drm/i915: Introduce skl_ddb_entry_for_slices()

Generalize icl_get_first_dbuf_slice_offset() into something that
just gives us the start+end of the dbuf chunk covered by the
specified slices as a standard ddb entry. Initial idea was to use
it during readout as well, but we shall see.

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/20210122205633.18492-5-ville.syrjala@linux.intel.com

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 2b53e50..b88429b 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4035,25 +4035,23 @@ static int intel_dbuf_slice_size(struct drm_i915_private *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
- * offset would be 1024)
- */
-static unsigned int
-icl_get_first_dbuf_slice_offset(u32 dbuf_slice_mask,
-                               u32 slice_size,
-                               u32 ddb_size)
+static void
+skl_ddb_entry_for_slices(struct drm_i915_private *dev_priv, u8 slice_mask,
+                        struct skl_ddb_entry *ddb)
 {
-       unsigned int offset = 0;
+       int slice_size = intel_dbuf_slice_size(dev_priv);
 
-       if (!dbuf_slice_mask)
-               return 0;
+       if (!slice_mask) {
+               ddb->start = 0;
+               ddb->end = 0;
+               return;
+       }
 
-       offset = (ffs(dbuf_slice_mask) - 1) * slice_size;
+       ddb->start = (ffs(slice_mask) - 1) * slice_size;
+       ddb->end = fls(slice_mask) * slice_size;
 
-       WARN_ON(offset >= ddb_size);
-       return offset;
+       WARN_ON(ddb->start >= ddb->end);
+       WARN_ON(ddb->end > intel_dbuf_size(dev_priv));
 }
 
 u32 skl_ddb_dbuf_slice_mask(struct drm_i915_private *dev_priv,
@@ -4123,12 +4121,10 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
        const struct intel_dbuf_state *old_dbuf_state =
                intel_atomic_get_old_dbuf_state(intel_state);
        u8 active_pipes = new_dbuf_state->active_pipes;
-       u16 ddb_size;
+       struct skl_ddb_entry ddb_slices;
        u32 ddb_range_size;
        u32 i;
        u32 dbuf_slice_mask;
-       u32 offset;
-       u32 slice_size;
        u32 total_slice_mask;
        u32 start, end;
        int ret;
@@ -4141,9 +4137,6 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
                return 0;
        }
 
-       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
         * modeset request, then there's no need to recalculate;
@@ -4169,20 +4162,8 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
         */
        dbuf_slice_mask = skl_compute_dbuf_slices(for_crtc, active_pipes);
 
-       /*
-        * Figure out at which DBuf slice we start, i.e if we start at Dbuf S2
-        * and slice size is 1024, the offset would be 1024
-        */
-       offset = icl_get_first_dbuf_slice_offset(dbuf_slice_mask,
-                                                slice_size, ddb_size);
-
-       /*
-        * Figure out total size of allowed DBuf slices, which is basically
-        * a number of allowed slices for that pipe multiplied by slice size.
-        * Inside of this
-        * range ddb entries are still allocated in proportion to display width.
-        */
-       ddb_range_size = hweight8(dbuf_slice_mask) * slice_size;
+       skl_ddb_entry_for_slices(dev_priv, dbuf_slice_mask, &ddb_slices);
+       ddb_range_size = skl_ddb_entry_size(&ddb_slices);
 
        total_slice_mask = dbuf_slice_mask;
        for_each_new_intel_crtc_in_state(intel_state, crtc, crtc_state, i) {
@@ -4239,8 +4220,8 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
        start = ddb_range_size * weight_before_pipe / total_weight;
        end = ddb_range_size * (weight_before_pipe + pipe_weight) / total_weight;
 
-       alloc->start = offset + start;
-       alloc->end = offset + end;
+       alloc->start = ddb_slices.start + start;
+       alloc->end = ddb_slices.start + end;
 
        drm_dbg_kms(&dev_priv->drm,
                    "[CRTC:%d:%s] dbuf slices 0x%x, ddb (%d - %d), active pipes 0x%x\n",