iokit/IOKit/IOTimerEventSource.h

   1 /*
   2  * Copyright (c) 1998-2000, 2009 Apple Inc. All rights reserved.
   3  *
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   8  * Version 2.0 (the 'License'). You may not use this file except in
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  10  * may not be used to create, or enable the creation or redistribution of,
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  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
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  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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  23  * Please see the License for the specific language governing rights and
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  27  */
  28 /*
  29  * Copyright (c) 1999 Apple Computer, Inc.  All rights reserved.
  30  *
  31  * IOTimerEventSource.h
  32  *
  33  * HISTORY
  34  * 2-Feb-1999           Joe Liu (jliu) created.
  35  *
  36  */
  37
  38 #ifndef _IOTIMEREVENTSOURCE
  39 #define _IOTIMEREVENTSOURCE
  40
  41 #include <sys/cdefs.h>
  42
  43 __BEGIN_DECLS
  44 #include <kern/clock.h>
  45 __END_DECLS
  46
  47 #include <IOKit/IOEventSource.h>
  48 #include <IOKit/IOTypes.h>
  49
  50 /*!
  51     @class IOTimerEventSource : public IOEventSource
  52     @abstract Time based event source mechanism.
  53     @discussion An event source that implements a simple timer.  A timeout handler is called once the timeout period expires.  This timeout handler will be called by the work-loop that this event source is attached to.
  54 <br><br>
  55         Usually a timer event source will be used to implement a timeout.  In general when a driver makes a request it will need to setup a call to keep track of when the I/O doesn't complete.  This class is designed to make that somewhat easier.
  56 <br><br>
  57         Remember the system doesn't guarantee the accuracy of the callout.      It is possible that a higher priority thread is running which will delay the execution of the action routine.  In fact the thread will be made runable at the exact requested time, within the accuracy of the CPU's decrementer based interrupt, but the scheduler will then control execution.
  58 */
  59 class IOTimerEventSource : public IOEventSource
  60 {
  61     OSDeclareDefaultStructors(IOTimerEventSource)
  62
  63 protected:
  64 /*! @var calloutEntry thread_call entry for preregistered thread callouts */
  65     void *calloutEntry;
  66
  67 /*! @var abstime time to wake up next, see enable. */
  68     AbsoluteTime abstime;
  69
  70 /*! @struct ExpansionData
  71     @discussion This structure is private to the IOTimerEventSource implementation.
  72     */
  73     struct ExpansionData
  74     {
  75         SInt32       calloutGeneration;
  76         IOWorkLoop * workLoop;
  77     };
  78
  79 /*! @var reserved
  80     Reserved for future use.  (Internal use only)  */
  81     ExpansionData *reserved;
  82
  83 /*! @function timeout
  84     @abstract Function that routes the call from the OS' timeout mechanism into a work-loop context.
  85     @discussion timeout will normally not be called nor overridden by a subclass.  If the event source is enabled then close the work-loop's gate and call the action routine.
  86     @param self This argument will be cast to an IOTimerEventSource. */
  87     static void timeout(void *self);
  88
  89 /*! @function setTimeoutFunc
  90     @abstract Set's timeout as the function of calloutEntry.
  91     @discussion IOTimerEventSource is based upon the kern/thread_call.h APIs currently.  This function allocates the calloutEntry member variable by using thread_call_allocate(timeout, this).  If you need to write your own subclass of IOTimerEventSource you probably should override this method to allocate an entry that points to your own timeout routine. */
  92     virtual void setTimeoutFunc();
  93
  94 /*! @function free
  95     @abstract Sub-class implementation of free method, frees calloutEntry */
  96     virtual void free();
  97
  98     virtual void setWorkLoop(IOWorkLoop *workLoop);
  99
 100 public:
 101
 102 /*! @typedef Action
 103     @discussion 'C' Function pointer defining the callout routine of this event source.
 104     @param owner Owning target object.  Note by a startling coincidence the first parameter in a C callout is currently used to define the target of a C++ member function.
 105     @param sender The object that timed out. */
 106     typedef void (*Action)(OSObject *owner, IOTimerEventSource *sender);
 107
 108 /*! @function timerEventSource
 109     @abstract Allocates and returns an initialized timer instance.
 110     @param owner
 111     @param action */
 112     static IOTimerEventSource *
 113         timerEventSource(OSObject *owner, Action action = 0);
 114
 115 /*! @function init
 116     @abstract Initializes the timer with an owner, and a handler to call when the timeout expires.
 117     @param owner
 118     @param action */
 119     virtual bool init(OSObject *owner, Action action = 0);
 120
 121 /*! @function enable
 122     @abstract Enables a call to the action.
 123     @discussion Allows the action function to be called.  If the timer event source was disabled while a call was outstanding and the call wasn't cancelled then it will be rescheduled.  So a disable/enable pair will disable calls from this event source. */
 124     virtual void enable();
 125
 126 /*! @function disable
 127     @abstract Disable a timed callout.
 128     @discussion When disable returns the action will not be called until the next time enable(qv) is called. */
 129     virtual void disable();
 130
 131
 132 /*! @function setTimeoutTicks
 133     @abstract Setup a callback at after the delay in scheduler ticks.  See wakeAtTime(AbsoluteTime).
 134     @param interval Delay from now to wake up, in scheduler ticks, whatever that may be.
 135     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 136     virtual IOReturn setTimeoutTicks(UInt32 ticks);
 137
 138 /*! @function setTimeoutMS
 139     @abstract Setup a callback at after the delay in milliseconds.  See wakeAtTime(AbsoluteTime).
 140     @param interval Delay from now to wake up, time in milliseconds.
 141     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 142     virtual IOReturn setTimeoutMS(UInt32 ms);
 143
 144 /*! @function setTimeoutUS
 145         @abstract Setup a callback at after the delay in microseconds.   See wakeAtTime(AbsoluteTime).
 146     @param interval Delay from now to wake up, time in microseconds.
 147     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 148     virtual IOReturn setTimeoutUS(UInt32 us);
 149
 150 /*! @function setTimeout
 151     @abstract Setup a callback at after the delay in some unit.  See wakeAtTime(AbsoluteTime).
 152     @param interval Delay from now to wake up in some defined unit.
 153     @param scale_factor Define the unit of interval, default to nanoseconds.
 154     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 155     virtual IOReturn setTimeout(UInt32 interval,
 156                                 UInt32 scale_factor = kNanosecondScale);
 157
 158 #if !defined(__LP64__)
 159     virtual IOReturn setTimeout(mach_timespec_t interval)
 160         APPLE_KEXT_DEPRECATED;
 161 #endif
 162
 163 /*! @function setTimeout
 164     @abstract Setup a callback at after the delay in decrementer ticks.  See wakeAtTime(AbsoluteTime).
 165     @param interval Delay from now to wake up in decrementer ticks.
 166     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 167     virtual IOReturn setTimeout(AbsoluteTime interval);
 168
 169 /*! @function wakeAtTimeTicks
 170     @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
 171     @param abstime Time to wake up in scheduler quantums, whatever that is?
 172     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 173     virtual IOReturn wakeAtTimeTicks(UInt32 ticks);
 174
 175 /*! @function wakeAtTimeMS
 176     @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
 177     @param abstime Time to wake up in milliseconds.
 178     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 179     virtual IOReturn wakeAtTimeMS(UInt32 ms);
 180
 181 /*! @function wakeAtTimeUS
 182     @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
 183     @param abstime Time to wake up in microseconds.
 184     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 185     virtual IOReturn wakeAtTimeUS(UInt32 us);
 186
 187 /*! @function wakeAtTime
 188     @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
 189     @param abstime Time to wake up in some unit.
 190     @param scale_factor Define the unit of abstime, default to nanoseconds.
 191     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 192     virtual IOReturn wakeAtTime(UInt32 abstime,
 193                                 UInt32 scale_factor = kNanosecondScale);
 194
 195 #if !defined(__LP64__)
 196     virtual IOReturn wakeAtTime(mach_timespec_t abstime)
 197         APPLE_KEXT_DEPRECATED;
 198 #endif
 199
 200 /*! @function wakeAtTime
 201     @abstract Setup a callback at this absolute time.
 202     @discussion Starts the timer, which will expire at abstime. After it expires, the timer will call the 'action' registered in the init() function. This timer is not periodic, a further call is needed to reset and restart the timer after it expires.
 203     @param abstime Absolute Time when to wake up, counted in 'decrementer' units and starts at zero when system boots.
 204     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared by init or IOEventSource::setAction (qqv). */
 205     virtual IOReturn wakeAtTime(AbsoluteTime abstime);
 206
 207 /*! @function cancelTimeout
 208     @abstract Disable any outstanding calls to this event source.
 209     @discussion Clear down any oustanding calls.  By the time this function completes it is guaranteed that the action will not be called again. */
 210    virtual void cancelTimeout();
 211
 212 private:
 213     static void timeoutAndRelease(void *self, void *wl);
 214
 215 private:
 216     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 0);
 217     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 1);
 218     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 2);
 219     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 3);
 220     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 4);
 221     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 5);
 222     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 6);
 223     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 7);
 224 };
 225
 226 #endif /* !_IOTIMEREVENTSOURCE */