drm/i915/bios: add intel_bios_max_tmds_encoder()

Don't access i915->vbt.ddi_port_info[] directly.
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c52c39df43374b51f56439daf8047079afae7749.1579270868.git.jani.nikula@intel.com

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

@@ -2562,3 +2562,10 @@ enum aux_ch intel_bios_port_aux_ch(struct drm_i915_private *dev_priv,
 
 	return aux_ch;
 }
+
+int intel_bios_max_tmds_clock(struct intel_encoder *encoder)
+{
+	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+
+	return i915->vbt.ddi_port_info[encoder->port].max_tmds_clock;
+}

drivers/gpu/drm/i915/display/intel_bios.h

@@ -247,5 +247,6 @@ enum aux_ch intel_bios_port_aux_ch(struct drm_i915_private *dev_priv, enum port
 bool intel_bios_get_dsc_params(struct intel_encoder *encoder,
 			       struct intel_crtc_state *crtc_state,
 			       int dsc_max_bpc);
+int intel_bios_max_tmds_clock(struct intel_encoder *encoder);
 
 #endif /* _INTEL_BIOS_H_ */

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

@@ -2090,9 +2090,7 @@ static void pch_post_disable_hdmi(struct intel_encoder *encoder,
 static int intel_hdmi_source_max_tmds_clock(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
-	const struct ddi_vbt_port_info *info =
-		&dev_priv->vbt.ddi_port_info[encoder->port];
-	int max_tmds_clock;
+	int max_tmds_clock, vbt_max_tmds_clock;
 
 	if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv))
 		max_tmds_clock = 594000;
@@ -2103,8 +2101,9 @@ static int intel_hdmi_source_max_tmds_clock(struct intel_encoder *encoder)
 	else
 		max_tmds_clock = 165000;
 
-	if (info->max_tmds_clock)
-		max_tmds_clock = min(max_tmds_clock, info->max_tmds_clock);
+	vbt_max_tmds_clock = intel_bios_max_tmds_clock(encoder);
+	if (vbt_max_tmds_clock)
+		max_tmds_clock = min(max_tmds_clock, vbt_max_tmds_clock);
 
 	return max_tmds_clock;
 }