drm/i915/icl: Implement voltage swing programming sequence for Combo PHY DDI

This is an important part of the DDI initalization as well as
for changing the voltage during DisplayPort link training.

The Voltage swing seqeuence is similar to Cannonlake.
However it has different register definitions and hence
it makes sense to create a separate vswing sequence and
program functions for ICL to leave room for more changes
in case the Bspec changes later and deviates from CNL sequence.

v2:
Use ~TAP3_DISABLE for enbaling that bit (Jani Nikula)

v3:
* Use dw4_scaling column for PORT_TX_DW4 values (Rodrigo)

v4:
* Call it combo_vswing, use switch statement (Paulo)

v5 (from Paulo):
* Fix a typo.
* s/rate < 600000/rate <= 600000/.
* Don't remove blank lines that should be there.

v6:
* Rebased by Rodrigo on top of Cannonlake changes
  where non vswing sequences are not aligned with iboost
  anymore.

v7: Another rebase after an upstream rework.

v8 (from Paulo):
* Adjust the code to the upstream output type changes.
* Squash the patch that moved some functions up.
* Merge both get_combo_buf_trans functions in order to simplify the
  code.
* Change the changelog format.

v9 (from Paulo):
* Use RTERM_SELECT instead of SCALING_MODE_SEL.
* Adjust the output type handling according to how the other platforms
  do it now.

v10 (from Paulo):
* Fix comment left out from v9 changes (Rodrigo).

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: James Ausmus <james.ausmus@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180328215803.13835-8-paulo.r.zanoni@intel.com

drivers/gpu/drm/i915/intel_ddi.c

@@ -870,6 +870,45 @@ cnl_get_buf_trans_edp(struct drm_i915_private *dev_priv, int *n_entries)
 	}
 }
 
+static const struct icl_combo_phy_ddi_buf_trans *
+icl_get_combo_buf_trans(struct drm_i915_private *dev_priv, enum port port,
+			int type, int *n_entries)
+{
+	u32 voltage = I915_READ(ICL_PORT_COMP_DW3(port)) & VOLTAGE_INFO_MASK;
+
+	if (type == INTEL_OUTPUT_EDP && dev_priv->vbt.edp.low_vswing) {
+		switch (voltage) {
+		case VOLTAGE_INFO_0_85V:
+			*n_entries = ARRAY_SIZE(icl_combo_phy_ddi_translations_edp_0_85V);
+			return icl_combo_phy_ddi_translations_edp_0_85V;
+		case VOLTAGE_INFO_0_95V:
+			*n_entries = ARRAY_SIZE(icl_combo_phy_ddi_translations_edp_0_95V);
+			return icl_combo_phy_ddi_translations_edp_0_95V;
+		case VOLTAGE_INFO_1_05V:
+			*n_entries = ARRAY_SIZE(icl_combo_phy_ddi_translations_edp_1_05V);
+			return icl_combo_phy_ddi_translations_edp_1_05V;
+		default:
+			MISSING_CASE(voltage);
+			return NULL;
+		}
+	} else {
+		switch (voltage) {
+		case VOLTAGE_INFO_0_85V:
+			*n_entries = ARRAY_SIZE(icl_combo_phy_ddi_translations_dp_hdmi_0_85V);
+			return icl_combo_phy_ddi_translations_dp_hdmi_0_85V;
+		case VOLTAGE_INFO_0_95V:
+			*n_entries = ARRAY_SIZE(icl_combo_phy_ddi_translations_dp_hdmi_0_95V);
+			return icl_combo_phy_ddi_translations_dp_hdmi_0_95V;
+		case VOLTAGE_INFO_1_05V:
+			*n_entries = ARRAY_SIZE(icl_combo_phy_ddi_translations_dp_hdmi_1_05V);
+			return icl_combo_phy_ddi_translations_dp_hdmi_1_05V;
+		default:
+			MISSING_CASE(voltage);
+			return NULL;
+		}
+	}
+}
+
 static int intel_ddi_hdmi_level(struct drm_i915_private *dev_priv, enum port port)
 {
 	int n_entries, level, default_entry;
@@ -2182,6 +2221,146 @@ static void cnl_ddi_vswing_sequence(struct intel_encoder *encoder,
 	I915_WRITE(CNL_PORT_TX_DW5_GRP(port), val);
 }
 
+static void icl_ddi_combo_vswing_program(struct drm_i915_private *dev_priv,
+					 u32 level, enum port port, int type)
+{
+	const struct icl_combo_phy_ddi_buf_trans *ddi_translations = NULL;
+	u32 n_entries, val;
+	int ln;
+
+	ddi_translations = icl_get_combo_buf_trans(dev_priv, port, type,
+						   &n_entries);
+	if (!ddi_translations)
+		return;
+
+	if (level >= n_entries) {
+		DRM_DEBUG_KMS("DDI translation not found for level %d. Using %d instead.", level, n_entries - 1);
+		level = n_entries - 1;
+	}
+
+	/* Set PORT_TX_DW5 Rterm Sel to 110b. */
+	val = I915_READ(ICL_PORT_TX_DW5_LN0(port));
+	val &= ~RTERM_SELECT_MASK;
+	val |= RTERM_SELECT(0x6);
+	I915_WRITE(ICL_PORT_TX_DW5_GRP(port), val);
+
+	/* Program PORT_TX_DW5 */
+	val = I915_READ(ICL_PORT_TX_DW5_LN0(port));
+	/* Set DisableTap2 and DisableTap3 if MIPI DSI
+	 * Clear DisableTap2 and DisableTap3 for all other Ports
+	 */
+	if (type == INTEL_OUTPUT_DSI) {
+		val |= TAP2_DISABLE;
+		val |= TAP3_DISABLE;
+	} else {
+		val &= ~TAP2_DISABLE;
+		val &= ~TAP3_DISABLE;
+	}
+	I915_WRITE(ICL_PORT_TX_DW5_GRP(port), val);
+
+	/* Program PORT_TX_DW2 */
+	val = I915_READ(ICL_PORT_TX_DW2_LN0(port));
+	val &= ~(SWING_SEL_LOWER_MASK | SWING_SEL_UPPER_MASK |
+		 RCOMP_SCALAR_MASK);
+	val |= SWING_SEL_UPPER(ddi_translations[level].dw2_swing_select);
+	val |= SWING_SEL_LOWER(ddi_translations[level].dw2_swing_select);
+	/* Program Rcomp scalar for every table entry */
+	val |= RCOMP_SCALAR(ddi_translations[level].dw2_swing_scalar);
+	I915_WRITE(ICL_PORT_TX_DW2_GRP(port), val);
+
+	/* Program PORT_TX_DW4 */
+	/* We cannot write to GRP. It would overwrite individual loadgen. */
+	for (ln = 0; ln <= 3; ln++) {
+		val = I915_READ(ICL_PORT_TX_DW4_LN(port, ln));
+		val &= ~(POST_CURSOR_1_MASK | POST_CURSOR_2_MASK |
+			 CURSOR_COEFF_MASK);
+		val |= ddi_translations[level].dw4_scaling;
+		I915_WRITE(ICL_PORT_TX_DW4_LN(port, ln), val);
+	}
+}
+
+static void icl_combo_phy_ddi_vswing_sequence(struct intel_encoder *encoder,
+					      u32 level,
+					      enum intel_output_type type)
+{
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	enum port port = encoder->port;
+	int width = 0;
+	int rate = 0;
+	u32 val;
+	int ln = 0;
+
+	if (type == INTEL_OUTPUT_HDMI) {
+		width = 4;
+		/* Rate is always < than 6GHz for HDMI */
+	} else {
+		struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
+
+		width = intel_dp->lane_count;
+		rate = intel_dp->link_rate;
+	}
+
+	/*
+	 * 1. If port type is eDP or DP,
+	 * set PORT_PCS_DW1 cmnkeeper_enable to 1b,
+	 * else clear to 0b.
+	 */
+	val = I915_READ(ICL_PORT_PCS_DW1_LN0(port));
+	if (type == INTEL_OUTPUT_HDMI)
+		val &= ~COMMON_KEEPER_EN;
+	else
+		val |= COMMON_KEEPER_EN;
+	I915_WRITE(ICL_PORT_PCS_DW1_GRP(port), val);
+
+	/* 2. Program loadgen select */
+	/*
+	 * Program PORT_TX_DW4_LN depending on Bit rate and used lanes
+	 * <= 6 GHz and 4 lanes (LN0=0, LN1=1, LN2=1, LN3=1)
+	 * <= 6 GHz and 1,2 lanes (LN0=0, LN1=1, LN2=1, LN3=0)
+	 * > 6 GHz (LN0=0, LN1=0, LN2=0, LN3=0)
+	 */
+	for (ln = 0; ln <= 3; ln++) {
+		val = I915_READ(ICL_PORT_TX_DW4_LN(port, ln));
+		val &= ~LOADGEN_SELECT;
+
+		if ((rate <= 600000 && width == 4 && ln >= 1) ||
+		    (rate <= 600000 && width < 4 && (ln == 1 || ln == 2))) {
+			val |= LOADGEN_SELECT;
+		}
+		I915_WRITE(ICL_PORT_TX_DW4_LN(port, ln), val);
+	}
+
+	/* 3. Set PORT_CL_DW5 SUS Clock Config to 11b */
+	val = I915_READ(ICL_PORT_CL_DW5(port));
+	val |= SUS_CLOCK_CONFIG;
+	I915_WRITE(ICL_PORT_CL_DW5(port), val);
+
+	/* 4. Clear training enable to change swing values */
+	val = I915_READ(ICL_PORT_TX_DW5_LN0(port));
+	val &= ~TX_TRAINING_EN;
+	I915_WRITE(ICL_PORT_TX_DW5_GRP(port), val);
+
+	/* 5. Program swing and de-emphasis */
+	icl_ddi_combo_vswing_program(dev_priv, level, port, type);
+
+	/* 6. Set training enable to trigger update */
+	val = I915_READ(ICL_PORT_TX_DW5_LN0(port));
+	val |= TX_TRAINING_EN;
+	I915_WRITE(ICL_PORT_TX_DW5_GRP(port), val);
+}
+
+static void icl_ddi_vswing_sequence(struct intel_encoder *encoder, u32 level,
+				    enum intel_output_type type)
+{
+	enum port port = encoder->port;
+
+	if (port == PORT_A || port == PORT_B)
+		icl_combo_phy_ddi_vswing_sequence(encoder, level, type);
+	else
+		/* Not Implemented Yet */
+		WARN_ON(1);
+}
+
 static uint32_t translate_signal_level(int signal_levels)
 {
 	int i;
@@ -2213,7 +2392,9 @@ u32 bxt_signal_levels(struct intel_dp *intel_dp)
 	struct intel_encoder *encoder = &dport->base;
 	int level = intel_ddi_dp_level(intel_dp);
 
-	if (IS_CANNONLAKE(dev_priv))
+	if (IS_ICELAKE(dev_priv))
+		icl_ddi_vswing_sequence(encoder, level, encoder->type);
+	else if (IS_CANNONLAKE(dev_priv))
 		cnl_ddi_vswing_sequence(encoder, level, encoder->type);
 	else
 		bxt_ddi_vswing_sequence(encoder, level, encoder->type);
@@ -2316,7 +2497,9 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
 
 	intel_display_power_get(dev_priv, dig_port->ddi_io_power_domain);
 
-	if (IS_CANNONLAKE(dev_priv))
+	if (IS_ICELAKE(dev_priv))
+		icl_ddi_vswing_sequence(encoder, level, encoder->type);
+	else if (IS_CANNONLAKE(dev_priv))
 		cnl_ddi_vswing_sequence(encoder, level, encoder->type);
 	else if (IS_GEN9_LP(dev_priv))
 		bxt_ddi_vswing_sequence(encoder, level, encoder->type);
@@ -2347,7 +2530,9 @@ static void intel_ddi_pre_enable_hdmi(struct intel_encoder *encoder,
 
 	intel_display_power_get(dev_priv, dig_port->ddi_io_power_domain);
 
-	if (IS_CANNONLAKE(dev_priv))
+	if (IS_ICELAKE(dev_priv))
+		icl_ddi_vswing_sequence(encoder, level, INTEL_OUTPUT_HDMI);
+	else if (IS_CANNONLAKE(dev_priv))
 		cnl_ddi_vswing_sequence(encoder, level, INTEL_OUTPUT_HDMI);
 	else if (IS_GEN9_LP(dev_priv))
 		bxt_ddi_vswing_sequence(encoder, level, INTEL_OUTPUT_HDMI);