xref: /freebsd/sys/i386/pci/pci_cfgreg.c (revision d086ded32300bc0f33fb1574d0bcfccfbc60881d)
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  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice unmodified, this list of conditions, and the following
12  *    disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>		/* XXX trim includes */
33 #include <sys/systm.h>
34 #include <sys/bus.h>
35 #include <sys/kernel.h>
36 #include <sys/module.h>
37 #include <sys/malloc.h>
38 #include <sys/lock.h>
39 #include <sys/mutex.h>
40 #include <vm/vm.h>
41 #include <vm/pmap.h>
42 #include <machine/md_var.h>
43 #include <dev/pci/pcivar.h>
44 #include <dev/pci/pcireg.h>
45 #include <isa/isavar.h>
46 #include <machine/pci_cfgreg.h>
47 #include <machine/segments.h>
48 #include <machine/pc/bios.h>
49 
50 #ifdef APIC_IO
51 #include <machine/smp.h>
52 #endif /* APIC_IO */
53 
54 #include "pcib_if.h"
55 
56 #define PRVERB(a) do {							\
57 	if (bootverbose)						\
58 		printf a ;						\
59 } while(0)
60 
61 static int cfgmech;
62 static int devmax;
63 
64 static int	pci_cfgintr_valid(struct PIR_entry *pe, int pin, int irq);
65 static int	pci_cfgintr_unique(struct PIR_entry *pe, int pin);
66 static int	pci_cfgintr_linked(struct PIR_entry *pe, int pin);
67 static int	pci_cfgintr_search(struct PIR_entry *pe, int bus, int device, int matchpin, int pin);
68 static int	pci_cfgintr_virgin(struct PIR_entry *pe, int pin);
69 
70 static void	pci_print_irqmask(u_int16_t irqs);
71 static void	pci_print_route_table(struct PIR_table *prt, int size);
72 static int	pcireg_cfgread(int bus, int slot, int func, int reg, int bytes);
73 static void	pcireg_cfgwrite(int bus, int slot, int func, int reg, int data, int bytes);
74 static int	pcireg_cfgopen(void);
75 
76 static struct PIR_table *pci_route_table;
77 static int pci_route_count;
78 
79 static struct mtx pcicfg_mtx;
80 
81 /*
82  * Some BIOS writers seem to want to ignore the spec and put
83  * 0 in the intline rather than 255 to indicate none.  Some use
84  * numbers in the range 128-254 to indicate something strange and
85  * apparently undocumented anywhere.  Assume these are completely bogus
86  * and map them to 255, which means "none".
87  */
88 static __inline__ int
89 pci_i386_map_intline(int line)
90 {
91 	if (line == 0 || line >= 128)
92 		return (PCI_INVALID_IRQ);
93 	return (line);
94 }
95 
96 static u_int16_t
97 pcibios_get_version(void)
98 {
99 	struct bios_regs args;
100 
101 	if (PCIbios.ventry == 0) {
102 		PRVERB(("pcibios: No call entry point\n"));
103 		return (0);
104 	}
105 	args.eax = PCIBIOS_BIOS_PRESENT;
106 	if (bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL))) {
107 		PRVERB(("pcibios: BIOS_PRESENT call failed\n"));
108 		return (0);
109 	}
110 	if (args.edx != 0x20494350) {
111 		PRVERB(("pcibios: BIOS_PRESENT didn't return 'PCI ' in edx\n"));
112 		return (0);
113 	}
114 	return (args.ebx & 0xffff);
115 }
116 
117 /*
118  * Initialise access to PCI configuration space
119  */
120 int
121 pci_cfgregopen(void)
122 {
123 	static int		opened = 0;
124 	u_long			sigaddr;
125 	static struct PIR_table	*pt;
126 	u_int16_t		v;
127 	u_int8_t		ck, *cv;
128 	int			i;
129 
130 	if (opened)
131 		return(1);
132 
133 	if (pcireg_cfgopen() == 0)
134 		return(0);
135 
136 	v = pcibios_get_version();
137 	if (v > 0)
138 		printf("pcibios: BIOS version %x.%02x\n", (v & 0xff00) >> 8,
139 		    v & 0xff);
140 
141 	/*
142 	 * Look for the interrupt routing table.
143 	 *
144 	 * We use PCI BIOS's PIR table if it's available $PIR is the
145 	 * standard way to do this.  Sadly, some machines are not
146 	 * standards conforming and have _PIR instead.  We shrug and cope
147 	 * by looking for both.
148 	 */
149 	if (pcibios_get_version() >= 0x0210 && pt == NULL) {
150 		sigaddr = bios_sigsearch(0, "$PIR", 4, 16, 0);
151 		if (sigaddr == 0)
152 			sigaddr = bios_sigsearch(0, "_PIR", 4, 16, 0);
153 		if (sigaddr != 0) {
154 			pt = (struct PIR_table *)(uintptr_t)
155 			    BIOS_PADDRTOVADDR(sigaddr);
156 			for (cv = (u_int8_t *)pt, ck = 0, i = 0;
157 			     i < (pt->pt_header.ph_length); i++) {
158 				ck += cv[i];
159 			}
160 			if (ck == 0 && pt->pt_header.ph_length >
161 			    sizeof(struct PIR_header)) {
162 				pci_route_table = pt;
163 				pci_route_count = (pt->pt_header.ph_length -
164 				    sizeof(struct PIR_header)) /
165 				    sizeof(struct PIR_entry);
166 				printf("Using $PIR table, %d entries at %p\n",
167 				    pci_route_count, pci_route_table);
168 				if (bootverbose)
169 					pci_print_route_table(pci_route_table,
170 					    pci_route_count);
171 			}
172 		}
173 	}
174 	mtx_init(&pcicfg_mtx, "pcicfg", NULL, MTX_SPIN);
175 	opened = 1;
176 	return(1);
177 }
178 
179 /*
180  * Read configuration space register
181  */
182 u_int32_t
183 pci_cfgregread(int bus, int slot, int func, int reg, int bytes)
184 {
185 	uint32_t line;
186 #ifdef APIC_IO
187 	uint32_t pin;
188 
189 	/*
190 	 * If we are using the APIC, the contents of the intline
191 	 * register will probably be wrong (since they are set up for
192 	 * use with the PIC.  Rather than rewrite these registers
193 	 * (maybe that would be smarter) we trap attempts to read them
194 	 * and translate to our private vector numbers.
195 	 */
196 	if ((reg == PCIR_INTLINE) && (bytes == 1)) {
197 
198 		pin = pcireg_cfgread(bus, slot, func, PCIR_INTPIN, 1);
199 		line = pcireg_cfgread(bus, slot, func, PCIR_INTLINE, 1);
200 
201 		if (pin != 0) {
202 			int airq;
203 
204 			airq = pci_apic_irq(bus, slot, pin);
205 			if (airq >= 0) {
206 				/* PCI specific entry found in MP table */
207 				if (airq != line)
208 					undirect_pci_irq(line);
209 				return(airq);
210 			} else {
211 				/*
212 				 * PCI interrupts might be redirected
213 				 * to the ISA bus according to some MP
214 				 * tables. Use the same methods as
215 				 * used by the ISA devices devices to
216 				 * find the proper IOAPIC int pin.
217 				 */
218 				airq = isa_apic_irq(line);
219 				if ((airq >= 0) && (airq != line)) {
220 					/* XXX: undirect_pci_irq() ? */
221 					undirect_isa_irq(line);
222 					return(airq);
223 				}
224 			}
225 		}
226 		return(line);
227 	}
228 #else
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 = pcireg_cfgread(bus, slot, func, PCIR_INTLINE, 1);
236 		return pci_i386_map_intline(line);
237 	}
238 #endif /* APIC_IO */
239 	return(pcireg_cfgread(bus, slot, func, reg, bytes));
240 }
241 
242 /*
243  * Write configuration space register
244  */
245 void
246 pci_cfgregwrite(int bus, int slot, int func, int reg, u_int32_t data, int bytes)
247 {
248 
249 	pcireg_cfgwrite(bus, slot, func, reg, data, bytes);
250 }
251 
252 /*
253  * Route a PCI interrupt
254  */
255 int
256 pci_cfgintr(int bus, int device, int pin, int oldirq)
257 {
258 	struct PIR_entry	*pe;
259 	int			i, irq;
260 	struct bios_regs	args;
261 	u_int16_t		v;
262  	int already = 0;
263  	int errok = 0;
264 
265 	v = pcibios_get_version();
266 	if (v < 0x0210) {
267 		PRVERB((
268 		"pci_cfgintr: BIOS %x.%02x doesn't support interrupt routing\n",
269 		    (v & 0xff00) >> 8, v & 0xff));
270 		return (PCI_INVALID_IRQ);
271 	}
272 	if ((bus < 0) || (bus > 255) || (device < 0) || (device > 255) ||
273 	    (pin < 1) || (pin > 4))
274 		return(PCI_INVALID_IRQ);
275 
276 	/*
277 	 * Scan the entry table for a contender
278 	 */
279 	for (i = 0, pe = &pci_route_table->pt_entry[0]; i < pci_route_count;
280 	     i++, pe++) {
281 		if ((bus != pe->pe_bus) || (device != pe->pe_device))
282 			continue;
283 		/*
284 		 * A link of 0 means that this intpin is not connected to
285 		 * any other device's interrupt pins and is not connected to
286 		 * any of the Interrupt Router's interrupt pins, so we can't
287 		 * route it.
288 		 */
289 		if (pe->pe_intpin[pin - 1].link == 0)
290 			continue;
291 
292 		if (pci_cfgintr_valid(pe, pin, oldirq)) {
293 			printf("pci_cfgintr: %d:%d INT%c BIOS irq %d\n", bus,
294 			    device, 'A' + pin - 1, oldirq);
295 			return (oldirq);
296 		}
297 
298 		/*
299 		 * We try to find a linked interrupt, then we look to see
300 		 * if the interrupt is uniquely routed, then we look for
301 		 * a virgin interrupt.  The virgin interrupt should return
302 		 * an interrupt we can route, but if that fails, maybe we
303 		 * should try harder to route a different interrupt.
304 		 * However, experience has shown that that's rarely the
305 		 * failure mode we see.
306 		 */
307 		irq = pci_cfgintr_linked(pe, pin);
308 		if (irq != PCI_INVALID_IRQ)
309 			already = 1;
310 		if (irq == PCI_INVALID_IRQ) {
311 			irq = pci_cfgintr_unique(pe, pin);
312 			if (irq != PCI_INVALID_IRQ)
313 				errok = 1;
314 		}
315 		if (irq == PCI_INVALID_IRQ)
316 			irq = pci_cfgintr_virgin(pe, pin);
317 		if (irq == PCI_INVALID_IRQ)
318 			break;
319 
320 		/*
321 		 * Ask the BIOS to route the interrupt.  If we picked an
322 		 * interrupt that failed, we should really try other
323 		 * choices that the BIOS offers us.
324 		 *
325 		 * For uniquely routed interrupts, we need to try
326 		 * to route them on some machines.  Yet other machines
327 		 * fail to route, so we have to pretend that in that
328 		 * case it worked.  Isn't pc hardware fun?
329 		 *
330 		 * NOTE: if we want to whack hardware to do this, then
331 		 * I think the right way to do that would be to have
332 		 * bridge drivers that do this.  I'm not sure that the
333 		 * $PIR table would be valid for those interrupt
334 		 * routers.
335 		 */
336 		args.eax = PCIBIOS_ROUTE_INTERRUPT;
337 		args.ebx = (bus << 8) | (device << 3);
338 		/* pin value is 0xa - 0xd */
339 		args.ecx = (irq << 8) | (0xa + pin - 1);
340 		if (!already &&
341 		    bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL)) &&
342 		    !errok) {
343 			PRVERB(("pci_cfgintr: ROUTE_INTERRUPT failed.\n"));
344 			return(PCI_INVALID_IRQ);
345 		}
346 		printf("pci_cfgintr: %d:%d INT%c routed to irq %d\n", bus,
347 		    device, 'A' + pin - 1, irq);
348 		return(irq);
349 	}
350 
351 	PRVERB(("pci_cfgintr: can't route an interrupt to %d:%d INT%c\n", bus,
352 	    device, 'A' + pin - 1));
353 	return(PCI_INVALID_IRQ);
354 }
355 
356 /*
357  * Check to see if an existing IRQ setting is valid.
358  */
359 static int
360 pci_cfgintr_valid(struct PIR_entry *pe, int pin, int irq)
361 {
362 	uint32_t irqmask;
363 
364 	if (!PCI_INTERRUPT_VALID(irq))
365 		return (0);
366 	irqmask = pe->pe_intpin[pin - 1].irqs;
367 	if (irqmask & (1 << irq)) {
368 		PRVERB(("pci_cfgintr_valid: BIOS irq %d is valid\n", irq));
369 		return (1);
370 	}
371 	return (0);
372 }
373 
374 /*
375  * Look to see if the routing table claims this pin is uniquely routed.
376  */
377 static int
378 pci_cfgintr_unique(struct PIR_entry *pe, int pin)
379 {
380 	int		irq;
381 	uint32_t	irqmask;
382 
383 	irqmask = pe->pe_intpin[pin - 1].irqs;
384 	if (irqmask != 0 && powerof2(irqmask)) {
385 		irq = ffs(irqmask) - 1;
386 		PRVERB(("pci_cfgintr_unique: hard-routed to irq %d\n", irq));
387 		return(irq);
388 	}
389 	return(PCI_INVALID_IRQ);
390 }
391 
392 /*
393  * Look for another device which shares the same link byte and
394  * already has a unique IRQ, or which has had one routed already.
395  */
396 static int
397 pci_cfgintr_linked(struct PIR_entry *pe, int pin)
398 {
399 	struct PIR_entry	*oe;
400 	struct PIR_intpin	*pi;
401 	int			i, j, irq;
402 
403 	/*
404 	 * Scan table slots.
405 	 */
406 	for (i = 0, oe = &pci_route_table->pt_entry[0]; i < pci_route_count;
407 	     i++, oe++) {
408 		/* scan interrupt pins */
409 		for (j = 0, pi = &oe->pe_intpin[0]; j < 4; j++, pi++) {
410 
411 			/* don't look at the entry we're trying to match */
412 			if ((pe == oe) && (i == (pin - 1)))
413 				continue;
414 			/* compare link bytes */
415 			if (pi->link != pe->pe_intpin[pin - 1].link)
416 				continue;
417 			/* link destination mapped to a unique interrupt? */
418 			if (pi->irqs != 0 && powerof2(pi->irqs)) {
419 				irq = ffs(pi->irqs) - 1;
420 				PRVERB(("pci_cfgintr_linked: linked (%x) to hard-routed irq %d\n",
421 				    pi->link, irq));
422 				return(irq);
423 			}
424 
425 			/*
426 			 * look for the real PCI device that matches this
427 			 * table entry
428 			 */
429 			irq = pci_cfgintr_search(pe, oe->pe_bus, oe->pe_device,
430 			    j, pin);
431 			if (irq != PCI_INVALID_IRQ)
432 				return(irq);
433 		}
434 	}
435 	return(PCI_INVALID_IRQ);
436 }
437 
438 /*
439  * Scan for the real PCI device at (bus)/(device) using intpin (matchpin) and
440  * see if it has already been assigned an interrupt.
441  */
442 static int
443 pci_cfgintr_search(struct PIR_entry *pe, int bus, int device, int matchpin, int pin)
444 {
445 	devclass_t		pci_devclass;
446 	device_t		*pci_devices;
447 	int			pci_count;
448 	device_t		*pci_children;
449 	int			pci_childcount;
450 	device_t		*busp, *childp;
451 	int			i, j, irq;
452 
453 	/*
454 	 * Find all the PCI busses.
455 	 */
456 	pci_count = 0;
457 	if ((pci_devclass = devclass_find("pci")) != NULL)
458 		devclass_get_devices(pci_devclass, &pci_devices, &pci_count);
459 
460 	/*
461 	 * Scan all the PCI busses/devices looking for this one.
462 	 */
463 	irq = PCI_INVALID_IRQ;
464 	for (i = 0, busp = pci_devices; (i < pci_count) && (irq == PCI_INVALID_IRQ);
465 	     i++, busp++) {
466 		pci_childcount = 0;
467 		device_get_children(*busp, &pci_children, &pci_childcount);
468 
469 		for (j = 0, childp = pci_children; j < pci_childcount; j++,
470 		    childp++) {
471 			if ((pci_get_bus(*childp) == bus) &&
472 			    (pci_get_slot(*childp) == device) &&
473 			    (pci_get_intpin(*childp) == matchpin)) {
474 				irq = pci_i386_map_intline(pci_get_irq(*childp));
475 				if (irq != PCI_INVALID_IRQ)
476 					PRVERB(("pci_cfgintr_search: linked (%x) to configured irq %d at %d:%d:%d\n",
477 					    pe->pe_intpin[pin - 1].link, irq,
478 					    pci_get_bus(*childp),
479 					    pci_get_slot(*childp),
480 					    pci_get_function(*childp)));
481 				break;
482 			}
483 		}
484 		if (pci_children != NULL)
485 			free(pci_children, M_TEMP);
486 	}
487 	if (pci_devices != NULL)
488 		free(pci_devices, M_TEMP);
489 	return(irq);
490 }
491 
492 /*
493  * Pick a suitable IRQ from those listed as routable to this device.
494  */
495 static int
496 pci_cfgintr_virgin(struct PIR_entry *pe, int pin)
497 {
498 	int		irq, ibit;
499 
500 	/*
501 	 * first scan the set of PCI-only interrupts and see if any of these
502 	 * are routable
503 	 */
504 	for (irq = 0; irq < 16; irq++) {
505 		ibit = (1 << irq);
506 
507 		/* can we use this interrupt? */
508 		if ((pci_route_table->pt_header.ph_pci_irqs & ibit) &&
509 		    (pe->pe_intpin[pin - 1].irqs & ibit)) {
510 			PRVERB(("pci_cfgintr_virgin: using routable PCI-only interrupt %d\n", irq));
511 			return(irq);
512 		}
513 	}
514 
515 	/* life is tough, so just pick an interrupt */
516 	for (irq = 0; irq < 16; irq++) {
517 		ibit = (1 << irq);
518 		if (pe->pe_intpin[pin - 1].irqs & ibit) {
519 			PRVERB(("pci_cfgintr_virgin: using routable interrupt %d\n", irq));
520 			return(irq);
521 		}
522 	}
523 	return(PCI_INVALID_IRQ);
524 }
525 
526 static void
527 pci_print_irqmask(u_int16_t irqs)
528 {
529 	int i, first;
530 
531 	if (irqs == 0) {
532 		printf("none");
533 		return;
534 	}
535 	first = 1;
536 	for (i = 0; i < 16; i++, irqs >>= 1)
537 		if (irqs & 1) {
538 			if (!first)
539 				printf(" ");
540 			else
541 				first = 0;
542 			printf("%d", i);
543 		}
544 }
545 
546 /*
547  * Dump the contents of a PCI BIOS Interrupt Routing Table to the console.
548  */
549 static void
550 pci_print_route_table(struct PIR_table *prt, int size)
551 {
552 	struct PIR_entry *entry;
553 	struct PIR_intpin *intpin;
554 	int i, pin;
555 
556 	printf("PCI-Only Interrupts: ");
557 	pci_print_irqmask(prt->pt_header.ph_pci_irqs);
558 	printf("\nLocation  Bus Device Pin  Link  IRQs\n");
559 	entry = &prt->pt_entry[0];
560 	for (i = 0; i < size; i++, entry++) {
561 		intpin = &entry->pe_intpin[0];
562 		for (pin = 0; pin < 4; pin++, intpin++)
563 			if (intpin->link != 0) {
564 				if (entry->pe_slot == 0)
565 					printf("embedded ");
566 				else
567 					printf("slot %-3d ", entry->pe_slot);
568 				printf(" %3d  %3d    %c   0x%02x  ",
569 				    entry->pe_bus, entry->pe_device,
570 				    'A' + pin, intpin->link);
571 				pci_print_irqmask(intpin->irqs);
572 				printf("\n");
573 			}
574 	}
575 }
576 
577 /*
578  * See if any interrupts for a given PCI bus are routed in the PIR.  Don't
579  * even bother looking if the BIOS doesn't support routing anyways.
580  */
581 int
582 pci_probe_route_table(int bus)
583 {
584 	int i;
585 	u_int16_t v;
586 
587 	v = pcibios_get_version();
588 	if (v < 0x0210)
589 		return (0);
590 	for (i = 0; i < pci_route_count; i++)
591 		if (pci_route_table->pt_entry[i].pe_bus == bus)
592 			return (1);
593 	return (0);
594 }
595 
596 /*
597  * Configuration space access using direct register operations
598  */
599 
600 /* enable configuration space accesses and return data port address */
601 static int
602 pci_cfgenable(unsigned bus, unsigned slot, unsigned func, int reg, int bytes)
603 {
604 	int dataport = 0;
605 
606 	if (bus <= PCI_BUSMAX
607 	    && slot < devmax
608 	    && func <= PCI_FUNCMAX
609 	    && reg <= PCI_REGMAX
610 	    && bytes != 3
611 	    && (unsigned) bytes <= 4
612 	    && (reg & (bytes - 1)) == 0) {
613 		switch (cfgmech) {
614 		case 1:
615 			outl(CONF1_ADDR_PORT, (1 << 31)
616 			    | (bus << 16) | (slot << 11)
617 			    | (func << 8) | (reg & ~0x03));
618 			dataport = CONF1_DATA_PORT + (reg & 0x03);
619 			break;
620 		case 2:
621 			outb(CONF2_ENABLE_PORT, 0xf0 | (func << 1));
622 			outb(CONF2_FORWARD_PORT, bus);
623 			dataport = 0xc000 | (slot << 8) | reg;
624 			break;
625 		}
626 	}
627 	return (dataport);
628 }
629 
630 /* disable configuration space accesses */
631 static void
632 pci_cfgdisable(void)
633 {
634 	switch (cfgmech) {
635 	case 1:
636 		outl(CONF1_ADDR_PORT, 0);
637 		break;
638 	case 2:
639 		outb(CONF2_ENABLE_PORT, 0);
640 		outb(CONF2_FORWARD_PORT, 0);
641 		break;
642 	}
643 }
644 
645 static int
646 pcireg_cfgread(int bus, int slot, int func, int reg, int bytes)
647 {
648 	int data = -1;
649 	int port;
650 
651 	mtx_lock_spin(&pcicfg_mtx);
652 	port = pci_cfgenable(bus, slot, func, reg, bytes);
653 	if (port != 0) {
654 		switch (bytes) {
655 		case 1:
656 			data = inb(port);
657 			break;
658 		case 2:
659 			data = inw(port);
660 			break;
661 		case 4:
662 			data = inl(port);
663 			break;
664 		}
665 		pci_cfgdisable();
666 	}
667 	mtx_unlock_spin(&pcicfg_mtx);
668 	return (data);
669 }
670 
671 static void
672 pcireg_cfgwrite(int bus, int slot, int func, int reg, int data, int bytes)
673 {
674 	int port;
675 
676 	mtx_lock_spin(&pcicfg_mtx);
677 	port = pci_cfgenable(bus, slot, func, reg, bytes);
678 	if (port != 0) {
679 		switch (bytes) {
680 		case 1:
681 			outb(port, data);
682 			break;
683 		case 2:
684 			outw(port, data);
685 			break;
686 		case 4:
687 			outl(port, data);
688 			break;
689 		}
690 		pci_cfgdisable();
691 	}
692 	mtx_unlock_spin(&pcicfg_mtx);
693 }
694 
695 /* check whether the configuration mechanism has been correctly identified */
696 static int
697 pci_cfgcheck(int maxdev)
698 {
699 	uint32_t id, class;
700 	uint8_t header;
701 	uint8_t device;
702 	int port;
703 
704 	if (bootverbose)
705 		printf("pci_cfgcheck:\tdevice ");
706 
707 	for (device = 0; device < maxdev; device++) {
708 		if (bootverbose)
709 			printf("%d ", device);
710 
711 		port = pci_cfgenable(0, device, 0, 0, 4);
712 		id = inl(port);
713 		if (id == 0 || id == 0xffffffff)
714 			continue;
715 
716 		port = pci_cfgenable(0, device, 0, 8, 4);
717 		class = inl(port) >> 8;
718 		if (bootverbose)
719 			printf("[class=%06x] ", class);
720 		if (class == 0 || (class & 0xf870ff) != 0)
721 			continue;
722 
723 		port = pci_cfgenable(0, device, 0, 14, 1);
724 		header = inb(port);
725 		if (bootverbose)
726 			printf("[hdr=%02x] ", header);
727 		if ((header & 0x7e) != 0)
728 			continue;
729 
730 		if (bootverbose)
731 			printf("is there (id=%08x)\n", id);
732 
733 		pci_cfgdisable();
734 		return (1);
735 	}
736 	if (bootverbose)
737 		printf("-- nothing found\n");
738 
739 	pci_cfgdisable();
740 	return (0);
741 }
742 
743 static int
744 pcireg_cfgopen(void)
745 {
746 	uint32_t mode1res, oldval1;
747 	uint8_t mode2res, oldval2;
748 
749 	oldval1 = inl(CONF1_ADDR_PORT);
750 
751 	if (bootverbose) {
752 		printf("pci_open(1):\tmode 1 addr port (0x0cf8) is 0x%08x\n",
753 		    oldval1);
754 	}
755 
756 	if ((oldval1 & CONF1_ENABLE_MSK) == 0) {
757 
758 		cfgmech = 1;
759 		devmax = 32;
760 
761 		outl(CONF1_ADDR_PORT, CONF1_ENABLE_CHK);
762 		outb(CONF1_ADDR_PORT + 3, 0);
763 		mode1res = inl(CONF1_ADDR_PORT);
764 		outl(CONF1_ADDR_PORT, oldval1);
765 
766 		if (bootverbose)
767 			printf("pci_open(1a):\tmode1res=0x%08x (0x%08lx)\n",
768 			    mode1res, CONF1_ENABLE_CHK);
769 
770 		if (mode1res) {
771 			if (pci_cfgcheck(32))
772 				return (cfgmech);
773 		}
774 
775 		outl(CONF1_ADDR_PORT, CONF1_ENABLE_CHK1);
776 		mode1res = inl(CONF1_ADDR_PORT);
777 		outl(CONF1_ADDR_PORT, oldval1);
778 
779 		if (bootverbose)
780 			printf("pci_open(1b):\tmode1res=0x%08x (0x%08lx)\n",
781 			    mode1res, CONF1_ENABLE_CHK1);
782 
783 		if ((mode1res & CONF1_ENABLE_MSK1) == CONF1_ENABLE_RES1) {
784 			if (pci_cfgcheck(32))
785 				return (cfgmech);
786 		}
787 	}
788 
789 	oldval2 = inb(CONF2_ENABLE_PORT);
790 
791 	if (bootverbose) {
792 		printf("pci_open(2):\tmode 2 enable port (0x0cf8) is 0x%02x\n",
793 		    oldval2);
794 	}
795 
796 	if ((oldval2 & 0xf0) == 0) {
797 
798 		cfgmech = 2;
799 		devmax = 16;
800 
801 		outb(CONF2_ENABLE_PORT, CONF2_ENABLE_CHK);
802 		mode2res = inb(CONF2_ENABLE_PORT);
803 		outb(CONF2_ENABLE_PORT, oldval2);
804 
805 		if (bootverbose)
806 			printf("pci_open(2a):\tmode2res=0x%02x (0x%02x)\n",
807 			    mode2res, CONF2_ENABLE_CHK);
808 
809 		if (mode2res == CONF2_ENABLE_RES) {
810 			if (bootverbose)
811 				printf("pci_open(2a):\tnow trying mechanism 2\n");
812 
813 			if (pci_cfgcheck(16))
814 				return (cfgmech);
815 		}
816 	}
817 
818 	cfgmech = 0;
819 	devmax = 0;
820 	return (cfgmech);
821 }
822 
823