// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2013 Altera Corporation
 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
 * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
 *
 * based on irq.c from m68k which is:
 *
 * Copyright (C) 2007 Greg Ungerer <gerg@snapgear.com>
 */

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/of.h>

static u32 ienable;

asmlinkage void do_IRQ(int hwirq, struct pt_regs *regs)
{
        struct pt_regs *oldregs = set_irq_regs(regs);

        irq_enter();
        generic_handle_domain_irq(NULL, hwirq);
        irq_exit();

        set_irq_regs(oldregs);
}

static void chip_unmask(struct irq_data *d)
{
        ienable |= (1 << d->hwirq);
        WRCTL(CTL_IENABLE, ienable);
}

static void chip_mask(struct irq_data *d)
{
        ienable &= ~(1 << d->hwirq);
        WRCTL(CTL_IENABLE, ienable);
}

static struct irq_chip m_irq_chip = {
        .name           = "NIOS2-INTC",
        .irq_unmask     = chip_unmask,
        .irq_mask       = chip_mask,
};

static int irq_map(struct irq_domain *h, unsigned int virq,
                                irq_hw_number_t hw_irq_num)
{
        irq_set_chip_and_handler(virq, &m_irq_chip, handle_level_irq);

        return 0;
}

static const struct irq_domain_ops irq_ops = {
        .map    = irq_map,
        .xlate  = irq_domain_xlate_onecell,
};

void __init init_IRQ(void)
{
        struct irq_domain *domain;
        struct device_node *node;

        node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.0");
        if (!node)
                node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.1");

        BUG_ON(!node);

        domain = irq_domain_create_linear(of_fwnode_handle(node),
                                          NIOS2_CPU_NR_IRQS, &irq_ops, NULL);
        BUG_ON(!domain);

        irq_set_default_domain(domain);
        of_node_put(node);
        /* Load the initial ienable value */
        ienable = RDCTL(CTL_IENABLE);
}