OsdSynch.c revision 67760 
1/*-
2 * Copyright (c) 2000 Michael Smith
3 * Copyright (c) 2000 BSDi
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 *	$FreeBSD: head/sys/dev/acpica/Osd/OsdSynch.c 67760 2000-10-28 06:56:15Z msmith $
28 */
29
30/*
31 * 6.1 : Mutual Exclusion and Synchronisation
32 */
33
34#include "acpi.h"
35
36#include <sys/kernel.h>
37#include <sys/malloc.h>
38#include <sys/mutex.h>
39
40MALLOC_DEFINE(M_ACPISEM, "acpisem", "ACPI semaphore");
41
42/*
43 * Simple counting semaphore implemented using a mutex. (Subsequently used
44 * in the OSI code to implement a mutex.  Go figure.)
45 */
46struct acpi_semaphore {
47    struct mtx	as_mtx;
48    UINT32	as_units;
49    UINT32	as_maxunits;
50};
51
52ACPI_STATUS
53AcpiOsCreateSemaphore(UINT32 MaxUnits, UINT32 InitialUnits, ACPI_HANDLE *OutHandle)
54{
55    struct acpi_semaphore	*as;
56
57    if (OutHandle == NULL)
58	return(AE_BAD_PARAMETER);
59    if (InitialUnits > MaxUnits)
60	return(AE_BAD_PARAMETER);
61
62    if ((as = malloc(sizeof(*as), M_ACPISEM, M_NOWAIT)) == NULL)
63	return(AE_NO_MEMORY);
64
65    mtx_init(&as->as_mtx, "ACPI semaphore", MTX_DEF);
66    as->as_units = InitialUnits;
67    as->as_maxunits = MaxUnits;
68
69    *OutHandle = (ACPI_HANDLE)as;
70    return(AE_OK);
71}
72
73ACPI_STATUS
74AcpiOsDeleteSemaphore (ACPI_HANDLE Handle)
75{
76    free(Handle, M_ACPISEM);
77    return(AE_OK);
78}
79
80/*
81 * This implementation has a bug, in that it has to stall for the entire
82 * timeout before it will return AE_TIME.  A better implementation would
83 * use getmicrotime() to correctly adjust the timeout after being woken up.
84 */
85ACPI_STATUS
86AcpiOsWaitSemaphore(ACPI_HANDLE Handle, UINT32 Units, UINT32 Timeout)
87{
88    struct acpi_semaphore	*as = (struct acpi_semaphore *)Handle;
89    int				result;
90
91    if (as == NULL)
92	return(AE_BAD_PARAMETER);
93
94    mtx_enter(&as->as_mtx, MTX_DEF);
95    for (;;) {
96	if (as->as_units >= Units) {
97	    as->as_units -= Units;
98	    result = AE_OK;
99	    break;
100	}
101	if (Timeout < 0) {
102	    result = AE_TIME;
103	    break;
104	}
105	if (msleep(as, &as->as_mtx, 0, "acpisem", Timeout / (1000 * hz)) == EWOULDBLOCK) {
106	    result = AE_TIME;
107	    break;
108	}
109    }
110    mtx_exit(&as->as_mtx, MTX_DEF);
111
112    return(result);
113}
114
115ACPI_STATUS
116AcpiOsSignalSemaphore(ACPI_HANDLE Handle, UINT32 Units)
117{
118    struct acpi_semaphore	*as = (struct acpi_semaphore *)Handle;
119
120    if (as == NULL)
121	return(AE_BAD_PARAMETER);
122
123    mtx_enter(&as->as_mtx, MTX_DEF);
124    as->as_units += Units;
125    if (as->as_units > as->as_maxunits)
126	as->as_units = as->as_maxunits;
127    wakeup(as);
128    mtx_exit(&as->as_mtx, MTX_DEF);
129
130    return(AE_OK);
131}
132