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/11.2/sys/i386/pci/pci_pir.c 331722 2018-03-29 02:50:57Z eadler $");
   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 uint8_t  pci_pir_search_irq(int bus, int device, int pin);
   96 static int      pci_pir_valid_irq(struct pci_link *pci_link, int irq);
   97 static void     pci_pir_walk_table(pir_entry_handler *handler, void *arg);
   98 
   99 static MALLOC_DEFINE(M_PIR, "$PIR", "$PIR structures");
  100 
  101 static struct PIR_table *pci_route_table;
  102 static device_t pir_device;
  103 static int pci_route_count, pir_bios_irqs, pir_parsed;
  104 static TAILQ_HEAD(, pci_link) pci_links;
  105 static int pir_interrupt_weight[NUM_ISA_INTERRUPTS];
  106 
  107 /* sysctl vars */
  108 SYSCTL_DECL(_hw_pci);
  109 
  110 /* XXX this likely should live in a header file */
  111 #ifdef PC98
  112 /* IRQs 3, 5, 7, 9, 10, 11, 12, 13 */
  113 #define PCI_IRQ_OVERRIDE_MASK 0x3e68
  114 #else
  115 /* IRQs 3, 4, 5, 6, 7, 9, 10, 11, 12, 14, 15 */
  116 #define PCI_IRQ_OVERRIDE_MASK 0xdef8
  117 #endif
  118 
  119 static uint32_t pci_irq_override_mask = PCI_IRQ_OVERRIDE_MASK;
  120 SYSCTL_INT(_hw_pci, OID_AUTO, irq_override_mask, CTLFLAG_RDTUN,
  121     &pci_irq_override_mask, PCI_IRQ_OVERRIDE_MASK,
  122     "Mask of allowed irqs to try to route when it has no good clue about\n"
  123     "which irqs it should use.");
  124 
  125 /*
  126  * Look for the interrupt routing table.
  127  *
  128  * We use PCI BIOS's PIR table if it's available. $PIR is the standard way
  129  * to do this.  Sadly, some machines are not standards conforming and have
  130  * _PIR instead.  We shrug and cope by looking for both.
  131  */
  132 void
  133 pci_pir_open(void)
  134 {
  135         struct PIR_table *pt;
  136         uint32_t sigaddr;
  137         int i;
  138         uint8_t ck, *cv;
  139 
  140         /* Don't try if we've already found a table. */
  141         if (pci_route_table != NULL)
  142                 return;
  143 
  144         /* Look for $PIR and then _PIR. */
  145         sigaddr = bios_sigsearch(0, "$PIR", 4, 16, 0);
  146         if (sigaddr == 0)
  147                 sigaddr = bios_sigsearch(0, "_PIR", 4, 16, 0);
  148         if (sigaddr == 0)
  149                 return;
  150 
  151         /* If we found something, check the checksum and length. */
  152         /* XXX - Use pmap_mapdev()? */
  153         pt = (struct PIR_table *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
  154         if (pt->pt_header.ph_length <= sizeof(struct PIR_header))
  155                 return;
  156         for (cv = (u_int8_t *)pt, ck = 0, i = 0;
  157              i < (pt->pt_header.ph_length); i++)
  158                 ck += cv[i];
  159         if (ck != 0)
  160                 return;
  161 
  162         /* Ok, we've got a valid table. */
  163         pci_route_table = pt;
  164         pci_route_count = (pt->pt_header.ph_length -
  165             sizeof(struct PIR_header)) / 
  166             sizeof(struct PIR_entry);
  167 }
  168 
  169 /*
  170  * Find the pci_link structure for a given link ID.
  171  */
  172 static struct pci_link *
  173 pci_pir_find_link(uint8_t link_id)
  174 {
  175         struct pci_link *pci_link;
  176 
  177         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  178                 if (pci_link->pl_id == link_id)
  179                         return (pci_link);
  180         }
  181         return (NULL);
  182 }
  183 
  184 /*
  185  * Find the link device associated with a PCI device in the table.
  186  */
  187 static void
  188 pci_pir_find_link_handler(struct PIR_entry *entry, struct PIR_intpin *intpin,
  189     void *arg)
  190 {
  191         struct pci_link_lookup *lookup;
  192 
  193         lookup = (struct pci_link_lookup *)arg;
  194         if (entry->pe_bus == lookup->bus &&
  195             entry->pe_device == lookup->device &&
  196             intpin - entry->pe_intpin == lookup->pin)
  197                 *lookup->pci_link_ptr = pci_pir_find_link(intpin->link);
  198 }
  199 
  200 /*
  201  * Check to see if a possible IRQ setting is valid.
  202  */
  203 static int
  204 pci_pir_valid_irq(struct pci_link *pci_link, int irq)
  205 {
  206 
  207         if (!PCI_INTERRUPT_VALID(irq))
  208                 return (0);
  209         return (pci_link->pl_irqmask & (1 << irq));
  210 }
  211 
  212 /*
  213  * Walk the $PIR executing the worker function for each valid intpin entry
  214  * in the table.  The handler is passed a pointer to both the entry and
  215  * the intpin in the entry.
  216  */
  217 static void
  218 pci_pir_walk_table(pir_entry_handler *handler, void *arg)
  219 {
  220         struct PIR_entry *entry;
  221         struct PIR_intpin *intpin;
  222         int i, pin;
  223 
  224         entry = &pci_route_table->pt_entry[0];
  225         for (i = 0; i < pci_route_count; i++, entry++) {
  226                 intpin = &entry->pe_intpin[0];
  227                 for (pin = 0; pin < 4; pin++, intpin++)
  228                         if (intpin->link != 0)
  229                                 handler(entry, intpin, arg);
  230         }
  231 }
  232 
  233 static void
  234 pci_pir_create_links(struct PIR_entry *entry, struct PIR_intpin *intpin,
  235     void *arg)
  236 {
  237         struct pci_link *pci_link;
  238 
  239         pci_link = pci_pir_find_link(intpin->link);
  240         if (pci_link != NULL) {
  241                 pci_link->pl_references++;
  242                 if (intpin->irqs != pci_link->pl_irqmask) {
  243                         if (bootverbose)
  244                                 printf(
  245         "$PIR: Entry %d.%d.INT%c has different mask for link %#x, merging\n",
  246                                     entry->pe_bus, entry->pe_device,
  247                                     (intpin - entry->pe_intpin) + 'A',
  248                                     pci_link->pl_id);
  249                         pci_link->pl_irqmask &= intpin->irqs;
  250                 }
  251         } else {
  252                 pci_link = malloc(sizeof(struct pci_link), M_PIR, M_WAITOK);
  253                 pci_link->pl_id = intpin->link;
  254                 pci_link->pl_irqmask = intpin->irqs;
  255                 pci_link->pl_irq = PCI_INVALID_IRQ;
  256                 pci_link->pl_references = 1;
  257                 pci_link->pl_routed = 0;
  258                 TAILQ_INSERT_TAIL(&pci_links, pci_link, pl_links);
  259         }
  260 }
  261 
  262 /*
  263  * Look to see if any of the function on the PCI device at bus/device have
  264  * an interrupt routed to intpin 'pin' by the BIOS.
  265  */
  266 static uint8_t
  267 pci_pir_search_irq(int bus, int device, int pin)
  268 {
  269         uint32_t value;
  270         uint8_t func, maxfunc;
  271 
  272         /* See if we have a valid device at function 0. */
  273         value = pci_cfgregread(bus, device, 0, PCIR_HDRTYPE, 1);
  274         if ((value & PCIM_HDRTYPE) > PCI_MAXHDRTYPE)
  275                 return (PCI_INVALID_IRQ);
  276         if (value & PCIM_MFDEV)
  277                 maxfunc = PCI_FUNCMAX;
  278         else
  279                 maxfunc = 0;
  280 
  281         /* Scan all possible functions at this device. */
  282         for (func = 0; func <= maxfunc; func++) {
  283                 value = pci_cfgregread(bus, device, func, PCIR_DEVVENDOR, 4);
  284                 if (value == 0xffffffff)
  285                         continue;
  286                 value = pci_cfgregread(bus, device, func, PCIR_INTPIN, 1);
  287 
  288                 /*
  289                  * See if it uses the pin in question.  Note that the passed
  290                  * in pin uses 0 for A, .. 3 for D whereas the intpin
  291                  * register uses 0 for no interrupt, 1 for A, .. 4 for D.
  292                  */
  293                 if (value != pin + 1)
  294                         continue;
  295                 value = pci_cfgregread(bus, device, func, PCIR_INTLINE, 1);
  296                 if (bootverbose)
  297                         printf(
  298                 "$PIR: Found matching pin for %d.%d.INT%c at func %d: %d\n",
  299                             bus, device, pin + 'A', func, value);
  300                 if (value != PCI_INVALID_IRQ)
  301                         return (value);
  302         }
  303         return (PCI_INVALID_IRQ);
  304 }
  305 
  306 /*
  307  * Try to initialize IRQ based on this device's IRQ.
  308  */
  309 static void
  310 pci_pir_initial_irqs(struct PIR_entry *entry, struct PIR_intpin *intpin,
  311     void *arg)
  312 {
  313         struct pci_link *pci_link;
  314         uint8_t irq, pin;
  315 
  316         pin = intpin - entry->pe_intpin;
  317         pci_link = pci_pir_find_link(intpin->link);
  318         irq = pci_pir_search_irq(entry->pe_bus, entry->pe_device, pin);
  319         if (irq == PCI_INVALID_IRQ || irq == pci_link->pl_irq)
  320                 return;
  321 
  322         /* Don't trust any BIOS IRQs greater than 15. */
  323         if (irq >= NUM_ISA_INTERRUPTS) {
  324                 printf(
  325         "$PIR: Ignoring invalid BIOS IRQ %d from %d.%d.INT%c for link %#x\n",
  326                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  327                     pci_link->pl_id);
  328                 return;
  329         }
  330 
  331         /*
  332          * If we don't have an IRQ for this link yet, then we trust the
  333          * BIOS, even if it seems invalid from the $PIR entries.
  334          */
  335         if (pci_link->pl_irq == PCI_INVALID_IRQ) {
  336                 if (!pci_pir_valid_irq(pci_link, irq))
  337                         printf(
  338         "$PIR: Using invalid BIOS IRQ %d from %d.%d.INT%c for link %#x\n",
  339                             irq, entry->pe_bus, entry->pe_device, pin + 'A',
  340                             pci_link->pl_id);
  341                 pci_link->pl_irq = irq;
  342                 pci_link->pl_routed = 1;
  343                 return;
  344         }
  345 
  346         /*
  347          * We have an IRQ and it doesn't match the current IRQ for this
  348          * link.  If the new IRQ is invalid, then warn about it and ignore
  349          * it.  If the old IRQ is invalid and the new IRQ is valid, then
  350          * prefer the new IRQ instead.  If both IRQs are valid, then just
  351          * use the first one.  Note that if we ever get into this situation
  352          * we are having to guess which setting the BIOS actually routed.
  353          * Perhaps we should just give up instead.
  354          */
  355         if (!pci_pir_valid_irq(pci_link, irq)) {
  356                 printf(
  357                 "$PIR: BIOS IRQ %d for %d.%d.INT%c is not valid for link %#x\n",
  358                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  359                     pci_link->pl_id);
  360         } else if (!pci_pir_valid_irq(pci_link, pci_link->pl_irq)) {
  361                 printf(
  362 "$PIR: Preferring valid BIOS IRQ %d from %d.%d.INT%c for link %#x to IRQ %d\n", 
  363                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  364                     pci_link->pl_id, pci_link->pl_irq);
  365                 pci_link->pl_irq = irq;
  366                 pci_link->pl_routed = 1;
  367         } else
  368                 printf(
  369         "$PIR: BIOS IRQ %d for %d.%d.INT%c does not match link %#x irq %d\n",
  370                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  371                     pci_link->pl_id, pci_link->pl_irq);
  372 }
  373 
  374 /*
  375  * Parse $PIR to enumerate link devices and attempt to determine their
  376  * initial state.  This could perhaps be cleaner if we had drivers for the
  377  * various interrupt routers as they could read the initial IRQ for each
  378  * link.
  379  */
  380 static void
  381 pci_pir_parse(void)
  382 {
  383         char tunable_buffer[64];
  384         struct pci_link *pci_link;
  385         int i, irq;
  386 
  387         /* Only parse once. */
  388         if (pir_parsed)
  389                 return;
  390         pir_parsed = 1;
  391 
  392         /* Enumerate link devices. */
  393         TAILQ_INIT(&pci_links);
  394         pci_pir_walk_table(pci_pir_create_links, NULL);
  395         if (bootverbose) {
  396                 printf("$PIR: Links after initial probe:\n");
  397                 pci_pir_dump_links();
  398         }
  399 
  400         /*
  401          * Check to see if the BIOS has already routed any of the links by
  402          * checking each device connected to each link to see if it has a
  403          * valid IRQ.
  404          */
  405         pci_pir_walk_table(pci_pir_initial_irqs, NULL);
  406         if (bootverbose) {
  407                 printf("$PIR: Links after initial IRQ discovery:\n");
  408                 pci_pir_dump_links();
  409         }
  410 
  411         /*
  412          * Allow the user to override the IRQ for a given link device.  We
  413          * allow invalid IRQs to be specified but warn about them.  An IRQ
  414          * of 255 or 0 clears any preset IRQ.
  415          */
  416         i = 0;
  417         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  418                 snprintf(tunable_buffer, sizeof(tunable_buffer),
  419                     "hw.pci.link.%#x.irq", pci_link->pl_id);
  420                 if (getenv_int(tunable_buffer, &irq) == 0)
  421                         continue;
  422                 if (irq == 0)
  423                         irq = PCI_INVALID_IRQ;
  424                 if (irq != PCI_INVALID_IRQ &&
  425                     !pci_pir_valid_irq(pci_link, irq) && bootverbose)
  426                         printf(
  427                 "$PIR: Warning, IRQ %d for link %#x is not listed as valid\n",
  428                             irq, pci_link->pl_id);
  429                 pci_link->pl_routed = 0;
  430                 pci_link->pl_irq = irq;
  431                 i = 1;
  432         }
  433         if (bootverbose && i) {
  434                 printf("$PIR: Links after tunable overrides:\n");
  435                 pci_pir_dump_links();
  436         }
  437 
  438         /*
  439          * Build initial interrupt weights as well as bitmap of "known-good"
  440          * IRQs that the BIOS has already used for PCI link devices.
  441          */
  442         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  443                 if (!PCI_INTERRUPT_VALID(pci_link->pl_irq))
  444                         continue;
  445                 pir_bios_irqs |= 1 << pci_link->pl_irq;
  446                 pir_interrupt_weight[pci_link->pl_irq] +=
  447                     pci_link->pl_references;
  448         }
  449         if (bootverbose) {
  450                 printf("$PIR: IRQs used by BIOS: ");
  451                 pci_print_irqmask(pir_bios_irqs);
  452                 printf("\n");
  453                 printf("$PIR: Interrupt Weights:\n[ ");
  454                 for (i = 0; i < NUM_ISA_INTERRUPTS; i++)
  455                         printf(" %3d", i);
  456                 printf(" ]\n[ ");
  457                 for (i = 0; i < NUM_ISA_INTERRUPTS; i++)
  458                         printf(" %3d", pir_interrupt_weight[i]);
  459                 printf(" ]\n");
  460         }
  461 }
  462 
  463 /*
  464  * Use the PCI BIOS to route an interrupt for a given device.
  465  *
  466  * Input:
  467  * AX = PCIBIOS_ROUTE_INTERRUPT
  468  * BH = bus
  469  * BL = device [7:3] / function [2:0]
  470  * CH = IRQ
  471  * CL = Interrupt Pin (0x0A = A, ... 0x0D = D)
  472  */
  473 static int
  474 pci_pir_biosroute(int bus, int device, int func, int pin, int irq)
  475 {
  476         struct bios_regs args;
  477 
  478         args.eax = PCIBIOS_ROUTE_INTERRUPT;
  479         args.ebx = (bus << 8) | (device << 3) | func;
  480         args.ecx = (irq << 8) | (0xa + pin);
  481         return (bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL)));
  482 }
  483 
  484 
  485 /*
  486  * Route a PCI interrupt using a link device from the $PIR.
  487  */
  488 int
  489 pci_pir_route_interrupt(int bus, int device, int func, int pin)
  490 {
  491         struct pci_link_lookup lookup;
  492         struct pci_link *pci_link;
  493         int error, irq;
  494 
  495         if (pci_route_table == NULL)
  496                 return (PCI_INVALID_IRQ);
  497 
  498         /* Lookup link device for this PCI device/pin. */
  499         pci_link = NULL;
  500         lookup.bus = bus;
  501         lookup.device = device;
  502         lookup.pin = pin - 1;
  503         lookup.pci_link_ptr = &pci_link;
  504         pci_pir_walk_table(pci_pir_find_link_handler, &lookup);
  505         if (pci_link == NULL) {
  506                 printf("$PIR: No matching entry for %d.%d.INT%c\n", bus,
  507                     device, pin - 1 + 'A');
  508                 return (PCI_INVALID_IRQ);
  509         }
  510 
  511         /*
  512          * Pick a new interrupt if we don't have one already.  We look
  513          * for an interrupt from several different sets.  First, if
  514          * this link only has one valid IRQ, use that.  Second, we
  515          * check the set of PCI only interrupts from the $PIR.  Third,
  516          * we check the set of known-good interrupts that the BIOS has
  517          * already used.  Lastly, we check the "all possible valid
  518          * IRQs" set.
  519          */
  520         if (!PCI_INTERRUPT_VALID(pci_link->pl_irq)) {
  521                 if (pci_link->pl_irqmask != 0 && powerof2(pci_link->pl_irqmask))
  522                         irq = ffs(pci_link->pl_irqmask) - 1;
  523                 else
  524                         irq = pci_pir_choose_irq(pci_link,
  525                             pci_route_table->pt_header.ph_pci_irqs);
  526                 if (!PCI_INTERRUPT_VALID(irq))
  527                         irq = pci_pir_choose_irq(pci_link, pir_bios_irqs);
  528                 if (!PCI_INTERRUPT_VALID(irq))
  529                         irq = pci_pir_choose_irq(pci_link,
  530                             pci_irq_override_mask);
  531                 if (!PCI_INTERRUPT_VALID(irq)) {
  532                         if (bootverbose)
  533                                 printf(
  534                         "$PIR: Failed to route interrupt for %d:%d INT%c\n",
  535                                     bus, device, pin - 1 + 'A');
  536                         return (PCI_INVALID_IRQ);
  537                 }
  538                 pci_link->pl_irq = irq;
  539         }
  540 
  541         /* Ask the BIOS to route this IRQ if we haven't done so already. */
  542         if (!pci_link->pl_routed) {
  543                 error = pci_pir_biosroute(bus, device, func, pin - 1,
  544                     pci_link->pl_irq);
  545 
  546                 /* Ignore errors when routing a unique interrupt. */
  547                 if (error && !powerof2(pci_link->pl_irqmask)) {
  548                         printf("$PIR: ROUTE_INTERRUPT failed.\n");
  549                         return (PCI_INVALID_IRQ);
  550                 }
  551                 pci_link->pl_routed = 1;
  552 
  553                 /* Ensure the interrupt is set to level/low trigger. */
  554                 KASSERT(pir_device != NULL, ("missing pir device"));
  555                 BUS_CONFIG_INTR(pir_device, pci_link->pl_irq,
  556                     INTR_TRIGGER_LEVEL, INTR_POLARITY_LOW);
  557         }
  558         if (bootverbose)
  559                 printf("$PIR: %d:%d INT%c routed to irq %d\n", bus, device,
  560                     pin - 1 + 'A', pci_link->pl_irq);
  561         return (pci_link->pl_irq);
  562 }
  563 
  564 /*
  565  * Try to pick an interrupt for the specified link from the interrupts
  566  * set in the mask.
  567  */
  568 static int
  569 pci_pir_choose_irq(struct pci_link *pci_link, int irqmask)
  570 {
  571         int i, irq, realmask;
  572 
  573         /* XXX: Need to have a #define of known bad IRQs to also mask out? */
  574         realmask = pci_link->pl_irqmask & irqmask;
  575         if (realmask == 0)
  576                 return (PCI_INVALID_IRQ);
  577 
  578         /* Find IRQ with lowest weight. */
  579         irq = PCI_INVALID_IRQ;
  580         for (i = 0; i < NUM_ISA_INTERRUPTS; i++) {
  581                 if (!(realmask & 1 << i))
  582                         continue;
  583                 if (irq == PCI_INVALID_IRQ ||
  584                     pir_interrupt_weight[i] < pir_interrupt_weight[irq])
  585                         irq = i;
  586         }
  587         if (bootverbose && PCI_INTERRUPT_VALID(irq)) {
  588                 printf("$PIR: Found IRQ %d for link %#x from ", irq,
  589                     pci_link->pl_id);
  590                 pci_print_irqmask(realmask);
  591                 printf("\n");
  592         }
  593         return (irq);
  594 }
  595 
  596 static void
  597 pci_print_irqmask(u_int16_t irqs)
  598 {
  599         int i, first;
  600 
  601         if (irqs == 0) {
  602                 printf("none");
  603                 return;
  604         }
  605         first = 1;
  606         for (i = 0; i < 16; i++, irqs >>= 1)
  607                 if (irqs & 1) {
  608                         if (!first)
  609                                 printf(" ");
  610                         else
  611                                 first = 0;
  612                         printf("%d", i);
  613                 }
  614 }
  615 
  616 /*
  617  * Display link devices.
  618  */
  619 static void
  620 pci_pir_dump_links(void)
  621 {
  622         struct pci_link *pci_link;
  623 
  624         printf("Link  IRQ  Rtd  Ref  IRQs\n");
  625         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  626                 printf("%#4x  %3d   %c   %3d  ", pci_link->pl_id,
  627                     pci_link->pl_irq, pci_link->pl_routed ? 'Y' : 'N',
  628                     pci_link->pl_references);
  629                 pci_print_irqmask(pci_link->pl_irqmask);
  630                 printf("\n");
  631         }
  632 }
  633 
  634 /*
  635  * See if any interrupts for a given PCI bus are routed in the PIR.  Don't
  636  * even bother looking if the BIOS doesn't support routing anyways.  If we
  637  * are probing a PCI-PCI bridge, then require_parse will be true and we should
  638  * only succeed if a host-PCI bridge has already attached and parsed the PIR.
  639  */
  640 int
  641 pci_pir_probe(int bus, int require_parse)
  642 {
  643         int i;
  644 
  645         if (pci_route_table == NULL || (require_parse && !pir_parsed))
  646                 return (0);
  647         for (i = 0; i < pci_route_count; i++)
  648                 if (pci_route_table->pt_entry[i].pe_bus == bus)
  649                         return (1);
  650         return (0);
  651 }
  652 
  653 /*
  654  * The driver for the new-bus psuedo device pir0 for the $PIR table.
  655  */
  656 
  657 static int
  658 pir_probe(device_t dev)
  659 {
  660         char buf[64];
  661 
  662         snprintf(buf, sizeof(buf), "PCI Interrupt Routing Table: %d Entries",
  663             pci_route_count);
  664         device_set_desc_copy(dev, buf);
  665         return (0);
  666 }
  667 
  668 static int
  669 pir_attach(device_t dev)
  670 {
  671 
  672         pci_pir_parse();
  673         KASSERT(pir_device == NULL, ("Multiple pir devices"));
  674         pir_device = dev;
  675         return (0);
  676 }
  677 
  678 static void
  679 pir_resume_find_device(struct PIR_entry *entry, struct PIR_intpin *intpin,
  680     void *arg)
  681 {
  682         struct pci_dev_lookup *pd;
  683 
  684         pd = (struct pci_dev_lookup *)arg;
  685         if (intpin->link != pd->link || pd->bus != -1)
  686                 return;
  687         pd->bus = entry->pe_bus;
  688         pd->device = entry->pe_device;
  689         pd->pin = intpin - entry->pe_intpin;
  690 }
  691 
  692 static int
  693 pir_resume(device_t dev)
  694 {
  695         struct pci_dev_lookup pd;
  696         struct pci_link *pci_link;
  697         int error;
  698 
  699         /* Ask the BIOS to re-route each link that was already routed. */
  700         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  701                 if (!PCI_INTERRUPT_VALID(pci_link->pl_irq)) {
  702                         KASSERT(!pci_link->pl_routed,
  703                             ("link %#x is routed but has invalid PCI IRQ",
  704                             pci_link->pl_id));
  705                         continue;
  706                 }
  707                 if (pci_link->pl_routed) {
  708                         pd.bus = -1;
  709                         pd.link = pci_link->pl_id;
  710                         pci_pir_walk_table(pir_resume_find_device, &pd);
  711                         KASSERT(pd.bus != -1,
  712                 ("did not find matching entry for link %#x in the $PIR table",
  713                             pci_link->pl_id));
  714                         if (bootverbose)
  715                                 device_printf(dev,
  716                             "Using %d.%d.INT%c to route link %#x to IRQ %d\n",
  717                                     pd.bus, pd.device, pd.pin + 'A',
  718                                     pci_link->pl_id, pci_link->pl_irq);
  719                         error = pci_pir_biosroute(pd.bus, pd.device, 0, pd.pin,
  720                             pci_link->pl_irq);
  721                         if (error)
  722                                 device_printf(dev,
  723                             "ROUTE_INTERRUPT on resume for link %#x failed.\n",
  724                                     pci_link->pl_id);
  725                 }
  726         }
  727         return (0);
  728 }
  729 
  730 static device_method_t pir_methods[] = {
  731         /* Device interface */
  732         DEVMETHOD(device_probe,         pir_probe),
  733         DEVMETHOD(device_attach,        pir_attach),
  734         DEVMETHOD(device_resume,        pir_resume),
  735 
  736         { 0, 0 }
  737 };
  738 
  739 static driver_t pir_driver = {
  740         "pir",
  741         pir_methods,
  742         1,
  743 };
  744 
  745 static devclass_t pir_devclass;
  746 
  747 DRIVER_MODULE(pir, legacy, pir_driver, pir_devclass, 0, 0);

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