Angel Pons has uploaded this change for review.

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gma registers: Allow to specify an offset for display registers

Certain platforms, namely Bay Trail and Braswell, have the display
engine registers at an offset relative to GTTMMADR base. Apart from
that, the registers are rather similar to the ones on GMCH platforms.

Allow platforms to specify at which offset within GTTMM the display
registers are located. Use zero for all currently-supported platforms.

Change-Id: Id5497a23776e9aa9e2fd5ca0479030cb8e55712f
Signed-off-by: Angel Pons <>
M common/
M common/hw-gfx-gma-registers.adb
2 files changed, 3 insertions(+), 1 deletion(-)

git pull ssh:// refs/changes/86/44786/1
diff --git a/common/ b/common/
index 241fe8e..ecbd908 100644
--- a/common/
+++ b/common/
@@ -55,6 +55,8 @@

Default_MMIO_Base : constant := <<DEFAULT_MMIO_BASE>>;

+ Display_Base_Offset : constant := 0;
LVDS_Dual_Threshold : constant := 95_000_000;

Ignore_Presence_Straps : constant Boolean := <<IGNORE_STRAPS>>;
diff --git a/common/hw-gfx-gma-registers.adb b/common/hw-gfx-gma-registers.adb
index 3f0d7ae..5ea134a 100644
--- a/common/hw-gfx-gma-registers.adb
+++ b/common/hw-gfx-gma-registers.adb
@@ -211,7 +211,7 @@
SPARK_Mode => Off
- return Reg'Enum_Rep;
+ return Reg'Enum_Rep + Config.Display_Base_Offset;
end Index;
end Rep;

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Gerrit-Project: libgfxinit
Gerrit-Branch: master
Gerrit-Change-Id: Id5497a23776e9aa9e2fd5ca0479030cb8e55712f
Gerrit-Change-Number: 44786
Gerrit-PatchSet: 1
Gerrit-Owner: Angel Pons <>
Gerrit-MessageType: newchange