xref: /netbsd-src/sys/dev/pci/pciconf.c (revision 1b9578b8c2c1f848eeb16dabbfd7d1f0d9fdefbd)
1 /*	$NetBSD: pciconf.c,v 1.32 2010/12/11 18:21:14 matt Exp $	*/
2 
3 /*
4  * Copyright 2001 Wasabi Systems, Inc.
5  * All rights reserved.
6  *
7  * Written by Allen Briggs for Wasabi Systems, Inc.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *      This product includes software developed for the NetBSD Project by
20  *      Wasabi Systems, Inc.
21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22  *    or promote products derived from this software without specific prior
23  *    written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35  * POSSIBILITY OF SUCH DAMAGE.
36  */
37 /*
38  * Derived in part from code from PMON/2000 (http://pmon.groupbsd.org/).
39  */
40 
41 /*
42  * To do:
43  *    - Perform all data structure allocation dynamically, don't have
44  *	statically-sized arrays ("oops, you lose because you have too
45  *	many slots filled!")
46  *    - Do this in 2 passes, with an MD hook to control the behavior:
47  *		(1) Configure the bus (possibly including expansion
48  *		    ROMs.
49  *		(2) Another pass to disable expansion ROMs if they're
50  *		    mapped (since you're not supposed to leave them
51  *		    mapped when you're not using them).
52  *	This would facilitate MD code executing the expansion ROMs
53  *	if necessary (possibly with an x86 emulator) to configure
54  *	devices (e.g. VGA cards).
55  *    - Deal with "anything can be hot-plugged" -- i.e., carry configuration
56  *	information around & be able to reconfigure on the fly
57  *    - Deal with segments (See IA64 System Abstraction Layer)
58  *    - Deal with subtractive bridges (& non-spec positive/subtractive decode)
59  *    - Deal with ISA/VGA/VGA palette snooping
60  *    - Deal with device capabilities on bridges
61  *    - Worry about changing a bridge to/from transparency
62  * From thorpej (05/25/01)
63  *    - Try to handle devices that are already configured (perhaps using that
64  *      as a hint to where we put other devices)
65  */
66 
67 #include <sys/cdefs.h>
68 __KERNEL_RCSID(0, "$NetBSD: pciconf.c,v 1.32 2010/12/11 18:21:14 matt Exp $");
69 
70 #include "opt_pci.h"
71 
72 #include <sys/param.h>
73 #include <sys/extent.h>
74 #include <sys/queue.h>
75 #include <sys/systm.h>
76 #include <sys/malloc.h>
77 #include <sys/kmem.h>
78 
79 #include <dev/pci/pcivar.h>
80 #include <dev/pci/pciconf.h>
81 #include <dev/pci/pcidevs.h>
82 #include <dev/pci/pccbbreg.h>
83 
84 int pci_conf_debug = 0;
85 
86 #if !defined(MIN)
87 #define	MIN(a,b) (((a)<(b))?(a):(b))
88 #define	MAX(a,b) (((a)>(b))?(a):(b))
89 #endif
90 
91 /* per-bus constants. */
92 #define MAX_CONF_DEV	32			/* Arbitrary */
93 #define MAX_CONF_MEM	(3 * MAX_CONF_DEV)	/* Avg. 3 per device -- Arb. */
94 #define MAX_CONF_IO	(3 * MAX_CONF_DEV)	/* Avg. 1 per device -- Arb. */
95 
96 struct _s_pciconf_bus_t;			/* Forward declaration */
97 
98 typedef struct _s_pciconf_dev_t {
99 	int		ipin;
100 	int		iline;
101 	int		min_gnt;
102 	int		max_lat;
103 	int		enable;
104 	pcitag_t	tag;
105 	pci_chipset_tag_t	pc;
106 	struct _s_pciconf_bus_t	*ppb;		/* I am really a bridge */
107 } pciconf_dev_t;
108 
109 typedef struct _s_pciconf_win_t {
110 	pciconf_dev_t	*dev;
111 	int		reg;			/* 0 for busses */
112 	int		align;
113 	int		prefetch;
114 	u_int64_t	size;
115 	u_int64_t	address;
116 } pciconf_win_t;
117 
118 typedef struct _s_pciconf_bus_t {
119 	int		busno;
120 	int		next_busno;
121 	int		last_busno;
122 	int		max_mingnt;
123 	int		min_maxlat;
124 	int		cacheline_size;
125 	int		prefetch;
126 	int		fast_b2b;
127 	int		freq_66;
128 	int		def_ltim;
129 	int		max_ltim;
130 	int		bandwidth_used;
131 	int		swiz;
132 	int		io_32bit;
133 	int		pmem_64bit;
134 
135 	int		ndevs;
136 	pciconf_dev_t	device[MAX_CONF_DEV];
137 
138 	/* These should be sorted in order of decreasing size */
139 	int		nmemwin;
140 	pciconf_win_t	pcimemwin[MAX_CONF_MEM];
141 	int		niowin;
142 	pciconf_win_t	pciiowin[MAX_CONF_IO];
143 
144 	bus_size_t	io_total;
145 	bus_size_t	mem_total;
146 	bus_size_t	pmem_total;
147 
148 	struct extent	*ioext;
149 	struct extent	*memext;
150 	struct extent	*pmemext;
151 
152 	pci_chipset_tag_t	pc;
153 	struct _s_pciconf_bus_t *parent_bus;
154 } pciconf_bus_t;
155 
156 static int	probe_bus(pciconf_bus_t *);
157 static void	alloc_busno(pciconf_bus_t *, pciconf_bus_t *);
158 static void	set_busreg(pci_chipset_tag_t, pcitag_t, int, int, int);
159 static int	pci_do_device_query(pciconf_bus_t *, pcitag_t, int, int, int);
160 static int	setup_iowins(pciconf_bus_t *);
161 static int	setup_memwins(pciconf_bus_t *);
162 static int	configure_bridge(pciconf_dev_t *);
163 static int	configure_bus(pciconf_bus_t *);
164 static u_int64_t	pci_allocate_range(struct extent *, u_int64_t, int);
165 static pciconf_win_t	*get_io_desc(pciconf_bus_t *, bus_size_t);
166 static pciconf_win_t	*get_mem_desc(pciconf_bus_t *, bus_size_t);
167 static pciconf_bus_t	*query_bus(pciconf_bus_t *, pciconf_dev_t *, int);
168 
169 static void	print_tag(pci_chipset_tag_t, pcitag_t);
170 
171 static void
172 print_tag(pci_chipset_tag_t pc, pcitag_t tag)
173 {
174 	int	bus, dev, func;
175 
176 	pci_decompose_tag(pc, tag, &bus, &dev, &func);
177 	printf("PCI: bus %d, device %d, function %d: ", bus, dev, func);
178 }
179 
180 /************************************************************************/
181 /************************************************************************/
182 /***********************   Bus probing routines   ***********************/
183 /************************************************************************/
184 /************************************************************************/
185 static pciconf_win_t *
186 get_io_desc(pciconf_bus_t *pb, bus_size_t size)
187 {
188 	int	i, n;
189 
190 	n = pb->niowin;
191 	for (i=n; i > 0 && size > pb->pciiowin[i-1].size; i--)
192 		pb->pciiowin[i] = pb->pciiowin[i-1]; /* struct copy */
193 	return &pb->pciiowin[i];
194 }
195 
196 static pciconf_win_t *
197 get_mem_desc(pciconf_bus_t *pb, bus_size_t size)
198 {
199 	int	i, n;
200 
201 	n = pb->nmemwin;
202 	for (i=n; i > 0 && size > pb->pcimemwin[i-1].size; i--)
203 		pb->pcimemwin[i] = pb->pcimemwin[i-1]; /* struct copy */
204 	return &pb->pcimemwin[i];
205 }
206 
207 /*
208  * Set up bus common stuff, then loop over devices & functions.
209  * If we find something, call pci_do_device_query()).
210  */
211 static int
212 probe_bus(pciconf_bus_t *pb)
213 {
214 	int device, maxdevs;
215 #ifdef __PCI_BUS_DEVORDER
216 	char devs[32];
217 	int  i;
218 #endif
219 
220 	maxdevs = pci_bus_maxdevs(pb->pc, pb->busno);
221 	pb->ndevs = 0;
222 	pb->niowin = 0;
223 	pb->nmemwin = 0;
224 	pb->freq_66 = 1;
225 #ifdef PCICONF_NO_FAST_B2B
226 	pb->fast_b2b = 0;
227 #else
228 	pb->fast_b2b = 1;
229 #endif
230 	pb->prefetch = 1;
231 	pb->max_mingnt = 0;	/* we are looking for the maximum */
232 	pb->min_maxlat = 0x100;	/* we are looking for the minimum */
233 	pb->bandwidth_used = 0;
234 
235 #ifdef __PCI_BUS_DEVORDER
236 	pci_bus_devorder(pb->pc, pb->busno, devs);
237 	for (i = 0; (device = devs[i]) < 32 && device >= 0; i++) {
238 #else
239 	for (device = 0; device < maxdevs; device++) {
240 #endif
241 		pcitag_t tag;
242 		pcireg_t id, bhlcr;
243 		int function, nfunction;
244 		int confmode;
245 
246 		tag = pci_make_tag(pb->pc, pb->busno, device, 0);
247 		if (pci_conf_debug) {
248 			print_tag(pb->pc, tag);
249 		}
250 		id = pci_conf_read(pb->pc, tag, PCI_ID_REG);
251 
252 		if (pci_conf_debug) {
253 			printf("id=%x: Vendor=%x, Product=%x\n",
254 			    id, PCI_VENDOR(id),PCI_PRODUCT(id));
255 		}
256 		/* Invalid vendor ID value? */
257 		if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
258 			continue;
259 
260 		bhlcr = pci_conf_read(pb->pc, tag, PCI_BHLC_REG);
261 		nfunction = PCI_HDRTYPE_MULTIFN(bhlcr) ? 8 : 1;
262 		for (function = 0 ; function < nfunction ; function++) {
263 			tag = pci_make_tag(pb->pc, pb->busno, device, function);
264 			id = pci_conf_read(pb->pc, tag, PCI_ID_REG);
265 			if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
266 				continue;
267 			if (pb->ndevs+1 < MAX_CONF_DEV) {
268 				if (pci_conf_debug) {
269 					print_tag(pb->pc, tag);
270 					printf("Found dev 0x%04x 0x%04x -- "
271 					    "really probing.\n",
272 					PCI_VENDOR(id), PCI_PRODUCT(id));
273 				}
274 #ifdef __HAVE_PCI_CONF_HOOK
275 				confmode = pci_conf_hook(pb->pc, pb->busno,
276 				    device, function, id);
277 				if (confmode == 0)
278 					continue;
279 #else
280 				/*
281 				 * Don't enable expansion ROMS -- some cards
282 				 * share address decoders between the EXPROM
283 				 * and PCI memory space, and enabling the ROM
284 				 * when not needed will cause all sorts of
285 				 * lossage.
286 				 */
287 				confmode = PCI_CONF_DEFAULT;
288 #endif
289 				if (pci_do_device_query(pb, tag, device,
290 				    function, confmode))
291 					return -1;
292 				pb->ndevs++;
293 			}
294 		}
295 	}
296 	return 0;
297 }
298 
299 static void
300 alloc_busno(pciconf_bus_t *parent, pciconf_bus_t *pb)
301 {
302 	pb->busno = parent->next_busno;
303 	pb->next_busno = pb->busno + 1;
304 }
305 
306 static void
307 set_busreg(pci_chipset_tag_t pc, pcitag_t tag, int prim, int sec, int sub)
308 {
309 	pcireg_t	busreg;
310 
311 	busreg  =  prim << PCI_BRIDGE_BUS_PRIMARY_SHIFT;
312 	busreg |=   sec << PCI_BRIDGE_BUS_SECONDARY_SHIFT;
313 	busreg |=   sub << PCI_BRIDGE_BUS_SUBORDINATE_SHIFT;
314 	pci_conf_write(pc, tag, PCI_BRIDGE_BUS_REG, busreg);
315 }
316 
317 static pciconf_bus_t *
318 query_bus(pciconf_bus_t *parent, pciconf_dev_t *pd, int dev)
319 {
320 	pciconf_bus_t	*pb;
321 	pcireg_t	io, pmem;
322 	pciconf_win_t	*pi, *pm;
323 
324 	pb = kmem_zalloc(sizeof (pciconf_bus_t), KM_NOSLEEP);
325 	if (!pb)
326 		panic("Unable to allocate memory for PCI configuration.");
327 
328 	pb->cacheline_size = parent->cacheline_size;
329 	pb->parent_bus = parent;
330 	alloc_busno(parent, pb);
331 
332 	set_busreg(parent->pc, pd->tag, parent->busno, pb->busno, 0xff);
333 
334 	pb->swiz = parent->swiz + dev;
335 
336 	pb->ioext = NULL;
337 	pb->memext = NULL;
338 	pb->pmemext = NULL;
339 	pb->pc = parent->pc;
340 	pb->io_total = pb->mem_total = pb->pmem_total = 0;
341 
342 	pb->io_32bit = 0;
343 	if (parent->io_32bit) {
344 		io = pci_conf_read(parent->pc, pd->tag, PCI_BRIDGE_STATIO_REG);
345 		if (PCI_BRIDGE_IO_32BITS(io)) {
346 			pb->io_32bit = 1;
347 		}
348 	}
349 
350 	pb->pmem_64bit = 0;
351 	if (parent->pmem_64bit) {
352 		pmem = pci_conf_read(parent->pc, pd->tag,
353 		    PCI_BRIDGE_PREFETCHMEM_REG);
354 		if (PCI_BRIDGE_PREFETCHMEM_64BITS(pmem)) {
355 			pb->pmem_64bit = 1;
356 		}
357 	}
358 
359 	if (probe_bus(pb)) {
360 		printf("Failed to probe bus %d\n", pb->busno);
361 		goto err;
362 	}
363 
364 	/* We have found all subordinate busses now, reprogram busreg. */
365 	pb->last_busno = pb->next_busno-1;
366 	parent->next_busno = pb->next_busno;
367 	set_busreg(parent->pc, pd->tag, parent->busno, pb->busno,
368 		   pb->last_busno);
369 	if (pci_conf_debug)
370 		printf("PCI bus bridge (parent %d) covers busses %d-%d\n",
371 			parent->busno, pb->busno, pb->last_busno);
372 
373 	if (pb->io_total > 0) {
374 		if (parent->niowin >= MAX_CONF_IO) {
375 			printf("pciconf: too many I/O windows\n");
376 			goto err;
377 		}
378 		pb->io_total |= 0xfff;	/* Round up */
379 		pi = get_io_desc(parent, pb->io_total);
380 		pi->dev = pd;
381 		pi->reg = 0;
382 		pi->size = pb->io_total;
383 		pi->align = 0x1000;	/* 4K alignment */
384 		pi->prefetch = 0;
385 		parent->niowin++;
386 		parent->io_total += pb->io_total;
387 	}
388 
389 	if (pb->mem_total > 0) {
390 		if (parent->nmemwin >= MAX_CONF_MEM) {
391 			printf("pciconf: too many MEM windows\n");
392 			goto err;
393 		}
394 		pb->mem_total |= 0xfffff;	/* Round up */
395 		pm = get_mem_desc(parent, pb->mem_total);
396 		pm->dev = pd;
397 		pm->reg = 0;
398 		pm->size = pb->mem_total;
399 		pm->align = 0x100000;	/* 1M alignment */
400 		pm->prefetch = 0;
401 		parent->nmemwin++;
402 		parent->mem_total += pb->mem_total;
403 	}
404 
405 	if (pb->pmem_total > 0) {
406 		if (parent->nmemwin >= MAX_CONF_MEM) {
407 			printf("pciconf: too many MEM windows\n");
408 			goto err;
409 		}
410 		pb->pmem_total |= 0xfffff;	/* Round up */
411 		pm = get_mem_desc(parent, pb->pmem_total);
412 		pm->dev = pd;
413 		pm->reg = 0;
414 		pm->size = pb->pmem_total;
415 		pm->align = 0x100000;		/* 1M alignment */
416 		pm->prefetch = 1;
417 		parent->nmemwin++;
418 		parent->pmem_total += pb->pmem_total;
419 	}
420 
421 	return pb;
422 err:
423 	kmem_free(pb, sizeof(*pb));
424 	return NULL;
425 }
426 
427 static int
428 pci_do_device_query(pciconf_bus_t *pb, pcitag_t tag, int dev, int func, int mode)
429 {
430 	pciconf_dev_t	*pd;
431 	pciconf_win_t	*pi, *pm;
432 	pcireg_t	class, cmd, icr, bhlc, bar, mask, bar64, mask64, busreg;
433 	u_int64_t	size;
434 	int		br, width, reg_start, reg_end;
435 
436 	pd = &pb->device[pb->ndevs];
437 	pd->pc = pb->pc;
438 	pd->tag = tag;
439 	pd->ppb = NULL;
440 	pd->enable = mode;
441 
442 	class = pci_conf_read(pb->pc, tag, PCI_CLASS_REG);
443 
444 	cmd = pci_conf_read(pb->pc, tag, PCI_COMMAND_STATUS_REG);
445 	bhlc = pci_conf_read(pb->pc, tag, PCI_BHLC_REG);
446 
447 	if (PCI_CLASS(class) != PCI_CLASS_BRIDGE
448 	    && PCI_HDRTYPE_TYPE(bhlc) != PCI_HDRTYPE_PPB) {
449 		cmd &= ~(PCI_COMMAND_MASTER_ENABLE |
450 		    PCI_COMMAND_IO_ENABLE | PCI_COMMAND_MEM_ENABLE);
451 		pci_conf_write(pb->pc, tag, PCI_COMMAND_STATUS_REG, cmd);
452 	} else if (pci_conf_debug) {
453 		print_tag(pb->pc, tag);
454 		printf("device is a bridge; not clearing enables\n");
455 	}
456 
457 	if ((cmd & PCI_STATUS_BACKTOBACK_SUPPORT) == 0)
458 		pb->fast_b2b = 0;
459 
460 	if ((cmd & PCI_STATUS_66MHZ_SUPPORT) == 0)
461 		pb->freq_66 = 0;
462 
463 	switch (PCI_HDRTYPE_TYPE(bhlc)) {
464 	case PCI_HDRTYPE_DEVICE:
465 		reg_start = PCI_MAPREG_START;
466 		reg_end = PCI_MAPREG_END;
467 		break;
468 	case PCI_HDRTYPE_PPB:
469 		pd->ppb = query_bus(pb, pd, dev);
470 		if (pd->ppb == NULL)
471 			return -1;
472 		return 0;
473 	case PCI_HDRTYPE_PCB:
474 		reg_start = PCI_MAPREG_START;
475 		reg_end = PCI_MAPREG_PCB_END;
476 
477 		busreg = pci_conf_read(pb->pc, tag, PCI_BUSNUM);
478 		busreg  =  (busreg & 0xff000000) |
479 		    pb->busno << PCI_BRIDGE_BUS_PRIMARY_SHIFT |
480 		    pb->next_busno << PCI_BRIDGE_BUS_SECONDARY_SHIFT |
481 		    pb->next_busno << PCI_BRIDGE_BUS_SUBORDINATE_SHIFT;
482 		pci_conf_write(pb->pc, tag, PCI_BUSNUM, busreg);
483 
484 		pb->next_busno++;
485 		break;
486 	default:
487 		return -1;
488 	}
489 
490 	icr = pci_conf_read(pb->pc, tag, PCI_INTERRUPT_REG);
491 	pd->ipin = PCI_INTERRUPT_PIN(icr);
492 	pd->iline = PCI_INTERRUPT_LINE(icr);
493 	pd->min_gnt = PCI_MIN_GNT(icr);
494 	pd->max_lat = PCI_MAX_LAT(icr);
495 	if (pd->iline || pd->ipin) {
496 		pci_conf_interrupt(pb->pc, pb->busno, dev, pd->ipin, pb->swiz,
497 		    &pd->iline);
498 		icr &= ~(PCI_INTERRUPT_LINE_MASK << PCI_INTERRUPT_LINE_SHIFT);
499 		icr |= (pd->iline << PCI_INTERRUPT_LINE_SHIFT);
500 		pci_conf_write(pb->pc, tag, PCI_INTERRUPT_REG, icr);
501 	}
502 
503 	if (pd->min_gnt != 0 || pd->max_lat != 0) {
504 		if (pd->min_gnt != 0 && pd->min_gnt > pb->max_mingnt)
505 			pb->max_mingnt = pd->min_gnt;
506 
507 		if (pd->max_lat != 0 && pd->max_lat < pb->min_maxlat)
508 			pb->min_maxlat = pd->max_lat;
509 
510 		pb->bandwidth_used += pd->min_gnt * 4000000 /
511 				(pd->min_gnt + pd->max_lat);
512 	}
513 
514 	width = 4;
515 	for (br = reg_start; br < reg_end; br += width) {
516 #if 0
517 /* XXX Should only ignore if IDE not in legacy mode? */
518 		if (PCI_CLASS(class) == PCI_CLASS_MASS_STORAGE &&
519 		    PCI_SUBCLASS(class) == PCI_SUBCLASS_MASS_STORAGE_IDE) {
520 			break;
521 		}
522 #endif
523 		bar = pci_conf_read(pb->pc, tag, br);
524 		pci_conf_write(pb->pc, tag, br, 0xffffffff);
525 		mask = pci_conf_read(pb->pc, tag, br);
526 		pci_conf_write(pb->pc, tag, br, bar);
527 		width = 4;
528 
529 		if (   (mode & PCI_CONF_MAP_IO)
530 		    && (PCI_MAPREG_TYPE(mask) == PCI_MAPREG_TYPE_IO)) {
531 			/*
532 			 * Upper 16 bits must be one.  Devices may hardwire
533 			 * them to zero, though, per PCI 2.2, 6.2.5.1, p 203.
534 			 */
535 			mask |= 0xffff0000;
536 
537 			size = PCI_MAPREG_IO_SIZE(mask);
538 			if (size == 0) {
539 				if (pci_conf_debug) {
540 					print_tag(pb->pc, tag);
541 					printf("I/O BAR 0x%x is void\n", br);
542 				}
543 				continue;
544 			}
545 
546 			if (pb->niowin >= MAX_CONF_IO) {
547 				printf("pciconf: too many I/O windows\n");
548 				return -1;
549 			}
550 
551 			pi = get_io_desc(pb, size);
552 			pi->dev = pd;
553 			pi->reg = br;
554 			pi->size = (u_int64_t) size;
555 			pi->align = 4;
556 			pi->prefetch = 0;
557 			if (pci_conf_debug) {
558 				print_tag(pb->pc, tag);
559 				printf("Register 0x%x, I/O size %" PRIu64 "\n",
560 				    br, pi->size);
561 			}
562 			pb->niowin++;
563 			pb->io_total += size;
564 		} else if ((mode & PCI_CONF_MAP_MEM)
565 			   && (PCI_MAPREG_TYPE(mask) == PCI_MAPREG_TYPE_MEM)) {
566 			switch (PCI_MAPREG_MEM_TYPE(mask)) {
567 			case PCI_MAPREG_MEM_TYPE_32BIT:
568 			case PCI_MAPREG_MEM_TYPE_32BIT_1M:
569 				size = (u_int64_t) PCI_MAPREG_MEM_SIZE(mask);
570 				break;
571 			case PCI_MAPREG_MEM_TYPE_64BIT:
572 				bar64 = pci_conf_read(pb->pc, tag, br + 4);
573 				pci_conf_write(pb->pc, tag, br + 4, 0xffffffff);
574 				mask64 = pci_conf_read(pb->pc, tag, br + 4);
575 				pci_conf_write(pb->pc, tag, br + 4, bar64);
576 				size = (u_int64_t) PCI_MAPREG_MEM64_SIZE(
577 				      (((u_int64_t) mask64) << 32) | mask);
578 				width = 8;
579 				break;
580 			default:
581 				print_tag(pb->pc, tag);
582 				printf("reserved mapping type 0x%x\n",
583 					PCI_MAPREG_MEM_TYPE(mask));
584 				continue;
585 			}
586 
587 			if (size == 0) {
588 				if (pci_conf_debug) {
589 					print_tag(pb->pc, tag);
590 					printf("MEM%d BAR 0x%x is void\n",
591 					    PCI_MAPREG_MEM_TYPE(mask) ==
592 						PCI_MAPREG_MEM_TYPE_64BIT ?
593 						64 : 32, br);
594 				}
595 				continue;
596 			} else {
597 				if (pci_conf_debug) {
598 					print_tag(pb->pc, tag);
599 					printf("MEM%d BAR 0x%x has size %lx\n",
600 					    PCI_MAPREG_MEM_TYPE(mask) ==
601 						PCI_MAPREG_MEM_TYPE_64BIT ?
602 						64 : 32, br, (unsigned long)size);
603 				}
604 			}
605 
606 			if (pb->nmemwin >= MAX_CONF_MEM) {
607 				printf("pciconf: too many memory windows\n");
608 				return -1;
609 			}
610 
611 			pm = get_mem_desc(pb, size);
612 			pm->dev = pd;
613 			pm->reg = br;
614 			pm->size = size;
615 			pm->align = 4;
616 			pm->prefetch = PCI_MAPREG_MEM_PREFETCHABLE(mask);
617 			if (pci_conf_debug) {
618 				print_tag(pb->pc, tag);
619 				printf("Register 0x%x, memory size %"
620 				    PRIu64 "\n", br, pm->size);
621 			}
622 			pb->nmemwin++;
623 			if (pm->prefetch) {
624 				pb->pmem_total += size;
625 			} else {
626 				pb->mem_total += size;
627 			}
628 		}
629 	}
630 
631 	if (mode & PCI_CONF_MAP_ROM) {
632 		bar = pci_conf_read(pb->pc, tag, PCI_MAPREG_ROM);
633 		pci_conf_write(pb->pc, tag, PCI_MAPREG_ROM, 0xfffffffe);
634 		mask = pci_conf_read(pb->pc, tag, PCI_MAPREG_ROM);
635 		pci_conf_write(pb->pc, tag, PCI_MAPREG_ROM, bar);
636 
637 		if (mask != 0 && mask != 0xffffffff) {
638 			if (pb->nmemwin >= MAX_CONF_MEM) {
639 				printf("pciconf: too many memory windows\n");
640 				return -1;
641 			}
642 			size = (u_int64_t) PCI_MAPREG_MEM_SIZE(mask);
643 
644 			pm = get_mem_desc(pb, size);
645 			pm->dev = pd;
646 			pm->reg = PCI_MAPREG_ROM;
647 			pm->size = size;
648 			pm->align = 4;
649 			pm->prefetch = 1;
650 			if (pci_conf_debug) {
651 				print_tag(pb->pc, tag);
652 				printf("Expansion ROM memory size %"
653 				    PRIu64 "\n", pm->size);
654 			}
655 			pb->nmemwin++;
656 			pb->pmem_total += size;
657 		}
658 	} else {
659 		/* Don't enable ROMs if we aren't going to map them. */
660 		mode &= ~PCI_CONF_ENABLE_ROM;
661 		pd->enable &= ~PCI_CONF_ENABLE_ROM;
662 	}
663 
664 	if (!(mode & PCI_CONF_ENABLE_ROM)) {
665 		/* Ensure ROM is disabled */
666 		bar = pci_conf_read(pb->pc, tag, PCI_MAPREG_ROM);
667 		pci_conf_write(pb->pc, tag, PCI_MAPREG_ROM,
668 		    bar & ~PCI_MAPREG_ROM_ENABLE);
669 	}
670 
671 	return 0;
672 }
673 
674 /************************************************************************/
675 /************************************************************************/
676 /********************   Bus configuration routines   ********************/
677 /************************************************************************/
678 /************************************************************************/
679 static u_int64_t
680 pci_allocate_range(struct extent *ex, u_int64_t amt, int align)
681 {
682 	int	r;
683 	u_long	addr;
684 
685 	r = extent_alloc(ex, amt, align, 0, EX_NOWAIT, &addr);
686 	if (r) {
687 		addr = (u_long) -1;
688 		printf("extent_alloc(%p, %" PRIu64 ", %d) returned %d\n",
689 		    ex, amt, align, r);
690 		extent_print(ex);
691 	}
692 	return (pcireg_t) addr;
693 }
694 
695 static int
696 setup_iowins(pciconf_bus_t *pb)
697 {
698 	pciconf_win_t	*pi;
699 	pciconf_dev_t	*pd;
700 
701 	for (pi=pb->pciiowin; pi < &pb->pciiowin[pb->niowin] ; pi++) {
702 		if (pi->size == 0)
703 			continue;
704 
705 		pd = pi->dev;
706 		pi->address = pci_allocate_range(pb->ioext, pi->size,
707 		    pi->align);
708 		if (pi->address == -1) {
709 			print_tag(pd->pc, pd->tag);
710 			printf("Failed to allocate PCI I/O space (%"
711 			    PRIu64 " req)\n", pi->size);
712 			return -1;
713 		}
714 		if (pd->ppb && pi->reg == 0) {
715 			pd->ppb->ioext = extent_create("pciconf", pi->address,
716 			    pi->address + pi->size, M_DEVBUF, NULL, 0,
717 			    EX_NOWAIT);
718 			if (pd->ppb->ioext == NULL) {
719 				print_tag(pd->pc, pd->tag);
720 				printf("Failed to alloc I/O ext. for bus %d\n",
721 				    pd->ppb->busno);
722 				return -1;
723 			}
724 			continue;
725 		}
726 		if (!pb->io_32bit && pi->address > 0xFFFF) {
727 			pi->address = 0;
728 			pd->enable &= ~PCI_CONF_ENABLE_IO;
729 		} else {
730 			pd->enable |= PCI_CONF_ENABLE_IO;
731 		}
732 		if (pci_conf_debug) {
733 			print_tag(pd->pc, pd->tag);
734 			printf("Putting %" PRIu64 " I/O bytes @ %#" PRIx64
735 			    " (reg %x)\n", pi->size, pi->address, pi->reg);
736 		}
737 		pci_conf_write(pd->pc, pd->tag, pi->reg,
738 		    PCI_MAPREG_IO_ADDR(pi->address) | PCI_MAPREG_TYPE_IO);
739 	}
740 	return 0;
741 }
742 
743 static int
744 setup_memwins(pciconf_bus_t *pb)
745 {
746 	pciconf_win_t	*pm;
747 	pciconf_dev_t	*pd;
748 	pcireg_t	base;
749 	struct extent	*ex;
750 
751 	for (pm=pb->pcimemwin; pm < &pb->pcimemwin[pb->nmemwin] ; pm++) {
752 		if (pm->size == 0)
753 			continue;
754 
755 		pd = pm->dev;
756 		ex = (pm->prefetch) ? pb->pmemext : pb->memext;
757 		pm->address = pci_allocate_range(ex, pm->size, pm->align);
758 		if (pm->address == -1) {
759 			print_tag(pd->pc, pd->tag);
760 			printf(
761 			   "Failed to allocate PCI memory space (%" PRIu64
762 			   " req)\n", pm->size);
763 			return -1;
764 		}
765 		if (pd->ppb && pm->reg == 0) {
766 			ex = extent_create("pciconf", pm->address,
767 			    pm->address + pm->size, M_DEVBUF, NULL, 0,
768 			    EX_NOWAIT);
769 			if (ex == NULL) {
770 				print_tag(pd->pc, pd->tag);
771 				printf("Failed to alloc MEM ext. for bus %d\n",
772 				    pd->ppb->busno);
773 				return -1;
774 			}
775 			if (pm->prefetch) {
776 				pd->ppb->pmemext = ex;
777 			} else {
778 				pd->ppb->memext = ex;
779 			}
780 			continue;
781 		}
782 		if (pm->prefetch && !pb->pmem_64bit &&
783 		    pm->address > 0xFFFFFFFFULL) {
784 			pm->address = 0;
785 			pd->enable &= ~PCI_CONF_ENABLE_MEM;
786 		} else {
787 			pd->enable |= PCI_CONF_ENABLE_MEM;
788 		}
789 		if (pm->reg != PCI_MAPREG_ROM) {
790 			if (pci_conf_debug) {
791 				print_tag(pd->pc, pd->tag);
792 				printf(
793 				    "Putting %" PRIu64 " MEM bytes @ %#"
794 				    PRIx64 " (reg %x)\n", pm->size,
795 				    pm->address, pm->reg);
796 			}
797 			base = pci_conf_read(pd->pc, pd->tag, pm->reg);
798 			base = PCI_MAPREG_MEM_ADDR(pm->address) |
799 			    PCI_MAPREG_MEM_TYPE(base);
800 			pci_conf_write(pd->pc, pd->tag, pm->reg, base);
801 			if (PCI_MAPREG_MEM_TYPE(base) ==
802 			    PCI_MAPREG_MEM_TYPE_64BIT) {
803 				base = (pcireg_t)
804 				    (PCI_MAPREG_MEM64_ADDR(pm->address) >> 32);
805 				pci_conf_write(pd->pc, pd->tag, pm->reg + 4,
806 				    base);
807 			}
808 		}
809 	}
810 	for (pm=pb->pcimemwin; pm < &pb->pcimemwin[pb->nmemwin] ; pm++) {
811 		if (pm->reg == PCI_MAPREG_ROM && pm->address != -1) {
812 			pd = pm->dev;
813 			if (!(pd->enable & PCI_CONF_MAP_ROM))
814 				continue;
815 			if (pci_conf_debug) {
816 				print_tag(pd->pc, pd->tag);
817 				printf(
818 				    "Putting %" PRIu64 " ROM bytes @ %#"
819 				    PRIx64 " (reg %x)\n", pm->size,
820 				    pm->address, pm->reg);
821 			}
822 			base = (pcireg_t) pm->address;
823 			if (pd->enable & PCI_CONF_ENABLE_ROM)
824 				base |= PCI_MAPREG_ROM_ENABLE;
825 
826 			pci_conf_write(pd->pc, pd->tag, pm->reg, base);
827 		}
828 	}
829 	return 0;
830 }
831 
832 /*
833  * Configure I/O, memory, and prefetcable memory spaces, then make
834  * a call to configure_bus().
835  */
836 static int
837 configure_bridge(pciconf_dev_t *pd)
838 {
839 	unsigned long	io_base, io_limit, mem_base, mem_limit;
840 	pciconf_bus_t	*pb;
841 	pcireg_t	io, iohigh, mem, cmd;
842 	int		rv;
843 
844 	pb = pd->ppb;
845 	/* Configure I/O base & limit*/
846 	if (pb->ioext) {
847 		io_base = pb->ioext->ex_start;
848 		io_limit = pb->ioext->ex_end;
849 	} else {
850 		io_base  = 0x1000;	/* 4K */
851 		io_limit = 0x0000;
852 	}
853 	if (pb->io_32bit) {
854 		iohigh =
855 		    ((io_base >> 16) << PCI_BRIDGE_IOHIGH_BASE_SHIFT) |
856 		    ((io_limit >> 16) << PCI_BRIDGE_IOHIGH_LIMIT_SHIFT);
857 	} else {
858 		if (io_limit > 0xFFFF) {
859 			printf("Bus %d bridge does not support 32-bit I/O.  ",
860 			    pb->busno);
861 			printf("Disabling I/O accesses\n");
862 			io_base  = 0x1000;	/* 4K */
863 			io_limit = 0x0000;
864 		}
865 		iohigh = 0;
866 	}
867 	io = pci_conf_read(pb->pc, pd->tag, PCI_BRIDGE_STATIO_REG) &
868 	    (PCI_BRIDGE_STATIO_STATUS_MASK << PCI_BRIDGE_STATIO_STATUS_SHIFT);
869 	io |= (((io_base >> 8) & PCI_BRIDGE_STATIO_IOBASE_MASK)
870 	    << PCI_BRIDGE_STATIO_IOBASE_SHIFT);
871 	io |= (((io_limit >> 8) & PCI_BRIDGE_STATIO_IOLIMIT_MASK)
872 	    << PCI_BRIDGE_STATIO_IOLIMIT_SHIFT);
873 	pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_STATIO_REG, io);
874 	pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_IOHIGH_REG, iohigh);
875 
876 	/* Configure mem base & limit */
877 	if (pb->memext) {
878 		mem_base = pb->memext->ex_start;
879 		mem_limit = pb->memext->ex_end;
880 	} else {
881 		mem_base  = 0x100000;	/* 1M */
882 		mem_limit = 0x000000;
883 	}
884 #if ULONG_MAX > 0xffffffff
885 	if (mem_limit > 0xFFFFFFFFULL) {
886 		printf("Bus %d bridge MEM range out of range.  ", pb->busno);
887 		printf("Disabling MEM accesses\n");
888 		mem_base  = 0x100000;	/* 1M */
889 		mem_limit = 0x000000;
890 	}
891 #endif
892 	mem = (((mem_base >> 20) & PCI_BRIDGE_MEMORY_BASE_MASK)
893 	    << PCI_BRIDGE_MEMORY_BASE_SHIFT);
894 	mem |= (((mem_limit >> 20) & PCI_BRIDGE_MEMORY_LIMIT_MASK)
895 	    << PCI_BRIDGE_MEMORY_LIMIT_SHIFT);
896 	pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_MEMORY_REG, mem);
897 
898 	/* Configure prefetchable mem base & limit */
899 	if (pb->pmemext) {
900 		mem_base = pb->pmemext->ex_start;
901 		mem_limit = pb->pmemext->ex_end;
902 	} else {
903 		mem_base  = 0x100000;	/* 1M */
904 		mem_limit = 0x000000;
905 	}
906 	mem = pci_conf_read(pb->pc, pd->tag, PCI_BRIDGE_PREFETCHMEM_REG);
907 #if ULONG_MAX > 0xffffffff
908 	if (!PCI_BRIDGE_PREFETCHMEM_64BITS(mem) && mem_limit > 0xFFFFFFFFULL) {
909 		printf("Bus %d bridge does not support 64-bit PMEM.  ",
910 		    pb->busno);
911 		printf("Disabling prefetchable-MEM accesses\n");
912 		mem_base  = 0x100000;	/* 1M */
913 		mem_limit = 0x000000;
914 	}
915 #endif
916 	mem = (((mem_base >> 20) & PCI_BRIDGE_PREFETCHMEM_BASE_MASK)
917 	    << PCI_BRIDGE_PREFETCHMEM_BASE_SHIFT);
918 	mem |= (((mem_limit >> 20) & PCI_BRIDGE_PREFETCHMEM_LIMIT_MASK)
919 	    << PCI_BRIDGE_PREFETCHMEM_LIMIT_SHIFT);
920 	pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_PREFETCHMEM_REG, mem);
921 	/*
922 	 * XXX -- 64-bit systems need a lot more than just this...
923 	 */
924 	if (PCI_BRIDGE_PREFETCHMEM_64BITS(mem)) {
925 		mem_base  = (uint64_t) mem_base  >> 32;
926 		mem_limit = (uint64_t) mem_limit >> 32;
927 		pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_PREFETCHBASE32_REG,
928 		    mem_base & 0xffffffff);
929 		pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_PREFETCHLIMIT32_REG,
930 		    mem_limit & 0xffffffff);
931 	}
932 
933 	rv = configure_bus(pb);
934 
935 	if (pb->ioext)
936 		extent_destroy(pb->ioext);
937 	if (pb->memext)
938 		extent_destroy(pb->memext);
939 	if (pb->pmemext)
940 		extent_destroy(pb->pmemext);
941 	if (rv == 0) {
942 		cmd = pci_conf_read(pd->pc, pd->tag, PCI_BRIDGE_CONTROL_REG);
943 		cmd &= PCI_BRIDGE_CONTROL_MASK;
944 		cmd |= (PCI_BRIDGE_CONTROL_PERE | PCI_BRIDGE_CONTROL_SERR)
945 		    << PCI_BRIDGE_CONTROL_SHIFT;
946 		if (pb->fast_b2b) {
947 			cmd |= PCI_BRIDGE_CONTROL_SECFASTB2B
948 			    << PCI_BRIDGE_CONTROL_SHIFT;
949 		}
950 		pci_conf_write(pd->pc, pd->tag, PCI_BRIDGE_CONTROL_REG, cmd);
951 		cmd = pci_conf_read(pd->pc, pd->tag, PCI_COMMAND_STATUS_REG);
952 		cmd |= PCI_COMMAND_IO_ENABLE | PCI_COMMAND_MEM_ENABLE;
953 		pci_conf_write(pd->pc, pd->tag, PCI_COMMAND_STATUS_REG, cmd);
954 	}
955 
956 	return rv;
957 }
958 
959 /*
960  * Calculate latency values, allocate I/O and MEM segments, then set them
961  * up.  If a PCI-PCI bridge is found, configure the bridge separately,
962  * which will cause a recursive call back here.
963  */
964 static int
965 configure_bus(pciconf_bus_t *pb)
966 {
967 	pciconf_dev_t	*pd;
968 	int		def_ltim, max_ltim, band, bus_mhz;
969 
970 	if (pb->ndevs == 0) {
971 		if (pci_conf_debug)
972 			printf("PCI bus %d - no devices\n", pb->busno);
973 		return (1);
974 	}
975 	bus_mhz = pb->freq_66 ? 66 : 33;
976 	max_ltim = pb->max_mingnt * bus_mhz / 4;	/* cvt to cycle count */
977 	band = 4000000;					/* 0.25us cycles/sec */
978 	if (band < pb->bandwidth_used) {
979 		printf("PCI bus %d: Warning: Total bandwidth exceeded!? (%d)\n",
980 		    pb->busno, pb->bandwidth_used);
981 		def_ltim = -1;
982 	} else {
983 		def_ltim = (band - pb->bandwidth_used) / pb->ndevs;
984 		if (def_ltim > pb->min_maxlat)
985 			def_ltim = pb->min_maxlat;
986 		def_ltim = def_ltim * bus_mhz / 4;
987 	}
988 	def_ltim = (def_ltim + 7) & ~7;
989 	max_ltim = (max_ltim + 7) & ~7;
990 
991 	pb->def_ltim = MIN( def_ltim, 255 );
992 	pb->max_ltim = MIN( MAX(max_ltim, def_ltim ), 255 );
993 
994 	/*
995 	 * Now we have what we need to initialize the devices.
996 	 * It would probably be better if we could allocate all of these
997 	 * for all busses at once, but "not right now".  First, get a list
998 	 * of free memory ranges from the m.d. system.
999 	 */
1000 	if (setup_iowins(pb) || setup_memwins(pb)) {
1001 		printf("PCI bus configuration failed: ");
1002 		printf("unable to assign all I/O and memory ranges.");
1003 		return -1;
1004 	}
1005 
1006 	/*
1007 	 * Configure the latency for the devices, and enable them.
1008 	 */
1009 	for (pd=pb->device ; pd < &pb->device[pb->ndevs] ; pd++) {
1010 		pcireg_t cmd, class, misc;
1011 		int	ltim;
1012 
1013 		if (pci_conf_debug) {
1014 			print_tag(pd->pc, pd->tag);
1015 			printf("Configuring device.\n");
1016 		}
1017 		class = pci_conf_read(pd->pc, pd->tag, PCI_CLASS_REG);
1018 		misc = pci_conf_read(pd->pc, pd->tag, PCI_BHLC_REG);
1019 		cmd = pci_conf_read(pd->pc, pd->tag, PCI_COMMAND_STATUS_REG);
1020 		if (pd->enable & PCI_CONF_ENABLE_PARITY)
1021 			cmd |= PCI_COMMAND_PARITY_ENABLE;
1022 		if (pd->enable & PCI_CONF_ENABLE_SERR)
1023 			cmd |= PCI_COMMAND_SERR_ENABLE;
1024 		if (pb->fast_b2b)
1025 			cmd |= PCI_COMMAND_BACKTOBACK_ENABLE;
1026 		if (PCI_CLASS(class) != PCI_CLASS_BRIDGE ||
1027 		    PCI_SUBCLASS(class) != PCI_SUBCLASS_BRIDGE_PCI) {
1028 			if (pd->enable & PCI_CONF_ENABLE_IO)
1029 				cmd |= PCI_COMMAND_IO_ENABLE;
1030 			if (pd->enable & PCI_CONF_ENABLE_MEM)
1031 				cmd |= PCI_COMMAND_MEM_ENABLE;
1032 			if (pd->enable & PCI_CONF_ENABLE_BM)
1033 				cmd |= PCI_COMMAND_MASTER_ENABLE;
1034 			ltim = pd->min_gnt * bus_mhz / 4;
1035 			ltim = MIN (MAX (pb->def_ltim, ltim), pb->max_ltim);
1036 		} else {
1037 			cmd |= PCI_COMMAND_MASTER_ENABLE;
1038 			ltim = MIN (pb->def_ltim, pb->max_ltim);
1039 		}
1040 		if ((pd->enable &
1041 		    (PCI_CONF_ENABLE_MEM|PCI_CONF_ENABLE_IO)) == 0) {
1042 			print_tag(pd->pc, pd->tag);
1043 			printf("Disabled due to lack of resources.\n");
1044 			cmd &= ~(PCI_COMMAND_MASTER_ENABLE |
1045 			    PCI_COMMAND_IO_ENABLE | PCI_COMMAND_MEM_ENABLE);
1046 		}
1047 		pci_conf_write(pd->pc, pd->tag, PCI_COMMAND_STATUS_REG, cmd);
1048 
1049 		misc &= ~((PCI_LATTIMER_MASK << PCI_LATTIMER_SHIFT) |
1050 		    (PCI_CACHELINE_MASK << PCI_CACHELINE_SHIFT));
1051 		misc |= (ltim & PCI_LATTIMER_MASK) << PCI_LATTIMER_SHIFT;
1052 		misc |= ((pb->cacheline_size >> 2) & PCI_CACHELINE_MASK) <<
1053 		    PCI_CACHELINE_SHIFT;
1054 		pci_conf_write(pd->pc, pd->tag, PCI_BHLC_REG, misc);
1055 
1056 		if (pd->ppb) {
1057 			if (configure_bridge(pd) < 0)
1058 				return -1;
1059 			continue;
1060 		}
1061 	}
1062 
1063 	if (pci_conf_debug) {
1064 		printf("PCI bus %d configured\n", pb->busno);
1065 	}
1066 
1067 	return 0;
1068 }
1069 
1070 /*
1071  * Let's configure the PCI bus.
1072  * This consists of basically scanning for all existing devices,
1073  * identifying their needs, and then making another pass over them
1074  * to set:
1075  *	1. I/O addresses
1076  *	2. Memory addresses (Prefetchable and not)
1077  *	3. PCI command register
1078  *	4. The latency part of the PCI BHLC (BIST (Built-In Self Test),
1079  *	    Header type, Latency timer, Cache line size) register
1080  *
1081  * The command register is set to enable fast back-to-back transactions
1082  * if the host bridge says it can handle it.  We also configure
1083  * Master Enable, SERR enable, parity enable, and (if this is not a
1084  * PCI-PCI bridge) the I/O and Memory spaces.  Apparently some devices
1085  * will not report some I/O space.
1086  *
1087  * The latency is computed to be a "fair share" of the bus bandwidth.
1088  * The bus bandwidth variable is initialized to the number of PCI cycles
1089  * in one second.  The number of cycles taken for one transaction by each
1090  * device (MAX_LAT + MIN_GNT) is then subtracted from the bandwidth.
1091  * Care is taken to ensure that the latency timer won't be set such that
1092  * it would exceed the critical time for any device.
1093  *
1094  * This is complicated somewhat due to the presence of bridges.  PCI-PCI
1095  * bridges are probed and configured recursively.
1096  */
1097 int
1098 pci_configure_bus(pci_chipset_tag_t pc, struct extent *ioext,
1099     struct extent *memext, struct extent *pmemext, int firstbus,
1100     int cacheline_size)
1101 {
1102 	pciconf_bus_t	*pb;
1103 	int		rv;
1104 
1105 	pb = kmem_zalloc(sizeof (pciconf_bus_t), KM_NOSLEEP);
1106 	pb->busno = firstbus;
1107 	pb->next_busno = pb->busno + 1;
1108 	pb->last_busno = 255;
1109 	pb->cacheline_size = cacheline_size;
1110 	pb->parent_bus = NULL;
1111 	pb->swiz = 0;
1112 	pb->io_32bit = 1;
1113 	pb->pmem_64bit = 0;
1114 	pb->ioext = ioext;
1115 	pb->memext = memext;
1116 	if (pmemext == NULL) {
1117 		pb->pmemext = memext;
1118 	} else {
1119 		pb->pmemext = pmemext;
1120 	}
1121 	pb->pc = pc;
1122 	pb->io_total = pb->mem_total = pb->pmem_total = 0;
1123 
1124 	rv = probe_bus(pb);
1125 	pb->last_busno = pb->next_busno-1;
1126 	if (rv == 0) {
1127 		rv = configure_bus(pb);
1128 	}
1129 
1130 	/*
1131 	 * All done!
1132 	 */
1133 	kmem_free(pb, sizeof(*pb));
1134 	return rv;
1135 }
1136