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

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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 OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_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	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
e5568f75 A	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.
1c79356b	11	*
e5568f75 A	12	* This Original Code and all software distributed under the License are
e5568f75 A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
e5568f75 A	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.
1c79356b A	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	/* Copyright (c) 1992 NeXT Computer, Inc. All rights reserved.
	30	*
	31	* EventShmemLock.h - Shared memory area locks for use between the
	32	* WindowServer and the Event Driver.
	33	*
	34	* HISTORY
	35	* 30 Nov 1992 Ben Fathi (benf@next.com)
	36	* Ported to m98k.
	37	*
	38	* 29 April 1992 Mike Paquette at NeXT
	39	* Created.
	40	*
	41	* Multiprocessor locks used within the shared memory area between the
	42	* kernel and event system. These must work in both user and kernel mode.
	43	* The locks are defined in an include file so they get exported to the local
	44	* include file area.
	45	*/
	46
	47
	48	#ifndef _IOKIT_IOSHAREDLOCKIMP_H
	49	#define _IOKIT_IOSHAREDLOCKIMP_H
	50
	51	#include <architecture/ppc/asm_help.h>
7b1edb79 A	52	#ifdef KERNEL
	53	#undef END
	54	#include <mach/ppc/asm.h>
	55	#endif
1c79356b	56
1c79356b A	57	/*
	58	* void
	59	* ev_lock(p)
	60	* register int *p;
	61	*
	62	* Lock the lock pointed to by p. Spin (possibly forever) until
	63	* the lock is available. Test and test and set logic used.
	64	*/
	65	TEXT
	66
	67	#ifndef KERNEL
	68	LEAF(_ev_lock)
55e303ae A	69
	70	li a6,1 // lock value
	71
	72	8: lwz a7,0(a0) // Get lock word
	73	mr. a7,a7 // Is it held?
	74	bne-- 8b // Yup...
	75
	76	9: lwarx a7,0,a0 // read the lock
	77	mr. a7,a7 // Is it held?
	78	bne-- 7f // yes, kill reservation
	79	stwcx. a6,0,a0 // try to get the lock
	80	bne-- 9b // failed, try again
	81	isync
	82	blr // got it, return
	83
	84	7: li a7,-4 // Point to a spot in the red zone
	85	stwcx. a7,a7,r1 // Kill reservation
	86	b 8b // Go wait some more...
	87
	88
1c79356b	89	END(_ev_lock)
0b4e3aa0 A	90
0b4e3aa0 A	91	LEAF(_IOSpinLock)
55e303ae A	92
	93	li a6,1 // lock value
	94
	95	8: lwz a7,0(a0) // Get lock word
	96	mr. a7,a7 // Is it held?
	97	bne-- 8b // Yup...
	98
	99	9: lwarx a7,0,a0 // read the lock
	100	mr. a7,a7 // Is it held?
	101	bne-- 7f // yes, kill reservation
	102	stwcx. a6,0,a0 // try to get the lock
	103	bne-- 9b // failed, try again
	104	isync
	105	blr // got it, return
	106
	107	7: li a7,-4 // Point to a spot in the red zone
	108	stwcx. a7,a7,r1 // Kill reservation
	109	b 8b // Go wait some more...
0b4e3aa0	110	END(_IOSpinLock)
1c79356b A	111	#endif
	112
	113	/*
	114	* void
	115	* spin_unlock(p)
	116	* int *p;
	117	*
	118	* Unlock the lock pointed to by p.
	119	*/
	120
	121	LEAF(_ev_unlock)
1c79356b A	122	sync
	123	li a7,0
	124	stw a7,0(a0)
1c79356b A	125	blr
	126	END(_ev_unlock)
	127
0b4e3aa0 A	128	LEAF(_IOSpinUnlock)
	129	sync
	130	li a7,0
	131	stw a7,0(a0)
0b4e3aa0 A	132	blr
	133	END(_IOSpinUnlock)
	134
1c79356b A	135
	136	/*
	137	* ev_try_lock(p)
	138	* int *p;
	139	*
	140	* Try to lock p. Return TRUE if successful in obtaining lock.
	141	*/
	142
	143	LEAF(_ev_try_lock)
55e303ae A	144	li a6,1 // lock value
	145
	146	lwz a7,0(a0) // Get lock word
	147	mr. a7,a7 // Is it held?
	148	bne-- 6f // Yup...
	149
	150	9: lwarx a7,0,a0 // read the lock
	151	mr. a7,a7 // Is it held?
	152	bne-- 7f // yes, kill reservation
	153	stwcx. a6,0,a0 // try to get the lock
	154	bne-- 9b // failed, try again
	155	li a0,1 // return TRUE
	156	isync
	157	blr // got it, return
	158
	159	7: li a7,-4 // Point to a spot in the red zone
	160	stwcx. a7,a7,r1 // Kill reservation
	161
	162	6:
55e303ae A	163	li a0,0 // return FALSE
	164	blr
	165
1c79356b A	166	END(_ev_try_lock)
1c79356b A	167
0b4e3aa0	168	LEAF(_IOTrySpinLock)
55e303ae A	169	li a6,1 // lock value
	170
	171	lwz a7,0(a0) // Get lock word
	172	mr. a7,a7 // Is it held?
	173	bne-- 6f // Yup...
	174
	175	9: lwarx a7,0,a0 // read the lock
	176	mr. a7,a7 // Is it held?
	177	bne-- 7f // yes, kill reservation
	178	stwcx. a6,0,a0 // try to get the lock
	179	bne-- 9b // failed, try again
	180	li a0,1 // return TRUE
	181	isync
	182	blr // got it, return
	183
	184	7: li a7,-4 // Point to a spot in the red zone
	185	stwcx. a7,a7,r1 // Kill reservation
	186
	187	6:
55e303ae A	188	li a0,0 // return FALSE
	189	blr
	190
0b4e3aa0 A	191	END(_IOTrySpinLock)
0b4e3aa0 A	192
1c79356b	193	#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */