drm/i915/dp: Disable DSC in source by disabling DSS CTL bits

1. Disable Left/right VDSC branch in DSS Ctrl reg
    depending on the number of VDSC engines being used
2. Disable joiner in DSS Ctrl reg

v4:
* Remove encoder, make crtc_state const (Ville)
v3 (From Manasi):
* Add Disable PG2 for VDSC on eDP
v2 (From Manasi):
* Use old_crtc_state to find dsc params
* Add a condition to disable only if
dsc state compression is enabled
* Use correct DSS CTL regs

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181128202628.20238-12-manasi.d.navare@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -3342,6 +3342,7 @@ extern bool intel_set_memory_cxsr(struct drm_i915_private *dev_priv,
 				  bool enable);
 void intel_dsc_enable(struct intel_encoder *encoder,
 		      const struct intel_crtc_state *crtc_state);
+void intel_dsc_disable(const struct intel_crtc_state *crtc_state);
 
 int i915_reg_read_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file);

drivers/gpu/drm/i915/intel_display.c

@@ -5923,6 +5923,8 @@ static void haswell_crtc_disable(struct intel_crtc_state *old_crtc_state,
 	if (!transcoder_is_dsi(cpu_transcoder))
 		intel_ddi_disable_transcoder_func(old_crtc_state);
 
+	intel_dsc_disable(old_crtc_state);
+
 	if (INTEL_GEN(dev_priv) >= 9)
 		skylake_scaler_disable(intel_crtc);
 	else

drivers/gpu/drm/i915/intel_vdsc.c

@@ -1029,3 +1029,34 @@ void intel_dsc_enable(struct intel_encoder *encoder,
 	I915_WRITE(dss_ctl1_reg, dss_ctl1_val);
 	I915_WRITE(dss_ctl2_reg, dss_ctl2_val);
 }
+
+void intel_dsc_disable(const struct intel_crtc_state *old_crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->base.crtc);
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	enum pipe pipe = crtc->pipe;
+	i915_reg_t dss_ctl1_reg, dss_ctl2_reg;
+	u32 dss_ctl1_val = 0, dss_ctl2_val = 0;
+
+	if (!old_crtc_state->dsc_params.compression_enable)
+		return;
+
+	if (old_crtc_state->cpu_transcoder == TRANSCODER_EDP) {
+		dss_ctl1_reg = DSS_CTL1;
+		dss_ctl2_reg = DSS_CTL2;
+	} else {
+		dss_ctl1_reg = ICL_PIPE_DSS_CTL1(pipe);
+		dss_ctl2_reg = ICL_PIPE_DSS_CTL2(pipe);
+	}
+	dss_ctl1_val = I915_READ(dss_ctl1_reg);
+	if (dss_ctl1_val & JOINER_ENABLE)
+		dss_ctl1_val &= ~JOINER_ENABLE;
+	I915_WRITE(dss_ctl1_reg, dss_ctl1_val);
+
+	dss_ctl2_val = I915_READ(dss_ctl2_reg);
+	if (dss_ctl2_val & LEFT_BRANCH_VDSC_ENABLE ||
+	    dss_ctl2_val & RIGHT_BRANCH_VDSC_ENABLE)
+		dss_ctl2_val &= ~(LEFT_BRANCH_VDSC_ENABLE |
+				  RIGHT_BRANCH_VDSC_ENABLE);
+	I915_WRITE(dss_ctl2_reg, dss_ctl2_val);
+}