[PATCH 16/22] drm/i915: Introduce struct intel_dp_signal_levels

[Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>]

In order to clarify which platforms support which combination of voltage
swing and pre emphasis level, introduce struct intel_dp_signal_levels.
With the new struct, the if ladder to determine the values used is put
in one place, intel_dp_init_signal_levels().

This also wires gens 4, 5 and non-eDP ports on gen 6 and 7 to use the
new struct.

v2: Rebase
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c               |   2 +
 drivers/gpu/drm/i915/intel_dp_signal_levels.c | 103 ++++++++++++++++++++++----
 drivers/gpu/drm/i915/intel_drv.h              |  11 +++
 3 files changed, 101 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 1236791..e640b59 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5220,6 +5220,8 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 	if (HAS_DDI(dev))
 		intel_dp->prepare_link_retrain = intel_ddi_prepare_link_retrain;
 
+	intel_dp_init_signal_levels(intel_dp);
+
 	/* Preserve the current hw state. */
 	intel_dp->DP = I915_READ(intel_dp->output_reg);
 	intel_dp->attached_connector = intel_connector;
diff --git a/drivers/gpu/drm/i915/intel_dp_signal_levels.c b/drivers/gpu/drm/i915/intel_dp_signal_levels.c
index e516dd2..365bdc4 100644
--- a/drivers/gpu/drm/i915/intel_dp_signal_levels.c
+++ b/drivers/gpu/drm/i915/intel_dp_signal_levels.c
@@ -24,8 +24,8 @@
 #include "intel_drv.h"
 
 /* These are source-specific values. */
-uint8_t
-intel_dp_voltage_max(struct intel_dp *intel_dp)
+static uint8_t
+_dp_voltage_max(struct intel_dp *intel_dp)
 {
 	struct drm_device *dev = intel_dp_to_dev(intel_dp);
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -47,8 +47,8 @@ intel_dp_voltage_max(struct intel_dp *intel_dp)
 		return DP_TRAIN_VOLTAGE_SWING_LEVEL_2;
 }
 
-uint8_t
-intel_dp_pre_emphasis_max(struct intel_dp *intel_dp, uint8_t voltage_swing)
+static uint8_t
+_dp_pre_emphasis_max(struct intel_dp *intel_dp, uint8_t voltage_swing)
 {
 	struct drm_device *dev = intel_dp_to_dev(intel_dp);
 	enum port port = dp_to_dig_port(intel_dp)->port;
@@ -389,10 +389,10 @@ static uint32_t chv_signal_levels(struct intel_dp *intel_dp)
 	return 0;
 }
 
-static uint32_t
-gen4_signal_levels(uint8_t train_set)
+static void
+gen4_set_signal_levels(struct intel_dp *intel_dp, uint8_t train_set)
 {
-	uint32_t	signal_levels = 0;
+	uint32_t signal_levels = 0;
 
 	switch (train_set & DP_TRAIN_VOLTAGE_SWING_MASK) {
 	case DP_TRAIN_VOLTAGE_SWING_LEVEL_0:
@@ -424,9 +424,38 @@ gen4_signal_levels(uint8_t train_set)
 		signal_levels |= DP_PRE_EMPHASIS_9_5;
 		break;
 	}
-	return signal_levels;
+
+	DRM_DEBUG_KMS("Using signal levels %08x\n", signal_levels);
+
+	intel_dp->DP &= ~(DP_VOLTAGE_MASK | DP_PRE_EMPHASIS_MASK);
+	intel_dp->DP |= signal_levels;
 }
 
+static const struct signal_levels gen4_signal_levels = {
+	.max_voltage = DP_TRAIN_VOLTAGE_SWING_LEVEL_2,
+	.max_pre_emph = {
+		DP_TRAIN_PRE_EMPH_LEVEL_2,
+		DP_TRAIN_PRE_EMPH_LEVEL_2,
+		DP_TRAIN_PRE_EMPH_LEVEL_1,
+		DP_TRAIN_PRE_EMPH_LEVEL_0,
+	},
+
+	.set = gen4_set_signal_levels,
+};
+
+/* Not for eDP */
+static const struct signal_levels snb_signal_levels = {
+	.max_voltage = DP_TRAIN_VOLTAGE_SWING_LEVEL_3,
+	.max_pre_emph = {
+		DP_TRAIN_PRE_EMPH_LEVEL_2,
+		DP_TRAIN_PRE_EMPH_LEVEL_2,
+		DP_TRAIN_PRE_EMPH_LEVEL_1,
+		DP_TRAIN_PRE_EMPH_LEVEL_0,
+	},
+
+	.set = gen4_set_signal_levels,
+};
+
 /* Gen6's DP voltage swing and pre-emphasis control */
 static uint32_t
 gen6_edp_signal_levels(uint8_t train_set)
@@ -486,13 +515,12 @@ gen7_edp_signal_levels(uint8_t train_set)
 	}
 }
 
-void
-intel_dp_set_signal_levels(struct intel_dp *intel_dp)
+static void
+_update_signal_levels(struct intel_dp *intel_dp)
 {
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
 	enum port port = intel_dig_port->port;
 	struct drm_device *dev = intel_dig_port->base.base.dev;
-	struct drm_i915_private *dev_priv = to_i915(dev);
 	uint32_t signal_levels, mask = 0;
 	uint8_t train_set = intel_dp->train_set[0];
 
@@ -514,21 +542,66 @@ intel_dp_set_signal_levels(struct intel_dp *intel_dp)
 		signal_levels = gen6_edp_signal_levels(train_set);
 		mask = EDP_LINK_TRAIN_VOL_EMP_MASK_SNB;
 	} else {
-		signal_levels = gen4_signal_levels(train_set);
-		mask = DP_VOLTAGE_MASK | DP_PRE_EMPHASIS_MASK;
+		WARN(1, "Should be calling intel_dp->signal_levels->set instead.");
+		return;
 	}
 
 	if (mask)
 		DRM_DEBUG_KMS("Using signal levels %08x\n", signal_levels);
 
+	intel_dp->DP = (intel_dp->DP & ~mask) | signal_levels;
+}
+
+uint8_t
+intel_dp_voltage_max(struct intel_dp *intel_dp)
+{
+	if (intel_dp->signal_levels)
+		return intel_dp->signal_levels->max_voltage;
+	else
+		return _dp_voltage_max(intel_dp);
+}
+
+uint8_t
+intel_dp_pre_emphasis_max(struct intel_dp *intel_dp, uint8_t voltage_swing)
+{
+	if (intel_dp->signal_levels)
+		return intel_dp->signal_levels->max_pre_emph[voltage_swing];
+	else
+		return _dp_pre_emphasis_max(intel_dp, voltage_swing);
+}
+
+void
+intel_dp_set_signal_levels(struct intel_dp *intel_dp)
+{
+	struct drm_device *dev = intel_dp_to_dev(intel_dp);
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	uint8_t train_set = intel_dp->train_set[0];
+
+	if (intel_dp->signal_levels)
+		intel_dp->signal_levels->set(intel_dp, train_set);
+	else
+		_update_signal_levels(intel_dp);
+
 	DRM_DEBUG_KMS("Using vswing level %d\n",
 		train_set & DP_TRAIN_VOLTAGE_SWING_MASK);
 	DRM_DEBUG_KMS("Using pre-emphasis level %d\n",
 		(train_set & DP_TRAIN_PRE_EMPHASIS_MASK) >>
 			DP_TRAIN_PRE_EMPHASIS_SHIFT);
 
-	intel_dp->DP = (intel_dp->DP & ~mask) | signal_levels;
-
 	I915_WRITE(intel_dp->output_reg, intel_dp->DP);
 	POSTING_READ(intel_dp->output_reg);
 }
+
+void
+intel_dp_init_signal_levels(struct intel_dp *intel_dp)
+{
+	struct drm_device *dev = intel_dp_to_dev(intel_dp);
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	enum port port = intel_dig_port->port;
+
+	if (port != PORT_A && (IS_IVYBRIDGE(dev) || IS_GEN6(dev)))
+		intel_dp->signal_levels = &snb_signal_levels;
+
+	if (INTEL_INFO(dev)->gen <= 5)
+		intel_dp->signal_levels = &gen4_signal_levels;
+}
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index d758e94..e00ce6c 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -726,6 +726,14 @@ struct sink_crc {
 	int last_count;
 };
 
+struct intel_dp;
+struct signal_levels {
+	uint8_t max_voltage;
+	uint8_t max_pre_emph[4];
+
+	void (*set)(struct intel_dp *intel_dp, uint8_t train_set);
+};
+
 struct intel_dp {
 	uint32_t output_reg;
 	uint32_t aux_ch_ctl_reg;
@@ -744,6 +752,7 @@ struct intel_dp {
 	int sink_rates[DP_MAX_SUPPORTED_RATES];
 	struct sink_crc sink_crc;
 	struct drm_dp_aux aux;
+	const struct signal_levels *signal_levels;
 	uint8_t train_set[4];
 	int panel_power_up_delay;
 	int panel_power_down_delay;
@@ -1263,6 +1272,8 @@ bool intel_dp_source_supports_hbr2(struct intel_dp *intel_dp);
 bool
 intel_dp_get_link_status(struct intel_dp *intel_dp, uint8_t link_status[DP_LINK_STATUS_SIZE]);
 
+void intel_dp_init_signal_levels(struct intel_dp *intel_dp);
+
 /* intel_dp_mst.c */
 int intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_id);
 void intel_dp_mst_encoder_cleanup(struct intel_digital_port *intel_dig_port);
-- 
2.4.3

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