MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c | 39 ++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-)
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>
Cc: Star Zeng <star.zeng@intel.com>
---
MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c | 39 ++++++++++++++++++++++++++++++++-
1 file changed, 38 insertions(+), 1 deletion(-)
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c
index 976496379a..729e86b55e 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c
@@ -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;
+ //
+ // Get next available 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,
--
2.16.1.windows.1
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The code comment "// Get next available PCI bus number" comes from PciAllocateBusNumber? It should be updated accordingly for PciGetMaxBusNumber, right? With the comment updated, Reviewed-by: Star Zeng <star.zeng@intel.com>. Thanks, Star -----Original Message----- From: Ni, Ruiyu Sent: Wednesday, May 23, 2018 11:30 AM To: edk2-devel@lists.01.org Cc: Zeng, Star <star.zeng@intel.com> Subject: [PATCH] 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> Cc: Star Zeng <star.zeng@intel.com> --- MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c | 39 ++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-) diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c index 976496379a..729e86b55e 100644 --- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c +++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciLib.c @@ -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; + // + // Get next available 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, -- 2.16.1.windows.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
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