PM / OPP: Update kernel documentation
kernel doc has gotten bit-rotted over time. Re-sync with Locking and Return information. document all functions properly and ensure that ./scripts/kernel-doc -v ./drivers/base/power/opp.c >/dev/null returns no errors Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>hifive-unleashed-5.1
Nishanth Menon
Rafael J. Wysocki
parent
327854c871
commit
984f16c849
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@ -123,7 +123,7 @@ do { \
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* Search list of device OPPs for one containing matching device. Does a RCU
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* reader operation to grab the pointer needed.
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*
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* Returns pointer to 'struct device_opp' if found, otherwise -ENODEV or
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* Return: pointer to 'struct device_opp' if found, otherwise -ENODEV or
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* -EINVAL based on type of error.
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*
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* Locking: This function must be called under rcu_read_lock(). device_opp
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@ -153,7 +153,7 @@ static struct device_opp *_find_device_opp(struct device *dev)
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* dev_pm_opp_get_voltage() - Gets the voltage corresponding to an available opp
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* @opp: opp for which voltage has to be returned for
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*
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* Return voltage in micro volt corresponding to the opp, else
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* Return: voltage in micro volt corresponding to the opp, else
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* return 0
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*
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* Locking: This function must be called under rcu_read_lock(). opp is a rcu
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@ -183,7 +183,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
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* dev_pm_opp_get_freq() - Gets the frequency corresponding to an available opp
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* @opp: opp for which frequency has to be returned for
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*
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* Return frequency in hertz corresponding to the opp, else
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* Return: frequency in hertz corresponding to the opp, else
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* return 0
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*
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* Locking: This function must be called under rcu_read_lock(). opp is a rcu
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@ -213,7 +213,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
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* dev_pm_opp_get_opp_count() - Get number of opps available in the opp list
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* @dev: device for which we do this operation
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*
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* This function returns the number of available opps if there are any,
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* Return: This function returns the number of available opps if there are any,
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* else returns 0 if none or the corresponding error value.
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*
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* Locking: This function takes rcu_read_lock().
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@ -251,9 +251,9 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
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* @freq: frequency to search for
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* @available: true/false - match for available opp
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*
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* Searches for exact match in the opp list and returns pointer to the matching
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* opp if found, else returns ERR_PTR in case of error and should be handled
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* using IS_ERR. Error return values can be:
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* Return: Searches for exact match in the opp list and returns pointer to the
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* matching opp if found, else returns ERR_PTR in case of error and should
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* be handled using IS_ERR. Error return values can be:
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* EINVAL: for bad pointer
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* ERANGE: no match found for search
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* ENODEV: if device not found in list of registered devices
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@ -307,7 +307,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
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* Search for the matching ceil *available* OPP from a starting freq
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* for a device.
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*
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* Returns matching *opp and refreshes *freq accordingly, else returns
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* Return: matching *opp and refreshes *freq accordingly, else returns
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* ERR_PTR in case of error and should be handled using IS_ERR. Error return
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* values can be:
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* EINVAL: for bad pointer
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@ -357,7 +357,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
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* Search for the matching floor *available* OPP from a starting freq
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* for a device.
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*
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* Returns matching *opp and refreshes *freq accordingly, else returns
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* Return: matching *opp and refreshes *freq accordingly, else returns
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* ERR_PTR in case of error and should be handled using IS_ERR. Error return
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* values can be:
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* EINVAL: for bad pointer
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@ -403,6 +403,15 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
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}
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EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
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/**
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* _add_device_opp() - Allocate a new device OPP table
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* @dev: device for which we do this operation
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*
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* New device node which uses OPPs - used when multiple devices with OPP tables
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* are maintained.
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*
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* Return: valid device_opp pointer if success, else NULL.
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*/
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static struct device_opp *_add_device_opp(struct device *dev)
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{
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struct device_opp *dev_opp;
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@ -424,6 +433,33 @@ static struct device_opp *_add_device_opp(struct device *dev)
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return dev_opp;
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}
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/**
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* _opp_add_dynamic() - Allocate a dynamic OPP.
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* @dev: device for which we do this operation
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* @freq: Frequency in Hz for this OPP
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* @u_volt: Voltage in uVolts for this OPP
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* @dynamic: Dynamically added OPPs.
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*
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* This function adds an opp definition to the opp list and returns status.
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* The opp is made available by default and it can be controlled using
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* dev_pm_opp_enable/disable functions and may be removed by dev_pm_opp_remove.
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*
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* NOTE: "dynamic" parameter impacts OPPs added by the of_init_opp_table and
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* freed by of_free_opp_table.
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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
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* to 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 cannot be locked.
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*
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* Return:
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* 0 On success OR
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* Duplicate OPPs (both freq and volt are same) and opp->available
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* -EEXIST Freq are same and volt are different OR
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* Duplicate OPPs (both freq and volt are same) and !opp->available
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* -ENOMEM Memory allocation failure
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*/
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static int _opp_add_dynamic(struct device *dev, unsigned long freq,
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long u_volt, bool dynamic)
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{
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@ -519,11 +555,11 @@ free_opp:
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* mutex cannot be locked.
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*
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* Return:
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* 0: On success OR
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* 0 On success OR
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* Duplicate OPPs (both freq and volt are same) and opp->available
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* -EEXIST: Freq are same and volt are different OR
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* -EEXIST Freq are same and volt are different OR
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* Duplicate OPPs (both freq and volt are same) and !opp->available
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* -ENOMEM: Memory allocation failure
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* -ENOMEM Memory allocation failure
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*/
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int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
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{
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@ -531,6 +567,10 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
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}
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EXPORT_SYMBOL_GPL(dev_pm_opp_add);
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/**
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* _kfree_opp_rcu() - Free OPP RCU handler
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* @head: RCU head
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*/
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static void _kfree_opp_rcu(struct rcu_head *head)
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{
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struct dev_pm_opp *opp = container_of(head, struct dev_pm_opp, rcu_head);
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@ -538,6 +578,10 @@ static void _kfree_opp_rcu(struct rcu_head *head)
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kfree_rcu(opp, rcu_head);
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}
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/**
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* _kfree_device_rcu() - Free device_opp RCU handler
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* @head: RCU head
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*/
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static void _kfree_device_rcu(struct rcu_head *head)
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{
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struct device_opp *device_opp = container_of(head, struct device_opp, rcu_head);
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@ -545,6 +589,17 @@ static void _kfree_device_rcu(struct rcu_head *head)
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kfree_rcu(device_opp, rcu_head);
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}
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/**
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* _opp_remove() - Remove an OPP from a table definition
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* @dev_opp: points back to the device_opp struct this opp belongs to
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* @opp: pointer to the OPP to remove
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*
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* This function removes an opp definition from the opp list.
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*
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* Locking: The internal device_opp and opp structures are RCU protected.
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* It is assumed that the caller holds required mutex for an RCU updater
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* strategy.
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*/
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static void _opp_remove(struct device_opp *dev_opp,
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struct dev_pm_opp *opp)
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{
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@ -569,6 +624,12 @@ static void _opp_remove(struct device_opp *dev_opp,
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* @freq: OPP to remove with matching 'freq'
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*
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* This function removes an opp from the opp list.
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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
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* to 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 cannot be locked.
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*/
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void dev_pm_opp_remove(struct device *dev, unsigned long freq)
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{
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@ -611,7 +672,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
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* Set the availability of an OPP with an RCU operation, opp_{enable,disable}
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* share a common logic which is isolated here.
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*
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* Returns -EINVAL for bad pointers, -ENOMEM if no memory available for the
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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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@ -700,6 +761,10 @@ unlock:
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* integrity of the internal data structures. Callers should ensure that
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* 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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* 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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int dev_pm_opp_enable(struct device *dev, unsigned long freq)
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{
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@ -722,6 +787,10 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_enable);
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* integrity of the internal data structures. Callers should ensure that
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* 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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* 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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int dev_pm_opp_disable(struct device *dev, unsigned long freq)
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{
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@ -732,6 +801,16 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_disable);
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/**
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* dev_pm_opp_get_notifier() - find notifier_head of the device with opp
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* @dev: device pointer used to lookup device OPPs.
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*
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* Return: pointer to notifier head if found, otherwise -ENODEV or
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* -EINVAL based on type of error casted as pointer. value must be checked
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* with IS_ERR to determine valid pointer or error result.
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*
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* Locking: This function must be called under rcu_read_lock(). dev_opp is a RCU
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* protected pointer. The reason for the same is that the opp pointer which is
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* returned will remain valid for use with opp_get_{voltage, freq} only while
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* under the locked area. The pointer returned must be used prior to unlocking
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* with rcu_read_unlock() to maintain the integrity of the pointer.
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*/
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struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
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{
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@ -750,6 +829,22 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier);
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* @dev: device pointer used to lookup device OPPs.
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*
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* Register the initial OPP table with the OPP library for given device.
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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 indirectly uses RCU updater strategy with mutex locks
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* to 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 cannot be locked.
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*
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* Return:
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* 0 On success OR
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* Duplicate OPPs (both freq and volt are same) and opp->available
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* -EEXIST Freq are same and volt are different OR
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* Duplicate OPPs (both freq and volt are same) and !opp->available
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* -ENOMEM Memory allocation failure
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* -ENODEV when 'operating-points' property is not found or is invalid data
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* in device node.
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* -ENODATA when empty 'operating-points' property is found
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*/
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int of_init_opp_table(struct device *dev)
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{
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@ -793,6 +888,12 @@ EXPORT_SYMBOL_GPL(of_init_opp_table);
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* @dev: device pointer used to lookup device OPPs.
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*
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* Free OPPs created using static entries present in DT.
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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 indirectly uses RCU updater strategy with mutex locks
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* to 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 cannot be locked.
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*/
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void of_free_opp_table(struct device *dev)
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{
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