[edk2-staging/UEFI_PCI_ENHANCE-2 PATCH 10/15] MdeModulePkg/PciBusDxe: Enable NoSnoop feature

["Javeed, Ashraf" <ashraf.javeed@intel.com>]

REF:
  https://bugzilla.tianocore.org/show_bug.cgi?id=1954
  https://bugzilla.tianocore.org/show_bug.cgi?id=2194
  https://bugzilla.tianocore.org/show_bug.cgi?id=2313
  https://bugzilla.tianocore.org/show_bug.cgi?id=2499
  https://bugzilla.tianocore.org/show_bug.cgi?id=2500

Add the Program phase feature init routine for NoSnoop
PCIe feature.

Signed-off-by: Ashraf Javeed <ashraf.javeed@intel.com>
Signed-off-by: Ray Ni <ray.ni@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Ashraf Javeed <ashraf.javeed@intel.com>
---
 MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatureSupport.c |  4 ++++
 MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatures.c       | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatures.h       |  7 +++++++
 3 files changed, 62 insertions(+)

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatureSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatureSupport.c
index 9948e17..6bf06b0 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatureSupport.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatureSupport.c
@@ -58,6 +58,8 @@ PCIE_FEATURE_ENTRY  mPcieFeatures[] = {
               TRUE, { TRUE,  TRUE }, { NULL,                    MaxReadRequestSizeProgram } },
   { OFFSET_OF (EFI_PCI_EXPRESS_PLATFORM_POLICY, RelaxedOrdering),
               TRUE, { TRUE,  TRUE }, { NULL,                    RelaxedOrderingProgram } },
+  { OFFSET_OF (EFI_PCI_EXPRESS_PLATFORM_POLICY, NoSnoop),
+              TRUE, { TRUE,  TRUE }, { NULL,                    NoSnoopProgram } },
 };
 
 /**
@@ -233,6 +235,8 @@ PcieNotifyDeviceState (
   PcieDeviceState.MaxPayloadSize      = (UINT8)PciIoDevice->PciExpressCapability.DeviceControl.Bits.MaxPayloadSize;
   PcieDeviceState.MaxReadRequestSize  = (UINT8)PciIoDevice->PciExpressCapability.DeviceControl.Bits.MaxReadRequestSize;
   PcieDeviceState.RelaxedOrdering     = (UINT8)PciIoDevice->PciExpressCapability.DeviceControl.Bits.RelaxedOrdering;
+  PcieDeviceState.NoSnoop             = (UINT8)PciIoDevice->PciExpressCapability.DeviceControl.Bits.NoSnoop;
+
   return mPciePlatformProtocol->NotifyDeviceState (
                                   mPciePlatformProtocol,
                                   PciIoDevice->Handle,
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatures.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatures.c
index 5216dac..6c22feb 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatures.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatures.c
@@ -216,3 +216,54 @@ RelaxedOrderingProgram (
   return EFI_SUCCESS;
 }
 
+/**
+  Overrides the PCI Device Control register No-Snoop register field; if
+  the hardware value is different than the intended value.
+
+  @param PciDevice              A pointer to the PCI_IO_DEVICE instance.
+  @param Level                  The level of the PCI device in the heirarchy.
+                                Level of root ports is 0.
+  @param Context                Pointer to feature specific context.
+
+  @retval EFI_SUCCESS           The data was read from or written to the PCI device.
+  @retval EFI_UNSUPPORTED       The address range specified by Offset, Width, and Count is not
+                                valid for the PCI configuration header of the PCI controller.
+  @retval EFI_INVALID_PARAMETER Buffer is NULL or Width is invalid.
+
+**/
+EFI_STATUS
+NoSnoopProgram (
+  IN PCI_IO_DEVICE *PciDevice,
+  IN UINTN         Level,
+  IN VOID          **Context
+  )
+{
+  ASSERT (*Context == NULL);
+
+  if (PciDevice->DeviceState.NoSnoop == EFI_PCI_EXPRESS_DEVICE_POLICY_NOT_APPLICABLE ||
+      PciDevice->DeviceState.NoSnoop == EFI_PCI_EXPRESS_DEVICE_POLICY_AUTO) {
+    return EFI_SUCCESS;
+  }
+
+
+  if (PciDevice->PciExpressCapability.DeviceControl.Bits.NoSnoop != PciDevice->DeviceState.NoSnoop) {
+    DEBUG ((
+      DEBUG_INFO, "  %a [%02d|%02d|%02d]: %x -> %x\n",
+      __FUNCTION__, PciDevice->BusNumber, PciDevice->DeviceNumber, PciDevice->FunctionNumber,
+      PciDevice->PciExpressCapability.DeviceControl.Bits.NoSnoop,
+      PciDevice->DeviceState.NoSnoop
+      ));
+    PciDevice->PciExpressCapability.DeviceControl.Bits.NoSnoop = PciDevice->DeviceState.NoSnoop;
+
+    return PciDevice->PciIo.Pci.Write (
+                                  &PciDevice->PciIo,
+                                  EfiPciIoWidthUint16,
+                                  PciDevice->PciExpressCapabilityOffset
+                                  + OFFSET_OF (PCI_CAPABILITY_PCIEXP, DeviceControl),
+                                  1,
+                                  &PciDevice->PciExpressCapability.DeviceControl.Uint16
+                                  );
+  }
+  return EFI_SUCCESS;
+}
+
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatures.h b/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatures.h
index 7d70f06..60b8742 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatures.h
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PcieFeatures.h
@@ -38,4 +38,11 @@ RelaxedOrderingProgram (
   IN VOID          **Context
   );
 
+EFI_STATUS
+NoSnoopProgram (
+  IN PCI_IO_DEVICE *PciDevice,
+  IN UINTN         Level,
+  IN VOID          **Context
+  );
+
 #endif
-- 
2.21.0.windows.1