com.c

早期freebsd实现

	c = inb(com+com_data);
	if ((tp->t_state & TS_ISOPEN) == 0) {
#ifdef KGDB
		/* we don't care about parity errors */
		if (((stat & (LSR_BI|LSR_FE|LSR_PE)) == LSR_PE) &&
		    kgdb_dev == makedev(commajor, unit) && c == FRAME_END)
			kgdb_connect(0); /* trap into kgdb */
#endif
		return;
	}
	if (stat & (LSR_BI | LSR_FE))
		c |= TTY_FE;
	else if (stat & LSR_PE)
		c |= TTY_PE;
	else if (stat & LSR_OE)
		log(LOG_WARNING, "com%d: silo overflow\n", unit);
	(*linesw[tp->t_line].l_rint)(c, tp);
}

commint(unit, com)
	register int unit;
	register com;
{
	register struct tty *tp;
	register int stat;

	tp = &com_tty[unit];
	stat = inb(com+com_msr);
	if ((stat & MSR_DDCD) && (comsoftCAR & (1 << unit)) == 0) {
		if (stat & MSR_DCD)
			(void)(*linesw[tp->t_line].l_modem)(tp, 1);
		else if ((*linesw[tp->t_line].l_modem)(tp, 0) == 0)
			outb(com+com_mcr,
				inb(com+com_mcr) & ~(MCR_DTR | MCR_RTS) | MCR_IENABLE);
	} else if ((stat & MSR_DCTS) && (tp->t_state & TS_ISOPEN) &&
		   (tp->t_flags & CRTSCTS)) {
		/* the line is up and we want to do rts/cts flow control */
		if (stat & MSR_CTS) {
			tp->t_state &=~ TS_TTSTOP;
			ttstart(tp);
		} else
			tp->t_state |= TS_TTSTOP;
	}
}

comioctl(dev, cmd, data, flag, p)
	dev_t dev;
	int cmd, flag;
	caddr_t data;
	struct proc *p;
{
	register struct tty *tp;
	register int unit = UNIT(dev);
	register com;
	register int error;
 
	tp = &com_tty[unit];
	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
	if (error >= 0)
		return (error);
	error = ttioctl(tp, cmd, data, flag);
	if (error >= 0)
		return (error);

	com = com_addr[unit];
	switch (cmd) {

	case TIOCSBRK:
		outb(com+com_cfcr, inb(com+com_cfcr) | CFCR_SBREAK);
		break;

	case TIOCCBRK:
		outb(com+com_cfcr, inb(com+com_cfcr) & ~CFCR_SBREAK);
		break;

	case TIOCSDTR:
		(void) commctl(dev, MCR_DTR | MCR_RTS, DMBIS);
		break;

	case TIOCCDTR:
		(void) commctl(dev, MCR_DTR | MCR_RTS, DMBIC);
		break;

	case TIOCMSET:
		(void) commctl(dev, *(int *)data, DMSET);
		break;

	case TIOCMBIS:
		(void) commctl(dev, *(int *)data, DMBIS);
		break;

	case TIOCMBIC:
		(void) commctl(dev, *(int *)data, DMBIC);
		break;

	case TIOCMGET:
		*(int *)data = commctl(dev, 0, DMGET);
		break;

	default:
		return (ENOTTY);
	}
	return (0);
}

comparam(tp, t)
	register struct tty *tp;
	register struct termios *t;
{
	register com;
	register int cfcr, cflag = t->c_cflag;
	int unit = UNIT(tp->t_dev);
	int ospeed = ttspeedtab(t->c_ospeed, comspeedtab);
 
	/* check requested parameters */
        if (ospeed < 0 || (t->c_ispeed && t->c_ispeed != t->c_ospeed))
                return(EINVAL);
        /* and copy to tty */
        tp->t_ispeed = t->c_ispeed;
        tp->t_ospeed = t->c_ospeed;
        tp->t_cflag = cflag;

	com = com_addr[unit];
	outb(com+com_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS /*| IER_EMSC*/);
	if (ospeed == 0) {
		(void) commctl(unit, 0, DMSET);	/* hang up line */
		return(0);
	}
	outb(com+com_cfcr, inb(com+com_cfcr) | CFCR_DLAB);
	outb(com+com_data, ospeed & 0xFF);
	outb(com+com_ier, ospeed >> 8);
	switch (cflag&CSIZE) {
	case CS5:
		cfcr = CFCR_5BITS; break;
	case CS6:
		cfcr = CFCR_6BITS; break;
	case CS7:
		cfcr = CFCR_7BITS; break;
	case CS8:
		cfcr = CFCR_8BITS; break;
	}
	if (cflag&PARENB) {
		cfcr |= CFCR_PENAB;
		if ((cflag&PARODD) == 0)
			cfcr |= CFCR_PEVEN;
	}
	if (cflag&CSTOPB)
		cfcr |= CFCR_STOPB;
	outb(com+com_cfcr, cfcr);

	if (com_hasfifo & (1 << unit))
		outb(com+com_fifo, FIFO_ENABLE | FIFO_TRIGGER_14);

	return(0);
}
 
void
comstart(tp)
	register struct tty *tp;
{
	register com;
	int s, unit, c;
 
	unit = UNIT(tp->t_dev);
	com = com_addr[unit];
	s = spltty();
	if (tp->t_state & (TS_TIMEOUT|TS_TTSTOP))
		goto out;
	if (tp->t_outq.c_cc <= tp->t_lowat) {
		if (tp->t_state&TS_ASLEEP) {
			tp->t_state &= ~TS_ASLEEP;
			wakeup((caddr_t)&tp->t_outq);
		}
		selwakeup(&tp->t_wsel);
	}
	if (tp->t_outq.c_cc == 0)
		goto out;
	if (inb(com+com_lsr) & LSR_TXRDY) {
		c = getc(&tp->t_outq);
		tp->t_state |= TS_BUSY;
		outb(com+com_data, c);
		if (com_hasfifo & (1 << unit))
			for (c = 1; c < 16 && tp->t_outq.c_cc; ++c)
				outb(com+com_data, getc(&tp->t_outq));
	}
out:
	splx(s);
}
 
/*
 * Stop output on a line.
 */
/*ARGSUSED*/
comstop(tp, flag)
	register struct tty *tp;
{
	register int s;

	s = spltty();
	if (tp->t_state & TS_BUSY) {
		if ((tp->t_state&TS_TTSTOP)==0)
			tp->t_state |= TS_FLUSH;
	}
	splx(s);
}
 
commctl(dev, bits, how)
	dev_t dev;
	int bits, how;
{
	register com;
	register int unit;
	int s;

	unit = UNIT(dev);
	com = com_addr[unit];
	s = spltty();
	switch (how) {

	case DMSET:
		outb(com+com_mcr, bits | MCR_IENABLE);
		break;

	case DMBIS:
		outb(com+com_mcr, inb(com+com_mcr) | bits | MCR_IENABLE);
		break;

	case DMBIC:
		outb(com+com_mcr, inb(com+com_mcr) & ~bits | MCR_IENABLE);
		break;

	case DMGET:
		bits = inb(com+com_msr);
		break;
	}
	(void) splx(s);
	return(bits);
}

/*
 * Following are all routines needed for COM to act as console
 */
#include <i386/i386/cons.h>

comcnprobe(cp)
	struct consdev *cp;
{
	int unit;

	/* locate the major number */
	for (commajor = 0; commajor < nchrdev; commajor++)
		if (cdevsw[commajor].d_open == comopen)
			break;

	/* XXX: ick */
	unit = CONUNIT;
	com_addr[CONUNIT] = CONADDR;

	/* make sure hardware exists?  XXX */

	/* initialize required fields */
	cp->cn_dev = makedev(commajor, unit);
	cp->cn_tp = &com_tty[unit];
#ifdef	COMCONSOLE
	cp->cn_pri = CN_REMOTE;		/* Force a serial port console */
#else
	cp->cn_pri = CN_NORMAL;
#endif
}

comcninit(cp)
	struct consdev *cp;
{
	int unit = UNIT(cp->cn_dev);

	cominit(unit, comdefaultrate);
	comconsole = unit;
	comconsinit = 1;
}

cominit(unit, rate)
	int unit, rate;
{
	register int com;
	int s;
	short stat;

#ifdef lint
	stat = unit; if (stat) return;
#endif
	com = com_addr[unit];
	s = splhigh();
	outb(com+com_cfcr, CFCR_DLAB);
	rate = ttspeedtab(comdefaultrate, comspeedtab);
	outb(com+com_data, rate & 0xFF);
	outb(com+com_ier, rate >> 8);
	outb(com+com_cfcr, CFCR_8BITS);
	outb(com+com_ier, IER_ERXRDY | IER_ETXRDY);
	outb(com+com_fifo, FIFO_ENABLE|FIFO_RCV_RST|FIFO_XMT_RST|FIFO_TRIGGER_14);
	stat = inb(com+com_iir);
	splx(s);
}

comcngetc(dev)
{
	register com = com_addr[UNIT(dev)];
	short stat;
	int c, s;

#ifdef lint
	stat = dev; if (stat) return(0);
#endif
	s = splhigh();
	while (((stat = inb(com+com_lsr)) & LSR_RXRDY) == 0)
		;
	c = inb(com+com_data);
	stat = inb(com+com_iir);
	splx(s);
	return(c);
}

/*
 * Console kernel output character routine.
 */
comcnputc(dev, c)
	dev_t dev;
	register int c;
{
	register com = com_addr[UNIT(dev)];
	register int timo;
	short stat;
	int s = splhigh();

#ifdef lint
	stat = dev; if (stat) return;
#endif
#ifdef KGDB
	if (dev != kgdb_dev)
#endif
	if (comconsinit == 0) {
		(void) cominit(UNIT(dev), comdefaultrate);
		comconsinit = 1;
	}
	/* wait for any pending transmission to finish */
	timo = 50000;
	while (((stat = inb(com+com_lsr)) & LSR_TXRDY) == 0 && --timo)
		;
	outb(com+com_data, c);
	/* wait for this transmission to complete */
	timo = 1500000;
	while (((stat = inb(com+com_lsr)) & LSR_TXRDY) == 0 && --timo)
		;
	/* clear any interrupts generated by this transmission */
	stat = inb(com+com_iir);
	splx(s);
}
#endif