Semaphore Functions

Functions that configure and use semaphoresSemaphore is very useful for multi-core cluster without SMP enable. More...

Functions
__STATIC_FORCEINLINE uint32_t	CIDU_GetSemaphoreStatus (uint32_t semph_n)
	Get SEMAPHOREn's value. More...
__STATIC_INLINE long	CIDU_CheckSemaphoreAcquired (uint32_t semph_n, uint32_t core_id)
	check SEMAPHOREn's acquired status More...
__STATIC_INLINE long	CIDU_AcquireSemaphore (uint32_t semph_n, uint32_t core_id)
	Acquire the SEMAPHOREn. More...
__STATIC_INLINE void	CIDU_AcquireSemaphore_Block (uint32_t semph_n, uint32_t core_id)
	Keep acquiring the SEMAPHOREn until it has acquired this semaphore successfully. More...
__STATIC_FORCEINLINE void	CIDU_ReleaseSemaphore (uint32_t semph_n)
	Release the SEMAPHOREn. More...

Detailed Description

Functions that configure and use semaphores

Semaphore is very useful for multi-core cluster without SMP enable.

• All Cores in the cluster agree on using SEMAPHORE_n register to protect a critical resource (an UART device for example).
• If Core n wants to access the critical resource, it should try to own the SEMPAPHORE_n register, or else it can’t access the critical resource.
• When the Core n owns the register SEMPAPHORE_n and finishes the job related the critical resource, then it should release the register by writing all 1 to it.

Function Documentation

CIDU_AcquireSemaphore()

__STATIC_INLINE long CIDU_AcquireSemaphore	(	uint32_t	semph_n,
		uint32_t	core_id
	)

Acquire the SEMAPHOREn.

Acuqire the SEMAPHOREn, and check the acquired status

Parameters

[in]	semph_n	the semaphore id used to protect a critical resource
[in]	core_id	the core id that wants to access the critical resource

Returns

0 if core_id has acquired this semaphore successfully, or else -1 if failed

Remarks

• When the core n owns the register SEMPAPHORE_n and finishes the job related the critical resource, it should call CIDU_ReleaseSemaphore to release it.

See also

• CIDU_CheckSemaphoreAcquired
• CIDU_ReleaseSemaphore

Definition at line 386 of file core_feature_cidu.h.

{
    long semaphore_status = -1;
    uint32_t* addr = (uint32_t*)CIDU_SEMAPHORE_ADDR(semph_n);
 
    __SW(addr, core_id);
    semaphore_status = CIDU_CheckSemaphoreAcquired(semph_n, core_id);
    return semaphore_status;
}

References __SW(), CIDU_CheckSemaphoreAcquired(), and CIDU_SEMAPHORE_ADDR.

Referenced by CIDU_AcquireSemaphore_Block().

CIDU_AcquireSemaphore_Block()

__STATIC_INLINE void CIDU_AcquireSemaphore_Block	(	uint32_t	semph_n,
		uint32_t	core_id
	)

Keep acquiring the SEMAPHOREn until it has acquired this semaphore successfully.

Query that whether SEMAPHOREn has been owned by one core successfully, if not, keep trying.

Parameters

[in]	semph_n	the semaphore id used to protect a critical resource
[in]	core_id	the core id that wants to access the critical resource

Remarks

• Core n will block here acquiring, so take care that core should release the semaphore when related job done.

See also

• CIDU_AcquireSemaphore
• CIDU_ReleaseSemaphore

Definition at line 408 of file core_feature_cidu.h.

{
    int32_t semaphore_status = -1;
 
    while(0 != semaphore_status) {
        semaphore_status = CIDU_AcquireSemaphore(semph_n, core_id);
    }
}

References CIDU_AcquireSemaphore().

CIDU_CheckSemaphoreAcquired()

__STATIC_INLINE long CIDU_CheckSemaphoreAcquired	(	uint32_t	semph_n,
		uint32_t	core_id
	)

check SEMAPHOREn's acquired status

Query that whether SEMAPHOREn has been acquired by one core successfully.

Parameters

[in]	semph_n	the semaphore id used to protect a critical resource
[in]	core_id	the core id that wants to access the critical resource

Returns

0 if core_id has acquired this semaphore successfully, or else -1 if failed

Remarks

• When the core n owns the register SEMPAPHORE_n and finishes the job related the critical resource, it should call CIDU_ReleaseSemaphore to release it.

See also

• CIDU_GetSemaphoreStatus
• CIDU_ReleaseSemaphore

Definition at line 362 of file core_feature_cidu.h.

{
    uint32_t val;
    val = CIDU_GetSemaphoreStatus(semph_n);
    if (core_id != val) {
        return -1;
    }
    return 0;
}

References CIDU_GetSemaphoreStatus().

Referenced by CIDU_AcquireSemaphore().

CIDU_GetSemaphoreStatus()

__STATIC_FORCEINLINE uint32_t CIDU_GetSemaphoreStatus

(

uint32_t

semph_n

)

Get SEMAPHOREn's value.

Just query the semaphore n's value

Parameters

[in]

semph_n

the semaphore id used to protect a critical resource

Returns

register SEMAPHOREn_STATUS value

Definition at line 339 of file core_feature_cidu.h.

{
    uint32_t val;
    uint32_t* addr = (uint32_t*)CIDU_SEMAPHORE_ADDR(semph_n);
 
    val = __LW(addr);
    return val;
}

References __LW(), and CIDU_SEMAPHORE_ADDR.

Referenced by CIDU_CheckSemaphoreAcquired().

CIDU_ReleaseSemaphore()

__STATIC_FORCEINLINE void CIDU_ReleaseSemaphore

(

uint32_t

semph_n

)

Release the SEMAPHOREn.

Release the SEMAPHOREn by writing all 1 to SEMAPHOREn register.

Parameters

[in]

semph_n

the semaphore id used to protect a critical resource

Remarks

• When the core finishes the job related to the critical resource, it should release the corresponding semaphore.

See also

• CIDU_AcquireSemaphore_Block

Definition at line 427 of file core_feature_cidu.h.

{
    uint32_t* addr = (uint32_t*)CIDU_SEMAPHORE_ADDR(semph_n);
 
    /* Release by writing all 1 */
    __SW(addr, 0xFFFFFFFF);
}

References __SW(), and CIDU_SEMAPHORE_ADDR.