drm/amd/display: Query DMCUB for dp alt status

[Why]
To avoid hanging RDPCSPIPE when INTERCEPTB isn't set.

DMCUB owns control of that bit so DMCUB should manage returning the
information driver needs for link encoder control.

[How]
Add a new DMCUB command to return dp alt disable and dp4 information.
Reviewed-by: Hansen Dsouza <hansen.dsouza@amd.com>
Acked-by: Pavle Kotarac <Pavle.Kotarac@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn31/dcn31_dio_link_encoder.c

@@ -67,6 +67,39 @@
 #define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
 #endif
 
+static uint8_t phy_id_from_transmitter(enum transmitter t)
+{
+	uint8_t phy_id;
+
+	switch (t) {
+	case TRANSMITTER_UNIPHY_A:
+		phy_id = 0;
+		break;
+	case TRANSMITTER_UNIPHY_B:
+		phy_id = 1;
+		break;
+	case TRANSMITTER_UNIPHY_C:
+		phy_id = 2;
+		break;
+	case TRANSMITTER_UNIPHY_D:
+		phy_id = 3;
+		break;
+	case TRANSMITTER_UNIPHY_E:
+		phy_id = 4;
+		break;
+	case TRANSMITTER_UNIPHY_F:
+		phy_id = 5;
+		break;
+	case TRANSMITTER_UNIPHY_G:
+		phy_id = 6;
+		break;
+	default:
+		phy_id = 0;
+		break;
+	}
+	return phy_id;
+}
+
 void dcn31_link_encoder_set_dio_phy_mux(
 	struct link_encoder *enc,
 	enum encoder_type_select sel,
@@ -536,57 +569,45 @@ void dcn31_link_encoder_disable_output(
 bool dcn31_link_encoder_is_in_alt_mode(struct link_encoder *enc)
 {
 	struct dcn10_link_encoder *enc10 = TO_DCN10_LINK_ENC(enc);
-	uint32_t dp_alt_mode_disable;
+	struct dc_dmub_srv *dc_dmub_srv = enc->ctx->dmub_srv;
+	union dmub_rb_cmd cmd;
 	bool is_usb_c_alt_mode = false;
 
-	if (enc->features.flags.bits.DP_IS_USB_C) {
-		if (enc->ctx->asic_id.hw_internal_rev != YELLOW_CARP_B0) {
-			// [Note] no need to check hw_internal_rev once phy mux selection is ready
-			REG_GET(RDPCSTX_PHY_CNTL6, RDPCS_PHY_DPALT_DISABLE, &dp_alt_mode_disable);
-		} else {
-		/*
-		 * B0 phys use a new set of registers to check whether alt mode is disabled.
-		 * if value == 1 alt mode is disabled, otherwise it is enabled.
-		 */
-			if ((enc10->base.transmitter == TRANSMITTER_UNIPHY_A)
-					|| (enc10->base.transmitter == TRANSMITTER_UNIPHY_B)
-					|| (enc10->base.transmitter == TRANSMITTER_UNIPHY_E)) {
-				REG_GET(RDPCSTX_PHY_CNTL6, RDPCS_PHY_DPALT_DISABLE, &dp_alt_mode_disable);
-			} else {
-			// [Note] need to change TRANSMITTER_UNIPHY_C/D to F/G once phy mux selection is ready
-				REG_GET(RDPCSPIPE_PHY_CNTL6, RDPCS_PHY_DPALT_DISABLE, &dp_alt_mode_disable);
-			}
-		}
+	if (enc->features.flags.bits.DP_IS_USB_C && dc_dmub_srv) {
+		memset(&cmd, 0, sizeof(cmd));
+		cmd.query_dp_alt.header.type = DMUB_CMD__VBIOS;
+		cmd.query_dp_alt.header.sub_type = DMUB_CMD__VBIOS_TRANSMITTER_QUERY_DP_ALT;
+		cmd.query_dp_alt.header.payload_bytes = sizeof(cmd.panel_cntl.data);
+		cmd.query_dp_alt.data.phy_id = phy_id_from_transmitter(enc10->base.transmitter);
+
+		if (!dc_dmub_srv_cmd_with_reply_data(dc_dmub_srv, &cmd))
+			return false;
 
-		is_usb_c_alt_mode = (dp_alt_mode_disable == 0);
+		is_usb_c_alt_mode = (cmd.query_dp_alt.data.is_dp_alt_disable == 0);
 	}
 
 	return is_usb_c_alt_mode;
 }
 
-void dcn31_link_encoder_get_max_link_cap(struct link_encoder *enc,
-										 struct dc_link_settings *link_settings)
+void dcn31_link_encoder_get_max_link_cap(struct link_encoder *enc, struct dc_link_settings *link_settings)
 {
 	struct dcn10_link_encoder *enc10 = TO_DCN10_LINK_ENC(enc);
-	uint32_t is_in_usb_c_dp4_mode = 0;
+	struct dc_dmub_srv *dc_dmub_srv = enc->ctx->dmub_srv;
+	union dmub_rb_cmd cmd;
 
 	dcn10_link_encoder_get_max_link_cap(enc, link_settings);
 
-	/* in usb c dp2 mode, max lane count is 2 */
-	if (enc->funcs->is_in_alt_mode && enc->funcs->is_in_alt_mode(enc)) {
-		if (enc->ctx->asic_id.hw_internal_rev != YELLOW_CARP_B0) {
-			// [Note] no need to check hw_internal_rev once phy mux selection is ready
-			REG_GET(RDPCSTX_PHY_CNTL6, RDPCS_PHY_DPALT_DP4, &is_in_usb_c_dp4_mode);
-		} else {
-			if ((enc10->base.transmitter == TRANSMITTER_UNIPHY_A)
-					|| (enc10->base.transmitter == TRANSMITTER_UNIPHY_B)
-					|| (enc10->base.transmitter == TRANSMITTER_UNIPHY_E)) {
-				REG_GET(RDPCSTX_PHY_CNTL6, RDPCS_PHY_DPALT_DP4, &is_in_usb_c_dp4_mode);
-			} else {
-				REG_GET(RDPCSPIPE_PHY_CNTL6, RDPCS_PHY_DPALT_DP4, &is_in_usb_c_dp4_mode);
-			}
-		}
-		if (!is_in_usb_c_dp4_mode)
+	if (enc->features.flags.bits.DP_IS_USB_C && dc_dmub_srv) {
+		memset(&cmd, 0, sizeof(cmd));
+		cmd.query_dp_alt.header.type = DMUB_CMD__VBIOS;
+		cmd.query_dp_alt.header.sub_type = DMUB_CMD__VBIOS_TRANSMITTER_QUERY_DP_ALT;
+		cmd.query_dp_alt.header.payload_bytes = sizeof(cmd.panel_cntl.data);
+		cmd.query_dp_alt.data.phy_id = phy_id_from_transmitter(enc10->base.transmitter);
+
+		if (!dc_dmub_srv_cmd_with_reply_data(dc_dmub_srv, &cmd))
+			return;
+
+		if (cmd.query_dp_alt.data.is_usb && cmd.query_dp_alt.data.is_dp4 == 0)
 			link_settings->lane_count = MIN(LANE_COUNT_TWO, link_settings->lane_count);
 	}
 }

drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h

@@ -408,7 +408,14 @@ enum dmub_cmd_vbios_type {
 	 * Enables or disables power gating.
 	 */
 	DMUB_CMD__VBIOS_ENABLE_DISP_POWER_GATING = 3,
+	/**
+	 * Controls embedded panels.
+	 */
 	DMUB_CMD__VBIOS_LVTMA_CONTROL = 15,
+	/**
+	 * Query DP alt status on a transmitter.
+	 */
+	DMUB_CMD__VBIOS_TRANSMITTER_QUERY_DP_ALT  = 26,
 };
 
 //==============================================================================
@@ -2393,6 +2400,24 @@ struct dmub_rb_cmd_lvtma_control {
 	struct dmub_cmd_lvtma_control_data data;
 };
 
+/**
+ * Data passed in/out in a DMUB_CMD__VBIOS_TRANSMITTER_QUERY_DP_ALT command.
+ */
+struct dmub_rb_cmd_transmitter_query_dp_alt_data {
+	uint8_t phy_id; /**< 0=UNIPHYA, 1=UNIPHYB, 2=UNIPHYC, 3=UNIPHYD, 4=UNIPHYE, 5=UNIPHYF */
+	uint8_t is_usb; /**< is phy is usb */
+	uint8_t is_dp_alt_disable; /**< is dp alt disable */
+	uint8_t is_dp4; /**< is dp in 4 lane */
+};
+
+/**
+ * Definition of a DMUB_CMD__VBIOS_TRANSMITTER_QUERY_DP_ALT command.
+ */
+struct dmub_rb_cmd_transmitter_query_dp_alt {
+	struct dmub_cmd_header header; /**< header */
+	struct dmub_rb_cmd_transmitter_query_dp_alt_data data; /**< payload */
+};
+
 /**
  * Maximum number of bytes a chunk sent to DMUB for parsing
  */
@@ -2600,6 +2625,10 @@ union dmub_rb_cmd {
 	 * Definition of a DMUB_CMD__VBIOS_LVTMA_CONTROL command.
 	 */
 	struct dmub_rb_cmd_lvtma_control lvtma_control;
+	/**
+	 * Definition of a DMUB_CMD__VBIOS_TRANSMITTER_QUERY_DP_ALT command.
+	 */
+	struct dmub_rb_cmd_transmitter_query_dp_alt query_dp_alt;
 	/**
 	 * Definition of a DMUB_CMD__DPIA_DIG1_CONTROL command.
 	 */