drm/amd/display: Add outbox notification support for HPD redetect

[Why]
HPD sense changes can occur during low power states and need to be
notified from firmware to driver. Upon notification the hotplug
redetection routines should execute.

[How]
Add Support in DMUB srv and DMUB srv stat for receiving these
notifications. DM can hook them up and process the HPD redetection
once received.
Reviewed-by: Duncan Ma <duncan.ma@amd.com>
Acked-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dmub/dmub_srv.h

@@ -137,6 +137,7 @@ enum dmub_notification_type {
 	DMUB_NOTIFICATION_HPD_IRQ,
 	DMUB_NOTIFICATION_SET_CONFIG_REPLY,
 	DMUB_NOTIFICATION_DPIA_NOTIFICATION,
+	DMUB_NOTIFICATION_HPD_SENSE_NOTIFY,
 	DMUB_NOTIFICATION_MAX
 };
 
@@ -560,6 +561,7 @@ struct dmub_notification {
 		 * DPIA notification command.
 		 */
 		struct dmub_rb_cmd_dpia_notification dpia_notification;
+		struct dmub_rb_cmd_hpd_sense_notify_data hpd_sense_notify;
 	};
 };
 

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

@@ -1285,6 +1285,10 @@ enum dmub_out_cmd_type {
 	 * Command type used for USB4 DPIA notification
 	 */
 	DMUB_OUT_CMD__DPIA_NOTIFICATION = 5,
+	/**
+	 * Command type used for HPD redetect notification
+	 */
+	DMUB_OUT_CMD__HPD_SENSE_NOTIFY = 6,
 };
 
 /* DMUB_CMD__DPIA command sub-types. */
@@ -2468,6 +2472,22 @@ struct dmub_rb_cmd_query_hpd_state {
 	struct dmub_cmd_hpd_state_query_data data;
 };
 
+/**
+ * struct dmub_rb_cmd_hpd_sense_notify - HPD sense notification data.
+ */
+struct dmub_rb_cmd_hpd_sense_notify_data {
+	uint32_t old_hpd_sense_mask; /**< Old HPD sense mask */
+	uint32_t new_hpd_sense_mask; /**< New HPD sense mask */
+};
+
+/**
+ * struct dmub_rb_cmd_hpd_sense_notify - DMUB_OUT_CMD__HPD_SENSE_NOTIFY command.
+ */
+struct dmub_rb_cmd_hpd_sense_notify {
+	struct dmub_cmd_header header; /**< header */
+	struct dmub_rb_cmd_hpd_sense_notify_data data; /**< payload */
+};
+
 /*
  * Command IDs should be treated as stable ABI.
  * Do not reuse or modify IDs.
@@ -5204,6 +5224,10 @@ union dmub_rb_out_cmd {
 	 * DPIA notification command.
 	 */
 	struct dmub_rb_cmd_dpia_notification dpia_notification;
+	/**
+	 * HPD sense notification command.
+	 */
+	struct dmub_rb_cmd_hpd_sense_notify hpd_sense_notify;
 };
 #pragma pack(pop)
 

drivers/gpu/drm/amd/display/dmub/src/dmub_srv_stat.c

@@ -113,6 +113,12 @@ enum dmub_status dmub_srv_stat_get_notification(struct dmub_srv *dmub,
 				notify->result = DPIA_BW_ALLOC_CAPS_CHANGED;
 		}
 		break;
+	case DMUB_OUT_CMD__HPD_SENSE_NOTIFY:
+		notify->type = DMUB_NOTIFICATION_HPD_SENSE_NOTIFY;
+		dmub_memcpy(&notify->hpd_sense_notify,
+			    &cmd.hpd_sense_notify.data,
+			    sizeof(cmd.hpd_sense_notify.data));
+		break;
 	default:
 		notify->type = DMUB_NOTIFICATION_NO_DATA;
 		break;