// SPDX-License-Identifier: GPL-2.0
/*
 *      Copyright (C) 2000 YAEGASHI Takeshi
 *      Hitachi HD64461 companion chip support
 */

#include <linux/sched.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <asm/irq.h>
#include <asm/hd64461.h>

/* This belongs in cpu specific */
#define INTC_ICR1 0xA4140010UL

static void hd64461_mask_irq(struct irq_data *data)
{
        unsigned int irq = data->irq;
        unsigned short nimr;
        unsigned short mask = 1 << (irq - HD64461_IRQBASE);

        nimr = __raw_readw(HD64461_NIMR);
        nimr |= mask;
        __raw_writew(nimr, HD64461_NIMR);
}

static void hd64461_unmask_irq(struct irq_data *data)
{
        unsigned int irq = data->irq;
        unsigned short nimr;
        unsigned short mask = 1 << (irq - HD64461_IRQBASE);

        nimr = __raw_readw(HD64461_NIMR);
        nimr &= ~mask;
        __raw_writew(nimr, HD64461_NIMR);
}

static void hd64461_mask_and_ack_irq(struct irq_data *data)
{
        hd64461_mask_irq(data);

#ifdef CONFIG_HD64461_ENABLER
        if (data->irq == HD64461_IRQBASE + 13)
                __raw_writeb(0x00, HD64461_PCC1CSCR);
#endif
}

static struct irq_chip hd64461_irq_chip = {
        .name           = "HD64461-IRQ",
        .irq_mask       = hd64461_mask_irq,
        .irq_mask_ack   = hd64461_mask_and_ack_irq,
        .irq_unmask     = hd64461_unmask_irq,
};

static void hd64461_irq_demux(struct irq_desc *desc)
{
        unsigned short intv = __raw_readw(HD64461_NIRR);
        unsigned int ext_irq = HD64461_IRQBASE;

        intv &= (1 << HD64461_IRQ_NUM) - 1;

        for (; intv; intv >>= 1, ext_irq++) {
                if (!(intv & 1))
                        continue;

                generic_handle_irq(ext_irq);
        }
}

static int __init setup_hd64461(void)
{
        int irq_base, i;

        printk(KERN_INFO
               "HD64461 configured at 0x%x on irq %d(mapped into %d to %d)\n",
               HD64461_IOBASE, CONFIG_HD64461_IRQ, HD64461_IRQBASE,
               HD64461_IRQBASE + 15);

/* Should be at processor specific part.. */
#if defined(CONFIG_CPU_SUBTYPE_SH7709)
        __raw_writew(0x2240, INTC_ICR1);
#endif
        __raw_writew(0xffff, HD64461_NIMR);

        irq_base = irq_alloc_descs(HD64461_IRQBASE, HD64461_IRQBASE, 16, -1);
        if (IS_ERR_VALUE(irq_base)) {
                pr_err("%s: failed hooking irqs for HD64461\n", __func__);
                return irq_base;
        }

        for (i = 0; i < 16; i++)
                irq_set_chip_and_handler(irq_base + i, &hd64461_irq_chip,
                                         handle_level_irq);

        irq_set_chained_handler(CONFIG_HD64461_IRQ, hd64461_irq_demux);
        irq_set_irq_type(CONFIG_HD64461_IRQ, IRQ_TYPE_LEVEL_LOW);

#ifdef CONFIG_HD64461_ENABLER
        printk(KERN_INFO "HD64461: enabling PCMCIA devices\n");
        __raw_writeb(0x4c, HD64461_PCC1CSCIER);
        __raw_writeb(0x00, HD64461_PCC1CSCR);
#endif

        return 0;
}

module_init(setup_hd64461);