drm/i915: Extract intel_dbuf_mdclk_min_tracker_update()

Extract the stuff that writes the dbuf/mbus ratio stuff
into its own function. Will help with correctly sequencing
the operations done during mbus programming.
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240402155016.13733-9-ville.syrjala@linux.intel.com

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

@@ -3653,6 +3653,30 @@ void intel_dbuf_mdclk_cdclk_ratio_update(struct drm_i915_private *i915, u8 ratio
 			     DBUF_MIN_TRACKER_STATE_SERVICE(ratio - 1));
 }
 
+static void intel_dbuf_mdclk_min_tracker_update(struct intel_atomic_state *state)
+{
+	struct drm_i915_private *i915 = to_i915(state->base.dev);
+	const struct intel_dbuf_state *old_dbuf_state =
+		intel_atomic_get_old_dbuf_state(state);
+	const struct intel_dbuf_state *new_dbuf_state =
+		intel_atomic_get_new_dbuf_state(state);
+
+	if (DISPLAY_VER(i915) >= 20 &&
+	    old_dbuf_state->mdclk_cdclk_ratio != new_dbuf_state->mdclk_cdclk_ratio) {
+		/*
+		 * For Xe2LPD and beyond, when there is a change in the ratio
+		 * between MDCLK and CDCLK, updates to related registers need to
+		 * happen at a specific point in the CDCLK change sequence. In
+		 * that case, we defer to the call to
+		 * intel_dbuf_mdclk_cdclk_ratio_update() to the CDCLK logic.
+		 */
+		return;
+	}
+
+	intel_dbuf_mdclk_cdclk_ratio_update(i915, new_dbuf_state->mdclk_cdclk_ratio,
+					    new_dbuf_state->joined_mbus);
+}
+
 static void intel_dbuf_mbus_join_update(struct intel_atomic_state *state)
 {
 	struct drm_i915_private *i915 = to_i915(state->base.dev);
@@ -3683,10 +3707,6 @@ static void intel_dbuf_mbus_join_update(struct intel_atomic_state *state)
 static void update_mbus_pre_enable(struct intel_atomic_state *state)
 {
 	struct drm_i915_private *i915 = to_i915(state->base.dev);
-	const struct intel_dbuf_state *old_dbuf_state =
-		intel_atomic_get_old_dbuf_state(state);
-	const struct intel_dbuf_state *new_dbuf_state =
-		intel_atomic_get_new_dbuf_state(state);
 
 	if (!HAS_MBUS_JOINING(i915))
 		return;
@@ -3697,20 +3717,7 @@ static void update_mbus_pre_enable(struct intel_atomic_state *state)
 	 */
 	intel_dbuf_mbus_join_update(state);
 
-	if (DISPLAY_VER(i915) >= 20 &&
-	    old_dbuf_state->mdclk_cdclk_ratio != new_dbuf_state->mdclk_cdclk_ratio) {
-		/*
-		 * For Xe2LPD and beyond, when there is a change in the ratio
-		 * between MDCLK and CDCLK, updates to related registers need to
-		 * happen at a specific point in the CDCLK change sequence. In
-		 * that case, we defer to the call to
-		 * intel_dbuf_mdclk_cdclk_ratio_update() to the CDCLK logic.
-		 */
-		return;
-	}
-
-	intel_dbuf_mdclk_cdclk_ratio_update(i915, new_dbuf_state->mdclk_cdclk_ratio,
-					    new_dbuf_state->joined_mbus);
+	intel_dbuf_mdclk_min_tracker_update(state);
 }
 
 void intel_dbuf_pre_plane_update(struct intel_atomic_state *state)