linux-kernel - [PATCH 2/4] opp: Track device's resources configuration status

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Date:   Thu, 13 Aug 2020 09:58:59 +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>, mka@...omium.org,
        sibis@...eaurora.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/4] opp: Track device's resources configuration status

The OPP core needs to track if the resources of devices are enabled or
configured or not, as it disables the resources when target_freq is set
to 0.

Handle that with a separate variable to make it easy to maintain.

Also note that we will unconditionally call clk_set_rate() in the case
where the resources are getting enabled again. This shouldn't have any
side effects anyway.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 drivers/opp/core.c | 37 ++++++++++++++++++-------------------
 drivers/opp/opp.h  |  2 ++
 2 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 9668ea04cc80..e8882e7fd8a5 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -888,22 +888,18 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 	}
 
 	if (unlikely(!target_freq)) {
+		ret = 0;
+
+		if (!opp_table->enabled)
+			goto put_opp_table;
+
 		/*
 		 * Some drivers need to support cases where some platforms may
 		 * have OPP table for the device, while others don't and
 		 * opp_set_rate() just needs to behave like clk_set_rate().
 		 */
-		if (!_get_opp_count(opp_table)) {
-			ret = 0;
-			goto put_opp_table;
-		}
-
-		if (!opp_table->required_opp_tables && !opp_table->regulators &&
-		    !opp_table->paths) {
-			dev_err(dev, "target frequency can't be 0\n");
-			ret = -EINVAL;
+		if (!_get_opp_count(opp_table))
 			goto put_opp_table;
-		}
 
 		ret = _set_opp_bw(opp_table, NULL, dev, true);
 		if (ret)
@@ -915,6 +911,9 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 		}
 
 		ret = _set_required_opps(dev, opp_table, NULL);
+		if (!ret)
+			opp_table->enabled = false;
+
 		goto put_opp_table;
 	}
 
@@ -933,14 +932,11 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 	old_freq = clk_get_rate(clk);
 
 	/* Return early if nothing to do */
-	if (old_freq == freq) {
-		if (!opp_table->required_opp_tables && !opp_table->regulators &&
-		    !opp_table->paths) {
-			dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do\n",
-				__func__, freq);
-			ret = 0;
-			goto put_opp_table;
-		}
+	if (opp_table->enabled && old_freq == freq) {
+		dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do\n",
+			__func__, freq);
+		ret = 0;
+		goto put_opp_table;
 	}
 
 	/*
@@ -1001,8 +997,11 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 			dev_err(dev, "Failed to set required opps: %d\n", ret);
 	}
 
-	if (!ret)
+	if (!ret) {
 		ret = _set_opp_bw(opp_table, opp, dev, false);
+		if (!ret)
+			opp_table->enabled = true;
+	}
 
 put_opp:
 	dev_pm_opp_put(opp);
diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index e51646ff279e..bd35802acc6e 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -152,6 +152,7 @@ enum opp_table_access {
  * property).
  * @paths: Interconnect path handles
  * @path_count: Number of interconnect paths
+ * @enabled: Set to true if the device's resources are enabled/configured.
  * @genpd_performance_state: Device's power domain support performance state.
  * @is_genpd: Marks if the OPP table belongs to a genpd.
  * @set_opp: Platform specific set_opp callback
@@ -198,6 +199,7 @@ struct opp_table {
 	bool regulator_enabled;
 	struct icc_path **paths;
 	unsigned int path_count;
+	bool enabled;
 	bool genpd_performance_state;
 	bool is_genpd;
 
-- 
2.14.1