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windows-xp/Source/XPSP1/NT/base/hals/halmps/i386/mpaddr.c

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/*++
Copyright (c) 1991 Microsoft Corporation
All rights reserved
Module Name:
mpaddr.c
Abstract:
Author:
Ken Reneris
Environment:
Kernel mode only.
Revision History:
*/
#include "halp.h"
#include "apic.inc"
#include "pcmp_nt.inc"
#include "pci.h"
#if DEBUGGING
#include "stdio.h"
#endif
#define STATIC // functions used internal to this module
#define KEY_VALUE_BUFFER_SIZE 1024
#if DBG
extern ULONG HalDebug;
#endif
extern struct HalpMpInfo HalpMpInfoTable;
extern USHORT HalpIoCompatibleRangeList0[];
extern USHORT HalpIoCompatibleRangeList1[];
extern BOOLEAN HalpPciLockSettings;
extern WCHAR HalpSzSystem[];
struct PcMpTable *PcMpTablePtr;
BOOLEAN
HalpTranslateIsaBusAddress (
IN PVOID BusHandler,
IN PVOID RootHandler,
IN PHYSICAL_ADDRESS BusAddress,
IN OUT PULONG AddressSpace,
OUT PPHYSICAL_ADDRESS TranslatedAddress
);
ULONG
HalpNoBusData (
IN PVOID BusHandler,
IN PVOID RootHandler,
IN ULONG SlotNumber,
IN PVOID Buffer,
IN ULONG Offset,
IN ULONG Length
);
HalpGetEisaData (
IN PVOID BusHandler,
IN PVOID RootHandler,
IN ULONG SlotNumber,
IN PVOID Buffer,
IN ULONG Offset,
IN ULONG Length
);
NTSTATUS
HalpAdjustEisaResourceList (
IN PVOID BusHandler,
IN PVOID RootHandler,
IN OUT PIO_RESOURCE_REQUIREMENTS_LIST *pResourceList
);
ULONG
HalpGetEisaInterruptVector (
IN PVOID BusHandler,
IN PVOID RootHandler,
IN ULONG BusInterruptLevel,
IN ULONG BusInterruptVector,
OUT PKIRQL Irql,
OUT PKAFFINITY Affinity
);
// --------------------------------------------------------------------
VOID
HalpInitBusAddressMapInfo (
VOID
);
STATIC PSUPPORTED_RANGES
HalpBuildBusAddressMap (
IN UCHAR MpsBusId
);
PBUS_HANDLER
HalpLookupCreateHandlerForBus (
IN PPCMPBUSTRANS pBusType,
IN ULONG BusNo
);
VOID
HalpInheritBusAddressMapInfo (
VOID
);
BOOLEAN
HalpMPSBusId2NtBusId (
IN UCHAR ApicBusId,
OUT PPCMPBUSTRANS *ppBusType,
OUT PULONG BusNo
);
STATIC PSUPPORTED_RANGES
HalpMergeRangesFromParent (
PSUPPORTED_RANGES CurrentList,
UCHAR MpsBusId
);
#if DEBUGGING
VOID
HalpDisplayBusInformation (
PBUS_HANDLER Bus
);
#endif
//
// Internal prototypes
//
struct {
ULONG Offset;
UCHAR MpsType;
} HalpMpsRangeList[] = {
FIELD_OFFSET (SUPPORTED_RANGES, IO), MPS_ADDRESS_MAP_IO,
FIELD_OFFSET (SUPPORTED_RANGES, Memory), MPS_ADDRESS_MAP_MEMORY,
FIELD_OFFSET (SUPPORTED_RANGES, PrefetchMemory),MPS_ADDRESS_MAP_PREFETCH_MEMORY,
FIELD_OFFSET (SUPPORTED_RANGES, Dma), MPS_ADDRESS_MAP_UNDEFINED,
0, MPS_ADDRESS_MAP_UNDEFINED
};
#define RANGE_LIST(a,i) ((PSUPPORTED_RANGE) ((PUCHAR) a + HalpMpsRangeList[i].Offset))
#ifdef ALLOC_PRAGMA
#pragma alloc_text(INIT,HalpInitBusAddressMapInfo)
#pragma alloc_text(INIT,HalpBuildBusAddressMap)
#pragma alloc_text(INIT,HalpInheritBusAddressMapInfo)
#pragma alloc_text(INIT,HalpMergeRangesFromParent)
#pragma alloc_text(INIT,HalpLookupCreateHandlerForBus)
#pragma alloc_text(PAGE,HalpAllocateNewRangeList)
#pragma alloc_text(PAGE,HalpFreeRangeList)
#pragma alloc_text(PAGE,HalpMpsGetParentBus)
#pragma alloc_text(PAGE,HalpMpsBusIsRootBus)
#endif
VOID
HalpInitBusAddressMapInfo (
VOID
)
/*++
Routine Description:
Reads MPS bus addressing mapping table, and builds/replaces the
supported address range mapping for the given bus.
Note there's a little slop in this function as it doesn't reclaim
memory allocated before this function is called, which it replaces
pointers too.
--*/
{
ULONG BusNo;
PPCMPBUSTRANS pBusType;
PMPS_EXTENTRY ExtTable2, ExtTable;
PBUS_HANDLER Handler;
PSUPPORTED_RANGES Addresses;
ULONG i;
BOOLEAN Processed;
//
// Check for any address mapping information for the buses
//
// Note: We assume that if any MPS bus address map information
// is found for a bus, that the MPS bios will supply all the
// valid IO, Memory, and prefetch memory addresses for that BUS.
// The bios can not supply some address tyeps for a given bus
// without supplying them all.
//
ExtTable = HalpMpInfoTable.ExtensionTable;
while (ExtTable < HalpMpInfoTable.EndOfExtensionTable) {
//
// Is this an address map entry?
//
if (ExtTable->Type == EXTTYPE_BUS_ADDRESS_MAP) {
//
// See if this bus has already been processed
//
Processed = FALSE;
ExtTable2 = HalpMpInfoTable.ExtensionTable;
while (ExtTable2 < ExtTable) {
if (ExtTable2->Type == EXTTYPE_BUS_ADDRESS_MAP &&
ExtTable2->u.AddressMap.BusId == ExtTable->u.AddressMap.BusId) {
Processed = TRUE;
break;
}
ExtTable2 = (PMPS_EXTENTRY) (((PUCHAR) ExtTable2) + ExtTable2->Length);
}
//
// Determine the NT bus this map info is for
//
if (!Processed &&
HalpMPSBusId2NtBusId (ExtTable->u.AddressMap.BusId, &pBusType, &BusNo)) {
//
// Lookup the bushander for the bus
//
Handler = HalpLookupCreateHandlerForBus (pBusType, BusNo);
if (Handler) {
//
// NOTE: Until we get better kernel PnP support, for now
// limit the ability of the system to move already BIOS
// initialized devices. This is needed because the exteneded
// express BIOS can't give the OS any breathing space when
// it hands bus supported ranges, and there's currently not
// an interface to the kernel to obtain current PCI device
// settings. (fixed in the future.)
//
HalpPciLockSettings = TRUE;
//
// Build BusAddress Map for this MPS bus
//
Addresses = HalpBuildBusAddressMap (ExtTable->u.AddressMap.BusId);
//
// Consoladate ranges
//
HalpConsolidateRanges (Addresses);
//
// Use current ranges for any undefined MPS ranges
//
for (i=0; HalpMpsRangeList[i].Offset; i++) {
if (HalpMpsRangeList[i].MpsType == MPS_ADDRESS_MAP_UNDEFINED) {
*RANGE_LIST(Addresses,i) = *RANGE_LIST(Handler->BusAddresses, i);
}
}
//
// Set bus'es support addresses
//
Handler->BusAddresses = Addresses;
} else {
DBGMSG ("HAL: Initialize BUS address map - bus not an registered NT bus\n");
}
}
}
ExtTable = (PMPS_EXTENTRY) (((PUCHAR) ExtTable) + ExtTable->Length);
}
}
STATIC PSUPPORTED_RANGES
HalpBuildBusAddressMap (
IN UCHAR MpsBusId
)
/*++
Routine Description:
Builds a SUPPORT_RANGES list for the supplied Mps Bus Id, by
MPS bus addressing mapping descriptors.
Note this function does not include any information contained
in the MPS bus hierarchy descriptors.
Arguments:
MpsBusId - mps bus id of bus to build address map for.
Return:
The bus'es supported ranges as defined by the MPS bus
address mapping descriptors
--*/
{
PMPS_EXTENTRY ExtTable;
PSUPPORTED_RANGES Addresses;
PSUPPORTED_RANGE HRange, Range;
ULONG i, j, k;
ULONG Base, Limit, AddressSpace;
PUSHORT CompatibleList;
Addresses = HalpAllocateNewRangeList();
ExtTable = HalpMpInfoTable.ExtensionTable;
while (ExtTable < HalpMpInfoTable.EndOfExtensionTable) {
//
// Is this an address map entry for the proper bus?
//
if (ExtTable->Type == EXTTYPE_BUS_ADDRESS_MAP &&
ExtTable->u.AddressMap.BusId == MpsBusId) {
//
// Find range type
//
for (i=0; HalpMpsRangeList[i].Offset; i++) {
if (HalpMpsRangeList[i].MpsType == ExtTable->u.AddressMap.Type) {
HRange = RANGE_LIST(Addresses, i);
break;
}
}
AddressSpace = HalpMpsRangeList[i].MpsType == MPS_ADDRESS_MAP_IO ? 1 : 0;
if (HalpMpsRangeList[i].Offset) {
HalpAddRange (
HRange,
AddressSpace,
0, // SystemBase
ExtTable->u.AddressMap.Base,
ExtTable->u.AddressMap.Base + ExtTable->u.AddressMap.Length - 1
);
} else {
DBGMSG ("HALMPS: Unkown address range type in MPS table\n");
}
}
ExtTable = (PMPS_EXTENTRY) (((PUCHAR) ExtTable) + ExtTable->Length);
}
//
// See if the BIOS wants to modify the buses supported addresses with
// some pre-defined default information. (yes, another case where the
// bios wants to be lazy.)
//
ExtTable = HalpMpInfoTable.ExtensionTable;
while (ExtTable < HalpMpInfoTable.EndOfExtensionTable) {
//
// Is this an CompatibleMap entry for the proper bus?
//
if (ExtTable->Type == EXTTYPE_BUS_COMPATIBLE_MAP &&
ExtTable->u.CompatibleMap.BusId == MpsBusId) {
//
// All currently defined default tables are for IO ranges,
// we'll use that assumption here.
//
i = 0;
ASSERT (HalpMpsRangeList[i].MpsType == MPS_ADDRESS_MAP_IO);
HRange = RANGE_LIST(Addresses, i);
AddressSpace = 1;
CompatibleList = NULL;
switch (ExtTable->u.CompatibleMap.List) {
case 0: CompatibleList = HalpIoCompatibleRangeList0; break;
case 1: CompatibleList = HalpIoCompatibleRangeList1; break;
default: DBGMSG ("HAL: Unknown compatible range list\n"); continue; break;
}
for (j=0; j < 0x10; j++) {
for (k=0; CompatibleList[k]; k += 2) {
Base = (j << 12) | CompatibleList[k];
Limit = (j << 12) | CompatibleList[k+1];
if (ExtTable->u.CompatibleMap.Modifier) {
HalpRemoveRange (HRange, Base, Limit);
} else {
HalpAddRange (HRange, AddressSpace, 0, Base, Limit);
}
}
}
}
ExtTable = (PMPS_EXTENTRY) (((PUCHAR) ExtTable) + ExtTable->Length);
}
return Addresses;
}
NTSTATUS
HalpAddEisaBus (
PBUS_HANDLER Bus
)
/*++
Routine Description:
Adds another EISA bus handler to the system.
Note: this is used for ISA buses as well - they are added as eisa
buses, then cloned into isa bus handlers
--*/
{
Bus->GetBusData = HalpGetEisaData;
Bus->GetInterruptVector = HalpGetEisaInterruptVector;
Bus->AdjustResourceList = HalpAdjustEisaResourceList;
Bus->BusAddresses->Version = BUS_SUPPORTED_RANGE_VERSION;
Bus->BusAddresses->Dma.Limit = 7;
Bus->BusAddresses->Memory.Limit = 0xFFFFFFFF;
Bus->BusAddresses->IO.Limit = 0xFFFF;
Bus->BusAddresses->IO.SystemAddressSpace = 1;
Bus->BusAddresses->PrefetchMemory.Base = 1;
return STATUS_SUCCESS;
}
NTSTATUS
HalpAddPciBus (
PBUS_HANDLER Bus
)
{
//
// The firmware should have informed NT how many PCI buses
// there where at NtDetect time
//
DBGMSG ("HAL: BIOS problem. PCI bus must be report via IS_PCI_PRESENT bios call\n");
return STATUS_UNSUCCESSFUL;
}
PBUS_HANDLER
HalpLookupCreateHandlerForBus (
IN PPCMPBUSTRANS pBusType,
IN ULONG BusNo
)
{
NTSTATUS Status;
PBUS_HANDLER Handler;
Handler = HaliHandlerForBus (pBusType->NtType, BusNo);
if (!Handler && pBusType->NewInstance) {
//
// This bus does not exist, but we know how to add it.
//
Status = HalRegisterBusHandler (
pBusType->NtType,
pBusType->NtConfig,
BusNo,
Internal, // parent bus
0,
pBusType->BusExtensionSize,
pBusType->NewInstance,
&Handler
);
if (!NT_SUCCESS(Status)) {
Handler = NULL;
}
}
return Handler;
}
VOID
HalpDetectInvalidAddressOverlaps(
VOID
)
{
ULONG i, j, k;
PBUS_HANDLER Bus1, Bus2;
PSUPPORTED_RANGE Entry;
PSUPPORTED_RANGES NewRange;
//
// Find root PCI buses and detect invalid address overlaps
//
for(i=0; Bus1 = HaliHandlerForBus(PCIBus, i); ++i) {
if (((Bus1->ParentHandler) &&
(Bus1->ParentHandler->InterfaceType != Internal)) ||
!(Bus1->BusAddresses)) {
continue;
}
for(j=i+1; Bus2 = HaliHandlerForBus(PCIBus, j); ++j) {
if (((Bus2->ParentHandler) &&
(Bus2->ParentHandler->InterfaceType != Internal)) ||
!(Bus2->BusAddresses)) {
continue;
}
NewRange = HalpMergeRanges(Bus1->BusAddresses, Bus2->BusAddresses);
HalpConsolidateRanges(NewRange);
for(k=0; HalpMpsRangeList[k].Offset; k++) {
Entry = RANGE_LIST(NewRange, k);
while (Entry) {
if (Entry->Limit != 0) {
// KeBugCheck(HAL_INITIALIZATION_FAILED);
DbgPrint("HalpDetectInvalidAddressOverlaps: Address Overlap Detected\n");
break;
} else {
Entry = Entry->Next;
}
}
}
HalpFreeRangeList(NewRange);
}
}
}
VOID
HalpInheritBusAddressMapInfo (
VOID
)
/*++
Routine Description:
Reads MPS bus hierarchy descriptors and inherits any implied bus
address mapping information.
Note there's a little slop in this function as it doesn't reclaim
memory allocated before this function is called, which it replaces
pointers too.
--*/
{
ULONG BusNo, i, j;
PPCMPBUSTRANS pBusType;
PMPS_EXTENTRY ExtTable;
PBUS_HANDLER Bus, Bus2;
PSUPPORTED_RANGES Addresses;
PUCHAR p;
//
// Search for any bus hierarchy descriptors and inherit supported address
// ranges accordingly.
//
ExtTable = HalpMpInfoTable.ExtensionTable;
while (ExtTable < HalpMpInfoTable.EndOfExtensionTable) {
//
// Is this a bus hierarchy descriptor?
//
if (ExtTable->Type == EXTTYPE_BUS_HIERARCHY) {
//
// Determine the NT bus
//
if (HalpMPSBusId2NtBusId (ExtTable->u.BusHierarchy.BusId, &pBusType, &BusNo)) {
Bus = HalpLookupCreateHandlerForBus (pBusType, BusNo);
if (Bus) {
//
// Get ranges from parent
//
Addresses = HalpMergeRangesFromParent (
Bus->BusAddresses,
ExtTable->u.BusHierarchy.ParentBusId
);
//
// Set bus'es support addresses
//
Bus->BusAddresses = HalpConsolidateRanges (Addresses);
} else {
DBGMSG ("HAL: Inherit BUS address map - bus not an registered NT bus\n");
}
} else {
DBGMSG ("HAL: Inherit BUS address map - unkown MPS bus type\n");
}
}
ExtTable = (PMPS_EXTENTRY) (((PUCHAR) ExtTable) + ExtTable->Length);
}
//
// Clone EISA bus ranges to matching ISA buses
//
BusNo = 0;
for (; ;) {
Bus = HaliHandlerForBus(Eisa, BusNo);
Bus2 = HaliHandlerForBus(Isa , BusNo);
if (!Bus) {
break;
}
if (!Bus2) {
//
// Matching ISA bus didn't exist, create it
//
HalRegisterBusHandler (
Isa,
ConfigurationSpaceUndefined,
BusNo,
Eisa, // parent bus
BusNo,
0,
NULL,
&Bus2
);
Bus2->GetBusData = HalpNoBusData;
Bus2->TranslateBusAddress = HalpTranslateIsaBusAddress;
}
//
// Copy its parent bus ranges
//
Addresses = HalpCopyRanges (Bus->BusAddresses);
//
// Pull out memory ranges above the isa 24 bit supported ranges
//
HalpRemoveRange (
&Addresses->Memory,
0x1000000,
0x7FFFFFFFFFFFFFFF
);
HalpRemoveRange (
&Addresses->PrefetchMemory,
0x1000000,
0x7FFFFFFFFFFFFFFF
);
Bus2->BusAddresses = HalpConsolidateRanges (Addresses);
BusNo += 1;
}
//
// Inherit any implied interrupt routing from parent PCI buses
//
HalpMPSPCIChildren ();
HalpDetectInvalidAddressOverlaps();
#if DBG
if (HalDebug) {
HalpDisplayAllBusRanges ();
}
#endif
}
STATIC PSUPPORTED_RANGES
HalpMergeRangesFromParent (
IN PSUPPORTED_RANGES CurrentList,
IN UCHAR MpsBusId
)
/*++
Routine Description:
Shrinks this CurrentList to include only the ranges also
supported by the supplied MPS bus id.
Arguments:
CurrentList - Current supported range list
MpsBusId - mps bus id of bus to merge with
Return:
The bus'es supported ranges as defined by the orignal list,
shrunk by all parents buses supported ranges as defined by
the MPS hierarchy descriptors
--*/
{
ULONG BusNo;
PPCMPBUSTRANS pBusType;
PMPS_EXTENTRY ExtTable;
PBUS_HANDLER Bus;
PSUPPORTED_RANGES NewList, MergeList, MpsBusList;
BOOLEAN FoundParentBus;
ULONG i;
FoundParentBus = FALSE;
MergeList = NULL;
MpsBusList = NULL;
//
// Determine the NT bus
//
if (HalpMPSBusId2NtBusId (MpsBusId, &pBusType, &BusNo)) {
//
// Lookup the bushander for the bus
//
Bus = HaliHandlerForBus (pBusType->NtType, BusNo);
if (Bus) {
MergeList = Bus->BusAddresses;
}
}
//
// If NT bus not found, use supported range list from MPS bus
// address map descriptors
//
if (!MergeList) {
MpsBusList = HalpBuildBusAddressMap(MpsBusId);
MergeList = MpsBusList;
}
//
// If no list to merge with use CurrentList
//
if (!MergeList) {
return CurrentList;
}
if (!CurrentList) {
//
// If no CurrentList, then nothing to merge with
//
NewList = HalpCopyRanges (MergeList);
} else {
//
// Merge lists together and build a new list
//
NewList = HalpMergeRanges (
CurrentList,
MergeList
);
//
// MPS doesn't define DMA ranges, so we don't
// merge those down.. Add valid DMA ranges back
//
HalpAddRangeList (&NewList->Dma, &CurrentList->Dma);
}
//
// See if bus has parent bus listed in the bus hierarchy descriptors
//
ExtTable = HalpMpInfoTable.ExtensionTable;
while (ExtTable < HalpMpInfoTable.EndOfExtensionTable) {
if (ExtTable->Type == EXTTYPE_BUS_HIERARCHY &&
ExtTable->u.BusHierarchy.BusId == MpsBusId) {
//
// BIOS can only list one parent per bus
//
ASSERT (FoundParentBus == FALSE);
FoundParentBus = TRUE;
//
// Merge current list with parent's supported range list
//
CurrentList = NewList;
NewList = HalpMergeRangesFromParent (
CurrentList,
ExtTable->u.BusHierarchy.ParentBusId
);
//
// Free old list
//
HalpFreeRangeList (CurrentList);
}
ExtTable = (PMPS_EXTENTRY) (((PUCHAR) ExtTable) + ExtTable->Length);
}
//
// Clean up
//
if (MpsBusList) {
HalpFreeRangeList (MpsBusList);
}
return NewList;
}
NTSTATUS
HalpMpsGetParentBus(
IN UCHAR MpsBus,
OUT UCHAR *ParentMpsBus
)
{
PMPS_EXTENTRY ExtTable;
PAGED_CODE();
ExtTable = HalpMpInfoTable.ExtensionTable;
while (ExtTable < HalpMpInfoTable.EndOfExtensionTable) {
//
// Is this a bus hierarchy descriptor?
//
if (ExtTable->Type == EXTTYPE_BUS_HIERARCHY) {
if (ExtTable->u.BusHierarchy.BusId == MpsBus) {
*ParentMpsBus = ExtTable->u.BusHierarchy.ParentBusId;
return STATUS_SUCCESS;
}
}
ExtTable = (PMPS_EXTENTRY) (((PUCHAR) ExtTable) + ExtTable->Length);
}
return STATUS_NOT_FOUND;
}
BOOLEAN
HalpMpsBusIsRootBus(
IN UCHAR MpsBus
)
//
// The criteria for a Root Bus are as follows:
//
// 1.1 and 1.4 BIOS:
//
// 1) The bus is number 0.
//
//
// 1.4 BIOS only:
//
// 2) The bus does not have a parent.
//
// 3) The bus has address descriptors, if
// there are any present in the machine.
//
//
// 4) Last resort. Scan all possible parent busses
// looking for a bridge that generates this bus.
//
#define BRIDGE_HEADER_BUFFER_SIZE (FIELD_OFFSET(PCI_COMMON_CONFIG, u.type1.SubordinateBus) + 1)
{
NTSTATUS status;
UCHAR parentBus;
PMPS_EXTENTRY ExtTable;
BOOLEAN biosContainsAddressInfo = FALSE;
UCHAR parentPci, childPci;
PCI_SLOT_NUMBER bridgeSlot;
PCI_COMMON_CONFIG pciData;
ULONG bytesRead, d, f;
PPCMPBUSTRANS busType;
ULONG busNumber;
PAGED_CODE();
if (MpsBus == 0) {
return TRUE;
}
//
// Check to see if this MPS bus, though not
// itself numbered 0, represents a bus that
// is numbered 0.
//
if (HalpMPSBusId2NtBusId(MpsBus,
&busType,
&busNumber)) {
if (busNumber == 0) {
return TRUE;
}
}
if (PcMpTablePtr->Revision >= 4) {
if (NT_SUCCESS(HalpMpsGetParentBus(MpsBus,&parentBus))) {
return FALSE;
}
ExtTable = HalpMpInfoTable.ExtensionTable;
while (ExtTable < HalpMpInfoTable.EndOfExtensionTable) {
if ((ExtTable->Type == EXTTYPE_BUS_ADDRESS_MAP) ||
(ExtTable->Type == EXTTYPE_BUS_COMPATIBLE_MAP)) {
biosContainsAddressInfo = TRUE;
if (ExtTable->u.AddressMap.BusId == MpsBus) {
//
// This entry corresponds to the bus that
// we care about.
//
return TRUE;
}
}
ExtTable = (PMPS_EXTENTRY) (((PUCHAR) ExtTable) + ExtTable->Length);
}
//
// Compaq machines have their own special ways to be busted. So,
// when dealing with Compaq, never believe their MP table at all.
// Go straight to probing the hardware.
//
if (!strstr(PcMpTablePtr->OemId, "COMPAQ")) {
//
// If this is not Compaq, assume that probing the hardware
// is not yet necessary.
//
if (biosContainsAddressInfo) {
//
// Some bus in this machine contained address
// info, but ours didn't.
//
return FALSE;
}
//
// We can't figure out much from the MPS tables.
//
status = HalpPci2MpsBusNumber(MpsBus,
&childPci);
//
// This wasn't a PCI bus. Guess that it is a root.
//
if (!NT_SUCCESS(status)) {
return TRUE;
}
}
}
//
// This is a PCI bus, so scan the other PCI busses looking
// for it's parent.
//
childPci = MpsBus;
parentPci = childPci - 1;
while (TRUE) {
//
// Find the bridge.
//
bridgeSlot.u.AsULONG = 0;
for (d = 0; d < PCI_MAX_DEVICES; d++) {
for (f = 0; f < PCI_MAX_FUNCTION; f++) {
bridgeSlot.u.bits.DeviceNumber = d;
bridgeSlot.u.bits.FunctionNumber = f;
bytesRead = HalGetBusDataByOffset(PCIConfiguration,
parentPci,
bridgeSlot.u.AsULONG,
&pciData,
0,
BRIDGE_HEADER_BUFFER_SIZE);
if (bytesRead == (ULONG)BRIDGE_HEADER_BUFFER_SIZE) {
if ((pciData.VendorID != PCI_INVALID_VENDORID) &&
(PCI_CONFIGURATION_TYPE((&pciData)) != PCI_DEVICE_TYPE)) {
//
// This is a bridge of some sort.
//
if (pciData.u.type1.SecondaryBus == childPci) {
//
// It is also the bridge that creates the
// PCI bus. Thus this isn't a root.
return FALSE;
}
}
}
}
}
//
// No bridge found. Must be a root.
//
if (parentPci == 0) {
return TRUE;
}
parentPci--;
}
}