[edk2-staging/UEFI_PCI_ENHANCE-2 PATCH 12/12] PciBusDxe: New PCI feature Completion Timeout

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

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2313

The code changes are made; as per the PCI Base Specification 4 Revision
1; to enable the configuration of new PCI feature Completion Timeout
(CTO), which enables the PCI function to wait on programmed duration for
its transactions before timeout, or disable its detection mechanism.

The code changes are made to configure only those PCI devices which are
requested to override by platform through the new PCI Platform protocol
interface for device-specific policies. The changes are made to also com-
ply with the device-specific capability attributes.

The code follows the below implementation specific rules in case the req-
uested platform policy does not match with the device-specific capability
attributes:-
(1) if device is capable of Range A only and if platform ask for any of
    ranges B, C, D; than this implementation will only program the default
    range value for the duration of 50us to 50ms
(2) if device is capable of Range B, or range B & C, or Ranges B, C & D
    only and if the platform ask for the Range A; than this implementation
    will only program the default range value for the duration of 50us to
    50ms
(3) if the device is capable of Range B only, or the ranges A & B; and if
    the platform ask for Range C, or Range D values, than this implement-
    ation will only program the Range B value for the duration of 65ms to
    210ms
(4) if the device is capable of Ranges B & C, or Ranges A, B, and C; and
    if the platform ask for Range D values; than this implementation will
    only program the Range C for the duration of 1s to 3.5s


Signed-off-by: Ashraf Javeed <ashraf.javeed@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>
---
 MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h             |   1 +
 MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.c  | 413 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.c |  84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 498 insertions(+)

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h
index be1c341..b6ec14f 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h
@@ -294,6 +294,7 @@ struct _PCI_IO_DEVICE {
   UINT8                                     SetupMRRS;
   PCI_FEATURE_POLICY                        SetupRO;
   PCI_FEATURE_POLICY                        SetupNS;
+  PCI_FEATURE_POLICY                        SetupCTO;
 };
 
 #define PCI_IO_DEVICE_FROM_PCI_IO_THIS(a) \
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.c
index a7f0a2f..ba0de0d 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.c
@@ -765,6 +765,294 @@ ProcessMaxReadReqSize (
   return EFI_SUCCESS;
 }
 
+/**
+  To determine the CTO Range A values
+
+  @param  CtoValue    input CTO range value from 0 to 14
+  @retval TRUE        the given CTO value belongs to Range A
+          FALSE       the given value does not belong to Range A
+**/
+BOOLEAN
+IsCtoRangeA (
+  IN  UINT8   CtoValue
+  )
+{
+  switch (CtoValue) {
+    case  PCIE_COMPLETION_TIMEOUT_50US_100US:
+    case  PCIE_COMPLETION_TIMEOUT_1MS_10MS:
+      return TRUE;
+  }
+  return FALSE;
+}
+
+/**
+  To determine the CTO Range B values
+
+  @param  CtoValue    input CTO range value from 0 to 14
+  @retval TRUE        the given CTO value belongs to Range B
+          FALSE       the given value does not belong to Range B
+**/
+BOOLEAN
+IsCtoRangeB (
+  IN  UINT8   CtoValue
+  )
+{
+  switch (CtoValue) {
+    case  PCIE_COMPLETION_TIMEOUT_16MS_55MS:
+    case  PCIE_COMPLETION_TIMEOUT_65MS_210MS:
+      return TRUE;
+  }
+  return FALSE;
+}
+
+/**
+  To determine the CTO Range C values
+
+  @param  CtoValue    input CTO range value from 0 to 14
+  @retval TRUE        the given CTO value belongs to Range C
+          FALSE       the given value does not belong to Range C
+**/
+BOOLEAN
+IsCtoRangeC (
+  IN  UINT8   CtoValue
+  )
+{
+  switch (CtoValue) {
+    case  PCIE_COMPLETION_TIMEOUT_260MS_900MS:
+    case  PCIE_COMPLETION_TIMEOUT_1S_3_5S:
+      return TRUE;
+  }
+  return FALSE;
+}
+
+/**
+  To determine the CTO Range D values
+
+  @param  CtoValue    input CTO range value from 0 to 14
+  @retval TRUE        the given CTO value belongs to Range D
+          FALSE       the given value does not belong to Range D
+**/
+BOOLEAN
+IsCtoRangeD (
+  IN  UINT8   CtoValue
+  )
+{
+  switch (CtoValue) {
+    case  PCIE_COMPLETION_TIMEOUT_4S_13S:
+    case  PCIE_COMPLETION_TIMEOUT_17S_64S:
+      return TRUE;
+  }
+  return FALSE;
+}
+
+/**
+  The main routine which process the PCI feature Completion Timeout as per the
+  device-specific platform policy, as well as in complaince with the PCI Base
+  specification Revision 4.
+
+  @param PciDevice                      A pointer to the PCI_IO_DEVICE.
+  @param PciConfigPhase                 for the PCI feature configuration phases:
+                                        PciFeatureGetDevicePolicy & PciFeatureSetupPhase
+
+  @retval EFI_SUCCESS                   processing of PCI feature CTO is successful.
+**/
+EFI_STATUS
+ProcessCompletionTimeout (
+  IN  PCI_IO_DEVICE                           *PciDevice,
+  IN  PCI_FEATURE_CONFIGURATION_PHASE         PciConfigPhase
+  )
+{
+  PCI_REG_PCIE_DEVICE_CAPABILITY2 DeviceCap2;
+  UINT8                           CtoRangeValue;
+
+  if (PciConfigPhase != PciFeatureGetDevicePolicy) {
+    //
+    // no reprocessing required for device CTO configuration
+    //
+    return  EFI_SUCCESS;
+  }
+
+  if (!PciDevice->SetupCTO.Override) {
+    //
+    // No override of CTO is required for this device
+    //
+    return  EFI_SUCCESS;
+  }
+
+  //
+  // determine the CTO range values as per its device capability register
+  //
+  DeviceCap2.Uint32 = PciDevice->PciExpStruct.DeviceCapability2.Uint32;
+  if (!DeviceCap2.Bits.CompletionTimeoutRanges
+      && !DeviceCap2.Bits.CompletionTimeoutDisable
+  ) {
+    //
+    // device does not support the CTO mechanism, hence no override is applicable
+    //
+    return EFI_SUCCESS;
+  }
+
+  //
+  // override the device CTO values if applicable
+  //
+  if (PciDevice->SetupCTO.Act) {
+    //
+    // program the CTO range values
+    //
+    if (DeviceCap2.Bits.CompletionTimeoutRanges) {
+      CtoRangeValue = PCIE_COMPLETION_TIMEOUT_50US_50MS;
+      //
+      // in case if the supported CTO range and the requirement from platform
+      // policy does not match, than the CTO range setting would be based on
+      // this driver's implementation specific, and its rules are as follows:-
+      //
+      // if device is capable of Range A only and if platform ask for any of
+      // ranges B, C, D; than this implementation will only program the default
+      // range value for the duration of 50us to 50ms.
+      //
+      // if device is capable of Range B, or range B & C, or Ranges B, C & D only
+      // and if the platform ask for the Range A; than this implementation will
+      // only program the default range value for the duration of 50us to 50ms.
+      //
+      // if the device is capable of Range B only, or the ranges A & B; and the
+      // platform ask for Range C, or Range D values, than this implementation
+      // will only program the Range B value for the duration of 65ms to 210ms.
+      //
+      // if the device is capable of Ranges B & C, or Ranges A, B, and C; and
+      // if the platform ask for Range D values; than this implementation will
+      // only program the Range C for the duration of 1s to 3.5s.
+      //
+
+      switch (DeviceCap2.Bits.CompletionTimeoutRanges) {
+        case  PCIE_COMPLETION_TIMEOUT_RANGE_A_SUPPORTED:
+          if (IsCtoRangeA (PciDevice->SetupCTO.Support)) {
+            CtoRangeValue = PciDevice->SetupCTO.Support;
+          }
+          //
+          // if device is capable of Range A only and if platform ask for any of
+          // ranges B, C, D; than this implementation will only program the default
+          // range value for the duration of 50us to 50ms.
+          //
+          if (IsCtoRangeB (PciDevice->SetupCTO.Support)
+              || IsCtoRangeC (PciDevice->SetupCTO.Support)
+              || IsCtoRangeD (PciDevice->SetupCTO.Support)
+          ) {
+            CtoRangeValue = PCIE_COMPLETION_TIMEOUT_50US_50MS;
+          }
+          break;
+
+        case  PCIE_COMPLETION_TIMEOUT_RANGE_B_SUPPORTED:
+          //
+          // if device is capable of Range B, or range B & C, or Ranges B, C & D only
+          // and if the platform ask for the Range A; than this implementation will
+          // only program the default range value for the duration of 50us to 50ms.
+          //
+          if (IsCtoRangeA (PciDevice->SetupCTO.Support)) {
+            CtoRangeValue = PCIE_COMPLETION_TIMEOUT_50US_50MS;
+          }
+
+          if (IsCtoRangeB (PciDevice->SetupCTO.Support)) {
+            CtoRangeValue = PciDevice->SetupCTO.Support;
+          }
+          //
+          // if the device is capable of Range B only, or the ranges A & B; and the
+          // platform ask for Range C, or Range D values, than this implementation
+          // will only program the Range B value for the duration of 65ms to 210ms.
+          //
+          if (IsCtoRangeC (PciDevice->SetupCTO.Support)
+              || IsCtoRangeD (PciDevice->SetupCTO.Support)
+          ) {
+            CtoRangeValue = PCIE_COMPLETION_TIMEOUT_65MS_210MS;
+          }
+          break;
+
+        case  PCIE_COMPLETION_TIMEOUT_RANGE_B_C_SUPPORTED:
+          if (IsCtoRangeA (PciDevice->SetupCTO.Support)) {
+            CtoRangeValue = PCIE_COMPLETION_TIMEOUT_50US_50MS;
+          }
+
+          if (IsCtoRangeB (PciDevice->SetupCTO.Support)
+              || IsCtoRangeC (PciDevice->SetupCTO.Support)
+              ) {
+            CtoRangeValue = PciDevice->SetupCTO.Support;
+          }
+          //
+          // if the device is capable of Ranges B & C, or Ranges A, B, and C; and
+          // if the platform ask for Range D values; than this implementation will
+          // only program the Range C for the duration of 1s to 3.5s.
+          //
+          if (IsCtoRangeD (PciDevice->SetupCTO.Support)) {
+            CtoRangeValue = PCIE_COMPLETION_TIMEOUT_1S_3_5S;
+          }
+          break;
+
+        case  PCIE_COMPLETION_TIMEOUT_RANGE_B_C_D_SUPPORTED:
+          if (IsCtoRangeA (PciDevice->SetupCTO.Support)) {
+            CtoRangeValue = PCIE_COMPLETION_TIMEOUT_50US_50MS;
+          }
+          if (IsCtoRangeB (PciDevice->SetupCTO.Support)
+              || IsCtoRangeC (PciDevice->SetupCTO.Support)
+              || IsCtoRangeD (PciDevice->SetupCTO.Support)
+          ) {
+            CtoRangeValue = PciDevice->SetupCTO.Support;
+          }
+          break;
+
+        case  PCIE_COMPLETION_TIMEOUT_RANGE_A_B_SUPPORTED:
+          if (IsCtoRangeA (PciDevice->SetupCTO.Support)
+              || IsCtoRangeB (PciDevice->SetupCTO.Support)
+              ) {
+            CtoRangeValue = PciDevice->SetupCTO.Support;
+          }
+          if (IsCtoRangeC (PciDevice->SetupCTO.Support)
+              || IsCtoRangeD (PciDevice->SetupCTO.Support)
+          ) {
+            CtoRangeValue = PCIE_COMPLETION_TIMEOUT_65MS_210MS;
+          }
+          break;
+
+        case  PCIE_COMPLETION_TIMEOUT_RANGE_A_B_C_SUPPORTED:
+          if (IsCtoRangeA (PciDevice->SetupCTO.Support)
+              || IsCtoRangeB (PciDevice->SetupCTO.Support)
+              || IsCtoRangeC (PciDevice->SetupCTO.Support)
+          ) {
+            CtoRangeValue = PciDevice->SetupCTO.Support;
+          }
+          if (IsCtoRangeD (PciDevice->SetupCTO.Support)) {
+            CtoRangeValue = PCIE_COMPLETION_TIMEOUT_1S_3_5S;
+          }
+          break;
+
+        case  PCIE_COMPLETION_TIMEOUT_RANGE_A_B_C_D_SUPPORTED:
+          if (IsCtoRangeA (PciDevice->SetupCTO.Support)
+              || IsCtoRangeB (PciDevice->SetupCTO.Support)
+              || IsCtoRangeC (PciDevice->SetupCTO.Support)
+              || IsCtoRangeD (PciDevice->SetupCTO.Support)
+          ) {
+            CtoRangeValue = PciDevice->SetupCTO.Support;
+          }
+          break;
+
+        default:
+          DEBUG ((
+              DEBUG_ERROR, "Invalid CTO range: %d\n",
+              DeviceCap2.Bits.CompletionTimeoutRanges
+          ));
+          return EFI_INVALID_PARAMETER;
+      }
+
+      if (PciDevice->SetupCTO.Support != CtoRangeValue) {
+        PciDevice->SetupCTO.Support = CtoRangeValue;
+      }
+    }
+    DEBUG (( DEBUG_INFO, "CTO enable: %d, CTO range: 0x%x,",
+        PciDevice->SetupCTO.Act,
+        PciDevice->SetupCTO.Support
+    ));
+  }
+  return EFI_SUCCESS;
+}
+
 /**
   Overrides the PCI Device Control register MaxPayloadSize register field; if
   the hardware value is different than the intended value.
@@ -1061,6 +1349,119 @@ OverrideNoSnoop (
   return Status;
 }
 
+/**
+  Overrides the PCI Device Control2 register Completion Timeout range; if
+  the hardware value is different than the intended value.
+
+  @param  PciDevice             A pointer to the PCI_IO_DEVICE instance.
+
+  @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
+OverrideCompletionTimeout (
+  IN PCI_IO_DEVICE          *PciDevice
+  )
+{
+  PCI_REG_PCIE_DEVICE_CONTROL2    DeviceCtl2;
+  PCI_REG_PCIE_DEVICE_CAPABILITY2 DeviceCap2;
+  UINT32                          Offset;
+  EFI_STATUS                      Status;
+  EFI_TPL                         OldTpl;
+
+  if (!PciDevice->SetupCTO.Override) {
+    //
+    // No override of CTO is required for this device
+    //
+    DEBUG (( DEBUG_INFO, "CTO skipped,"));
+    return  EFI_SUCCESS;
+  }
+
+  //
+  // to program the CTO range values, determine in its device capability register
+  //
+  DeviceCap2.Uint32 = PciDevice->PciExpStruct.DeviceCapability2.Uint32;
+  if (DeviceCap2.Bits.CompletionTimeoutRanges
+      || DeviceCap2.Bits.CompletionTimeoutDisable) {
+    //
+    // device supports the CTO mechanism
+    //
+    DeviceCtl2.Uint16 = 0;
+    Offset = PciDevice->PciExpressCapabilityOffset +
+              OFFSET_OF (PCI_CAPABILITY_PCIEXP, DeviceControl2);
+    Status = PciDevice->PciIo.Pci.Read (
+                                  &PciDevice->PciIo,
+                                  EfiPciIoWidthUint16,
+                                  Offset,
+                                  1,
+                                  &DeviceCtl2.Uint16
+                                  );
+    if (EFI_ERROR(Status)){
+      DEBUG (( DEBUG_ERROR, "Unexpected DeviceControl2 register (0x%x) read error!",
+                Offset
+      ));
+      return Status;
+    }
+  } else {
+    //
+    // device does not support the CTO mechanism, hence no override performed
+    //
+    DEBUG (( DEBUG_INFO, "CTO n/a,"));
+    return EFI_SUCCESS;
+  }
+
+  //
+  // override the device CTO values if applicable
+  //
+  if (PciDevice->SetupCTO.Act) {
+    //
+    // program the CTO range values
+    //
+    if (PciDevice->SetupCTO.Support != DeviceCtl2.Bits.CompletionTimeoutValue) {
+      DeviceCtl2.Bits.CompletionTimeoutValue = PciDevice->SetupCTO.Support;
+    }
+  } else {
+    //
+    // disable the CTO mechanism in device
+    //
+    DeviceCtl2.Bits.CompletionTimeoutValue = 0;
+    DeviceCtl2.Bits.CompletionTimeoutDisable = 1;
+  }
+  DEBUG (( DEBUG_INFO, "CTO disable: %d, CTO range: 0x%x,",
+      DeviceCtl2.Bits.CompletionTimeoutDisable,
+      DeviceCtl2.Bits.CompletionTimeoutValue
+  ));
+
+  //
+  // Raise TPL to high level to disable timer interrupt while the write operation completes
+  //
+  OldTpl = gBS->RaiseTPL (TPL_HIGH_LEVEL);
+
+  Status = PciDevice->PciIo.Pci.Write (
+                                &PciDevice->PciIo,
+                                EfiPciIoWidthUint16,
+                                Offset,
+                                1,
+                                &DeviceCtl2.Uint16
+                                );
+  //
+  // Restore TPL to its original level
+  //
+  gBS->RestoreTPL (OldTpl);
+
+  if (!EFI_ERROR(Status)) {
+    PciDevice->PciExpStruct.DeviceControl2.Uint16 = DeviceCtl2.Uint16;
+  } else {
+    DEBUG (( DEBUG_ERROR, "Unexpected DeviceControl2 register (0x%x) write error!",
+        Offset
+    ));
+  }
+  return Status;
+}
+
 /**
   helper routine to dump the PCIe Device Port Type
 **/
@@ -1169,6 +1570,15 @@ SetupDevicePciFeatures (
               OtherPciFeaturesConfigTable
               );
   }
+  //
+  // process the PCI device CTO range values to be configured
+  //
+  if (SetupCompletionTimeout ()) {
+    Status = ProcessCompletionTimeout (
+              PciDevice,
+              PciConfigPhase
+              );
+  }
   DEBUG ((DEBUG_INFO, "]\n"));
   return Status;
 }
@@ -1278,6 +1688,9 @@ ProgramDevicePciFeatures (
   if (SetupNoSnoop ()) {
     Status = OverrideNoSnoop (PciDevice);
   }
+  if (SetupCompletionTimeout()) {
+    Status = OverrideCompletionTimeout (PciDevice);
+  }
   DEBUG (( DEBUG_INFO, "\n"));
   return Status;
 }
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.c
index 47295cd..7ee0d7d 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.c
@@ -549,6 +549,85 @@ SetDevicePolicyNoSnoop (
   }
 }
 
+/**
+  Routine to set the device-specific policy for the PCI feature CTO value range
+  or disable
+
+  @param  CtoSupport    value corresponding to data type EFI_PCI_CONF_CTO_SUPPORT
+  @param  PciDevice     A pointer to PCI_IO_DEVICE
+**/
+VOID
+SetDevicePolicyCTO (
+  IN  EFI_PCI_CONF_CTO_SUPPORT    CtoSupport,
+  OUT PCI_IO_DEVICE               *PciDevice
+)
+{
+  //
+  // implementation specific rules for the usage of PCI_FEATURE_POLICY members
+  // exclusively for the PCI Feature CTO
+  //
+  // .Override = 0 to skip this PCI feature CTO for the PCI device
+  // .Override = 1 to program this CTO PCI feature
+  //      .Act = 1 to program the CTO range as per given device policy in .Support
+  //      .Act = 0 to disable the CTO mechanism in the PCI device, CTO set to default range
+  //
+  switch (CtoSupport) {
+    case  EFI_PCI_CONF_CTO_AUTO:
+      PciDevice->SetupCTO.Override = 0;
+      break;
+    case  EFI_PCI_CONF_CTO_DEFAULT:
+      PciDevice->SetupCTO.Override = 1;
+      PciDevice->SetupCTO.Act = 1;
+      PciDevice->SetupCTO.Support = PCIE_COMPLETION_TIMEOUT_50US_50MS;
+      break;
+    case  EFI_PCI_CONF_CTO_RANGE_A1:
+      PciDevice->SetupCTO.Override = 1;
+      PciDevice->SetupCTO.Act = 1;
+      PciDevice->SetupCTO.Support = PCIE_COMPLETION_TIMEOUT_50US_100US;
+      break;
+    case  EFI_PCI_CONF_CTO_RANGE_A2:
+      PciDevice->SetupCTO.Override = 1;
+      PciDevice->SetupCTO.Act = 1;
+      PciDevice->SetupCTO.Support = PCIE_COMPLETION_TIMEOUT_1MS_10MS;
+      break;
+    case  EFI_PCI_CONF_CTO_RANGE_B1:
+      PciDevice->SetupCTO.Override = 1;
+      PciDevice->SetupCTO.Act = 1;
+      PciDevice->SetupCTO.Support = PCIE_COMPLETION_TIMEOUT_16MS_55MS;
+      break;
+    case  EFI_PCI_CONF_CTO_RANGE_B2:
+      PciDevice->SetupCTO.Override = 1;
+      PciDevice->SetupCTO.Act = 1;
+      PciDevice->SetupCTO.Support = PCIE_COMPLETION_TIMEOUT_65MS_210MS;
+      break;
+    case  EFI_PCI_CONF_CTO_RANGE_C1:
+      PciDevice->SetupCTO.Override = 1;
+      PciDevice->SetupCTO.Act = 1;
+      PciDevice->SetupCTO.Support = PCIE_COMPLETION_TIMEOUT_260MS_900MS;
+      break;
+    case  EFI_PCI_CONF_CTO_RANGE_C2:
+      PciDevice->SetupCTO.Override = 1;
+      PciDevice->SetupCTO.Act = 1;
+      PciDevice->SetupCTO.Support = PCIE_COMPLETION_TIMEOUT_1S_3_5S;
+      break;
+    case  EFI_PCI_CONF_CTO_RANGE_D1:
+      PciDevice->SetupCTO.Override = 1;
+      PciDevice->SetupCTO.Act = 1;
+      PciDevice->SetupCTO.Support = PCIE_COMPLETION_TIMEOUT_4S_13S;
+      break;
+    case  EFI_PCI_CONF_CTO_RANGE_D2:
+      PciDevice->SetupCTO.Override = 1;
+      PciDevice->SetupCTO.Act = 1;
+      PciDevice->SetupCTO.Support = PCIE_COMPLETION_TIMEOUT_17S_64S;
+      break;
+    case  EFI_PCI_CONF_CTO_DET_DISABLE:
+      PciDevice->SetupCTO.Override = 1;
+      PciDevice->SetupCTO.Act = 0;
+      PciDevice->SetupCTO.Support = PCIE_COMPLETION_TIMEOUT_50US_50MS;
+      break;
+  }
+}
+
 /**
   Generic routine to setup the PCI features as per its predetermined defaults.
 **/
@@ -561,6 +640,7 @@ SetupDefaultsDevicePlatformPolicy (
   PciDevice->SetupMRRS = EFI_PCI_CONF_MAX_READ_REQ_SIZE_AUTO;
   PciDevice->SetupRO.Override = 0;
   PciDevice->SetupNS.Override = 0;
+  PciDevice->SetupCTO.Override = 0;
 }
 
 /**
@@ -606,6 +686,10 @@ GetPciDevicePlatformPolicyEx (
       // set the device specific policy for No-Snoop
       //
       SetDevicePolicyNoSnoop (PciPlatformExtendedPolicy.DeviceCtlNoSnoop, PciIoDevice);
+      //
+      // set the device specific policy for Completion Timeout (CTO)
+      //
+      SetDevicePolicyCTO (PciPlatformExtendedPolicy.CTOsupport, PciIoDevice);
 
       DEBUG ((
           DEBUG_INFO, "[device policy: platform]"
-- 
2.21.0.windows.1