Subversion Repositories HelenOS

/*

 * Copyright (c) 2006 Ondrej Palkovsky

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - 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.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.

 */

/** @addtogroup libc

 * @{

 */

/** @file

 */

#include <sys/time.h>

#include <unistd.h>

#include <ipc/ipc.h>

#include <stdio.h>

#include <arch/barrier.h>

#include <unistd.h>

#include <atomic.h>

#include <futex.h>

#include <sysinfo.h>

#include <ipc/services.h>

#include <sysinfo.h>

#include <as.h>

#include <ddi.h>

/* Pointers to public variables with time */

struct {

    volatile sysarg_t seconds1;

    volatile sysarg_t useconds;

    volatile sysarg_t seconds2;

} *ktime = NULL;

/** Add microseconds to given timeval.

 *

 * @param tv        Destination timeval.

 * @param usecs     Number of microseconds to add.

 */

void tv_add(struct timeval *tv, suseconds_t usecs)

{

    tv->tv_sec += usecs / 1000000;

    tv->tv_usec += usecs % 1000000;

    if (tv->tv_usec > 1000000) {

        tv->tv_sec++;

        tv->tv_usec -= 1000000;

    }

}

/** Subtract two timevals.

 *

 * @param tv1       First timeval.

 * @param tv2       Second timeval.

 *

 * @return      Return difference between tv1 and tv2 (tv1 - tv2) in

 *          microseconds.

 */

suseconds_t tv_sub(struct timeval *tv1, struct timeval *tv2)

{

    suseconds_t result;

    result = tv1->tv_usec - tv2->tv_usec;

    result += (tv1->tv_sec - tv2->tv_sec) * 1000000;

    return result;

}

/** Decide if one timeval is greater than the other.

 *

 * @param t1        First timeval.

 * @param t2        Second timeval.

 *

 * @return      Return true tv1 is greater than tv2. Otherwise return

 *          false.

 */

int tv_gt(struct timeval *tv1, struct timeval *tv2)

{

    if (tv1->tv_sec > tv2->tv_sec)

        return 1;

    if (tv1->tv_sec == tv2->tv_sec && tv1->tv_usec > tv2->tv_usec)

        return 1;

    return 0;

}

/** Decide if one timeval is greater than or equal to the other.

 *

 * @param tv1       First timeval.

 * @param tv2       Second timeval.

 *

 * @return      Return true if tv1 is greater than or equal to tv2.

 *          Otherwise return false.

 */

int tv_gteq(struct timeval *tv1, struct timeval *tv2)

{

    if (tv1->tv_sec > tv2->tv_sec)

        return 1;

    if (tv1->tv_sec == tv2->tv_sec && tv1->tv_usec >= tv2->tv_usec)

        return 1;

    return 0;

}

/** POSIX gettimeofday

 *

 * The time variables are memory mapped(RO) from kernel, which updates

 * them periodically. As it is impossible to read 2 values atomically, we

 * use a trick: First read a seconds, then read microseconds, then

 * read seconds again. If a second elapsed in the meantime, set it to zero.

 * This provides assurance, that at least the

 * sequence of subsequent gettimeofday calls is ordered.

 */

int gettimeofday(struct timeval *tv, struct timezone *tz)

{

    void *mapping;

    sysarg_t s1, s2;

    sysarg_t rights;

    int res;

    if (!ktime) {

        mapping = as_get_mappable_page(PAGE_SIZE);

        /* Get the mapping of kernel clock */

        res = ipc_call_sync_3(PHONE_NS, IPC_M_AS_AREA_RECV,

            (sysarg_t) mapping, PAGE_SIZE, SERVICE_MEM_REALTIME, NULL,

            &rights, NULL);

        if (res) {

            printf("Failed to initialize timeofday memarea\n");

            _exit(1);

        }

        if (! (rights & AS_AREA_READ)) {

            printf("Received bad rights on time area: %X\n",

                   rights);

            as_area_destroy(mapping);

            _exit(1);

        }

        ktime = mapping;

    }

    if (tz) {

        tz->tz_minuteswest = 0;

        tz->tz_dsttime = DST_NONE;

    }

    s2 = ktime->seconds2;

    read_barrier();

    tv->tv_usec = ktime->useconds;

    read_barrier();

    s1 = ktime->seconds1;

    if (s1 != s2) {

        tv->tv_usec = 0;

        tv->tv_sec = s1 > s2 ? s1 : s2;

    } else

        tv->tv_sec = s1;

    return 0;

}

/** Wait unconditionally for specified number of microseconds */

void usleep(unsigned long usec)

{

    atomic_t futex = FUTEX_INITIALIZER;

    futex_initialize(&futex, 0);

    futex_down_timeout(&futex, usec, 0);

}

/** Wait unconditionally for specified number of seconds */

unsigned int sleep(unsigned int seconds)

{

    atomic_t futex = FUTEX_INITIALIZER;

    futex_initialize(&futex, 0);

    /* Sleep in 1000 second steps to support

       full argument range */

    while (seconds > 0) {

        unsigned int period = (seconds > 1000) ? 1000 : seconds;

        futex_down_timeout(&futex, period * 1000000, 0);

        seconds -= period;

    }

}

/** @}

 */