diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciHotPlugSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciHotPlugSupport.c index ca8766869a..73bcd32788 100644 --- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciHotPlugSupport.c +++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciHotPlugSupport.c @@ -316,6 +316,94 @@ IsSHPC ( return FALSE; } +/** + Check whether PciIoDevice supports PCIe hotplug. + + This is equivalent to the following condition: + - the device is either a PCIe switch downstream port or a root port, + - and the device has the SlotImplemented bit set in its PCIe capability + register, + - and the device has the HotPlugCapable bit set in its slot capabilities + register. + + @param[in] PciIoDevice The device being checked. + + @retval TRUE PciIoDevice is a PCIe port that accepts a hotplugged device. + @retval FALSE Otherwise. + +**/ +BOOLEAN +SupportsPcieHotplug ( + IN PCI_IO_DEVICE *PciIoDevice + ) +{ + UINT32 Offset; + EFI_STATUS Status; + PCI_REG_PCIE_CAPABILITY Capability; + PCI_REG_PCIE_SLOT_CAPABILITY SlotCapability; + + if (PciIoDevice == NULL) { + return FALSE; + } + + // + // Read the PCI Express Capabilities Register + // + if (!PciIoDevice->IsPciExp) { + return FALSE; + } + Offset = PciIoDevice->PciExpressCapabilityOffset + + OFFSET_OF (PCI_CAPABILITY_PCIEXP, Capability); + Status = PciIoDevice->PciIo.Pci.Read ( + &PciIoDevice->PciIo, + EfiPciIoWidthUint16, + Offset, + 1, + &Capability + ); + if (EFI_ERROR (Status)) { + return FALSE; + } + + // + // Check the contents of the register + // + switch (Capability.Bits.DevicePortType) { + case PCIE_DEVICE_PORT_TYPE_ROOT_PORT: + case PCIE_DEVICE_PORT_TYPE_DOWNSTREAM_PORT: + break; + default: + return FALSE; + } + if (!Capability.Bits.SlotImplemented) { + return FALSE; + } + + // + // Read the Slot Capabilities Register + // + Offset = PciIoDevice->PciExpressCapabilityOffset + + OFFSET_OF (PCI_CAPABILITY_PCIEXP, SlotCapability); + Status = PciIoDevice->PciIo.Pci.Read ( + &PciIoDevice->PciIo, + EfiPciIoWidthUint32, + Offset, + 1, + &SlotCapability + ); + if (EFI_ERROR (Status)) { + return FALSE; + } + + // + // Check the contents of the register + // + if (SlotCapability.Bits.HotPlugCapable) { + return TRUE; + } + return FALSE; +} + /** Get resource padding if the specified PCI bridge is a hot plug bus. @@ -382,6 +470,14 @@ IsPciHotPlugBus ( return TRUE; } + if (SupportsPcieHotplug (PciIoDevice)) { + // + // If the PPB is a PCIe root complex port or a switch downstream port, and + // implements a hot-plug capable slot, then also return TRUE. + // + return TRUE; + } + // // Otherwise, see if it is a Root HPC // diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciHotPlugSupport.h b/MdeModulePkg/Bus/Pci/PciBusDxe/PciHotPlugSupport.h index 1fb9ba9720..a285d94c93 100644 --- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciHotPlugSupport.h +++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciHotPlugSupport.h @@ -176,6 +176,27 @@ IsSHPC ( IN PCI_IO_DEVICE *PciIoDevice ); +/** + Check whether PciIoDevice supports PCIe hotplug. + + This is equivalent to the following condition: + - the device is either a PCIe switch downstream port or a root port, + - and the device has the SlotImplemented bit set in its PCIe capability + register, + - and the device has the HotPlugCapable bit set in its slot capabilities + register. + + @param[in] PciIoDevice The device being checked. + + @retval TRUE PciIoDevice is a PCIe port that accepts a hotplugged device. + @retval FALSE Otherwise. + +**/ +BOOLEAN +SupportsPcieHotplug ( + IN PCI_IO_DEVICE *PciIoDevice + ); + /** Get resource padding if the specified PCI bridge is a hot plug bus.