[Intel-gfx] [PATCH 1/2] drm/i915/icl: Assign genlock CRTC pointer in all slave CRTC states for tiled displays

[Manasi Navare]

In case of tiled displays when the two tiles are sent across two CRTCs
over two separate DP SST connectors, we need a mechanism to synchronize
the two CRTCs and their corresponding transcoders.
So use the master-slave mode where there is one master corresponding
to last horizontal and vertical tile that needs to be genlocked with
all other slave tiles.
This patch identifies saves the master CRTC pointer in all the slave
CRTC states. This pointer is needed to select the master CRTC/transcoder
while configuring transcoder port sync for the corresponding slaves.

Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Matt Roper <matthew.d.roper at intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 84 ++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h     |  3 +
 2 files changed, 87 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 8ff7aa8cb3cf..9980a4ed8c9c 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -11281,6 +11281,86 @@ static int icl_check_nv12_planes(struct intel_crtc_state *crtc_state)
 	return 0;
 }
 
+static int icl_add_genlock_crtcs(struct drm_device *dev,
+				 struct drm_atomic_state *state)
+{
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	struct drm_connector *genlock_connector, *connector;
+	struct drm_connector_state *connector_state;
+	struct drm_connector_list_iter conn_iter;
+	struct drm_crtc *genlock_crtc = NULL;
+	struct drm_crtc_state *genlock_crtc_state;
+	struct intel_crtc_state *slave_crtc_state;
+	int i, tile_group_id;
+
+	if (INTEL_GEN(dev_priv) < 11)
+		return 0;
+
+	/*
+	 * In case of tiled displays there could be one or more slaves but there is
+	 * only one master. Lets make the CRTC used by the connector corresponding
+	 * to the last horizonal and last vertical tile a master/genlock CRTC.
+	 * All the other CRTCs corresponding to other tiles of the same Tile group
+	 * are the slave CRTCs and hold a pointer to their genlock CRTC.
+	 */
+	for_each_new_connector_in_state(state, connector, connector_state, i) {
+		if (!connector_state->crtc)
+			continue;
+		if (!connector->has_tile)
+			continue;
+		if (connector->tile_h_loc == connector->num_h_tile - 1 &&
+		    connector->tile_v_loc == connector->num_v_tile - 1)
+			continue;
+		slave_crtc_state = to_intel_crtc_state(
+			drm_atomic_get_new_crtc_state(state,
+						      connector_state->crtc));
+		slave_crtc_state->genlock_crtc = NULL;
+		tile_group_id = connector->tile_group->id;
+		drm_connector_list_iter_begin(dev, &conn_iter);
+		drm_for_each_connector_iter(genlock_connector, &conn_iter) {
+			struct drm_connector_state *genlock_conn_state = NULL;
+
+			if (!genlock_connector->has_tile)
+				continue;
+			if (genlock_connector->tile_h_loc != genlock_connector->num_h_tile - 1 ||
+			    genlock_connector->tile_v_loc != genlock_connector->num_v_tile - 1)
+				continue;
+			if (genlock_connector->tile_group->id != tile_group_id)
+				continue;
+
+			genlock_conn_state = drm_atomic_get_connector_state(state,
+									    genlock_connector);
+			if (IS_ERR(genlock_conn_state)) {
+				drm_connector_list_iter_end(&conn_iter);
+				return PTR_ERR(genlock_conn_state);
+			}
+			if (genlock_conn_state->crtc) {
+				genlock_crtc = genlock_conn_state->crtc;
+				break;
+			}
+		}
+		drm_connector_list_iter_end(&conn_iter);
+
+		if (!genlock_crtc) {
+			DRM_DEBUG_KMS("Could not add Genlock CRTC for Slave CRTC %d\n",
+				      connector_state->crtc->base.id);
+			return -EINVAL;
+		}
+
+		genlock_crtc_state = drm_atomic_get_crtc_state(state,
+							       genlock_crtc);
+		if (IS_ERR(genlock_crtc_state))
+			return PTR_ERR(genlock_crtc_state);
+
+		slave_crtc_state->genlock_crtc = to_intel_crtc(genlock_crtc);
+		DRM_DEBUG_KMS("Genlock CRTC = %d added for Slave CRTC = %d\n",
+			      genlock_crtc->base.id,
+			      slave_crtc_state->base.crtc->base.id);
+	}
+
+	return 0;
+}
+
 static int intel_crtc_atomic_check(struct drm_crtc *crtc,
 				   struct drm_crtc_state *crtc_state)
 {
@@ -13098,6 +13178,10 @@ static int intel_atomic_check(struct drm_device *dev,
 	if (ret)
 		return ret;
 
+	ret = icl_add_genlock_crtcs(dev, state);
+	if (ret)
+		return ret;
+
 	for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, crtc_state, i) {
 		struct intel_crtc_state *pipe_config =
 			to_intel_crtc_state(crtc_state);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 4d7ae579fc92..b41728946b73 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1074,6 +1074,9 @@ struct intel_crtc_state {
 
 	/* Forward Error correction State */
 	bool fec_enable;
+
+	/* Pointer to master/genlock crtc in case of tiled displays */
+	struct intel_crtc *genlock_crtc;
 };
 
 struct intel_crtc {
-- 
2.19.1