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1 jermar 1
/*
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 * Copyright (C) 2001-2004 Jakub Jermar
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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/timeout.h>
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#include <typedefs.h>
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#include <arch/types.h>
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#include <config.h>
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#include <synch/spinlock.h>
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#include <func.h>
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#include <cpu.h>
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#include <print.h>
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#include <arch/asm.h>
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#include <arch.h>
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void timeout_init(void)
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{
15 jermar 42
    spinlock_initialize(&CPU->timeoutlock);
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    list_initialize(&CPU->timeout_active_head);
1 jermar 44
}
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void timeout_reinitialize(timeout_t *t)
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{
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    t->cpu = NULL;
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    t->ticks = 0;
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    t->handler = NULL;
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    t->arg = NULL;
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    link_initialize(&t->link);
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}
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void timeout_initialize(timeout_t *t)
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{
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    spinlock_initialize(&t->lock);
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    timeout_reinitialize(t);
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}
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/*
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 * This function registers f for execution in about time microseconds.
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 */
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void timeout_register(timeout_t *t, __u64 time, timeout_handler f, void *arg)
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{
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    timeout_t *hlp;
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    link_t *l, *m;
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    pri_t pri;
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    __u64 sum;
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    pri = cpu_priority_high();
15 jermar 73
    spinlock_lock(&CPU->timeoutlock);
1 jermar 74
    spinlock_lock(&t->lock);
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    if (t->cpu)
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        panic("timeout_register: t->cpu != 0");
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15 jermar 79
    t->cpu = CPU;
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    t->ticks = us2ticks(time);
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    t->handler = f;
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    t->arg = arg;
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    /*
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     * Insert t into the active timeouts list according to t->ticks.
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     */
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    sum = 0;
15 jermar 89
    l = CPU->timeout_active_head.next;
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    while (l != &CPU->timeout_active_head) {
1 jermar 91
        hlp = list_get_instance(l, timeout_t, link);
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        spinlock_lock(&hlp->lock);
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        if (t->ticks < sum + hlp->ticks) {
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            spinlock_unlock(&hlp->lock);
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            break;
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        }
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        sum += hlp->ticks;
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        spinlock_unlock(&hlp->lock);
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        l = l->next;
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    }
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    m = l->prev;
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    list_prepend(&t->link, m); /* avoid using l->prev */
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    /*
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     * Adjust t->ticks according to ticks accumulated in h's predecessors.
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     */
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    t->ticks -= sum;
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    /*
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     * Decrease ticks of t's immediate succesor by t->ticks.
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     */
15 jermar 112
    if (l != &CPU->timeout_active_head) {
1 jermar 113
        spinlock_lock(&hlp->lock);
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        hlp->ticks -= t->ticks;
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        spinlock_unlock(&hlp->lock);
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    }
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    spinlock_unlock(&t->lock);
15 jermar 119
    spinlock_unlock(&CPU->timeoutlock);
1 jermar 120
    cpu_priority_restore(pri);
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}
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int timeout_unregister(timeout_t *t)
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{
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    timeout_t *hlp;
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    link_t *l;
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    pri_t pri;
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grab_locks:
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    pri = cpu_priority_high();
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    spinlock_lock(&t->lock);
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    if (!t->cpu) {
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        spinlock_unlock(&t->lock);
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        cpu_priority_restore(pri);
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        return 0;
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    }
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    if (!spinlock_trylock(&t->cpu->timeoutlock)) {
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        spinlock_unlock(&t->lock);
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        cpu_priority_restore(pri);     
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        goto grab_locks;
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    }
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    /*
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     * Now we know for sure that t hasn't been activated yet
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     * and is lurking in t->cpu->timeout_active_head queue.
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     */
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    l = t->link.next;
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    if (l != &t->cpu->timeout_active_head) {
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        hlp = list_get_instance(l, timeout_t, link);
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        spinlock_lock(&hlp->lock);
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        hlp->ticks += t->ticks;
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        spinlock_unlock(&hlp->lock);
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    }
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    list_remove(&t->link);
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    spinlock_unlock(&t->cpu->timeoutlock);
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    timeout_reinitialize(t);
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    spinlock_unlock(&t->lock);
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    cpu_priority_restore(pri);
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    return 1;
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}