
        mtod(m, unsigned char *)[16] = 0xE3;
        m->m_len = m->m_pkthdr.len = sizeof(struct ether_header) + 3;
        IF_ENQUEUE(&ifp->if_snd, m);
        xl_start(ifp);

        return;
}
#endif

static void
xl_setcfg(struct xl_softc *sc)
{
        u_int32_t               icfg;

        XL_SEL_WIN(3);
        icfg = CSR_READ_4(sc, XL_W3_INTERNAL_CFG);
        icfg &= ~XL_ICFG_CONNECTOR_MASK;
        if (sc->xl_media & XL_MEDIAOPT_MII ||
                sc->xl_media & XL_MEDIAOPT_BT4)
                icfg |= (XL_XCVR_MII << XL_ICFG_CONNECTOR_BITS);
        if (sc->xl_media & XL_MEDIAOPT_BTX)
                icfg |= (XL_XCVR_AUTO << XL_ICFG_CONNECTOR_BITS);

        CSR_WRITE_4(sc, XL_W3_INTERNAL_CFG, icfg);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_COAX_STOP);

        return;
}

static void
xl_setmode(struct xl_softc *sc, int media)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        u_int32_t               icfg;
        u_int16_t               mediastat;

        if_printf(ifp, "selecting ");

        XL_SEL_WIN(4);
        mediastat = CSR_READ_2(sc, XL_W4_MEDIA_STATUS);
        XL_SEL_WIN(3);
        icfg = CSR_READ_4(sc, XL_W3_INTERNAL_CFG);

        if (sc->xl_media & XL_MEDIAOPT_BT) {
                if (IFM_SUBTYPE(media) == IFM_10_T) {
                        kprintf("10baseT transceiver, ");
                        sc->xl_xcvr = XL_XCVR_10BT;
                        icfg &= ~XL_ICFG_CONNECTOR_MASK;
                        icfg |= (XL_XCVR_10BT << XL_ICFG_CONNECTOR_BITS);
                        mediastat |= XL_MEDIASTAT_LINKBEAT|
                                        XL_MEDIASTAT_JABGUARD;
                        mediastat &= ~XL_MEDIASTAT_SQEENB;
                }
        }

        if (sc->xl_media & XL_MEDIAOPT_BFX) {
                if (IFM_SUBTYPE(media) == IFM_100_FX) {
                        kprintf("100baseFX port, ");
                        sc->xl_xcvr = XL_XCVR_100BFX;
                        icfg &= ~XL_ICFG_CONNECTOR_MASK;
                        icfg |= (XL_XCVR_100BFX << XL_ICFG_CONNECTOR_BITS);
                        mediastat |= XL_MEDIASTAT_LINKBEAT;
                        mediastat &= ~XL_MEDIASTAT_SQEENB;
                }
        }

        if (sc->xl_media & (XL_MEDIAOPT_AUI|XL_MEDIAOPT_10FL)) {
                if (IFM_SUBTYPE(media) == IFM_10_5) {
                        kprintf("AUI port, ");
                        sc->xl_xcvr = XL_XCVR_AUI;
                        icfg &= ~XL_ICFG_CONNECTOR_MASK;
                        icfg |= (XL_XCVR_AUI << XL_ICFG_CONNECTOR_BITS);
                        mediastat &= ~(XL_MEDIASTAT_LINKBEAT|
                                        XL_MEDIASTAT_JABGUARD);
                        mediastat |= ~XL_MEDIASTAT_SQEENB;
                }
                if (IFM_SUBTYPE(media) == IFM_10_FL) {
                        kprintf("10baseFL transceiver, ");
                        sc->xl_xcvr = XL_XCVR_AUI;
                        icfg &= ~XL_ICFG_CONNECTOR_MASK;
                        icfg |= (XL_XCVR_AUI << XL_ICFG_CONNECTOR_BITS);
                        mediastat &= ~(XL_MEDIASTAT_LINKBEAT|
                                        XL_MEDIASTAT_JABGUARD);
                        mediastat |= ~XL_MEDIASTAT_SQEENB;
                }
        }

        if (sc->xl_media & XL_MEDIAOPT_BNC) {
                if (IFM_SUBTYPE(media) == IFM_10_2) {
                        kprintf("BNC port, ");
                        sc->xl_xcvr = XL_XCVR_COAX;
                        icfg &= ~XL_ICFG_CONNECTOR_MASK;
                        icfg |= (XL_XCVR_COAX << XL_ICFG_CONNECTOR_BITS);
                        mediastat &= ~(XL_MEDIASTAT_LINKBEAT|
                                        XL_MEDIASTAT_JABGUARD|
                                        XL_MEDIASTAT_SQEENB);
                }
        }

        if ((media & IFM_GMASK) == IFM_FDX ||
                        IFM_SUBTYPE(media) == IFM_100_FX) {
                kprintf("full duplex\n");
                XL_SEL_WIN(3);
                CSR_WRITE_1(sc, XL_W3_MAC_CTRL, XL_MACCTRL_DUPLEX);
        } else {
                kprintf("half duplex\n");
                XL_SEL_WIN(3);
                CSR_WRITE_1(sc, XL_W3_MAC_CTRL,
                        (CSR_READ_1(sc, XL_W3_MAC_CTRL) & ~XL_MACCTRL_DUPLEX));
        }

        if (IFM_SUBTYPE(media) == IFM_10_2)
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_COAX_START);
        else
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_COAX_STOP);
        CSR_WRITE_4(sc, XL_W3_INTERNAL_CFG, icfg);
        XL_SEL_WIN(4);
        CSR_WRITE_2(sc, XL_W4_MEDIA_STATUS, mediastat);
        DELAY(800);
        XL_SEL_WIN(7);
}

static void
xl_reset(struct xl_softc *sc)
{
        int             i;

        XL_SEL_WIN(0);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RESET | 
                    ((sc->xl_flags & XL_FLAG_WEIRDRESET) ?
                     XL_RESETOPT_DISADVFD:0));

        /*
         * If we're using memory mapped register mode, pause briefly
         * after issuing the reset command before trying to access any
         * other registers. With my 3c575C cardbus card, failing to do
         * this results in the system locking up while trying to poll
         * the command busy bit in the status register.
         */
        if (sc->xl_flags & XL_FLAG_USE_MMIO)
                DELAY(100000);

        for (i = 0; i < XL_TIMEOUT; i++) {
                DELAY(10);
                if (!(CSR_READ_2(sc, XL_STATUS) & XL_STAT_CMDBUSY))
                        break;
        }

        if (i == XL_TIMEOUT)
                if_printf(&sc->arpcom.ac_if, "reset didn't complete\n");

        /* Reset TX and RX. */
        /* Note: the RX reset takes an absurd amount of time
         * on newer versions of the Tornado chips such as those
         * on the 3c905CX and newer 3c908C cards. We wait an
         * extra amount of time so that xl_wait() doesn't complain
         * and annoy the users.
         */
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_RESET);
        DELAY(100000);
        xl_wait(sc);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_RESET);
        xl_wait(sc);

        if (sc->xl_flags & XL_FLAG_INVERT_LED_PWR || 
            sc->xl_flags & XL_FLAG_INVERT_MII_PWR) {
                XL_SEL_WIN(2);
                CSR_WRITE_2(sc, XL_W2_RESET_OPTIONS, CSR_READ_2(sc,
                    XL_W2_RESET_OPTIONS) 
                    | ((sc->xl_flags & XL_FLAG_INVERT_LED_PWR)?XL_RESETOPT_INVERT_LED:0)
                    | ((sc->xl_flags & XL_FLAG_INVERT_MII_PWR)?XL_RESETOPT_INVERT_MII:0)
                    );
        }

        /* Wait a little while for the chip to get its brains in order. */
        DELAY(100000);
        return;
}

/*
 * Probe for a 3Com Etherlink XL chip. Check the PCI vendor and device
 * IDs against our list and return a device name if we find a match.
 */
static int
xl_probe(device_t dev)
{
        struct xl_type *t;
        uint16_t vid, did;

        vid = pci_get_vendor(dev);
        did = pci_get_device(dev);
        for (t = xl_devs; t->xl_name != NULL; t++) {
                if (vid == t->xl_vid && did == t->xl_did) {
                        device_set_desc(dev, t->xl_name);
                        return(0);
                }
        }
        return(ENXIO);
}

/*
 * This routine is a kludge to work around possible hardware faults
 * or manufacturing defects that can cause the media options register
 * (or reset options register, as it's called for the first generation
 * 3c90x adapters) to return an incorrect result. I have encountered
 * one Dell Latitude laptop docking station with an integrated 3c905-TX
 * which doesn't have any of the 'mediaopt' bits set. This screws up
 * the attach routine pretty badly because it doesn't know what media
 * to look for. If we find ourselves in this predicament, this routine
 * will try to guess the media options values and warn the user of a
 * possible manufacturing defect with his adapter/system/whatever.
 */
static void
xl_mediacheck(struct xl_softc *sc)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;

        /*
         * If some of the media options bits are set, assume they are
         * correct. If not, try to figure it out down below.
         * XXX I should check for 10baseFL, but I don't have an adapter
         * to test with.
         */
        if (sc->xl_media & (XL_MEDIAOPT_MASK & ~XL_MEDIAOPT_VCO)) {
                /*
                 * Check the XCVR value. If it's not in the normal range
                 * of values, we need to fake it up here.
                 */
                if (sc->xl_xcvr <= XL_XCVR_AUTO)
                        return;
                else {
                        if_printf(ifp, "bogus xcvr value in EEPROM (%x)\n",
                            sc->xl_xcvr);
                        if_printf(ifp,
                            "choosing new default based on card type\n");
                }
        } else {
                if (sc->xl_type == XL_TYPE_905B &&
                    sc->xl_media & XL_MEDIAOPT_10FL)
                        return;
                if_printf(ifp, "WARNING: no media options bits set in "
                        "the media options register!!\n");
                if_printf(ifp, "this could be a manufacturing defect in "
                        "your adapter or system\n");
                if_printf(ifp, "attempting to guess media type; you "
                        "should probably consult your vendor\n");
        }

        xl_choose_xcvr(sc, 1);
}

static void
xl_choose_xcvr(struct xl_softc *sc, int verbose)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        u_int16_t               devid;

        /*
         * Read the device ID from the EEPROM.
         * This is what's loaded into the PCI device ID register, so it has
         * to be correct otherwise we wouldn't have gotten this far.
         */
        xl_read_eeprom(sc, (caddr_t)&devid, XL_EE_PRODID, 1, 0);

        switch(devid) {
        case TC_DEVICEID_BOOMERANG_10BT:        /* 3c900-TPO */
        case TC_DEVICEID_KRAKATOA_10BT:         /* 3c900B-TPO */
                sc->xl_media = XL_MEDIAOPT_BT;
                sc->xl_xcvr = XL_XCVR_10BT;
                if (verbose)
                        if_printf(ifp, "guessing 10BaseT transceiver\n");
                break;
        case TC_DEVICEID_BOOMERANG_10BT_COMBO:  /* 3c900-COMBO */
        case TC_DEVICEID_KRAKATOA_10BT_COMBO:   /* 3c900B-COMBO */
                sc->xl_media = XL_MEDIAOPT_BT|XL_MEDIAOPT_BNC|XL_MEDIAOPT_AUI;
                sc->xl_xcvr = XL_XCVR_10BT;
                if (verbose)
                        if_printf(ifp, "guessing COMBO (AUI/BNC/TP)\n");
                break;
        case TC_DEVICEID_KRAKATOA_10BT_TPC:     /* 3c900B-TPC */
                sc->xl_media = XL_MEDIAOPT_BT|XL_MEDIAOPT_BNC;
                sc->xl_xcvr = XL_XCVR_10BT;
                if (verbose)
                        if_printf(ifp, "guessing TPC (BNC/TP)\n");
                break;
        case TC_DEVICEID_CYCLONE_10FL:          /* 3c900B-FL */
                sc->xl_media = XL_MEDIAOPT_10FL;
                sc->xl_xcvr = XL_XCVR_AUI;
                if (verbose)
                        if_printf(ifp, "guessing 10baseFL\n");
                break;
        case TC_DEVICEID_BOOMERANG_10_100BT:    /* 3c905-TX */
        case TC_DEVICEID_HURRICANE_555:         /* 3c555 */
        case TC_DEVICEID_HURRICANE_556:         /* 3c556 */
        case TC_DEVICEID_HURRICANE_556B:        /* 3c556B */
        case TC_DEVICEID_HURRICANE_575A:        /* 3c575TX */
        case TC_DEVICEID_HURRICANE_575B:        /* 3c575B */
        case TC_DEVICEID_HURRICANE_575C:        /* 3c575C */
        case TC_DEVICEID_HURRICANE_656:         /* 3c656 */
        case TC_DEVICEID_HURRICANE_656B:        /* 3c656B */
        case TC_DEVICEID_TORNADO_656C:          /* 3c656C */
        case TC_DEVICEID_TORNADO_10_100BT_920B: /* 3c920B-EMB */
                sc->xl_media = XL_MEDIAOPT_MII;
                sc->xl_xcvr = XL_XCVR_MII;
                if (verbose)
                        if_printf(ifp, "guessing MII\n");
                break;
        case TC_DEVICEID_BOOMERANG_100BT4:      /* 3c905-T4 */
        case TC_DEVICEID_CYCLONE_10_100BT4:     /* 3c905B-T4 */
                sc->xl_media = XL_MEDIAOPT_BT4;
                sc->xl_xcvr = XL_XCVR_MII;
                if (verbose)
                        if_printf(ifp, "guessing 100BaseT4/MII\n");
                break;
        case TC_DEVICEID_HURRICANE_10_100BT:    /* 3c905B-TX */
        case TC_DEVICEID_HURRICANE_10_100BT_SERV:/*3c980-TX */
        case TC_DEVICEID_TORNADO_10_100BT_SERV: /* 3c980C-TX */
        case TC_DEVICEID_HURRICANE_SOHO100TX:   /* 3cSOHO100-TX */
        case TC_DEVICEID_TORNADO_10_100BT:      /* 3c905C-TX */
        case TC_DEVICEID_TORNADO_HOMECONNECT:   /* 3c450-TX */
                sc->xl_media = XL_MEDIAOPT_BTX;
                sc->xl_xcvr = XL_XCVR_AUTO;
                if (verbose)
                        if_printf(ifp, "guessing 10/100 internal\n");
                break;
        case TC_DEVICEID_CYCLONE_10_100_COMBO:  /* 3c905B-COMBO */
                sc->xl_media = XL_MEDIAOPT_BTX|XL_MEDIAOPT_BNC|XL_MEDIAOPT_AUI;
                sc->xl_xcvr = XL_XCVR_AUTO;
                if (verbose)
                        if_printf(ifp, "guessing 10/100 plus BNC/AUI\n");
                break;
        default:
                if_printf(ifp,
                    "unknown device ID: %x -- defaulting to 10baseT\n", devid);
                sc->xl_media = XL_MEDIAOPT_BT;
                break;
        }

        return;
}

/*
 * Attach the interface. Allocate softc structures, do ifmedia
 * setup and ethernet/BPF attach.
 */
static int
xl_attach(device_t dev)
{
        u_char                  eaddr[ETHER_ADDR_LEN];
        u_int16_t               xcvr[2];
        struct xl_softc         *sc;
        struct ifnet            *ifp;
        int                     media = IFM_ETHER|IFM_100_TX|IFM_FDX;
        int                     error = 0, rid, res;
        uint16_t                did;

        sc = device_get_softc(dev);

        ifmedia_init(&sc->ifmedia, 0, xl_ifmedia_upd, xl_ifmedia_sts);

        did = pci_get_device(dev);

        sc->xl_flags = 0;
        if (did == TC_DEVICEID_HURRICANE_555)
                sc->xl_flags |= XL_FLAG_EEPROM_OFFSET_30 | XL_FLAG_PHYOK;
        if (did == TC_DEVICEID_HURRICANE_556 ||
            did == TC_DEVICEID_HURRICANE_556B)
                sc->xl_flags |= XL_FLAG_FUNCREG | XL_FLAG_PHYOK |
                    XL_FLAG_EEPROM_OFFSET_30 | XL_FLAG_WEIRDRESET |
                    XL_FLAG_INVERT_LED_PWR | XL_FLAG_INVERT_MII_PWR;
        if (did == TC_DEVICEID_HURRICANE_555 ||
            did == TC_DEVICEID_HURRICANE_556)
                sc->xl_flags |= XL_FLAG_8BITROM;
        if (did == TC_DEVICEID_HURRICANE_556B)
                sc->xl_flags |= XL_FLAG_NO_XCVR_PWR;
        if (did == TC_DEVICEID_HURRICANE_575B ||
            did == TC_DEVICEID_HURRICANE_575C ||
            did == TC_DEVICEID_HURRICANE_656B ||
            did == TC_DEVICEID_TORNADO_656C)
                sc->xl_flags |= XL_FLAG_FUNCREG;
        if (did == TC_DEVICEID_HURRICANE_575A ||
            did == TC_DEVICEID_HURRICANE_575B ||
            did == TC_DEVICEID_HURRICANE_575C ||
            did == TC_DEVICEID_HURRICANE_656B ||
            did == TC_DEVICEID_TORNADO_656C)
                sc->xl_flags |= XL_FLAG_PHYOK | XL_FLAG_EEPROM_OFFSET_30 |
                    XL_FLAG_8BITROM;
        if (did == TC_DEVICEID_HURRICANE_656)
                sc->xl_flags |= XL_FLAG_FUNCREG | XL_FLAG_PHYOK;
        if (did == TC_DEVICEID_HURRICANE_575B)
                sc->xl_flags |= XL_FLAG_INVERT_LED_PWR;
        if (did == TC_DEVICEID_HURRICANE_575C)
                sc->xl_flags |= XL_FLAG_INVERT_MII_PWR;
        if (did == TC_DEVICEID_TORNADO_656C)
                sc->xl_flags |= XL_FLAG_INVERT_MII_PWR;
        if (did == TC_DEVICEID_HURRICANE_656 ||
            did == TC_DEVICEID_HURRICANE_656B)
                sc->xl_flags |= XL_FLAG_INVERT_MII_PWR |
                    XL_FLAG_INVERT_LED_PWR;
        if (did == TC_DEVICEID_TORNADO_10_100BT_920B)
                sc->xl_flags |= XL_FLAG_PHYOK;
#ifndef BURN_BRIDGES
        /*
         * If this is a 3c905B, we have to check one extra thing.
         * The 905B supports power management and may be placed in
         * a low-power mode (D3 mode), typically by certain operating
         * systems which shall not be named. The PCI BIOS is supposed
         * to reset the NIC and bring it out of low-power mode, but
         * some do not. Consequently, we have to see if this chip
         * supports power management, and if so, make sure it's not
         * in low-power mode. If power management is available, the
         * capid byte will be 0x01.
         *
         * I _think_ that what actually happens is that the chip
         * loses its PCI configuration during the transition from
         * D3 back to D0; this means that it should be possible for
         * us to save the PCI iobase, membase and IRQ, put the chip
         * back in the D0 state, then restore the PCI config ourselves.
         */

        if (pci_get_powerstate(dev) != PCI_POWERSTATE_D0) {
                u_int32_t               iobase, membase, irq;

                /* Save important PCI config data. */
                iobase = pci_read_config(dev, XL_PCI_LOIO, 4);
                membase = pci_read_config(dev, XL_PCI_LOMEM, 4);
                irq = pci_read_config(dev, XL_PCI_INTLINE, 4);

                /* Reset the power state. */
                device_printf(dev, "chip is in D%d power mode "
                    "-- setting to D0\n", pci_get_powerstate(dev));

                pci_set_powerstate(dev, PCI_POWERSTATE_D0);

                /* Restore PCI config data. */
                pci_write_config(dev, XL_PCI_LOIO, iobase, 4);
                pci_write_config(dev, XL_PCI_LOMEM, membase, 4);
                pci_write_config(dev, XL_PCI_INTLINE, irq, 4);
        }
#endif
        /*
         * Map control/status registers.
         */
        pci_enable_busmaster(dev);

        rid = XL_PCI_LOMEM;
        res = SYS_RES_MEMORY;

#if 0
        sc->xl_res = bus_alloc_resource_any(dev, res, &rid, RF_ACTIVE);
#endif

        if (sc->xl_res != NULL) {
                sc->xl_flags |= XL_FLAG_USE_MMIO;
                if (bootverbose)
                        device_printf(dev, "using memory mapped I/O\n");
        } else {
                rid = XL_PCI_LOIO;
                res = SYS_RES_IOPORT;
                sc->xl_res = bus_alloc_resource_any(dev, res, &rid, RF_ACTIVE);
                if (sc->xl_res == NULL) {
                        device_printf(dev, "couldn't map ports/memory\n");
                        error = ENXIO;
                        goto fail;
                }
                if (bootverbose)
                        device_printf(dev, "using port I/O\n");
        }

        sc->xl_btag = rman_get_bustag(sc->xl_res);
        sc->xl_bhandle = rman_get_bushandle(sc->xl_res);

        if (sc->xl_flags & XL_FLAG_FUNCREG) {
                rid = XL_PCI_FUNCMEM;
                sc->xl_fres = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
                    RF_ACTIVE);

                if (sc->xl_fres == NULL) {
                        device_printf(dev, "couldn't map funcreg memory\n");
                        error = ENXIO;
                        goto fail;
                }

                sc->xl_ftag = rman_get_bustag(sc->xl_fres);
                sc->xl_fhandle = rman_get_bushandle(sc->xl_fres);
        }

        /* Allocate interrupt */
        rid = 0;
        sc->xl_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
            RF_SHAREABLE | RF_ACTIVE);
        if (sc->xl_irq == NULL) {
                device_printf(dev, "couldn't map interrupt\n");
                error = ENXIO;
                goto fail;
        }

        ifp = &sc->arpcom.ac_if;
        if_initname(ifp, device_get_name(dev), device_get_unit(dev));

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

        /*
         * Get station address from the EEPROM.
         */
        if (xl_read_eeprom(sc, (caddr_t)&eaddr, XL_EE_OEM_ADR0, 3, 1)) {
                device_printf(dev, "failed to read station address\n");
                error = ENXIO;
                goto fail;
        }

        callout_init(&sc->xl_stat_timer);

        error = xl_dma_alloc(dev);
        if (error)
                goto fail;

        /*
         * Figure out the card type. 3c905B adapters have the
         * 'supportsNoTxLength' bit set in the capabilities
         * word in the EEPROM.
         * Note: my 3c575C cardbus card lies. It returns a value
         * of 0x1578 for its capabilities word, which is somewhat
         * nonsensical. Another way to distinguish a 3c90x chip
         * from a 3c90xB/C chip is to check for the 'supportsLargePackets'
         * bit. This will only be set for 3c90x boomerage chips.
         */
        xl_read_eeprom(sc, (caddr_t)&sc->xl_caps, XL_EE_CAPS, 1, 0);
        if (sc->xl_caps & XL_CAPS_NO_TXLENGTH ||
            !(sc->xl_caps & XL_CAPS_LARGE_PKTS))
                sc->xl_type = XL_TYPE_905B;
        else
                sc->xl_type = XL_TYPE_90X;
        if (bootverbose) {
                device_printf(dev, "type %s\n",
                              sc->xl_type == XL_TYPE_905B ? "90XB" : "90X");
        }

        ifp->if_softc = sc;
        ifp->if_mtu = ETHERMTU;
        ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
        ifp->if_ioctl = xl_ioctl;
        if (sc->xl_type == XL_TYPE_905B) {
                ifp->if_start = xl_start_90xB;
                ifp->if_capabilities |= IFCAP_HWCSUM | IFCAP_VLAN_MTU;
        } else {
                ifp->if_start = xl_start;
        }
        ifp->if_watchdog = xl_watchdog;
        ifp->if_init = xl_init;
#ifdef DEVICE_POLLING
        ifp->if_poll = xl_poll;
#endif
        ifp->if_baudrate = 10000000;
        ifq_set_maxlen(&ifp->if_snd, XL_TX_LIST_CNT - 1);
        ifq_set_ready(&ifp->if_snd);
        /*
         * NOTE: Hardware checksum features disabled by default.
         * This seems to corrupt tx packet data one out of a
         * million packets or so and then generates a good checksum
         * so the receiver doesn't know the packet is bad 
         */
        ifp->if_capenable = ifp->if_capabilities & ~IFCAP_HWCSUM;
        if (ifp->if_capenable & IFCAP_TXCSUM)
                ifp->if_hwassist = XL905B_CSUM_FEATURES;

        /*
         * Now we have to see what sort of media we have.
         * This includes probing for an MII interace and a
         * possible PHY.
         */
        XL_SEL_WIN(3);
        sc->xl_media = CSR_READ_2(sc, XL_W3_MEDIA_OPT);
        if (bootverbose)
                if_printf(ifp, "media options word: %x\n", sc->xl_media);

        xl_read_eeprom(sc, (char *)&xcvr, XL_EE_ICFG_0, 2, 0);
        sc->xl_xcvr = xcvr[0] | xcvr[1] << 16;
        sc->xl_xcvr &= XL_ICFG_CONNECTOR_MASK;
        sc->xl_xcvr >>= XL_ICFG_CONNECTOR_BITS;

        xl_mediacheck(sc);

        if (sc->xl_media & XL_MEDIAOPT_MII || sc->xl_media & XL_MEDIAOPT_BTX
                        || sc->xl_media & XL_MEDIAOPT_BT4) {
                if (bootverbose)
                        if_printf(ifp, "found MII/AUTO\n");
                xl_setcfg(sc);

                error = mii_phy_probe(dev, &sc->xl_miibus,
                                      xl_ifmedia_upd, xl_ifmedia_sts);
                if (error) {
                        if_printf(ifp, "no PHY found!\n");
                        goto fail;
                }

                goto done;
        }

        /*
         * Sanity check. If the user has selected "auto" and this isn't
         * a 10/100 card of some kind, we need to force the transceiver
         * type to something sane.
         */
        if (sc->xl_xcvr == XL_XCVR_AUTO)
                xl_choose_xcvr(sc, bootverbose);

        /*
         * Do ifmedia setup.
         */
        if (sc->xl_media & XL_MEDIAOPT_BT) {
                if (bootverbose)
                        if_printf(ifp, "found 10baseT\n");
                ifmedia_add(&sc->ifmedia, IFM_ETHER|IFM_10_T, 0, NULL);
                ifmedia_add(&sc->ifmedia, IFM_ETHER|IFM_10_T|IFM_HDX, 0, NULL);
                if (sc->xl_caps & XL_CAPS_FULL_DUPLEX)
                        ifmedia_add(&sc->ifmedia,
                            IFM_ETHER|IFM_10_T|IFM_FDX, 0, NULL);
        }

        if (sc->xl_media & (XL_MEDIAOPT_AUI|XL_MEDIAOPT_10FL)) {
                /*
                 * Check for a 10baseFL board in disguise.
                 */
                if (sc->xl_type == XL_TYPE_905B &&
                    sc->xl_media == XL_MEDIAOPT_10FL) {
                        if (bootverbose)
                                if_printf(ifp, "found 10baseFL\n");
                        ifmedia_add(&sc->ifmedia, IFM_ETHER|IFM_10_FL, 0, NULL);
                        ifmedia_add(&sc->ifmedia, IFM_ETHER|IFM_10_FL|IFM_HDX,
                            0, NULL);
                        if (sc->xl_caps & XL_CAPS_FULL_DUPLEX)
                                ifmedia_add(&sc->ifmedia,
                                    IFM_ETHER|IFM_10_FL|IFM_FDX, 0, NULL);
                } else {
                        if (bootverbose)
                                if_printf(ifp, "found AUI\n");
                        ifmedia_add(&sc->ifmedia, IFM_ETHER|IFM_10_5, 0, NULL);
                }
        }

        if (sc->xl_media & XL_MEDIAOPT_BNC) {
                if (bootverbose)
                        if_printf(ifp, "found BNC\n");
                ifmedia_add(&sc->ifmedia, IFM_ETHER|IFM_10_2, 0, NULL);
        }

        if (sc->xl_media & XL_MEDIAOPT_BFX) {
                if (bootverbose)
                        if_printf(ifp, "found 100baseFX\n");
                ifp->if_baudrate = 100000000;
                ifmedia_add(&sc->ifmedia, IFM_ETHER|IFM_100_FX, 0, NULL);
        }

        /* Choose a default media. */
        switch(sc->xl_xcvr) {
        case XL_XCVR_10BT:
                media = IFM_ETHER|IFM_10_T;
                xl_setmode(sc, media);
                break;
        case XL_XCVR_AUI:
                if (sc->xl_type == XL_TYPE_905B &&
                    sc->xl_media == XL_MEDIAOPT_10FL) {
                        media = IFM_ETHER|IFM_10_FL;
                        xl_setmode(sc, media);
                } else {
                        media = IFM_ETHER|IFM_10_5;
                        xl_setmode(sc, media);
                }
                break;
        case XL_XCVR_COAX:
                media = IFM_ETHER|IFM_10_2;
                xl_setmode(sc, media);
                break;
        case XL_XCVR_AUTO:
        case XL_XCVR_100BTX:
        case XL_XCVR_MII:
                /* Chosen by miibus */
                break;
        case XL_XCVR_100BFX:
                media = IFM_ETHER|IFM_100_FX;
                break;
        default:
                if_printf(ifp, "unknown XCVR type: %d\n", sc->xl_xcvr);
                /*
                 * This will probably be wrong, but it prevents
                 * the ifmedia code from panicking.
                 */
                media = IFM_ETHER|IFM_10_T;
                break;
        }

        if (sc->xl_miibus == NULL)
                ifmedia_set(&sc->ifmedia, media);

done:

        if (sc->xl_flags & XL_FLAG_NO_XCVR_PWR) {
                XL_SEL_WIN(0);
                CSR_WRITE_2(sc, XL_W0_MFG_ID, XL_NO_XCVR_PWR_MAGICBITS);
        }

        /*
         * Call MI attach routine.
         */
        ether_ifattach(ifp, eaddr, NULL);

        /*
         * Tell the upper layer(s) we support long frames.
         */
        ifp->if_data.ifi_hdrlen = sizeof(struct ether_vlan_header);

        /* Hook interrupt last to avoid having to lock softc */
        error = bus_setup_intr(dev, sc->xl_irq, INTR_MPSAFE,
                               xl_intr, sc, &sc->xl_intrhand, 
                               ifp->if_serializer);
        if (error) {
                if_printf(ifp, "couldn't set up irq\n");
                ether_ifdetach(ifp);
                goto fail;
        }

        ifp->if_cpuid = ithread_cpuid(rman_get_start(sc->xl_irq));
        KKASSERT(ifp->if_cpuid >= 0 && ifp->if_cpuid < ncpus);

        return 0;

fail:
        xl_detach(dev);
        return error;
}

/*
 * Shutdown hardware and free up resources. This can be called any
 * time after the mutex has been initialized. It is called in both
 * the error case in attach and the normal detach case so it needs
 * to be careful about only freeing resources that have actually been
 * allocated.
 */
static int
xl_detach(device_t dev)
{
        struct xl_softc         *sc;
        struct ifnet            *ifp;
        int                     rid, res;

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

        if (sc->xl_flags & XL_FLAG_USE_MMIO) {
                rid = XL_PCI_LOMEM;
                res = SYS_RES_MEMORY;
        } else {
                rid = XL_PCI_LOIO;   
                res = SYS_RES_IOPORT;
        }

        if (device_is_attached(dev)) {
                lwkt_serialize_enter(ifp->if_serializer);
                xl_reset(sc);
                xl_stop(sc);
                bus_teardown_intr(dev, sc->xl_irq, sc->xl_intrhand);
                lwkt_serialize_exit(ifp->if_serializer);

                ether_ifdetach(ifp);
        }

        if (sc->xl_miibus)
                device_delete_child(dev, sc->xl_miibus);
        bus_generic_detach(dev);
        ifmedia_removeall(&sc->ifmedia);

        if (sc->xl_irq)
                bus_release_resource(dev, SYS_RES_IRQ, 0, sc->xl_irq);
        if (sc->xl_fres != NULL)
                bus_release_resource(dev, SYS_RES_MEMORY,
                    XL_PCI_FUNCMEM, sc->xl_fres);
        if (sc->xl_res)
                bus_release_resource(dev, res, rid, sc->xl_res);

        xl_dma_free(dev);

        return(0);
}

static int
xl_dma_alloc(device_t dev)
{
        struct xl_softc *sc;
        struct xl_chain_data *cd;
        struct xl_list_data *ld;
        bus_dmamem_t dmem;
        int i, error;

        sc = device_get_softc(dev);
        cd = &sc->xl_cdata;
        ld = &sc->xl_ldata;

        /*
         * Allocate the parent bus DMA tag appropriate for PCI.
         */
        error = bus_dma_tag_create(NULL, 1, 0,
                                   BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR,
                                   NULL, NULL,
                                   BUS_SPACE_MAXSIZE_32BIT, 0,
                                   BUS_SPACE_MAXSIZE_32BIT,
                                   0, &sc->xl_parent_tag);
        if (error) {
                device_printf(dev, "could not allocate parent dma tag\n");
                return error;
        }

        /*
         * Now allocate a tag for the DMA descriptor lists and a chunk
         * of DMA-able memory based on the tag.  Also obtain the DMA
         * addresses of the RX and TX ring, which we'll need later.
         * All of our lists are allocated as a contiguous block
         * of memory.
         */
        error = bus_dmamem_coherent(sc->xl_parent_tag, XL_LIST_ALIGN, 0,
                                    BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
                                    XL_RX_LIST_SZ, BUS_DMA_WAITOK, &dmem);
        if (error) {
                device_printf(dev, "failed to allocate rx list\n");
                return error;
        }
        ld->xl_rx_tag = dmem.dmem_tag;
        ld->xl_rx_dmamap = dmem.dmem_map;
        ld->xl_rx_list = dmem.dmem_addr;
        ld->xl_rx_dmaaddr = dmem.dmem_busaddr;

        error = bus_dmamem_coherent(sc->xl_parent_tag, XL_LIST_ALIGN, 0,
                                    BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
                                    XL_TX_LIST_SZ, BUS_DMA_WAITOK, &dmem);
        if (error) {
                device_printf(dev, "failed to allocate tx list\n");
                return error;
        }
        ld->xl_tx_tag = dmem.dmem_tag;
        ld->xl_tx_dmamap = dmem.dmem_map;
        ld->xl_tx_list = dmem.dmem_addr;
        ld->xl_tx_dmaaddr = dmem.dmem_busaddr;

        /*
         * Allocate a DMA tag for the mapping of mbufs.
         */
        error = bus_dma_tag_create(sc->xl_parent_tag, 1, 0,
                                   BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
                                   NULL, NULL,
                                   MCLBYTES, 1, MCLBYTES,
                                   BUS_DMA_WAITOK | BUS_DMA_ALLOCNOW,
                                   &sc->xl_rx_mtag);
        if (error) {
                device_printf(dev, "failed to allocate RX mbuf dma tag\n");
                return error;
        }

        /*
         * Allocate a spare DMA map for the RX ring.
         */
        error = bus_dmamap_create(sc->xl_rx_mtag, BUS_DMA_WAITOK,
                                  &sc->xl_tmpmap);
        if (error) {
                device_printf(dev, "failed to create RX mbuf tmp dma map\n");
                bus_dma_tag_destroy(sc->xl_rx_mtag);
                sc->xl_rx_mtag = NULL;
                return error;
        }

        for (i = 0; i < XL_RX_LIST_CNT; i++) {
                error = bus_dmamap_create(sc->xl_rx_mtag, BUS_DMA_WAITOK,
                                          &cd->xl_rx_chain[i].xl_map);
                if (error) {
                        device_printf(dev, "failed to create %dth "
                                      "rx descriptor dma map!\n", i);
                        return error;
                }
                cd->xl_rx_chain[i].xl_ptr = &ld->xl_rx_list[i];
        }

        error = bus_dma_tag_create(sc->xl_parent_tag, 1, 0,
                                   BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
                                   NULL, NULL,
                                   MCLBYTES, XL_MAXFRAGS, MCLBYTES,
                                   BUS_DMA_ALLOCNOW | BUS_DMA_WAITOK,
                                   &sc->xl_tx_mtag);
        if (error) {
                device_printf(dev, "failed to allocate TX mbuf dma tag\n");
                return error;
        }

        for (i = 0; i < XL_TX_LIST_CNT; i++) {
                error = bus_dmamap_create(sc->xl_tx_mtag, BUS_DMA_WAITOK,
                                          &cd->xl_tx_chain[i].xl_map);
                if (error) {
                        device_printf(dev, "failed to create %dth "
                                      "tx descriptor dma map!\n", i);
                        return error;
                }
                cd->xl_tx_chain[i].xl_ptr = &ld->xl_tx_list[i];
        }
        return 0;
}

static void
xl_dma_free(device_t dev)
{
        struct xl_softc *sc;
        struct xl_chain_data *cd;
        struct xl_list_data *ld;
        int i;

        sc = device_get_softc(dev);
        cd = &sc->xl_cdata;
        ld = &sc->xl_ldata;

        for (i = 0; i < XL_RX_LIST_CNT; ++i) {
                if (cd->xl_rx_chain[i].xl_ptr != NULL) {
                        if (cd->xl_rx_chain[i].xl_mbuf != NULL) {
                                bus_dmamap_unload(sc->xl_rx_mtag,
                                                  cd->xl_rx_chain[i].xl_map);
                                m_freem(cd->xl_rx_chain[i].xl_mbuf);
                        }
                        bus_dmamap_destroy(sc->xl_rx_mtag,
                                           cd->xl_rx_chain[i].xl_map);
                }
        }

        for (i = 0; i < XL_TX_LIST_CNT; ++i) {
                if (cd->xl_tx_chain[i].xl_ptr != NULL) {
                        if (cd->xl_tx_chain[i].xl_mbuf != NULL) {
                                bus_dmamap_unload(sc->xl_tx_mtag,
                                                  cd->xl_tx_chain[i].xl_map);
                                m_freem(cd->xl_tx_chain[i].xl_mbuf);
                        }
                        bus_dmamap_destroy(sc->xl_tx_mtag,
                                           cd->xl_tx_chain[i].xl_map);
                }
        }

        if (ld->xl_rx_tag) {
                bus_dmamap_unload(ld->xl_rx_tag, ld->xl_rx_dmamap);
                bus_dmamem_free(ld->xl_rx_tag, ld->xl_rx_list,
                                ld->xl_rx_dmamap);
                bus_dma_tag_destroy(ld->xl_rx_tag);
        }

        if (ld->xl_tx_tag) {
                bus_dmamap_unload(ld->xl_tx_tag, ld->xl_tx_dmamap);
                bus_dmamem_free(ld->xl_tx_tag, ld->xl_tx_list,
                                ld->xl_tx_dmamap);
                bus_dma_tag_destroy(ld->xl_tx_tag);
        }

        if (sc->xl_rx_mtag) {
                bus_dmamap_destroy(sc->xl_rx_mtag, sc->xl_tmpmap);
                bus_dma_tag_destroy(sc->xl_rx_mtag);
        }
        if (sc->xl_tx_mtag)
                bus_dma_tag_destroy(sc->xl_tx_mtag);

        if (sc->xl_parent_tag)
                bus_dma_tag_destroy(sc->xl_parent_tag);
}

/*
 * Initialize the transmit descriptors.
 */
static void
xl_list_tx_init(struct xl_softc *sc)
{
        struct xl_chain_data    *cd;
        struct xl_list_data     *ld;
        int                     i;

        cd = &sc->xl_cdata;
        ld = &sc->xl_ldata;
        for (i = 0; i < XL_TX_LIST_CNT; i++) {
                cd->xl_tx_chain[i].xl_phys = ld->xl_tx_dmaaddr +
                    i * sizeof(struct xl_list);
                if (i == (XL_TX_LIST_CNT - 1))
                        cd->xl_tx_chain[i].xl_next = NULL;
                else
                        cd->xl_tx_chain[i].xl_next = &cd->xl_tx_chain[i + 1];
        }

        cd->xl_tx_free = &cd->xl_tx_chain[0];
        cd->xl_tx_tail = cd->xl_tx_head = NULL;
}

/*
 * Initialize the transmit descriptors.
 */
static void
xl_list_tx_init_90xB(struct xl_softc *sc)
{
        struct xl_chain_data    *cd;
        struct xl_list_data     *ld;
        int                     i;

        cd = &sc->xl_cdata;
        ld = &sc->xl_ldata;
        for (i = 0; i < XL_TX_LIST_CNT; i++) {
                cd->xl_tx_chain[i].xl_phys = ld->xl_tx_dmaaddr +
                    i * sizeof(struct xl_list);
                if (i == (XL_TX_LIST_CNT - 1))
                        cd->xl_tx_chain[i].xl_next = &cd->xl_tx_chain[0];
                else
                        cd->xl_tx_chain[i].xl_next = &cd->xl_tx_chain[i + 1];
                if (i == 0) {
                        cd->xl_tx_chain[i].xl_prev =
                            &cd->xl_tx_chain[XL_TX_LIST_CNT - 1];
                } else {
                        cd->xl_tx_chain[i].xl_prev =
                            &cd->xl_tx_chain[i - 1];
                }
        }

        ld->xl_tx_list[0].xl_status = htole32(XL_TXSTAT_EMPTY);

        cd->xl_tx_prod = 1;
        cd->xl_tx_cons = 1;
        cd->xl_tx_cnt = 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
xl_list_rx_init(struct xl_softc *sc)
{
        struct xl_chain_data    *cd;
        struct xl_list_data     *ld;
        int                     error, i, next;
        u_int32_t               nextptr;

        cd = &sc->xl_cdata;
        ld = &sc->xl_ldata;

        for (i = 0; i < XL_RX_LIST_CNT; i++) {
                error = xl_newbuf(sc, &cd->xl_rx_chain[i], 1);
                if (error)
                        return(error);
                if (i == (XL_RX_LIST_CNT - 1))
                        next = 0;
                else
                        next = i + 1;
                nextptr = ld->xl_rx_dmaaddr +
                    next * sizeof(struct xl_list_onefrag);
                cd->xl_rx_chain[i].xl_next = &cd->xl_rx_chain[next];
                ld->xl_rx_list[i].xl_next = htole32(nextptr);
        }

        cd->xl_rx_head = &cd->xl_rx_chain[0];

        return(0);
}

/*
 * Initialize an RX descriptor and attach an MBUF cluster.
 * If we fail to do so, we need to leave the old mbuf and
 * the old DMA map untouched so that it can be reused.
 */
static int
xl_newbuf(struct xl_softc *sc, struct xl_chain_onefrag *c, int init)
{
        struct mbuf             *m_new;
        bus_dmamap_t            map;
        int                     error, nsegs;
        bus_dma_segment_t       seg;

        m_new = m_getcl(init ? MB_WAIT : MB_DONTWAIT, MT_DATA, M_PKTHDR);
        if (m_new == NULL)
                return(ENOBUFS);

        m_new->m_len = m_new->m_pkthdr.len = MCLBYTES;

        /* Force longword alignment for packet payload. */
        m_adj(m_new, ETHER_ALIGN);

        error = bus_dmamap_load_mbuf_segment(sc->xl_rx_mtag, sc->xl_tmpmap,
                        m_new, &seg, 1, &nsegs, BUS_DMA_NOWAIT);
        if (error) {
                m_freem(m_new);
                if (init) {
                        if_printf(&sc->arpcom.ac_if,
                                  "can't map mbuf (error %d)\n", error);
                }
                return(error);
        }

        if (c->xl_mbuf != NULL) {
                bus_dmamap_sync(sc->xl_rx_mtag, c->xl_map,
                                BUS_DMASYNC_POSTREAD);
                bus_dmamap_unload(sc->xl_rx_mtag, c->xl_map);
        }

        map = c->xl_map;
        c->xl_map = sc->xl_tmpmap;
        sc->xl_tmpmap = map;
        c->xl_mbuf = m_new;

        c->xl_ptr->xl_frag.xl_len = htole32(seg.ds_len | XL_LAST_FRAG);
        c->xl_ptr->xl_frag.xl_addr = htole32(seg.ds_addr);
        c->xl_ptr->xl_status = 0;

        return(0);
}

static int
xl_rx_resync(struct xl_softc *sc)
{
        struct xl_chain_onefrag *pos;
        int                     i;

        pos = sc->xl_cdata.xl_rx_head;

        for (i = 0; i < XL_RX_LIST_CNT; i++) {
                if (pos->xl_ptr->xl_status)
                        break;
                pos = pos->xl_next;
        }

        if (i == XL_RX_LIST_CNT)
                return(0);

        sc->xl_cdata.xl_rx_head = pos;

        return(EAGAIN);
}

/*
 * A frame has been uploaded: pass the resulting mbuf chain up to
 * the higher level protocols.
 */
static void
xl_rxeof(struct xl_softc *sc, int count)
{
        struct mbuf             *m;
        struct ifnet            *ifp;
        struct xl_chain_onefrag *cur_rx;
        int                     total_len = 0;
        u_int32_t               rxstat;
        struct mbuf_chain chain[MAXCPU];

        ifp = &sc->arpcom.ac_if;

        ether_input_chain_init(chain);
again:
        while((rxstat = le32toh(sc->xl_cdata.xl_rx_head->xl_ptr->xl_status))) {
#ifdef DEVICE_POLLING
                if (count >= 0 && count-- == 0)
                        break;
#endif
                cur_rx = sc->xl_cdata.xl_rx_head;
                sc->xl_cdata.xl_rx_head = cur_rx->xl_next;
                total_len = rxstat & XL_RXSTAT_LENMASK;

                /*
                 * Since we have told the chip to allow large frames,
                 * we need to trap giant frame errors in software. We allow
                 * a little more than the normal frame size to account for
                 * frames with VLAN tags.
                 */
                if (total_len > XL_MAX_FRAMELEN)
                        rxstat |= (XL_RXSTAT_UP_ERROR|XL_RXSTAT_OVERSIZE);

                /*
                 * 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 & XL_RXSTAT_UP_ERROR) {
                        ifp->if_ierrors++;
                        cur_rx->xl_ptr->xl_status = 0;
                        continue;
                }

                /*
                 * If the error bit was not set, the upload complete
                 * bit should be set which means we have a valid packet.
                 * If not, something truly strange has happened.
                 */
                if (!(rxstat & XL_RXSTAT_UP_CMPLT)) {
                        if_printf(ifp,
                                  "bad receive status -- packet dropped\n");
                        ifp->if_ierrors++;
                        cur_rx->xl_ptr->xl_status = 0;
                        continue;
                }

                /* No errors; receive the packet. */    
                m = cur_rx->xl_mbuf;

                /*
                 * Try to conjure up a new mbuf cluster. If that
                 * fails, it means we have an out of memory condition and
                 * should leave the buffer in place and continue. This will
                 * result in a lost packet, but there's little else we
                 * can do in this situation.
                 */
                if (xl_newbuf(sc, cur_rx, 0)) {
                        ifp->if_ierrors++;
                        cur_rx->xl_ptr->xl_status = 0;
                        continue;
                }

                ifp->if_ipackets++;
                m->m_pkthdr.rcvif = ifp;
                m->m_pkthdr.len = m->m_len = total_len;

                if (ifp->if_capenable & IFCAP_RXCSUM) {
                        /* Do IP checksum checking. */
                        if (rxstat & XL_RXSTAT_IPCKOK)
                                m->m_pkthdr.csum_flags |= CSUM_IP_CHECKED;
                        if (!(rxstat & XL_RXSTAT_IPCKERR))
                                m->m_pkthdr.csum_flags |= CSUM_IP_VALID;
                        if ((rxstat & XL_RXSTAT_TCPCOK &&
                             !(rxstat & XL_RXSTAT_TCPCKERR)) ||
                            (rxstat & XL_RXSTAT_UDPCKOK &&
                             !(rxstat & XL_RXSTAT_UDPCKERR))) {
                                m->m_pkthdr.csum_flags |=
                                        CSUM_DATA_VALID|CSUM_PSEUDO_HDR|
                                        CSUM_FRAG_NOT_CHECKED;
                                m->m_pkthdr.csum_data = 0xffff;
                        }
                }

                ether_input_chain(ifp, m, NULL, chain);
        }

        if (sc->xl_type != XL_TYPE_905B) {
                /*
                 * Handle the 'end of channel' condition. When the upload
                 * engine hits the end of the RX ring, it will stall. This
                 * is our cue to flush the RX ring, reload the uplist pointer
                 * register and unstall the engine.
                 * XXX This is actually a little goofy. With the ThunderLAN
                 * chip, you get an interrupt when the receiver hits the end
                 * of the receive ring, which tells you exactly when you
                 * you need to reload the ring pointer. Here we have to
                 * fake it. I'm mad at myself for not being clever enough
                 * to avoid the use of a goto here.
                 */
                if (CSR_READ_4(sc, XL_UPLIST_PTR) == 0 ||
                    CSR_READ_4(sc, XL_UPLIST_STATUS) & XL_PKTSTAT_UP_STALLED) {
                        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_UP_STALL);
                        xl_wait(sc);
                        CSR_WRITE_4(sc, XL_UPLIST_PTR,
                                    sc->xl_ldata.xl_rx_dmaaddr);
                        sc->xl_cdata.xl_rx_head = &sc->xl_cdata.xl_rx_chain[0];
                        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_UP_UNSTALL);
                        goto again;
                }
        }

        ether_input_dispatch(chain);
}

/*
 * A frame was downloaded to the chip. It's safe for us to clean up
 * the list buffers.
 */
static void
xl_txeof(struct xl_softc *sc)
{
        struct xl_chain         *cur_tx;
        struct ifnet            *ifp;

        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 uploaded. Note: the 3c905B
         * sets a special bit in the status word to let us
         * know that a frame has been downloaded, but the
         * original 3c900/3c905 adapters don't do that.
         * Consequently, we have to use a different test if
         * xl_type != XL_TYPE_905B.
         */
        while(sc->xl_cdata.xl_tx_head != NULL) {
                cur_tx = sc->xl_cdata.xl_tx_head;

                if (CSR_READ_4(sc, XL_DOWNLIST_PTR))
                        break;

                sc->xl_cdata.xl_tx_head = cur_tx->xl_next;
                bus_dmamap_unload(sc->xl_tx_mtag, cur_tx->xl_map);
                m_freem(cur_tx->xl_mbuf);
                cur_tx->xl_mbuf = NULL;
                ifp->if_opackets++;

                cur_tx->xl_next = sc->xl_cdata.xl_tx_free;
                sc->xl_cdata.xl_tx_free = cur_tx;
        }

        if (sc->xl_cdata.xl_tx_head == NULL) {
                ifp->if_flags &= ~IFF_OACTIVE;
                sc->xl_cdata.xl_tx_tail = NULL;
        } else {
                if (CSR_READ_4(sc, XL_DMACTL) & XL_DMACTL_DOWN_STALLED ||
                        !CSR_READ_4(sc, XL_DOWNLIST_PTR)) {
                        CSR_WRITE_4(sc, XL_DOWNLIST_PTR,
                                sc->xl_cdata.xl_tx_head->xl_phys);
                        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_DOWN_UNSTALL);
                }
        }

        return;
}

static void
xl_txeof_90xB(struct xl_softc *sc)
{
        struct xl_chain         *cur_tx = NULL;
        struct ifnet            *ifp;
        int                     idx;

        ifp = &sc->arpcom.ac_if;

        idx = sc->xl_cdata.xl_tx_cons;
        while(idx != sc->xl_cdata.xl_tx_prod) {

                cur_tx = &sc->xl_cdata.xl_tx_chain[idx];

                if (!(le32toh(cur_tx->xl_ptr->xl_status) &
                      XL_TXSTAT_DL_COMPLETE))
                        break;

                if (cur_tx->xl_mbuf != NULL) {
                        bus_dmamap_unload(sc->xl_tx_mtag, cur_tx->xl_map);
                        m_freem(cur_tx->xl_mbuf);
                        cur_tx->xl_mbuf = NULL;
                }

                ifp->if_opackets++;

                sc->xl_cdata.xl_tx_cnt--;
                XL_INC(idx, XL_TX_LIST_CNT);
                ifp->if_timer = 0;
        }

        sc->xl_cdata.xl_tx_cons = idx;

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

        return;
}

/*
 * TX 'end of channel' interrupt handler. Actually, we should
 * only get a 'TX complete' interrupt if there's a transmit error,
 * so this is really TX error handler.
 */
static void
xl_txeoc(struct xl_softc *sc)
{
        struct ifnet *ifp = &sc->arpcom.ac_if;
        u_int8_t                txstat;

        while((txstat = CSR_READ_1(sc, XL_TX_STATUS))) {
                if (txstat & XL_TXSTATUS_UNDERRUN ||
                        txstat & XL_TXSTATUS_JABBER ||
                        txstat & XL_TXSTATUS_RECLAIM) {
                        if_printf(ifp, "transmission error: %x\n", txstat);
                        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_RESET);
                        xl_wait(sc);
                        if (sc->xl_type == XL_TYPE_905B) {
                                if (sc->xl_cdata.xl_tx_cnt) {
                                        int                     i;
                                        struct xl_chain         *c;
                                        i = sc->xl_cdata.xl_tx_cons;
                                        c = &sc->xl_cdata.xl_tx_chain[i];
                                        CSR_WRITE_4(sc, XL_DOWNLIST_PTR,
                                            c->xl_phys);
                                        CSR_WRITE_1(sc, XL_DOWN_POLL, 64);
                                }
                        } else {
                                if (sc->xl_cdata.xl_tx_head != NULL)
                                        CSR_WRITE_4(sc, XL_DOWNLIST_PTR,
                                            sc->xl_cdata.xl_tx_head->xl_phys);
                        }
                        /*
                         * Remember to set this for the
                         * first generation 3c90X chips.
                         */
                        CSR_WRITE_1(sc, XL_TX_FREETHRESH, XL_PACKET_SIZE >> 8);
                        if (txstat & XL_TXSTATUS_UNDERRUN &&
                            sc->xl_tx_thresh < XL_PACKET_SIZE) {
                                sc->xl_tx_thresh += XL_MIN_FRAMELEN;
                                if_printf(ifp, "tx underrun, increasing tx start"
                                    " threshold to %d bytes\n",
                                    sc->xl_tx_thresh);
                        }
                        CSR_WRITE_2(sc, XL_COMMAND,
                            XL_CMD_TX_SET_START|sc->xl_tx_thresh);
                        if (sc->xl_type == XL_TYPE_905B) {
                                CSR_WRITE_2(sc, XL_COMMAND,
                                XL_CMD_SET_TX_RECLAIM|(XL_PACKET_SIZE >> 4));
                        }
                        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_ENABLE);
                        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_DOWN_UNSTALL);
                } else {
                        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_ENABLE);
                        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_DOWN_UNSTALL);
                }
                /*
                 * Write an arbitrary byte to the TX_STATUS register
                 * to clear this interrupt/error and advance to the next.
                 */
                CSR_WRITE_1(sc, XL_TX_STATUS, 0x01);
        }

        return;
}

#ifdef DEVICE_POLLING

static void
xl_poll(struct ifnet *ifp, enum poll_cmd cmd, int count)
{
        struct xl_softc *sc = ifp->if_softc;

        ASSERT_SERIALIZED(ifp->if_serializer);

        switch (cmd) {
        case POLL_REGISTER:
                xl_enable_intrs(sc, 0);
                if (sc->xl_type != XL_TYPE_905B)
                        ifp->if_start = xl_start_poll;
                break;
        case POLL_DEREGISTER:
                if (sc->xl_type != XL_TYPE_905B)
                        ifp->if_start = xl_start;
                xl_enable_intrs(sc, XL_INTRS);
                break;
        case POLL_ONLY:
        case POLL_AND_CHECK_STATUS:
                xl_rxeof(sc, count);
                if (sc->xl_type == XL_TYPE_905B)
                        xl_txeof_90xB(sc);
                else
                        xl_txeof(sc);

                if (!ifq_is_empty(&ifp->if_snd))
                        if_devstart(ifp);

                if (cmd == POLL_AND_CHECK_STATUS) {
                        uint16_t status;

                        /* XXX copy & pasted from xl_intr() */
                        status = CSR_READ_2(sc, XL_STATUS);
                        if ((status & XL_INTRS) && status != 0xFFFF) {
                                CSR_WRITE_2(sc, XL_COMMAND,
                                    XL_CMD_INTR_ACK | (status & XL_INTRS));

                                if (status & XL_STAT_TX_COMPLETE) {
                                        ifp->if_oerrors++;
                                        xl_txeoc(sc);
                                }

                                if (status & XL_STAT_ADFAIL) {
                                        xl_reset(sc);
                                        xl_init(sc);
                                }

                                if (status & XL_STAT_STATSOFLOW) {
                                        sc->xl_stats_no_timeout = 1;
                                        xl_stats_update_serialized(sc);
                                        sc->xl_stats_no_timeout = 0;
                                }
                        }
                }
                break;
        }
}

#endif  /* DEVICE_POLLING */

static void
xl_intr(void *arg)
{
        struct xl_softc         *sc;
        struct ifnet            *ifp;
        u_int16_t               status;

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

        ASSERT_SERIALIZED(ifp->if_serializer);

        while(((status = CSR_READ_2(sc, XL_STATUS)) & XL_INTRS) &&
              status != 0xFFFF) {

                CSR_WRITE_2(sc, XL_COMMAND,
                    XL_CMD_INTR_ACK|(status & XL_INTRS));

                if (status & XL_STAT_UP_COMPLETE) {
                        int                     curpkts;

                        curpkts = ifp->if_ipackets;
                        xl_rxeof(sc, -1);
                        if (curpkts == ifp->if_ipackets) {
                                while (xl_rx_resync(sc))
                                        xl_rxeof(sc, -1);
                        }
                }

                if (status & XL_STAT_DOWN_COMPLETE) {
                        if (sc->xl_type == XL_TYPE_905B)
                                xl_txeof_90xB(sc);
                        else
                                xl_txeof(sc);
                }

                if (status & XL_STAT_TX_COMPLETE) {
                        ifp->if_oerrors++;
                        xl_txeoc(sc);
                }

                if (status & XL_STAT_ADFAIL) {
                        xl_reset(sc);
                        xl_init(sc);
                }

                if (status & XL_STAT_STATSOFLOW) {
                        sc->xl_stats_no_timeout = 1;
                        xl_stats_update_serialized(sc);
                        sc->xl_stats_no_timeout = 0;
                }
        }

        if (!ifq_is_empty(&ifp->if_snd))
                if_devstart(ifp);
}

static void
xl_stats_update(void *xsc)
{
        struct xl_softc *sc = xsc;

        lwkt_serialize_enter(sc->arpcom.ac_if.if_serializer);
        xl_stats_update_serialized(xsc);
        lwkt_serialize_exit(sc->arpcom.ac_if.if_serializer);
}

static void
xl_stats_update_serialized(void *xsc)
{
        struct xl_softc         *sc;
        struct ifnet            *ifp;
        struct xl_stats         xl_stats;
        u_int8_t                *p;
        int                     i;
        struct mii_data         *mii = NULL;

        bzero((char *)&xl_stats, sizeof(struct xl_stats));

        sc = xsc;
        ifp = &sc->arpcom.ac_if;
        if (sc->xl_miibus != NULL)
                mii = device_get_softc(sc->xl_miibus);

        p = (u_int8_t *)&xl_stats;

        /* Read all the stats registers. */
        XL_SEL_WIN(6);

        for (i = 0; i < 16; i++)
                *p++ = CSR_READ_1(sc, XL_W6_CARRIER_LOST + i);

        ifp->if_ierrors += xl_stats.xl_rx_overrun;

        ifp->if_collisions += xl_stats.xl_tx_multi_collision +
                                xl_stats.xl_tx_single_collision +
                                xl_stats.xl_tx_late_collision;

        /*
         * Boomerang and cyclone chips have an extra stats counter
         * in window 4 (BadSSD). We have to read this too in order
         * to clear out all the stats registers and avoid a statsoflow
         * interrupt.
         */
        XL_SEL_WIN(4);
        CSR_READ_1(sc, XL_W4_BADSSD);

        if ((mii != NULL) && (!sc->xl_stats_no_timeout))
                mii_tick(mii);

        XL_SEL_WIN(7);

        if (!sc->xl_stats_no_timeout)
                callout_reset(&sc->xl_stat_timer, hz, xl_stats_update, sc);

        return;
}

/*
 * Encapsulate an mbuf chain in a descriptor by coupling the mbuf data
 * pointers to the fragment pointers.
 */
static int
xl_encap(struct xl_softc *sc, struct xl_chain *c, struct mbuf *m_head)
{
        int                     error, nsegs, i;
        u_int32_t               status;
        bus_dma_segment_t       segs[XL_MAXFRAGS];
        struct xl_list          *l;

        error = bus_dmamap_load_mbuf_defrag(sc->xl_tx_mtag, c->xl_map, &m_head,
                        segs, XL_MAXFRAGS, &nsegs, BUS_DMA_NOWAIT);
        if (error) {
                m_freem(m_head);
                return error;
        }
        bus_dmamap_sync(sc->xl_tx_mtag, c->xl_map, BUS_DMASYNC_PREWRITE);

        if (sc->xl_type == XL_TYPE_905B) {
                status = XL_TXSTAT_RND_DEFEAT;
                if (m_head->m_pkthdr.csum_flags) {
                        if (m_head->m_pkthdr.csum_flags & CSUM_IP)
                                status |= XL_TXSTAT_IPCKSUM;
                        if (m_head->m_pkthdr.csum_flags & CSUM_TCP)
                                status |= XL_TXSTAT_TCPCKSUM;
                        if (m_head->m_pkthdr.csum_flags & CSUM_UDP)
                                status |= XL_TXSTAT_UDPCKSUM;
                }
        } else {
                status = m_head->m_pkthdr.len;
        }

        l = c->xl_ptr;
        for (i = 0; i < nsegs; i++) {
                l->xl_frag[i].xl_addr = htole32(segs[i].ds_addr);
                l->xl_frag[i].xl_len = htole32(segs[i].ds_len);
        }
        l->xl_frag[nsegs - 1].xl_len =
                htole32(segs[nsegs - 1].ds_len | XL_LAST_FRAG);
        l->xl_status = htole32(status);
        l->xl_next = 0;

        c->xl_mbuf = m_head;

        return(0);
}

static void
xl_start(struct ifnet *ifp)
{
        ASSERT_SERIALIZED(ifp->if_serializer);
        xl_start_body(ifp, 1);
}

#ifdef DEVICE_POLLING
static void
xl_start_poll(struct ifnet *ifp)
{
        xl_start_body(ifp, 0);
}
#endif

/*
 * 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
xl_start_body(struct ifnet *ifp, int proc_rx)
{
        struct xl_softc         *sc;
        struct mbuf             *m_head = NULL;
        struct xl_chain         *prev = NULL, *cur_tx = NULL, *start_tx;
        struct xl_chain         *prev_tx;
        u_int32_t               status;
        int                     error;

        sc = ifp->if_softc;
        /*
         * Check for an available queue slot. If there are none,
         * punt.
         */
        if (sc->xl_cdata.xl_tx_free == NULL) {
                xl_txeoc(sc);
                xl_txeof(sc);
                if (sc->xl_cdata.xl_tx_free == NULL) {
                        ifp->if_flags |= IFF_OACTIVE;
                        return;
                }
        }

        start_tx = sc->xl_cdata.xl_tx_free;

        while(sc->xl_cdata.xl_tx_free != NULL) {
                m_head = ifq_dequeue(&ifp->if_snd, NULL);
                if (m_head == NULL)
                        break;

                /* Pick a descriptor off the free list. */
                prev_tx = cur_tx;
                cur_tx = sc->xl_cdata.xl_tx_free;

                /* Pack the data into the descriptor. */
                error = xl_encap(sc, cur_tx, m_head);
                if (error) {
                        cur_tx = prev_tx;
                        continue;
                }

                sc->xl_cdata.xl_tx_free = cur_tx->xl_next;
                cur_tx->xl_next = NULL;

                /* Chain it together. */
                if (prev != NULL) {
                        prev->xl_next = cur_tx;
                        prev->xl_ptr->xl_next = htole32(cur_tx->xl_phys);
                }
                prev = cur_tx;

                BPF_MTAP(ifp, cur_tx->xl_mbuf);
        }

        /*
         * If there are no packets queued, bail.
         */
        if (cur_tx == NULL)
                return;

        /*
         * Place the request for the upload interrupt
         * in the last descriptor in the chain. This way, if
         * we're chaining several packets at once, we'll only
         * get an interupt once for the whole chain rather than
         * once for each packet.
         */
        cur_tx->xl_ptr->xl_status = htole32(le32toh(cur_tx->xl_ptr->xl_status) |
            XL_TXSTAT_DL_INTR);

        /*
         * Queue the packets. If the TX channel is clear, update
         * the downlist pointer register.
         */
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_DOWN_STALL);
        xl_wait(sc);

        if (sc->xl_cdata.xl_tx_head != NULL) {
                sc->xl_cdata.xl_tx_tail->xl_next = start_tx;
                sc->xl_cdata.xl_tx_tail->xl_ptr->xl_next =
                    htole32(start_tx->xl_phys);
                status = sc->xl_cdata.xl_tx_tail->xl_ptr->xl_status;
                sc->xl_cdata.xl_tx_tail->xl_ptr->xl_status =
                    htole32(le32toh(status) & ~XL_TXSTAT_DL_INTR);
                sc->xl_cdata.xl_tx_tail = cur_tx;
        } else {
                sc->xl_cdata.xl_tx_head = start_tx;
                sc->xl_cdata.xl_tx_tail = cur_tx;
        }

        if (!CSR_READ_4(sc, XL_DOWNLIST_PTR))
                CSR_WRITE_4(sc, XL_DOWNLIST_PTR, start_tx->xl_phys);

        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_DOWN_UNSTALL);

        XL_SEL_WIN(7);

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

        if (proc_rx) {
                /*
                 * XXX Under certain conditions, usually on slower machines
                 * where interrupts may be dropped, it's possible for the
                 * adapter to chew up all the buffers in the receive ring
                 * and stall, without us being able to do anything about it.
                 * To guard against this, we need to make a pass over the
                 * RX queue to make sure there aren't any packets pending.
                 * Doing it here means we can flush the receive ring at the
                 * same time the chip is DMAing the transmit descriptors we
                 * just gave it.
                 *
                 * 3Com goes to some lengths to emphasize the Parallel
                 * Tasking (tm) nature of their chips in all their marketing
                 * literature;  we may as well take advantage of it. :)
                 */
                xl_rxeof(sc, -1);
        }
}

static void
xl_start_90xB(struct ifnet *ifp)
{
        struct xl_softc         *sc;
        struct mbuf             *m_head = NULL;
        struct xl_chain         *prev = NULL, *cur_tx = NULL, *start_tx;
        struct xl_chain         *prev_tx;
        int                     error, idx;

        ASSERT_SERIALIZED(ifp->if_serializer);

        sc = ifp->if_softc;

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

        idx = sc->xl_cdata.xl_tx_prod;
        start_tx = &sc->xl_cdata.xl_tx_chain[idx];

        while (sc->xl_cdata.xl_tx_chain[idx].xl_mbuf == NULL) {

                if ((XL_TX_LIST_CNT - sc->xl_cdata.xl_tx_cnt) < 3) {
                        ifp->if_flags |= IFF_OACTIVE;
                        break;
                }

                m_head = ifq_dequeue(&ifp->if_snd, NULL);
                if (m_head == NULL)
                        break;

                prev_tx = cur_tx;
                cur_tx = &sc->xl_cdata.xl_tx_chain[idx];

                /* Pack the data into the descriptor. */
                error = xl_encap(sc, cur_tx, m_head);
                if (error) {
                        cur_tx = prev_tx;
                        continue;
                }

                /* Chain it together. */
                if (prev != NULL)
                        prev->xl_ptr->xl_next = htole32(cur_tx->xl_phys);
                prev = cur_tx;

                BPF_MTAP(ifp, cur_tx->xl_mbuf);

                XL_INC(idx, XL_TX_LIST_CNT);
                sc->xl_cdata.xl_tx_cnt++;
        }

        /*
         * If there are no packets queued, bail.
         */
        if (cur_tx == NULL)
                return;

        /*
         * Place the request for the upload interrupt
         * in the last descriptor in the chain. This way, if
         * we're chaining several packets at once, we'll only
         * get an interupt once for the whole chain rather than
         * once for each packet.
         */
        cur_tx->xl_ptr->xl_status = htole32(le32toh(cur_tx->xl_ptr->xl_status) |
            XL_TXSTAT_DL_INTR);

        /* Start transmission */
        sc->xl_cdata.xl_tx_prod = idx;
        start_tx->xl_prev->xl_ptr->xl_next = htole32(start_tx->xl_phys);

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

static void
xl_init(void *xsc)
{
        struct xl_softc         *sc = xsc;
        struct ifnet            *ifp = &sc->arpcom.ac_if;
        int                     error, i;
        u_int16_t               rxfilt = 0;
        struct mii_data         *mii = NULL;

        ASSERT_SERIALIZED(ifp->if_serializer);

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

        if (sc->xl_miibus == NULL) {
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_RESET);
                xl_wait(sc);
        }
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_RESET);
        xl_wait(sc);
        DELAY(10000);

        if (sc->xl_miibus != NULL)
                mii = device_get_softc(sc->xl_miibus);

        /* Init our MAC address */
        XL_SEL_WIN(2);
        for (i = 0; i < ETHER_ADDR_LEN; i++) {
                CSR_WRITE_1(sc, XL_W2_STATION_ADDR_LO + i,
                                sc->arpcom.ac_enaddr[i]);
        }

        /* Clear the station mask. */
        for (i = 0; i < 3; i++)
                CSR_WRITE_2(sc, XL_W2_STATION_MASK_LO + (i * 2), 0);
#ifdef notdef
        /* Reset TX and RX. */
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_RESET);
        xl_wait(sc);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_RESET);
        xl_wait(sc);
#endif
        /* Init circular RX list. */
        error = xl_list_rx_init(sc);
        if (error) {
                if_printf(ifp, "initialization of the rx ring failed (%d)\n",
                          error);
                xl_stop(sc);
                return;
        }

        /* Init TX descriptors. */
        if (sc->xl_type == XL_TYPE_905B)
                xl_list_tx_init_90xB(sc);
        else
                xl_list_tx_init(sc);

        /*
         * Set the TX freethresh value.
         * Note that this has no effect on 3c905B "cyclone"
         * cards but is required for 3c900/3c905 "boomerang"
         * cards in order to enable the download engine.
         */
        CSR_WRITE_1(sc, XL_TX_FREETHRESH, XL_PACKET_SIZE >> 8);

        /* Set the TX start threshold for best performance. */
        sc->xl_tx_thresh = XL_MIN_FRAMELEN;
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_SET_START|sc->xl_tx_thresh);

        /*
         * If this is a 3c905B, also set the tx reclaim threshold.
         * This helps cut down on the number of tx reclaim errors
         * that could happen on a busy network. The chip multiplies
         * the register value by 16 to obtain the actual threshold
         * in bytes, so we divide by 16 when setting the value here.
         * The existing threshold value can be examined by reading
         * the register at offset 9 in window 5.
         */
        if (sc->xl_type == XL_TYPE_905B) {
                CSR_WRITE_2(sc, XL_COMMAND,
                    XL_CMD_SET_TX_RECLAIM|(XL_PACKET_SIZE >> 4));
        }

        /* Set RX filter bits. */
        XL_SEL_WIN(5);
        rxfilt = CSR_READ_1(sc, XL_W5_RX_FILTER);

        /* Set the individual bit to receive frames for this host only. */
        rxfilt |= XL_RXFILTER_INDIVIDUAL;

        /* If we want promiscuous mode, set the allframes bit. */
        if (ifp->if_flags & IFF_PROMISC) {
                rxfilt |= XL_RXFILTER_ALLFRAMES;
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_FILT|rxfilt);
        } else {
                rxfilt &= ~XL_RXFILTER_ALLFRAMES;
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_FILT|rxfilt);
        }

        /*
         * Set capture broadcast bit to capture broadcast frames.
         */
        if (ifp->if_flags & IFF_BROADCAST) {
                rxfilt |= XL_RXFILTER_BROADCAST;
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_FILT|rxfilt);
        } else {
                rxfilt &= ~XL_RXFILTER_BROADCAST;
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_FILT|rxfilt);
        }

        /*
         * Program the multicast filter, if necessary.
         */
        if (sc->xl_type == XL_TYPE_905B)
                xl_setmulti_hash(sc);
        else
                xl_setmulti(sc);

        if (sc->xl_type == XL_TYPE_905B) {
                /* Set UP polling interval */
                CSR_WRITE_1(sc, XL_UP_POLL, 64);
        }

        /*
         * Load the address of the RX list. We have to
         * stall the upload engine before we can manipulate
         * the uplist pointer register, then unstall it when
         * we're finished. We also have to wait for the
         * stall command to complete before proceeding.
         * Note that we have to do this after any RX resets
         * have completed since the uplist register is cleared
         * by a reset.
         */
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_UP_STALL);
        xl_wait(sc);
        CSR_WRITE_4(sc, XL_UPLIST_PTR, sc->xl_ldata.xl_rx_dmaaddr);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_UP_UNSTALL);
        xl_wait(sc);

        if (sc->xl_type == XL_TYPE_905B) {
                /* Set DN polling interval */
                CSR_WRITE_1(sc, XL_DOWN_POLL, 64);

                /* Load the address of the TX list */
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_DOWN_STALL);
                xl_wait(sc);
                CSR_WRITE_4(sc, XL_DOWNLIST_PTR,
                    sc->xl_cdata.xl_tx_chain[0].xl_phys);
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_DOWN_UNSTALL);
                xl_wait(sc);
        }

        /*
         * If the coax transceiver is on, make sure to enable
         * the DC-DC converter.
         */
        XL_SEL_WIN(3);
        if (sc->xl_xcvr == XL_XCVR_COAX)
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_COAX_START);
        else
                CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_COAX_STOP);

        /*
         * increase packet size to allow reception of 802.1q or ISL packets.
         * For the 3c90x chip, set the 'allow large packets' bit in the MAC
         * control register. For 3c90xB/C chips, use the RX packet size
         * register.
         */
        
        if (sc->xl_type == XL_TYPE_905B) {
                CSR_WRITE_2(sc, XL_W3_MAXPKTSIZE, XL_PACKET_SIZE);
        } else {
                u_int8_t macctl;
                macctl = CSR_READ_1(sc, XL_W3_MAC_CTRL);
                macctl |= XL_MACCTRL_ALLOW_LARGE_PACK;
                CSR_WRITE_1(sc, XL_W3_MAC_CTRL, macctl);
        }

        /* Clear out the stats counters. */
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_STATS_DISABLE);
        sc->xl_stats_no_timeout = 1;
        xl_stats_update_serialized(sc);
        sc->xl_stats_no_timeout = 0;
        XL_SEL_WIN(4);
        CSR_WRITE_2(sc, XL_W4_NET_DIAG, XL_NETDIAG_UPPER_BYTES_ENABLE);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_STATS_ENABLE);

        /*
         * Enable interrupts.
         */
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_STAT_ENB | XL_INTRS);
#ifdef DEVICE_POLLING
        /* Do not enable interrupt if polling(4) is enabled */
        if ((ifp->if_flags & IFF_POLLING) != 0)
                xl_enable_intrs(sc, 0);
        else
#endif
        xl_enable_intrs(sc, XL_INTRS);

        /* Set the RX early threshold */
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_THRESH|(XL_PACKET_SIZE >>2));
        CSR_WRITE_2(sc, XL_DMACTL, XL_DMACTL_UP_RX_EARLY);

        /* Enable receiver and transmitter. */
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_ENABLE);
        xl_wait(sc);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_ENABLE);
        xl_wait(sc);

        if (mii != NULL)
                mii_mediachg(mii);

        /* Select window 7 for normal operations. */
        XL_SEL_WIN(7);

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

        callout_reset(&sc->xl_stat_timer, hz, xl_stats_update, sc);
}

/*
 * Set media options.
 */
static int
xl_ifmedia_upd(struct ifnet *ifp)
{
        struct xl_softc         *sc;
        struct ifmedia          *ifm = NULL;
        struct mii_data         *mii = NULL;

        ASSERT_SERIALIZED(ifp->if_serializer);

        sc = ifp->if_softc;
        if (sc->xl_miibus != NULL)
                mii = device_get_softc(sc->xl_miibus);
        if (mii == NULL)
                ifm = &sc->ifmedia;
        else
                ifm = &mii->mii_media;

        switch(IFM_SUBTYPE(ifm->ifm_media)) {
        case IFM_100_FX:
        case IFM_10_FL:
        case IFM_10_2:
        case IFM_10_5:
                xl_setmode(sc, ifm->ifm_media);
                return(0);
                break;
        default:
                break;
        }

        if (sc->xl_media & XL_MEDIAOPT_MII || sc->xl_media & XL_MEDIAOPT_BTX
                || sc->xl_media & XL_MEDIAOPT_BT4) {
                xl_init(sc);
        } else {
                xl_setmode(sc, ifm->ifm_media);
        }

        return(0);
}

/*
 * Report current media status.
 */
static void
xl_ifmedia_sts(struct ifnet *ifp, struct ifmediareq *ifmr)
{
        struct xl_softc         *sc;
        u_int32_t               icfg;
        struct mii_data         *mii = NULL;

        ASSERT_SERIALIZED(ifp->if_serializer);

        sc = ifp->if_softc;
        if (sc->xl_miibus != NULL)
                mii = device_get_softc(sc->xl_miibus);

        XL_SEL_WIN(3);
        icfg = CSR_READ_4(sc, XL_W3_INTERNAL_CFG) & XL_ICFG_CONNECTOR_MASK;
        icfg >>= XL_ICFG_CONNECTOR_BITS;

        ifmr->ifm_active = IFM_ETHER;

        switch(icfg) {
        case XL_XCVR_10BT:
                ifmr->ifm_active = IFM_ETHER|IFM_10_T;
                if (CSR_READ_1(sc, XL_W3_MAC_CTRL) & XL_MACCTRL_DUPLEX)
                        ifmr->ifm_active |= IFM_FDX;
                else
                        ifmr->ifm_active |= IFM_HDX;
                break;
        case XL_XCVR_AUI:
                if (sc->xl_type == XL_TYPE_905B &&
                    sc->xl_media == XL_MEDIAOPT_10FL) {
                        ifmr->ifm_active = IFM_ETHER|IFM_10_FL;
                        if (CSR_READ_1(sc, XL_W3_MAC_CTRL) & XL_MACCTRL_DUPLEX)
                                ifmr->ifm_active |= IFM_FDX;
                        else
                                ifmr->ifm_active |= IFM_HDX;
                } else
                        ifmr->ifm_active = IFM_ETHER|IFM_10_5;
                break;
        case XL_XCVR_COAX:
                ifmr->ifm_active = IFM_ETHER|IFM_10_2;
                break;
        /*
         * XXX MII and BTX/AUTO should be separate cases.
         */

        case XL_XCVR_100BTX:
        case XL_XCVR_AUTO:
        case XL_XCVR_MII:
                if (mii != NULL) {
                        mii_pollstat(mii);
                        ifmr->ifm_active = mii->mii_media_active;
                        ifmr->ifm_status = mii->mii_media_status;
                }
                break;
        case XL_XCVR_100BFX:
                ifmr->ifm_active = IFM_ETHER|IFM_100_FX;
                break;
        default:
                if_printf(ifp, "unknown XCVR type: %d\n", icfg);
                break;
        }

        return;
}

static int
xl_ioctl(struct ifnet *ifp, u_long command, caddr_t data, struct ucred *cr)
{
        struct xl_softc         *sc = ifp->if_softc;
        struct ifreq            *ifr = (struct ifreq *) data;
        int                     error = 0;
        struct mii_data         *mii = NULL;
        u_int8_t                rxfilt;

        ASSERT_SERIALIZED(ifp->if_serializer);

        switch(command) {
        case SIOCSIFFLAGS:
                XL_SEL_WIN(5);
                rxfilt = CSR_READ_1(sc, XL_W5_RX_FILTER);
                if (ifp->if_flags & IFF_UP) {
                        if (ifp->if_flags & IFF_RUNNING &&
                            ifp->if_flags & IFF_PROMISC &&
                            !(sc->xl_if_flags & IFF_PROMISC)) {
                                rxfilt |= XL_RXFILTER_ALLFRAMES;
                                CSR_WRITE_2(sc, XL_COMMAND,
                                    XL_CMD_RX_SET_FILT|rxfilt);
                                XL_SEL_WIN(7);
                        } else if (ifp->if_flags & IFF_RUNNING &&
                            !(ifp->if_flags & IFF_PROMISC) &&
                            sc->xl_if_flags & IFF_PROMISC) {
                                rxfilt &= ~XL_RXFILTER_ALLFRAMES;
                                CSR_WRITE_2(sc, XL_COMMAND,
                                    XL_CMD_RX_SET_FILT|rxfilt);
                                XL_SEL_WIN(7);
                        } else
                                xl_init(sc);
                } else {
                        if (ifp->if_flags & IFF_RUNNING)
                                xl_stop(sc);
                }
                sc->xl_if_flags = ifp->if_flags;
                error = 0;
                break;
        case SIOCADDMULTI:
        case SIOCDELMULTI:
                if (sc->xl_type == XL_TYPE_905B)
                        xl_setmulti_hash(sc);
                else
                        xl_setmulti(sc);
                error = 0;
                break;
        case SIOCGIFMEDIA:
        case SIOCSIFMEDIA:
                if (sc->xl_miibus != NULL)
                        mii = device_get_softc(sc->xl_miibus);
                if (mii == NULL)
                        error = ifmedia_ioctl(ifp, ifr,
                            &sc->ifmedia, command);
                else
                        error = ifmedia_ioctl(ifp, ifr,
                            &mii->mii_media, command);
                break;
        case SIOCSIFCAP:
                ifp->if_capenable &= ~IFCAP_HWCSUM;
                ifp->if_capenable |= (ifr->ifr_reqcap & IFCAP_HWCSUM);
                if (ifp->if_capenable & IFCAP_HWCSUM)
                        ifp->if_hwassist = XL905B_CSUM_FEATURES;
                else
                        ifp->if_hwassist = 0;
                break;
        default:
                error = ether_ioctl(ifp, command, data);
                break;
        }
        return(error);
}

static void
xl_watchdog(struct ifnet *ifp)
{
        struct xl_softc         *sc;
        u_int16_t               status = 0;

        ASSERT_SERIALIZED(ifp->if_serializer);

        sc = ifp->if_softc;

        ifp->if_oerrors++;
        XL_SEL_WIN(4);
        status = CSR_READ_2(sc, XL_W4_MEDIA_STATUS);
        if_printf(ifp, "watchdog timeout\n");

        if (status & XL_MEDIASTAT_CARRIER)
                if_printf(ifp, "no carrier - transceiver cable problem?\n");
        xl_txeoc(sc);
        xl_txeof(sc);
        xl_rxeof(sc, -1);
        xl_reset(sc);
        xl_init(sc);

        if (!ifq_is_empty(&ifp->if_snd))
                if_devstart(ifp);
}

/*
 * Stop the adapter and free any mbufs allocated to the
 * RX and TX lists.
 */
static void
xl_stop(struct xl_softc *sc)
{
        int             i;
        struct ifnet            *ifp;

        ifp = &sc->arpcom.ac_if;
        ASSERT_SERIALIZED(ifp->if_serializer);

        ifp->if_timer = 0;

        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_DISABLE);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_STATS_DISABLE);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_DISCARD);
        xl_wait(sc);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_DISABLE);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_COAX_STOP);
        DELAY(800);

#ifdef foo
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_RESET);
        xl_wait(sc);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_TX_RESET);
        xl_wait(sc);
#endif

        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ACK|XL_STAT_INTLATCH);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_STAT_ENB|0);
        CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|0);
        if (sc->xl_flags & XL_FLAG_FUNCREG)
                bus_space_write_4(sc->xl_ftag, sc->xl_fhandle, 4, 0x8000);

        /* Stop the stats updater. */
        callout_stop(&sc->xl_stat_timer);

        /*
         * Free data in the RX lists.
         */
        for (i = 0; i < XL_RX_LIST_CNT; i++) {
                if (sc->xl_cdata.xl_rx_chain[i].xl_mbuf != NULL) {
                        bus_dmamap_unload(sc->xl_rx_mtag,
                            sc->xl_cdata.xl_rx_chain[i].xl_map);
                        m_freem(sc->xl_cdata.xl_rx_chain[i].xl_mbuf);
                        sc->xl_cdata.xl_rx_chain[i].xl_mbuf = NULL;
                }
        }
        bzero(sc->xl_ldata.xl_rx_list, XL_RX_LIST_SZ);

        /*
         * Free the TX list buffers.
         */
        for (i = 0; i < XL_TX_LIST_CNT; i++) {
                if (sc->xl_cdata.xl_tx_chain[i].xl_mbuf != NULL) {
                        bus_dmamap_unload(sc->xl_tx_mtag,
                            sc->xl_cdata.xl_tx_chain[i].xl_map);
                        m_freem(sc->xl_cdata.xl_tx_chain[i].xl_mbuf);
                        sc->xl_cdata.xl_tx_chain[i].xl_mbuf = NULL;
                }
        }
        bzero(sc->xl_ldata.xl_tx_list, XL_TX_LIST_SZ);

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

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

        lwkt_serialize_enter(sc->arpcom.ac_if.if_serializer);
        xl_reset(sc);
        xl_stop(sc);
        lwkt_serialize_exit(sc->arpcom.ac_if.if_serializer);
}

static int
xl_suspend(device_t dev)
{
        struct xl_softc *sc = device_get_softc(dev);

        lwkt_serialize_enter(sc->arpcom.ac_if.if_serializer);
        xl_stop(sc);
        lwkt_serialize_exit(sc->arpcom.ac_if.if_serializer);

        return(0);
}

static int
xl_resume(device_t dev)
{
        struct xl_softc         *sc;
        struct ifnet            *ifp;

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

        lwkt_serialize_enter(ifp->if_serializer);
        xl_reset(sc);
        if (ifp->if_flags & IFF_UP)
                xl_init(sc);
        lwkt_serialize_exit(ifp->if_serializer);

        return(0);
}