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acpi_pci_link.c revision 1.11
      1 /*	$NetBSD: acpi_pci_link.c,v 1.11 2007/12/16 23:11:08 jmcneill Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2002 Mitsuru IWASAKI <iwasaki (at) 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 1.11 2007/12/16 23:11:08 jmcneill Exp $");
     31 
     32 #include "opt_acpi.h"
     33 #include <sys/param.h>
     34 #include <sys/kernel.h>
     35 #include <sys/malloc.h>
     36 #include <sys/queue.h>
     37 #include <sys/reboot.h>
     38 
     39 #include <dev/acpi/acpica.h>
     40 #include <dev/acpi/acpireg.h>
     41 #include <dev/acpi/acpivar.h>
     42 
     43 #include <dev/pci/pcireg.h>
     44 #include <dev/pci/pcivar.h>
     45 
     46 #define NUM_ISA_INTERRUPTS	16
     47 #define NUM_ACPI_INTERRUPTS	256
     48 
     49 #define PCI_INVALID_IRQ	255
     50 #define PCI_INTERRUPT_VALID(x) ((x) != PCI_INVALID_IRQ && (x) != 0)
     51 
     52 #define ACPI_SERIAL_BEGIN(x)
     53 #define ACPI_SERIAL_END(x)
     54 
     55 /*
     56  * An ACPI PCI link device may contain multiple links.  Each link has its
     57  * own ACPI resource.  _PRT entries specify which link is being used via
     58  * the Source Index.
     59  *
     60  * XXX: A note about Source Indices and DPFs:  Currently we assume that
     61  * the DPF start and end tags are not counted towards the index that
     62  * Source Index corresponds to.  Also, we assume that when DPFs are in use
     63  * they various sets overlap in terms of Indices.  Here's an example
     64  * resource list indicating these assumptions:
     65  *
     66  * Resource		Index
     67  * --------		-----
     68  * I/O Port		0
     69  * Start DPF		-
     70  * IRQ			1
     71  * MemIO		2
     72  * Start DPF		-
     73  * IRQ			1
     74  * MemIO		2
     75  * End DPF		-
     76  * DMA Channel		3
     77  *
     78  * The XXX is because I'm not sure if this is a valid assumption to make.
     79  */
     80 
     81 /* States during DPF processing. */
     82 #define	DPF_OUTSIDE	0
     83 #define	DPF_FIRST	1
     84 #define	DPF_IGNORE	2
     85 
     86 struct link;
     87 
     88 struct acpi_pci_link_softc {
     89 	int	pl_num_links;
     90 	int	pl_crs_bad;
     91 	struct link *pl_links;
     92 	char pl_name[32];
     93 	ACPI_HANDLE pl_handle;
     94 	void *pl_powerhook;
     95 	TAILQ_ENTRY(acpi_pci_link_softc) pl_list;
     96 };
     97 
     98 static TAILQ_HEAD(, acpi_pci_link_softc) acpi_pci_linkdevs =
     99     TAILQ_HEAD_INITIALIZER(acpi_pci_linkdevs);
    100 
    101 
    102 struct link {
    103 	struct acpi_pci_link_softc *l_sc;
    104 	uint8_t	l_bios_irq;
    105 	uint8_t	l_irq;
    106 	uint8_t l_trig;
    107 	uint8_t l_pol;
    108 	uint8_t	l_initial_irq;
    109 	int	l_res_index;
    110 	int	l_num_irqs;
    111 	int	*l_irqs;
    112 	int	l_references;
    113 	int	l_dev_count;
    114 	pcitag_t *l_devices;
    115 	int	l_routed:1;
    116 	int	l_isa_irq:1;
    117 	ACPI_RESOURCE l_prs_template;
    118 };
    119 
    120 struct link_count_request {
    121 	int	in_dpf;
    122 	int	count;
    123 };
    124 
    125 struct link_res_request {
    126 	struct acpi_pci_link_softc *sc;
    127 	int	in_dpf;
    128 	int	res_index;
    129 	int	link_index;
    130 };
    131 
    132 MALLOC_DEFINE(M_PCI_LINK, "pci_link", "ACPI PCI Link structures");
    133 
    134 static int pci_link_interrupt_weights[NUM_ACPI_INTERRUPTS];
    135 static int pci_link_bios_isa_irqs;
    136 
    137 static ACPI_STATUS acpi_count_irq_resources(ACPI_RESOURCE *, void *);
    138 static ACPI_STATUS link_add_crs(ACPI_RESOURCE *, void *);
    139 static ACPI_STATUS link_add_prs(ACPI_RESOURCE *, void *);
    140 static int link_valid_irq(struct link *, int);
    141 static void acpi_pci_link_dump(struct acpi_pci_link_softc *);
    142 static int acpi_pci_link_attach(struct acpi_pci_link_softc *);
    143 static uint8_t acpi_pci_link_search_irq(struct acpi_pci_link_softc *, int, int,
    144 					int);
    145 static void acpi_pci_link_resume(int, void *);
    146 static struct link *acpi_pci_link_lookup(struct acpi_pci_link_softc *, int);
    147 static ACPI_STATUS acpi_pci_link_srs(struct acpi_pci_link_softc *,
    148 				     ACPI_BUFFER *);
    149 static ACPI_STATUS acpi_AppendBufferResource(ACPI_BUFFER *, ACPI_RESOURCE *);
    150 
    151 static ACPI_STATUS
    152 acpi_count_irq_resources(ACPI_RESOURCE *res, void *context)
    153 {
    154 	struct link_count_request *req;
    155 
    156 	req = (struct link_count_request *)context;
    157 	switch (res->Type) {
    158 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
    159 		switch (req->in_dpf) {
    160 		case DPF_OUTSIDE:
    161 			/* We've started the first DPF. */
    162 			req->in_dpf = DPF_FIRST;
    163 			break;
    164 		case DPF_FIRST:
    165 			/* We've started the second DPF. */
    166 			req->in_dpf = DPF_IGNORE;
    167 			break;
    168 		}
    169 		break;
    170 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
    171 		/* We are finished with DPF parsing. */
    172 		KASSERT(req->in_dpf != DPF_OUTSIDE);
    173 		req->in_dpf = DPF_OUTSIDE;
    174 		break;
    175 	case ACPI_RESOURCE_TYPE_IRQ:
    176 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
    177 		/*
    178 		 * Don't count resources if we are in a DPF set that we are
    179 		 * ignoring.
    180 		 */
    181 		if (req->in_dpf != DPF_IGNORE)
    182 			req->count++;
    183 	}
    184 	return (AE_OK);
    185 }
    186 
    187 static ACPI_STATUS
    188 link_add_crs(ACPI_RESOURCE *res, void *context)
    189 {
    190 	struct link_res_request *req;
    191 	struct link *link;
    192 
    193 	req = (struct link_res_request *)context;
    194 	switch (res->Type) {
    195 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
    196 		switch (req->in_dpf) {
    197 		case DPF_OUTSIDE:
    198 			/* We've started the first DPF. */
    199 			req->in_dpf = DPF_FIRST;
    200 			break;
    201 		case DPF_FIRST:
    202 			/* We've started the second DPF. */
    203 			panic(
    204 		"%s: Multiple dependent functions within a current resource",
    205 			    __func__);
    206 			break;
    207 		}
    208 		break;
    209 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
    210 		/* We are finished with DPF parsing. */
    211 		KASSERT(req->in_dpf != DPF_OUTSIDE);
    212 		req->in_dpf = DPF_OUTSIDE;
    213 		break;
    214 	case ACPI_RESOURCE_TYPE_IRQ:
    215 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
    216 		KASSERT(req->link_index < req->sc->pl_num_links);
    217 		link = &req->sc->pl_links[req->link_index];
    218 		link->l_res_index = req->res_index;
    219 		req->link_index++;
    220 		req->res_index++;
    221 
    222 		/*
    223 		 * Only use the current value if there's one IRQ.  Some
    224 		 * systems return multiple IRQs (which is nonsense for _CRS)
    225 		 * when the link hasn't been programmed.
    226 		 */
    227 		if (res->Type == ACPI_RESOURCE_TYPE_IRQ) {
    228 			if (res->Data.Irq.InterruptCount == 1) {
    229 				link->l_irq = res->Data.Irq.Interrupts[0];
    230 				link->l_trig = res->Data.Irq.Triggering;
    231 				link->l_pol = res->Data.Irq.Polarity;
    232 		}
    233 		} else if (res->Data.ExtendedIrq.InterruptCount == 1) {
    234 			link->l_irq = res->Data.ExtendedIrq.Interrupts[0];
    235 			link->l_trig = res->Data.ExtendedIrq.Triggering;
    236 			link->l_pol = res->Data.ExtendedIrq.Polarity;
    237 		}
    238 
    239 		/*
    240 		 * An IRQ of zero means that the link isn't routed.
    241 		 */
    242 		if (link->l_irq == 0)
    243 			link->l_irq = PCI_INVALID_IRQ;
    244 		break;
    245 	default:
    246 		req->res_index++;
    247 	}
    248 	return (AE_OK);
    249 }
    250 
    251 /*
    252  * Populate the set of possible IRQs for each device.
    253  */
    254 static ACPI_STATUS
    255 link_add_prs(ACPI_RESOURCE *res, void *context)
    256 {
    257 	struct link_res_request *req;
    258 	struct link *link;
    259 	UINT8 *irqs = NULL;
    260 	UINT32 *ext_irqs = NULL;
    261 	int i, is_ext_irq = 1;
    262 
    263 	req = (struct link_res_request *)context;
    264 	switch (res->Type) {
    265 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
    266 		switch (req->in_dpf) {
    267 		case DPF_OUTSIDE:
    268 			/* We've started the first DPF. */
    269 			req->in_dpf = DPF_FIRST;
    270 			break;
    271 		case DPF_FIRST:
    272 			/* We've started the second DPF. */
    273 			req->in_dpf = DPF_IGNORE;
    274 			break;
    275 		}
    276 		break;
    277 	case ACPI_RESOURCE_TYPE_END_DEPENDENT:
    278 		/* We are finished with DPF parsing. */
    279 		KASSERT(req->in_dpf != DPF_OUTSIDE);
    280 		req->in_dpf = DPF_OUTSIDE;
    281 		break;
    282 	case ACPI_RESOURCE_TYPE_IRQ:
    283 		is_ext_irq = 0;
    284 		/* fall through */
    285 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
    286 		/*
    287 		 * Don't parse resources if we are in a DPF set that we are
    288 		 * ignoring.
    289 		 */
    290 		if (req->in_dpf == DPF_IGNORE)
    291 			break;
    292 
    293 		KASSERT(req->link_index < req->sc->pl_num_links);
    294 		link = &req->sc->pl_links[req->link_index];
    295 		if (link->l_res_index == -1) {
    296 			KASSERT(req->sc->pl_crs_bad);
    297 			link->l_res_index = req->res_index;
    298 		}
    299 		req->link_index++;
    300 		req->res_index++;
    301 
    302 		/*
    303 		 * Stash a copy of the resource for later use when
    304 		 * doing _SRS.
    305 		 *
    306 		 * Note that in theory res->Length may exceed the size
    307 		 * of ACPI_RESOURCE, due to variable length lists in
    308 		 * subtypes.  However, all uses of l_prs_template only
    309 		 * rely on lists lengths of zero or one, for which
    310 		 * sizeof(ACPI_RESOURCE) is sufficient space anyway.
    311 		 * We cannot read longer than Length bytes, in case we
    312 		 * read off the end of mapped memory.  So we read
    313 		 * whichever length is shortest, Length or
    314 		 * sizeof(ACPI_RESOURCE).
    315 		 */
    316 		KASSERT(res->Length >= ACPI_RS_SIZE_MIN);
    317 
    318 		memset(&link->l_prs_template, 0, sizeof(link->l_prs_template));
    319 		memcpy(&link->l_prs_template, res,
    320 		       MIN(res->Length, sizeof(link->l_prs_template)));
    321 
    322 		if (is_ext_irq) {
    323 			link->l_num_irqs =
    324 			    res->Data.ExtendedIrq.InterruptCount;
    325 			link->l_trig = res->Data.ExtendedIrq.Triggering;
    326 			link->l_pol = res->Data.ExtendedIrq.Polarity;
    327 			ext_irqs = res->Data.ExtendedIrq.Interrupts;
    328 		} else {
    329 			link->l_num_irqs = res->Data.Irq.InterruptCount;
    330 			link->l_trig = res->Data.Irq.Triggering;
    331 			link->l_pol = res->Data.Irq.Polarity;
    332 			irqs = res->Data.Irq.Interrupts;
    333 		}
    334 		if (link->l_num_irqs == 0)
    335 			break;
    336 
    337 		/*
    338 		 * Save a list of the valid IRQs.  Also, if all of the
    339 		 * valid IRQs are ISA IRQs, then mark this link as
    340 		 * routed via an ISA interrupt.
    341 		 */
    342 		link->l_isa_irq = TRUE;
    343 		link->l_irqs = malloc(sizeof(int) * link->l_num_irqs,
    344 		    M_PCI_LINK, M_WAITOK | M_ZERO);
    345 		for (i = 0; i < link->l_num_irqs; i++) {
    346 			if (is_ext_irq) {
    347 				link->l_irqs[i] = ext_irqs[i];
    348 				if (ext_irqs[i] >= NUM_ISA_INTERRUPTS)
    349 					link->l_isa_irq = FALSE;
    350 			} else {
    351 				link->l_irqs[i] = irqs[i];
    352 				if (irqs[i] >= NUM_ISA_INTERRUPTS)
    353 					link->l_isa_irq = FALSE;
    354 			}
    355 		}
    356 		break;
    357 	default:
    358 		if (req->in_dpf == DPF_IGNORE)
    359 			break;
    360 		if (req->sc->pl_crs_bad)
    361 			aprint_normal("%s: Warning: possible resource %d "
    362 			       "will be lost during _SRS\n", req->sc->pl_name,
    363 			       req->res_index);
    364 		req->res_index++;
    365 	}
    366 	return (AE_OK);
    367 }
    368 
    369 static int
    370 link_valid_irq(struct link *link, int irq)
    371 {
    372 	int i;
    373 
    374 	/* Invalid interrupts are never valid. */
    375 	if (!PCI_INTERRUPT_VALID(irq))
    376 		return (FALSE);
    377 
    378 	/* Any interrupt in the list of possible interrupts is valid. */
    379 	for (i = 0; i < link->l_num_irqs; i++)
    380 		if (link->l_irqs[i] == irq)
    381 			 return (TRUE);
    382 
    383 	/*
    384 	 * For links routed via an ISA interrupt, if the SCI is routed via
    385 	 * an ISA interrupt, the SCI is always treated as a valid IRQ.
    386 	 */
    387 	if (link->l_isa_irq && AcpiGbl_FADT.SciInterrupt == irq &&
    388 	    irq < NUM_ISA_INTERRUPTS)
    389 		return (TRUE);
    390 
    391 	/* If the interrupt wasn't found in the list it is not valid. */
    392 	return (FALSE);
    393 }
    394 
    395 void
    396 acpi_pci_link_state(void)
    397 {
    398 	struct acpi_pci_link_softc *sc;
    399 
    400 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
    401 		acpi_pci_link_dump(sc);
    402 	}
    403 }
    404 
    405 static void
    406 acpi_pci_link_dump(struct acpi_pci_link_softc *sc)
    407 {
    408 	struct link *link;
    409 	int i, j;
    410 
    411 	printf("Link Device %s:\n", sc->pl_name);
    412 	printf("Index  IRQ  Rtd  Ref  IRQs\n");
    413 	for (i = 0; i < sc->pl_num_links; i++) {
    414 		link = &sc->pl_links[i];
    415 		printf("%5d  %3d   %c   %3d ", i, link->l_irq,
    416 		    link->l_routed ? 'Y' : 'N',  link->l_references);
    417 		if (link->l_num_irqs == 0)
    418 			printf(" none");
    419 		else for (j = 0; j < link->l_num_irqs; j++)
    420 			printf(" %d", link->l_irqs[j]);
    421 		printf(" polarity %u trigger %u\n", link->l_pol, link->l_trig);
    422 	}
    423 	printf("\n");
    424 }
    425 
    426 static int
    427 acpi_pci_link_attach(struct acpi_pci_link_softc *sc)
    428 {
    429 	struct link_count_request creq;
    430 	struct link_res_request rreq;
    431 	ACPI_STATUS status;
    432 	int i;
    433 
    434 	ACPI_SERIAL_BEGIN(pci_link);
    435 
    436 	/*
    437 	 * Count the number of current resources so we know how big of
    438 	 * a link array to allocate.  On some systems, _CRS is broken,
    439 	 * so for those systems try to derive the count from _PRS instead.
    440 	 */
    441 	creq.in_dpf = DPF_OUTSIDE;
    442 	creq.count = 0;
    443 	status = AcpiWalkResources(sc->pl_handle, "_CRS",
    444 	    acpi_count_irq_resources, &creq);
    445 	sc->pl_crs_bad = ACPI_FAILURE(status);
    446 	if (sc->pl_crs_bad) {
    447 		creq.in_dpf = DPF_OUTSIDE;
    448 		creq.count = 0;
    449 		status = AcpiWalkResources(sc->pl_handle, "_PRS",
    450 		    acpi_count_irq_resources, &creq);
    451 		if (ACPI_FAILURE(status)) {
    452 			aprint_error("%s: Unable to parse _CRS or _PRS: %s\n",
    453 			    sc->pl_name, AcpiFormatException(status));
    454 			ACPI_SERIAL_END(pci_link);
    455 			return (ENXIO);
    456 		}
    457 	}
    458 	sc->pl_num_links = creq.count;
    459 	if (creq.count == 0) {
    460 		ACPI_SERIAL_END(pci_link);
    461 		return (0);
    462 	}
    463 	sc->pl_links = malloc(sizeof(struct link) * sc->pl_num_links,
    464 	    M_PCI_LINK, M_WAITOK | M_ZERO);
    465 
    466 	/* Initialize the child links. */
    467 	for (i = 0; i < sc->pl_num_links; i++) {
    468 		sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
    469 		sc->pl_links[i].l_bios_irq = PCI_INVALID_IRQ;
    470 		sc->pl_links[i].l_sc = sc;
    471 		sc->pl_links[i].l_isa_irq = FALSE;
    472 		sc->pl_links[i].l_res_index = -1;
    473 		sc->pl_links[i].l_dev_count = 0;
    474 		sc->pl_links[i].l_devices = NULL;
    475 	}
    476 
    477 	/* Try to read the current settings from _CRS if it is valid. */
    478 	if (!sc->pl_crs_bad) {
    479 		rreq.in_dpf = DPF_OUTSIDE;
    480 		rreq.link_index = 0;
    481 		rreq.res_index = 0;
    482 		rreq.sc = sc;
    483 		status = AcpiWalkResources(sc->pl_handle, "_CRS",
    484 		    link_add_crs, &rreq);
    485 		if (ACPI_FAILURE(status)) {
    486 			aprint_error("%s: Unable to parse _CRS: %s\n",
    487 			    sc->pl_name, AcpiFormatException(status));
    488 			goto fail;
    489 		}
    490 	}
    491 
    492 	/*
    493 	 * Try to read the possible settings from _PRS.  Note that if the
    494 	 * _CRS is toast, we depend on having a working _PRS.  However, if
    495 	 * _CRS works, then it is ok for _PRS to be missing.
    496 	 */
    497 	rreq.in_dpf = DPF_OUTSIDE;
    498 	rreq.link_index = 0;
    499 	rreq.res_index = 0;
    500 	rreq.sc = sc;
    501 	status = AcpiWalkResources(sc->pl_handle, "_PRS",
    502 	    link_add_prs, &rreq);
    503 	if (ACPI_FAILURE(status) &&
    504 	    (status != AE_NOT_FOUND || sc->pl_crs_bad)) {
    505 		aprint_error("%s: Unable to parse _PRS: %s\n",
    506 		    sc->pl_name, AcpiFormatException(status));
    507 		goto fail;
    508 	}
    509 	if (boothowto & AB_VERBOSE) {
    510 		aprint_normal("%s: Links after initial probe:\n", sc->pl_name);
    511 		acpi_pci_link_dump(sc);
    512 	}
    513 
    514 	/* Verify initial IRQs if we have _PRS. */
    515 	if (status != AE_NOT_FOUND)
    516 		for (i = 0; i < sc->pl_num_links; i++)
    517 			if (!link_valid_irq(&sc->pl_links[i],
    518 			    sc->pl_links[i].l_irq))
    519 				sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
    520 	if (boothowto & AB_VERBOSE) {
    521 		printf("%s: Links after initial validation:\n", sc->pl_name);
    522 		acpi_pci_link_dump(sc);
    523 	}
    524 
    525 	/* Save initial IRQs. */
    526 	for (i = 0; i < sc->pl_num_links; i++)
    527 		sc->pl_links[i].l_initial_irq = sc->pl_links[i].l_irq;
    528 
    529 	/*
    530 	 * Try to disable this link.  If successful, set the current IRQ to
    531 	 * zero and flags to indicate this link is not routed.  If we can't
    532 	 * run _DIS (i.e., the method doesn't exist), assume the initial
    533 	 * IRQ was routed by the BIOS.
    534 	 */
    535 #if 0	/* XXX causes spontaneaous resets on some systems. Disabled for now. */
    536 	if (ACPI_SUCCESS(AcpiEvaluateObject(sc->pl_handle, "_DIS", NULL,
    537 	    NULL)))
    538 		for (i = 0; i < sc->pl_num_links; i++)
    539 			sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
    540 	else
    541 #endif
    542 		for (i = 0; i < sc->pl_num_links; i++)
    543 			if (PCI_INTERRUPT_VALID(sc->pl_links[i].l_irq))
    544 				sc->pl_links[i].l_routed = TRUE;
    545 	if (boothowto & AB_VERBOSE) {
    546 		printf("%s: Links after disable:\n", sc->pl_name);
    547 		acpi_pci_link_dump(sc);
    548 	}
    549 	ACPI_SERIAL_END(pci_link);
    550 	return (0);
    551 fail:
    552 	ACPI_SERIAL_END(pci_link);
    553 	for (i = 0; i < sc->pl_num_links; i++) {
    554 		if (sc->pl_links[i].l_irqs != NULL)
    555 			free(sc->pl_links[i].l_irqs, M_PCI_LINK);
    556 		if (sc->pl_links[i].l_devices != NULL)
    557 			free(sc->pl_links[i].l_devices, M_PCI_LINK);
    558 	}
    559 	free(sc->pl_links, M_PCI_LINK);
    560 	return (ENXIO);
    561 }
    562 
    563 static void
    564 acpi_pci_link_add_functions(struct acpi_pci_link_softc *sc, struct link *link,
    565     int bus, int device, int pin)
    566 {
    567 	uint32_t value;
    568 	uint8_t func, maxfunc, ipin;
    569 	pcitag_t tag;
    570 
    571 	tag = pci_make_tag(acpi_softc->sc_pc, bus, device, 0);
    572 	/* See if we have a valid device at function 0. */
    573 	value = pci_conf_read(acpi_softc->sc_pc, tag,  PCI_BHLC_REG);
    574 	if (PCI_HDRTYPE_TYPE(value) > PCI_HDRTYPE_PCB)
    575 		return;
    576 	if (PCI_HDRTYPE_MULTIFN(value))
    577 		maxfunc = 7;
    578 	else
    579 		maxfunc = 0;
    580 
    581 	/* Scan all possible functions at this device. */
    582 	for (func = 0; func <= maxfunc; func++) {
    583 		tag = pci_make_tag(acpi_softc->sc_pc, bus, device, func);
    584 		value = pci_conf_read(acpi_softc->sc_pc, tag, PCI_ID_REG);
    585 		if (PCI_VENDOR(value) == 0xffff)
    586 			continue;
    587 		value = pci_conf_read(acpi_softc->sc_pc, tag,
    588 		    PCI_INTERRUPT_REG);
    589 		ipin = PCI_INTERRUPT_PIN(value);
    590 		/*
    591 		 * See if it uses the pin in question.  Note that the passed
    592 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
    593 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
    594 		 */
    595 		if (ipin != pin + 1)
    596 			continue;
    597 
    598 		link->l_devices = realloc(link->l_devices,
    599 		    sizeof(pcitag_t) * (link->l_dev_count + 1),
    600 		    M_PCI_LINK, M_WAITOK);
    601 		link->l_devices[link->l_dev_count] = tag;
    602 		++link->l_dev_count;
    603 	}
    604 }
    605 
    606 static uint8_t
    607 acpi_pci_link_search_irq(struct acpi_pci_link_softc *sc, int bus, int device,
    608 			 int pin)
    609 {
    610 	uint32_t value;
    611 	uint8_t func, maxfunc, ipin, iline;
    612 	pcitag_t tag;
    613 
    614 	tag = pci_make_tag(acpi_softc->sc_pc, bus, device, 0);
    615 	/* See if we have a valid device at function 0. */
    616 	value = pci_conf_read(acpi_softc->sc_pc, tag,  PCI_BHLC_REG);
    617 	if (PCI_HDRTYPE_TYPE(value) > PCI_HDRTYPE_PCB)
    618 		return (PCI_INVALID_IRQ);
    619 	if (PCI_HDRTYPE_MULTIFN(value))
    620 		maxfunc = 7;
    621 	else
    622 		maxfunc = 0;
    623 
    624 	/* Scan all possible functions at this device. */
    625 	for (func = 0; func <= maxfunc; func++) {
    626 		tag = pci_make_tag(acpi_softc->sc_pc, bus, device, func);
    627 		value = pci_conf_read(acpi_softc->sc_pc, tag, PCI_ID_REG);
    628 		if (PCI_VENDOR(value) == 0xffff)
    629 			continue;
    630 		value = pci_conf_read(acpi_softc->sc_pc, tag,
    631 		    PCI_INTERRUPT_REG);
    632 		ipin = PCI_INTERRUPT_PIN(value);
    633 		iline = PCI_INTERRUPT_LINE(value);
    634 
    635 		/*
    636 		 * See if it uses the pin in question.  Note that the passed
    637 		 * in pin uses 0 for A, .. 3 for D whereas the intpin
    638 		 * register uses 0 for no interrupt, 1 for A, .. 4 for D.
    639 		 */
    640 		if (ipin != pin + 1)
    641 			continue;
    642 		aprint_verbose(
    643 		    "%s: ACPI: Found matching pin for %d.%d.INT%c"
    644 	            " at func %d: %d\n",
    645 			    sc->pl_name, bus, device, pin + 'A', func, iline);
    646 		if (PCI_INTERRUPT_VALID(iline))
    647 			return (iline);
    648 	}
    649 	return (PCI_INVALID_IRQ);
    650 }
    651 
    652 /*
    653  * Find the link structure that corresponds to the resource index passed in
    654  * via 'source_index'.
    655  */
    656 static struct link *
    657 acpi_pci_link_lookup(struct acpi_pci_link_softc *sc, int source_index)
    658 {
    659 	int i;
    660 
    661 	for (i = 0; i < sc->pl_num_links; i++)
    662 		if (sc->pl_links[i].l_res_index == source_index)
    663 			return (&sc->pl_links[i]);
    664 	return (NULL);
    665 }
    666 
    667 void
    668 acpi_pci_link_add_reference(void *v, int index, int bus, int slot, int pin)
    669 {
    670 	struct acpi_pci_link_softc *sc = v;
    671 	struct link *link;
    672 	uint8_t bios_irq;
    673 
    674 	/* Bump the reference count. */
    675 	ACPI_SERIAL_BEGIN(pci_link);
    676 	link = acpi_pci_link_lookup(sc, index);
    677 	if (link == NULL) {
    678 		printf("%s: apparently invalid index %d\n", sc->pl_name, index);
    679 		ACPI_SERIAL_END(pci_link);
    680 		return;
    681 	}
    682 	link->l_references++;
    683 	acpi_pci_link_add_functions(sc, link, bus, slot, pin);
    684 	if (link->l_routed)
    685 		pci_link_interrupt_weights[link->l_irq]++;
    686 
    687 	/*
    688 	 * The BIOS only routes interrupts via ISA IRQs using the ATPICs
    689 	 * (8259As).  Thus, if this link is routed via an ISA IRQ, go
    690 	 * look to see if the BIOS routed an IRQ for this link at the
    691 	 * indicated (bus, slot, pin).  If so, we prefer that IRQ for
    692 	 * this link and add that IRQ to our list of known-good IRQs.
    693 	 * This provides a good work-around for link devices whose _CRS
    694 	 * method is either broken or bogus.  We only use the value
    695 	 * returned by _CRS if we can't find a valid IRQ via this method
    696 	 * in fact.
    697 	 *
    698 	 * If this link is not routed via an ISA IRQ (because we are using
    699 	 * APIC for example), then don't bother looking up the BIOS IRQ
    700 	 * as if we find one it won't be valid anyway.
    701 	 */
    702 	if (!link->l_isa_irq) {
    703 		ACPI_SERIAL_END(pci_link);
    704 		return;
    705 	}
    706 
    707 	/* Try to find a BIOS IRQ setting from any matching devices. */
    708 	bios_irq = acpi_pci_link_search_irq(sc, bus, slot, pin);
    709 	if (!PCI_INTERRUPT_VALID(bios_irq)) {
    710 		ACPI_SERIAL_END(pci_link);
    711 		return;
    712 	}
    713 
    714 	/* Validate the BIOS IRQ. */
    715 	if (!link_valid_irq(link, bios_irq)) {
    716 		printf("%s: BIOS IRQ %u for %d.%d.INT%c is invalid\n",
    717 		    sc->pl_name, bios_irq, (int)bus, slot, pin + 'A');
    718 	} else if (!PCI_INTERRUPT_VALID(link->l_bios_irq)) {
    719 		link->l_bios_irq = bios_irq;
    720 		if (bios_irq < NUM_ISA_INTERRUPTS)
    721 			pci_link_bios_isa_irqs |= (1 << bios_irq);
    722 		if (bios_irq != link->l_initial_irq &&
    723 		    PCI_INTERRUPT_VALID(link->l_initial_irq))
    724 			printf(
    725 			    "%s: BIOS IRQ %u does not match initial IRQ %u\n",
    726 			    sc->pl_name, bios_irq, link->l_initial_irq);
    727 	} else if (bios_irq != link->l_bios_irq)
    728 		printf(
    729 	    "%s: BIOS IRQ %u for %d.%d.INT%c does not match "
    730 	    "previous BIOS IRQ %u\n",
    731 		    sc->pl_name, bios_irq, (int)bus, slot, pin + 'A',
    732 		    link->l_bios_irq);
    733 	ACPI_SERIAL_END(pci_link);
    734 }
    735 
    736 static ACPI_STATUS
    737 acpi_pci_link_srs_from_crs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
    738 {
    739 	ACPI_RESOURCE *resource, *end, newres, *resptr;
    740 	ACPI_BUFFER crsbuf;
    741 	ACPI_STATUS status;
    742 	struct link *link;
    743 	int i, in_dpf;
    744 
    745 	/* Fetch the _CRS. */
    746 	crsbuf.Pointer = NULL;
    747 	crsbuf.Length = ACPI_ALLOCATE_BUFFER;
    748 	status = AcpiGetCurrentResources(sc->pl_handle, &crsbuf);
    749 	if (ACPI_SUCCESS(status) && crsbuf.Pointer == NULL)
    750 		status = AE_NO_MEMORY;
    751 	if (ACPI_FAILURE(status)) {
    752 		aprint_verbose("%s: Unable to fetch current resources: %s\n",
    753 		    sc->pl_name, AcpiFormatException(status));
    754 		return (status);
    755 	}
    756 
    757 	/* Fill in IRQ resources via link structures. */
    758 	srsbuf->Pointer = NULL;
    759 	link = sc->pl_links;
    760 	i = 0;
    761 	in_dpf = DPF_OUTSIDE;
    762 	resource = (ACPI_RESOURCE *)crsbuf.Pointer;
    763 	end = (ACPI_RESOURCE *)((char *)crsbuf.Pointer + crsbuf.Length);
    764 	for (;;) {
    765 		switch (resource->Type) {
    766 		case ACPI_RESOURCE_TYPE_START_DEPENDENT:
    767 			switch (in_dpf) {
    768 			case DPF_OUTSIDE:
    769 				/* We've started the first DPF. */
    770 				in_dpf = DPF_FIRST;
    771 				break;
    772 			case DPF_FIRST:
    773 				/* We've started the second DPF. */
    774 				panic(
    775 		"%s: Multiple dependent functions within a current resource",
    776 				    __func__);
    777 				break;
    778 			}
    779 			resptr = NULL;
    780 			break;
    781 		case ACPI_RESOURCE_TYPE_END_DEPENDENT:
    782 			/* We are finished with DPF parsing. */
    783 			KASSERT(in_dpf != DPF_OUTSIDE);
    784 			in_dpf = DPF_OUTSIDE;
    785 			resptr = NULL;
    786 			break;
    787 		case ACPI_RESOURCE_TYPE_IRQ:
    788 			newres = link->l_prs_template;
    789 			resptr = &newres;
    790 			resptr->Data.Irq.InterruptCount = 1;
    791 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
    792 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS);
    793 				resptr->Data.Irq.Interrupts[0] = link->l_irq;
    794 				resptr->Data.Irq.Triggering = link->l_trig;
    795 				resptr->Data.Irq.Polarity = link->l_pol;
    796 			} else
    797 				resptr->Data.Irq.Interrupts[0] = 0;
    798 			link++;
    799 			i++;
    800 			break;
    801 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
    802 			newres = link->l_prs_template;
    803 			resptr = &newres;
    804 			resptr->Data.ExtendedIrq.InterruptCount = 1;
    805 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
    806 				resptr->Data.ExtendedIrq.Interrupts[0] =
    807 				    link->l_irq;
    808 				resptr->Data.ExtendedIrq.Triggering =
    809 				    link->l_trig;
    810 				resptr->Data.ExtendedIrq.Polarity = link->l_pol;
    811 			} else
    812 				resptr->Data.ExtendedIrq.Interrupts[0] = 0;
    813 			link++;
    814 			i++;
    815 			break;
    816 		default:
    817 			resptr = resource;
    818 		}
    819 		if (resptr != NULL) {
    820 			status = acpi_AppendBufferResource(srsbuf, resptr);
    821 			if (ACPI_FAILURE(status)) {
    822 				printf("%s: Unable to build resources: %s\n",
    823 				    sc->pl_name, AcpiFormatException(status));
    824 				if (srsbuf->Pointer != NULL)
    825 					AcpiOsFree(srsbuf->Pointer);
    826 				AcpiOsFree(crsbuf.Pointer);
    827 				return (status);
    828 			}
    829 		}
    830 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
    831 			break;
    832 		resource = ACPI_NEXT_RESOURCE(resource);
    833 		if (resource >= end)
    834 			break;
    835 	}
    836 	AcpiOsFree(crsbuf.Pointer);
    837 	return (AE_OK);
    838 }
    839 
    840 static ACPI_STATUS
    841 acpi_pci_link_srs_from_links(struct acpi_pci_link_softc *sc,
    842     ACPI_BUFFER *srsbuf)
    843 {
    844 	ACPI_RESOURCE newres;
    845 	ACPI_STATUS status;
    846 	struct link *link;
    847 	int i;
    848 
    849 	/* Start off with an empty buffer. */
    850 	srsbuf->Pointer = NULL;
    851 	link = sc->pl_links;
    852 	for (i = 0; i < sc->pl_num_links; i++) {
    853 
    854 		/* Add a new IRQ resource from each link. */
    855 		link = &sc->pl_links[i];
    856 		newres = link->l_prs_template;
    857 		if (newres.Type == ACPI_RESOURCE_TYPE_IRQ) {
    858 
    859 			/* Build an IRQ resource. */
    860 			newres.Data.Irq.InterruptCount = 1;
    861 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
    862 				KASSERT(link->l_irq < NUM_ISA_INTERRUPTS);
    863 				newres.Data.Irq.Interrupts[0] = link->l_irq;
    864 				newres.Data.Irq.Triggering = link->l_trig;
    865 				newres.Data.Irq.Polarity = link->l_pol;
    866 			} else
    867 				newres.Data.Irq.Interrupts[0] = 0;
    868 		} else {
    869 
    870 			/* Build an ExtIRQ resuorce. */
    871 			newres.Data.ExtendedIrq.InterruptCount = 1;
    872 			if (PCI_INTERRUPT_VALID(link->l_irq)) {
    873 				newres.Data.ExtendedIrq.Interrupts[0] =
    874 				    link->l_irq;
    875 				newres.Data.ExtendedIrq.Triggering =
    876 				    link->l_trig;
    877 				newres.Data.ExtendedIrq.Polarity =
    878 				    link->l_pol;
    879 			} else {
    880 				newres.Data.ExtendedIrq.Interrupts[0] = 0;
    881 			}
    882 		}
    883 
    884 		/* Add the new resource to the end of the _SRS buffer. */
    885 		status = acpi_AppendBufferResource(srsbuf, &newres);
    886 		if (ACPI_FAILURE(status)) {
    887 			printf("%s: Unable to build resources: %s\n",
    888 			    sc->pl_name, AcpiFormatException(status));
    889 			if (srsbuf->Pointer != NULL)
    890 				AcpiOsFree(srsbuf->Pointer);
    891 			return (status);
    892 		}
    893 	}
    894 	return (AE_OK);
    895 }
    896 
    897 static ACPI_STATUS
    898 acpi_pci_link_srs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
    899 {
    900 	ACPI_STATUS status;
    901 
    902 	if (sc->pl_crs_bad)
    903 		status = acpi_pci_link_srs_from_links(sc, srsbuf);
    904 	else
    905 		status = acpi_pci_link_srs_from_crs(sc, srsbuf);
    906 
    907 	/* Write out new resources via _SRS. */
    908 	return AcpiSetCurrentResources(sc->pl_handle, srsbuf);
    909 }
    910 
    911 static ACPI_STATUS
    912 acpi_pci_link_route_irqs(struct acpi_pci_link_softc *sc, int *irq, int *pol,
    913 			 int *trig)
    914 {
    915 	ACPI_RESOURCE *resource, *end;
    916 	ACPI_BUFFER srsbuf;
    917 	ACPI_STATUS status;
    918 	struct link *link;
    919 	int i, is_ext = 0;
    920 
    921 	status = acpi_pci_link_srs(sc, &srsbuf);
    922 	if (ACPI_FAILURE(status)) {
    923 		printf("%s: _SRS failed: %s\n",
    924 		    sc->pl_name, AcpiFormatException(status));
    925 		return (status);
    926 	}
    927 	/*
    928 	 * Perform acpi_config_intr() on each IRQ resource if it was just
    929 	 * routed for the first time.
    930 	 */
    931 	link = sc->pl_links;
    932 	i = 0;
    933 	resource = (ACPI_RESOURCE *)srsbuf.Pointer;
    934 	end = (ACPI_RESOURCE *)((char *)srsbuf.Pointer + srsbuf.Length);
    935 	for (;;) {
    936 		if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
    937 			break;
    938 		switch (resource->Type) {
    939 		case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
    940 			is_ext = 1;
    941 			/* FALLTHROUGH */
    942 		case ACPI_RESOURCE_TYPE_IRQ:
    943 			/*
    944 			 * Only configure the interrupt and update the
    945 			 * weights if this link has a valid IRQ and was
    946 			 * previously unrouted.
    947 			 */
    948 			if (!link->l_routed &&
    949 			    PCI_INTERRUPT_VALID(link->l_irq)) {
    950 				*trig = is_ext ?
    951 				    resource->Data.ExtendedIrq.Triggering :
    952 				    resource->Data.Irq.Triggering;
    953 				*pol = is_ext ?
    954 				    resource->Data.ExtendedIrq.Polarity :
    955 				    resource->Data.Irq.Polarity;
    956 				*irq = is_ext ?
    957 				    resource->Data.ExtendedIrq.Interrupts[0] :
    958 				    resource->Data.Irq.Interrupts[0];
    959 				link->l_routed = TRUE;
    960 				pci_link_interrupt_weights[link->l_irq] +=
    961 				    link->l_references;
    962 			}
    963 			link++;
    964 			i++;
    965 			break;
    966 		}
    967 		resource = ACPI_NEXT_RESOURCE(resource);
    968 		if (resource >= end)
    969 			break;
    970 	}
    971 	AcpiOsFree(srsbuf.Pointer);
    972 	return (AE_OK);
    973 }
    974 
    975 static void
    976 acpi_pci_link_resume(int why, void *arg)
    977 {
    978 	struct acpi_pci_link_softc *sc = arg;
    979 	ACPI_BUFFER srsbuf;
    980 
    981 	switch (why) {
    982 	case PWR_RESUME:
    983 		ACPI_SERIAL_BEGIN(pci_link);
    984 		if (ACPI_SUCCESS(acpi_pci_link_srs(sc, &srsbuf)))
    985 			AcpiOsFree(srsbuf.Pointer);
    986 		ACPI_SERIAL_END(pci_link);
    987 	default:
    988 		break;
    989 	}
    990 }
    991 
    992 /*
    993  * Pick an IRQ to use for this unrouted link.
    994  */
    995 static uint8_t
    996 acpi_pci_link_choose_irq(struct acpi_pci_link_softc *sc, struct link *link)
    997 {
    998 	u_int8_t best_irq, pos_irq;
    999 	int best_weight, pos_weight, i;
   1000 
   1001 	KASSERT(!link->l_routed);
   1002 	KASSERT(!PCI_INTERRUPT_VALID(link->l_irq));
   1003 
   1004 	/*
   1005 	 * If we have a valid BIOS IRQ, use that.  We trust what the BIOS
   1006 	 * says it routed over what _CRS says the link thinks is routed.
   1007 	 */
   1008 	if (PCI_INTERRUPT_VALID(link->l_bios_irq))
   1009 		return (link->l_bios_irq);
   1010 
   1011 	/*
   1012 	 * If we don't have a BIOS IRQ but do have a valid IRQ from _CRS,
   1013 	 * then use that.
   1014 	 */
   1015 	if (PCI_INTERRUPT_VALID(link->l_initial_irq))
   1016 		return (link->l_initial_irq);
   1017 
   1018 	/*
   1019 	 * Ok, we have no useful hints, so we have to pick from the
   1020 	 * possible IRQs.  For ISA IRQs we only use interrupts that
   1021 	 * have already been used by the BIOS.
   1022 	 */
   1023 	best_irq = PCI_INVALID_IRQ;
   1024 	best_weight = INT_MAX;
   1025 	for (i = 0; i < link->l_num_irqs; i++) {
   1026 		pos_irq = link->l_irqs[i];
   1027 		if (pos_irq < NUM_ISA_INTERRUPTS &&
   1028 		    (pci_link_bios_isa_irqs & 1 << pos_irq) == 0)
   1029 			continue;
   1030 		pos_weight = pci_link_interrupt_weights[pos_irq];
   1031 		if (pos_weight < best_weight) {
   1032 			best_weight = pos_weight;
   1033 			best_irq = pos_irq;
   1034 		}
   1035 	}
   1036 
   1037 	/*
   1038 	 * If this is an ISA IRQ, try using the SCI if it is also an ISA
   1039 	 * interrupt as a fallback.
   1040 	 */
   1041 	if (link->l_isa_irq && !PCI_INTERRUPT_VALID(best_irq)) {
   1042 		pos_irq = AcpiGbl_FADT.SciInterrupt;
   1043 		pos_weight = pci_link_interrupt_weights[pos_irq];
   1044 		if (pos_weight < best_weight) {
   1045 			best_weight = pos_weight;
   1046 			best_irq = pos_irq;
   1047 		}
   1048 	}
   1049 
   1050 	if (PCI_INTERRUPT_VALID(best_irq)) {
   1051 		aprint_verbose("%s: Picked IRQ %u with weight %d\n",
   1052 		    sc->pl_name, best_irq, best_weight);
   1053 	} else
   1054 		printf("%s: Unable to choose an IRQ\n", sc->pl_name);
   1055 	return (best_irq);
   1056 }
   1057 
   1058 int
   1059 acpi_pci_link_route_interrupt(void *v, int index, int *irq, int *pol, int *trig)
   1060 {
   1061 	struct acpi_pci_link_softc *sc = v;
   1062 	struct link *link;
   1063 	int i;
   1064 	pcireg_t reg;
   1065 
   1066 	ACPI_SERIAL_BEGIN(pci_link);
   1067 	link = acpi_pci_link_lookup(sc, index);
   1068 	if (link == NULL)
   1069 		panic("%s: apparently invalid index %d", __func__, index);
   1070 
   1071 	/*
   1072 	 * If this link device is already routed to an interrupt, just return
   1073 	 * the interrupt it is routed to.
   1074 	 */
   1075 	if (link->l_routed) {
   1076 		KASSERT(PCI_INTERRUPT_VALID(link->l_irq));
   1077 		ACPI_SERIAL_END(pci_link);
   1078 		*irq = link->l_irq;
   1079 		*pol = link->l_pol;
   1080 		*trig = link->l_trig;
   1081 		return (link->l_irq);
   1082 	}
   1083 
   1084 	/* Choose an IRQ if we need one. */
   1085 	if (PCI_INTERRUPT_VALID(link->l_irq)) {
   1086 		*irq = link->l_irq;
   1087 		*pol = link->l_pol;
   1088 		*trig = link->l_trig;
   1089 		goto done;
   1090 	}
   1091 
   1092 	link->l_irq = acpi_pci_link_choose_irq(sc, link);
   1093 
   1094 	/*
   1095 	 * Try to route the interrupt we picked.  If it fails, then
   1096 	 * assume the interrupt is not routed.
   1097 	 */
   1098 	if (!PCI_INTERRUPT_VALID(link->l_irq))
   1099 		goto done;
   1100 
   1101 	acpi_pci_link_route_irqs(sc, irq, pol, trig);
   1102 	if (!link->l_routed) {
   1103 		link->l_irq = PCI_INVALID_IRQ;
   1104 		goto done;
   1105 	}
   1106 
   1107 	link->l_pol = *pol;
   1108 	link->l_trig = *trig;
   1109 	for (i = 0; i < link->l_dev_count; ++i) {
   1110 		reg = pci_conf_read(acpi_softc->sc_pc, link->l_devices[i],
   1111 		    PCI_INTERRUPT_REG);
   1112 		reg &= ~(PCI_INTERRUPT_LINE_MASK << PCI_INTERRUPT_LINE_SHIFT);
   1113 		reg |= link->l_irq << PCI_INTERRUPT_LINE_SHIFT;
   1114 		pci_conf_write(acpi_softc->sc_pc, link->l_devices[i],
   1115 		    PCI_INTERRUPT_REG, reg);
   1116 	}
   1117 
   1118 done:
   1119 	ACPI_SERIAL_END(pci_link);
   1120 
   1121 	return (link->l_irq);
   1122 }
   1123 
   1124 /*
   1125  * This is gross, but we abuse the identify routine to perform one-time
   1126  * SYSINIT() style initialization for the driver.
   1127  */
   1128 static void
   1129 acpi_pci_link_init(struct acpi_pci_link_softc *sc)
   1130 {
   1131 	ACPI_BUFFER buf;
   1132 	char acpipcilinkname[] = "acpi_pci_link";
   1133 
   1134 	/*
   1135 	 * If the SCI is an ISA IRQ, add it to the bitmask of known good
   1136 	 * ISA IRQs.
   1137 	 *
   1138 	 * XXX: If we are using the APIC, the SCI might have been
   1139 	 * rerouted to an APIC pin in which case this is invalid.  However,
   1140 	 * if we are using the APIC, we also shouldn't be having any PCI
   1141 	 * interrupts routed via ISA IRQs, so this is probably ok.
   1142 	 */
   1143 	if (AcpiGbl_FADT.SciInterrupt < NUM_ISA_INTERRUPTS)
   1144 		pci_link_bios_isa_irqs |= (1 << AcpiGbl_FADT.SciInterrupt);
   1145 
   1146         sc->pl_powerhook = powerhook_establish(acpipcilinkname,
   1147 	    acpi_pci_link_resume, sc);
   1148         if (sc->pl_powerhook == NULL)
   1149                 aprint_normal("can't establish powerhook\n");
   1150 
   1151 	buf.Length = sizeof (sc->pl_name);
   1152 	buf.Pointer = sc->pl_name;
   1153 
   1154 	if (ACPI_FAILURE(AcpiGetName(sc->pl_handle, ACPI_SINGLE_NAME, &buf)))
   1155 		snprintf(sc->pl_name, sizeof (sc->pl_name), "%s",
   1156 		    "ACPI link device");
   1157 
   1158 	acpi_pci_link_attach(sc);
   1159 }
   1160 
   1161 void *
   1162 acpi_pci_link_devbyhandle(ACPI_HANDLE handle)
   1163 {
   1164 	struct acpi_pci_link_softc *sc;
   1165 
   1166 	TAILQ_FOREACH(sc, &acpi_pci_linkdevs, pl_list) {
   1167 		if (sc->pl_handle == handle)
   1168 			return sc;
   1169 	}
   1170 
   1171 	sc = malloc(sizeof (*sc), M_PCI_LINK, M_NOWAIT|M_ZERO);
   1172 	if (sc == NULL)
   1173 		return NULL;
   1174 
   1175 	sc->pl_handle = handle;
   1176 
   1177 	acpi_pci_link_init(sc);
   1178 
   1179 	TAILQ_INSERT_TAIL(&acpi_pci_linkdevs, sc, pl_list);
   1180 
   1181 	return (void *)sc;
   1182 }
   1183 
   1184 ACPI_HANDLE
   1185 acpi_pci_link_handle(void *v)
   1186 {
   1187 	struct acpi_pci_link_softc *sc = v;
   1188 
   1189 	return sc->pl_handle;
   1190 }
   1191 
   1192 char *
   1193 acpi_pci_link_name(void *v)
   1194 {
   1195 	struct acpi_pci_link_softc *sc = v;
   1196 
   1197 	return sc->pl_name;
   1198 }
   1199 
   1200 
   1201 /*
   1202  * Append an ACPI_RESOURCE to an ACPI_BUFFER.
   1203  *
   1204  * Given a pointer to an ACPI_RESOURCE structure, expand the ACPI_BUFFER
   1205  * provided to contain it.  If the ACPI_BUFFER is empty, allocate a sensible
   1206  * backing block.  If the ACPI_RESOURCE is NULL, return an empty set of
   1207  * resources.
   1208  */
   1209 #define ACPI_INITIAL_RESOURCE_BUFFER_SIZE	512
   1210 
   1211 static ACPI_STATUS
   1212 acpi_AppendBufferResource(ACPI_BUFFER *buf, ACPI_RESOURCE *res)
   1213 {
   1214 	ACPI_RESOURCE	*rp;
   1215 	void		*newp;
   1216 
   1217 	/* Initialise the buffer if necessary. */
   1218 	if (buf->Pointer == NULL) {
   1219 	buf->Length = ACPI_INITIAL_RESOURCE_BUFFER_SIZE;
   1220 	if ((buf->Pointer = AcpiOsAllocate(buf->Length)) == NULL)
   1221 		return (AE_NO_MEMORY);
   1222 	rp = (ACPI_RESOURCE *)buf->Pointer;
   1223 	rp->Type =  ACPI_RESOURCE_TYPE_END_TAG;
   1224 	rp->Length = 0;
   1225 	}
   1226 
   1227 	if (res == NULL)
   1228 		return (AE_OK);
   1229 
   1230 	/*
   1231 	 * Scan the current buffer looking for the terminator.
   1232 	 * This will either find the terminator or hit the end
   1233 	 * of the buffer and return an error.
   1234 	 */
   1235 	rp = (ACPI_RESOURCE *)buf->Pointer;
   1236 	for (;;) {
   1237 		/* Range check, don't go outside the buffer */
   1238 		if (rp >= (ACPI_RESOURCE *)((u_int8_t *)buf->Pointer +
   1239 		    buf->Length))
   1240 			return (AE_BAD_PARAMETER);
   1241 		if (rp->Type ==  ACPI_RESOURCE_TYPE_END_TAG || rp->Length == 0)
   1242 			break;
   1243 		rp = ACPI_NEXT_RESOURCE(rp);
   1244 	}
   1245 
   1246 	/*
   1247 	 * Check the size of the buffer and expand if required.
   1248 	 *
   1249 	 * Required size is:
   1250 	 *	size of existing resources before terminator +
   1251 	 *	size of new resource and header +
   1252 	 * 	size of terminator.
   1253 	 *
   1254 	 * Note that this loop should really only run once, unless
   1255 	 * for some reason we are stuffing a *really* huge resource.
   1256 	 */
   1257 	while ((((u_int8_t *)rp - (u_int8_t *)buf->Pointer) +
   1258 	    res->Length + ACPI_RS_SIZE_NO_DATA +
   1259 	    ACPI_RS_SIZE_MIN) >= buf->Length) {
   1260 		if ((newp = AcpiOsAllocate(buf->Length * 2)) == NULL)
   1261 			return (AE_NO_MEMORY);
   1262 		memcpy(newp, buf->Pointer, buf->Length);
   1263 		rp = (ACPI_RESOURCE *)((u_int8_t *)newp +
   1264 		   ((u_int8_t *)rp - (u_int8_t *)buf->Pointer));
   1265 		AcpiOsFree(buf->Pointer);
   1266 		buf->Pointer = newp;
   1267 		buf->Length += buf->Length;
   1268 	}
   1269 
   1270 	/* Insert the new resource. */
   1271 	memcpy(rp, res, res->Length + ACPI_RS_SIZE_NO_DATA);
   1272 
   1273 	/* And add the terminator. */
   1274 	rp = ACPI_NEXT_RESOURCE(rp);
   1275 	rp->Type =  ACPI_RESOURCE_TYPE_END_TAG;
   1276 	rp->Length = 0;
   1277 
   1278 	return (AE_OK);
   1279 }
   1280