freebsd-skq/sys/i386/isa/nmi.c

/*-
 * 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
 * $FreeBSD$
 */

#include "opt_auto_eoi.h"
#include "opt_isa.h"
#include "opt_mca.h"

#include <sys/param.h>
#include <sys/bus.h> 
#include <sys/errno.h>
#include <sys/interrupt.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/unistd.h>

#include <machine/md_var.h>
#include <machine/segments.h>

#if defined(APIC_IO)
#include <machine/smptests.h>			/** FAST_HI */
#include <machine/smp.h>
#include <machine/resource.h>
#endif /* APIC_IO */
#ifdef PC98
#include <pc98/pc98/pc98.h>
#include <pc98/pc98/pc98_machdep.h>
#include <pc98/pc98/epsonio.h>
#else
#include <i386/isa/isa.h>
#endif
#include <i386/isa/icu.h>

#ifdef DEV_ISA
#include <isa/isavar.h>
#endif
#include <i386/isa/intr_machdep.h>
#include <sys/interrupt.h>
#ifdef APIC_IO
#include <machine/clock.h>
#endif

#ifdef DEV_MCA
#include <i386/isa/mca_machdep.h>
#endif

/*
 * Per-interrupt data.
 */
u_long	*intr_countp[ICU_LEN];		/* pointers to interrupt counters */
driver_intr_t	*intr_handler[ICU_LEN];	/* first level interrupt handler */
struct	 ithd *ithds[ICU_LEN];		/* real interrupt handler */
void	*intr_unit[ICU_LEN];

static struct	mtx ithds_table_lock;	/* protect the ithds table */

static inthand_t *fastintr[ICU_LEN] = {
	&IDTVEC(fastintr0), &IDTVEC(fastintr1),
	&IDTVEC(fastintr2), &IDTVEC(fastintr3),
	&IDTVEC(fastintr4), &IDTVEC(fastintr5),
	&IDTVEC(fastintr6), &IDTVEC(fastintr7),
	&IDTVEC(fastintr8), &IDTVEC(fastintr9),
	&IDTVEC(fastintr10), &IDTVEC(fastintr11),
	&IDTVEC(fastintr12), &IDTVEC(fastintr13),
	&IDTVEC(fastintr14), &IDTVEC(fastintr15),
#if defined(APIC_IO)
	&IDTVEC(fastintr16), &IDTVEC(fastintr17),
	&IDTVEC(fastintr18), &IDTVEC(fastintr19),
	&IDTVEC(fastintr20), &IDTVEC(fastintr21),
	&IDTVEC(fastintr22), &IDTVEC(fastintr23),
	&IDTVEC(fastintr24), &IDTVEC(fastintr25),
	&IDTVEC(fastintr26), &IDTVEC(fastintr27),
	&IDTVEC(fastintr28), &IDTVEC(fastintr29),
	&IDTVEC(fastintr30), &IDTVEC(fastintr31),
#endif /* APIC_IO */
};

static unpendhand_t *fastunpend[ICU_LEN] = {
	&IDTVEC(fastunpend0), &IDTVEC(fastunpend1),
	&IDTVEC(fastunpend2), &IDTVEC(fastunpend3),
	&IDTVEC(fastunpend4), &IDTVEC(fastunpend5),
	&IDTVEC(fastunpend6), &IDTVEC(fastunpend7),
	&IDTVEC(fastunpend8), &IDTVEC(fastunpend9),
	&IDTVEC(fastunpend10), &IDTVEC(fastunpend11),
	&IDTVEC(fastunpend12), &IDTVEC(fastunpend13),
	&IDTVEC(fastunpend14), &IDTVEC(fastunpend15),
#if defined(APIC_IO)
	&IDTVEC(fastunpend16), &IDTVEC(fastunpend17),
	&IDTVEC(fastunpend18), &IDTVEC(fastunpend19),
	&IDTVEC(fastunpend20), &IDTVEC(fastunpend21),
	&IDTVEC(fastunpend22), &IDTVEC(fastunpend23),
	&IDTVEC(fastunpend24), &IDTVEC(fastunpend25),
	&IDTVEC(fastunpend26), &IDTVEC(fastunpend27),
	&IDTVEC(fastunpend28), &IDTVEC(fastunpend29),
	&IDTVEC(fastunpend30), &IDTVEC(fastunpend31),
#endif /* APIC_IO */
};

static inthand_t *slowintr[ICU_LEN] = {
	&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),
#if defined(APIC_IO)
	&IDTVEC(intr16), &IDTVEC(intr17), &IDTVEC(intr18), &IDTVEC(intr19),
	&IDTVEC(intr20), &IDTVEC(intr21), &IDTVEC(intr22), &IDTVEC(intr23),
	&IDTVEC(intr24), &IDTVEC(intr25), &IDTVEC(intr26), &IDTVEC(intr27),
	&IDTVEC(intr28), &IDTVEC(intr29), &IDTVEC(intr30), &IDTVEC(intr31),
#endif /* APIC_IO */
};

static driver_intr_t isa_strayintr;

static void	ithds_init(void *dummy);
static void	ithread_enable(int vector);
static void	ithread_disable(int vector);
static void	init_i8259(void);

#ifdef PC98
#define NMI_PARITY 0x04
#define NMI_EPARITY 0x02
#else
#define NMI_PARITY (1 << 7)
#define NMI_IOCHAN (1 << 6)
#define ENMI_WATCHDOG (1 << 7)
#define ENMI_BUSTIMER (1 << 6)
#define ENMI_IOSTATUS (1 << 5)
#endif

#ifdef DEV_ISA
/*
 * Bus attachment for the ISA PIC.
 */
static struct isa_pnp_id atpic_ids[] = {
	{ 0x0000d041 /* PNP0000 */, "AT interrupt controller" },
	{ 0 }
};

static int
atpic_probe(device_t dev)
{
	int result;
	
	if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, atpic_ids)) <= 0)
		device_quiet(dev);
	return(result);
}

/*
 * In the APIC_IO case we might be granted IRQ 2, as this is typically
 * consumed by chaining between the two PIC components.  If we're using
 * the APIC, however, this may not be the case, and as such we should
 * free the resource.  (XXX untested)
 *
 * The generic ISA attachment code will handle allocating any other resources
 * that we don't explicitly claim here.
 */
static int
atpic_attach(device_t dev)
{
#ifdef APIC_IO
	int		rid;
	struct resource *res;

	/* try to allocate our IRQ and then free it */
	rid = 0;
	res = bus_alloc_resource(dev, SYS_RES_IRQ, &rid, 0, ~0, 1, 0);
	if (res != NULL)
		bus_release_resource(dev, SYS_RES_IRQ, rid, res);
#endif
	return(0);
}

static device_method_t atpic_methods[] = {
	/* Device interface */
	DEVMETHOD(device_probe,		atpic_probe),
	DEVMETHOD(device_attach,	atpic_attach),
	DEVMETHOD(device_detach,	bus_generic_detach),
	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
	DEVMETHOD(device_suspend,	bus_generic_suspend),
	DEVMETHOD(device_resume,	bus_generic_resume),
	{ 0, 0 }
};

static driver_t atpic_driver = {
	"atpic",
	atpic_methods,
	1,		/* no softc */
};

static devclass_t atpic_devclass;

DRIVER_MODULE(atpic, isa, atpic_driver, atpic_devclass, 0, 0);
DRIVER_MODULE(atpic, acpi, atpic_driver, atpic_devclass, 0, 0);
#endif /* DEV_ISA */

/*
 * Handle a NMI, possibly a machine check.
 * return true to panic system, false to ignore.
 */
int
isa_nmi(cd)
	int cd;
{
	int retval = 0;
#ifdef PC98
 	int port = inb(0x33);

	log(LOG_CRIT, "NMI PC98 port = %x\n", port);
	if (epson_machine_id == 0x20)
		epson_outb(0xc16, epson_inb(0xc16) | 0x1);
	if (port & NMI_PARITY) {
		log(LOG_CRIT, "BASE RAM parity error, likely hardware failure.");
		retval = 1;
	} else if (port & NMI_EPARITY) {
		log(LOG_CRIT, "EXTENDED RAM parity error, likely hardware failure.");
		retval = 1;
	} else {
		log(LOG_CRIT, "\nNMI Resume ??\n");
	}
#else /* IBM-PC */
	int isa_port = inb(0x61);
	int eisa_port = inb(0x461);

	log(LOG_CRIT, "NMI ISA %x, EISA %x\n", isa_port, eisa_port);
#ifdef DEV_MCA
	if (MCA_system && mca_bus_nmi())
		return(0);
#endif
	
	if (isa_port & NMI_PARITY) {
		log(LOG_CRIT, "RAM parity error, likely hardware failure.");
		retval = 1;
	}

	if (isa_port & NMI_IOCHAN) {
		log(LOG_CRIT, "I/O channel check, likely hardware failure.");
		retval = 1;
	}

	/*
	 * On a real EISA machine, this will never happen.  However it can
	 * happen on ISA machines which implement XT style floating point
	 * error handling (very rare).  Save them from a meaningless panic.
	 */
	if (eisa_port == 0xff)
		return(retval);

	if (eisa_port & ENMI_WATCHDOG) {
		log(LOG_CRIT, "EISA watchdog timer expired, likely hardware failure.");
		retval = 1;
	}

	if (eisa_port & ENMI_BUSTIMER) {
		log(LOG_CRIT, "EISA bus timeout, likely hardware failure.");
		retval = 1;
	}

	if (eisa_port & ENMI_IOSTATUS) {
		log(LOG_CRIT, "EISA I/O port status error.");
		retval = 1;
	}
#endif
	return(retval);
}

/*
 *  ICU reinitialize when ICU configuration has lost.
 */
void icu_reinit()
{
	int i;
	register_t crit;

	crit = intr_disable();
	mtx_lock_spin(&icu_lock);
	init_i8259();
	for(i=0;i<ICU_LEN;i++)
		if(intr_handler[i] != isa_strayintr)
			INTREN(1<<i);
	mtx_unlock_spin(&icu_lock);
	intr_restore(crit);
}

/*
 * Create a default interrupt table to avoid problems caused by
 * spurious interrupts during configuration of kernel, then setup
 * interrupt control unit.
 */
void
isa_defaultirq()
{
	int i;
	register_t crit;

	/* icu vectors */
	for (i = 0; i < ICU_LEN; i++)
		icu_unset(i, (driver_intr_t *)NULL);
	crit = intr_disable();
	mtx_lock_spin(&icu_lock);
	init_i8259();
	mtx_unlock_spin(&icu_lock);
	intr_restore(crit);
}


/* 
 *initialize 8259's
 */
static void init_i8259()
{

#ifdef DEV_MCA
	if (MCA_system)
		outb(IO_ICU1, 0x19);		/* reset; program device, four bytes */
	else
#endif
		outb(IO_ICU1, 0x11);		/* reset; program device, four bytes */

	outb(IO_ICU1+ICU_IMR_OFFSET, NRSVIDT);	/* starting at this vector index */
	outb(IO_ICU1+ICU_IMR_OFFSET, IRQ_SLAVE);		/* slave on line 7 */
#ifdef PC98
#ifdef AUTO_EOI_1
	outb(IO_ICU1+ICU_IMR_OFFSET, 0x1f);		/* (master) auto EOI, 8086 mode */
#else
	outb(IO_ICU1+ICU_IMR_OFFSET, 0x1d);		/* (master) 8086 mode */
#endif
#else /* IBM-PC */
#ifdef AUTO_EOI_1
	outb(IO_ICU1+ICU_IMR_OFFSET, 2 | 1);		/* auto EOI, 8086 mode */
#else
	outb(IO_ICU1+ICU_IMR_OFFSET, 1);		/* 8086 mode */
#endif
#endif /* PC98 */
	outb(IO_ICU1+ICU_IMR_OFFSET, 0xff);		/* leave interrupts masked */
	outb(IO_ICU1, 0x0a);		/* default to IRR on read */
#ifndef PC98
	outb(IO_ICU1, 0xc0 | (3 - 1));	/* pri order 3-7, 0-2 (com2 first) */
#endif /* !PC98 */

#ifdef DEV_MCA
	if (MCA_system)
		outb(IO_ICU2, 0x19);		/* reset; program device, four bytes */
	else
#endif
		outb(IO_ICU2, 0x11);		/* reset; program device, four bytes */

	outb(IO_ICU2+ICU_IMR_OFFSET, NRSVIDT+8); /* staring at this vector index */
	outb(IO_ICU2+ICU_IMR_OFFSET, ICU_SLAVEID);         /* my slave id is 7 */
#ifdef PC98
	outb(IO_ICU2+ICU_IMR_OFFSET,9);              /* 8086 mode */
#else /* IBM-PC */
#ifdef AUTO_EOI_2
	outb(IO_ICU2+ICU_IMR_OFFSET, 2 | 1);		/* auto EOI, 8086 mode */
#else
	outb(IO_ICU2+ICU_IMR_OFFSET,1);		/* 8086 mode */
#endif
#endif /* PC98 */
	outb(IO_ICU2+ICU_IMR_OFFSET, 0xff);          /* leave interrupts masked */
	outb(IO_ICU2, 0x0a);		/* default to IRR on read */
}

/*
 * Caught a stray interrupt, notify
 */
static void
isa_strayintr(vcookiep)
	void *vcookiep;
{
	int intr = (void **)vcookiep - &intr_unit[0];

	/*
	 * XXX TODO print a different message for #7 if it is for a
	 * glitch.  Glitches can be distinguished from real #7's by
	 * testing that the in-service bit is _not_ set.  The test
	 * must be done before sending an EOI so it can't be done if
	 * we are using AUTO_EOI_1.
	 */
	if (intrcnt[1 + intr] <= 5)
		log(LOG_ERR, "stray irq %d\n", intr);
	if (intrcnt[1 + intr] == 5)
		log(LOG_CRIT,
		    "too many stray irq %d's; not logging any more\n", intr);
}

#ifdef DEV_ISA
/*
 * Return a bitmap of the current interrupt requests.  This is 8259-specific
 * and is only suitable for use at probe time.
 */
intrmask_t
isa_irq_pending()
{
	u_char irr1;
	u_char irr2;

	irr1 = inb(IO_ICU1);
	irr2 = inb(IO_ICU2);
	return ((irr2 << 8) | irr1);
}
#endif

/*
 * Update intrnames array with the specified name.  This is used by
 * vmstat(8) and the like.
 */
static void
update_intrname(int intr, const char *name)
{
	char buf[32];
	char *cp;
	int name_index, off, strayintr;

	/*
	 * Initialise strings for bitbucket and stray interrupt counters.
	 * These have statically allocated indices 0 and 1 through ICU_LEN.
	 */
	if (intrnames[0] == '\0') {
		off = sprintf(intrnames, "???") + 1;
		for (strayintr = 0; strayintr < ICU_LEN; strayintr++)
			off += sprintf(intrnames + off, "stray irq%d",
			    strayintr) + 1;
	}

	if (name == NULL)
		name = "???";
	if (snprintf(buf, sizeof(buf), "%s irq%d", name, intr) >= sizeof(buf))
		goto use_bitbucket;

	/*
	 * Search for `buf' in `intrnames'.  In the usual case when it is
	 * not found, append it to the end if there is enough space (the \0
	 * terminator for the previous string, if any, becomes a separator).
	 */
	for (cp = intrnames, name_index = 0;
	    cp != eintrnames && name_index < NR_INTRNAMES;
	    cp += strlen(cp) + 1, name_index++) {
		if (*cp == '\0') {
			if (strlen(buf) >= eintrnames - cp)
				break;
			strcpy(cp, buf);
			goto found;
		}
		if (strcmp(cp, buf) == 0)
			goto found;
	}

use_bitbucket:
	printf("update_intrname: counting %s irq%d as %s\n", name, intr,
	    intrnames);
	name_index = 0;
found:
	intr_countp[intr] = &intrcnt[name_index];
}

int
icu_setup(int intr, driver_intr_t *handler, void *arg, int flags)
{
#ifdef FAST_HI
	int		select;		/* the select register is 8 bits */
	int		vector;
	u_int32_t	value;		/* the window register is 32 bits */
#endif /* FAST_HI */
	register_t	crit;

#if defined(APIC_IO)
	if ((u_int)intr >= ICU_LEN)	/* no 8259 SLAVE to ignore */
#else
	if ((u_int)intr >= ICU_LEN || intr == ICU_SLAVEID)
#endif /* APIC_IO */
		return (EINVAL);
#if 0
	if (intr_handler[intr] != isa_strayintr)
		return (EBUSY);
#endif

	crit = intr_disable();
	mtx_lock_spin(&icu_lock);
	intr_handler[intr] = handler;
	intr_unit[intr] = arg;
#ifdef FAST_HI
	if (flags & INTR_FAST) {
		vector = TPR_FAST_INTS + intr;
		setidt(vector, fastintr[intr],
		       SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
	}
	else {
		vector = TPR_SLOW_INTS + intr;
#ifdef APIC_INTR_REORDER
#ifdef APIC_INTR_HIGHPRI_CLOCK
		/* XXX: Hack (kludge?) for more accurate clock. */
		if (intr == apic_8254_intr || intr == 8) {
			vector = TPR_FAST_INTS + intr;
		}
#endif
#endif
		setidt(vector, slowintr[intr],
		       SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
	}
#ifdef APIC_INTR_REORDER
	set_lapic_isrloc(intr, vector);
#endif
	/*
	 * Reprogram the vector in the IO APIC.
	 */
	if (int_to_apicintpin[intr].ioapic >= 0) {
		select = int_to_apicintpin[intr].redirindex;
		value = io_apic_read(int_to_apicintpin[intr].ioapic, 
				     select) & ~IOART_INTVEC;
		io_apic_write(int_to_apicintpin[intr].ioapic, 
			      select, value | vector);
	}
#else
	setidt(ICU_OFFSET + intr,
	       flags & INTR_FAST ? fastintr[intr] : slowintr[intr],
	       SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
#endif /* FAST_HI */
	INTREN(1 << intr);
	mtx_unlock_spin(&icu_lock);
	intr_restore(crit);
	return (0);
}

/*
 * Dissociate an interrupt handler from an IRQ and set the handler to
 * the stray interrupt handler.  The 'handler' parameter is used only
 * for consistency checking.
 */
int
icu_unset(intr, handler)
	int	intr;
	driver_intr_t *handler;
{
	register_t crit;

	if ((u_int)intr >= ICU_LEN || handler != intr_handler[intr])
		return (EINVAL);

	crit = intr_disable();
	mtx_lock_spin(&icu_lock);
	INTRDIS(1 << intr);
	intr_countp[intr] = &intrcnt[1 + intr];
	intr_handler[intr] = isa_strayintr;
	intr_unit[intr] = &intr_unit[intr];
#ifdef FAST_HI_XXX
	/* XXX how do I re-create dvp here? */
	setidt(flags & INTR_FAST ? TPR_FAST_INTS + intr : TPR_SLOW_INTS + intr,
	    slowintr[intr], SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
#else /* FAST_HI */
#ifdef APIC_INTR_REORDER
	set_lapic_isrloc(intr, ICU_OFFSET + intr);
#endif
	setidt(ICU_OFFSET + intr, slowintr[intr], SDT_SYS386IGT, SEL_KPL,
	    GSEL(GCODE_SEL, SEL_KPL));
#endif /* FAST_HI */
	mtx_unlock_spin(&icu_lock);
	intr_restore(crit);
	return (0);
}

static void
ithds_init(void *dummy)
{

	mtx_init(&ithds_table_lock, "ithread table lock", MTX_SPIN);
}
SYSINIT(ithds_init, SI_SUB_INTR, SI_ORDER_SECOND, ithds_init, NULL);

static void
ithread_enable(int vector)
{
	register_t crit;

	crit = intr_disable();
	mtx_lock_spin(&icu_lock);
	INTREN(1 << vector);
	mtx_unlock_spin(&icu_lock);
	intr_restore(crit);
}

static void
ithread_disable(int vector)
{
	register_t crit;

	crit = intr_disable();
	mtx_lock_spin(&icu_lock);
	INTRDIS(1 << vector);
	mtx_unlock_spin(&icu_lock);
	intr_restore(crit);
}

int
inthand_add(const char *name, int irq, driver_intr_t handler, void *arg,
    enum intr_type flags, void **cookiep)
{
	struct ithd *ithd;		/* descriptor for the IRQ */
	int errcode = 0;
	int created_ithd = 0;

	/*
	 * Work around a race where more than one CPU may be registering
	 * handlers on the same IRQ at the same time.
	 */
	mtx_lock_spin(&ithds_table_lock);
	ithd = ithds[irq];
	mtx_unlock_spin(&ithds_table_lock);
	if (ithd == NULL) {
		errcode = ithread_create(&ithd, irq, 0, ithread_disable,
		    ithread_enable, "irq%d:", irq);
		if (errcode)
			return (errcode);
		mtx_lock_spin(&ithds_table_lock);
		if (ithds[irq] == NULL) {
			ithds[irq] = ithd;
			created_ithd++;
			mtx_unlock_spin(&ithds_table_lock);
		} else {
			struct ithd *orphan;

			orphan = ithd;
			ithd = ithds[irq];
			mtx_unlock_spin(&ithds_table_lock);
			ithread_destroy(orphan);
		}
	}

	errcode = ithread_add_handler(ithd, name, handler, arg,
	    ithread_priority(flags), flags, cookiep);
	
	if ((flags & INTR_FAST) == 0 || errcode)
		/*
		 * The interrupt process must be in place, but
		 * not necessarily schedulable, before we
		 * initialize the ICU, since it may cause an
		 * immediate interrupt.
		 */
		if (icu_setup(irq, &sched_ithd, arg, flags) != 0)
			panic("inthand_add: Can't initialize ICU");

	if (errcode)
		return (errcode);
	
	if (flags & INTR_FAST) {
		errcode = icu_setup(irq, handler, arg, flags);
		if (errcode && bootverbose)
			printf("\tinthand_add(irq%d) failed, result=%d\n", 
			       irq, errcode);
		if (errcode)
			return (errcode);
	}

	update_intrname(irq, name);
	return (0);
}

/*
 * Deactivate and remove linked list the interrupt handler descriptor
 * data connected created by an earlier call of inthand_add(), then
 * adjust the interrupt masks if necessary.
 *
 * Return the memory held by the interrupt handler descriptor data
 * structure to the system.  First ensure the handler is not actively
 * in use.
 */
int
inthand_remove(void *cookie)
{

	return (ithread_remove_handler(cookie));
}

void
call_fast_unpend(int irq)
{
 	fastunpend[irq]();
}