Home | History | Annotate | Line # | Download | only in ic
com.c revision 1.12 
      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  *	from: @(#)com.c	7.5 (Berkeley) 5/16/91
     34  *	$Id: com.c,v 1.12 1993/08/29 13:47:03 deraadt Exp $
     35  */
     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 "select.h"
     47 #include "tty.h"
     48 #include "proc.h"
     49 #include "user.h"
     50 #include "conf.h"
     51 #include "file.h"
     52 #include "uio.h"
     53 #include "kernel.h"
     54 #include "syslog.h"
     55 #include "types.h"
     56 
     57 #include "i386/isa/isa_device.h"
     58 #include "i386/isa/comreg.h"
     59 #include "i386/isa/ic/ns16550.h"
     60 #define cominor(d)
     61 
     62 int 	comprobe(), comattach(), comintr(), comparam();
     63 void	comstart();
     64 
     65 struct	isa_driver comdriver = {
     66 	comprobe, comattach, "com"
     67 };
     68 
     69 int	comsoftCAR;
     70 int	com_active;
     71 int	com_hasfifo;
     72 int	ncom = NCOM;
     73 #ifdef COMCONSOLE
     74 int	comconsole = COMCONSOLE;
     75 #else
     76 int	comconsole = -1;
     77 #endif
     78 int	comconsinit;
     79 int	comdefaultrate = TTYDEF_SPEED;
     80 int	commajor;
     81 short com_addr[NCOM];
     82 struct	tty *com_tty[NCOM];
     83 
     84 struct speedtab comspeedtab[] = {
     85 	0,	0,
     86 	50,	COMBRD(50),
     87 	75,	COMBRD(75),
     88 	110,	COMBRD(110),
     89 	134,	COMBRD(134),
     90 	150,	COMBRD(150),
     91 	200,	COMBRD(200),
     92 	300,	COMBRD(300),
     93 	600,	COMBRD(600),
     94 	1200,	COMBRD(1200),
     95 	1800,	COMBRD(1800),
     96 	2400,	COMBRD(2400),
     97 	4800,	COMBRD(4800),
     98 	9600,	COMBRD(9600),
     99 	19200,	COMBRD(19200),
    100 	38400,	COMBRD(38400),
    101 	57600,	COMBRD(57600),
    102 	-1,	-1
    103 };
    104 
    105 extern	struct tty *constty;
    106 #ifdef KGDB
    107 #include "machine/remote-sl.h"
    108 
    109 extern int kgdb_dev;
    110 extern int kgdb_rate;
    111 extern int kgdb_debug_init;
    112 #endif
    113 
    114 #define	UNIT(x)		(minor(x))
    115 
    116 comprobe(dev)
    117 struct isa_device *dev;
    118 {
    119 	/* force access to id reg */
    120 	outb(dev->id_iobase+com_cfcr, 0);
    121 	outb(dev->id_iobase+com_iir, 0);
    122 	DELAY(100);
    123 	if ((inb(dev->id_iobase+com_iir) & 0x38) == 0)
    124 		return(8);
    125 	return(0);
    126 }
    127 
    128 
    129 int
    130 comattach(isdp)
    131 struct isa_device *isdp;
    132 {
    133 	struct	tty	*tp;
    134 	u_char		unit;
    135 	int		port = isdp->id_iobase;
    136 
    137 	unit = isdp->id_unit;
    138 	if (unit == comconsole)
    139 		DELAY(1000);
    140 	com_addr[unit] = port;
    141 	com_active |= 1 << unit;
    142 	comsoftCAR |= 1 << unit;	/* XXX */
    143 
    144 	/* look for a NS 16550AF UART with FIFOs */
    145 	outb(port+com_fifo, FIFO_ENABLE|FIFO_RCV_RST|FIFO_XMT_RST|FIFO_TRIGGER_4);
    146 	DELAY(100);
    147 	if ((inb(port+com_iir) & IIR_FIFO_MASK) == IIR_FIFO_MASK) {
    148 		com_hasfifo |= 1 << unit;
    149 		printf("com%d: fifo\n", isdp->id_unit);
    150 	}
    151 
    152 	outb(port+com_ier, 0);
    153 	outb(port+com_mcr, 0 | MCR_IENABLE);
    154 #ifdef KGDB
    155 	if (kgdb_dev == makedev(commajor, unit)) {
    156 		if (comconsole == unit)
    157 			kgdb_dev = -1;	/* can't debug over console port */
    158 		else {
    159 			(void) cominit(unit, kgdb_rate);
    160 			if (kgdb_debug_init) {
    161 				/*
    162 				 * Print prefix of device name,
    163 				 * let kgdb_connect print the rest.
    164 				 */
    165 				printf("com%d: ", unit);
    166 				kgdb_connect(1);
    167 			} else
    168 				printf("com%d: kgdb enabled\n", unit);
    169 		}
    170 	}
    171 #endif
    172 	/*
    173 	 * Need to reset baud rate, etc. of next print so reset comconsinit.
    174 	 * Also make sure console is always "hardwired"
    175 	 */
    176 	if (unit == comconsole) {
    177 		comconsinit = 0;
    178 		comsoftCAR |= (1 << unit);
    179 	}
    180 	return (1);
    181 }
    182 
    183 /* ARGSUSED */
    184 comopen(dev_t dev, int flag, int mode, struct proc *p)
    185 {
    186 	register struct tty *tp;
    187 	register int unit;
    188 	int error = 0;
    189 
    190 	unit = UNIT(dev);
    191 	if (unit >= NCOM || (com_active & (1 << unit)) == 0)
    192 		return (ENXIO);
    193 	if(!com_tty[unit]) {
    194 		tp = com_tty[unit] = ttymalloc();
    195 	} else
    196 		tp = com_tty[unit];
    197 	tp->t_oproc = comstart;
    198 	tp->t_param = comparam;
    199 	tp->t_dev = dev;
    200 	if ((tp->t_state & TS_ISOPEN) == 0) {
    201 		tp->t_state |= TS_WOPEN;
    202 		ttychars(tp);
    203 		if (tp->t_ispeed == 0) {
    204 			tp->t_iflag = TTYDEF_IFLAG;
    205 			tp->t_oflag = TTYDEF_OFLAG;
    206 			tp->t_cflag = TTYDEF_CFLAG;
    207 			tp->t_lflag = TTYDEF_LFLAG;
    208 			tp->t_ispeed = tp->t_ospeed = comdefaultrate;
    209 		}
    210 		comparam(tp, &tp->t_termios);
    211 		ttsetwater(tp);
    212 	} else if (tp->t_state&TS_XCLUDE && p->p_ucred->cr_uid != 0)
    213 		return (EBUSY);
    214 	(void) spltty();
    215 	(void) commctl(dev, MCR_DTR | MCR_RTS, DMSET);
    216 	if ((comsoftCAR & (1 << unit)) || (commctl(dev, 0, DMGET) & MSR_DCD))
    217 		tp->t_state |= TS_CARR_ON;
    218 	while ((flag&O_NONBLOCK) == 0 && (tp->t_cflag&CLOCAL) == 0 &&
    219 	       (tp->t_state & TS_CARR_ON) == 0) {
    220 		tp->t_state |= TS_WOPEN;
    221 		if (error = ttysleep(tp, (caddr_t)&tp->t_rawq, TTIPRI | PCATCH,
    222 		    ttopen, 0))
    223 			break;
    224 	}
    225 	(void) spl0();
    226 	if (error == 0)
    227 		error = (*linesw[tp->t_line].l_open)(dev, tp);
    228 	return (error);
    229 }
    230 
    231 /*ARGSUSED*/
    232 comclose(dev, flag, mode, p)
    233 	dev_t dev;
    234 	int flag, mode;
    235 	struct proc *p;
    236 {
    237 	register struct tty *tp;
    238 	register com;
    239 	register int unit;
    240 
    241 	unit = UNIT(dev);
    242 	com = com_addr[unit];
    243 	tp = com_tty[unit];
    244 	(*linesw[tp->t_line].l_close)(tp, flag);
    245 	outb(com+com_cfcr, inb(com+com_cfcr) & ~CFCR_SBREAK);
    246 #ifdef KGDB
    247 	/* do not disable interrupts if debugging */
    248 	if (kgdb_dev != makedev(commajor, unit))
    249 #endif
    250 	outb(com+com_ier, 0);
    251 	if (tp->t_cflag&HUPCL || tp->t_state&TS_WOPEN ||
    252 	    (tp->t_state&TS_ISOPEN) == 0)
    253 		(void) commctl(dev, 0, DMSET);
    254 	ttyclose(tp);
    255 	ttyfree(tp);
    256 	com_tty[unit] = (struct tty *)NULL;
    257 	return(0);
    258 }
    259 
    260 comread(dev, uio, flag)
    261 	dev_t dev;
    262 	struct uio *uio;
    263 {
    264 	register struct tty *tp = com_tty[UNIT(dev)];
    265 
    266 	return ((*linesw[tp->t_line].l_read)(tp, uio, flag));
    267 }
    268 
    269 comwrite(dev, uio, flag)
    270 	dev_t dev;
    271 	struct uio *uio;
    272 {
    273 	int unit = UNIT(dev);
    274 	register struct tty *tp = com_tty[unit];
    275 
    276 	/*
    277 	 * (XXX) We disallow virtual consoles if the physical console is
    278 	 * a serial port.  This is in case there is a display attached that
    279 	 * is not the console.  In that situation we don't need/want the X
    280 	 * server taking over the console.
    281 	 */
    282 	if (constty && unit == comconsole)
    283 		constty = NULL;
    284 	return ((*linesw[tp->t_line].l_write)(tp, uio, flag));
    285 }
    286 
    287 comintr(unit)
    288 	register int unit;
    289 {
    290 	register com;
    291 	register u_char code;
    292 	register struct tty *tp;
    293 
    294 	unit;
    295 	com = com_addr[unit];
    296 	while (1) {
    297 		code = inb(com+com_iir);
    298 		switch (code & IIR_IMASK) {
    299 		case IIR_NOPEND:
    300 			return (1);
    301 		case IIR_RXTOUT:
    302 		case IIR_RXRDY:
    303 			tp = com_tty[unit];
    304 /*
    305  * Process received bytes.  Inline for speed...
    306  */
    307 #ifdef KGDB
    308 #define	RCVBYTE() \
    309 			code = inb(com+com_data); \
    310 			if ((tp->t_state & TS_ISOPEN) == 0) { \
    311 				if (kgdb_dev == makedev(commajor, unit) && \
    312 				    code == FRAME_END) \
    313 					kgdb_connect(0); /* trap into kgdb */ \
    314 			} else \
    315 				(*linesw[tp->t_line].l_rint)(code, tp)
    316 #else
    317 #define	RCVBYTE() \
    318 			code = inb(com+com_data); \
    319 			if (tp->t_state & TS_ISOPEN) \
    320 				(*linesw[tp->t_line].l_rint)(code, tp)
    321 #endif
    322 
    323 			RCVBYTE();
    324 
    325 			if (com_hasfifo & (1 << unit))
    326 				while ((code = inb(com+com_lsr)) & LSR_RCV_MASK) {
    327 					if (code == LSR_RXRDY) {
    328 						RCVBYTE();
    329 					} else
    330 						comeint(unit, code, com);
    331 				}
    332 			break;
    333 		case IIR_TXRDY:
    334 			tp = com_tty[unit];
    335 			tp->t_state &=~ (TS_BUSY|TS_FLUSH);
    336 			if (tp->t_line)
    337 				(*linesw[tp->t_line].l_start)(tp);
    338 			else
    339 				comstart(tp);
    340 			break;
    341 		case IIR_RLS:
    342 			comeint(unit, inb(com+com_lsr), com);
    343 			break;
    344 		default:
    345 			if (code & IIR_NOPEND)
    346 				return (1);
    347 			log(LOG_WARNING, "com%d: weird interrupt: 0x%x\n",
    348 			    unit, code);
    349 			/* fall through */
    350 		case IIR_MLSC:
    351 			commint(unit, com);
    352 			break;
    353 		}
    354 	}
    355 }
    356 
    357 comeint(unit, stat, com)
    358 	register int unit, stat;
    359 	register com;
    360 {
    361 	register struct tty *tp;
    362 	register int c;
    363 
    364 	tp = com_tty[unit];
    365 	c = inb(com+com_data);
    366 	if ((tp->t_state & TS_ISOPEN) == 0) {
    367 #ifdef KGDB
    368 		/* we don't care about parity errors */
    369 		if (((stat & (LSR_BI|LSR_FE|LSR_PE)) == LSR_PE) &&
    370 		    kgdb_dev == makedev(commajor, unit) && c == FRAME_END)
    371 			kgdb_connect(0); /* trap into kgdb */
    372 #endif
    373 		return;
    374 	}
    375 	if (stat & (LSR_BI | LSR_FE))
    376 		c |= TTY_FE;
    377 	else if (stat & LSR_PE)
    378 		c |= TTY_PE;
    379 	else if (stat & LSR_OE) {			/* 30 Aug 92*/
    380 		c |= TTY_PE;	/* Ought to have it's own define... */
    381 		log(LOG_WARNING, "com%d: silo overflow\n", unit);
    382 	}
    383 	(*linesw[tp->t_line].l_rint)(c, tp);
    384 }
    385 
    386 commint(unit, com)
    387 	register int unit;
    388 	register com;
    389 {
    390 	register struct tty *tp;
    391 	register int stat;
    392 
    393 	tp = com_tty[unit];
    394 	stat = inb(com+com_msr);
    395 	if ((stat & MSR_DDCD) && (comsoftCAR & (1 << unit)) == 0) {
    396 		if (stat & MSR_DCD)
    397 			(void)(*linesw[tp->t_line].l_modem)(tp, 1);
    398 		else if ((*linesw[tp->t_line].l_modem)(tp, 0) == 0)
    399 			outb(com+com_mcr,
    400 				inb(com+com_mcr) & ~(MCR_DTR | MCR_RTS) | MCR_IENABLE);
    401 	} else if ((stat & MSR_DCTS) && (tp->t_state & TS_ISOPEN) &&
    402 		   (tp->t_flags & CRTSCTS)) {
    403 		/* the line is up and we want to do rts/cts flow control */
    404 		if (stat & MSR_CTS) {
    405 			tp->t_state &=~ TS_TTSTOP;
    406 			ttstart(tp);
    407 		} else
    408 			tp->t_state |= TS_TTSTOP;
    409 	}
    410 }
    411 
    412 comioctl(dev, cmd, data, flag)
    413 	dev_t dev;
    414 	caddr_t data;
    415 {
    416 	register struct tty *tp;
    417 	register int unit = UNIT(dev);
    418 	register com;
    419 	register int error;
    420 
    421 	tp = com_tty[unit];
    422 	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag);
    423 	if (error >= 0)
    424 		return (error);
    425 	error = ttioctl(tp, cmd, data, flag);
    426 	if (error >= 0)
    427 		return (error);
    428 
    429 	com = com_addr[unit];
    430 	switch (cmd) {
    431 
    432 	case TIOCSBRK:
    433 		outb(com+com_cfcr, inb(com+com_cfcr) | CFCR_SBREAK);
    434 		break;
    435 
    436 	case TIOCCBRK:
    437 		outb(com+com_cfcr, inb(com+com_cfcr) & ~CFCR_SBREAK);
    438 		break;
    439 
    440 	case TIOCSDTR:
    441 		(void) commctl(dev, MCR_DTR | MCR_RTS, DMBIS);
    442 		break;
    443 
    444 	case TIOCCDTR:
    445 		(void) commctl(dev, MCR_DTR | MCR_RTS, DMBIC);
    446 		break;
    447 
    448 	case TIOCMSET:
    449 		(void) commctl(dev, *(int *)data, DMSET);
    450 		break;
    451 
    452 	case TIOCMBIS:
    453 		(void) commctl(dev, *(int *)data, DMBIS);
    454 		break;
    455 
    456 	case TIOCMBIC:
    457 		(void) commctl(dev, *(int *)data, DMBIC);
    458 		break;
    459 
    460 	case TIOCMGET:
    461 		*(int *)data = commctl(dev, 0, DMGET);
    462 		break;
    463 
    464 	default:
    465 		return (ENOTTY);
    466 	}
    467 	return (0);
    468 }
    469 
    470 comparam(tp, t)
    471 	register struct tty *tp;
    472 	register struct termios *t;
    473 {
    474 	register com;
    475 	register int cfcr, cflag = t->c_cflag;
    476 	int unit = UNIT(tp->t_dev);
    477 	int ospeed = ttspeedtab(t->c_ospeed, comspeedtab);
    478 
    479 	/* check requested parameters */
    480         if (ospeed < 0 || (t->c_ispeed && t->c_ispeed != t->c_ospeed))
    481                 return(EINVAL);
    482         /* and copy to tty */
    483         tp->t_ispeed = t->c_ispeed;
    484         tp->t_ospeed = t->c_ospeed;
    485         tp->t_cflag = cflag;
    486 
    487 	com = com_addr[unit];
    488 	outb(com+com_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS /*| IER_EMSC*/);
    489 	if (ospeed == 0) {
    490 		(void) commctl(unit, 0, DMSET);	/* hang up line */
    491 		return(0);
    492 	}
    493 	outb(com+com_cfcr, inb(com+com_cfcr) | CFCR_DLAB);
    494 	outb(com+com_data, ospeed & 0xFF);
    495 	outb(com+com_ier, ospeed >> 8);
    496 	switch (cflag&CSIZE) {
    497 	case CS5:
    498 		cfcr = CFCR_5BITS; break;
    499 	case CS6:
    500 		cfcr = CFCR_6BITS; break;
    501 	case CS7:
    502 		cfcr = CFCR_7BITS; break;
    503 	case CS8:
    504 		cfcr = CFCR_8BITS; break;
    505 	}
    506 	if (cflag&PARENB) {
    507 		cfcr |= CFCR_PENAB;
    508 		if ((cflag&PARODD) == 0)
    509 			cfcr |= CFCR_PEVEN;
    510 	}
    511 	if (cflag&CSTOPB)
    512 		cfcr |= CFCR_STOPB;
    513 	outb(com+com_cfcr, cfcr);
    514 
    515 	if (com_hasfifo & (1 << unit))
    516 		outb(com+com_fifo, FIFO_ENABLE | FIFO_TRIGGER_4);
    517 
    518 	return(0);
    519 }
    520 
    521 void
    522 comstart(tp)
    523 	register struct tty *tp;
    524 {
    525 	register com;
    526 	int s, unit, c;
    527 
    528 	unit = UNIT(tp->t_dev);
    529 	com = com_addr[unit];
    530 	s = spltty();
    531 	if (tp->t_state & (TS_TIMEOUT|TS_TTSTOP))
    532 		goto out;
    533 	if (tp->t_outq.c_cc <= tp->t_lowat) {
    534 		if (tp->t_state&TS_ASLEEP) {
    535 			tp->t_state &= ~TS_ASLEEP;
    536 			wakeup((caddr_t)&tp->t_outq);
    537 		}
    538 		selwakeup(&tp->t_wsel);
    539 	}
    540 	if (tp->t_outq.c_cc == 0)
    541 		goto out;
    542 	if (inb(com+com_lsr) & LSR_TXRDY) {
    543 		c = getc(&tp->t_outq);
    544 		tp->t_state |= TS_BUSY;
    545 		outb(com+com_data, c);
    546 		if (com_hasfifo & (1 << unit))
    547 			for (c = 1; c < 16 && tp->t_outq.c_cc; ++c)
    548 				outb(com+com_data, getc(&tp->t_outq));
    549 	}
    550 out:
    551 	splx(s);
    552 }
    553 
    554 /*
    555  * Stop output on a line.
    556  */
    557 /*ARGSUSED*/
    558 comstop(tp, flag)
    559 	register struct tty *tp;
    560 {
    561 	register int s;
    562 
    563 	s = spltty();
    564 	if (tp->t_state & TS_BUSY) {
    565 		if ((tp->t_state&TS_TTSTOP)==0)
    566 			tp->t_state |= TS_FLUSH;
    567 	}
    568 	splx(s);
    569 }
    570 
    571 commctl(dev, bits, how)
    572 	dev_t dev;
    573 	int bits, how;
    574 {
    575 	register com;
    576 	register int unit;
    577 	int s;
    578 
    579 	unit = UNIT(dev);
    580 	com = com_addr[unit];
    581 	s = spltty();
    582 	switch (how) {
    583 
    584 	case DMSET:
    585 		outb(com+com_mcr, bits | MCR_IENABLE);
    586 		break;
    587 
    588 	case DMBIS:
    589 		outb(com+com_mcr, inb(com+com_mcr) | bits | MCR_IENABLE);
    590 		break;
    591 
    592 	case DMBIC:
    593 		outb(com+com_mcr, inb(com+com_mcr) & ~bits | MCR_IENABLE);
    594 		break;
    595 
    596 	case DMGET:
    597 		bits = inb(com+com_msr);
    598 		break;
    599 	}
    600 	(void) splx(s);
    601 	return(bits);
    602 }
    603 
    604 /*
    605  * Following are all routines needed for COM to act as console
    606  */
    607 #include "i386/i386/cons.h"
    608 
    609 comcnprobe(cp)
    610 	struct consdev *cp;
    611 {
    612 	int unit;
    613 
    614 	/* locate the major number */
    615 	for (commajor = 0; commajor < nchrdev; commajor++)
    616 		if (cdevsw[commajor].d_open == comopen)
    617 			break;
    618 
    619 	/* XXX: ick */
    620 	unit = CONUNIT;
    621 	com_addr[CONUNIT] = CONADDR;
    622 
    623 	/* make sure hardware exists?  XXX */
    624 
    625 	/* initialize required fields */
    626 	cp->cn_dev = makedev(commajor, unit);
    627 #ifdef	COMCONSOLE
    628 	cp->cn_pri = CN_REMOTE;		/* Force a serial port console */
    629 #else
    630 	cp->cn_pri = CN_NORMAL;
    631 #endif
    632 }
    633 
    634 comcninit(cp)
    635 	struct consdev *cp;
    636 {
    637 	int unit = UNIT(cp->cn_dev);
    638 
    639 	cominit(unit, comdefaultrate);
    640 	comconsole = unit;
    641 	comconsinit = 1;
    642 }
    643 
    644 cominit(unit, rate)
    645 	int unit, rate;
    646 {
    647 	register int com;
    648 	int s;
    649 	short stat;
    650 
    651 #ifdef lint
    652 	stat = unit; if (stat) return;
    653 #endif
    654 	com = com_addr[unit];
    655 	s = splhigh();
    656 	outb(com+com_cfcr, CFCR_DLAB);
    657 	rate = ttspeedtab(comdefaultrate, comspeedtab);
    658 	outb(com+com_data, rate & 0xFF);
    659 	outb(com+com_ier, rate >> 8);
    660 	outb(com+com_cfcr, CFCR_8BITS);
    661 	outb(com+com_ier, IER_ERXRDY | IER_ETXRDY);
    662 	outb(com+com_fifo, FIFO_ENABLE|FIFO_RCV_RST|FIFO_XMT_RST|FIFO_TRIGGER_4);
    663 	stat = inb(com+com_iir);
    664 	splx(s);
    665 }
    666 
    667 comcngetc(dev)
    668 {
    669 	register com = com_addr[UNIT(dev)];
    670 	short stat;
    671 	int c, s;
    672 
    673 #ifdef lint
    674 	stat = dev; if (stat) return(0);
    675 #endif
    676 	s = splhigh();
    677 	while (((stat = inb(com+com_lsr)) & LSR_RXRDY) == 0)
    678 		;
    679 	c = inb(com+com_data);
    680 	stat = inb(com+com_iir);
    681 	splx(s);
    682 	return(c);
    683 }
    684 
    685 /*
    686  * Console kernel output character routine.
    687  */
    688 comcnputc(dev, c)
    689 	dev_t dev;
    690 	register int c;
    691 {
    692 	register com = com_addr[UNIT(dev)];
    693 	register int timo;
    694 	short stat;
    695 	int s = splhigh();
    696 
    697 #ifdef lint
    698 	stat = dev; if (stat) return;
    699 #endif
    700 #ifdef KGDB
    701 	if (dev != kgdb_dev)
    702 #endif
    703 	if (comconsinit == 0) {
    704 		(void) cominit(UNIT(dev), comdefaultrate);
    705 		comconsinit = 1;
    706 	}
    707 	/* wait for any pending transmission to finish */
    708 	timo = 50000;
    709 	while (((stat = inb(com+com_lsr)) & LSR_TXRDY) == 0 && --timo)
    710 		;
    711 	outb(com+com_data, c);
    712 	/* wait for this transmission to complete */
    713 	timo = 1500000;
    714 	while (((stat = inb(com+com_lsr)) & LSR_TXRDY) == 0 && --timo)
    715 		;
    716 	/* clear any interrupts generated by this transmission */
    717 	stat = inb(com+com_iir);
    718 	splx(s);
    719 }
    720 
    721 int
    722 comselect(dev, rw, p)
    723 	dev_t dev;
    724 	int rw;
    725 	struct proc *p;
    726 {
    727 	register struct tty *tp = com_tty[UNIT(dev)];
    728 	int nread;
    729 	int s = spltty();
    730         struct proc *selp;
    731 
    732 	switch (rw) {
    733 
    734 	case FREAD:
    735 		nread = ttnread(tp);
    736 		if (nread > 0 ||
    737 		   ((tp->t_cflag&CLOCAL) == 0 && (tp->t_state&TS_CARR_ON) == 0))
    738 			goto win;
    739 		selrecord(p, &tp->t_rsel);
    740 		break;
    741 
    742 	case FWRITE:
    743 		if (tp->t_outq.c_cc <= tp->t_lowat)
    744 			goto win;
    745 		selrecord(p, &tp->t_wsel);
    746 		break;
    747 	}
    748 	splx(s);
    749 	return (0);
    750   win:
    751 	splx(s);
    752 	return (1);
    753 }
    754 
    755 #endif
    756