Sync usage with man page.

[netbsd-mini2440.git] / sys / dev / ic / aic6915.c

/*      $NetBSD: aic6915.c,v 1.24 2009/05/12 14:25:17 cegger Exp $      */

/*-
 * Copyright (c) 2001 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Device driver for the Adaptec AIC-6915 (``Starfire'')
 * 10/100 Ethernet controller.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: aic6915.c,v 1.24 2009/05/12 14:25:17 cegger Exp $");

#include "bpfilter.h"

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

#include <uvm/uvm_extern.h>

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

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

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

#include <dev/mii/miivar.h>

#include <dev/ic/aic6915reg.h>
#include <dev/ic/aic6915var.h>

static void     sf_start(struct ifnet *);
static void     sf_watchdog(struct ifnet *);
static int      sf_ioctl(struct ifnet *, u_long, void *);
static int      sf_init(struct ifnet *);
static void     sf_stop(struct ifnet *, int);

static bool     sf_shutdown(device_t, int);

static void     sf_txintr(struct sf_softc *);
static void     sf_rxintr(struct sf_softc *);
static void     sf_stats_update(struct sf_softc *);

static void     sf_reset(struct sf_softc *);
static void     sf_macreset(struct sf_softc *);
static void     sf_rxdrain(struct sf_softc *);
static int      sf_add_rxbuf(struct sf_softc *, int);
static uint8_t  sf_read_eeprom(struct sf_softc *, int);
static void     sf_set_filter(struct sf_softc *);

static int      sf_mii_read(device_t, int, int);
static void     sf_mii_write(device_t, int, int, int);
static void     sf_mii_statchg(device_t);

static void     sf_tick(void *);

#define sf_funcreg_read(sc, reg)                                        \
        bus_space_read_4((sc)->sc_st, (sc)->sc_sh_func, (reg))
#define sf_funcreg_write(sc, reg, val)                                  \
        bus_space_write_4((sc)->sc_st, (sc)->sc_sh_func, (reg), (val))

static inline uint32_t
sf_reg_read(struct sf_softc *sc, bus_addr_t reg)
{

        if (__predict_false(sc->sc_iomapped)) {
                bus_space_write_4(sc->sc_st, sc->sc_sh, SF_IndirectIoAccess,
                    reg);
                return (bus_space_read_4(sc->sc_st, sc->sc_sh,
                    SF_IndirectIoDataPort));
        }

        return (bus_space_read_4(sc->sc_st, sc->sc_sh, reg));
}

static inline void
sf_reg_write(struct sf_softc *sc, bus_addr_t reg, uint32_t val)
{

        if (__predict_false(sc->sc_iomapped)) {
                bus_space_write_4(sc->sc_st, sc->sc_sh, SF_IndirectIoAccess,
                    reg);
                bus_space_write_4(sc->sc_st, sc->sc_sh, SF_IndirectIoDataPort,
                    val);
                return;
        }

        bus_space_write_4(sc->sc_st, sc->sc_sh, reg, val);
}

#define sf_genreg_read(sc, reg)                                         \
        sf_reg_read((sc), (reg) + SF_GENREG_OFFSET)
#define sf_genreg_write(sc, reg, val)                                   \
        sf_reg_write((sc), (reg) + SF_GENREG_OFFSET, (val))

/*
 * sf_attach:
 *
 *      Attach a Starfire interface to the system.
 */
void
sf_attach(struct sf_softc *sc)
{
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;
        int i, rseg, error;
        bus_dma_segment_t seg;
        u_int8_t enaddr[ETHER_ADDR_LEN];

        callout_init(&sc->sc_tick_callout, 0);

        /*
         * If we're I/O mapped, the functional register handle is
         * the same as the base handle.  If we're memory mapped,
         * carve off a chunk of the register space for the functional
         * registers, to save on arithmetic later.
         */
        if (sc->sc_iomapped)
                sc->sc_sh_func = sc->sc_sh;
        else {
                if ((error = bus_space_subregion(sc->sc_st, sc->sc_sh,
                    SF_GENREG_OFFSET, SF_FUNCREG_SIZE, &sc->sc_sh_func)) != 0) {
                        aprint_error_dev(&sc->sc_dev, "unable to sub-region functional "
                            "registers, error = %d\n",
                            error);
                        return;
                }
        }

        /*
         * Initialize the transmit threshold for this interface.  The
         * manual describes the default as 4 * 16 bytes.  We start out
         * at 10 * 16 bytes, to avoid a bunch of initial underruns on
         * several platforms.
         */
        sc->sc_txthresh = 10;

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

        if ((error = bus_dmamem_map(sc->sc_dmat, &seg, rseg,
            sizeof(struct sf_control_data), (void **)&sc->sc_control_data,
            BUS_DMA_NOWAIT|BUS_DMA_COHERENT)) != 0) {
                aprint_error_dev(&sc->sc_dev, "unable to map control data, error = %d\n",
                    error);
                goto fail_1;
        }

        if ((error = bus_dmamap_create(sc->sc_dmat,
            sizeof(struct sf_control_data), 1,
            sizeof(struct sf_control_data), 0, BUS_DMA_NOWAIT,
            &sc->sc_cddmamap)) != 0) {
                aprint_error_dev(&sc->sc_dev, "unable to create control data DMA map, "
                    "error = %d\n", error);
                goto fail_2;
        }

        if ((error = bus_dmamap_load(sc->sc_dmat, sc->sc_cddmamap,
            sc->sc_control_data, sizeof(struct sf_control_data), NULL,
            BUS_DMA_NOWAIT)) != 0) {
                aprint_error_dev(&sc->sc_dev, "unable to load control data DMA map, error = %d\n",
                    error);
                goto fail_3;
        }

        /*
         * Create the transmit buffer DMA maps.
         */
        for (i = 0; i < SF_NTXDESC; i++) {
                if ((error = bus_dmamap_create(sc->sc_dmat, MCLBYTES,
                    SF_NTXFRAGS, MCLBYTES, 0, BUS_DMA_NOWAIT,
                    &sc->sc_txsoft[i].ds_dmamap)) != 0) {
                        aprint_error_dev(&sc->sc_dev, "unable to create tx DMA map %d, "
                            "error = %d\n", i, error);
                        goto fail_4;
                }
        }

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

        /*
         * Reset the chip to a known state.
         */
        sf_reset(sc);

        /*
         * Read the Ethernet address from the EEPROM.
         */
        for (i = 0; i < ETHER_ADDR_LEN; i++)
                enaddr[i] = sf_read_eeprom(sc, (15 + (ETHER_ADDR_LEN - 1)) - i);

        printf("%s: Ethernet address %s\n", device_xname(&sc->sc_dev),
            ether_sprintf(enaddr));

        if (sf_funcreg_read(sc, SF_PciDeviceConfig) & PDC_System64)
                printf("%s: 64-bit PCI slot detected\n", device_xname(&sc->sc_dev));

        /*
         * Initialize our media structures and probe the MII.
         */
        sc->sc_mii.mii_ifp = ifp;
        sc->sc_mii.mii_readreg = sf_mii_read;
        sc->sc_mii.mii_writereg = sf_mii_write;
        sc->sc_mii.mii_statchg = sf_mii_statchg;
        sc->sc_ethercom.ec_mii = &sc->sc_mii;
        ifmedia_init(&sc->sc_mii.mii_media, IFM_IMASK, ether_mediachange,
            ether_mediastatus);
        mii_attach(&sc->sc_dev, &sc->sc_mii, 0xffffffff, MII_PHY_ANY,
            MII_OFFSET_ANY, 0);
        if (LIST_FIRST(&sc->sc_mii.mii_phys) == NULL) {
                ifmedia_add(&sc->sc_mii.mii_media, IFM_ETHER|IFM_NONE, 0, NULL);
                ifmedia_set(&sc->sc_mii.mii_media, IFM_ETHER|IFM_NONE);
        } else
                ifmedia_set(&sc->sc_mii.mii_media, IFM_ETHER|IFM_AUTO);

        strlcpy(ifp->if_xname, device_xname(&sc->sc_dev), IFNAMSIZ);
        ifp->if_softc = sc;
        ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
        ifp->if_ioctl = sf_ioctl;
        ifp->if_start = sf_start;
        ifp->if_watchdog = sf_watchdog;
        ifp->if_init = sf_init;
        ifp->if_stop = sf_stop;
        IFQ_SET_READY(&ifp->if_snd);

        /*
         * Attach the interface.
         */
        if_attach(ifp);
        ether_ifattach(ifp, enaddr);

        /*
         * Make sure the interface is shutdown during reboot.
         */
        if (pmf_device_register1(&sc->sc_dev, NULL, NULL, sf_shutdown))
                pmf_class_network_register(&sc->sc_dev, ifp);
        else
                aprint_error_dev(&sc->sc_dev,
                    "couldn't establish power handler\n");
        return;

        /*
         * Free any resources we've allocated during the failed attach
         * attempt.  Do this in reverse order an fall through.
         */
 fail_5:
        for (i = 0; i < SF_NRXDESC; i++) {
                if (sc->sc_rxsoft[i].ds_dmamap != NULL)
                        bus_dmamap_destroy(sc->sc_dmat,
                            sc->sc_rxsoft[i].ds_dmamap);
        }
 fail_4:
        for (i = 0; i < SF_NTXDESC; i++) {
                if (sc->sc_txsoft[i].ds_dmamap != NULL)
                        bus_dmamap_destroy(sc->sc_dmat,
                            sc->sc_txsoft[i].ds_dmamap);
        }
        bus_dmamap_unload(sc->sc_dmat, sc->sc_cddmamap);
 fail_3:
        bus_dmamap_destroy(sc->sc_dmat, sc->sc_cddmamap);
 fail_2:
        bus_dmamem_unmap(sc->sc_dmat, (void *) sc->sc_control_data,
            sizeof(struct sf_control_data));
 fail_1:
        bus_dmamem_free(sc->sc_dmat, &seg, rseg);
 fail_0:
        return;
}

/*
 * sf_shutdown:
 *
 *      Shutdown hook -- make sure the interface is stopped at reboot.
 */
static bool
sf_shutdown(device_t self, int howto)
{
        struct sf_softc *sc;

        sc = device_private(self);
        sf_stop(&sc->sc_ethercom.ec_if, 1);

        return true;
}

/*
 * sf_start:            [ifnet interface function]
 *
 *      Start packet transmission on the interface.
 */
static void
sf_start(struct ifnet *ifp)
{
        struct sf_softc *sc = ifp->if_softc;
        struct mbuf *m0, *m;
        struct sf_txdesc0 *txd;
        struct sf_descsoft *ds;
        bus_dmamap_t dmamap;
        int error, producer, last = -1, opending, seg;

        /*
         * Remember the previous number of pending transmits.
         */
        opending = sc->sc_txpending;

        /*
         * Find out where we're sitting.
         */
        producer = SF_TXDINDEX_TO_HOST(
            TDQPI_HiPrTxProducerIndex_get(
            sf_funcreg_read(sc, SF_TxDescQueueProducerIndex)));

        /*
         * Loop through the send queue, setting up transmit descriptors
         * until we drain the queue, or use up all available transmit
         * descriptors.  Leave a blank one at the end for sanity's sake.
         */
        while (sc->sc_txpending < (SF_NTXDESC - 1)) {
                /*
                 * Grab a packet off the queue.
                 */
                IFQ_POLL(&ifp->if_snd, m0);
                if (m0 == NULL)
                        break;
                m = NULL;

                /*
                 * Get the transmit descriptor.
                 */
                txd = &sc->sc_txdescs[producer];
                ds = &sc->sc_txsoft[producer];
                dmamap = ds->ds_dmamap;

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

                /*
                 * WE ARE NOW COMMITTED TO TRANSMITTING THE PACKET.
                 */
                IFQ_DEQUEUE(&ifp->if_snd, m0);
                if (m != NULL) {
                        m_freem(m0);
                        m0 = m;
                }

                /* Initialize the descriptor. */
                txd->td_word0 =
                    htole32(TD_W0_ID | TD_W0_CRCEN | m0->m_pkthdr.len);
                if (producer == (SF_NTXDESC - 1))
                        txd->td_word0 |= TD_W0_END;
                txd->td_word1 = htole32(dmamap->dm_nsegs);
                for (seg = 0; seg < dmamap->dm_nsegs; seg++) {
                        txd->td_frags[seg].fr_addr =
                            htole32(dmamap->dm_segs[seg].ds_addr);
                        txd->td_frags[seg].fr_len =
                            htole32(dmamap->dm_segs[seg].ds_len);
                }

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

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

                /* Advance the Tx pointer. */
                sc->sc_txpending++;
                last = producer;
                producer = SF_NEXTTX(producer);

#if NBPFILTER > 0
                /*
                 * Pass the packet to any BPF listeners.
                 */
                if (ifp->if_bpf)
                        bpf_mtap(ifp->if_bpf, m0);
#endif
        }

        if (sc->sc_txpending == (SF_NTXDESC - 1)) {
                /* No more slots left; notify upper layer. */
                ifp->if_flags |= IFF_OACTIVE;
        }

        if (sc->sc_txpending != opending) {
                KASSERT(last != -1);
                /*
                 * We enqueued packets.  Cause a transmit interrupt to
                 * happen on the last packet we enqueued, and give the
                 * new descriptors to the chip by writing the new
                 * producer index.
                 */
                sc->sc_txdescs[last].td_word0 |= TD_W0_INTR;
                SF_CDTXDSYNC(sc, last, BUS_DMASYNC_PREWRITE);

                sf_funcreg_write(sc, SF_TxDescQueueProducerIndex,
                    TDQPI_HiPrTxProducerIndex(SF_TXDINDEX_TO_CHIP(producer)));

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

/*
 * sf_watchdog:         [ifnet interface function]
 *
 *      Watchdog timer handler.
 */
static void
sf_watchdog(struct ifnet *ifp)
{
        struct sf_softc *sc = ifp->if_softc;

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

        (void) sf_init(ifp);

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

/*
 * sf_ioctl:            [ifnet interface function]
 *
 *      Handle control requests from the operator.
 */
static int
sf_ioctl(struct ifnet *ifp, u_long cmd, void *data)
{
        struct sf_softc *sc = ifp->if_softc;
        int s, error;

        s = splnet();

        error = ether_ioctl(ifp, cmd, data);
        if (error == ENETRESET) {
                /*
                 * Multicast list has changed; set the hardware filter
                 * accordingly.
                 */
                if (ifp->if_flags & IFF_RUNNING)
                        sf_set_filter(sc);
                error = 0;
        }

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

        splx(s);
        return (error);
}

/*
 * sf_intr:
 *
 *      Interrupt service routine.
 */
int
sf_intr(void *arg)
{
        struct sf_softc *sc = arg;
        uint32_t isr;
        int handled = 0, wantinit = 0;

        for (;;) {
                /* Reading clears all interrupts we're interested in. */
                isr = sf_funcreg_read(sc, SF_InterruptStatus);
                if ((isr & IS_PCIPadInt) == 0)
                        break;

                handled = 1;

                /* Handle receive interrupts. */
                if (isr & IS_RxQ1DoneInt)
                        sf_rxintr(sc);

                /* Handle transmit completion interrupts. */
                if (isr & (IS_TxDmaDoneInt|IS_TxQueueDoneInt))
                        sf_txintr(sc);

                /* Handle abnormal interrupts. */
                if (isr & IS_AbnormalInterrupt) {
                        /* Statistics. */
                        if (isr & IS_StatisticWrapInt)
                                sf_stats_update(sc);

                        /* DMA errors. */
                        if (isr & IS_DmaErrInt) {
                                wantinit = 1;
                                aprint_error_dev(&sc->sc_dev, "WARNING: DMA error\n");
                        }

                        /* Transmit FIFO underruns. */
                        if (isr & IS_TxDataLowInt) {
                                if (sc->sc_txthresh < 0xff)
                                        sc->sc_txthresh++;
                                printf("%s: transmit FIFO underrun, new "
                                    "threshold: %d bytes\n",
                                    device_xname(&sc->sc_dev),
                                    sc->sc_txthresh * 16);
                                sf_funcreg_write(sc, SF_TransmitFrameCSR,
                                    sc->sc_TransmitFrameCSR |
                                    TFCSR_TransmitThreshold(sc->sc_txthresh));
                                sf_funcreg_write(sc, SF_TxDescQueueCtrl,
                                    sc->sc_TxDescQueueCtrl |
                                    TDQC_TxHighPriorityFifoThreshold(
                                                        sc->sc_txthresh));
                        }
                }
        }

        if (handled) {
                /* Reset the interface, if necessary. */
                if (wantinit)
                        sf_init(&sc->sc_ethercom.ec_if);

                /* Try and get more packets going. */
                sf_start(&sc->sc_ethercom.ec_if);
        }

        return (handled);
}

/*
 * sf_txintr:
 *
 *      Helper -- handle transmit completion interrupts.
 */
static void
sf_txintr(struct sf_softc *sc)
{
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;
        struct sf_descsoft *ds;
        uint32_t cqci, tcd;
        int consumer, producer, txidx;

 try_again:
        cqci = sf_funcreg_read(sc, SF_CompletionQueueConsumerIndex);

        consumer = CQCI_TxCompletionConsumerIndex_get(cqci);
        producer = CQPI_TxCompletionProducerIndex_get(
            sf_funcreg_read(sc, SF_CompletionQueueProducerIndex));

        if (consumer == producer)
                return;

        ifp->if_flags &= ~IFF_OACTIVE;

        while (consumer != producer) {
                SF_CDTXCSYNC(sc, consumer, BUS_DMASYNC_POSTREAD);
                tcd = le32toh(sc->sc_txcomp[consumer].tcd_word0);

                txidx = SF_TCD_INDEX_TO_HOST(TCD_INDEX(tcd));
#ifdef DIAGNOSTIC
                if ((tcd & TCD_PR) == 0)
                        aprint_error_dev(&sc->sc_dev, "Tx queue mismatch, index %d\n",
                            txidx);
#endif
                /*
                 * NOTE: stats are updated later.  We're just
                 * releasing packets that have been DMA'd to
                 * the chip.
                 */
                ds = &sc->sc_txsoft[txidx];
                SF_CDTXDSYNC(sc, txidx, BUS_DMASYNC_POSTWRITE);
                bus_dmamap_sync(sc->sc_dmat, ds->ds_dmamap,
                    0, ds->ds_dmamap->dm_mapsize,
                    BUS_DMASYNC_POSTWRITE);
                m_freem(ds->ds_mbuf);
                ds->ds_mbuf = NULL;

                consumer = SF_NEXTTCD(consumer);
                sc->sc_txpending--;
        }

        /* XXXJRT -- should be KDASSERT() */
        KASSERT(sc->sc_txpending >= 0);

        /* If all packets are done, cancel the watchdog timer. */
        if (sc->sc_txpending == 0)
                ifp->if_timer = 0;

        /* Update the consumer index. */
        sf_funcreg_write(sc, SF_CompletionQueueConsumerIndex,
            (cqci & ~CQCI_TxCompletionConsumerIndex(0x7ff)) |
             CQCI_TxCompletionConsumerIndex(consumer));

        /* Double check for new completions. */
        goto try_again;
}

/*
 * sf_rxintr:
 *
 *      Helper -- handle receive interrupts.
 */
static void
sf_rxintr(struct sf_softc *sc)
{
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;
        struct sf_descsoft *ds;
        struct sf_rcd_full *rcd;
        struct mbuf *m;
        uint32_t cqci, word0;
        int consumer, producer, bufproducer, rxidx, len;

 try_again:
        cqci = sf_funcreg_read(sc, SF_CompletionQueueConsumerIndex);

        consumer = CQCI_RxCompletionQ1ConsumerIndex_get(cqci);
        producer = CQPI_RxCompletionQ1ProducerIndex_get(
            sf_funcreg_read(sc, SF_CompletionQueueProducerIndex));
        bufproducer = RXQ1P_RxDescQ1Producer_get(
            sf_funcreg_read(sc, SF_RxDescQueue1Ptrs));

        if (consumer == producer)
                return;

        while (consumer != producer) {
                rcd = &sc->sc_rxcomp[consumer];
                SF_CDRXCSYNC(sc, consumer,
                    BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);
                SF_CDRXCSYNC(sc, consumer,
                    BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);

                word0 = le32toh(rcd->rcd_word0);
                rxidx = RCD_W0_EndIndex(word0);

                ds = &sc->sc_rxsoft[rxidx];

                consumer = SF_NEXTRCD(consumer);
                bufproducer = SF_NEXTRX(bufproducer);

                if ((word0 & RCD_W0_OK) == 0) {
                        SF_INIT_RXDESC(sc, rxidx);
                        continue;
                }

                bus_dmamap_sync(sc->sc_dmat, ds->ds_dmamap, 0,
                    ds->ds_dmamap->dm_mapsize, BUS_DMASYNC_POSTREAD);

                /*
                 * No errors; receive the packet.  Note that we have
                 * configured the Starfire to NOT transfer the CRC
                 * with the packet.
                 */
                len = RCD_W0_Length(word0);

#ifdef __NO_STRICT_ALIGNMENT
                /*
                 * Allocate a new mbuf cluster.  If that fails, we are
                 * out of memory, and must drop the packet and recycle
                 * the buffer that's already attached to this descriptor.
                 */
                m = ds->ds_mbuf;
                if (sf_add_rxbuf(sc, rxidx) != 0) {
                        ifp->if_ierrors++;
                        SF_INIT_RXDESC(sc, rxidx);
                        bus_dmamap_sync(sc->sc_dmat, ds->ds_dmamap, 0,
                            ds->ds_dmamap->dm_mapsize, BUS_DMASYNC_PREREAD);
                        continue;
                }
#else
                /*
                 * The Starfire's receive buffer must be 4-byte aligned.
                 * But this means that the data after the Ethernet header
                 * is misaligned.  We must allocate a new buffer and
                 * copy the data, shifted forward 2 bytes.
                 */
                MGETHDR(m, M_DONTWAIT, MT_DATA);
                if (m == NULL) {
 dropit:
                        ifp->if_ierrors++;
                        SF_INIT_RXDESC(sc, rxidx);
                        bus_dmamap_sync(sc->sc_dmat, ds->ds_dmamap, 0,
                            ds->ds_dmamap->dm_mapsize, BUS_DMASYNC_PREREAD);
                        continue;
                }
                if (len > (MHLEN - 2)) {
                        MCLGET(m, M_DONTWAIT);
                        if ((m->m_flags & M_EXT) == 0) {
                                m_freem(m);
                                goto dropit;
                        }
                }
                m->m_data += 2;

                /*
                 * Note that we use cluster for incoming frames, so the
                 * buffer is virtually contiguous.
                 */
                memcpy(mtod(m, void *), mtod(ds->ds_mbuf, void *), len);

                /* Allow the receive descriptor to continue using its mbuf. */
                SF_INIT_RXDESC(sc, rxidx);
                bus_dmamap_sync(sc->sc_dmat, ds->ds_dmamap, 0,
                    ds->ds_dmamap->dm_mapsize, BUS_DMASYNC_PREREAD);
#endif /* __NO_STRICT_ALIGNMENT */

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

#if NBPFILTER > 0
                /*
                 * Pass this up to any BPF listeners.
                 */
                if (ifp->if_bpf)
                        bpf_mtap(ifp->if_bpf, m);
#endif /* NBPFILTER > 0 */

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

        /* Update the chip's pointers. */
        sf_funcreg_write(sc, SF_CompletionQueueConsumerIndex,
            (cqci & ~CQCI_RxCompletionQ1ConsumerIndex(0x7ff)) |
             CQCI_RxCompletionQ1ConsumerIndex(consumer));
        sf_funcreg_write(sc, SF_RxDescQueue1Ptrs,
            RXQ1P_RxDescQ1Producer(bufproducer));

        /* Double-check for any new completions. */
        goto try_again;
}

/*
 * sf_tick:
 *
 *      One second timer, used to tick the MII and update stats.
 */
static void
sf_tick(void *arg)
{
        struct sf_softc *sc = arg;
        int s;

        s = splnet();
        mii_tick(&sc->sc_mii);
        sf_stats_update(sc);
        splx(s);

        callout_reset(&sc->sc_tick_callout, hz, sf_tick, sc);
}

/*
 * sf_stats_update:
 *
 *      Read the statitistics counters.
 */
static void
sf_stats_update(struct sf_softc *sc)
{
        struct sf_stats stats;
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;
        uint32_t *p;
        u_int i;

        p = &stats.TransmitOKFrames;
        for (i = 0; i < (sizeof(stats) / sizeof(uint32_t)); i++) {
                *p++ = sf_genreg_read(sc,
                    SF_STATS_BASE + (i * sizeof(uint32_t)));
                sf_genreg_write(sc, SF_STATS_BASE + (i * sizeof(uint32_t)), 0);
        }

        ifp->if_opackets += stats.TransmitOKFrames;

        ifp->if_collisions += stats.SingleCollisionFrames +
            stats.MultipleCollisionFrames;

        ifp->if_oerrors += stats.TransmitAbortDueToExcessiveCollisions +
            stats.TransmitAbortDueToExcessingDeferral +
            stats.FramesLostDueToInternalTransmitErrors;

        ifp->if_ipackets += stats.ReceiveOKFrames;

        ifp->if_ierrors += stats.ReceiveCRCErrors + stats.AlignmentErrors +
            stats.ReceiveFramesTooLong + stats.ReceiveFramesTooShort +
            stats.ReceiveFramesJabbersError +
            stats.FramesLostDueToInternalReceiveErrors;
}

/*
 * sf_reset:
 *
 *      Perform a soft reset on the Starfire.
 */
static void
sf_reset(struct sf_softc *sc)
{
        int i;

        sf_funcreg_write(sc, SF_GeneralEthernetCtrl, 0);

        sf_macreset(sc);

        sf_funcreg_write(sc, SF_PciDeviceConfig, PDC_SoftReset);
        for (i = 0; i < 1000; i++) {
                delay(10);
                if ((sf_funcreg_read(sc, SF_PciDeviceConfig) &
                     PDC_SoftReset) == 0)
                        break;
        }

        if (i == 1000) {
                aprint_error_dev(&sc->sc_dev, "reset failed to complete\n");
                sf_funcreg_write(sc, SF_PciDeviceConfig, 0);
        }

        delay(1000);
}

/*
 * sf_macreset:
 *
 *      Reset the MAC portion of the Starfire.
 */
static void
sf_macreset(struct sf_softc *sc)
{

        sf_genreg_write(sc, SF_MacConfig1, sc->sc_MacConfig1 | MC1_SoftRst);
        delay(1000);
        sf_genreg_write(sc, SF_MacConfig1, sc->sc_MacConfig1);
}

/*
 * sf_init:             [ifnet interface function]
 *
 *      Initialize the interface.  Must be called at splnet().
 */
static int
sf_init(struct ifnet *ifp)
{
        struct sf_softc *sc = ifp->if_softc;
        struct sf_descsoft *ds;
        int error = 0;
        u_int i;

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

        /*
         * Reset the Starfire to a known state.
         */
        sf_reset(sc);

        /* Clear the stat counters. */
        for (i = 0; i < sizeof(struct sf_stats); i += sizeof(uint32_t))
                sf_genreg_write(sc, SF_STATS_BASE + i, 0);

        /*
         * Initialize the transmit descriptor ring.
         */
        memset(sc->sc_txdescs, 0, sizeof(sc->sc_txdescs));
        sf_funcreg_write(sc, SF_TxDescQueueHighAddr, 0);
        sf_funcreg_write(sc, SF_HiPrTxDescQueueBaseAddr, SF_CDTXDADDR(sc, 0));
        sf_funcreg_write(sc, SF_LoPrTxDescQueueBaseAddr, 0);

        /*
         * Initialize the transmit completion ring.
         */
        for (i = 0; i < SF_NTCD; i++) {
                sc->sc_txcomp[i].tcd_word0 = TCD_DMA_ID;
                SF_CDTXCSYNC(sc, i, BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);
        }
        sf_funcreg_write(sc, SF_CompletionQueueHighAddr, 0);
        sf_funcreg_write(sc, SF_TxCompletionQueueCtrl, SF_CDTXCADDR(sc, 0));

        /*
         * Initialize the receive descriptor ring.
         */
        for (i = 0; i < SF_NRXDESC; i++) {
                ds = &sc->sc_rxsoft[i];
                if (ds->ds_mbuf == NULL) {
                        if ((error = sf_add_rxbuf(sc, i)) != 0) {
                                aprint_error_dev(&sc->sc_dev, "unable to allocate or map rx "
                                    "buffer %d, error = %d\n",
                                    i, error);
                                /*
                                 * XXX Should attempt to run with fewer receive
                                 * XXX buffers instead of just failing.
                                 */
                                sf_rxdrain(sc);
                                goto out;
                        }
                } else
                        SF_INIT_RXDESC(sc, i);
        }
        sf_funcreg_write(sc, SF_RxDescQueueHighAddress, 0);
        sf_funcreg_write(sc, SF_RxDescQueue1LowAddress, SF_CDRXDADDR(sc, 0));
        sf_funcreg_write(sc, SF_RxDescQueue2LowAddress, 0);

        /*
         * Initialize the receive completion ring.
         */
        for (i = 0; i < SF_NRCD; i++) {
                sc->sc_rxcomp[i].rcd_word0 = RCD_W0_ID;
                sc->sc_rxcomp[i].rcd_word1 = 0;
                sc->sc_rxcomp[i].rcd_word2 = 0;
                sc->sc_rxcomp[i].rcd_timestamp = 0;
                SF_CDRXCSYNC(sc, i, BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);
        }
        sf_funcreg_write(sc, SF_RxCompletionQueue1Ctrl, SF_CDRXCADDR(sc, 0) |
            RCQ1C_RxCompletionQ1Type(3));
        sf_funcreg_write(sc, SF_RxCompletionQueue2Ctrl, 0);

        /*
         * Initialize the Tx CSR.
         */
        sc->sc_TransmitFrameCSR = 0;
        sf_funcreg_write(sc, SF_TransmitFrameCSR,
            sc->sc_TransmitFrameCSR |
            TFCSR_TransmitThreshold(sc->sc_txthresh));

        /*
         * Initialize the Tx descriptor control register.
         */
        sc->sc_TxDescQueueCtrl = TDQC_SkipLength(0) |
            TDQC_TxDmaBurstSize(4) |    /* default */
            TDQC_MinFrameSpacing(3) |   /* 128 bytes */
            TDQC_TxDescType(0);
        sf_funcreg_write(sc, SF_TxDescQueueCtrl,
            sc->sc_TxDescQueueCtrl |
            TDQC_TxHighPriorityFifoThreshold(sc->sc_txthresh));

        /*
         * Initialize the Rx descriptor control registers.
         */
        sf_funcreg_write(sc, SF_RxDescQueue1Ctrl,
            RDQ1C_RxQ1BufferLength(MCLBYTES) |
            RDQ1C_RxDescSpacing(0));
        sf_funcreg_write(sc, SF_RxDescQueue2Ctrl, 0);

        /*
         * Initialize the Tx descriptor producer indices.
         */
        sf_funcreg_write(sc, SF_TxDescQueueProducerIndex,
            TDQPI_HiPrTxProducerIndex(0) |
            TDQPI_LoPrTxProducerIndex(0));

        /*
         * Initialize the Rx descriptor producer indices.
         */
        sf_funcreg_write(sc, SF_RxDescQueue1Ptrs,
            RXQ1P_RxDescQ1Producer(SF_NRXDESC - 1));
        sf_funcreg_write(sc, SF_RxDescQueue2Ptrs,
            RXQ2P_RxDescQ2Producer(0));

        /*
         * Initialize the Tx and Rx completion queue consumer indices.
         */
        sf_funcreg_write(sc, SF_CompletionQueueConsumerIndex,
            CQCI_TxCompletionConsumerIndex(0) |
            CQCI_RxCompletionQ1ConsumerIndex(0));
        sf_funcreg_write(sc, SF_RxHiPrCompletionPtrs, 0);

        /*
         * Initialize the Rx DMA control register.
         */
        sf_funcreg_write(sc, SF_RxDmaCtrl,
            RDC_RxHighPriorityThreshold(6) |    /* default */
            RDC_RxBurstSize(4));                /* default */

        /*
         * Set the receive filter.
         */
        sc->sc_RxAddressFilteringCtl = 0;
        sf_set_filter(sc);

        /*
         * Set MacConfig1.  When we set the media, MacConfig1 will
         * actually be written and the MAC part reset.
         */
        sc->sc_MacConfig1 = MC1_PadEn;

        /*
         * Set the media.
         */
        if ((error = ether_mediachange(ifp)) != 0)
                goto out;

        /*
         * Initialize the interrupt register.
         */
        sc->sc_InterruptEn = IS_PCIPadInt | IS_RxQ1DoneInt |
            IS_TxQueueDoneInt | IS_TxDmaDoneInt | IS_DmaErrInt |
            IS_StatisticWrapInt;
        sf_funcreg_write(sc, SF_InterruptEn, sc->sc_InterruptEn);

        sf_funcreg_write(sc, SF_PciDeviceConfig, PDC_IntEnable |
            PDC_PCIMstDmaEn | (1 << PDC_FifoThreshold_SHIFT));

        /*
         * Start the transmit and receive processes.
         */
        sf_funcreg_write(sc, SF_GeneralEthernetCtrl,
            GEC_TxDmaEn|GEC_RxDmaEn|GEC_TransmitEn|GEC_ReceiveEn);

        /* Start the on second clock. */
        callout_reset(&sc->sc_tick_callout, hz, sf_tick, sc);

        /*
         * Note that the interface is now running.
         */
        ifp->if_flags |= IFF_RUNNING;
        ifp->if_flags &= ~IFF_OACTIVE;

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

/*
 * sf_rxdrain:
 *
 *      Drain the receive queue.
 */
static void
sf_rxdrain(struct sf_softc *sc)
{
        struct sf_descsoft *ds;
        int i;

        for (i = 0; i < SF_NRXDESC; i++) {
                ds = &sc->sc_rxsoft[i];
                if (ds->ds_mbuf != NULL) {
                        bus_dmamap_unload(sc->sc_dmat, ds->ds_dmamap);
                        m_freem(ds->ds_mbuf);
                        ds->ds_mbuf = NULL;
                }
        }
}

/*
 * sf_stop:             [ifnet interface function]
 *
 *      Stop transmission on the interface.
 */
static void
sf_stop(struct ifnet *ifp, int disable)
{
        struct sf_softc *sc = ifp->if_softc;
        struct sf_descsoft *ds;
        int i;

        /* Stop the one second clock. */
        callout_stop(&sc->sc_tick_callout);

        /* Down the MII. */
        mii_down(&sc->sc_mii);

        /* Disable interrupts. */
        sf_funcreg_write(sc, SF_InterruptEn, 0);

        /* Stop the transmit and receive processes. */
        sf_funcreg_write(sc, SF_GeneralEthernetCtrl, 0);

        /*
         * Release any queued transmit buffers.
         */
        for (i = 0; i < SF_NTXDESC; i++) {
                ds = &sc->sc_txsoft[i];
                if (ds->ds_mbuf != NULL) {
                        bus_dmamap_unload(sc->sc_dmat, ds->ds_dmamap);
                        m_freem(ds->ds_mbuf);
                        ds->ds_mbuf = NULL;
                }
        }

        /*
         * Mark the interface down and cancel the watchdog timer.
         */
        ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
        ifp->if_timer = 0;

        if (disable)
                sf_rxdrain(sc);
}

/*
 * sf_read_eeprom:
 *
 *      Read from the Starfire EEPROM.
 */
static uint8_t
sf_read_eeprom(struct sf_softc *sc, int offset)
{
        uint32_t reg;

        reg = sf_genreg_read(sc, SF_EEPROM_BASE + (offset & ~3));

        return ((reg >> (8 * (offset & 3))) & 0xff);
}

/*
 * sf_add_rxbuf:
 *
 *      Add a receive buffer to the indicated descriptor.
 */
static int
sf_add_rxbuf(struct sf_softc *sc, int idx)
{
        struct sf_descsoft *ds = &sc->sc_rxsoft[idx];
        struct mbuf *m;
        int error;

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

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

        if (ds->ds_mbuf != NULL)
                bus_dmamap_unload(sc->sc_dmat, ds->ds_dmamap);

        ds->ds_mbuf = m;

        error = bus_dmamap_load(sc->sc_dmat, ds->ds_dmamap,
            m->m_ext.ext_buf, m->m_ext.ext_size, NULL,
            BUS_DMA_READ|BUS_DMA_NOWAIT);
        if (error) {
                aprint_error_dev(&sc->sc_dev, "can't load rx DMA map %d, error = %d\n",
                    idx, error);
                panic("sf_add_rxbuf"); /* XXX */
        }

        bus_dmamap_sync(sc->sc_dmat, ds->ds_dmamap, 0,
            ds->ds_dmamap->dm_mapsize, BUS_DMASYNC_PREREAD);

        SF_INIT_RXDESC(sc, idx);

        return (0);
}

static void
sf_set_filter_perfect(struct sf_softc *sc, int slot, const uint8_t *enaddr)
{
        uint32_t reg0, reg1, reg2;

        reg0 = enaddr[5] | (enaddr[4] << 8);
        reg1 = enaddr[3] | (enaddr[2] << 8);
        reg2 = enaddr[1] | (enaddr[0] << 8);

        sf_genreg_write(sc, SF_PERFECT_BASE + (slot * 0x10) + 0, reg0);
        sf_genreg_write(sc, SF_PERFECT_BASE + (slot * 0x10) + 4, reg1);
        sf_genreg_write(sc, SF_PERFECT_BASE + (slot * 0x10) + 8, reg2);
}

static void
sf_set_filter_hash(struct sf_softc *sc, uint8_t *enaddr)
{
        uint32_t hash, slot, reg;

        hash = ether_crc32_be(enaddr, ETHER_ADDR_LEN) >> 23;
        slot = hash >> 4;

        reg = sf_genreg_read(sc, SF_HASH_BASE + (slot * 0x10));
        reg |= 1 << (hash & 0xf);
        sf_genreg_write(sc, SF_HASH_BASE + (slot * 0x10), reg);
}

/*
 * sf_set_filter:
 *
 *      Set the Starfire receive filter.
 */
static void
sf_set_filter(struct sf_softc *sc)
{
        struct ethercom *ec = &sc->sc_ethercom;
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;
        struct ether_multi *enm;
        struct ether_multistep step;
        int i;

        /* Start by clearing the perfect and hash tables. */
        for (i = 0; i < SF_PERFECT_SIZE; i += sizeof(uint32_t))
                sf_genreg_write(sc, SF_PERFECT_BASE + i, 0);

        for (i = 0; i < SF_HASH_SIZE; i += sizeof(uint32_t))
                sf_genreg_write(sc, SF_HASH_BASE + i, 0);

        /*
         * Clear the perfect and hash mode bits.
         */
        sc->sc_RxAddressFilteringCtl &=
            ~(RAFC_PerfectFilteringMode(3) | RAFC_HashFilteringMode(3));

        if (ifp->if_flags & IFF_BROADCAST)
                sc->sc_RxAddressFilteringCtl |= RAFC_PassBroadcast;
        else
                sc->sc_RxAddressFilteringCtl &= ~RAFC_PassBroadcast;

        if (ifp->if_flags & IFF_PROMISC) {
                sc->sc_RxAddressFilteringCtl |= RAFC_PromiscuousMode;
                goto allmulti;
        } else
                sc->sc_RxAddressFilteringCtl &= ~RAFC_PromiscuousMode;

        /*
         * Set normal perfect filtering mode.
         */
        sc->sc_RxAddressFilteringCtl |= RAFC_PerfectFilteringMode(1);

        /*
         * First, write the station address to the perfect filter
         * table.
         */
        sf_set_filter_perfect(sc, 0, CLLADDR(ifp->if_sadl));

        /*
         * Now set the hash bits for each multicast address in our
         * list.
         */
        ETHER_FIRST_MULTI(step, ec, enm);
        if (enm == NULL)
                goto done;
        while (enm != NULL) {
                if (memcmp(enm->enm_addrlo, enm->enm_addrhi, ETHER_ADDR_LEN)) {
                        /*
                         * We must listen to a range of multicast addresses.
                         * For now, just accept all multicasts, rather than
                         * trying to set only those filter bits needed to match
                         * the range.  (At this time, the only use of address
                         * ranges is for IP multicast routing, for which the
                         * range is big enough to require all bits set.)
                         */
                        goto allmulti;
                }
                sf_set_filter_hash(sc, enm->enm_addrlo);
                ETHER_NEXT_MULTI(step, enm);
        }

        /*
         * Set "hash only multicast dest, match regardless of VLAN ID".
         */
        sc->sc_RxAddressFilteringCtl |= RAFC_HashFilteringMode(2);
        goto done;

 allmulti:
        /*
         * XXX RAFC_PassMulticast is sub-optimal if using VLAN mode.
         */
        sc->sc_RxAddressFilteringCtl |= RAFC_PassMulticast;
        ifp->if_flags |= IFF_ALLMULTI;

 done:
        sf_funcreg_write(sc, SF_RxAddressFilteringCtl,
            sc->sc_RxAddressFilteringCtl);
}

/*
 * sf_mii_read:         [mii interface function]
 *
 *      Read from the MII.
 */
static int
sf_mii_read(device_t self, int phy, int reg)
{
        struct sf_softc *sc = (void *) self;
        uint32_t v;
        int i;

        for (i = 0; i < 1000; i++) {
                v = sf_genreg_read(sc, SF_MII_PHY_REG(phy, reg));
                if (v & MiiDataValid)
                        break;
                delay(1);
        }

        if ((v & MiiDataValid) == 0)
                return (0);

        if (MiiRegDataPort(v) == 0xffff)
                return (0);

        return (MiiRegDataPort(v));
}

/*
 * sf_mii_write:        [mii interface function]
 *
 *      Write to the MII.
 */
static void
sf_mii_write(device_t self, int phy, int reg, int val)
{
        struct sf_softc *sc = (void *) self;
        int i;

        sf_genreg_write(sc, SF_MII_PHY_REG(phy, reg), val);

        for (i = 0; i < 1000; i++) {
                if ((sf_genreg_read(sc, SF_MII_PHY_REG(phy, reg)) &
                     MiiBusy) == 0)
                        return;
                delay(1);
        }

        printf("%s: MII write timed out\n", device_xname(&sc->sc_dev));
}

/*
 * sf_mii_statchg:      [mii interface function]
 *
 *      Callback from the PHY when the media changes.
 */
static void
sf_mii_statchg(device_t self)
{
        struct sf_softc *sc = (void *) self;
        uint32_t ipg;

        if (sc->sc_mii.mii_media_active & IFM_FDX) {
                sc->sc_MacConfig1 |= MC1_FullDuplex;
                ipg = 0x15;
        } else {
                sc->sc_MacConfig1 &= ~MC1_FullDuplex;
                ipg = 0x11;
        }

        sf_genreg_write(sc, SF_MacConfig1, sc->sc_MacConfig1);
        sf_macreset(sc);

        sf_genreg_write(sc, SF_BkToBkIPG, ipg);
}