xref: /freebsd/sys/i386/pci/pci_cfgreg.c (revision 9a14aa017b21c292740c00ee098195cd46642730)
1 /*-
2  * Copyright (c) 1997, Stefan Esser <se@freebsd.org>
3  * Copyright (c) 2000, Michael Smith <msmith@freebsd.org>
4  * Copyright (c) 2000, BSDi
5  * Copyright (c) 2004, Scott Long <scottl@freebsd.org>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice unmodified, this list of conditions, and the following
13  *    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  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include "opt_xbox.h"
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/bus.h>
38 #include <sys/lock.h>
39 #include <sys/kernel.h>
40 #include <sys/mutex.h>
41 #include <sys/malloc.h>
42 #include <sys/queue.h>
43 #include <sys/sysctl.h>
44 #include <dev/pci/pcivar.h>
45 #include <dev/pci/pcireg.h>
46 #include <machine/pci_cfgreg.h>
47 #include <machine/pc/bios.h>
48 
49 #include <vm/vm.h>
50 #include <vm/vm_param.h>
51 #include <vm/vm_kern.h>
52 #include <vm/vm_extern.h>
53 #include <vm/pmap.h>
54 #include <machine/pmap.h>
55 
56 #ifdef XBOX
57 #include <machine/xbox.h>
58 #endif
59 
60 #define PRVERB(a) do {							\
61 	if (bootverbose)						\
62 		printf a ;						\
63 } while(0)
64 
65 #define PCIE_CACHE 8
66 struct pcie_cfg_elem {
67 	TAILQ_ENTRY(pcie_cfg_elem)	elem;
68 	vm_offset_t	vapage;
69 	vm_paddr_t	papage;
70 };
71 
72 enum {
73 	CFGMECH_NONE = 0,
74 	CFGMECH_1,
75 	CFGMECH_2,
76 	CFGMECH_PCIE,
77 };
78 
79 SYSCTL_DECL(_hw_pci);
80 
81 static TAILQ_HEAD(pcie_cfg_list, pcie_cfg_elem) pcie_list[MAXCPU];
82 static uint64_t pcie_base;
83 static int pcie_minbus, pcie_maxbus;
84 static uint32_t pcie_badslots;
85 static int cfgmech;
86 static int devmax;
87 static struct mtx pcicfg_mtx;
88 static int mcfg_enable = 1;
89 TUNABLE_INT("hw.pci.mcfg", &mcfg_enable);
90 SYSCTL_INT(_hw_pci, OID_AUTO, mcfg, CTLFLAG_RDTUN, &mcfg_enable, 0,
91     "Enable support for PCI-e memory mapped config access");
92 
93 static uint32_t	pci_docfgregread(int bus, int slot, int func, int reg,
94 		    int bytes);
95 static int	pcireg_cfgread(int bus, int slot, int func, int reg, int bytes);
96 static void	pcireg_cfgwrite(int bus, int slot, int func, int reg, int data, int bytes);
97 #ifndef XEN
98 static int	pcireg_cfgopen(void);
99 #endif
100 static int	pciereg_cfgread(int bus, unsigned slot, unsigned func,
101 		    unsigned reg, unsigned bytes);
102 static void	pciereg_cfgwrite(int bus, unsigned slot, unsigned func,
103 		    unsigned reg, int data, unsigned bytes);
104 
105 /*
106  * Some BIOS writers seem to want to ignore the spec and put
107  * 0 in the intline rather than 255 to indicate none.  Some use
108  * numbers in the range 128-254 to indicate something strange and
109  * apparently undocumented anywhere.  Assume these are completely bogus
110  * and map them to 255, which means "none".
111  */
112 static __inline int
113 pci_i386_map_intline(int line)
114 {
115 	if (line == 0 || line >= 128)
116 		return (PCI_INVALID_IRQ);
117 	return (line);
118 }
119 
120 #ifndef XEN
121 static u_int16_t
122 pcibios_get_version(void)
123 {
124 	struct bios_regs args;
125 
126 	if (PCIbios.ventry == 0) {
127 		PRVERB(("pcibios: No call entry point\n"));
128 		return (0);
129 	}
130 	args.eax = PCIBIOS_BIOS_PRESENT;
131 	if (bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL))) {
132 		PRVERB(("pcibios: BIOS_PRESENT call failed\n"));
133 		return (0);
134 	}
135 	if (args.edx != 0x20494350) {
136 		PRVERB(("pcibios: BIOS_PRESENT didn't return 'PCI ' in edx\n"));
137 		return (0);
138 	}
139 	return (args.ebx & 0xffff);
140 }
141 #endif
142 
143 /*
144  * Initialise access to PCI configuration space
145  */
146 int
147 pci_cfgregopen(void)
148 {
149 #ifdef XEN
150 	return (0);
151 #else
152 	static int		opened = 0;
153 	uint64_t		pciebar;
154 	u_int16_t		vid, did;
155 	u_int16_t		v;
156 
157 	if (opened)
158 		return (1);
159 
160 	if (cfgmech == CFGMECH_NONE && pcireg_cfgopen() == 0)
161 		return (0);
162 
163 	v = pcibios_get_version();
164 	if (v > 0)
165 		PRVERB(("pcibios: BIOS version %x.%02x\n", (v & 0xff00) >> 8,
166 		    v & 0xff));
167 	mtx_init(&pcicfg_mtx, "pcicfg", NULL, MTX_SPIN);
168 	opened = 1;
169 
170 	/* $PIR requires PCI BIOS 2.10 or greater. */
171 	if (v >= 0x0210)
172 		pci_pir_open();
173 
174 	if (cfgmech == CFGMECH_PCIE)
175 		return (1);
176 
177 	/*
178 	 * Grope around in the PCI config space to see if this is a
179 	 * chipset that is capable of doing memory-mapped config cycles.
180 	 * This also implies that it can do PCIe extended config cycles.
181 	 */
182 
183 	/* Check for supported chipsets */
184 	vid = pci_cfgregread(0, 0, 0, PCIR_VENDOR, 2);
185 	did = pci_cfgregread(0, 0, 0, PCIR_DEVICE, 2);
186 	switch (vid) {
187 	case 0x8086:
188 		switch (did) {
189 		case 0x3590:
190 		case 0x3592:
191 			/* Intel 7520 or 7320 */
192 			pciebar = pci_cfgregread(0, 0, 0, 0xce, 2) << 16;
193 			pcie_cfgregopen(pciebar, 0, 255);
194 			break;
195 		case 0x2580:
196 		case 0x2584:
197 		case 0x2590:
198 			/* Intel 915, 925, or 915GM */
199 			pciebar = pci_cfgregread(0, 0, 0, 0x48, 4);
200 			pcie_cfgregopen(pciebar, 0, 255);
201 			break;
202 		}
203 	}
204 
205 	return(1);
206 #endif
207 }
208 
209 static uint32_t
210 pci_docfgregread(int bus, int slot, int func, int reg, int bytes)
211 {
212 
213 	if (cfgmech == CFGMECH_PCIE &&
214 	    (bus >= pcie_minbus && bus <= pcie_maxbus) &&
215 	    (bus != 0 || !(1 << slot & pcie_badslots)))
216 		return (pciereg_cfgread(bus, slot, func, reg, bytes));
217 	else
218 		return (pcireg_cfgread(bus, slot, func, reg, bytes));
219 }
220 
221 /*
222  * Read configuration space register
223  */
224 u_int32_t
225 pci_cfgregread(int bus, int slot, int func, int reg, int bytes)
226 {
227 	uint32_t line;
228 
229 	/*
230 	 * Some BIOS writers seem to want to ignore the spec and put
231 	 * 0 in the intline rather than 255 to indicate none.  The rest of
232 	 * the code uses 255 as an invalid IRQ.
233 	 */
234 	if (reg == PCIR_INTLINE && bytes == 1) {
235 		line = pci_docfgregread(bus, slot, func, PCIR_INTLINE, 1);
236 		return (pci_i386_map_intline(line));
237 	}
238 	return (pci_docfgregread(bus, slot, func, reg, bytes));
239 }
240 
241 /*
242  * Write configuration space register
243  */
244 void
245 pci_cfgregwrite(int bus, int slot, int func, int reg, u_int32_t data, int bytes)
246 {
247 
248 	if (cfgmech == CFGMECH_PCIE &&
249 	    (bus >= pcie_minbus && bus <= pcie_maxbus) &&
250 	    (bus != 0 || !(1 << slot & pcie_badslots)))
251 		pciereg_cfgwrite(bus, slot, func, reg, data, bytes);
252 	else
253 		pcireg_cfgwrite(bus, slot, func, reg, data, bytes);
254 }
255 
256 /*
257  * Configuration space access using direct register operations
258  */
259 
260 /* enable configuration space accesses and return data port address */
261 static int
262 pci_cfgenable(unsigned bus, unsigned slot, unsigned func, int reg, int bytes)
263 {
264 	int dataport = 0;
265 
266 #ifdef XBOX
267 	if (arch_i386_is_xbox) {
268 		/*
269 		 * The Xbox MCPX chipset is a derivative of the nForce 1
270 		 * chipset. It almost has the same bus layout; some devices
271 		 * cannot be used, because they have been removed.
272 		 */
273 
274 		/*
275 		 * Devices 00:00.1 and 00:00.2 used to be memory controllers on
276 		 * the nForce chipset, but on the Xbox, using them will lockup
277 		 * the chipset.
278 		 */
279 		if (bus == 0 && slot == 0 && (func == 1 || func == 2))
280 			return dataport;
281 
282 		/*
283 		 * Bus 1 only contains a VGA controller at 01:00.0. When you try
284 		 * to probe beyond that device, you only get garbage, which
285 		 * could cause lockups.
286 		 */
287 		if (bus == 1 && (slot != 0 || func != 0))
288 			return dataport;
289 
290 		/*
291 		 * Bus 2 used to contain the AGP controller, but the Xbox MCPX
292 		 * doesn't have one. Probing it can cause lockups.
293 		 */
294 		if (bus >= 2)
295 			return dataport;
296 	}
297 #endif
298 
299 	if (bus <= PCI_BUSMAX
300 	    && slot < devmax
301 	    && func <= PCI_FUNCMAX
302 	    && (unsigned)reg <= PCI_REGMAX
303 	    && bytes != 3
304 	    && (unsigned)bytes <= 4
305 	    && (reg & (bytes - 1)) == 0) {
306 		switch (cfgmech) {
307 		case CFGMECH_PCIE:
308 		case CFGMECH_1:
309 			outl(CONF1_ADDR_PORT, (1 << 31)
310 			    | (bus << 16) | (slot << 11)
311 			    | (func << 8) | (reg & ~0x03));
312 			dataport = CONF1_DATA_PORT + (reg & 0x03);
313 			break;
314 		case CFGMECH_2:
315 			outb(CONF2_ENABLE_PORT, 0xf0 | (func << 1));
316 			outb(CONF2_FORWARD_PORT, bus);
317 			dataport = 0xc000 | (slot << 8) | reg;
318 			break;
319 		}
320 	}
321 	return (dataport);
322 }
323 
324 /* disable configuration space accesses */
325 static void
326 pci_cfgdisable(void)
327 {
328 	switch (cfgmech) {
329 	case CFGMECH_PCIE:
330 	case CFGMECH_1:
331 		/*
332 		 * Do nothing for the config mechanism 1 case.
333 		 * Writing a 0 to the address port can apparently
334 		 * confuse some bridges and cause spurious
335 		 * access failures.
336 		 */
337 		break;
338 	case CFGMECH_2:
339 		outb(CONF2_ENABLE_PORT, 0);
340 		break;
341 	}
342 }
343 
344 static int
345 pcireg_cfgread(int bus, int slot, int func, int reg, int bytes)
346 {
347 	int data = -1;
348 	int port;
349 
350 	mtx_lock_spin(&pcicfg_mtx);
351 	port = pci_cfgenable(bus, slot, func, reg, bytes);
352 	if (port != 0) {
353 		switch (bytes) {
354 		case 1:
355 			data = inb(port);
356 			break;
357 		case 2:
358 			data = inw(port);
359 			break;
360 		case 4:
361 			data = inl(port);
362 			break;
363 		}
364 		pci_cfgdisable();
365 	}
366 	mtx_unlock_spin(&pcicfg_mtx);
367 	return (data);
368 }
369 
370 static void
371 pcireg_cfgwrite(int bus, int slot, int func, int reg, int data, int bytes)
372 {
373 	int port;
374 
375 	mtx_lock_spin(&pcicfg_mtx);
376 	port = pci_cfgenable(bus, slot, func, reg, bytes);
377 	if (port != 0) {
378 		switch (bytes) {
379 		case 1:
380 			outb(port, data);
381 			break;
382 		case 2:
383 			outw(port, data);
384 			break;
385 		case 4:
386 			outl(port, data);
387 			break;
388 		}
389 		pci_cfgdisable();
390 	}
391 	mtx_unlock_spin(&pcicfg_mtx);
392 }
393 
394 #ifndef XEN
395 /* check whether the configuration mechanism has been correctly identified */
396 static int
397 pci_cfgcheck(int maxdev)
398 {
399 	uint32_t id, class;
400 	uint8_t header;
401 	uint8_t device;
402 	int port;
403 
404 	if (bootverbose)
405 		printf("pci_cfgcheck:\tdevice ");
406 
407 	for (device = 0; device < maxdev; device++) {
408 		if (bootverbose)
409 			printf("%d ", device);
410 
411 		port = pci_cfgenable(0, device, 0, 0, 4);
412 		id = inl(port);
413 		if (id == 0 || id == 0xffffffff)
414 			continue;
415 
416 		port = pci_cfgenable(0, device, 0, 8, 4);
417 		class = inl(port) >> 8;
418 		if (bootverbose)
419 			printf("[class=%06x] ", class);
420 		if (class == 0 || (class & 0xf870ff) != 0)
421 			continue;
422 
423 		port = pci_cfgenable(0, device, 0, 14, 1);
424 		header = inb(port);
425 		if (bootverbose)
426 			printf("[hdr=%02x] ", header);
427 		if ((header & 0x7e) != 0)
428 			continue;
429 
430 		if (bootverbose)
431 			printf("is there (id=%08x)\n", id);
432 
433 		pci_cfgdisable();
434 		return (1);
435 	}
436 	if (bootverbose)
437 		printf("-- nothing found\n");
438 
439 	pci_cfgdisable();
440 	return (0);
441 }
442 
443 static int
444 pcireg_cfgopen(void)
445 {
446 	uint32_t mode1res, oldval1;
447 	uint8_t mode2res, oldval2;
448 
449 	/* Check for type #1 first. */
450 	oldval1 = inl(CONF1_ADDR_PORT);
451 
452 	if (bootverbose) {
453 		printf("pci_open(1):\tmode 1 addr port (0x0cf8) is 0x%08x\n",
454 		    oldval1);
455 	}
456 
457 	cfgmech = CFGMECH_1;
458 	devmax = 32;
459 
460 	outl(CONF1_ADDR_PORT, CONF1_ENABLE_CHK);
461 	DELAY(1);
462 	mode1res = inl(CONF1_ADDR_PORT);
463 	outl(CONF1_ADDR_PORT, oldval1);
464 
465 	if (bootverbose)
466 		printf("pci_open(1a):\tmode1res=0x%08x (0x%08lx)\n",  mode1res,
467 		    CONF1_ENABLE_CHK);
468 
469 	if (mode1res) {
470 		if (pci_cfgcheck(32))
471 			return (cfgmech);
472 	}
473 
474 	outl(CONF1_ADDR_PORT, CONF1_ENABLE_CHK1);
475 	mode1res = inl(CONF1_ADDR_PORT);
476 	outl(CONF1_ADDR_PORT, oldval1);
477 
478 	if (bootverbose)
479 		printf("pci_open(1b):\tmode1res=0x%08x (0x%08lx)\n",  mode1res,
480 		    CONF1_ENABLE_CHK1);
481 
482 	if ((mode1res & CONF1_ENABLE_MSK1) == CONF1_ENABLE_RES1) {
483 		if (pci_cfgcheck(32))
484 			return (cfgmech);
485 	}
486 
487 	/* Type #1 didn't work, so try type #2. */
488 	oldval2 = inb(CONF2_ENABLE_PORT);
489 
490 	if (bootverbose) {
491 		printf("pci_open(2):\tmode 2 enable port (0x0cf8) is 0x%02x\n",
492 		    oldval2);
493 	}
494 
495 	if ((oldval2 & 0xf0) == 0) {
496 
497 		cfgmech = CFGMECH_2;
498 		devmax = 16;
499 
500 		outb(CONF2_ENABLE_PORT, CONF2_ENABLE_CHK);
501 		mode2res = inb(CONF2_ENABLE_PORT);
502 		outb(CONF2_ENABLE_PORT, oldval2);
503 
504 		if (bootverbose)
505 			printf("pci_open(2a):\tmode2res=0x%02x (0x%02x)\n",
506 			    mode2res, CONF2_ENABLE_CHK);
507 
508 		if (mode2res == CONF2_ENABLE_RES) {
509 			if (bootverbose)
510 				printf("pci_open(2a):\tnow trying mechanism 2\n");
511 
512 			if (pci_cfgcheck(16))
513 				return (cfgmech);
514 		}
515 	}
516 
517 	/* Nothing worked, so punt. */
518 	cfgmech = CFGMECH_NONE;
519 	devmax = 0;
520 	return (cfgmech);
521 }
522 
523 int
524 pcie_cfgregopen(uint64_t base, uint8_t minbus, uint8_t maxbus)
525 {
526 	struct pcie_cfg_list *pcielist;
527 	struct pcie_cfg_elem *pcie_array, *elem;
528 #ifdef SMP
529 	struct pcpu *pc;
530 #endif
531 	vm_offset_t va;
532 	uint32_t val1, val2;
533 	int i, slot;
534 
535 	if (!mcfg_enable)
536 		return (0);
537 
538 	if (minbus != 0)
539 		return (0);
540 
541 #ifndef PAE
542 	if (base >= 0x100000000) {
543 		if (bootverbose)
544 			printf(
545 	    "PCI: Memory Mapped PCI configuration area base 0x%jx too high\n",
546 			    (uintmax_t)base);
547 		return (0);
548 	}
549 #endif
550 
551 	if (bootverbose)
552 		printf("PCIe: Memory Mapped configuration base @ 0x%jx\n",
553 		    (uintmax_t)base);
554 
555 #ifdef SMP
556 	STAILQ_FOREACH(pc, &cpuhead, pc_allcpu)
557 #endif
558 	{
559 
560 		pcie_array = malloc(sizeof(struct pcie_cfg_elem) * PCIE_CACHE,
561 		    M_DEVBUF, M_NOWAIT);
562 		if (pcie_array == NULL)
563 			return (0);
564 
565 		va = kmem_alloc_nofault(kernel_map, PCIE_CACHE * PAGE_SIZE);
566 		if (va == 0) {
567 			free(pcie_array, M_DEVBUF);
568 			return (0);
569 		}
570 
571 #ifdef SMP
572 		pcielist = &pcie_list[pc->pc_cpuid];
573 #else
574 		pcielist = &pcie_list[0];
575 #endif
576 		TAILQ_INIT(pcielist);
577 		for (i = 0; i < PCIE_CACHE; i++) {
578 			elem = &pcie_array[i];
579 			elem->vapage = va + (i * PAGE_SIZE);
580 			elem->papage = 0;
581 			TAILQ_INSERT_HEAD(pcielist, elem, elem);
582 		}
583 	}
584 
585 	pcie_base = base;
586 	pcie_minbus = minbus;
587 	pcie_maxbus = maxbus;
588 	cfgmech = CFGMECH_PCIE;
589 	devmax = 32;
590 
591 	/*
592 	 * On some AMD systems, some of the devices on bus 0 are
593 	 * inaccessible using memory-mapped PCI config access.  Walk
594 	 * bus 0 looking for such devices.  For these devices, we will
595 	 * fall back to using type 1 config access instead.
596 	 */
597 	if (pci_cfgregopen() != 0) {
598 		for (slot = 0; slot <= PCI_SLOTMAX; slot++) {
599 			val1 = pcireg_cfgread(0, slot, 0, 0, 4);
600 			if (val1 == 0xffffffff)
601 				continue;
602 
603 			val2 = pciereg_cfgread(0, slot, 0, 0, 4);
604 			if (val2 != val1)
605 				pcie_badslots |= (1 << slot);
606 		}
607 	}
608 
609 	return (1);
610 }
611 #endif /* !XEN */
612 
613 #define PCIE_PADDR(bar, reg, bus, slot, func)	\
614 	((bar)				|	\
615 	(((bus) & 0xff) << 20)		|	\
616 	(((slot) & 0x1f) << 15)		|	\
617 	(((func) & 0x7) << 12)		|	\
618 	((reg) & 0xfff))
619 
620 /*
621  * Find an element in the cache that matches the physical page desired, or
622  * create a new mapping from the least recently used element.
623  * A very simple LRU algorithm is used here, does it need to be more
624  * efficient?
625  */
626 static __inline struct pcie_cfg_elem *
627 pciereg_findelem(vm_paddr_t papage)
628 {
629 	struct pcie_cfg_list *pcielist;
630 	struct pcie_cfg_elem *elem;
631 
632 	pcielist = &pcie_list[PCPU_GET(cpuid)];
633 	TAILQ_FOREACH(elem, pcielist, elem) {
634 		if (elem->papage == papage)
635 			break;
636 	}
637 
638 	if (elem == NULL) {
639 		elem = TAILQ_LAST(pcielist, pcie_cfg_list);
640 		if (elem->papage != 0) {
641 			pmap_kremove(elem->vapage);
642 			invlpg(elem->vapage);
643 		}
644 		pmap_kenter(elem->vapage, papage);
645 		elem->papage = papage;
646 	}
647 
648 	if (elem != TAILQ_FIRST(pcielist)) {
649 		TAILQ_REMOVE(pcielist, elem, elem);
650 		TAILQ_INSERT_HEAD(pcielist, elem, elem);
651 	}
652 	return (elem);
653 }
654 
655 static int
656 pciereg_cfgread(int bus, unsigned slot, unsigned func, unsigned reg,
657     unsigned bytes)
658 {
659 	struct pcie_cfg_elem *elem;
660 	volatile vm_offset_t va;
661 	vm_paddr_t pa, papage;
662 	int data = -1;
663 
664 	if (bus < pcie_minbus || bus > pcie_maxbus || slot > PCI_SLOTMAX ||
665 	    func > PCI_FUNCMAX || reg > PCIE_REGMAX)
666 		return (-1);
667 
668 	critical_enter();
669 	pa = PCIE_PADDR(pcie_base, reg, bus, slot, func);
670 	papage = pa & ~PAGE_MASK;
671 	elem = pciereg_findelem(papage);
672 	va = elem->vapage | (pa & PAGE_MASK);
673 
674 	switch (bytes) {
675 	case 4:
676 		data = *(volatile uint32_t *)(va);
677 		break;
678 	case 2:
679 		data = *(volatile uint16_t *)(va);
680 		break;
681 	case 1:
682 		data = *(volatile uint8_t *)(va);
683 		break;
684 	}
685 
686 	critical_exit();
687 	return (data);
688 }
689 
690 static void
691 pciereg_cfgwrite(int bus, unsigned slot, unsigned func, unsigned reg, int data,
692     unsigned bytes)
693 {
694 	struct pcie_cfg_elem *elem;
695 	volatile vm_offset_t va;
696 	vm_paddr_t pa, papage;
697 
698 	if (bus < pcie_minbus || bus > pcie_maxbus || slot > PCI_SLOTMAX ||
699 	    func > PCI_FUNCMAX || reg > PCIE_REGMAX)
700 		return;
701 
702 	critical_enter();
703 	pa = PCIE_PADDR(pcie_base, reg, bus, slot, func);
704 	papage = pa & ~PAGE_MASK;
705 	elem = pciereg_findelem(papage);
706 	va = elem->vapage | (pa & PAGE_MASK);
707 
708 	switch (bytes) {
709 	case 4:
710 		*(volatile uint32_t *)(va) = data;
711 		break;
712 	case 2:
713 		*(volatile uint16_t *)(va) = data;
714 		break;
715 	case 1:
716 		*(volatile uint8_t *)(va) = data;
717 		break;
718 	}
719 
720 	critical_exit();
721 }
722