drm/i915/display/icl: Save Master transcoder in slave's crtc_state for Transcoder Port Sync

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 transcoder in all the slave
CRTC states. This is needed to select the master CRTC/transcoder
while configuring transcoder port sync for the corresponding slaves.

v6:
Rebase (manasi)
v5:
* Address Ville's comments
* Just pass crtc_state, no need to check GEN (Ville)
v4:
* Rebase
v3:
* Use master_tramscoder instead of master_crtc for valid
HW state readouts (Ville)
v2:
* Move this to intel_mode_set_pipe_config(Jani N, Ville)
* Use slave_bitmask to save associated slaves in master crtc state (Ville)

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191018172725.1338-1-manasi.d.navare@intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -519,6 +519,20 @@ needs_modeset(const struct intel_crtc_state *state)
 	return drm_atomic_crtc_needs_modeset(&state->base);
 }
 
+bool
+is_trans_port_sync_mode(const struct intel_crtc_state *crtc_state)
+{
+	return (crtc_state->master_transcoder != INVALID_TRANSCODER ||
+		crtc_state->sync_mode_slaves_mask);
+}
+
+static bool
+is_trans_port_sync_master(const struct intel_crtc_state *crtc_state)
+{
+	return (crtc_state->master_transcoder == INVALID_TRANSCODER &&
+		crtc_state->sync_mode_slaves_mask);
+}
+
 /*
  * Platform specific helpers to calculate the port PLL loopback- (clock.m),
  * and post-divider (clock.p) values, pre- (clock.vco) and post-divided fast
@@ -11794,6 +11808,91 @@ static bool c8_planes_changed(const struct intel_crtc_state *new_crtc_state)
 	return !old_crtc_state->c8_planes != !new_crtc_state->c8_planes;
 }
 
+static int icl_add_sync_mode_crtcs(struct intel_crtc_state *crtc_state)
+{
+	struct drm_crtc *crtc = crtc_state->base.crtc;
+	struct intel_atomic_state *state = to_intel_atomic_state(crtc_state->base.state);
+	struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
+	struct drm_connector *master_connector, *connector;
+	struct drm_connector_state *connector_state;
+	struct drm_connector_list_iter conn_iter;
+	struct drm_crtc *master_crtc = NULL;
+	struct drm_crtc_state *master_crtc_state;
+	struct intel_crtc_state *master_pipe_config;
+	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->base, connector, connector_state, i) {
+		if (connector_state->crtc != crtc)
+			continue;
+		if (!connector->has_tile)
+			continue;
+		if (crtc_state->base.mode.hdisplay != connector->tile_h_size ||
+		    crtc_state->base.mode.vdisplay != connector->tile_v_size)
+			return 0;
+		if (connector->tile_h_loc == connector->num_h_tile - 1 &&
+		    connector->tile_v_loc == connector->num_v_tile - 1)
+			continue;
+		crtc_state->sync_mode_slaves_mask = 0;
+		tile_group_id = connector->tile_group->id;
+		drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
+		drm_for_each_connector_iter(master_connector, &conn_iter) {
+			struct drm_connector_state *master_conn_state = NULL;
+
+			if (!master_connector->has_tile)
+				continue;
+			if (master_connector->tile_h_loc != master_connector->num_h_tile - 1 ||
+			    master_connector->tile_v_loc != master_connector->num_v_tile - 1)
+				continue;
+			if (master_connector->tile_group->id != tile_group_id)
+				continue;
+
+			master_conn_state = drm_atomic_get_connector_state(&state->base,
+									   master_connector);
+			if (IS_ERR(master_conn_state)) {
+				drm_connector_list_iter_end(&conn_iter);
+				return PTR_ERR(master_conn_state);
+			}
+			if (master_conn_state->crtc) {
+				master_crtc = master_conn_state->crtc;
+				break;
+			}
+		}
+		drm_connector_list_iter_end(&conn_iter);
+
+		if (!master_crtc) {
+			DRM_DEBUG_KMS("Could not find Master CRTC for Slave CRTC %d\n",
+				      connector_state->crtc->base.id);
+			return -EINVAL;
+		}
+
+		master_crtc_state = drm_atomic_get_crtc_state(&state->base,
+							      master_crtc);
+		if (IS_ERR(master_crtc_state))
+			return PTR_ERR(master_crtc_state);
+
+		master_pipe_config = to_intel_crtc_state(master_crtc_state);
+		crtc_state->master_transcoder = master_pipe_config->cpu_transcoder;
+		master_pipe_config->sync_mode_slaves_mask |=
+			BIT(crtc_state->cpu_transcoder);
+		DRM_DEBUG_KMS("Master Transcoder = %s added for Slave CRTC = %d, slave transcoder bitmask = %d\n",
+			      transcoder_name(crtc_state->master_transcoder),
+			      crtc_state->base.crtc->base.id,
+			      master_pipe_config->sync_mode_slaves_mask);
+	}
+
+	return 0;
+}
+
 static int intel_crtc_atomic_check(struct intel_atomic_state *state,
 				   struct intel_crtc *crtc)
 {
@@ -12292,6 +12391,13 @@ clear_intel_crtc_state(struct intel_crtc_state *crtc_state)
 	if (IS_G4X(dev_priv) ||
 	    IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
 		saved_state->wm = crtc_state->wm;
+	/*
+	 * Save the slave bitmask which gets filled for master crtc state during
+	 * slave atomic check call.
+	 */
+	if (is_trans_port_sync_master(crtc_state))
+		saved_state->sync_mode_slaves_mask =
+			crtc_state->sync_mode_slaves_mask;
 
 	/* Keep base drm_crtc_state intact, only clear our extended struct */
 	BUILD_BUG_ON(offsetof(struct intel_crtc_state, base));
@@ -12385,6 +12491,15 @@ encoder_retry:
 	drm_mode_set_crtcinfo(&pipe_config->base.adjusted_mode,
 			      CRTC_STEREO_DOUBLE);
 
+	/* Set the crtc_state defaults for trans_port_sync */
+	pipe_config->master_transcoder = INVALID_TRANSCODER;
+	ret = icl_add_sync_mode_crtcs(pipe_config);
+	if (ret) {
+		DRM_DEBUG_KMS("Cannot assign Sync Mode CRTCs: %d\n",
+			      ret);
+		return ret;
+	}
+
 	/* Pass our mode to the connectors and the CRTC to give them a chance to
 	 * adjust it according to limitations or connector properties, and also
 	 * a chance to reject the mode entirely.
@@ -12900,6 +13015,9 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
 	PIPE_CONF_CHECK_INFOFRAME(hdmi);
 	PIPE_CONF_CHECK_INFOFRAME(drm);
 
+	PIPE_CONF_CHECK_I(sync_mode_slaves_mask);
+	PIPE_CONF_CHECK_I(master_transcoder);
+
 #undef PIPE_CONF_CHECK_X
 #undef PIPE_CONF_CHECK_I
 #undef PIPE_CONF_CHECK_BOOL

drivers/gpu/drm/i915/display/intel_display.h

@@ -93,6 +93,7 @@ enum pipe {
 #define pipe_name(p) ((p) + 'A')
 
 enum transcoder {
+	INVALID_TRANSCODER = -1,
 	/*
 	 * The following transcoders have a 1:1 transcoder -> pipe mapping,
 	 * keep their values fixed: the code assumes that TRANSCODER_A=0, the
@@ -462,6 +463,7 @@ enum drm_mode_status
 intel_mode_valid_max_plane_size(struct drm_i915_private *dev_priv,
 				const struct drm_display_mode *mode);
 enum phy intel_port_to_phy(struct drm_i915_private *i915, enum port port);
+bool is_trans_port_sync_mode(const struct intel_crtc_state *state);
 
 void intel_plane_destroy(struct drm_plane *plane);
 void i830_enable_pipe(struct drm_i915_private *dev_priv, enum pipe pipe);

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -991,6 +991,12 @@ struct intel_crtc_state {
 
 	/* Forward Error correction State */
 	bool fec_enable;
+
+	/* Pointer to master transcoder in case of tiled displays */
+	enum transcoder master_transcoder;
+
+	/* Bitmask to indicate slaves attached */
+	u8 sync_mode_slaves_mask;
 };
 
 struct intel_crtc {