[Intel-gfx] [PATCH] drm/i915/tgl: Do not read the transcoder register for mipi dsi

[Vandita Kulkarni]

As per the Bspec the port mapping is fixed for mipi dsi

Signed-off-by: Vandita Kulkarni <vandita.kulkarni at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 27 ++++++++++++++++----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index f1328c08f4ad..d4a8617d6185 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -10397,21 +10397,38 @@ static bool bxt_get_dsi_transcoder_state(struct intel_crtc *crtc,
 	return transcoder_is_dsi(pipe_config->cpu_transcoder);
 }
 
-static void haswell_get_ddi_port_state(struct intel_crtc *crtc,
-				       struct intel_crtc_state *pipe_config)
+static enum port
+intel_transcoder_to_port(struct drm_i915_private *dev_priv,
+			  enum transcoder cpu_transcoder)
 {
-	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	struct intel_shared_dpll *pll;
 	enum port port;
 	u32 tmp;
 
-	tmp = I915_READ(TRANS_DDI_FUNC_CTL(pipe_config->cpu_transcoder));
+	/* DSI transcoders have fixed ddi mapping*/
+	if (transcoder_is_dsi(cpu_transcoder)) {
+		port = (cpu_transcoder == TRANSCODER_DSI_A) ? PORT_A : PORT_B;
+		return port;
+	}
 
+	tmp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
 	if (INTEL_GEN(dev_priv) >= 12)
 		port = TGL_TRANS_DDI_FUNC_CTL_VAL_TO_PORT(tmp);
 	else
 		port = TRANS_DDI_FUNC_CTL_VAL_TO_PORT(tmp);
 
+	return port;
+}
+
+static void haswell_get_ddi_port_state(struct intel_crtc *crtc,
+				       struct intel_crtc_state *pipe_config)
+{
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	struct intel_shared_dpll *pll;
+	enum port port;
+	u32 tmp;
+
+	port = intel_transcoder_to_port(dev_priv, pipe_config->cpu_transcoder);
+
 	if (INTEL_GEN(dev_priv) >= 11)
 		icelake_get_ddi_pll(dev_priv, port, pipe_config);
 	else if (IS_CANNONLAKE(dev_priv))
-- 
2.21.0.5.gaeb582a