Re: [PATCH V3 12/16] PM / OPP: add dev_pm_opp_is_turbo() helper

Viresh Kumar
2015-07-31T06:17:16Z

On 30-07-15, 23:10, Stephen Boyd wrote:
> On 07/29, Viresh Kumar wrote:
> > +bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp)
> > +{
> > + struct dev_pm_opp *tmp_opp;
> > +
> > + opp_rcu_lockdep_assert();
> > +
> > + tmp_opp = rcu_dereference(opp);
> > + if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available) {
>
> IS_ERR_OR_NULL already has unlikely inside it on the error
> pointer path so it seems redundant here.
>
> Otherwise
>
> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>

----------------------8<----------------------
Message-Id: <f925cccfbe4765bc6b15740a43e5688d2a283fb0.1438323394.git.viresh.kumar@linaro.org>
From: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Date: Thu, 9 Jul 2015 17:43:35 +0200
Subject: [PATCH] PM / OPP: add dev_pm_opp_is_turbo() helper

Add dev_pm_opp_is_turbo() helper to verify if an opp is to be used only
for turbo mode or not.

Cc: Tomasz Figa <tomasz.figa@gmail.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Javier Martinez Canillas <javier@dowhile0.org>
Cc: Thomas Abraham <thomas.ab@samsung.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/base/power/opp.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/pm_opp.h | 7 +++++++
2 files changed, 41 insertions(+)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 663aae1c9834..204c6c945168 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -281,6 +281,40 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);

/**
+ * dev_pm_opp_is_turbo() - Returns if opp is turbo OPP or not
+ * @opp: opp for which turbo mode is being verified
+ *
+ * Turbo OPPs are not for normal use, and can be enabled (under certain
+ * conditions) for short duration of times to finish high throughput work
+ * quickly. Running on them for longer times may overheat the chip.
+ *
+ * Return: true if opp is turbo opp, else false.
+ *
+ * Locking: This function must be called under rcu_read_lock(). opp is a rcu
+ * protected pointer. This means that opp which could have been fetched by
+ * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
+ * under RCU lock. The pointer returned by the opp_find_freq family must be
+ * used in the same section as the usage of this function with the pointer
+ * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
+ * pointer.
+ */
+bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp)
+{
+ struct dev_pm_opp *tmp_opp;
+
+ opp_rcu_lockdep_assert();
+
+ tmp_opp = rcu_dereference(opp);
+ if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) {
+ pr_err("%s: Invalid parameters\n", __func__);
+ return false;
+ }
+
+ return tmp_opp->turbo;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo);
+
+/**
* dev_pm_opp_get_max_clock_latency() - Get max clock latency in nanoseconds
* @dev: device for which we do this operation
*
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index bb52fae5b921..cab7ba55bedb 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -30,6 +30,8 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp);

unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp);

+bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp);
+
int dev_pm_opp_get_opp_count(struct device *dev);
unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev);

@@ -63,6 +65,11 @@ static inline unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
return 0;
}

+static inline bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp)
+{
+ return false;
+}
+
static inline int dev_pm_opp_get_opp_count(struct device *dev)
{
return 0;