// 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);