// SPDX-License-Identifier: GPL-2.0
/*
 * Platform driver for CDX bus.
 *
 * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
 */

#include <linux/rpmsg.h>
#include <linux/remoteproc.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/cdx/cdx_bus.h>
#include <linux/module.h>

#include "../cdx.h"
#include "cdx_controller.h"
#include "mcdi_functions.h"
#include "mcdid.h"

static struct rpmsg_device_id cdx_rpmsg_id_table[] = {
        { .name = "mcdi_ipc" },
        { },
};
MODULE_DEVICE_TABLE(rpmsg, cdx_rpmsg_id_table);

int cdx_rpmsg_send(struct cdx_mcdi *cdx_mcdi,
                   const struct cdx_dword *hdr, size_t hdr_len,
                   const struct cdx_dword *sdu, size_t sdu_len)
{
        unsigned char *send_buf;
        int ret;

        send_buf = kzalloc(hdr_len + sdu_len, GFP_KERNEL);
        if (!send_buf)
                return -ENOMEM;

        memcpy(send_buf, hdr, hdr_len);
        memcpy(send_buf + hdr_len, sdu, sdu_len);

        ret = rpmsg_send(cdx_mcdi->ept, send_buf, hdr_len + sdu_len);
        kfree(send_buf);

        return ret;
}

static int cdx_attach_to_rproc(struct platform_device *pdev)
{
        struct device_node *r5_core_node;
        struct cdx_controller *cdx_c;
        struct cdx_mcdi *cdx_mcdi;
        struct device *dev;
        struct rproc *rp;
        int ret;

        dev = &pdev->dev;
        cdx_c = platform_get_drvdata(pdev);
        cdx_mcdi = cdx_c->priv;

        r5_core_node = of_parse_phandle(dev->of_node, "xlnx,rproc", 0);
        if (!r5_core_node) {
                dev_err(&pdev->dev, "xlnx,rproc: invalid phandle\n");
                return -EINVAL;
        }

        rp = rproc_get_by_phandle(r5_core_node->phandle);
        if (!rp) {
                ret = -EPROBE_DEFER;
                goto pdev_err;
        }

        /* Attach to remote processor */
        ret = rproc_boot(rp);
        if (ret) {
                dev_err(&pdev->dev, "Failed to attach to remote processor\n");
                rproc_put(rp);
                goto pdev_err;
        }

        cdx_mcdi->r5_rproc = rp;
pdev_err:
        of_node_put(r5_core_node);
        return ret;
}

static void cdx_detach_to_r5(struct platform_device *pdev)
{
        struct cdx_controller *cdx_c;
        struct cdx_mcdi *cdx_mcdi;

        cdx_c = platform_get_drvdata(pdev);
        cdx_mcdi = cdx_c->priv;

        rproc_detach(cdx_mcdi->r5_rproc);
        rproc_put(cdx_mcdi->r5_rproc);
}

static int cdx_rpmsg_cb(struct rpmsg_device *rpdev, void *data,
                        int len, void *priv, u32 src)
{
        struct cdx_controller *cdx_c = dev_get_drvdata(&rpdev->dev);
        struct cdx_mcdi *cdx_mcdi = cdx_c->priv;

        if (len > MCDI_BUF_LEN)
                return -EINVAL;

        cdx_mcdi_process_cmd(cdx_mcdi, (struct cdx_dword *)data, len);

        return 0;
}

static void cdx_rpmsg_post_probe_work(struct work_struct *work)
{
        struct cdx_controller *cdx_c;
        struct cdx_mcdi *cdx_mcdi;

        cdx_mcdi = container_of(work, struct cdx_mcdi, work);
        cdx_c = dev_get_drvdata(&cdx_mcdi->rpdev->dev);
        cdx_rpmsg_post_probe(cdx_c);
}

static int cdx_rpmsg_probe(struct rpmsg_device *rpdev)
{
        struct rpmsg_channel_info chinfo = {0};
        struct cdx_controller *cdx_c;
        struct cdx_mcdi *cdx_mcdi;

        cdx_c = (struct cdx_controller *)cdx_rpmsg_id_table[0].driver_data;
        cdx_mcdi = cdx_c->priv;

        chinfo.src = RPMSG_ADDR_ANY;
        chinfo.dst = rpdev->dst;
        strscpy(chinfo.name, cdx_rpmsg_id_table[0].name, sizeof(chinfo.name));

        cdx_mcdi->ept = rpmsg_create_ept(rpdev, cdx_rpmsg_cb, NULL, chinfo);
        if (!cdx_mcdi->ept) {
                dev_err_probe(&rpdev->dev, -ENXIO,
                              "Failed to create ept for channel %s\n",
                              chinfo.name);
                return -EINVAL;
        }

        cdx_mcdi->rpdev = rpdev;
        dev_set_drvdata(&rpdev->dev, cdx_c);

        schedule_work(&cdx_mcdi->work);
        return 0;
}

static void cdx_rpmsg_remove(struct rpmsg_device *rpdev)
{
        struct cdx_controller *cdx_c = dev_get_drvdata(&rpdev->dev);
        struct cdx_mcdi *cdx_mcdi = cdx_c->priv;

        flush_work(&cdx_mcdi->work);
        cdx_rpmsg_pre_remove(cdx_c);

        rpmsg_destroy_ept(cdx_mcdi->ept);
        dev_set_drvdata(&rpdev->dev, NULL);
}

static struct rpmsg_driver cdx_rpmsg_driver = {
        .drv.name = KBUILD_MODNAME,
        .id_table = cdx_rpmsg_id_table,
        .probe = cdx_rpmsg_probe,
        .remove = cdx_rpmsg_remove,
        .callback = cdx_rpmsg_cb,
};

int cdx_setup_rpmsg(struct platform_device *pdev)
{
        struct cdx_controller *cdx_c;
        struct cdx_mcdi *cdx_mcdi;
        int ret;

        /* Attach to remote processor */
        ret = cdx_attach_to_rproc(pdev);
        if (ret)
                return ret;

        cdx_c = platform_get_drvdata(pdev);
        cdx_mcdi = cdx_c->priv;

        /* Register RPMsg driver */
        cdx_rpmsg_id_table[0].driver_data = (kernel_ulong_t)cdx_c;

        INIT_WORK(&cdx_mcdi->work, cdx_rpmsg_post_probe_work);
        ret = register_rpmsg_driver(&cdx_rpmsg_driver);
        if (ret) {
                dev_err(&pdev->dev,
                        "Failed to register cdx RPMsg driver: %d\n", ret);
                cdx_detach_to_r5(pdev);
        }

        return ret;
}

void cdx_destroy_rpmsg(struct platform_device *pdev)
{
        unregister_rpmsg_driver(&cdx_rpmsg_driver);

        cdx_detach_to_r5(pdev);
}