OpenWrt – Rev 2

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/*
 * Moschip MCS814x generic interrupt controller routines
 *
 * Copyright (C) 2012, Florian Fainelli <florian@openwrt.org>
 *
 * Licensed under the GPLv2
 */
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/irqdomain.h>

#include <asm/exception.h>
#include <asm/mach/irq.h>
#include <mach/mcs814x.h>

static void __iomem *mcs814x_intc_base;
static struct irq_domain *domain;

static void __init mcs814x_alloc_gc(void __iomem *base, unsigned int irq_start,
                                        unsigned int num)
{
        struct irq_chip_generic *gc;
        struct irq_chip_type *ct;

        if (irq_alloc_domain_generic_chips(domain, num, 1, "mcs814x-intc", handle_level_irq,
                IRQ_GC_INIT_MASK_CACHE, IRQ_NOREQUEST, 0))
                panic("unable to allocate domain generic irq chip");

        gc = irq_get_domain_generic_chip(domain, irq_start);
        if (!gc)
                panic("unable to get generic irq chip");

        gc->reg_base = base;
        ct = gc->chip_types;
        ct->chip.irq_ack = irq_gc_unmask_enable_reg;
        ct->chip.irq_mask = irq_gc_mask_clr_bit;
        ct->chip.irq_unmask = irq_gc_mask_set_bit;
        ct->regs.mask = MCS814X_IRQ_MASK;
        ct->regs.enable = MCS814X_IRQ_ICR;

        /* Clear all interrupts */
        writel_relaxed(0xffffffff, base + MCS814X_IRQ_ICR);
}

asmlinkage void __exception_irq_entry mcs814x_handle_irq(struct pt_regs *regs)
{
        u32 status, irq;

        do {
                /* read the status register */
                status = __raw_readl(mcs814x_intc_base + MCS814X_IRQ_STS0);
                if (!status)
                        break;

                irq = ffs(status) - 1;
                status |= (1 << irq);
                /* clear the interrupt */
                __raw_writel(status, mcs814x_intc_base + MCS814X_IRQ_STS0);
                /* call the generic handler */
                handle_domain_irq(domain, irq, regs);

        } while (1);
}

static const struct of_device_id mcs814x_intc_ids[] = {
        { .compatible = "moschip,mcs814x-intc" },
        { /* sentinel */ },
};

void __init mcs814x_of_irq_init(void)
{
        struct device_node *np;

        np = of_find_matching_node(NULL, mcs814x_intc_ids);
        if (!np)
                panic("unable to find compatible intc node in dtb\n");

        mcs814x_intc_base = of_iomap(np, 0);
        if (!mcs814x_intc_base)
                panic("unable to map intc cpu registers\n");

        domain = irq_domain_add_linear(np, 32, &irq_generic_chip_ops, NULL);
        if (!domain)
                panic("unable to add irq domain\n");
        irq_set_default_host(domain);

        of_node_put(np);

        mcs814x_alloc_gc(mcs814x_intc_base, 0, 32);
}