diff --git a/common/hw-gfx-dp_defs.ads b/common/hw-gfx-dp_defs.ads
new file mode 100644
index 0000000..9332f9e
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+++ b/common/hw-gfx-dp_defs.ads
@@ -0,0 +1,32 @@
+--
+-- Copyright (C) 2015-2016 secunet Security Networks AG
+--
+-- This program is free software; you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation; version 2 of the License.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+
+package HW.GFX.DP_Defs is
+
+   type Aux_Message_Command is mod 2 ** 4;
+   type Aux_Message_Address is mod 2 ** 20;
+
+   subtype Aux_Payload_Length is Natural range 0 .. 16;
+   subtype Aux_Payload_Index is Natural range 0 .. Aux_Payload_Length'Last - 1;
+   subtype Aux_Payload is Buffer (Aux_Payload_Index);
+
+   subtype Aux_Request_Length is Natural range 3 .. 20;
+   subtype Aux_Request_Index is Natural range 0 .. Aux_Request_Length'Last - 1;
+   subtype Aux_Request is Buffer (Aux_Request_Index);
+
+   subtype Aux_Response_Length is Natural range 1 .. 17;
+   subtype Aux_Response_Index is
+      Natural range 0 .. Aux_Response_Length'Last - 1;
+   subtype Aux_Response is Buffer (Aux_Response_Index);
+
+end HW.GFX.DP_Defs;