coreboot_tables: specify clear interface for lb_framebuffer()

For some reason the "interface" for adding framebuffer information
is sitting in src/include/vbe.h while also guarding the call to
fill_lb_framebuffer() with vbe_mode_info_valid() along with some
macro if CONFIG_* for good measure.

Move the fill_lb_framebuffer() declaration to coreboot_tables.h and
provide a comment about how it should be used. Also, now that
there's no need for the notion of a global vbe_mode_info_valid()
remove it from the conditional call path of fill_lb_framebuffer().

Change-Id: Ib3ade6314624091ae70424664527a02b279d0c9b
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/19729
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

3 files changed, 35 insertions, 37 deletions

diff --git a/src/drivers/intel/gma/gma.ads b/src/drivers/intel/gma/gma.ads
index d912df1635..157ec89fcc 100644
--- a/src/drivers/intel/gma/gma.ads
+++ b/src/drivers/intel/gma/gma.ads
@@ -15,9 +15,6 @@ is
 
    ----------------------------------------------------------------------------
 
-   function vbe_mode_info_valid return Interfaces.C.int;
-   pragma Export (C, vbe_mode_info_valid, "vbe_mode_info_valid");
-
    type lb_framebuffer is record
       tag                  : word32;
       size                 : word32;
@@ -37,7 +34,9 @@ is
       reserved_mask_size   : word8;
    end record;
 
-   procedure fill_lb_framebuffer (framebuffer : out lb_framebuffer);
+   function fill_lb_framebuffer
+     (framebuffer : in out lb_framebuffer)
+      return Interfaces.C.int;
    pragma Export (C, fill_lb_framebuffer, "fill_lb_framebuffer");
 
 end GMA;
diff --git a/src/drivers/intel/gma/hires_fb/gma.adb b/src/drivers/intel/gma/hires_fb/gma.adb
index 0ee4a73212..7fe4e1200d 100644
--- a/src/drivers/intel/gma/hires_fb/gma.adb
+++ b/src/drivers/intel/gma/hires_fb/gma.adb
@@ -12,38 +12,40 @@ with GMA.Mainboard;
 package body GMA
 is
 
-   vbe_valid : boolean := false;
+   fb_valid : boolean := false;
 
    linear_fb_addr : word64;
 
    fb : Framebuffer_Type;
 
-   function vbe_mode_info_valid return Interfaces.C.int
-   is
-   begin
-      return (if vbe_valid then 1 else 0);
-   end vbe_mode_info_valid;
-
-   procedure fill_lb_framebuffer (framebuffer : out lb_framebuffer)
+   function fill_lb_framebuffer
+     (framebuffer : in out lb_framebuffer)
+      return Interfaces.C.int
    is
       use type word32;
+      use type Interfaces.C.int;
    begin
-      framebuffer :=
-        (tag                  =>  0,
-         size                 =>  0,
-         physical_address     => linear_fb_addr,
-         x_resolution         => word32 (fb.Width),
-         y_resolution         => word32 (fb.Height),
-         bytes_per_line       => 4 * word32 (fb.Stride),
-         bits_per_pixel       => 32,
-         reserved_mask_pos    => 24,
-         reserved_mask_size   =>  8,
-         red_mask_pos         => 16,
-         red_mask_size        =>  8,
-         green_mask_pos       =>  8,
-         green_mask_size      =>  8,
-         blue_mask_pos        =>  0,
-         blue_mask_size       =>  8);
+      if fb_valid then
+         framebuffer :=
+           (tag                  =>  0,
+            size                 =>  0,
+            physical_address     => linear_fb_addr,
+            x_resolution         => word32 (fb.Width),
+            y_resolution         => word32 (fb.Height),
+            bytes_per_line       => 4 * word32 (fb.Stride),
+            bits_per_pixel       => 32,
+            reserved_mask_pos    => 24,
+            reserved_mask_size   =>  8,
+            red_mask_pos         => 16,
+            red_mask_size        =>  8,
+            green_mask_pos       =>  8,
+            green_mask_size      =>  8,
+            blue_mask_pos        =>  0,
+            blue_mask_size       =>  8);
+         return 0;
+      else
+         return -1;
+      end if;
    end fill_lb_framebuffer;
 
    ----------------------------------------------------------------------------
@@ -102,7 +104,7 @@ is
             HW.GFX.GMA.Update_Outputs (configs);
 
             linear_fb_addr := linear_fb;
-            vbe_valid := true;
+            fb_valid := true;
 
             lightup_ok := 1;
          end if;
diff --git a/src/drivers/intel/gma/text_fb/gma.adb b/src/drivers/intel/gma/text_fb/gma.adb
index 5df203b580..6453571d8c 100644
--- a/src/drivers/intel/gma/text_fb/gma.adb
+++ b/src/drivers/intel/gma/text_fb/gma.adb
@@ -11,16 +11,13 @@ with GMA.Mainboard;
 package body GMA
 is
 
-   function vbe_mode_info_valid return Interfaces.C.int
+   function fill_lb_framebuffer
+     (framebuffer : in out lb_framebuffer)
+      return Interfaces.C.int
    is
+      use type Interfaces.C.int;
    begin
-      return 0;
-   end vbe_mode_info_valid;
-
-   procedure fill_lb_framebuffer (framebuffer : out lb_framebuffer)
-   is
-   begin
-      null;
+      return -1;
    end fill_lb_framebuffer;
 
    ----------------------------------------------------------------------------