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isabus.c revision 1.53
      1 /*	$NetBSD: isabus.c,v 1.53 2021/08/07 16:18:42 thorpej Exp $	*/
      2 /*	$OpenBSD: isabus.c,v 1.15 1998/03/16 09:38:46 pefo Exp $	*/
      3 /*	NetBSD: isa.c,v 1.33 1995/06/28 04:30:51 cgd Exp 	*/
      4 
      5 /*-
      6  * Copyright (c) 1990 The Regents of the University of California.
      7  * All rights reserved.
      8  *
      9  * This code is derived from software contributed to Berkeley by
     10  * William Jolitz and Don Ahn.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. Neither the name of the University nor the names of its contributors
     21  *    may be used to endorse or promote products derived from this software
     22  *    without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  *
     36  *	@(#)isa.c	7.2 (Berkeley) 5/12/91
     37  */
     38 /*-
     39  * Copyright (c) 1995 Per Fogelstrom
     40  * Copyright (c) 1993, 1994 Charles M. Hannum.
     41  *
     42  * This code is derived from software contributed to Berkeley by
     43  * William Jolitz and Don Ahn.
     44  *
     45  * Redistribution and use in source and binary forms, with or without
     46  * modification, are permitted provided that the following conditions
     47  * are met:
     48  * 1. Redistributions of source code must retain the above copyright
     49  *    notice, this list of conditions and the following disclaimer.
     50  * 2. Redistributions in binary form must reproduce the above copyright
     51  *    notice, this list of conditions and the following disclaimer in the
     52  *    documentation and/or other materials provided with the distribution.
     53  * 3. All advertising materials mentioning features or use of this software
     54  *    must display the following acknowledgement:
     55  *	This product includes software developed by the University of
     56  *	California, Berkeley and its contributors.
     57  * 4. Neither the name of the University nor the names of its contributors
     58  *    may be used to endorse or promote products derived from this software
     59  *    without specific prior written permission.
     60  *
     61  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     62  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     63  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     64  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     65  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     66  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     67  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     68  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     69  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     70  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     71  * SUCH DAMAGE.
     72  *
     73  *	@(#)isa.c	7.2 (Berkeley) 5/12/91
     74  */
     75 /*
     76  * Mach Operating System
     77  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
     78  * All Rights Reserved.
     79  *
     80  * Permission to use, copy, modify and distribute this software and its
     81  * documentation is hereby granted, provided that both the copyright
     82  * notice and this permission notice appear in all copies of the
     83  * software, derivative works or modified versions, and any portions
     84  * thereof, and that both notices appear in supporting documentation.
     85  *
     86  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     87  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     88  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     89  *
     90  * Carnegie Mellon requests users of this software to return to
     91  *
     92  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     93  *  School of Computer Science
     94  *  Carnegie Mellon University
     95  *  Pittsburgh PA 15213-3890
     96  *
     97  * any improvements or extensions that they make and grant Carnegie Mellon
     98  * the rights to redistribute these changes.
     99  */
    100 /*
    101   Copyright 1988, 1989 by Intel Corporation, Santa Clara, California.
    102 
    103 		All Rights Reserved
    104 
    105 Permission to use, copy, modify, and distribute this software and
    106 its documentation for any purpose and without fee is hereby
    107 granted, provided that the above copyright notice appears in all
    108 copies and that both the copyright notice and this permission notice
    109 appear in supporting documentation, and that the name of Intel
    110 not be used in advertising or publicity pertaining to distribution
    111 of the software without specific, written prior permission.
    112 
    113 INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
    114 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
    115 IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
    116 CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
    117 LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
    118 NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
    119 WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
    120 */
    121 
    122 #include <sys/cdefs.h>
    123 __KERNEL_RCSID(0, "$NetBSD: isabus.c,v 1.53 2021/08/07 16:18:42 thorpej Exp $");
    124 
    125 #include <sys/param.h>
    126 #include <sys/proc.h>
    127 #include <sys/systm.h>
    128 #include <sys/callout.h>
    129 #include <sys/time.h>
    130 #include <sys/kernel.h>
    131 #include <sys/device.h>
    132 #include <sys/kmem.h>
    133 #include <sys/extent.h>
    134 
    135 #include <uvm/uvm_extern.h>
    136 
    137 #include <machine/cpu.h>
    138 #include <machine/pio.h>
    139 #include <machine/autoconf.h>
    140 #include <machine/intr.h>
    141 
    142 #include <mips/locore.h>
    143 
    144 #include <dev/ic/i8253reg.h>
    145 #include <dev/ic/i8259reg.h>
    146 #include <dev/isa/isareg.h>
    147 #include <dev/isa/isavar.h>
    148 #include <arc/isa/isabrvar.h>
    149 #include <arc/isa/spkrreg.h>
    150 
    151 #include <arc/arc/timervar.h>
    152 
    153 static int beeping;
    154 static callout_t sysbeep_ch;
    155 
    156 static long isa_mem_ex_storage[EXTENT_FIXED_STORAGE_SIZE(16) / sizeof(long)];
    157 static long isa_io_ex_storage[EXTENT_FIXED_STORAGE_SIZE(16) / sizeof(long)];
    158 
    159 #define	IRQ_SLAVE	2
    160 
    161 /* Definition of the driver for autoconfig. */
    162 static int isabrprint(void *, const char *);
    163 
    164 extern struct arc_bus_space arc_bus_io, arc_bus_mem;
    165 
    166 static void isabr_attach_hook(device_t , device_t,
    167     struct isabus_attach_args *);
    168 static void isabr_detach_hook(isa_chipset_tag_t, device_t);
    169 static const struct evcnt *isabr_intr_evcnt(isa_chipset_tag_t, int);
    170 static void *isabr_intr_establish(isa_chipset_tag_t, int, int, int,
    171     int (*)(void *), void *);
    172 static void isabr_intr_disestablish(isa_chipset_tag_t, void*);
    173 static void isabr_initicu(void);
    174 static void intr_calculatemasks(void);
    175 static int fakeintr(void *a);
    176 
    177 struct isabr_config *isabr_conf = NULL;
    178 uint32_t imask[_IPL_N];	/* XXX */
    179 
    180 void
    181 isabrattach(struct isabr_softc *sc)
    182 {
    183 	struct isabus_attach_args iba;
    184 
    185 	callout_init(&sysbeep_ch, 0);
    186 
    187 	if (isabr_conf == NULL)
    188 		panic("isabr_conf isn't initialized");
    189 
    190 	aprint_normal("\n");
    191 
    192 	/* Initialize interrupt controller */
    193 	isabr_initicu();
    194 
    195 	sc->arc_isa_cs.ic_attach_hook = isabr_attach_hook;
    196 	sc->arc_isa_cs.ic_detach_hook = isabr_detach_hook;
    197 	sc->arc_isa_cs.ic_intr_evcnt = isabr_intr_evcnt;
    198 	sc->arc_isa_cs.ic_intr_establish = isabr_intr_establish;
    199 	sc->arc_isa_cs.ic_intr_disestablish = isabr_intr_disestablish;
    200 
    201 	arc_bus_space_init_extent(&arc_bus_mem, (void *)isa_mem_ex_storage,
    202 	    sizeof(isa_mem_ex_storage));
    203 	arc_bus_space_init_extent(&arc_bus_io, (void *)isa_io_ex_storage,
    204 	    sizeof(isa_io_ex_storage));
    205 
    206 	iba.iba_iot = &arc_bus_io;
    207 	iba.iba_memt = &arc_bus_mem;
    208 	iba.iba_dmat = &sc->sc_dmat;
    209 	iba.iba_ic = &sc->arc_isa_cs;
    210 	config_found(sc->sc_dev, &iba, isabrprint,
    211 	    CFARGS(.iattr = "isabus"));
    212 }
    213 
    214 static int
    215 isabrprint(void *aux, const char *pnp)
    216 {
    217 
    218         if (pnp)
    219                 aprint_normal("isa at %s", pnp);
    220         aprint_verbose(" isa_io_base 0x%"PRIxVADDR" isa_mem_base 0x%"PRIxVADDR,
    221 	    arc_bus_io.bs_vbase, arc_bus_mem.bs_vbase);
    222         return UNCONF;
    223 }
    224 
    225 
    226 /*
    227  *	Interrupt system driver code
    228  *	============================
    229  */
    230 #define LEGAL_IRQ(x)    ((x) >= 0 && (x) < ICU_LEN && (x) != 2)
    231 
    232 int	imen;
    233 int	intrtype[ICU_LEN], intrmask[ICU_LEN], intrlevel[ICU_LEN];
    234 struct isa_intrhand *isa_intrhand[ICU_LEN];
    235 
    236 static int
    237 fakeintr(void *a)
    238 {
    239 
    240 	return 0;
    241 }
    242 
    243 /*
    244  * Recalculate the interrupt masks from scratch.
    245  * We could code special registry and deregistry versions of this function that
    246  * would be faster, but the code would be nastier, and we don't expect this to
    247  * happen very much anyway.
    248  */
    249 static void
    250 intr_calculatemasks(void)
    251 {
    252 	int irq, level;
    253 	struct isa_intrhand *q;
    254 
    255 	/* First, figure out which levels each IRQ uses. */
    256 	for (irq = 0; irq < ICU_LEN; irq++) {
    257 		int levels = 0;
    258 		for (q = isa_intrhand[irq]; q; q = q->ih_next)
    259 			levels |= 1 << q->ih_level;
    260 		intrlevel[irq] = levels;
    261 	}
    262 
    263 	/* Then figure out which IRQs use each level. */
    264 	for (level = 0; level < _IPL_N; level++) {
    265 		int irqs = 0;
    266 		for (irq = 0; irq < ICU_LEN; irq++)
    267 			if (intrlevel[irq] & (1 << level))
    268 				irqs |= 1 << irq;
    269 		imask[level] = irqs;
    270 	}
    271 
    272 	imask[IPL_NONE] = 0;
    273 
    274 	imask[IPL_SOFTCLOCK] |= imask[IPL_NONE];
    275 	imask[IPL_SOFTNET] |= imask[IPL_SOFTCLOCK];
    276 
    277 	/*
    278 	 * Enforce a hierarchy that gives slow devices a better chance at not
    279 	 * dropping data.
    280 	 */
    281 	imask[IPL_VM] |= imask[IPL_SOFTNET];
    282 
    283 	/*
    284 	 * Since run queues may be manipulated by both the statclock and tty,
    285 	 * network, and diskdrivers, clock > tty.
    286 	 */
    287 	imask[IPL_SCHED] |= imask[IPL_VM];
    288 
    289 	/* And eventually calculate the complete masks. */
    290 	for (irq = 0; irq < ICU_LEN; irq++) {
    291 		int irqs = 1 << irq;
    292 		for (q = isa_intrhand[irq]; q; q = q->ih_next)
    293 			irqs |= imask[q->ih_level];
    294 		intrmask[irq] = irqs;
    295 	}
    296 
    297 	/* Lastly, determine which IRQs are actually in use. */
    298 	{
    299 		int irqs = 0;
    300 		for (irq = 0; irq < ICU_LEN; irq++)
    301 			if (isa_intrhand[irq])
    302 				irqs |= 1 << irq;
    303 		if (irqs >= 0x100) /* any IRQs >= 8 in use */
    304 			irqs |= 1 << IRQ_SLAVE;
    305 		imen = ~irqs;
    306 		isa_outb(IO_ICU1 + PIC_OCW1, imen);
    307 		isa_outb(IO_ICU2 + PIC_OCW1, imen >> 8);
    308 	}
    309 }
    310 
    311 static void
    312 isabr_attach_hook(device_t parent, device_t self,
    313     struct isabus_attach_args *iba)
    314 {
    315 
    316 	/* Nothing to do. */
    317 }
    318 
    319 static void
    320 isabr_detach_hook(isa_chipset_tag_t ic, device_t self)
    321 {
    322 
    323 	/* Nothing to do. */
    324 }
    325 
    326 static const struct evcnt *
    327 isabr_intr_evcnt(isa_chipset_tag_t ic, int irq)
    328 {
    329 
    330 	/* XXX for now, no evcnt parent reported */
    331 	return NULL;
    332 }
    333 
    334 /*
    335  *	Establish a ISA bus interrupt.
    336  */
    337 static void *
    338 isabr_intr_establish(isa_chipset_tag_t ic, int irq, int type, int level,
    339     int (*ih_fun)(void *), void *ih_arg)
    340 {
    341 	struct isa_intrhand **p, *q, *ih;
    342 	static struct isa_intrhand fakehand = {NULL, fakeintr};
    343 
    344 	ih = kmem_alloc(sizeof *ih, KM_SLEEP);
    345 
    346 	if (!LEGAL_IRQ(irq) || type == IST_NONE)
    347 		panic("intr_establish: bogus irq or type");
    348 
    349 	switch (intrtype[irq]) {
    350 	case IST_NONE:
    351 		intrtype[irq] = type;
    352 		break;
    353 	case IST_EDGE:
    354 	case IST_LEVEL:
    355 		if (type == intrtype[irq])
    356 			break;
    357 	case IST_PULSE:
    358 		if (type != IST_NONE)
    359 			panic("intr_establish: can't share %s with %s",
    360 			    isa_intr_typename(intrtype[irq]),
    361 			    isa_intr_typename(type));
    362 		break;
    363 	}
    364 
    365 	/*
    366 	 * Figure out where to put the handler.
    367 	 * This is O(N^2), but we want to preserve the order, and N is
    368 	 * generally small.
    369 	 */
    370 	for (p = &isa_intrhand[irq]; (q = *p) != NULL; p = &q->ih_next)
    371 		;
    372 
    373 	/*
    374 	 * Actually install a fake handler momentarily, since we might be doing
    375 	 * this with interrupts enabled and don't want the real routine called
    376 	 * until masking is set up.
    377 	 */
    378 	fakehand.ih_level = level;
    379 	*p = &fakehand;
    380 
    381 	intr_calculatemasks();
    382 
    383 	/*
    384 	 * Poke the real handler in now.
    385 	 */
    386 	ih->ih_fun = ih_fun;
    387 	ih->ih_arg = ih_arg;
    388 	ih->ih_count = 0;
    389 	ih->ih_next = NULL;
    390 	ih->ih_level = level;
    391 	ih->ih_irq = irq;
    392 	snprintf(ih->ih_evname, sizeof(ih->ih_evname), "irq %d", irq);
    393 	evcnt_attach_dynamic(&ih->ih_evcnt, EVCNT_TYPE_INTR, NULL, "isa",
    394 	    ih->ih_evname);
    395 	*p = ih;
    396 
    397 	return ih;
    398 }
    399 
    400 static void
    401 isabr_intr_disestablish(isa_chipset_tag_t ic, void *arg)
    402 {
    403 
    404 }
    405 
    406 /*
    407  *	Process an interrupt from the ISA bus.
    408  */
    409 uint32_t
    410 isabr_iointr(uint32_t mask, struct clockframe *cf)
    411 {
    412 	struct isa_intrhand *ih;
    413 	int isa_vector;
    414 	int o_imen;
    415 
    416 	isa_vector = (*isabr_conf->ic_intr_status)();
    417 	if (isa_vector < 0)
    418 		return 0;
    419 
    420 	o_imen = imen;
    421 	imen |= 1 << (isa_vector & (ICU_LEN - 1));
    422 	if (isa_vector & 0x08) {
    423 		isa_inb(IO_ICU2 + PIC_OCW1);
    424 		isa_outb(IO_ICU2 + PIC_OCW1, imen >> 8);
    425 		isa_outb(IO_ICU2 + PIC_OCW2,
    426 		    OCW2_SELECT | OCW2_EOI | OCW2_SL |
    427 		    OCW2_ILS((isa_vector & 7)));
    428 		isa_outb(IO_ICU1,
    429 		    OCW2_SELECT | OCW2_EOI | OCW2_SL | IRQ_SLAVE);
    430 	} else {
    431 		isa_inb(IO_ICU1 + PIC_OCW1);
    432 		isa_outb(IO_ICU1 + PIC_OCW1, imen);
    433 		isa_outb(IO_ICU1 + PIC_OCW2,
    434 		    OCW2_SELECT | OCW2_EOI | OCW2_SL | OCW2_ILS(isa_vector));
    435 	}
    436 	ih = isa_intrhand[isa_vector];
    437 	if (isa_vector == 0 && ih) {	/* Clock */	/*XXX*/
    438 		last_cp0_count = mips3_cp0_count_read();
    439 		/* XXX: spllowerclock() not allowed */
    440 		cf->sr &= ~MIPS_SR_INT_IE;
    441 		if ((*ih->ih_fun)(cf))
    442 			ih->ih_evcnt.ev_count++;
    443 		ih = ih->ih_next;
    444 	}
    445 	while (ih) {
    446 		if ((*ih->ih_fun)(ih->ih_arg))
    447 			ih->ih_evcnt.ev_count++;
    448 		ih = ih->ih_next;
    449 	}
    450 	imen = o_imen;
    451 	isa_inb(IO_ICU1 + PIC_OCW1);
    452 	isa_inb(IO_ICU2 + PIC_OCW1);
    453 	isa_outb(IO_ICU1 + PIC_OCW1, imen);
    454 	isa_outb(IO_ICU2 + PIC_OCW1, imen >> 8);
    455 
    456 	return MIPS_INT_MASK_2;
    457 }
    458 
    459 
    460 /*
    461  * Initialize the Interrupt controller logic.
    462  */
    463 static void
    464 isabr_initicu(void)
    465 {
    466 
    467 	int i;
    468 
    469 	for (i = 0; i < ICU_LEN; i++) {
    470 		switch (i) {
    471 		case 2:
    472 		case 8:
    473 			intrtype[i] = IST_EDGE;
    474 			break;
    475 		default:
    476 			intrtype[i] = IST_NONE;
    477 			break;
    478 		}
    479 	}
    480 
    481 	/* reset; program device, four bytes */
    482 	isa_outb(IO_ICU1 + PIC_ICW1, ICW1_SELECT | ICW1_IC4);
    483 	/* starting at this vector index */
    484 	isa_outb(IO_ICU1 + PIC_ICW2, 0);
    485 	/* slave on line 2 */
    486 	isa_outb(IO_ICU1 + PIC_ICW3, ICW3_CASCADE(IRQ_SLAVE));
    487 	/* 8086 mode */
    488 	isa_outb(IO_ICU1 + PIC_ICW4, ICW4_8086);
    489 
    490 	/* leave interrupts masked */
    491 	isa_outb(IO_ICU1 + PIC_OCW1, 0xff);
    492 
    493 	/* special mask mode (if available) */
    494 	isa_outb(IO_ICU1 + PIC_OCW3, OCW3_SELECT | OCW3_SSMM | OCW3_SMM);
    495 	/* Read IRR by default. */
    496 	isa_outb(IO_ICU1 + PIC_OCW3, OCW3_SELECT | OCW3_RR);
    497 #ifdef REORDER_IRQ
    498 	/* pri order 3-7, 0-2 (com2 first) */
    499 	isa_outb(IO_ICU1 + PIC_OCW2,
    500 	    OCW2_SELECT | OCW2_R | OCW2_SL OCW2_ILS(3 - 1));
    501 #endif
    502 
    503 	/* reset; program device, four bytes */
    504 	isa_outb(IO_ICU2 + PIC_ICW1, ICW1_SELECT | ICW1_IC4);
    505 	/* staring at this vector index */
    506 	isa_outb(IO_ICU2 + PIC_ICW2, 8);
    507 	/* slave connected to line 2 of master */
    508 	isa_outb(IO_ICU2 + PIC_ICW3, ICW3_SIC(IRQ_SLAVE));
    509 	/* 8086 mode */
    510 	isa_outb(IO_ICU2 + PIC_ICW4, ICW4_8086);
    511 
    512 	/* leave interrupts masked */
    513 	isa_outb(IO_ICU2 + PIC_OCW1, 0xff);
    514 
    515 	/* special mask mode (if available) */
    516 	isa_outb(IO_ICU2 + PIC_OCW3, OCW3_SELECT | OCW3_SSMM | OCW3_SMM);
    517 	/* Read IRR by default. */
    518 	isa_outb(IO_ICU2 + PIC_OCW3, OCW3_SELECT | OCW3_RR);
    519 }
    520 
    521 
    522 /*
    523  *	SPEAKER BEEPER...
    524  */
    525 void
    526 sysbeepstop(void *arg)
    527 {
    528 	int s;
    529 
    530 	/* disable counter 2 */
    531 	s = splhigh();
    532 	isa_outb(PITAUX_PORT, isa_inb(PITAUX_PORT) & ~PIT_SPKR);
    533 	splx(s);
    534 	beeping = 0;
    535 }
    536 
    537 void
    538 sysbeep(int pitch, int period)
    539 {
    540 	static int last_pitch, last_period;
    541 	int s;
    542 
    543 	if (cold)
    544 		return;		/* Can't beep yet. */
    545 
    546 	if (beeping)
    547 		callout_stop(&sysbeep_ch);
    548 	if (!beeping || last_pitch != pitch) {
    549 		s = splhigh();
    550 		isa_outb(IO_TIMER1 + TIMER_MODE,
    551 		    TIMER_SEL2 | TIMER_16BIT | TIMER_SQWAVE);
    552 		isa_outb(IO_TIMER1 + TIMER_CNTR2, TIMER_DIV(pitch) % 256);
    553 		isa_outb(IO_TIMER1 + TIMER_CNTR2, TIMER_DIV(pitch) / 256);
    554 		isa_outb(PITAUX_PORT, isa_inb(PITAUX_PORT) | PIT_SPKR);
    555 		splx(s);
    556 	}
    557 	last_pitch = pitch;
    558 	beeping = last_period = period;
    559 	callout_reset(&sysbeep_ch, period, sysbeepstop, NULL);
    560 }
    561 
    562 int
    563 isa_intr_alloc(isa_chipset_tag_t c, int mask, int type, int *irq_p)
    564 {
    565 	int irq;
    566 	int maybe_irq = -1;
    567 	int shared_depth = 0;
    568 	mask &= 0x8b28; /* choose from 3, 5, 8, 9, 11, 15 XXX */
    569 	for (irq = 0; mask != 0; mask >>= 1, irq++) {
    570 		if ((mask & 1) == 0)
    571 			continue;
    572 		if (intrtype[irq] == IST_NONE) {
    573 			*irq_p = irq;
    574 			return 0;
    575 		}
    576 		/* Level interrupts can be shared */
    577 		if (type == IST_LEVEL && intrtype[irq] == IST_LEVEL) {
    578 			struct isa_intrhand *ih = isa_intrhand[irq];
    579 			int depth;
    580 			if (maybe_irq == -1) {
    581  				maybe_irq = irq;
    582 				continue;
    583 			}
    584 			for (depth = 0; ih != NULL; ih = ih->ih_next)
    585 				depth++;
    586 			if (depth < shared_depth) {
    587 				maybe_irq = irq;
    588 				shared_depth = depth;
    589 			}
    590 		}
    591 	}
    592 	if (maybe_irq != -1) {
    593 		*irq_p = maybe_irq;
    594 		return 0;
    595 	}
    596 	return 1;
    597 }
    598