/*      $NetBSD: am79c950.c,v 1.52 2024/06/29 12:11:10 riastradh Exp $  */

/*-
* Copyright (c) 1997 David Huang <[email protected]>
* All rights reserved.
*
* Portions of this code are based on code by Denton Gentry <[email protected]>,
* Charles M. Hannum, Yanagisawa Takeshi <[email protected]>, and
* Jason R. Thorpe.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. The name of the author may not be used to endorse or promote products
*    derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/

/*
* Driver for the AMD Am79C940 (MACE) ethernet chip, used for onboard
* ethernet on the Centris/Quadra 660av and Quadra 840av.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: am79c950.c,v 1.52 2024/06/29 12:11:10 riastradh 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 <sys/bus.h>

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

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

#include <macppc/dev/am79c950reg.h>
#include <macppc/dev/if_mcvar.h>

hide void       mcwatchdog(struct ifnet *);
hide int        mcinit(struct mc_softc *);
hide int        mcstop(struct mc_softc *);
hide int        mcioctl(struct ifnet *, u_long, void *);
hide void       mcstart(struct ifnet *);
hide void       mcreset(struct mc_softc *);

integrate u_int maceput(struct mc_softc *, struct mbuf *);
integrate void  mc_tint(struct mc_softc *);
integrate void  mace_read(struct mc_softc *, uint8_t *, int);
integrate struct mbuf *mace_get(struct mc_softc *, uint8_t *, int);
static void     mace_calcladrf(struct ethercom *, uint8_t *);
static inline uint16_t ether_cmp(void *, void *);
static int      mc_mediachange(struct ifnet *);
static void     mc_mediastatus(struct ifnet *, struct ifmediareq *);

/*
* Compare two Ether/802 addresses for equality, inlined and
* unrolled for speed.  Use this like memcmp().
*
* XXX: Add <machine/inlines.h> for stuff like this?
* XXX: or maybe add it to libkern.h instead?
*
* "I'd love to have an inline assembler version of this."
* XXX: Who wanted that? mycroft?  I wrote one, but this
* version in C is as good as hand-coded assembly. -gwr
*
* Please do NOT tweak this without looking at the actual
* assembly code generated before and after your tweaks!
*/
static inline uint16_t
ether_cmp(void *one, void *two)
{
       register uint16_t *a = (u_short *) one;
       register uint16_t *b = (u_short *) two;
       register uint16_t diff;

#ifdef  m68k
       /*
        * The post-increment-pointer form produces the best
        * machine code for m68k.  This was carefully tuned
        * so it compiles to just 8 short (2-byte) op-codes!
        */
       diff  = *a++ - *b++;
       diff |= *a++ - *b++;
       diff |= *a++ - *b++;
#else
       /*
        * Most modern CPUs do better with a single expression.
        * Note that short-cut evaluation is NOT helpful here,
        * because it just makes the code longer, not faster!
        */
       diff = (a[0] - b[0]) | (a[1] - b[1]) | (a[2] - b[2]);
#endif

       return diff;
}

#define ETHER_CMP       ether_cmp

/*
* Interface exists: make available by filling in network interface
* record.  System will initialize the interface when it is ready
* to accept packets.
*/
int
mcsetup(struct mc_softc *sc, uint8_t *lladdr)
{
       struct ifnet *ifp = &sc->sc_if;

       /* Reset the chip and disable all interrupts */
       NIC_PUT(sc, MACE_BIUCC, SWRST);
       DELAY(100);
       NIC_PUT(sc, MACE_IMR, ~0);

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

       memcpy(ifp->if_xname, device_xname(sc->sc_dev), IFNAMSIZ);
       ifp->if_softc = sc;
       ifp->if_ioctl = mcioctl;
       ifp->if_start = mcstart;
       ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
       ifp->if_watchdog = mcwatchdog;

       /* Initialize ifmedia structures */
       sc->sc_ethercom.ec_ifmedia = &sc->sc_media;
       ifmedia_init(&sc->sc_media, 0, mc_mediachange, mc_mediastatus);
       ifmedia_add(&sc->sc_media, IFM_ETHER | IFM_MANUAL, 0, NULL);
       ifmedia_set(&sc->sc_media, IFM_ETHER | IFM_MANUAL);

       if_attach(ifp);
       if_deferred_start_init(ifp, NULL);
       ether_ifattach(ifp, lladdr);

       return 0;
}

hide int
mcioctl(struct ifnet *ifp, u_long cmd, void *data)
{
       struct mc_softc *sc = ifp->if_softc;
       struct ifaddr *ifa;

       int     s = splnet(), err = 0;

       switch (cmd) {

       case SIOCINITIFADDR:
               ifa = (struct ifaddr *)data;
               ifp->if_flags |= IFF_UP;
               mcinit(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;
               /* XXX see the comment in ed_ioctl() about code re-use */
               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.
                        */
                       mcstop(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)mcinit(sc);
               } else {
                       /*
                        * Reset the interface to pick up any other changes
                        * in flags
                        */
                       mcreset(sc);
                       mcstart(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)
                               mcreset(sc);
                       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.
*/
hide void
mcstart(struct ifnet *ifp)
{
       struct mc_softc *sc = ifp->if_softc;
       struct mbuf     *m;

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

       while (!sc->sc_txbusy) {
               IF_DEQUEUE(&ifp->if_snd, m);
               if (m == 0)
                       return;

               /*
                * 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);

               /* Copy the mbuf chain into the transmit buffer. */
               sc->sc_txbusy = true;
               maceput(sc, m);

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

/*
* Reset and restart the MACE.  Called in case of fatal
* hardware/software errors.
*/
hide void
mcreset(struct mc_softc *sc)
{
       mcstop(sc);
       mcinit(sc);
}

hide int
mcinit(struct mc_softc *sc)
{
       int s;
       uint8_t maccc, ladrf[8];

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

       s = splnet();

       NIC_PUT(sc, MACE_BIUCC, sc->sc_biucc);
       NIC_PUT(sc, MACE_FIFOCC, sc->sc_fifocc);
       NIC_PUT(sc, MACE_IMR, ~0); /* Disable all interrupts */
       NIC_PUT(sc, MACE_PLSCC, sc->sc_plscc);

       NIC_PUT(sc, MACE_UTR, RTRD); /* Disable reserved test registers */

       /* Set MAC address */
       NIC_PUT(sc, MACE_IAC, ADDRCHG);
       while (NIC_GET(sc, MACE_IAC) & ADDRCHG)
               ;
       NIC_PUT(sc, MACE_IAC, PHYADDR);
       bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_PADR),
           sc->sc_enaddr, ETHER_ADDR_LEN);

       /* Set logical address filter */
       mace_calcladrf(&sc->sc_ethercom, ladrf);

       NIC_PUT(sc, MACE_IAC, ADDRCHG);
       while (NIC_GET(sc, MACE_IAC) & ADDRCHG)
               ;
       NIC_PUT(sc, MACE_IAC, LOGADDR);
       bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_LADRF),
           ladrf, 8);

       NIC_PUT(sc, MACE_XMTFC, APADXMT);
       /*
        * No need to autostrip padding on receive... Ethernet frames
        * don't have a length field, unlike 802.3 frames, so the MACE
        * can't figure out the length of the packet anyways.
        */
       NIC_PUT(sc, MACE_RCVFC, 0);

       maccc = ENXMT | ENRCV;
       if (sc->sc_if.if_flags & IFF_PROMISC)
               maccc |= PROM;

       NIC_PUT(sc, MACE_MACCC, maccc);

       if (sc->sc_bus_init)
               (*sc->sc_bus_init)(sc);

       /*
        * Enable all interrupts except receive, since we use the DMA
        * completion interrupt for that.
        */
       NIC_PUT(sc, MACE_IMR, RCVINTM);

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

       splx(s);
       return 0;
}

/*
* Close down an interface and free its buffers
* Called on final close of device, or if mcinit() fails part way through.
*/
hide int
mcstop(struct mc_softc *sc)
{
       int     s = splnet();

       NIC_PUT(sc, MACE_BIUCC, SWRST);
       DELAY(100);

       sc->sc_if.if_timer = 0;
       sc->sc_if.if_flags &= ~IFF_RUNNING;

       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.
*/
hide void
mcwatchdog(struct ifnet *ifp)
{
       struct mc_softc *sc = ifp->if_softc;

       printf("mcwatchdog: resetting chip\n");
       mcreset(sc);
}

/*
* Stuff packet into MACE (at splnet)
*/
integrate u_int
maceput(struct mc_softc *sc, struct mbuf *m)
{
       struct mbuf *n;
       u_int len, totlen = 0;
       u_char *buff;

       buff = sc->sc_txbuf;

       for (; m; m = n) {
               u_char *data = mtod(m, u_char *);
               len = m->m_len;
               totlen += len;
               memcpy(buff, data, len);
               buff += len;
               n = m_free(m);
       }

       if (totlen > PAGE_SIZE)
               panic("%s: maceput: packet overflow", device_xname(sc->sc_dev));

#if 0
       if (totlen < ETHERMIN + sizeof(struct ether_header)) {
               int pad = ETHERMIN + sizeof(struct ether_header) - totlen;
               memset(sc->sc_txbuf + totlen, 0, pad);
               totlen = ETHERMIN + sizeof(struct ether_header);
       }
#endif

       (*sc->sc_putpacket)(sc, totlen);

       sc->sc_if.if_timer = 5; /* 5 seconds to watch for failing to transmit */
       return totlen;
}

int
mcintr(void *arg)
{
       struct mc_softc *sc = arg;
       uint8_t ir;

       ir = NIC_GET(sc, MACE_IR) & ~NIC_GET(sc, MACE_IMR);
       if (ir == 0)
               return 0;

       if (ir & JAB) {
#ifdef MCDEBUG
               printf("%s: jabber error\n", device_xname(sc->sc_dev));
#endif
               if_statinc(&sc->sc_if, if_oerrors);
       }

       if (ir & BABL) {
#ifdef MCDEBUG
               printf("%s: babble\n", device_xname(sc->sc_dev));
#endif
               if_statinc(&sc->sc_if, if_oerrors);
       }

       if (ir & CERR) {
               printf("%s: collision error\n", device_xname(sc->sc_dev));
               if_statinc(&sc->sc_if, if_collisions);
       }

       /*
        * Pretend we have carrier; if we don't this will be cleared
        * shortly.
        */
       const int ocarrier = sc->sc_havecarrier;
       sc->sc_havecarrier = 1;

       if (ir & XMTINT)
               mc_tint(sc);

       if (ir & RCVINT)
               mc_rint(sc);

       if (sc->sc_havecarrier != ocarrier)
               if_link_state_change(&sc->sc_if,
                   sc->sc_havecarrier ? LINK_STATE_UP : LINK_STATE_DOWN);

       return 1;
}

integrate void
mc_tint(struct mc_softc *sc)
{
       uint8_t xmtfs;

       (void)NIC_GET(sc, MACE_XMTRC);
       xmtfs = NIC_GET(sc, MACE_XMTFS);

       if ((xmtfs & XMTSV) == 0)
               return;

       if (xmtfs & UFLO) {
               printf("%s: underflow\n", device_xname(sc->sc_dev));
               mcreset(sc);
               return;
       }

       net_stat_ref_t nsr = IF_STAT_GETREF(&sc->sc_if);
       if (xmtfs & LCOL) {
               printf("%s: late collision\n", device_xname(sc->sc_dev));
               if_statinc_ref(&sc->sc_if, nsr, if_oerrors);
               if_statinc_ref(&sc->sc_if, nsr, if_collisions);
       }

       if (xmtfs & MORE)
               /* Real number is unknown. */
               if_statadd_ref(&sc->sc_if, nsr, if_collisions, 2);
       else if (xmtfs & ONE)
               if_statinc_ref(&sc->sc_if, nsr, if_collisions);
       else if (xmtfs & RTRY) {
               if_statadd_ref(&sc->sc_if, nsr, if_collisions, 16);
               if_statinc_ref(&sc->sc_if, nsr, if_oerrors);
       }

       if (xmtfs & LCAR) {
               sc->sc_havecarrier = 0;
               printf("%s: lost carrier\n", device_xname(sc->sc_dev));
               if_statinc_ref(&sc->sc_if, nsr, if_oerrors);
       }
       IF_STAT_PUTREF(&sc->sc_if);

       sc->sc_txbusy = false;
       sc->sc_if.if_timer = 0;
       if_schedule_deferred_start(&sc->sc_if);
}

void
mc_rint(struct mc_softc *sc)
{
#define rxf     sc->sc_rxframe
       u_int len;

       len = (rxf.rx_rcvcnt | ((rxf.rx_rcvsts & 0xf) << 8)) - 4;

#ifdef MCDEBUG
       if (rxf.rx_rcvsts & 0xf0)
               printf("%s: rcvcnt %02x rcvsts %02x rntpc 0x%02x rcvcc 0x%02x\n",
                   device_xname(sc->sc_dev), rxf.rx_rcvcnt, rxf.rx_rcvsts,
                   rxf.rx_rntpc, rxf.rx_rcvcc);
#endif

       if (rxf.rx_rcvsts & OFLO) {
               printf("%s: receive FIFO overflow\n", device_xname(sc->sc_dev));
               if_statinc(&sc->sc_if, if_ierrors);
               return;
       }

       if (rxf.rx_rcvsts & CLSN)
               if_statinc(&sc->sc_if, if_collisions);

       if (rxf.rx_rcvsts & FRAM) {
#ifdef MCDEBUG
               printf("%s: framing error\n", device_xname(sc->sc_dev));
#endif
               if_statinc(&sc->sc_if, if_ierrors);
               return;
       }

       if (rxf.rx_rcvsts & FCS) {
#ifdef MCDEBUG
               printf("%s: frame control checksum error\n",
                   device_xname(sc->sc_dev));
#endif
               if_statinc(&sc->sc_if, if_ierrors);
               return;
       }

       mace_read(sc, rxf.rx_frame, len);
#undef  rxf
}

integrate void
mace_read(struct mc_softc *sc, uint8_t *pkt, int len)
{
       struct ifnet *ifp = &sc->sc_if;
       struct mbuf *m;

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

       m = mace_get(sc, pkt, len);
       if (m == NULL) {
               if_statinc(ifp, if_ierrors);
               return;
       }

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

/*
* Pull data off an interface.
* Len is length of data, with local net header stripped.
* We copy the data into mbufs.  When full cluster sized units are present
* we copy into clusters.
*/
integrate struct mbuf *
mace_get(struct mc_softc *sc, uint8_t *pkt, int totlen)
{
       register struct mbuf *m;
       struct mbuf *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 = totlen;
       len = MHLEN;
       top = 0;
       mp = &top;

       while (totlen > 0) {
               if (top) {
                       MGET(m, M_DONTWAIT, MT_DATA);
                       if (m == 0) {
                               m_freem(top);
                               return 0;
                       }
                       len = MLEN;
               }
               if (totlen >= MINCLSIZE) {
                       MCLGET(m, M_DONTWAIT);
                       if ((m->m_flags & M_EXT) == 0) {
                               m_free(m);
                               m_freem(top);
                               return 0;
                       }
                       len = MCLBYTES;
               }
               m->m_len = len = uimin(totlen, len);
               memcpy(mtod(m, void *), pkt, len);
               pkt += len;
               totlen -= len;
               *mp = m;
               mp = &m->m_next;
       }

       return top;
}

/*
* Go through the list of multicast addresses and calculate the logical
* address filter.
*/
void
mace_calcladrf(struct ethercom *ec, uint8_t *af)
{
       struct ifnet *ifp = &ec->ec_if;
       struct ether_multi *enm;
       register u_char *cp, c;
       register uint32_t 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.
        */

       *((uint32_t *)af) = *((uint32_t *)af + 1) = 0;

       ETHER_LOCK(ec);
       ETHER_FIRST_MULTI(step, ec, enm);
       while (enm != NULL) {
               if (ETHER_CMP(enm->enm_addrlo, enm->enm_addrhi)) {
                       /*
                        * We must listen to a range of multicast addresses.
                        * For now, just accept all multicasts, rather than
                        * trying to set only those filter bits needed to match
                        * the range.  (At this time, the only use of address
                        * ranges is for IP multicast routing, for which the
                        * range is big enough to require all bits set.)
                        */
                       ETHER_UNLOCK(ec);
                       goto allmulti;
               }

               cp = enm->enm_addrlo;
               crc = 0xffffffff;
               for (len = sizeof(enm->enm_addrlo); --len >= 0;) {
                       c = *cp++;
                       for (i = 8; --i >= 0;) {
                               if ((crc & 0x01) ^ (c & 0x01)) {
                                       crc >>= 1;
                                       crc ^= 0xedb88320;
                               } else
                                       crc >>= 1;
                               c >>= 1;
                       }
               }
               /* Just want the 6 most significant bits. */
               crc >>= 26;

               /* Set the corresponding bit in the filter. */
               af[crc >> 3] |= 1 << (crc & 7);

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

allmulti:
       ifp->if_flags |= IFF_ALLMULTI;
       *((uint32_t *)af) = *((uint32_t *)af + 1) = 0xffffffff;
}

int
mc_mediachange(struct ifnet *ifp)
{
       return EINVAL;
}

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

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

       if (sc->sc_havecarrier)
               ifmr->ifm_status |= IFM_ACTIVE;
}