drm/amd/display: Add periodic detection for IPS

[Why]
HPD interrupt cannot be handled in IPS2 state.
So if there's a display topology change while system in IPS2
it can be missed.

[How]
Implement worker to check each 5 sec in IPS for HPD.

Reviewed-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1838,6 +1838,9 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 			DRM_ERROR("amdgpu: failed to initialize vblank_workqueue.\n");
 	}
 
+	if (adev->dm.dc->caps.ips_support && adev->dm.dc->config.disable_ips == DMUB_IPS_ENABLE)
+		adev->dm.idle_workqueue = idle_create_workqueue(adev);
+
 	if (adev->dm.dc->caps.max_links > 0 && adev->family >= AMDGPU_FAMILY_RV) {
 		adev->dm.hdcp_workqueue = hdcp_create_workqueue(adev, &init_params.cp_psp, adev->dm.dc);
 
@@ -1935,6 +1938,16 @@ static void amdgpu_dm_fini(struct amdgpu_device *adev)
 		adev->dm.vblank_control_workqueue = NULL;
 	}
 
+	if (adev->dm.idle_workqueue) {
+		if (adev->dm.idle_workqueue->running) {
+			adev->dm.idle_workqueue->enable = false;
+			flush_work(&adev->dm.idle_workqueue->work);
+		}
+
+		kfree(adev->dm.idle_workqueue);
+		adev->dm.idle_workqueue = NULL;
+	}
+
 	amdgpu_dm_destroy_drm_device(&adev->dm);
 
 #if defined(CONFIG_DRM_AMD_SECURE_DISPLAY)

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

@@ -137,6 +137,13 @@ struct vblank_control_work {
 	bool enable;
 };
 
+struct idle_workqueue {
+	struct work_struct work;
+	struct amdgpu_display_manager *dm;
+	bool enable;
+	bool running;
+};
+
 /**
  * struct amdgpu_dm_backlight_caps - Information about backlight
  *
@@ -487,6 +494,7 @@ struct amdgpu_display_manager {
 	 * Deferred work for vblank control events.
 	 */
 	struct workqueue_struct *vblank_control_workqueue;
+	struct idle_workqueue *idle_workqueue;
 
 	struct drm_atomic_state *cached_state;
 	struct dc_state *cached_dc_state;
@@ -956,4 +964,5 @@ amdgpu_dm_find_first_crtc_matching_connector(struct drm_atomic_state *state,
 					     struct drm_crtc *crtc);
 
 int convert_dc_color_depth_into_bpc(enum dc_color_depth display_color_depth);
+struct idle_workqueue *idle_create_workqueue(struct amdgpu_device *adev);
 #endif /* __AMDGPU_DM_H__ */

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

@@ -35,6 +35,9 @@
 #include "amdgpu_dm_trace.h"
 #include "amdgpu_dm_debugfs.h"
 
+#define HPD_DETECTION_PERIOD_uS 5000000
+#define HPD_DETECTION_TIME_uS 1000
+
 void amdgpu_dm_crtc_handle_vblank(struct amdgpu_crtc *acrtc)
 {
 	struct drm_crtc *crtc = &acrtc->base;
@@ -146,9 +149,63 @@ static void amdgpu_dm_crtc_set_panel_sr_feature(
 		struct amdgpu_dm_connector *aconn =
 			(struct amdgpu_dm_connector *) vblank_work->stream->dm_stream_context;
 
-		if (!aconn->disallow_edp_enter_psr)
+		if (!aconn->disallow_edp_enter_psr) {
+			struct amdgpu_display_manager *dm = vblank_work->dm;
+
 			amdgpu_dm_psr_enable(vblank_work->stream);
+			if (dm->idle_workqueue &&
+			    dm->dc->idle_optimizations_allowed &&
+			    dm->idle_workqueue->enable &&
+			    !dm->idle_workqueue->running)
+				schedule_work(&dm->idle_workqueue->work);
 		}
+	}
+}
+
+static void amdgpu_dm_idle_worker(struct work_struct *work)
+{
+	struct idle_workqueue *idle_work;
+
+	idle_work = container_of(work, struct idle_workqueue, work);
+	idle_work->dm->idle_workqueue->running = true;
+	fsleep(HPD_DETECTION_PERIOD_uS);
+	mutex_lock(&idle_work->dm->dc_lock);
+	while (idle_work->enable) {
+		if (!idle_work->dm->dc->idle_optimizations_allowed)
+			break;
+
+		dc_allow_idle_optimizations(idle_work->dm->dc, false);
+
+		mutex_unlock(&idle_work->dm->dc_lock);
+		fsleep(HPD_DETECTION_TIME_uS);
+		mutex_lock(&idle_work->dm->dc_lock);
+
+		if (!amdgpu_dm_psr_is_active_allowed(idle_work->dm))
+			break;
+
+		dc_allow_idle_optimizations(idle_work->dm->dc, true);
+		mutex_unlock(&idle_work->dm->dc_lock);
+		fsleep(HPD_DETECTION_PERIOD_uS);
+		mutex_lock(&idle_work->dm->dc_lock);
+	}
+	mutex_unlock(&idle_work->dm->dc_lock);
+	idle_work->dm->idle_workqueue->running = false;
+}
+
+struct idle_workqueue *idle_create_workqueue(struct amdgpu_device *adev)
+{
+	struct idle_workqueue *idle_work;
+
+	idle_work = kzalloc(sizeof(*idle_work), GFP_KERNEL);
+	if (ZERO_OR_NULL_PTR(idle_work))
+		return NULL;
+
+	idle_work->dm = &adev->dm;
+	idle_work->enable = false;
+	idle_work->running = false;
+	INIT_WORK(&idle_work->work, amdgpu_dm_idle_worker);
+
+	return idle_work;
 }
 
 static void amdgpu_dm_crtc_vblank_control_worker(struct work_struct *work)

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

@@ -1261,7 +1261,10 @@ void dm_set_phyd32clk(struct dc_context *ctx, int freq_khz)
 
 void dm_helpers_enable_periodic_detection(struct dc_context *ctx, bool enable)
 {
-	/* TODO: add periodic detection implementation */
+	struct amdgpu_device *adev = ctx->driver_context;
+
+	if (adev->dm.idle_workqueue)
+		adev->dm.idle_workqueue->enable = enable;
 }
 
 void dm_helpers_dp_mst_update_branch_bandwidth(

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

@@ -223,3 +223,31 @@ bool amdgpu_dm_psr_disable_all(struct amdgpu_display_manager *dm)
 	return dc_set_psr_allow_active(dm->dc, false);
 }
 
+/*
+ * amdgpu_dm_psr_is_active_allowed() - check if psr is allowed on any stream
+ * @dm:  pointer to amdgpu_display_manager
+ *
+ * Return: true if allowed
+ */
+
+bool amdgpu_dm_psr_is_active_allowed(struct amdgpu_display_manager *dm)
+{
+	unsigned int i;
+	bool allow_active = false;
+
+	for (i = 0; i < dm->dc->current_state->stream_count ; i++) {
+		struct dc_link *link;
+		struct dc_stream_state *stream = dm->dc->current_state->streams[i];
+
+		link = stream->link;
+		if (!link)
+			continue;
+		if (link->psr_settings.psr_feature_enabled &&
+		    link->psr_settings.psr_allow_active) {
+			allow_active = true;
+			break;
+		}
+	}
+
+	return allow_active;
+}

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.h

@@ -36,5 +36,6 @@ void amdgpu_dm_psr_enable(struct dc_stream_state *stream);
 bool amdgpu_dm_link_setup_psr(struct dc_stream_state *stream);
 bool amdgpu_dm_psr_disable(struct dc_stream_state *stream);
 bool amdgpu_dm_psr_disable_all(struct amdgpu_display_manager *dm);
+bool amdgpu_dm_psr_is_active_allowed(struct amdgpu_display_manager *dm);
 
 #endif /* AMDGPU_DM_AMDGPU_DM_PSR_H_ */