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1435 palkovsky 1
/*
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 * Copyright (C) 2006 Ondrej Palkovsky
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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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 *
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 * - 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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 * - 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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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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#include <time.h>
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#include <unistd.h>
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#include <ipc/ipc.h>
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#include <stdio.h>
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#include <arch/barrier.h>
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#include <sysinfo.h>
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#include <as.h>
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#include <ddi.h>
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/* Pointers to public variables with time */
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struct {
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    volatile sysarg_t seconds1;
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    volatile sysarg_t useconds;
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    volatile sysarg_t seconds2;
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} *ktime = NULL;
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/** POSIX gettimeofday
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 *
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 * The time variables are memory mapped(RO) from kernel, which updates
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 * them periodically. As it is impossible to read 2 values atomically, we
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 * use a trick: First read a seconds, then read microseconds, then
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 * read seconds again. If a second elapsed in the meantime, read
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 * useconds again. This provides assurance, that at least the
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 * sequence of subsequent gettimeofday calls is ordered.
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 */
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#define TMAREA (100*1024*1024)
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int gettimeofday(struct timeval *tv, struct timezone *tz)
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{
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    void *mapping;
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    sysarg_t s1, s2;
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    sysarg_t t1;
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    int res;
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    if (!ktime) {
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        /* TODO: specify better, where to map the area */
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        /* Get the mapping of kernel clock */
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        res = ipc_call_sync_3(PHONE_NS, IPC_M_AS_AREA_RECV,
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                      TMAREA,
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                      PAGE_SIZE,
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                      AS_AREA_READ | AS_AREA_CACHEABLE,
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                      &t1,&t1,&t1);
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        if (res) {
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            printf("Failed to initialize timeofday memarea\n");
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            _exit(1);
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        }
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        ktime = (void *) (TMAREA);
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    }
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    if (tz) {
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        tz->tz_minuteswest = 0;
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        tz->tz_dsttime = DST_NONE;
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    }
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    s2 = ktime->seconds2;
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    read_barrier();
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    tv->tv_usec = ktime->useconds;
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    read_barrier();
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    s1 = ktime->seconds1;
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    if (s1 != s2) {
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        tv->tv_usec = 0;
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        tv->tv_sec = s1 > s2 ? s1 : s2;
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    } else
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        tv->tv_sec = s1;
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    return 0;
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}