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ipq806x: add opp patches for voltage scaling

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Preparing for cpufreq driver switch to generic cpufreq-dt

Signed-off-by: Pavel Kubelun <be.dissent@gmail.com>
This commit is contained in:
Pavel Kubelun 2016-11-02 22:32:36 +03:00 committed by John Crispin
parent 8749fb7894
commit a154a3d8be
2 changed files with 259 additions and 0 deletions
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145
target/linux/ipq806x/patches-4.4/169-OPP-Support-adjusting-OPP-voltages-at-runtime.patch Normal file
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@ -0,0 +1,145 @@
From 111139c943a082364fbbcd9e0cc94cd442481340 Mon Sep 17 00:00:00 2001
From: Stephen Boyd <sboyd@codeaurora.org>
Date: Mon, 1 Jun 2015 18:47:56 -0700
Subject: 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>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/base/power/opp/core.c | 77 +++++++++++++++++++++++++++++++++++++++++++
include/linux/pm_opp.h | 10 ++++++
2 files changed, 87 insertions(+)
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -1039,6 +1039,83 @@ unlock:
}
/**
+ * 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 device_opp *dev_opp;
+ 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(&dev_opp_list_lock);
+
+ /* Find the device_opp */
+ dev_opp = _find_device_opp(dev);
+ if (IS_ERR(dev_opp)) {
+ r = PTR_ERR(dev_opp);
+ 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, &dev_opp->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->u_volt == u_volt)
+ goto unlock;
+ /* copy the old data over */
+ *new_opp = *opp;
+
+ /* plug in new node */
+ new_opp->u_volt = u_volt;
+
+ list_replace_rcu(&opp->node, &new_opp->node);
+ mutex_unlock(&dev_opp_list_lock);
+ call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
+
+ /* Notify the change of the OPP */
+ srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADJUST_VOLTAGE,
+ new_opp);
+
+ return 0;
+
+unlock:
+ mutex_unlock(&dev_opp_list_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
@@ -22,6 +22,7 @@ struct device;
enum dev_pm_opp_event {
OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE,
+ OPP_EVENT_ADJUST_VOLTAGE,
};
#if defined(CONFIG_PM_OPP)
@@ -50,6 +51,9 @@ 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);
@@ -114,6 +118,12 @@ 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;

114
target/linux/ipq806x/patches-4.4/170-OPP-Allow-notifiers-to-call-dev_pm_opp_get_voltage-freq-RCU-free.patch Normal file
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@ -0,0 +1,114 @@
From d330eae026b4a73e77ca0422f5cae5207d80f738 Mon Sep 17 00:00:00 2001
From: Stephen Boyd <sboyd@codeaurora.org>
Date: Mon, 1 Jun 2015 18:47:57 -0700
Subject: OPP: Allow notifiers to call dev_pm_opp_get_{voltage, freq} RCU-free
We pass the dev_pm_opp structure to OPP notifiers but the users
of the notifier need to surround calls to dev_pm_opp_get_*() with
RCU read locks to avoid lockdep warnings. The notifier is already
called with the dev_opp's srcu lock held, so it should be safe to
assume the devm_pm_opp structure is already protected inside the
notifier. Update the lockdep check for this.
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
drivers/base/power/opp/core.c | 27 +++++++++++++++------------
1 file changed, 15 insertions(+), 12 deletions(-)
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -31,9 +31,10 @@ static LIST_HEAD(dev_opp_list);
/* Lock to allow exclusive modification to the device and opp lists */
DEFINE_MUTEX(dev_opp_list_lock);
-#define opp_rcu_lockdep_assert() \
+#define opp_rcu_lockdep_assert(s) \
do { \
RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
+ !(s && srcu_read_lock_held(s)) && \
!lockdep_is_held(&dev_opp_list_lock), \
"Missing rcu_read_lock() or " \
"dev_opp_list_lock protection"); \
@@ -91,7 +92,7 @@ struct device_opp *_find_device_opp(stru
{
struct device_opp *dev_opp;
- opp_rcu_lockdep_assert();
+ opp_rcu_lockdep_assert(NULL);
if (IS_ERR_OR_NULL(dev)) {
pr_err("%s: Invalid parameters\n", __func__);
@@ -125,10 +126,11 @@ unsigned long dev_pm_opp_get_voltage(str
struct dev_pm_opp *tmp_opp;
unsigned long v = 0;
- opp_rcu_lockdep_assert();
+ opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu);
- tmp_opp = rcu_dereference(opp);
- if (IS_ERR_OR_NULL(tmp_opp))
+ tmp_opp = srcu_dereference_check(opp, &opp->dev_opp->srcu_head.srcu,
+ rcu_read_lock_held());
+ if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
pr_err("%s: Invalid parameters\n", __func__);
else
v = tmp_opp->u_volt;
@@ -157,9 +159,10 @@ unsigned long dev_pm_opp_get_freq(struct
struct dev_pm_opp *tmp_opp;
unsigned long f = 0;
- opp_rcu_lockdep_assert();
+ opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu);
- tmp_opp = rcu_dereference(opp);
+ tmp_opp = srcu_dereference_check(opp, &opp->dev_opp->srcu_head.srcu,
+ rcu_read_lock_held());
if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
pr_err("%s: Invalid parameters\n", __func__);
else
@@ -191,7 +194,7 @@ bool dev_pm_opp_is_turbo(struct dev_pm_o
{
struct dev_pm_opp *tmp_opp;
- opp_rcu_lockdep_assert();
+ opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu);
tmp_opp = rcu_dereference(opp);
if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) {
@@ -246,7 +249,7 @@ struct dev_pm_opp *dev_pm_opp_get_suspen
{
struct device_opp *dev_opp;
- opp_rcu_lockdep_assert();
+ opp_rcu_lockdep_assert(NULL);
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp) || !dev_opp->suspend_opp ||
@@ -326,7 +329,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_
struct device_opp *dev_opp;
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
- opp_rcu_lockdep_assert();
+ opp_rcu_lockdep_assert(NULL);
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp)) {
@@ -374,7 +377,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_
struct device_opp *dev_opp;
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
- opp_rcu_lockdep_assert();
+ opp_rcu_lockdep_assert(NULL);
if (!dev || !freq) {
dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
@@ -424,7 +427,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_
struct device_opp *dev_opp;
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
- opp_rcu_lockdep_assert();
+ opp_rcu_lockdep_assert(NULL);
if (!dev || !freq) {
dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);