iokit/IOKit/IOInterruptEventSource.h

   1 /*
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  28 /*
  29 Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
  30
  31 HISTORY
  32     1998-7-13   Godfrey van der Linden(gvdl)
  33         Created.
  34     1998-10-30  Godfrey van der Linden(gvdl)
  35         Converted to C++
  36 */
  37
  38 #ifndef _IOKIT_IOINTERRUPTEVENTSOURCE_H
  39 #define _IOKIT_IOINTERRUPTEVENTSOURCE_H
  40
  41 #include <IOKit/IOEventSource.h>
  42
  43 class IOService;
  44
  45 /*! @class IOInterruptEventSource : public IOEventSource
  46     @abstract Event source for interrupt delivery to work-loop based drivers.
  47     @discussion The IOInterruptEventSource is a generic object that delivers calls interrupt routines in it's client in a guaranteed single-threaded manner.  IOInterruptEventSource is part of the IOKit $link IOWorkLoop infrastructure where the semantic that one and only one action method is executing within a work-loops event chain.
  48 <br><br>
  49 When the action method is called in the client member function will receive 2 arguments, (IOEventSource *) sender and (int) count, See $link IOInterruptEventSource::Action.    Where sender will be reference to the interrupt that occurred and the count will be computed by the difference between the $link producerCount and $link consumerCount.  This number may not be reliable as no attempt is made to adjust for around the world type problems but is provided for general information and statistic gathering.
  50 <br><br>
  51 In general a client will use the factory member function to create and initialise the event source and then add it to their work-loop.  It is the work loop's responsiblity to maintain the new event source in it's event chain.  See $link IOWorkLoop.
  52 <br><br>
  53 An interrupt event source attaches itself to the given provider's interrupt source at initialisation time.  At this time it determines if it is connected to a level or edge triggered interrupt.  If the interrupt is an level triggered interrupt the event source automatically disables the interrupt source at primary interrupt time and after it call's the client it automatically reenables the interrupt.  This action is fairly expensive but it is 100% safe and defaults sensibly so that the driver writer does not have to implement type dependant interrupt routines.  So to repeat, the driver writer does not have to be concerned by the actual underlying interrupt mechanism as the event source hides the complexity.
  54 <br><br>
  55 Saying this if the hardware is a multi-device card, for instance a 4 port NIC, where all of the devices are sharing one level triggered interrupt AND it is possible to determine each port's interrupt state non-destructively then the $link IOFilterInterruptEventSource would be a better choice.
  56 <br><br>
  57 Warning:  All IOInterruptEventSources are created in the disabled state.  If you want to actually schedule interrupt delivery do not forget to enable the source.
  58 */
  59 class IOInterruptEventSource : public IOEventSource
  60 {
  61     OSDeclareDefaultStructors(IOInterruptEventSource)
  62
  63 public:
  64 /*! @typedef Action
  65     @discussion 'C' pointer prototype of functions that are called in a single threaded context when an interrupt occurs.
  66     @param owner Pointer to client instance.
  67     @param sender Pointer to generation interrupt event source.
  68     @param count Number of interrupts seen before delivery. */
  69     typedef void (*Action)(OSObject *, IOInterruptEventSource *, int count);
  70
  71 /*! @defined IOInterruptEventAction
  72     @discussion Backward compatibilty define for the old non-class scoped type definition.  See $link IOInterruptEventSource::Action */
  73 #define IOInterruptEventAction IOInterruptEventSource::Action
  74
  75 protected:
  76 /*! @var provider IOService that provides interrupts for delivery. */
  77     IOService *provider;
  78
  79 /*! @var intIndex */
  80     int intIndex;
  81
  82 /*! @var producerCount
  83     Current count of produced interrupts that have been received. */
  84     volatile unsigned int producerCount;
  85
  86 /*! @var consumerCount
  87     Current count of produced interrupts that the owner has been informed of. */
  88     unsigned int consumerCount;
  89
  90 /*! @var autoDisable Do we need to automatically disable the interrupt source when we take an interrupt, i.e. we are level triggered. */
  91     bool autoDisable;
  92
  93 /*! @var explicitDisable Has the user expicitly disabled this event source, if so then do not overide their request when returning from the callout */
  94     bool explicitDisable;
  95
  96 /*! @struct ExpansionData
  97     @discussion This structure will be used to expand the capablilties of the IOWorkLoop in the future.
  98     */
  99     struct ExpansionData { };
 100
 101 /*! @var reserved
 102     Reserved for future use.  (Internal use only)  */
 103     ExpansionData *reserved;
 104
 105 /*! @function free
 106     @abstract Sub-class implementation of free method, disconnects from the interrupt source. */
 107     virtual void free();
 108
 109 /*! @function checkForWork
 110     @abstract Pure Virtual member function used by IOWorkLoop for issueing a client calls.
 111     @discussion This function called when the work-loop is ready to check for any work to do and then to call out the owner/action.
 112     @result Return true if this function needs to be called again before all its outstanding events have been processed. */
 113     virtual bool checkForWork();
 114
 115 public:
 116
 117 /*! @function interruptEventSource
 118     @abstract Factory function for IOInterruptEventSources creation and initialisation.
 119     @param owner Owning client of the new event source.
 120     @param action 'C' Function to call when something happens.
 121     @param provider IOService that represents the interrupt source.  Defaults to 0.  When no provider is defined the event source assumes that the client will in some manner call the interruptOccured method explicitly.  This will start the ball rolling for safe delivery of asynchronous event's into the driver.
 122     @param intIndex The index of the interrupt within the provider's interrupt sources.  Defaults to 0, i.e. the first interrupt in the provider.
 123     @result A new interrupt event source if successfully created and initialised, 0 otherwise.  */
 124     static IOInterruptEventSource *
 125         interruptEventSource(OSObject *owner,
 126                              Action action,
 127                              IOService *provider = 0,
 128                              int intIndex = 0);
 129
 130 /*! @function init
 131     @abstract Primary initialiser for the IOInterruptEventSource class.
 132     @param owner Owning client of the new event source.
 133     @param action 'C' Function to call when something happens.
 134     @param provider IOService that represents the interrupt source.  Defaults to 0.  When no provider is defined the event source assumes that the client will in some manner call the interruptOccured method explicitly.  This will start the ball rolling for safe delivery of asynchronous event's into the driver.
 135     @param intIndex The index of the interrupt within the provider's interrupt sources.  Defaults to 0, i.e. the first interrupt in the provider.
 136     @result true if the inherited classes and this instance initialise
 137 successfully.  */
 138     virtual bool init(OSObject *owner,
 139                       Action action,
 140                       IOService *provider = 0,
 141                       int intIndex = 0);
 142
 143 /*! @function enable
 144     @abstract Enable event source.
 145     @discussion A subclass implementation is expected to respect the enabled
 146 state when checkForWork is called.  Calling this function will cause the
 147 work-loop to be signalled so that a checkForWork is performed. */
 148     virtual void enable();
 149
 150 /*! @function disable
 151     @abstract Disable event source.
 152     @discussion A subclass implementation is expected to respect the enabled
 153 state when checkForWork is called. */
 154     virtual void disable();
 155
 156 /*! @function getProvider
 157     @abstract Get'ter for $link provider variable.
 158     @result value of provider. */
 159     virtual const IOService *getProvider() const;
 160
 161 /*! @function getIntIndex
 162     @abstract Get'ter for $link intIndex interrupt index variable.
 163     @result value of intIndex. */
 164     virtual int getIntIndex() const;
 165
 166 /*! @function getAutoDisable
 167     @abstract Get'ter for $link autoDisable variable.
 168     @result value of autoDisable. */
 169     virtual bool getAutoDisable() const;
 170
 171 /*! @function interruptOccurred
 172     @abstract Functions that get called by the interrupt controller. See $link IOService::registerInterrupt
 173     @param nub Where did the interrupt originate from
 174     @param ind What is this interrupts index within 'nub'. */
 175     virtual void interruptOccurred(void *, IOService *nub, int ind);
 176
 177 /*! @function normalInterruptOccurred
 178     @abstract Functions that get called by the interrupt controller.See $link IOService::registerInterrupt
 179     @param nub Where did the interrupt originate from
 180     @param ind What is this interrupts index within 'nub'. */
 181     virtual void normalInterruptOccurred(void *, IOService *nub, int ind);
 182
 183 /*! @function disableInterruptOccurred
 184     @abstract Functions that get called by the interrupt controller.See $link IOService::registerInterrupt
 185     @param nub Where did the interrupt originate from
 186     @param ind What is this interrupts index within 'nub'. */
 187     virtual void disableInterruptOccurred(void *, IOService *nub, int ind);
 188
 189 private:
 190     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 0);
 191     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 1);
 192     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 2);
 193     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 3);
 194     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 4);
 195     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 5);
 196     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 6);
 197     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 7);
 198 };
 199
 200 #endif /* !_IOKIT_IOINTERRUPTEVENTSOURCE_H */