[PATCH RFC v2 2/4] 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
drm_connector_init_with_ddc() to drm_connector_dp_init_with_ddc(),
providing the source link capabilities (supported lane counts, link rates
and DSC support).

Add intel_dp_report_link_train() to collect the negotiated link
parameters (rate, lane count and DSC enable) and report them via
drm_dp_set_max_link_params() and drm_dp_set_cur_link_params() once
link training completes successfully.

Reset the link properties via drm_dp_reset_link_params()
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>
---

Changes in v2:
- Remove voltage swing and pre emphasis properties.
---
 drivers/gpu/drm/i915/display/intel_dp.c            | 26 ++++++++++++++++++----
 .../gpu/drm/i915/display/intel_dp_link_training.c  | 17 ++++++++++++++
 2 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index f01a6eed38395..46c06c76952e0 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -6414,8 +6414,10 @@ 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_dp_sink_reset_link_caps(_connector);
 		return connector_status_disconnected;
+	}
 
 	if (!intel_display_driver_check_access(display))
 		return connector->base.status;
@@ -6465,6 +6467,8 @@ intel_dp_detect(struct drm_connector *_connector,
 
 		intel_dp_tunnel_disconnect(intel_dp);
 
+		drm_dp_sink_reset_link_caps(_connector);
+
 		goto out_unset_edid;
 	}
 
@@ -7240,10 +7244,12 @@ 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_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,
@@ -7291,8 +7297,21 @@ intel_dp_init_connector(struct intel_digital_port *dig_port,
 		    type == DRM_MODE_CONNECTOR_eDP ? "eDP" : "DP",
 		    encoder->base.base.id, encoder->base.name);
 
-	drm_connector_init_with_ddc(dev, &connector->base, &intel_dp_connector_funcs,
-				    type, &intel_dp->aux.ddc);
+	intel_dp_set_source_rates(intel_dp);
+	link_caps.nlanes = 4;
+	link_caps.nlink_rates = intel_dp->num_source_rates;
+	rates = kmemdup_array(intel_dp->source_rates, intel_dp->num_source_rates,
+			      sizeof(*rates), GFP_KERNEL);
+	if (!rates)
+		goto fail;
+
+	link_caps.link_rates = rates;
+	link_caps.dsc = HAS_DSC(display);
+
+	drm_connector_dp_init_with_ddc(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 (!HAS_GMCH(display) && DISPLAY_VER(display) < 12)
@@ -7315,7 +7334,6 @@ intel_dp_init_connector(struct intel_digital_port *dig_port,
 		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 a26094223f780..25e0e957fe36d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -1231,6 +1231,18 @@ 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;
+
+	drm_dp_set_max_link_params(&connector->base, intel_dp->link_rate,
+				   intel_dp->lane_count);
+
+	drm_dp_set_cur_link_params(&connector->base, intel_dp->link_rate,
+				   intel_dp->lane_count,
+				   connector->dp.dsc_decompression_enabled);
+}
+
 /**
  * intel_dp_stop_link_train - stop link training
  * @intel_dp: DP struct
@@ -1259,6 +1271,9 @@ 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,
@@ -1772,6 +1787,8 @@ void intel_dp_start_link_train(struct intel_atomic_state *state,
 	 */
 	int lttpr_count;
 
+	drm_dp_sink_set_link_caps(&intel_dp->attached_connector->base, &intel_dp->aux);
+
 	intel_hpd_block(encoder);
 
 	lttpr_count = intel_dp_init_lttpr_and_dprx_caps(intel_dp);

-- 
2.43.0