/*      $NetBSD: if_sn.c,v 1.56 2024/07/05 04:31:49 rin Exp $   */

/*
 * National Semiconductor  DP8393X 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.
 *
 *   Denton Gentry <denny1@home.com>
 * and also
 *   Yanagisawa Takeshi <yanagisw@aa.ap.titech.ac.jp>
 * did the work to get this running on the Macintosh.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: if_sn.c,v 1.56 2024/07/05 04:31:49 rin Exp $");

#include "opt_inet.h"

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

#include <uvm/uvm_extern.h>

#include <machine/cpu.h>
#include <newsmips/apbus/apbusvar.h>
#include <newsmips/apbus/if_snreg.h>
#include <newsmips/apbus/if_snvar.h>

/* #define SNDEBUG */

#ifdef SNDEBUG
# define DPRINTF printf
#else
# define DPRINTF while (0) printf
#endif

static void     snwatchdog(struct ifnet *);
static int      sninit(struct sn_softc *sc);
static int      snstop(struct sn_softc *sc);
static int      snioctl(struct ifnet *ifp, u_long cmd, void *data);
static void     snstart(struct ifnet *ifp);
static void     snreset(struct sn_softc *sc);

static void     caminitialise(struct sn_softc *);
static void     camentry(struct sn_softc *, int, const u_char *ea);
static void     camprogram(struct sn_softc *);
static void     initialise_tda(struct sn_softc *);
static void     initialise_rda(struct sn_softc *);
static void     initialise_rra(struct sn_softc *);
#ifdef SNDEBUG
static void     camdump(struct sn_softc *sc);
#endif

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

static inline u_int     sonicput(struct sn_softc *sc, struct mbuf *m0,
    int mtd_next);
static inline int       sonic_read(struct sn_softc *, void *, int);
static inline struct mbuf *sonic_get(struct sn_softc *, void *, int);

/*
 * SONIC buffers need to be aligned 16 or 32 bit aligned.
 * These macros calculate and verify alignment.
 */
#define SOALIGN(m, array)       (m ? (roundup((int)array, 4)) : \
                                     (roundup((int)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.
 */
int
snsetup(struct sn_softc *sc, uint8_t *lladdr)
{
        struct ifnet *ifp = &sc->sc_if;
        uint8_t *p;
        uint8_t *pp;
        int     i;

        if (sc->memory == NULL) {
                aprint_error_dev(sc->sc_dev,
                    "memory allocation for descriptors failed\n");
                return 1;
        }

        /*
         * Put the pup in reset mode (sninit() will fix it later),
         * stop the timer, disable all interrupts and clear any interrupts.
         */
        NIC_PUT(sc, SNR_CR, CR_STP);
        wbflush();
        NIC_PUT(sc, SNR_CR, CR_RST);
        wbflush();
        NIC_PUT(sc, SNR_IMR, 0);
        wbflush();
        NIC_PUT(sc, SNR_ISR, ISR_ALL);
        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->memory;
        pp = (uint8_t *)roundup((int)p, PAGE_SIZE);
        p = pp;

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

        p = (uint8_t *)SOALIGN(sc, p);

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

        p = (uint8_t *)SOALIGN(sc, p);

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

        p = (uint8_t *)SOALIGN(sc, p);

        if ((p - pp) > PAGE_SIZE) {
                aprint_error_dev(sc->sc_dev, "sizeof RRA (%ld) + CDA (%ld) +"
                    "TDA (%ld) > PAGE_SIZE (%d). Punt!\n",
                    (ulong)sc->p_cda - (ulong)sc->p_rra[0],
                    (ulong)sc->mtda[0].mtd_txp - (ulong)sc->p_cda,
                    (ulong)p - (ulong)sc->mtda[0].mtd_txp,
                    PAGE_SIZE);
                return 1;
        }

        p = pp + PAGE_SIZE;
        pp = p;

        sc->sc_nrda = PAGE_SIZE / RXPKT_SIZE(sc);
        sc->p_rda = (void *)p;
        sc->v_rda = SONIC_GETDMA(sc, p);

        p = pp + PAGE_SIZE;

        for (i = 0; i < NRBA; i++) {
                sc->rbuf[i] = SONIC_BUFFER(sc, p);
                p += PAGE_SIZE;
        }

        pp = p;
        for (i = 0; i < NTDA; i++) {
                struct mtd *mtdp = &sc->mtda[i];

                mtdp->mtd_buf = SONIC_BUFFER(sc, p);
                mtdp->mtd_vbuf = SONIC_GETDMA(sc, p);
                p += TXBSIZE;
        }

#ifdef SNDEBUG
        camdump(sc);
#endif
        aprint_normal_dev(sc->sc_dev, "Ethernet address %s\n",
            ether_sprintf(lladdr));

#ifdef SNDEBUG
        aprint_debug_dev(sc->sc_dev, "buffers: rra=%p cda=%p rda=%p tda=%p\n",
            sc->p_rra[0], sc->p_cda,
            sc->p_rda, sc->mtda[0].mtd_txp);
#endif

        strcpy(ifp->if_xname, device_xname(sc->sc_dev));
        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_attach(ifp);
        if_deferred_start_init(ifp, NULL);
        ether_ifattach(ifp, lladdr);

        return 0;
}

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

        switch (cmd) {

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

        case SIOCSIFFLAGS:
                if ((err = ifioctl_common(ifp, cmd, data)) != 0)
                        break;
                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.
                         */
                        snstop(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.
                         */
                        (void)sninit(sc);
                } else {
                        /*
                         * reset the interface to pick up any other changes
                         * in flags
                         */
                        temp = ifp->if_flags & IFF_UP;
                        snreset(sc);
                        ifp->if_flags |= temp;
                        snstart(ifp);
                }
                break;

        case SIOCADDMULTI:
        case SIOCDELMULTI:
                if ((err = ether_ioctl(ifp, cmd, data)) == ENETRESET) {
                        /*
                         * Multicast list has changed; set the hardware
                         * filter accordingly. But remember UP flag!
                         */
                        if (ifp->if_flags & IFF_RUNNING) {
                                temp = ifp->if_flags & IFF_UP;
                                snreset(sc);
                                ifp->if_flags |= temp;
                        }
                        err = 0;
                }
                break;
        default:
                err = ether_ioctl(ifp, cmd, data);
                break;
        }
        splx(s);
        return err;
}

/*
 * Encapsulate a packet of type family for the local net.
 */
static void
snstart(struct ifnet *ifp)
{
        struct sn_softc *sc = ifp->if_softc;
        struct mbuf     *m;
        int             mtd_next;

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

outloop:
        /* Check for room in the xmit buffer. */
        if ((mtd_next = (sc->mtd_free + 1)) == NTDA)
                mtd_next = 0;

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

        IF_POLL(&ifp->if_snd, m);
        if (m == 0)
                return;

        /* We need the header for m_pkthdr.len. */
        KASSERT(m->m_flags & M_PKTHDR);

        /*
         * If bpf is listening on this interface, let it
         * see the packet before we commit it to the wire.
         */
        bpf_mtap(ifp, m, BPF_D_OUT);

        /*
         * If there is nothing in the o/p queue, and there is room in
         * the Tx ring, then send the packet directly.  Otherwise it
         * stays on the queue.
         */
        if ((sonicput(sc, m, mtd_next)) == 0) {
                return;
        }
        IF_DEQUEUE(&ifp->if_snd, m);

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

        if_statinc(ifp, if_opackets);           /* # of pkts */

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

/*
 * reset and restart the SONIC.  Called in case of fatal
 * hardware/software errors.
 */
static void
snreset(struct sn_softc *sc)
{

        snstop(sc);
        sninit(sc);
}

static int
sninit(struct sn_softc *sc)
{
        u_long  s_rcr;
        int     s;

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

        s = splnet();

        NIC_PUT(sc, SNR_CR, CR_RST);    /* DCR only accessible in reset mode! */

        /* config it */
        NIC_PUT(sc, SNR_DCR, (sc->snr_dcr |
                (sc->bitmode ? DCR_DW32 : DCR_DW16)));
        NIC_PUT(sc, SNR_DCR2, sc->snr_dcr2);

        s_rcr = RCR_BRD | RCR_LBNONE;
        if (sc->sc_if.if_flags & IFF_PROMISC)
                s_rcr |= RCR_PRO;
        if (sc->sc_if.if_flags & IFF_ALLMULTI)
                s_rcr |= RCR_AMC;
        NIC_PUT(sc, SNR_RCR, s_rcr);

#if 0
        NIC_PUT(sc, SNR_IMR, (IMR_PRXEN | IMR_PTXEN | IMR_TXEREN | IMR_LCDEN));
#else
        NIC_PUT(sc, SNR_IMR, IMR_PRXEN | IMR_PTXEN | IMR_TXEREN | IMR_LCDEN |
                             IMR_BREN  | IMR_HBLEN | IMR_RDEEN  | IMR_RBEEN |
                             IMR_RBAEEN | IMR_RFOEN);
#endif

        /* clear pending interrupts */
        NIC_PUT(sc, SNR_ISR, ISR_ALL);

        /* clear tally counters */
        NIC_PUT(sc, SNR_CRCT, -1);
        NIC_PUT(sc, SNR_FAET, -1);
        NIC_PUT(sc, SNR_MPT, -1);

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

        sn_md_init(sc);                 /* MD initialization */

        /* enable the chip */
        NIC_PUT(sc, SNR_CR, 0);
        wbflush();

        /* program the CAM */
        camprogram(sc);

        /* get it to read resource descriptors */
        NIC_PUT(sc, SNR_CR, CR_RRRA);
        wbflush();
        while ((NIC_GET(sc, SNR_CR)) & CR_RRRA)
                continue;

        /* enable rx */
        NIC_PUT(sc, SNR_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(struct sn_softc *sc)
{
        struct mtd *mtd;
        int     s = splnet();

        /* stick chip in reset */
        NIC_PUT(sc, SNR_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];
                m_freem(mtd->mtd_mbuf);
                if (++sc->mtd_hw == NTDA) sc->mtd_hw = 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(struct ifnet *ifp)
{
        struct sn_softc *sc = ifp->if_softc;
        struct mtd *mtd;
        u_short 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",
                            device_xname(sc->sc_dev));
                else
                        log(LOG_ERR, "%s: Tx - lost interrupt\n",
                            device_xname(sc->sc_dev));
                temp = ifp->if_flags & IFF_UP;
                snreset(sc);
                ifp->if_flags |= temp;
        }
}

/*
 * stuff packet into sonic (at splnet)
 */
static inline u_int
sonicput(struct sn_softc *sc, struct mbuf *m0, int mtd_next)
{
        struct mtd *mtdp;
        struct mbuf *m;
        u_char  *buff;
        void    *txp;
        u_int   len = 0;
        u_int   totlen = 0;

#ifdef whyonearthwouldyoudothis
        if (NIC_GET(sc, SNR_CR) & CR_TXP)
                return 0;
#endif

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

        buff = mtdp->mtd_buf;

        /* this packet goes to mtdnext fill in the TDA */
        mtdp->mtd_mbuf = m0;
        txp = mtdp->mtd_txp;

        /* Write to the config word. Every (NTDA/2)+1 packets we set an intr */
        if (sc->mtd_pint == 0) {
                sc->mtd_pint = NTDA/2;
                SWO(sc->bitmode, txp, TXP_CONFIG, TCR_PINT);
        } else {
                sc->mtd_pint--;
                SWO(sc->bitmode, txp, TXP_CONFIG, 0);
        }

        for (m = m0; m; m = m->m_next) {
                u_char *data = mtod(m, u_char *);
                len = m->m_len;
                totlen += len;
                memcpy(buff, data, len);
                buff += len;
        }
        if (totlen >= TXBSIZE) {
                panic("%s: sonicput: packet overflow",
                    device_xname(sc->sc_dev));
        }

        SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FPTRLO,
            LOWER(mtdp->mtd_vbuf));
        SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FPTRHI,
            UPPER(mtdp->mtd_vbuf));

        if (totlen < ETHERMIN + ETHER_HDR_LEN) {
                int pad = ETHERMIN + ETHER_HDR_LEN - totlen;
                memset((char *)mtdp->mtd_buf + totlen, 0, pad);
                totlen = ETHERMIN + ETHER_HDR_LEN;
        }

        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));

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

        return totlen;
}

/*
 * These are called from sonicioctl() when /etc/ifconfig is run to set
 * the address or switch the i/f on.
 */
/*
 * CAM support
 */
static void
caminitialise(struct sn_softc *sc)
{
        void    *p_cda = sc->p_cda;
        int     i;
        int     camoffset;

        for (i = 0; i < MAXCAM; i++) {
                camoffset = i * CDA_CAMDESC;
                SWO(bitmode, p_cda, (camoffset + CDA_CAMEP), i);
                SWO(bitmode, p_cda, (camoffset + CDA_CAMAP2), 0);
                SWO(bitmode, p_cda, (camoffset + CDA_CAMAP1), 0);
                SWO(bitmode, p_cda, (camoffset + CDA_CAMAP0), 0);
        }
        SWO(bitmode, p_cda, CDA_ENABLE, 0);
}

static void
camentry(struct sn_softc *sc, int entry, const u_char *ea)
{
        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,
            (SRO(bitmode, p_cda, CDA_ENABLE) | (1 << entry)));
}

static void
camprogram(struct sn_softc *sc)
{
        struct ethercom *ec = &sc->sc_ethercom;
        struct ether_multistep step;
        struct ether_multi *enm;
        struct ifnet *ifp;
        int     timeout;
        int     mcount = 0;

        caminitialise(sc);

        ifp = &sc->sc_if;

        /* Always load our own address first. */
        camentry(sc, mcount, CLLADDR(ifp->if_sadl));
        mcount++;

        /* Assume we won't need allmulti bit. */
        ifp->if_flags &= ~IFF_ALLMULTI;

        /* Loop through multicast addresses */
        ETHER_LOCK(ec);
        ETHER_FIRST_MULTI(step, ec, enm);
        while (enm != NULL) {
                if (mcount == MAXCAM) {
                         ifp->if_flags |= IFF_ALLMULTI;
                         break;
                }

                if (memcmp(enm->enm_addrlo, enm->enm_addrhi,
                    sizeof(enm->enm_addrlo)) != 0) {
                        /*
                         * SONIC's CAM is programmed with specific
                         * addresses. It has no way to specify a range.
                         * (Well, thats not exactly true. If the
                         * range is small one could program each addr
                         * within the range as a separate CAM entry)
                         */
                        ifp->if_flags |= IFF_ALLMULTI;
                        break;
                }

                /* program the CAM with the specified entry */
                camentry(sc, mcount, enm->enm_addrlo);
                mcount++;

                ETHER_NEXT_MULTI(step, enm);
        }
        ETHER_UNLOCK(ec);

        NIC_PUT(sc, SNR_CDP, LOWER(sc->v_cda));
        NIC_PUT(sc, SNR_CDC, MAXCAM);
        NIC_PUT(sc, SNR_CR, CR_LCAM);
        wbflush();

        timeout = 10000;
        while ((NIC_GET(sc, SNR_CR) & CR_LCAM) && timeout--)
                delay(10);
        if (timeout == 0) {
                /* XXX */
                panic("%s: CAM initialisation failed",
                    device_xname(sc->sc_dev));
        }
        timeout = 10000;
        while (((NIC_GET(sc, SNR_ISR) & ISR_LCD) == 0) && timeout--)
                delay(10);

        if (NIC_GET(sc, SNR_ISR) & ISR_LCD)
                NIC_PUT(sc, SNR_ISR, ISR_LCD);
        else
                printf("%s: CAM initialisation without interrupt\n",
                    device_xname(sc->sc_dev));
}

#ifdef SNDEBUG
static void
camdump(struct sn_softc *sc)
{
        int     i;

        printf("CAM entries:\n");
        NIC_PUT(sc, SNR_CR, CR_RST);
        wbflush();

        for (i = 0; i < 16; i++) {
                ushort  ap2, ap1, ap0;
                NIC_PUT(sc, SNR_CEP, i);
                wbflush();
                ap2 = NIC_GET(sc, SNR_CAP2);
                ap1 = NIC_GET(sc, SNR_CAP1);
                ap0 = NIC_GET(sc, SNR_CAP0);
                printf("%d: ap2=0x%x ap1=0x%x ap0=0x%x\n", i, ap2, ap1, ap0);
        }
        printf("CAM enable 0x%x\n", NIC_GET(sc, SNR_CEP));

        NIC_PUT(sc, SNR_CR, 0);
        wbflush();
}
#endif

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

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

        sc->mtd_hw = 0;
        sc->mtd_prev = NTDA - 1;
        sc->mtd_free = 0;
        sc->mtd_tlinko = TXP_FRAGOFF + 1*TXP_FRAGSIZE + TXP_FPTRLO;
        sc->mtd_pint = NTDA/2;

        NIC_PUT(sc, SNR_UTDA, UPPER(sc->mtda[0].mtd_vtxp));
        NIC_PUT(sc, SNR_CTDA, LOWER(sc->mtda[0].mtd_vtxp));
        wbflush();
}

static void
initialise_rda(struct sn_softc *sc)
{
        int             i;
        char            *p_rda = 0;
        uint32_t        v_rda = 0;

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

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

        sc->sc_rxmark = 0;

        NIC_PUT(sc, SNR_URDA, UPPER(sc->v_rda));
        NIC_PUT(sc, SNR_CRDA, LOWER(sc->v_rda));
        wbflush();
}

static void
initialise_rra(struct sn_softc *sc)
{
        int     i;
        u_int   v;
        int     bitmode = sc->bitmode;

        if (bitmode)
                NIC_PUT(sc, SNR_EOBC, RBASIZE(sc) / 2 - 2);
        else
                NIC_PUT(sc, SNR_EOBC, RBASIZE(sc) / 2 - 1);

        NIC_PUT(sc, SNR_URRA, UPPER(sc->v_rra[0]));
        NIC_PUT(sc, SNR_RSA, LOWER(sc->v_rra[0]));
        /* rea must point just past the end of the rra space */
        NIC_PUT(sc, SNR_REA, LOWER(sc->v_rea));
        NIC_PUT(sc, SNR_RRP, LOWER(sc->v_rra[0]));
        NIC_PUT(sc, SNR_RSC, 0);

        /* fill up SOME of the rra with buffers */
        for (i = 0; i < NRBA; i++) {
                v = SONIC_GETDMA(sc, 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(PAGE_SIZE/2));
                SWO(bitmode, sc->p_rra[i], RXRSRC_WCLO, LOWER(PAGE_SIZE/2));
        }
        sc->sc_rramark = NRBA;
        NIC_PUT(sc, SNR_RWP, LOWER(sc->v_rra[sc->sc_rramark]));
        wbflush();
}

int
snintr(void *arg)
{
        struct sn_softc *sc = (struct sn_softc *)arg;
        int handled = 0;
        int     isr;

        while ((isr = (NIC_GET(sc, SNR_ISR) & ISR_ALL)) != 0) {
                /* scrub the interrupts that we are going to service */
                NIC_PUT(sc, SNR_ISR, isr);
                handled = 1;
                wbflush();

                if (isr & (ISR_BR | ISR_LCD | ISR_TC))
                        printf("%s: unexpected interrupt status 0x%x\n",
                            device_xname(sc->sc_dev), isr);

                if (isr & (ISR_TXDN | ISR_TXER | ISR_PINT))
                        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("%s: receive descriptors exhausted\n",
                                    device_xname(sc->sc_dev));
                        if (isr & ISR_RBE)
                                printf("%s: receive buffers exhausted\n",
                                    device_xname(sc->sc_dev));
                        if (isr & ISR_RBAE)
                                printf("%s: receive buffer area exhausted\n",
                                    device_xname(sc->sc_dev));
                        if (isr & ISR_RFO)
                                printf("%s: receive FIFO overrun\n",
                                    device_xname(sc->sc_dev));
                }
                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
                }
                if_schedule_deferred_start(&sc->sc_if);
        }
        return handled;
}

/*
 * Transmit interrupt routine
 */
static void
sonictxint(struct sn_softc *sc)
{
        struct mtd      *mtd;
        void            *txp;
        unsigned short  txp_status;
        int             mtd_hw;
        struct ifnet    *ifp = &sc->sc_if;

        mtd_hw = sc->mtd_hw;

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

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

                txp = mtd->mtd_txp;

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

#ifdef SNDEBUG
                {
                        struct ether_header *eh;

                        eh = (struct ether_header *) mtd->mtd_buf;
                        printf("%s: xmit status=0x%x len=%d type=0x%x from %s",
                            device_xname(sc->sc_dev),
                            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));
                }
#endif /* SNDEBUG */

                m_freem(mtd->mtd_mbuf);
                mtd->mtd_mbuf = NULL;
                if (++mtd_hw == NTDA) mtd_hw = 0;

                txp_status = SRO(sc->bitmode, txp, TXP_STATUS);

                if_statadd(ifp, if_collisions, (txp_status & TCR_EXC) ? 16 :
                        ((txp_status & TCR_NC) >> 12));

                if ((txp_status & TCR_PTX) == 0) {
                        if_statinc(ifp, if_oerrors);
                        printf("%s: Tx packet status=0x%x\n",
                            device_xname(sc->sc_dev), txp_status);

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

        sc->mtd_hw = mtd_hw;
        return;
}

/*
 * Receive interrupt routine
 */
static void
sonicrxint(struct sn_softc *sc)
{
        void *  rda;
        int     orra;
        int     len;
        int     rramark;
        int     rdamark;
        uint16_t rxpkt_ptr;

        rda = (char *)sc->p_rda + (sc->sc_rxmark * RXPKT_SIZE(sc));

        while (SRO(bitmode, rda, RXPKT_INUSE) == 0) {
                u_int status = SRO(bitmode, rda, RXPKT_STATUS);

                orra = RBASEQ(SRO(bitmode, rda, RXPKT_SEQNO)) & RRAMASK;
                rxpkt_ptr = SRO(bitmode, rda, RXPKT_PTRLO);
                len = SRO(bitmode, rda, RXPKT_BYTEC) - FCSSIZE;
                if (status & RCR_PRX) {
                        void *pkt =
                            (char *)sc->rbuf[orra & RBAMASK] +
                                 (rxpkt_ptr & PGOFSET);
                        if (sonic_read(sc, pkt, len) == 0)
                                if_statinc(&sc->sc_if, if_ierrors);
                } else
                        if_statinc(&sc->sc_if, if_ierrors);

                /*
                 * give receive buffer area back to chip.
                 *
                 * If this was the last packet in the RRA, give the RRA to
                 * the chip again.
                 * 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.
                 */
                if (status & RCR_LPKT) {
                        void *tmp1, *tmp2;

                        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;
                        NIC_PUT(sc, SNR_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, ((char *)sc->p_rda + (rdamark * RXPKT_SIZE(sc))),
                    RXPKT_RLINK,
                    SRO(bitmode, ((char *)sc->p_rda +
                        (rdamark * RXPKT_SIZE(sc))),
                    RXPKT_RLINK) & ~EOL);
                sc->sc_rdamark = sc->sc_rxmark;

                if (++sc->sc_rxmark >= sc->sc_nrda)
                        sc->sc_rxmark = 0;
                rda = (char *)sc->p_rda + (sc->sc_rxmark * RXPKT_SIZE(sc));
        }
}

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

        if (len < (ETHER_MIN_LEN - ETHER_CRC_LEN) ||
            len > (ETHER_MAX_LEN - ETHER_CRC_LEN)) {
                printf("%s: invalid packet length %d bytes\n",
                    device_xname(sc->sc_dev), len);
                return 0;
        }

#ifdef SNDEBUG
        {       
                struct ether_header eh_s, *eh = &eh_s;
                memcpy(eh, pkt, sizeof(*eh));
                CTASSERT(sizeof(*eh) <= ETHER_MIN_LEN);
                printf("%s: rcvd %p len=%d type=0x%x from %s",
                    device_xname(sc->sc_dev), eh, len, htons(eh->ether_type),
                    ether_sprintf(eh->ether_shost));
                printf(" (to %s)\n", ether_sprintf(eh->ether_dhost));
        }       
#endif /* SNDEBUG */

        m = sonic_get(sc, pkt, len);
        if (m == NULL)
                return 0;
        if_percpuq_enqueue(ifp->if_percpuq, m);
        return 1;
}

/*
 * munge the received packet into an mbuf chain
 */
static inline struct mbuf *
sonic_get(struct sn_softc *sc, void *pkt, int datalen)
{
        struct  mbuf *m, *top, **mp;
        int     len;

        MGETHDR(m, M_DONTWAIT, MT_DATA);
        if (m == 0)
                return 0;
        m_set_rcvif(m, &sc->sc_if);
        m->m_pkthdr.len = datalen;
        len = MHLEN;
        top = 0;
        mp = &top;

        while (datalen > 0) {
                if (top) {
                        MGET(m, M_DONTWAIT, MT_DATA);
                        if (m == 0) {
                                m_freem(top);
                                return 0;
                        }
                        len = MLEN;
                }
                if (datalen >= MINCLSIZE) {
                        MCLGET(m, M_DONTWAIT);
                        if ((m->m_flags & M_EXT) == 0) {
                                if (top)
                                        m_freem(top);
                                else
                                        m_freem(m);
                                return 0;
                        }
                        len = MCLBYTES;
                }

                if (mp == &top) {
                        char *newdata = (char *)
                            ALIGN((char *)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(datalen, len);

                memcpy(mtod(m, void *), pkt, (unsigned) len);
                pkt = (char *)pkt + len;
                datalen -= len;
                *mp = m;
                mp = &m->m_next;
        }

        return top;
}