NetBSD/sys/arch/pc532/dev/lpt.c

/*	$NetBSD: lpt.c,v 1.30 1999/05/18 23:52:53 thorpej Exp $	*/

/*
 * Copyright (c) 1994 Matthias Pfaller.
 * Copyright (c) 1994 Poul-Henning Kamp
 * Copyright (c) 1993, 1994 Charles M. Hannum.
 * Copyright (c) 1990 William F. Jolitz, TeleMuse
 * 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 software is a component of "386BSD" developed by 
 *	William F. Jolitz, TeleMuse.
 * 4. Neither the name of the developer nor the name "386BSD"
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``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 DEVELOPER 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.
 */

/*
 * THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ 
 * AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS 
 * SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT. 
 * THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT 
 * NOT MAKE USE OF THIS WORK.
 *
 * FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED
 * BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN 
 * REFERENCES SUCH AS THE  "PORTING UNIX TO THE 386" SERIES 
 * (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING 
 * JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND 
 * LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE 
 * ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS 
 * OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992.
 */

/*
 * Device Driver for Matthias's parallel printer port.
 * This driver is based on the i386 lpt driver and
 * some IP code from Poul-Henning Kamp.
 */
#include "opt_inet.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/buf.h>
#include <sys/kernel.h>
#include <sys/ioctl.h>
#include <sys/uio.h>
#include <sys/device.h>
#include <sys/syslog.h>
#include <sys/malloc.h>

#include <machine/autoconf.h>
#include <machine/conf.h>

#if defined(INET) && defined(PLIP)
#include "bpfilter.h"
#include <sys/mbuf.h>
#include <sys/socket.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/if_ether.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/if_inarp.h>
#if NBPFILTER > 0
#include <sys/time.h>
#include <net/bpf.h>
#endif
#endif

#include "lpt.h"
#include "lptreg.h"

#define	LPT_INVERT	(LPC_NBUSY|LPC_NERROR|LPC_NACK|LPC_ONLINE)
#define	LPT_MASK	(LPC_NBUSY|LPC_NERROR|LPC_NACK|LPC_NOPAPER|LPC_ONLINE)

#define	TIMEOUT		hz*16	/* wait up to 16 seconds for a ready */
#define	STEP		hz/4

#define	LPTPRI		(PZERO+8)
#define	LPT_BSIZE	1024

#if defined(INET) && defined(PLIP)
#ifndef PLIPMTU			/* MTU for the plip# interfaces */
#if defined(COMPAT_PLIP10)
#define	PLIPMTU		1600				/* Linux 1.0.x */
#elif defined(COMPAT_PLIP11)
#define	PLIPMTU		(ETHERMTU - ifp->if_hdrlen)	/* Linux 1.1.x */
#else
#define PLIPMTU		ETHERMTU			/* Linux 1.3.x */
#endif
#endif

#ifndef PLIPMXSPIN1		/* DELAY factor for the plip# interfaces */
#define	PLIPMXSPIN1	50000	/* Spinning for remote intr to happen */
#endif

#ifndef PLIPMXSPIN2		/* DELAY factor for the plip# interfaces */
#define	PLIPMXSPIN2	50000	/* Spinning for remote handshake to happen */
#endif

#ifndef PLIPMXERRS		/* Max errors before !RUNNING */
#define	PLIPMXERRS	20
#endif
#ifndef PLIPMXRETRY
#define PLIPMXRETRY	20	/* Max number of retransmits */
#endif
#ifndef PLIPRETRY
#define PLIPRETRY	hz/50	/* Time between retransmits */
#endif
#endif

struct lpt_softc {
	struct device sc_dev;
	size_t sc_count;
	u_char *sc_inbuf;
	u_char *sc_cp;
	volatile struct i8255 *sc_i8255;
	int sc_irq;
	u_char sc_state;
#define	LPT_OPEN	0x01	/* device is open */
#define	LPT_INIT	0x02	/* waiting to initialize for open */

	u_char sc_status;
	u_char sc_flags;
#define	LPT_AUTOLF	0x20	/* automatic LF on CR */
#define	LPT_NOPRIME	0x40	/* don't prime on open */

#if defined(INET) && defined(PLIP)
	struct	ethercom sc_ethercom;
	u_char		*sc_ifbuf;
	int		sc_ifierrs;	/* consecutive input errors */
	int		sc_ifoerrs;	/* consecutive output errors */
	int		sc_ifsoftint;	/* i/o software interrupt */
	volatile int	sc_pending;	/* interrputs pending */
#define PLIP_IPENDING	1
#define PLIP_OPENDING	2

#if defined(COMPAT_PLIP10)
	u_char		sc_adrcksum;
#endif
#endif
};

#define	LPTUNIT(s)	(minor(s) & 0x1f)
#define	LPTFLAGS(s)	(minor(s) & 0xe0)
#define LPTSOFTC(n)	((struct lpt_softc *) lpt_cd.cd_devs[n])

static int lptmatch __P((struct device *, struct cfdata *, void *aux));
static void lptattach __P((struct device *, struct device *, void *));
static void lptintr __P((void *));
static int notready __P((u_char, struct lpt_softc *));
static void lptout __P((void *));
static int pushbytes __P((struct lpt_softc *));

#if defined(INET) && defined(PLIP)
/* Functions for the plip# interface */
static void	plipattach __P((struct lpt_softc *,int));
static void	plipinput __P((struct lpt_softc *));
static int	plipioctl __P((struct ifnet *, u_long, caddr_t));
static void	plipoutput __P((void *));
#ifndef __OPTIMIZE__
static
#endif
	int	plipreceive __P((volatile struct i8255 *, u_char *, int));
static void	pliprxenable __P((void *));
static void	plipsoftint __P((void *));
static void	plipstart __P((struct ifnet *));
#ifndef __OPTIMIZE__
static
#endif
	int	pliptransmit __P((volatile struct i8255 *, u_char *, int));
#endif

struct cfattach lpt_ca = {
	sizeof(struct lpt_softc), lptmatch, lptattach
};

extern struct cfdriver lpt_cd;

static int
lptmatch(parent, cf, aux)
	struct device *parent;
	struct cfdata *cf;
	void *aux;
{
	struct confargs *ca = aux;
	volatile struct i8255 *i8255 =
		(volatile struct i8255 *)((struct cfdata *)cf)->cf_addr;
	int unit = ((struct cfdata *)cf)->cf_unit;

	if (unit >= LPT_MAX)
		return(0);

	if ((int) i8255 == -1)
		i8255 = LPT_ADR(unit);

	i8255->port_control = LPT_PROBE_MODE;

	i8255->port_control = LPT_PROBE_CLR;
	if ((i8255->port_c & LPT_PROBE_MASK) != 0)
		return 0;
	
	i8255->port_control = LPT_PROBE_SET;
	if ((i8255->port_c & LPT_PROBE_MASK) == 0)
		return 0;

	i8255->port_control = LPT_PROBE_CLR;
	if ((i8255->port_c & LPT_PROBE_MASK) != 0)
		return 0;

	i8255->port_control = LPT_MODE;
	i8255->port_a = LPA_ACTIVE | LPA_NPRIME;

	ca->ca_addr = (int)i8255;
	if (ca->ca_irq == -1)
		ca->ca_irq = LPT_IRQ(unit);

	return 1;
}

static void
lptattach(parent, self, aux)
	struct device *parent, *self;
	void *aux;
{
	struct confargs *ca = aux;
	struct lpt_softc *sc = (struct lpt_softc *) self;
	volatile struct i8255 *i8255;

	printf("\n");

	sc->sc_irq = ca->ca_irq;
	i8255 = (volatile struct i8255 *)ca->ca_addr;
	i8255->port_control = LPT_MODE;
	i8255->port_a = LPA_ACTIVE | LPA_NPRIME;
	i8255->port_control = LPT_IRQDISABLE;

	sc->sc_state = 0;
	sc->sc_i8255 = i8255;

#if defined(INET) && defined(PLIP)
	plipattach(sc, self->dv_unit);
#endif
	intr_establish(sc->sc_irq, lptintr, sc, sc->sc_dev.dv_xname,
			IPL_ZERO, IPL_ZERO, LOW_LEVEL);
}

/*
 * Reset the printer, then wait until it's selected and not busy.
 */
int
lptopen(dev, flag, mode, p)
	dev_t dev;
	int flag;
	int mode;
	struct proc *p;
{
	struct lpt_softc *sc;
	volatile struct i8255 *i8255;
	u_char flags = LPTFLAGS(dev);
	int error;
	int spin;

	if (LPTUNIT(dev) >= lpt_cd.cd_ndevs)
		return ENXIO;

	sc = LPTSOFTC(LPTUNIT(dev));
	if (!sc)
		return ENXIO;

	if (sc->sc_state)
		return EBUSY;

	i8255 = sc->sc_i8255;
#if defined(INET) && defined(PLIP)
	if (sc->sc_ethercom.ec_if.if_flags & IFF_UP)
		return EBUSY;
#endif

	sc->sc_state = LPT_INIT;
	sc->sc_flags = flags;

	if ((flags & LPT_NOPRIME) == 0) {
		/* assert INIT for 100 usec to start up printer */
		i8255->port_a &= ~LPA_NPRIME;
		DELAY(100);
	}

	if (flags & LPT_AUTOLF)
		i8255->port_a |= LPA_ALF | LPA_SELECT | LPA_NPRIME;
	else
		i8255->port_a = (i8255->port_a & ~LPA_ALF)
				| LPA_SELECT | LPA_NPRIME;

	/* wait till ready (printer running diagnostics) */
	for (spin = 0; notready(i8255->port_c, sc); spin += STEP) {
		if (spin >= TIMEOUT) {
			sc->sc_state = 0;
			return EBUSY;
		}

		/* wait 1/4 second, give up if we get a signal */
		error = tsleep((caddr_t)sc, LPTPRI | PCATCH, "lptopen", STEP);
		if (error != EWOULDBLOCK) {
			sc->sc_state = 0;
			return error;
		}
	}

	sc->sc_inbuf  = malloc(LPT_BSIZE, M_DEVBUF, M_WAITOK);
	sc->sc_status =
	sc->sc_count  = 0;
	sc->sc_state  = LPT_OPEN;

	return 0;
}

static int
notready(status, sc)
	u_char status;
	struct lpt_softc *sc;
{
	status ^= LPT_INVERT;

	if (status != sc->sc_status) {
		if (status & LPC_NOPAPER)
			log(LOG_NOTICE, "%s: out of paper\n", sc->sc_dev.dv_xname);
		if (status & LPC_ONLINE)
			log(LOG_NOTICE, "%s: offline\n", sc->sc_dev.dv_xname);
		if (status & LPC_NERROR)
			log(LOG_NOTICE, "%s: output error\n", sc->sc_dev.dv_xname);
		if (status & LPC_NACK)
			log(LOG_NOTICE, "%s: NACK low\n", sc->sc_dev.dv_xname);
		if (status & LPC_NBUSY)
			log(LOG_NOTICE, "%s: NBUSY low\n", sc->sc_dev.dv_xname);
		sc->sc_status = status;
	}
	return status & LPT_MASK;
}

static void
lptout(arg)
	void *arg;
{
	struct lpt_softc *sc = arg;
	if (sc->sc_count > 0)
		sc->sc_i8255->port_control = LPT_IRQENABLE;
}

/*
 * Close the device, and free the local line buffer.
 */
int
lptclose(dev, flag, mode, p)
	dev_t dev;
	int flag;
	int mode;
	struct proc *p;
{
	struct lpt_softc *sc = LPTSOFTC(LPTUNIT(dev));

	if (sc->sc_count)
		(void) pushbytes(sc);

	sc->sc_i8255->port_control = LPT_IRQDISABLE;
	sc->sc_state = 0;
	free(sc->sc_inbuf, M_DEVBUF);

	return 0;
}

static int
pushbytes(sc)
	struct lpt_softc *sc;
{
	volatile struct i8255 *i8255 = sc->sc_i8255;
	int error;

	while (sc->sc_count > 0) {
		i8255->port_control = LPT_IRQENABLE;
		error = tsleep((caddr_t)sc, LPTPRI | PCATCH, "lptwrite", 0);
		if (error != 0) 
			return error;
	}
	return 0;
}

/* 
 * Copy a line from user space to a local buffer, then call pushbytes to
 * get the chars moved to the output queue.
 */
int
lptwrite(dev, uio, flags)
	dev_t dev;
	struct uio *uio;
	int flags;
{
	struct lpt_softc *sc = LPTSOFTC(LPTUNIT(dev));
	size_t n;
	int error = 0;

	if (sc->sc_count) return EBUSY;
	while ((n = min(LPT_BSIZE, uio->uio_resid)) != 0) {
		uiomove(sc->sc_cp = sc->sc_inbuf, n, uio);
		sc->sc_count = n;
		error = pushbytes(sc);
		if (error) {
			/*
			 * Return accurate residual if interrupted or timed
			 * out.
			 */
			uio->uio_resid += sc->sc_count;
			sc->sc_count = 0;
			return error;
		}
	}
	return 0;
}

/*
 * Handle printer interrupts which occur when the printer is ready to accept
 * another char.
 */
static void
lptintr(arg)
	void *arg;
{
	struct lpt_softc *sc = arg;
	volatile struct i8255 *i8255 = sc->sc_i8255;

#if defined(INET) && defined(PLIP)
	if (sc->sc_ethercom.ec_if.if_flags & IFF_UP) {
		i8255->port_a &= ~LPA_ACKENABLE;
		sc->sc_pending |= PLIP_IPENDING;
		softintr(sc->sc_ifsoftint);
		return;
	}
#endif

	if ((sc->sc_state & LPT_OPEN) == 0) {
		i8255->port_control = LPT_IRQDISABLE;
		return;
	}

	if (sc->sc_count) {
		/* is printer online and ready for output? */
		if (notready(i8255->port_c, sc)) {
			i8255->port_control = LPT_IRQDISABLE;
			timeout(lptout, sc, STEP);
			return;
		}
		/* send char */
		i8255->port_a &= ~LPA_ACTIVE;
		i8255->port_b = *sc->sc_cp++;
		i8255->port_a |= LPA_ACTIVE;
		sc->sc_count--;
	}

	if (sc->sc_count == 0) {
		/* none, wake up the top half to get more */
		i8255->port_control = LPT_IRQDISABLE;
		wakeup((caddr_t)sc);
	}
}

int
lptioctl(dev, cmd, data, flag, p)
	dev_t dev;
	u_long cmd;
	caddr_t data;
	int flag;
	struct proc *p;
{
	int error = 0;

	switch (cmd) {
	default:
		error = EINVAL;
	}

	return error;
}

#if defined(INET) && defined(PLIP)

static void
plipattach(sc, unit)
	struct lpt_softc *sc;
	int unit;
{
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	u_int8_t myaddr[ETHER_ADDR_LEN];

	sc->sc_ifbuf = NULL;
	sprintf(ifp->if_xname, "plip%d", unit);
	memset(myaddr, 0, sizeof(myaddr));
	ifp->if_softc = sc;
	ifp->if_start = plipstart;
	ifp->if_ioctl = plipioctl;
	ifp->if_watchdog = 0;
	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS;

	if_attach(ifp);
	ether_ifattach(ifp, myaddr);
	ifp->if_mtu = PLIPMTU;

#if NBPFILTER > 0
	bpfattach(&ifp->if_bpf, ifp, DLT_EN10MB, sizeof(struct ether_header));
#endif                 
	sc->sc_ifsoftint = intr_establish(SOFTINT, plipsoftint, sc,
				sc->sc_dev.dv_xname, IPL_NET, IPL_ZERO, 0);
}

/*
 * Process an ioctl request.
 */
static int
plipioctl(ifp, cmd, data)
	struct ifnet *ifp;
	u_long cmd;
	caddr_t data;
{
	struct proc *p = curproc;
	struct lpt_softc *sc = (struct lpt_softc *)(ifp->if_softc);
	volatile struct i8255 *i8255 = sc->sc_i8255;
	struct ifaddr *ifa = (struct ifaddr *)data;
	struct ifreq *ifr = (struct ifreq *)data; 
	struct sockaddr_dl *sdl;
	int error = 0;

	switch (cmd) {
	case SIOCSIFFLAGS:
		if (((ifp->if_flags & IFF_UP) == 0) &&
		    (ifp->if_flags & IFF_RUNNING)) {
		        ifp->if_flags &= ~IFF_RUNNING;
			sc->sc_i8255->port_control = LPT_MODE;
			i8255->port_a = LPA_ACTIVE | LPA_NPRIME;
			if (sc->sc_ifbuf)
				free(sc->sc_ifbuf, M_DEVBUF);
			sc->sc_ifbuf = NULL;
		}
		if (((ifp->if_flags & IFF_UP)) &&
		    ((ifp->if_flags & IFF_RUNNING) == 0)) {
			if (sc->sc_state) {
				error = EBUSY;
				break;
			}
			if (!sc->sc_ifbuf)
				sc->sc_ifbuf =
					malloc(ifp->if_mtu + ifp->if_hdrlen,
					       M_DEVBUF, M_WAITOK);
		        ifp->if_flags |= IFF_RUNNING;
			sc->sc_i8255->port_control = LPT_IRQDISABLE;
			sc->sc_i8255->port_b = 0;
			sc->sc_i8255->port_a |= LPA_ACKENABLE;
		}
		break;

	case SIOCSIFADDR:
		sdl = ifp->if_sadl;
		if (ifa->ifa_addr->sa_family == AF_INET) {
			if (!sc->sc_ifbuf)
				sc->sc_ifbuf =
					malloc(PLIPMTU + ifp->if_hdrlen,
					       M_DEVBUF, M_WAITOK);
			LLADDR(sdl)[0] = 0xfc;
			LLADDR(sdl)[1] = 0xfc;
			memcpy((caddr_t)&LLADDR(sdl)[2],
				(caddr_t)&IA_SIN(ifa)->sin_addr, 4);
#if defined(COMPAT_PLIP10)
			if (ifp->if_flags & IFF_LINK0) {
				int i;
				LLADDR(sdl)[0] = 0xfd;
				LLADDR(sdl)[1] = 0xfd;
				for (i = sc->sc_adrcksum = 0; i < 5; i++)
					sc->sc_adrcksum += LLADDR(sdl)[i];
				sc->sc_adrcksum *= 2;
			}
#endif
			ifp->if_flags |= IFF_RUNNING | IFF_UP;
			sc->sc_i8255->port_control = LPT_IRQDISABLE;
			sc->sc_i8255->port_b = 0;
			sc->sc_i8255->port_a |= LPA_ACKENABLE;
			arp_ifinit(ifp, ifa);
		} else
			error = EAFNOSUPPORT;
		break;

	case SIOCAIFADDR:
	case SIOCDIFADDR:
	case SIOCSIFDSTADDR:
		if (ifa->ifa_addr->sa_family != AF_INET)
			error = EAFNOSUPPORT;
		break;

	case SIOCSIFMTU:
        	if ((error = suser(p->p_ucred, &p->p_acflag)))
            		return(error);
		if (ifp->if_mtu != ifr->ifr_mtu) {
		        ifp->if_mtu = ifr->ifr_mtu;
			if (sc->sc_ifbuf) {
				free(sc->sc_ifbuf, M_DEVBUF);
				sc->sc_ifbuf =
					malloc(ifp->if_mtu + ifp->if_hdrlen,
					       M_DEVBUF, M_WAITOK);
			}
		}
		break;

	default:
		error = EINVAL;
	}
	return (error);
}

static void
plipsoftint(arg)
	void *arg;
{
	struct lpt_softc *sc = arg;
	int pending = sc->sc_pending;

	while (sc->sc_pending & PLIP_IPENDING) {
		pending |= sc->sc_pending;
		sc->sc_pending = 0;
		plipinput(sc);
	}

	if (pending & PLIP_OPENDING)
		plipoutput(sc);
}

#ifdef __OPTIMIZE__
int plipreceive __P((volatile struct i8255 *, u_char *, int))
	__asm("plipreceive");
__asm("
plipreceive:
	enter	[r3,r4,r5,r6,r7],0
	movqd	0,r0
	movd	8(fp),r1
	movd	12(fp),r2
	movd	16(fp),r3
	cmpqd	0,r3
	beq	5f

	movqd	0,r7
	movd	50000,r4

	.align	2,0xa2
0:	movb	8,r5
1:	movb	2(r1),r6
	andb	r6,r5
	cmpqb	0,r5
	beq	2f
	acbd	-1,r4,1b
	br	6f

	.align	2,0xa2
2:	movb	0x11,1(r1)
	lshb	-4,r6
	addd	r7,r0
	addqd	1,r2

	movb	8,r5
3:	movb	2(r1),r7
	bicb	r7,r5
	cmpqb	0,r5
	beq	4f
	acbd	-1,r4,3b
	br	6f

	.align	2,0xa2
4:	movqb	0x01,1(r1)
	andb	0xf0,r7
	orb	r6,r7
	movb	r7,-1(r2)
	acbd	-1,r3,0b

	addd	r7,r0
	andd	0xff,r0
5:	exit	[r3,r4,r5,r6,r7]
	ret	0

6:	movqd	-1,r0
	exit	[r3,r4,r5,r6,r7]
	ret	0
");
#else
static int
plipreceive(i8255, buf, len)
	volatile struct i8255 *i8255;
	u_char *buf;
	int len;
{
	int i;
	u_char cksum = 0, c;

	while (len--) {
		i = PLIPMXSPIN2;
		while ((i8255->port_c & LPC_NBUSY) != 0)
			if (i-- < 0) return -1;
		c = i8255->port_c >> 4;
		i8255->port_b = 0x11;
		while ((i8255->port_c & LPC_NBUSY) == 0)
			if (i-- < 0) return -1;
		c |= i8255->port_c & 0xf0;
		i8255->port_b = 0x01;
		cksum += (*buf++ = c);
	}
	return(cksum);
}
#endif

static void
pliprxenable(arg)
	void *arg;
{
	struct lpt_softc *sc = arg;
	volatile struct i8255 *i8255 = sc->sc_i8255;
	i8255->port_a |= LPA_ACKENABLE | LPA_ACTIVE;
}

static void
plipinput(sc)
	struct lpt_softc *sc;
{
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	volatile struct i8255 *i8255 = sc->sc_i8255;
	struct mbuf *m;
	struct ether_header *eh;
	u_char *p = sc->sc_ifbuf, minibuf[4];
	int s, len, cksum;

	if (!(i8255->port_c & LPC_NACK)) {
		i8255->port_a |= LPA_ACKENABLE;
		ifp->if_collisions++;
		return;
	}
	i8255->port_b = 0x01;
	i8255->port_a &= ~(LPA_ACKENABLE | LPA_ACTIVE);

	if (sc->sc_ifierrs)
		untimeout(pliprxenable, sc);

#if defined(COMPAT_PLIP10)
	if (ifp->if_flags & IFF_LINK0) {
		int c;
		if (plipreceive(i8255, minibuf, 3) < 0) goto err;
		len = (minibuf[1] << 8) | minibuf[2];
		if (len > (ifp->if_mtu + ifp->if_hdrlen)) goto err;

		switch (minibuf[0]) {
		case 0xfc:
			p[0] = p[ 6] = LLADDR(ifp->if_sadl)[0];
			p[1] = p[ 7] = LLADDR(ifp->if_sadl)[1];
			p[2] = p[ 8] = LLADDR(ifp->if_sadl)[2];
			p[3] = p[ 9] = LLADDR(ifp->if_sadl)[3];
			p[4] = p[10] = LLADDR(ifp->if_sadl)[4];
			p += 5;
			if ((cksum = plipreceive(i8255, p, 1)) < 0) goto err;
			p += 6;
			if ((c = plipreceive(i8255, p, len - 11)) < 0) goto err;
			cksum += c + sc->sc_adrcksum;
			c = p[1]; p[1] = p[2]; p[2] = c;
			cksum &= 0xff;
			break;
		case 0xfd:
			if ((cksum = plipreceive(i8255, p, len)) < 0) goto err;
			break;
		default:
			goto err;
		}
	} else
#endif
	{
		if (plipreceive(i8255, minibuf, 2) < 0) goto err;
		len = (minibuf[1] << 8) | minibuf[0];
		if (len > (ifp->if_mtu + ifp->if_hdrlen)) {
			log(LOG_NOTICE, "%s: packet (%x) > MTU\n", ifp->if_xname, len);
			goto err;
		}
		if ((cksum = plipreceive(i8255, p, len)) < 0) goto err;
	}

	if (plipreceive(i8255, minibuf, 1) < 0) goto err;
	if (cksum != minibuf[0]) {
		log(LOG_NOTICE, "%s: checksum error\n", ifp->if_xname);
		goto err;
	}
	i8255->port_b = 0x00;

	s = splimp();
	if ((m = m_devget(sc->sc_ifbuf, len, 0, ifp, NULL)) != NULL) {
		/* We assume that the header fit entirely in one mbuf. */
		eh = mtod(m, struct ether_header *);
#if NBPFILTER > 0
		/*
		 * Check if there's a BPF listener on this interface.
		 * If so, hand off the raw packet to bpf.
		 */
		if (ifp->if_bpf) {
			bpf_mtap(ifp->if_bpf, m);
		}
#endif
		(*ifp->if_input)(ifp, m);
	}
	splx(s);
	sc->sc_ifierrs = 0;
	ifp->if_ipackets++;
	i8255->port_a |= LPA_ACKENABLE | LPA_ACTIVE;
	return;

err:
	i8255->port_b = 0x00;

	if (sc->sc_ifierrs < PLIPMXERRS) {
		i8255->port_a |= LPA_ACKENABLE | LPA_ACTIVE;
	} else {
		/*
		 * We are not able to send or receive anything for now,
		 * so stop wasting our time and leave the interrupt
		 * disabled.
		 */
		if (sc->sc_ifierrs == PLIPMXERRS)
			log(LOG_NOTICE, "%s: rx hard error\n", ifp->if_xname);
		i8255->port_a |= LPA_ACTIVE;
		/* But we will retry from time to time. */
		timeout(pliprxenable, sc, PLIPRETRY * 10);
	}
	ifp->if_ierrors++;
	sc->sc_ifierrs++;
	return;
}

#ifdef __OPTIMIZE__
int pliptransmit __P((volatile struct i8255 *, u_char *, int))
	__asm("pliptransmit");
__asm("
pliptransmit:
	enter	[r3,r4,r5,r6,r7],0
	movqd	0,r0
	movd	8(fp),r1
	movd	12(fp),r2
	movd	16(fp),r3
	cmpqd	0,r3
	beq	5f

	movqd	0,r7
	movd	50000,r4

	.align	2,0xa2
0:	movb	8,r5
1:	movb	2(r1),r6
	bicb	r6,r5
	cmpqb	0,r5
	beq	2f
	acbd	-1,r4,1b
	br	6f

	.align	2,0xa2
2:	movb	0(r2),r7
	movb	0x0f,r5
	andb	r7,r5
	addqd	1,r2
	movb	r5,1(r1)
	orb	0x10,r5
	movb	r5,1(r1)

	movb	8,r5
3:	movb	2(r1),r6
	andb	r6,r5
	cmpqb	0,r5
	beq	4f
	acbd	-1,r4,3b
	br	6f

	.align	2,0xa2
4:	addd	r7,r0
	lshb	-4,r7
	movb	0x10,r5
	orb	r7,r5
	movb	r5,1(r1)
	movb	r7,1(r1)
	acbd	-1,r3,0b

	andd	0xff,r0
5:	exit	[r3,r4,r5,r6,r7]
	ret	0

6:	movqd	-1,r0
	exit	[r3,r4,r5,r6,r7]
	ret	0
");
#else
static int
pliptransmit(i8255. buf, len)
	volatile struct i8255 *i8255;
	u_char *buf;
	int len;
{
	int i;
	u_char cksum = 0, c;

	while (len--) {
		i = PLIPMXSPIN2;
		cksum += (c = *buf++);
		while ((i8255->port_c & LPC_NBUSY) == 0)
			if (i-- < 0) return -1;
		i8255->port_b = c & 0x0f;
		i8255->port_b = c & 0x0f | 0x10;
		c >>= 4;
		while ((i8255->port_c & LPC_NBUSY) != 0)
			if (i-- < 0) return -1;
		i8255->port_b = c | 0x10;
		i8255->port_b = c;
	}
	return(cksum);
}
#endif

/*
 * Setup output on interface.
 */
static void
plipstart(ifp)
	struct ifnet *ifp;
{
	struct lpt_softc *sc = (struct lpt_softc *)(ifp->if_softc);
	sc->sc_pending |= PLIP_OPENDING;
	softintr(sc->sc_ifsoftint);
}

static void
plipoutput(arg)
	void *arg;
{
	struct lpt_softc *sc = arg;
	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
	volatile struct i8255 *i8255 = sc->sc_i8255;
	struct mbuf *m0, *m;
	u_char minibuf[4], cksum;
	int len, i, s;

	if (ifp->if_flags & IFF_OACTIVE)
		return;
	ifp->if_flags |= IFF_OACTIVE;

	if (sc->sc_ifoerrs)
		untimeout(plipoutput, sc);

	for (;;) {
		s = splimp();
		IF_DEQUEUE(&ifp->if_snd, m0);
		splx(s);
		if (!m0)
			break;

#if NBPFILTER > 0
		if (ifp->if_bpf)
			bpf_mtap(ifp->if_bpf, m0);
#endif

		len = m0->m_pkthdr.len;

#if defined(COMPAT_PLIP10)
		if (ifp->if_flags & IFF_LINK0) {
			minibuf[0] = 3;
			minibuf[1] = 0xfd;
			minibuf[2] = len >> 8;
			minibuf[3] = len;
		} else
#endif
		{
			minibuf[0] = 2;
			minibuf[1] = len;
			minibuf[2] = len >> 8;
		}

		/* Trigger remote interrupt */
		i = PLIPMXSPIN1;
		do {
			if (sc->sc_pending & PLIP_IPENDING) {
				i8255->port_b = 0x00;
				sc->sc_pending = 0;
				plipinput(sc);
				i = PLIPMXSPIN1;
			} else if (i-- < 0)
				goto retry;
			/* Retrigger remote interrupt */
			i8255->port_b = 0x08;
		} while ((i8255->port_c & LPC_NERROR) == 0);
		i8255->port_a &= ~(LPA_ACKENABLE | LPA_ACTIVE);

		if (pliptransmit(i8255, minibuf + 1, minibuf[0]) < 0) goto retry;
		for (cksum = 0, m = m0; m; m = m->m_next) {
			i = pliptransmit(i8255, mtod(m, u_char *), m->m_len);
			if (i < 0) goto retry;
			cksum += i;
		}
		if (pliptransmit(i8255, &cksum, 1) < 0) goto retry;
		i = PLIPMXSPIN2;
		while ((i8255->port_c & LPC_NBUSY) == 0)
			if (i-- < 0) goto retry;
		i8255->port_b = 0x00;

		ifp->if_opackets++;
		ifp->if_obytes += len + 4;
		sc->sc_ifoerrs = 0;
		m_freem(m0);
		i8255->port_a |= LPA_ACKENABLE;
	}
	i8255->port_a |= LPA_ACTIVE;
	ifp->if_flags &= ~IFF_OACTIVE;
	return;

retry:
	if (i8255->port_c & LPC_NACK)
		ifp->if_collisions++;
	else
		ifp->if_oerrors++;

	ifp->if_flags &= ~IFF_OACTIVE;
	i8255->port_b = 0x00;

	if ((ifp->if_flags & (IFF_RUNNING | IFF_UP)) == (IFF_RUNNING | IFF_UP)
	    && sc->sc_ifoerrs < PLIPMXRETRY) {
		s = splimp();
		IF_PREPEND(&ifp->if_snd, m0);
		splx(s);
		timeout(plipoutput, sc, PLIPRETRY);
	} else {
		if (sc->sc_ifoerrs == PLIPMXRETRY) {
			log(LOG_NOTICE, "%s: tx hard error\n", ifp->if_xname);
		}
		m_freem(m0);
	}
	i8255->port_a |= LPA_ACKENABLE | LPA_ACTIVE;
	sc->sc_ifoerrs++;
}

#endif