[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)
Changes since V2:
 - Include BIOS fail fix-up in same helper function (ville)

Signed-off-by: Mahesh Kumar <mahesh1.kumar at intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c | 71 +++++++++++++++++++---------------------
 1 file changed, 33 insertions(+), 38 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index cfcd9cb37d5d..ee9ba78d19c8 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2842,39 +2842,44 @@ 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,
+		    struct intel_digital_port *intel_dig_port)
+{
+	enum port port = intel_dig_port->base.port;
+	int max_lanes = 4;
+
+	if (INTEL_GEN(dev_priv) >= 11) {
+		return 4;
+	} else if (port == PORT_A || port == PORT_E) {
+		if (I915_READ(DDI_BUF_CTL(PORT_A)) & DDI_A_4_LANES)
+			max_lanes = port == PORT_A ? 4 : 0;
+		else
+			/* Both A and E share 2 lanes */
+			max_lanes = 2;
+	}
+
+	/*
+	 * Some BIOS might fail to set this bit on port A if eDP
+	 * wasn't lit up at boot.  Force this bit set when needed
+	 * so we use the proper lane count for our calculations.
+	 */
+	if (intel_ddi_a_force_4_lanes(intel_dig_port)) {
+		DRM_DEBUG_KMS("Forcing DDI_A_4_LANES for port A\n");
+		intel_dig_port->saved_port_bits |= DDI_A_4_LANES;
+		max_lanes = 4;
+	}
+
+	return max_lanes;
+}
+
 void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 {
 	struct intel_digital_port *intel_dig_port;
 	struct intel_encoder *intel_encoder;
 	struct drm_encoder *encoder;
 	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;
-		}
-	}
 
 	init_hdmi = (dev_priv->vbt.ddi_port_info[port].supports_dvi ||
 		     dev_priv->vbt.ddi_port_info[port].supports_hdmi);
@@ -2954,19 +2959,7 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 		MISSING_CASE(port);
 	}
 
-	/*
-	 * Some BIOS might fail to set this bit on port A if eDP
-	 * wasn't lit up at boot.  Force this bit set when needed
-	 * so we use the proper lane count for our calculations.
-	 */
-	if (intel_ddi_a_force_4_lanes(intel_dig_port)) {
-		DRM_DEBUG_KMS("Forcing DDI_A_4_LANES for port A\n");
-		intel_dig_port->saved_port_bits |= DDI_A_4_LANES;
-		max_lanes = 4;
-	}
-
 	intel_dig_port->dp.output_reg = INVALID_MMIO_REG;
-	intel_dig_port->max_lanes = max_lanes;
 
 	intel_encoder->type = INTEL_OUTPUT_DDI;
 	intel_encoder->power_domain = intel_port_to_power_domain(port);
@@ -2974,6 +2967,8 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 	intel_encoder->crtc_mask = (1 << 0) | (1 << 1) | (1 << 2);
 	intel_encoder->cloneable = 0;
 
+	intel_dig_port->max_lanes = intel_ddi_max_lanes(dev_priv,
+							intel_dig_port);
 	intel_infoframe_init(intel_dig_port);
 
 	if (init_dp) {
-- 
2.14.1