irq.c

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/*
 * Toshiba RBTX4939 interrupt routines
 * Based on linux/arch/mips/txx9/rbtx4938/irq.c,
 *      and RBTX49xx patch from CELF patch archive.
 *
 * Copyright (C) 2000-2001,2005-2006 Toshiba Corporation
 * 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
 * terms of the GNU General Public License version 2. This program is
 * licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <asm/mipsregs.h>
#include <asm/txx9/rbtx4939.h>

/*
 * RBTX4939 IOC controller definition
 */

static void rbtx4939_ioc_irq_unmask(struct irq_data *d)
{
    int ioc_nr = d->irq - RBTX4939_IRQ_IOC;

    writeb(readb(rbtx4939_ien_addr) | (1 << ioc_nr), rbtx4939_ien_addr);
}

static void rbtx4939_ioc_irq_mask(struct irq_data *d)
{
    int ioc_nr = d->irq - RBTX4939_IRQ_IOC;

    writeb(readb(rbtx4939_ien_addr) & ~(1 << ioc_nr), rbtx4939_ien_addr);
    mmiowb();
}

static struct irq_chip rbtx4939_ioc_irq_chip = {
    .name       = "IOC",
    .irq_mask   = rbtx4939_ioc_irq_mask,
    .irq_unmask = rbtx4939_ioc_irq_unmask,
};


static inline int rbtx4939_ioc_irqroute(void)
{
    unsigned char istat = readb(rbtx4939_ifac2_addr);

    if (unlikely(istat == 0))
        return -1;
    return RBTX4939_IRQ_IOC + __fls8(istat);
}

static int rbtx4939_irq_dispatch(int pending)
{
    int irq;

    if (pending & CAUSEF_IP7)
        return MIPS_CPU_IRQ_BASE + 7;
    irq = tx4939_irq();
    if (likely(irq >= 0)) {
        /* redirect IOC interrupts */
        switch (irq) {
        case RBTX4939_IRQ_IOCINT:
            irq = rbtx4939_ioc_irqroute();
            break;
        }
    } else if (pending & CAUSEF_IP0)
        irq = MIPS_CPU_IRQ_BASE + 0;
    else if (pending & CAUSEF_IP1)
        irq = MIPS_CPU_IRQ_BASE + 1;
    else
        irq = -1;
    return irq;
}

void __init rbtx4939_irq_setup(void)
{
    int i;

    /* mask all IOC interrupts */
    writeb(0, rbtx4939_ien_addr);

    /* clear SoftInt interrupts */
    writeb(0, rbtx4939_softint_addr);

    txx9_irq_dispatch = rbtx4939_irq_dispatch;

    tx4939_irq_init();
    for (i = RBTX4939_IRQ_IOC;
         i < RBTX4939_IRQ_IOC + RBTX4939_NR_IRQ_IOC; i++)
        irq_set_chip_and_handler(i, &rbtx4939_ioc_irq_chip,
                     handle_level_irq);

    irq_set_chained_handler(RBTX4939_IRQ_IOCINT, handle_simple_irq);
}