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

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_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. 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_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	*
ff6e181a 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. Please obtain a copy of the License at
	10	* http://www.opensource.apple.com/apsl/ and read it before using this
	11	* file.
1c79356b	12	*
ff6e181a A	13	* The Original Code and all software distributed under the License are
ff6e181a A	14	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	15	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	16	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
ff6e181a A	17	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	18	* Please see the License for the specific language governing rights and
	19	* limitations under the License.
1c79356b A	20	*
	21	* @APPLE_LICENSE_HEADER_END@
	22	*/
	23	/*
	24	* Copyright (c) 1998 Apple Computer, Inc. All rights reserved.
	25	*
	26	* HISTORY
	27	*
	28	*/
	29
	30	/* Copyright (c) 1992 NeXT Computer, Inc. All rights reserved.
	31	*
	32	* EventShmemLock.h - Shared memory area locks for use between the
	33	* WindowServer and the Event Driver.
	34	*
	35	* HISTORY
	36	* 30 Nov 1992 Ben Fathi (benf@next.com)
	37	* Ported to m98k.
	38	*
	39	* 29 April 1992 Mike Paquette at NeXT
	40	* Created.
	41	*
	42	* Multiprocessor locks used within the shared memory area between the
	43	* kernel and event system. These must work in both user and kernel mode.
	44	* The locks are defined in an include file so they get exported to the local
	45	* include file area.
	46	*/
	47
	48
	49	#ifndef _IOKIT_IOSHAREDLOCKIMP_H
	50	#define _IOKIT_IOSHAREDLOCKIMP_H
	51
	52	#include <architecture/ppc/asm_help.h>
7b1edb79 A	53	#ifdef KERNEL
	54	#undef END
	55	#include <mach/ppc/asm.h>
	56	#endif
1c79356b	57
1c79356b A	58	/*
	59	* void
	60	* ev_lock(p)
	61	* register int *p;
	62	*
	63	* Lock the lock pointed to by p. Spin (possibly forever) until
	64	* the lock is available. Test and test and set logic used.
	65	*/
	66	TEXT
	67
	68	#ifndef KERNEL
	69	LEAF(_ev_lock)
55e303ae A	70
	71	li a6,1 // lock value
	72
	73	8: lwz a7,0(a0) // Get lock word
	74	mr. a7,a7 // Is it held?
	75	bne-- 8b // Yup...
	76
	77	9: lwarx a7,0,a0 // read the lock
	78	mr. a7,a7 // Is it held?
	79	bne-- 7f // yes, kill reservation
	80	stwcx. a6,0,a0 // try to get the lock
	81	bne-- 9b // failed, try again
	82	isync
	83	blr // got it, return
	84
	85	7: li a7,-4 // Point to a spot in the red zone
	86	stwcx. a7,a7,r1 // Kill reservation
	87	b 8b // Go wait some more...
	88
	89
1c79356b	90	END(_ev_lock)
0b4e3aa0 A	91
0b4e3aa0 A	92	LEAF(_IOSpinLock)
55e303ae A	93
	94	li a6,1 // lock value
	95
	96	8: lwz a7,0(a0) // Get lock word
	97	mr. a7,a7 // Is it held?
	98	bne-- 8b // Yup...
	99
	100	9: lwarx a7,0,a0 // read the lock
	101	mr. a7,a7 // Is it held?
	102	bne-- 7f // yes, kill reservation
	103	stwcx. a6,0,a0 // try to get the lock
	104	bne-- 9b // failed, try again
	105	isync
	106	blr // got it, return
	107
	108	7: li a7,-4 // Point to a spot in the red zone
	109	stwcx. a7,a7,r1 // Kill reservation
	110	b 8b // Go wait some more...
0b4e3aa0	111	END(_IOSpinLock)
1c79356b A	112	#endif
	113
	114	/*
	115	* void
	116	* spin_unlock(p)
	117	* int *p;
	118	*
	119	* Unlock the lock pointed to by p.
	120	*/
	121
	122	LEAF(_ev_unlock)
1c79356b A	123	sync
	124	li a7,0
	125	stw a7,0(a0)
1c79356b A	126	blr
	127	END(_ev_unlock)
	128
0b4e3aa0 A	129	LEAF(_IOSpinUnlock)
	130	sync
	131	li a7,0
	132	stw a7,0(a0)
0b4e3aa0 A	133	blr
	134	END(_IOSpinUnlock)
	135
1c79356b A	136
	137	/*
	138	* ev_try_lock(p)
	139	* int *p;
	140	*
	141	* Try to lock p. Return TRUE if successful in obtaining lock.
	142	*/
	143
	144	LEAF(_ev_try_lock)
55e303ae A	145	li a6,1 // lock value
	146
	147	lwz a7,0(a0) // Get lock word
	148	mr. a7,a7 // Is it held?
	149	bne-- 6f // Yup...
	150
	151	9: lwarx a7,0,a0 // read the lock
	152	mr. a7,a7 // Is it held?
	153	bne-- 7f // yes, kill reservation
	154	stwcx. a6,0,a0 // try to get the lock
	155	bne-- 9b // failed, try again
	156	li a0,1 // return TRUE
	157	isync
	158	blr // got it, return
	159
	160	7: li a7,-4 // Point to a spot in the red zone
	161	stwcx. a7,a7,r1 // Kill reservation
	162
	163	6:
55e303ae A	164	li a0,0 // return FALSE
	165	blr
	166
1c79356b A	167	END(_ev_try_lock)
1c79356b A	168
0b4e3aa0	169	LEAF(_IOTrySpinLock)
55e303ae A	170	li a6,1 // lock value
	171
	172	lwz a7,0(a0) // Get lock word
	173	mr. a7,a7 // Is it held?
	174	bne-- 6f // Yup...
	175
	176	9: lwarx a7,0,a0 // read the lock
	177	mr. a7,a7 // Is it held?
	178	bne-- 7f // yes, kill reservation
	179	stwcx. a6,0,a0 // try to get the lock
	180	bne-- 9b // failed, try again
	181	li a0,1 // return TRUE
	182	isync
	183	blr // got it, return
	184
	185	7: li a7,-4 // Point to a spot in the red zone
	186	stwcx. a7,a7,r1 // Kill reservation
	187
	188	6:
55e303ae A	189	li a0,0 // return FALSE
	190	blr
	191
0b4e3aa0 A	192	END(_IOTrySpinLock)
0b4e3aa0 A	193
1c79356b	194	#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */