1/*
2 * Copyright (c) 1998-2000 Apple Computer, 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
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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    @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*/
59class IOTimerEventSource : public IOEventSource
60{
61    OSDeclareDefaultStructors(IOTimerEventSource)
62
63protected:
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/*! @function checkForWork
99    @abstract Have to implement it is mandatory in $link IOEventSource, but IOTimerEventSources don't actually use this work-loop mechanism. */
100    virtual bool checkForWork();
101
102    virtual void setWorkLoop(IOWorkLoop *workLoop);
103
104public:
105
106/*! @typedef Action
107    @discussion 'C' Function pointer defining the callout routine of this event source.
108    @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.
109    @param sender The object that timed out. */
110    typedef void (*Action)(OSObject *owner, IOTimerEventSource *sender);
111
112/*! @function timerEventSource
113    @abstract Allocates and returns an initialized timer instance.
114    @param owner
115    @param action */
116    static IOTimerEventSource *
117	timerEventSource(OSObject *owner, Action action = 0);
118
119/*! @function init
120    @abstract Initializes the timer with an owner, and a handler to call when the timeout expires.
121    @param owner
122    @param action */
123    virtual bool init(OSObject *owner, Action action = 0);
124
125/*! @function enable
126    @abstract Enables a call to the action.
127    @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. */
128    virtual void enable();
129
130/*! @function disable
131    @abstract Disable a timed callout.
132    @discussion When disable returns the action will not be called until the next time enable(qv) is called. */
133    virtual void disable();
134
135
136/*! @function setTimeoutTicks
137    @abstract Setup a callback at after the delay in scheduler ticks.  See wakeAtTime(AbsoluteTime).
138    @param interval Delay from now to wake up, in scheduler ticks, whatever that may be.
139    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
140    virtual IOReturn setTimeoutTicks(UInt32 ticks);
141
142/*! @function setTimeoutMS
143    @abstract Setup a callback at after the delay in milliseconds.  See wakeAtTime(AbsoluteTime).
144    @param interval Delay from now to wake up, time in milliseconds.
145    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
146    virtual IOReturn setTimeoutMS(UInt32 ms);
147
148/*! @function setTimeoutUS
149        @abstract Setup a callback at after the delay in microseconds.	 See wakeAtTime(AbsoluteTime).
150    @param interval Delay from now to wake up, time in microseconds.
151    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
152    virtual IOReturn setTimeoutUS(UInt32 us);
153
154/*! @function setTimeout
155    @abstract Setup a callback at after the delay in some unit.	 See wakeAtTime(AbsoluteTime).
156    @param interval Delay from now to wake up in some defined unit.
157    @param scale_factor Define the unit of interval, default to nanoseconds.
158    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
159    virtual IOReturn setTimeout(UInt32 interval,
160				UInt32 scale_factor = kNanosecondScale);
161
162/*! @function setTimeout
163    @abstract Setup a callback at after the delay in decrementer ticks.	 See wakeAtTime(AbsoluteTime).
164    @param interval Delay from now to wake up.
165    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
166    virtual IOReturn setTimeout(mach_timespec_t interval);
167
168/*! @function setTimeout
169    @abstract Setup a callback at after the delay in decrementer ticks.	 See wakeAtTime(AbsoluteTime).
170    @param interval Delay from now to wake up in decrementer ticks.
171    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
172    virtual IOReturn setTimeout(AbsoluteTime interval);
173
174/*! @function wakeAtTimeTicks
175    @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
176    @param abstime Time to wake up in scheduler quantums, whatever that is?
177    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
178    virtual IOReturn wakeAtTimeTicks(UInt32 ticks);
179
180/*! @function wakeAtTimeMS
181    @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
182    @param abstime Time to wake up in milliseconds.
183    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
184    virtual IOReturn wakeAtTimeMS(UInt32 ms);
185
186/*! @function wakeAtTimeUS
187    @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
188    @param abstime Time to wake up in microseconds.
189    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
190    virtual IOReturn wakeAtTimeUS(UInt32 us);
191
192/*! @function wakeAtTime
193    @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
194    @param abstime Time to wake up in some unit.
195    @param scale_factor Define the unit of abstime, default to nanoseconds.
196    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
197    virtual IOReturn wakeAtTime(UInt32 abstime,
198				UInt32 scale_factor = kNanosecondScale);
199
200/*! @function wakeAtTime
201    @abstract Setup a callback at this absolute time.  See wakeAtTime(AbsoluteTime).
202    @param abstime mach_timespec_t of the desired callout time.
203    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared. */
204    virtual IOReturn wakeAtTime(mach_timespec_t abstime);
205
206/*! @function wakeAtTime
207    @abstract Setup a callback at this absolute time.
208    @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.
209    @param abstime Absolute Time when to wake up, counted in 'decrementer' units and starts at zero when system boots.
210    @result kIOReturnSuccess if everything is fine, kIOReturnNoResources if action hasn't been declared by init or IOEventSource::setAction (qqv). */
211    virtual IOReturn wakeAtTime(AbsoluteTime abstime);
212
213/*! @function cancelTimeout
214    @abstract Disable any outstanding calls to this event source.
215    @discussion Clear down any oustanding calls.  By the time this function completes it is guaranteed that the action will not be called again. */
216   virtual void cancelTimeout();
217
218private:
219    static void timeoutAndRelease(void *self, void *wl);
220
221private:
222    OSMetaClassDeclareReservedUnused(IOTimerEventSource, 0);
223    OSMetaClassDeclareReservedUnused(IOTimerEventSource, 1);
224    OSMetaClassDeclareReservedUnused(IOTimerEventSource, 2);
225    OSMetaClassDeclareReservedUnused(IOTimerEventSource, 3);
226    OSMetaClassDeclareReservedUnused(IOTimerEventSource, 4);
227    OSMetaClassDeclareReservedUnused(IOTimerEventSource, 5);
228    OSMetaClassDeclareReservedUnused(IOTimerEventSource, 6);
229    OSMetaClassDeclareReservedUnused(IOTimerEventSource, 7);
230};
231
232#endif /* !_IOTIMEREVENTSOURCE */
233