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>
This commit is contained in:
Pavel Kubelun
John Crispin
parent
8749fb7894
commit
a154a3d8be
2 changed files with 259 additions and 0 deletions
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From 111139c943a082364fbbcd9e0cc94cd442481340 Mon Sep 17 00:00:00 2001
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From: Stephen Boyd <sboyd@codeaurora.org>
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Date: Mon, 1 Jun 2015 18:47:56 -0700
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Subject: PM / OPP: Support adjusting OPP voltages at runtime
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On some SoCs the Adaptive Voltage Scaling (AVS) technique is
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employed to optimize the operating voltage of a device. At a
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given frequency, the hardware monitors dynamic factors and either
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makes a suggestion for how much to adjust a voltage for the
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current frequency, or it automatically adjusts the voltage
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without software intervention. Add an API to the OPP library for
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the former case, so that AVS type devices can update the voltages
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for an OPP when the hardware determines the voltage should
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change. The assumption is that drivers like CPUfreq or devfreq
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will register for the OPP notifiers and adjust the voltage
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according to suggestions that AVS makes.
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Cc: Nishanth Menon <nm@ti.com>
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Cc: Viresh Kumar <viresh.kumar@linaro.org>
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Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
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Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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---
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drivers/base/power/opp/core.c | 77 +++++++++++++++++++++++++++++++++++++++++++
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include/linux/pm_opp.h | 10 ++++++
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2 files changed, 87 insertions(+)
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--- a/drivers/base/power/opp/core.c
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+++ b/drivers/base/power/opp/core.c
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@@ -1039,6 +1039,83 @@ unlock:
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}
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/**
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+ * dev_pm_opp_adjust_voltage() - helper to change the voltage of an opp
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+ * @dev: device for which we do this operation
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+ * @freq: OPP frequency to adjust voltage of
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+ * @u_volt: new OPP voltage
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+ *
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+ * Change the voltage of an OPP with an RCU operation.
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+ *
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+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
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+ * copy operation, returns 0 if no modifcation was done OR modification was
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+ * successful.
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+ *
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+ * Locking: The internal device_opp and opp structures are RCU protected.
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+ * Hence this function internally uses RCU updater strategy with mutex locks to
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+ * keep the integrity of the internal data structures. Callers should ensure
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+ * that this function is *NOT* called under RCU protection or in contexts where
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+ * mutex locking or synchronize_rcu() blocking calls cannot be used.
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+ */
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+int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
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+ unsigned long u_volt)
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+{
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+ struct device_opp *dev_opp;
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+ struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV);
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+ int r = 0;
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+
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+ /* keep the node allocated */
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+ new_opp = kmalloc(sizeof(*new_opp), GFP_KERNEL);
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+ if (!new_opp)
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+ return -ENOMEM;
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+
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+ mutex_lock(&dev_opp_list_lock);
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+
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+ /* Find the device_opp */
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+ dev_opp = _find_device_opp(dev);
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+ if (IS_ERR(dev_opp)) {
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+ r = PTR_ERR(dev_opp);
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+ dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
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+ goto unlock;
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+ }
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+
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+ /* Do we have the frequency? */
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+ list_for_each_entry(tmp_opp, &dev_opp->opp_list, node) {
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+ if (tmp_opp->rate == freq) {
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+ opp = tmp_opp;
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+ break;
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+ }
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+ }
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+ if (IS_ERR(opp)) {
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+ r = PTR_ERR(opp);
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+ goto unlock;
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+ }
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+
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+ /* Is update really needed? */
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+ if (opp->u_volt == u_volt)
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+ goto unlock;
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+ /* copy the old data over */
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+ *new_opp = *opp;
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+
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+ /* plug in new node */
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+ new_opp->u_volt = u_volt;
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+
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+ list_replace_rcu(&opp->node, &new_opp->node);
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+ mutex_unlock(&dev_opp_list_lock);
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+ call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
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+
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+ /* Notify the change of the OPP */
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+ srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADJUST_VOLTAGE,
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+ new_opp);
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+
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+ return 0;
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+
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+unlock:
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+ mutex_unlock(&dev_opp_list_lock);
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+ kfree(new_opp);
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+ return r;
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+}
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+
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+/**
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* dev_pm_opp_enable() - Enable a specific OPP
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* @dev: device for which we do this operation
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* @freq: OPP frequency to enable
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--- a/include/linux/pm_opp.h
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+++ b/include/linux/pm_opp.h
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@@ -22,6 +22,7 @@ struct device;
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enum dev_pm_opp_event {
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OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE,
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+ OPP_EVENT_ADJUST_VOLTAGE,
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};
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#if defined(CONFIG_PM_OPP)
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@@ -50,6 +51,9 @@ int dev_pm_opp_add(struct device *dev, u
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unsigned long u_volt);
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void dev_pm_opp_remove(struct device *dev, unsigned long freq);
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+int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
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+ unsigned long u_volt);
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+
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int dev_pm_opp_enable(struct device *dev, unsigned long freq);
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int dev_pm_opp_disable(struct device *dev, unsigned long freq);
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@@ -114,6 +118,12 @@ static inline void dev_pm_opp_remove(str
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{
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}
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+static inline int dev_pm_opp_adjust_voltage(struct device *dev,
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+ unsigned long freq, unsigned long u_volt)
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+{
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+ return 0;
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+}
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+
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static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq)
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{
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return 0;
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@ -0,0 +1,114 @@
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From d330eae026b4a73e77ca0422f5cae5207d80f738 Mon Sep 17 00:00:00 2001
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From: Stephen Boyd <sboyd@codeaurora.org>
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Date: Mon, 1 Jun 2015 18:47:57 -0700
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Subject: OPP: Allow notifiers to call dev_pm_opp_get_{voltage, freq} RCU-free
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We pass the dev_pm_opp structure to OPP notifiers but the users
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of the notifier need to surround calls to dev_pm_opp_get_*() with
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RCU read locks to avoid lockdep warnings. The notifier is already
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called with the dev_opp's srcu lock held, so it should be safe to
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assume the devm_pm_opp structure is already protected inside the
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notifier. Update the lockdep check for this.
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Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
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Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
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---
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drivers/base/power/opp/core.c | 27 +++++++++++++++------------
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1 file changed, 15 insertions(+), 12 deletions(-)
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--- a/drivers/base/power/opp/core.c
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+++ b/drivers/base/power/opp/core.c
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@@ -31,9 +31,10 @@ static LIST_HEAD(dev_opp_list);
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/* Lock to allow exclusive modification to the device and opp lists */
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DEFINE_MUTEX(dev_opp_list_lock);
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-#define opp_rcu_lockdep_assert() \
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+#define opp_rcu_lockdep_assert(s) \
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do { \
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RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
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+ !(s && srcu_read_lock_held(s)) && \
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!lockdep_is_held(&dev_opp_list_lock), \
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"Missing rcu_read_lock() or " \
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"dev_opp_list_lock protection"); \
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@@ -91,7 +92,7 @@ struct device_opp *_find_device_opp(stru
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{
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struct device_opp *dev_opp;
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- opp_rcu_lockdep_assert();
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+ opp_rcu_lockdep_assert(NULL);
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if (IS_ERR_OR_NULL(dev)) {
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pr_err("%s: Invalid parameters\n", __func__);
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@@ -125,10 +126,11 @@ unsigned long dev_pm_opp_get_voltage(str
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struct dev_pm_opp *tmp_opp;
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unsigned long v = 0;
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- opp_rcu_lockdep_assert();
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+ opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu);
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- tmp_opp = rcu_dereference(opp);
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- if (IS_ERR_OR_NULL(tmp_opp))
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+ tmp_opp = srcu_dereference_check(opp, &opp->dev_opp->srcu_head.srcu,
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+ rcu_read_lock_held());
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+ if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
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pr_err("%s: Invalid parameters\n", __func__);
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else
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v = tmp_opp->u_volt;
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@@ -157,9 +159,10 @@ unsigned long dev_pm_opp_get_freq(struct
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struct dev_pm_opp *tmp_opp;
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unsigned long f = 0;
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- opp_rcu_lockdep_assert();
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+ opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu);
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- tmp_opp = rcu_dereference(opp);
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+ tmp_opp = srcu_dereference_check(opp, &opp->dev_opp->srcu_head.srcu,
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+ rcu_read_lock_held());
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if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
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pr_err("%s: Invalid parameters\n", __func__);
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else
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@@ -191,7 +194,7 @@ bool dev_pm_opp_is_turbo(struct dev_pm_o
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{
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struct dev_pm_opp *tmp_opp;
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- opp_rcu_lockdep_assert();
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+ opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu);
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tmp_opp = rcu_dereference(opp);
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if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) {
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@@ -246,7 +249,7 @@ struct dev_pm_opp *dev_pm_opp_get_suspen
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{
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struct device_opp *dev_opp;
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- opp_rcu_lockdep_assert();
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+ opp_rcu_lockdep_assert(NULL);
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dev_opp = _find_device_opp(dev);
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if (IS_ERR(dev_opp) || !dev_opp->suspend_opp ||
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@@ -326,7 +329,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_
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struct device_opp *dev_opp;
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struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
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- opp_rcu_lockdep_assert();
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+ opp_rcu_lockdep_assert(NULL);
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dev_opp = _find_device_opp(dev);
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if (IS_ERR(dev_opp)) {
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@@ -374,7 +377,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_
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struct device_opp *dev_opp;
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struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
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- opp_rcu_lockdep_assert();
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+ opp_rcu_lockdep_assert(NULL);
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if (!dev || !freq) {
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dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
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@@ -424,7 +427,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_
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struct device_opp *dev_opp;
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struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
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- opp_rcu_lockdep_assert();
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+ opp_rcu_lockdep_assert(NULL);
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if (!dev || !freq) {
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dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
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