drm/amd/display: Wait for hubp read line for Pollock

[Why]
Underflow occurred while hubp ret pipe read is idle and the
second pipe is powered up and added. Flickering and underflow
are only observed on Pollock.

[How]
Check the hubp ret pipe read prior to unlock pipes.
Reviewed-by: Hersen Wu <hersenxs.wu@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Agustin Gutierrez <agustin.gutierrez@amd.com>
Signed-off-by: Becle Lee <becle.lee@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/dcn10/dcn10_hubp.c

@@ -1311,6 +1311,20 @@ void hubp1_set_flip_int(struct hubp *hubp)
 	return;
 }
 
+/**
+ * hubp1_wait_pipe_read_start - wait for hubp ret path starting read.
+ *
+ * @hubp: hubp struct reference.
+ */
+void hubp1_wait_pipe_read_start(struct hubp *hubp)
+{
+	struct dcn10_hubp *hubp1 = TO_DCN10_HUBP(hubp);
+
+	REG_WAIT(HUBPRET_READ_LINE_STATUS,
+		PIPE_READ_VBLANK, 0,
+		 1, 1000);
+}
+
 void hubp1_init(struct hubp *hubp)
 {
 	//do nothing
@@ -1345,6 +1359,7 @@ static const struct hubp_funcs dcn10_hubp_funcs = {
 	.hubp_soft_reset = hubp1_soft_reset,
 	.hubp_in_blank = hubp1_in_blank,
 	.hubp_set_flip_int = hubp1_set_flip_int,
+	.hubp_wait_pipe_read_start = hubp1_wait_pipe_read_start,
 };
 
 /*****************************************/

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hubp.h

@@ -76,6 +76,7 @@
 	SRI(DCSURF_SURFACE_CONTROL, HUBPREQ, id),\
 	SRI(DCSURF_SURFACE_FLIP_INTERRUPT, HUBPREQ, id),\
 	SRI(HUBPRET_CONTROL, HUBPRET, id),\
+	SRI(HUBPRET_READ_LINE_STATUS, HUBPRET, id),\
 	SRI(DCN_EXPANSION_MODE, HUBPREQ, id),\
 	SRI(DCHUBP_REQ_SIZE_CONFIG, HUBP, id),\
 	SRI(DCHUBP_REQ_SIZE_CONFIG_C, HUBP, id),\
@@ -186,6 +187,7 @@
 	uint32_t DCSURF_SURFACE_CONTROL; \
 	uint32_t DCSURF_SURFACE_FLIP_INTERRUPT; \
 	uint32_t HUBPRET_CONTROL; \
+	uint32_t HUBPRET_READ_LINE_STATUS; \
 	uint32_t DCN_EXPANSION_MODE; \
 	uint32_t DCHUBP_REQ_SIZE_CONFIG; \
 	uint32_t DCHUBP_REQ_SIZE_CONFIG_C; \
@@ -338,6 +340,7 @@
 	HUBP_SF(HUBPRET0_HUBPRET_CONTROL, DET_BUF_PLANE1_BASE_ADDRESS, mask_sh),\
 	HUBP_SF(HUBPRET0_HUBPRET_CONTROL, CROSSBAR_SRC_CB_B, mask_sh),\
 	HUBP_SF(HUBPRET0_HUBPRET_CONTROL, CROSSBAR_SRC_CR_R, mask_sh),\
+	HUBP_SF(HUBPRET0_HUBPRET_READ_LINE_STATUS, PIPE_READ_VBLANK, mask_sh),\
 	HUBP_SF(HUBPREQ0_DCN_EXPANSION_MODE, DRQ_EXPANSION_MODE, mask_sh),\
 	HUBP_SF(HUBPREQ0_DCN_EXPANSION_MODE, PRQ_EXPANSION_MODE, mask_sh),\
 	HUBP_SF(HUBPREQ0_DCN_EXPANSION_MODE, MRQ_EXPANSION_MODE, mask_sh),\
@@ -538,6 +541,7 @@
 	type DET_BUF_PLANE1_BASE_ADDRESS;\
 	type CROSSBAR_SRC_CB_B;\
 	type CROSSBAR_SRC_CR_R;\
+	type PIPE_READ_VBLANK;\
 	type DRQ_EXPANSION_MODE;\
 	type PRQ_EXPANSION_MODE;\
 	type MRQ_EXPANSION_MODE;\

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_resource.c

@@ -863,6 +863,21 @@ static struct dce_hwseq *dcn10_hwseq_create(
 		hws->wa.DEGVIDCN10_253 = true;
 		hws->wa.false_optc_underflow = true;
 		hws->wa.DEGVIDCN10_254 = true;
+
+		if ((ctx->asic_id.chip_family == FAMILY_RV) &&
+			ASICREV_IS_RAVEN2(ctx->asic_id.hw_internal_rev))
+			switch (ctx->asic_id.pci_revision_id) {
+			case PRID_POLLOCK_94:
+			case PRID_POLLOCK_95:
+			case PRID_POLLOCK_E9:
+			case PRID_POLLOCK_EA:
+			case PRID_POLLOCK_EB:
+				hws->wa.wait_hubpret_read_start_during_mpo_transition = true;
+				break;
+			default:
+				hws->wa.wait_hubpret_read_start_during_mpo_transition = false;
+				break;
+			}
 	}
 	return hws;
 }

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c

@@ -1739,6 +1739,16 @@ void dcn20_program_front_end_for_ctx(
 					|| pipe->stream->update_flags.raw)
 				&& hws->funcs.program_all_writeback_pipes_in_tree)
 			hws->funcs.program_all_writeback_pipes_in_tree(dc, pipe->stream, context);
+
+		/* Avoid underflow by check of pipe line read when adding 2nd plane. */
+		if (hws->wa.wait_hubpret_read_start_during_mpo_transition &&
+			!pipe->top_pipe &&
+			pipe->stream &&
+			pipe->plane_res.hubp->funcs->hubp_wait_pipe_read_start &&
+			dc->current_state->stream_status[0].plane_count == 1 &&
+			context->stream_status[0].plane_count > 1) {
+			pipe->plane_res.hubp->funcs->hubp_wait_pipe_read_start(pipe->plane_res.hubp);
+		}
 	}
 }
 

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

@@ -195,6 +195,7 @@ struct hubp_funcs {
 
 	void (*hubp_set_flip_int)(struct hubp *hubp);
 
+	void (*hubp_wait_pipe_read_start)(struct hubp *hubp);
 };
 
 #endif

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

@@ -42,6 +42,7 @@ struct dce_hwseq_wa {
 	bool DEGVIDCN21;
 	bool disallow_self_refresh_during_multi_plane_transition;
 	bool dp_hpo_and_otg_sequence;
+	bool wait_hubpret_read_start_during_mpo_transition;
 };
 
 struct hwseq_wa_state {