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

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_OSREFERENCE_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_LICENSE_OSREFERENCE_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	*
8ad349bb	4	* @APPLE_LICENSE_OSREFERENCE_HEADER_START@
1c79356b	5	*
8ad349bb 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
	10	* License may not be used to create, or enable the creation or
	11	* redistribution of, unlawful or unlicensed copies of an Apple operating
	12	* system, or to circumvent, violate, or enable the circumvention or
	13	* violation of, any terms of an Apple operating system software license
	14	* agreement.
	15	*
	16	* Please obtain a copy of the License at
	17	* http://www.opensource.apple.com/apsl/ and read it before using this
	18	* file.
	19	*
	20	* The Original Code and all software distributed under the License are
	21	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	22	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	23	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	24	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	25	* Please see the License for the specific language governing rights and
	26	* limitations under the License.
	27	*
	28	* @APPLE_LICENSE_OSREFERENCE_HEADER_END@
1c79356b A	29	*/
	30	/*
	31	* Copyright (c) 1998 Apple Computer, Inc. All rights reserved.
	32	*
	33	* HISTORY
	34	*
	35	*/
	36
	37	/* Copyright (c) 1992 NeXT Computer, Inc. All rights reserved.
	38	*
	39	* EventShmemLock.h - Shared memory area locks for use between the
	40	* WindowServer and the Event Driver.
	41	*
	42	* HISTORY
	43	* 30 Nov 1992 Ben Fathi (benf@next.com)
	44	* Ported to m98k.
	45	*
	46	* 29 April 1992 Mike Paquette at NeXT
	47	* Created.
	48	*
	49	* Multiprocessor locks used within the shared memory area between the
	50	* kernel and event system. These must work in both user and kernel mode.
	51	* The locks are defined in an include file so they get exported to the local
	52	* include file area.
	53	*/
	54
	55
	56	#ifndef _IOKIT_IOSHAREDLOCKIMP_H
	57	#define _IOKIT_IOSHAREDLOCKIMP_H
	58
	59	#include <architecture/ppc/asm_help.h>
7b1edb79 A	60	#ifdef KERNEL
	61	#undef END
	62	#include <mach/ppc/asm.h>
	63	#endif
1c79356b	64
1c79356b A	65	/*
	66	* void
	67	* ev_lock(p)
	68	* register int *p;
	69	*
	70	* Lock the lock pointed to by p. Spin (possibly forever) until
	71	* the lock is available. Test and test and set logic used.
	72	*/
	73	TEXT
	74
	75	#ifndef KERNEL
	76	LEAF(_ev_lock)
55e303ae A	77
	78	li a6,1 // lock value
	79
	80	8: lwz a7,0(a0) // Get lock word
	81	mr. a7,a7 // Is it held?
	82	bne-- 8b // Yup...
	83
	84	9: lwarx a7,0,a0 // read the lock
	85	mr. a7,a7 // Is it held?
	86	bne-- 7f // yes, kill reservation
	87	stwcx. a6,0,a0 // try to get the lock
	88	bne-- 9b // failed, try again
	89	isync
	90	blr // got it, return
	91
	92	7: li a7,-4 // Point to a spot in the red zone
	93	stwcx. a7,a7,r1 // Kill reservation
	94	b 8b // Go wait some more...
	95
	96
1c79356b	97	END(_ev_lock)
0b4e3aa0 A	98
0b4e3aa0 A	99	LEAF(_IOSpinLock)
55e303ae A	100
	101	li a6,1 // lock value
	102
	103	8: lwz a7,0(a0) // Get lock word
	104	mr. a7,a7 // Is it held?
	105	bne-- 8b // Yup...
	106
	107	9: lwarx a7,0,a0 // read the lock
	108	mr. a7,a7 // Is it held?
	109	bne-- 7f // yes, kill reservation
	110	stwcx. a6,0,a0 // try to get the lock
	111	bne-- 9b // failed, try again
	112	isync
	113	blr // got it, return
	114
	115	7: li a7,-4 // Point to a spot in the red zone
	116	stwcx. a7,a7,r1 // Kill reservation
	117	b 8b // Go wait some more...
0b4e3aa0	118	END(_IOSpinLock)
1c79356b A	119	#endif
	120
	121	/*
	122	* void
	123	* spin_unlock(p)
	124	* int *p;
	125	*
	126	* Unlock the lock pointed to by p.
	127	*/
	128
	129	LEAF(_ev_unlock)
1c79356b A	130	sync
	131	li a7,0
	132	stw a7,0(a0)
1c79356b A	133	blr
	134	END(_ev_unlock)
	135
0b4e3aa0 A	136	LEAF(_IOSpinUnlock)
	137	sync
	138	li a7,0
	139	stw a7,0(a0)
0b4e3aa0 A	140	blr
	141	END(_IOSpinUnlock)
	142
1c79356b A	143
	144	/*
	145	* ev_try_lock(p)
	146	* int *p;
	147	*
	148	* Try to lock p. Return TRUE if successful in obtaining lock.
	149	*/
	150
	151	LEAF(_ev_try_lock)
55e303ae A	152	li a6,1 // lock value
	153
	154	lwz a7,0(a0) // Get lock word
	155	mr. a7,a7 // Is it held?
	156	bne-- 6f // Yup...
	157
	158	9: lwarx a7,0,a0 // read the lock
	159	mr. a7,a7 // Is it held?
	160	bne-- 7f // yes, kill reservation
	161	stwcx. a6,0,a0 // try to get the lock
	162	bne-- 9b // failed, try again
	163	li a0,1 // return TRUE
	164	isync
	165	blr // got it, return
	166
	167	7: li a7,-4 // Point to a spot in the red zone
	168	stwcx. a7,a7,r1 // Kill reservation
	169
	170	6:
55e303ae A	171	li a0,0 // return FALSE
	172	blr
	173
1c79356b A	174	END(_ev_try_lock)
1c79356b A	175
0b4e3aa0	176	LEAF(_IOTrySpinLock)
55e303ae A	177	li a6,1 // lock value
	178
	179	lwz a7,0(a0) // Get lock word
	180	mr. a7,a7 // Is it held?
	181	bne-- 6f // Yup...
	182
	183	9: lwarx a7,0,a0 // read the lock
	184	mr. a7,a7 // Is it held?
	185	bne-- 7f // yes, kill reservation
	186	stwcx. a6,0,a0 // try to get the lock
	187	bne-- 9b // failed, try again
	188	li a0,1 // return TRUE
	189	isync
	190	blr // got it, return
	191
	192	7: li a7,-4 // Point to a spot in the red zone
	193	stwcx. a7,a7,r1 // Kill reservation
	194
	195	6:
55e303ae A	196	li a0,0 // return FALSE
	197	blr
	198
0b4e3aa0 A	199	END(_IOTrySpinLock)
0b4e3aa0 A	200
1c79356b	201	#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */