iokit/IOKit/IOTimerEventSource.h

   1 /*
   2  * Copyright (c) 1998-2016 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_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. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  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
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  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         @enum IOTimerEventSource constructor options
  52         @abstract Constants defining behavior of the IOTimerEventSource.
  53         @constant kIOTimerEventSourceOptionsPriorityHigh Importance above everything but realtime.
  54         Thread calls allocated with this priority execute at extremely high priority,
  55         above everything but realtime threads.  They are generally executed in serial.
  56         Though they may execute concurrently under some circumstances, no fan-out is implied.
  57         These work items should do very small amounts of work or risk disrupting system
  58         responsiveness.
  59         @constant kIOTimerEventSourceOptionsPriorityKernelHigh Importance higher than most kernel
  60         threads.
  61         @constant kIOTimerEventSourceOptionsPriorityKernel Importance similar to that of normal kernel
  62         threads.
  63         @constant kIOTimerEventSourceOptionsPriorityUser Importance similar to that of normal user threads.
  64         @constant kIOTimerEventSourceOptionsPriorityLow Very low importance.
  65         @constant kIOTimerEventSourceOptionsPriorityWorkLoop Run the callout on the thread of the IOWorkLoop
  66         the event source has been added to.
  67         @constant kIOTimerEventSourceOptionsAllowReenter Allow the callout to be rescheduled and potentially
  68         re-entered, if the IOWorkLoop lock has been released (eg. with commandSleep) during its invocation.
  69         @constant kIOTimerEventSourceOptionsDefault Recommended default options.
  70  */
  71 enum
  72 {
  73     kIOTimerEventSourceOptionsPriorityMask       = 0x000000ff,
  74     kIOTimerEventSourceOptionsPriorityHigh       = 0x00000000,
  75     kIOTimerEventSourceOptionsPriorityKernelHigh = 0x00000001,
  76     kIOTimerEventSourceOptionsPriorityKernel     = 0x00000002,
  77     kIOTimerEventSourceOptionsPriorityUser       = 0x00000003,
  78     kIOTimerEventSourceOptionsPriorityLow        = 0x00000004,
  79     kIOTimerEventSourceOptionsPriorityWorkLoop   = 0x000000ff,
  80
  81     kIOTimerEventSourceOptionsAllowReenter       = 0x00000100,
  82
  83     kIOTimerEventSourceOptionsDefault            = kIOTimerEventSourceOptionsPriorityKernelHigh
  84 };
  85
  86 #define IOTIMEREVENTSOURCEOPTIONS_DEFINED       1
  87
  88 /*!
  89         @enum IOTimerEventSource setTimeout/wakeAtTime options
  90         @abstract Constants defining behavior of a scheduled call from IOTimerEventSource.
  91         @constant kIOTimeOptionsWithLeeway Use the leeway parameter to the call.
  92         @constant kIOTimeOptionsContinuous Use mach_continuous_time() to generate the callback.
  93 */
  94 enum
  95 {
  96     kIOTimeOptionsWithLeeway = 0x00000020,
  97     kIOTimeOptionsContinuous = 0x00000100,
  98 };
  99
 100 /*!
 101     @class IOTimerEventSource : public IOEventSource
 102     @abstract Time based event source mechanism.
 103     @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.
 104 <br><br>
 105         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.
 106 <br><br>
 107         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.
 108 */
 109
 110 class IOTimerEventSource : public IOEventSource
 111 {
 112     OSDeclareDefaultStructors(IOTimerEventSource)
 113
 114 protected:
 115 /*! @var calloutEntry thread_call entry for preregistered thread callouts */
 116     void *calloutEntry;
 117
 118 /*! @var abstime time to wake up next, see enable. */
 119     AbsoluteTime abstime;
 120
 121 /*! @struct ExpansionData
 122     @discussion This structure is private to the IOTimerEventSource implementation.
 123     */
 124     struct ExpansionData
 125     {
 126         SInt32       calloutGeneration;
 127         SInt32       calloutGenerationSignaled;
 128         IOWorkLoop * workLoop;
 129     };
 130
 131 /*! @var reserved
 132     Reserved for future use.  (Internal use only)  */
 133     APPLE_KEXT_WSHADOW_PUSH;
 134     ExpansionData *reserved;
 135     APPLE_KEXT_WSHADOW_POP;
 136
 137 /*! @function timeout
 138     @abstract Function that routes the call from the OS' timeout mechanism into a work-loop context.
 139     @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.
 140     @param self This argument will be cast to an IOTimerEventSource. */
 141     static void timeout(void *self);
 142
 143 /*! @function setTimeoutFunc
 144     @abstract Set's timeout as the function of calloutEntry.
 145     @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. */
 146     virtual void setTimeoutFunc();
 147
 148 /*! @function free
 149     @abstract Sub-class implementation of free method, frees calloutEntry */
 150     virtual void free() APPLE_KEXT_OVERRIDE;
 151
 152     virtual void setWorkLoop(IOWorkLoop *workLoop) APPLE_KEXT_OVERRIDE;
 153
 154 public:
 155
 156 /*! @typedef Action
 157     @discussion 'C' Function pointer defining the callout routine of this event source.
 158     @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.
 159     @param sender The object that timed out. */
 160     typedef void (*Action)(OSObject *owner, IOTimerEventSource *sender);
 161
 162     static IOTimerEventSource *
 163         timerEventSource(OSObject *owner, Action action = 0);
 164
 165 /*! @function timerEventSource
 166     @abstract Allocates and returns an initialized timer instance.
 167     @param options Mask of kIOTimerEventSourceOptions* options.
 168     @param owner The object that that will be passed to the Action callback.
 169     @param action 'C' Function pointer for the callout routine of this event source.
 170     */
 171     static IOTimerEventSource *
 172         timerEventSource(uint32_t options, OSObject *owner, Action action = 0);
 173
 174 /*! @function init
 175     @abstract Initializes the timer with an owner, and a handler to call when the timeout expires.
 176     */
 177     virtual bool init(OSObject *owner, Action action = 0);
 178
 179 /*! @function enable
 180     @abstract Enables a call to the action.
 181     @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. */
 182     virtual void enable() APPLE_KEXT_OVERRIDE;
 183
 184 /*! @function disable
 185     @abstract Disable a timed callout.
 186     @discussion When disable returns the action will not be called until the next time enable(qv) is called. */
 187     virtual void disable() APPLE_KEXT_OVERRIDE;
 188
 189 /*! @function checkForWork
 190     @abstract Pure Virtual member function used by IOWorkLoop for issuing a client calls.
 191     @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.
 192     @result Return true if this function needs to be called again before all its outstanding events have been processed. */
 193     virtual bool checkForWork() APPLE_KEXT_OVERRIDE;
 194
 195 /*! @function setTimeoutTicks
 196     @abstract Setup a callback at after the delay in scheduler ticks.  See wakeAtTime(AbsoluteTime).
 197     @param ticks Delay from now to wake up, in scheduler ticks, whatever that may be.
 198     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 199     virtual IOReturn setTimeoutTicks(UInt32 ticks);
 200
 201 /*! @function setTimeoutMS
 202     @abstract Setup a callback at after the delay in milliseconds.  See wakeAtTime(AbsoluteTime).
 203     @param ms Delay from now to wake up, time in milliseconds.
 204     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 205     virtual IOReturn setTimeoutMS(UInt32 ms);
 206
 207 /*! @function setTimeoutUS
 208         @abstract Setup a callback at after the delay in microseconds.   See wakeAtTime(AbsoluteTime).
 209     @param us Delay from now to wake up, time in microseconds.
 210     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 211     virtual IOReturn setTimeoutUS(UInt32 us);
 212
 213 /*! @function setTimeout
 214     @abstract Setup a callback at after the delay in some unit.  See wakeAtTime(AbsoluteTime).
 215     @param interval Delay from now to wake up in some defined unit.
 216     @param scale_factor Define the unit of interval, default to nanoseconds.
 217     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 218     virtual IOReturn setTimeout(UInt32 interval,
 219                                 UInt32 scale_factor = kNanosecondScale);
 220
 221 #if !defined(__LP64__)
 222     virtual IOReturn setTimeout(mach_timespec_t interval)
 223         APPLE_KEXT_DEPRECATED;
 224 #endif
 225
 226 /*! @function setTimeout
 227     @abstract Setup a callback at after the delay in decrementer ticks.  See wakeAtTime(AbsoluteTime).
 228     @param interval Delay from now to wake up in decrementer ticks.
 229     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 230     virtual IOReturn setTimeout(AbsoluteTime interval);
 231
 232 /*! @function wakeAtTimeTicks
 233     @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
 234     @param ticks Time to wake up in scheduler quantums, whatever that is?
 235     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 236     virtual IOReturn wakeAtTimeTicks(UInt32 ticks);
 237
 238 /*! @function wakeAtTimeMS
 239     @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
 240     @param ms Time to wake up in milliseconds.
 241     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 242     virtual IOReturn wakeAtTimeMS(UInt32 ms);
 243
 244 /*! @function wakeAtTimeUS
 245     @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
 246     @param us Time to wake up in microseconds.
 247     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 248     virtual IOReturn wakeAtTimeUS(UInt32 us);
 249
 250 /*! @function wakeAtTime
 251     @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
 252     @param abstime Time to wake up in some unit.
 253     @param scale_factor Define the unit of abstime, default to nanoseconds.
 254     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 255     virtual IOReturn wakeAtTime(UInt32 abstime,
 256                                 UInt32 scale_factor = kNanosecondScale);
 257
 258 #if !defined(__LP64__)
 259     virtual IOReturn wakeAtTime(mach_timespec_t abstime)
 260         APPLE_KEXT_DEPRECATED;
 261 #endif
 262
 263 /*! @function wakeAtTime
 264     @abstract Setup a callback at this absolute time.
 265     @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.
 266     @param abstime Absolute Time when to wake up, counted in 'decrementer' units and starts at zero when system boots.
 267     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared by init or IOEventSource::setAction (qqv). */
 268     virtual IOReturn wakeAtTime(AbsoluteTime abstime);
 269
 270 /*! @function cancelTimeout
 271     @abstract Disable any outstanding calls to this event source.
 272     @discussion Clear down any oustanding calls.  By the time this function completes it is guaranteed that the action will not be called again. */
 273    virtual void cancelTimeout();
 274
 275 /*! @function init
 276     @abstract Initializes the timer with an owner, and a handler to call when the timeout expires.
 277     */
 278     virtual bool init(uint32_t options, OSObject *inOwner, Action inAction);
 279
 280 /*! @function setTimeout
 281     @abstract Setup a callback at after the delay in decrementer ticks.  See wakeAtTime(AbsoluteTime).
 282     @param options see kIOTimeOptionsWithLeeway and kIOTimeOptionsContinuous
 283     @param interval Delay from now to wake up in decrementer ticks.
 284     @param leeway Allowable leeway to wake time, if the kIOTimeOptionsWithLeeway option is set
 285     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
 286     virtual IOReturn setTimeout(uint32_t options, AbsoluteTime interval, AbsoluteTime leeway);
 287
 288 /*! @function wakeAtTime
 289     @abstract Setup a callback at this absolute time.
 290     @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.
 291     @param options see kIOTimeOptionsWithLeeway and kIOTimeOptionsContinuous
 292     @param abstime Absolute Time when to wake up, counted in 'decrementer' units and starts at zero when system boots.
 293     @param leeway Allowable leeway to wake time, if the kIOTimeOptionsWithLeeway option is set
 294     @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared by init or IOEventSource::setAction (qqv). */
 295     virtual IOReturn wakeAtTime(uint32_t options, AbsoluteTime abstime, AbsoluteTime leeway);
 296
 297 private:
 298     static void timeoutAndRelease(void *self, void *c);
 299     static void timeoutSignaled(void *self, void *c);
 300
 301 private:
 302     OSMetaClassDeclareReservedUsed(IOTimerEventSource, 0);
 303     OSMetaClassDeclareReservedUsed(IOTimerEventSource, 1);
 304     OSMetaClassDeclareReservedUsed(IOTimerEventSource, 2);
 305     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 3);
 306     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 4);
 307     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 5);
 308     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 6);
 309     OSMetaClassDeclareReservedUnused(IOTimerEventSource, 7);
 310 };
 311
 312 #endif /* !_IOTIMEREVENTSOURCE */