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Viewing changes to kernel/arch/mips32/src/interrupt.c

  • Committer: Martin Decky
  • Date: 2009-08-04 11:19:19 UTC
  • Revision ID: martin@uranus.dsrg.hide.ms.mff.cuni.cz-20090804111919-evyclddlr3v5lhmp
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kernel/arch/mips32/src/interrupt.c
 
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/*
 
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 * Copyright (c) 2003-2004 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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/** @addtogroup mips32interrupt
 
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 * @{
 
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 */
 
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/** @file
 
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 */
 
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#include <interrupt.h>
 
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#include <arch/interrupt.h>
 
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#include <arch/types.h>
 
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#include <arch.h>
 
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#include <arch/cp0.h>
 
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#include <time/clock.h>
 
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#include <ipc/sysipc.h>
 
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#include <ddi/device.h>
 
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#define IRQ_COUNT   8
 
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#define TIMER_IRQ   7
 
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#define DORDER_IRQ  5
 
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function virtual_timer_fnc = NULL;
 
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static irq_t timer_irq;
 
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/** Disable interrupts.
 
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 *
 
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 * @return Old interrupt priority level.
 
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 */
 
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ipl_t interrupts_disable(void)
 
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{
 
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        ipl_t ipl = (ipl_t) cp0_status_read();
 
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        cp0_status_write(ipl & ~cp0_status_ie_enabled_bit);
 
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        return ipl;
 
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}
 
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/** Enable interrupts.
 
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 *
 
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 * @return Old interrupt priority level.
 
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 */
 
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ipl_t interrupts_enable(void)
 
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{
 
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        ipl_t ipl = (ipl_t) cp0_status_read();
 
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        cp0_status_write(ipl | cp0_status_ie_enabled_bit);
 
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        return ipl;
 
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}
 
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/** Restore interrupt priority level.
 
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 *
 
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 * @param ipl Saved interrupt priority level.
 
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 */
 
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void interrupts_restore(ipl_t ipl)
 
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{
 
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        cp0_status_write(cp0_status_read() | (ipl & cp0_status_ie_enabled_bit));
 
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}
 
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/** Read interrupt priority level.
 
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 *
 
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 * @return Current interrupt priority level.
 
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 */
 
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ipl_t interrupts_read(void)
 
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{
 
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        return cp0_status_read();
 
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}
 
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/* TODO: This is SMP unsafe!!! */
 
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uint32_t count_hi = 0;
 
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static unsigned long nextcount;
 
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static unsigned long lastcount;
 
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/** Start hardware clock */
 
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static void timer_start(void)
 
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{
 
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        lastcount = cp0_count_read();
 
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        nextcount = cp0_compare_value + cp0_count_read();
 
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        cp0_compare_write(nextcount);
 
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}
 
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static irq_ownership_t timer_claim(irq_t *irq)
 
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{
 
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        return IRQ_ACCEPT;
 
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}
 
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static void timer_irq_handler(irq_t *irq)
 
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{
 
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        unsigned long drift;
 
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        if (cp0_count_read() < lastcount)
 
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                /* Count overflow detected */
 
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                count_hi++;
 
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        lastcount = cp0_count_read();
 
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        drift = cp0_count_read() - nextcount;
 
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        while (drift > cp0_compare_value) {
 
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                drift -= cp0_compare_value;
 
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                CPU->missed_clock_ticks++;
 
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        }
 
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        nextcount = cp0_count_read() + cp0_compare_value - drift;
 
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        cp0_compare_write(nextcount);
 
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        /*
 
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         * We are holding a lock which prevents preemption.
 
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         * Release the lock, call clock() and reacquire the lock again.
 
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         */
 
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        spinlock_unlock(&irq->lock);
 
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        clock();
 
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        spinlock_lock(&irq->lock);
 
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        if (virtual_timer_fnc != NULL)
 
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                virtual_timer_fnc();
 
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}
 
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/* Initialize basic tables for exception dispatching */
 
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void interrupt_init(void)
 
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{
 
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        irq_init(IRQ_COUNT, IRQ_COUNT);
 
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        irq_initialize(&timer_irq);
 
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        timer_irq.devno = device_assign_devno();
 
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        timer_irq.inr = TIMER_IRQ;
 
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        timer_irq.claim = timer_claim;
 
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        timer_irq.handler = timer_irq_handler;
 
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        irq_register(&timer_irq);
 
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        timer_start();
 
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        cp0_unmask_int(TIMER_IRQ);
 
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}
 
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/** @}
 
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 */