drm/amd/display: Reset fifo after enable otg

[Why]
In fast boot sequence, when change dispclk, otg is disabled but digfe
is enabled. This may cause dig fifo error.

[How]
Reset dig fifo after enable otg.
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: JinZe.Xu <JinZe.Xu@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/dce110/dce110_hw_sequencer.c

@@ -1602,6 +1602,11 @@ static enum dc_status apply_single_controller_ctx_to_hw(
 			pipe_ctx->stream_res.stream_enc,
 			pipe_ctx->stream_res.tg->inst);
 
+	if (dc_is_dp_signal(pipe_ctx->stream->signal) &&
+		pipe_ctx->stream_res.stream_enc->funcs->reset_fifo)
+		pipe_ctx->stream_res.stream_enc->funcs->reset_fifo(
+			pipe_ctx->stream_res.stream_enc);
+
 	if (dc_is_dp_signal(pipe_ctx->stream->signal))
 		dp_source_sequence_trace(link, DPCD_SOURCE_SEQ_AFTER_CONNECT_DIG_FE_OTG);
 

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c

@@ -902,6 +902,19 @@ void enc1_stream_encoder_stop_dp_info_packets(
 
 }
 
+void enc1_stream_encoder_reset_fifo(
+	struct stream_encoder *enc)
+{
+	struct dcn10_stream_encoder *enc1 = DCN10STRENC_FROM_STRENC(enc);
+
+	/* set DIG_START to 0x1 to reset FIFO */
+	REG_UPDATE(DIG_FE_CNTL, DIG_START, 1);
+	udelay(100);
+
+	/* write 0 to take the FIFO out of reset */
+	REG_UPDATE(DIG_FE_CNTL, DIG_START, 0);
+}
+
 void enc1_stream_encoder_dp_blank(
 	struct dc_link *link,
 	struct stream_encoder *enc)
@@ -1587,6 +1600,8 @@ static const struct stream_encoder_funcs dcn10_str_enc_funcs = {
 		enc1_stream_encoder_send_immediate_sdp_message,
 	.stop_dp_info_packets =
 		enc1_stream_encoder_stop_dp_info_packets,
+	.reset_fifo =
+		enc1_stream_encoder_reset_fifo,
 	.dp_blank =
 		enc1_stream_encoder_dp_blank,
 	.dp_unblank =

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.h

@@ -626,6 +626,9 @@ void enc1_stream_encoder_send_immediate_sdp_message(
 void enc1_stream_encoder_stop_dp_info_packets(
 	struct stream_encoder *enc);
 
+void enc1_stream_encoder_reset_fifo(
+	struct stream_encoder *enc);
+
 void enc1_stream_encoder_dp_blank(
 	struct dc_link *link,
 	struct stream_encoder *enc);

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_stream_encoder.c

@@ -593,6 +593,8 @@ static const struct stream_encoder_funcs dcn20_str_enc_funcs = {
 		enc1_stream_encoder_send_immediate_sdp_message,
 	.stop_dp_info_packets =
 		enc1_stream_encoder_stop_dp_info_packets,
+	.reset_fifo =
+		enc1_stream_encoder_reset_fifo,
 	.dp_blank =
 		enc1_stream_encoder_dp_blank,
 	.dp_unblank =

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_dio_stream_encoder.c

@@ -805,6 +805,8 @@ static const struct stream_encoder_funcs dcn30_str_enc_funcs = {
 		enc3_stream_encoder_update_dp_info_packets,
 	.stop_dp_info_packets =
 		enc1_stream_encoder_stop_dp_info_packets,
+	.reset_fifo =
+		enc1_stream_encoder_reset_fifo,
 	.dp_blank =
 		enc1_stream_encoder_dp_blank,
 	.dp_unblank =

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

@@ -164,6 +164,10 @@ struct stream_encoder_funcs {
 	void (*stop_dp_info_packets)(
 		struct stream_encoder *enc);
 
+	void (*reset_fifo)(
+		struct stream_encoder *enc
+	);
+
 	void (*dp_blank)(
 		struct dc_link *link,
 		struct stream_encoder *enc);