// SPDX-License-Identifier: GPL-2.0

#define pr_fmt(fmt) "irq-ls-extirq: " fmt

#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/slab.h>

#include <dt-bindings/interrupt-controller/arm-gic.h>

#define MAXIRQ 12
#define LS1021A_SCFGREVCR 0x200

struct ls_extirq_data {
	void __iomem		*intpcr;
	raw_spinlock_t		lock;
	bool			big_endian;
	bool			is_ls1021a_or_ls1043a;
	u32			nirq;
	struct irq_fwspec	map[MAXIRQ];
};

static void ls_extirq_intpcr_rmw(struct ls_extirq_data *priv, u32 mask,
				 u32 value)
{
	u32 intpcr;

	/*
	 * Serialize concurrent calls to ls_extirq_set_type() from multiple
	 * IRQ descriptors, making sure the read-modify-write is atomic.
	 */
	raw_spin_lock(&priv->lock);

	if (priv->big_endian)
		intpcr = ioread32be(priv->intpcr);
	else
		intpcr = ioread32(priv->intpcr);

	intpcr &= ~mask;
	intpcr |= value;

	if (priv->big_endian)
		iowrite32be(intpcr, priv->intpcr);
	else
		iowrite32(intpcr, priv->intpcr);

	raw_spin_unlock(&priv->lock);
}

static int
ls_extirq_set_type(struct irq_data *data, unsigned int type)
{
	struct ls_extirq_data *priv = data->chip_data;
	irq_hw_number_t hwirq = data->hwirq;
	u32 value, mask;

	if (priv->is_ls1021a_or_ls1043a)
		mask = 1U << (31 - hwirq);
	else
		mask = 1U << hwirq;

	switch (type) {
	case IRQ_TYPE_LEVEL_LOW:
		type = IRQ_TYPE_LEVEL_HIGH;
		value = mask;
		break;
	case IRQ_TYPE_EDGE_FALLING:
		type = IRQ_TYPE_EDGE_RISING;
		value = mask;
		break;
	case IRQ_TYPE_LEVEL_HIGH:
	case IRQ_TYPE_EDGE_RISING:
		value = 0;
		break;
	default:
		return -EINVAL;
	}

	ls_extirq_intpcr_rmw(priv, mask, value);

	return irq_chip_set_type_parent(data, type);
}

static struct irq_chip ls_extirq_chip = {
	.name			= "ls-extirq",
	.irq_mask		= irq_chip_mask_parent,
	.irq_unmask		= irq_chip_unmask_parent,
	.irq_eoi		= irq_chip_eoi_parent,
	.irq_set_type		= ls_extirq_set_type,
	.irq_retrigger		= irq_chip_retrigger_hierarchy,
	.irq_set_affinity	= irq_chip_set_affinity_parent,
	.flags                  = IRQCHIP_SET_TYPE_MASKED | IRQCHIP_SKIP_SET_WAKE,
};

static int
ls_extirq_domain_alloc(struct irq_domain *domain, unsigned int virq,
		       unsigned int nr_irqs, void *arg)
{
	struct ls_extirq_data *priv = domain->host_data;
	struct irq_fwspec *fwspec = arg;
	irq_hw_number_t hwirq;

	if (fwspec->param_count != 2)
		return -EINVAL;

	hwirq = fwspec->param[0];
	if (hwirq >= priv->nirq)
		return -EINVAL;

	irq_domain_set_hwirq_and_chip(domain, virq, hwirq, &ls_extirq_chip,
				      priv);

	return irq_domain_alloc_irqs_parent(domain, virq, 1, &priv->map[hwirq]);
}

static const struct irq_domain_ops extirq_domain_ops = {
	.xlate		= irq_domain_xlate_twocell,
	.alloc		= ls_extirq_domain_alloc,
	.free		= irq_domain_free_irqs_common,
};

static int
ls_extirq_parse_map(struct ls_extirq_data *priv, struct device_node *node)
{
	const __be32 *map;
	u32 mapsize;
	int ret;

	map = of_get_property(node, "interrupt-map", &mapsize);
	if (!map)
		return -ENOENT;
	if (mapsize % sizeof(*map))
		return -EINVAL;
	mapsize /= sizeof(*map);

	while (mapsize) {
		struct device_node *ipar;
		u32 hwirq, intsize, j;

		if (mapsize < 3)
			return -EINVAL;
		hwirq = be32_to_cpup(map);
		if (hwirq >= MAXIRQ)
			return -EINVAL;
		priv->nirq = max(priv->nirq, hwirq + 1);

		ipar = of_find_node_by_phandle(be32_to_cpup(map + 2));
		map += 3;
		mapsize -= 3;
		if (!ipar)
			return -EINVAL;
		priv->map[hwirq].fwnode = &ipar->fwnode;
		ret = of_property_read_u32(ipar, "#interrupt-cells", &intsize);
		if (ret)
			return ret;

		if (intsize > mapsize)
			return -EINVAL;

		priv->map[hwirq].param_count = intsize;
		for (j = 0; j < intsize; ++j)
			priv->map[hwirq].param[j] = be32_to_cpup(map++);
		mapsize -= intsize;
	}
	return 0;
}

static int __init
ls_extirq_of_init(struct device_node *node, struct device_node *parent)
{
	struct irq_domain *domain, *parent_domain;
	struct ls_extirq_data *priv;
	int ret;

	parent_domain = irq_find_host(parent);
	if (!parent_domain) {
		pr_err("Cannot find parent domain\n");
		ret = -ENODEV;
		goto err_irq_find_host;
	}

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv) {
		ret = -ENOMEM;
		goto err_alloc_priv;
	}

	/*
	 * All extirq OF nodes are under a scfg/syscon node with
	 * the 'ranges' property
	 */
	priv->intpcr = of_iomap(node, 0);
	if (!priv->intpcr) {
		pr_err("Cannot ioremap OF node %pOF\n", node);
		ret = -ENOMEM;
		goto err_iomap;
	}

	ret = ls_extirq_parse_map(priv, node);
	if (ret)
		goto err_parse_map;

	priv->big_endian = of_device_is_big_endian(node->parent);
	priv->is_ls1021a_or_ls1043a = of_device_is_compatible(node, "fsl,ls1021a-extirq") ||
				      of_device_is_compatible(node, "fsl,ls1043a-extirq");
	raw_spin_lock_init(&priv->lock);

	domain = irq_domain_add_hierarchy(parent_domain, 0, priv->nirq, node,
					  &extirq_domain_ops, priv);
	if (!domain) {
		ret = -ENOMEM;
		goto err_add_hierarchy;
	}

	return 0;

err_add_hierarchy:
err_parse_map:
	iounmap(priv->intpcr);
err_iomap:
	kfree(priv);
err_alloc_priv:
err_irq_find_host:
	return ret;
}

IRQCHIP_DECLARE(ls1021a_extirq, "fsl,ls1021a-extirq", ls_extirq_of_init);
IRQCHIP_DECLARE(ls1043a_extirq, "fsl,ls1043a-extirq", ls_extirq_of_init);
IRQCHIP_DECLARE(ls1088a_extirq, "fsl,ls1088a-extirq", ls_extirq_of_init);