root/sys/dev/sk/if_sk.c
/*      $OpenBSD: if_sk.c,v 2.33 2003/08/12 05:23:06 nate Exp $ */

/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 1997, 1998, 1999, 2000
 *      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.
 */
/*-
 * Copyright (c) 2003 Nathan L. Binkert <binkertn@umich.edu>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/cdefs.h>
/*
 * SysKonnect SK-NET gigabit ethernet driver for FreeBSD. Supports
 * the SK-984x series adapters, both single port and dual port.
 * References:
 *      The XaQti XMAC II datasheet,
 *  https://www.freebsd.org/~wpaul/SysKonnect/xmacii_datasheet_rev_c_9-29.pdf
 *      The SysKonnect GEnesis manual, http://www.syskonnect.com
 *
 * Note: XaQti has been acquired by Vitesse, and Vitesse does not have the
 * XMAC II datasheet online. I have put my copy at people.freebsd.org as a
 * convenience to others until Vitesse corrects this problem:
 *
 * https://people.freebsd.org/~wpaul/SysKonnect/xmacii_datasheet_rev_c_9-29.pdf
 *
 * Written by Bill Paul <wpaul@ee.columbia.edu>
 * Department of Electrical Engineering
 * Columbia University, New York City
 */
/*
 * The SysKonnect gigabit ethernet adapters consist of two main
 * components: the SysKonnect GEnesis controller chip and the XaQti Corp.
 * XMAC II gigabit ethernet MAC. The XMAC provides all of the MAC
 * components and a PHY while the GEnesis controller provides a PCI
 * interface with DMA support. Each card may have between 512K and
 * 2MB of SRAM on board depending on the configuration.
 *
 * The SysKonnect GEnesis controller can have either one or two XMAC
 * chips connected to it, allowing single or dual port NIC configurations.
 * SysKonnect has the distinction of being the only vendor on the market
 * with a dual port gigabit ethernet NIC. The GEnesis provides dual FIFOs,
 * dual DMA queues, packet/MAC/transmit arbiters and direct access to the
 * XMAC registers. This driver takes advantage of these features to allow
 * both XMACs to operate as independent interfaces.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/endian.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/queue.h>
#include <sys/sysctl.h>

#include <net/bpf.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_arp.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <net/if_types.h>
#include <net/if_vlan_var.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>

#include <machine/bus.h>
#include <machine/in_cksum.h>
#include <machine/resource.h>
#include <sys/rman.h>

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

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

#if 0
#define SK_USEIOSPACE
#endif

#include <dev/sk/if_skreg.h>
#include <dev/sk/xmaciireg.h>
#include <dev/sk/yukonreg.h>

MODULE_DEPEND(sk, pci, 1, 1, 1);
MODULE_DEPEND(sk, ether, 1, 1, 1);
MODULE_DEPEND(sk, miibus, 1, 1, 1);

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

static const struct sk_type sk_devs[] = {
        {
                VENDORID_SK,
                DEVICEID_SK_V1,
                "SysKonnect Gigabit Ethernet (V1.0)"
        },
        {
                VENDORID_SK,
                DEVICEID_SK_V2,
                "SysKonnect Gigabit Ethernet (V2.0)"
        },
        {
                VENDORID_MARVELL,
                DEVICEID_SK_V2,
                "Marvell Gigabit Ethernet"
        },
        {
                VENDORID_MARVELL,
                DEVICEID_BELKIN_5005,
                "Belkin F5D5005 Gigabit Ethernet"
        },
        {
                VENDORID_3COM,
                DEVICEID_3COM_3C940,
                "3Com 3C940 Gigabit Ethernet"
        },
        {
                VENDORID_LINKSYS,
                DEVICEID_LINKSYS_EG1032,
                "Linksys EG1032 Gigabit Ethernet"
        },
        {
                VENDORID_DLINK,
                DEVICEID_DLINK_DGE530T_A1,
                "D-Link DGE-530T Gigabit Ethernet"
        },
        {
                VENDORID_DLINK,
                DEVICEID_DLINK_DGE530T_B1,
                "D-Link DGE-530T Gigabit Ethernet"
        },
        { 0, 0, NULL }
};

static int skc_probe(device_t);
static int skc_attach(device_t);
static void skc_child_deleted(device_t, device_t);
static int skc_detach(device_t);
static int skc_shutdown(device_t);
static int skc_suspend(device_t);
static int skc_resume(device_t);
static bus_dma_tag_t skc_get_dma_tag(device_t, device_t);
static int sk_detach(device_t);
static int sk_probe(device_t);
static int sk_attach(device_t);
static void sk_tick(void *);
static void sk_yukon_tick(void *);
static void sk_intr(void *);
static void sk_intr_xmac(struct sk_if_softc *);
static void sk_intr_bcom(struct sk_if_softc *);
static void sk_intr_yukon(struct sk_if_softc *);
static __inline void sk_rxcksum(if_t, struct mbuf *, u_int32_t);
static __inline int sk_rxvalid(struct sk_softc *, u_int32_t, u_int32_t);
static void sk_rxeof(struct sk_if_softc *);
static void sk_jumbo_rxeof(struct sk_if_softc *);
static void sk_txeof(struct sk_if_softc *);
static void sk_txcksum(if_t, struct mbuf *, struct sk_tx_desc *);
static int sk_encap(struct sk_if_softc *, struct mbuf **);
static void sk_start(if_t);
static void sk_start_locked(if_t);
static int sk_ioctl(if_t, u_long, caddr_t);
static void sk_init(void *);
static void sk_init_locked(struct sk_if_softc *);
static void sk_init_xmac(struct sk_if_softc *);
static void sk_init_yukon(struct sk_if_softc *);
static void sk_stop(struct sk_if_softc *);
static void sk_watchdog(void *);
static int sk_ifmedia_upd(if_t);
static void sk_ifmedia_sts(if_t, struct ifmediareq *);
static void sk_reset(struct sk_softc *);
static __inline void sk_discard_rxbuf(struct sk_if_softc *, int);
static __inline void sk_discard_jumbo_rxbuf(struct sk_if_softc *, int);
static int sk_newbuf(struct sk_if_softc *, int);
static int sk_jumbo_newbuf(struct sk_if_softc *, int);
static void sk_dmamap_cb(void *, bus_dma_segment_t *, int, int);
static int sk_dma_alloc(struct sk_if_softc *);
static int sk_dma_jumbo_alloc(struct sk_if_softc *);
static void sk_dma_free(struct sk_if_softc *);
static void sk_dma_jumbo_free(struct sk_if_softc *);
static int sk_init_rx_ring(struct sk_if_softc *);
static int sk_init_jumbo_rx_ring(struct sk_if_softc *);
static void sk_init_tx_ring(struct sk_if_softc *);
static u_int32_t sk_win_read_4(struct sk_softc *, int);
static u_int16_t sk_win_read_2(struct sk_softc *, int);
static u_int8_t sk_win_read_1(struct sk_softc *, int);
static void sk_win_write_4(struct sk_softc *, int, u_int32_t);
static void sk_win_write_2(struct sk_softc *, int, u_int32_t);
static void sk_win_write_1(struct sk_softc *, int, u_int32_t);

static int sk_miibus_readreg(device_t, int, int);
static int sk_miibus_writereg(device_t, int, int, int);
static void sk_miibus_statchg(device_t);

static int sk_xmac_miibus_readreg(struct sk_if_softc *, int, int);
static int sk_xmac_miibus_writereg(struct sk_if_softc *, int, int,
                                                int);
static void sk_xmac_miibus_statchg(struct sk_if_softc *);

static int sk_marv_miibus_readreg(struct sk_if_softc *, int, int);
static int sk_marv_miibus_writereg(struct sk_if_softc *, int, int,
                                                int);
static void sk_marv_miibus_statchg(struct sk_if_softc *);

static uint32_t sk_xmchash(const uint8_t *);
static void sk_setfilt(struct sk_if_softc *, u_int16_t *, int);
static void sk_rxfilter(struct sk_if_softc *);
static void sk_rxfilter_genesis(struct sk_if_softc *);
static void sk_rxfilter_yukon(struct sk_if_softc *);

static int sysctl_int_range(SYSCTL_HANDLER_ARGS, int low, int high);
static int sysctl_hw_sk_int_mod(SYSCTL_HANDLER_ARGS);

/* Tunables. */
static int jumbo_disable = 0;
TUNABLE_INT("hw.skc.jumbo_disable", &jumbo_disable);

/*
 * It seems that SK-NET GENESIS supports very simple checksum offload
 * capability for Tx and I believe it can generate 0 checksum value for
 * UDP packets in Tx as the hardware can't differenciate UDP packets from
 * TCP packets. 0 chcecksum value for UDP packet is an invalid one as it
 * means sender didn't perforam checksum computation. For the safety I
 * disabled UDP checksum offload capability at the moment.
 */
#define SK_CSUM_FEATURES        (CSUM_TCP)

/*
 * Note that we have newbus methods for both the GEnesis controller
 * itself and the XMAC(s). The XMACs are children of the GEnesis, and
 * the miibus code is a child of the XMACs. We need to do it this way
 * so that the miibus drivers can access the PHY registers on the
 * right PHY. It's not quite what I had in mind, but it's the only
 * design that achieves the desired effect.
 */
static device_method_t skc_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         skc_probe),
        DEVMETHOD(device_attach,        skc_attach),
        DEVMETHOD(device_detach,        skc_detach),
        DEVMETHOD(device_suspend,       skc_suspend),
        DEVMETHOD(device_resume,        skc_resume),
        DEVMETHOD(device_shutdown,      skc_shutdown),

        DEVMETHOD(bus_child_deleted,    skc_child_deleted),
        DEVMETHOD(bus_get_dma_tag,      skc_get_dma_tag),

        DEVMETHOD_END
};

static driver_t skc_driver = {
        "skc",
        skc_methods,
        sizeof(struct sk_softc)
};

static device_method_t sk_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         sk_probe),
        DEVMETHOD(device_attach,        sk_attach),
        DEVMETHOD(device_detach,        sk_detach),
        DEVMETHOD(device_shutdown,      bus_generic_shutdown),

        /* MII interface */
        DEVMETHOD(miibus_readreg,       sk_miibus_readreg),
        DEVMETHOD(miibus_writereg,      sk_miibus_writereg),
        DEVMETHOD(miibus_statchg,       sk_miibus_statchg),

        DEVMETHOD_END
};

static driver_t sk_driver = {
        "sk",
        sk_methods,
        sizeof(struct sk_if_softc)
};

DRIVER_MODULE(skc, pci, skc_driver, NULL, NULL);
DRIVER_MODULE(sk, skc, sk_driver, NULL, NULL);
DRIVER_MODULE(miibus, sk, miibus_driver, NULL, NULL);

static struct resource_spec sk_res_spec_io[] = {
        { SYS_RES_IOPORT,       PCIR_BAR(1),    RF_ACTIVE },
        { SYS_RES_IRQ,          0,              RF_ACTIVE | RF_SHAREABLE },
        { -1,                   0,              0 }
};

static struct resource_spec sk_res_spec_mem[] = {
        { SYS_RES_MEMORY,       PCIR_BAR(0),    RF_ACTIVE },
        { SYS_RES_IRQ,          0,              RF_ACTIVE | RF_SHAREABLE },
        { -1,                   0,              0 }
};

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

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

#define SK_WIN_SETBIT_4(sc, reg, x)     \
        sk_win_write_4(sc, reg, sk_win_read_4(sc, reg) | x)

#define SK_WIN_CLRBIT_4(sc, reg, x)     \
        sk_win_write_4(sc, reg, sk_win_read_4(sc, reg) & ~x)

#define SK_WIN_SETBIT_2(sc, reg, x)     \
        sk_win_write_2(sc, reg, sk_win_read_2(sc, reg) | x)

#define SK_WIN_CLRBIT_2(sc, reg, x)     \
        sk_win_write_2(sc, reg, sk_win_read_2(sc, reg) & ~x)

static u_int32_t
sk_win_read_4(struct sk_softc *sc, int reg)
{
#ifdef SK_USEIOSPACE
        CSR_WRITE_4(sc, SK_RAP, SK_WIN(reg));
        return(CSR_READ_4(sc, SK_WIN_BASE + SK_REG(reg)));
#else
        return(CSR_READ_4(sc, reg));
#endif
}

static u_int16_t
sk_win_read_2(struct sk_softc *sc, int reg)
{
#ifdef SK_USEIOSPACE
        CSR_WRITE_4(sc, SK_RAP, SK_WIN(reg));
        return(CSR_READ_2(sc, SK_WIN_BASE + SK_REG(reg)));
#else
        return(CSR_READ_2(sc, reg));
#endif
}

static u_int8_t
sk_win_read_1(struct sk_softc *sc, int reg)
{
#ifdef SK_USEIOSPACE
        CSR_WRITE_4(sc, SK_RAP, SK_WIN(reg));
        return(CSR_READ_1(sc, SK_WIN_BASE + SK_REG(reg)));
#else
        return(CSR_READ_1(sc, reg));
#endif
}

static void
sk_win_write_4(struct sk_softc *sc, int reg, u_int32_t val)
{
#ifdef SK_USEIOSPACE
        CSR_WRITE_4(sc, SK_RAP, SK_WIN(reg));
        CSR_WRITE_4(sc, SK_WIN_BASE + SK_REG(reg), val);
#else
        CSR_WRITE_4(sc, reg, val);
#endif
        return;
}

static void
sk_win_write_2(struct sk_softc *sc, int reg, u_int32_t val)
{
#ifdef SK_USEIOSPACE
        CSR_WRITE_4(sc, SK_RAP, SK_WIN(reg));
        CSR_WRITE_2(sc, SK_WIN_BASE + SK_REG(reg), val);
#else
        CSR_WRITE_2(sc, reg, val);
#endif
        return;
}

static void
sk_win_write_1(struct sk_softc *sc, int reg, u_int32_t val)
{
#ifdef SK_USEIOSPACE
        CSR_WRITE_4(sc, SK_RAP, SK_WIN(reg));
        CSR_WRITE_1(sc, SK_WIN_BASE + SK_REG(reg), val);
#else
        CSR_WRITE_1(sc, reg, val);
#endif
        return;
}

static int
sk_miibus_readreg(device_t dev, int phy, int reg)
{
        struct sk_if_softc      *sc_if;
        int                     v;

        sc_if = device_get_softc(dev);

        SK_IF_MII_LOCK(sc_if);
        switch(sc_if->sk_softc->sk_type) {
        case SK_GENESIS:
                v = sk_xmac_miibus_readreg(sc_if, phy, reg);
                break;
        case SK_YUKON:
        case SK_YUKON_LITE:
        case SK_YUKON_LP:
                v = sk_marv_miibus_readreg(sc_if, phy, reg);
                break;
        default:
                v = 0;
                break;
        }
        SK_IF_MII_UNLOCK(sc_if);

        return (v);
}

static int
sk_miibus_writereg(device_t dev, int phy, int reg, int val)
{
        struct sk_if_softc      *sc_if;
        int                     v;

        sc_if = device_get_softc(dev);

        SK_IF_MII_LOCK(sc_if);
        switch(sc_if->sk_softc->sk_type) {
        case SK_GENESIS:
                v = sk_xmac_miibus_writereg(sc_if, phy, reg, val);
                break;
        case SK_YUKON:
        case SK_YUKON_LITE:
        case SK_YUKON_LP:
                v = sk_marv_miibus_writereg(sc_if, phy, reg, val);
                break;
        default:
                v = 0;
                break;
        }
        SK_IF_MII_UNLOCK(sc_if);

        return (v);
}

static void
sk_miibus_statchg(device_t dev)
{
        struct sk_if_softc      *sc_if;

        sc_if = device_get_softc(dev);

        SK_IF_MII_LOCK(sc_if);
        switch(sc_if->sk_softc->sk_type) {
        case SK_GENESIS:
                sk_xmac_miibus_statchg(sc_if);
                break;
        case SK_YUKON:
        case SK_YUKON_LITE:
        case SK_YUKON_LP:
                sk_marv_miibus_statchg(sc_if);
                break;
        }
        SK_IF_MII_UNLOCK(sc_if);

        return;
}

static int
sk_xmac_miibus_readreg(struct sk_if_softc *sc_if, int phy, int reg)
{
        int                     i;

        SK_XM_WRITE_2(sc_if, XM_PHY_ADDR, reg|(phy << 8));
        SK_XM_READ_2(sc_if, XM_PHY_DATA);
        if (sc_if->sk_phytype != SK_PHYTYPE_XMAC) {
                for (i = 0; i < SK_TIMEOUT; i++) {
                        DELAY(1);
                        if (SK_XM_READ_2(sc_if, XM_MMUCMD) &
                            XM_MMUCMD_PHYDATARDY)
                                break;
                }

                if (i == SK_TIMEOUT) {
                        if_printf(sc_if->sk_ifp, "phy failed to come ready\n");
                        return(0);
                }
        }
        DELAY(1);
        i = SK_XM_READ_2(sc_if, XM_PHY_DATA);

        return(i);
}

static int
sk_xmac_miibus_writereg(struct sk_if_softc *sc_if, int phy, int reg, int val)
{
        int                     i;

        SK_XM_WRITE_2(sc_if, XM_PHY_ADDR, reg|(phy << 8));
        for (i = 0; i < SK_TIMEOUT; i++) {
                if (!(SK_XM_READ_2(sc_if, XM_MMUCMD) & XM_MMUCMD_PHYBUSY))
                        break;
        }

        if (i == SK_TIMEOUT) {
                if_printf(sc_if->sk_ifp, "phy failed to come ready\n");
                return (ETIMEDOUT);
        }

        SK_XM_WRITE_2(sc_if, XM_PHY_DATA, val);
        for (i = 0; i < SK_TIMEOUT; i++) {
                DELAY(1);
                if (!(SK_XM_READ_2(sc_if, XM_MMUCMD) & XM_MMUCMD_PHYBUSY))
                        break;
        }
        if (i == SK_TIMEOUT)
                if_printf(sc_if->sk_ifp, "phy write timed out\n");

        return(0);
}

static void
sk_xmac_miibus_statchg(struct sk_if_softc *sc_if)
{
        struct mii_data         *mii;

        mii = device_get_softc(sc_if->sk_miibus);

        /*
         * If this is a GMII PHY, manually set the XMAC's
         * duplex mode accordingly.
         */
        if (sc_if->sk_phytype != SK_PHYTYPE_XMAC) {
                if ((mii->mii_media_active & IFM_GMASK) == IFM_FDX) {
                        SK_XM_SETBIT_2(sc_if, XM_MMUCMD, XM_MMUCMD_GMIIFDX);
                } else {
                        SK_XM_CLRBIT_2(sc_if, XM_MMUCMD, XM_MMUCMD_GMIIFDX);
                }
        }
}

static int
sk_marv_miibus_readreg(struct sk_if_softc *sc_if, int phy, int reg)
{
        u_int16_t               val;
        int                     i;

        if (sc_if->sk_phytype != SK_PHYTYPE_MARV_COPPER &&
            sc_if->sk_phytype != SK_PHYTYPE_MARV_FIBER) {
                return(0);
        }

        SK_YU_WRITE_2(sc_if, YUKON_SMICR, YU_SMICR_PHYAD(phy) |
                      YU_SMICR_REGAD(reg) | YU_SMICR_OP_READ);

        for (i = 0; i < SK_TIMEOUT; i++) {
                DELAY(1);
                val = SK_YU_READ_2(sc_if, YUKON_SMICR);
                if (val & YU_SMICR_READ_VALID)
                        break;
        }

        if (i == SK_TIMEOUT) {
                if_printf(sc_if->sk_ifp, "phy failed to come ready\n");
                return(0);
        }

        val = SK_YU_READ_2(sc_if, YUKON_SMIDR);

        return(val);
}

static int
sk_marv_miibus_writereg(struct sk_if_softc *sc_if, int phy, int reg, int val)
{
        int                     i;

        SK_YU_WRITE_2(sc_if, YUKON_SMIDR, val);
        SK_YU_WRITE_2(sc_if, YUKON_SMICR, YU_SMICR_PHYAD(phy) |
                      YU_SMICR_REGAD(reg) | YU_SMICR_OP_WRITE);

        for (i = 0; i < SK_TIMEOUT; i++) {
                DELAY(1);
                if ((SK_YU_READ_2(sc_if, YUKON_SMICR) & YU_SMICR_BUSY) == 0)
                        break;
        }
        if (i == SK_TIMEOUT)
                if_printf(sc_if->sk_ifp, "phy write timeout\n");

        return(0);
}

static void
sk_marv_miibus_statchg(struct sk_if_softc *sc_if)
{
        return;
}

#define HASH_BITS               6

static u_int32_t
sk_xmchash(const uint8_t *addr)
{
        uint32_t crc;

        /* Compute CRC for the address value. */
        crc = ether_crc32_le(addr, ETHER_ADDR_LEN);

        return (~crc & ((1 << HASH_BITS) - 1));
}

static void
sk_setfilt(struct sk_if_softc *sc_if, u_int16_t *addr, int slot)
{
        int                     base;

        base = XM_RXFILT_ENTRY(slot);

        SK_XM_WRITE_2(sc_if, base, addr[0]);
        SK_XM_WRITE_2(sc_if, base + 2, addr[1]);
        SK_XM_WRITE_2(sc_if, base + 4, addr[2]);

        return;
}

static void
sk_rxfilter(struct sk_if_softc *sc_if)
{
        struct sk_softc         *sc;

        SK_IF_LOCK_ASSERT(sc_if);

        sc = sc_if->sk_softc;
        if (sc->sk_type == SK_GENESIS)
                sk_rxfilter_genesis(sc_if);
        else
                sk_rxfilter_yukon(sc_if);
}

struct sk_add_maddr_genesis_ctx {
        struct sk_if_softc *sc_if;
        uint32_t hashes[2];
        uint32_t mode;
};

static u_int
sk_add_maddr_genesis(void *arg, struct sockaddr_dl *sdl, u_int cnt)
{
        struct sk_add_maddr_genesis_ctx *ctx = arg;
        int h;

        /*
         * Program the first XM_RXFILT_MAX multicast groups
         * into the perfect filter.
         */
        if (cnt + 1 < XM_RXFILT_MAX) {
                sk_setfilt(ctx->sc_if, (uint16_t *)LLADDR(sdl), cnt + 1);
                ctx->mode |= XM_MODE_RX_USE_PERFECT;
                return (1);
        }
        h = sk_xmchash((const uint8_t *)LLADDR(sdl));
        if (h < 32)
                ctx->hashes[0] |= (1 << h);
        else
                ctx->hashes[1] |= (1 << (h - 32));
        ctx->mode |= XM_MODE_RX_USE_HASH;

        return (1);
}

static void
sk_rxfilter_genesis(struct sk_if_softc *sc_if)
{
        if_t                    ifp = sc_if->sk_ifp;
        struct sk_add_maddr_genesis_ctx ctx = { sc_if, { 0, 0 } };
        int                     i;
        u_int16_t               dummy[] = { 0, 0, 0 };

        SK_IF_LOCK_ASSERT(sc_if);

        ctx.mode = SK_XM_READ_4(sc_if, XM_MODE);
        ctx.mode &= ~(XM_MODE_RX_PROMISC | XM_MODE_RX_USE_HASH |
            XM_MODE_RX_USE_PERFECT);
        /* First, zot all the existing perfect filters. */
        for (i = 1; i < XM_RXFILT_MAX; i++)
                sk_setfilt(sc_if, dummy, i);

        /* Now program new ones. */
        if (if_getflags(ifp) & IFF_ALLMULTI || if_getflags(ifp) & IFF_PROMISC) {
                if (if_getflags(ifp) & IFF_ALLMULTI)
                        ctx.mode |= XM_MODE_RX_USE_HASH;
                if (if_getflags(ifp) & IFF_PROMISC)
                        ctx.mode |= XM_MODE_RX_PROMISC;
                ctx.hashes[0] = 0xFFFFFFFF;
                ctx.hashes[1] = 0xFFFFFFFF;
        } else
                /* XXX want to maintain reverse semantics */
                if_foreach_llmaddr(ifp, sk_add_maddr_genesis, &ctx);

        SK_XM_WRITE_4(sc_if, XM_MODE, ctx.mode);
        SK_XM_WRITE_4(sc_if, XM_MAR0, ctx.hashes[0]);
        SK_XM_WRITE_4(sc_if, XM_MAR2, ctx.hashes[1]);
}

static u_int
sk_hash_maddr_yukon(void *arg, struct sockaddr_dl *sdl, u_int cnt)
{
        uint32_t crc, *hashes = arg;

        crc = ether_crc32_be(LLADDR(sdl), ETHER_ADDR_LEN);
        /* Just want the 6 least significant bits. */
        crc &= 0x3f;
        /* Set the corresponding bit in the hash table. */
        hashes[crc >> 5] |= 1 << (crc & 0x1f);

        return (1);
}

static void
sk_rxfilter_yukon(struct sk_if_softc *sc_if)
{
        if_t                    ifp;
        uint32_t                hashes[2] = { 0, 0 }, mode;

        SK_IF_LOCK_ASSERT(sc_if);

        ifp = sc_if->sk_ifp;
        mode = SK_YU_READ_2(sc_if, YUKON_RCR);
        if (if_getflags(ifp) & IFF_PROMISC)
                mode &= ~(YU_RCR_UFLEN | YU_RCR_MUFLEN); 
        else if (if_getflags(ifp) & IFF_ALLMULTI) {
                mode |= YU_RCR_UFLEN | YU_RCR_MUFLEN; 
                hashes[0] = 0xFFFFFFFF;
                hashes[1] = 0xFFFFFFFF;
        } else {
                mode |= YU_RCR_UFLEN;
                if_foreach_llmaddr(ifp, sk_hash_maddr_yukon, hashes);
                if (hashes[0] != 0 || hashes[1] != 0)
                        mode |= YU_RCR_MUFLEN;
        }

        SK_YU_WRITE_2(sc_if, YUKON_MCAH1, hashes[0] & 0xffff);
        SK_YU_WRITE_2(sc_if, YUKON_MCAH2, (hashes[0] >> 16) & 0xffff);
        SK_YU_WRITE_2(sc_if, YUKON_MCAH3, hashes[1] & 0xffff);
        SK_YU_WRITE_2(sc_if, YUKON_MCAH4, (hashes[1] >> 16) & 0xffff);
        SK_YU_WRITE_2(sc_if, YUKON_RCR, mode);
}

static int
sk_init_rx_ring(struct sk_if_softc *sc_if)
{
        struct sk_ring_data     *rd;
        bus_addr_t              addr;
        u_int32_t               csum_start;
        int                     i;

        sc_if->sk_cdata.sk_rx_cons = 0;

        csum_start = (ETHER_HDR_LEN + sizeof(struct ip))  << 16 |
            ETHER_HDR_LEN;
        rd = &sc_if->sk_rdata;
        bzero(rd->sk_rx_ring, sizeof(struct sk_rx_desc) * SK_RX_RING_CNT);
        for (i = 0; i < SK_RX_RING_CNT; i++) {
                if (sk_newbuf(sc_if, i) != 0)
                        return (ENOBUFS);
                if (i == (SK_RX_RING_CNT - 1))
                        addr = SK_RX_RING_ADDR(sc_if, 0);
                else
                        addr = SK_RX_RING_ADDR(sc_if, i + 1);
                rd->sk_rx_ring[i].sk_next = htole32(SK_ADDR_LO(addr));
                rd->sk_rx_ring[i].sk_csum_start = htole32(csum_start);
        }

        bus_dmamap_sync(sc_if->sk_cdata.sk_rx_ring_tag,
            sc_if->sk_cdata.sk_rx_ring_map,
            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);

        return(0);
}

static int
sk_init_jumbo_rx_ring(struct sk_if_softc *sc_if)
{
        struct sk_ring_data     *rd;
        bus_addr_t              addr;
        u_int32_t               csum_start;
        int                     i;

        sc_if->sk_cdata.sk_jumbo_rx_cons = 0;

        csum_start = ((ETHER_HDR_LEN + sizeof(struct ip)) << 16) |
            ETHER_HDR_LEN;
        rd = &sc_if->sk_rdata;
        bzero(rd->sk_jumbo_rx_ring,
            sizeof(struct sk_rx_desc) * SK_JUMBO_RX_RING_CNT);
        for (i = 0; i < SK_JUMBO_RX_RING_CNT; i++) {
                if (sk_jumbo_newbuf(sc_if, i) != 0)
                        return (ENOBUFS);
                if (i == (SK_JUMBO_RX_RING_CNT - 1))
                        addr = SK_JUMBO_RX_RING_ADDR(sc_if, 0);
                else
                        addr = SK_JUMBO_RX_RING_ADDR(sc_if, i + 1);
                rd->sk_jumbo_rx_ring[i].sk_next = htole32(SK_ADDR_LO(addr));
                rd->sk_jumbo_rx_ring[i].sk_csum_start = htole32(csum_start);
        }

        bus_dmamap_sync(sc_if->sk_cdata.sk_jumbo_rx_ring_tag,
            sc_if->sk_cdata.sk_jumbo_rx_ring_map,
            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);

        return (0);
}

static void
sk_init_tx_ring(struct sk_if_softc *sc_if)
{
        struct sk_ring_data     *rd;
        struct sk_txdesc        *txd;
        bus_addr_t              addr;
        int                     i;

        STAILQ_INIT(&sc_if->sk_cdata.sk_txfreeq);
        STAILQ_INIT(&sc_if->sk_cdata.sk_txbusyq);

        sc_if->sk_cdata.sk_tx_prod = 0;
        sc_if->sk_cdata.sk_tx_cons = 0;
        sc_if->sk_cdata.sk_tx_cnt = 0;

        rd = &sc_if->sk_rdata;
        bzero(rd->sk_tx_ring, sizeof(struct sk_tx_desc) * SK_TX_RING_CNT);
        for (i = 0; i < SK_TX_RING_CNT; i++) {
                if (i == (SK_TX_RING_CNT - 1))
                        addr = SK_TX_RING_ADDR(sc_if, 0);
                else
                        addr = SK_TX_RING_ADDR(sc_if, i + 1);
                rd->sk_tx_ring[i].sk_next = htole32(SK_ADDR_LO(addr));
                txd = &sc_if->sk_cdata.sk_txdesc[i];
                STAILQ_INSERT_TAIL(&sc_if->sk_cdata.sk_txfreeq, txd, tx_q);
        }

        bus_dmamap_sync(sc_if->sk_cdata.sk_tx_ring_tag,
            sc_if->sk_cdata.sk_tx_ring_map,
            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
}

static __inline void
sk_discard_rxbuf(struct sk_if_softc *sc_if, int idx)
{
        struct sk_rx_desc       *r;
        struct sk_rxdesc        *rxd;
        struct mbuf             *m;

        r = &sc_if->sk_rdata.sk_rx_ring[idx];
        rxd = &sc_if->sk_cdata.sk_rxdesc[idx];
        m = rxd->rx_m;
        r->sk_ctl = htole32(m->m_len | SK_RXSTAT | SK_OPCODE_CSUM);
}

static __inline void
sk_discard_jumbo_rxbuf(struct sk_if_softc *sc_if, int idx)
{
        struct sk_rx_desc       *r;
        struct sk_rxdesc        *rxd;
        struct mbuf             *m;

        r = &sc_if->sk_rdata.sk_jumbo_rx_ring[idx];
        rxd = &sc_if->sk_cdata.sk_jumbo_rxdesc[idx];
        m = rxd->rx_m;
        r->sk_ctl = htole32(m->m_len | SK_RXSTAT | SK_OPCODE_CSUM);
}

static int
sk_newbuf(struct sk_if_softc *sc_if, int idx)
{
        struct sk_rx_desc       *r;
        struct sk_rxdesc        *rxd;
        struct mbuf             *m;
        bus_dma_segment_t       segs[1];
        bus_dmamap_t            map;
        int                     nsegs;

        m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
        if (m == NULL)
                return (ENOBUFS);
        m->m_len = m->m_pkthdr.len = MCLBYTES;
        m_adj(m, ETHER_ALIGN);

        if (bus_dmamap_load_mbuf_sg(sc_if->sk_cdata.sk_rx_tag,
            sc_if->sk_cdata.sk_rx_sparemap, m, segs, &nsegs, 0) != 0) {
                m_freem(m);
                return (ENOBUFS);
        }
        KASSERT(nsegs == 1, ("%s: %d segments returned!", __func__, nsegs));

        rxd = &sc_if->sk_cdata.sk_rxdesc[idx];
        if (rxd->rx_m != NULL) {
                bus_dmamap_sync(sc_if->sk_cdata.sk_rx_tag, rxd->rx_dmamap,
                    BUS_DMASYNC_POSTREAD);
                bus_dmamap_unload(sc_if->sk_cdata.sk_rx_tag, rxd->rx_dmamap);
        }
        map = rxd->rx_dmamap;
        rxd->rx_dmamap = sc_if->sk_cdata.sk_rx_sparemap;
        sc_if->sk_cdata.sk_rx_sparemap = map;
        bus_dmamap_sync(sc_if->sk_cdata.sk_rx_tag, rxd->rx_dmamap,
            BUS_DMASYNC_PREREAD);
        rxd->rx_m = m;
        r = &sc_if->sk_rdata.sk_rx_ring[idx];
        r->sk_data_lo = htole32(SK_ADDR_LO(segs[0].ds_addr));
        r->sk_data_hi = htole32(SK_ADDR_HI(segs[0].ds_addr));
        r->sk_ctl = htole32(segs[0].ds_len | SK_RXSTAT | SK_OPCODE_CSUM);

        return (0);
}

static int
sk_jumbo_newbuf(struct sk_if_softc *sc_if, int idx)
{
        struct sk_rx_desc       *r;
        struct sk_rxdesc        *rxd;
        struct mbuf             *m;
        bus_dma_segment_t       segs[1];
        bus_dmamap_t            map;
        int                     nsegs;

        m = m_getjcl(M_NOWAIT, MT_DATA, M_PKTHDR, MJUM9BYTES);
        if (m == NULL)
                return (ENOBUFS);
        m->m_pkthdr.len = m->m_len = MJUM9BYTES;
        /*
         * Adjust alignment so packet payload begins on a
         * longword boundary. Mandatory for Alpha, useful on
         * x86 too.
         */
        m_adj(m, ETHER_ALIGN);

        if (bus_dmamap_load_mbuf_sg(sc_if->sk_cdata.sk_jumbo_rx_tag,
            sc_if->sk_cdata.sk_jumbo_rx_sparemap, m, segs, &nsegs, 0) != 0) {
                m_freem(m);
                return (ENOBUFS);
        }
        KASSERT(nsegs == 1, ("%s: %d segments returned!", __func__, nsegs));

        rxd = &sc_if->sk_cdata.sk_jumbo_rxdesc[idx];
        if (rxd->rx_m != NULL) {
                bus_dmamap_sync(sc_if->sk_cdata.sk_jumbo_rx_tag, rxd->rx_dmamap,
                    BUS_DMASYNC_POSTREAD);
                bus_dmamap_unload(sc_if->sk_cdata.sk_jumbo_rx_tag,
                    rxd->rx_dmamap);
        }
        map = rxd->rx_dmamap;
        rxd->rx_dmamap = sc_if->sk_cdata.sk_jumbo_rx_sparemap;
        sc_if->sk_cdata.sk_jumbo_rx_sparemap = map;
        bus_dmamap_sync(sc_if->sk_cdata.sk_jumbo_rx_tag, rxd->rx_dmamap,
            BUS_DMASYNC_PREREAD);
        rxd->rx_m = m;
        r = &sc_if->sk_rdata.sk_jumbo_rx_ring[idx];
        r->sk_data_lo = htole32(SK_ADDR_LO(segs[0].ds_addr));
        r->sk_data_hi = htole32(SK_ADDR_HI(segs[0].ds_addr));
        r->sk_ctl = htole32(segs[0].ds_len | SK_RXSTAT | SK_OPCODE_CSUM);

        return (0);
}

/*
 * Set media options.
 */
static int
sk_ifmedia_upd(if_t ifp)
{
        struct sk_if_softc      *sc_if = if_getsoftc(ifp);
        struct mii_data         *mii;

        mii = device_get_softc(sc_if->sk_miibus);
        sk_init(sc_if);
        mii_mediachg(mii);

        return(0);
}

/*
 * Report current media status.
 */
static void
sk_ifmedia_sts(if_t ifp, struct ifmediareq *ifmr)
{
        struct sk_if_softc      *sc_if;
        struct mii_data         *mii;

        sc_if = if_getsoftc(ifp);
        mii = device_get_softc(sc_if->sk_miibus);

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

        return;
}

static int
sk_ioctl(if_t ifp, u_long command, caddr_t data)
{
        struct sk_if_softc      *sc_if = if_getsoftc(ifp);
        struct ifreq            *ifr = (struct ifreq *) data;
        int                     error, mask;
        struct mii_data         *mii;

        error = 0;
        switch(command) {
        case SIOCSIFMTU:
                if (ifr->ifr_mtu < ETHERMIN || ifr->ifr_mtu > SK_JUMBO_MTU)
                        error = EINVAL;
                else if (if_getmtu(ifp) != ifr->ifr_mtu) {
                        if (sc_if->sk_jumbo_disable != 0 &&
                            ifr->ifr_mtu > SK_MAX_FRAMELEN)
                                error = EINVAL;
                        else {
                                SK_IF_LOCK(sc_if);
                                if_setmtu(ifp, ifr->ifr_mtu);
                                if (if_getdrvflags(ifp) & IFF_DRV_RUNNING) {
                                        if_setdrvflagbits(ifp, 0, IFF_DRV_RUNNING);
                                        sk_init_locked(sc_if);
                                }
                                SK_IF_UNLOCK(sc_if);
                        }
                }
                break;
        case SIOCSIFFLAGS:
                SK_IF_LOCK(sc_if);
                if (if_getflags(ifp) & IFF_UP) {
                        if (if_getdrvflags(ifp) & IFF_DRV_RUNNING) {
                                if ((if_getflags(ifp) ^ sc_if->sk_if_flags)
                                    & (IFF_PROMISC | IFF_ALLMULTI))
                                        sk_rxfilter(sc_if);
                        } else
                                sk_init_locked(sc_if);
                } else {
                        if (if_getdrvflags(ifp) & IFF_DRV_RUNNING)
                                sk_stop(sc_if);
                }
                sc_if->sk_if_flags = if_getflags(ifp);
                SK_IF_UNLOCK(sc_if);
                break;
        case SIOCADDMULTI:
        case SIOCDELMULTI:
                SK_IF_LOCK(sc_if);
                if (if_getdrvflags(ifp) & IFF_DRV_RUNNING)
                        sk_rxfilter(sc_if);
                SK_IF_UNLOCK(sc_if);
                break;
        case SIOCGIFMEDIA:
        case SIOCSIFMEDIA:
                mii = device_get_softc(sc_if->sk_miibus);
                error = ifmedia_ioctl(ifp, ifr, &mii->mii_media, command);
                break;
        case SIOCSIFCAP:
                SK_IF_LOCK(sc_if);
                if (sc_if->sk_softc->sk_type == SK_GENESIS) {
                        SK_IF_UNLOCK(sc_if);
                        break;
                }
                mask = ifr->ifr_reqcap ^ if_getcapenable(ifp);
                if ((mask & IFCAP_TXCSUM) != 0 &&
                    (IFCAP_TXCSUM & if_getcapabilities(ifp)) != 0) {
                        if_togglecapenable(ifp, IFCAP_TXCSUM);
                        if ((if_getcapenable(ifp) & IFCAP_TXCSUM) != 0)
                                if_sethwassistbits(ifp, SK_CSUM_FEATURES, 0);
                        else
                                if_sethwassistbits(ifp, 0, SK_CSUM_FEATURES);
                }
                if ((mask & IFCAP_RXCSUM) != 0 &&
                    (IFCAP_RXCSUM & if_getcapabilities(ifp)) != 0)
                        if_togglecapenable(ifp, IFCAP_RXCSUM);
                SK_IF_UNLOCK(sc_if);
                break;
        default:
                error = ether_ioctl(ifp, command, data);
                break;
        }

        return (error);
}

/*
 * Probe for a SysKonnect GEnesis chip. Check the PCI vendor and device
 * IDs against our list and return a device name if we find a match.
 */
static int
skc_probe(device_t dev)
{
        const struct sk_type    *t = sk_devs;

        while(t->sk_name != NULL) {
                if ((pci_get_vendor(dev) == t->sk_vid) &&
                    (pci_get_device(dev) == t->sk_did)) {
                        /*
                         * Only attach to rev. 2 of the Linksys EG1032 adapter.
                         * Rev. 3 is supported by re(4).
                         */
                        if ((t->sk_vid == VENDORID_LINKSYS) &&
                                (t->sk_did == DEVICEID_LINKSYS_EG1032) &&
                                (pci_get_subdevice(dev) !=
                                 SUBDEVICEID_LINKSYS_EG1032_REV2)) {
                                t++;
                                continue;
                        }
                        device_set_desc(dev, t->sk_name);
                        return (BUS_PROBE_DEFAULT);
                }
                t++;
        }

        return(ENXIO);
}

/*
 * Force the GEnesis into reset, then bring it out of reset.
 */
static void
sk_reset(struct sk_softc *sc)
{

        CSR_WRITE_2(sc, SK_CSR, SK_CSR_SW_RESET);
        CSR_WRITE_2(sc, SK_CSR, SK_CSR_MASTER_RESET);
        if (SK_YUKON_FAMILY(sc->sk_type))
                CSR_WRITE_2(sc, SK_LINK_CTRL, SK_LINK_RESET_SET);

        DELAY(1000);
        CSR_WRITE_2(sc, SK_CSR, SK_CSR_SW_UNRESET);
        DELAY(2);
        CSR_WRITE_2(sc, SK_CSR, SK_CSR_MASTER_UNRESET);
        if (SK_YUKON_FAMILY(sc->sk_type))
                CSR_WRITE_2(sc, SK_LINK_CTRL, SK_LINK_RESET_CLEAR);

        if (sc->sk_type == SK_GENESIS) {
                /* Configure packet arbiter */
                sk_win_write_2(sc, SK_PKTARB_CTL, SK_PKTARBCTL_UNRESET);
                sk_win_write_2(sc, SK_RXPA1_TINIT, SK_PKTARB_TIMEOUT);
                sk_win_write_2(sc, SK_TXPA1_TINIT, SK_PKTARB_TIMEOUT);
                sk_win_write_2(sc, SK_RXPA2_TINIT, SK_PKTARB_TIMEOUT);
                sk_win_write_2(sc, SK_TXPA2_TINIT, SK_PKTARB_TIMEOUT);
        }

        /* Enable RAM interface */
        sk_win_write_4(sc, SK_RAMCTL, SK_RAMCTL_UNRESET);

        /*
         * Configure interrupt moderation. The moderation timer
         * defers interrupts specified in the interrupt moderation
         * timer mask based on the timeout specified in the interrupt
         * moderation timer init register. Each bit in the timer
         * register represents one tick, so to specify a timeout in
         * microseconds, we have to multiply by the correct number of
         * ticks-per-microsecond.
         */
        switch (sc->sk_type) {
        case SK_GENESIS:
                sc->sk_int_ticks = SK_IMTIMER_TICKS_GENESIS;
                break;
        default:
                sc->sk_int_ticks = SK_IMTIMER_TICKS_YUKON;
                break;
        }
        if (bootverbose)
                device_printf(sc->sk_dev, "interrupt moderation is %d us\n",
                    sc->sk_int_mod);
        sk_win_write_4(sc, SK_IMTIMERINIT, SK_IM_USECS(sc->sk_int_mod,
            sc->sk_int_ticks));
        sk_win_write_4(sc, SK_IMMR, SK_ISR_TX1_S_EOF|SK_ISR_TX2_S_EOF|
            SK_ISR_RX1_EOF|SK_ISR_RX2_EOF);
        sk_win_write_1(sc, SK_IMTIMERCTL, SK_IMCTL_START);

        return;
}

static int
sk_probe(device_t dev)
{
        struct sk_softc         *sc;

        sc = device_get_softc(device_get_parent(dev));

        /*
         * Not much to do here. We always know there will be
         * at least one XMAC present, and if there are two,
         * skc_attach() will create a second device instance
         * for us.
         */
        switch (sc->sk_type) {
        case SK_GENESIS:
                device_set_desc(dev, "XaQti Corp. XMAC II");
                break;
        case SK_YUKON:
        case SK_YUKON_LITE:
        case SK_YUKON_LP:
                device_set_desc(dev, "Marvell Semiconductor, Inc. Yukon");
                break;
        }

        return (BUS_PROBE_DEFAULT);
}

/*
 * Each XMAC chip is attached as a separate logical IP interface.
 * Single port cards will have only one logical interface of course.
 */
static int
sk_attach(device_t dev)
{
        struct sk_softc         *sc;
        struct sk_if_softc      *sc_if;
        if_t                    ifp;
        u_int32_t               r;
        int                     error, i, phy, port;
        u_char                  eaddr[6];
        u_char                  inv_mac[] = {0, 0, 0, 0, 0, 0};

        if (dev == NULL)
                return(EINVAL);

        error = 0;
        sc_if = device_get_softc(dev);
        sc = device_get_softc(device_get_parent(dev));
        port = *(int *)device_get_ivars(dev);

        sc_if->sk_if_dev = dev;
        sc_if->sk_port = port;
        sc_if->sk_softc = sc;
        sc->sk_if[port] = sc_if;
        if (port == SK_PORT_A)
                sc_if->sk_tx_bmu = SK_BMU_TXS_CSR0;
        if (port == SK_PORT_B)
                sc_if->sk_tx_bmu = SK_BMU_TXS_CSR1;

        callout_init_mtx(&sc_if->sk_tick_ch, &sc_if->sk_softc->sk_mtx, 0);
        callout_init_mtx(&sc_if->sk_watchdog_ch, &sc_if->sk_softc->sk_mtx, 0);

        if (sk_dma_alloc(sc_if) != 0) {
                error = ENOMEM;
                goto fail;
        }
        sk_dma_jumbo_alloc(sc_if);

        ifp = sc_if->sk_ifp = if_alloc(IFT_ETHER);
        if_setsoftc(ifp, sc_if);
        if_initname(ifp, device_get_name(dev), device_get_unit(dev));
        if_setflags(ifp, IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
        /*
         * SK_GENESIS has a bug in checksum offload - From linux.
         */
        if (sc_if->sk_softc->sk_type != SK_GENESIS) {
                if_setcapabilities(ifp, IFCAP_TXCSUM | IFCAP_RXCSUM);
                if_sethwassist(ifp, 0);
        } else {
                if_setcapabilities(ifp, 0);
                if_sethwassist(ifp, 0);
        }
        if_setcapenable(ifp, if_getcapabilities(ifp));
        /*
         * Some revision of Yukon controller generates corrupted
         * frame when TX checksum offloading is enabled.  The
         * frame has a valid checksum value so payload might be
         * modified during TX checksum calculation. Disable TX
         * checksum offloading but give users chance to enable it
         * when they know their controller works without problems
         * with TX checksum offloading.
         */
        if_setcapenablebit(ifp, 0, IFCAP_TXCSUM);
        if_setioctlfn(ifp, sk_ioctl);
        if_setstartfn(ifp, sk_start);
        if_setinitfn(ifp, sk_init);
        if_setsendqlen(ifp, SK_TX_RING_CNT - 1);
        if_setsendqready(ifp);

        /*
         * Get station address for this interface. Note that
         * dual port cards actually come with three station
         * addresses: one for each port, plus an extra. The
         * extra one is used by the SysKonnect driver software
         * as a 'virtual' station address for when both ports
         * are operating in failover mode. Currently we don't
         * use this extra address.
         */
        SK_IF_LOCK(sc_if);
        for (i = 0; i < ETHER_ADDR_LEN; i++)
                eaddr[i] =
                    sk_win_read_1(sc, SK_MAC0_0 + (port * 8) + i);

        /* Verify whether the station address is invalid or not. */
        if (bcmp(eaddr, inv_mac, sizeof(inv_mac)) == 0) {
                device_printf(sc_if->sk_if_dev,
                    "Generating random ethernet address\n");
                r = arc4random();
                /*
                 * Set OUI to convenient locally assigned address.  'b'
                 * is 0x62, which has the locally assigned bit set, and
                 * the broadcast/multicast bit clear.
                 */
                eaddr[0] = 'b';
                eaddr[1] = 's';
                eaddr[2] = 'd';
                eaddr[3] = (r >> 16) & 0xff;
                eaddr[4] = (r >>  8) & 0xff;
                eaddr[5] = (r >>  0) & 0xff;
        }
        /*
         * Set up RAM buffer addresses. The NIC will have a certain
         * amount of SRAM on it, somewhere between 512K and 2MB. We
         * need to divide this up a) between the transmitter and
         * receiver and b) between the two XMACs, if this is a
         * dual port NIC. Our algotithm is to divide up the memory
         * evenly so that everyone gets a fair share.
         *
         * Just to be contrary, Yukon2 appears to have separate memory
         * for each MAC.
         */
        if (sk_win_read_1(sc, SK_CONFIG) & SK_CONFIG_SINGLEMAC) {
                u_int32_t               chunk, val;

                chunk = sc->sk_ramsize / 2;
                val = sc->sk_rboff / sizeof(u_int64_t);
                sc_if->sk_rx_ramstart = val;
                val += (chunk / sizeof(u_int64_t));
                sc_if->sk_rx_ramend = val - 1;
                sc_if->sk_tx_ramstart = val;
                val += (chunk / sizeof(u_int64_t));
                sc_if->sk_tx_ramend = val - 1;
        } else {
                u_int32_t               chunk, val;

                chunk = sc->sk_ramsize / 4;
                val = (sc->sk_rboff + (chunk * 2 * sc_if->sk_port)) /
                    sizeof(u_int64_t);
                sc_if->sk_rx_ramstart = val;
                val += (chunk / sizeof(u_int64_t));
                sc_if->sk_rx_ramend = val - 1;
                sc_if->sk_tx_ramstart = val;
                val += (chunk / sizeof(u_int64_t));
                sc_if->sk_tx_ramend = val - 1;
        }

        /* Read and save PHY type and set PHY address */
        sc_if->sk_phytype = sk_win_read_1(sc, SK_EPROM1) & 0xF;
        if (!SK_YUKON_FAMILY(sc->sk_type)) {
                switch(sc_if->sk_phytype) {
                case SK_PHYTYPE_XMAC:
                        sc_if->sk_phyaddr = SK_PHYADDR_XMAC;
                        break;
                case SK_PHYTYPE_BCOM:
                        sc_if->sk_phyaddr = SK_PHYADDR_BCOM;
                        break;
                default:
                        device_printf(sc->sk_dev, "unsupported PHY type: %d\n",
                            sc_if->sk_phytype);
                        error = ENODEV;
                        SK_IF_UNLOCK(sc_if);
                        goto fail;
                }
        } else {
                if (sc_if->sk_phytype < SK_PHYTYPE_MARV_COPPER &&
                    sc->sk_pmd != 'S') {
                        /* not initialized, punt */
                        sc_if->sk_phytype = SK_PHYTYPE_MARV_COPPER;
                        sc->sk_coppertype = 1;
                }

                sc_if->sk_phyaddr = SK_PHYADDR_MARV;

                if (!(sc->sk_coppertype))
                        sc_if->sk_phytype = SK_PHYTYPE_MARV_FIBER;
        }

        /*
         * Call MI attach routine.  Can't hold locks when calling into ether_*.
         */
        SK_IF_UNLOCK(sc_if);
        ether_ifattach(ifp, eaddr);
        SK_IF_LOCK(sc_if);

        /*
         * The hardware should be ready for VLAN_MTU by default:
         * XMAC II has 0x8100 in VLAN Tag Level 1 register initially;
         * YU_SMR_MFL_VLAN is set by this driver in Yukon.
         *
         */
        if_setcapabilitiesbit(ifp, IFCAP_VLAN_MTU, 0);
        if_setcapenablebit(ifp, IFCAP_VLAN_MTU, 0);
        /*
         * Tell the upper layer(s) we support long frames.
         * Must appear after the call to ether_ifattach() because
         * ether_ifattach() sets ifi_hdrlen to the default value.
         */
        if_setifheaderlen(ifp, sizeof(struct ether_vlan_header));

        /*
         * Do miibus setup.
         */
        phy = MII_PHY_ANY;
        switch (sc->sk_type) {
        case SK_GENESIS:
                sk_init_xmac(sc_if);
                if (sc_if->sk_phytype == SK_PHYTYPE_XMAC)
                        phy = 0;
                break;
        case SK_YUKON:
        case SK_YUKON_LITE:
        case SK_YUKON_LP:
                sk_init_yukon(sc_if);
                phy = 0;
                break;
        }

        SK_IF_UNLOCK(sc_if);
        error = mii_attach(dev, &sc_if->sk_miibus, ifp, sk_ifmedia_upd,
            sk_ifmedia_sts, BMSR_DEFCAPMASK, phy, MII_OFFSET_ANY, 0);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev, "attaching PHYs failed\n");
                ether_ifdetach(ifp);
                goto fail;
        }

fail:
        if (error) {
                /* Access should be ok even though lock has been dropped */
                sc->sk_if[port] = NULL;
                sk_detach(dev);
        }

        return(error);
}

/*
 * Attach the interface. Allocate softc structures, do ifmedia
 * setup and ethernet/BPF attach.
 */
static int
skc_attach(device_t dev)
{
        struct sk_softc         *sc;
        int                     error = 0, *port;
        uint8_t                 skrs;
        const char              *pname = NULL;
        char                    *revstr;

        sc = device_get_softc(dev);
        sc->sk_dev = dev;

        mtx_init(&sc->sk_mtx, device_get_nameunit(dev), MTX_NETWORK_LOCK,
            MTX_DEF);
        mtx_init(&sc->sk_mii_mtx, "sk_mii_mutex", NULL, MTX_DEF);
        /*
         * Map control/status registers.
         */
        pci_enable_busmaster(dev);

        /* Allocate resources */
#ifdef SK_USEIOSPACE
        sc->sk_res_spec = sk_res_spec_io;
#else
        sc->sk_res_spec = sk_res_spec_mem;
#endif
        error = bus_alloc_resources(dev, sc->sk_res_spec, sc->sk_res);
        if (error) {
                if (sc->sk_res_spec == sk_res_spec_mem)
                        sc->sk_res_spec = sk_res_spec_io;
                else
                        sc->sk_res_spec = sk_res_spec_mem;
                error = bus_alloc_resources(dev, sc->sk_res_spec, sc->sk_res);
                if (error) {
                        device_printf(dev, "couldn't allocate %s resources\n",
                            sc->sk_res_spec == sk_res_spec_mem ? "memory" :
                            "I/O");
                        goto fail;
                }
        }

        sc->sk_type = sk_win_read_1(sc, SK_CHIPVER);
        sc->sk_rev = (sk_win_read_1(sc, SK_CONFIG) >> 4) & 0xf;

        /* Bail out if chip is not recognized. */
        if (sc->sk_type != SK_GENESIS && !SK_YUKON_FAMILY(sc->sk_type)) {
                device_printf(dev, "unknown device: chipver=%02x, rev=%x\n",
                    sc->sk_type, sc->sk_rev);
                error = ENXIO;
                goto fail;
        }

        SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
                SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
                OID_AUTO, "int_mod",
                CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
                &sc->sk_int_mod, 0, sysctl_hw_sk_int_mod, "I",
                "SK interrupt moderation");

        /* Pull in device tunables. */
        sc->sk_int_mod = SK_IM_DEFAULT;
        error = resource_int_value(device_get_name(dev), device_get_unit(dev),
                "int_mod", &sc->sk_int_mod);
        if (error == 0) {
                if (sc->sk_int_mod < SK_IM_MIN ||
                    sc->sk_int_mod > SK_IM_MAX) {
                        device_printf(dev, "int_mod value out of range; "
                            "using default: %d\n", SK_IM_DEFAULT);
                        sc->sk_int_mod = SK_IM_DEFAULT;
                }
        }

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

        skrs = sk_win_read_1(sc, SK_EPROM0);
        if (sc->sk_type == SK_GENESIS) {
                /* Read and save RAM size and RAMbuffer offset */
                switch(skrs) {
                case SK_RAMSIZE_512K_64:
                        sc->sk_ramsize = 0x80000;
                        sc->sk_rboff = SK_RBOFF_0;
                        break;
                case SK_RAMSIZE_1024K_64:
                        sc->sk_ramsize = 0x100000;
                        sc->sk_rboff = SK_RBOFF_80000;
                        break;
                case SK_RAMSIZE_1024K_128:
                        sc->sk_ramsize = 0x100000;
                        sc->sk_rboff = SK_RBOFF_0;
                        break;
                case SK_RAMSIZE_2048K_128:
                        sc->sk_ramsize = 0x200000;
                        sc->sk_rboff = SK_RBOFF_0;
                        break;
                default:
                        device_printf(dev, "unknown ram size: %d\n", skrs);
                        error = ENXIO;
                        goto fail;
                }
        } else { /* SK_YUKON_FAMILY */
                if (skrs == 0x00)
                        sc->sk_ramsize = 0x20000;
                else
                        sc->sk_ramsize = skrs * (1<<12);
                sc->sk_rboff = SK_RBOFF_0;
        }

        /* Read and save physical media type */
         sc->sk_pmd = sk_win_read_1(sc, SK_PMDTYPE);

         if (sc->sk_pmd == 'T' || sc->sk_pmd == '1')
                 sc->sk_coppertype = 1;
         else
                 sc->sk_coppertype = 0;

        /* Determine whether to name it with VPD PN or just make it up.
         * Marvell Yukon VPD PN seems to freqently be bogus. */
        switch (pci_get_device(dev)) {
        case DEVICEID_SK_V1:
        case DEVICEID_BELKIN_5005:
        case DEVICEID_3COM_3C940:
        case DEVICEID_LINKSYS_EG1032:
        case DEVICEID_DLINK_DGE530T_A1:
        case DEVICEID_DLINK_DGE530T_B1:
                /* Stay with VPD PN. */
                (void) pci_get_vpd_ident(dev, &pname);
                break;
        case DEVICEID_SK_V2:
                /* YUKON VPD PN might bear no resemblance to reality. */
                switch (sc->sk_type) {
                case SK_GENESIS:
                        /* Stay with VPD PN. */
                        (void) pci_get_vpd_ident(dev, &pname);
                        break;
                case SK_YUKON:
                        pname = "Marvell Yukon Gigabit Ethernet";
                        break;
                case SK_YUKON_LITE:
                        pname = "Marvell Yukon Lite Gigabit Ethernet";
                        break;
                case SK_YUKON_LP:
                        pname = "Marvell Yukon LP Gigabit Ethernet";
                        break;
                default:
                        pname = "Marvell Yukon (Unknown) Gigabit Ethernet";
                        break;
                }

                /* Yukon Lite Rev. A0 needs special test. */
                if (sc->sk_type == SK_YUKON || sc->sk_type == SK_YUKON_LP) {
                        u_int32_t far;
                        u_int8_t testbyte;

                        /* Save flash address register before testing. */
                        far = sk_win_read_4(sc, SK_EP_ADDR);

                        sk_win_write_1(sc, SK_EP_ADDR+0x03, 0xff);
                        testbyte = sk_win_read_1(sc, SK_EP_ADDR+0x03);

                        if (testbyte != 0x00) {
                                /* Yukon Lite Rev. A0 detected. */
                                sc->sk_type = SK_YUKON_LITE;
                                sc->sk_rev = SK_YUKON_LITE_REV_A0;
                                /* Restore flash address register. */
                                sk_win_write_4(sc, SK_EP_ADDR, far);
                        }
                }
                break;
        default:
                device_printf(dev, "unknown device: vendor=%04x, device=%04x, "
                        "chipver=%02x, rev=%x\n",
                        pci_get_vendor(dev), pci_get_device(dev),
                        sc->sk_type, sc->sk_rev);
                error = ENXIO;
                goto fail;
        }

        if (sc->sk_type == SK_YUKON_LITE) {
                switch (sc->sk_rev) {
                case SK_YUKON_LITE_REV_A0:
                        revstr = "A0";
                        break;
                case SK_YUKON_LITE_REV_A1:
                        revstr = "A1";
                        break;
                case SK_YUKON_LITE_REV_A3:
                        revstr = "A3";
                        break;
                default:
                        revstr = "";
                        break;
                }
        } else {
                revstr = "";
        }

        /* Announce the product name and more VPD data if there. */
        if (pname != NULL)
                device_printf(dev, "%s rev. %s(0x%x)\n",
                        pname, revstr, sc->sk_rev);

        if (bootverbose) {
                device_printf(dev, "chip ver  = 0x%02x\n", sc->sk_type);
                device_printf(dev, "chip rev  = 0x%02x\n", sc->sk_rev);
                device_printf(dev, "SK_EPROM0 = 0x%02x\n", skrs);
                device_printf(dev, "SRAM size = 0x%06x\n", sc->sk_ramsize);
        }

        sc->sk_devs[SK_PORT_A] = device_add_child(dev, "sk", DEVICE_UNIT_ANY);
        if (sc->sk_devs[SK_PORT_A] == NULL) {
                device_printf(dev, "failed to add child for PORT_A\n");
                error = ENXIO;
                goto fail;
        }
        port = malloc(sizeof(int), M_DEVBUF, M_NOWAIT);
        if (port == NULL) {
                device_printf(dev, "failed to allocate memory for "
                    "ivars of PORT_A\n");
                error = ENXIO;
                goto fail;
        }
        *port = SK_PORT_A;
        device_set_ivars(sc->sk_devs[SK_PORT_A], port);

        if (!(sk_win_read_1(sc, SK_CONFIG) & SK_CONFIG_SINGLEMAC)) {
                sc->sk_devs[SK_PORT_B] = device_add_child(dev, "sk", DEVICE_UNIT_ANY);
                if (sc->sk_devs[SK_PORT_B] == NULL) {
                        device_printf(dev, "failed to add child for PORT_B\n");
                        error = ENXIO;
                        goto fail;
                }
                port = malloc(sizeof(int), M_DEVBUF, M_NOWAIT);
                if (port == NULL) {
                        device_printf(dev, "failed to allocate memory for "
                            "ivars of PORT_B\n");
                        error = ENXIO;
                        goto fail;
                }
                *port = SK_PORT_B;
                device_set_ivars(sc->sk_devs[SK_PORT_B], port);
        }

        /* Turn on the 'driver is loaded' LED. */
        CSR_WRITE_2(sc, SK_LED, SK_LED_GREEN_ON);

        bus_attach_children(dev);

        /* Hook interrupt last to avoid having to lock softc */
        error = bus_setup_intr(dev, sc->sk_res[1], INTR_TYPE_NET|INTR_MPSAFE,
            NULL, sk_intr, sc, &sc->sk_intrhand);

        if (error) {
                device_printf(dev, "couldn't set up irq\n");
                goto fail;
        }

fail:
        if (error)
                skc_detach(dev);

        return(error);
}

static void
skc_child_deleted(device_t dev, device_t child)
{
        free(device_get_ivars(child), M_DEVBUF);
}

/*
 * 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
sk_detach(device_t dev)
{
        struct sk_if_softc      *sc_if;
        if_t                    ifp;

        sc_if = device_get_softc(dev);
        KASSERT(mtx_initialized(&sc_if->sk_softc->sk_mtx),
            ("sk mutex not initialized in sk_detach"));
        SK_IF_LOCK(sc_if);

        ifp = sc_if->sk_ifp;
        /* These should only be active if attach_xmac succeeded */
        if (device_is_attached(dev)) {
                sk_stop(sc_if);
                /* Can't hold locks while calling detach */
                SK_IF_UNLOCK(sc_if);
                callout_drain(&sc_if->sk_tick_ch);
                callout_drain(&sc_if->sk_watchdog_ch);
                ether_ifdetach(ifp);
                SK_IF_LOCK(sc_if);
        }
        bus_generic_detach(dev);
        sk_dma_jumbo_free(sc_if);
        sk_dma_free(sc_if);
        SK_IF_UNLOCK(sc_if);
        if (ifp)
                if_free(ifp);

        return(0);
}

static int
skc_detach(device_t dev)
{
        struct sk_softc         *sc;

        sc = device_get_softc(dev);
        KASSERT(mtx_initialized(&sc->sk_mtx), ("sk mutex not initialized"));

        bus_generic_detach(dev);

        if (sc->sk_intrhand)
                bus_teardown_intr(dev, sc->sk_res[1], sc->sk_intrhand);
        bus_release_resources(dev, sc->sk_res_spec, sc->sk_res);

        mtx_destroy(&sc->sk_mii_mtx);
        mtx_destroy(&sc->sk_mtx);

        return(0);
}

static bus_dma_tag_t
skc_get_dma_tag(device_t bus, device_t child __unused)
{

        return (bus_get_dma_tag(bus));
}

struct sk_dmamap_arg {
        bus_addr_t      sk_busaddr;
};

static void
sk_dmamap_cb(void *arg, bus_dma_segment_t *segs, int nseg, int error)
{
        struct sk_dmamap_arg    *ctx;

        if (error != 0)
                return;

        ctx = arg;
        ctx->sk_busaddr = segs[0].ds_addr;
}

/*
 * Allocate jumbo buffer storage. The SysKonnect adapters support
 * "jumbograms" (9K frames), although SysKonnect doesn't currently
 * use them in their drivers. In order for us to use them, we need
 * large 9K receive buffers, however standard mbuf clusters are only
 * 2048 bytes in size. Consequently, we need to allocate and manage
 * our own jumbo buffer pool. Fortunately, this does not require an
 * excessive amount of additional code.
 */
static int
sk_dma_alloc(struct sk_if_softc *sc_if)
{
        struct sk_dmamap_arg    ctx;
        struct sk_txdesc        *txd;
        struct sk_rxdesc        *rxd;
        int                     error, i;

        /* create parent tag */
        /*
         * XXX
         * This driver should use BUS_SPACE_MAXADDR for lowaddr argument
         * in bus_dma_tag_create(9) as the NIC would support DAC mode.
         * However bz@ reported that it does not work on amd64 with > 4GB
         * RAM. Until we have more clues of the breakage, disable DAC mode
         * by limiting DMA address to be in 32bit address space.
         */
        error = bus_dma_tag_create(
                    bus_get_dma_tag(sc_if->sk_if_dev),/* parent */
                    1, 0,                       /* algnmnt, boundary */
                    BUS_SPACE_MAXADDR_32BIT,    /* lowaddr */
                    BUS_SPACE_MAXADDR,          /* highaddr */
                    NULL, NULL,                 /* filter, filterarg */
                    BUS_SPACE_MAXSIZE_32BIT,    /* maxsize */
                    0,                          /* nsegments */
                    BUS_SPACE_MAXSIZE_32BIT,    /* maxsegsize */
                    0,                          /* flags */
                    NULL, NULL,                 /* lockfunc, lockarg */
                    &sc_if->sk_cdata.sk_parent_tag);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to create parent DMA tag\n");
                goto fail;
        }

        /* create tag for Tx ring */
        error = bus_dma_tag_create(sc_if->sk_cdata.sk_parent_tag,/* parent */
                    SK_RING_ALIGN, 0,           /* algnmnt, boundary */
                    BUS_SPACE_MAXADDR_32BIT,    /* lowaddr */
                    BUS_SPACE_MAXADDR,          /* highaddr */
                    NULL, NULL,                 /* filter, filterarg */
                    SK_TX_RING_SZ,              /* maxsize */
                    1,                          /* nsegments */
                    SK_TX_RING_SZ,              /* maxsegsize */
                    0,                          /* flags */
                    NULL, NULL,                 /* lockfunc, lockarg */
                    &sc_if->sk_cdata.sk_tx_ring_tag);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to allocate Tx ring DMA tag\n");
                goto fail;
        }

        /* create tag for Rx ring */
        error = bus_dma_tag_create(sc_if->sk_cdata.sk_parent_tag,/* parent */
                    SK_RING_ALIGN, 0,           /* algnmnt, boundary */
                    BUS_SPACE_MAXADDR_32BIT,    /* lowaddr */
                    BUS_SPACE_MAXADDR,          /* highaddr */
                    NULL, NULL,                 /* filter, filterarg */
                    SK_RX_RING_SZ,              /* maxsize */
                    1,                          /* nsegments */
                    SK_RX_RING_SZ,              /* maxsegsize */
                    0,                          /* flags */
                    NULL, NULL,                 /* lockfunc, lockarg */
                    &sc_if->sk_cdata.sk_rx_ring_tag);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to allocate Rx ring DMA tag\n");
                goto fail;
        }

        /* create tag for Tx buffers */
        error = bus_dma_tag_create(sc_if->sk_cdata.sk_parent_tag,/* parent */
                    1, 0,                       /* algnmnt, boundary */
                    BUS_SPACE_MAXADDR,          /* lowaddr */
                    BUS_SPACE_MAXADDR,          /* highaddr */
                    NULL, NULL,                 /* filter, filterarg */
                    MCLBYTES * SK_MAXTXSEGS,    /* maxsize */
                    SK_MAXTXSEGS,               /* nsegments */
                    MCLBYTES,                   /* maxsegsize */
                    0,                          /* flags */
                    NULL, NULL,                 /* lockfunc, lockarg */
                    &sc_if->sk_cdata.sk_tx_tag);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to allocate Tx DMA tag\n");
                goto fail;
        }

        /* create tag for Rx buffers */
        error = bus_dma_tag_create(sc_if->sk_cdata.sk_parent_tag,/* parent */
                    1, 0,                       /* algnmnt, boundary */
                    BUS_SPACE_MAXADDR,          /* lowaddr */
                    BUS_SPACE_MAXADDR,          /* highaddr */
                    NULL, NULL,                 /* filter, filterarg */
                    MCLBYTES,                   /* maxsize */
                    1,                          /* nsegments */
                    MCLBYTES,                   /* maxsegsize */
                    0,                          /* flags */
                    NULL, NULL,                 /* lockfunc, lockarg */
                    &sc_if->sk_cdata.sk_rx_tag);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to allocate Rx DMA tag\n");
                goto fail;
        }

        /* allocate DMA'able memory and load the DMA map for Tx ring */
        error = bus_dmamem_alloc(sc_if->sk_cdata.sk_tx_ring_tag,
            (void **)&sc_if->sk_rdata.sk_tx_ring, BUS_DMA_NOWAIT |
            BUS_DMA_COHERENT | BUS_DMA_ZERO, &sc_if->sk_cdata.sk_tx_ring_map);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to allocate DMA'able memory for Tx ring\n");
                goto fail;
        }

        ctx.sk_busaddr = 0;
        error = bus_dmamap_load(sc_if->sk_cdata.sk_tx_ring_tag,
            sc_if->sk_cdata.sk_tx_ring_map, sc_if->sk_rdata.sk_tx_ring,
            SK_TX_RING_SZ, sk_dmamap_cb, &ctx, BUS_DMA_NOWAIT);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to load DMA'able memory for Tx ring\n");
                goto fail;
        }
        sc_if->sk_rdata.sk_tx_ring_paddr = ctx.sk_busaddr;

        /* allocate DMA'able memory and load the DMA map for Rx ring */
        error = bus_dmamem_alloc(sc_if->sk_cdata.sk_rx_ring_tag,
            (void **)&sc_if->sk_rdata.sk_rx_ring, BUS_DMA_NOWAIT |
            BUS_DMA_COHERENT | BUS_DMA_ZERO, &sc_if->sk_cdata.sk_rx_ring_map);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to allocate DMA'able memory for Rx ring\n");
                goto fail;
        }

        ctx.sk_busaddr = 0;
        error = bus_dmamap_load(sc_if->sk_cdata.sk_rx_ring_tag,
            sc_if->sk_cdata.sk_rx_ring_map, sc_if->sk_rdata.sk_rx_ring,
            SK_RX_RING_SZ, sk_dmamap_cb, &ctx, BUS_DMA_NOWAIT);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to load DMA'able memory for Rx ring\n");
                goto fail;
        }
        sc_if->sk_rdata.sk_rx_ring_paddr = ctx.sk_busaddr;

        /* create DMA maps for Tx buffers */
        for (i = 0; i < SK_TX_RING_CNT; i++) {
                txd = &sc_if->sk_cdata.sk_txdesc[i];
                txd->tx_m = NULL;
                txd->tx_dmamap = NULL;
                error = bus_dmamap_create(sc_if->sk_cdata.sk_tx_tag, 0,
                    &txd->tx_dmamap);
                if (error != 0) {
                        device_printf(sc_if->sk_if_dev,
                            "failed to create Tx dmamap\n");
                        goto fail;
                }
        }

        /* create DMA maps for Rx buffers */
        if ((error = bus_dmamap_create(sc_if->sk_cdata.sk_rx_tag, 0,
            &sc_if->sk_cdata.sk_rx_sparemap)) != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to create spare Rx dmamap\n");
                goto fail;
        }
        for (i = 0; i < SK_RX_RING_CNT; i++) {
                rxd = &sc_if->sk_cdata.sk_rxdesc[i];
                rxd->rx_m = NULL;
                rxd->rx_dmamap = NULL;
                error = bus_dmamap_create(sc_if->sk_cdata.sk_rx_tag, 0,
                    &rxd->rx_dmamap);
                if (error != 0) {
                        device_printf(sc_if->sk_if_dev,
                            "failed to create Rx dmamap\n");
                        goto fail;
                }
        }

fail:
        return (error);
}

static int
sk_dma_jumbo_alloc(struct sk_if_softc *sc_if)
{
        struct sk_dmamap_arg    ctx;
        struct sk_rxdesc        *jrxd;
        int                     error, i;

        if (jumbo_disable != 0) {
                device_printf(sc_if->sk_if_dev, "disabling jumbo frame support\n");
                sc_if->sk_jumbo_disable = 1;
                return (0);
        }
        /* create tag for jumbo Rx ring */
        error = bus_dma_tag_create(sc_if->sk_cdata.sk_parent_tag,/* parent */
                    SK_RING_ALIGN, 0,           /* algnmnt, boundary */
                    BUS_SPACE_MAXADDR_32BIT,    /* lowaddr */
                    BUS_SPACE_MAXADDR,          /* highaddr */
                    NULL, NULL,                 /* filter, filterarg */
                    SK_JUMBO_RX_RING_SZ,        /* maxsize */
                    1,                          /* nsegments */
                    SK_JUMBO_RX_RING_SZ,        /* maxsegsize */
                    0,                          /* flags */
                    NULL, NULL,                 /* lockfunc, lockarg */
                    &sc_if->sk_cdata.sk_jumbo_rx_ring_tag);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to allocate jumbo Rx ring DMA tag\n");
                goto jumbo_fail;
        }

        /* create tag for jumbo Rx buffers */
        error = bus_dma_tag_create(sc_if->sk_cdata.sk_parent_tag,/* parent */
                    1, 0,                       /* algnmnt, boundary */
                    BUS_SPACE_MAXADDR,          /* lowaddr */
                    BUS_SPACE_MAXADDR,          /* highaddr */
                    NULL, NULL,                 /* filter, filterarg */
                    MJUM9BYTES,                 /* maxsize */
                    1,                          /* nsegments */
                    MJUM9BYTES,                 /* maxsegsize */
                    0,                          /* flags */
                    NULL, NULL,                 /* lockfunc, lockarg */
                    &sc_if->sk_cdata.sk_jumbo_rx_tag);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to allocate jumbo Rx DMA tag\n");
                goto jumbo_fail;
        }

        /* allocate DMA'able memory and load the DMA map for jumbo Rx ring */
        error = bus_dmamem_alloc(sc_if->sk_cdata.sk_jumbo_rx_ring_tag,
            (void **)&sc_if->sk_rdata.sk_jumbo_rx_ring, BUS_DMA_NOWAIT |
            BUS_DMA_COHERENT | BUS_DMA_ZERO,
            &sc_if->sk_cdata.sk_jumbo_rx_ring_map);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to allocate DMA'able memory for jumbo Rx ring\n");
                goto jumbo_fail;
        }

        ctx.sk_busaddr = 0;
        error = bus_dmamap_load(sc_if->sk_cdata.sk_jumbo_rx_ring_tag,
            sc_if->sk_cdata.sk_jumbo_rx_ring_map,
            sc_if->sk_rdata.sk_jumbo_rx_ring, SK_JUMBO_RX_RING_SZ, sk_dmamap_cb,
            &ctx, BUS_DMA_NOWAIT);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to load DMA'able memory for jumbo Rx ring\n");
                goto jumbo_fail;
        }
        sc_if->sk_rdata.sk_jumbo_rx_ring_paddr = ctx.sk_busaddr;

        /* create DMA maps for jumbo Rx buffers */
        if ((error = bus_dmamap_create(sc_if->sk_cdata.sk_jumbo_rx_tag, 0,
            &sc_if->sk_cdata.sk_jumbo_rx_sparemap)) != 0) {
                device_printf(sc_if->sk_if_dev,
                    "failed to create spare jumbo Rx dmamap\n");
                goto jumbo_fail;
        }
        for (i = 0; i < SK_JUMBO_RX_RING_CNT; i++) {
                jrxd = &sc_if->sk_cdata.sk_jumbo_rxdesc[i];
                jrxd->rx_m = NULL;
                jrxd->rx_dmamap = NULL;
                error = bus_dmamap_create(sc_if->sk_cdata.sk_jumbo_rx_tag, 0,
                    &jrxd->rx_dmamap);
                if (error != 0) {
                        device_printf(sc_if->sk_if_dev,
                            "failed to create jumbo Rx dmamap\n");
                        goto jumbo_fail;
                }
        }

        return (0);

jumbo_fail:
        sk_dma_jumbo_free(sc_if);
        device_printf(sc_if->sk_if_dev, "disabling jumbo frame support due to "
            "resource shortage\n");
        sc_if->sk_jumbo_disable = 1;
        return (0);
}

static void
sk_dma_free(struct sk_if_softc *sc_if)
{
        struct sk_txdesc        *txd;
        struct sk_rxdesc        *rxd;
        int                     i;

        /* Tx ring */
        if (sc_if->sk_cdata.sk_tx_ring_tag) {
                if (sc_if->sk_rdata.sk_tx_ring_paddr)
                        bus_dmamap_unload(sc_if->sk_cdata.sk_tx_ring_tag,
                            sc_if->sk_cdata.sk_tx_ring_map);
                if (sc_if->sk_rdata.sk_tx_ring)
                        bus_dmamem_free(sc_if->sk_cdata.sk_tx_ring_tag,
                            sc_if->sk_rdata.sk_tx_ring,
                            sc_if->sk_cdata.sk_tx_ring_map);
                sc_if->sk_rdata.sk_tx_ring = NULL;
                sc_if->sk_rdata.sk_tx_ring_paddr = 0;
                bus_dma_tag_destroy(sc_if->sk_cdata.sk_tx_ring_tag);
                sc_if->sk_cdata.sk_tx_ring_tag = NULL;
        }
        /* Rx ring */
        if (sc_if->sk_cdata.sk_rx_ring_tag) {
                if (sc_if->sk_rdata.sk_rx_ring_paddr)
                        bus_dmamap_unload(sc_if->sk_cdata.sk_rx_ring_tag,
                            sc_if->sk_cdata.sk_rx_ring_map);
                if (sc_if->sk_rdata.sk_rx_ring)
                        bus_dmamem_free(sc_if->sk_cdata.sk_rx_ring_tag,
                            sc_if->sk_rdata.sk_rx_ring,
                            sc_if->sk_cdata.sk_rx_ring_map);
                sc_if->sk_rdata.sk_rx_ring = NULL;
                sc_if->sk_rdata.sk_rx_ring_paddr = 0;
                bus_dma_tag_destroy(sc_if->sk_cdata.sk_rx_ring_tag);
                sc_if->sk_cdata.sk_rx_ring_tag = NULL;
        }
        /* Tx buffers */
        if (sc_if->sk_cdata.sk_tx_tag) {
                for (i = 0; i < SK_TX_RING_CNT; i++) {
                        txd = &sc_if->sk_cdata.sk_txdesc[i];
                        if (txd->tx_dmamap) {
                                bus_dmamap_destroy(sc_if->sk_cdata.sk_tx_tag,
                                    txd->tx_dmamap);
                                txd->tx_dmamap = NULL;
                        }
                }
                bus_dma_tag_destroy(sc_if->sk_cdata.sk_tx_tag);
                sc_if->sk_cdata.sk_tx_tag = NULL;
        }
        /* Rx buffers */
        if (sc_if->sk_cdata.sk_rx_tag) {
                for (i = 0; i < SK_RX_RING_CNT; i++) {
                        rxd = &sc_if->sk_cdata.sk_rxdesc[i];
                        if (rxd->rx_dmamap) {
                                bus_dmamap_destroy(sc_if->sk_cdata.sk_rx_tag,
                                    rxd->rx_dmamap);
                                rxd->rx_dmamap = NULL;
                        }
                }
                if (sc_if->sk_cdata.sk_rx_sparemap) {
                        bus_dmamap_destroy(sc_if->sk_cdata.sk_rx_tag,
                            sc_if->sk_cdata.sk_rx_sparemap);
                        sc_if->sk_cdata.sk_rx_sparemap = NULL;
                }
                bus_dma_tag_destroy(sc_if->sk_cdata.sk_rx_tag);
                sc_if->sk_cdata.sk_rx_tag = NULL;
        }

        if (sc_if->sk_cdata.sk_parent_tag) {
                bus_dma_tag_destroy(sc_if->sk_cdata.sk_parent_tag);
                sc_if->sk_cdata.sk_parent_tag = NULL;
        }
}

static void
sk_dma_jumbo_free(struct sk_if_softc *sc_if)
{
        struct sk_rxdesc        *jrxd;
        int                     i;

        /* jumbo Rx ring */
        if (sc_if->sk_cdata.sk_jumbo_rx_ring_tag) {
                if (sc_if->sk_rdata.sk_jumbo_rx_ring_paddr)
                        bus_dmamap_unload(sc_if->sk_cdata.sk_jumbo_rx_ring_tag,
                            sc_if->sk_cdata.sk_jumbo_rx_ring_map);
                if (sc_if->sk_rdata.sk_jumbo_rx_ring)
                        bus_dmamem_free(sc_if->sk_cdata.sk_jumbo_rx_ring_tag,
                            sc_if->sk_rdata.sk_jumbo_rx_ring,
                            sc_if->sk_cdata.sk_jumbo_rx_ring_map);
                sc_if->sk_rdata.sk_jumbo_rx_ring = NULL;
                sc_if->sk_rdata.sk_jumbo_rx_ring_paddr = 0;
                bus_dma_tag_destroy(sc_if->sk_cdata.sk_jumbo_rx_ring_tag);
                sc_if->sk_cdata.sk_jumbo_rx_ring_tag = NULL;
        }

        /* jumbo Rx buffers */
        if (sc_if->sk_cdata.sk_jumbo_rx_tag) {
                for (i = 0; i < SK_JUMBO_RX_RING_CNT; i++) {
                        jrxd = &sc_if->sk_cdata.sk_jumbo_rxdesc[i];
                        if (jrxd->rx_dmamap) {
                                bus_dmamap_destroy(
                                    sc_if->sk_cdata.sk_jumbo_rx_tag,
                                    jrxd->rx_dmamap);
                                jrxd->rx_dmamap = NULL;
                        }
                }
                if (sc_if->sk_cdata.sk_jumbo_rx_sparemap) {
                        bus_dmamap_destroy(sc_if->sk_cdata.sk_jumbo_rx_tag,
                            sc_if->sk_cdata.sk_jumbo_rx_sparemap);
                        sc_if->sk_cdata.sk_jumbo_rx_sparemap = NULL;
                }
                bus_dma_tag_destroy(sc_if->sk_cdata.sk_jumbo_rx_tag);
                sc_if->sk_cdata.sk_jumbo_rx_tag = NULL;
        }
}

static void
sk_txcksum(if_t ifp, struct mbuf *m, struct sk_tx_desc *f)
{
        struct ip               *ip;
        u_int16_t               offset;
        u_int8_t                *p;

        offset = sizeof(struct ip) + ETHER_HDR_LEN;
        for(; m && m->m_len == 0; m = m->m_next)
                ;
        if (m == NULL || m->m_len < ETHER_HDR_LEN) {
                if_printf(ifp, "%s: m_len < ETHER_HDR_LEN\n", __func__);
                /* checksum may be corrupted */
                goto sendit;
        }
        if (m->m_len < ETHER_HDR_LEN + sizeof(u_int32_t)) {
                if (m->m_len != ETHER_HDR_LEN) {
                        if_printf(ifp, "%s: m_len != ETHER_HDR_LEN\n",
                            __func__);
                        /* checksum may be corrupted */
                        goto sendit;
                }
                for(m = m->m_next; m && m->m_len == 0; m = m->m_next)
                        ;
                if (m == NULL) {
                        offset = sizeof(struct ip) + ETHER_HDR_LEN;
                        /* checksum may be corrupted */
                        goto sendit;
                }
                ip = mtod(m, struct ip *);
        } else {
                p = mtod(m, u_int8_t *);
                p += ETHER_HDR_LEN;
                ip = (struct ip *)p;
        }
        offset = (ip->ip_hl << 2) + ETHER_HDR_LEN;

sendit:
        f->sk_csum_startval = 0;
        f->sk_csum_start = htole32(((offset + m->m_pkthdr.csum_data) & 0xffff) |
            (offset << 16));
}

static int
sk_encap(struct sk_if_softc *sc_if, struct mbuf **m_head)
{
        struct sk_txdesc        *txd;
        struct sk_tx_desc       *f = NULL;
        struct mbuf             *m;
        bus_dma_segment_t       txsegs[SK_MAXTXSEGS];
        u_int32_t               cflags, frag, si, sk_ctl;
        int                     error, i, nseg;

        SK_IF_LOCK_ASSERT(sc_if);

        if ((txd = STAILQ_FIRST(&sc_if->sk_cdata.sk_txfreeq)) == NULL)
                return (ENOBUFS);

        error = bus_dmamap_load_mbuf_sg(sc_if->sk_cdata.sk_tx_tag,
            txd->tx_dmamap, *m_head, txsegs, &nseg, 0);
        if (error == EFBIG) {
                m = m_defrag(*m_head, M_NOWAIT);
                if (m == NULL) {
                        m_freem(*m_head);
                        *m_head = NULL;
                        return (ENOMEM);
                }
                *m_head = m;
                error = bus_dmamap_load_mbuf_sg(sc_if->sk_cdata.sk_tx_tag,
                    txd->tx_dmamap, *m_head, txsegs, &nseg, 0);
                if (error != 0) {
                        m_freem(*m_head);
                        *m_head = NULL;
                        return (error);
                }
        } else if (error != 0)
                return (error);
        if (nseg == 0) {
                m_freem(*m_head);
                *m_head = NULL;
                return (EIO);
        }
        if (sc_if->sk_cdata.sk_tx_cnt + nseg >= SK_TX_RING_CNT) {
                bus_dmamap_unload(sc_if->sk_cdata.sk_tx_tag, txd->tx_dmamap);
                return (ENOBUFS);
        }

        m = *m_head;
        if ((m->m_pkthdr.csum_flags & if_gethwassist(sc_if->sk_ifp)) != 0)
                cflags = SK_OPCODE_CSUM;
        else
                cflags = SK_OPCODE_DEFAULT;
        si = frag = sc_if->sk_cdata.sk_tx_prod;
        for (i = 0; i < nseg; i++) {
                f = &sc_if->sk_rdata.sk_tx_ring[frag];
                f->sk_data_lo = htole32(SK_ADDR_LO(txsegs[i].ds_addr));
                f->sk_data_hi = htole32(SK_ADDR_HI(txsegs[i].ds_addr));
                sk_ctl = txsegs[i].ds_len | cflags;
                if (i == 0) {
                        if (cflags == SK_OPCODE_CSUM)
                                sk_txcksum(sc_if->sk_ifp, m, f);
                        sk_ctl |= SK_TXCTL_FIRSTFRAG;
                } else
                        sk_ctl |= SK_TXCTL_OWN;
                f->sk_ctl = htole32(sk_ctl);
                sc_if->sk_cdata.sk_tx_cnt++;
                SK_INC(frag, SK_TX_RING_CNT);
        }
        sc_if->sk_cdata.sk_tx_prod = frag;

        /* set EOF on the last descriptor */
        frag = (frag + SK_TX_RING_CNT - 1) % SK_TX_RING_CNT;
        f = &sc_if->sk_rdata.sk_tx_ring[frag];
        f->sk_ctl |= htole32(SK_TXCTL_LASTFRAG | SK_TXCTL_EOF_INTR);

        /* turn the first descriptor ownership to NIC */
        f = &sc_if->sk_rdata.sk_tx_ring[si];
        f->sk_ctl |= htole32(SK_TXCTL_OWN);

        STAILQ_REMOVE_HEAD(&sc_if->sk_cdata.sk_txfreeq, tx_q);
        STAILQ_INSERT_TAIL(&sc_if->sk_cdata.sk_txbusyq, txd, tx_q);
        txd->tx_m = m;

        /* sync descriptors */
        bus_dmamap_sync(sc_if->sk_cdata.sk_tx_tag, txd->tx_dmamap,
            BUS_DMASYNC_PREWRITE);
        bus_dmamap_sync(sc_if->sk_cdata.sk_tx_ring_tag,
            sc_if->sk_cdata.sk_tx_ring_map,
            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);

        return (0);
}

static void
sk_start(if_t ifp)
{
        struct sk_if_softc *sc_if;

        sc_if = if_getsoftc(ifp);

        SK_IF_LOCK(sc_if);
        sk_start_locked(ifp);
        SK_IF_UNLOCK(sc_if);

        return;
}

static void
sk_start_locked(if_t ifp)
{
        struct sk_softc         *sc;
        struct sk_if_softc      *sc_if;
        struct mbuf             *m_head;
        int                     enq;

        sc_if = if_getsoftc(ifp);
        sc = sc_if->sk_softc;

        SK_IF_LOCK_ASSERT(sc_if);

        for (enq = 0; !if_sendq_empty(ifp) &&
            sc_if->sk_cdata.sk_tx_cnt < SK_TX_RING_CNT - 1; ) {
                m_head = if_dequeue(ifp);
                if (m_head == NULL)
                        break;

                /*
                 * Pack the data into the transmit ring. If we
                 * don't have room, set the OACTIVE flag and wait
                 * for the NIC to drain the ring.
                 */
                if (sk_encap(sc_if, &m_head)) {
                        if (m_head == NULL)
                                break;
                        if_sendq_prepend(ifp, m_head);
                        if_setdrvflagbits(ifp, IFF_DRV_OACTIVE, 0);
                        break;
                }

                enq++;
                /*
                 * If there's a BPF listener, bounce a copy of this frame
                 * to him.
                 */
                BPF_MTAP(ifp, m_head);
        }

        if (enq > 0) {
                /* Transmit */
                CSR_WRITE_4(sc, sc_if->sk_tx_bmu, SK_TXBMU_TX_START);

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

static void
sk_watchdog(void *arg)
{
        struct sk_if_softc      *sc_if;
        if_t                    ifp;

        ifp = arg;
        sc_if = if_getsoftc(ifp);

        SK_IF_LOCK_ASSERT(sc_if);

        if (sc_if->sk_watchdog_timer == 0 || --sc_if->sk_watchdog_timer)
                goto done;

        /*
         * Reclaim first as there is a possibility of losing Tx completion
         * interrupts.
         */
        sk_txeof(sc_if);
        if (sc_if->sk_cdata.sk_tx_cnt != 0) {
                if_printf(sc_if->sk_ifp, "watchdog timeout\n");
                if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
                if_setdrvflagbits(ifp, 0, IFF_DRV_RUNNING);
                sk_init_locked(sc_if);
        }

done:
        callout_reset(&sc_if->sk_watchdog_ch, hz, sk_watchdog, ifp);

        return;
}

static int
skc_shutdown(device_t dev)
{
        struct sk_softc         *sc;

        sc = device_get_softc(dev);
        SK_LOCK(sc);

        /* Turn off the 'driver is loaded' LED. */
        CSR_WRITE_2(sc, SK_LED, SK_LED_GREEN_OFF);

        /*
         * Reset the GEnesis controller. Doing this should also
         * assert the resets on the attached XMAC(s).
         */
        sk_reset(sc);
        SK_UNLOCK(sc);

        return (0);
}

static int
skc_suspend(device_t dev)
{
        struct sk_softc         *sc;
        struct sk_if_softc      *sc_if0, *sc_if1;
        if_t                    ifp0 = NULL, ifp1 = NULL;

        sc = device_get_softc(dev);

        SK_LOCK(sc);

        sc_if0 = sc->sk_if[SK_PORT_A];
        sc_if1 = sc->sk_if[SK_PORT_B];
        if (sc_if0 != NULL)
                ifp0 = sc_if0->sk_ifp;
        if (sc_if1 != NULL)
                ifp1 = sc_if1->sk_ifp;
        if (ifp0 != NULL)
                sk_stop(sc_if0);
        if (ifp1 != NULL)
                sk_stop(sc_if1);
        sc->sk_suspended = 1;

        SK_UNLOCK(sc);

        return (0);
}

static int
skc_resume(device_t dev)
{
        struct sk_softc         *sc;
        struct sk_if_softc      *sc_if0, *sc_if1;
        if_t                    ifp0 = NULL, ifp1 = NULL;

        sc = device_get_softc(dev);

        SK_LOCK(sc);

        sc_if0 = sc->sk_if[SK_PORT_A];
        sc_if1 = sc->sk_if[SK_PORT_B];
        if (sc_if0 != NULL)
                ifp0 = sc_if0->sk_ifp;
        if (sc_if1 != NULL)
                ifp1 = sc_if1->sk_ifp;
        if (ifp0 != NULL && if_getflags(ifp0) & IFF_UP)
                sk_init_locked(sc_if0);
        if (ifp1 != NULL && if_getflags(ifp1) & IFF_UP)
                sk_init_locked(sc_if1);
        sc->sk_suspended = 0;

        SK_UNLOCK(sc);

        return (0);
}

/*
 * According to the data sheet from SK-NET GENESIS the hardware can compute
 * two Rx checksums at the same time(Each checksum start position is
 * programmed in Rx descriptors). However it seems that TCP/UDP checksum
 * does not work at least on my Yukon hardware. I tried every possible ways
 * to get correct checksum value but couldn't get correct one. So TCP/UDP
 * checksum offload was disabled at the moment and only IP checksum offload
 * was enabled.
 * As normal IP header size is 20 bytes I can't expect it would give an
 * increase in throughput. However it seems it doesn't hurt performance in
 * my testing. If there is a more detailed information for checksum secret
 * of the hardware in question please contact yongari@FreeBSD.org to add
 * TCP/UDP checksum offload support.
 */
static __inline void
sk_rxcksum(if_t ifp, struct mbuf *m, u_int32_t csum)
{
        struct ether_header     *eh;
        struct ip               *ip;
        int32_t                 hlen, len, pktlen;
        u_int16_t               csum1, csum2, ipcsum;

        pktlen = m->m_pkthdr.len;
        if (pktlen < sizeof(struct ether_header) + sizeof(struct ip))
                return;
        eh = mtod(m, struct ether_header *);
        if (eh->ether_type != htons(ETHERTYPE_IP))
                return;
        ip = (struct ip *)(eh + 1);
        if (ip->ip_v != IPVERSION)
                return;
        hlen = ip->ip_hl << 2;
        pktlen -= sizeof(struct ether_header);
        if (hlen < sizeof(struct ip))
                return;
        if (ntohs(ip->ip_len) < hlen)
                return;
        if (ntohs(ip->ip_len) != pktlen)
                return;

        csum1 = htons(csum & 0xffff);
        csum2 = htons((csum >> 16) & 0xffff);
        ipcsum = in_addword(csum1, ~csum2 & 0xffff);
        /* checksum fixup for IP options */
        len = hlen - sizeof(struct ip);
        if (len > 0) {
                /*
                 * If the second checksum value is correct we can compute IP
                 * checksum with simple math. Unfortunately the second checksum
                 * value is wrong so we can't verify the checksum from the
                 * value(It seems there is some magic here to get correct
                 * value). If the second checksum value is correct it also
                 * means we can get TCP/UDP checksum) here. However, it still
                 * needs pseudo header checksum calculation due to hardware
                 * limitations.
                 */
                return;
        }
        m->m_pkthdr.csum_flags = CSUM_IP_CHECKED;
        if (ipcsum == 0xffff)
                m->m_pkthdr.csum_flags |= CSUM_IP_VALID;
}

static __inline int
sk_rxvalid(struct sk_softc *sc, u_int32_t stat, u_int32_t len)
{

        if (sc->sk_type == SK_GENESIS) {
                if ((stat & XM_RXSTAT_ERRFRAME) == XM_RXSTAT_ERRFRAME ||
                    XM_RXSTAT_BYTES(stat) != len)
                        return (0);
        } else {
                if ((stat & (YU_RXSTAT_CRCERR | YU_RXSTAT_LONGERR |
                    YU_RXSTAT_MIIERR | YU_RXSTAT_BADFC | YU_RXSTAT_GOODFC |
                    YU_RXSTAT_JABBER)) != 0 ||
                    (stat & YU_RXSTAT_RXOK) != YU_RXSTAT_RXOK ||
                    YU_RXSTAT_BYTES(stat) != len)
                        return (0);
        }

        return (1);
}

static void
sk_rxeof(struct sk_if_softc *sc_if)
{
        struct sk_softc         *sc;
        struct mbuf             *m;
        if_t                    ifp;
        struct sk_rx_desc       *cur_rx;
        struct sk_rxdesc        *rxd;
        int                     cons, prog;
        u_int32_t               csum, rxstat, sk_ctl;

        sc = sc_if->sk_softc;
        ifp = sc_if->sk_ifp;

        SK_IF_LOCK_ASSERT(sc_if);

        bus_dmamap_sync(sc_if->sk_cdata.sk_rx_ring_tag,
            sc_if->sk_cdata.sk_rx_ring_map, BUS_DMASYNC_POSTREAD);

        prog = 0;
        for (cons = sc_if->sk_cdata.sk_rx_cons; prog < SK_RX_RING_CNT;
            prog++, SK_INC(cons, SK_RX_RING_CNT)) {
                cur_rx = &sc_if->sk_rdata.sk_rx_ring[cons];
                sk_ctl = le32toh(cur_rx->sk_ctl);
                if ((sk_ctl & SK_RXCTL_OWN) != 0)
                        break;
                rxd = &sc_if->sk_cdata.sk_rxdesc[cons];
                rxstat = le32toh(cur_rx->sk_xmac_rxstat);

                if ((sk_ctl & (SK_RXCTL_STATUS_VALID | SK_RXCTL_FIRSTFRAG |
                    SK_RXCTL_LASTFRAG)) != (SK_RXCTL_STATUS_VALID |
                    SK_RXCTL_FIRSTFRAG | SK_RXCTL_LASTFRAG) ||
                    SK_RXBYTES(sk_ctl) < SK_MIN_FRAMELEN ||
                    SK_RXBYTES(sk_ctl) > SK_MAX_FRAMELEN ||
                    sk_rxvalid(sc, rxstat, SK_RXBYTES(sk_ctl)) == 0) {
                        if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
                        sk_discard_rxbuf(sc_if, cons);
                        continue;
                }

                m = rxd->rx_m;
                csum = le32toh(cur_rx->sk_csum);
                if (sk_newbuf(sc_if, cons) != 0) {
                        if_inc_counter(ifp, IFCOUNTER_IQDROPS, 1);
                        /* reuse old buffer */
                        sk_discard_rxbuf(sc_if, cons);
                        continue;
                }
                m->m_pkthdr.rcvif = ifp;
                m->m_pkthdr.len = m->m_len = SK_RXBYTES(sk_ctl);
                if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
                if ((if_getcapenable(ifp) & IFCAP_RXCSUM) != 0)
                        sk_rxcksum(ifp, m, csum);
                SK_IF_UNLOCK(sc_if);
                if_input(ifp, m);
                SK_IF_LOCK(sc_if);
        }

        if (prog > 0) {
                sc_if->sk_cdata.sk_rx_cons = cons;
                bus_dmamap_sync(sc_if->sk_cdata.sk_rx_ring_tag,
                    sc_if->sk_cdata.sk_rx_ring_map,
                    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
        }
}

static void
sk_jumbo_rxeof(struct sk_if_softc *sc_if)
{
        struct sk_softc         *sc;
        struct mbuf             *m;
        if_t                    ifp;
        struct sk_rx_desc       *cur_rx;
        struct sk_rxdesc        *jrxd;
        int                     cons, prog;
        u_int32_t               csum, rxstat, sk_ctl;

        sc = sc_if->sk_softc;
        ifp = sc_if->sk_ifp;

        SK_IF_LOCK_ASSERT(sc_if);

        bus_dmamap_sync(sc_if->sk_cdata.sk_jumbo_rx_ring_tag,
            sc_if->sk_cdata.sk_jumbo_rx_ring_map, BUS_DMASYNC_POSTREAD);

        prog = 0;
        for (cons = sc_if->sk_cdata.sk_jumbo_rx_cons;
            prog < SK_JUMBO_RX_RING_CNT;
            prog++, SK_INC(cons, SK_JUMBO_RX_RING_CNT)) {
                cur_rx = &sc_if->sk_rdata.sk_jumbo_rx_ring[cons];
                sk_ctl = le32toh(cur_rx->sk_ctl);
                if ((sk_ctl & SK_RXCTL_OWN) != 0)
                        break;
                jrxd = &sc_if->sk_cdata.sk_jumbo_rxdesc[cons];
                rxstat = le32toh(cur_rx->sk_xmac_rxstat);

                if ((sk_ctl & (SK_RXCTL_STATUS_VALID | SK_RXCTL_FIRSTFRAG |
                    SK_RXCTL_LASTFRAG)) != (SK_RXCTL_STATUS_VALID |
                    SK_RXCTL_FIRSTFRAG | SK_RXCTL_LASTFRAG) ||
                    SK_RXBYTES(sk_ctl) < SK_MIN_FRAMELEN ||
                    SK_RXBYTES(sk_ctl) > SK_JUMBO_FRAMELEN ||
                    sk_rxvalid(sc, rxstat, SK_RXBYTES(sk_ctl)) == 0) {
                        if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
                        sk_discard_jumbo_rxbuf(sc_if, cons);
                        continue;
                }

                m = jrxd->rx_m;
                csum = le32toh(cur_rx->sk_csum);
                if (sk_jumbo_newbuf(sc_if, cons) != 0) {
                        if_inc_counter(ifp, IFCOUNTER_IQDROPS, 1);
                        /* reuse old buffer */
                        sk_discard_jumbo_rxbuf(sc_if, cons);
                        continue;
                }
                m->m_pkthdr.rcvif = ifp;
                m->m_pkthdr.len = m->m_len = SK_RXBYTES(sk_ctl);
                if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
                if ((if_getcapenable(ifp) & IFCAP_RXCSUM) != 0)
                        sk_rxcksum(ifp, m, csum);
                SK_IF_UNLOCK(sc_if);
                if_input(ifp, m);
                SK_IF_LOCK(sc_if);
        }

        if (prog > 0) {
                sc_if->sk_cdata.sk_jumbo_rx_cons = cons;
                bus_dmamap_sync(sc_if->sk_cdata.sk_jumbo_rx_ring_tag,
                    sc_if->sk_cdata.sk_jumbo_rx_ring_map,
                    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
        }
}

static void
sk_txeof(struct sk_if_softc *sc_if)
{
        struct sk_txdesc        *txd;
        struct sk_tx_desc       *cur_tx;
        if_t                    ifp;
        u_int32_t               idx, sk_ctl;

        ifp = sc_if->sk_ifp;

        txd = STAILQ_FIRST(&sc_if->sk_cdata.sk_txbusyq);
        if (txd == NULL)
                return;
        bus_dmamap_sync(sc_if->sk_cdata.sk_tx_ring_tag,
            sc_if->sk_cdata.sk_tx_ring_map, BUS_DMASYNC_POSTREAD);
        /*
         * Go through our tx ring and free mbufs for those
         * frames that have been sent.
         */
        for (idx = sc_if->sk_cdata.sk_tx_cons;; SK_INC(idx, SK_TX_RING_CNT)) {
                if (sc_if->sk_cdata.sk_tx_cnt <= 0)
                        break;
                cur_tx = &sc_if->sk_rdata.sk_tx_ring[idx];
                sk_ctl = le32toh(cur_tx->sk_ctl);
                if (sk_ctl & SK_TXCTL_OWN)
                        break;
                sc_if->sk_cdata.sk_tx_cnt--;
                if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);
                if ((sk_ctl & SK_TXCTL_LASTFRAG) == 0)
                        continue;
                bus_dmamap_sync(sc_if->sk_cdata.sk_tx_tag, txd->tx_dmamap,
                    BUS_DMASYNC_POSTWRITE);
                bus_dmamap_unload(sc_if->sk_cdata.sk_tx_tag, txd->tx_dmamap);

                if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
                m_freem(txd->tx_m);
                txd->tx_m = NULL;
                STAILQ_REMOVE_HEAD(&sc_if->sk_cdata.sk_txbusyq, tx_q);
                STAILQ_INSERT_TAIL(&sc_if->sk_cdata.sk_txfreeq, txd, tx_q);
                txd = STAILQ_FIRST(&sc_if->sk_cdata.sk_txbusyq);
        }
        sc_if->sk_cdata.sk_tx_cons = idx;
        sc_if->sk_watchdog_timer = sc_if->sk_cdata.sk_tx_cnt > 0 ? 5 : 0;

        bus_dmamap_sync(sc_if->sk_cdata.sk_tx_ring_tag,
            sc_if->sk_cdata.sk_tx_ring_map,
            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
}

static void
sk_tick(void *xsc_if)
{
        struct sk_if_softc      *sc_if;
        struct mii_data         *mii;
        if_t                    ifp;
        int                     i;

        sc_if = xsc_if;
        ifp = sc_if->sk_ifp;
        mii = device_get_softc(sc_if->sk_miibus);

        if (!(if_getflags(ifp) & IFF_UP))
                return;

        if (sc_if->sk_phytype == SK_PHYTYPE_BCOM) {
                sk_intr_bcom(sc_if);
                return;
        }

        /*
         * According to SysKonnect, the correct way to verify that
         * the link has come back up is to poll bit 0 of the GPIO
         * register three times. This pin has the signal from the
         * link_sync pin connected to it; if we read the same link
         * state 3 times in a row, we know the link is up.
         */
        for (i = 0; i < 3; i++) {
                if (SK_XM_READ_2(sc_if, XM_GPIO) & XM_GPIO_GP0_SET)
                        break;
        }

        if (i != 3) {
                callout_reset(&sc_if->sk_tick_ch, hz, sk_tick, sc_if);
                return;
        }

        /* Turn the GP0 interrupt back on. */
        SK_XM_CLRBIT_2(sc_if, XM_IMR, XM_IMR_GP0_SET);
        SK_XM_READ_2(sc_if, XM_ISR);
        mii_tick(mii);
        callout_stop(&sc_if->sk_tick_ch);
}

static void
sk_yukon_tick(void *xsc_if)
{
        struct sk_if_softc      *sc_if;
        struct mii_data         *mii;

        sc_if = xsc_if;
        mii = device_get_softc(sc_if->sk_miibus);

        mii_tick(mii);
        callout_reset(&sc_if->sk_tick_ch, hz, sk_yukon_tick, sc_if);
}

static void
sk_intr_bcom(struct sk_if_softc *sc_if)
{
        struct mii_data         *mii;
        if_t                    ifp;
        int                     status;
        mii = device_get_softc(sc_if->sk_miibus);
        ifp = sc_if->sk_ifp;

        SK_XM_CLRBIT_2(sc_if, XM_MMUCMD, XM_MMUCMD_TX_ENB|XM_MMUCMD_RX_ENB);

        /*
         * Read the PHY interrupt register to make sure
         * we clear any pending interrupts.
         */
        status = sk_xmac_miibus_readreg(sc_if, SK_PHYADDR_BCOM, BRGPHY_MII_ISR);

        if (!(if_getdrvflags(ifp) & IFF_DRV_RUNNING)) {
                sk_init_xmac(sc_if);
                return;
        }

        if (status & (BRGPHY_ISR_LNK_CHG|BRGPHY_ISR_AN_PR)) {
                int                     lstat;
                lstat = sk_xmac_miibus_readreg(sc_if, SK_PHYADDR_BCOM,
                    BRGPHY_MII_AUXSTS);

                if (!(lstat & BRGPHY_AUXSTS_LINK) && sc_if->sk_link) {
                        mii_mediachg(mii);
                        /* Turn off the link LED. */
                        SK_IF_WRITE_1(sc_if, 0,
                            SK_LINKLED1_CTL, SK_LINKLED_OFF);
                        sc_if->sk_link = 0;
                } else if (status & BRGPHY_ISR_LNK_CHG) {
                        sk_xmac_miibus_writereg(sc_if, SK_PHYADDR_BCOM,
                            BRGPHY_MII_IMR, 0xFF00);
                        mii_tick(mii);
                        sc_if->sk_link = 1;
                        /* Turn on the link LED. */
                        SK_IF_WRITE_1(sc_if, 0, SK_LINKLED1_CTL,
                            SK_LINKLED_ON|SK_LINKLED_LINKSYNC_OFF|
                            SK_LINKLED_BLINK_OFF);
                } else {
                        mii_tick(mii);
                        callout_reset(&sc_if->sk_tick_ch, hz, sk_tick, sc_if);
                }
        }

        SK_XM_SETBIT_2(sc_if, XM_MMUCMD, XM_MMUCMD_TX_ENB|XM_MMUCMD_RX_ENB);

        return;
}

static void
sk_intr_xmac(struct sk_if_softc *sc_if)
{
        u_int16_t               status;

        status = SK_XM_READ_2(sc_if, XM_ISR);

        /*
         * Link has gone down. Start MII tick timeout to
         * watch for link resync.
         */
        if (sc_if->sk_phytype == SK_PHYTYPE_XMAC) {
                if (status & XM_ISR_GP0_SET) {
                        SK_XM_SETBIT_2(sc_if, XM_IMR, XM_IMR_GP0_SET);
                        callout_reset(&sc_if->sk_tick_ch, hz, sk_tick, sc_if);
                }

                if (status & XM_ISR_AUTONEG_DONE) {
                        callout_reset(&sc_if->sk_tick_ch, hz, sk_tick, sc_if);
                }
        }

        if (status & XM_IMR_TX_UNDERRUN)
                SK_XM_SETBIT_4(sc_if, XM_MODE, XM_MODE_FLUSH_TXFIFO);

        if (status & XM_IMR_RX_OVERRUN)
                SK_XM_SETBIT_4(sc_if, XM_MODE, XM_MODE_FLUSH_RXFIFO);

        status = SK_XM_READ_2(sc_if, XM_ISR);

        return;
}

static void
sk_intr_yukon(struct sk_if_softc *sc_if)
{
        u_int8_t status;

        status = SK_IF_READ_1(sc_if, 0, SK_GMAC_ISR);
        /* RX overrun */
        if ((status & SK_GMAC_INT_RX_OVER) != 0) {
                SK_IF_WRITE_1(sc_if, 0, SK_RXMF1_CTRL_TEST,
                    SK_RFCTL_RX_FIFO_OVER);
        }
        /* TX underrun */
        if ((status & SK_GMAC_INT_TX_UNDER) != 0) {
                SK_IF_WRITE_1(sc_if, 0, SK_RXMF1_CTRL_TEST,
                    SK_TFCTL_TX_FIFO_UNDER);
        }
}

static void
sk_intr(void *xsc)
{
        struct sk_softc         *sc = xsc;
        struct sk_if_softc      *sc_if0, *sc_if1;
        if_t                    ifp0 = NULL, ifp1 = NULL;
        u_int32_t               status;

        SK_LOCK(sc);

        status = CSR_READ_4(sc, SK_ISSR);
        if (status == 0 || status == 0xffffffff || sc->sk_suspended)
                goto done_locked;

        sc_if0 = sc->sk_if[SK_PORT_A];
        sc_if1 = sc->sk_if[SK_PORT_B];

        if (sc_if0 != NULL)
                ifp0 = sc_if0->sk_ifp;
        if (sc_if1 != NULL)
                ifp1 = sc_if1->sk_ifp;

        for (; (status &= sc->sk_intrmask) != 0;) {
                /* Handle receive interrupts first. */
                if (status & SK_ISR_RX1_EOF) {
                        if (if_getmtu(ifp0) > SK_MAX_FRAMELEN)
                                sk_jumbo_rxeof(sc_if0);
                        else
                                sk_rxeof(sc_if0);
                        CSR_WRITE_4(sc, SK_BMU_RX_CSR0,
                            SK_RXBMU_CLR_IRQ_EOF|SK_RXBMU_RX_START);
                }
                if (status & SK_ISR_RX2_EOF) {
                        if (if_getflags(ifp1) > SK_MAX_FRAMELEN)
                                sk_jumbo_rxeof(sc_if1);
                        else
                                sk_rxeof(sc_if1);
                        CSR_WRITE_4(sc, SK_BMU_RX_CSR1,
                            SK_RXBMU_CLR_IRQ_EOF|SK_RXBMU_RX_START);
                }

                /* Then transmit interrupts. */
                if (status & SK_ISR_TX1_S_EOF) {
                        sk_txeof(sc_if0);
                        CSR_WRITE_4(sc, SK_BMU_TXS_CSR0, SK_TXBMU_CLR_IRQ_EOF);
                }
                if (status & SK_ISR_TX2_S_EOF) {
                        sk_txeof(sc_if1);
                        CSR_WRITE_4(sc, SK_BMU_TXS_CSR1, SK_TXBMU_CLR_IRQ_EOF);
                }

                /* Then MAC interrupts. */
                if (status & SK_ISR_MAC1 &&
                    if_getdrvflags(ifp0) & IFF_DRV_RUNNING) {
                        if (sc->sk_type == SK_GENESIS)
                                sk_intr_xmac(sc_if0);
                        else
                                sk_intr_yukon(sc_if0);
                }

                if (status & SK_ISR_MAC2 &&
                    if_getdrvflags(ifp1) & IFF_DRV_RUNNING) {
                        if (sc->sk_type == SK_GENESIS)
                                sk_intr_xmac(sc_if1);
                        else
                                sk_intr_yukon(sc_if1);
                }

                if (status & SK_ISR_EXTERNAL_REG) {
                        if (ifp0 != NULL &&
                            sc_if0->sk_phytype == SK_PHYTYPE_BCOM)
                                sk_intr_bcom(sc_if0);
                        if (ifp1 != NULL &&
                            sc_if1->sk_phytype == SK_PHYTYPE_BCOM)
                                sk_intr_bcom(sc_if1);
                }
                status = CSR_READ_4(sc, SK_ISSR);
        }

        CSR_WRITE_4(sc, SK_IMR, sc->sk_intrmask);

        if (ifp0 != NULL && !if_sendq_empty(ifp0))
                sk_start_locked(ifp0);
        if (ifp1 != NULL && !if_sendq_empty(ifp1))
                sk_start_locked(ifp1);

done_locked:
        SK_UNLOCK(sc);
}

static void
sk_init_xmac(struct sk_if_softc *sc_if)
{
        struct sk_softc         *sc;
        if_t                    ifp;
        u_int16_t               eaddr[(ETHER_ADDR_LEN+1)/2];
        static const struct sk_bcom_hack bhack[] = {
        { 0x18, 0x0c20 }, { 0x17, 0x0012 }, { 0x15, 0x1104 }, { 0x17, 0x0013 },
        { 0x15, 0x0404 }, { 0x17, 0x8006 }, { 0x15, 0x0132 }, { 0x17, 0x8006 },
        { 0x15, 0x0232 }, { 0x17, 0x800D }, { 0x15, 0x000F }, { 0x18, 0x0420 },
        { 0, 0 } };

        SK_IF_LOCK_ASSERT(sc_if);

        sc = sc_if->sk_softc;
        ifp = sc_if->sk_ifp;

        /* Unreset the XMAC. */
        SK_IF_WRITE_2(sc_if, 0, SK_TXF1_MACCTL, SK_TXMACCTL_XMAC_UNRESET);
        DELAY(1000);

        /* Reset the XMAC's internal state. */
        SK_XM_SETBIT_2(sc_if, XM_GPIO, XM_GPIO_RESETMAC);

        /* Save the XMAC II revision */
        sc_if->sk_xmac_rev = XM_XMAC_REV(SK_XM_READ_4(sc_if, XM_DEVID));

        /*
         * Perform additional initialization for external PHYs,
         * namely for the 1000baseTX cards that use the XMAC's
         * GMII mode.
         */
        if (sc_if->sk_phytype == SK_PHYTYPE_BCOM) {
                int                     i = 0;
                u_int32_t               val;

                /* Take PHY out of reset. */
                val = sk_win_read_4(sc, SK_GPIO);
                if (sc_if->sk_port == SK_PORT_A)
                        val |= SK_GPIO_DIR0|SK_GPIO_DAT0;
                else
                        val |= SK_GPIO_DIR2|SK_GPIO_DAT2;
                sk_win_write_4(sc, SK_GPIO, val);

                /* Enable GMII mode on the XMAC. */
                SK_XM_SETBIT_2(sc_if, XM_HWCFG, XM_HWCFG_GMIIMODE);

                sk_xmac_miibus_writereg(sc_if, SK_PHYADDR_BCOM,
                    BRGPHY_MII_BMCR, BRGPHY_BMCR_RESET);
                DELAY(10000);
                sk_xmac_miibus_writereg(sc_if, SK_PHYADDR_BCOM,
                    BRGPHY_MII_IMR, 0xFFF0);

                /*
                 * Early versions of the BCM5400 apparently have
                 * a bug that requires them to have their reserved
                 * registers initialized to some magic values. I don't
                 * know what the numbers do, I'm just the messenger.
                 */
                if (sk_xmac_miibus_readreg(sc_if, SK_PHYADDR_BCOM, 0x03)
                    == 0x6041) {
                        while(bhack[i].reg) {
                                sk_xmac_miibus_writereg(sc_if, SK_PHYADDR_BCOM,
                                    bhack[i].reg, bhack[i].val);
                                i++;
                        }
                }
        }

        /* Set station address */
        bcopy(if_getlladdr(sc_if->sk_ifp), eaddr, ETHER_ADDR_LEN);
        SK_XM_WRITE_2(sc_if, XM_PAR0, eaddr[0]);
        SK_XM_WRITE_2(sc_if, XM_PAR1, eaddr[1]);
        SK_XM_WRITE_2(sc_if, XM_PAR2, eaddr[2]);
        SK_XM_SETBIT_4(sc_if, XM_MODE, XM_MODE_RX_USE_STATION);

        if (if_getflags(ifp) & IFF_BROADCAST) {
                SK_XM_CLRBIT_4(sc_if, XM_MODE, XM_MODE_RX_NOBROAD);
        } else {
                SK_XM_SETBIT_4(sc_if, XM_MODE, XM_MODE_RX_NOBROAD);
        }

        /* We don't need the FCS appended to the packet. */
        SK_XM_SETBIT_2(sc_if, XM_RXCMD, XM_RXCMD_STRIPFCS);

        /* We want short frames padded to 60 bytes. */
        SK_XM_SETBIT_2(sc_if, XM_TXCMD, XM_TXCMD_AUTOPAD);

        /*
         * Enable the reception of all error frames. This is is
         * a necessary evil due to the design of the XMAC. The
         * XMAC's receive FIFO is only 8K in size, however jumbo
         * frames can be up to 9000 bytes in length. When bad
         * frame filtering is enabled, the XMAC's RX FIFO operates
         * in 'store and forward' mode. For this to work, the
         * entire frame has to fit into the FIFO, but that means
         * that jumbo frames larger than 8192 bytes will be
         * truncated. Disabling all bad frame filtering causes
         * the RX FIFO to operate in streaming mode, in which
         * case the XMAC will start transferring frames out of the
         * RX FIFO as soon as the FIFO threshold is reached.
         */
        if (if_getmtu(ifp) > SK_MAX_FRAMELEN) {
                SK_XM_SETBIT_4(sc_if, XM_MODE, XM_MODE_RX_BADFRAMES|
                    XM_MODE_RX_GIANTS|XM_MODE_RX_RUNTS|XM_MODE_RX_CRCERRS|
                    XM_MODE_RX_INRANGELEN);
                SK_XM_SETBIT_2(sc_if, XM_RXCMD, XM_RXCMD_BIGPKTOK);
        } else
                SK_XM_CLRBIT_2(sc_if, XM_RXCMD, XM_RXCMD_BIGPKTOK);

        /*
         * Bump up the transmit threshold. This helps hold off transmit
         * underruns when we're blasting traffic from both ports at once.
         */
        SK_XM_WRITE_2(sc_if, XM_TX_REQTHRESH, SK_XM_TX_FIFOTHRESH);

        /* Set Rx filter */
        sk_rxfilter_genesis(sc_if);

        /* Clear and enable interrupts */
        SK_XM_READ_2(sc_if, XM_ISR);
        if (sc_if->sk_phytype == SK_PHYTYPE_XMAC)
                SK_XM_WRITE_2(sc_if, XM_IMR, XM_INTRS);
        else
                SK_XM_WRITE_2(sc_if, XM_IMR, 0xFFFF);

        /* Configure MAC arbiter */
        switch(sc_if->sk_xmac_rev) {
        case XM_XMAC_REV_B2:
                sk_win_write_1(sc, SK_RCINIT_RX1, SK_RCINIT_XMAC_B2);
                sk_win_write_1(sc, SK_RCINIT_TX1, SK_RCINIT_XMAC_B2);
                sk_win_write_1(sc, SK_RCINIT_RX2, SK_RCINIT_XMAC_B2);
                sk_win_write_1(sc, SK_RCINIT_TX2, SK_RCINIT_XMAC_B2);
                sk_win_write_1(sc, SK_MINIT_RX1, SK_MINIT_XMAC_B2);
                sk_win_write_1(sc, SK_MINIT_TX1, SK_MINIT_XMAC_B2);
                sk_win_write_1(sc, SK_MINIT_RX2, SK_MINIT_XMAC_B2);
                sk_win_write_1(sc, SK_MINIT_TX2, SK_MINIT_XMAC_B2);
                sk_win_write_1(sc, SK_RECOVERY_CTL, SK_RECOVERY_XMAC_B2);
                break;
        case XM_XMAC_REV_C1:
                sk_win_write_1(sc, SK_RCINIT_RX1, SK_RCINIT_XMAC_C1);
                sk_win_write_1(sc, SK_RCINIT_TX1, SK_RCINIT_XMAC_C1);
                sk_win_write_1(sc, SK_RCINIT_RX2, SK_RCINIT_XMAC_C1);
                sk_win_write_1(sc, SK_RCINIT_TX2, SK_RCINIT_XMAC_C1);
                sk_win_write_1(sc, SK_MINIT_RX1, SK_MINIT_XMAC_C1);
                sk_win_write_1(sc, SK_MINIT_TX1, SK_MINIT_XMAC_C1);
                sk_win_write_1(sc, SK_MINIT_RX2, SK_MINIT_XMAC_C1);
                sk_win_write_1(sc, SK_MINIT_TX2, SK_MINIT_XMAC_C1);
                sk_win_write_1(sc, SK_RECOVERY_CTL, SK_RECOVERY_XMAC_B2);
                break;
        default:
                break;
        }
        sk_win_write_2(sc, SK_MACARB_CTL,
            SK_MACARBCTL_UNRESET|SK_MACARBCTL_FASTOE_OFF);

        sc_if->sk_link = 1;

        return;
}

static void
sk_init_yukon(struct sk_if_softc *sc_if)
{
        u_int32_t               phy, v;
        u_int16_t               reg;
        struct sk_softc         *sc;
        if_t                    ifp;
        u_int8_t                *eaddr;
        int                     i;

        SK_IF_LOCK_ASSERT(sc_if);

        sc = sc_if->sk_softc;
        ifp = sc_if->sk_ifp;

        if (sc->sk_type == SK_YUKON_LITE &&
            sc->sk_rev >= SK_YUKON_LITE_REV_A3) {
                /*
                 * Workaround code for COMA mode, set PHY reset.
                 * Otherwise it will not correctly take chip out of
                 * powerdown (coma)
                 */
                v = sk_win_read_4(sc, SK_GPIO);
                v |= SK_GPIO_DIR9 | SK_GPIO_DAT9;
                sk_win_write_4(sc, SK_GPIO, v);
        }

        /* GMAC and GPHY Reset */
        SK_IF_WRITE_4(sc_if, 0, SK_GPHY_CTRL, SK_GPHY_RESET_SET);
        SK_IF_WRITE_4(sc_if, 0, SK_GMAC_CTRL, SK_GMAC_RESET_SET);
        DELAY(1000);

        if (sc->sk_type == SK_YUKON_LITE &&
            sc->sk_rev >= SK_YUKON_LITE_REV_A3) {
                /*
                 * Workaround code for COMA mode, clear PHY reset
                 */
                v = sk_win_read_4(sc, SK_GPIO);
                v |= SK_GPIO_DIR9;
                v &= ~SK_GPIO_DAT9;
                sk_win_write_4(sc, SK_GPIO, v);
        }

        phy = SK_GPHY_INT_POL_HI | SK_GPHY_DIS_FC | SK_GPHY_DIS_SLEEP |
                SK_GPHY_ENA_XC | SK_GPHY_ANEG_ALL | SK_GPHY_ENA_PAUSE;

        if (sc->sk_coppertype)
                phy |= SK_GPHY_COPPER;
        else
                phy |= SK_GPHY_FIBER;

        SK_IF_WRITE_4(sc_if, 0, SK_GPHY_CTRL, phy | SK_GPHY_RESET_SET);
        DELAY(1000);
        SK_IF_WRITE_4(sc_if, 0, SK_GPHY_CTRL, phy | SK_GPHY_RESET_CLEAR);
        SK_IF_WRITE_4(sc_if, 0, SK_GMAC_CTRL, SK_GMAC_LOOP_OFF |
                      SK_GMAC_PAUSE_ON | SK_GMAC_RESET_CLEAR);

        /* unused read of the interrupt source register */
        SK_IF_READ_2(sc_if, 0, SK_GMAC_ISR);

        reg = SK_YU_READ_2(sc_if, YUKON_PAR);

        /* MIB Counter Clear Mode set */
        reg |= YU_PAR_MIB_CLR;
        SK_YU_WRITE_2(sc_if, YUKON_PAR, reg);

        /* MIB Counter Clear Mode clear */
        reg &= ~YU_PAR_MIB_CLR;
        SK_YU_WRITE_2(sc_if, YUKON_PAR, reg);

        /* receive control reg */
        SK_YU_WRITE_2(sc_if, YUKON_RCR, YU_RCR_CRCR);

        /* transmit parameter register */
        SK_YU_WRITE_2(sc_if, YUKON_TPR, YU_TPR_JAM_LEN(0x3) |
                      YU_TPR_JAM_IPG(0xb) | YU_TPR_JAM2DATA_IPG(0x1a) );

        /* serial mode register */
        reg = YU_SMR_DATA_BLIND(0x1c) | YU_SMR_MFL_VLAN | YU_SMR_IPG_DATA(0x1e);
        if (if_getmtu(ifp) > SK_MAX_FRAMELEN)
                reg |= YU_SMR_MFL_JUMBO;
        SK_YU_WRITE_2(sc_if, YUKON_SMR, reg);

        /* Setup Yukon's station address */
        eaddr = if_getlladdr(sc_if->sk_ifp);
        for (i = 0; i < 3; i++)
                SK_YU_WRITE_2(sc_if, SK_MAC0_0 + i * 4,
                    eaddr[i * 2] | eaddr[i * 2 + 1] << 8);
        /* Set GMAC source address of flow control. */
        for (i = 0; i < 3; i++)
                SK_YU_WRITE_2(sc_if, YUKON_SAL1 + i * 4,
                    eaddr[i * 2] | eaddr[i * 2 + 1] << 8);
        /* Set GMAC virtual address. */
        for (i = 0; i < 3; i++)
                SK_YU_WRITE_2(sc_if, YUKON_SAL2 + i * 4,
                    eaddr[i * 2] | eaddr[i * 2 + 1] << 8);

        /* Set Rx filter */
        sk_rxfilter_yukon(sc_if);

        /* enable interrupt mask for counter overflows */
        SK_YU_WRITE_2(sc_if, YUKON_TIMR, 0);
        SK_YU_WRITE_2(sc_if, YUKON_RIMR, 0);
        SK_YU_WRITE_2(sc_if, YUKON_TRIMR, 0);

        /* Configure RX MAC FIFO Flush Mask */
        v = YU_RXSTAT_FOFL | YU_RXSTAT_CRCERR | YU_RXSTAT_MIIERR |
            YU_RXSTAT_BADFC | YU_RXSTAT_GOODFC | YU_RXSTAT_RUNT |
            YU_RXSTAT_JABBER;
        SK_IF_WRITE_2(sc_if, 0, SK_RXMF1_FLUSH_MASK, v);

        /* Disable RX MAC FIFO Flush for YUKON-Lite Rev. A0 only */
        if (sc->sk_type == SK_YUKON_LITE && sc->sk_rev == SK_YUKON_LITE_REV_A0)
                v = SK_TFCTL_OPERATION_ON;
        else
                v = SK_TFCTL_OPERATION_ON | SK_RFCTL_FIFO_FLUSH_ON;
        /* Configure RX MAC FIFO */
        SK_IF_WRITE_1(sc_if, 0, SK_RXMF1_CTRL_TEST, SK_RFCTL_RESET_CLEAR);
        SK_IF_WRITE_2(sc_if, 0, SK_RXMF1_CTRL_TEST, v);

        /* Increase flush threshould to 64 bytes */
        SK_IF_WRITE_2(sc_if, 0, SK_RXMF1_FLUSH_THRESHOLD,
            SK_RFCTL_FIFO_THRESHOLD + 1);

        /* Configure TX MAC FIFO */
        SK_IF_WRITE_1(sc_if, 0, SK_TXMF1_CTRL_TEST, SK_TFCTL_RESET_CLEAR);
        SK_IF_WRITE_2(sc_if, 0, SK_TXMF1_CTRL_TEST, SK_TFCTL_OPERATION_ON);
}

/*
 * Note that to properly initialize any part of the GEnesis chip,
 * you first have to take it out of reset mode.
 */
static void
sk_init(void *xsc)
{
        struct sk_if_softc      *sc_if = xsc;

        SK_IF_LOCK(sc_if);
        sk_init_locked(sc_if);
        SK_IF_UNLOCK(sc_if);

        return;
}

static void
sk_init_locked(struct sk_if_softc *sc_if)
{
        struct sk_softc         *sc;
        if_t                    ifp;
        struct mii_data         *mii;
        u_int16_t               reg;
        u_int32_t               imr;
        int                     error;

        SK_IF_LOCK_ASSERT(sc_if);

        ifp = sc_if->sk_ifp;
        sc = sc_if->sk_softc;
        mii = device_get_softc(sc_if->sk_miibus);

        if (if_getdrvflags(ifp) & IFF_DRV_RUNNING)
                return;

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

        if (sc->sk_type == SK_GENESIS) {
                /* Configure LINK_SYNC LED */
                SK_IF_WRITE_1(sc_if, 0, SK_LINKLED1_CTL, SK_LINKLED_ON);
                SK_IF_WRITE_1(sc_if, 0, SK_LINKLED1_CTL,
                        SK_LINKLED_LINKSYNC_ON);

                /* Configure RX LED */
                SK_IF_WRITE_1(sc_if, 0, SK_RXLED1_CTL,
                        SK_RXLEDCTL_COUNTER_START);

                /* Configure TX LED */
                SK_IF_WRITE_1(sc_if, 0, SK_TXLED1_CTL,
                        SK_TXLEDCTL_COUNTER_START);
        }

        /*
         * Configure descriptor poll timer
         *
         * SK-NET GENESIS data sheet says that possibility of losing Start
         * transmit command due to CPU/cache related interim storage problems
         * under certain conditions. The document recommends a polling
         * mechanism to send a Start transmit command to initiate transfer
         * of ready descriptors regulary. To cope with this issue sk(4) now
         * enables descriptor poll timer to initiate descriptor processing
         * periodically as defined by SK_DPT_TIMER_MAX. However sk(4) still
         * issue SK_TXBMU_TX_START to Tx BMU to get fast execution of Tx
         * command instead of waiting for next descriptor polling time.
         * The same rule may apply to Rx side too but it seems that is not
         * needed at the moment.
         * Since sk(4) uses descriptor polling as a last resort there is no
         * need to set smaller polling time than maximum allowable one.
         */
        SK_IF_WRITE_4(sc_if, 0, SK_DPT_INIT, SK_DPT_TIMER_MAX);

        /* Configure I2C registers */

        /* Configure XMAC(s) */
        switch (sc->sk_type) {
        case SK_GENESIS:
                sk_init_xmac(sc_if);
                break;
        case SK_YUKON:
        case SK_YUKON_LITE:
        case SK_YUKON_LP:
                sk_init_yukon(sc_if);
                break;
        }
        mii_mediachg(mii);

        if (sc->sk_type == SK_GENESIS) {
                /* Configure MAC FIFOs */
                SK_IF_WRITE_4(sc_if, 0, SK_RXF1_CTL, SK_FIFO_UNRESET);
                SK_IF_WRITE_4(sc_if, 0, SK_RXF1_END, SK_FIFO_END);
                SK_IF_WRITE_4(sc_if, 0, SK_RXF1_CTL, SK_FIFO_ON);

                SK_IF_WRITE_4(sc_if, 0, SK_TXF1_CTL, SK_FIFO_UNRESET);
                SK_IF_WRITE_4(sc_if, 0, SK_TXF1_END, SK_FIFO_END);
                SK_IF_WRITE_4(sc_if, 0, SK_TXF1_CTL, SK_FIFO_ON);
        }

        /* Configure transmit arbiter(s) */
        SK_IF_WRITE_1(sc_if, 0, SK_TXAR1_COUNTERCTL,
            SK_TXARCTL_ON|SK_TXARCTL_FSYNC_ON);

        /* Configure RAMbuffers */
        SK_IF_WRITE_4(sc_if, 0, SK_RXRB1_CTLTST, SK_RBCTL_UNRESET);
        SK_IF_WRITE_4(sc_if, 0, SK_RXRB1_START, sc_if->sk_rx_ramstart);
        SK_IF_WRITE_4(sc_if, 0, SK_RXRB1_WR_PTR, sc_if->sk_rx_ramstart);
        SK_IF_WRITE_4(sc_if, 0, SK_RXRB1_RD_PTR, sc_if->sk_rx_ramstart);
        SK_IF_WRITE_4(sc_if, 0, SK_RXRB1_END, sc_if->sk_rx_ramend);
        SK_IF_WRITE_4(sc_if, 0, SK_RXRB1_CTLTST, SK_RBCTL_ON);

        SK_IF_WRITE_4(sc_if, 1, SK_TXRBS1_CTLTST, SK_RBCTL_UNRESET);
        SK_IF_WRITE_4(sc_if, 1, SK_TXRBS1_CTLTST, SK_RBCTL_STORENFWD_ON);
        SK_IF_WRITE_4(sc_if, 1, SK_TXRBS1_START, sc_if->sk_tx_ramstart);
        SK_IF_WRITE_4(sc_if, 1, SK_TXRBS1_WR_PTR, sc_if->sk_tx_ramstart);
        SK_IF_WRITE_4(sc_if, 1, SK_TXRBS1_RD_PTR, sc_if->sk_tx_ramstart);
        SK_IF_WRITE_4(sc_if, 1, SK_TXRBS1_END, sc_if->sk_tx_ramend);
        SK_IF_WRITE_4(sc_if, 1, SK_TXRBS1_CTLTST, SK_RBCTL_ON);

        /* Configure BMUs */
        SK_IF_WRITE_4(sc_if, 0, SK_RXQ1_BMU_CSR, SK_RXBMU_ONLINE);
        if (if_getmtu(ifp) > SK_MAX_FRAMELEN) {
                SK_IF_WRITE_4(sc_if, 0, SK_RXQ1_CURADDR_LO,
                    SK_ADDR_LO(SK_JUMBO_RX_RING_ADDR(sc_if, 0)));
                SK_IF_WRITE_4(sc_if, 0, SK_RXQ1_CURADDR_HI,
                    SK_ADDR_HI(SK_JUMBO_RX_RING_ADDR(sc_if, 0)));
        } else {
                SK_IF_WRITE_4(sc_if, 0, SK_RXQ1_CURADDR_LO,
                    SK_ADDR_LO(SK_RX_RING_ADDR(sc_if, 0)));
                SK_IF_WRITE_4(sc_if, 0, SK_RXQ1_CURADDR_HI,
                    SK_ADDR_HI(SK_RX_RING_ADDR(sc_if, 0)));
        }

        SK_IF_WRITE_4(sc_if, 1, SK_TXQS1_BMU_CSR, SK_TXBMU_ONLINE);
        SK_IF_WRITE_4(sc_if, 1, SK_TXQS1_CURADDR_LO,
            SK_ADDR_LO(SK_TX_RING_ADDR(sc_if, 0)));
        SK_IF_WRITE_4(sc_if, 1, SK_TXQS1_CURADDR_HI,
            SK_ADDR_HI(SK_TX_RING_ADDR(sc_if, 0)));

        /* Init descriptors */
        if (if_getmtu(ifp) > SK_MAX_FRAMELEN)
                error = sk_init_jumbo_rx_ring(sc_if);
        else
                error = sk_init_rx_ring(sc_if);
        if (error != 0) {
                device_printf(sc_if->sk_if_dev,
                    "initialization failed: no memory for rx buffers\n");
                sk_stop(sc_if);
                return;
        }
        sk_init_tx_ring(sc_if);

        /* Set interrupt moderation if changed via sysctl. */
        imr = sk_win_read_4(sc, SK_IMTIMERINIT);
        if (imr != SK_IM_USECS(sc->sk_int_mod, sc->sk_int_ticks)) {
                sk_win_write_4(sc, SK_IMTIMERINIT, SK_IM_USECS(sc->sk_int_mod,
                    sc->sk_int_ticks));
                if (bootverbose)
                        device_printf(sc_if->sk_if_dev,
                            "interrupt moderation is %d us.\n",
                            sc->sk_int_mod);
        }

        /* Configure interrupt handling */
        CSR_READ_4(sc, SK_ISSR);
        if (sc_if->sk_port == SK_PORT_A)
                sc->sk_intrmask |= SK_INTRS1;
        else
                sc->sk_intrmask |= SK_INTRS2;

        sc->sk_intrmask |= SK_ISR_EXTERNAL_REG;

        CSR_WRITE_4(sc, SK_IMR, sc->sk_intrmask);

        /* Start BMUs. */
        SK_IF_WRITE_4(sc_if, 0, SK_RXQ1_BMU_CSR, SK_RXBMU_RX_START);

        switch(sc->sk_type) {
        case SK_GENESIS:
                /* Enable XMACs TX and RX state machines */
                SK_XM_CLRBIT_2(sc_if, XM_MMUCMD, XM_MMUCMD_IGNPAUSE);
                SK_XM_SETBIT_2(sc_if, XM_MMUCMD, XM_MMUCMD_TX_ENB|XM_MMUCMD_RX_ENB);
                break;
        case SK_YUKON:
        case SK_YUKON_LITE:
        case SK_YUKON_LP:
                reg = SK_YU_READ_2(sc_if, YUKON_GPCR);
                reg |= YU_GPCR_TXEN | YU_GPCR_RXEN;
#if 0
                /* XXX disable 100Mbps and full duplex mode? */
                reg &= ~(YU_GPCR_SPEED | YU_GPCR_DPLX_DIS);
#endif
                SK_YU_WRITE_2(sc_if, YUKON_GPCR, reg);
        }

        /* Activate descriptor polling timer */
        SK_IF_WRITE_4(sc_if, 0, SK_DPT_TIMER_CTRL, SK_DPT_TCTL_START);
        /* start transfer of Tx descriptors */
        CSR_WRITE_4(sc, sc_if->sk_tx_bmu, SK_TXBMU_TX_START);

        if_setdrvflagbits(ifp, IFF_DRV_RUNNING, 0);
        if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);

        switch (sc->sk_type) {
        case SK_YUKON:
        case SK_YUKON_LITE:
        case SK_YUKON_LP:
                callout_reset(&sc_if->sk_tick_ch, hz, sk_yukon_tick, sc_if);
                break;
        }

        callout_reset(&sc_if->sk_watchdog_ch, hz, sk_watchdog, ifp);

        return;
}

static void
sk_stop(struct sk_if_softc *sc_if)
{
        int                     i;
        struct sk_softc         *sc;
        struct sk_txdesc        *txd;
        struct sk_rxdesc        *rxd;
        struct sk_rxdesc        *jrxd;
        if_t                    ifp;
        u_int32_t               val;

        SK_IF_LOCK_ASSERT(sc_if);
        sc = sc_if->sk_softc;
        ifp = sc_if->sk_ifp;

        callout_stop(&sc_if->sk_tick_ch);
        callout_stop(&sc_if->sk_watchdog_ch);

        /* stop Tx descriptor polling timer */
        SK_IF_WRITE_4(sc_if, 0, SK_DPT_TIMER_CTRL, SK_DPT_TCTL_STOP);
        /* stop transfer of Tx descriptors */
        CSR_WRITE_4(sc, sc_if->sk_tx_bmu, SK_TXBMU_TX_STOP);
        for (i = 0; i < SK_TIMEOUT; i++) {
                val = CSR_READ_4(sc, sc_if->sk_tx_bmu);
                if ((val & SK_TXBMU_TX_STOP) == 0)
                        break;
                DELAY(1);
        }
        if (i == SK_TIMEOUT)
                device_printf(sc_if->sk_if_dev,
                    "can not stop transfer of Tx descriptor\n");
        /* stop transfer of Rx descriptors */
        SK_IF_WRITE_4(sc_if, 0, SK_RXQ1_BMU_CSR, SK_RXBMU_RX_STOP);
        for (i = 0; i < SK_TIMEOUT; i++) {
                val = SK_IF_READ_4(sc_if, 0, SK_RXQ1_BMU_CSR);
                if ((val & SK_RXBMU_RX_STOP) == 0)
                        break;
                DELAY(1);
        }
        if (i == SK_TIMEOUT)
                device_printf(sc_if->sk_if_dev,
                    "can not stop transfer of Rx descriptor\n");

        if (sc_if->sk_phytype == SK_PHYTYPE_BCOM) {
                /* Put PHY back into reset. */
                val = sk_win_read_4(sc, SK_GPIO);
                if (sc_if->sk_port == SK_PORT_A) {
                        val |= SK_GPIO_DIR0;
                        val &= ~SK_GPIO_DAT0;
                } else {
                        val |= SK_GPIO_DIR2;
                        val &= ~SK_GPIO_DAT2;
                }
                sk_win_write_4(sc, SK_GPIO, val);
        }

        /* Turn off various components of this interface. */
        SK_XM_SETBIT_2(sc_if, XM_GPIO, XM_GPIO_RESETMAC);
        switch (sc->sk_type) {
        case SK_GENESIS:
                SK_IF_WRITE_2(sc_if, 0, SK_TXF1_MACCTL, SK_TXMACCTL_XMAC_RESET);
                SK_IF_WRITE_4(sc_if, 0, SK_RXF1_CTL, SK_FIFO_RESET);
                break;
        case SK_YUKON:
        case SK_YUKON_LITE:
        case SK_YUKON_LP:
                SK_IF_WRITE_1(sc_if,0, SK_RXMF1_CTRL_TEST, SK_RFCTL_RESET_SET);
                SK_IF_WRITE_1(sc_if,0, SK_TXMF1_CTRL_TEST, SK_TFCTL_RESET_SET);
                break;
        }
        SK_IF_WRITE_4(sc_if, 0, SK_RXQ1_BMU_CSR, SK_RXBMU_OFFLINE);
        SK_IF_WRITE_4(sc_if, 0, SK_RXRB1_CTLTST, SK_RBCTL_RESET|SK_RBCTL_OFF);
        SK_IF_WRITE_4(sc_if, 1, SK_TXQS1_BMU_CSR, SK_TXBMU_OFFLINE);
        SK_IF_WRITE_4(sc_if, 1, SK_TXRBS1_CTLTST, SK_RBCTL_RESET|SK_RBCTL_OFF);
        SK_IF_WRITE_1(sc_if, 0, SK_TXAR1_COUNTERCTL, SK_TXARCTL_OFF);
        SK_IF_WRITE_1(sc_if, 0, SK_RXLED1_CTL, SK_RXLEDCTL_COUNTER_STOP);
        SK_IF_WRITE_1(sc_if, 0, SK_TXLED1_CTL, SK_RXLEDCTL_COUNTER_STOP);
        SK_IF_WRITE_1(sc_if, 0, SK_LINKLED1_CTL, SK_LINKLED_OFF);
        SK_IF_WRITE_1(sc_if, 0, SK_LINKLED1_CTL, SK_LINKLED_LINKSYNC_OFF);

        /* Disable interrupts */
        if (sc_if->sk_port == SK_PORT_A)
                sc->sk_intrmask &= ~SK_INTRS1;
        else
                sc->sk_intrmask &= ~SK_INTRS2;
        CSR_WRITE_4(sc, SK_IMR, sc->sk_intrmask);

        SK_XM_READ_2(sc_if, XM_ISR);
        SK_XM_WRITE_2(sc_if, XM_IMR, 0xFFFF);

        /* Free RX and TX mbufs still in the queues. */
        for (i = 0; i < SK_RX_RING_CNT; i++) {
                rxd = &sc_if->sk_cdata.sk_rxdesc[i];
                if (rxd->rx_m != NULL) {
                        bus_dmamap_sync(sc_if->sk_cdata.sk_rx_tag,
                            rxd->rx_dmamap, BUS_DMASYNC_POSTREAD);
                        bus_dmamap_unload(sc_if->sk_cdata.sk_rx_tag,
                            rxd->rx_dmamap);
                        m_freem(rxd->rx_m);
                        rxd->rx_m = NULL;
                }
        }
        for (i = 0; i < SK_JUMBO_RX_RING_CNT; i++) {
                jrxd = &sc_if->sk_cdata.sk_jumbo_rxdesc[i];
                if (jrxd->rx_m != NULL) {
                        bus_dmamap_sync(sc_if->sk_cdata.sk_jumbo_rx_tag,
                            jrxd->rx_dmamap, BUS_DMASYNC_POSTREAD);
                        bus_dmamap_unload(sc_if->sk_cdata.sk_jumbo_rx_tag,
                            jrxd->rx_dmamap);
                        m_freem(jrxd->rx_m);
                        jrxd->rx_m = NULL;
                }
        }
        for (i = 0; i < SK_TX_RING_CNT; i++) {
                txd = &sc_if->sk_cdata.sk_txdesc[i];
                if (txd->tx_m != NULL) {
                        bus_dmamap_sync(sc_if->sk_cdata.sk_tx_tag,
                            txd->tx_dmamap, BUS_DMASYNC_POSTWRITE);
                        bus_dmamap_unload(sc_if->sk_cdata.sk_tx_tag,
                            txd->tx_dmamap);
                        m_freem(txd->tx_m);
                        txd->tx_m = NULL;
                }
        }

        if_setdrvflagbits(ifp, 0, (IFF_DRV_RUNNING|IFF_DRV_OACTIVE));

        return;
}

static int
sysctl_int_range(SYSCTL_HANDLER_ARGS, int low, int high)
{
        int error, value;

        if (!arg1)
                return (EINVAL);
        value = *(int *)arg1;
        error = sysctl_handle_int(oidp, &value, 0, req);
        if (error || !req->newptr)
                return (error);
        if (value < low || value > high)
                return (EINVAL);
        *(int *)arg1 = value;
        return (0);
}

static int
sysctl_hw_sk_int_mod(SYSCTL_HANDLER_ARGS)
{
        return (sysctl_int_range(oidp, arg1, arg2, req, SK_IM_MIN, SK_IM_MAX));
}