/*      $NetBSD: lance.c,v 1.62 2024/11/17 09:28:34 hannken Exp $       */

/*-
 * 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.
 *
 *      @(#)if_le.c     8.2 (Berkeley) 11/16/93
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: lance.c,v 1.62 2024/11/17 09:28:34 hannken Exp $");

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

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

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

#if defined(_KERNEL_OPT)
#include "opt_ddb.h"
#endif

#ifdef DDB
#define integrate
#define hide
#else
#define integrate       static inline
#define hide            static
#endif

integrate struct mbuf *lance_get(struct lance_softc *, int, int);

hide bool lance_shutdown(device_t, int);

int lance_mediachange(struct ifnet *);
void lance_mediastatus(struct ifnet *, struct ifmediareq *);

static inline uint16_t ether_cmp(void *, void *);

void lance_stop(struct ifnet *, int);
int lance_ioctl(struct ifnet *, u_long, void *);
void lance_watchdog(struct ifnet *);

/*
 * Compare two Ether/802 addresses for equality, inlined and
 * unrolled for speed.  Use this like memcmp().
 *
 * XXX: Add <machine/inlines.h> for stuff like this?
 * XXX: or maybe add it to libkern.h instead?
 *
 * "I'd love to have an inline assembler version of this."
 * XXX: Who wanted that? mycroft?  I wrote one, but this
 * version in C is as good as hand-coded assembly. -gwr
 *
 * Please do NOT tweak this without looking at the actual
 * assembly code generated before and after your tweaks!
 */
static inline uint16_t
ether_cmp(void *one, void *two)
{
        uint16_t *a = (uint16_t *)one;
        uint16_t *b = (uint16_t *)two;
        uint16_t diff;

#ifdef  m68k
        /*
         * The post-increment-pointer form produces the best
         * machine code for m68k.  This was carefully tuned
         * so it compiles to just 8 short (2-byte) op-codes!
         */
        diff  = *a++ - *b++;
        diff |= *a++ - *b++;
        diff |= *a++ - *b++;
#else
        /*
         * Most modern CPUs do better with a single expression.
         * Note that short-cut evaluation is NOT helpful here,
         * because it just makes the code longer, not faster!
         */
        diff = (a[0] - b[0]) | (a[1] - b[1]) | (a[2] - b[2]);
#endif

        return (diff);
}

#define ETHER_CMP       ether_cmp

#ifdef LANCE_REVC_BUG
/* Make sure this is short-aligned, for ether_cmp(). */
static uint16_t bcast_enaddr[3] = { ~0, ~0, ~0 };
#endif

void
lance_config(struct lance_softc *sc)
{
        int i, nbuf;
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;

        /* Initialize ifnet structure. */
        strcpy(ifp->if_xname, device_xname(sc->sc_dev));
        ifp->if_softc = sc;
        ifp->if_start = sc->sc_start;
        ifp->if_ioctl = lance_ioctl;
        ifp->if_watchdog = lance_watchdog;
        ifp->if_init = lance_init;
        ifp->if_stop = lance_stop;
        ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
#ifdef LANCE_REVC_BUG
        ifp->if_flags &= ~IFF_MULTICAST;
#endif
        IFQ_SET_READY(&ifp->if_snd);

        /* Initialize ifmedia structures. */
        sc->sc_ethercom.ec_ifmedia = &sc->sc_media;
        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_ETHER | IFM_MANUAL, 0, NULL);
                ifmedia_set(&sc->sc_media, IFM_ETHER | IFM_MANUAL);
        }

        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;
        }

        aprint_normal(": address %s\n", ether_sprintf(sc->sc_enaddr));
        aprint_normal_dev(sc->sc_dev,
            "%d receive buffers, %d transmit buffers\n",
            sc->sc_nrbuf, sc->sc_ntbuf);

        /* Make sure the chip is stopped. */
        lance_stop(ifp, 0);

        /* claim 802.1q capability */
        sc->sc_ethercom.ec_capabilities |= ETHERCAP_VLAN_MTU;
        /* Attach the interface. */
        if_attach(ifp);
        ether_ifattach(ifp, sc->sc_enaddr);

        if (pmf_device_register1(sc->sc_dev, NULL, NULL, lance_shutdown))
                pmf_class_network_register(sc->sc_dev, ifp);
        else
                aprint_error_dev(sc->sc_dev,
                    "couldn't establish power handler\n");

        sc->sc_rbufaddr = malloc(sc->sc_nrbuf * sizeof(int), M_DEVBUF,
                                        M_WAITOK);
        sc->sc_tbufaddr = malloc(sc->sc_ntbuf * sizeof(int), M_DEVBUF,
                                        M_WAITOK);

        rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
                          RND_TYPE_NET, RND_FLAG_DEFAULT);
}

void
lance_reset(struct lance_softc *sc)
{
        int s;

        s = splnet();
        lance_init(&sc->sc_ethercom.ec_if);
        splx(s);
}

void
lance_stop(struct ifnet *ifp, int disable)
{
        struct lance_softc *sc = ifp->if_softc;

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

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

        (*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 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);
        (*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);
                ifp->if_flags |= IFF_RUNNING;
                ifp->if_flags &= ~IFF_OACTIVE;
                ifp->if_timer = 0;
                (*sc->sc_start)(ifp);
        } else
                printf("%s: controller failed to initialize\n",
                        device_xname(sc->sc_dev));
        if (sc->sc_hwinit)
                (*sc->sc_hwinit)(sc);

        return (0);
}

/*
 * 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;

        for (; m; m = n) {
                len = m->m_len;
                if (len == 0) {
                        n = m_free(m);
                        continue;
                }
                (*sc->sc_copytobuf)(sc, mtod(m, void *), boff, len);
                boff += len;
                tlen += len;
                n = m_free(m);
        }
        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.
 */
integrate struct mbuf *
lance_get(struct lance_softc *sc, int boff, int totlen)
{
        struct mbuf *m, *m0, *newm;
        int len;

        MGETHDR(m0, M_DONTWAIT, MT_DATA);
        if (m0 == 0)
                return (0);
        MCLAIM(m0, &sc->sc_ethercom.ec_rx_mowner);
        m_set_rcvif(m0, &sc->sc_ethercom.ec_if);
        m0->m_pkthdr.len = totlen;
        len = MHLEN;
        m = m0;

        while (totlen > 0) {
                if (totlen >= MINCLSIZE) {
                        MCLGET(m, M_DONTWAIT);
                        if ((m->m_flags & M_EXT) == 0)
                                goto bad;
                        len = MCLBYTES;
                }

                if (m == m0) {
                        char *newdata = (char *)
                            ALIGN(m->m_data + sizeof(struct ether_header)) -
                            sizeof(struct ether_header);
                        len -= newdata - m->m_data;
                        m->m_data = newdata;
                }

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

                totlen -= len;
                if (totlen > 0) {
                        MGET(newm, M_DONTWAIT, MT_DATA);
                        if (newm == 0)
                                goto bad;
                        MCLAIM(newm, &sc->sc_ethercom.ec_rx_mowner);
                        len = MLEN;
                        m = m->m_next = newm;
                }
        }

        return (m0);

bad:
        m_freem(m0);
        return (0);
}

/*
 * Pass a packet to the higher levels.
 */
void
lance_read(struct lance_softc *sc, int boff, int len)
{
        struct mbuf *m;
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;
        struct ether_header *eh;

        if (len <= sizeof(struct ether_header) ||
            len > ((sc->sc_ethercom.ec_capenable & ETHERCAP_VLAN_MTU) ?
                ETHER_VLAN_ENCAP_LEN + ETHERMTU + sizeof(struct ether_header) :
                ETHERMTU + sizeof(struct ether_header))) {
#ifdef LEDEBUG
                printf("%s: invalid packet size %d; dropping\n",
                    device_xname(sc->sc_dev), len);
#endif
                if_statinc(ifp, if_ierrors);
                return;
        }

        /* Pull packet off interface. */
        m = lance_get(sc, boff, len);
        if (m == 0) {
                if_statinc(ifp, if_ierrors);
                return;
        }

        eh = mtod(m, struct ether_header *);

#ifdef LANCE_REVC_BUG
        /*
         * The old LANCE (Rev. C) chips have a bug which causes
         * garbage to be inserted in front of the received packet.
         * The work-around is to ignore packets with an invalid
         * destination address (garbage will usually not match).
         * Of course, this precludes multicast support...
         */
        if (ETHER_CMP(eh->ether_dhost, sc->sc_enaddr) &&
            ETHER_CMP(eh->ether_dhost, bcast_enaddr)) {
                m_freem(m);
                return;
        }
#endif

        /*
         * Some lance device does not present IFF_SIMPLEX behavior on multicast
         * packets.  Make sure to drop it if it is from ourselves.
         */
        if (!ETHER_CMP(eh->ether_shost, sc->sc_enaddr)) {
                m_freem(m);
                return;
        }

        /* Pass the packet up. */
        if_percpuq_enqueue(ifp->if_percpuq, m);
}

#undef  ifp

void
lance_watchdog(struct ifnet *ifp)
{
        struct lance_softc *sc = ifp->if_softc;

        log(LOG_ERR, "%s: device timeout\n", device_xname(sc->sc_dev));
        if_statinc(ifp, if_oerrors);

        lance_reset(sc);
}

int
lance_mediachange(struct ifnet *ifp)
{
        struct lance_softc *sc = ifp->if_softc;

        if (sc->sc_mediachange)
                return ((*sc->sc_mediachange)(sc));
        return (0);
}

void
lance_mediastatus(struct ifnet *ifp, struct ifmediareq *ifmr)
{
        struct lance_softc *sc = ifp->if_softc;

        if ((ifp->if_flags & IFF_UP) == 0)
                return;

        ifmr->ifm_status = IFM_AVALID;
        if (sc->sc_havecarrier)
                ifmr->ifm_status |= IFM_ACTIVE;

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

/*
 * Process an ioctl request.
 */
int
lance_ioctl(struct ifnet *ifp, u_long cmd, void *data)
{
        struct lance_softc *sc = ifp->if_softc;
        int s, error = 0;

        s = splnet();

        switch (cmd) {
        default:
                if ((error = ether_ioctl(ifp, cmd, data)) != ENETRESET)
                        break;
                error = 0;
                if (cmd != SIOCADDMULTI && cmd != SIOCDELMULTI)
                        break;
                if (ifp->if_flags & IFF_RUNNING) {
                        /*
                         * Multicast list has changed; set the hardware filter
                         * accordingly.
                         */
                        lance_reset(sc);
                }
                break;

        }

        splx(s);
        return (error);
}

hide bool
lance_shutdown(device_t self, int howto)
{
        struct lance_softc *sc = device_private(self);
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;

        lance_stop(ifp, 0);

        return true;
}

/*
 * Set up the logical address filter.
 */
void
lance_setladrf(struct ethercom *ec, uint16_t *af)
{
        struct ifnet *ifp = &ec->ec_if;
        struct ether_multi *enm;
        uint32_t crc;
        struct ether_multistep step;

        /*
         * 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 (ifp->if_flags & IFF_PROMISC)
                goto allmulti;

        af[0] = af[1] = af[2] = af[3] = 0x0000;

        ETHER_LOCK(ec);
        ETHER_FIRST_MULTI(step, ec, enm);
        while (enm != NULL) {
                if (ETHER_CMP(enm->enm_addrlo, enm->enm_addrhi)) {
                        /*
                         * 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.)
                         */
                        ETHER_UNLOCK(ec);
                        goto allmulti;
                }

                crc = ether_crc32_le(enm->enm_addrlo, ETHER_ADDR_LEN);

                /* Just want the 6 most significant bits. */
                crc >>= 26;

                /* Set the corresponding bit in the filter. */
                af[crc >> 4] |= 1 << (crc & 0xf);

                ETHER_NEXT_MULTI(step, enm);
        }
        ETHER_UNLOCK(ec);
        ifp->if_flags &= ~IFF_ALLMULTI;
        return;

allmulti:
        ifp->if_flags |= IFF_ALLMULTI;
        af[0] = af[1] = af[2] = af[3] = 0xffff;
}

/*
 * 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)
{
        uint8_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)
{
        uint8_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)
{
        uint8_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.
 */

void
lance_copytobuf_gap2(struct lance_softc *sc, void *fromv, int boff, int len)
{
        volatile void *buf = sc->sc_mem;
        void *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;
}

void
lance_copyfrombuf_gap2(struct lance_softc *sc, void *tov, int boff, int len)
{
        volatile void *buf = sc->sc_mem;
        void *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;
}

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

        if ((unsigned int)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.
 */

void
lance_copytobuf_gap16(struct lance_softc *sc, void *fromv, int boff, int len)
{
        volatile uint8_t *buf = sc->sc_mem;
        void *from = fromv;
        uint8_t *bptr;
        int xfer;

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

void
lance_copyfrombuf_gap16(struct lance_softc *sc, void *tov, int boff, int len)
{
        volatile uint8_t *buf = sc->sc_mem;
        void *to = tov;
        uint8_t *bptr;
        int xfer;

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

void
lance_zerobuf_gap16(struct lance_softc *sc, int boff, int len)
{
        volatile uint8_t *buf = sc->sc_mem;
        uint8_t *bptr;
        int xfer;

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