OPP: Move required opps configuration to specialized callback

The required-opps configuration is closely tied to genpd and performance
states at the moment and it is not very obvious that required-opps can
live without genpds. Though we don't support configuring required-opps
for non-genpd cases currently.

This commit aims at separating these parts, where configuring genpds
would be a special case of configuring the required-opps.

Add a specialized callback, set_required_opps(), to the opp table and
set it to different callbacks accordingly.

This shouldn't result in any functional changes for now.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/opp/core.c

@@ -935,7 +935,7 @@ static int _set_opp_bw(const struct opp_table *opp_table,
 	return 0;
 }
 
-static int _set_required_opp(struct device *dev, struct device *pd_dev,
+static int _set_performance_state(struct device *dev, struct device *pd_dev,
 				  struct dev_pm_opp *opp, int i)
 {
 	unsigned int pstate = likely(opp) ? opp->required_opps[i]->pstate : 0;
@@ -953,33 +953,20 @@ static int _set_required_opp(struct device *dev, struct device *pd_dev,
 	return ret;
 }
 
-/* This is only called for PM domain for now */
-static int _set_required_opps(struct device *dev,
-			      struct opp_table *opp_table,
-			      struct dev_pm_opp *opp, bool up)
+static int _opp_set_required_opps_generic(struct device *dev,
+	struct opp_table *opp_table, struct dev_pm_opp *opp, bool scaling_down)
+{
+	dev_err(dev, "setting required-opps isn't supported for non-genpd devices\n");
+	return -ENOENT;
+}
+
+static int _opp_set_required_opps_genpd(struct device *dev,
+	struct opp_table *opp_table, struct dev_pm_opp *opp, bool scaling_down)
 {
-	struct opp_table **required_opp_tables = opp_table->required_opp_tables;
 	struct device **genpd_virt_devs =
 		opp_table->genpd_virt_devs ? opp_table->genpd_virt_devs : &dev;
 	int i, ret = 0;
 
-	if (!required_opp_tables)
-		return 0;
-
-	/* required-opps not fully initialized yet */
-	if (lazy_linking_pending(opp_table))
-		return -EBUSY;
-
-	/*
-	 * We only support genpd's OPPs in the "required-opps" for now, as we
-	 * don't know much about other use cases. Error out if the required OPP
-	 * doesn't belong to a genpd.
-	 */
-	if (unlikely(!required_opp_tables[0]->is_genpd)) {
-		dev_err(dev, "required-opps don't belong to a genpd\n");
-		return -ENOENT;
-	}
-
 	/*
 	 * Acquire genpd_virt_dev_lock to make sure we don't use a genpd_dev
 	 * after it is freed from another thread.
@@ -987,15 +974,15 @@ static int _set_required_opps(struct device *dev,
 	mutex_lock(&opp_table->genpd_virt_dev_lock);
 
 	/* Scaling up? Set required OPPs in normal order, else reverse */
-	if (up) {
+	if (!scaling_down) {
 		for (i = 0; i < opp_table->required_opp_count; i++) {
-			ret = _set_required_opp(dev, genpd_virt_devs[i], opp, i);
+			ret = _set_performance_state(dev, genpd_virt_devs[i], opp, i);
 			if (ret)
 				break;
 		}
 	} else {
 		for (i = opp_table->required_opp_count - 1; i >= 0; i--) {
-			ret = _set_required_opp(dev, genpd_virt_devs[i], opp, i);
+			ret = _set_performance_state(dev, genpd_virt_devs[i], opp, i);
 			if (ret)
 				break;
 		}
@@ -1006,6 +993,34 @@ static int _set_required_opps(struct device *dev,
 	return ret;
 }
 
+/* This is only called for PM domain for now */
+static int _set_required_opps(struct device *dev, struct opp_table *opp_table,
+			      struct dev_pm_opp *opp, bool up)
+{
+	/* required-opps not fully initialized yet */
+	if (lazy_linking_pending(opp_table))
+		return -EBUSY;
+
+	if (opp_table->set_required_opps)
+		return opp_table->set_required_opps(dev, opp_table, opp, up);
+
+	return 0;
+}
+
+/* Update set_required_opps handler */
+void _update_set_required_opps(struct opp_table *opp_table)
+{
+	/* Already set */
+	if (opp_table->set_required_opps)
+		return;
+
+	/* All required OPPs will belong to genpd or none */
+	if (opp_table->required_opp_tables[0]->is_genpd)
+		opp_table->set_required_opps = _opp_set_required_opps_genpd;
+	else
+		opp_table->set_required_opps = _opp_set_required_opps_generic;
+}
+
 static void _find_current_opp(struct device *dev, struct opp_table *opp_table)
 {
 	struct dev_pm_opp *opp = ERR_PTR(-ENODEV);

drivers/opp/of.c

@@ -196,6 +196,8 @@ static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
 	/* Let's do the linking later on */
 	if (lazy)
 		list_add(&opp_table->lazy, &lazy_opp_tables);
+	else
+		_update_set_required_opps(opp_table);
 
 	goto put_np;
 
@@ -411,6 +413,7 @@ static void lazy_link_required_opp_table(struct opp_table *new_table)
 
 		/* All required opp-tables found, remove from lazy list */
 		if (!lazy) {
+			_update_set_required_opps(opp_table);
 			list_del_init(&opp_table->lazy);
 
 			list_for_each_entry(opp, &opp_table->opp_list, node)

drivers/opp/opp.h

@@ -184,6 +184,7 @@ enum opp_table_access {
  * @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_required_opps: Helper responsible to set required OPPs.
  * @dentry:	debugfs dentry pointer of the real device directory (not links).
  * @dentry_name: Name of the real dentry.
  *
@@ -234,6 +235,8 @@ struct opp_table {
 	bool enabled;
 	bool genpd_performance_state;
 	bool is_genpd;
+	int (*set_required_opps)(struct device *dev,
+		struct opp_table *opp_table, struct dev_pm_opp *opp, bool scaling_down);
 
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *dentry;
@@ -257,6 +260,7 @@ void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, int last_cp
 struct opp_table *_add_opp_table_indexed(struct device *dev, int index, bool getclk);
 void _put_opp_list_kref(struct opp_table *opp_table);
 void _required_opps_available(struct dev_pm_opp *opp, int count);
+void _update_set_required_opps(struct opp_table *opp_table);
 
 static inline bool lazy_linking_pending(struct opp_table *opp_table)
 {