drm/amd/display: Deadlock/HPD Status/Crash Bug Fix

[why]
1. HPD callback function has deadlock problem
2. HPD status is not assigned
3. There is crash due to null pointer
4. link_enc is NULL in DPIA case

[How]
1. Fix deadlock problem by moving it out of the
   drm_modeset_lock
2. Assign HPD status from the notify of outbox
   from dmub FW
3. Fix the crash by checking if pin or enc exists
4. Use link_enc_cfg_get_link_enc_used_by_link to
   dynamically assign
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Jude Shih <shenshih@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -29,6 +29,7 @@
 #include "dm_services_types.h"
 #include "dc.h"
 #include "dc_link_dp.h"
+#include "link_enc_cfg.h"
 #include "dc/inc/core_types.h"
 #include "dal_asic_id.h"
 #include "dmub/dmub_srv.h"
@@ -648,6 +649,7 @@ void dmub_aux_setconfig_callback(struct amdgpu_device *adev, struct dmub_notific
 void dmub_hpd_callback(struct amdgpu_device *adev, struct dmub_notification *notify)
 {
 	struct amdgpu_dm_connector *aconnector;
+	struct amdgpu_dm_connector *hpd_aconnector = NULL;
 	struct drm_connector *connector;
 	struct drm_connector_list_iter iter;
 	struct dc_link *link;
@@ -678,13 +680,15 @@ void dmub_hpd_callback(struct amdgpu_device *adev, struct dmub_notification *not
 		aconnector = to_amdgpu_dm_connector(connector);
 		if (link && aconnector->dc_link == link) {
 			DRM_INFO("DMUB HPD callback: link_index=%u\n", link_index);
-			handle_hpd_irq_helper(aconnector);
+			hpd_aconnector = aconnector;
 			break;
 		}
 	}
 	drm_connector_list_iter_end(&iter);
 	drm_modeset_unlock(&dev->mode_config.connection_mutex);
 
+	if (hpd_aconnector)
+		handle_hpd_irq_helper(hpd_aconnector);
 }
 
 /**
@@ -747,8 +751,10 @@ static void dm_dmub_outbox1_low_irq(void *interrupt_params)
 	struct dmcub_trace_buf_entry entry = { 0 };
 	uint32_t count = 0;
 	struct dmub_hpd_work *dmub_hpd_wrk;
+	struct dc_link *plink = NULL;
 
-	if (dc_enable_dmub_notifications(adev->dm.dc)) {
+	if (dc_enable_dmub_notifications(adev->dm.dc) &&
+		irq_params->irq_src == DC_IRQ_SOURCE_DMCUB_OUTBOX) {
 		dmub_hpd_wrk = kzalloc(sizeof(*dmub_hpd_wrk), GFP_ATOMIC);
 		if (!dmub_hpd_wrk) {
 			DRM_ERROR("Failed to allocate dmub_hpd_wrk");
@@ -756,27 +762,28 @@ static void dm_dmub_outbox1_low_irq(void *interrupt_params)
 		}
 		INIT_WORK(&dmub_hpd_wrk->handle_hpd_work, dm_handle_hpd_work);
 
-		if (irq_params->irq_src == DC_IRQ_SOURCE_DMCUB_OUTBOX) {
-			do {
-				dc_stat_get_dmub_notification(adev->dm.dc, &notify);
-				if (notify.type > ARRAY_SIZE(dm->dmub_thread_offload)) {
-					DRM_ERROR("DM: notify type %d larger than the array size %zu!", notify.type,
-					ARRAY_SIZE(dm->dmub_thread_offload));
-					continue;
-				}
-				if (dm->dmub_thread_offload[notify.type] == true) {
-					dmub_hpd_wrk->dmub_notify = &notify;
-					dmub_hpd_wrk->adev = adev;
-					queue_work(adev->dm.delayed_hpd_wq, &dmub_hpd_wrk->handle_hpd_work);
-				} else {
-					dm->dmub_callback[notify.type](adev, &notify);
+		do {
+			dc_stat_get_dmub_notification(adev->dm.dc, &notify);
+			if (notify.type > ARRAY_SIZE(dm->dmub_thread_offload)) {
+				DRM_ERROR("DM: notify type %d invalid!", notify.type);
+				continue;
+			}
+			if (dm->dmub_thread_offload[notify.type] == true) {
+				dmub_hpd_wrk->dmub_notify = &notify;
+				dmub_hpd_wrk->adev = adev;
+				if (notify.type == DMUB_NOTIFICATION_HPD) {
+					plink = adev->dm.dc->links[notify.link_index];
+					if (plink) {
+						plink->hpd_status =
+							notify.hpd_status ==
+							DP_HPD_PLUG ? true : false;
+					}
 				}
-
-			} while (notify.pending_notification);
-
-		} else {
-			DRM_ERROR("DM: Failed to receive correct outbox IRQ !");
-		}
+				queue_work(adev->dm.delayed_hpd_wq, &dmub_hpd_wrk->handle_hpd_work);
+			} else {
+				dm->dmub_callback[notify.type](adev, &notify);
+			}
+		} while (notify.pending_notification);
 	}
 
 
@@ -794,7 +801,8 @@ static void dm_dmub_outbox1_low_irq(void *interrupt_params)
 
 	} while (count <= DMUB_TRACE_MAX_READ);
 
-	ASSERT(count <= DMUB_TRACE_MAX_READ);
+	if (count > DMUB_TRACE_MAX_READ)
+		DRM_DEBUG_DRIVER("Warning : count > DMUB_TRACE_MAX_READ");
 }
 #endif
 
@@ -2927,7 +2935,6 @@ static void handle_hpd_irq_helper(struct amdgpu_dm_connector *aconnector)
 	if (aconnector->base.force && new_connection_type == dc_connection_none) {
 		emulated_link_detect(aconnector->dc_link);
 
-
 		drm_modeset_lock_all(dev);
 		dm_restore_drm_connector_state(dev, connector);
 		drm_modeset_unlock_all(dev);
@@ -8113,7 +8120,17 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
 		break;
 	case DRM_MODE_CONNECTOR_DisplayPort:
 		aconnector->base.polled = DRM_CONNECTOR_POLL_HPD;
-		aconnector->base.ycbcr_420_allowed =
+		if (link->is_dig_mapping_flexible &&
+		    link->dc->res_pool->funcs->link_encs_assign) {
+			link->link_enc =
+				link_enc_cfg_get_link_enc_used_by_link(link->ctx->dc, link);
+			if (!link->link_enc)
+				link->link_enc =
+					link_enc_cfg_get_next_avail_link_enc(link->ctx->dc);
+		}
+
+		if (link->link_enc)
+			aconnector->base.ycbcr_420_allowed =
 			link->link_enc->features.dp_ycbcr420_supported ? true : false;
 		break;
 	case DRM_MODE_CONNECTOR_DVID:
@@ -8228,7 +8245,8 @@ create_i2c(struct ddc_service *ddc_service,
 	snprintf(i2c->base.name, sizeof(i2c->base.name), "AMDGPU DM i2c hw bus %d", link_index);
 	i2c_set_adapdata(&i2c->base, i2c);
 	i2c->ddc_service = ddc_service;
-	i2c->ddc_service->ddc_pin->hw_info.ddc_channel = link_index;
+	if (i2c->ddc_service->ddc_pin)
+		i2c->ddc_service->ddc_pin->hw_info.ddc_channel = link_index;
 
 	return i2c;
 }