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MdeModulePkg/PciBus: Use actual max bus # for subordinary bus # 

Current code assumes the max bus(0xFF) is under this P2P bridge and
temporarily set it as subordinate bus.
It may cause silicon hangs during PCI enumeration in some specific
case.

Instead, it should get the max bus number from the bus number
resources returned from
PCI_HOST_BRIDGE_RESOURCE_ALLOCATION.StartBusEnumeration() and set it
as subordinate bus.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
This commit is contained in:
Ruiyu Ni 2018-05-23 11:28:46 +08:00
parent 7dc7c7435e
commit 03ac238b1f
1 changed files with 38 additions and 1 deletions
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39
MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c
View File

@ -29,6 +29,43 @@ CHAR16 *mBarTypeStr[] = {
L"Unknow"
};
/**
Retrieve the max bus number that is assigned to the Root Bridge hierarchy.
It can support the case that there are multiple bus ranges.
@param Bridge Bridge device instance.
@retval The max bus number that is assigned to this Root Bridge hierarchy.
**/
UINT16
PciGetMaxBusNumber (
IN PCI_IO_DEVICE *Bridge
)
{
PCI_IO_DEVICE *RootBridge;
EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *BusNumberRanges;
UINT64 MaxNumberInRange;
//
// Get PCI Root Bridge device
//
RootBridge = Bridge;
while (RootBridge->Parent != NULL) {
RootBridge = RootBridge->Parent;
}
MaxNumberInRange = 0;
//
// Iterate the bus number ranges to get max PCI bus number
//
BusNumberRanges = RootBridge->BusNumberRanges;
while (BusNumberRanges->Desc != ACPI_END_TAG_DESCRIPTOR) {
MaxNumberInRange = BusNumberRanges->AddrRangeMin + BusNumberRanges->AddrLen - 1;
BusNumberRanges++;
}
return (UINT16) MaxNumberInRange;
}
/**
Retrieve the PCI Card device BAR information via PciIo interface.
@ -1193,7 +1230,7 @@ PciScanBus (
// Temporarily initialize SubBusNumber to maximum bus number to ensure the
// PCI configuration transaction to go through any PPB
//
Register = 0xFF;
Register = PciGetMaxBusNumber (Bridge);
Address = EFI_PCI_ADDRESS (StartBusNumber, Device, Func, PCI_BRIDGE_SUBORDINATE_BUS_REGISTER_OFFSET);
Status = PciRootBridgeIo->Pci.Write (
PciRootBridgeIo,