xref: /dragonfly/sys/dev/acpica/acpi_pci_link.c (revision 5062ee70)
1 /*
2  * Copyright (c) 2002 Mitsuru IWASAKI <iwasaki@jp.kfreebsd.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD: src/sys/dev/acpica/acpi_pci_link.c,v 1.65 2013/04/23 00:40:24 svnexp Exp $
27  */
28 
29 #include "opt_acpi.h"
30 #include <sys/param.h>
31 #include <sys/bus.h>
32 #include <sys/kernel.h>
33 #include <sys/limits.h>
34 #include <sys/malloc.h>
35 #include <sys/module.h>
36 
37 #include "acpi.h"
38 #include <dev/acpica/acpivar.h>
39 #include <dev/acpica/acpi_pcibvar.h>
40 #include <dev/acpica/acpi_sci_var.h>
41 
42 #include <bus/pci/pci_cfgreg.h>
43 #include <bus/pci/pcireg.h>
44 #include <bus/pci/pcivar.h>
45 #include "pcib_if.h"
46 
47 /* Hooks for the ACPICA debugging infrastructure. */
48 #define _COMPONENT	ACPI_BUS
49 ACPI_MODULE_NAME("PCI_LINK")
50 
51 ACPI_SERIAL_DECL(pci_link, "ACPI PCI link");
52 
53 #define NUM_ISA_INTERRUPTS	16
54 #define NUM_ACPI_INTERRUPTS	256
55 
56 /*
57  * An ACPI PCI link device may contain multiple links.  Each link has its
58  * own ACPI resource.  _PRT entries specify which link is being used via
59  * the Source Index.
60  *
61  * XXX: A note about Source Indices and DPFs:  Currently we assume that
62  * the DPF start and end tags are not counted towards the index that
63  * Source Index corresponds to.  Also, we assume that when DPFs are in use
64  * they various sets overlap in terms of Indices.  Here's an example
65  * resource list indicating these assumptions:
66  *
67  * Resource		Index
68  * --------		-----
69  * I/O Port		0
70  * Start DPF		-
71  * IRQ			1
72  * MemIO		2
73  * Start DPF		-
74  * IRQ			1
75  * MemIO		2
76  * End DPF		-
77  * DMA Channel		3
78  *
79  * The XXX is because I'm not sure if this is a valid assumption to make.
80  */
81 
82 /* States during DPF processing. */
83 #define	DPF_OUTSIDE	0
84 #define	DPF_FIRST	1
85 #define	DPF_IGNORE	2
86 
87 struct link;
88 
89 struct acpi_pci_link_softc {
90 	int	pl_num_links;
91 	int	pl_crs_bad;
92 	struct link *pl_links;
93 	device_t pl_dev;
94 };
95 
96 struct link {
97 	struct acpi_pci_link_softc *l_sc;
98 	uint8_t	l_bios_irq;
99 	uint8_t	l_irq;
100 	uint8_t	l_initial_irq;
101 	UINT32	l_crs_type;
102 	int	l_res_index;
103 	int	l_num_irqs;
104 	int	*l_irqs;
105 	int	l_references;
106 	int	l_routed:1;
107 	int	l_isa_irq:1;
108 	ACPI_RESOURCE l_prs_template;
109 };
110 
111 struct link_count_request {
112 	int	in_dpf;
113 	int	count;
114 };
115 
116 struct link_res_request {
117 	struct acpi_pci_link_softc *sc;
118 	int	in_dpf;
119 	int	res_index;
120 	int	link_index;
121 };
122 
123 static MALLOC_DEFINE(M_PCI_LINK, "pci_link", "ACPI PCI Link structures");
124 
125 static int pci_link_interrupt_weights[NUM_ACPI_INTERRUPTS];
126 static int pci_link_bios_isa_irqs;
127 
128 static char *pci_link_ids[] = { "PNP0C0F", NULL };
129 
130 /*
131  * Fetch the short name associated with an ACPI handle and save it in the
132  * passed in buffer.
133  */
134 static ACPI_STATUS
135 acpi_short_name(ACPI_HANDLE handle, char *buffer, size_t buflen)
136 {
137 	ACPI_BUFFER buf;
138 
139 	buf.Length = buflen;
140 	buf.Pointer = buffer;
141 	return (AcpiGetName(handle, ACPI_SINGLE_NAME, &buf));
142 }
143 
144 static int
145 acpi_pci_link_probe(device_t dev)
146 {
147 	char descr[28], name[12];
148 
149 	/*
150 	 * We explicitly do not check _STA since not all systems set it to
151 	 * sensible values.
152 	 */
153 	if (acpi_disabled("pci_link") ||
154 	    ACPI_ID_PROBE(device_get_parent(dev), dev, pci_link_ids) == NULL)
155 		return (ENXIO);
156 
157 	if (ACPI_SUCCESS(acpi_short_name(acpi_get_handle(dev), name,
158 	    sizeof(name)))) {
159 		ksnprintf(descr, sizeof(descr), "ACPI PCI Link %s", name);
160 		device_set_desc_copy(dev, descr);
161 	} else
162 		device_set_desc(dev, "ACPI PCI Link");
163 	device_quiet(dev);
164 	return (0);
165 }
166 
167 static ACPI_STATUS
168 acpi_count_irq_resources(ACPI_RESOURCE *res, void *context)
169 {
170 	struct link_count_request *req;
171 
172 	req = (struct link_count_request *)context;
173 	switch (res->Type) {
174 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
175 		switch (req->in_dpf) {
176 		case DPF_OUTSIDE:
177 			/* We've started the first DPF. */
178 			req->in_dpf = DPF_FIRST;
179 			break;
180 		case DPF_FIRST:
181 			/* We've started the second DPF. */
182 			req->in_dpf = DPF_IGNORE;
183 			break;
184 		}
185 		break;
186 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
187 		/* We are finished with DPF parsing. */
188 		KASSERT(req->in_dpf != DPF_OUTSIDE,
189 		    ("%s: end dpf when not parsing a dpf", __func__));
190 		req->in_dpf = DPF_OUTSIDE;
191 		break;
192 	case ACPI_RESOURCE_TYPE_IRQ:
193 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
194 		/*
195 		 * Don't count resources if we are in a DPF set that we are
196 		 * ignoring.
197 		 */
198 		if (req->in_dpf != DPF_IGNORE)
199 			req->count++;
200 	}
201 	return (AE_OK);
202 }
203 
204 static ACPI_STATUS
205 link_add_crs(ACPI_RESOURCE *res, void *context)
206 {
207 	struct link_res_request *req;
208 	struct link *link;
209 
210 	ACPI_SERIAL_ASSERT(pci_link);
211 	req = (struct link_res_request *)context;
212 	switch (res->Type) {
213 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
214 		switch (req->in_dpf) {
215 		case DPF_OUTSIDE:
216 			/* We've started the first DPF. */
217 			req->in_dpf = DPF_FIRST;
218 			break;
219 		case DPF_FIRST:
220 			/* We've started the second DPF. */
221 			panic(
222 		"%s: Multiple dependent functions within a current resource",
223 			    __func__);
224 			break;
225 		}
226 		break;
227 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
228 		/* We are finished with DPF parsing. */
229 		KASSERT(req->in_dpf != DPF_OUTSIDE,
230 		    ("%s: end dpf when not parsing a dpf", __func__));
231 		req->in_dpf = DPF_OUTSIDE;
232 		break;
233 	case ACPI_RESOURCE_TYPE_IRQ:
234 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
235 		KASSERT(req->link_index < req->sc->pl_num_links,
236 		    ("%s: array boundary violation", __func__));
237 		link = &req->sc->pl_links[req->link_index];
238 		link->l_res_index = req->res_index;
239 		link->l_crs_type = res->Type;
240 		req->link_index++;
241 		req->res_index++;
242 
243 		/*
244 		 * Only use the current value if there's one IRQ.  Some
245 		 * systems return multiple IRQs (which is nonsense for _CRS)
246 		 * when the link hasn't been programmed.
247 		 */
248 		if (res->Type == ACPI_RESOURCE_TYPE_IRQ) {
249 			if (res->Data.Irq.InterruptCount == 1)
250 				link->l_irq = res->Data.Irq.Interrupts[0];
251 		} else if (res->Data.ExtendedIrq.InterruptCount == 1)
252 			link->l_irq = res->Data.ExtendedIrq.Interrupts[0];
253 
254 		/*
255 		 * An IRQ of zero means that the link isn't routed.
256 		 */
257 		if (link->l_irq == 0)
258 			link->l_irq = PCI_INVALID_IRQ;
259 		break;
260 	default:
261 		req->res_index++;
262 	}
263 	return (AE_OK);
264 }
265 
266 /*
267  * Populate the set of possible IRQs for each device.
268  */
269 static ACPI_STATUS
270 link_add_prs(ACPI_RESOURCE *res, void *context)
271 {
272 	ACPI_RESOURCE *tmp;
273 	struct link_res_request *req;
274 	struct link *link;
275 	UINT8 *irqs = NULL;
276 	UINT32 *ext_irqs = NULL;
277 	int i, is_ext_irq = 1;
278 
279 	ACPI_SERIAL_ASSERT(pci_link);
280 	req = (struct link_res_request *)context;
281 	switch (res->Type) {
282 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
283 		switch (req->in_dpf) {
284 		case DPF_OUTSIDE:
285 			/* We've started the first DPF. */
286 			req->in_dpf = DPF_FIRST;
287 			break;
288 		case DPF_FIRST:
289 			/* We've started the second DPF. */
290 			req->in_dpf = DPF_IGNORE;
291 			break;
292 		}
293 		break;
294 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
295 		/* We are finished with DPF parsing. */
296 		KASSERT(req->in_dpf != DPF_OUTSIDE,
297 		    ("%s: end dpf when not parsing a dpf", __func__));
298 		req->in_dpf = DPF_OUTSIDE;
299 		break;
300 	case ACPI_RESOURCE_TYPE_IRQ:
301 		is_ext_irq = 0;
302 		/* fall through */
303 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
304 		/*
305 		 * Don't parse resources if we are in a DPF set that we are
306 		 * ignoring.
307 		 */
308 		if (req->in_dpf == DPF_IGNORE)
309 			break;
310 
311 		KASSERT(req->link_index < req->sc->pl_num_links,
312 		    ("%s: array boundary violation", __func__));
313 		link = &req->sc->pl_links[req->link_index];
314 		if (link->l_res_index == -1) {
315 			KASSERT(req->sc->pl_crs_bad,
316 			    ("res_index should be set"));
317 			link->l_res_index = req->res_index;
318 		}
319 		req->link_index++;
320 		req->res_index++;
321 
322 		/*
323 		 * Stash a copy of the resource for later use when doing
324 		 * _SRS.
325 		 */
326 		tmp = &link->l_prs_template;
327 		if (is_ext_irq) {
328 			bcopy(res, tmp, ACPI_RS_SIZE(tmp->Data.ExtendedIrq));
329 
330 			/*
331 			 * XXX acpi_AppendBufferResource() cannot handle
332 			 * optional data.
333 			 */
334 			bzero(&tmp->Data.ExtendedIrq.ResourceSource,
335 			    sizeof(tmp->Data.ExtendedIrq.ResourceSource));
336 			tmp->Length = ACPI_RS_SIZE(tmp->Data.ExtendedIrq);
337 
338 			link->l_num_irqs =
339 			    res->Data.ExtendedIrq.InterruptCount;
340 			ext_irqs = res->Data.ExtendedIrq.Interrupts;
341 		} else {
342 			bcopy(res, tmp, ACPI_RS_SIZE(tmp->Data.Irq));
343 			link->l_num_irqs = res->Data.Irq.InterruptCount;
344 			irqs = res->Data.Irq.Interrupts;
345 		}
346 		if (link->l_num_irqs == 0)
347 			break;
348 
349 		/*
350 		 * Save a list of the valid IRQs.  Also, if all of the
351 		 * valid IRQs are ISA IRQs, then mark this link as
352 		 * routed via an ISA interrupt.
353 		 */
354 		link->l_isa_irq = TRUE;
355 
356 		link->l_irqs = kmalloc(sizeof(int) * link->l_num_irqs,
357 		    M_PCI_LINK, M_WAITOK | M_ZERO);
358 		for (i = 0; i < link->l_num_irqs; i++) {
359 			if (is_ext_irq) {
360 				link->l_irqs[i] = ext_irqs[i];
361 				if (ext_irqs[i] >= NUM_ISA_INTERRUPTS)
362 					link->l_isa_irq = FALSE;
363 			} else {
364 				link->l_irqs[i] = irqs[i];
365 				if (irqs[i] >= NUM_ISA_INTERRUPTS)
366 					link->l_isa_irq = FALSE;
367 			}
368 		}
369 
370 		/*
371 		 * If this is not an ISA IRQ but _CRS used a non-extended
372 		 * IRQ descriptor, don't use _CRS as a template for _SRS.
373 		 */
374 		if (!req->sc->pl_crs_bad && !link->l_isa_irq &&
375 		    link->l_crs_type == ACPI_RESOURCE_TYPE_IRQ)
376 			req->sc->pl_crs_bad = TRUE;
377 		break;
378 	default:
379 		if (req->in_dpf == DPF_IGNORE)
380 			break;
381 		if (req->sc->pl_crs_bad)
382 			device_printf(req->sc->pl_dev,
383 		    "Warning: possible resource %d will be lost during _SRS\n",
384 			    req->res_index);
385 		req->res_index++;
386 	}
387 	return (AE_OK);
388 }
389 
390 static int
391 link_valid_irq(struct link *link, int irq)
392 {
393 	int i;
394 
395 	ACPI_SERIAL_ASSERT(pci_link);
396 
397 	/* Invalid interrupts are never valid. */
398 	if (!PCI_INTERRUPT_VALID(irq))
399 		return (FALSE);
400 
401 	/* Any interrupt in the list of possible interrupts is valid. */
402 	for (i = 0; i < link->l_num_irqs; i++)
403 		if (link->l_irqs[i] == irq)
404 			 return (TRUE);
405 
406 	/*
407 	 * For links routed via an ISA interrupt, if the SCI is routed via
408 	 * an ISA interrupt, the SCI is always treated as a valid IRQ.
409 	 */
410 	if (link->l_isa_irq && AcpiGbl_FADT.SciInterrupt == irq &&
411 	    irq < NUM_ISA_INTERRUPTS)
412 		return (TRUE);
413 
414 	/* If the interrupt wasn't found in the list it is not valid. */
415 	return (FALSE);
416 }
417 
418 static void
419 acpi_pci_link_dump(struct acpi_pci_link_softc *sc, int header, const char *tag)
420 {
421 	struct link *link;
422 	char buf[16];
423 	int i, j;
424 
425 	ACPI_SERIAL_ASSERT(pci_link);
426 	if (header) {
427 		ksnprintf(buf, sizeof(buf), "%s:",
428 		    device_get_nameunit(sc->pl_dev));
429 		kprintf("%-16.16s  Index  IRQ  Rtd  Ref  IRQs\n", buf);
430 	}
431 	for (i = 0; i < sc->pl_num_links; i++) {
432 		link = &sc->pl_links[i];
433 		kprintf("  %-14.14s  %5d  %3d   %c   %3d ", i == 0 ? tag : "", i,
434 		    link->l_irq, link->l_routed ? 'Y' : 'N',
435 		    link->l_references);
436 		if (link->l_num_irqs == 0)
437 			kprintf(" none");
438 		else for (j = 0; j < link->l_num_irqs; j++)
439 			kprintf(" %d", link->l_irqs[j]);
440 		kprintf("\n");
441 	}
442 }
443 
444 static int
445 acpi_pci_link_attach(device_t dev)
446 {
447 	struct acpi_pci_link_softc *sc;
448 	struct link_count_request creq;
449 	struct link_res_request rreq;
450 	ACPI_STATUS status;
451 	int i;
452 
453 	sc = device_get_softc(dev);
454 	sc->pl_dev = dev;
455 	ACPI_SERIAL_INIT(pci_link);
456 	ACPI_SERIAL_BEGIN(pci_link);
457 
458 	/*
459 	 * Count the number of current resources so we know how big of
460 	 * a link array to allocate.  On some systems, _CRS is broken,
461 	 * so for those systems try to derive the count from _PRS instead.
462 	 */
463 	creq.in_dpf = DPF_OUTSIDE;
464 	creq.count = 0;
465 	status = AcpiWalkResources(acpi_get_handle(dev), "_CRS",
466 	    acpi_count_irq_resources, &creq);
467 	sc->pl_crs_bad = ACPI_FAILURE(status);
468 	if (sc->pl_crs_bad) {
469 		creq.in_dpf = DPF_OUTSIDE;
470 		creq.count = 0;
471 		status = AcpiWalkResources(acpi_get_handle(dev), "_PRS",
472 		    acpi_count_irq_resources, &creq);
473 		if (ACPI_FAILURE(status)) {
474 			device_printf(dev,
475 			    "Unable to parse _CRS or _PRS: %s\n",
476 			    AcpiFormatException(status));
477 			ACPI_SERIAL_END(pci_link);
478 			return (ENXIO);
479 		}
480 	}
481 	sc->pl_num_links = creq.count;
482 	if (creq.count == 0) {
483 		ACPI_SERIAL_END(pci_link);
484 		return (0);
485 	}
486 	sc->pl_links = kmalloc(sizeof(struct link) * sc->pl_num_links,
487 	    M_PCI_LINK, M_WAITOK | M_ZERO);
488 
489 	/* Initialize the child links. */
490 	for (i = 0; i < sc->pl_num_links; i++) {
491 		sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
492 		sc->pl_links[i].l_bios_irq = PCI_INVALID_IRQ;
493 		sc->pl_links[i].l_sc = sc;
494 		sc->pl_links[i].l_isa_irq = FALSE;
495 		sc->pl_links[i].l_res_index = -1;
496 	}
497 
498 	/* Try to read the current settings from _CRS if it is valid. */
499 	if (!sc->pl_crs_bad) {
500 		rreq.in_dpf = DPF_OUTSIDE;
501 		rreq.link_index = 0;
502 		rreq.res_index = 0;
503 		rreq.sc = sc;
504 		status = AcpiWalkResources(acpi_get_handle(dev), "_CRS",
505 		    link_add_crs, &rreq);
506 		if (ACPI_FAILURE(status)) {
507 			device_printf(dev, "Unable to parse _CRS: %s\n",
508 			    AcpiFormatException(status));
509 			goto fail;
510 		}
511 	}
512 
513 	/*
514 	 * Try to read the possible settings from _PRS.  Note that if the
515 	 * _CRS is toast, we depend on having a working _PRS.  However, if
516 	 * _CRS works, then it is ok for _PRS to be missing.
517 	 */
518 	rreq.in_dpf = DPF_OUTSIDE;
519 	rreq.link_index = 0;
520 	rreq.res_index = 0;
521 	rreq.sc = sc;
522 	status = AcpiWalkResources(acpi_get_handle(dev), "_PRS",
523 	    link_add_prs, &rreq);
524 	if (ACPI_FAILURE(status) &&
525 	    (status != AE_NOT_FOUND || sc->pl_crs_bad)) {
526 		device_printf(dev, "Unable to parse _PRS: %s\n",
527 		    AcpiFormatException(status));
528 		goto fail;
529 	}
530 	if (bootverbose)
531 		acpi_pci_link_dump(sc, 1, "Initial Probe");
532 
533 	/* Verify initial IRQs if we have _PRS. */
534 	if (status != AE_NOT_FOUND)
535 		for (i = 0; i < sc->pl_num_links; i++)
536 			if (!link_valid_irq(&sc->pl_links[i],
537 			    sc->pl_links[i].l_irq))
538 				sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
539 	if (bootverbose)
540 		acpi_pci_link_dump(sc, 0, "Validation");
541 
542 	/* Save initial IRQs. */
543 	for (i = 0; i < sc->pl_num_links; i++)
544 		sc->pl_links[i].l_initial_irq = sc->pl_links[i].l_irq;
545 
546 	/*
547 	 * Try to disable this link.  If successful, set the current IRQ to
548 	 * zero and flags to indicate this link is not routed.  If we can't
549 	 * run _DIS (i.e., the method doesn't exist), assume the initial
550 	 * IRQ was routed by the BIOS.
551 	 */
552 	if (ACPI_SUCCESS(AcpiEvaluateObject(acpi_get_handle(dev), "_DIS", NULL,
553 	    NULL)))
554 		for (i = 0; i < sc->pl_num_links; i++)
555 			sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
556 	else
557 		for (i = 0; i < sc->pl_num_links; i++)
558 			if (PCI_INTERRUPT_VALID(sc->pl_links[i].l_irq))
559 				sc->pl_links[i].l_routed = TRUE;
560 	if (bootverbose)
561 		acpi_pci_link_dump(sc, 0, "After Disable");
562 	ACPI_SERIAL_END(pci_link);
563 	return (0);
564 fail:
565 	ACPI_SERIAL_END(pci_link);
566 	for (i = 0; i < sc->pl_num_links; i++)
567 		if (sc->pl_links[i].l_irqs != NULL)
568 			kfree(sc->pl_links[i].l_irqs, M_PCI_LINK);
569 	kfree(sc->pl_links, M_PCI_LINK);
570 	return (ENXIO);
571 }
572 
573 /* XXX: Note that this is identical to pci_pir_search_irq(). */
574 static uint8_t
575 acpi_pci_link_search_irq(int bus, int device, int pin)
576 {
577 	uint32_t value;
578 	uint8_t func, maxfunc;
579 
580 	/* See if we have a valid device at function 0. */
581 	value = pci_cfgregread(bus, device, 0, PCIR_HDRTYPE, 1);
582 	if ((value & PCIM_HDRTYPE) > PCI_MAXHDRTYPE)
583 		return (PCI_INVALID_IRQ);
584 	if (value & PCIM_MFDEV)
585 		maxfunc = PCI_FUNCMAX;
586 	else
587 		maxfunc = 0;
588 
589 	/* Scan all possible functions at this device. */
590 	for (func = 0; func <= maxfunc; func++) {
591 		value = pci_cfgregread(bus, device, func, PCIR_DEVVENDOR, 4);
592 		if (value == 0xffffffff)
593 			continue;
594 		value = pci_cfgregread(bus, device, func, PCIR_INTPIN, 1);
595 
596 		/*
597 		 * See if it uses the pin in question.  Note that the passed
598 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
599 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
600 		 */
601 		if (value != pin + 1)
602 			continue;
603 		value = pci_cfgregread(bus, device, func, PCIR_INTLINE, 1);
604 		if (bootverbose)
605 			kprintf(
606 		"ACPI: Found matching pin for %d.%d.INT%c at func %d: %d\n",
607 			    bus, device, pin + 'A', func, value);
608 		if (value != PCI_INVALID_IRQ)
609 			return (value);
610 	}
611 	return (PCI_INVALID_IRQ);
612 }
613 
614 /*
615  * Find the link structure that corresponds to the resource index passed in
616  * via 'source_index'.
617  */
618 static struct link *
619 acpi_pci_link_lookup(device_t dev, int source_index)
620 {
621 	struct acpi_pci_link_softc *sc;
622 	int i;
623 
624 	ACPI_SERIAL_ASSERT(pci_link);
625 	sc = device_get_softc(dev);
626 	for (i = 0; i < sc->pl_num_links; i++)
627 		if (sc->pl_links[i].l_res_index == source_index)
628 			return (&sc->pl_links[i]);
629 	return (NULL);
630 }
631 
632 void
633 acpi_pci_link_add_reference(device_t dev, int index, device_t pcib, int slot,
634     int pin)
635 {
636 	struct link *link;
637 	uint8_t bios_irq;
638 	uintptr_t bus;
639 
640 	/*
641 	 * Look up the PCI bus for the specified PCI bridge device.  Note
642 	 * that the PCI bridge device might not have any children yet.
643 	 * However, looking up its bus number doesn't require a valid child
644 	 * device, so we just pass NULL.
645 	 */
646 	if (BUS_READ_IVAR(pcib, NULL, PCIB_IVAR_BUS, &bus) != 0) {
647 		device_printf(pcib, "Unable to read PCI bus number");
648 		panic("PCI bridge without a bus number");
649 	}
650 
651 	/* Bump the reference count. */
652 	ACPI_SERIAL_BEGIN(pci_link);
653 	link = acpi_pci_link_lookup(dev, index);
654 	if (link == NULL) {
655 		device_printf(dev, "apparently invalid index %d\n", index);
656 		ACPI_SERIAL_END(pci_link);
657 		return;
658 	}
659 	link->l_references++;
660 	if (link->l_routed)
661 		pci_link_interrupt_weights[link->l_irq]++;
662 
663 	/*
664 	 * The BIOS only routes interrupts via ISA IRQs using the ATPICs
665 	 * (8259As).  Thus, if this link is routed via an ISA IRQ, go
666 	 * look to see if the BIOS routed an IRQ for this link at the
667 	 * indicated (bus, slot, pin).  If so, we prefer that IRQ for
668 	 * this link and add that IRQ to our list of known-good IRQs.
669 	 * This provides a good work-around for link devices whose _CRS
670 	 * method is either broken or bogus.  We only use the value
671 	 * returned by _CRS if we can't find a valid IRQ via this method
672 	 * in fact.
673 	 *
674 	 * If this link is not routed via an ISA IRQ (because we are using
675 	 * APIC for example), then don't bother looking up the BIOS IRQ
676 	 * as if we find one it won't be valid anyway.
677 	 */
678 	if (!link->l_isa_irq) {
679 		ACPI_SERIAL_END(pci_link);
680 		return;
681 	}
682 
683 	/* Try to find a BIOS IRQ setting from any matching devices. */
684 	bios_irq = acpi_pci_link_search_irq(bus, slot, pin);
685 	if (!PCI_INTERRUPT_VALID(bios_irq)) {
686 		ACPI_SERIAL_END(pci_link);
687 		return;
688 	}
689 
690 	/* Validate the BIOS IRQ. */
691 	if (!link_valid_irq(link, bios_irq)) {
692 		device_printf(dev, "BIOS IRQ %u for %d.%d.INT%c is invalid\n",
693 		    bios_irq, (int)bus, slot, pin + 'A');
694 	} else if (!PCI_INTERRUPT_VALID(link->l_bios_irq)) {
695 		link->l_bios_irq = bios_irq;
696 		/*
697 		 * SCI setting is handled by acpi_pci_link_identify()
698 		 */
699 		if (bios_irq < NUM_ISA_INTERRUPTS &&
700 		    AcpiGbl_FADT.SciInterrupt != bios_irq)
701 			pci_link_bios_isa_irqs |= (1 << bios_irq);
702 		if (bios_irq != link->l_initial_irq &&
703 		    PCI_INTERRUPT_VALID(link->l_initial_irq))
704 			device_printf(dev,
705 			    "BIOS IRQ %u does not match initial IRQ %u\n",
706 			    bios_irq, link->l_initial_irq);
707 	} else if (bios_irq != link->l_bios_irq)
708 		device_printf(dev,
709 	    "BIOS IRQ %u for %d.%d.INT%c does not match previous BIOS IRQ %u\n",
710 		    bios_irq, (int)bus, slot, pin + 'A',
711 		    link->l_bios_irq);
712 	ACPI_SERIAL_END(pci_link);
713 }
714 
715 static ACPI_STATUS
716 acpi_pci_link_srs_from_crs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
717 {
718 	ACPI_RESOURCE *end, *res;
719 	ACPI_STATUS status;
720 	struct link *link;
721 	int i, in_dpf;
722 
723 	/* Fetch the _CRS. */
724 	ACPI_SERIAL_ASSERT(pci_link);
725 	srsbuf->Pointer = NULL;
726 	srsbuf->Length = ACPI_ALLOCATE_BUFFER;
727 	status = AcpiGetCurrentResources(acpi_get_handle(sc->pl_dev), srsbuf);
728 	if (ACPI_SUCCESS(status) && srsbuf->Pointer == NULL)
729 		status = AE_NO_MEMORY;
730 	if (ACPI_FAILURE(status)) {
731 		if (bootverbose)
732 			device_printf(sc->pl_dev,
733 			    "Unable to fetch current resources: %s\n",
734 			    AcpiFormatException(status));
735 		return (status);
736 	}
737 
738 	/* Fill in IRQ resources via link structures. */
739 	link = sc->pl_links;
740 	i = 0;
741 	in_dpf = DPF_OUTSIDE;
742 	res = (ACPI_RESOURCE *)srsbuf->Pointer;
743 	end = (ACPI_RESOURCE *)((char *)srsbuf->Pointer + srsbuf->Length);
744 	for (;;) {
745 		switch (res->Type) {
746 		case ACPI_RESOURCE_TYPE_START_DEPENDENT:
747 			switch (in_dpf) {
748 			case DPF_OUTSIDE:
749 				/* We've started the first DPF. */
750 				in_dpf = DPF_FIRST;
751 				break;
752 			case DPF_FIRST:
753 				/* We've started the second DPF. */
754 				panic(
755 		"%s: Multiple dependent functions within a current resource",
756 				    __func__);
757 				break;
758 			}
759 			break;
760 		case ACPI_RESOURCE_TYPE_END_DEPENDENT:
761 			/* We are finished with DPF parsing. */
762 			KASSERT(in_dpf != DPF_OUTSIDE,
763 			    ("%s: end dpf when not parsing a dpf", __func__));
764 			in_dpf = DPF_OUTSIDE;
765 			break;
766 		case ACPI_RESOURCE_TYPE_IRQ:
767 			KKASSERT(i < sc->pl_num_links);
768 			res->Data.Irq.InterruptCount = 1;
769 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
770 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS,
771 		("%s: can't put non-ISA IRQ %d in legacy IRQ resource type",
772 				    __func__, link->l_irq));
773 				res->Data.Irq.Interrupts[0] = link->l_irq;
774 			} else
775 				res->Data.Irq.Interrupts[0] = 0;
776 			link++;
777 			i++;
778 			break;
779 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
780 			KKASSERT(i < sc->pl_num_links);
781 			res->Data.ExtendedIrq.InterruptCount = 1;
782 			if (PCI_INTERRUPT_VALID(link->l_irq))
783 				res->Data.ExtendedIrq.Interrupts[0] =
784 				    link->l_irq;
785 			else
786 				res->Data.ExtendedIrq.Interrupts[0] = 0;
787 			link++;
788 			i++;
789 			break;
790 		}
791 		if (res->Type == ACPI_RESOURCE_TYPE_END_TAG)
792 			break;
793 		res = ACPI_NEXT_RESOURCE(res);
794 		if (res >= end)
795 			break;
796 	}
797 	return (AE_OK);
798 }
799 
800 static ACPI_STATUS
801 acpi_pci_link_srs_from_links(struct acpi_pci_link_softc *sc,
802     ACPI_BUFFER *srsbuf)
803 {
804 	ACPI_RESOURCE newres;
805 	ACPI_STATUS status;
806 	struct link *link;
807 	int i;
808 
809 	/* Start off with an empty buffer. */
810 	srsbuf->Pointer = NULL;
811 	link = sc->pl_links;
812 	for (i = 0; i < sc->pl_num_links; i++) {
813 
814 		/* Add a new IRQ resource from each link. */
815 		link = &sc->pl_links[i];
816 		if (link->l_prs_template.Type == ACPI_RESOURCE_TYPE_IRQ) {
817 
818 			/* Build an IRQ resource. */
819 			bcopy(&link->l_prs_template, &newres,
820 			    ACPI_RS_SIZE(newres.Data.Irq));
821 			newres.Data.Irq.InterruptCount = 1;
822 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
823 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS,
824 		("%s: can't put non-ISA IRQ %d in legacy IRQ resource type",
825 				    __func__, link->l_irq));
826 				newres.Data.Irq.Interrupts[0] = link->l_irq;
827 			} else
828 				newres.Data.Irq.Interrupts[0] = 0;
829 		} else {
830 
831 			/* Build an ExtIRQ resuorce. */
832 			bcopy(&link->l_prs_template, &newres,
833 			    ACPI_RS_SIZE(newres.Data.ExtendedIrq));
834 			newres.Data.ExtendedIrq.InterruptCount = 1;
835 			if (PCI_INTERRUPT_VALID(link->l_irq))
836 				newres.Data.ExtendedIrq.Interrupts[0] =
837 				    link->l_irq;
838 			else
839 				newres.Data.ExtendedIrq.Interrupts[0] = 0;
840 		}
841 
842 		/* Add the new resource to the end of the _SRS buffer. */
843 		status = acpi_AppendBufferResource(srsbuf, &newres);
844 		if (ACPI_FAILURE(status)) {
845 			device_printf(sc->pl_dev,
846 			    "Unable to build resources: %s\n",
847 			    AcpiFormatException(status));
848 			if (srsbuf->Pointer != NULL)
849 				AcpiOsFree(srsbuf->Pointer);
850 			return (status);
851 		}
852 	}
853 	return (AE_OK);
854 }
855 
856 static ACPI_STATUS
857 acpi_pci_link_route_irqs(device_t dev)
858 {
859 	struct acpi_pci_link_softc *sc;
860 	ACPI_RESOURCE *resource, *end;
861 	ACPI_BUFFER srsbuf;
862 	ACPI_STATUS status;
863 	struct link *link;
864 	int i;
865 
866 	ACPI_SERIAL_ASSERT(pci_link);
867 	sc = device_get_softc(dev);
868 	if (sc->pl_crs_bad)
869 		status = acpi_pci_link_srs_from_links(sc, &srsbuf);
870 	else
871 		status = acpi_pci_link_srs_from_crs(sc, &srsbuf);
872 
873 	/* Write out new resources via _SRS. */
874 	status = AcpiSetCurrentResources(acpi_get_handle(dev), &srsbuf);
875 	if (ACPI_FAILURE(status)) {
876 		device_printf(dev, "Unable to route IRQs: %s\n",
877 		    AcpiFormatException(status));
878 		AcpiOsFree(srsbuf.Pointer);
879 		return (status);
880 	}
881 
882 	/*
883 	 * Perform acpi_config_intr() on each IRQ resource if it was just
884 	 * routed for the first time.
885 	 */
886 	link = sc->pl_links;
887 	i = 0;
888 	resource = (ACPI_RESOURCE *)srsbuf.Pointer;
889 	end = (ACPI_RESOURCE *)((char *)srsbuf.Pointer + srsbuf.Length);
890 	for (;;) {
891 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
892 			break;
893 		switch (resource->Type) {
894 		case ACPI_RESOURCE_TYPE_IRQ:
895 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
896 			KKASSERT(i < sc->pl_num_links);
897 
898 			/*
899 			 * Only configure the interrupt and update the
900 			 * weights if this link has a valid IRQ and was
901 			 * previously unrouted.
902 			 */
903 			if (!link->l_routed &&
904 			    PCI_INTERRUPT_VALID(link->l_irq)) {
905 				link->l_routed = TRUE;
906 				acpi_config_intr(dev, resource);
907 				pci_link_interrupt_weights[link->l_irq] +=
908 				    link->l_references;
909 			}
910 			link++;
911 			i++;
912 			break;
913 		}
914 		resource = ACPI_NEXT_RESOURCE(resource);
915 		if (resource >= end)
916 			break;
917 	}
918 	AcpiOsFree(srsbuf.Pointer);
919 	return (AE_OK);
920 }
921 
922 static int
923 acpi_pci_link_resume(device_t dev)
924 {
925 	struct acpi_pci_link_softc *sc;
926 	ACPI_STATUS status;
927 	int i, routed;
928 
929 	/*
930 	 * If all of our links are routed, then restore the link via _SRS,
931 	 * otherwise, disable the link via _DIS.
932 	 */
933 	ACPI_SERIAL_BEGIN(pci_link);
934 	sc = device_get_softc(dev);
935 	routed = 0;
936 	for (i = 0; i < sc->pl_num_links; i++)
937 		if (sc->pl_links[i].l_routed)
938 			routed++;
939 	if (routed == sc->pl_num_links)
940 		status = acpi_pci_link_route_irqs(dev);
941 	else {
942 		AcpiEvaluateObject(acpi_get_handle(dev), "_DIS", NULL, NULL);
943 		status = AE_OK;
944 	}
945 	ACPI_SERIAL_END(pci_link);
946 	if (ACPI_FAILURE(status))
947 		return (ENXIO);
948 	else
949 		return (0);
950 }
951 
952 /*
953  * Pick an IRQ to use for this unrouted link.
954  */
955 static uint8_t
956 acpi_pci_link_choose_irq(device_t dev, struct link *link)
957 {
958 	char tunable_buffer[64], link_name[5];
959 	uint8_t best_irq, pos_irq;
960 	int best_weight, pos_weight, i;
961 
962 	KASSERT(!link->l_routed, ("%s: link already routed", __func__));
963 	KASSERT(!PCI_INTERRUPT_VALID(link->l_irq),
964 	    ("%s: link already has an IRQ", __func__));
965 
966 	/* Check for a tunable override. */
967 	if (ACPI_SUCCESS(acpi_short_name(acpi_get_handle(dev), link_name,
968 	    sizeof(link_name)))) {
969 		ksnprintf(tunable_buffer, sizeof(tunable_buffer),
970 		    "hw.pci.link.%s.%d.irq", link_name, link->l_res_index);
971 		if (kgetenv_int(tunable_buffer, &i) && PCI_INTERRUPT_VALID(i)) {
972 			if (!link_valid_irq(link, i))
973 				device_printf(dev,
974 				    "Warning, IRQ %d is not listed as valid\n",
975 				    i);
976 			return (i);
977 		}
978 		ksnprintf(tunable_buffer, sizeof(tunable_buffer),
979 		    "hw.pci.link.%s.irq", link_name);
980 		if (kgetenv_int(tunable_buffer, &i) && PCI_INTERRUPT_VALID(i)) {
981 			if (!link_valid_irq(link, i))
982 				device_printf(dev,
983 				    "Warning, IRQ %d is not listed as valid\n",
984 				    i);
985 			return (i);
986 		}
987 	}
988 
989 	/*
990 	 * If we have a valid BIOS IRQ, use that.  We trust what the BIOS
991 	 * says it routed over what _CRS says the link thinks is routed.
992 	 */
993 	if (PCI_INTERRUPT_VALID(link->l_bios_irq))
994 		return (link->l_bios_irq);
995 
996 	/*
997 	 * If we don't have a BIOS IRQ but do have a valid IRQ from _CRS,
998 	 * then use that.
999 	 */
1000 	if (PCI_INTERRUPT_VALID(link->l_initial_irq))
1001 		return (link->l_initial_irq);
1002 
1003 	/*
1004 	 * Ok, we have no useful hints, so we have to pick from the
1005 	 * possible IRQs.  For ISA IRQs we only use interrupts that
1006 	 * have already been used by the BIOS.
1007 	 */
1008 	best_irq = PCI_INVALID_IRQ;
1009 	best_weight = INT_MAX;
1010 	for (i = 0; i < link->l_num_irqs; i++) {
1011 		pos_irq = link->l_irqs[i];
1012 		if (pos_irq < NUM_ISA_INTERRUPTS &&
1013 		    (pci_link_bios_isa_irqs & 1 << pos_irq) == 0)
1014 			continue;
1015 		pos_weight = pci_link_interrupt_weights[pos_irq];
1016 		if (pos_weight < best_weight) {
1017 			best_weight = pos_weight;
1018 			best_irq = pos_irq;
1019 		}
1020 	}
1021 
1022         /*
1023 	 * If this is an ISA IRQ and SCI could be shared, try using
1024 	 * the SCI as a fallback.
1025 	 */
1026 	if (link->l_isa_irq && acpi_sci_pci_shareable()) {
1027 		pos_irq = AcpiGbl_FADT.SciInterrupt;
1028 		pos_weight = pci_link_interrupt_weights[pos_irq];
1029 		if (pos_weight < best_weight) {
1030 			best_weight = pos_weight;
1031 			best_irq = pos_irq;
1032 		}
1033 	}
1034 
1035 	if (PCI_INTERRUPT_VALID(best_irq)) {
1036 		if (bootverbose)
1037 			device_printf(dev, "Picked IRQ %u with weight %d\n",
1038 			    best_irq, best_weight);
1039 	} else
1040 		device_printf(dev, "Unable to choose an IRQ\n");
1041 	return (best_irq);
1042 }
1043 
1044 int
1045 acpi_pci_link_route_interrupt(device_t dev, int index)
1046 {
1047 	struct link *link;
1048 
1049 	if (acpi_disabled("pci_link"))
1050 		return (PCI_INVALID_IRQ);
1051 
1052 	ACPI_SERIAL_BEGIN(pci_link);
1053 	link = acpi_pci_link_lookup(dev, index);
1054 	if (link == NULL)
1055 		panic("%s: apparently invalid index %d", __func__, index);
1056 
1057 	/*
1058 	 * If this link device is already routed to an interrupt, just return
1059 	 * the interrupt it is routed to.
1060 	 */
1061 	if (link->l_routed) {
1062 		KASSERT(PCI_INTERRUPT_VALID(link->l_irq),
1063 		    ("%s: link is routed but has an invalid IRQ", __func__));
1064 		ACPI_SERIAL_END(pci_link);
1065 		return (link->l_irq);
1066 	}
1067 
1068 	/* Choose an IRQ if we need one. */
1069 	if (!PCI_INTERRUPT_VALID(link->l_irq)) {
1070 		link->l_irq = acpi_pci_link_choose_irq(dev, link);
1071 
1072 		/*
1073 		 * Try to route the interrupt we picked.  If it fails, then
1074 		 * assume the interrupt is not routed.
1075 		 */
1076 		if (PCI_INTERRUPT_VALID(link->l_irq)) {
1077 			acpi_pci_link_route_irqs(dev);
1078 			if (!link->l_routed)
1079 				link->l_irq = PCI_INVALID_IRQ;
1080 		}
1081 	}
1082 	ACPI_SERIAL_END(pci_link);
1083 	return (link->l_irq);
1084 }
1085 
1086 /*
1087  * This is gross, but we abuse the identify routine to perform one-time
1088  * SYSINIT() style initialization for the driver.
1089  */
1090 static void
1091 acpi_pci_link_identify(driver_t *driver, device_t parent)
1092 {
1093 	/*
1094 	 * If the SCI is an ISA IRQ and could be shared,
1095 	 * add it to the bitmask of known good ISA IRQs.
1096 	 */
1097 	if (AcpiGbl_FADT.SciInterrupt < NUM_ISA_INTERRUPTS &&
1098 	    acpi_sci_pci_shareable())
1099 		pci_link_bios_isa_irqs |= (1 << AcpiGbl_FADT.SciInterrupt);
1100 }
1101 
1102 static device_method_t acpi_pci_link_methods[] = {
1103 	/* Device interface */
1104 	DEVMETHOD(device_identify,	acpi_pci_link_identify),
1105 	DEVMETHOD(device_probe,		acpi_pci_link_probe),
1106 	DEVMETHOD(device_attach,	acpi_pci_link_attach),
1107 	DEVMETHOD(device_resume,	acpi_pci_link_resume),
1108 
1109 	DEVMETHOD_END
1110 };
1111 
1112 static driver_t acpi_pci_link_driver = {
1113 	"pci_link",
1114 	acpi_pci_link_methods,
1115 	sizeof(struct acpi_pci_link_softc),
1116 	.gpri = KOBJ_GPRI_ACPI
1117 };
1118 
1119 static devclass_t pci_link_devclass;
1120 
1121 DRIVER_MODULE(acpi_pci_link, acpi, acpi_pci_link_driver, pci_link_devclass,
1122     NULL, NULL);
1123 MODULE_DEPEND(acpi_pci_link, acpi, 1, 1, 1);
1124