[apple/xnu.git] / iokit / IOKit / ppc / IOSharedLockImp.h

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved. 
 *
 * HISTORY
 *
 */

/* 	Copyright (c) 1992 NeXT Computer, Inc.  All rights reserved. 
 *
 * EventShmemLock.h -	Shared memory area locks for use between the
 *			WindowServer and the Event Driver.
 *
 * HISTORY
 * 30 Nov   1992    Ben Fathi (benf@next.com)
 *      Ported to m98k.
 *
 * 29 April 1992    Mike Paquette at NeXT
 *      Created. 
 *
 * Multiprocessor locks used within the shared memory area between the
 * kernel and event system.  These must work in both user and kernel mode.
 * The locks are defined in an include file so they get exported to the local
 * include file area.
 */


#ifndef _IOKIT_IOSHAREDLOCKIMP_H
#define _IOKIT_IOSHAREDLOCKIMP_H

#include <architecture/ppc/asm_help.h>
#ifdef KERNEL
#undef END
#include <mach/ppc/asm.h>
#endif

/*
 *	void
 *	ev_lock(p)
 *		register int *p;
 *
 *	Lock the lock pointed to by p.  Spin (possibly forever) until
 *		the lock is available.  Test and test and set logic used.
 */
	TEXT

#ifndef KERNEL
LEAF(_ev_lock)

		li		a6,1			// lock value
		
8:		lwz		a7,0(a0)		// Get lock word
		mr.		a7,a7			// Is it held?
		bne--	8b				// Yup...

9:		lwarx	a7,0,a0			// read the lock
		mr.		a7,a7			// Is it held?
		bne--	7f				// yes, kill reservation
		stwcx.	a6,0,a0			// try to get the lock
		bne--	9b 				// failed, try again
		isync
		blr						// got it, return
		
7:		li		a7,-4			// Point to a spot in the red zone
		stwcx.	a7,a7,r1		// Kill reservation
		b		8b				// Go wait some more...
		
		
END(_ev_lock)

LEAF(_IOSpinLock)

		li		a6,1			// lock value
		
8:		lwz		a7,0(a0)		// Get lock word
		mr.		a7,a7			// Is it held?
		bne--	8b				// Yup...

9:		lwarx	a7,0,a0			// read the lock
		mr.		a7,a7			// Is it held?
		bne--	7f				// yes, kill reservation
		stwcx.	a6,0,a0			// try to get the lock
		bne--	9b 				// failed, try again
		isync
		blr						// got it, return
		
7:		li		a7,-4			// Point to a spot in the red zone
		stwcx.	a7,a7,r1		// Kill reservation
		b		8b				// Go wait some more...
END(_IOSpinLock)
#endif

/*
 *	void
 *	spin_unlock(p)
 *		int *p;
 *
 *	Unlock the lock pointed to by p.
 */

LEAF(_ev_unlock)
	sync
	li	a7,0
	stw	a7,0(a0)
	blr
END(_ev_unlock)

LEAF(_IOSpinUnlock)
	sync
	li	a7,0
	stw	a7,0(a0)
	blr
END(_IOSpinUnlock)


/*
 *	ev_try_lock(p)
 *		int *p;
 *
 *	Try to lock p.  Return TRUE if successful in obtaining lock.
 */

LEAF(_ev_try_lock)
		li		a6,1			// lock value
		
		lwz		a7,0(a0)		// Get lock word
		mr.		a7,a7			// Is it held?
		bne--	6f				// Yup...

9:		lwarx	a7,0,a0			// read the lock
		mr.		a7,a7			// Is it held?
		bne--	7f				// yes, kill reservation
		stwcx.	a6,0,a0			// try to get the lock
		bne--	9b 				// failed, try again
		li		a0,1			// return TRUE
		isync
		blr						// got it, return
		
7:		li		a7,-4			// Point to a spot in the red zone
		stwcx.	a7,a7,r1		// Kill reservation

6:
		li	a0,0				// return FALSE
		blr
		
END(_ev_try_lock)

LEAF(_IOTrySpinLock)
		li		a6,1			// lock value
		
		lwz		a7,0(a0)		// Get lock word
		mr.		a7,a7			// Is it held?
		bne--	6f				// Yup...

9:		lwarx	a7,0,a0			// read the lock
		mr.		a7,a7			// Is it held?
		bne--	7f				// yes, kill reservation
		stwcx.	a6,0,a0			// try to get the lock
		bne--	9b 				// failed, try again
		li		a0,1			// return TRUE
		isync
		blr						// got it, return
		
7:		li		a7,-4			// Point to a spot in the red zone
		stwcx.	a7,a7,r1		// Kill reservation

6:
		li	a0,0				// return FALSE
		blr
		
END(_IOTrySpinLock)

#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
2d21ac55 A	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.
8f6c56a5	14	*
2d21ac55 A	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
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
8f6c56a5	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b A	27	*/
	28	/*
	29	* Copyright (c) 1998 Apple Computer, Inc. All rights reserved.
	30	*
	31	* HISTORY
	32	*
	33	*/
	34
	35	/* Copyright (c) 1992 NeXT Computer, Inc. All rights reserved.
	36	*
	37	* EventShmemLock.h - Shared memory area locks for use between the
	38	* WindowServer and the Event Driver.
	39	*
	40	* HISTORY
	41	* 30 Nov 1992 Ben Fathi (benf@next.com)
	42	* Ported to m98k.
	43	*
	44	* 29 April 1992 Mike Paquette at NeXT
	45	* Created.
	46	*
	47	* Multiprocessor locks used within the shared memory area between the
	48	* kernel and event system. These must work in both user and kernel mode.
	49	* The locks are defined in an include file so they get exported to the local
	50	* include file area.
	51	*/
	52
	53
	54	#ifndef _IOKIT_IOSHAREDLOCKIMP_H
	55	#define _IOKIT_IOSHAREDLOCKIMP_H
	56
	57	#include <architecture/ppc/asm_help.h>
7b1edb79 A	58	#ifdef KERNEL
	59	#undef END
	60	#include <mach/ppc/asm.h>
	61	#endif
1c79356b	62
1c79356b A	63	/*
	64	* void
	65	* ev_lock(p)
	66	* register int *p;
	67	*
	68	* Lock the lock pointed to by p. Spin (possibly forever) until
	69	* the lock is available. Test and test and set logic used.
	70	*/
	71	TEXT
	72
	73	#ifndef KERNEL
	74	LEAF(_ev_lock)
55e303ae A	75
	76	li a6,1 // lock value
	77
	78	8: lwz a7,0(a0) // Get lock word
	79	mr. a7,a7 // Is it held?
	80	bne-- 8b // Yup...
	81
	82	9: lwarx a7,0,a0 // read the lock
	83	mr. a7,a7 // Is it held?
	84	bne-- 7f // yes, kill reservation
	85	stwcx. a6,0,a0 // try to get the lock
	86	bne-- 9b // failed, try again
	87	isync
	88	blr // got it, return
	89
	90	7: li a7,-4 // Point to a spot in the red zone
	91	stwcx. a7,a7,r1 // Kill reservation
	92	b 8b // Go wait some more...
	93
	94
1c79356b	95	END(_ev_lock)
0b4e3aa0 A	96
0b4e3aa0 A	97	LEAF(_IOSpinLock)
55e303ae A	98
	99	li a6,1 // lock value
	100
	101	8: lwz a7,0(a0) // Get lock word
	102	mr. a7,a7 // Is it held?
	103	bne-- 8b // Yup...
	104
	105	9: lwarx a7,0,a0 // read the lock
	106	mr. a7,a7 // Is it held?
	107	bne-- 7f // yes, kill reservation
	108	stwcx. a6,0,a0 // try to get the lock
	109	bne-- 9b // failed, try again
	110	isync
	111	blr // got it, return
	112
	113	7: li a7,-4 // Point to a spot in the red zone
	114	stwcx. a7,a7,r1 // Kill reservation
	115	b 8b // Go wait some more...
0b4e3aa0	116	END(_IOSpinLock)
1c79356b A	117	#endif
	118
	119	/*
	120	* void
	121	* spin_unlock(p)
	122	* int *p;
	123	*
	124	* Unlock the lock pointed to by p.
	125	*/
	126
	127	LEAF(_ev_unlock)
1c79356b A	128	sync
	129	li a7,0
	130	stw a7,0(a0)
1c79356b A	131	blr
	132	END(_ev_unlock)
	133
0b4e3aa0 A	134	LEAF(_IOSpinUnlock)
	135	sync
	136	li a7,0
	137	stw a7,0(a0)
0b4e3aa0 A	138	blr
	139	END(_IOSpinUnlock)
	140
1c79356b A	141
	142	/*
	143	* ev_try_lock(p)
	144	* int *p;
	145	*
	146	* Try to lock p. Return TRUE if successful in obtaining lock.
	147	*/
	148
	149	LEAF(_ev_try_lock)
55e303ae A	150	li a6,1 // lock value
	151
	152	lwz a7,0(a0) // Get lock word
	153	mr. a7,a7 // Is it held?
	154	bne-- 6f // Yup...
	155
	156	9: lwarx a7,0,a0 // read the lock
	157	mr. a7,a7 // Is it held?
	158	bne-- 7f // yes, kill reservation
	159	stwcx. a6,0,a0 // try to get the lock
	160	bne-- 9b // failed, try again
	161	li a0,1 // return TRUE
	162	isync
	163	blr // got it, return
	164
	165	7: li a7,-4 // Point to a spot in the red zone
	166	stwcx. a7,a7,r1 // Kill reservation
	167
	168	6:
55e303ae A	169	li a0,0 // return FALSE
	170	blr
	171
1c79356b A	172	END(_ev_try_lock)
1c79356b A	173
0b4e3aa0	174	LEAF(_IOTrySpinLock)
55e303ae A	175	li a6,1 // lock value
	176
	177	lwz a7,0(a0) // Get lock word
	178	mr. a7,a7 // Is it held?
	179	bne-- 6f // Yup...
	180
	181	9: lwarx a7,0,a0 // read the lock
	182	mr. a7,a7 // Is it held?
	183	bne-- 7f // yes, kill reservation
	184	stwcx. a6,0,a0 // try to get the lock
	185	bne-- 9b // failed, try again
	186	li a0,1 // return TRUE
	187	isync
	188	blr // got it, return
	189
	190	7: li a7,-4 // Point to a spot in the red zone
	191	stwcx. a7,a7,r1 // Kill reservation
	192
	193	6:
55e303ae A	194	li a0,0 // return FALSE
	195	blr
	196
0b4e3aa0 A	197	END(_IOTrySpinLock)
0b4e3aa0 A	198
1c79356b	199	#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */