aboutsummaryrefslogtreecommitdiff
path: root/drivers/base/regmap/regmap.c
diff options
context:
space:
mode:
authorNicolas Boichat <drinkcat@chromium.org>2015-07-08 14:30:18 +0800
committerMark Brown <broonie@kernel.org>2015-08-07 14:50:59 +0100
commit3cfe7a74d42b7e3644f8b2b26aa20146d4f90f0f (patch)
treeab9efb80f6e886934d6e003582cd40d0cb9a2d34 /drivers/base/regmap/regmap.c
parent331a5fc9f2ed28033ddda89acb2a9b43592a545d (diff)
downloadlinux-linaro-stable-3cfe7a74d42b7e3644f8b2b26aa20146d4f90f0f.tar.gz
regmap: Use different lockdep class for each regmap init call
Lockdep validator complains about recursive locking and deadlock when two different regmap instances are called in a nested order. That happens anytime a regmap read/write call needs to access another regmap. This is because, for performance reason, lockdep groups all locks initialized by the same mutex_init() in the same lock class. Therefore all regmap mutexes are in the same lock class, leading to lockdep "nested locking" warnings if a regmap accesses another regmap. In general, it is impossible to establish in advance the hierarchy of regmaps, so we make sure that each regmap init call initializes its own static lock_class_key. This is done by wrapping all regmap_init calls into macros. This also allows us to give meaningful names to the lock_class_key. For example, in rt5677 case, we have in /proc/lockdep_chains: irq_context: 0 [ffffffc0018d2198] &dev->mutex [ffffffc0018d2198] &dev->mutex [ffffffc001bd7f60] rt5677:5104:(&rt5677_regmap)->_lock [ffffffc001bd7f58] rt5677:5096:(&rt5677_regmap_physical)->_lock [ffffffc001b95448] &(&base->lock)->rlock The above would have resulted in a lockdep recursive warning previously. This is not the case anymore as the lockdep validator now clearly identifies the 2 regmaps as separate. Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/base/regmap/regmap.c')
-rw-r--r--drivers/base/regmap/regmap.c31
1 files changed, 20 insertions, 11 deletions
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 7111d04f2621..b9fddccd6e06 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -527,10 +527,12 @@ EXPORT_SYMBOL_GPL(regmap_get_val_endian);
* a struct regmap. This function should generally not be called
* directly, it should be called by bus-specific init functions.
*/
-struct regmap *regmap_init(struct device *dev,
- const struct regmap_bus *bus,
- void *bus_context,
- const struct regmap_config *config)
+struct regmap *__regmap_init(struct device *dev,
+ const struct regmap_bus *bus,
+ void *bus_context,
+ const struct regmap_config *config,
+ struct lock_class_key *lock_key,
+ const char *lock_name)
{
struct regmap *map;
int ret = -EINVAL;
@@ -556,10 +558,14 @@ struct regmap *regmap_init(struct device *dev,
spin_lock_init(&map->spinlock);
map->lock = regmap_lock_spinlock;
map->unlock = regmap_unlock_spinlock;
+ lockdep_set_class_and_name(&map->spinlock,
+ lock_key, lock_name);
} else {
mutex_init(&map->mutex);
map->lock = regmap_lock_mutex;
map->unlock = regmap_unlock_mutex;
+ lockdep_set_class_and_name(&map->mutex,
+ lock_key, lock_name);
}
map->lock_arg = map;
}
@@ -899,7 +905,7 @@ err_map:
err:
return ERR_PTR(ret);
}
-EXPORT_SYMBOL_GPL(regmap_init);
+EXPORT_SYMBOL_GPL(__regmap_init);
static void devm_regmap_release(struct device *dev, void *res)
{
@@ -919,10 +925,12 @@ static void devm_regmap_release(struct device *dev, void *res)
* directly, it should be called by bus-specific init functions. The
* map will be automatically freed by the device management code.
*/
-struct regmap *devm_regmap_init(struct device *dev,
- const struct regmap_bus *bus,
- void *bus_context,
- const struct regmap_config *config)
+struct regmap *__devm_regmap_init(struct device *dev,
+ const struct regmap_bus *bus,
+ void *bus_context,
+ const struct regmap_config *config,
+ struct lock_class_key *lock_key,
+ const char *lock_name)
{
struct regmap **ptr, *regmap;
@@ -930,7 +938,8 @@ struct regmap *devm_regmap_init(struct device *dev,
if (!ptr)
return ERR_PTR(-ENOMEM);
- regmap = regmap_init(dev, bus, bus_context, config);
+ regmap = __regmap_init(dev, bus, bus_context, config,
+ lock_key, lock_name);
if (!IS_ERR(regmap)) {
*ptr = regmap;
devres_add(dev, ptr);
@@ -940,7 +949,7 @@ struct regmap *devm_regmap_init(struct device *dev,
return regmap;
}
-EXPORT_SYMBOL_GPL(devm_regmap_init);
+EXPORT_SYMBOL_GPL(__devm_regmap_init);
static void regmap_field_init(struct regmap_field *rm_field,
struct regmap *regmap, struct reg_field reg_field)