drm/amd/display: Add z-state support policy for dcn35

[Why]
DML2 means that the dcn3x policy for calculating z-state support
no longer runs from validate_bandwidth.

This means we are unconditionally allowing Z8, the hardware default.

[How]
Port the policy over to DCN35, but with a few modifications:
- Don't use min_dst_y_next_start as a check for Z8/Z10 allow
- Add support for overriding the Z10 stutter period per ASIC
- Cleanup the code to make the policy assignment more clear
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dc.h

@@ -874,6 +874,7 @@ struct dc_debug_options {
 	unsigned int seamless_boot_odm_combine;
 	unsigned int force_odm_combine_4to1; //bit vector based on otg inst
 	int minimum_z8_residency_time;
+	int minimum_z10_residency_time;
 	bool disable_z9_mpc;
 	unsigned int force_fclk_khz;
 	bool enable_tri_buf;

drivers/gpu/drm/amd/display/dc/dcn35/dcn35_resource.c

@@ -1712,6 +1712,13 @@ static bool dcn35_validate_bandwidth(struct dc *dc,
 
 	out = dml2_validate(dc, context, fast_validate);
 
+	if (fast_validate)
+		return out;
+
+	DC_FP_START();
+	dcn35_decide_zstate_support(dc, context);
+	DC_FP_END();
+
 	return out;
 }
 

drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c

@@ -507,3 +507,37 @@ int dcn35_populate_dml_pipes_from_context_fpu(struct dc *dc,
 
 	return pipe_cnt;
 }
+
+void dcn35_decide_zstate_support(struct dc *dc, struct dc_state *context)
+{
+	enum dcn_zstate_support_state support = DCN_ZSTATE_SUPPORT_DISALLOW;
+	unsigned int i, plane_count = 0;
+
+	for (i = 0; i < dc->res_pool->pipe_count; i++) {
+		if (context->res_ctx.pipe_ctx[i].plane_state)
+			plane_count++;
+	}
+
+	if (plane_count == 0) {
+		support = DCN_ZSTATE_SUPPORT_ALLOW;
+	} else if (plane_count == 1 && context->stream_count == 1 && context->streams[0]->signal == SIGNAL_TYPE_EDP) {
+		struct dc_link *link = context->streams[0]->sink->link;
+		bool is_pwrseq0 = link && link->link_index == 0;
+		bool is_psr1 = link && link->psr_settings.psr_version == DC_PSR_VERSION_1 && !link->panel_config.psr.disable_psr;
+		int minmum_z8_residency =
+			dc->debug.minimum_z8_residency_time > 0 ? dc->debug.minimum_z8_residency_time : 1000;
+		bool allow_z8 = context->bw_ctx.dml.vba.StutterPeriod > (double)minmum_z8_residency;
+		int minmum_z10_residency =
+			dc->debug.minimum_z10_residency_time > 0 ? dc->debug.minimum_z10_residency_time : 5000;
+		bool allow_z10 = context->bw_ctx.dml.vba.StutterPeriod > (double)minmum_z10_residency;
+
+		if (is_pwrseq0 && allow_z10)
+			support = DCN_ZSTATE_SUPPORT_ALLOW;
+		else if (is_pwrseq0 && is_psr1)
+			support = allow_z8 ? DCN_ZSTATE_SUPPORT_ALLOW_Z8_Z10_ONLY : DCN_ZSTATE_SUPPORT_ALLOW_Z10_ONLY;
+		else if (allow_z8)
+			support = DCN_ZSTATE_SUPPORT_ALLOW_Z8_ONLY;
+	}
+
+	context->bw_ctx.bw.dcn.clk.zstate_support = support;
+}

drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.h

@@ -39,4 +39,6 @@ int dcn35_populate_dml_pipes_from_context_fpu(struct dc *dc,
 					      display_e2e_pipe_params_st *pipes,
 					      bool fast_validate);
 
+void dcn35_decide_zstate_support(struct dc *dc, struct dc_state *context);
+
 #endif