[PATCH 5/7] PM / Domain: Implement of_dev_pm_genpd_get_performance_state()

[Viresh Kumar]

This implements of_dev_pm_genpd_get_performance_state() which can be
used from the device drivers or the OPP core to find the performance
state encoded in the "required-opp" property of a node. Different
platforms may encode the performance state differently using the OPP
table (they may simply return value of opp-hz or opp-microvolt, or apply
some algorithm on top of those values) and so a new callback is
implemented to allow platform specific drivers to convert the power
domain OPP to a performance state.

Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
 drivers/base/power/domain.c | 48 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pm_domain.h   | 11 +++++++++++
 2 files changed, 59 insertions(+)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 1ad4ad0b0de0..ef43b75982fa 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2415,6 +2415,54 @@ int of_genpd_parse_idle_states(struct device_node *dn,
 }
 EXPORT_SYMBOL_GPL(of_genpd_parse_idle_states);
 
+/**
+ * of_dev_pm_genpd_get_performance_state- Gets performance state of device's
+ * power domain corresponding to a DT node's "required-opp" property.
+ *
+ * @dev: Device for which the performance-state needs to be found.
+ * @np: DT node where the "required-opp" property is present. This can be
+ *	the device node itself (if it doesn't have an OPP table) or a node
+ *	within the OPP table of a device (if device has an OPP table).
+ * @state: Pointer to return performance state.
+ *
+ * Returns performance state corresponding to the "required-opp" property of
+ * a DT node. This calls platform specific genpd->get_performance_state()
+ * callback to translate power domain OPP to performance state.
+ *
+ * Returns performance state on success and 0 on failure.
+ */
+unsigned int of_dev_pm_genpd_get_performance_state(struct device *dev,
+						   struct device_node *np)
+{
+	struct generic_pm_domain *genpd;
+	struct dev_pm_opp *opp;
+	int state = 0;
+
+	genpd = dev_to_genpd(dev);
+	if (IS_ERR(genpd))
+		return 0;
+
+	if (unlikely(!genpd->set_performance_state))
+		return 0;
+
+	genpd_lock(genpd);
+
+	opp = of_dev_pm_opp_find_required_opp(&genpd->dev, np);
+	if (IS_ERR(opp)) {
+		state = PTR_ERR(opp);
+		goto unlock;
+	}
+
+	state = genpd->get_performance_state(genpd, opp);
+	dev_pm_opp_put(opp);
+
+unlock:
+	genpd_unlock(genpd);
+
+	return state;
+}
+EXPORT_SYMBOL_GPL(of_dev_pm_genpd_get_performance_state);
+
 #endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
 
 
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index aaacaa35005d..4edbdaa54cec 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -47,6 +47,7 @@ struct genpd_power_state {
 };
 
 struct genpd_lock_ops;
+struct dev_pm_opp;
 
 struct generic_pm_domain {
 	struct device dev;
@@ -68,6 +69,8 @@ struct generic_pm_domain {
 	unsigned int performance_state;	/* Aggregated max performance state */
 	int (*power_off)(struct generic_pm_domain *domain);
 	int (*power_on)(struct generic_pm_domain *domain);
+	unsigned int (*get_performance_state)(struct generic_pm_domain *genpd,
+					      struct dev_pm_opp *opp);
 	int (*set_performance_state)(struct generic_pm_domain *genpd,
 				     unsigned int state);
 	struct gpd_dev_ops dev_ops;
@@ -244,6 +247,8 @@ extern int of_genpd_add_subdomain(struct of_phandle_args *parent,
 extern struct generic_pm_domain *of_genpd_remove_last(struct device_node *np);
 extern int of_genpd_parse_idle_states(struct device_node *dn,
 			struct genpd_power_state **states, int *n);
+extern unsigned int of_dev_pm_genpd_get_performance_state(struct device *dev,
+				struct device_node *np);
 
 int genpd_dev_pm_attach(struct device *dev);
 #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
@@ -279,6 +284,12 @@ static inline int of_genpd_parse_idle_states(struct device_node *dn,
 	return -ENODEV;
 }
 
+static inline unsigned int of_dev_pm_genpd_get_performance_state(struct device *dev,
+					struct device_node *np)
+{
+	return -ENODEV;
+}
+
 static inline int genpd_dev_pm_attach(struct device *dev)
 {
 	return -ENODEV;
-- 
2.15.0.194.g9af6a3dea062