xref: /src/sys/arch/mac68k/dev/if_sn.c

/*	$NetBSD: if_sn.c,v 1.1 1997/03/15 20:26:35 briggs Exp $	*/

/*
 * National Semiconductor  SONIC Driver
 * Copyright (c) 1991   Algorithmics Ltd (http://www.algor.co.uk)
 * You may use, copy, and modify this program so long as you retain the
 * copyright line.
 *
 * This driver has been substantially modified since Algorithmics donated
 * it.
 */

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

#include <net/if.h>
#include <net/netisr.h>
#include <net/route.h>

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

#include <vm/vm.h>

extern int kvtop(caddr_t addr);

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

typedef unsigned char uchar;

#include <machine/bus.h>
#include <machine/cpu.h>
#include <machine/viareg.h>
#include <mac68k/dev/if_snreg.h>
#include <mac68k/dev/if_snvar.h>

#include	"nubus.h"

/*
 * Register access macros:
 * SWR is "Sonic Write Register"
 * SRD is "Sonic Read Register"
 */
#define SWR(a, x) 	(a) = (x)
#define SRD(a)		((a) & 0xffff)

#define wbflush()

static void snwatchdog __P((struct ifnet *));
static int sninit __P((struct sn_softc *sc));
static int snstop __P((struct sn_softc *sc));
static int sonicput __P((struct sn_softc *sc, struct mbuf *m0));
static void snintr __P((void *, int));
static int snioctl __P((struct ifnet *ifp, u_long cmd, caddr_t data));
static void snstart __P((struct ifnet *ifp));
static void snreset __P((struct sn_softc *sc));

void camdump __P((struct sn_softc *sc));

struct cfdriver sn_cd = {
	NULL, "sn", DV_IFNET
};

#undef assert
#undef _assert

#ifdef NDEBUG
#define	assert(e)	((void)0)
#define	_assert(e)	((void)0)
#else
#define	_assert(e)	assert(e)
#ifdef __STDC__
#define	assert(e)	((e) ? (void)0 : __assert("sn ", __FILE__, __LINE__, #e))
#else	/* PCC */
#define	assert(e)	((e) ? (void)0 : __assert("sn "__FILE__, __LINE__, "e"))
#endif
#endif

int ethdebug = 0;

/*
 * SONIC buffers need to be aligned 16 or 32 bit aligned.
 * These macros calculate and verify alignment.
 */
#define	ROUNDUP(p, N)	(((int) p + N - 1) & ~(N - 1))

#define SOALIGN(m, array)	(m ? (ROUNDUP(array, 4)) : (ROUNDUP(array, 2)))

#define LOWER(x) ((unsigned)(x) & 0xffff)
#define UPPER(x) ((unsigned)(x) >> 16)

/*
 * Interface exists: make available by filling in network interface
 * record.  System will initialize the interface when it is ready
 * to accept packets.
 */
void
snsetup(sc)
	struct sn_softc	*sc;
{
	struct ifnet	*ifp = &sc->sc_if;
	unsigned char	*p;
	unsigned char	*pp;
	int		i;

	sc->sc_csr = (struct sonic_reg *) sc->sc_regh;

/*
 * Disable caching on register and DMA space.
 */
	physaccess((caddr_t) sc->sc_csr, (caddr_t) kvtop((caddr_t) sc->sc_csr),
		SN_REGSIZE, PG_V | PG_RW | PG_CI);

	physaccess((caddr_t) sc->space, (caddr_t) kvtop((caddr_t) sc->space),
		sizeof(sc->space), PG_V | PG_RW | PG_CI);

/*
 * Put the pup in reset mode (sninit() will fix it later)
 * and clear any interrupts.
 */
	sc->sc_csr->s_cr = CR_RST;
	wbflush();
	sc->sc_csr->s_isr = 0x7fff;
	wbflush();

/*
 * because the SONIC is basically 16bit device it 'concatenates'
 * a higher buffer address to a 16 bit offset--this will cause wrap
 * around problems near the end of 64k !!
 */
	p = &sc->space[0];
	pp = (unsigned char *)ROUNDUP ((int)p, NBPG);
	p = pp;

	for (i = 0; i < NRRA; i++) {
		sc->p_rra[i] = (void *)p;
		sc->v_rra[i] = kvtop(p);
		p += RXRSRC_SIZE(sc);
	}
	sc->v_rea = kvtop(p);

	p = (unsigned char *)SOALIGN(sc, p);

	sc->p_cda = (void *) (p);
	sc->v_cda = kvtop(p);
	p += CDA_SIZE(sc);

	p = (unsigned char *)SOALIGN(sc, p);

	for (i = 0; i < NRDA; i++) {
		sc->p_rda[i] = (void *) p;
		sc->v_rda[i] = kvtop(p);
		p += RXPKT_SIZE(sc);
	}

	p = (unsigned char *)SOALIGN(sc, p);

	for (i = 0; i < NTDA; i++) {
		struct mtd *mtdp = &sc->mtda[i];
		mtdp->mtd_txp = (void *)p;
		mtdp->mtd_vtxp = kvtop(p);
		p += TXP_SIZE(sc);
	}

	p = (unsigned char *)SOALIGN(sc, p);

	if ((p - pp) > NBPG) {
		printf ("sn: sizeof RRA (%ld) + CDA (%ld) +"
			"RDA (%ld) + TDA (%ld) > NBPG (%d). Punt!\n",
			(ulong)sc->p_cda - (ulong)sc->p_rra[0],
			(ulong)sc->p_rda[0] - (ulong)sc->p_cda,
			(ulong)sc->mtda[0].mtd_txp - (ulong)sc->p_rda[0],
			(ulong)p - (ulong)sc->mtda[0].mtd_txp,
			NBPG);
		return;
	}

	p = pp + NBPG;

	for (i = 0; i < NRBA; i+=2) {
		sc->rbuf[i] = (caddr_t) p;
		sc->rbuf[i+1] = (caddr_t)(p + (NBPG/2));
		p += NBPG;
	}

	for (i = 0; i < NTXB; i+=2) {
		sc->tbuf[i] = (caddr_t) p;
		sc->tbuf[i+1] = (caddr_t)(p + (NBPG/2));
		sc->vtbuf[i] = kvtop(sc->tbuf[i]);
		sc->vtbuf[i+1] = kvtop(sc->tbuf[i+1]);
		p += NBPG;
	}

#if 0
	camdump(sc);
#endif
	printf(" address %s\n", ether_sprintf(sc->sc_enaddr));

#if 0
printf("sonic buffers: rra=%p cda=0x%x rda=0x%x tda=0x%x\n",
	sc->p_rra[0], sc->p_cda, sc->p_rda[0], sc->mtda[0].mtd_txp);
#endif

	bcopy(sc->sc_dev.dv_xname, ifp->if_xname, IFNAMSIZ);
	ifp->if_softc = sc;
	ifp->if_ioctl = snioctl;
	ifp->if_start = snstart;
	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
	ifp->if_watchdog = snwatchdog;
#if NBPFILTER > 0
	bpfattach(&ifp->if_bpf, ifp, DLT_EN10MB, sizeof(struct ether_header));
#endif
	if_attach(ifp);
	ether_ifattach(ifp);

	add_nubus_intr(sc->slotno, snintr, (void *) sc);
}

static int
snioctl(ifp, cmd, data)
	struct ifnet *ifp;
	u_long cmd;
	caddr_t data;
{
	struct ifaddr *ifa;
	struct sn_softc *sc = ifp->if_softc;
	int     s = splnet(), err = 0;
	int	temp;

	switch (cmd) {

	case SIOCSIFADDR:
		ifa = (struct ifaddr *)data;
		ifp->if_flags |= IFF_UP;
		switch (ifa->ifa_addr->sa_family) {
#ifdef INET
		case AF_INET:
			(void)sninit(ifp->if_softc);
			arp_ifinit(&sc->sc_arpcom, ifa);
			break;
#endif
		default:
			(void)sninit(ifp->if_softc);
			break;
		}
		break;

	case SIOCSIFFLAGS:
		if ((ifp->if_flags & IFF_UP) == 0 &&
		    ifp->if_flags & IFF_RUNNING) {
			snstop(ifp->if_softc);
			ifp->if_flags &= ~IFF_RUNNING;
		} else if (ifp->if_flags & IFF_UP &&
		    (ifp->if_flags & IFF_RUNNING) == 0)
			(void)sninit(ifp->if_softc);
		/*
		 * If the state of the promiscuous bit changes, the interface
		 * must be reset to effect the change.
		 */
		if (((ifp->if_flags ^ sc->sc_iflags) & IFF_PROMISC) &&
		    (ifp->if_flags & IFF_RUNNING)) {
			sc->sc_iflags = ifp->if_flags;
			printf("change in flags\n");
			temp = sc->sc_if.if_flags & IFF_UP;
			snreset(sc);
			sc->sc_if.if_flags |= temp;
			snstart(ifp);
		}
		break;

	case SIOCADDMULTI:
	case SIOCDELMULTI:
		if(cmd == SIOCADDMULTI)
			err = ether_addmulti((struct ifreq *)data,
						&sc->sc_arpcom);
		else
			err = ether_delmulti((struct ifreq *)data,
						&sc->sc_arpcom);

		if (err == ENETRESET) {
			/*
			 * Multicast list has changed; set the hardware
			 * filter accordingly. But remember UP flag!
			 */
			temp = sc->sc_if.if_flags & IFF_UP;
			snreset(sc);
			sc->sc_if.if_flags |= temp;
			err = 0;
		}
		break;
	default:
		err = EINVAL;
	}
	splx(s);
	return (err);
}

/*
 * Encapsulate a packet of type family for the local net.
 * Use trailer local net encapsulation if enough data in first
 * packet leaves a multiple of 512 bytes of data in remainder.
 */
static void
snstart(ifp)
	struct ifnet *ifp;
{
	struct sn_softc *sc = ifp->if_softc;
	struct mbuf *m;
	int	len;

	if ((sc->sc_if.if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
		return;

outloop:
	/* Check for room in the xmit buffer. */
	if (sc->txb_inuse == sc->txb_cnt) {
		ifp->if_flags |= IFF_OACTIVE;
		return;
	}

	if (sc->sc_csr->s_cr & CR_TXP) {
		return;
	}

	IF_DEQUEUE(&sc->sc_if.if_snd, m);
	if (m == 0)
		return;

	/* We need the header for m_pkthdr.len. */
	if ((m->m_flags & M_PKTHDR) == 0)
		panic("snstart: no header mbuf");

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

	/*
	 * If there is nothing in the o/p queue, and there is room in
	 * the Tx ring, then send the packet directly.  Otherwise append
	 * it to the o/p queue.
	 */
	len = sonicput(sc, m);
#if 0
	if (len != m->m_pkthdr.len) {
		printf("snstart: len %d != m->m_pkthdr.len %d.\n",
			len, m->m_pkthdr.len);
	}
#endif
	len = m->m_pkthdr.len;

	m_freem(m);

	/* Point to next buffer slot and wrap if necessary. */
	if (++sc->txb_new == sc->txb_cnt)
		sc->txb_new = 0;

	sc->txb_inuse++;

	sc->sc_if.if_opackets++;	/* # of pkts */
	sc->sc_sum.ls_opacks++;		/* # of pkts */

	/* Jump back for possibly more punishment. */
	goto outloop;
}

/*
 * This is called from sonicioctl() when /etc/ifconfig is run to set
 * the address or switch the i/f on.
 */
void caminitialise __P((struct sn_softc *));
void camentry __P((struct sn_softc *, int, unsigned char *ea));
void camprogram __P((struct sn_softc *));
void initialise_tda __P((struct sn_softc *));
void initialise_rda __P((struct sn_softc *));
void initialise_rra __P((struct sn_softc *));
void initialise_tba __P((struct sn_softc *));

/*
 * reset and restart the SONIC.  Called in case of fatal
 * hardware/software errors.
 */
static void
snreset(sc)
	struct sn_softc *sc;
{
	printf("snreset\n");
	snstop(sc);
	sninit(sc);
}

static int
sninit(sc)
	struct sn_softc *sc;
{
	struct sonic_reg *csr = sc->sc_csr;
	int s;

	if (sc->sc_if.if_flags & IFF_RUNNING)
		/* already running */
		return (0);

	s = splnet();

	csr->s_cr = CR_RST;	/* s_dcr only accessable reset mode! */

	/* config it */
	csr->s_dcr = sc->s_dcr | (sc->bitmode ? DCR_DW32 : DCR_DW16);
	csr->s_rcr = RCR_BRD | RCR_LBNONE;
	csr->s_imr = IMR_PRXEN | IMR_PTXEN | IMR_TXEREN | IMR_LCDEN;

	/* clear pending interrupts */
	csr->s_isr = 0x7fff;

	/* clear tally counters */
	csr->s_crct = -1;
	csr->s_faet = -1;
	csr->s_mpt = -1;

	initialise_tda(sc);
	initialise_rda(sc);
	initialise_rra(sc);
	initialise_tba(sc);

	/* enable the chip */
	csr->s_cr = 0;
	wbflush();

	/* program the CAM with our address */
	caminitialise(sc);
	camentry(sc, 0, sc->sc_enaddr);
	camprogram(sc);

	/* get it to read resource descriptors */
	csr->s_cr = CR_RRRA;
	wbflush();
	while (csr->s_cr & CR_RRRA)
		continue;

	/* enable rx */
	csr->s_cr = CR_RXEN;
	wbflush();

	/* flag interface as "running" */
	sc->sc_if.if_flags |= IFF_RUNNING;

	splx(s);
	return (0);
}

/*
 * close down an interface and free its buffers
 * Called on final close of device, or if sninit() fails
 * part way through.
 */
static int
snstop(sc)
	struct sn_softc *sc;
{
	struct mtd *mtd;
	int s = splnet();

	/* stick chip in reset */
	sc->sc_csr->s_cr = CR_RST;
	wbflush();

	/* free all receive buffers (currently static so nothing to do) */

	/* free all pending transmit mbufs */
	while (sc->mtd_hw != sc->mtd_free) {
		mtd = &sc->mtda[sc->mtd_hw];
		mtd->mtd_buf = 0;
		if (++sc->mtd_hw == NTDA) sc->mtd_hw = 0;
	}
	sc->txb_inuse = 0;

	sc->sc_if.if_timer = 0;
	sc->sc_if.if_flags &= ~(IFF_RUNNING | IFF_UP);

	splx(s);
	return (0);
}

/*
 * Called if any Tx packets remain unsent after 5 seconds,
 * In all cases we just reset the chip, and any retransmission
 * will be handled by higher level protocol timeouts.
 */
static void
snwatchdog(ifp)
	struct ifnet *ifp;
{
	struct sn_softc *sc = ifp->if_softc;
	struct mtd	*mtd;
	int		temp;

	if (sc->mtd_hw != sc->mtd_free) {
		/* something still pending for transmit */
		mtd = &sc->mtda[sc->mtd_hw];
		if (SRO(sc->bitmode, mtd->mtd_txp, TXP_STATUS) == 0)
			log(LOG_ERR, "%s: Tx - timeout\n",
				sc->sc_dev.dv_xname);
		else
			log(LOG_ERR, "%s: Tx - lost interrupt\n",
			   	 sc->sc_dev.dv_xname);
		temp = sc->sc_if.if_flags & IFF_UP;
		snreset(sc);
		sc->sc_if.if_flags |= temp;
	}
}

/*
 * stuff packet into sonic (at splnet)
 */
static int
sonicput(sc, m0)
	struct sn_softc *sc;
	struct mbuf *m0;
{
	struct sonic_reg	*csr = sc->sc_csr;
	unsigned char		*buff, *buffer;
	void			*txp;
	struct mtd		*mtdp;
	struct mbuf		*m;
	unsigned int		len = 0;
	unsigned int		totlen = 0;
	int			mtd_free = sc->mtd_free;
	int			mtd_next;
	int			txb_new = sc->txb_new;

	/* grab the replacement mtd */
	mtdp = &sc->mtda[mtd_free];

	if ((mtd_next = mtd_free + 1) == NTDA)
		mtd_next = 0;

	if (mtd_next == sc->mtd_hw) {
		return (0);
	}

	/* We are guaranteed, if we get here, that the xmit buffer is free. */
	buff = buffer = sc->tbuf[txb_new];

	/* this packet goes to mtdnext fill in the TDA */
	mtdp->mtd_buf = buffer;
	txp = mtdp->mtd_txp;
	SWO(sc->bitmode, txp, TXP_CONFIG, 0);

	for (m = m0; m; m = m->m_next) {
		unsigned char *data = mtod(m, u_char *);
		len = m->m_len;
		totlen += len;
		bcopy(data, buff, len);
		buff += len;
	}
	if (totlen >= TXBSIZE) {
		panic("packet overflow in sonicput.");
	}
	SWO(sc->bitmode, txp, TXP_FRAGOFF+(0*TXP_FRAGSIZE)+TXP_FPTRLO,
		LOWER(sc->vtbuf[txb_new]));
	SWO(sc->bitmode, txp, TXP_FRAGOFF+(0*TXP_FRAGSIZE)+TXP_FPTRHI,
		UPPER(sc->vtbuf[txb_new]));

	if (totlen < ETHERMIN + sizeof(struct ether_header)) {
		int pad = ETHERMIN + sizeof(struct ether_header) - totlen;
		bzero(buffer + totlen, pad);
		totlen = ETHERMIN + sizeof(struct ether_header);
	}

	SWO(sc->bitmode, txp, TXP_FRAGOFF+(0*TXP_FRAGSIZE)+TXP_FSIZE,
		totlen);
	SWO(sc->bitmode, txp, TXP_FRAGCNT, 1);
	SWO(sc->bitmode, txp, TXP_PKTSIZE, totlen);

	/* link onto the next mtd that will be used */
	SWO(sc->bitmode, txp, TXP_FRAGOFF+(1*TXP_FRAGSIZE)+TXP_FPTRLO,
		LOWER(sc->mtda[mtd_next].mtd_vtxp) | EOL);

	/*
	 * The previous txp.tlink currently contains a pointer to
	 * our txp | EOL. Want to clear the EOL, so write our
	 * pointer to the previous txp.
	 */
	SWO(sc->bitmode, sc->mtda[sc->mtd_prev].mtd_txp, sc->mtd_tlinko,
		LOWER(mtdp->mtd_vtxp));

	sc->mtd_prev = mtd_free;
	sc->mtd_free = mtd_next;

	/* make sure chip is running */
	wbflush();
	csr->s_cr = CR_TXP;
	wbflush();
	sc->sc_if.if_timer = 5;	/* 5 seconds to watch for failing to transmit */

	return (totlen);
}

void sonictxint __P((struct sn_softc *));
void sonicrxint __P((struct sn_softc *));

int sonic_read __P((struct sn_softc *, caddr_t, int));
struct mbuf *sonic_get __P((struct sn_softc *, struct ether_header *, int));

/*
 * CAM support
 */
void
caminitialise(sc)
	struct sn_softc *sc;
{
	int    	i;
	void	*p_cda = sc->p_cda;
	int	bitmode = sc->bitmode;

	for (i = 0; i < MAXCAM; i++)
		SWO(bitmode, p_cda, (CDA_CAMDESC * i + CDA_CAMEP), i);
	SWO(bitmode, p_cda, CDA_ENABLE, 0);
}

void
camentry(sc, entry, ea)
	int entry;
	unsigned char *ea;
	struct sn_softc *sc;
{
	int	bitmode = sc->bitmode;
	void	*p_cda = sc->p_cda;
	int		camoffset = entry * CDA_CAMDESC;

	SWO(bitmode, p_cda, camoffset + CDA_CAMEP, entry);
	SWO(bitmode, p_cda, camoffset + CDA_CAMAP2, (ea[5] << 8) | ea[4]);
	SWO(bitmode, p_cda, camoffset + CDA_CAMAP1, (ea[3] << 8) | ea[2]);
	SWO(bitmode, p_cda, camoffset + CDA_CAMAP0, (ea[1] << 8) | ea[0]);
	SWO(bitmode, p_cda, CDA_ENABLE, (1 << entry));
}

void
camprogram(sc)
	struct sn_softc *sc;
{
	struct sonic_reg *csr;
	int     timeout;

	csr = sc->sc_csr;
	csr->s_cdp = LOWER(sc->v_cda);
	csr->s_cdc = MAXCAM;
	csr->s_cr = CR_LCAM;
	wbflush();

	timeout = 10000;
	while (csr->s_cr & CR_LCAM && timeout--)
		continue;
	if (timeout == 0) {
		/* XXX */
		panic("sonic: CAM initialisation failed\n");
	}
	timeout = 10000;
	while ((csr->s_isr & ISR_LCD) == 0 && timeout--)
		continue;

	if (csr->s_isr & ISR_LCD)
		csr->s_isr = ISR_LCD;
	else
		printf("sonic: CAM initialisation without interrupt\n");
}

#if 0
void
camdump(sc)
	struct sn_softc *sc;
{
	struct sonic_reg *csr = sc->sc_csr;
	int i;

	printf("CAM entries:\n");
	csr->s_cr = CR_RST;
	wbflush();

	for (i = 0; i < 16; i++) {
		ushort  ap2, ap1, ap0;
		csr->s_cep = i;
		wbflush();
		ap2 = csr->s_cap2;
		ap1 = csr->s_cap1;
		ap0 = csr->s_cap0;
		printf("%d: ap2=0x%x ap1=0x%x ap0=0x%x\n", i, ap2, ap1, ap0);
	}
	printf("CAM enable 0x%lx\n", csr->s_cep);

	csr->s_cr = 0;
	wbflush();
}
#endif

void
initialise_tda(sc)
	struct sn_softc *sc;
{
	struct sonic_reg *csr;
	struct mtd *mtd;
	int     i;

	csr = sc->sc_csr;

	for (i = 0; i < NTDA; i++) {
		mtd = &sc->mtda[i];
		mtd->mtd_buf = 0;
	}

	sc->mtd_hw = 0;
	sc->mtd_prev = NTDA-1;
	sc->mtd_free = 0;
	sc->mtd_tlinko = TXP_FRAGOFF + 1*TXP_FRAGSIZE + TXP_FPTRLO;

	csr->s_utda = UPPER(sc->mtda[0].mtd_vtxp);
	csr->s_ctda = LOWER(sc->mtda[0].mtd_vtxp);
}

void
initialise_rda(sc)
	struct sn_softc *sc;
{
	struct sonic_reg *csr;
	int	bitmode = sc->bitmode;
	int     i;

	csr = sc->sc_csr;

	/* link the RDA's together into a circular list */
	for (i = 0; i < (NRDA - 1); i++) {
		SWO(bitmode, sc->p_rda[i], RXPKT_RLINK, LOWER(sc->v_rda[i+1]));
		SWO(bitmode, sc->p_rda[i], RXPKT_INUSE, 1);
	}
	SWO(bitmode, sc->p_rda[NRDA - 1], RXPKT_RLINK, LOWER(sc->v_rda[0]) | EOL);
	SWO(bitmode, sc->p_rda[NRDA - 1], RXPKT_INUSE, 1);

	/* mark end of receive descriptor list */
	sc->sc_rdamark = NRDA - 1;

	sc->sc_rxmark = 0;

	SWR(csr->s_urda, UPPER(sc->v_rda[0]));
	SWR(csr->s_crda, LOWER(sc->v_rda[0]));
	wbflush();
}

void
initialise_rra(sc)
	struct sn_softc *sc;
{
	struct sonic_reg *csr;
	int     	i;
	unsigned int	v;
	int		bitmode = sc->bitmode;

	csr = sc->sc_csr;

	if (bitmode)
		csr->s_eobc = RBASIZE(sc) / 2 - 2; /* must be >= MAXETHERPKT */
	else
		csr->s_eobc = RBASIZE(sc) / 2 - 1; /* must be >= MAXETHERPKT */
	csr->s_urra = UPPER(sc->v_rra[0]);
	csr->s_rsa = LOWER(sc->v_rra[0]);
	/* rea must point just past the end of the rra space */
	csr->s_rea = LOWER(sc->v_rea);
	csr->s_rrp = LOWER(sc->v_rra[0]);

	/* fill up SOME of the rra with buffers */
	for (i = 0; i < NRBA; i++) {
		v = kvtop(sc->rbuf[i]);
		SWO(bitmode, sc->p_rra[i], RXRSRC_PTRHI, UPPER(v));
		SWO(bitmode, sc->p_rra[i], RXRSRC_PTRLO, LOWER(v));
		SWO(bitmode, sc->p_rra[i], RXRSRC_WCHI, UPPER(RBASIZE(sc) / 2));
		SWO(bitmode, sc->p_rra[i], RXRSRC_WCLO, LOWER(RBASIZE(sc) / 2));
	}
	sc->sc_rramark = NRBA;
	csr->s_rwp = LOWER(sc->v_rra[sc->sc_rramark]);
	wbflush();
}

void
initialise_tba(sc)
	struct sn_softc *sc;
{
	sc->txb_cnt = NTXB;
	sc->txb_inuse = 0;
	sc->txb_new = 0;
}

static void
snintr(arg, slot)
	void	*arg;
	int	slot;
{
	struct sn_softc	*sc = (struct sn_softc *)arg;
	struct sonic_reg *csr = sc->sc_csr;
	int	isr;

	while ((isr = (csr->s_isr & ISR_ALL)) != 0) {
		/* scrub the interrupts that we are going to service */
		csr->s_isr = isr;
		wbflush();

		if (isr & (ISR_BR | ISR_LCD | ISR_PINT | ISR_TC))
			printf("sonic: unexpected interrupt status 0x%x\n", isr);

		if (isr & (ISR_TXDN | ISR_TXER))
			sonictxint(sc);

		if (isr & ISR_PKTRX)
			sonicrxint(sc);

		if (isr & (ISR_HBL | ISR_RDE | ISR_RBE | ISR_RBAE | ISR_RFO)) {
			if (isr & ISR_HBL)
				/*
				 * The repeater is not providing a heartbeat.
				 * In itself this isn't harmful, lots of the
				 * cheap repeater hubs don't supply a heartbeat.
				 * So ignore the lack of heartbeat. Its only
				 * if we can't detect a carrier that we have a
				 * problem.
				 */
			if (isr & ISR_RDE)
				printf("sonic: receive descriptors exhausted\n");
			if (isr & ISR_RBE)
				printf("sonic: receive buffers exhausted\n");
			if (isr & ISR_RBAE)
				printf("sonic: receive buffer area exhausted\n");
			if (isr & ISR_RFO)
				printf("sonic: receive FIFO overrun\n");
		}
		if (isr & (ISR_CRC | ISR_FAE | ISR_MP)) {
#ifdef notdef
			if (isr & ISR_CRC)
				sc->sc_crctally++;
			if (isr & ISR_FAE)
				sc->sc_faetally++;
			if (isr & ISR_MP)
				sc->sc_mptally++;
#endif
		}
		snstart(&sc->sc_if);
	}
	return;
}

/*
 * Transmit interrupt routine
 */
void
sonictxint(sc)
	struct sn_softc *sc;
{
	void		*txp;
	struct sonic_reg *csr;
	struct mtd	*mtd;
	/* XXX DG make mtd_hw a local var */

	if (sc->mtd_hw == sc->mtd_free)
		return;

	csr = sc->sc_csr;

	while (sc->mtd_hw != sc->mtd_free) {
		mtd = &sc->mtda[sc->mtd_hw];
		if (mtd->mtd_buf == 0)
			break;

		txp = mtd->mtd_txp;

		if (SRO(sc->bitmode, txp, TXP_STATUS) == 0)
			return; /* it hasn't really gone yet */

		if (ethdebug) {
			struct ether_header *eh;

			eh = (struct ether_header *) mtd->mtd_buf;
			printf("xmit status=0x%x len=%d type=0x%x from %s",
			    SRO(sc->bitmode, txp, TXP_STATUS),
			    SRO(sc->bitmode, txp, TXP_PKTSIZE),
			    htons(eh->ether_type),
			    ether_sprintf(eh->ether_shost));
			printf(" (to %s)\n", ether_sprintf(eh->ether_dhost));
		}
		sc->txb_inuse--;
		mtd->mtd_buf = 0;
		if (++sc->mtd_hw == NTDA) sc->mtd_hw = 0;

		/* XXX - Do stats here. */

		if ((SRO(sc->bitmode, txp, TXP_STATUS) & TCR_PTX) == 0) {
			printf("sonic: Tx packet status=0x%x\n",
				SRO(sc->bitmode, txp, TXP_STATUS));

			/* XXX - DG This looks bogus */
			if (sc->mtd_hw != sc->mtd_free) {
				printf("resubmitting remaining packets\n");
				mtd = &sc->mtda[sc->mtd_hw];
				csr->s_ctda = LOWER(mtd->mtd_vtxp);
				csr->s_cr = CR_TXP;
				wbflush();
				return;
			}
		}
	}
}

/*
 * Receive interrupt routine
 */
void
sonicrxint(sc)
	struct sn_softc *sc;
{
	struct sonic_reg	*csr = sc->sc_csr;
	void			*rda;
	int     		orra;
	int			len;
	int			rramark;
	int			rdamark;
	int			bitmode = sc->bitmode;
	void			*tmp1;
	void			*tmp2;

	rda = sc->p_rda[sc->sc_rxmark];

	while (SRO(bitmode, rda, RXPKT_INUSE) == 0) {
		unsigned status = SRO(bitmode, rda, RXPKT_STATUS);
		if ((status & RCR_LPKT) == 0)
			printf("sonic: more than one packet in RBA!\n");

		orra = RBASEQ(SRO(bitmode, rda, RXPKT_SEQNO)) & RRAMASK;
		len = SRO(bitmode, rda, RXPKT_BYTEC) -
			sizeof(struct ether_header) - FCSSIZE;
		if (status & RCR_PRX) {
			if (sonic_read(sc, sc->rbuf[orra & RBAMASK], len)) {
				sc->sc_if.if_ipackets++;
				sc->sc_sum.ls_ipacks++;
				sc->sc_missed = 0;
			}
		} else
			sc->sc_if.if_ierrors++;

		/*
		 * give receive buffer area back to chip.
		 *
		 * orra is now empty of packets and can be freed if
		 * sonic read didnt copy it out then we would have to
		 * wait !!
		 * (dont bother add it back in again straight away)
		 *
		 * Really, we're doing p_rra[rramark] = p_rra[orra] but
		 * we have to use the macros because SONIC might be in
		 * 16 or 32 bit mode.
		 */
		rramark = sc->sc_rramark;
		tmp1 = sc->p_rra[rramark];
		tmp2 = sc->p_rra[orra];
		SWO(bitmode, tmp1, RXRSRC_PTRLO,
			SRO(bitmode, tmp2, RXRSRC_PTRLO));
		SWO(bitmode, tmp1, RXRSRC_PTRHI,
			SRO(bitmode, tmp2, RXRSRC_PTRHI));
		SWO(bitmode, tmp1, RXRSRC_WCLO,
			SRO(bitmode, tmp2, RXRSRC_WCLO));
		SWO(bitmode, tmp1, RXRSRC_WCHI,
			SRO(bitmode, tmp2, RXRSRC_WCHI));

		/* zap old rra for fun */
		SWO(bitmode, tmp2, RXRSRC_WCHI, 0);
		SWO(bitmode, tmp2, RXRSRC_WCLO, 0);

		sc->sc_rramark = (++rramark) & RRAMASK;
		csr->s_rwp = LOWER(sc->v_rra[rramark]);
		wbflush();

		/*
		 * give receive descriptor back to chip simple
		 * list is circular
		 */
		rdamark = sc->sc_rdamark;
		SWO(bitmode, rda, RXPKT_INUSE, 1);
		SWO(bitmode, rda, RXPKT_RLINK,
			SRO(bitmode, rda, RXPKT_RLINK) | EOL);
		SWO(bitmode, sc->p_rda[rdamark], RXPKT_RLINK,
			SRO(bitmode, sc->p_rda[rdamark], RXPKT_RLINK) & ~EOL);
		sc->sc_rdamark = sc->sc_rxmark;

		if (++sc->sc_rxmark >= NRDA)
			sc->sc_rxmark = 0;
		rda = sc->p_rda[sc->sc_rxmark];
	}
}

/*
 * sonic_read -- pull packet off interface and forward to
 * appropriate protocol handler
 */
int
sonic_read(sc, pkt, len)
	struct sn_softc *sc;
	caddr_t pkt;
	int len;
{
	struct ifnet *ifp = &sc->sc_if;
	struct ether_header *et;
	struct mbuf *m;

	/*
         * Get pointer to ethernet header (in input buffer).
         * Deal with trailer protocol: if type is PUP trailer
         * get true type from first 16-bit word past data.
         * Remember that type was trailer by setting off.
         */
	et = (struct ether_header *)pkt;

	if (ethdebug) {
		printf("rcvd 0x%p len=%d type=0x%x from %s",
		    et, len, htons(et->ether_type),
		    ether_sprintf(et->ether_shost));
		printf(" (to %s)\n", ether_sprintf(et->ether_dhost));
	}
	if (len < ETHERMIN || len > ETHERMTU) {
		printf("sonic: invalid packet length %d bytes\n", len);
		return (0);
	}

#if NBPFILTER > 0
	/*
	 * Check if there's a bpf filter listening on this interface.
	 * If so, hand off the raw packet to enet, then discard things
	 * not destined for us (but be sure to keep broadcast/multicast).
	 */
	if (sc->sc_if.if_bpf) {
		bpf_tap(sc->sc_if.if_bpf, pkt,
		    len + sizeof(struct ether_header));
		if ((ifp->if_flags & IFF_PROMISC) != 0 &&
		    (et->ether_dhost[0] & 1) == 0 && /* !mcast and !bcast */
		    bcmp(et->ether_dhost, sc->sc_enaddr,
			    sizeof(et->ether_dhost)) != 0)
			return (0);
	}
#endif
	m = sonic_get(sc, et, len);
	if (m == NULL)
		return (0);
	ether_input(ifp, et, m);
	return(1);
}

#define sonicdataaddr(eh, off, type)       ((type)(((caddr_t)((eh)+1)+(off))))

/*
 * munge the received packet into an mbuf chain
 * because we are using stupid buffer management this
 * is slow.
 */
struct mbuf *
sonic_get(sc, eh, datalen)
	struct sn_softc *sc;
	struct ether_header *eh;
	int datalen;
{
	struct mbuf *m;
	struct mbuf *top = 0, **mp = &top;
	int	len;
	char   *spkt = sonicdataaddr(eh, 0, caddr_t);
	char   *epkt = spkt + datalen;
	char *cp = spkt;

	epkt = cp + datalen;
	MGETHDR(m, M_DONTWAIT, MT_DATA);
	if (m == 0)
		return (0);
	m->m_pkthdr.rcvif = &sc->sc_if;
	m->m_pkthdr.len = datalen;
	m->m_len = MHLEN;

	while (datalen > 0) {
		if (top) {
			MGET(m, M_DONTWAIT, MT_DATA);
			if (m == 0) {
				m_freem(top);
				return (0);
			}
			m->m_len = MLEN;
		}
		len = min(datalen, epkt - cp);
		if (len >= MINCLSIZE) {
			MCLGET(m, M_DONTWAIT);
			if (m->m_flags & M_EXT)
				m->m_len = len = min(len, MCLBYTES);
			else
				len = m->m_len;
		} else {
			/*
		         * Place initial small packet/header at end of mbuf.
		         */
			if (len < m->m_len) {
				if (top == 0 && len + max_linkhdr <= m->m_len)
					m->m_data += max_linkhdr;
				m->m_len = len;
			} else
				len = m->m_len;
		}
		bcopy(cp, mtod(m, caddr_t), (unsigned) len);
		cp += len;
		*mp = m;
		mp = &m->m_next;
		datalen -= len;
		if (cp == epkt)
			cp = spkt;
	}
	return (top);
}