[Intel-gfx] [PATCH] drm/i915/icl: remove port A/E lane sharing limitation.

[Mahesh Kumar]

From: "Kumar, Mahesh" <mahesh1.kumar at intel.com>

Platforms before Gen11 were sharing lanes between port-A & port-E.
This limitation is no more there.

Changes since V1:
 - optimize the code (Shashank/Jani)
 - create helper function to get max lanes (ville)

Signed-off-by: Mahesh Kumar <mahesh1.kumar at intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c | 43 +++++++++++++++++-----------------------
 1 file changed, 18 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index e51559be2e3b..4bde742a8ff4 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2842,6 +2842,23 @@ static bool intel_ddi_a_force_4_lanes(struct intel_digital_port *dport)
 	return false;
 }
 
+static int
+intel_ddi_max_lanes(struct drm_i915_private *dev_priv, enum port port)
+{
+	if (INTEL_GEN(dev_priv) >= 11)
+		return 4;
+
+	if (port == PORT_A || port == PORT_E) {
+		if (I915_READ(DDI_BUF_CTL(PORT_A)) & DDI_A_4_LANES)
+			return port == PORT_A ? 4 : 0;
+		else
+			/* Both A and E share 2 lanes */
+			return 2;
+	}
+
+	return 4;
+}
+
 void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 {
 	struct intel_digital_port *intel_dig_port;
@@ -2850,31 +2867,7 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 	bool init_hdmi, init_dp, init_lspcon = false;
 	int max_lanes;
 
-	if (I915_READ(DDI_BUF_CTL(PORT_A)) & DDI_A_4_LANES) {
-		switch (port) {
-		case PORT_A:
-			max_lanes = 4;
-			break;
-		case PORT_E:
-			max_lanes = 0;
-			break;
-		default:
-			max_lanes = 4;
-			break;
-		}
-	} else {
-		switch (port) {
-		case PORT_A:
-			max_lanes = 2;
-			break;
-		case PORT_E:
-			max_lanes = 2;
-			break;
-		default:
-			max_lanes = 4;
-			break;
-		}
-	}
+	max_lanes = intel_ddi_max_lanes(dev_priv, port);
 
 	init_hdmi = (dev_priv->vbt.ddi_port_info[port].supports_dvi ||
 		     dev_priv->vbt.ddi_port_info[port].supports_hdmi);
-- 
2.14.1