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 <ulf.hansson@linaro.org>
Tested-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index e08375ed50aa712f59b3110772029d933080cffc..4f1ca84d9ed03454e0a951f993294384e8b3ecf0 100644 (file)
--- 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
index 5a7e294e56b701bd0997e956693a05dd23b9de1f..f9f0b22bccbb439d23370139f91d5236f07edf5a 100644 (file)
--- 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;