com.c

MIPS处理器的bootloader,龙芯就是用的修改过的PMON2

		if (ISSET(sc->sc_mcr, MCR_DTR)) {
			if (!ISSET(sc->sc_mcr, MCR_RTS)) {
				SET(sc->sc_mcr, MCR_RTS);
				bus_space_write_1(iot, ioh, com_mcr, sc->sc_mcr);
			}
		} else {
			if (ISSET(sc->sc_mcr, MCR_RTS)) {
				CLR(sc->sc_mcr, MCR_RTS);
				bus_space_write_1(iot, ioh, com_mcr, sc->sc_mcr);
			}
		}
		sc->sc_dtr = MCR_DTR | MCR_RTS;
	} else
		sc->sc_dtr = MCR_DTR;

	/* and copy to tty */
	tp->t_ispeed = t->c_ispeed;
	tp->t_ospeed = t->c_ospeed;
	oldcflag = tp->t_cflag;
	tp->t_cflag = t->c_cflag;

	/*
	 * If DCD is off and MDMBUF is changed, ask the tty layer if we should
	 * stop the device.
	 */
	if (!ISSET(sc->sc_msr, MSR_DCD) &&
	    !ISSET(sc->sc_swflags, COM_SW_SOFTCAR) &&
	    ISSET(oldcflag, MDMBUF) != ISSET(tp->t_cflag, MDMBUF) &&
	    (*linesw[tp->t_line].l_modem)(tp, 0) == 0) {
		CLR(sc->sc_mcr, sc->sc_dtr);
		bus_space_write_1(iot, ioh, com_mcr, sc->sc_mcr);
	}

	/* Just to be sure... */
	splx(s);
	comstart(tp);
	return 0;
}

void
comstart(tp)
	struct tty *tp;
{
	struct com_softc *sc = com_cd.cd_devs[DEVUNIT(tp->t_dev)];
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;
	int s;

	s = spltty();
	if (ISSET(tp->t_state, TS_BUSY))
		goto out;
	if (ISSET(tp->t_state, TS_TIMEOUT | TS_TTSTOP) || sc->sc_halt > 0)
		goto stopped;
	if (ISSET(tp->t_cflag, CRTSCTS) && !ISSET(sc->sc_msr, MSR_CTS))
		goto stopped;
	if (tp->t_outq.c_cc <= tp->t_lowat) {
		if (ISSET(tp->t_state, TS_ASLEEP)) {
			CLR(tp->t_state, TS_ASLEEP);
			wakeup(&tp->t_outq);
		}
		if (tp->t_outq.c_cc == 0)
			goto stopped;
		selwakeup(&tp->t_wsel);
	}
	SET(tp->t_state, TS_BUSY);

	if (!ISSET(sc->sc_ier, IER_ETXRDY)) {
		SET(sc->sc_ier, IER_ETXRDY);
		bus_space_write_1(iot, ioh, com_ier, sc->sc_ier);
	}
	if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
		u_char buffer[64];	/* XXX: largest fifo */
		u_char *cp = buffer;
		int n = q_to_b(&tp->t_outq, cp, sc->sc_fifolen);
		do {
			bus_space_write_1(iot, ioh, com_data, *cp++);
		} while (--n);
	} else
		bus_space_write_1(iot, ioh, com_data, getc(&tp->t_outq));
out:
	splx(s);
	return;
stopped:
	if (ISSET(sc->sc_ier, IER_ETXRDY)) {
		CLR(sc->sc_ier, IER_ETXRDY);
		bus_space_write_1(iot, ioh, com_ier, sc->sc_ier);
	}
	splx(s);
}

/*
 * Stop output on a line.
 */
int
comstop(tp, flag)
	struct tty *tp;
	int flag;
{
	int s;

	s = spltty();
	if (ISSET(tp->t_state, TS_BUSY))
		if (!ISSET(tp->t_state, TS_TTSTOP))
			SET(tp->t_state, TS_FLUSH);
	splx(s);
	return 0;
}

void
comdiag(arg)
	void *arg;
{
	struct com_softc *sc = arg;
	int overflows, floods;
	int s;

	s = spltty();
	sc->sc_errors = 0;
	overflows = sc->sc_overflows;
	sc->sc_overflows = 0;
	floods = sc->sc_floods;
	sc->sc_floods = 0;
	splx(s);

	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf overflow%s\n",
	    sc->sc_dev.dv_xname,
	    overflows, overflows == 1 ? "" : "s",
	    floods, floods == 1 ? "" : "s");
}

void
compoll(arg)
	void *arg;
{
	int unit;
	struct com_softc *sc;
	struct tty *tp;
	register u_char *ibufp;
	u_char *ibufend;
	register int c;
	int s;
	static int lsrmap[8] = {
		0,      TTY_PE,
		TTY_FE, TTY_PE|TTY_FE,
		TTY_FE, TTY_PE|TTY_FE,
		TTY_FE, TTY_PE|TTY_FE
	};

	s = spltty();
	if (comevents == 0) {
		splx(s);
		goto out;
	}
	comevents = 0;
	splx(s);

	for (unit = 0; unit < com_cd.cd_ndevs; unit++) {
		sc = com_cd.cd_devs[unit];
		if (sc == 0 || sc->sc_ibufp == sc->sc_ibuf)
			continue;

		tp = sc->sc_tty;

		s = spltty();

		ibufp = sc->sc_ibuf;
		ibufend = sc->sc_ibufp;

		if (ibufp == ibufend) {
			splx(s);
			continue;
		}

		sc->sc_ibufp = sc->sc_ibuf = (ibufp == sc->sc_ibufs[0]) ?
					     sc->sc_ibufs[1] : sc->sc_ibufs[0];
		sc->sc_ibufhigh = sc->sc_ibuf + COM_IHIGHWATER;
		sc->sc_ibufend = sc->sc_ibuf + COM_IBUFSIZE;

		if (tp == 0 || !ISSET(tp->t_state, TS_ISOPEN)) {
			splx(s);
			continue;
		}

		if (ISSET(tp->t_cflag, CRTSCTS) &&
		    !ISSET(sc->sc_mcr, MCR_RTS)) {
			/* XXX */
			SET(sc->sc_mcr, MCR_RTS);
			bus_space_write_1(sc->sc_iot, sc->sc_ioh, com_mcr,
			    sc->sc_mcr);
		}

		splx(s);

		while (ibufp < ibufend) {
			c = *ibufp++;
			if (*ibufp & LSR_OE) {
				sc->sc_overflows++;
				if (sc->sc_errors++ == 0)
					timeout(comdiag, sc, 60 * hz);
			}
			/* This is ugly, but fast. */
			c |= lsrmap[(*ibufp++ & (LSR_BI|LSR_FE|LSR_PE)) >> 2];
			(*linesw[tp->t_line].l_rint)(c, tp);
		}
	}

out:
	timeout(compoll, NULL, 1);
}

int
comintr(arg)
	void *arg;
{
	struct com_softc *sc = arg;
	bus_space_tag_t iot = sc->sc_iot;
	bus_space_handle_t ioh = sc->sc_ioh;
	struct tty *tp;
	u_char lsr, data, msr, delta;
#ifdef PPS_SYNC
	struct timeval tv;
	long usec;
#endif /* PPS_SYNC */
#ifdef COM_DEBUG
	int n;
	struct {
		u_char iir, lsr, msr;
	} iter[32];
#endif

	if (!sc->sc_tty)
		return (0);		/* can't do squat. */

#ifdef COM_DEBUG
	n = 0;
	if (ISSET(iter[n].iir = bus_space_read_1(iot, ioh, com_iir), IIR_NOPEND))
		return (0);
#else
	if (ISSET(bus_space_read_1(iot, ioh, com_iir), IIR_NOPEND))
		return (0);
#endif

	tp = sc->sc_tty;

	for (;;) {
#ifdef COM_DEBUG
		iter[n].lsr =
#endif
		lsr = bus_space_read_1(iot, ioh, com_lsr);

		if (ISSET(lsr, LSR_RXRDY)) {
			register u_char *p = sc->sc_ibufp;

			comevents = 1;
			do {
				data = bus_space_read_1(iot, ioh, com_data);
				if (ISSET(lsr, LSR_BI)) {
#ifdef notdef
					printf("break %02x %02x %02x %02x\n",
					    sc->sc_msr, sc->sc_mcr, sc->sc_lcr,
					    sc->sc_dtr);
#endif
#ifdef DDB
					if (ISSET(sc->sc_hwflags,
					    COM_HW_CONSOLE)) {
						if (db_console)
							Debugger();
						goto next;
					}
#endif
					data = 0;
				}
				if (p >= sc->sc_ibufend) {
					sc->sc_floods++;
					if (sc->sc_errors++ == 0)
						timeout(comdiag, sc, 60 * hz);
				} else {
					*p++ = data;
					*p++ = lsr;
					if (p == sc->sc_ibufhigh &&
					    ISSET(tp->t_cflag, CRTSCTS)) {
						/* XXX */
						CLR(sc->sc_mcr, MCR_RTS);
						bus_space_write_1(iot, ioh, com_mcr,
						    sc->sc_mcr);
					}
				}
#ifdef DDB
			next:
#endif
#ifdef COM_DEBUG
				if (++n >= 32)
					goto ohfudge;
				iter[n].lsr =
#endif
				lsr = bus_space_read_1(iot, ioh, com_lsr);
			} while (ISSET(lsr, LSR_RXRDY));

			sc->sc_ibufp = p;
		}
#ifdef COM_DEBUG
		else if (ISSET(lsr, LSR_BI|LSR_FE|LSR_PE|LSR_OE))
			printf("weird lsr %02x\n", lsr);
#endif

#ifdef COM_DEBUG
		iter[n].msr =
#endif
		msr = bus_space_read_1(iot, ioh, com_msr);

		if (msr != sc->sc_msr) {
			delta = msr ^ sc->sc_msr;
			sc->sc_msr = msr;
			if (ISSET(delta, MSR_DCD)) {
#ifdef PPS_SYNC
				if (ISSET(sc->sc_swflags, COM_SW_PPS)) {
					if (ISSET(msr, MSR_DCD)) {
						usec = time.tv_usec;
						microtime(&tv);
						usec = tv.tv_usec - usec;
						if (usec < 0)
							usec += 1000000;
						hardpps(&tv, usec);
					}
				}
				else
#endif /* PPS_SYNC */
				if (!ISSET(sc->sc_swflags, COM_SW_SOFTCAR) &&
				    (*linesw[tp->t_line].l_modem)(tp, ISSET(msr, MSR_DCD)) == 0) {
					CLR(sc->sc_mcr, sc->sc_dtr);
					bus_space_write_1(iot, ioh, com_mcr, sc->sc_mcr);
				}
			}
			if (ISSET(delta & msr, MSR_CTS) &&
			    ISSET(tp->t_cflag, CRTSCTS)) {
				/* the line is up and we want to do rts/cts flow control */
				(*linesw[tp->t_line].l_start)(tp);
			}
		}

		if (ISSET(lsr, LSR_TXRDY) && ISSET(tp->t_state, TS_BUSY)) {
			CLR(tp->t_state, TS_BUSY | TS_FLUSH);
			if (sc->sc_halt > 0)
				wakeup(&tp->t_outq);
			(*linesw[tp->t_line].l_start)(tp);
		}

#ifdef COM_DEBUG
		if (++n >= 32)
			goto ohfudge;
		if (ISSET(iter[n].iir = bus_space_read_1(iot, ioh, com_iir), IIR_NOPEND))
			return (1);
#else
		if (ISSET(bus_space_read_1(iot, ioh, com_iir), IIR_NOPEND))
			return (1);
#endif
	}
#ifdef COM_DEBUG
ohfudge:
	printf("comintr: too many iterations");
	for (n = 0; n < 32; n++) {
		if ((n % 4) == 0)
			printf("\ncomintr: iter[%02d]", n);
		printf("  %02x %02x %02x", iter[n].iir, iter[n].lsr, iter[n].msr);
	}
	printf("\n");
	printf("comintr: msr %02x mcr %02x lcr %02x ier %02x\n",
	    sc->sc_msr, sc->sc_mcr, sc->sc_lcr, sc->sc_ier);
	printf("comintr: state %08x cc %d\n", sc->sc_tty->t_state,
	    sc->sc_tty->t_outq.c_cc);
#endif
}

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

#ifdef arc
#undef CONADDR
	extern int CONADDR;
#endif

void
comcnprobe(cp)
	struct consdev *cp;
{
	/* XXX NEEDS TO BE FIXED XXX */
#ifdef arc
	bus_space_tag_t iot = &arc_bus_io;
#else
#ifdef powerpc
	bus_space_tag_t iot = &p4e_isa_io;
#else
        bus_space_tag_t iot = 0;
#endif   
#endif
	bus_space_handle_t ioh;
	int found;

	if(CONADDR == 0) {
		cp->cn_pri = CN_DEAD;
		return;
	}

	comconsiot = iot;
	if (bus_space_map(iot, CONADDR, COM_NPORTS, 0, &ioh)) {
		cp->cn_pri = CN_DEAD;
		return;
	}
	found = comprobe1(iot, ioh);
	bus_space_unmap(iot, ioh, COM_NPORTS);
	if (!found) {
		cp->cn_pri = CN_DEAD;
		return;
	}

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

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

void
comcninit(cp)
	struct consdev *cp;
{

	if (bus_space_map(comconsiot, CONADDR, COM_NPORTS, 0, &comconsioh))
		panic("comcninit: mapping failed");

	cominit(comconsiot, comconsioh, comdefaultrate);
	comconsaddr = CONADDR;
	comconsinit = 0;
}

void
cominit(iot, ioh, rate)
	bus_space_tag_t iot;
	bus_space_handle_t ioh;
	int rate;
{
	int s = splhigh();
	u_char stat;

	bus_space_write_1(iot, ioh, com_lcr, LCR_DLAB);
	rate = comspeed(comdefaultrate);
	bus_space_write_1(iot, ioh, com_dlbl, rate);
	bus_space_write_1(iot, ioh, com_dlbh, rate >> 8);
	bus_space_write_1(iot, ioh, com_lcr, LCR_8BITS);
	bus_space_write_1(iot, ioh, com_ier, IER_ERXRDY | IER_ETXRDY);
	bus_space_write_1(iot, ioh, com_fifo, FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_4);
	stat = bus_space_read_1(iot, ioh, com_iir);
	splx(s);
}

int
comcngetc(dev)
	dev_t dev;
{
	int s = splhigh();
	bus_space_tag_t iot = comconsiot;
	bus_space_handle_t ioh = comconsioh;
	u_char stat, c;

	while (!ISSET(stat = bus_space_read_1(iot, ioh, com_lsr), LSR_RXRDY))
		;
	c = bus_space_read_1(iot, ioh, com_data);
	stat = bus_space_read_1(iot, ioh, com_iir);
	splx(s);
	return c;
}

/*
 * Console kernel output character routine.
 */
void
comcnputc(dev, c)
	dev_t dev;
	int c;
{
	int s = splhigh();
	bus_space_tag_t iot = comconsiot;
	bus_space_handle_t ioh = comconsioh;
	u_char stat;
	register int timo;

#ifdef KGDB
	if (dev != kgdb_dev)
#endif
	if (comconsinit == 0) {
		cominit(iot, ioh, comdefaultrate);
		comconsinit = 1;
	}
	/* wait for any pending transmission to finish */
	timo = 50000;
	while (!ISSET(stat = bus_space_read_1(iot, ioh, com_lsr), LSR_TXRDY) && --timo)
		;
	bus_space_write_1(iot, ioh, com_data, c);
	/* wait for this transmission to complete */
	timo = 1500000;
	while (!ISSET(stat = bus_space_read_1(iot, ioh, com_lsr), LSR_TXRDY) && --timo)
		;
#if 0 /* I don't think sooooo (pefo) */
	/* clear any interrupts generated by this transmission */
	stat = bus_space_read_1(iot, ioh, com_iir);
#endif
	splx(s);
}

void
comcnpollc(dev, on)
	dev_t dev;
	int on;
{

}