[edk2-staging/UEFI_PCI_ENHANCE-2 PATCH 08/12] PciBusDxe: New PCI feature Max_Payload_Size

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

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2194

The code changes are made to enable the configuration of new PCI feature
Max_Payload_Size (MPS), which defines the data packet size for the PCI
transactions, as per the PCI Base Specification 4 Revision 1.

The code changes are made to calibrate highest common value that is appl-
icable to all the child nodes originating from the primary parent root
port of the root bridge instance.

This programming of MPS is based on each PCI device's capability, and also
its device-specific platform policy obtained using the new PCI Platform
Protocol interface, defined in the below record:-
https://bugzilla.tianocore.org/show_bug.cgi?id=1954

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             |   4 ++++
 MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.c  | 157 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.h  |   5 +++++
 MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.c |  59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.h |  32 ++++++++++++++++++++++++++++++++
 5 files changed, 257 insertions(+)

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h
index dc29ef3..065ae54 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h
@@ -286,6 +286,10 @@ struct _PCI_IO_DEVICE {
   // This field is used to support this case.
   //
   UINT16                                    BridgeIoAlignment;
+  //
+  // Other PCI features setup flags
+  //
+  UINT8                                     SetupMPS;
 };
 
 #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 df9e696..8fdaa05 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.c
@@ -582,6 +582,146 @@ IsPciRootPortEmpty (
   return FALSE;
 }
 
+/**
+  The main routine which process the PCI feature Max_Payload_Size as per the
+  device-specific platform policy, as well as in complaince with the PCI Base
+  specification Revision 4, that aligns the value for the entire PCI heirarchy
+  starting from its physical PCI Root port / Bridge device.
+
+  @param PciDevice                      A pointer to the PCI_IO_DEVICE.
+  @param PciConfigPhase                 for the PCI feature configuration phases:
+                                        PciFeatureGetDevicePolicy & PciFeatureSetupPhase
+  @param PciFeaturesConfigurationTable  pointer to OTHER_PCI_FEATURES_CONFIGURATION_TABLE
+
+  @retval EFI_SUCCESS                   processing of PCI feature Max_Payload_Size
+                                        is successful.
+**/
+EFI_STATUS
+ProcessMaxPayloadSize (
+  IN  PCI_IO_DEVICE                           *PciDevice,
+  IN  PCI_FEATURE_CONFIGURATION_PHASE         PciConfigPhase,
+  IN  OTHER_PCI_FEATURES_CONFIGURATION_TABLE  *PciFeaturesConfigurationTable
+  )
+{
+  PCI_REG_PCIE_DEVICE_CAPABILITY          PciDeviceCap;
+  UINT8                                   MpsValue;
+
+
+  PciDeviceCap.Uint32 = PciDevice->PciExpStruct.DeviceCapability.Uint32;
+
+  if (PciConfigPhase == PciFeatureGetDevicePolicy) {
+    if (SetupMpsAsPerDeviceCapability (PciDevice->SetupMPS)) {
+      MpsValue = (UINT8)PciDeviceCap.Bits.MaxPayloadSize;
+      //
+      // no change to PCI Root ports without any endpoint device
+      //
+      if (IS_PCI_BRIDGE (&PciDevice->Pci) && PciDeviceCap.Bits.MaxPayloadSize) {
+        if (IsPciRootPortEmpty (PciDevice)) {
+          MpsValue = PCIE_MAX_PAYLOAD_SIZE_128B;
+        }
+      }
+    } else {
+      MpsValue = TranslateMpsSetupValueToPci (PciDevice->SetupMPS);
+    }
+    //
+    // discard device policy override request if greater than PCI device capability
+    //
+    PciDevice->SetupMPS = MIN ((UINT8)PciDeviceCap.Bits.MaxPayloadSize, MpsValue);
+  }
+
+  //
+  // align the MPS of the tree to the HCF with this device
+  //
+  if (PciFeaturesConfigurationTable) {
+    MpsValue = PciFeaturesConfigurationTable->Max_Payload_Size;
+
+    MpsValue = MIN (PciDevice->SetupMPS, MpsValue);
+    PciDevice->SetupMPS = MIN (PciDevice->SetupMPS, MpsValue);
+
+    if (MpsValue != PciFeaturesConfigurationTable->Max_Payload_Size) {
+      PciFeaturesConfigurationTable->Max_Payload_Size = MpsValue;
+    }
+  }
+
+  DEBUG (( DEBUG_INFO,
+      "MPS: %d [DevCap:%d],",
+      PciDevice->SetupMPS, PciDeviceCap.Bits.MaxPayloadSize
+  ));
+  return EFI_SUCCESS;
+}
+
+/**
+  Overrides the PCI Device Control register MaxPayloadSize register field; 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
+OverrideMaxPayloadSize (
+  IN PCI_IO_DEVICE          *PciDevice
+  )
+{
+  PCI_REG_PCIE_DEVICE_CONTROL PcieDev;
+  UINT32                      Offset;
+  EFI_STATUS                  Status;
+  EFI_TPL                     OldTpl;
+
+  PcieDev.Uint16 = 0;
+  Offset = PciDevice->PciExpressCapabilityOffset +
+               OFFSET_OF (PCI_CAPABILITY_PCIEXP, DeviceControl);
+  Status = PciDevice->PciIo.Pci.Read (
+                                  &PciDevice->PciIo,
+                                  EfiPciIoWidthUint16,
+                                  Offset,
+                                  1,
+                                  &PcieDev.Uint16
+                                );
+  if (EFI_ERROR(Status)){
+    DEBUG (( DEBUG_ERROR, "Unexpected DeviceControl register (0x%x) read error!",
+        Offset
+    ));
+    return Status;
+  }
+  if (PcieDev.Bits.MaxPayloadSize != PciDevice->SetupMPS) {
+    PcieDev.Bits.MaxPayloadSize = PciDevice->SetupMPS;
+    DEBUG (( DEBUG_INFO, "MPS=%d,", PciDevice->SetupMPS));
+
+    //
+    // 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,
+                                    &PcieDev.Uint16
+                                  );
+    //
+    // Restore TPL to its original level
+    //
+    gBS->RestoreTPL (OldTpl);
+
+    if (!EFI_ERROR(Status)) {
+      PciDevice->PciExpStruct.DeviceControl.Uint16 = PcieDev.Uint16;
+    } else {
+      DEBUG (( DEBUG_ERROR, "Unexpected DeviceControl register (0x%x) write error!",
+          Offset
+      ));
+    }
+  } else {
+    DEBUG (( DEBUG_INFO, "No write of MPS=%d,", PciDevice->SetupMPS));
+  }
+
+  return Status;
+}
 
 /**
   helper routine to dump the PCIe Device Port Type
@@ -669,6 +809,18 @@ SetupDevicePciFeatures (
     }
   }
 
+  DEBUG ((DEBUG_INFO, "["));
+  //
+  // process the PCI device Max_Payload_Size feature
+  //
+  if (SetupMaxPayloadSize ()) {
+    Status = ProcessMaxPayloadSize (
+              PciDevice,
+              PciConfigPhase,
+              OtherPciFeaturesConfigTable
+              );
+  }
+  DEBUG ((DEBUG_INFO, "]\n"));
   return Status;
 }
 
@@ -765,6 +917,10 @@ ProgramDevicePciFeatures (
 {
   EFI_STATUS           Status = EFI_SUCCESS;
 
+  if (SetupMaxPayloadSize ()) {
+    Status = OverrideMaxPayloadSize (PciDevice);
+  }
+  DEBUG (( DEBUG_INFO, "\n"));
   return Status;
 }
 
@@ -878,6 +1034,7 @@ AddPrimaryRootPortNode (
                     );
   if (PciConfigTable) {
     PciConfigTable->ID                          = PortNumber;
+    PciConfigTable->Max_Payload_Size            = PCIE_MAX_PAYLOAD_SIZE_4096B;
   }
   RootPortNode->OtherPciFeaturesConfigurationTable  = PciConfigTable;
 
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.h b/MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.h
index f92d008..e5ac2a3 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.h
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciFeatureSupport.h
@@ -79,6 +79,11 @@ struct _OTHER_PCI_FEATURES_CONFIGURATION_TABLE {
   // Configuration Table ID
   //
   UINTN                                     ID;
+  //
+  // to configure the PCI feature Maximum payload size to maintain the data packet
+  // size among all the PCI devices in the PCI hierarchy
+  //
+  UINT8                                     Max_Payload_Size;
 };
 
 
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.c
index 238959e..99badd6 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.c
@@ -356,6 +356,63 @@ GetPlatformPciOptionRom (
   return Status;
 }
 
+/**
+  Helper routine to indicate whether the given PCI device specific policy value
+  dictates to override the Max_Payload_Size to a particular value, or set as per
+  device capability.
+
+  @param  MPS     Input device-specific policy should be in terms of type
+                  EFI_PCI_CONF_MAX_PAYLOAD_SIZE
+
+  @retval TRUE    Setup Max_Payload_Size as per device capability
+          FALSE   override as per device-specific platform policy
+**/
+BOOLEAN
+SetupMpsAsPerDeviceCapability (
+  IN  UINT8                   MPS
+)
+{
+  if (MPS == EFI_PCI_CONF_MAX_PAYLOAD_SIZE_AUTO) {
+    return TRUE;
+  } else {
+    return FALSE;
+  }
+}
+
+/**
+  Routine to translate the given device-specific platform policy from type
+  EFI_PCI_CONF_MAX_PAYLOAD_SIZE to HW-specific value, as per PCI Base Specification
+  Revision 4.0; for the PCI feature Max_Payload_Size.
+
+  @param  MPS     Input device-specific policy should be in terms of type
+                  EFI_PCI_CONF_MAX_PAYLOAD_SIZE
+
+  @retval         Range values for the Max_Payload_Size as defined in the PCI
+                  Base Specification 4.0
+**/
+UINT8
+TranslateMpsSetupValueToPci (
+  IN  UINT8                   MPS
+)
+{
+  switch (MPS) {
+    case EFI_PCI_CONF_MAX_PAYLOAD_SIZE_128B:
+      return PCIE_MAX_PAYLOAD_SIZE_128B;
+    case EFI_PCI_CONF_MAX_PAYLOAD_SIZE_256B:
+      return PCIE_MAX_PAYLOAD_SIZE_256B;
+    case EFI_PCI_CONF_MAX_PAYLOAD_SIZE_512B:
+      return PCIE_MAX_PAYLOAD_SIZE_512B;
+    case EFI_PCI_CONF_MAX_PAYLOAD_SIZE_1024B:
+      return PCIE_MAX_PAYLOAD_SIZE_1024B;
+    case EFI_PCI_CONF_MAX_PAYLOAD_SIZE_2048B:
+      return PCIE_MAX_PAYLOAD_SIZE_2048B;
+    case EFI_PCI_CONF_MAX_PAYLOAD_SIZE_4096B:
+      return PCIE_MAX_PAYLOAD_SIZE_4096B;
+    default:
+      return PCIE_MAX_PAYLOAD_SIZE_128B;
+  }
+}
+
 /**
   Generic routine to setup the PCI features as per its predetermined defaults.
 **/
@@ -364,6 +421,7 @@ SetupDefaultsDevicePlatformPolicy (
   IN  PCI_IO_DEVICE               *PciDevice
   )
 {
+  PciDevice->SetupMPS = EFI_PCI_CONF_MAX_PAYLOAD_SIZE_AUTO;
 }
 
 /**
@@ -399,6 +457,7 @@ GetPciDevicePlatformPolicyEx (
       //
       // platform chipset policies are returned for this PCI device
       //
+      PciIoDevice->SetupMPS = PciPlatformExtendedPolicy.DeviceCtlMPS;
 
       DEBUG ((
           DEBUG_INFO, "[device policy: platform]"
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.h b/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.h
index a13131c..786c00d 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.h
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciPlatformSupport.h
@@ -124,4 +124,36 @@ EFI_STATUS
 GetPciDevicePlatformPolicy (
   IN PCI_IO_DEVICE          *PciDevice
   );
+
+/**
+  Helper routine to indicate whether the given PCI device specific policy value
+  dictates to override the Max_Payload_Size to a particular value, or set as per
+  device capability.
+
+  @param  MPS     Input device-specific policy should be in terms of type
+                  EFI_PCI_CONF_MAX_PAYLOAD_SIZE
+
+  @retval TRUE    Setup Max_Payload_Size as per device capability
+          FALSE   override as per device-specific platform policy
+**/
+BOOLEAN
+SetupMpsAsPerDeviceCapability (
+  IN  UINT8                   MPS
+);
+
+/**
+  Routine to translate the given device-specific platform policy from type
+  EFI_PCI_CONF_MAX_PAYLOAD_SIZE to HW-specific value, as per PCI Base Specification
+  Revision 4.0; for the PCI feature Max_Payload_Size.
+
+  @param  MPS     Input device-specific policy should be in terms of type
+                  EFI_PCI_CONF_MAX_PAYLOAD_SIZE
+
+  @retval         Range values for the Max_Payload_Size as defined in the PCI
+                  Base Specification 4.0
+**/
+UINT8
+TranslateMpsSetupValueToPci (
+  IN  UINT8                   MPS
+);
 #endif
-- 
2.21.0.windows.1