sys/dev/netif/plip/if_plip.c

   1 /*-
   2  * Copyright (c) 1997 Poul-Henning Kamp
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  *      From Id: lpt.c,v 1.55.2.1 1996/11/12 09:08:38 phk Exp
  27  * $FreeBSD: src/sys/dev/ppbus/if_plip.c,v 1.19.2.1 2000/05/24 00:20:57 n_hibma Exp $
  28  * $DragonFly: src/sys/dev/netif/plip/if_plip.c,v 1.19 2006/12/23 00:26:21 swildner Exp $
  29  */
  30
  31 /*
  32  * Parallel port TCP/IP interfaces added.  I looked at the driver from
  33  * MACH but this is a complete rewrite, and btw. incompatible, and it
  34  * should perform better too.  I have never run the MACH driver though.
  35  *
  36  * This driver sends two bytes (0x08, 0x00) in front of each packet,
  37  * to allow us to distinguish another format later.
  38  *
  39  * Now added an Linux/Crynwr compatibility mode which is enabled using
  40  * IF_LINK0 - Tim Wilkinson.
  41  *
  42  * TODO:
  43  *    Make HDLC/PPP mode, use IF_LLC1 to enable.
  44  *
  45  * Connect the two computers using a Laplink parallel cable to use this
  46  * feature:
  47  *
  48  *      +----------------------------------------+
  49  *      |A-name A-End   B-End   Descr.  Port/Bit |
  50  *      +----------------------------------------+
  51  *      |DATA0  2       15      Data    0/0x01   |
  52  *      |-ERROR 15      2               1/0x08   |
  53  *      +----------------------------------------+
  54  *      |DATA1  3       13      Data    0/0x02   |
  55  *      |+SLCT  13      3               1/0x10   |
  56  *      +----------------------------------------+
  57  *      |DATA2  4       12      Data    0/0x04   |
  58  *      |+PE    12      4               1/0x20   |
  59  *      +----------------------------------------+
  60  *      |DATA3  5       10      Strobe  0/0x08   |
  61  *      |-ACK   10      5               1/0x40   |
  62  *      +----------------------------------------+
  63  *      |DATA4  6       11      Data    0/0x10   |
  64  *      |BUSY   11      6               1/~0x80  |
  65  *      +----------------------------------------+
  66  *      |GND    18-25   18-25   GND     -        |
  67  *      +----------------------------------------+
  68  *
  69  * Expect transfer-rates up to 75 kbyte/sec.
  70  *
  71  * If GCC could correctly grok
  72  *      register int port asm("edx")
  73  * the code would be cleaner
  74  *
  75  * Poul-Henning Kamp <phk@freebsd.org>
  76  */
  77
  78 /*
  79  * Update for ppbus, PLIP support only - Nicolas Souchu
  80  */
  81
  82 #include "opt_plip.h"
  83
  84 #include <sys/param.h>
  85 #include <sys/systm.h>
  86 #include <sys/module.h>
  87 #include <sys/bus.h>
  88 #include <sys/mbuf.h>
  89 #include <sys/socket.h>
  90 #include <sys/sockio.h>
  91 #include <sys/kernel.h>
  92 #include <sys/malloc.h>
  93 #include <sys/rman.h>
  94 #include <sys/thread2.h>
  95
  96 #include <machine/clock.h>
  97
  98 #include <net/if.h>
  99 #include <net/ifq_var.h>
 100 #include <net/if_types.h>
 101 #include <net/netisr.h>
 102
 103 #include <netinet/in.h>
 104 #include <netinet/in_var.h>
 105
 106 #include <net/bpf.h>
 107
 108 #include <bus/ppbus/ppbconf.h>
 109 #include "ppbus_if.h"
 110 #include <bus/ppbus/ppbio.h>
 111
 112 #ifndef LPMTU                   /* MTU for the lp# interfaces */
 113 #define LPMTU   1500
 114 #endif
 115
 116 #ifndef LPMAXSPIN1              /* DELAY factor for the lp# interfaces */
 117 #define LPMAXSPIN1      8000   /* Spinning for remote intr to happen */
 118 #endif
 119
 120 #ifndef LPMAXSPIN2              /* DELAY factor for the lp# interfaces */
 121 #define LPMAXSPIN2      500     /* Spinning for remote handshake to happen */
 122 #endif
 123
 124 #ifndef LPMAXERRS               /* Max errors before !RUNNING */
 125 #define LPMAXERRS       100
 126 #endif
 127
 128 #define CLPIPHDRLEN     14      /* We send dummy ethernet addresses (two) + packet type in front of packet */
 129 #define CLPIP_SHAKE     0x80    /* This bit toggles between nibble reception */
 130 #define MLPIPHDRLEN     CLPIPHDRLEN
 131
 132 #define LPIPHDRLEN      2       /* We send 0x08, 0x00 in front of packet */
 133 #define LPIP_SHAKE      0x40    /* This bit toggles between nibble reception */
 134 #if !defined(MLPIPHDRLEN) || LPIPHDRLEN > MLPIPHDRLEN
 135 #define MLPIPHDRLEN     LPIPHDRLEN
 136 #endif
 137
 138 #define LPIPTBLSIZE     256     /* Size of octet translation table */
 139
 140 #define lprintf         if (lptflag) kprintf
 141
 142 #ifdef PLIP_DEBUG
 143 static int volatile lptflag = 1;
 144 #else
 145 static int volatile lptflag = 0;
 146 #endif
 147
 148 struct lp_data {
 149         unsigned short lp_unit;
 150
 151         struct  ifnet   sc_if;
 152         u_char          *sc_ifbuf;
 153         int             sc_iferrs;
 154
 155         struct resource *res_irq;
 156 };
 157
 158 /* Tables for the lp# interface */
 159 static u_char *txmith;
 160 #define txmitl (txmith+(1*LPIPTBLSIZE))
 161 #define trecvh (txmith+(2*LPIPTBLSIZE))
 162 #define trecvl (txmith+(3*LPIPTBLSIZE))
 163
 164 static u_char *ctxmith;
 165 #define ctxmitl (ctxmith+(1*LPIPTBLSIZE))
 166 #define ctrecvh (ctxmith+(2*LPIPTBLSIZE))
 167 #define ctrecvl (ctxmith+(3*LPIPTBLSIZE))
 168
 169 /* Functions for the lp# interface */
 170 static int lpinittables(void);
 171 static int lpioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
 172 static int lpoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
 173         struct rtentry *);
 174 static void lp_intr(void *);
 175
 176 #define DEVTOSOFTC(dev) \
 177         ((struct lp_data *)device_get_softc(dev))
 178 #define UNITOSOFTC(unit) \
 179         ((struct lp_data *)devclass_get_softc(lp_devclass, (unit)))
 180 #define UNITODEVICE(unit) \
 181         (devclass_get_device(lp_devclass, (unit)))
 182
 183 static devclass_t lp_devclass;
 184
 185 /*
 186  * lpprobe()
 187  */
 188 static int
 189 lp_probe(device_t dev)
 190 {
 191         device_t ppbus = device_get_parent(dev);
 192         struct lp_data *lp;
 193         int zero = 0;
 194         uintptr_t irq;
 195
 196         lp = DEVTOSOFTC(dev);
 197
 198         /* retrieve the ppbus irq */
 199         BUS_READ_IVAR(ppbus, dev, PPBUS_IVAR_IRQ, &irq);
 200
 201         /* if we haven't interrupts, the probe fails */
 202         if (irq == -1) {
 203                 device_printf(dev, "not an interrupt driven port, failed.\n");
 204                 return (ENXIO);
 205         }
 206
 207         /* reserve the interrupt resource, expecting irq is available to continue */
 208         lp->res_irq = bus_alloc_resource(dev, SYS_RES_IRQ, &zero, irq, irq, 1,
 209                                          RF_SHAREABLE);
 210         if (lp->res_irq == 0) {
 211                 device_printf(dev, "cannot reserve interrupt, failed.\n");
 212                 return (ENXIO);
 213         }
 214
 215         /*
 216          * lp dependent initialisation.
 217          */
 218         lp->lp_unit = device_get_unit(dev);
 219
 220         device_set_desc(dev, "PLIP network interface");
 221
 222         return (0);
 223 }
 224
 225 static int
 226 lp_attach (device_t dev)
 227 {
 228         struct lp_data *lp = DEVTOSOFTC(dev);
 229         struct ifnet *ifp = &lp->sc_if;
 230
 231         ifp->if_softc = lp;
 232         if_initname(ifp, "lp", device_get_unit(dev));
 233         ifp->if_mtu = LPMTU;
 234         ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
 235         ifp->if_ioctl = lpioctl;
 236         ifp->if_output = lpoutput;
 237         ifp->if_type = IFT_PARA;
 238         ifp->if_hdrlen = 0;
 239         ifp->if_addrlen = 0;
 240         ifq_set_maxlen(&ifp->if_snd, IFQ_MAXLEN);
 241         if_attach(ifp, NULL);
 242
 243         bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
 244
 245         return (0);
 246 }
 247 /*
 248  * Build the translation tables for the LPIP (BSD unix) protocol.
 249  * We don't want to calculate these nasties in our tight loop, so we
 250  * precalculate them when we initialize.
 251  */
 252 static int
 253 lpinittables (void)
 254 {
 255     int i;
 256
 257     if (!txmith)
 258         txmith = kmalloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
 259
 260     if (!ctxmith)
 261         ctxmith = kmalloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
 262
 263     for (i=0; i < LPIPTBLSIZE; i++) {
 264         ctxmith[i] = (i & 0xF0) >> 4;
 265         ctxmitl[i] = 0x10 | (i & 0x0F);
 266         ctrecvh[i] = (i & 0x78) << 1;
 267         ctrecvl[i] = (i & 0x78) >> 3;
 268     }
 269
 270     for (i=0; i < LPIPTBLSIZE; i++) {
 271         txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
 272         txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
 273         trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
 274         trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
 275     }
 276
 277     return 0;
 278 }
 279
 280 /*
 281  * Process an ioctl request.
 282  */
 283
 284 static int
 285 lpioctl (struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
 286 {
 287     device_t dev = UNITODEVICE(ifp->if_dunit);
 288     device_t ppbus = device_get_parent(dev);
 289     struct lp_data *sc = DEVTOSOFTC(dev);
 290     struct ifaddr *ifa = (struct ifaddr *)data;
 291     struct ifreq *ifr = (struct ifreq *)data;
 292     u_char *ptr;
 293     void *ih;
 294     int error;
 295
 296     switch (cmd) {
 297
 298     case SIOCSIFDSTADDR:
 299     case SIOCAIFADDR:
 300     case SIOCSIFADDR:
 301         if (ifa->ifa_addr->sa_family != AF_INET)
 302             return EAFNOSUPPORT;
 303
 304         ifp->if_flags |= IFF_UP;
 305         /* FALLTHROUGH */
 306     case SIOCSIFFLAGS:
 307         if ((!(ifp->if_flags & IFF_UP)) && (ifp->if_flags & IFF_RUNNING)) {
 308
 309             ppb_wctr(ppbus, 0x00);
 310             ifp->if_flags &= ~IFF_RUNNING;
 311
 312             /* IFF_UP is not set, try to release the bus anyway */
 313             ppb_release_bus(ppbus, dev);
 314             break;
 315         }
 316         if (((ifp->if_flags & IFF_UP)) && (!(ifp->if_flags & IFF_RUNNING))) {
 317
 318             /* XXX
 319              * Should the request be interruptible?
 320              */
 321             if ((error = ppb_request_bus(ppbus, dev, PPB_WAIT|PPB_INTR)))
 322                 return (error);
 323
 324             /* Now IFF_UP means that we own the bus */
 325
 326             ppb_set_mode(ppbus, PPB_COMPATIBLE);
 327
 328             if (lpinittables()) {
 329                 ppb_release_bus(ppbus, dev);
 330                 return ENOBUFS;
 331             }
 332
 333             sc->sc_ifbuf = kmalloc(sc->sc_if.if_mtu + MLPIPHDRLEN,
 334                                   M_DEVBUF, M_WAITOK);
 335             if (!sc->sc_ifbuf) {
 336                 ppb_release_bus(ppbus, dev);
 337                 return ENOBUFS;
 338             }
 339
 340             /* attach our interrupt handler, later detached when the bus is released */
 341             error = BUS_SETUP_INTR(ppbus, dev, sc->res_irq, 0,
 342                                    lp_intr, dev, &ih, NULL);
 343             if (error) {
 344                 ppb_release_bus(ppbus, dev);
 345                 return (error);
 346             }
 347
 348             ppb_wctr(ppbus, IRQENABLE);
 349             ifp->if_flags |= IFF_RUNNING;
 350         }
 351         break;
 352
 353     case SIOCSIFMTU:
 354         ptr = sc->sc_ifbuf;
 355         sc->sc_ifbuf = kmalloc(ifr->ifr_mtu+MLPIPHDRLEN, M_DEVBUF, M_WAITOK);
 356         if (ptr)
 357             kfree(ptr,M_DEVBUF);
 358         sc->sc_if.if_mtu = ifr->ifr_mtu;
 359         break;
 360
 361     case SIOCGIFMTU:
 362         ifr->ifr_mtu = sc->sc_if.if_mtu;
 363         break;
 364
 365     case SIOCADDMULTI:
 366     case SIOCDELMULTI:
 367         if (ifr == 0) {
 368             return EAFNOSUPPORT;                /* XXX */
 369         }
 370         switch (ifr->ifr_addr.sa_family) {
 371
 372         case AF_INET:
 373             break;
 374
 375         default:
 376             return EAFNOSUPPORT;
 377         }
 378         break;
 379
 380     case SIOCGIFMEDIA:
 381         /*
 382          * No ifmedia support at this stage; maybe use it
 383          * in future for eg. protocol selection.
 384          */
 385         return EINVAL;
 386
 387     default:
 388         lprintf("LP:ioctl(0x%lx)\n", cmd);
 389         return EINVAL;
 390     }
 391     return 0;
 392 }
 393
 394 static __inline int
 395 clpoutbyte (u_char byte, int spin, device_t ppbus)
 396 {
 397         ppb_wdtr(ppbus, ctxmitl[byte]);
 398         while (ppb_rstr(ppbus) & CLPIP_SHAKE)
 399                 if (--spin == 0) {
 400                         return 1;
 401                 }
 402         ppb_wdtr(ppbus, ctxmith[byte]);
 403         while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
 404                 if (--spin == 0) {
 405                         return 1;
 406                 }
 407         return 0;
 408 }
 409
 410 static __inline int
 411 clpinbyte (int spin, device_t ppbus)
 412 {
 413         u_char c, cl;
 414
 415         while((ppb_rstr(ppbus) & CLPIP_SHAKE))
 416             if(!--spin) {
 417                 return -1;
 418             }
 419         cl = ppb_rstr(ppbus);
 420         ppb_wdtr(ppbus, 0x10);
 421
 422         while(!(ppb_rstr(ppbus) & CLPIP_SHAKE))
 423             if(!--spin) {
 424                 return -1;
 425             }
 426         c = ppb_rstr(ppbus);
 427         ppb_wdtr(ppbus, 0x00);
 428
 429         return (ctrecvl[cl] | ctrecvh[c]);
 430 }
 431
 432 static void
 433 lptap(struct ifnet *ifp, struct mbuf *m)
 434 {
 435         /*
 436          * We need to prepend the address family as a four byte field.
 437          */
 438         static const uint32_t af = AF_INET;
 439
 440         if (ifp->if_bpf)
 441                 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af));
 442 }
 443
 444 static void
 445 lp_intr (void *arg)
 446 {
 447         device_t dev = (device_t)arg;
 448         device_t ppbus = device_get_parent(dev);
 449         struct lp_data *sc = DEVTOSOFTC(dev);
 450         int len, j;
 451         u_char *bp;
 452         u_char c, cl;
 453         struct mbuf *top;
 454
 455         crit_enter();
 456
 457         if (sc->sc_if.if_flags & IFF_LINK0) {
 458
 459             /* Ack. the request */
 460             ppb_wdtr(ppbus, 0x01);
 461
 462             /* Get the packet length */
 463             j = clpinbyte(LPMAXSPIN2, ppbus);
 464             if (j == -1)
 465                 goto err;
 466             len = j;
 467             j = clpinbyte(LPMAXSPIN2, ppbus);
 468             if (j == -1)
 469                 goto err;
 470             len = len + (j << 8);
 471             if (len > sc->sc_if.if_mtu + MLPIPHDRLEN)
 472                 goto err;
 473
 474             bp  = sc->sc_ifbuf;
 475
 476             while (len--) {
 477                 j = clpinbyte(LPMAXSPIN2, ppbus);
 478                 if (j == -1) {
 479                     goto err;
 480                 }
 481                 *bp++ = j;
 482             }
 483             /* Get and ignore checksum */
 484             j = clpinbyte(LPMAXSPIN2, ppbus);
 485             if (j == -1) {
 486                 goto err;
 487             }
 488
 489             len = bp - sc->sc_ifbuf;
 490             if (len <= CLPIPHDRLEN)
 491                 goto err;
 492
 493             sc->sc_iferrs = 0;
 494
 495             len -= CLPIPHDRLEN;
 496             sc->sc_if.if_ipackets++;
 497             sc->sc_if.if_ibytes += len;
 498             top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, &sc->sc_if, 0);
 499             if (top) {
 500                 if (sc->sc_if.if_bpf)
 501                     lptap(&sc->sc_if, top);
 502                 netisr_queue(NETISR_IP, top);
 503             }
 504             goto done;
 505         }
 506         while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
 507             len = sc->sc_if.if_mtu + LPIPHDRLEN;
 508             bp  = sc->sc_ifbuf;
 509             while (len--) {
 510
 511                 cl = ppb_rstr(ppbus);
 512                 ppb_wdtr(ppbus, 8);
 513
 514                 j = LPMAXSPIN2;
 515                 while((ppb_rstr(ppbus) & LPIP_SHAKE))
 516                     if(!--j) goto err;
 517
 518                 c = ppb_rstr(ppbus);
 519                 ppb_wdtr(ppbus, 0);
 520
 521                 *bp++= trecvh[cl] | trecvl[c];
 522
 523                 j = LPMAXSPIN2;
 524                 while (!((cl=ppb_rstr(ppbus)) & LPIP_SHAKE)) {
 525                     if (cl != c &&
 526                         (((cl = ppb_rstr(ppbus)) ^ 0xb8) & 0xf8) ==
 527                           (c & 0xf8))
 528                         goto end;
 529                     if (!--j) goto err;
 530                 }
 531             }
 532
 533         end:
 534             len = bp - sc->sc_ifbuf;
 535             if (len <= LPIPHDRLEN)
 536                 goto err;
 537
 538             sc->sc_iferrs = 0;
 539
 540             len -= LPIPHDRLEN;
 541             sc->sc_if.if_ipackets++;
 542             sc->sc_if.if_ibytes += len;
 543             top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, &sc->sc_if, 0);
 544             if (top) {
 545                 if (sc->sc_if.if_bpf)
 546                     lptap(&sc->sc_if, top);
 547                 netisr_queue(NETISR_IP, top);
 548             }
 549         }
 550         goto done;
 551
 552     err:
 553         ppb_wdtr(ppbus, 0);
 554         lprintf("R");
 555         sc->sc_if.if_ierrors++;
 556         sc->sc_iferrs++;
 557
 558         /*
 559          * We are not able to send receive anything for now,
 560          * so stop wasting our time
 561          */
 562         if (sc->sc_iferrs > LPMAXERRS) {
 563             kprintf("lp%d: Too many errors, Going off-line.\n", device_get_unit(dev));
 564             ppb_wctr(ppbus, 0x00);
 565             sc->sc_if.if_flags &= ~IFF_RUNNING;
 566             sc->sc_iferrs=0;
 567         }
 568
 569     done:
 570         crit_exit();
 571         return;
 572 }
 573
 574 static __inline int
 575 lpoutbyte (u_char byte, int spin, device_t ppbus)
 576 {
 577     ppb_wdtr(ppbus, txmith[byte]);
 578     while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
 579         if (--spin == 0)
 580                 return 1;
 581     ppb_wdtr(ppbus, txmitl[byte]);
 582     while (ppb_rstr(ppbus) & LPIP_SHAKE)
 583         if (--spin == 0)
 584                 return 1;
 585     return 0;
 586 }
 587
 588 static int
 589 lpoutput (struct ifnet *ifp, struct mbuf *m,
 590           struct sockaddr *dst, struct rtentry *rt)
 591 {
 592     device_t dev = UNITODEVICE(ifp->if_dunit);
 593     device_t ppbus = device_get_parent(dev);
 594     int err;
 595     struct mbuf *mm;
 596     u_char *cp = "\0\0";
 597     u_char chksum = 0;
 598     int count = 0;
 599     int i, len, spin;
 600
 601     /* We need a sensible value if we abort */
 602     cp++;
 603     ifp->if_flags |= IFF_RUNNING;
 604
 605     err = 1;                    /* assume we're aborting because of an error */
 606
 607     crit_enter();
 608
 609     /* Suspend (on laptops) or receive-errors might have taken us offline */
 610     ppb_wctr(ppbus, IRQENABLE);
 611
 612     if (ifp->if_flags & IFF_LINK0) {
 613
 614         if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
 615             lprintf("&");
 616             lp_intr(dev);
 617         }
 618
 619         /* Alert other end to pending packet */
 620         spin = LPMAXSPIN1;
 621         ppb_wdtr(ppbus, 0x08);
 622         while ((ppb_rstr(ppbus) & 0x08) == 0)
 623                 if (--spin == 0) {
 624                         goto nend;
 625                 }
 626
 627         /* Calculate length of packet, then send that */
 628
 629         count += 14;            /* Ethernet header len */
 630
 631         mm = m;
 632         for (mm = m; mm; mm = mm->m_next) {
 633                 count += mm->m_len;
 634         }
 635         if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
 636                 goto nend;
 637         if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
 638                 goto nend;
 639
 640         /* Send dummy ethernet header */
 641         for (i = 0; i < 12; i++) {
 642                 if (clpoutbyte(i, LPMAXSPIN1, ppbus))
 643                         goto nend;
 644                 chksum += i;
 645         }
 646
 647         if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
 648                 goto nend;
 649         if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
 650                 goto nend;
 651         chksum += 0x08 + 0x00;          /* Add into checksum */
 652
 653         mm = m;
 654         do {
 655                 cp = mtod(mm, u_char *);
 656                 len = mm->m_len;
 657                 while (len--) {
 658                         chksum += *cp;
 659                         if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
 660                                 goto nend;
 661                 }
 662         } while ((mm = mm->m_next));
 663
 664         /* Send checksum */
 665         if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
 666                 goto nend;
 667
 668         /* Go quiescent */
 669         ppb_wdtr(ppbus, 0);
 670
 671         err = 0;                        /* No errors */
 672
 673         nend:
 674         if (err)  {                             /* if we didn't timeout... */
 675                 ifp->if_oerrors++;
 676                 lprintf("X");
 677         } else {
 678                 ifp->if_opackets++;
 679                 ifp->if_obytes += m->m_pkthdr.len;
 680                 if (ifp->if_bpf)
 681                     lptap(ifp, m);
 682         }
 683
 684         m_freem(m);
 685
 686         if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
 687                 lprintf("^");
 688                 lp_intr(dev);
 689         }
 690         crit_exit();
 691         return 0;
 692     }
 693
 694     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
 695         lprintf("&");
 696         lp_intr(dev);
 697     }
 698
 699     if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
 700         goto end;
 701     if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
 702         goto end;
 703
 704     mm = m;
 705     do {
 706         cp = mtod(mm,u_char *);
 707         len = mm->m_len;
 708         while (len--)
 709             if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
 710                 goto end;
 711     } while ((mm = mm->m_next));
 712
 713     err = 0;                            /* no errors were encountered */
 714
 715     end:
 716     --cp;
 717     ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
 718
 719     if (err)  {                         /* if we didn't timeout... */
 720         ifp->if_oerrors++;
 721         lprintf("X");
 722     } else {
 723         ifp->if_opackets++;
 724         ifp->if_obytes += m->m_pkthdr.len;
 725         if (ifp->if_bpf)
 726             lptap(ifp, m);
 727     }
 728
 729     m_freem(m);
 730
 731     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
 732         lprintf("^");
 733         lp_intr(dev);
 734     }
 735
 736     crit_exit();
 737     return 0;
 738 }
 739
 740 /*
 741  * Because plip is a static device that always exists under any attached
 742  * ppbus device, and not scanned by the ppbus device, we need an identify
 743  * function to install the device.
 744  */
 745 static device_method_t lp_methods[] = {
 746         /* device interface */
 747         DEVMETHOD(device_identify,      bus_generic_identify),
 748         DEVMETHOD(device_probe,         lp_probe),
 749         DEVMETHOD(device_attach,        lp_attach),
 750
 751         { 0, 0 }
 752 };
 753
 754 static driver_t lp_driver = {
 755   "plip",
 756   lp_methods,
 757   sizeof(struct lp_data),
 758 };
 759
 760 DECLARE_DUMMY_MODULE(if_plip);
 761 DRIVER_MODULE(if_plip, ppbus, lp_driver, lp_devclass, 0, 0);
 762