commit 960e239abb429da6f9c6718d12ffd5d649fa9892
author Arthur Heymans <arthur@aheymans.xyz> Tue Mar 03 19:45:24 2026 +0100
committer Nico Huber <nico.h@gmx.de> Sat Jun 06 10:23:00 2026 +0000
tree 0d2d212be1aa9e55fe93bcf503fe17048a96b99d
parent 3c3828add50024e90e57d6fbe0e660d1b66302d9

gma: Add Intel i945 (Gen3) graphics init support

Add i945G (desktop) and i945GM (mobile) generation support, modeled
after the existing G45 generation code with hardware-specific
adaptations based on the Linux i915 DRM driver and coreboot.

Key hardware differences from G45 (Gen4):
- GTT on separate PCI BAR3 (not within BAR0)
- Simple 32-bit GTT PTEs (addr[31:12] | valid[0])
- No DSPSURF register (uses DSPADDR/DSPLINOFF instead)
- Gen3 fence registers: 32-bit at split 0x2000/0x3000 addresses
- Different PLL limits (VCO 1400-2800 MHz, 96 MHz refclk)
- SDVO multiplier in DPLL register bits[7:4]
- LVDS restricted to Pipe B (pre-i965 requirement)
- CDClk: fixed 400 MHz (desktop) or GCFGC-based (mobile)
- No HDMI/DP, only VGA, LVDS, and SDVO outputs
- PCI IDs: 0x2772 (I945G), 0x27a2/0x27ae (I945GM)

TESTED with thinkpad x60: LVDS & VGA works with a linear framebuffer.

Change-Id: Ib67b3d0ee5e06df427869dce4db926ba57a80fd8
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.sourcearcade.org/c/libgfxinit/+/476
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: Nico Huber <nico.h@gmx.de>

common/hw-gfx-gma.ads

diff --git a/common/hw-gfx-gma.ads b/common/hw-gfx-gma.ads
index 43e88e1..c05f4f1 100644
--- a/common/hw-gfx-gma.ads
+++ b/common/hw-gfx-gma.ads
@@ -35,10 +35,12 @@
    subtype GTT_Range is Natural range 0 .. 16#8_0000# - 1;
    GTT_Rotation_Offset : constant GTT_Range := GTT_Range'Last / 2 + 1;
 
-   type Generation is (G45, Ironlake, Haswell, Broxton, Skylake, Tigerlake);
+   type Generation is (I945, G45, Ironlake, Haswell, Broxton, Skylake, Tigerlake);
 
    type CPU_Type is
-     (G45,
+     (I945G,
+      I945GM,
+      G45,
       GM45,
       Ironlake,
       Sandybridge,
@@ -227,6 +229,13 @@
          In_Out => Device_State, Proof_In => Init_State),
       Pre => Is_Initialized;
 
+   procedure GTT_Entry_Count (Count : out Natural)
+   with
+      Global =>
+        (Input => State,
+         In_Out => Device_State, Proof_In => Init_State),
+      Pre => Is_Initialized and HW.Config.Dynamic_MMIO;
+
    procedure Setup_Default_FB
      (FB       : in     Framebuffer_Type;
       Clear    : in     Boolean := True;