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IOFilterInterruptEventSource

Overview

Filtering varient of the IOInterruptEventSource.

Discussion

An interrupt event source that calls the client to determine if a interrupt event needs to be scheduled on the work loop. A filter interrupt event source call's the client in the primary interrupt context, the client can then interrogate its hardware and determine if the interrupt needs to be processed yet.

As the routine is called in the primary interrupt context great care must be taken in the writing of this routine. In general none of the generic IOKit environment is safe to call in this context. We intend this routine to be used by hardware that can interrogate its registers without destroying state. Primarily this variant of event sources will be used by drivers that share interrupts. The filter routine will determine if the interrupt is a real interrupt or a ghost and thus optimise the work thread context switch away.

CAUTION: Called in primary interrupt context, if you need to disable interrupt to guard you registers against an unexpected call then it is better to use a straight IOInterruptEventSource and its secondary interrupt delivery mechanism.

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Functions

disableInterruptOccurred

Override IOInterruptEventSource::disableInterruptOccurred to make a filter callout.

filterInterruptEventSource

Factor method to create and initialise an IOFilterInterruptEventSource. See init.

getFilterAction

Get'ter for filterAction variable.

init

Primary initialiser for the IOFilterInterruptEventSource class.

normalInterruptOccurred

Override IOInterruptEventSource::normalInterruptOccured to make a filter callout.

signalInterrupt

Cause the work loop to schedule the action.

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disableInterruptOccurred

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Override IOInterruptEventSource::disableInterruptOccurred to make a filter callout.

public

virtual void disableInterruptOccurred(
    void *self,
    IOService *prov,
    int ind); 

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filterInterruptEventSource

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Factor method to create and initialise an IOFilterInterruptEventSource. See init.

public

static IOFilterInterruptEventSource * filterInterruptEventSource(
    OSObject *owner, 
    IOInterruptEventSource::Action action, 
    Filter filter, 
    IOService *provider, 
    int intIndex = 0); 

Parameters

owner

Owner/client of this event source.

action

'C' Function to call when something happens.

filter

'C' Function to call when interrupt occurs.

provider

Service that provides interrupts.

intIndex

Defaults to 0.

Return Value

a new event source if succesful, 0 otherwise.

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getFilterAction

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Get'ter for filterAction variable.

public

virtual Filter getFilterAction() const; 

Return Value

value of filterAction.

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init

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Primary initialiser for the IOFilterInterruptEventSource class.

public

virtual bool init(
    OSObject *owner, 
    IOInterruptEventSource::Action action, 
    Filter filter, 
    IOService *provider, 
    int intIndex = 0); 

Parameters

owner

Owner/client of this event source.

action

'C' Function to call when something happens.

filter

'C' Function to call in primary interrupt context.

provider

Service that provides interrupts.

intIndex

Interrupt source within provider. Defaults to 0.

Return Value

true if the inherited classes and this instance initialise successfully.

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normalInterruptOccurred

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Override IOInterruptEventSource::normalInterruptOccured to make a filter callout.

public

virtual void normalInterruptOccurred(
    void *self,
    IOService *prov,
    int ind); 

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signalInterrupt

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Cause the work loop to schedule the action.

public

virtual void signalInterrupt(); 

Discussion

Cause the work loop to schedule the interrupt action even if the filter routine returns 'false'. Note well the interrupting condition MUST be cleared from the hardware otherwise an infinite process interrupt loop will occur. Use this function when 'SoftDMA' is desired. See IOFilterInterruptSource::Filter

Typedefs

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Filter

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public

typedef bool ( *Filter)(
    OSObject *,
    IOFilterInterruptEventSource *); 

Parameters

owner

Pointer to the owning/client instance.

sender

Where is the interrupt comming from.

Return Value

false if this interrupt can be ignored.

Discussion

C Function pointer to a routine to call when an interrupt occurs.

Structs and Unions

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ExpansionData

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protected

struct ExpansionData {
}; 

Discussion

This structure will be used to expand the capablilties of the IOWorkLoop in the future.

Member Data

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filterAction

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Filter callout

protected

Filter filterAction; 

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reserved

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protected

ExpansionData *reserved; 

Discussion

Reserved for future use. (Internal use only)

#defines

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IOFilterInterruptAction

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#define IOFilterInterruptAction IOFilterInterruptEventSource::Filter 

Discussion

Backward compatibilty define for the old non-class scoped type definition. See IOFilterInterruptSource::Filter

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Last Updated: 2008-12-19