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 * $FreeBSD$ 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/lock.h> 38 #include <sys/malloc.h> 39 #include <sys/mutex.h> 40 41 #define _COMPONENT ACPI_OS_SERVICES 42 MODULE_NAME("SYNCH") 43 44 static MALLOC_DEFINE(M_ACPISEM, "acpisem", "ACPI semaphore"); 45 46 /* disable semaphores - AML in the field doesn't use them correctly */ 47 #define ACPI_NO_SEMAPHORES 48 49 /* 50 * Simple counting semaphore implemented using a mutex. (Subsequently used 51 * in the OSI code to implement a mutex. Go figure.) 52 */ 53 struct acpi_semaphore { 54 struct mtx as_mtx; 55 UINT32 as_units; 56 UINT32 as_maxunits; 57 }; 58 59 ACPI_STATUS 60 AcpiOsCreateSemaphore(UINT32 MaxUnits, UINT32 InitialUnits, ACPI_HANDLE *OutHandle) 61 { 62 #ifndef ACPI_NO_SEMAPHORES 63 struct acpi_semaphore *as; 64 65 FUNCTION_TRACE(__func__); 66 67 if (OutHandle == NULL) 68 return(AE_BAD_PARAMETER); 69 if (InitialUnits > MaxUnits) 70 return_ACPI_STATUS(AE_BAD_PARAMETER); 71 72 if ((as = malloc(sizeof(*as), M_ACPISEM, M_NOWAIT)) == NULL) 73 return_ACPI_STATUS(AE_NO_MEMORY); 74 75 mtx_init(&as->as_mtx, "ACPI semaphore", MTX_DEF); 76 as->as_units = InitialUnits; 77 as->as_maxunits = MaxUnits; 78 79 DEBUG_PRINT(TRACE_MUTEX, ("created semaphore %p max %d, initial %d\n", 80 as, InitialUnits, MaxUnits)); 81 82 *OutHandle = (ACPI_HANDLE)as; 83 return_ACPI_STATUS(AE_OK); 84 #else 85 *OutHandle = (ACPI_HANDLE)OutHandle; 86 return(AE_OK); 87 #endif 88 } 89 90 ACPI_STATUS 91 AcpiOsDeleteSemaphore (ACPI_HANDLE Handle) 92 { 93 #ifndef ACPI_NO_SEMAPHORES 94 struct acpi_semaphore *as = (struct acpi_semaphore *)Handle; 95 96 FUNCTION_TRACE(__func__); 97 98 DEBUG_PRINT(TRACE_MUTEX, ("destroyed semaphore %p\n", as)); 99 mtx_destroy(&as->as_mtx); 100 free(Handle, M_ACPISEM); 101 return_ACPI_STATUS(AE_OK); 102 #else 103 return(AE_OK); 104 #endif 105 } 106 107 /* 108 * This implementation has a bug, in that it has to stall for the entire 109 * timeout before it will return AE_TIME. A better implementation would 110 * use getmicrotime() to correctly adjust the timeout after being woken up. 111 */ 112 ACPI_STATUS 113 AcpiOsWaitSemaphore(ACPI_HANDLE Handle, UINT32 Units, UINT32 Timeout) 114 { 115 #ifndef ACPI_NO_SEMAPHORES 116 struct acpi_semaphore *as = (struct acpi_semaphore *)Handle; 117 ACPI_STATUS result; 118 int rv, tmo; 119 120 FUNCTION_TRACE(__func__); 121 122 if (as == NULL) 123 return_ACPI_STATUS(AE_BAD_PARAMETER); 124 125 /* a timeout of -1 means "forever" */ 126 if (Timeout == -1) { 127 tmo = 0; 128 } else { 129 /* compute timeout using microseconds per tick */ 130 tmo = (Timeout * 1000) / (1000000 / hz); 131 if (tmo <= 0) 132 tmo = 1; 133 } 134 135 mtx_lock(&as->as_mtx); 136 DEBUG_PRINT(TRACE_MUTEX, ("get %d units from semaphore %p (has %d), timeout %d\n", 137 Units, as, as->as_units, Timeout)); 138 for (;;) { 139 if (as->as_inits == ACPI_NO_UNIT_LIMIT) { 140 result = AE_OK; 141 break; 142 } 143 if (as->as_units >= Units) { 144 as->as_units -= Units; 145 result = AE_OK; 146 break; 147 } 148 if (Timeout < 0) { 149 result = AE_TIME; 150 break; 151 } 152 DEBUG_PRINT(TRACE_MUTEX, ("semaphore blocked, calling msleep(%p, %p, %d, \"acpisem\", %d)\n", 153 as, as->as_mtx, 0, tmo)); 154 155 rv = msleep(as, &as->as_mtx, 0, "acpisem", tmo); 156 DEBUG_PRINT(TRACE_MUTEX, ("msleep returned %d\n", rv)); 157 if (rv == EWOULDBLOCK) { 158 result = AE_TIME; 159 break; 160 } 161 } 162 mtx_unlock(&as->as_mtx); 163 164 return_ACPI_STATUS(result); 165 #else 166 return(AE_OK); 167 #endif 168 } 169 170 ACPI_STATUS 171 AcpiOsSignalSemaphore(ACPI_HANDLE Handle, UINT32 Units) 172 { 173 #ifndef ACPI_NO_SEMAPHORES 174 struct acpi_semaphore *as = (struct acpi_semaphore *)Handle; 175 176 FUNCTION_TRACE(__func__); 177 178 if (as == NULL) 179 return_ACPI_STATUS(AE_BAD_PARAMETER); 180 181 mtx_lock(&as->as_mtx); 182 DEBUG_PRINT(TRACE_MUTEX, ("return %d units to semaphore %p (has %d)\n", 183 Units, as, as->as_units)); 184 if (as->as_units != ACPI_NO_UNIT_LIMIT) { 185 as->as_units += Units; 186 if (as->as_units > as->as_maxunits) 187 as->as_units = as->as_maxunits; 188 } 189 wakeup(as); 190 mtx_unlock(&as->as_mtx); 191 return_ACPI_STATUS(AE_OK); 192 #else 193 return(AE_OK); 194 #endif 195 } 196