drm/amd/display: Implement FIFO enable sequence on DCN32

[WHY?]
FIFO enable sequence is incomplete as it is currently implemented in FW,
and requires reset to prevent the FIFO to be enabled in an invalid
state. This cannot be done until DIG FE is connected to the BE.

[HOW?]
Add FIFO enable sequence in driver for dcn32 with reset after DIG FE is
connected to BE.
Tested-by: NDaniel Wheeler <Daniel.Wheeler@amd.com>
Reviewed-by: NAlvin Lee <Alvin.Lee2@amd.com>
Acked-by: NRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: NDillon Varone <Dillon.Varone@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_dio_stream_encoder.c

@@ -421,6 +421,33 @@ static void enc32_set_dig_input_mode(struct stream_encoder *enc, unsigned int pi
 	REG_UPDATE(DIG_FIFO_CTRL0, DIG_FIFO_OUTPUT_PIXEL_MODE, pix_per_container == 2 ? 0x1 : 0x0);
 }
 
+static void enc32_reset_fifo(struct stream_encoder *enc, bool reset)
+{
+	struct dcn10_stream_encoder *enc1 = DCN10STRENC_FROM_STRENC(enc);
+	uint32_t reset_val = reset ? 1 : 0;
+	uint32_t is_symclk_on;
+
+	REG_UPDATE(DIG_FIFO_CTRL0, DIG_FIFO_RESET, reset_val);
+	REG_GET(DIG_FE_CNTL, DIG_SYMCLK_FE_ON, &is_symclk_on);
+
+	if (is_symclk_on)
+		REG_WAIT(DIG_FIFO_CTRL0, DIG_FIFO_RESET_DONE, reset_val, 10, 5000);
+	else
+		udelay(10);
+}
+
+static void enc32_enable_fifo(struct stream_encoder *enc)
+{
+	struct dcn10_stream_encoder *enc1 = DCN10STRENC_FROM_STRENC(enc);
+
+	REG_UPDATE(DIG_FIFO_CTRL0, DIG_FIFO_READ_START_LEVEL, 0x7);
+
+	enc32_reset_fifo(enc, true);
+	enc32_reset_fifo(enc, false);
+
+	REG_UPDATE(DIG_FIFO_CTRL0, DIG_FIFO_ENABLE, 1);
+}
+
 static const struct stream_encoder_funcs dcn32_str_enc_funcs = {
 	.dp_set_odm_combine =
 		enc32_dp_set_odm_combine,
@@ -466,6 +493,7 @@ static const struct stream_encoder_funcs dcn32_str_enc_funcs = {
 	.hdmi_reset_stream_attribute = enc1_reset_hdmi_stream_attribute,
 
 	.set_input_mode = enc32_set_dig_input_mode,
+	.enable_fifo = enc32_enable_fifo,
 };
 
 void dcn32_dio_stream_encoder_construct(