b60bd0c129
4-stable. -current uses a mutex for this purpose. Sponsored by: The Weather Channel
341 lines
9.0 KiB
C
341 lines
9.0 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 "opt_acpi.h"
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/sysctl.h>
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#if __FreeBSD_version >= 500000
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#endif
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#define _COMPONENT ACPI_OS_SERVICES
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ACPI_MODULE_NAME("SYNCH")
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static MALLOC_DEFINE(M_ACPISEM, "acpisem", "ACPI semaphore");
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#if __FreeBSD_version < 500000
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# define AS_LOCK(as) s = splhigh()
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# define AS_UNLOCK(as) splx(s)
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# define AS_LOCK_DECL int s
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# define msleep(a, b, c, d, e) tsleep(a, c, d, e)
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#else
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# define AS_LOCK(as) mtx_lock(&(as)->as_mtx)
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# define AS_UNLOCK(as) mtx_unlock(&(as)->as_mtx)
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# define AS_LOCK_DECL
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#endif
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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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#if __FreeBSD_version >= 500000
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struct mtx as_mtx;
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#endif
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UINT32 as_units;
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UINT32 as_maxunits;
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UINT32 as_pendings;
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UINT32 as_resetting;
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UINT32 as_timeouts;
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};
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#ifndef ACPI_NO_SEMAPHORES
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#ifndef ACPI_SEMAPHORES_MAX_PENDING
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#define ACPI_SEMAPHORES_MAX_PENDING 4
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#endif
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static int acpi_semaphore_debug = 0;
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TUNABLE_INT("debug.acpi_semaphore_debug", &acpi_semaphore_debug);
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SYSCTL_INT(_debug, OID_AUTO, acpi_semaphore_debug, CTLFLAG_RW,
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&acpi_semaphore_debug, 0, "");
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#endif
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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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#ifndef ACPI_NO_SEMAPHORES
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struct acpi_semaphore *as;
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ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
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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_ACPI_STATUS(AE_BAD_PARAMETER);
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if ((as = malloc(sizeof(*as), M_ACPISEM, M_NOWAIT)) == NULL)
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return_ACPI_STATUS(AE_NO_MEMORY);
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bzero(as, sizeof(*as));
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#if __FreeBSD_version >= 500000
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mtx_init(&as->as_mtx, "ACPI semaphore", NULL, MTX_DEF);
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#endif
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as->as_units = InitialUnits;
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as->as_maxunits = MaxUnits;
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as->as_pendings = as->as_resetting = as->as_timeouts = 0;
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ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
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"created semaphore %p max %d, initial %d\n",
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as, InitialUnits, MaxUnits));
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*OutHandle = (ACPI_HANDLE)as;
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return_ACPI_STATUS(AE_OK);
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#else
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*OutHandle = (ACPI_HANDLE)OutHandle;
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return(AE_OK);
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#endif
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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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#ifndef ACPI_NO_SEMAPHORES
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struct acpi_semaphore *as = (struct acpi_semaphore *)Handle;
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ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
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ACPI_DEBUG_PRINT((ACPI_DB_MUTEX, "destroyed semaphore %p\n", as));
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#if __FreeBSD_version >= 500000
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mtx_destroy(&as->as_mtx);
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#endif
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free(Handle, M_ACPISEM);
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return_ACPI_STATUS(AE_OK);
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#else
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return(AE_OK);
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#endif
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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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#ifndef ACPI_NO_SEMAPHORES
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struct acpi_semaphore *as = (struct acpi_semaphore *)Handle;
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ACPI_STATUS result;
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int rv, tmo;
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struct timeval timeouttv, currenttv, timelefttv;
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AS_LOCK_DECL;
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ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
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if (as == NULL)
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return_ACPI_STATUS(AE_BAD_PARAMETER);
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if (cold)
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return_ACPI_STATUS(AE_OK);
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#if 0
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if (as->as_units < Units && as->as_timeouts > 10) {
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printf("%s: semaphore %p too many timeouts, resetting\n", __func__, as);
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AS_LOCK(as);
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as->as_units = as->as_maxunits;
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if (as->as_pendings)
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as->as_resetting = 1;
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as->as_timeouts = 0;
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wakeup(as);
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AS_UNLOCK(as);
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return_ACPI_STATUS(AE_TIME);
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}
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if (as->as_resetting) {
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return_ACPI_STATUS(AE_TIME);
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}
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#endif
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/* a timeout of WAIT_FOREVER means "forever" */
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if (Timeout == WAIT_FOREVER) {
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tmo = 0;
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timeouttv.tv_sec = ((0xffff/1000) + 1); /* cf. ACPI spec */
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timeouttv.tv_usec = 0;
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} else {
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/* compute timeout using microseconds per tick */
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tmo = (Timeout * 1000) / (1000000 / hz);
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if (tmo <= 0)
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tmo = 1;
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timeouttv.tv_sec = Timeout / 1000;
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timeouttv.tv_usec = (Timeout % 1000) * 1000;
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}
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/* calculate timeout value in timeval */
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getmicrotime(¤ttv);
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timevaladd(&timeouttv, ¤ttv);
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AS_LOCK(as);
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ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
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"get %d units from semaphore %p (has %d), timeout %d\n",
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Units, as, as->as_units, Timeout));
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for (;;) {
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if (as->as_maxunits == ACPI_NO_UNIT_LIMIT) {
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result = AE_OK;
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break;
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}
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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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/* limit number of pending treads */
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if (as->as_pendings >= ACPI_SEMAPHORES_MAX_PENDING) {
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result = AE_TIME;
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break;
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}
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/* if timeout values of zero is specified, return immediately */
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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 __FreeBSD_version >= 500000
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ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
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"semaphore blocked, calling msleep(%p, %p, %d, \"acsem\", %d)\n",
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as, &as->as_mtx, PCATCH, tmo));
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#endif
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as->as_pendings++;
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if (acpi_semaphore_debug) {
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printf("%s: Sleep %d, pending %d, semaphore %p, thread %d\n",
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__func__, Timeout, as->as_pendings, as, AcpiOsGetThreadId());
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}
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rv = msleep(as, &as->as_mtx, PCATCH, "acsem", tmo);
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as->as_pendings--;
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#if 0
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if (as->as_resetting) {
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/* semaphore reset, return immediately */
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if (as->as_pendings == 0) {
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as->as_resetting = 0;
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}
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result = AE_TIME;
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break;
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}
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#endif
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ACPI_DEBUG_PRINT((ACPI_DB_MUTEX, "msleep(%d) returned %d\n", tmo, rv));
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if (rv == EWOULDBLOCK) {
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result = AE_TIME;
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break;
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}
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/* check if we already awaited enough */
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timelefttv = timeouttv;
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getmicrotime(¤ttv);
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timevalsub(&timelefttv, ¤ttv);
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if (timelefttv.tv_sec < 0) {
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ACPI_DEBUG_PRINT((ACPI_DB_MUTEX, "await semaphore %p timeout\n", as));
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result = AE_TIME;
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break;
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}
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/* adjust timeout for the next sleep */
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tmo = (timelefttv.tv_sec * 1000000 + timelefttv.tv_usec) / (1000000 / hz);
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if (tmo <= 0)
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tmo = 1;
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if (acpi_semaphore_debug) {
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printf("%s: Wakeup timeleft(%lu, %lu), tmo %u, semaphore %p, thread %d\n",
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__func__, timelefttv.tv_sec, timelefttv.tv_usec, tmo, as, AcpiOsGetThreadId());
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}
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}
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if (acpi_semaphore_debug) {
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if (result == AE_TIME && Timeout > 0) {
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printf("%s: Timeout %d, pending %d, semaphore %p\n",
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__func__, Timeout, as->as_pendings, as);
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}
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if (result == AE_OK && (as->as_timeouts > 0 || as->as_pendings > 0)) {
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printf("%s: Acquire %d, units %d, pending %d, semaphore %p, thread %d\n",
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__func__, Units, as->as_units, as->as_pendings, as, AcpiOsGetThreadId());
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}
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}
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if (result == AE_TIME) {
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as->as_timeouts++;
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} else {
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as->as_timeouts = 0;
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}
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AS_UNLOCK(as);
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return_ACPI_STATUS(result);
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#else
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return(AE_OK);
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#endif
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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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#ifndef ACPI_NO_SEMAPHORES
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struct acpi_semaphore *as = (struct acpi_semaphore *)Handle;
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AS_LOCK_DECL;
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ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
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if (as == NULL)
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return_ACPI_STATUS(AE_BAD_PARAMETER);
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AS_LOCK(as);
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ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
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"return %d units to semaphore %p (has %d)\n",
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Units, as, as->as_units));
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if (as->as_maxunits != ACPI_NO_UNIT_LIMIT) {
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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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}
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if (acpi_semaphore_debug && (as->as_timeouts > 0 || as->as_pendings > 0)) {
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printf("%s: Release %d, units %d, pending %d, semaphore %p, thread %d\n",
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__func__, Units, as->as_units, as->as_pendings, as, AcpiOsGetThreadId());
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}
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wakeup(as);
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AS_UNLOCK(as);
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return_ACPI_STATUS(AE_OK);
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#else
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return(AE_OK);
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#endif
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}
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