The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/dev/acpica/acpi_pci_link.c

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    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: releng/10.4/sys/dev/acpica/acpi_pci_link.c 249767 2013-04-22 15:51:06Z jhb $");
   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/include/acpi.h>
   39 
   40 #include <dev/acpica/acpivar.h>
   41 #include <dev/acpica/acpi_pcibvar.h>
   42 
   43 #include <machine/pci_cfgreg.h>
   44 #include <dev/pci/pcireg.h>
   45 #include <dev/pci/pcivar.h>
   46 #include "pcib_if.h"
   47 
   48 /* Hooks for the ACPI CA debugging infrastructure. */
   49 #define _COMPONENT      ACPI_BUS
   50 ACPI_MODULE_NAME("PCI_LINK")
   51 
   52 ACPI_SERIAL_DECL(pci_link, "ACPI PCI link");
   53 
   54 #define NUM_ISA_INTERRUPTS      16
   55 #define NUM_ACPI_INTERRUPTS     256
   56 
   57 /*
   58  * An ACPI PCI link device may contain multiple links.  Each link has its
   59  * own ACPI resource.  _PRT entries specify which link is being used via
   60  * the Source Index.
   61  *
   62  * XXX: A note about Source Indices and DPFs:  Currently we assume that
   63  * the DPF start and end tags are not counted towards the index that
   64  * Source Index corresponds to.  Also, we assume that when DPFs are in use
   65  * they various sets overlap in terms of Indices.  Here's an example
   66  * resource list indicating these assumptions:
   67  *
   68  * Resource             Index
   69  * --------             -----
   70  * I/O Port             0
   71  * Start DPF            -
   72  * IRQ                  1
   73  * MemIO                2
   74  * Start DPF            -
   75  * IRQ                  1
   76  * MemIO                2
   77  * End DPF              -
   78  * DMA Channel          3
   79  *
   80  * The XXX is because I'm not sure if this is a valid assumption to make.
   81  */
   82 
   83 /* States during DPF processing. */
   84 #define DPF_OUTSIDE     0
   85 #define DPF_FIRST       1
   86 #define DPF_IGNORE      2
   87 
   88 struct link;
   89 
   90 struct acpi_pci_link_softc {
   91         int     pl_num_links;
   92         int     pl_crs_bad;
   93         struct link *pl_links;
   94         device_t pl_dev;
   95 };
   96 
   97 struct link {
   98         struct acpi_pci_link_softc *l_sc;
   99         uint8_t l_bios_irq;
  100         uint8_t l_irq;
  101         uint8_t l_initial_irq;
  102         UINT32  l_crs_type;
  103         int     l_res_index;
  104         int     l_num_irqs;
  105         int     *l_irqs;
  106         int     l_references;
  107         int     l_routed:1;
  108         int     l_isa_irq:1;
  109         ACPI_RESOURCE l_prs_template;
  110 };
  111 
  112 struct link_count_request {
  113         int     in_dpf;
  114         int     count;
  115 };
  116 
  117 struct link_res_request {
  118         struct acpi_pci_link_softc *sc;
  119         int     in_dpf;
  120         int     res_index;
  121         int     link_index;
  122 };
  123 
  124 static MALLOC_DEFINE(M_PCI_LINK, "pci_link", "ACPI PCI Link structures");
  125 
  126 static int pci_link_interrupt_weights[NUM_ACPI_INTERRUPTS];
  127 static int pci_link_bios_isa_irqs;
  128 
  129 static char *pci_link_ids[] = { "PNP0C0F", NULL };
  130 
  131 /*
  132  * Fetch the short name associated with an ACPI handle and save it in the
  133  * passed in buffer.
  134  */
  135 static ACPI_STATUS
  136 acpi_short_name(ACPI_HANDLE handle, char *buffer, size_t buflen)
  137 {
  138         ACPI_BUFFER buf;
  139 
  140         buf.Length = buflen;
  141         buf.Pointer = buffer;
  142         return (AcpiGetName(handle, ACPI_SINGLE_NAME, &buf));
  143 }
  144 
  145 static int
  146 acpi_pci_link_probe(device_t dev)
  147 {
  148         char descr[28], name[12];
  149 
  150         /*
  151          * We explicitly do not check _STA since not all systems set it to
  152          * sensible values.
  153          */
  154         if (acpi_disabled("pci_link") ||
  155             ACPI_ID_PROBE(device_get_parent(dev), dev, pci_link_ids) == NULL)
  156                 return (ENXIO);
  157 
  158         if (ACPI_SUCCESS(acpi_short_name(acpi_get_handle(dev), name,
  159             sizeof(name)))) {
  160                 snprintf(descr, sizeof(descr), "ACPI PCI Link %s", name);
  161                 device_set_desc_copy(dev, descr);
  162         } else
  163                 device_set_desc(dev, "ACPI PCI Link");
  164         device_quiet(dev);
  165         return (0);
  166 }
  167 
  168 static ACPI_STATUS
  169 acpi_count_irq_resources(ACPI_RESOURCE *res, void *context)
  170 {
  171         struct link_count_request *req;
  172 
  173         req = (struct link_count_request *)context;
  174         switch (res->Type) {
  175         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
  176                 switch (req->in_dpf) {
  177                 case DPF_OUTSIDE:
  178                         /* We've started the first DPF. */
  179                         req->in_dpf = DPF_FIRST;
  180                         break;
  181                 case DPF_FIRST:
  182                         /* We've started the second DPF. */
  183                         req->in_dpf = DPF_IGNORE;
  184                         break;
  185                 }
  186                 break;
  187         case ACPI_RESOURCE_TYPE_END_DEPENDENT:
  188                 /* We are finished with DPF parsing. */
  189                 KASSERT(req->in_dpf != DPF_OUTSIDE,
  190                     ("%s: end dpf when not parsing a dpf", __func__));
  191                 req->in_dpf = DPF_OUTSIDE;
  192                 break;
  193         case ACPI_RESOURCE_TYPE_IRQ:
  194         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
  195                 /*
  196                  * Don't count resources if we are in a DPF set that we are
  197                  * ignoring.
  198                  */
  199                 if (req->in_dpf != DPF_IGNORE)
  200                         req->count++;
  201         }
  202         return (AE_OK);
  203 }
  204 
  205 static ACPI_STATUS
  206 link_add_crs(ACPI_RESOURCE *res, void *context)
  207 {
  208         struct link_res_request *req;
  209         struct link *link;
  210 
  211         ACPI_SERIAL_ASSERT(pci_link);
  212         req = (struct link_res_request *)context;
  213         switch (res->Type) {
  214         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
  215                 switch (req->in_dpf) {
  216                 case DPF_OUTSIDE:
  217                         /* We've started the first DPF. */
  218                         req->in_dpf = DPF_FIRST;
  219                         break;
  220                 case DPF_FIRST:
  221                         /* We've started the second DPF. */
  222                         panic(
  223                 "%s: Multiple dependent functions within a current resource",
  224                             __func__);
  225                         break;
  226                 }
  227                 break;
  228         case ACPI_RESOURCE_TYPE_END_DEPENDENT:
  229                 /* We are finished with DPF parsing. */
  230                 KASSERT(req->in_dpf != DPF_OUTSIDE,
  231                     ("%s: end dpf when not parsing a dpf", __func__));
  232                 req->in_dpf = DPF_OUTSIDE;
  233                 break;
  234         case ACPI_RESOURCE_TYPE_IRQ:
  235         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
  236                 KASSERT(req->link_index < req->sc->pl_num_links,
  237                     ("%s: array boundary violation", __func__));
  238                 link = &req->sc->pl_links[req->link_index];
  239                 link->l_res_index = req->res_index;
  240                 link->l_crs_type = res->Type;
  241                 req->link_index++;
  242                 req->res_index++;
  243 
  244                 /*
  245                  * Only use the current value if there's one IRQ.  Some
  246                  * systems return multiple IRQs (which is nonsense for _CRS)
  247                  * when the link hasn't been programmed.
  248                  */
  249                 if (res->Type == ACPI_RESOURCE_TYPE_IRQ) {
  250                         if (res->Data.Irq.InterruptCount == 1)
  251                                 link->l_irq = res->Data.Irq.Interrupts[0];
  252                 } else if (res->Data.ExtendedIrq.InterruptCount == 1)
  253                         link->l_irq = res->Data.ExtendedIrq.Interrupts[0];
  254 
  255                 /*
  256                  * An IRQ of zero means that the link isn't routed.
  257                  */
  258                 if (link->l_irq == 0)
  259                         link->l_irq = PCI_INVALID_IRQ;
  260                 break;
  261         default:
  262                 req->res_index++;
  263         }
  264         return (AE_OK);
  265 }
  266 
  267 /*
  268  * Populate the set of possible IRQs for each device.
  269  */
  270 static ACPI_STATUS
  271 link_add_prs(ACPI_RESOURCE *res, void *context)
  272 {
  273         ACPI_RESOURCE *tmp;
  274         struct link_res_request *req;
  275         struct link *link;
  276         UINT8 *irqs = NULL;
  277         UINT32 *ext_irqs = NULL;
  278         int i, is_ext_irq = 1;
  279 
  280         ACPI_SERIAL_ASSERT(pci_link);
  281         req = (struct link_res_request *)context;
  282         switch (res->Type) {
  283         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
  284                 switch (req->in_dpf) {
  285                 case DPF_OUTSIDE:
  286                         /* We've started the first DPF. */
  287                         req->in_dpf = DPF_FIRST;
  288                         break;
  289                 case DPF_FIRST:
  290                         /* We've started the second DPF. */
  291                         req->in_dpf = DPF_IGNORE;
  292                         break;
  293                 }
  294                 break;
  295         case ACPI_RESOURCE_TYPE_END_DEPENDENT:
  296                 /* We are finished with DPF parsing. */
  297                 KASSERT(req->in_dpf != DPF_OUTSIDE,
  298                     ("%s: end dpf when not parsing a dpf", __func__));
  299                 req->in_dpf = DPF_OUTSIDE;
  300                 break;
  301         case ACPI_RESOURCE_TYPE_IRQ:
  302                 is_ext_irq = 0;
  303                 /* fall through */
  304         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
  305                 /*
  306                  * Don't parse resources if we are in a DPF set that we are
  307                  * ignoring.
  308                  */
  309                 if (req->in_dpf == DPF_IGNORE)
  310                         break;
  311 
  312                 KASSERT(req->link_index < req->sc->pl_num_links,
  313                     ("%s: array boundary violation", __func__));
  314                 link = &req->sc->pl_links[req->link_index];
  315                 if (link->l_res_index == -1) {
  316                         KASSERT(req->sc->pl_crs_bad,
  317                             ("res_index should be set"));
  318                         link->l_res_index = req->res_index;
  319                 }
  320                 req->link_index++;
  321                 req->res_index++;
  322 
  323                 /*
  324                  * Stash a copy of the resource for later use when doing
  325                  * _SRS.
  326                  */
  327                 tmp = &link->l_prs_template;
  328                 if (is_ext_irq) {
  329                         bcopy(res, tmp, ACPI_RS_SIZE(tmp->Data.ExtendedIrq));
  330 
  331                         /*
  332                          * XXX acpi_AppendBufferResource() cannot handle
  333                          * optional data.
  334                          */
  335                         bzero(&tmp->Data.ExtendedIrq.ResourceSource,
  336                             sizeof(tmp->Data.ExtendedIrq.ResourceSource));
  337                         tmp->Length = ACPI_RS_SIZE(tmp->Data.ExtendedIrq);
  338 
  339                         link->l_num_irqs =
  340                             res->Data.ExtendedIrq.InterruptCount;
  341                         ext_irqs = res->Data.ExtendedIrq.Interrupts;
  342                 } else {
  343                         bcopy(res, tmp, ACPI_RS_SIZE(tmp->Data.Irq));
  344                         link->l_num_irqs = res->Data.Irq.InterruptCount;
  345                         irqs = res->Data.Irq.Interrupts;
  346                 }
  347                 if (link->l_num_irqs == 0)
  348                         break;
  349 
  350                 /*
  351                  * Save a list of the valid IRQs.  Also, if all of the
  352                  * valid IRQs are ISA IRQs, then mark this link as
  353                  * routed via an ISA interrupt.
  354                  */
  355                 link->l_isa_irq = TRUE;
  356                 link->l_irqs = malloc(sizeof(int) * link->l_num_irqs,
  357                     M_PCI_LINK, M_WAITOK | M_ZERO);
  358                 for (i = 0; i < link->l_num_irqs; i++) {
  359                         if (is_ext_irq) {
  360                                 link->l_irqs[i] = ext_irqs[i];
  361                                 if (ext_irqs[i] >= NUM_ISA_INTERRUPTS)
  362                                         link->l_isa_irq = FALSE;
  363                         } else {
  364                                 link->l_irqs[i] = irqs[i];
  365                                 if (irqs[i] >= NUM_ISA_INTERRUPTS)
  366                                         link->l_isa_irq = FALSE;
  367                         }
  368                 }
  369 
  370                 /*
  371                  * If this is not an ISA IRQ but _CRS used a non-extended
  372                  * IRQ descriptor, don't use _CRS as a template for _SRS.
  373                  */
  374                 if (!req->sc->pl_crs_bad && !link->l_isa_irq &&
  375                     link->l_crs_type == ACPI_RESOURCE_TYPE_IRQ)
  376                         req->sc->pl_crs_bad = TRUE;
  377                 break;
  378         default:
  379                 if (req->in_dpf == DPF_IGNORE)
  380                         break;
  381                 if (req->sc->pl_crs_bad)
  382                         device_printf(req->sc->pl_dev,
  383                     "Warning: possible resource %d will be lost during _SRS\n",
  384                             req->res_index);
  385                 req->res_index++;
  386         }
  387         return (AE_OK);
  388 }
  389 
  390 static int
  391 link_valid_irq(struct link *link, int irq)
  392 {
  393         int i;
  394 
  395         ACPI_SERIAL_ASSERT(pci_link);
  396 
  397         /* Invalid interrupts are never valid. */
  398         if (!PCI_INTERRUPT_VALID(irq))
  399                 return (FALSE);
  400 
  401         /* Any interrupt in the list of possible interrupts is valid. */
  402         for (i = 0; i < link->l_num_irqs; i++)
  403                 if (link->l_irqs[i] == irq)
  404                          return (TRUE);
  405 
  406         /*
  407          * For links routed via an ISA interrupt, if the SCI is routed via
  408          * an ISA interrupt, the SCI is always treated as a valid IRQ.
  409          */
  410         if (link->l_isa_irq && AcpiGbl_FADT.SciInterrupt == irq &&
  411             irq < NUM_ISA_INTERRUPTS)
  412                 return (TRUE);
  413 
  414         /* If the interrupt wasn't found in the list it is not valid. */
  415         return (FALSE);
  416 }
  417 
  418 static void
  419 acpi_pci_link_dump(struct acpi_pci_link_softc *sc, int header, const char *tag)
  420 {
  421         struct link *link;
  422         char buf[16];
  423         int i, j;
  424 
  425         ACPI_SERIAL_ASSERT(pci_link);
  426         if (header) {
  427                 snprintf(buf, sizeof(buf), "%s:",
  428                     device_get_nameunit(sc->pl_dev));
  429                 printf("%-16.16s  Index  IRQ  Rtd  Ref  IRQs\n", buf);
  430         }
  431         for (i = 0; i < sc->pl_num_links; i++) {
  432                 link = &sc->pl_links[i];
  433                 printf("  %-14.14s  %5d  %3d   %c   %3d ", i == 0 ? tag : "", i,
  434                     link->l_irq, link->l_routed ? 'Y' : 'N',
  435                     link->l_references);
  436                 if (link->l_num_irqs == 0)
  437                         printf(" none");
  438                 else for (j = 0; j < link->l_num_irqs; j++)
  439                         printf(" %d", link->l_irqs[j]);
  440                 printf("\n");
  441         }
  442 }
  443 
  444 static int
  445 acpi_pci_link_attach(device_t dev)
  446 {
  447         struct acpi_pci_link_softc *sc;
  448         struct link_count_request creq;
  449         struct link_res_request rreq;
  450         ACPI_STATUS status;
  451         int i;
  452 
  453         sc = device_get_softc(dev);
  454         sc->pl_dev = dev;
  455         ACPI_SERIAL_BEGIN(pci_link);
  456 
  457         /*
  458          * Count the number of current resources so we know how big of
  459          * a link array to allocate.  On some systems, _CRS is broken,
  460          * so for those systems try to derive the count from _PRS instead.
  461          */
  462         creq.in_dpf = DPF_OUTSIDE;
  463         creq.count = 0;
  464         status = AcpiWalkResources(acpi_get_handle(dev), "_CRS",
  465             acpi_count_irq_resources, &creq);
  466         sc->pl_crs_bad = ACPI_FAILURE(status);
  467         if (sc->pl_crs_bad) {
  468                 creq.in_dpf = DPF_OUTSIDE;
  469                 creq.count = 0;
  470                 status = AcpiWalkResources(acpi_get_handle(dev), "_PRS",
  471                     acpi_count_irq_resources, &creq);
  472                 if (ACPI_FAILURE(status)) {
  473                         device_printf(dev,
  474                             "Unable to parse _CRS or _PRS: %s\n",
  475                             AcpiFormatException(status));
  476                         ACPI_SERIAL_END(pci_link);
  477                         return (ENXIO);
  478                 }
  479         }
  480         sc->pl_num_links = creq.count;
  481         if (creq.count == 0) {
  482                 ACPI_SERIAL_END(pci_link);
  483                 return (0);
  484         }
  485         sc->pl_links = malloc(sizeof(struct link) * sc->pl_num_links,
  486             M_PCI_LINK, M_WAITOK | M_ZERO);
  487 
  488         /* Initialize the child links. */
  489         for (i = 0; i < sc->pl_num_links; i++) {
  490                 sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
  491                 sc->pl_links[i].l_bios_irq = PCI_INVALID_IRQ;
  492                 sc->pl_links[i].l_sc = sc;
  493                 sc->pl_links[i].l_isa_irq = FALSE;
  494                 sc->pl_links[i].l_res_index = -1;
  495         }
  496 
  497         /* Try to read the current settings from _CRS if it is valid. */
  498         if (!sc->pl_crs_bad) {
  499                 rreq.in_dpf = DPF_OUTSIDE;
  500                 rreq.link_index = 0;
  501                 rreq.res_index = 0;
  502                 rreq.sc = sc;
  503                 status = AcpiWalkResources(acpi_get_handle(dev), "_CRS",
  504                     link_add_crs, &rreq);
  505                 if (ACPI_FAILURE(status)) {
  506                         device_printf(dev, "Unable to parse _CRS: %s\n",
  507                             AcpiFormatException(status));
  508                         goto fail;
  509                 }
  510         }
  511 
  512         /*
  513          * Try to read the possible settings from _PRS.  Note that if the
  514          * _CRS is toast, we depend on having a working _PRS.  However, if
  515          * _CRS works, then it is ok for _PRS to be missing.
  516          */
  517         rreq.in_dpf = DPF_OUTSIDE;
  518         rreq.link_index = 0;
  519         rreq.res_index = 0;
  520         rreq.sc = sc;
  521         status = AcpiWalkResources(acpi_get_handle(dev), "_PRS",
  522             link_add_prs, &rreq);
  523         if (ACPI_FAILURE(status) &&
  524             (status != AE_NOT_FOUND || sc->pl_crs_bad)) {
  525                 device_printf(dev, "Unable to parse _PRS: %s\n",
  526                     AcpiFormatException(status));
  527                 goto fail;
  528         }
  529         if (bootverbose)
  530                 acpi_pci_link_dump(sc, 1, "Initial Probe");
  531 
  532         /* Verify initial IRQs if we have _PRS. */
  533         if (status != AE_NOT_FOUND)
  534                 for (i = 0; i < sc->pl_num_links; i++)
  535                         if (!link_valid_irq(&sc->pl_links[i],
  536                             sc->pl_links[i].l_irq))
  537                                 sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
  538         if (bootverbose)
  539                 acpi_pci_link_dump(sc, 0, "Validation");
  540 
  541         /* Save initial IRQs. */
  542         for (i = 0; i < sc->pl_num_links; i++)
  543                 sc->pl_links[i].l_initial_irq = sc->pl_links[i].l_irq;
  544 
  545         /*
  546          * Try to disable this link.  If successful, set the current IRQ to
  547          * zero and flags to indicate this link is not routed.  If we can't
  548          * run _DIS (i.e., the method doesn't exist), assume the initial
  549          * IRQ was routed by the BIOS.
  550          */
  551         if (ACPI_SUCCESS(AcpiEvaluateObject(acpi_get_handle(dev), "_DIS", NULL,
  552             NULL)))
  553                 for (i = 0; i < sc->pl_num_links; i++)
  554                         sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
  555         else
  556                 for (i = 0; i < sc->pl_num_links; i++)
  557                         if (PCI_INTERRUPT_VALID(sc->pl_links[i].l_irq))
  558                                 sc->pl_links[i].l_routed = TRUE;
  559         if (bootverbose)
  560                 acpi_pci_link_dump(sc, 0, "After Disable");
  561         ACPI_SERIAL_END(pci_link);
  562         return (0);
  563 fail:
  564         ACPI_SERIAL_END(pci_link);
  565         for (i = 0; i < sc->pl_num_links; i++)
  566                 if (sc->pl_links[i].l_irqs != NULL)
  567                         free(sc->pl_links[i].l_irqs, M_PCI_LINK);
  568         free(sc->pl_links, M_PCI_LINK);
  569         return (ENXIO);
  570 }
  571 
  572 /* XXX: Note that this is identical to pci_pir_search_irq(). */
  573 static uint8_t
  574 acpi_pci_link_search_irq(int bus, int device, int pin)
  575 {
  576         uint32_t value;
  577         uint8_t func, maxfunc;
  578 
  579         /* See if we have a valid device at function 0. */
  580         value = pci_cfgregread(bus, device, 0, PCIR_HDRTYPE, 1);
  581         if ((value & PCIM_HDRTYPE) > PCI_MAXHDRTYPE)
  582                 return (PCI_INVALID_IRQ);
  583         if (value & PCIM_MFDEV)
  584                 maxfunc = PCI_FUNCMAX;
  585         else
  586                 maxfunc = 0;
  587 
  588         /* Scan all possible functions at this device. */
  589         for (func = 0; func <= maxfunc; func++) {
  590                 value = pci_cfgregread(bus, device, func, PCIR_DEVVENDOR, 4);
  591                 if (value == 0xffffffff)
  592                         continue;
  593                 value = pci_cfgregread(bus, device, func, PCIR_INTPIN, 1);
  594 
  595                 /*
  596                  * See if it uses the pin in question.  Note that the passed
  597                  * in pin uses 0 for A, .. 3 for D whereas the intpin
  598                  * register uses 0 for no interrupt, 1 for A, .. 4 for D.
  599                  */
  600                 if (value != pin + 1)
  601                         continue;
  602                 value = pci_cfgregread(bus, device, func, PCIR_INTLINE, 1);
  603                 if (bootverbose)
  604                         printf(
  605                 "ACPI: Found matching pin for %d.%d.INT%c at func %d: %d\n",
  606                             bus, device, pin + 'A', func, value);
  607                 if (value != PCI_INVALID_IRQ)
  608                         return (value);
  609         }
  610         return (PCI_INVALID_IRQ);
  611 }
  612 
  613 /*
  614  * Find the link structure that corresponds to the resource index passed in
  615  * via 'source_index'.
  616  */
  617 static struct link *
  618 acpi_pci_link_lookup(device_t dev, int source_index)
  619 {
  620         struct acpi_pci_link_softc *sc;
  621         int i;
  622 
  623         ACPI_SERIAL_ASSERT(pci_link);
  624         sc = device_get_softc(dev);
  625         for (i = 0; i < sc->pl_num_links; i++)
  626                 if (sc->pl_links[i].l_res_index == source_index)
  627                         return (&sc->pl_links[i]);
  628         return (NULL);
  629 }
  630 
  631 void
  632 acpi_pci_link_add_reference(device_t dev, int index, device_t pcib, int slot,
  633     int pin)
  634 {
  635         struct link *link;
  636         uint8_t bios_irq;
  637         uintptr_t bus;
  638 
  639         /*
  640          * Look up the PCI bus for the specified PCI bridge device.  Note
  641          * that the PCI bridge device might not have any children yet.
  642          * However, looking up its bus number doesn't require a valid child
  643          * device, so we just pass NULL.
  644          */
  645         if (BUS_READ_IVAR(pcib, NULL, PCIB_IVAR_BUS, &bus) != 0) {
  646                 device_printf(pcib, "Unable to read PCI bus number");
  647                 panic("PCI bridge without a bus number");
  648         }
  649                 
  650         /* Bump the reference count. */
  651         ACPI_SERIAL_BEGIN(pci_link);
  652         link = acpi_pci_link_lookup(dev, index);
  653         if (link == NULL) {
  654                 device_printf(dev, "apparently invalid index %d\n", index);
  655                 ACPI_SERIAL_END(pci_link);
  656                 return;
  657         }
  658         link->l_references++;
  659         if (link->l_routed)
  660                 pci_link_interrupt_weights[link->l_irq]++;
  661 
  662         /*
  663          * The BIOS only routes interrupts via ISA IRQs using the ATPICs
  664          * (8259As).  Thus, if this link is routed via an ISA IRQ, go
  665          * look to see if the BIOS routed an IRQ for this link at the
  666          * indicated (bus, slot, pin).  If so, we prefer that IRQ for
  667          * this link and add that IRQ to our list of known-good IRQs.
  668          * This provides a good work-around for link devices whose _CRS
  669          * method is either broken or bogus.  We only use the value
  670          * returned by _CRS if we can't find a valid IRQ via this method
  671          * in fact.
  672          *
  673          * If this link is not routed via an ISA IRQ (because we are using
  674          * APIC for example), then don't bother looking up the BIOS IRQ
  675          * as if we find one it won't be valid anyway.
  676          */
  677         if (!link->l_isa_irq) {
  678                 ACPI_SERIAL_END(pci_link);
  679                 return;
  680         }
  681 
  682         /* Try to find a BIOS IRQ setting from any matching devices. */
  683         bios_irq = acpi_pci_link_search_irq(bus, slot, pin);
  684         if (!PCI_INTERRUPT_VALID(bios_irq)) {
  685                 ACPI_SERIAL_END(pci_link);
  686                 return;
  687         }
  688 
  689         /* Validate the BIOS IRQ. */
  690         if (!link_valid_irq(link, bios_irq)) {
  691                 device_printf(dev, "BIOS IRQ %u for %d.%d.INT%c is invalid\n",
  692                     bios_irq, (int)bus, slot, pin + 'A');
  693         } else if (!PCI_INTERRUPT_VALID(link->l_bios_irq)) {
  694                 link->l_bios_irq = bios_irq;
  695                 if (bios_irq < NUM_ISA_INTERRUPTS)
  696                         pci_link_bios_isa_irqs |= (1 << bios_irq);
  697                 if (bios_irq != link->l_initial_irq &&
  698                     PCI_INTERRUPT_VALID(link->l_initial_irq))
  699                         device_printf(dev,
  700                             "BIOS IRQ %u does not match initial IRQ %u\n",
  701                             bios_irq, link->l_initial_irq);
  702         } else if (bios_irq != link->l_bios_irq)
  703                 device_printf(dev,
  704             "BIOS IRQ %u for %d.%d.INT%c does not match previous BIOS IRQ %u\n",
  705                     bios_irq, (int)bus, slot, pin + 'A',
  706                     link->l_bios_irq);
  707         ACPI_SERIAL_END(pci_link);
  708 }
  709 
  710 static ACPI_STATUS
  711 acpi_pci_link_srs_from_crs(struct acpi_pci_link_softc *sc, ACPI_BUFFER *srsbuf)
  712 {
  713         ACPI_RESOURCE *end, *res;
  714         ACPI_STATUS status;
  715         struct link *link;
  716         int i, in_dpf;
  717 
  718         /* Fetch the _CRS. */
  719         ACPI_SERIAL_ASSERT(pci_link);
  720         srsbuf->Pointer = NULL;
  721         srsbuf->Length = ACPI_ALLOCATE_BUFFER;
  722         status = AcpiGetCurrentResources(acpi_get_handle(sc->pl_dev), srsbuf);
  723         if (ACPI_SUCCESS(status) && srsbuf->Pointer == NULL)
  724                 status = AE_NO_MEMORY;
  725         if (ACPI_FAILURE(status)) {
  726                 if (bootverbose)
  727                         device_printf(sc->pl_dev,
  728                             "Unable to fetch current resources: %s\n",
  729                             AcpiFormatException(status));
  730                 return (status);
  731         }
  732 
  733         /* Fill in IRQ resources via link structures. */
  734         link = sc->pl_links;
  735         i = 0;
  736         in_dpf = DPF_OUTSIDE;
  737         res = (ACPI_RESOURCE *)srsbuf->Pointer;
  738         end = (ACPI_RESOURCE *)((char *)srsbuf->Pointer + srsbuf->Length);
  739         for (;;) {
  740                 switch (res->Type) {
  741                 case ACPI_RESOURCE_TYPE_START_DEPENDENT:
  742                         switch (in_dpf) {
  743                         case DPF_OUTSIDE:
  744                                 /* We've started the first DPF. */
  745                                 in_dpf = DPF_FIRST;
  746                                 break;
  747                         case DPF_FIRST:
  748                                 /* We've started the second DPF. */
  749                                 panic(
  750                 "%s: Multiple dependent functions within a current resource",
  751                                     __func__);
  752                                 break;
  753                         }
  754                         break;
  755                 case ACPI_RESOURCE_TYPE_END_DEPENDENT:
  756                         /* We are finished with DPF parsing. */
  757                         KASSERT(in_dpf != DPF_OUTSIDE,
  758                             ("%s: end dpf when not parsing a dpf", __func__));
  759                         in_dpf = DPF_OUTSIDE;
  760                         break;
  761                 case ACPI_RESOURCE_TYPE_IRQ:
  762                         MPASS(i < sc->pl_num_links);
  763                         res->Data.Irq.InterruptCount = 1;
  764                         if (PCI_INTERRUPT_VALID(link->l_irq)) {
  765                                 KASSERT(link->l_irq < NUM_ISA_INTERRUPTS,
  766                 ("%s: can't put non-ISA IRQ %d in legacy IRQ resource type",
  767                                     __func__, link->l_irq));
  768                                 res->Data.Irq.Interrupts[0] = link->l_irq;
  769                         } else
  770                                 res->Data.Irq.Interrupts[0] = 0;
  771                         link++;
  772                         i++;
  773                         break;
  774                 case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
  775                         MPASS(i < sc->pl_num_links);
  776                         res->Data.ExtendedIrq.InterruptCount = 1;
  777                         if (PCI_INTERRUPT_VALID(link->l_irq))
  778                                 res->Data.ExtendedIrq.Interrupts[0] =
  779                                     link->l_irq;
  780                         else
  781                                 res->Data.ExtendedIrq.Interrupts[0] = 0;
  782                         link++;
  783                         i++;
  784                         break;
  785                 }
  786                 if (res->Type == ACPI_RESOURCE_TYPE_END_TAG)
  787                         break;
  788                 res = ACPI_NEXT_RESOURCE(res);
  789                 if (res >= end)
  790                         break;
  791         }
  792         return (AE_OK);
  793 }
  794 
  795 static ACPI_STATUS
  796 acpi_pci_link_srs_from_links(struct acpi_pci_link_softc *sc,
  797     ACPI_BUFFER *srsbuf)
  798 {
  799         ACPI_RESOURCE newres;
  800         ACPI_STATUS status;
  801         struct link *link;
  802         int i;
  803 
  804         /* Start off with an empty buffer. */
  805         srsbuf->Pointer = NULL;
  806         link = sc->pl_links;
  807         for (i = 0; i < sc->pl_num_links; i++) {
  808 
  809                 /* Add a new IRQ resource from each link. */
  810                 link = &sc->pl_links[i];
  811                 if (link->l_prs_template.Type == ACPI_RESOURCE_TYPE_IRQ) {
  812 
  813                         /* Build an IRQ resource. */
  814                         bcopy(&link->l_prs_template, &newres,
  815                             ACPI_RS_SIZE(newres.Data.Irq));
  816                         newres.Data.Irq.InterruptCount = 1;
  817                         if (PCI_INTERRUPT_VALID(link->l_irq)) {
  818                                 KASSERT(link->l_irq < NUM_ISA_INTERRUPTS,
  819                 ("%s: can't put non-ISA IRQ %d in legacy IRQ resource type",
  820                                     __func__, link->l_irq));
  821                                 newres.Data.Irq.Interrupts[0] = link->l_irq;
  822                         } else
  823                                 newres.Data.Irq.Interrupts[0] = 0;
  824                 } else {
  825 
  826                         /* Build an ExtIRQ resuorce. */
  827                         bcopy(&link->l_prs_template, &newres,
  828                             ACPI_RS_SIZE(newres.Data.ExtendedIrq));
  829                         newres.Data.ExtendedIrq.InterruptCount = 1;
  830                         if (PCI_INTERRUPT_VALID(link->l_irq))
  831                                 newres.Data.ExtendedIrq.Interrupts[0] =
  832                                     link->l_irq;
  833                         else
  834                                 newres.Data.ExtendedIrq.Interrupts[0] = 0;
  835                 }
  836 
  837                 /* Add the new resource to the end of the _SRS buffer. */
  838                 status = acpi_AppendBufferResource(srsbuf, &newres);
  839                 if (ACPI_FAILURE(status)) {
  840                         device_printf(sc->pl_dev,
  841                             "Unable to build resources: %s\n",
  842                             AcpiFormatException(status));
  843                         if (srsbuf->Pointer != NULL)
  844                                 AcpiOsFree(srsbuf->Pointer);
  845                         return (status);
  846                 }
  847         }
  848         return (AE_OK);
  849 }
  850 
  851 static ACPI_STATUS
  852 acpi_pci_link_route_irqs(device_t dev)
  853 {
  854         struct acpi_pci_link_softc *sc;
  855         ACPI_RESOURCE *resource, *end;
  856         ACPI_BUFFER srsbuf;
  857         ACPI_STATUS status;
  858         struct link *link;
  859         int i;
  860 
  861         ACPI_SERIAL_ASSERT(pci_link);
  862         sc = device_get_softc(dev);
  863         if (sc->pl_crs_bad)
  864                 status = acpi_pci_link_srs_from_links(sc, &srsbuf);
  865         else
  866                 status = acpi_pci_link_srs_from_crs(sc, &srsbuf);
  867 
  868         /* Write out new resources via _SRS. */
  869         status = AcpiSetCurrentResources(acpi_get_handle(dev), &srsbuf);
  870         if (ACPI_FAILURE(status)) {
  871                 device_printf(dev, "Unable to route IRQs: %s\n",
  872                     AcpiFormatException(status));
  873                 AcpiOsFree(srsbuf.Pointer);
  874                 return (status);
  875         }
  876 
  877         /*
  878          * Perform acpi_config_intr() on each IRQ resource if it was just
  879          * routed for the first time.
  880          */
  881         link = sc->pl_links;
  882         i = 0;
  883         resource = (ACPI_RESOURCE *)srsbuf.Pointer;
  884         end = (ACPI_RESOURCE *)((char *)srsbuf.Pointer + srsbuf.Length);
  885         for (;;) {
  886                 if (resource->Type == ACPI_RESOURCE_TYPE_END_TAG)
  887                         break;
  888                 switch (resource->Type) {
  889                 case ACPI_RESOURCE_TYPE_IRQ:
  890                 case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
  891                         MPASS(i < sc->pl_num_links);
  892 
  893                         /*
  894                          * Only configure the interrupt and update the
  895                          * weights if this link has a valid IRQ and was
  896                          * previously unrouted.
  897                          */
  898                         if (!link->l_routed &&
  899                             PCI_INTERRUPT_VALID(link->l_irq)) {
  900                                 link->l_routed = TRUE;
  901                                 acpi_config_intr(dev, resource);
  902                                 pci_link_interrupt_weights[link->l_irq] +=
  903                                     link->l_references;
  904                         }
  905                         link++;
  906                         i++;
  907                         break;
  908                 }
  909                 resource = ACPI_NEXT_RESOURCE(resource);
  910                 if (resource >= end)
  911                         break;
  912         }
  913         AcpiOsFree(srsbuf.Pointer);
  914         return (AE_OK);
  915 }
  916 
  917 static int
  918 acpi_pci_link_resume(device_t dev)
  919 {
  920         struct acpi_pci_link_softc *sc;
  921         ACPI_STATUS status;
  922         int i, routed;
  923 
  924         /*
  925          * If all of our links are routed, then restore the link via _SRS,
  926          * otherwise, disable the link via _DIS.
  927          */
  928         ACPI_SERIAL_BEGIN(pci_link);
  929         sc = device_get_softc(dev);
  930         routed = 0;
  931         for (i = 0; i < sc->pl_num_links; i++)
  932                 if (sc->pl_links[i].l_routed)
  933                         routed++;
  934         if (routed == sc->pl_num_links)
  935                 status = acpi_pci_link_route_irqs(dev);
  936         else {
  937                 AcpiEvaluateObject(acpi_get_handle(dev), "_DIS", NULL, NULL);
  938                 status = AE_OK;
  939         }
  940         ACPI_SERIAL_END(pci_link);
  941         if (ACPI_FAILURE(status))
  942                 return (ENXIO);
  943         else
  944                 return (0);
  945 }
  946 
  947 /*
  948  * Pick an IRQ to use for this unrouted link.
  949  */
  950 static uint8_t
  951 acpi_pci_link_choose_irq(device_t dev, struct link *link)
  952 {
  953         char tunable_buffer[64], link_name[5];
  954         u_int8_t best_irq, pos_irq;
  955         int best_weight, pos_weight, i;
  956 
  957         KASSERT(!link->l_routed, ("%s: link already routed", __func__));
  958         KASSERT(!PCI_INTERRUPT_VALID(link->l_irq),
  959             ("%s: link already has an IRQ", __func__));
  960 
  961         /* Check for a tunable override. */
  962         if (ACPI_SUCCESS(acpi_short_name(acpi_get_handle(dev), link_name,
  963             sizeof(link_name)))) {
  964                 snprintf(tunable_buffer, sizeof(tunable_buffer),
  965                     "hw.pci.link.%s.%d.irq", link_name, link->l_res_index);
  966                 if (getenv_int(tunable_buffer, &i) && PCI_INTERRUPT_VALID(i)) {
  967                         if (!link_valid_irq(link, i))
  968                                 device_printf(dev,
  969                                     "Warning, IRQ %d is not listed as valid\n",
  970                                     i);
  971                         return (i);
  972                 }
  973                 snprintf(tunable_buffer, sizeof(tunable_buffer),
  974                     "hw.pci.link.%s.irq", link_name);
  975                 if (getenv_int(tunable_buffer, &i) && PCI_INTERRUPT_VALID(i)) {
  976                         if (!link_valid_irq(link, i))
  977                                 device_printf(dev,
  978                                     "Warning, IRQ %d is not listed as valid\n",
  979                                     i);
  980                         return (i);
  981                 }
  982         }
  983 
  984         /*
  985          * If we have a valid BIOS IRQ, use that.  We trust what the BIOS
  986          * says it routed over what _CRS says the link thinks is routed.
  987          */
  988         if (PCI_INTERRUPT_VALID(link->l_bios_irq))
  989                 return (link->l_bios_irq);
  990 
  991         /*
  992          * If we don't have a BIOS IRQ but do have a valid IRQ from _CRS,
  993          * then use that.
  994          */
  995         if (PCI_INTERRUPT_VALID(link->l_initial_irq))
  996                 return (link->l_initial_irq);
  997 
  998         /*
  999          * Ok, we have no useful hints, so we have to pick from the
 1000          * possible IRQs.  For ISA IRQs we only use interrupts that
 1001          * have already been used by the BIOS.
 1002          */
 1003         best_irq = PCI_INVALID_IRQ;
 1004         best_weight = INT_MAX;
 1005         for (i = 0; i < link->l_num_irqs; i++) {
 1006                 pos_irq = link->l_irqs[i];
 1007                 if (pos_irq < NUM_ISA_INTERRUPTS &&
 1008                     (pci_link_bios_isa_irqs & 1 << pos_irq) == 0)
 1009                         continue;
 1010                 pos_weight = pci_link_interrupt_weights[pos_irq];
 1011                 if (pos_weight < best_weight) {
 1012                         best_weight = pos_weight;
 1013                         best_irq = pos_irq;
 1014                 }
 1015         }
 1016 
 1017         /*
 1018          * If this is an ISA IRQ, try using the SCI if it is also an ISA
 1019          * interrupt as a fallback.
 1020          */
 1021         if (link->l_isa_irq) {
 1022                 pos_irq = AcpiGbl_FADT.SciInterrupt;
 1023                 pos_weight = pci_link_interrupt_weights[pos_irq];
 1024                 if (pos_weight < best_weight) {
 1025                         best_weight = pos_weight;
 1026                         best_irq = pos_irq;
 1027                 }
 1028         }
 1029 
 1030         if (PCI_INTERRUPT_VALID(best_irq)) {
 1031                 if (bootverbose)
 1032                         device_printf(dev, "Picked IRQ %u with weight %d\n",
 1033                             best_irq, best_weight);
 1034         } else
 1035                 device_printf(dev, "Unable to choose an IRQ\n");
 1036         return (best_irq);
 1037 }
 1038 
 1039 int
 1040 acpi_pci_link_route_interrupt(device_t dev, int index)
 1041 {
 1042         struct link *link;
 1043 
 1044         if (acpi_disabled("pci_link"))
 1045                 return (PCI_INVALID_IRQ);
 1046 
 1047         ACPI_SERIAL_BEGIN(pci_link);
 1048         link = acpi_pci_link_lookup(dev, index);
 1049         if (link == NULL)
 1050                 panic("%s: apparently invalid index %d", __func__, index);
 1051 
 1052         /*
 1053          * If this link device is already routed to an interrupt, just return
 1054          * the interrupt it is routed to.
 1055          */
 1056         if (link->l_routed) {
 1057                 KASSERT(PCI_INTERRUPT_VALID(link->l_irq),
 1058                     ("%s: link is routed but has an invalid IRQ", __func__));
 1059                 ACPI_SERIAL_END(pci_link);
 1060                 return (link->l_irq);
 1061         }
 1062 
 1063         /* Choose an IRQ if we need one. */
 1064         if (!PCI_INTERRUPT_VALID(link->l_irq)) {
 1065                 link->l_irq = acpi_pci_link_choose_irq(dev, link);
 1066 
 1067                 /*
 1068                  * Try to route the interrupt we picked.  If it fails, then
 1069                  * assume the interrupt is not routed.
 1070                  */
 1071                 if (PCI_INTERRUPT_VALID(link->l_irq)) {
 1072                         acpi_pci_link_route_irqs(dev);
 1073                         if (!link->l_routed)
 1074                                 link->l_irq = PCI_INVALID_IRQ;
 1075                 }
 1076         }
 1077         ACPI_SERIAL_END(pci_link);
 1078 
 1079         return (link->l_irq);
 1080 }
 1081 
 1082 /*
 1083  * This is gross, but we abuse the identify routine to perform one-time
 1084  * SYSINIT() style initialization for the driver.
 1085  */
 1086 static void
 1087 acpi_pci_link_identify(driver_t *driver, device_t parent)
 1088 {
 1089 
 1090         /*
 1091          * If the SCI is an ISA IRQ, add it to the bitmask of known good
 1092          * ISA IRQs.
 1093          *
 1094          * XXX: If we are using the APIC, the SCI might have been
 1095          * rerouted to an APIC pin in which case this is invalid.  However,
 1096          * if we are using the APIC, we also shouldn't be having any PCI
 1097          * interrupts routed via ISA IRQs, so this is probably ok.
 1098          */
 1099         if (AcpiGbl_FADT.SciInterrupt < NUM_ISA_INTERRUPTS)
 1100                 pci_link_bios_isa_irqs |= (1 << AcpiGbl_FADT.SciInterrupt);
 1101 }
 1102 
 1103 static device_method_t acpi_pci_link_methods[] = {
 1104         /* Device interface */
 1105         DEVMETHOD(device_identify,      acpi_pci_link_identify),
 1106         DEVMETHOD(device_probe,         acpi_pci_link_probe),
 1107         DEVMETHOD(device_attach,        acpi_pci_link_attach),
 1108         DEVMETHOD(device_resume,        acpi_pci_link_resume),
 1109 
 1110         DEVMETHOD_END
 1111 };
 1112 
 1113 static driver_t acpi_pci_link_driver = {
 1114         "pci_link",
 1115         acpi_pci_link_methods,
 1116         sizeof(struct acpi_pci_link_softc),
 1117 };
 1118 
 1119 static devclass_t pci_link_devclass;
 1120 
 1121 DRIVER_MODULE(acpi_pci_link, acpi, acpi_pci_link_driver, pci_link_devclass, 0,
 1122     0);
 1123 MODULE_DEPEND(acpi_pci_link, acpi, 1, 1, 1);

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