// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright 2017 NXP
 * Copyright (C) 2018 Pengutronix, Lucas Stach <kernel@pengutronix.de>
 */

#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/spinlock.h>

#define CTRL_STRIDE_OFF(_t, _r) (_t * 4 * _r)
#define CHANCTRL                0x0
#define CHANMASK(n, t)          (CTRL_STRIDE_OFF(t, 0) + 0x4 * (n) + 0x4)
#define CHANSET(n, t)           (CTRL_STRIDE_OFF(t, 1) + 0x4 * (n) + 0x4)
#define CHANSTATUS(n, t)        (CTRL_STRIDE_OFF(t, 2) + 0x4 * (n) + 0x4)
#define CHAN_MINTDIS(t)         (CTRL_STRIDE_OFF(t, 3) + 0x4)
#define CHAN_MASTRSTAT(t)       (CTRL_STRIDE_OFF(t, 3) + 0x8)

#define CHAN_MAX_OUTPUT_INT     0xF

struct irqsteer_data {
        void __iomem            *regs;
        struct clk              *ipg_clk;
        int                     irq[CHAN_MAX_OUTPUT_INT];
        int                     irq_count;
        raw_spinlock_t          lock;
        int                     reg_num;
        int                     channel;
        struct irq_domain       *domain;
        u32                     *saved_reg;
        struct device           *dev;
};

static int imx_irqsteer_get_reg_index(struct irqsteer_data *data,
                                      unsigned long irqnum)
{
        return (data->reg_num - irqnum / 32 - 1);
}

static void imx_irqsteer_irq_unmask(struct irq_data *d)
{
        struct irqsteer_data *data = d->chip_data;
        int idx = imx_irqsteer_get_reg_index(data, d->hwirq);
        unsigned long flags;
        u32 val;

        raw_spin_lock_irqsave(&data->lock, flags);
        val = readl_relaxed(data->regs + CHANMASK(idx, data->reg_num));
        val |= BIT(d->hwirq % 32);
        writel_relaxed(val, data->regs + CHANMASK(idx, data->reg_num));
        raw_spin_unlock_irqrestore(&data->lock, flags);
}

static void imx_irqsteer_irq_mask(struct irq_data *d)
{
        struct irqsteer_data *data = d->chip_data;
        int idx = imx_irqsteer_get_reg_index(data, d->hwirq);
        unsigned long flags;
        u32 val;

        raw_spin_lock_irqsave(&data->lock, flags);
        val = readl_relaxed(data->regs + CHANMASK(idx, data->reg_num));
        val &= ~BIT(d->hwirq % 32);
        writel_relaxed(val, data->regs + CHANMASK(idx, data->reg_num));
        raw_spin_unlock_irqrestore(&data->lock, flags);
}

static void imx_irqsteer_irq_bus_lock(struct irq_data *d)
{
        struct irqsteer_data *data = d->chip_data;

        pm_runtime_get_sync(data->dev);
}

static void imx_irqsteer_irq_bus_sync_unlock(struct irq_data *d)
{
        struct irqsteer_data *data = d->chip_data;

        pm_runtime_put_autosuspend(data->dev);
}

static const struct irq_chip imx_irqsteer_irq_chip = {
        .name                   = "irqsteer",
        .irq_mask               = imx_irqsteer_irq_mask,
        .irq_unmask             = imx_irqsteer_irq_unmask,
        .irq_bus_lock           = imx_irqsteer_irq_bus_lock,
        .irq_bus_sync_unlock    = imx_irqsteer_irq_bus_sync_unlock,
};

static int imx_irqsteer_irq_map(struct irq_domain *h, unsigned int irq,
                                irq_hw_number_t hwirq)
{
        irq_set_status_flags(irq, IRQ_LEVEL);
        irq_set_chip_data(irq, h->host_data);
        irq_set_chip_and_handler(irq, &imx_irqsteer_irq_chip, handle_level_irq);

        return 0;
}

static const struct irq_domain_ops imx_irqsteer_domain_ops = {
        .map            = imx_irqsteer_irq_map,
        .xlate          = irq_domain_xlate_onecell,
};

static int imx_irqsteer_get_hwirq_base(struct irqsteer_data *data, u32 irq)
{
        int i;

        for (i = 0; i < data->irq_count; i++) {
                if (data->irq[i] == irq)
                        return i * 64;
        }

        return -EINVAL;
}

static void imx_irqsteer_irq_handler(struct irq_desc *desc)
{
        struct irqsteer_data *data = irq_desc_get_handler_data(desc);
        int hwirq;
        int irq, i;

        chained_irq_enter(irq_desc_get_chip(desc), desc);

        irq = irq_desc_get_irq(desc);
        hwirq = imx_irqsteer_get_hwirq_base(data, irq);
        if (hwirq < 0) {
                pr_warn("%s: unable to get hwirq base for irq %d\n",
                        __func__, irq);
                return;
        }

        for (i = 0; i < 2; i++, hwirq += 32) {
                int idx = imx_irqsteer_get_reg_index(data, hwirq);
                unsigned long irqmap;
                int pos;

                if (hwirq >= data->reg_num * 32)
                        break;

                irqmap = readl_relaxed(data->regs +
                                       CHANSTATUS(idx, data->reg_num));

                for_each_set_bit(pos, &irqmap, 32)
                        generic_handle_domain_irq(data->domain, pos + hwirq);
        }

        chained_irq_exit(irq_desc_get_chip(desc), desc);
}

static int imx_irqsteer_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct irqsteer_data *data;
        u32 irqs_num;
        int i, ret;

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

        data->dev = &pdev->dev;
        data->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(data->regs)) {
                dev_err(&pdev->dev, "failed to initialize reg\n");
                return PTR_ERR(data->regs);
        }

        data->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
        if (IS_ERR(data->ipg_clk))
                return dev_err_probe(&pdev->dev, PTR_ERR(data->ipg_clk),
                                     "failed to get ipg clk\n");

        raw_spin_lock_init(&data->lock);

        ret = of_property_read_u32(np, "fsl,num-irqs", &irqs_num);
        if (ret)
                return ret;
        ret = of_property_read_u32(np, "fsl,channel", &data->channel);
        if (ret)
                return ret;

        /*
         * There is one output irq for each group of 64 inputs.
         * One register bit map can represent 32 input interrupts.
         */
        data->irq_count = DIV_ROUND_UP(irqs_num, 64);
        data->reg_num = irqs_num / 32;

        if (IS_ENABLED(CONFIG_PM)) {
                data->saved_reg = devm_kzalloc(&pdev->dev,
                                        sizeof(u32) * data->reg_num,
                                        GFP_KERNEL);
                if (!data->saved_reg)
                        return -ENOMEM;
        }

        ret = clk_prepare_enable(data->ipg_clk);
        if (ret) {
                dev_err(&pdev->dev, "failed to enable ipg clk: %d\n", ret);
                return ret;
        }

        /* steer all IRQs into configured channel */
        writel_relaxed(BIT(data->channel), data->regs + CHANCTRL);

        data->domain = irq_domain_create_linear(dev_fwnode(&pdev->dev), data->reg_num * 32,
                                                &imx_irqsteer_domain_ops, data);
        if (!data->domain) {
                dev_err(&pdev->dev, "failed to create IRQ domain\n");
                ret = -ENOMEM;
                goto out;
        }
        irq_domain_set_pm_device(data->domain, &pdev->dev);

        if (!data->irq_count || data->irq_count > CHAN_MAX_OUTPUT_INT) {
                ret = -EINVAL;
                goto out;
        }

        for (i = 0; i < data->irq_count; i++) {
                data->irq[i] = irq_of_parse_and_map(np, i);
                if (!data->irq[i])
                        break;

                irq_set_chained_handler_and_data(data->irq[i],
                                                 imx_irqsteer_irq_handler,
                                                 data);
        }

        platform_set_drvdata(pdev, data);

        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);

        return 0;
out:
        clk_disable_unprepare(data->ipg_clk);
        return ret;
}

static void imx_irqsteer_remove(struct platform_device *pdev)
{
        struct irqsteer_data *irqsteer_data = platform_get_drvdata(pdev);
        int i;

        for (i = 0; i < irqsteer_data->irq_count; i++) {
                if (!irqsteer_data->irq[i])
                        break;

                irq_set_chained_handler_and_data(irqsteer_data->irq[i],
                                                 NULL, NULL);
        }

        irq_domain_remove(irqsteer_data->domain);

        clk_disable_unprepare(irqsteer_data->ipg_clk);
}

#ifdef CONFIG_PM
static void imx_irqsteer_save_regs(struct irqsteer_data *data)
{
        int i;

        for (i = 0; i < data->reg_num; i++)
                data->saved_reg[i] = readl_relaxed(data->regs +
                                                CHANMASK(i, data->reg_num));
}

static void imx_irqsteer_restore_regs(struct irqsteer_data *data)
{
        int i;

        writel_relaxed(BIT(data->channel), data->regs + CHANCTRL);
        for (i = 0; i < data->reg_num; i++)
                writel_relaxed(data->saved_reg[i],
                               data->regs + CHANMASK(i, data->reg_num));
}

static int imx_irqsteer_suspend(struct device *dev)
{
        struct irqsteer_data *irqsteer_data = dev_get_drvdata(dev);

        imx_irqsteer_save_regs(irqsteer_data);
        clk_disable_unprepare(irqsteer_data->ipg_clk);

        return 0;
}

static int imx_irqsteer_resume(struct device *dev)
{
        struct irqsteer_data *irqsteer_data = dev_get_drvdata(dev);
        int ret;

        ret = clk_prepare_enable(irqsteer_data->ipg_clk);
        if (ret) {
                dev_err(dev, "failed to enable ipg clk: %d\n", ret);
                return ret;
        }
        imx_irqsteer_restore_regs(irqsteer_data);

        return 0;
}
#endif

static const struct dev_pm_ops imx_irqsteer_pm_ops = {
        SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
                                      pm_runtime_force_resume)
        SET_RUNTIME_PM_OPS(imx_irqsteer_suspend,
                           imx_irqsteer_resume, NULL)
};

static const struct of_device_id imx_irqsteer_dt_ids[] = {
        { .compatible = "fsl,imx-irqsteer", },
        {},
};

static struct platform_driver imx_irqsteer_driver = {
        .driver = {
                .name           = "imx-irqsteer",
                .of_match_table = imx_irqsteer_dt_ids,
                .pm             = &imx_irqsteer_pm_ops,
        },
        .probe          = imx_irqsteer_probe,
        .remove         = imx_irqsteer_remove,
};
builtin_platform_driver(imx_irqsteer_driver);