drm/i915: Allow !join_mbus cases for adlp+ dbuf configuration

Reintroduce the !join_mbus single pipe cases for adlp+.

Due to the mbus relative dbuf offsets in PLANE_BUF_CFG we
need to know the actual slices used by the pipe when doing
readout, even when mbus joining isn't enabled. Accurate
readout will be needed to properly sanitize invalid BIOS
dbuf configurations.

This will also make it much easier to play around with the
!join_mbus configs for testin/workaround purposes.

Cc: <stable@vger.kernel.org> # v5.14+
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220204141818.1900-1-ville.syrjala@linux.intel.comReviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -4695,6 +4695,10 @@ static const struct dbuf_slice_conf_entry dg2_allowed_dbufs[] = {
 };
 
 static const struct dbuf_slice_conf_entry adlp_allowed_dbufs[] = {
+	/*
+	 * Keep the join_mbus cases first so check_mbus_joined()
+	 * will prefer them over the !join_mbus cases.
+	 */
 	{
 		.active_pipes = BIT(PIPE_A),
 		.dbuf_mask = {
@@ -4709,6 +4713,20 @@ static const struct dbuf_slice_conf_entry adlp_allowed_dbufs[] = {
 		},
 		.join_mbus = true,
 	},
+	{
+		.active_pipes = BIT(PIPE_A),
+		.dbuf_mask = {
+			[PIPE_A] = BIT(DBUF_S1) | BIT(DBUF_S2),
+		},
+		.join_mbus = false,
+	},
+	{
+		.active_pipes = BIT(PIPE_B),
+		.dbuf_mask = {
+			[PIPE_B] = BIT(DBUF_S3) | BIT(DBUF_S4),
+		},
+		.join_mbus = false,
+	},
 	{
 		.active_pipes = BIT(PIPE_A) | BIT(PIPE_B),
 		.dbuf_mask = {
@@ -4825,13 +4843,14 @@ static bool adlp_check_mbus_joined(u8 active_pipes)
 	return check_mbus_joined(active_pipes, adlp_allowed_dbufs);
 }
 
-static u8 compute_dbuf_slices(enum pipe pipe, u8 active_pipes,
+static u8 compute_dbuf_slices(enum pipe pipe, u8 active_pipes, bool join_mbus,
 			      const struct dbuf_slice_conf_entry *dbuf_slices)
 {
 	int i;
 
 	for (i = 0; i < dbuf_slices[i].active_pipes; i++) {
-		if (dbuf_slices[i].active_pipes == active_pipes)
+		if (dbuf_slices[i].active_pipes == active_pipes &&
+		    dbuf_slices[i].join_mbus == join_mbus)
 			return dbuf_slices[i].dbuf_mask[pipe];
 	}
 	return 0;
@@ -4842,7 +4861,7 @@ static u8 compute_dbuf_slices(enum pipe pipe, u8 active_pipes,
  * returns correspondent DBuf slice mask as stated in BSpec for particular
  * platform.
  */
-static u8 icl_compute_dbuf_slices(enum pipe pipe, u8 active_pipes)
+static u8 icl_compute_dbuf_slices(enum pipe pipe, u8 active_pipes, bool join_mbus)
 {
 	/*
 	 * FIXME: For ICL this is still a bit unclear as prev BSpec revision
@@ -4856,37 +4875,41 @@ static u8 icl_compute_dbuf_slices(enum pipe pipe, u8 active_pipes)
 	 * still here - we will need it once those additional constraints
 	 * pop up.
 	 */
-	return compute_dbuf_slices(pipe, active_pipes, icl_allowed_dbufs);
+	return compute_dbuf_slices(pipe, active_pipes, join_mbus,
+				   icl_allowed_dbufs);
 }
 
-static u8 tgl_compute_dbuf_slices(enum pipe pipe, u8 active_pipes)
+static u8 tgl_compute_dbuf_slices(enum pipe pipe, u8 active_pipes, bool join_mbus)
 {
-	return compute_dbuf_slices(pipe, active_pipes, tgl_allowed_dbufs);
+	return compute_dbuf_slices(pipe, active_pipes, join_mbus,
+				   tgl_allowed_dbufs);
 }
 
-static u32 adlp_compute_dbuf_slices(enum pipe pipe, u32 active_pipes)
+static u8 adlp_compute_dbuf_slices(enum pipe pipe, u8 active_pipes, bool join_mbus)
 {
-	return compute_dbuf_slices(pipe, active_pipes, adlp_allowed_dbufs);
+	return compute_dbuf_slices(pipe, active_pipes, join_mbus,
+				   adlp_allowed_dbufs);
 }
 
-static u32 dg2_compute_dbuf_slices(enum pipe pipe, u32 active_pipes)
+static u8 dg2_compute_dbuf_slices(enum pipe pipe, u8 active_pipes, bool join_mbus)
 {
-	return compute_dbuf_slices(pipe, active_pipes, dg2_allowed_dbufs);
+	return compute_dbuf_slices(pipe, active_pipes, join_mbus,
+				   dg2_allowed_dbufs);
 }
 
-static u8 skl_compute_dbuf_slices(struct intel_crtc *crtc, u8 active_pipes)
+static u8 skl_compute_dbuf_slices(struct intel_crtc *crtc, u8 active_pipes, bool join_mbus)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	enum pipe pipe = crtc->pipe;
 
 	if (IS_DG2(dev_priv))
-		return dg2_compute_dbuf_slices(pipe, active_pipes);
+		return dg2_compute_dbuf_slices(pipe, active_pipes, join_mbus);
 	else if (IS_ALDERLAKE_P(dev_priv))
-		return adlp_compute_dbuf_slices(pipe, active_pipes);
+		return adlp_compute_dbuf_slices(pipe, active_pipes, join_mbus);
 	else if (DISPLAY_VER(dev_priv) == 12)
-		return tgl_compute_dbuf_slices(pipe, active_pipes);
+		return tgl_compute_dbuf_slices(pipe, active_pipes, join_mbus);
 	else if (DISPLAY_VER(dev_priv) == 11)
-		return icl_compute_dbuf_slices(pipe, active_pipes);
+		return icl_compute_dbuf_slices(pipe, active_pipes, join_mbus);
 	/*
 	 * For anything else just return one slice yet.
 	 * Should be extended for other platforms.
@@ -6139,11 +6162,16 @@ skl_compute_ddb(struct intel_atomic_state *state)
 			return ret;
 	}
 
+	if (IS_ALDERLAKE_P(dev_priv))
+		new_dbuf_state->joined_mbus =
+			adlp_check_mbus_joined(new_dbuf_state->active_pipes);
+
 	for_each_intel_crtc(&dev_priv->drm, crtc) {
 		enum pipe pipe = crtc->pipe;
 
 		new_dbuf_state->slices[pipe] =
-			skl_compute_dbuf_slices(crtc, new_dbuf_state->active_pipes);
+			skl_compute_dbuf_slices(crtc, new_dbuf_state->active_pipes,
+						new_dbuf_state->joined_mbus);
 
 		if (old_dbuf_state->slices[pipe] == new_dbuf_state->slices[pipe])
 			continue;
@@ -6155,9 +6183,6 @@ skl_compute_ddb(struct intel_atomic_state *state)
 
 	new_dbuf_state->enabled_slices = intel_dbuf_enabled_slices(new_dbuf_state);
 
-	if (IS_ALDERLAKE_P(dev_priv))
-		new_dbuf_state->joined_mbus = adlp_check_mbus_joined(new_dbuf_state->active_pipes);
-
 	if (old_dbuf_state->enabled_slices != new_dbuf_state->enabled_slices ||
 	    old_dbuf_state->joined_mbus != new_dbuf_state->joined_mbus) {
 		ret = intel_atomic_serialize_global_state(&new_dbuf_state->base);
@@ -6658,7 +6683,8 @@ void skl_wm_get_hw_state(struct drm_i915_private *dev_priv)
 		}
 
 		dbuf_state->slices[pipe] =
-			skl_compute_dbuf_slices(crtc, dbuf_state->active_pipes);
+			skl_compute_dbuf_slices(crtc, dbuf_state->active_pipes,
+						dbuf_state->joined_mbus);
 
 		dbuf_state->weight[pipe] = intel_crtc_ddb_weight(crtc_state);