WebSVN – HelenOS – Diff – /trunk/kernel/generic/src/ddi/irq.c


/*
 * Copyright (c) 2006 Jakub Jermar
 * 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 genericddi
 * @{
 */
/**
 * @file
 * @brief   IRQ dispatcher.
 *
 * This file provides means of connecting IRQs with particular
 * devices and logic for dispatching interrupts to IRQ handlers
 * defined by those devices.
 *
 * This code is designed to support:
 * - multiple devices sharing single IRQ
 * - multiple IRQs per signle device
 *
 *
 * Note about architectures.
 *
 * Some architectures has the term IRQ well defined. Examples
 * of such architectures include amd64, ia32 and mips32. Some
 * other architectures, such as sparc64, don't use the term
 * at all. In those cases, we boldly step forward and define what
 * an IRQ is.
 *
 * The implementation is generic enough and still allows the
 * architectures to use the hardware layout effectively.
 * For instance, on amd64 and ia32, where there is only 16
 * IRQs, the irq_hash_table can be optimized to a one-dimensional
 * array. Next, when it is known that the IRQ numbers (aka INR's)
 * are unique, the claim functions can always return IRQ_ACCEPT.
 *
 *
 * Note about the irq_hash_table.
 *
 * The hash table is configured to use two keys: inr and devno.
 * However, the hash index is computed only from inr. Moreover,
 * if devno is -1, the match is based on the return value of
 * the claim() function instead of on devno.
 */
 
#include <ddi/irq.h>
#include <adt/hash_table.h>
#include <arch/types.h>
#include <typedefs.h>
#include <synch/spinlock.h>
#include <arch.h>
 
#define KEY_INR     0
#define KEY_DEVNO   1
 
/**
 * Spinlock protecting the hash table.
 * This lock must be taken only when interrupts are disabled.
 */
SPINLOCK_INITIALIZE(irq_hash_table_lock);
static hash_table_t irq_hash_table;
 
/**
 * Hash table operations for cases when we know that
 * there will be collisions between different keys.
 */
static index_t irq_ht_hash(unative_t *key);
static bool irq_ht_compare(unative_t *key, count_t keys, link_t *item);
 
static hash_table_operations_t irq_ht_ops = {
    .hash = irq_ht_hash,
    .compare = irq_ht_compare,
    .remove_callback = NULL     /* not used */
};
 
/**
 * Hash table operations for cases when we know that
 * there will be no collisions between different keys.
 * However, there might be still collisions among
 * elements with single key (sharing of one IRQ).
 */
static index_t irq_lin_hash(unative_t *key);
static bool irq_lin_compare(unative_t *key, count_t keys, link_t *item);
 
static hash_table_operations_t irq_lin_ops = {
    .hash = irq_lin_hash,
    .compare = irq_lin_compare,
    .remove_callback = NULL     /* not used */
};
 
/** Initialize IRQ subsystem.
 *
 * @param inrs Numbers of unique IRQ numbers or INRs.
 * @param chains Number of chains in the hash table.
 */
void irq_init(count_t inrs, count_t chains)
{
    /*
     * Be smart about the choice of the hash table operations.
     * In cases in which inrs equals the requested number of
     * chains (i.e. where there is no collision between
     * different keys), we can use optimized set of operations.
     */
    if (inrs == chains)
        hash_table_create(&irq_hash_table, chains, 2, &irq_lin_ops);
    else
        hash_table_create(&irq_hash_table, chains, 2, &irq_ht_ops);
}
 
/** Initialize one IRQ structure.
 *
 * @param irq Pointer to the IRQ structure to be initialized.
 *
 */
void irq_initialize(irq_t *irq)
{
    link_initialize(&irq->link);
    spinlock_initialize(&irq->lock, "irq.lock");
    irq->inr = -1;
    irq->devno = -1;
    irq->trigger = 0;
    irq->claim = NULL;
    irq->handler = NULL;
    irq->arg = NULL;
    irq->notif_cfg.notify = false;
    irq->notif_cfg.answerbox = NULL;
    irq->notif_cfg.code = NULL;
    irq->notif_cfg.method = 0;
    irq->notif_cfg.counter = 0;
    link_initialize(&irq->notif_cfg.link);
}
 
/** Register IRQ for device.
 *
 * The irq structure must be filled with information
 * about the interrupt source and with the claim()
 * function pointer and irq_handler() function pointer.
 *
 * @param irq IRQ structure belonging to a device.
 */
void irq_register(irq_t *irq)
{
    ipl_t ipl;
    unative_t key[] = {
        (unative_t) irq->inr,
        (unative_t) irq->devno
    };
   
    ipl = interrupts_disable();
    spinlock_lock(&irq_hash_table_lock);
    hash_table_insert(&irq_hash_table, key, &irq->link);
    spinlock_unlock(&irq_hash_table_lock);
    interrupts_restore(ipl);
}
 
/** Dispatch the IRQ.
 *
 * We assume this function is only called from interrupt
 * context (i.e. that interrupts are disabled prior to
 * this call).
 *
 * This function attempts to lookup a fitting IRQ
 * structure. In case of success, return with interrupts
 * disabled and holding the respective structure.
 *
 * @param inr Interrupt number (aka inr or irq).
 *
 * @return IRQ structure of the respective device or NULL.
 */
irq_t *irq_dispatch_and_lock(inr_t inr)
{
    link_t *lnk;
    unative_t key[] = {
        (unative_t) inr,
        (unative_t) -1      /* search will use claim() instead of devno */
    };
   
    spinlock_lock(&irq_hash_table_lock);
 
    lnk = hash_table_find(&irq_hash_table, key);
    if (lnk) {
        irq_t *irq;
       
        irq = hash_table_get_instance(lnk, irq_t, link);
 
        spinlock_unlock(&irq_hash_table_lock);
        return irq;
    }
   
    spinlock_unlock(&irq_hash_table_lock);
 
    return NULL;   
}
 
/** Find the IRQ structure corresponding to inr and devno.
 *
 * This functions attempts to lookup the IRQ structure
 * corresponding to its arguments. On success, this
 * function returns with interrups disabled, holding
 * the lock of the respective IRQ structure.
 *
 * This function assumes interrupts are already disabled.
 *
 * @param inr INR being looked up.
 * @param devno Devno being looked up.
 *
 * @return Locked IRQ structure on success or NULL on failure.
 */
irq_t *irq_find_and_lock(inr_t inr, devno_t devno)
{
    link_t *lnk;
    unative_t keys[] = {
        (unative_t) inr,
        (unative_t) devno
    };
   
    spinlock_lock(&irq_hash_table_lock);
 
    lnk = hash_table_find(&irq_hash_table, keys);
    if (lnk) {
        irq_t *irq;
       
        irq = hash_table_get_instance(lnk, irq_t, link);
 
        spinlock_unlock(&irq_hash_table_lock);
        return irq;
    }
   
    spinlock_unlock(&irq_hash_table_lock);
 
    return NULL;   
}
 
/** Compute hash index for the key.
 *
 * This function computes hash index into
 * the IRQ hash table for which there
 * can be collisions between different
 * INRs.
 *
 * The devno is not used to compute the hash.
 *
 * @param key The first of the keys is inr and the second is devno or -1.
 *
 * @return Index into the hash table.
 */
index_t irq_ht_hash(unative_t key[])
{
    inr_t inr = (inr_t) key[KEY_INR];
    return inr % irq_hash_table.entries;
}
 
/** Compare hash table element with a key.
 *
 * There are two things to note about this function.
 * First, it is used for the more complex architecture setup
 * in which there are way too many interrupt numbers (i.e. inr's)
 * to arrange the hash table so that collisions occur only
 * among same inrs of different devnos. So the explicit check
 * for inr match must be done.
 * Second, if devno is -1, the second key (i.e. devno) is not
 * used for the match and the result of the claim() function
 * is used instead.
 *
 * This function assumes interrupts are already disabled.
 *
 * @param key Keys (i.e. inr and devno).
 * @param keys This is 2.
 * @param item The item to compare the key with.
 *
 * @return True on match or false otherwise.
 */
bool irq_ht_compare(unative_t key[], count_t keys, link_t *item)
{
    irq_t *irq = hash_table_get_instance(item, irq_t, link);
    inr_t inr = (inr_t) key[KEY_INR];
    devno_t devno = (devno_t) key[KEY_DEVNO];
 
    bool rv;
   
    spinlock_lock(&irq->lock);
    if (devno == -1) {
        /* Invoked by irq_dispatch(). */
        rv = ((irq->inr == inr) && (irq->claim() == IRQ_ACCEPT));
    } else {
        /* Invoked by irq_find(). */
        rv = ((irq->inr == inr) && (irq->devno == devno));
    }
   
    /* unlock only on non-match */
    if (!rv)
        spinlock_unlock(&irq->lock);
 
    return rv;
}
 
/** Compute hash index for the key.
 *
 * This function computes hash index into
 * the IRQ hash table for which there
 * are no collisions between different
 * INRs.
 *
 * @param key The first of the keys is inr and the second is devno or -1.
 *
 * @return Index into the hash table.
 */
index_t irq_lin_hash(unative_t key[])
{
    inr_t inr = (inr_t) key[KEY_INR];
    return inr;
}
 
/** Compare hash table element with a key.
 *
 * There are two things to note about this function.
 * First, it is used for the less complex architecture setup
 * in which there are not too many interrupt numbers (i.e. inr's)
 * to arrange the hash table so that collisions occur only
 * among same inrs of different devnos. So the explicit check
 * for inr match is not done.
 * Second, if devno is -1, the second key (i.e. devno) is not
 * used for the match and the result of the claim() function
 * is used instead.
 *
 * This function assumes interrupts are already disabled.
 *
 * @param key Keys (i.e. inr and devno).
 * @param keys This is 2.
 * @param item The item to compare the key with.
 *
 * @return True on match or false otherwise.
 */
bool irq_lin_compare(unative_t key[], count_t keys, link_t *item)
{
    irq_t *irq = list_get_instance(item, irq_t, link);
    devno_t devno = (devno_t) key[KEY_DEVNO];
    bool rv;
   
    spinlock_lock(&irq->lock);
    if (devno == -1) {
        /* Invoked by irq_dispatch() */
        rv = (irq->claim() == IRQ_ACCEPT);
    } else {
        /* Invoked by irq_find() */
        rv = (irq->devno == devno);
    }
   
    /* unlock only on non-match */
    if (!rv)
        spinlock_unlock(&irq->lock);
   
    return rv;
}
 
/** @}
 */
 
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(root)/trunk/kernel/generic/src/ddi/irq.c – Rev 1933 → 2071
