iokit/IOKit/IOInterruptEventSource.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24 Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
  25
  26 HISTORY
  27     1998-7-13   Godfrey van der Linden(gvdl)
  28         Created.
  29     1998-10-30  Godfrey van der Linden(gvdl)
  30         Converted to C++
  31 */
  32
  33 #ifndef _IOKIT_IOINTERRUPTEVENTSOURCE_H
  34 #define _IOKIT_IOINTERRUPTEVENTSOURCE_H
  35
  36 #include <IOKit/IOEventSource.h>
  37
  38 class IOService;
  39
  40 /*! @class IOInterruptEventSource : public IOEventSource
  41     @abstract Event source for interrupt delivery to work-loop based drivers.
  42     @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.
  43 <br><br>
  44 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.
  45 <br><br>
  46 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.
  47 <br><br>
  48 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.
  49 <br><br>
  50 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.
  51 <br><br>
  52 Warning:  All IOInterruptEventSources are created in the disabled state.  If you want to actually schedule interrupt delivery do not forget to enable the source.
  53 */
  54 class IOInterruptEventSource : public IOEventSource
  55 {
  56     OSDeclareDefaultStructors(IOInterruptEventSource)
  57
  58 public:
  59 /*! @typedef Action
  60     @discussion 'C' pointer prototype of functions that are called in a single threaded context when an interrupt occurs.
  61     @param owner Pointer to client instance.
  62     @param sender Pointer to generation interrupt event source.
  63     @param count Number of interrupts seen before delivery. */
  64     typedef void (*Action)(OSObject *, IOInterruptEventSource *, int count);
  65
  66 /*! @defined IOInterruptEventAction
  67     @discussion Backward compatibilty define for the old non-class scoped type definition.  See $link IOInterruptEventSource::Action */
  68 #define IOInterruptEventAction IOInterruptEventSource::Action
  69
  70 protected:
  71 /*! @var provider IOService that provides interrupts for delivery. */
  72     IOService *provider;
  73
  74 /*! @var intIndex */
  75     int intIndex;
  76
  77 /*! @var producerCount
  78     Current count of produced interrupts that have been received. */
  79     volatile unsigned int producerCount;
  80
  81 /*! @var consumerCount
  82     Current count of produced interrupts that the owner has been informed of. */
  83     unsigned int consumerCount;
  84
  85 /*! @var autoDisable Do we need to automatically disable the interrupt source when we take an interrupt, i.e. we are level triggered. */
  86     bool autoDisable;
  87
  88 /*! @var explicitDisable Has the user expicitly disabled this event source, if so then do not overide their request when returning from the callout */
  89     bool explicitDisable;
  90
  91 /*! @struct ExpansionData
  92     @discussion This structure will be used to expand the capablilties of the IOWorkLoop in the future.
  93     */
  94     struct ExpansionData { };
  95
  96 /*! @var reserved
  97     Reserved for future use.  (Internal use only)  */
  98     ExpansionData *reserved;
  99
 100 /*! @function free
 101     @abstract Sub-class implementation of free method, disconnects from the interrupt source. */
 102     virtual void free();
 103
 104 /*! @function checkForWork
 105     @abstract Pure Virtual member function used by IOWorkLoop for issueing a client calls.
 106     @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.
 107     @result Return true if this function needs to be called again before all its outstanding events have been processed. */
 108     virtual bool checkForWork();
 109
 110 public:
 111
 112 /*! @function interruptEventSource
 113     @abstract Factory function for IOInterruptEventSources creation and initialisation.
 114     @param owner Owning client of the new event source.
 115     @param action 'C' Function to call when something happens.
 116     @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.
 117     @param intIndex The index of the interrupt within the provider's interrupt sources.  Defaults to 0, i.e. the first interrupt in the provider.
 118     @result A new interrupt event source if successfully created and initialised, 0 otherwise.  */
 119     static IOInterruptEventSource *
 120         interruptEventSource(OSObject *owner,
 121                              Action action,
 122                              IOService *provider = 0,
 123                              int intIndex = 0);
 124
 125 /*! @function init
 126     @abstract Primary initialiser for the IOInterruptEventSource class.
 127     @param owner Owning client of the new event source.
 128     @param action 'C' Function to call when something happens.
 129     @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.
 130     @param intIndex The index of the interrupt within the provider's interrupt sources.  Defaults to 0, i.e. the first interrupt in the provider.
 131     @result true if the inherited classes and this instance initialise
 132 successfully.  */
 133     virtual bool init(OSObject *owner,
 134                       Action action,
 135                       IOService *provider = 0,
 136                       int intIndex = 0);
 137
 138 /*! @function enable
 139     @abstract Enable event source.
 140     @discussion A subclass implementation is expected to respect the enabled
 141 state when checkForWork is called.  Calling this function will cause the
 142 work-loop to be signalled so that a checkForWork is performed. */
 143     virtual void enable();
 144
 145 /*! @function disable
 146     @abstract Disable event source.
 147     @discussion A subclass implementation is expected to respect the enabled
 148 state when checkForWork is called. */
 149     virtual void disable();
 150
 151 /*! @function getProvider
 152     @abstract Get'ter for $link provider variable.
 153     @result value of provider. */
 154     virtual const IOService *getProvider() const;
 155
 156 /*! @function getIntIndex
 157     @abstract Get'ter for $link intIndex interrupt index variable.
 158     @result value of intIndex. */
 159     virtual int getIntIndex() const;
 160
 161 /*! @function getAutoDisable
 162     @abstract Get'ter for $link autoDisable variable.
 163     @result value of autoDisable. */
 164     virtual bool getAutoDisable() const;
 165
 166 /*! @function interruptOccurred
 167     @abstract Functions that get called by the interrupt controller. See $link IOService::registerInterrupt
 168     @param nub Where did the interrupt originate from
 169     @param ind What is this interrupts index within 'nub'. */
 170     virtual void interruptOccurred(void *, IOService *nub, int ind);
 171
 172 /*! @function normalInterruptOccurred
 173     @abstract Functions that get called by the interrupt controller.See $link IOService::registerInterrupt
 174     @param nub Where did the interrupt originate from
 175     @param ind What is this interrupts index within 'nub'. */
 176     virtual void normalInterruptOccurred(void *, IOService *nub, int ind);
 177
 178 /*! @function disableInterruptOccurred
 179     @abstract Functions that get called by the interrupt controller.See $link IOService::registerInterrupt
 180     @param nub Where did the interrupt originate from
 181     @param ind What is this interrupts index within 'nub'. */
 182     virtual void disableInterruptOccurred(void *, IOService *nub, int ind);
 183
 184 private:
 185     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 0);
 186     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 1);
 187     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 2);
 188     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 3);
 189     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 4);
 190     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 5);
 191     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 6);
 192     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 7);
 193 };
 194
 195 #endif /* !_IOKIT_IOINTERRUPTEVENTSOURCE_H */