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hwspinlock: document the hwspinlock 'raw' API 

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.
::
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);
@ -184,6 +201,21 @@ Returns 0 on success and an appropriate error code otherwise (most
notably -EBUSY if the hwspinlock was already taken).
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);
@ -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
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);