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acpi_func.h revision 1.2 
      1 /*	$NetBSD: acpi_func.h,v 1.2 2010/03/08 12:35:08 jruoho Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2000 Michael Smith
      5  * Copyright (c) 2000 BSDi
      6  * Copyright (c) 2007-2009 Jung-uk Kim <jkim (at) FreeBSD.org>
      7  * All rights reserved.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  */
     30 
     31 #include <machine/cpufunc.h>
     32 
     33 #include <sys/atomic.h>
     34 
     35 #define GL_ACQUIRED	(-1)
     36 #define GL_BUSY		0
     37 #define GL_BIT_PENDING	1
     38 #define GL_BIT_OWNED	2
     39 #define GL_BIT_MASK	(GL_BIT_PENDING | GL_BIT_OWNED)
     40 
     41 #define ACPI_ACQUIRE_GLOBAL_LOCK(GLptr, Acq) 				\
     42 do { 									\
     43 	(Acq) = acpi_acquire_global_lock(&((GLptr)->GlobalLock));	\
     44 } while (0)
     45 
     46 #define ACPI_RELEASE_GLOBAL_LOCK(GLptr, Acq) 				\
     47 do {									\
     48 	(Acq) = acpi_release_global_lock(&((GLptr)->GlobalLock));	\
     49 } while (0)
     50 
     51 static inline int
     52 acpi_acquire_global_lock(uint32_t *lock)
     53 {
     54 	uint32_t new, old, val;
     55 
     56 	do {
     57 		old = *lock;
     58 		new = ((old & ~GL_BIT_MASK) | GL_BIT_OWNED) |
     59 		    ((old >> 1) & GL_BIT_PENDING);
     60 		val = atomic_cas_32(lock, old, new);
     61 	} while (__predict_false(val != old));
     62 
     63 	return ((new < GL_BIT_MASK) ? GL_ACQUIRED : GL_BUSY);
     64 }
     65 
     66 static inline int
     67 acpi_release_global_lock(uint32_t *lock)
     68 {
     69 	uint32_t new, old, val;
     70 
     71 	do {
     72 		old = *lock;
     73 		new = old & ~GL_BIT_MASK;
     74 		val = atomic_cas_32(lock, old, new);
     75 	} while (__predict_false(val != old));
     76 
     77 	return old & GL_BIT_PENDING;
     78 }
     79 
     80 #define	ACPI_FLUSH_CPU_CACHE()		wbinvd()
     81