xref: /src/sys/arch/atari/dev/ser.c

/*	$NetBSD: ser.c,v 1.3 1998/01/12 18:04:15 thorpej Exp $	*/

/*-
 * Copyright (c) 1997 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Leo Weppelman.
 *
 * The driver structure is based on the i386 com-driver from Charles M. Hannum.
 *
 * 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 the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``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 FOUNDATION OR CONTRIBUTORS
 * 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.
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <sys/tty.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/types.h>
#include <sys/device.h>

#include <m68k/asm_single.h>

#include <machine/iomap.h>
#include <machine/mfp.h>
#include <atari/atari/intr.h>
#include <atari/dev/ym2149reg.h>
#include <atari/dev/serreg.h>

/* #define SER_DEBUG */

#define	SERUNIT(x)	(minor(x))

/* XXX */
#define	CONSBAUD	9600
#define	CONSCFLAG	TTYDEF_CFLAG
/* end XXX */

/* Macros to clear/set/test flags. */
#define SET(t, f)	(t) |= (f)
#define CLR(t, f)	(t) &= ~(f)
#define ISSET(t, f)	((t) & (f))

#define	splserial()	spl6()

/* Buffer size for character buffer */
#define RXBUFSIZE 2048		/* More than enough..			*/
#define RXBUFMASK (RXBUFSIZE-1)	/* Only iff previous is a power of 2	*/
#define RXHIWAT   (RXBUFSIZE >> 2)

struct ser_softc {
	struct device	 sc_dev;
	struct tty	*sc_tty;

	int		 sc_overflows;
	int		 sc_floods;
	int		 sc_errors;

	u_char		 sc_hwflags;
	u_char		 sc_swflags;

	int		 sc_ospeed;		/* delay + timer-d data	*/
	u_char		 sc_imra;
	u_char		 sc_imrb;
	u_char		 sc_ucr;		/* Uart control		*/
	u_char		 sc_msr;		/* Modem status		*/
	u_char		 sc_tsr;		/* Tranceiver status	*/
	u_char		 sc_rsr;		/* Receiver status	*/
	u_char		 sc_mcr;		/* (Pseudo) Modem ctrl. */

	u_char		 sc_msr_delta;
	u_char		 sc_msr_mask;
	u_char		 sc_mcr_active;
	u_char		 sc_mcr_dtr, sc_mcr_rts, sc_msr_cts, sc_msr_dcd;

	int		 sc_r_hiwat;
 	volatile u_int	 sc_rbget;
 	volatile u_int	 sc_rbput;
	volatile u_int	 sc_rbavail;
 	u_char		 sc_rbuf[RXBUFSIZE];
	u_char		 sc_lbuf[RXBUFSIZE];

	volatile u_char	 sc_rx_blocked;
	volatile u_char	 sc_rx_ready;
	volatile u_char	 sc_tx_busy;
	volatile u_char	 sc_tx_done;
	volatile u_char	 sc_tx_stopped;
	volatile u_char	 sc_st_check;

 	u_char		*sc_tba;
 	int		 sc_tbc;
	int		 sc_heldtbc;

	volatile u_char	 sc_heldchange;
};

/*
 * For sc_hwflags:
 */
#define	SER_HW_CONSOLE	0x01

cdev_decl(ser);

void	ser_break __P((struct ser_softc *, int));
void	ser_hwiflow __P((struct ser_softc *, int));
void	ser_iflush __P((struct ser_softc *));
void	ser_loadchannelregs __P((struct ser_softc *));
void	ser_modem __P((struct ser_softc *, int));
void	serdiag __P((void *));
int	serhwiflow __P((struct tty *, int));
void	serinit __P((int));
void	serinitcons __P((int));
int	baud;
int	sermintr __P((void *));
int	sertrintr __P((void *));
int	serparam __P((struct tty *, struct termios *));
void	serstart __P((struct tty *));

struct consdev;
void	sercnprobe	__P((struct consdev *));
void	sercninit	__P((struct consdev *));
int	sercngetc	__P((dev_t));
void	sercnputc	__P((dev_t, int));
void	sercnpollc	__P((dev_t, int));

static void sermsrint __P((struct ser_softc *, struct tty*));
static void serrxint __P((struct ser_softc *, struct tty*));
static int serspeed __P((long));
static void sersoft __P((void *));
static void sertxint __P((struct ser_softc *, struct tty*));

static volatile int ser_softintr_scheduled = 0;
static int	sermajor;

/*
 * Autoconfig stuff
 */
static void serattach __P((struct device *, struct device *, void *));
static int  sermatch __P((struct device *, struct cfdata *, void *));

struct cfattach ser_ca = {
	sizeof(struct ser_softc), sermatch, serattach
};

extern struct cfdriver ser_cd;

/*ARGSUSED*/
static	int
sermatch(pdp, cfp, auxp)
struct	device	*pdp;
struct	cfdata	*cfp;
void		*auxp;
{
	if (!strcmp((char *)auxp, "ser") && cfp->cf_unit == 0)
		return (1);
	return (0);
}

/*ARGSUSED*/
static void
serattach(pdp, dp, auxp)
struct	device *pdp, *dp;
void	*auxp;
{
	struct ser_softc *sc = (void *)dp;

	if (intr_establish(1, USER_VEC, 0, (hw_ifun_t)sermintr, sc) == NULL)
		printf("serattach: Can't establish interrupt (1)\n");
	if (intr_establish(2, USER_VEC, 0, (hw_ifun_t)sermintr, sc) == NULL)
		printf("serattach: Can't establish interrupt (2)\n");
	if (intr_establish(14, USER_VEC, 0, (hw_ifun_t)sermintr, sc) == NULL)
		printf("serattach: Can't establish interrupt (14)\n");
	if (intr_establish(9, USER_VEC, 0, (hw_ifun_t)sertrintr, sc) == NULL)
		printf("serattach: Can't establish interrupt (9)\n");
	if (intr_establish(10, USER_VEC, 0, (hw_ifun_t)sertrintr, sc) == NULL)
		printf("serattach: Can't establish interrupt (10)\n");
	if (intr_establish(11, USER_VEC, 0, (hw_ifun_t)sertrintr, sc) == NULL)
		printf("serattach: Can't establish interrupt (11)\n");
	if (intr_establish(12, USER_VEC, 0, (hw_ifun_t)sertrintr, sc) == NULL)
		printf("serattach: Can't establish interrupt (12)\n");

	ym2149_rts(1);
	ym2149_dtr(1);

	/*
	 * Enable but mask interrupts...
	 * XXX: Look at edge-sensitivity for DCD/CTS interrupts.
	 */
	MFP->mf_ierb |= IB_SCTS|IB_SDCD;
	MFP->mf_iera |= IA_RRDY|IA_RERR|IA_TRDY|IA_TERR;
	MFP->mf_imrb &= ~(IB_SCTS|IB_SDCD);
	MFP->mf_imra &= ~(IA_RRDY|IA_RERR|IA_TRDY|IA_TERR);

#ifdef SERCONSOLE
	/*
	 * Activate serial console when DCD present...
	 */
	if (!(MFP->mf_gpip & MCR_DCD))
		SET(sc->sc_hwflags, SER_HW_CONSOLE);
#endif /* SERCONSOLE */

	printf("\n");
	if (ISSET(sc->sc_hwflags, SER_HW_CONSOLE)) {
		serinit(CONSBAUD);
		printf("%s: console\n", sc->sc_dev.dv_xname);
	}
}

#ifdef SER_DEBUG
void serstatus __P((struct ser_softc *, char *));
void
serstatus(sc, str)
	struct ser_softc *sc;
	char *str;
{
	struct tty *tp = sc->sc_tty;

	printf("%s: %s %sclocal  %sdcd %sts_carr_on %sdtr %stx_stopped\n",
	    sc->sc_dev.dv_xname, str,
	    ISSET(tp->t_cflag, CLOCAL) ? "+" : "-",
	    ISSET(sc->sc_msr, MCR_DCD) ? "+" : "-",
	    ISSET(tp->t_state, TS_CARR_ON) ? "+" : "-",
	    ISSET(sc->sc_mcr, MCR_DTR) ? "+" : "-",
	    sc->sc_tx_stopped ? "+" : "-");

	printf("%s: %s %scrtscts %scts %sts_ttstop  %srts %srx_blocked\n",
	    sc->sc_dev.dv_xname, str,
	    ISSET(tp->t_cflag, CRTSCTS) ? "+" : "-",
	    ISSET(sc->sc_msr, MCR_CTS) ? "+" : "-",
	    ISSET(tp->t_state, TS_TTSTOP) ? "+" : "-",
	    ISSET(sc->sc_mcr, MCR_RTS) ? "+" : "-",
	    sc->sc_rx_blocked ? "+" : "-");
}
#endif /* SER_DEBUG */

int
seropen(dev, flag, mode, p)
	dev_t dev;
	int flag, mode;
	struct proc *p;
{
	int unit = SERUNIT(dev);
	struct ser_softc *sc;
	struct tty *tp;
	int s, s2;
	int error = 0;

	if (unit >= ser_cd.cd_ndevs)
		return (ENXIO);
	sc = ser_cd.cd_devs[unit];
	if (!sc)
		return (ENXIO);

	if (!sc->sc_tty) {
		tp = sc->sc_tty = ttymalloc();
		tty_attach(tp);
	} else
		tp = sc->sc_tty;

	if (ISSET(tp->t_state, TS_ISOPEN) &&
	    ISSET(tp->t_state, TS_XCLUDE) &&
	    p->p_ucred->cr_uid != 0)
		return (EBUSY);

	s = spltty();

	/* We need to set this early for the benefit of sersoft(). */
	SET(tp->t_state, TS_WOPEN);

	/*
	 * Do the following if this is a first open.
	 */
	if (!ISSET(tp->t_state, TS_ISOPEN)) {
	    struct termios t;

	    /* Turn on interrupts. */
	    sc->sc_imra = IA_RRDY|IA_RERR|IA_TRDY|IA_TERR;
	    sc->sc_imrb = IB_SCTS|IB_SDCD;
	    single_inst_bset_b(MFP->mf_imra, sc->sc_imra);
	    single_inst_bset_b(MFP->mf_imrb, sc->sc_imrb);

	    /* Fetch the current modem control status, needed later. */
	    sc->sc_msr = ~MFP->mf_gpip & (IO_SDCD|IO_SCTS|IO_SRI);

	    /* Add some entry points needed by the tty layer. */
	    tp->t_oproc = serstart;
	    tp->t_param = serparam;
	    tp->t_hwiflow = serhwiflow;
	    tp->t_dev = dev;

	    /*
	     * Initialize the termios status to the defaults.  Add in the
	     * sticky bits from TIOCSFLAGS.
	     */
	    t.c_ispeed = 0;
	    if (ISSET(sc->sc_hwflags, SER_HW_CONSOLE)) {
		    t.c_ospeed = CONSBAUD;
		    t.c_cflag  = CONSCFLAG;
	    }
	    else {
		    t.c_ospeed = TTYDEF_SPEED;
		    t.c_cflag = TTYDEF_CFLAG;
	    }
	    if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
		    SET(t.c_cflag, CLOCAL);
	    if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
		    SET(t.c_cflag, CRTSCTS);
	    if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
		    SET(t.c_cflag, MDMBUF);
	    tp->t_iflag = TTYDEF_IFLAG;
	    tp->t_oflag = TTYDEF_OFLAG;
	    tp->t_lflag = TTYDEF_LFLAG;
	    ttychars(tp);
	    (void) serparam(tp, &t);
	    ttsetwater(tp);

	    s2 = splserial();

	    /*
	     * Turn on DTR.  We must always do this, even if carrier is not
	     * present, because otherwise we'd have to use TIOCSDTR
	     * immediately after setting CLOCAL.  We will drop DTR only on
	     * the next high-low transition of DCD, or by explicit request.
	     */
	    ser_modem(sc, 1);

	    /* Clear the input ring, and unblock. */
	    sc->sc_rbput = sc->sc_rbget = 0;
	    sc->sc_rbavail = RXBUFSIZE;
	    ser_iflush(sc);
	    sc->sc_rx_blocked = 0;
	    ser_hwiflow(sc, 0);

#ifdef SER_DEBUG
	    serstatus(sc, "seropen  ");
#endif

	    splx(s2);
	}
	error = 0;

	/* If we're doing a blocking open... */
	if (!ISSET(flag, O_NONBLOCK))
		/* ...then wait for carrier. */
		while (!ISSET(tp->t_state, TS_CARR_ON) &&
		    !ISSET(tp->t_cflag, CLOCAL | MDMBUF)) {
			error = ttysleep(tp, &tp->t_rawq, TTIPRI | PCATCH,
			    ttopen, 0);
			if (error) {
				/*
				 * If the open was interrupted and nobody
				 * else has the device open, then hang up.
				 */
				if (!ISSET(tp->t_state, TS_ISOPEN)) {
					ser_modem(sc, 0);
					CLR(tp->t_state, TS_WOPEN);
					ttwakeup(tp);
				}
				break;
			}
			SET(tp->t_state, TS_WOPEN);
		}

	splx(s);
	if (error == 0)
		error = (*linesw[tp->t_line].l_open)(dev, tp);
	return (error);
}

int
serclose(dev, flag, mode, p)
	dev_t		dev;
	int		flag, mode;
	struct proc	*p;
{
	int unit = SERUNIT(dev);
	struct ser_softc *sc = ser_cd.cd_devs[unit];
	struct tty *tp = sc->sc_tty;
	int s;

	/* XXX This is for cons.c. */
	if (!ISSET(tp->t_state, TS_ISOPEN))
		return (0);

	(*linesw[tp->t_line].l_close)(tp, flag);
	ttyclose(tp);

	/* If we were asserting flow control, then deassert it. */
	sc->sc_rx_blocked = 1;
	ser_hwiflow(sc, 1);

	/* Clear any break condition set with TIOCSBRK. */
	ser_break(sc, 0);

	/*
	 * Hang up if necessary.  Wait a bit, so the other side has time to
	 * notice even if we immediately open the port again.
	 */
	if (ISSET(tp->t_cflag, HUPCL)) {
		ser_modem(sc, 0);
		(void) tsleep(sc, TTIPRI, ttclos, hz);
	}

	s = splserial();
	/* Turn off interrupts. */
	CLR(sc->sc_imra, IA_RRDY|IA_RERR|IA_TRDY|IA_TERR);
	CLR(sc->sc_imrb, IB_SCTS|IB_SDCD);
	single_inst_bclr_b(MFP->mf_imrb, IB_SCTS|IB_SDCD);
	single_inst_bclr_b(MFP->mf_imra, IA_RRDY|IA_RERR|IA_TRDY|IA_TERR);
	splx(s);

	return (0);
}

int
serread(dev, uio, flag)
	dev_t dev;
	struct uio *uio;
	int flag;
{
	struct ser_softc *sc = ser_cd.cd_devs[SERUNIT(dev)];
	struct tty *tp = sc->sc_tty;

	return ((*linesw[tp->t_line].l_read)(tp, uio, flag));
}

int
serwrite(dev, uio, flag)
	dev_t dev;
	struct uio *uio;
	int flag;
{
	struct ser_softc *sc = ser_cd.cd_devs[SERUNIT(dev)];
	struct tty *tp = sc->sc_tty;

	return ((*linesw[tp->t_line].l_write)(tp, uio, flag));
}

struct tty *
sertty(dev)
	dev_t dev;
{
	struct ser_softc *sc = ser_cd.cd_devs[SERUNIT(dev)];
	struct tty *tp = sc->sc_tty;

	return (tp);
}

int
serioctl(dev, cmd, data, flag, p)
	dev_t dev;
	u_long cmd;
	caddr_t data;
	int flag;
	struct proc *p;
{
	int unit = SERUNIT(dev);
	struct ser_softc *sc = ser_cd.cd_devs[unit];
	struct tty *tp = sc->sc_tty;
	int error;

	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
	if (error >= 0)
		return (error);

	error = ttioctl(tp, cmd, data, flag, p);
	if (error >= 0)
		return (error);

	switch (cmd) {
	case TIOCSBRK:
		ser_break(sc, 1);
		break;

	case TIOCCBRK:
		ser_break(sc, 0);
		break;

	case TIOCSDTR:
		ser_modem(sc, 1);
		break;

	case TIOCCDTR:
		ser_modem(sc, 0);
		break;

	case TIOCGFLAGS:
		*(int *)data = sc->sc_swflags;
		break;

	case TIOCSFLAGS:
		error = suser(p->p_ucred, &p->p_acflag);
		if (error)
			return (error);
		sc->sc_swflags = *(int *)data;
		break;

	case TIOCMSET:
	case TIOCMBIS:
	case TIOCMBIC:
	case TIOCMGET:
	default:
		return (ENOTTY);
	}

#ifdef SER_DEBUG
		serstatus(sc, "serioctl ");
#endif

	return (0);
}

void
ser_break(sc, onoff)
	struct ser_softc *sc;
	int onoff;
{
	int s;

	s = splserial();
	if (onoff)
		SET(sc->sc_tsr, TSR_SBREAK);
	else
		CLR(sc->sc_tsr, TSR_SBREAK);

	if (!sc->sc_heldchange) {
		if (sc->sc_tx_busy) {
			sc->sc_heldtbc = sc->sc_tbc;
			sc->sc_tbc = 0;
			sc->sc_heldchange = 1;
		} else
			ser_loadchannelregs(sc);
	}
	splx(s);
}

void
ser_modem(sc, onoff)
	struct ser_softc *sc;
	int onoff;
{
	int s;

	s = splserial();
	if (onoff)
		SET(sc->sc_mcr, sc->sc_mcr_dtr);
	else
		CLR(sc->sc_mcr, sc->sc_mcr_dtr);

	if (!sc->sc_heldchange) {
		if (sc->sc_tx_busy) {
			sc->sc_heldtbc = sc->sc_tbc;
			sc->sc_tbc = 0;
			sc->sc_heldchange = 1;
		} else
			ser_loadchannelregs(sc);
	}
	splx(s);
}

int
serparam(tp, t)
	struct tty *tp;
	struct termios *t;
{
	struct ser_softc *sc = ser_cd.cd_devs[SERUNIT(tp->t_dev)];
	int ospeed = serspeed(t->c_ospeed);
	u_char ucr;
	int s;

	/* check requested parameters */
	if (ospeed < 0)
		return (EINVAL);
	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
		return (EINVAL);

	sc->sc_rsr = RSR_ENAB;
	sc->sc_tsr = TSR_ENAB;

	ucr = UCR_CLKDIV;

	switch (ISSET(t->c_cflag, CSIZE)) {
	case CS5:
		SET(ucr, UCR_5BITS);
		break;
	case CS6:
		SET(ucr, UCR_6BITS);
		break;
	case CS7:
		SET(ucr, UCR_7BITS);
		break;
	case CS8:
		SET(ucr, UCR_8BITS);
		break;
	}
	if (ISSET(t->c_cflag, PARENB)) {
		SET(ucr, UCR_PENAB);
		if (!ISSET(t->c_cflag, PARODD))
			SET(ucr, UCR_PEVEN);
	}
	if (ISSET(t->c_cflag, CSTOPB))
		SET(ucr, UCR_STOPB2);
	else
		SET(ucr, UCR_STOPB1);

	s = splserial();

	sc->sc_ucr = ucr;

	/*
	 * For the console, always force CLOCAL and !HUPCL, so that the port
	 * is always active.
	 */
	if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
	    ISSET(sc->sc_hwflags, SER_HW_CONSOLE)) {
		SET(t->c_cflag, CLOCAL);
		CLR(t->c_cflag, HUPCL);
	}

	/*
	 * If we're not in a mode that assumes a connection is present, then
	 * ignore carrier changes.
	 */
	if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
		sc->sc_msr_dcd = 0;
	else
		sc->sc_msr_dcd = MCR_DCD;
	/*
	 * Set the flow control pins depending on the current flow control
	 * mode.
	 */
	if (ISSET(t->c_cflag, CRTSCTS)) {
		sc->sc_mcr_dtr = MCR_DTR;
		sc->sc_mcr_rts = MCR_RTS;
		sc->sc_msr_cts = MCR_CTS;
		sc->sc_r_hiwat = RXHIWAT;
	} else if (ISSET(t->c_cflag, MDMBUF)) {
		/*
		 * For DTR/DCD flow control, make sure we don't toggle DTR for
		 * carrier detection.
		 */
		sc->sc_mcr_dtr = 0;
		sc->sc_mcr_rts = MCR_DTR;
		sc->sc_msr_cts = MCR_DCD;
		sc->sc_r_hiwat = RXHIWAT;
	} else {
		/*
		 * If no flow control, then always set RTS.  This will make
		 * the other side happy if it mistakenly thinks we're doing
		 * RTS/CTS flow control.
		 */
		sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
		sc->sc_mcr_rts = 0;
		sc->sc_msr_cts = 0;
		sc->sc_r_hiwat = 0;
		if (ISSET(sc->sc_mcr, MCR_DTR))
			SET(sc->sc_mcr, MCR_RTS);
		else
			CLR(sc->sc_mcr, MCR_RTS);
	}
	sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;

#if 0
	if (ospeed == 0)
		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
	else
		SET(sc->sc_mcr, sc->sc_mcr_dtr);
#endif

	sc->sc_ospeed = ospeed;

	/* and copy to tty */
	tp->t_ispeed = 0;
	tp->t_ospeed = t->c_ospeed;
	tp->t_cflag = t->c_cflag;

	if (!sc->sc_heldchange) {
		if (sc->sc_tx_busy) {
			sc->sc_heldtbc = sc->sc_tbc;
			sc->sc_tbc = 0;
			sc->sc_heldchange = 1;
		} else
			ser_loadchannelregs(sc);
	}

	splx(s);

	/*
	 * Update the tty layer's idea of the carrier bit, in case we changed
	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that if we
	 * lose carrier while carrier detection is on.
	 */
	(void) (*linesw[tp->t_line].l_modem)(tp, ISSET(sc->sc_msr, MCR_DCD));

#ifdef SER_DEBUG
	serstatus(sc, "serparam ");
#endif

	/* XXXXX FIX ME */
	/* Block or unblock as needed. */
	if (!ISSET(t->c_cflag, CHWFLOW)) {
		if (sc->sc_rx_blocked) {
			sc->sc_rx_blocked = 0;
			ser_hwiflow(sc, 0);
		}
		if (sc->sc_tx_stopped) {
			sc->sc_tx_stopped = 0;
			serstart(tp);
		}
	} else {
#if 0
		sermsrint(sc, tp);
#endif
	}

	return (0);
}

void
ser_iflush(sc)
	struct ser_softc *sc;
{
	u_char	tmp;

	/* flush any pending I/O */
	while (ISSET(MFP->mf_rsr, RSR_CIP|RSR_BFULL))
		tmp = MFP->mf_udr;
}

void
ser_loadchannelregs(sc)
	struct ser_softc *sc;
{
	/* XXXXX necessary? */
	ser_iflush(sc);

	/*
	 * No interrupts please...
	 */
if((MFP->mf_imra & (IA_RRDY|IA_RERR|IA_TRDY|IA_TERR)) != sc->sc_imra) {
printf("loadchannelregs: mf_imra: %x sc_imra: %x\n", (u_int)MFP->mf_imra,
						     (u_int)sc->sc_imra);
}
if((MFP->mf_imrb & (IB_SCTS|IB_SDCD)) != sc->sc_imrb) {
printf("loadchannelregs: mf_imrb: %x sc_imrb: %x\n", (u_int)MFP->mf_imrb,
						     (u_int)sc->sc_imrb);
}
	single_inst_bclr_b(MFP->mf_imra, IA_RRDY|IA_RERR|IA_TRDY|IA_TERR);
	single_inst_bclr_b(MFP->mf_imrb, IB_SCTS|IB_SDCD);

	MFP->mf_ucr = sc->sc_ucr;
	MFP->mf_rsr = sc->sc_rsr;
	MFP->mf_tsr = sc->sc_tsr;

	single_inst_bclr_b(MFP->mf_tcdcr, 0x07);
	MFP->mf_tddr  = sc->sc_ospeed;
	single_inst_bset_b(MFP->mf_tcdcr, (sc->sc_ospeed >> 8) & 0x0f);

	sc->sc_mcr_active = sc->sc_mcr;

	if (machineid & ATARI_HADES) {
		/* PCB fault, wires exchanged..... */
		ym2149_rts(!(sc->sc_mcr_active & MCR_DTR));
		ym2149_dtr(!(sc->sc_mcr_active & MCR_RTS));
	}
	else {
		ym2149_rts(!(sc->sc_mcr_active & MCR_RTS));
		ym2149_dtr(!(sc->sc_mcr_active & MCR_DTR));
	}

	single_inst_bset_b(MFP->mf_imra, sc->sc_imra);
	single_inst_bset_b(MFP->mf_imrb, sc->sc_imrb);
}

int
serhwiflow(tp, block)
	struct tty *tp;
	int block;
{
	struct ser_softc *sc = ser_cd.cd_devs[SERUNIT(tp->t_dev)];
	int s;

	if (sc->sc_mcr_rts == 0)
		return (0);

	s = splserial();
	if (block) {
		/*
		 * The tty layer is asking us to block input.
		 * If we already did it, just return TRUE.
		 */
		if (sc->sc_rx_blocked)
			goto out;
		sc->sc_rx_blocked = 1;
	} else {
		/*
		 * The tty layer is asking us to resume input.
		 * The input ring is always empty by now.
		 */
		sc->sc_rx_blocked = 0;
	}
	ser_hwiflow(sc, block);
out:
	splx(s);
	return (1);
}

/*
 * (un)block input via hw flowcontrol
 */
void
ser_hwiflow(sc, block)
	struct ser_softc *sc;
	int block;
{
	if (sc->sc_mcr_rts == 0)
		return;

	if (block) {
		CLR(sc->sc_mcr, sc->sc_mcr_rts);
		CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
	} else {
		SET(sc->sc_mcr, sc->sc_mcr_rts);
		SET(sc->sc_mcr_active, sc->sc_mcr_rts);
	}
	if (machineid & ATARI_HADES) {
		/* PCB fault, wires exchanged..... */
		ym2149_dtr(sc->sc_mcr_active & MCR_RTS);
	}
	else {
		ym2149_rts(sc->sc_mcr_active & MCR_RTS);
	}
}

void
serstart(tp)
	struct tty *tp;
{
	struct ser_softc *sc = ser_cd.cd_devs[SERUNIT(tp->t_dev)];
	int s;

	s = spltty();
	if (ISSET(tp->t_state, TS_BUSY))
		goto out;
	if (ISSET(tp->t_state, TS_TIMEOUT | TS_TTSTOP))
		goto stopped;

	if (sc->sc_tx_stopped)
		goto stopped;

	if (tp->t_outq.c_cc <= tp->t_lowat) {
		if (ISSET(tp->t_state, TS_ASLEEP)) {
			CLR(tp->t_state, TS_ASLEEP);
			wakeup(&tp->t_outq);
		}
		selwakeup(&tp->t_wsel);
		if (tp->t_outq.c_cc == 0)
			goto stopped;
	}

	/* Grab the first contiguous region of buffer space. */
	{
		u_char *tba;
		int tbc;

		tba = tp->t_outq.c_cf;
		tbc = ndqb(&tp->t_outq, 0);

		(void)splserial();

		sc->sc_tba = tba;
		sc->sc_tbc = tbc;
	}

	SET(tp->t_state, TS_BUSY);
	sc->sc_tx_busy = 1;

	/* Enable transmit completion interrupts if necessary. */
	if (!ISSET(sc->sc_imra, IA_TRDY)) {
		SET(sc->sc_imra, IA_TRDY|IA_TERR);
		single_inst_bset_b(MFP->mf_imra, IA_TRDY|IA_TERR);
	}

	/* Output the first char */
	MFP->mf_udr = *sc->sc_tba;
	sc->sc_tbc --;
	sc->sc_tba ++;

	splx(s);
	return;

stopped:
	/* Disable transmit completion interrupts if necessary. */
	if (ISSET(sc->sc_imra, IA_TRDY)) {
		CLR(sc->sc_imra, IA_TRDY|IA_TERR);
		single_inst_bclr_b(MFP->mf_imra, IA_TRDY|IA_TERR);
	}
out:
	splx(s);
	return;
}

/*
 * Stop output on a line.
 */
void
serstop(tp, flag)
	struct tty *tp;
	int flag;
{
	struct ser_softc *sc = ser_cd.cd_devs[SERUNIT(tp->t_dev)];
	int s;

	s = splserial();
	if (ISSET(tp->t_state, TS_BUSY)) {
		/* Stop transmitting at the next chunk. */
		sc->sc_tbc = 0;
		sc->sc_heldtbc = 0;
		if (!ISSET(tp->t_state, TS_TTSTOP))
			SET(tp->t_state, TS_FLUSH);
	}
	splx(s);
}

void
serdiag(arg)
	void *arg;
{
	struct ser_softc *sc = arg;
	int overflows, floods;
	int s;

	s = splserial();
	overflows = sc->sc_overflows;
	sc->sc_overflows = 0;
	floods = sc->sc_floods;
	sc->sc_floods = 0;
	sc->sc_errors = 0;
	splx(s);

	log(LOG_WARNING,
	    "%s: %d silo overflow%s, %d ibuf flood%s\n",
	    sc->sc_dev.dv_xname,
	    overflows, overflows == 1 ? "" : "s",
	    floods, floods == 1 ? "" : "s");
}

static void
serrxint(sc, tp)
	struct ser_softc	*sc;
	struct tty		*tp;
{
	u_int	get, cc, scc;
	int	code;
	u_char	rsr;
	int	s;
	static int lsrmap[8] = {
		0,      TTY_PE,
		TTY_FE, TTY_PE|TTY_FE,
		TTY_FE, TTY_PE|TTY_FE,
		TTY_FE, TTY_PE|TTY_FE
	};

	get = sc->sc_rbget;
	scc = cc = RXBUFSIZE - sc->sc_rbavail;

	if (cc == RXBUFSIZE) {
		sc->sc_floods++;
		if (sc->sc_errors++ == 0)
			timeout(serdiag, sc, 60 * hz);
	}

	while (cc--) {
		rsr = sc->sc_lbuf[get];
		if (ISSET(rsr, RSR_BREAK)) {
#ifdef DDB
			if (ISSET(sc->sc_hwflags, SER_HW_CONSOLE))
				Debugger();
#endif
		}
		else if (ISSET(rsr, RSR_OERR)) {
			sc->sc_overflows++;
			if (sc->sc_errors++ == 0)
				timeout(serdiag, sc, 60 * hz);
		}
		code = sc->sc_rbuf[get] |
		    lsrmap[(rsr & (RSR_BREAK|RSR_FERR|RSR_PERR)) >> 3];
		(*linesw[tp->t_line].l_rint)(code, tp);
		get = (get + 1) & RXBUFMASK;
	}

	sc->sc_rbget = get;
	s = splserial();
	sc->sc_rbavail += scc;
	/*
	 * Buffers should be ok again, release possible block, but only if the
	 * tty layer isn't blocking too.
	 */
	if (sc->sc_rx_blocked && !ISSET(tp->t_state, TS_TBLOCK)) {
		sc->sc_rx_blocked = 0;
		ser_hwiflow(sc, 0);
	}
	splx(s);
}

static void
sertxint(sc, tp)
	struct ser_softc	*sc;
	struct tty		*tp;
{

	CLR(tp->t_state, TS_BUSY);
	if (ISSET(tp->t_state, TS_FLUSH))
		CLR(tp->t_state, TS_FLUSH);
	else
		ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
	(*linesw[tp->t_line].l_start)(tp);
}

static void
sermsrint(sc, tp)
	struct ser_softc	*sc;
	struct tty		*tp;
{
	u_char msr, delta;
	int s;

	s = splserial();
	msr = sc->sc_msr;
	delta = sc->sc_msr_delta;
	sc->sc_msr_delta = 0;
	splx(s);

	if (ISSET(delta, sc->sc_msr_dcd)) {
		/*
		 * Inform the tty layer that carrier detect changed.
		 */
		(void) (*linesw[tp->t_line].l_modem)(tp, ISSET(msr, MCR_DCD));
	}

	if (ISSET(delta, sc->sc_msr_cts)) {
		/* Block or unblock output according to flow control. */
		if (ISSET(msr, sc->sc_msr_cts)) {
			sc->sc_tx_stopped = 0;
			(*linesw[tp->t_line].l_start)(tp);
		} else {
			sc->sc_tx_stopped = 1;
			serstop(tp, 0);
		}
	}

#ifdef SER_DEBUG
	serstatus(sc, "sermsrint");
#endif
}

void
sersoft(arg)
	void *arg;
{
	struct ser_softc *sc = arg;
	struct tty	*tp;

	ser_softintr_scheduled = 0;

	tp = sc->sc_tty;
	if (tp == NULL || !ISSET(tp->t_state, TS_ISOPEN | TS_WOPEN))
		return;

	if (sc->sc_rx_ready) {
		sc->sc_rx_ready = 0;
		serrxint(sc, tp);
	}

	if (sc->sc_st_check) {
		sc->sc_st_check = 0;
		sermsrint(sc, tp);
	}

	if (sc->sc_tx_done) {
		sc->sc_tx_done = 0;
		sertxint(sc, tp);
	}
}

int
sermintr(arg)
void	*arg;
{
	struct ser_softc *sc = arg;
	u_char	msr, delta;

	msr = ~MFP->mf_gpip;
	delta = msr ^ sc->sc_msr;
	sc->sc_msr  = sc->sc_msr & ~(MCR_CTS|MCR_DCD|MCR_RI);
	sc->sc_msr |= msr & (MCR_CTS|MCR_DCD|MCR_RI);

	if (ISSET(delta, sc->sc_msr_mask)) {
		sc->sc_msr_delta |= delta;

		/*
		 * Stop output immediately if we lose the output
		 * flow control signal or carrier detect.
		 */
		if (ISSET(~msr, sc->sc_msr_mask)) {
			sc->sc_tbc = 0;
			sc->sc_heldtbc = 0;
#ifdef SER_DEBUG
			serstatus(sc, "sermintr  ");
#endif
		}

		sc->sc_st_check = 1;
	}
	if (!ser_softintr_scheduled)
		add_sicallback((si_farg)sersoft, sc, 0);
	return 1;
}

int
sertrintr(arg)
	void	*arg;
{
	struct ser_softc *sc = arg;
	u_int	put, cc;
	u_char	rsr, tsr;

	put = sc->sc_rbput;
	cc = sc->sc_rbavail;

	rsr = MFP->mf_rsr;
	if (ISSET(rsr, RSR_BFULL|RSR_BREAK)) {
		for (; ISSET(rsr, RSR_BFULL|RSR_BREAK) && cc > 0; cc--) {
			sc->sc_rbuf[put] = MFP->mf_udr;
			sc->sc_lbuf[put] = rsr;
			put = (put + 1) & RXBUFMASK;
			if ((rsr & RSR_BREAK) && (MFP->mf_rsr & RSR_BREAK))
				rsr = 0;
			else rsr = MFP->mf_rsr;
		}
		/*
		 * Current string of incoming characters ended because
		 * no more data was available. Schedule a receive event
		 * if any data was received. Drop any characters that
		 * we couldn't handle.
		 */
		sc->sc_rbput    = put;
		sc->sc_rbavail  = cc;
		sc->sc_rx_ready = 1;
		/*
		 * See if we are in danger of overflowing a buffer. If
		 * so, use hardware flow control to ease the pressure.
		 */
		if (sc->sc_rx_blocked == 0 &&
		    cc < sc->sc_r_hiwat) {
			sc->sc_rx_blocked = 1;
			ser_hwiflow(sc, 1);
		}
		/*
		 * If we're out of space, throw away any further input.
		 */
		if (!cc) {
			while (ISSET(rsr, RSR_BFULL|RSR_BREAK)) {
				rsr = MFP->mf_udr;
				rsr = MFP->mf_rsr;
			}
		}
	}

	/*
	 * Done handling any receive interrupts. See if data can be
	 * transmitted as well. Schedule tx done event if no data left
	 * and tty was marked busy.
	 */
	tsr = MFP->mf_tsr;
	if (ISSET(tsr, TSR_BE)) {
		/*
		 * If we've delayed a parameter change, do it now, and restart
		 * output.
		 */
		if (sc->sc_heldchange) {
			ser_loadchannelregs(sc);
			sc->sc_heldchange = 0;
			sc->sc_tbc = sc->sc_heldtbc;
			sc->sc_heldtbc = 0;
		}
		/* Output the next character, if any. */
		if (sc->sc_tbc > 0) {
			MFP->mf_udr = *sc->sc_tba;
			sc->sc_tbc --;
			sc->sc_tba ++;
		} else if (sc->sc_tx_busy) {
			sc->sc_tx_busy = 0;
			sc->sc_tx_done = 1;
		}
	}

	if (!ser_softintr_scheduled)
		add_sicallback((si_farg)sersoft, sc, 0);
	return 1;
}

static int
serspeed(speed)
	long speed;
{
#define	divrnd(n, q)	(((n)*2/(q)+1)/2)	/* divide and round off */

	int div, x, err;

	if (speed <= 0)
		return (-1);

	for (div = 4; div <= 64; div *= 4) {
		x = divrnd((SER_FREQ / div), speed);

		/*
		 * The value must fit in the timer-d dataregister. If
		 * not, try another delay-mode.
		 */
		if ((x/2) > 255)
			continue;

		/*
		 * Baudrate to high for the interface or cannot be made
		 * within tolerance.
		 */
		if (x <= 0)
			return (-1);

		err = divrnd((SER_FREQ / div) * 1000, speed * x) - 1000;
		if (err < 0)
			err = -err;
		if (err > SER_TOLERANCE)
			continue;

		/*
		 * Translate 'div' to delay-code
		 */
		if (div == 4)
			div = 1;
		else if (div == 16)
			div = 3;
		else if (div == 64)
			div = 5;

		return ((x/2) | (div << 8));
	}
	return (-1);

#undef	divrnd(n, q)
}

/*
 * Following are all routines needed for SER to act as console
 */
#include <dev/cons.h>

void
sercnprobe(cp)
	struct consdev *cp;
{
	/*
	 * Activate serial console when DCD present...
	 */
	if (MFP->mf_gpip & MCR_DCD) {
		cp->cn_pri = CN_DEAD;
		return;
	}
	for (sermajor = 0; sermajor < nchrdev; sermajor++)
		if (cdevsw[sermajor].d_open == seropen)
			break;

	/* initialize required fields */
	cp->cn_dev = makedev(sermajor, 0); /* XXX: LWP What unit? */
#ifdef SERCONSOLE
	cp->cn_pri = CN_REMOTE;	/* Force a serial port console */
#else
	cp->cn_pri = CN_NORMAL;
#endif
}

void
sercninit(cp)
	struct consdev *cp;
{
	serinitcons(CONSBAUD);
}

/*
 * Initialize UART to known state.
 */
void
serinit(baud)
int	baud;
{
	int ospeed = serspeed(baud);

	MFP->mf_ucr = UCR_CLKDIV|UCR_8BITS|UCR_STOPB1;
	MFP->mf_rsr = RSR_ENAB;
	MFP->mf_tsr = TSR_ENAB;

	single_inst_bclr_b(MFP->mf_tcdcr, 0x07);
	MFP->mf_tddr  = ospeed;
	single_inst_bset_b(MFP->mf_tcdcr, (ospeed >> 8) & 0x0f);
}

/*
 * Set UART for console use. Do normal init, then enable interrupts.
 */
void
serinitcons(baud)
int	baud;
{
	serinit(baud);

	/* Set rts/dtr */
	ym2149_rts(0);
	ym2149_dtr(0);

	single_inst_bset_b(MFP->mf_imra, (IA_RRDY|IA_RERR|IA_TRDY|IA_TERR));
}

int
sercngetc(dev)
	dev_t dev;
{
	u_char	stat, c;
	int	s;

	s = splserial();
	while (!ISSET(stat = MFP->mf_rsr, RSR_BFULL)) {
		if (!ISSET(stat, RSR_ENAB)) /* XXX */
			MFP->mf_rsr |= RSR_ENAB;
		if (stat & (RSR_FERR|RSR_PERR|RSR_OERR))
			c = MFP->mf_udr;
	}
	c = MFP->mf_udr;
	splx(s);
	return c;
}

u_int s_imra;
u_int s_stat1, s_stat2, s_stat3;
void
sercnputc(dev, c)
	dev_t dev;
	int c;
{
	int	timo;
	u_char	stat, imra;

	/* Mask serial interrupts */
	imra  = MFP->mf_imra & (IA_RRDY|IA_RERR|IA_TRDY|IA_TERR);
	single_inst_bclr_b(MFP->mf_imra, imra);
s_imra = imra;

	/* wait for any pending transmission to finish */
	timo = 50000;
s_stat1 = MFP->mf_tsr;
	while (!ISSET(stat = MFP->mf_tsr, TSR_BE) && --timo)
		;
	MFP->mf_udr = c;
	/* wait for this transmission to complete */
	timo = 1500000;
s_stat2 = MFP->mf_tsr;
	while (!ISSET(stat = MFP->mf_tsr, TSR_BE) && --timo)
		;

s_stat3 = MFP->mf_tsr;
	/* Clear pending serial interrupts and re-enable */
	single_inst_bclr_b(MFP->mf_ipra, imra);
	single_inst_bset_b(MFP->mf_imra, imra);
}

void
sercnpollc(dev, on)
	dev_t dev;
	int on;
{

}