gma: Add option for VGA plane on the primary pipe
Add special VGA_PLANE_FRAMEBUFFER_OFFSET that, if set on the primary
pipe, toggles the use of the legacy VGA plane instead of the `hires`
plane.
The caller is responsible for the configuration of the VGA plane and
has to specify the framebuffer width and height accordingly.
Change-Id: I9f678fe033d835c9183fbb2d2b05b6585eb545ca
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/17276
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
diff --git a/common/hw-gfx-gma.ads b/common/hw-gfx-gma.ads
index 1e64cb4..ed240ca 100644
--- a/common/hw-gfx-gma.ads
+++ b/common/hw-gfx-gma.ads
@@ -58,6 +58,10 @@
type Config_Index is (Primary, Secondary, Tertiary);
type Configs_Type is array (Config_Index) of Config_Type;
+ -- Special framebuffer offset to indicate legacy VGA plane.
+ -- Only valid on primary pipe.
+ VGA_PLANE_FRAMEBUFFER_OFFSET : constant := 16#ffff_ffff#;
+
procedure Initialize
(MMIO_Base : in Word64 := 0;
Write_Delay : in Word64 := 0;