iokit/IOKit/IOInterruptEventSource.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
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   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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  20  * Please see the License for the specific language governing rights and
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  25 /*
  26 Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
  27
  28 HISTORY
  29     1998-7-13   Godfrey van der Linden(gvdl)
  30         Created.
  31     1998-10-30  Godfrey van der Linden(gvdl)
  32         Converted to C++
  33 */
  34
  35 #ifndef _IOKIT_IOINTERRUPTEVENTSOURCE_H
  36 #define _IOKIT_IOINTERRUPTEVENTSOURCE_H
  37
  38 #include <IOKit/IOEventSource.h>
  39
  40 class IOService;
  41
  42 /*! @class IOInterruptEventSource : public IOEventSource
  43     @abstract Event source for interrupt delivery to work-loop based drivers.
  44     @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.
  45 <br><br>
  46 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 occured 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.
  47 <br><br>
  48 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.
  49 <br><br>
  50 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.
  51 <br><br>
  52 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.
  53 <br><br>
  54 Warning:  All IOInterruptEventSources are created in the disabled state.  If you want to actually schedule interrupt delivery do not forget to enable the source.
  55 */
  56 class IOInterruptEventSource : public IOEventSource
  57 {
  58     OSDeclareDefaultStructors(IOInterruptEventSource)
  59
  60 public:
  61 /*! @typedef Action
  62     @discussion 'C' pointer prototype of functions that are called in a single threaded context when an interrupt occurs.
  63     @param owner Pointer to client instance.
  64     @param sender Pointer to generation interrupt event source.
  65     @param count Number of interrupts seen before delivery. */
  66     typedef void (*Action)(OSObject *, IOInterruptEventSource *, int count);
  67
  68 /*! @defined IOInterruptEventAction
  69     @discussion Backward compatibilty define for the old non-class scoped type definition.  See $link IOInterruptEventSource::Action */
  70 #define IOInterruptEventAction IOInterruptEventSource::Action
  71
  72 protected:
  73 /*! @var provider IOService that provides interrupts for delivery. */
  74     IOService *provider;
  75
  76 /*! @var intIndex */
  77     int intIndex;
  78
  79 /*! @var producerCount
  80     Current count of produced interrupts that have been received. */
  81     volatile unsigned int producerCount;
  82
  83 /*! @var consumerCount
  84     Current count of produced interrupts that the owner has been informed of. */
  85     unsigned int consumerCount;
  86
  87 /*! @var autoDisable Do we need to automatically disable the interrupt source when we take an interrupt, i.e. we are level triggered. */
  88     bool autoDisable;
  89
  90 /*! @var explicitDisable Has the user expicitly disabled this event source, if so then do not overide their request when returning from the callout */
  91     bool explicitDisable;
  92
  93 /*! @struct ExpansionData
  94     @discussion This structure will be used to expand the capablilties of the IOWorkLoop in the future.
  95     */
  96     struct ExpansionData { };
  97
  98 /*! @var reserved
  99     Reserved for future use.  (Internal use only)  */
 100     ExpansionData *reserved;
 101
 102 /*! @function free
 103     @abstract Sub-class implementation of free method, disconnects from the interrupt source. */
 104     virtual void free();
 105
 106 /*! @function checkForWork
 107     @abstract Pure Virtual member function used by IOWorkLoop for issueing a client calls.
 108     @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.
 109     @result Return true if this function needs to be called again before all its outstanding events have been processed. */
 110     virtual bool checkForWork();
 111
 112 public:
 113
 114 /*! @function interruptEventSource
 115     @abstract Factory function for IOInterruptEventSources creation and initialisation.
 116     @param owner Owning client of the new event source.
 117     @param action 'C' Function to call when something happens.
 118     @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.
 119     @param intIndex The index of the interrupt within the provider's interrupt sources.  Defaults to 0, i.e. the first interrupt in the provider.
 120     @result A new interrupt event source if successfully created and initialised, 0 otherwise.  */
 121     static IOInterruptEventSource *
 122         interruptEventSource(OSObject *owner,
 123                              Action action,
 124                              IOService *provider = 0,
 125                              int intIndex = 0);
 126
 127 /*! @function init
 128     @abstract Primary initialiser for the IOInterruptEventSource class.
 129     @param owner Owning client of the new event source.
 130     @param action 'C' Function to call when something happens.
 131     @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.
 132     @param intIndex The index of the interrupt within the provider's interrupt sources.  Defaults to 0, i.e. the first interrupt in the provider.
 133     @result true if the inherited classes and this instance initialise
 134 successfully.  */
 135     virtual bool init(OSObject *owner,
 136                       Action action,
 137                       IOService *provider = 0,
 138                       int intIndex = 0);
 139
 140 /*! @function enable
 141     @abstract Enable event source.
 142     @discussion A subclass implementation is expected to respect the enabled
 143 state when checkForWork is called.  Calling this function will cause the
 144 work-loop to be signalled so that a checkForWork is performed. */
 145     virtual void enable();
 146
 147 /*! @function disable
 148     @abstract Disable event source.
 149     @discussion A subclass implementation is expected to respect the enabled
 150 state when checkForWork is called. */
 151     virtual void disable();
 152
 153 /*! @function getProvider
 154     @abstract Get'ter for $link provider variable.
 155     @result value of provider. */
 156     virtual const IOService *getProvider() const;
 157
 158 /*! @function getIntIndex
 159     @abstract Get'ter for $link intIndex interrupt index variable.
 160     @result value of intIndex. */
 161     virtual int getIntIndex() const;
 162
 163 /*! @function getAutoDisable
 164     @abstract Get'ter for $link autoDisable variable.
 165     @result value of autoDisable. */
 166     virtual bool getAutoDisable() const;
 167
 168 /*! @function interruptOccurred
 169     @abstract Functions that get called by the interrupt controller. See $link IOService::registerInterrupt
 170     @param nub Where did the interrupt originate from
 171     @param ind What is this interrupts index within 'nub'. */
 172     virtual void interruptOccurred(void *, IOService *nub, int ind);
 173
 174 /*! @function normalInterruptOccurred
 175     @abstract Functions that get called by the interrupt controller.See $link IOService::registerInterrupt
 176     @param nub Where did the interrupt originate from
 177     @param ind What is this interrupts index within 'nub'. */
 178     virtual void normalInterruptOccurred(void *, IOService *nub, int ind);
 179
 180 /*! @function disableInterruptOccurred
 181     @abstract Functions that get called by the interrupt controller.See $link IOService::registerInterrupt
 182     @param nub Where did the interrupt originate from
 183     @param ind What is this interrupts index within 'nub'. */
 184     virtual void disableInterruptOccurred(void *, IOService *nub, int ind);
 185
 186 private:
 187     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 0);
 188     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 1);
 189     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 2);
 190     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 3);
 191     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 4);
 192     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 5);
 193     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 6);
 194     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 7);
 195 };
 196
 197 #endif /* !_IOKIT_IOINTERRUPTEVENTSOURCE_H */