linux-kernel - [PATCH 1/2] opp: Not all power-domains are scalable

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Message-Id: <90ba3941b56e50ea5548dd1e90bf3bcd8c9da4fe.1563358721.git.viresh.kumar@linaro.org>
Date:   Wed, 17 Jul 2019 15:49:46 +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 Wysocki <rjw@...ysocki.net>, niklas.cassel@...aro.org,
        Rajendra Nayak <rnayak@...eaurora.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] opp: Not all power-domains are scalable

A device may have multiple power-domains and not all of them may be
scalable (i.e. support performance states). But
dev_pm_opp_attach_genpd() doesn't take that into account currently.

Fix that by not verifying the names argument with "power-domain-names"
DT property and finding the index into the required-opps array. The
names argument will anyway get verified later on when we call
dev_pm_domain_attach_by_name().

Fixes: 6319aee10e53 ("opp: Attach genpds to devices from within OPP core")
Reported-by: Rajendra Nayak <rnayak@...eaurora.org>
Tested-by: Rajendra Nayak <rnayak@...eaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 drivers/opp/core.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 2958cc7bbb58..4e2a81698cd2 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1788,12 +1788,15 @@ static void _opp_detach_genpd(struct opp_table *opp_table)
  *
  * This helper needs to be called once with a list of all genpd to attach.
  * Otherwise the original device structure will be used instead by the OPP core.
+ *
+ * The order of entries in the names array must match the order in which
+ * "required-opps" are added in DT.
  */
 struct opp_table *dev_pm_opp_attach_genpd(struct device *dev, const char **names)
 {
 	struct opp_table *opp_table;
 	struct device *virt_dev;
-	int index, ret = -EINVAL;
+	int index = 0, ret = -EINVAL;
 	const char **name = names;
 
 	opp_table = dev_pm_opp_get_opp_table(dev);
@@ -1819,14 +1822,6 @@ struct opp_table *dev_pm_opp_attach_genpd(struct device *dev, const char **names
 		goto unlock;
 
 	while (*name) {
-		index = of_property_match_string(dev->of_node,
-						 "power-domain-names", *name);
-		if (index < 0) {
-			dev_err(dev, "Failed to find power domain: %s (%d)\n",
-				*name, index);
-			goto err;
-		}
-
 		if (index >= opp_table->required_opp_count) {
 			dev_err(dev, "Index can't be greater than required-opp-count - 1, %s (%d : %d)\n",
 				*name, opp_table->required_opp_count, index);
@@ -1847,6 +1842,7 @@ struct opp_table *dev_pm_opp_attach_genpd(struct device *dev, const char **names
 		}
 
 		opp_table->genpd_virt_devs[index] = virt_dev;
+		index++;
 		name++;
 	}
 
-- 
2.21.0.rc0.269.g1a574e7a288b