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[PATCH 06/10] PM / OPP: Add dev_pm_opp_get_sharing_cpus()

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  [PATCH 06/10] PM / OPP: Add dev_pm_opp_get_sharing_cpus() Viresh Kumar <viresh.kumar@linaro.org> - 2016-04-21 11:00 +0200
    Re: [PATCH 06/10] PM / OPP: Add dev_pm_opp_get_sharing_cpus() Stephen Boyd <sboyd@codeaurora.org> - 2016-04-23 00:30 +0200
      Re: [PATCH 06/10] PM / OPP: Add dev_pm_opp_get_sharing_cpus() Viresh Kumar <viresh.kumar@linaro.org> - 2016-04-27 05:00 +0200

#1383960 — [PATCH 06/10] PM / OPP: Add dev_pm_opp_get_sharing_cpus()

OPP core allows a platform to mark OPP table as shared, when the
platform isn't using operating-points-v2 bindings.

And, so there should be a non DT way of finding out if the OPP table is
shared or not.

This patch adds dev_pm_opp_get_sharing_cpus(), which first tries to get
OPP sharing information from the opp-table (in case it is already marked
as shared), otherwise it uses the existing DT way of finding sharing
information.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/base/power/opp/cpu.c | 45 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pm_opp.h       |  6 ++++++
 2 files changed, 51 insertions(+)

diff --git a/drivers/base/power/opp/cpu.c b/drivers/base/power/opp/cpu.c
index 55cbf9bd8707..9c4eb90759fb 100644
--- a/drivers/base/power/opp/cpu.c
+++ b/drivers/base/power/opp/cpu.c
@@ -329,3 +329,48 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_set_sharing_cpus);
+
+/**
+ * dev_pm_opp_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with @cpu_dev
+ * @cpu_dev:	CPU device for which we do this operation
+ * @cpumask:	cpumask to update with information of sharing CPUs
+ *
+ * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
+ *
+ * Returns -ENODEV if OPP table isn't already present.
+ *
+ * Locking: The internal opp_table and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ */
+int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
+{
+	struct opp_device *opp_dev;
+	struct opp_table *opp_table;
+	int ret = 0;
+
+	mutex_lock(&opp_table_lock);
+
+	opp_table = _find_opp_table(cpu_dev);
+	if (IS_ERR(opp_table)) {
+		ret = PTR_ERR(opp_table);
+		goto unlock;
+	}
+
+	cpumask_clear(cpumask);
+
+	if (opp_table->shared_opp) {
+		list_for_each_entry(opp_dev, &opp_table->dev_list, node)
+			cpumask_set_cpu(opp_dev->dev->id, cpumask);
+	} else {
+		cpumask_set_cpu(cpu_dev->id, cpumask);
+	}
+
+unlock:
+	mutex_unlock(&opp_table_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_sharing_cpus);
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 5b6ad31403a5..d6effc931013 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -66,6 +66,7 @@ int dev_pm_opp_set_regulator(struct device *dev, const char *name);
 void dev_pm_opp_put_regulator(struct device *dev);
 int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq);
 int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask);
+int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask);
 #else
 static inline unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 {
@@ -184,6 +185,11 @@ static inline int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, cpumask_va
 	return -ENOSYS;
 }
 
+static inline int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
+{
+	return -ENOSYS;
+}
+
 #endif		/* CONFIG_PM_OPP */
 
 #if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
-- 
2.7.1.410.g6faf27b

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#1385509

On 04/21, Viresh Kumar wrote:
> diff --git a/drivers/base/power/opp/cpu.c b/drivers/base/power/opp/cpu.c
> index 55cbf9bd8707..9c4eb90759fb 100644
> --- a/drivers/base/power/opp/cpu.c
> +++ b/drivers/base/power/opp/cpu.c
> @@ -329,3 +329,48 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
>  	return ret;
>  }
>  EXPORT_SYMBOL_GPL(dev_pm_opp_set_sharing_cpus);
> +
> +/**
> + * dev_pm_opp_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with @cpu_dev
> + * @cpu_dev:	CPU device for which we do this operation
> + * @cpumask:	cpumask to update with information of sharing CPUs
> + *
> + * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
> + *
> + * Returns -ENODEV if OPP table isn't already present.
> + *
> + * Locking: The internal opp_table and opp structures are RCU protected.
> + * Hence this function internally uses RCU updater strategy with mutex locks
> + * to keep the integrity of the internal data structures. Callers should ensure
> + * that this function is *NOT* called under RCU protection or in contexts where
> + * mutex cannot be locked.
> + */
> +int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)

Is there a reason we use cpumask_var_t instead of struct cpumask *
here? My understanding is that cpumask_var_t is for stack
declarations.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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#1388612

On 22-04-16, 15:21, Stephen Boyd wrote:
> On 04/21, Viresh Kumar wrote:
> > diff --git a/drivers/base/power/opp/cpu.c b/drivers/base/power/opp/cpu.c
> > index 55cbf9bd8707..9c4eb90759fb 100644
> > --- a/drivers/base/power/opp/cpu.c
> > +++ b/drivers/base/power/opp/cpu.c
> > @@ -329,3 +329,48 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
> >  	return ret;
> >  }
> >  EXPORT_SYMBOL_GPL(dev_pm_opp_set_sharing_cpus);
> > +
> > +/**
> > + * dev_pm_opp_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with @cpu_dev
> > + * @cpu_dev:	CPU device for which we do this operation
> > + * @cpumask:	cpumask to update with information of sharing CPUs
> > + *
> > + * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
> > + *
> > + * Returns -ENODEV if OPP table isn't already present.
> > + *
> > + * Locking: The internal opp_table and opp structures are RCU protected.
> > + * Hence this function internally uses RCU updater strategy with mutex locks
> > + * to keep the integrity of the internal data structures. Callers should ensure
> > + * that this function is *NOT* called under RCU protection or in contexts where
> > + * mutex cannot be locked.
> > + */
> > +int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
> 
> Is there a reason we use cpumask_var_t instead of struct cpumask *
> here? My understanding is that cpumask_var_t is for stack
> declarations.

Just because we have been using that *consistently* everywhere in cpufreq and
OPP core.

I am fine with cpumask * as well, but we should be consistent.

So, I will keep it cpumask_var_t for this patch, and lets see if we want to
change all occurrences of the same in cpufreq and OPP core.

Sounds reasonable ?

-- 
viresh

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