drm/i915/dsc: Add helper for writing DSC Selective Update ET parameters

There are slice row per frame and pic height configuration in DSC Selective
Update Parameter Set 1 register. Add helper for configuring these.

v2:
  - Add WARN_ON_ONCE if vdsc instances per pipe > 2
  - instead of checking vdsc instances per pipe being > 1 check == 2

Bspec: 71709
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patch.msgid.link/20260304113011.626542-4-jouni.hogander@intel.com
(cherry picked from commit c8698d6)
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>
[tursulin: fixup forward declaration conflict]

Author: hogander

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

@@ -767,6 +767,29 @@ void intel_dsc_dp_pps_write(struct intel_encoder *encoder,
 				  sizeof(dp_dsc_pps_sdp));
 }
 
+void intel_dsc_su_et_parameters_configure(struct intel_dsb *dsb, struct intel_encoder *encoder,
+					  const struct intel_crtc_state *crtc_state, int su_lines)
+{
+	struct intel_display *display = to_intel_display(crtc_state);
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	const struct drm_dsc_config *vdsc_cfg = &crtc_state->dsc.config;
+	enum pipe pipe = crtc->pipe;
+	int vdsc_instances_per_pipe = intel_dsc_get_vdsc_per_pipe(crtc_state);
+	int slice_row_per_frame = su_lines / vdsc_cfg->slice_height;
+	u32 val;
+
+	drm_WARN_ON_ONCE(display->drm, su_lines % vdsc_cfg->slice_height);
+	drm_WARN_ON_ONCE(display->drm, vdsc_instances_per_pipe > 2);
+
+	val = DSC_SUPS0_SU_SLICE_ROW_PER_FRAME(slice_row_per_frame);
+	val |= DSC_SUPS0_SU_PIC_HEIGHT(su_lines);
+
+	intel_de_write_dsb(display, dsb, LNL_DSC0_SU_PARAMETER_SET_0(pipe), val);
+
+	if (vdsc_instances_per_pipe == 2)
+		intel_de_write_dsb(display, dsb, LNL_DSC1_SU_PARAMETER_SET_0(pipe), val);
+}
+
 static i915_reg_t dss_ctl1_reg(struct intel_crtc *crtc, enum transcoder cpu_transcoder)
 {
 	return is_pipe_dsc(crtc, cpu_transcoder) ?

drivers/gpu/drm/i915/display/intel_vdsc.h

@@ -13,6 +13,7 @@ struct drm_printer;
 enum transcoder;
 struct intel_crtc;
 struct intel_crtc_state;
+struct intel_dsb;
 struct intel_encoder;
 
 bool intel_dsc_source_support(const struct intel_crtc_state *crtc_state);
@@ -31,6 +32,8 @@ void intel_dsc_dsi_pps_write(struct intel_encoder *encoder,
 			     const struct intel_crtc_state *crtc_state);
 void intel_dsc_dp_pps_write(struct intel_encoder *encoder,
 			    const struct intel_crtc_state *crtc_state);
+void intel_dsc_su_et_parameters_configure(struct intel_dsb *dsb, struct intel_encoder *encoder,
+					  const struct intel_crtc_state *crtc_state, int su_lines);
 void intel_vdsc_state_dump(struct drm_printer *p, int indent,
 			   const struct intel_crtc_state *crtc_state);
 int intel_vdsc_min_cdclk(const struct intel_crtc_state *crtc_state);