/*      $NetBSD: lance.c,v 1.34 2005/12/24 20:27:30 perry Exp $ */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Charles M. Hannum and by Jason R. Thorpe of the Numerical Aerospace
 * Simulation Facility, NASA Ames Research Center.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*-
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ralph Campbell and Rick Macklem.
 *
 * 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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/endian.h>
#include <sys/lock.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/socket.h>
#include <sys/sockio.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 <machine/bus.h>

#include <dev/le/lancereg.h>
#include <dev/le/lancevar.h>

static void lance_start(if_t);
static void lance_stop(struct lance_softc *);
static void lance_init(void *);
static void lance_watchdog(void *s);
static int lance_mediachange(if_t);
static void lance_mediastatus(if_t, struct ifmediareq *);
static int lance_ioctl(if_t, u_long, caddr_t);

int
lance_config(struct lance_softc *sc, const char* name, int unit)
{
        if_t ifp;
        int i, nbuf;

        if (LE_LOCK_INITIALIZED(sc) == 0)
                return (ENXIO);

        ifp = sc->sc_ifp = if_alloc(IFT_ETHER);
        if (ifp == NULL)
                return (ENOSPC);

        callout_init_mtx(&sc->sc_wdog_ch, &sc->sc_mtx, 0);

        /* Initialize ifnet structure. */
        if_setsoftc(ifp, sc);
        if_initname(ifp, name, unit);
        if_setstartfn(ifp, lance_start);
        if_setioctlfn(ifp, lance_ioctl);
        if_setinitfn(ifp, lance_init);
        if_setflags(ifp, IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
#ifdef LANCE_REVC_BUG
        if_setflagsbit(ifp, 0, IFF_MULTICAST);
#endif
        if_setbaudrate(ifp, IF_Mbps(10));
        if_setsendqlen(ifp, ifqmaxlen);
        if_setsendqready(ifp);

        /* Initialize ifmedia structures. */
        ifmedia_init(&sc->sc_media, 0, lance_mediachange, lance_mediastatus);
        if (sc->sc_supmedia != NULL) {
                for (i = 0; i < sc->sc_nsupmedia; i++)
                        ifmedia_add(&sc->sc_media, sc->sc_supmedia[i], 0, NULL);
                ifmedia_set(&sc->sc_media, sc->sc_defaultmedia);
        } else {
                ifmedia_add(&sc->sc_media,
                    IFM_MAKEWORD(IFM_ETHER, IFM_MANUAL, 0, 0), 0, NULL);
                ifmedia_set(&sc->sc_media,
                    IFM_MAKEWORD(IFM_ETHER, IFM_MANUAL, 0, 0));
        }

        switch (sc->sc_memsize) {
        case 8192:
                sc->sc_nrbuf = 4;
                sc->sc_ntbuf = 1;
                break;
        case 16384:
                sc->sc_nrbuf = 8;
                sc->sc_ntbuf = 2;
                break;
        case 32768:
                sc->sc_nrbuf = 16;
                sc->sc_ntbuf = 4;
                break;
        case 65536:
                sc->sc_nrbuf = 32;
                sc->sc_ntbuf = 8;
                break;
        case 131072:
                sc->sc_nrbuf = 64;
                sc->sc_ntbuf = 16;
                break;
        case 262144:
                sc->sc_nrbuf = 128;
                sc->sc_ntbuf = 32;
                break;
        default:
                /* weird memory size; cope with it */
                nbuf = sc->sc_memsize / LEBLEN;
                sc->sc_ntbuf = nbuf / 5;
                sc->sc_nrbuf = nbuf - sc->sc_ntbuf;
        }

        if_printf(ifp, "%d receive buffers, %d transmit buffers\n",
            sc->sc_nrbuf, sc->sc_ntbuf);

        /* Make sure the chip is stopped. */
        LE_LOCK(sc);
        lance_stop(sc);
        LE_UNLOCK(sc);

        return (0);
}

void
lance_attach(struct lance_softc *sc)
{
        if_t ifp = sc->sc_ifp;

        /* Attach the interface. */
        ether_ifattach(ifp, sc->sc_enaddr);

        /* Claim 802.1q capability. */
        if_setifheaderlen(ifp, sizeof(struct ether_vlan_header));
        if_setcapabilitiesbit(ifp, IFCAP_VLAN_MTU, 0);
        if_setcapenablebit(ifp, IFCAP_VLAN_MTU, 0);
}

void
lance_detach(struct lance_softc *sc)
{
        if_t ifp = sc->sc_ifp;

        LE_LOCK(sc);
        lance_stop(sc);
        LE_UNLOCK(sc);
        callout_drain(&sc->sc_wdog_ch);
        ether_ifdetach(ifp);
        if_free(ifp);
}

void
lance_suspend(struct lance_softc *sc)
{

        LE_LOCK(sc);
        lance_stop(sc);
        LE_UNLOCK(sc);
}

void
lance_resume(struct lance_softc *sc)
{

        LE_LOCK(sc);
        if (if_getflags(sc->sc_ifp) & IFF_UP)
                lance_init_locked(sc);
        LE_UNLOCK(sc);
}

static void
lance_start(if_t ifp)
{
        struct lance_softc *sc = if_getsoftc(ifp);

        LE_LOCK(sc);
        (*sc->sc_start_locked)(sc);
        LE_UNLOCK(sc);
}

static void
lance_stop(struct lance_softc *sc)
{
        if_t ifp = sc->sc_ifp;

        LE_LOCK_ASSERT(sc, MA_OWNED);

        /*
         * Mark the interface down and cancel the watchdog timer.
         */
        if_setdrvflagbits(ifp, 0, (IFF_DRV_RUNNING | IFF_DRV_OACTIVE));
        callout_stop(&sc->sc_wdog_ch);
        sc->sc_wdog_timer = 0;

        (*sc->sc_wrcsr)(sc, LE_CSR0, LE_C0_STOP);
}

static void
lance_init(void *xsc)
{
        struct lance_softc *sc = (struct lance_softc *)xsc;

        LE_LOCK(sc);
        lance_init_locked(sc);
        LE_UNLOCK(sc);
}

/*
 * Initialization of interface; set up initialization block
 * and transmit/receive descriptor rings.
 */
void
lance_init_locked(struct lance_softc *sc)
{
        if_t ifp = sc->sc_ifp;
        u_long a;
        int timo;

        LE_LOCK_ASSERT(sc, MA_OWNED);

        (*sc->sc_wrcsr)(sc, LE_CSR0, LE_C0_STOP);
        DELAY(100);

        /* Newer LANCE chips have a reset register. */
        if (sc->sc_hwreset)
                (*sc->sc_hwreset)(sc);

        /* Set the correct byte swapping mode, etc. */
        (*sc->sc_wrcsr)(sc, LE_CSR3, sc->sc_conf3);

        /* Set the current media. This may require the chip to be stopped. */
        if (sc->sc_mediachange)
                (void)(*sc->sc_mediachange)(sc);

        /*
         * Update our private copy of the Ethernet address.
         * We NEED the copy so we can ensure its alignment!
         */
        memcpy(sc->sc_enaddr, if_getlladdr(ifp), ETHER_ADDR_LEN);

        /* Set up LANCE init block. */
        (*sc->sc_meminit)(sc);

        /* Give LANCE the physical address of its init block. */
        a = sc->sc_addr + LE_INITADDR(sc);
        (*sc->sc_wrcsr)(sc, LE_CSR1, a & 0xffff);
        (*sc->sc_wrcsr)(sc, LE_CSR2, a >> 16);

        /* Try to initialize the LANCE. */
        DELAY(100);
        (*sc->sc_wrcsr)(sc, LE_CSR0, LE_C0_INIT);

        /* Wait for initialization to finish. */
        for (timo = 100000; timo; timo--)
                if ((*sc->sc_rdcsr)(sc, LE_CSR0) & LE_C0_IDON)
                        break;

        if ((*sc->sc_rdcsr)(sc, LE_CSR0) & LE_C0_IDON) {
                /* Start the LANCE. */
                (*sc->sc_wrcsr)(sc, LE_CSR0, LE_C0_INEA | LE_C0_STRT);
                if_setdrvflagbits(ifp, IFF_DRV_RUNNING, 0);
                if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);
                sc->sc_wdog_timer = 0;
                callout_reset(&sc->sc_wdog_ch, hz, lance_watchdog, sc);
                (*sc->sc_start_locked)(sc);
        } else
                if_printf(ifp, "controller failed to initialize\n");

        if (sc->sc_hwinit)
                (*sc->sc_hwinit)(sc);
}

/*
 * Routine to copy from mbuf chain to transmit buffer in
 * network buffer memory.
 */
int
lance_put(struct lance_softc *sc, int boff, struct mbuf *m)
{
        struct mbuf *n;
        int len, tlen = 0;

        LE_LOCK_ASSERT(sc, MA_OWNED);

        for (; m; m = n) {
                len = m->m_len;
                if (len == 0) {
                        n = m_free(m);
                        m = NULL;
                        continue;
                }
                (*sc->sc_copytobuf)(sc, mtod(m, caddr_t), boff, len);
                boff += len;
                tlen += len;
                n = m_free(m);
                m = NULL;
        }
        if (tlen < LEMINSIZE) {
                (*sc->sc_zerobuf)(sc, boff, LEMINSIZE - tlen);
                tlen = LEMINSIZE;
        }
        return (tlen);
}

/*
 * Pull data off an interface.
 * Len is length of data, with local net header stripped.
 * We copy the data into mbufs.  When full cluster sized units are present
 * we copy into clusters.
 */
struct mbuf *
lance_get(struct lance_softc *sc, int boff, int totlen)
{
        if_t ifp = sc->sc_ifp;
        struct mbuf *m, *m0, *newm;
        caddr_t newdata;
        int len;

        if (totlen <= ETHER_HDR_LEN || totlen > LEBLEN - ETHER_CRC_LEN) {
#ifdef LEDEBUG
                if_printf(ifp, "invalid packet size %d; dropping\n", totlen);
#endif
                return (NULL);
        }

        MGETHDR(m0, M_NOWAIT, MT_DATA);
        if (m0 == NULL)
                return (NULL);
        m0->m_pkthdr.rcvif = ifp;
        m0->m_pkthdr.len = totlen;
        len = MHLEN;
        m = m0;

        while (totlen > 0) {
                if (totlen >= MINCLSIZE) {
                        if (!(MCLGET(m, M_NOWAIT)))
                                goto bad;
                        len = MCLBYTES;
                }

                if (m == m0) {
                        newdata = (caddr_t)
                            ALIGN(m->m_data + ETHER_HDR_LEN) - ETHER_HDR_LEN;
                        len -= newdata - m->m_data;
                        m->m_data = newdata;
                }

                m->m_len = len = min(totlen, len);
                (*sc->sc_copyfrombuf)(sc, mtod(m, caddr_t), boff, len);
                boff += len;

                totlen -= len;
                if (totlen > 0) {
                        MGET(newm, M_NOWAIT, MT_DATA);
                        if (newm == NULL)
                                goto bad;
                        len = MLEN;
                        m = m->m_next = newm;
                }
        }

        return (m0);

 bad:
        m_freem(m0);
        return (NULL);
}

static void
lance_watchdog(void *xsc)
{
        struct lance_softc *sc = (struct lance_softc *)xsc;
        if_t ifp = sc->sc_ifp;

        LE_LOCK_ASSERT(sc, MA_OWNED);

        if (sc->sc_wdog_timer == 0 || --sc->sc_wdog_timer != 0) {
                callout_reset(&sc->sc_wdog_ch, hz, lance_watchdog, sc);
                return;
        }

        if_printf(ifp, "device timeout\n");
        if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
        lance_init_locked(sc);
}

static int
lance_mediachange(if_t ifp)
{
        struct lance_softc *sc = if_getsoftc(ifp);

        if (sc->sc_mediachange) {
                /*
                 * For setting the port in LE_CSR15 the PCnet chips must
                 * be powered down or stopped and unlike documented may
                 * not take effect without an initialization. So don't
                 * invoke (*sc_mediachange) directly here but go through
                 * lance_init_locked().
                 */
                LE_LOCK(sc);
                lance_stop(sc);
                lance_init_locked(sc);
                if (!if_sendq_empty(ifp))
                        (*sc->sc_start_locked)(sc);
                LE_UNLOCK(sc);
        }
        return (0);
}

static void
lance_mediastatus(if_t ifp, struct ifmediareq *ifmr)
{
        struct lance_softc *sc = if_getsoftc(ifp);

        LE_LOCK(sc);
        if (!(if_getflags(ifp) & IFF_UP)) {
                LE_UNLOCK(sc);
                return;
        }

        ifmr->ifm_status = IFM_AVALID;
        if (sc->sc_flags & LE_CARRIER)
                ifmr->ifm_status |= IFM_ACTIVE;

        if (sc->sc_mediastatus)
                (*sc->sc_mediastatus)(sc, ifmr);
        LE_UNLOCK(sc);
}

/*
 * Process an ioctl request.
 */
static int
lance_ioctl(if_t ifp, u_long cmd, caddr_t data)
{
        struct lance_softc *sc = if_getsoftc(ifp);
        struct ifreq *ifr = (struct ifreq *)data;
        int error = 0;

        switch (cmd) {
        case SIOCSIFFLAGS:
                LE_LOCK(sc);
                if (if_getflags(ifp) & IFF_PROMISC) {
                        if (!(sc->sc_flags & LE_PROMISC)) {
                                sc->sc_flags |= LE_PROMISC;
                                lance_init_locked(sc);
                        }
                } else if (sc->sc_flags & LE_PROMISC) {
                        sc->sc_flags &= ~LE_PROMISC;
                        lance_init_locked(sc);
                }

                if ((if_getflags(ifp) & IFF_ALLMULTI) &&
                    !(sc->sc_flags & LE_ALLMULTI)) {
                        sc->sc_flags |= LE_ALLMULTI;
                        lance_init_locked(sc);
                } else if (!(if_getflags(ifp) & IFF_ALLMULTI) &&
                    (sc->sc_flags & LE_ALLMULTI)) {
                        sc->sc_flags &= ~LE_ALLMULTI;
                        lance_init_locked(sc);
                }

                if (!(if_getflags(ifp) & IFF_UP) &&
                    if_getdrvflags(ifp) & IFF_DRV_RUNNING) {
                        /*
                         * If interface is marked down and it is running, then
                         * stop it.
                         */
                        lance_stop(sc);
                } else if (if_getflags(ifp) & IFF_UP &&
                    !(if_getdrvflags(ifp) & IFF_DRV_RUNNING)) {
                        /*
                         * If interface is marked up and it is stopped, then
                         * start it.
                         */
                        lance_init_locked(sc);
                }
#ifdef LEDEBUG
                if (if_getflags(ifp) & IFF_DEBUG)
                        sc->sc_flags |= LE_DEBUG;
                else
                        sc->sc_flags &= ~LE_DEBUG;
#endif
                LE_UNLOCK(sc);
                break;

        case SIOCADDMULTI:
        case SIOCDELMULTI:
                /*
                 * Multicast list has changed; set the hardware filter
                 * accordingly.
                 */
                LE_LOCK(sc);
                if (if_getdrvflags(ifp) & IFF_DRV_RUNNING)
                        lance_init_locked(sc);
                LE_UNLOCK(sc);
                break;

        case SIOCGIFMEDIA:
        case SIOCSIFMEDIA:
                error = ifmedia_ioctl(ifp, ifr, &sc->sc_media, cmd);
                break;

        default:
                error = ether_ioctl(ifp, cmd, data);
                break;
        }

        return (error);
}

struct lance_hash_maddr_ctx {
        struct lance_softc *sc;
        uint16_t *af;
};

static u_int
lance_hash_maddr(void *arg, struct sockaddr_dl *sdl, u_int cnt)
{
        struct lance_hash_maddr_ctx *ctx = arg;
        struct lance_softc *sc = ctx->sc;
        uint32_t crc;

        crc = ether_crc32_le(LLADDR(sdl), ETHER_ADDR_LEN);
        /* Just want the 6 most significant bits. */
        crc >>= 26;
        /* Set the corresponding bit in the filter. */
        ctx->af[crc >> 4] |= LE_HTOLE16(1 << (crc & 0xf));

        return (1);
}

/*
 * Set up the logical address filter.
 */
void
lance_setladrf(struct lance_softc *sc, uint16_t *af)
{
        if_t ifp = sc->sc_ifp;
        struct lance_hash_maddr_ctx ctx = { sc, af };

        /*
         * Set up multicast address filter by passing all multicast addresses
         * through a crc generator, and then using the high order 6 bits as an
         * index into the 64 bit logical address filter.  The high order bit
         * selects the word, while the rest of the bits select the bit within
         * the word.
         */

        if (if_getflags(ifp) & IFF_PROMISC || sc->sc_flags & LE_ALLMULTI) {
                af[0] = af[1] = af[2] = af[3] = 0xffff;
                return;
        }

        af[0] = af[1] = af[2] = af[3] = 0x0000;
        if_foreach_llmaddr(ifp, lance_hash_maddr, &ctx);
}

/*
 * Routines for accessing the transmit and receive buffers.
 * The various CPU and adapter configurations supported by this
 * driver require three different access methods for buffers
 * and descriptors:
 *      (1) contig (contiguous data; no padding),
 *      (2) gap2 (two bytes of data followed by two bytes of padding),
 *      (3) gap16 (16 bytes of data followed by 16 bytes of padding).
 */

/*
 * contig: contiguous data with no padding.
 *
 * Buffers may have any alignment.
 */

void
lance_copytobuf_contig(struct lance_softc *sc, void *from, int boff, int len)
{
        volatile caddr_t buf = sc->sc_mem;

        /*
         * Just call memcpy() to do the work.
         */
        memcpy(buf + boff, from, len);
}

void
lance_copyfrombuf_contig(struct lance_softc *sc, void *to, int boff, int len)
{
        volatile caddr_t buf = sc->sc_mem;

        /*
         * Just call memcpy() to do the work.
         */
        memcpy(to, buf + boff, len);
}

void
lance_zerobuf_contig(struct lance_softc *sc, int boff, int len)
{
        volatile caddr_t buf = sc->sc_mem;

        /*
         * Just let memset() do the work
         */
        memset(buf + boff, 0, len);
}

#if 0
/*
 * Examples only; duplicate these and tweak (if necessary) in
 * machine-specific front-ends.
 */

/*
 * gap2: two bytes of data followed by two bytes of pad.
 *
 * Buffers must be 4-byte aligned.  The code doesn't worry about
 * doing an extra byte.
 */

static void
lance_copytobuf_gap2(struct lance_softc *sc, void *fromv, int boff, int len)
{
        volatile caddr_t buf = sc->sc_mem;
        caddr_t from = fromv;
        volatile uint16_t *bptr;

        if (boff & 0x1) {
                /* Handle unaligned first byte. */
                bptr = ((volatile uint16_t *)buf) + (boff - 1);
                *bptr = (*from++ << 8) | (*bptr & 0xff);
                bptr += 2;
                len--;
        } else
                bptr = ((volatile uint16_t *)buf) + boff;
        while (len > 1) {
                *bptr = (from[1] << 8) | (from[0] & 0xff);
                bptr += 2;
                from += 2;
                len -= 2;
        }
        if (len == 1)
                *bptr = (uint16_t)*from;
}

static void
lance_copyfrombuf_gap2(struct lance_softc *sc, void *tov, int boff, int len)
{
        volatile caddr_t buf = sc->sc_mem;
        caddr_t to = tov;
        volatile uint16_t *bptr;
        uint16_t tmp;

        if (boff & 0x1) {
                /* Handle unaligned first byte. */
                bptr = ((volatile uint16_t *)buf) + (boff - 1);
                *to++ = (*bptr >> 8) & 0xff;
                bptr += 2;
                len--;
        } else
                bptr = ((volatile uint16_t *)buf) + boff;
        while (len > 1) {
                tmp = *bptr;
                *to++ = tmp & 0xff;
                *to++ = (tmp >> 8) & 0xff;
                bptr += 2;
                len -= 2;
        }
        if (len == 1)
                *to = *bptr & 0xff;
}

static void
lance_zerobuf_gap2(struct lance_softc *sc, int boff, int len)
{
        volatile caddr_t buf = sc->sc_mem;
        volatile uint16_t *bptr;

        if ((unsigned)boff & 0x1) {
                bptr = ((volatile uint16_t *)buf) + (boff - 1);
                *bptr &= 0xff;
                bptr += 2;
                len--;
        } else
                bptr = ((volatile uint16_t *)buf) + boff;
        while (len > 0) {
                *bptr = 0;
                bptr += 2;
                len -= 2;
        }
}

/*
 * gap16: 16 bytes of data followed by 16 bytes of pad.
 *
 * Buffers must be 32-byte aligned.
 */

static void
lance_copytobuf_gap16(struct lance_softc *sc, void *fromv, int boff, int len)
{
        volatile caddr_t buf = sc->sc_mem;
        caddr_t bptr, from = fromv;
        int xfer;

        bptr = buf + ((boff << 1) & ~0x1f);
        boff &= 0xf;
        xfer = min(len, 16 - boff);
        while (len > 0) {
                memcpy(bptr + boff, from, xfer);
                from += xfer;
                bptr += 32;
                boff = 0;
                len -= xfer;
                xfer = min(len, 16);
        }
}

static void
lance_copyfrombuf_gap16(struct lance_softc *sc, void *tov, int boff, int len)
{
        volatile caddr_t buf = sc->sc_mem;
        caddr_t bptr, to = tov;
        int xfer;

        bptr = buf + ((boff << 1) & ~0x1f);
        boff &= 0xf;
        xfer = min(len, 16 - boff);
        while (len > 0) {
                memcpy(to, bptr + boff, xfer);
                to += xfer;
                bptr += 32;
                boff = 0;
                len -= xfer;
                xfer = min(len, 16);
        }
}

static void
lance_zerobuf_gap16(struct lance_softc *sc, int boff, int len)
{
        volatile caddr_t buf = sc->sc_mem;
        caddr_t bptr;
        int xfer;

        bptr = buf + ((boff << 1) & ~0x1f);
        boff &= 0xf;
        xfer = min(len, 16 - boff);
        while (len > 0) {
                memset(bptr + boff, 0, xfer);
                bptr += 32;
                boff = 0;
                len -= xfer;
                xfer = min(len, 16);
        }
}
#endif /* Example only */