iokit/IOKit/IOInterruptEventSource.h

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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 struct IOInterruptAccountingData;
  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         IOInterruptAccountingData * statistics;
 103     };
 104
 105 /*! @var reserved
 106     Reserved for future use.  (Internal use only)  */
 107     ExpansionData *reserved;
 108
 109 /*! @function free
 110     @abstract Sub-class implementation of free method, disconnects from the interrupt source. */
 111     virtual void free();
 112
 113 /*! @function checkForWork
 114     @abstract Pure Virtual member function used by IOWorkLoop for issueing a client calls.
 115     @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.
 116     @result Return true if this function needs to be called again before all its outstanding events have been processed. */
 117     virtual bool checkForWork();
 118
 119 /*! @function setWorkLoop
 120     @abstract Sub-class implementation of setWorkLoop method. */
 121     virtual void setWorkLoop(IOWorkLoop *inWorkLoop);
 122
 123 public:
 124
 125 /*! @function interruptEventSource
 126     @abstract Factory function for IOInterruptEventSources creation and initialisation.
 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 A new interrupt event source if successfully created and initialised, 0 otherwise.  */
 132     static IOInterruptEventSource *
 133         interruptEventSource(OSObject *owner,
 134                              Action action,
 135                              IOService *provider = 0,
 136                              int intIndex = 0);
 137
 138 /*! @function init
 139     @abstract Primary initialiser for the IOInterruptEventSource class.
 140     @param owner Owning client of the new event source.
 141     @param action 'C' Function to call when something happens.
 142     @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.
 143     @param intIndex The index of the interrupt within the provider's interrupt sources.  Defaults to 0, i.e. the first interrupt in the provider.
 144     @result true if the inherited classes and this instance initialise
 145 successfully.  */
 146     virtual bool init(OSObject *owner,
 147                       Action action,
 148                       IOService *provider = 0,
 149                       int intIndex = 0);
 150
 151 /*! @function enable
 152     @abstract Enable event source.
 153     @discussion A subclass implementation is expected to respect the enabled
 154 state when checkForWork is called.  Calling this function will cause the
 155 work-loop to be signalled so that a checkForWork is performed. */
 156     virtual void enable();
 157
 158 /*! @function disable
 159     @abstract Disable event source.
 160     @discussion A subclass implementation is expected to respect the enabled
 161 state when checkForWork is called. */
 162     virtual void disable();
 163
 164 /*! @function getProvider
 165     @abstract Get'ter for $link provider variable.
 166     @result value of provider. */
 167     virtual const IOService *getProvider() const;
 168
 169 /*! @function getIntIndex
 170     @abstract Get'ter for $link intIndex interrupt index variable.
 171     @result value of intIndex. */
 172     virtual int getIntIndex() const;
 173
 174 /*! @function getAutoDisable
 175     @abstract Get'ter for $link autoDisable variable.
 176     @result value of autoDisable. */
 177     virtual bool getAutoDisable() const;
 178
 179 /*! @function interruptOccurred
 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 interruptOccurred(void *, IOService *nub, int ind);
 184
 185 /*! @function normalInterruptOccurred
 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 normalInterruptOccurred(void *, IOService *nub, int ind);
 190
 191 /*! @function disableInterruptOccurred
 192     @abstract Functions that get called by the interrupt controller.See $link IOService::registerInterrupt
 193     @param nub Where did the interrupt originate from
 194     @param ind What is this interrupts index within 'nub'. */
 195     virtual void disableInterruptOccurred(void *, IOService *nub, int ind);
 196
 197 /*! @function warmCPU
 198     @abstract Tries to reduce latency for an interrupt which will be received near a specified time.
 199     @discussion Warms up a CPU in advance of an interrupt so that the interrupt may be serviced with predictable latency.
 200     The warm-up is not periodic; callers should call warmCPU once in advance of each interrupt.  It is recommended that
 201     requests be issues in serial (i.e. each after the target for the previous call has elapsed), as there is a systemwide
 202     cap on the number of outstanding requests.  This routine may be disruptive to the system if used with very small intervals
 203     between requests; it should be used only in cases where interrupt latency is absolutely critical, and tens or hundreds of
 204     milliseconds between targets is the expected time scale.  NOTE: it is not safe to call this method with interrupts disabled.
 205     @param abstime Time at which interrupt is expected. */
 206     IOReturn warmCPU(uint64_t abstime);
 207
 208 private:
 209     IOReturn registerInterruptHandler(IOService *inProvider, int inIntIndex);
 210     void unregisterInterruptHandler(IOService *inProvider, int inIntIndex);
 211
 212 private:
 213     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 0);
 214     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 1);
 215     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 2);
 216     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 3);
 217     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 4);
 218     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 5);
 219     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 6);
 220     OSMetaClassDeclareReservedUnused(IOInterruptEventSource, 7);
 221 };
 222
 223 #endif /* !_IOKIT_IOINTERRUPTEVENTSOURCE_H */