xnu-2782.10.72.tar.gz

[apple/xnu.git] / iokit / IOKit / IOWorkLoop.h

diff --git a/iokit/IOKit/IOWorkLoop.h b/iokit/IOKit/IOWorkLoop.h
index eba08bbcb096466e0bfded6aaa4def5530bc8aa2..e248a9b3bd7cabf0fb78de278045c88f1c556d2f 100644 (file)
--- a/iokit/IOKit/IOWorkLoop.h
+++ b/iokit/IOKit/IOWorkLoop.h
@@ -1,5 +1,5 @@
 /*
 /*

- * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1998-2009 Apple Inc. All rights reserved.

  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 


@@ -25,14 +25,6 @@
  * 
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
  * 
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */

-/*
-Copyright (c) 1998 Apple Computer, Inc.         All rights reserved.
-HISTORY
-    1998-7-13  Godfrey van der Linden(gvdl)
-       Created.
-    1998-10-30 Godfrey van der Linden(gvdl)
-       Converted to C++
-*/

 
 #ifndef __IOKIT_IOWORKLOOP_H
 #define __IOKIT_IOWORKLOOP_H
 
 #ifndef __IOKIT_IOWORKLOOP_H
 #define __IOKIT_IOWORKLOOP_H


@@ -44,6 +36,10 @@ HISTORY
 
 #include <IOKit/system.h>
 
 
 #include <IOKit/system.h>
 

+#if IOKITSTATS
+#include <IOKit/IOStatisticsPrivate.h>
+#endif
+

 class IOEventSource;
 class IOTimerEventSource;
 class IOCommandGate;
 class IOEventSource;
 class IOTimerEventSource;
 class IOCommandGate;


@@ -78,13 +74,23 @@ member function's parameter list.
     typedef IOReturn (*Action)(OSObject *target,
                               void *arg0, void *arg1,
                               void *arg2, void *arg3);
     typedef IOReturn (*Action)(OSObject *target,
                               void *arg0, void *arg1,
                               void *arg2, void *arg3);

+    enum {
+       kPreciousStack = 0x00000001
+    };

 
 private:
 /*! @function threadMainContinuation
     @abstract Static function that calls the threadMain function. 
 */
     static void threadMainContinuation(IOWorkLoop *self);
 
 private:
 /*! @function threadMainContinuation
     @abstract Static function that calls the threadMain function. 
 */
     static void threadMainContinuation(IOWorkLoop *self);

-
+       
+/*! @function eventSourcePerformsWork
+       @abstract Checks if the event source passed in overrides checkForWork() to perform any work.
+IOWorkLoop uses this to determine if the event source should be polled in runEventSources() or not.
+       @param inEventSource The event source to check.
+*/
+       bool eventSourcePerformsWork(IOEventSource *inEventSource);
+       

 protected:
 
 /*! @typedef maintCommandEnum
 protected:
 
 /*! @typedef maintCommandEnum


@@ -96,6 +102,7 @@ protected:
 
 /*! @var gateLock
     Mutual exclusion lock that is used by close and open Gate functions.  
 
 /*! @var gateLock
     Mutual exclusion lock that is used by close and open Gate functions.  

+    This is a recursive lock, which allows multiple layers of code to share a single IOWorkLoop without deadlock.  This is common in IOKit since threads of execution tend to follow the service plane in the IORegistry, and multiple objects along the call path may acquire the gate for the same (shared) workloop.

 */
     IORecursiveLock *gateLock;
 
 */
     IORecursiveLock *gateLock;
 


@@ -109,7 +116,7 @@ protected:
 */
     IOCommandGate *controlG;
 
 */
     IOCommandGate *controlG;
 

-/*! @var workSpinLock
+/*! @var workToDoLock

     The spin lock that is used to guard the 'workToDo' variable. 
 */
     IOSimpleLock *workToDoLock;
     The spin lock that is used to guard the 'workToDo' variable. 
 */
     IOSimpleLock *workToDoLock;


@@ -132,7 +139,18 @@ protected:
 /*! @struct ExpansionData
     @discussion This structure will be used to expand the capablilties of the IOWorkLoop in the future.
 */    
 /*! @struct ExpansionData
     @discussion This structure will be used to expand the capablilties of the IOWorkLoop in the future.
 */    

-    struct ExpansionData { };
+    struct ExpansionData {
+       IOOptionBits options;
+       IOEventSource *passiveEventChain;
+#if DEBUG
+       void * allocationBacktrace[16];
+#endif /* DEBUG */
+#if IOKITSTATS
+       struct IOWorkLoopCounter *counter;
+#else
+       void *iokitstatsReserved;
+#endif
+    };

 
 /*! @var reserved
     Reserved for future use.  (Internal use only) 
 
 /*! @var reserved
     Reserved for future use.  (Internal use only) 


@@ -154,20 +172,33 @@ protected:
     virtual void free();
 
 /*! @function threadMain
     virtual void free();
 
 /*! @function threadMain

-    @discussion Work loop threads main function.  This function consists of 3 loops: the outermost loop is the semaphore clear and wait loop, the middle loop terminates when there is no more work, and the inside loop walks the event list calling the checkForWork method in each event source.  If an event source has more work to do, it can set the more flag and the middle loop will repeat.  When no more work is outstanding the outermost will sleep until an event is signalled or the least wakeupTime, whichever occurs first.  If the event source does not require the semaphore wait to time out, it must set the provided wakeupTime parameter to zero.
+    @discussion Work loop threads main function.  This function consists of 3
+    loops: the outermost loop is the semaphore clear and wait loop, the middle
+    loop terminates when there is no more work, and the inside loop walks the
+    event list calling the checkForWork method in each event source.  If an
+    event source has more work to do, it can set the more flag and the middle
+    loop will repeat.  When no more work is outstanding the outermost will
+    sleep until an event is signalled.

 */
     virtual void threadMain();
 
 public:
 
 /*! @function workLoop
 */
     virtual void threadMain();
 
 public:
 
 /*! @function workLoop

-    @abstract Factory member function to constuct and intialize a work loop.
+    @abstract Factory member function to construct and intialize a work loop.

     @result Returns a workLoop instance if constructed successfully, 0 otherwise. 
 */
     static IOWorkLoop *workLoop();
 
     @result Returns a workLoop instance if constructed successfully, 0 otherwise. 
 */
     static IOWorkLoop *workLoop();
 

+/*! @function workLoopWithOptions(IOOptionBits options)
+    @abstract Factory member function to constuct and intialize a work loop.
+    @param options Options - kPreciousStack to avoid stack deallocation on paging path.
+    @result Returns a workLoop instance if constructed successfully, 0 otherwise. 
+*/
+    static IOWorkLoop *workLoopWithOptions(IOOptionBits options);
+

 /*! @function init
 /*! @function init

-    @discussion Initializes an instance of the workloop.  This method creates and initialses the signaling semaphore and forks the thread that will continue executing.
+    @discussion Initializes an instance of the workloop.  This method creates and initializes the signaling semaphore, the controller gate lock, and spawns the thread that will continue executing.

     @result Returns true if initialized successfully, false otherwise. 
 */
     virtual bool init();
     @result Returns true if initialized successfully, false otherwise. 
 */
     virtual bool init();


@@ -218,13 +249,13 @@ public:
 
 /*! @function enableAllInterrupts
     @abstract Calls enable() in all interrupt event sources.
 
 /*! @function enableAllInterrupts
     @abstract Calls enable() in all interrupt event sources.

-    @discussion For all event sources (ES) for which IODynamicCast(IOInterruptEventSource, ES) is valid, in eventChain call enable() function.  See IOEventSource::enable().
+    @discussion For all event sources (ES) for which OSDynamicCast(IOInterruptEventSource, ES) is valid, in eventChain call enable() function.  See IOEventSource::enable().

 */
     virtual void enableAllInterrupts() const;
 
 /*! @function disableAllInterrupts
     @abstract Calls disable() in all interrupt event sources.
 */
     virtual void enableAllInterrupts() const;
 
 /*! @function disableAllInterrupts
     @abstract Calls disable() in all interrupt event sources.

-    @discussion For all event sources (ES) for which IODynamicCast(IOInterruptEventSource, ES) is valid,  in eventChain call disable() function.  See IOEventSource::disable().
+    @discussion For all event sources (ES) for which OSDynamicCast(IOInterruptEventSource, ES) is valid,  in eventChain call disable() function.  See IOEventSource::disable().

 */
     virtual void disableAllInterrupts() const;
 
 */
     virtual void disableAllInterrupts() const;
 


@@ -233,11 +264,14 @@ protected:
     // Internal APIs used by event sources to control the thread
     friend class IOEventSource;
     friend class IOTimerEventSource;
     // Internal APIs used by event sources to control the thread
     friend class IOEventSource;
     friend class IOTimerEventSource;

+#if IOKITSTATS
+    friend class IOStatistics;
+#endif

     virtual void signalWorkAvailable();
     virtual void openGate();
     virtual void closeGate();
     virtual bool tryCloseGate();
     virtual void signalWorkAvailable();
     virtual void openGate();
     virtual void closeGate();
     virtual bool tryCloseGate();

-    virtual int sleepGate(void *event, UInt32 interuptibleType);
+    virtual int  sleepGate(void *event, UInt32 interuptibleType);

     virtual void wakeupGate(void *event, bool oneThread);
 
 public:
     virtual void wakeupGate(void *event, bool oneThread);
 
 public:


@@ -245,9 +279,7 @@ public:
 
 /*! @function runAction
     @abstract Single thread a call to an action with the work-loop.
 
 /*! @function runAction
     @abstract Single thread a call to an action with the work-loop.

-    @discussion Client function that causes the given action to be called in
-a single threaded manner.  Beware: the work-loop's gate is recursive and runAction can cause direct or indirect re-entrancy.  When executing on a client's thread, runAction will sleep until the work-loop's gate opens for
-execution of client actions, the action is single threaded against all other work-loop event sources.
+    @discussion Client function that causes the given action to be called in a single threaded manner.  Beware: the work-loop's gate is recursive and runAction can cause direct or indirect re-entrancy.  When executing on a client's thread, runAction will sleep until the work-loop's gate opens for execution of client actions, the action is single threaded against all other work-loop event sources.

     @param action Pointer to function to be executed in work-loop context.
     @param arg0 Parameter for action parameter, defaults to 0.
     @param arg1 Parameter for action parameter, defaults to 0.
     @param action Pointer to function to be executed in work-loop context.
     @param arg0 Parameter for action parameter, defaults to 0.
     @param arg1 Parameter for action parameter, defaults to 0.


@@ -259,11 +291,41 @@ execution of client actions, the action is single threaded against all other wor
                               void *arg0 = 0, void *arg1 = 0,
                               void *arg2 = 0, void *arg3 = 0);
 
                               void *arg0 = 0, void *arg1 = 0,
                               void *arg2 = 0, void *arg3 = 0);
 

+/*! @function runEventSources
+    @discussion Consists of the inner 2 loops of the threadMain function(qv).
+    The outer loop terminates when there is no more work, and the inside loop
+    walks the event list calling the checkForWork method in each event source.
+    If an event source has more work to do, it can set the more flag and the
+    outer loop will repeat.
+<br><br>
+    This function can be used to clear a priority inversion between the normal
+    workloop thread and multimedia's real time threads.  The problem is that
+    the interrupt action routine is often held off by high priority threads.
+    So if they want to get their data now they will have to call us and ask if
+    any data is available.  The multi-media user client will arrange for this
+    function to be called, which causes any pending interrupts to be processed
+    and the completion routines called.  By the time the function returns all
+    outstanding work will have been completed at the real time threads
+    priority.
+
+    @result Return false if the work loop is shutting down, true otherwise.
+*/
+    virtual bool runEventSources();
+

 protected:
 protected:

-    OSMetaClassDeclareReservedUsed(IOWorkLoop, 0);
+    // Internal APIs used by event sources to control the thread
+    virtual int sleepGate(void *event, AbsoluteTime deadline, UInt32 interuptibleType);

 
 

+protected:
+#if __LP64__
+    OSMetaClassDeclareReservedUnused(IOWorkLoop, 0);

     OSMetaClassDeclareReservedUnused(IOWorkLoop, 1);
     OSMetaClassDeclareReservedUnused(IOWorkLoop, 2);
     OSMetaClassDeclareReservedUnused(IOWorkLoop, 1);
     OSMetaClassDeclareReservedUnused(IOWorkLoop, 2);

+#else
+    OSMetaClassDeclareReservedUsed(IOWorkLoop, 0);
+    OSMetaClassDeclareReservedUsed(IOWorkLoop, 1);
+    OSMetaClassDeclareReservedUsed(IOWorkLoop, 2);
+#endif

     OSMetaClassDeclareReservedUnused(IOWorkLoop, 3);
     OSMetaClassDeclareReservedUnused(IOWorkLoop, 4);
     OSMetaClassDeclareReservedUnused(IOWorkLoop, 5);
     OSMetaClassDeclareReservedUnused(IOWorkLoop, 3);
     OSMetaClassDeclareReservedUnused(IOWorkLoop, 4);
     OSMetaClassDeclareReservedUnused(IOWorkLoop, 5);