iokit/IOKit/IOInterruptEventSource.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
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   8  * Version 2.0 (the 'License'). You may not use this file except in
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  20  * The Original Code and all software distributed under the License are
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  30 /*
  31 Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
  32
  33 HISTORY
  34     1998-7-13   Godfrey van der Linden(gvdl)
  35         Created.
  36     1998-10-30  Godfrey van der Linden(gvdl)
  37         Converted to C++
  38 */
  39
  40 #ifndef _IOKIT_IOINTERRUPTEVENTSOURCE_H
  41 #define _IOKIT_IOINTERRUPTEVENTSOURCE_H
  42
  43 #include <IOKit/IOEventSource.h>
  44
  45 class IOService;
  46
  47 /*! @class IOInterruptEventSource : public IOEventSource
  48     @abstract Event source for interrupt delivery to work-loop based drivers.
  49     @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.
  50 <br><br>
  51 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.
  52 <br><br>
  53 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.
  54 <br><br>
  55 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.
  56 <br><br>
  57 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.
  58 <br><br>
  59 Warning:  All IOInterruptEventSources are created in the disabled state.  If you want to actually schedule interrupt delivery do not forget to enable the source.
  60 */
  61 class IOInterruptEventSource : public IOEventSource
  62 {
  63     OSDeclareDefaultStructors(IOInterruptEventSource)
  64
  65 public:
  66 /*! @typedef Action
  67     @discussion 'C' pointer prototype of functions that are called in a single threaded context when an interrupt occurs.
  68     @param owner Pointer to client instance.
  69     @param sender Pointer to generation interrupt event source.
  70     @param count Number of interrupts seen before delivery. */
  71     typedef void (*Action)(OSObject *, IOInterruptEventSource *, int count);
  72
  73 /*! @defined IOInterruptEventAction
  74     @discussion Backward compatibilty define for the old non-class scoped type definition.  See $link IOInterruptEventSource::Action */
  75 #define IOInterruptEventAction IOInterruptEventSource::Action
  76
  77 protected:
  78 /*! @var provider IOService that provides interrupts for delivery. */
  79     IOService *provider;
  80
  81 /*! @var intIndex */
  82     int intIndex;
  83
  84 /*! @var producerCount
  85     Current count of produced interrupts that have been received. */
  86     volatile unsigned int producerCount;
  87
  88 /*! @var consumerCount
  89     Current count of produced interrupts that the owner has been informed of. */
  90     unsigned int consumerCount;
  91
  92 /*! @var autoDisable Do we need to automatically disable the interrupt source when we take an interrupt, i.e. we are level triggered. */
  93     bool autoDisable;
  94
  95 /*! @var explicitDisable Has the user expicitly disabled this event source, if so then do not overide their request when returning from the callout */
  96     bool explicitDisable;
  97
  98 /*! @struct ExpansionData
  99     @discussion This structure will be used to expand the capablilties of the IOWorkLoop in the future.
 100     */
 101     struct ExpansionData { };
 102
 103 /*! @var reserved
 104     Reserved for future use.  (Internal use only)  */
 105     ExpansionData *reserved;
 106
 107 /*! @function free
 108     @abstract Sub-class implementation of free method, disconnects from the interrupt source. */
 109     virtual void free();
 110
 111 /*! @function checkForWork
 112     @abstract Pure Virtual member function used by IOWorkLoop for issueing a client calls.
 113     @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.
 114     @result Return true if this function needs to be called again before all its outstanding events have been processed. */
 115     virtual bool checkForWork();
 116
 117 public:
 118
 119 /*! @function interruptEventSource
 120     @abstract Factory function for IOInterruptEventSources creation and initialisation.
 121     @param owner Owning client of the new event source.
 122     @param action 'C' Function to call when something happens.
 123     @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.
 124     @param intIndex The index of the interrupt within the provider's interrupt sources.  Defaults to 0, i.e. the first interrupt in the provider.
 125     @result A new interrupt event source if successfully created and initialised, 0 otherwise.  */
 126     static IOInterruptEventSource *
 127         interruptEventSource(OSObject *owner,
 128                              Action action,
 129                              IOService *provider = 0,
 130                              int intIndex = 0);
 131
 132 /*! @function init
 133     @abstract Primary initialiser for the IOInterruptEventSource class.
 134     @param owner Owning client of the new event source.
 135     @param action 'C' Function to call when something happens.
 136     @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.
 137     @param intIndex The index of the interrupt within the provider's interrupt sources.  Defaults to 0, i.e. the first interrupt in the provider.
 138     @result true if the inherited classes and this instance initialise
 139 successfully.  */
 140     virtual bool init(OSObject *owner,
 141                       Action action,
 142                       IOService *provider = 0,
 143                       int intIndex = 0);
 144
 145 /*! @function enable
 146     @abstract Enable event source.
 147     @discussion A subclass implementation is expected to respect the enabled
 148 state when checkForWork is called.  Calling this function will cause the
 149 work-loop to be signalled so that a checkForWork is performed. */
 150     virtual void enable();
 151
 152 /*! @function disable
 153     @abstract Disable event source.
 154     @discussion A subclass implementation is expected to respect the enabled
 155 state when checkForWork is called. */
 156     virtual void disable();
 157
 158 /*! @function getProvider
 159     @abstract Get'ter for $link provider variable.
 160     @result value of provider. */
 161     virtual const IOService *getProvider() const;
 162
 163 /*! @function getIntIndex
 164     @abstract Get'ter for $link intIndex interrupt index variable.
 165     @result value of intIndex. */
 166     virtual int getIntIndex() const;
 167
 168 /*! @function getAutoDisable
 169     @abstract Get'ter for $link autoDisable variable.
 170     @result value of autoDisable. */
 171     virtual bool getAutoDisable() const;
 172
 173 /*! @function interruptOccurred
 174     @abstract Functions that get called by the interrupt controller. See $link IOService::registerInterrupt
 175     @param nub Where did the interrupt originate from
 176     @param ind What is this interrupts index within 'nub'. */
 177     virtual void interruptOccurred(void *, IOService *nub, int ind);
 178
 179 /*! @function normalInterruptOccurred
 180     @abstract Functions that get called by the interrupt controller.See $link IOService::registerInterrupt
 181     @param nub Where did the interrupt originate from
 182     @param ind What is this interrupts index within 'nub'. */
 183     virtual void normalInterruptOccurred(void *, IOService *nub, int ind);
 184
 185 /*! @function disableInterruptOccurred
 186     @abstract Functions that get called by the interrupt controller.See $link IOService::registerInterrupt
 187     @param nub Where did the interrupt originate from
 188     @param ind What is this interrupts index within 'nub'. */
 189     virtual void disableInterruptOccurred(void *, IOService *nub, int ind);
 190
 191 private:
 192     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 0);
 193     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 1);
 194     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 2);
 195     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 3);
 196     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 4);
 197     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 5);
 198     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 6);
 199     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 7);
 200 };
 201
 202 #endif /* !_IOKIT_IOINTERRUPTEVENTSOURCE_H */