Import sources from 2011-03-30 iso image

1 files changed, 850 insertions, 0 deletions

diff --git a/sys/src/9/omap/uarti8250.c b/sys/src/9/omap/uarti8250.c
new file mode 100755
index 000000000..7642a2685
--- /dev/null
+++ b/sys/src/9/omap/uarti8250.c
@@ -0,0 +1,850 @@
+/*
+ * omap35 8250-like UART
+ *
+ * we ignore the first 2 uarts on the omap35 (see below) and use the
+ * third one but call it 0.
+ */
+
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+
+enum {					/* registers */
+	Rbr		= 0,		/* Receiver Buffer (RO) */
+	Thr		= 0,		/* Transmitter Holding (WO) */
+	Ier		= 1,		/* Interrupt Enable */
+	Iir		= 2,		/* Interrupt Identification (RO) */
+	Fcr		= 2,		/* FIFO Control (WO) */
+	Lcr		= 3,		/* Line Control */
+	Mcr		= 4,		/* Modem Control */
+	Lsr		= 5,		/* Line Status */
+	Msr		= 6,		/* Modem Status */
+	Scr		= 7,		/* Scratch Pad */
+	Mdr		= 8,		/* Mode Def'n (omap rw) */
+//	Usr		= 31,		/* Uart Status Register; missing in omap? */
+	Dll		= 0,		/* Divisor Latch LSB */
+	Dlm		= 1,		/* Divisor Latch MSB */
+};
+
+enum {					/* Usr */
+	Busy		= 0x01,
+};
+
+enum {					/* Ier */
+	Erda		= 0x01,		/* Enable Received Data Available */
+	Ethre		= 0x02,		/* Enable Thr Empty */
+	Erls		= 0x04,		/* Enable Receiver Line Status */
+	Ems		= 0x08,		/* Enable Modem Status */
+};
+
+enum {					/* Iir */
+	Ims		= 0x00,		/* Ms interrupt */
+	Ip		= 0x01,		/* Interrupt Pending (not) */
+	Ithre		= 0x02,		/* Thr Empty */
+	Irda		= 0x04,		/* Received Data Available */
+	Irls		= 0x06,		/* Receiver Line Status */
+	Ictoi		= 0x0C,		/* Character Time-out Indication */
+	IirMASK		= 0x3F,
+	Ifena		= 0xC0,		/* FIFOs enabled */
+};
+
+enum {					/* Fcr */
+	FIFOena		= 0x01,		/* FIFO enable */
+	FIFOrclr	= 0x02,		/* clear Rx FIFO */
+	FIFOtclr	= 0x04,		/* clear Tx FIFO */
+//	FIFOdma		= 0x08,
+	FIFO1		= 0x00,		/* Rx FIFO trigger level 1 byte */
+	FIFO4		= 0x40,		/*	4 bytes */
+	FIFO8		= 0x80,		/*	8 bytes */
+	FIFO14		= 0xC0,		/*	14 bytes */
+};
+
+enum {					/* Lcr */
+	Wls5		= 0x00,		/* Word Length Select 5 bits/byte */
+	Wls6		= 0x01,		/*	6 bits/byte */
+	Wls7		= 0x02,		/*	7 bits/byte */
+	Wls8		= 0x03,		/*	8 bits/byte */
+	WlsMASK		= 0x03,
+	Stb		= 0x04,		/* 2 stop bits */
+	Pen		= 0x08,		/* Parity Enable */
+	Eps		= 0x10,		/* Even Parity Select */
+	Stp		= 0x20,		/* Stick Parity */
+	Brk		= 0x40,		/* Break */
+	Dlab		= 0x80,		/* Divisor Latch Access Bit */
+};
+
+enum {					/* Mcr */
+	Dtr		= 0x01,		/* Data Terminal Ready */
+	Rts		= 0x02,		/* Ready To Send */
+	Out1		= 0x04,		/* no longer in use */
+//	Ie		= 0x08,		/* IRQ Enable (cd_sts_ch on omap) */
+	Dm		= 0x10,		/* Diagnostic Mode loopback */
+};
+
+enum {					/* Lsr */
+	Dr		= 0x01,		/* Data Ready */
+	Oe		= 0x02,		/* Overrun Error */
+	Pe		= 0x04,		/* Parity Error */
+	Fe		= 0x08,		/* Framing Error */
+	Bi		= 0x10,		/* Break Interrupt */
+	Thre		= 0x20,		/* Thr Empty */
+	Temt		= 0x40,		/* Transmitter Empty */
+	FIFOerr		= 0x80,		/* error in receiver FIFO */
+};
+
+enum {					/* Msr */
+	Dcts		= 0x01,		/* Delta Cts */
+	Ddsr		= 0x02,		/* Delta Dsr */
+	Teri		= 0x04,		/* Trailing Edge of Ri */
+	Ddcd		= 0x08,		/* Delta Dcd */
+	Cts		= 0x10,		/* Clear To Send */
+	Dsr		= 0x20,		/* Data Set Ready */
+	Ri		= 0x40,		/* Ring Indicator */
+	Dcd		= 0x80,		/* Carrier Detect */
+};
+
+enum {					/* Mdr */
+	Modemask	= 7,
+	Modeuart	= 0,
+};
+
+
+typedef struct Ctlr {
+	u32int*	io;
+	int	irq;
+	int	tbdf;
+	int	iena;
+	int	poll;
+
+	uchar	sticky[Scr+1];
+
+	Lock;
+	int	hasfifo;
+	int	checkfifo;
+	int	fena;
+} Ctlr;
+
+extern PhysUart i8250physuart;
+
+static Ctlr i8250ctlr[] = {
+{	.io	= (u32int*)PHYSCONS,		/* UART3 in TI terminology */
+	.irq	= 74,
+	.tbdf	= -1,
+	.poll	= 0, },
+
+/* these exist, but I don't think they're connected to anything external */
+//{	.io	= (u32int*)PHYSUART0,
+//	.irq	= 72,
+//	.tbdf	= -1,
+//	.poll	= 0, },
+//
+//{	.io	= (u32int*)PHYSUART1,
+//	.irq	= 73,
+//	.tbdf	= -1,
+//	.poll	= 0, },
+};
+
+static Uart i8250uart[] = {
+{	.regs	= &i8250ctlr[0], /* not [2] */
+	.name	= "COM3",
+	.freq	= 3686000,	/* Not used, we use the global i8250freq */
+	.phys	= &i8250physuart,
+	.console= 1,
+	.next	= nil, },
+
+/* these exist, but I don't think they're connected to anything external */
+//{	.regs	= &i8250ctlr[0],
+//	.name	= "COM1",
+//	.freq	= 3686000,	/* Not used, we use the global i8250freq */
+//	.phys	= &i8250physuart,
+//	.special= 0,
+//	.next	= &i8250uart[1], },
+//
+//{	.regs	= &i8250ctlr[1],
+//	.name	= "COM2",
+//	.freq	= 3686000,	/* Not used, we use the global i8250freq */
+//	.phys	= &i8250physuart,
+//	.special= 0,
+//	.next	= &i8250uart[2], },
+};
+
+#define csr8r(c, r)	((c)->io[r])
+#define csr8w(c, r, v)	((c)->io[r] = (c)->sticky[r] | (v), coherence())
+#define csr8o(c, r, v)	((c)->io[r] = (v), coherence())
+
+static long
+i8250status(Uart* uart, void* buf, long n, long offset)
+{
+	char *p;
+	Ctlr *ctlr;
+	uchar ier, lcr, mcr, msr;
+
+	ctlr = uart->regs;
+	p = malloc(READSTR);
+	mcr = ctlr->sticky[Mcr];
+	msr = csr8r(ctlr, Msr);
+	ier = ctlr->sticky[Ier];
+	lcr = ctlr->sticky[Lcr];
+	snprint(p, READSTR,
+		"b%d c%d d%d e%d l%d m%d p%c r%d s%d i%d\n"
+		"dev(%d) type(%d) framing(%d) overruns(%d) "
+		"berr(%d) serr(%d)%s%s%s%s\n",
+
+		uart->baud,
+		uart->hup_dcd,
+		(msr & Dsr) != 0,
+		uart->hup_dsr,
+		(lcr & WlsMASK) + 5,
+		(ier & Ems) != 0,
+		(lcr & Pen) ? ((lcr & Eps) ? 'e': 'o'): 'n',
+		(mcr & Rts) != 0,
+		(lcr & Stb) ? 2: 1,
+		ctlr->fena,
+
+		uart->dev,
+		uart->type,
+		uart->ferr,
+		uart->oerr,
+		uart->berr,
+		uart->serr,
+		(msr & Cts) ? " cts": "",
+		(msr & Dsr) ? " dsr": "",
+		(msr & Dcd) ? " dcd": "",
+		(msr & Ri) ? " ring": ""
+	);
+	n = readstr(offset, buf, n, p);
+	free(p);
+
+	return n;
+}
+
+static void
+i8250fifo(Uart* uart, int level)
+{
+	Ctlr *ctlr;
+
+	ctlr = uart->regs;
+	if(ctlr->hasfifo == 0)
+		return;
+
+	/*
+	 * Changing the FIFOena bit in Fcr flushes data
+	 * from both receive and transmit FIFOs; there's
+	 * no easy way to guarantee not losing data on
+	 * the receive side, but it's possible to wait until
+	 * the transmitter is really empty.
+	 */
+	ilock(ctlr);
+	while(!(csr8r(ctlr, Lsr) & Temt))
+		;
+
+	/*
+	 * Set the trigger level, default is the max.
+	 * value.
+	 * Some UARTs require FIFOena to be set before
+	 * other bits can take effect, so set it twice.
+	 */
+	ctlr->fena = level;
+	switch(level){
+	case 0:
+		break;
+	case 1:
+		level = FIFO1|FIFOena;
+		break;
+	case 4:
+		level = FIFO4|FIFOena;
+		break;
+	case 8:
+		level = FIFO8|FIFOena;
+		break;
+	default:
+		level = FIFO14|FIFOena;
+		break;
+	}
+	csr8w(ctlr, Fcr, level);
+	csr8w(ctlr, Fcr, level);
+	iunlock(ctlr);
+}
+
+static void
+i8250dtr(Uart* uart, int on)
+{
+	Ctlr *ctlr;
+
+	/*
+	 * Toggle DTR.
+	 */
+	ctlr = uart->regs;
+	if(on)
+		ctlr->sticky[Mcr] |= Dtr;
+	else
+		ctlr->sticky[Mcr] &= ~Dtr;
+	csr8w(ctlr, Mcr, 0);
+}
+
+static void
+i8250rts(Uart* uart, int on)
+{
+	Ctlr *ctlr;
+
+	/*
+	 * Toggle RTS.
+	 */
+	ctlr = uart->regs;
+	if(on)
+		ctlr->sticky[Mcr] |= Rts;
+	else
+		ctlr->sticky[Mcr] &= ~Rts;
+	csr8w(ctlr, Mcr, 0);
+}
+
+static void
+i8250modemctl(Uart* uart, int on)
+{
+	Ctlr *ctlr;
+
+	ctlr = uart->regs;
+	ilock(&uart->tlock);
+	if(on){
+		ctlr->sticky[Ier] |= Ems;
+		csr8w(ctlr, Ier, 0);
+		uart->modem = 1;
+		uart->cts = csr8r(ctlr, Msr) & Cts;
+	}
+	else{
+		ctlr->sticky[Ier] &= ~Ems;
+		csr8w(ctlr, Ier, 0);
+		uart->modem = 0;
+		uart->cts = 1;
+	}
+	iunlock(&uart->tlock);
+
+	/* modem needs fifo */
+	(*uart->phys->fifo)(uart, on);
+}
+
+static int
+i8250parity(Uart* uart, int parity)
+{
+	int lcr;
+	Ctlr *ctlr;
+
+	ctlr = uart->regs;
+	lcr = ctlr->sticky[Lcr] & ~(Eps|Pen);
+
+	switch(parity){
+	case 'e':
+		lcr |= Eps|Pen;
+		break;
+	case 'o':
+		lcr |= Pen;
+		break;
+	case 'n':
+		break;
+	default:
+		return -1;
+	}
+	ctlr->sticky[Lcr] = lcr;
+	csr8w(ctlr, Lcr, 0);
+
+	uart->parity = parity;
+
+	return 0;
+}
+
+static int
+i8250stop(Uart* uart, int stop)
+{
+	int lcr;
+	Ctlr *ctlr;
+
+	ctlr = uart->regs;
+	lcr = ctlr->sticky[Lcr] & ~Stb;
+
+	switch(stop){
+	case 1:
+		break;
+	case 2:
+		lcr |= Stb;
+		break;
+	default:
+		return -1;
+	}
+	ctlr->sticky[Lcr] = lcr;
+	csr8w(ctlr, Lcr, 0);
+
+	uart->stop = stop;
+
+	return 0;
+}
+
+static int
+i8250bits(Uart* uart, int bits)
+{
+	int lcr;
+	Ctlr *ctlr;
+
+	ctlr = uart->regs;
+	lcr = ctlr->sticky[Lcr] & ~WlsMASK;
+
+	switch(bits){
+	case 5:
+		lcr |= Wls5;
+		break;
+	case 6:
+		lcr |= Wls6;
+		break;
+	case 7:
+		lcr |= Wls7;
+		break;
+	case 8:
+		lcr |= Wls8;
+		break;
+	default:
+		return -1;
+	}
+	ctlr->sticky[Lcr] = lcr;
+	csr8w(ctlr, Lcr, 0);
+
+	uart->bits = bits;
+
+	return 0;
+}
+
+static int
+i8250baud(Uart* uart, int baud)
+{
+#ifdef notdef				/* don't change the speed */
+	ulong bgc;
+	Ctlr *ctlr;
+	extern int i8250freq;	/* In the config file */
+
+	/*
+	 * Set the Baud rate by calculating and setting the Baud rate
+	 * Generator Constant. This will work with fairly non-standard
+	 * Baud rates.
+	 */
+	if(i8250freq == 0 || baud <= 0)
+		return -1;
+	bgc = (i8250freq+8*baud-1)/(16*baud);
+
+	ctlr = uart->regs;
+	while(csr8r(ctlr, Usr) & Busy)
+		delay(1);
+	csr8w(ctlr, Lcr, Dlab);		/* begin kludge */
+	csr8o(ctlr, Dlm, bgc>>8);
+	csr8o(ctlr, Dll, bgc);
+	csr8w(ctlr, Lcr, 0);
+#endif
+	uart->baud = baud;
+	return 0;
+}
+
+static void
+i8250break(Uart* uart, int ms)
+{
+	Ctlr *ctlr;
+
+	if (up == nil)
+		panic("i8250break: nil up");
+	/*
+	 * Send a break.
+	 */
+	if(ms <= 0)
+		ms = 200;
+
+	ctlr = uart->regs;
+	csr8w(ctlr, Lcr, Brk);
+	tsleep(&up->sleep, return0, 0, ms);
+	csr8w(ctlr, Lcr, 0);
+}
+
+static void
+emptyoutstage(Uart *uart, int n)
+{
+	_uartputs((char *)uart->op, n);
+	uart->op = uart->oe = uart->ostage;
+}
+
+static void
+i8250kick(Uart* uart)
+{
+	int i;
+	Ctlr *ctlr;
+
+	if(/* uart->cts == 0 || */ uart->blocked)
+		return;
+
+	if(!normalprint) {			/* early */
+		if (uart->op < uart->oe)
+			emptyoutstage(uart, uart->oe - uart->op);
+		while ((i = uartstageoutput(uart)) > 0)
+			emptyoutstage(uart, i);
+		return;
+	}
+
+	/* nothing more to send? then disable xmit intr */
+	ctlr = uart->regs;
+	if (uart->op >= uart->oe && qlen(uart->oq) == 0 &&
+	    csr8r(ctlr, Lsr) & Temt) {
+		ctlr->sticky[Ier] &= ~Ethre;
+		csr8w(ctlr, Ier, 0);
+		return;
+	}
+
+	/*
+	 *  128 here is an arbitrary limit to make sure
+	 *  we don't stay in this loop too long.  If the
+	 *  chip's output queue is longer than 128, too
+	 *  bad -- presotto
+	 */
+	for(i = 0; i < 128; i++){
+		if(!(csr8r(ctlr, Lsr) & Thre))
+			break;
+		if(uart->op >= uart->oe && uartstageoutput(uart) == 0)
+			break;
+		csr8o(ctlr, Thr, *uart->op++);		/* start tx */
+		ctlr->sticky[Ier] |= Ethre;
+		csr8w(ctlr, Ier, 0);			/* intr when done */
+	}
+}
+
+void
+serialkick(void)
+{
+	uartkick(&i8250uart[CONSOLE]);
+}
+
+static void
+i8250interrupt(Ureg*, void* arg)
+{
+	Ctlr *ctlr;
+	Uart *uart;
+	int iir, lsr, old, r;
+
+	uart = arg;
+	ctlr = uart->regs;
+	for(iir = csr8r(ctlr, Iir); !(iir & Ip); iir = csr8r(ctlr, Iir)){
+		switch(iir & IirMASK){
+		case Ims:		/* Ms interrupt */
+			r = csr8r(ctlr, Msr);
+			if(r & Dcts){
+				ilock(&uart->tlock);
+				old = uart->cts;
+				uart->cts = r & Cts;
+				if(old == 0 && uart->cts)
+					uart->ctsbackoff = 2;
+				iunlock(&uart->tlock);
+			}
+		 	if(r & Ddsr){
+				old = r & Dsr;
+				if(uart->hup_dsr && uart->dsr && !old)
+					uart->dohup = 1;
+				uart->dsr = old;
+			}
+		 	if(r & Ddcd){
+				old = r & Dcd;
+				if(uart->hup_dcd && uart->dcd && !old)
+					uart->dohup = 1;
+				uart->dcd = old;
+			}
+			break;
+		case Ithre:		/* Thr Empty */
+			uartkick(uart);
+			break;
+		case Irda:		/* Received Data Available */
+		case Irls:		/* Receiver Line Status */
+		case Ictoi:		/* Character Time-out Indication */
+			/*
+			 * Consume any received data.
+			 * If the received byte came in with a break,
+			 * parity or framing error, throw it away;
+			 * overrun is an indication that something has
+			 * already been tossed.
+			 */
+			while((lsr = csr8r(ctlr, Lsr)) & Dr){
+				if(lsr & (FIFOerr|Oe))
+					uart->oerr++;
+				if(lsr & Pe)
+					uart->perr++;
+				if(lsr & Fe)
+					uart->ferr++;
+				r = csr8r(ctlr, Rbr);
+				if(!(lsr & (Bi|Fe|Pe)))
+					uartrecv(uart, r);
+			}
+			break;
+
+		default:
+			iprint("weird uart interrupt type %#2.2uX\n", iir);
+			break;
+		}
+	}
+}
+
+static void
+i8250disable(Uart* uart)
+{
+	Ctlr *ctlr;
+
+	/*
+	 * Turn off DTR and RTS, disable interrupts and fifos.
+	 */
+	(*uart->phys->dtr)(uart, 0);
+	(*uart->phys->rts)(uart, 0);
+	(*uart->phys->fifo)(uart, 0);
+
+	ctlr = uart->regs;
+	ctlr->sticky[Ier] = 0;
+	csr8w(ctlr, Ier, 0);
+
+	if(ctlr->iena != 0){
+		if(irqdisable(ctlr->irq, i8250interrupt, uart, uart->name) == 0)
+			ctlr->iena = 0;
+	}
+}
+
+static void
+i8250enable(Uart* uart, int ie)
+{
+	int mode;
+	Ctlr *ctlr;
+
+	if (up == nil)
+		return;				/* too soon */
+
+	ctlr = uart->regs;
+
+	/* omap only: set uart/irda/cir mode to uart */
+	mode = csr8r(ctlr, Mdr);
+	csr8o(ctlr, Mdr, (mode & ~Modemask) | Modeuart);
+
+	ctlr->sticky[Lcr] = Wls8;		/* no parity */
+	csr8w(ctlr, Lcr, 0);
+
+	/*
+	 * Check if there is a FIFO.
+	 * Changing the FIFOena bit in Fcr flushes data
+	 * from both receive and transmit FIFOs; there's
+	 * no easy way to guarantee not losing data on
+	 * the receive side, but it's possible to wait until
+	 * the transmitter is really empty.
+	 * Also, reading the Iir outwith i8250interrupt()
+	 * can be dangerous, but this should only happen
+	 * once, before interrupts are enabled.
+	 */
+	ilock(ctlr);
+	if(!ctlr->checkfifo){
+		/*
+		 * Wait until the transmitter is really empty.
+		 */
+		while(!(csr8r(ctlr, Lsr) & Temt))
+			;
+		csr8w(ctlr, Fcr, FIFOena);
+		if(csr8r(ctlr, Iir) & Ifena)
+			ctlr->hasfifo = 1;
+		csr8w(ctlr, Fcr, 0);
+		ctlr->checkfifo = 1;
+	}
+	iunlock(ctlr);
+
+	/*
+	 * Enable interrupts and turn on DTR and RTS.
+	 * Be careful if this is called to set up a polled serial line
+	 * early on not to try to enable interrupts as interrupt-
+	 * -enabling mechanisms might not be set up yet.
+	 */
+	if(ie){
+		if(ctlr->iena == 0 && !ctlr->poll){
+			irqenable(ctlr->irq, i8250interrupt, uart, uart->name);
+			ctlr->iena = 1;
+		}
+		ctlr->sticky[Ier] = Erda;
+//		ctlr->sticky[Mcr] |= Ie;		/* not on omap */
+		ctlr->sticky[Mcr] = 0;
+	}
+	else{
+		ctlr->sticky[Ier] = 0;
+		ctlr->sticky[Mcr] = 0;
+	}
+	csr8w(ctlr, Ier, 0);
+	csr8w(ctlr, Mcr, 0);
+
+	(*uart->phys->dtr)(uart, 1);
+	(*uart->phys->rts)(uart, 1);
+
+	/*
+	 * During startup, the i8259 interrupt controller is reset.
+	 * This may result in a lost interrupt from the i8250 uart.
+	 * The i8250 thinks the interrupt is still outstanding and does not
+	 * generate any further interrupts. The workaround is to call the
+	 * interrupt handler to clear any pending interrupt events.
+	 * Note: this must be done after setting Ier.
+	 */
+	if(ie)
+		i8250interrupt(nil, uart);
+}
+
+static Uart*
+i8250pnp(void)
+{
+	return i8250uart;
+}
+
+static int
+i8250getc(Uart* uart)
+{
+	Ctlr *ctlr;
+
+	ctlr = uart->regs;
+	while(!(csr8r(ctlr, Lsr) & Dr))
+		delay(1);
+	return csr8r(ctlr, Rbr);
+}
+
+static void
+i8250putc(Uart* uart, int c)
+{
+	int i;
+	Ctlr *ctlr;
+
+	if (!normalprint) {		/* too early; use brute force */
+		int s = splhi();
+
+		while (!(((ulong *)PHYSCONS)[Lsr] & Thre))
+			;
+		((ulong *)PHYSCONS)[Thr] = c;
+		coherence();
+		splx(s);
+		return;
+	}
+
+	ctlr = uart->regs;
+	for(i = 0; !(csr8r(ctlr, Lsr) & Thre) && i < 128; i++)
+		delay(1);
+	csr8o(ctlr, Thr, (uchar)c);
+	for(i = 0; !(csr8r(ctlr, Lsr) & Thre) && i < 128; i++)
+		delay(1);
+}
+
+void
+serialputc(int c)
+{
+	i8250putc(&i8250uart[CONSOLE], c);
+}
+
+void
+serialputs(char* s, int n)
+{
+	_uartputs(s, n);
+}
+
+#ifdef notdef
+static void
+i8250poll(Uart* uart)
+{
+	Ctlr *ctlr;
+
+	/*
+	 * If PhysUart has a non-nil .poll member, this
+	 * routine will be called from the uartclock timer.
+	 * If the Ctlr .poll member is non-zero, when the
+	 * Uart is enabled interrupts will not be enabled
+	 * and the result is polled input and output.
+	 * Not very useful here, but ports to new hardware
+	 * or simulators can use this to get serial I/O
+	 * without setting up the interrupt mechanism.
+	 */
+	ctlr = uart->regs;
+	if(ctlr->iena || !ctlr->poll)
+		return;
+	i8250interrupt(nil, uart);
+}
+#endif
+
+PhysUart i8250physuart = {
+	.name		= "i8250",
+	.pnp		= i8250pnp,
+	.enable		= i8250enable,
+	.disable	= i8250disable,
+	.kick		= i8250kick,
+	.dobreak	= i8250break,
+	.baud		= i8250baud,
+	.bits		= i8250bits,
+	.stop		= i8250stop,
+	.parity		= i8250parity,
+	.modemctl	= i8250modemctl,
+	.rts		= i8250rts,
+	.dtr		= i8250dtr,
+	.status		= i8250status,
+	.fifo		= i8250fifo,
+	.getc		= i8250getc,
+	.putc		= i8250putc,
+//	.poll		= i8250poll,		/* only in 9k, not 9 */
+};
+
+static void
+i8250dumpregs(Ctlr* ctlr)
+{
+	int dlm, dll;
+	int _uartprint(char*, ...);
+
+	csr8w(ctlr, Lcr, Dlab);
+	dlm = csr8r(ctlr, Dlm);
+	dll = csr8r(ctlr, Dll);
+	csr8w(ctlr, Lcr, 0);
+
+	_uartprint("dlm %#ux dll %#ux\n", dlm, dll);
+}
+
+Uart*	uartenable(Uart *p);
+
+/* must call this from a process's context */
+int
+i8250console(void)
+{
+	Uart *uart = &i8250uart[CONSOLE];
+
+	if (up == nil)
+		return -1;			/* too early */
+
+	if(uartenable(uart) != nil /* && uart->console */){
+		// iprint("i8250console: enabling console uart\n");
+		kbdq = uart->iq;
+		serialoq = uart->oq;
+		uart->putc = kbdcr2nl;
+		uart->opens++;
+		consuart = uart;
+	}
+	uartctl(uart, "b115200 l8 pn r1 s1 i1");
+	return 0;
+}
+
+void
+_uartputs(char* s, int n)
+{
+	char *e;
+
+	for(e = s+n; s < e; s++){
+		if(*s == '\n')
+			i8250putc(&i8250uart[CONSOLE], '\r');
+		i8250putc(&i8250uart[CONSOLE], *s);
+	}
+}
+
+int
+_uartprint(char* fmt, ...)
+{
+	int n;
+	va_list arg;
+	char buf[PRINTSIZE];
+
+	va_start(arg, fmt);
+	n = vseprint(buf, buf+sizeof(buf), fmt, arg) - buf;
+	va_end(arg);
+	_uartputs(buf, n);
+
+	return n;
+}