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sio_pic.c revision 1.29.4.1
      1 /* $NetBSD: sio_pic.c,v 1.29.4.1 2001/08/03 04:10:48 lukem Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
      9  * NASA Ames Research Center.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. All advertising materials mentioning features or use of this software
     20  *    must display the following acknowledgement:
     21  *	This product includes software developed by the NetBSD
     22  *	Foundation, Inc. and its contributors.
     23  * 4. Neither the name of The NetBSD Foundation nor the names of its
     24  *    contributors may be used to endorse or promote products derived
     25  *    from this software without specific prior written permission.
     26  *
     27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     37  * POSSIBILITY OF SUCH DAMAGE.
     38  */
     39 
     40 /*
     41  * Copyright (c) 1995, 1996 Carnegie-Mellon University.
     42  * All rights reserved.
     43  *
     44  * Author: Chris G. Demetriou
     45  *
     46  * Permission to use, copy, modify and distribute this software and
     47  * its documentation is hereby granted, provided that both the copyright
     48  * notice and this permission notice appear in all copies of the
     49  * software, derivative works or modified versions, and any portions
     50  * thereof, and that both notices appear in supporting documentation.
     51  *
     52  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     53  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
     54  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     55  *
     56  * Carnegie Mellon requests users of this software to return to
     57  *
     58  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     59  *  School of Computer Science
     60  *  Carnegie Mellon University
     61  *  Pittsburgh PA 15213-3890
     62  *
     63  * any improvements or extensions that they make and grant Carnegie the
     64  * rights to redistribute these changes.
     65  */
     66 
     67 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
     68 
     69 __KERNEL_RCSID(0, "$NetBSD: sio_pic.c,v 1.29.4.1 2001/08/03 04:10:48 lukem Exp $");
     70 
     71 #include <sys/param.h>
     72 #include <sys/systm.h>
     73 #include <sys/device.h>
     74 #include <sys/malloc.h>
     75 #include <sys/syslog.h>
     76 
     77 #include <machine/intr.h>
     78 #include <machine/bus.h>
     79 
     80 #include <dev/pci/pcireg.h>
     81 #include <dev/pci/pcivar.h>
     82 #include <dev/pci/pcidevs.h>
     83 
     84 #include <dev/pci/cy82c693reg.h>
     85 #include <dev/pci/cy82c693var.h>
     86 
     87 #include <dev/isa/isareg.h>
     88 #include <dev/isa/isavar.h>
     89 #include <alpha/pci/siovar.h>
     90 
     91 #include "sio.h"
     92 
     93 /*
     94  * To add to the long history of wonderful PROM console traits,
     95  * AlphaStation PROMs don't reset themselves completely on boot!
     96  * Therefore, if an interrupt was turned on when the kernel was
     97  * started, we're not going to EVER turn it off...  I don't know
     98  * what will happen if new interrupts (that the PROM console doesn't
     99  * want) are turned on.  I'll burn that bridge when I come to it.
    100  */
    101 #define	BROKEN_PROM_CONSOLE
    102 
    103 /*
    104  * Private functions and variables.
    105  */
    106 
    107 bus_space_tag_t sio_iot;
    108 pci_chipset_tag_t sio_pc;
    109 bus_space_handle_t sio_ioh_icu1, sio_ioh_icu2;
    110 
    111 #define	ICU_LEN		16		/* number of ISA IRQs */
    112 
    113 static struct alpha_shared_intr *sio_intr;
    114 
    115 #ifndef STRAY_MAX
    116 #define	STRAY_MAX	5
    117 #endif
    118 
    119 #ifdef BROKEN_PROM_CONSOLE
    120 /*
    121  * If prom console is broken, must remember the initial interrupt
    122  * settings and enforce them.  WHEE!
    123  */
    124 #define	INITIALLY_ENABLED(irq)						\
    125 	((initial_ocw1[(irq) / 8] & (1 << ((irq) % 8))) == 0)
    126 #define	INITIALLY_LEVEL_TRIGGERED(irq)					\
    127 	((initial_elcr[(irq) / 8] & (1 << ((irq) % 8))) != 0)
    128 u_int8_t initial_ocw1[2];
    129 u_int8_t initial_elcr[2];
    130 #else
    131 #define	INITIALLY_ENABLED(irq)		((irq) == 2 ? 1 : 0)
    132 #define	INITIALLY_LEVEL_TRIGGERED(irq)	0
    133 #endif
    134 
    135 void		sio_setirqstat __P((int, int, int));
    136 
    137 u_int8_t	(*sio_read_elcr) __P((int));
    138 void		(*sio_write_elcr) __P((int, u_int8_t));
    139 static void	specific_eoi __P((int));
    140 #ifdef BROKEN_PROM_CONSOLE
    141 void		sio_intr_shutdown __P((void *));
    142 #endif
    143 
    144 /******************** i82378 SIO ELCR functions ********************/
    145 
    146 int		i82378_setup_elcr __P((void));
    147 u_int8_t	i82378_read_elcr __P((int));
    148 void		i82378_write_elcr __P((int, u_int8_t));
    149 
    150 bus_space_handle_t sio_ioh_elcr;
    151 
    152 int
    153 i82378_setup_elcr()
    154 {
    155 	int rv;
    156 
    157 	/*
    158 	 * We could probe configuration space to see that there's
    159 	 * actually an SIO present, but we are using this as a
    160 	 * fall-back in case nothing else matches.
    161 	 */
    162 
    163 	rv = bus_space_map(sio_iot, 0x4d0, 2, 0, &sio_ioh_elcr);
    164 
    165 	if (rv == 0) {
    166 		sio_read_elcr = i82378_read_elcr;
    167 		sio_write_elcr = i82378_write_elcr;
    168 	}
    169 
    170 	return (rv);
    171 }
    172 
    173 u_int8_t
    174 i82378_read_elcr(elcr)
    175 	int elcr;
    176 {
    177 
    178 	return (bus_space_read_1(sio_iot, sio_ioh_elcr, elcr));
    179 }
    180 
    181 void
    182 i82378_write_elcr(elcr, val)
    183 	int elcr;
    184 	u_int8_t val;
    185 {
    186 
    187 	bus_space_write_1(sio_iot, sio_ioh_elcr, elcr, val);
    188 }
    189 
    190 /******************** Cypress CY82C693 ELCR functions ********************/
    191 
    192 int		cy82c693_setup_elcr __P((void));
    193 u_int8_t	cy82c693_read_elcr __P((int));
    194 void		cy82c693_write_elcr __P((int, u_int8_t));
    195 
    196 const struct cy82c693_handle *sio_cy82c693_handle;
    197 
    198 int
    199 cy82c693_setup_elcr()
    200 {
    201 	int device, maxndevs;
    202 	pcitag_t tag;
    203 	pcireg_t id;
    204 
    205 	/*
    206 	 * Search PCI configuration space for a Cypress CY82C693.
    207 	 *
    208 	 * Note we can make some assumptions about our bus number
    209 	 * here, because:
    210 	 *
    211 	 *	(1) there can be at most one ISA/EISA bridge per PCI bus, and
    212 	 *
    213 	 *	(2) any ISA/EISA bridges must be attached to primary PCI
    214 	 *	    busses (i.e. bus zero).
    215 	 */
    216 
    217 	maxndevs = pci_bus_maxdevs(sio_pc, 0);
    218 
    219 	for (device = 0; device < maxndevs; device++) {
    220 		tag = pci_make_tag(sio_pc, 0, device, 0);
    221 		id = pci_conf_read(sio_pc, tag, PCI_ID_REG);
    222 
    223 		/* Invalid vendor ID value? */
    224 		if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
    225 			continue;
    226 		/* XXX Not invalid, but we've done this ~forever. */
    227 		if (PCI_VENDOR(id) == 0)
    228 			continue;
    229 
    230 		if (PCI_VENDOR(id) != PCI_VENDOR_CONTAQ ||
    231 		    PCI_PRODUCT(id) != PCI_PRODUCT_CONTAQ_82C693)
    232 			continue;
    233 
    234 		/*
    235 		 * Found one!
    236 		 */
    237 
    238 #if 0
    239 		printf("cy82c693_setup_elcr: found 82C693 at device %d\n",
    240 		    device);
    241 #endif
    242 
    243 		sio_cy82c693_handle = cy82c693_init(sio_iot);
    244 		sio_read_elcr = cy82c693_read_elcr;
    245 		sio_write_elcr = cy82c693_write_elcr;
    246 
    247 		return (0);
    248 	}
    249 
    250 	/*
    251 	 * Didn't find a CY82C693.
    252 	 */
    253 	return (ENODEV);
    254 }
    255 
    256 u_int8_t
    257 cy82c693_read_elcr(elcr)
    258 	int elcr;
    259 {
    260 
    261 	return (cy82c693_read(sio_cy82c693_handle, CONFIG_ELCR1 + elcr));
    262 }
    263 
    264 void
    265 cy82c693_write_elcr(elcr, val)
    266 	int elcr;
    267 	u_int8_t val;
    268 {
    269 
    270 	cy82c693_write(sio_cy82c693_handle, CONFIG_ELCR1 + elcr, val);
    271 }
    272 
    273 /******************** ELCR access function configuration ********************/
    274 
    275 /*
    276  * Put the Intel SIO at the end, so we fall back on it if we don't
    277  * find anything else.  If any of the non-Intel functions find a
    278  * matching device, but are unable to map it for whatever reason,
    279  * they should panic.
    280  */
    281 
    282 int (*sio_elcr_setup_funcs[]) __P((void)) = {
    283 	cy82c693_setup_elcr,
    284 	i82378_setup_elcr,
    285 	NULL,
    286 };
    287 
    288 /******************** Shared SIO/Cypress functions ********************/
    289 
    290 void
    291 sio_setirqstat(irq, enabled, type)
    292 	int irq, enabled;
    293 	int type;
    294 {
    295 	u_int8_t ocw1[2], elcr[2];
    296 	int icu, bit;
    297 
    298 #if 0
    299 	printf("sio_setirqstat: irq %d: %s, %s\n", irq,
    300 	    enabled ? "enabled" : "disabled", isa_intr_typename(type));
    301 #endif
    302 
    303 	icu = irq / 8;
    304 	bit = irq % 8;
    305 
    306 	ocw1[0] = bus_space_read_1(sio_iot, sio_ioh_icu1, 1);
    307 	ocw1[1] = bus_space_read_1(sio_iot, sio_ioh_icu2, 1);
    308 	elcr[0] = (*sio_read_elcr)(0);				/* XXX */
    309 	elcr[1] = (*sio_read_elcr)(1);				/* XXX */
    310 
    311 	/*
    312 	 * interrupt enable: set bit to mask (disable) interrupt.
    313 	 */
    314 	if (enabled)
    315 		ocw1[icu] &= ~(1 << bit);
    316 	else
    317 		ocw1[icu] |= 1 << bit;
    318 
    319 	/*
    320 	 * interrupt type select: set bit to get level-triggered.
    321 	 */
    322 	if (type == IST_LEVEL)
    323 		elcr[icu] |= 1 << bit;
    324 	else
    325 		elcr[icu] &= ~(1 << bit);
    326 
    327 #ifdef not_here
    328 	/* see the init function... */
    329 	ocw1[0] &= ~0x04;		/* always enable IRQ2 on first PIC */
    330 	elcr[0] &= ~0x07;		/* IRQ[0-2] must be edge-triggered */
    331 	elcr[1] &= ~0x21;		/* IRQ[13,8] must be edge-triggered */
    332 #endif
    333 
    334 	bus_space_write_1(sio_iot, sio_ioh_icu1, 1, ocw1[0]);
    335 	bus_space_write_1(sio_iot, sio_ioh_icu2, 1, ocw1[1]);
    336 	(*sio_write_elcr)(0, elcr[0]);				/* XXX */
    337 	(*sio_write_elcr)(1, elcr[1]);				/* XXX */
    338 }
    339 
    340 void
    341 sio_intr_setup(pc, iot)
    342 	pci_chipset_tag_t pc;
    343 	bus_space_tag_t iot;
    344 {
    345 	char *cp;
    346 	int i;
    347 
    348 	sio_iot = iot;
    349 	sio_pc = pc;
    350 
    351 	if (bus_space_map(sio_iot, IO_ICU1, 2, 0, &sio_ioh_icu1) ||
    352 	    bus_space_map(sio_iot, IO_ICU2, 2, 0, &sio_ioh_icu2))
    353 		panic("sio_intr_setup: can't map ICU I/O ports");
    354 
    355 	for (i = 0; sio_elcr_setup_funcs[i] != NULL; i++)
    356 		if ((*sio_elcr_setup_funcs[i])() == 0)
    357 			break;
    358 	if (sio_elcr_setup_funcs[i] == NULL)
    359 		panic("sio_intr_setup: can't map ELCR");
    360 
    361 #ifdef BROKEN_PROM_CONSOLE
    362 	/*
    363 	 * Remember the initial values, so we can restore them later.
    364 	 */
    365 	initial_ocw1[0] = bus_space_read_1(sio_iot, sio_ioh_icu1, 1);
    366 	initial_ocw1[1] = bus_space_read_1(sio_iot, sio_ioh_icu2, 1);
    367 	initial_elcr[0] = (*sio_read_elcr)(0);			/* XXX */
    368 	initial_elcr[1] = (*sio_read_elcr)(1);			/* XXX */
    369 	shutdownhook_establish(sio_intr_shutdown, 0);
    370 #endif
    371 
    372 	sio_intr = alpha_shared_intr_alloc(ICU_LEN, 8);
    373 
    374 	/*
    375 	 * set up initial values for interrupt enables.
    376 	 */
    377 	for (i = 0; i < ICU_LEN; i++) {
    378 		alpha_shared_intr_set_maxstrays(sio_intr, i, STRAY_MAX);
    379 
    380 		cp = alpha_shared_intr_string(sio_intr, i);
    381 		sprintf(cp, "irq %d", i);
    382 		evcnt_attach_dynamic(alpha_shared_intr_evcnt(sio_intr, i),
    383 		    EVCNT_TYPE_INTR, NULL, "isa", cp);
    384 
    385 		switch (i) {
    386 		case 0:
    387 		case 1:
    388 		case 8:
    389 		case 13:
    390 			/*
    391 			 * IRQs 0, 1, 8, and 13 must always be
    392 			 * edge-triggered.
    393 			 */
    394 			if (INITIALLY_LEVEL_TRIGGERED(i))
    395 				printf("sio_intr_setup: %d level-triggered\n",
    396 				    i);
    397 			sio_setirqstat(i, INITIALLY_ENABLED(i), IST_EDGE);
    398 			alpha_shared_intr_set_dfltsharetype(sio_intr, i,
    399 			    IST_EDGE);
    400 			specific_eoi(i);
    401 			break;
    402 
    403 		case 2:
    404 			/*
    405 			 * IRQ 2 must be edge-triggered, and should be
    406 			 * enabled (otherwise IRQs 8-15 are ignored).
    407 			 */
    408 			sio_setirqstat(i, 1, IST_EDGE);
    409 			alpha_shared_intr_set_dfltsharetype(sio_intr, i,
    410 			    IST_UNUSABLE);
    411 			break;
    412 
    413 		default:
    414 			/*
    415 			 * Otherwise, disable the IRQ and set its
    416 			 * type to (effectively) "unknown."
    417 			 */
    418 			sio_setirqstat(i, INITIALLY_ENABLED(i),
    419 			    INITIALLY_LEVEL_TRIGGERED(i) ?
    420 			    IST_LEVEL : IST_NONE);
    421 			alpha_shared_intr_set_dfltsharetype(sio_intr, i,
    422 			    INITIALLY_LEVEL_TRIGGERED(i) ?
    423 			    IST_LEVEL : IST_NONE);
    424 			specific_eoi(i);
    425 			break;
    426 		}
    427 	}
    428 }
    429 
    430 #ifdef BROKEN_PROM_CONSOLE
    431 void
    432 sio_intr_shutdown(arg)
    433 	void *arg;
    434 {
    435 	/*
    436 	 * Restore the initial values, to make the PROM happy.
    437 	 */
    438 	bus_space_write_1(sio_iot, sio_ioh_icu1, 1, initial_ocw1[0]);
    439 	bus_space_write_1(sio_iot, sio_ioh_icu2, 1, initial_ocw1[1]);
    440 	(*sio_write_elcr)(0, initial_elcr[0]);			/* XXX */
    441 	(*sio_write_elcr)(1, initial_elcr[1]);			/* XXX */
    442 }
    443 #endif
    444 
    445 const char *
    446 sio_intr_string(v, irq)
    447 	void *v;
    448 	int irq;
    449 {
    450 	static char irqstr[12];		/* 8 + 2 + NULL + sanity */
    451 
    452 	if (irq == 0 || irq >= ICU_LEN || irq == 2)
    453 		panic("sio_intr_string: bogus isa irq 0x%x\n", irq);
    454 
    455 	sprintf(irqstr, "isa irq %d", irq);
    456 	return (irqstr);
    457 }
    458 
    459 const struct evcnt *
    460 sio_intr_evcnt(v, irq)
    461 	void *v;
    462 	int irq;
    463 {
    464 
    465 	if (irq == 0 || irq >= ICU_LEN || irq == 2)
    466 		panic("sio_intr_evcnt: bogus isa irq 0x%x\n", irq);
    467 
    468 	return (alpha_shared_intr_evcnt(sio_intr, irq));
    469 }
    470 
    471 void *
    472 sio_intr_establish(v, irq, type, level, fn, arg)
    473 	void *v, *arg;
    474         int irq;
    475         int type;
    476         int level;
    477         int (*fn)(void *);
    478 {
    479 	void *cookie;
    480 
    481 	if (irq > ICU_LEN || type == IST_NONE)
    482 		panic("sio_intr_establish: bogus irq or type");
    483 
    484 	cookie = alpha_shared_intr_establish(sio_intr, irq, type, level, fn,
    485 	    arg, "isa irq");
    486 
    487 	if (cookie != NULL &&
    488 	    alpha_shared_intr_firstactive(sio_intr, irq)) {
    489 		scb_set(0x800 + SCB_IDXTOVEC(irq), sio_iointr, NULL);
    490 		sio_setirqstat(irq, 1,
    491 		    alpha_shared_intr_get_sharetype(sio_intr, irq));
    492 	}
    493 
    494 	return (cookie);
    495 }
    496 
    497 void
    498 sio_intr_disestablish(v, cookie)
    499 	void *v;
    500 	void *cookie;
    501 {
    502 	struct alpha_shared_intrhand *ih = cookie;
    503 	int s, ist, irq = ih->ih_num;
    504 
    505 	s = splhigh();
    506 
    507 	/* Remove it from the link. */
    508 	alpha_shared_intr_disestablish(sio_intr, cookie, "isa irq");
    509 
    510 	/*
    511 	 * Decide if we should disable the interrupt.  We must ensure
    512 	 * that:
    513 	 *
    514 	 *	- An initially-enabled interrupt is never disabled.
    515 	 *	- An initially-LT interrupt is never untyped.
    516 	 */
    517 	if (alpha_shared_intr_isactive(sio_intr, irq) == 0) {
    518 		/*
    519 		 * IRQs 0, 1, 8, and 13 must always be edge-triggered
    520 		 * (see setup).
    521 		 */
    522 		switch (irq) {
    523 		case 0:
    524 		case 1:
    525 		case 8:
    526 		case 13:
    527 			/*
    528 			 * If the interrupt was initially level-triggered
    529 			 * a warning was printed in setup.
    530 			 */
    531 			ist = IST_EDGE;
    532 			break;
    533 
    534 		default:
    535 			ist = INITIALLY_LEVEL_TRIGGERED(irq) ?
    536 			    IST_LEVEL : IST_NONE;
    537 			break;
    538 		}
    539 		sio_setirqstat(irq, INITIALLY_ENABLED(irq), ist);
    540 		alpha_shared_intr_set_dfltsharetype(sio_intr, irq, ist);
    541 
    542 		/* Release our SCB vector. */
    543 		scb_free(0x800 + SCB_IDXTOVEC(irq));
    544 	}
    545 
    546 	splx(s);
    547 }
    548 
    549 void
    550 sio_iointr(arg, vec)
    551 	void *arg;
    552 	unsigned long vec;
    553 {
    554 	int irq;
    555 
    556 	irq = SCB_VECTOIDX(vec - 0x800);
    557 
    558 #ifdef DIAGNOSTIC
    559 	if (irq > ICU_LEN || irq < 0)
    560 		panic("sio_iointr: irq out of range (%d)", irq);
    561 #endif
    562 
    563 	if (!alpha_shared_intr_dispatch(sio_intr, irq))
    564 		alpha_shared_intr_stray(sio_intr, irq, "isa irq");
    565 
    566 	/*
    567 	 * Some versions of the machines which use the SIO
    568 	 * (or is it some PALcode revisions on those machines?)
    569 	 * require the non-specific EOI to be fed to the PIC(s)
    570 	 * by the interrupt handler.
    571 	 */
    572 	specific_eoi(irq);
    573 }
    574 
    575 #define	LEGAL_IRQ(x)	((x) >= 0 && (x) < ICU_LEN && (x) != 2)
    576 
    577 int
    578 sio_intr_alloc(v, mask, type, irq)
    579 	void *v;
    580 	int mask;
    581 	int type;
    582 	int *irq;
    583 {
    584 	int i, tmp, bestirq, count;
    585 	struct alpha_shared_intrhand **p, *q;
    586 
    587 	if (type == IST_NONE)
    588 		panic("intr_alloc: bogus type");
    589 
    590 	bestirq = -1;
    591 	count = -1;
    592 
    593 	/* some interrupts should never be dynamically allocated */
    594 	mask &= 0xdef8;
    595 
    596 	/*
    597 	 * XXX some interrupts will be used later (6 for fdc, 12 for pms).
    598 	 * the right answer is to do "breadth-first" searching of devices.
    599 	 */
    600 	mask &= 0xefbf;
    601 
    602 	for (i = 0; i < ICU_LEN; i++) {
    603 		if (LEGAL_IRQ(i) == 0 || (mask & (1<<i)) == 0)
    604 			continue;
    605 
    606 		switch(sio_intr[i].intr_sharetype) {
    607 		case IST_NONE:
    608 			/*
    609 			 * if nothing's using the irq, just return it
    610 			 */
    611 			*irq = i;
    612 			return (0);
    613 
    614 		case IST_EDGE:
    615 		case IST_LEVEL:
    616 			if (type != sio_intr[i].intr_sharetype)
    617 				continue;
    618 			/*
    619 			 * if the irq is shareable, count the number of other
    620 			 * handlers, and if it's smaller than the last irq like
    621 			 * this, remember it
    622 			 *
    623 			 * XXX We should probably also consider the
    624 			 * interrupt level and stick IPL_TTY with other
    625 			 * IPL_TTY, etc.
    626 			 */
    627 			for (p = &TAILQ_FIRST(&sio_intr[i].intr_q), tmp = 0;
    628 			     (q = *p) != NULL; p = &TAILQ_NEXT(q, ih_q), tmp++)
    629 				;
    630 			if ((bestirq == -1) || (count > tmp)) {
    631 				bestirq = i;
    632 				count = tmp;
    633 			}
    634 			break;
    635 
    636 		case IST_PULSE:
    637 			/* this just isn't shareable */
    638 			continue;
    639 		}
    640 	}
    641 
    642 	if (bestirq == -1)
    643 		return (1);
    644 
    645 	*irq = bestirq;
    646 
    647 	return (0);
    648 }
    649 
    650 static void
    651 specific_eoi(irq)
    652 	int irq;
    653 {
    654 	if (irq > 7)
    655 		bus_space_write_1(sio_iot,
    656 		    sio_ioh_icu2, 0, 0x20 | (irq & 0x07));	/* XXX */
    657 	bus_space_write_1(sio_iot, sio_ioh_icu1, 0, 0x20 | (irq > 7 ? 2 : irq));
    658 }
    659