drm/amd/display: fix dccg root clock optimization related hang

[Why]
enable dpp rcg before we disable dppclk in hw_init cause system
hang/reboot

[How]
we remove dccg rcg related code from init into a separate function and
call it after we init pipe

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Qili Lu <qili.lu@amd.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Qili Lu

drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c

@@ -1748,10 +1748,6 @@ void dccg35_init(struct dccg *dccg)
 			dccg35_set_dpstreamclk_root_clock_gating(dccg, otg_inst, false);
 		}
 
-	if (dccg->ctx->dc->debug.root_clock_optimization.bits.dpp)
-		for (otg_inst = 0; otg_inst < 4; otg_inst++)
-			dccg35_set_dppclk_root_clock_gating(dccg, otg_inst, 0);
-
 /*
 	dccg35_enable_global_fgcg_rep(
 		dccg, dccg->ctx->dc->debug.enable_fine_grain_clock_gating.bits
@@ -2336,6 +2332,14 @@ static void dccg35_disable_symclk_se_cb(
 	/* DMU PHY sequence switches SYMCLK_BE (link_enc_inst) to ref clock once PHY is turned off */
 }
 
+void dccg35_root_gate_disable_control(struct dccg *dccg, uint32_t pipe_idx, uint32_t disable_clock_gating)
+{
+
+	if (dccg->ctx->dc->debug.root_clock_optimization.bits.dpp) {
+		dccg35_set_dppclk_root_clock_gating(dccg, pipe_idx, disable_clock_gating);
+	}
+}
+
 static const struct dccg_funcs dccg35_funcs_new = {
 	.update_dpp_dto = dccg35_update_dpp_dto_cb,
 	.dpp_root_clock_control = dccg35_dpp_root_clock_control_cb,
@@ -2396,7 +2400,7 @@ static const struct dccg_funcs dccg35_funcs = {
 	.enable_symclk_se = dccg35_enable_symclk_se,
 	.disable_symclk_se = dccg35_disable_symclk_se,
 	.set_dtbclk_p_src = dccg35_set_dtbclk_p_src,
-
+	.dccg_root_gate_disable_control = dccg35_root_gate_disable_control,
 };
 
 struct dccg *dccg35_create(

drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.h

@@ -241,6 +241,7 @@ struct dccg *dccg35_create(
 void dccg35_init(struct dccg *dccg);
 
 void dccg35_enable_global_fgcg_rep(struct dccg *dccg, bool value);
+void dccg35_root_gate_disable_control(struct dccg *dccg, uint32_t pipe_idx, uint32_t disable_clock_gating);
 
 
 #endif //__DCN35_DCCG_H__

drivers/gpu/drm/amd/display/dc/hwss/dcn35/dcn35_hwseq.c

@@ -240,6 +240,10 @@ void dcn35_init_hw(struct dc *dc)
 			dc->res_pool->hubbub->funcs->allow_self_refresh_control(dc->res_pool->hubbub,
 					!dc->res_pool->hubbub->ctx->dc->debug.disable_stutter);
 	}
+	if (res_pool->dccg->funcs->dccg_root_gate_disable_control) {
+		for (i = 0; i < res_pool->pipe_count; i++)
+			res_pool->dccg->funcs->dccg_root_gate_disable_control(res_pool->dccg, i, 0);
+	}
 
 	for (i = 0; i < res_pool->audio_count; i++) {
 		struct audio *audio = res_pool->audios[i];

drivers/gpu/drm/amd/display/dc/inc/hw/dccg.h

@@ -213,6 +213,7 @@ struct dccg_funcs {
 			uint32_t otg_inst);
 	void (*set_dto_dscclk)(struct dccg *dccg, uint32_t dsc_inst);
 	void (*set_ref_dscclk)(struct dccg *dccg, uint32_t dsc_inst);
+	void (*dccg_root_gate_disable_control)(struct dccg *dccg, uint32_t pipe_idx, uint32_t disable_clock_gating);
 };
 
 #endif //__DAL_DCCG_H__