drm/i915: Split vlv_compute_pipe_wm() into two

Split vlv_compute_pipe_wm() into two halves. The first half computes
the new raw watermarks, and the second half munges those up into real
watermarks for the particular pipe.

We can reuse the second half for watermark sanitation as well.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220622155452.32587-3-ville.syrjala@linux.intel.com
Reviewed-by: Stanislav Lisovskiy <stanslav.lisovskiy@intel.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -1865,64 +1865,17 @@ static bool vlv_raw_crtc_wm_is_valid(const struct intel_crtc_state *crtc_state,
 		vlv_raw_plane_wm_is_valid(crtc_state, PLANE_CURSOR, level);
 }
 
-static int vlv_compute_pipe_wm(struct intel_atomic_state *state,
-			       struct intel_crtc *crtc)
+static int _vlv_compute_pipe_wm(struct intel_crtc_state *crtc_state)
 {
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	struct intel_crtc_state *crtc_state =
-		intel_atomic_get_new_crtc_state(state, crtc);
 	struct vlv_wm_state *wm_state = &crtc_state->wm.vlv.optimal;
 	const struct vlv_fifo_state *fifo_state =
 		&crtc_state->wm.vlv.fifo_state;
 	u8 active_planes = crtc_state->active_planes & ~BIT(PLANE_CURSOR);
 	int num_active_planes = hweight8(active_planes);
-	bool needs_modeset = drm_atomic_crtc_needs_modeset(&crtc_state->uapi);
-	const struct intel_plane_state *old_plane_state;
-	const struct intel_plane_state *new_plane_state;
-	struct intel_plane *plane;
 	enum plane_id plane_id;
-	int level, ret, i;
-	unsigned int dirty = 0;
-
-	for_each_oldnew_intel_plane_in_state(state, plane,
-					     old_plane_state,
-					     new_plane_state, i) {
-		if (new_plane_state->hw.crtc != &crtc->base &&
-		    old_plane_state->hw.crtc != &crtc->base)
-			continue;
-
-		if (vlv_raw_plane_wm_compute(crtc_state, new_plane_state))
-			dirty |= BIT(plane->id);
-	}
-
-	/*
-	 * DSPARB registers may have been reset due to the
-	 * power well being turned off. Make sure we restore
-	 * them to a consistent state even if no primary/sprite
-	 * planes are initially active.
-	 */
-	if (needs_modeset)
-		crtc_state->fifo_changed = true;
-
-	if (!dirty)
-		return 0;
-
-	/* cursor changes don't warrant a FIFO recompute */
-	if (dirty & ~BIT(PLANE_CURSOR)) {
-		const struct intel_crtc_state *old_crtc_state =
-			intel_atomic_get_old_crtc_state(state, crtc);
-		const struct vlv_fifo_state *old_fifo_state =
-			&old_crtc_state->wm.vlv.fifo_state;
-
-		ret = vlv_compute_fifo(crtc_state);
-		if (ret)
-			return ret;
-
-		if (needs_modeset ||
-		    memcmp(old_fifo_state, fifo_state,
-			   sizeof(*fifo_state)) != 0)
-			crtc_state->fifo_changed = true;
-	}
+	int level;
 
 	/* initially allow all levels */
 	wm_state->num_levels = intel_wm_num_levels(dev_priv);
@@ -1969,6 +1922,67 @@ static int vlv_compute_pipe_wm(struct intel_atomic_state *state,
 	return 0;
 }
 
+static int vlv_compute_pipe_wm(struct intel_atomic_state *state,
+			       struct intel_crtc *crtc)
+{
+	struct intel_crtc_state *crtc_state =
+		intel_atomic_get_new_crtc_state(state, crtc);
+	bool needs_modeset = drm_atomic_crtc_needs_modeset(&crtc_state->uapi);
+	const struct intel_plane_state *old_plane_state;
+	const struct intel_plane_state *new_plane_state;
+	struct intel_plane *plane;
+	unsigned int dirty = 0;
+	int i;
+
+	for_each_oldnew_intel_plane_in_state(state, plane,
+					     old_plane_state,
+					     new_plane_state, i) {
+		if (new_plane_state->hw.crtc != &crtc->base &&
+		    old_plane_state->hw.crtc != &crtc->base)
+			continue;
+
+		if (vlv_raw_plane_wm_compute(crtc_state, new_plane_state))
+			dirty |= BIT(plane->id);
+	}
+
+	/*
+	 * DSPARB registers may have been reset due to the
+	 * power well being turned off. Make sure we restore
+	 * them to a consistent state even if no primary/sprite
+	 * planes are initially active. We also force a FIFO
+	 * recomputation so that we are sure to sanitize the
+	 * FIFO setting we took over from the BIOS even if there
+	 * are no active planes on the crtc.
+	 */
+	if (needs_modeset)
+		dirty = ~0;
+
+	if (!dirty)
+		return 0;
+
+	/* cursor changes don't warrant a FIFO recompute */
+	if (dirty & ~BIT(PLANE_CURSOR)) {
+		const struct intel_crtc_state *old_crtc_state =
+			intel_atomic_get_old_crtc_state(state, crtc);
+		const struct vlv_fifo_state *old_fifo_state =
+			&old_crtc_state->wm.vlv.fifo_state;
+		const struct vlv_fifo_state *new_fifo_state =
+			&crtc_state->wm.vlv.fifo_state;
+		int ret;
+
+		ret = vlv_compute_fifo(crtc_state);
+		if (ret)
+			return ret;
+
+		if (needs_modeset ||
+		    memcmp(old_fifo_state, new_fifo_state,
+			   sizeof(*new_fifo_state)) != 0)
+			crtc_state->fifo_changed = true;
+	}
+
+	return _vlv_compute_pipe_wm(crtc_state);
+}
+
 #define VLV_FIFO(plane, value) \
 	(((value) << DSPARB_ ## plane ## _SHIFT_VLV) & DSPARB_ ## plane ## _MASK_VLV)