irq.c

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/*
 *  Interrupt handing routines for NEC VR4100 series.
 *
 *  Copyright (C) 2005-2007  Yoichi Yuasa <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/irq.h>

#include <asm/irq_cpu.h>
#include <asm/vr41xx/irq.h>

typedef struct irq_cascade {
    int (*get_irq)(unsigned int);
} irq_cascade_t;

static irq_cascade_t irq_cascade[NR_IRQS] __cacheline_aligned;

static struct irqaction cascade_irqaction = {
    .handler    = no_action,
    .name       = "cascade",
    .flags      = IRQF_NO_THREAD,
};

int cascade_irq(unsigned int irq, int (*get_irq)(unsigned int))
{
    int retval = 0;

    if (irq >= NR_IRQS)
        return -EINVAL;

    if (irq_cascade[irq].get_irq != NULL)
        free_irq(irq, NULL);

    irq_cascade[irq].get_irq = get_irq;

    if (get_irq != NULL) {
        retval = setup_irq(irq, &cascade_irqaction);
        if (retval < 0)
            irq_cascade[irq].get_irq = NULL;
    }

    return retval;
}

EXPORT_SYMBOL_GPL(cascade_irq);

static void irq_dispatch(unsigned int irq)
{
    irq_cascade_t *cascade;

    if (irq >= NR_IRQS) {
        atomic_inc(&irq_err_count);
        return;
    }

    cascade = irq_cascade + irq;
    if (cascade->get_irq != NULL) {
        struct irq_desc *desc = irq_to_desc(irq);
        struct irq_data *idata = irq_desc_get_irq_data(desc);
        struct irq_chip *chip = irq_desc_get_chip(desc);
        int ret;

        if (chip->irq_mask_ack)
            chip->irq_mask_ack(idata);
        else {
            chip->irq_mask(idata);
            chip->irq_ack(idata);
        }
        ret = cascade->get_irq(irq);
        irq = ret;
        if (ret < 0)
            atomic_inc(&irq_err_count);
        else
            irq_dispatch(irq);
        if (!irqd_irq_disabled(idata) && chip->irq_unmask)
            chip->irq_unmask(idata);
    } else
        do_IRQ(irq);
}

asmlinkage void plat_irq_dispatch(void)
{
    unsigned int pending = read_c0_cause() & read_c0_status() & ST0_IM;

    if (pending & CAUSEF_IP7)
        do_IRQ(TIMER_IRQ);
    else if (pending & 0x7800) {
        if (pending & CAUSEF_IP3)
            irq_dispatch(INT1_IRQ);
        else if (pending & CAUSEF_IP4)
            irq_dispatch(INT2_IRQ);
        else if (pending & CAUSEF_IP5)
            irq_dispatch(INT3_IRQ);
        else if (pending & CAUSEF_IP6)
            irq_dispatch(INT4_IRQ);
    } else if (pending & CAUSEF_IP2)
        irq_dispatch(INT0_IRQ);
    else if (pending & CAUSEF_IP0)
        do_IRQ(MIPS_SOFTINT0_IRQ);
    else if (pending & CAUSEF_IP1)
        do_IRQ(MIPS_SOFTINT1_IRQ);
    else
        spurious_interrupt();
}

void __init arch_init_irq(void)
{
    mips_cpu_irq_init();
}