iokit/IOKit/IOSharedLock.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
  24  *
  25  * HISTORY
  26  *
  27  */
  28
  29 /*
  30  * Multiprocessor locks used within the shared memory area between the
  31  * kernel and event system.  These must work in both user and kernel mode.
  32  *
  33  * These routines are public, for the purpose of writing frame buffer device
  34  * drivers which handle their own cursors.  Certain architectures define a
  35  * generic display class which handles cursor drawing and is subclassed by
  36  * driver writers.  These drivers need not be concerned with the following
  37  * types and definitions.
  38  *
  39  * The ev_lock(), ev_unlock(), and ev_try_lock() functions are available only
  40  * to drivers built in or dynamically loaded into the kernel, and to DPS
  41  * drivers built in or dynamically loaded into the Window Server.  They do not
  42  * exist in any shared library.
  43  *
  44  * --> They're now in IOKit user lib.
  45  */
  46
  47 #ifndef _IOKIT_IOSHAREDLOCK_H
  48 #define _IOKIT_IOSHAREDLOCK_H
  49
  50 #ifdef __cplusplus
  51 extern "C" {
  52 #endif
  53
  54 // should be 32 bytes on PPC
  55 typedef volatile int            IOSharedLockData;
  56 typedef IOSharedLockData    *   IOSharedLock;
  57
  58 #define IOSpinLockInit(l)       (*(l) = (IOSpinLockData)0)
  59
  60 extern void IOSpinLock(IOSharedLock l);
  61 extern void IOSpinUnlock(IOSharedLock l);
  62 extern boolean_t IOTrySpinLock(IOSharedLock l);
  63
  64 /* exact same stuff & implementation */
  65
  66 typedef IOSharedLockData        ev_lock_data_t;
  67 typedef ev_lock_data_t      *   ev_lock_t;
  68
  69 #define ev_init_lock(l)         (*(l) = (ev_lock_data_t)0)
  70 // needs isync?
  71 //#define ev_is_locked(l)       (*(l) != (ev_lock_data_t)0)
  72
  73 extern void ev_lock(ev_lock_t l);               // Spin lock!
  74 extern void ev_unlock(ev_lock_t l);
  75 extern boolean_t ev_try_lock(ev_lock_t l);
  76
  77 #ifdef __cplusplus
  78 }
  79 #endif
  80 #endif /* ! _IOKIT_IOSHAREDLOCK_H */