} while (0)
/**
- * find_device_opp() - find device_opp struct using device pointer
+ * _find_device_opp() - find device_opp struct using device pointer
* @dev: device pointer used to lookup device OPPs
*
* Search list of device OPPs for one containing matching device. Does a RCU
* reader operation to grab the pointer needed.
*
- * Returns pointer to 'struct device_opp' if found, otherwise -ENODEV or
+ * Return: pointer to 'struct device_opp' if found, otherwise -ENODEV or
* -EINVAL based on type of error.
*
* Locking: This function must be called under rcu_read_lock(). device_opp
* is a RCU protected pointer. This means that device_opp is valid as long
* as we are under RCU lock.
*/
-static struct device_opp *find_device_opp(struct device *dev)
+static struct device_opp *_find_device_opp(struct device *dev)
{
struct device_opp *tmp_dev_opp, *dev_opp = ERR_PTR(-ENODEV);
* dev_pm_opp_get_voltage() - Gets the voltage corresponding to an available opp
* @opp: opp for which voltage has to be returned for
*
- * Return voltage in micro volt corresponding to the opp, else
+ * Return: voltage in micro volt corresponding to the opp, else
* return 0
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
struct dev_pm_opp *tmp_opp;
unsigned long v = 0;
+ opp_rcu_lockdep_assert();
+
tmp_opp = rcu_dereference(opp);
if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available)
pr_err("%s: Invalid parameters\n", __func__);
* dev_pm_opp_get_freq() - Gets the frequency corresponding to an available opp
* @opp: opp for which frequency has to be returned for
*
- * Return frequency in hertz corresponding to the opp, else
+ * Return: frequency in hertz corresponding to the opp, else
* return 0
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
struct dev_pm_opp *tmp_opp;
unsigned long f = 0;
+ opp_rcu_lockdep_assert();
+
tmp_opp = rcu_dereference(opp);
if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available)
pr_err("%s: Invalid parameters\n", __func__);
* dev_pm_opp_get_opp_count() - Get number of opps available in the opp list
* @dev: device for which we do this operation
*
- * This function returns the number of available opps if there are any,
+ * Return: This function returns the number of available opps if there are any,
* else returns 0 if none or the corresponding error value.
*
* Locking: This function takes rcu_read_lock().
rcu_read_lock();
- dev_opp = find_device_opp(dev);
+ dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp)) {
count = PTR_ERR(dev_opp);
dev_err(dev, "%s: device OPP not found (%d)\n",
* @freq: frequency to search for
* @available: true/false - match for available opp
*
- * Searches for exact match in the opp list and returns pointer to the matching
- * opp if found, else returns ERR_PTR in case of error and should be handled
- * using IS_ERR. Error return values can be:
+ * Return: Searches for exact match in the opp list and returns pointer to the
+ * matching opp if found, else returns ERR_PTR in case of error and should
+ * be handled using IS_ERR. Error return values can be:
* EINVAL: for bad pointer
* ERANGE: no match found for search
* ENODEV: if device not found in list of registered devices
opp_rcu_lockdep_assert();
- dev_opp = find_device_opp(dev);
+ dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp)) {
int r = PTR_ERR(dev_opp);
dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r);
* Search for the matching ceil *available* OPP from a starting freq
* for a device.
*
- * Returns matching *opp and refreshes *freq accordingly, else returns
+ * Return: matching *opp and refreshes *freq accordingly, else returns
* ERR_PTR in case of error and should be handled using IS_ERR. Error return
* values can be:
* EINVAL: for bad pointer
return ERR_PTR(-EINVAL);
}
- dev_opp = find_device_opp(dev);
+ dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp))
return ERR_CAST(dev_opp);
* Search for the matching floor *available* OPP from a starting freq
* for a device.
*
- * Returns matching *opp and refreshes *freq accordingly, else returns
+ * Return: matching *opp and refreshes *freq accordingly, else returns
* ERR_PTR in case of error and should be handled using IS_ERR. Error return
* values can be:
* EINVAL: for bad pointer
return ERR_PTR(-EINVAL);
}
- dev_opp = find_device_opp(dev);
+ dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp))
return ERR_CAST(dev_opp);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
-static struct device_opp *add_device_opp(struct device *dev)
+/**
+ * _add_device_opp() - Allocate a new device OPP table
+ * @dev: device for which we do this operation
+ *
+ * New device node which uses OPPs - used when multiple devices with OPP tables
+ * are maintained.
+ *
+ * Return: valid device_opp pointer if success, else NULL.
+ */
+static struct device_opp *_add_device_opp(struct device *dev)
{
struct device_opp *dev_opp;
return dev_opp;
}
-static int dev_pm_opp_add_dynamic(struct device *dev, unsigned long freq,
- unsigned long u_volt, bool dynamic)
+/**
+ * _opp_add_dynamic() - Allocate a dynamic OPP.
+ * @dev: device for which we do this operation
+ * @freq: Frequency in Hz for this OPP
+ * @u_volt: Voltage in uVolts for this OPP
+ * @dynamic: Dynamically added OPPs.
+ *
+ * This function adds an opp definition to the opp list and returns status.
+ * The opp is made available by default and it can be controlled using
+ * dev_pm_opp_enable/disable functions and may be removed by dev_pm_opp_remove.
+ *
+ * NOTE: "dynamic" parameter impacts OPPs added by the of_init_opp_table and
+ * freed by of_free_opp_table.
+ *
+ * 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 cannot be locked.
+ *
+ * Return:
+ * 0 On success OR
+ * Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST Freq are same and volt are different OR
+ * Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM Memory allocation failure
+ */
+static int _opp_add_dynamic(struct device *dev, unsigned long freq,
+ long u_volt, bool dynamic)
{
struct device_opp *dev_opp = NULL;
struct dev_pm_opp *opp, *new_opp;
/* allocate new OPP node */
new_opp = kzalloc(sizeof(*new_opp), GFP_KERNEL);
- if (!new_opp) {
- dev_warn(dev, "%s: Unable to create new OPP node\n", __func__);
+ if (!new_opp)
return -ENOMEM;
- }
/* Hold our list modification lock here */
mutex_lock(&dev_opp_list_lock);
new_opp->dynamic = dynamic;
/* Check for existing list for 'dev' */
- dev_opp = find_device_opp(dev);
+ dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp)) {
- dev_opp = add_device_opp(dev);
+ dev_opp = _add_device_opp(dev);
if (!dev_opp) {
ret = -ENOMEM;
goto free_opp;
* mutex cannot be locked.
*
* Return:
- * 0: On success OR
+ * 0 On success OR
* Duplicate OPPs (both freq and volt are same) and opp->available
- * -EEXIST: Freq are same and volt are different OR
+ * -EEXIST Freq are same and volt are different OR
* Duplicate OPPs (both freq and volt are same) and !opp->available
- * -ENOMEM: Memory allocation failure
+ * -ENOMEM Memory allocation failure
*/
int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
{
- return dev_pm_opp_add_dynamic(dev, freq, u_volt, true);
+ return _opp_add_dynamic(dev, freq, u_volt, true);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_add);
-static void kfree_opp_rcu(struct rcu_head *head)
+/**
+ * _kfree_opp_rcu() - Free OPP RCU handler
+ * @head: RCU head
+ */
+static void _kfree_opp_rcu(struct rcu_head *head)
{
struct dev_pm_opp *opp = container_of(head, struct dev_pm_opp, rcu_head);
kfree_rcu(opp, rcu_head);
}
-static void kfree_device_rcu(struct rcu_head *head)
+/**
+ * _kfree_device_rcu() - Free device_opp RCU handler
+ * @head: RCU head
+ */
+static void _kfree_device_rcu(struct rcu_head *head)
{
struct device_opp *device_opp = container_of(head, struct device_opp, rcu_head);
kfree_rcu(device_opp, rcu_head);
}
-static void __dev_pm_opp_remove(struct device_opp *dev_opp,
- struct dev_pm_opp *opp)
+/**
+ * _opp_remove() - Remove an OPP from a table definition
+ * @dev_opp: points back to the device_opp struct this opp belongs to
+ * @opp: pointer to the OPP to remove
+ *
+ * This function removes an opp definition from the opp list.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * It is assumed that the caller holds required mutex for an RCU updater
+ * strategy.
+ */
+static void _opp_remove(struct device_opp *dev_opp,
+ struct dev_pm_opp *opp)
{
/*
* Notify the changes in the availability of the operable
*/
srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_REMOVE, opp);
list_del_rcu(&opp->node);
- call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, kfree_opp_rcu);
+ call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
if (list_empty(&dev_opp->opp_list)) {
list_del_rcu(&dev_opp->node);
call_srcu(&dev_opp->srcu_head.srcu, &dev_opp->rcu_head,
- kfree_device_rcu);
+ _kfree_device_rcu);
}
}
* @freq: OPP to remove with matching 'freq'
*
* This function removes an opp from the opp list.
+ *
+ * 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 cannot be locked.
*/
void dev_pm_opp_remove(struct device *dev, unsigned long freq)
{
/* Hold our list modification lock here */
mutex_lock(&dev_opp_list_lock);
- dev_opp = find_device_opp(dev);
+ dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp))
goto unlock;
goto unlock;
}
- __dev_pm_opp_remove(dev_opp, opp);
+ _opp_remove(dev_opp, opp);
unlock:
mutex_unlock(&dev_opp_list_lock);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
/**
- * opp_set_availability() - helper to set the availability of an opp
+ * _opp_set_availability() - helper to set the availability of an opp
* @dev: device for which we do this operation
* @freq: OPP frequency to modify availability
* @availability_req: availability status requested for this opp
* Set the availability of an OPP with an RCU operation, opp_{enable,disable}
* share a common logic which is isolated here.
*
- * Returns -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * 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.
*
* that this function is *NOT* called under RCU protection or in contexts where
* mutex locking or synchronize_rcu() blocking calls cannot be used.
*/
-static int opp_set_availability(struct device *dev, unsigned long freq,
- bool availability_req)
+static int _opp_set_availability(struct device *dev, unsigned long freq,
+ bool availability_req)
{
struct device_opp *dev_opp;
struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV);
/* keep the node allocated */
new_opp = kmalloc(sizeof(*new_opp), GFP_KERNEL);
- if (!new_opp) {
- dev_warn(dev, "%s: Unable to create OPP\n", __func__);
+ if (!new_opp)
return -ENOMEM;
- }
mutex_lock(&dev_opp_list_lock);
/* Find the device_opp */
- dev_opp = find_device_opp(dev);
+ 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);
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);
+ call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
/* Notify the change of the OPP availability */
if (availability_req)
* 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.
+ *
+ * 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.
*/
int dev_pm_opp_enable(struct device *dev, unsigned long freq)
{
- return opp_set_availability(dev, freq, true);
+ return _opp_set_availability(dev, freq, true);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_enable);
* 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.
+ *
+ * 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.
*/
int dev_pm_opp_disable(struct device *dev, unsigned long freq)
{
- return opp_set_availability(dev, freq, false);
+ return _opp_set_availability(dev, freq, false);
}
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 device OPPs.
+ *
+ * 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(). dev_opp 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.
*/
struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
{
- struct device_opp *dev_opp = find_device_opp(dev);
+ struct device_opp *dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp))
return ERR_CAST(dev_opp); /* matching type */
return &dev_opp->srcu_head;
}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier);
#ifdef CONFIG_OF
/**
* @dev: device pointer used to lookup device OPPs.
*
* Register the initial OPP table with the OPP library for given device.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly 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 cannot be locked.
+ *
+ * Return:
+ * 0 On success OR
+ * Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST Freq are same and volt are different OR
+ * Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM Memory allocation failure
+ * -ENODEV when 'operating-points' property is not found or is invalid data
+ * in device node.
+ * -ENODATA when empty 'operating-points' property is found
*/
int of_init_opp_table(struct device *dev)
{
unsigned long freq = be32_to_cpup(val++) * 1000;
unsigned long volt = be32_to_cpup(val++);
- if (dev_pm_opp_add_dynamic(dev, freq, volt, false))
+ if (_opp_add_dynamic(dev, freq, volt, false))
dev_warn(dev, "%s: Failed to add OPP %ld\n",
__func__, freq);
nr -= 2;
* @dev: device pointer used to lookup device OPPs.
*
* Free OPPs created using static entries present in DT.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly 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 cannot be locked.
*/
void of_free_opp_table(struct device *dev)
{
struct dev_pm_opp *opp, *tmp;
/* Check for existing list for 'dev' */
- dev_opp = find_device_opp(dev);
+ dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp)) {
int error = PTR_ERR(dev_opp);
if (error != -ENODEV)
/* Free static OPPs */
list_for_each_entry_safe(opp, tmp, &dev_opp->opp_list, node) {
if (!opp->dynamic)
- __dev_pm_opp_remove(dev_opp, opp);
+ _opp_remove(dev_opp, opp);
}
mutex_unlock(&dev_opp_list_lock);
projects / linux-drm-fsl-dcu.git / blobdiff