if_plip.c revision 50477 
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: head/sys/dev/ppbus/if_plip.c 50477 1999-08-28 01:08:13Z peter $
28 */
29
30/*
31 * Parallel port TCP/IP interfaces added.  I looked at the driver from
32 * MACH but this is a complete rewrite, and btw. incompatible, and it
33 * should perform better too.  I have never run the MACH driver though.
34 *
35 * This driver sends two bytes (0x08, 0x00) in front of each packet,
36 * to allow us to distinguish another format later.
37 *
38 * Now added an Linux/Crynwr compatibility mode which is enabled using
39 * IF_LINK0 - Tim Wilkinson.
40 *
41 * TODO:
42 *    Make HDLC/PPP mode, use IF_LLC1 to enable.
43 *
44 * Connect the two computers using a Laplink parallel cable to use this
45 * feature:
46 *
47 *      +----------------------------------------+
48 * 	|A-name	A-End	B-End	Descr.	Port/Bit |
49 *      +----------------------------------------+
50 *	|DATA0	2	15	Data	0/0x01   |
51 *	|-ERROR	15	2	   	1/0x08   |
52 *      +----------------------------------------+
53 *	|DATA1	3	13	Data	0/0x02	 |
54 *	|+SLCT	13	3	   	1/0x10   |
55 *      +----------------------------------------+
56 *	|DATA2	4	12	Data	0/0x04   |
57 *	|+PE	12	4	   	1/0x20   |
58 *      +----------------------------------------+
59 *	|DATA3	5	10	Strobe	0/0x08   |
60 *	|-ACK	10	5	   	1/0x40   |
61 *      +----------------------------------------+
62 *	|DATA4	6	11	Data	0/0x10   |
63 *	|BUSY	11	6	   	1/~0x80  |
64 *      +----------------------------------------+
65 *	|GND	18-25	18-25	GND	-        |
66 *      +----------------------------------------+
67 *
68 * Expect transfer-rates up to 75 kbyte/sec.
69 *
70 * If GCC could correctly grok
71 *	register int port asm("edx")
72 * the code would be cleaner
73 *
74 * Poul-Henning Kamp <phk@freebsd.org>
75 */
76
77/*
78 * Update for ppbus, PLIP support only - Nicolas Souchu
79 */
80
81#include <sys/param.h>
82#include <sys/systm.h>
83#include <sys/mbuf.h>
84#include <sys/socket.h>
85#include <sys/sockio.h>
86#include <sys/kernel.h>
87#include <sys/malloc.h>
88
89#include <net/if.h>
90#include <net/if_types.h>
91#include <net/netisr.h>
92
93#include <netinet/in.h>
94#include <netinet/in_var.h>
95
96#include "bpf.h"
97#if NBPF > 0
98#include <net/bpf.h>
99#endif
100
101#include <dev/ppbus/ppbconf.h>
102
103#include "opt_plip.h"
104
105#ifndef LPMTU			/* MTU for the lp# interfaces */
106#define	LPMTU	1500
107#endif
108
109#ifndef LPMAXSPIN1		/* DELAY factor for the lp# interfaces */
110#define	LPMAXSPIN1	8000   /* Spinning for remote intr to happen */
111#endif
112
113#ifndef LPMAXSPIN2		/* DELAY factor for the lp# interfaces */
114#define	LPMAXSPIN2	500	/* Spinning for remote handshake to happen */
115#endif
116
117#ifndef LPMAXERRS		/* Max errors before !RUNNING */
118#define	LPMAXERRS	100
119#endif
120
121#define CLPIPHDRLEN	14	/* We send dummy ethernet addresses (two) + packet type in front of packet */
122#define	CLPIP_SHAKE	0x80	/* This bit toggles between nibble reception */
123#define MLPIPHDRLEN	CLPIPHDRLEN
124
125#define LPIPHDRLEN	2	/* We send 0x08, 0x00 in front of packet */
126#define	LPIP_SHAKE	0x40	/* This bit toggles between nibble reception */
127#if !defined(MLPIPHDRLEN) || LPIPHDRLEN > MLPIPHDRLEN
128#define MLPIPHDRLEN	LPIPHDRLEN
129#endif
130
131#define	LPIPTBLSIZE	256	/* Size of octet translation table */
132
133#define lprintf		if (lptflag) printf
134
135#ifdef PLIP_DEBUG
136static int volatile lptflag = 1;
137#else
138static int volatile lptflag = 0;
139#endif
140
141struct lpt_softc {
142	unsigned short lp_unit;
143
144	struct ppb_device lp_dev;
145
146	struct  ifnet	sc_if;
147	u_char		*sc_ifbuf;
148	int		sc_iferrs;
149};
150
151static int	nlp = 0;
152#define MAXPLIP	8			/* XXX not much better! */
153static struct lpt_softc *lpdata[MAXPLIP];
154
155
156/* Tables for the lp# interface */
157static u_char *txmith;
158#define txmitl (txmith+(1*LPIPTBLSIZE))
159#define trecvh (txmith+(2*LPIPTBLSIZE))
160#define trecvl (txmith+(3*LPIPTBLSIZE))
161
162static u_char *ctxmith;
163#define ctxmitl (ctxmith+(1*LPIPTBLSIZE))
164#define ctrecvh (ctxmith+(2*LPIPTBLSIZE))
165#define ctrecvl (ctxmith+(3*LPIPTBLSIZE))
166
167/* Functions for the lp# interface */
168static struct ppb_device	*lpprobe(struct ppb_data *);
169static int			lpattach(struct ppb_device *);
170
171static int lpinittables(void);
172static int lpioctl(struct ifnet *, u_long, caddr_t);
173static int lpoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
174	struct rtentry *);
175static void lpintr(int);
176
177/*
178 * Make ourselves visible as a ppbus driver
179 */
180
181static struct ppb_driver lpdriver = {
182    lpprobe, lpattach, "lp"
183};
184DATA_SET(ppbdriver_set, lpdriver);
185
186
187/*
188 * lpprobe()
189 */
190static struct ppb_device *
191lpprobe(struct ppb_data *ppb)
192{
193	struct lpt_softc *lp;
194
195	/* if we haven't interrupts, the probe fails */
196	if (!ppb->ppb_link->id_irq) {
197		printf("plip: not an interrupt driven port, failed.\n");
198		return (0);
199	}
200
201	lp = (struct lpt_softc *) malloc(sizeof(struct lpt_softc),
202							M_TEMP, M_NOWAIT);
203	if (!lp) {
204		printf("lp: cannot malloc!\n");
205		return (0);
206	}
207	bzero(lp, sizeof(struct lpt_softc));
208
209	lpdata[nlp] = lp;
210
211	/*
212	 * lp dependent initialisation.
213	 */
214	lp->lp_unit = nlp;
215
216	if (bootverbose)
217		printf("plip: irq %d\n", ppb->ppb_link->id_irq);
218
219	/*
220	 * ppbus dependent initialisation.
221	 */
222	lp->lp_dev.id_unit = lp->lp_unit;
223	lp->lp_dev.name = lpdriver.name;
224	lp->lp_dev.ppb = ppb;
225	lp->lp_dev.intr = lpintr;
226
227	/* Ok, go to next device on next probe */
228	nlp ++;
229
230	return (&lp->lp_dev);
231}
232
233static int
234lpattach (struct ppb_device *dev)
235{
236	int unit = dev->id_unit;
237	struct lpt_softc *sc = lpdata[unit];
238	struct ifnet *ifp = &sc->sc_if;
239
240	/*
241	 * Report ourselves
242	 */
243	printf("plip%d: <PLIP network interface> on ppbus %d\n",
244	       dev->id_unit, dev->ppb->ppb_link->adapter_unit);
245
246	ifp->if_softc = sc;
247	ifp->if_name = "lp";
248	ifp->if_unit = unit;
249	ifp->if_mtu = LPMTU;
250	ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
251	ifp->if_ioctl = lpioctl;
252	ifp->if_output = lpoutput;
253	ifp->if_type = IFT_PARA;
254	ifp->if_hdrlen = 0;
255	ifp->if_addrlen = 0;
256	ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
257	if_attach(ifp);
258
259#if NBPF > 0
260	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
261#endif
262
263	return (1);
264}
265/*
266 * Build the translation tables for the LPIP (BSD unix) protocol.
267 * We don't want to calculate these nasties in our tight loop, so we
268 * precalculate them when we initialize.
269 */
270static int
271lpinittables (void)
272{
273    int i;
274
275    if (!txmith)
276	txmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
277
278    if (!txmith)
279	return 1;
280
281    if (!ctxmith)
282	ctxmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
283
284    if (!ctxmith)
285	return 1;
286
287    for (i=0; i < LPIPTBLSIZE; i++) {
288	ctxmith[i] = (i & 0xF0) >> 4;
289	ctxmitl[i] = 0x10 | (i & 0x0F);
290	ctrecvh[i] = (i & 0x78) << 1;
291	ctrecvl[i] = (i & 0x78) >> 3;
292    }
293
294    for (i=0; i < LPIPTBLSIZE; i++) {
295	txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
296	txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
297	trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
298	trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
299    }
300
301    return 0;
302}
303
304/*
305 * Process an ioctl request.
306 */
307
308static int
309lpioctl (struct ifnet *ifp, u_long cmd, caddr_t data)
310{
311    struct lpt_softc *sc = lpdata[ifp->if_unit];
312    struct ifaddr *ifa = (struct ifaddr *)data;
313    struct ifreq *ifr = (struct ifreq *)data;
314    u_char *ptr;
315    int error;
316
317    switch (cmd) {
318
319    case SIOCSIFDSTADDR:
320    case SIOCAIFADDR:
321    case SIOCSIFADDR:
322	if (ifa->ifa_addr->sa_family != AF_INET)
323	    return EAFNOSUPPORT;
324
325	ifp->if_flags |= IFF_UP;
326	/* FALLTHROUGH */
327    case SIOCSIFFLAGS:
328	if ((!(ifp->if_flags & IFF_UP)) && (ifp->if_flags & IFF_RUNNING)) {
329
330	    ppb_wctr(&sc->lp_dev, 0x00);
331	    ifp->if_flags &= ~IFF_RUNNING;
332
333	    /* IFF_UP is not set, try to release the bus anyway */
334	    ppb_release_bus(&sc->lp_dev);
335	    break;
336	}
337	if (((ifp->if_flags & IFF_UP)) && (!(ifp->if_flags & IFF_RUNNING))) {
338
339	    /* XXX
340	     * Should the request be interruptible?
341	     */
342	    if ((error = ppb_request_bus(&sc->lp_dev, PPB_WAIT|PPB_INTR)))
343		return (error);
344
345	    /* Now IFF_UP means that we own the bus */
346
347	    ppb_set_mode(&sc->lp_dev, PPB_COMPATIBLE);
348
349	    if (lpinittables()) {
350		ppb_release_bus(&sc->lp_dev);
351		return ENOBUFS;
352	    }
353
354	    sc->sc_ifbuf = malloc(sc->sc_if.if_mtu + MLPIPHDRLEN,
355				  M_DEVBUF, M_WAITOK);
356	    if (!sc->sc_ifbuf) {
357		ppb_release_bus(&sc->lp_dev);
358		return ENOBUFS;
359	    }
360
361	    ppb_wctr(&sc->lp_dev, IRQENABLE);
362	    ifp->if_flags |= IFF_RUNNING;
363	}
364	break;
365
366    case SIOCSIFMTU:
367	ptr = sc->sc_ifbuf;
368	sc->sc_ifbuf = malloc(ifr->ifr_mtu+MLPIPHDRLEN, M_DEVBUF, M_NOWAIT);
369	if (!sc->sc_ifbuf) {
370	    sc->sc_ifbuf = ptr;
371	    return ENOBUFS;
372	}
373	if (ptr)
374	    free(ptr,M_DEVBUF);
375	sc->sc_if.if_mtu = ifr->ifr_mtu;
376	break;
377
378    case SIOCGIFMTU:
379	ifr->ifr_mtu = sc->sc_if.if_mtu;
380	break;
381
382    case SIOCADDMULTI:
383    case SIOCDELMULTI:
384	if (ifr == 0) {
385	    return EAFNOSUPPORT;		/* XXX */
386	}
387	switch (ifr->ifr_addr.sa_family) {
388
389	case AF_INET:
390	    break;
391
392	default:
393	    return EAFNOSUPPORT;
394	}
395	break;
396
397    case SIOCGIFMEDIA:
398	/*
399	 * No ifmedia support at this stage; maybe use it
400	 * in future for eg. protocol selection.
401	 */
402	return EINVAL;
403
404    default:
405	lprintf("LP:ioctl(0x%lx)\n", cmd);
406	return EINVAL;
407    }
408    return 0;
409}
410
411static __inline int
412clpoutbyte (u_char byte, int spin, struct ppb_device *dev)
413{
414	ppb_wdtr(dev, ctxmitl[byte]);
415	while (ppb_rstr(dev) & CLPIP_SHAKE)
416		if (--spin == 0) {
417			return 1;
418		}
419	ppb_wdtr(dev, ctxmith[byte]);
420	while (!(ppb_rstr(dev) & CLPIP_SHAKE))
421		if (--spin == 0) {
422			return 1;
423		}
424	return 0;
425}
426
427static __inline int
428clpinbyte (int spin, struct ppb_device *dev)
429{
430	u_char c, cl;
431
432	while((ppb_rstr(dev) & CLPIP_SHAKE))
433	    if(!--spin) {
434		return -1;
435	    }
436	cl = ppb_rstr(dev);
437	ppb_wdtr(dev, 0x10);
438
439	while(!(ppb_rstr(dev) & CLPIP_SHAKE))
440	    if(!--spin) {
441		return -1;
442	    }
443	c = ppb_rstr(dev);
444	ppb_wdtr(dev, 0x00);
445
446	return (ctrecvl[cl] | ctrecvh[c]);
447}
448
449#if NBPF > 0
450static void
451lptap(struct ifnet *ifp, struct mbuf *m)
452{
453	/*
454	 * Send a packet through bpf. We need to prepend the address family
455	 * as a four byte field. Cons up a dummy header to pacify bpf. This
456	 * is safe because bpf will only read from the mbuf (i.e., it won't
457	 * try to free it or keep a pointer to it).
458	 */
459	u_int32_t af = AF_INET;
460	struct mbuf m0;
461
462	m0.m_next = m;
463	m0.m_len = sizeof(u_int32_t);
464	m0.m_data = (char *)&af;
465	bpf_mtap(ifp, &m0);
466}
467#endif
468
469static void
470lpintr (int unit)
471{
472	struct   lpt_softc *sc = lpdata[unit];
473	int len, s, j;
474	u_char *bp;
475	u_char c, cl;
476	struct mbuf *top;
477
478	s = splhigh();
479
480	if (sc->sc_if.if_flags & IFF_LINK0) {
481
482	    /* Ack. the request */
483	    ppb_wdtr(&sc->lp_dev, 0x01);
484
485	    /* Get the packet length */
486	    j = clpinbyte(LPMAXSPIN2, &sc->lp_dev);
487	    if (j == -1)
488		goto err;
489	    len = j;
490	    j = clpinbyte(LPMAXSPIN2, &sc->lp_dev);
491	    if (j == -1)
492		goto err;
493	    len = len + (j << 8);
494	    if (len > sc->sc_if.if_mtu + MLPIPHDRLEN)
495		goto err;
496
497	    bp  = sc->sc_ifbuf;
498
499	    while (len--) {
500	        j = clpinbyte(LPMAXSPIN2, &sc->lp_dev);
501	        if (j == -1) {
502		    goto err;
503	        }
504	        *bp++ = j;
505	    }
506	    /* Get and ignore checksum */
507	    j = clpinbyte(LPMAXSPIN2, &sc->lp_dev);
508	    if (j == -1) {
509	        goto err;
510	    }
511
512	    len = bp - sc->sc_ifbuf;
513	    if (len <= CLPIPHDRLEN)
514	        goto err;
515
516	    sc->sc_iferrs = 0;
517
518	    if (IF_QFULL(&ipintrq)) {
519	        lprintf("DROP");
520	        IF_DROP(&ipintrq);
521		goto done;
522	    }
523	    len -= CLPIPHDRLEN;
524	    sc->sc_if.if_ipackets++;
525	    sc->sc_if.if_ibytes += len;
526	    top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, &sc->sc_if, 0);
527	    if (top) {
528#if NBPF > 0
529		if (sc->sc_if.if_bpf)
530		    lptap(&sc->sc_if, top);
531#endif
532	        IF_ENQUEUE(&ipintrq, top);
533	        schednetisr(NETISR_IP);
534	    }
535	    goto done;
536	}
537	while ((ppb_rstr(&sc->lp_dev) & LPIP_SHAKE)) {
538	    len = sc->sc_if.if_mtu + LPIPHDRLEN;
539	    bp  = sc->sc_ifbuf;
540	    while (len--) {
541
542		cl = ppb_rstr(&sc->lp_dev);
543		ppb_wdtr(&sc->lp_dev, 8);
544
545		j = LPMAXSPIN2;
546		while((ppb_rstr(&sc->lp_dev) & LPIP_SHAKE))
547		    if(!--j) goto err;
548
549		c = ppb_rstr(&sc->lp_dev);
550		ppb_wdtr(&sc->lp_dev, 0);
551
552		*bp++= trecvh[cl] | trecvl[c];
553
554		j = LPMAXSPIN2;
555		while (!((cl=ppb_rstr(&sc->lp_dev)) & LPIP_SHAKE)) {
556		    if (cl != c &&
557			(((cl = ppb_rstr(&sc->lp_dev)) ^ 0xb8) & 0xf8) ==
558			  (c & 0xf8))
559			goto end;
560		    if (!--j) goto err;
561		}
562	    }
563
564	end:
565	    len = bp - sc->sc_ifbuf;
566	    if (len <= LPIPHDRLEN)
567		goto err;
568
569	    sc->sc_iferrs = 0;
570
571	    if (IF_QFULL(&ipintrq)) {
572		lprintf("DROP");
573		IF_DROP(&ipintrq);
574		goto done;
575	    }
576	    len -= LPIPHDRLEN;
577	    sc->sc_if.if_ipackets++;
578	    sc->sc_if.if_ibytes += len;
579	    top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, &sc->sc_if, 0);
580	    if (top) {
581#if NBPF > 0
582		if (sc->sc_if.if_bpf)
583		    lptap(&sc->sc_if, top);
584#endif
585		IF_ENQUEUE(&ipintrq, top);
586		schednetisr(NETISR_IP);
587	    }
588	}
589	goto done;
590
591    err:
592	ppb_wdtr(&sc->lp_dev, 0);
593	lprintf("R");
594	sc->sc_if.if_ierrors++;
595	sc->sc_iferrs++;
596
597	/*
598	 * We are not able to send receive anything for now,
599	 * so stop wasting our time
600	 */
601	if (sc->sc_iferrs > LPMAXERRS) {
602	    printf("lp%d: Too many errors, Going off-line.\n", unit);
603	    ppb_wctr(&sc->lp_dev, 0x00);
604	    sc->sc_if.if_flags &= ~IFF_RUNNING;
605	    sc->sc_iferrs=0;
606	}
607
608    done:
609	splx(s);
610	return;
611}
612
613static __inline int
614lpoutbyte (u_char byte, int spin, struct ppb_device *dev)
615{
616    ppb_wdtr(dev, txmith[byte]);
617    while (!(ppb_rstr(dev) & LPIP_SHAKE))
618	if (--spin == 0)
619		return 1;
620    ppb_wdtr(dev, txmitl[byte]);
621    while (ppb_rstr(dev) & LPIP_SHAKE)
622	if (--spin == 0)
623		return 1;
624    return 0;
625}
626
627static int
628lpoutput (struct ifnet *ifp, struct mbuf *m,
629	  struct sockaddr *dst, struct rtentry *rt)
630{
631    struct lpt_softc *sc = lpdata[ifp->if_unit];
632    int s, err;
633    struct mbuf *mm;
634    u_char *cp = "\0\0";
635    u_char chksum = 0;
636    int count = 0;
637    int i, len, spin;
638
639    /* We need a sensible value if we abort */
640    cp++;
641    ifp->if_flags |= IFF_RUNNING;
642
643    err = 1;			/* assume we're aborting because of an error */
644
645    s = splhigh();
646
647    /* Suspend (on laptops) or receive-errors might have taken us offline */
648    ppb_wctr(&sc->lp_dev, IRQENABLE);
649
650    if (ifp->if_flags & IFF_LINK0) {
651
652	if (!(ppb_rstr(&sc->lp_dev) & CLPIP_SHAKE)) {
653	    lprintf("&");
654	    lpintr(ifp->if_unit);
655	}
656
657	/* Alert other end to pending packet */
658	spin = LPMAXSPIN1;
659	ppb_wdtr(&sc->lp_dev, 0x08);
660	while ((ppb_rstr(&sc->lp_dev) & 0x08) == 0)
661		if (--spin == 0) {
662			goto nend;
663		}
664
665	/* Calculate length of packet, then send that */
666
667	count += 14;		/* Ethernet header len */
668
669	mm = m;
670	for (mm = m; mm; mm = mm->m_next) {
671		count += mm->m_len;
672	}
673	if (clpoutbyte(count & 0xFF, LPMAXSPIN1, &sc->lp_dev))
674		goto nend;
675	if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, &sc->lp_dev))
676		goto nend;
677
678	/* Send dummy ethernet header */
679	for (i = 0; i < 12; i++) {
680		if (clpoutbyte(i, LPMAXSPIN1, &sc->lp_dev))
681			goto nend;
682		chksum += i;
683	}
684
685	if (clpoutbyte(0x08, LPMAXSPIN1, &sc->lp_dev))
686		goto nend;
687	if (clpoutbyte(0x00, LPMAXSPIN1, &sc->lp_dev))
688		goto nend;
689	chksum += 0x08 + 0x00;		/* Add into checksum */
690
691	mm = m;
692	do {
693		cp = mtod(mm, u_char *);
694		len = mm->m_len;
695		while (len--) {
696			chksum += *cp;
697			if (clpoutbyte(*cp++, LPMAXSPIN2, &sc->lp_dev))
698				goto nend;
699		}
700	} while ((mm = mm->m_next));
701
702	/* Send checksum */
703	if (clpoutbyte(chksum, LPMAXSPIN2, &sc->lp_dev))
704		goto nend;
705
706	/* Go quiescent */
707	ppb_wdtr(&sc->lp_dev, 0);
708
709	err = 0;			/* No errors */
710
711	nend:
712	if (err)  {				/* if we didn't timeout... */
713		ifp->if_oerrors++;
714		lprintf("X");
715	} else {
716		ifp->if_opackets++;
717		ifp->if_obytes += m->m_pkthdr.len;
718#if NBPF > 0
719		if (ifp->if_bpf)
720		    lptap(ifp, m);
721#endif
722	}
723
724	m_freem(m);
725
726	if (!(ppb_rstr(&sc->lp_dev) & CLPIP_SHAKE)) {
727		lprintf("^");
728		lpintr(ifp->if_unit);
729	}
730	(void) splx(s);
731	return 0;
732    }
733
734    if (ppb_rstr(&sc->lp_dev) & LPIP_SHAKE) {
735        lprintf("&");
736        lpintr(ifp->if_unit);
737    }
738
739    if (lpoutbyte(0x08, LPMAXSPIN1, &sc->lp_dev))
740        goto end;
741    if (lpoutbyte(0x00, LPMAXSPIN2, &sc->lp_dev))
742        goto end;
743
744    mm = m;
745    do {
746        cp = mtod(mm,u_char *);
747	len = mm->m_len;
748        while (len--)
749	    if (lpoutbyte(*cp++, LPMAXSPIN2, &sc->lp_dev))
750	        goto end;
751    } while ((mm = mm->m_next));
752
753    err = 0;				/* no errors were encountered */
754
755    end:
756    --cp;
757    ppb_wdtr(&sc->lp_dev, txmitl[*cp] ^ 0x17);
758
759    if (err)  {				/* if we didn't timeout... */
760	ifp->if_oerrors++;
761        lprintf("X");
762    } else {
763	ifp->if_opackets++;
764	ifp->if_obytes += m->m_pkthdr.len;
765#if NBPF > 0
766	if (ifp->if_bpf)
767	    lptap(ifp, m);
768#endif
769    }
770
771    m_freem(m);
772
773    if (ppb_rstr(&sc->lp_dev) & LPIP_SHAKE) {
774	lprintf("^");
775	lpintr(ifp->if_unit);
776    }
777
778    (void) splx(s);
779    return 0;
780}
781