/*
* 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 single device
* - multiple instances of the same 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 <mm/slab.h>
#include <arch/types.h>
#include <synch/spinlock.h>
#include <memstr.h>
#include <arch.h>
#define KEY_INR 0
#define KEY_DEVNO 1
/**
* Spinlock protecting the kernel IRQ hash table.
* This lock must be taken only when interrupts are disabled.
*/
SPINLOCK_INITIALIZE(irq_kernel_hash_table_lock);
/** The kernel IRQ hash table. */
static hash_table_t irq_kernel_hash_table;
/**
* Spinlock protecting the uspace IRQ hash table.
* This lock must be taken only when interrupts are disabled.
*/
SPINLOCK_INITIALIZE(irq_uspace_hash_table_lock);
/** The uspace IRQ hash table. */
hash_table_t irq_uspace_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 */
};
/** Number of buckets in either of the hash tables. */
static count_t buckets;
/** 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)
{
buckets = 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_uspace_hash_table, chains, 2,
&irq_lin_ops);
hash_table_create(&irq_kernel_hash_table, chains, 2,
&irq_lin_ops);
} else {
hash_table_create(&irq_uspace_hash_table, chains, 2,
&irq_ht_ops);
hash_table_create(&irq_kernel_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)
{
memsetb(irq, 0, sizeof(irq_t));
link_initialize(&irq->link);
spinlock_initialize(&irq->lock, "irq.lock");
link_initialize(&irq->notif_cfg.link);
irq->inr = -1;
irq->devno = -1;
}
/** Register IRQ for device.
*
* The irq structure must be filled with information
* about the interrupt source and with the claim()
* function pointer and handler() function pointer.
*
* @param irq IRQ structure belonging to a device.
* @return True on success, false on failure.
*/
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_kernel_hash_table_lock);
spinlock_lock(&irq->lock);
hash_table_insert(&irq_kernel_hash_table, key, &irq->link);
spinlock_unlock(&irq->lock);
spinlock_unlock(&irq_kernel_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 */
};
/*
* Try uspace handlers first.
*/
spinlock_lock(&irq_uspace_hash_table_lock);
lnk = hash_table_find(&irq_uspace_hash_table, key);
if (lnk) {
irq_t *irq;
irq = hash_table_get_instance(lnk, irq_t, link);
spinlock_unlock(&irq_uspace_hash_table_lock);
return irq;
}
spinlock_unlock(&irq_uspace_hash_table_lock);
/*
* Fallback to kernel handlers.
*/
spinlock_lock(&irq_kernel_hash_table_lock);
lnk = hash_table_find(&irq_kernel_hash_table, key);
if (lnk) {
irq_t *irq;
irq = hash_table_get_instance(lnk, irq_t, link);
spinlock_unlock(&irq_kernel_hash_table_lock);
return irq;
}
spinlock_unlock(&irq_kernel_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 % buckets;
}
/** 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_and_lock(). */
rv = ((irq->inr == inr) &&
(irq->claim(irq) == IRQ_ACCEPT));
} else {
/* Invoked by irq_find_and_lock(). */
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_and_lock() */
rv = (irq->claim(irq) == IRQ_ACCEPT);
} else {
/* Invoked by irq_find_and_lock() */
rv = (irq->devno == devno);
}
/* unlock only on non-match */
if (!rv)
spinlock_unlock(&irq->lock);
return rv;
}
/** @}
*/