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/9.2/sys/i386/pci/pci_pir.c 181775 2008-08-15 20:51:31Z kmacy $");
   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 TUNABLE_INT("hw.pci.irq_override_mask", &pci_irq_override_mask);
  121 SYSCTL_INT(_hw_pci, OID_AUTO, irq_override_mask, CTLFLAG_RDTUN,
  122     &pci_irq_override_mask, PCI_IRQ_OVERRIDE_MASK,
  123     "Mask of allowed irqs to try to route when it has no good clue about\n"
  124     "which irqs it should use.");
  125 
  126 /*
  127  * Look for the interrupt routing table.
  128  *
  129  * We use PCI BIOS's PIR table if it's available. $PIR is the standard way
  130  * to do this.  Sadly, some machines are not standards conforming and have
  131  * _PIR instead.  We shrug and cope by looking for both.
  132  */
  133 void
  134 pci_pir_open(void)
  135 {
  136         struct PIR_table *pt;
  137         uint32_t sigaddr;
  138         int i;
  139         uint8_t ck, *cv;
  140 
  141 #ifdef XEN
  142         return;
  143 #else   
  144         /* Don't try if we've already found a table. */
  145         if (pci_route_table != NULL)
  146                 return;
  147 
  148         /* Look for $PIR and then _PIR. */
  149         sigaddr = bios_sigsearch(0, "$PIR", 4, 16, 0);
  150         if (sigaddr == 0)
  151                 sigaddr = bios_sigsearch(0, "_PIR", 4, 16, 0);
  152         if (sigaddr == 0)
  153                 return;
  154 #endif
  155         /* If we found something, check the checksum and length. */
  156         /* XXX - Use pmap_mapdev()? */
  157         pt = (struct PIR_table *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
  158         if (pt->pt_header.ph_length <= sizeof(struct PIR_header))
  159                 return;
  160         for (cv = (u_int8_t *)pt, ck = 0, i = 0;
  161              i < (pt->pt_header.ph_length); i++)
  162                 ck += cv[i];
  163         if (ck != 0)
  164                 return;
  165 
  166         /* Ok, we've got a valid table. */
  167         pci_route_table = pt;
  168         pci_route_count = (pt->pt_header.ph_length -
  169             sizeof(struct PIR_header)) / 
  170             sizeof(struct PIR_entry);
  171 }
  172 
  173 /*
  174  * Find the pci_link structure for a given link ID.
  175  */
  176 static struct pci_link *
  177 pci_pir_find_link(uint8_t link_id)
  178 {
  179         struct pci_link *pci_link;
  180 
  181         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  182                 if (pci_link->pl_id == link_id)
  183                         return (pci_link);
  184         }
  185         return (NULL);
  186 }
  187 
  188 /*
  189  * Find the link device associated with a PCI device in the table.
  190  */
  191 static void
  192 pci_pir_find_link_handler(struct PIR_entry *entry, struct PIR_intpin *intpin,
  193     void *arg)
  194 {
  195         struct pci_link_lookup *lookup;
  196 
  197         lookup = (struct pci_link_lookup *)arg;
  198         if (entry->pe_bus == lookup->bus &&
  199             entry->pe_device == lookup->device &&
  200             intpin - entry->pe_intpin == lookup->pin)
  201                 *lookup->pci_link_ptr = pci_pir_find_link(intpin->link);
  202 }
  203 
  204 /*
  205  * Check to see if a possible IRQ setting is valid.
  206  */
  207 static int
  208 pci_pir_valid_irq(struct pci_link *pci_link, int irq)
  209 {
  210 
  211         if (!PCI_INTERRUPT_VALID(irq))
  212                 return (0);
  213         return (pci_link->pl_irqmask & (1 << irq));
  214 }
  215 
  216 /*
  217  * Walk the $PIR executing the worker function for each valid intpin entry
  218  * in the table.  The handler is passed a pointer to both the entry and
  219  * the intpin in the entry.
  220  */
  221 static void
  222 pci_pir_walk_table(pir_entry_handler *handler, void *arg)
  223 {
  224         struct PIR_entry *entry;
  225         struct PIR_intpin *intpin;
  226         int i, pin;
  227 
  228         entry = &pci_route_table->pt_entry[0];
  229         for (i = 0; i < pci_route_count; i++, entry++) {
  230                 intpin = &entry->pe_intpin[0];
  231                 for (pin = 0; pin < 4; pin++, intpin++)
  232                         if (intpin->link != 0)
  233                                 handler(entry, intpin, arg);
  234         }
  235 }
  236 
  237 static void
  238 pci_pir_create_links(struct PIR_entry *entry, struct PIR_intpin *intpin,
  239     void *arg)
  240 {
  241         struct pci_link *pci_link;
  242 
  243         pci_link = pci_pir_find_link(intpin->link);
  244         if (pci_link != NULL) {
  245                 pci_link->pl_references++;
  246                 if (intpin->irqs != pci_link->pl_irqmask) {
  247                         if (bootverbose)
  248                                 printf(
  249         "$PIR: Entry %d.%d.INT%c has different mask for link %#x, merging\n",
  250                                     entry->pe_bus, entry->pe_device,
  251                                     (intpin - entry->pe_intpin) + 'A',
  252                                     pci_link->pl_id);
  253                         pci_link->pl_irqmask &= intpin->irqs;
  254                 }
  255         } else {
  256                 pci_link = malloc(sizeof(struct pci_link), M_PIR, M_WAITOK);
  257                 pci_link->pl_id = intpin->link;
  258                 pci_link->pl_irqmask = intpin->irqs;
  259                 pci_link->pl_irq = PCI_INVALID_IRQ;
  260                 pci_link->pl_references = 1;
  261                 pci_link->pl_routed = 0;
  262                 TAILQ_INSERT_TAIL(&pci_links, pci_link, pl_links);
  263         }
  264 }
  265 
  266 /*
  267  * Look to see if any of the function on the PCI device at bus/device have
  268  * an interrupt routed to intpin 'pin' by the BIOS.
  269  */
  270 static uint8_t
  271 pci_pir_search_irq(int bus, int device, int pin)
  272 {
  273         uint32_t value;
  274         uint8_t func, maxfunc;
  275 
  276         /* See if we have a valid device at function 0. */
  277         value = pci_cfgregread(bus, device, 0, PCIR_HDRTYPE, 1);
  278         if ((value & PCIM_HDRTYPE) > PCI_MAXHDRTYPE)
  279                 return (PCI_INVALID_IRQ);
  280         if (value & PCIM_MFDEV)
  281                 maxfunc = PCI_FUNCMAX;
  282         else
  283                 maxfunc = 0;
  284 
  285         /* Scan all possible functions at this device. */
  286         for (func = 0; func <= maxfunc; func++) {
  287                 value = pci_cfgregread(bus, device, func, PCIR_DEVVENDOR, 4);
  288                 if (value == 0xffffffff)
  289                         continue;
  290                 value = pci_cfgregread(bus, device, func, PCIR_INTPIN, 1);
  291 
  292                 /*
  293                  * See if it uses the pin in question.  Note that the passed
  294                  * in pin uses 0 for A, .. 3 for D whereas the intpin
  295                  * register uses 0 for no interrupt, 1 for A, .. 4 for D.
  296                  */
  297                 if (value != pin + 1)
  298                         continue;
  299                 value = pci_cfgregread(bus, device, func, PCIR_INTLINE, 1);
  300                 if (bootverbose)
  301                         printf(
  302                 "$PIR: Found matching pin for %d.%d.INT%c at func %d: %d\n",
  303                             bus, device, pin + 'A', func, value);
  304                 if (value != PCI_INVALID_IRQ)
  305                         return (value);
  306         }
  307         return (PCI_INVALID_IRQ);
  308 }
  309 
  310 /*
  311  * Try to initialize IRQ based on this device's IRQ.
  312  */
  313 static void
  314 pci_pir_initial_irqs(struct PIR_entry *entry, struct PIR_intpin *intpin,
  315     void *arg)
  316 {
  317         struct pci_link *pci_link;
  318         uint8_t irq, pin;
  319 
  320         pin = intpin - entry->pe_intpin;
  321         pci_link = pci_pir_find_link(intpin->link);
  322         irq = pci_pir_search_irq(entry->pe_bus, entry->pe_device, pin);
  323         if (irq == PCI_INVALID_IRQ || irq == pci_link->pl_irq)
  324                 return;
  325 
  326         /* Don't trust any BIOS IRQs greater than 15. */
  327         if (irq >= NUM_ISA_INTERRUPTS) {
  328                 printf(
  329         "$PIR: Ignoring invalid BIOS IRQ %d from %d.%d.INT%c for link %#x\n",
  330                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  331                     pci_link->pl_id);
  332                 return;
  333         }
  334 
  335         /*
  336          * If we don't have an IRQ for this link yet, then we trust the
  337          * BIOS, even if it seems invalid from the $PIR entries.
  338          */
  339         if (pci_link->pl_irq == PCI_INVALID_IRQ) {
  340                 if (!pci_pir_valid_irq(pci_link, irq))
  341                         printf(
  342         "$PIR: Using invalid BIOS IRQ %d from %d.%d.INT%c for link %#x\n",
  343                             irq, entry->pe_bus, entry->pe_device, pin + 'A',
  344                             pci_link->pl_id);
  345                 pci_link->pl_irq = irq;
  346                 pci_link->pl_routed = 1;
  347                 return;
  348         }
  349 
  350         /*
  351          * We have an IRQ and it doesn't match the current IRQ for this
  352          * link.  If the new IRQ is invalid, then warn about it and ignore
  353          * it.  If the old IRQ is invalid and the new IRQ is valid, then
  354          * prefer the new IRQ instead.  If both IRQs are valid, then just
  355          * use the first one.  Note that if we ever get into this situation
  356          * we are having to guess which setting the BIOS actually routed.
  357          * Perhaps we should just give up instead.
  358          */
  359         if (!pci_pir_valid_irq(pci_link, irq)) {
  360                 printf(
  361                 "$PIR: BIOS IRQ %d for %d.%d.INT%c is not valid for link %#x\n",
  362                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  363                     pci_link->pl_id);
  364         } else if (!pci_pir_valid_irq(pci_link, pci_link->pl_irq)) {
  365                 printf(
  366 "$PIR: Preferring valid BIOS IRQ %d from %d.%d.INT%c for link %#x to IRQ %d\n", 
  367                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  368                     pci_link->pl_id, pci_link->pl_irq);
  369                 pci_link->pl_irq = irq;
  370                 pci_link->pl_routed = 1;
  371         } else
  372                 printf(
  373         "$PIR: BIOS IRQ %d for %d.%d.INT%c does not match link %#x irq %d\n",
  374                     irq, entry->pe_bus, entry->pe_device, pin + 'A',
  375                     pci_link->pl_id, pci_link->pl_irq);
  376 }
  377 
  378 /*
  379  * Parse $PIR to enumerate link devices and attempt to determine their
  380  * initial state.  This could perhaps be cleaner if we had drivers for the
  381  * various interrupt routers as they could read the initial IRQ for each
  382  * link.
  383  */
  384 static void
  385 pci_pir_parse(void)
  386 {
  387         char tunable_buffer[64];
  388         struct pci_link *pci_link;
  389         int i, irq;
  390 
  391         /* Only parse once. */
  392         if (pir_parsed)
  393                 return;
  394         pir_parsed = 1;
  395 
  396         /* Enumerate link devices. */
  397         TAILQ_INIT(&pci_links);
  398         pci_pir_walk_table(pci_pir_create_links, NULL);
  399         if (bootverbose) {
  400                 printf("$PIR: Links after initial probe:\n");
  401                 pci_pir_dump_links();
  402         }
  403 
  404         /*
  405          * Check to see if the BIOS has already routed any of the links by
  406          * checking each device connected to each link to see if it has a
  407          * valid IRQ.
  408          */
  409         pci_pir_walk_table(pci_pir_initial_irqs, NULL);
  410         if (bootverbose) {
  411                 printf("$PIR: Links after initial IRQ discovery:\n");
  412                 pci_pir_dump_links();
  413         }
  414 
  415         /*
  416          * Allow the user to override the IRQ for a given link device.  We
  417          * allow invalid IRQs to be specified but warn about them.  An IRQ
  418          * of 255 or 0 clears any preset IRQ.
  419          */
  420         i = 0;
  421         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  422                 snprintf(tunable_buffer, sizeof(tunable_buffer),
  423                     "hw.pci.link.%#x.irq", pci_link->pl_id);
  424                 if (getenv_int(tunable_buffer, &irq) == 0)
  425                         continue;
  426                 if (irq == 0)
  427                         irq = PCI_INVALID_IRQ;
  428                 if (irq != PCI_INVALID_IRQ &&
  429                     !pci_pir_valid_irq(pci_link, irq) && bootverbose)
  430                         printf(
  431                 "$PIR: Warning, IRQ %d for link %#x is not listed as valid\n",
  432                             irq, pci_link->pl_id);
  433                 pci_link->pl_routed = 0;
  434                 pci_link->pl_irq = irq;
  435                 i = 1;
  436         }
  437         if (bootverbose && i) {
  438                 printf("$PIR: Links after tunable overrides:\n");
  439                 pci_pir_dump_links();
  440         }
  441 
  442         /*
  443          * Build initial interrupt weights as well as bitmap of "known-good"
  444          * IRQs that the BIOS has already used for PCI link devices.
  445          */
  446         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  447                 if (!PCI_INTERRUPT_VALID(pci_link->pl_irq))
  448                         continue;
  449                 pir_bios_irqs |= 1 << pci_link->pl_irq;
  450                 pir_interrupt_weight[pci_link->pl_irq] +=
  451                     pci_link->pl_references;
  452         }
  453         if (bootverbose) {
  454                 printf("$PIR: IRQs used by BIOS: ");
  455                 pci_print_irqmask(pir_bios_irqs);
  456                 printf("\n");
  457                 printf("$PIR: Interrupt Weights:\n[ ");
  458                 for (i = 0; i < NUM_ISA_INTERRUPTS; i++)
  459                         printf(" %3d", i);
  460                 printf(" ]\n[ ");
  461                 for (i = 0; i < NUM_ISA_INTERRUPTS; i++)
  462                         printf(" %3d", pir_interrupt_weight[i]);
  463                 printf(" ]\n");
  464         }
  465 }
  466 
  467 /*
  468  * Use the PCI BIOS to route an interrupt for a given device.
  469  *
  470  * Input:
  471  * AX = PCIBIOS_ROUTE_INTERRUPT
  472  * BH = bus
  473  * BL = device [7:3] / function [2:0]
  474  * CH = IRQ
  475  * CL = Interrupt Pin (0x0A = A, ... 0x0D = D)
  476  */
  477 static int
  478 pci_pir_biosroute(int bus, int device, int func, int pin, int irq)
  479 {
  480         struct bios_regs args;
  481 
  482         args.eax = PCIBIOS_ROUTE_INTERRUPT;
  483         args.ebx = (bus << 8) | (device << 3) | func;
  484         args.ecx = (irq << 8) | (0xa + pin);
  485 #ifdef XEN
  486         return (0);
  487 #else   
  488         return (bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL)));
  489 #endif
  490 }
  491 
  492 
  493 /*
  494  * Route a PCI interrupt using a link device from the $PIR.
  495  */
  496 int
  497 pci_pir_route_interrupt(int bus, int device, int func, int pin)
  498 {
  499         struct pci_link_lookup lookup;
  500         struct pci_link *pci_link;
  501         int error, irq;
  502 
  503         if (pci_route_table == NULL)
  504                 return (PCI_INVALID_IRQ);
  505 
  506         /* Lookup link device for this PCI device/pin. */
  507         pci_link = NULL;
  508         lookup.bus = bus;
  509         lookup.device = device;
  510         lookup.pin = pin - 1;
  511         lookup.pci_link_ptr = &pci_link;
  512         pci_pir_walk_table(pci_pir_find_link_handler, &lookup);
  513         if (pci_link == NULL) {
  514                 printf("$PIR: No matching entry for %d.%d.INT%c\n", bus,
  515                     device, pin - 1 + 'A');
  516                 return (PCI_INVALID_IRQ);
  517         }
  518 
  519         /*
  520          * Pick a new interrupt if we don't have one already.  We look
  521          * for an interrupt from several different sets.  First, if
  522          * this link only has one valid IRQ, use that.  Second, we
  523          * check the set of PCI only interrupts from the $PIR.  Third,
  524          * we check the set of known-good interrupts that the BIOS has
  525          * already used.  Lastly, we check the "all possible valid
  526          * IRQs" set.
  527          */
  528         if (!PCI_INTERRUPT_VALID(pci_link->pl_irq)) {
  529                 if (pci_link->pl_irqmask != 0 && powerof2(pci_link->pl_irqmask))
  530                         irq = ffs(pci_link->pl_irqmask) - 1;
  531                 else
  532                         irq = pci_pir_choose_irq(pci_link,
  533                             pci_route_table->pt_header.ph_pci_irqs);
  534                 if (!PCI_INTERRUPT_VALID(irq))
  535                         irq = pci_pir_choose_irq(pci_link, pir_bios_irqs);
  536                 if (!PCI_INTERRUPT_VALID(irq))
  537                         irq = pci_pir_choose_irq(pci_link,
  538                             pci_irq_override_mask);
  539                 if (!PCI_INTERRUPT_VALID(irq)) {
  540                         if (bootverbose)
  541                                 printf(
  542                         "$PIR: Failed to route interrupt for %d:%d INT%c\n",
  543                                     bus, device, pin - 1 + 'A');
  544                         return (PCI_INVALID_IRQ);
  545                 }
  546                 pci_link->pl_irq = irq;
  547         }
  548 
  549         /* Ask the BIOS to route this IRQ if we haven't done so already. */
  550         if (!pci_link->pl_routed) {
  551                 error = pci_pir_biosroute(bus, device, func, pin - 1,
  552                     pci_link->pl_irq);
  553 
  554                 /* Ignore errors when routing a unique interrupt. */
  555                 if (error && !powerof2(pci_link->pl_irqmask)) {
  556                         printf("$PIR: ROUTE_INTERRUPT failed.\n");
  557                         return (PCI_INVALID_IRQ);
  558                 }
  559                 pci_link->pl_routed = 1;
  560 
  561                 /* Ensure the interrupt is set to level/low trigger. */
  562                 KASSERT(pir_device != NULL, ("missing pir device"));
  563                 BUS_CONFIG_INTR(pir_device, pci_link->pl_irq,
  564                     INTR_TRIGGER_LEVEL, INTR_POLARITY_LOW);
  565         }
  566         if (bootverbose)
  567                 printf("$PIR: %d:%d INT%c routed to irq %d\n", bus, device,
  568                     pin - 1 + 'A', pci_link->pl_irq);
  569         return (pci_link->pl_irq);
  570 }
  571 
  572 /*
  573  * Try to pick an interrupt for the specified link from the interrupts
  574  * set in the mask.
  575  */
  576 static int
  577 pci_pir_choose_irq(struct pci_link *pci_link, int irqmask)
  578 {
  579         int i, irq, realmask;
  580 
  581         /* XXX: Need to have a #define of known bad IRQs to also mask out? */
  582         realmask = pci_link->pl_irqmask & irqmask;
  583         if (realmask == 0)
  584                 return (PCI_INVALID_IRQ);
  585 
  586         /* Find IRQ with lowest weight. */
  587         irq = PCI_INVALID_IRQ;
  588         for (i = 0; i < NUM_ISA_INTERRUPTS; i++) {
  589                 if (!(realmask & 1 << i))
  590                         continue;
  591                 if (irq == PCI_INVALID_IRQ ||
  592                     pir_interrupt_weight[i] < pir_interrupt_weight[irq])
  593                         irq = i;
  594         }
  595         if (bootverbose && PCI_INTERRUPT_VALID(irq)) {
  596                 printf("$PIR: Found IRQ %d for link %#x from ", irq,
  597                     pci_link->pl_id);
  598                 pci_print_irqmask(realmask);
  599                 printf("\n");
  600         }
  601         return (irq);
  602 }
  603 
  604 static void
  605 pci_print_irqmask(u_int16_t irqs)
  606 {
  607         int i, first;
  608 
  609         if (irqs == 0) {
  610                 printf("none");
  611                 return;
  612         }
  613         first = 1;
  614         for (i = 0; i < 16; i++, irqs >>= 1)
  615                 if (irqs & 1) {
  616                         if (!first)
  617                                 printf(" ");
  618                         else
  619                                 first = 0;
  620                         printf("%d", i);
  621                 }
  622 }
  623 
  624 /*
  625  * Display link devices.
  626  */
  627 static void
  628 pci_pir_dump_links(void)
  629 {
  630         struct pci_link *pci_link;
  631 
  632         printf("Link  IRQ  Rtd  Ref  IRQs\n");
  633         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  634                 printf("%#4x  %3d   %c   %3d  ", pci_link->pl_id,
  635                     pci_link->pl_irq, pci_link->pl_routed ? 'Y' : 'N',
  636                     pci_link->pl_references);
  637                 pci_print_irqmask(pci_link->pl_irqmask);
  638                 printf("\n");
  639         }
  640 }
  641 
  642 /*
  643  * See if any interrupts for a given PCI bus are routed in the PIR.  Don't
  644  * even bother looking if the BIOS doesn't support routing anyways.  If we
  645  * are probing a PCI-PCI bridge, then require_parse will be true and we should
  646  * only succeed if a host-PCI bridge has already attached and parsed the PIR.
  647  */
  648 int
  649 pci_pir_probe(int bus, int require_parse)
  650 {
  651         int i;
  652 
  653         if (pci_route_table == NULL || (require_parse && !pir_parsed))
  654                 return (0);
  655         for (i = 0; i < pci_route_count; i++)
  656                 if (pci_route_table->pt_entry[i].pe_bus == bus)
  657                         return (1);
  658         return (0);
  659 }
  660 
  661 /*
  662  * The driver for the new-bus psuedo device pir0 for the $PIR table.
  663  */
  664 
  665 static int
  666 pir_probe(device_t dev)
  667 {
  668         char buf[64];
  669 
  670         snprintf(buf, sizeof(buf), "PCI Interrupt Routing Table: %d Entries",
  671             pci_route_count);
  672         device_set_desc_copy(dev, buf);
  673         return (0);
  674 }
  675 
  676 static int
  677 pir_attach(device_t dev)
  678 {
  679 
  680         pci_pir_parse();
  681         KASSERT(pir_device == NULL, ("Multiple pir devices"));
  682         pir_device = dev;
  683         return (0);
  684 }
  685 
  686 static void
  687 pir_resume_find_device(struct PIR_entry *entry, struct PIR_intpin *intpin,
  688     void *arg)
  689 {
  690         struct pci_dev_lookup *pd;
  691 
  692         pd = (struct pci_dev_lookup *)arg;
  693         if (intpin->link != pd->link || pd->bus != -1)
  694                 return;
  695         pd->bus = entry->pe_bus;
  696         pd->device = entry->pe_device;
  697         pd->pin = intpin - entry->pe_intpin;
  698 }
  699 
  700 static int
  701 pir_resume(device_t dev)
  702 {
  703         struct pci_dev_lookup pd;
  704         struct pci_link *pci_link;
  705         int error;
  706 
  707         /* Ask the BIOS to re-route each link that was already routed. */
  708         TAILQ_FOREACH(pci_link, &pci_links, pl_links) {
  709                 if (!PCI_INTERRUPT_VALID(pci_link->pl_irq)) {
  710                         KASSERT(!pci_link->pl_routed,
  711                             ("link %#x is routed but has invalid PCI IRQ",
  712                             pci_link->pl_id));
  713                         continue;
  714                 }
  715                 if (pci_link->pl_routed) {
  716                         pd.bus = -1;
  717                         pd.link = pci_link->pl_id;
  718                         pci_pir_walk_table(pir_resume_find_device, &pd);
  719                         KASSERT(pd.bus != -1,
  720                 ("did not find matching entry for link %#x in the $PIR table",
  721                             pci_link->pl_id));
  722                         if (bootverbose)
  723                                 device_printf(dev,
  724                             "Using %d.%d.INT%c to route link %#x to IRQ %d\n",
  725                                     pd.bus, pd.device, pd.pin + 'A',
  726                                     pci_link->pl_id, pci_link->pl_irq);
  727                         error = pci_pir_biosroute(pd.bus, pd.device, 0, pd.pin,
  728                             pci_link->pl_irq);
  729                         if (error)
  730                                 device_printf(dev,
  731                             "ROUTE_INTERRUPT on resume for link %#x failed.\n",
  732                                     pci_link->pl_id);
  733                 }
  734         }
  735         return (0);
  736 }
  737 
  738 static device_method_t pir_methods[] = {
  739         /* Device interface */
  740         DEVMETHOD(device_probe,         pir_probe),
  741         DEVMETHOD(device_attach,        pir_attach),
  742         DEVMETHOD(device_resume,        pir_resume),
  743 
  744         { 0, 0 }
  745 };
  746 
  747 static driver_t pir_driver = {
  748         "pir",
  749         pir_methods,
  750         1,
  751 };
  752 
  753 static devclass_t pir_devclass;
  754 
  755 DRIVER_MODULE(pir, legacy, pir_driver, pir_devclass, 0, 0);

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