[PATCH RFC 10/12] drm/i915/display/dp: Adopt dp_connector helpers to expose link training state

[Kory Maincent <kory.maincent@bootlin.com>]

Switch the i915 DP connector initialization from drmm_connector_init()
to drmm_connector_dp_init(), providing the source link capabilities
(supported lane counts, link rates, DSC support, voltage swing and
pre-emphasis levels).

Add intel_dp_report_link_train() to collect the negotiated link
parameters (rate, lane count, DSC enable, per-lane voltage swing and
pre-emphasis) and report them via drm_connector_dp_set_link_train_properties()
once link training completes successfully.

Reset the link training properties via
drm_connector_dp_reset_link_train_properties() when the connector is
reported as disconnected or when the display device is disabled, so
the exposed state always reflects the current link status.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c            | 31 +++++++++++++++++++---
 .../gpu/drm/i915/display/intel_dp_link_training.c  | 25 +++++++++++++++++
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 2af64de9c81de..641406bdc0cc9 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -45,6 +45,7 @@
 #include <drm/display/drm_hdmi_helper.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
+#include <drm/drm_dp_connector.h>
 #include <drm/drm_edid.h>
 #include <drm/drm_fixed.h>
 #include <drm/drm_managed.h>
@@ -6337,8 +6338,10 @@ intel_dp_detect(struct drm_connector *_connector,
 	drm_WARN_ON(display->drm,
 		    !drm_modeset_is_locked(&display->drm->mode_config.connection_mutex));
 
-	if (!intel_display_device_enabled(display))
+	if (!intel_display_device_enabled(display)) {
+		drm_connector_dp_reset_link_train_properties(_connector);
 		return connector_status_disconnected;
+	}
 
 	if (!intel_display_driver_check_access(display))
 		return connector->base.status;
@@ -6388,6 +6391,8 @@ intel_dp_detect(struct drm_connector *_connector,
 
 		intel_dp_tunnel_disconnect(intel_dp);
 
+		drm_connector_dp_reset_link_train_properties(_connector);
+
 		goto out_unset_edid;
 	}
 
@@ -7162,10 +7167,12 @@ intel_dp_init_connector(struct intel_digital_port *dig_port,
 			struct intel_connector *connector)
 {
 	struct intel_display *display = to_intel_display(dig_port);
+	struct drm_connector_dp_link_train_caps link_caps;
 	struct intel_dp *intel_dp = &dig_port->dp;
 	struct intel_encoder *encoder = &dig_port->base;
 	struct drm_device *dev = encoder->base.dev;
 	enum port port = encoder->port;
+	u32 *rates;
 	int type;
 
 	if (drm_WARN(dev, dig_port->max_lanes < 1,
@@ -7213,8 +7220,25 @@ intel_dp_init_connector(struct intel_digital_port *dig_port,
 		    type == DRM_MODE_CONNECTOR_eDP ? "eDP" : "DP",
 		    encoder->base.base.id, encoder->base.name);
 
-	drmm_connector_init(dev, &connector->base, &intel_dp_connector_funcs,
-			    type, &intel_dp->aux.ddc);
+	intel_dp_set_source_rates(intel_dp);
+	link_caps.nlanes = DRM_DP_1LANE | DRM_DP_2LANE | DRM_DP_4LANE;
+	link_caps.nrates = intel_dp->num_source_rates;
+	rates = kzalloc_objs(*rates, intel_dp->num_source_rates);
+	if (!rates)
+		goto fail;
+
+	for (int i = 0; i < intel_dp->num_source_rates; i++)
+		rates[i] = intel_dp->source_rates[i];
+
+	link_caps.rates = rates;
+	link_caps.dsc = true;
+	link_caps.v_swings = DRM_DP_VOLTAGE_SWING_LEVEL_MASK;
+	link_caps.pre_emphs = DRM_DP_PRE_EMPH_LEVEL_MASK;
+
+	drmm_connector_dp_init(dev, &connector->base, &intel_dp_connector_funcs,
+			       &link_caps, type, &intel_dp->aux.ddc);
+	kfree(rates);
+
 	drm_connector_helper_add(&connector->base, &intel_dp_connector_helper_funcs);
 
 	if (drmm_add_action_or_reset(dev, intel_connector_destroy, connector)) {
@@ -7240,7 +7264,6 @@ intel_dp_init_connector(struct intel_digital_port *dig_port,
 	if (!intel_edp_init_connector(intel_dp, connector))
 		goto fail;
 
-	intel_dp_set_source_rates(intel_dp);
 	intel_dp_set_common_rates(intel_dp);
 	intel_dp_reset_link_params(intel_dp);
 
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 54c585c59b900..c2fd46a323650 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -25,6 +25,7 @@
 #include <linux/iopoll.h>
 
 #include <drm/display/drm_dp_helper.h>
+#include <drm/drm_dp_connector.h>
 #include <drm/drm_print.h>
 
 #include "intel_display_core.h"
@@ -1116,6 +1117,27 @@ intel_dp_128b132b_intra_hop(struct intel_dp *intel_dp,
 	return sink_status & DP_INTRA_HOP_AUX_REPLY_INDICATION ? 1 : 0;
 }
 
+static void intel_dp_report_link_train(struct intel_dp *intel_dp)
+{
+	struct intel_connector *connector = intel_dp->attached_connector;
+	struct drm_connector_dp_link_train dp_link_train;
+
+	dp_link_train.rate = intel_dp->link_rate;
+	dp_link_train.nlanes = intel_dp->lane_count;
+	dp_link_train.dsc_en = connector->dp.dsc_decompression_enabled;
+
+	for (int i = 0; i < intel_dp->lane_count; i++) {
+		int v_swing_level = (intel_dp->train_set[i] &
+				     DP_TRAIN_VOLTAGE_SWING_MASK) >> DP_TRAIN_VOLTAGE_SWING_SHIFT;
+		int pre_emph_level = (intel_dp->train_set[i] &
+				      DP_TRAIN_PRE_EMPHASIS_MASK) >> DP_TRAIN_PRE_EMPHASIS_SHIFT;
+		dp_link_train.v_swing[i] = 1 << v_swing_level;
+		dp_link_train.pre_emph[i] = 1 << pre_emph_level;
+	}
+
+	drm_connector_dp_set_link_train_properties(&connector->base, &dp_link_train);
+}
+
 /**
  * intel_dp_stop_link_train - stop link training
  * @intel_dp: DP struct
@@ -1144,6 +1166,9 @@ void intel_dp_stop_link_train(struct intel_dp *intel_dp,
 	intel_dp_program_link_training_pattern(intel_dp, crtc_state, DP_PHY_DPRX,
 					       DP_TRAINING_PATTERN_DISABLE);
 
+	if (!intel_dp->is_mst)
+		intel_dp_report_link_train(intel_dp);
+
 	if (intel_dp_is_uhbr(crtc_state)) {
 		ret = poll_timeout_us(ret = intel_dp_128b132b_intra_hop(intel_dp, crtc_state),
 				      ret == 0,

-- 
2.43.0