linux-kernel - [PATCH v8 12/23] PM: EM: Add em_perf_state_from

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Message-Id: <20240208115557.1273962-13-lukasz.luba@arm.com>
Date: Thu,  8 Feb 2024 11:55:46 +0000
From: Lukasz Luba <lukasz.luba@....com>
To: linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org,
	rafael@...nel.org
Cc: lukasz.luba@....com,
	dietmar.eggemann@....com,
	rui.zhang@...el.com,
	amit.kucheria@...durent.com,
	amit.kachhap@...il.com,
	daniel.lezcano@...aro.org,
	viresh.kumar@...aro.org,
	len.brown@...el.com,
	pavel@....cz,
	mhiramat@...nel.org,
	qyousef@...alina.io,
	wvw@...gle.com,
	xuewen.yan94@...il.com
Subject: [PATCH v8 12/23] PM: EM: Add em_perf_state_from_pd() to get performance states table

Introduce a wrapper to get the performance states table of the performance
domain. The function should be called within the RCU read critical
section.

Reviewed-by: Dietmar Eggemann <dietmar.eggemann@....com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@....com>
Signed-off-by: Lukasz Luba <lukasz.luba@....com>
---
 include/linux/energy_model.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index 324a3a8e0a2d..158dad6ea313 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -338,6 +338,23 @@ static inline int em_pd_nr_perf_states(struct em_perf_domain *pd)
 	return pd->nr_perf_states;
 }
 
+/**
+ * em_perf_state_from_pd() - Get the performance states table of perf.
+ *				domain
+ * @pd		: performance domain for which this must be done
+ *
+ * To use this function the rcu_read_lock() should be hold. After the usage
+ * of the performance states table is finished, the rcu_read_unlock() should
+ * be called.
+ *
+ * Return: the pointer to performance states table of the performance domain
+ */
+static inline
+struct em_perf_state *em_perf_state_from_pd(struct em_perf_domain *pd)
+{
+	return rcu_dereference(pd->em_table)->state;
+}
+
 #else
 struct em_data_callback {};
 #define EM_ADV_DATA_CB(_active_power_cb, _cost_cb) { }
@@ -384,6 +401,11 @@ int em_dev_update_perf_domain(struct device *dev,
 {
 	return -EINVAL;
 }
+static inline
+struct em_perf_state *em_perf_state_from_pd(struct em_perf_domain *pd)
+{
+	return NULL;
+}
 #endif
 
 #endif
-- 
2.25.1