text: /*-
   * cyclades cyclom-y serial driver
   *	Andrew Herbert <andrew@werple.apana.org.au>, 17 August 1993
   *
   * Copyright (c) 1993 Andrew Herbert.
   * 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. The name Andrew Herbert may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY ``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 I 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.
   *
   *	$Id: cy.c,v 1.83 1999/01/08 19:17:46 bde Exp $
   */
  
  #include "opt_compat.h"
  #include "opt_devfs.h"
  
  #include "cy.h"
  
  /*
   * TODO:
   * Atomic COR change.
   * Consoles.
   */
  
  /*
   * Temporary compile-time configuration options.
   */
  #define	RxFifoThreshold	(CD1400_RX_FIFO_SIZE / 2)
  			/* Number of chars in the receiver FIFO before an
  			 * an interrupt is generated.  Should depend on
  			 * line speed.  Needs to be about 6 on a 486DX33
  			 * for 4 active ports at 115200 bps.  Why doesn't
  			 * 10 work?
  			 */
  #define	PollMode	/* Use polling-based irq service routine, not the
  			 * hardware svcack lines.  Must be defined for
  			 * Cyclom-16Y boards.  Less efficient for Cyclom-8Ys,
  			 * and stops 4 * 115200 bps from working.
  			 */
  #undef	Smarts		/* Enable slightly more CD1400 intelligence.  Mainly
  			 * the output CR/LF processing, plus we can avoid a
  			 * few checks usually done in ttyinput().
  			 *
  			 * XXX not fully implemented, and not particularly
  			 * worthwhile.
  			 */
  #undef	CyDebug		/* Include debugging code (not very expensive). */
  
  /* These will go away. */
  #undef	SOFT_CTS_OFLOW
  #define	SOFT_HOTCHAR
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/tty.h>
  #include <sys/proc.h>
  #include <sys/conf.h>
  #include <sys/dkstat.h>
  #include <sys/fcntl.h>
  #include <sys/interrupt.h>
  #include <sys/kernel.h>
  #include <sys/malloc.h>
  #include <sys/syslog.h>
  #ifdef DEVFS
  #include <sys/devfsext.h>
  #endif
  
  #include <machine/clock.h>
  #include <machine/ipl.h>
  #ifndef SMP
  #include <machine/lock.h>
  #endif
  
  #include <i386/isa/isa_device.h>
  #include <i386/isa/cyreg.h>
  #include <i386/isa/ic/cd1400.h>
  
  #ifdef SMP
  #define disable_intr()	COM_DISABLE_INTR()
  #define enable_intr()	COM_ENABLE_INTR()
  #endif /* SMP */
  
  /*
   * Dictionary so that I can name everything *sio* or *com* to compare with
   * sio.c.  There is also lots of ugly formatting and unnecessary ifdefs to
   * simplify the comparision.  These will go away.
   */
  #define	LSR_BI		CD1400_RDSR_BREAK
  #define	LSR_FE		CD1400_RDSR_FE
  #define	LSR_OE		CD1400_RDSR_OE
  #define	LSR_PE		CD1400_RDSR_PE
  #define	MCR_DTR		CD1400_MSVR2_DTR
  #define	MCR_RTS		CD1400_MSVR1_RTS
  #define	MSR_CTS		CD1400_MSVR2_CTS
  #define	MSR_DCD		CD1400_MSVR2_CD
  #define	MSR_DSR		CD1400_MSVR2_DSR
  #define	MSR_RI		CD1400_MSVR2_RI
  #define	NSIO		(NCY * CY_MAX_PORTS)
  #define	comconsole	cyconsole
  #define	comdefaultrate	cydefaultrate
  #define	com_events	cy_events
  #define	comhardclose	cyhardclose
  #define	commctl		cymctl
  #define	comparam	cyparam
  #define	comspeed	cyspeed
  #define	comstart	cystart
  #define	comwakeup	cywakeup
  #define	nsio_tty	ncy_tty
  #define	p_com_addr	p_cy_addr
  #define	sioattach	cyattach
  #define	sioclose	cyclose
  #define	siodevtotty	cydevtotty
  #define	siodriver	cydriver
  #define	siodtrwakeup	cydtrwakeup
  #define	siointr		cyintr
  #define	siointr1	cyintr1
  #define	sioioctl	cyioctl
  #define	sioopen		cyopen
  #define	siopoll		cypoll
  #define	sioprobe	cyprobe
  #define	sioread		cyread
  #define	siosettimeout	cysettimeout
  #define	siostop		cystop
  #define	siowrite	cywrite
  #define	sio_registered	cy_registered
  #define	sio_timeout	cy_timeout
  #define	sio_timeout_handle cy_timeout_handle
  #define	sio_timeouts_until_log	cy_timeouts_until_log
  #define	sio_tty		cy_tty
  
  #define	CY_MAX_PORTS		(CD1400_NO_OF_CHANNELS * CY_MAX_CD1400s)
  
  /* We encode the cyclom unit number (cyu) in spare bits in the IVR's. */
  #define	CD1400_xIVR_CHAN_SHIFT	3
  #define	CD1400_xIVR_CHAN	0x1F
  
  /*
   * ETC states.  com->etc may also contain a hardware ETC command value,
   * meaning that execution of that command is pending.
   */
  #define	ETC_NONE		0	/* we depend on bzero() setting this */
  #define	ETC_BREAK_STARTING	1
  #define	ETC_BREAK_STARTED	2
  #define	ETC_BREAK_ENDING	3
  #define	ETC_BREAK_ENDED		4
  
  #define	LOTS_OF_EVENTS	64	/* helps separate urgent events from input */
  #define	RS_IBUFSIZE	256
  
  #define	CALLOUT_MASK		0x80
  #define	CONTROL_MASK		0x60
  #define	CONTROL_INIT_STATE	0x20
  #define	CONTROL_LOCK_STATE	0x40
  #define	DEV_TO_UNIT(dev)	(MINOR_TO_UNIT(minor(dev)))
  #define	MINOR_MAGIC_MASK	(CALLOUT_MASK | CONTROL_MASK)
  #define	MINOR_TO_UNIT(mynor)	(((mynor) >> 16) * CY_MAX_PORTS \
  				 | (((mynor) & 0xff) & ~MINOR_MAGIC_MASK))
  
  /*
   * Input buffer watermarks.
   * The external device is asked to stop sending when the buffer exactly reaches
   * high water, or when the high level requests it.
   * The high level is notified immediately (rather than at a later clock tick)
   * when this watermark is reached.
   * The buffer size is chosen so the watermark should almost never be reached.
   * The low watermark is invisibly 0 since the buffer is always emptied all at
   * once.
   */
  #define	RS_IHIGHWATER (3 * RS_IBUFSIZE / 4)
  
  /*
   * com state bits.
   * (CS_BUSY | CS_TTGO) and (CS_BUSY | CS_TTGO | CS_ODEVREADY) must be higher
   * than the other bits so that they can be tested as a group without masking
   * off the low bits.
   *
   * The following com and tty flags correspond closely:
   *	CS_BUSY		= TS_BUSY (maintained by comstart(), siopoll() and
   *				   siostop())
   *	CS_TTGO		= ~TS_TTSTOP (maintained by comparam() and comstart())
   *	CS_CTS_OFLOW	= CCTS_OFLOW (maintained by comparam())
   *	CS_RTS_IFLOW	= CRTS_IFLOW (maintained by comparam())
   * TS_FLUSH is not used.
   * XXX I think TIOCSETA doesn't clear TS_TTSTOP when it clears IXON.
   * XXX CS_*FLOW should be CF_*FLOW in com->flags (control flags not state).
   */
  #define	CS_BUSY		0x80	/* output in progress */
  #define	CS_TTGO		0x40	/* output not stopped by XOFF */
  #define	CS_ODEVREADY	0x20	/* external device h/w ready (CTS) */
  #define	CS_CHECKMSR	1	/* check of MSR scheduled */
  #define	CS_CTS_OFLOW	2	/* use CTS output flow control */
  #define	CS_DTR_OFF	0x10	/* DTR held off */
  #define	CS_ODONE	4	/* output completed */
  #define	CS_RTS_IFLOW	8	/* use RTS input flow control */
  #define	CSE_ODONE	1	/* output transmitted */
  
  static	char const * const	error_desc[] = {
  #define	CE_OVERRUN			0
  	"silo overflow",
  #define	CE_INTERRUPT_BUF_OVERFLOW	1
  	"interrupt-level buffer overflow",
  #define	CE_TTY_BUF_OVERFLOW		2
  	"tty-level buffer overflow",
  };
  
  #define	CE_NTYPES			3
  #define	CE_RECORD(com, errnum)		(++(com)->delta_error_counts[errnum])
  
  /* types.  XXX - should be elsewhere */
  typedef u_char	bool_t;		/* boolean */
  typedef u_char volatile *cy_addr;
  
  /* queue of linear buffers */
  struct lbq {
  	u_char	*l_head;	/* next char to process */
  	u_char	*l_tail;	/* one past the last char to process */
  	struct lbq *l_next;	/* next in queue */
  	bool_t	l_queued;	/* nonzero if queued */
  };
  
  /* com device structure */
  struct com_s {
  	u_char	state;		/* miscellaneous flag bits */
  	bool_t  active_out;	/* nonzero if the callout device is open */
  #if 0
  	u_char	cfcr_image;	/* copy of value written to CFCR */
  #endif
  	u_char	etc;		/* pending Embedded Transmit Command */
  	u_char	extra_state;	/* more flag bits, separate for order trick */
  #if 0
  	u_char	fifo_image;	/* copy of value written to FIFO */
  #endif
  	u_char	gfrcr_image;	/* copy of value read from GFRCR */
  #if 0
  	bool_t	hasfifo;	/* nonzero for 16550 UARTs */
  	bool_t	loses_outints;	/* nonzero if device loses output interrupts */
  #endif
  	u_char	mcr_dtr;	/* MCR bit that is wired to DTR */
  	u_char	mcr_image;	/* copy of value written to MCR */
  	u_char	mcr_rts;	/* MCR bit that is wired to RTS */
  #if 0
  #ifdef COM_MULTIPORT
  	bool_t	multiport;	/* is this unit part of a multiport device? */
  #endif /* COM_MULTIPORT */
  	bool_t	no_irq;		/* nonzero if irq is not attached */
  	bool_t	poll;		/* nonzero if polling is required */
  	bool_t	poll_output;	/* nonzero if polling for output is required */
  #endif
  	int	unit;		/* unit	number */
  	int	dtr_wait;	/* time to hold DTR down on close (* 1/hz) */
  #if 0
  	u_int	tx_fifo_size;
  #endif
  	u_int	wopeners;	/* # processes waiting for DCD in open() */
  
  	/*
  	 * The high level of the driver never reads status registers directly
  	 * because there would be too many side effects to handle conveniently.
  	 * Instead, it reads copies of the registers stored here by the
  	 * interrupt handler.
  	 */
  	u_char	last_modem_status;	/* last MSR read by intr handler */
  	u_char	prev_modem_status;	/* last MSR handled by high level */
  
  	u_char	hotchar;	/* ldisc-specific char to be handled ASAP */
  	u_char	*ibuf;		/* start of input buffer */
  	u_char	*ibufend;	/* end of input buffer */
  	u_char	*ihighwater;	/* threshold in input buffer */
  	u_char	*iptr;		/* next free spot in input buffer */
  
  	struct lbq	obufq;	/* head of queue of output buffers */
  	struct lbq	obufs[2];	/* output buffers */
  
  	int	cy_align;	/* index for register alignment */
  	cy_addr	cy_iobase;	/* base address of this port's cyclom */
  	cy_addr	iobase;		/* base address of this port's cd1400 */
  	int	mcr_rts_reg;	/* cd1400 reg number of reg holding mcr_rts */
  
  	struct tty	*tp;	/* cross reference */
  
  	/* Initial state. */
  	struct termios	it_in;	/* should be in struct tty */
  	struct termios	it_out;
  
  	/* Lock state. */
  	struct termios	lt_in;	/* should be in struct tty */
  	struct termios	lt_out;
  
  	bool_t	do_timestamp;
  	bool_t	do_dcd_timestamp;
  	struct timeval	timestamp;
  	struct timeval	dcd_timestamp;
  
  	u_long	bytes_in;	/* statistics */
  	u_long	bytes_out;
  	u_int	delta_error_counts[CE_NTYPES];
  	u_long	error_counts[CE_NTYPES];
  
  	u_int	recv_exception;	/* exception chars received */
  	u_int	mdm;		/* modem signal changes */
  #ifdef CyDebug
  	u_int	start_count;	/* no. of calls to comstart() */
  	u_int	start_real;	/* no. of calls that did something */
  #endif
  	u_char	car;		/* CD1400 CAR shadow (if first unit in cd) */
  	u_char	channel_control;/* CD1400 CCR control command shadow */
  	u_char	cor[3];		/* CD1400 COR1-3 shadows */
  	u_char	intr_enable;	/* CD1400 SRER shadow */
  
  	/*
  	 * Ping-pong input buffers.  The extra factor of 2 in the sizes is
  	 * to allow for an error byte for each input byte.
  	 */
  #define	CE_INPUT_OFFSET		RS_IBUFSIZE
  	u_char	ibuf1[2 * RS_IBUFSIZE];
  	u_char	ibuf2[2 * RS_IBUFSIZE];
  
  	/*
  	 * Data area for output buffers.  Someday we should build the output
  	 * buffer queue without copying data.
  	 */
  	u_char	obuf1[256];
  	u_char	obuf2[256];
  #ifdef DEVFS
  	void	*devfs_token_ttyd;
  	void	*devfs_token_ttyl;
  	void	*devfs_token_ttyi;
  	void	*devfs_token_cuaa;
  	void	*devfs_token_cual;
  	void	*devfs_token_cuai;
  #endif
  };
  
  /* PCI driver entry point. */
  int	cyattach_common		__P((cy_addr cy_iobase, int cy_align));
  ointhand2_t	siointr;
  
  static	int	cy_units	__P((cy_addr cy_iobase, int cy_align));
  static	int	sioattach	__P((struct isa_device *dev));
  static	void	cd1400_channel_cmd __P((struct com_s *com, int cmd));
  static	void	cd1400_channel_cmd_wait __P((struct com_s *com));
  static	void	cd_etc		__P((struct com_s *com, int etc));
  static	int	cd_getreg	__P((struct com_s *com, int reg));
  static	void	cd_setreg	__P((struct com_s *com, int reg, int val));
  static	timeout_t siodtrwakeup;
  static	void	comhardclose	__P((struct com_s *com));
  #if 0
  static	void	siointr1	__P((struct com_s *com));
  #endif
  static	int	commctl		__P((struct com_s *com, int bits, int how));
  static	int	comparam	__P((struct tty *tp, struct termios *t));
  static	swihand_t siopoll;
  static	int	sioprobe	__P((struct isa_device *dev));
  static	void	siosettimeout	__P((void));
  static	int	comspeed	__P((speed_t speed, u_long cy_clock,
  				     int *prescaler_io));
  static	void	comstart	__P((struct tty *tp));
  static	timeout_t comwakeup;
  static	void	disc_optim	__P((struct tty	*tp, struct termios *t,
  				     struct com_s *com));
  
  #ifdef CyDebug
  void	cystatus	__P((int unit));
  #endif
  
  static char driver_name[] = "cy";
  
  /* table and macro for fast conversion from a unit number to its com struct */
  static	struct com_s	*p_com_addr[NSIO];
  #define	com_addr(unit)	(p_com_addr[unit])
  
  struct isa_driver	siodriver = {
  	sioprobe, sioattach, driver_name
  };
  
  static	d_open_t	sioopen;
  static	d_close_t	sioclose;
  static	d_read_t	sioread;
  static	d_write_t	siowrite;
  static	d_ioctl_t	sioioctl;
  static	d_stop_t	siostop;
  static	d_devtotty_t	siodevtotty;
  
  #define	CDEV_MAJOR	48
  static	struct cdevsw	sio_cdevsw = {
  	sioopen,	sioclose,	sioread,	siowrite,
  	sioioctl,	siostop,	noreset,	siodevtotty,
  	ttpoll,		nommap,		NULL,		driver_name,
  	NULL,		-1,		nodump,		nopsize,
  	D_TTY,
  };
  
  static	int	comconsole = -1;
  static	speed_t	comdefaultrate = TTYDEF_SPEED;
  static	u_int	com_events;	/* input chars + weighted output completions */
  static	bool_t	sio_registered;
  static	int	sio_timeout;
  static	int	sio_timeouts_until_log;
  static	struct	callout_handle sio_timeout_handle
      = CALLOUT_HANDLE_INITIALIZER(&sio_timeout_handle);
  #if 0 /* XXX */
  static struct tty	*sio_tty[NSIO];
  #else
  static struct tty	sio_tty[NSIO];
  #endif
  static	const int	nsio_tty = NSIO;
  
  #ifdef CyDebug
  static	u_int	cd_inbs;
  static	u_int	cy_inbs;
  static	u_int	cd_outbs;
  static	u_int	cy_outbs;
  static	u_int	cy_svrr_probes;
  static	u_int	cy_timeouts;
  #endif
  
  static	int	cy_chip_offset[] = {
  	0x0000, 0x0400, 0x0800, 0x0c00, 0x0200, 0x0600, 0x0a00, 0x0e00,
  };
  static	int	cy_nr_cd1400s[NCY];
  static	int	cy_total_devices;
  #undef	RxFifoThreshold
  static	int	volatile RxFifoThreshold = (CD1400_RX_FIFO_SIZE / 2);
  
  static int
  sioprobe(dev)
  	struct isa_device	*dev;
  {
  	cy_addr	iobase;
  
  	iobase = (cy_addr)dev->id_maddr;
  
  	/* Cyclom-16Y hardware reset (Cyclom-8Ys don't care) */
  	cy_inb(iobase, CY16_RESET, 0);	/* XXX? */
  	DELAY(500);	/* wait for the board to get its act together */
  
  	/* this is needed to get the board out of reset */
  	cy_outb(iobase, CY_CLEAR_INTR, 0, 0);
  	DELAY(500);
  
  	return (cy_units(iobase, 0) == 0 ? 0 : -1);
  }
  
  static int
  cy_units(cy_iobase, cy_align)
  	cy_addr	cy_iobase;
  	int	cy_align;
  {
  	int	cyu;
  	u_char	firmware_version;
  	int	i;
  	cy_addr	iobase;
  
  	for (cyu = 0; cyu < CY_MAX_CD1400s; ++cyu) {
  		iobase = cy_iobase + (cy_chip_offset[cyu] << cy_align);
  
  		/* wait for chip to become ready for new command */
  		for (i = 0; i < 10; i++) {
  			DELAY(50);
  			if (!cd_inb(iobase, CD1400_CCR, cy_align))
  				break;
  		}
  
  		/* clear the GFRCR register */
  		cd_outb(iobase, CD1400_GFRCR, cy_align, 0);
  
  		/* issue a reset command */
  		cd_outb(iobase, CD1400_CCR, cy_align,
  			CD1400_CCR_CMDRESET | CD1400_CCR_FULLRESET);
  
  		/* wait for the CD1400 to initialize itself */
  		for (i = 0; i < 200; i++) {
  			DELAY(50);
  
  			/* retrieve firmware version */
  			firmware_version = cd_inb(iobase, CD1400_GFRCR,
  						  cy_align);
  			if ((firmware_version & 0xf0) == 0x40)
  				break;
  		}
  
  		/*
  		 * Anything in the 0x40-0x4F range is fine.
  		 * If one CD1400 is bad then we don't support higher
  		 * numbered good ones on this board.
  		 */
  		if ((firmware_version & 0xf0) != 0x40)
  			break;
  	}
  	return (cyu);
  }
  
  static int
  sioattach(isdp)
  	struct isa_device	*isdp;
  {
  	int	adapter;
  
  	adapter = cyattach_common((cy_addr) isdp->id_maddr, 0);
  	if (adapter < 0)
  		return (0);
  
  	/*
  	 * XXX
  	 * This kludge is to allow ISA/PCI device specifications in the
  	 * kernel config file to be in any order.
  	 */
  	if (isdp->id_unit != adapter) {
  		printf("cy%d: attached as cy%d\n", isdp->id_unit, adapter);
  		isdp->id_unit = adapter;	/* XXX */
  	}
  	isdp->id_ointr = siointr;
  	isdp->id_ri_flags |= RI_FAST;
  	return (1);
  }
  
  int
  cyattach_common(cy_iobase, cy_align)
  	cy_addr	cy_iobase;
  	int	cy_align;
  {
  	int	adapter;
  	int	cyu;
  	dev_t	dev;
  	u_char	firmware_version;
  	cy_addr	iobase;
  	int	ncyu;
  	int	unit;
  
  	adapter = cy_total_devices;
  	if ((u_int)adapter >= NCY) {
  		printf(
  	"cy%d: can't attach adapter: insufficient cy devices configured\n",
  		       adapter);
  		return (-1);
  	}
  	ncyu = cy_units(cy_iobase, cy_align);
  	if (ncyu == 0)
  		return (-1);
  	cy_nr_cd1400s[adapter] = ncyu;
  	cy_total_devices++;
  
  	unit = adapter * CY_MAX_PORTS;
  	for (cyu = 0; cyu < ncyu; ++cyu) {
  		int	cdu;
  
  		iobase = (cy_addr) (cy_iobase
  				    + (cy_chip_offset[cyu] << cy_align));
  		firmware_version = cd_inb(iobase, CD1400_GFRCR, cy_align);
  
  		/* Set up a receive timeout period of than 1+ ms. */
  		cd_outb(iobase, CD1400_PPR, cy_align,
  			howmany(CY_CLOCK(firmware_version)
  				/ CD1400_PPR_PRESCALER, 1000));
  
  		for (cdu = 0; cdu < CD1400_NO_OF_CHANNELS; ++cdu, ++unit) {
  			struct com_s	*com;
  			int		s;
  
  	com = malloc(sizeof *com, M_DEVBUF, M_NOWAIT);
  	if (com == NULL)
  		break;
  	bzero(com, sizeof *com);
  	com->unit = unit;
  			com->gfrcr_image = firmware_version;
  			if (CY_RTS_DTR_SWAPPED(firmware_version)) {
  				com->mcr_dtr = MCR_RTS;
  				com->mcr_rts = MCR_DTR;
  				com->mcr_rts_reg = CD1400_MSVR2;
  			} else {
  				com->mcr_dtr = MCR_DTR;
  				com->mcr_rts = MCR_RTS;
  				com->mcr_rts_reg = CD1400_MSVR1;
  			}
  	com->dtr_wait = 3 * hz;
  	com->iptr = com->ibuf = com->ibuf1;
  	com->ibufend = com->ibuf1 + RS_IBUFSIZE;
  	com->ihighwater = com->ibuf1 + RS_IHIGHWATER;
  	com->obufs[0].l_head = com->obuf1;
  	com->obufs[1].l_head = com->obuf2;
  
  			com->cy_align = cy_align;
  			com->cy_iobase = cy_iobase;
  	com->iobase = iobase;
  			com->car = ~CD1400_CAR_CHAN;
  
  	/*
  	 * We don't use all the flags from <sys/ttydefaults.h> since they
  	 * are only relevant for logins.  It's important to have echo off
  	 * initially so that the line doesn't start blathering before the
  	 * echo flag can be turned off.
  	 */
  	com->it_in.c_iflag = 0;
  	com->it_in.c_oflag = 0;
  	com->it_in.c_cflag = TTYDEF_CFLAG;
  	com->it_in.c_lflag = 0;
  	if (unit == comconsole) {
  		com->it_in.c_iflag = TTYDEF_IFLAG;
  		com->it_in.c_oflag = TTYDEF_OFLAG;
  		com->it_in.c_cflag = TTYDEF_CFLAG | CLOCAL;
  		com->it_in.c_lflag = TTYDEF_LFLAG;
  		com->lt_out.c_cflag = com->lt_in.c_cflag = CLOCAL;
  	}
  	termioschars(&com->it_in);
  	com->it_in.c_ispeed = com->it_in.c_ospeed = comdefaultrate;
  	com->it_out = com->it_in;
  
  	s = spltty();
  	com_addr(unit) = com;
  	splx(s);
  
  	if (!sio_registered) {
  		dev = makedev(CDEV_MAJOR, 0);
  		cdevsw_add(&dev, &sio_cdevsw, NULL);
  		register_swi(SWI_TTY, siopoll);
  		sio_registered = TRUE;
  	}
  #ifdef DEVFS
  	com->devfs_token_ttyd = devfs_add_devswf(&sio_cdevsw,
  		unit, DV_CHR,
  		UID_ROOT, GID_WHEEL, 0600, "ttyc%r%r", adapter,
  		unit % CY_MAX_PORTS);
  	com->devfs_token_ttyi = devfs_add_devswf(&sio_cdevsw,
  		unit | CONTROL_INIT_STATE, DV_CHR,
  		UID_ROOT, GID_WHEEL, 0600, "ttyic%r%r", adapter,
  		unit % CY_MAX_PORTS);
  	com->devfs_token_ttyl = devfs_add_devswf(&sio_cdevsw,
  		unit | CONTROL_LOCK_STATE, DV_CHR,
  		UID_ROOT, GID_WHEEL, 0600, "ttylc%r%r", adapter,
  		unit % CY_MAX_PORTS);
  	com->devfs_token_cuaa = devfs_add_devswf(&sio_cdevsw,
  		unit | CALLOUT_MASK, DV_CHR,
  		UID_UUCP, GID_DIALER, 0660, "cuac%r%r", adapter,
  		unit % CY_MAX_PORTS);
  	com->devfs_token_cuai = devfs_add_devswf(&sio_cdevsw,
  		unit | CALLOUT_MASK | CONTROL_INIT_STATE, DV_CHR,
  		UID_UUCP, GID_DIALER, 0660, "cuaic%r%r", adapter,
  		unit % CY_MAX_PORTS);
  	com->devfs_token_cual = devfs_add_devswf(&sio_cdevsw,
  		unit | CALLOUT_MASK | CONTROL_LOCK_STATE, DV_CHR,
  		UID_UUCP, GID_DIALER, 0660, "cualc%r%r", adapter,
  		unit % CY_MAX_PORTS);
  #endif
  		}
  	}
  
  	/* ensure an edge for the next interrupt */
  	cy_outb(cy_iobase, CY_CLEAR_INTR, cy_align, 0);
  
  	return (adapter);
  }
  
  static int
  sioopen(dev, flag, mode, p)
  	dev_t		dev;
  	int		flag;
  	int		mode;
  	struct proc	*p;
  {
  	struct com_s	*com;
  	int		error;
  	int		mynor;
  	int		s;
  	struct tty	*tp;
  	int		unit;
  
  	mynor = minor(dev);
  	unit = MINOR_TO_UNIT(mynor);
  	if ((u_int) unit >= NSIO || (com = com_addr(unit)) == NULL)
  		return (ENXIO);
  	if (mynor & CONTROL_MASK)
  		return (0);
  #if 0 /* XXX */
  	tp = com->tp = sio_tty[unit] = ttymalloc(sio_tty[unit]);
  #else
  	tp = com->tp = &sio_tty[unit];
  #endif
  	s = spltty();
  	/*
  	 * We jump to this label after all non-interrupted sleeps to pick
  	 * up any changes of the device state.
  	 */
  open_top:
  	while (com->state & CS_DTR_OFF) {
  		error = tsleep(&com->dtr_wait, TTIPRI | PCATCH, "cydtr", 0);
  		if (error != 0)
  			goto out;
  	}
  	if (tp->t_state & TS_ISOPEN) {
  		/*
  		 * The device is open, so everything has been initialized.
  		 * Handle conflicts.
  		 */
  		if (mynor & CALLOUT_MASK) {
  			if (!com->active_out) {
  				error = EBUSY;
  				goto out;
  			}
  		} else {
  			if (com->active_out) {
  				if (flag & O_NONBLOCK) {
  					error = EBUSY;
  					goto out;
  				}
  				error =	tsleep(&com->active_out,
  					       TTIPRI | PCATCH, "cybi", 0);
  				if (error != 0)
  					goto out;
  				goto open_top;
  			}
  		}
  		if (tp->t_state & TS_XCLUDE && p->p_ucred->cr_uid != 0) {
  			error = EBUSY;
  			goto out;
  		}
  	} else {
  		/*
  		 * The device isn't open, so there are no conflicts.
  		 * Initialize it.  Initialization is done twice in many
  		 * cases: to preempt sleeping callin opens if we are
  		 * callout, and to complete a callin open after DCD rises.
  		 */
  		tp->t_oproc = comstart;
  		tp->t_param = comparam;
  		tp->t_dev = dev;
  		tp->t_termios = mynor & CALLOUT_MASK
  				? com->it_out : com->it_in;
  		tp->t_ififosize = 2 * RS_IBUFSIZE;
  		tp->t_ispeedwat = (speed_t)-1;
  		tp->t_ospeedwat = (speed_t)-1;
  
  		/* Encode per-board unit in LIVR for access in intr routines. */
  		cd_setreg(com, CD1400_LIVR,
  			  (unit & CD1400_xIVR_CHAN) << CD1400_xIVR_CHAN_SHIFT);
  
  		(void)commctl(com, TIOCM_DTR | TIOCM_RTS, DMSET);
  #if 0
  		com->poll = com->no_irq;
  		com->poll_output = com->loses_outints;
  #endif
  		++com->wopeners;
  		error = comparam(tp, &tp->t_termios);
  		--com->wopeners;
  		if (error != 0)
  			goto out;
  #if 0
  		if (com->hasfifo) {
  			/*
  			 * (Re)enable and flush fifos.
  			 *
  			 * Certain SMC chips cause problems if the fifos
  			 * are enabled while input is ready.  Turn off the
  			 * fifo if necessary to clear the input.  We test
  			 * the input ready bit after enabling the fifos
  			 * since we've already enabled them in comparam()
  			 * and to handle races between enabling and fresh
  			 * input.
  			 */
  			while (TRUE) {
  				outb(iobase + com_fifo,
  				     FIFO_RCV_RST | FIFO_XMT_RST
  				     | com->fifo_image);
  				DELAY(100);
  				if (!(inb(com->line_status_port) & LSR_RXRDY))
  					break;
  				outb(iobase + com_fifo, 0);
  				DELAY(100);
  				(void) inb(com->data_port);
  			}
  		}
  
  		disable_intr();
  		(void) inb(com->line_status_port);
  		(void) inb(com->data_port);
  		com->prev_modem_status = com->last_modem_status
  		    = inb(com->modem_status_port);
  		outb(iobase + com_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS
  				       | IER_EMSC);
  		enable_intr();
  #else /* !0 */
  		/*
  		 * Flush fifos.  This requires a full channel reset which
  		 * also disables the transmitter and receiver.  Recover
  		 * from this.
  		 */
  		cd1400_channel_cmd(com,
  				   CD1400_CCR_CMDRESET | CD1400_CCR_CHANRESET);
  		cd1400_channel_cmd(com, com->channel_control);
  
  		disable_intr();
  		com->prev_modem_status = com->last_modem_status
  		    = cd_getreg(com, CD1400_MSVR2);
  		cd_setreg(com, CD1400_SRER,
  			  com->intr_enable
  			  = CD1400_SRER_MDMCH | CD1400_SRER_RXDATA);
  		enable_intr();
  #endif /* 0 */
  		/*
  		 * Handle initial DCD.  Callout devices get a fake initial
  		 * DCD (trapdoor DCD).  If we are callout, then any sleeping
  		 * callin opens get woken up and resume sleeping on "cybi"
  		 * instead of "cydcd".
  		 */
  		/*
  		 * XXX `mynor & CALLOUT_MASK' should be
  		 * `tp->t_cflag & (SOFT_CARRIER | TRAPDOOR_CARRIER) where
  		 * TRAPDOOR_CARRIER is the default initial state for callout
  		 * devices and SOFT_CARRIER is like CLOCAL except it hides
  		 * the true carrier.
  		 */
  		if (com->prev_modem_status & MSR_DCD || mynor & CALLOUT_MASK)
  			(*linesw[tp->t_line].l_modem)(tp, 1);
  	}
  	/*
  	 * Wait for DCD if necessary.
  	 */
  	if (!(tp->t_state & TS_CARR_ON) && !(mynor & CALLOUT_MASK)
  	    && !(tp->t_cflag & CLOCAL) && !(flag & O_NONBLOCK)) {
  		++com->wopeners;
  		error = tsleep(TSA_CARR_ON(tp), TTIPRI | PCATCH, "cydcd", 0);
  		--com->wopeners;
  		if (error != 0)
  			goto out;
  		goto open_top;
  	}
  	error =	(*linesw[tp->t_line].l_open)(dev, tp);
  	disc_optim(tp, &tp->t_termios, com);
  	if (tp->t_state & TS_ISOPEN && mynor & CALLOUT_MASK)
  		com->active_out = TRUE;
  	siosettimeout();
  out:
  	splx(s);
  	if (!(tp->t_state & TS_ISOPEN) && com->wopeners == 0)
  		comhardclose(com);
  	return (error);
  }
  
  static int
  sioclose(dev, flag, mode, p)
  	dev_t		dev;
  	int		flag;
  	int		mode;
  	struct proc	*p;
  {
  	struct com_s	*com;
  	int		mynor;
  	int		s;
  	struct tty	*tp;
  
  	mynor = minor(dev);
  	if (mynor & CONTROL_MASK)
  		return (0);
  	com = com_addr(MINOR_TO_UNIT(mynor));
  	tp = com->tp;
  	s = spltty();
  	cd_etc(com, CD1400_ETC_STOPBREAK);
  	(*linesw[tp->t_line].l_close)(tp, flag);
  	disc_optim(tp, &tp->t_termios, com);
  	siostop(tp, FREAD | FWRITE);
  	comhardclose(com);
  	ttyclose(tp);
  	siosettimeout();
  	splx(s);
  #ifdef broken /* session holds a ref to the tty; can't deallocate */
  	ttyfree(tp);
  	com->tp = sio_tty[unit] = NULL;
  #endif
  	return (0);
  }
  
  static void
  comhardclose(com)
  	struct com_s	*com;
  {
  	cy_addr		iobase;
  	int		s;
  	struct tty	*tp;
  	int		unit;
  
  	unit = com->unit;
  	iobase = com->iobase;
  	s = spltty();
  #if 0
  	com->poll = FALSE;
  	com->poll_output = FALSE;
  #endif
  	com->do_timestamp = 0;
  #if 0
  	outb(iobase + com_cfcr, com->cfcr_image &= ~CFCR_SBREAK);
  #else
  	/* XXX */
  	disable_intr();
  	com->etc = ETC_NONE;
  	cd_setreg(com, CD1400_COR2, com->cor[1] &= ~CD1400_COR2_ETC);
  	enable_intr();
  	cd1400_channel_cmd(com, CD1400_CCR_CMDRESET | CD1400_CCR_FTF);
  #endif
  
  	{
  #if 0
  		outb(iobase + com_ier, 0);
  #else
  		disable_intr();
  		cd_setreg(com, CD1400_SRER, com->intr_enable = 0);
  		enable_intr();
  #endif
  		tp = com->tp;
  		if (tp->t_cflag & HUPCL
  		    /*
  		     * XXX we will miss any carrier drop between here and the
  		     * next open.  Perhaps we should watch DCD even when the
  		     * port is closed; it is not sufficient to check it at
  		     * the next open because it might go up and down while
  		     * we're not watching.
  		     */
  		    || !com->active_out
  		       && !(com->prev_modem_status & MSR_DCD)
  		       && !(com->it_in.c_cflag & CLOCAL)
  		    || !(tp->t_state & TS_ISOPEN)) {
  			(void)commctl(com, TIOCM_DTR, DMBIC);
  
  			/* Disable receiver (leave transmitter enabled). */
  			com->channel_control = CD1400_CCR_CMDCHANCTL
  					       | CD1400_CCR_XMTEN
  					       | CD1400_CCR_RCVDIS;
  			cd1400_channel_cmd(com, com->channel_control);
  
  			if (com->dtr_wait != 0 && !(com->state & CS_DTR_OFF)) {
  				timeout(siodtrwakeup, com, com->dtr_wait);
  				com->state |= CS_DTR_OFF;
  			}
  		}
  	}
  #if 0
  	if (com->hasfifo) {
  		/*
  		 * Disable fifos so that they are off after controlled
  		 * reboots.  Some BIOSes fail to detect 16550s when the
  		 * fifos are enabled.
  		 */
  		outb(iobase + com_fifo, 0);
  	}
  #endif
  	com->active_out = FALSE;
  	wakeup(&com->active_out);
  	wakeup(TSA_CARR_ON(tp));	/* restart any wopeners */
  	splx(s);
  }
  
  static int
  sioread(dev, uio, flag)
  	dev_t		dev;
  	struct uio	*uio;
  	int		flag;
  {
  	int		mynor;
  	struct tty	*tp;
  
  	mynor = minor(dev);
  	if (mynor & CONTROL_MASK)
  		return (ENODEV);
  	tp = com_addr(MINOR_TO_UNIT(mynor))->tp;
  	return ((*linesw[tp->t_line].l_read)(tp, uio, flag));
  }
  
  static int
  siowrite(dev, uio, flag)
  	dev_t		dev;
  	struct uio	*uio;
  	int		flag;
  {
  	int		mynor;
  	struct tty	*tp;
  	int		unit;
  
  	mynor = minor(dev);
  	if (mynor & CONTROL_MASK)
  		return (ENODEV);
  
  	unit = MINOR_TO_UNIT(mynor);
  	tp = com_addr(unit)->tp;
  	/*
  	 * (XXX) We disallow virtual consoles if the physical console is
  	 * a serial port.  This is in case there is a display attached that
  	 * is not the console.  In that situation we don't need/want the X
  	 * server taking over the console.
  	 */
  	if (constty != NULL && unit == comconsole)
  		constty = NULL;
  #ifdef Smarts
  	/* XXX duplicate ttwrite(), but without so much output processing on
  	 * CR & LF chars.  Hardly worth the effort, given that high-throughput
  	 * sessions are raw anyhow.
  	 */
  #else
  	return ((*linesw[tp->t_line].l_write)(tp, uio, flag));
  #endif
  }
  
  static void
  siodtrwakeup(chan)
  	void	*chan;
  {
  	struct com_s	*com;
  
  	com = (struct com_s *)chan;
  	com->state &= ~CS_DTR_OFF;
  	wakeup(&com->dtr_wait);
  }
  
  void
  siointr(unit)
  	int	unit;
  {
  	int	baseu;
  	int	cy_align;
  	cy_addr	cy_iobase;
  	int	cyu;
  	cy_addr	iobase;
  	u_char	status;
  
  	COM_LOCK();	/* XXX could this be placed down lower in the loop? */
  
  	baseu = unit * CY_MAX_PORTS;
  	cy_align = com_addr(baseu)->cy_align;
  	cy_iobase = com_addr(baseu)->cy_iobase;
  
  	/* check each CD1400 in turn */
  	for (cyu = 0; cyu < cy_nr_cd1400s[unit]; ++cyu) {
  		iobase = (cy_addr) (cy_iobase
  				    + (cy_chip_offset[cyu] << cy_align));
  		/* poll to see if it has any work */
  		status = cd_inb(iobase, CD1400_SVRR, cy_align);
  		if (status == 0)
  			continue;
  #ifdef CyDebug
  		++cy_svrr_probes;
  #endif
  		/* service requests as appropriate, giving priority to RX */
  		if (status & CD1400_SVRR_RXRDY) {
  			struct com_s	*com;
  			u_int		count;
  			u_char		*ioptr;
  			u_char		line_status;
  			u_char		recv_data;
  			u_char		serv_type;
  #ifdef PollMode
  			u_char		save_rir;
  #endif
  
  #ifdef PollMode
  			save_rir = cd_inb(iobase, CD1400_RIR, cy_align);
  
  			/* enter rx service */
  			cd_outb(iobase, CD1400_CAR, cy_align, save_rir);
  			com_addr(baseu + cyu * CD1400_NO_OF_CHANNELS)->car
  			= save_rir & CD1400_CAR_CHAN;
  
  			serv_type = cd_inb(iobase, CD1400_RIVR, cy_align);
  			com = com_addr(baseu
  				       + ((serv_type >> CD1400_xIVR_CHAN_SHIFT)
  					  & CD1400_xIVR_CHAN));
  #else
  			/* ack receive service */
  			serv_type = cy_inb(iobase, CY8_SVCACKR, cy_align);
  
  			com = com_addr(baseu +
  				       + ((serv_type >> CD1400_xIVR_CHAN_SHIFT)
  					  & CD1400_xIVR_CHAN));
  #endif
  
  		if (serv_type & CD1400_RIVR_EXCEPTION) {
  			++com->recv_exception;
  			line_status = cd_inb(iobase, CD1400_RDSR, cy_align);
  			/* break/unnattached error bits or real input? */
  			recv_data = cd_inb(iobase, CD1400_RDSR, cy_align);
  #ifndef SOFT_HOTCHAR
  			if (line_status & CD1400_RDSR_SPECIAL
  			    && com->hotchar != 0)
  				setsofttty();
  #endif
  #if 1 /* XXX "intelligent" PFO error handling would break O error handling */
  			if (line_status & (LSR_PE|LSR_FE|LSR_BI)) {
  				/*
  				  Don't store PE if IGNPAR and BI if IGNBRK,
  				  this hack allows "raw" tty optimization
  				  works even if IGN* is set.
  				*/
  				if (   com->tp == NULL
  				    || !(com->tp->t_state & TS_ISOPEN)
  				    || (line_status & (LSR_PE|LSR_FE))
  				    &&  (com->tp->t_iflag & IGNPAR)
  				    || (line_status & LSR_BI)
  				    &&  (com->tp->t_iflag & IGNBRK))
  					goto cont;
  				if (   (line_status & (LSR_PE|LSR_FE))
  				    && (com->tp->t_state & TS_CAN_BYPASS_L_RINT)
  				    && ((line_status & LSR_FE)
  				    ||  (line_status & LSR_PE)
  				    &&  (com->tp->t_iflag & INPCK)))
  					recv_data = 0;
  			}
  #endif /* 1 */
  			++com->bytes_in;
  #ifdef SOFT_HOTCHAR
  			if (com->hotchar != 0 && recv_data == com->hotchar)
  				setsofttty();
  #endif
  			ioptr = com->iptr;
  			if (ioptr >= com->ibufend)
  				CE_RECORD(com, CE_INTERRUPT_BUF_OVERFLOW);
  			else {
  				if (com->do_timestamp)
  					microtime(&com->timestamp);
  				++com_events;
  				ioptr[0] = recv_data;
  				ioptr[CE_INPUT_OFFSET] = line_status;
  				com->iptr = ++ioptr;
  				if (ioptr == com->ihighwater
  				    && com->state & CS_RTS_IFLOW)
  #if 0
  					outb(com->modem_ctl_port,
  					     com->mcr_image &= ~MCR_RTS);
  #else
  					cd_outb(iobase, com->mcr_rts_reg,
  						cy_align,
  						com->mcr_image &=
  						~com->mcr_rts);
  #endif
  				if (line_status & LSR_OE)
  					CE_RECORD(com, CE_OVERRUN);
  			}
  			goto cont;
  		} else {
  			int	ifree;
  
  			count = cd_inb(iobase, CD1400_RDCR, cy_align);
  			if (!count)
  				goto cont;
  			com->bytes_in += count;
  			ioptr = com->iptr;
  			ifree = com->ibufend - ioptr;
  			if (count > ifree) {
  				count -= ifree;
  				com_events += ifree;
  				if (ifree != 0) {
  					if (com->do_timestamp)
  						microtime(&com->timestamp);
  					do {
  						recv_data = cd_inb(iobase,
  								   CD1400_RDSR,
  								   cy_align);
  #ifdef SOFT_HOTCHAR
  						if (com->hotchar != 0
  						    && recv_data
  						       == com->hotchar)
  							setsofttty();
  #endif
  						ioptr[0] = recv_data;
  						ioptr[CE_INPUT_OFFSET] = 0;
  						++ioptr;
  					} while (--ifree != 0);
  				}
  				com->delta_error_counts
  				    [CE_INTERRUPT_BUF_OVERFLOW] += count;
  				do {
  					recv_data = cd_inb(iobase, CD1400_RDSR,
  							   cy_align);
  #ifdef SOFT_HOTCHAR
  					if (com->hotchar != 0
  					    && recv_data == com->hotchar)
  						setsofttty();
  #endif
  				} while (--count != 0);
  			} else {
  				if (com->do_timestamp)
  					microtime(&com->timestamp);
  				if (ioptr <= com->ihighwater
  				    && ioptr + count > com->ihighwater
  				    && com->state & CS_RTS_IFLOW)
  #if 0
  					outb(com->modem_ctl_port,
  					     com->mcr_image &= ~MCR_RTS);
  #else
  					cd_outb(iobase, com->mcr_rts_reg,
  						cy_align,
  						com->mcr_image
  						&= ~com->mcr_rts);
  #endif
  				com_events += count;
  				do {
  					recv_data = cd_inb(iobase, CD1400_RDSR,
  							   cy_align);
  #ifdef SOFT_HOTCHAR
  					if (com->hotchar != 0
  					    && recv_data == com->hotchar)
  						setsofttty();
  #endif
  					ioptr[0] = recv_data;
  					ioptr[CE_INPUT_OFFSET] = 0;
  					++ioptr;
  				} while (--count != 0);
  			}
  			com->iptr = ioptr;
  		}
  cont:
  
  			/* terminate service context */
  #ifdef PollMode
  			cd_outb(iobase, CD1400_RIR, cy_align,
  				save_rir
  				& ~(CD1400_RIR_RDIREQ | CD1400_RIR_RBUSY));
  #else
  			cd_outb(iobase, CD1400_EOSRR, cy_align, 0);
  #endif
  		}
  		if (status & CD1400_SVRR_MDMCH) {
  			struct com_s	*com;
  			u_char	modem_status;
  #ifdef PollMode
  			u_char	save_mir;
  #else
  			u_char	vector;
  #endif
  
  #ifdef PollMode
  			save_mir = cd_inb(iobase, CD1400_MIR, cy_align);
  
  			/* enter modem service */
  			cd_outb(iobase, CD1400_CAR, cy_align, save_mir);
  			com_addr(baseu + cyu * CD1400_NO_OF_CHANNELS)->car
  			= save_mir & CD1400_CAR_CHAN;
  
  			com = com_addr(baseu + cyu * CD1400_NO_OF_CHANNELS
  				       + (save_mir & CD1400_MIR_CHAN));
  #else
  			/* ack modem service */
  			vector = cy_inb(iobase, CY8_SVCACKM, cy_align);
  
  			com = com_addr(baseu
  				       + ((vector >> CD1400_xIVR_CHAN_SHIFT)
  					  & CD1400_xIVR_CHAN));
  #endif
  			++com->mdm;
  			modem_status = cd_inb(iobase, CD1400_MSVR2, cy_align);
  		if (modem_status != com->last_modem_status) {
  			if (com->do_dcd_timestamp
  			    && !(com->last_modem_status & MSR_DCD)
  			    && modem_status & MSR_DCD)
  				microtime(&com->dcd_timestamp);
  
  			/*
  			 * Schedule high level to handle DCD changes.  Note
  			 * that we don't use the delta bits anywhere.  Some
  			 * UARTs mess them up, and it's easy to remember the
  			 * previous bits and calculate the delta.
  			 */
  			com->last_modem_status = modem_status;
  			if (!(com->state & CS_CHECKMSR)) {
  				com_events += LOTS_OF_EVENTS;
  				com->state |= CS_CHECKMSR;
  				setsofttty();
  			}
  
  #ifdef SOFT_CTS_OFLOW
  			/* handle CTS change immediately for crisp flow ctl */
  			if (com->state & CS_CTS_OFLOW) {
  				if (modem_status & MSR_CTS) {
  					com->state |= CS_ODEVREADY;
  					if (com->state >= (CS_BUSY | CS_TTGO
  							   | CS_ODEVREADY)
  					    && !(com->intr_enable
  						 & CD1400_SRER_TXRDY))
  						cd_outb(iobase, CD1400_SRER,
  							cy_align,
  							com->intr_enable
  							= com->intr_enable
  							  & ~CD1400_SRER_TXMPTY
  							  | CD1400_SRER_TXRDY);
  				} else {
  					com->state &= ~CS_ODEVREADY;
  					if (com->intr_enable
  					    & CD1400_SRER_TXRDY)
  						cd_outb(iobase, CD1400_SRER,
  							cy_align,
  							com->intr_enable
  							= com->intr_enable
  							  & ~CD1400_SRER_TXRDY
  							  | CD1400_SRER_TXMPTY);
  				}
  			}
  #endif
  		}
  
  			/* terminate service context */
  #ifdef PollMode
  			cd_outb(iobase, CD1400_MIR, cy_align,
  				save_mir
  				& ~(CD1400_MIR_RDIREQ | CD1400_MIR_RBUSY));
  #else
  			cd_outb(iobase, CD1400_EOSRR, cy_align, 0);
  #endif
  		}
  		if (status & CD1400_SVRR_TXRDY) {
  			struct com_s	*com;
  #ifdef PollMode
  			u_char	save_tir;
  #else
  			u_char	vector;
  #endif
  
  #ifdef PollMode
  			save_tir = cd_inb(iobase, CD1400_TIR, cy_align);
  
  			/* enter tx service */
  			cd_outb(iobase, CD1400_CAR, cy_align, save_tir);
  			com_addr(baseu + cyu * CD1400_NO_OF_CHANNELS)->car
  			= save_tir & CD1400_CAR_CHAN;
  
  			com = com_addr(baseu
  				       + cyu * CD1400_NO_OF_CHANNELS
  				       + (save_tir & CD1400_TIR_CHAN));
  #else
  			/* ack transmit service */
  			vector = cy_inb(iobase, CY8_SVCACKT, cy_align);
  
  			com = com_addr(baseu
  				       + ((vector >> CD1400_xIVR_CHAN_SHIFT)
  					  & CD1400_xIVR_CHAN));
  #endif
  
  			if (com->etc != ETC_NONE) {
  				if (com->intr_enable & CD1400_SRER_TXRDY) {
  					/*
  					 * Here due to sloppy SRER_TXRDY
  					 * enabling.  Ignore.  Come back when
  					 * tx is empty.
  					 */
  					cd_outb(iobase, CD1400_SRER, cy_align,
  						com->intr_enable
  						= com->intr_enable
  						  & ~CD1400_SRER_TXRDY
  						  | CD1400_SRER_TXMPTY);
  					goto terminate_tx_service;
  				}
  				switch (com->etc) {
  				case CD1400_ETC_SENDBREAK:
  				case CD1400_ETC_STOPBREAK:
  					/*
  					 * Start the command.  Come back on
  					 * next tx empty interrupt, hopefully
  					 * after command has been executed.
  					 */
  					cd_outb(iobase, CD1400_COR2, cy_align,
  						com->cor[1] |= CD1400_COR2_ETC);
  					cd_outb(iobase, CD1400_TDR, cy_align,
  						CD1400_ETC_CMD);
  					cd_outb(iobase, CD1400_TDR, cy_align,
  						com->etc);
  					if (com->etc == CD1400_ETC_SENDBREAK)
  						com->etc = ETC_BREAK_STARTING;
  					else
  						com->etc = ETC_BREAK_ENDING;
  					goto terminate_tx_service;
  				case ETC_BREAK_STARTING:
  					/*
  					 * BREAK is now on.  Continue with
  					 * SRER_TXMPTY processing, hopefully
  					 * don't come back.
  					 */
  					com->etc = ETC_BREAK_STARTED;
  					break;
  				case ETC_BREAK_STARTED:
  					/*
  					 * Came back due to sloppy SRER_TXMPTY
  					 * enabling.  Hope again.
  					 */
  					break;
  				case ETC_BREAK_ENDING:
  					/*
  					 * BREAK is now off.  Continue with
  					 * SRER_TXMPTY processing and don't
  					 * come back.  The SWI handler will
  					 * restart tx interrupts if necessary.
  					 */
  					cd_outb(iobase, CD1400_COR2, cy_align,
  						com->cor[1]
  						&= ~CD1400_COR2_ETC);
  					com->etc = ETC_BREAK_ENDED;
  					if (!(com->state & CS_ODONE)) {
  						com_events += LOTS_OF_EVENTS;
  						com->state |= CS_ODONE;
  						setsofttty();
  					}
  					break;
  				case ETC_BREAK_ENDED:
  					/*
  					 * Shouldn't get here.  Hope again.
  					 */
  					break;
  				}
  			}
  			if (com->intr_enable & CD1400_SRER_TXMPTY) {
  				if (!(com->extra_state & CSE_ODONE)) {
  					com_events += LOTS_OF_EVENTS;
  					com->extra_state |= CSE_ODONE;
  					setsofttty();
  				}
  				cd_outb(iobase, CD1400_SRER, cy_align,
  					com->intr_enable
  					&= ~CD1400_SRER_TXMPTY);
  				goto terminate_tx_service;
  			}
  		if (com->state >= (CS_BUSY | CS_TTGO | CS_ODEVREADY)) {
  			u_char	*ioptr;
  			u_int	ocount;
  
  			ioptr = com->obufq.l_head;
  				ocount = com->obufq.l_tail - ioptr;
  				if (ocount > CD1400_TX_FIFO_SIZE)
  					ocount = CD1400_TX_FIFO_SIZE;
  				com->bytes_out += ocount;
  				do
  					cd_outb(iobase, CD1400_TDR, cy_align,
  						*ioptr++);
  				while (--ocount != 0);
  			com->obufq.l_head = ioptr;
  			if (ioptr >= com->obufq.l_tail) {
  				struct lbq	*qp;
  
  				qp = com->obufq.l_next;
  				qp->l_queued = FALSE;
  				qp = qp->l_next;
  				if (qp != NULL) {
  					com->obufq.l_head = qp->l_head;
  					com->obufq.l_tail = qp->l_tail;
  					com->obufq.l_next = qp;
  				} else {
  					/* output just completed */
  					com->state &= ~CS_BUSY;
  
  					/*
  					 * The setting of CSE_ODONE may be
  					 * stale here.  We currently only
  					 * use it when CS_BUSY is set, and
  					 * fixing it when we clear CS_BUSY
  					 * is easiest.
  					 */
  					if (com->extra_state & CSE_ODONE) {
  						com_events -= LOTS_OF_EVENTS;
  						com->extra_state &= ~CSE_ODONE;
  					}
  
  					cd_outb(iobase, CD1400_SRER, cy_align,
  						com->intr_enable
  						= com->intr_enable
  						  & ~CD1400_SRER_TXRDY
  						  | CD1400_SRER_TXMPTY);
  				}
  				if (!(com->state & CS_ODONE)) {
  					com_events += LOTS_OF_EVENTS;
  					com->state |= CS_ODONE;
  
  					/* handle at high level ASAP */
  					setsofttty();
  				}
  			}
  		}
  
  			/* terminate service context */
  terminate_tx_service:
  #ifdef PollMode
  			cd_outb(iobase, CD1400_TIR, cy_align,
  				save_tir
  				& ~(CD1400_TIR_RDIREQ | CD1400_TIR_RBUSY));
  #else
  			cd_outb(iobase, CD1400_EOSRR, cy_align, 0);
  #endif
  		}
  	}
  
  	/* ensure an edge for the next interrupt */
  	cy_outb(cy_iobase, CY_CLEAR_INTR, cy_align, 0);
  
  	schedsofttty();
  
  	COM_UNLOCK();
  }
  
  #if 0
  static void
  siointr1(com)
  	struct com_s	*com;
  {
  }
  #endif
  
  static int
  sioioctl(dev, cmd, data, flag, p)
  	dev_t		dev;
  	u_long		cmd;
  	caddr_t		data;
  	int		flag;
  	struct proc	*p;
  {
  	struct com_s	*com;
  	int		error;
  	int		mynor;
  	int		s;
  	struct tty	*tp;
  #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
  	int		oldcmd;
  	struct termios	term;
  #endif
  
  	mynor = minor(dev);
  	com = com_addr(MINOR_TO_UNIT(mynor));
  	if (mynor & CONTROL_MASK) {
  		struct termios	*ct;
  
  		switch (mynor & CONTROL_MASK) {
  		case CONTROL_INIT_STATE:
  			ct = mynor & CALLOUT_MASK ? &com->it_out : &com->it_in;
  			break;
  		case CONTROL_LOCK_STATE:
  			ct = mynor & CALLOUT_MASK ? &com->lt_out : &com->lt_in;
  			break;
  		default:
  			return (ENODEV);	/* /dev/nodev */
  		}
  		switch (cmd) {
  		case TIOCSETA:
  			error = suser(p->p_ucred, &p->p_acflag);
  			if (error != 0)
  				return (error);
  			*ct = *(struct termios *)data;
  			return (0);
  		case TIOCGETA:
  			*(struct termios *)data = *ct;
  			return (0);
  		case TIOCGETD:
  			*(int *)data = TTYDISC;
  			return (0);
  		case TIOCGWINSZ:
  			bzero(data, sizeof(struct winsize));
  			return (0);
  		default:
  			return (ENOTTY);
  		}
  	}
  	tp = com->tp;
  #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
  	term = tp->t_termios;
  	oldcmd = cmd;
  	error = ttsetcompat(tp, &cmd, data, &term);
  	if (error != 0)
  		return (error);
  	if (cmd != oldcmd)
  		data = (caddr_t)&term;
  #endif
  	if (cmd == TIOCSETA || cmd == TIOCSETAW || cmd == TIOCSETAF) {
  		int	cc;
  		struct termios *dt = (struct termios *)data;
  		struct termios *lt = mynor & CALLOUT_MASK
  				     ? &com->lt_out : &com->lt_in;
  
  		dt->c_iflag = (tp->t_iflag & lt->c_iflag)
  			      | (dt->c_iflag & ~lt->c_iflag);
  		dt->c_oflag = (tp->t_oflag & lt->c_oflag)
  			      | (dt->c_oflag & ~lt->c_oflag);
  		dt->c_cflag = (tp->t_cflag & lt->c_cflag)
  			      | (dt->c_cflag & ~lt->c_cflag);
  		dt->c_lflag = (tp->t_lflag & lt->c_lflag)
  			      | (dt->c_lflag & ~lt->c_lflag);
  		for (cc = 0; cc < NCCS; ++cc)
  			if (lt->c_cc[cc] != 0)
  				dt->c_cc[cc] = tp->t_cc[cc];
  		if (lt->c_ispeed != 0)
  			dt->c_ispeed = tp->t_ispeed;
  		if (lt->c_ospeed != 0)
  			dt->c_ospeed = tp->t_ospeed;
  	}
  	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
  	if (error != ENOIOCTL)
  		return (error);
  	s = spltty();
  	error = ttioctl(tp, cmd, data, flag);
  	disc_optim(tp, &tp->t_termios, com);
  	if (error != ENOIOCTL) {
  		splx(s);
  		return (error);
  	}
  	switch (cmd) {
  	case TIOCSBRK:
  #if 0
  		outb(iobase + com_cfcr, com->cfcr_image |= CFCR_SBREAK);
  #else
  		cd_etc(com, CD1400_ETC_SENDBREAK);
  #endif
  		break;
  	case TIOCCBRK:
  #if 0
  		outb(iobase + com_cfcr, com->cfcr_image &= ~CFCR_SBREAK);
  #else
  		cd_etc(com, CD1400_ETC_STOPBREAK);
  #endif
  		break;
  	case TIOCSDTR:
  		(void)commctl(com, TIOCM_DTR, DMBIS);
  		break;
  	case TIOCCDTR:
  		(void)commctl(com, TIOCM_DTR, DMBIC);
  		break;
  	/*
  	 * XXX should disallow changing MCR_RTS if CS_RTS_IFLOW is set.  The
  	 * changes get undone on the next call to comparam().
  	 */
  	case TIOCMSET:
  		(void)commctl(com, *(int *)data, DMSET);
  		break;
  	case TIOCMBIS:
  		(void)commctl(com, *(int *)data, DMBIS);
  		break;
  	case TIOCMBIC:
  		(void)commctl(com, *(int *)data, DMBIC);
  		break;
  	case TIOCMGET:
  		*(int *)data = commctl(com, 0, DMGET);
  		break;
  	case TIOCMSDTRWAIT:
  		/* must be root since the wait applies to following logins */
  		error = suser(p->p_ucred, &p->p_acflag);
  		if (error != 0) {
  			splx(s);
  			return (error);
  		}
  		com->dtr_wait = *(int *)data * hz / 100;
  		break;
  	case TIOCMGDTRWAIT:
  		*(int *)data = com->dtr_wait * 100 / hz;
  		break;
  	case TIOCTIMESTAMP:
  		com->do_timestamp = TRUE;
  		*(struct timeval *)data = com->timestamp;
  		break;
  	case TIOCDCDTIMESTAMP:
  		com->do_dcd_timestamp = TRUE;
  		*(struct timeval *)data = com->dcd_timestamp;
  		break;
  	default:
  		splx(s);
  		return (ENOTTY);
  	}
  	splx(s);
  	return (0);
  }
  
  static void
  siopoll()
  {
  	int		unit;
  
  #ifdef CyDebug
  	++cy_timeouts;
  #endif
  	if (com_events == 0)
  		return;
  repeat:
  	for (unit = 0; unit < NSIO; ++unit) {
  		u_char		*buf;
  		struct com_s	*com;
  		u_char		*ibuf;
  		int		incc;
  		struct tty	*tp;
  
  		com = com_addr(unit);
  		if (com == NULL)
  			continue;
  		tp = com->tp;
  		if (tp == NULL) {
  			/*
  			 * XXX forget any events related to closed devices
  			 * (actually never opened devices) so that we don't
  			 * loop.
  			 */
  			disable_intr();
  			incc = com->iptr - com->ibuf;
  			com->iptr = com->ibuf;
  			if (com->state & CS_CHECKMSR) {
  				incc += LOTS_OF_EVENTS;
  				com->state &= ~CS_CHECKMSR;
  			}
  			com_events -= incc;
  			enable_intr();
  			if (incc != 0)
  				log(LOG_DEBUG,
  				    "sio%d: %d events for device with no tp\n",
  				    unit, incc);
  			continue;
  		}
  
  		/* switch the role of the low-level input buffers */
  		if (com->iptr == (ibuf = com->ibuf)) {
  			buf = NULL;     /* not used, but compiler can't tell */
  			incc = 0;
  		} else {
  			buf = ibuf;
  			disable_intr();
  			incc = com->iptr - buf;
  			com_events -= incc;
  			if (ibuf == com->ibuf1)
  				ibuf = com->ibuf2;
  			else
  				ibuf = com->ibuf1;
  			com->ibufend = ibuf + RS_IBUFSIZE;
  			com->ihighwater = ibuf + RS_IHIGHWATER;
  			com->iptr = ibuf;
  
  			/*
  			 * There is now room for another low-level buffer full
  			 * of input, so enable RTS if it is now disabled and
  			 * there is room in the high-level buffer.
  			 */
  			if ((com->state & CS_RTS_IFLOW)
  			    && !(com->mcr_image & com->mcr_rts)
  			    && !(tp->t_state & TS_TBLOCK))
  #if 0
  				outb(com->modem_ctl_port,
  				     com->mcr_image |= MCR_RTS);
  #else
  				cd_setreg(com, com->mcr_rts_reg,
  					  com->mcr_image |= com->mcr_rts);
  #endif
  			enable_intr();
  			com->ibuf = ibuf;
  		}
  
  		if (com->state & CS_CHECKMSR) {
  			u_char	delta_modem_status;
  
  			disable_intr();
  			delta_modem_status = com->last_modem_status
  					     ^ com->prev_modem_status;
  			com->prev_modem_status = com->last_modem_status;
  			com_events -= LOTS_OF_EVENTS;
  			com->state &= ~CS_CHECKMSR;
  			enable_intr();
  			if (delta_modem_status & MSR_DCD)
  				(*linesw[tp->t_line].l_modem)
  					(tp, com->prev_modem_status & MSR_DCD);
  		}
  		if (com->extra_state & CSE_ODONE) {
  			disable_intr();
  			com_events -= LOTS_OF_EVENTS;
  			com->extra_state &= ~CSE_ODONE;
  			enable_intr();
  			if (!(com->state & CS_BUSY)) {
  				tp->t_state &= ~TS_BUSY;
  				ttwwakeup(com->tp);
  			}
  			if (com->etc != ETC_NONE) {
  				if (com->etc == ETC_BREAK_ENDED)
  					com->etc = ETC_NONE;
  				wakeup(&com->etc);
  			}
  		}
  		if (com->state & CS_ODONE) {
  			disable_intr();
  			com_events -= LOTS_OF_EVENTS;
  			com->state &= ~CS_ODONE;
  			enable_intr();
  			(*linesw[tp->t_line].l_start)(tp);
  		}
  		if (incc <= 0 || !(tp->t_state & TS_ISOPEN))
  			continue;
  		/*
  		 * Avoid the grotesquely inefficient lineswitch routine
  		 * (ttyinput) in "raw" mode.  It usually takes about 450
  		 * instructions (that's without canonical processing or echo!).
  		 * slinput is reasonably fast (usually 40 instructions plus
  		 * call overhead).
  		 */
  		if (tp->t_state & TS_CAN_BYPASS_L_RINT) {
  			if (tp->t_rawq.c_cc + incc > tp->t_ihiwat
  			    && (com->state & CS_RTS_IFLOW
  				|| tp->t_iflag & IXOFF)
  			    && !(tp->t_state & TS_TBLOCK))
  				ttyblock(tp);
  			tk_nin += incc;
  			tk_rawcc += incc;
  			tp->t_rawcc += incc;
  			com->delta_error_counts[CE_TTY_BUF_OVERFLOW]
  				+= b_to_q((char *)buf, incc, &tp->t_rawq);
  			ttwakeup(tp);
  			if (tp->t_state & TS_TTSTOP
  			    && (tp->t_iflag & IXANY
  				|| tp->t_cc[VSTART] == tp->t_cc[VSTOP])) {
  				tp->t_state &= ~TS_TTSTOP;
  				tp->t_lflag &= ~FLUSHO;
  				comstart(tp);
  			}
  		} else {
  			do {
  				u_char	line_status;
  				int	recv_data;
  
  				line_status = (u_char) buf[CE_INPUT_OFFSET];
  				recv_data = (u_char) *buf++;
  				if (line_status
  				    & (LSR_BI | LSR_FE | LSR_OE | LSR_PE)) {
  					if (line_status & LSR_BI)
  						recv_data |= TTY_BI;
  					if (line_status & LSR_FE)
  						recv_data |= TTY_FE;
  					if (line_status & LSR_OE)
  						recv_data |= TTY_OE;
  					if (line_status & LSR_PE)
  						recv_data |= TTY_PE;
  				}
  				(*linesw[tp->t_line].l_rint)(recv_data, tp);
  			} while (--incc > 0);
  		}
  		if (com_events == 0)
  			break;
  	}
  	if (com_events >= LOTS_OF_EVENTS)
  		goto repeat;
  }
  
  static int
  comparam(tp, t)
  	struct tty	*tp;
  	struct termios	*t;
  {
  	int		bits;
  	int		cflag;
  	struct com_s	*com;
  	u_char		cor_change;
  	u_long		cy_clock;
  	int		idivisor;
  	int		iflag;
  	int		iprescaler;
  	int		itimeout;
  	int		odivisor;
  	int		oprescaler;
  	u_char		opt;
  	int		s;
  	int		unit;
  
  	/* do historical conversions */
  	if (t->c_ispeed == 0)
  		t->c_ispeed = t->c_ospeed;
  
  	unit = DEV_TO_UNIT(tp->t_dev);
  	com = com_addr(unit);
  
  	/* check requested parameters */
  	cy_clock = CY_CLOCK(com->gfrcr_image);
  	idivisor = comspeed(t->c_ispeed, cy_clock, &iprescaler);
  	if (idivisor < 0)
  		return (EINVAL);
  	odivisor = comspeed(t->c_ospeed, cy_clock, &oprescaler);
  	if (odivisor < 0)
  		return (EINVAL);
  
  	/* parameters are OK, convert them to the com struct and the device */
  	s = spltty();
  	if (odivisor == 0)
  		(void)commctl(com, TIOCM_DTR, DMBIC);	/* hang up line */
  	else
  		(void)commctl(com, TIOCM_DTR, DMBIS);
  
  	if (idivisor != 0) {
  		cd_setreg(com, CD1400_RBPR, idivisor);
  		cd_setreg(com, CD1400_RCOR, iprescaler);
  	}
  	if (odivisor != 0) {
  		cd_setreg(com, CD1400_TBPR, odivisor);
  		cd_setreg(com, CD1400_TCOR, oprescaler);
  	}
  
  	/*
  	 * channel control
  	 *	receiver enable
  	 *	transmitter enable (always set)
  	 */
  	cflag = t->c_cflag;
  	opt = CD1400_CCR_CMDCHANCTL | CD1400_CCR_XMTEN
  	      | (cflag & CREAD ? CD1400_CCR_RCVEN : CD1400_CCR_RCVDIS);
  	if (opt != com->channel_control) {
  		com->channel_control = opt;
  		cd1400_channel_cmd(com, opt);
  	}
  
  #ifdef Smarts
  	/* set special chars */
  	/* XXX if one is _POSIX_VDISABLE, can't use some others */
  	if (t->c_cc[VSTOP] != _POSIX_VDISABLE)
  		cd_setreg(com, CD1400_SCHR1, t->c_cc[VSTOP]);
  	if (t->c_cc[VSTART] != _POSIX_VDISABLE)
  		cd_setreg(com, CD1400_SCHR2, t->c_cc[VSTART]);
  	if (t->c_cc[VINTR] != _POSIX_VDISABLE)
  		cd_setreg(com, CD1400_SCHR3, t->c_cc[VINTR]);
  	if (t->c_cc[VSUSP] != _POSIX_VDISABLE)
  		cd_setreg(com, CD1400_SCHR4, t->c_cc[VSUSP]);
  #endif
  
  	/*
  	 * set channel option register 1 -
  	 *	parity mode
  	 *	stop bits
  	 *	char length
  	 */
  	opt = 0;
  	/* parity */
  	if (cflag & PARENB) {
  		if (cflag & PARODD)
  			opt |= CD1400_COR1_PARODD;
  		opt |= CD1400_COR1_PARNORMAL;
  	}
  	iflag = t->c_iflag;
  	if (!(iflag & INPCK))
  		opt |= CD1400_COR1_NOINPCK;
  	bits = 1 + 1;
  	/* stop bits */
  	if (cflag & CSTOPB) {
  		++bits;
  		opt |= CD1400_COR1_STOP2;
  	}
  	/* char length */
  	switch (cflag & CSIZE) {
  	case CS5:
  		bits += 5;
  		opt |= CD1400_COR1_CS5;
  		break;
  	case CS6:
  		bits += 6;
  		opt |= CD1400_COR1_CS6;
  		break;
  	case CS7:
  		bits += 7;
  		opt |= CD1400_COR1_CS7;
  		break;
  	default:
  		bits += 8;
  		opt |= CD1400_COR1_CS8;
  		break;
  	}
  	cor_change = 0;
  	if (opt != com->cor[0]) {
  		cor_change |= CD1400_CCR_COR1;
  		cd_setreg(com, CD1400_COR1, com->cor[0] = opt);
  	}
  
  	/*
  	 * Set receive time-out period, normally to max(one char time, 5 ms).
  	 */
  	if (t->c_ispeed == 0)
  		itimeout = cd_getreg(com, CD1400_RTPR);
  	else {
  		itimeout = (1000 * bits + t->c_ispeed - 1) / t->c_ispeed;
  #ifdef SOFT_HOTCHAR
  #define	MIN_RTP		1
  #else
  #define	MIN_RTP		5
  #endif
  		if (itimeout < MIN_RTP)
  			itimeout = MIN_RTP;
  	}
  	if (!(t->c_lflag & ICANON) && t->c_cc[VMIN] != 0 && t->c_cc[VTIME] != 0
  	    && t->c_cc[VTIME] * 10 > itimeout)
  		itimeout = t->c_cc[VTIME] * 10;
  	if (itimeout > 255)
  		itimeout = 255;
  	cd_setreg(com, CD1400_RTPR, itimeout);
  
  	/*
  	 * set channel option register 2 -
  	 *	flow control
  	 */
  	opt = 0;
  #ifdef Smarts
  	if (iflag & IXANY)
  		opt |= CD1400_COR2_IXANY;
  	if (iflag & IXOFF)
  		opt |= CD1400_COR2_IXOFF;
  #endif
  #ifndef SOFT_CTS_OFLOW
  	if (cflag & CCTS_OFLOW)
  		opt |= CD1400_COR2_CCTS_OFLOW;
  #endif
  	disable_intr();
  	if (opt != com->cor[1]) {
  		cor_change |= CD1400_CCR_COR2;
  		cd_setreg(com, CD1400_COR2, com->cor[1] = opt);
  	}
  	enable_intr();
  
  	/*
  	 * set channel option register 3 -
  	 *	receiver FIFO interrupt threshold
  	 *	flow control
  	 */
  	opt = RxFifoThreshold;
  #ifdef Smarts
  	if (t->c_lflag & ICANON)
  		opt |= CD1400_COR3_SCD34;	/* detect INTR & SUSP chars */
  	if (iflag & IXOFF)
  		/* detect and transparently handle START and STOP chars */
  		opt |= CD1400_COR3_FCT | CD1400_COR3_SCD12;
  #endif
  	if (opt != com->cor[2]) {
  		cor_change |= CD1400_CCR_COR3;
  		cd_setreg(com, CD1400_COR3, com->cor[2] = opt);
  	}
  
  	/* notify the CD1400 if COR1-3 have changed */
  	if (cor_change)
  		cd1400_channel_cmd(com, CD1400_CCR_CMDCORCHG | cor_change);
  
  	/*
  	 * set channel option register 4 -
  	 *	CR/NL processing
  	 *	break processing
  	 *	received exception processing
  	 */
  	opt = 0;
  	if (iflag & IGNCR)
  		opt |= CD1400_COR4_IGNCR;
  #ifdef Smarts
  	/*
  	 * we need a new ttyinput() for this, as we don't want to
  	 * have ICRNL && INLCR being done in both layers, or to have
  	 * synchronisation problems
  	 */
  	if (iflag & ICRNL)
  		opt |= CD1400_COR4_ICRNL;
  	if (iflag & INLCR)
  		opt |= CD1400_COR4_INLCR;
  #endif
  	if (iflag & IGNBRK)
  		opt |= CD1400_COR4_IGNBRK | CD1400_COR4_NOBRKINT;
  	/*
  	 * The `-ignbrk -brkint parmrk' case is not handled by the hardware,
  	 * so only tell the hardware about -brkint if -parmrk.
  	 */
  	if (!(iflag & (BRKINT | PARMRK)))
  		opt |= CD1400_COR4_NOBRKINT;
  #if 0
  	/* XXX using this "intelligence" breaks reporting of overruns. */
  	if (iflag & IGNPAR)
  		opt |= CD1400_COR4_PFO_DISCARD;
  	else {
  		if (iflag & PARMRK)
  			opt |= CD1400_COR4_PFO_ESC;
  		else
  			opt |= CD1400_COR4_PFO_NUL;
  	}
  #else
  	opt |= CD1400_COR4_PFO_EXCEPTION;
  #endif
  	cd_setreg(com, CD1400_COR4, opt);
  
  	/*
  	 * set channel option register 5 -
  	 */
  	opt = 0;
  	if (iflag & ISTRIP)
  		opt |= CD1400_COR5_ISTRIP;
  	if (t->c_iflag & IEXTEN)
  		/* enable LNEXT (e.g. ctrl-v quoting) handling */
  		opt |= CD1400_COR5_LNEXT;
  #ifdef Smarts
  	if (t->c_oflag & ONLCR)
  		opt |= CD1400_COR5_ONLCR;
  	if (t->c_oflag & OCRNL)
  		opt |= CD1400_COR5_OCRNL;
  #endif
  	cd_setreg(com, CD1400_COR5, opt);
  
  	/*
  	 * We always generate modem status change interrupts for CD changes.
  	 * Among other things, this is necessary to track TS_CARR_ON for
  	 * pstat to print even when the driver doesn't care.  CD changes
  	 * should be rare so interrupts for them are not worth extra code to
  	 * avoid.  We avoid interrupts for other modem status changes (except
  	 * for CTS changes when SOFT_CTS_OFLOW is configured) since this is
  	 * simplest and best.
  	 */
  
  	/*
  	 * set modem change option register 1
  	 *	generate modem interrupts on which 1 -> 0 input transitions
  	 *	also controls auto-DTR output flow-control, which we don't use
  	 */
  	opt = CD1400_MCOR1_CDzd;
  #ifdef SOFT_CTS_OFLOW
  	if (cflag & CCTS_OFLOW)
  		opt |= CD1400_MCOR1_CTSzd;
  #endif
  	cd_setreg(com, CD1400_MCOR1, opt);
  
  	/*
  	 * set modem change option register 2
  	 *	generate modem interrupts on specific 0 -> 1 input transitions
  	 */
  	opt = CD1400_MCOR2_CDod;
  #ifdef SOFT_CTS_OFLOW
  	if (cflag & CCTS_OFLOW)
  		opt |= CD1400_MCOR2_CTSod;
  #endif
  	cd_setreg(com, CD1400_MCOR2, opt);
  
  	/*
  	 * XXX should have done this long ago, but there is too much state
  	 * to change all atomically.
  	 */
  	disable_intr();
  
  	com->state &= ~CS_TTGO;
  	if (!(tp->t_state & TS_TTSTOP))
  		com->state |= CS_TTGO;
  	if (cflag & CRTS_IFLOW) {
  		com->state |= CS_RTS_IFLOW;
  		/*
  		 * If CS_RTS_IFLOW just changed from off to on, the change
  		 * needs to be propagated to MCR_RTS.  This isn't urgent,
  		 * so do it later by calling comstart() instead of repeating
  		 * a lot of code from comstart() here.
  		 */
  	} else if (com->state & CS_RTS_IFLOW) {
  		com->state &= ~CS_RTS_IFLOW;
  		/*
  		 * CS_RTS_IFLOW just changed from on to off.  Force MCR_RTS
  		 * on here, since comstart() won't do it later.
  		 */
  #if 0
  		outb(com->modem_ctl_port, com->mcr_image |= MCR_RTS);
  #else
  		cd_setreg(com, com->mcr_rts_reg,
  			  com->mcr_image |= com->mcr_rts);
  #endif
  	}
  
  	/*
  	 * Set up state to handle output flow control.
  	 * XXX - worth handling MDMBUF (DCD) flow control at the lowest level?
  	 * Now has 10+ msec latency, while CTS flow has 50- usec latency.
  	 */
  	com->state |= CS_ODEVREADY;
  #ifdef SOFT_CTS_OFLOW
  	com->state &= ~CS_CTS_OFLOW;
  	if (cflag & CCTS_OFLOW) {
  		com->state |= CS_CTS_OFLOW;
  		if (!(com->last_modem_status & MSR_CTS))
  			com->state &= ~CS_ODEVREADY;
  	}
  #endif
  	/* XXX shouldn't call functions while intrs are disabled. */
  	disc_optim(tp, t, com);
  #if 0
  	/*
  	 * Recover from fiddling with CS_TTGO.  We used to call siointr1()
  	 * unconditionally, but that defeated the careful discarding of
  	 * stale input in sioopen().
  	 */
  	if (com->state >= (CS_BUSY | CS_TTGO))
  		siointr1(com);
  #endif
  	if (com->state >= (CS_BUSY | CS_TTGO | CS_ODEVREADY)) {
  		if (!(com->intr_enable & CD1400_SRER_TXRDY))
  			cd_setreg(com, CD1400_SRER,
  				  com->intr_enable
  				  = com->intr_enable & ~CD1400_SRER_TXMPTY
  				    | CD1400_SRER_TXRDY);
  	} else {
  		if (com->intr_enable & CD1400_SRER_TXRDY)
  			cd_setreg(com, CD1400_SRER,
  				  com->intr_enable
  				  = com->intr_enable & ~CD1400_SRER_TXRDY
  				    | CD1400_SRER_TXMPTY);
  	}
  
  	enable_intr();
  	splx(s);
  	comstart(tp);
  	return (0);
  }
  
  static void
  comstart(tp)
  	struct tty	*tp;
  {
  	struct com_s	*com;
  	int		s;
  #ifdef CyDebug
  	bool_t		started;
  #endif
  	int		unit;
  
  	unit = DEV_TO_UNIT(tp->t_dev);
  	com = com_addr(unit);
  	s = spltty();
  
  #ifdef CyDebug
  	++com->start_count;
  	started = FALSE;
  #endif
  
  	disable_intr();
  	if (tp->t_state & TS_TTSTOP) {
  		com->state &= ~CS_TTGO;
  		if (com->intr_enable & CD1400_SRER_TXRDY)
  			cd_setreg(com, CD1400_SRER,
  				  com->intr_enable
  				  = com->intr_enable & ~CD1400_SRER_TXRDY
  				    | CD1400_SRER_TXMPTY);
  	} else {
  		com->state |= CS_TTGO;
  		if (com->state >= (CS_BUSY | CS_TTGO | CS_ODEVREADY)
  		    && !(com->intr_enable & CD1400_SRER_TXRDY))
  			cd_setreg(com, CD1400_SRER,
  				  com->intr_enable
  				  = com->intr_enable & ~CD1400_SRER_TXMPTY
  				    | CD1400_SRER_TXRDY);
  	}
  	if (tp->t_state & TS_TBLOCK) {
  		if (com->mcr_image & com->mcr_rts && com->state & CS_RTS_IFLOW)
  #if 0
  			outb(com->modem_ctl_port, com->mcr_image &= ~MCR_RTS);
  #else
  			cd_setreg(com, com->mcr_rts_reg,
  				  com->mcr_image &= ~com->mcr_rts);
  #endif
  	} else {
  		if (!(com->mcr_image & com->mcr_rts)
  		    && com->iptr < com->ihighwater
  		    && com->state & CS_RTS_IFLOW)
  #if 0
  			outb(com->modem_ctl_port, com->mcr_image |= MCR_RTS);
  #else
  			cd_setreg(com, com->mcr_rts_reg,
  				  com->mcr_image |= com->mcr_rts);
  #endif
  	}
  	enable_intr();
  	if (tp->t_state & (TS_TIMEOUT | TS_TTSTOP)) {
  		ttwwakeup(tp);
  		splx(s);
  		return;
  	}
  	if (tp->t_outq.c_cc != 0) {
  		struct lbq	*qp;
  		struct lbq	*next;
  
  		if (!com->obufs[0].l_queued) {
  #ifdef CyDebug
  			started = TRUE;
  #endif
  			com->obufs[0].l_tail
  			    = com->obuf1 + q_to_b(&tp->t_outq, com->obuf1,
  						  sizeof com->obuf1);
  			com->obufs[0].l_next = NULL;
  			com->obufs[0].l_queued = TRUE;
  			disable_intr();
  			if (com->state & CS_BUSY) {
  				qp = com->obufq.l_next;
  				while ((next = qp->l_next) != NULL)
  					qp = next;
  				qp->l_next = &com->obufs[0];
  			} else {
  				com->obufq.l_head = com->obufs[0].l_head;
  				com->obufq.l_tail = com->obufs[0].l_tail;
  				com->obufq.l_next = &com->obufs[0];
  				com->state |= CS_BUSY;
  				if (com->state >= (CS_BUSY | CS_TTGO
  						   | CS_ODEVREADY))
  					cd_setreg(com, CD1400_SRER,
  						  com->intr_enable
  						  = com->intr_enable
  						    & ~CD1400_SRER_TXMPTY
  						    | CD1400_SRER_TXRDY);
  			}
  			enable_intr();
  		}
  		if (tp->t_outq.c_cc != 0 && !com->obufs[1].l_queued) {
  #ifdef CyDebug
  			started = TRUE;
  #endif
  			com->obufs[1].l_tail
  			    = com->obuf2 + q_to_b(&tp->t_outq, com->obuf2,
  						  sizeof com->obuf2);
  			com->obufs[1].l_next = NULL;
  			com->obufs[1].l_queued = TRUE;
  			disable_intr();
  			if (com->state & CS_BUSY) {
  				qp = com->obufq.l_next;
  				while ((next = qp->l_next) != NULL)
  					qp = next;
  				qp->l_next = &com->obufs[1];
  			} else {
  				com->obufq.l_head = com->obufs[1].l_head;
  				com->obufq.l_tail = com->obufs[1].l_tail;
  				com->obufq.l_next = &com->obufs[1];
  				com->state |= CS_BUSY;
  				if (com->state >= (CS_BUSY | CS_TTGO
  						   | CS_ODEVREADY))
  					cd_setreg(com, CD1400_SRER,
  						  com->intr_enable
  						  = com->intr_enable
  						    & ~CD1400_SRER_TXMPTY
  						    | CD1400_SRER_TXRDY);
  			}
  			enable_intr();
  		}
  		tp->t_state |= TS_BUSY;
  	}
  #ifdef CyDebug
  	if (started)
  		++com->start_real;
  #endif
  #if 0
  	disable_intr();
  	if (com->state >= (CS_BUSY | CS_TTGO))
  		siointr1(com);	/* fake interrupt to start output */
  	enable_intr();
  #endif
  	ttwwakeup(tp);
  	splx(s);
  }
  
  static void
  siostop(tp, rw)
  	struct tty	*tp;
  	int		rw;
  {
  	struct com_s	*com;
  	bool_t		wakeup_etc;
  
  	com = com_addr(DEV_TO_UNIT(tp->t_dev));
  	wakeup_etc = FALSE;
  	disable_intr();
  	if (rw & FWRITE) {
  		com->obufs[0].l_queued = FALSE;
  		com->obufs[1].l_queued = FALSE;
  		if (com->extra_state & CSE_ODONE) {
  			com_events -= LOTS_OF_EVENTS;
  			com->extra_state &= ~CSE_ODONE;
  			if (com->etc != ETC_NONE) {
  				if (com->etc == ETC_BREAK_ENDED)
  					com->etc = ETC_NONE;
  				wakeup_etc = TRUE;
  			}
  		}
  		com->tp->t_state &= ~TS_BUSY;
  		if (com->state & CS_ODONE)
  			com_events -= LOTS_OF_EVENTS;
  		com->state &= ~(CS_ODONE | CS_BUSY);
  	}
  	if (rw & FREAD) {
  		/* XXX no way to reset only input fifo. */
  		com_events -= (com->iptr - com->ibuf);
  		com->iptr = com->ibuf;
  	}
  	enable_intr();
  	if (wakeup_etc)
  		wakeup(&com->etc);
  	if (rw & FWRITE && com->etc == ETC_NONE)
  		cd1400_channel_cmd(com, CD1400_CCR_CMDRESET | CD1400_CCR_FTF);
  	comstart(tp);
  }
  
  static struct tty *
  siodevtotty(dev)
  	dev_t	dev;
  {
  	int	mynor;
  	int	unit;
  
  	mynor = minor(dev);
  	if (mynor & CONTROL_MASK)
  		return (NULL);
  	unit = MINOR_TO_UNIT(mynor);
  	if ((u_int) unit >= NSIO)
  		return (NULL);
  	return (&sio_tty[unit]);
  }
  
  static int
  commctl(com, bits, how)
  	struct com_s	*com;
  	int		bits;
  	int		how;
  {
  	int	mcr;
  	int	msr;
  
  	if (how == DMGET) {
  		if (com->channel_control & CD1400_CCR_RCVEN)
  			bits |= TIOCM_LE;
  		mcr = com->mcr_image;
  		if (mcr & com->mcr_dtr)
  			bits |= TIOCM_DTR;
  		if (mcr & com->mcr_rts)
  			/* XXX wired on for Cyclom-8Ys */
  			bits |= TIOCM_RTS;
  
  		/*
  		 * We must read the modem status from the hardware because
  		 * we don't generate modem status change interrupts for all
  		 * changes, so com->prev_modem_status is not guaranteed to
  		 * be up to date.  This is safe, unlike for sio, because
  		 * reading the status register doesn't clear pending modem
  		 * status change interrupts.
  		 */
  		msr = cd_getreg(com, CD1400_MSVR2);
  
  		if (msr & MSR_CTS)
  			bits |= TIOCM_CTS;
  		if (msr & MSR_DCD)
  			bits |= TIOCM_CD;
  		if (msr & MSR_DSR)
  			bits |= TIOCM_DSR;
  		if (msr & MSR_RI)
  			/* XXX not connected except for Cyclom-16Y? */
  			bits |= TIOCM_RI;
  		return (bits);
  	}
  	mcr = 0;
  	if (bits & TIOCM_DTR)
  		mcr |= com->mcr_dtr;
  	if (bits & TIOCM_RTS)
  		mcr |= com->mcr_rts;
  	disable_intr();
  	switch (how) {
  	case DMSET:
  		com->mcr_image = mcr;
  		cd_setreg(com, CD1400_MSVR1, mcr);
  		cd_setreg(com, CD1400_MSVR2, mcr);
  		break;
  	case DMBIS:
  		com->mcr_image = mcr = com->mcr_image | mcr;
  		cd_setreg(com, CD1400_MSVR1, mcr);
  		cd_setreg(com, CD1400_MSVR2, mcr);
  		break;
  	case DMBIC:
  		com->mcr_image = mcr = com->mcr_image & ~mcr;
  		cd_setreg(com, CD1400_MSVR1, mcr);
  		cd_setreg(com, CD1400_MSVR2, mcr);
  		break;
  	}
  	enable_intr();
  	return (0);
  }
  
  static void
  siosettimeout()
  {
  	struct com_s	*com;
  	bool_t		someopen;
  	int		unit;
  
  	/*
  	 * Set our timeout period to 1 second if no polled devices are open.
  	 * Otherwise set it to max(1/200, 1/hz).
  	 * Enable timeouts iff some device is open.
  	 */
  	untimeout(comwakeup, (void *)NULL, sio_timeout_handle);
  	sio_timeout = hz;
  	someopen = FALSE;
  	for (unit = 0; unit < NSIO; ++unit) {
  		com = com_addr(unit);
  		if (com != NULL && com->tp != NULL
  		    && com->tp->t_state & TS_ISOPEN) {
  			someopen = TRUE;
  #if 0
  			if (com->poll || com->poll_output) {
  				sio_timeout = hz > 200 ? hz / 200 : 1;
  				break;
  			}
  #endif
  		}
  	}
  	if (someopen) {
  		sio_timeouts_until_log = hz / sio_timeout;
  		sio_timeout_handle = timeout(comwakeup, (void *)NULL,
  					     sio_timeout);
  	} else {
  		/* Flush error messages, if any. */
  		sio_timeouts_until_log = 1;
  		comwakeup((void *)NULL);
  		untimeout(comwakeup, (void *)NULL, sio_timeout_handle);
  	}
  }
  
  static void
  comwakeup(chan)
  	void	*chan;
  {
  	struct com_s	*com;
  	int		unit;
  
  	sio_timeout_handle = timeout(comwakeup, (void *)NULL, sio_timeout);
  
  #if 0
  	/*
  	 * Recover from lost output interrupts.
  	 * Poll any lines that don't use interrupts.
  	 */
  	for (unit = 0; unit < NSIO; ++unit) {
  		com = com_addr(unit);
  		if (com != NULL
  		    && (com->state >= (CS_BUSY | CS_TTGO) || com->poll)) {
  			disable_intr();
  			siointr1(com);
  			enable_intr();
  		}
  	}
  #endif
  
  	/*
  	 * Check for and log errors, but not too often.
  	 */
  	if (--sio_timeouts_until_log > 0)
  		return;
  	sio_timeouts_until_log = hz / sio_timeout;
  	for (unit = 0; unit < NSIO; ++unit) {
  		int	errnum;
  
  		com = com_addr(unit);
  		if (com == NULL)
  			continue;
  		for (errnum = 0; errnum < CE_NTYPES; ++errnum) {
  			u_int	delta;
  			u_long	total;
  
  			disable_intr();
  			delta = com->delta_error_counts[errnum];
  			com->delta_error_counts[errnum] = 0;
  			enable_intr();
  			if (delta == 0)
  				continue;
  			total = com->error_counts[errnum] += delta;
  			log(LOG_ERR, "cy%d: %u more %s%s (total %lu)\n",
  			    unit, delta, error_desc[errnum],
  			    delta == 1 ? "" : "s", total);
  		}
  	}
  }
  
  static void
  disc_optim(tp, t, com)
  	struct tty	*tp;
  	struct termios	*t;
  	struct com_s	*com;
  {
  #ifndef SOFT_HOTCHAR
  	u_char	opt;
  #endif
  
  	/*
  	 * XXX can skip a lot more cases if Smarts.  Maybe
  	 * (IGNCR | ISTRIP | IXON) in c_iflag.  But perhaps we
  	 * shouldn't skip if (TS_CNTTB | TS_LNCH) is set in t_state.
  	 */
  	if (!(t->c_iflag & (ICRNL | IGNCR | IMAXBEL | INLCR | ISTRIP | IXON))
  	    && (!(t->c_iflag & BRKINT) || (t->c_iflag & IGNBRK))
  	    && (!(t->c_iflag & PARMRK)
  		|| (t->c_iflag & (IGNPAR | IGNBRK)) == (IGNPAR | IGNBRK))
  	    && !(t->c_lflag & (ECHO | ICANON | IEXTEN | ISIG | PENDIN))
  	    && linesw[tp->t_line].l_rint == ttyinput)
  		tp->t_state |= TS_CAN_BYPASS_L_RINT;
  	else
  		tp->t_state &= ~TS_CAN_BYPASS_L_RINT;
  	com->hotchar = linesw[tp->t_line].l_hotchar;
  #ifndef SOFT_HOTCHAR
  	opt = com->cor[2] & ~CD1400_COR3_SCD34;
  	if (com->hotchar != 0) {
  		cd_setreg(com, CD1400_SCHR3, com->hotchar);
  		cd_setreg(com, CD1400_SCHR4, com->hotchar);
  		opt |= CD1400_COR3_SCD34;
  	}
  	if (opt != com->cor[2]) {
  		cd_setreg(com, CD1400_COR3, com->cor[2] = opt);
  		cd1400_channel_cmd(com, CD1400_CCR_CMDCORCHG | CD1400_CCR_COR3);
  	}
  #endif
  }
  
  #ifdef Smarts
  /* standard line discipline input routine */
  int
  cyinput(c, tp)
  	int		c;
  	struct tty	*tp;
  {
  	/* XXX duplicate ttyinput(), but without the IXOFF/IXON/ISTRIP/IPARMRK
  	 * bits, as they are done by the CD1400.  Hardly worth the effort,
  	 * given that high-throughput sessions are raw anyhow.
  	 */
  }
  #endif /* Smarts */
  
  static int
  comspeed(speed, cy_clock, prescaler_io)
  	speed_t	speed;
  	u_long	cy_clock;
  	int	*prescaler_io;
  {
  	int	actual;
  	int	error;
  	int	divider;
  	int	prescaler;
  	int	prescaler_unit;
  
  	if (speed == 0)
  		return (0);
  	if (speed < 0 || speed > 150000)
  		return (-1);
  
  	/* determine which prescaler to use */
  	for (prescaler_unit = 4, prescaler = 2048; prescaler_unit;
  		prescaler_unit--, prescaler >>= 2) {
  		if (cy_clock / prescaler / speed > 63)
  			break;
  	}
  
  	divider = (cy_clock / prescaler * 2 / speed + 1) / 2; /* round off */
  	if (divider > 255)
  		divider = 255;
  	actual = cy_clock/prescaler/divider;
  
  	/* 10 times error in percent: */
  	error = ((actual - (long)speed) * 2000 / (long)speed + 1) / 2;
  
  	/* 3.0% max error tolerance */
  	if (error < -30 || error > 30)
  		return (-1);
  
  #if 0
  	printf("prescaler = %d (%d)\n", prescaler, prescaler_unit);
  	printf("divider = %d (%x)\n", divider, divider);
  	printf("actual = %d\n", actual);
  	printf("error = %d\n", error);
  #endif
  
  	*prescaler_io = prescaler_unit;
  	return (divider);
  }
  
  static void
  cd1400_channel_cmd(com, cmd)
  	struct com_s	*com;
  	int		cmd;
  {
  	cd1400_channel_cmd_wait(com);
  	cd_setreg(com, CD1400_CCR, cmd);
  	cd1400_channel_cmd_wait(com);
  }
  
  static void
  cd1400_channel_cmd_wait(com)
  	struct com_s	*com;
  {
  	struct timeval	start;
  	struct timeval	tv;
  	long		usec;
  
  	if (cd_getreg(com, CD1400_CCR) == 0)
  		return;
  	microtime(&start);
  	for (;;) {
  		if (cd_getreg(com, CD1400_CCR) == 0)
  			return;
  		microtime(&tv);
  		usec = 1000000 * (tv.tv_sec - start.tv_sec) +
  		    tv.tv_usec - start.tv_usec;
  		if (usec >= 5000) {
  			log(LOG_ERR,
  			    "cy%d: channel command timeout (%ld usec)\n",
  			    com->unit, usec);
  			return;
  		}
  	}
  }
  
  static void
  cd_etc(com, etc)
  	struct com_s	*com;
  	int		etc;
  {
  	/*
  	 * We can't change the hardware's ETC state while there are any
  	 * characters in the tx fifo, since those characters would be
  	 * interpreted as commands!  Unputting characters from the fifo
  	 * is difficult, so we wait up to 12 character times for the fifo
  	 * to drain.  The command will be delayed for up to 2 character
  	 * times for the tx to become empty.  Unputting characters from
  	 * the tx holding and shift registers is impossible, so we wait
  	 * for the tx to become empty so that the command is sure to be
  	 * executed soon after we issue it.
  	 */
  	disable_intr();
  	if (com->etc == etc) {
  		enable_intr();
  		goto wait;
  	}
  	if (etc == CD1400_ETC_SENDBREAK
  	    && (com->etc == ETC_BREAK_STARTING
  		|| com->etc == ETC_BREAK_STARTED)
  	    || etc == CD1400_ETC_STOPBREAK
  	       && (com->etc == ETC_BREAK_ENDING || com->etc == ETC_BREAK_ENDED
  		   || com->etc == ETC_NONE)) {
  		enable_intr();
  		return;
  	}
  	com->etc = etc;
  	cd_setreg(com, CD1400_SRER,
  		  com->intr_enable
  		  = com->intr_enable & ~CD1400_SRER_TXRDY | CD1400_SRER_TXMPTY);
  	enable_intr();
  wait:
  	while (com->etc == etc
  	       && tsleep(&com->etc, TTIPRI | PCATCH, "cyetc", 0) == 0)
  		continue;
  }
  
  static int
  cd_getreg(com, reg)
  	struct com_s	*com;
  	int		reg;
  {
  	struct com_s	*basecom;
  	u_char	car;
  	int	cy_align;
  	u_long	ef;
  	cy_addr	iobase;
  	int	val;
  
  	basecom = com_addr(com->unit & ~(CD1400_NO_OF_CHANNELS - 1));
  	car = com->unit & CD1400_CAR_CHAN;
  	cy_align = com->cy_align;
  	iobase = com->iobase;
  	ef = read_eflags();
  	disable_intr();
  	if (basecom->car != car)
  		cd_outb(iobase, CD1400_CAR, cy_align, basecom->car = car);
  	val = cd_inb(iobase, reg, cy_align);
  	write_eflags(ef);
  	return (val);
  }
  
  static void
  cd_setreg(com, reg, val)
  	struct com_s	*com;
  	int		reg;
  	int		val;
  {
  	struct com_s	*basecom;
  	u_char	car;
  	int	cy_align;
  	u_long	ef;
  	cy_addr	iobase;
  
  	basecom = com_addr(com->unit & ~(CD1400_NO_OF_CHANNELS - 1));
  	car = com->unit & CD1400_CAR_CHAN;
  	cy_align = com->cy_align;
  	iobase = com->iobase;
  	ef = read_eflags();
  	disable_intr();
  	if (basecom->car != car)
  		cd_outb(iobase, CD1400_CAR, cy_align, basecom->car = car);
  	cd_outb(iobase, reg, cy_align, val);
  	write_eflags(ef);
  }
  
  #ifdef CyDebug
  /* useful in ddb */
  void
  cystatus(unit)
  	int	unit;
  {
  	struct com_s	*com;
  	cy_addr		iobase;
  	u_int		ocount;
  	struct tty	*tp;
  
  	com = com_addr(unit);
  	printf("info for channel %d\n", unit);
  	printf("------------------\n");
  	printf("total cyclom service probes:\t%d\n", cy_svrr_probes);
  	printf("calls to upper layer:\t\t%d\n", cy_timeouts);
  	if (com == NULL)
  		return;
  	iobase = com->iobase;
  	printf("\n");
  	printf("cd1400 base address:\\tt%p\n", iobase);
  	printf("saved channel_control:\t\t0x%02x\n", com->channel_control);
  	printf("saved cor1-3:\t\t\t0x%02x 0x%02x 0x%02x\n",
  	       com->cor[0], com->cor[1], com->cor[2]);
  	printf("service request enable reg:\t0x%02x (0x%02x cached)\n",
  	       cd_getreg(com, CD1400_SRER), com->intr_enable);
  	printf("service request register:\t0x%02x\n",
  	       cd_inb(iobase, CD1400_SVRR, com->cy_align));
  	printf("modem status:\t\t\t0x%02x (0x%02x cached)\n",
  	       cd_getreg(com, CD1400_MSVR2), com->prev_modem_status);
  	printf("rx/tx/mdm interrupt registers:\t0x%02x 0x%02x 0x%02x\n",
  	       cd_inb(iobase, CD1400_RIR, com->cy_align),
  	       cd_inb(iobase, CD1400_TIR, com->cy_align),
  	       cd_inb(iobase, CD1400_MIR, com->cy_align));
  	printf("\n");
  	printf("com state:\t\t\t0x%02x\n", com->state);
  	printf("calls to comstart():\t\t%d (%d useful)\n",
  	       com->start_count, com->start_real);
  	printf("rx buffer chars free:\t\t%d\n", com->iptr - com->ibuf);
  	ocount = 0;
  	if (com->obufs[0].l_queued)
  		ocount += com->obufs[0].l_tail - com->obufs[0].l_head;
  	if (com->obufs[1].l_queued)
  		ocount += com->obufs[1].l_tail - com->obufs[1].l_head;
  	printf("tx buffer chars:\t\t%u\n", ocount);
  	printf("received chars:\t\t\t%d\n", com->bytes_in);
  	printf("received exceptions:\t\t%d\n", com->recv_exception);
  	printf("modem signal deltas:\t\t%d\n", com->mdm);
  	printf("transmitted chars:\t\t%d\n", com->bytes_out);
  	printf("\n");
  	tp = com->tp;
  	if (tp != NULL) {
  		printf("tty state:\t\t\t0x%08x\n", tp->t_state);
  		printf(
  		"upper layer queue lengths:\t%d raw, %d canon, %d output\n",
  		       tp->t_rawq.c_cc, tp->t_canq.c_cc, tp->t_outq.c_cc);
  	} else
  		printf("tty state:\t\t\tclosed\n");
  }
  #endif /* CyDebug */
  