NetBSD/sys/dev/ic/lemac.c

/* $NetBSD: lemac.c,v 1.4 1998/03/29 22:08:03 mycroft Exp $ */

/*-
 * Copyright (c) 1994, 1995, 1997 Matt Thomas <matt@3am-software.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software withough specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

/*
 * DEC EtherWORKS 3 Ethernet Controllers
 *
 * Written by Matt Thomas
 * BPF support code stolen directly from if_ec.c
 *
 *   This driver supports the LEMAC DE203/204/205 cards.
 */

#include "rnd.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/device.h>
#if NRND > 0
#include <sys/rnd.h>
#endif

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

#ifdef INET
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/if_inarp.h>
#endif

#ifdef NS
#include <netns/ns.h>
#include <netns/ns_if.h>
#endif

#include <machine/bus.h>

#include <dev/ic/lemacreg.h>
#include <dev/ic/lemacvar.h>
#if 0
#include <i386/isa/decether.h>
#endif

#include <vm/vm.h>

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

static void lemac_init(lemac_softc_t *sc);
static void lemac_ifstart(struct ifnet *ifp);
static void lemac_reset(lemac_softc_t *sc);
static void lemac_rne_intr(lemac_softc_t *sc);
static void lemac_tne_intr(lemac_softc_t *sc);
static void lemac_txd_intr(lemac_softc_t *sc, unsigned cs_value);
static void lemac_rxd_intr(lemac_softc_t *sc, unsigned cs_value);
static int  lemac_read_eeprom(lemac_softc_t *sc);
static void lemac_init_adapmem(lemac_softc_t *sc);

static const u_int16_t lemac_allmulti_mctbl[16] =  {
    0xFFFFU, 0xFFFFU, 0xFFFFU, 0xFFFFU,
    0xFFFFU, 0xFFFFU, 0xFFFFU, 0xFFFFU,
    0xFFFFU, 0xFFFFU, 0xFFFFU, 0xFFFFU,
    0xFFFFU, 0xFFFFU, 0xFFFFU, 0xFFFFU,
};

/*
 * Some tuning/monitoring variables.
 */
unsigned lemac_txmax = 16;

static void
lemac_rxd_intr(
    lemac_softc_t *sc,
    unsigned cs_value)
{
    /*
     * Handle CS_RXD (Receiver disabled) here.
     *
     * Check Free Memory Queue Count. If not equal to zero
     * then just turn Receiver back on. If it is equal to
     * zero then check to see if transmitter is disabled.
     * Process transmit TXD loop once more.  If all else
     * fails then do software init (0xC0 to EEPROM Init)
     * and rebuild Free Memory Queue.
     */

    sc->sc_cntrs.cntr_rxd_intrs++;

    /*
     *  Re-enable Receiver.
     */

    cs_value &= ~LEMAC_CS_RXD;
    LEMAC_OUTB(sc, LEMAC_REG_CS, cs_value);

    if (LEMAC_INB(sc, LEMAC_REG_FMC) > 0)
	return;

    if (cs_value & LEMAC_CS_TXD)
	lemac_txd_intr(sc, cs_value);

    if ((LEMAC_INB(sc, LEMAC_REG_CS) & LEMAC_CS_RXD) == 0)
	return;

    printf("%s: fatal RXD error, attempting recovery\n", sc->sc_if.if_xname);

    lemac_reset(sc);
    if (sc->sc_if.if_flags & IFF_UP) {
	lemac_init(sc);
	return;
    }

    /*
     *  Error during initializion.  Mark card as disabled.
     */
    printf("%s: recovery failed -- board disabled\n", sc->sc_if.if_xname);
}

static void
lemac_tne_intr(
    lemac_softc_t *sc)
{
    unsigned txcount = LEMAC_INB(sc, LEMAC_REG_TDC);

    sc->sc_cntrs.cntr_tne_intrs++;
    while (txcount-- > 0) {
	unsigned txsts = LEMAC_INB(sc, LEMAC_REG_TDQ);
	sc->sc_if.if_opackets++;		/* another one done */
	if ((txsts & (LEMAC_TDQ_LCL|LEMAC_TDQ_NCL))
	        || (txsts & LEMAC_TDQ_COL) == LEMAC_TDQ_EXCCOL) {
	    if (txsts & LEMAC_TDQ_NCL)
		sc->sc_flags &= ~LEMAC_LINKUP;
	    sc->sc_if.if_oerrors++;
	} else {
	    sc->sc_flags |= LEMAC_LINKUP;
	    if ((txsts & LEMAC_TDQ_COL) != LEMAC_TDQ_NOCOL)
		sc->sc_if.if_collisions++;
	}
    }
    sc->sc_if.if_flags &= ~IFF_OACTIVE;
    lemac_ifstart(&sc->sc_if);
}

static void
lemac_txd_intr(
    lemac_softc_t *sc,
    unsigned cs_value)
{
    /*
     * Read transmit status, remove transmit buffer from
     * transmit queue and place on free memory queue,
     * then reset transmitter.
     * Increment appropriate counters.
     */

    sc->sc_cntrs.cntr_txd_intrs++;
    if (sc->sc_txctl & LEMAC_TX_STP) {
	sc->sc_if.if_oerrors++;
	/* return page to free queue */
	LEMAC_OUTB(sc, LEMAC_REG_FMQ, LEMAC_INB(sc, LEMAC_REG_TDQ));
    }

    /* Turn back on transmitter if disabled */
    LEMAC_OUTB(sc, LEMAC_REG_CS, cs_value & ~LEMAC_CS_TXD);
    sc->sc_if.if_flags &= ~IFF_OACTIVE;
}

static int
lemac_read_eeprom(
    lemac_softc_t *sc)
{
    int	word_off, cksum;

    u_char *ep;

    cksum = 0;
    ep = sc->sc_eeprom;
    for (word_off = 0; word_off < LEMAC_EEP_SIZE / 2; word_off++) {
	LEMAC_OUTB(sc, LEMAC_REG_PI1, word_off);
	LEMAC_OUTB(sc, LEMAC_REG_IOP, LEMAC_IOP_EEREAD);

	DELAY(LEMAC_EEP_DELAY);

	*ep = LEMAC_INB(sc, LEMAC_REG_EE1);	cksum += *ep++;
	*ep = LEMAC_INB(sc, LEMAC_REG_EE2);	cksum += *ep++;
    }

    /*
     *  Set up Transmit Control Byte for use later during transmit.
     */

    sc->sc_txctl |= LEMAC_TX_FLAGS;

    if ((sc->sc_eeprom[LEMAC_EEP_SWFLAGS] & LEMAC_EEP_SW_SQE) == 0)
	sc->sc_txctl &= ~LEMAC_TX_SQE;

    if (sc->sc_eeprom[LEMAC_EEP_SWFLAGS] & LEMAC_EEP_SW_LAB)
	sc->sc_txctl |= LEMAC_TX_LAB;

    bcopy(&sc->sc_eeprom[LEMAC_EEP_PRDNM], sc->sc_prodname, LEMAC_EEP_PRDNMSZ);
    sc->sc_prodname[LEMAC_EEP_PRDNMSZ] = '\0';

    return cksum % 256;
}

static void
lemac_init_adapmem(
    lemac_softc_t *sc)
{
    int pg, conf;

    conf = LEMAC_INB(sc, LEMAC_REG_CNF);

    if ((sc->sc_eeprom[LEMAC_EEP_SETUP] & LEMAC_EEP_ST_DRAM) == 0) {
	sc->sc_lastpage = 63;
	conf &= ~LEMAC_CNF_DRAM;
    } else {
	sc->sc_lastpage = 127;
	conf |= LEMAC_CNF_DRAM;
    }

    LEMAC_OUTB(sc, LEMAC_REG_CNF, conf);

    for (pg = 1; pg <= sc->sc_lastpage; pg++)
	LEMAC_OUTB(sc, LEMAC_REG_FMQ, pg);
}

static void
lemac_input(
    lemac_softc_t *sc,
    bus_addr_t offset,
    size_t length)
{
    struct ether_header eh;
    struct mbuf *m;

    if (length - sizeof(eh) > ETHERMTU
	    || length - sizeof(eh) < ETHERMIN) {
	sc->sc_if.if_ierrors++;
	return;
    }
    if (LEMAC_USE_PIO_MODE(sc)) {
	LEMAC_INSB(sc, LEMAC_REG_DAT, sizeof(eh), (void *) &eh);
    } else {
	LEMAC_GETBUF16(sc, offset, sizeof(eh) / 2, (void *) &eh);
    }

    /*
     * If this is single cast but not to us
     * drop it!
     */
    if ((eh.ether_dhost[0] & 1) == 0
#if NBPFILTER > 0
	    && (sc->sc_if.if_flags & IFF_PROMISC) == 0
#endif
	    && !LEMAC_ADDREQUAL(eh.ether_dhost, LLADDR(sc->sc_if.if_sadl)))
	return;

    MGETHDR(m, M_DONTWAIT, MT_DATA);
    if (m == NULL) {
	sc->sc_if.if_ierrors++;
	return;
    }
    if (length + 2 > MHLEN) {
	MCLGET(m, M_DONTWAIT);
	if ((m->m_flags & M_EXT) == 0) {
	    m_free(m);
	    sc->sc_if.if_ierrors++;
	    return;
	}
    }
    m->m_data += 2;
    bcopy((caddr_t)&eh, m->m_data, sizeof(eh));
    if (LEMAC_USE_PIO_MODE(sc)) {
	LEMAC_INSB(sc, LEMAC_REG_DAT, length - sizeof(eh),
		   mtod(m, caddr_t) + sizeof(eh));
    } else {
	LEMAC_GETBUF16(sc, offset + sizeof(eh), (length - sizeof(eh)) / 2,
		      (void *) (mtod(m, caddr_t) + sizeof(eh)));
	if (length & 1)
	    m->m_data[length - 1] = LEMAC_GET8(sc, offset + length - 1);
    }
#if NBPFILTER > 0
    if (sc->sc_if.if_bpf != NULL) {
	m->m_pkthdr.len = m->m_len = length;
	bpf_mtap(sc->sc_if.if_bpf, m);
    }
    /*
     * If this is single cast but not to us
     * drop it!
     */
    if ((eh.ether_dhost[0] & 1) == 0
	   && !LEMAC_ADDREQUAL(eh.ether_dhost, LLADDR(sc->sc_if.if_sadl))) {
	m_freem(m);
	return;
    }
#endif
    m->m_pkthdr.len = m->m_len = length - sizeof(eh);
    m->m_data += sizeof(eh);
    m->m_pkthdr.rcvif = &sc->sc_if;
    ether_input(&sc->sc_if, &eh, m);
}

static void
lemac_rne_intr(
    lemac_softc_t *sc)
{
    int rxcount;

    sc->sc_cntrs.cntr_rne_intrs++;
    rxcount = LEMAC_INB(sc, LEMAC_REG_RQC);
    while (rxcount--) {
	unsigned rxpg = LEMAC_INB(sc, LEMAC_REG_RQ);
	u_int32_t rxlen;
	
	sc->sc_if.if_ipackets++;
	if (LEMAC_USE_PIO_MODE(sc)) {
	    LEMAC_OUTB(sc, LEMAC_REG_IOP, rxpg);
	    LEMAC_OUTB(sc, LEMAC_REG_PI1, 0);
	    LEMAC_OUTB(sc, LEMAC_REG_PI2, 0);
	    LEMAC_INSB(sc, LEMAC_REG_DAT, sizeof(rxlen), (void *) &rxlen);
	} else {
	    LEMAC_OUTB(sc, LEMAC_REG_MPN, rxpg);
	    rxlen = LEMAC_GET32(sc, 0);
	}
	if (rxlen & LEMAC_RX_OK) {
	    sc->sc_flags |= LEMAC_LINKUP;
	    /*
	     * Get receive length - subtract out checksum.
	     */
	    rxlen = ((rxlen >> 8) & 0x7FF) - 4;
	    lemac_input(sc, sizeof(rxlen), rxlen);
	} else {
	    sc->sc_if.if_ierrors++;
	}
	LEMAC_OUTB(sc, LEMAC_REG_FMQ, rxpg);  /* Return this page to Free Memory Queue */
    }  /* end while (recv_count--) */
    
    return;
}

/*
 *  This is the standard method of reading the DEC Address ROMS.
 *  I don't understand it but it does work.
 */
static int
lemac_read_macaddr(
    unsigned char *hwaddr,
    const bus_space_tag_t iot,
    const bus_space_handle_t ioh,
    const bus_addr_t ioreg,
    int skippat)
{
    int cksum, rom_cksum;
    unsigned char addrbuf[6];
    
    if (!skippat) {
	int idx, idx2, found, octet;
	static u_char testpat[] = { 0xFF, 0, 0x55, 0xAA, 0xFF, 0, 0x55, 0xAA };
	idx2 = found = 0;
    
	for (idx = 0; idx < 32; idx++) {
	    octet = bus_space_read_1(iot, ioh, ioreg);
	    
	    if (octet == testpat[idx2]) {
		if (++idx2 == sizeof(testpat)) {
		    ++found;
		    break;
		}
	    } else {
		idx2 = 0;
	    }
	}
	
	if (!found)
	    return -1;
    }

    if (hwaddr == NULL)
	hwaddr = addrbuf;

    cksum = 0;
    hwaddr[0] = bus_space_read_1(iot, ioh, ioreg);
    hwaddr[1] = bus_space_read_1(iot, ioh, ioreg);

    /* hardware adddress can't be multicast */
    if (hwaddr[0] & 1)
	return -1;

    cksum = *(u_short *) &hwaddr[0];

    hwaddr[2] = bus_space_read_1(iot, ioh, ioreg);
    hwaddr[3] = bus_space_read_1(iot, ioh, ioreg);
    cksum *= 2;
    if (cksum > 65535) cksum -= 65535;
    cksum += *(u_short *) &hwaddr[2];
    if (cksum > 65535) cksum -= 65535;

    hwaddr[4] = bus_space_read_1(iot, ioh, ioreg);
    hwaddr[5] = bus_space_read_1(iot, ioh, ioreg);
    cksum *= 2;
    if (cksum > 65535) cksum -= 65535;
    cksum += *(u_short *) &hwaddr[4];
    if (cksum >= 65535) cksum -= 65535;

    /* 00-00-00 is an illegal OUI */
    if (hwaddr[0] == 0 && hwaddr[1] == 0 && hwaddr[2] == 0)
	return -1;

    rom_cksum = bus_space_read_1(iot, ioh, ioreg);
    rom_cksum |= bus_space_read_1(iot, ioh, ioreg) << 8;
	
    if (cksum != rom_cksum)
	return -1;
    return 0;
}

static void
lemac_multicast_op(
    u_int16_t *mctbl,
    const u_char *mca,
    int enable)
{
    u_int idx, bit, crc = 0xFFFFFFFFUL;

    for (idx = 0; idx < 6; idx++) {
	crc ^= (*mca++) << 0;
        for (bit = 0; bit < 8; bit++)
            crc = (crc >> 1) ^ ((crc & 1) ? LEMAC_CRC32_POLY : 0);
    }
    /*
     * The following two lines convert the N bit index into a longword index
     * and a longword mask.  
     */
#if LEMAC_MCTBL_BITS < 0
    crc >>= (32 + LEMAC_MCTBL_BITS);
    crc &= (1 << -LEMAC_MCTBL_BITS) - 1;
#else
    crc &= (1 << LEMAC_MCTBL_BITS) - 1;
#endif
    bit = 1 << (crc & 0x0F);
    idx = crc >> 4;

    /*
     * Set or clear hash filter bit in our table.
     */
    if (enable) {
	mctbl[idx] |= bit;		/* Set Bit */
    } else {
	mctbl[idx] &= ~bit;		/* Clear Bit */
    }
}

static void
lemac_multicast_filter(
    lemac_softc_t *sc)
{
    struct ether_multistep step;
    struct ether_multi *enm;

    bzero(sc->sc_mctbl, LEMAC_MCTBL_BITS / 8);

    lemac_multicast_op(sc->sc_mctbl, etherbroadcastaddr, TRUE);

    ETHER_FIRST_MULTI(step, &sc->sc_ec, enm);
    while (enm != NULL) {
	if (!LEMAC_ADDREQUAL(enm->enm_addrlo, enm->enm_addrhi)) {
	    sc->sc_flags |= LEMAC_ALLMULTI;
	    sc->sc_if.if_flags |= IFF_ALLMULTI;
	    return;
	}
	lemac_multicast_op(sc->sc_mctbl, enm->enm_addrlo, TRUE);
	ETHER_NEXT_MULTI(step, enm);
    }
    sc->sc_flags &= ~LEMAC_ALLMULTI;
    sc->sc_if.if_flags &= ~IFF_ALLMULTI;
}

/* 
 * Do a hard reset of the board;
 */
static void
lemac_reset(
    lemac_softc_t * const sc)
{
    unsigned data;

    /*
     * Initialize board..
     */
    sc->sc_flags &= ~LEMAC_LINKUP;
    sc->sc_if.if_flags &= ~IFF_OACTIVE;
    LEMAC_INTR_DISABLE(sc);

    LEMAC_OUTB(sc, LEMAC_REG_IOP, LEMAC_IOP_EEINIT);
    DELAY(LEMAC_EEP_DELAY);

    /*
     * Read EEPROM information.  NOTE - the placement of this function
     * is important because functions hereafter may rely on information
     * read from the EEPROM.
     */
    if ((data = lemac_read_eeprom(sc)) != LEMAC_EEP_CKSUM) { 
	printf("%s: reset: EEPROM checksum failed (0x%x)\n",
	       sc->sc_if.if_xname, data);
	return;
    }

    /*
     * Update the control register to reflect the media choice
     */
    data = LEMAC_INB(sc, LEMAC_REG_CTL);
    if ((data & (LEMAC_CTL_APD|LEMAC_CTL_PSL)) != sc->sc_ctlmode) {
	data &= ~(LEMAC_CTL_APD|LEMAC_CTL_PSL);
	data |= sc->sc_ctlmode;
	LEMAC_OUTB(sc, LEMAC_REG_CTL, data);
    }

    /*
     *  Force to 2K mode if not already configured.
     */

    data = LEMAC_INB(sc, LEMAC_REG_MBR);
    if (LEMAC_IS_2K_MODE(data)) {
	sc->sc_flags |= LEMAC_2K_MODE;
    } else if (LEMAC_IS_64K_MODE(data)) {
	data = (((data * 2) & 0xF) << 4);
	sc->sc_flags |= LEMAC_WAS_64K_MODE;
	LEMAC_OUTB(sc, LEMAC_REG_MBR, data);
    } else if (LEMAC_IS_32K_MODE(data)) {
	data = ((data & 0xF) << 4);
	sc->sc_flags |= LEMAC_WAS_32K_MODE;
	LEMAC_OUTB(sc, LEMAC_REG_MBR, data);
    } else {
	sc->sc_flags |= LEMAC_PIO_MODE;
	/* PIO mode */
    }

    /*
     *  Initialize Free Memory Queue, Init mcast table with broadcast.
     */

    lemac_init_adapmem(sc);
    sc->sc_flags |= LEMAC_ALIVE;
}

static void
lemac_init(
    lemac_softc_t * const sc)
{
    if ((sc->sc_flags & LEMAC_ALIVE) == 0)
	return;

    /*
     * If the interface has the up flag
     */
    if (sc->sc_if.if_flags & IFF_UP) {
	int saved_cs = LEMAC_INB(sc, LEMAC_REG_CS);
	LEMAC_OUTB(sc, LEMAC_REG_CS, saved_cs | (LEMAC_CS_TXD | LEMAC_CS_RXD));
	LEMAC_OUTB(sc, LEMAC_REG_PA0, LLADDR(sc->sc_if.if_sadl)[0]);
	LEMAC_OUTB(sc, LEMAC_REG_PA1, LLADDR(sc->sc_if.if_sadl)[1]);
	LEMAC_OUTB(sc, LEMAC_REG_PA2, LLADDR(sc->sc_if.if_sadl)[2]);
	LEMAC_OUTB(sc, LEMAC_REG_PA3, LLADDR(sc->sc_if.if_sadl)[3]);
	LEMAC_OUTB(sc, LEMAC_REG_PA4, LLADDR(sc->sc_if.if_sadl)[4]);
	LEMAC_OUTB(sc, LEMAC_REG_PA5, LLADDR(sc->sc_if.if_sadl)[5]);

	LEMAC_OUTB(sc, LEMAC_REG_IC, LEMAC_INB(sc, LEMAC_REG_IC) | LEMAC_IC_IE);

	if (sc->sc_if.if_flags & IFF_PROMISC) {
	    LEMAC_OUTB(sc, LEMAC_REG_CS, LEMAC_CS_MCE | LEMAC_CS_PME);
	} else {
	    LEMAC_INTR_DISABLE(sc);
	    lemac_multicast_filter(sc);
	    if (sc->sc_flags & LEMAC_ALLMULTI)
		bcopy(lemac_allmulti_mctbl, sc->sc_mctbl, sizeof(sc->sc_mctbl));
	    if (LEMAC_USE_PIO_MODE(sc)) {
		LEMAC_OUTB(sc, LEMAC_REG_IOP, 0);
		LEMAC_OUTB(sc, LEMAC_REG_PI1, LEMAC_MCTBL_OFF & 0xFF);
		LEMAC_OUTB(sc, LEMAC_REG_PI2, LEMAC_MCTBL_OFF >> 8);
		LEMAC_OUTSB(sc, LEMAC_REG_DAT, sizeof(sc->sc_mctbl), (void *) sc->sc_mctbl);
	    } else {
		LEMAC_OUTB(sc, LEMAC_REG_MPN, 0);
		LEMAC_PUTBUF8(sc, LEMAC_MCTBL_OFF, sizeof(sc->sc_mctbl), (void *) sc->sc_mctbl);
	    }

	    LEMAC_OUTB(sc, LEMAC_REG_CS, LEMAC_CS_MCE);
	}

	LEMAC_OUTB(sc, LEMAC_REG_CTL, LEMAC_INB(sc, LEMAC_REG_CTL) ^ LEMAC_CTL_LED);

	LEMAC_INTR_ENABLE(sc);
	sc->sc_if.if_flags |= IFF_RUNNING;
	lemac_ifstart(&sc->sc_if);
    } else {
	LEMAC_OUTB(sc, LEMAC_REG_CS, LEMAC_CS_RXD|LEMAC_CS_TXD);

	LEMAC_INTR_DISABLE(sc);
	sc->sc_if.if_flags &= ~IFF_RUNNING;
    }
}

static void 
lemac_ifstart(
    struct ifnet *ifp)
{
    lemac_softc_t * const sc = LEMAC_IFP_TO_SOFTC(ifp);
    struct ifqueue * const ifq = &ifp->if_snd;

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

    LEMAC_INTR_DISABLE(sc);

    while (ifq->ifq_head != NULL) {
	struct mbuf *m;
	struct mbuf *m0;
	int tx_pg;

	if ((sc->sc_csr.csr_tqc = LEMAC_INB(sc, LEMAC_REG_TQC)) >= lemac_txmax) {
	    sc->sc_cntrs.cntr_txfull++;
	    ifp->if_flags |= IFF_OACTIVE;
	    break;
	}

	/*
	 * get free memory page
	 */
	tx_pg = sc->sc_csr.csr_fmq = LEMAC_INB(sc, LEMAC_REG_FMQ);
	/*
	 * Check for good transmit page.
	 */
	if (tx_pg == 0 || tx_pg > sc->sc_lastpage) {
	    sc->sc_cntrs.cntr_txnospc++;
	    ifp->if_flags |= IFF_OACTIVE;
	    break;
	}

	IF_DEQUEUE(ifq, m);

	/*
	 * The first four bytes of each transmit buffer are for
	 * control information.  The first byte is the control
	 * byte, then the length (why not word aligned??), then
	 * the offset to the buffer.
	 */

	if (LEMAC_USE_PIO_MODE(sc)) {
	    LEMAC_OUTB(sc, LEMAC_REG_IOP, tx_pg);	/* Shift 2K window. */
	    LEMAC_OUTB(sc, LEMAC_REG_PI1, 0);
	    LEMAC_OUTB(sc, LEMAC_REG_PI2, 0);
	    LEMAC_OUTB(sc, LEMAC_REG_DAT, sc->sc_txctl);
	    LEMAC_OUTB(sc, LEMAC_REG_DAT, (m->m_pkthdr.len >> 0) & 0xFF);
	    LEMAC_OUTB(sc, LEMAC_REG_DAT, (m->m_pkthdr.len >> 8) & 0xFF);
	    LEMAC_OUTB(sc, LEMAC_REG_DAT, LEMAC_TX_HDRSZ);
	    for (m0 = m; m0 != NULL; m0 = m0->m_next)
		LEMAC_OUTSB(sc, LEMAC_REG_DAT, m0->m_len, m0->m_data);
	} else {
	    bus_size_t txoff = /* (mtod(m, u_int32_t) & (sizeof(u_int32_t) - 1)) + */ LEMAC_TX_HDRSZ;
	    LEMAC_OUTB(sc, LEMAC_REG_MPN, tx_pg);	/* Shift 2K window. */
	    LEMAC_PUT8(sc, 0, sc->sc_txctl);
	    LEMAC_PUT8(sc, 1, (m->m_pkthdr.len >> 0) & 0xFF);
	    LEMAC_PUT8(sc, 2, (m->m_pkthdr.len >> 8) & 0xFF);
	    LEMAC_PUT8(sc, 3, txoff);

	    /*
	     * Copy the packet to the board
	     */
	    for (m0 = m; m0 != NULL; m0 = m0->m_next) {
#if 0
		LEMAC_PUTBUF8(sc, txoff, m0->m_len, m0->m_data);
		txoff += m0->m_len;
#else
		const u_int8_t *cp = m0->m_data;
		int len = m0->m_len;
#if 0
		if ((txoff & 3) == (((long)cp) & 3) && len >= 4) {
		    if (txoff & 3) {
			int alen = (~txoff & 3);
			LEMAC_PUTBUF8(sc, txoff, alen, cp);
			cp += alen; txoff += alen; len -= alen;
		    }
		    if (len >= 4) {
			LEMAC_PUTBUF32(sc, txoff, len / 4, cp);
			cp += len & ~3; txoff += len & ~3; len &= 3;
		    }
		}
#endif
		if ((txoff & 1) == (((long)cp) & 1) && len >= 2) {
		    if (txoff & 1) {
			int alen = (~txoff & 1);
			LEMAC_PUTBUF8(sc, txoff, alen, cp);
			cp += alen; txoff += alen; len -= alen;
		    }
		    if (len >= 2) {
			LEMAC_PUTBUF16(sc, txoff, len / 2, (void *) cp);
			cp += len & ~1; txoff += len & ~1; len &= 1;
		    }
		}
		if (len > 0) {
		    LEMAC_PUTBUF8(sc, txoff, len, cp);
		    txoff += len;
		}
#endif
	    }
	}

	LEMAC_OUTB(sc, LEMAC_REG_TQ, tx_pg);	/* tell chip to transmit this packet */
#if NBPFILTER > 0
	if (sc->sc_if.if_bpf != NULL)
	    bpf_mtap(sc->sc_if.if_bpf, m);
#endif
	m_freem(m);			/* free the mbuf */
    }
    LEMAC_INTR_ENABLE(sc);
}

static int
lemac_ifioctl(
    struct ifnet *ifp,
    u_long cmd,
    caddr_t data)
{
    lemac_softc_t * const sc = LEMAC_IFP_TO_SOFTC(ifp);
    int s;
    int error = 0;

    s = splnet();

    switch (cmd) {
	case SIOCSIFADDR: {
	    struct ifaddr *ifa = (struct ifaddr *)data;

	    ifp->if_flags |= IFF_UP;
	    lemac_init(sc);
	    switch (ifa->ifa_addr->sa_family) {
#ifdef INET
		case AF_INET: {
		    arp_ifinit(&sc->sc_if, ifa);
		    break;
		}
#endif /* INET */

#ifdef NS
		/* This magic copied from if_is.c; I don't use XNS,
		 * so I have no way of telling if this actually
		 * works or not.
		 */
		case AF_NS: {
		    struct ns_addr *ina = &(IA_SNS(ifa)->sns_addr);
		    if (ns_nullhost(*ina)) {
			ina->x_host = *(union ns_host *)LLADDR(ifp->if_sadl);
		    } else {
			bcopy((caddr_t)ina->x_host.c_host,
			      LLADDR(ifp->if_sadl), ifp->if_addrlen);
		    }
		    break;
		}
#endif /* NS */

		default: {
		    break;
		}
	    }
	    break;
	}

	case SIOCSIFFLAGS: {
	    lemac_init(sc);
	    break;
	}

	case SIOCADDMULTI:
	case SIOCDELMULTI: {
	    /*
	     * Update multicast listeners
	     */
	    if (cmd == SIOCADDMULTI)
		error = ether_addmulti((struct ifreq *)data, &sc->sc_ec);
	    else
		error = ether_delmulti((struct ifreq *)data, &sc->sc_ec);

	    if (error == ENETRESET) {

		/* reset multicast filtering */
		lemac_init(sc);
		error = 0;
	    }
	    break;
	}

	case SIOCSIFMEDIA:
	case SIOCGIFMEDIA: {
	    error = ifmedia_ioctl(ifp, (struct ifreq *)data,
				  &sc->sc_ifmedia, cmd);
	    break;
	}

	default: {
	    error = EINVAL;
	    break;
	}
    }

    splx(s);
    return error;
}

static int
lemac_ifmedia_change(
    struct ifnet * const ifp)
{
    lemac_softc_t * const sc = LEMAC_IFP_TO_SOFTC(ifp);
    unsigned new_ctl;

    switch (IFM_SUBTYPE(sc->sc_ifmedia.ifm_media)) {
	case IFM_10_T: new_ctl = LEMAC_CTL_APD; break;
	case IFM_10_2:
	case IFM_10_5: new_ctl = LEMAC_CTL_APD|LEMAC_CTL_PSL; break;
	case IFM_AUTO: new_ctl = 0; break;
	default:       return EINVAL;
    }
    if (sc->sc_ctlmode != new_ctl) {
	sc->sc_ctlmode = new_ctl;
	lemac_reset(sc);
	if (sc->sc_if.if_flags & IFF_UP)
	    lemac_init(sc);
    }
    return 0;
}

/*
 * Media status callback
 */
static void
lemac_ifmedia_status(
    struct ifnet * const ifp,
    struct ifmediareq *req)
{
    lemac_softc_t *sc = LEMAC_IFP_TO_SOFTC(ifp);
    unsigned data = LEMAC_INB(sc, LEMAC_REG_CNF);

    req->ifm_status = IFM_AVALID;
    if (sc->sc_flags & LEMAC_LINKUP)
	req->ifm_status |= IFM_ACTIVE;

    if (sc->sc_ctlmode & LEMAC_CTL_APD) {
	if (sc->sc_ctlmode & LEMAC_CTL_PSL) {
	    req->ifm_active = IFM_10_5;
	} else {
	    req->ifm_active = IFM_10_T;
	}
    } else {
	/*
	 * The link bit of the configuration register reflects the
	 * current media choice when auto-port is enabled.
	 */
	if (data & LEMAC_CNF_NOLINK) {
	    req->ifm_active = IFM_10_5;
	} else {
	    req->ifm_active = IFM_10_T;
	}
    }

    req->ifm_active |= IFM_ETHER;
}

int
lemac_port_check(
    const bus_space_tag_t iot,
    const bus_space_handle_t ioh)
{
    unsigned char hwaddr[6];

    if (lemac_read_macaddr(hwaddr, iot, ioh, LEMAC_REG_APD, 0) == 0)
	return 1;
    if (lemac_read_macaddr(hwaddr, iot, ioh, LEMAC_REG_APD, 1) == 0)
	return 1;
    return 0;
}

void
lemac_info_get(
    const bus_space_tag_t iot,
    const bus_space_handle_t ioh,
    bus_addr_t *maddr_p,
    bus_size_t *msize_p,
    int *irq_p)
{
    unsigned data;

    *irq_p = LEMAC_DECODEIRQ(bus_space_read_1(iot, ioh, LEMAC_REG_IC) & LEMAC_IC_IRQMSK);

    data = bus_space_read_1(iot, ioh, LEMAC_REG_MBR);
    if (LEMAC_IS_2K_MODE(data)) {
	*maddr_p = data * (2 * 1024) + (512 * 1024);
	*msize_p =  2 * 1024;
    } else if (LEMAC_IS_64K_MODE(data)) {
	*maddr_p = data * 64 * 1024;
	*msize_p = 64 * 1024;
    } else if (LEMAC_IS_32K_MODE(data)) {
	*maddr_p = data * 32 * 1024;
	*msize_p = 32* 1024;
    } else {
	*maddr_p = 0;
	*msize_p = 0;
    }
}

/*
 * What to do upon receipt of an interrupt.
 */
int
lemac_intr(
    void *arg)
{
    lemac_softc_t * const sc = arg;
    int cs_value;

    LEMAC_INTR_DISABLE(sc);	/* Mask interrupts */

    /*
     * Determine cause of interrupt.  Receive events take
     * priority over Transmit.
     */

    cs_value = LEMAC_INB(sc, LEMAC_REG_CS);

    /*
     * Check for Receive Queue not being empty.
     * Check for Transmit Done Queue not being empty.
     */

    if (cs_value & LEMAC_CS_RNE)
	lemac_rne_intr(sc);
    if (cs_value & LEMAC_CS_TNE)
	lemac_tne_intr(sc);

    /*
     * Check for Transmitter Disabled.
     * Check for Receiver Disabled.
     */

    if (cs_value & LEMAC_CS_TXD)
	lemac_txd_intr(sc, cs_value);
    if (cs_value & LEMAC_CS_RXD)
	lemac_rxd_intr(sc, cs_value);

    /*
     * Toggle LED and unmask interrupts.
     */

    sc->sc_csr.csr_cs = LEMAC_INB(sc, LEMAC_REG_CS);

    LEMAC_OUTB(sc, LEMAC_REG_CTL, LEMAC_INB(sc, LEMAC_REG_CTL) ^ LEMAC_CTL_LED);
    LEMAC_INTR_ENABLE(sc);		/* Unmask interrupts */

#if NRND > 0
    if (cs_value)
        rnd_add_uint32(&sc->rnd_source, cs_value);
#endif

    return 1;
}

void
lemac_shutdown(
    void *arg)
{
    lemac_reset((lemac_softc_t *) arg);
}

static const char * const lemac_modes[4] = {
    "PIO mode (internal 2KB window)",
    "2KB window",
    "changed 32KB window to 2KB",
    "changed 64KB window to 2KB",
};

void
lemac_ifattach(
    lemac_softc_t *sc)
{
    struct ifnet * const ifp = &sc->sc_if;

    bcopy(sc->sc_dv.dv_xname, ifp->if_xname, IFNAMSIZ);

    lemac_reset(sc);

    (void) lemac_read_macaddr(sc->sc_enaddr, sc->sc_iot, sc->sc_ioh,
			      LEMAC_REG_APD, 0);
	
    printf(": %s\n", sc->sc_prodname);

    printf("%s: address %s, %dKB RAM, %s\n",
	   ifp->if_xname,
	   ether_sprintf(sc->sc_enaddr),
	   sc->sc_lastpage * 2 + 2,
	   lemac_modes[sc->sc_flags & LEMAC_MODE_MASK]);

    ifp->if_baudrate = 10000000;
    ifp->if_softc = (void *) sc;
    ifp->if_start = lemac_ifstart;
    ifp->if_output = ether_output;
    ifp->if_ioctl = lemac_ifioctl;

    ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX
#ifdef IFF_NOTRAILERS
	| IFF_NOTRAILERS
#endif
	| IFF_MULTICAST;

    if (sc->sc_flags & LEMAC_ALIVE) {
	int media;

	if_attach(ifp);
	ether_ifattach(ifp, sc->sc_enaddr);

#if NBPFILTER > 0
	bpfattach(&ifp->if_bpf, ifp, DLT_EN10MB, sizeof(struct ether_header));
#endif

#if NRND > 0
	rnd_attach_source(&sc->rnd_source, sc->sc_dv.dv_xname, RND_TYPE_NET);
#endif

	ifmedia_init(&sc->sc_ifmedia, 0,
		     lemac_ifmedia_change,
		     lemac_ifmedia_status);
	if (sc->sc_prodname[4] == '5')	/* DE205 is UTP/AUI */
	    ifmedia_add(&sc->sc_ifmedia, IFM_ETHER | IFM_AUTO, 0, 0);
	if (sc->sc_prodname[4] != '3')	/* DE204 & 205 have UTP */
	    ifmedia_add(&sc->sc_ifmedia, IFM_ETHER | IFM_10_T, 0, 0);
	if (sc->sc_prodname[4] != '4')	/* DE203 & 205 have BNC */
	    ifmedia_add(&sc->sc_ifmedia, IFM_ETHER | IFM_10_5, 0, 0);
	switch (sc->sc_prodname[4]) {
	    case '3': media = IFM_10_5; break;
	    case '4': media = IFM_10_T; break;
	    default:  media = IFM_AUTO; break;
	}
	ifmedia_set(&sc->sc_ifmedia, IFM_ETHER | media);
    } else {
	printf("%s: disabled due to error\n", ifp->if_xname);
    }
}