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hwspinlock: document the hwspinlock 'raw' API

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Document the hwspin_lock_timeout_raw(), hwspin_trylock_raw() and
hwspin_unlock_raw() API.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
This commit is contained in:
Fabien Dessenne 2019-03-07 16:58:22 +01:00 committed by Bjorn Andersson
parent 5cd69f13de
commit bce6f52213
1 changed files with 42 additions and 0 deletions
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42
Documentation/hwspinlock.txt
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@ -134,6 +134,23 @@ notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs).
The function will never sleep. The function will never sleep.
::
int hwspin_lock_timeout_raw(struct hwspinlock *hwlock, unsigned int timeout);
Lock a previously-assigned hwspinlock with a timeout limit (specified in
msecs). If the hwspinlock is already taken, the function will busy loop
waiting for it to be released, but give up when the timeout elapses.
Caution: User must protect the routine of getting hardware lock with mutex
or spinlock to avoid dead-lock, that will let user can do some time-consuming
or sleepable operations under the hardware lock.
Returns 0 when successful and an appropriate error code otherwise (most
notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs).
The function will never sleep.
:: ::
int hwspin_trylock(struct hwspinlock *hwlock); int hwspin_trylock(struct hwspinlock *hwlock);
@ -184,6 +201,21 @@ Returns 0 on success and an appropriate error code otherwise (most
notably -EBUSY if the hwspinlock was already taken). notably -EBUSY if the hwspinlock was already taken).
The function will never sleep. The function will never sleep.
::
int hwspin_trylock_raw(struct hwspinlock *hwlock);
Attempt to lock a previously-assigned hwspinlock, but immediately fail if
it is already taken.
Caution: User must protect the routine of getting hardware lock with mutex
or spinlock to avoid dead-lock, that will let user can do some time-consuming
or sleepable operations under the hardware lock.
Returns 0 on success and an appropriate error code otherwise (most
notably -EBUSY if the hwspinlock was already taken).
The function will never sleep.
:: ::
void hwspin_unlock(struct hwspinlock *hwlock); void hwspin_unlock(struct hwspinlock *hwlock);
@ -220,6 +252,16 @@ Upon a successful return from this function, preemption is reenabled,
and the state of the local interrupts is restored to the state saved at and the state of the local interrupts is restored to the state saved at
the given flags. This function will never sleep. the given flags. This function will never sleep.
::
void hwspin_unlock_raw(struct hwspinlock *hwlock);
Unlock a previously-locked hwspinlock.
The caller should **never** unlock an hwspinlock which is already unlocked.
Doing so is considered a bug (there is no protection against this).
This function will never sleep.
:: ::
int hwspin_lock_get_id(struct hwspinlock *hwlock); int hwspin_lock_get_id(struct hwspinlock *hwlock);