drm/i915: Implement port sync for SKL+

Transcoder port sync was introduced to the hardware in BDW. We
can trivially enable it for SKL+ since the same codepaths are
already used for ICL+ port sync. The only difference is the actual
location of the bits we need to poke.

We leave BDW out (at least for now) since it uses different modeset
paths that haven't been adapted for port sync, and IIRC using the
feature would involve some extra workarounds we've not implemented.

Pre-BDW hardware does not support port sync so we'd have to tweak
the modeset sequence to start the pipes as close together as possible
and hope for the best. So far no one has seriously tried to implement
that.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/27Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200313164831.5980-9-ville.syrjala@linux.intel.comReviewed-by: Manasi Navare <manasi.d.navare@intel.com>

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

@@ -1497,6 +1497,14 @@ void intel_ddi_set_dp_msa(const struct intel_crtc_state *crtc_state,
 	intel_de_write(dev_priv, TRANS_MSA_MISC(cpu_transcoder), temp);
 }
 
+static u32 bdw_trans_port_sync_master_select(enum transcoder master_transcoder)
+{
+	if (master_transcoder == TRANSCODER_EDP)
+		return 0;
+	else
+		return master_transcoder + 1;
+}
+
 /*
  * Returns the TRANS_DDI_FUNC_CTL value based on CRTC state.
  *
@@ -1597,6 +1605,15 @@ intel_ddi_transcoder_func_reg_val_get(const struct intel_crtc_state *crtc_state)
 		temp |= DDI_PORT_WIDTH(crtc_state->lane_count);
 	}
 
+	if (IS_GEN_RANGE(dev_priv, 8, 10) &&
+	    crtc_state->master_transcoder != INVALID_TRANSCODER) {
+		u8 master_select =
+			bdw_trans_port_sync_master_select(crtc_state->master_transcoder);
+
+		temp |= TRANS_DDI_PORT_SYNC_ENABLE |
+			TRANS_DDI_PORT_SYNC_MASTER_SELECT(master_select);
+	}
+
 	return temp;
 }
 
@@ -1612,12 +1629,8 @@ void intel_ddi_enable_transcoder_func(const struct intel_crtc_state *crtc_state)
 		u32 ctl2 = 0;
 
 		if (master_transcoder != INVALID_TRANSCODER) {
-			u8 master_select;
-
-			if (master_transcoder == TRANSCODER_EDP)
-				master_select = 0;
-			else
-				master_select = master_transcoder + 1;
+			u8 master_select =
+				bdw_trans_port_sync_master_select(master_transcoder);
 
 			ctl2 |= PORT_SYNC_MODE_ENABLE |
 				PORT_SYNC_MODE_MASTER_SELECT(master_select);
@@ -1662,8 +1675,13 @@ void intel_ddi_disable_transcoder_func(const struct intel_crtc_state *crtc_state
 			       TRANS_DDI_FUNC_CTL2(cpu_transcoder), 0);
 
 	ctl = intel_de_read(dev_priv, TRANS_DDI_FUNC_CTL(cpu_transcoder));
+
 	ctl &= ~TRANS_DDI_FUNC_ENABLE;
 
+	if (IS_GEN_RANGE(dev_priv, 8, 10))
+		ctl &= ~(TRANS_DDI_PORT_SYNC_ENABLE |
+			 TRANS_DDI_PORT_SYNC_MASTER_SELECT_MASK);
+
 	if (INTEL_GEN(dev_priv) >= 12) {
 		if (!intel_dp_mst_is_master_trans(crtc_state)) {
 			ctl &= ~(TGL_TRANS_DDI_PORT_MASK |
@@ -1672,6 +1690,7 @@ void intel_ddi_disable_transcoder_func(const struct intel_crtc_state *crtc_state
 	} else {
 		ctl &= ~(TRANS_DDI_PORT_MASK | TRANS_DDI_MODE_SELECT_MASK);
 	}
+
 	intel_de_write(dev_priv, TRANS_DDI_FUNC_CTL(cpu_transcoder), ctl);
 
 	if (dev_priv->quirks & QUIRK_INCREASE_DDI_DISABLED_TIME &&
@@ -3916,17 +3935,26 @@ void intel_ddi_compute_min_voltage_level(struct drm_i915_private *dev_priv,
 		crtc_state->min_voltage_level = 2;
 }
 
-static enum transcoder transcoder_master_readout(struct drm_i915_private *dev_priv,
+static enum transcoder bdw_transcoder_master_readout(struct drm_i915_private *dev_priv,
 						     enum transcoder cpu_transcoder)
 {
-	u32 ctl2, master_select;
+	u32 master_select;
 
-	ctl2 = intel_de_read(dev_priv, TRANS_DDI_FUNC_CTL2(cpu_transcoder));
+	if (INTEL_GEN(dev_priv) >= 11) {
+		u32 ctl2 = intel_de_read(dev_priv, TRANS_DDI_FUNC_CTL2(cpu_transcoder));
 
 		if ((ctl2 & PORT_SYNC_MODE_ENABLE) == 0)
 			return INVALID_TRANSCODER;
 
 		master_select = REG_FIELD_GET(PORT_SYNC_MODE_MASTER_SELECT_MASK, ctl2);
+	} else {
+		u32 ctl = intel_de_read(dev_priv, TRANS_DDI_FUNC_CTL(cpu_transcoder));
+
+		if ((ctl & TRANS_DDI_PORT_SYNC_ENABLE) == 0)
+			return INVALID_TRANSCODER;
+
+		master_select = REG_FIELD_GET(TRANS_DDI_PORT_SYNC_MASTER_SELECT_MASK, ctl);
+	}
 
 	if (master_select == 0)
 		return TRANSCODER_EDP;
@@ -3934,7 +3962,7 @@ static enum transcoder transcoder_master_readout(struct drm_i915_private *dev_pr
 		return master_select - 1;
 }
 
-static void icl_get_trans_port_sync_config(struct intel_crtc_state *crtc_state)
+static void bdw_get_trans_port_sync_config(struct intel_crtc_state *crtc_state)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
 	u32 transcoders = BIT(TRANSCODER_A) | BIT(TRANSCODER_B) |
@@ -3942,7 +3970,7 @@ static void icl_get_trans_port_sync_config(struct intel_crtc_state *crtc_state)
 	enum transcoder cpu_transcoder;
 
 	crtc_state->master_transcoder =
-		transcoder_master_readout(dev_priv, crtc_state->cpu_transcoder);
+		bdw_transcoder_master_readout(dev_priv, crtc_state->cpu_transcoder);
 
 	for_each_cpu_transcoder_masked(dev_priv, cpu_transcoder, transcoders) {
 		enum intel_display_power_domain power_domain;
@@ -3955,7 +3983,7 @@ static void icl_get_trans_port_sync_config(struct intel_crtc_state *crtc_state)
 		if (!trans_wakeref)
 			continue;
 
-		if (transcoder_master_readout(dev_priv, cpu_transcoder) ==
+		if (bdw_transcoder_master_readout(dev_priv, cpu_transcoder) ==
 		    crtc_state->cpu_transcoder)
 			crtc_state->sync_mode_slaves_mask |= BIT(cpu_transcoder);
 
@@ -4121,8 +4149,8 @@ void intel_ddi_get_config(struct intel_encoder *encoder,
 			     HDMI_INFOFRAME_TYPE_DRM,
 			     &pipe_config->infoframes.drm);
 
-	if (INTEL_GEN(dev_priv) >= 11)
-		icl_get_trans_port_sync_config(pipe_config);
+	if (INTEL_GEN(dev_priv) >= 8)
+		bdw_get_trans_port_sync_config(pipe_config);
 }
 
 static enum intel_output_type
@@ -4224,7 +4252,11 @@ intel_ddi_port_sync_transcoders(const struct intel_crtc_state *ref_crtc_state,
 	u8 transcoders = 0;
 	int i;
 
-	if (INTEL_GEN(dev_priv) < 11)
+	/*
+	 * We don't enable port sync on BDW due to missing w/as and
+	 * due to not having adjusted the modeset sequence appropriately.
+	 */
+	if (INTEL_GEN(dev_priv) < 9)
 		return 0;
 
 	if (!intel_crtc_has_type(ref_crtc_state, INTEL_OUTPUT_DP))

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

@@ -7060,7 +7060,11 @@ static int intel_dp_connector_atomic_check(struct drm_connector *conn,
 	if (ret)
 		return ret;
 
-	if (INTEL_GEN(dev_priv) < 11)
+	/*
+	 * We don't enable port sync on BDW due to missing w/as and
+	 * due to not having adjusted the modeset sequence appropriately.
+	 */
+	if (INTEL_GEN(dev_priv) < 9)
 		return 0;
 
 	if (!intel_connector_needs_modeset(state, conn))

drivers/gpu/drm/i915/i915_reg.h

@@ -9790,8 +9790,11 @@ enum skl_power_gate {
 #define  TRANS_DDI_BPC_10		(1 << 20)
 #define  TRANS_DDI_BPC_6		(2 << 20)
 #define  TRANS_DDI_BPC_12		(3 << 20)
+#define  TRANS_DDI_PORT_SYNC_MASTER_SELECT_MASK	REG_GENMASK(19, 18) /* bdw-cnl */
+#define  TRANS_DDI_PORT_SYNC_MASTER_SELECT(x)	REG_FIELD_PREP(TRANS_DDI_PORT_SYNC_MASTER_SELECT_MASK, (x))
 #define  TRANS_DDI_PVSYNC		(1 << 17)
 #define  TRANS_DDI_PHSYNC		(1 << 16)
+#define  TRANS_DDI_PORT_SYNC_ENABLE	REG_BIT(15) /* bdw-cnl */
 #define  TRANS_DDI_EDP_INPUT_MASK	(7 << 12)
 #define  TRANS_DDI_EDP_INPUT_A_ON	(0 << 12)
 #define  TRANS_DDI_EDP_INPUT_A_ONOFF	(4 << 12)