134 lines
3.7 KiB
C
134 lines
3.7 KiB
C
/*-
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* Copyright (c) 2000 Michael Smith
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* Copyright (c) 2000 BSDi
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* 6.1 : Mutual Exclusion and Synchronisation
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*/
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#include "acpi.h"
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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static MALLOC_DEFINE(M_ACPISEM, "acpisem", "ACPI semaphore");
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/*
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* Simple counting semaphore implemented using a mutex. (Subsequently used
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* in the OSI code to implement a mutex. Go figure.)
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*/
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struct acpi_semaphore {
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struct mtx as_mtx;
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UINT32 as_units;
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UINT32 as_maxunits;
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};
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ACPI_STATUS
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AcpiOsCreateSemaphore(UINT32 MaxUnits, UINT32 InitialUnits, ACPI_HANDLE *OutHandle)
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{
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struct acpi_semaphore *as;
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if (OutHandle == NULL)
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return(AE_BAD_PARAMETER);
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if (InitialUnits > MaxUnits)
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return(AE_BAD_PARAMETER);
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if ((as = malloc(sizeof(*as), M_ACPISEM, M_NOWAIT)) == NULL)
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return(AE_NO_MEMORY);
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mtx_init(&as->as_mtx, "ACPI semaphore", MTX_DEF);
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as->as_units = InitialUnits;
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as->as_maxunits = MaxUnits;
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*OutHandle = (ACPI_HANDLE)as;
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return(AE_OK);
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}
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ACPI_STATUS
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AcpiOsDeleteSemaphore (ACPI_HANDLE Handle)
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{
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struct acpi_semaphore *as = (struct acpi_semaphore *)Handle;
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mtx_destroy(&as->as_mtx);
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free(Handle, M_ACPISEM);
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return(AE_OK);
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}
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/*
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* This implementation has a bug, in that it has to stall for the entire
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* timeout before it will return AE_TIME. A better implementation would
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* use getmicrotime() to correctly adjust the timeout after being woken up.
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*/
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ACPI_STATUS
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AcpiOsWaitSemaphore(ACPI_HANDLE Handle, UINT32 Units, UINT32 Timeout)
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{
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struct acpi_semaphore *as = (struct acpi_semaphore *)Handle;
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int result;
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if (as == NULL)
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return(AE_BAD_PARAMETER);
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mtx_enter(&as->as_mtx, MTX_DEF);
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for (;;) {
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if (as->as_units >= Units) {
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as->as_units -= Units;
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result = AE_OK;
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break;
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}
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if (Timeout < 0) {
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result = AE_TIME;
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break;
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}
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if (msleep(as, &as->as_mtx, 0, "acpisem", Timeout / (1000 * hz)) == EWOULDBLOCK) {
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result = AE_TIME;
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break;
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}
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}
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mtx_exit(&as->as_mtx, MTX_DEF);
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return(result);
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}
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ACPI_STATUS
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AcpiOsSignalSemaphore(ACPI_HANDLE Handle, UINT32 Units)
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{
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struct acpi_semaphore *as = (struct acpi_semaphore *)Handle;
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if (as == NULL)
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return(AE_BAD_PARAMETER);
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mtx_enter(&as->as_mtx, MTX_DEF);
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as->as_units += Units;
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if (as->as_units > as->as_maxunits)
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as->as_units = as->as_maxunits;
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wakeup(as);
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mtx_exit(&as->as_mtx, MTX_DEF);
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return(AE_OK);
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}
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