xref: /netbsd-src/sys/dev/acpi/acpi_pci_link.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: acpi_pci_link.c,v 1.18 2010/04/23 15:52:26 jruoho 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 1.18 2010/04/23 15:52:26 jruoho 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 0	/* XXX causes spontaneaous resets on some systems. Disabled for now. */
537 	if (ACPI_SUCCESS(AcpiEvaluateObject(sc->pl_handle, "_DIS", NULL,
538 	    NULL)))
539 		for (i = 0; i < sc->pl_num_links; i++)
540 			sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
541 	else
542 #endif
543 		for (i = 0; i < sc->pl_num_links; i++)
544 			if (PCI_INTERRUPT_VALID(sc->pl_links[i].l_irq))
545 				sc->pl_links[i].l_routed = TRUE;
546 	if (boothowto & AB_VERBOSE) {
547 		printf("%s: Links after disable:\n", sc->pl_name);
548 		acpi_pci_link_dump(sc);
549 	}
550 	ACPI_SERIAL_END(pci_link);
551 	return (0);
552 fail:
553 	ACPI_SERIAL_END(pci_link);
554 	for (i = 0; i < sc->pl_num_links; i++) {
555 		if (sc->pl_links[i].l_irqs != NULL)
556 			free(sc->pl_links[i].l_irqs, M_ACPI);
557 		if (sc->pl_links[i].l_devices != NULL)
558 			free(sc->pl_links[i].l_devices, M_ACPI);
559 	}
560 	free(sc->pl_links, M_ACPI);
561 	return (ENXIO);
562 }
563 
564 static void
565 acpi_pci_link_add_functions(struct acpi_pci_link_softc *sc, struct link *link,
566     int bus, int device, int pin)
567 {
568 	uint32_t value;
569 	uint8_t func, maxfunc, ipin;
570 	pcitag_t tag;
571 
572 	tag = pci_make_tag(acpi_softc->sc_pc, bus, device, 0);
573 	/* See if we have a valid device at function 0. */
574 	value = pci_conf_read(acpi_softc->sc_pc, tag,  PCI_BHLC_REG);
575 	if (PCI_HDRTYPE_TYPE(value) > PCI_HDRTYPE_PCB)
576 		return;
577 	if (PCI_HDRTYPE_MULTIFN(value))
578 		maxfunc = 7;
579 	else
580 		maxfunc = 0;
581 
582 	/* Scan all possible functions at this device. */
583 	for (func = 0; func <= maxfunc; func++) {
584 		tag = pci_make_tag(acpi_softc->sc_pc, bus, device, func);
585 		value = pci_conf_read(acpi_softc->sc_pc, tag, PCI_ID_REG);
586 		if (PCI_VENDOR(value) == 0xffff)
587 			continue;
588 		value = pci_conf_read(acpi_softc->sc_pc, tag,
589 		    PCI_INTERRUPT_REG);
590 		ipin = PCI_INTERRUPT_PIN(value);
591 		/*
592 		 * See if it uses the pin in question.  Note that the passed
593 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
594 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
595 		 */
596 		if (ipin != pin + 1)
597 			continue;
598 
599 		link->l_devices = realloc(link->l_devices,
600 		    sizeof(pcitag_t) * (link->l_dev_count + 1),
601 		    M_ACPI, M_WAITOK);
602 		link->l_devices[link->l_dev_count] = tag;
603 		++link->l_dev_count;
604 	}
605 }
606 
607 static uint8_t
608 acpi_pci_link_search_irq(struct acpi_pci_link_softc *sc, int bus, int device,
609 			 int pin)
610 {
611 	uint32_t value;
612 	uint8_t func, maxfunc, ipin, iline;
613 	pcitag_t tag;
614 
615 	tag = pci_make_tag(acpi_softc->sc_pc, bus, device, 0);
616 	/* See if we have a valid device at function 0. */
617 	value = pci_conf_read(acpi_softc->sc_pc, tag,  PCI_BHLC_REG);
618 	if (PCI_HDRTYPE_TYPE(value) > PCI_HDRTYPE_PCB)
619 		return (PCI_INVALID_IRQ);
620 	if (PCI_HDRTYPE_MULTIFN(value))
621 		maxfunc = 7;
622 	else
623 		maxfunc = 0;
624 
625 	/* Scan all possible functions at this device. */
626 	for (func = 0; func <= maxfunc; func++) {
627 		tag = pci_make_tag(acpi_softc->sc_pc, bus, device, func);
628 		value = pci_conf_read(acpi_softc->sc_pc, tag, PCI_ID_REG);
629 		if (PCI_VENDOR(value) == 0xffff)
630 			continue;
631 		value = pci_conf_read(acpi_softc->sc_pc, tag,
632 		    PCI_INTERRUPT_REG);
633 		ipin = PCI_INTERRUPT_PIN(value);
634 		iline = PCI_INTERRUPT_LINE(value);
635 
636 		/*
637 		 * See if it uses the pin in question.  Note that the passed
638 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
639 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
640 		 */
641 		if (ipin != pin + 1)
642 			continue;
643 		aprint_verbose(
644 		    "%s: ACPI: Found matching pin for %d.%d.INT%c"
645 	            " at func %d: %d\n",
646 			    sc->pl_name, bus, device, pin + 'A', func, iline);
647 		if (PCI_INTERRUPT_VALID(iline))
648 			return (iline);
649 	}
650 	return (PCI_INVALID_IRQ);
651 }
652 
653 /*
654  * Find the link structure that corresponds to the resource index passed in
655  * via 'source_index'.
656  */
657 static struct link *
658 acpi_pci_link_lookup(struct acpi_pci_link_softc *sc, int source_index)
659 {
660 	int i;
661 
662 	for (i = 0; i < sc->pl_num_links; i++)
663 		if (sc->pl_links[i].l_res_index == source_index)
664 			return (&sc->pl_links[i]);
665 	return (NULL);
666 }
667 
668 void
669 acpi_pci_link_add_reference(void *v, int index, int bus, int slot, int pin)
670 {
671 	struct acpi_pci_link_softc *sc = v;
672 	struct link *link;
673 	uint8_t bios_irq;
674 
675 	/* Bump the reference count. */
676 	ACPI_SERIAL_BEGIN(pci_link);
677 	link = acpi_pci_link_lookup(sc, index);
678 	if (link == NULL) {
679 		printf("%s: apparently invalid index %d\n", sc->pl_name, index);
680 		ACPI_SERIAL_END(pci_link);
681 		return;
682 	}
683 	link->l_references++;
684 	acpi_pci_link_add_functions(sc, link, bus, slot, pin);
685 	if (link->l_routed)
686 		pci_link_interrupt_weights[link->l_irq]++;
687 
688 	/*
689 	 * The BIOS only routes interrupts via ISA IRQs using the ATPICs
690 	 * (8259As).  Thus, if this link is routed via an ISA IRQ, go
691 	 * look to see if the BIOS routed an IRQ for this link at the
692 	 * indicated (bus, slot, pin).  If so, we prefer that IRQ for
693 	 * this link and add that IRQ to our list of known-good IRQs.
694 	 * This provides a good work-around for link devices whose _CRS
695 	 * method is either broken or bogus.  We only use the value
696 	 * returned by _CRS if we can't find a valid IRQ via this method
697 	 * in fact.
698 	 *
699 	 * If this link is not routed via an ISA IRQ (because we are using
700 	 * APIC for example), then don't bother looking up the BIOS IRQ
701 	 * as if we find one it won't be valid anyway.
702 	 */
703 	if (!link->l_isa_irq) {
704 		ACPI_SERIAL_END(pci_link);
705 		return;
706 	}
707 
708 	/* Try to find a BIOS IRQ setting from any matching devices. */
709 	bios_irq = acpi_pci_link_search_irq(sc, bus, slot, pin);
710 	if (!PCI_INTERRUPT_VALID(bios_irq)) {
711 		ACPI_SERIAL_END(pci_link);
712 		return;
713 	}
714 
715 	/* Validate the BIOS IRQ. */
716 	if (!link_valid_irq(link, bios_irq)) {
717 		printf("%s: BIOS IRQ %u for %d.%d.INT%c is invalid\n",
718 		    sc->pl_name, bios_irq, (int)bus, slot, pin + 'A');
719 	} else if (!PCI_INTERRUPT_VALID(link->l_bios_irq)) {
720 		link->l_bios_irq = bios_irq;
721 		if (bios_irq < NUM_ISA_INTERRUPTS)
722 			pci_link_bios_isa_irqs |= (1 << bios_irq);
723 		if (bios_irq != link->l_initial_irq &&
724 		    PCI_INTERRUPT_VALID(link->l_initial_irq))
725 			printf(
726 			    "%s: BIOS IRQ %u does not match initial IRQ %u\n",
727 			    sc->pl_name, bios_irq, link->l_initial_irq);
728 	} else if (bios_irq != link->l_bios_irq)
729 		printf(
730 	    "%s: BIOS IRQ %u for %d.%d.INT%c does not match "
731 	    "previous BIOS IRQ %u\n",
732 		    sc->pl_name, bios_irq, (int)bus, slot, pin + 'A',
733 		    link->l_bios_irq);
734 	ACPI_SERIAL_END(pci_link);
735 }
736 
737 static ACPI_STATUS
738 acpi_pci_link_srs_from_crs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
739 {
740 	ACPI_RESOURCE *resource, *end, newres, *resptr;
741 	ACPI_BUFFER crsbuf;
742 	ACPI_STATUS status;
743 	struct link *link;
744 	int i, in_dpf;
745 
746 	/* Fetch the _CRS. */
747 	crsbuf.Pointer = NULL;
748 	crsbuf.Length = ACPI_ALLOCATE_LOCAL_BUFFER;
749 	status = AcpiGetCurrentResources(sc->pl_handle, &crsbuf);
750 	if (ACPI_SUCCESS(status) && crsbuf.Pointer == NULL)
751 		status = AE_NO_MEMORY;
752 	if (ACPI_FAILURE(status)) {
753 		aprint_verbose("%s: Unable to fetch current resources: %s\n",
754 		    sc->pl_name, AcpiFormatException(status));
755 		return (status);
756 	}
757 
758 	/* Fill in IRQ resources via link structures. */
759 	srsbuf->Pointer = NULL;
760 	link = sc->pl_links;
761 	i = 0;
762 	in_dpf = DPF_OUTSIDE;
763 	resource = (ACPI_RESOURCE *)crsbuf.Pointer;
764 	end = (ACPI_RESOURCE *)((char *)crsbuf.Pointer + crsbuf.Length);
765 	for (;;) {
766 		switch (resource->Type) {
767 		case ACPI_RESOURCE_TYPE_START_DEPENDENT:
768 			switch (in_dpf) {
769 			case DPF_OUTSIDE:
770 				/* We've started the first DPF. */
771 				in_dpf = DPF_FIRST;
772 				break;
773 			case DPF_FIRST:
774 				/* We've started the second DPF. */
775 				panic(
776 		"%s: Multiple dependent functions within a current resource",
777 				    __func__);
778 				break;
779 			}
780 			resptr = NULL;
781 			break;
782 		case ACPI_RESOURCE_TYPE_END_DEPENDENT:
783 			/* We are finished with DPF parsing. */
784 			KASSERT(in_dpf != DPF_OUTSIDE);
785 			in_dpf = DPF_OUTSIDE;
786 			resptr = NULL;
787 			break;
788 		case ACPI_RESOURCE_TYPE_IRQ:
789 			newres = link->l_prs_template;
790 			resptr = &newres;
791 			resptr->Data.Irq.InterruptCount = 1;
792 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
793 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS);
794 				resptr->Data.Irq.Interrupts[0] = link->l_irq;
795 				resptr->Data.Irq.Triggering = link->l_trig;
796 				resptr->Data.Irq.Polarity = link->l_pol;
797 			} else
798 				resptr->Data.Irq.Interrupts[0] = 0;
799 			link++;
800 			i++;
801 			break;
802 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
803 			newres = link->l_prs_template;
804 			resptr = &newres;
805 			resptr->Data.ExtendedIrq.InterruptCount = 1;
806 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
807 				resptr->Data.ExtendedIrq.Interrupts[0] =
808 				    link->l_irq;
809 				resptr->Data.ExtendedIrq.Triggering =
810 				    link->l_trig;
811 				resptr->Data.ExtendedIrq.Polarity = link->l_pol;
812 			} else
813 				resptr->Data.ExtendedIrq.Interrupts[0] = 0;
814 			link++;
815 			i++;
816 			break;
817 		default:
818 			resptr = resource;
819 		}
820 		if (resptr != NULL) {
821 			status = acpi_AppendBufferResource(srsbuf, resptr);
822 			if (ACPI_FAILURE(status)) {
823 				printf("%s: Unable to build resources: %s\n",
824 				    sc->pl_name, AcpiFormatException(status));
825 				if (srsbuf->Pointer != NULL)
826 					ACPI_FREE(srsbuf->Pointer);
827 				ACPI_FREE(crsbuf.Pointer);
828 				return (status);
829 			}
830 		}
831 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
832 			break;
833 		resource = ACPI_NEXT_RESOURCE(resource);
834 		if (resource >= end)
835 			break;
836 	}
837 	ACPI_FREE(crsbuf.Pointer);
838 	return (AE_OK);
839 }
840 
841 static ACPI_STATUS
842 acpi_pci_link_srs_from_links(struct acpi_pci_link_softc *sc,
843     ACPI_BUFFER *srsbuf)
844 {
845 	ACPI_RESOURCE newres;
846 	ACPI_STATUS status;
847 	struct link *link;
848 	int i;
849 
850 	/* Start off with an empty buffer. */
851 	srsbuf->Pointer = NULL;
852 	link = sc->pl_links;
853 	for (i = 0; i < sc->pl_num_links; i++) {
854 
855 		/* Add a new IRQ resource from each link. */
856 		link = &sc->pl_links[i];
857 		newres = link->l_prs_template;
858 		if (newres.Type == ACPI_RESOURCE_TYPE_IRQ) {
859 
860 			/* Build an IRQ resource. */
861 			newres.Data.Irq.InterruptCount = 1;
862 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
863 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS);
864 				newres.Data.Irq.Interrupts[0] = link->l_irq;
865 				newres.Data.Irq.Triggering = link->l_trig;
866 				newres.Data.Irq.Polarity = link->l_pol;
867 			} else
868 				newres.Data.Irq.Interrupts[0] = 0;
869 		} else {
870 
871 			/* Build an ExtIRQ resuorce. */
872 			newres.Data.ExtendedIrq.InterruptCount = 1;
873 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
874 				newres.Data.ExtendedIrq.Interrupts[0] =
875 				    link->l_irq;
876 				newres.Data.ExtendedIrq.Triggering =
877 				    link->l_trig;
878 				newres.Data.ExtendedIrq.Polarity =
879 				    link->l_pol;
880 			} else {
881 				newres.Data.ExtendedIrq.Interrupts[0] = 0;
882 			}
883 		}
884 
885 		/* Add the new resource to the end of the _SRS buffer. */
886 		status = acpi_AppendBufferResource(srsbuf, &newres);
887 		if (ACPI_FAILURE(status)) {
888 			printf("%s: Unable to build resources: %s\n",
889 			    sc->pl_name, AcpiFormatException(status));
890 			if (srsbuf->Pointer != NULL)
891 				ACPI_FREE(srsbuf->Pointer);
892 			return (status);
893 		}
894 	}
895 	return (AE_OK);
896 }
897 
898 static ACPI_STATUS
899 acpi_pci_link_srs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
900 {
901 	ACPI_STATUS status;
902 
903 	if (sc->pl_crs_bad)
904 		status = acpi_pci_link_srs_from_links(sc, srsbuf);
905 	else
906 		status = acpi_pci_link_srs_from_crs(sc, srsbuf);
907 
908 	/* Write out new resources via _SRS. */
909 	return AcpiSetCurrentResources(sc->pl_handle, srsbuf);
910 }
911 
912 static ACPI_STATUS
913 acpi_pci_link_route_irqs(struct acpi_pci_link_softc *sc, int *irq, int *pol,
914 			 int *trig)
915 {
916 	ACPI_RESOURCE *resource, *end;
917 	ACPI_BUFFER srsbuf;
918 	ACPI_STATUS status;
919 	struct link *link;
920 	int i, is_ext = 0;
921 
922 	status = acpi_pci_link_srs(sc, &srsbuf);
923 	if (ACPI_FAILURE(status)) {
924 		printf("%s: _SRS failed: %s\n",
925 		    sc->pl_name, AcpiFormatException(status));
926 		return (status);
927 	}
928 	/*
929 	 * Perform acpi_config_intr() on each IRQ resource if it was just
930 	 * routed for the first time.
931 	 */
932 	link = sc->pl_links;
933 	i = 0;
934 	resource = (ACPI_RESOURCE *)srsbuf.Pointer;
935 	end = (ACPI_RESOURCE *)((char *)srsbuf.Pointer + srsbuf.Length);
936 	for (;;) {
937 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
938 			break;
939 		switch (resource->Type) {
940 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
941 			is_ext = 1;
942 			/* FALLTHROUGH */
943 		case ACPI_RESOURCE_TYPE_IRQ:
944 			/*
945 			 * Only configure the interrupt and update the
946 			 * weights if this link has a valid IRQ and was
947 			 * previously unrouted.
948 			 */
949 			if (!link->l_routed &&
950 			    PCI_INTERRUPT_VALID(link->l_irq)) {
951 				*trig = is_ext ?
952 				    resource->Data.ExtendedIrq.Triggering :
953 				    resource->Data.Irq.Triggering;
954 				*pol = is_ext ?
955 				    resource->Data.ExtendedIrq.Polarity :
956 				    resource->Data.Irq.Polarity;
957 				*irq = is_ext ?
958 				    resource->Data.ExtendedIrq.Interrupts[0] :
959 				    resource->Data.Irq.Interrupts[0];
960 				link->l_routed = TRUE;
961 				pci_link_interrupt_weights[link->l_irq] +=
962 				    link->l_references;
963 			}
964 			link++;
965 			i++;
966 			break;
967 		}
968 		resource = ACPI_NEXT_RESOURCE(resource);
969 		if (resource >= end)
970 			break;
971 	}
972 	ACPI_FREE(srsbuf.Pointer);
973 	return (AE_OK);
974 }
975 
976 /*
977  * Pick an IRQ to use for this unrouted link.
978  */
979 static uint8_t
980 acpi_pci_link_choose_irq(struct acpi_pci_link_softc *sc, struct link *link)
981 {
982 	u_int8_t best_irq, pos_irq;
983 	int best_weight, pos_weight, i;
984 
985 	KASSERT(!link->l_routed);
986 	KASSERT(!PCI_INTERRUPT_VALID(link->l_irq));
987 
988 	/*
989 	 * If we have a valid BIOS IRQ, use that.  We trust what the BIOS
990 	 * says it routed over what _CRS says the link thinks is routed.
991 	 */
992 	if (PCI_INTERRUPT_VALID(link->l_bios_irq))
993 		return (link->l_bios_irq);
994 
995 	/*
996 	 * If we don't have a BIOS IRQ but do have a valid IRQ from _CRS,
997 	 * then use that.
998 	 */
999 	if (PCI_INTERRUPT_VALID(link->l_initial_irq))
1000 		return (link->l_initial_irq);
1001 
1002 	/*
1003 	 * Ok, we have no useful hints, so we have to pick from the
1004 	 * possible IRQs.  For ISA IRQs we only use interrupts that
1005 	 * have already been used by the BIOS.
1006 	 */
1007 	best_irq = PCI_INVALID_IRQ;
1008 	best_weight = INT_MAX;
1009 	for (i = 0; i < link->l_num_irqs; i++) {
1010 		pos_irq = link->l_irqs[i];
1011 		if (pos_irq < NUM_ISA_INTERRUPTS &&
1012 		    (pci_link_bios_isa_irqs & 1 << pos_irq) == 0)
1013 			continue;
1014 		pos_weight = pci_link_interrupt_weights[pos_irq];
1015 		if (pos_weight < best_weight) {
1016 			best_weight = pos_weight;
1017 			best_irq = pos_irq;
1018 		}
1019 	}
1020 
1021 	/*
1022 	 * If this is an ISA IRQ, try using the SCI if it is also an ISA
1023 	 * interrupt as a fallback.
1024 	 */
1025 	if (link->l_isa_irq && !PCI_INTERRUPT_VALID(best_irq)) {
1026 		pos_irq = AcpiGbl_FADT.SciInterrupt;
1027 		pos_weight = pci_link_interrupt_weights[pos_irq];
1028 		if (pos_weight < best_weight) {
1029 			best_weight = pos_weight;
1030 			best_irq = pos_irq;
1031 		}
1032 	}
1033 
1034 	if (PCI_INTERRUPT_VALID(best_irq)) {
1035 		aprint_verbose("%s: Picked IRQ %u with weight %d\n",
1036 		    sc->pl_name, best_irq, best_weight);
1037 	} else
1038 		printf("%s: Unable to choose an IRQ\n", sc->pl_name);
1039 	return (best_irq);
1040 }
1041 
1042 int
1043 acpi_pci_link_route_interrupt(void *v, int index, int *irq, int *pol, int *trig)
1044 {
1045 	struct acpi_pci_link_softc *sc = v;
1046 	struct link *link;
1047 	int i;
1048 	pcireg_t reg;
1049 
1050 	ACPI_SERIAL_BEGIN(pci_link);
1051 	link = acpi_pci_link_lookup(sc, index);
1052 	if (link == NULL)
1053 		panic("%s: apparently invalid index %d", __func__, index);
1054 
1055 	/*
1056 	 * If this link device is already routed to an interrupt, just return
1057 	 * the interrupt it is routed to.
1058 	 */
1059 	if (link->l_routed) {
1060 		KASSERT(PCI_INTERRUPT_VALID(link->l_irq));
1061 		ACPI_SERIAL_END(pci_link);
1062 		*irq = link->l_irq;
1063 		*pol = link->l_pol;
1064 		*trig = link->l_trig;
1065 		return (link->l_irq);
1066 	}
1067 
1068 	/* Choose an IRQ if we need one. */
1069 	if (PCI_INTERRUPT_VALID(link->l_irq)) {
1070 		*irq = link->l_irq;
1071 		*pol = link->l_pol;
1072 		*trig = link->l_trig;
1073 		goto done;
1074 	}
1075 
1076 	link->l_irq = acpi_pci_link_choose_irq(sc, link);
1077 
1078 	/*
1079 	 * Try to route the interrupt we picked.  If it fails, then
1080 	 * assume the interrupt is not routed.
1081 	 */
1082 	if (!PCI_INTERRUPT_VALID(link->l_irq))
1083 		goto done;
1084 
1085 	acpi_pci_link_route_irqs(sc, irq, pol, trig);
1086 	if (!link->l_routed) {
1087 		link->l_irq = PCI_INVALID_IRQ;
1088 		goto done;
1089 	}
1090 
1091 	link->l_pol = *pol;
1092 	link->l_trig = *trig;
1093 	for (i = 0; i < link->l_dev_count; ++i) {
1094 		reg = pci_conf_read(acpi_softc->sc_pc, link->l_devices[i],
1095 		    PCI_INTERRUPT_REG);
1096 		reg &= ~(PCI_INTERRUPT_LINE_MASK << PCI_INTERRUPT_LINE_SHIFT);
1097 		reg |= link->l_irq << PCI_INTERRUPT_LINE_SHIFT;
1098 		pci_conf_write(acpi_softc->sc_pc, link->l_devices[i],
1099 		    PCI_INTERRUPT_REG, reg);
1100 	}
1101 
1102 done:
1103 	ACPI_SERIAL_END(pci_link);
1104 
1105 	return (link->l_irq);
1106 }
1107 
1108 /*
1109  * This is gross, but we abuse the identify routine to perform one-time
1110  * SYSINIT() style initialization for the driver.
1111  */
1112 static void
1113 acpi_pci_link_init(struct acpi_pci_link_softc *sc)
1114 {
1115 	ACPI_BUFFER buf;
1116 
1117 	/*
1118 	 * If the SCI is an ISA IRQ, add it to the bitmask of known good
1119 	 * ISA IRQs.
1120 	 *
1121 	 * XXX: If we are using the APIC, the SCI might have been
1122 	 * rerouted to an APIC pin in which case this is invalid.  However,
1123 	 * if we are using the APIC, we also shouldn't be having any PCI
1124 	 * interrupts routed via ISA IRQs, so this is probably ok.
1125 	 */
1126 	if (AcpiGbl_FADT.SciInterrupt < NUM_ISA_INTERRUPTS)
1127 		pci_link_bios_isa_irqs |= (1 << AcpiGbl_FADT.SciInterrupt);
1128 
1129 	buf.Length = sizeof (sc->pl_name);
1130 	buf.Pointer = sc->pl_name;
1131 
1132 	if (ACPI_FAILURE(AcpiGetName(sc->pl_handle, ACPI_SINGLE_NAME, &buf)))
1133 		snprintf(sc->pl_name, sizeof (sc->pl_name), "%s",
1134 		    "ACPI link device");
1135 
1136 	acpi_pci_link_attach(sc);
1137 }
1138 
1139 void *
1140 acpi_pci_link_devbyhandle(ACPI_HANDLE handle)
1141 {
1142 	struct acpi_pci_link_softc *sc;
1143 
1144 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
1145 		if (sc->pl_handle == handle)
1146 			return sc;
1147 	}
1148 
1149 	sc = malloc(sizeof (*sc), M_ACPI, M_NOWAIT | M_ZERO);
1150 	if (sc == NULL)
1151 		return NULL;
1152 
1153 	sc->pl_handle = handle;
1154 
1155 	acpi_pci_link_init(sc);
1156 
1157 	TAILQ_INSERT_TAIL(&acpi_pci_linkdevs, sc, pl_list);
1158 
1159 	return (void *)sc;
1160 }
1161 
1162 void
1163 acpi_pci_link_resume(void)
1164 {
1165 	struct acpi_pci_link_softc *sc;
1166 	ACPI_BUFFER srsbuf;
1167 
1168 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
1169 		ACPI_SERIAL_BEGIN(pci_link);
1170 		if (ACPI_SUCCESS(acpi_pci_link_srs(sc, &srsbuf)))
1171 			ACPI_FREE(srsbuf.Pointer);
1172 		ACPI_SERIAL_END(pci_link);
1173 	}
1174 }
1175 
1176 ACPI_HANDLE
1177 acpi_pci_link_handle(void *v)
1178 {
1179 	struct acpi_pci_link_softc *sc = v;
1180 
1181 	return sc->pl_handle;
1182 }
1183 
1184 char *
1185 acpi_pci_link_name(void *v)
1186 {
1187 	struct acpi_pci_link_softc *sc = v;
1188 
1189 	return sc->pl_name;
1190 }
1191 
1192 
1193 /*
1194  * Append an ACPI_RESOURCE to an ACPI_BUFFER.
1195  *
1196  * Given a pointer to an ACPI_RESOURCE structure, expand the ACPI_BUFFER
1197  * provided to contain it.  If the ACPI_BUFFER is empty, allocate a sensible
1198  * backing block.  If the ACPI_RESOURCE is NULL, return an empty set of
1199  * resources.
1200  */
1201 #define ACPI_INITIAL_RESOURCE_BUFFER_SIZE	512
1202 
1203 static ACPI_STATUS
1204 acpi_AppendBufferResource(ACPI_BUFFER *buf, ACPI_RESOURCE *res)
1205 {
1206 	ACPI_RESOURCE	*rp;
1207 	void		*newp;
1208 
1209 	/* Initialise the buffer if necessary. */
1210 	if (buf->Pointer == NULL) {
1211 	buf->Length = ACPI_INITIAL_RESOURCE_BUFFER_SIZE;
1212 	if ((buf->Pointer = ACPI_ALLOCATE(buf->Length)) == NULL)
1213 		return (AE_NO_MEMORY);
1214 	rp = (ACPI_RESOURCE *)buf->Pointer;
1215 	rp->Type =  ACPI_RESOURCE_TYPE_END_TAG;
1216 	rp->Length = 0;
1217 	}
1218 
1219 	if (res == NULL)
1220 		return (AE_OK);
1221 
1222 	/*
1223 	 * Scan the current buffer looking for the terminator.
1224 	 * This will either find the terminator or hit the end
1225 	 * of the buffer and return an error.
1226 	 */
1227 	rp = (ACPI_RESOURCE *)buf->Pointer;
1228 	for (;;) {
1229 		/* Range check, don't go outside the buffer */
1230 		if (rp >= (ACPI_RESOURCE *)((u_int8_t *)buf->Pointer +
1231 		    buf->Length))
1232 			return (AE_BAD_PARAMETER);
1233 		if (rp->Type ==  ACPI_RESOURCE_TYPE_END_TAG || rp->Length == 0)
1234 			break;
1235 		rp = ACPI_NEXT_RESOURCE(rp);
1236 	}
1237 
1238 	/*
1239 	 * Check the size of the buffer and expand if required.
1240 	 *
1241 	 * Required size is:
1242 	 *	size of existing resources before terminator +
1243 	 *	size of new resource and header +
1244 	 * 	size of terminator.
1245 	 *
1246 	 * Note that this loop should really only run once, unless
1247 	 * for some reason we are stuffing a *really* huge resource.
1248 	 */
1249 	while ((((u_int8_t *)rp - (u_int8_t *)buf->Pointer) +
1250 	    res->Length + ACPI_RS_SIZE_NO_DATA +
1251 	    ACPI_RS_SIZE_MIN) >= buf->Length) {
1252 		if ((newp = ACPI_ALLOCATE(buf->Length * 2)) == NULL)
1253 			return (AE_NO_MEMORY);
1254 		memcpy(newp, buf->Pointer, buf->Length);
1255 		rp = (ACPI_RESOURCE *)((u_int8_t *)newp +
1256 		   ((u_int8_t *)rp - (u_int8_t *)buf->Pointer));
1257 		ACPI_FREE(buf->Pointer);
1258 		buf->Pointer = newp;
1259 		buf->Length += buf->Length;
1260 	}
1261 
1262 	/* Insert the new resource. */
1263 	memcpy(rp, res, res->Length + ACPI_RS_SIZE_NO_DATA);
1264 
1265 	/* And add the terminator. */
1266 	rp = ACPI_NEXT_RESOURCE(rp);
1267 	rp->Type =  ACPI_RESOURCE_TYPE_END_TAG;
1268 	rp->Length = 0;
1269 
1270 	return (AE_OK);
1271 }
1272