OPP: Don't set OPP recursively for a parent genpd

Like other frameworks (clk, regulator, etc.) genpd core too takes care of propagation to performance state to parent genpds. The OPP core shouldn't attempt the same, or it may result in undefined behavior. Add checks at various places to take care of the same. Reviewed-by: Ulf Hansson <[email protected]> Tested-by: Stephan Gerhold <[email protected]> Signed-off-by: Viresh Kumar <[email protected]>
gatlinnewhouse · Nov 28, 2023 · 9251414 · 9251414
1 parent e37440e
commit 9251414
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Showing 2 changed files with 20 additions and 3 deletions.
diff --git a/drivers/opp/core.c b/drivers/opp/core.c
@@ -2392,6 +2392,12 @@ static int _opp_attach_genpd(struct opp_table *opp_table, struct device *dev,
 		return -EINVAL;
 	}
 
+	/* Genpd core takes care of propagation to parent genpd */
+	if (opp_table->is_genpd) {
+		dev_err(dev, "%s: Operation not supported for genpds\n", __func__);
+		return -EOPNOTSUPP;
+	}
+
 	/* Checking only the first one is enough ? */
 	if (opp_table->required_devs[0])
 		return 0;
@@ -2453,8 +2459,16 @@ static int _opp_set_required_devs(struct opp_table *opp_table,
 	if (opp_table->required_devs[0])
 		return 0;
 
-	for (i = 0; i < opp_table->required_opp_count; i++)
+	for (i = 0; i < opp_table->required_opp_count; i++) {
+		/* Genpd core takes care of propagation to parent genpd */
+		if (required_devs[i] && opp_table->is_genpd &&
+		    opp_table->required_opp_tables[i]->is_genpd) {
+			dev_err(dev, "%s: Operation not supported for genpds\n", __func__);
+			return -EOPNOTSUPP;
+		}
+
 		opp_table->required_devs[i] = required_devs[i];
+	}
 
 	return 0;
 }

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
@@ -339,8 +339,11 @@ static int _link_required_opps(struct dev_pm_opp *opp, struct opp_table *opp_tab
 	 */
 	if (required_table->is_genpd && opp_table->required_opp_count == 1 &&
 	    !opp_table->required_devs[0]) {
-		if (!WARN_ON(opp->level != OPP_LEVEL_UNSET))
-			opp->level = opp->required_opps[0]->level;
+		/* Genpd core takes care of propagation to parent genpd */
+		if (!opp_table->is_genpd) {
+			if (!WARN_ON(opp->level != OPP_LEVEL_UNSET))
+				opp->level = opp->required_opps[0]->level;
+		}
 	}
 
 	return 0;