/*
 *  Atheros AR71xx/AR724x/AR913x MISC interrupt controller
 *
 *  Copyright (C) 2015 Alban Bedel <albeu@free.fr>
 *  Copyright (C) 2010-2011 Jaiganesh Narayanan <jnarayanan@atheros.com>
 *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
 *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
 *
 *  Parts of this file are based on Atheros' 2.6.15/2.6.31 BSP
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License version 2 as published
 *  by the Free Software Foundation.
 */

#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>

#define AR71XX_RESET_REG_MISC_INT_STATUS	0
#define AR71XX_RESET_REG_MISC_INT_ENABLE	4

#define ATH79_MISC_IRQ_COUNT			32

static void ath79_misc_irq_handler(struct irq_desc *desc)
{
	struct irq_domain *domain = irq_desc_get_handler_data(desc);
	struct irq_chip *chip = irq_desc_get_chip(desc);
	void __iomem *base = domain->host_data;
	u32 pending;

	chained_irq_enter(chip, desc);

	pending = __raw_readl(base + AR71XX_RESET_REG_MISC_INT_STATUS) &
		  __raw_readl(base + AR71XX_RESET_REG_MISC_INT_ENABLE);

	if (!pending) {
		spurious_interrupt();
		chained_irq_exit(chip, desc);
		return;
	}

	while (pending) {
		int bit = __ffs(pending);

		generic_handle_irq(irq_linear_revmap(domain, bit));
		pending &= ~BIT(bit);
	}

	chained_irq_exit(chip, desc);
}

static void ar71xx_misc_irq_unmask(struct irq_data *d)
{
	void __iomem *base = irq_data_get_irq_chip_data(d);
	unsigned int irq = d->hwirq;
	u32 t;

	t = __raw_readl(base + AR71XX_RESET_REG_MISC_INT_ENABLE);
	__raw_writel(t | BIT(irq), base + AR71XX_RESET_REG_MISC_INT_ENABLE);

	/* flush write */
	__raw_readl(base + AR71XX_RESET_REG_MISC_INT_ENABLE);
}

static void ar71xx_misc_irq_mask(struct irq_data *d)
{
	void __iomem *base = irq_data_get_irq_chip_data(d);
	unsigned int irq = d->hwirq;
	u32 t;

	t = __raw_readl(base + AR71XX_RESET_REG_MISC_INT_ENABLE);
	__raw_writel(t & ~BIT(irq), base + AR71XX_RESET_REG_MISC_INT_ENABLE);

	/* flush write */
	__raw_readl(base + AR71XX_RESET_REG_MISC_INT_ENABLE);
}

static void ar724x_misc_irq_ack(struct irq_data *d)
{
	void __iomem *base = irq_data_get_irq_chip_data(d);
	unsigned int irq = d->hwirq;
	u32 t;

	t = __raw_readl(base + AR71XX_RESET_REG_MISC_INT_STATUS);
	__raw_writel(t & ~BIT(irq), base + AR71XX_RESET_REG_MISC_INT_STATUS);

	/* flush write */
	__raw_readl(base + AR71XX_RESET_REG_MISC_INT_STATUS);
}

static struct irq_chip ath79_misc_irq_chip = {
	.name		= "MISC",
	.irq_unmask	= ar71xx_misc_irq_unmask,
	.irq_mask	= ar71xx_misc_irq_mask,
};

static int misc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
{
	irq_set_chip_and_handler(irq, &ath79_misc_irq_chip, handle_level_irq);
	irq_set_chip_data(irq, d->host_data);
	return 0;
}

static const struct irq_domain_ops misc_irq_domain_ops = {
	.xlate = irq_domain_xlate_onecell,
	.map = misc_map,
};

static void __init ath79_misc_intc_domain_init(
	struct irq_domain *domain, int irq)
{
	void __iomem *base = domain->host_data;

	/* Disable and clear all interrupts */
	__raw_writel(0, base + AR71XX_RESET_REG_MISC_INT_ENABLE);
	__raw_writel(0, base + AR71XX_RESET_REG_MISC_INT_STATUS);

	irq_set_chained_handler_and_data(irq, ath79_misc_irq_handler, domain);
}

static int __init ath79_misc_intc_of_init(
	struct device_node *node, struct device_node *parent)
{
	struct irq_domain *domain;
	void __iomem *base;
	int irq;

	irq = irq_of_parse_and_map(node, 0);
	if (!irq) {
		pr_err("Failed to get MISC IRQ\n");
		return -EINVAL;
	}

	base = of_iomap(node, 0);
	if (!base) {
		pr_err("Failed to get MISC IRQ registers\n");
		return -ENOMEM;
	}

	domain = irq_domain_add_linear(node, ATH79_MISC_IRQ_COUNT,
				&misc_irq_domain_ops, base);
	if (!domain) {
		pr_err("Failed to add MISC irqdomain\n");
		return -EINVAL;
	}

	ath79_misc_intc_domain_init(domain, irq);
	return 0;
}

static int __init ar7100_misc_intc_of_init(
	struct device_node *node, struct device_node *parent)
{
	ath79_misc_irq_chip.irq_mask_ack = ar71xx_misc_irq_mask;
	return ath79_misc_intc_of_init(node, parent);
}

IRQCHIP_DECLARE(ar7100_misc_intc, "qca,ar7100-misc-intc",
		ar7100_misc_intc_of_init);

static int __init ar7240_misc_intc_of_init(
	struct device_node *node, struct device_node *parent)
{
	ath79_misc_irq_chip.irq_ack = ar724x_misc_irq_ack;
	return ath79_misc_intc_of_init(node, parent);
}

IRQCHIP_DECLARE(ar7240_misc_intc, "qca,ar7240-misc-intc",
		ar7240_misc_intc_of_init);

void __init ath79_misc_irq_init(void __iomem *regs, int irq,
				int irq_base, bool is_ar71xx)
{
	struct irq_domain *domain;

	if (is_ar71xx)
		ath79_misc_irq_chip.irq_mask_ack = ar71xx_misc_irq_mask;
	else
		ath79_misc_irq_chip.irq_ack = ar724x_misc_irq_ack;

	domain = irq_domain_add_legacy(NULL, ATH79_MISC_IRQ_COUNT,
			irq_base, 0, &misc_irq_domain_ops, regs);
	if (!domain)
		panic("Failed to create MISC irqdomain");

	ath79_misc_intc_domain_init(domain, irq);
}