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/*-
* Copyright (c) 2000 Michael Smith
* Copyright (c) 2000 BSDi
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*
* $FreeBSD$
*/
/*
* 6.1 : Mutual Exclusion and Synchronisation
*/
#include "acpi.h"
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
static MALLOC_DEFINE(M_ACPISEM, "acpisem", "ACPI semaphore");
/*
* Simple counting semaphore implemented using a mutex. (Subsequently used
* in the OSI code to implement a mutex. Go figure.)
*/
struct acpi_semaphore {
struct mtx as_mtx;
UINT32 as_units;
UINT32 as_maxunits;
};
ACPI_STATUS
AcpiOsCreateSemaphore(UINT32 MaxUnits, UINT32 InitialUnits, ACPI_HANDLE *OutHandle)
{
struct acpi_semaphore *as;
if (OutHandle == NULL)
return(AE_BAD_PARAMETER);
if (InitialUnits > MaxUnits)
return(AE_BAD_PARAMETER);
if ((as = malloc(sizeof(*as), M_ACPISEM, M_NOWAIT)) == NULL)
return(AE_NO_MEMORY);
mtx_init(&as->as_mtx, "ACPI semaphore", MTX_DEF);
as->as_units = InitialUnits;
as->as_maxunits = MaxUnits;
*OutHandle = (ACPI_HANDLE)as;
return(AE_OK);
}
ACPI_STATUS
AcpiOsDeleteSemaphore (ACPI_HANDLE Handle)
{
free(Handle, M_ACPISEM);
return(AE_OK);
}
/*
* This implementation has a bug, in that it has to stall for the entire
* timeout before it will return AE_TIME. A better implementation would
* use getmicrotime() to correctly adjust the timeout after being woken up.
*/
ACPI_STATUS
AcpiOsWaitSemaphore(ACPI_HANDLE Handle, UINT32 Units, UINT32 Timeout)
{
struct acpi_semaphore *as = (struct acpi_semaphore *)Handle;
int result;
if (as == NULL)
return(AE_BAD_PARAMETER);
mtx_enter(&as->as_mtx, MTX_DEF);
for (;;) {
if (as->as_units >= Units) {
as->as_units -= Units;
result = AE_OK;
break;
}
if (Timeout < 0) {
result = AE_TIME;
break;
}
if (msleep(as, &as->as_mtx, 0, "acpisem", Timeout / (1000 * hz)) == EWOULDBLOCK) {
result = AE_TIME;
break;
}
}
mtx_exit(&as->as_mtx, MTX_DEF);
return(result);
}
ACPI_STATUS
AcpiOsSignalSemaphore(ACPI_HANDLE Handle, UINT32 Units)
{
struct acpi_semaphore *as = (struct acpi_semaphore *)Handle;
if (as == NULL)
return(AE_BAD_PARAMETER);
mtx_enter(&as->as_mtx, MTX_DEF);
as->as_units += Units;
if (as->as_units > as->as_maxunits)
as->as_units = as->as_maxunits;
wakeup(as);
mtx_exit(&as->as_mtx, MTX_DEF);
return(AE_OK);
}
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