Change in libgfxinit[master]: gma hsw+: Don't use DDI E if DDI A uses all lanes

[Nico Huber (Code Review)]

Nico Huber has uploaded this change for review. ( https://review.coreboot.org/20821

Change subject: gma hsw+: Don't use DDI E if DDI A uses all lanes
......................................................................

gma hsw+: Don't use DDI E if DDI A uses all lanes

DDI E shares its two lanes with DDI A. If DDI A is configured to use
all four lanes, DDI E is disabled. As DDI E is the only DDI that can
be configured in FDI mode to feed the PCH DAC, treat `Analog` as in-
valid in this configuration.

Change-Id: I94e9537c9f30d0cbf757b816f38d44e1b43805b3
Signed-off-by: Nico Huber 
---
M common/haswell_shared/hw-gfx-gma-port_detect.adb
M common/hw-gfx-gma-config.ads.template
2 files changed, 11 insertions(+), 2 deletions(-)

git pull ssh://review.coreboot.org:29418/libgfxinit refs/changes/21/20821/1

diff --git a/common/haswell_shared/hw-gfx-gma-port_detect.adb b/common/haswell_shared/hw-gfx-gma-port_detect.adb
index d8a1d07..1302cf0 100644
--- a/common/haswell_shared/hw-gfx-gma-port_detect.adb
+++ b/common/haswell_shared/hw-gfx-gma-port_detect.adb
@@ -19,6 +19,8 @@
 package body HW.GFX.GMA.Port_Detect
 is

+   DDI_BUF_CTL_A_LANE_CAPABILITY_X4    : constant := 1 * 2 **  4;
+
    SFUSE_STRAP_CRT_DAC_CAP_DISABLE     : constant := 1 * 2 **  6;

HOTPLUG_CTL_DDI_A_HPD_INPUT_ENABLE  : constant := 1 * 2 **  4;
@@ -55,6 +57,7 @@

procedure Initialize
    is
+      DDI_A_X4,
       DAC_Disabled,
       Internal_Detected,
       DDI_Detected : Boolean;
@@ -71,13 +74,17 @@
          DIGI_C => DP2,
          DIGI_D => DP3);
    begin
-      if Config.Has_PCH_DAC then
+      if Config.Has_DDI_E and Config.Has_PCH_DAC then
          -- PCH_DAC (_A)
+         Registers.Is_Set_Mask
+           (Register => Registers.DDI_BUF_CTL_A,
+            Mask     => DDI_BUF_CTL_A_LANE_CAPABILITY_X4,
+            Result   => DDI_A_X4);
          Registers.Is_Set_Mask
            (Register => Registers.SFUSE_STRAP,
             Mask     => SFUSE_STRAP_CRT_DAC_CAP_DISABLE,
             Result   => DAC_Disabled);
-         Config.Valid_Port (Analog) := not DAC_Disabled;
+         Config.Valid_Port (Analog) := not (DDI_A_X4 or DAC_Disabled);
       end if;

if Config.Internal_Is_EDP then
diff --git a/common/hw-gfx-gma-config.ads.template b/common/hw-gfx-gma-config.ads.template
index aba00bb..55696c7 100644
--- a/common/hw-gfx-gma-config.ads.template
+++ b/common/hw-gfx-gma-config.ads.template
@@ -91,6 +91,8 @@
    Has_DDI_D               : constant Boolean := CPU >= Haswell and
                                                  CPU_Var = Normal and
                                                  not Has_DDI_PHYs;
+   Has_DDI_E               : constant Boolean := -- might be disabled by x4 eDP
+                                                 Has_DDI_D;

Has_Low_Voltage_Swing   : constant Boolean := CPU >= Broxton;