xref: /netbsd-src/sys/dev/acpi/acpi_pci_link.c (revision 3816d47b2c42fcd6e549e3407f842a5b1a1d23ad)
1 /*	$NetBSD: acpi_pci_link.c,v 1.15 2009/09/16 10:47:54 mlelstv 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 1.15 2009/09/16 10:47:54 mlelstv 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 _COMPONENT          ACPI_BUS_COMPONENT
47 ACPI_MODULE_NAME            ("acpi_pci_link")
48 
49 
50 #define NUM_ISA_INTERRUPTS	16
51 #define NUM_ACPI_INTERRUPTS	256
52 
53 #define PCI_INVALID_IRQ	255
54 #define PCI_INTERRUPT_VALID(x) ((x) != PCI_INVALID_IRQ && (x) != 0)
55 
56 #define ACPI_SERIAL_BEGIN(x)
57 #define ACPI_SERIAL_END(x)
58 
59 /*
60  * An ACPI PCI link device may contain multiple links.  Each link has its
61  * own ACPI resource.  _PRT entries specify which link is being used via
62  * the Source Index.
63  *
64  * XXX: A note about Source Indices and DPFs:  Currently we assume that
65  * the DPF start and end tags are not counted towards the index that
66  * Source Index corresponds to.  Also, we assume that when DPFs are in use
67  * they various sets overlap in terms of Indices.  Here's an example
68  * resource list indicating these assumptions:
69  *
70  * Resource		Index
71  * --------		-----
72  * I/O Port		0
73  * Start DPF		-
74  * IRQ			1
75  * MemIO		2
76  * Start DPF		-
77  * IRQ			1
78  * MemIO		2
79  * End DPF		-
80  * DMA Channel		3
81  *
82  * The XXX is because I'm not sure if this is a valid assumption to make.
83  */
84 
85 /* States during DPF processing. */
86 #define	DPF_OUTSIDE	0
87 #define	DPF_FIRST	1
88 #define	DPF_IGNORE	2
89 
90 struct link;
91 
92 struct acpi_pci_link_softc {
93 	int	pl_num_links;
94 	int	pl_crs_bad;
95 	struct link *pl_links;
96 	char pl_name[32];
97 	ACPI_HANDLE pl_handle;
98 	TAILQ_ENTRY(acpi_pci_link_softc) pl_list;
99 };
100 
101 static TAILQ_HEAD(, acpi_pci_link_softc) acpi_pci_linkdevs =
102     TAILQ_HEAD_INITIALIZER(acpi_pci_linkdevs);
103 
104 
105 struct link {
106 	struct acpi_pci_link_softc *l_sc;
107 	uint8_t	l_bios_irq;
108 	uint8_t	l_irq;
109 	uint8_t l_trig;
110 	uint8_t l_pol;
111 	uint8_t	l_initial_irq;
112 	int	l_res_index;
113 	int	l_num_irqs;
114 	int	*l_irqs;
115 	int	l_references;
116 	int	l_dev_count;
117 	pcitag_t *l_devices;
118 	int	l_routed:1;
119 	int	l_isa_irq:1;
120 	ACPI_RESOURCE l_prs_template;
121 };
122 
123 struct link_count_request {
124 	int	in_dpf;
125 	int	count;
126 };
127 
128 struct link_res_request {
129 	struct acpi_pci_link_softc *sc;
130 	int	in_dpf;
131 	int	res_index;
132 	int	link_index;
133 };
134 
135 MALLOC_DEFINE(M_PCI_LINK, "pci_link", "ACPI PCI Link structures");
136 
137 static int pci_link_interrupt_weights[NUM_ACPI_INTERRUPTS];
138 static int pci_link_bios_isa_irqs;
139 
140 static ACPI_STATUS acpi_count_irq_resources(ACPI_RESOURCE *, void *);
141 static ACPI_STATUS link_add_crs(ACPI_RESOURCE *, void *);
142 static ACPI_STATUS link_add_prs(ACPI_RESOURCE *, void *);
143 static int link_valid_irq(struct link *, int);
144 static void acpi_pci_link_dump(struct acpi_pci_link_softc *);
145 static int acpi_pci_link_attach(struct acpi_pci_link_softc *);
146 static uint8_t acpi_pci_link_search_irq(struct acpi_pci_link_softc *, int, int,
147 					int);
148 static struct link *acpi_pci_link_lookup(struct acpi_pci_link_softc *, int);
149 static ACPI_STATUS acpi_pci_link_srs(struct acpi_pci_link_softc *,
150 				     ACPI_BUFFER *);
151 static ACPI_STATUS acpi_AppendBufferResource(ACPI_BUFFER *, ACPI_RESOURCE *);
152 
153 static ACPI_STATUS
154 acpi_count_irq_resources(ACPI_RESOURCE *res, void *context)
155 {
156 	struct link_count_request *req;
157 
158 	req = (struct link_count_request *)context;
159 	switch (res->Type) {
160 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
161 		switch (req->in_dpf) {
162 		case DPF_OUTSIDE:
163 			/* We've started the first DPF. */
164 			req->in_dpf = DPF_FIRST;
165 			break;
166 		case DPF_FIRST:
167 			/* We've started the second DPF. */
168 			req->in_dpf = DPF_IGNORE;
169 			break;
170 		}
171 		break;
172 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
173 		/* We are finished with DPF parsing. */
174 		KASSERT(req->in_dpf != DPF_OUTSIDE);
175 		req->in_dpf = DPF_OUTSIDE;
176 		break;
177 	case ACPI_RESOURCE_TYPE_IRQ:
178 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
179 		/*
180 		 * Don't count resources if we are in a DPF set that we are
181 		 * ignoring.
182 		 */
183 		if (req->in_dpf != DPF_IGNORE)
184 			req->count++;
185 	}
186 	return (AE_OK);
187 }
188 
189 static ACPI_STATUS
190 link_add_crs(ACPI_RESOURCE *res, void *context)
191 {
192 	struct link_res_request *req;
193 	struct link *link;
194 
195 	req = (struct link_res_request *)context;
196 	switch (res->Type) {
197 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
198 		switch (req->in_dpf) {
199 		case DPF_OUTSIDE:
200 			/* We've started the first DPF. */
201 			req->in_dpf = DPF_FIRST;
202 			break;
203 		case DPF_FIRST:
204 			/* We've started the second DPF. */
205 			panic(
206 		"%s: Multiple dependent functions within a current resource",
207 			    __func__);
208 			break;
209 		}
210 		break;
211 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
212 		/* We are finished with DPF parsing. */
213 		KASSERT(req->in_dpf != DPF_OUTSIDE);
214 		req->in_dpf = DPF_OUTSIDE;
215 		break;
216 	case ACPI_RESOURCE_TYPE_IRQ:
217 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
218 		KASSERT(req->link_index < req->sc->pl_num_links);
219 		link = &req->sc->pl_links[req->link_index];
220 		link->l_res_index = req->res_index;
221 		req->link_index++;
222 		req->res_index++;
223 
224 		/*
225 		 * Only use the current value if there's one IRQ.  Some
226 		 * systems return multiple IRQs (which is nonsense for _CRS)
227 		 * when the link hasn't been programmed.
228 		 */
229 		if (res->Type == ACPI_RESOURCE_TYPE_IRQ) {
230 			if (res->Data.Irq.InterruptCount == 1) {
231 				link->l_irq = res->Data.Irq.Interrupts[0];
232 				link->l_trig = res->Data.Irq.Triggering;
233 				link->l_pol = res->Data.Irq.Polarity;
234 			}
235 		} else if (res->Data.ExtendedIrq.InterruptCount == 1) {
236 			link->l_irq = res->Data.ExtendedIrq.Interrupts[0];
237 			link->l_trig = res->Data.ExtendedIrq.Triggering;
238 			link->l_pol = res->Data.ExtendedIrq.Polarity;
239 		}
240 
241 		/*
242 		 * An IRQ of zero means that the link isn't routed.
243 		 */
244 		if (link->l_irq == 0)
245 			link->l_irq = PCI_INVALID_IRQ;
246 		break;
247 	default:
248 		req->res_index++;
249 	}
250 	return (AE_OK);
251 }
252 
253 /*
254  * Populate the set of possible IRQs for each device.
255  */
256 static ACPI_STATUS
257 link_add_prs(ACPI_RESOURCE *res, void *context)
258 {
259 	struct link_res_request *req;
260 	struct link *link;
261 	UINT8 *irqs = NULL;
262 	UINT32 *ext_irqs = NULL;
263 	int i, is_ext_irq = 1;
264 
265 	req = (struct link_res_request *)context;
266 	switch (res->Type) {
267 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
268 		switch (req->in_dpf) {
269 		case DPF_OUTSIDE:
270 			/* We've started the first DPF. */
271 			req->in_dpf = DPF_FIRST;
272 			break;
273 		case DPF_FIRST:
274 			/* We've started the second DPF. */
275 			req->in_dpf = DPF_IGNORE;
276 			break;
277 		}
278 		break;
279 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
280 		/* We are finished with DPF parsing. */
281 		KASSERT(req->in_dpf != DPF_OUTSIDE);
282 		req->in_dpf = DPF_OUTSIDE;
283 		break;
284 	case ACPI_RESOURCE_TYPE_IRQ:
285 		is_ext_irq = 0;
286 		/* fall through */
287 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
288 		/*
289 		 * Don't parse resources if we are in a DPF set that we are
290 		 * ignoring.
291 		 */
292 		if (req->in_dpf == DPF_IGNORE)
293 			break;
294 
295 		KASSERT(req->link_index < req->sc->pl_num_links);
296 		link = &req->sc->pl_links[req->link_index];
297 		if (link->l_res_index == -1) {
298 			KASSERT(req->sc->pl_crs_bad);
299 			link->l_res_index = req->res_index;
300 		}
301 		req->link_index++;
302 		req->res_index++;
303 
304 		/*
305 		 * Stash a copy of the resource for later use when
306 		 * doing _SRS.
307 		 *
308 		 * Note that in theory res->Length may exceed the size
309 		 * of ACPI_RESOURCE, due to variable length lists in
310 		 * subtypes.  However, all uses of l_prs_template only
311 		 * rely on lists lengths of zero or one, for which
312 		 * sizeof(ACPI_RESOURCE) is sufficient space anyway.
313 		 * We cannot read longer than Length bytes, in case we
314 		 * read off the end of mapped memory.  So we read
315 		 * whichever length is shortest, Length or
316 		 * sizeof(ACPI_RESOURCE).
317 		 */
318 		KASSERT(res->Length >= ACPI_RS_SIZE_MIN);
319 
320 		memset(&link->l_prs_template, 0, sizeof(link->l_prs_template));
321 		memcpy(&link->l_prs_template, res,
322 		       MIN(res->Length, sizeof(link->l_prs_template)));
323 
324 		if (is_ext_irq) {
325 			link->l_num_irqs =
326 			    res->Data.ExtendedIrq.InterruptCount;
327 			link->l_trig = res->Data.ExtendedIrq.Triggering;
328 			link->l_pol = res->Data.ExtendedIrq.Polarity;
329 			ext_irqs = res->Data.ExtendedIrq.Interrupts;
330 		} else {
331 			link->l_num_irqs = res->Data.Irq.InterruptCount;
332 			link->l_trig = res->Data.Irq.Triggering;
333 			link->l_pol = res->Data.Irq.Polarity;
334 			irqs = res->Data.Irq.Interrupts;
335 		}
336 		if (link->l_num_irqs == 0)
337 			break;
338 
339 		/*
340 		 * Save a list of the valid IRQs.  Also, if all of the
341 		 * valid IRQs are ISA IRQs, then mark this link as
342 		 * routed via an ISA interrupt.
343 		 */
344 		link->l_isa_irq = TRUE;
345 		link->l_irqs = malloc(sizeof(int) * link->l_num_irqs,
346 		    M_PCI_LINK, M_WAITOK | M_ZERO);
347 		for (i = 0; i < link->l_num_irqs; i++) {
348 			if (is_ext_irq) {
349 				link->l_irqs[i] = ext_irqs[i];
350 				if (ext_irqs[i] >= NUM_ISA_INTERRUPTS)
351 					link->l_isa_irq = FALSE;
352 			} else {
353 				link->l_irqs[i] = irqs[i];
354 				if (irqs[i] >= NUM_ISA_INTERRUPTS)
355 					link->l_isa_irq = FALSE;
356 			}
357 		}
358 		break;
359 	default:
360 		if (req->in_dpf == DPF_IGNORE)
361 			break;
362 		if (req->sc->pl_crs_bad)
363 			aprint_normal("%s: Warning: possible resource %d "
364 			       "will be lost during _SRS\n", req->sc->pl_name,
365 			       req->res_index);
366 		req->res_index++;
367 	}
368 	return (AE_OK);
369 }
370 
371 static int
372 link_valid_irq(struct link *link, int irq)
373 {
374 	int i;
375 
376 	/* Invalid interrupts are never valid. */
377 	if (!PCI_INTERRUPT_VALID(irq))
378 		return (FALSE);
379 
380 	/* Any interrupt in the list of possible interrupts is valid. */
381 	for (i = 0; i < link->l_num_irqs; i++)
382 		if (link->l_irqs[i] == irq)
383 			 return (TRUE);
384 
385 	/*
386 	 * For links routed via an ISA interrupt, if the SCI is routed via
387 	 * an ISA interrupt, the SCI is always treated as a valid IRQ.
388 	 */
389 	if (link->l_isa_irq && AcpiGbl_FADT.SciInterrupt == irq &&
390 	    irq < NUM_ISA_INTERRUPTS)
391 		return (TRUE);
392 
393 	/* If the interrupt wasn't found in the list it is not valid. */
394 	return (FALSE);
395 }
396 
397 void
398 acpi_pci_link_state(void)
399 {
400 	struct acpi_pci_link_softc *sc;
401 
402 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
403 		acpi_pci_link_dump(sc);
404 	}
405 }
406 
407 static void
408 acpi_pci_link_dump(struct acpi_pci_link_softc *sc)
409 {
410 	struct link *link;
411 	int i, j;
412 
413 	printf("Link Device %s:\n", sc->pl_name);
414 	printf("Index  IRQ  Rtd  Ref  IRQs\n");
415 	for (i = 0; i < sc->pl_num_links; i++) {
416 		link = &sc->pl_links[i];
417 		printf("%5d  %3d   %c   %3d ", i, link->l_irq,
418 		    link->l_routed ? 'Y' : 'N',  link->l_references);
419 		if (link->l_num_irqs == 0)
420 			printf(" none");
421 		else for (j = 0; j < link->l_num_irqs; j++)
422 			printf(" %d", link->l_irqs[j]);
423 		printf(" polarity %u trigger %u\n", link->l_pol, link->l_trig);
424 	}
425 	printf("\n");
426 }
427 
428 static int
429 acpi_pci_link_attach(struct acpi_pci_link_softc *sc)
430 {
431 	struct link_count_request creq;
432 	struct link_res_request rreq;
433 	ACPI_STATUS status;
434 	int i;
435 
436 	ACPI_SERIAL_BEGIN(pci_link);
437 
438 	/*
439 	 * Count the number of current resources so we know how big of
440 	 * a link array to allocate.  On some systems, _CRS is broken,
441 	 * so for those systems try to derive the count from _PRS instead.
442 	 */
443 	creq.in_dpf = DPF_OUTSIDE;
444 	creq.count = 0;
445 	status = AcpiWalkResources(sc->pl_handle, "_CRS",
446 	    acpi_count_irq_resources, &creq);
447 	sc->pl_crs_bad = ACPI_FAILURE(status);
448 	if (sc->pl_crs_bad) {
449 		creq.in_dpf = DPF_OUTSIDE;
450 		creq.count = 0;
451 		status = AcpiWalkResources(sc->pl_handle, "_PRS",
452 		    acpi_count_irq_resources, &creq);
453 		if (ACPI_FAILURE(status)) {
454 			aprint_error("%s: Unable to parse _CRS or _PRS: %s\n",
455 			    sc->pl_name, AcpiFormatException(status));
456 			ACPI_SERIAL_END(pci_link);
457 			return (ENXIO);
458 		}
459 	}
460 	sc->pl_num_links = creq.count;
461 	if (creq.count == 0) {
462 		ACPI_SERIAL_END(pci_link);
463 		return (0);
464 	}
465 	sc->pl_links = malloc(sizeof(struct link) * sc->pl_num_links,
466 	    M_PCI_LINK, M_WAITOK | M_ZERO);
467 
468 	/* Initialize the child links. */
469 	for (i = 0; i < sc->pl_num_links; i++) {
470 		sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
471 		sc->pl_links[i].l_bios_irq = PCI_INVALID_IRQ;
472 		sc->pl_links[i].l_sc = sc;
473 		sc->pl_links[i].l_isa_irq = FALSE;
474 		sc->pl_links[i].l_res_index = -1;
475 		sc->pl_links[i].l_dev_count = 0;
476 		sc->pl_links[i].l_devices = NULL;
477 	}
478 
479 	/* Try to read the current settings from _CRS if it is valid. */
480 	if (!sc->pl_crs_bad) {
481 		rreq.in_dpf = DPF_OUTSIDE;
482 		rreq.link_index = 0;
483 		rreq.res_index = 0;
484 		rreq.sc = sc;
485 		status = AcpiWalkResources(sc->pl_handle, "_CRS",
486 		    link_add_crs, &rreq);
487 		if (ACPI_FAILURE(status)) {
488 			aprint_error("%s: Unable to parse _CRS: %s\n",
489 			    sc->pl_name, AcpiFormatException(status));
490 			goto fail;
491 		}
492 	}
493 
494 	/*
495 	 * Try to read the possible settings from _PRS.  Note that if the
496 	 * _CRS is toast, we depend on having a working _PRS.  However, if
497 	 * _CRS works, then it is ok for _PRS to be missing.
498 	 */
499 	rreq.in_dpf = DPF_OUTSIDE;
500 	rreq.link_index = 0;
501 	rreq.res_index = 0;
502 	rreq.sc = sc;
503 	status = AcpiWalkResources(sc->pl_handle, "_PRS",
504 	    link_add_prs, &rreq);
505 	if (ACPI_FAILURE(status) &&
506 	    (status != AE_NOT_FOUND || sc->pl_crs_bad)) {
507 		aprint_error("%s: Unable to parse _PRS: %s\n",
508 		    sc->pl_name, AcpiFormatException(status));
509 		goto fail;
510 	}
511 	if (boothowto & AB_VERBOSE) {
512 		aprint_normal("%s: Links after initial probe:\n", sc->pl_name);
513 		acpi_pci_link_dump(sc);
514 	}
515 
516 	/* Verify initial IRQs if we have _PRS. */
517 	if (status != AE_NOT_FOUND)
518 		for (i = 0; i < sc->pl_num_links; i++)
519 			if (!link_valid_irq(&sc->pl_links[i],
520 			    sc->pl_links[i].l_irq))
521 				sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
522 	if (boothowto & AB_VERBOSE) {
523 		printf("%s: Links after initial validation:\n", sc->pl_name);
524 		acpi_pci_link_dump(sc);
525 	}
526 
527 	/* Save initial IRQs. */
528 	for (i = 0; i < sc->pl_num_links; i++)
529 		sc->pl_links[i].l_initial_irq = sc->pl_links[i].l_irq;
530 
531 	/*
532 	 * Try to disable this link.  If successful, set the current IRQ to
533 	 * zero and flags to indicate this link is not routed.  If we can't
534 	 * run _DIS (i.e., the method doesn't exist), assume the initial
535 	 * IRQ was routed by the BIOS.
536 	 */
537 #if 0	/* XXX causes spontaneaous resets on some systems. Disabled for now. */
538 	if (ACPI_SUCCESS(AcpiEvaluateObject(sc->pl_handle, "_DIS", NULL,
539 	    NULL)))
540 		for (i = 0; i < sc->pl_num_links; i++)
541 			sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
542 	else
543 #endif
544 		for (i = 0; i < sc->pl_num_links; i++)
545 			if (PCI_INTERRUPT_VALID(sc->pl_links[i].l_irq))
546 				sc->pl_links[i].l_routed = TRUE;
547 	if (boothowto & AB_VERBOSE) {
548 		printf("%s: Links after disable:\n", sc->pl_name);
549 		acpi_pci_link_dump(sc);
550 	}
551 	ACPI_SERIAL_END(pci_link);
552 	return (0);
553 fail:
554 	ACPI_SERIAL_END(pci_link);
555 	for (i = 0; i < sc->pl_num_links; i++) {
556 		if (sc->pl_links[i].l_irqs != NULL)
557 			free(sc->pl_links[i].l_irqs, M_PCI_LINK);
558 		if (sc->pl_links[i].l_devices != NULL)
559 			free(sc->pl_links[i].l_devices, M_PCI_LINK);
560 	}
561 	free(sc->pl_links, M_PCI_LINK);
562 	return (ENXIO);
563 }
564 
565 static void
566 acpi_pci_link_add_functions(struct acpi_pci_link_softc *sc, struct link *link,
567     int bus, int device, int pin)
568 {
569 	uint32_t value;
570 	uint8_t func, maxfunc, ipin;
571 	pcitag_t tag;
572 
573 	tag = pci_make_tag(acpi_softc->sc_pc, bus, device, 0);
574 	/* See if we have a valid device at function 0. */
575 	value = pci_conf_read(acpi_softc->sc_pc, tag,  PCI_BHLC_REG);
576 	if (PCI_HDRTYPE_TYPE(value) > PCI_HDRTYPE_PCB)
577 		return;
578 	if (PCI_HDRTYPE_MULTIFN(value))
579 		maxfunc = 7;
580 	else
581 		maxfunc = 0;
582 
583 	/* Scan all possible functions at this device. */
584 	for (func = 0; func <= maxfunc; func++) {
585 		tag = pci_make_tag(acpi_softc->sc_pc, bus, device, func);
586 		value = pci_conf_read(acpi_softc->sc_pc, tag, PCI_ID_REG);
587 		if (PCI_VENDOR(value) == 0xffff)
588 			continue;
589 		value = pci_conf_read(acpi_softc->sc_pc, tag,
590 		    PCI_INTERRUPT_REG);
591 		ipin = PCI_INTERRUPT_PIN(value);
592 		/*
593 		 * See if it uses the pin in question.  Note that the passed
594 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
595 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
596 		 */
597 		if (ipin != pin + 1)
598 			continue;
599 
600 		link->l_devices = realloc(link->l_devices,
601 		    sizeof(pcitag_t) * (link->l_dev_count + 1),
602 		    M_PCI_LINK, M_WAITOK);
603 		link->l_devices[link->l_dev_count] = tag;
604 		++link->l_dev_count;
605 	}
606 }
607 
608 static uint8_t
609 acpi_pci_link_search_irq(struct acpi_pci_link_softc *sc, int bus, int device,
610 			 int pin)
611 {
612 	uint32_t value;
613 	uint8_t func, maxfunc, ipin, iline;
614 	pcitag_t tag;
615 
616 	tag = pci_make_tag(acpi_softc->sc_pc, bus, device, 0);
617 	/* See if we have a valid device at function 0. */
618 	value = pci_conf_read(acpi_softc->sc_pc, tag,  PCI_BHLC_REG);
619 	if (PCI_HDRTYPE_TYPE(value) > PCI_HDRTYPE_PCB)
620 		return (PCI_INVALID_IRQ);
621 	if (PCI_HDRTYPE_MULTIFN(value))
622 		maxfunc = 7;
623 	else
624 		maxfunc = 0;
625 
626 	/* Scan all possible functions at this device. */
627 	for (func = 0; func <= maxfunc; func++) {
628 		tag = pci_make_tag(acpi_softc->sc_pc, bus, device, func);
629 		value = pci_conf_read(acpi_softc->sc_pc, tag, PCI_ID_REG);
630 		if (PCI_VENDOR(value) == 0xffff)
631 			continue;
632 		value = pci_conf_read(acpi_softc->sc_pc, tag,
633 		    PCI_INTERRUPT_REG);
634 		ipin = PCI_INTERRUPT_PIN(value);
635 		iline = PCI_INTERRUPT_LINE(value);
636 
637 		/*
638 		 * See if it uses the pin in question.  Note that the passed
639 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
640 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
641 		 */
642 		if (ipin != pin + 1)
643 			continue;
644 		aprint_verbose(
645 		    "%s: ACPI: Found matching pin for %d.%d.INT%c"
646 	            " at func %d: %d\n",
647 			    sc->pl_name, bus, device, pin + 'A', func, iline);
648 		if (PCI_INTERRUPT_VALID(iline))
649 			return (iline);
650 	}
651 	return (PCI_INVALID_IRQ);
652 }
653 
654 /*
655  * Find the link structure that corresponds to the resource index passed in
656  * via 'source_index'.
657  */
658 static struct link *
659 acpi_pci_link_lookup(struct acpi_pci_link_softc *sc, int source_index)
660 {
661 	int i;
662 
663 	for (i = 0; i < sc->pl_num_links; i++)
664 		if (sc->pl_links[i].l_res_index == source_index)
665 			return (&sc->pl_links[i]);
666 	return (NULL);
667 }
668 
669 void
670 acpi_pci_link_add_reference(void *v, int index, int bus, int slot, int pin)
671 {
672 	struct acpi_pci_link_softc *sc = v;
673 	struct link *link;
674 	uint8_t bios_irq;
675 
676 	/* Bump the reference count. */
677 	ACPI_SERIAL_BEGIN(pci_link);
678 	link = acpi_pci_link_lookup(sc, index);
679 	if (link == NULL) {
680 		printf("%s: apparently invalid index %d\n", sc->pl_name, index);
681 		ACPI_SERIAL_END(pci_link);
682 		return;
683 	}
684 	link->l_references++;
685 	acpi_pci_link_add_functions(sc, link, bus, slot, pin);
686 	if (link->l_routed)
687 		pci_link_interrupt_weights[link->l_irq]++;
688 
689 	/*
690 	 * The BIOS only routes interrupts via ISA IRQs using the ATPICs
691 	 * (8259As).  Thus, if this link is routed via an ISA IRQ, go
692 	 * look to see if the BIOS routed an IRQ for this link at the
693 	 * indicated (bus, slot, pin).  If so, we prefer that IRQ for
694 	 * this link and add that IRQ to our list of known-good IRQs.
695 	 * This provides a good work-around for link devices whose _CRS
696 	 * method is either broken or bogus.  We only use the value
697 	 * returned by _CRS if we can't find a valid IRQ via this method
698 	 * in fact.
699 	 *
700 	 * If this link is not routed via an ISA IRQ (because we are using
701 	 * APIC for example), then don't bother looking up the BIOS IRQ
702 	 * as if we find one it won't be valid anyway.
703 	 */
704 	if (!link->l_isa_irq) {
705 		ACPI_SERIAL_END(pci_link);
706 		return;
707 	}
708 
709 	/* Try to find a BIOS IRQ setting from any matching devices. */
710 	bios_irq = acpi_pci_link_search_irq(sc, bus, slot, pin);
711 	if (!PCI_INTERRUPT_VALID(bios_irq)) {
712 		ACPI_SERIAL_END(pci_link);
713 		return;
714 	}
715 
716 	/* Validate the BIOS IRQ. */
717 	if (!link_valid_irq(link, bios_irq)) {
718 		printf("%s: BIOS IRQ %u for %d.%d.INT%c is invalid\n",
719 		    sc->pl_name, bios_irq, (int)bus, slot, pin + 'A');
720 	} else if (!PCI_INTERRUPT_VALID(link->l_bios_irq)) {
721 		link->l_bios_irq = bios_irq;
722 		if (bios_irq < NUM_ISA_INTERRUPTS)
723 			pci_link_bios_isa_irqs |= (1 << bios_irq);
724 		if (bios_irq != link->l_initial_irq &&
725 		    PCI_INTERRUPT_VALID(link->l_initial_irq))
726 			printf(
727 			    "%s: BIOS IRQ %u does not match initial IRQ %u\n",
728 			    sc->pl_name, bios_irq, link->l_initial_irq);
729 	} else if (bios_irq != link->l_bios_irq)
730 		printf(
731 	    "%s: BIOS IRQ %u for %d.%d.INT%c does not match "
732 	    "previous BIOS IRQ %u\n",
733 		    sc->pl_name, bios_irq, (int)bus, slot, pin + 'A',
734 		    link->l_bios_irq);
735 	ACPI_SERIAL_END(pci_link);
736 }
737 
738 static ACPI_STATUS
739 acpi_pci_link_srs_from_crs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
740 {
741 	ACPI_RESOURCE *resource, *end, newres, *resptr;
742 	ACPI_BUFFER crsbuf;
743 	ACPI_STATUS status;
744 	struct link *link;
745 	int i, in_dpf;
746 
747 	/* Fetch the _CRS. */
748 	crsbuf.Pointer = NULL;
749 	crsbuf.Length = ACPI_ALLOCATE_LOCAL_BUFFER;
750 	status = AcpiGetCurrentResources(sc->pl_handle, &crsbuf);
751 	if (ACPI_SUCCESS(status) && crsbuf.Pointer == NULL)
752 		status = AE_NO_MEMORY;
753 	if (ACPI_FAILURE(status)) {
754 		aprint_verbose("%s: Unable to fetch current resources: %s\n",
755 		    sc->pl_name, AcpiFormatException(status));
756 		return (status);
757 	}
758 
759 	/* Fill in IRQ resources via link structures. */
760 	srsbuf->Pointer = NULL;
761 	link = sc->pl_links;
762 	i = 0;
763 	in_dpf = DPF_OUTSIDE;
764 	resource = (ACPI_RESOURCE *)crsbuf.Pointer;
765 	end = (ACPI_RESOURCE *)((char *)crsbuf.Pointer + crsbuf.Length);
766 	for (;;) {
767 		switch (resource->Type) {
768 		case ACPI_RESOURCE_TYPE_START_DEPENDENT:
769 			switch (in_dpf) {
770 			case DPF_OUTSIDE:
771 				/* We've started the first DPF. */
772 				in_dpf = DPF_FIRST;
773 				break;
774 			case DPF_FIRST:
775 				/* We've started the second DPF. */
776 				panic(
777 		"%s: Multiple dependent functions within a current resource",
778 				    __func__);
779 				break;
780 			}
781 			resptr = NULL;
782 			break;
783 		case ACPI_RESOURCE_TYPE_END_DEPENDENT:
784 			/* We are finished with DPF parsing. */
785 			KASSERT(in_dpf != DPF_OUTSIDE);
786 			in_dpf = DPF_OUTSIDE;
787 			resptr = NULL;
788 			break;
789 		case ACPI_RESOURCE_TYPE_IRQ:
790 			newres = link->l_prs_template;
791 			resptr = &newres;
792 			resptr->Data.Irq.InterruptCount = 1;
793 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
794 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS);
795 				resptr->Data.Irq.Interrupts[0] = link->l_irq;
796 				resptr->Data.Irq.Triggering = link->l_trig;
797 				resptr->Data.Irq.Polarity = link->l_pol;
798 			} else
799 				resptr->Data.Irq.Interrupts[0] = 0;
800 			link++;
801 			i++;
802 			break;
803 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
804 			newres = link->l_prs_template;
805 			resptr = &newres;
806 			resptr->Data.ExtendedIrq.InterruptCount = 1;
807 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
808 				resptr->Data.ExtendedIrq.Interrupts[0] =
809 				    link->l_irq;
810 				resptr->Data.ExtendedIrq.Triggering =
811 				    link->l_trig;
812 				resptr->Data.ExtendedIrq.Polarity = link->l_pol;
813 			} else
814 				resptr->Data.ExtendedIrq.Interrupts[0] = 0;
815 			link++;
816 			i++;
817 			break;
818 		default:
819 			resptr = resource;
820 		}
821 		if (resptr != NULL) {
822 			status = acpi_AppendBufferResource(srsbuf, resptr);
823 			if (ACPI_FAILURE(status)) {
824 				printf("%s: Unable to build resources: %s\n",
825 				    sc->pl_name, AcpiFormatException(status));
826 				if (srsbuf->Pointer != NULL)
827 					ACPI_FREE(srsbuf->Pointer);
828 				ACPI_FREE(crsbuf.Pointer);
829 				return (status);
830 			}
831 		}
832 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
833 			break;
834 		resource = ACPI_NEXT_RESOURCE(resource);
835 		if (resource >= end)
836 			break;
837 	}
838 	ACPI_FREE(crsbuf.Pointer);
839 	return (AE_OK);
840 }
841 
842 static ACPI_STATUS
843 acpi_pci_link_srs_from_links(struct acpi_pci_link_softc *sc,
844     ACPI_BUFFER *srsbuf)
845 {
846 	ACPI_RESOURCE newres;
847 	ACPI_STATUS status;
848 	struct link *link;
849 	int i;
850 
851 	/* Start off with an empty buffer. */
852 	srsbuf->Pointer = NULL;
853 	link = sc->pl_links;
854 	for (i = 0; i < sc->pl_num_links; i++) {
855 
856 		/* Add a new IRQ resource from each link. */
857 		link = &sc->pl_links[i];
858 		newres = link->l_prs_template;
859 		if (newres.Type == ACPI_RESOURCE_TYPE_IRQ) {
860 
861 			/* Build an IRQ resource. */
862 			newres.Data.Irq.InterruptCount = 1;
863 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
864 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS);
865 				newres.Data.Irq.Interrupts[0] = link->l_irq;
866 				newres.Data.Irq.Triggering = link->l_trig;
867 				newres.Data.Irq.Polarity = link->l_pol;
868 			} else
869 				newres.Data.Irq.Interrupts[0] = 0;
870 		} else {
871 
872 			/* Build an ExtIRQ resuorce. */
873 			newres.Data.ExtendedIrq.InterruptCount = 1;
874 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
875 				newres.Data.ExtendedIrq.Interrupts[0] =
876 				    link->l_irq;
877 				newres.Data.ExtendedIrq.Triggering =
878 				    link->l_trig;
879 				newres.Data.ExtendedIrq.Polarity =
880 				    link->l_pol;
881 			} else {
882 				newres.Data.ExtendedIrq.Interrupts[0] = 0;
883 			}
884 		}
885 
886 		/* Add the new resource to the end of the _SRS buffer. */
887 		status = acpi_AppendBufferResource(srsbuf, &newres);
888 		if (ACPI_FAILURE(status)) {
889 			printf("%s: Unable to build resources: %s\n",
890 			    sc->pl_name, AcpiFormatException(status));
891 			if (srsbuf->Pointer != NULL)
892 				ACPI_FREE(srsbuf->Pointer);
893 			return (status);
894 		}
895 	}
896 	return (AE_OK);
897 }
898 
899 static ACPI_STATUS
900 acpi_pci_link_srs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
901 {
902 	ACPI_STATUS status;
903 
904 	if (sc->pl_crs_bad)
905 		status = acpi_pci_link_srs_from_links(sc, srsbuf);
906 	else
907 		status = acpi_pci_link_srs_from_crs(sc, srsbuf);
908 
909 	/* Write out new resources via _SRS. */
910 	return AcpiSetCurrentResources(sc->pl_handle, srsbuf);
911 }
912 
913 static ACPI_STATUS
914 acpi_pci_link_route_irqs(struct acpi_pci_link_softc *sc, int *irq, int *pol,
915 			 int *trig)
916 {
917 	ACPI_RESOURCE *resource, *end;
918 	ACPI_BUFFER srsbuf;
919 	ACPI_STATUS status;
920 	struct link *link;
921 	int i, is_ext = 0;
922 
923 	status = acpi_pci_link_srs(sc, &srsbuf);
924 	if (ACPI_FAILURE(status)) {
925 		printf("%s: _SRS failed: %s\n",
926 		    sc->pl_name, AcpiFormatException(status));
927 		return (status);
928 	}
929 	/*
930 	 * Perform acpi_config_intr() on each IRQ resource if it was just
931 	 * routed for the first time.
932 	 */
933 	link = sc->pl_links;
934 	i = 0;
935 	resource = (ACPI_RESOURCE *)srsbuf.Pointer;
936 	end = (ACPI_RESOURCE *)((char *)srsbuf.Pointer + srsbuf.Length);
937 	for (;;) {
938 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
939 			break;
940 		switch (resource->Type) {
941 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
942 			is_ext = 1;
943 			/* FALLTHROUGH */
944 		case ACPI_RESOURCE_TYPE_IRQ:
945 			/*
946 			 * Only configure the interrupt and update the
947 			 * weights if this link has a valid IRQ and was
948 			 * previously unrouted.
949 			 */
950 			if (!link->l_routed &&
951 			    PCI_INTERRUPT_VALID(link->l_irq)) {
952 				*trig = is_ext ?
953 				    resource->Data.ExtendedIrq.Triggering :
954 				    resource->Data.Irq.Triggering;
955 				*pol = is_ext ?
956 				    resource->Data.ExtendedIrq.Polarity :
957 				    resource->Data.Irq.Polarity;
958 				*irq = is_ext ?
959 				    resource->Data.ExtendedIrq.Interrupts[0] :
960 				    resource->Data.Irq.Interrupts[0];
961 				link->l_routed = TRUE;
962 				pci_link_interrupt_weights[link->l_irq] +=
963 				    link->l_references;
964 			}
965 			link++;
966 			i++;
967 			break;
968 		}
969 		resource = ACPI_NEXT_RESOURCE(resource);
970 		if (resource >= end)
971 			break;
972 	}
973 	ACPI_FREE(srsbuf.Pointer);
974 	return (AE_OK);
975 }
976 
977 /*
978  * Pick an IRQ to use for this unrouted link.
979  */
980 static uint8_t
981 acpi_pci_link_choose_irq(struct acpi_pci_link_softc *sc, struct link *link)
982 {
983 	u_int8_t best_irq, pos_irq;
984 	int best_weight, pos_weight, i;
985 
986 	KASSERT(!link->l_routed);
987 	KASSERT(!PCI_INTERRUPT_VALID(link->l_irq));
988 
989 	/*
990 	 * If we have a valid BIOS IRQ, use that.  We trust what the BIOS
991 	 * says it routed over what _CRS says the link thinks is routed.
992 	 */
993 	if (PCI_INTERRUPT_VALID(link->l_bios_irq))
994 		return (link->l_bios_irq);
995 
996 	/*
997 	 * If we don't have a BIOS IRQ but do have a valid IRQ from _CRS,
998 	 * then use that.
999 	 */
1000 	if (PCI_INTERRUPT_VALID(link->l_initial_irq))
1001 		return (link->l_initial_irq);
1002 
1003 	/*
1004 	 * Ok, we have no useful hints, so we have to pick from the
1005 	 * possible IRQs.  For ISA IRQs we only use interrupts that
1006 	 * have already been used by the BIOS.
1007 	 */
1008 	best_irq = PCI_INVALID_IRQ;
1009 	best_weight = INT_MAX;
1010 	for (i = 0; i < link->l_num_irqs; i++) {
1011 		pos_irq = link->l_irqs[i];
1012 		if (pos_irq < NUM_ISA_INTERRUPTS &&
1013 		    (pci_link_bios_isa_irqs & 1 << pos_irq) == 0)
1014 			continue;
1015 		pos_weight = pci_link_interrupt_weights[pos_irq];
1016 		if (pos_weight < best_weight) {
1017 			best_weight = pos_weight;
1018 			best_irq = pos_irq;
1019 		}
1020 	}
1021 
1022 	/*
1023 	 * If this is an ISA IRQ, try using the SCI if it is also an ISA
1024 	 * interrupt as a fallback.
1025 	 */
1026 	if (link->l_isa_irq && !PCI_INTERRUPT_VALID(best_irq)) {
1027 		pos_irq = AcpiGbl_FADT.SciInterrupt;
1028 		pos_weight = pci_link_interrupt_weights[pos_irq];
1029 		if (pos_weight < best_weight) {
1030 			best_weight = pos_weight;
1031 			best_irq = pos_irq;
1032 		}
1033 	}
1034 
1035 	if (PCI_INTERRUPT_VALID(best_irq)) {
1036 		aprint_verbose("%s: Picked IRQ %u with weight %d\n",
1037 		    sc->pl_name, best_irq, best_weight);
1038 	} else
1039 		printf("%s: Unable to choose an IRQ\n", sc->pl_name);
1040 	return (best_irq);
1041 }
1042 
1043 int
1044 acpi_pci_link_route_interrupt(void *v, int index, int *irq, int *pol, int *trig)
1045 {
1046 	struct acpi_pci_link_softc *sc = v;
1047 	struct link *link;
1048 	int i;
1049 	pcireg_t reg;
1050 
1051 	ACPI_SERIAL_BEGIN(pci_link);
1052 	link = acpi_pci_link_lookup(sc, index);
1053 	if (link == NULL)
1054 		panic("%s: apparently invalid index %d", __func__, index);
1055 
1056 	/*
1057 	 * If this link device is already routed to an interrupt, just return
1058 	 * the interrupt it is routed to.
1059 	 */
1060 	if (link->l_routed) {
1061 		KASSERT(PCI_INTERRUPT_VALID(link->l_irq));
1062 		ACPI_SERIAL_END(pci_link);
1063 		*irq = link->l_irq;
1064 		*pol = link->l_pol;
1065 		*trig = link->l_trig;
1066 		return (link->l_irq);
1067 	}
1068 
1069 	/* Choose an IRQ if we need one. */
1070 	if (PCI_INTERRUPT_VALID(link->l_irq)) {
1071 		*irq = link->l_irq;
1072 		*pol = link->l_pol;
1073 		*trig = link->l_trig;
1074 		goto done;
1075 	}
1076 
1077 	link->l_irq = acpi_pci_link_choose_irq(sc, link);
1078 
1079 	/*
1080 	 * Try to route the interrupt we picked.  If it fails, then
1081 	 * assume the interrupt is not routed.
1082 	 */
1083 	if (!PCI_INTERRUPT_VALID(link->l_irq))
1084 		goto done;
1085 
1086 	acpi_pci_link_route_irqs(sc, irq, pol, trig);
1087 	if (!link->l_routed) {
1088 		link->l_irq = PCI_INVALID_IRQ;
1089 		goto done;
1090 	}
1091 
1092 	link->l_pol = *pol;
1093 	link->l_trig = *trig;
1094 	for (i = 0; i < link->l_dev_count; ++i) {
1095 		reg = pci_conf_read(acpi_softc->sc_pc, link->l_devices[i],
1096 		    PCI_INTERRUPT_REG);
1097 		reg &= ~(PCI_INTERRUPT_LINE_MASK << PCI_INTERRUPT_LINE_SHIFT);
1098 		reg |= link->l_irq << PCI_INTERRUPT_LINE_SHIFT;
1099 		pci_conf_write(acpi_softc->sc_pc, link->l_devices[i],
1100 		    PCI_INTERRUPT_REG, reg);
1101 	}
1102 
1103 done:
1104 	ACPI_SERIAL_END(pci_link);
1105 
1106 	return (link->l_irq);
1107 }
1108 
1109 /*
1110  * This is gross, but we abuse the identify routine to perform one-time
1111  * SYSINIT() style initialization for the driver.
1112  */
1113 static void
1114 acpi_pci_link_init(struct acpi_pci_link_softc *sc)
1115 {
1116 	ACPI_BUFFER buf;
1117 
1118 	/*
1119 	 * If the SCI is an ISA IRQ, add it to the bitmask of known good
1120 	 * ISA IRQs.
1121 	 *
1122 	 * XXX: If we are using the APIC, the SCI might have been
1123 	 * rerouted to an APIC pin in which case this is invalid.  However,
1124 	 * if we are using the APIC, we also shouldn't be having any PCI
1125 	 * interrupts routed via ISA IRQs, so this is probably ok.
1126 	 */
1127 	if (AcpiGbl_FADT.SciInterrupt < NUM_ISA_INTERRUPTS)
1128 		pci_link_bios_isa_irqs |= (1 << AcpiGbl_FADT.SciInterrupt);
1129 
1130 	buf.Length = sizeof (sc->pl_name);
1131 	buf.Pointer = sc->pl_name;
1132 
1133 	if (ACPI_FAILURE(AcpiGetName(sc->pl_handle, ACPI_SINGLE_NAME, &buf)))
1134 		snprintf(sc->pl_name, sizeof (sc->pl_name), "%s",
1135 		    "ACPI link device");
1136 
1137 	acpi_pci_link_attach(sc);
1138 }
1139 
1140 void *
1141 acpi_pci_link_devbyhandle(ACPI_HANDLE handle)
1142 {
1143 	struct acpi_pci_link_softc *sc;
1144 
1145 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
1146 		if (sc->pl_handle == handle)
1147 			return sc;
1148 	}
1149 
1150 	sc = malloc(sizeof (*sc), M_PCI_LINK, M_NOWAIT|M_ZERO);
1151 	if (sc == NULL)
1152 		return NULL;
1153 
1154 	sc->pl_handle = handle;
1155 
1156 	acpi_pci_link_init(sc);
1157 
1158 	TAILQ_INSERT_TAIL(&acpi_pci_linkdevs, sc, pl_list);
1159 
1160 	return (void *)sc;
1161 }
1162 
1163 void
1164 acpi_pci_link_resume(void)
1165 {
1166 	struct acpi_pci_link_softc *sc;
1167 	ACPI_BUFFER srsbuf;
1168 
1169 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
1170 		ACPI_SERIAL_BEGIN(pci_link);
1171 		if (ACPI_SUCCESS(acpi_pci_link_srs(sc, &srsbuf)))
1172 			ACPI_FREE(srsbuf.Pointer);
1173 		ACPI_SERIAL_END(pci_link);
1174 	}
1175 }
1176 
1177 ACPI_HANDLE
1178 acpi_pci_link_handle(void *v)
1179 {
1180 	struct acpi_pci_link_softc *sc = v;
1181 
1182 	return sc->pl_handle;
1183 }
1184 
1185 char *
1186 acpi_pci_link_name(void *v)
1187 {
1188 	struct acpi_pci_link_softc *sc = v;
1189 
1190 	return sc->pl_name;
1191 }
1192 
1193 
1194 /*
1195  * Append an ACPI_RESOURCE to an ACPI_BUFFER.
1196  *
1197  * Given a pointer to an ACPI_RESOURCE structure, expand the ACPI_BUFFER
1198  * provided to contain it.  If the ACPI_BUFFER is empty, allocate a sensible
1199  * backing block.  If the ACPI_RESOURCE is NULL, return an empty set of
1200  * resources.
1201  */
1202 #define ACPI_INITIAL_RESOURCE_BUFFER_SIZE	512
1203 
1204 static ACPI_STATUS
1205 acpi_AppendBufferResource(ACPI_BUFFER *buf, ACPI_RESOURCE *res)
1206 {
1207 	ACPI_RESOURCE	*rp;
1208 	void		*newp;
1209 
1210 	/* Initialise the buffer if necessary. */
1211 	if (buf->Pointer == NULL) {
1212 	buf->Length = ACPI_INITIAL_RESOURCE_BUFFER_SIZE;
1213 	if ((buf->Pointer = ACPI_ALLOCATE(buf->Length)) == NULL)
1214 		return (AE_NO_MEMORY);
1215 	rp = (ACPI_RESOURCE *)buf->Pointer;
1216 	rp->Type =  ACPI_RESOURCE_TYPE_END_TAG;
1217 	rp->Length = 0;
1218 	}
1219 
1220 	if (res == NULL)
1221 		return (AE_OK);
1222 
1223 	/*
1224 	 * Scan the current buffer looking for the terminator.
1225 	 * This will either find the terminator or hit the end
1226 	 * of the buffer and return an error.
1227 	 */
1228 	rp = (ACPI_RESOURCE *)buf->Pointer;
1229 	for (;;) {
1230 		/* Range check, don't go outside the buffer */
1231 		if (rp >= (ACPI_RESOURCE *)((u_int8_t *)buf->Pointer +
1232 		    buf->Length))
1233 			return (AE_BAD_PARAMETER);
1234 		if (rp->Type ==  ACPI_RESOURCE_TYPE_END_TAG || rp->Length == 0)
1235 			break;
1236 		rp = ACPI_NEXT_RESOURCE(rp);
1237 	}
1238 
1239 	/*
1240 	 * Check the size of the buffer and expand if required.
1241 	 *
1242 	 * Required size is:
1243 	 *	size of existing resources before terminator +
1244 	 *	size of new resource and header +
1245 	 * 	size of terminator.
1246 	 *
1247 	 * Note that this loop should really only run once, unless
1248 	 * for some reason we are stuffing a *really* huge resource.
1249 	 */
1250 	while ((((u_int8_t *)rp - (u_int8_t *)buf->Pointer) +
1251 	    res->Length + ACPI_RS_SIZE_NO_DATA +
1252 	    ACPI_RS_SIZE_MIN) >= buf->Length) {
1253 		if ((newp = ACPI_ALLOCATE(buf->Length * 2)) == NULL)
1254 			return (AE_NO_MEMORY);
1255 		memcpy(newp, buf->Pointer, buf->Length);
1256 		rp = (ACPI_RESOURCE *)((u_int8_t *)newp +
1257 		   ((u_int8_t *)rp - (u_int8_t *)buf->Pointer));
1258 		ACPI_FREE(buf->Pointer);
1259 		buf->Pointer = newp;
1260 		buf->Length += buf->Length;
1261 	}
1262 
1263 	/* Insert the new resource. */
1264 	memcpy(rp, res, res->Length + ACPI_RS_SIZE_NO_DATA);
1265 
1266 	/* And add the terminator. */
1267 	rp = ACPI_NEXT_RESOURCE(rp);
1268 	rp->Type =  ACPI_RESOURCE_TYPE_END_TAG;
1269 	rp->Length = 0;
1270 
1271 	return (AE_OK);
1272 }
1273