libgfxinit: Allow to configure screen rotation

This allows to configure a default screen rotation in 90-degree
steps. The framebuffer contents will then be displayed rotated,
by the same amount in the other direction; i.e. if you turn the
screen to the left, the picture has to be rotated to the right
to accommodate.

This is only supported by libgfxinit from Skylake / Apollo Lake
on (earlier GPUs didn't support the 90-degree steps anyway) and
it only works with the linear-framebuffer option.

Change-Id: Iac75cefbd34f28c55ec20ee152fe67351cc48653
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38922
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

2 files changed, 59 insertions, 4 deletions

diff --git a/src/device/Kconfig b/src/device/Kconfig
index 243e23e52a..bcff6fd8b0 100644
--- a/src/device/Kconfig
+++ b/src/device/Kconfig
@@ -519,6 +519,39 @@ config LINEAR_FRAMEBUFFER_MAX_HEIGHT
 	  Set the maximum height of the framebuffer. This may help with
 	  default fonts too tiny for high-resolution displays.
 
+choice DEFAULT_SCREEN_ROTATION
+	prompt "Default screen orientation"
+	depends on LINEAR_FRAMEBUFFER && MAINBOARD_USE_LIBGFXINIT
+	depends on GFX_GMA_GENERATION = "Broxton" || GFX_GMA_GENERATION = "Skylake"
+	default DEFAULT_SCREEN_ROTATION_NONE
+	help
+	  This allows to configure how the physical screen is mounted in
+	  90 degree steps (counter-clockwise). The framebuffer contents
+	  will then be displayed rotated by the same amount in the other
+	  direction; i.e. if you turn the screen to the left, the picture
+	  has to be rotated to the right to accommodate.
+
+config DEFAULT_SCREEN_ROTATION_NONE
+	bool "Non-rotated"
+
+config DEFAULT_SCREEN_ROTATION_90
+	bool "Rotated 90 degrees (rotate framebuffer to the right)"
+
+config DEFAULT_SCREEN_ROTATION_180
+	bool "Rotated 180 degrees"
+
+config DEFAULT_SCREEN_ROTATION_270
+	bool "Rotated 270 degrees (rotate framebuffer to the left)"
+
+endchoice
+
+config DEFAULT_SCREEN_ROTATION_INT
+	int
+	default  90 if DEFAULT_SCREEN_ROTATION_90
+	default 180 if DEFAULT_SCREEN_ROTATION_180
+	default 270 if DEFAULT_SCREEN_ROTATION_270
+	default 0
+
 endmenu # "Display"
 
 config PCI
diff --git a/src/drivers/intel/gma/hires_fb/gma-gfx_init.adb b/src/drivers/intel/gma/hires_fb/gma-gfx_init.adb
index 49d0ca495a..66269b22d7 100644
--- a/src/drivers/intel/gma/hires_fb/gma-gfx_init.adb
+++ b/src/drivers/intel/gma/hires_fb/gma-gfx_init.adb
@@ -21,6 +21,17 @@ is
    configs : Pipe_Configs;
    ----------------------------------------------------------------------------
 
+   procedure Screen_Rotation (rotation : out Rotation_Type)
+   is
+   begin
+      rotation :=
+        (case Config.DEFAULT_SCREEN_ROTATION_INT is
+            when     90 => Rotated_90,
+            when    180 => Rotated_180,
+            when    270 => Rotated_270,
+            when others => No_Rotation);
+   end Screen_Rotation;
+
    procedure gfxinit (lightup_ok : out Interfaces.C.int)
    is
       use type pos32;
@@ -60,10 +71,21 @@ is
             end loop;
 
             fb := configs (Primary).Framebuffer;
-            fb.Width    := Width_Type (min_h);
-            fb.Height   := Height_Type (min_v);
-            fb.Stride   := Div_Round_Up (fb.Width, 16) * 16;
-            fb.V_Stride := fb.Height;
+            Screen_Rotation (fb.Rotation);
+
+            if fb.Rotation = Rotated_90 or fb.Rotation = Rotated_270 then
+               fb.Width    := Width_Type (min_v);
+               fb.Height   := Height_Type (min_h);
+               fb.Stride   := Div_Round_Up (fb.Width, 32) * 32;
+               fb.V_Stride := Div_Round_Up (fb.Height, 32) * 32;
+               fb.Tiling   := Y_Tiled;
+               fb.Offset   := word32 (GTT_Rotation_Offset) * GTT_Page_Size;
+            else
+               fb.Width    := Width_Type (min_h);
+               fb.Height   := Height_Type (min_v);
+               fb.Stride   := Div_Round_Up (fb.Width, 16) * 16;
+               fb.V_Stride := fb.Height;
+            end if;
 
             for i in Pipe_Index loop
                exit when configs (i).Port = Disabled;