xref: /netbsd-src/sys/dev/acpi/acpi_pci_link.c (revision ba65fde2d7fefa7d39838fa5fa855e62bd606b5e)
1 /*	$NetBSD: acpi_pci_link.c,v 1.19 2012/09/23 00:26:25 chs 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 1.19 2012/09/23 00:26:25 chs Exp $");
31 
32 #include <sys/param.h>
33 #include <sys/malloc.h>
34 #include <sys/queue.h>
35 #include <sys/reboot.h>
36 #include <sys/systm.h>
37 
38 #include <dev/acpi/acpireg.h>
39 #include <dev/acpi/acpivar.h>
40 
41 #include <dev/pci/pcireg.h>
42 
43 #include "opt_acpi.h"
44 
45 
46 #define _COMPONENT          ACPI_BUS_COMPONENT
47 ACPI_MODULE_NAME            ("acpi_pci_link")
48 
49 MALLOC_DECLARE(M_ACPI);
50 
51 #define NUM_ISA_INTERRUPTS	16
52 #define NUM_ACPI_INTERRUPTS	256
53 
54 #define PCI_INVALID_IRQ	255
55 #define PCI_INTERRUPT_VALID(x) ((x) != PCI_INVALID_IRQ && (x) != 0)
56 
57 #define ACPI_SERIAL_BEGIN(x)
58 #define ACPI_SERIAL_END(x)
59 
60 /*
61  * An ACPI PCI link device may contain multiple links.  Each link has its
62  * own ACPI resource.  _PRT entries specify which link is being used via
63  * the Source Index.
64  *
65  * XXX: A note about Source Indices and DPFs:  Currently we assume that
66  * the DPF start and end tags are not counted towards the index that
67  * Source Index corresponds to.  Also, we assume that when DPFs are in use
68  * they various sets overlap in terms of Indices.  Here's an example
69  * resource list indicating these assumptions:
70  *
71  * Resource		Index
72  * --------		-----
73  * I/O Port		0
74  * Start DPF		-
75  * IRQ			1
76  * MemIO		2
77  * Start DPF		-
78  * IRQ			1
79  * MemIO		2
80  * End DPF		-
81  * DMA Channel		3
82  *
83  * The XXX is because I'm not sure if this is a valid assumption to make.
84  */
85 
86 /* States during DPF processing. */
87 #define	DPF_OUTSIDE	0
88 #define	DPF_FIRST	1
89 #define	DPF_IGNORE	2
90 
91 struct link;
92 
93 struct acpi_pci_link_softc {
94 	int	pl_num_links;
95 	int	pl_crs_bad;
96 	struct link *pl_links;
97 	char pl_name[32];
98 	ACPI_HANDLE pl_handle;
99 	TAILQ_ENTRY(acpi_pci_link_softc) pl_list;
100 };
101 
102 static TAILQ_HEAD(, acpi_pci_link_softc) acpi_pci_linkdevs =
103     TAILQ_HEAD_INITIALIZER(acpi_pci_linkdevs);
104 
105 
106 struct link {
107 	struct acpi_pci_link_softc *l_sc;
108 	uint8_t	l_bios_irq;
109 	uint8_t	l_irq;
110 	uint8_t l_trig;
111 	uint8_t l_pol;
112 	uint8_t	l_initial_irq;
113 	int	l_res_index;
114 	int	l_num_irqs;
115 	int	*l_irqs;
116 	int	l_references;
117 	int	l_dev_count;
118 	pcitag_t *l_devices;
119 	int	l_routed:1;
120 	int	l_isa_irq:1;
121 	ACPI_RESOURCE l_prs_template;
122 };
123 
124 struct link_count_request {
125 	int	in_dpf;
126 	int	count;
127 };
128 
129 struct link_res_request {
130 	struct acpi_pci_link_softc *sc;
131 	int	in_dpf;
132 	int	res_index;
133 	int	link_index;
134 };
135 
136 static int pci_link_interrupt_weights[NUM_ACPI_INTERRUPTS];
137 static int pci_link_bios_isa_irqs;
138 
139 static ACPI_STATUS acpi_count_irq_resources(ACPI_RESOURCE *, void *);
140 static ACPI_STATUS link_add_crs(ACPI_RESOURCE *, void *);
141 static ACPI_STATUS link_add_prs(ACPI_RESOURCE *, void *);
142 static int link_valid_irq(struct link *, int);
143 static void acpi_pci_link_dump(struct acpi_pci_link_softc *);
144 static int acpi_pci_link_attach(struct acpi_pci_link_softc *);
145 static uint8_t acpi_pci_link_search_irq(struct acpi_pci_link_softc *, int, int,
146 					int);
147 static struct link *acpi_pci_link_lookup(struct acpi_pci_link_softc *, int);
148 static ACPI_STATUS acpi_pci_link_srs(struct acpi_pci_link_softc *,
149 				     ACPI_BUFFER *);
150 static ACPI_STATUS acpi_AppendBufferResource(ACPI_BUFFER *, ACPI_RESOURCE *);
151 
152 static ACPI_STATUS
153 acpi_count_irq_resources(ACPI_RESOURCE *res, void *context)
154 {
155 	struct link_count_request *req;
156 
157 	req = (struct link_count_request *)context;
158 	switch (res->Type) {
159 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
160 		switch (req->in_dpf) {
161 		case DPF_OUTSIDE:
162 			/* We've started the first DPF. */
163 			req->in_dpf = DPF_FIRST;
164 			break;
165 		case DPF_FIRST:
166 			/* We've started the second DPF. */
167 			req->in_dpf = DPF_IGNORE;
168 			break;
169 		}
170 		break;
171 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
172 		/* We are finished with DPF parsing. */
173 		KASSERT(req->in_dpf != DPF_OUTSIDE);
174 		req->in_dpf = DPF_OUTSIDE;
175 		break;
176 	case ACPI_RESOURCE_TYPE_IRQ:
177 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
178 		/*
179 		 * Don't count resources if we are in a DPF set that we are
180 		 * ignoring.
181 		 */
182 		if (req->in_dpf != DPF_IGNORE)
183 			req->count++;
184 	}
185 	return (AE_OK);
186 }
187 
188 static ACPI_STATUS
189 link_add_crs(ACPI_RESOURCE *res, void *context)
190 {
191 	struct link_res_request *req;
192 	struct link *link;
193 
194 	req = (struct link_res_request *)context;
195 	switch (res->Type) {
196 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
197 		switch (req->in_dpf) {
198 		case DPF_OUTSIDE:
199 			/* We've started the first DPF. */
200 			req->in_dpf = DPF_FIRST;
201 			break;
202 		case DPF_FIRST:
203 			/* We've started the second DPF. */
204 			panic(
205 		"%s: Multiple dependent functions within a current resource",
206 			    __func__);
207 			break;
208 		}
209 		break;
210 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
211 		/* We are finished with DPF parsing. */
212 		KASSERT(req->in_dpf != DPF_OUTSIDE);
213 		req->in_dpf = DPF_OUTSIDE;
214 		break;
215 	case ACPI_RESOURCE_TYPE_IRQ:
216 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
217 		KASSERT(req->link_index < req->sc->pl_num_links);
218 		link = &req->sc->pl_links[req->link_index];
219 		link->l_res_index = req->res_index;
220 		req->link_index++;
221 		req->res_index++;
222 
223 		/*
224 		 * Only use the current value if there's one IRQ.  Some
225 		 * systems return multiple IRQs (which is nonsense for _CRS)
226 		 * when the link hasn't been programmed.
227 		 */
228 		if (res->Type == ACPI_RESOURCE_TYPE_IRQ) {
229 			if (res->Data.Irq.InterruptCount == 1) {
230 				link->l_irq = res->Data.Irq.Interrupts[0];
231 				link->l_trig = res->Data.Irq.Triggering;
232 				link->l_pol = res->Data.Irq.Polarity;
233 			}
234 		} else if (res->Data.ExtendedIrq.InterruptCount == 1) {
235 			link->l_irq = res->Data.ExtendedIrq.Interrupts[0];
236 			link->l_trig = res->Data.ExtendedIrq.Triggering;
237 			link->l_pol = res->Data.ExtendedIrq.Polarity;
238 		}
239 
240 		/*
241 		 * An IRQ of zero means that the link isn't routed.
242 		 */
243 		if (link->l_irq == 0)
244 			link->l_irq = PCI_INVALID_IRQ;
245 		break;
246 	default:
247 		req->res_index++;
248 	}
249 	return (AE_OK);
250 }
251 
252 /*
253  * Populate the set of possible IRQs for each device.
254  */
255 static ACPI_STATUS
256 link_add_prs(ACPI_RESOURCE *res, void *context)
257 {
258 	struct link_res_request *req;
259 	struct link *link;
260 	uint8_t *irqs = NULL;
261 	uint32_t *ext_irqs = NULL;
262 	int i, is_ext_irq = 1;
263 
264 	req = (struct link_res_request *)context;
265 	switch (res->Type) {
266 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
267 		switch (req->in_dpf) {
268 		case DPF_OUTSIDE:
269 			/* We've started the first DPF. */
270 			req->in_dpf = DPF_FIRST;
271 			break;
272 		case DPF_FIRST:
273 			/* We've started the second DPF. */
274 			req->in_dpf = DPF_IGNORE;
275 			break;
276 		}
277 		break;
278 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
279 		/* We are finished with DPF parsing. */
280 		KASSERT(req->in_dpf != DPF_OUTSIDE);
281 		req->in_dpf = DPF_OUTSIDE;
282 		break;
283 	case ACPI_RESOURCE_TYPE_IRQ:
284 		is_ext_irq = 0;
285 		/* fall through */
286 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
287 		/*
288 		 * Don't parse resources if we are in a DPF set that we are
289 		 * ignoring.
290 		 */
291 		if (req->in_dpf == DPF_IGNORE)
292 			break;
293 
294 		KASSERT(req->link_index < req->sc->pl_num_links);
295 		link = &req->sc->pl_links[req->link_index];
296 		if (link->l_res_index == -1) {
297 			KASSERT(req->sc->pl_crs_bad);
298 			link->l_res_index = req->res_index;
299 		}
300 		req->link_index++;
301 		req->res_index++;
302 
303 		/*
304 		 * Stash a copy of the resource for later use when
305 		 * doing _SRS.
306 		 *
307 		 * Note that in theory res->Length may exceed the size
308 		 * of ACPI_RESOURCE, due to variable length lists in
309 		 * subtypes.  However, all uses of l_prs_template only
310 		 * rely on lists lengths of zero or one, for which
311 		 * sizeof(ACPI_RESOURCE) is sufficient space anyway.
312 		 * We cannot read longer than Length bytes, in case we
313 		 * read off the end of mapped memory.  So we read
314 		 * whichever length is shortest, Length or
315 		 * sizeof(ACPI_RESOURCE).
316 		 */
317 		KASSERT(res->Length >= ACPI_RS_SIZE_MIN);
318 
319 		memset(&link->l_prs_template, 0, sizeof(link->l_prs_template));
320 		memcpy(&link->l_prs_template, res,
321 		       MIN(res->Length, sizeof(link->l_prs_template)));
322 
323 		if (is_ext_irq) {
324 			link->l_num_irqs =
325 			    res->Data.ExtendedIrq.InterruptCount;
326 			link->l_trig = res->Data.ExtendedIrq.Triggering;
327 			link->l_pol = res->Data.ExtendedIrq.Polarity;
328 			ext_irqs = res->Data.ExtendedIrq.Interrupts;
329 		} else {
330 			link->l_num_irqs = res->Data.Irq.InterruptCount;
331 			link->l_trig = res->Data.Irq.Triggering;
332 			link->l_pol = res->Data.Irq.Polarity;
333 			irqs = res->Data.Irq.Interrupts;
334 		}
335 		if (link->l_num_irqs == 0)
336 			break;
337 
338 		/*
339 		 * Save a list of the valid IRQs.  Also, if all of the
340 		 * valid IRQs are ISA IRQs, then mark this link as
341 		 * routed via an ISA interrupt.
342 		 */
343 		link->l_isa_irq = TRUE;
344 		link->l_irqs = malloc(sizeof(int) * link->l_num_irqs,
345 		    M_ACPI, M_WAITOK | M_ZERO);
346 		for (i = 0; i < link->l_num_irqs; i++) {
347 			if (is_ext_irq) {
348 				link->l_irqs[i] = ext_irqs[i];
349 				if (ext_irqs[i] >= NUM_ISA_INTERRUPTS)
350 					link->l_isa_irq = FALSE;
351 			} else {
352 				link->l_irqs[i] = irqs[i];
353 				if (irqs[i] >= NUM_ISA_INTERRUPTS)
354 					link->l_isa_irq = FALSE;
355 			}
356 		}
357 		break;
358 	default:
359 		if (req->in_dpf == DPF_IGNORE)
360 			break;
361 		if (req->sc->pl_crs_bad)
362 			aprint_normal("%s: Warning: possible resource %d "
363 			       "will be lost during _SRS\n", req->sc->pl_name,
364 			       req->res_index);
365 		req->res_index++;
366 	}
367 	return (AE_OK);
368 }
369 
370 static int
371 link_valid_irq(struct link *link, int irq)
372 {
373 	int i;
374 
375 	/* Invalid interrupts are never valid. */
376 	if (!PCI_INTERRUPT_VALID(irq))
377 		return (FALSE);
378 
379 	/* Any interrupt in the list of possible interrupts is valid. */
380 	for (i = 0; i < link->l_num_irqs; i++)
381 		if (link->l_irqs[i] == irq)
382 			 return (TRUE);
383 
384 	/*
385 	 * For links routed via an ISA interrupt, if the SCI is routed via
386 	 * an ISA interrupt, the SCI is always treated as a valid IRQ.
387 	 */
388 	if (link->l_isa_irq && AcpiGbl_FADT.SciInterrupt == irq &&
389 	    irq < NUM_ISA_INTERRUPTS)
390 		return (TRUE);
391 
392 	/* If the interrupt wasn't found in the list it is not valid. */
393 	return (FALSE);
394 }
395 
396 void
397 acpi_pci_link_state(void)
398 {
399 	struct acpi_pci_link_softc *sc;
400 
401 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
402 		acpi_pci_link_dump(sc);
403 	}
404 }
405 
406 static void
407 acpi_pci_link_dump(struct acpi_pci_link_softc *sc)
408 {
409 	struct link *link;
410 	int i, j;
411 
412 	printf("Link Device %s:\n", sc->pl_name);
413 	printf("Index  IRQ  Rtd  Ref  IRQs\n");
414 	for (i = 0; i < sc->pl_num_links; i++) {
415 		link = &sc->pl_links[i];
416 		printf("%5d  %3d   %c   %3d ", i, link->l_irq,
417 		    link->l_routed ? 'Y' : 'N',  link->l_references);
418 		if (link->l_num_irqs == 0)
419 			printf(" none");
420 		else for (j = 0; j < link->l_num_irqs; j++)
421 			printf(" %d", link->l_irqs[j]);
422 		printf(" polarity %u trigger %u\n", link->l_pol, link->l_trig);
423 	}
424 	printf("\n");
425 }
426 
427 static int
428 acpi_pci_link_attach(struct acpi_pci_link_softc *sc)
429 {
430 	struct link_count_request creq;
431 	struct link_res_request rreq;
432 	ACPI_STATUS status;
433 	int i;
434 
435 	ACPI_SERIAL_BEGIN(pci_link);
436 
437 	/*
438 	 * Count the number of current resources so we know how big of
439 	 * a link array to allocate.  On some systems, _CRS is broken,
440 	 * so for those systems try to derive the count from _PRS instead.
441 	 */
442 	creq.in_dpf = DPF_OUTSIDE;
443 	creq.count = 0;
444 	status = AcpiWalkResources(sc->pl_handle, "_CRS",
445 	    acpi_count_irq_resources, &creq);
446 	sc->pl_crs_bad = ACPI_FAILURE(status);
447 	if (sc->pl_crs_bad) {
448 		creq.in_dpf = DPF_OUTSIDE;
449 		creq.count = 0;
450 		status = AcpiWalkResources(sc->pl_handle, "_PRS",
451 		    acpi_count_irq_resources, &creq);
452 		if (ACPI_FAILURE(status)) {
453 			aprint_error("%s: Unable to parse _CRS or _PRS: %s\n",
454 			    sc->pl_name, AcpiFormatException(status));
455 			ACPI_SERIAL_END(pci_link);
456 			return (ENXIO);
457 		}
458 	}
459 	sc->pl_num_links = creq.count;
460 	if (creq.count == 0) {
461 		ACPI_SERIAL_END(pci_link);
462 		return (0);
463 	}
464 	sc->pl_links = malloc(sizeof(struct link) * sc->pl_num_links,
465 	    M_ACPI, M_WAITOK | M_ZERO);
466 
467 	/* Initialize the child links. */
468 	for (i = 0; i < sc->pl_num_links; i++) {
469 		sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
470 		sc->pl_links[i].l_bios_irq = PCI_INVALID_IRQ;
471 		sc->pl_links[i].l_sc = sc;
472 		sc->pl_links[i].l_isa_irq = FALSE;
473 		sc->pl_links[i].l_res_index = -1;
474 		sc->pl_links[i].l_dev_count = 0;
475 		sc->pl_links[i].l_devices = NULL;
476 	}
477 
478 	/* Try to read the current settings from _CRS if it is valid. */
479 	if (!sc->pl_crs_bad) {
480 		rreq.in_dpf = DPF_OUTSIDE;
481 		rreq.link_index = 0;
482 		rreq.res_index = 0;
483 		rreq.sc = sc;
484 		status = AcpiWalkResources(sc->pl_handle, "_CRS",
485 		    link_add_crs, &rreq);
486 		if (ACPI_FAILURE(status)) {
487 			aprint_error("%s: Unable to parse _CRS: %s\n",
488 			    sc->pl_name, AcpiFormatException(status));
489 			goto fail;
490 		}
491 	}
492 
493 	/*
494 	 * Try to read the possible settings from _PRS.  Note that if the
495 	 * _CRS is toast, we depend on having a working _PRS.  However, if
496 	 * _CRS works, then it is ok for _PRS to be missing.
497 	 */
498 	rreq.in_dpf = DPF_OUTSIDE;
499 	rreq.link_index = 0;
500 	rreq.res_index = 0;
501 	rreq.sc = sc;
502 	status = AcpiWalkResources(sc->pl_handle, "_PRS",
503 	    link_add_prs, &rreq);
504 	if (ACPI_FAILURE(status) &&
505 	    (status != AE_NOT_FOUND || sc->pl_crs_bad)) {
506 		aprint_error("%s: Unable to parse _PRS: %s\n",
507 		    sc->pl_name, AcpiFormatException(status));
508 		goto fail;
509 	}
510 	if (boothowto & AB_VERBOSE) {
511 		aprint_normal("%s: Links after initial probe:\n", sc->pl_name);
512 		acpi_pci_link_dump(sc);
513 	}
514 
515 	/* Verify initial IRQs if we have _PRS. */
516 	if (status != AE_NOT_FOUND)
517 		for (i = 0; i < sc->pl_num_links; i++)
518 			if (!link_valid_irq(&sc->pl_links[i],
519 			    sc->pl_links[i].l_irq))
520 				sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
521 	if (boothowto & AB_VERBOSE) {
522 		printf("%s: Links after initial validation:\n", sc->pl_name);
523 		acpi_pci_link_dump(sc);
524 	}
525 
526 	/* Save initial IRQs. */
527 	for (i = 0; i < sc->pl_num_links; i++)
528 		sc->pl_links[i].l_initial_irq = sc->pl_links[i].l_irq;
529 
530 	/*
531 	 * Try to disable this link.  If successful, set the current IRQ to
532 	 * zero and flags to indicate this link is not routed.  If we can't
533 	 * run _DIS (i.e., the method doesn't exist), assume the initial
534 	 * IRQ was routed by the BIOS.
535 	 */
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 		for (i = 0; i < sc->pl_num_links; i++)
542 			if (PCI_INTERRUPT_VALID(sc->pl_links[i].l_irq))
543 				sc->pl_links[i].l_routed = TRUE;
544 	if (boothowto & AB_VERBOSE) {
545 		printf("%s: Links after disable:\n", sc->pl_name);
546 		acpi_pci_link_dump(sc);
547 	}
548 	ACPI_SERIAL_END(pci_link);
549 	return (0);
550 fail:
551 	ACPI_SERIAL_END(pci_link);
552 	for (i = 0; i < sc->pl_num_links; i++) {
553 		if (sc->pl_links[i].l_irqs != NULL)
554 			free(sc->pl_links[i].l_irqs, M_ACPI);
555 		if (sc->pl_links[i].l_devices != NULL)
556 			free(sc->pl_links[i].l_devices, M_ACPI);
557 	}
558 	free(sc->pl_links, M_ACPI);
559 	return (ENXIO);
560 }
561 
562 static void
563 acpi_pci_link_add_functions(struct acpi_pci_link_softc *sc, struct link *link,
564     int bus, int device, int pin)
565 {
566 	uint32_t value;
567 	uint8_t func, maxfunc, ipin;
568 	pcitag_t tag;
569 
570 	tag = pci_make_tag(acpi_softc->sc_pc, bus, device, 0);
571 	/* See if we have a valid device at function 0. */
572 	value = pci_conf_read(acpi_softc->sc_pc, tag,  PCI_BHLC_REG);
573 	if (PCI_HDRTYPE_TYPE(value) > PCI_HDRTYPE_PCB)
574 		return;
575 	if (PCI_HDRTYPE_MULTIFN(value))
576 		maxfunc = 7;
577 	else
578 		maxfunc = 0;
579 
580 	/* Scan all possible functions at this device. */
581 	for (func = 0; func <= maxfunc; func++) {
582 		tag = pci_make_tag(acpi_softc->sc_pc, bus, device, func);
583 		value = pci_conf_read(acpi_softc->sc_pc, tag, PCI_ID_REG);
584 		if (PCI_VENDOR(value) == 0xffff)
585 			continue;
586 		value = pci_conf_read(acpi_softc->sc_pc, tag,
587 		    PCI_INTERRUPT_REG);
588 		ipin = PCI_INTERRUPT_PIN(value);
589 		/*
590 		 * See if it uses the pin in question.  Note that the passed
591 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
592 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
593 		 */
594 		if (ipin != pin + 1)
595 			continue;
596 
597 		link->l_devices = realloc(link->l_devices,
598 		    sizeof(pcitag_t) * (link->l_dev_count + 1),
599 		    M_ACPI, M_WAITOK);
600 		link->l_devices[link->l_dev_count] = tag;
601 		++link->l_dev_count;
602 	}
603 }
604 
605 static uint8_t
606 acpi_pci_link_search_irq(struct acpi_pci_link_softc *sc, int bus, int device,
607 			 int pin)
608 {
609 	uint32_t value;
610 	uint8_t func, maxfunc, ipin, iline;
611 	pcitag_t tag;
612 
613 	tag = pci_make_tag(acpi_softc->sc_pc, bus, device, 0);
614 	/* See if we have a valid device at function 0. */
615 	value = pci_conf_read(acpi_softc->sc_pc, tag,  PCI_BHLC_REG);
616 	if (PCI_HDRTYPE_TYPE(value) > PCI_HDRTYPE_PCB)
617 		return (PCI_INVALID_IRQ);
618 	if (PCI_HDRTYPE_MULTIFN(value))
619 		maxfunc = 7;
620 	else
621 		maxfunc = 0;
622 
623 	/* Scan all possible functions at this device. */
624 	for (func = 0; func <= maxfunc; func++) {
625 		tag = pci_make_tag(acpi_softc->sc_pc, bus, device, func);
626 		value = pci_conf_read(acpi_softc->sc_pc, tag, PCI_ID_REG);
627 		if (PCI_VENDOR(value) == 0xffff)
628 			continue;
629 		value = pci_conf_read(acpi_softc->sc_pc, tag,
630 		    PCI_INTERRUPT_REG);
631 		ipin = PCI_INTERRUPT_PIN(value);
632 		iline = PCI_INTERRUPT_LINE(value);
633 
634 		/*
635 		 * See if it uses the pin in question.  Note that the passed
636 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
637 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
638 		 */
639 		if (ipin != pin + 1)
640 			continue;
641 		aprint_verbose(
642 		    "%s: ACPI: Found matching pin for %d.%d.INT%c"
643 	            " at func %d: %d\n",
644 			    sc->pl_name, bus, device, pin + 'A', func, iline);
645 		if (PCI_INTERRUPT_VALID(iline))
646 			return (iline);
647 	}
648 	return (PCI_INVALID_IRQ);
649 }
650 
651 /*
652  * Find the link structure that corresponds to the resource index passed in
653  * via 'source_index'.
654  */
655 static struct link *
656 acpi_pci_link_lookup(struct acpi_pci_link_softc *sc, int source_index)
657 {
658 	int i;
659 
660 	for (i = 0; i < sc->pl_num_links; i++)
661 		if (sc->pl_links[i].l_res_index == source_index)
662 			return (&sc->pl_links[i]);
663 	return (NULL);
664 }
665 
666 void
667 acpi_pci_link_add_reference(void *v, int index, int bus, int slot, int pin)
668 {
669 	struct acpi_pci_link_softc *sc = v;
670 	struct link *link;
671 	uint8_t bios_irq;
672 
673 	/* Bump the reference count. */
674 	ACPI_SERIAL_BEGIN(pci_link);
675 	link = acpi_pci_link_lookup(sc, index);
676 	if (link == NULL) {
677 		printf("%s: apparently invalid index %d\n", sc->pl_name, index);
678 		ACPI_SERIAL_END(pci_link);
679 		return;
680 	}
681 	link->l_references++;
682 	acpi_pci_link_add_functions(sc, link, bus, slot, pin);
683 	if (link->l_routed)
684 		pci_link_interrupt_weights[link->l_irq]++;
685 
686 	/*
687 	 * The BIOS only routes interrupts via ISA IRQs using the ATPICs
688 	 * (8259As).  Thus, if this link is routed via an ISA IRQ, go
689 	 * look to see if the BIOS routed an IRQ for this link at the
690 	 * indicated (bus, slot, pin).  If so, we prefer that IRQ for
691 	 * this link and add that IRQ to our list of known-good IRQs.
692 	 * This provides a good work-around for link devices whose _CRS
693 	 * method is either broken or bogus.  We only use the value
694 	 * returned by _CRS if we can't find a valid IRQ via this method
695 	 * in fact.
696 	 *
697 	 * If this link is not routed via an ISA IRQ (because we are using
698 	 * APIC for example), then don't bother looking up the BIOS IRQ
699 	 * as if we find one it won't be valid anyway.
700 	 */
701 	if (!link->l_isa_irq) {
702 		ACPI_SERIAL_END(pci_link);
703 		return;
704 	}
705 
706 	/* Try to find a BIOS IRQ setting from any matching devices. */
707 	bios_irq = acpi_pci_link_search_irq(sc, bus, slot, pin);
708 	if (!PCI_INTERRUPT_VALID(bios_irq)) {
709 		ACPI_SERIAL_END(pci_link);
710 		return;
711 	}
712 
713 	/* Validate the BIOS IRQ. */
714 	if (!link_valid_irq(link, bios_irq)) {
715 		printf("%s: BIOS IRQ %u for %d.%d.INT%c is invalid\n",
716 		    sc->pl_name, bios_irq, (int)bus, slot, pin + 'A');
717 	} else if (!PCI_INTERRUPT_VALID(link->l_bios_irq)) {
718 		link->l_bios_irq = bios_irq;
719 		if (bios_irq < NUM_ISA_INTERRUPTS)
720 			pci_link_bios_isa_irqs |= (1 << bios_irq);
721 		if (bios_irq != link->l_initial_irq &&
722 		    PCI_INTERRUPT_VALID(link->l_initial_irq))
723 			printf(
724 			    "%s: BIOS IRQ %u does not match initial IRQ %u\n",
725 			    sc->pl_name, bios_irq, link->l_initial_irq);
726 	} else if (bios_irq != link->l_bios_irq)
727 		printf(
728 	    "%s: BIOS IRQ %u for %d.%d.INT%c does not match "
729 	    "previous BIOS IRQ %u\n",
730 		    sc->pl_name, bios_irq, (int)bus, slot, pin + 'A',
731 		    link->l_bios_irq);
732 	ACPI_SERIAL_END(pci_link);
733 }
734 
735 static ACPI_STATUS
736 acpi_pci_link_srs_from_crs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
737 {
738 	ACPI_RESOURCE *resource, *end, newres, *resptr;
739 	ACPI_BUFFER crsbuf;
740 	ACPI_STATUS status;
741 	struct link *link;
742 	int i, in_dpf;
743 
744 	/* Fetch the _CRS. */
745 	crsbuf.Pointer = NULL;
746 	crsbuf.Length = ACPI_ALLOCATE_LOCAL_BUFFER;
747 	status = AcpiGetCurrentResources(sc->pl_handle, &crsbuf);
748 	if (ACPI_SUCCESS(status) && crsbuf.Pointer == NULL)
749 		status = AE_NO_MEMORY;
750 	if (ACPI_FAILURE(status)) {
751 		aprint_verbose("%s: Unable to fetch current resources: %s\n",
752 		    sc->pl_name, AcpiFormatException(status));
753 		return (status);
754 	}
755 
756 	/* Fill in IRQ resources via link structures. */
757 	srsbuf->Pointer = NULL;
758 	link = sc->pl_links;
759 	i = 0;
760 	in_dpf = DPF_OUTSIDE;
761 	resource = (ACPI_RESOURCE *)crsbuf.Pointer;
762 	end = (ACPI_RESOURCE *)((char *)crsbuf.Pointer + crsbuf.Length);
763 	for (;;) {
764 		switch (resource->Type) {
765 		case ACPI_RESOURCE_TYPE_START_DEPENDENT:
766 			switch (in_dpf) {
767 			case DPF_OUTSIDE:
768 				/* We've started the first DPF. */
769 				in_dpf = DPF_FIRST;
770 				break;
771 			case DPF_FIRST:
772 				/* We've started the second DPF. */
773 				panic(
774 		"%s: Multiple dependent functions within a current resource",
775 				    __func__);
776 				break;
777 			}
778 			resptr = NULL;
779 			break;
780 		case ACPI_RESOURCE_TYPE_END_DEPENDENT:
781 			/* We are finished with DPF parsing. */
782 			KASSERT(in_dpf != DPF_OUTSIDE);
783 			in_dpf = DPF_OUTSIDE;
784 			resptr = NULL;
785 			break;
786 		case ACPI_RESOURCE_TYPE_IRQ:
787 			newres = link->l_prs_template;
788 			resptr = &newres;
789 			resptr->Data.Irq.InterruptCount = 1;
790 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
791 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS);
792 				resptr->Data.Irq.Interrupts[0] = link->l_irq;
793 				resptr->Data.Irq.Triggering = link->l_trig;
794 				resptr->Data.Irq.Polarity = link->l_pol;
795 			} else
796 				resptr->Data.Irq.Interrupts[0] = 0;
797 			link++;
798 			i++;
799 			break;
800 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
801 			newres = link->l_prs_template;
802 			resptr = &newres;
803 			resptr->Data.ExtendedIrq.InterruptCount = 1;
804 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
805 				resptr->Data.ExtendedIrq.Interrupts[0] =
806 				    link->l_irq;
807 				resptr->Data.ExtendedIrq.Triggering =
808 				    link->l_trig;
809 				resptr->Data.ExtendedIrq.Polarity = link->l_pol;
810 			} else
811 				resptr->Data.ExtendedIrq.Interrupts[0] = 0;
812 			link++;
813 			i++;
814 			break;
815 		default:
816 			resptr = resource;
817 		}
818 		if (resptr != NULL) {
819 			status = acpi_AppendBufferResource(srsbuf, resptr);
820 			if (ACPI_FAILURE(status)) {
821 				printf("%s: Unable to build resources: %s\n",
822 				    sc->pl_name, AcpiFormatException(status));
823 				if (srsbuf->Pointer != NULL)
824 					ACPI_FREE(srsbuf->Pointer);
825 				ACPI_FREE(crsbuf.Pointer);
826 				return (status);
827 			}
828 		}
829 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
830 			break;
831 		resource = ACPI_NEXT_RESOURCE(resource);
832 		if (resource >= end)
833 			break;
834 	}
835 	ACPI_FREE(crsbuf.Pointer);
836 	return (AE_OK);
837 }
838 
839 static ACPI_STATUS
840 acpi_pci_link_srs_from_links(struct acpi_pci_link_softc *sc,
841     ACPI_BUFFER *srsbuf)
842 {
843 	ACPI_RESOURCE newres;
844 	ACPI_STATUS status;
845 	struct link *link;
846 	int i;
847 
848 	/* Start off with an empty buffer. */
849 	srsbuf->Pointer = NULL;
850 	link = sc->pl_links;
851 	for (i = 0; i < sc->pl_num_links; i++) {
852 
853 		/* Add a new IRQ resource from each link. */
854 		link = &sc->pl_links[i];
855 		newres = link->l_prs_template;
856 		if (newres.Type == ACPI_RESOURCE_TYPE_IRQ) {
857 
858 			/* Build an IRQ resource. */
859 			newres.Data.Irq.InterruptCount = 1;
860 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
861 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS);
862 				newres.Data.Irq.Interrupts[0] = link->l_irq;
863 				newres.Data.Irq.Triggering = link->l_trig;
864 				newres.Data.Irq.Polarity = link->l_pol;
865 			} else
866 				newres.Data.Irq.Interrupts[0] = 0;
867 		} else {
868 
869 			/* Build an ExtIRQ resuorce. */
870 			newres.Data.ExtendedIrq.InterruptCount = 1;
871 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
872 				newres.Data.ExtendedIrq.Interrupts[0] =
873 				    link->l_irq;
874 				newres.Data.ExtendedIrq.Triggering =
875 				    link->l_trig;
876 				newres.Data.ExtendedIrq.Polarity =
877 				    link->l_pol;
878 			} else {
879 				newres.Data.ExtendedIrq.Interrupts[0] = 0;
880 			}
881 		}
882 
883 		/* Add the new resource to the end of the _SRS buffer. */
884 		status = acpi_AppendBufferResource(srsbuf, &newres);
885 		if (ACPI_FAILURE(status)) {
886 			printf("%s: Unable to build resources: %s\n",
887 			    sc->pl_name, AcpiFormatException(status));
888 			if (srsbuf->Pointer != NULL)
889 				ACPI_FREE(srsbuf->Pointer);
890 			return (status);
891 		}
892 	}
893 	return (AE_OK);
894 }
895 
896 static ACPI_STATUS
897 acpi_pci_link_srs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
898 {
899 	ACPI_STATUS status;
900 
901 	if (sc->pl_crs_bad)
902 		status = acpi_pci_link_srs_from_links(sc, srsbuf);
903 	else
904 		status = acpi_pci_link_srs_from_crs(sc, srsbuf);
905 
906 	/* Write out new resources via _SRS. */
907 	return AcpiSetCurrentResources(sc->pl_handle, srsbuf);
908 }
909 
910 static ACPI_STATUS
911 acpi_pci_link_route_irqs(struct acpi_pci_link_softc *sc, int *irq, int *pol,
912 			 int *trig)
913 {
914 	ACPI_RESOURCE *resource, *end;
915 	ACPI_BUFFER srsbuf;
916 	ACPI_STATUS status;
917 	struct link *link;
918 	int i, is_ext = 0;
919 
920 	status = acpi_pci_link_srs(sc, &srsbuf);
921 	if (ACPI_FAILURE(status)) {
922 		printf("%s: _SRS failed: %s\n",
923 		    sc->pl_name, AcpiFormatException(status));
924 		return (status);
925 	}
926 	/*
927 	 * Perform acpi_config_intr() on each IRQ resource if it was just
928 	 * routed for the first time.
929 	 */
930 	link = sc->pl_links;
931 	i = 0;
932 	resource = (ACPI_RESOURCE *)srsbuf.Pointer;
933 	end = (ACPI_RESOURCE *)((char *)srsbuf.Pointer + srsbuf.Length);
934 	for (;;) {
935 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
936 			break;
937 		switch (resource->Type) {
938 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
939 			is_ext = 1;
940 			/* FALLTHROUGH */
941 		case ACPI_RESOURCE_TYPE_IRQ:
942 			/*
943 			 * Only configure the interrupt and update the
944 			 * weights if this link has a valid IRQ and was
945 			 * previously unrouted.
946 			 */
947 			if (!link->l_routed &&
948 			    PCI_INTERRUPT_VALID(link->l_irq)) {
949 				*trig = is_ext ?
950 				    resource->Data.ExtendedIrq.Triggering :
951 				    resource->Data.Irq.Triggering;
952 				*pol = is_ext ?
953 				    resource->Data.ExtendedIrq.Polarity :
954 				    resource->Data.Irq.Polarity;
955 				*irq = is_ext ?
956 				    resource->Data.ExtendedIrq.Interrupts[0] :
957 				    resource->Data.Irq.Interrupts[0];
958 				link->l_routed = TRUE;
959 				pci_link_interrupt_weights[link->l_irq] +=
960 				    link->l_references;
961 			}
962 			link++;
963 			i++;
964 			break;
965 		}
966 		resource = ACPI_NEXT_RESOURCE(resource);
967 		if (resource >= end)
968 			break;
969 	}
970 	ACPI_FREE(srsbuf.Pointer);
971 	return (AE_OK);
972 }
973 
974 /*
975  * Pick an IRQ to use for this unrouted link.
976  */
977 static uint8_t
978 acpi_pci_link_choose_irq(struct acpi_pci_link_softc *sc, struct link *link)
979 {
980 	u_int8_t best_irq, pos_irq;
981 	int best_weight, pos_weight, i;
982 
983 	KASSERT(!link->l_routed);
984 	KASSERT(!PCI_INTERRUPT_VALID(link->l_irq));
985 
986 	/*
987 	 * If we have a valid BIOS IRQ, use that.  We trust what the BIOS
988 	 * says it routed over what _CRS says the link thinks is routed.
989 	 */
990 	if (PCI_INTERRUPT_VALID(link->l_bios_irq))
991 		return (link->l_bios_irq);
992 
993 	/*
994 	 * If we don't have a BIOS IRQ but do have a valid IRQ from _CRS,
995 	 * then use that.
996 	 */
997 	if (PCI_INTERRUPT_VALID(link->l_initial_irq))
998 		return (link->l_initial_irq);
999 
1000 	/*
1001 	 * Ok, we have no useful hints, so we have to pick from the
1002 	 * possible IRQs.  For ISA IRQs we only use interrupts that
1003 	 * have already been used by the BIOS.
1004 	 */
1005 	best_irq = PCI_INVALID_IRQ;
1006 	best_weight = INT_MAX;
1007 	for (i = 0; i < link->l_num_irqs; i++) {
1008 		pos_irq = link->l_irqs[i];
1009 		if (pos_irq < NUM_ISA_INTERRUPTS &&
1010 		    (pci_link_bios_isa_irqs & 1 << pos_irq) == 0)
1011 			continue;
1012 		pos_weight = pci_link_interrupt_weights[pos_irq];
1013 		if (pos_weight < best_weight) {
1014 			best_weight = pos_weight;
1015 			best_irq = pos_irq;
1016 		}
1017 	}
1018 
1019 	/*
1020 	 * If this is an ISA IRQ, try using the SCI if it is also an ISA
1021 	 * interrupt as a fallback.
1022 	 */
1023 	if (link->l_isa_irq && !PCI_INTERRUPT_VALID(best_irq)) {
1024 		pos_irq = AcpiGbl_FADT.SciInterrupt;
1025 		pos_weight = pci_link_interrupt_weights[pos_irq];
1026 		if (pos_weight < best_weight) {
1027 			best_weight = pos_weight;
1028 			best_irq = pos_irq;
1029 		}
1030 	}
1031 
1032 	if (PCI_INTERRUPT_VALID(best_irq)) {
1033 		aprint_verbose("%s: Picked IRQ %u with weight %d\n",
1034 		    sc->pl_name, best_irq, best_weight);
1035 	} else
1036 		printf("%s: Unable to choose an IRQ\n", sc->pl_name);
1037 	return (best_irq);
1038 }
1039 
1040 int
1041 acpi_pci_link_route_interrupt(void *v, int index, int *irq, int *pol, int *trig)
1042 {
1043 	struct acpi_pci_link_softc *sc = v;
1044 	struct link *link;
1045 	int i;
1046 	pcireg_t reg;
1047 
1048 	ACPI_SERIAL_BEGIN(pci_link);
1049 	link = acpi_pci_link_lookup(sc, index);
1050 	if (link == NULL)
1051 		panic("%s: apparently invalid index %d", __func__, index);
1052 
1053 	/*
1054 	 * If this link device is already routed to an interrupt, just return
1055 	 * the interrupt it is routed to.
1056 	 */
1057 	if (link->l_routed) {
1058 		KASSERT(PCI_INTERRUPT_VALID(link->l_irq));
1059 		ACPI_SERIAL_END(pci_link);
1060 		*irq = link->l_irq;
1061 		*pol = link->l_pol;
1062 		*trig = link->l_trig;
1063 		return (link->l_irq);
1064 	}
1065 
1066 	/* Choose an IRQ if we need one. */
1067 	if (PCI_INTERRUPT_VALID(link->l_irq)) {
1068 		*irq = link->l_irq;
1069 		*pol = link->l_pol;
1070 		*trig = link->l_trig;
1071 		goto done;
1072 	}
1073 
1074 	link->l_irq = acpi_pci_link_choose_irq(sc, link);
1075 
1076 	/*
1077 	 * Try to route the interrupt we picked.  If it fails, then
1078 	 * assume the interrupt is not routed.
1079 	 */
1080 	if (!PCI_INTERRUPT_VALID(link->l_irq))
1081 		goto done;
1082 
1083 	acpi_pci_link_route_irqs(sc, irq, pol, trig);
1084 	if (!link->l_routed) {
1085 		link->l_irq = PCI_INVALID_IRQ;
1086 		goto done;
1087 	}
1088 
1089 	link->l_pol = *pol;
1090 	link->l_trig = *trig;
1091 	for (i = 0; i < link->l_dev_count; ++i) {
1092 		reg = pci_conf_read(acpi_softc->sc_pc, link->l_devices[i],
1093 		    PCI_INTERRUPT_REG);
1094 		reg &= ~(PCI_INTERRUPT_LINE_MASK << PCI_INTERRUPT_LINE_SHIFT);
1095 		reg |= link->l_irq << PCI_INTERRUPT_LINE_SHIFT;
1096 		pci_conf_write(acpi_softc->sc_pc, link->l_devices[i],
1097 		    PCI_INTERRUPT_REG, reg);
1098 	}
1099 
1100 done:
1101 	ACPI_SERIAL_END(pci_link);
1102 
1103 	return (link->l_irq);
1104 }
1105 
1106 /*
1107  * This is gross, but we abuse the identify routine to perform one-time
1108  * SYSINIT() style initialization for the driver.
1109  */
1110 static void
1111 acpi_pci_link_init(struct acpi_pci_link_softc *sc)
1112 {
1113 	ACPI_BUFFER buf;
1114 
1115 	/*
1116 	 * If the SCI is an ISA IRQ, add it to the bitmask of known good
1117 	 * ISA IRQs.
1118 	 *
1119 	 * XXX: If we are using the APIC, the SCI might have been
1120 	 * rerouted to an APIC pin in which case this is invalid.  However,
1121 	 * if we are using the APIC, we also shouldn't be having any PCI
1122 	 * interrupts routed via ISA IRQs, so this is probably ok.
1123 	 */
1124 	if (AcpiGbl_FADT.SciInterrupt < NUM_ISA_INTERRUPTS)
1125 		pci_link_bios_isa_irqs |= (1 << AcpiGbl_FADT.SciInterrupt);
1126 
1127 	buf.Length = sizeof (sc->pl_name);
1128 	buf.Pointer = sc->pl_name;
1129 
1130 	if (ACPI_FAILURE(AcpiGetName(sc->pl_handle, ACPI_SINGLE_NAME, &buf)))
1131 		snprintf(sc->pl_name, sizeof (sc->pl_name), "%s",
1132 		    "ACPI link device");
1133 
1134 	acpi_pci_link_attach(sc);
1135 }
1136 
1137 void *
1138 acpi_pci_link_devbyhandle(ACPI_HANDLE handle)
1139 {
1140 	struct acpi_pci_link_softc *sc;
1141 
1142 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
1143 		if (sc->pl_handle == handle)
1144 			return sc;
1145 	}
1146 
1147 	sc = malloc(sizeof (*sc), M_ACPI, M_NOWAIT | M_ZERO);
1148 	if (sc == NULL)
1149 		return NULL;
1150 
1151 	sc->pl_handle = handle;
1152 
1153 	acpi_pci_link_init(sc);
1154 
1155 	TAILQ_INSERT_TAIL(&acpi_pci_linkdevs, sc, pl_list);
1156 
1157 	return (void *)sc;
1158 }
1159 
1160 void
1161 acpi_pci_link_resume(void)
1162 {
1163 	struct acpi_pci_link_softc *sc;
1164 	ACPI_BUFFER srsbuf;
1165 
1166 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
1167 		ACPI_SERIAL_BEGIN(pci_link);
1168 		if (ACPI_SUCCESS(acpi_pci_link_srs(sc, &srsbuf)))
1169 			ACPI_FREE(srsbuf.Pointer);
1170 		ACPI_SERIAL_END(pci_link);
1171 	}
1172 }
1173 
1174 ACPI_HANDLE
1175 acpi_pci_link_handle(void *v)
1176 {
1177 	struct acpi_pci_link_softc *sc = v;
1178 
1179 	return sc->pl_handle;
1180 }
1181 
1182 char *
1183 acpi_pci_link_name(void *v)
1184 {
1185 	struct acpi_pci_link_softc *sc = v;
1186 
1187 	return sc->pl_name;
1188 }
1189 
1190 
1191 /*
1192  * Append an ACPI_RESOURCE to an ACPI_BUFFER.
1193  *
1194  * Given a pointer to an ACPI_RESOURCE structure, expand the ACPI_BUFFER
1195  * provided to contain it.  If the ACPI_BUFFER is empty, allocate a sensible
1196  * backing block.  If the ACPI_RESOURCE is NULL, return an empty set of
1197  * resources.
1198  */
1199 #define ACPI_INITIAL_RESOURCE_BUFFER_SIZE	512
1200 
1201 static ACPI_STATUS
1202 acpi_AppendBufferResource(ACPI_BUFFER *buf, ACPI_RESOURCE *res)
1203 {
1204 	ACPI_RESOURCE	*rp;
1205 	void		*newp;
1206 
1207 	/* Initialise the buffer if necessary. */
1208 	if (buf->Pointer == NULL) {
1209 	buf->Length = ACPI_INITIAL_RESOURCE_BUFFER_SIZE;
1210 	if ((buf->Pointer = ACPI_ALLOCATE(buf->Length)) == NULL)
1211 		return (AE_NO_MEMORY);
1212 	rp = (ACPI_RESOURCE *)buf->Pointer;
1213 	rp->Type =  ACPI_RESOURCE_TYPE_END_TAG;
1214 	rp->Length = 0;
1215 	}
1216 
1217 	if (res == NULL)
1218 		return (AE_OK);
1219 
1220 	/*
1221 	 * Scan the current buffer looking for the terminator.
1222 	 * This will either find the terminator or hit the end
1223 	 * of the buffer and return an error.
1224 	 */
1225 	rp = (ACPI_RESOURCE *)buf->Pointer;
1226 	for (;;) {
1227 		/* Range check, don't go outside the buffer */
1228 		if (rp >= (ACPI_RESOURCE *)((u_int8_t *)buf->Pointer +
1229 		    buf->Length))
1230 			return (AE_BAD_PARAMETER);
1231 		if (rp->Type ==  ACPI_RESOURCE_TYPE_END_TAG || rp->Length == 0)
1232 			break;
1233 		rp = ACPI_NEXT_RESOURCE(rp);
1234 	}
1235 
1236 	/*
1237 	 * Check the size of the buffer and expand if required.
1238 	 *
1239 	 * Required size is:
1240 	 *	size of existing resources before terminator +
1241 	 *	size of new resource and header +
1242 	 * 	size of terminator.
1243 	 *
1244 	 * Note that this loop should really only run once, unless
1245 	 * for some reason we are stuffing a *really* huge resource.
1246 	 */
1247 	while ((((u_int8_t *)rp - (u_int8_t *)buf->Pointer) +
1248 	    res->Length + ACPI_RS_SIZE_NO_DATA +
1249 	    ACPI_RS_SIZE_MIN) >= buf->Length) {
1250 		if ((newp = ACPI_ALLOCATE(buf->Length * 2)) == NULL)
1251 			return (AE_NO_MEMORY);
1252 		memcpy(newp, buf->Pointer, buf->Length);
1253 		rp = (ACPI_RESOURCE *)((u_int8_t *)newp +
1254 		   ((u_int8_t *)rp - (u_int8_t *)buf->Pointer));
1255 		ACPI_FREE(buf->Pointer);
1256 		buf->Pointer = newp;
1257 		buf->Length += buf->Length;
1258 	}
1259 
1260 	/* Insert the new resource. */
1261 	memcpy(rp, res, res->Length + ACPI_RS_SIZE_NO_DATA);
1262 
1263 	/* And add the terminator. */
1264 	rp = ACPI_NEXT_RESOURCE(rp);
1265 	rp->Type =  ACPI_RESOURCE_TYPE_END_TAG;
1266 	rp->Length = 0;
1267 
1268 	return (AE_OK);
1269 }
1270