xref: /freebsd/sys/dev/acpica/acpi_pci_link.c (revision 60d3d21057533e7a336f8504806f0faf41814b02)
1 /*-
2  * Copyright (c) 2002 Mitsuru IWASAKI <iwasaki@jp.freebsd.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "opt_acpi.h"
31 #include <sys/param.h>
32 #include <sys/bus.h>
33 #include <sys/kernel.h>
34 #include <sys/limits.h>
35 #include <sys/malloc.h>
36 #include <sys/module.h>
37 
38 #include <contrib/dev/acpica/acpi.h>
39 #include <dev/acpica/acpivar.h>
40 #include <dev/acpica/acpi_pcibvar.h>
41 
42 #include <machine/pci_cfgreg.h>
43 #include <dev/pci/pcireg.h>
44 #include <dev/pci/pcivar.h>
45 #include "pcib_if.h"
46 
47 /* Hooks for the ACPI CA debugging infrastructure. */
48 #define _COMPONENT	ACPI_BUS
49 ACPI_MODULE_NAME("PCI_LINK")
50 
51 ACPI_SERIAL_DECL(pci_link, "ACPI PCI link");
52 
53 #define NUM_ISA_INTERRUPTS	16
54 #define NUM_ACPI_INTERRUPTS	256
55 
56 /*
57  * An ACPI PCI link device may contain multiple links.  Each link has its
58  * own ACPI resource.  _PRT entries specify which link is being used via
59  * the Source Index.
60  *
61  * XXX: A note about Source Indices and DPFs:  Currently we assume that
62  * the DPF start and end tags are not counted towards the index that
63  * Source Index corresponds to.  Also, we assume that when DPFs are in use
64  * they various sets overlap in terms of Indices.  Here's an example
65  * resource list indicating these assumptions:
66  *
67  * Resource		Index
68  * --------		-----
69  * I/O Port		0
70  * Start DPF		-
71  * IRQ			1
72  * MemIO		2
73  * Start DPF		-
74  * IRQ			1
75  * MemIO		2
76  * End DPF		-
77  * DMA Channel		3
78  *
79  * The XXX is because I'm not sure if this is a valid assumption to make.
80  */
81 
82 /* States during DPF processing. */
83 #define	DPF_OUTSIDE	0
84 #define	DPF_FIRST	1
85 #define	DPF_IGNORE	2
86 
87 struct link;
88 
89 struct acpi_pci_link_softc {
90 	int	pl_num_links;
91 	int	pl_crs_bad;
92 	struct link *pl_links;
93 	device_t pl_dev;
94 };
95 
96 struct link {
97 	struct acpi_pci_link_softc *l_sc;
98 	uint8_t	l_bios_irq;
99 	uint8_t	l_irq;
100 	uint8_t	l_initial_irq;
101 	int	l_res_index;
102 	int	l_num_irqs;
103 	int	*l_irqs;
104 	int	l_references;
105 	int	l_routed:1;
106 	int	l_isa_irq:1;
107 	ACPI_RESOURCE l_prs_template;
108 };
109 
110 struct link_count_request {
111 	int	in_dpf;
112 	int	count;
113 };
114 
115 struct link_res_request {
116 	struct acpi_pci_link_softc *sc;
117 	int	in_dpf;
118 	int	res_index;
119 	int	link_index;
120 };
121 
122 MALLOC_DEFINE(M_PCI_LINK, "pci_link", "ACPI PCI Link structures");
123 
124 static int pci_link_interrupt_weights[NUM_ACPI_INTERRUPTS];
125 static int pci_link_bios_isa_irqs;
126 
127 static char *pci_link_ids[] = { "PNP0C0F", NULL };
128 
129 /*
130  * Fetch the short name associated with an ACPI handle and save it in the
131  * passed in buffer.
132  */
133 static ACPI_STATUS
134 acpi_short_name(ACPI_HANDLE handle, char *buffer, size_t buflen)
135 {
136 	ACPI_BUFFER buf;
137 
138 	buf.Length = buflen;
139 	buf.Pointer = buffer;
140 	return (AcpiGetName(handle, ACPI_SINGLE_NAME, &buf));
141 }
142 
143 static int
144 acpi_pci_link_probe(device_t dev)
145 {
146 	char descr[28], name[12];
147 
148 	/*
149 	 * We explicitly do not check _STA since not all systems set it to
150 	 * sensible values.
151 	 */
152 	if (acpi_disabled("pci_link") ||
153 	    ACPI_ID_PROBE(device_get_parent(dev), dev, pci_link_ids) == NULL)
154 		return (ENXIO);
155 
156 	if (ACPI_SUCCESS(acpi_short_name(acpi_get_handle(dev), name,
157 	    sizeof(name)))) {
158 		snprintf(descr, sizeof(descr), "ACPI PCI Link %s", name);
159 		device_set_desc_copy(dev, descr);
160 	} else
161 		device_set_desc(dev, "ACPI PCI Link");
162 	return (0);
163 }
164 
165 static ACPI_STATUS
166 acpi_count_irq_resources(ACPI_RESOURCE *res, void *context)
167 {
168 	struct link_count_request *req;
169 
170 	req = (struct link_count_request *)context;
171 	switch (res->Type) {
172 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
173 		switch (req->in_dpf) {
174 		case DPF_OUTSIDE:
175 			/* We've started the first DPF. */
176 			req->in_dpf = DPF_FIRST;
177 			break;
178 		case DPF_FIRST:
179 			/* We've started the second DPF. */
180 			req->in_dpf = DPF_IGNORE;
181 			break;
182 		}
183 		break;
184 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
185 		/* We are finished with DPF parsing. */
186 		KASSERT(req->in_dpf != DPF_OUTSIDE,
187 		    ("%s: end dpf when not parsing a dpf", __func__));
188 		req->in_dpf = DPF_OUTSIDE;
189 		break;
190 	case ACPI_RESOURCE_TYPE_IRQ:
191 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
192 		/*
193 		 * Don't count resources if we are in a DPF set that we are
194 		 * ignoring.
195 		 */
196 		if (req->in_dpf != DPF_IGNORE)
197 			req->count++;
198 	}
199 	return (AE_OK);
200 }
201 
202 static ACPI_STATUS
203 link_add_crs(ACPI_RESOURCE *res, void *context)
204 {
205 	struct link_res_request *req;
206 	struct link *link;
207 
208 	ACPI_SERIAL_ASSERT(pci_link);
209 	req = (struct link_res_request *)context;
210 	switch (res->Type) {
211 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
212 		switch (req->in_dpf) {
213 		case DPF_OUTSIDE:
214 			/* We've started the first DPF. */
215 			req->in_dpf = DPF_FIRST;
216 			break;
217 		case DPF_FIRST:
218 			/* We've started the second DPF. */
219 			panic(
220 		"%s: Multiple dependent functions within a current resource",
221 			    __func__);
222 			break;
223 		}
224 		break;
225 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
226 		/* We are finished with DPF parsing. */
227 		KASSERT(req->in_dpf != DPF_OUTSIDE,
228 		    ("%s: end dpf when not parsing a dpf", __func__));
229 		req->in_dpf = DPF_OUTSIDE;
230 		break;
231 	case ACPI_RESOURCE_TYPE_IRQ:
232 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
233 		KASSERT(req->link_index < req->sc->pl_num_links,
234 		    ("%s: array boundary violation", __func__));
235 		link = &req->sc->pl_links[req->link_index];
236 		link->l_res_index = req->res_index;
237 		req->link_index++;
238 		req->res_index++;
239 
240 		/*
241 		 * Only use the current value if there's one IRQ.  Some
242 		 * systems return multiple IRQs (which is nonsense for _CRS)
243 		 * when the link hasn't been programmed.
244 		 */
245 		if (res->Type == ACPI_RESOURCE_TYPE_IRQ) {
246 			if (res->Data.Irq.InterruptCount == 1)
247 				link->l_irq = res->Data.Irq.Interrupts[0];
248 		} else if (res->Data.ExtendedIrq.InterruptCount == 1)
249 			link->l_irq = res->Data.ExtendedIrq.Interrupts[0];
250 
251 		/*
252 		 * An IRQ of zero means that the link isn't routed.
253 		 */
254 		if (link->l_irq == 0)
255 			link->l_irq = PCI_INVALID_IRQ;
256 		break;
257 	default:
258 		req->res_index++;
259 	}
260 	return (AE_OK);
261 }
262 
263 /*
264  * Populate the set of possible IRQs for each device.
265  */
266 static ACPI_STATUS
267 link_add_prs(ACPI_RESOURCE *res, void *context)
268 {
269 	struct link_res_request *req;
270 	struct link *link;
271 	UINT8 *irqs = NULL;
272 	UINT32 *ext_irqs = NULL;
273 	int i, is_ext_irq = 1;
274 
275 	ACPI_SERIAL_ASSERT(pci_link);
276 	req = (struct link_res_request *)context;
277 	switch (res->Type) {
278 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
279 		switch (req->in_dpf) {
280 		case DPF_OUTSIDE:
281 			/* We've started the first DPF. */
282 			req->in_dpf = DPF_FIRST;
283 			break;
284 		case DPF_FIRST:
285 			/* We've started the second DPF. */
286 			req->in_dpf = DPF_IGNORE;
287 			break;
288 		}
289 		break;
290 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
291 		/* We are finished with DPF parsing. */
292 		KASSERT(req->in_dpf != DPF_OUTSIDE,
293 		    ("%s: end dpf when not parsing a dpf", __func__));
294 		req->in_dpf = DPF_OUTSIDE;
295 		break;
296 	case ACPI_RESOURCE_TYPE_IRQ:
297 		is_ext_irq = 0;
298 		/* fall through */
299 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
300 		/*
301 		 * Don't parse resources if we are in a DPF set that we are
302 		 * ignoring.
303 		 */
304 		if (req->in_dpf == DPF_IGNORE)
305 			break;
306 
307 		KASSERT(req->link_index < req->sc->pl_num_links,
308 		    ("%s: array boundary violation", __func__));
309 		link = &req->sc->pl_links[req->link_index];
310 		if (link->l_res_index == -1) {
311 			KASSERT(req->sc->pl_crs_bad,
312 			    ("res_index should be set"));
313 			link->l_res_index = req->res_index;
314 		}
315 		req->link_index++;
316 		req->res_index++;
317 
318 		/*
319 		 * Stash a copy of the resource for later use when doing
320 		 * _SRS.
321 		 */
322 		bcopy(res, &link->l_prs_template, sizeof(ACPI_RESOURCE));
323 		if (is_ext_irq) {
324 			link->l_num_irqs =
325 			    res->Data.ExtendedIrq.InterruptCount;
326 			ext_irqs = res->Data.ExtendedIrq.Interrupts;
327 		} else {
328 			link->l_num_irqs = res->Data.Irq.InterruptCount;
329 			irqs = res->Data.Irq.Interrupts;
330 		}
331 		if (link->l_num_irqs == 0)
332 			break;
333 
334 		/*
335 		 * Save a list of the valid IRQs.  Also, if all of the
336 		 * valid IRQs are ISA IRQs, then mark this link as
337 		 * routed via an ISA interrupt.
338 		 */
339 		link->l_isa_irq = TRUE;
340 		link->l_irqs = malloc(sizeof(int) * link->l_num_irqs,
341 		    M_PCI_LINK, M_WAITOK | M_ZERO);
342 		for (i = 0; i < link->l_num_irqs; i++) {
343 			if (is_ext_irq) {
344 				link->l_irqs[i] = ext_irqs[i];
345 				if (ext_irqs[i] >= NUM_ISA_INTERRUPTS)
346 					link->l_isa_irq = FALSE;
347 			} else {
348 				link->l_irqs[i] = irqs[i];
349 				if (irqs[i] >= NUM_ISA_INTERRUPTS)
350 					link->l_isa_irq = FALSE;
351 			}
352 		}
353 		break;
354 	default:
355 		if (req->in_dpf == DPF_IGNORE)
356 			break;
357 		if (req->sc->pl_crs_bad)
358 			device_printf(req->sc->pl_dev,
359 		    "Warning: possible resource %d will be lost during _SRS\n",
360 			    req->res_index);
361 		req->res_index++;
362 	}
363 	return (AE_OK);
364 }
365 
366 static int
367 link_valid_irq(struct link *link, int irq)
368 {
369 	int i;
370 
371 	ACPI_SERIAL_ASSERT(pci_link);
372 
373 	/* Invalid interrupts are never valid. */
374 	if (!PCI_INTERRUPT_VALID(irq))
375 		return (FALSE);
376 
377 	/* Any interrupt in the list of possible interrupts is valid. */
378 	for (i = 0; i < link->l_num_irqs; i++)
379 		if (link->l_irqs[i] == irq)
380 			 return (TRUE);
381 
382 	/*
383 	 * For links routed via an ISA interrupt, if the SCI is routed via
384 	 * an ISA interrupt, the SCI is always treated as a valid IRQ.
385 	 */
386 	if (link->l_isa_irq && AcpiGbl_FADT->SciInt == irq &&
387 	    irq < NUM_ISA_INTERRUPTS)
388 		return (TRUE);
389 
390 	/* If the interrupt wasn't found in the list it is not valid. */
391 	return (FALSE);
392 }
393 
394 static void
395 acpi_pci_link_dump(struct acpi_pci_link_softc *sc)
396 {
397 	struct link *link;
398 	int i, j;
399 
400 	ACPI_SERIAL_ASSERT(pci_link);
401 	printf("Index  IRQ  Rtd  Ref  IRQs\n");
402 	for (i = 0; i < sc->pl_num_links; i++) {
403 		link = &sc->pl_links[i];
404 		printf("%5d  %3d   %c   %3d ", i, link->l_irq,
405 		    link->l_routed ? 'Y' : 'N',  link->l_references);
406 		if (link->l_num_irqs == 0)
407 			printf(" none");
408 		else for (j = 0; j < link->l_num_irqs; j++)
409 			printf(" %d", link->l_irqs[j]);
410 		printf("\n");
411 	}
412 }
413 
414 static int
415 acpi_pci_link_attach(device_t dev)
416 {
417 	struct acpi_pci_link_softc *sc;
418 	struct link_count_request creq;
419 	struct link_res_request rreq;
420 	ACPI_STATUS status;
421 	int i;
422 
423 	sc = device_get_softc(dev);
424 	sc->pl_dev = dev;
425 	ACPI_SERIAL_BEGIN(pci_link);
426 
427 	/*
428 	 * Count the number of current resources so we know how big of
429 	 * a link array to allocate.  On some systems, _CRS is broken,
430 	 * so for those systems try to derive the count from _PRS instead.
431 	 */
432 	creq.in_dpf = DPF_OUTSIDE;
433 	creq.count = 0;
434 	status = AcpiWalkResources(acpi_get_handle(dev), "_CRS",
435 	    acpi_count_irq_resources, &creq);
436 	sc->pl_crs_bad = ACPI_FAILURE(status);
437 	if (sc->pl_crs_bad) {
438 		creq.in_dpf = DPF_OUTSIDE;
439 		creq.count = 0;
440 		status = AcpiWalkResources(acpi_get_handle(dev), "_PRS",
441 		    acpi_count_irq_resources, &creq);
442 		if (ACPI_FAILURE(status)) {
443 			device_printf(dev,
444 			    "Unable to parse _CRS or _PRS: %s\n",
445 			    AcpiFormatException(status));
446 			ACPI_SERIAL_END(pci_link);
447 			return (ENXIO);
448 		}
449 	}
450 	sc->pl_num_links = creq.count;
451 	if (creq.count == 0)
452 		return (0);
453 	sc->pl_links = malloc(sizeof(struct link) * sc->pl_num_links,
454 	    M_PCI_LINK, M_WAITOK | M_ZERO);
455 
456 	/* Initialize the child links. */
457 	for (i = 0; i < sc->pl_num_links; i++) {
458 		sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
459 		sc->pl_links[i].l_bios_irq = PCI_INVALID_IRQ;
460 		sc->pl_links[i].l_sc = sc;
461 		sc->pl_links[i].l_isa_irq = FALSE;
462 		sc->pl_links[i].l_res_index = -1;
463 	}
464 
465 	/* Try to read the current settings from _CRS if it is valid. */
466 	if (!sc->pl_crs_bad) {
467 		rreq.in_dpf = DPF_OUTSIDE;
468 		rreq.link_index = 0;
469 		rreq.res_index = 0;
470 		rreq.sc = sc;
471 		status = AcpiWalkResources(acpi_get_handle(dev), "_CRS",
472 		    link_add_crs, &rreq);
473 		if (ACPI_FAILURE(status)) {
474 			device_printf(dev, "Unable to parse _CRS: %s\n",
475 			    AcpiFormatException(status));
476 			goto fail;
477 		}
478 	}
479 
480 	/*
481 	 * Try to read the possible settings from _PRS.  Note that if the
482 	 * _CRS is toast, we depend on having a working _PRS.  However, if
483 	 * _CRS works, then it is ok for _PRS to be missing.
484 	 */
485 	rreq.in_dpf = DPF_OUTSIDE;
486 	rreq.link_index = 0;
487 	rreq.res_index = 0;
488 	rreq.sc = sc;
489 	status = AcpiWalkResources(acpi_get_handle(dev), "_PRS",
490 	    link_add_prs, &rreq);
491 	if (ACPI_FAILURE(status) &&
492 	    (status != AE_NOT_FOUND || sc->pl_crs_bad)) {
493 		device_printf(dev, "Unable to parse _PRS: %s\n",
494 		    AcpiFormatException(status));
495 		goto fail;
496 	}
497 	if (bootverbose) {
498 		device_printf(dev, "Links after initial probe:\n");
499 		acpi_pci_link_dump(sc);
500 	}
501 
502 	/* Verify initial IRQs if we have _PRS. */
503 	if (status != AE_NOT_FOUND)
504 		for (i = 0; i < sc->pl_num_links; i++)
505 			if (!link_valid_irq(&sc->pl_links[i],
506 			    sc->pl_links[i].l_irq))
507 				sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
508 	if (bootverbose) {
509 		device_printf(dev, "Links after initial validation:\n");
510 		acpi_pci_link_dump(sc);
511 	}
512 
513 	/* Save initial IRQs. */
514 	for (i = 0; i < sc->pl_num_links; i++)
515 		sc->pl_links[i].l_initial_irq = sc->pl_links[i].l_irq;
516 
517 	/*
518 	 * Try to disable this link.  If successful, set the current IRQ to
519 	 * zero and flags to indicate this link is not routed.  If we can't
520 	 * run _DIS (i.e., the method doesn't exist), assume the initial
521 	 * IRQ was routed by the BIOS.
522 	 */
523 	if (ACPI_SUCCESS(AcpiEvaluateObject(acpi_get_handle(dev), "_DIS", NULL,
524 	    NULL)))
525 		for (i = 0; i < sc->pl_num_links; i++)
526 			sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
527 	else
528 		for (i = 0; i < sc->pl_num_links; i++)
529 			if (PCI_INTERRUPT_VALID(sc->pl_links[i].l_irq))
530 				sc->pl_links[i].l_routed = TRUE;
531 	if (bootverbose) {
532 		device_printf(dev, "Links after disable:\n");
533 		acpi_pci_link_dump(sc);
534 	}
535 	ACPI_SERIAL_END(pci_link);
536 	return (0);
537 fail:
538 	ACPI_SERIAL_END(pci_link);
539 	for (i = 0; i < sc->pl_num_links; i++)
540 		if (sc->pl_links[i].l_irqs != NULL)
541 			free(sc->pl_links[i].l_irqs, M_PCI_LINK);
542 	free(sc->pl_links, M_PCI_LINK);
543 	return (ENXIO);
544 }
545 
546 /* XXX: Note that this is identical to pci_pir_search_irq(). */
547 static uint8_t
548 acpi_pci_link_search_irq(int bus, int device, int pin)
549 {
550 	uint32_t value;
551 	uint8_t func, maxfunc;
552 
553 	/* See if we have a valid device at function 0. */
554 	value = pci_cfgregread(bus, device, 0, PCIR_HDRTYPE, 1);
555 	if ((value & PCIM_HDRTYPE) > PCI_MAXHDRTYPE)
556 		return (PCI_INVALID_IRQ);
557 	if (value & PCIM_MFDEV)
558 		maxfunc = PCI_FUNCMAX;
559 	else
560 		maxfunc = 0;
561 
562 	/* Scan all possible functions at this device. */
563 	for (func = 0; func <= maxfunc; func++) {
564 		value = pci_cfgregread(bus, device, func, PCIR_DEVVENDOR, 4);
565 		if (value == 0xffffffff)
566 			continue;
567 		value = pci_cfgregread(bus, device, func, PCIR_INTPIN, 1);
568 
569 		/*
570 		 * See if it uses the pin in question.  Note that the passed
571 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
572 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
573 		 */
574 		if (value != pin + 1)
575 			continue;
576 		value = pci_cfgregread(bus, device, func, PCIR_INTLINE, 1);
577 		if (bootverbose)
578 			printf(
579 		"ACPI: Found matching pin for %d.%d.INT%c at func %d: %d\n",
580 			    bus, device, pin + 'A', func, value);
581 		if (value != PCI_INVALID_IRQ)
582 			return (value);
583 	}
584 	return (PCI_INVALID_IRQ);
585 }
586 
587 /*
588  * Find the link structure that corresponds to the resource index passed in
589  * via 'source_index'.
590  */
591 static struct link *
592 acpi_pci_link_lookup(device_t dev, int source_index)
593 {
594 	struct acpi_pci_link_softc *sc;
595 	int i;
596 
597 	ACPI_SERIAL_ASSERT(pci_link);
598 	sc = device_get_softc(dev);
599 	for (i = 0; i < sc->pl_num_links; i++)
600 		if (sc->pl_links[i].l_res_index == source_index)
601 			return (&sc->pl_links[i]);
602 	return (NULL);
603 }
604 
605 void
606 acpi_pci_link_add_reference(device_t dev, int index, device_t pcib, int slot,
607     int pin)
608 {
609 	struct link *link;
610 	uint8_t bios_irq;
611 
612 	/* Bump the reference count. */
613 	ACPI_SERIAL_BEGIN(pci_link);
614 	link = acpi_pci_link_lookup(dev, index);
615 	if (link == NULL)
616 		panic("%s: apparently invalid index %d", __func__, index);
617 	link->l_references++;
618 	if (link->l_routed)
619 		pci_link_interrupt_weights[link->l_irq]++;
620 
621 	/* Try to find a BIOS IRQ setting from any matching devices. */
622 	bios_irq = acpi_pci_link_search_irq(pcib_get_bus(pcib), slot, pin);
623 	if (!PCI_INTERRUPT_VALID(bios_irq)) {
624 		ACPI_SERIAL_END(pci_link);
625 		return;
626 	}
627 
628 	/* Validate the BIOS IRQ. */
629 	if (!link_valid_irq(link, bios_irq)) {
630 		device_printf(dev, "BIOS IRQ %u for %d.%d.INT%c is invalid\n",
631 		    bios_irq, pcib_get_bus(pcib), slot, pin + 'A');
632 	} else if (!PCI_INTERRUPT_VALID(link->l_bios_irq)) {
633 		link->l_bios_irq = bios_irq;
634 		if (bios_irq < NUM_ISA_INTERRUPTS)
635 			pci_link_bios_isa_irqs |= (1 << bios_irq);
636 		if (bios_irq != link->l_initial_irq &&
637 		    PCI_INTERRUPT_VALID(link->l_initial_irq))
638 			device_printf(dev,
639 			    "BIOS IRQ %u does not match initial IRQ %u\n",
640 			    bios_irq, link->l_initial_irq);
641 	} else if (bios_irq != link->l_bios_irq)
642 		device_printf(dev,
643 	    "BIOS IRQ %u for %d.%d.INT%c does not match previous BIOS IRQ %u\n",
644 		    bios_irq, pcib_get_bus(pcib), slot, pin + 'A',
645 		    link->l_bios_irq);
646 	ACPI_SERIAL_END(pci_link);
647 }
648 
649 static ACPI_STATUS
650 acpi_pci_link_srs_from_crs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
651 {
652 	ACPI_RESOURCE *resource, *end, newres, *resptr;
653 	ACPI_BUFFER crsbuf;
654 	ACPI_STATUS status;
655 	struct link *link;
656 	int i, in_dpf;
657 
658 	/* Fetch the _CRS. */
659 	ACPI_SERIAL_ASSERT(pci_link);
660 	crsbuf.Pointer = NULL;
661 	crsbuf.Length = ACPI_ALLOCATE_BUFFER;
662 	status = AcpiGetCurrentResources(acpi_get_handle(sc->pl_dev), &crsbuf);
663 	if (ACPI_SUCCESS(status) && crsbuf.Pointer == NULL)
664 		status = AE_NO_MEMORY;
665 	if (ACPI_FAILURE(status)) {
666 		if (bootverbose)
667 			device_printf(sc->pl_dev,
668 			    "Unable to fetch current resources: %s\n",
669 			    AcpiFormatException(status));
670 		return (status);
671 	}
672 
673 	/* Fill in IRQ resources via link structures. */
674 	srsbuf->Pointer = NULL;
675 	link = sc->pl_links;
676 	i = 0;
677 	in_dpf = DPF_OUTSIDE;
678 	resource = (ACPI_RESOURCE *)crsbuf.Pointer;
679 	end = (ACPI_RESOURCE *)((char *)crsbuf.Pointer + crsbuf.Length);
680 	for (;;) {
681 		switch (resource->Type) {
682 		case ACPI_RESOURCE_TYPE_START_DEPENDENT:
683 			switch (in_dpf) {
684 			case DPF_OUTSIDE:
685 				/* We've started the first DPF. */
686 				in_dpf = DPF_FIRST;
687 				break;
688 			case DPF_FIRST:
689 				/* We've started the second DPF. */
690 				panic(
691 		"%s: Multiple dependent functions within a current resource",
692 				    __func__);
693 				break;
694 			}
695 			resptr = NULL;
696 			break;
697 		case ACPI_RESOURCE_TYPE_END_DEPENDENT:
698 			/* We are finished with DPF parsing. */
699 			KASSERT(in_dpf != DPF_OUTSIDE,
700 			    ("%s: end dpf when not parsing a dpf", __func__));
701 			in_dpf = DPF_OUTSIDE;
702 			resptr = NULL;
703 			break;
704 		case ACPI_RESOURCE_TYPE_IRQ:
705 			MPASS(i < sc->pl_num_links);
706 			MPASS(link->l_prs_template.Type == ACPI_RESOURCE_TYPE_IRQ);
707 			newres = link->l_prs_template;
708 			resptr = &newres;
709 			resptr->Data.Irq.InterruptCount = 1;
710 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
711 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS,
712 		("%s: can't put non-ISA IRQ %d in legacy IRQ resource type",
713 				    __func__, link->l_irq));
714 				resptr->Data.Irq.Interrupts[0] = link->l_irq;
715 			} else
716 				resptr->Data.Irq.Interrupts[0] = 0;
717 			link++;
718 			i++;
719 			break;
720 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
721 			MPASS(i < sc->pl_num_links);
722 			MPASS(link->l_prs_template.Type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ);
723 			newres = link->l_prs_template;
724 			resptr = &newres;
725 			resptr->Data.ExtendedIrq.InterruptCount = 1;
726 			if (PCI_INTERRUPT_VALID(link->l_irq))
727 				resptr->Data.ExtendedIrq.Interrupts[0] =
728 				    link->l_irq;
729 			else
730 				resptr->Data.ExtendedIrq.Interrupts[0] = 0;
731 			link++;
732 			i++;
733 			break;
734 		default:
735 			resptr = resource;
736 		}
737 		if (resptr != NULL) {
738 			status = acpi_AppendBufferResource(srsbuf, resptr);
739 			if (ACPI_FAILURE(status)) {
740 				device_printf(sc->pl_dev,
741 				    "Unable to build resources: %s\n",
742 				    AcpiFormatException(status));
743 				if (srsbuf->Pointer != NULL)
744 					AcpiOsFree(srsbuf->Pointer);
745 				AcpiOsFree(crsbuf.Pointer);
746 				return (status);
747 			}
748 		}
749 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
750 			break;
751 		resource = ACPI_NEXT_RESOURCE(resource);
752 		if (resource >= end)
753 			break;
754 	}
755 	AcpiOsFree(crsbuf.Pointer);
756 	return (AE_OK);
757 }
758 
759 static ACPI_STATUS
760 acpi_pci_link_srs_from_links(struct acpi_pci_link_softc *sc,
761     ACPI_BUFFER *srsbuf)
762 {
763 	ACPI_RESOURCE newres;
764 	ACPI_STATUS status;
765 	struct link *link;
766 	int i;
767 
768 	/* Start off with an empty buffer. */
769 	srsbuf->Pointer = NULL;
770 	link = sc->pl_links;
771 	for (i = 0; i < sc->pl_num_links; i++) {
772 
773 		/* Add a new IRQ resource from each link. */
774 		link = &sc->pl_links[i];
775 		newres = link->l_prs_template;
776 		if (newres.Type == ACPI_RESOURCE_TYPE_IRQ) {
777 
778 			/* Build an IRQ resource. */
779 			newres.Data.Irq.InterruptCount = 1;
780 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
781 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS,
782 		("%s: can't put non-ISA IRQ %d in legacy IRQ resource type",
783 				    __func__, link->l_irq));
784 				newres.Data.Irq.Interrupts[0] = link->l_irq;
785 			} else
786 				newres.Data.Irq.Interrupts[0] = 0;
787 		} else {
788 
789 			/* Build an ExtIRQ resuorce. */
790 			newres.Data.ExtendedIrq.InterruptCount = 1;
791 			if (PCI_INTERRUPT_VALID(link->l_irq))
792 				newres.Data.ExtendedIrq.Interrupts[0] =
793 				    link->l_irq;
794 			else
795 				newres.Data.ExtendedIrq.Interrupts[0] = 0;
796 		}
797 
798 		/* Add the new resource to the end of the _SRS buffer. */
799 		status = acpi_AppendBufferResource(srsbuf, &newres);
800 		if (ACPI_FAILURE(status)) {
801 			device_printf(sc->pl_dev,
802 			    "Unable to build resources: %s\n",
803 			    AcpiFormatException(status));
804 			if (srsbuf->Pointer != NULL)
805 				AcpiOsFree(srsbuf->Pointer);
806 			return (status);
807 		}
808 	}
809 	return (AE_OK);
810 }
811 
812 static ACPI_STATUS
813 acpi_pci_link_route_irqs(device_t dev)
814 {
815 	struct acpi_pci_link_softc *sc;
816 	ACPI_RESOURCE *resource, *end;
817 	ACPI_BUFFER srsbuf;
818 	ACPI_STATUS status;
819 	struct link *link;
820 	int i;
821 
822 	ACPI_SERIAL_ASSERT(pci_link);
823 	sc = device_get_softc(dev);
824 	if (sc->pl_crs_bad)
825 		status = acpi_pci_link_srs_from_links(sc, &srsbuf);
826 	else
827 		status = acpi_pci_link_srs_from_crs(sc, &srsbuf);
828 
829 	/* Write out new resources via _SRS. */
830 	status = AcpiSetCurrentResources(acpi_get_handle(dev), &srsbuf);
831 	if (ACPI_FAILURE(status)) {
832 		device_printf(dev, "Unable to route IRQs: %s\n",
833 		    AcpiFormatException(status));
834 		AcpiOsFree(srsbuf.Pointer);
835 		return (status);
836 	}
837 
838 	/*
839 	 * Perform acpi_config_intr() on each IRQ resource if it was just
840 	 * routed for the first time.
841 	 */
842 	link = sc->pl_links;
843 	i = 0;
844 	resource = (ACPI_RESOURCE *)srsbuf.Pointer;
845 	end = (ACPI_RESOURCE *)((char *)srsbuf.Pointer + srsbuf.Length);
846 	for (;;) {
847 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
848 			break;
849 		switch (resource->Type) {
850 		case ACPI_RESOURCE_TYPE_IRQ:
851 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
852 			MPASS(i < sc->pl_num_links);
853 
854 			/*
855 			 * Only configure the interrupt and update the
856 			 * weights if this link has a valid IRQ and was
857 			 * previously unrouted.
858 			 */
859 			if (!link->l_routed &&
860 			    PCI_INTERRUPT_VALID(link->l_irq)) {
861 				link->l_routed = TRUE;
862 				acpi_config_intr(dev, resource);
863 				pci_link_interrupt_weights[link->l_irq] +=
864 				    link->l_references;
865 			}
866 			link++;
867 			i++;
868 			break;
869 		}
870 		resource = ACPI_NEXT_RESOURCE(resource);
871 		if (resource >= end)
872 			break;
873 	}
874 	AcpiOsFree(srsbuf.Pointer);
875 	return (AE_OK);
876 }
877 
878 static int
879 acpi_pci_link_resume(device_t dev)
880 {
881 	ACPI_STATUS status;
882 
883 	ACPI_SERIAL_BEGIN(pci_link);
884 	status = acpi_pci_link_route_irqs(dev);
885 	ACPI_SERIAL_END(pci_link);
886 	if (ACPI_FAILURE(status))
887 		return (ENXIO);
888 	else
889 		return (0);
890 }
891 
892 /*
893  * Pick an IRQ to use for this unrouted link.
894  */
895 static uint8_t
896 acpi_pci_link_choose_irq(device_t dev, struct link *link)
897 {
898 	char tunable_buffer[64], link_name[5];
899 	u_int8_t best_irq, pos_irq;
900 	int best_weight, pos_weight, i;
901 
902 	KASSERT(!link->l_routed, ("%s: link already routed", __func__));
903 	KASSERT(!PCI_INTERRUPT_VALID(link->l_irq),
904 	    ("%s: link already has an IRQ", __func__));
905 
906 	/* Check for a tunable override and use it if it is valid. */
907 	if (ACPI_SUCCESS(acpi_short_name(acpi_get_handle(dev), link_name,
908 	    sizeof(link_name)))) {
909 		snprintf(tunable_buffer, sizeof(tunable_buffer),
910 		    "hw.pci.link.%s.%d.irq", link_name, link->l_res_index);
911 		if (getenv_int(tunable_buffer, &i) &&
912 		    PCI_INTERRUPT_VALID(i) && link_valid_irq(link, i))
913 			return (i);
914 		snprintf(tunable_buffer, sizeof(tunable_buffer),
915 		    "hw.pci.link.%s.irq", link_name);
916 		if (getenv_int(tunable_buffer, &i) &&
917 		    PCI_INTERRUPT_VALID(i) && link_valid_irq(link, i))
918 			return (i);
919 	}
920 
921 	/*
922 	 * If we have a valid BIOS IRQ, use that.  We trust what the BIOS
923 	 * says it routed over what _CRS says the link thinks is routed.
924 	 */
925 	if (PCI_INTERRUPT_VALID(link->l_bios_irq))
926 		return (link->l_bios_irq);
927 
928 	/*
929 	 * If we don't have a BIOS IRQ but do have a valid IRQ from _CRS,
930 	 * then use that.
931 	 */
932 	if (PCI_INTERRUPT_VALID(link->l_initial_irq))
933 		return (link->l_initial_irq);
934 
935 	/*
936 	 * Ok, we have no useful hints, so we have to pick from the
937 	 * possible IRQs.  For ISA IRQs we only use interrupts that
938 	 * have already been used by the BIOS.
939 	 */
940 	best_irq = PCI_INVALID_IRQ;
941 	best_weight = INT_MAX;
942 	for (i = 0; i < link->l_num_irqs; i++) {
943 		pos_irq = link->l_irqs[i];
944 		if (pos_irq < NUM_ISA_INTERRUPTS &&
945 		    (pci_link_bios_isa_irqs & 1 << pos_irq) == 0)
946 			continue;
947 		pos_weight = pci_link_interrupt_weights[pos_irq];
948 		if (pos_weight < best_weight) {
949 			best_weight = pos_weight;
950 			best_irq = pos_irq;
951 		}
952 	}
953 
954 	/*
955 	 * If this is an ISA IRQ, try using the SCI if it is also an ISA
956 	 * interrupt as a fallback.
957 	 */
958 	if (link->l_isa_irq) {
959 		pos_irq = AcpiGbl_FADT->SciInt;
960 		pos_weight = pci_link_interrupt_weights[pos_irq];
961 		if (pos_weight < best_weight) {
962 			best_weight = pos_weight;
963 			best_irq = pos_irq;
964 		}
965 	}
966 
967 	if (PCI_INTERRUPT_VALID(best_irq)) {
968 		if (bootverbose)
969 			device_printf(dev, "Picked IRQ %u with weight %d\n",
970 			    best_irq, best_weight);
971 	} else
972 		device_printf(dev, "Unable to choose an IRQ\n");
973 	return (best_irq);
974 }
975 
976 int
977 acpi_pci_link_route_interrupt(device_t dev, int index)
978 {
979 	struct link *link;
980 
981 	ACPI_SERIAL_BEGIN(pci_link);
982 	link = acpi_pci_link_lookup(dev, index);
983 	if (link == NULL)
984 		panic("%s: apparently invalid index %d", __func__, index);
985 
986 	/*
987 	 * If this link device is already routed to an interrupt, just return
988 	 * the interrupt it is routed to.
989 	 */
990 	if (link->l_routed) {
991 		KASSERT(PCI_INTERRUPT_VALID(link->l_irq),
992 		    ("%s: link is routed but has an invalid IRQ", __func__));
993 		ACPI_SERIAL_END(pci_link);
994 		return (link->l_irq);
995 	}
996 
997 	/* Choose an IRQ if we need one. */
998 	if (!PCI_INTERRUPT_VALID(link->l_irq)) {
999 		link->l_irq = acpi_pci_link_choose_irq(dev, link);
1000 
1001 		/*
1002 		 * Try to route the interrupt we picked.  If it fails, then
1003 		 * assume the interrupt is not routed.
1004 		 */
1005 		if (PCI_INTERRUPT_VALID(link->l_irq)) {
1006 			acpi_pci_link_route_irqs(dev);
1007 			if (!link->l_routed)
1008 				link->l_irq = PCI_INVALID_IRQ;
1009 		}
1010 	}
1011 	ACPI_SERIAL_END(pci_link);
1012 
1013 	return (link->l_irq);
1014 }
1015 
1016 /*
1017  * This is gross, but we abuse the identify routine to perform one-time
1018  * SYSINIT() style initialization for the driver.
1019  */
1020 static void
1021 acpi_pci_link_identify(driver_t *driver, device_t parent)
1022 {
1023 
1024 	/*
1025 	 * If the SCI is an ISA IRQ, add it to the bitmask of known good
1026 	 * ISA IRQs.
1027 	 *
1028 	 * XXX: If we are using the APIC, the SCI might have been
1029 	 * rerouted to an APIC pin in which case this is invalid.  However,
1030 	 * if we are using the APIC, we also shouldn't be having any PCI
1031 	 * interrupts routed via ISA IRQs, so this is probably ok.
1032 	 */
1033 	if (AcpiGbl_FADT->SciInt < NUM_ISA_INTERRUPTS)
1034 		pci_link_bios_isa_irqs |= (1 << AcpiGbl_FADT->SciInt);
1035 }
1036 
1037 static device_method_t acpi_pci_link_methods[] = {
1038 	/* Device interface */
1039 	DEVMETHOD(device_identify,	acpi_pci_link_identify),
1040 	DEVMETHOD(device_probe,		acpi_pci_link_probe),
1041 	DEVMETHOD(device_attach,	acpi_pci_link_attach),
1042 	DEVMETHOD(device_resume,	acpi_pci_link_resume),
1043 
1044 	{0, 0}
1045 };
1046 
1047 static driver_t acpi_pci_link_driver = {
1048 	"pci_link",
1049 	acpi_pci_link_methods,
1050 	sizeof(struct acpi_pci_link_softc),
1051 };
1052 
1053 static devclass_t pci_link_devclass;
1054 
1055 DRIVER_MODULE(acpi_pci_link, acpi, acpi_pci_link_driver, pci_link_devclass, 0,
1056     0);
1057 MODULE_DEPEND(acpi_pci_link, acpi, 1, 1, 1);
1058