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PM / OPP: Don't expose srcu_head to register notifiers

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Let the OPP core provide helpers to register notifiers for any device,
instead of exposing srcu_head outside of the core.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar
2017-01-02 14:41:03 +05:30
committed by Rafael J. Wysocki
parent 3aa26a3b2e
commit dc2c9ad52a
3 changed files with 63 additions and 45 deletions
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68
drivers/base/power/opp/core.c
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@@ -1860,29 +1860,63 @@ int dev_pm_opp_disable(struct device *dev, unsigned long freq)
EXPORT_SYMBOL_GPL(dev_pm_opp_disable);
/**
* dev_pm_opp_get_notifier() - find notifier_head of the device with opp
* @dev: device pointer used to lookup OPP table.
* dev_pm_opp_register_notifier() - Register OPP notifier for the device
* @dev: Device for which notifier needs to be registered
* @nb: Notifier block to be registered
*
* Return: pointer to notifier head if found, otherwise -ENODEV or
* -EINVAL based on type of error casted as pointer. value must be checked
* with IS_ERR to determine valid pointer or error result.
*
* Locking: This function must be called under rcu_read_lock(). opp_table is a
* RCU protected pointer. The reason for the same is that the opp pointer which
* is returned will remain valid for use with opp_get_{voltage, freq} only while
* under the locked area. The pointer returned must be used prior to unlocking
* with rcu_read_unlock() to maintain the integrity of the pointer.
* Return: 0 on success or a negative error value.
*/
struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
int dev_pm_opp_register_notifier(struct device *dev, struct notifier_block *nb)
{
struct opp_table *opp_table = _find_opp_table(dev);
struct opp_table *opp_table;
int ret;
if (IS_ERR(opp_table))
return ERR_CAST(opp_table); /* matching type */
rcu_read_lock();
return &opp_table->srcu_head;
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table)) {
ret = PTR_ERR(opp_table);
goto unlock;
}
ret = srcu_notifier_chain_register(&opp_table->srcu_head, nb);
unlock:
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier);
EXPORT_SYMBOL(dev_pm_opp_register_notifier);
/**
* dev_pm_opp_unregister_notifier() - Unregister OPP notifier for the device
* @dev: Device for which notifier needs to be unregistered
* @nb: Notifier block to be unregistered
*
* Return: 0 on success or a negative error value.
*/
int dev_pm_opp_unregister_notifier(struct device *dev,
struct notifier_block *nb)
{
struct opp_table *opp_table;
int ret;
rcu_read_lock();
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table)) {
ret = PTR_ERR(opp_table);
goto unlock;
}
ret = srcu_notifier_chain_unregister(&opp_table->srcu_head, nb);
unlock:
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL(dev_pm_opp_unregister_notifier);
/*
* Free OPPs either created using static entries present in DT or even the