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Date: Wed, 29 Jul 2015 16:23:03 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Rafael Wysocki <rjw@...ysocki.net>, sboyd@...eaurora.org
Cc: linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
rob.herring@...aro.org, arnd.bergmann@...aro.org, nm@...com,
broonie@...nel.org, mturquette@...libre.com, Sudeep.Holla@....com,
viswanath.puttagunta@...aro.org, l.stach@...gutronix.de,
thomas.petazzoni@...e-electrons.com,
linux-arm-kernel@...ts.infradead.org, ta.omasab@...il.com,
kesavan.abhilash@...il.com, khilman@...aro.org,
santosh.shilimkar@...cle.com, b.zolnierkie@...sung.com,
Viresh Kumar <viresh.kumar@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Len Brown <len.brown@...el.com>,
linux-kernel@...r.kernel.org (open list),
Pavel Machek <pavel@....cz>
Subject: [PATCH V3 08/16] PM / OPP: Add clock-latency-ns support
With "operating-points-v2" bindings, clock-latency is defined per OPP.
Users of this value expect a single value which defines the latency to
switch to any clock rate. Find maximum clock-latency-ns from the OPP
table to service requests from such users.
Reviewed-by: Stephen Boyd <sboyd@...eaurora.org>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
drivers/base/power/opp.c | 41 +++++++++++++++++++++++++++++++++++++++--
include/linux/pm_opp.h | 6 ++++++
2 files changed, 45 insertions(+), 2 deletions(-)
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 0e0eff4d9299..8638204c457e 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -57,6 +57,8 @@
* @u_volt_min: Minimum voltage in microvolts corresponding to this OPP
* @u_volt_max: Maximum voltage in microvolts corresponding to this OPP
* @u_amp: Maximum current drawn by the device in microamperes
+ * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
+ * frequency from any other OPP's frequency.
* @dev_opp: points back to the device_opp struct this opp belongs to
* @rcu_head: RCU callback head used for deferred freeing
* @np: OPP's device node.
@@ -75,6 +77,7 @@ struct dev_pm_opp {
unsigned long u_volt_min;
unsigned long u_volt_max;
unsigned long u_amp;
+ unsigned long clock_latency_ns;
struct device_opp *dev_opp;
struct rcu_head rcu_head;
@@ -109,6 +112,8 @@ struct device_opp {
struct srcu_notifier_head srcu_head;
struct rcu_head rcu_head;
struct list_head opp_list;
+
+ unsigned long clock_latency_ns_max;
};
/*
@@ -226,6 +231,32 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
/**
+ * dev_pm_opp_get_max_clock_latency() - Get max clock latency in nanoseconds
+ * @dev: device for which we do this operation
+ *
+ * Return: This function returns the max clock latency in nanoseconds.
+ *
+ * Locking: This function takes rcu_read_lock().
+ */
+unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)
+{
+ struct device_opp *dev_opp;
+ unsigned long clock_latency_ns;
+
+ rcu_read_lock();
+
+ dev_opp = _find_device_opp(dev);
+ if (IS_ERR(dev_opp))
+ clock_latency_ns = 0;
+ else
+ clock_latency_ns = dev_opp->clock_latency_ns_max;
+
+ rcu_read_unlock();
+ return clock_latency_ns;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);
+
+/**
* dev_pm_opp_get_opp_count() - Get number of opps available in the opp list
* @dev: device for which we do this operation
*
@@ -779,6 +810,8 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np)
new_opp->np = np;
new_opp->dynamic = false;
new_opp->available = true;
+ of_property_read_u32(np, "clock-latency-ns",
+ (u32 *)&new_opp->clock_latency_ns);
ret = opp_get_microvolt(new_opp, dev);
if (ret)
@@ -790,11 +823,15 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np)
if (ret)
goto free_opp;
+ if (new_opp->clock_latency_ns > dev_opp->clock_latency_ns_max)
+ dev_opp->clock_latency_ns_max = new_opp->clock_latency_ns;
+
mutex_unlock(&dev_opp_list_lock);
- pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu\n",
+ pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n",
__func__, new_opp->turbo, new_opp->rate, new_opp->u_volt,
- new_opp->u_volt_min, new_opp->u_volt_max);
+ new_opp->u_volt_min, new_opp->u_volt_max,
+ new_opp->clock_latency_ns);
/*
* Notify the changes in the availability of the operable
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index cec2d4540914..20324b579adc 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -31,6 +31,7 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp);
unsigned long dev_pm_opp_get_freq(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);
struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
unsigned long freq,
@@ -67,6 +68,11 @@ static inline int dev_pm_opp_get_opp_count(struct device *dev)
return 0;
}
+static inline unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)
+{
+ return 0;
+}
+
static inline struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
unsigned long freq, bool available)
{
--
2.4.0
--
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