/*
 *
 * remote_config_server.c
 * Description:
 * remote_config over MRPC server driver
 *
 *
 * GPL LICENSE SUMMARY
 *
 *  Copyright(c) 2016-2018 Intel Corporation.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of version 2 of the GNU General Public License as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *  The full GNU General Public License is included in this distribution
 *  in the file called LICENSE.GPL.
 *
 *  Contact Information:
 *  Intel Corporation
 *  2200 Mission College Blvd.
 *  Santa Clara, CA  97052
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s:%d " fmt "\n", __func__, __LINE__

/************************************************/
/**                    Includes                 */
/************************************************/
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/byteorder/generic.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <linux/err.h>
#include <linux/netdevice.h>
#include <linux/ethtool.h>
#include <linux/mrpc.h>
#include <linux/remote_config_server.h>

#ifdef DEBUG
#define DBG(fmt, ...) pr_err(fmt, ##__VA_ARGS__)
#else
#define DBG(fmt, ...) pr_debug(fmt, ##__VA_ARGS__)
#endif

/* driver private database */
struct remote_config_private {
    struct platform_device *pdev;   /* platform device */
    struct mrpc_server *mrpc;       /* mrpc server handle */
    struct remote_config_funcs *callbacks;
};

struct remote_config_args {
    avalanche_pp_local_dev_addr_ioctl_params_t usr_params;
};

#define REMOTE_CONFIG_PROC(proc, func) \
    MRPC_PROCINFO_ENTRY(proc, func, sizeof(struct remote_config_args), sizeof(unsigned int))

enum {
    REMOTE_CONFIG_SET_DEV_ADDR = 0,
};

static struct remote_config_private *this;

static int mrpc_remote_config_proc(void *arg, ssize_t arglen, void *rep, ssize_t replen)
{
    struct remote_config_args       *p_arg  = (struct remote_config_args *)arg;
    struct remote_config_private    *priv   = this;
    unsigned int                    *reply  = (unsigned int*)rep;
    int                             ret     = 0;

    p_arg->usr_params.addr_type = be32_to_cpu(p_arg->usr_params.addr_type);
    p_arg->usr_params.op_type = be32_to_cpu(p_arg->usr_params.op_type);

    switch (p_arg->usr_params.addr_type)
    {
        /* MAC Address - no need to change endianity */
        case MTA_MAC_ADDR:
        case GW_MAC_ADDR:
        case LAN0_MAC_ADDR:
        case RND_MAC_ADDR:
        case WAN_MAC_ADDR:
            break;

        /* IPv4 - Change endianity */
        case MTA_RTP_IPV4_ADDR:
        case MTA_MNG_IPV4_ADDR:
        case MULTI_DROP_IPV4_ADDR:
        {
            p_arg->usr_params.u.ipv4 = be32_to_cpu(p_arg->usr_params.u.ipv4);
            break;
        }

        /* IPv6 - Change endianity */
        case MTA_RTP_IPV6_ADDR:
        case MTA_MNG_IPV6_ADDR:
        case MULTI_DROP_IPV6_ADDR:
        {
            p_arg->usr_params.u.ipv6[0] = be32_to_cpu(p_arg->usr_params.u.ipv6[0]);
            p_arg->usr_params.u.ipv6[1] = be32_to_cpu(p_arg->usr_params.u.ipv6[1]);
            p_arg->usr_params.u.ipv6[2] = be32_to_cpu(p_arg->usr_params.u.ipv6[2]);
            p_arg->usr_params.u.ipv6[3] = be32_to_cpu(p_arg->usr_params.u.ipv6[3]);
            break;
        }

        default:
        {
            pr_err("ERROR: mrpc remote_config not initialized");
            return -1;
        }
    }

    *reply = (unsigned int)priv->callbacks->avalanche_pp_local_dev_addr(&p_arg->usr_params);

    return ret;
}

static struct mrpc_procinfo remote_config_server_procs[] = {
    REMOTE_CONFIG_PROC(REMOTE_CONFIG_SET_DEV_ADDR, mrpc_remote_config_proc),
};

/* sysfs for future use */
static ssize_t status_show(struct device *dev,
                           struct device_attribute *attr, char *buf)
{
    struct remote_config_private *priv = dev_get_drvdata(dev);

    if (!priv)
        return -EINVAL;

    return scnprintf(buf, PAGE_SIZE, "status ok");
}

static DEVICE_ATTR(status, S_IRUGO, status_show, NULL);

static struct attribute *remote_config_attrs[] = {
    &dev_attr_status.attr,
    NULL
};

static struct attribute_group remote_config_attrs_group = {
    .attrs = remote_config_attrs,
};

/**
 * mrpc_remote_config_server_unregister
 *
 * unregister remote_config callbacks
 *
 * @return 0 for success, error code otherwise
 */
void mrpc_remote_config_server_unregister(void)
{
    BUG_ON(!this);
    BUG_ON(!this->callbacks);

    kfree(this->callbacks);
    this->callbacks = NULL;

    pr_info("callback functions unregistered\n");
}
EXPORT_SYMBOL(mrpc_remote_config_server_unregister);

/**
 * mrpc_remote_config_server_register
 *
 * register remote_config callbacks
 *
 * @param remote_config_funcs   callback functions
 *
 * @return 0 for success, error code otherwise
 */
int mrpc_remote_config_server_register(struct remote_config_funcs *callbacks)
{
    BUG_ON(!this);
    BUG_ON(!callbacks);
    BUG_ON(this->callbacks);

    this->callbacks = kzalloc(sizeof(*callbacks), GFP_KERNEL);
    if (!this->callbacks) {
        pr_err("Failed to allocate memory");
        return -ENOMEM;
    }

    memcpy(this->callbacks, callbacks, sizeof(*callbacks));

    pr_info("callback functions registered");
    return 0;
}
EXPORT_SYMBOL(mrpc_remote_config_server_register);

/**
 * remote_config_probe
 *
 * @param pdev   platform device
 *
 * @return 0 for success, error code otherwise
 */
static int remote_config_probe(struct platform_device *pdev)
{
    struct remote_config_private *priv;
    int ret;

    priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
    if (!priv) {
        pr_err("memory allocation failed");
        return -ENOMEM;
    }

    dev_set_drvdata(&pdev->dev, priv);
    priv->pdev = pdev;

    ret = sysfs_create_group(&priv->pdev->dev.kobj, &remote_config_attrs_group);
    if (ret) {
        pr_err("sysfs_create_group failed (ret=%d)", ret);
        return ret;
    }

    priv->mrpc = mrpc_server_register(MRPC_RESERVED_ID_REMOTE_CONFIG,
                                      "Remote Config",
                                      remote_config_server_procs,
                                      ARRAY_SIZE(remote_config_server_procs));
    if (!priv->mrpc) {
        pr_err("failed to register remote_config");
        ret = -ENODEV;
        goto out_remove_group;
    }

    this = priv;
    return 0;

out_remove_group:
    sysfs_remove_group(&priv->pdev->dev.kobj, &remote_config_attrs_group);
    return ret;
}

/**
 * remote_config_remove
 *
 * This function is called when the remote_config driver is
 * removed.
 *
 * @param pdev   platform device
 *
 * @return 0 for success, error code otherwise
 */
static int remote_config_remove(struct platform_device *pdev)
{
    struct remote_config_private *priv = platform_get_drvdata(pdev);

    if (priv->callbacks)
        kfree(priv->callbacks);
    mrpc_server_unregister(priv->mrpc);
    sysfs_remove_group(&priv->pdev->dev.kobj, &remote_config_attrs_group);
    dev_set_drvdata(&pdev->dev, NULL);
    this = NULL;

    return 0;
}

static struct platform_driver remote_config_driver = {
    .driver = {
        .name   = "remote_config_mrpc_server",
    },
    .probe = remote_config_probe,
    .remove = remote_config_remove,
};

static struct platform_device *remote_config_device;

static int remote_config_server_init(void)
{
    int ret;

    printk("remote_config_server_init: remote_config_args_size=%d\n", sizeof(struct remote_config_args));
    ret = platform_driver_register(&remote_config_driver);
    if (ret < 0) {
        pr_err("Failed to register remote_config platform driver: %d\n", ret);
        return ret;
    }

    pr_debug("remote config server platform driver is registered");

    remote_config_device = platform_device_register_simple("remote_config_mrpc_server", -1, NULL, 0);
    if (IS_ERR(remote_config_device)) {
        pr_err("Failed to register remote_config platform device\n");
        platform_driver_unregister(&remote_config_driver);
        return PTR_ERR(remote_config_device);
    }

    dev_info(&remote_config_device->dev, "platform device is registered\n");

    return 0;
}

static void __exit remote_config_server_exit(void)
{
    platform_device_unregister(remote_config_device);
    platform_driver_unregister(&remote_config_driver);
}

/******************************************************/
/**    Module Declarations                           **/
/******************************************************/
static_notifier_module_init(mrpc_ready, remote_config_server_init);
module_exit(remote_config_server_exit);

MODULE_AUTHOR("Intel Corporation");
MODULE_AUTHOR("Ofir Bitton ofir1.bitton@intel.com");
MODULE_DESCRIPTION("remote_config mrpc server");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.0");