diff options
Diffstat (limited to 'drivers/base/power/opp/core.c')
| -rw-r--r-- | drivers/base/power/opp/core.c | 114 |
1 files changed, 63 insertions, 51 deletions
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c index 9870ee54d708..a6efa818029a 100644 --- a/drivers/base/power/opp/core.c +++ b/drivers/base/power/opp/core.c @@ -40,6 +40,8 @@ do { \ "opp_table_lock protection"); \ } while (0) +static void dev_pm_opp_get(struct dev_pm_opp *opp); + static struct opp_device *_find_opp_dev(const struct device *dev, struct opp_table *opp_table) { @@ -94,21 +96,13 @@ struct opp_table *_find_opp_table(struct device *dev) * return 0 * * This is useful only for devices with single power supply. - * - * Locking: This function must be called under rcu_read_lock(). opp is a rcu - * protected pointer. This means that opp which could have been fetched by - * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are - * under RCU lock. The pointer returned by the opp_find_freq family must be - * used in the same section as the usage of this function with the pointer - * prior to unlocking with rcu_read_unlock() to maintain the integrity of the - * pointer. */ 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(); + rcu_read_lock(); tmp_opp = rcu_dereference(opp); if (IS_ERR_OR_NULL(tmp_opp)) @@ -116,6 +110,7 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp) else v = tmp_opp->supplies[0].u_volt; + rcu_read_unlock(); return v; } EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage); @@ -126,21 +121,13 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage); * * 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 - * protected pointer. This means that opp which could have been fetched by - * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are - * under RCU lock. The pointer returned by the opp_find_freq family must be - * used in the same section as the usage of this function with the pointer - * prior to unlocking with rcu_read_unlock() to maintain the integrity of the - * pointer. */ 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(); + rcu_read_lock(); tmp_opp = rcu_dereference(opp); if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) @@ -148,6 +135,7 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp) else f = tmp_opp->rate; + rcu_read_unlock(); return f; } EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq); @@ -161,20 +149,13 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq); * quickly. Running on them for longer times may overheat the chip. * * Return: true if opp is turbo opp, else false. - * - * Locking: This function must be called under rcu_read_lock(). opp is a rcu - * protected pointer. This means that opp which could have been fetched by - * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are - * under RCU lock. The pointer returned by the opp_find_freq family must be - * used in the same section as the usage of this function with the pointer - * prior to unlocking with rcu_read_unlock() to maintain the integrity of the - * pointer. */ bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp) { struct dev_pm_opp *tmp_opp; + bool turbo; - opp_rcu_lockdep_assert(); + rcu_read_lock(); tmp_opp = rcu_dereference(opp); if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) { @@ -182,7 +163,10 @@ bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp) return false; } - return tmp_opp->turbo; + turbo = tmp_opp->turbo; + + rcu_read_unlock(); + return turbo; } EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo); @@ -410,11 +394,8 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count); * This provides a mechanism to enable an opp which is not available currently * or the opposite as well. * - * Locking: This function must be called under rcu_read_lock(). 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. + * The callers are required to call dev_pm_opp_put() for the returned OPP after + * use. */ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, unsigned long freq, @@ -423,13 +404,14 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, struct opp_table *opp_table; struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); - opp_rcu_lockdep_assert(); + rcu_read_lock(); opp_table = _find_opp_table(dev); if (IS_ERR(opp_table)) { int r = PTR_ERR(opp_table); dev_err(dev, "%s: OPP table not found (%d)\n", __func__, r); + rcu_read_unlock(); return ERR_PTR(r); } @@ -437,10 +419,15 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, if (temp_opp->available == available && temp_opp->rate == freq) { opp = temp_opp; + + /* Increment the reference count of OPP */ + dev_pm_opp_get(opp); break; } } + rcu_read_unlock(); + return opp; } EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact); @@ -454,6 +441,9 @@ static noinline struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table, if (temp_opp->available && temp_opp->rate >= *freq) { opp = temp_opp; *freq = opp->rate; + + /* Increment the reference count of OPP */ + dev_pm_opp_get(opp); break; } } @@ -476,29 +466,33 @@ static noinline struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table, * ERANGE: no match found for search * ENODEV: if device not found in list of registered devices * - * Locking: This function must be called under rcu_read_lock(). 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. + * The callers are required to call dev_pm_opp_put() for the returned OPP after + * use. */ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev, unsigned long *freq) { struct opp_table *opp_table; - - opp_rcu_lockdep_assert(); + struct dev_pm_opp *opp; if (!dev || !freq) { dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); return ERR_PTR(-EINVAL); } + rcu_read_lock(); + opp_table = _find_opp_table(dev); - if (IS_ERR(opp_table)) + if (IS_ERR(opp_table)) { + rcu_read_unlock(); return ERR_CAST(opp_table); + } + + opp = _find_freq_ceil(opp_table, freq); - return _find_freq_ceil(opp_table, freq); + rcu_read_unlock(); + + return opp; } EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil); @@ -517,11 +511,8 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil); * ERANGE: no match found for search * ENODEV: if device not found in list of registered devices * - * Locking: This function must be called under rcu_read_lock(). 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. + * The callers are required to call dev_pm_opp_put() for the returned OPP after + * use. */ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev, unsigned long *freq) @@ -529,16 +520,18 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev, struct opp_table *opp_table; struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); - opp_rcu_lockdep_assert(); - if (!dev || !freq) { dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); return ERR_PTR(-EINVAL); } + rcu_read_lock(); + opp_table = _find_opp_table(dev); - if (IS_ERR(opp_table)) + if (IS_ERR(opp_table)) { + rcu_read_unlock(); return ERR_CAST(opp_table); + } list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) { if (temp_opp->available) { @@ -549,6 +542,12 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev, opp = temp_opp; } } + + /* Increment the reference count of OPP */ + if (!IS_ERR(opp)) + dev_pm_opp_get(opp); + rcu_read_unlock(); + if (!IS_ERR(opp)) *freq = opp->rate; @@ -736,6 +735,8 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) ret = PTR_ERR(opp); dev_err(dev, "%s: failed to find OPP for freq %lu (%d)\n", __func__, freq, ret); + if (!IS_ERR(old_opp)) + dev_pm_opp_put(old_opp); rcu_read_unlock(); return ret; } @@ -747,6 +748,9 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) /* Only frequency scaling */ if (!regulators) { + dev_pm_opp_put(opp); + if (!IS_ERR(old_opp)) + dev_pm_opp_put(old_opp); rcu_read_unlock(); return _generic_set_opp_clk_only(dev, clk, old_freq, freq); } @@ -772,6 +776,9 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) data->new_opp.rate = freq; memcpy(data->new_opp.supplies, opp->supplies, size); + dev_pm_opp_put(opp); + if (!IS_ERR(old_opp)) + dev_pm_opp_put(old_opp); rcu_read_unlock(); return set_opp(data); @@ -967,6 +974,11 @@ static void _opp_kref_release(struct kref *kref) dev_pm_opp_put_opp_table(opp_table); } +static void dev_pm_opp_get(struct dev_pm_opp *opp) +{ + kref_get(&opp->kref); +} + void dev_pm_opp_put(struct dev_pm_opp *opp) { kref_put_mutex(&opp->kref, _opp_kref_release, &opp->opp_table->lock); |