1 files changed, 32 insertions, 2 deletions
diff --git a/MdeModulePkg/Include/Guid/OverrideVariable.h b/MdeModulePkg/Include/Guid/OverrideVariable.h
index 3cd5b0333f..2e6601d5a5 100644
--- a/MdeModulePkg/Include/Guid/OverrideVariable.h
+++ b/MdeModulePkg/Include/Guid/OverrideVariable.h
@@ -1,7 +1,37 @@
 /** @file
   This file defines the platform driver override variable name and variable guid.
-
-Copyright (c) 2008, Intel Corporation
+  The variable(s) contain the override mappings from Controller Device Path to a set of Driver Device Paths.
+  
+  VariableLayout {
+  //
+  // NotEnd indicate whether the variable is the last one, and has no subsequent variable need to load.
+  // Each variable has MaximumVariableSize limitation, so multiple variables are required to store
+  // large mapping infos.
+  // The variable(s) name rule is PlatDriOver, PlatDriOver1, PlatDriOver2, ....
+  //
+  UINT32                         NotEnd;               //Zero is the last one.
+  //
+  // The entry which contains the mapping that Controller Device Path to a set of Driver Device Paths
+  // There are often multi mapping entries in a variable.
+  //
+  UINT32                         SIGNATURE;            //SIGNATURE_32('p','d','o','i')
+  UINT32                         DriverNum;
+  EFI_DEVICE_PATH_PROTOCOL       ControllerDevicePath[];
+  EFI_DEVICE_PATH_PROTOCOL       DriverDevicePath[];
+  EFI_DEVICE_PATH_PROTOCOL       DriverDevicePath[];
+  EFI_DEVICE_PATH_PROTOCOL       DriverDevicePath[];
+  ......
+  UINT32                         NotEnd;                //Zero is the last one.
+  UINT32                         SIGNATURE;
+  UINT32                         DriverNum;
+  EFI_DEVICE_PATH_PROTOCOL       ControllerDevicePath[];
+  EFI_DEVICE_PATH_PROTOCOL       DriverDevicePath[];
+  EFI_DEVICE_PATH_PROTOCOL       DriverDevicePath[];
+  EFI_DEVICE_PATH_PROTOCOL       DriverDevicePath[];
+  ......
+  }
+
+Copyright (c) 2008 - 2009, Intel Corporation
 All rights reserved. This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
 which accompanies this distribution.  The full text of the license may be found at