The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/i386/pci/pci_cfgreg.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, Scott Long <scottl@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("$FreeBSD$");
   32 
   33 #include "opt_xbox.h"
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/bus.h>
   38 #include <sys/lock.h>
   39 #include <sys/kernel.h>
   40 #include <sys/mutex.h>
   41 #include <sys/malloc.h>
   42 #include <sys/queue.h>
   43 #include <sys/sysctl.h>
   44 #include <dev/pci/pcivar.h>
   45 #include <dev/pci/pcireg.h>
   46 #include <machine/pci_cfgreg.h>
   47 #include <machine/pc/bios.h>
   48 
   49 #include <vm/vm.h>
   50 #include <vm/vm_param.h>
   51 #include <vm/vm_kern.h>
   52 #include <vm/vm_extern.h>
   53 #include <vm/pmap.h>
   54 
   55 #ifdef XBOX
   56 #include <machine/xbox.h>
   57 #endif
   58 
   59 #define PRVERB(a) do {                                                  \
   60         if (bootverbose)                                                \
   61                 printf a ;                                              \
   62 } while(0)
   63 
   64 #define PCIE_CACHE 8
   65 struct pcie_cfg_elem {
   66         TAILQ_ENTRY(pcie_cfg_elem)      elem;
   67         vm_offset_t     vapage;
   68         vm_paddr_t      papage;
   69 };
   70 
   71 enum {
   72         CFGMECH_NONE = 0,
   73         CFGMECH_1,
   74         CFGMECH_2,
   75         CFGMECH_PCIE,
   76 };
   77 
   78 SYSCTL_DECL(_hw_pci);
   79 
   80 static TAILQ_HEAD(pcie_cfg_list, pcie_cfg_elem) pcie_list[MAXCPU];
   81 static uint64_t pcie_base;
   82 static int pcie_minbus, pcie_maxbus;
   83 static uint32_t pcie_badslots;
   84 static int cfgmech;
   85 static int devmax;
   86 static struct mtx pcicfg_mtx;
   87 static int mcfg_enable = 1;
   88 SYSCTL_INT(_hw_pci, OID_AUTO, mcfg, CTLFLAG_RDTUN, &mcfg_enable, 0,
   89     "Enable support for PCI-e memory mapped config access");
   90 
   91 static uint32_t pci_docfgregread(int bus, int slot, int func, int reg,
   92                     int bytes);
   93 static int      pcireg_cfgread(int bus, int slot, int func, int reg, int bytes);
   94 static void     pcireg_cfgwrite(int bus, int slot, int func, int reg, int data, int bytes);
   95 static int      pcireg_cfgopen(void);
   96 static int      pciereg_cfgread(int bus, unsigned slot, unsigned func,
   97                     unsigned reg, unsigned bytes);
   98 static void     pciereg_cfgwrite(int bus, unsigned slot, unsigned func,
   99                     unsigned reg, int data, unsigned bytes);
  100 
  101 /*
  102  * Some BIOS writers seem to want to ignore the spec and put
  103  * 0 in the intline rather than 255 to indicate none.  Some use
  104  * numbers in the range 128-254 to indicate something strange and
  105  * apparently undocumented anywhere.  Assume these are completely bogus
  106  * and map them to 255, which means "none".
  107  */
  108 static __inline int 
  109 pci_i386_map_intline(int line)
  110 {
  111         if (line == 0 || line >= 128)
  112                 return (PCI_INVALID_IRQ);
  113         return (line);
  114 }
  115 
  116 static u_int16_t
  117 pcibios_get_version(void)
  118 {
  119         struct bios_regs args;
  120 
  121         if (PCIbios.ventry == 0) {
  122                 PRVERB(("pcibios: No call entry point\n"));
  123                 return (0);
  124         }
  125         args.eax = PCIBIOS_BIOS_PRESENT;
  126         if (bios32(&args, PCIbios.ventry, GSEL(GCODE_SEL, SEL_KPL))) {
  127                 PRVERB(("pcibios: BIOS_PRESENT call failed\n"));
  128                 return (0);
  129         }
  130         if (args.edx != 0x20494350) {
  131                 PRVERB(("pcibios: BIOS_PRESENT didn't return 'PCI ' in edx\n"));
  132                 return (0);
  133         }
  134         return (args.ebx & 0xffff);
  135 }
  136 
  137 /* 
  138  * Initialise access to PCI configuration space 
  139  */
  140 int
  141 pci_cfgregopen(void)
  142 {
  143         static int              opened = 0;
  144         uint64_t                pciebar;
  145         u_int16_t               vid, did;
  146         u_int16_t               v;
  147 
  148         if (opened)
  149                 return (1);
  150 
  151         if (cfgmech == CFGMECH_NONE && pcireg_cfgopen() == 0)
  152                 return (0);
  153 
  154         v = pcibios_get_version();
  155         if (v > 0)
  156                 PRVERB(("pcibios: BIOS version %x.%02x\n", (v & 0xff00) >> 8,
  157                     v & 0xff));
  158         mtx_init(&pcicfg_mtx, "pcicfg", NULL, MTX_SPIN);
  159         opened = 1;
  160 
  161         /* $PIR requires PCI BIOS 2.10 or greater. */
  162         if (v >= 0x0210)
  163                 pci_pir_open();
  164 
  165         if (cfgmech == CFGMECH_PCIE)
  166                 return (1);     
  167 
  168         /*
  169          * Grope around in the PCI config space to see if this is a
  170          * chipset that is capable of doing memory-mapped config cycles.
  171          * This also implies that it can do PCIe extended config cycles.
  172          */
  173 
  174         /* Check for supported chipsets */
  175         vid = pci_cfgregread(0, 0, 0, PCIR_VENDOR, 2);
  176         did = pci_cfgregread(0, 0, 0, PCIR_DEVICE, 2);
  177         switch (vid) {
  178         case 0x8086:
  179                 switch (did) {
  180                 case 0x3590:
  181                 case 0x3592:
  182                         /* Intel 7520 or 7320 */
  183                         pciebar = pci_cfgregread(0, 0, 0, 0xce, 2) << 16;
  184                         pcie_cfgregopen(pciebar, 0, 255);
  185                         break;
  186                 case 0x2580:
  187                 case 0x2584:
  188                 case 0x2590:
  189                         /* Intel 915, 925, or 915GM */
  190                         pciebar = pci_cfgregread(0, 0, 0, 0x48, 4);
  191                         pcie_cfgregopen(pciebar, 0, 255);
  192                         break;
  193                 }
  194         }
  195 
  196         return(1);
  197 }
  198 
  199 static uint32_t
  200 pci_docfgregread(int bus, int slot, int func, int reg, int bytes)
  201 {
  202 
  203         if (cfgmech == CFGMECH_PCIE &&
  204             (bus >= pcie_minbus && bus <= pcie_maxbus) &&
  205             (bus != 0 || !(1 << slot & pcie_badslots)))
  206                 return (pciereg_cfgread(bus, slot, func, reg, bytes));
  207         else
  208                 return (pcireg_cfgread(bus, slot, func, reg, bytes));
  209 }
  210 
  211 /* 
  212  * Read configuration space register
  213  */
  214 u_int32_t
  215 pci_cfgregread(int bus, int slot, int func, int reg, int bytes)
  216 {
  217         uint32_t line;
  218 
  219         /*
  220          * Some BIOS writers seem to want to ignore the spec and put
  221          * 0 in the intline rather than 255 to indicate none.  The rest of
  222          * the code uses 255 as an invalid IRQ.
  223          */
  224         if (reg == PCIR_INTLINE && bytes == 1) {
  225                 line = pci_docfgregread(bus, slot, func, PCIR_INTLINE, 1);
  226                 return (pci_i386_map_intline(line));
  227         }
  228         return (pci_docfgregread(bus, slot, func, reg, bytes));
  229 }
  230 
  231 /* 
  232  * Write configuration space register 
  233  */
  234 void
  235 pci_cfgregwrite(int bus, int slot, int func, int reg, u_int32_t data, int bytes)
  236 {
  237 
  238         if (cfgmech == CFGMECH_PCIE &&
  239             (bus >= pcie_minbus && bus <= pcie_maxbus) &&
  240             (bus != 0 || !(1 << slot & pcie_badslots)))
  241                 pciereg_cfgwrite(bus, slot, func, reg, data, bytes);
  242         else
  243                 pcireg_cfgwrite(bus, slot, func, reg, data, bytes);
  244 }
  245 
  246 /* 
  247  * Configuration space access using direct register operations
  248  */
  249 
  250 /* enable configuration space accesses and return data port address */
  251 static int
  252 pci_cfgenable(unsigned bus, unsigned slot, unsigned func, int reg, int bytes)
  253 {
  254         int dataport = 0;
  255 
  256 #ifdef XBOX
  257         if (arch_i386_is_xbox) {
  258                 /*
  259                  * The Xbox MCPX chipset is a derivative of the nForce 1
  260                  * chipset. It almost has the same bus layout; some devices
  261                  * cannot be used, because they have been removed.
  262                  */
  263 
  264                 /*
  265                  * Devices 00:00.1 and 00:00.2 used to be memory controllers on
  266                  * the nForce chipset, but on the Xbox, using them will lockup
  267                  * the chipset.
  268                  */
  269                 if (bus == 0 && slot == 0 && (func == 1 || func == 2))
  270                         return dataport;
  271                 
  272                 /*
  273                  * Bus 1 only contains a VGA controller at 01:00.0. When you try
  274                  * to probe beyond that device, you only get garbage, which
  275                  * could cause lockups.
  276                  */
  277                 if (bus == 1 && (slot != 0 || func != 0))
  278                         return dataport;
  279                 
  280                 /*
  281                  * Bus 2 used to contain the AGP controller, but the Xbox MCPX
  282                  * doesn't have one. Probing it can cause lockups.
  283                  */
  284                 if (bus >= 2)
  285                         return dataport;
  286         }
  287 #endif
  288 
  289         if (bus <= PCI_BUSMAX
  290             && slot < devmax
  291             && func <= PCI_FUNCMAX
  292             && (unsigned)reg <= PCI_REGMAX
  293             && bytes != 3
  294             && (unsigned)bytes <= 4
  295             && (reg & (bytes - 1)) == 0) {
  296                 switch (cfgmech) {
  297                 case CFGMECH_PCIE:
  298                 case CFGMECH_1:
  299                         outl(CONF1_ADDR_PORT, (1U << 31)
  300                             | (bus << 16) | (slot << 11) 
  301                             | (func << 8) | (reg & ~0x03));
  302                         dataport = CONF1_DATA_PORT + (reg & 0x03);
  303                         break;
  304                 case CFGMECH_2:
  305                         outb(CONF2_ENABLE_PORT, 0xf0 | (func << 1));
  306                         outb(CONF2_FORWARD_PORT, bus);
  307                         dataport = 0xc000 | (slot << 8) | reg;
  308                         break;
  309                 }
  310         }
  311         return (dataport);
  312 }
  313 
  314 /* disable configuration space accesses */
  315 static void
  316 pci_cfgdisable(void)
  317 {
  318         switch (cfgmech) {
  319         case CFGMECH_PCIE:
  320         case CFGMECH_1:
  321                 /*
  322                  * Do nothing for the config mechanism 1 case.
  323                  * Writing a 0 to the address port can apparently
  324                  * confuse some bridges and cause spurious
  325                  * access failures.
  326                  */
  327                 break;
  328         case CFGMECH_2:
  329                 outb(CONF2_ENABLE_PORT, 0);
  330                 break;
  331         }
  332 }
  333 
  334 static int
  335 pcireg_cfgread(int bus, int slot, int func, int reg, int bytes)
  336 {
  337         int data = -1;
  338         int port;
  339 
  340         mtx_lock_spin(&pcicfg_mtx);
  341         port = pci_cfgenable(bus, slot, func, reg, bytes);
  342         if (port != 0) {
  343                 switch (bytes) {
  344                 case 1:
  345                         data = inb(port);
  346                         break;
  347                 case 2:
  348                         data = inw(port);
  349                         break;
  350                 case 4:
  351                         data = inl(port);
  352                         break;
  353                 }
  354                 pci_cfgdisable();
  355         }
  356         mtx_unlock_spin(&pcicfg_mtx);
  357         return (data);
  358 }
  359 
  360 static void
  361 pcireg_cfgwrite(int bus, int slot, int func, int reg, int data, int bytes)
  362 {
  363         int port;
  364 
  365         mtx_lock_spin(&pcicfg_mtx);
  366         port = pci_cfgenable(bus, slot, func, reg, bytes);
  367         if (port != 0) {
  368                 switch (bytes) {
  369                 case 1:
  370                         outb(port, data);
  371                         break;
  372                 case 2:
  373                         outw(port, data);
  374                         break;
  375                 case 4:
  376                         outl(port, data);
  377                         break;
  378                 }
  379                 pci_cfgdisable();
  380         }
  381         mtx_unlock_spin(&pcicfg_mtx);
  382 }
  383 
  384 /* check whether the configuration mechanism has been correctly identified */
  385 static int
  386 pci_cfgcheck(int maxdev)
  387 {
  388         uint32_t id, class;
  389         uint8_t header;
  390         uint8_t device;
  391         int port;
  392 
  393         if (bootverbose) 
  394                 printf("pci_cfgcheck:\tdevice ");
  395 
  396         for (device = 0; device < maxdev; device++) {
  397                 if (bootverbose) 
  398                         printf("%d ", device);
  399 
  400                 port = pci_cfgenable(0, device, 0, 0, 4);
  401                 id = inl(port);
  402                 if (id == 0 || id == 0xffffffff)
  403                         continue;
  404 
  405                 port = pci_cfgenable(0, device, 0, 8, 4);
  406                 class = inl(port) >> 8;
  407                 if (bootverbose)
  408                         printf("[class=%06x] ", class);
  409                 if (class == 0 || (class & 0xf870ff) != 0)
  410                         continue;
  411 
  412                 port = pci_cfgenable(0, device, 0, 14, 1);
  413                 header = inb(port);
  414                 if (bootverbose)
  415                         printf("[hdr=%02x] ", header);
  416                 if ((header & 0x7e) != 0)
  417                         continue;
  418 
  419                 if (bootverbose)
  420                         printf("is there (id=%08x)\n", id);
  421 
  422                 pci_cfgdisable();
  423                 return (1);
  424         }
  425         if (bootverbose) 
  426                 printf("-- nothing found\n");
  427 
  428         pci_cfgdisable();
  429         return (0);
  430 }
  431 
  432 static int
  433 pcireg_cfgopen(void)
  434 {
  435         uint32_t mode1res, oldval1;
  436         uint8_t mode2res, oldval2;
  437 
  438         /* Check for type #1 first. */
  439         oldval1 = inl(CONF1_ADDR_PORT);
  440 
  441         if (bootverbose) {
  442                 printf("pci_open(1):\tmode 1 addr port (0x0cf8) is 0x%08x\n",
  443                     oldval1);
  444         }
  445 
  446         cfgmech = CFGMECH_1;
  447         devmax = 32;
  448 
  449         outl(CONF1_ADDR_PORT, CONF1_ENABLE_CHK);
  450         DELAY(1);
  451         mode1res = inl(CONF1_ADDR_PORT);
  452         outl(CONF1_ADDR_PORT, oldval1);
  453 
  454         if (bootverbose)
  455                 printf("pci_open(1a):\tmode1res=0x%08x (0x%08lx)\n",  mode1res,
  456                     CONF1_ENABLE_CHK);
  457 
  458         if (mode1res) {
  459                 if (pci_cfgcheck(32)) 
  460                         return (cfgmech);
  461         }
  462 
  463         outl(CONF1_ADDR_PORT, CONF1_ENABLE_CHK1);
  464         mode1res = inl(CONF1_ADDR_PORT);
  465         outl(CONF1_ADDR_PORT, oldval1);
  466 
  467         if (bootverbose)
  468                 printf("pci_open(1b):\tmode1res=0x%08x (0x%08lx)\n",  mode1res,
  469                     CONF1_ENABLE_CHK1);
  470 
  471         if ((mode1res & CONF1_ENABLE_MSK1) == CONF1_ENABLE_RES1) {
  472                 if (pci_cfgcheck(32)) 
  473                         return (cfgmech);
  474         }
  475 
  476         /* Type #1 didn't work, so try type #2. */
  477         oldval2 = inb(CONF2_ENABLE_PORT);
  478 
  479         if (bootverbose) {
  480                 printf("pci_open(2):\tmode 2 enable port (0x0cf8) is 0x%02x\n",
  481                     oldval2);
  482         }
  483 
  484         if ((oldval2 & 0xf0) == 0) {
  485 
  486                 cfgmech = CFGMECH_2;
  487                 devmax = 16;
  488 
  489                 outb(CONF2_ENABLE_PORT, CONF2_ENABLE_CHK);
  490                 mode2res = inb(CONF2_ENABLE_PORT);
  491                 outb(CONF2_ENABLE_PORT, oldval2);
  492 
  493                 if (bootverbose)
  494                         printf("pci_open(2a):\tmode2res=0x%02x (0x%02x)\n", 
  495                             mode2res, CONF2_ENABLE_CHK);
  496 
  497                 if (mode2res == CONF2_ENABLE_RES) {
  498                         if (bootverbose)
  499                                 printf("pci_open(2a):\tnow trying mechanism 2\n");
  500 
  501                         if (pci_cfgcheck(16)) 
  502                                 return (cfgmech);
  503                 }
  504         }
  505 
  506         /* Nothing worked, so punt. */
  507         cfgmech = CFGMECH_NONE;
  508         devmax = 0;
  509         return (cfgmech);
  510 }
  511 
  512 int
  513 pcie_cfgregopen(uint64_t base, uint8_t minbus, uint8_t maxbus)
  514 {
  515         struct pcie_cfg_list *pcielist;
  516         struct pcie_cfg_elem *pcie_array, *elem;
  517 #ifdef SMP
  518         struct pcpu *pc;
  519 #endif
  520         vm_offset_t va;
  521         uint32_t val1, val2;
  522         int i, slot;
  523 
  524         if (!mcfg_enable)
  525                 return (0);
  526 
  527         if (minbus != 0)
  528                 return (0);
  529 
  530 #ifndef PAE
  531         if (base >= 0x100000000) {
  532                 if (bootverbose)
  533                         printf(
  534             "PCI: Memory Mapped PCI configuration area base 0x%jx too high\n",
  535                             (uintmax_t)base);
  536                 return (0);
  537         }
  538 #endif
  539                 
  540         if (bootverbose)
  541                 printf("PCIe: Memory Mapped configuration base @ 0x%jx\n",
  542                     (uintmax_t)base);
  543 
  544 #ifdef SMP
  545         STAILQ_FOREACH(pc, &cpuhead, pc_allcpu)
  546 #endif
  547         {
  548 
  549                 pcie_array = malloc(sizeof(struct pcie_cfg_elem) * PCIE_CACHE,
  550                     M_DEVBUF, M_NOWAIT);
  551                 if (pcie_array == NULL)
  552                         return (0);
  553 
  554                 va = kva_alloc(PCIE_CACHE * PAGE_SIZE);
  555                 if (va == 0) {
  556                         free(pcie_array, M_DEVBUF);
  557                         return (0);
  558                 }
  559 
  560 #ifdef SMP
  561                 pcielist = &pcie_list[pc->pc_cpuid];
  562 #else
  563                 pcielist = &pcie_list[0];
  564 #endif
  565                 TAILQ_INIT(pcielist);
  566                 for (i = 0; i < PCIE_CACHE; i++) {
  567                         elem = &pcie_array[i];
  568                         elem->vapage = va + (i * PAGE_SIZE);
  569                         elem->papage = 0;
  570                         TAILQ_INSERT_HEAD(pcielist, elem, elem);
  571                 }
  572         }
  573 
  574         pcie_base = base;
  575         pcie_minbus = minbus;
  576         pcie_maxbus = maxbus;
  577         cfgmech = CFGMECH_PCIE;
  578         devmax = 32;
  579 
  580         /*
  581          * On some AMD systems, some of the devices on bus 0 are
  582          * inaccessible using memory-mapped PCI config access.  Walk
  583          * bus 0 looking for such devices.  For these devices, we will
  584          * fall back to using type 1 config access instead.
  585          */
  586         if (pci_cfgregopen() != 0) {
  587                 for (slot = 0; slot <= PCI_SLOTMAX; slot++) {
  588                         val1 = pcireg_cfgread(0, slot, 0, 0, 4);
  589                         if (val1 == 0xffffffff)
  590                                 continue;
  591 
  592                         val2 = pciereg_cfgread(0, slot, 0, 0, 4);
  593                         if (val2 != val1)
  594                                 pcie_badslots |= (1 << slot);
  595                 }
  596         }
  597 
  598         return (1);
  599 }
  600 
  601 #define PCIE_PADDR(base, reg, bus, slot, func)  \
  602         ((base)                         +       \
  603         ((((bus) & 0xff) << 20)         |       \
  604         (((slot) & 0x1f) << 15)         |       \
  605         (((func) & 0x7) << 12)          |       \
  606         ((reg) & 0xfff)))
  607 
  608 static __inline vm_offset_t
  609 pciereg_findaddr(int bus, unsigned slot, unsigned func, unsigned reg)
  610 {
  611         struct pcie_cfg_list *pcielist;
  612         struct pcie_cfg_elem *elem;
  613         vm_paddr_t pa, papage;
  614 
  615         pa = PCIE_PADDR(pcie_base, reg, bus, slot, func);
  616         papage = pa & ~PAGE_MASK;
  617 
  618         /*
  619          * Find an element in the cache that matches the physical page desired,
  620          * or create a new mapping from the least recently used element.
  621          * A very simple LRU algorithm is used here, does it need to be more
  622          * efficient?
  623          */
  624         pcielist = &pcie_list[PCPU_GET(cpuid)];
  625         TAILQ_FOREACH(elem, pcielist, elem) {
  626                 if (elem->papage == papage)
  627                         break;
  628         }
  629 
  630         if (elem == NULL) {
  631                 elem = TAILQ_LAST(pcielist, pcie_cfg_list);
  632                 if (elem->papage != 0) {
  633                         pmap_kremove(elem->vapage);
  634                         invlpg(elem->vapage);
  635                 }
  636                 pmap_kenter(elem->vapage, papage);
  637                 elem->papage = papage;
  638         }
  639 
  640         if (elem != TAILQ_FIRST(pcielist)) {
  641                 TAILQ_REMOVE(pcielist, elem, elem);
  642                 TAILQ_INSERT_HEAD(pcielist, elem, elem);
  643         }
  644         return (elem->vapage | (pa & PAGE_MASK));
  645 }
  646 
  647 /*
  648  * AMD BIOS And Kernel Developer's Guides for CPU families starting with 10h
  649  * have a requirement that all accesses to the memory mapped PCI configuration
  650  * space are done using AX class of registers.
  651  * Since other vendors do not currently have any contradicting requirements
  652  * the AMD access pattern is applied universally.
  653  */
  654 
  655 static int
  656 pciereg_cfgread(int bus, unsigned slot, unsigned func, unsigned reg,
  657     unsigned bytes)
  658 {
  659         vm_offset_t va;
  660         int data = -1;
  661 
  662         if (bus < pcie_minbus || bus > pcie_maxbus || slot > PCI_SLOTMAX ||
  663             func > PCI_FUNCMAX || reg > PCIE_REGMAX)
  664                 return (-1);
  665 
  666         critical_enter();
  667         va = pciereg_findaddr(bus, slot, func, reg);
  668 
  669         switch (bytes) {
  670         case 4:
  671                 __asm("movl %1, %0" : "=a" (data)
  672                     : "m" (*(volatile uint32_t *)va));
  673                 break;
  674         case 2:
  675                 __asm("movzwl %1, %0" : "=a" (data)
  676                     : "m" (*(volatile uint16_t *)va));
  677                 break;
  678         case 1:
  679                 __asm("movzbl %1, %0" : "=a" (data)
  680                     : "m" (*(volatile uint8_t *)va));
  681                 break;
  682         }
  683 
  684         critical_exit();
  685         return (data);
  686 }
  687 
  688 static void
  689 pciereg_cfgwrite(int bus, unsigned slot, unsigned func, unsigned reg, int data,
  690     unsigned bytes)
  691 {
  692         vm_offset_t va;
  693 
  694         if (bus < pcie_minbus || bus > pcie_maxbus || slot > PCI_SLOTMAX ||
  695             func > PCI_FUNCMAX || reg > PCIE_REGMAX)
  696                 return;
  697 
  698         critical_enter();
  699         va = pciereg_findaddr(bus, slot, func, reg);
  700 
  701         switch (bytes) {
  702         case 4:
  703                 __asm("movl %1, %0" : "=m" (*(volatile uint32_t *)va)
  704                     : "a" (data));
  705                 break;
  706         case 2:
  707                 __asm("movw %1, %0" : "=m" (*(volatile uint16_t *)va)
  708                     : "a" ((uint16_t)data));
  709                 break;
  710         case 1:
  711                 __asm("movb %1, %0" : "=m" (*(volatile uint8_t *)va)
  712                     : "a" ((uint8_t)data));
  713                 break;
  714         }
  715 
  716         critical_exit();
  717 }

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