root / prex-0.9.0 / sys / kern / irq.c @ master
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/*-
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* Copyright (c) 2005-2007, Kohsuke Ohtani
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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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* 1. 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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* 2. 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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* 3. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* irq.c - interrupt request management routines.
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*/
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/**
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* We define the following two different types of interrupt services
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* in order to improve real-time performance.
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*
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* - Interrupt Service Routine (ISR)
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*
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* ISR is started by an actual hardware interrupt. The associated
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* interrupt is disabled in Interrupt Control Unit (ICU), and CPU
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* interrupt is enabled while ISR runs.
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* If ISR determines that the corresponding device generated the
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* interrupt, ISR must program the device to stop that interrupt.
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* Then, ISR should do minimum I/O operation and return control as
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* quickly as possible. ISR will run within a context of the thread
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* running when interrupt occurs. So, only few kernel services are
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* available within ISR.
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*
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* - Interrupt Service Thread (IST)
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*
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* IST is automatically activated if ISR returns INT_CONTINUE. It
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* will be called when the system enters safer condition than ISR.
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* A device driver should use IST to do heavy I/O operation as much
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* as possible. Since ISR for the same IRQ line may be invoked during
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* IST, the shared data, resources, and device registers must be
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* synchronized by disabling interrupts. IST does not have to be
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* reentrant because it is not interrupted by same IST itself.
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*/
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#include <kernel.h> |
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#include <event.h> |
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#include <kmem.h> |
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#include <sched.h> |
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#include <thread.h> |
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#include <irq.h> |
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#include <hal.h> |
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/* forward declarations */
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static void irq_thread(void *); |
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static struct irq *irq_table[MAXIRQS]; /* IRQ descriptor table */ |
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/*
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* irq_attach - attach ISR and IST to the specified interrupt.
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*
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* Returns irq handle, or panic on failure. The interrupt of
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* attached irq will be unmasked (enabled) in this routine.
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* TODO: Interrupt sharing is not supported, for now.
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*/
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irq_t |
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irq_attach(int vector, int pri, int shared, |
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int (*isr)(void *), void (*ist)(void *), void *data) |
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{ |
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struct irq *irq;
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int mode;
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ASSERT(isr != NULL);
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sched_lock(); |
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if ((irq = kmem_alloc(sizeof(*irq))) == NULL) |
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panic("irq_attach");
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memset(irq, 0, sizeof(*irq)); |
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irq->vector = vector; |
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irq->priority = pri; |
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irq->isr = isr; |
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irq->ist = ist; |
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irq->data = data; |
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if (ist != IST_NONE) {
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/*
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* Create a new thread for IST.
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*/
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irq->thread = kthread_create(&irq_thread, irq, ISTPRI(pri)); |
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if (irq->thread == NULL) |
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panic("irq_attach");
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event_init(&irq->istevt, "interrupt");
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} |
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irq_table[vector] = irq; |
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mode = shared ? IMODE_LEVEL : IMODE_EDGE; |
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interrupt_setup(vector, mode); |
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interrupt_unmask(vector, pri); |
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sched_unlock(); |
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DPRINTF(("IRQ%d attached priority=%d\n", vector, pri));
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return irq;
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} |
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/*
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* Detach an interrupt handler from the interrupt chain.
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* The detached interrupt will be masked off if nobody
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* attaches to it, anymore.
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*/
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void
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irq_detach(irq_t irq) |
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{ |
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ASSERT(irq != NULL);
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ASSERT(irq->vector < MAXIRQS); |
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interrupt_mask(irq->vector); |
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irq_table[irq->vector] = NULL;
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if (irq->thread != NULL) |
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kthread_terminate(irq->thread); |
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kmem_free(irq); |
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} |
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/*
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* Interrupt service thread.
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* This is a common dispatcher to all interrupt threads.
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*/
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static void |
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irq_thread(void *arg)
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{ |
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void (*fn)(void *); |
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void *data;
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struct irq *irq;
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splhigh(); |
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irq = (struct irq *)arg;
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fn = irq->ist; |
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data = irq->data; |
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for (;;) {
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if (irq->istreq <= 0) { |
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/*
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* Since the interrupt is disabled above,
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* an interrupt for this vector keeps
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* pending until this thread enters sleep
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* state. Thus, we don't lose any IST
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* requests even if the interrupt is fired
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* here.
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*/
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sched_sleep(&irq->istevt); |
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} |
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irq->istreq--; |
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ASSERT(irq->istreq >= 0);
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/*
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* Call IST
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*/
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spl0(); |
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(*fn)(data); |
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splhigh(); |
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} |
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/* NOTREACHED */
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} |
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/*
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* Interrupt handler.
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*
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* This routine will call the corresponding ISR for the
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* requested interrupt vector. HAL code must call this
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* routine with scheduler locked.
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*/
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void
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irq_handler(int vector)
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{ |
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struct irq *irq;
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int rc;
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irq = irq_table[vector]; |
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if (irq == NULL) { |
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DPRINTF(("Random interrupt ignored\n"));
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return;
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} |
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ASSERT(irq->isr != NULL);
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/* Profile */
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irq->count++; |
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/*
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* Call ISR
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*/
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rc = (*irq->isr)(irq->data); |
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if (rc == INT_CONTINUE) {
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/*
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* Kick IST
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*/
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ASSERT(irq->ist != IST_NONE); |
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irq->istreq++; |
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sched_wakeup(&irq->istevt); |
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ASSERT(irq->istreq != 0);
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} |
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} |
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/*
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* Return irq information.
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*/
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int
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irq_info(struct irqinfo *info)
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{ |
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int vec = info->cookie;
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int found = 0; |
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struct irq *irq;
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while (vec < MAXIRQS) {
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if (irq_table[vec]) {
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found = 1;
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break;
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} |
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vec++; |
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} |
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if (!found)
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return ESRCH;
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irq = irq_table[vec]; |
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info->vector = irq->vector; |
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info->count = irq->count; |
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info->priority = irq->priority; |
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info->istreq = irq->istreq; |
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info->thread = irq->thread; |
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info->cookie = vec + 1;
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return 0; |
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} |
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/*
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* Start interrupt processing.
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*/
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void
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irq_init(void)
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{ |
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interrupt_init(); |
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/* Enable interrupts */
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spl0(); |
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} |