xref: /src/sys/dev/isa/isa.c

/*-
 * Copyright (c) 1993, 1994 Charles Hannum.
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	from: @(#)isa.c	7.2 (Berkeley) 5/13/91
 *	$Id: isa.c,v 1.46 1994/03/29 04:34:18 mycroft Exp $
 */

/*
 * code to manage AT bus
 *
 * 92/08/18  Frank P. MacLachlan (fpm (at) crash.cts.com):
 * Fixed uninitialized variable problem and added code to deal
 * with DMA page boundaries in isa_dmarangecheck().  Fixed word
 * mode DMA count compution and reorganized DMA setup code in
 * isa_dmastart()
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/buf.h>
#include <sys/uio.h>
#include <sys/syslog.h>
#include <sys/malloc.h>
#include <sys/device.h>

#include <vm/vm.h>

#include <machine/segments.h>
#include <machine/pio.h>
#include <machine/cpufunc.h>

#include <i386/isa/isa.h>
#include <i386/isa/isa_device.h>
#include <i386/isa/isavar.h>
#include <i386/isa/icu.h>
#include <i386/isa/ic/i8237.h>
#include <i386/isa/ic/i8042.h>
#include <i386/isa/timerreg.h>
#include <i386/isa/spkr_reg.h>

/* sorry, has to be here, no place else really suitable */
#include <machine/pc/display.h>
u_short *Crtat = (u_short *)MONO_BUF;

/*
 * Register definitions for DMA controller 1 (channels 0..3):
 */
#define	DMA1_CHN(c)	(IO_DMA1 + 1*(2*(c)))	/* addr reg for channel c */
#define	DMA1_SR		(IO_DMA1 + 1*8)		/* status register */
#define	DMA1_SMSK	(IO_DMA1 + 1*10)	/* single mask register */
#define	DMA1_MODE	(IO_DMA1 + 1*11)	/* mode register */
#define	DMA1_FFC	(IO_DMA1 + 1*12)	/* clear first/last FF */

/*
 * Register definitions for DMA controller 2 (channels 4..7):
 */
#define	DMA2_CHN(c)	(IO_DMA2 + 2*(2*(c)))	/* addr reg for channel c */
#define	DMA2_SR		(IO_DMA2 + 2*8)		/* status register */
#define	DMA2_SMSK	(IO_DMA2 + 2*10)	/* single mask register */
#define	DMA2_MODE	(IO_DMA2 + 2*11)	/* mode register */
#define	DMA2_FFC	(IO_DMA2 + 2*12)	/* clear first/last FF */

static void sysbeepstop(int);

/*
 * Configure all ISA devices
 *
 * XXX This code is a hack.  It wants to be new config, but can't be until the
 * interrupt system is redone.  For now, we do some gross hacks to make it look
 * 99% like new config.
 */
static char *msgs[3] = { "", " not configured\n", " unsupported\n" };

struct cfdata *
config_search(fn, parent, aux)
	cfmatch_t fn;
	struct device *parent;
	void *aux;
{
	struct cfdata *cf = 0;
	struct device *dv = 0;
	size_t devsize;
	struct cfdriver *cd;
	struct isa_device *id,
	    *idp =  parent ? (void *)parent->dv_cfdata->cf_loc : 0;

	for (id = isa_devtab; id->id_driver; id++) {
		if (id->id_state == FSTATE_FOUND)
			continue;
		if (id->id_parent != idp)
			continue;
		cd = id->id_driver;
		if (id->id_unit < cd->cd_ndevs) {
			if (cd->cd_devs[id->id_unit] != 0)
				continue;
		} else {
			int old = cd->cd_ndevs, new;
			void **nsp;

			if (old == 0) {
				nsp = malloc(MINALLOCSIZE, M_DEVBUF, M_NOWAIT);
				if (!nsp)
					panic("config_search: creating dev array");
				bzero(nsp, MINALLOCSIZE);
				cd->cd_ndevs = MINALLOCSIZE / sizeof(void *);
			} else {
				new = old;
				do {
					new *= 2;
				} while (new <= id->id_unit);
				cd->cd_ndevs = new;
				nsp = malloc(new * sizeof(void *), M_DEVBUF,
				    M_NOWAIT);
				if (!nsp)
					panic("config_search: expanding dev array");
				bzero(nsp, new * sizeof(void *));
				bcopy(cd->cd_devs, nsp, old * sizeof(void *));
				free(cd->cd_devs, M_DEVBUF);
			}
			cd->cd_devs = nsp;
		}
		if (!cf) {
			cf = malloc(sizeof(struct cfdata), M_DEVBUF, M_NOWAIT);				if (!cf)
				panic("config_search: creating cfdata");
		}
		cf->cf_driver = cd;
		cf->cf_unit = id->id_unit;
		cf->cf_fstate = 0;
		cf->cf_loc = (void *)id;
		cf->cf_flags = id->id_flags;
		cf->cf_parents = 0;
		cf->cf_ivstubs = 0;
		if (dv && devsize != cd->cd_devsize) {
			free(dv, M_DEVBUF);
			dv = 0;
		}
		if (!dv) {
			devsize = cd->cd_devsize;
			dv = malloc(devsize, M_DEVBUF, M_NOWAIT);
			if (!dv)
				panic("config_search: creating softc");
		}
		bzero(dv, cd->cd_devsize);
		dv->dv_class = cd->cd_class;
		dv->dv_cfdata = cf;
		dv->dv_unit = id->id_unit;
		sprintf(dv->dv_xname, "%s%d", cd->cd_name, id->id_unit);
		dv->dv_parent = parent;
		cd->cd_devs[id->id_unit] = dv;
		if (fn) {
			if ((*fn)(parent, dv, aux))
				return cf;
		} else {
			if ((*cd->cd_match)(parent, dv, aux))
				return cf;
		}
		if (id->id_state == FSTATE_FOUND) {
			cf = 0;
			dv = 0;
		} else
			cd->cd_devs[id->id_unit] = 0;
	}
	if (cf)
		free(cf, M_DEVBUF);
	if (dv)
		free(dv, M_DEVBUF);
	return 0;
}

void
config_attach(parent, cf, aux, print)
	struct device *parent;
	struct cfdata *cf;
	void *aux;
	cfprint_t print;
{
	struct isa_device *id = (void *)cf->cf_loc;
	struct cfdriver *cd = cf->cf_driver;
	struct device *dv = cd->cd_devs[id->id_unit];

	cf->cf_fstate = id->id_state = FSTATE_FOUND;
	printf("%s at %s", dv->dv_xname, parent ? parent->dv_xname : "isa0");
	if (print)
		(void) (*print)(aux, (char *)0);
	(*cd->cd_attach)(parent, dv, aux);
}

int
config_found(parent, aux, print)
	struct device *parent;
	void *aux;
	cfprint_t print;
{
	struct cfdata *cf;

	if ((cf = config_search((cfmatch_t)NULL, parent, aux)) != NULL) {
		config_attach(parent, cf, aux, print);
		return 1;
	}
	if (print)
		printf(msgs[(*print)(aux, parent->dv_xname)]);
	return 0;
}

int
isaprint(aux, isa)
	void *aux;
	char *isa;
{
	struct isa_attach_args *ia = aux;

	if (ia->ia_iosize)
		printf(" port 0x%x", ia->ia_iobase);
	if (ia->ia_iosize > 1)
		printf("-0x%x", ia->ia_iobase + ia->ia_iosize - 1);
	if (ia->ia_msize)
		printf(" iomem 0x%x", ia->ia_maddr - atdevbase + 0xa0000);
	if (ia->ia_msize > 1)
		printf("-0x%x",
		    ia->ia_maddr - atdevbase + 0xa0000 + ia->ia_msize - 1);
	if (ia->ia_irq)
		printf(" irq %d", ffs(ia->ia_irq) - 1);
	if (ia->ia_drq != (u_short)-1)
		printf(" drq %d", ia->ia_drq);
	/* XXXX print flags */
	return QUIET;
}

int
isasubmatch(parent, self, aux)
	struct device *parent, *self;
	void *aux;
{
	struct isa_device *id = (void *)self->dv_cfdata->cf_loc;
	struct isa_attach_args ia;

	ia.ia_iobase = id->id_iobase;
	ia.ia_iosize = 0x666;
	ia.ia_irq = id->id_irq;
	ia.ia_drq = id->id_drq;
	ia.ia_maddr = id->id_maddr - 0xa0000 + atdevbase;
	ia.ia_msize = id->id_msize;

	if (!(*id->id_driver->cd_match)(parent, self, &ia)) {
		/*
		 * If we don't do this, isa_configure() will repeatedly try to
		 * probe devices that weren't found.  But we need to be careful
		 * to do it only for the ISA bus, or we would cause things like
		 * `com0 at ast? slave ?' to not probe on the second ast.
		 */
		if (!parent)
			id->id_state = FSTATE_FOUND;

		return 0;
	}

	config_attach(parent, self->dv_cfdata, &ia, isaprint);

	if (id->id_irq) {
		int intrno;

		intrno = ffs(id->id_irq) - 1;
		setidt(ICU_OFFSET+intrno, id->id_intr, SDT_SYS386IGT, SEL_KPL);
		if (id->id_mask)
			INTRMASK(*id->id_mask, id->id_irq);
		INTREN(id->id_irq);
	}

	return 1;
}

void
isa_configure()
{

	splhigh();
	INTREN(IRQ_SLAVE);
	enable_intr();

	while (config_search(isasubmatch, NULL, NULL));

	printf("biomask %x ttymask %x netmask %x\n",
	       biomask, ttymask, netmask);

	clockmask |= astmask;
	biomask |= astmask;
	ttymask |= astmask;
	netmask |= astmask;
	impmask = netmask | ttymask;

	spl0();
}

#define	IDTVEC(name)	__CONCAT(X,name)
/* default interrupt vector table entries */
extern	IDTVEC(intr0), IDTVEC(intr1), IDTVEC(intr2), IDTVEC(intr3),
	IDTVEC(intr4), IDTVEC(intr5), IDTVEC(intr6), IDTVEC(intr7),
	IDTVEC(intr8), IDTVEC(intr9), IDTVEC(intr10), IDTVEC(intr11),
	IDTVEC(intr12), IDTVEC(intr13), IDTVEC(intr14), IDTVEC(intr15);

static *defvec[16] = {
	&IDTVEC(intr0), &IDTVEC(intr1), &IDTVEC(intr2), &IDTVEC(intr3),
	&IDTVEC(intr4), &IDTVEC(intr5), &IDTVEC(intr6), &IDTVEC(intr7),
	&IDTVEC(intr8), &IDTVEC(intr9), &IDTVEC(intr10), &IDTVEC(intr11),
	&IDTVEC(intr12), &IDTVEC(intr13), &IDTVEC(intr14), &IDTVEC(intr15) };

/* out of range default interrupt vector gate entry */
extern	IDTVEC(intrdefault);

/*
 * Fill in default interrupt table (in case of spuruious interrupt
 * during configuration of kernel, setup interrupt control unit
 */
void
isa_defaultirq() {
	int i;

	/* icu vectors */
	for (i = NRSVIDT ; i < NRSVIDT+ICU_LEN ; i++)
		setidt(i, defvec[i],  SDT_SYS386IGT, SEL_KPL);

	/* out of range vectors */
	for (i = NRSVIDT; i < NIDT; i++)
		setidt(i, &IDTVEC(intrdefault), SDT_SYS386IGT, SEL_KPL);

	/* initialize 8259's */
	outb(IO_ICU1, 0x11);		/* reset; program device, four bytes */
	outb(IO_ICU1+1, NRSVIDT);	/* starting at this vector index */
	outb(IO_ICU1+1, 1<<2);		/* slave on line 2 */
#ifdef AUTO_EOI_1
	outb(IO_ICU1+1, 2 | 1);		/* auto EOI, 8086 mode */
#else
	outb(IO_ICU1+1, 1);		/* 8086 mode */
#endif
	outb(IO_ICU1+1, 0xff);		/* leave interrupts masked */
	outb(IO_ICU1, 0x0a);		/* default to IRR on read */
#ifdef REORDER_IRQ
	outb(IO_ICU1, 0xc0 | (3 - 1));	/* pri order 3-7, 0-2 (com2 first) */
#endif

	outb(IO_ICU2, 0x11);		/* reset; program device, four bytes */
	outb(IO_ICU2+1, NRSVIDT+8);	/* staring at this vector index */
	outb(IO_ICU2+1,2);		/* my slave id is 2 */
#ifdef AUTO_EOI_2
	outb(IO_ICU2+1, 2 | 1);		/* auto EOI, 8086 mode */
#else
	outb(IO_ICU2+1,1);		/* 8086 mode */
#endif
	outb(IO_ICU2+1, 0xff);		/* leave interrupts masked */
	outb(IO_ICU2, 0x0a);		/* default to IRR on read */
}

/* region of physical memory known to be contiguous */
vm_offset_t isaphysmem;
static caddr_t dma_bounce[8];		/* XXX */
static char bounced[8];		/* XXX */
#define MAXDMASZ 512		/* XXX */

/* high byte of address is stored in this port for i-th dma channel */
static short dmapageport[8] =
	{ 0x87, 0x83, 0x81, 0x82, 0x8f, 0x8b, 0x89, 0x8a };

/*
 * isa_dmacascade(): program 8237 DMA controller channel to accept
 * external dma control by a board.
 */
void
isa_dmacascade(chan)
	int chan;
{

#ifdef DIAGNOSTIC
	if (chan < 0 || chan > 7)
		panic("isa_dmacascade: impossible request");
#endif

	/* set dma channel mode, and set dma channel mode */
	if ((chan & 4) == 0) {
		outb(DMA1_MODE, DMA37MD_CASCADE | chan);
		outb(DMA1_SMSK, chan);
	} else {
		outb(DMA2_MODE, DMA37MD_CASCADE | (chan & 3));
		outb(DMA2_SMSK, chan & 3);
	}
}

/*
 * isa_dmastart(): program 8237 DMA controller channel, avoid page alignment
 * problems by using a bounce buffer.
 */
void
isa_dmastart(flags, addr, nbytes, chan)
	int flags;
	caddr_t addr;
	vm_size_t nbytes;
	int chan;
{
	vm_offset_t phys;
	int waport;
	caddr_t newaddr;

#ifdef DIAGNOSTIC
	if (chan < 0 || chan > 7 ||
	    ((chan & 4) ? (nbytes >= (1<<17) || nbytes & 1 || (u_int)addr & 1) :
	    (nbytes >= (1<<16))))
		panic("isa_dmastart: impossible request");
#endif

	if (isa_dmarangecheck(addr, nbytes, chan)) {
		if (dma_bounce[chan] == 0)
			dma_bounce[chan] =
			    /*(caddr_t)malloc(MAXDMASZ, M_TEMP, M_WAITOK);*/
			    (caddr_t) isaphysmem + NBPG*chan;
		bounced[chan] = 1;
		newaddr = dma_bounce[chan];
		*(int *) newaddr = 0;	/* XXX */
		/* copy bounce buffer on write */
		if ((flags & B_READ) == 0)
			bcopy(addr, newaddr, nbytes);
		addr = newaddr;
	}

	/* translate to physical */
	phys = pmap_extract(pmap_kernel(), (vm_offset_t)addr);

	if ((chan & 4) == 0) {
		/*
		 * Program one of DMA channels 0..3.  These are
		 * byte mode channels.
		 */
		/* set dma channel mode, and reset address ff */
		if (flags & B_READ)
			outb(DMA1_MODE, chan | DMA37MD_SINGLE | DMA37MD_WRITE);
		else
			outb(DMA1_MODE, chan | DMA37MD_SINGLE | DMA37MD_READ);
		outb(DMA1_FFC, 0);

		/* send start address */
		waport =  DMA1_CHN(chan);
		outb(waport, phys);
		outb(waport, phys>>8);
		outb(dmapageport[chan], phys>>16);

		/* send count */
		outb(waport + 1, --nbytes);
		outb(waport + 1, nbytes>>8);

		/* unmask channel */
		outb(DMA1_SMSK, chan | DMA37SM_CLEAR);
	} else {
		/*
		 * Program one of DMA channels 4..7.  These are
		 * word mode channels.
		 */
		/* set dma channel mode, and reset address ff */
		if (flags & B_READ)
			outb(DMA2_MODE, (chan & 3) | DMA37MD_SINGLE | DMA37MD_WRITE);
		else
			outb(DMA2_MODE, (chan & 3) | DMA37MD_SINGLE | DMA37MD_READ);
		outb(DMA2_FFC, 0);

		/* send start address */
		waport = DMA2_CHN(chan & 3);
		outb(waport, phys>>1);
		outb(waport, phys>>9);
		outb(dmapageport[chan], phys>>16);

		/* send count */
		nbytes >>= 1;
		outb(waport + 2, --nbytes);
		outb(waport + 2, nbytes>>8);

		/* unmask channel */
		outb(DMA2_SMSK, (chan & 3) | DMA37SM_CLEAR);
	}
}

void
isa_dmaabort(chan)
	int chan;
{

#ifdef DIAGNOSTIC
	if (chan < 0 || chan > 7)
		panic("isa_dmadone: impossible request");
#endif

	bounced[chan] = 0;

	/* mask channel */
	if ((chan & 4) == 0)
		outb(DMA1_SMSK, DMA37SM_SET | chan);
	else
		outb(DMA2_SMSK, DMA37SM_SET | (chan & 3));
}

void
isa_dmadone(flags, addr, nbytes, chan)
	int flags;
	caddr_t addr;
	vm_size_t nbytes;
	int chan;
{
	u_char tc;

#ifdef DIAGNOSTIC
	if (chan < 0 || chan > 7)
		panic("isa_dmadone: impossible request");
#endif

	/* check that the terminal count was reached */
	if ((chan & 4) == 0)
		tc = inb(DMA1_SR) & (1 << chan);
	else
		tc = inb(DMA2_SR) & (1 << (chan & 3));
	if (tc == 0)
		/* XXX probably should panic or something */
		log(LOG_ERR, "dma channel %d not finished\n", chan);

	/* copy bounce buffer on read */
	if (bounced[chan]) {
		bcopy(dma_bounce[chan], addr, nbytes);
		bounced[chan] = 0;
	}

	/* mask channel */
	if ((chan & 4) == 0)
		outb(DMA1_SMSK, DMA37SM_SET | chan);
	else
		outb(DMA2_SMSK, DMA37SM_SET | (chan & 3));
}

/*
 * Check for problems with the address range of a DMA transfer
 * (non-contiguous physical pages, outside of bus address space,
 * crossing DMA page boundaries).
 * Return true if special handling needed.
 */
int
isa_dmarangecheck(va, length, chan)
	vm_offset_t va;
	u_long length;
	int chan;
{
	vm_offset_t phys, priorpage = 0, endva;
	u_int dma_pgmsk = (chan & 4) ?  ~(128*1024-1) : ~(64*1024-1);

	endva = round_page(va + length);
	for (; va < endva ; va += NBPG) {
		phys = trunc_page(pmap_extract(pmap_kernel(), va));
		if (phys == 0)
			panic("isa_dmacheck: no physical page present");
		if (phys >= (1<<24))
			return 1;
		if (priorpage) {
			if (priorpage + NBPG != phys)
				return 1;
			/* check if crossing a DMA page boundary */
			if ((priorpage ^ phys) & dma_pgmsk)
				return 1;
		}
		priorpage = phys;
	}
	return 0;
}

/* head of queue waiting for physmem to become available */
struct buf isa_physmemq;

/* blocked waiting for resource to become free for exclusive use */
static isaphysmemflag;
/* if waited for and call requested when free (B_CALL) */
static void (*isaphysmemunblock)(); /* needs to be a list */

/*
 * Allocate contiguous physical memory for transfer, returning
 * a *virtual* address to region. May block waiting for resource.
 * (assumed to be called at splbio())
 */
caddr_t
isa_allocphysmem(caddr_t va, unsigned length, void (*func)()) {

	isaphysmemunblock = func;
	while (isaphysmemflag & B_BUSY) {
		isaphysmemflag |= B_WANTED;
		sleep((caddr_t)&isaphysmemflag, PRIBIO);
	}
	isaphysmemflag |= B_BUSY;

	return((caddr_t)isaphysmem);
}

/*
 * Free contiguous physical memory used for transfer.
 * (assumed to be called at splbio())
 */
void
isa_freephysmem(caddr_t va, unsigned length) {

	isaphysmemflag &= ~B_BUSY;
	if (isaphysmemflag & B_WANTED) {
		isaphysmemflag &= B_WANTED;
		wakeup((caddr_t)&isaphysmemflag);
		if (isaphysmemunblock)
			(*isaphysmemunblock)();
	}
}

/*
 * Handle a NMI, possibly a machine check.
 * return true to panic system, false to ignore.
 */
int
isa_nmi(cd) {

	log(LOG_CRIT, "\nNMI port 61 %x, port 70 %x\n", inb(0x61), inb(0x70));
	return(0);
}

/*
 * Caught a stray interrupt, notify
 */
void
isa_strayintr(d) {

	/* DON'T BOTHER FOR NOW! */
	/* for some reason, we get bursts of intr #7, even if not enabled! */
	/*
	 * Well the reason you got bursts of intr #7 is because someone
	 * raised an interrupt line and dropped it before the 8259 could
	 * prioritize it.  This is documented in the intel data book.  This
	 * means you have BAD hardware!  I have changed this so that only
	 * the first 5 get logged, then it quits logging them, and puts
	 * out a special message. rgrimes 3/25/1993
	 */
	extern u_long intrcnt_stray;

	intrcnt_stray++;
	if (intrcnt_stray <= 5)
		log(LOG_ERR,"ISA strayintr %x\n", d);
	if (intrcnt_stray == 5)
		log(LOG_CRIT,"Too many ISA strayintr not logging any more\n");
}

static beeping;
static void
sysbeepstop(int f)
{
	int s = splhigh();

	/* disable counter 2 */
	disable_intr();
	outb(PITAUX_PORT, inb(PITAUX_PORT) & ~PIT_SPKR);
	enable_intr();
	if (f)
		timeout((timeout_t)sysbeepstop, (caddr_t)0, f);
	else
		beeping = 0;

	splx(s);
}

void
sysbeep(int pitch, int period)
{
	int s = splhigh();
	static int last_pitch, last_period;

	if (beeping) {
		untimeout((timeout_t)sysbeepstop, (caddr_t)(last_period/2));
		untimeout((timeout_t)sysbeepstop, (caddr_t)0);
	}
	if (!beeping || last_pitch != pitch) {
		/*
	 	* XXX - move timer stuff to clock.c.
	 	*/
		disable_intr();
		outb(TIMER_MODE, TIMER_SEL2|TIMER_16BIT|TIMER_SQWAVE);
		outb(TIMER_CNTR2, TIMER_DIV(pitch)%256);
		outb(TIMER_CNTR2, TIMER_DIV(pitch)/256);
		outb(PITAUX_PORT, inb(PITAUX_PORT) | PIT_SPKR);	/* enable counter 2 */
		enable_intr();
	}
	last_pitch = pitch;
	beeping = last_period = period;
	timeout((timeout_t)sysbeepstop, (caddr_t)(period/2), period);

	splx(s);
}

/*
 * Return nonzero if a (masked) irq is pending for a given device.
 */
int
isa_irq_pending(dvp)
	struct isa_device *dvp;
{
	unsigned id_irq;

	id_irq = (unsigned short) dvp->id_irq;	/* XXX silly type in struct */
	if (id_irq & 0xff)
		return (inb(IO_ICU1) & id_irq);
	return (inb(IO_ICU2) & (id_irq >> 8));
}