OpenWrt – Rev 1

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/*
 * Copyright (C) 2010 Scott Nicholas <neutronscott@scottn.us>
 * Copyright (C) 2012 Florian Fainelli <florian@openwrt.org>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/pm.h>
#include <linux/irq.h>
#include <asm/mipsregs.h>
#include <asm/irq_cpu.h>
#include <asm/irq.h>
#include <adm8668.h>

/* interrupt controller */
#define IRQ_STATUS_REG          0x00    /* Read */
#define IRQ_ENABLE_REG          0x08    /* Read/Write */
#define IRQ_DISABLE_REG         0x0C    /* Write */

#define IRQ_MASK                0xffff

static inline void intc_write_reg(u32 val, unsigned int reg)
{
        void __iomem *base = (void __iomem *)KSEG1ADDR(ADM8668_INTC_BASE);

        __raw_writel(val, base + reg);
}

static inline u32 intc_read_reg(unsigned int reg)
{
        void __iomem *base = (void __iomem *)KSEG1ADDR(ADM8668_INTC_BASE);

        return __raw_readl(base + reg);
}

static void adm8668_irq_cascade(void)
{
        int irq;
        u32 intsrc;

        intsrc = intc_read_reg(IRQ_STATUS_REG) & IRQ_MASK;
        if (intsrc) {
                irq = fls(intsrc) - 1;
                do_IRQ(irq);
        } else
                spurious_interrupt();
}

/*
 * System irq dispatch
 */
void plat_irq_dispatch(void)
{
        unsigned int pending;

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

        /* timer interrupt, that we renumbered */
        if (pending & STATUSF_IP7)
                do_IRQ(MIPS_CPU_IRQ_BASE + 7);
        else if (pending & STATUSF_IP2)
                adm8668_irq_cascade();
        else
                spurious_interrupt();
}

/*
 * enable 8668 irq
 */
static void enable_adm8668_irq(struct irq_data *d)
{
        intc_write_reg((1 << d->irq), IRQ_ENABLE_REG);
}


static void ack_adm8668_irq(struct irq_data *d)
{
        intc_write_reg((1 << d->irq), IRQ_DISABLE_REG);
}

/*
 * system irq type
 */

static struct irq_chip adm8668_irq_type = {
        .name = "adm8668",
        .irq_ack = ack_adm8668_irq,
        .irq_mask = ack_adm8668_irq,
        .irq_unmask = enable_adm8668_irq
};

/*
 * irq init
 */
static void __init init_adm8668_irqs(void)
{
        int i;

        /* disable all interrupts for the moment */
        intc_write_reg(IRQ_MASK, IRQ_DISABLE_REG);

        for (i = 0; i <= ADM8668_IRQ_MAX; i++)
                irq_set_chip_and_handler(i, &adm8668_irq_type,
                        handle_level_irq);

        /* hw0 is where our interrupts are uh.. interrupted at. */
        set_c0_status(IE_IRQ0);
}

/*
 * system init
 */
void __init arch_init_irq(void)
{
        mips_cpu_irq_init();
        init_adm8668_irqs();
}