drm/i915: Introduce intel_dbuf_slice_size()

Put the code into a function with a descriptive name. Also relocate
the code a bit help future work.

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/20210122205633.18492-4-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/intel_pm.c

@@ -4017,6 +4017,24 @@ static int intel_compute_sagv_mask(struct intel_atomic_state *state)
 	return 0;
 }
 
+static int intel_dbuf_size(struct drm_i915_private *dev_priv)
+{
+	int ddb_size = INTEL_INFO(dev_priv)->ddb_size;
+
+	drm_WARN_ON(&dev_priv->drm, ddb_size == 0);
+
+	if (INTEL_GEN(dev_priv) < 11)
+		return ddb_size - 4; /* 4 blocks for bypass path allocation */
+
+	return ddb_size;
+}
+
+static int intel_dbuf_slice_size(struct drm_i915_private *dev_priv)
+{
+	return intel_dbuf_size(dev_priv) /
+		INTEL_INFO(dev_priv)->num_supported_dbuf_slices;
+}
+
 /*
  * Calculate initial DBuf slice offset, based on slice size
  * and mask(i.e if slice size is 1024 and second slice is enabled
@@ -4038,22 +4056,11 @@ icl_get_first_dbuf_slice_offset(u32 dbuf_slice_mask,
 	return offset;
 }
 
-u16 intel_get_ddb_size(struct drm_i915_private *dev_priv)
-{
-	u16 ddb_size = INTEL_INFO(dev_priv)->ddb_size;
-	drm_WARN_ON(&dev_priv->drm, ddb_size == 0);
-
-	if (INTEL_GEN(dev_priv) < 11)
-		return ddb_size - 4; /* 4 blocks for bypass path allocation */
-
-	return ddb_size;
-}
-
 u32 skl_ddb_dbuf_slice_mask(struct drm_i915_private *dev_priv,
 			    const struct skl_ddb_entry *entry)
 {
 	u32 slice_mask = 0;
-	u16 ddb_size = intel_get_ddb_size(dev_priv);
+	u16 ddb_size = intel_dbuf_size(dev_priv);
 	u16 num_supported_slices = INTEL_INFO(dev_priv)->num_supported_dbuf_slices;
 	u16 slice_size = ddb_size / num_supported_slices;
 	u16 start_slice;
@@ -4134,9 +4141,8 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
 		return 0;
 	}
 
-	ddb_size = intel_get_ddb_size(dev_priv);
-
-	slice_size = ddb_size / INTEL_INFO(dev_priv)->num_supported_dbuf_slices;
+	ddb_size = intel_dbuf_size(dev_priv);
+	slice_size = intel_dbuf_slice_size(dev_priv);
 
 	/*
 	 * If the state doesn't change the active CRTC's or there is no

drivers/gpu/drm/i915/intel_pm.h

@@ -40,7 +40,6 @@ void skl_pipe_ddb_get_hw_state(struct intel_crtc *crtc,
 			       struct skl_ddb_entry *ddb_y,
 			       struct skl_ddb_entry *ddb_uv);
 void skl_ddb_get_hw_state(struct drm_i915_private *dev_priv);
-u16 intel_get_ddb_size(struct drm_i915_private *dev_priv);
 u32 skl_ddb_dbuf_slice_mask(struct drm_i915_private *dev_priv,
 			    const struct skl_ddb_entry *entry);
 void skl_pipe_wm_get_hw_state(struct intel_crtc *crtc,