src/sys/dev/ic/cy.c

/*	$OpenBSD: cy.c,v 1.42 2023/09/11 08:41:26 mvs Exp $	*/
/*
 * Copyright (c) 1996 Timo Rossi.
 * 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. Neither the name of the author nor the names of contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

/*
 * cy.c
 *
 * Driver for Cyclades Cyclom-8/16/32 multiport serial cards
 * (currently not tested with Cyclom-32 cards)
 *
 * Timo Rossi, 1996
 *
 * Supports both ISA and PCI Cyclom cards
 *
 * Uses CD1400 automatic CTS flow control, and
 * if CY_HW_RTS is defined, uses CD1400 automatic input flow control.
 * This requires a special cable that exchanges the RTS and DTR lines.
 *
 * Lots of debug output can be enabled by defining CY_DEBUG
 * Some debugging counters (number of receive/transmit interrupts etc.)
 * can be enabled by defining CY_DEBUG1
 *
 * This version uses the bus_space/io_??() stuff
 *
 */

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/syslog.h>
#include <sys/fcntl.h>
#include <sys/tty.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/malloc.h>
#include <sys/systm.h>

#include <machine/bus.h>
#include <machine/intr.h>

#include <dev/ic/cd1400reg.h>
#include <dev/ic/cyreg.h>


int	cy_intr(void *);
int	cyparam(struct tty *, struct termios *);
void	cystart(struct tty *);
void	cy_poll(void *);
int	cy_modem_control(struct cy_port *, int, int);
void	cy_enable_transmitter(struct cy_port *);
void	cd1400_channel_cmd(struct cy_port *, int);
int	cy_speed(speed_t, int *, int *, int);

struct cfdriver cy_cd = {
	NULL, "cy", DV_TTY
};

/*
 * Common probe routine
 *
 * returns the number of chips found.
 */
int
cy_probe_common(bus_space_tag_t memt, bus_space_handle_t memh, int bustype)
{
	int cy_chip, chip_offs;
	u_char firmware_ver;
	int nchips;

	/* Cyclom card hardware reset */
	bus_space_write_1(memt, memh, CY16_RESET<<bustype, 0);
	DELAY(500); /* wait for reset to complete */
	bus_space_write_1(memt, memh, CY_CLEAR_INTR<<bustype, 0);

#ifdef CY_DEBUG
	printf("cy: card reset done\n");
#endif

	nchips = 0;

	for (cy_chip = 0, chip_offs = 0;
	    cy_chip < CY_MAX_CD1400s;
	    cy_chip++, chip_offs += (CY_CD1400_MEMSPACING << bustype)) {
		int i;

		/* the last 4 cd1400s are 'interleaved'
		   with the first 4 on 32-port boards */
		if (cy_chip == 4)
			chip_offs -= (CY32_ADDR_FIX << bustype);

#ifdef CY_DEBUG
		printf("cy: probe chip %d offset 0x%x ... ",
		    cy_chip, chip_offs);
#endif

		/* wait until the chip is ready for command */
		DELAY(1000);
		if (bus_space_read_1(memt, memh, chip_offs +
		    ((CD1400_CCR << 1) << bustype)) != 0) {
#ifdef CY_DEBUG
			printf("not ready for command\n");
#endif
			break;
		}

		/* clear the firmware version reg. */
		bus_space_write_1(memt, memh, chip_offs +
		    ((CD1400_GFRCR << 1) << bustype), 0);

		/*
		 * On Cyclom-16 references to non-existent chip 4
		 * actually access chip 0 (address line 9 not decoded).
		 * Here we check if the clearing of chip 4 GFRCR actually
		 * cleared chip 0 GFRCR. In that case we have a 16 port card.
		 */
		if (cy_chip == 4 &&
		    bus_space_read_1(memt, memh, chip_offs +
			((CD1400_GFRCR << 1) << bustype)) == 0)
			break;

		/* reset the chip */
		bus_space_write_1(memt, memh, chip_offs +
		    ((CD1400_CCR << 1) << bustype),
		    CD1400_CCR_CMDRESET | CD1400_CCR_FULLRESET);

		/* wait for the chip to initialize itself */
		for (i = 0; i < 200; i++) {
			DELAY(50);
			firmware_ver = bus_space_read_1(memt, memh, chip_offs +
			    ((CD1400_GFRCR << 1) << bustype));
			if ((firmware_ver & 0xf0) == 0x40) /* found a CD1400 */
				break;
		}
#ifdef CY_DEBUG
		printf("firmware version 0x%x\n", firmware_ver);
#endif

		if ((firmware_ver & 0xf0) != 0x40)
			break;

		/* firmware version OK, CD1400 found */
		nchips++;
	}

	if (nchips == 0) {
#ifdef CY_DEBUG
		printf("no CD1400s found\n");
#endif
		return (0);
	}

#ifdef CY_DEBUG
	printf("found %d CD1400s\n", nchips);
#endif

	return (nchips);
}

void
cy_attach(struct device *parent, struct device *self)
{
	int card, port, cy_chip, num_chips, cdu, chip_offs, cy_clock;
	struct cy_softc *sc = (void *)self;

	card = sc->sc_dev.dv_unit;
	num_chips = sc->sc_nr_cd1400s;
	if (num_chips == 0)
		return;

	timeout_set(&sc->sc_poll_to, cy_poll, sc);
	bzero(sc->sc_ports, sizeof(sc->sc_ports));
	sc->sc_nports = num_chips * CD1400_NO_OF_CHANNELS;

	port = 0;
	for (cy_chip = 0, chip_offs = 0;
	    cy_chip < num_chips;
	    cy_chip++, chip_offs += (CY_CD1400_MEMSPACING<<sc->sc_bustype)) {
		if (cy_chip == 4)
			chip_offs -= (CY32_ADDR_FIX<<sc->sc_bustype);

#ifdef CY_DEBUG
		printf("attach CD1400 #%d offset 0x%x\n", cy_chip, chip_offs);
#endif
		sc->sc_cd1400_offs[cy_chip] = chip_offs;

		/* configure port 0 as serial port
		   (should already be after reset) */
		cd_write_reg_sc(sc, cy_chip, CD1400_GCR, 0);

		/* Set cy_clock depending on firmware version */
		if (cd_read_reg_sc(sc, cy_chip, CD1400_GFRCR) <= 0x46)
			cy_clock = CY_CLOCK;
		else
			cy_clock = CY_CLOCK_60;

		/* set up a receive timeout period (1ms) */
		cd_write_reg_sc(sc, cy_chip, CD1400_PPR,
		    (cy_clock / CD1400_PPR_PRESCALER / 1000) + 1);

		for (cdu = 0; cdu < CD1400_NO_OF_CHANNELS; cdu++) {
			sc->sc_ports[port].cy_port_num = port;
			sc->sc_ports[port].cy_memt = sc->sc_memt;
			sc->sc_ports[port].cy_memh = sc->sc_memh;
			sc->sc_ports[port].cy_chip_offs = chip_offs;
			sc->sc_ports[port].cy_bustype = sc->sc_bustype;
			sc->sc_ports[port].cy_clock = cy_clock;

			/* should we initialize anything else here? */
			port++;
		} /* for(each port on one CD1400...) */

	} /* for(each CD1400 on a card... ) */

	printf(": %d ports\n", port);

	/* ensure an edge for the next interrupt */
	bus_space_write_1(sc->sc_memt, sc->sc_memh,
	    CY_CLEAR_INTR<<sc->sc_bustype, 0);
}

/*
 * open routine. returns zero if successful, else error code
 */
int cyopen(dev_t, int, int, struct proc *);
int cyclose(dev_t, int, int, struct proc *);
int cyread(dev_t, struct uio *, int);
int cywrite(dev_t, struct uio *, int);
struct tty *cytty(dev_t);
int cyioctl(dev_t, u_long, caddr_t, int, struct proc *);
int cystop(struct tty *, int flag);

int
cyopen(dev_t dev, int flag, int mode, struct proc *p)
{
	int card = CY_CARD(dev);
	int port = CY_PORT(dev);
	struct cy_softc *sc;
	struct cy_port *cy;
	struct tty *tp;
	int s, error;

	if (card >= cy_cd.cd_ndevs ||
	    (sc = cy_cd.cd_devs[card]) == NULL) {
		return (ENXIO);
	}

#ifdef CY_DEBUG
	printf("%s open port %d flag 0x%x mode 0x%x\n", sc->sc_dev.dv_xname,
	    port, flag, mode);
#endif

	cy = &sc->sc_ports[port];

	s = spltty();
	if (cy->cy_tty == NULL) {
		cy->cy_tty = ttymalloc(0);
	}
	splx(s);

	tp = cy->cy_tty;
	tp->t_oproc = cystart;
	tp->t_param = cyparam;
	tp->t_dev = dev;

	if (!ISSET(tp->t_state, TS_ISOPEN)) {
		SET(tp->t_state, TS_WOPEN);
		ttychars(tp);
		tp->t_iflag = TTYDEF_IFLAG;
		tp->t_oflag = TTYDEF_OFLAG;
		tp->t_cflag = TTYDEF_CFLAG;
		if (ISSET(cy->cy_openflags, TIOCFLAG_CLOCAL))
			SET(tp->t_cflag, CLOCAL);
		if (ISSET(cy->cy_openflags, TIOCFLAG_CRTSCTS))
			SET(tp->t_cflag, CRTSCTS);
		if (ISSET(cy->cy_openflags, TIOCFLAG_MDMBUF))
			SET(tp->t_cflag, MDMBUF);
		tp->t_lflag = TTYDEF_LFLAG;
		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;

		s = spltty();

		/*
		 * Allocate input ring buffer if we don't already have one
		 */
		if (cy->cy_ibuf == NULL) {
			cy->cy_ibuf = malloc(IBUF_SIZE, M_DEVBUF, M_NOWAIT);
			if (cy->cy_ibuf == NULL) {
				printf("%s: (port %d) can't allocate input buffer\n",
				       sc->sc_dev.dv_xname, port);
				splx(s);
				return (ENOMEM);
			}
			cy->cy_ibuf_end = cy->cy_ibuf + IBUF_SIZE;
		}

		/* mark the ring buffer as empty */
		cy->cy_ibuf_rd_ptr = cy->cy_ibuf_wr_ptr = cy->cy_ibuf;

		/* select CD1400 channel */
		cd_write_reg(cy, CD1400_CAR, port & CD1400_CAR_CHAN);
		/* reset the channel */
		cd1400_channel_cmd(cy, CD1400_CCR_CMDRESET);
		/* encode unit (port) number in LIVR */
		/* there is just enough space for 5 bits (32 ports) */
		cd_write_reg(cy, CD1400_LIVR, port << 3);

		cy->cy_channel_control = 0;

		if (!timeout_pending(&sc->sc_poll_to))
			timeout_add(&sc->sc_poll_to, 1);

		/* this sets parameters and raises DTR */
		cyparam(tp, &tp->t_termios);

		ttsetwater(tp);

		/* raise RTS too */
		cy_modem_control(cy, TIOCM_RTS, DMBIS);

		cy->cy_carrier_stat = cd_read_reg(cy, CD1400_MSVR2);

		/* enable receiver and modem change interrupts */
		cd_write_reg(cy, CD1400_SRER,
		    CD1400_SRER_MDMCH | CD1400_SRER_RXDATA);

		if (CY_DIALOUT(dev) ||
		    ISSET(cy->cy_openflags, TIOCFLAG_SOFTCAR) ||
		    ISSET(tp->t_cflag, MDMBUF) ||
		    ISSET(cy->cy_carrier_stat, CD1400_MSVR2_CD))
			SET(tp->t_state, TS_CARR_ON);
		else
			CLR(tp->t_state, TS_CARR_ON);
	} else if (ISSET(tp->t_state, TS_XCLUDE) && suser(p) != 0) {
		return (EBUSY);
	} else {
		s = spltty();
	}

	/* wait for carrier if necessary */
	if (!ISSET(flag, O_NONBLOCK)) {
		while (!ISSET(tp->t_cflag, CLOCAL) &&
		    !ISSET(tp->t_state, TS_CARR_ON)) {
			SET(tp->t_state, TS_WOPEN);
			error = ttysleep(tp, &tp->t_rawq, TTIPRI | PCATCH,
			    ttopen);
			if (error != 0) {
				splx(s);
				CLR(tp->t_state, TS_WOPEN);
				return (error);
			}
		}
	}

	splx(s);

	return (*linesw[tp->t_line].l_open)(dev, tp, p);
}

/*
 * close routine. returns zero if successful, else error code
 */
int
cyclose(dev_t dev, int flag, int mode, struct proc *p)
{
	int card = CY_CARD(dev);
	int port = CY_PORT(dev);
	struct cy_softc *sc = cy_cd.cd_devs[card];
	struct cy_port *cy = &sc->sc_ports[port];
	struct tty *tp = cy->cy_tty;
	int s;

#ifdef CY_DEBUG
	printf("%s close port %d, flag 0x%x, mode 0x%x\n", sc->sc_dev.dv_xname,
	    port, flag, mode);
#endif

	(*linesw[tp->t_line].l_close)(tp, flag, p);
	s = spltty();

	if (ISSET(tp->t_cflag, HUPCL) &&
	    !ISSET(cy->cy_openflags, TIOCFLAG_SOFTCAR)) {
		/* drop DTR and RTS
		   (should we wait for output buffer to become empty first?) */
		cy_modem_control(cy, 0, DMSET);
	}

	/*
	 * XXX should we disable modem change and
	 * receive interrupts here or somewhere ?
	 */
	CLR(tp->t_state, TS_BUSY | TS_FLUSH);

	splx(s);
	ttyclose(tp);

	return (0);
}

/*
 * Read routine
 */
int
cyread(dev_t dev, struct uio *uio, int flag)
{
	int card = CY_CARD(dev);
	int port = CY_PORT(dev);
	struct cy_softc *sc = cy_cd.cd_devs[card];
	struct cy_port *cy = &sc->sc_ports[port];
	struct tty *tp = cy->cy_tty;

#ifdef CY_DEBUG
	printf("%s read port %d uio %p flag 0x%x\n", sc->sc_dev.dv_xname,
	    port, uio, flag);
#endif

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

/*
 * Write routine
 */
int
cywrite(dev_t dev, struct uio *uio, int flag)
{
	int card = CY_CARD(dev);
	int port = CY_PORT(dev);
	struct cy_softc *sc = cy_cd.cd_devs[card];
	struct cy_port *cy = &sc->sc_ports[port];
	struct tty *tp = cy->cy_tty;

#ifdef CY_DEBUG
	printf("%s write port %d uio %p flag 0x%x\n", sc->sc_dev.dv_xname,
	    port, uio, flag);
#endif

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

/*
 * return tty pointer
 */
struct tty *
cytty(dev_t dev)
{
	int card = CY_CARD(dev);
	int port = CY_PORT(dev);
	struct cy_softc *sc = cy_cd.cd_devs[card];
	struct cy_port *cy = &sc->sc_ports[port];
	struct tty *tp = cy->cy_tty;

	return (tp);
}

/*
 * ioctl routine
 */
int
cyioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
{
	int card = CY_CARD(dev);
	int port = CY_PORT(dev);
	struct cy_softc *sc = cy_cd.cd_devs[card];
	struct cy_port *cy = &sc->sc_ports[port];
	struct tty *tp = cy->cy_tty;
	int error;

#ifdef CY_DEBUG
	printf("%s port %d ioctl cmd 0x%lx data %p flag 0x%x\n",
	    sc->sc_dev.dv_xname, port, cmd, data, flag);
#endif

	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);

	/* XXX should not allow dropping DTR when dialin? */

	switch (cmd) {
	case TIOCSBRK:		/* start break */
		SET(cy->cy_flags, CYF_START_BREAK);
		cy_enable_transmitter(cy);
		break;

	case TIOCCBRK:		/* stop break */
		SET(cy->cy_flags, CYF_END_BREAK);
		cy_enable_transmitter(cy);
		break;

	case TIOCSDTR:		/* DTR on */
		cy_modem_control(cy, TIOCM_DTR, DMBIS);
		break;

	case TIOCCDTR:		/* DTR off */
		cy_modem_control(cy, TIOCM_DTR, DMBIC);
		break;

	case TIOCMSET:		/* set new modem control line values */
		cy_modem_control(cy, *((int *)data), DMSET);
		break;

	case TIOCMBIS:		/* turn modem control bits on */
		cy_modem_control(cy, *((int *)data), DMBIS);
		break;

	case TIOCMBIC:		/* turn modem control bits off */
		cy_modem_control(cy, *((int *)data), DMBIC);
		break;

	case TIOCMGET:		/* get modem control/status line state */
		*((int *)data) = cy_modem_control(cy, 0, DMGET);
		break;

	case TIOCGFLAGS:
		*((int *)data) = cy->cy_openflags |
		    (CY_DIALOUT(dev) ? TIOCFLAG_SOFTCAR : 0);
		break;

	case TIOCSFLAGS:
		error = suser(p);
		if (error != 0)
			return (EPERM);

		cy->cy_openflags = *((int *)data) &
		    (TIOCFLAG_SOFTCAR | TIOCFLAG_CLOCAL |
		     TIOCFLAG_CRTSCTS | TIOCFLAG_MDMBUF);
		break;

	default:
		return (ENOTTY);
	}

	return (0);
}

/*
 * start output
 */
void
cystart(struct tty *tp)
{
	int card = CY_CARD(tp->t_dev);
	int port = CY_PORT(tp->t_dev);
	struct cy_softc *sc = cy_cd.cd_devs[card];
	struct cy_port *cy = &sc->sc_ports[port];
	int s;

#ifdef CY_DEBUG
	printf("%s port %d start, tty %p\n", sc->sc_dev.dv_xname, port, tp);
#endif

	s = spltty();

#ifdef CY_DEBUG1
	cy->cy_start_count++;
#endif

	if (!ISSET(tp->t_state, TS_TTSTOP | TS_TIMEOUT | TS_BUSY)) {
		ttwakeupwr(tp);
		if (tp->t_outq.c_cc == 0)
			goto out;

		SET(tp->t_state, TS_BUSY);
		cy_enable_transmitter(cy);
	}
out:

	splx(s);
}

/*
 * stop output
 */
int
cystop(struct tty *tp, int flag)
{
	int card = CY_CARD(tp->t_dev);
	int port = CY_PORT(tp->t_dev);
	struct cy_softc *sc = cy_cd.cd_devs[card];
	struct cy_port *cy = &sc->sc_ports[port];
	int s;

#ifdef CY_DEBUG
	printf("%s port %d stop tty %p flag 0x%x\n", sc->sc_dev.dv_xname,
	    port, tp, flag);
#endif

	s = spltty();

	if (ISSET(tp->t_state, TS_BUSY)) {
		if (!ISSET(tp->t_state, TS_TTSTOP))
			SET(tp->t_state, TS_FLUSH);

		/*
		 * the transmit interrupt routine will disable transmit when it
		 * notices that CYF_STOP has been set.
		 */
		SET(cy->cy_flags, CYF_STOP);
	}
	splx(s);
	return (0);
}

/*
 * parameter setting routine.
 * returns 0 if successful, else returns error code
 */
int
cyparam(struct tty *tp, struct termios *t)
{
	int card = CY_CARD(tp->t_dev);
	int port = CY_PORT(tp->t_dev);
	struct cy_softc *sc = cy_cd.cd_devs[card];
	struct cy_port *cy = &sc->sc_ports[port];
	int ibpr, obpr, i_clk_opt, o_clk_opt;
	int s, opt;

#ifdef CY_DEBUG
	printf("%s port %d param tty %p termios %p\n", sc->sc_dev.dv_xname,
	    port, tp, t);
	printf("ispeed %d ospeed %d\n", t->c_ispeed, t->c_ospeed);
#endif

	if (t->c_ospeed != 0 &&
	    cy_speed(t->c_ospeed, &o_clk_opt, &obpr, cy->cy_clock) < 0)
		return (EINVAL);

	if (t->c_ispeed != 0 &&
	    cy_speed(t->c_ispeed, &i_clk_opt, &ibpr, cy->cy_clock) < 0)
		return (EINVAL);

	s = spltty();

	/* hang up the line is ospeed is zero, else turn DTR on */
	cy_modem_control(cy, TIOCM_DTR, (t->c_ospeed == 0 ? DMBIC : DMBIS));

	/* channel was selected by the above call to cy_modem_control() */
	/* cd_write_reg(cy, CD1400_CAR, port & CD1400_CAR_CHAN); */

	/* set transmit speed */
	if (t->c_ospeed != 0) {
		cd_write_reg(cy, CD1400_TCOR, o_clk_opt);
		cd_write_reg(cy, CD1400_TBPR, obpr);
	}
	/* set receive speed */
	if (t->c_ispeed != 0) {
		cd_write_reg(cy, CD1400_RCOR, i_clk_opt);
		cd_write_reg(cy, CD1400_RBPR, ibpr);
	}

	opt = CD1400_CCR_CMDCHANCTL | CD1400_CCR_XMTEN
	    | (ISSET(t->c_cflag, CREAD) ? CD1400_CCR_RCVEN : CD1400_CCR_RCVDIS);

	if (opt != cy->cy_channel_control) {
		cy->cy_channel_control = opt;
		cd1400_channel_cmd(cy, opt);
	}

	/* compute COR1 contents */
	opt = 0;
	if (ISSET(t->c_cflag, PARENB)) {
		if (ISSET(t->c_cflag, PARODD))
			opt |= CD1400_COR1_PARODD;
		opt |= CD1400_COR1_PARNORMAL;
	}

	if (!ISSET(t->c_iflag, INPCK))
		opt |= CD1400_COR1_NOINPCK;	/* no parity checking */

	if (ISSET(t->c_cflag, CSTOPB))
		opt |= CD1400_COR1_STOP2;

	switch (t->c_cflag & CSIZE) {
	case CS5:
		opt |= CD1400_COR1_CS5;
		break;

	case CS6:
		opt |= CD1400_COR1_CS6;
		break;

	case CS7:
		opt |= CD1400_COR1_CS7;
		break;

	default:
		opt |= CD1400_COR1_CS8;
		break;
	}

	cd_write_reg(cy, CD1400_COR1, opt);

#ifdef CY_DEBUG
	printf("cor1 = 0x%x...", opt);
#endif

	/*
	 * use the CD1400 automatic CTS flow control if CRTSCTS is set
	 *
	 * CD1400_COR2_ETC is used because breaks are generated with
	 * embedded transmit commands
	 */
	cd_write_reg(cy, CD1400_COR2,
	    CD1400_COR2_ETC |
	    (ISSET(t->c_cflag, CRTSCTS) ? CD1400_COR2_CCTS_OFLOW : 0));

	cd_write_reg(cy, CD1400_COR3, RX_FIFO_THRESHOLD);

	cd1400_channel_cmd(cy,
	    CD1400_CCR_CMDCORCHG |
	    CD1400_CCR_COR1 | CD1400_CCR_COR2 | CD1400_CCR_COR3);

	cd_write_reg(cy, CD1400_COR4, CD1400_COR4_PFO_EXCEPTION);
	cd_write_reg(cy, CD1400_COR5, 0);

	/*
	 * set modem change option registers to generate interrupts
	 * on carrier detect changes.
	 *
	 * if hardware RTS handshaking is used (CY_HW_RTS, DTR and RTS lines
	 * exchanged), also set the handshaking threshold.
	 */
#ifdef CY_HW_RTS
	cd_write_reg(cy, CD1400_MCOR1, CD1400_MCOR1_CDzd |
	    (ISSET(t->c_cflag, CRTSCTS) ? RX_DTR_THRESHOLD : 0));
#else
	cd_write_reg(cy, CD1400_MCOR1, CD1400_MCOR1_CDzd);
#endif /* CY_HW_RTS */

	cd_write_reg(cy, CD1400_MCOR2, CD1400_MCOR2_CDod);

	/*
	 * set receive timeout to approx. 2ms
	 * could use more complex logic here...
	 * (but is it actually needed or even useful?)
	 */
	cd_write_reg(cy, CD1400_RTPR, 2);

	/*
	 * should do anything else here?
	 * XXX check MDMBUF handshaking like in com.c?
	 */

	splx(s);
	return (0);
}

/*
 * set/get modem line status
 *
 * bits can be: TIOCM_DTR, TIOCM_RTS, TIOCM_CTS, TIOCM_CD, TIOCM_RI, TIOCM_DSR
 *
 * RTS and DTR are exchanged if CY_HW_RTS is set
 *
 */
int
cy_modem_control(struct cy_port *cy, int bits, int howto)
{
	int s, msvr;

	s = spltty();

	/* select channel */
	cd_write_reg(cy, CD1400_CAR, cy->cy_port_num & CD1400_CAR_CHAN);

/* does not manipulate RTS if it is used for flow control */
	switch (howto) {
	case DMGET:
		bits = 0;
		if (cy->cy_channel_control & CD1400_CCR_RCVEN)
			bits |= TIOCM_LE;
		msvr = cd_read_reg(cy, CD1400_MSVR2);
#ifdef CY_HW_RTS
		if (cd_read_reg(cy, CD1400_MSVR1) & CD1400_MSVR1_RTS)
			bits |= TIOCM_DTR;
		if (msvr & CD1400_MSVR2_DTR)
			bits |= TIOCM_RTS;
#else
		if (cd_read_reg(cy, CD1400_MSVR1) & CD1400_MSVR1_RTS)
			bits |= TIOCM_RTS;
		if (msvr & CD1400_MSVR2_DTR)
			bits |= TIOCM_DTR;
#endif /* CY_HW_RTS */
		if (msvr & CD1400_MSVR2_CTS)
			bits |= TIOCM_CTS;
		if (msvr & CD1400_MSVR2_CD)
			bits |= TIOCM_CD;
		if (msvr & CD1400_MSVR2_DSR)	/* not connected on some
						   Cyclom cards? */
			bits |= TIOCM_DSR;
		if (msvr & CD1400_MSVR2_RI)	/* not connected on
						   Cyclom-8Y cards? */
			bits |= TIOCM_RI;
		splx(s);
		return (bits);

	case DMSET: /* replace old values with new ones */
#ifdef CY_HW_RTS
		if (!ISSET(cy->cy_tty->t_cflag, CRTSCTS))
			cd_write_reg(cy, CD1400_MSVR2,
			    ((bits & TIOCM_RTS) ? CD1400_MSVR2_DTR : 0));
		cd_write_reg(cy, CD1400_MSVR1,
		    ((bits & TIOCM_DTR) ? CD1400_MSVR1_RTS : 0));
#else
		if (!ISSET(cy->cy_tty->t_cflag, CRTSCTS))
			cd_write_reg(cy, CD1400_MSVR1,
			    ((bits & TIOCM_RTS) ? CD1400_MSVR1_RTS : 0));
		cd_write_reg(cy, CD1400_MSVR2,
		    ((bits & TIOCM_DTR) ? CD1400_MSVR2_DTR : 0));
#endif /* CY_HW_RTS */
		break;

	case DMBIS: /* set bits */
#ifdef CY_HW_RTS
		if (!ISSET(cy->cy_tty->t_cflag, CRTSCTS) &&
		    (bits & TIOCM_RTS) != 0)
			cd_write_reg(cy, CD1400_MSVR2, CD1400_MSVR2_DTR);
		if (bits & TIOCM_DTR)
			cd_write_reg(cy, CD1400_MSVR1, CD1400_MSVR1_RTS);
#else
		if (!ISSET(cy->cy_tty->t_cflag, CRTSCTS) &&
		    (bits & TIOCM_RTS) != 0)
			cd_write_reg(cy, CD1400_MSVR1, CD1400_MSVR1_RTS);
		if (bits & TIOCM_DTR)
			cd_write_reg(cy, CD1400_MSVR2, CD1400_MSVR2_DTR);
#endif /* CY_HW_RTS */
		break;

	case DMBIC: /* clear bits */
#ifdef CY_HW_RTS
		if (!ISSET(cy->cy_tty->t_cflag, CRTSCTS) &&
		    (bits & TIOCM_RTS))
			cd_write_reg(cy, CD1400_MSVR2, 0);
		if (bits & TIOCM_DTR)
			cd_write_reg(cy, CD1400_MSVR1, 0);
#else
		if (!ISSET(cy->cy_tty->t_cflag, CRTSCTS) &&
		    (bits & TIOCM_RTS))
			cd_write_reg(cy, CD1400_MSVR1, 0);
		if (bits & TIOCM_DTR)
			cd_write_reg(cy, CD1400_MSVR2, 0);
#endif /* CY_HW_RTS */
		break;
	}
	splx(s);
	return (0);
}

/*
 * Upper-level handler loop (called from timer interrupt?)
 * This routine is common for multiple cards
 */
void
cy_poll(void *arg)
{
	int port;
	struct cy_softc *sc = arg;
	struct cy_port *cy;
	struct tty *tp;
	static int counter = 0;
#ifdef CY_DEBUG1
	int did_something;
#endif

	int s;

	s = spltty();

	if (sc->sc_events == 0 && ++counter < 200) {
		splx(s);
		goto out;
	}

	sc->sc_events = 0;
	splx(s);

#ifdef CY_DEBUG1
	sc->sc_poll_count1++;
	did_something = 0;
#endif

	for (port = 0; port < sc->sc_nports; port++) {
		cy = &sc->sc_ports[port];
		if ((tp = cy->cy_tty) == NULL || cy->cy_ibuf == NULL ||
		    !ISSET(tp->t_state, TS_ISOPEN | TS_WOPEN))
			continue;

		/*
		 * handle received data
		 */
		while (cy->cy_ibuf_rd_ptr != cy->cy_ibuf_wr_ptr) {
			u_char line_stat;
			int chr;

			line_stat = cy->cy_ibuf_rd_ptr[0];
			chr = cy->cy_ibuf_rd_ptr[1];

			if (line_stat &
			    (CD1400_RDSR_BREAK|CD1400_RDSR_FE))
				chr |= TTY_FE;
			if (line_stat & CD1400_RDSR_PE)
				chr |= TTY_PE;

			/*
			 * on an overrun error the data is treated as
			 * good just as it should be.
			 */

#ifdef CY_DEBUG
			printf("%s port %d ttyinput 0x%x\n",
			    sc->sc_dev.dv_xname, port, chr);
#endif

			(*linesw[tp->t_line].l_rint)(chr, tp);

			s = spltty(); /* really necessary? */
			if ((cy->cy_ibuf_rd_ptr += 2) ==
			    cy->cy_ibuf_end)
				cy->cy_ibuf_rd_ptr = cy->cy_ibuf;
			splx(s);

#ifdef CY_DEBUG1
			did_something = 1;
#endif
		}

#ifndef CY_HW_RTS
		/*
		 * If we don't have any received data in ibuf and
		 * CRTSCTS is on and RTS is turned off, it is time
		 * to turn RTS back on
		 */
		if (ISSET(tp->t_cflag, CRTSCTS)) {
			/* we can't use cy_modem_control() here as it
			    doesn't change RTS if RTSCTS is on */
			cd_write_reg(cy, CD1400_CAR,
			    port & CD1400_CAR_CHAN);

			if ((cd_read_reg(cy,
			    CD1400_MSVR1) & CD1400_MSVR1_RTS) == 0) {
				cd_write_reg(cy, CD1400_MSVR1,
				    CD1400_MSVR1_RTS);
#ifdef CY_DEBUG1
				did_something = 1;
#endif
			}
		}
#endif /* CY_HW_RTS */

		/*
		 * handle carrier changes
		 */
		s = spltty();
		if (ISSET(cy->cy_flags, CYF_CARRIER_CHANGED)) {
			int carrier;

			CLR(cy->cy_flags, CYF_CARRIER_CHANGED);
			splx(s);

			carrier = ((cy->cy_carrier_stat &
			    CD1400_MSVR2_CD) != 0);

#ifdef CY_DEBUG
			printf("%s: cy_poll: carrier change "
			    "(port %d, carrier %d)\n",
			    sc->sc_dev.dv_xname, port, carrier);
#endif
			if (CY_DIALIN(tp->t_dev) &&
			    !(*linesw[tp->t_line].l_modem)(tp, carrier))
				cy_modem_control(cy, TIOCM_DTR, DMBIC);

#ifdef CY_DEBUG1
			did_something = 1;
#endif
		} else {
			splx(s);
		}

		s = spltty();
		if (ISSET(cy->cy_flags, CYF_START)) {
			CLR(cy->cy_flags, CYF_START);
			splx(s);

			(*linesw[tp->t_line].l_start)(tp);

#ifdef CY_DEBUG1
			did_something = 1;
#endif
		} else {
			splx(s);
		}

		/* could move this to even upper level... */
		if (cy->cy_fifo_overruns) {
			cy->cy_fifo_overruns = 0;
			/* doesn't report overrun count,
			   but shouldn't really matter */
			log(LOG_WARNING, "%s: port %d fifo overrun\n",
			    sc->sc_dev.dv_xname, port);
		}
		if (cy->cy_ibuf_overruns) {
			cy->cy_ibuf_overruns = 0;
			log(LOG_WARNING, "%s: port %d ibuf overrun\n",
			    sc->sc_dev.dv_xname, port);
		}
	} /* for(port...) */
#ifdef CY_DEBUG1
	if (did_something && counter >= 200)
		sc->sc_poll_count2++;
#endif

	counter = 0;

out:
	timeout_add(&sc->sc_poll_to, 1);
}

/*
 * hardware interrupt routine
 */
int
cy_intr(void *arg)
{
	struct cy_softc *sc = arg;
	struct cy_port *cy;
	int cy_chip, stat;
	int int_serviced = -1;

	/*
	 * Check interrupt status of each CD1400 chip on this card
	 * (multiple cards cannot share the same interrupt)
	 */
	for (cy_chip = 0; cy_chip < sc->sc_nr_cd1400s; cy_chip++) {

		stat = cd_read_reg_sc(sc, cy_chip, CD1400_SVRR);
		if (stat == 0)
			continue;

		if (ISSET(stat, CD1400_SVRR_RXRDY)) {
			u_char save_car, save_rir, serv_type;
			u_char line_stat, recv_data, n_chars;
			u_char *buf_p;

			save_rir = cd_read_reg_sc(sc, cy_chip, CD1400_RIR);
			save_car = cd_read_reg_sc(sc, cy_chip, CD1400_CAR);
			/* enter rx service */
			cd_write_reg_sc(sc, cy_chip, CD1400_CAR, save_rir);

			serv_type = cd_read_reg_sc(sc, cy_chip, CD1400_RIVR);
			cy = &sc->sc_ports[serv_type >> 3];

#ifdef CY_DEBUG1
			cy->cy_rx_int_count++;
#endif

			buf_p = cy->cy_ibuf_wr_ptr;

			if (ISSET(serv_type, CD1400_RIVR_EXCEPTION)) {
				line_stat = cd_read_reg(cy, CD1400_RDSR);
				recv_data = cd_read_reg(cy, CD1400_RDSR);

				if (cy->cy_tty == NULL ||
				    !ISSET(cy->cy_tty->t_state, TS_ISOPEN))
					goto end_rx_serv;

#ifdef CY_DEBUG
				printf("%s port %d recv exception, "
				    "line_stat 0x%x, char 0x%x\n",
				    sc->sc_dev.dv_xname, cy->cy_port_num,
				    line_stat, recv_data);
#endif
				if (ISSET(line_stat, CD1400_RDSR_OE))
					cy->cy_fifo_overruns++;

				*buf_p++ = line_stat;
				*buf_p++ = recv_data;
				if (buf_p == cy->cy_ibuf_end)
					buf_p = cy->cy_ibuf;

				if (buf_p == cy->cy_ibuf_rd_ptr) {
					if (buf_p == cy->cy_ibuf)
						buf_p = cy->cy_ibuf_end;
					buf_p -= 2;
					cy->cy_ibuf_overruns++;
				}
				sc->sc_events = 1;
			} else { /* no exception, received data OK */
				n_chars = cd_read_reg(cy, CD1400_RDCR);

				/* If no tty or not open, discard data */
				if (cy->cy_tty == NULL ||
				    !ISSET(cy->cy_tty->t_state, TS_ISOPEN)) {
					while (n_chars--)
						cd_read_reg(cy, CD1400_RDSR);
					goto end_rx_serv;
				}

#ifdef CY_DEBUG
				printf("%s port %d receive ok %d chars\n",
				    sc->sc_dev.dv_xname, cy->cy_port_num,
				    n_chars);
#endif
				while (n_chars--) {
					*buf_p++ = 0; /* status: OK */
					*buf_p++ = cd_read_reg(cy,
					    CD1400_RDSR); /* data byte */
					if (buf_p == cy->cy_ibuf_end)
						buf_p = cy->cy_ibuf;
					if (buf_p == cy->cy_ibuf_rd_ptr) {
						if (buf_p == cy->cy_ibuf)
							buf_p = cy->cy_ibuf_end;
						buf_p -= 2;
						cy->cy_ibuf_overruns++;
						break;
					}
				}
				sc->sc_events = 1;
			}

			cy->cy_ibuf_wr_ptr = buf_p;

#ifndef CY_HW_RTS
			/* RTS handshaking for incoming data */
			if (ISSET(cy->cy_tty->t_cflag, CRTSCTS)) {
				int bf;

				bf = buf_p - cy->cy_ibuf_rd_ptr;
				if (bf < 0)
					bf += IBUF_SIZE;

				if (bf > (IBUF_SIZE/2))	/* turn RTS off */
					cd_write_reg(cy, CD1400_MSVR1, 0);
			}
#endif /* CY_HW_RTS */

		end_rx_serv:
			/* terminate service context */
			cd_write_reg(cy, CD1400_RIR, save_rir & 0x3f);
			cd_write_reg(cy, CD1400_CAR, save_car);
			int_serviced = 1;
		} /* if(rx_service...) */

		if (ISSET(stat, CD1400_SVRR_MDMCH)) {
			u_char save_car, save_mir, serv_type, modem_stat;

			save_mir = cd_read_reg_sc(sc, cy_chip, CD1400_MIR);
			save_car = cd_read_reg_sc(sc, cy_chip, CD1400_CAR);
			/* enter modem service */
			cd_write_reg_sc(sc, cy_chip, CD1400_CAR, save_mir);

			serv_type = cd_read_reg_sc(sc, cy_chip, CD1400_MIVR);
			cy = &sc->sc_ports[serv_type >> 3];

#ifdef CY_DEBUG1
			cy->cy_modem_int_count++;
#endif

			modem_stat = cd_read_reg(cy, CD1400_MSVR2);

#ifdef CY_DEBUG
			printf("%s port %d modem line change, new stat 0x%x\n",
			    sc->sc_dev.dv_xname, cy->cy_port_num, modem_stat);
#endif
			if (ISSET((cy->cy_carrier_stat ^ modem_stat),
			    CD1400_MSVR2_CD)) {
				SET(cy->cy_flags, CYF_CARRIER_CHANGED);
				sc->sc_events = 1;
			}

			cy->cy_carrier_stat = modem_stat;

			/* terminate service context */
			cd_write_reg(cy, CD1400_MIR, save_mir & 0x3f);
			cd_write_reg(cy, CD1400_CAR, save_car);
			int_serviced = 1;
		} /* if(modem_service...) */

		if (ISSET(stat, CD1400_SVRR_TXRDY)) {
			u_char save_car, save_tir, serv_type, count, ch;
			struct tty *tp;

			save_tir = cd_read_reg_sc(sc, cy_chip, CD1400_TIR);
			save_car = cd_read_reg_sc(sc, cy_chip, CD1400_CAR);
			/* enter tx service */
			cd_write_reg_sc(sc, cy_chip, CD1400_CAR, save_tir);

			serv_type = cd_read_reg_sc(sc, cy_chip, CD1400_TIVR);
			cy = &sc->sc_ports[serv_type >> 3];

#ifdef CY_DEBUG1
			cy->cy_tx_int_count++;
#endif
#ifdef CY_DEBUG
			printf("%s port %d tx service\n", sc->sc_dev.dv_xname,
			    cy->cy_port_num);
#endif

			/* stop transmitting if no tty or CYF_STOP set */
			tp = cy->cy_tty;
			if (tp == NULL || ISSET(cy->cy_flags, CYF_STOP))
				goto txdone;

			count = 0;
			if (ISSET(cy->cy_flags, CYF_SEND_NUL)) {
				cd_write_reg(cy, CD1400_TDR, 0);
				cd_write_reg(cy, CD1400_TDR, 0);
				count += 2;
				CLR(cy->cy_flags, CYF_SEND_NUL);
			}

			if (tp->t_outq.c_cc > 0) {
				SET(tp->t_state, TS_BUSY);
				while (tp->t_outq.c_cc > 0 &&
				    count < CD1400_TX_FIFO_SIZE) {
					ch = getc(&tp->t_outq);
					/* remember to double NUL characters
					   because embedded transmit commands
					   are enabled */
					if (ch == 0) {
						if (count >=
						    CD1400_TX_FIFO_SIZE-2) {
							SET(cy->cy_flags,
							    CYF_SEND_NUL);
							break;
						}

						cd_write_reg(cy, CD1400_TDR, ch);
						count++;
					}

					cd_write_reg(cy, CD1400_TDR, ch);
					count++;
				}
			} else {
				/* no data to send -- check if we should
				   start/stop a break */
				/* XXX does this cause too much delay before
				   breaks? */
				if (ISSET(cy->cy_flags, CYF_START_BREAK)) {
					cd_write_reg(cy, CD1400_TDR, 0);
					cd_write_reg(cy, CD1400_TDR, 0x81);
					CLR(cy->cy_flags, CYF_START_BREAK);
				}
				if (ISSET(cy->cy_flags, CYF_END_BREAK)) {
					cd_write_reg(cy, CD1400_TDR, 0);
					cd_write_reg(cy, CD1400_TDR, 0x83);
					CLR(cy->cy_flags, CYF_END_BREAK);
				}
			}

			if (tp->t_outq.c_cc == 0) {
txdone:
				/*
				 * No data to send or requested to stop.
				 * Disable transmit interrupt
				 */
				cd_write_reg(cy, CD1400_SRER,
				    cd_read_reg(cy, CD1400_SRER)
				    & ~CD1400_SRER_TXRDY);
				CLR(cy->cy_flags, CYF_STOP);
				CLR(tp->t_state, TS_BUSY);
			}

			if (tp->t_outq.c_cc <= tp->t_lowat) {
				SET(cy->cy_flags, CYF_START);
				sc->sc_events = 1;
			}

			/* terminate service context */
			cd_write_reg(cy, CD1400_TIR, save_tir & 0x3f);
			cd_write_reg(cy, CD1400_CAR, save_car);
			int_serviced = 1;
		} /* if(tx_service...) */
	} /* for(...all CD1400s on a card) */

	/* ensure an edge for next interrupt */
	bus_space_write_1(sc->sc_memt, sc->sc_memh,
	    CY_CLEAR_INTR<<sc->sc_bustype, 0);
	return (int_serviced);
}

/*
 * subroutine to enable CD1400 transmitter
 */
void
cy_enable_transmitter(struct cy_port *cy)
{
	int s;
	s = spltty();
	cd_write_reg(cy, CD1400_CAR, cy->cy_port_num & CD1400_CAR_CHAN);
	cd_write_reg(cy, CD1400_SRER, cd_read_reg(cy, CD1400_SRER)
	    | CD1400_SRER_TXRDY);
	splx(s);
}

/*
 * Execute a CD1400 channel command
 */
void
cd1400_channel_cmd(struct cy_port *cy, int cmd)
{
	u_int waitcnt = 5 * 8 * 1024; /* approx 5 ms */

#ifdef CY_DEBUG
	printf("c1400_channel_cmd cy %p command 0x%x\n", cy, cmd);
#endif

	/* wait until cd1400 is ready to process a new command */
	while (cd_read_reg(cy, CD1400_CCR) != 0 && waitcnt-- > 0)
		;

	if (waitcnt == 0)
		log(LOG_ERR, "cy: channel command timeout\n");

	cd_write_reg(cy, CD1400_CCR, cmd);
}

/*
 * Compute clock option register and baud rate register values
 * for a given speed. Return 0 on success, -1 on failure.
 *
 * The error between requested and actual speed seems
 * to be well within allowed limits (less than 3%)
 * with every speed value between 50 and 150000 bps.
 */
int
cy_speed(speed_t speed, int *cor, int *bpr, int cy_clock)
{
	int c, co, br;

	if (speed < 50 || speed > 150000)
		return (-1);

	for (c = 0, co = 8; co <= 2048; co <<= 2, c++) {
		br = (cy_clock + (co * speed) / 2) / (co * speed);
		if (br < 0x100) {
			*bpr = br;
			*cor = c;
			return (0);
		}
	}

	return (-1);
}