xref: /freebsd/sys/i386/pci/pci_pir.c (revision af3b2549c4ba2ef00a7cbb4cb6836598bf0aefbe)
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 SYSCTL_INT(_hw_pci, OID_AUTO, irq_override_mask, CTLFLAG_RDTUN,
121     &pci_irq_override_mask, PCI_IRQ_OVERRIDE_MASK,
122     "Mask of allowed irqs to try to route when it has no good clue about\n"
123     "which irqs it should use.");
124 
125 /*
126  * Look for the interrupt routing table.
127  *
128  * We use PCI BIOS's PIR table if it's available. $PIR is the standard way
129  * to do this.  Sadly, some machines are not standards conforming and have
130  * _PIR instead.  We shrug and cope by looking for both.
131  */
132 void
133 pci_pir_open(void)
134 {
135 	struct PIR_table *pt;
136 	uint32_t sigaddr;
137 	int i;
138 	uint8_t ck, *cv;
139 
140 #ifdef XEN
141 	return;
142 #else
143 	/* Don't try if we've already found a table. */
144 	if (pci_route_table != NULL)
145 		return;
146 
147 	/* Look for $PIR and then _PIR. */
148 	sigaddr = bios_sigsearch(0, "$PIR", 4, 16, 0);
149 	if (sigaddr == 0)
150 		sigaddr = bios_sigsearch(0, "_PIR", 4, 16, 0);
151 	if (sigaddr == 0)
152 		return;
153 #endif
154 	/* If we found something, check the checksum and length. */
155 	/* XXX - Use pmap_mapdev()? */
156 	pt = (struct PIR_table *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
157 	if (pt->pt_header.ph_length <= sizeof(struct PIR_header))
158 		return;
159 	for (cv = (u_int8_t *)pt, ck = 0, i = 0;
160 	     i < (pt->pt_header.ph_length); i++)
161 		ck += cv[i];
162 	if (ck != 0)
163 		return;
164 
165 	/* Ok, we've got a valid table. */
166 	pci_route_table = pt;
167 	pci_route_count = (pt->pt_header.ph_length -
168 	    sizeof(struct PIR_header)) /
169 	    sizeof(struct PIR_entry);
170 }
171 
172 /*
173  * Find the pci_link structure for a given link ID.
174  */
175 static struct pci_link *
176 pci_pir_find_link(uint8_t link_id)
177 {
178 	struct pci_link *pci_link;
179 
180 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
181 		if (pci_link->pl_id == link_id)
182 			return (pci_link);
183 	}
184 	return (NULL);
185 }
186 
187 /*
188  * Find the link device associated with a PCI device in the table.
189  */
190 static void
191 pci_pir_find_link_handler(struct PIR_entry *entry, struct PIR_intpin *intpin,
192     void *arg)
193 {
194 	struct pci_link_lookup *lookup;
195 
196 	lookup = (struct pci_link_lookup *)arg;
197 	if (entry->pe_bus == lookup->bus &&
198 	    entry->pe_device == lookup->device &&
199 	    intpin - entry->pe_intpin == lookup->pin)
200 		*lookup->pci_link_ptr = pci_pir_find_link(intpin->link);
201 }
202 
203 /*
204  * Check to see if a possible IRQ setting is valid.
205  */
206 static int
207 pci_pir_valid_irq(struct pci_link *pci_link, int irq)
208 {
209 
210 	if (!PCI_INTERRUPT_VALID(irq))
211 		return (0);
212 	return (pci_link->pl_irqmask & (1 << irq));
213 }
214 
215 /*
216  * Walk the $PIR executing the worker function for each valid intpin entry
217  * in the table.  The handler is passed a pointer to both the entry and
218  * the intpin in the entry.
219  */
220 static void
221 pci_pir_walk_table(pir_entry_handler *handler, void *arg)
222 {
223 	struct PIR_entry *entry;
224 	struct PIR_intpin *intpin;
225 	int i, pin;
226 
227 	entry = &pci_route_table->pt_entry[0];
228 	for (i = 0; i < pci_route_count; i++, entry++) {
229 		intpin = &entry->pe_intpin[0];
230 		for (pin = 0; pin < 4; pin++, intpin++)
231 			if (intpin->link != 0)
232 				handler(entry, intpin, arg);
233 	}
234 }
235 
236 static void
237 pci_pir_create_links(struct PIR_entry *entry, struct PIR_intpin *intpin,
238     void *arg)
239 {
240 	struct pci_link *pci_link;
241 
242 	pci_link = pci_pir_find_link(intpin->link);
243 	if (pci_link != NULL) {
244 		pci_link->pl_references++;
245 		if (intpin->irqs != pci_link->pl_irqmask) {
246 			if (bootverbose)
247 				printf(
248 	"$PIR: Entry %d.%d.INT%c has different mask for link %#x, merging\n",
249 				    entry->pe_bus, entry->pe_device,
250 				    (intpin - entry->pe_intpin) + 'A',
251 				    pci_link->pl_id);
252 			pci_link->pl_irqmask &= intpin->irqs;
253 		}
254 	} else {
255 		pci_link = malloc(sizeof(struct pci_link), M_PIR, M_WAITOK);
256 		pci_link->pl_id = intpin->link;
257 		pci_link->pl_irqmask = intpin->irqs;
258 		pci_link->pl_irq = PCI_INVALID_IRQ;
259 		pci_link->pl_references = 1;
260 		pci_link->pl_routed = 0;
261 		TAILQ_INSERT_TAIL(&pci_links, pci_link, pl_links);
262 	}
263 }
264 
265 /*
266  * Look to see if any of the function on the PCI device at bus/device have
267  * an interrupt routed to intpin 'pin' by the BIOS.
268  */
269 static uint8_t
270 pci_pir_search_irq(int bus, int device, int pin)
271 {
272 	uint32_t value;
273 	uint8_t func, maxfunc;
274 
275 	/* See if we have a valid device at function 0. */
276 	value = pci_cfgregread(bus, device, 0, PCIR_HDRTYPE, 1);
277 	if ((value & PCIM_HDRTYPE) > PCI_MAXHDRTYPE)
278 		return (PCI_INVALID_IRQ);
279 	if (value & PCIM_MFDEV)
280 		maxfunc = PCI_FUNCMAX;
281 	else
282 		maxfunc = 0;
283 
284 	/* Scan all possible functions at this device. */
285 	for (func = 0; func <= maxfunc; func++) {
286 		value = pci_cfgregread(bus, device, func, PCIR_DEVVENDOR, 4);
287 		if (value == 0xffffffff)
288 			continue;
289 		value = pci_cfgregread(bus, device, func, PCIR_INTPIN, 1);
290 
291 		/*
292 		 * See if it uses the pin in question.  Note that the passed
293 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
294 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
295 		 */
296 		if (value != pin + 1)
297 			continue;
298 		value = pci_cfgregread(bus, device, func, PCIR_INTLINE, 1);
299 		if (bootverbose)
300 			printf(
301 		"$PIR: Found matching pin for %d.%d.INT%c at func %d: %d\n",
302 			    bus, device, pin + 'A', func, value);
303 		if (value != PCI_INVALID_IRQ)
304 			return (value);
305 	}
306 	return (PCI_INVALID_IRQ);
307 }
308 
309 /*
310  * Try to initialize IRQ based on this device's IRQ.
311  */
312 static void
313 pci_pir_initial_irqs(struct PIR_entry *entry, struct PIR_intpin *intpin,
314     void *arg)
315 {
316 	struct pci_link *pci_link;
317 	uint8_t irq, pin;
318 
319 	pin = intpin - entry->pe_intpin;
320 	pci_link = pci_pir_find_link(intpin->link);
321 	irq = pci_pir_search_irq(entry->pe_bus, entry->pe_device, pin);
322 	if (irq == PCI_INVALID_IRQ || irq == pci_link->pl_irq)
323 		return;
324 
325 	/* Don't trust any BIOS IRQs greater than 15. */
326 	if (irq >= NUM_ISA_INTERRUPTS) {
327 		printf(
328 	"$PIR: Ignoring invalid BIOS IRQ %d from %d.%d.INT%c for link %#x\n",
329 		    irq, entry->pe_bus, entry->pe_device, pin + 'A',
330 		    pci_link->pl_id);
331 		return;
332 	}
333 
334 	/*
335 	 * If we don't have an IRQ for this link yet, then we trust the
336 	 * BIOS, even if it seems invalid from the $PIR entries.
337 	 */
338 	if (pci_link->pl_irq == PCI_INVALID_IRQ) {
339 		if (!pci_pir_valid_irq(pci_link, irq))
340 			printf(
341 	"$PIR: Using invalid BIOS IRQ %d from %d.%d.INT%c for link %#x\n",
342 			    irq, entry->pe_bus, entry->pe_device, pin + 'A',
343 			    pci_link->pl_id);
344 		pci_link->pl_irq = irq;
345 		pci_link->pl_routed = 1;
346 		return;
347 	}
348 
349 	/*
350 	 * We have an IRQ and it doesn't match the current IRQ for this
351 	 * link.  If the new IRQ is invalid, then warn about it and ignore
352 	 * it.  If the old IRQ is invalid and the new IRQ is valid, then
353 	 * prefer the new IRQ instead.  If both IRQs are valid, then just
354 	 * use the first one.  Note that if we ever get into this situation
355 	 * we are having to guess which setting the BIOS actually routed.
356 	 * Perhaps we should just give up instead.
357 	 */
358 	if (!pci_pir_valid_irq(pci_link, irq)) {
359 		printf(
360 		"$PIR: BIOS IRQ %d for %d.%d.INT%c is not valid for link %#x\n",
361 		    irq, entry->pe_bus, entry->pe_device, pin + 'A',
362 		    pci_link->pl_id);
363 	} else if (!pci_pir_valid_irq(pci_link, pci_link->pl_irq)) {
364 		printf(
365 "$PIR: Preferring valid BIOS IRQ %d from %d.%d.INT%c for link %#x to IRQ %d\n",
366 		    irq, entry->pe_bus, entry->pe_device, pin + 'A',
367 		    pci_link->pl_id, pci_link->pl_irq);
368 		pci_link->pl_irq = irq;
369 		pci_link->pl_routed = 1;
370 	} else
371 		printf(
372 	"$PIR: BIOS IRQ %d for %d.%d.INT%c does not match link %#x irq %d\n",
373 		    irq, entry->pe_bus, entry->pe_device, pin + 'A',
374 		    pci_link->pl_id, pci_link->pl_irq);
375 }
376 
377 /*
378  * Parse $PIR to enumerate link devices and attempt to determine their
379  * initial state.  This could perhaps be cleaner if we had drivers for the
380  * various interrupt routers as they could read the initial IRQ for each
381  * link.
382  */
383 static void
384 pci_pir_parse(void)
385 {
386 	char tunable_buffer[64];
387 	struct pci_link *pci_link;
388 	int i, irq;
389 
390 	/* Only parse once. */
391 	if (pir_parsed)
392 		return;
393 	pir_parsed = 1;
394 
395 	/* Enumerate link devices. */
396 	TAILQ_INIT(&pci_links);
397 	pci_pir_walk_table(pci_pir_create_links, NULL);
398 	if (bootverbose) {
399 		printf("$PIR: Links after initial probe:\n");
400 		pci_pir_dump_links();
401 	}
402 
403 	/*
404 	 * Check to see if the BIOS has already routed any of the links by
405 	 * checking each device connected to each link to see if it has a
406 	 * valid IRQ.
407 	 */
408 	pci_pir_walk_table(pci_pir_initial_irqs, NULL);
409 	if (bootverbose) {
410 		printf("$PIR: Links after initial IRQ discovery:\n");
411 		pci_pir_dump_links();
412 	}
413 
414 	/*
415 	 * Allow the user to override the IRQ for a given link device.  We
416 	 * allow invalid IRQs to be specified but warn about them.  An IRQ
417 	 * of 255 or 0 clears any preset IRQ.
418 	 */
419 	i = 0;
420 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
421 		snprintf(tunable_buffer, sizeof(tunable_buffer),
422 		    "hw.pci.link.%#x.irq", pci_link->pl_id);
423 		if (getenv_int(tunable_buffer, &irq) == 0)
424 			continue;
425 		if (irq == 0)
426 			irq = PCI_INVALID_IRQ;
427 		if (irq != PCI_INVALID_IRQ &&
428 		    !pci_pir_valid_irq(pci_link, irq) && bootverbose)
429 			printf(
430 		"$PIR: Warning, IRQ %d for link %#x is not listed as valid\n",
431 			    irq, pci_link->pl_id);
432 		pci_link->pl_routed = 0;
433 		pci_link->pl_irq = irq;
434 		i = 1;
435 	}
436 	if (bootverbose && i) {
437 		printf("$PIR: Links after tunable overrides:\n");
438 		pci_pir_dump_links();
439 	}
440 
441 	/*
442 	 * Build initial interrupt weights as well as bitmap of "known-good"
443 	 * IRQs that the BIOS has already used for PCI link devices.
444 	 */
445 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
446 		if (!PCI_INTERRUPT_VALID(pci_link->pl_irq))
447 			continue;
448 		pir_bios_irqs |= 1 << pci_link->pl_irq;
449 		pir_interrupt_weight[pci_link->pl_irq] +=
450 		    pci_link->pl_references;
451 	}
452 	if (bootverbose) {
453 		printf("$PIR: IRQs used by BIOS: ");
454 		pci_print_irqmask(pir_bios_irqs);
455 		printf("\n");
456 		printf("$PIR: Interrupt Weights:\n[ ");
457 		for (i = 0; i < NUM_ISA_INTERRUPTS; i++)
458 			printf(" %3d", i);
459 		printf(" ]\n[ ");
460 		for (i = 0; i < NUM_ISA_INTERRUPTS; i++)
461 			printf(" %3d", pir_interrupt_weight[i]);
462 		printf(" ]\n");
463 	}
464 }
465 
466 /*
467  * Use the PCI BIOS to route an interrupt for a given device.
468  *
469  * Input:
470  * AX = PCIBIOS_ROUTE_INTERRUPT
471  * BH = bus
472  * BL = device [7:3] / function [2:0]
473  * CH = IRQ
474  * CL = Interrupt Pin (0x0A = A, ... 0x0D = D)
475  */
476 static int
477 pci_pir_biosroute(int bus, int device, int func, int pin, int irq)
478 {
479 	struct bios_regs args;
480 
481 	args.eax = PCIBIOS_ROUTE_INTERRUPT;
482 	args.ebx = (bus << 8) | (device << 3) | func;
483 	args.ecx = (irq << 8) | (0xa + pin);
484 #ifdef XEN
485 	return (0);
486 #else
487 	return (bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL)));
488 #endif
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
520 	 * for an interrupt from several different sets.  First, if
521 	 * this link only has one valid IRQ, use that.  Second, we
522 	 * check the set of PCI only interrupts from the $PIR.  Third,
523 	 * we check the set of known-good interrupts that the BIOS has
524 	 * already used.  Lastly, we check the "all possible valid
525 	 * IRQs" set.
526 	 */
527 	if (!PCI_INTERRUPT_VALID(pci_link->pl_irq)) {
528 		if (pci_link->pl_irqmask != 0 && powerof2(pci_link->pl_irqmask))
529 			irq = ffs(pci_link->pl_irqmask) - 1;
530 		else
531 			irq = pci_pir_choose_irq(pci_link,
532 			    pci_route_table->pt_header.ph_pci_irqs);
533 		if (!PCI_INTERRUPT_VALID(irq))
534 			irq = pci_pir_choose_irq(pci_link, pir_bios_irqs);
535 		if (!PCI_INTERRUPT_VALID(irq))
536 			irq = pci_pir_choose_irq(pci_link,
537 			    pci_irq_override_mask);
538 		if (!PCI_INTERRUPT_VALID(irq)) {
539 			if (bootverbose)
540 				printf(
541 			"$PIR: Failed to route interrupt for %d:%d INT%c\n",
542 				    bus, device, pin - 1 + 'A');
543 			return (PCI_INVALID_IRQ);
544 		}
545 		pci_link->pl_irq = irq;
546 	}
547 
548 	/* Ask the BIOS to route this IRQ if we haven't done so already. */
549 	if (!pci_link->pl_routed) {
550 		error = pci_pir_biosroute(bus, device, func, pin - 1,
551 		    pci_link->pl_irq);
552 
553 		/* Ignore errors when routing a unique interrupt. */
554 		if (error && !powerof2(pci_link->pl_irqmask)) {
555 			printf("$PIR: ROUTE_INTERRUPT failed.\n");
556 			return (PCI_INVALID_IRQ);
557 		}
558 		pci_link->pl_routed = 1;
559 
560 		/* Ensure the interrupt is set to level/low trigger. */
561 		KASSERT(pir_device != NULL, ("missing pir device"));
562 		BUS_CONFIG_INTR(pir_device, pci_link->pl_irq,
563 		    INTR_TRIGGER_LEVEL, INTR_POLARITY_LOW);
564 	}
565 	if (bootverbose)
566 		printf("$PIR: %d:%d INT%c routed to irq %d\n", bus, device,
567 		    pin - 1 + 'A', pci_link->pl_irq);
568 	return (pci_link->pl_irq);
569 }
570 
571 /*
572  * Try to pick an interrupt for the specified link from the interrupts
573  * set in the mask.
574  */
575 static int
576 pci_pir_choose_irq(struct pci_link *pci_link, int irqmask)
577 {
578 	int i, irq, realmask;
579 
580 	/* XXX: Need to have a #define of known bad IRQs to also mask out? */
581 	realmask = pci_link->pl_irqmask & irqmask;
582 	if (realmask == 0)
583 		return (PCI_INVALID_IRQ);
584 
585 	/* Find IRQ with lowest weight. */
586 	irq = PCI_INVALID_IRQ;
587 	for (i = 0; i < NUM_ISA_INTERRUPTS; i++) {
588 		if (!(realmask & 1 << i))
589 			continue;
590 		if (irq == PCI_INVALID_IRQ ||
591 		    pir_interrupt_weight[i] < pir_interrupt_weight[irq])
592 			irq = i;
593 	}
594 	if (bootverbose && PCI_INTERRUPT_VALID(irq)) {
595 		printf("$PIR: Found IRQ %d for link %#x from ", irq,
596 		    pci_link->pl_id);
597 		pci_print_irqmask(realmask);
598 		printf("\n");
599 	}
600 	return (irq);
601 }
602 
603 static void
604 pci_print_irqmask(u_int16_t irqs)
605 {
606 	int i, first;
607 
608 	if (irqs == 0) {
609 		printf("none");
610 		return;
611 	}
612 	first = 1;
613 	for (i = 0; i < 16; i++, irqs >>= 1)
614 		if (irqs & 1) {
615 			if (!first)
616 				printf(" ");
617 			else
618 				first = 0;
619 			printf("%d", i);
620 		}
621 }
622 
623 /*
624  * Display link devices.
625  */
626 static void
627 pci_pir_dump_links(void)
628 {
629 	struct pci_link *pci_link;
630 
631 	printf("Link  IRQ  Rtd  Ref  IRQs\n");
632 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
633 		printf("%#4x  %3d   %c   %3d  ", pci_link->pl_id,
634 		    pci_link->pl_irq, pci_link->pl_routed ? 'Y' : 'N',
635 		    pci_link->pl_references);
636 		pci_print_irqmask(pci_link->pl_irqmask);
637 		printf("\n");
638 	}
639 }
640 
641 /*
642  * See if any interrupts for a given PCI bus are routed in the PIR.  Don't
643  * even bother looking if the BIOS doesn't support routing anyways.  If we
644  * are probing a PCI-PCI bridge, then require_parse will be true and we should
645  * only succeed if a host-PCI bridge has already attached and parsed the PIR.
646  */
647 int
648 pci_pir_probe(int bus, int require_parse)
649 {
650 	int i;
651 
652 	if (pci_route_table == NULL || (require_parse && !pir_parsed))
653 		return (0);
654 	for (i = 0; i < pci_route_count; i++)
655 		if (pci_route_table->pt_entry[i].pe_bus == bus)
656 			return (1);
657 	return (0);
658 }
659 
660 /*
661  * The driver for the new-bus psuedo device pir0 for the $PIR table.
662  */
663 
664 static int
665 pir_probe(device_t dev)
666 {
667 	char buf[64];
668 
669 	snprintf(buf, sizeof(buf), "PCI Interrupt Routing Table: %d Entries",
670 	    pci_route_count);
671 	device_set_desc_copy(dev, buf);
672 	return (0);
673 }
674 
675 static int
676 pir_attach(device_t dev)
677 {
678 
679 	pci_pir_parse();
680 	KASSERT(pir_device == NULL, ("Multiple pir devices"));
681 	pir_device = dev;
682 	return (0);
683 }
684 
685 static void
686 pir_resume_find_device(struct PIR_entry *entry, struct PIR_intpin *intpin,
687     void *arg)
688 {
689 	struct pci_dev_lookup *pd;
690 
691 	pd = (struct pci_dev_lookup *)arg;
692 	if (intpin->link != pd->link || pd->bus != -1)
693 		return;
694 	pd->bus = entry->pe_bus;
695 	pd->device = entry->pe_device;
696 	pd->pin = intpin - entry->pe_intpin;
697 }
698 
699 static int
700 pir_resume(device_t dev)
701 {
702 	struct pci_dev_lookup pd;
703 	struct pci_link *pci_link;
704 	int error;
705 
706 	/* Ask the BIOS to re-route each link that was already routed. */
707 	TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
708 		if (!PCI_INTERRUPT_VALID(pci_link->pl_irq)) {
709 			KASSERT(!pci_link->pl_routed,
710 			    ("link %#x is routed but has invalid PCI IRQ",
711 			    pci_link->pl_id));
712 			continue;
713 		}
714 		if (pci_link->pl_routed) {
715 			pd.bus = -1;
716 			pd.link = pci_link->pl_id;
717 			pci_pir_walk_table(pir_resume_find_device, &pd);
718 			KASSERT(pd.bus != -1,
719 		("did not find matching entry for link %#x in the $PIR table",
720 			    pci_link->pl_id));
721 			if (bootverbose)
722 				device_printf(dev,
723 			    "Using %d.%d.INT%c to route link %#x to IRQ %d\n",
724 				    pd.bus, pd.device, pd.pin + 'A',
725 				    pci_link->pl_id, pci_link->pl_irq);
726 			error = pci_pir_biosroute(pd.bus, pd.device, 0, pd.pin,
727 			    pci_link->pl_irq);
728 			if (error)
729 				device_printf(dev,
730 			    "ROUTE_INTERRUPT on resume for link %#x failed.\n",
731 				    pci_link->pl_id);
732 		}
733 	}
734 	return (0);
735 }
736 
737 static device_method_t pir_methods[] = {
738 	/* Device interface */
739 	DEVMETHOD(device_probe,		pir_probe),
740 	DEVMETHOD(device_attach,	pir_attach),
741 	DEVMETHOD(device_resume,	pir_resume),
742 
743 	{ 0, 0 }
744 };
745 
746 static driver_t pir_driver = {
747 	"pir",
748 	pir_methods,
749 	1,
750 };
751 
752 static devclass_t pir_devclass;
753 
754 DRIVER_MODULE(pir, legacy, pir_driver, pir_devclass, 0, 0);
755