// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) STMicroelectronics 2020 - All Rights Reserved
 */
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rpmsg.h>
#include <linux/rpmsg/ns.h>
#include <linux/slab.h>

#include "rpmsg_internal.h"

/**
 * rpmsg_ns_register_device() - register name service device based on rpdev
 * @rpdev: prepared rpdev to be used for creating endpoints
 *
 * This function wraps rpmsg_register_device() preparing the rpdev for use as
 * basis for the rpmsg name service device.
 */
int rpmsg_ns_register_device(struct rpmsg_device *rpdev)
{
        rpdev->src = RPMSG_NS_ADDR;
        rpdev->dst = RPMSG_NS_ADDR;

        return rpmsg_register_device_override(rpdev, "rpmsg_ns");
}
EXPORT_SYMBOL(rpmsg_ns_register_device);

/* invoked when a name service announcement arrives */
static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
                       void *priv, u32 src)
{
        struct rpmsg_ns_msg *msg = data;
        struct rpmsg_device *newch;
        struct rpmsg_channel_info chinfo;
        struct device *dev = rpdev->dev.parent;
        int ret;

#if defined(CONFIG_DYNAMIC_DEBUG)
        dynamic_hex_dump("NS announcement: ", DUMP_PREFIX_NONE, 16, 1,
                         data, len, true);
#endif

        if (len != sizeof(*msg)) {
                dev_err(dev, "malformed ns msg (%d)\n", len);
                return -EINVAL;
        }

        /* don't trust the remote processor for null terminating the name */
        msg->name[RPMSG_NAME_SIZE - 1] = '\0';

        strscpy_pad(chinfo.name, msg->name, sizeof(chinfo.name));
        chinfo.src = RPMSG_ADDR_ANY;
        chinfo.dst = rpmsg32_to_cpu(rpdev, msg->addr);

        dev_info(dev, "%sing channel %s addr 0x%x\n",
                 rpmsg32_to_cpu(rpdev, msg->flags) & RPMSG_NS_DESTROY ?
                 "destroy" : "creat", msg->name, chinfo.dst);

        if (rpmsg32_to_cpu(rpdev, msg->flags) & RPMSG_NS_DESTROY) {
                ret = rpmsg_release_channel(rpdev, &chinfo);
                if (ret)
                        dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
        } else {
                newch = rpmsg_create_channel(rpdev, &chinfo);
                if (!newch)
                        dev_err(dev, "rpmsg_create_channel failed\n");
        }

        return 0;
}

static int rpmsg_ns_probe(struct rpmsg_device *rpdev)
{
        struct rpmsg_endpoint *ns_ept;
        struct rpmsg_channel_info ns_chinfo = {
                .src = RPMSG_NS_ADDR,
                .dst = RPMSG_NS_ADDR,
                .name = "name_service",
        };

        /*
         * Create the NS announcement service endpoint associated to the RPMsg
         * device. The endpoint will be automatically destroyed when the RPMsg
         * device will be deleted.
         */
        ns_ept = rpmsg_create_ept(rpdev, rpmsg_ns_cb, NULL, ns_chinfo);
        if (!ns_ept) {
                dev_err(&rpdev->dev, "failed to create the ns ept\n");
                return -ENOMEM;
        }
        rpdev->ept = ns_ept;

        return 0;
}

static struct rpmsg_driver rpmsg_ns_driver = {
        .drv.name = KBUILD_MODNAME,
        .probe = rpmsg_ns_probe,
};

static int rpmsg_ns_init(void)
{
        int ret;

        ret = register_rpmsg_driver(&rpmsg_ns_driver);
        if (ret < 0)
                pr_err("%s: Failed to register rpmsg driver\n", __func__);

        return ret;
}
postcore_initcall(rpmsg_ns_init);

static void rpmsg_ns_exit(void)
{
        unregister_rpmsg_driver(&rpmsg_ns_driver);
}
module_exit(rpmsg_ns_exit);

MODULE_DESCRIPTION("Name service announcement rpmsg driver");
MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
MODULE_LICENSE("GPL v2");