FreeBSD/Linux Kernel Cross Reference
sys/dev/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.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    /*
     * 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.
     */
   
   #ifdef HAVE_KERNEL_OPTION_HEADERS
   #include "opt_device_polling.h"
   #endif
   
   #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/module.h>
   #include <sys/socket.h>
   #include <sys/taskqueue.h>
   
   #include <net/if.h>
   #include <net/if_arp.h>
   #include <net/ethernet.h>
   #include <net/if_dl.h>
   #include <net/if_media.h>
   #include <net/if_types.h>
   
   #include <net/bpf.h>
   
   #include <machine/bus.h>
   #include <machine/resource.h>
   #include <sys/bus.h>
   #include <sys/rman.h>
   
   #include <dev/mii/mii.h>
   #include <dev/mii/mii_bitbang.h>
   #include <dev/mii/miivar.h>
   
   #include <dev/pci/pcireg.h>
   #include <dev/pci/pcivar.h>
   
   MODULE_DEPEND(xl, pci, 1, 1, 1);
   MODULE_DEPEND(xl, ether, 1, 1, 1);
   MODULE_DEPEND(xl, miibus, 1, 1, 1);
   
   /* "device miibus" required.  See GENERIC if you get errors here. */
   #include "miibus_if.h"
   
   #include <dev/xl/if_xlreg.h>
   
   /*
    * TX Checksumming is disabled by default for two reasons:
    * - TX Checksumming will occasionally produce corrupt packets
    * - TX Checksumming seems to reduce performance
    *
    * Only 905B/C cards were reported to have this problem, it is possible
    * that later chips _may_ be immune.
    */
   #define XL905B_TXCSUM_BROKEN    1
   
   #ifdef XL905B_TXCSUM_BROKEN
   #define XL905B_CSUM_FEATURES    0
   #else
   #define XL905B_CSUM_FEATURES    (CSUM_IP | CSUM_TCP | CSUM_UDP)
   #endif
   
   /*
    * Various supported device vendors/types and their names.
    */
   static const 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_TORNADO_10_100BT_920B_WNM,
                   "3Com 3c920B-EMB-WNM 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 int xl_newbuf(struct xl_softc *, struct xl_chain_onefrag *);
   static void xl_tick(void *);
   static void xl_stats_update(struct xl_softc *);
   static int xl_encap(struct xl_softc *, struct xl_chain *, struct mbuf **);
   static int xl_rxeof(struct xl_softc *);
   static void xl_rxeof_task(void *, 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(struct ifnet *);
   static void xl_start_locked(struct ifnet *);
   static void xl_start_90xB_locked(struct ifnet *);
   static int xl_ioctl(struct ifnet *, u_long, caddr_t);
   static void xl_init(void *);
   static void xl_init_locked(struct xl_softc *);
   static void xl_stop(struct xl_softc *);
   static int xl_watchdog(struct xl_softc *);
   static int xl_shutdown(device_t);
   static int xl_suspend(device_t);
   static int xl_resume(device_t);
   static void xl_setwol(struct xl_softc *);
   
   #ifdef DEVICE_POLLING
   static int xl_poll(struct ifnet *ifp, enum poll_cmd cmd, int count);
   static int xl_poll_locked(struct ifnet *ifp, enum poll_cmd cmd, int count);
   #endif
   
   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_rxfilter(struct xl_softc *);
   static void xl_rxfilter_90x(struct xl_softc *);
   static void xl_rxfilter_90xB(struct xl_softc *);
   static void xl_setcfg(struct xl_softc *);
   static void xl_setmode(struct xl_softc *, int);
   static void xl_reset(struct xl_softc *);
   static int xl_list_rx_init(struct xl_softc *);
   static int xl_list_tx_init(struct xl_softc *);
   static int 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_media(struct xl_softc *sc, int *media);
   static void xl_choose_xcvr(struct xl_softc *, int);
   static void xl_dma_map_addr(void *, bus_dma_segment_t *, int, int);
   #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);
   
   /*
    * MII bit-bang glue
    */
   static uint32_t xl_mii_bitbang_read(device_t);
   static void xl_mii_bitbang_write(device_t, uint32_t);
   
   static const struct mii_bitbang_ops xl_mii_bitbang_ops = {
           xl_mii_bitbang_read,
           xl_mii_bitbang_write,
           {
                   XL_MII_DATA,            /* MII_BIT_MDO */
                   XL_MII_DATA,            /* MII_BIT_MDI */
                   XL_MII_CLK,             /* MII_BIT_MDC */
                   XL_MII_DIR,             /* MII_BIT_DIR_HOST_PHY */
                   0,                      /* MII_BIT_DIR_PHY_HOST */
           }
   };
   
   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),
   
           /* 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),
   
           DEVMETHOD_END
   };
   
   static driver_t xl_driver = {
           "xl",
           xl_methods,
           sizeof(struct xl_softc)
   };
   
   static devclass_t xl_devclass;
   
   DRIVER_MODULE_ORDERED(xl, pci, xl_driver, xl_devclass, NULL, NULL,
       SI_ORDER_ANY);
   DRIVER_MODULE(miibus, xl, miibus_driver, miibus_devclass, NULL, NULL);
   
   static void
   xl_dma_map_addr(void *arg, bus_dma_segment_t *segs, int nseg, int error)
   {
           u_int32_t *paddr;
   
           paddr = arg;
           *paddr = segs->ds_addr;
   }
   
   /*
    * 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.  Suppress warning when card gone.
    */
   static void
   xl_wait(struct xl_softc *sc)
   {
           register int            i;
   
           for (i = 0; i < XL_TIMEOUT; i++) {
                   if ((CSR_READ_2(sc, XL_STATUS) & XL_STAT_CMDBUSY) == 0)
                           break;
           }
   
           if (i == XL_TIMEOUT && bus_child_present(sc->xl_dev))
                   device_printf(sc->xl_dev, "command never completed!\n");
   }
   
   /*
    * 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.
    */
   
   /*
    * Read the MII serial port for the MII bit-bang module.
    */
   static uint32_t
   xl_mii_bitbang_read(device_t dev)
   {
           struct xl_softc         *sc;
           uint32_t                val;
   
           sc = device_get_softc(dev);
   
           /* We're already in window 4. */
           val = CSR_READ_2(sc, XL_W4_PHY_MGMT);
           CSR_BARRIER(sc, XL_W4_PHY_MGMT, 2,
               BUS_SPACE_BARRIER_READ | BUS_SPACE_BARRIER_WRITE);
   
           return (val);
   }
   
   /*
    * Write the MII serial port for the MII bit-bang module.
    */
   static void
   xl_mii_bitbang_write(device_t dev, uint32_t val)
   {
           struct xl_softc         *sc;
   
           sc = device_get_softc(dev);
   
           /* We're already in window 4. */
           CSR_WRITE_2(sc, XL_W4_PHY_MGMT, val);
           CSR_BARRIER(sc, XL_W4_PHY_MGMT, 2,
               BUS_SPACE_BARRIER_READ | BUS_SPACE_BARRIER_WRITE);
   }
   
   static int
   xl_miibus_readreg(device_t dev, int phy, int reg)
   {
           struct xl_softc         *sc;
   
           sc = device_get_softc(dev);
   
           /* Select the window 4. */
           XL_SEL_WIN(4);
   
           return (mii_bitbang_readreg(dev, &xl_mii_bitbang_ops, phy, reg));
   }
   
   static int
   xl_miibus_writereg(device_t dev, int phy, int reg, int data)
   {
           struct xl_softc         *sc;
   
           sc = device_get_softc(dev);
   
           /* Select the window 4. */
           XL_SEL_WIN(4);
   
           mii_bitbang_writereg(dev, &xl_mii_bitbang_ops, phy, reg, data);
   
           return (0);
   }
   
   static void
   xl_miibus_statchg(device_t dev)
   {
           struct xl_softc         *sc;
           struct mii_data         *mii;
           uint8_t                 macctl;
   
           sc = device_get_softc(dev);
           mii = device_get_softc(sc->xl_miibus);
   
           xl_setcfg(sc);
   
           /* Set ASIC's duplex mode to match the PHY. */
           XL_SEL_WIN(3);
           macctl = CSR_READ_1(sc, XL_W3_MAC_CTRL);
           if ((IFM_OPTIONS(mii->mii_media_active) & IFM_FDX) != 0) {
                   macctl |= XL_MACCTRL_DUPLEX;
                   if (sc->xl_type == XL_TYPE_905B) {
                           if ((IFM_OPTIONS(mii->mii_media_active) &
                               IFM_ETH_RXPAUSE) != 0)
                                   macctl |= XL_MACCTRL_FLOW_CONTROL_ENB;
                           else
                                   macctl &= ~XL_MACCTRL_FLOW_CONTROL_ENB;
                   }
           } else {
                   macctl &= ~XL_MACCTRL_DUPLEX;
                   if (sc->xl_type == XL_TYPE_905B)
                           macctl &= ~XL_MACCTRL_FLOW_CONTROL_ENB;
           }
           CSR_WRITE_1(sc, XL_W3_MAC_CTRL, macctl);
   }
   
   /*
    * 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(sc->xl_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(sc->xl_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(sc->xl_dev, "found BNC\n");
                   ifmedia_add(ifm, IFM_ETHER | IFM_10_2, 0, NULL);
           }
   }
   
   /*
    * 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) {
                   device_printf(sc->xl_dev, "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)
           /*
            * XXX: 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);
   }
   
   static void
   xl_rxfilter(struct xl_softc *sc)
   {
   
           if (sc->xl_type == XL_TYPE_905B)
                   xl_rxfilter_90xB(sc);
           else
                   xl_rxfilter_90x(sc);
   }
   
   /*
    * NICs older than the 3c905B have only one multicast option, which
    * is to enable reception of all multicast frames.
    */
   static void
   xl_rxfilter_90x(struct xl_softc *sc)
   {
           struct ifnet            *ifp;
           struct ifmultiaddr      *ifma;
           u_int8_t                rxfilt;
   
           XL_LOCK_ASSERT(sc);
   
           ifp = sc->xl_ifp;
   
           XL_SEL_WIN(5);
           rxfilt = CSR_READ_1(sc, XL_W5_RX_FILTER);
           rxfilt &= ~(XL_RXFILTER_ALLFRAMES | XL_RXFILTER_ALLMULTI |
               XL_RXFILTER_BROADCAST | XL_RXFILTER_INDIVIDUAL);
   
           /* Set the individual bit to receive frames for this host only. */
           rxfilt |= XL_RXFILTER_INDIVIDUAL;
           /* Set capture broadcast bit to capture broadcast frames. */
           if (ifp->if_flags & IFF_BROADCAST)
                   rxfilt |= XL_RXFILTER_BROADCAST;
   
           /* If we want promiscuous mode, set the allframes bit. */
           if (ifp->if_flags & (IFF_PROMISC | IFF_ALLMULTI)) {
                   if (ifp->if_flags & IFF_PROMISC)
                           rxfilt |= XL_RXFILTER_ALLFRAMES;
                   if (ifp->if_flags & IFF_ALLMULTI)
                           rxfilt |= XL_RXFILTER_ALLMULTI;
           } else {
                   if_maddr_rlock(ifp);
                   TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
                           if (ifma->ifma_addr->sa_family != AF_LINK)
                                   continue;
                           rxfilt |= XL_RXFILTER_ALLMULTI;
                           break;
                   }
                   if_maddr_runlock(ifp);
           }
   
           CSR_WRITE_2(sc, XL_COMMAND, rxfilt | XL_CMD_RX_SET_FILT);
           XL_SEL_WIN(7);
   }
   
   /*
    * 3c905B adapters have a hash filter that we can program.
    */
   static void
   xl_rxfilter_90xB(struct xl_softc *sc)
   {
           struct ifnet            *ifp;
           struct ifmultiaddr      *ifma;
           int                     i, mcnt;
           u_int16_t               h;
           u_int8_t                rxfilt;
   
           XL_LOCK_ASSERT(sc);
   
           ifp = sc->xl_ifp;
   
           XL_SEL_WIN(5);
           rxfilt = CSR_READ_1(sc, XL_W5_RX_FILTER);
           rxfilt &= ~(XL_RXFILTER_ALLFRAMES | XL_RXFILTER_ALLMULTI |
               XL_RXFILTER_BROADCAST | XL_RXFILTER_INDIVIDUAL |
               XL_RXFILTER_MULTIHASH);
   
           /* Set the individual bit to receive frames for this host only. */
           rxfilt |= XL_RXFILTER_INDIVIDUAL;
           /* Set capture broadcast bit to capture broadcast frames. */
           if (ifp->if_flags & IFF_BROADCAST)
                   rxfilt |= XL_RXFILTER_BROADCAST;
   
           /* If we want promiscuous mode, set the allframes bit. */
           if (ifp->if_flags & (IFF_PROMISC | IFF_ALLMULTI)) {
                   if (ifp->if_flags & IFF_PROMISC)
                           rxfilt |= XL_RXFILTER_ALLFRAMES;
                   if (ifp->if_flags & IFF_ALLMULTI)
                           rxfilt |= XL_RXFILTER_ALLMULTI;
           } else {
                   /* 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. */
                   mcnt = 0;
                   if_maddr_rlock(ifp);
                   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,
                               h | XL_CMD_RX_SET_HASH | XL_HASH_SET);
                           mcnt++;
                   }
                   if_maddr_runlock(ifp);
                   if (mcnt > 0)
                           rxfilt |= XL_RXFILTER_MULTIHASH;
           }
   
           CSR_WRITE_2(sc, XL_COMMAND, rxfilt | XL_CMD_RX_SET_FILT);
           XL_SEL_WIN(7);
   }
   
   static void
   xl_setcfg(struct xl_softc *sc)
   {
           u_int32_t               icfg;
   
           /*XL_LOCK_ASSERT(sc);*/
   
           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);
   }
   
   static void
   xl_setmode(struct xl_softc *sc, int media)
   {
           u_int32_t               icfg;
           u_int16_t               mediastat;
           char                    *pmsg = "", *dmsg = "";
   
           XL_LOCK_ASSERT(sc);
   
           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) {
                           pmsg = "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) {
                           pmsg = "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) {
                           pmsg = "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) {
                           pmsg = "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) {
                           pmsg = "AUI 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) {
                   dmsg = "full";
                   XL_SEL_WIN(3);
                   CSR_WRITE_1(sc, XL_W3_MAC_CTRL, XL_MACCTRL_DUPLEX);
           } else {
                   dmsg = "half";
                   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);
   
           device_printf(sc->xl_dev, "selecting %s, %s duplex\n", pmsg, dmsg);
   }
   
   static void
   xl_reset(struct xl_softc *sc)
   {
           register int            i;
   
           XL_LOCK_ASSERT(sc);
   
           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)
                   device_printf(sc->xl_dev, "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);
   }
   
   /*
    * 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)
   {
           const struct xl_type    *t;
   
           t = xl_devs;
   
           while (t->xl_name != NULL) {
                   if ((pci_get_vendor(dev) == t->xl_vid) &&
                       (pci_get_device(dev) == t->xl_did)) {
                           device_set_desc(dev, t->xl_name);
                           return (BUS_PROBE_DEFAULT);
                   }
                   t++;
           }
   
           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)
   {
   
           /*
            * 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 {
                           device_printf(sc->xl_dev,
                               "bogus xcvr value in EEPROM (%x)\n", sc->xl_xcvr);
                           device_printf(sc->xl_dev,
                               "choosing new default based on card type\n");
                   }
           } else {
                   if (sc->xl_type == XL_TYPE_905B &&
                       sc->xl_media & XL_MEDIAOPT_10FL)
                           return;
                   device_printf(sc->xl_dev,
   "WARNING: no media options bits set in the media options register!!\n");
                   device_printf(sc->xl_dev,
   "this could be a manufacturing defect in your adapter or system\n");
                   device_printf(sc->xl_dev,
   "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)
   {
           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)
                           device_printf(sc->xl_dev,
                               "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)
                           device_printf(sc->xl_dev,
                               "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)
                           device_printf(sc->xl_dev, "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)
                          device_printf(sc->xl_dev, "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 */
          case TC_DEVICEID_TORNADO_10_100BT_920B_WNM:     /* 3c920B-EMB-WNM */
                  sc->xl_media = XL_MEDIAOPT_MII;
                  sc->xl_xcvr = XL_XCVR_MII;
                  if (verbose)
                          device_printf(sc->xl_dev, "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)
                          device_printf(sc->xl_dev, "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)
                          device_printf(sc->xl_dev, "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)
                          device_printf(sc->xl_dev,
                              "guessing 10/100 plus BNC/AUI\n");
                  break;
          default:
                  device_printf(sc->xl_dev,
                      "unknown device ID: %x -- defaulting to 10baseT\n", devid);
                  sc->xl_media = XL_MEDIAOPT_BT;
                  break;
          }
  }
  
  /*
   * 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               sinfo2, xcvr[2];
          struct xl_softc         *sc;
          struct ifnet            *ifp;
          int                     media, pmcap;
          int                     error = 0, phy, rid, res, unit;
          uint16_t                did;
  
          sc = device_get_softc(dev);
          sc->xl_dev = dev;
  
          unit = device_get_unit(dev);
  
          mtx_init(&sc->xl_mtx, device_get_nameunit(dev), MTX_NETWORK_LOCK,
              MTX_DEF);
          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 ||
              did == TC_DEVICEID_TORNADO_10_100BT_920B_WNM)
                  sc->xl_flags |= XL_FLAG_PHYOK;
  
          switch (did) {
          case TC_DEVICEID_BOOMERANG_10_100BT:    /* 3c905-TX */
          case TC_DEVICEID_HURRICANE_575A:
          case TC_DEVICEID_HURRICANE_575B:
          case TC_DEVICEID_HURRICANE_575C:
                  sc->xl_flags |= XL_FLAG_NO_MMIO;
                  break;
          default:
                  break;
          }
  
          /*
           * Map control/status registers.
           */
          pci_enable_busmaster(dev);
  
          if ((sc->xl_flags & XL_FLAG_NO_MMIO) == 0) {
                  rid = XL_PCI_LOMEM;
                  res = SYS_RES_MEMORY;
  
                  sc->xl_res = bus_alloc_resource_any(dev, res, &rid, RF_ACTIVE);
          }
  
          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;
          }
  
          /* Initialize interface name. */
          ifp = sc->xl_ifp = if_alloc(IFT_ETHER);
          if (ifp == NULL) {
                  device_printf(dev, "can not if_alloc()\n");
                  error = ENOSPC;
                  goto fail;
          }
          ifp->if_softc = sc;
          if_initname(ifp, device_get_name(dev), device_get_unit(dev));
  
          /* Reset the adapter. */
          XL_LOCK(sc);
          xl_reset(sc);
          XL_UNLOCK(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_mtx(&sc->xl_tick_callout, &sc->xl_mtx, 0);
          TASK_INIT(&sc->xl_task, 0, xl_rxeof_task, sc);
  
          /*
           * 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_dma_tag_create(bus_get_dma_tag(dev), 8, 0,
              BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL, NULL,
              XL_RX_LIST_SZ, 1, XL_RX_LIST_SZ, 0, NULL, NULL,
              &sc->xl_ldata.xl_rx_tag);
          if (error) {
                  device_printf(dev, "failed to allocate rx dma tag\n");
                  goto fail;
          }
  
          error = bus_dmamem_alloc(sc->xl_ldata.xl_rx_tag,
              (void **)&sc->xl_ldata.xl_rx_list, BUS_DMA_NOWAIT |
              BUS_DMA_COHERENT | BUS_DMA_ZERO, &sc->xl_ldata.xl_rx_dmamap);
          if (error) {
                  device_printf(dev, "no memory for rx list buffers!\n");
                  bus_dma_tag_destroy(sc->xl_ldata.xl_rx_tag);
                  sc->xl_ldata.xl_rx_tag = NULL;
                  goto fail;
          }
  
          error = bus_dmamap_load(sc->xl_ldata.xl_rx_tag,
              sc->xl_ldata.xl_rx_dmamap, sc->xl_ldata.xl_rx_list,
              XL_RX_LIST_SZ, xl_dma_map_addr,
              &sc->xl_ldata.xl_rx_dmaaddr, BUS_DMA_NOWAIT);
          if (error) {
                  device_printf(dev, "cannot get dma address of the rx ring!\n");
                  bus_dmamem_free(sc->xl_ldata.xl_rx_tag, sc->xl_ldata.xl_rx_list,
                      sc->xl_ldata.xl_rx_dmamap);
                  bus_dma_tag_destroy(sc->xl_ldata.xl_rx_tag);
                  sc->xl_ldata.xl_rx_tag = NULL;
                  goto fail;
          }
  
          error = bus_dma_tag_create(bus_get_dma_tag(dev), 8, 0,
              BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL, NULL,
              XL_TX_LIST_SZ, 1, XL_TX_LIST_SZ, 0, NULL, NULL,
              &sc->xl_ldata.xl_tx_tag);
          if (error) {
                  device_printf(dev, "failed to allocate tx dma tag\n");
                  goto fail;
          }
  
          error = bus_dmamem_alloc(sc->xl_ldata.xl_tx_tag,
              (void **)&sc->xl_ldata.xl_tx_list, BUS_DMA_NOWAIT |
              BUS_DMA_COHERENT | BUS_DMA_ZERO, &sc->xl_ldata.xl_tx_dmamap);
          if (error) {
                  device_printf(dev, "no memory for list buffers!\n");
                  bus_dma_tag_destroy(sc->xl_ldata.xl_tx_tag);
                  sc->xl_ldata.xl_tx_tag = NULL;
                  goto fail;
          }
  
          error = bus_dmamap_load(sc->xl_ldata.xl_tx_tag,
              sc->xl_ldata.xl_tx_dmamap, sc->xl_ldata.xl_tx_list,
              XL_TX_LIST_SZ, xl_dma_map_addr,
              &sc->xl_ldata.xl_tx_dmaaddr, BUS_DMA_NOWAIT);
          if (error) {
                  device_printf(dev, "cannot get dma address of the tx ring!\n");
                  bus_dmamem_free(sc->xl_ldata.xl_tx_tag, sc->xl_ldata.xl_tx_list,
                      sc->xl_ldata.xl_tx_dmamap);
                  bus_dma_tag_destroy(sc->xl_ldata.xl_tx_tag);
                  sc->xl_ldata.xl_tx_tag = NULL;
                  goto fail;
          }
  
          /*
           * Allocate a DMA tag for the mapping of mbufs.
           */
          error = bus_dma_tag_create(bus_get_dma_tag(dev), 1, 0,
              BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL, NULL,
              MCLBYTES * XL_MAXFRAGS, XL_MAXFRAGS, MCLBYTES, 0, NULL,
              NULL, &sc->xl_mtag);
          if (error) {
                  device_printf(dev, "failed to allocate mbuf dma tag\n");
                  goto fail;
          }
  
          /* We need a spare DMA map for the RX ring. */
          error = bus_dmamap_create(sc->xl_mtag, 0, &sc->xl_tmpmap);
          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;
  
          /* Check availability of WOL. */
          if ((sc->xl_caps & XL_CAPS_PWRMGMT) != 0 &&
              pci_find_cap(dev, PCIY_PMG, &pmcap) == 0) {
                  sc->xl_pmcap = pmcap;
                  sc->xl_flags |= XL_FLAG_WOL;
                  sinfo2 = 0;
                  xl_read_eeprom(sc, (caddr_t)&sinfo2, XL_EE_SOFTINFO2, 1, 0);
                  if ((sinfo2 & XL_SINFO2_AUX_WOL_CON) == 0 && bootverbose)
                          device_printf(dev,
                              "No auxiliary remote wakeup connector!\n");
          }
  
          /* Set the TX start threshold for best performance. */
          sc->xl_tx_thresh = XL_MIN_FRAMELEN;
  
          ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
          ifp->if_ioctl = xl_ioctl;
          ifp->if_capabilities = IFCAP_VLAN_MTU;
          if (sc->xl_type == XL_TYPE_905B) {
                  ifp->if_hwassist = XL905B_CSUM_FEATURES;
  #ifdef XL905B_TXCSUM_BROKEN
                  ifp->if_capabilities |= IFCAP_RXCSUM;
  #else
                  ifp->if_capabilities |= IFCAP_HWCSUM;
  #endif
          }
          if ((sc->xl_flags & XL_FLAG_WOL) != 0)
                  ifp->if_capabilities |= IFCAP_WOL_MAGIC;
          ifp->if_capenable = ifp->if_capabilities;
  #ifdef DEVICE_POLLING
          ifp->if_capabilities |= IFCAP_POLLING;
  #endif
          ifp->if_start = xl_start;
          ifp->if_init = xl_init;
          IFQ_SET_MAXLEN(&ifp->if_snd, XL_TX_LIST_CNT - 1);
          ifp->if_snd.ifq_drv_maxlen = XL_TX_LIST_CNT - 1;
          IFQ_SET_READY(&ifp->if_snd);
  
          /*
           * 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)
                  device_printf(dev, "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)
                          device_printf(dev, "found MII/AUTO\n");
                  xl_setcfg(sc);
                  /*
                   * Attach PHYs only at MII address 24 if !XL_FLAG_PHYOK.
                   * This is to guard against problems with certain 3Com ASIC
                   * revisions that incorrectly map the internal transceiver
                   * control registers at all MII addresses.
                   */
                  phy = MII_PHY_ANY;
                  if ((sc->xl_flags & XL_FLAG_PHYOK) == 0)
                          phy = 24;
                  error = mii_attach(dev, &sc->xl_miibus, ifp, xl_ifmedia_upd,
                      xl_ifmedia_sts, BMSR_DEFCAPMASK, phy, MII_OFFSET_ANY,
                      sc->xl_type == XL_TYPE_905B ? MIIF_DOPAUSE : 0);
                  if (error != 0) {
                          device_printf(dev, "attaching PHYs failed\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)
                          device_printf(dev, "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)
                                  device_printf(dev, "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)
                                  device_printf(dev, "found AUI\n");
                          ifmedia_add(&sc->ifmedia, IFM_ETHER|IFM_10_5, 0, NULL);
                  }
          }
  
          if (sc->xl_media & XL_MEDIAOPT_BNC) {
                  if (bootverbose)
                          device_printf(dev, "found BNC\n");
                  ifmedia_add(&sc->ifmedia, IFM_ETHER|IFM_10_2, 0, NULL);
          }
  
          if (sc->xl_media & XL_MEDIAOPT_BFX) {
                  if (bootverbose)
                          device_printf(dev, "found 100baseFX\n");
                  ifmedia_add(&sc->ifmedia, IFM_ETHER|IFM_100_FX, 0, NULL);
          }
  
          media = IFM_ETHER|IFM_100_TX|IFM_FDX;
          xl_choose_media(sc, &media);
  
          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);
  
          error = bus_setup_intr(dev, sc->xl_irq, INTR_TYPE_NET | INTR_MPSAFE,
              NULL, xl_intr, sc, &sc->xl_intrhand);
          if (error) {
                  device_printf(dev, "couldn't set up irq\n");
                  ether_ifdetach(ifp);
                  goto fail;
          }
  
  fail:
          if (error)
                  xl_detach(dev);
  
          return (error);
  }
  
  /*
   * Choose a default media.
   * XXX This is a leaf function only called by xl_attach() and
   *     acquires/releases the non-recursible driver mutex to
   *     satisfy lock assertions.
   */
  static void
  xl_choose_media(struct xl_softc *sc, int *media)
  {
  
          XL_LOCK(sc);
  
          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:
                  device_printf(sc->xl_dev, "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;
          }
  
          XL_UNLOCK(sc);
  }
  
  /*
   * 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->xl_ifp;
  
          KASSERT(mtx_initialized(&sc->xl_mtx), ("xl mutex not initialized"));
  
  #ifdef DEVICE_POLLING
          if (ifp && ifp->if_capenable & IFCAP_POLLING)
                  ether_poll_deregister(ifp);
  #endif
  
          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;
          }
  
          /* These should only be active if attach succeeded */
          if (device_is_attached(dev)) {
                  XL_LOCK(sc);
                  xl_stop(sc);
                  XL_UNLOCK(sc);
                  taskqueue_drain(taskqueue_swi, &sc->xl_task);
                  callout_drain(&sc->xl_tick_callout);
                  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_intrhand)
                  bus_teardown_intr(dev, sc->xl_irq, sc->xl_intrhand);
          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);
  
          if (ifp)
                  if_free(ifp);
  
          if (sc->xl_mtag) {
                  bus_dmamap_destroy(sc->xl_mtag, sc->xl_tmpmap);
                  bus_dma_tag_destroy(sc->xl_mtag);
          }
          if (sc->xl_ldata.xl_rx_tag) {
                  bus_dmamap_unload(sc->xl_ldata.xl_rx_tag,
                      sc->xl_ldata.xl_rx_dmamap);
                  bus_dmamem_free(sc->xl_ldata.xl_rx_tag, sc->xl_ldata.xl_rx_list,
                      sc->xl_ldata.xl_rx_dmamap);
                  bus_dma_tag_destroy(sc->xl_ldata.xl_rx_tag);
          }
          if (sc->xl_ldata.xl_tx_tag) {
                  bus_dmamap_unload(sc->xl_ldata.xl_tx_tag,
                      sc->xl_ldata.xl_tx_dmamap);
                  bus_dmamem_free(sc->xl_ldata.xl_tx_tag, sc->xl_ldata.xl_tx_list,
                      sc->xl_ldata.xl_tx_dmamap);
                  bus_dma_tag_destroy(sc->xl_ldata.xl_tx_tag);
          }
  
          mtx_destroy(&sc->xl_mtx);
  
          return (0);
  }
  
  /*
   * Initialize the transmit descriptors.
   */
  static int
  xl_list_tx_init(struct xl_softc *sc)
  {
          struct xl_chain_data    *cd;
          struct xl_list_data     *ld;
          int                     error, i;
  
          XL_LOCK_ASSERT(sc);
  
          cd = &sc->xl_cdata;
          ld = &sc->xl_ldata;
          for (i = 0; i < XL_TX_LIST_CNT; i++) {
                  cd->xl_tx_chain[i].xl_ptr = &ld->xl_tx_list[i];
                  error = bus_dmamap_create(sc->xl_mtag, 0,
                      &cd->xl_tx_chain[i].xl_map);
                  if (error)
                          return (error);
                  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;
  
          bus_dmamap_sync(ld->xl_tx_tag, ld->xl_tx_dmamap, BUS_DMASYNC_PREWRITE);
          return (0);
  }
  
  /*
   * Initialize the transmit descriptors.
   */
  static int
  xl_list_tx_init_90xB(struct xl_softc *sc)
  {
          struct xl_chain_data    *cd;
          struct xl_list_data     *ld;
          int                     error, i;
  
          XL_LOCK_ASSERT(sc);
  
          cd = &sc->xl_cdata;
          ld = &sc->xl_ldata;
          for (i = 0; i < XL_TX_LIST_CNT; i++) {
                  cd->xl_tx_chain[i].xl_ptr = &ld->xl_tx_list[i];
                  error = bus_dmamap_create(sc->xl_mtag, 0,
                      &cd->xl_tx_chain[i].xl_map);
                  if (error)
                          return (error);
                  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];
          }
  
          bzero(ld->xl_tx_list, XL_TX_LIST_SZ);
          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;
  
          bus_dmamap_sync(ld->xl_tx_tag, ld->xl_tx_dmamap, BUS_DMASYNC_PREWRITE);
          return (0);
  }
  
  /*
   * Initialize the RX descriptors and allocate mbufs for them. Note that
   * we arrange the descriptors in a closed ring, so that the last descriptor
   * points back to the first.
   */
  static int
  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;
  
          XL_LOCK_ASSERT(sc);
  
          cd = &sc->xl_cdata;
          ld = &sc->xl_ldata;
  
          for (i = 0; i < XL_RX_LIST_CNT; i++) {
                  cd->xl_rx_chain[i].xl_ptr = &ld->xl_rx_list[i];
                  error = bus_dmamap_create(sc->xl_mtag, 0,
                      &cd->xl_rx_chain[i].xl_map);
                  if (error)
                          return (error);
                  error = xl_newbuf(sc, &cd->xl_rx_chain[i]);
                  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);
          }
  
          bus_dmamap_sync(ld->xl_rx_tag, ld->xl_rx_dmamap, BUS_DMASYNC_PREWRITE);
          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)
  {
          struct mbuf             *m_new = NULL;
          bus_dmamap_t            map;
          bus_dma_segment_t       segs[1];
          int                     error, nseg;
  
          XL_LOCK_ASSERT(sc);
  
          m_new = m_getcl(M_NOWAIT, 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_sg(sc->xl_mtag, sc->xl_tmpmap, m_new,
              segs, &nseg, BUS_DMA_NOWAIT);
          if (error) {
                  m_freem(m_new);
                  device_printf(sc->xl_dev, "can't map mbuf (error %d)\n",
                      error);
                  return (error);
          }
          KASSERT(nseg == 1,
              ("%s: too many DMA segments (%d)", __func__, nseg));
  
          bus_dmamap_unload(sc->xl_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(m_new->m_len | XL_LAST_FRAG);
          c->xl_ptr->xl_frag.xl_addr = htole32(segs->ds_addr);
          c->xl_ptr->xl_status = 0;
          bus_dmamap_sync(sc->xl_mtag, c->xl_map, BUS_DMASYNC_PREREAD);
          return (0);
  }
  
  static int
  xl_rx_resync(struct xl_softc *sc)
  {
          struct xl_chain_onefrag *pos;
          int                     i;
  
          XL_LOCK_ASSERT(sc);
  
          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 int
  xl_rxeof(struct xl_softc *sc)
  {
          struct mbuf             *m;
          struct ifnet            *ifp = sc->xl_ifp;
          struct xl_chain_onefrag *cur_rx;
          int                     total_len;
          int                     rx_npkts = 0;
          u_int32_t               rxstat;
  
          XL_LOCK_ASSERT(sc);
  again:
          bus_dmamap_sync(sc->xl_ldata.xl_rx_tag, sc->xl_ldata.xl_rx_dmamap,
              BUS_DMASYNC_POSTREAD);
          while ((rxstat = le32toh(sc->xl_cdata.xl_rx_head->xl_ptr->xl_status))) {
  #ifdef DEVICE_POLLING
                  if (ifp->if_capenable & IFCAP_POLLING) {
                          if (sc->rxcycles <= 0)
                                  break;
                          sc->rxcycles--;
                  }
  #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;
                  rx_npkts++;
  
                  /*
                   * 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;
                          bus_dmamap_sync(sc->xl_ldata.xl_rx_tag,
                              sc->xl_ldata.xl_rx_dmamap, BUS_DMASYNC_PREWRITE);
                          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)) {
                          device_printf(sc->xl_dev,
                              "bad receive status -- packet dropped\n");
                          ifp->if_ierrors++;
                          cur_rx->xl_ptr->xl_status = 0;
                          bus_dmamap_sync(sc->xl_ldata.xl_rx_tag,
                              sc->xl_ldata.xl_rx_dmamap, BUS_DMASYNC_PREWRITE);
                          continue;
                  }
  
                  /* No errors; receive the packet. */
                  bus_dmamap_sync(sc->xl_mtag, cur_rx->xl_map,
                      BUS_DMASYNC_POSTREAD);
                  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)) {
                          ifp->if_ierrors++;
                          cur_rx->xl_ptr->xl_status = 0;
                          bus_dmamap_sync(sc->xl_ldata.xl_rx_tag,
                              sc->xl_ldata.xl_rx_dmamap, BUS_DMASYNC_PREWRITE);
                          continue;
                  }
                  bus_dmamap_sync(sc->xl_ldata.xl_rx_tag,
                      sc->xl_ldata.xl_rx_dmamap, BUS_DMASYNC_PREWRITE);
  
                  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;
                                  m->m_pkthdr.csum_data = 0xffff;
                          }
                  }
  
                  XL_UNLOCK(sc);
                  (*ifp->if_input)(ifp, m);
                  XL_LOCK(sc);
  
                  /*
                   * If we are running from the taskqueue, the interface
                   * might have been stopped while we were passing the last
                   * packet up the network stack.
                   */
                  if (!(ifp->if_drv_flags & IFF_DRV_RUNNING))
                          return (rx_npkts);
          }
  
          /*
           * 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;
          }
          return (rx_npkts);
  }
  
  /*
   * Taskqueue wrapper for xl_rxeof().
   */
  static void
  xl_rxeof_task(void *arg, int pending)
  {
          struct xl_softc *sc = (struct xl_softc *)arg;
  
          XL_LOCK(sc);
          if (sc->xl_ifp->if_drv_flags & IFF_DRV_RUNNING)
                  xl_rxeof(sc);
          XL_UNLOCK(sc);
  }
  
  /*
   * 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 = sc->xl_ifp;
  
          XL_LOCK_ASSERT(sc);
  
          /*
           * 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_sync(sc->xl_mtag, cur_tx->xl_map,
                      BUS_DMASYNC_POSTWRITE);
                  bus_dmamap_unload(sc->xl_mtag, cur_tx->xl_map);
                  m_freem(cur_tx->xl_mbuf);
                  cur_tx->xl_mbuf = NULL;
                  ifp->if_opackets++;
                  ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
  
                  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) {
                  sc->xl_wdog_timer = 0;
                  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);
                  }
          }
  }
  
  static void
  xl_txeof_90xB(struct xl_softc *sc)
  {
          struct xl_chain         *cur_tx = NULL;
          struct ifnet            *ifp = sc->xl_ifp;
          int                     idx;
  
          XL_LOCK_ASSERT(sc);
  
          bus_dmamap_sync(sc->xl_ldata.xl_tx_tag, sc->xl_ldata.xl_tx_dmamap,
              BUS_DMASYNC_POSTREAD);
          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_sync(sc->xl_mtag, cur_tx->xl_map,
                              BUS_DMASYNC_POSTWRITE);
                          bus_dmamap_unload(sc->xl_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);
          }
  
          if (sc->xl_cdata.xl_tx_cnt == 0)
                  sc->xl_wdog_timer = 0;
          sc->xl_cdata.xl_tx_cons = idx;
  
          if (cur_tx != NULL)
                  ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
  }
  
  /*
   * 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)
  {
          u_int8_t                txstat;
  
          XL_LOCK_ASSERT(sc);
  
          while ((txstat = CSR_READ_1(sc, XL_TX_STATUS))) {
                  if (txstat & XL_TXSTATUS_UNDERRUN ||
                          txstat & XL_TXSTATUS_JABBER ||
                          txstat & XL_TXSTATUS_RECLAIM) {
                          device_printf(sc->xl_dev,
                              "transmission error: 0x%02x\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);
                                          sc->xl_wdog_timer = 5;
                                  }
                          } else {
                                  if (sc->xl_cdata.xl_tx_head != NULL) {
                                          CSR_WRITE_4(sc, XL_DOWNLIST_PTR,
                                              sc->xl_cdata.xl_tx_head->xl_phys);
                                          sc->xl_wdog_timer = 5;
                                  }
                          }
                          /*
                           * 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;
                                  device_printf(sc->xl_dev,
  "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);
          }
  }
  
  static void
  xl_intr(void *arg)
  {
          struct xl_softc         *sc = arg;
          struct ifnet            *ifp = sc->xl_ifp;
          u_int16_t               status;
  
          XL_LOCK(sc);
  
  #ifdef DEVICE_POLLING
          if (ifp->if_capenable & IFCAP_POLLING) {
                  XL_UNLOCK(sc);
                  return;
          }
  #endif
  
          for (;;) {
                  status = CSR_READ_2(sc, XL_STATUS);
                  if ((status & XL_INTRS) == 0 || status == 0xFFFF)
                          break;
                  CSR_WRITE_2(sc, XL_COMMAND,
                      XL_CMD_INTR_ACK|(status & XL_INTRS));
                  if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0)
                          break;
  
                  if (status & XL_STAT_UP_COMPLETE) {
                          if (xl_rxeof(sc) == 0) {
                                  while (xl_rx_resync(sc))
                                          xl_rxeof(sc);
                          }
                  }
  
                  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) {
                          ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
                          xl_init_locked(sc);
                          break;
                  }
  
                  if (status & XL_STAT_STATSOFLOW)
                          xl_stats_update(sc);
          }
  
          if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd) &&
              ifp->if_drv_flags & IFF_DRV_RUNNING) {
                  if (sc->xl_type == XL_TYPE_905B)
                          xl_start_90xB_locked(ifp);
                  else
                          xl_start_locked(ifp);
          }
  
          XL_UNLOCK(sc);
  }
  
  #ifdef DEVICE_POLLING
  static int
  xl_poll(struct ifnet *ifp, enum poll_cmd cmd, int count)
  {
          struct xl_softc *sc = ifp->if_softc;
          int rx_npkts = 0;
  
          XL_LOCK(sc);
          if (ifp->if_drv_flags & IFF_DRV_RUNNING)
                  rx_npkts = xl_poll_locked(ifp, cmd, count);
          XL_UNLOCK(sc);
          return (rx_npkts);
  }
  
  static int
  xl_poll_locked(struct ifnet *ifp, enum poll_cmd cmd, int count)
  {
          struct xl_softc *sc = ifp->if_softc;
          int rx_npkts;
  
          XL_LOCK_ASSERT(sc);
  
          sc->rxcycles = count;
          rx_npkts = xl_rxeof(sc);
          if (sc->xl_type == XL_TYPE_905B)
                  xl_txeof_90xB(sc);
          else
                  xl_txeof(sc);
  
          if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd)) {
                  if (sc->xl_type == XL_TYPE_905B)
                          xl_start_90xB_locked(ifp);
                  else
                          xl_start_locked(ifp);
          }
  
          if (cmd == POLL_AND_CHECK_STATUS) {
                  u_int16_t status;
  
                  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) {
                                  ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
                                  xl_init_locked(sc);
                          }
  
                          if (status & XL_STAT_STATSOFLOW)
                                  xl_stats_update(sc);
                  }
          }
          return (rx_npkts);
  }
  #endif /* DEVICE_POLLING */
  
  static void
  xl_tick(void *xsc)
  {
          struct xl_softc *sc = xsc;
          struct mii_data *mii;
  
          XL_LOCK_ASSERT(sc);
  
          if (sc->xl_miibus != NULL) {
                  mii = device_get_softc(sc->xl_miibus);
                  mii_tick(mii);
          }
  
          xl_stats_update(sc);
          if (xl_watchdog(sc) == EJUSTRETURN)
                  return;
  
          callout_reset(&sc->xl_tick_callout, hz, xl_tick, sc);
  }
  
  static void
  xl_stats_update(struct xl_softc *sc)
  {
          struct ifnet            *ifp = sc->xl_ifp;
          struct xl_stats         xl_stats;
          u_int8_t                *p;
          int                     i;
  
          XL_LOCK_ASSERT(sc);
  
          bzero((char *)&xl_stats, sizeof(struct xl_stats));
  
          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);
          XL_SEL_WIN(7);
  }
  
  /*
   * 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)
  {
          struct mbuf             *m_new;
          struct ifnet            *ifp = sc->xl_ifp;
          int                     error, i, nseg, total_len;
          u_int32_t               status;
  
          XL_LOCK_ASSERT(sc);
  
          error = bus_dmamap_load_mbuf_sg(sc->xl_mtag, c->xl_map, *m_head,
              sc->xl_cdata.xl_tx_segs, &nseg, BUS_DMA_NOWAIT);
  
          if (error && error != EFBIG) {
                  if_printf(ifp, "can't map mbuf (error %d)\n", error);
                  return (error);
          }
  
          /*
           * Handle special case: we used up all 63 fragments,
           * but we have more mbufs left in the chain. Copy the
           * data into an mbuf cluster. Note that we don't
           * bother clearing the values in the other fragment
           * pointers/counters; it wouldn't gain us anything,
           * and would waste cycles.
           */
          if (error) {
                  m_new = m_collapse(*m_head, M_NOWAIT, XL_MAXFRAGS);
                  if (m_new == NULL) {
                          m_freem(*m_head);
                          *m_head = NULL;
                          return (ENOBUFS);
                  }
                  *m_head = m_new;
  
                  error = bus_dmamap_load_mbuf_sg(sc->xl_mtag, c->xl_map,
                      *m_head, sc->xl_cdata.xl_tx_segs, &nseg, BUS_DMA_NOWAIT);
                  if (error) {
                          m_freem(*m_head);
                          *m_head = NULL;
                          if_printf(ifp, "can't map mbuf (error %d)\n", error);
                          return (error);
                  }
          }
  
          KASSERT(nseg <= XL_MAXFRAGS,
              ("%s: too many DMA segments (%d)", __func__, nseg));
          if (nseg == 0) {
                  m_freem(*m_head);
                  *m_head = NULL;
                  return (EIO);
          }
          bus_dmamap_sync(sc->xl_mtag, c->xl_map, BUS_DMASYNC_PREWRITE);
  
          total_len = 0;
          for (i = 0; i < nseg; i++) {
                  KASSERT(sc->xl_cdata.xl_tx_segs[i].ds_len <= MCLBYTES,
                      ("segment size too large"));
                  c->xl_ptr->xl_frag[i].xl_addr =
                      htole32(sc->xl_cdata.xl_tx_segs[i].ds_addr);
                  c->xl_ptr->xl_frag[i].xl_len =
                      htole32(sc->xl_cdata.xl_tx_segs[i].ds_len);
                  total_len += sc->xl_cdata.xl_tx_segs[i].ds_len;
          }
          c->xl_ptr->xl_frag[nseg - 1].xl_len |= htole32(XL_LAST_FRAG);
  
          if (sc->xl_type == XL_TYPE_905B) {
                  status = XL_TXSTAT_RND_DEFEAT;
  
  #ifndef XL905B_TXCSUM_BROKEN
                  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;
                  }
  #endif
          } else
                  status = total_len;
          c->xl_ptr->xl_status = htole32(status);
          c->xl_ptr->xl_next = 0;
  
          c->xl_mbuf = *m_head;
          return (0);
  }
  
  /*
   * Main transmit routine. To avoid having to do mbuf copies, we put pointers
   * to the mbuf data regions directly in the transmit lists. We also save a
   * copy of the pointers since the transmit list fragment pointers are
   * physical addresses.
   */
  
  static void
  xl_start(struct ifnet *ifp)
  {
          struct xl_softc         *sc = ifp->if_softc;
  
          XL_LOCK(sc);
  
          if (sc->xl_type == XL_TYPE_905B)
                  xl_start_90xB_locked(ifp);
          else
                  xl_start_locked(ifp);
  
          XL_UNLOCK(sc);
  }
  
  static void
  xl_start_locked(struct ifnet *ifp)
  {
          struct xl_softc         *sc = ifp->if_softc;
          struct mbuf             *m_head;
          struct xl_chain         *prev = NULL, *cur_tx = NULL, *start_tx;
          struct xl_chain         *prev_tx;
          int                     error;
  
          XL_LOCK_ASSERT(sc);
  
          if ((ifp->if_drv_flags & (IFF_DRV_RUNNING | IFF_DRV_OACTIVE)) !=
              IFF_DRV_RUNNING)
                  return;
          /*
           * 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_drv_flags |= IFF_DRV_OACTIVE;
                          return;
                  }
          }
  
          start_tx = sc->xl_cdata.xl_tx_free;
  
          for (; !IFQ_DRV_IS_EMPTY(&ifp->if_snd) &&
              sc->xl_cdata.xl_tx_free != NULL;) {
                  IFQ_DRV_DEQUEUE(&ifp->if_snd, m_head);
                  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;
                          if (m_head == NULL)
                                  break;
                          ifp->if_drv_flags |= IFF_DRV_OACTIVE;
                          IFQ_DRV_PREPEND(&ifp->if_snd, m_head);
                          break;
                  }
  
                  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;
  
                  /*
                   * If there's a BPF listener, bounce a copy of this frame
                   * to him.
                   */
                  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 interrupt once for the whole chain rather than
           * once for each packet.
           */
          cur_tx->xl_ptr->xl_status |= htole32(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);
                  sc->xl_cdata.xl_tx_tail->xl_ptr->xl_status &=
                      htole32(~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;
          }
          bus_dmamap_sync(sc->xl_ldata.xl_tx_tag, sc->xl_ldata.xl_tx_dmamap,
              BUS_DMASYNC_PREWRITE);
          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.
           */
          sc->xl_wdog_timer = 5;
  
          /*
           * 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. :)
           */
          taskqueue_enqueue(taskqueue_swi, &sc->xl_task);
  }
  
  static void
  xl_start_90xB_locked(struct ifnet *ifp)
  {
          struct xl_softc         *sc = ifp->if_softc;
          struct mbuf             *m_head;
          struct xl_chain         *prev = NULL, *cur_tx = NULL, *start_tx;
          struct xl_chain         *prev_tx;
          int                     error, idx;
  
          XL_LOCK_ASSERT(sc);
  
          if ((ifp->if_drv_flags & (IFF_DRV_RUNNING | IFF_DRV_OACTIVE)) !=
              IFF_DRV_RUNNING)
                  return;
  
          idx = sc->xl_cdata.xl_tx_prod;
          start_tx = &sc->xl_cdata.xl_tx_chain[idx];
  
          for (; !IFQ_DRV_IS_EMPTY(&ifp->if_snd) &&
              sc->xl_cdata.xl_tx_chain[idx].xl_mbuf == NULL;) {
                  if ((XL_TX_LIST_CNT - sc->xl_cdata.xl_tx_cnt) < 3) {
                          ifp->if_drv_flags |= IFF_DRV_OACTIVE;
                          break;
                  }
  
                  IFQ_DRV_DEQUEUE(&ifp->if_snd, m_head);
                  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;
                          if (m_head == NULL)
                                  break;
                          ifp->if_drv_flags |= IFF_DRV_OACTIVE;
                          IFQ_DRV_PREPEND(&ifp->if_snd, m_head);
                          break;
                  }
  
                  /* Chain it together. */
                  if (prev != NULL)
                          prev->xl_ptr->xl_next = htole32(cur_tx->xl_phys);
                  prev = cur_tx;
  
                  /*
                   * If there's a BPF listener, bounce a copy of this frame
                   * to him.
                   */
                  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 interrupt once for the whole chain rather than
           * once for each packet.
           */
          cur_tx->xl_ptr->xl_status |= htole32(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);
          bus_dmamap_sync(sc->xl_ldata.xl_tx_tag, sc->xl_ldata.xl_tx_dmamap,
              BUS_DMASYNC_PREWRITE);
  
          /*
           * Set a timeout in case the chip goes out to lunch.
           */
          sc->xl_wdog_timer = 5;
  }
  
  static void
  xl_init(void *xsc)
  {
          struct xl_softc         *sc = xsc;
  
          XL_LOCK(sc);
          xl_init_locked(sc);
          XL_UNLOCK(sc);
  }
  
  static void
  xl_init_locked(struct xl_softc *sc)
  {
          struct ifnet            *ifp = sc->xl_ifp;
          int                     error, i;
          struct mii_data         *mii = NULL;
  
          XL_LOCK_ASSERT(sc);
  
          if ((ifp->if_drv_flags & IFF_DRV_RUNNING) != 0)
                  return;
          /*
           * Cancel pending I/O and free all RX/TX buffers.
           */
          xl_stop(sc);
  
          /* Reset the chip to a known state. */
          xl_reset(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);
  
          /*
           * Clear WOL status and disable all WOL feature as WOL
           * would interfere Rx operation under normal environments.
           */
          if ((sc->xl_flags & XL_FLAG_WOL) != 0) {
                  XL_SEL_WIN(7);
                  CSR_READ_2(sc, XL_W7_BM_PME);
                  CSR_WRITE_2(sc, XL_W7_BM_PME, 0);
          }
          /* 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,
                                  IF_LLADDR(sc->xl_ifp)[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) {
                  device_printf(sc->xl_dev, "initialization of the rx ring failed (%d)\n",
                      error);
                  xl_stop(sc);
                  return;
          }
  
          /* Init TX descriptors. */
          if (sc->xl_type == XL_TYPE_905B)
                  error = xl_list_tx_init_90xB(sc);
          else
                  error = xl_list_tx_init(sc);
          if (error) {
                  device_printf(sc->xl_dev, "initialization of the tx ring failed (%d)\n",
                      error);
                  xl_stop(sc);
                  return;
          }
  
          /*
           * 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. */
          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_rxfilter(sc);
  
          /*
           * 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 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);
          xl_stats_update(sc);
          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_INTR_ACK|0xFF);
          CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_STAT_ENB|XL_INTRS);
  #ifdef DEVICE_POLLING
          /* Disable interrupts if we are polling. */
          if (ifp->if_capenable & IFCAP_POLLING)
                  CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|0);
          else
  #endif
          CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|XL_INTRS);
          if (sc->xl_flags & XL_FLAG_FUNCREG)
              bus_space_write_4(sc->xl_ftag, sc->xl_fhandle, 4, 0x8000);
  
          /* Set the RX early threshold */
          CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_SET_THRESH|(XL_PACKET_SIZE >>2));
          CSR_WRITE_4(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);
  
          /* XXX Downcall to miibus. */
          if (mii != NULL)
                  mii_mediachg(mii);
  
          /* Select window 7 for normal operations. */
          XL_SEL_WIN(7);
  
          ifp->if_drv_flags |= IFF_DRV_RUNNING;
          ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
  
          sc->xl_wdog_timer = 0;
          callout_reset(&sc->xl_tick_callout, hz, xl_tick, sc);
  }
  
  /*
   * Set media options.
   */
  static int
  xl_ifmedia_upd(struct ifnet *ifp)
  {
          struct xl_softc         *sc = ifp->if_softc;
          struct ifmedia          *ifm = NULL;
          struct mii_data         *mii = NULL;
  
          XL_LOCK(sc);
  
          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);
                  XL_UNLOCK(sc);
                  return (0);
          }
  
          if (sc->xl_media & XL_MEDIAOPT_MII ||
              sc->xl_media & XL_MEDIAOPT_BTX ||
              sc->xl_media & XL_MEDIAOPT_BT4) {
                  ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
                  xl_init_locked(sc);
          } else {
                  xl_setmode(sc, ifm->ifm_media);
          }
  
          XL_UNLOCK(sc);
  
          return (0);
  }
  
  /*
   * Report current media status.
   */
  static void
  xl_ifmedia_sts(struct ifnet *ifp, struct ifmediareq *ifmr)
  {
          struct xl_softc         *sc = ifp->if_softc;
          u_int32_t               icfg;
          u_int16_t               status = 0;
          struct mii_data         *mii = NULL;
  
          XL_LOCK(sc);
  
          if (sc->xl_miibus != NULL)
                  mii = device_get_softc(sc->xl_miibus);
  
          XL_SEL_WIN(4);
          status = CSR_READ_2(sc, XL_W4_MEDIA_STATUS);
  
          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;
          ifmr->ifm_status = IFM_AVALID;
  
          if ((status & XL_MEDIASTAT_CARRIER) == 0)
                  ifmr->ifm_status |= IFM_ACTIVE;
  
          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;
          }
  
          XL_UNLOCK(sc);
  }
  
  static int
  xl_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
  {
          struct xl_softc         *sc = ifp->if_softc;
          struct ifreq            *ifr = (struct ifreq *) data;
          int                     error = 0, mask;
          struct mii_data         *mii = NULL;
  
          switch (command) {
          case SIOCSIFFLAGS:
                  XL_LOCK(sc);
                  if (ifp->if_flags & IFF_UP) {
                          if (ifp->if_drv_flags & IFF_DRV_RUNNING &&
                              (ifp->if_flags ^ sc->xl_if_flags) &
                              (IFF_PROMISC | IFF_ALLMULTI))
                                  xl_rxfilter(sc);
                          else
                                  xl_init_locked(sc);
                  } else {
                          if (ifp->if_drv_flags & IFF_DRV_RUNNING)
                                  xl_stop(sc);
                  }
                  sc->xl_if_flags = ifp->if_flags;
                  XL_UNLOCK(sc);
                  break;
          case SIOCADDMULTI:
          case SIOCDELMULTI:
                  /* XXX Downcall from if_addmulti() possibly with locks held. */
                  XL_LOCK(sc);
                  if (ifp->if_drv_flags & IFF_DRV_RUNNING)
                          xl_rxfilter(sc);
                  XL_UNLOCK(sc);
                  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:
                  mask = ifr->ifr_reqcap ^ ifp->if_capenable;
  #ifdef DEVICE_POLLING
                  if ((mask & IFCAP_POLLING) != 0 &&
                      (ifp->if_capabilities & IFCAP_POLLING) != 0) {
                          ifp->if_capenable ^= IFCAP_POLLING;
                          if ((ifp->if_capenable & IFCAP_POLLING) != 0) {
                                  error = ether_poll_register(xl_poll, ifp);
                                  if (error)
                                          break;
                                  XL_LOCK(sc);
                                  /* Disable interrupts */
                                  CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_INTR_ENB|0);
                                  ifp->if_capenable |= IFCAP_POLLING;
                                  XL_UNLOCK(sc);
                          } else {
                                  error = ether_poll_deregister(ifp);
                                  /* Enable interrupts. */
                                  XL_LOCK(sc);
                                  CSR_WRITE_2(sc, XL_COMMAND,
                                      XL_CMD_INTR_ACK | 0xFF);
                                  CSR_WRITE_2(sc, XL_COMMAND,
                                      XL_CMD_INTR_ENB | XL_INTRS);
                                  if (sc->xl_flags & XL_FLAG_FUNCREG)
                                          bus_space_write_4(sc->xl_ftag,
                                              sc->xl_fhandle, 4, 0x8000);
                                  XL_UNLOCK(sc);
                          }
                  }
  #endif /* DEVICE_POLLING */
                  XL_LOCK(sc);
                  if ((mask & IFCAP_TXCSUM) != 0 &&
                      (ifp->if_capabilities & IFCAP_TXCSUM) != 0) {
                          ifp->if_capenable ^= IFCAP_TXCSUM;
                          if ((ifp->if_capenable & IFCAP_TXCSUM) != 0)
                                  ifp->if_hwassist |= XL905B_CSUM_FEATURES;
                          else
                                  ifp->if_hwassist &= ~XL905B_CSUM_FEATURES;
                  }
                  if ((mask & IFCAP_RXCSUM) != 0 &&
                      (ifp->if_capabilities & IFCAP_RXCSUM) != 0)
                          ifp->if_capenable ^= IFCAP_RXCSUM;
                  if ((mask & IFCAP_WOL_MAGIC) != 0 &&
                      (ifp->if_capabilities & IFCAP_WOL_MAGIC) != 0)
                          ifp->if_capenable ^= IFCAP_WOL_MAGIC;
                  XL_UNLOCK(sc);
                  break;
          default:
                  error = ether_ioctl(ifp, command, data);
                  break;
          }
  
          return (error);
  }
  
  static int
  xl_watchdog(struct xl_softc *sc)
  {
          struct ifnet            *ifp = sc->xl_ifp;
          u_int16_t               status = 0;
          int                     misintr;
  
          XL_LOCK_ASSERT(sc);
  
          if (sc->xl_wdog_timer == 0 || --sc->xl_wdog_timer != 0)
                  return (0);
  
          xl_rxeof(sc);
          xl_txeoc(sc);
          misintr = 0;
          if (sc->xl_type == XL_TYPE_905B) {
                  xl_txeof_90xB(sc);
                  if (sc->xl_cdata.xl_tx_cnt == 0)
                          misintr++;
          } else {
                  xl_txeof(sc);
                  if (sc->xl_cdata.xl_tx_head == NULL)
                          misintr++;
          }
          if (misintr != 0) {
                  device_printf(sc->xl_dev,
                      "watchdog timeout (missed Tx interrupts) -- recovering\n");
                  return (0);
          }
  
          ifp->if_oerrors++;
          XL_SEL_WIN(4);
          status = CSR_READ_2(sc, XL_W4_MEDIA_STATUS);
          device_printf(sc->xl_dev, "watchdog timeout\n");
  
          if (status & XL_MEDIASTAT_CARRIER)
                  device_printf(sc->xl_dev,
                      "no carrier - transceiver cable problem?\n");
  
          ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
          xl_init_locked(sc);
  
          if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd)) {
                  if (sc->xl_type == XL_TYPE_905B)
                          xl_start_90xB_locked(ifp);
                  else
                          xl_start_locked(ifp);
          }
  
          return (EJUSTRETURN);
  }
  
  /*
   * Stop the adapter and free any mbufs allocated to the
   * RX and TX lists.
   */
  static void
  xl_stop(struct xl_softc *sc)
  {
          register int            i;
          struct ifnet            *ifp = sc->xl_ifp;
  
          XL_LOCK_ASSERT(sc);
  
          sc->xl_wdog_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_tick_callout);
  
          /*
           * 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_mtag,
                              sc->xl_cdata.xl_rx_chain[i].xl_map);
                          bus_dmamap_destroy(sc->xl_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;
                  }
          }
          if (sc->xl_ldata.xl_rx_list != 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_mtag,
                              sc->xl_cdata.xl_tx_chain[i].xl_map);
                          bus_dmamap_destroy(sc->xl_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;
                  }
          }
          if (sc->xl_ldata.xl_tx_list != NULL)
                  bzero(sc->xl_ldata.xl_tx_list, XL_TX_LIST_SZ);
  
          ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
  }
  
  /*
   * Stop all chip I/O so that the kernel's probe routines don't
   * get confused by errant DMAs when rebooting.
   */
  static int
  xl_shutdown(device_t dev)
  {
  
          return (xl_suspend(dev));
  }
  
  static int
  xl_suspend(device_t dev)
  {
          struct xl_softc         *sc;
  
          sc = device_get_softc(dev);
  
          XL_LOCK(sc);
          xl_stop(sc);
          xl_setwol(sc);
          XL_UNLOCK(sc);
  
          return (0);
  }
  
  static int
  xl_resume(device_t dev)
  {
          struct xl_softc         *sc;
          struct ifnet            *ifp;
  
          sc = device_get_softc(dev);
          ifp = sc->xl_ifp;
  
          XL_LOCK(sc);
  
          if (ifp->if_flags & IFF_UP) {
                  ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
                  xl_init_locked(sc);
          }
  
          XL_UNLOCK(sc);
  
          return (0);
  }
  
  static void
  xl_setwol(struct xl_softc *sc)
  {
          struct ifnet            *ifp;
          u_int16_t               cfg, pmstat;
  
          if ((sc->xl_flags & XL_FLAG_WOL) == 0)
                  return;
  
          ifp = sc->xl_ifp;
          XL_SEL_WIN(7);
          /* Clear any pending PME events. */
          CSR_READ_2(sc, XL_W7_BM_PME);
          cfg = 0;
          if ((ifp->if_capenable & IFCAP_WOL_MAGIC) != 0)
                  cfg |= XL_BM_PME_MAGIC;
          CSR_WRITE_2(sc, XL_W7_BM_PME, cfg);
          /* Enable RX. */
          if ((ifp->if_capenable & IFCAP_WOL_MAGIC) != 0)
                  CSR_WRITE_2(sc, XL_COMMAND, XL_CMD_RX_ENABLE);
          /* Request PME. */
          pmstat = pci_read_config(sc->xl_dev,
              sc->xl_pmcap + PCIR_POWER_STATUS, 2);
          if ((ifp->if_capenable & IFCAP_WOL_MAGIC) != 0)
                  pmstat |= PCIM_PSTAT_PMEENABLE;
          else
                  pmstat &= ~PCIM_PSTAT_PMEENABLE;
          pci_write_config(sc->xl_dev,
              sc->xl_pmcap + PCIR_POWER_STATUS, pmstat, 2);
  }