/*    $OpenBSD: if_el.c,v 1.37 2022/04/06 18:59:28 naddy Exp $       */
/*      $NetBSD: if_el.c,v 1.39 1996/05/12 23:52:32 mycroft Exp $       */

/*
 * Copyright (c) 1994, Matthew E. Kimmel.  Permission is hereby granted
 * to use, copy, modify and distribute this software provided that both
 * the copyright notice and this permission notice appear in all copies
 * of the software, derivative works or modified versions, and any
 * portions thereof.
 */

/*
 * 3COM Etherlink 3C501 device driver
 */

/*
 * Bugs/possible improvements:
 *      - Does not currently support DMA
 *      - Does not currently support multicasts
 */

#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 <netinet/in.h>
#include <netinet/if_ether.h>

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

#include <machine/cpu.h>
#include <machine/intr.h>
#include <machine/pio.h>

#include <dev/isa/isavar.h>
#include <dev/isa/if_elreg.h>

/* for debugging convenience */
#ifdef EL_DEBUG
#define dprintf(x) printf x
#else
#define dprintf(x)
#endif

/*
 * per-line info and status
 */
struct el_softc {
        struct device sc_dev;
        void *sc_ih;

        struct arpcom sc_arpcom;        /* ethernet common */
        int sc_iobase;                  /* base I/O addr */
};

/*
 * prototypes
 */
int elintr(void *);
void elinit(struct el_softc *);
int elioctl(struct ifnet *, u_long, caddr_t);
void elstart(struct ifnet *);
void elwatchdog(struct ifnet *);
void elreset(struct el_softc *);
void elstop(struct el_softc *);
static int el_xmit(struct el_softc *);
void elread(struct el_softc *, int);
struct mbuf *elget(struct el_softc *sc, int);
static inline void el_hardreset(struct el_softc *);

int elprobe(struct device *, void *, void *);
void elattach(struct device *, struct device *, void *);

const struct cfattach el_ca = {
        sizeof(struct el_softc), elprobe, elattach
};

struct cfdriver el_cd = {
        NULL, "el", DV_IFNET
};

/*
 * Probe routine.
 *
 * See if the card is there and at the right place.
 * (XXX - cgd -- needs help)
 */
int
elprobe(struct device *parent, void *match, void *aux)
{
        struct el_softc *sc = match;
        struct isa_attach_args *ia = aux;
        int iobase = ia->ia_iobase;
        u_char station_addr[ETHER_ADDR_LEN];
        int i;

        /* First check the base. */
        if (iobase < 0x280 || iobase > 0x3f0)
                return 0;

        /* Grab some info for our structure. */
        sc->sc_iobase = iobase;

        /*
         * Now attempt to grab the station address from the PROM and see if it
         * contains the 3com vendor code.
         */
        dprintf(("Probing 3c501 at 0x%x...\n", iobase));

        /* Reset the board. */
        dprintf(("Resetting board...\n"));
        outb(iobase+EL_AC, EL_AC_RESET);
        delay(5);
        outb(iobase+EL_AC, 0);

        /* Now read the address. */
        dprintf(("Reading station address...\n"));
        for (i = 0; i < ETHER_ADDR_LEN; i++) {
                outb(iobase+EL_GPBL, i);
                station_addr[i] = inb(iobase+EL_EAW);
        }
        dprintf(("Address is %s\n", ether_sprintf(station_addr)));

        /*
         * If the vendor code is ok, return a 1.  We'll assume that whoever
         * configured this system is right about the IRQ.
         */
        if (station_addr[0] != 0x02 || station_addr[1] != 0x60 ||
            station_addr[2] != 0x8c) {
                dprintf(("Bad vendor code.\n"));
                return 0;
        }

        dprintf(("Vendor code ok.\n"));
        /* Copy the station address into the arpcom structure. */
        bcopy(station_addr, sc->sc_arpcom.ac_enaddr, ETHER_ADDR_LEN);

        ia->ia_iosize = 4;      /* XXX */
        ia->ia_msize = 0;
        return 1;
}

/*
 * Attach the interface to the kernel data structures.  By the time this is
 * called, we know that the card exists at the given I/O address.  We still
 * assume that the IRQ given is correct.
 */
void
elattach(struct device *parent, struct device *self, void *aux)
{
        struct el_softc *sc = (void *)self;
        struct isa_attach_args *ia = aux;
        struct ifnet *ifp = &sc->sc_arpcom.ac_if;

        dprintf(("Attaching %s...\n", sc->sc_dev.dv_xname));

        /* Stop the board. */
        elstop(sc);

        /* Initialize ifnet structure. */
        bcopy(sc->sc_dev.dv_xname, ifp->if_xname, IFNAMSIZ);
        ifp->if_softc = sc;
        ifp->if_start = elstart;
        ifp->if_ioctl = elioctl;
        ifp->if_watchdog = elwatchdog;
        ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX;

        /* Now we can attach the interface. */
        dprintf(("Attaching interface...\n"));
        if_attach(ifp);
        ether_ifattach(ifp);

        /* Print out some information for the user. */
        printf(": address %s\n", ether_sprintf(sc->sc_arpcom.ac_enaddr));

        sc->sc_ih = isa_intr_establish(ia->ia_ic, ia->ia_irq, IST_EDGE,
            IPL_NET, elintr, sc, sc->sc_dev.dv_xname);

        dprintf(("elattach() finished.\n"));
}

/*
 * Reset interface.
 */
void
elreset(struct el_softc *sc)
{
        int s;

        dprintf(("elreset()\n"));
        s = splnet();
        elstop(sc);
        elinit(sc);
        splx(s);
}

/*
 * Stop interface.
 */
void
elstop(struct el_softc *sc)
{

        outb(sc->sc_iobase+EL_AC, 0);
}

/*
 * Do a hardware reset of the board, and upload the ethernet address again in
 * case the board forgets.
 */
static inline void
el_hardreset(struct el_softc *sc)
{
        int iobase = sc->sc_iobase;
        int i;

        outb(iobase+EL_AC, EL_AC_RESET);
        delay(5);
        outb(iobase+EL_AC, 0);

        for (i = 0; i < ETHER_ADDR_LEN; i++)
                outb(iobase+i, sc->sc_arpcom.ac_enaddr[i]);
}

/*
 * Initialize interface.
 */
void
elinit(struct el_softc *sc)
{
        struct ifnet *ifp = &sc->sc_arpcom.ac_if;
        int iobase = sc->sc_iobase;

        /* First, reset the board. */
        el_hardreset(sc);

        /* Configure rx. */
        dprintf(("Configuring rx...\n"));
        if (ifp->if_flags & IFF_PROMISC)
                outb(iobase+EL_RXC, EL_RXC_AGF | EL_RXC_DSHORT | EL_RXC_DDRIB | EL_RXC_DOFLOW | EL_RXC_PROMISC);
        else
                outb(iobase+EL_RXC, EL_RXC_AGF | EL_RXC_DSHORT | EL_RXC_DDRIB | EL_RXC_DOFLOW | EL_RXC_ABROAD);
        outb(iobase+EL_RBC, 0);

        /* Configure TX. */
        dprintf(("Configuring tx...\n"));
        outb(iobase+EL_TXC, 0);

        /* Start reception. */
        dprintf(("Starting reception...\n"));
        outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);

        /* Set flags appropriately. */
        ifp->if_flags |= IFF_RUNNING;
        ifq_clr_oactive(&ifp->if_snd);

        /* And start output. */
        elstart(ifp);
}

/*
 * Start output on interface.  Get datagrams from the queue and output them,
 * giving the receiver a chance between datagrams.  Call only from splnet or
 * interrupt level!
 */
void
elstart(struct ifnet *ifp)
{
        struct el_softc *sc = ifp->if_softc;
        int iobase = sc->sc_iobase;
        struct mbuf *m, *m0;
        int s, i, off, retries;

        dprintf(("elstart()...\n"));
        s = splnet();

        /* Don't do anything if output is active. */
        if (ifq_is_oactive(&ifp->if_snd) != 0) {
                splx(s);
                return;
        }

        ifq_set_oactive(&ifp->if_snd);

        /*
         * The main loop.  They warned me against endless loops, but would I
         * listen?  NOOO....
         */
        for (;;) {
                /* Dequeue the next datagram. */
                m0 = ifq_dequeue(&ifp->if_snd);

                /* If there's nothing to send, return. */
                if (m0 == NULL)
                        break;

#if NBPFILTER > 0
                /* Give the packet to the bpf, if any. */
                if (ifp->if_bpf)
                        bpf_mtap(ifp->if_bpf, m0, BPF_DIRECTION_OUT);
#endif

                /* Disable the receiver. */
                outb(iobase+EL_AC, EL_AC_HOST);
                outb(iobase+EL_RBC, 0);

                /* Transfer datagram to board. */
                dprintf(("el: xfr pkt length=%d...\n", m0->m_pkthdr.len));
                off = EL_BUFSIZ - max(m0->m_pkthdr.len, ETHER_MIN_LEN);
                outb(iobase+EL_GPBL, off);
                outb(iobase+EL_GPBH, off >> 8);

                /* Copy the datagram to the buffer. */
                for (m = m0; m != 0; m = m->m_next)
                        outsb(iobase+EL_BUF, mtod(m, caddr_t), m->m_len);
                for (i = 0;
                    i < ETHER_MIN_LEN - ETHER_CRC_LEN - m0->m_pkthdr.len; i++)
                        outb(iobase+EL_BUF, 0);
                        
                m_freem(m0);

                /* Now transmit the datagram. */
                retries = 0;
                for (;;) {
                        outb(iobase+EL_GPBL, off);
                        outb(iobase+EL_GPBH, off >> 8);
                        if (el_xmit(sc)) {
                                ifp->if_oerrors++;
                                break;
                        }
                        /* Check out status. */
                        i = inb(iobase+EL_TXS);
                        dprintf(("tx status=0x%x\n", i));
                        if ((i & EL_TXS_READY) == 0) {
                                dprintf(("el: err txs=%x\n", i));
                                if (i & (EL_TXS_COLL | EL_TXS_COLL16)) {
                                        ifp->if_collisions++;
                                        if ((i & EL_TXC_DCOLL16) == 0 &&
                                            retries < 15) {
                                                retries++;
                                                outb(iobase+EL_AC, EL_AC_HOST);
                                        }
                                } else {
                                        ifp->if_oerrors++;
                                        break;
                                }
                        } else {
                                break;
                        }
                }

                /*
                 * Now give the card a chance to receive.
                 * Gotta love 3c501s...
                 */
                (void)inb(iobase+EL_AS);
                outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
                splx(s);
                /* Interrupt here. */
                s = splnet();
        }

        (void)inb(iobase+EL_AS);
        outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
        ifq_clr_oactive(&ifp->if_snd);
        splx(s);
}

/*
 * This function actually attempts to transmit a datagram downloaded to the
 * board.  Call at splnet or interrupt, after downloading data!  Returns 0 on
 * success, non-0 on failure.
 */
static int
el_xmit(struct el_softc *sc)
{
        int iobase = sc->sc_iobase;
        int i;

        /*
         * XXX
         * This busy-waits for the tx completion.  Can we get an interrupt
         * instead?
         */

        dprintf(("el: xmit..."));
        outb(iobase+EL_AC, EL_AC_TXFRX);
        i = 20000;
        while ((inb(iobase+EL_AS) & EL_AS_TXBUSY) && (i > 0))
                i--;
        if (i == 0) {
                dprintf(("tx not ready\n"));
                return -1;
        }
        dprintf(("%d cycles.\n", 20000 - i));
        return 0;
}

/*
 * Controller interrupt.
 */
int
elintr(void *arg)
{
        register struct el_softc *sc = arg;
        int iobase = sc->sc_iobase;
        int rxstat, len;

        dprintf(("elintr: "));

        /* Check board status. */
        if ((inb(iobase+EL_AS) & EL_AS_RXBUSY) != 0) {
                (void)inb(iobase+EL_RXC);
                outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
                return 0;
        }

        for (;;) {
                rxstat = inb(iobase+EL_RXS);
                if (rxstat & EL_RXS_STALE)
                        break;

                /* If there's an overflow, reinit the board. */
                if ((rxstat & EL_RXS_NOFLOW) == 0) {
                        dprintf(("overflow.\n"));
                        el_hardreset(sc);
                        /* Put board back into receive mode. */
                        if (sc->sc_arpcom.ac_if.if_flags & IFF_PROMISC)
                                outb(iobase+EL_RXC, EL_RXC_AGF | EL_RXC_DSHORT | EL_RXC_DDRIB | EL_RXC_DOFLOW | EL_RXC_PROMISC);
                        else
                                outb(iobase+EL_RXC, EL_RXC_AGF | EL_RXC_DSHORT | EL_RXC_DDRIB | EL_RXC_DOFLOW | EL_RXC_ABROAD);
                        (void)inb(iobase+EL_AS);
                        outb(iobase+EL_RBC, 0);
                        break;
                }

                /* Incoming packet. */
                len = inb(iobase+EL_RBL);
                len |= inb(iobase+EL_RBH) << 8;
                dprintf(("receive len=%d rxstat=%x ", len, rxstat));
                outb(iobase+EL_AC, EL_AC_HOST);

                /* Pass data up to upper levels. */
                elread(sc, len);

                /* Is there another packet? */
                if ((inb(iobase+EL_AS) & EL_AS_RXBUSY) != 0)
                        break;

                dprintf(("<rescan> "));
        }

        (void)inb(iobase+EL_RXC);
        outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
        return 1;
}

/*
 * Pass a packet to the higher levels.
 */
void
elread(struct el_softc *sc, int len)
{
        struct ifnet *ifp = &sc->sc_arpcom.ac_if;
        struct mbuf_list ml = MBUF_LIST_INITIALIZER();
        struct mbuf *m;

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

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

        ml_enqueue(&ml, m);
        if_input(ifp, &ml);
}

/*
 * Pull read data off a interface.  Len is length of data, with local net
 * header stripped.  We copy the data into mbufs.  When full cluster sized
 * units are present we copy into clusters.
 */
struct mbuf *
elget(struct el_softc *sc, int totlen)
{
        int iobase = sc->sc_iobase;
        struct mbuf *top, **mp, *m;
        int len;

        MGETHDR(m, M_DONTWAIT, MT_DATA);
        if (m == NULL)
                return 0;
        m->m_pkthdr.len = totlen;
        len = MHLEN;
        top = 0;
        mp = &top;

        outb(iobase+EL_GPBL, 0);
        outb(iobase+EL_GPBH, 0);

        while (totlen > 0) {
                if (top) {
                        MGET(m, M_DONTWAIT, MT_DATA);
                        if (m == NULL) {
                                m_freem(top);
                                return 0;
                        }
                        len = MLEN;
                }
                if (totlen >= MINCLSIZE) {
                        MCLGET(m, M_DONTWAIT);
                        if (m->m_flags & M_EXT)
                                len = MCLBYTES;
                }
                m->m_len = len = min(totlen, len);
                insb(iobase+EL_BUF, mtod(m, caddr_t), len);
                totlen -= len;
                *mp = m;
                mp = &m->m_next;
        }

        outb(iobase+EL_RBC, 0);
        outb(iobase+EL_AC, EL_AC_RX);

        return top;
}

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

        s = splnet();

        switch (cmd) {
        case SIOCSIFADDR:
                ifp->if_flags |= IFF_UP;
                elinit(sc);
                break;

        case SIOCSIFFLAGS:
                if ((ifp->if_flags & IFF_UP) == 0 &&
                    (ifp->if_flags & IFF_RUNNING) != 0) {
                        /*
                         * If interface is marked down and it is running, then
                         * stop it.
                         */
                        elstop(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.
                         */
                        elinit(sc);
                } else {
                        /*
                         * Some other important flag might have changed, so
                         * reset.
                         */
                        elreset(sc);
                }
                break;

        default:
                error = ether_ioctl(ifp, &sc->sc_arpcom, cmd, data);
        }

        splx(s);
        return error;
}

/*
 * Device timeout routine.
 */
void
elwatchdog(struct ifnet *ifp)
{
        struct el_softc *sc = ifp->if_softc;

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

        elreset(sc);
}