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/*
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/*
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 * Copyright (C) 2005 Martin Decky
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 * Copyright (C) 2005 Martin Decky
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 * Copyright (C) 2005 Jakub Jermar
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 * All rights reserved.
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 * All rights reserved.
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 *
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 *
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 * Redistribution and use in source and binary forms, with or without
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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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 * modification, are permitted provided that the following conditions
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 * are met:
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 * are met:
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 *
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 *
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 * - Redistributions of source code must retain the above copyright
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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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 *   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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 * - 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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 *   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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 *   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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 * - 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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 *   derived from this software without specific prior written permission.
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 *
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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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 * 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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 * 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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 * 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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 * 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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 * 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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 * 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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 * 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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 * 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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 * (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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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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 */
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#include <arch/mm/asid.h>
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#include <arch/mm/asid.h>
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#include <synch/spinlock.h>
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#include <synch/spinlock.h>
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#include <arch.h>
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#include <arch.h>
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#include <debug.h>
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#include <debug.h>
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#define ASIDS   256
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#include <typedefs.h>
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static spinlock_t asid_usage_lock;
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static spinlock_t asid_usage_lock;
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static count_t asid_usage[ASIDS];   /**< Usage tracking array for ASIDs */
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static count_t asid_usage[ASIDS];   /**< Usage tracking array for ASIDs */
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/** Get ASID
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/** Get ASID
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 *
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 *
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 * Get the least used ASID.
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 * Get the least used ASID.
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 *
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 *
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 * @return ASID
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 * @return ASID
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 */
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 */
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asid_t asid_get(void)
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asid_t asid_get(void)
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{
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{
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    pri_t pri;
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    pri_t pri;
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    int i, j;
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    int i, j;
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    count_t min;
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    count_t min;
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    min = (unsigned) -1;
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    min = (unsigned) -1;
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    pri = cpu_priority_high();
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    pri = cpu_priority_high();
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    spinlock_lock(&asid_usage_lock);
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    spinlock_lock(&asid_usage_lock);
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    for (i=0, j = 0; (i<ASIDS); i++) {
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    for (i = ASID_START, j = ASID_START; i < ASIDS; i++) {
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        if (asid_usage[i] < min) {
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        if (asid_usage[i] < min) {
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            j = i;
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            j = i;
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            min = asid_usage[i];
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            min = asid_usage[i];
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            if (!min)
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            if (!min)
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                break;
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                break;
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        }
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        }
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    }
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    }
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    asid_usage[i]++;
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    asid_usage[j]++;
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    spinlock_unlock(&asid_usage_lock);
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    spinlock_unlock(&asid_usage_lock);
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    cpu_priority_restore(pri);
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    cpu_priority_restore(pri);
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    return i;
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    return i;
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}
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}
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/** Release ASID
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/** Release ASID
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 *
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 *
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 * Release ASID by decrementing its usage count.
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 * Release ASID by decrementing its usage count.
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 *
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 *
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 * @param asid ASID.
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 * @param asid ASID.
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 */
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 */
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void asid_put(asid_t asid)
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void asid_put(asid_t asid)
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{
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{
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    pri_t pri;
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    pri_t pri;
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    pri = cpu_priority_high();
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    pri = cpu_priority_high();
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    spinlock_lock(&asid_usage_lock);
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    spinlock_lock(&asid_usage_lock);
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    ASSERT(asid != ASID_INVALID);
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    ASSERT(asid_usage[asid] > 0);
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    ASSERT(asid_usage[asid] > 0);
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    asid_usage[asid]--;
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    asid_usage[asid]--;
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    spinlock_unlock(&asid_usage_lock);
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    spinlock_unlock(&asid_usage_lock);
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    cpu_priority_restore(pri);
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    cpu_priority_restore(pri);
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}
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}
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/** Find out whether ASID is used by more address spaces
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 *
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 * Find out whether ASID is used by more address spaces.
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 *
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 * @param asid ASID in question.
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 *
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 * @return True if 'asid' is used by more address spaces, false otherwise.
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 */
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bool asid_has_conflicts(asid_t asid)
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{
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    bool has_conflicts = false;
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    pri_t pri;
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    ASSERT(asid != ASID_INVALID);
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    pri = cpu_priority_high();
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    spinlock_lock(&asid_usage_lock);
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    if (asid_usage[asid] > 1)
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        has_conflicts = true;
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    spinlock_unlock(&asid_usage_lock);
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    cpu_priority_restore(pri);
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    return has_conflicts;
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}
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