drm/i915: Enable SDP split for DP2.0

Enable the SDP split configuration for DP2.0.

v2: Move the register handling out of compute config function (JaniN)

v3: Patch styling and register access based on platform support (JaniN)

v4: Rebased

v5: Use unconditional clear bit in intel_de_rmw (Jani Nikula)

Bspec: 67768
Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221121150718.1117628-1-vinod.govindapillai@intel.com

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

@@ -798,6 +798,17 @@ static void ilk_audio_codec_enable(struct intel_encoder *encoder,
 	mutex_unlock(&i915->display.audio.mutex);
 }
 
+void intel_audio_sdp_split_update(struct intel_encoder *encoder,
+				  const struct intel_crtc_state *crtc_state)
+{
+	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+	enum transcoder trans = crtc_state->cpu_transcoder;
+
+	if (HAS_DP20(i915))
+		intel_de_rmw(i915, AUD_DP_2DOT0_CTRL(trans), AUD_ENABLE_SDP_SPLIT,
+			     crtc_state->sdp_split_enable ? AUD_ENABLE_SDP_SPLIT : 0);
+}
+
 /**
  * intel_audio_codec_enable - Enable the audio codec for HD audio
  * @encoder: encoder on which to enable audio

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

@@ -22,5 +22,7 @@ void intel_audio_cdclk_change_pre(struct drm_i915_private *dev_priv);
 void intel_audio_cdclk_change_post(struct drm_i915_private *dev_priv);
 void intel_audio_init(struct drm_i915_private *dev_priv);
 void intel_audio_deinit(struct drm_i915_private *dev_priv);
+void intel_audio_sdp_split_update(struct intel_encoder *encoder,
+				  const struct intel_crtc_state *crtc_state);
 
 #endif /* __INTEL_AUDIO_H__ */

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

@@ -2948,6 +2948,9 @@ static void intel_enable_ddi(struct intel_atomic_state *state,
 
 	intel_vrr_enable(encoder, crtc_state);
 
+	/* Enable/Disable DP2.0 SDP split config before transcoder */
+	intel_audio_sdp_split_update(encoder, crtc_state);
+
 	intel_enable_transcoder(crtc_state);
 
 	intel_crtc_vblank_on(crtc_state);

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

@@ -1295,6 +1295,8 @@ struct intel_crtc_state {
 	/* Forward Error correction State */
 	bool fec_enable;
 
+	bool sdp_split_enable;
+
 	/* Pointer to master transcoder in case of tiled displays */
 	enum transcoder master_transcoder;
 

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

@@ -2009,6 +2009,23 @@ intel_dp_compute_output_format(struct intel_encoder *encoder,
 	return ret;
 }
 
+static void
+intel_dp_audio_compute_config(struct intel_encoder *encoder,
+			      struct intel_crtc_state *pipe_config,
+			      struct drm_connector_state *conn_state)
+{
+	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+	struct drm_connector *connector = conn_state->connector;
+
+	pipe_config->sdp_split_enable =
+		intel_dp_has_audio(encoder, pipe_config, conn_state) &&
+		intel_dp_is_uhbr(pipe_config);
+
+	drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] SDP split enable: %s\n",
+		    connector->base.id, connector->name,
+		    str_yes_no(pipe_config->sdp_split_enable));
+}
+
 int
 intel_dp_compute_config(struct intel_encoder *encoder,
 			struct intel_crtc_state *pipe_config,
@@ -2092,6 +2109,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 		adjusted_mode->crtc_clock /= n;
 	}
 
+	intel_dp_audio_compute_config(encoder, pipe_config, conn_state);
+
 	intel_link_compute_m_n(output_bpp,
 			       pipe_config->lane_count,
 			       adjusted_mode->crtc_clock,