// 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 ls_extirq_probe(struct platform_device *pdev)
{
        struct irq_domain *domain, *parent_domain;
        struct device_node *node, *parent;
        struct device *dev = &pdev->dev;
        struct ls_extirq_data *priv;
        int ret;

        node = dev->of_node;
        parent = of_irq_find_parent(node);
        if (!parent)
                return dev_err_probe(dev, -ENODEV, "Failed to get IRQ parent node\n");

        parent_domain = irq_find_host(parent);
        if (!parent_domain)
                return dev_err_probe(dev, -EPROBE_DEFER, "Cannot find parent domain\n");

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return dev_err_probe(dev, -ENOMEM, "Failed to allocate memory\n");

        priv->intpcr = devm_of_iomap(dev, node, 0, NULL);
        if (IS_ERR(priv->intpcr)) {
                return dev_err_probe(dev, PTR_ERR(priv->intpcr),
                                     "Cannot ioremap OF node %pOF\n", node);
        }

        ret = ls_extirq_parse_map(priv, node);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to parse IRQ map\n");

        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_create_hierarchy(parent_domain, 0, priv->nirq, of_fwnode_handle(node),
                                             &extirq_domain_ops, priv);
        if (!domain)
                return dev_err_probe(dev, -ENOMEM, "Failed to add IRQ domain\n");

        return 0;
}

static const struct of_device_id ls_extirq_dt_ids[] = {
        { .compatible = "fsl,ls1021a-extirq" },
        { .compatible = "fsl,ls1043a-extirq" },
        { .compatible = "fsl,ls1088a-extirq" },
        {}
};
MODULE_DEVICE_TABLE(of, ls_extirq_dt_ids);

static struct platform_driver ls_extirq_driver = {
        .probe = ls_extirq_probe,
        .driver = {
                .name = "ls-extirq",
                .of_match_table = ls_extirq_dt_ids,
        }
};

builtin_platform_driver(ls_extirq_driver);