drm/i915: Extract intel_crtc_dbuf_weights()

Extract the code to calculate the weights used to chunk up the dbuf
between pipes. There's still extra stuff in there that shouldn't be
there and must be moved out, but that requires a bit more state to
be tracked in the dbuf state.

v2: Keep crtc_state->wm.skl.ddb
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210122205633.18492-7-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/intel_pm.c

@@ -4103,63 +4103,35 @@ static unsigned int intel_crtc_ddb_weight(const struct intel_crtc_state *crtc_st
 static u8 skl_compute_dbuf_slices(struct intel_crtc *crtc,
 				  u8 active_pipes);
 
-static int
-skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
-				   struct intel_crtc_state *crtc_state,
-				   const u64 total_data_rate,
-				   struct skl_ddb_entry *alloc, /* out */
-				   int *num_active /* out */)
+static int intel_crtc_dbuf_weights(struct intel_atomic_state *state,
+				   struct intel_crtc *for_crtc,
+				   unsigned int *weight_start,
+				   unsigned int *weight_end,
+				   unsigned int *weight_total)
 {
-	struct drm_atomic_state *state = crtc_state->uapi.state;
-	struct intel_atomic_state *intel_state = to_intel_atomic_state(state);
-	struct intel_crtc *for_crtc = to_intel_crtc(crtc_state->uapi.crtc);
-	struct intel_crtc *crtc;
-	unsigned int pipe_weight = 0, total_weight = 0, weight_before_pipe = 0;
-	enum pipe for_pipe = for_crtc->pipe;
-	struct intel_dbuf_state *new_dbuf_state =
-		intel_atomic_get_new_dbuf_state(intel_state);
 	const struct intel_dbuf_state *old_dbuf_state =
-		intel_atomic_get_old_dbuf_state(intel_state);
+		intel_atomic_get_old_dbuf_state(state);
+	struct intel_dbuf_state *new_dbuf_state =
+		intel_atomic_get_new_dbuf_state(state);
 	u8 active_pipes = new_dbuf_state->active_pipes;
-	struct skl_ddb_entry ddb_slices;
-	u32 ddb_range_size;
-	u32 i;
-	u32 dbuf_slice_mask;
-	u32 total_slice_mask;
-	u32 start, end;
-	int ret;
-
-	*num_active = hweight8(active_pipes);
-
-	if (!crtc_state->hw.active) {
-		alloc->start = 0;
-		alloc->end = 0;
-		crtc_state->wm.skl.ddb = *alloc;
-		return 0;
-	}
-
-	/*
-	 * If the state doesn't change the active CRTC's or there is no
-	 * modeset request, then there's no need to recalculate;
-	 * the existing pipe allocation limits should remain unchanged.
-	 * Note that we're safe from racing commits since any racing commit
-	 * that changes the active CRTC list or do modeset would need to
-	 * grab _all_ crtc locks, including the one we currently hold.
-	 */
-	if (old_dbuf_state->active_pipes == new_dbuf_state->active_pipes &&
-	    !dev_priv->wm.distrust_bios_wm)
-		return 0;
+	enum pipe for_pipe = for_crtc->pipe;
+	const struct intel_crtc_state *crtc_state;
+	struct intel_crtc *crtc;
+	u8 dbuf_slice_mask;
+	u8 total_slice_mask;
+	int i, ret;
 
 	/*
 	 * Get allowed DBuf slices for correspondent pipe and platform.
 	 */
 	dbuf_slice_mask = skl_compute_dbuf_slices(for_crtc, active_pipes);
+	total_slice_mask = dbuf_slice_mask;
 
-	skl_ddb_entry_for_slices(dev_priv, dbuf_slice_mask, &ddb_slices);
-	ddb_range_size = skl_ddb_entry_size(&ddb_slices);
+	*weight_start = 0;
+	*weight_end = 0;
+	*weight_total = 0;
 
-	total_slice_mask = dbuf_slice_mask;
-	for_each_new_intel_crtc_in_state(intel_state, crtc, crtc_state, i) {
+	for_each_new_intel_crtc_in_state(state, crtc, crtc_state, i) {
 		enum pipe pipe = crtc->pipe;
 		unsigned int weight;
 		u8 pipe_dbuf_slice_mask;
@@ -4190,12 +4162,14 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
 			continue;
 
 		weight = intel_crtc_ddb_weight(crtc_state);
-		total_weight += weight;
+		*weight_total += weight;
 
-		if (pipe < for_pipe)
-			weight_before_pipe += weight;
-		else if (pipe == for_pipe)
-			pipe_weight = weight;
+		if (pipe < for_pipe) {
+			*weight_start += weight;
+			*weight_end += weight;
+		} else if (pipe == for_pipe) {
+			*weight_end += weight;
+		}
 	}
 
 	/*
@@ -4210,8 +4184,67 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
 			return ret;
 	}
 
-	start = ddb_range_size * weight_before_pipe / total_weight;
-	end = ddb_range_size * (weight_before_pipe + pipe_weight) / total_weight;
+	return 0;
+}
+
+static int
+skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
+				   struct intel_crtc_state *crtc_state,
+				   const u64 total_data_rate,
+				   struct skl_ddb_entry *alloc, /* out */
+				   int *num_active /* out */)
+{
+	struct intel_atomic_state *state =
+		to_intel_atomic_state(crtc_state->uapi.state);
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	unsigned int weight_start, weight_end, weight_total;
+	const struct intel_dbuf_state *old_dbuf_state =
+		intel_atomic_get_old_dbuf_state(state);
+	struct intel_dbuf_state *new_dbuf_state =
+		intel_atomic_get_new_dbuf_state(state);
+	u8 active_pipes = new_dbuf_state->active_pipes;
+	struct skl_ddb_entry ddb_slices;
+	u32 ddb_range_size;
+	u32 dbuf_slice_mask;
+	u32 start, end;
+	int ret;
+
+	*num_active = hweight8(active_pipes);
+
+	if (!crtc_state->hw.active) {
+		alloc->start = 0;
+		alloc->end = 0;
+		crtc_state->wm.skl.ddb = *alloc;
+		return 0;
+	}
+
+	/*
+	 * If the state doesn't change the active CRTC's or there is no
+	 * modeset request, then there's no need to recalculate;
+	 * the existing pipe allocation limits should remain unchanged.
+	 * Note that we're safe from racing commits since any racing commit
+	 * that changes the active CRTC list or do modeset would need to
+	 * grab _all_ crtc locks, including the one we currently hold.
+	 */
+	if (old_dbuf_state->active_pipes == new_dbuf_state->active_pipes &&
+	    !dev_priv->wm.distrust_bios_wm)
+		return 0;
+
+	/*
+	 * Get allowed DBuf slices for correspondent pipe and platform.
+	 */
+	dbuf_slice_mask = skl_compute_dbuf_slices(crtc, active_pipes);
+
+	skl_ddb_entry_for_slices(dev_priv, dbuf_slice_mask, &ddb_slices);
+	ddb_range_size = skl_ddb_entry_size(&ddb_slices);
+
+	ret = intel_crtc_dbuf_weights(state, crtc,
+				      &weight_start, &weight_end, &weight_total);
+	if (ret)
+		return ret;
+
+	start = ddb_range_size * weight_start / weight_total;
+	end = ddb_range_size * weight_end / weight_total;
 
 	alloc->start = ddb_slices.start + start;
 	alloc->end = ddb_slices.start + end;
@@ -4219,7 +4252,7 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
 
 	drm_dbg_kms(&dev_priv->drm,
 		    "[CRTC:%d:%s] dbuf slices 0x%x, ddb (%d - %d), active pipes 0x%x\n",
-		    for_crtc->base.base.id, for_crtc->base.name,
+		    crtc->base.base.id, crtc->base.name,
 		    dbuf_slice_mask, alloc->start, alloc->end, active_pipes);
 
 	return 0;