xref: /netbsd-src/sys/arch/x86/pci/pci_machdep.c (revision fad4c9f71477ae11cea2ee75ec82151ac770a534)
1 /*	$NetBSD: pci_machdep.c,v 1.15 2006/06/25 03:46:56 soren Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997, 1998 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) 1996 Christopher G. Demetriou.  All rights reserved.
42  * Copyright (c) 1994 Charles M. Hannum.  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. Redistributions in binary form must reproduce the above copyright
50  *    notice, this list of conditions and the following disclaimer in the
51  *    documentation and/or other materials provided with the distribution.
52  * 3. All advertising materials mentioning features or use of this software
53  *    must display the following acknowledgement:
54  *	This product includes software developed by Charles M. Hannum.
55  * 4. The name of the author may not be used to endorse or promote products
56  *    derived from this software without specific prior written permission.
57  *
58  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
59  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
60  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
61  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
62  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
63  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
64  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
65  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
66  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
67  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
68  */
69 
70 /*
71  * Machine-specific functions for PCI autoconfiguration.
72  *
73  * On PCs, there are two methods of generating PCI configuration cycles.
74  * We try to detect the appropriate mechanism for this machine and set
75  * up a few function pointers to access the correct method directly.
76  *
77  * The configuration method can be hard-coded in the config file by
78  * using `options PCI_CONF_MODE=N', where `N' is the configuration mode
79  * as defined section 3.6.4.1, `Generating Configuration Cycles'.
80  */
81 
82 #include <sys/cdefs.h>
83 __KERNEL_RCSID(0, "$NetBSD: pci_machdep.c,v 1.15 2006/06/25 03:46:56 soren Exp $");
84 
85 #include <sys/types.h>
86 #include <sys/param.h>
87 #include <sys/time.h>
88 #include <sys/systm.h>
89 #include <sys/errno.h>
90 #include <sys/device.h>
91 #include <sys/lock.h>
92 
93 #include <uvm/uvm_extern.h>
94 
95 #include <machine/bus.h>
96 #include <machine/bus_private.h>
97 
98 #include <machine/pio.h>
99 
100 #include <dev/isa/isareg.h>
101 #include <dev/isa/isavar.h>
102 #include <dev/pci/pcivar.h>
103 #include <dev/pci/pcireg.h>
104 #include <dev/pci/pcidevs.h>
105 
106 #include "opt_mpbios.h"
107 #include "opt_mpacpi.h"
108 
109 #ifdef MPBIOS
110 #include <machine/mpbiosvar.h>
111 #endif
112 
113 #ifdef MPACPI
114 #include <machine/mpacpi.h>
115 #endif
116 
117 #include "opt_pci_conf_mode.h"
118 
119 int pci_mode = -1;
120 
121 static void pci_bridge_hook(pci_chipset_tag_t, pcitag_t, void *);
122 struct pci_bridge_hook_arg {
123 	void (*func)(pci_chipset_tag_t, pcitag_t, void *);
124 	void *arg;
125 };
126 
127 
128 struct simplelock pci_conf_slock = SIMPLELOCK_INITIALIZER;
129 
130 #define	PCI_CONF_LOCK(s)						\
131 do {									\
132 	(s) = splhigh();						\
133 	simple_lock(&pci_conf_slock);					\
134 } while (0)
135 
136 #define	PCI_CONF_UNLOCK(s)						\
137 do {									\
138 	simple_unlock(&pci_conf_slock);					\
139 	splx((s));							\
140 } while (0)
141 
142 #define	PCI_MODE1_ENABLE	0x80000000UL
143 #define	PCI_MODE1_ADDRESS_REG	0x0cf8
144 #define	PCI_MODE1_DATA_REG	0x0cfc
145 
146 #define	PCI_MODE2_ENABLE_REG	0x0cf8
147 #define	PCI_MODE2_FORWARD_REG	0x0cfa
148 
149 #define _m1tag(b, d, f) \
150 	(PCI_MODE1_ENABLE | ((b) << 16) | ((d) << 11) | ((f) << 8))
151 #define _qe(bus, dev, fcn, vend, prod) \
152 	{_m1tag(bus, dev, fcn), PCI_ID_CODE(vend, prod)}
153 struct {
154 	u_int32_t tag;
155 	pcireg_t id;
156 } pcim1_quirk_tbl[] = {
157 	_qe(0, 0, 0, PCI_VENDOR_COMPAQ, PCI_PRODUCT_COMPAQ_TRIFLEX1),
158 	/* XXX Triflex2 not tested */
159 	_qe(0, 0, 0, PCI_VENDOR_COMPAQ, PCI_PRODUCT_COMPAQ_TRIFLEX2),
160 	_qe(0, 0, 0, PCI_VENDOR_COMPAQ, PCI_PRODUCT_COMPAQ_TRIFLEX4),
161 	/* Triton needed for Connectix Virtual PC */
162 	_qe(0, 0, 0, PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82437FX),
163 	/* Connectix Virtual PC 5 has a 440BX */
164 	_qe(0, 0, 0, PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82443BX_NOAGP),
165 	/* Parallels Desktop for Mac */
166 	_qe(0, 2, 0, PCI_VENDOR_PARALLELS, PCI_PRODUCT_PARALLELS_VIDEO),
167 	_qe(0, 3, 0, PCI_VENDOR_PARALLELS, PCI_PRODUCT_PARALLELS_TOOLS),
168 	/* SIS 741 */
169 	_qe(0, 0, 0, PCI_VENDOR_SIS, PCI_PRODUCT_SIS_741),
170 	{0, 0xffffffff} /* patchable */
171 };
172 #undef _m1tag
173 #undef _id
174 #undef _qe
175 
176 /*
177  * PCI doesn't have any special needs; just use the generic versions
178  * of these functions.
179  */
180 struct x86_bus_dma_tag pci_bus_dma_tag = {
181 #if defined(_LP64) || defined(PAE)
182 	PCI32_DMA_BOUNCE_THRESHOLD,	/* bounce_thresh */
183 	ISA_DMA_BOUNCE_THRESHOLD,	/* bounce_alloclo */
184 	PCI32_DMA_BOUNCE_THRESHOLD,	/* bounce_allochi */
185 #else
186 	0,
187 	0,
188 	0,
189 #endif
190 	NULL,			/* _may_bounce */
191 	_bus_dmamap_create,
192 	_bus_dmamap_destroy,
193 	_bus_dmamap_load,
194 	_bus_dmamap_load_mbuf,
195 	_bus_dmamap_load_uio,
196 	_bus_dmamap_load_raw,
197 	_bus_dmamap_unload,
198 #if defined(_LP64) || defined(PAE)
199 	_bus_dmamap_sync,
200 #else
201 	NULL,
202 #endif
203 	_bus_dmamem_alloc,
204 	_bus_dmamem_free,
205 	_bus_dmamem_map,
206 	_bus_dmamem_unmap,
207 	_bus_dmamem_mmap,
208 };
209 
210 #ifdef _LP64
211 struct x86_bus_dma_tag pci_bus_dma64_tag = {
212 	0,
213 	0,
214 	0,
215 	NULL,			/* _may_bounce */
216 	_bus_dmamap_create,
217 	_bus_dmamap_destroy,
218 	_bus_dmamap_load,
219 	_bus_dmamap_load_mbuf,
220 	_bus_dmamap_load_uio,
221 	_bus_dmamap_load_raw,
222 	_bus_dmamap_unload,
223 	NULL,
224 	_bus_dmamem_alloc,
225 	_bus_dmamem_free,
226 	_bus_dmamem_map,
227 	_bus_dmamem_unmap,
228 	_bus_dmamem_mmap,
229 };
230 #endif
231 
232 void
233 pci_attach_hook(parent, self, pba)
234 	struct device *parent, *self;
235 	struct pcibus_attach_args *pba;
236 {
237 
238 	if (pba->pba_bus == 0)
239 		printf(": configuration mode %d", pci_mode);
240 #ifdef MPBIOS
241 	mpbios_pci_attach_hook(parent, self, pba);
242 #endif
243 #ifdef MPACPI
244 	mpacpi_pci_attach_hook(parent, self, pba);
245 #endif
246 }
247 
248 int
249 pci_bus_maxdevs(pc, busno)
250 	pci_chipset_tag_t pc;
251 	int busno;
252 {
253 
254 	/*
255 	 * Bus number is irrelevant.  If Configuration Mechanism 2 is in
256 	 * use, can only have devices 0-15 on any bus.  If Configuration
257 	 * Mechanism 1 is in use, can have devices 0-32 (i.e. the `normal'
258 	 * range).
259 	 */
260 	if (pci_mode == 2)
261 		return (16);
262 	else
263 		return (32);
264 }
265 
266 pcitag_t
267 pci_make_tag(pc, bus, device, function)
268 	pci_chipset_tag_t pc;
269 	int bus, device, function;
270 {
271 	pcitag_t tag;
272 
273 #ifndef PCI_CONF_MODE
274 	switch (pci_mode) {
275 	case 1:
276 		goto mode1;
277 	case 2:
278 		goto mode2;
279 	default:
280 		panic("pci_make_tag: mode not configured");
281 	}
282 #endif
283 
284 #if !defined(PCI_CONF_MODE) || (PCI_CONF_MODE == 1)
285 #ifndef PCI_CONF_MODE
286 mode1:
287 #endif
288 	if (bus >= 256 || device >= 32 || function >= 8)
289 		panic("pci_make_tag: bad request");
290 
291 	tag.mode1 = PCI_MODE1_ENABLE |
292 		    (bus << 16) | (device << 11) | (function << 8);
293 	return tag;
294 #endif
295 
296 #if !defined(PCI_CONF_MODE) || (PCI_CONF_MODE == 2)
297 #ifndef PCI_CONF_MODE
298 mode2:
299 #endif
300 	if (bus >= 256 || device >= 16 || function >= 8)
301 		panic("pci_make_tag: bad request");
302 
303 	tag.mode2.port = 0xc000 | (device << 8);
304 	tag.mode2.enable = 0xf0 | (function << 1);
305 	tag.mode2.forward = bus;
306 	return tag;
307 #endif
308 }
309 
310 void
311 pci_decompose_tag(pc, tag, bp, dp, fp)
312 	pci_chipset_tag_t pc;
313 	pcitag_t tag;
314 	int *bp, *dp, *fp;
315 {
316 
317 #ifndef PCI_CONF_MODE
318 	switch (pci_mode) {
319 	case 1:
320 		goto mode1;
321 	case 2:
322 		goto mode2;
323 	default:
324 		panic("pci_decompose_tag: mode not configured");
325 	}
326 #endif
327 
328 #if !defined(PCI_CONF_MODE) || (PCI_CONF_MODE == 1)
329 #ifndef PCI_CONF_MODE
330 mode1:
331 #endif
332 	if (bp != NULL)
333 		*bp = (tag.mode1 >> 16) & 0xff;
334 	if (dp != NULL)
335 		*dp = (tag.mode1 >> 11) & 0x1f;
336 	if (fp != NULL)
337 		*fp = (tag.mode1 >> 8) & 0x7;
338 	return;
339 #endif
340 
341 #if !defined(PCI_CONF_MODE) || (PCI_CONF_MODE == 2)
342 #ifndef PCI_CONF_MODE
343 mode2:
344 #endif
345 	if (bp != NULL)
346 		*bp = tag.mode2.forward & 0xff;
347 	if (dp != NULL)
348 		*dp = (tag.mode2.port >> 8) & 0xf;
349 	if (fp != NULL)
350 		*fp = (tag.mode2.enable >> 1) & 0x7;
351 #endif
352 }
353 
354 pcireg_t
355 pci_conf_read(pc, tag, reg)
356 	pci_chipset_tag_t pc;
357 	pcitag_t tag;
358 	int reg;
359 {
360 	pcireg_t data;
361 	int s;
362 
363 #ifndef PCI_CONF_MODE
364 	switch (pci_mode) {
365 	case 1:
366 		goto mode1;
367 	case 2:
368 		goto mode2;
369 	default:
370 		panic("pci_conf_read: mode not configured");
371 	}
372 #endif
373 
374 #if !defined(PCI_CONF_MODE) || (PCI_CONF_MODE == 1)
375 #ifndef PCI_CONF_MODE
376 mode1:
377 #endif
378 	PCI_CONF_LOCK(s);
379 	outl(PCI_MODE1_ADDRESS_REG, tag.mode1 | reg);
380 	data = inl(PCI_MODE1_DATA_REG);
381 	outl(PCI_MODE1_ADDRESS_REG, 0);
382 	PCI_CONF_UNLOCK(s);
383 	return data;
384 #endif
385 
386 #if !defined(PCI_CONF_MODE) || (PCI_CONF_MODE == 2)
387 #ifndef PCI_CONF_MODE
388 mode2:
389 #endif
390 	PCI_CONF_LOCK(s);
391 	outb(PCI_MODE2_ENABLE_REG, tag.mode2.enable);
392 	outb(PCI_MODE2_FORWARD_REG, tag.mode2.forward);
393 	data = inl(tag.mode2.port | reg);
394 	outb(PCI_MODE2_ENABLE_REG, 0);
395 	PCI_CONF_UNLOCK(s);
396 	return data;
397 #endif
398 }
399 
400 void
401 pci_conf_write(pc, tag, reg, data)
402 	pci_chipset_tag_t pc;
403 	pcitag_t tag;
404 	int reg;
405 	pcireg_t data;
406 {
407 	int s;
408 
409 #ifndef PCI_CONF_MODE
410 	switch (pci_mode) {
411 	case 1:
412 		goto mode1;
413 	case 2:
414 		goto mode2;
415 	default:
416 		panic("pci_conf_write: mode not configured");
417 	}
418 #endif
419 
420 #if !defined(PCI_CONF_MODE) || (PCI_CONF_MODE == 1)
421 #ifndef PCI_CONF_MODE
422 mode1:
423 #endif
424 	PCI_CONF_LOCK(s);
425 	outl(PCI_MODE1_ADDRESS_REG, tag.mode1 | reg);
426 	outl(PCI_MODE1_DATA_REG, data);
427 	outl(PCI_MODE1_ADDRESS_REG, 0);
428 	PCI_CONF_UNLOCK(s);
429 	return;
430 #endif
431 
432 #if !defined(PCI_CONF_MODE) || (PCI_CONF_MODE == 2)
433 #ifndef PCI_CONF_MODE
434 mode2:
435 #endif
436 	PCI_CONF_LOCK(s);
437 	outb(PCI_MODE2_ENABLE_REG, tag.mode2.enable);
438 	outb(PCI_MODE2_FORWARD_REG, tag.mode2.forward);
439 	outl(tag.mode2.port | reg, data);
440 	outb(PCI_MODE2_ENABLE_REG, 0);
441 	PCI_CONF_UNLOCK(s);
442 #endif
443 }
444 
445 int
446 pci_mode_detect()
447 {
448 
449 #ifdef PCI_CONF_MODE
450 #if (PCI_CONF_MODE == 1) || (PCI_CONF_MODE == 2)
451 	return (pci_mode = PCI_CONF_MODE);
452 #else
453 #error Invalid PCI configuration mode.
454 #endif
455 #else
456 	u_int32_t sav, val;
457 	int i;
458 	pcireg_t idreg;
459 
460 	if (pci_mode != -1)
461 		return pci_mode;
462 
463 	/*
464 	 * We try to divine which configuration mode the host bridge wants.
465 	 */
466 
467 	sav = inl(PCI_MODE1_ADDRESS_REG);
468 
469 	pci_mode = 1; /* assume this for now */
470 	/*
471 	 * catch some known buggy implementations of mode 1
472 	 */
473 	for (i = 0; i < sizeof(pcim1_quirk_tbl) / sizeof(pcim1_quirk_tbl[0]);
474 	     i++) {
475 		pcitag_t t;
476 
477 		if (!pcim1_quirk_tbl[i].tag)
478 			break;
479 		t.mode1 = pcim1_quirk_tbl[i].tag;
480 		idreg = pci_conf_read(0, t, PCI_ID_REG); /* needs "pci_mode" */
481 		if (idreg == pcim1_quirk_tbl[i].id) {
482 #ifdef DEBUG
483 			printf("known mode 1 PCI chipset (%08x)\n",
484 			       idreg);
485 #endif
486 			return (pci_mode);
487 		}
488 	}
489 
490 	/*
491 	 * Strong check for standard compliant mode 1:
492 	 * 1. bit 31 ("enable") can be set
493 	 * 2. byte/word access does not affect register
494 	 */
495 	outl(PCI_MODE1_ADDRESS_REG, PCI_MODE1_ENABLE);
496 	outb(PCI_MODE1_ADDRESS_REG + 3, 0);
497 	outw(PCI_MODE1_ADDRESS_REG + 2, 0);
498 	val = inl(PCI_MODE1_ADDRESS_REG);
499 	if ((val & 0x80fffffc) != PCI_MODE1_ENABLE) {
500 #ifdef DEBUG
501 		printf("pci_mode_detect: mode 1 enable failed (%x)\n",
502 		       val);
503 #endif
504 		goto not1;
505 	}
506 	outl(PCI_MODE1_ADDRESS_REG, 0);
507 	val = inl(PCI_MODE1_ADDRESS_REG);
508 	if ((val & 0x80fffffc) != 0)
509 		goto not1;
510 	return (pci_mode);
511 not1:
512 	outl(PCI_MODE1_ADDRESS_REG, sav);
513 
514 	/*
515 	 * This mode 2 check is quite weak (and known to give false
516 	 * positives on some Compaq machines).
517 	 * However, this doesn't matter, because this is the
518 	 * last test, and simply no PCI devices will be found if
519 	 * this happens.
520 	 */
521 	outb(PCI_MODE2_ENABLE_REG, 0);
522 	outb(PCI_MODE2_FORWARD_REG, 0);
523 	if (inb(PCI_MODE2_ENABLE_REG) != 0 ||
524 	    inb(PCI_MODE2_FORWARD_REG) != 0)
525 		goto not2;
526 	return (pci_mode = 2);
527 not2:
528 
529 	return (pci_mode = 0);
530 #endif
531 }
532 
533 /*
534  * Determine which flags should be passed to the primary PCI bus's
535  * autoconfiguration node.  We use this to detect broken chipsets
536  * which cannot safely use memory-mapped device access.
537  */
538 int
539 pci_bus_flags()
540 {
541 	int rval = PCI_FLAGS_IO_ENABLED | PCI_FLAGS_MEM_ENABLED |
542 	    PCI_FLAGS_MRL_OKAY | PCI_FLAGS_MRM_OKAY | PCI_FLAGS_MWI_OKAY;
543 	int device, maxndevs;
544 	pcitag_t tag;
545 	pcireg_t id;
546 
547 	maxndevs = pci_bus_maxdevs(NULL, 0);
548 
549 	for (device = 0; device < maxndevs; device++) {
550 		tag = pci_make_tag(NULL, 0, device, 0);
551 		id = pci_conf_read(NULL, tag, PCI_ID_REG);
552 
553 		/* Invalid vendor ID value? */
554 		if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
555 			continue;
556 		/* XXX Not invalid, but we've done this ~forever. */
557 		if (PCI_VENDOR(id) == 0)
558 			continue;
559 
560 		switch (PCI_VENDOR(id)) {
561 		case PCI_VENDOR_SIS:
562 			switch (PCI_PRODUCT(id)) {
563 			case PCI_PRODUCT_SIS_85C496:
564 				goto disable_mem;
565 			}
566 			break;
567 		}
568 	}
569 
570 	return (rval);
571 
572  disable_mem:
573 	printf("Warning: broken PCI-Host bridge detected; "
574 	    "disabling memory-mapped access\n");
575 	rval &= ~(PCI_FLAGS_MEM_ENABLED|PCI_FLAGS_MRL_OKAY|PCI_FLAGS_MRM_OKAY|
576 	    PCI_FLAGS_MWI_OKAY);
577 	return (rval);
578 }
579 
580 void
581 pci_device_foreach(pci_chipset_tag_t pc, int maxbus,
582 	void (*func)(pci_chipset_tag_t, pcitag_t, void *), void *context)
583 {
584 	pci_device_foreach_min(pc, 0, maxbus, func, context);
585 }
586 
587 void
588 pci_device_foreach_min(pci_chipset_tag_t pc, int minbus, int maxbus,
589 	void (*func)(pci_chipset_tag_t, pcitag_t, void *), void *context)
590 {
591 	const struct pci_quirkdata *qd;
592 	int bus, device, function, maxdevs, nfuncs;
593 	pcireg_t id, bhlcr;
594 	pcitag_t tag;
595 
596 	for (bus = minbus; bus <= maxbus; bus++) {
597 		maxdevs = pci_bus_maxdevs(pc, bus);
598 		for (device = 0; device < maxdevs; device++) {
599 			tag = pci_make_tag(pc, bus, device, 0);
600 			id = pci_conf_read(pc, tag, PCI_ID_REG);
601 
602 			/* Invalid vendor ID value? */
603 			if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
604 				continue;
605 			/* XXX Not invalid, but we've done this ~forever. */
606 			if (PCI_VENDOR(id) == 0)
607 				continue;
608 
609 			qd = pci_lookup_quirkdata(PCI_VENDOR(id),
610 				PCI_PRODUCT(id));
611 
612 			bhlcr = pci_conf_read(pc, tag, PCI_BHLC_REG);
613 			if (PCI_HDRTYPE_MULTIFN(bhlcr) ||
614 			     (qd != NULL &&
615 		  	     (qd->quirks & PCI_QUIRK_MULTIFUNCTION) != 0))
616 				nfuncs = 8;
617 			else
618 				nfuncs = 1;
619 
620 			for (function = 0; function < nfuncs; function++) {
621 				tag = pci_make_tag(pc, bus, device, function);
622 				id = pci_conf_read(pc, tag, PCI_ID_REG);
623 
624 				/* Invalid vendor ID value? */
625 				if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
626 					continue;
627 				/*
628 				 * XXX Not invalid, but we've done this
629 				 * ~forever.
630 				 */
631 				if (PCI_VENDOR(id) == 0)
632 					continue;
633 				(*func)(pc, tag, context);
634 			}
635 		}
636 	}
637 }
638 
639 void
640 pci_bridge_foreach(pci_chipset_tag_t pc, int minbus, int maxbus,
641 	void (*func)(pci_chipset_tag_t, pcitag_t, void *), void *ctx)
642 {
643 	struct pci_bridge_hook_arg bridge_hook;
644 
645 	bridge_hook.func = func;
646 	bridge_hook.arg = ctx;
647 
648 	pci_device_foreach_min(pc, minbus, maxbus, pci_bridge_hook,
649 		&bridge_hook);
650 }
651 
652 static void
653 pci_bridge_hook(pci_chipset_tag_t pc, pcitag_t tag, void *ctx)
654 {
655 	struct pci_bridge_hook_arg *bridge_hook = (void *)ctx;
656 	pcireg_t reg;
657 
658 	reg = pci_conf_read(pc, tag, PCI_CLASS_REG);
659 	if (PCI_CLASS(reg) == PCI_CLASS_BRIDGE &&
660  	     (PCI_SUBCLASS(reg) == PCI_SUBCLASS_BRIDGE_PCI ||
661 		PCI_SUBCLASS(reg) == PCI_SUBCLASS_BRIDGE_CARDBUS)) {
662 		(*bridge_hook->func)(pc, tag, bridge_hook->arg);
663 	}
664 }
665