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/*
 *  ADM5120 specific interrupt handlers
 *
 *  Copyright (C) 2007-2008 Gabor Juhos <juhosg@openwrt.org>
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License version 2 as published
 *  by the Free Software Foundation.
 *
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/version.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/bitops.h>

#include <asm/irq_cpu.h>
#include <asm/mipsregs.h>

#include <asm/mach-adm5120/adm5120_defs.h>

static void adm5120_intc_irq_unmask(struct irq_data *d);
static void adm5120_intc_irq_mask(struct irq_data *d);
static int  adm5120_intc_irq_set_type(struct irq_data *d, unsigned int flow_type);

static inline void intc_write_reg(unsigned int reg, u32 val)
{
        void __iomem *base = (void __iomem *)KSEG1ADDR(ADM5120_INTC_BASE);

        __raw_writel(val, base + reg);
}

static inline u32 intc_read_reg(unsigned int reg)
{
        void __iomem *base = (void __iomem *)KSEG1ADDR(ADM5120_INTC_BASE);

        return __raw_readl(base + reg);
}

static struct irq_chip adm5120_intc_irq_chip = {
        .name           = "INTC",
        .irq_unmask     = adm5120_intc_irq_unmask,
        .irq_mask       = adm5120_intc_irq_mask,
        .irq_mask_ack   = adm5120_intc_irq_mask,
        .irq_set_type   = adm5120_intc_irq_set_type
};

static struct irqaction adm5120_intc_irq_action = {
        .handler        = no_action,
        .name           = "cascade [INTC]"
};

static void adm5120_intc_irq_unmask(struct irq_data *d)
{
        intc_write_reg(INTC_REG_IRQ_ENABLE, 1 << (d->irq - ADM5120_INTC_IRQ_BASE));
}

static void adm5120_intc_irq_mask(struct irq_data *d)
{
        intc_write_reg(INTC_REG_IRQ_DISABLE, 1 << (d->irq - ADM5120_INTC_IRQ_BASE));
}

static int adm5120_intc_irq_set_type(struct irq_data *d, unsigned int flow_type)
{
        unsigned int irq = d->irq;
        unsigned int sense;
        unsigned long mode;
        int err = 0;

        sense = flow_type & (IRQ_TYPE_SENSE_MASK);
        switch (sense) {
        case IRQ_TYPE_NONE:
        case IRQ_TYPE_LEVEL_HIGH:
                break;
        case IRQ_TYPE_LEVEL_LOW:
                switch (irq) {
                case ADM5120_IRQ_GPIO2:
                case ADM5120_IRQ_GPIO4:
                        break;
                default:
                        err = -EINVAL;
                        break;
                }
                break;
        default:
                err = -EINVAL;
                break;
        }

        if (err)
                return err;

        switch (irq) {
        case ADM5120_IRQ_GPIO2:
        case ADM5120_IRQ_GPIO4:
                mode = intc_read_reg(INTC_REG_INT_MODE);
                if (sense == IRQ_TYPE_LEVEL_LOW)
                        mode |= (1 << (irq - ADM5120_INTC_IRQ_BASE));
                else
                        mode &= ~(1 << (irq - ADM5120_INTC_IRQ_BASE));

                intc_write_reg(INTC_REG_INT_MODE, mode);
                break;
        }

        return 0;
}

static void adm5120_intc_irq_dispatch(void)
{
        unsigned long status;
        int irq;

        status = intc_read_reg(INTC_REG_IRQ_STATUS) & INTC_INT_ALL;
        if (status) {
                irq = ADM5120_INTC_IRQ_BASE + fls(status) - 1;
                do_IRQ(irq);
        } else
                spurious_interrupt();
}

asmlinkage void plat_irq_dispatch(void)
{
        unsigned long pending;

        pending = read_c0_status() & read_c0_cause() & ST0_IM;

        if (pending & STATUSF_IP7)
                do_IRQ(ADM5120_IRQ_COUNTER);
        else if (pending & STATUSF_IP2)
                adm5120_intc_irq_dispatch();
        else
                spurious_interrupt();
}

#define INTC_IRQ_STATUS (IRQ_LEVEL | IRQ_TYPE_LEVEL_HIGH | IRQ_DISABLED)
static void __init adm5120_intc_irq_init(void)
{
        int i;

        /* disable all interrupts */
        intc_write_reg(INTC_REG_IRQ_DISABLE, INTC_INT_ALL);

        /* setup all interrupts to generate IRQ instead of FIQ */
        intc_write_reg(INTC_REG_INT_MODE, 0);

        /* set active level for all external interrupts to HIGH */
        intc_write_reg(INTC_REG_INT_LEVEL, 0);

        /* disable usage of the TEST_SOURCE register */
        intc_write_reg(INTC_REG_IRQ_SOURCE_SELECT, 0);

        for (i = ADM5120_INTC_IRQ_BASE;
                i <= ADM5120_INTC_IRQ_BASE + INTC_IRQ_LAST;
                i++) {
                irq_set_chip_and_handler(i, &adm5120_intc_irq_chip,
                        handle_level_irq);
        }

        setup_irq(ADM5120_IRQ_INTC, &adm5120_intc_irq_action);
}

void __init arch_init_irq(void)
{
        mips_cpu_irq_init();
        adm5120_intc_irq_init();
}