WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/synch/semaphore.c


/*
 * Copyright (C) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#include <synch/semaphore.h>
#include <synch/waitq.h>
#include <synch/spinlock.h>
#include <synch/synch.h>
#include <arch/asm.h>
#include <arch.h>
 
/** Initialize semaphore
 *
 * Initialize semaphore.
 *
 * @param s Semaphore.
 * @param val Maximal number of threads allowed to enter critical section.
 */
void semaphore_initialize(semaphore_t *s, int val)
{
    ipl_t ipl;
   
    waitq_initialize(&s->wq);
   
    ipl = interrupts_disable();
 
    spinlock_lock(&s->wq.lock);
    s->wq.missed_wakeups = val;
    spinlock_unlock(&s->wq.lock);
 
    interrupts_restore(ipl);
}
 
/** Semaphore down
 *
 * Semaphore down.
 * Conditional mode and mode with timeout can be requested.
 *
 * @param s Semaphore.
 * @param usec Timeout in microseconds.
 * @param trydown Switches between blocking and non-blocking mode.
 *
 * For exact description of possible combinations of
 * usec and trydown, see comment for waitq_sleep_timeout().
 *
 * @return See comment for waitq_sleep_timeout().
 */
int _semaphore_down_timeout(semaphore_t *s, __u32 usec, int trydown)
{
    return waitq_sleep_timeout(&s->wq, usec, trydown);
}
 
/** Semaphore up
 *
 * Semaphore up.
 *
 * @param s Semaphore.
 */
void semaphore_up(semaphore_t *s)
{
    waitq_wakeup(&s->wq, WAKEUP_FIRST);
}
 

Rev 1229	Rev 1248
1	/*	1	/*
2	* Copyright (C) 2001-2004 Jakub Jermar	2	* Copyright (C) 2001-2004 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	#include <synch/semaphore.h>	29	#include <synch/semaphore.h>
30	#include <synch/waitq.h>	30	#include <synch/waitq.h>
31	#include <synch/spinlock.h>	31	#include <synch/spinlock.h>
32	#include <synch/synch.h>	32	#include <synch/synch.h>
33	#include <arch/asm.h>	33	#include <arch/asm.h>
34	#include <arch.h>	34	#include <arch.h>
35		35
36	/** Initialize semaphore	36	/** Initialize semaphore
37	*	37	*
38	* Initialize semaphore.	38	* Initialize semaphore.
39	*	39	*
40	* @param s Semaphore.	40	* @param s Semaphore.
41	* @param val Maximal number of threads allowed to enter critical section.	41	* @param val Maximal number of threads allowed to enter critical section.
42	*/	42	*/
43	void semaphore_initialize(semaphore_t *s, int val)	43	void semaphore_initialize(semaphore_t *s, int val)
44	{	44	{
45	ipl_t ipl;	45	ipl_t ipl;
46		46
47	waitq_initialize(&s->wq);	47	waitq_initialize(&s->wq);
48		48
49	ipl = interrupts_disable();	49	ipl = interrupts_disable();
50		50
51	spinlock_lock(&s->wq.lock);	51	spinlock_lock(&s->wq.lock);
52	s->wq.missed_wakeups = val;	52	s->wq.missed_wakeups = val;
53	spinlock_unlock(&s->wq.lock);	53	spinlock_unlock(&s->wq.lock);
54		54
55	interrupts_restore(ipl);	55	interrupts_restore(ipl);
56	}	56	}
57		57
58	/** Semaphore down	58	/** Semaphore down
59	*	59	*
60	* Semaphore down.	60	* Semaphore down.
61	* Conditional mode and mode with timeout can be requested.	61	* Conditional mode and mode with timeout can be requested.
62	*	62	*
63	* @param s Semaphore.	63	* @param s Semaphore.
64	* @param usec Timeout in microseconds.	64	* @param usec Timeout in microseconds.
65	* @param trydown Switches between blocking and non-blocking mode.	65	* @param trydown Switches between blocking and non-blocking mode.
66	*	66	*
67	* For exact description of possible combinations of	67	* For exact description of possible combinations of
68	* @usec and @trydown, see comment for waitq_sleep_timeout().	68	* usec and trydown, see comment for waitq_sleep_timeout().
69	*	69	*
70	* @return See comment for waitq_sleep_timeout().	70	* @return See comment for waitq_sleep_timeout().
71	*/	71	*/
72	int _semaphore_down_timeout(semaphore_t *s, __u32 usec, int trydown)	72	int _semaphore_down_timeout(semaphore_t *s, __u32 usec, int trydown)
73	{	73	{
74	return waitq_sleep_timeout(&s->wq, usec, trydown);	74	return waitq_sleep_timeout(&s->wq, usec, trydown);
75	}	75	}
76		76
77	/** Semaphore up	77	/** Semaphore up
78	*	78	*
79	* Semaphore up.	79	* Semaphore up.
80	*	80	*
81	* @param s Semaphore.	81	* @param s Semaphore.
82	*/	82	*/
83	void semaphore_up(semaphore_t *s)	83	void semaphore_up(semaphore_t *s)
84	{	84	{
85	waitq_wakeup(&s->wq, WAKEUP_FIRST);	85	waitq_wakeup(&s->wq, WAKEUP_FIRST);
86	}	86	}
87		87

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/synch/semaphore.c – Rev 1229 → 1248