diff options
Diffstat (limited to 'drivers/base/power/opp.c')
| -rw-r--r-- | drivers/base/power/opp.c | 102 |
1 files changed, 91 insertions, 11 deletions
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c index 7ae7cd990fbf..c25624e829b0 100644 --- a/drivers/base/power/opp.c +++ b/drivers/base/power/opp.c @@ -146,10 +146,11 @@ static LIST_HEAD(dev_opp_list); /* Lock to allow exclusive modification to the device and opp lists */ static 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() && \ - !lockdep_is_held(&dev_opp_list_lock), \ + !((s && srcu_read_lock_held(s)) || \ + lockdep_is_held(&dev_opp_list_lock)), \ "Missing rcu_read_lock() or " \ "dev_opp_list_lock protection"); \ } while (0) @@ -236,9 +237,10 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp) 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); + 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 @@ -268,9 +270,10 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp) 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 @@ -302,7 +305,7 @@ bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp) { 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) { @@ -357,7 +360,7 @@ struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev) { 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 || @@ -437,7 +440,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, 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)) { @@ -485,7 +488,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev, 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); @@ -535,7 +538,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev, 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); @@ -1143,6 +1146,83 @@ 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 |