The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/i386/pci/pci_pir.c

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    1 /*-
    2  * Copyright (c) 1997, Stefan Esser <se@freebsd.org>
    3  * Copyright (c) 2000, Michael Smith <msmith@freebsd.org>
    4  * Copyright (c) 2000, BSDi
    5  * Copyright (c) 2004, John Baldwin <jhb@FreeBSD.org>
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice unmodified, this list of conditions, and the following
   13  *    disclaimer.
   14  * 2. Redistributions in binary form must reproduce the above copyright
   15  *    notice, this list of conditions and the following disclaimer in the
   16  *    documentation and/or other materials provided with the distribution.
   17  *
   18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD: releng/6.2/sys/i386/pci/pci_pir.c 148129 2005-07-18 19:45:21Z jhb $");
   32 
   33 #include <sys/param.h>
   34 #include <sys/systm.h>
   35 #include <sys/bus.h>
   36 #include <sys/kernel.h>
   37 #include <sys/malloc.h>
   38 #include <sys/module.h>
   39 #include <sys/sysctl.h>
   40 #include <vm/vm.h>
   41 #include <vm/pmap.h>
   42 #include <vm/vm_param.h>
   43 #include <machine/md_var.h>
   44 #include <dev/pci/pcivar.h>
   45 #include <dev/pci/pcireg.h>
   46 #include <machine/pci_cfgreg.h>
   47 #include <machine/segments.h>
   48 #include <machine/pc/bios.h>
   49 
   50 #define NUM_ISA_INTERRUPTS      16
   51 
   52 /*
   53  * A link device.  Loosely based on the ACPI PCI link device.  This doesn't
   54  * try to support priorities for different ISA interrupts.
   55  */
   56 struct pci_link {
   57         TAILQ_ENTRY(pci_link) pl_links;
   58         uint8_t         pl_id;
   59         uint8_t         pl_irq;
   60         uint16_t        pl_irqmask;
   61         int             pl_references;
   62         int             pl_routed;
   63 };
   64 
   65 struct pci_link_lookup {
   66         struct pci_link **pci_link_ptr;
   67         int             bus;
   68         int             device;
   69         int             pin;
   70 };
   71 
   72 struct pci_dev_lookup {
   73         uint8_t         link;
   74         int             bus;
   75         int             device;
   76         int             pin;
   77 };
   78 
   79 typedef void pir_entry_handler(struct PIR_entry *entry,
   80     struct PIR_intpin* intpin, void *arg);
   81 
   82 static void     pci_print_irqmask(u_int16_t irqs);
   83 static int      pci_pir_biosroute(int bus, int device, int func, int pin,
   84                     int irq);
   85 static int      pci_pir_choose_irq(struct pci_link *pci_link, int irqmask);
   86 static void     pci_pir_create_links(struct PIR_entry *entry,
   87                     struct PIR_intpin *intpin, void *arg);
   88 static void     pci_pir_dump_links(void);
   89 static struct pci_link *pci_pir_find_link(uint8_t link_id);
   90 static void     pci_pir_find_link_handler(struct PIR_entry *entry,
   91                     struct PIR_intpin *intpin, void *arg);
   92 static void     pci_pir_initial_irqs(struct PIR_entry *entry,
   93                     struct PIR_intpin *intpin, void *arg);
   94 static void     pci_pir_parse(void);
   95 static void     pci_pir_print_intpin(struct PIR_entry *entry,
   96                     struct PIR_intpin *intpin, void *arg);
   97 static void     pci_pir_print_table(void);
   98 static uint8_t  pci_pir_search_irq(int bus, int device, int pin);
   99 static int      pci_pir_valid_irq(struct pci_link *pci_link, int irq);
  100 static void     pci_pir_walk_table(pir_entry_handler *handler, void *arg);
  101 
  102 static MALLOC_DEFINE(M_PIR, "$PIR", "$PIR structures");
  103 
  104 static struct PIR_table *pci_route_table;
  105 static device_t pir_device;
  106 static int pci_route_count, pir_bios_irqs, pir_parsed;
  107 static TAILQ_HEAD(, pci_link) pci_links;
  108 static int pir_interrupt_weight[NUM_ISA_INTERRUPTS];
  109 
  110 /* sysctl vars */
  111 SYSCTL_DECL(_hw_pci);
  112 
  113 #ifdef PC98
  114 /* IRQs 3, 5, 7, 9, 10, 11, 12, 13 */
  115 #define PCI_IRQ_OVERRIDE_MASK 0x3e68
  116 #else
  117 /* IRQs 3, 4, 5, 6, 7, 9, 10, 11, 12, 14, 15 */
  118 #define PCI_IRQ_OVERRIDE_MASK 0xdef8
  119 #endif
  120 
  121 static uint32_t pci_irq_override_mask = PCI_IRQ_OVERRIDE_MASK;
  122 TUNABLE_INT("hw.pci.irq_override_mask", &pci_irq_override_mask);
  123 SYSCTL_INT(_hw_pci, OID_AUTO, irq_override_mask, CTLFLAG_RDTUN,
  124     &pci_irq_override_mask, PCI_IRQ_OVERRIDE_MASK,
  125     "Mask of allowed irqs to try to route when it has no good clue about\n"
  126     "which irqs it should use.");
  127 
  128 /*
  129  * Look for the interrupt routing table.
  130  *
  131  * We use PCI BIOS's PIR table if it's available. $PIR is the standard way
  132  * to do this.  Sadly, some machines are not standards conforming and have
  133  * _PIR instead.  We shrug and cope by looking for both.
  134  */
  135 void
  136 pci_pir_open(void)
  137 {
  138         struct PIR_table *pt;
  139         uint32_t sigaddr;
  140         int i;
  141         uint8_t ck, *cv;
  142 
  143         /* Don't try if we've already found a table. */
  144         if (pci_route_table != NULL)
  145                 return;
  146 
  147         /* Look for $PIR and then _PIR. */
  148         sigaddr = bios_sigsearch(0, "$PIR", 4, 16, 0);
  149         if (sigaddr == 0)
  150                 sigaddr = bios_sigsearch(0, "_PIR", 4, 16, 0);
  151         if (sigaddr == 0)
  152                 return;
  153 
  154         /* If we found something, check the checksum and length. */
  155         /* XXX - Use pmap_mapdev()? */
  156         pt = (struct PIR_table *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
  157         if (pt->pt_header.ph_length <= sizeof(struct PIR_header))
  158                 return;
  159         for (cv = (u_int8_t *)pt, ck = 0, i = 0;
  160              i < (pt->pt_header.ph_length); i++)
  161                 ck += cv[i];
  162         if (ck != 0)
  163                 return;
  164 
  165         /* Ok, we've got a valid table. */
  166         pci_route_table = pt;
  167         pci_route_count = (pt->pt_header.ph_length -
  168             sizeof(struct PIR_header)) / 
  169             sizeof(struct PIR_entry);
  170         if (bootverbose) {
  171                 printf("Found $PIR table, %d entries at %p\n",
  172                     pci_route_count, pci_route_table);
  173                 pci_pir_print_table();
  174         }
  175 }
  176 
  177 /*
  178  * Find the pci_link structure for a given link ID.
  179  */
  180 static struct pci_link *
  181 pci_pir_find_link(uint8_t link_id)
  182 {
  183         struct pci_link *pci_link;
  184 
  185         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  186                 if (pci_link->pl_id == link_id)
  187                         return (pci_link);
  188         }
  189         return (NULL);
  190 }
  191 
  192 /*
  193  * Find the link device associated with a PCI device in the table.
  194  */
  195 static void
  196 pci_pir_find_link_handler(struct PIR_entry *entry, struct PIR_intpin *intpin,
  197     void *arg)
  198 {
  199         struct pci_link_lookup *lookup;
  200 
  201         lookup = (struct pci_link_lookup *)arg;
  202         if (entry->pe_bus == lookup->bus &&
  203             entry->pe_device == lookup->device &&
  204             intpin - entry->pe_intpin == lookup->pin)
  205                 *lookup->pci_link_ptr = pci_pir_find_link(intpin->link);
  206 }
  207 
  208 /*
  209  * Check to see if a possible IRQ setting is valid.
  210  */
  211 static int
  212 pci_pir_valid_irq(struct pci_link *pci_link, int irq)
  213 {
  214 
  215         if (!PCI_INTERRUPT_VALID(irq))
  216                 return (0);
  217         return (pci_link->pl_irqmask & (1 << irq));
  218 }
  219 
  220 /*
  221  * Walk the $PIR executing the worker function for each valid intpin entry
  222  * in the table.  The handler is passed a pointer to both the entry and
  223  * the intpin in the entry.
  224  */
  225 static void
  226 pci_pir_walk_table(pir_entry_handler *handler, void *arg)
  227 {
  228         struct PIR_entry *entry;
  229         struct PIR_intpin *intpin;
  230         int i, pin;
  231 
  232         entry = &pci_route_table->pt_entry[0];
  233         for (i = 0; i < pci_route_count; i++, entry++) {
  234                 intpin = &entry->pe_intpin[0];
  235                 for (pin = 0; pin < 4; pin++, intpin++)
  236                         if (intpin->link != 0)
  237                                 handler(entry, intpin, arg);
  238         }
  239 }
  240 
  241 static void
  242 pci_pir_create_links(struct PIR_entry *entry, struct PIR_intpin *intpin,
  243     void *arg)
  244 {
  245         struct pci_link *pci_link;
  246 
  247         pci_link = pci_pir_find_link(intpin->link);
  248         if (pci_link != NULL) {
  249                 pci_link->pl_references++;
  250                 if (intpin->irqs != pci_link->pl_irqmask) {
  251                         if (bootverbose)
  252                                 printf(
  253         "$PIR: Entry %d.%d.INT%c has different mask for link %#x, merging\n",
  254                                     entry->pe_bus, entry->pe_device,
  255                                     (intpin - entry->pe_intpin) + 'A',
  256                                     pci_link->pl_id);
  257                         pci_link->pl_irqmask &= intpin->irqs;
  258                 }
  259         } else {
  260                 pci_link = malloc(sizeof(struct pci_link), M_PIR, M_WAITOK);
  261                 pci_link->pl_id = intpin->link;
  262                 pci_link->pl_irqmask = intpin->irqs;
  263                 pci_link->pl_irq = PCI_INVALID_IRQ;
  264                 pci_link->pl_references = 1;
  265                 pci_link->pl_routed = 0;
  266                 TAILQ_INSERT_TAIL(&pci_links, pci_link, pl_links);
  267         }
  268 }
  269 
  270 /*
  271  * Look to see if any of the function on the PCI device at bus/device have
  272  * an interrupt routed to intpin 'pin' by the BIOS.
  273  */
  274 static uint8_t
  275 pci_pir_search_irq(int bus, int device, int pin)
  276 {
  277         uint32_t value;
  278         uint8_t func, maxfunc;
  279 
  280         /* See if we have a valid device at function 0. */
  281         value = pci_cfgregread(bus, device, 0, PCIR_HDRTYPE, 1);
  282         if ((value & PCIM_HDRTYPE) > PCI_MAXHDRTYPE)
  283                 return (PCI_INVALID_IRQ);
  284         if (value & PCIM_MFDEV)
  285                 maxfunc = PCI_FUNCMAX;
  286         else
  287                 maxfunc = 0;
  288 
  289         /* Scan all possible functions at this device. */
  290         for (func = 0; func <= maxfunc; func++) {
  291                 value = pci_cfgregread(bus, device, func, PCIR_DEVVENDOR, 4);
  292                 if (value == 0xffffffff)
  293                         continue;
  294                 value = pci_cfgregread(bus, device, func, PCIR_INTPIN, 1);
  295 
  296                 /*
  297                  * See if it uses the pin in question.  Note that the passed
  298                  * in pin uses 0 for A, .. 3 for D whereas the intpin
  299                  * register uses 0 for no interrupt, 1 for A, .. 4 for D.
  300                  */
  301                 if (value != pin + 1)
  302                         continue;
  303                 value = pci_cfgregread(bus, device, func, PCIR_INTLINE, 1);
  304                 if (bootverbose)
  305                         printf(
  306                 "$PIR: Found matching pin for %d.%d.INT%c at func %d: %d\n",
  307                             bus, device, pin + 'A', func, value);
  308                 if (value != PCI_INVALID_IRQ)
  309                         return (value);
  310         }
  311         return (PCI_INVALID_IRQ);
  312 }
  313 
  314 /*
  315  * Try to initialize IRQ based on this device's IRQ.
  316  */
  317 static void
  318 pci_pir_initial_irqs(struct PIR_entry *entry, struct PIR_intpin *intpin,
  319     void *arg)
  320 {
  321         struct pci_link *pci_link;
  322         uint8_t irq, pin;
  323 
  324         pin = intpin - entry->pe_intpin;
  325         pci_link = pci_pir_find_link(intpin->link);
  326         irq = pci_pir_search_irq(entry->pe_bus, entry->pe_device, pin);
  327         if (irq == PCI_INVALID_IRQ || irq == pci_link->pl_irq)
  328                 return;
  329 
  330         /* Don't trust any BIOS IRQs greater than 15. */
  331         if (irq >= NUM_ISA_INTERRUPTS) {
  332                 printf(
  333         "$PIR: Ignoring invalid BIOS IRQ %d from %d.%d.INT%c for link %#x\n",
  334                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  335                     pci_link->pl_id);
  336                 return;
  337         }
  338 
  339         /*
  340          * If we don't have an IRQ for this link yet, then we trust the
  341          * BIOS, even if it seems invalid from the $PIR entries.
  342          */
  343         if (pci_link->pl_irq == PCI_INVALID_IRQ) {
  344                 if (!pci_pir_valid_irq(pci_link, irq))
  345                         printf(
  346         "$PIR: Using invalid BIOS IRQ %d from %d.%d.INT%c for link %#x\n",
  347                             irq, entry->pe_bus, entry->pe_device, pin + 'A',
  348                             pci_link->pl_id);
  349                 pci_link->pl_irq = irq;
  350                 pci_link->pl_routed = 1;
  351                 return;
  352         }
  353 
  354         /*
  355          * We have an IRQ and it doesn't match the current IRQ for this
  356          * link.  If the new IRQ is invalid, then warn about it and ignore
  357          * it.  If the old IRQ is invalid and the new IRQ is valid, then
  358          * prefer the new IRQ instead.  If both IRQs are valid, then just
  359          * use the first one.  Note that if we ever get into this situation
  360          * we are having to guess which setting the BIOS actually routed.
  361          * Perhaps we should just give up instead.
  362          */
  363         if (!pci_pir_valid_irq(pci_link, irq)) {
  364                 printf(
  365                 "$PIR: BIOS IRQ %d for %d.%d.INT%c is not valid for link %#x\n",
  366                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  367                     pci_link->pl_id);
  368         } else if (!pci_pir_valid_irq(pci_link, pci_link->pl_irq)) {
  369                 printf(
  370 "$PIR: Preferring valid BIOS IRQ %d from %d.%d.INT%c for link %#x to IRQ %d\n", 
  371                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  372                     pci_link->pl_id, pci_link->pl_irq);
  373                 pci_link->pl_irq = irq;
  374                 pci_link->pl_routed = 1;
  375         } else
  376                 printf(
  377         "$PIR: BIOS IRQ %d for %d.%d.INT%c does not match link %#x irq %d\n",
  378                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  379                     pci_link->pl_id, pci_link->pl_irq);
  380 }
  381 
  382 /*
  383  * Parse $PIR to enumerate link devices and attempt to determine their
  384  * initial state.  This could perhaps be cleaner if we had drivers for the
  385  * various interrupt routers as they could read the initial IRQ for each
  386  * link.
  387  */
  388 static void
  389 pci_pir_parse(void)
  390 {
  391         char tunable_buffer[64];
  392         struct pci_link *pci_link;
  393         int i, irq;
  394 
  395         /* Only parse once. */
  396         if (pir_parsed)
  397                 return;
  398         pir_parsed = 1;
  399 
  400         /* Enumerate link devices. */
  401         TAILQ_INIT(&pci_links);
  402         pci_pir_walk_table(pci_pir_create_links, NULL);
  403         if (bootverbose) {
  404                 printf("$PIR: Links after initial probe:\n");
  405                 pci_pir_dump_links();
  406         }
  407 
  408         /* Check for unique IRQ masks. */
  409         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  410                 if (pci_link->pl_irqmask != 0 && powerof2(pci_link->pl_irqmask))
  411                         pci_link->pl_irq = ffs(pci_link->pl_irqmask) - 1;
  412         }
  413 
  414         /*
  415          * Check to see if the BIOS has already routed any of the links by
  416          * checking each device connected to each link to see if it has a
  417          * valid IRQ.
  418          */
  419         pci_pir_walk_table(pci_pir_initial_irqs, NULL);
  420         if (bootverbose) {
  421                 printf("$PIR: Links after initial IRQ discovery:\n");
  422                 pci_pir_dump_links();
  423         }
  424 
  425         /*
  426          * Allow the user to override the IRQ for a given link device.  We
  427          * allow invalid IRQs to be specified but warn about them.  An IRQ
  428          * of 255 or 0 clears any preset IRQ.
  429          */
  430         i = 0;
  431         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  432                 snprintf(tunable_buffer, sizeof(tunable_buffer),
  433                     "hw.pci.link.%#x.irq", pci_link->pl_id);
  434                 if (getenv_int(tunable_buffer, &irq) == 0)
  435                         continue;
  436                 if (irq == 0)
  437                         irq = PCI_INVALID_IRQ;
  438                 if (irq != PCI_INVALID_IRQ &&
  439                     !pci_pir_valid_irq(pci_link, irq) && bootverbose)
  440                         printf(
  441                 "$PIR: Warning, IRQ %d for link %#x is not listed as valid\n",
  442                             irq, pci_link->pl_id);
  443                 pci_link->pl_routed = 0;
  444                 pci_link->pl_irq = irq;
  445                 i = 1;
  446         }
  447         if (bootverbose && i) {
  448                 printf("$PIR: Links after tunable overrides:\n");
  449                 pci_pir_dump_links();
  450         }
  451 
  452         /*
  453          * Build initial interrupt weights as well as bitmap of "known-good"
  454          * IRQs that the BIOS has already used for PCI link devices.
  455          */
  456         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  457                 if (!PCI_INTERRUPT_VALID(pci_link->pl_irq))
  458                         continue;
  459                 pir_bios_irqs |= 1 << pci_link->pl_irq;
  460                 pir_interrupt_weight[pci_link->pl_irq] +=
  461                     pci_link->pl_references;
  462         }
  463         if (bootverbose) {
  464                 printf("$PIR: IRQs used by BIOS: ");
  465                 pci_print_irqmask(pir_bios_irqs);
  466                 printf("\n");
  467                 printf("$PIR: Interrupt Weights:\n[ ");
  468                 for (i = 0; i < NUM_ISA_INTERRUPTS; i++)
  469                         printf(" %3d", i);
  470                 printf(" ]\n[ ");
  471                 for (i = 0; i < NUM_ISA_INTERRUPTS; i++)
  472                         printf(" %3d", pir_interrupt_weight[i]);
  473                 printf(" ]\n");
  474         }
  475 }
  476 
  477 /*
  478  * Use the PCI BIOS to route an interrupt for a given device.
  479  *
  480  * Input:
  481  * AX = PCIBIOS_ROUTE_INTERRUPT
  482  * BH = bus
  483  * BL = device [7:3] / function [2:0]
  484  * CH = IRQ
  485  * CL = Interrupt Pin (0x0A = A, ... 0x0D = D)
  486  */
  487 static int
  488 pci_pir_biosroute(int bus, int device, int func, int pin, int irq)
  489 {
  490         struct bios_regs args;
  491 
  492         args.eax = PCIBIOS_ROUTE_INTERRUPT;
  493         args.ebx = (bus << 8) | (device << 3) | func;
  494         args.ecx = (irq << 8) | (0xa + pin);
  495         return (bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL)));
  496 }
  497 
  498 
  499 /*
  500  * Route a PCI interrupt using a link device from the $PIR.
  501  */
  502 int
  503 pci_pir_route_interrupt(int bus, int device, int func, int pin)
  504 {
  505         struct pci_link_lookup lookup;
  506         struct pci_link *pci_link;
  507         int error, irq;
  508 
  509         if (pci_route_table == NULL)
  510                 return (PCI_INVALID_IRQ);
  511 
  512         /* Lookup link device for this PCI device/pin. */
  513         pci_link = NULL;
  514         lookup.bus = bus;
  515         lookup.device = device;
  516         lookup.pin = pin - 1;
  517         lookup.pci_link_ptr = &pci_link;
  518         pci_pir_walk_table(pci_pir_find_link_handler, &lookup);
  519         if (pci_link == NULL) {
  520                 printf("$PIR: No matching entry for %d.%d.INT%c\n", bus,
  521                     device, pin - 1 + 'A');
  522                 return (PCI_INVALID_IRQ);
  523         }
  524 
  525         /*
  526          * Pick a new interrupt if we don't have one already.  We look for
  527          * an interrupt from several different sets.  First, we check the
  528          * set of PCI only interrupts from the $PIR.  Second, we check the
  529          * set of known-good interrupts that the BIOS has already used.
  530          * Lastly, we check the "all possible valid IRQs" set.
  531          */
  532         if (!PCI_INTERRUPT_VALID(pci_link->pl_irq)) {
  533                 irq = pci_pir_choose_irq(pci_link,
  534                     pci_route_table->pt_header.ph_pci_irqs);
  535                 if (!PCI_INTERRUPT_VALID(irq))
  536                         irq = pci_pir_choose_irq(pci_link, pir_bios_irqs);
  537                 if (!PCI_INTERRUPT_VALID(irq))
  538                         irq = pci_pir_choose_irq(pci_link,
  539                             pci_irq_override_mask);
  540                 if (!PCI_INTERRUPT_VALID(irq)) {
  541                         if (bootverbose)
  542                                 printf(
  543                         "$PIR: Failed to route interrupt for %d:%d INT%c\n",
  544                                     bus, device, pin - 1 + 'A');
  545                         return (PCI_INVALID_IRQ);
  546                 }
  547                 pci_link->pl_irq = irq;
  548         }
  549 
  550         /* Ask the BIOS to route this IRQ if we haven't done so already. */
  551         if (!pci_link->pl_routed) {
  552                 error = pci_pir_biosroute(bus, device, func, pin - 1,
  553                     pci_link->pl_irq);
  554 
  555                 /* Ignore errors when routing a unique interrupt. */
  556                 if (error && !powerof2(pci_link->pl_irqmask)) {
  557                         printf("$PIR: ROUTE_INTERRUPT failed.\n");
  558                         return (PCI_INVALID_IRQ);
  559                 }
  560                 pci_link->pl_routed = 1;
  561 
  562                 /* Ensure the interrupt is set to level/low trigger. */
  563                 KASSERT(pir_device != NULL, ("missing pir device"));
  564                 BUS_CONFIG_INTR(pir_device, pci_link->pl_irq,
  565                     INTR_TRIGGER_LEVEL, INTR_POLARITY_LOW);
  566         }
  567         if (bootverbose)
  568                 printf("$PIR: %d:%d INT%c routed to irq %d\n", bus, device,
  569                     pin - 1 + 'A', pci_link->pl_irq);
  570         return (pci_link->pl_irq);
  571 }
  572 
  573 /*
  574  * Try to pick an interrupt for the specified link from the interrupts
  575  * set in the mask.
  576  */
  577 static int
  578 pci_pir_choose_irq(struct pci_link *pci_link, int irqmask)
  579 {
  580         int i, irq, realmask;
  581 
  582         /* XXX: Need to have a #define of known bad IRQs to also mask out? */
  583         realmask = pci_link->pl_irqmask & irqmask;
  584         if (realmask == 0)
  585                 return (PCI_INVALID_IRQ);
  586 
  587         /* Find IRQ with lowest weight. */
  588         irq = PCI_INVALID_IRQ;
  589         for (i = 0; i < NUM_ISA_INTERRUPTS; i++) {
  590                 if (!(realmask & 1 << i))
  591                         continue;
  592                 if (irq == PCI_INVALID_IRQ ||
  593                     pir_interrupt_weight[i] < pir_interrupt_weight[irq])
  594                         irq = i;
  595         }
  596         if (bootverbose && PCI_INTERRUPT_VALID(irq)) {
  597                 printf("$PIR: Found IRQ %d for link %#x from ", irq,
  598                     pci_link->pl_id);
  599                 pci_print_irqmask(realmask);
  600                 printf("\n");
  601         }
  602         return (irq);
  603 }
  604 
  605 static void
  606 pci_print_irqmask(u_int16_t irqs)
  607 {
  608         int i, first;
  609 
  610         if (irqs == 0) {
  611                 printf("none");
  612                 return;
  613         }
  614         first = 1;
  615         for (i = 0; i < 16; i++, irqs >>= 1)
  616                 if (irqs & 1) {
  617                         if (!first)
  618                                 printf(" ");
  619                         else
  620                                 first = 0;
  621                         printf("%d", i);
  622                 }
  623 }
  624 
  625 /*
  626  * Dump the contents of a single intpin entry to the console.
  627  */
  628 static void
  629 pci_pir_print_intpin(struct PIR_entry *entry, struct PIR_intpin *intpin,
  630     void *arg)
  631 {
  632 
  633         if (entry->pe_slot == 0)
  634                 printf("embedded ");
  635         else
  636                 printf("slot %-3d ", entry->pe_slot);
  637         printf(" %3d  %3d    %c   0x%02x  ", entry->pe_bus, entry->pe_device,
  638             intpin - entry->pe_intpin + 'A', intpin->link);
  639         pci_print_irqmask(intpin->irqs);
  640         printf("\n");
  641 }
  642 
  643 /*
  644  * Dump the contents of a PCI BIOS Interrupt Routing Table to the console.
  645  */
  646 static void
  647 pci_pir_print_table(void)
  648 {
  649 
  650         printf("PCI-Only Interrupts: ");
  651         pci_print_irqmask(pci_route_table->pt_header.ph_pci_irqs);
  652         printf("\nLocation  Bus Device Pin  Link  IRQs\n");
  653         pci_pir_walk_table(pci_pir_print_intpin, NULL);
  654 }
  655 
  656 /*
  657  * Display link devices.
  658  */
  659 static void
  660 pci_pir_dump_links(void)
  661 {
  662         struct pci_link *pci_link;
  663 
  664         printf("Link  IRQ  Rtd  Ref  IRQs\n");
  665         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  666                 printf("%#4x  %3d   %c   %3d  ", pci_link->pl_id,
  667                     pci_link->pl_irq, pci_link->pl_routed ? 'Y' : 'N',
  668                     pci_link->pl_references);
  669                 pci_print_irqmask(pci_link->pl_irqmask);
  670                 printf("\n");
  671         }
  672 }
  673 
  674 /*
  675  * See if any interrupts for a given PCI bus are routed in the PIR.  Don't
  676  * even bother looking if the BIOS doesn't support routing anyways.  If we
  677  * are probing a PCI-PCI bridge, then require_parse will be true and we should
  678  * only succeed if a host-PCI bridge has already attached and parsed the PIR.
  679  */
  680 int
  681 pci_pir_probe(int bus, int require_parse)
  682 {
  683         int i;
  684 
  685         if (pci_route_table == NULL || (require_parse && !pir_parsed))
  686                 return (0);
  687         for (i = 0; i < pci_route_count; i++)
  688                 if (pci_route_table->pt_entry[i].pe_bus == bus)
  689                         return (1);
  690         return (0);
  691 }
  692 
  693 /*
  694  * The driver for the new-bus psuedo device pir0 for the $PIR table.
  695  */
  696 
  697 static int
  698 pir_probe(device_t dev)
  699 {
  700         char buf[64];
  701 
  702         snprintf(buf, sizeof(buf), "PCI Interrupt Routing Table: %d Entries",
  703             pci_route_count);
  704         device_set_desc_copy(dev, buf);
  705         return (0);
  706 }
  707 
  708 static int
  709 pir_attach(device_t dev)
  710 {
  711 
  712         pci_pir_parse();
  713         KASSERT(pir_device == NULL, ("Multiple pir devices"));
  714         pir_device = dev;
  715         return (0);
  716 }
  717 
  718 static void
  719 pir_resume_find_device(struct PIR_entry *entry, struct PIR_intpin *intpin,
  720     void *arg)
  721 {
  722         struct pci_dev_lookup *pd;
  723 
  724         pd = (struct pci_dev_lookup *)arg;
  725         if (intpin->link != pd->link || pd->bus != -1)
  726                 return;
  727         pd->bus = entry->pe_bus;
  728         pd->device = entry->pe_device;
  729         pd->pin = intpin - entry->pe_intpin;
  730 }
  731 
  732 static int
  733 pir_resume(device_t dev)
  734 {
  735         struct pci_dev_lookup pd;
  736         struct pci_link *pci_link;
  737         int error;
  738 
  739         /* Ask the BIOS to re-route each link that was already routed. */
  740         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  741                 if (!PCI_INTERRUPT_VALID(pci_link->pl_irq)) {
  742                         KASSERT(!pci_link->pl_routed,
  743                             ("link %#x is routed but has invalid PCI IRQ",
  744                             pci_link->pl_id));
  745                         continue;
  746                 }
  747                 if (pci_link->pl_routed) {
  748                         pd.bus = -1;
  749                         pd.link = pci_link->pl_id;
  750                         pci_pir_walk_table(pir_resume_find_device, &pd);
  751                         KASSERT(pd.bus != -1,
  752                 ("did not find matching entry for link %#x in the $PIR table",
  753                             pci_link->pl_id));
  754                         if (bootverbose)
  755                                 device_printf(dev,
  756                             "Using %d.%d.INT%c to route link %#x to IRQ %d\n",
  757                                     pd.bus, pd.device, pd.pin + 'A',
  758                                     pci_link->pl_id, pci_link->pl_irq);
  759                         error = pci_pir_biosroute(pd.bus, pd.device, 0, pd.pin,
  760                             pci_link->pl_irq);
  761                         if (error)
  762                                 device_printf(dev,
  763                             "ROUTE_INTERRUPT on resume for link %#x failed.\n",
  764                                     pci_link->pl_id);
  765                 }
  766         }
  767         return (0);
  768 }
  769 
  770 static device_method_t pir_methods[] = {
  771         /* Device interface */
  772         DEVMETHOD(device_probe,         pir_probe),
  773         DEVMETHOD(device_attach,        pir_attach),
  774         DEVMETHOD(device_resume,        pir_resume),
  775 
  776         { 0, 0 }
  777 };
  778 
  779 static driver_t pir_driver = {
  780         "pir",
  781         pir_methods,
  782         1,
  783 };
  784 
  785 static devclass_t pir_devclass;
  786 
  787 DRIVER_MODULE(pir, legacy, pir_driver, pir_devclass, 0, 0);

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