drm/i915/dsc: Enable and disable appropriate power wells for VDSC

A separate power well 2 (PG2) is required for VDSC on eDP transcoder
whereas all other transcoders use the power wells associated with the
transcoders for VDSC.
This patch adds a helper to obtain correct power domain depending on
transcoder being used and enables/disables the power wells during
VDSC enabling/disabling.

v4:
* Get VDSC power domain only if compression en is set
in crtc_state (Ville, Imre)
v3:
* Call it intel_dsc_power_domain, add to
intel_ddi_get_power_domains (Ville)
v2:
* Fix tabs, const crtc_state, fix comments (Ville)
Suggested-by: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181128202628.20238-13-manasi.d.navare@intel.com

drivers/gpu/drm/i915/intel_ddi.c

@@ -2154,6 +2154,12 @@ static u64 intel_ddi_get_power_domains(struct intel_encoder *encoder,
 	    intel_port_is_tc(dev_priv, encoder->port))
 		domains |= BIT_ULL(intel_ddi_main_link_aux_domain(dig_port));
 
+	/*
+	 * VDSC power is needed when DSC is enabled
+	 */
+	if (crtc_state->dsc_params.compression_enable)
+		domains |= BIT_ULL(intel_dsc_power_domain(crtc_state));
+
 	return domains;
 }
 

drivers/gpu/drm/i915/intel_drv.h

@@ -1863,6 +1863,8 @@ uint8_t intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp, int mode_clock,
 /* intel_vdsc.c */
 int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
 				struct intel_crtc_state *pipe_config);
+enum intel_display_power_domain
+intel_dsc_power_domain(const struct intel_crtc_state *crtc_state);
 
 static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
 {

drivers/gpu/drm/i915/intel_vdsc.c

@@ -578,6 +578,24 @@ int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
 	return intel_compute_rc_parameters(vdsc_cfg);
 }
 
+enum intel_display_power_domain
+intel_dsc_power_domain(const struct intel_crtc_state *crtc_state)
+{
+	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
+
+	/*
+	 * On ICL VDSC/joining for eDP transcoder uses a separate power well PW2
+	 * This requires POWER_DOMAIN_TRANSCODER_EDP_VDSC power domain.
+	 * For any other transcoder, VDSC/joining uses the power well associated
+	 * with the pipe/transcoder in use. Hence another reference on the
+	 * transcoder power domain will suffice.
+	 */
+	if (cpu_transcoder == TRANSCODER_EDP)
+		return POWER_DOMAIN_TRANSCODER_EDP_VDSC;
+	else
+		return POWER_DOMAIN_TRANSCODER(cpu_transcoder);
+}
+
 static void intel_configure_pps_for_dsc_encoder(struct intel_encoder *encoder,
 						const struct intel_crtc_state *crtc_state)
 {
@@ -1010,6 +1028,10 @@ void intel_dsc_enable(struct intel_encoder *encoder,
 	if (!crtc_state->dsc_params.compression_enable)
 		return;
 
+	/* Enable Power wells for VDSC/joining */
+	intel_display_power_get(dev_priv,
+				intel_dsc_power_domain(crtc_state));
+
 	intel_configure_pps_for_dsc_encoder(encoder, crtc_state);
 
 	intel_dp_write_dsc_pps_sdp(encoder, crtc_state);
@@ -1059,4 +1081,8 @@ void intel_dsc_disable(const struct intel_crtc_state *old_crtc_state)
 		dss_ctl2_val &= ~(LEFT_BRANCH_VDSC_ENABLE |
 				  RIGHT_BRANCH_VDSC_ENABLE);
 	I915_WRITE(dss_ctl2_reg, dss_ctl2_val);
+
+	/* Disable Power wells for VDSC/joining */
+	intel_display_power_put(dev_priv,
+				intel_dsc_power_domain(old_crtc_state));
 }