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unified: Add support for semaphore groups

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Semaphore groups are enabled by default. Disabling them will both
decrease the footprint as well as improve the performance of the
k_sem_give() routine.

Change-Id: If6c1b0e2e1f71afd43e620f05f17068039d12b05
Signed-off-by: Peter Mitsis <peter.mitsis@windriver.com>
This commit is contained in:
Peter Mitsis 2016-09-09 14:24:06 -04:00 • committed by Benjamin Walsh
commit 45403678aa
4 changed files with 295 additions and 19 deletions
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51
include/kernel.h
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@ -644,10 +644,53 @@ static inline int k_sem_count_get(struct k_sem *sem)
return sem->count;
}
extern struct k_sem *k_sem_group_take(struct k_sem **sem_array,
int32_t timeout);
extern void k_sem_group_give(struct k_sem **sem_array);
extern void k_sem_group_reset(struct k_sem **sem_array);
#ifdef CONFIG_SEMAPHORE_GROUPS
/**
* @brief Take the first available semaphore
*
* Given a list of semaphore pointers, this routine will attempt to take one
* of them, waiting up to a maximum of @a timeout ms to do so. The taken
* semaphore is identified by @a sem (set to NULL on error).
*
* Be aware that the more semaphores specified in the group, the more stack
* space is required by the waiting thread.
*
* @param sem_array Array of semaphore pointers terminated by a K_END entry
* @param sem Identifies the semaphore that was taken
* @param timeout Maximum number of milliseconds to wait
*
* @retval 0 A semaphore was successfully taken
* @retval -EBUSY No semaphore was available (@a timeout = K_NO_WAIT)
* @retval -EAGAIN Time out occurred while waiting for semaphore
*/
extern int k_sem_group_take(struct k_sem *sem_array[], struct k_sem **sem,
int32_t timeout);
/**
* @brief Give all the semaphores in the group
*
* This routine will give each semaphore in the array of semaphore pointers.
*
* @param sem_array Array of semaphore pointers terminated by a K_END entry
*
* @return N/A
*/
extern void k_sem_group_give(struct k_sem *sem_array[]);
/**
* @brief Reset the count to zero on each semaphore in the array
*
* This routine resets the count of each semaphore in the group to zero.
* Note that it does NOT have any impact on any thread that might have
* been previously pending on any of the semaphores.
*
* @param sem_array Array of semaphore pointers terminated by a K_END entry
*
* @return N/A
*/
extern void k_sem_group_reset(struct k_sem *sem_array[]);
#endif
#define K_SEM_INITIALIZER(obj, initial_count, count_limit) \
{ \