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Commit 92ab1aab authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Mark Brown
Browse files

regmap: Make regmap-mmio usable from atomic contexts 



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: default avatarLars-Peter Clausen <lars@metafoo.de>
Reviewed-by: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent 81485f52

drivers/base/regmap/internal.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -52,6 +52,7 @@ struct regmap_async { 
struct regmap {

struct regmap {

	struct mutex mutex;

	struct mutex mutex;

	spinlock_t spinlock;

	spinlock_t spinlock;

	unsigned long spinlock_flags;

	regmap_lock lock;

	regmap_lock lock;

	regmap_unlock unlock;

	regmap_unlock unlock;

	void *lock_arg; /* This is passed to lock/unlock functions */

	void *lock_arg; /* This is passed to lock/unlock functions */

drivers/base/regmap/regmap.c

+5 −2
Original line number Original line Diff line number Diff line
@@ -302,13 +302,16 @@ static void regmap_unlock_mutex(void *__map) 
static void regmap_lock_spinlock(void *__map)

static void regmap_lock_spinlock(void *__map)

{

{

	struct regmap *map = __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)

static void regmap_unlock_spinlock(void *__map)

{

{

	struct regmap *map = __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)

static void dev_get_regmap_release(struct device *dev, void *res)