/branches/gl-inet/target/linux/ipq806x/patches-4.14/0049-PM-OPP-Support-adjusting-OPP-voltages-at-runtime.patch |
@@ -0,0 +1,147 @@ |
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 |
@@ -1605,6 +1605,83 @@ 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; |