FreeBSD/Linux Kernel Cross Reference
sys/dev/ic/midway.c

     /*      $NetBSD: midway.c,v 1.66 2005/02/27 00:27:02 perry Exp $        */
     /*      (sync'd to midway.c 1.68)       */
     
     /*
      *
      * Copyright (c) 1996 Charles D. Cranor and Washington University.
      * All rights reserved.
      *
      * 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. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by Charles D. Cranor and
     *      Washington University.
     * 4. 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.
     */
    
    /*
     *
     * m i d w a y . c   e n i 1 5 5   d r i v e r
     *
     * author: Chuck Cranor <chuck@ccrc.wustl.edu>
     * started: spring, 1996 (written from scratch).
     *
     * notes from the author:
     *   Extra special thanks go to Werner Almesberger, EPFL LRC.   Werner's
     *   ENI driver was especially useful in figuring out how this card works.
     *   I would also like to thank Werner for promptly answering email and being
     *   generally helpful.
     */
    /*
     *  1997/12/02, major update on 1999/04/06 kjc
     *    new features added:
     *      - BPF support (link type is DLT_ATM_RFC1483)
     *        BPF understands only LLC/SNAP!! (because bpf can't
     *        handle variable link header length.)
     *        (bpfwrite should work if atm_pseudohdr and LLC/SNAP are prepended.)
     *      - support vc shaping
     *      - integrate IPv6 support.
     *      - support pvc sub interface
     *
     *        initial work on per-pvc-interface for ipv6 was done
     *        by Katsushi Kobayashi <ikob@cc.uec.ac.jp> of the WIDE Project.
     *        some of the extensions for pvc subinterfaces are merged from
     *        the CAIRN project written by Suresh Bhogavilli (suresh@isi.edu).
     *
     *    code cleanup:
     *      - remove WMAYBE related code.  ENI WMAYBE DMA doesn't work.
     *      - remove updating if_lastchange for every packet.
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: midway.c,v 1.66 2005/02/27 00:27:02 perry Exp $");
    
    #include "opt_natm.h"
    
    #undef  EN_DEBUG
    #undef  EN_DEBUG_RANGE          /* check ranges on en_read/en_write's? */
    #define EN_MBUF_OPT             /* try and put more stuff in mbuf? */
    #define EN_DIAG
    #define EN_STAT
    #ifndef EN_DMA
    #define EN_DMA          1       /* use DMA? */
    #endif
    #define EN_NOTXDMA      0       /* hook to disable tx DMA only */
    #define EN_NORXDMA      0       /* hook to disable rx DMA only */
    #define EN_NOWMAYBE     1       /* hook to disable word maybe DMA */
                                    /* XXX: WMAYBE doesn't work, needs debugging */
    #define EN_DDBHOOK      1       /* compile in ddb functions */
    #if defined(MIDWAY_ADPONLY)
    #define EN_ENIDMAFIX    0       /* no ENI cards to worry about */
    #else
    #define EN_ENIDMAFIX    1       /* avoid byte DMA on the ENI card (see below) */
    #endif
    
    /*
     * note on EN_ENIDMAFIX: the byte aligner on the ENI version of the card
     * appears to be broken.   it works just fine if there is no load... however
     * when the card is loaded the data get corrupted.   to see this, one only
     * has to use "telnet" over ATM.   do the following command in "telnet":
     *      cat /usr/share/misc/termcap
    * "telnet" seems to generate lots of 1023 byte mbufs (which make great
    * use of the byte aligner).   watch "netstat -s" for checksum errors.
    *
    * I further tested this by adding a function that compared the transmit
    * data on the card's SRAM with the data in the mbuf chain _after_ the
    * "transmit DMA complete" interrupt.   using the "telnet" test I got data
    * mismatches where the byte-aligned data should have been.   using ddb
    * and en_dumpmem() I verified that the DTQs fed into the card were
    * absolutely correct.   thus, we are forced to concluded that the ENI
    * hardware is buggy.   note that the Adaptec version of the card works
    * just fine with byte DMA.
    *
    * bottom line: we set EN_ENIDMAFIX to 1 to avoid byte DMAs on the ENI
    * card.
    */
   
   #if defined(DIAGNOSTIC) && !defined(EN_DIAG)
   #define EN_DIAG                 /* link in with master DIAG option */
   #endif
   #ifdef EN_STAT
   #define EN_COUNT(X) (X)++
   #else
   #define EN_COUNT(X) /* nothing */
   #endif
   
   #ifdef EN_DEBUG
   #undef  EN_DDBHOOK
   #define EN_DDBHOOK      1
   #define STATIC /* nothing */
   #define INLINE /* nothing */
   #else /* EN_DEBUG */
   #define STATIC static
   #define INLINE inline
   #endif /* EN_DEBUG */
   
   #ifdef __FreeBSD__
   #include "en.h"
   #endif
   
   #ifdef __NetBSD__
   #include "opt_ddb.h"
   #include "opt_inet.h"
   #else
   #define bitmask_snprintf(q,f,b,l) snprintf((b), (l), "%b", (q), (f))
   #endif
   
   #if NEN > 0 || !defined(__FreeBSD__)
   
   #include <sys/param.h>
   #include <sys/systm.h>
   #if defined(__NetBSD__) || defined(__OpenBSD__) || defined(__bsdi__)
   #include <sys/device.h>
   #endif
   #if defined(__FreeBSD__)
   #include <sys/sockio.h>
   #else
   #include <sys/ioctl.h>
   #endif
   #include <sys/mbuf.h>
   #include <sys/socket.h>
   #include <sys/socketvar.h>
   #include <sys/queue.h>
   #include <sys/proc.h>
   
   #include <net/if.h>
   #include <net/if_atm.h>
   
   #ifdef __NetBSD__
   #include <uvm/uvm_extern.h>
   #else
   #include <vm/vm.h>
   #endif
   
   #if defined(INET) || defined(INET6)
   #include <netinet/in.h>
   #include <netinet/if_atm.h>
   #ifdef INET6
   #include <netinet6/in6_var.h>
   #endif
   #endif
   
   #ifdef NATM
   #if !(defined(INET) || defined(INET6))
   #include <netinet/in.h>
   #endif
   #include <netnatm/natm.h>
   #endif
   
   
   #if !defined(__FreeBSD__)
   #include <machine/bus.h>
   
   #endif
   
   #if defined(__NetBSD__) || defined(__OpenBSD__)
   #include <dev/ic/midwayreg.h>
   #include <dev/ic/midwayvar.h>
   #if defined(__alpha__)
   /* XXX XXX NEED REAL DMA MAPPING SUPPORT XXX XXX */
   #undef vtophys
   #define vtophys(va)     alpha_XXX_dmamap((vaddr_t)(va))
   #endif
   #elif defined(__FreeBSD__)
   #include <machine/cpufunc.h>            /* for rdtsc proto for clock.h below */
   #include <machine/clock.h>              /* for DELAY */
   #include <dev/en/midwayreg.h>
   #include <dev/en/midwayvar.h>
   #include <vm/pmap.h>                    /* for vtophys proto */
   
   /*
    * 2.1.x does not have if_softc.   detect this by seeing if IFF_NOTRAILERS
    * is defined, as per kjc.
    */
   #ifdef IFF_NOTRAILERS
   #define MISSING_IF_SOFTC
   #else
   #define IFF_NOTRAILERS 0
   #endif
   
   #endif  /* __FreeBSD__ */
   
   #ifdef ATM_PVCEXT
   # ifndef NATM
      /* this is for for __KAME__ */
   #  include <netinet/in.h>
   # endif
   # if defined (__KAME__) && defined(INET6)
   #  include <netinet6/in6_ifattach.h>
   # endif
   #endif /*ATM_PVCEXT*/
   
   #include "bpfilter.h"
   #if NBPFILTER > 0
   #include <net/bpf.h>
   #ifdef __FreeBSD__
   #define BPFATTACH(ifp, dlt, hlen)       bpfattach((ifp), (dlt), (hlen))
   #define BPF_MTAP(ifp, m)                bpf_mtap((ifp), (m))
   #else
   #define BPFATTACH(ifp, dlt, hlen)       bpfattach(&(ifp)->if_bpf, (ifp), (dlt), (hlen))
   #define BPF_MTAP(ifp, m)                bpf_mtap((ifp)->if_bpf, (m))
   #endif
   #endif /* NBPFILTER > 0 */
   
   /*
    * params
    */
   
   #ifndef EN_TXHIWAT
   #define EN_TXHIWAT      (64*1024)       /* max 64 KB waiting to be DMAd out */
   #endif
   
   #ifndef EN_MINDMA
   #define EN_MINDMA       32      /* don't DMA anything less than this (bytes) */
   #endif
   
   #define RX_NONE         0xffff  /* recv VC not in use */
   
   #define EN_OBHDR        ATM_PH_DRIVER7  /* TBD in first mbuf ! */
   #define EN_OBTRL        ATM_PH_DRIVER8  /* PDU trailer in last mbuf ! */
   
   #define ENOTHER_FREE    0x01            /* free rxslot */
   #define ENOTHER_DRAIN   0x02            /* almost free (drain DRQ DMA) */
   #define ENOTHER_RAW     0x04            /* 'raw' access  (aka boodi mode) */
   #define ENOTHER_SWSL    0x08            /* in software service list */
   
   int en_dma = EN_DMA;                    /* use DMA (switch off for dbg) */
   
   /*
    * autoconfig attachments
    */
   
   extern struct cfdriver en_cd;
   
   /*
    * local structures
    */
   
   /*
    * params to en_txlaunch() function
    */
   
   struct en_launch {
     u_int32_t tbd1;               /* TBD 1 */
     u_int32_t tbd2;               /* TBD 2 */
     u_int32_t pdu1;               /* PDU 1 (aal5) */
     int nodma;                    /* don't use DMA */
     int need;                     /* total space we need (pad out if less data) */
     int mlen;                     /* length of mbuf (for dtq) */
     struct mbuf *t;               /* data */
     u_int32_t aal;                /* aal code */
     u_int32_t atm_vci;            /* vci */
     u_int8_t atm_flags;           /* flags */
   };
   
   
   /*
    * DMA table (index by # of words)
    *
    * plan A: use WMAYBE
    * plan B: avoid WMAYBE
    */
   
   struct en_dmatab {
     u_int8_t bcode;               /* code */
     u_int8_t divshift;            /* byte divisor */
   };
   
   static struct en_dmatab en_dma_planA[] = {
     { 0, 0 },             /* 0 */         { MIDDMA_WORD, 2 },     /* 1 */
     { MIDDMA_2WORD, 3},   /* 2 */         { MIDDMA_4WMAYBE, 2},   /* 3 */
     { MIDDMA_4WORD, 4},   /* 4 */         { MIDDMA_8WMAYBE, 2},   /* 5 */
     { MIDDMA_8WMAYBE, 2}, /* 6 */         { MIDDMA_8WMAYBE, 2},   /* 7 */
     { MIDDMA_8WORD, 5},   /* 8 */         { MIDDMA_16WMAYBE, 2},  /* 9 */
     { MIDDMA_16WMAYBE,2}, /* 10 */        { MIDDMA_16WMAYBE, 2},  /* 11 */
     { MIDDMA_16WMAYBE,2}, /* 12 */        { MIDDMA_16WMAYBE, 2},  /* 13 */
     { MIDDMA_16WMAYBE,2}, /* 14 */        { MIDDMA_16WMAYBE, 2},  /* 15 */
     { MIDDMA_16WORD, 6},  /* 16 */
   };
   
   static struct en_dmatab en_dma_planB[] = {
     { 0, 0 },             /* 0 */         { MIDDMA_WORD, 2},      /* 1 */
     { MIDDMA_2WORD, 3},   /* 2 */         { MIDDMA_WORD, 2},      /* 3 */
     { MIDDMA_4WORD, 4},   /* 4 */         { MIDDMA_WORD, 2},      /* 5 */
     { MIDDMA_2WORD, 3},   /* 6 */         { MIDDMA_WORD, 2},      /* 7 */
     { MIDDMA_8WORD, 5},   /* 8 */         { MIDDMA_WORD, 2},      /* 9 */
     { MIDDMA_2WORD, 3},   /* 10 */        { MIDDMA_WORD, 2},      /* 11 */
     { MIDDMA_4WORD, 4},   /* 12 */        { MIDDMA_WORD, 2},      /* 13 */
     { MIDDMA_2WORD, 3},   /* 14 */        { MIDDMA_WORD, 2},      /* 15 */
     { MIDDMA_16WORD, 6},  /* 16 */
   };
   
   static struct en_dmatab *en_dmaplan = en_dma_planA;
   
   /*
    * prototypes
    */
   
   STATIC INLINE   int en_b2sz(int) __attribute__ ((unused));
   #ifdef EN_DDBHOOK
                   int en_dump(int,int);
                   int en_dumpmem(int,int,int);
   #endif
   STATIC          void en_dmaprobe(struct en_softc *);
   STATIC          int en_dmaprobe_doit(struct en_softc *, u_int8_t *,
                       u_int8_t *, int);
   STATIC INLINE   int en_dqneed(struct en_softc *, caddr_t, u_int,
                       u_int) __attribute__ ((unused));
   STATIC          void en_init(struct en_softc *);
   STATIC          int en_ioctl(struct ifnet *, EN_IOCTL_CMDT, caddr_t);
   STATIC INLINE   int en_k2sz(int) __attribute__ ((unused));
   STATIC          void en_loadvc(struct en_softc *, int);
   STATIC          int en_mfix(struct en_softc *, struct mbuf **,
                       struct mbuf *);
   STATIC INLINE   struct mbuf *en_mget(struct en_softc *, u_int,
                       u_int *) __attribute__ ((unused));
   STATIC INLINE   u_int32_t en_read(struct en_softc *,
                       u_int32_t) __attribute__ ((unused));
   STATIC          int en_rxctl(struct en_softc *, struct atm_pseudoioctl *, int);
   STATIC          void en_txdma(struct en_softc *, int);
   STATIC          void en_txlaunch(struct en_softc *, int, struct en_launch *);
   STATIC          void en_service(struct en_softc *);
   STATIC          void en_start(struct ifnet *);
   STATIC INLINE   int en_sz2b(int) __attribute__ ((unused));
   STATIC INLINE   void en_write(struct en_softc *, u_int32_t,
                       u_int32_t) __attribute__ ((unused));
   
   #ifdef ATM_PVCEXT
   static void rrp_add(struct en_softc *, struct ifnet *);
   static struct ifnet *en_pvcattach(struct ifnet *);
   static int en_txctl(struct en_softc *, int, int, int);
   static int en_pvctx(struct en_softc *, struct pvctxreq *);
   static int en_pvctxget(struct en_softc *, struct pvctxreq *);
   static int en_pcr2txspeed(int);
   static int en_txspeed2pcr(int);
   static struct ifnet *en_vci2ifp(struct en_softc *, int);
   #endif
   
   /*
    * macros/inline
    */
   
   /*
    * raw read/write macros
    */
   
   #define EN_READDAT(SC,R) en_read(SC,R)
   #define EN_WRITEDAT(SC,R,V) en_write(SC,R,V)
   
   /*
    * cooked read/write macros
    */
   
   #define EN_READ(SC,R) ntohl(en_read(SC,R))
   #define EN_WRITE(SC,R,V) en_write(SC,R, htonl(V))
   
   #define EN_WRAPADD(START,STOP,CUR,VAL) { \
           (CUR) = (CUR) + (VAL); \
           if ((CUR) >= (STOP)) \
                   (CUR) = (START) + ((CUR) - (STOP)); \
           }
   
   #define WORD_IDX(START, X) (((X) - (START)) / sizeof(u_int32_t))
   
   /* we store sc->dtq and sc->drq data in the following format... */
   #define EN_DQ_MK(SLOT,LEN) (((SLOT) << 20)|(LEN)|(0x80000))
                                           /* the 0x80000 ensures we != 0 */
   #define EN_DQ_SLOT(X) ((X) >> 20)
   #define EN_DQ_LEN(X) ((X) & 0x3ffff)
   
   /* format of DTQ/DRQ word 1 differs between ENI and ADP */
   #if defined(MIDWAY_ENIONLY)
   
   #define MID_MK_TXQ(SC,CNT,CHAN,END,BCODE) \
           EN_WRITE((SC), (SC)->dtq_us, \
                   MID_MK_TXQ_ENI((CNT), (CHAN), (END), (BCODE)));
   
   #define MID_MK_RXQ(SC,CNT,VCI,END,BCODE) \
           EN_WRITE((SC), (SC)->drq_us, \
                   MID_MK_RXQ_ENI((CNT), (VCI), (END), (BCODE)));
   
   #elif defined(MIDWAY_ADPONLY)
   
   #define MID_MK_TXQ(SC,CNT,CHAN,END,JK) \
           EN_WRITE((SC), (SC)->dtq_us, \
                   MID_MK_TXQ_ADP((CNT), (CHAN), (END), (JK)));
   
   #define MID_MK_RXQ(SC,CNT,VCI,END,JK) \
           EN_WRITE((SC), (SC)->drq_us, \
                   MID_MK_RXQ_ADP((CNT), (VCI), (END), (JK)));
   
   #else
   
   #define MID_MK_TXQ(SC,CNT,CHAN,END,JK_OR_BCODE) { \
           if ((SC)->is_adaptec) \
             EN_WRITE((SC), (SC)->dtq_us, \
                     MID_MK_TXQ_ADP((CNT), (CHAN), (END), (JK_OR_BCODE))); \
           else \
             EN_WRITE((SC), (SC)->dtq_us, \
                     MID_MK_TXQ_ENI((CNT), (CHAN), (END), (JK_OR_BCODE))); \
           }
   
   #define MID_MK_RXQ(SC,CNT,VCI,END,JK_OR_BCODE) { \
           if ((SC)->is_adaptec) \
             EN_WRITE((SC), (SC)->drq_us, \
                     MID_MK_RXQ_ADP((CNT), (VCI), (END), (JK_OR_BCODE))); \
           else \
             EN_WRITE((SC), (SC)->drq_us, \
                      MID_MK_RXQ_ENI((CNT), (VCI), (END), (JK_OR_BCODE))); \
           }
   
   #endif
   
   /* add an item to the DTQ */
   #define EN_DTQADD(SC,CNT,CHAN,JK_OR_BCODE,ADDR,LEN,END) { \
           if (END) \
             (SC)->dtq[MID_DTQ_A2REG((SC)->dtq_us)] = EN_DQ_MK(CHAN,LEN); \
           MID_MK_TXQ(SC,CNT,CHAN,END,JK_OR_BCODE); \
           (SC)->dtq_us += 4; \
           EN_WRITE((SC), (SC)->dtq_us, (ADDR)); \
           EN_WRAPADD(MID_DTQOFF, MID_DTQEND, (SC)->dtq_us, 4); \
           (SC)->dtq_free--; \
           if (END) \
             EN_WRITE((SC), MID_DMA_WRTX, MID_DTQ_A2REG((SC)->dtq_us)); \
   }
   
   /* DRQ add macro */
   #define EN_DRQADD(SC,CNT,VCI,JK_OR_BCODE,ADDR,LEN,SLOT,END) { \
           if (END) \
             (SC)->drq[MID_DRQ_A2REG((SC)->drq_us)] = EN_DQ_MK(SLOT,LEN); \
           MID_MK_RXQ(SC,CNT,VCI,END,JK_OR_BCODE); \
           (SC)->drq_us += 4; \
           EN_WRITE((SC), (SC)->drq_us, (ADDR)); \
           EN_WRAPADD(MID_DRQOFF, MID_DRQEND, (SC)->drq_us, 4); \
           (SC)->drq_free--; \
           if (END) \
             EN_WRITE((SC), MID_DMA_WRRX, MID_DRQ_A2REG((SC)->drq_us)); \
   }
   
   /*
    * the driver code
    *
    * the code is arranged in a specific way:
    * [1] short/inline functions
    * [2] autoconfig stuff
    * [3] ioctl stuff
    * [4] reset -> init -> transmit -> intr -> receive functions
    *
    */
   
   /***********************************************************************/
   
   /*
    * en_read: read a word from the card.   this is the only function
    * that reads from the card.
    */
   
   STATIC INLINE u_int32_t en_read(sc, r)
   
   struct en_softc *sc;
   u_int32_t r;
   
   {
   
   #ifdef EN_DEBUG_RANGE
     if (r > MID_MAXOFF || (r % 4))
       panic("en_read out of range, r=0x%x", r);
   #endif
   
     return(bus_space_read_4(sc->en_memt, sc->en_base, r));
   }
   
   /*
    * en_write: write a word to the card.   this is the only function that
    * writes to the card.
    */
   
   STATIC INLINE void en_write(sc, r, v)
   
   struct en_softc *sc;
   u_int32_t r, v;
   
   {
   #ifdef EN_DEBUG_RANGE
     if (r > MID_MAXOFF || (r % 4))
       panic("en_write out of range, r=0x%x", r);
   #endif
   
     bus_space_write_4(sc->en_memt, sc->en_base, r, v);
   }
   
   /*
    * en_k2sz: convert KBytes to a size parameter (a log2)
    */
   
   STATIC INLINE int en_k2sz(k)
   
   int k;
   
   {
     switch(k) {
       case 1:   return(0);
       case 2:   return(1);
       case 4:   return(2);
       case 8:   return(3);
       case 16:  return(4);
       case 32:  return(5);
       case 64:  return(6);
       case 128: return(7);
       default: panic("en_k2sz");
     }
     return(0);
   }
   #define en_log2(X) en_k2sz(X)
   
   
   /*
    * en_b2sz: convert a DMA burst code to its byte size
    */
   
   STATIC INLINE int en_b2sz(b)
   
   int b;
   
   {
     switch (b) {
       case MIDDMA_WORD:   return(1*4);
       case MIDDMA_2WMAYBE:
       case MIDDMA_2WORD:  return(2*4);
       case MIDDMA_4WMAYBE:
       case MIDDMA_4WORD:  return(4*4);
       case MIDDMA_8WMAYBE:
       case MIDDMA_8WORD:  return(8*4);
       case MIDDMA_16WMAYBE:
       case MIDDMA_16WORD: return(16*4);
       default: panic("en_b2sz");
     }
     return(0);
   }
   
   
   /*
    * en_sz2b: convert a burst size (bytes) to DMA burst code
    */
   
   STATIC INLINE int en_sz2b(sz)
   
   int sz;
   
   {
     switch (sz) {
       case 1*4:  return(MIDDMA_WORD);
       case 2*4:  return(MIDDMA_2WORD);
       case 4*4:  return(MIDDMA_4WORD);
       case 8*4:  return(MIDDMA_8WORD);
       case 16*4: return(MIDDMA_16WORD);
       default: panic("en_sz2b");
     }
     return(0);
   }
   
   
   /*
    * en_dqneed: calculate number of DTQ/DRQ's needed for a buffer
    */
   
   STATIC INLINE int en_dqneed(sc, data, len, tx)
   
   struct en_softc *sc;
   caddr_t data;
   u_int len, tx;
   
   {
     int result, needalign, sz;
   
   #if !defined(MIDWAY_ENIONLY)
   #if !defined(MIDWAY_ADPONLY)
       if (sc->is_adaptec)
   #endif /* !MIDWAY_ADPONLY */
         return(1);        /* adaptec can DMA anything in one go */
   #endif
   
   #if !defined(MIDWAY_ADPONLY)
       result = 0;
       if (len < EN_MINDMA) {
         if (!tx)                  /* XXX: conservative */
           return(1);              /* will copy/DMA_JK */
       }
   
       if (tx) {                   /* byte burst? */
         needalign = (((unsigned long) data) % sizeof(u_int32_t));
         if (needalign) {
           result++;
           sz = min(len, sizeof(u_int32_t) - needalign);
           len -= sz;
           data += sz;
         }
       }
   
       if (sc->alburst && len) {
         needalign = (((unsigned long) data) & sc->bestburstmask);
         if (needalign) {
           result++;               /* alburst */
           sz = min(len, sc->bestburstlen - needalign);
           len -= sz;
         }
       }
   
       if (len >= sc->bestburstlen) {
         sz = len / sc->bestburstlen;
         sz = sz * sc->bestburstlen;
         len -= sz;
         result++;                 /* best shot */
       }
   
       if (len) {
         result++;                 /* clean up */
         if (tx && (len % sizeof(u_int32_t)) != 0)
           result++;               /* byte cleanup */
       }
   
       return(result);
   #endif  /* !MIDWAY_ADPONLY */
   }
   
   
   /*
    * en_mget: get an mbuf chain that can hold totlen bytes and return it
    * (for recv)   [based on am7990_get from if_le and ieget from if_ie]
    * after this call the sum of all the m_len's in the chain will be totlen.
    */
   
   STATIC INLINE struct mbuf *en_mget(sc, totlen, drqneed)
   
   struct en_softc *sc;
   u_int totlen, *drqneed;
   
   {
     struct mbuf *m;
     struct mbuf *top, **mp;
     *drqneed = 0;
   
     MGETHDR(m, M_DONTWAIT, MT_DATA);
     if (m == NULL)
       return(NULL);
     m->m_pkthdr.rcvif = &sc->enif;
     m->m_pkthdr.len = totlen;
     m->m_len = MHLEN;
     top = NULL;
     mp = &top;
   
     /* if (top != NULL) then we've already got 1 mbuf on the chain */
     while (totlen > 0) {
       if (top) {
         MGET(m, M_DONTWAIT, MT_DATA);
         if (!m) {
           m_freem(top);
           return(NULL);   /* out of mbufs */
         }
         m->m_len = MLEN;
       }
       if (totlen >= MINCLSIZE) {
         MCLGET(m, M_DONTWAIT);
         if ((m->m_flags & M_EXT) == 0) {
           m_free(m);
           m_freem(top);
           return(NULL);   /* out of mbuf clusters */
         }
         m->m_len = MCLBYTES;
       }
       m->m_len = min(totlen, m->m_len);
       totlen -= m->m_len;
       *mp = m;
       mp = &m->m_next;
   
       *drqneed += en_dqneed(sc, m->m_data, m->m_len, 0);
   
     }
     return(top);
   }
   
   /***********************************************************************/
   
   /*
    * autoconfig stuff
    */
   
   void en_attach(sc)
   
   struct en_softc *sc;
   
   {
     struct ifnet *ifp = &sc->enif;
     int sz;
     u_int32_t reg, lcv, check, ptr, sav, midvloc;
   
     /*
      * probe card to determine memory size.   the stupid ENI card always
      * reports to PCI that it needs 4MB of space (2MB regs and 2MB RAM).
      * if it has less than 2MB RAM the addresses wrap in the RAM address space.
      * (i.e. on a 512KB card addresses 0x3ffffc, 0x37fffc, and 0x2ffffc
      * are aliases for 0x27fffc  [note that RAM starts at offset 0x200000]).
      */
   
     if (sc->en_busreset)
       sc->en_busreset(sc);
     EN_WRITE(sc, MID_RESID, 0x0); /* reset card before touching RAM */
     for (lcv = MID_PROBEOFF; lcv <= MID_MAXOFF ; lcv += MID_PROBSIZE) {
       EN_WRITE(sc, lcv, lcv);     /* data[address] = address */
       for (check = MID_PROBEOFF ; check < lcv ; check += MID_PROBSIZE) {
         reg = EN_READ(sc, check);
         if (reg != check) {               /* found an alias! */
           goto done_probe;                /* and quit */
         }
       }
     }
   done_probe:
     lcv -= MID_PROBSIZE;                  /* take one step back */
     sc->en_obmemsz = (lcv + 4) - MID_RAMOFF;
   
     /*
      * determine the largest DMA burst supported
      */
   
     en_dmaprobe(sc);
   
     /*
      * "hello world"
      */
   
     if (sc->en_busreset)
       sc->en_busreset(sc);
     EN_WRITE(sc, MID_RESID, 0x0);         /* reset */
     for (lcv = MID_RAMOFF ; lcv < MID_RAMOFF + sc->en_obmemsz ; lcv += 4)
       EN_WRITE(sc, lcv, 0);       /* zero memory */
   
     reg = EN_READ(sc, MID_RESID);
   
     aprint_normal(
         "%s: ATM midway v%d, board IDs %d.%d, %s%s%s, %ldKB on-board RAM\n",
           sc->sc_dev.dv_xname, MID_VER(reg), MID_MID(reg), MID_DID(reg),
           (MID_IS_SABRE(reg)) ? "sabre controller, " : "",
           (MID_IS_SUNI(reg)) ? "SUNI" : "Utopia",
           (!MID_IS_SUNI(reg) && MID_IS_UPIPE(reg)) ? " (pipelined)" : "",
           (u_long)sc->en_obmemsz / 1024);
   
     if (sc->is_adaptec) {
       if (sc->bestburstlen == 64 && sc->alburst == 0)
         aprint_normal("%s: passed 64 byte DMA test\n", sc->sc_dev.dv_xname);
       else
         aprint_error("%s: FAILED DMA TEST: burst=%d, alburst=%d\n",
               sc->sc_dev.dv_xname, sc->bestburstlen, sc->alburst);
     } else {
       aprint_normal("%s: maximum DMA burst length = %d bytes%s\n",
             sc->sc_dev.dv_xname,
             sc->bestburstlen, (sc->alburst) ? " (must align)" : "");
     }
   
   #if 0           /* WMAYBE doesn't work, don't complain about it */
     /* check if en_dmaprobe disabled wmaybe */
     if (en_dmaplan == en_dma_planB)
       aprint_normal("%s: note: WMAYBE DMA has been disabled\n",
           sc->sc_dev.dv_xname);
   #endif
   
     /*
      * link into network subsystem and prepare card
      */
   
   #if defined(__NetBSD__) || defined(__OpenBSD__)
     strcpy(sc->enif.if_xname, sc->sc_dev.dv_xname);
   #endif
   #if !defined(MISSING_IF_SOFTC)
     sc->enif.if_softc = sc;
   #endif
     ifp->if_flags = IFF_SIMPLEX|IFF_NOTRAILERS;
     ifp->if_ioctl = en_ioctl;
     ifp->if_output = atm_output;
     ifp->if_start = en_start;
     IFQ_SET_READY(&ifp->if_snd);
   
     /*
      * init softc
      */
   
     for (lcv = 0 ; lcv < MID_N_VC ; lcv++) {
       sc->rxvc2slot[lcv] = RX_NONE;
       sc->txspeed[lcv] = 0;       /* full */
       sc->txvc2slot[lcv] = 0;     /* full speed == slot 0 */
     }
   
     sz = sc->en_obmemsz - (MID_BUFOFF - MID_RAMOFF);
     ptr = sav = MID_BUFOFF;
     ptr = roundup(ptr, EN_TXSZ * 1024);   /* align */
     sz = sz - (ptr - sav);
     if (EN_TXSZ*1024 * EN_NTX > sz) {
       aprint_error("%s: EN_NTX/EN_TXSZ too big\n", sc->sc_dev.dv_xname);
       return;
     }
     for (lcv = 0 ; lcv < EN_NTX ; lcv++) {
       sc->txslot[lcv].mbsize = 0;
       sc->txslot[lcv].start = ptr;
       ptr += (EN_TXSZ * 1024);
       sz -= (EN_TXSZ * 1024);
       sc->txslot[lcv].stop = ptr;
       sc->txslot[lcv].nref = 0;
   #ifdef ATM_PVCEXT
       sc->txrrp = NULL;
   #endif
       memset(&sc->txslot[lcv].indma, 0, sizeof(sc->txslot[lcv].indma));
       memset(&sc->txslot[lcv].q, 0, sizeof(sc->txslot[lcv].q));
   #ifdef EN_DEBUG
       aprint_debug("%s: tx%d: start 0x%x, stop 0x%x\n", sc->sc_dev.dv_xname, lcv,
                   sc->txslot[lcv].start, sc->txslot[lcv].stop);
   #endif
     }
   
     sav = ptr;
     ptr = roundup(ptr, EN_RXSZ * 1024);   /* align */
     sz = sz - (ptr - sav);
     sc->en_nrx = sz / (EN_RXSZ * 1024);
     if (sc->en_nrx <= 0) {
       aprint_error("%s: EN_NTX/EN_TXSZ/EN_RXSZ too big\n", sc->sc_dev.dv_xname);
       return;
     }
   
     /*
      * ensure that there is always one VC slot on the service list free
      * so that we can tell the difference between a full and empty list.
      */
     if (sc->en_nrx >= MID_N_VC)
       sc->en_nrx = MID_N_VC - 1;
   
     for (lcv = 0 ; lcv < sc->en_nrx ; lcv++) {
       sc->rxslot[lcv].rxhand = NULL;
       sc->rxslot[lcv].oth_flags = ENOTHER_FREE;
       memset(&sc->rxslot[lcv].indma, 0, sizeof(sc->rxslot[lcv].indma));
       memset(&sc->rxslot[lcv].q, 0, sizeof(sc->rxslot[lcv].q));
       midvloc = sc->rxslot[lcv].start = ptr;
       ptr += (EN_RXSZ * 1024);
       sz -= (EN_RXSZ * 1024);
       sc->rxslot[lcv].stop = ptr;
       midvloc = midvloc - MID_RAMOFF;
       midvloc = (midvloc & ~((EN_RXSZ*1024) - 1)) >> 2; /* mask, cvt to words */
       midvloc = midvloc >> MIDV_LOCTOPSHFT;  /* we only want the top 11 bits */
       midvloc = (midvloc & MIDV_LOCMASK) << MIDV_LOCSHIFT;
       sc->rxslot[lcv].mode = midvloc |
           (en_k2sz(EN_RXSZ) << MIDV_SZSHIFT) | MIDV_TRASH;
   
   #ifdef EN_DEBUG
       aprint_debug("%s: rx%d: start 0x%x, stop 0x%x, mode 0x%x\n",
           sc->sc_dev.dv_xname,
           lcv, sc->rxslot[lcv].start, sc->rxslot[lcv].stop, sc->rxslot[lcv].mode);
   #endif
     }
   
   #ifdef EN_STAT
     sc->vtrash = sc->otrash = sc->mfix = sc->txmbovr = sc->dmaovr = 0;
     sc->txoutspace = sc->txdtqout = sc->launch = sc->lheader = sc->ltail = 0;
     sc->hwpull = sc->swadd = sc->rxqnotus = sc->rxqus = sc->rxoutboth = 0;
     sc->rxdrqout = sc->ttrash = sc->rxmbufout = sc->mfixfail = 0;
     sc->headbyte = sc->tailbyte = sc->tailflush = 0;
   #endif
     sc->need_drqs = sc->need_dtqs = 0;
   
     aprint_normal(
           "%s: %d %dKB receive buffers, %d %dKB transmit buffers allocated\n",
           sc->sc_dev.dv_xname, sc->en_nrx, EN_RXSZ, EN_NTX, EN_TXSZ);
   
     aprint_normal("%s: End Station Identifier (mac address) %s\n",
           sc->sc_dev.dv_xname, ether_sprintf(sc->macaddr));
   
     /*
      * final commit
      */
   
     if_attach(ifp);
     atm_ifattach(ifp);
   
   #ifdef ATM_PVCEXT
     rrp_add(sc, ifp);
   #endif
   }
   
   
   /*
    * en_dmaprobe: helper function for en_attach.
    *
    * see how the card handles DMA by running a few DMA tests.   we need
    * to figure out the largest number of bytes we can DMA in one burst
    * ("bestburstlen"), and if the starting address for a burst needs to
    * be aligned on any sort of boundary or not ("alburst").
    *
    * typical findings:
    * sparc1: bestburstlen=4, alburst=0 (ick, broken DMA!)
    * sparc2: bestburstlen=64, alburst=1
    * p166:   bestburstlen=64, alburst=0
    */
   
   STATIC void en_dmaprobe(sc)
   
   struct en_softc *sc;
   
   {
     u_int32_t srcbuf[64], dstbuf[64];
     u_int8_t *sp, *dp;
     int bestalgn, bestnotalgn, lcv, try, fail;
   
     sc->alburst = 0;
   
     sp = (u_int8_t *) srcbuf;
     while ((((unsigned long) sp) % MIDDMA_MAXBURST) != 0)
       sp += 4;
     dp = (u_int8_t *) dstbuf;
     while ((((unsigned long) dp) % MIDDMA_MAXBURST) != 0)
       dp += 4;
   
     bestalgn = bestnotalgn = en_dmaprobe_doit(sc, sp, dp, 0);
   
     for (lcv = 4 ; lcv < MIDDMA_MAXBURST ; lcv += 4) {
       try = en_dmaprobe_doit(sc, sp+lcv, dp+lcv, 0);
       if (try < bestnotalgn)
         bestnotalgn = try;
     }
   
     if (bestalgn != bestnotalgn)          /* need bursts aligned */
       sc->alburst = 1;
   
     sc->bestburstlen = bestalgn;
     sc->bestburstshift = en_log2(bestalgn);
     sc->bestburstmask = sc->bestburstlen - 1; /* must be power of 2 */
     sc->bestburstcode = en_sz2b(bestalgn);
   
     if (sc->bestburstlen <= 2*sizeof(u_int32_t))
       return;                             /* won't be using WMAYBE */
   
     /*
      * adaptec does not have (or need) wmaybe.   do not bother testing
      * for it.
      */
     if (sc->is_adaptec) {
       /* XXX, actually don't need a DMA plan: adaptec is smarter than that */
       en_dmaplan = en_dma_planB;
       return;
     }
   
     /*
      * test that WMAYBE DMA works like we think it should
      * (i.e. no alignment restrictions on host address other than alburst)
      */
   
     try = sc->bestburstlen - 4;
     fail = 0;
     fail += en_dmaprobe_doit(sc, sp, dp, try);
     for (lcv = 4 ; lcv < sc->bestburstlen ; lcv += 4) {
       fail += en_dmaprobe_doit(sc, sp+lcv, dp+lcv, try);
       if (sc->alburst)
         try -= 4;
     }
     if (EN_NOWMAYBE || fail) {
       if (fail)
        printf("%s: WARNING: WMAYBE DMA test failed %d time(s)\n",
          sc->sc_dev.dv_xname, fail);
      en_dmaplan = en_dma_planB;          /* fall back to plan B */
    }
  
  }
  
  
  /*
   * en_dmaprobe_doit: do actual testing
   */
  
  int
  en_dmaprobe_doit(sc, sp, dp, wmtry)
  
  struct en_softc *sc;
  u_int8_t *sp, *dp;
  int wmtry;
  
  {
    int lcv, retval = 4, cnt, count;
    u_int32_t reg, bcode, midvloc;
  
    /*
     * set up a 1k buffer at MID_BUFOFF
     */
  
    if (sc->en_busreset)
      sc->en_busreset(sc);
    EN_WRITE(sc, MID_RESID, 0x0); /* reset card before touching RAM */
  
    midvloc = ((MID_BUFOFF - MID_RAMOFF) / sizeof(u_int32_t)) >> MIDV_LOCTOPSHFT;
    EN_WRITE(sc, MIDX_PLACE(0), MIDX_MKPLACE(en_k2sz(1), midvloc));
    EN_WRITE(sc, MID_VC(0), (midvloc << MIDV_LOCSHIFT)
                  | (en_k2sz(1) << MIDV_SZSHIFT) | MIDV_TRASH);
    EN_WRITE(sc, MID_DST_RP(0), 0);
    EN_WRITE(sc, MID_WP_ST_CNT(0), 0);
  
    for (lcv = 0 ; lcv < 68 ; lcv++)              /* set up sample data */
      sp[lcv] = lcv+1;
    EN_WRITE(sc, MID_MAST_CSR, MID_MCSR_ENDMA);   /* enable DMA (only) */
  
    sc->drq_chip = MID_DRQ_REG2A(EN_READ(sc, MID_DMA_RDRX));
    sc->dtq_chip = MID_DTQ_REG2A(EN_READ(sc, MID_DMA_RDTX));
  
    /*
     * try it now . . .  DMA it out, then DMA it back in and compare
     *
     * note: in order to get the DMA stuff to reverse directions it wants
     * the "end" flag set!   since we are not DMA'ing valid data we may
     * get an ident mismatch interrupt (which we will ignore).
     *
     * note: we've got two different tests rolled up in the same loop
     * if (wmtry)
     *   then we are doing a wmaybe test and wmtry is a byte count
     *   else we are doing a burst test
     */
  
    for (lcv = 8 ; lcv <= MIDDMA_MAXBURST ; lcv = lcv * 2) {
  
      /* zero SRAM and dest buffer */
      for (cnt = 0 ; cnt < 1024; cnt += 4)
        EN_WRITE(sc, MID_BUFOFF+cnt, 0);  /* zero memory */
      for (cnt = 0 ; cnt < 68  ; cnt++)
        dp[cnt] = 0;
  
      if (wmtry) {
        count = (sc->bestburstlen - sizeof(u_int32_t)) / sizeof(u_int32_t);
        bcode = en_dmaplan[count].bcode;
        count = wmtry >> en_dmaplan[count].divshift;
      } else {
        bcode = en_sz2b(lcv);
        count = 1;
      }
      if (sc->is_adaptec)
        EN_WRITE(sc, sc->dtq_chip, MID_MK_TXQ_ADP(lcv, 0, MID_DMA_END, 0));
      else
        EN_WRITE(sc, sc->dtq_chip, MID_MK_TXQ_ENI(count, 0, MID_DMA_END, bcode));
      EN_WRITE(sc, sc->dtq_chip+4, vtophys((vaddr_t)sp));
      EN_WRITE(sc, MID_DMA_WRTX, MID_DTQ_A2REG(sc->dtq_chip+8));
      cnt = 1000;
      while (EN_READ(sc, MID_DMA_RDTX) == MID_DTQ_A2REG(sc->dtq_chip)) {
        DELAY(1);
        cnt--;
        if (cnt == 0) {
          printf("%s: unexpected timeout in tx DMA test\n", sc->sc_dev.dv_xname);
          return(retval);         /* timeout, give up */
        }
      }
      EN_WRAPADD(MID_DTQOFF, MID_DTQEND, sc->dtq_chip, 8);
      reg = EN_READ(sc, MID_INTACK);
      if ((reg & MID_INT_DMA_TX) != MID_INT_DMA_TX) {
        printf("%s: unexpected status in tx DMA test: 0x%x\n",
                  sc->sc_dev.dv_xname, reg);
        return(retval);
      }
      EN_WRITE(sc, MID_MAST_CSR, MID_MCSR_ENDMA);   /* re-enable DMA (only) */
  
      /* "return to sender..."  address is known ... */
  
      if (sc->is_adaptec)
        EN_WRITE(sc, sc->drq_chip, MID_MK_RXQ_ADP(lcv, 0, MID_DMA_END, 0));
      else
        EN_WRITE(sc, sc->drq_chip, MID_MK_RXQ_ENI(count, 0, MID_DMA_END, bcode));
      EN_WRITE(sc, sc->drq_chip+4, vtophys((vaddr_t)dp));
      EN_WRITE(sc, MID_DMA_WRRX, MID_DRQ_A2REG(sc->drq_chip+8));
      cnt = 1000;
      while (EN_READ(sc, MID_DMA_RDRX) == MID_DRQ_A2REG(sc->drq_chip)) {
        DELAY(1);
        cnt--;
        if (cnt == 0) {
          printf("%s: unexpected timeout in rx DMA test\n", sc->sc_dev.dv_xname);
          return(retval);         /* timeout, give up */
        }
      }
      EN_WRAPADD(MID_DRQOFF, MID_DRQEND, sc->drq_chip, 8);
      reg = EN_READ(sc, MID_INTACK);
      if ((reg & MID_INT_DMA_RX) != MID_INT_DMA_RX) {
        printf("%s: unexpected status in rx DMA test: 0x%x\n",
                  sc->sc_dev.dv_xname, reg);
        return(retval);
      }
      EN_WRITE(sc, MID_MAST_CSR, MID_MCSR_ENDMA);   /* re-enable DMA (only) */
  
      if (wmtry) {
        return(memcmp(sp, dp, wmtry));  /* wmtry always exits here, no looping */
      }
  
      if (memcmp(sp, dp, lcv))
        return(retval);           /* failed, use last value */
  
      retval = lcv;
  
    }
    return(retval);               /* studly 64 byte DMA present!  oh baby!! */
  }
  
  /***********************************************************************/
  
  /*
   * en_ioctl: handle ioctl requests
   *
   * NOTE: if you add an ioctl to set txspeed, you should choose a new
   * TX channel/slot.   Choose the one with the lowest sc->txslot[slot].nref
   * value, subtract one from sc->txslot[0].nref, add one to the
   * sc->txslot[slot].nref, set sc->txvc2slot[vci] = slot, and then set
   * txspeed[vci].
   */
  
  STATIC int en_ioctl(ifp, cmd, data)
  
  struct ifnet *ifp;
  EN_IOCTL_CMDT cmd;
  caddr_t data;
  
  {
  #ifdef MISSING_IF_SOFTC
      struct en_softc *sc = (struct en_softc *) en_cd.cd_devs[ifp->if_unit];
  #else
      struct en_softc *sc = (struct en_softc *) ifp->if_softc;
  #endif
      struct ifaddr *ifa = (struct ifaddr *) data;
      struct ifreq *ifr = (struct ifreq *) data;
      struct atm_pseudoioctl *api = (struct atm_pseudoioctl *)data;
  #ifdef NATM
      struct atm_rawioctl *ario = (struct atm_rawioctl *)data;
      int slot;
  #endif
      int s, error = 0;
  
      s = splnet();
  
      switch (cmd) {
          case SIOCATMENA:                /* enable circuit for recv */
                  error = en_rxctl(sc, api, 1);
                  break;
  
          case SIOCATMDIS:                /* disable circuit for recv */
                  error = en_rxctl(sc, api, 0);
                  break;
  
  #ifdef NATM
          case SIOCXRAWATM:
                  if ((slot = sc->rxvc2slot[ario->npcb->npcb_vci]) == RX_NONE) {
                          error = EINVAL;
                          break;
                  }
                  if (ario->rawvalue > EN_RXSZ*1024)
                          ario->rawvalue = EN_RXSZ*1024;
                  if (ario->rawvalue) {
                          sc->rxslot[slot].oth_flags |= ENOTHER_RAW;
                          sc->rxslot[slot].raw_threshold = ario->rawvalue;
                  } else {
                          sc->rxslot[slot].oth_flags &= (~ENOTHER_RAW);
                          sc->rxslot[slot].raw_threshold = 0;
                  }
  #ifdef EN_DEBUG
                  printf("%s: rxvci%d: turn %s raw (boodi) mode\n",
                          sc->sc_dev.dv_xname, ario->npcb->npcb_vci,
                          (ario->rawvalue) ? "on" : "off");
  #endif
                  break;
  #endif
          case SIOCSIFADDR:
  #ifdef INET6
          case SIOCSIFADDR_IN6:
  #endif
                  ifp->if_flags |= IFF_UP;
                  switch (ifa->ifa_addr->sa_family) {
  #ifdef INET
                  case AF_INET:
                          en_reset(sc);
                          en_init(sc);
                          ifa->ifa_rtrequest = atm_rtrequest; /* ??? */
                          break;
  #endif
  #ifdef INET6
                  case AF_INET6:
                          en_reset(sc);
                          en_init(sc);
                          ifa->ifa_rtrequest = atm_rtrequest; /* ??? */
                          break;
  #endif
                  default:
                          /* what to do if not INET? */
                          en_reset(sc);
                          en_init(sc);
                          break;
                  }
                  break;
  
          case SIOCGIFADDR:
                  error = EINVAL;
                  break;
  
          case SIOCSIFFLAGS:
  #ifdef ATM_PVCEXT
                  /* point-2-point pvc is allowed to change if_flags */
                  if (((ifp->if_flags & IFF_UP) && !(ifp->if_flags & IFF_RUNNING))
                  ||  (!(ifp->if_flags & IFF_UP) && (ifp->if_flags & IFF_RUNNING))) {
                          en_reset(sc);
                          en_init(sc);
                  }
  #else
                  error = EINVAL;
  #endif
                  break;
  
  #if defined(SIOCSIFMTU)         /* ??? copied from if_de */
  #if !defined(ifr_mtu)
  #define ifr_mtu ifr_metric
  #endif
          case SIOCSIFMTU:
              /*
               * Set the interface MTU.
               */
  #ifdef notsure
              if (ifr->ifr_mtu > ATMMTU) {
                  error = EINVAL;
                  break;
              }
  #endif
              ifp->if_mtu = ifr->ifr_mtu;
                  /* XXXCDC: do we really need to reset on MTU size change? */
              en_reset(sc);
              en_init(sc);
              break;
  #endif /* SIOCSIFMTU */
  
  #ifdef ATM_PVCEXT
          case SIOCADDMULTI:
          case SIOCDELMULTI:
                  if (ifp == &sc->enif || ifr == 0) {
                          error = EAFNOSUPPORT;   /* XXX */
                          break;
                  }
                  switch (ifr->ifr_addr.sa_family) {
  #ifdef INET
                  case AF_INET:
                          break;
  #endif
  #ifdef INET6
                  case AF_INET6:
                          break;
  #endif
                  default:
                          error = EAFNOSUPPORT;
                          break;
                  }
                  break;
  
          case SIOCGPVCSIF:
                  if (ifp != &sc->enif) {
  #ifdef __NetBSD__
                    strlcpy(ifr->ifr_name, sc->enif.if_xname,
                        sizeof(ifr->ifr_name));
  #else
                    snprintf(ifr->ifr_name, sizeof(ifr->ifr_name), "%s%d",
                            sc->enif.if_name, sc->enif.if_unit);
  #endif
                  }
                  else
                    error = EINVAL;
                  break;
  
          case SIOCSPVCSIF:
                  if (ifp == &sc->enif) {
                    struct ifnet *sifp;
  
                    if ((error = suser(curproc->p_ucred, &curproc->p_acflag)) != 0)
                      break;
  
                    if ((sifp = en_pvcattach(ifp)) != NULL) {
  #ifdef __NetBSD__
                      strlcpy(ifr->ifr_name, sifp->if_xname,
                          sizeof(ifr->ifr_name));
  #else
                      snprintf(ifr->ifr_name, sizeof(ifr->ifr_name), "%s%d",
                          sifp->if_name, sifp->if_unit);
  #endif
  #if defined(__KAME__) && defined(INET6)
                      /* get EUI64 for PVC, from ATM hardware interface */
                      in6_ifattach(sifp, ifp);
  #endif
                    }
                    else
                      error = ENOMEM;
                  }
                  else
                    error = EINVAL;
                  break;
  
          case SIOCGPVCTX:
                  error = en_pvctxget(sc, (struct pvctxreq *)data);
                  break;
  
          case SIOCSPVCTX:
                  if ((error = suser(curproc->p_ucred, &curproc->p_acflag)) == 0)
                          error = en_pvctx(sc, (struct pvctxreq *)data);
                  break;
  
  #endif /* ATM_PVCEXT */
  
          default:
              error = EINVAL;
              break;
      }
      splx(s);
      return error;
  }
  
  
  /*
   * en_rxctl: turn on and off VCs for recv.
   */
  
  STATIC int en_rxctl(sc, pi, on)
  
  struct en_softc *sc;
  struct atm_pseudoioctl *pi;
  int on;
  
  {
    u_int s, vci, flags, slot;
    u_int32_t oldmode, newmode;
  
    vci = ATM_PH_VCI(&pi->aph);
    flags = ATM_PH_FLAGS(&pi->aph);
  
  #ifdef EN_DEBUG
    printf("%s: %s vpi=%d, vci=%d, flags=%d\n", sc->sc_dev.dv_xname,
          (on) ? "enable" : "disable", ATM_PH_VPI(&pi->aph), vci, flags);
  #endif
  
    if (ATM_PH_VPI(&pi->aph) || vci >= MID_N_VC)
      return(EINVAL);
  
    /*
     * turn on VCI!
     */
  
    if (on) {
      if (sc->rxvc2slot[vci] != RX_NONE)
        return(EINVAL);
      for (slot = 0 ; slot < sc->en_nrx ; slot++)
        if (sc->rxslot[slot].oth_flags & ENOTHER_FREE)
          break;
      if (slot == sc->en_nrx)
        return(ENOSPC);
      sc->rxvc2slot[vci] = slot;
      sc->rxslot[slot].rxhand = NULL;
      oldmode = sc->rxslot[slot].mode;
      newmode = (flags & ATM_PH_AAL5) ? MIDV_AAL5 : MIDV_NOAAL;
      sc->rxslot[slot].mode = MIDV_SETMODE(oldmode, newmode);
      sc->rxslot[slot].atm_vci = vci;
      sc->rxslot[slot].atm_flags = flags;
      sc->rxslot[slot].oth_flags = 0;
      sc->rxslot[slot].rxhand = pi->rxhand;
      if (sc->rxslot[slot].indma.ifq_head || sc->rxslot[slot].q.ifq_head)
        panic("en_rxctl: left over mbufs on enable");
      sc->txspeed[vci] = 0;       /* full speed to start */
      sc->txvc2slot[vci] = 0;     /* init value */
      sc->txslot[0].nref++;       /* bump reference count */
      en_loadvc(sc, vci);         /* does debug printf for us */
      return(0);
    }
  
    /*
     * turn off VCI
     */
  
    if (sc->rxvc2slot[vci] == RX_NONE)
      return(EINVAL);
    slot = sc->rxvc2slot[vci];
    if ((sc->rxslot[slot].oth_flags & (ENOTHER_FREE|ENOTHER_DRAIN)) != 0)
      return(EINVAL);
    s = splnet();         /* block out enintr() */
    oldmode = EN_READ(sc, MID_VC(vci));
    newmode = MIDV_SETMODE(oldmode, MIDV_TRASH) & ~MIDV_INSERVICE;
    EN_WRITE(sc, MID_VC(vci), (newmode | (oldmode & MIDV_INSERVICE)));
                  /* halt in tracks, be careful to preserve inserivce bit */
    DELAY(27);
    sc->rxslot[slot].rxhand = NULL;
    sc->rxslot[slot].mode = newmode;
  
    sc->txslot[sc->txvc2slot[vci]].nref--;
    sc->txspeed[vci] = 0;
    sc->txvc2slot[vci] = 0;
  
    /* if stuff is still going on we are going to have to drain it out */
    if (sc->rxslot[slot].indma.ifq_head ||
                  sc->rxslot[slot].q.ifq_head ||
                  (sc->rxslot[slot].oth_flags & ENOTHER_SWSL) != 0) {
      sc->rxslot[slot].oth_flags |= ENOTHER_DRAIN;
    } else {
      sc->rxslot[slot].oth_flags = ENOTHER_FREE;
      sc->rxslot[slot].atm_vci = RX_NONE;
      sc->rxvc2slot[vci] = RX_NONE;
    }
    splx(s);              /* enable enintr() */
  #ifdef EN_DEBUG
    printf("%s: rx%d: VCI %d is now %s\n", sc->sc_dev.dv_xname, slot, vci,
          (sc->rxslot[slot].oth_flags & ENOTHER_DRAIN) ? "draining" : "free");
  #endif
    return(0);
  }
  
  /***********************************************************************/
  
  /*
   * en_reset: reset the board, throw away work in progress.
   * must en_init to recover.
   */
  
  void en_reset(sc)
  
  struct en_softc *sc;
  
  {
    struct mbuf *m;
    int lcv, slot;
  
  #ifdef EN_DEBUG
    printf("%s: reset\n", sc->sc_dev.dv_xname);
  #endif
  
    if (sc->en_busreset)
      sc->en_busreset(sc);
    EN_WRITE(sc, MID_RESID, 0x0); /* reset hardware */
  
    /*
     * recv: dump any mbufs we are DMA'ing into, if DRAINing, then a reset
     * will free us!
     */
  
    for (lcv = 0 ; lcv < MID_N_VC ; lcv++) {
      if (sc->rxvc2slot[lcv] == RX_NONE)
        continue;
      slot = sc->rxvc2slot[lcv];
      while (1) {
        IF_DEQUEUE(&sc->rxslot[slot].indma, m);
        if (m == NULL)
          break;          /* >>> exit 'while(1)' here <<< */
        m_freem(m);
      }
      while (1) {
        IF_DEQUEUE(&sc->rxslot[slot].q, m);
        if (m == NULL)
          break;          /* >>> exit 'while(1)' here <<< */
        m_freem(m);
      }
      sc->rxslot[slot].oth_flags &= ~ENOTHER_SWSL;
      if (sc->rxslot[slot].oth_flags & ENOTHER_DRAIN) {
        sc->rxslot[slot].oth_flags = ENOTHER_FREE;
        sc->rxvc2slot[lcv] = RX_NONE;
  #ifdef EN_DEBUG
    printf("%s: rx%d: VCI %d is now free\n", sc->sc_dev.dv_xname, slot, lcv);
  #endif
      }
    }
  
    /*
     * xmit: dump everything
     */
  
    for (lcv = 0 ; lcv < EN_NTX ; lcv++) {
      while (1) {
        IF_DEQUEUE(&sc->txslot[lcv].indma, m);
        if (m == NULL)
          break;          /* >>> exit 'while(1)' here <<< */
        m_freem(m);
      }
      while (1) {
        IF_DEQUEUE(&sc->txslot[lcv].q, m);
        if (m == NULL)
          break;          /* >>> exit 'while(1)' here <<< */
        m_freem(m);
      }
      sc->txslot[lcv].mbsize = 0;
    }
  
    return;
  }
  
  
  /*
   * en_init: init board and sync the card with the data in the softc.
   */
  
  STATIC void en_init(sc)
  
  struct en_softc *sc;
  
  {
    int vc, slot;
    u_int32_t loc;
  #ifdef ATM_PVCEXT
      struct pvcsif *pvcsif;
  #endif
  
    if ((sc->enif.if_flags & IFF_UP) == 0) {
  #ifdef ATM_PVCEXT
      LIST_FOREACH(pvcsif, &sc->sif_list, sif_links) {
        if (pvcsif->sif_if.if_flags & IFF_UP) {
          /*
           * down the device only when there is no active pvc subinterface.
           * if there is, we have to go through the init sequence to reflect
           * the software states to the device.
           */
          goto up;
        }
      }
  #endif
  #ifdef EN_DEBUG
      printf("%s: going down\n", sc->sc_dev.dv_xname);
  #endif
      en_reset(sc);                       /* to be safe */
      sc->enif.if_flags &= ~IFF_RUNNING;  /* disable */
      return;
    }
  
  #ifdef ATM_PVCEXT
   up:
  #endif
  #ifdef EN_DEBUG
    printf("%s: going up\n", sc->sc_dev.dv_xname);
  #endif
    sc->enif.if_flags |= IFF_RUNNING;     /* enable */
  #ifdef ATM_PVCEXT
    LIST_FOREACH(pvcsif, &sc->sif_list, sif_links) {
      pvcsif->sif_if.if_flags |= IFF_RUNNING;
    }
  #endif
  
    if (sc->en_busreset)
      sc->en_busreset(sc);
    EN_WRITE(sc, MID_RESID, 0x0);         /* reset */
  
    /*
     * init obmem data structures: vc tab, DMA q's, slist.
     *
     * note that we set drq_free/dtq_free to one less than the total number
     * of DTQ/DRQs present.   we do this because the card uses the condition
     * (drq_chip == drq_us) to mean "list is empty"... but if you allow the
     * circular list to be completely full then (drq_chip == drq_us) [i.e.
     * the drq_us pointer will wrap all the way around].   by restricting
     * the number of active requests to (N - 1) we prevent the list from
     * becoming completely full.    note that the card will sometimes give
     * us an interrupt for a DTQ/DRQ we have already processes... this helps
     * keep that interrupt from messing us up.
     */
  
    for (vc = 0 ; vc < MID_N_VC ; vc++)
      en_loadvc(sc, vc);
  
    memset(&sc->drq, 0, sizeof(sc->drq));
    sc->drq_free = MID_DRQ_N - 1;         /* N - 1 */
    sc->drq_chip = MID_DRQ_REG2A(EN_READ(sc, MID_DMA_RDRX));
    EN_WRITE(sc, MID_DMA_WRRX, MID_DRQ_A2REG(sc->drq_chip));
                                                  /* ensure zero queue */
    sc->drq_us = sc->drq_chip;
  
    memset(&sc->dtq, 0, sizeof(sc->dtq));
    sc->dtq_free = MID_DTQ_N - 1;         /* N - 1 */
    sc->dtq_chip = MID_DTQ_REG2A(EN_READ(sc, MID_DMA_RDTX));
    EN_WRITE(sc, MID_DMA_WRTX, MID_DRQ_A2REG(sc->dtq_chip));
                                                  /* ensure zero queue */
    sc->dtq_us = sc->dtq_chip;
  
    sc->hwslistp = MID_SL_REG2A(EN_READ(sc, MID_SERV_WRITE));
    sc->swsl_size = sc->swsl_head = sc->swsl_tail = 0;
  
  #ifdef EN_DEBUG
    printf("%s: drq free/chip: %d/0x%x, dtq free/chip: %d/0x%x, hwslist: 0x%x\n",
      sc->sc_dev.dv_xname, sc->drq_free, sc->drq_chip,
      sc->dtq_free, sc->dtq_chip, sc->hwslistp);
  #endif
  
    for (slot = 0 ; slot < EN_NTX ; slot++) {
      sc->txslot[slot].bfree = EN_TXSZ * 1024;
      EN_WRITE(sc, MIDX_READPTR(slot), 0);
      EN_WRITE(sc, MIDX_DESCSTART(slot), 0);
      loc = sc->txslot[slot].cur = sc->txslot[slot].start;
      loc = loc - MID_RAMOFF;
      loc = (loc & ~((EN_TXSZ*1024) - 1)) >> 2; /* mask, cvt to words */
      loc = loc >> MIDV_LOCTOPSHFT;       /* top 11 bits */
      EN_WRITE(sc, MIDX_PLACE(slot), MIDX_MKPLACE(en_k2sz(EN_TXSZ), loc));
  #ifdef EN_DEBUG
      printf("%s: tx%d: place 0x%x\n", sc->sc_dev.dv_xname,  slot,
          EN_READ(sc, MIDX_PLACE(slot)));
  #endif
    }
  
    /*
     * enable!
     */
  
    EN_WRITE(sc, MID_INTENA, MID_INT_TX|MID_INT_DMA_OVR|MID_INT_IDENT|
          MID_INT_LERR|MID_INT_DMA_ERR|MID_INT_DMA_RX|MID_INT_DMA_TX|
          MID_INT_SERVICE| /* >>> MID_INT_SUNI| XXXCDC<<< */ MID_INT_STATS);
    EN_WRITE(sc, MID_MAST_CSR, MID_SETIPL(sc->ipl)|MID_MCSR_ENDMA|
          MID_MCSR_ENTX|MID_MCSR_ENRX);
  
  }
  
  
  /*
   * en_loadvc: load a vc tab entry from a slot
   */
  
  STATIC void en_loadvc(sc, vc)
  
  struct en_softc *sc;
  int vc;
  
  {
    int slot;
    u_int32_t reg = EN_READ(sc, MID_VC(vc));
  
    reg = MIDV_SETMODE(reg, MIDV_TRASH);
    EN_WRITE(sc, MID_VC(vc), reg);
    DELAY(27);
  
    if ((slot = sc->rxvc2slot[vc]) == RX_NONE)
      return;
  
    /* no need to set CRC */
    EN_WRITE(sc, MID_DST_RP(vc), 0);      /* read pointer = 0, desc. start = 0 */
    EN_WRITE(sc, MID_WP_ST_CNT(vc), 0);   /* write pointer = 0 */
    EN_WRITE(sc, MID_VC(vc), sc->rxslot[slot].mode);  /* set mode, size, loc */
    sc->rxslot[slot].cur = sc->rxslot[slot].start;
  
  #ifdef EN_DEBUG
      printf("%s: rx%d: assigned to VCI %d\n", sc->sc_dev.dv_xname, slot, vc);
  #endif
  }
  
  
  /*
   * en_start: start transmitting the next packet that needs to go out
   * if there is one.    note that atm_output() has already splnet()'d us.
   */
  
  STATIC void en_start(ifp)
  
  struct ifnet *ifp;
  
  {
  #ifdef MISSING_IF_SOFTC
      struct en_softc *sc = (struct en_softc *) en_cd.cd_devs[ifp->if_unit];
  #else
      struct en_softc *sc = (struct en_softc *) ifp->if_softc;
  #endif
      struct mbuf *m, *lastm, *prev;
      struct atm_pseudohdr *ap, *new_ap;
      int txchan, mlen, got, need, toadd, cellcnt, first;
      u_int32_t atm_vpi, atm_vci, atm_flags, *dat, aal;
      u_int8_t *cp;
  
      if ((ifp->if_flags & IFF_RUNNING) == 0)
          return;
  
      /*
       * remove everything from interface queue since we handle all queueing
       * locally ...
       */
  
      while (1) {
  
        IFQ_DEQUEUE(&ifp->if_snd, m);
        if (m == NULL)
          return;         /* EMPTY: >>> exit here <<< */
  
        /*
         * calculate size of packet (in bytes)
         * also, if we are not doing transmit DMA we eliminate all stupid
         * (non-word) alignments here using en_mfix().   calls to en_mfix()
         * seem to be due to tcp retransmits for the most part.
         *
         * after this loop mlen total length of mbuf chain (including atm_ph),
         * and lastm is a pointer to the last mbuf on the chain.
         */
  
        lastm = m;
        mlen = 0;
        prev = NULL;
        while (1) {
          /* no DMA? */
          if ((!sc->is_adaptec && EN_ENIDMAFIX) || EN_NOTXDMA || !en_dma) {
            if ( (mtod(lastm, unsigned long) % sizeof(u_int32_t)) != 0 ||
              ((lastm->m_len % sizeof(u_int32_t)) != 0 && lastm->m_next)) {
              first = (lastm == m);
              if (en_mfix(sc, &lastm, prev) == 0) {       /* failed? */
                m_freem(m);
                m = NULL;
                break;
              }
              if (first)
                m = lastm;                /* update */
            }
            prev = lastm;
          }
          mlen += lastm->m_len;
          if (lastm->m_next == NULL)
            break;
          lastm = lastm->m_next;
        }
  
        if (m == NULL)            /* happens only if mfix fails */
          continue;
  
        ap = mtod(m, struct atm_pseudohdr *);
  
        atm_vpi = ATM_PH_VPI(ap);
        atm_vci = ATM_PH_VCI(ap);
        atm_flags = ATM_PH_FLAGS(ap) & ~(EN_OBHDR|EN_OBTRL);
        aal = ((atm_flags & ATM_PH_AAL5) != 0)
                          ? MID_TBD_AAL5 : MID_TBD_NOAAL5;
  
        /*
         * check that vpi/vci is one we can use
         */
  
        if (atm_vpi || atm_vci > MID_N_VC) {
          printf("%s: output vpi=%d, vci=%d out of card range, dropping...\n",
                  sc->sc_dev.dv_xname, atm_vpi, atm_vci);
          m_freem(m);
          continue;
        }
  
        /*
         * computing how much padding we need on the end of the mbuf, then
         * see if we can put the TBD at the front of the mbuf where the
         * link header goes (well behaved protocols will reserve room for us).
         * last, check if room for PDU tail.
         *
         * got = number of bytes of data we have
         * cellcnt = number of cells in this mbuf
         * need = number of bytes of data + padding we need (excludes TBD)
         * toadd = number of bytes of data we need to add to end of mbuf,
         *        [including AAL5 PDU, if AAL5]
         */
  
        got = mlen - sizeof(struct atm_pseudohdr);
        toadd = (aal == MID_TBD_AAL5) ? MID_PDU_SIZE : 0; /* PDU */
        cellcnt = (got + toadd + (MID_ATMDATASZ - 1)) / MID_ATMDATASZ;
        need = cellcnt * MID_ATMDATASZ;
        toadd = need - got;               /* recompute, including zero padding */
  
  #ifdef EN_DEBUG
        printf("%s: txvci%d: mlen=%d, got=%d, need=%d, toadd=%d, cell#=%d\n",
          sc->sc_dev.dv_xname, atm_vci, mlen, got, need, toadd, cellcnt);
        printf("     leading_space=%d, trailing_space=%d\n",
          M_LEADINGSPACE(m), M_TRAILINGSPACE(lastm));
  #endif
  
  #ifdef EN_MBUF_OPT
  
        /*
         * note: external storage (M_EXT) can be shared between mbufs
         * to avoid copying (see m_copym()).    this means that the same
         * data buffer could be shared by several mbufs, and thus it isn't
         * a good idea to try and write TBDs or PDUs to M_EXT data areas.
         */
  
        if (M_LEADINGSPACE(m) >= MID_TBD_SIZE && (m->m_flags & M_EXT) == 0) {
          m->m_data -= MID_TBD_SIZE;
          m->m_len += MID_TBD_SIZE;
          mlen += MID_TBD_SIZE;
          new_ap = mtod(m, struct atm_pseudohdr *);
          *new_ap = *ap;                  /* move it back */
          ap = new_ap;
          dat = ((u_int32_t *) ap) + 1;
          /* make sure the TBD is in proper byte order */
          *dat++ = htonl(MID_TBD_MK1(aal, sc->txspeed[atm_vci], cellcnt));
          *dat = htonl(MID_TBD_MK2(atm_vci, 0, 0));
          atm_flags |= EN_OBHDR;
        }
  
        if (toadd && (lastm->m_flags & M_EXT) == 0 &&
                                          M_TRAILINGSPACE(lastm) >= toadd) {
          cp = mtod(lastm, u_int8_t *) + lastm->m_len;
          lastm->m_len += toadd;
          mlen += toadd;
          if (aal == MID_TBD_AAL5) {
            memset(cp, 0, toadd - MID_PDU_SIZE);
            dat = (u_int32_t *)(cp + toadd - MID_PDU_SIZE);
            /* make sure the PDU is in proper byte order */
            *dat = htonl(MID_PDU_MK1(0, 0, got));
          } else {
            memset(cp, 0, toadd);
          }
          atm_flags |= EN_OBTRL;
        }
        ATM_PH_FLAGS(ap) = atm_flags;     /* update EN_OBHDR/EN_OBTRL bits */
  #endif  /* EN_MBUF_OPT */
  
        /*
         * get assigned channel (will be zero unless txspeed[atm_vci] is set)
         */
  
        txchan = sc->txvc2slot[atm_vci];
  
        if (sc->txslot[txchan].mbsize > EN_TXHIWAT) {
          EN_COUNT(sc->txmbovr);
          m_freem(m);
  #ifdef EN_DEBUG
          printf("%s: tx%d: buffer space shortage\n", sc->sc_dev.dv_xname,
                  txchan);
  #endif
          continue;
        }
  
        sc->txslot[txchan].mbsize += mlen;
  
  #ifdef EN_DEBUG
        printf("%s: tx%d: VPI=%d, VCI=%d, FLAGS=0x%x, speed=0x%x\n",
          sc->sc_dev.dv_xname, txchan, atm_vpi, atm_vci, atm_flags,
          sc->txspeed[atm_vci]);
        printf("     adjusted mlen=%d, mbsize=%d\n", mlen,
                  sc->txslot[txchan].mbsize);
  #endif
  
        IF_ENQUEUE(&sc->txslot[txchan].q, m);
        en_txdma(sc, txchan);
  
    }
    /*NOTREACHED*/
  }
  
  
  /*
   * en_mfix: fix a stupid mbuf
   */
  
  #ifndef __FreeBSD__
  
  STATIC int en_mfix(sc, mm, prev)
  
  struct en_softc *sc;
  struct mbuf **mm, *prev;
  
  {
    struct mbuf *m, *new;
    u_char *d, *cp;
    int off;
    struct mbuf *nxt;
  
    m = *mm;
  
    EN_COUNT(sc->mfix);                   /* count # of calls */
  #ifdef EN_DEBUG
    printf("%s: mfix mbuf m_data=%p, m_len=%d\n", sc->sc_dev.dv_xname,
          m->m_data, m->m_len);
  #endif
  
    d = mtod(m, u_char *);
    off = ((unsigned long) d) % sizeof(u_int32_t);
  
    if (off) {
      if ((m->m_flags & M_EXT) == 0) {
        memmove(d - off, d, m->m_len);   /* ALIGN! (with costly data copy...) */
        d -= off;
        m->m_data = (caddr_t)d;
      } else {
        /* can't write to an M_EXT mbuf since it may be shared */
        MGET(new, M_DONTWAIT, MT_DATA);
        if (!new) {
          EN_COUNT(sc->mfixfail);
          return(0);
        }
        MCLGET(new, M_DONTWAIT);
        if ((new->m_flags & M_EXT) == 0) {
          m_free(new);
          EN_COUNT(sc->mfixfail);
          return(0);
        }
        memcpy(new->m_data, d, m->m_len); /* ALIGN! (with costly data copy...) */
        new->m_len = m->m_len;
        new->m_next = m->m_next;
        if (prev)
          prev->m_next = new;
        m_free(m);
        *mm = m = new;    /* note: 'd' now invalid */
      }
    }
  
    off = m->m_len % sizeof(u_int32_t);
    if (off == 0)
      return(1);
  
    d = mtod(m, u_char *) + m->m_len;
    off = sizeof(u_int32_t) - off;
  
    nxt = m->m_next;
    while (off--) {
      for ( ; nxt != NULL && nxt->m_len == 0 ; nxt = nxt->m_next)
        /*null*/;
      if (nxt == NULL) {          /* out of data, zero fill */
        *d++ = 0;
        continue;                 /* next "off" */
      }
      cp = mtod(nxt, u_char *);
      *d++ = *cp++;
      m->m_len++;
      nxt->m_len--;
      nxt->m_data = (caddr_t)cp;
    }
    return(1);
  }
  
  #else /* __FreeBSD__ */
  
  STATIC int en_makeexclusive(struct en_softc *, struct mbuf **, struct mbuf *);
  
  STATIC int en_makeexclusive(sc, mm, prev)
      struct en_softc *sc;
      struct mbuf **mm, *prev;
  {
      struct mbuf *m, *new;
  
      m = *mm;
  
      if (m->m_flags & M_EXT) {
          if (m->m_ext.ext_free) {
              /* external buffer isn't an ordinary mbuf cluster! */
              printf("%s: mfix: special buffer! can't make a copy!\n",
                     sc->sc_dev.dv_xname);
              return (0);
          }
  
          if (mclrefcnt[mtocl(m->m_ext.ext_buf)] > 1) {
              /* make a real copy of the M_EXT mbuf since it is shared */
              MGET(new, M_DONTWAIT, MT_DATA);
              if (!new) {
                  EN_COUNT(sc->mfixfail);
                  return(0);
              }
              if (m->m_flags & M_PKTHDR)
                  M_COPY_PKTHDR(new, m);
              MCLGET(new, M_DONTWAIT);
              if ((new->m_flags & M_EXT) == 0) {
                  m_free(new);
                  EN_COUNT(sc->mfixfail);
                  return(0);
              }
              memcpy(new->m_data, m->m_data, m->m_len);
              new->m_len = m->m_len;
              new->m_next = m->m_next;
              if (prev)
                  prev->m_next = new;
              m_free(m);
              *mm = new;
          }
          else {
              /* the buffer is not shared, align the data offset using
                 this buffer. */
              u_char *d = mtod(m, u_char *);
              int off = ((u_long)d) % sizeof(u_int32_t);
  
              if (off > 0) {
                  memmove(d - off, d, m->m_len);
                  m->m_data = (caddr_t)d - off;
              }
          }
      }
      return (1);
  }
  
  STATIC int en_mfix(sc, mm, prev)
  
  struct en_softc *sc;
  struct mbuf **mm, *prev;
  
  {
    struct mbuf *m;
    u_char *d, *cp;
    int off;
    struct mbuf *nxt;
  
    m = *mm;
  
    EN_COUNT(sc->mfix);                   /* count # of calls */
  #ifdef EN_DEBUG
    printf("%s: mfix mbuf m_data=0x%x, m_len=%d\n", sc->sc_dev.dv_xname,
          m->m_data, m->m_len);
  #endif
  
    d = mtod(m, u_char *);
    off = ((unsigned long) d) % sizeof(u_int32_t);
  
    if (off) {
      if ((m->m_flags & M_EXT) == 0) {
        memmove(d - off, d, m->m_len);   /* ALIGN! (with costly data copy...) */
        d -= off;
        m->m_data = (caddr_t)d;
      } else {
        /* can't write to an M_EXT mbuf since it may be shared */
        if (en_makeexclusive(sc, &m, prev) == 0)
            return (0);
        *mm = m;  /* note: 'd' now invalid */
      }
    }
  
    off = m->m_len % sizeof(u_int32_t);
    if (off == 0)
      return(1);
  
    if (m->m_flags & M_EXT) {
        /* can't write to an M_EXT mbuf since it may be shared */
        if (en_makeexclusive(sc, &m, prev) == 0)
            return (0);
        *mm = m;  /* note: 'd' now invalid */
    }
  
    d = mtod(m, u_char *) + m->m_len;
    off = sizeof(u_int32_t) - off;
  
    nxt = m->m_next;
    while (off--) {
      if (nxt != NULL && nxt->m_len == 0) {
          /* remove an empty mbuf.  this avoids odd byte padding to an empty
             last mbuf.  */
          m->m_next = nxt = m_free(nxt);
      }
      if (nxt == NULL) {          /* out of data, zero fill */
        *d++ = 0;
        continue;                 /* next "off" */
      }
      cp = mtod(nxt, u_char *);
      *d++ = *cp++;
      m->m_len++;
      nxt->m_len--;
      nxt->m_data = (caddr_t)cp;
    }
    if (nxt != NULL && nxt->m_len == 0)
        m->m_next = m_free(nxt);
    return(1);
  }
  
  #endif /* __FreeBSD__ */
  
  /*
   * en_txdma: start transmit DMA, if possible
   */
  
  STATIC void en_txdma(sc, chan)
  
  struct en_softc *sc;
  int chan;
  
  {
    struct mbuf *tmp;
    struct atm_pseudohdr *ap;
    struct en_launch launch;
    int datalen = 0, dtqneed, len, ncells;
    u_int8_t *cp;
    struct ifnet *ifp;
  
  #ifdef EN_DEBUG
    printf("%s: tx%d: starting...\n", sc->sc_dev.dv_xname, chan);
  #endif
  
    /*
     * note: now that txlaunch handles non-word aligned/sized requests
     * the only time you can safely set launch.nodma is if you've en_mfix()'d
     * the mbuf chain.    this happens only if EN_NOTXDMA || !en_dma.
     */
  
    launch.nodma = (EN_NOTXDMA || !en_dma);
  
  again:
  
    /*
     * get an mbuf waiting for DMA
     */
  
    launch.t = sc->txslot[chan].q.ifq_head; /* peek at head of queue */
  
    if (launch.t == NULL) {
  #ifdef EN_DEBUG
      printf("%s: tx%d: ...done!\n", sc->sc_dev.dv_xname, chan);
  #endif
      return;     /* >>> exit here if no data waiting for DMA <<< */
    }
  
    /*
     * get flags, vci
     *
     * note: launch.need = # bytes we need to get on the card
     *       dtqneed = # of DTQs we need for this packet
     *       launch.mlen = # of bytes in in mbuf chain (<= launch.need)
     */
  
    ap = mtod(launch.t, struct atm_pseudohdr *);
    launch.atm_vci = ATM_PH_VCI(ap);
    launch.atm_flags = ATM_PH_FLAGS(ap);
    launch.aal = ((launch.atm_flags & ATM_PH_AAL5) != 0) ?
                  MID_TBD_AAL5 : MID_TBD_NOAAL5;
  
    /*
     * XXX: have to recompute the length again, even though we already did
     * it in en_start().   might as well compute dtqneed here as well, so
     * this isn't that bad.
     */
  
    if ((launch.atm_flags & EN_OBHDR) == 0) {
      dtqneed = 1;                /* header still needs to be added */
      launch.need = MID_TBD_SIZE; /* not included with mbuf */
    } else {
      dtqneed = 0;                /* header on-board, DMA with mbuf */
      launch.need = 0;
    }
  
    launch.mlen = 0;
    for (tmp = launch.t ; tmp != NULL ; tmp = tmp->m_next) {
      len = tmp->m_len;
      launch.mlen += len;
      cp = mtod(tmp, u_int8_t *);
      if (tmp == launch.t) {
        len -= sizeof(struct atm_pseudohdr); /* don't count this! */
        cp += sizeof(struct atm_pseudohdr);
      }
      launch.need += len;
      if (len == 0)
        continue;                 /* atm_pseudohdr alone in first mbuf */
  
      dtqneed += en_dqneed(sc, (caddr_t) cp, len, 1);
    }
  
    if ((launch.need % sizeof(u_int32_t)) != 0)
      dtqneed++;                  /* need DTQ to FLUSH internal buffer */
  
    if ((launch.atm_flags & EN_OBTRL) == 0) {
      if (launch.aal == MID_TBD_AAL5) {
        datalen = launch.need - MID_TBD_SIZE;
        launch.need += MID_PDU_SIZE;              /* AAL5: need PDU tail */
      }
      dtqneed++;                  /* need to work on the end a bit */
    }
  
    /*
     * finish calculation of launch.need (need to figure out how much padding
     * we will need).   launch.need includes MID_TBD_SIZE, but we need to
     * remove that to so we can round off properly.     we have to add
     * MID_TBD_SIZE back in after calculating ncells.
     */
  
    launch.need = roundup(launch.need - MID_TBD_SIZE, MID_ATMDATASZ);
    ncells = launch.need / MID_ATMDATASZ;
    launch.need += MID_TBD_SIZE;
  
    if (launch.need > EN_TXSZ * 1024) {
      printf("%s: tx%d: packet larger than xmit buffer (%d > %d)\n",
        sc->sc_dev.dv_xname, chan, launch.need, EN_TXSZ * 1024);
      goto dequeue_drop;
    }
  
    /*
     * note: note that we cannot totally fill the circular buffer (i.e.
     * we can't use up all of the remaining sc->txslot[chan].bfree free
     * bytes) because that would cause the circular buffer read pointer
     * to become equal to the write pointer, thus signaling 'empty buffer'
     * to the hardware and stopping the transmitter.
     */
    if (launch.need >= sc->txslot[chan].bfree) {
      EN_COUNT(sc->txoutspace);
  #ifdef EN_DEBUG
      printf("%s: tx%d: out of transmit space\n", sc->sc_dev.dv_xname, chan);
  #endif
      return;             /* >>> exit here if out of obmem buffer space <<< */
    }
  
    /*
     * ensure we have enough dtqs to go, if not, wait for more.
     */
  
    if (launch.nodma) {
      dtqneed = 1;
    }
    if (dtqneed > sc->dtq_free) {
      sc->need_dtqs = 1;
      EN_COUNT(sc->txdtqout);
  #ifdef EN_DEBUG
      printf("%s: tx%d: out of transmit DTQs\n", sc->sc_dev.dv_xname, chan);
  #endif
      return;             /* >>> exit here if out of dtqs <<< */
    }
  
    /*
     * it is a go, commit!  dequeue mbuf start working on the xfer.
     */
  
    IF_DEQUEUE(&sc->txslot[chan].q, tmp);
  #ifdef EN_DIAG
    if (launch.t != tmp)
      panic("en dequeue");
  #endif /* EN_DIAG */
  
    /*
     * launch!
     */
  
    EN_COUNT(sc->launch);
  #ifdef ATM_PVCEXT
    /* if there's a subinterface for this vci, override ifp. */
    ifp = en_vci2ifp(sc, launch.atm_vci);
  #else
    ifp = &sc->enif;
  #endif
    ifp->if_opackets++;
  
    if ((launch.atm_flags & EN_OBHDR) == 0) {
      EN_COUNT(sc->lheader);
      /* store tbd1/tbd2 in host byte order */
      launch.tbd1 = MID_TBD_MK1(launch.aal, sc->txspeed[launch.atm_vci], ncells);
      launch.tbd2 = MID_TBD_MK2(launch.atm_vci, 0, 0);
    }
    if ((launch.atm_flags & EN_OBTRL) == 0 && launch.aal == MID_TBD_AAL5) {
      EN_COUNT(sc->ltail);
      launch.pdu1 = MID_PDU_MK1(0, 0, datalen);  /* host byte order */
    }
  
    en_txlaunch(sc, chan, &launch);
  
  #if NBPFILTER > 0
    if (ifp->if_bpf) {
        /*
         * adjust the top of the mbuf to skip the pseudo atm header
         * (and TBD, if present) before passing the packet to bpf,
         * restore it afterwards.
         */
        int size = sizeof(struct atm_pseudohdr);
        if (launch.atm_flags & EN_OBHDR)
            size += MID_TBD_SIZE;
  
        launch.t->m_data += size;
        launch.t->m_len -= size;
  
        BPF_MTAP(ifp, launch.t);
  
        launch.t->m_data -= size;
        launch.t->m_len += size;
    }
  #endif /* NBPFILTER > 0 */
    /*
     * do some housekeeping and get the next packet
     */
  
    sc->txslot[chan].bfree -= launch.need;
    IF_ENQUEUE(&sc->txslot[chan].indma, launch.t);
    goto again;
  
    /*
     * END of txdma loop!
     */
  
    /*
     * error handles
     */
  
  dequeue_drop:
    IF_DEQUEUE(&sc->txslot[chan].q, tmp);
    if (launch.t != tmp)
      panic("en dequeue drop");
    m_freem(launch.t);
    sc->txslot[chan].mbsize -= launch.mlen;
    goto again;
  }
  
  
  /*
   * en_txlaunch: launch an mbuf into the DMA pool!
   */
  
  STATIC void en_txlaunch(sc, chan, l)
  
  struct en_softc *sc;
  int chan;
  struct en_launch *l;
  
  {
    struct mbuf *tmp;
    u_int32_t cur = sc->txslot[chan].cur,
              start = sc->txslot[chan].start,
              stop = sc->txslot[chan].stop,
              dma, *data, *datastop, count, bcode;
    int pad, addtail, need, len, needalign, cnt, end, mx;
  
  
   /*
    * vars:
    *   need = # bytes card still needs (decr. to zero)
    *   len = # of bytes left in current mbuf
    *   cur = our current pointer
    *   dma = last place we programmed into the DMA
    *   data = pointer into data area of mbuf that needs to go next
    *   cnt = # of bytes to transfer in this DTQ
    *   bcode/count = DMA burst code, and chip's version of cnt
    *
    *   a single buffer can require up to 5 DTQs depending on its size
    *   and alignment requirements.   the 5 possible requests are:
    *   [1] 1, 2, or 3 byte DMA to align src data pointer to word boundary
    *   [2] alburst DMA to align src data pointer to bestburstlen
    *   [3] 1 or more bestburstlen DMAs
    *   [4] clean up burst (to last word boundary)
    *   [5] 1, 2, or 3 byte final clean up DMA
    */
  
   need = l->need;
   dma = cur;
   addtail = (l->atm_flags & EN_OBTRL) == 0;      /* add a tail? */
  
  #ifdef EN_DIAG
    if ((need - MID_TBD_SIZE) % MID_ATMDATASZ)
      printf("%s: tx%d: bogus transmit needs (%d)\n", sc->sc_dev.dv_xname, chan,
                  need);
  #endif
  #ifdef EN_DEBUG
    printf("%s: tx%d: launch mbuf %p!   cur=0x%x[%d], need=%d, addtail=%d\n",
          sc->sc_dev.dv_xname, chan, l->t, cur, (cur-start)/4, need, addtail);
    count = EN_READ(sc, MIDX_PLACE(chan));
    printf("     HW: base_address=0x%x, size=%d, read=%d, descstart=%d\n",
          MIDX_BASE(count), MIDX_SZ(count), EN_READ(sc, MIDX_READPTR(chan)),
          EN_READ(sc, MIDX_DESCSTART(chan)));
  #endif
  
   /*
    * do we need to insert the TBD by hand?
    * note that tbd1/tbd2/pdu1 are in host byte order.
    */
  
    if ((l->atm_flags & EN_OBHDR) == 0) {
  #ifdef EN_DEBUG
      printf("%s: tx%d: insert header 0x%x 0x%x\n", sc->sc_dev.dv_xname,
          chan, l->tbd1, l->tbd2);
  #endif
      EN_WRITE(sc, cur, l->tbd1);
      EN_WRAPADD(start, stop, cur, 4);
      EN_WRITE(sc, cur, l->tbd2);
      EN_WRAPADD(start, stop, cur, 4);
      need -= 8;
    }
  
    /*
     * now do the mbufs...
     */
  
    for (tmp = l->t ; tmp != NULL ; tmp = tmp->m_next) {
  
      /* get pointer to data and length */
      data = mtod(tmp, u_int32_t *);
      len = tmp->m_len;
      if (tmp == l->t) {
        data += sizeof(struct atm_pseudohdr)/sizeof(u_int32_t);
        len -= sizeof(struct atm_pseudohdr);
      }
  
      /* now, determine if we should copy it */
      if (l->nodma || (len < EN_MINDMA &&
         (len % 4) == 0 && ((unsigned long) data % 4) == 0 && (cur % 4) == 0)) {
  
        /*
         * roundup len: the only time this will change the value of len
         * is when l->nodma is true, tmp is the last mbuf, and there is
         * a non-word number of bytes to transmit.   in this case it is
         * safe to round up because we've en_mfix'd the mbuf (so the first
         * byte is word aligned there must be enough free bytes at the end
         * to round off to the next word boundary)...
         */
        len = roundup(len, sizeof(u_int32_t));
        datastop = data + (len / sizeof(u_int32_t));
        /* copy loop: preserve byte order!!!  use WRITEDAT */
        while (data != datastop) {
          EN_WRITEDAT(sc, cur, *data);
          data++;
          EN_WRAPADD(start, stop, cur, 4);
        }
        need -= len;
  #ifdef EN_DEBUG
        printf("%s: tx%d: copied %d bytes (%d left, cur now 0x%x)\n",
                  sc->sc_dev.dv_xname, chan, len, need, cur);
  #endif
        continue;         /* continue on to next mbuf */
      }
  
      /* going to do DMA, first make sure the dtq is in sync. */
      if (dma != cur) {
        EN_DTQADD(sc, WORD_IDX(start,cur), chan, MIDDMA_JK, 0, 0, 0);
  #ifdef EN_DEBUG
        printf("%s: tx%d: dtq_sync: advance pointer to %d\n",
                  sc->sc_dev.dv_xname, chan, cur);
  #endif
      }
  
      /*
       * if this is the last buffer, and it looks like we are going to need to
       * flush the internal buffer, can we extend the length of this mbuf to
       * avoid the FLUSH?
       */
  
      if (tmp->m_next == NULL) {
        cnt = (need - len) % sizeof(u_int32_t);
        if (cnt && M_TRAILINGSPACE(tmp) >= cnt)
          len += cnt;                     /* pad for FLUSH */
      }
  
  #if !defined(MIDWAY_ENIONLY)
  
      /*
       * the adaptec DMA engine is smart and handles everything for us.
       */
  
      if (sc->is_adaptec) {
        /* need to DMA "len" bytes out to card */
        need -= len;
        EN_WRAPADD(start, stop, cur, len);
  #ifdef EN_DEBUG
        printf("%s: tx%d: adp_dma %d bytes (%d left, cur now 0x%x)\n",
                sc->sc_dev.dv_xname, chan, len, need, cur);
  #endif
        end = (need == 0) ? MID_DMA_END : 0;
        EN_DTQADD(sc, len, chan, 0, vtophys((vaddr_t)data), l->mlen, end);
        if (end)
          goto done;
        dma = cur;        /* update DMA pointer */
        continue;
      }
  #endif /* !MIDWAY_ENIONLY */
  
  #if !defined(MIDWAY_ADPONLY)
  
      /*
       * the ENI DMA engine is not so smart and need more help from us
       */
  
      /* do we need to do a DMA op to align to word boundary? */
      needalign = (unsigned long) data % sizeof(u_int32_t);
      if (needalign) {
        EN_COUNT(sc->headbyte);
        cnt = sizeof(u_int32_t) - needalign;
        if (cnt == 2 && len >= cnt) {
          count = 1;
          bcode = MIDDMA_2BYTE;
        } else {
          cnt = min(cnt, len);            /* prevent overflow */
          count = cnt;
          bcode = MIDDMA_BYTE;
        }
        need -= cnt;
        EN_WRAPADD(start, stop, cur, cnt);
  #ifdef EN_DEBUG
        printf("%s: tx%d: small al_dma %d bytes (%d left, cur now 0x%x)\n",
                sc->sc_dev.dv_xname, chan, cnt, need, cur);
  #endif
        len -= cnt;
        end = (need == 0) ? MID_DMA_END : 0;
        EN_DTQADD(sc, count, chan, bcode, vtophys((vaddr_t)data), l->mlen, end);
        if (end)
          goto done;
        data = (u_int32_t *) ((u_char *)data + cnt);
      }
  
      /* do we need to do a DMA op to align? */
      if (sc->alburst &&
          (needalign = (((unsigned long) data) & sc->bestburstmask)) != 0
          && len >= sizeof(u_int32_t)) {
        cnt = sc->bestburstlen - needalign;
        mx = len & ~(sizeof(u_int32_t)-1);        /* don't go past end */
        if (cnt > mx) {
          cnt = mx;
          count = cnt / sizeof(u_int32_t);
          bcode = MIDDMA_WORD;
        } else {
          count = cnt / sizeof(u_int32_t);
          bcode = en_dmaplan[count].bcode;
          count = cnt >> en_dmaplan[count].divshift;
        }
        need -= cnt;
        EN_WRAPADD(start, stop, cur, cnt);
  #ifdef EN_DEBUG
        printf("%s: tx%d: al_dma %d bytes (%d left, cur now 0x%x)\n",
                  sc->sc_dev.dv_xname, chan, cnt, need, cur);
  #endif
        len -= cnt;
        end = (need == 0) ? MID_DMA_END : 0;
        EN_DTQADD(sc, count, chan, bcode, vtophys((vaddr_t)data), l->mlen, end);
        if (end)
          goto done;
        data = (u_int32_t *) ((u_char *)data + cnt);
      }
  
      /* do we need to do a max-sized burst? */
      if (len >= sc->bestburstlen) {
        count = len >> sc->bestburstshift;
        cnt = count << sc->bestburstshift;
        bcode = sc->bestburstcode;
        need -= cnt;
        EN_WRAPADD(start, stop, cur, cnt);
  #ifdef EN_DEBUG
        printf("%s: tx%d: best_dma %d bytes (%d left, cur now 0x%x)\n",
                  sc->sc_dev.dv_xname, chan, cnt, need, cur);
  #endif
        len -= cnt;
        end = (need == 0) ? MID_DMA_END : 0;
        EN_DTQADD(sc, count, chan, bcode, vtophys((vaddr_t)data), l->mlen, end);
        if (end)
          goto done;
        data = (u_int32_t *) ((u_char *)data + cnt);
      }
  
      /* do we need to do a cleanup burst? */
      cnt = len & ~(sizeof(u_int32_t)-1);
      if (cnt) {
        count = cnt / sizeof(u_int32_t);
        bcode = en_dmaplan[count].bcode;
        count = cnt >> en_dmaplan[count].divshift;
        need -= cnt;
        EN_WRAPADD(start, stop, cur, cnt);
  #ifdef EN_DEBUG
        printf("%s: tx%d: cleanup_dma %d bytes (%d left, cur now 0x%x)\n",
                  sc->sc_dev.dv_xname, chan, cnt, need, cur);
  #endif
        len -= cnt;
        end = (need == 0) ? MID_DMA_END : 0;
        EN_DTQADD(sc, count, chan, bcode, vtophys((vaddr_t)data), l->mlen, end);
        if (end)
          goto done;
        data = (u_int32_t *) ((u_char *)data + cnt);
      }
  
      /* any word fragments left? */
      if (len) {
        EN_COUNT(sc->tailbyte);
        if (len == 2) {
          count = 1;
          bcode = MIDDMA_2BYTE;                 /* use 2byte mode */
        } else {
          count = len;
          bcode = MIDDMA_BYTE;                  /* use 1 byte mode */
        }
        need -= len;
        EN_WRAPADD(start, stop, cur, len);
  #ifdef EN_DEBUG
        printf("%s: tx%d: byte cleanup_dma %d bytes (%d left, cur now 0x%x)\n",
                sc->sc_dev.dv_xname, chan, len, need, cur);
  #endif
        end = (need == 0) ? MID_DMA_END : 0;
        EN_DTQADD(sc, count, chan, bcode, vtophys((vaddr_t)data), l->mlen, end);
        if (end)
          goto done;
      }
  
      dma = cur;          /* update DMA pointer */
  #endif /* !MIDWAY_ADPONLY */
  
    } /* next mbuf, please */
  
    /*
     * all mbuf data has been copied out to the obmem (or set up to be DMAd).
     * if the trailer or padding needs to be put in, do it now.
     *
     * NOTE: experimental results reveal the following fact:
     *   if you DMA "X" bytes to the card, where X is not a multiple of 4,
     *   then the card will internally buffer the last (X % 4) bytes (in
     *   hopes of getting (4 - (X % 4)) more bytes to make a complete word).
     *   it is imporant to make sure we don't leave any important data in
     *   this internal buffer because it is discarded on the last (end) DTQ.
     *   one way to do this is to DMA in (4 - (X % 4)) more bytes to flush
     *   the darn thing out.
     */
  
    if (addtail) {
  
      pad = need % sizeof(u_int32_t);
      if (pad) {
        /*
         * FLUSH internal data buffer.  pad out with random data from the front
         * of the mbuf chain...
         */
        bcode = (sc->is_adaptec) ? 0 : MIDDMA_BYTE;
        EN_COUNT(sc->tailflush);
        EN_WRAPADD(start, stop, cur, pad);
        EN_DTQADD(sc, pad, chan, bcode, vtophys((vaddr_t)l->t->m_data), 0, 0);
        need -= pad;
  #ifdef EN_DEBUG
        printf("%s: tx%d: pad/FLUSH DMA %d bytes (%d left, cur now 0x%x)\n",
                  sc->sc_dev.dv_xname, chan, pad, need, cur);
  #endif
      }
  
      /* copy data */
      pad = need / sizeof(u_int32_t);     /* round *down* */
      if (l->aal == MID_TBD_AAL5)
        pad -= 2;
  #ifdef EN_DEBUG
        printf("%s: tx%d: padding %d bytes (cur now 0x%x)\n",
                  sc->sc_dev.dv_xname, chan, pad * sizeof(u_int32_t), cur);
  #endif
      while (pad--) {
        EN_WRITEDAT(sc, cur, 0);  /* no byte order issues with zero */
        EN_WRAPADD(start, stop, cur, 4);
      }
      if (l->aal == MID_TBD_AAL5) {
        EN_WRITE(sc, cur, l->pdu1); /* in host byte order */
        EN_WRAPADD(start, stop, cur, 8);
      }
    }
  
    if (addtail || dma != cur) {
     /* write final descriptor  */
      EN_DTQADD(sc, WORD_IDX(start,cur), chan, MIDDMA_JK, 0,
                                  l->mlen, MID_DMA_END);
      /* dma = cur; */    /* not necessary since we are done */
    }
  
  done:
    /* update current pointer */
    sc->txslot[chan].cur = cur;
  #ifdef EN_DEBUG
        printf("%s: tx%d: DONE!   cur now = 0x%x\n",
                  sc->sc_dev.dv_xname, chan, cur);
  #endif
  
    return;
  }
  
  
  /*
   * interrupt handler
   */
  
  EN_INTR_TYPE en_intr(arg)
  
  void *arg;
  
  {
    struct en_softc *sc = (struct en_softc *) arg;
    struct mbuf *m;
    struct atm_pseudohdr ah;
    struct ifnet *ifp;
    u_int32_t reg, kick, val, mask, chip, vci, slot, dtq, drq;
    int lcv, idx, need_softserv = 0;
  
    reg = EN_READ(sc, MID_INTACK);
  
    if ((reg & MID_INT_ANY) == 0)
      EN_INTR_RET(0); /* not us */
  
  #ifdef EN_DEBUG
    {
      char sbuf[256];
  
      bitmask_snprintf(reg, MID_INTBITS, sbuf, sizeof(sbuf));
      printf("%s: interrupt=0x%s\n", sc->sc_dev.dv_xname, sbuf);
    }
  #endif
  
    /*
     * unexpected errors that need a reset
     */
  
    if ((reg & (MID_INT_IDENT|MID_INT_LERR|MID_INT_DMA_ERR|MID_INT_SUNI)) != 0) {
      char sbuf[256];
  
      bitmask_snprintf(reg, MID_INTBITS, sbuf, sizeof(sbuf));
      printf("%s: unexpected interrupt=0x%s, resetting card\n",
             sc->sc_dev.dv_xname, sbuf);
  #ifdef EN_DEBUG
  #ifdef DDB
  #ifdef __FreeBSD__
      Debugger("en: unexpected error");
  #else
      Debugger();
  #endif
  #endif  /* DDB */
      sc->enif.if_flags &= ~IFF_RUNNING; /* FREEZE! */
  #else
      en_reset(sc);
      en_init(sc);
  #endif
      EN_INTR_RET(1); /* for us */
    }
  
    /*******************
     * xmit interrupts *
     ******************/
  
    kick = 0;                             /* bitmask of channels to kick */
    if (reg & MID_INT_TX) {               /* TX done! */
  
      /*
       * check for tx complete, if detected then this means that some space
       * has come free on the card.   we must account for it and arrange to
       * kick the channel to life (in case it is stalled waiting on the card).
       */
      for (mask = 1, lcv = 0 ; lcv < EN_NTX ; lcv++, mask = mask * 2) {
        if (reg & MID_TXCHAN(lcv)) {
          kick = kick | mask;     /* want to kick later */
          val = EN_READ(sc, MIDX_READPTR(lcv));   /* current read pointer */
          val = (val * sizeof(u_int32_t)) + sc->txslot[lcv].start;
                                                  /* convert to offset */
          if (val > sc->txslot[lcv].cur)
            sc->txslot[lcv].bfree = val - sc->txslot[lcv].cur;
          else
            sc->txslot[lcv].bfree = (val + (EN_TXSZ*1024)) - sc->txslot[lcv].cur;
  #ifdef EN_DEBUG
          printf("%s: tx%d: transmit done.   %d bytes now free in buffer\n",
                  sc->sc_dev.dv_xname, lcv, sc->txslot[lcv].bfree);
  #endif
        }
      }
    }
  
    if (reg & MID_INT_DMA_TX) {           /* TX DMA done! */
  
    /*
     * check for TX DMA complete, if detected then this means that some DTQs
     * are now free.   it also means some indma mbufs can be freed.
     * if we needed DTQs, kick all channels.
     */
      val = EN_READ(sc, MID_DMA_RDTX);    /* chip's current location */
      idx = MID_DTQ_A2REG(sc->dtq_chip);/* where we last saw chip */
      if (sc->need_dtqs) {
        kick = MID_NTX_CH - 1;            /* assume power of 2, kick all! */
        sc->need_dtqs = 0;                /* recalculated in "kick" loop below */
  #ifdef EN_DEBUG
        printf("%s: cleared need DTQ condition\n", sc->sc_dev.dv_xname);
  #endif
      }
      while (idx != val) {
        sc->dtq_free++;
        if ((dtq = sc->dtq[idx]) != 0) {
          sc->dtq[idx] = 0;       /* don't forget to zero it out when done */
          slot = EN_DQ_SLOT(dtq);
          IF_DEQUEUE(&sc->txslot[slot].indma, m);
          if (!m) panic("enintr: dtqsync");
          sc->txslot[slot].mbsize -= EN_DQ_LEN(dtq);
  #ifdef EN_DEBUG
          printf("%s: tx%d: free %d DMA bytes, mbsize now %d\n",
                  sc->sc_dev.dv_xname, slot, EN_DQ_LEN(dtq),
                  sc->txslot[slot].mbsize);
  #endif
          m_freem(m);
        }
        EN_WRAPADD(0, MID_DTQ_N, idx, 1);
      };
      sc->dtq_chip = MID_DTQ_REG2A(val);  /* sync softc */
    }
  
  
    /*
     * kick xmit channels as needed
     */
  
    if (kick) {
  #ifdef EN_DEBUG
    printf("%s: tx kick mask = 0x%x\n", sc->sc_dev.dv_xname, kick);
  #endif
      for (mask = 1, lcv = 0 ; lcv < EN_NTX ; lcv++, mask = mask * 2) {
        if ((kick & mask) && sc->txslot[lcv].q.ifq_head) {
          en_txdma(sc, lcv);              /* kick it! */
        }
      }           /* for each slot */
    }             /* if kick */
  
  
    /*******************
     * recv interrupts *
     ******************/
  
    /*
     * check for RX DMA complete, and pass the data "upstairs"
     */
  
    if (reg & MID_INT_DMA_RX) {
      val = EN_READ(sc, MID_DMA_RDRX); /* chip's current location */
      idx = MID_DRQ_A2REG(sc->drq_chip);/* where we last saw chip */
      while (idx != val) {
        sc->drq_free++;
        if ((drq = sc->drq[idx]) != 0) {
          sc->drq[idx] = 0;       /* don't forget to zero it out when done */
          slot = EN_DQ_SLOT(drq);
          if (EN_DQ_LEN(drq) == 0) {  /* "JK" trash DMA? */
            m = NULL;
          } else {
            IF_DEQUEUE(&sc->rxslot[slot].indma, m);
            if (!m)
              panic("enintr: drqsync: %s: lost mbuf in slot %d!",
                    sc->sc_dev.dv_xname, slot);
          }
          /* do something with this mbuf */
          if (sc->rxslot[slot].oth_flags & ENOTHER_DRAIN) {  /* drain? */
            if (m)
              m_freem(m);
            vci = sc->rxslot[slot].atm_vci;
            if (sc->rxslot[slot].indma.ifq_head == NULL &&
                  sc->rxslot[slot].q.ifq_head == NULL &&
                  (EN_READ(sc, MID_VC(vci)) & MIDV_INSERVICE) == 0 &&
                  (sc->rxslot[slot].oth_flags & ENOTHER_SWSL) == 0) {
              sc->rxslot[slot].oth_flags = ENOTHER_FREE; /* done drain */
              sc->rxslot[slot].atm_vci = RX_NONE;
              sc->rxvc2slot[vci] = RX_NONE;
  #ifdef EN_DEBUG
              printf("%s: rx%d: VCI %d now free\n", sc->sc_dev.dv_xname,
                          slot, vci);
  #endif
            }
          } else if (m != NULL) {
            ATM_PH_FLAGS(&ah) = sc->rxslot[slot].atm_flags;
            ATM_PH_VPI(&ah) = 0;
            ATM_PH_SETVCI(&ah, sc->rxslot[slot].atm_vci);
  #ifdef EN_DEBUG
            printf("%s: rx%d: rxvci%d: atm_input, mbuf %p, len %d, hand %p\n",
                  sc->sc_dev.dv_xname, slot, sc->rxslot[slot].atm_vci, m,
                  EN_DQ_LEN(drq), sc->rxslot[slot].rxhand);
  #endif
  
  #ifdef ATM_PVCEXT
            /* if there's a subinterface for this vci, override ifp. */
            ifp = en_vci2ifp(sc, sc->rxslot[slot].atm_vci);
            ifp->if_ipackets++;
            m->m_pkthdr.rcvif = ifp;      /* XXX */
  #else
            ifp = &sc->enif;
            ifp->if_ipackets++;
  #endif
  
  #if NBPFILTER > 0
            if (ifp->if_bpf)
              BPF_MTAP(ifp, m);
  #endif
  
            atm_input(ifp, &ah, m, sc->rxslot[slot].rxhand);
          }
  
        }
        EN_WRAPADD(0, MID_DRQ_N, idx, 1);
      };
      sc->drq_chip = MID_DRQ_REG2A(val);  /* sync softc */
  
      if (sc->need_drqs) {        /* true if we had a DRQ shortage */
        need_softserv = 1;
        sc->need_drqs = 0;
  #ifdef EN_DEBUG
          printf("%s: cleared need DRQ condition\n", sc->sc_dev.dv_xname);
  #endif
      }
    }
  
    /*
     * handle service interrupts
     */
  
    if (reg & MID_INT_SERVICE) {
      chip = MID_SL_REG2A(EN_READ(sc, MID_SERV_WRITE));
  
      while (sc->hwslistp != chip) {
  
        /* fetch and remove it from hardware service list */
        vci = EN_READ(sc, sc->hwslistp);
        EN_WRAPADD(MID_SLOFF, MID_SLEND, sc->hwslistp, 4);/* advance hw ptr */
        slot = sc->rxvc2slot[vci];
        if (slot == RX_NONE) {
  #ifdef EN_DEBUG
          printf("%s: unexpected rx interrupt on VCI %d\n",
                  sc->sc_dev.dv_xname, vci);
  #endif
          EN_WRITE(sc, MID_VC(vci), MIDV_TRASH);  /* rx off, damn it! */
          continue;                               /* next */
        }
        EN_WRITE(sc, MID_VC(vci), sc->rxslot[slot].mode); /* remove from hwsl */
        EN_COUNT(sc->hwpull);
  
  #ifdef EN_DEBUG
        printf("%s: pulled VCI %d off hwslist\n", sc->sc_dev.dv_xname, vci);
  #endif
  
        /* add it to the software service list (if needed) */
        if ((sc->rxslot[slot].oth_flags & ENOTHER_SWSL) == 0) {
          EN_COUNT(sc->swadd);
          need_softserv = 1;
          sc->rxslot[slot].oth_flags |= ENOTHER_SWSL;
          sc->swslist[sc->swsl_tail] = slot;
          EN_WRAPADD(0, MID_SL_N, sc->swsl_tail, 1);
          sc->swsl_size++;
  #ifdef EN_DEBUG
        printf("%s: added VCI %d to swslist\n", sc->sc_dev.dv_xname, vci);
  #endif
        }
      };
    }
  
    /*
     * now service (function too big to include here)
     */
  
    if (need_softserv)
      en_service(sc);
  
    /*
     * keep our stats
     */
  
    if (reg & MID_INT_DMA_OVR) {
      EN_COUNT(sc->dmaovr);
  #ifdef EN_DEBUG
      printf("%s: MID_INT_DMA_OVR\n", sc->sc_dev.dv_xname);
  #endif
    }
    reg = EN_READ(sc, MID_STAT);
  #ifdef EN_STAT
    sc->otrash += MID_OTRASH(reg);
    sc->vtrash += MID_VTRASH(reg);
  #endif
  
    EN_INTR_RET(1); /* for us */
  }
  
  
  /*
   * en_service: handle a service interrupt
   *
   * Q: why do we need a software service list?
   *
   * A: if we remove a VCI from the hardware list and we find that we are
   *    out of DRQs we must defer processing until some DRQs become free.
   *    so we must remember to look at this RX VCI/slot later, but we can't
   *    put it back on the hardware service list (since that isn't allowed).
   *    so we instead save it on the software service list.   it would be nice
   *    if we could peek at the VCI on top of the hwservice list without removing
   *    it, however this leads to a race condition: if we peek at it and
   *    decide we are done with it new data could come in before we have a
   *    chance to remove it from the hwslist.   by the time we get it out of
   *    the list the interrupt for the new data will be lost.   oops!
   *
   */
  
  STATIC void en_service(sc)
  
  struct en_softc *sc;
  
  {
    struct mbuf *m, *tmp;
    u_int32_t cur, dstart, rbd, pdu, *sav, dma, bcode, count, *data, *datastop;
    u_int32_t start, stop, cnt, needalign;
    int slot, raw, aal5, vci, fill, mlen, tlen, drqneed, need, needfill, end;
  
    aal5 = 0;             /* Silence gcc */
  next_vci:
    if (sc->swsl_size == 0) {
  #ifdef EN_DEBUG
      printf("%s: en_service done\n", sc->sc_dev.dv_xname);
  #endif
      return;             /* >>> exit here if swsl now empty <<< */
    }
  
    /*
     * get slot/vci to service
     */
  
    slot = sc->swslist[sc->swsl_head];
    vci = sc->rxslot[slot].atm_vci;
  #ifdef EN_DIAG
    if (sc->rxvc2slot[vci] != slot) panic("en_service rx slot/vci sync");
  #endif
  
    /*
     * determine our mode and if we've got any work to do
     */
  
    raw = sc->rxslot[slot].oth_flags & ENOTHER_RAW;
    start= sc->rxslot[slot].start;
    stop= sc->rxslot[slot].stop;
    cur = sc->rxslot[slot].cur;
  
  #ifdef EN_DEBUG
    printf("%s: rx%d: service vci=%d raw=%d start/stop/cur=0x%x 0x%x 0x%x\n",
          sc->sc_dev.dv_xname, slot, vci, raw, start, stop, cur);
  #endif
  
  same_vci:
    dstart = MIDV_DSTART(EN_READ(sc, MID_DST_RP(vci)));
    dstart = (dstart * sizeof(u_int32_t)) + start;
  
    /* check to see if there is any data at all */
    if (dstart == cur) {
  defer:                                  /* defer processing */
      EN_WRAPADD(0, MID_SL_N, sc->swsl_head, 1);
      sc->rxslot[slot].oth_flags &= ~ENOTHER_SWSL;
      sc->swsl_size--;
                                          /* >>> remove from swslist <<< */
  #ifdef EN_DEBUG
      printf("%s: rx%d: remove vci %d from swslist\n",
                  sc->sc_dev.dv_xname, slot, vci);
  #endif
      goto next_vci;
    }
  
    /*
     * figure out how many bytes we need
     * [mlen = # bytes to go in mbufs, fill = # bytes to dump (MIDDMA_JK)]
     */
  
    if (raw) {
  
      /* raw mode (aka boodi mode) */
      fill = 0;
      if (dstart > cur)
        mlen = dstart - cur;
      else
        mlen = (dstart + (EN_RXSZ*1024)) - cur;
  
      if (mlen < sc->rxslot[slot].raw_threshold)
        goto defer;               /* too little data to deal with */
  
    } else {
  
      /* normal mode */
      aal5 = (sc->rxslot[slot].atm_flags & ATM_PH_AAL5);
      rbd = EN_READ(sc, cur);
      if (MID_RBD_ID(rbd) != MID_RBD_STDID)
        panic("en_service: id mismatch");
  
      if (rbd & MID_RBD_T) {
        mlen = 0;                 /* we've got trash */
        fill = MID_RBD_SIZE;
        EN_COUNT(sc->ttrash);
  #ifdef EN_DEBUG
        printf("RX overflow lost %d cells!\n", MID_RBD_CNT(rbd));
  #endif
      } else if (!aal5) {
        mlen = MID_RBD_SIZE + MID_CHDR_SIZE + MID_ATMDATASZ; /* 1 cell (ick!) */
        fill = 0;
      } else {
        struct ifnet *ifp;
  
        tlen = (MID_RBD_CNT(rbd) * MID_ATMDATASZ) + MID_RBD_SIZE;
        pdu = cur + tlen - MID_PDU_SIZE;
        if (pdu >= stop)
          pdu -= (EN_RXSZ*1024);
        pdu = EN_READ(sc, pdu);   /* get PDU in correct byte order */
        fill = tlen - MID_RBD_SIZE - MID_PDU_LEN(pdu);
        if (fill < 0 || (rbd & MID_RBD_CRCERR) != 0) {
          static int first = 1;
  
          if (first) {
            printf("%s: %s, dropping frame\n", sc->sc_dev.dv_xname,
                   (rbd & MID_RBD_CRCERR) ?
                   "CRC error" : "invalid AAL5 PDU length");
            printf("%s: got %d cells (%d bytes), AAL5 len is %d bytes (pdu=0x%x)\n",
                   sc->sc_dev.dv_xname, MID_RBD_CNT(rbd),
                   tlen - MID_RBD_SIZE, MID_PDU_LEN(pdu), pdu);
  #ifndef EN_DEBUG
            printf("CRC error report disabled from now on!\n");
            first = 0;
  #endif
          }
          fill = tlen;
  
  #ifdef ATM_PVCEXT
          ifp = en_vci2ifp(sc, vci);
  #else
          ifp = &sc->enif;
  #endif
          ifp->if_ierrors++;
  
        }
        mlen = tlen - fill;
      }
  
    }
  
    /*
     * now allocate mbufs for mlen bytes of data, if out of mbufs, trash all
     *
     * notes:
     *  1. it is possible that we've already allocated an mbuf for this pkt
     *     but ran out of DRQs, in which case we saved the allocated mbuf on
     *     "q".
     *  2. if we save an mbuf in "q" we store the "cur" (pointer) in the front
     *     of the mbuf as an identity (that we can check later), and we also
     *     store drqneed (so we don't have to recompute it).
     *  3. after this block of code, if m is still NULL then we ran out of mbufs
     */
  
    m = sc->rxslot[slot].q.ifq_head;
    drqneed = 1;
    if (m) {
      sav = mtod(m, u_int32_t *);
      if (sav[0] != cur) {
  #ifdef EN_DEBUG
        printf("%s: rx%d: q'ed mbuf %p not ours\n",
                  sc->sc_dev.dv_xname, slot, m);
  #endif
        m = NULL;                 /* wasn't ours */
        EN_COUNT(sc->rxqnotus);
      } else {
        EN_COUNT(sc->rxqus);
        IF_DEQUEUE(&sc->rxslot[slot].q, m);
        drqneed = sav[1];
  #ifdef EN_DEBUG
        printf("%s: rx%d: recovered q'ed mbuf %p (drqneed=%d)\n",
          sc->sc_dev.dv_xname, slot, m, drqneed);
  #endif
      }
    }
  
    if (mlen != 0 && m == NULL) {
      m = en_mget(sc, mlen, &drqneed);            /* allocate! */
      if (m == NULL) {
        fill += mlen;
        mlen = 0;
        EN_COUNT(sc->rxmbufout);
  #ifdef EN_DEBUG
        printf("%s: rx%d: out of mbufs\n", sc->sc_dev.dv_xname, slot);
  #endif
      }
  #ifdef EN_DEBUG
      printf("%s: rx%d: allocate mbuf %p, mlen=%d, drqneed=%d\n",
          sc->sc_dev.dv_xname, slot, m, mlen, drqneed);
  #endif
    }
  
  #ifdef EN_DEBUG
    printf("%s: rx%d: VCI %d, mbuf_chain %p, mlen %d, fill %d\n",
          sc->sc_dev.dv_xname, slot, vci, m, mlen, fill);
  #endif
  
    /*
     * now check to see if we've got the DRQs needed.    if we are out of
     * DRQs we must quit (saving our mbuf, if we've got one).
     */
  
    needfill = (fill) ? 1 : 0;
    if (drqneed + needfill > sc->drq_free) {
      sc->need_drqs = 1;  /* flag condition */
      if (m == NULL) {
        EN_COUNT(sc->rxoutboth);
  #ifdef EN_DEBUG
        printf("%s: rx%d: out of DRQs *and* mbufs!\n", sc->sc_dev.dv_xname, slot);
  #endif
        return;           /* >>> exit here if out of both mbufs and DRQs <<< */
      }
      sav = mtod(m, u_int32_t *);
      sav[0] = cur;
      sav[1] = drqneed;
      IF_ENQUEUE(&sc->rxslot[slot].q, m);
      EN_COUNT(sc->rxdrqout);
  #ifdef EN_DEBUG
      printf("%s: rx%d: out of DRQs\n", sc->sc_dev.dv_xname, slot);
  #endif
      return;             /* >>> exit here if out of DRQs <<< */
    }
  
    /*
     * at this point all resources have been allocated and we are commited
     * to servicing this slot.
     *
     * dma = last location we told chip about
     * cur = current location
     * mlen = space in the mbuf we want
     * need = bytes to xfer in (decrs to zero)
     * fill = how much fill we need
     * tlen = how much data to transfer to this mbuf
     * cnt/bcode/count = <same as xmit>
     *
     * 'needfill' not used after this point
     */
  
    dma = cur;            /* dma = last location we told chip about */
    need = roundup(mlen, sizeof(u_int32_t));
    fill = fill - (need - mlen);  /* note: may invalidate 'needfill' */
  
    for (tmp = m ; tmp != NULL && need > 0 ; tmp = tmp->m_next) {
      tlen = roundup(tmp->m_len, sizeof(u_int32_t)); /* m_len set by en_mget */
      data = mtod(tmp, u_int32_t *);
  
  #ifdef EN_DEBUG
      printf("%s: rx%d: load mbuf %p, m_len=%d, m_data=%p, tlen=%d\n",
          sc->sc_dev.dv_xname, slot, tmp, tmp->m_len, tmp->m_data, tlen);
  #endif
  
      /* copy data */
      if (EN_NORXDMA || !en_dma || tlen < EN_MINDMA) {
        datastop = (u_int32_t *)((u_char *) data + tlen);
        /* copy loop: preserve byte order!!!  use READDAT */
        while (data != datastop) {
          *data = EN_READDAT(sc, cur);
          data++;
          EN_WRAPADD(start, stop, cur, 4);
        }
        need -= tlen;
  #ifdef EN_DEBUG
        printf("%s: rx%d: vci%d: copied %d bytes (%d left)\n",
                  sc->sc_dev.dv_xname, slot, vci, tlen, need);
  #endif
        continue;
      }
  
      /* DMA data (check to see if we need to sync DRQ first) */
      if (dma != cur) {
        EN_DRQADD(sc, WORD_IDX(start,cur), vci, MIDDMA_JK, 0, 0, 0, 0);
  #ifdef EN_DEBUG
        printf("%s: rx%d: vci%d: drq_sync: advance pointer to %d\n",
                  sc->sc_dev.dv_xname, slot, vci, cur);
  #endif
      }
  
  #if !defined(MIDWAY_ENIONLY)
  
      /*
       * the adaptec DMA engine is smart and handles everything for us.
       */
  
      if (sc->is_adaptec) {
        need -= tlen;
        EN_WRAPADD(start, stop, cur, tlen);
  #ifdef EN_DEBUG
        printf("%s: rx%d: vci%d: adp_dma %d bytes (%d left)\n",
                  sc->sc_dev.dv_xname, slot, vci, tlen, need);
  #endif
        end = (need == 0 && !fill) ? MID_DMA_END : 0;
        EN_DRQADD(sc, tlen, vci, 0, vtophys((vaddr_t)data), mlen, slot, end);
        if (end)
          goto done;
        dma = cur;        /* update DMA pointer */
        continue;
      }
  #endif /* !MIDWAY_ENIONLY */
  
  
  #if !defined(MIDWAY_ADPONLY)
  
      /*
       * the ENI DMA engine is not so smart and need more help from us
       */
  
      /* do we need to do a DMA op to align? */
      if (sc->alburst &&
        (needalign = (((unsigned long) data) & sc->bestburstmask)) != 0) {
        cnt = sc->bestburstlen - needalign;
        if (cnt > tlen) {
          cnt = tlen;
          count = cnt / sizeof(u_int32_t);
          bcode = MIDDMA_WORD;
        } else {
          count = cnt / sizeof(u_int32_t);
          bcode = en_dmaplan[count].bcode;
          count = cnt >> en_dmaplan[count].divshift;
        }
        need -= cnt;
        EN_WRAPADD(start, stop, cur, cnt);
  #ifdef EN_DEBUG
        printf("%s: rx%d: vci%d: al_dma %d bytes (%d left)\n",
                  sc->sc_dev.dv_xname, slot, vci, cnt, need);
  #endif
        tlen -= cnt;
        end = (need == 0 && !fill) ? MID_DMA_END : 0;
        EN_DRQADD(sc, count, vci, bcode, vtophys((vaddr_t)data), mlen, slot, end);
        if (end)
          goto done;
        data = (u_int32_t *)((u_char *) data + cnt);
      }
  
      /* do we need a max-sized burst? */
      if (tlen >= sc->bestburstlen) {
        count = tlen >> sc->bestburstshift;
        cnt = count << sc->bestburstshift;
        bcode = sc->bestburstcode;
        need -= cnt;
        EN_WRAPADD(start, stop, cur, cnt);
  #ifdef EN_DEBUG
        printf("%s: rx%d: vci%d: best_dma %d bytes (%d left)\n",
                  sc->sc_dev.dv_xname, slot, vci, cnt, need);
  #endif
        tlen -= cnt;
        end = (need == 0 && !fill) ? MID_DMA_END : 0;
        EN_DRQADD(sc, count, vci, bcode, vtophys((vaddr_t)data), mlen, slot, end);
        if (end)
          goto done;
        data = (u_int32_t *)((u_char *) data + cnt);
      }
  
      /* do we need to do a cleanup burst? */
      if (tlen) {
        count = tlen / sizeof(u_int32_t);
        bcode = en_dmaplan[count].bcode;
        count = tlen >> en_dmaplan[count].divshift;
        need -= tlen;
        EN_WRAPADD(start, stop, cur, tlen);
  #ifdef EN_DEBUG
        printf("%s: rx%d: vci%d: cleanup_dma %d bytes (%d left)\n",
                  sc->sc_dev.dv_xname, slot, vci, tlen, need);
  #endif
        end = (need == 0 && !fill) ? MID_DMA_END : 0;
        EN_DRQADD(sc, count, vci, bcode, vtophys((vaddr_t)data), mlen, slot, end);
        if (end)
          goto done;
      }
  
      dma = cur;          /* update DMA pointer */
  
  #endif /* !MIDWAY_ADPONLY */
  
    }
  
    /* skip the end */
    if (fill || dma != cur) {
  #ifdef EN_DEBUG
        if (fill)
          printf("%s: rx%d: vci%d: skipping %d bytes of fill\n",
                  sc->sc_dev.dv_xname, slot, vci, fill);
        else
          printf("%s: rx%d: vci%d: syncing chip from 0x%x to 0x%x [cur]\n",
                  sc->sc_dev.dv_xname, slot, vci, dma, cur);
  #endif
      EN_WRAPADD(start, stop, cur, fill);
      EN_DRQADD(sc, WORD_IDX(start,cur), vci, MIDDMA_JK, 0, mlen,
                                          slot, MID_DMA_END);
      /* dma = cur; */    /* not necessary since we are done */
    }
  
    /*
     * done, remove stuff we don't want to pass up:
     *   raw mode (boodi mode): pass everything up for later processing
     *   aal5: remove RBD
     *   aal0: remove RBD + cell header
     */
  
  done:
    if (m) {
      if (!raw) {
        cnt = MID_RBD_SIZE;
        if (!aal5) cnt += MID_CHDR_SIZE;
        m->m_len -= cnt;                          /* chop! */
        m->m_pkthdr.len -= cnt;
        m->m_data += cnt;
      }
      IF_ENQUEUE(&sc->rxslot[slot].indma, m);
    }
    sc->rxslot[slot].cur = cur;           /* update master copy of 'cur' */
  
  #ifdef EN_DEBUG
    printf("%s: rx%d: vci%d: DONE!   cur now =0x%x\n",
          sc->sc_dev.dv_xname, slot, vci, cur);
  #endif
  
    goto same_vci;        /* get next packet in this slot */
  }
  
  
  #ifdef EN_DDBHOOK
  /*
   * functions we can call from ddb
   */
  
  /*
   * en_dump: dump the state
   */
  
  #define END_SWSL        0x00000040              /* swsl state */
  #define END_DRQ         0x00000020              /* drq state */
  #define END_DTQ         0x00000010              /* dtq state */
  #define END_RX          0x00000008              /* rx state */
  #define END_TX          0x00000004              /* tx state */
  #define END_MREGS       0x00000002              /* registers */
  #define END_STATS       0x00000001              /* dump stats */
  
  #define END_BITS "\2\7SWSL\6DRQ\5DTQ\4RX\3TX\2MREGS\1STATS"
  
  int en_dump(unit, level)
  
  int unit, level;
  
  {
    struct en_softc *sc;
    int lcv, cnt, slot;
    u_int32_t ptr, reg;
  
    for (lcv = 0 ; lcv < en_cd.cd_ndevs ; lcv++) {
      char sbuf[256];
  
      sc = device_lookup(&en_cd, lcv);
      if (sc == NULL) continue;
      if (unit != -1 && unit != lcv)
        continue;
  
      bitmask_snprintf(level, END_BITS, sbuf, sizeof(sbuf));
      printf("dumping device %s at level 0x%s\n", sc->sc_dev.dv_xname, sbuf);
  
      if (sc->dtq_us == 0) {
        printf("<hasn't been en_init'd yet>\n");
        continue;
      }
  
      if (level & END_STATS) {
        printf("  en_stats:\n");
        printf("    %d mfix (%d failed); %d/%d head/tail byte DMAs, %d flushes\n",
             sc->mfix, sc->mfixfail, sc->headbyte, sc->tailbyte, sc->tailflush);
        printf("    %d rx DMA overflow interrupts\n", sc->dmaovr);
        printf("    %d times we ran out of TX space and stalled\n",
                                                          sc->txoutspace);
        printf("    %d times we ran out of DTQs\n", sc->txdtqout);
        printf("    %d times we launched a packet\n", sc->launch);
        printf("    %d times we launched without on-board header\n", sc->lheader);
        printf("    %d times we launched without on-board tail\n", sc->ltail);
        printf("    %d times we pulled the hw service list\n", sc->hwpull);
        printf("    %d times we pushed a vci on the sw service list\n",
                                                                  sc->swadd);
        printf("    %d times RX pulled an mbuf from Q that wasn't ours\n",
                                                           sc->rxqnotus);
        printf("    %d times RX pulled a good mbuf from Q\n", sc->rxqus);
        printf("    %d times we ran out of mbufs *and* DRQs\n", sc->rxoutboth);
        printf("    %d times we ran out of DRQs\n", sc->rxdrqout);
  
        printf("    %d transmit packets dropped due to mbsize\n", sc->txmbovr);
        printf("    %d cells trashed due to turned off rxvc\n", sc->vtrash);
        printf("    %d cells trashed due to totally full buffer\n", sc->otrash);
        printf("    %d cells trashed due almost full buffer\n", sc->ttrash);
        printf("    %d rx mbuf allocation failures\n", sc->rxmbufout);
  #ifdef NATM
        printf("    %d drops at natmintrq\n", natmintrq.ifq_drops);
  #ifdef NATM_STAT
        printf("    natmintr so_rcv: ok/drop cnt: %d/%d, ok/drop bytes: %d/%d\n",
          natm_sookcnt, natm_sodropcnt, natm_sookbytes, natm_sodropbytes);
  #endif
  #endif
      }
  
      if (level & END_MREGS) {
        char sbuf[256];
  
        printf("mregs:\n");
        printf("resid = 0x%x\n", EN_READ(sc, MID_RESID));
  
        bitmask_snprintf(EN_READ(sc, MID_INTSTAT), MID_INTBITS, sbuf, sizeof(sbuf));
        printf("interrupt status = 0x%s\n", sbuf);
  
        bitmask_snprintf(EN_READ(sc, MID_INTENA), MID_INTBITS, sbuf, sizeof(sbuf));
        printf("interrupt enable = 0x%s\n", sbuf);
  
        bitmask_snprintf(EN_READ(sc, MID_MAST_CSR), MID_MCSRBITS, sbuf, sizeof(sbuf));
        printf("mcsr = 0x%s\n", sbuf);
  
        printf("serv_write = [chip=%d] [us=%d]\n", EN_READ(sc, MID_SERV_WRITE),
                          MID_SL_A2REG(sc->hwslistp));
        printf("DMA addr = 0x%x\n", EN_READ(sc, MID_DMA_ADDR));
        printf("DRQ: chip[rd=0x%x,wr=0x%x], sc[chip=0x%x,us=0x%x]\n",
          MID_DRQ_REG2A(EN_READ(sc, MID_DMA_RDRX)),
          MID_DRQ_REG2A(EN_READ(sc, MID_DMA_WRRX)), sc->drq_chip, sc->drq_us);
        printf("DTQ: chip[rd=0x%x,wr=0x%x], sc[chip=0x%x,us=0x%x]\n",
          MID_DTQ_REG2A(EN_READ(sc, MID_DMA_RDTX)),
          MID_DTQ_REG2A(EN_READ(sc, MID_DMA_WRTX)), sc->dtq_chip, sc->dtq_us);
  
        printf("  unusal txspeeds: ");
        for (cnt = 0 ; cnt < MID_N_VC ; cnt++)
          if (sc->txspeed[cnt])
            printf(" vci%d=0x%x", cnt, sc->txspeed[cnt]);
        printf("\n");
  
        printf("  rxvc slot mappings: ");
        for (cnt = 0 ; cnt < MID_N_VC ; cnt++)
          if (sc->rxvc2slot[cnt] != RX_NONE)
            printf("  %d->%d", cnt, sc->rxvc2slot[cnt]);
        printf("\n");
  
      }
  
      if (level & END_TX) {
        printf("tx:\n");
        for (slot = 0 ; slot < EN_NTX; slot++) {
          printf("tx%d: start/stop/cur=0x%x/0x%x/0x%x [%d]  ", slot,
            sc->txslot[slot].start, sc->txslot[slot].stop, sc->txslot[slot].cur,
                  (sc->txslot[slot].cur - sc->txslot[slot].start)/4);
          printf("mbsize=%d, bfree=%d\n", sc->txslot[slot].mbsize,
                  sc->txslot[slot].bfree);
          printf("txhw: base_address=0x%lx, size=%d, read=%d, descstart=%d\n",
            (u_long)MIDX_BASE(EN_READ(sc, MIDX_PLACE(slot))),
            MIDX_SZ(EN_READ(sc, MIDX_PLACE(slot))),
            EN_READ(sc, MIDX_READPTR(slot)), EN_READ(sc, MIDX_DESCSTART(slot)));
        }
      }
  
      if (level & END_RX) {
        printf("  recv slots:\n");
        for (slot = 0 ; slot < sc->en_nrx; slot++) {
          printf("rx%d: vci=%d: start/stop/cur=0x%x/0x%x/0x%x ", slot,
            sc->rxslot[slot].atm_vci, sc->rxslot[slot].start,
            sc->rxslot[slot].stop, sc->rxslot[slot].cur);
          printf("mode=0x%x, atm_flags=0x%x, oth_flags=0x%x\n",
          sc->rxslot[slot].mode, sc->rxslot[slot].atm_flags,
                  sc->rxslot[slot].oth_flags);
          printf("RXHW: mode=0x%x, DST_RP=0x%x, WP_ST_CNT=0x%x\n",
            EN_READ(sc, MID_VC(sc->rxslot[slot].atm_vci)),
            EN_READ(sc, MID_DST_RP(sc->rxslot[slot].atm_vci)),
            EN_READ(sc, MID_WP_ST_CNT(sc->rxslot[slot].atm_vci)));
        }
      }
  
      if (level & END_DTQ) {
        printf("  dtq [need_dtqs=%d,dtq_free=%d]:\n",
                                          sc->need_dtqs, sc->dtq_free);
        ptr = sc->dtq_chip;
        while (ptr != sc->dtq_us) {
          reg = EN_READ(sc, ptr);
          printf("\t0x%x=[cnt=%d, chan=%d, end=%d, type=%d @ 0x%x]\n",
              sc->dtq[MID_DTQ_A2REG(ptr)], MID_DMA_CNT(reg), MID_DMA_TXCHAN(reg),
              (reg & MID_DMA_END) != 0, MID_DMA_TYPE(reg), EN_READ(sc, ptr+4));
          EN_WRAPADD(MID_DTQOFF, MID_DTQEND, ptr, 8);
        }
      }
  
      if (level & END_DRQ) {
        printf("  drq [need_drqs=%d,drq_free=%d]:\n",
                                          sc->need_drqs, sc->drq_free);
        ptr = sc->drq_chip;
        while (ptr != sc->drq_us) {
          reg = EN_READ(sc, ptr);
          printf("\t0x%x=[cnt=%d, chan=%d, end=%d, type=%d @ 0x%x]\n",
            sc->drq[MID_DRQ_A2REG(ptr)], MID_DMA_CNT(reg), MID_DMA_RXVCI(reg),
            (reg & MID_DMA_END) != 0, MID_DMA_TYPE(reg), EN_READ(sc, ptr+4));
          EN_WRAPADD(MID_DRQOFF, MID_DRQEND, ptr, 8);
        }
      }
  
      if (level & END_SWSL) {
        printf(" swslist [size=%d]: ", sc->swsl_size);
        for (cnt = sc->swsl_head ; cnt != sc->swsl_tail ;
                          cnt = (cnt + 1) % MID_SL_N)
          printf("0x%x ", sc->swslist[cnt]);
        printf("\n");
      }
    }
    return(0);
  }
  
  /*
   * en_dumpmem: dump the memory
   */
  
  int en_dumpmem(unit, addr, len)
  
  int unit, addr, len;
  
  {
    struct en_softc *sc;
    u_int32_t reg;
  
    sc = device_lookup(&en_cd, unit);
    if (sc == NULL) {
      printf("invalid unit number: %d\n", unit);
      return(0);
    }
    addr = addr & ~3;
    if (addr < MID_RAMOFF || addr + len*4 > MID_MAXOFF || len <= 0) {
      printf("invalid addr/len number: %d, %d\n", addr, len);
      return(0);
    }
    printf("dumping %d words starting at offset 0x%x\n", len, addr);
    while (len--) {
      reg = EN_READ(sc, addr);
      printf("mem[0x%x] = 0x%x\n", addr, reg);
      addr += 4;
    }
    return(0);
  }
  #endif
  
  #ifdef ATM_PVCEXT
  /*
   * ATM PVC extension: shaper control and pvc subinterfaces
   */
  
  /*
   * the list of the interfaces sharing the physical device.
   * in order to avoid starvation, the interfaces are scheduled in
   * a round-robin fashion when en_start is called from tx complete
   * interrupts.
   */
  static void rrp_add(sc, ifp)
          struct en_softc *sc;
          struct ifnet *ifp;
  {
          struct rrp *head, *p, *new;
  
          head = sc->txrrp;
          if ((p = head) != NULL) {
                  while (1) {
                          if (p->ifp == ifp) {
                                  /* an entry for this ifp already exits */
                                  p->nref++;
                                  return;
                          }
                          if (p->next == head)
                                  break;
                          p = p->next;
                  }
          }
  
          /* create a new entry */
          MALLOC(new, struct rrp *, sizeof(struct rrp), M_DEVBUF, M_WAITOK);
          if (new == NULL) {
                  printf("en_rrp_add: malloc failed!\n");
                  return;
          }
  
          new->ifp = ifp;
          new->nref = 1;
  
          if (p == NULL) {
                  /* this is the only one in the list */
                  new->next = new;
                  sc->txrrp = new;
          }
          else {
                  /* add the new entry at the tail of the list */
                  new->next = p->next;
                  p->next = new;
          }
  }
  
  #if 0 /* not used */
  static void rrp_delete(sc, ifp)
          struct en_softc *sc;
          struct ifnet *ifp;
  {
          struct rrp *head, *p, *prev;
  
          head = sc->txrrp;
  
          prev = head;
          if (prev == NULL) {
                  printf("rrp_delete: no list!\n");
                  return;
          }
          p = prev->next;
  
          while (1) {
                  if (p->ifp == ifp) {
                          p->nref--;
                          if (p->nref > 0)
                                  return;
                          /* remove this entry */
                          if (p == prev) {
                                  /* this is the only entry in the list */
                                  sc->txrrp = NULL;
                          }
                          else {
                                  prev->next = p->next;
                                  if (head == p)
                                          sc->txrrp = p->next;
                          }
                          FREE(p, M_DEVBUF);
                  }
                  prev = p;
                  p = prev->next;
                  if (prev == head) {
                          printf("rrp_delete: no matching entry!\n");
                          return;
                  }
          }
  }
  #endif
  
  static struct ifnet *
  en_vci2ifp(sc, vci)
          struct en_softc *sc;
          int vci;
  {
          struct pvcsif *pvcsif;
  
          LIST_FOREACH(pvcsif, &sc->sif_list, sif_links) {
                  if (vci == pvcsif->sif_vci)
                          return (&pvcsif->sif_if);
          }
          return (&sc->enif);
  }
  
  /*
   * create and attach per pvc subinterface
   * (currently detach is not supported)
   */
  static struct ifnet *
  en_pvcattach(ifp)
          struct ifnet *ifp;
  {
          struct en_softc *sc = (struct en_softc *) ifp->if_softc;
          struct ifnet *pvc_ifp;
          int s;
  
          if ((pvc_ifp = pvcsif_alloc()) == NULL)
                  return (NULL);
  
          pvc_ifp->if_softc = sc;
          pvc_ifp->if_ioctl = en_ioctl;
          pvc_ifp->if_start = en_start;
          pvc_ifp->if_flags = (IFF_POINTOPOINT|IFF_MULTICAST) |
                  (ifp->if_flags & (IFF_RUNNING|IFF_SIMPLEX|IFF_NOTRAILERS));
  
          s = splnet();
          LIST_INSERT_HEAD(&sc->sif_list, (struct pvcsif *)pvc_ifp, sif_links);
          if_attach(pvc_ifp);
          atm_ifattach(pvc_ifp);
  
  #ifdef ATM_PVCEXT
          rrp_add(sc, pvc_ifp);
  #endif
          splx(s);
  
          return (pvc_ifp);
  }
  
  
  /* txspeed conversion derived from linux drivers/atm/eni.c
     by Werner Almesberger, EPFL LRC */
  static const int pre_div[] = { 4,16,128,2048 };
  
  static int en_pcr2txspeed(pcr)
          int pcr;
  {
          int pre, res, div;
  
          if (pcr == 0 || pcr > 347222)
                  pre = res = 0;  /* max rate */
          else {
                  for (pre = 0; pre < 3; pre++)
                          if (25000000/pre_div[pre]/64 <= pcr)
                                  break;
                  div = pre_div[pre]*(pcr);
  #if 1
                  /*
                   * the shaper value should be rounded down,
                   * instead of rounded up.
                   * (which means "res" should be rounded up.)
                   */
                  res = (25000000 + div -1)/div - 1;
  #else
                  res = 25000000/div-1;
  #endif
                  if (res < 0)
                          res = 0;
                  if (res > 63)
                          res = 63;
          }
          return ((pre << 6) + res);
  }
  
  static int en_txspeed2pcr(txspeed)
          int txspeed;
  {
          int pre, res, pcr;
  
          pre = (txspeed >> 6) & 0x3;
          res = txspeed & 0x3f;
          pcr = 25000000 / pre_div[pre] / (res+1);
          return (pcr);
  }
  
  /*
   * en_txctl selects a hardware transmit channel and sets the shaper value.
   * en_txctl should be called after enabling the vc by en_rxctl
   * since it assumes a transmit channel is already assigned by en_rxctl
   * to the vc.
   */
  static int en_txctl(sc, vci, joint_vci, pcr)
          struct en_softc *sc;
          int vci;
          int joint_vci;
          int pcr;
  {
          int txspeed, txchan, s;
  
          if (pcr)
                  txspeed = en_pcr2txspeed(pcr);
          else
                  txspeed = 0;
  
          s = splnet();
          txchan = sc->txvc2slot[vci];
          sc->txslot[txchan].nref--;
  
          /* select a slot */
          if (joint_vci != 0)
                  /* use the same channel */
                  txchan = sc->txvc2slot[joint_vci];
          else if (pcr == 0)
                  txchan = 0;
          else {
                  for (txchan = 1; txchan < EN_NTX; txchan++) {
                          if (sc->txslot[txchan].nref == 0)
                                  break;
                  }
          }
          if (txchan == EN_NTX) {
  #if 1
                  /* no free slot! */
                  splx(s);
                  return (ENOSPC);
  #else
                  /*
                   * to allow multiple vc's to share a slot,
                   * use a slot with the smallest reference count
                   */
                  int slot = 1;
                  txchan = 1;
                  for (slot = 2; slot < EN_NTX; slot++)
                          if (sc->txslot[slot].nref < sc->txslot[txchan].nref)
                                  txchan = slot;
  #endif
          }
  
          sc->txvc2slot[vci] = txchan;
          sc->txslot[txchan].nref++;
  
          /* set the shaper parameter */
          sc->txspeed[vci] = (u_int8_t)txspeed;
  
          splx(s);
  #ifdef EN_DEBUG
          printf("VCI:%d PCR set to %d, tx channel %d\n", vci, pcr, txchan);
          if (joint_vci != 0)
                  printf("  slot shared with VCI:%d\n", joint_vci);
  #endif
          return (0);
  }
  
  static int en_pvctx(sc, pvcreq)
          struct en_softc *sc;
          struct pvctxreq *pvcreq;
  {
          struct ifnet *ifp;
          struct atm_pseudoioctl api;
          struct atm_pseudohdr *pvc_aph, *pvc_joint;
          int vci, joint_vci, pcr;
          int error = 0;
  
          /* check vpi:vci values */
          pvc_aph = &pvcreq->pvc_aph;
          pvc_joint = &pvcreq->pvc_joint;
  
          vci = ATM_PH_VCI(pvc_aph);
          joint_vci = ATM_PH_VCI(pvc_joint);
          pcr = pvcreq->pvc_pcr;
  
          if (ATM_PH_VPI(pvc_aph) != 0 || vci >= MID_N_VC ||
              ATM_PH_VPI(pvc_joint) != 0 || joint_vci >= MID_N_VC)
                  return (EADDRNOTAVAIL);
  
          if ((ifp = ifunit(pvcreq->pvc_ifname)) == NULL)
                  return (ENXIO);
  
          if (pcr < 0) {
                  /* negative pcr means disable the vc. */
                  if (sc->rxvc2slot[vci] == RX_NONE)
                          /* already disabled */
                          return 0;
  
                  ATM_PH_FLAGS(&api.aph) = 0;
                  ATM_PH_VPI(&api.aph) = 0;
                  ATM_PH_SETVCI(&api.aph, vci);
                  api.rxhand = NULL;
  
                  error = en_rxctl(sc, &api, 0);
  
                  if (error == 0 && &sc->enif != ifp) {
                          /* clear vc info of this subinterface */
                          struct pvcsif *pvcsif = (struct pvcsif *)ifp;
  
                          ATM_PH_SETVCI(&api.aph, 0);
                          pvcsif->sif_aph = api.aph;
                          pvcsif->sif_vci = 0;
                  }
                  return (error);
          }
  
          if (&sc->enif == ifp) {
                  /* called for an en interface */
                  if (sc->rxvc2slot[vci] == RX_NONE) {
                          /* vc is not active */
  #ifdef __NetBSD__
                          printf("%s: en_pvctx: rx not active! vci=%d\n",
                                 ifp->if_xname, vci);
  #else
                          printf("%s%d: en_pvctx: rx not active! vci=%d\n",
                                 ifp->if_name, ifp->if_unit, vci);
  #endif
                          return (EINVAL);
                  }
          }
          else {
                  /* called for a pvc subinterface */
                  struct pvcsif *pvcsif = (struct pvcsif *)ifp;
  
  #ifdef __NetBSD__
                  strlcpy(pvcreq->pvc_ifname, sc->enif.if_xname,
                      sizeof(pvcreq->pvc_ifname));
  #else
                  snprintf(pvcreq->pvc_ifname, sizeof(pvcreq->pvc_ifname), "%s%d",
                      sc->enif.if_name, sc->enif.if_unit);
  #endif
                  ATM_PH_FLAGS(&api.aph) =
                          (ATM_PH_FLAGS(pvc_aph) & (ATM_PH_AAL5|ATM_PH_LLCSNAP));
                  ATM_PH_VPI(&api.aph) = 0;
                  ATM_PH_SETVCI(&api.aph, vci);
                  api.rxhand = NULL;
                  pvcsif->sif_aph = api.aph;
                  pvcsif->sif_vci = ATM_PH_VCI(&api.aph);
  
                  if (sc->rxvc2slot[vci] == RX_NONE) {
                          /* vc is not active, enable rx */
                          error = en_rxctl(sc, &api, 1);
                          if (error)
                                  return error;
                  }
                  else {
                          /* vc is already active, update aph in softc */
                          sc->rxslot[sc->rxvc2slot[vci]].atm_flags =
                                  ATM_PH_FLAGS(&api.aph);
                  }
          }
  
          error = en_txctl(sc, vci, joint_vci, pcr);
  
          if (error == 0) {
                  if (sc->txspeed[vci] != 0)
                          pvcreq->pvc_pcr = en_txspeed2pcr(sc->txspeed[vci]);
                  else
                          pvcreq->pvc_pcr = 0;
          }
  
          return error;
  }
  
  static int en_pvctxget(sc, pvcreq)
          struct en_softc *sc;
          struct pvctxreq *pvcreq;
  {
          struct pvcsif *pvcsif;
          struct ifnet *ifp;
          int vci, slot;
  
          if ((ifp = ifunit(pvcreq->pvc_ifname)) == NULL)
                  return (ENXIO);
  
          if (ifp == &sc->enif) {
                  /* physical interface: assume vci is specified */
                  struct atm_pseudohdr *pvc_aph;
  
                  pvc_aph = &pvcreq->pvc_aph;
                  vci = ATM_PH_VCI(pvc_aph);
                  if ((slot = sc->rxvc2slot[vci]) == RX_NONE)
                          ATM_PH_FLAGS(pvc_aph) = 0;
                  else
                          ATM_PH_FLAGS(pvc_aph) = sc->rxslot[slot].atm_flags;
                  ATM_PH_VPI(pvc_aph) = 0;
          }
          else {
                  /* pvc subinterface */
  #ifdef __NetBSD__
                  strlcpy(pvcreq->pvc_ifname, sc->enif.if_xname,
                      sizeof(pvcreq->pvc_ifname));
  #else
                  snprintf(pvcreq->pvc_ifname, sizeof(pvcreq->pvc_ifname), "%s%d",
                      sc->enif.if_name, sc->enif.if_unit);
  #endif
  
                  pvcsif = (struct pvcsif *)ifp;
                  pvcreq->pvc_aph = pvcsif->sif_aph;
                  vci = pvcsif->sif_vci;
          }
  
          if ((slot = sc->rxvc2slot[vci]) == RX_NONE) {
                  /* vc is not active */
                  ATM_PH_FLAGS(&pvcreq->pvc_aph) = 0;
                  pvcreq->pvc_pcr = -1;
          }
          else if (sc->txspeed[vci])
                  pvcreq->pvc_pcr = en_txspeed2pcr(sc->txspeed[vci]);
          else
                  pvcreq->pvc_pcr = 0;
  
          return (0);
  }
  
  #endif /* ATM_PVCEXT */
  
  #endif /* NEN > 0 || !defined(__FreeBSD__) */