MdeModuelPkg/PciBus: Return AddrTranslationOffset in GetBarAttributes

Some platform doesn't use CPU(HOST)/Device 1:1 mapping for PCI Bus.
But PCI IO doesn't have interface to tell caller (device driver)
whether the address returned by GetBarAttributes() is HOST address
or device address.
UEFI Spec 2.6 addresses this issue by clarifying the address returned
is HOST address and caller can use AddrTranslationOffset to calculate
the device address.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

MdeModulePkg/Bus/Pci/PciBusDxe/PciIo.c

@@ -1743,6 +1743,53 @@ PciIoAttributes (
   return Status;
 }
 
+/**
+  Retrieve the AddrTranslationOffset from RootBridgeIo for the
+  specified range.
+
+  @param RootBridgeIo    Root Bridge IO instance.
+  @param AddrRangeMin    The base address of the MMIO.
+  @param AddrLen         The length of the MMIO.
+
+  @retval The AddrTranslationOffset from RootBridgeIo for the 
+          specified range, or (UINT64) -1 if the range is not
+          found in RootBridgeIo.
+**/
+UINT64
+GetMmioAddressTranslationOffset (
+  EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL   *RootBridgeIo,
+  UINT64                            AddrRangeMin,
+  UINT64                            AddrLen
+  )
+{
+  EFI_STATUS                        Status;
+  EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *Configuration;
+
+  Status = RootBridgeIo->Configuration (
+                           RootBridgeIo,
+                           (VOID **) &Configuration
+                           );
+  if (EFI_ERROR (Status)) {
+    return (UINT64) -1;
+  }
+
+  while (Configuration->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR) {
+    if ((Configuration->ResType == ACPI_ADDRESS_SPACE_TYPE_MEM) &&
+        (Configuration->AddrRangeMin <= AddrRangeMin) &&
+        (Configuration->AddrRangeMin + Configuration->AddrLen >= AddrRangeMin + AddrLen)
+        ) {
+      return Configuration->AddrTranslationOffset;
+    }
+    Configuration++;
+  }
+
+  //
+  // The resource occupied by BAR should be in the range reported by RootBridge.
+  //
+  ASSERT (FALSE);
+  return (UINT64) -1;
+}
+
 /**
   Gets the attributes that this PCI controller supports setting on a BAR using
   SetBarAttributes(), and retrieves the list of resource descriptors for a BAR.
@@ -1867,6 +1914,21 @@ PciIoGetBarAttributes (
     End           = (EFI_ACPI_END_TAG_DESCRIPTOR *) (Descriptor + 1);
     End->Desc     = ACPI_END_TAG_DESCRIPTOR;
     End->Checksum = 0;
+
+    //
+    // Get the Address Translation Offset
+    //
+    if (Descriptor->ResType == ACPI_ADDRESS_SPACE_TYPE_MEM) {
+      Descriptor->AddrTranslationOffset = GetMmioAddressTranslationOffset (
+                                            PciIoDevice->PciRootBridgeIo,
+                                            Descriptor->AddrRangeMin,
+                                            Descriptor->AddrLen
+                                            );
+      if (Descriptor->AddrTranslationOffset == (UINT64) -1) {
+        FreePool (Descriptor);
+        return EFI_UNSUPPORTED;
+      }
+    }
   }
 
   return EFI_SUCCESS;