xref: /freebsd/sys/i386/pci/pci_cfgreg.c (revision 52ec752989b2e6d4e9a59a8ff25d8ff596d85e62)
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 <sys/sysctl.h>
41 #include <vm/vm.h>
42 #include <vm/pmap.h>
43 #include <machine/md_var.h>
44 #include <dev/pci/pcivar.h>
45 #include <dev/pci/pcireg.h>
46 #include <isa/isavar.h>
47 #include <machine/pci_cfgreg.h>
48 #include <machine/segments.h>
49 #include <machine/pc/bios.h>
50 
51 #include "pcib_if.h"
52 
53 #define PRVERB(a) do {							\
54 	if (bootverbose)						\
55 		printf a ;						\
56 } while(0)
57 
58 static int cfgmech;
59 static int devmax;
60 
61 static int	pci_cfgintr_valid(struct PIR_entry *pe, int pin, int irq);
62 static int	pci_cfgintr_unique(struct PIR_entry *pe, int pin);
63 static int	pci_cfgintr_linked(struct PIR_entry *pe, int pin);
64 static int	pci_cfgintr_search(struct PIR_entry *pe, int bus, int device, int matchpin, int pin);
65 static int	pci_cfgintr_virgin(struct PIR_entry *pe, int pin);
66 
67 static void	pci_print_irqmask(u_int16_t irqs);
68 static void	pci_print_route_table(struct PIR_table *prt, int size);
69 static int	pcireg_cfgread(int bus, int slot, int func, int reg, int bytes);
70 static void	pcireg_cfgwrite(int bus, int slot, int func, int reg, int data, int bytes);
71 static int	pcireg_cfgopen(void);
72 
73 static struct PIR_table *pci_route_table;
74 static int pci_route_count;
75 
76 static struct mtx pcicfg_mtx;
77 
78 /* sysctl vars */
79 SYSCTL_DECL(_hw_pci);
80 
81 #ifdef PC98
82 #define PCI_IRQ_OVERRIDE_MASK 0x3e68
83 #else
84 #define PCI_IRQ_OVERRIDE_MASK 0xdef4
85 #endif
86 
87 static uint32_t pci_irq_override_mask = PCI_IRQ_OVERRIDE_MASK;
88 TUNABLE_INT("hw.pci.irq_override_mask", &pci_irq_override_mask);
89 SYSCTL_INT(_hw_pci, OID_AUTO, irq_override_mask, CTLFLAG_RDTUN,
90     &pci_irq_override_mask, PCI_IRQ_OVERRIDE_MASK,
91     "Mask of allowed irqs to try to route when it has no good clue about\n"
92     "which irqs it should use.");
93 
94 
95 /*
96  * Some BIOS writers seem to want to ignore the spec and put
97  * 0 in the intline rather than 255 to indicate none.  Some use
98  * numbers in the range 128-254 to indicate something strange and
99  * apparently undocumented anywhere.  Assume these are completely bogus
100  * and map them to 255, which means "none".
101  */
102 static __inline__ int
103 pci_i386_map_intline(int line)
104 {
105 	if (line == 0 || line >= 128)
106 		return (PCI_INVALID_IRQ);
107 	return (line);
108 }
109 
110 static u_int16_t
111 pcibios_get_version(void)
112 {
113 	struct bios_regs args;
114 
115 	if (PCIbios.ventry == 0) {
116 		PRVERB(("pcibios: No call entry point\n"));
117 		return (0);
118 	}
119 	args.eax = PCIBIOS_BIOS_PRESENT;
120 	if (bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL))) {
121 		PRVERB(("pcibios: BIOS_PRESENT call failed\n"));
122 		return (0);
123 	}
124 	if (args.edx != 0x20494350) {
125 		PRVERB(("pcibios: BIOS_PRESENT didn't return 'PCI ' in edx\n"));
126 		return (0);
127 	}
128 	return (args.ebx & 0xffff);
129 }
130 
131 /*
132  * Initialise access to PCI configuration space
133  */
134 int
135 pci_cfgregopen(void)
136 {
137 	static int		opened = 0;
138 	u_long			sigaddr;
139 	static struct PIR_table	*pt;
140 	u_int16_t		v;
141 	u_int8_t		ck, *cv;
142 	int			i;
143 
144 	if (opened)
145 		return(1);
146 
147 	if (pcireg_cfgopen() == 0)
148 		return(0);
149 
150 	v = pcibios_get_version();
151 	if (v > 0)
152 		printf("pcibios: BIOS version %x.%02x\n", (v & 0xff00) >> 8,
153 		    v & 0xff);
154 
155 	/*
156 	 * Look for the interrupt routing table.
157 	 *
158 	 * We use PCI BIOS's PIR table if it's available $PIR is the
159 	 * standard way to do this.  Sadly, some machines are not
160 	 * standards conforming and have _PIR instead.  We shrug and cope
161 	 * by looking for both.
162 	 */
163 	if (pcibios_get_version() >= 0x0210 && pt == NULL) {
164 		sigaddr = bios_sigsearch(0, "$PIR", 4, 16, 0);
165 		if (sigaddr == 0)
166 			sigaddr = bios_sigsearch(0, "_PIR", 4, 16, 0);
167 		if (sigaddr != 0) {
168 			pt = (struct PIR_table *)(uintptr_t)
169 			    BIOS_PADDRTOVADDR(sigaddr);
170 			for (cv = (u_int8_t *)pt, ck = 0, i = 0;
171 			     i < (pt->pt_header.ph_length); i++) {
172 				ck += cv[i];
173 			}
174 			if (ck == 0 && pt->pt_header.ph_length >
175 			    sizeof(struct PIR_header)) {
176 				pci_route_table = pt;
177 				pci_route_count = (pt->pt_header.ph_length -
178 				    sizeof(struct PIR_header)) /
179 				    sizeof(struct PIR_entry);
180 				printf("Using $PIR table, %d entries at %p\n",
181 				    pci_route_count, pci_route_table);
182 				if (bootverbose)
183 					pci_print_route_table(pci_route_table,
184 					    pci_route_count);
185 			}
186 		}
187 	}
188 	mtx_init(&pcicfg_mtx, "pcicfg", NULL, MTX_SPIN);
189 	opened = 1;
190 	return(1);
191 }
192 
193 /*
194  * Read configuration space register
195  */
196 u_int32_t
197 pci_cfgregread(int bus, int slot, int func, int reg, int bytes)
198 {
199 	uint32_t line;
200 
201 	/*
202 	 * Some BIOS writers seem to want to ignore the spec and put
203 	 * 0 in the intline rather than 255 to indicate none.  The rest of
204 	 * the code uses 255 as an invalid IRQ.
205 	 */
206 	if (reg == PCIR_INTLINE && bytes == 1) {
207 		line = pcireg_cfgread(bus, slot, func, PCIR_INTLINE, 1);
208 		return (pci_i386_map_intline(line));
209 	}
210 	return (pcireg_cfgread(bus, slot, func, reg, bytes));
211 }
212 
213 /*
214  * Write configuration space register
215  */
216 void
217 pci_cfgregwrite(int bus, int slot, int func, int reg, u_int32_t data, int bytes)
218 {
219 
220 	pcireg_cfgwrite(bus, slot, func, reg, data, bytes);
221 }
222 
223 /*
224  * Route a PCI interrupt
225  */
226 int
227 pci_cfgintr(int bus, int device, int pin, int oldirq)
228 {
229 	struct PIR_entry	*pe;
230 	int			i, irq;
231 	struct bios_regs	args;
232 	u_int16_t		v;
233  	int already = 0;
234  	int errok = 0;
235 
236 	v = pcibios_get_version();
237 	if (v < 0x0210) {
238 		PRVERB((
239 		"pci_cfgintr: BIOS %x.%02x doesn't support interrupt routing\n",
240 		    (v & 0xff00) >> 8, v & 0xff));
241 		return (PCI_INVALID_IRQ);
242 	}
243 	if ((bus < 0) || (bus > 255) || (device < 0) || (device > 255) ||
244 	    (pin < 1) || (pin > 4))
245 		return(PCI_INVALID_IRQ);
246 
247 	/*
248 	 * Scan the entry table for a contender
249 	 */
250 	for (i = 0, pe = &pci_route_table->pt_entry[0]; i < pci_route_count;
251 	     i++, pe++) {
252 		if ((bus != pe->pe_bus) || (device != pe->pe_device))
253 			continue;
254 		/*
255 		 * A link of 0 means that this intpin is not connected to
256 		 * any other device's interrupt pins and is not connected to
257 		 * any of the Interrupt Router's interrupt pins, so we can't
258 		 * route it.
259 		 */
260 		if (pe->pe_intpin[pin - 1].link == 0)
261 			continue;
262 
263 		if (pci_cfgintr_valid(pe, pin, oldirq)) {
264 			printf("pci_cfgintr: %d:%d INT%c BIOS irq %d\n", bus,
265 			    device, 'A' + pin - 1, oldirq);
266 			return (oldirq);
267 		}
268 
269 		/*
270 		 * We try to find a linked interrupt, then we look to see
271 		 * if the interrupt is uniquely routed, then we look for
272 		 * a virgin interrupt.  The virgin interrupt should return
273 		 * an interrupt we can route, but if that fails, maybe we
274 		 * should try harder to route a different interrupt.
275 		 * However, experience has shown that that's rarely the
276 		 * failure mode we see.
277 		 */
278 		irq = pci_cfgintr_linked(pe, pin);
279 		if (irq != PCI_INVALID_IRQ)
280 			already = 1;
281 		if (irq == PCI_INVALID_IRQ) {
282 			irq = pci_cfgintr_unique(pe, pin);
283 			if (irq != PCI_INVALID_IRQ)
284 				errok = 1;
285 		}
286 		if (irq == PCI_INVALID_IRQ)
287 			irq = pci_cfgintr_virgin(pe, pin);
288 		if (irq == PCI_INVALID_IRQ)
289 			break;
290 
291 		/*
292 		 * Ask the BIOS to route the interrupt.  If we picked an
293 		 * interrupt that failed, we should really try other
294 		 * choices that the BIOS offers us.
295 		 *
296 		 * For uniquely routed interrupts, we need to try
297 		 * to route them on some machines.  Yet other machines
298 		 * fail to route, so we have to pretend that in that
299 		 * case it worked.  Isn't pc hardware fun?
300 		 *
301 		 * NOTE: if we want to whack hardware to do this, then
302 		 * I think the right way to do that would be to have
303 		 * bridge drivers that do this.  I'm not sure that the
304 		 * $PIR table would be valid for those interrupt
305 		 * routers.
306 		 */
307 		args.eax = PCIBIOS_ROUTE_INTERRUPT;
308 		args.ebx = (bus << 8) | (device << 3);
309 		/* pin value is 0xa - 0xd */
310 		args.ecx = (irq << 8) | (0xa + pin - 1);
311 		if (!already &&
312 		    bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL)) &&
313 		    !errok) {
314 			PRVERB(("pci_cfgintr: ROUTE_INTERRUPT failed.\n"));
315 			return(PCI_INVALID_IRQ);
316 		}
317 		printf("pci_cfgintr: %d:%d INT%c routed to irq %d\n", bus,
318 		    device, 'A' + pin - 1, irq);
319 		return(irq);
320 	}
321 
322 	PRVERB(("pci_cfgintr: can't route an interrupt to %d:%d INT%c\n", bus,
323 	    device, 'A' + pin - 1));
324 	return(PCI_INVALID_IRQ);
325 }
326 
327 /*
328  * Check to see if an existing IRQ setting is valid.
329  */
330 static int
331 pci_cfgintr_valid(struct PIR_entry *pe, int pin, int irq)
332 {
333 	uint32_t irqmask;
334 
335 	if (!PCI_INTERRUPT_VALID(irq))
336 		return (0);
337 	irqmask = pe->pe_intpin[pin - 1].irqs;
338 	if (irqmask & (1 << irq)) {
339 		PRVERB(("pci_cfgintr_valid: BIOS irq %d is valid\n", irq));
340 		return (1);
341 	}
342 	return (0);
343 }
344 
345 /*
346  * Look to see if the routing table claims this pin is uniquely routed.
347  */
348 static int
349 pci_cfgintr_unique(struct PIR_entry *pe, int pin)
350 {
351 	int		irq;
352 	uint32_t	irqmask;
353 
354 	irqmask = pe->pe_intpin[pin - 1].irqs;
355 	if (irqmask != 0 && powerof2(irqmask)) {
356 		irq = ffs(irqmask) - 1;
357 		PRVERB(("pci_cfgintr_unique: hard-routed to irq %d\n", irq));
358 		return(irq);
359 	}
360 	return(PCI_INVALID_IRQ);
361 }
362 
363 /*
364  * Look for another device which shares the same link byte and
365  * already has a unique IRQ, or which has had one routed already.
366  */
367 static int
368 pci_cfgintr_linked(struct PIR_entry *pe, int pin)
369 {
370 	struct PIR_entry	*oe;
371 	struct PIR_intpin	*pi;
372 	int			i, j, irq;
373 
374 	/*
375 	 * Scan table slots.
376 	 */
377 	for (i = 0, oe = &pci_route_table->pt_entry[0]; i < pci_route_count;
378 	     i++, oe++) {
379 		/* scan interrupt pins */
380 		for (j = 0, pi = &oe->pe_intpin[0]; j < 4; j++, pi++) {
381 
382 			/* don't look at the entry we're trying to match */
383 			if ((pe == oe) && (i == (pin - 1)))
384 				continue;
385 			/* compare link bytes */
386 			if (pi->link != pe->pe_intpin[pin - 1].link)
387 				continue;
388 			/* link destination mapped to a unique interrupt? */
389 			if (pi->irqs != 0 && powerof2(pi->irqs)) {
390 				irq = ffs(pi->irqs) - 1;
391 				PRVERB(("pci_cfgintr_linked: linked (%x) to hard-routed irq %d\n",
392 				    pi->link, irq));
393 				return(irq);
394 			}
395 
396 			/*
397 			 * look for the real PCI device that matches this
398 			 * table entry
399 			 */
400 			irq = pci_cfgintr_search(pe, oe->pe_bus, oe->pe_device,
401 			    j + 1, pin);
402 			if (irq != PCI_INVALID_IRQ)
403 				return(irq);
404 		}
405 	}
406 	return(PCI_INVALID_IRQ);
407 }
408 
409 /*
410  * Scan for the real PCI device at (bus)/(device) using intpin (matchpin) and
411  * see if it has already been assigned an interrupt.
412  */
413 static int
414 pci_cfgintr_search(struct PIR_entry *pe, int bus, int device, int matchpin, int pin)
415 {
416 	devclass_t		pci_devclass;
417 	device_t		*pci_devices;
418 	int			pci_count;
419 	device_t		*pci_children;
420 	int			pci_childcount;
421 	device_t		*busp, *childp;
422 	int			i, j, irq;
423 
424 	/*
425 	 * Find all the PCI busses.
426 	 */
427 	pci_count = 0;
428 	if ((pci_devclass = devclass_find("pci")) != NULL)
429 		devclass_get_devices(pci_devclass, &pci_devices, &pci_count);
430 
431 	/*
432 	 * Scan all the PCI busses/devices looking for this one.
433 	 */
434 	irq = PCI_INVALID_IRQ;
435 	for (i = 0, busp = pci_devices; (i < pci_count) && (irq == PCI_INVALID_IRQ);
436 	     i++, busp++) {
437 		pci_childcount = 0;
438 		device_get_children(*busp, &pci_children, &pci_childcount);
439 
440 		for (j = 0, childp = pci_children; j < pci_childcount; j++,
441 		    childp++) {
442 			if ((pci_get_bus(*childp) == bus) &&
443 			    (pci_get_slot(*childp) == device) &&
444 			    (pci_get_intpin(*childp) == matchpin)) {
445 				irq = pci_i386_map_intline(pci_get_irq(*childp));
446 				if (irq != PCI_INVALID_IRQ)
447 					PRVERB(("pci_cfgintr_search: linked (%x) to configured irq %d at %d:%d:%d\n",
448 					    pe->pe_intpin[pin - 1].link, irq,
449 					    pci_get_bus(*childp),
450 					    pci_get_slot(*childp),
451 					    pci_get_function(*childp)));
452 				break;
453 			}
454 		}
455 		if (pci_children != NULL)
456 			free(pci_children, M_TEMP);
457 	}
458 	if (pci_devices != NULL)
459 		free(pci_devices, M_TEMP);
460 	return(irq);
461 }
462 
463 /*
464  * Pick a suitable IRQ from those listed as routable to this device.
465  */
466 static int
467 pci_cfgintr_virgin(struct PIR_entry *pe, int pin)
468 {
469 	int		irq, ibit;
470 
471 	/*
472 	 * first scan the set of PCI-only interrupts and see if any of these
473 	 * are routable
474 	 */
475 	for (irq = 0; irq < 16; irq++) {
476 		ibit = (1 << irq);
477 
478 		/* can we use this interrupt? */
479 		if ((pci_route_table->pt_header.ph_pci_irqs & ibit) &&
480 		    (pe->pe_intpin[pin - 1].irqs & ibit)) {
481 			PRVERB(("pci_cfgintr_virgin: using routable PCI-only interrupt %d\n", irq));
482 			return(irq);
483 		}
484 	}
485 
486 	/* life is tough, so just pick an interrupt */
487 	for (irq = 0; irq < 16; irq++) {
488 		ibit = (1 << irq);
489 		if ((ibit & pci_irq_override_mask) == 0)
490 			continue;
491 		if (pe->pe_intpin[pin - 1].irqs & ibit) {
492 			PRVERB(("pci_cfgintr_virgin: using routable interrupt %d\n", irq));
493 			return(irq);
494 		}
495 	}
496 	return(PCI_INVALID_IRQ);
497 }
498 
499 static void
500 pci_print_irqmask(u_int16_t irqs)
501 {
502 	int i, first;
503 
504 	if (irqs == 0) {
505 		printf("none");
506 		return;
507 	}
508 	first = 1;
509 	for (i = 0; i < 16; i++, irqs >>= 1)
510 		if (irqs & 1) {
511 			if (!first)
512 				printf(" ");
513 			else
514 				first = 0;
515 			printf("%d", i);
516 		}
517 }
518 
519 /*
520  * Dump the contents of a PCI BIOS Interrupt Routing Table to the console.
521  */
522 static void
523 pci_print_route_table(struct PIR_table *prt, int size)
524 {
525 	struct PIR_entry *entry;
526 	struct PIR_intpin *intpin;
527 	int i, pin;
528 
529 	printf("PCI-Only Interrupts: ");
530 	pci_print_irqmask(prt->pt_header.ph_pci_irqs);
531 	printf("\nLocation  Bus Device Pin  Link  IRQs\n");
532 	entry = &prt->pt_entry[0];
533 	for (i = 0; i < size; i++, entry++) {
534 		intpin = &entry->pe_intpin[0];
535 		for (pin = 0; pin < 4; pin++, intpin++)
536 			if (intpin->link != 0) {
537 				if (entry->pe_slot == 0)
538 					printf("embedded ");
539 				else
540 					printf("slot %-3d ", entry->pe_slot);
541 				printf(" %3d  %3d    %c   0x%02x  ",
542 				    entry->pe_bus, entry->pe_device,
543 				    'A' + pin, intpin->link);
544 				pci_print_irqmask(intpin->irqs);
545 				printf("\n");
546 			}
547 	}
548 }
549 
550 /*
551  * See if any interrupts for a given PCI bus are routed in the PIR.  Don't
552  * even bother looking if the BIOS doesn't support routing anyways.
553  */
554 int
555 pci_probe_route_table(int bus)
556 {
557 	int i;
558 	u_int16_t v;
559 
560 	v = pcibios_get_version();
561 	if (v < 0x0210)
562 		return (0);
563 	for (i = 0; i < pci_route_count; i++)
564 		if (pci_route_table->pt_entry[i].pe_bus == bus)
565 			return (1);
566 	return (0);
567 }
568 
569 /*
570  * Configuration space access using direct register operations
571  */
572 
573 /* enable configuration space accesses and return data port address */
574 static int
575 pci_cfgenable(unsigned bus, unsigned slot, unsigned func, int reg, int bytes)
576 {
577 	int dataport = 0;
578 
579 	if (bus <= PCI_BUSMAX
580 	    && slot < devmax
581 	    && func <= PCI_FUNCMAX
582 	    && reg <= PCI_REGMAX
583 	    && bytes != 3
584 	    && (unsigned) bytes <= 4
585 	    && (reg & (bytes - 1)) == 0) {
586 		switch (cfgmech) {
587 		case 1:
588 			outl(CONF1_ADDR_PORT, (1 << 31)
589 			    | (bus << 16) | (slot << 11)
590 			    | (func << 8) | (reg & ~0x03));
591 			dataport = CONF1_DATA_PORT + (reg & 0x03);
592 			break;
593 		case 2:
594 			outb(CONF2_ENABLE_PORT, 0xf0 | (func << 1));
595 			outb(CONF2_FORWARD_PORT, bus);
596 			dataport = 0xc000 | (slot << 8) | reg;
597 			break;
598 		}
599 	}
600 	return (dataport);
601 }
602 
603 /* disable configuration space accesses */
604 static void
605 pci_cfgdisable(void)
606 {
607 	switch (cfgmech) {
608 	case 1:
609 		outl(CONF1_ADDR_PORT, 0);
610 		break;
611 	case 2:
612 		outb(CONF2_ENABLE_PORT, 0);
613 		outb(CONF2_FORWARD_PORT, 0);
614 		break;
615 	}
616 }
617 
618 static int
619 pcireg_cfgread(int bus, int slot, int func, int reg, int bytes)
620 {
621 	int data = -1;
622 	int port;
623 
624 	mtx_lock_spin(&pcicfg_mtx);
625 	port = pci_cfgenable(bus, slot, func, reg, bytes);
626 	if (port != 0) {
627 		switch (bytes) {
628 		case 1:
629 			data = inb(port);
630 			break;
631 		case 2:
632 			data = inw(port);
633 			break;
634 		case 4:
635 			data = inl(port);
636 			break;
637 		}
638 		pci_cfgdisable();
639 	}
640 	mtx_unlock_spin(&pcicfg_mtx);
641 	return (data);
642 }
643 
644 static void
645 pcireg_cfgwrite(int bus, int slot, int func, int reg, int data, int bytes)
646 {
647 	int port;
648 
649 	mtx_lock_spin(&pcicfg_mtx);
650 	port = pci_cfgenable(bus, slot, func, reg, bytes);
651 	if (port != 0) {
652 		switch (bytes) {
653 		case 1:
654 			outb(port, data);
655 			break;
656 		case 2:
657 			outw(port, data);
658 			break;
659 		case 4:
660 			outl(port, data);
661 			break;
662 		}
663 		pci_cfgdisable();
664 	}
665 	mtx_unlock_spin(&pcicfg_mtx);
666 }
667 
668 /* check whether the configuration mechanism has been correctly identified */
669 static int
670 pci_cfgcheck(int maxdev)
671 {
672 	uint32_t id, class;
673 	uint8_t header;
674 	uint8_t device;
675 	int port;
676 
677 	if (bootverbose)
678 		printf("pci_cfgcheck:\tdevice ");
679 
680 	for (device = 0; device < maxdev; device++) {
681 		if (bootverbose)
682 			printf("%d ", device);
683 
684 		port = pci_cfgenable(0, device, 0, 0, 4);
685 		id = inl(port);
686 		if (id == 0 || id == 0xffffffff)
687 			continue;
688 
689 		port = pci_cfgenable(0, device, 0, 8, 4);
690 		class = inl(port) >> 8;
691 		if (bootverbose)
692 			printf("[class=%06x] ", class);
693 		if (class == 0 || (class & 0xf870ff) != 0)
694 			continue;
695 
696 		port = pci_cfgenable(0, device, 0, 14, 1);
697 		header = inb(port);
698 		if (bootverbose)
699 			printf("[hdr=%02x] ", header);
700 		if ((header & 0x7e) != 0)
701 			continue;
702 
703 		if (bootverbose)
704 			printf("is there (id=%08x)\n", id);
705 
706 		pci_cfgdisable();
707 		return (1);
708 	}
709 	if (bootverbose)
710 		printf("-- nothing found\n");
711 
712 	pci_cfgdisable();
713 	return (0);
714 }
715 
716 static int
717 pcireg_cfgopen(void)
718 {
719 	uint32_t mode1res, oldval1;
720 	uint8_t mode2res, oldval2;
721 
722 	oldval1 = inl(CONF1_ADDR_PORT);
723 
724 	if (bootverbose) {
725 		printf("pci_open(1):\tmode 1 addr port (0x0cf8) is 0x%08x\n",
726 		    oldval1);
727 	}
728 
729 	if ((oldval1 & CONF1_ENABLE_MSK) == 0) {
730 
731 		cfgmech = 1;
732 		devmax = 32;
733 
734 		outl(CONF1_ADDR_PORT, CONF1_ENABLE_CHK);
735 		DELAY(1);
736 		mode1res = inl(CONF1_ADDR_PORT);
737 		outl(CONF1_ADDR_PORT, oldval1);
738 
739 		if (bootverbose)
740 			printf("pci_open(1a):\tmode1res=0x%08x (0x%08lx)\n",
741 			    mode1res, CONF1_ENABLE_CHK);
742 
743 		if (mode1res) {
744 			if (pci_cfgcheck(32))
745 				return (cfgmech);
746 		}
747 
748 		outl(CONF1_ADDR_PORT, CONF1_ENABLE_CHK1);
749 		mode1res = inl(CONF1_ADDR_PORT);
750 		outl(CONF1_ADDR_PORT, oldval1);
751 
752 		if (bootverbose)
753 			printf("pci_open(1b):\tmode1res=0x%08x (0x%08lx)\n",
754 			    mode1res, CONF1_ENABLE_CHK1);
755 
756 		if ((mode1res & CONF1_ENABLE_MSK1) == CONF1_ENABLE_RES1) {
757 			if (pci_cfgcheck(32))
758 				return (cfgmech);
759 		}
760 	}
761 
762 	oldval2 = inb(CONF2_ENABLE_PORT);
763 
764 	if (bootverbose) {
765 		printf("pci_open(2):\tmode 2 enable port (0x0cf8) is 0x%02x\n",
766 		    oldval2);
767 	}
768 
769 	if ((oldval2 & 0xf0) == 0) {
770 
771 		cfgmech = 2;
772 		devmax = 16;
773 
774 		outb(CONF2_ENABLE_PORT, CONF2_ENABLE_CHK);
775 		mode2res = inb(CONF2_ENABLE_PORT);
776 		outb(CONF2_ENABLE_PORT, oldval2);
777 
778 		if (bootverbose)
779 			printf("pci_open(2a):\tmode2res=0x%02x (0x%02x)\n",
780 			    mode2res, CONF2_ENABLE_CHK);
781 
782 		if (mode2res == CONF2_ENABLE_RES) {
783 			if (bootverbose)
784 				printf("pci_open(2a):\tnow trying mechanism 2\n");
785 
786 			if (pci_cfgcheck(16))
787 				return (cfgmech);
788 		}
789 	}
790 
791 	cfgmech = 0;
792 	devmax = 0;
793 	return (cfgmech);
794 }
795 
796