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com.c revision 1.1
      1 /*-
      2  * Copyright (c) 1991 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  *
     33  *	@(#)com.c	7.5 (Berkeley) 5/16/91
     34  */
     35 static char rcsid[] = "$Header: /tank/opengrok/rsync2/NetBSD/src/sys/dev/ic/com.c,v 1.1 1993/03/21 09:45:37 cgd Exp $";
     36 
     37 #include "com.h"
     38 #if NCOM > 0
     39 /*
     40  * COM driver, based on HP dca driver
     41  * uses National Semiconductor NS16450/NS16550AF UART
     42  */
     43 #include "param.h"
     44 #include "systm.h"
     45 #include "ioctl.h"
     46 #include "tty.h"
     47 #include "proc.h"
     48 #include "user.h"
     49 #include "conf.h"
     50 #include "file.h"
     51 #include "uio.h"
     52 #include "kernel.h"
     53 #include "syslog.h"
     54 
     55 #include "i386/isa/isa_device.h"
     56 #include "i386/isa/comreg.h"
     57 #include "i386/isa/ic/ns16550.h"
     58 #define cominor(d)
     59 
     60 int 	comprobe(), comattach(), comintr(), comstart(), comparam();
     61 
     62 struct	isa_driver comdriver = {
     63 	comprobe, comattach, "com"
     64 };
     65 
     66 int	comsoftCAR;
     67 int	com_active;
     68 int	com_hasfifo;
     69 int	ncom = NCOM;
     70 #ifdef COMCONSOLE
     71 int	comconsole = COMCONSOLE;
     72 #else
     73 int	comconsole = -1;
     74 #endif
     75 int	comconsinit;
     76 int	comdefaultrate = TTYDEF_SPEED;
     77 int	commajor;
     78 short com_addr[NCOM];
     79 struct	tty com_tty[NCOM];
     80 
     81 struct speedtab comspeedtab[] = {
     82 	0,	0,
     83 	50,	COMBRD(50),
     84 	75,	COMBRD(75),
     85 	110,	COMBRD(110),
     86 	134,	COMBRD(134),
     87 	150,	COMBRD(150),
     88 	200,	COMBRD(200),
     89 	300,	COMBRD(300),
     90 	600,	COMBRD(600),
     91 	1200,	COMBRD(1200),
     92 	1800,	COMBRD(1800),
     93 	2400,	COMBRD(2400),
     94 	4800,	COMBRD(4800),
     95 	9600,	COMBRD(9600),
     96 	19200,	COMBRD(19200),
     97 	38400,	COMBRD(38400),
     98 	57600,	COMBRD(57600),
     99 	-1,	-1
    100 };
    101 
    102 extern	struct tty *constty;
    103 #ifdef KGDB
    104 #include "machine/remote-sl.h"
    105 
    106 extern int kgdb_dev;
    107 extern int kgdb_rate;
    108 extern int kgdb_debug_init;
    109 #endif
    110 
    111 #define	UNIT(x)		(minor(x)-1)
    112 
    113 comprobe(dev)
    114 struct isa_device *dev;
    115 {
    116 	/* force access to id reg */
    117 	outb(dev->id_iobase+com_cfcr, 0);
    118 	outb(dev->id_iobase+com_iir, 0);
    119 	DELAY(100);
    120 	if ((inb(dev->id_iobase+com_iir) & 0x38) == 0)
    121 		return(1);
    122 	return(0);
    123 }
    124 
    125 
    126 int
    127 comattach(isdp)
    128 struct isa_device *isdp;
    129 {
    130 	struct	tty	*tp;
    131 	u_char		unit;
    132 	int		port = isdp->id_iobase;
    133 
    134 	unit = isdp->id_unit - 1;
    135 	if (unit == comconsole)
    136 		DELAY(1000);
    137 	com_addr[unit] = port;
    138 	com_active |= 1 << unit;
    139 	comsoftCAR |= 1 << unit;	/* XXX */
    140 
    141 	/* look for a NS 16550AF UART with FIFOs */
    142 	outb(port+com_fifo, FIFO_ENABLE|FIFO_RCV_RST|FIFO_XMT_RST|FIFO_TRIGGER_14);
    143 	DELAY(100);
    144 	if ((inb(port+com_iir) & IIR_FIFO_MASK) == IIR_FIFO_MASK) {
    145 		com_hasfifo |= 1 << unit;
    146 		printf(" fifo");
    147 	}
    148 
    149 	outb(port+com_ier, 0);
    150 	outb(port+com_mcr, 0 | MCR_IENABLE);
    151 #ifdef KGDB
    152 	if (kgdb_dev == makedev(commajor, unit+1)) {
    153 		if (comconsole == unit)
    154 			kgdb_dev = -1;	/* can't debug over console port */
    155 		else {
    156 			(void) cominit(unit, kgdb_rate);
    157 			if (kgdb_debug_init) {
    158 				/*
    159 				 * Print prefix of device name,
    160 				 * let kgdb_connect print the rest.
    161 				 */
    162 				printf("com%d: ", unit);
    163 				kgdb_connect(1);
    164 			} else
    165 				printf("com%d: kgdb enabled\n", unit);
    166 		}
    167 	}
    168 #endif
    169 	/*
    170 	 * Need to reset baud rate, etc. of next print so reset comconsinit.
    171 	 * Also make sure console is always "hardwired"
    172 	 */
    173 	if (unit == comconsole) {
    174 		comconsinit = 0;
    175 		comsoftCAR |= (1 << unit);
    176 	}
    177 	return (1);
    178 }
    179 
    180 /* ARGSUSED */
    181 comopen(dev_t dev, int flag, int mode, struct proc *p)
    182 {
    183 	register struct tty *tp;
    184 	register int unit;
    185 	int error = 0;
    186 
    187 	unit = UNIT(dev);
    188 	if (unit >= NCOM || (com_active & (1 << unit)) == 0)
    189 		return (ENXIO);
    190 	tp = &com_tty[unit];
    191 	tp->t_oproc = comstart;
    192 	tp->t_param = comparam;
    193 	tp->t_dev = dev;
    194 	if ((tp->t_state & TS_ISOPEN) == 0) {
    195 		tp->t_state |= TS_WOPEN;
    196 		ttychars(tp);
    197 		if (tp->t_ispeed == 0) {
    198 			tp->t_iflag = TTYDEF_IFLAG;
    199 			tp->t_oflag = TTYDEF_OFLAG;
    200 			tp->t_cflag = TTYDEF_CFLAG;
    201 			tp->t_lflag = TTYDEF_LFLAG;
    202 			tp->t_ispeed = tp->t_ospeed = comdefaultrate;
    203 		}
    204 		comparam(tp, &tp->t_termios);
    205 		ttsetwater(tp);
    206 	} else if (tp->t_state&TS_XCLUDE && p->p_ucred->cr_uid != 0)
    207 		return (EBUSY);
    208 	(void) spltty();
    209 	(void) commctl(dev, MCR_DTR | MCR_RTS, DMSET);
    210 	if ((comsoftCAR & (1 << unit)) || (commctl(dev, 0, DMGET) & MSR_DCD))
    211 		tp->t_state |= TS_CARR_ON;
    212 	while ((flag&O_NONBLOCK) == 0 && (tp->t_cflag&CLOCAL) == 0 &&
    213 	       (tp->t_state & TS_CARR_ON) == 0) {
    214 		tp->t_state |= TS_WOPEN;
    215 		if (error = ttysleep(tp, (caddr_t)&tp->t_raw, TTIPRI | PCATCH,
    216 		    ttopen, 0))
    217 			break;
    218 	}
    219 	(void) spl0();
    220 	if (error == 0)
    221 		error = (*linesw[tp->t_line].l_open)(dev, tp);
    222 	return (error);
    223 }
    224 
    225 /*ARGSUSED*/
    226 comclose(dev, flag, mode, p)
    227 	dev_t dev;
    228 	int flag, mode;
    229 	struct proc *p;
    230 {
    231 	register struct tty *tp;
    232 	register com;
    233 	register int unit;
    234 
    235 	unit = UNIT(dev);
    236 	com = com_addr[unit];
    237 	tp = &com_tty[unit];
    238 	(*linesw[tp->t_line].l_close)(tp, flag);
    239 	outb(com+com_cfcr, inb(com+com_cfcr) & ~CFCR_SBREAK);
    240 #ifdef KGDB
    241 	/* do not disable interrupts if debugging */
    242 	if (kgdb_dev != makedev(commajor, unit+1))
    243 #endif
    244 	outb(com+com_ier, 0);
    245 	if (tp->t_cflag&HUPCL || tp->t_state&TS_WOPEN ||
    246 	    (tp->t_state&TS_ISOPEN) == 0)
    247 		(void) commctl(dev, 0, DMSET);
    248 	ttyclose(tp);
    249 	return(0);
    250 }
    251 
    252 comread(dev, uio, flag)
    253 	dev_t dev;
    254 	struct uio *uio;
    255 {
    256 	register struct tty *tp = &com_tty[UNIT(dev)];
    257 
    258 	return ((*linesw[tp->t_line].l_read)(tp, uio, flag));
    259 }
    260 
    261 comwrite(dev, uio, flag)
    262 	dev_t dev;
    263 	struct uio *uio;
    264 {
    265 	int unit = UNIT(dev);
    266 	register struct tty *tp = &com_tty[unit];
    267 
    268 	/*
    269 	 * (XXX) We disallow virtual consoles if the physical console is
    270 	 * a serial port.  This is in case there is a display attached that
    271 	 * is not the console.  In that situation we don't need/want the X
    272 	 * server taking over the console.
    273 	 */
    274 	if (constty && unit == comconsole)
    275 		constty = NULL;
    276 	return ((*linesw[tp->t_line].l_write)(tp, uio, flag));
    277 }
    278 
    279 comintr(unit)
    280 	register int unit;
    281 {
    282 	register com;
    283 	register u_char code;
    284 	register struct tty *tp;
    285 
    286 	unit--;
    287 	com = com_addr[unit];
    288 	while (1) {
    289 		code = inb(com+com_iir);
    290 		switch (code & IIR_IMASK) {
    291 		case IIR_NOPEND:
    292 			return (1);
    293 		case IIR_RXTOUT:
    294 		case IIR_RXRDY:
    295 			tp = &com_tty[unit];
    296 /*
    297  * Process received bytes.  Inline for speed...
    298  */
    299 #ifdef KGDB
    300 #define	RCVBYTE() \
    301 			code = inb(com+com_data); \
    302 			if ((tp->t_state & TS_ISOPEN) == 0) { \
    303 				if (kgdb_dev == makedev(commajor, unit+1) && \
    304 				    code == FRAME_END) \
    305 					kgdb_connect(0); /* trap into kgdb */ \
    306 			} else \
    307 				(*linesw[tp->t_line].l_rint)(code, tp)
    308 #else
    309 #define	RCVBYTE() \
    310 			code = inb(com+com_data); \
    311 			if (tp->t_state & TS_ISOPEN) \
    312 				(*linesw[tp->t_line].l_rint)(code, tp)
    313 #endif
    314 
    315 			RCVBYTE();
    316 
    317 			if (com_hasfifo & (1 << unit))
    318 				while ((code = inb(com+com_lsr)) & LSR_RCV_MASK) {
    319 					if (code == LSR_RXRDY) {
    320 						RCVBYTE();
    321 					} else
    322 						comeint(unit, code, com);
    323 				}
    324 			break;
    325 		case IIR_TXRDY:
    326 			tp = &com_tty[unit];
    327 			tp->t_state &=~ (TS_BUSY|TS_FLUSH);
    328 			if (tp->t_line)
    329 				(*linesw[tp->t_line].l_start)(tp);
    330 			else
    331 				comstart(tp);
    332 			break;
    333 		case IIR_RLS:
    334 			comeint(unit, inb(com+com_lsr), com);
    335 			break;
    336 		default:
    337 			if (code & IIR_NOPEND)
    338 				return (1);
    339 			log(LOG_WARNING, "com%d: weird interrupt: 0x%x\n",
    340 			    unit, code);
    341 			/* fall through */
    342 		case IIR_MLSC:
    343 			commint(unit, com);
    344 			break;
    345 		}
    346 	}
    347 }
    348 
    349 comeint(unit, stat, com)
    350 	register int unit, stat;
    351 	register com;
    352 {
    353 	register struct tty *tp;
    354 	register int c;
    355 
    356 	tp = &com_tty[unit];
    357 	c = inb(com+com_data);
    358 	if ((tp->t_state & TS_ISOPEN) == 0) {
    359 #ifdef KGDB
    360 		/* we don't care about parity errors */
    361 		if (((stat & (LSR_BI|LSR_FE|LSR_PE)) == LSR_PE) &&
    362 		    kgdb_dev == makedev(commajor, unit+1) && c == FRAME_END)
    363 			kgdb_connect(0); /* trap into kgdb */
    364 #endif
    365 		return;
    366 	}
    367 	if (stat & (LSR_BI | LSR_FE))
    368 		c |= TTY_FE;
    369 	else if (stat & LSR_PE)
    370 		c |= TTY_PE;
    371 	else if (stat & LSR_OE)
    372 		log(LOG_WARNING, "com%d: silo overflow\n", unit);
    373 	(*linesw[tp->t_line].l_rint)(c, tp);
    374 }
    375 
    376 commint(unit, com)
    377 	register int unit;
    378 	register com;
    379 {
    380 	register struct tty *tp;
    381 	register int stat;
    382 
    383 	tp = &com_tty[unit];
    384 	stat = inb(com+com_msr);
    385 	if ((stat & MSR_DDCD) && (comsoftCAR & (1 << unit)) == 0) {
    386 		if (stat & MSR_DCD)
    387 			(void)(*linesw[tp->t_line].l_modem)(tp, 1);
    388 		else if ((*linesw[tp->t_line].l_modem)(tp, 0) == 0)
    389 			outb(com+com_mcr,
    390 				inb(com+com_mcr) & ~(MCR_DTR | MCR_RTS) | MCR_IENABLE);
    391 	} else if ((stat & MSR_DCTS) && (tp->t_state & TS_ISOPEN) &&
    392 		   (tp->t_flags & CRTSCTS)) {
    393 		/* the line is up and we want to do rts/cts flow control */
    394 		if (stat & MSR_CTS) {
    395 			tp->t_state &=~ TS_TTSTOP;
    396 			ttstart(tp);
    397 		} else
    398 			tp->t_state |= TS_TTSTOP;
    399 	}
    400 }
    401 
    402 comioctl(dev, cmd, data, flag)
    403 	dev_t dev;
    404 	caddr_t data;
    405 {
    406 	register struct tty *tp;
    407 	register int unit = UNIT(dev);
    408 	register com;
    409 	register int error;
    410 
    411 	tp = &com_tty[unit];
    412 	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag);
    413 	if (error >= 0)
    414 		return (error);
    415 	error = ttioctl(tp, cmd, data, flag);
    416 	if (error >= 0)
    417 		return (error);
    418 
    419 	com = com_addr[unit];
    420 	switch (cmd) {
    421 
    422 	case TIOCSBRK:
    423 		outb(com+com_cfcr, inb(com+com_cfcr) | CFCR_SBREAK);
    424 		break;
    425 
    426 	case TIOCCBRK:
    427 		outb(com+com_cfcr, inb(com+com_cfcr) & ~CFCR_SBREAK);
    428 		break;
    429 
    430 	case TIOCSDTR:
    431 		(void) commctl(dev, MCR_DTR | MCR_RTS, DMBIS);
    432 		break;
    433 
    434 	case TIOCCDTR:
    435 		(void) commctl(dev, MCR_DTR | MCR_RTS, DMBIC);
    436 		break;
    437 
    438 	case TIOCMSET:
    439 		(void) commctl(dev, *(int *)data, DMSET);
    440 		break;
    441 
    442 	case TIOCMBIS:
    443 		(void) commctl(dev, *(int *)data, DMBIS);
    444 		break;
    445 
    446 	case TIOCMBIC:
    447 		(void) commctl(dev, *(int *)data, DMBIC);
    448 		break;
    449 
    450 	case TIOCMGET:
    451 		*(int *)data = commctl(dev, 0, DMGET);
    452 		break;
    453 
    454 	default:
    455 		return (ENOTTY);
    456 	}
    457 	return (0);
    458 }
    459 
    460 comparam(tp, t)
    461 	register struct tty *tp;
    462 	register struct termios *t;
    463 {
    464 	register com;
    465 	register int cfcr, cflag = t->c_cflag;
    466 	int unit = UNIT(tp->t_dev);
    467 	int ospeed = ttspeedtab(t->c_ospeed, comspeedtab);
    468 
    469 	/* check requested parameters */
    470         if (ospeed < 0 || (t->c_ispeed && t->c_ispeed != t->c_ospeed))
    471                 return(EINVAL);
    472         /* and copy to tty */
    473         tp->t_ispeed = t->c_ispeed;
    474         tp->t_ospeed = t->c_ospeed;
    475         tp->t_cflag = cflag;
    476 
    477 	com = com_addr[unit];
    478 	outb(com+com_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS /*| IER_EMSC*/);
    479 	if (ospeed == 0) {
    480 		(void) commctl(unit, 0, DMSET);	/* hang up line */
    481 		return(0);
    482 	}
    483 	outb(com+com_cfcr, inb(com+com_cfcr) | CFCR_DLAB);
    484 	outb(com+com_data, ospeed & 0xFF);
    485 	outb(com+com_ier, ospeed >> 8);
    486 	switch (cflag&CSIZE) {
    487 	case CS5:
    488 		cfcr = CFCR_5BITS; break;
    489 	case CS6:
    490 		cfcr = CFCR_6BITS; break;
    491 	case CS7:
    492 		cfcr = CFCR_7BITS; break;
    493 	case CS8:
    494 		cfcr = CFCR_8BITS; break;
    495 	}
    496 	if (cflag&PARENB) {
    497 		cfcr |= CFCR_PENAB;
    498 		if ((cflag&PARODD) == 0)
    499 			cfcr |= CFCR_PEVEN;
    500 	}
    501 	if (cflag&CSTOPB)
    502 		cfcr |= CFCR_STOPB;
    503 	outb(com+com_cfcr, cfcr);
    504 
    505 	if (com_hasfifo & (1 << unit))
    506 		outb(com+com_fifo, FIFO_ENABLE | FIFO_TRIGGER_14);
    507 
    508 	return(0);
    509 }
    510 
    511 comstart(tp)
    512 	register struct tty *tp;
    513 {
    514 	register com;
    515 	int s, unit, c;
    516 
    517 	unit = UNIT(tp->t_dev);
    518 	com = com_addr[unit];
    519 	s = spltty();
    520 	if (tp->t_state & (TS_TIMEOUT|TS_TTSTOP))
    521 		goto out;
    522 	if (RB_LEN(&tp->t_out) <= tp->t_lowat) {
    523 		if (tp->t_state&TS_ASLEEP) {
    524 			tp->t_state &= ~TS_ASLEEP;
    525 			wakeup((caddr_t)&tp->t_out);
    526 		}
    527 		if (tp->t_wsel) {
    528 			selwakeup(tp->t_wsel, tp->t_state & TS_WCOLL);
    529 			tp->t_wsel = 0;
    530 			tp->t_state &= ~TS_WCOLL;
    531 		}
    532 	}
    533 	if (RB_LEN(&tp->t_out) == 0)
    534 		goto out;
    535 	if (inb(com+com_lsr) & LSR_TXRDY) {
    536 		c = getc(&tp->t_out);
    537 		tp->t_state |= TS_BUSY;
    538 		outb(com+com_data, c);
    539 		if (com_hasfifo & (1 << unit))
    540 			for (c = 1; c < 16 && RB_LEN(&tp->t_out); ++c)
    541 				outb(com+com_data, getc(&tp->t_out));
    542 	}
    543 out:
    544 	splx(s);
    545 }
    546 
    547 /*
    548  * Stop output on a line.
    549  */
    550 /*ARGSUSED*/
    551 comstop(tp, flag)
    552 	register struct tty *tp;
    553 {
    554 	register int s;
    555 
    556 	s = spltty();
    557 	if (tp->t_state & TS_BUSY) {
    558 		if ((tp->t_state&TS_TTSTOP)==0)
    559 			tp->t_state |= TS_FLUSH;
    560 	}
    561 	splx(s);
    562 }
    563 
    564 commctl(dev, bits, how)
    565 	dev_t dev;
    566 	int bits, how;
    567 {
    568 	register com;
    569 	register int unit;
    570 	int s;
    571 
    572 	unit = UNIT(dev);
    573 	com = com_addr[unit];
    574 	s = spltty();
    575 	switch (how) {
    576 
    577 	case DMSET:
    578 		outb(com+com_mcr, bits | MCR_IENABLE);
    579 		break;
    580 
    581 	case DMBIS:
    582 		outb(com+com_mcr, inb(com+com_mcr) | bits | MCR_IENABLE);
    583 		break;
    584 
    585 	case DMBIC:
    586 		outb(com+com_mcr, inb(com+com_mcr) & ~bits | MCR_IENABLE);
    587 		break;
    588 
    589 	case DMGET:
    590 		bits = inb(com+com_msr);
    591 		break;
    592 	}
    593 	(void) splx(s);
    594 	return(bits);
    595 }
    596 
    597 /*
    598  * Following are all routines needed for COM to act as console
    599  */
    600 #include "i386/i386/cons.h"
    601 
    602 comcnprobe(cp)
    603 	struct consdev *cp;
    604 {
    605 	int unit;
    606 
    607 	/* locate the major number */
    608 	for (commajor = 0; commajor < nchrdev; commajor++)
    609 		if (cdevsw[commajor].d_open == comopen)
    610 			break;
    611 
    612 	/* XXX: ick */
    613 	unit = CONUNIT;
    614 	com_addr[CONUNIT] = CONADDR;
    615 
    616 	/* make sure hardware exists?  XXX */
    617 
    618 	/* initialize required fields */
    619 	cp->cn_dev = makedev(commajor, unit+1);
    620 	cp->cn_tp = &com_tty[unit];
    621 #ifdef	COMCONSOLE
    622 	cp->cn_pri = CN_REMOTE;		/* Force a serial port console */
    623 #else
    624 	cp->cn_pri = CN_NORMAL;
    625 #endif
    626 }
    627 
    628 comcninit(cp)
    629 	struct consdev *cp;
    630 {
    631 	int unit = UNIT(cp->cn_dev);
    632 
    633 	cominit(unit, comdefaultrate);
    634 	comconsole = unit;
    635 	comconsinit = 1;
    636 }
    637 
    638 cominit(unit, rate)
    639 	int unit, rate;
    640 {
    641 	register int com;
    642 	int s;
    643 	short stat;
    644 
    645 #ifdef lint
    646 	stat = unit; if (stat) return;
    647 #endif
    648 	com = com_addr[unit];
    649 	s = splhigh();
    650 	outb(com+com_cfcr, CFCR_DLAB);
    651 	rate = ttspeedtab(comdefaultrate, comspeedtab);
    652 	outb(com+com_data, rate & 0xFF);
    653 	outb(com+com_ier, rate >> 8);
    654 	outb(com+com_cfcr, CFCR_8BITS);
    655 	outb(com+com_ier, IER_ERXRDY | IER_ETXRDY);
    656 	outb(com+com_fifo, FIFO_ENABLE|FIFO_RCV_RST|FIFO_XMT_RST|FIFO_TRIGGER_14);
    657 	stat = inb(com+com_iir);
    658 	splx(s);
    659 }
    660 
    661 comcngetc(dev)
    662 {
    663 	register com = com_addr[UNIT(dev)];
    664 	short stat;
    665 	int c, s;
    666 
    667 #ifdef lint
    668 	stat = dev; if (stat) return(0);
    669 #endif
    670 	s = splhigh();
    671 	while (((stat = inb(com+com_lsr)) & LSR_RXRDY) == 0)
    672 		;
    673 	c = inb(com+com_data);
    674 	stat = inb(com+com_iir);
    675 	splx(s);
    676 	return(c);
    677 }
    678 
    679 /*
    680  * Console kernel output character routine.
    681  */
    682 comcnputc(dev, c)
    683 	dev_t dev;
    684 	register int c;
    685 {
    686 	register com = com_addr[UNIT(dev)];
    687 	register int timo;
    688 	short stat;
    689 	int s = splhigh();
    690 
    691 #ifdef lint
    692 	stat = dev; if (stat) return;
    693 #endif
    694 #ifdef KGDB
    695 	if (dev != kgdb_dev)
    696 #endif
    697 	if (comconsinit == 0) {
    698 		(void) cominit(UNIT(dev), comdefaultrate);
    699 		comconsinit = 1;
    700 	}
    701 	/* wait for any pending transmission to finish */
    702 	timo = 50000;
    703 	while (((stat = inb(com+com_lsr)) & LSR_TXRDY) == 0 && --timo)
    704 		;
    705 	outb(com+com_data, c);
    706 	/* wait for this transmission to complete */
    707 	timo = 1500000;
    708 	while (((stat = inb(com+com_lsr)) & LSR_TXRDY) == 0 && --timo)
    709 		;
    710 	/* clear any interrupts generated by this transmission */
    711 	stat = inb(com+com_iir);
    712 	splx(s);
    713 }
    714 #endif
    715