drm/i915/display: Load DP_TP_CTL/STATUS offset before use it

Right now dp.regs.dp_tp_ctl/status are only set during the encoder
pre_enable() hook, what is causing all reads and writes to those
registers to go to offset 0x0 before pre_enable() is executed.

So if i915 takes the BIOS state and don't do a modeset any following
link retraing will fail.

In the case that i915 needs to do a modeset, the DDI disable sequence
will write to a wrong register not disabling DP 'Transport Enable' in
DP_TP_CTL, making a HDMI modeset in the same port/transcoder to
not light up the monitor.

So here for GENs older than 12, that have those registers fixed at
port offset range it is loading at encoder/port init while for GEN12
it will keep setting it at encoder pre_enable() and during HW state
readout.

Fixes: 4444df6e ("drm/i915/tgl: move DP_TP_* to transcoder")
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200414230442.262092-1-jose.souza@intel.com
(cherry picked from commit edcb9028)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -3141,9 +3141,6 @@ static void hsw_ddi_pre_enable_dp(struct intel_encoder *encoder,
 	intel_dp_set_link_params(intel_dp, crtc_state->port_clock,
 				 crtc_state->lane_count, is_mst);
 
-	intel_dp->regs.dp_tp_ctl = DP_TP_CTL(port);
-	intel_dp->regs.dp_tp_status = DP_TP_STATUS(port);
-
 	intel_edp_panel_on(intel_dp);
 
 	intel_ddi_clk_select(encoder, crtc_state);
@@ -3848,12 +3845,18 @@ void intel_ddi_get_config(struct intel_encoder *encoder,
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_crtc *intel_crtc = to_intel_crtc(pipe_config->uapi.crtc);
 	enum transcoder cpu_transcoder = pipe_config->cpu_transcoder;
+	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
 	u32 temp, flags = 0;
 
 	/* XXX: DSI transcoder paranoia */
 	if (drm_WARN_ON(&dev_priv->drm, transcoder_is_dsi(cpu_transcoder)))
 		return;
 
+	if (INTEL_GEN(dev_priv) >= 12) {
+		intel_dp->regs.dp_tp_ctl = TGL_DP_TP_CTL(cpu_transcoder);
+		intel_dp->regs.dp_tp_status = TGL_DP_TP_STATUS(cpu_transcoder);
+	}
+
 	intel_dsc_get_config(encoder, pipe_config);
 
 	temp = intel_de_read(dev_priv, TRANS_DDI_FUNC_CTL(cpu_transcoder));
@@ -4173,6 +4176,7 @@ static const struct drm_encoder_funcs intel_ddi_funcs = {
 static struct intel_connector *
 intel_ddi_init_dp_connector(struct intel_digital_port *intel_dig_port)
 {
+	struct drm_i915_private *dev_priv = to_i915(intel_dig_port->base.base.dev);
 	struct intel_connector *connector;
 	enum port port = intel_dig_port->base.port;
 
@@ -4183,6 +4187,10 @@ intel_ddi_init_dp_connector(struct intel_digital_port *intel_dig_port)
 	intel_dig_port->dp.output_reg = DDI_BUF_CTL(port);
 	intel_dig_port->dp.prepare_link_retrain =
 		intel_ddi_prepare_link_retrain;
+	if (INTEL_GEN(dev_priv) < 12) {
+		intel_dig_port->dp.regs.dp_tp_ctl = DP_TP_CTL(port);
+		intel_dig_port->dp.regs.dp_tp_status = DP_TP_STATUS(port);
+	}
 
 	if (!intel_dp_init_connector(intel_dig_port, connector)) {
 		kfree(connector);

drivers/gpu/drm/i915/display/intel_dp.c

@@ -2517,9 +2517,6 @@ static void intel_dp_prepare(struct intel_encoder *encoder,
 				 intel_crtc_has_type(pipe_config,
 						     INTEL_OUTPUT_DP_MST));
 
-	intel_dp->regs.dp_tp_ctl = DP_TP_CTL(port);
-	intel_dp->regs.dp_tp_status = DP_TP_STATUS(port);
-
 	/*
 	 * There are four kinds of DP registers:
 	 *
@@ -7836,6 +7833,8 @@ bool intel_dp_init(struct drm_i915_private *dev_priv,
 
 	intel_dig_port->dp.output_reg = output_reg;
 	intel_dig_port->max_lanes = 4;
+	intel_dig_port->dp.regs.dp_tp_ctl = DP_TP_CTL(port);
+	intel_dig_port->dp.regs.dp_tp_status = DP_TP_STATUS(port);
 
 	intel_encoder->type = INTEL_OUTPUT_DP;
 	intel_encoder->power_domain = intel_port_to_power_domain(port);