--- /dev/null
+From c949f08cf20fe82971fbdb4015daa38210da492e Mon Sep 17 00:00:00 2001
+From: Stephen Boyd <sboyd@codeaurora.org>
+Date: Fri, 18 Sep 2015 17:52:06 -0700
+Subject: [PATCH 49/69] PM / OPP: Support adjusting OPP voltages at runtime
+
+On some SoCs the Adaptive Voltage Scaling (AVS) technique is
+employed to optimize the operating voltage of a device. At a
+given frequency, the hardware monitors dynamic factors and either
+makes a suggestion for how much to adjust a voltage for the
+current frequency, or it automatically adjusts the voltage
+without software intervention. Add an API to the OPP library for
+the former case, so that AVS type devices can update the voltages
+for an OPP when the hardware determines the voltage should
+change. The assumption is that drivers like CPUfreq or devfreq
+will register for the OPP notifiers and adjust the voltage
+according to suggestions that AVS makes.
+
+Cc: Nishanth Menon <nm@ti.com>
+Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
+Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
+Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
+Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
+---
+ drivers/base/power/opp/core.c | 77 +++++++++++++++++++++++++++++++++++++++++++
+ include/linux/pm_opp.h | 11 +++++++
+ 2 files changed, 88 insertions(+)
+
+--- a/drivers/base/power/opp/core.c
++++ b/drivers/base/power/opp/core.c
+@@ -1608,6 +1608,83 @@ put_table:
+ }
+
+ /**
++ * dev_pm_opp_adjust_voltage() - helper to change the voltage of an OPP
++ * @dev: device for which we do this operation
++ * @freq: OPP frequency to adjust voltage of
++ * @u_volt: new OPP voltage
++ *
++ * Change the voltage of an OPP with an RCU operation.
++ *
++ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
++ * copy operation, returns 0 if no modifcation was done OR modification was
++ * successful.
++ *
++ * Locking: The internal device_opp 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 locking or synchronize_rcu() blocking calls cannot be used.
++ */
++int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
++ unsigned long u_volt)
++{
++ struct opp_table *opp_table;
++ struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV);
++ int r = 0;
++
++ /* keep the node allocated */
++ new_opp = kmalloc(sizeof(*new_opp), GFP_KERNEL);
++ if (!new_opp)
++ return -ENOMEM;
++
++ mutex_lock(&opp_table_lock);
++
++ /* Find the opp_table */
++ opp_table = _find_opp_table(dev);
++ if (IS_ERR(opp_table)) {
++ r = PTR_ERR(opp_table);
++ dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
++ goto unlock;
++ }
++
++ /* Do we have the frequency? */
++ list_for_each_entry(tmp_opp, &opp_table->opp_list, node) {
++ if (tmp_opp->rate == freq) {
++ opp = tmp_opp;
++ break;
++ }
++ }
++ if (IS_ERR(opp)) {
++ r = PTR_ERR(opp);
++ goto unlock;
++ }
++
++ /* Is update really needed? */
++ if (opp->supplies[0].u_volt == u_volt)
++ goto unlock;
++ /* copy the old data over */
++ *new_opp = *opp;
++
++ /* plug in new node */
++ new_opp->supplies[0].u_volt = u_volt;
++
++ list_replace(&opp->node, &new_opp->node);
++ mutex_unlock(&opp_table_lock);
++ kfree(opp);
++
++ /* Notify the change of the OPP */
++ blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADJUST_VOLTAGE,
++ new_opp);
++
++ return 0;
++
++unlock:
++ mutex_unlock(&opp_table_lock);
++ kfree(new_opp);
++ return r;
++}
++
++/**
+ * dev_pm_opp_enable() - Enable a specific OPP
+ * @dev: device for which we do this operation
+ * @freq: OPP frequency to enable
+--- a/include/linux/pm_opp.h
++++ b/include/linux/pm_opp.h
+@@ -25,6 +25,7 @@ struct opp_table;
+
+ enum dev_pm_opp_event {
+ OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE,
++ OPP_EVENT_ADJUST_VOLTAGE,
+ };
+
+ /**
+@@ -108,6 +109,9 @@ int dev_pm_opp_add(struct device *dev, u
+ unsigned long u_volt);
+ void dev_pm_opp_remove(struct device *dev, unsigned long freq);
+
++int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
++ unsigned long u_volt);
++
+ int dev_pm_opp_enable(struct device *dev, unsigned long freq);
+
+ int dev_pm_opp_disable(struct device *dev, unsigned long freq);
+@@ -208,6 +212,13 @@ static inline void dev_pm_opp_remove(str
+ {
+ }
+
++static inline int
++dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
++ unsigned long u_volt)
++{
++ return 0;
++}
++
+ static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq)
+ {
+ return 0;
projects / openwrt / staging / ynezz.git / blobdiff