xref: /freebsd/sys/i386/pci/pci_pir.c (revision f0a75d274af375d15b97b830966b99a02b7db911)
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, John Baldwin <jhb@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 <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/bus.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/module.h>
39 #include <sys/sysctl.h>
40 #include <vm/vm.h>
41 #include <vm/pmap.h>
42 #include <vm/vm_param.h>
43 #include <machine/md_var.h>
44 #include <dev/pci/pcivar.h>
45 #include <dev/pci/pcireg.h>
46 #include <machine/pci_cfgreg.h>
47 #include <machine/segments.h>
48 #include <machine/pc/bios.h>
49 
50 #define	NUM_ISA_INTERRUPTS	16
51 
52 /*
53  * A link device.  Loosely based on the ACPI PCI link device.  This doesn't
54  * try to support priorities for different ISA interrupts.
55  */
56 struct pci_link {
57 	TAILQ_ENTRY(pci_link) pl_links;
58 	uint8_t		pl_id;
59 	uint8_t		pl_irq;
60 	uint16_t	pl_irqmask;
61 	int		pl_references;
62 	int		pl_routed;
63 };
64 
65 struct pci_link_lookup {
66 	struct pci_link	**pci_link_ptr;
67 	int		bus;
68 	int		device;
69 	int		pin;
70 };
71 
72 struct pci_dev_lookup {
73 	uint8_t		link;
74 	int		bus;
75 	int		device;
76 	int		pin;
77 };
78 
79 typedef void pir_entry_handler(struct PIR_entry *entry,
80     struct PIR_intpin* intpin, void *arg);
81 
82 static void	pci_print_irqmask(u_int16_t irqs);
83 static int	pci_pir_biosroute(int bus, int device, int func, int pin,
84 		    int irq);
85 static int	pci_pir_choose_irq(struct pci_link *pci_link, int irqmask);
86 static void	pci_pir_create_links(struct PIR_entry *entry,
87 		    struct PIR_intpin *intpin, void *arg);
88 static void	pci_pir_dump_links(void);
89 static struct pci_link *pci_pir_find_link(uint8_t link_id);
90 static void	pci_pir_find_link_handler(struct PIR_entry *entry,
91 		    struct PIR_intpin *intpin, void *arg);
92 static void	pci_pir_initial_irqs(struct PIR_entry *entry,
93 		    struct PIR_intpin *intpin, void *arg);
94 static void	pci_pir_parse(void);
95 static uint8_t	pci_pir_search_irq(int bus, int device, int pin);
96 static int	pci_pir_valid_irq(struct pci_link *pci_link, int irq);
97 static void	pci_pir_walk_table(pir_entry_handler *handler, void *arg);
98 
99 static MALLOC_DEFINE(M_PIR, "$PIR", "$PIR structures");
100 
101 static struct PIR_table *pci_route_table;
102 static device_t pir_device;
103 static int pci_route_count, pir_bios_irqs, pir_parsed;
104 static TAILQ_HEAD(, pci_link) pci_links;
105 static int pir_interrupt_weight[NUM_ISA_INTERRUPTS];
106 
107 /* sysctl vars */
108 SYSCTL_DECL(_hw_pci);
109 
110 /* XXX this likely should live in a header file */
111 #ifdef PC98
112 /* IRQs 3, 5, 7, 9, 10, 11, 12, 13 */
113 #define PCI_IRQ_OVERRIDE_MASK 0x3e68
114 #else
115 /* IRQs 3, 4, 5, 6, 7, 9, 10, 11, 12, 14, 15 */
116 #define PCI_IRQ_OVERRIDE_MASK 0xdef8
117 #endif
118 
119 static uint32_t pci_irq_override_mask = PCI_IRQ_OVERRIDE_MASK;
120 TUNABLE_INT("hw.pci.irq_override_mask", &pci_irq_override_mask);
121 SYSCTL_INT(_hw_pci, OID_AUTO, irq_override_mask, CTLFLAG_RDTUN,
122     &pci_irq_override_mask, PCI_IRQ_OVERRIDE_MASK,
123     "Mask of allowed irqs to try to route when it has no good clue about\n"
124     "which irqs it should use.");
125 
126 /*
127  * Look for the interrupt routing table.
128  *
129  * We use PCI BIOS's PIR table if it's available. $PIR is the standard way
130  * to do this.  Sadly, some machines are not standards conforming and have
131  * _PIR instead.  We shrug and cope by looking for both.
132  */
133 void
134 pci_pir_open(void)
135 {
136 	struct PIR_table *pt;
137 	uint32_t sigaddr;
138 	int i;
139 	uint8_t ck, *cv;
140 
141 	/* Don't try if we've already found a table. */
142 	if (pci_route_table != NULL)
143 		return;
144 
145 	/* Look for $PIR and then _PIR. */
146 	sigaddr = bios_sigsearch(0, "$PIR", 4, 16, 0);
147 	if (sigaddr == 0)
148 		sigaddr = bios_sigsearch(0, "_PIR", 4, 16, 0);
149 	if (sigaddr == 0)
150 		return;
151 
152 	/* If we found something, check the checksum and length. */
153 	/* XXX - Use pmap_mapdev()? */
154 	pt = (struct PIR_table *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
155 	if (pt->pt_header.ph_length <= sizeof(struct PIR_header))
156 		return;
157 	for (cv = (u_int8_t *)pt, ck = 0, i = 0;
158 	     i < (pt->pt_header.ph_length); i++)
159 		ck += cv[i];
160 	if (ck != 0)
161 		return;
162 
163 	/* Ok, we've got a valid table. */
164 	pci_route_table = pt;
165 	pci_route_count = (pt->pt_header.ph_length -
166 	    sizeof(struct PIR_header)) /
167 	    sizeof(struct PIR_entry);
168 }
169 
170 /*
171  * Find the pci_link structure for a given link ID.
172  */
173 static struct pci_link *
174 pci_pir_find_link(uint8_t link_id)
175 {
176 	struct pci_link *pci_link;
177 
178 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
179 		if (pci_link->pl_id == link_id)
180 			return (pci_link);
181 	}
182 	return (NULL);
183 }
184 
185 /*
186  * Find the link device associated with a PCI device in the table.
187  */
188 static void
189 pci_pir_find_link_handler(struct PIR_entry *entry, struct PIR_intpin *intpin,
190     void *arg)
191 {
192 	struct pci_link_lookup *lookup;
193 
194 	lookup = (struct pci_link_lookup *)arg;
195 	if (entry->pe_bus == lookup->bus &&
196 	    entry->pe_device == lookup->device &&
197 	    intpin - entry->pe_intpin == lookup->pin)
198 		*lookup->pci_link_ptr = pci_pir_find_link(intpin->link);
199 }
200 
201 /*
202  * Check to see if a possible IRQ setting is valid.
203  */
204 static int
205 pci_pir_valid_irq(struct pci_link *pci_link, int irq)
206 {
207 
208 	if (!PCI_INTERRUPT_VALID(irq))
209 		return (0);
210 	return (pci_link->pl_irqmask & (1 << irq));
211 }
212 
213 /*
214  * Walk the $PIR executing the worker function for each valid intpin entry
215  * in the table.  The handler is passed a pointer to both the entry and
216  * the intpin in the entry.
217  */
218 static void
219 pci_pir_walk_table(pir_entry_handler *handler, void *arg)
220 {
221 	struct PIR_entry *entry;
222 	struct PIR_intpin *intpin;
223 	int i, pin;
224 
225 	entry = &pci_route_table->pt_entry[0];
226 	for (i = 0; i < pci_route_count; i++, entry++) {
227 		intpin = &entry->pe_intpin[0];
228 		for (pin = 0; pin < 4; pin++, intpin++)
229 			if (intpin->link != 0)
230 				handler(entry, intpin, arg);
231 	}
232 }
233 
234 static void
235 pci_pir_create_links(struct PIR_entry *entry, struct PIR_intpin *intpin,
236     void *arg)
237 {
238 	struct pci_link *pci_link;
239 
240 	pci_link = pci_pir_find_link(intpin->link);
241 	if (pci_link != NULL) {
242 		pci_link->pl_references++;
243 		if (intpin->irqs != pci_link->pl_irqmask) {
244 			if (bootverbose)
245 				printf(
246 	"$PIR: Entry %d.%d.INT%c has different mask for link %#x, merging\n",
247 				    entry->pe_bus, entry->pe_device,
248 				    (intpin - entry->pe_intpin) + 'A',
249 				    pci_link->pl_id);
250 			pci_link->pl_irqmask &= intpin->irqs;
251 		}
252 	} else {
253 		pci_link = malloc(sizeof(struct pci_link), M_PIR, M_WAITOK);
254 		pci_link->pl_id = intpin->link;
255 		pci_link->pl_irqmask = intpin->irqs;
256 		pci_link->pl_irq = PCI_INVALID_IRQ;
257 		pci_link->pl_references = 1;
258 		pci_link->pl_routed = 0;
259 		TAILQ_INSERT_TAIL(&pci_links, pci_link, pl_links);
260 	}
261 }
262 
263 /*
264  * Look to see if any of the function on the PCI device at bus/device have
265  * an interrupt routed to intpin 'pin' by the BIOS.
266  */
267 static uint8_t
268 pci_pir_search_irq(int bus, int device, int pin)
269 {
270 	uint32_t value;
271 	uint8_t func, maxfunc;
272 
273 	/* See if we have a valid device at function 0. */
274 	value = pci_cfgregread(bus, device, 0, PCIR_HDRTYPE, 1);
275 	if ((value & PCIM_HDRTYPE) > PCI_MAXHDRTYPE)
276 		return (PCI_INVALID_IRQ);
277 	if (value & PCIM_MFDEV)
278 		maxfunc = PCI_FUNCMAX;
279 	else
280 		maxfunc = 0;
281 
282 	/* Scan all possible functions at this device. */
283 	for (func = 0; func <= maxfunc; func++) {
284 		value = pci_cfgregread(bus, device, func, PCIR_DEVVENDOR, 4);
285 		if (value == 0xffffffff)
286 			continue;
287 		value = pci_cfgregread(bus, device, func, PCIR_INTPIN, 1);
288 
289 		/*
290 		 * See if it uses the pin in question.  Note that the passed
291 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
292 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
293 		 */
294 		if (value != pin + 1)
295 			continue;
296 		value = pci_cfgregread(bus, device, func, PCIR_INTLINE, 1);
297 		if (bootverbose)
298 			printf(
299 		"$PIR: Found matching pin for %d.%d.INT%c at func %d: %d\n",
300 			    bus, device, pin + 'A', func, value);
301 		if (value != PCI_INVALID_IRQ)
302 			return (value);
303 	}
304 	return (PCI_INVALID_IRQ);
305 }
306 
307 /*
308  * Try to initialize IRQ based on this device's IRQ.
309  */
310 static void
311 pci_pir_initial_irqs(struct PIR_entry *entry, struct PIR_intpin *intpin,
312     void *arg)
313 {
314 	struct pci_link *pci_link;
315 	uint8_t irq, pin;
316 
317 	pin = intpin - entry->pe_intpin;
318 	pci_link = pci_pir_find_link(intpin->link);
319 	irq = pci_pir_search_irq(entry->pe_bus, entry->pe_device, pin);
320 	if (irq == PCI_INVALID_IRQ || irq == pci_link->pl_irq)
321 		return;
322 
323 	/* Don't trust any BIOS IRQs greater than 15. */
324 	if (irq >= NUM_ISA_INTERRUPTS) {
325 		printf(
326 	"$PIR: Ignoring invalid BIOS IRQ %d from %d.%d.INT%c for link %#x\n",
327 		    irq, entry->pe_bus, entry->pe_device, pin + 'A',
328 		    pci_link->pl_id);
329 		return;
330 	}
331 
332 	/*
333 	 * If we don't have an IRQ for this link yet, then we trust the
334 	 * BIOS, even if it seems invalid from the $PIR entries.
335 	 */
336 	if (pci_link->pl_irq == PCI_INVALID_IRQ) {
337 		if (!pci_pir_valid_irq(pci_link, irq))
338 			printf(
339 	"$PIR: Using invalid BIOS IRQ %d from %d.%d.INT%c for link %#x\n",
340 			    irq, entry->pe_bus, entry->pe_device, pin + 'A',
341 			    pci_link->pl_id);
342 		pci_link->pl_irq = irq;
343 		pci_link->pl_routed = 1;
344 		return;
345 	}
346 
347 	/*
348 	 * We have an IRQ and it doesn't match the current IRQ for this
349 	 * link.  If the new IRQ is invalid, then warn about it and ignore
350 	 * it.  If the old IRQ is invalid and the new IRQ is valid, then
351 	 * prefer the new IRQ instead.  If both IRQs are valid, then just
352 	 * use the first one.  Note that if we ever get into this situation
353 	 * we are having to guess which setting the BIOS actually routed.
354 	 * Perhaps we should just give up instead.
355 	 */
356 	if (!pci_pir_valid_irq(pci_link, irq)) {
357 		printf(
358 		"$PIR: BIOS IRQ %d for %d.%d.INT%c is not valid for link %#x\n",
359 		    irq, entry->pe_bus, entry->pe_device, pin + 'A',
360 		    pci_link->pl_id);
361 	} else if (!pci_pir_valid_irq(pci_link, pci_link->pl_irq)) {
362 		printf(
363 "$PIR: Preferring valid BIOS IRQ %d from %d.%d.INT%c for link %#x to IRQ %d\n",
364 		    irq, entry->pe_bus, entry->pe_device, pin + 'A',
365 		    pci_link->pl_id, pci_link->pl_irq);
366 		pci_link->pl_irq = irq;
367 		pci_link->pl_routed = 1;
368 	} else
369 		printf(
370 	"$PIR: BIOS IRQ %d for %d.%d.INT%c does not match link %#x irq %d\n",
371 		    irq, entry->pe_bus, entry->pe_device, pin + 'A',
372 		    pci_link->pl_id, pci_link->pl_irq);
373 }
374 
375 /*
376  * Parse $PIR to enumerate link devices and attempt to determine their
377  * initial state.  This could perhaps be cleaner if we had drivers for the
378  * various interrupt routers as they could read the initial IRQ for each
379  * link.
380  */
381 static void
382 pci_pir_parse(void)
383 {
384 	char tunable_buffer[64];
385 	struct pci_link *pci_link;
386 	int i, irq;
387 
388 	/* Only parse once. */
389 	if (pir_parsed)
390 		return;
391 	pir_parsed = 1;
392 
393 	/* Enumerate link devices. */
394 	TAILQ_INIT(&pci_links);
395 	pci_pir_walk_table(pci_pir_create_links, NULL);
396 	if (bootverbose) {
397 		printf("$PIR: Links after initial probe:\n");
398 		pci_pir_dump_links();
399 	}
400 
401 	/* Check for unique IRQ masks. */
402 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
403 		if (pci_link->pl_irqmask != 0 && powerof2(pci_link->pl_irqmask))
404 			pci_link->pl_irq = ffs(pci_link->pl_irqmask) - 1;
405 	}
406 
407 	/*
408 	 * Check to see if the BIOS has already routed any of the links by
409 	 * checking each device connected to each link to see if it has a
410 	 * valid IRQ.
411 	 */
412 	pci_pir_walk_table(pci_pir_initial_irqs, NULL);
413 	if (bootverbose) {
414 		printf("$PIR: Links after initial IRQ discovery:\n");
415 		pci_pir_dump_links();
416 	}
417 
418 	/*
419 	 * Allow the user to override the IRQ for a given link device.  We
420 	 * allow invalid IRQs to be specified but warn about them.  An IRQ
421 	 * of 255 or 0 clears any preset IRQ.
422 	 */
423 	i = 0;
424 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
425 		snprintf(tunable_buffer, sizeof(tunable_buffer),
426 		    "hw.pci.link.%#x.irq", pci_link->pl_id);
427 		if (getenv_int(tunable_buffer, &irq) == 0)
428 			continue;
429 		if (irq == 0)
430 			irq = PCI_INVALID_IRQ;
431 		if (irq != PCI_INVALID_IRQ &&
432 		    !pci_pir_valid_irq(pci_link, irq) && bootverbose)
433 			printf(
434 		"$PIR: Warning, IRQ %d for link %#x is not listed as valid\n",
435 			    irq, pci_link->pl_id);
436 		pci_link->pl_routed = 0;
437 		pci_link->pl_irq = irq;
438 		i = 1;
439 	}
440 	if (bootverbose && i) {
441 		printf("$PIR: Links after tunable overrides:\n");
442 		pci_pir_dump_links();
443 	}
444 
445 	/*
446 	 * Build initial interrupt weights as well as bitmap of "known-good"
447 	 * IRQs that the BIOS has already used for PCI link devices.
448 	 */
449 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
450 		if (!PCI_INTERRUPT_VALID(pci_link->pl_irq))
451 			continue;
452 		pir_bios_irqs |= 1 << pci_link->pl_irq;
453 		pir_interrupt_weight[pci_link->pl_irq] +=
454 		    pci_link->pl_references;
455 	}
456 	if (bootverbose) {
457 		printf("$PIR: IRQs used by BIOS: ");
458 		pci_print_irqmask(pir_bios_irqs);
459 		printf("\n");
460 		printf("$PIR: Interrupt Weights:\n[ ");
461 		for (i = 0; i < NUM_ISA_INTERRUPTS; i++)
462 			printf(" %3d", i);
463 		printf(" ]\n[ ");
464 		for (i = 0; i < NUM_ISA_INTERRUPTS; i++)
465 			printf(" %3d", pir_interrupt_weight[i]);
466 		printf(" ]\n");
467 	}
468 }
469 
470 /*
471  * Use the PCI BIOS to route an interrupt for a given device.
472  *
473  * Input:
474  * AX = PCIBIOS_ROUTE_INTERRUPT
475  * BH = bus
476  * BL = device [7:3] / function [2:0]
477  * CH = IRQ
478  * CL = Interrupt Pin (0x0A = A, ... 0x0D = D)
479  */
480 static int
481 pci_pir_biosroute(int bus, int device, int func, int pin, int irq)
482 {
483 	struct bios_regs args;
484 
485 	args.eax = PCIBIOS_ROUTE_INTERRUPT;
486 	args.ebx = (bus << 8) | (device << 3) | func;
487 	args.ecx = (irq << 8) | (0xa + pin);
488 	return (bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL)));
489 }
490 
491 
492 /*
493  * Route a PCI interrupt using a link device from the $PIR.
494  */
495 int
496 pci_pir_route_interrupt(int bus, int device, int func, int pin)
497 {
498 	struct pci_link_lookup lookup;
499 	struct pci_link *pci_link;
500 	int error, irq;
501 
502 	if (pci_route_table == NULL)
503 		return (PCI_INVALID_IRQ);
504 
505 	/* Lookup link device for this PCI device/pin. */
506 	pci_link = NULL;
507 	lookup.bus = bus;
508 	lookup.device = device;
509 	lookup.pin = pin - 1;
510 	lookup.pci_link_ptr = &pci_link;
511 	pci_pir_walk_table(pci_pir_find_link_handler, &lookup);
512 	if (pci_link == NULL) {
513 		printf("$PIR: No matching entry for %d.%d.INT%c\n", bus,
514 		    device, pin - 1 + 'A');
515 		return (PCI_INVALID_IRQ);
516 	}
517 
518 	/*
519 	 * Pick a new interrupt if we don't have one already.  We look for
520 	 * an interrupt from several different sets.  First, we check the
521 	 * set of PCI only interrupts from the $PIR.  Second, we check the
522 	 * set of known-good interrupts that the BIOS has already used.
523 	 * Lastly, we check the "all possible valid IRQs" set.
524 	 */
525 	if (!PCI_INTERRUPT_VALID(pci_link->pl_irq)) {
526 		irq = pci_pir_choose_irq(pci_link,
527 		    pci_route_table->pt_header.ph_pci_irqs);
528 		if (!PCI_INTERRUPT_VALID(irq))
529 			irq = pci_pir_choose_irq(pci_link, pir_bios_irqs);
530 		if (!PCI_INTERRUPT_VALID(irq))
531 			irq = pci_pir_choose_irq(pci_link,
532 			    pci_irq_override_mask);
533 		if (!PCI_INTERRUPT_VALID(irq)) {
534 			if (bootverbose)
535 				printf(
536 			"$PIR: Failed to route interrupt for %d:%d INT%c\n",
537 				    bus, device, pin - 1 + 'A');
538 			return (PCI_INVALID_IRQ);
539 		}
540 		pci_link->pl_irq = irq;
541 	}
542 
543 	/* Ask the BIOS to route this IRQ if we haven't done so already. */
544 	if (!pci_link->pl_routed) {
545 		error = pci_pir_biosroute(bus, device, func, pin - 1,
546 		    pci_link->pl_irq);
547 
548 		/* Ignore errors when routing a unique interrupt. */
549 		if (error && !powerof2(pci_link->pl_irqmask)) {
550 			printf("$PIR: ROUTE_INTERRUPT failed.\n");
551 			return (PCI_INVALID_IRQ);
552 		}
553 		pci_link->pl_routed = 1;
554 
555 		/* Ensure the interrupt is set to level/low trigger. */
556 		KASSERT(pir_device != NULL, ("missing pir device"));
557 		BUS_CONFIG_INTR(pir_device, pci_link->pl_irq,
558 		    INTR_TRIGGER_LEVEL, INTR_POLARITY_LOW);
559 	}
560 	if (bootverbose)
561 		printf("$PIR: %d:%d INT%c routed to irq %d\n", bus, device,
562 		    pin - 1 + 'A', pci_link->pl_irq);
563 	return (pci_link->pl_irq);
564 }
565 
566 /*
567  * Try to pick an interrupt for the specified link from the interrupts
568  * set in the mask.
569  */
570 static int
571 pci_pir_choose_irq(struct pci_link *pci_link, int irqmask)
572 {
573 	int i, irq, realmask;
574 
575 	/* XXX: Need to have a #define of known bad IRQs to also mask out? */
576 	realmask = pci_link->pl_irqmask & irqmask;
577 	if (realmask == 0)
578 		return (PCI_INVALID_IRQ);
579 
580 	/* Find IRQ with lowest weight. */
581 	irq = PCI_INVALID_IRQ;
582 	for (i = 0; i < NUM_ISA_INTERRUPTS; i++) {
583 		if (!(realmask & 1 << i))
584 			continue;
585 		if (irq == PCI_INVALID_IRQ ||
586 		    pir_interrupt_weight[i] < pir_interrupt_weight[irq])
587 			irq = i;
588 	}
589 	if (bootverbose && PCI_INTERRUPT_VALID(irq)) {
590 		printf("$PIR: Found IRQ %d for link %#x from ", irq,
591 		    pci_link->pl_id);
592 		pci_print_irqmask(realmask);
593 		printf("\n");
594 	}
595 	return (irq);
596 }
597 
598 static void
599 pci_print_irqmask(u_int16_t irqs)
600 {
601 	int i, first;
602 
603 	if (irqs == 0) {
604 		printf("none");
605 		return;
606 	}
607 	first = 1;
608 	for (i = 0; i < 16; i++, irqs >>= 1)
609 		if (irqs & 1) {
610 			if (!first)
611 				printf(" ");
612 			else
613 				first = 0;
614 			printf("%d", i);
615 		}
616 }
617 
618 /*
619  * Display link devices.
620  */
621 static void
622 pci_pir_dump_links(void)
623 {
624 	struct pci_link *pci_link;
625 
626 	printf("Link  IRQ  Rtd  Ref  IRQs\n");
627 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
628 		printf("%#4x  %3d   %c   %3d  ", pci_link->pl_id,
629 		    pci_link->pl_irq, pci_link->pl_routed ? 'Y' : 'N',
630 		    pci_link->pl_references);
631 		pci_print_irqmask(pci_link->pl_irqmask);
632 		printf("\n");
633 	}
634 }
635 
636 /*
637  * See if any interrupts for a given PCI bus are routed in the PIR.  Don't
638  * even bother looking if the BIOS doesn't support routing anyways.  If we
639  * are probing a PCI-PCI bridge, then require_parse will be true and we should
640  * only succeed if a host-PCI bridge has already attached and parsed the PIR.
641  */
642 int
643 pci_pir_probe(int bus, int require_parse)
644 {
645 	int i;
646 
647 	if (pci_route_table == NULL || (require_parse && !pir_parsed))
648 		return (0);
649 	for (i = 0; i < pci_route_count; i++)
650 		if (pci_route_table->pt_entry[i].pe_bus == bus)
651 			return (1);
652 	return (0);
653 }
654 
655 /*
656  * The driver for the new-bus psuedo device pir0 for the $PIR table.
657  */
658 
659 static int
660 pir_probe(device_t dev)
661 {
662 	char buf[64];
663 
664 	snprintf(buf, sizeof(buf), "PCI Interrupt Routing Table: %d Entries",
665 	    pci_route_count);
666 	device_set_desc_copy(dev, buf);
667 	return (0);
668 }
669 
670 static int
671 pir_attach(device_t dev)
672 {
673 
674 	pci_pir_parse();
675 	KASSERT(pir_device == NULL, ("Multiple pir devices"));
676 	pir_device = dev;
677 	return (0);
678 }
679 
680 static void
681 pir_resume_find_device(struct PIR_entry *entry, struct PIR_intpin *intpin,
682     void *arg)
683 {
684 	struct pci_dev_lookup *pd;
685 
686 	pd = (struct pci_dev_lookup *)arg;
687 	if (intpin->link != pd->link || pd->bus != -1)
688 		return;
689 	pd->bus = entry->pe_bus;
690 	pd->device = entry->pe_device;
691 	pd->pin = intpin - entry->pe_intpin;
692 }
693 
694 static int
695 pir_resume(device_t dev)
696 {
697 	struct pci_dev_lookup pd;
698 	struct pci_link *pci_link;
699 	int error;
700 
701 	/* Ask the BIOS to re-route each link that was already routed. */
702 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
703 		if (!PCI_INTERRUPT_VALID(pci_link->pl_irq)) {
704 			KASSERT(!pci_link->pl_routed,
705 			    ("link %#x is routed but has invalid PCI IRQ",
706 			    pci_link->pl_id));
707 			continue;
708 		}
709 		if (pci_link->pl_routed) {
710 			pd.bus = -1;
711 			pd.link = pci_link->pl_id;
712 			pci_pir_walk_table(pir_resume_find_device, &pd);
713 			KASSERT(pd.bus != -1,
714 		("did not find matching entry for link %#x in the $PIR table",
715 			    pci_link->pl_id));
716 			if (bootverbose)
717 				device_printf(dev,
718 			    "Using %d.%d.INT%c to route link %#x to IRQ %d\n",
719 				    pd.bus, pd.device, pd.pin + 'A',
720 				    pci_link->pl_id, pci_link->pl_irq);
721 			error = pci_pir_biosroute(pd.bus, pd.device, 0, pd.pin,
722 			    pci_link->pl_irq);
723 			if (error)
724 				device_printf(dev,
725 			    "ROUTE_INTERRUPT on resume for link %#x failed.\n",
726 				    pci_link->pl_id);
727 		}
728 	}
729 	return (0);
730 }
731 
732 static device_method_t pir_methods[] = {
733 	/* Device interface */
734 	DEVMETHOD(device_probe,		pir_probe),
735 	DEVMETHOD(device_attach,	pir_attach),
736 	DEVMETHOD(device_resume,	pir_resume),
737 
738 	{ 0, 0 }
739 };
740 
741 static driver_t pir_driver = {
742 	"pir",
743 	pir_methods,
744 	1,
745 };
746 
747 static devclass_t pir_devclass;
748 
749 DRIVER_MODULE(pir, legacy, pir_driver, pir_devclass, 0, 0);
750