Home | History | Annotate | Line # | Download | only in pci
pciconf.c revision 1.18
      1 /*	$NetBSD: pciconf.c,v 1.18 2002/11/08 07:01:26 simonb 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 1.18 2002/11/08 07:01:26 simonb 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 
     78 #include <dev/pci/pcivar.h>
     79 #include <dev/pci/pciconf.h>
     80 #include <dev/pci/pcidevs.h>
     81 
     82 int pci_conf_debug = 0;
     83 
     84 #if !defined(MIN)
     85 #define	MIN(a,b) (((a)<(b))?(a):(b))
     86 #define	MAX(a,b) (((a)>(b))?(a):(b))
     87 #endif
     88 
     89 /* per-bus constants. */
     90 #define MAX_CONF_DEV	32			/* Arbitrary */
     91 #define MAX_CONF_MEM	(3 * MAX_CONF_DEV)	/* Avg. 3 per device -- Arb. */
     92 #define MAX_CONF_IO	(3 * MAX_CONF_DEV)	/* Avg. 1 per device -- Arb. */
     93 
     94 struct _s_pciconf_bus_t;			/* Forward declaration */
     95 
     96 typedef struct _s_pciconf_dev_t {
     97 	int		ipin;
     98 	int		iline;
     99 	int		min_gnt;
    100 	int		max_lat;
    101 	int		enable;
    102 	pcitag_t	tag;
    103 	pci_chipset_tag_t	pc;
    104 	struct _s_pciconf_bus_t	*ppb;		/* I am really a bridge */
    105 } pciconf_dev_t;
    106 
    107 typedef struct _s_pciconf_win_t {
    108 	pciconf_dev_t	*dev;
    109 	int		reg;			/* 0 for busses */
    110 	int		align;
    111 	int		prefetch;
    112 	u_int64_t	size;
    113 	u_int64_t	address;
    114 } pciconf_win_t;
    115 
    116 typedef struct _s_pciconf_bus_t {
    117 	int		busno;
    118 	int		next_busno;
    119 	int		last_busno;
    120 	int		max_mingnt;
    121 	int		min_maxlat;
    122 	int		cacheline_size;
    123 	int		prefetch;
    124 	int		fast_b2b;
    125 	int		freq_66;
    126 	int		def_ltim;
    127 	int		max_ltim;
    128 	int		bandwidth_used;
    129 	int		swiz;
    130 	int		io_32bit;
    131 	int		pmem_64bit;
    132 
    133 	int		ndevs;
    134 	pciconf_dev_t	device[MAX_CONF_DEV];
    135 
    136 	/* These should be sorted in order of decreasing size */
    137 	int		nmemwin;
    138 	pciconf_win_t	pcimemwin[MAX_CONF_MEM];
    139 	int		niowin;
    140 	pciconf_win_t	pciiowin[MAX_CONF_IO];
    141 
    142 	bus_size_t	io_total;
    143 	bus_size_t	mem_total;
    144 	bus_size_t	pmem_total;
    145 
    146 	struct extent	*ioext;
    147 	struct extent	*memext;
    148 	struct extent	*pmemext;
    149 
    150 	pci_chipset_tag_t	pc;
    151 	struct _s_pciconf_bus_t *parent_bus;
    152 } pciconf_bus_t;
    153 
    154 static int	probe_bus(pciconf_bus_t *);
    155 static void	alloc_busno(pciconf_bus_t *, pciconf_bus_t *);
    156 static void	set_busreg(pci_chipset_tag_t, pcitag_t, int, int, int);
    157 static int	pci_do_device_query(pciconf_bus_t *, pcitag_t, int, int, int);
    158 static int	setup_iowins(pciconf_bus_t *);
    159 static int	setup_memwins(pciconf_bus_t *);
    160 static int	configure_bridge(pciconf_dev_t *);
    161 static int	configure_bus(pciconf_bus_t *);
    162 static u_int64_t	pci_allocate_range(struct extent *, u_int64_t, int);
    163 static pciconf_win_t	*get_io_desc(pciconf_bus_t *, bus_size_t);
    164 static pciconf_win_t	*get_mem_desc(pciconf_bus_t *, bus_size_t);
    165 static pciconf_bus_t	*query_bus(pciconf_bus_t *, pciconf_dev_t *, int);
    166 
    167 static void	print_tag(pci_chipset_tag_t, pcitag_t);
    168 
    169 static void
    170 print_tag(pci_chipset_tag_t pc, pcitag_t tag)
    171 {
    172 	int	bus, dev, func;
    173 
    174 	pci_decompose_tag(pc, tag, &bus, &dev, &func);
    175 	printf("PCI: bus %d, device %d, function %d: ", bus, dev, func);
    176 }
    177 
    178 /************************************************************************/
    179 /************************************************************************/
    180 /***********************   Bus probing routines   ***********************/
    181 /************************************************************************/
    182 /************************************************************************/
    183 static pciconf_win_t *
    184 get_io_desc(pciconf_bus_t *pb, bus_size_t size)
    185 {
    186 	int	i, n;
    187 
    188 	n = pb->niowin;
    189 	for (i=n; i > 0 && size > pb->pciiowin[i-1].size; i--)
    190 		pb->pciiowin[i] = pb->pciiowin[i-1]; /* struct copy */
    191 	return &pb->pciiowin[i];
    192 }
    193 
    194 static pciconf_win_t *
    195 get_mem_desc(pciconf_bus_t *pb, bus_size_t size)
    196 {
    197 	int	i, n;
    198 
    199 	n = pb->nmemwin;
    200 	for (i=n; i > 0 && size > pb->pcimemwin[i-1].size; i--)
    201 		pb->pcimemwin[i] = pb->pcimemwin[i-1]; /* struct copy */
    202 	return &pb->pcimemwin[i];
    203 }
    204 
    205 /*
    206  * Set up bus common stuff, then loop over devices & functions.
    207  * If we find something, call pci_do_device_query()).
    208  */
    209 static int
    210 probe_bus(pciconf_bus_t *pb)
    211 {
    212 	int device, maxdevs;
    213 #ifdef __PCI_BUS_DEVORDER
    214 	char devs[32];
    215 	int  i;
    216 #endif
    217 
    218 	maxdevs = pci_bus_maxdevs(pb->pc, pb->busno);
    219 	pb->ndevs = 0;
    220 	pb->niowin = 0;
    221 	pb->nmemwin = 0;
    222 	pb->freq_66 = 1;
    223 	pb->fast_b2b = 1;
    224 	pb->prefetch = 1;
    225 	pb->max_mingnt = 0;	/* we are looking for the maximum */
    226 	pb->min_maxlat = 0x100;	/* we are looking for the minimum */
    227 	pb->bandwidth_used = 0;
    228 
    229 #ifdef __PCI_BUS_DEVORDER
    230 	pci_bus_devorder(pb->pc, pb->busno, devs);
    231 	for (i = 0; (device = devs[i]) < 32 && device >= 0; i++) {
    232 #else
    233 	for (device = 0; device < maxdevs; device++) {
    234 #endif
    235 		pcitag_t tag;
    236 		pcireg_t id, bhlcr;
    237 		int function, nfunction;
    238 		int confmode;
    239 
    240 		tag = pci_make_tag(pb->pc, pb->busno, device, 0);
    241 		if (pci_conf_debug) {
    242 			print_tag(pb->pc, tag);
    243 		}
    244 		id = pci_conf_read(pb->pc, tag, PCI_ID_REG);
    245 
    246 		if (pci_conf_debug) {
    247 			printf("id=%x: Vendor=%x, Product=%x\n",
    248 			    id, PCI_VENDOR(id),PCI_PRODUCT(id));
    249 		}
    250 		/* Invalid vendor ID value? */
    251 		if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
    252 			continue;
    253 
    254 		bhlcr = pci_conf_read(pb->pc, tag, PCI_BHLC_REG);
    255 		nfunction = PCI_HDRTYPE_MULTIFN(bhlcr) ? 8 : 1;
    256 		for (function = 0 ; function < nfunction ; function++) {
    257 			tag = pci_make_tag(pb->pc, pb->busno, device, function);
    258 			id = pci_conf_read(pb->pc, tag, PCI_ID_REG);
    259 			if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
    260 				continue;
    261 			if (pb->ndevs+1 < MAX_CONF_DEV) {
    262 				if (pci_conf_debug) {
    263 					print_tag(pb->pc, tag);
    264 					printf("Found dev 0x%04x 0x%04x -- "
    265 					    "really probing.\n",
    266 					PCI_VENDOR(id), PCI_PRODUCT(id));
    267 				}
    268 #ifdef __HAVE_PCI_CONF_HOOK
    269 				confmode = pci_conf_hook(pb->pc, pb->busno,
    270 				    device, function, id);
    271 				if (confmode == 0)
    272 					continue;
    273 #else
    274 				/*
    275 				 * Don't enable expansion ROMS -- some cards
    276 				 * share address decoders between the EXPROM
    277 				 * and PCI memory space, and enabling the ROM
    278 				 * when not needed will cause all sorts of
    279 				 * lossage.
    280 				 */
    281 				confmode = PCI_CONF_ALL & ~PCI_CONF_MAP_ROM;
    282 #endif
    283 				if (pci_do_device_query(pb, tag, device,
    284 				    function, confmode))
    285 					return -1;
    286 				pb->ndevs++;
    287 			}
    288 		}
    289 	}
    290 	return 0;
    291 }
    292 
    293 static void
    294 alloc_busno(pciconf_bus_t *parent, pciconf_bus_t *pb)
    295 {
    296 	pb->busno = parent->next_busno;
    297 	pb->next_busno = pb->busno + 1;
    298 }
    299 
    300 static void
    301 set_busreg(pci_chipset_tag_t pc, pcitag_t tag, int prim, int sec, int sub)
    302 {
    303 	pcireg_t	busreg;
    304 
    305 	busreg  =  prim << PCI_BRIDGE_BUS_PRIMARY_SHIFT;
    306 	busreg |=   sec << PCI_BRIDGE_BUS_SECONDARY_SHIFT;
    307 	busreg |=   sub << PCI_BRIDGE_BUS_SUBORDINATE_SHIFT;
    308 	pci_conf_write(pc, tag, PCI_BRIDGE_BUS_REG, busreg);
    309 }
    310 
    311 static pciconf_bus_t *
    312 query_bus(pciconf_bus_t *parent, pciconf_dev_t *pd, int dev)
    313 {
    314 	pciconf_bus_t	*pb;
    315 	pcireg_t	io, pmem;
    316 	pciconf_win_t	*pi, *pm;
    317 
    318 	pb = malloc (sizeof (pciconf_bus_t), M_DEVBUF, M_NOWAIT);
    319 	if (!pb)
    320 		panic("Unable to allocate memory for PCI configuration.");
    321 
    322 	pb->cacheline_size = parent->cacheline_size;
    323 	pb->parent_bus = parent;
    324 	alloc_busno(parent, pb);
    325 
    326 	set_busreg(parent->pc, pd->tag, parent->busno, pb->busno, 0xff);
    327 
    328 	pb->swiz = parent->swiz + dev;
    329 
    330 	pb->ioext = NULL;
    331 	pb->memext = NULL;
    332 	pb->pmemext = NULL;
    333 	pb->pc = parent->pc;
    334 	pb->io_total = pb->mem_total = pb->pmem_total = 0;
    335 
    336 	pb->io_32bit = 0;
    337 	if (parent->io_32bit) {
    338 		io = pci_conf_read(parent->pc, pd->tag, PCI_BRIDGE_STATIO_REG);
    339 		if (PCI_BRIDGE_IO_32BITS(io)) {
    340 			pb->io_32bit = 1;
    341 		}
    342 	}
    343 
    344 	pb->pmem_64bit = 0;
    345 	if (parent->pmem_64bit) {
    346 		pmem = pci_conf_read(parent->pc, pd->tag,
    347 		    PCI_BRIDGE_PREFETCHMEM_REG);
    348 		if (PCI_BRIDGE_PREFETCHMEM_64BITS(pmem)) {
    349 			pb->pmem_64bit = 1;
    350 		}
    351 	}
    352 
    353 	if (probe_bus(pb)) {
    354 		printf("Failed to probe bus %d\n", pb->busno);
    355 		goto err;
    356 	}
    357 
    358 	/* We have found all subordinate busses now, reprogram busreg. */
    359 	pb->last_busno = pb->next_busno-1;
    360 	parent->next_busno = pb->next_busno;
    361 	set_busreg(parent->pc, pd->tag, parent->busno, pb->busno,
    362 		   pb->last_busno);
    363 	if (pci_conf_debug)
    364 		printf("PCI bus bridge (parent %d) covers busses %d-%d\n",
    365 			parent->busno, pb->busno, pb->last_busno);
    366 
    367 	if (pb->io_total > 0) {
    368 		if (parent->niowin >= MAX_CONF_IO) {
    369 			printf("pciconf: too many I/O windows\n");
    370 			goto err;
    371 		}
    372 		pb->io_total |= 0xfff;	/* Round up */
    373 		pi = get_io_desc(parent, pb->io_total);
    374 		pi->dev = pd;
    375 		pi->reg = 0;
    376 		pi->size = pb->io_total;
    377 		pi->align = 0x1000;	/* 4K alignment */
    378 		pi->prefetch = 0;
    379 		parent->niowin++;
    380 		parent->io_total += pb->io_total;
    381 	}
    382 
    383 	if (pb->mem_total > 0) {
    384 		if (parent->nmemwin >= MAX_CONF_MEM) {
    385 			printf("pciconf: too many MEM windows\n");
    386 			goto err;
    387 		}
    388 		pb->mem_total |= 0xfffff;	/* Round up */
    389 		pm = get_mem_desc(parent, pb->mem_total);
    390 		pm->dev = pd;
    391 		pm->reg = 0;
    392 		pm->size = pb->mem_total;
    393 		pm->align = 0x100000;	/* 1M alignment */
    394 		pm->prefetch = 0;
    395 		parent->nmemwin++;
    396 		parent->mem_total += pb->mem_total;
    397 	}
    398 
    399 	if (pb->pmem_total > 0) {
    400 		if (parent->nmemwin >= MAX_CONF_MEM) {
    401 			printf("pciconf: too many MEM windows\n");
    402 			goto err;
    403 		}
    404 		pb->pmem_total |= 0xfffff;	/* Round up */
    405 		pm = get_mem_desc(parent, pb->pmem_total);
    406 		pm->dev = pd;
    407 		pm->reg = 0;
    408 		pm->size = pb->pmem_total;
    409 		pm->align = 0x100000;		/* 1M alignment */
    410 		pm->prefetch = 1;
    411 		parent->nmemwin++;
    412 		parent->pmem_total += pb->pmem_total;
    413 	}
    414 
    415 	return pb;
    416 err:
    417 	free(pb, M_DEVBUF);
    418 	return NULL;
    419 }
    420 
    421 static int
    422 pci_do_device_query(pciconf_bus_t *pb, pcitag_t tag, int dev, int func, int mode)
    423 {
    424 	pciconf_dev_t	*pd;
    425 	pciconf_win_t	*pi, *pm;
    426 	pcireg_t	class, cmd, icr, bar, mask, bar64, mask64;
    427 	u_int64_t	size;
    428 	int		br, width;
    429 
    430 	pd = &pb->device[pb->ndevs];
    431 	pd->pc = pb->pc;
    432 	pd->tag = tag;
    433 	pd->ppb = NULL;
    434 	pd->enable = mode;
    435 
    436 	class = pci_conf_read(pb->pc, tag, PCI_CLASS_REG);
    437 
    438 	cmd = pci_conf_read(pb->pc, tag, PCI_COMMAND_STATUS_REG);
    439 
    440 	if (PCI_CLASS(class) != PCI_CLASS_BRIDGE) {
    441 		cmd &= ~(PCI_COMMAND_MASTER_ENABLE |
    442 		    PCI_COMMAND_IO_ENABLE | PCI_COMMAND_MEM_ENABLE);
    443 		pci_conf_write(pb->pc, tag, PCI_COMMAND_STATUS_REG, cmd);
    444 	} else if (pci_conf_debug) {
    445 		print_tag(pb->pc, tag);
    446 		printf("device is a bridge; not clearing enables\n");
    447 	}
    448 
    449 	if ((cmd & PCI_STATUS_BACKTOBACK_SUPPORT) == 0)
    450 		pb->fast_b2b = 0;
    451 
    452 	if ((cmd & PCI_STATUS_66MHZ_SUPPORT) == 0)
    453 		pb->freq_66 = 0;
    454 
    455 	if (   (PCI_CLASS(class) == PCI_CLASS_BRIDGE)
    456 	    && (PCI_SUBCLASS(class) == PCI_SUBCLASS_BRIDGE_PCI)) {
    457 		pd->ppb = query_bus(pb, pd, dev);
    458 		if (pd->ppb == NULL)
    459 			return -1;
    460 		return 0;
    461 	}
    462 
    463 	icr = pci_conf_read(pb->pc, tag, PCI_INTERRUPT_REG);
    464 	pd->ipin = PCI_INTERRUPT_PIN(icr);
    465 	pd->iline = PCI_INTERRUPT_LINE(icr);
    466 	pd->min_gnt = PCI_MIN_GNT(icr);
    467 	pd->max_lat = PCI_MAX_LAT(icr);
    468 	if (pd->iline || pd->ipin) {
    469 		pci_conf_interrupt(pb->pc, pb->busno, dev, pd->ipin, pb->swiz,
    470 		    &pd->iline);
    471 		icr &= ~(PCI_INTERRUPT_LINE_MASK << PCI_INTERRUPT_LINE_SHIFT);
    472 		icr |= (pd->iline << PCI_INTERRUPT_LINE_SHIFT);
    473 		pci_conf_write(pb->pc, tag, PCI_INTERRUPT_REG, icr);
    474 	}
    475 
    476 	if (pd->min_gnt != 0 || pd->max_lat != 0) {
    477 		if (pd->min_gnt != 0 && pd->min_gnt > pb->max_mingnt)
    478 			pb->max_mingnt = pd->min_gnt;
    479 
    480 		if (pd->max_lat != 0 && pd->max_lat < pb->min_maxlat)
    481 			pb->min_maxlat = pd->max_lat;
    482 
    483 		pb->bandwidth_used += pd->min_gnt * 4000000 /
    484 				(pd->min_gnt + pd->max_lat);
    485 	}
    486 
    487 	width = 4;
    488 	for (br = PCI_MAPREG_START; br < PCI_MAPREG_END; br += width) {
    489 #if 0
    490 /* XXX Should only ignore if IDE not in legacy mode? */
    491 		if (PCI_CLASS(class) == PCI_CLASS_MASS_STORAGE &&
    492 		    PCI_SUBCLASS(class) == PCI_SUBCLASS_MASS_STORAGE_IDE) {
    493 			break;
    494 		}
    495 #endif
    496 		bar = pci_conf_read(pb->pc, tag, br);
    497 		pci_conf_write(pb->pc, tag, br, 0xffffffff);
    498 		mask = pci_conf_read(pb->pc, tag, br);
    499 		pci_conf_write(pb->pc, tag, br, bar);
    500 		width = 4;
    501 
    502 		if (   (mode & PCI_CONF_MAP_IO)
    503 		    && (PCI_MAPREG_TYPE(mask) == PCI_MAPREG_TYPE_IO)) {
    504 			/*
    505 			 * Upper 16 bits must be one.  Devices may hardwire
    506 			 * them to zero, though, per PCI 2.2, 6.2.5.1, p 203.
    507 			 */
    508 			mask |= 0xffff0000;
    509 
    510 			size = PCI_MAPREG_IO_SIZE(mask);
    511 			if (size == 0) {
    512 				if (pci_conf_debug) {
    513 					print_tag(pb->pc, tag);
    514 					printf("I/O BAR 0x%x is void\n", br);
    515 				}
    516 				continue;
    517 			}
    518 
    519 			if (pb->niowin >= MAX_CONF_IO) {
    520 				printf("pciconf: too many I/O windows\n");
    521 				return -1;
    522 			}
    523 
    524 			pi = get_io_desc(pb, size);
    525 			pi->dev = pd;
    526 			pi->reg = br;
    527 			pi->size = (u_int64_t) size;
    528 			pi->align = 4;
    529 			pi->prefetch = 0;
    530 			if (pci_conf_debug) {
    531 				print_tag(pb->pc, tag);
    532 				printf("Register 0x%x, I/O size %llu\n",
    533 				    br, pi->size);
    534 			}
    535 			pb->niowin++;
    536 			pb->io_total += size;
    537 		} else if ((mode & PCI_CONF_MAP_MEM)
    538 			   && (PCI_MAPREG_TYPE(mask) == PCI_MAPREG_TYPE_MEM)) {
    539 			switch (PCI_MAPREG_MEM_TYPE(mask)) {
    540 			case PCI_MAPREG_MEM_TYPE_32BIT:
    541 			case PCI_MAPREG_MEM_TYPE_32BIT_1M:
    542 				size = (u_int64_t) PCI_MAPREG_MEM_SIZE(mask);
    543 				break;
    544 			case PCI_MAPREG_MEM_TYPE_64BIT:
    545 				bar64 = pci_conf_read(pb->pc, tag, br + 4);
    546 				pci_conf_write(pb->pc, tag, br + 4, 0xffffffff);
    547 				mask64 = pci_conf_read(pb->pc, tag, br + 4);
    548 				pci_conf_write(pb->pc, tag, br + 4, bar64);
    549 				size = (u_int64_t) PCI_MAPREG_MEM64_SIZE(
    550 				      (((u_int64_t) mask64) << 32) | mask);
    551 				width = 8;
    552 				break;
    553 			default:
    554 				print_tag(pb->pc, tag);
    555 				printf("reserved mapping type 0x%x\n",
    556 					PCI_MAPREG_MEM_TYPE(mask));
    557 				continue;
    558 			}
    559 
    560 			if (size == 0) {
    561 				if (pci_conf_debug) {
    562 					print_tag(pb->pc, tag);
    563 					printf("MEM%d BAR 0x%x is void\n",
    564 					    PCI_MAPREG_MEM_TYPE(mask) ==
    565 						PCI_MAPREG_MEM_TYPE_64BIT ?
    566 						64 : 32, br);
    567 				}
    568 				continue;
    569 			} else {
    570 				if (pci_conf_debug) {
    571 					print_tag(pb->pc, tag);
    572 					printf("MEM%d BAR 0x%x has size %lx\n",
    573 					    PCI_MAPREG_MEM_TYPE(mask) ==
    574 						PCI_MAPREG_MEM_TYPE_64BIT ?
    575 						64 : 32, br, (unsigned long)size);
    576 				}
    577 			}
    578 
    579 			if (pb->nmemwin >= MAX_CONF_MEM) {
    580 				printf("pciconf: too many memory windows\n");
    581 				return -1;
    582 			}
    583 
    584 			pm = get_mem_desc(pb, size);
    585 			pm->dev = pd;
    586 			pm->reg = br;
    587 			pm->size = size;
    588 			pm->align = 4;
    589 			pm->prefetch = PCI_MAPREG_MEM_PREFETCHABLE(mask);
    590 			if (pci_conf_debug) {
    591 				print_tag(pb->pc, tag);
    592 				printf("Register 0x%x, memory size %llu\n",
    593 				    br, pm->size);
    594 			}
    595 			pb->nmemwin++;
    596 			if (pm->prefetch) {
    597 				pb->pmem_total += size;
    598 			} else {
    599 				pb->mem_total += size;
    600 			}
    601 		}
    602 	}
    603 
    604 	if (mode & PCI_CONF_MAP_ROM) {
    605 		bar = pci_conf_read(pb->pc, tag, PCI_MAPREG_ROM);
    606 		pci_conf_write(pb->pc, tag, PCI_MAPREG_ROM, 0xfffffffe);
    607 		mask = pci_conf_read(pb->pc, tag, PCI_MAPREG_ROM);
    608 		pci_conf_write(pb->pc, tag, PCI_MAPREG_ROM, bar);
    609 
    610 		if (mask != 0 && mask != 0xffffffff) {
    611 			if (pb->nmemwin >= MAX_CONF_MEM) {
    612 				printf("pciconf: too many memory windows\n");
    613 				return -1;
    614 			}
    615 			size = (u_int64_t) PCI_MAPREG_MEM_SIZE(mask);
    616 
    617 			pm = get_mem_desc(pb, size);
    618 			pm->dev = pd;
    619 			pm->reg = PCI_MAPREG_ROM;
    620 			pm->size = size;
    621 			pm->align = 4;
    622 			pm->prefetch = 1;
    623 			if (pci_conf_debug) {
    624 				print_tag(pb->pc, tag);
    625 				printf("Expansion ROM memory size %llu\n", pm->size);
    626 			}
    627 			pb->nmemwin++;
    628 			pb->pmem_total += size;
    629 		}
    630 	} else {
    631 		/* Ensure ROM is disabled */
    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,
    636 		    bar & ~PCI_MAPREG_ROM_ENABLE);
    637 	}
    638 
    639 	return 0;
    640 }
    641 
    642 /************************************************************************/
    643 /************************************************************************/
    644 /********************   Bus configuration routines   ********************/
    645 /************************************************************************/
    646 /************************************************************************/
    647 static u_int64_t
    648 pci_allocate_range(struct extent *ex, u_int64_t amt, int align)
    649 {
    650 	int	r;
    651 	u_long	addr;
    652 
    653 	r = extent_alloc(ex, amt, align, 0, EX_NOWAIT, &addr);
    654 	if (r) {
    655 		addr = (u_long) -1;
    656 		printf("extent_alloc(%p, %llu, %d) returned %d\n",
    657 		    ex, amt, align, r);
    658 		extent_print(ex);
    659 	}
    660 	return (pcireg_t) addr;
    661 }
    662 
    663 static int
    664 setup_iowins(pciconf_bus_t *pb)
    665 {
    666 	pciconf_win_t	*pi;
    667 	pciconf_dev_t	*pd;
    668 
    669 	for (pi=pb->pciiowin; pi < &pb->pciiowin[pb->niowin] ; pi++) {
    670 		if (pi->size == 0)
    671 			continue;
    672 
    673 		pd = pi->dev;
    674 		pi->address = pci_allocate_range(pb->ioext, pi->size,
    675 		    pi->align);
    676 		if (pi->address == -1) {
    677 			print_tag(pd->pc, pd->tag);
    678 			printf("Failed to allocate PCI I/O space (%llu req)\n",
    679 			   pi->size);
    680 			return -1;
    681 		}
    682 		if (!pb->io_32bit && pi->address > 0xFFFF) {
    683 			pi->address = 0;
    684 			pd->enable = 0;
    685 		}
    686 		if (pd->ppb && pi->reg == 0) {
    687 			pd->ppb->ioext = extent_create("pciconf", pi->address,
    688 			    pi->address + pi->size, M_DEVBUF, NULL, 0,
    689 			    EX_NOWAIT);
    690 			if (pd->ppb->ioext == NULL) {
    691 				print_tag(pd->pc, pd->tag);
    692 				printf("Failed to alloc I/O ext. for bus %d\n",
    693 				    pd->ppb->busno);
    694 				return -1;
    695 			}
    696 			continue;
    697 		}
    698 		pd->enable |= PCI_CONF_ENABLE_IO;
    699 		if (pci_conf_debug) {
    700 			print_tag(pd->pc, pd->tag);
    701 			printf("Putting %llu I/O bytes @ %#llx (reg %x)\n",
    702 			    pi->size, pi->address, pi->reg);
    703 		}
    704 		pci_conf_write(pd->pc, pd->tag, pi->reg,
    705 		    PCI_MAPREG_IO_ADDR(pi->address) | PCI_MAPREG_TYPE_IO);
    706 	}
    707 	return 0;
    708 }
    709 
    710 static int
    711 setup_memwins(pciconf_bus_t *pb)
    712 {
    713 	pciconf_win_t	*pm;
    714 	pciconf_dev_t	*pd;
    715 	pcireg_t	base;
    716 	struct extent	*ex;
    717 
    718 	for (pm=pb->pcimemwin; pm < &pb->pcimemwin[pb->nmemwin] ; pm++) {
    719 		if (pm->size == 0)
    720 			continue;
    721 
    722 		pd = pm->dev;
    723 		ex = (pm->prefetch) ? pb->pmemext : pb->memext;
    724 		pm->address = pci_allocate_range(ex, pm->size, pm->align);
    725 		if (pm->address == -1) {
    726 			print_tag(pd->pc, pd->tag);
    727 			printf(
    728 			   "Failed to allocate PCI memory space (%llu req)\n",
    729 			   pm->size);
    730 			return -1;
    731 		}
    732 		if (pd->ppb && pm->reg == 0) {
    733 			ex = extent_create("pciconf", pm->address,
    734 			    pm->address + pm->size, M_DEVBUF, NULL, 0,
    735 			    EX_NOWAIT);
    736 			if (ex == NULL) {
    737 				print_tag(pd->pc, pd->tag);
    738 				printf("Failed to alloc MEM ext. for bus %d\n",
    739 				    pd->ppb->busno);
    740 				return -1;
    741 			}
    742 			if (pm->prefetch) {
    743 				pd->ppb->pmemext = ex;
    744 			} else {
    745 				pd->ppb->memext = ex;
    746 			}
    747 			continue;
    748 		}
    749 		if (pm->prefetch && !pb->pmem_64bit &&
    750 		    pm->address > 0xFFFFFFFFULL) {
    751 			pm->address = 0;
    752 			pd->enable = 0;
    753 		} else {
    754 			pd->enable |= PCI_CONF_ENABLE_MEM;
    755 		}
    756 		if (pm->reg != PCI_MAPREG_ROM) {
    757 			if (pci_conf_debug) {
    758 				print_tag(pd->pc, pd->tag);
    759 				printf(
    760 				    "Putting %llu MEM bytes @ %#llx (reg %x)\n",
    761 				     pm->size, pm->address, pm->reg);
    762 			}
    763 			base = pci_conf_read(pd->pc, pd->tag, pm->reg);
    764 			base = PCI_MAPREG_MEM_ADDR(pm->address) |
    765 			    PCI_MAPREG_MEM_TYPE(base);
    766 			pci_conf_write(pd->pc, pd->tag, pm->reg, base);
    767 			if (PCI_MAPREG_MEM_TYPE(base) ==
    768 			    PCI_MAPREG_MEM_TYPE_64BIT) {
    769 				base = (pcireg_t)
    770 				    (PCI_MAPREG_MEM64_ADDR(pm->address) >> 32);
    771 				pci_conf_write(pd->pc, pd->tag, pm->reg + 4,
    772 				    base);
    773 			}
    774 		}
    775 	}
    776 	for (pm=pb->pcimemwin; pm < &pb->pcimemwin[pb->nmemwin] ; pm++) {
    777 		if (pm->reg == PCI_MAPREG_ROM && pm->address != -1) {
    778 			pd = pm->dev;
    779 			if (pci_conf_debug) {
    780 				print_tag(pd->pc, pd->tag);
    781 				printf(
    782 				    "Putting %llu ROM bytes @ %#llx (reg %x)\n",
    783 				    pm->size, pm->address, pm->reg);
    784 			}
    785 			base = (pcireg_t) (pm->address | PCI_MAPREG_ROM_ENABLE);
    786 			pci_conf_write(pd->pc, pd->tag, pm->reg, base);
    787 		}
    788 	}
    789 	return 0;
    790 }
    791 
    792 /*
    793  * Configure I/O, memory, and prefetcable memory spaces, then make
    794  * a call to configure_bus().
    795  */
    796 static int
    797 configure_bridge(pciconf_dev_t *pd)
    798 {
    799 	unsigned long	io_base, io_limit, mem_base, mem_limit;
    800 	pciconf_bus_t	*pb;
    801 	pcireg_t	io, iohigh, mem, cmd;
    802 	int		rv;
    803 
    804 	pb = pd->ppb;
    805 	/* Configure I/O base & limit*/
    806 	if (pb->ioext) {
    807 		io_base = pb->ioext->ex_start;
    808 		io_limit = pb->ioext->ex_end;
    809 	} else {
    810 		io_base  = 0x1000;	/* 4K */
    811 		io_limit = 0x0000;
    812 	}
    813 	if (pb->io_32bit) {
    814 		iohigh =
    815 		    ((io_base >> 16) << PCI_BRIDGE_IOHIGH_BASE_SHIFT) |
    816 		    ((io_limit >> 16) << PCI_BRIDGE_IOHIGH_LIMIT_SHIFT);
    817 	} else {
    818 		if (io_limit > 0xFFFF) {
    819 			printf("Bus %d bridge does not support 32-bit I/O.  ",
    820 			    pb->busno);
    821 			printf("Disabling I/O accesses\n");
    822 			io_base  = 0x1000;	/* 4K */
    823 			io_limit = 0x0000;
    824 		}
    825 		iohigh = 0;
    826 	}
    827 	io = pci_conf_read(pb->pc, pd->tag, PCI_BRIDGE_STATIO_REG) &
    828 	    (PCI_BRIDGE_STATIO_STATUS_MASK << PCI_BRIDGE_STATIO_STATUS_SHIFT);
    829 	io |= (((io_base >> 8) & PCI_BRIDGE_STATIO_IOBASE_MASK)
    830 	    << PCI_BRIDGE_STATIO_IOBASE_SHIFT);
    831 	io |= (((io_limit >> 8) & PCI_BRIDGE_STATIO_IOLIMIT_MASK)
    832 	    << PCI_BRIDGE_STATIO_IOLIMIT_SHIFT);
    833 	pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_STATIO_REG, io);
    834 	pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_IOHIGH_REG, iohigh);
    835 
    836 	/* Configure mem base & limit */
    837 	if (pb->memext) {
    838 		mem_base = pb->memext->ex_start;
    839 		mem_limit = pb->memext->ex_end;
    840 	} else {
    841 		mem_base  = 0x100000;	/* 1M */
    842 		mem_limit = 0x000000;
    843 	}
    844 	if (mem_limit > 0xFFFFFFFFULL) {
    845 		printf("Bus %d bridge MEM range out of range.  ", pb->busno);
    846 		printf("Disabling MEM accesses\n");
    847 		mem_base  = 0x100000;	/* 1M */
    848 		mem_limit = 0x000000;
    849 	}
    850 	mem = (((mem_base >> 20) & PCI_BRIDGE_MEMORY_BASE_MASK)
    851 	    << PCI_BRIDGE_MEMORY_BASE_SHIFT);
    852 	mem |= (((mem_limit >> 20) & PCI_BRIDGE_MEMORY_LIMIT_MASK)
    853 	    << PCI_BRIDGE_MEMORY_LIMIT_SHIFT);
    854 	pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_MEMORY_REG, mem);
    855 
    856 	/* Configure prefetchable mem base & limit */
    857 	if (pb->pmemext) {
    858 		mem_base = pb->pmemext->ex_start;
    859 		mem_limit = pb->pmemext->ex_end;
    860 	} else {
    861 		mem_base  = 0x100000;	/* 1M */
    862 		mem_limit = 0x000000;
    863 	}
    864 	mem = pci_conf_read(pb->pc, pd->tag, PCI_BRIDGE_PREFETCHMEM_REG);
    865 	if (!PCI_BRIDGE_PREFETCHMEM_64BITS(mem) && mem_limit > 0xFFFFFFFFULL) {
    866 		printf("Bus %d bridge does not support 64-bit PMEM.  ",
    867 		    pb->busno);
    868 		printf("Disabling prefetchable-MEM accesses\n");
    869 		mem_base  = 0x100000;	/* 1M */
    870 		mem_limit = 0x000000;
    871 	}
    872 	mem = (((mem_base >> 20) & PCI_BRIDGE_PREFETCHMEM_BASE_MASK)
    873 	    << PCI_BRIDGE_PREFETCHMEM_BASE_SHIFT);
    874 	mem |= (((mem_limit >> 20) & PCI_BRIDGE_PREFETCHMEM_LIMIT_MASK)
    875 	    << PCI_BRIDGE_PREFETCHMEM_LIMIT_SHIFT);
    876 	pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_PREFETCHMEM_REG, mem);
    877 	/*
    878 	 * XXX -- 64-bit systems need a lot more than just this...
    879 	 */
    880 	if (sizeof(u_long) > 4) {
    881 		mem_base  = (int64_t) mem_base  >> 32;
    882 		mem_limit = (int64_t) mem_limit >> 32;
    883 	}
    884 	pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_PREFETCHBASE32_REG,
    885 	    mem_base & 0xffffffff);
    886 	pci_conf_write(pb->pc, pd->tag, PCI_BRIDGE_PREFETCHLIMIT32_REG,
    887 	    mem_limit & 0xffffffff);
    888 
    889 	rv = configure_bus(pb);
    890 
    891 	if (pb->ioext)
    892 		extent_destroy(pb->ioext);
    893 	if (pb->memext)
    894 		extent_destroy(pb->memext);
    895 	if (pb->pmemext)
    896 		extent_destroy(pb->pmemext);
    897 	if (rv == 0) {
    898 		cmd = pci_conf_read(pd->pc, pd->tag, PCI_BRIDGE_CONTROL_REG);
    899 		cmd &= PCI_BRIDGE_CONTROL_MASK;
    900 		cmd |= (PCI_BRIDGE_CONTROL_PERE | PCI_BRIDGE_CONTROL_SERR)
    901 		    << PCI_BRIDGE_CONTROL_SHIFT;
    902 		if (pb->fast_b2b) {
    903 			cmd |= PCI_BRIDGE_CONTROL_SECFASTB2B
    904 			    << PCI_BRIDGE_CONTROL_SHIFT;
    905 		}
    906 		pci_conf_write(pd->pc, pd->tag, PCI_BRIDGE_CONTROL_REG, cmd);
    907 		cmd = pci_conf_read(pd->pc, pd->tag, PCI_COMMAND_STATUS_REG);
    908 		cmd |= PCI_COMMAND_IO_ENABLE | PCI_COMMAND_MEM_ENABLE;
    909 		pci_conf_write(pd->pc, pd->tag, PCI_COMMAND_STATUS_REG, cmd);
    910 	}
    911 
    912 	return rv;
    913 }
    914 
    915 /*
    916  * Calculate latency values, allocate I/O and MEM segments, then set them
    917  * up.  If a PCI-PCI bridge is found, configure the bridge separately,
    918  * which will cause a recursive call back here.
    919  */
    920 static int
    921 configure_bus(pciconf_bus_t *pb)
    922 {
    923 	pciconf_dev_t	*pd;
    924 	int		def_ltim, max_ltim, band, bus_mhz;
    925 
    926 	bus_mhz = pb->freq_66 ? 66 : 33;
    927 	max_ltim = pb->max_mingnt * bus_mhz / 4;	/* cvt to cycle count */
    928 	band = 40000000;			/* 0.25us cycles/sec */
    929 	if (band < pb->bandwidth_used) {
    930 		printf("PCI bus %d: Warning: Total bandwidth exceeded!?\n",
    931 		    pb->busno);
    932 		def_ltim = -1;
    933 	} else {
    934 		def_ltim = (band - pb->bandwidth_used) / pb->ndevs;
    935 		if (def_ltim > pb->min_maxlat)
    936 			def_ltim = pb->min_maxlat;
    937 		def_ltim = def_ltim * bus_mhz / 4;
    938 	}
    939 	def_ltim = (def_ltim + 7) & ~7;
    940 	max_ltim = (max_ltim + 7) & ~7;
    941 
    942 	pb->def_ltim = MIN( def_ltim, 255 );
    943 	pb->max_ltim = MIN( MAX(max_ltim, def_ltim ), 255 );
    944 
    945 	/*
    946 	 * Now we have what we need to initialize the devices.
    947 	 * It would probably be better if we could allocate all of these
    948 	 * for all busses at once, but "not right now".  First, get a list
    949 	 * of free memory ranges from the m.d. system.
    950 	 */
    951 	if (setup_iowins(pb) || setup_memwins(pb)) {
    952 		printf("PCI bus configuration failed: ");
    953 		printf("unable to assign all I/O and memory ranges.");
    954 		return -1;
    955 	}
    956 
    957 	/*
    958 	 * Configure the latency for the devices, and enable them.
    959 	 */
    960 	for (pd=pb->device ; pd < &pb->device[pb->ndevs] ; pd++) {
    961 		pcireg_t cmd, class, misc;
    962 		int	ltim;
    963 
    964 		if (pci_conf_debug) {
    965 			print_tag(pd->pc, pd->tag);
    966 			printf("Configuring device.\n");
    967 		}
    968 		class = pci_conf_read(pd->pc, pd->tag, PCI_CLASS_REG);
    969 		misc = pci_conf_read(pd->pc, pd->tag, PCI_BHLC_REG);
    970 		cmd = pci_conf_read(pd->pc, pd->tag, PCI_COMMAND_STATUS_REG);
    971 		cmd |= PCI_COMMAND_SERR_ENABLE | PCI_COMMAND_PARITY_ENABLE;
    972 		if (pb->fast_b2b)
    973 			cmd |= PCI_COMMAND_BACKTOBACK_ENABLE;
    974 		if (PCI_CLASS(class) != PCI_CLASS_BRIDGE ||
    975 		    PCI_SUBCLASS(class) != PCI_SUBCLASS_BRIDGE_PCI) {
    976 			if (pd->enable & PCI_CONF_ENABLE_IO)
    977 				cmd |= PCI_COMMAND_IO_ENABLE;
    978 			if (pd->enable & PCI_CONF_ENABLE_MEM)
    979 				cmd |= PCI_COMMAND_MEM_ENABLE;
    980 			if (pd->enable & PCI_CONF_ENABLE_BM)
    981 				cmd |= PCI_COMMAND_MASTER_ENABLE;
    982 			ltim = pd->min_gnt * bus_mhz / 4;
    983 			ltim = MIN (MAX (pb->def_ltim, ltim), pb->max_ltim);
    984 		} else {
    985 			cmd |= PCI_COMMAND_MASTER_ENABLE;
    986 			ltim = MIN (pb->def_ltim, pb->max_ltim);
    987 		}
    988 		if (!(pd->enable)) {
    989 			print_tag(pd->pc, pd->tag);
    990 			printf("Disabled due to lack of resources.\n");
    991 			cmd &= ~(PCI_COMMAND_MASTER_ENABLE |
    992 			    PCI_COMMAND_IO_ENABLE | PCI_COMMAND_MEM_ENABLE);
    993 		}
    994 		pci_conf_write(pd->pc, pd->tag, PCI_COMMAND_STATUS_REG, cmd);
    995 
    996 		misc &= ~((PCI_LATTIMER_MASK << PCI_LATTIMER_SHIFT) |
    997 		    (PCI_CACHELINE_MASK << PCI_CACHELINE_SHIFT));
    998 		misc |= (ltim & PCI_LATTIMER_MASK) << PCI_LATTIMER_SHIFT;
    999 		misc |= ((pb->cacheline_size >> 2) & PCI_CACHELINE_MASK) <<
   1000 		    PCI_CACHELINE_SHIFT;
   1001 		pci_conf_write(pd->pc, pd->tag, PCI_BHLC_REG, misc);
   1002 
   1003 		if (pd->ppb) {
   1004 			if (configure_bridge(pd) < 0)
   1005 				return -1;
   1006 			continue;
   1007 		}
   1008 	}
   1009 
   1010 	if (pci_conf_debug) {
   1011 		printf("PCI bus %d configured\n", pb->busno);
   1012 	}
   1013 
   1014 	return 0;
   1015 }
   1016 
   1017 /*
   1018  * Let's configure the PCI bus.
   1019  * This consists of basically scanning for all existing devices,
   1020  * identifying their needs, and then making another pass over them
   1021  * to set:
   1022  *	1. I/O addresses
   1023  *	2. Memory addresses (Prefetchable and not)
   1024  *	3. PCI command register
   1025  *	4. The latency part of the PCI BHLC (BIST (Built-In Self Test),
   1026  *	    Header type, Latency timer, Cache line size) register
   1027  *
   1028  * The command register is set to enable fast back-to-back transactions
   1029  * if the host bridge says it can handle it.  We also configure
   1030  * Master Enable, SERR enable, parity enable, and (if this is not a
   1031  * PCI-PCI bridge) the I/O and Memory spaces.  Apparently some devices
   1032  * will not report some I/O space.
   1033  *
   1034  * The latency is computed to be a "fair share" of the bus bandwidth.
   1035  * The bus bandwidth variable is initialized to the number of PCI cycles
   1036  * in one second.  The number of cycles taken for one transaction by each
   1037  * device (MAX_LAT + MIN_GNT) is then subtracted from the bandwidth.
   1038  * Care is taken to ensure that the latency timer won't be set such that
   1039  * it would exceed the critical time for any device.
   1040  *
   1041  * This is complicated somewhat due to the presence of bridges.  PCI-PCI
   1042  * bridges are probed and configured recursively.
   1043  */
   1044 int
   1045 pci_configure_bus(pci_chipset_tag_t pc, struct extent *ioext,
   1046     struct extent *memext, struct extent *pmemext, int firstbus,
   1047     int cacheline_size)
   1048 {
   1049 	pciconf_bus_t	*pb;
   1050 	int		rv;
   1051 
   1052 	pb = malloc (sizeof (pciconf_bus_t), M_DEVBUF, M_NOWAIT);
   1053 	pb->busno = firstbus;
   1054 	pb->next_busno = pb->busno + 1;
   1055 	pb->last_busno = 255;
   1056 	pb->cacheline_size = cacheline_size;
   1057 	pb->parent_bus = NULL;
   1058 	pb->swiz = 0;
   1059 	pb->io_32bit = 1;
   1060 	pb->pmem_64bit = 0;
   1061 	pb->ioext = ioext;
   1062 	pb->memext = memext;
   1063 	if (pmemext == NULL) {
   1064 		pb->pmemext = memext;
   1065 	} else {
   1066 		pb->pmemext = pmemext;
   1067 	}
   1068 	pb->pc = pc;
   1069 	pb->io_total = pb->mem_total = pb->pmem_total = 0;
   1070 
   1071 	rv = probe_bus(pb);
   1072 	pb->last_busno = pb->next_busno-1;
   1073 	if (rv == 0) {
   1074 		rv = configure_bus(pb);
   1075 	}
   1076 
   1077 	/*
   1078 	 * All done!
   1079 	 */
   1080 	free(pb, M_DEVBUF);
   1081 	return rv;
   1082 }
   1083