xref: /netbsd-src/sys/dev/acpi/acpi_pci_link.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /*	$NetBSD: acpi_pci_link.c,v 1.10 2007/12/09 20:27:53 jmcneill Exp $	*/
2 
3 /*-
4  * Copyright (c) 2002 Mitsuru IWASAKI <iwasaki@jp.freebsd.org>
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, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: acpi_pci_link.c,v 1.10 2007/12/09 20:27:53 jmcneill Exp $");
31 
32 #include "opt_acpi.h"
33 #include <sys/param.h>
34 #include <sys/kernel.h>
35 #include <sys/malloc.h>
36 #include <sys/queue.h>
37 #include <sys/reboot.h>
38 
39 #include <dev/acpi/acpica.h>
40 #include <dev/acpi/acpireg.h>
41 #include <dev/acpi/acpivar.h>
42 
43 #include <dev/pci/pcireg.h>
44 #include <dev/pci/pcivar.h>
45 
46 #define NUM_ISA_INTERRUPTS	16
47 #define NUM_ACPI_INTERRUPTS	256
48 
49 #define PCI_INVALID_IRQ	255
50 #define PCI_INTERRUPT_VALID(x) ((x) != PCI_INVALID_IRQ && (x) != 0)
51 
52 #define ACPI_SERIAL_BEGIN(x)
53 #define ACPI_SERIAL_END(x)
54 
55 /*
56  * An ACPI PCI link device may contain multiple links.  Each link has its
57  * own ACPI resource.  _PRT entries specify which link is being used via
58  * the Source Index.
59  *
60  * XXX: A note about Source Indices and DPFs:  Currently we assume that
61  * the DPF start and end tags are not counted towards the index that
62  * Source Index corresponds to.  Also, we assume that when DPFs are in use
63  * they various sets overlap in terms of Indices.  Here's an example
64  * resource list indicating these assumptions:
65  *
66  * Resource		Index
67  * --------		-----
68  * I/O Port		0
69  * Start DPF		-
70  * IRQ			1
71  * MemIO		2
72  * Start DPF		-
73  * IRQ			1
74  * MemIO		2
75  * End DPF		-
76  * DMA Channel		3
77  *
78  * The XXX is because I'm not sure if this is a valid assumption to make.
79  */
80 
81 /* States during DPF processing. */
82 #define	DPF_OUTSIDE	0
83 #define	DPF_FIRST	1
84 #define	DPF_IGNORE	2
85 
86 struct link;
87 
88 struct acpi_pci_link_softc {
89 	int	pl_num_links;
90 	int	pl_crs_bad;
91 	struct link *pl_links;
92 	char pl_name[32];
93 	ACPI_HANDLE pl_handle;
94 	void *pl_powerhook;
95 	TAILQ_ENTRY(acpi_pci_link_softc) pl_list;
96 };
97 
98 static TAILQ_HEAD(, acpi_pci_link_softc) acpi_pci_linkdevs =
99     TAILQ_HEAD_INITIALIZER(acpi_pci_linkdevs);
100 
101 
102 struct link {
103 	struct acpi_pci_link_softc *l_sc;
104 	uint8_t	l_bios_irq;
105 	uint8_t	l_irq;
106 	uint8_t l_trig;
107 	uint8_t l_pol;
108 	uint8_t	l_initial_irq;
109 	int	l_res_index;
110 	int	l_num_irqs;
111 	int	*l_irqs;
112 	int	l_references;
113 	int	l_dev_count;
114 	pcitag_t *l_devices;
115 	int	l_routed:1;
116 	int	l_isa_irq:1;
117 	ACPI_RESOURCE l_prs_template;
118 };
119 
120 struct link_count_request {
121 	int	in_dpf;
122 	int	count;
123 };
124 
125 struct link_res_request {
126 	struct acpi_pci_link_softc *sc;
127 	int	in_dpf;
128 	int	res_index;
129 	int	link_index;
130 };
131 
132 MALLOC_DEFINE(M_PCI_LINK, "pci_link", "ACPI PCI Link structures");
133 
134 static int pci_link_interrupt_weights[NUM_ACPI_INTERRUPTS];
135 static int pci_link_bios_isa_irqs;
136 
137 static ACPI_STATUS acpi_count_irq_resources(ACPI_RESOURCE *, void *);
138 static ACPI_STATUS link_add_crs(ACPI_RESOURCE *, void *);
139 static ACPI_STATUS link_add_prs(ACPI_RESOURCE *, void *);
140 static int link_valid_irq(struct link *, int);
141 static void acpi_pci_link_dump(struct acpi_pci_link_softc *);
142 static int acpi_pci_link_attach(struct acpi_pci_link_softc *);
143 static uint8_t acpi_pci_link_search_irq(struct acpi_pci_link_softc *, int, int,
144 					int);
145 static void acpi_pci_link_resume(int, void *);
146 static struct link *acpi_pci_link_lookup(struct acpi_pci_link_softc *, int);
147 static ACPI_STATUS acpi_pci_link_srs(struct acpi_pci_link_softc *,
148 				     ACPI_BUFFER *);
149 static ACPI_STATUS acpi_AppendBufferResource(ACPI_BUFFER *, ACPI_RESOURCE *);
150 
151 static ACPI_STATUS
152 acpi_count_irq_resources(ACPI_RESOURCE *res, void *context)
153 {
154 	struct link_count_request *req;
155 
156 	req = (struct link_count_request *)context;
157 	switch (res->Type) {
158 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
159 		switch (req->in_dpf) {
160 		case DPF_OUTSIDE:
161 			/* We've started the first DPF. */
162 			req->in_dpf = DPF_FIRST;
163 			break;
164 		case DPF_FIRST:
165 			/* We've started the second DPF. */
166 			req->in_dpf = DPF_IGNORE;
167 			break;
168 		}
169 		break;
170 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
171 		/* We are finished with DPF parsing. */
172 		KASSERT(req->in_dpf != DPF_OUTSIDE);
173 		req->in_dpf = DPF_OUTSIDE;
174 		break;
175 	case ACPI_RESOURCE_TYPE_IRQ:
176 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
177 		/*
178 		 * Don't count resources if we are in a DPF set that we are
179 		 * ignoring.
180 		 */
181 		if (req->in_dpf != DPF_IGNORE)
182 			req->count++;
183 	}
184 	return (AE_OK);
185 }
186 
187 static ACPI_STATUS
188 link_add_crs(ACPI_RESOURCE *res, void *context)
189 {
190 	struct link_res_request *req;
191 	struct link *link;
192 
193 	req = (struct link_res_request *)context;
194 	switch (res->Type) {
195 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
196 		switch (req->in_dpf) {
197 		case DPF_OUTSIDE:
198 			/* We've started the first DPF. */
199 			req->in_dpf = DPF_FIRST;
200 			break;
201 		case DPF_FIRST:
202 			/* We've started the second DPF. */
203 			panic(
204 		"%s: Multiple dependent functions within a current resource",
205 			    __func__);
206 			break;
207 		}
208 		break;
209 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
210 		/* We are finished with DPF parsing. */
211 		KASSERT(req->in_dpf != DPF_OUTSIDE);
212 		req->in_dpf = DPF_OUTSIDE;
213 		break;
214 	case ACPI_RESOURCE_TYPE_IRQ:
215 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
216 		KASSERT(req->link_index < req->sc->pl_num_links);
217 		link = &req->sc->pl_links[req->link_index];
218 		link->l_res_index = req->res_index;
219 		req->link_index++;
220 		req->res_index++;
221 
222 		/*
223 		 * Only use the current value if there's one IRQ.  Some
224 		 * systems return multiple IRQs (which is nonsense for _CRS)
225 		 * when the link hasn't been programmed.
226 		 */
227 		if (res->Type == ACPI_RESOURCE_TYPE_IRQ) {
228 			if (res->Data.Irq.InterruptCount == 1) {
229 				link->l_irq = res->Data.Irq.Interrupts[0];
230 				link->l_trig = res->Data.Irq.Triggering;
231 				link->l_pol = res->Data.Irq.Polarity;
232 		}
233 		} else if (res->Data.ExtendedIrq.InterruptCount == 1) {
234 			link->l_irq = res->Data.ExtendedIrq.Interrupts[0];
235 			link->l_trig = res->Data.ExtendedIrq.Triggering;
236 			link->l_pol = res->Data.ExtendedIrq.Polarity;
237 		}
238 
239 		/*
240 		 * An IRQ of zero means that the link isn't routed.
241 		 */
242 		if (link->l_irq == 0)
243 			link->l_irq = PCI_INVALID_IRQ;
244 		break;
245 	default:
246 		req->res_index++;
247 	}
248 	return (AE_OK);
249 }
250 
251 /*
252  * Populate the set of possible IRQs for each device.
253  */
254 static ACPI_STATUS
255 link_add_prs(ACPI_RESOURCE *res, void *context)
256 {
257 	struct link_res_request *req;
258 	struct link *link;
259 	UINT8 *irqs = NULL;
260 	UINT32 *ext_irqs = NULL;
261 	int i, is_ext_irq = 1;
262 
263 	req = (struct link_res_request *)context;
264 	switch (res->Type) {
265 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
266 		switch (req->in_dpf) {
267 		case DPF_OUTSIDE:
268 			/* We've started the first DPF. */
269 			req->in_dpf = DPF_FIRST;
270 			break;
271 		case DPF_FIRST:
272 			/* We've started the second DPF. */
273 			req->in_dpf = DPF_IGNORE;
274 			break;
275 		}
276 		break;
277 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
278 		/* We are finished with DPF parsing. */
279 		KASSERT(req->in_dpf != DPF_OUTSIDE);
280 		req->in_dpf = DPF_OUTSIDE;
281 		break;
282 	case ACPI_RESOURCE_TYPE_IRQ:
283 		is_ext_irq = 0;
284 		/* fall through */
285 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
286 		/*
287 		 * Don't parse resources if we are in a DPF set that we are
288 		 * ignoring.
289 		 */
290 		if (req->in_dpf == DPF_IGNORE)
291 			break;
292 
293 		KASSERT(req->link_index < req->sc->pl_num_links);
294 		link = &req->sc->pl_links[req->link_index];
295 		if (link->l_res_index == -1) {
296 			KASSERT(req->sc->pl_crs_bad);
297 			link->l_res_index = req->res_index;
298 		}
299 		req->link_index++;
300 		req->res_index++;
301 
302 		/*
303 		 * Stash a copy of the resource for later use when
304 		 * doing _SRS.
305 		 *
306 		 * Note that in theory res->Length may exceed the size
307 		 * of ACPI_RESOURCE, due to variable length lists in
308 		 * subtypes.  However, all uses of l_prs_template only
309 		 * rely on lists lengths of zero or one, for which
310 		 * sizeof(ACPI_RESOURCE) is sufficient space anyway.
311 		 * We cannot read longer than Length bytes, in case we
312 		 * read off the end of mapped memory.  So we read
313 		 * whichever length is shortest, Length or
314 		 * sizeof(ACPI_RESOURCE).
315 		 */
316 		KASSERT(res->Length >= ACPI_RS_SIZE_MIN);
317 
318 		memset(&link->l_prs_template, 0, sizeof(link->l_prs_template));
319 		memcpy(&link->l_prs_template, res,
320 		       MIN(res->Length, sizeof(link->l_prs_template)));
321 
322 		if (is_ext_irq) {
323 			link->l_num_irqs =
324 			    res->Data.ExtendedIrq.InterruptCount;
325 			link->l_trig = res->Data.ExtendedIrq.Triggering;
326 			link->l_pol = res->Data.ExtendedIrq.Polarity;
327 			ext_irqs = res->Data.ExtendedIrq.Interrupts;
328 		} else {
329 			link->l_num_irqs = res->Data.Irq.InterruptCount;
330 			link->l_trig = res->Data.Irq.Triggering;
331 			link->l_pol = res->Data.Irq.Polarity;
332 			irqs = res->Data.Irq.Interrupts;
333 		}
334 		if (link->l_num_irqs == 0)
335 			break;
336 
337 		/*
338 		 * Save a list of the valid IRQs.  Also, if all of the
339 		 * valid IRQs are ISA IRQs, then mark this link as
340 		 * routed via an ISA interrupt.
341 		 */
342 		link->l_isa_irq = TRUE;
343 		link->l_irqs = malloc(sizeof(int) * link->l_num_irqs,
344 		    M_PCI_LINK, M_WAITOK | M_ZERO);
345 		for (i = 0; i < link->l_num_irqs; i++) {
346 			if (is_ext_irq) {
347 				link->l_irqs[i] = ext_irqs[i];
348 				if (ext_irqs[i] >= NUM_ISA_INTERRUPTS)
349 					link->l_isa_irq = FALSE;
350 			} else {
351 				link->l_irqs[i] = irqs[i];
352 				if (irqs[i] >= NUM_ISA_INTERRUPTS)
353 					link->l_isa_irq = FALSE;
354 			}
355 		}
356 		break;
357 	default:
358 		if (req->in_dpf == DPF_IGNORE)
359 			break;
360 		if (req->sc->pl_crs_bad)
361 			aprint_normal("%s: Warning: possible resource %d "
362 			       "will be lost during _SRS\n", req->sc->pl_name,
363 			       req->res_index);
364 		req->res_index++;
365 	}
366 	return (AE_OK);
367 }
368 
369 static int
370 link_valid_irq(struct link *link, int irq)
371 {
372 	int i;
373 
374 	/* Invalid interrupts are never valid. */
375 	if (!PCI_INTERRUPT_VALID(irq))
376 		return (FALSE);
377 
378 	/* Any interrupt in the list of possible interrupts is valid. */
379 	for (i = 0; i < link->l_num_irqs; i++)
380 		if (link->l_irqs[i] == irq)
381 			 return (TRUE);
382 
383 	/*
384 	 * For links routed via an ISA interrupt, if the SCI is routed via
385 	 * an ISA interrupt, the SCI is always treated as a valid IRQ.
386 	 */
387 	if (link->l_isa_irq && AcpiGbl_FADT.SciInterrupt == irq &&
388 	    irq < NUM_ISA_INTERRUPTS)
389 		return (TRUE);
390 
391 	/* If the interrupt wasn't found in the list it is not valid. */
392 	return (FALSE);
393 }
394 
395 void
396 acpi_pci_link_state(void)
397 {
398 	struct acpi_pci_link_softc *sc;
399 
400 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
401 		acpi_pci_link_dump(sc);
402 	}
403 }
404 
405 static void
406 acpi_pci_link_dump(struct acpi_pci_link_softc *sc)
407 {
408 	struct link *link;
409 	int i, j;
410 
411 	printf("Link Device %s:\n", sc->pl_name);
412 	printf("Index  IRQ  Rtd  Ref  IRQs\n");
413 	for (i = 0; i < sc->pl_num_links; i++) {
414 		link = &sc->pl_links[i];
415 		printf("%5d  %3d   %c   %3d ", i, link->l_irq,
416 		    link->l_routed ? 'Y' : 'N',  link->l_references);
417 		if (link->l_num_irqs == 0)
418 			printf(" none");
419 		else for (j = 0; j < link->l_num_irqs; j++)
420 			printf(" %d", link->l_irqs[j]);
421 		printf(" polarity %u trigger %u\n", link->l_pol, link->l_trig);
422 	}
423 	printf("\n");
424 }
425 
426 static int
427 acpi_pci_link_attach(struct acpi_pci_link_softc *sc)
428 {
429 	struct link_count_request creq;
430 	struct link_res_request rreq;
431 	ACPI_STATUS status;
432 	int i;
433 
434 	ACPI_SERIAL_BEGIN(pci_link);
435 
436 	/*
437 	 * Count the number of current resources so we know how big of
438 	 * a link array to allocate.  On some systems, _CRS is broken,
439 	 * so for those systems try to derive the count from _PRS instead.
440 	 */
441 	creq.in_dpf = DPF_OUTSIDE;
442 	creq.count = 0;
443 	status = AcpiWalkResources(sc->pl_handle, "_CRS",
444 	    acpi_count_irq_resources, &creq);
445 	sc->pl_crs_bad = ACPI_FAILURE(status);
446 	if (sc->pl_crs_bad) {
447 		creq.in_dpf = DPF_OUTSIDE;
448 		creq.count = 0;
449 		status = AcpiWalkResources(sc->pl_handle, "_PRS",
450 		    acpi_count_irq_resources, &creq);
451 		if (ACPI_FAILURE(status)) {
452 			aprint_error("%s: Unable to parse _CRS or _PRS: %s\n",
453 			    sc->pl_name, AcpiFormatException(status));
454 			ACPI_SERIAL_END(pci_link);
455 			return (ENXIO);
456 		}
457 	}
458 	sc->pl_num_links = creq.count;
459 	if (creq.count == 0) {
460 		ACPI_SERIAL_END(pci_link);
461 		return (0);
462 	}
463 	sc->pl_links = malloc(sizeof(struct link) * sc->pl_num_links,
464 	    M_PCI_LINK, M_WAITOK | M_ZERO);
465 
466 	/* Initialize the child links. */
467 	for (i = 0; i < sc->pl_num_links; i++) {
468 		sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
469 		sc->pl_links[i].l_bios_irq = PCI_INVALID_IRQ;
470 		sc->pl_links[i].l_sc = sc;
471 		sc->pl_links[i].l_isa_irq = FALSE;
472 		sc->pl_links[i].l_res_index = -1;
473 		sc->pl_links[i].l_dev_count = 0;
474 		sc->pl_links[i].l_devices = NULL;
475 	}
476 
477 	/* Try to read the current settings from _CRS if it is valid. */
478 	if (!sc->pl_crs_bad) {
479 		rreq.in_dpf = DPF_OUTSIDE;
480 		rreq.link_index = 0;
481 		rreq.res_index = 0;
482 		rreq.sc = sc;
483 		status = AcpiWalkResources(sc->pl_handle, "_CRS",
484 		    link_add_crs, &rreq);
485 		if (ACPI_FAILURE(status)) {
486 			aprint_error("%s: Unable to parse _CRS: %s\n",
487 			    sc->pl_name, AcpiFormatException(status));
488 			goto fail;
489 		}
490 	}
491 
492 	/*
493 	 * Try to read the possible settings from _PRS.  Note that if the
494 	 * _CRS is toast, we depend on having a working _PRS.  However, if
495 	 * _CRS works, then it is ok for _PRS to be missing.
496 	 */
497 	rreq.in_dpf = DPF_OUTSIDE;
498 	rreq.link_index = 0;
499 	rreq.res_index = 0;
500 	rreq.sc = sc;
501 	status = AcpiWalkResources(sc->pl_handle, "_PRS",
502 	    link_add_prs, &rreq);
503 	if (ACPI_FAILURE(status) &&
504 	    (status != AE_NOT_FOUND || sc->pl_crs_bad)) {
505 		aprint_error("%s: Unable to parse _PRS: %s\n",
506 		    sc->pl_name, AcpiFormatException(status));
507 		goto fail;
508 	}
509 	if (boothowto & AB_VERBOSE) {
510 		aprint_normal("%s: Links after initial probe:\n", sc->pl_name);
511 		acpi_pci_link_dump(sc);
512 	}
513 
514 	/* Verify initial IRQs if we have _PRS. */
515 	if (status != AE_NOT_FOUND)
516 		for (i = 0; i < sc->pl_num_links; i++)
517 			if (!link_valid_irq(&sc->pl_links[i],
518 			    sc->pl_links[i].l_irq))
519 				sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
520 	if (boothowto & AB_VERBOSE) {
521 		printf("%s: Links after initial validation:\n", sc->pl_name);
522 		acpi_pci_link_dump(sc);
523 	}
524 
525 	/* Save initial IRQs. */
526 	for (i = 0; i < sc->pl_num_links; i++)
527 		sc->pl_links[i].l_initial_irq = sc->pl_links[i].l_irq;
528 
529 	/*
530 	 * Try to disable this link.  If successful, set the current IRQ to
531 	 * zero and flags to indicate this link is not routed.  If we can't
532 	 * run _DIS (i.e., the method doesn't exist), assume the initial
533 	 * IRQ was routed by the BIOS.
534 	 */
535 #if 0	/* XXX causes spontaneaous resets on some systems. Disabled for now. */
536 	if (ACPI_SUCCESS(AcpiEvaluateObject(sc->pl_handle, "_DIS", NULL,
537 	    NULL)))
538 		for (i = 0; i < sc->pl_num_links; i++)
539 			sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
540 	else
541 #endif
542 		for (i = 0; i < sc->pl_num_links; i++)
543 			if (PCI_INTERRUPT_VALID(sc->pl_links[i].l_irq))
544 				sc->pl_links[i].l_routed = TRUE;
545 	if (boothowto & AB_VERBOSE) {
546 		printf("%s: Links after disable:\n", sc->pl_name);
547 		acpi_pci_link_dump(sc);
548 	}
549 	ACPI_SERIAL_END(pci_link);
550 	return (0);
551 fail:
552 	ACPI_SERIAL_END(pci_link);
553 	for (i = 0; i < sc->pl_num_links; i++) {
554 		if (sc->pl_links[i].l_irqs != NULL)
555 			free(sc->pl_links[i].l_irqs, M_PCI_LINK);
556 		if (sc->pl_links[i].l_devices != NULL)
557 			free(sc->pl_links[i].l_devices, M_PCI_LINK);
558 	}
559 	free(sc->pl_links, M_PCI_LINK);
560 	return (ENXIO);
561 }
562 
563 static void
564 acpi_pci_link_add_functions(struct acpi_pci_link_softc *sc, struct link *link,
565     int bus, int device, int pin)
566 {
567 	uint32_t value;
568 	uint8_t func, maxfunc, ipin;
569 	pcitag_t tag;
570 
571 	tag = pci_make_tag(acpi_softc->sc_pc, bus, device, 0);
572 	/* See if we have a valid device at function 0. */
573 	value = pci_conf_read(acpi_softc->sc_pc, tag,  PCI_BHLC_REG);
574 	if (PCI_HDRTYPE_TYPE(value) > PCI_HDRTYPE_PCB)
575 		return;
576 	if (PCI_HDRTYPE_MULTIFN(value))
577 		maxfunc = 7;
578 	else
579 		maxfunc = 0;
580 
581 	/* Scan all possible functions at this device. */
582 	for (func = 0; func <= maxfunc; func++) {
583 		tag = pci_make_tag(acpi_softc->sc_pc, bus, device, func);
584 		value = pci_conf_read(acpi_softc->sc_pc, tag, PCI_ID_REG);
585 		if (PCI_VENDOR(value) == 0xffff)
586 			continue;
587 		value = pci_conf_read(acpi_softc->sc_pc, tag,
588 		    PCI_INTERRUPT_REG);
589 		ipin = PCI_INTERRUPT_PIN(value);
590 		/*
591 		 * See if it uses the pin in question.  Note that the passed
592 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
593 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
594 		 */
595 		if (ipin != pin + 1)
596 			continue;
597 
598 		link->l_devices = realloc(link->l_devices,
599 		    sizeof(pcitag_t) * (link->l_dev_count + 1),
600 		    M_PCI_LINK, M_WAITOK);
601 		link->l_devices[link->l_dev_count] = tag;
602 		++link->l_dev_count;
603 	}
604 }
605 
606 static uint8_t
607 acpi_pci_link_search_irq(struct acpi_pci_link_softc *sc, int bus, int device,
608 			 int pin)
609 {
610 	uint32_t value;
611 	uint8_t func, maxfunc, ipin, iline;
612 	pcitag_t tag;
613 
614 	tag = pci_make_tag(acpi_softc->sc_pc, bus, device, 0);
615 	/* See if we have a valid device at function 0. */
616 	value = pci_conf_read(acpi_softc->sc_pc, tag,  PCI_BHLC_REG);
617 	if (PCI_HDRTYPE_TYPE(value) > PCI_HDRTYPE_PCB)
618 		return (PCI_INVALID_IRQ);
619 	if (PCI_HDRTYPE_MULTIFN(value))
620 		maxfunc = 7;
621 	else
622 		maxfunc = 0;
623 
624 	/* Scan all possible functions at this device. */
625 	for (func = 0; func <= maxfunc; func++) {
626 		tag = pci_make_tag(acpi_softc->sc_pc, bus, device, func);
627 		value = pci_conf_read(acpi_softc->sc_pc, tag, PCI_ID_REG);
628 		if (PCI_VENDOR(value) == 0xffff)
629 			continue;
630 		value = pci_conf_read(acpi_softc->sc_pc, tag,
631 		    PCI_INTERRUPT_REG);
632 		ipin = PCI_INTERRUPT_PIN(value);
633 		iline = PCI_INTERRUPT_LINE(value);
634 
635 		/*
636 		 * See if it uses the pin in question.  Note that the passed
637 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
638 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
639 		 */
640 		if (ipin != pin + 1)
641 			continue;
642 		aprint_verbose(
643 		    "%s: ACPI: Found matching pin for %d.%d.INT%c"
644 	            " at func %d: %d\n",
645 			    sc->pl_name, bus, device, pin + 'A', func, iline);
646 		if (PCI_INTERRUPT_VALID(iline))
647 			return (iline);
648 	}
649 	return (PCI_INVALID_IRQ);
650 }
651 
652 /*
653  * Find the link structure that corresponds to the resource index passed in
654  * via 'source_index'.
655  */
656 static struct link *
657 acpi_pci_link_lookup(struct acpi_pci_link_softc *sc, int source_index)
658 {
659 	int i;
660 
661 	for (i = 0; i < sc->pl_num_links; i++)
662 		if (sc->pl_links[i].l_res_index == source_index)
663 			return (&sc->pl_links[i]);
664 	return (NULL);
665 }
666 
667 void
668 acpi_pci_link_add_reference(void *v, int index, int bus, int slot, int pin)
669 {
670 	struct acpi_pci_link_softc *sc = v;
671 	struct link *link;
672 	uint8_t bios_irq;
673 
674 	/* Bump the reference count. */
675 	ACPI_SERIAL_BEGIN(pci_link);
676 	link = acpi_pci_link_lookup(sc, index);
677 	if (link == NULL) {
678 		printf("%s: apparently invalid index %d\n", sc->pl_name, index);
679 		ACPI_SERIAL_END(pci_link);
680 		return;
681 	}
682 	link->l_references++;
683 	acpi_pci_link_add_functions(sc, link, bus, slot, pin);
684 	if (link->l_routed)
685 		pci_link_interrupt_weights[link->l_irq]++;
686 
687 	/*
688 	 * The BIOS only routes interrupts via ISA IRQs using the ATPICs
689 	 * (8259As).  Thus, if this link is routed via an ISA IRQ, go
690 	 * look to see if the BIOS routed an IRQ for this link at the
691 	 * indicated (bus, slot, pin).  If so, we prefer that IRQ for
692 	 * this link and add that IRQ to our list of known-good IRQs.
693 	 * This provides a good work-around for link devices whose _CRS
694 	 * method is either broken or bogus.  We only use the value
695 	 * returned by _CRS if we can't find a valid IRQ via this method
696 	 * in fact.
697 	 *
698 	 * If this link is not routed via an ISA IRQ (because we are using
699 	 * APIC for example), then don't bother looking up the BIOS IRQ
700 	 * as if we find one it won't be valid anyway.
701 	 */
702 	if (!link->l_isa_irq) {
703 		ACPI_SERIAL_END(pci_link);
704 		return;
705 	}
706 
707 	/* Try to find a BIOS IRQ setting from any matching devices. */
708 	bios_irq = acpi_pci_link_search_irq(sc, bus, slot, pin);
709 	if (!PCI_INTERRUPT_VALID(bios_irq)) {
710 		ACPI_SERIAL_END(pci_link);
711 		return;
712 	}
713 
714 	/* Validate the BIOS IRQ. */
715 	if (!link_valid_irq(link, bios_irq)) {
716 		printf("%s: BIOS IRQ %u for %d.%d.INT%c is invalid\n",
717 		    sc->pl_name, bios_irq, (int)bus, slot, pin + 'A');
718 	} else if (!PCI_INTERRUPT_VALID(link->l_bios_irq)) {
719 		link->l_bios_irq = bios_irq;
720 		if (bios_irq < NUM_ISA_INTERRUPTS)
721 			pci_link_bios_isa_irqs |= (1 << bios_irq);
722 		if (bios_irq != link->l_initial_irq &&
723 		    PCI_INTERRUPT_VALID(link->l_initial_irq))
724 			printf(
725 			    "%s: BIOS IRQ %u does not match initial IRQ %u\n",
726 			    sc->pl_name, bios_irq, link->l_initial_irq);
727 	} else if (bios_irq != link->l_bios_irq)
728 		printf(
729 	    "%s: BIOS IRQ %u for %d.%d.INT%c does not match "
730 	    "previous BIOS IRQ %u\n",
731 		    sc->pl_name, bios_irq, (int)bus, slot, pin + 'A',
732 		    link->l_bios_irq);
733 	ACPI_SERIAL_END(pci_link);
734 }
735 
736 static ACPI_STATUS
737 acpi_pci_link_srs_from_crs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
738 {
739 	ACPI_RESOURCE *resource, *end, newres, *resptr;
740 	ACPI_BUFFER crsbuf;
741 	ACPI_STATUS status;
742 	struct link *link;
743 	int i, in_dpf;
744 
745 	/* Fetch the _CRS. */
746 	crsbuf.Pointer = NULL;
747 	crsbuf.Length = ACPI_ALLOCATE_BUFFER;
748 	status = AcpiGetCurrentResources(sc->pl_handle, &crsbuf);
749 	if (ACPI_SUCCESS(status) && crsbuf.Pointer == NULL)
750 		status = AE_NO_MEMORY;
751 	if (ACPI_FAILURE(status)) {
752 		aprint_verbose("%s: Unable to fetch current resources: %s\n",
753 		    sc->pl_name, AcpiFormatException(status));
754 		return (status);
755 	}
756 
757 	/* Fill in IRQ resources via link structures. */
758 	srsbuf->Pointer = NULL;
759 	link = sc->pl_links;
760 	i = 0;
761 	in_dpf = DPF_OUTSIDE;
762 	resource = (ACPI_RESOURCE *)crsbuf.Pointer;
763 	end = (ACPI_RESOURCE *)((char *)crsbuf.Pointer + crsbuf.Length);
764 	for (;;) {
765 		switch (resource->Type) {
766 		case ACPI_RESOURCE_TYPE_START_DEPENDENT:
767 			switch (in_dpf) {
768 			case DPF_OUTSIDE:
769 				/* We've started the first DPF. */
770 				in_dpf = DPF_FIRST;
771 				break;
772 			case DPF_FIRST:
773 				/* We've started the second DPF. */
774 				panic(
775 		"%s: Multiple dependent functions within a current resource",
776 				    __func__);
777 				break;
778 			}
779 			resptr = NULL;
780 			break;
781 		case ACPI_RESOURCE_TYPE_END_DEPENDENT:
782 			/* We are finished with DPF parsing. */
783 			KASSERT(in_dpf != DPF_OUTSIDE);
784 			in_dpf = DPF_OUTSIDE;
785 			resptr = NULL;
786 			break;
787 		case ACPI_RESOURCE_TYPE_IRQ:
788 			newres = link->l_prs_template;
789 			resptr = &newres;
790 			resptr->Data.Irq.InterruptCount = 1;
791 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
792 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS);
793 				resptr->Data.Irq.Interrupts[0] = link->l_irq;
794 				resptr->Data.Irq.Triggering = link->l_trig;
795 				resptr->Data.Irq.Polarity = link->l_pol;
796 			} else
797 				resptr->Data.Irq.Interrupts[0] = 0;
798 			link++;
799 			i++;
800 			break;
801 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
802 			newres = link->l_prs_template;
803 			resptr = &newres;
804 			resptr->Data.ExtendedIrq.InterruptCount = 1;
805 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
806 				resptr->Data.ExtendedIrq.Interrupts[0] =
807 				    link->l_irq;
808 				resptr->Data.ExtendedIrq.Triggering =
809 				    link->l_trig;
810 				resptr->Data.ExtendedIrq.Polarity = link->l_pol;
811 			} else
812 				resptr->Data.ExtendedIrq.Interrupts[0] = 0;
813 			link++;
814 			i++;
815 			break;
816 		default:
817 			resptr = resource;
818 		}
819 		if (resptr != NULL) {
820 			status = acpi_AppendBufferResource(srsbuf, resptr);
821 			if (ACPI_FAILURE(status)) {
822 				printf("%s: Unable to build resources: %s\n",
823 				    sc->pl_name, AcpiFormatException(status));
824 				if (srsbuf->Pointer != NULL)
825 					AcpiOsFree(srsbuf->Pointer);
826 				AcpiOsFree(crsbuf.Pointer);
827 				return (status);
828 			}
829 		}
830 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
831 			break;
832 		resource = ACPI_NEXT_RESOURCE(resource);
833 		if (resource >= end)
834 			break;
835 	}
836 	AcpiOsFree(crsbuf.Pointer);
837 	return (AE_OK);
838 }
839 
840 static ACPI_STATUS
841 acpi_pci_link_srs_from_links(struct acpi_pci_link_softc *sc,
842     ACPI_BUFFER *srsbuf)
843 {
844 	ACPI_RESOURCE newres;
845 	ACPI_STATUS status;
846 	struct link *link;
847 	int i;
848 
849 	/* Start off with an empty buffer. */
850 	srsbuf->Pointer = NULL;
851 	link = sc->pl_links;
852 	for (i = 0; i < sc->pl_num_links; i++) {
853 
854 		/* Add a new IRQ resource from each link. */
855 		link = &sc->pl_links[i];
856 		newres = link->l_prs_template;
857 		if (newres.Type == ACPI_RESOURCE_TYPE_IRQ) {
858 
859 			/* Build an IRQ resource. */
860 			newres.Data.Irq.InterruptCount = 1;
861 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
862 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS);
863 				newres.Data.Irq.Interrupts[0] = link->l_irq;
864 				newres.Data.Irq.Triggering = link->l_trig;
865 				newres.Data.Irq.Polarity = link->l_pol;
866 			} else
867 				newres.Data.Irq.Interrupts[0] = 0;
868 		} else {
869 
870 			/* Build an ExtIRQ resuorce. */
871 			newres.Data.ExtendedIrq.InterruptCount = 1;
872 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
873 				newres.Data.ExtendedIrq.Interrupts[0] =
874 				    link->l_irq;
875 				newres.Data.ExtendedIrq.Triggering =
876 				    link->l_trig;
877 				newres.Data.ExtendedIrq.Polarity =
878 				    link->l_pol;
879 			} else {
880 				newres.Data.ExtendedIrq.Interrupts[0] = 0;
881 			}
882 		}
883 
884 		/* Add the new resource to the end of the _SRS buffer. */
885 		status = acpi_AppendBufferResource(srsbuf, &newres);
886 		if (ACPI_FAILURE(status)) {
887 			printf("%s: Unable to build resources: %s\n",
888 			    sc->pl_name, AcpiFormatException(status));
889 			if (srsbuf->Pointer != NULL)
890 				AcpiOsFree(srsbuf->Pointer);
891 			return (status);
892 		}
893 	}
894 	return (AE_OK);
895 }
896 
897 static ACPI_STATUS
898 acpi_pci_link_srs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
899 {
900 	ACPI_STATUS status;
901 
902 	if (sc->pl_crs_bad)
903 		status = acpi_pci_link_srs_from_links(sc, srsbuf);
904 	else
905 		status = acpi_pci_link_srs_from_crs(sc, srsbuf);
906 
907 	/* Write out new resources via _SRS. */
908 	return AcpiSetCurrentResources(sc->pl_handle, srsbuf);
909 }
910 
911 static ACPI_STATUS
912 acpi_pci_link_route_irqs(struct acpi_pci_link_softc *sc, int *irq, int *pol,
913 			 int *trig)
914 {
915 	ACPI_RESOURCE *resource, *end;
916 	ACPI_BUFFER srsbuf;
917 	ACPI_STATUS status;
918 	struct link *link;
919 	int i, is_ext = 0;
920 
921 	status = acpi_pci_link_srs(sc, &srsbuf);
922 	if (ACPI_FAILURE(status)) {
923 		printf("%s: _SRS failed: %s\n",
924 		    sc->pl_name, AcpiFormatException(status));
925 		return (status);
926 	}
927 	/*
928 	 * Perform acpi_config_intr() on each IRQ resource if it was just
929 	 * routed for the first time.
930 	 */
931 	link = sc->pl_links;
932 	i = 0;
933 	resource = (ACPI_RESOURCE *)srsbuf.Pointer;
934 	end = (ACPI_RESOURCE *)((char *)srsbuf.Pointer + srsbuf.Length);
935 	for (;;) {
936 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
937 			break;
938 		switch (resource->Type) {
939 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
940 			is_ext = 1;
941 			/* FALLTHROUGH */
942 		case ACPI_RESOURCE_TYPE_IRQ:
943 			/*
944 			 * Only configure the interrupt and update the
945 			 * weights if this link has a valid IRQ and was
946 			 * previously unrouted.
947 			 */
948 			if (!link->l_routed &&
949 			    PCI_INTERRUPT_VALID(link->l_irq)) {
950 				*trig = is_ext ?
951 				    resource->Data.ExtendedIrq.Triggering :
952 				    resource->Data.Irq.Triggering;
953 				*pol = is_ext ?
954 				    resource->Data.ExtendedIrq.Polarity :
955 				    resource->Data.Irq.Polarity;
956 				*irq = is_ext ?
957 				    resource->Data.ExtendedIrq.Interrupts[0] :
958 				    resource->Data.Irq.Interrupts[0];
959 				link->l_routed = TRUE;
960 				pci_link_interrupt_weights[link->l_irq] +=
961 				    link->l_references;
962 			}
963 			link++;
964 			i++;
965 			break;
966 		}
967 		resource = ACPI_NEXT_RESOURCE(resource);
968 		if (resource >= end)
969 			break;
970 	}
971 	AcpiOsFree(srsbuf.Pointer);
972 	return (AE_OK);
973 }
974 
975 static void
976 acpi_pci_link_resume(int why, void *arg)
977 {
978 	struct acpi_pci_link_softc *sc = arg;
979 	ACPI_BUFFER srsbuf;
980 
981 	switch (why) {
982 	case PWR_RESUME:
983 		ACPI_SERIAL_BEGIN(pci_link);
984 		if (ACPI_SUCCESS(acpi_pci_link_srs(sc, &srsbuf)))
985 			AcpiOsFree(srsbuf.Pointer);
986 		ACPI_SERIAL_END(pci_link);
987 	default:
988 		break;
989 	}
990 }
991 
992 /*
993  * Pick an IRQ to use for this unrouted link.
994  */
995 static uint8_t
996 acpi_pci_link_choose_irq(struct acpi_pci_link_softc *sc, struct link *link)
997 {
998 	u_int8_t best_irq, pos_irq;
999 	int best_weight, pos_weight, i;
1000 
1001 	KASSERT(!link->l_routed);
1002 	KASSERT(!PCI_INTERRUPT_VALID(link->l_irq));
1003 
1004 	/*
1005 	 * If we have a valid BIOS IRQ, use that.  We trust what the BIOS
1006 	 * says it routed over what _CRS says the link thinks is routed.
1007 	 */
1008 	if (PCI_INTERRUPT_VALID(link->l_bios_irq))
1009 		return (link->l_bios_irq);
1010 
1011 	/*
1012 	 * If we don't have a BIOS IRQ but do have a valid IRQ from _CRS,
1013 	 * then use that.
1014 	 */
1015 	if (PCI_INTERRUPT_VALID(link->l_initial_irq))
1016 		return (link->l_initial_irq);
1017 
1018 	/*
1019 	 * Ok, we have no useful hints, so we have to pick from the
1020 	 * possible IRQs.  For ISA IRQs we only use interrupts that
1021 	 * have already been used by the BIOS.
1022 	 */
1023 	best_irq = PCI_INVALID_IRQ;
1024 	best_weight = INT_MAX;
1025 	for (i = 0; i < link->l_num_irqs; i++) {
1026 		pos_irq = link->l_irqs[i];
1027 		if (pos_irq < NUM_ISA_INTERRUPTS &&
1028 		    (pci_link_bios_isa_irqs & 1 << pos_irq) == 0)
1029 			continue;
1030 		pos_weight = pci_link_interrupt_weights[pos_irq];
1031 		if (pos_weight < best_weight) {
1032 			best_weight = pos_weight;
1033 			best_irq = pos_irq;
1034 		}
1035 	}
1036 
1037 	/*
1038 	 * If this is an ISA IRQ, try using the SCI if it is also an ISA
1039 	 * interrupt as a fallback.
1040 	 */
1041 	if (link->l_isa_irq && !PCI_INTERRUPT_VALID(best_irq)) {
1042 		pos_irq = AcpiGbl_FADT.SciInterrupt;
1043 		pos_weight = pci_link_interrupt_weights[pos_irq];
1044 		if (pos_weight < best_weight) {
1045 			best_weight = pos_weight;
1046 			best_irq = pos_irq;
1047 		}
1048 	}
1049 
1050 	if (PCI_INTERRUPT_VALID(best_irq)) {
1051 		aprint_verbose("%s: Picked IRQ %u with weight %d\n",
1052 		    sc->pl_name, best_irq, best_weight);
1053 	} else
1054 		printf("%s: Unable to choose an IRQ\n", sc->pl_name);
1055 	return (best_irq);
1056 }
1057 
1058 int
1059 acpi_pci_link_route_interrupt(void *v, int index, int *irq, int *pol, int *trig)
1060 {
1061 	struct acpi_pci_link_softc *sc = v;
1062 	struct link *link;
1063 	int i;
1064 	pcireg_t reg;
1065 
1066 	ACPI_SERIAL_BEGIN(pci_link);
1067 	link = acpi_pci_link_lookup(sc, index);
1068 	if (link == NULL)
1069 		panic("%s: apparently invalid index %d", __func__, index);
1070 
1071 	/*
1072 	 * If this link device is already routed to an interrupt, just return
1073 	 * the interrupt it is routed to.
1074 	 */
1075 	if (link->l_routed) {
1076 		KASSERT(PCI_INTERRUPT_VALID(link->l_irq));
1077 		ACPI_SERIAL_END(pci_link);
1078 		*irq = link->l_irq;
1079 		*pol = link->l_pol;
1080 		*trig = link->l_trig;
1081 		return (link->l_irq);
1082 	}
1083 
1084 	/* Choose an IRQ if we need one. */
1085 	if (PCI_INTERRUPT_VALID(link->l_irq))
1086 		goto done;
1087 
1088 	link->l_irq = acpi_pci_link_choose_irq(sc, link);
1089 
1090 	/*
1091 	 * Try to route the interrupt we picked.  If it fails, then
1092 	 * assume the interrupt is not routed.
1093 	 */
1094 	if (!PCI_INTERRUPT_VALID(link->l_irq))
1095 		goto done;
1096 
1097 	acpi_pci_link_route_irqs(sc, irq, pol, trig);
1098 	if (!link->l_routed) {
1099 		link->l_irq = PCI_INVALID_IRQ;
1100 		goto done;
1101 	}
1102 
1103 	link->l_pol = *pol;
1104 	link->l_trig = *trig;
1105 	for (i = 0; i < link->l_dev_count; ++i) {
1106 		reg = pci_conf_read(acpi_softc->sc_pc, link->l_devices[i],
1107 		    PCI_INTERRUPT_REG);
1108 		reg &= ~(PCI_INTERRUPT_LINE_MASK << PCI_INTERRUPT_LINE_SHIFT);
1109 		reg |= link->l_irq << PCI_INTERRUPT_LINE_SHIFT;
1110 		pci_conf_write(acpi_softc->sc_pc, link->l_devices[i],
1111 		    PCI_INTERRUPT_REG, reg);
1112 	}
1113 
1114 done:
1115 	ACPI_SERIAL_END(pci_link);
1116 
1117 	return (link->l_irq);
1118 }
1119 
1120 /*
1121  * This is gross, but we abuse the identify routine to perform one-time
1122  * SYSINIT() style initialization for the driver.
1123  */
1124 static void
1125 acpi_pci_link_init(struct acpi_pci_link_softc *sc)
1126 {
1127 	ACPI_BUFFER buf;
1128 	char acpipcilinkname[] = "acpi_pci_link";
1129 
1130 	/*
1131 	 * If the SCI is an ISA IRQ, add it to the bitmask of known good
1132 	 * ISA IRQs.
1133 	 *
1134 	 * XXX: If we are using the APIC, the SCI might have been
1135 	 * rerouted to an APIC pin in which case this is invalid.  However,
1136 	 * if we are using the APIC, we also shouldn't be having any PCI
1137 	 * interrupts routed via ISA IRQs, so this is probably ok.
1138 	 */
1139 	if (AcpiGbl_FADT.SciInterrupt < NUM_ISA_INTERRUPTS)
1140 		pci_link_bios_isa_irqs |= (1 << AcpiGbl_FADT.SciInterrupt);
1141 
1142         sc->pl_powerhook = powerhook_establish(acpipcilinkname,
1143 	    acpi_pci_link_resume, sc);
1144         if (sc->pl_powerhook == NULL)
1145                 aprint_normal("can't establish powerhook\n");
1146 
1147 	buf.Length = sizeof (sc->pl_name);
1148 	buf.Pointer = sc->pl_name;
1149 
1150 	if (ACPI_FAILURE(AcpiGetName(sc->pl_handle, ACPI_SINGLE_NAME, &buf)))
1151 		snprintf(sc->pl_name, sizeof (sc->pl_name), "%s",
1152 		    "ACPI link device");
1153 
1154 	acpi_pci_link_attach(sc);
1155 }
1156 
1157 void *
1158 acpi_pci_link_devbyhandle(ACPI_HANDLE handle)
1159 {
1160 	struct acpi_pci_link_softc *sc;
1161 
1162 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
1163 		if (sc->pl_handle == handle)
1164 			return sc;
1165 	}
1166 
1167 	sc = malloc(sizeof (*sc), M_PCI_LINK, M_NOWAIT|M_ZERO);
1168 	if (sc == NULL)
1169 		return NULL;
1170 
1171 	sc->pl_handle = handle;
1172 
1173 	acpi_pci_link_init(sc);
1174 
1175 	TAILQ_INSERT_TAIL(&acpi_pci_linkdevs, sc, pl_list);
1176 
1177 	return (void *)sc;
1178 }
1179 
1180 ACPI_HANDLE
1181 acpi_pci_link_handle(void *v)
1182 {
1183 	struct acpi_pci_link_softc *sc = v;
1184 
1185 	return sc->pl_handle;
1186 }
1187 
1188 char *
1189 acpi_pci_link_name(void *v)
1190 {
1191 	struct acpi_pci_link_softc *sc = v;
1192 
1193 	return sc->pl_name;
1194 }
1195 
1196 
1197 /*
1198  * Append an ACPI_RESOURCE to an ACPI_BUFFER.
1199  *
1200  * Given a pointer to an ACPI_RESOURCE structure, expand the ACPI_BUFFER
1201  * provided to contain it.  If the ACPI_BUFFER is empty, allocate a sensible
1202  * backing block.  If the ACPI_RESOURCE is NULL, return an empty set of
1203  * resources.
1204  */
1205 #define ACPI_INITIAL_RESOURCE_BUFFER_SIZE	512
1206 
1207 static ACPI_STATUS
1208 acpi_AppendBufferResource(ACPI_BUFFER *buf, ACPI_RESOURCE *res)
1209 {
1210 	ACPI_RESOURCE	*rp;
1211 	void		*newp;
1212 
1213 	/* Initialise the buffer if necessary. */
1214 	if (buf->Pointer == NULL) {
1215 	buf->Length = ACPI_INITIAL_RESOURCE_BUFFER_SIZE;
1216 	if ((buf->Pointer = AcpiOsAllocate(buf->Length)) == NULL)
1217 		return (AE_NO_MEMORY);
1218 	rp = (ACPI_RESOURCE *)buf->Pointer;
1219 	rp->Type =  ACPI_RESOURCE_TYPE_END_TAG;
1220 	rp->Length = 0;
1221 	}
1222 
1223 	if (res == NULL)
1224 		return (AE_OK);
1225 
1226 	/*
1227 	 * Scan the current buffer looking for the terminator.
1228 	 * This will either find the terminator or hit the end
1229 	 * of the buffer and return an error.
1230 	 */
1231 	rp = (ACPI_RESOURCE *)buf->Pointer;
1232 	for (;;) {
1233 		/* Range check, don't go outside the buffer */
1234 		if (rp >= (ACPI_RESOURCE *)((u_int8_t *)buf->Pointer +
1235 		    buf->Length))
1236 			return (AE_BAD_PARAMETER);
1237 		if (rp->Type ==  ACPI_RESOURCE_TYPE_END_TAG || rp->Length == 0)
1238 			break;
1239 		rp = ACPI_NEXT_RESOURCE(rp);
1240 	}
1241 
1242 	/*
1243 	 * Check the size of the buffer and expand if required.
1244 	 *
1245 	 * Required size is:
1246 	 *	size of existing resources before terminator +
1247 	 *	size of new resource and header +
1248 	 * 	size of terminator.
1249 	 *
1250 	 * Note that this loop should really only run once, unless
1251 	 * for some reason we are stuffing a *really* huge resource.
1252 	 */
1253 	while ((((u_int8_t *)rp - (u_int8_t *)buf->Pointer) +
1254 	    res->Length + ACPI_RS_SIZE_NO_DATA +
1255 	    ACPI_RS_SIZE_MIN) >= buf->Length) {
1256 		if ((newp = AcpiOsAllocate(buf->Length * 2)) == NULL)
1257 			return (AE_NO_MEMORY);
1258 		memcpy(newp, buf->Pointer, buf->Length);
1259 		rp = (ACPI_RESOURCE *)((u_int8_t *)newp +
1260 		   ((u_int8_t *)rp - (u_int8_t *)buf->Pointer));
1261 		AcpiOsFree(buf->Pointer);
1262 		buf->Pointer = newp;
1263 		buf->Length += buf->Length;
1264 	}
1265 
1266 	/* Insert the new resource. */
1267 	memcpy(rp, res, res->Length + ACPI_RS_SIZE_NO_DATA);
1268 
1269 	/* And add the terminator. */
1270 	rp = ACPI_NEXT_RESOURCE(rp);
1271 	rp->Type =  ACPI_RESOURCE_TYPE_END_TAG;
1272 	rp->Length = 0;
1273 
1274 	return (AE_OK);
1275 }
1276