drm/amd/display: Implement DCE analog link encoders (v2)

We support two kinds of analog connections:

1. DVI-I, which allows both digital and analog signals:
The DC code base only allows 1 encoder per connector, and the
preferred engine type is still going to be digital. So, for DVI-I
to work, we need to make sure the pre-existing link encoder can
also work with analog signals.

1. VGA, which only supports analog signals:
For VGA, we need to create a link encoder that only works with the
DAC without perturbing any digital transmitter functionality.
Since dce110_link_encoder already supports analog DVI-I,
just reuse that code for VGA as well.

v2:
Reduce code churn by reusing same link encoder for VGA and DVI-I.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_link_encoder.c

@@ -302,6 +302,10 @@ static void setup_panel_mode(
 	if (ctx->dc->caps.psp_setup_panel_mode)
 		return;
 
+	/* The code below is only applicable to encoders with a digital transmitter. */
+	if (enc110->base.transmitter == TRANSMITTER_UNKNOWN)
+		return;
+
 	ASSERT(REG(DP_DPHY_INTERNAL_CTRL));
 	value = REG_READ(DP_DPHY_INTERNAL_CTRL);
 
@@ -804,6 +808,33 @@ bool dce110_link_encoder_validate_dp_output(
 	return true;
 }
 
+static bool dce110_link_encoder_validate_rgb_output(
+	const struct dce110_link_encoder *enc110,
+	const struct dc_crtc_timing *crtc_timing)
+{
+	/* When the VBIOS doesn't specify any limits, use 400 MHz.
+	 * The value comes from amdgpu_atombios_get_clock_info.
+	 */
+	uint32_t max_pixel_clock_khz = 400000;
+
+	if (enc110->base.ctx->dc_bios->fw_info_valid &&
+	    enc110->base.ctx->dc_bios->fw_info.max_pixel_clock) {
+		max_pixel_clock_khz =
+			enc110->base.ctx->dc_bios->fw_info.max_pixel_clock;
+	}
+
+	if (crtc_timing->pix_clk_100hz > max_pixel_clock_khz * 10)
+		return false;
+
+	if (crtc_timing->display_color_depth != COLOR_DEPTH_888)
+		return false;
+
+	if (crtc_timing->pixel_encoding != PIXEL_ENCODING_RGB)
+		return false;
+
+	return true;
+}
+
 void dce110_link_encoder_construct(
 	struct dce110_link_encoder *enc110,
 	const struct encoder_init_data *init_data,
@@ -824,6 +855,7 @@ void dce110_link_encoder_construct(
 	enc110->base.connector = init_data->connector;
 
 	enc110->base.preferred_engine = ENGINE_ID_UNKNOWN;
+	enc110->base.analog_engine = init_data->analog_engine;
 
 	enc110->base.features = *enc_features;
 
@@ -847,6 +879,11 @@ void dce110_link_encoder_construct(
 		SIGNAL_TYPE_EDP |
 		SIGNAL_TYPE_HDMI_TYPE_A;
 
+	if ((enc110->base.connector.id == CONNECTOR_ID_DUAL_LINK_DVII ||
+	     enc110->base.connector.id == CONNECTOR_ID_SINGLE_LINK_DVII) &&
+		enc110->base.analog_engine != ENGINE_ID_UNKNOWN)
+		enc110->base.output_signals |= SIGNAL_TYPE_RGB;
+
 	/* For DCE 8.0 and 8.1, by design, UNIPHY is hardwired to DIG_BE.
 	 * SW always assign DIG_FE 1:1 mapped to DIG_FE for non-MST UNIPHY.
 	 * SW assign DIG_FE to non-MST UNIPHY first and MST last. So prefer
@@ -885,6 +922,13 @@ void dce110_link_encoder_construct(
 		enc110->base.preferred_engine = ENGINE_ID_DIGG;
 	break;
 	default:
+		if (init_data->analog_engine != ENGINE_ID_UNKNOWN) {
+			/* The connector is analog-only, ie. VGA */
+			enc110->base.preferred_engine = init_data->analog_engine;
+			enc110->base.output_signals = SIGNAL_TYPE_RGB;
+			enc110->base.transmitter = TRANSMITTER_UNKNOWN;
+			break;
+		}
 		ASSERT_CRITICAL(false);
 		enc110->base.preferred_engine = ENGINE_ID_UNKNOWN;
 	}
@@ -939,6 +983,10 @@ bool dce110_link_encoder_validate_output_with_stream(
 		is_valid = dce110_link_encoder_validate_dp_output(
 					enc110, &stream->timing);
 	break;
+	case SIGNAL_TYPE_RGB:
+		is_valid = dce110_link_encoder_validate_rgb_output(
+					enc110, &stream->timing);
+	break;
 	case SIGNAL_TYPE_EDP:
 	case SIGNAL_TYPE_LVDS:
 		is_valid = stream->timing.pixel_encoding == PIXEL_ENCODING_RGB;
@@ -969,6 +1017,10 @@ void dce110_link_encoder_hw_init(
 	cntl.coherent = false;
 	cntl.hpd_sel = enc110->base.hpd_source;
 
+	/* The code below is only applicable to encoders with a digital transmitter. */
+	if (enc110->base.transmitter == TRANSMITTER_UNKNOWN)
+		return;
+
 	if (enc110->base.connector.id == CONNECTOR_ID_EDP)
 		cntl.signal = SIGNAL_TYPE_EDP;
 
@@ -1034,6 +1086,8 @@ void dce110_link_encoder_setup(
 		/* DP MST */
 		REG_UPDATE(DIG_BE_CNTL, DIG_MODE, 5);
 		break;
+	case SIGNAL_TYPE_RGB:
+		break;
 	default:
 		ASSERT_CRITICAL(false);
 		/* invalid mode ! */
@@ -1282,6 +1336,24 @@ void dce110_link_encoder_disable_output(
 	struct bp_transmitter_control cntl = { 0 };
 	enum bp_result result;
 
+	switch (enc->analog_engine) {
+	case ENGINE_ID_DACA:
+		REG_UPDATE(DAC_ENABLE, DAC_ENABLE, 0);
+		break;
+	case ENGINE_ID_DACB:
+		/* DACB doesn't seem to be present on DCE6+,
+		 * although there are references to it in the register file.
+		 */
+		DC_LOG_ERROR("%s DACB is unsupported\n", __func__);
+		break;
+	default:
+		break;
+	}
+
+	/* The code below only applies to connectors that support digital signals. */
+	if (enc->transmitter == TRANSMITTER_UNKNOWN)
+		return;
+
 	if (!dce110_is_dig_enabled(enc)) {
 		/* OF_SKIP_POWER_DOWN_INACTIVE_ENCODER */
 		return;
@@ -1726,6 +1798,7 @@ void dce60_link_encoder_construct(
 	enc110->base.connector = init_data->connector;
 
 	enc110->base.preferred_engine = ENGINE_ID_UNKNOWN;
+	enc110->base.analog_engine = init_data->analog_engine;
 
 	enc110->base.features = *enc_features;
 
@@ -1749,6 +1822,11 @@ void dce60_link_encoder_construct(
 		SIGNAL_TYPE_EDP |
 		SIGNAL_TYPE_HDMI_TYPE_A;
 
+	if ((enc110->base.connector.id == CONNECTOR_ID_DUAL_LINK_DVII ||
+	     enc110->base.connector.id == CONNECTOR_ID_SINGLE_LINK_DVII) &&
+		enc110->base.analog_engine != ENGINE_ID_UNKNOWN)
+		enc110->base.output_signals |= SIGNAL_TYPE_RGB;
+
 	/* For DCE 8.0 and 8.1, by design, UNIPHY is hardwired to DIG_BE.
 	 * SW always assign DIG_FE 1:1 mapped to DIG_FE for non-MST UNIPHY.
 	 * SW assign DIG_FE to non-MST UNIPHY first and MST last. So prefer
@@ -1787,6 +1865,13 @@ void dce60_link_encoder_construct(
 		enc110->base.preferred_engine = ENGINE_ID_DIGG;
 	break;
 	default:
+		if (init_data->analog_engine != ENGINE_ID_UNKNOWN) {
+			/* The connector is analog-only, ie. VGA */
+			enc110->base.preferred_engine = init_data->analog_engine;
+			enc110->base.output_signals = SIGNAL_TYPE_RGB;
+			enc110->base.transmitter = TRANSMITTER_UNKNOWN;
+			break;
+		}
 		ASSERT_CRITICAL(false);
 		enc110->base.preferred_engine = ENGINE_ID_UNKNOWN;
 	}

drivers/gpu/drm/amd/display/dc/dce/dce_link_encoder.h

@@ -101,18 +101,21 @@
 	SRI(DP_SEC_CNTL, DP, id), \
 	SRI(DP_VID_STREAM_CNTL, DP, id), \
 	SRI(DP_DPHY_FAST_TRAINING, DP, id), \
-	SRI(DP_SEC_CNTL1, DP, id)
+	SRI(DP_SEC_CNTL1, DP, id), \
+	SR(DAC_ENABLE)
 #endif
 
 #define LE_DCE80_REG_LIST(id)\
 	SRI(DP_DPHY_INTERNAL_CTRL, DP, id), \
-	LE_COMMON_REG_LIST_BASE(id)
+	LE_COMMON_REG_LIST_BASE(id), \
+	SR(DAC_ENABLE)
 
 #define LE_DCE100_REG_LIST(id)\
 	LE_COMMON_REG_LIST_BASE(id), \
 	SRI(DP_DPHY_BS_SR_SWAP_CNTL, DP, id), \
 	SRI(DP_DPHY_INTERNAL_CTRL, DP, id), \
-	SR(DCI_MEM_PWR_STATUS)
+	SR(DCI_MEM_PWR_STATUS), \
+	SR(DAC_ENABLE)
 
 #define LE_DCE110_REG_LIST(id)\
 	LE_COMMON_REG_LIST_BASE(id), \
@@ -181,6 +184,9 @@ struct dce110_link_enc_registers {
 	uint32_t DP_DPHY_BS_SR_SWAP_CNTL;
 	uint32_t DP_DPHY_HBR2_PATTERN_CONTROL;
 	uint32_t DP_SEC_CNTL1;
+
+	/* DAC registers */
+	uint32_t DAC_ENABLE;
 };
 
 struct dce110_link_encoder {
@@ -215,10 +221,6 @@ bool dce110_link_encoder_validate_dvi_output(
 	enum signal_type signal,
 	const struct dc_crtc_timing *crtc_timing);
 
-bool dce110_link_encoder_validate_rgb_output(
-	const struct dce110_link_encoder *enc110,
-	const struct dc_crtc_timing *crtc_timing);
-
 bool dce110_link_encoder_validate_dp_output(
 	const struct dce110_link_encoder *enc110,
 	const struct dc_crtc_timing *crtc_timing);

drivers/gpu/drm/amd/display/dc/resource/dce100/dce100_resource.c

@@ -225,6 +225,7 @@ static const struct dce110_link_enc_registers link_enc_regs[] = {
 	link_regs(4),
 	link_regs(5),
 	link_regs(6),
+	{ .DAC_ENABLE = mmDAC_ENABLE },
 };
 
 #define stream_enc_regs(id)\
@@ -632,7 +633,20 @@ static struct link_encoder *dce100_link_encoder_create(
 		kzalloc(sizeof(struct dce110_link_encoder), GFP_KERNEL);
 	int link_regs_id;
 
-	if (!enc110 || enc_init_data->hpd_source >= ARRAY_SIZE(link_enc_hpd_regs))
+	if (!enc110)
+		return NULL;
+
+	if (enc_init_data->connector.id == CONNECTOR_ID_VGA) {
+		dce110_link_encoder_construct(enc110,
+			enc_init_data,
+			&link_enc_feature,
+			&link_enc_regs[ENGINE_ID_DACA],
+			NULL,
+			NULL);
+		return &enc110->base;
+	}
+
+	if (enc_init_data->hpd_source >= ARRAY_SIZE(link_enc_hpd_regs))
 		return NULL;
 
 	link_regs_id =

drivers/gpu/drm/amd/display/dc/resource/dce60/dce60_resource.c

@@ -240,7 +240,9 @@ static const struct dce110_link_enc_registers link_enc_regs[] = {
 	link_regs(2),
 	link_regs(3),
 	link_regs(4),
-	link_regs(5)
+	link_regs(5),
+	{0},
+	{ .DAC_ENABLE = mmDAC_ENABLE },
 };
 
 #define stream_enc_regs(id)\
@@ -726,7 +728,20 @@ static struct link_encoder *dce60_link_encoder_create(
 		kzalloc(sizeof(struct dce110_link_encoder), GFP_KERNEL);
 	int link_regs_id;
 
-	if (!enc110 || enc_init_data->hpd_source >= ARRAY_SIZE(link_enc_hpd_regs))
+	if (!enc110)
+		return NULL;
+
+	if (enc_init_data->connector.id == CONNECTOR_ID_VGA) {
+		dce110_link_encoder_construct(enc110,
+			enc_init_data,
+			&link_enc_feature,
+			&link_enc_regs[ENGINE_ID_DACA],
+			NULL,
+			NULL);
+		return &enc110->base;
+	}
+
+	if (enc_init_data->hpd_source >= ARRAY_SIZE(link_enc_hpd_regs))
 		return NULL;
 
 	link_regs_id =

drivers/gpu/drm/amd/display/dc/resource/dce80/dce80_resource.c

@@ -241,6 +241,7 @@ static const struct dce110_link_enc_registers link_enc_regs[] = {
 	link_regs(4),
 	link_regs(5),
 	link_regs(6),
+	{ .DAC_ENABLE = mmDAC_ENABLE },
 };
 
 #define stream_enc_regs(id)\
@@ -734,7 +735,20 @@ static struct link_encoder *dce80_link_encoder_create(
 		kzalloc(sizeof(struct dce110_link_encoder), GFP_KERNEL);
 	int link_regs_id;
 
-	if (!enc110 || enc_init_data->hpd_source >= ARRAY_SIZE(link_enc_hpd_regs))
+	if (!enc110)
+		return NULL;
+
+	if (enc_init_data->connector.id == CONNECTOR_ID_VGA) {
+		dce110_link_encoder_construct(enc110,
+			enc_init_data,
+			&link_enc_feature,
+			&link_enc_regs[ENGINE_ID_DACA],
+			NULL,
+			NULL);
+		return &enc110->base;
+	}
+
+	if (enc_init_data->hpd_source >= ARRAY_SIZE(link_enc_hpd_regs))
 		return NULL;
 
 	link_regs_id =