// SPDX-License-Identifier: GPL-2.0
/*
 * QUICC ENGINE I/O Ports Interrupt Controller
 *
 * Copyright (c) 2025 Christophe Leroy CS GROUP France (christophe.leroy@csgroup.eu)
 */

#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/platform_device.h>

/* QE IC registers offset */
#define CEPIER          0x0c
#define CEPIMR          0x10
#define CEPICR          0x14

struct qepic_data {
        void __iomem *reg;
        struct irq_domain *host;
};

static void qepic_mask(struct irq_data *d)
{
        struct qepic_data *data = irq_data_get_irq_chip_data(d);

        clrbits32(data->reg + CEPIMR, 1 << (31 - irqd_to_hwirq(d)));
}

static void qepic_unmask(struct irq_data *d)
{
        struct qepic_data *data = irq_data_get_irq_chip_data(d);

        setbits32(data->reg + CEPIMR, 1 << (31 - irqd_to_hwirq(d)));
}

static void qepic_end(struct irq_data *d)
{
        struct qepic_data *data = irq_data_get_irq_chip_data(d);

        out_be32(data->reg + CEPIER, 1 << (31 - irqd_to_hwirq(d)));
}

static int qepic_set_type(struct irq_data *d, unsigned int flow_type)
{
        struct qepic_data *data = irq_data_get_irq_chip_data(d);
        unsigned int vec = (unsigned int)irqd_to_hwirq(d);

        switch (flow_type & IRQ_TYPE_SENSE_MASK) {
        case IRQ_TYPE_EDGE_FALLING:
                setbits32(data->reg + CEPICR, 1 << (31 - vec));
                return 0;
        case IRQ_TYPE_EDGE_BOTH:
        case IRQ_TYPE_NONE:
                clrbits32(data->reg + CEPICR, 1 << (31 - vec));
                return 0;
        }
        return -EINVAL;
}

static struct irq_chip qepic = {
        .name = "QEPIC",
        .irq_mask = qepic_mask,
        .irq_unmask = qepic_unmask,
        .irq_eoi = qepic_end,
        .irq_set_type = qepic_set_type,
};

static int qepic_get_irq(struct irq_desc *desc)
{
        struct qepic_data *data = irq_desc_get_handler_data(desc);
        u32 event = in_be32(data->reg + CEPIER);

        if (!event)
                return -1;

        return irq_find_mapping(data->host, 32 - ffs(event));
}

static void qepic_cascade(struct irq_desc *desc)
{
        generic_handle_irq(qepic_get_irq(desc));
}

static int qepic_host_map(struct irq_domain *h, unsigned int virq, irq_hw_number_t hw)
{
        irq_set_chip_data(virq, h->host_data);
        irq_set_chip_and_handler(virq, &qepic, handle_fasteoi_irq);
        return 0;
}

static const struct irq_domain_ops qepic_host_ops = {
        .map = qepic_host_map,
};

static int qepic_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct qepic_data *data;
        int irq;

        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->reg = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(data->reg))
                return PTR_ERR(data->reg);

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        data->host = irq_domain_add_linear(dev->of_node, 32, &qepic_host_ops, data);
        if (!data->host)
                return -ENODEV;

        irq_set_chained_handler_and_data(irq, qepic_cascade, data);

        return 0;
}

static const struct of_device_id qepic_match[] = {
        {
                .compatible = "fsl,mpc8323-qe-ports-ic",
        },
        {},
};

static struct platform_driver qepic_driver = {
        .driver = {
                .name           = "qe_ports_ic",
                .of_match_table = qepic_match,
        },
        .probe  = qepic_probe,
};

static int __init qepic_init(void)
{
        return platform_driver_register(&qepic_driver);
}
arch_initcall(qepic_init);