drm/i915: Create intel_dp->prepare_link_retrain() hook

In order to prepare for a link training with DDI, the state machine
would call intel_ddi_prepare_link_retrain(). To remove the dependency to
the hardware information, replace that direct call with a callback.
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1445594525-7174-7-git-send-email-ander.conselvan.de.oliveira@intel.com

drivers/gpu/drm/i915/intel_ddi.c

@@ -2971,11 +2971,11 @@ void intel_ddi_pll_init(struct drm_device *dev)
 	}
 }
 
-void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder)
+void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
 {
-	struct intel_digital_port *intel_dig_port = enc_to_dig_port(encoder);
-	struct intel_dp *intel_dp = &intel_dig_port->dp;
-	struct drm_i915_private *dev_priv = encoder->dev->dev_private;
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	struct drm_i915_private *dev_priv =
+		to_i915(intel_dig_port->base.base.dev);
 	enum port port = intel_dig_port->port;
 	uint32_t val;
 	bool wait = false;

drivers/gpu/drm/i915/intel_dp.c

@@ -5731,6 +5731,9 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 	else
 		intel_dp->get_aux_send_ctl = i9xx_get_aux_send_ctl;
 
+	if (HAS_DDI(dev))
+		intel_dp->prepare_link_retrain = intel_ddi_prepare_link_retrain;
+
 	/* Preserve the current hw state. */
 	intel_dp->DP = I915_READ(intel_dp->output_reg);
 	intel_dp->attached_connector = intel_connector;

drivers/gpu/drm/i915/intel_dp_link_training.c

@@ -108,16 +108,14 @@ intel_dp_update_link_train(struct intel_dp *intel_dp)
 static void
 intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
 {
-	struct drm_encoder *encoder = &dp_to_dig_port(intel_dp)->base.base;
-	struct drm_device *dev = encoder->dev;
 	int i;
 	uint8_t voltage;
 	int voltage_tries, loop_tries;
 	uint8_t link_config[2];
 	uint8_t link_bw, rate_select;
 
-	if (HAS_DDI(dev))
-		intel_ddi_prepare_link_retrain(encoder);
+	if (intel_dp->prepare_link_retrain)
+		intel_dp->prepare_link_retrain(intel_dp);
 
 	intel_dp_compute_rate(intel_dp, intel_dp->link_rate,
 			      &link_bw, &rate_select);

drivers/gpu/drm/i915/intel_drv.h

@@ -802,6 +802,10 @@ struct intel_dp {
 				     bool has_aux_irq,
 				     int send_bytes,
 				     uint32_t aux_clock_divider);
+
+	/* This is called before a link training is starterd */
+	void (*prepare_link_retrain)(struct intel_dp *intel_dp);
+
 	bool train_set_valid;
 
 	/* Displayport compliance testing */
@@ -1006,7 +1010,7 @@ void intel_ddi_disable_pipe_clock(struct intel_crtc *intel_crtc);
 bool intel_ddi_pll_select(struct intel_crtc *crtc,
 			  struct intel_crtc_state *crtc_state);
 void intel_ddi_set_pipe_settings(struct drm_crtc *crtc);
-void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder);
+void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp);
 bool intel_ddi_connector_get_hw_state(struct intel_connector *intel_connector);
 void intel_ddi_fdi_disable(struct drm_crtc *crtc);
 void intel_ddi_get_config(struct intel_encoder *encoder,