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regmap: Make regmap-mmio usable from atomic contexts

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regmap-mmio uses a spinlock with spin_lock() and spin_unlock() for locking.
To be able to use the regmap API from different contexts (atomic vs non-atomic),
without the risk of race conditions, we need to use spin_lock_irqsave() and
spin_lock_irqrestore() instead. A new field, the spinlock_flags field, is added
to regmap struct to store the flags between regmap_{,un}lock_spinlock(). The
spinlock_flags field itself is also protected by the spinlock.

Thanks to Stephen Warren for the suggestion of this particular solution.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Lars-Peter Clausen 2013-05-24 10:29:22 +02:00 committed by Mark Brown
parent 81485f5220
commit 92ab1aab59
2 changed files with 6 additions and 2 deletions
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1
drivers/base/regmap/internal.h
View File

@ -52,6 +52,7 @@ struct regmap_async {
struct regmap {
struct mutex mutex;
spinlock_t spinlock;
unsigned long spinlock_flags;
regmap_lock lock;
regmap_unlock unlock;
void *lock_arg; /* This is passed to lock/unlock functions */

7
drivers/base/regmap/regmap.c
View File

@ -302,13 +302,16 @@ static void regmap_unlock_mutex(void *__map)
static void regmap_lock_spinlock(void *__map)
{
struct regmap *map = __map;
spin_lock(&map->spinlock);
unsigned long flags;
spin_lock_irqsave(&map->spinlock, flags);
map->spinlock_flags = flags;
}
static void regmap_unlock_spinlock(void *__map)
{
struct regmap *map = __map;
spin_unlock(&map->spinlock);
spin_unlock_irqrestore(&map->spinlock, map->spinlock_flags);
}
static void dev_get_regmap_release(struct device *dev, void *res)