xref: /src/sys/dev/ic/hme.c

/*	$NetBSD: hme.c,v 1.4 1999/12/17 14:37:15 pk Exp $	*/

/*-
 * Copyright (c) 1999 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Paul Kranenburg.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation 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 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.
 */

/*
 * HME Ethernet module driver.
 */

#define HMEDEBUG

#include "opt_inet.h"
#include "opt_ccitt.h"
#include "opt_llc.h"
#include "opt_ns.h"
#include "bpfilter.h"
#include "rnd.h"

#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>
#if NRND > 0
#include <sys/rnd.h>
#endif

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

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

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

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

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

#include <machine/bus.h>

#include <dev/ic/hmereg.h>
#include <dev/ic/hmevar.h>

void		hme_start __P((struct ifnet *));
void		hme_stop __P((struct hme_softc *));
int		hme_ioctl __P((struct ifnet *, u_long, caddr_t));
void		hme_watchdog __P((struct ifnet *));
void		hme_shutdown __P((void *));
void		hme_init __P((struct hme_softc *));
void		hme_meminit __P((struct hme_softc *));
void		hme_mifinit __P((struct hme_softc *));
void		hme_reset __P((struct hme_softc *));
void		hme_setladrf __P((struct hme_softc *));

/* MII methods & callbacks */
static int	hme_mii_readreg __P((struct device *, int, int));
static void	hme_mii_writereg __P((struct device *, int, int, int));
static void	hme_mii_statchg __P((struct device *));

int		hme_mediachange __P((struct ifnet *));
void		hme_mediastatus __P((struct ifnet *, struct ifmediareq *));

struct mbuf	*hme_get __P((struct hme_softc *, int, int));
int		hme_put __P((struct hme_softc *, int, struct mbuf *));
void		hme_read __P((struct hme_softc *, int, int));
int		hme_eint __P((struct hme_softc *, u_int));
int		hme_rint __P((struct hme_softc *));
int		hme_tint __P((struct hme_softc *));

static int	ether_cmp __P((u_char *, u_char *));

/* Default buffer copy routines */
void	hme_copytobuf_contig __P((struct hme_softc *, void *, int, int));
void	hme_copyfrombuf_contig __P((struct hme_softc *, void *, int, int));
void	hme_zerobuf_contig __P((struct hme_softc *, int, int));


void
hme_config(sc)
	struct hme_softc *sc;
{
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	struct mii_data *mii = &sc->sc_mii;
	bus_dma_segment_t seg;
	bus_size_t size;
	int rseg, error;

	/*
	 * HME common initialization.
	 *
	 * hme_softc fields that must be initialized by the front-end:
	 *
	 * the bus tag:
	 *	sc_bustag
	 *
	 * the dma bus tag:
	 *	sc_dmatag
	 *
	 * the bus handles:
	 *	sc_seb		(Shared Ethernet Block registers)
	 *	sc_erx		(Receiver Unit registers)
	 *	sc_etx		(Transmitter Unit registers)
	 *	sc_mac		(MAC registers)
	 *	sc_mif		(Managment Interface registers)
	 *
	 * the maximum bus burst size:
	 *	sc_burst
	 *
	 * (notyet:DMA capable memory for the ring descriptors & packet buffers:
	 *	rb_membase, rb_dmabase)
	 *
	 * the local Ethernet address:
	 *	sc_enaddr
	 *
	 */

	/* Make sure the chip is stopped. */
	hme_stop(sc);


	/*
	 * Allocate descriptors and buffers
	 * XXX - do all this differently.. and more configurably,
	 * eg. use things as `dma_load_mbuf()' on transmit,
	 *     and a pool of `EXTMEM' mbufs (with buffers DMA-mapped
	 *     all the time) on the reveiver side.
	 */
#define _HME_NDESC	32
#define _HME_BUFSZ	1536

	/* Note: the # of descriptors must be a multiple of 16 */
	sc->sc_rb.rb_ntbuf = _HME_NDESC;
	sc->sc_rb.rb_nrbuf = _HME_NDESC;

	/*
	 * Allocate DMA capable memory
	 * Buffer descriptors must be aligned on a 2048 byte boundary;
	 * take this into account when calculating the size. Note that
	 * the maximum number of descriptors (256) occupies 2048 bytes,
	 * so we allocate that much regardless of _HME_NDESC.
	 */
	size =	2048 +					/* TX descriptors */
		2048 +					/* RX descriptors */
		sc->sc_rb.rb_ntbuf * _HME_BUFSZ +	/* TX buffers */
		sc->sc_rb.rb_nrbuf * _HME_BUFSZ;	/* TX buffers */
	if ((error = bus_dmamem_alloc(sc->sc_dmatag, size,
				      2048, 0,
				      &seg, 1, &rseg, BUS_DMA_NOWAIT)) != 0) {
		printf("%s: DMA buffer alloc error %d\n",
			sc->sc_dev.dv_xname, error);
	}
	sc->sc_rb.rb_dmabase = seg.ds_addr;

	/* Map DMA memory in CPU adressable space */
	if ((error = bus_dmamem_map(sc->sc_dmatag, &seg, rseg, size,
				    &sc->sc_rb.rb_membase,
				    BUS_DMA_NOWAIT|BUS_DMA_COHERENT)) != 0) {
		printf("%s: DMA buffer map error %d\n",
			sc->sc_dev.dv_xname, error);
		bus_dmamem_free(sc->sc_dmatag, &seg, rseg);
		return;
	}

#if 0
	/*
	 * Install default copy routines if not supplied.
	 */
	if (sc->sc_copytobuf == NULL)
		sc->sc_copytobuf = hme_copytobuf_contig;

	if (sc->sc_copyfrombuf == NULL)
		sc->sc_copyfrombuf = hme_copyfrombuf_contig;
#endif

	printf(": address %s\n", ether_sprintf(sc->sc_enaddr));

	/* Initialize ifnet structure. */
	bcopy(sc->sc_dev.dv_xname, ifp->if_xname, IFNAMSIZ);
	ifp->if_softc = sc;
	ifp->if_start = hme_start;
	ifp->if_ioctl = hme_ioctl;
	ifp->if_watchdog = hme_watchdog;
	ifp->if_flags =
	    IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS | IFF_MULTICAST;

	/* Initialize ifmedia structures and MII info */
	mii->mii_ifp = ifp;
	mii->mii_readreg = hme_mii_readreg;
	mii->mii_writereg = hme_mii_writereg;
	mii->mii_statchg = hme_mii_statchg;

	ifmedia_init(&mii->mii_media, 0, hme_mediachange, hme_mediastatus);

	hme_mifinit(sc);

	mii_phy_probe(&sc->sc_dev, mii, 0xffffffff,
			MII_PHY_ANY, MII_OFFSET_ANY);

	if (LIST_FIRST(&mii->mii_phys) == NULL) {
		/* No PHY attached */
		ifmedia_add(&sc->sc_media, IFM_ETHER|IFM_MANUAL, 0, NULL);
		ifmedia_set(&sc->sc_media, IFM_ETHER|IFM_MANUAL);
	} else {
		/*
		 * XXX - we can really do the following ONLY if the
		 * phy indeed has the auto negotiation capability!!
		 */
		ifmedia_set(&sc->sc_media, IFM_ETHER|IFM_AUTO);
	}

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

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

	sc->sc_sh = shutdownhook_establish(hme_shutdown, sc);
	if (sc->sc_sh == NULL)
		panic("hme_config: can't establish shutdownhook");

#if 0
	printf("%s: %d receive buffers, %d transmit buffers\n",
	    sc->sc_dev.dv_xname, sc->sc_nrbuf, sc->sc_ntbuf);
	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);
#endif

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

void
hme_reset(sc)
	struct hme_softc *sc;
{
	int s;

	s = splnet();
	hme_init(sc);
	splx(s);
}

void
hme_stop(sc)
	struct hme_softc *sc;
{
	bus_space_tag_t t = sc->sc_bustag;
	bus_space_handle_t seb = sc->sc_seb;
	int n;

	/* Reset transmitter and receiver */
	bus_space_write_4(t, seb, HME_SEBI_RESET,
			  (HME_SEB_RESET_ETX | HME_SEB_RESET_ERX));

	for (n = 0; n < 20; n++) {
		u_int32_t v = bus_space_read_4(t, seb, HME_SEBI_RESET);
		if ((v & (HME_SEB_RESET_ETX | HME_SEB_RESET_ERX)) == 0)
			return;
		DELAY(20);
	}

	printf("%s: hme_stop: reset failed\n", sc->sc_dev.dv_xname);
}

void
hme_meminit(sc)
	struct hme_softc *sc;
{
	bus_addr_t txbufdma, rxbufdma;
	bus_addr_t dma;
	caddr_t p;
	unsigned int ntbuf, nrbuf, i;
	struct hme_ring *hr = &sc->sc_rb;

	p = hr->rb_membase;
	dma = hr->rb_dmabase;

	ntbuf = hr->rb_ntbuf;
	nrbuf = hr->rb_nrbuf;

	/*
	 * Allocate transmit descriptors
	 */
	hr->rb_txd = p;
	hr->rb_txddma = dma;
	p += ntbuf * HME_XD_SIZE;
	dma += ntbuf * HME_XD_SIZE;
	/* We have reserved descriptor space until the next 2048 byte boundary.*/
	dma = (bus_addr_t)roundup((u_long)dma, 2048);
	p = (caddr_t)roundup((u_long)p, 2048);

	/*
	 * Allocate receive descriptors
	 */
	hr->rb_rxd = p;
	hr->rb_rxddma = dma;
	p += nrbuf * HME_XD_SIZE;
	dma += nrbuf * HME_XD_SIZE;
	/* Again move forward to the next 2048 byte boundary.*/
	dma = (bus_addr_t)roundup((u_long)dma, 2048);
	p = (caddr_t)roundup((u_long)p, 2048);


	/*
	 * Allocate transmit buffers
	 */
	hr->rb_txbuf = p;
	txbufdma = dma;
	p += ntbuf * _HME_BUFSZ;
	dma += ntbuf * _HME_BUFSZ;

	/*
	 * Allocate receive buffers
	 */
	hr->rb_rxbuf = p;
	rxbufdma = dma;
	p += nrbuf * _HME_BUFSZ;
	dma += nrbuf * _HME_BUFSZ;

	/*
	 * Initialize transmit buffer descriptors
	 */
	for (i = 0; i < ntbuf; i++) {
		HME_XD_SETADDR(hr->rb_txd, i, txbufdma + i * _HME_BUFSZ);
		HME_XD_SETFLAGS(hr->rb_txd, i, 0);
	}

	/*
	 * Initialize receive buffer descriptors
	 */
	for (i = 0; i < nrbuf; i++) {
		HME_XD_SETADDR(hr->rb_rxd, i, rxbufdma + i * _HME_BUFSZ);
		HME_XD_SETFLAGS(hr->rb_rxd, i,
				HME_XD_OWN | HME_XD_ENCODE_RSIZE(_HME_BUFSZ));
	}

	hr->rb_tdhead = hr->rb_tdtail = 0;
	hr->rb_td_nbusy = 0;
	hr->rb_rdtail = 0;
}

/*
 * Initialization of interface; set up initialization block
 * and transmit/receive descriptor rings.
 */
void
hme_init(sc)
	struct hme_softc *sc;
{
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	bus_space_tag_t t = sc->sc_bustag;
	bus_space_handle_t seb = sc->sc_seb;
	bus_space_handle_t etx = sc->sc_etx;
	bus_space_handle_t erx = sc->sc_erx;
	bus_space_handle_t mac = sc->sc_mac;
	bus_space_handle_t mif = sc->sc_mif;
	u_int8_t *ea;
	u_int32_t v;

	/*
	 * Initialization sequence. The numbered steps below correspond
	 * to the sequence outlined in section 6.3.5.1 in the Ethernet
	 * Channel Engine manual (part of the PCIO manual).
	 * See also the STP2002-STQ document from Sun Microsystems.
	 */

	/* step 1 & 2. Reset the Ethernet Channel */
	hme_stop(sc);

	/* Re-initialize the MIF */
	hme_mifinit(sc);

	/* Call MI reset function if any */
	if (sc->sc_hwreset)
		(*sc->sc_hwreset)(sc);

#if 0
	/* Mask all MIF interrupts, just in case */
	bus_space_write_4(t, mif, HME_MIFI_IMASK, 0xffff);
#endif

	/* step 3. Setup data structures in host memory */
	hme_meminit(sc);

	/* step 4. TX MAC registers & counters */
	bus_space_write_4(t, mac, HME_MACI_NCCNT, 0);
	bus_space_write_4(t, mac, HME_MACI_FCCNT, 0);
	bus_space_write_4(t, mac, HME_MACI_EXCNT, 0);
	bus_space_write_4(t, mac, HME_MACI_LTCNT, 0);

	/* Load station MAC address */
	ea = sc->sc_enaddr;
	bus_space_write_4(t, mac, HME_MACI_MACADDR0, (ea[0] << 8) | ea[1]);
	bus_space_write_4(t, mac, HME_MACI_MACADDR1, (ea[2] << 8) | ea[3]);
	bus_space_write_4(t, mac, HME_MACI_MACADDR2, (ea[4] << 8) | ea[5]);

	/*
	 * Init seed for backoff
	 * (source suggested by manual: low 10 bits of MAC address)
	 */
	v = ((ea[4] << 8) | ea[5]) & 0x3fff;
	bus_space_write_4(t, mac, HME_MACI_RANDSEED, v);


	/* Note: Accepting power-on default for other MAC registers here.. */


	/* step 5. RX MAC registers & counters */
	hme_setladrf(sc);

	/* step 6 & 7. Program Descriptor Ring Base Addresses */
	bus_space_write_4(t, etx, HME_ETXI_RING, sc->sc_rb.rb_txddma);
	bus_space_write_4(t, etx, HME_ETXI_RSIZE, sc->sc_rb.rb_ntbuf);

	bus_space_write_4(t, erx, HME_ERXI_RING, sc->sc_rb.rb_rxddma);


	/* step 8. Global Configuration & Interrupt Mask */
	bus_space_write_4(t, seb, HME_SEBI_IMASK,
			~(
			  /*HME_SEB_STAT_GOTFRAME | HME_SEB_STAT_SENTFRAME |*/
			  HME_SEB_STAT_HOSTTOTX |
			  HME_SEB_STAT_RXTOHOST |
			  HME_SEB_STAT_TXALL |
			  HME_SEB_STAT_TXPERR |
			  HME_SEB_STAT_RCNTEXP |
			  HME_SEB_STAT_ALL_ERRORS ));

	switch (sc->sc_burst) {
	default:
		v = 0;
		break;
	case 16:
		v = HME_SEB_CFG_BURST16;
		break;
	case 32:
		v = HME_SEB_CFG_BURST32;
		break;
	case 64:
		v = HME_SEB_CFG_BURST64;
		break;
	}
	bus_space_write_4(t, seb, HME_SEBI_CFG, v);

	/* step 9. ETX Configuration: use mostly default values */

	/* Enable DMA */
	v = bus_space_read_4(t, etx, HME_ETXI_CFG);
	v |= HME_ETX_CFG_DMAENABLE;
	bus_space_write_4(t, etx, HME_ETXI_CFG, v);

	/* Transmit Descriptor ring size: in increments of 16 */
	bus_space_write_4(t, etx, HME_ETXI_RSIZE, _HME_NDESC / 16 - 1);


	/* step 10. ERX Configuration */
	v = bus_space_read_4(t, erx, HME_ERXI_CFG);

	/* Encode Receive Descriptor ring size: four possible values */
	switch (_HME_NDESC /*XXX*/) {
	case 32:
		v |= HME_ERX_CFG_RINGSIZE32;
		break;
	case 64:
		v |= HME_ERX_CFG_RINGSIZE64;
		break;
	case 128:
		v |= HME_ERX_CFG_RINGSIZE128;
		break;
	case 256:
		v |= HME_ERX_CFG_RINGSIZE256;
		break;
	default:
		printf("hme: invalid Receive Descriptor ring size\n");
		break;
	}

	/* Enable DMA */
	v |= HME_ERX_CFG_DMAENABLE;
	bus_space_write_4(t, erx, HME_ERXI_CFG, v);

	/* step 11. XIF Configuration */
	v = bus_space_read_4(t, mac, HME_MACI_XIF);
	v |= HME_MAC_XIF_OE;
	/* If an external transceiver is connected, enable its MII drivers */
	if ((bus_space_read_4(t, mif, HME_MIFI_CFG) & HME_MIF_CFG_MDI1) != 0)
		v |= HME_MAC_XIF_MIIENABLE;
	bus_space_write_4(t, mac, HME_MACI_XIF, v);


	/* step 12. RX_MAC Configuration Register */
	v = bus_space_read_4(t, mac, HME_MACI_RXCFG);
	v |= HME_MAC_RXCFG_ENABLE;
	bus_space_write_4(t, mac, HME_MACI_RXCFG, v);

	/* step 13. TX_MAC Configuration Register */
	v = bus_space_read_4(t, mac, HME_MACI_TXCFG);
	v |= (HME_MAC_TXCFG_ENABLE | HME_MAC_TXCFG_DGIVEUP);
	bus_space_write_4(t, mac, HME_MACI_TXCFG, v);

	/* step 14. Issue Transmit Pending command */

	/* Call MI initialization function if any */
	if (sc->sc_hwinit)
		(*sc->sc_hwinit)(sc);

	ifp->if_flags |= IFF_RUNNING;
	ifp->if_flags &= ~IFF_OACTIVE;
	ifp->if_timer = 0;
	hme_start(ifp);
}

/*
 * Compare two Ether/802 addresses for equality, inlined and unrolled for
 * speed.
 */
static __inline__ int
ether_cmp(a, b)
	u_char *a, *b;
{

	if (a[5] != b[5] || a[4] != b[4] || a[3] != b[3] ||
	    a[2] != b[2] || a[1] != b[1] || a[0] != b[0])
		return (0);
	return (1);
}


/*
 * Routine to copy from mbuf chain to transmit buffer in
 * network buffer memory.
 * Returns the amount of data copied.
 */
int
hme_put(sc, ri, m)
	struct hme_softc *sc;
	int ri;			/* Ring index */
	struct mbuf *m;
{
	struct mbuf *n;
	int len, tlen = 0;
	caddr_t bp;

	bp = sc->sc_rb.rb_txbuf + (ri % sc->sc_rb.rb_ntbuf) * _HME_BUFSZ;
	for (; m; m = n) {
		len = m->m_len;
		if (len == 0) {
			MFREE(m, n);
			continue;
		}
		bcopy(mtod(m, caddr_t), bp, len);
		bp += len;
		tlen += len;
		MFREE(m, n);
	}
	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 *
hme_get(sc, ri, totlen)
	struct hme_softc *sc;
	int ri, totlen;
{
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	struct mbuf *m, *m0, *newm;
	caddr_t bp;
	int len;

	MGETHDR(m0, M_DONTWAIT, MT_DATA);
	if (m0 == 0)
		return (0);
	m0->m_pkthdr.rcvif = ifp;
	m0->m_pkthdr.len = totlen;
	len = MHLEN;
	m = m0;

	bp = sc->sc_rb.rb_rxbuf + (ri % sc->sc_rb.rb_nrbuf) * _HME_BUFSZ;

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

		if (m == m0) {
			caddr_t newdata = (caddr_t)
			    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 = min(totlen, len);
		bcopy(bp, mtod(m, caddr_t), len);
		bp += len;

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

	return (m0);

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

/*
 * Pass a packet to the higher levels.
 */
void
hme_read(sc, ix, len)
	struct hme_softc *sc;
	int ix, len;
{
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	struct mbuf *m;

	if (len <= sizeof(struct ether_header) ||
	    len > ETHERMTU + sizeof(struct ether_header)) {
#ifdef HMEDEBUG
		printf("%s: invalid packet size %d; dropping\n",
		    sc->sc_dev.dv_xname, len);
#endif
		ifp->if_ierrors++;
		return;
	}

	/* Pull packet off interface. */
	m = hme_get(sc, ix, len);
	if (m == 0) {
		ifp->if_ierrors++;
		return;
	}

	ifp->if_ipackets++;

#if NBPFILTER > 0
	/*
	 * Check if there's a BPF listener on this interface.
	 * If so, hand off the raw packet to BPF.
	 */
	if (ifp->if_bpf) {
		struct ether_header *eh;

		bpf_mtap(ifp->if_bpf, m);

		/*
		 * Note that the interface cannot be in promiscuous mode if
		 * there are no BPF listeners.  And if we are in promiscuous
		 * mode, we have to check if this packet is really ours.
		 */

		/* We assume that the header fit entirely in one mbuf. */
		eh = mtod(m, struct ether_header *);

		if ((ifp->if_flags & IFF_PROMISC) != 0 &&
		    (eh->ether_dhost[0] & 1) == 0 && /* !mcast and !bcast */
		    ether_cmp(eh->ether_dhost, sc->sc_enaddr) == 0) {
			m_freem(m);
			return;
		}
	}
#endif

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

void
hme_start(ifp)
	struct ifnet *ifp;
{
	struct hme_softc *sc = (struct hme_softc *)ifp->if_softc;
	caddr_t txd = sc->sc_rb.rb_txd;
	struct mbuf *m;
	unsigned int ri, len;
	unsigned int ntbuf = sc->sc_rb.rb_ntbuf;

	if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
		return;

	ri = sc->sc_rb.rb_tdhead;

	for (;;) {
		IF_DEQUEUE(&ifp->if_snd, m);
		if (m == 0)
			break;

#if NBPFILTER > 0
		/*
		 * If BPF is listening on this interface, let it see the
		 * packet before we commit it to the wire.
		 */
		if (ifp->if_bpf)
			bpf_mtap(ifp->if_bpf, m);
#endif

		/*
		 * Copy the mbuf chain into the transmit buffer.
		 */
		len = hme_put(sc, ri, m);

		/*
		 * Initialize transmit registers and start transmission
		 */
		HME_XD_SETFLAGS(txd, ri,
			HME_XD_OWN | HME_XD_SOP | HME_XD_EOP |
			HME_XD_ENCODE_TSIZE(len));

		/*if (sc->sc_rb.rb_td_nbusy <= 0)*/
		bus_space_write_4(sc->sc_bustag, sc->sc_etx, HME_ETXI_PENDING,
				  HME_ETX_TP_DMAWAKEUP);

		if (++ri == ntbuf)
			ri = 0;

		if (++sc->sc_rb.rb_td_nbusy == ntbuf) {
			ifp->if_flags |= IFF_OACTIVE;
			break;
		}
	}

	sc->sc_rb.rb_tdhead = ri;
}

/*
 * Transmit interrupt.
 */
int
hme_tint(sc)
	struct hme_softc *sc;
{
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	bus_space_tag_t t = sc->sc_bustag;
	bus_space_handle_t mac = sc->sc_mac;
	unsigned int ri, txflags;

	/*
	 * Unload collision counters
	 */
	ifp->if_collisions +=
		bus_space_read_4(t, mac, HME_MACI_NCCNT) +
		bus_space_read_4(t, mac, HME_MACI_FCCNT) +
		bus_space_read_4(t, mac, HME_MACI_EXCNT) +
		bus_space_read_4(t, mac, HME_MACI_LTCNT);

	/*
	 * then clear the hardware counters.
	 */
	bus_space_write_4(t, mac, HME_MACI_NCCNT, 0);
	bus_space_write_4(t, mac, HME_MACI_FCCNT, 0);
	bus_space_write_4(t, mac, HME_MACI_EXCNT, 0);
	bus_space_write_4(t, mac, HME_MACI_LTCNT, 0);

	/* Fetch current position in the transmit ring */
	ri = sc->sc_rb.rb_tdtail;

	for (;;) {
		if (sc->sc_rb.rb_td_nbusy <= 0)
			break;

		txflags = HME_XD_GETFLAGS(sc->sc_rb.rb_txd, ri);

		if (txflags & HME_XD_OWN)
			break;

		ifp->if_flags &= ~IFF_OACTIVE;
		ifp->if_opackets++;

		if (++ri == sc->sc_rb.rb_ntbuf)
			ri = 0;

		--sc->sc_rb.rb_td_nbusy;
	}

	/* Update ring */
	sc->sc_rb.rb_tdtail = ri;

	hme_start(ifp);

	if (sc->sc_rb.rb_td_nbusy == 0)
		ifp->if_timer = 0;

	return (1);
}

/*
 * Receive interrupt.
 */
int
hme_rint(sc)
	struct hme_softc *sc;
{
	caddr_t xdr = sc->sc_rb.rb_rxd;
	unsigned int nrbuf = sc->sc_rb.rb_nrbuf;
	unsigned int ri, len;
	u_int32_t flags;

	ri = sc->sc_rb.rb_rdtail;

	/*
	 * Process all buffers with valid data.
	 */
	for (;;) {
		flags = HME_XD_GETFLAGS(xdr, ri);
		if (flags & HME_XD_OWN)
			break;

		if (flags & HME_XD_OFL) {
			printf("%s: buffer overflow, ri=%d; flags=0x%x\n",
					sc->sc_dev.dv_xname, ri, flags);
		} else {
			len = HME_XD_DECODE_RSIZE(flags);
			hme_read(sc, ri, len);
		}

		/* This buffer can be used by the hardware again */
		HME_XD_SETFLAGS(xdr, ri,
				HME_XD_OWN | HME_XD_ENCODE_RSIZE(_HME_BUFSZ));

		if (++ri == nrbuf)
			ri = 0;
	}

	sc->sc_rb.rb_rdtail = ri;

	return (1);
}

int
hme_eint(sc, status)
	struct hme_softc *sc;
	u_int status;
{
	char bits[128];

	if ((status & HME_SEB_STAT_MIFIRQ) != 0) {
		printf("%s: XXXlink status changed\n", sc->sc_dev.dv_xname);
		return (1);
	}

	printf("%s: status=%s\n", sc->sc_dev.dv_xname,
		bitmask_snprintf(status, HME_SEB_STAT_BITS, bits,sizeof(bits)));
	return (1);
}

int
hme_intr(v)
	void *v;
{
	struct hme_softc *sc = (struct hme_softc *)v;
	bus_space_tag_t t = sc->sc_bustag;
	bus_space_handle_t seb = sc->sc_seb;
	u_int32_t status;
	int r = 0;

	status = bus_space_read_4(t, seb, HME_SEBI_STAT);

	if ((status & HME_SEB_STAT_ALL_ERRORS) != 0)
		r |= hme_eint(sc, status);

	if ((status & (HME_SEB_STAT_TXALL | HME_SEB_STAT_HOSTTOTX)) != 0)
		r |= hme_tint(sc);

	if ((status & HME_SEB_STAT_RXTOHOST) != 0)
		r |= hme_rint(sc);

	return (r);
}


void
hme_watchdog(ifp)
	struct ifnet *ifp;
{
	struct hme_softc *sc = ifp->if_softc;

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

	hme_reset(sc);
}

/*
 * Initialize the MII Management Interface
 */
void
hme_mifinit(sc)
	struct hme_softc *sc;
{
	bus_space_tag_t t = sc->sc_bustag;
	bus_space_handle_t mif = sc->sc_mif;
	u_int32_t v;

	/* Configure the MIF in frame mode */
	v = bus_space_read_4(t, mif, HME_MIFI_CFG);
	v &= ~HME_MIF_CFG_BBMODE;
	bus_space_write_4(t, mif, HME_MIFI_CFG, v);
}

/*
 * MII interface
 */
static int
hme_mii_readreg(self, phy, reg)
	struct device *self;
	int phy, reg;
{
	struct hme_softc *sc = (void *)self;
	bus_space_tag_t t = sc->sc_bustag;
	bus_space_handle_t mif = sc->sc_mif;
	int n;
	u_int32_t v;

	/* Construct the frame command */
	v = (MII_COMMAND_START << HME_MIF_FO_ST_SHIFT) |
	    HME_MIF_FO_TAMSB |
	    (MII_COMMAND_READ << HME_MIF_FO_OPC_SHIFT) |
	    (phy << HME_MIF_FO_PHYAD_SHIFT) |
	    (reg << HME_MIF_FO_REGAD_SHIFT);

	bus_space_write_4(t, mif, HME_MIFI_FO, v);
	for (n = 0; n < 100; n++) {
		DELAY(1);
		v = bus_space_read_4(t, mif, HME_MIFI_FO);
		if (v & HME_MIF_FO_TALSB)
			return (v & HME_MIF_FO_DATA);
	}

	printf("%s: mii_read timeout\n", sc->sc_dev.dv_xname);
	return (0);
}

static void
hme_mii_writereg(self, phy, reg, val)
	struct device *self;
	int phy, reg, val;
{
	struct hme_softc *sc = (void *)self;
	bus_space_tag_t t = sc->sc_bustag;
	bus_space_handle_t mif = sc->sc_mif;
	int n;
	u_int32_t v;

	/* Construct the frame command */
	v = (MII_COMMAND_START << HME_MIF_FO_ST_SHIFT)	|
	    HME_MIF_FO_TAMSB				|
	    (MII_COMMAND_WRITE << HME_MIF_FO_OPC_SHIFT)	|
	    (phy << HME_MIF_FO_PHYAD_SHIFT)		|
	    (reg << HME_MIF_FO_REGAD_SHIFT)		|
	    (val & HME_MIF_FO_DATA);

	bus_space_write_4(t, mif, HME_MIFI_FO, v);
	for (n = 0; n < 100; n++) {
		DELAY(1);
		v = bus_space_read_4(t, mif, HME_MIFI_FO);
		if (v & HME_MIF_FO_TALSB)
			return;
	}

	printf("%s: mii_write timeout\n", sc->sc_dev.dv_xname);
}

static void
hme_mii_statchg(dev)
	struct device *dev;
{
#ifdef HMEDEBUG
	struct hme_softc *sc = (void *)dev;
	if (sc->sc_debug)
		printf("hme_mii_statchg: status change\n");
#endif
}

int
hme_mediachange(ifp)
	struct ifnet *ifp;
{
	struct hme_softc *sc = ifp->if_softc;
	struct ifmedia *ifm = &sc->sc_media;
	int newmedia = ifm->ifm_media;
	bus_space_tag_t t = sc->sc_bustag;
	bus_space_handle_t mac = sc->sc_mac;
	u_int32_t v;
	int error;

	if (IFM_TYPE(newmedia) != IFM_ETHER)
		return (EINVAL);

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

	if ((error = mii_mediachg(&sc->sc_mii)) != 0)
		return (error);

	v = bus_space_read_4(t, mac, HME_MACI_TXCFG);
	if ((IFM_OPTIONS(sc->sc_mii.mii_media_active) & IFM_FDX) != 0)
		v |= HME_MAC_TXCFG_FULLDPLX;
	else
		v &= ~HME_MAC_TXCFG_FULLDPLX;
	bus_space_write_4(t, mac, HME_MACI_TXCFG, v);

	return (0);
}

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

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

	mii_pollstat(&sc->sc_mii);
	ifmr->ifm_active = sc->sc_mii.mii_media_active;
	ifmr->ifm_status = sc->sc_mii.mii_media_status;
}

/*
 * Process an ioctl request.
 */
int
hme_ioctl(ifp, cmd, data)
	struct ifnet *ifp;
	u_long cmd;
	caddr_t data;
{
	struct hme_softc *sc = ifp->if_softc;
	struct ifaddr *ifa = (struct ifaddr *)data;
	struct ifreq *ifr = (struct ifreq *)data;
	int s, error = 0;

	s = splnet();

	switch (cmd) {

	case SIOCSIFADDR:
		ifp->if_flags |= IFF_UP;

		switch (ifa->ifa_addr->sa_family) {
#ifdef INET
		case AF_INET:
			hme_init(sc);
			arp_ifinit(ifp, ifa);
			break;
#endif
#ifdef NS
		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(ina->x_host.c_host,
				    LLADDR(ifp->if_sadl),
				    sizeof(sc->sc_enaddr));
			}
			/* Set new address. */
			hme_init(sc);
			break;
		    }
#endif
		default:
			hme_init(sc);
			break;
		}
		break;

	case SIOCSIFFLAGS:
		if ((ifp->if_flags & IFF_UP) == 0 &&
		    (ifp->if_flags & IFF_RUNNING) != 0) {
			/*
			 * If interface is marked down and it is running, then
			 * stop it.
			 */
			hme_stop(sc);
			ifp->if_flags &= ~IFF_RUNNING;
		} else if ((ifp->if_flags & IFF_UP) != 0 &&
		    	   (ifp->if_flags & IFF_RUNNING) == 0) {
			/*
			 * If interface is marked up and it is stopped, then
			 * start it.
			 */
			hme_init(sc);
		} else if ((ifp->if_flags & IFF_UP) != 0) {
			/*
			 * Reset the interface to pick up changes in any other
			 * flags that affect hardware registers.
			 */
			/*hme_stop(sc);*/
			hme_init(sc);
		}
#ifdef HMEDEBUG
		sc->sc_debug = (ifp->if_flags & IFF_DEBUG) != 0 ? 1 : 0;
#endif
		break;

	case SIOCADDMULTI:
	case SIOCDELMULTI:
		error = (cmd == SIOCADDMULTI) ?
		    ether_addmulti(ifr, &sc->sc_ethercom) :
		    ether_delmulti(ifr, &sc->sc_ethercom);

		if (error == ENETRESET) {
			/*
			 * Multicast list has changed; set the hardware filter
			 * accordingly.
			 */
			hme_setladrf(sc);
			error = 0;
		}
		break;

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

	default:
		error = EINVAL;
		break;
	}

	splx(s);
	return (error);
}

void
hme_shutdown(arg)
	void *arg;
{

	hme_stop((struct hme_softc *)arg);
}

/*
 * Set up the logical address filter.
 */
void
hme_setladrf(sc)
	struct hme_softc *sc;
{
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	struct ether_multi *enm;
	struct ether_multistep step;
	struct ethercom *ec = &sc->sc_ethercom;
	bus_space_tag_t t = sc->sc_bustag;
	bus_space_handle_t mac = sc->sc_mac;
	u_char *cp;
	u_int32_t crc;
	u_int32_t hash[4];
	int len;

	/*
	 * 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) != 0) {
		u_int32_t v = bus_space_read_4(t, mac, HME_MACI_RXCFG);
		v |= HME_MAC_RXCFG_PMISC;
		bus_space_write_4(t, mac, HME_MACI_RXCFG, v);
		goto allmulti;
	}

	/* Clear hash table */
	hash[3] = hash[2] = hash[1] = hash[0] = 0;
	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.)
			 */
			goto allmulti;
		}

		cp = enm->enm_addrlo;
		crc = 0xffffffff;
		for (len = sizeof(enm->enm_addrlo); --len >= 0;) {
			int octet = *cp++;
			int i;

#define MC_POLY_LE	0xedb88320UL	/* mcast crc, little endian */
			for (i = 0; i < 8; i++) {
				if ((crc & 1) ^ (octet & 1)) {
					crc >>= 1;
					crc ^= MC_POLY_LE;
				} else {
					crc >>= 1;
				}
				octet >>= 1;
			}
		}
		/* Just want the 6 most significant bits. */
		crc >>= 26;

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

		ETHER_NEXT_MULTI(step, enm);
	}

	/* Now load the hash table onto the chip */
	bus_space_write_4(t, mac, HME_MACI_HASHTAB0, hash[0]);
	bus_space_write_4(t, mac, HME_MACI_HASHTAB1, hash[1]);
	bus_space_write_4(t, mac, HME_MACI_HASHTAB2, hash[2]);
	bus_space_write_4(t, mac, HME_MACI_HASHTAB3, hash[3]);

	ifp->if_flags &= ~IFF_ALLMULTI;
	return;

allmulti:
	ifp->if_flags |= IFF_ALLMULTI;
	bus_space_write_4(t, mac, HME_MACI_HASHTAB0, 0xffff);
	bus_space_write_4(t, mac, HME_MACI_HASHTAB1, 0xffff);
	bus_space_write_4(t, mac, HME_MACI_HASHTAB2, 0xffff);
	bus_space_write_4(t, mac, HME_MACI_HASHTAB3, 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).
 */

#if 0
/*
 * contig: contiguous data with no padding.
 *
 * Buffers may have any alignment.
 */

void
hme_copytobuf_contig(sc, from, ri, len)
	struct hme_softc *sc;
	void *from;
	int ri, len;
{
	volatile caddr_t buf = sc->sc_rb.rb_txbuf + (ri * _HME_BUFSZ);

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

void
hme_copyfrombuf_contig(sc, to, boff, len)
	struct hme_softc *sc;
	void *to;
	int boff, len;
{
	volatile caddr_t buf = sc->sc_rb.rb_rxbuf + (ri * _HME_BUFSZ);

	/*
	 * Just call bcopy() to do the work.
	 */
	bcopy(buf, to, len);
}
#endif