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MdeModulePkg/PciBusDxe: Enable Bus Master on P2P bridges on demand

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The patch dynamically enables Bus Master on P2P bridges only
when requested by a device driver through PciIo.Attribute() to enable
the Bus Master.

Signed-off-by: Sean Brogan <sean.brogan@microsoft.com>
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
This commit is contained in:
Ruiyu Ni
2017-08-16 10:26:49 -07:00
parent 265e5c82f5
commit 5db417ed25
3 changed files with 32 additions and 10 deletions
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18
MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
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@ -1218,11 +1218,12 @@ DetermineDeviceAttribute (
return Status;
}
//
// Assume the PCI Root Bridge supports DAC
// Assume the PCI Root Bridge supports DAC and Bus Master.
//
PciIoDevice->Supports |= (UINT64)(EFI_PCI_IO_ATTRIBUTE_EMBEDDED_DEVICE |
EFI_PCI_IO_ATTRIBUTE_EMBEDDED_ROM |
EFI_PCI_IO_ATTRIBUTE_DUAL_ADDRESS_CYCLE);
EFI_PCI_IO_ATTRIBUTE_DUAL_ADDRESS_CYCLE |
EFI_PCI_IO_ATTRIBUTE_BUS_MASTER);
} else {
@ -1233,9 +1234,16 @@ DetermineDeviceAttribute (
//
Command = EFI_PCI_COMMAND_IO_SPACE |
EFI_PCI_COMMAND_MEMORY_SPACE |
EFI_PCI_COMMAND_BUS_MASTER |
EFI_PCI_COMMAND_VGA_PALETTE_SNOOP;
//
// Per PCI-to-PCI Bridge Architecture all PCI-to-PCI bridges are Bus Master capable.
// So only test the Bus Master capability for PCI devices.
//
if (!IS_PCI_BRIDGE(&PciIoDevice->Pci)) {
Command |= EFI_PCI_COMMAND_BUS_MASTER;
}
BridgeControl = EFI_PCI_BRIDGE_CONTROL_ISA | EFI_PCI_BRIDGE_CONTROL_VGA | EFI_PCI_BRIDGE_CONTROL_VGA_16;
//
@ -1245,7 +1253,11 @@ DetermineDeviceAttribute (
//
// Set the supported attributes for specified PCI device
// Per PCI-to-PCI Bridge Architecture all PCI-to-PCI bridges are Bus Master capable.
//
if (IS_PCI_BRIDGE(&PciIoDevice->Pci)) {
Command |= EFI_PCI_COMMAND_BUS_MASTER;
}
PciSetDeviceAttribute (PciIoDevice, Command, BridgeControl, EFI_SET_SUPPORTS);
//