Expand PMF_FN_* macros.

[netbsd-mini2440.git] / sys / arch / amiga / dev / if_ed.c

/*      $NetBSD: if_ed.c,v 1.59 2009/05/19 18:39:26 phx Exp $ */

/*
 * Device driver for National Semiconductor DS8390/WD83C690 based ethernet
 * adapters.
 *
 * Copyright (c) 1994, 1995 Charles M. Hannum.  All rights reserved.
 *
 * Copyright (C) 1993, David Greenman.  This software may be used, modified,
 * copied, distributed, and sold, in both source and binary form provided that
 * the above copyright and these terms are retained.  Under no circumstances is
 * the author responsible for the proper functioning of this software, nor does
 * the author assume any responsibility for damages incurred with its use.
 *
 * Currently supports the Hydra Systems ethernet card.
 */

#include "opt_inet.h"
#include "opt_ns.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: if_ed.c,v 1.59 2009/05/19 18:39:26 phx Exp $");

#include "bpfilter.h"

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

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

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

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

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

#include <machine/cpu.h>

#include <amiga/amiga/device.h>
#include <amiga/amiga/isr.h>
#include <amiga/dev/zbusvar.h>
#include <dev/ic/dp8390reg.h>
#include <amiga/dev/if_edreg.h>

#define HYDRA_MANID     2121
#define HYDRA_PRODID    1

#define ASDG_MANID      1023
#define ASDG_PRODID     254

/*
 * ed_softc: per line info and status
 */
struct ed_softc {
        struct  device sc_dev;
        struct  isr sc_isr;

        struct  ethercom sc_ethercom;   /* ethernet common */

        u_char  volatile *nic_addr;     /* NIC (DS8390) I/O address */

        u_char  cr_proto;       /* values always set in CR */

        void *  mem_start;      /* NIC memory start address */
        void *  mem_end;        /* NIC memory end address */
        u_long  mem_size;       /* total NIC memory size */
        void *  mem_ring;       /* start of RX ring-buffer (in NIC mem) */

        u_char  xmit_busy;      /* transmitter is busy */
        u_char  txb_cnt;        /* number of transmit buffers */
        u_char  txb_inuse;      /* number of TX buffers currently in-use*/

        u_char  txb_new;        /* pointer to where new buffer will be added */
        u_char  txb_next_tx;    /* pointer to next buffer ready to xmit */
        u_short txb_len[8];     /* buffered xmit buffer lengths */
        u_char  tx_page_start;  /* first page of TX buffer area */
        u_char  rec_page_start; /* first page of RX ring-buffer */
        u_char  rec_page_stop;  /* last page of RX ring-buffer */
        u_char  next_packet;    /* pointer to next unread RX packet */
};

int ed_zbus_match(struct device *, struct cfdata *, void *);
void ed_zbus_attach(struct device *, struct device *, void *);
int edintr(void *);
int ed_ioctl(struct ifnet *, u_long, void *);
void ed_start(struct ifnet *);
void ed_watchdog(struct ifnet *);
void ed_reset(struct ed_softc *);
void ed_init(struct ed_softc *);
void ed_stop(struct ed_softc *);
void ed_getmcaf(struct ethercom *, u_long *);
u_short ed_put(struct ed_softc *, struct mbuf *, void *);

#define inline  /* XXX for debugging porpoises */

void ed_get_packet(struct ed_softc *, void *, u_short);
static inline void ed_rint(struct ed_softc *);
static inline void ed_xmit(struct ed_softc *);
static inline void *ed_ring_copy(struct ed_softc *, void *, void *,
                                        u_short);

static inline void NIC_PUT(struct ed_softc *, int, u_char);
static inline u_char NIC_GET(struct ed_softc *, int);
static inline void word_copy(void *, void *, int);
static inline void word_zero(void *, int);
struct mbuf *ed_ring_to_mbuf(struct ed_softc *, void *, struct mbuf *,
                                        u_short);

CFATTACH_DECL(ed_zbus, sizeof(struct ed_softc),
    ed_zbus_match, ed_zbus_attach, NULL, NULL);

static inline void
NIC_PUT(struct ed_softc *sc, int off, u_char val)
{
        sc->nic_addr[off * 2] = val;
#ifdef not_def
        /*
         * This was being used to *slow* access to the bus.  I don't
         * believe it is needed but I'll leave it around incase probelms
         * pop-up
         */
        (void)ciaa.pra;
#endif
}

static inline u_char
NIC_GET(struct ed_softc *sc, int off)
{
        register u_char val;

        val = sc->nic_addr[off * 2];
#ifdef not_def
        /*
         * This was being used to *slow* access to the bus.  I don't
         * believe it is needed but I'll leave it around incase probelms
         * pop-up
         */
        (void)ciaa.pra;
#endif
        return (val);
}

/*
 * Memory copy, copies word at time.
 */
static inline void
word_copy(void *a, void *b, int len)
{
        u_short *x = (u_short *)a,
                *y = (u_short *)b;

        len >>= 1;
        while (len--)
                *y++ = *x++;
}

/*
 * zero memory, one word at time.
 */
static inline void
word_zero(void *a, int len)
{
        u_short *x = (u_short *)a;

        len >>= 1;
        while (len--)
                *x++ = 0;
}

int
ed_zbus_match(struct device *parent, struct cfdata *cfp, void *aux)
{
        struct zbus_args *zap = aux;

        if (zap->manid == HYDRA_MANID && zap->prodid == HYDRA_PRODID)
                return (1);
        else if (zap->manid == ASDG_MANID && zap->prodid == ASDG_PRODID)
                return (1);
        return (0);
}

void
ed_zbus_attach(struct device *parent, struct device *self, void *aux)
{
        struct ed_softc *sc = (void *)self;
        struct zbus_args *zap = aux;
        struct cfdata *cf = device_cfdata(&sc->sc_dev);
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;
        volatile u_char *prom;
        int i;
        u_int8_t myaddr[ETHER_ADDR_LEN];

        if (zap->manid == HYDRA_MANID) {
                sc->mem_start = zap->va;
                sc->mem_size = 16384;
                sc->nic_addr = (u_char *)sc->mem_start + HYDRA_NIC_BASE;
                prom = (u_char *)sc->mem_start + HYDRA_ADDRPROM;
        } else {
                sc->mem_start = (u_char *)zap->va + 0x8000;
                sc->mem_size = 16384;
                sc->nic_addr = (volatile u_char *)zap->va + ASDG_NIC_BASE;
                prom = (volatile u_char *)sc->nic_addr + ASDG_ADDRPROM;
        }
        sc->cr_proto = ED_CR_RD2;
        sc->tx_page_start = 0;

        sc->mem_end = (u_char *)sc->mem_start + sc->mem_size;

        /*
         * Use one xmit buffer if < 16k, two buffers otherwise (if not told
         * otherwise).
         */
        if ((sc->mem_size < 16384) || zap->manid == ASDG_MANID
            || (cf->cf_flags & ED_FLAGS_NO_MULTI_BUFFERING))
                sc->txb_cnt = 1;
        else
                sc->txb_cnt = 2;

        sc->rec_page_start = sc->tx_page_start + sc->txb_cnt * ED_TXBUF_SIZE;
        sc->rec_page_stop = sc->tx_page_start + (sc->mem_size >> ED_PAGE_SHIFT);

        sc->mem_ring =
            (u_char *)sc->mem_start + 
                ((sc->txb_cnt * ED_TXBUF_SIZE) << ED_PAGE_SHIFT);

        /*
         * Interrupts must be inactive when reading the prom, as the interrupt
         * line is shared with one of its address lines.
         */

        NIC_PUT(sc, ED_P0_IMR, 0x00); /* disable ints */
        NIC_PUT(sc, ED_P0_ISR, 0xff); /* clear ints */

        /*
         * read the ethernet address from the board
         */
        for (i = 0; i < ETHER_ADDR_LEN; i++)
                myaddr[i] = *(prom + 2 * i);

        /* Set interface to stopped condition (reset). */
        ed_stop(sc);

        /* Initialize ifnet structure. */
        memcpy(ifp->if_xname, sc->sc_dev.dv_xname, IFNAMSIZ);
        ifp->if_softc = sc;
        ifp->if_start = ed_start;
        ifp->if_ioctl = ed_ioctl;
        ifp->if_watchdog = ed_watchdog;
        ifp->if_flags =
            IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS | IFF_MULTICAST;

        /* Attach the interface. */
        if_attach(ifp);
        ether_ifattach(ifp, myaddr);

        /* Print additional info when attached. */
        printf(": address %s\n", ether_sprintf(myaddr));

        sc->sc_isr.isr_intr = edintr;
        sc->sc_isr.isr_arg = sc;
        sc->sc_isr.isr_ipl = 2;
        add_isr(&sc->sc_isr);
}

/*
 * Reset interface.
 */
void
ed_reset(struct ed_softc *sc)
{
        int s;

        s = splnet();
        ed_stop(sc);
        ed_init(sc);
        splx(s);
        log(LOG_ERR, "%s: reset\n", sc->sc_dev.dv_xname);
}

/*
 * Take interface offline.
 */
void
ed_stop(struct ed_softc *sc)
{
        int n = 5000;

        /* Stop everything on the interface, and select page 0 registers. */
        NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STP);

        /*
         * Wait for interface to enter stopped state, but limit # of checks to
         * 'n' (about 5ms).  It shouldn't even take 5us on modern DS8390's, but
         * just in case it's an old one.
         */
        while (((NIC_GET(sc, ED_P0_ISR) & ED_ISR_RST) == 0) && --n);
}

/*
 * Device timeout/watchdog routine.  Entered if the device neglects to generate
 * an interrupt after a transmit has been started on it.
 */
void
ed_watchdog(struct ifnet *ifp)
{
        struct ed_softc *sc = ifp->if_softc;

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

        ed_reset(sc);
}

/*
 * Initialize device.
 */
void
ed_init(struct ed_softc *sc)
{
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;
        int i, s;
        u_long mcaf[2];

        /*
         * Initialize the NIC in the exact order outlined in the NS manual.
         * This init procedure is "mandatory"...don't change what or when
         * things happen.
         */
        s = splnet();

        /* Reset transmitter flags. */
        sc->xmit_busy = 0;
        ifp->if_timer = 0;

        sc->txb_inuse = 0;
        sc->txb_new = 0;
        sc->txb_next_tx = 0;

        /* Set interface for page 0, remote DMA complete, stopped. */
        NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STP);

        /*
         * Set FIFO threshold to 8, No auto-init Remote DMA, byte
         * order=68k, word-wide DMA xfers,
         * XXX changed to use 2 word threshhold
         */
        NIC_PUT(sc, ED_P0_DCR,
            ED_DCR_FT0 | ED_DCR_WTS | ED_DCR_LS | ED_DCR_BOS);

        /* Clear remote byte count registers. */
        NIC_PUT(sc, ED_P0_RBCR0, 0);
        NIC_PUT(sc, ED_P0_RBCR1, 0);

        /* Tell RCR to do nothing for now. */
        NIC_PUT(sc, ED_P0_RCR, ED_RCR_MON);

        /* Place NIC in internal loopback mode. */
        NIC_PUT(sc, ED_P0_TCR, ED_TCR_LB0);

        /* Initialize receive buffer ring. */
        NIC_PUT(sc, ED_P0_BNRY, sc->rec_page_start);
        NIC_PUT(sc, ED_P0_PSTART, sc->rec_page_start);
        NIC_PUT(sc, ED_P0_PSTOP, sc->rec_page_stop);

        /*
         * Clear all interrupts.  A '1' in each bit position clears the
         * corresponding flag.
         */
        NIC_PUT(sc, ED_P0_ISR, 0xff);

        /*
         * Enable the following interrupts: receive/transmit complete,
         * receive/transmit error, and Receiver OverWrite.
         *
         * Counter overflow and Remote DMA complete are *not* enabled.
         */
        NIC_PUT(sc, ED_P0_IMR,
            ED_IMR_PRXE | ED_IMR_PTXE | ED_IMR_RXEE | ED_IMR_TXEE |
            ED_IMR_OVWE);

        /* Program command register for page 1. */
        NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_1 | ED_CR_STP);

        /* Copy out our station address. */
        for (i = 0; i < ETHER_ADDR_LEN; ++i)
                NIC_PUT(sc, ED_P1_PAR0 + i, CLLADDR(ifp->if_sadl)[i]);

        /* Set multicast filter on chip. */
        ed_getmcaf(&sc->sc_ethercom, mcaf);
        for (i = 0; i < 8; i++)
                NIC_PUT(sc, ED_P1_MAR0 + i, ((u_char *)mcaf)[i]);

        /*
         * Set current page pointer to one page after the boundary pointer, as
         * recommended in the National manual.
         */
        sc->next_packet = sc->rec_page_start + 1;
        NIC_PUT(sc, ED_P1_CURR, sc->next_packet);

        /* Program command register for page 0. */
        NIC_PUT(sc, ED_P1_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STP);

        i = ED_RCR_AB | ED_RCR_AM;
        if (ifp->if_flags & IFF_PROMISC) {
                /*
                 * Set promiscuous mode.  Multicast filter was set earlier so
                 * that we should receive all multicast packets.
                 */
                i |= ED_RCR_PRO | ED_RCR_AR | ED_RCR_SEP;
        }
        NIC_PUT(sc, ED_P0_RCR, i);

        /* Take interface out of loopback. */
        NIC_PUT(sc, ED_P0_TCR, 0);

        /* Fire up the interface. */
        NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STA);

        /* Set 'running' flag, and clear output active flag. */
        ifp->if_flags |= IFF_RUNNING;
        ifp->if_flags &= ~IFF_OACTIVE;

        /* ...and attempt to start output. */
        ed_start(ifp);

        splx(s);
}

/*
 * This routine actually starts the transmission on the interface.
 */
static inline void
ed_xmit(struct ed_softc *sc)
{
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;
        u_short len;

        len = sc->txb_len[sc->txb_next_tx];

        /* Set NIC for page 0 register access. */
        NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STA);

        /* Set TX buffer start page. */
        NIC_PUT(sc, ED_P0_TPSR, sc->tx_page_start +
            sc->txb_next_tx * ED_TXBUF_SIZE);

        /* Set TX length. */
        NIC_PUT(sc, ED_P0_TBCR0, len);
        NIC_PUT(sc, ED_P0_TBCR1, len >> 8);

        /* Set page 0, remote DMA complete, transmit packet, and *start*. */
        NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_TXP | ED_CR_STA);
        sc->xmit_busy = 1;

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

        /* Set a timer just in case we never hear from the board again. */
        ifp->if_timer = 2;
}

/*
 * Start output on interface.
 * We make two assumptions here:
 *  1) that the current priority is set to splnet _before_ this code
 *     is called *and* is returned to the appropriate priority after
 *     return
 *  2) that the IFF_OACTIVE flag is checked before this code is called
 *     (i.e. that the output part of the interface is idle)
 */
void
ed_start(struct ifnet *ifp)
{
        struct ed_softc *sc = ifp->if_softc;
        struct mbuf *m0, *m;
        void *buffer;
        int len;

outloop:
        /*
         * First, see if there are buffered packets and an idle transmitter -
         * should never happen at this point.
         */
        if (sc->txb_inuse && (sc->xmit_busy == 0)) {
                printf("%s: packets buffered, but transmitter idle\n",
                    sc->sc_dev.dv_xname);
                ed_xmit(sc);
        }

        /* See if there is room to put another packet in the buffer. */
        if (sc->txb_inuse == sc->txb_cnt) {
                /* No room.  Indicate this to the outside world and exit. */
                ifp->if_flags |= IFF_OACTIVE;
                return;
        }

        IF_DEQUEUE(&ifp->if_snd, m);
        if (m == 0) {
                /*
                 * We are using the !OACTIVE flag to indicate to the outside
                 * world that we can accept an additional packet rather than
                 * that the transmitter is _actually_ active.  Indeed, the
                 * transmitter may be active, but if we haven't filled all the
                 * buffers with data then we still want to accept more.
                 */
                ifp->if_flags &= ~IFF_OACTIVE;
                return;
        }

        /* Copy the mbuf chain into the transmit buffer. */
        m0 = m;

        /* txb_new points to next open buffer slot. */
        buffer = (char*)sc->mem_start +
                ((sc->txb_new * ED_TXBUF_SIZE) << ED_PAGE_SHIFT);

        len = ed_put(sc, m, buffer);

        sc->txb_len[sc->txb_new] = len;
        sc->txb_inuse++;

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

        if (sc->xmit_busy == 0)
                ed_xmit(sc);

#if NBPFILTER > 0
        /* Tap off here if there is a BPF listener. */
        if (ifp->if_bpf)
                bpf_mtap(ifp->if_bpf, m0);
#endif

        m_freem(m0);

        /* Loop back to the top to possibly buffer more packets. */
        goto outloop;
}

/*
 * Ethernet interface receiver interrupt.
 */
static inline void
ed_rint(struct ed_softc *sc)
{
        struct ifnet *ifp;
        void *packet_ptr;
        u_short len;
        u_char nlen;
        u_char boundary, current;
        struct ed_ring packet_hdr;

        ifp = &sc->sc_ethercom.ec_if;
loop:
        /* Set NIC to page 1 registers to get 'current' pointer. */
        NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_1 | ED_CR_STA);

        /*
         * 'sc->next_packet' is the logical beginning of the ring-buffer - i.e.
         * it points to where new data has been buffered.  The 'CURR' (current)
         * register points to the logical end of the ring-buffer - i.e. it
         * points to where additional new data will be added.  We loop here
         * until the logical beginning equals the logical end (or in other
         * words, until the ring-buffer is empty).
         */
        current = NIC_GET(sc, ED_P1_CURR);
        if (sc->next_packet == current)
                return;

        /* Set NIC to page 0 registers to update boundary register. */
        NIC_PUT(sc, ED_P1_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STA);

        do {
                /* Get pointer to this buffer's header structure. */
                packet_ptr = (char*)sc->mem_ring +
                    ((sc->next_packet - sc->rec_page_start) << ED_PAGE_SHIFT);

                /*
                 * The byte count includes a 4 byte header that was added by
                 * the NIC.
                 */
                packet_hdr = *(struct ed_ring *)packet_ptr;
                packet_hdr.count = ((packet_hdr.count >> 8) & 0xff)
                     | ((packet_hdr.count & 0xff) << 8);
                len = packet_hdr.count;
                /*
                 * Try do deal with old, buggy chips that sometimes duplicate
                 * the low byte of the length into the high byte.  We do this
                 * by simply ignoring the high byte of the length and always
                 * recalculating it.
                 *
                 * NOTE: sc->next_packet is pointing at the current packet.
                 */
                if (packet_hdr.next_packet >= sc->next_packet)
                        nlen = (packet_hdr.next_packet - sc->next_packet);
                else
                        nlen = ((packet_hdr.next_packet - sc->rec_page_start) +
                                (sc->rec_page_stop - sc->next_packet));
                --nlen;
                if ((len & ED_PAGE_MASK) + sizeof(packet_hdr) > ED_PAGE_SIZE)
                        --nlen;
                len = (len & ED_PAGE_MASK) | (nlen << ED_PAGE_SHIFT);
#ifdef DIAGNOSTIC
                if (len != packet_hdr.count) {
                        printf("%s: length does not match next packet pointer\n",
                            sc->sc_dev.dv_xname);
                        printf("%s: len %04x nlen %04x start %02x first %02x curr %02x next %02x stop %02x\n",
                            sc->sc_dev.dv_xname, packet_hdr.count, len,
                            sc->rec_page_start, sc->next_packet, current,
                            packet_hdr.next_packet, sc->rec_page_stop);
                }
#endif

                /*
                 * Be fairly liberal about what we allow as a "reasonable"
                 * length so that a [crufty] packet will make it to BPF (and
                 * can thus be analyzed).  Note that all that is really
                 * important is that we have a length that will fit into one
                 * mbuf cluster or less; the upper layer protocols can then
                 * figure out the length from their own length field(s).
                 *
                 * MCLBYTES may be less than a valid packet len.  Thus
                 * we use a constant that is large enough.
                 */
                if (len <= 2048 &&
                    packet_hdr.next_packet >= sc->rec_page_start &&
                    packet_hdr.next_packet < sc->rec_page_stop) {
                        /* Go get packet. */
                        ed_get_packet(sc, (char*)packet_ptr +
                            sizeof(struct ed_ring),
                            len - sizeof(struct ed_ring));
                        ++ifp->if_ipackets;
                } else {
                        /* Really BAD.  The ring pointers are corrupted. */
#ifdef DEBUG_AMIGA_IF_ED
                        log(LOG_ERR,
                            "%s: NIC memory corrupt - invalid packet length %d\n",
                            sc->sc_dev.dv_xname, len);
#endif
                        ++ifp->if_ierrors;
                        ed_reset(sc);
                        return;
                }

                /* Update next packet pointer. */
                sc->next_packet = packet_hdr.next_packet;

                /*
                 * Update NIC boundary pointer - being careful to keep it one
                 * buffer behind (as recommended by NS databook).
                 */
                boundary = sc->next_packet - 1;
                if (boundary < sc->rec_page_start)
                        boundary = sc->rec_page_stop - 1;
                NIC_PUT(sc, ED_P0_BNRY, boundary);
        } while (sc->next_packet != current);

        goto loop;
}

/* Ethernet interface interrupt processor. */
int
edintr(void *arg)
{
        struct ed_softc *sc = arg;
        struct ifnet *ifp = &sc->sc_ethercom.ec_if;
        u_char isr;

        /* Set NIC to page 0 registers. */
        NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STA);

        isr = NIC_GET(sc, ED_P0_ISR);
        if (!isr)
                return (0);

        /* Loop until there are no more new interrupts. */
        for (;;) {
                /*
                 * Reset all the bits that we are 'acknowledging' by writing a
                 * '1' to each bit position that was set.
                 * (Writing a '1' *clears* the bit.)
                 */
                NIC_PUT(sc, ED_P0_ISR, isr);

                /*
                 * Handle transmitter interrupts.  Handle these first because
                 * the receiver will reset the board under some conditions.
                 */
                if (isr & (ED_ISR_PTX | ED_ISR_TXE)) {
                        u_char collisions = NIC_GET(sc, ED_P0_NCR) & 0x0f;

                        /*
                         * Check for transmit error.  If a TX completed with an
                         * error, we end up throwing the packet away.  Really
                         * the only error that is possible is excessive
                         * collisions, and in this case it is best to allow the
                         * automatic mechanisms of TCP to backoff the flow.  Of
                         * course, with UDP we're screwed, but this is expected
                         * when a network is heavily loaded.
                         */
                        (void) NIC_GET(sc, ED_P0_TSR);
                        if (isr & ED_ISR_TXE) {
                                /*
                                 * Excessive collisions (16).
                                 */
                                if ((NIC_GET(sc, ED_P0_TSR) & ED_TSR_ABT)
                                    && (collisions == 0)) {
                                        /*
                                         * When collisions total 16, the P0_NCR
                                         * will indicate 0, and the TSR_ABT is
                                         * set.
                                         */
                                        collisions = 16;
                                }

                                /* Update output errors counter. */
                                ++ifp->if_oerrors;
                        } else {
                                /*
                                 * Update total number of successfully
                                 * transmitted packets.
                                 */
                                ++ifp->if_opackets;
                        }

                        /* Reset TX busy and output active flags. */
                        sc->xmit_busy = 0;
                        ifp->if_flags &= ~IFF_OACTIVE;

                        /* Clear watchdog timer. */
                        ifp->if_timer = 0;

                        /*
                         * Add in total number of collisions on last
                         * transmission.
                         */
                        ifp->if_collisions += collisions;

                        /*
                         * Decrement buffer in-use count if not zero (can only
                         * be zero if a transmitter interrupt occurred while not
                         * actually transmitting).
                         * If data is ready to transmit, start it transmitting,
                         * otherwise defer until after handling receiver.
                         */
                        if (sc->txb_inuse && --sc->txb_inuse)
                                ed_xmit(sc);
                }

                /* Handle receiver interrupts. */
                if (isr & (ED_ISR_PRX | ED_ISR_RXE | ED_ISR_OVW)) {
                        /*
                         * Overwrite warning.  In order to make sure that a
                         * lockup of the local DMA hasn't occurred, we reset
                         * and re-init the NIC.  The NSC manual suggests only a
                         * partial reset/re-init is necessary - but some chips
                         * seem to want more.  The DMA lockup has been seen
                         * only with early rev chips - Methinks this bug was
                         * fixed in later revs.  -DG
                         */
                        if (isr & ED_ISR_OVW) {
                                ++ifp->if_ierrors;
#ifdef DIAGNOSTIC
                                log(LOG_WARNING,
                                    "%s: warning - receiver ring buffer overrun\n",
                                    sc->sc_dev.dv_xname);
#endif
                                /* Stop/reset/re-init NIC. */
                                ed_reset(sc);
                        } else {
                                /*
                                 * Receiver Error.  One or more of: CRC error,
                                 * frame alignment error FIFO overrun, or
                                 * missed packet.
                                 */
                                if (isr & ED_ISR_RXE) {
                                        ++ifp->if_ierrors;
#ifdef ED_DEBUG
                                        printf("%s: receive error %x\n",
                                            sc->sc_dev.dv_xname,
                                            NIC_GET(sc, ED_P0_RSR));
#endif
                                }

                                /*
                                 * Go get the packet(s).
                                 * XXX - Doing this on an error is dubious
                                 * because there shouldn't be any data to get
                                 * (we've configured the interface to not
                                 * accept packets with errors).
                                 */
                                ed_rint(sc);
                        }
                }

                /*
                 * If it looks like the transmitter can take more data, attempt
                 * to start output on the interface.  This is done after
                 * handling the receiver to give the receiver priority.
                 */
                if ((ifp->if_flags & IFF_OACTIVE) == 0)
                        ed_start(ifp);

                /*
                 * Return NIC CR to standard state: page 0, remote DMA
                 * complete, start (toggling the TXP bit off, even if was just
                 * set in the transmit routine, is *okay* - it is 'edge'
                 * triggered from low to high).
                 */
                NIC_PUT(sc, ED_P0_CR, sc->cr_proto | ED_CR_PAGE_0 | ED_CR_STA);

                /*
                 * If the Network Talley Counters overflow, read them to reset
                 * them.  It appears that old 8390's won't clear the ISR flag
                 * otherwise - resulting in an infinite loop.
                 */
                if (isr & ED_ISR_CNT) {
                        (void) NIC_GET(sc, ED_P0_CNTR0);
                        (void) NIC_GET(sc, ED_P0_CNTR1);
                        (void) NIC_GET(sc, ED_P0_CNTR2);
                }

                isr = NIC_GET(sc, ED_P0_ISR);
                if (!isr)
                        return (1);
        }
}

/*
 * Process an ioctl request.  This code needs some work - it looks pretty ugly.
 */
int
ed_ioctl(register struct ifnet *ifp, u_long cmd, void *data)
{
        struct ed_softc *sc = ifp->if_softc;
        register struct ifaddr *ifa = (struct ifaddr *)data;
        int s, error = 0;

        s = splnet();

        switch (cmd) {

        case SIOCINITIFADDR:
                ifp->if_flags |= IFF_UP;

                switch (ifa->ifa_addr->sa_family) {
#ifdef INET
                case AF_INET:
                        ed_init(sc);
                        arp_ifinit(ifp, ifa);
                        break;
#endif
#ifdef NS
                /* XXX - This code is probably wrong. */
                case AF_NS:
                    {
                        register 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), ETHER_ADDR_LEN);
                        /* Set new address. */
                        ed_init(sc);
                        break;
                    }
#endif
                default:
                        ed_init(sc);
                        break;
                }
                break;

        case SIOCSIFFLAGS:
                if ((error = ifioctl_common(ifp, cmd, data)) != 0)
                        break;
                /* XXX if ed_init() would ed_stop(, 0), first, perhaps we
                 * can re-use the code in ether_ioctl().
                 */
                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.
                         */
                        ed_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.
                         */
                        ed_init(sc);
                } else {
                        /*
                         * Reset the interface to pick up changes in any other
                         * flags that affect hardware registers.
                         */
                        ed_stop(sc);
                        ed_init(sc);
                }
                break;

        case SIOCADDMULTI:
        case SIOCDELMULTI:
                /* Update our multicast list. */
                if ((error = ether_ioctl(ifp, cmd, data)) == ENETRESET) {
                        /*
                         * Multicast list has changed; set the hardware filter
                         * accordingly.
                         */
                        if (ifp->if_flags & IFF_RUNNING) {
                                ed_stop(sc); /* XXX for ds_setmcaf? */
                                ed_init(sc);
                        }
                        error = 0;
                }
                break;

        default:
                error = ether_ioctl(ifp, cmd, data);
                break;
        }

        splx(s);
        return (error);
}

/*
 * Retrieve packet from shared memory and send to the next level up via
 * ether_input().  If there is a BPF listener, give a copy to BPF, too.
 */
void
ed_get_packet(struct ed_softc *sc, void *buf, u_short len)
{
        struct mbuf *m;
        struct ifnet *ifp;

        ifp = &sc->sc_ethercom.ec_if;

        /* round length to word boundry */
        len = (len + 1) & ~1;

        /* Allocate a header mbuf. */
        MGETHDR(m, M_DONTWAIT, MT_DATA);
        if (m == 0)
                return;
        m->m_pkthdr.rcvif = ifp;
        m->m_pkthdr.len = len;
        m->m_len = 0;

        /* The following silliness is to make NFS happy. */
#define EROUND  ((sizeof(struct ether_header) + 3) & ~3)
#define EOFF    (EROUND - sizeof(struct ether_header))

        /*
         * The following assumes there is room for the ether header in the
         * header mbuf.
         */
        m->m_data += EOFF;

        word_copy(buf, mtod(m, void *), sizeof(struct ether_header));
        buf = (char*)buf + sizeof(struct ether_header);
        m->m_len += sizeof(struct ether_header);
        len -= sizeof(struct ether_header);

        /* Pull packet off interface. */
        if (ed_ring_to_mbuf(sc, buf, m, len) == 0) {
                m_freem(m);
                return;
        }

#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)
                bpf_mtap(ifp->if_bpf, m);
#endif

        (*ifp->if_input)(ifp, m);
}

/*
 * Supporting routines.
 */

/*
 * Given a source and destination address, copy 'amount' of a packet from the
 * ring buffer into a linear destination buffer.  Takes into account ring-wrap.
 */
static inline void *
ed_ring_copy(struct ed_softc *sc, void *src, void *dst, u_short amount)
{
        u_short tmp_amount;

        /* Does copy wrap to lower addr in ring buffer? */
        if ((char*)src + amount > (char*)sc->mem_end) {
                tmp_amount = (char*)sc->mem_end - (char*)src;

                /* Copy amount up to end of NIC memory. */
                word_copy(src, dst, tmp_amount);

                amount -= tmp_amount;
                src = sc->mem_ring;
                dst = (char*)dst + tmp_amount;
        }

        word_copy(src, dst, amount);

        return ((char*)src + amount);
}

/*
 * Copy data from receive buffer to end of mbuf chain allocate additional mbufs
 * as needed.  Return pointer to last mbuf in chain.
 * sc = ed info (softc)
 * src = pointer in ed ring buffer
 * dst = pointer to last mbuf in mbuf chain to copy to
 * amount = amount of data to copy
 */
struct mbuf *
ed_ring_to_mbuf(struct ed_softc *sc, void *src, struct mbuf *dst,
                u_short total_len)
{
        register struct mbuf *m = dst;

        /* Round the length to a word boundary. */
        /* total_len = (total_len + 1) & ~1; */

        while (total_len) {
                register u_short amount = min(total_len, M_TRAILINGSPACE(m));

                if (amount == 0) {
                        /*
                         * No more data in this mbuf; alloc another.
                         *
                         * If there is enough data for an mbuf cluster, attempt
                         * to allocate one of those, otherwise, a regular mbuf
                         * will do.
                         * Note that a regular mbuf is always required, even if
                         * we get a cluster - getting a cluster does not
                         * allocate any mbufs, and one is needed to assign the
                         * cluster to.  The mbuf that has a cluster extension
                         * can not be used to contain data - only the cluster
                         * can contain data.
                         */
                        dst = m;
                        MGET(m, M_DONTWAIT, MT_DATA);
                        if (m == 0)
                                return (0);

                        if (total_len >= MINCLSIZE)
                                MCLGET(m, M_DONTWAIT);

                        m->m_len = 0;
                        dst->m_next = m;
                        amount = min(total_len, M_TRAILINGSPACE(m));
                }

                src = ed_ring_copy(sc, src, mtod(m, char *) + m->m_len,
                    amount);

                m->m_len += amount;
                total_len -= amount;
        }
        return (m);
}

/*
 * Compute the multicast address filter from the list of multicast addresses we
 * need to listen to.
 */
void
ed_getmcaf(struct ethercom *ac, u_long *af)
{
        struct ifnet *ifp = &ac->ec_if;
        struct ether_multi *enm;
        register u_char *cp, c;
        register u_long crc;
        register int i, len;
        struct ether_multistep step;

        /*
         * Set up multicast address filter by passing all multicast addresses
         * through a crc generator, and then using the high order 6 bits as an
         * index into the 64 bit logical address filter.  The high order bit
         * selects the word, while the rest of the bits select the bit within
         * the word.
         */

        if (ifp->if_flags & IFF_PROMISC) {
                ifp->if_flags |= IFF_ALLMULTI;
                af[0] = af[1] = 0xffffffff;
                return;
        }

        af[0] = af[1] = 0;
        ETHER_FIRST_MULTI(step, ac, enm);
        while (enm != NULL) {
                if (memcmp(enm->enm_addrlo, enm->enm_addrhi,
                    sizeof(enm->enm_addrlo)) != 0) {
                        /*
                         * 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.)
                         */
                        ifp->if_flags |= IFF_ALLMULTI;
                        af[0] = af[1] = 0xffffffff;
                        return;
                }

                cp = enm->enm_addrlo;
                crc = 0xffffffff;
                for (len = sizeof(enm->enm_addrlo); --len >= 0;) {
                        c = *cp++;
                        for (i = 8; --i >= 0;) {
                                if (((crc & 0x80000000) ? 1 : 0) ^ (c & 0x01)) {
                                        crc <<= 1;
                                        crc ^= 0x04c11db6 | 1;
                                } else
                                        crc <<= 1;
                                c >>= 1;
                        }
                }
                /* Just want the 6 most significant bits. */
                crc >>= 26;

                /* Turn on the corresponding bit in the filter. */
                af[crc >> 5] |= 1 << ((crc & 0x1f) ^ 0);

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

/*
 * Copy packet from mbuf to the board memory
 *
 * Currently uses an extra buffer/extra memory copy,
 * unless the whole packet fits in one mbuf.
 *
 */
u_short
ed_put(struct ed_softc *sc, struct mbuf *m, void *buf)
{
        u_char *data, savebyte[2];
        int len, wantbyte;
        u_short totlen;

        totlen = wantbyte = 0;

        for (; m != 0; m = m->m_next) {
                data = mtod(m, u_char *);
                len = m->m_len;
                totlen += len;
                if (len > 0) {
                        /* Finish the last word. */
                        if (wantbyte) {
                                savebyte[1] = *data;
                                word_copy(savebyte, buf, 2);
                                buf = (char*)buf + 2;
                                data++;
                                len--;
                                wantbyte = 0;
                        }
                        /* Output contiguous words. */
                        if (len > 1) {
                                word_copy(data, buf, len);
                                buf = (char*)buf + (len & ~1);
                                data += len & ~1;
                                len &= 1;
                        }
                        /* Save last byte, if necessary. */
                        if (len == 1) {
                                savebyte[0] = *data;
                                wantbyte = 1;
                        }
                }
        }

        if (wantbyte) {
                savebyte[1] = 0;
                word_copy(savebyte, buf, 2);
                buf = (char*)buf + 2;
                totlen++;
        }
        if (totlen < ETHER_MIN_LEN - ETHER_CRC_LEN) {
                word_zero(buf, ETHER_MIN_LEN - ETHER_CRC_LEN - totlen);
                totlen = ETHER_MIN_LEN - ETHER_CRC_LEN;
        }

        return (totlen);
}