iokit/IOKit/IOSharedLock.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
  27  *
  28  * HISTORY
  29  *
  30  */
  31
  32 /*
  33  * Multiprocessor locks used within the shared memory area between the
  34  * kernel and event system.  These must work in both user and kernel mode.
  35  *
  36  * These routines are public, for the purpose of writing frame buffer device
  37  * drivers which handle their own cursors.  Certain architectures define a
  38  * generic display class which handles cursor drawing and is subclassed by
  39  * driver writers.  These drivers need not be concerned with the following
  40  * types and definitions.
  41  *
  42  * The ev_lock(), ev_unlock(), and ev_try_lock() functions are available only
  43  * to drivers built in or dynamically loaded into the kernel, and to DPS
  44  * drivers built in or dynamically loaded into the Window Server.  They do not
  45  * exist in any shared library.
  46  *
  47  * --> They're now in IOKit user lib.
  48  */
  49
  50 #ifndef _IOKIT_IOSHAREDLOCK_H
  51 #define _IOKIT_IOSHAREDLOCK_H
  52
  53 #ifdef __cplusplus
  54 extern "C" {
  55 #endif
  56
  57 // should be 32 bytes on PPC
  58 typedef volatile int            IOSharedLockData;
  59 typedef IOSharedLockData    *   IOSharedLock;
  60
  61 #define IOSpinLockInit(l)       (*(l) = (IOSpinLockData)0)
  62
  63 extern void IOSpinLock(IOSharedLock l);
  64 extern void IOSpinUnlock(IOSharedLock l);
  65 extern boolean_t IOTrySpinLock(IOSharedLock l);
  66
  67 /* exact same stuff & implementation */
  68
  69 typedef IOSharedLockData        ev_lock_data_t;
  70 typedef ev_lock_data_t      *   ev_lock_t;
  71
  72 #define ev_init_lock(l)         (*(l) = (ev_lock_data_t)0)
  73 // needs isync?
  74 //#define ev_is_locked(l)       (*(l) != (ev_lock_data_t)0)
  75
  76 extern void ev_lock(ev_lock_t l);               // Spin lock!
  77 extern void ev_unlock(ev_lock_t l);
  78 extern boolean_t ev_try_lock(ev_lock_t l);
  79
  80 #ifdef __cplusplus
  81 }
  82 #endif
  83 #endif /* ! _IOKIT_IOSHAREDLOCK_H */