drm/i915: Beef up SDVO/HDMI port checks

The SDVO code already warns when the port in question doesn't
actually support SDVO. Let's make that also bail the encoder
registration like the generic assert_port_valid() we added.

And add a similar thing for g4x HDMI, mainly because on g4x
itsefl port D only supports DP but not SDVO/HDMI. For the
other platforms the generic port_mask check should actually
be sufficient, but since we're here might as well list the
ports.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230616140820.11726-6-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/display/g4x_hdmi.c

@@ -659,6 +659,20 @@ int g4x_hdmi_connector_atomic_check(struct drm_connector *connector,
 	return ret;
 }
 
+static bool is_hdmi_port_valid(struct drm_i915_private *i915, enum port port)
+{
+	if (IS_G4X(i915) || IS_VALLEYVIEW(i915))
+		return port == PORT_B || port == PORT_C;
+	else
+		return port == PORT_B || port == PORT_C || port == PORT_D;
+}
+
+static bool assert_hdmi_port_valid(struct drm_i915_private *i915, enum port port)
+{
+	return !drm_WARN(&i915->drm, !is_hdmi_port_valid(i915, port),
+			 "Platform does not support HDMI %c\n", port_name(port));
+}
+
 void g4x_hdmi_init(struct drm_i915_private *dev_priv,
 		   i915_reg_t hdmi_reg, enum port port)
 {
@@ -670,6 +684,9 @@ void g4x_hdmi_init(struct drm_i915_private *dev_priv,
 	if (!assert_port_valid(dev_priv, port))
 		return;
 
+	if (!assert_hdmi_port_valid(dev_priv, port))
+		return;
+
 	devdata = intel_bios_encoder_data_lookup(dev_priv, port);
 
 	/* FIXME bail? */

drivers/gpu/drm/i915/display/intel_sdvo.c

@@ -3313,13 +3313,19 @@ intel_sdvo_init_ddc_proxy(struct intel_sdvo *sdvo,
 	return i2c_add_adapter(&sdvo->ddc) == 0;
 }
 
-static void assert_sdvo_port_valid(const struct drm_i915_private *dev_priv,
-				   enum port port)
+static bool is_sdvo_port_valid(struct drm_i915_private *dev_priv, enum port port)
 {
 	if (HAS_PCH_SPLIT(dev_priv))
-		drm_WARN_ON(&dev_priv->drm, port != PORT_B);
+		return port == PORT_B;
 	else
-		drm_WARN_ON(&dev_priv->drm, port != PORT_B && port != PORT_C);
+		return port == PORT_B || port == PORT_C;
+}
+
+static bool assert_sdvo_port_valid(struct drm_i915_private *dev_priv,
+				   enum port port)
+{
+	return !drm_WARN(&dev_priv->drm, !is_sdvo_port_valid(dev_priv, port),
+			 "Platform does not support SDVO %c\n", port_name(port));
 }
 
 bool intel_sdvo_init(struct drm_i915_private *dev_priv,
@@ -3332,7 +3338,8 @@ bool intel_sdvo_init(struct drm_i915_private *dev_priv,
 	if (!assert_port_valid(dev_priv, port))
 		return false;
 
-	assert_sdvo_port_valid(dev_priv, port);
+	if (!assert_sdvo_port_valid(dev_priv, port))
+		return false;
 
 	intel_sdvo = kzalloc(sizeof(*intel_sdvo), GFP_KERNEL);
 	if (!intel_sdvo)