drm/i915: Set alternate aux for DDI-E

There is no correspondent Aux channel for DDI-E.

So we need to rely on VBT to let us know witch one
is being used instead.

v2: Removing some trailing spaces and giving proper
credit to Xiong that added a nice way to avoid port
conflicts by setting supports_dp = 0 when using
equivalent aux for DDI-E.

Credits-to: Xiong Zhang <xiong.y.zhang@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Xiong Zhang <xiong.y.zhang@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1409,6 +1409,11 @@ enum modeset_restore {
 	MODESET_SUSPENDED,
 };
 
+#define DP_AUX_A 0x40
+#define DP_AUX_B 0x10
+#define DP_AUX_C 0x20
+#define DP_AUX_D 0x30
+
 struct ddi_vbt_port_info {
 	/*
 	 * This is an index in the HDMI/DVI DDI buffer translation table.
@@ -1421,6 +1426,8 @@ struct ddi_vbt_port_info {
 	uint8_t supports_dvi:1;
 	uint8_t supports_hdmi:1;
 	uint8_t supports_dp:1;
+
+	uint8_t alternate_aux_channel;
 };
 
 enum psr_lines_to_wait {

drivers/gpu/drm/i915/intel_bios.c

@@ -968,13 +968,28 @@ static void parse_ddi_port(struct drm_i915_private *dev_priv, enum port port,
 	}
 
 	if (is_dp) {
-		if (aux_channel == 0x40 && port != PORT_A)
+		if (port == PORT_E) {
+			info->alternate_aux_channel = aux_channel;
+			/* if DDIE share aux channel with other port, then
+			 * DP couldn't exist on the shared port. Otherwise
+			 * they share the same aux channel and system
+			 * couldn't communicate with them seperately. */
+			if (aux_channel == DP_AUX_A)
+				dev_priv->vbt.ddi_port_info[PORT_A].supports_dp = 0;
+			else if (aux_channel == DP_AUX_B)
+				dev_priv->vbt.ddi_port_info[PORT_B].supports_dp = 0;
+			else if (aux_channel == DP_AUX_C)
+				dev_priv->vbt.ddi_port_info[PORT_C].supports_dp = 0;
+			else if (aux_channel == DP_AUX_D)
+				dev_priv->vbt.ddi_port_info[PORT_D].supports_dp = 0;
+		}
+		else if (aux_channel == DP_AUX_A && port != PORT_A)
 			DRM_DEBUG_KMS("Unexpected AUX channel for port A\n");
-		if (aux_channel == 0x10 && port != PORT_B)
+		else if (aux_channel == DP_AUX_B && port != PORT_B)
 			DRM_DEBUG_KMS("Unexpected AUX channel for port B\n");
-		if (aux_channel == 0x20 && port != PORT_C)
+		else if (aux_channel == DP_AUX_C && port != PORT_C)
 			DRM_DEBUG_KMS("Unexpected AUX channel for port C\n");
-		if (aux_channel == 0x30 && port != PORT_D)
+		else if (aux_channel == DP_AUX_D && port != PORT_D)
 			DRM_DEBUG_KMS("Unexpected AUX channel for port D\n");
 	}
 

drivers/gpu/drm/i915/intel_ddi.c

@@ -3184,10 +3184,9 @@ void intel_ddi_init(struct drm_device *dev, enum port port)
 		     dev_priv->vbt.ddi_port_info[port].supports_hdmi);
 	init_dp = dev_priv->vbt.ddi_port_info[port].supports_dp;
 	if (!init_dp && !init_hdmi) {
-		DRM_DEBUG_KMS("VBT says port %c is not DVI/HDMI/DP compatible, assuming it is\n",
+		DRM_DEBUG_KMS("VBT says port %c is not DVI/HDMI/DP compatible, respect it\n",
 			      port_name(port));
-		init_hdmi = true;
-		init_dp = true;
+		return;
 	}
 
 	intel_dig_port = kzalloc(sizeof(*intel_dig_port), GFP_KERNEL);

drivers/gpu/drm/i915/intel_dp.c

@@ -1033,11 +1033,34 @@ static void
 intel_dp_aux_init(struct intel_dp *intel_dp, struct intel_connector *connector)
 {
 	struct drm_device *dev = intel_dp_to_dev(intel_dp);
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
 	enum port port = intel_dig_port->port;
+	struct ddi_vbt_port_info *info = &dev_priv->vbt.ddi_port_info[port];
 	const char *name = NULL;
+	uint32_t porte_aux_ctl_reg = DPA_AUX_CH_CTL;
 	int ret;
 
+	/* On SKL we don't have Aux for port E so we rely on VBT to set
+	 * a proper alternate aux channel.
+	 */
+	if (IS_SKYLAKE(dev) && port == PORT_E) {
+		switch (info->alternate_aux_channel) {
+		case DP_AUX_B:
+			porte_aux_ctl_reg = DPB_AUX_CH_CTL;
+			break;
+		case DP_AUX_C:
+			porte_aux_ctl_reg = DPC_AUX_CH_CTL;
+			break;
+		case DP_AUX_D:
+			porte_aux_ctl_reg = DPD_AUX_CH_CTL;
+			break;
+		case DP_AUX_A:
+		default:
+			porte_aux_ctl_reg = DPA_AUX_CH_CTL;
+		}
+	}
+
 	switch (port) {
 	case PORT_A:
 		intel_dp->aux_ch_ctl_reg = DPA_AUX_CH_CTL;
@@ -1055,6 +1078,10 @@ intel_dp_aux_init(struct intel_dp *intel_dp, struct intel_connector *connector)
 		intel_dp->aux_ch_ctl_reg = PCH_DPD_AUX_CH_CTL;
 		name = "DPDDC-D";
 		break;
+	case PORT_E:
+		intel_dp->aux_ch_ctl_reg = porte_aux_ctl_reg;
+		name = "DPDDC-E";
+		break;
 	default:
 		BUG();
 	}
@@ -1068,7 +1095,7 @@ intel_dp_aux_init(struct intel_dp *intel_dp, struct intel_connector *connector)
 	 *
 	 * Skylake moves AUX_CTL back next to DDI_BUF_CTL, on the CPU.
 	 */
-	if (!IS_HASWELL(dev) && !IS_BROADWELL(dev))
+	if (!IS_HASWELL(dev) && !IS_BROADWELL(dev) && port != PORT_E)
 		intel_dp->aux_ch_ctl_reg = intel_dp->output_reg + 0x10;
 
 	intel_dp->aux.name = name;