ipq806x: add opp patches for voltage scaling

Preparing for cpufreq driver switch to generic cpufreq-dt

Signed-off-by: Pavel Kubelun <be.dissent@gmail.com>

2 files changed, 259 insertions, 0 deletions

diff --git a/target/linux/ipq806x/patches-4.4/169-OPP-Support-adjusting-OPP-voltages-at-runtime.patch b/target/linux/ipq806x/patches-4.4/169-OPP-Support-adjusting-OPP-voltages-at-runtime.patch
new file mode 100644
index 0000000000..8f0afb504c
--- /dev/null
+++ b/target/linux/ipq806x/patches-4.4/169-OPP-Support-adjusting-OPP-voltages-at-runtime.patch
@@ -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;
diff --git a/target/linux/ipq806x/patches-4.4/170-OPP-Allow-notifiers-to-call-dev_pm_opp_get_voltage-freq-RCU-free.patch b/target/linux/ipq806x/patches-4.4/170-OPP-Allow-notifiers-to-call-dev_pm_opp_get_voltage-freq-RCU-free.patch
new file mode 100644
index 0000000000..7be47a3509
--- /dev/null
+++ b/target/linux/ipq806x/patches-4.4/170-OPP-Allow-notifiers-to-call-dev_pm_opp_get_voltage-freq-RCU-free.patch
@@ -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);