// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2022 MediaTek Corporation. All rights reserved.
 * Author: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
 */

#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/mailbox_controller.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

struct mtk_adsp_mbox_priv {
        struct device *dev;
        struct mbox_controller mbox;
        void __iomem *va_mboxreg;
        const struct mtk_adsp_mbox_cfg *cfg;
};

struct mtk_adsp_mbox_cfg {
        u32 set_in;
        u32 set_out;
        u32 clr_in;
        u32 clr_out;
};

static inline struct mtk_adsp_mbox_priv *get_mtk_adsp_mbox_priv(struct mbox_controller *mbox)
{
        return container_of(mbox, struct mtk_adsp_mbox_priv, mbox);
}

static irqreturn_t mtk_adsp_mbox_irq(int irq, void *data)
{
        struct mbox_chan *chan = data;
        struct mtk_adsp_mbox_priv *priv = get_mtk_adsp_mbox_priv(chan->mbox);
        u32 op = readl(priv->va_mboxreg + priv->cfg->set_out);

        writel(op, priv->va_mboxreg + priv->cfg->clr_out);

        return IRQ_WAKE_THREAD;
}

static irqreturn_t mtk_adsp_mbox_isr(int irq, void *data)
{
        struct mbox_chan *chan = data;

        mbox_chan_received_data(chan, NULL);

        return IRQ_HANDLED;
}

static struct mbox_chan *mtk_adsp_mbox_xlate(struct mbox_controller *mbox,
                                             const struct of_phandle_args *sp)
{
        return mbox->chans;
}

static int mtk_adsp_mbox_startup(struct mbox_chan *chan)
{
        struct mtk_adsp_mbox_priv *priv = get_mtk_adsp_mbox_priv(chan->mbox);

        /* Clear ADSP mbox command */
        writel(0xFFFFFFFF, priv->va_mboxreg + priv->cfg->clr_in);
        writel(0xFFFFFFFF, priv->va_mboxreg + priv->cfg->clr_out);

        return 0;
}

static void mtk_adsp_mbox_shutdown(struct mbox_chan *chan)
{
        struct mtk_adsp_mbox_priv *priv = get_mtk_adsp_mbox_priv(chan->mbox);

        /* Clear ADSP mbox command */
        writel(0xFFFFFFFF, priv->va_mboxreg + priv->cfg->clr_in);
        writel(0xFFFFFFFF, priv->va_mboxreg + priv->cfg->clr_out);
}

static int mtk_adsp_mbox_send_data(struct mbox_chan *chan, void *data)
{
        struct mtk_adsp_mbox_priv *priv = get_mtk_adsp_mbox_priv(chan->mbox);
        u32 *msg = data;

        writel(*msg, priv->va_mboxreg + priv->cfg->set_in);

        return 0;
}

static bool mtk_adsp_mbox_last_tx_done(struct mbox_chan *chan)
{
        struct mtk_adsp_mbox_priv *priv = get_mtk_adsp_mbox_priv(chan->mbox);

        return readl(priv->va_mboxreg + priv->cfg->set_in) == 0;
}

static const struct mbox_chan_ops mtk_adsp_mbox_chan_ops = {
        .send_data      = mtk_adsp_mbox_send_data,
        .startup        = mtk_adsp_mbox_startup,
        .shutdown       = mtk_adsp_mbox_shutdown,
        .last_tx_done   = mtk_adsp_mbox_last_tx_done,
};

static int mtk_adsp_mbox_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct mtk_adsp_mbox_priv *priv;
        const struct mtk_adsp_mbox_cfg *cfg;
        struct mbox_controller *mbox;
        int ret, irq;

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

        mbox = &priv->mbox;
        mbox->dev = dev;
        mbox->ops = &mtk_adsp_mbox_chan_ops;
        mbox->txdone_irq = false;
        mbox->txdone_poll = true;
        mbox->of_xlate = mtk_adsp_mbox_xlate;
        mbox->num_chans = 1;
        mbox->chans = devm_kzalloc(dev, sizeof(*mbox->chans), GFP_KERNEL);
        if (!mbox->chans)
                return -ENOMEM;

        priv->va_mboxreg = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(priv->va_mboxreg))
                return PTR_ERR(priv->va_mboxreg);

        cfg = of_device_get_match_data(dev);
        if (!cfg)
                return -EINVAL;
        priv->cfg = cfg;

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

        ret = devm_request_threaded_irq(dev, irq, mtk_adsp_mbox_irq,
                                        mtk_adsp_mbox_isr, IRQF_TRIGGER_NONE,
                                        dev_name(dev), mbox->chans);
        if (ret < 0)
                return ret;

        platform_set_drvdata(pdev, priv);

        return devm_mbox_controller_register(dev, &priv->mbox);
}

static const struct mtk_adsp_mbox_cfg mt8186_adsp_mbox_cfg = {
        .set_in         = 0x00,
        .set_out        = 0x04,
        .clr_in         = 0x08,
        .clr_out        = 0x0C,
};

static const struct mtk_adsp_mbox_cfg mt8195_adsp_mbox_cfg = {
        .set_in         = 0x00,
        .set_out        = 0x1c,
        .clr_in         = 0x04,
        .clr_out        = 0x20,
};

static const struct of_device_id mtk_adsp_mbox_of_match[] = {
        { .compatible = "mediatek,mt8186-adsp-mbox", .data = &mt8186_adsp_mbox_cfg },
        { .compatible = "mediatek,mt8195-adsp-mbox", .data = &mt8195_adsp_mbox_cfg },
        {},
};
MODULE_DEVICE_TABLE(of, mtk_adsp_mbox_of_match);

static struct platform_driver mtk_adsp_mbox_driver = {
        .probe          = mtk_adsp_mbox_probe,
        .driver = {
                .name   = "mtk_adsp_mbox",
                .of_match_table = mtk_adsp_mbox_of_match,
        },
};
module_platform_driver(mtk_adsp_mbox_driver);

MODULE_AUTHOR("Allen-KH Cheng <Allen-KH.Cheng@mediatek.com>");
MODULE_DESCRIPTION("MTK ADSP Mailbox Controller");
MODULE_LICENSE("GPL v2");