Interrupt management.
[Xenomai nucleus.]

Collaboration diagram for Interrupt management.:

Detailed Description

Interrupt management.


Files

file  intr.c
 Interrupt management.

Functions

int xnintr_init (xnintr_t *intr, const char *name, unsigned irq, xnisr_t isr, xniack_t iack, xnflags_t flags)
 Initialize an interrupt object.
int xnintr_destroy (xnintr_t *intr)
 Destroy an interrupt object.
int xnintr_attach (xnintr_t *intr, void *cookie)
 Attach an interrupt object.
int xnintr_detach (xnintr_t *intr)
 Detach an interrupt object.
int xnintr_enable (xnintr_t *intr)
 Enable an interrupt object.
int xnintr_disable (xnintr_t *intr)
 Disable an interrupt object.
xnarch_cpumask_t xnintr_affinity (xnintr_t *intr, xnarch_cpumask_t cpumask)
 Set interrupt's processor affinity.


Function Documentation

xnarch_cpumask_t xnintr_affinity ( xnintr_t *  intr,
xnarch_cpumask_t  cpumask 
)

Set interrupt's processor affinity.

Causes the IRQ associated with the interrupt object intr to be received only on processors which bits are set in cpumask.

Parameters:
intr The descriptor address of the interrupt object which affinity is to be changed.
cpumask The new processor affinity of the interrupt object.
Returns:
the previous cpumask on success, or an empty mask on failure.
Note:
Depending on architectures, setting more than one bit in cpumask could be meaningless.

int xnintr_attach ( xnintr_t *  intr,
void *  cookie 
)

Attach an interrupt object.

Attach an interrupt object previously initialized by xnintr_init(). After this operation is completed, all IRQs received from the corresponding interrupt channel are directed to the object's ISR.

Parameters:
intr The descriptor address of the interrupt object to attach.
cookie A user-defined opaque value which is stored into the interrupt object descriptor for further retrieval by the ISR/ISR handlers.
Returns:
0 is returned on success. Otherwise, -EINVAL is returned if a low-level error occurred while attaching the interrupt. -EBUSY is specifically returned if the interrupt object was already attached.
Note:
The caller must not hold nklock when invoking this service, this would cause deadlocks.
Environments:

This service can be called from:

Rescheduling: never.

Note:
Attaching an interrupt resets the tracked number of receipts to zero.

int xnintr_destroy ( xnintr_t *  intr  ) 

Destroy an interrupt object.

Destroys an interrupt object previously initialized by xnintr_init(). The interrupt object is automatically detached by a call to xnintr_detach(). No more IRQs will be dispatched by this object after this service has returned.

Parameters:
intr The descriptor address of the interrupt object to destroy.
Returns:
0 is returned on success. Otherwise, -EBUSY is returned if an error occurred while detaching the interrupt (see xnintr_detach()).
Environments:

This service can be called from:

Rescheduling: never.

int xnintr_detach ( xnintr_t *  intr  ) 

Detach an interrupt object.

Detach an interrupt object previously attached by xnintr_attach(). After this operation is completed, no more IRQs are directed to the object's ISR, but the interrupt object itself remains valid. A detached interrupt object can be attached again by a subsequent call to xnintr_attach().

Parameters:
intr The descriptor address of the interrupt object to detach.
Returns:
0 is returned on success. Otherwise, -EINVAL is returned if a low-level error occurred while detaching the interrupt. Detaching a non-attached interrupt object leads to a null-effect and returns 0.
Note:
The caller must not hold nklock when invoking this service, this would cause deadlocks.
Environments:

This service can be called from:

Rescheduling: never.

int xnintr_disable ( xnintr_t *  intr  ) 

Disable an interrupt object.

Disables the hardware interrupt line associated with an interrupt object. This operation invalidates further interrupt requests from the given source until the IRQ line is re-enabled anew.

Parameters:
intr The descriptor address of the interrupt object to disable.
Returns:
0 is returned on success. Otherwise, -EINVAL is returned if a low-level error occurred while disabling the interrupt.
Environments:

This service can be called from:

Rescheduling: never.

int xnintr_enable ( xnintr_t *  intr  ) 

Enable an interrupt object.

Enables the hardware interrupt line associated with an interrupt object. Over real-time control layers which mask and acknowledge IRQs, this operation is necessary to revalidate the interrupt channel so that more interrupts can be notified.

Parameters:
intr The descriptor address of the interrupt object to enable.
Returns:
0 is returned on success. Otherwise, -EINVAL is returned if a low-level error occurred while enabling the interrupt.
Environments:

This service can be called from:

Rescheduling: never.

int xnintr_init ( xnintr_t *  intr,
const char *  name,
unsigned  irq,
xnisr_t  isr,
xniack_t  iack,
xnflags_t  flags 
)

Initialize an interrupt object.

Associates an interrupt object with an IRQ line.

When an interrupt occurs on the given irq line, the ISR is fired in order to deal with the hardware event. The interrupt service code may call any non-suspensive service from the nucleus.

Upon receipt of an IRQ, the ISR is immediately called on behalf of the interrupted stack context, the rescheduling procedure is locked, and the interrupt source is masked at hardware level. The status value returned by the ISR is then checked for the following values:

In addition, one of the following bits may be set by the ISR :

NOTE: use these bits with care and only when you do understand their effect on the system. The ISR is not encouraged to use these bits in case it shares the IRQ line with other ISRs in the real-time domain.

The nucleus re-enables the IRQ line by default. Over some real-time control layers which mask and acknowledge IRQs, this operation is necessary to revalidate the interrupt channel so that more interrupts can be notified.

A count of interrupt receipts is tracked into the interrupt descriptor, and reset to zero each time the interrupt object is attached. Since this count could wrap around, it should be used as an indication of interrupt activity only.

Parameters:
intr The address of a interrupt object descriptor the nucleus will use to store the object-specific data. This descriptor must always be valid while the object is active therefore it must be allocated in permanent memory.
name An ASCII string standing for the symbolic name of the interrupt object or NULL ("<unknown>" will be applied then).
irq The hardware interrupt channel associated with the interrupt object. This value is architecture-dependent. An interrupt object must then be attached to the hardware interrupt vector using the xnintr_attach() service for the associated IRQs to be directed to this object.
isr The address of a valid low-level interrupt service routine if this parameter is non-zero. This handler will be called each time the corresponding IRQ is delivered on behalf of an interrupt context. When called, the ISR is passed the descriptor address of the interrupt object.
iack The address of an optional interrupt acknowledge routine, aimed at replacing the default one. Only very specific situations actually require to override the default setting for this parameter, like having to acknowledge non-standard PIC hardware. iack should return a non-zero value to indicate that the interrupt has been properly acknowledged. If iack is NULL, the default routine will be used instead.
flags A set of creation flags affecting the operation. The valid flags are:

Returns:
No error condition being defined, 0 is always returned.
Environments:

This service can be called from:

Rescheduling: never.


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