diff --git a/common/broxton/hw-gfx-gma-plls.ads b/common/broxton/hw-gfx-gma-plls.ads
new file mode 100644
index 0000000..195b2f3
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+++ b/common/broxton/hw-gfx-gma-plls.ads
@@ -0,0 +1,46 @@
+--
+-- Copyright (C) 2017 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; either version 2 of the License, or
+-- (at your option) any later version.
+--
+-- 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.
+--
+
+private package HW.GFX.GMA.PLLs
+with
+   Abstract_State => (State with Part_Of => GMA.State)
+is
+
+   -- Broxton DDI PHY PLLs are tied to the port.
+   -- So the allocation will be a stub.
+
+   -- XXX: Types should be private (but that triggers a bug in SPARK GPL 2016)
+   type T is (Invalid_PLL, DPLL_A, DPLL_B, DPLL_C);
+   Invalid : constant T := Invalid_PLL;
+
+   procedure Initialize is null
+   with
+      Global => (Output => State);
+
+   procedure Alloc
+     (Port_Cfg : in     Port_Config;
+      PLL      :    out T;
+      Success  :    out Boolean);
+
+   pragma Warnings (GNATprove, Off, "subprogram ""*"" has no effect");
+   procedure Free (PLL : T);
+
+   procedure All_Off;
+   pragma Warnings (GNATprove, On, "subprogram ""*"" has no effect");
+
+   pragma Warnings (GNATprove, Off, "unused variable ""PLL""");
+   function Register_Value (PLL : T) return Word32;
+   pragma Warnings (GNATprove, On, "unused variable ""PLL""");
+
+end HW.GFX.GMA.PLLs;