xref: /netbsd-src/sys/arch/i386/pci/pcibios.c (revision 4b896b232495b7a9b8b94a1cf1e21873296d53b8)
1 /*	$NetBSD: pcibios.c,v 1.19 2004/05/03 07:08:46 kochi Exp $	*/
2 
3 /*-
4  * Copyright (c) 1999 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) 1999, by UCHIYAMA Yasushi
42  * All rights reserved.
43  *
44  * Redistribution and use in source and binary forms, with or without
45  * modification, are permitted provided that the following conditions
46  * are met:
47  * 1. Redistributions of source code must retain the above copyright
48  *    notice, this list of conditions and the following disclaimer.
49  * 2. The name of the developer may NOT be used to endorse or promote products
50  *    derived from this software without specific prior written permission.
51  *
52  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62  * SUCH DAMAGE.
63  */
64 
65 /*
66  * Interface to the PCI BIOS and PCI Interrupt Routing table.
67  */
68 
69 #include <sys/cdefs.h>
70 __KERNEL_RCSID(0, "$NetBSD: pcibios.c,v 1.19 2004/05/03 07:08:46 kochi Exp $");
71 
72 #include "opt_pcibios.h"
73 
74 #include <sys/param.h>
75 #include <sys/systm.h>
76 #include <sys/device.h>
77 #include <sys/malloc.h>
78 
79 #include <dev/isa/isareg.h>
80 #include <machine/isa_machdep.h>
81 
82 #include <dev/pci/pcireg.h>
83 #include <dev/pci/pcivar.h>
84 #include <dev/pci/pcidevs.h>
85 
86 #include <i386/pci/pcibios.h>
87 #ifdef PCIBIOS_INTR_FIXUP
88 #include <i386/pci/pci_intr_fixup.h>
89 #endif
90 #ifdef PCIBIOS_BUS_FIXUP
91 #include <i386/pci/pci_bus_fixup.h>
92 #endif
93 #ifdef PCIBIOS_ADDR_FIXUP
94 #include <i386/pci/pci_addr_fixup.h>
95 #endif
96 
97 #include <machine/bios32.h>
98 
99 #ifdef PCIBIOSVERBOSE
100 int	pcibiosverbose = 1;
101 #endif
102 
103 int pcibios_present;
104 
105 struct pcibios_pir_header pcibios_pir_header;
106 struct pcibios_intr_routing *pcibios_pir_table;
107 int pcibios_pir_table_nentries;
108 int pcibios_max_bus;
109 
110 struct bios32_entry pcibios_entry;
111 
112 void	pcibios_pir_init(void);
113 
114 int	pcibios_get_status(u_int32_t *, u_int32_t *, u_int32_t *,
115 	    u_int32_t *, u_int32_t *, u_int32_t *, u_int32_t *);
116 int	pcibios_get_intr_routing(struct pcibios_intr_routing *,
117 	    int *, u_int16_t *);
118 
119 int	pcibios_return_code(u_int16_t, const char *);
120 
121 void	pcibios_print_exclirq(void);
122 
123 #ifdef PCIBIOS_LIBRETTO_FIXUP
124 /* for Libretto L2/L3 hack */
125 static void	pcibios_fixup_pir_table(void);
126 static void	pcibios_fixup_pir_table_mask(struct pcibios_linkmap *);
127 
128 struct pcibios_linkmap pir_mask[] = {
129 	{ 2,	0x0040 },
130 	{ 7,	0x0080 },
131 	{ 8,	0x0020 },
132 	{ 0,	0x0000 }
133 };
134 #endif
135 
136 #ifdef PCIINTR_DEBUG
137 void	pcibios_print_pir_table(void);
138 #endif
139 
140 #define	PCI_IRQ_TABLE_START	0xf0000
141 #define	PCI_IRQ_TABLE_END	0xfffff
142 
143 static void pci_bridge_hook(pci_chipset_tag_t, pcitag_t, void *);
144 struct pci_bridge_hook_arg {
145 	void (*func)(pci_chipset_tag_t, pcitag_t, void *);
146 	void *arg;
147 };
148 
149 void
150 pcibios_init()
151 {
152 	struct bios32_entry_info ei;
153 	u_int32_t rev_maj, rev_min, mech1, mech2, scmech1, scmech2;
154 
155 	if (bios32_service(BIOS32_MAKESIG('$', 'P', 'C', 'I'),
156 	    &pcibios_entry, &ei) == 0) {
157 		/*
158 		 * No PCI BIOS found; will fall back on old
159 		 * mechanism.
160 		 */
161 		return;
162 	}
163 
164 	/*
165 	 * We've located the PCI BIOS service; get some information
166 	 * about it.
167 	 */
168 	if (pcibios_get_status(&rev_maj, &rev_min, &mech1, &mech2,
169 	    &scmech1, &scmech2, &pcibios_max_bus) != PCIBIOS_SUCCESS) {
170 		/*
171 		 * We can't use the PCI BIOS; will fall back on old
172 		 * mechanism.
173 		 */
174 		return;
175 	}
176 
177 	printf("PCI BIOS rev. %d.%d found at 0x%lx\n", rev_maj, rev_min >> 4,
178 	    ei.bei_entry);
179 #ifdef PCIBIOSVERBOSE
180 	printf("pcibios: config mechanism %s%s, special cycles %s%s, "
181 	    "last bus %d\n",
182 	    mech1 ? "[1]" : "[x]",
183 	    mech2 ? "[2]" : "[x]",
184 	    scmech1 ? "[1]" : "[x]",
185 	    scmech2 ? "[2]" : "[x]",
186 	    pcibios_max_bus);
187 
188 #endif
189 
190 	/*
191 	 * The PCI BIOS tells us the config mechanism; fill it in now
192 	 * so that pci_mode_detect() doesn't have to look for it.
193 	 */
194 	pci_mode = mech1 ? 1 : 2;
195 
196 	pcibios_present = 1;
197 
198 	/*
199 	 * Find the PCI IRQ Routing table.
200 	 */
201 	pcibios_pir_init();
202 
203 #ifdef PCIBIOS_INTR_FIXUP
204 	if (pcibios_pir_table != NULL) {
205 		int rv;
206 		u_int16_t pciirq;
207 
208 		/*
209 		 * Fixup interrupt routing.
210 		 */
211 		rv = pci_intr_fixup(NULL, X86_BUS_SPACE_IO, &pciirq);
212 		switch (rv) {
213 		case -1:
214 			/* Non-fatal error. */
215 			printf("Warning: unable to fix up PCI interrupt "
216 			    "routing\n");
217 			break;
218 
219 		case 1:
220 			/* Fatal error. */
221 			panic("pcibios_init: interrupt fixup failed");
222 			break;
223 		}
224 
225 		/*
226 		 * XXX Clear `pciirq' from the ISA interrupt allocation
227 		 * XXX mask.
228 		 */
229 	}
230 #endif
231 
232 #ifdef PCIBIOS_BUS_FIXUP
233 	pcibios_max_bus = pci_bus_fixup(NULL, 0);
234 #ifdef PCIBIOSVERBOSE
235 	printf("PCI bus #%d is the last bus\n", pcibios_max_bus);
236 #endif
237 #endif
238 
239 #ifdef PCIBIOS_ADDR_FIXUP
240 	pci_addr_fixup(NULL, pcibios_max_bus);
241 #endif
242 }
243 
244 void
245 pcibios_pir_init()
246 {
247 	char *devinfo;
248 	paddr_t pa;
249 	caddr_t p;
250 	unsigned char cksum;
251 	u_int16_t tablesize;
252 	u_int8_t rev_maj, rev_min;
253 	int i;
254 
255 	for (pa = PCI_IRQ_TABLE_START; pa < PCI_IRQ_TABLE_END; pa += 16) {
256 		p = (caddr_t)ISA_HOLE_VADDR(pa);
257 		if (*(int *)p != BIOS32_MAKESIG('$', 'P', 'I', 'R')) {
258 			/*
259 			 * XXX: Some laptops (Toshiba/Libretto L series)
260 			 * use _PIR instead of $PIR. So we try that too.
261 			 */
262 			if (*(int *)p != BIOS32_MAKESIG('_', 'P', 'I', 'R'))
263 				continue;
264 		}
265 
266 		rev_min = *(p + 4);
267 		rev_maj = *(p + 5);
268 		tablesize = *(u_int16_t *)(p + 6);
269 
270 		cksum = 0;
271 		for (i = 0; i < tablesize; i++)
272 			cksum += *(unsigned char *)(p + i);
273 
274 		printf("PCI IRQ Routing Table rev. %d.%d found at 0x%lx, "
275 		    "size %d bytes (%d entries)\n", rev_maj, rev_min, pa,
276 		    tablesize, (tablesize - 32) / 16);
277 
278 		if (cksum != 0) {
279 			printf("pcibios_pir_init: bad IRQ table checksum\n");
280 			continue;
281 		}
282 
283 		if (tablesize < 32 || (tablesize % 16) != 0) {
284 			printf("pcibios_pir_init: bad IRQ table size\n");
285 			continue;
286 		}
287 
288 		if (rev_maj != 1 || rev_min != 0) {
289 			printf("pcibios_pir_init: unsupported IRQ table "
290 			    "version\n");
291 			continue;
292 		}
293 
294 		/*
295 		 * We can handle this table!  Make a copy of it.
296 		 */
297 		memcpy(&pcibios_pir_header, p, 32);
298 		pcibios_pir_table = malloc(tablesize - 32, M_DEVBUF,
299 		    M_NOWAIT);
300 		if (pcibios_pir_table == NULL) {
301 			printf("pcibios_pir_init: no memory for $PIR\n");
302 			return;
303 		}
304 		memcpy(pcibios_pir_table, p + 32, tablesize - 32);
305 		pcibios_pir_table_nentries = (tablesize - 32) / 16;
306 
307 		printf("PCI Interrupt Router at %03d:%02d:%01d",
308 		    pcibios_pir_header.router_bus,
309 		    PIR_DEVFUNC_DEVICE(pcibios_pir_header.router_devfunc),
310 		    PIR_DEVFUNC_FUNCTION(pcibios_pir_header.router_devfunc));
311 		if (pcibios_pir_header.compat_router != 0) {
312 			devinfo = malloc(256, M_DEVBUF, M_NOWAIT);
313 			if (devinfo) {
314 				pci_devinfo(pcibios_pir_header.compat_router,
315 				    0, 0, devinfo, 256);
316 				printf(" (%s compatible)", devinfo);
317 				free(devinfo, M_DEVBUF);
318 			}
319 		}
320 		printf("\n");
321 		pcibios_print_exclirq();
322 
323 #ifdef PCIBIOS_LIBRETTO_FIXUP
324 		/* for Libretto L2/L3 hack */
325 		pcibios_fixup_pir_table();
326 #endif
327 #ifdef PCIINTR_DEBUG
328 		pcibios_print_pir_table();
329 #endif
330 		return;
331 	}
332 
333 	/*
334 	 * If there was no PIR table found, try using the PCI BIOS
335 	 * Get Interrupt Routing call.
336 	 *
337 	 * XXX The interface to this call sucks; just allocate enough
338 	 * XXX room for 32 entries.
339 	 */
340 	pcibios_pir_table_nentries = 32;
341 	pcibios_pir_table = malloc(pcibios_pir_table_nentries *
342 	    sizeof(*pcibios_pir_table), M_DEVBUF, M_NOWAIT);
343 	if (pcibios_pir_table == NULL) {
344 		printf("pcibios_pir_init: no memory for $PIR\n");
345 		return;
346 	}
347 	if (pcibios_get_intr_routing(pcibios_pir_table,
348 	    &pcibios_pir_table_nentries,
349 	    &pcibios_pir_header.exclusive_irq) != PCIBIOS_SUCCESS) {
350 		printf("No PCI IRQ Routing information available.\n");
351 		free(pcibios_pir_table, M_DEVBUF);
352 		pcibios_pir_table = NULL;
353 		pcibios_pir_table_nentries = 0;
354 		return;
355 	}
356 	printf("PCI BIOS has %d Interrupt Routing table entries\n",
357 	    pcibios_pir_table_nentries);
358 	pcibios_print_exclirq();
359 
360 #ifdef PCIBIOS_LIBRETTO_FIXUP
361 	/* for Libretto L2/L3 hack */
362 	pcibios_fixup_pir_table();
363 #endif
364 #ifdef PCIINTR_DEBUG
365 	pcibios_print_pir_table();
366 #endif
367 }
368 
369 int
370 pcibios_get_status(u_int32_t *rev_maj, u_int32_t *rev_min,
371     u_int32_t *mech1, u_int32_t *mech2, u_int32_t *scmech1, u_int32_t *scmech2,
372     u_int32_t *maxbus)
373 {
374 	u_int16_t ax, bx, cx;
375 	u_int32_t edx;
376 	int rv;
377 
378 	__asm __volatile("lcall *(%%edi)				; \
379 			jc 1f						; \
380 			xor %%ah, %%ah					; \
381 		1:"
382 		: "=a" (ax), "=b" (bx), "=c" (cx), "=d" (edx)
383 		: "0" (0xb101), "D" (&pcibios_entry));
384 
385 	rv = pcibios_return_code(ax, "pcibios_get_status");
386 	if (rv != PCIBIOS_SUCCESS)
387 		return (rv);
388 
389 	if (edx != BIOS32_MAKESIG('P', 'C', 'I', ' '))
390 		return (PCIBIOS_SERVICE_NOT_PRESENT);	/* XXX */
391 
392 	/*
393 	 * Fill in the various pieces if info we're looking for.
394 	 */
395 	*mech1 = ax & 1;
396 	*mech2 = ax & (1 << 1);
397 	*scmech1 = ax & (1 << 4);
398 	*scmech2 = ax & (1 << 5);
399 	*rev_maj = (bx >> 8) & 0xff;
400 	*rev_min = bx & 0xff;
401 	*maxbus = cx & 0xff;
402 
403 	return (PCIBIOS_SUCCESS);
404 }
405 
406 int
407 pcibios_get_intr_routing(struct pcibios_intr_routing *table,
408     int *nentries, u_int16_t *exclirq)
409 {
410 	u_int16_t ax, bx;
411 	int rv;
412 	struct {
413 		u_int16_t size;
414 		caddr_t offset;
415 		u_int16_t segment;
416 	} __attribute__((__packed__)) args;
417 
418 	args.size = *nentries * sizeof(*table);
419 	args.offset = (caddr_t)table;
420 	args.segment = GSEL(GDATA_SEL, SEL_KPL);
421 
422 	memset(table, 0, args.size);
423 
424 	__asm __volatile("lcall *(%%esi)				; \
425 			jc 1f						; \
426 			xor %%ah, %%ah					; \
427 		1:	movw %w2, %%ds					; \
428 			movw %w2, %%es"
429 		: "=a" (ax), "=b" (bx)
430 		: "r" GSEL(GDATA_SEL, SEL_KPL), "0" (0xb10e), "1" (0),
431 		  "D" (&args), "S" (&pcibios_entry));
432 
433 	rv = pcibios_return_code(ax, "pcibios_get_intr_routing");
434 	if (rv != PCIBIOS_SUCCESS)
435 		return (rv);
436 
437 	*nentries = args.size / sizeof(*table);
438 	*exclirq = bx;
439 
440 	return (PCIBIOS_SUCCESS);
441 }
442 
443 int
444 pcibios_return_code(u_int16_t ax, const char *func)
445 {
446 	const char *errstr;
447 	int rv = ax >> 8;
448 
449 	switch (rv) {
450 	case PCIBIOS_SUCCESS:
451 		return (PCIBIOS_SUCCESS);
452 
453 	case PCIBIOS_SERVICE_NOT_PRESENT:
454 		errstr = "service not present";
455 		break;
456 
457 	case PCIBIOS_FUNCTION_NOT_SUPPORTED:
458 		errstr = "function not supported";
459 		break;
460 
461 	case PCIBIOS_BAD_VENDOR_ID:
462 		errstr = "bad vendor ID";
463 		break;
464 
465 	case PCIBIOS_DEVICE_NOT_FOUND:
466 		errstr = "device not found";
467 		break;
468 
469 	case PCIBIOS_BAD_REGISTER_NUMBER:
470 		errstr = "bad register number";
471 		break;
472 
473 	case PCIBIOS_SET_FAILED:
474 		errstr = "set failed";
475 		break;
476 
477 	case PCIBIOS_BUFFER_TOO_SMALL:
478 		errstr = "buffer too small";
479 		break;
480 
481 	default:
482 		printf("%s: unknown return code 0x%x\n", func, rv);
483 		return (rv);
484 	}
485 
486 	printf("%s: %s\n", func, errstr);
487 	return (rv);
488 }
489 
490 void
491 pcibios_print_exclirq()
492 {
493 	int i;
494 
495 	if (pcibios_pir_header.exclusive_irq) {
496 		printf("PCI Exclusive IRQs:");
497 		for (i = 0; i < 16; i++) {
498 			if (pcibios_pir_header.exclusive_irq & (1 << i))
499 				printf(" %d", i);
500 		}
501 		printf("\n");
502 	}
503 }
504 
505 #ifdef PCIBIOS_LIBRETTO_FIXUP
506 /* for Libretto L2/L3 hack */
507 static void
508 pcibios_fixup_pir_table()
509 {
510 	struct pcibios_linkmap *m;
511 
512 	for (m = pir_mask; m->link != 0; m++)
513 		pcibios_fixup_pir_table_mask(m);
514 }
515 
516 void
517 pcibios_fixup_pir_table_mask(mask)
518 	struct pcibios_linkmap *mask;
519 {
520 	int i, j;
521 
522 	for (i = 0; i < pcibios_pir_table_nentries; i++) {
523 		for (j = 0; j < 4; j++) {
524 			if (pcibios_pir_table[i].linkmap[j].link == mask->link) {
525 				pcibios_pir_table[i].linkmap[j].bitmap
526 				    &= mask->bitmap;
527 			}
528 		}
529 	}
530 }
531 #endif
532 
533 #ifdef PCIINTR_DEBUG
534 void
535 pcibios_print_pir_table()
536 {
537 	int i, j;
538 
539 	for (i = 0; i < pcibios_pir_table_nentries; i++) {
540 		printf("PIR Entry %d:\n", i);
541 		printf("\tBus: %d  Device: %d\n",
542 		    pcibios_pir_table[i].bus,
543 		    PIR_DEVFUNC_DEVICE(pcibios_pir_table[i].device));
544 		for (j = 0; j < 4; j++) {
545 			printf("\t\tINT%c: link 0x%02x bitmap 0x%04x\n",
546 			    'A' + j,
547 			    pcibios_pir_table[i].linkmap[j].link,
548 			    pcibios_pir_table[i].linkmap[j].bitmap);
549 		}
550 	}
551 }
552 #endif
553 
554 void
555 pci_device_foreach(pci_chipset_tag_t pc, int maxbus,
556     void (*func)(pci_chipset_tag_t, pcitag_t, void *), void *context)
557 {
558 	pci_device_foreach_min(pc, 0, maxbus, func, context);
559 }
560 
561 void
562 pci_device_foreach_min(pci_chipset_tag_t pc, int minbus, int maxbus,
563     void (*func)(pci_chipset_tag_t, pcitag_t, void *), void *context)
564 {
565 	const struct pci_quirkdata *qd;
566 	int bus, device, function, maxdevs, nfuncs;
567 	pcireg_t id, bhlcr;
568 	pcitag_t tag;
569 
570 	for (bus = minbus; bus <= maxbus; bus++) {
571 		maxdevs = pci_bus_maxdevs(pc, bus);
572 		for (device = 0; device < maxdevs; device++) {
573 			tag = pci_make_tag(pc, bus, device, 0);
574 			id = pci_conf_read(pc, tag, PCI_ID_REG);
575 
576 			/* Invalid vendor ID value? */
577 			if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
578 				continue;
579 			/* XXX Not invalid, but we've done this ~forever. */
580 			if (PCI_VENDOR(id) == 0)
581 				continue;
582 
583 			qd = pci_lookup_quirkdata(PCI_VENDOR(id),
584 			    PCI_PRODUCT(id));
585 
586 			bhlcr = pci_conf_read(pc, tag, PCI_BHLC_REG);
587 			if (PCI_HDRTYPE_MULTIFN(bhlcr) ||
588 			    (qd != NULL &&
589 			     (qd->quirks & PCI_QUIRK_MULTIFUNCTION) != 0))
590 				nfuncs = 8;
591 			else
592 				nfuncs = 1;
593 
594 			for (function = 0; function < nfuncs; function++) {
595 				tag = pci_make_tag(pc, bus, device, function);
596 				id = pci_conf_read(pc, tag, PCI_ID_REG);
597 
598 				/* Invalid vendor ID value? */
599 				if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
600 					continue;
601 				/*
602 				 * XXX Not invalid, but we've done this
603 				 * ~forever.
604 				 */
605 				if (PCI_VENDOR(id) == 0)
606 					continue;
607 				(*func)(pc, tag, context);
608 			}
609 		}
610 	}
611 }
612 
613 void
614 pci_bridge_foreach(pci_chipset_tag_t pc, int minbus, int maxbus,
615     void (*func)(pci_chipset_tag_t, pcitag_t, void *), void *ctx)
616 {
617 	struct pci_bridge_hook_arg bridge_hook;
618 
619 	bridge_hook.func = func;
620 	bridge_hook.arg = ctx;
621 
622 	pci_device_foreach_min(pc, minbus, maxbus, pci_bridge_hook,
623 	    &bridge_hook);
624 }
625 
626 void
627 pci_bridge_hook(pci_chipset_tag_t pc, pcitag_t tag, void *ctx)
628 {
629 	struct pci_bridge_hook_arg *bridge_hook = (void *)ctx;
630 	pcireg_t reg;
631 
632 	reg = pci_conf_read(pc, tag, PCI_CLASS_REG);
633 	if (PCI_CLASS(reg) == PCI_CLASS_BRIDGE &&
634 	    (PCI_SUBCLASS(reg) == PCI_SUBCLASS_BRIDGE_PCI ||
635 		PCI_SUBCLASS(reg) == PCI_SUBCLASS_BRIDGE_CARDBUS)) {
636 		(*bridge_hook->func)(pc, tag, bridge_hook->arg);
637 	}
638 }
639