diff --git a/common/tigerlake/xelpd/hw-gfx-gma-power_domains.ads b/common/tigerlake/xelpd/hw-gfx-gma-power_domains.ads
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+--
+-- Copyright (C) 2022 Google, LLC
+--
+-- 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.Power_Domains is
+
+   -- Comment lifted from i915:
+   -- XE_LPD Power Domains
+   --
+   -- Previous platforms required that PW(n-1) be enabled before PW(n).  That
+   -- dependency chain turns into a dependency tree on XE_LPD:
+   --
+   --       PW0
+   --        |
+   --     --PW1--
+   --    /       \
+   --  PWA     --PW2--
+   --         /   |   \
+   --       PWB  PWC  PWD
+   --
+   -- Power wells must be enabled from top to bottom and disabled from bottom
+   -- to top.  This allows pipes to be power gated independently.
+
+   type Power_Domain is
+     (PW1, PWA, PW2, PWB, PWC, PWD,
+      -- order matters, bit positions for D & E replace USBC5 & 6 from TGL:
+      AUX_A, AUX_B, AUX_C, AUX_USBC1, AUX_USBC2, AUX_USBC3, AUX_USBC4, AUX_D, AUX_E,
+      DDI_A, DDI_B, DDI_C, DDI_USBC1, DDI_USBC2, DDI_USBC3, DDI_USBC4, DDI_D, DDI_E);
+   subtype Dynamic_Domain  is Power_Domain range PWA .. DDI_E;
+   subtype PW_Domain       is Power_Domain range PW1 .. PWD;
+   subtype Dynamic_Well    is Power_Domain range PWA .. PWD;
+   subtype Port_Domain     is Power_Domain range AUX_A .. DDI_E;
+   subtype DDI_Domain      is Power_Domain range DDI_A .. DDI_E;
+   subtype DDI_PW2_Domain  is Power_Domain range DDI_C .. DDI_E;
+   subtype DDI_USBC_Domain is Power_Domain range DDI_USBC1 .. DDI_USBC4;
+   subtype AUX_Domain      is Power_Domain range AUX_A .. AUX_E;
+   subtype AUX_USBC_Domain is Power_Domain range AUX_USBC1 .. AUX_USBC4;
+
+   ----------------------------------------------------------------------------
+
+   FUSE_STATUS_PGx_DIST_STATUS : constant array (PW_Domain) of Word32 :=
+     (PW1   => 1 * 2 ** 26,
+      PW2   => 1 * 2 ** 25,
+      PWA   => 1 * 2 ** 21,
+      PWB   => 1 * 2 ** 20,
+      PWC   => 1 * 2 ** 19,
+      PWD   => 1 * 2 ** 18);
+
+   ----------------------------------------------------------------------------
+
+   PW_State_Mask : constant array (PW_Domain) of Word32 :=
+     (PW1 => 1 * 2 **  0,
+      PW2 => 1 * 2 **  2,
+      PWA => 1 * 2 ** 10,
+      PWB => 1 * 2 ** 12,
+      PWC => 1 * 2 ** 14,
+      PWD => 1 * 2 ** 16);
+
+   ----------------------------------------------------------------------------
+
+   function To_GPU_Port (PD : Port_Domain) return GPU_Port
+   is
+     (case PD is
+         when DDI_A | AUX_A         => DIGI_A,
+         when DDI_B | AUX_B         => DIGI_B,
+         when DDI_C | AUX_C         => DIGI_C,
+         when DDI_D | AUX_D         => DIGI_D,
+         when DDI_E | AUX_E         => DIGI_E,
+         when DDI_USBC1 | AUX_USBC1 => DDI_TC1,
+         when DDI_USBC2 | AUX_USBC2 => DDI_TC2,
+         when DDI_USBC3 | AUX_USBC3 => DDI_TC3,
+         when DDI_USBC4 | AUX_USBC4 => DDI_TC4);
+
+   ----------------------------------------------------------------------------
+
+   function Need_PW (PW : Dynamic_Well; Configs : Pipe_Configs) return Boolean;
+
+   procedure Power_Up (Port : Active_Port_Type; Success : out Boolean);
+
+end HW.GFX.GMA.Power_Domains;