linux-kernel - [PATCH v2 2/3] PM / EM: Extend em_perf

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Date:   Fri, 21 May 2021 17:54:23 +0100
From:   Vincent Donnefort <vincent.donnefort@....com>
To:     peterz@...radead.org, rjw@...ysocki.net, viresh.kumar@...aro.org,
        vincent.guittot@...aro.org, qperret@...gle.com
Cc:     linux-kernel@...r.kernel.org, ionela.voinescu@....com,
        lukasz.luba@....com, dietmar.eggemann@....com,
        Vincent Donnefort <vincent.donnefort@....com>
Subject: [PATCH v2 2/3] PM / EM: Extend em_perf_domain with a flag field

Merge the current "milliwatts" option into a "flag" field. This intends to
prepare the extension of this structure for inefficient states support in
the Energy Model.

Signed-off-by: Vincent Donnefort <vincent.donnefort@....com>

diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index 757fc60..9be7bde 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -28,8 +28,7 @@ struct em_perf_state {
  * em_perf_domain - Performance domain
  * @table:		List of performance states, in ascending order
  * @nr_perf_states:	Number of performance states
- * @milliwatts:		Flag indicating the power values are in milli-Watts
- *			or some other scale.
+ * @flags:		See "em_perf_domain flags"
  * @cpus:		Cpumask covering the CPUs of the domain. It's here
  *			for performance reasons to avoid potential cache
  *			misses during energy calculations in the scheduler
@@ -44,10 +43,18 @@ struct em_perf_state {
 struct em_perf_domain {
 	struct em_perf_state *table;
 	int nr_perf_states;
-	int milliwatts;
+	int flags;
 	unsigned long cpus[];
 };
 
+/*
+ *  em_perf_domain flags:
+ *
+ *  EM_PERF_DOMAIN_MILLIWATTS: The power values are in milli-Watts or some
+ *  other scale.
+ */
+#define EM_PERF_DOMAIN_MILLIWATTS BIT(0)
+
 #define em_span_cpus(em) (to_cpumask((em)->cpus))
 
 #ifdef CONFIG_ENERGY_MODEL
diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
index c4871a8..638581c 100644
--- a/kernel/power/energy_model.c
+++ b/kernel/power/energy_model.c
@@ -55,7 +55,8 @@ DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);
 static int em_debug_units_show(struct seq_file *s, void *unused)
 {
 	struct em_perf_domain *pd = s->private;
-	char *units = pd->milliwatts ? "milliWatts" : "bogoWatts";
+	char *units = (pd->flags & EM_PERF_DOMAIN_MILLIWATTS) ?
+		"milliWatts" : "bogoWatts";
 
 	seq_printf(s, "%s\n", units);
 
@@ -341,7 +342,8 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
 	if (ret)
 		goto unlock;
 
-	dev->em_pd->milliwatts = milliwatts;
+	if (milliwatts)
+		dev->em_pd->flags |= EM_PERF_DOMAIN_MILLIWATTS;
 
 	em_debug_create_pd(dev);
 	dev_info(dev, "EM: created perf domain\n");
-- 
2.7.4