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>
3 files changed
tree: 1908d586caf388165f18ba7eeef31a13c1e8d1da
  1. common/
  2. configs/
  3. .gitignore
  4. COPYING
  5. Makefile
  6. Makefile.inc
  7. TODO