1 files changed, 819 insertions, 0 deletions

diff --git a/sys/arch/vax/uba/dz.c b/sys/arch/vax/uba/dz.c
new file mode 100644
index 00000000000..f1636b7f3ef
--- /dev/null
+++ b/sys/arch/vax/uba/dz.c
@@ -0,0 +1,819 @@
+/*	$NetBSD: dz.c,v 1.1 1996/04/08 17:22:20 ragge Exp $	*/
+/*
+ * Copyright (c) 1996  Ken C. Wellsch.  All rights reserved.
+ * Copyright (c) 1992, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Ralph Campbell and Rick Macklem.
+ *
+ * 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 University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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/tty.h>
+#include <sys/proc.h>
+#include <sys/map.h>
+#include <sys/buf.h>
+#include <sys/conf.h>
+#include <sys/file.h>
+#include <sys/uio.h>
+#include <sys/kernel.h>
+#include <sys/syslog.h>
+#include <sys/device.h>
+
+#include <machine/pte.h>
+#include <machine/trap.h>
+
+#include <vax/uba/ubareg.h>
+#include <vax/uba/ubavar.h>
+
+#include <vax/uba/dzreg.h>
+
+/* A DZ-11 has 8 ports while a DZV/DZQ-11 has only 4. We use 8 by default */
+
+#define	NDZLINE 	8
+
+#define DZ_C2I(c)	((c)<<3)	/* convert controller # to index */
+#define DZ_I2C(c)	((c)>>3)	/* convert minor to controller # */
+#define DZ_PORT(u)	((u)&07)	/* extract the port # */
+
+struct	dz_softc {
+	struct	device	sc_dev;		/* Autoconf blaha */
+	dzregs *	sc_addr;	/* controller reg address */
+	int		sc_type;	/* DZ11 or DZV11? */
+	int		sc_rxint;	/* Receive interrupt count XXX */
+	u_char		sc_brk;		/* Break asserted on some lines */
+	struct {
+		struct	tty *	dz_tty;		/* what we work on */
+		caddr_t		dz_mem;		/* pointers to clist output */
+		caddr_t		dz_end;		/*   allowing pdma action */
+	} sc_dz[NDZLINE];
+};
+
+/* Flags used to monitor modem bits, make them understood outside driver */
+
+#define DML_DTR		TIOCM_DTR
+#define DML_DCD		TIOCM_CD
+#define DML_RI		TIOCM_RI
+#define DML_BRK		0100000		/* no equivalent, we will mask */
+
+static struct speedtab dzspeedtab[] =
+{
+  {       0,	0		},
+  {      50,	DZ_LPR_B50	},
+  {      75,	DZ_LPR_B75	},
+  {     110,	DZ_LPR_B110	},
+  {     134,	DZ_LPR_B134	},
+  {     150,	DZ_LPR_B150	},
+  {     300,	DZ_LPR_B300	},
+  {     600,	DZ_LPR_B600	},
+  {    1200,	DZ_LPR_B1200	},
+  {    1800,	DZ_LPR_B1800	},
+  {    2000,	DZ_LPR_B2000	},
+  {    2400,	DZ_LPR_B2400	},
+  {    3600,	DZ_LPR_B3600	},
+  {    4800,	DZ_LPR_B4800	},
+  {    7200,	DZ_LPR_B7200	},
+  {    9600,	DZ_LPR_B9600	},
+  {      -1,	-1		}
+};
+
+static	int	dz_match __P((struct device *, void *, void *));
+static	void	dz_attach __P((struct device *, struct device *, void *));
+static	void	dzrint __P((int));
+static	void	dzxint __P((int));
+static	void	dzstart __P((struct tty *));
+static	int	dzparam __P((struct tty *, struct termios *));
+static unsigned	dzmctl __P((struct dz_softc *, int, int, int));
+static	void	dzscan __P((void *));
+struct	tty *	dztty __P((dev_t));
+	int	dzopen __P((dev_t, int, int, struct proc *));
+	int	dzclose __P((dev_t, int, int, struct proc *));
+	int	dzread __P((dev_t, struct uio *, int));
+	int	dzwrite __P((dev_t, struct uio *, int));
+	int	dzioctl __P((dev_t, int, caddr_t, int, struct proc *));
+	int	dzstop __P((struct tty *, int));
+
+struct	cfdriver dz_cd = {
+	NULL, "dz", DV_TTY
+};
+
+struct	cfattach dz_ca = {
+	sizeof(struct dz_softc), dz_match, dz_attach
+};
+
+
+/*
+ * The DZ series doesn't interrupt on carrier transitions,
+ * so we have to use a timer to watch it.
+ */
+static int	dz_timer = 0;	/* true if timer started */
+
+#define DZ_DZ	8		/* Unibus DZ-11 board linecount */
+#define DZ_DZV	4		/* Q-bus DZV-11 or DZQ-11 */
+
+/* Autoconfig handles: setup the controller to interrupt, */
+/* then complete the housecleaning for full operation */
+
+static int
+dz_match (parent, match, aux)
+        struct device *parent;
+        void *match, *aux;
+{
+	struct uba_attach_args *ua = aux;
+	register dzregs *dzaddr;
+	register int n;
+
+	dzaddr = (dzregs *) ua->ua_addr;
+
+	/* Reset controller to initialize, enable TX interrupts */
+	/* to catch floating vector info elsewhere when completed */
+
+	dzaddr->dz_csr = (DZ_CSR_MSE | DZ_CSR_TXIE);
+	dzaddr->dz_tcr = 1;	/* Force a TX interrupt */
+
+	DELAY(100000);	/* delay 1/10 second */
+
+	dzaddr->dz_csr = DZ_CSR_RESET;
+
+	/* Now wait up to 3 seconds for reset/clear to complete. */
+
+	for (n = 0; n < 300; n++) {
+		DELAY(10000);
+		if ((dzaddr->dz_csr & DZ_CSR_RESET) == 0)
+			break;
+	}
+
+	/* If the RESET did not clear after 3 seconds, */
+	/* the controller must be broken. */
+
+	if (n >= 300)
+		return (0);
+
+	/* Register the TX interrupt handler */
+
+	ua->ua_ivec = dzxint;
+
+       	return (1);
+}
+
+static void
+dz_attach (parent, self, aux)
+        struct device *parent, *self;
+        void *aux;
+{
+	struct uba_softc *uh = (void *)parent;
+	struct	dz_softc *sc = (void *)self;
+	register struct uba_attach_args *ua = aux;
+	register dzregs *dzaddr;
+	register int n;
+
+	dzaddr = (dzregs *) ua->ua_addr;
+	sc->sc_addr = dzaddr;
+
+#ifdef QBA
+	if (uh->uh_type == QBA)
+		sc->sc_type = DZ_DZV;
+	else
+#endif
+		sc->sc_type = DZ_DZ;
+
+	sc->sc_rxint = sc->sc_brk = 0;
+
+	dzaddr->dz_csr = (DZ_CSR_MSE | DZ_CSR_RXIE | DZ_CSR_TXIE);
+	dzaddr->dz_dtr = 0;	/* Make sure DTR bits are zero */
+	dzaddr->dz_break = 0;	/* Status of BREAK bits, all off */
+
+	/* Initialize our softc structure. Should be done in open? */
+
+	for (n = 0; n < sc->sc_type; n++)
+		sc->sc_dz[n].dz_tty = ttymalloc();
+
+	/* Now register the RX interrupt handler */
+	ubasetvec(self, ua->ua_cvec-1, dzrint);
+
+	/* Alas no interrupt on modem bit changes, so we manually scan */
+
+	if (dz_timer == 0) {
+		dz_timer = 1;
+		timeout(dzscan, (void *)0, hz);
+	}
+
+	printf("\n");
+	return;
+}
+
+/* Receiver Interrupt */
+
+static void
+dzrint(cntlr)
+	int cntlr;
+{
+	struct	dz_softc *sc = dz_cd.cd_devs[cntlr];
+	volatile dzregs *dzaddr;
+	register struct tty *tp;
+	register int cc, line;
+	register unsigned c;
+	int overrun = 0;
+
+	sc->sc_rxint++;
+
+	dzaddr = sc->sc_addr;
+
+	while ((c = dzaddr->dz_rbuf) & DZ_RBUF_DATA_VALID) {
+		cc = c & 0xFF;
+		line = DZ_PORT(c>>8);
+		tp = sc->sc_dz[line].dz_tty;
+
+		if (!(tp->t_state & TS_ISOPEN)) {
+			wakeup((caddr_t)&tp->t_rawq);
+			continue;
+		}
+
+		if ((c & DZ_RBUF_OVERRUN_ERR) && overrun == 0) {
+			log(LOG_WARNING, "%s: silo overflow, line %d\n",
+			    sc->sc_dev.dv_xname, line);
+			overrun = 1;
+		}
+		/* A BREAK key will appear as a NULL with a framing error */
+		if (c & DZ_RBUF_FRAMING_ERR)
+			cc |= TTY_FE;
+		if (c & DZ_RBUF_PARITY_ERR)
+			cc |= TTY_PE;
+
+		(*linesw[tp->t_line].l_rint)(cc, tp);
+	}
+	return;
+}
+
+/* Transmitter Interrupt */
+
+static void
+dzxint(cntlr)
+	int cntlr;
+{
+	volatile dzregs *dzaddr;
+	register struct dz_softc *sc = dz_cd.cd_devs[cntlr];
+	register struct tty *tp;
+	register unsigned csr;
+	register int line;
+
+	dzaddr = sc->sc_addr;
+
+	/*
+	 * Switch to POLLED mode.
+	 *   Some simple measurements indicated that even on
+	 *  one port, by freeing the scanner in the controller
+	 *  by either providing a character or turning off
+	 *  the port when output is complete, the transmitter
+	 *  was ready to accept more output when polled again.
+	 *   With just two ports running the game "worms,"
+	 *  almost every interrupt serviced both transmitters!
+	 *   Each UART is double buffered, so if the scanner
+	 *  is quick enough and timing works out, we can even
+	 *  feed the same port twice.
+	 */
+
+	dzaddr->dz_csr &= ~(DZ_CSR_TXIE);
+
+	while (((csr = dzaddr->dz_csr) & DZ_CSR_TX_READY) != 0) {
+
+		line = DZ_PORT(csr>>8);
+
+		if (sc->sc_dz[line].dz_mem < sc->sc_dz[line].dz_end) {
+			dzaddr->dz_tbuf = *sc->sc_dz[line].dz_mem++; 
+			continue;
+		}
+
+		/*
+		 * Turn off this TX port as all pending output
+		 * has been completed - thus freeing the scanner
+		 * on the controller to hopefully find another
+		 * pending TX operation we can service now.
+		 * (avoiding the overhead of another interrupt)
+		 */
+
+		dzaddr->dz_tcr &= ~(1 << line);
+
+		tp = sc->sc_dz[line].dz_tty;
+
+		tp->t_state &= ~TS_BUSY;
+
+		if (tp->t_state & TS_FLUSH)
+			tp->t_state &= ~TS_FLUSH;
+		else {
+			ndflush (&tp->t_outq, (sc->sc_dz[line].dz_mem -
+					(caddr_t)tp->t_outq.c_cf));
+			sc->sc_dz[line].dz_end = sc->sc_dz[line].dz_mem =
+			    tp->t_outq.c_cf;
+		}
+
+		if (tp->t_line)
+			(*linesw[tp->t_line].l_start)(tp);
+		else
+			dzstart(tp);
+	}
+
+	/*
+	 * Re-enable TX interrupts.
+	 */
+
+	dzaddr->dz_csr |= (DZ_CSR_TXIE);
+	return;
+}
+
+int
+dzopen(dev, flag, mode, p)
+	dev_t dev;
+	int flag, mode;
+	struct proc *p;
+{
+	register struct tty *tp;
+	register int unit, line;
+	struct	dz_softc *sc;
+	int s, error = 0;
+
+	unit = DZ_I2C(minor(dev));
+	line = DZ_PORT(minor(dev));
+
+	if (unit >= dz_cd.cd_ndevs ||  dz_cd.cd_devs[unit] == NULL)
+		return (ENXIO);
+
+	sc = dz_cd.cd_devs[unit];
+
+	if (line >= sc->sc_type)
+		return ENXIO;
+
+	tp = sc->sc_dz[line].dz_tty;
+	if (tp == NULL)
+		return (ENODEV);
+	tp->t_oproc   = dzstart;
+	tp->t_param   = dzparam;
+	tp->t_dev = dev;
+	if ((tp->t_state & TS_ISOPEN) == 0) {
+		tp->t_state |= TS_WOPEN;
+		ttychars(tp);
+		if (tp->t_ispeed == 0) {
+			tp->t_iflag = TTYDEF_IFLAG;
+			tp->t_oflag = TTYDEF_OFLAG;
+			tp->t_cflag = TTYDEF_CFLAG;
+			tp->t_lflag = TTYDEF_LFLAG;
+			tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
+		}
+		(void) dzparam(tp, &tp->t_termios);
+		ttsetwater(tp);
+	} else if ((tp->t_state & TS_XCLUDE) && p->p_ucred->cr_uid != 0)
+		return (EBUSY);
+	/* Use DMBIS and *not* DMSET or else we clobber incoming bits */
+	if (dzmctl(sc, line, DML_DTR, DMBIS) & DML_DCD)
+		tp->t_state |= TS_CARR_ON;
+	s = spltty();
+	while (!(flag & O_NONBLOCK) && !(tp->t_cflag & CLOCAL) &&
+	       !(tp->t_state & TS_CARR_ON)) {
+		tp->t_state |= TS_WOPEN;
+		error = ttysleep(tp, (caddr_t)&tp->t_rawq,
+				TTIPRI | PCATCH, ttopen, 0);
+		if (error)
+			break;
+	}
+	(void) splx(s);
+	if (error)
+		return (error);
+	return ((*linesw[tp->t_line].l_open)(dev, tp));
+}
+
+/*ARGSUSED*/
+int
+dzclose (dev, flag, mode, p)
+	dev_t dev;
+	int flag, mode;
+	struct proc *p;
+{
+	struct	dz_softc *sc;
+	register struct tty *tp;
+	register int unit, line;
+
+	
+	unit = DZ_I2C(minor(dev));
+	line = DZ_PORT(minor(dev));
+	sc = dz_cd.cd_devs[unit];
+
+	tp = sc->sc_dz[line].dz_tty;
+
+	(*linesw[tp->t_line].l_close)(tp, flag);
+
+	/* Make sure a BREAK state is not left enabled. */
+	(void) dzmctl(sc, line, DML_BRK, DMBIC);
+
+	/* Do a hangup if so required. */
+	if ((tp->t_cflag & HUPCL) || (tp->t_state & TS_WOPEN) ||
+	    !(tp->t_state & TS_ISOPEN))
+		(void) dzmctl(sc, line, 0, DMSET);
+
+	return (ttyclose(tp));
+}
+
+int
+dzread (dev, uio, flag)
+	dev_t dev;
+	struct uio *uio;
+{
+	register struct tty *tp;
+	struct	dz_softc *sc;
+
+	sc = dz_cd.cd_devs[DZ_I2C(minor(dev))];
+
+	tp = sc->sc_dz[DZ_PORT(minor(dev))].dz_tty;
+	return ((*linesw[tp->t_line].l_read)(tp, uio, flag));
+}
+
+int
+dzwrite (dev, uio, flag)
+	dev_t dev;
+	struct uio *uio;
+{
+	register struct tty *tp;
+	struct	dz_softc *sc;
+
+	sc = dz_cd.cd_devs[DZ_I2C(minor(dev))];
+
+	tp = sc->sc_dz[DZ_PORT(minor(dev))].dz_tty;
+	return ((*linesw[tp->t_line].l_write)(tp, uio, flag));
+}
+
+/*ARGSUSED*/
+int
+dzioctl (dev, cmd, data, flag, p)
+	dev_t dev;
+	int cmd;
+	caddr_t data;
+	int flag;
+	struct proc *p;
+{
+	struct	dz_softc *sc;
+	register struct tty *tp;
+	register int unit, line;
+	int error;
+
+	unit = DZ_I2C(minor(dev));
+	line = DZ_PORT(minor(dev));
+	sc = dz_cd.cd_devs[unit];
+	tp = sc->sc_dz[line].dz_tty;
+
+	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:
+		(void) dzmctl(sc, line, DML_BRK, DMBIS);
+		break;
+
+	case TIOCCBRK:
+		(void) dzmctl(sc, line, DML_BRK, DMBIC);
+		break;
+
+	case TIOCSDTR:
+		(void) dzmctl(sc, line, DML_DTR, DMBIS);
+		break;
+
+	case TIOCCDTR:
+		(void) dzmctl(sc, line, DML_DTR, DMBIC);
+		break;
+
+	case TIOCMSET:
+		(void) dzmctl(sc, line, *(int *)data, DMSET);
+		break;
+
+	case TIOCMBIS:
+		(void) dzmctl(sc, line, *(int *)data, DMBIS);
+		break;
+
+	case TIOCMBIC:
+		(void) dzmctl(sc, line, *(int *)data, DMBIC);
+		break;
+
+	case TIOCMGET:
+		*(int *)data = (dzmctl(sc, line, 0, DMGET) & ~DML_BRK);
+		break;
+
+	default:
+		return (ENOTTY);
+	}
+	return (0);
+}
+
+struct tty *
+dztty (dev)
+        dev_t dev;
+{
+	struct	dz_softc *sc = dz_cd.cd_devs[DZ_I2C(minor(dev))];
+        struct tty *tp = sc->sc_dz[DZ_PORT(minor(dev))].dz_tty;
+
+        return (tp);
+}
+
+/*ARGSUSED*/
+int
+dzstop (tp, flag)
+	register struct tty *tp;
+{
+	register struct dz_softc *sc;
+	int unit, line, s;
+
+	unit = DZ_I2C(minor(tp->t_dev));
+	line = DZ_PORT(minor(tp->t_dev));
+	sc = dz_cd.cd_devs[unit];
+
+	s = spltty();
+
+	if (tp->t_state & TS_BUSY)
+	{
+		sc->sc_dz[line].dz_end = sc->sc_dz[line].dz_mem;
+		if (!(tp->t_state & TS_TTSTOP))
+			tp->t_state |= TS_FLUSH;
+	}
+	(void) splx(s);
+	return 0;
+}
+
+static void
+dzstart (tp)
+	register struct tty *tp;
+{
+	register struct dz_softc *sc;
+	register dzregs *dzaddr;
+	register int unit, line;
+	register int cc;
+	int s;
+
+	unit = DZ_I2C(minor(tp->t_dev));
+	line = DZ_PORT(minor(tp->t_dev));
+	sc = dz_cd.cd_devs[unit];
+
+	s = spltty();
+	if (tp->t_state & (TS_TIMEOUT|TS_BUSY|TS_TTSTOP))
+		goto out;
+	if (tp->t_outq.c_cc <= tp->t_lowat) {
+		if (tp->t_state & TS_ASLEEP) {
+			tp->t_state &= ~TS_ASLEEP;
+			wakeup((caddr_t)&tp->t_outq);
+		}
+		selwakeup(&tp->t_wsel);
+	}
+	if (tp->t_outq.c_cc == 0)
+		goto out;
+	cc = ndqb(&tp->t_outq, 0);
+	if (cc == 0) 
+		goto out;
+
+	tp->t_state |= TS_BUSY;
+
+	dzaddr = sc->sc_addr;
+
+	sc->sc_dz[line].dz_end = sc->sc_dz[line].dz_mem = tp->t_outq.c_cf;
+	sc->sc_dz[line].dz_end += cc;
+	dzaddr->dz_tcr |= (1 << line);	/* Enable this TX port */
+
+out:
+	(void) splx(s);
+	return;
+}
+
+static int
+dzparam(tp, t)
+	register struct tty *tp;
+	register struct termios *t;
+{
+	struct	dz_softc *sc;
+	register dzregs *dzaddr;
+	register int cflag = t->c_cflag;
+	int unit, line;
+	int ispeed = ttspeedtab(t->c_ispeed, dzspeedtab);
+	int ospeed = ttspeedtab(t->c_ospeed, dzspeedtab);
+	register unsigned lpr;
+	int s;
+
+	unit = DZ_I2C(minor(tp->t_dev));
+	line = DZ_PORT(minor(tp->t_dev));
+	sc = dz_cd.cd_devs[unit];
+
+	/* check requested parameters */
+        if (ospeed < 0 || ispeed < 0 || ispeed != ospeed)
+                return (EINVAL);
+
+        tp->t_ispeed = t->c_ispeed;
+        tp->t_ospeed = t->c_ospeed;
+        tp->t_cflag = cflag;
+
+	if (ospeed == 0) {
+		(void) dzmctl(sc, line, 0, DMSET);	/* hang up line */
+		return (0);
+	}
+
+	s = spltty();
+	dzaddr = sc->sc_addr;
+
+	lpr = DZ_LPR_RX_ENABLE | ((ispeed&0xF)<<8) | line;
+
+	switch (cflag & CSIZE)
+	{
+	  case CS5:
+		lpr |= DZ_LPR_5_BIT_CHAR;
+		break;
+	  case CS6:
+		lpr |= DZ_LPR_6_BIT_CHAR;
+		break;
+	  case CS7:
+		lpr |= DZ_LPR_7_BIT_CHAR;
+		break;
+	  default:
+		lpr |= DZ_LPR_8_BIT_CHAR;
+		break;
+	}
+	if (cflag & PARENB)
+		lpr |= DZ_LPR_PARENB;
+	if (cflag & PARODD)
+		lpr |= DZ_LPR_OPAR;
+	if (cflag & CSTOPB)
+		lpr |= DZ_LPR_2_STOP;
+
+	dzaddr->dz_lpr = lpr;
+
+	(void) splx(s);
+	return (0);
+}
+
+static unsigned
+dzmctl(sc, line, bits, how)
+	register struct dz_softc *sc;
+	int line, bits, how;
+{
+	register dzregs *dzaddr;
+	register unsigned status;
+	register unsigned mbits;
+	register unsigned bit;
+	int s;
+
+	s = spltty();
+
+	dzaddr = sc->sc_addr;
+
+	mbits = 0;
+
+	bit = (1 << line);
+
+	/* external signals as seen from the port */
+
+	status = dzaddr->dz_dcd;
+
+	if (status & bit)
+		mbits |= DML_DCD;
+
+	status = dzaddr->dz_ring;
+
+	if (status & bit)
+		mbits |= DML_RI;
+
+	/* internal signals/state delivered to port */
+
+	status = dzaddr->dz_dtr;
+
+	if (status & bit)
+		mbits |= DML_DTR;
+
+	if (sc->sc_brk & bit)
+		mbits |= DML_BRK;
+
+	switch (how)
+	{
+	  case DMSET:
+		mbits = bits;
+		break;
+
+	  case DMBIS:
+		mbits |= bits;
+		break;
+
+	  case DMBIC:
+		mbits &= ~bits;
+		break;
+
+	  case DMGET:
+		(void) splx(s);
+		return (mbits);
+	}
+
+	if (mbits & DML_DTR)
+		dzaddr->dz_dtr |= bit;
+	else
+		dzaddr->dz_dtr &= ~bit;
+
+	if (mbits & DML_BRK)
+		dzaddr->dz_break = (sc->sc_brk |= bit);
+	else
+		dzaddr->dz_break = (sc->sc_brk &= ~bit);
+
+	(void) splx(s);
+	return (mbits);
+}
+
+/*
+ * This is called by timeout() periodically.
+ * Check to see if modem status bits have changed.
+ */
+static void
+dzscan(arg)
+	void *arg;
+{
+	register dzregs *dzaddr;
+	register struct dz_softc *sc;
+	register struct tty *tp;
+	register int n, bit, port;
+	unsigned csr;
+	int s;
+
+	s = spltty();
+
+	for (n = 0; n < dz_cd.cd_ndevs; n++) {
+
+		if (dz_cd.cd_devs[n] == NULL)
+			continue;
+
+		sc = dz_cd.cd_devs[n];
+
+		for (port = 0; port < sc->sc_type; port++) {
+
+			dzaddr = sc->sc_addr;
+			tp = sc->sc_dz[port].dz_tty;
+			bit = (1 << port);
+	
+			if (dzaddr->dz_dcd & bit) { /* carrier present */
+
+				if (!(tp->t_state & TS_CARR_ON))
+					(void)(*linesw[tp->t_line].l_modem)
+					    (tp, 1);
+			} else if ((tp->t_state & TS_CARR_ON) &&
+				(*linesw[tp->t_line].l_modem)(tp, 0) == 0)
+				    dzaddr->dz_tcr &= ~bit;
+	    	}
+
+		/*
+		 *  If the RX interrupt rate is this high, switch
+		 *  the controller to Silo Alarm - which means don't
+	 	 *  interrupt until the RX silo has 16 characters in
+	 	 *  it (the silo is 64 characters in all).
+		 *  Avoid oscillating SA on and off by not turning
+		 *  if off unless the rate is appropriately low.
+		 */
+
+		dzaddr = sc->sc_addr;
+
+		csr = dzaddr->dz_csr;
+
+		if (sc->sc_rxint > (16*10)) {
+			if ((csr & DZ_CSR_SAE) == 0)
+				dzaddr->dz_csr = (csr | DZ_CSR_SAE);
+	    	} else if ((csr & DZ_CSR_SAE) != 0)
+			if (sc->sc_rxint < 10)
+				dzaddr->dz_csr = (csr & ~(DZ_CSR_SAE));
+
+		sc->sc_rxint = 0;
+	}
+	(void) splx(s);
+	timeout(dzscan, (void *)0, hz);
+	return;
+}