linux-kernel - [PATCH 1/2] OPP: pstate is only valid for genpd OPP tables

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Date:   Wed, 14 Jun 2023 16:07:25 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     Viresh Kumar <viresh.kumar@...aro.org>, linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] OPP: pstate is only valid for genpd OPP tables

It is not very clear right now that the `pstate` field is only valid for
genpd OPP tables and not consumer tables. And there is no checking for
the same at various places.

Add checks in place to verify that and make it clear to the reader.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 drivers/opp/core.c    | 18 ++++++++++++++++--
 drivers/opp/debugfs.c |  4 +++-
 drivers/opp/of.c      |  6 ++++++
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 7290168ec806..bfb012f5383c 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -227,16 +227,24 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_level);
 unsigned int dev_pm_opp_get_required_pstate(struct dev_pm_opp *opp,
 					    unsigned int index)
 {
+	struct opp_table *opp_table = opp->opp_table;
+
 	if (IS_ERR_OR_NULL(opp) || !opp->available ||
-	    index >= opp->opp_table->required_opp_count) {
+	    index >= opp_table->required_opp_count) {
 		pr_err("%s: Invalid parameters\n", __func__);
 		return 0;
 	}
 
 	/* required-opps not fully initialized yet */
-	if (lazy_linking_pending(opp->opp_table))
+	if (lazy_linking_pending(opp_table))
 		return 0;
 
+	/* The required OPP table must belong to a genpd */
+	if (unlikely(!opp_table->required_opp_tables[index]->is_genpd)) {
+		pr_err("%s: Performance state is only valid for genpds.\n", __func__);
+		return 0;
+	}
+
 	return opp->required_opps[index]->pstate;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_required_pstate);
@@ -2686,6 +2694,12 @@ int dev_pm_opp_xlate_performance_state(struct opp_table *src_table,
 	int dest_pstate = -EINVAL;
 	int i;
 
+	/* Both OPP tables must belong to genpds */
+	if (unlikely(!src_table->is_genpd || !dst_table->is_genpd)) {
+		pr_err("%s: Performance state is only valid for genpds.\n", __func__);
+		return -EINVAL;
+	}
+
 	/*
 	 * Normally the src_table will have the "required_opps" property set to
 	 * point to one of the OPPs in the dst_table, but in some cases the
diff --git a/drivers/opp/debugfs.c b/drivers/opp/debugfs.c
index 2c7fb683441e..0cc21e2b42ff 100644
--- a/drivers/opp/debugfs.c
+++ b/drivers/opp/debugfs.c
@@ -152,11 +152,13 @@ void opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table)
 	debugfs_create_bool("dynamic", S_IRUGO, d, &opp->dynamic);
 	debugfs_create_bool("turbo", S_IRUGO, d, &opp->turbo);
 	debugfs_create_bool("suspend", S_IRUGO, d, &opp->suspend);
-	debugfs_create_u32("performance_state", S_IRUGO, d, &opp->pstate);
 	debugfs_create_u32("level", S_IRUGO, d, &opp->level);
 	debugfs_create_ulong("clock_latency_ns", S_IRUGO, d,
 			     &opp->clock_latency_ns);
 
+	if (opp_table->is_genpd)
+		debugfs_create_u32("performance_state", S_IRUGO, d, &opp->pstate);
+
 	opp->of_name = of_node_full_name(opp->np);
 	debugfs_create_str("of_name", S_IRUGO, d, (char **)&opp->of_name);
 
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 943c7fb7402b..e23ce6e78eb6 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -1392,6 +1392,12 @@ int of_get_required_opp_performance_state(struct device_node *np, int index)
 		goto put_required_np;
 	}
 
+	/* The OPP tables must belong to a genpd */
+	if (unlikely(!opp_table->is_genpd)) {
+		pr_err("%s: Performance state is only valid for genpds.\n", __func__);
+		goto put_required_np;
+	}
+
 	opp = _find_opp_of_np(opp_table, required_np);
 	if (opp) {
 		pstate = opp->pstate;
-- 
2.31.1.272.g89b43f80a514