drm/amd/display: Add reinstate dram in the FPO logic

In order to handle FPO correctly, we need to reinstate the dram values.
This function adds the required code to handle the vblank stretch and
the dram calculation.
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.h

@@ -99,6 +99,9 @@ enum dc_status dcn30_add_stream_to_ctx(
 
 void dcn30_update_bw_bounding_box(struct dc *dc, struct clk_bw_params *bw_params);
 
+bool dcn30_can_support_mclk_switch_using_fw_based_vblank_stretch(struct dc *dc, struct dc_state *context);
 void dcn30_setup_mclk_switch_using_fw_based_vblank_stretch(struct dc *dc, struct dc_state *context);
+int dcn30_find_dummy_latency_index_for_fw_based_mclk_switch(struct dc *dc, struct dc_state *context,
+		display_e2e_pipe_params_st *pipes, int pipe_cnt, int vlevel);
 
 #endif /* _DCN30_RESOURCE_H_ */

drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c

@@ -30,6 +30,7 @@
 #include "display_mode_vba_util_32.h"
 // We need this includes for WATERMARKS_* defines
 #include "clk_mgr/dcn32/dcn32_smu13_driver_if.h"
+#include "dcn30/dcn30_resource.h"
 
 #define DC_LOGGER_INIT(logger)
 
@@ -1597,6 +1598,10 @@ void dcn32_calculate_wm_and_dlg_fpu(struct dc *dc, struct dc_state *context,
 	double dcfclk_from_validation = context->bw_ctx.dml.vba.DCFCLKState[vlevel][context->bw_ctx.dml.vba.maxMpcComb];
 	bool pstate_en = context->bw_ctx.dml.vba.DRAMClockChangeSupport[vlevel][context->bw_ctx.dml.vba.maxMpcComb] !=
 			dm_dram_clock_change_unsupported;
+	unsigned int dummy_latency_index = 0;
+	int maxMpcComb = context->bw_ctx.dml.vba.maxMpcComb;
+	unsigned int min_dram_speed_mts = context->bw_ctx.dml.vba.DRAMSpeed;
+	unsigned int min_dram_speed_mts_margin;
 
 	dc_assert_fp_enabled();
 
@@ -1606,6 +1611,32 @@ void dcn32_calculate_wm_and_dlg_fpu(struct dc *dc, struct dc_state *context,
 		pstate_en = true;
 	}
 
+	context->bw_ctx.bw.dcn.clk.fw_based_mclk_switching = false;
+
+	if (!pstate_en) {
+		/* only when the mclk switch can not be natural, is the fw based vblank stretch attempted */
+		context->bw_ctx.bw.dcn.clk.fw_based_mclk_switching =
+			dcn30_can_support_mclk_switch_using_fw_based_vblank_stretch(dc, context);
+
+		if (context->bw_ctx.bw.dcn.clk.fw_based_mclk_switching) {
+			dummy_latency_index = dcn30_find_dummy_latency_index_for_fw_based_mclk_switch(dc,
+				context, pipes, pipe_cnt, vlevel);
+
+			/* After calling dcn30_find_dummy_latency_index_for_fw_based_mclk_switch
+			 * we reinstate the original dram_clock_change_latency_us on the context
+			 * and all variables that may have changed up to this point, except the
+			 * newly found dummy_latency_index
+			 */
+			context->bw_ctx.dml.soc.dram_clock_change_latency_us =
+					dc->clk_mgr->bw_params->wm_table.nv_entries[WM_A].dml_input.pstate_latency_us;
+			dcn32_internal_validate_bw(dc, context, pipes, &pipe_cnt, &vlevel, false);
+			maxMpcComb = context->bw_ctx.dml.vba.maxMpcComb;
+			dcfclk = context->bw_ctx.dml.vba.DCFCLKState[vlevel][context->bw_ctx.dml.vba.maxMpcComb];
+			pstate_en = context->bw_ctx.dml.vba.DRAMClockChangeSupport[vlevel][maxMpcComb] !=
+					dm_dram_clock_change_unsupported;
+		}
+	}
+
 	/* Set B:
 	 * For Set B calculations use clocks from clock_limits[2] when available i.e. when SMU is present,
 	 * otherwise use arbitrary low value from spreadsheet for DCFCLK as lower is safer for watermark
@@ -1687,19 +1718,33 @@ void dcn32_calculate_wm_and_dlg_fpu(struct dc *dc, struct dc_state *context,
 	pipes[0].clks_cfg.socclk_mhz = context->bw_ctx.dml.soc.clock_limits[vlevel].socclk_mhz;
 
 	if (dc->clk_mgr->bw_params->wm_table.nv_entries[WM_C].valid) {
-		unsigned int min_dram_speed_mts = context->bw_ctx.dml.vba.DRAMSpeed;
-		unsigned int min_dram_speed_mts_margin = 160;
+		min_dram_speed_mts = context->bw_ctx.dml.vba.DRAMSpeed;
+		min_dram_speed_mts_margin = 160;
+
+		context->bw_ctx.dml.soc.dram_clock_change_latency_us =
+			dc->clk_mgr->bw_params->dummy_pstate_table[0].dummy_pstate_latency_us;
+
+		if (context->bw_ctx.dml.vba.DRAMClockChangeSupport[vlevel][maxMpcComb] ==
+			dm_dram_clock_change_unsupported) {
+			int min_dram_speed_mts_offset = dc->clk_mgr->bw_params->clk_table.num_entries - 1;
 
-		if (context->bw_ctx.dml.vba.DRAMClockChangeSupport[vlevel][context->bw_ctx.dml.vba.maxMpcComb] ==
-				dm_dram_clock_change_unsupported)
-			min_dram_speed_mts = dc->clk_mgr->bw_params->clk_table.entries[dc->clk_mgr->bw_params->clk_table.num_entries - 1].memclk_mhz * 16;
+			min_dram_speed_mts =
+				dc->clk_mgr->bw_params->clk_table.entries[min_dram_speed_mts_offset].memclk_mhz * 16;
+		}
 
-		/* find largest table entry that is lower than dram speed, but lower than DPM0 still uses DPM0 */
-		for (i = 3; i > 0; i--)
-			if (min_dram_speed_mts + min_dram_speed_mts_margin > dc->clk_mgr->bw_params->dummy_pstate_table[i].dram_speed_mts)
+		if (!context->bw_ctx.bw.dcn.clk.fw_based_mclk_switching) {
+			/* find largest table entry that is lower than dram speed,
+			 * but lower than DPM0 still uses DPM0
+			 */
+			for (dummy_latency_index = 3; dummy_latency_index > 0; dummy_latency_index--)
+				if (min_dram_speed_mts + min_dram_speed_mts_margin >
+					dc->clk_mgr->bw_params->dummy_pstate_table[dummy_latency_index].dram_speed_mts)
 					break;
+		}
+
+		context->bw_ctx.dml.soc.dram_clock_change_latency_us =
+			dc->clk_mgr->bw_params->dummy_pstate_table[dummy_latency_index].dummy_pstate_latency_us;
 
-		context->bw_ctx.dml.soc.dram_clock_change_latency_us = dc->clk_mgr->bw_params->dummy_pstate_table[i].dummy_pstate_latency_us;
 		context->bw_ctx.dml.soc.fclk_change_latency_us = dc->clk_mgr->bw_params->wm_table.nv_entries[WM_C].dml_input.fclk_change_latency_us;
 		context->bw_ctx.dml.soc.sr_enter_plus_exit_time_us = dc->clk_mgr->bw_params->wm_table.nv_entries[WM_C].dml_input.sr_enter_plus_exit_time_us;
 		context->bw_ctx.dml.soc.sr_exit_time_us = dc->clk_mgr->bw_params->wm_table.nv_entries[WM_C].dml_input.sr_exit_time_us;
@@ -1770,6 +1815,8 @@ void dcn32_calculate_wm_and_dlg_fpu(struct dc *dc, struct dc_state *context,
 		context->bw_ctx.dml.soc.dram_clock_change_latency_us =
 				dc->clk_mgr->bw_params->wm_table.nv_entries[WM_A].dml_input.pstate_latency_us;
 
+	if (context->bw_ctx.bw.dcn.clk.fw_based_mclk_switching)
+		dcn30_setup_mclk_switch_using_fw_based_vblank_stretch(dc, context);
 }
 
 static void dcn32_get_optimal_dcfclk_fclk_for_uclk(unsigned int uclk_mts,