/*
 * Loopback IEEE 802.15.4 interface
 *
 * Copyright 2007-2012 Siemens AG
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Written by:
 * Sergey Lapin <slapin@ossfans.org>
 * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
 * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
 */

#include <linux/module.h>
#include <linux/timer.h>
#include <linux/platform_device.h>
#include <linux/netdevice.h>
#include <linux/spinlock.h>
#include <net/mac802154.h>
#include <net/wpan-phy.h>

static int numlbs = 1;

struct fakelb_dev_priv {
        struct ieee802154_dev *dev;

        struct list_head list;
        struct fakelb_priv *fake;

        spinlock_t lock;
        bool working;
};

struct fakelb_priv {
        struct list_head list;
        rwlock_t lock;
};

static int
fakelb_hw_ed(struct ieee802154_dev *dev, u8 *level)
{
        might_sleep();
        BUG_ON(!level);
        *level = 0xbe;

        return 0;
}

static int
fakelb_hw_channel(struct ieee802154_dev *dev, int page, int channel)
{
        pr_debug("set channel to %d\n", channel);

        might_sleep();
        dev->phy->current_page = page;
        dev->phy->current_channel = channel;

        return 0;
}

static void
fakelb_hw_deliver(struct fakelb_dev_priv *priv, struct sk_buff *skb)
{
        struct sk_buff *newskb;

        spin_lock(&priv->lock);
        if (priv->working) {
                newskb = pskb_copy(skb, GFP_ATOMIC);
                ieee802154_rx_irqsafe(priv->dev, newskb, 0xcc);
        }
        spin_unlock(&priv->lock);
}

static int
fakelb_hw_xmit(struct ieee802154_dev *dev, struct sk_buff *skb)
{
        struct fakelb_dev_priv *priv = dev->priv;
        struct fakelb_priv *fake = priv->fake;

        might_sleep();

        read_lock_bh(&fake->lock);
        if (priv->list.next == priv->list.prev) {
                /* we are the only one device */
                fakelb_hw_deliver(priv, skb);
        } else {
                struct fakelb_dev_priv *dp;
                list_for_each_entry(dp, &priv->fake->list, list) {
                        if (dp != priv &&
                            (dp->dev->phy->current_channel ==
                             priv->dev->phy->current_channel))
                                fakelb_hw_deliver(dp, skb);
                }
        }
        read_unlock_bh(&fake->lock);

        return 0;
}

static int
fakelb_hw_start(struct ieee802154_dev *dev) {
        struct fakelb_dev_priv *priv = dev->priv;
        int ret = 0;

        spin_lock(&priv->lock);
        if (priv->working)
                ret = -EBUSY;
        else
                priv->working = 1;
        spin_unlock(&priv->lock);

        return ret;
}

static void
fakelb_hw_stop(struct ieee802154_dev *dev) {
        struct fakelb_dev_priv *priv = dev->priv;

        spin_lock(&priv->lock);
        priv->working = 0;
        spin_unlock(&priv->lock);
}

static struct ieee802154_ops fakelb_ops = {
        .owner = THIS_MODULE,
        .xmit = fakelb_hw_xmit,
        .ed = fakelb_hw_ed,
        .set_channel = fakelb_hw_channel,
        .start = fakelb_hw_start,
        .stop = fakelb_hw_stop,
};

/* Number of dummy devices to be set up by this module. */
module_param(numlbs, int, 0);
MODULE_PARM_DESC(numlbs, " number of pseudo devices");

static int fakelb_add_one(struct device *dev, struct fakelb_priv *fake)
{
        struct fakelb_dev_priv *priv;
        int err;
        struct ieee802154_dev *ieee;

        ieee = ieee802154_alloc_device(sizeof(*priv), &fakelb_ops);
        if (!ieee)
                return -ENOMEM;

        priv = ieee->priv;
        priv->dev = ieee;

        /* 868 MHz BPSK 802.15.4-2003 */
        ieee->phy->channels_supported[0] |= 1;
        /* 915 MHz BPSK 802.15.4-2003 */
        ieee->phy->channels_supported[0] |= 0x7fe;
        /* 2.4 GHz O-QPSK 802.15.4-2003 */
        ieee->phy->channels_supported[0] |= 0x7FFF800;
        /* 868 MHz ASK 802.15.4-2006 */
        ieee->phy->channels_supported[1] |= 1;
        /* 915 MHz ASK 802.15.4-2006 */
        ieee->phy->channels_supported[1] |= 0x7fe;
        /* 868 MHz O-QPSK 802.15.4-2006 */
        ieee->phy->channels_supported[2] |= 1;
        /* 915 MHz O-QPSK 802.15.4-2006 */
        ieee->phy->channels_supported[2] |= 0x7fe;
        /* 2.4 GHz CSS 802.15.4a-2007 */
        ieee->phy->channels_supported[3] |= 0x3fff;
        /* UWB Sub-gigahertz 802.15.4a-2007 */
        ieee->phy->channels_supported[4] |= 1;
        /* UWB Low band 802.15.4a-2007 */
        ieee->phy->channels_supported[4] |= 0x1e;
        /* UWB High band 802.15.4a-2007 */
        ieee->phy->channels_supported[4] |= 0xffe0;
        /* 750 MHz O-QPSK 802.15.4c-2009 */
        ieee->phy->channels_supported[5] |= 0xf;
        /* 750 MHz MPSK 802.15.4c-2009 */
        ieee->phy->channels_supported[5] |= 0xf0;
        /* 950 MHz BPSK 802.15.4d-2009 */
        ieee->phy->channels_supported[6] |= 0x3ff;
        /* 950 MHz GFSK 802.15.4d-2009 */
        ieee->phy->channels_supported[6] |= 0x3ffc00;

        INIT_LIST_HEAD(&priv->list);
        priv->fake = fake;

        spin_lock_init(&priv->lock);

        ieee->parent = dev;

        err = ieee802154_register_device(ieee);
        if (err)
                goto err_reg;

        write_lock_bh(&fake->lock);
        list_add_tail(&priv->list, &fake->list);
        write_unlock_bh(&fake->lock);

        return 0;

err_reg:
        ieee802154_free_device(priv->dev);
        return err;
}

static void fakelb_del(struct fakelb_dev_priv *priv)
{
        write_lock_bh(&priv->fake->lock);
        list_del(&priv->list);
        write_unlock_bh(&priv->fake->lock);

        ieee802154_unregister_device(priv->dev);
        ieee802154_free_device(priv->dev);
}

static int fakelb_probe(struct platform_device *pdev)
{
        struct fakelb_priv *priv;
        struct fakelb_dev_priv *dp;
        int err = -ENOMEM;
        int i;

        priv = kzalloc(sizeof(struct fakelb_priv), GFP_KERNEL);
        if (!priv)
                goto err_alloc;

        INIT_LIST_HEAD(&priv->list);
        rwlock_init(&priv->lock);

        for (i = 0; i < numlbs; i++) {
                err = fakelb_add_one(&pdev->dev, priv);
                if (err < 0)
                        goto err_slave;
        }

        platform_set_drvdata(pdev, priv);
        dev_info(&pdev->dev, "added ieee802154 hardware\n");
        return 0;

err_slave:
        list_for_each_entry(dp, &priv->list, list)
                fakelb_del(dp);
        kfree(priv);
err_alloc:
        return err;
}

static int fakelb_remove(struct platform_device *pdev)
{
        struct fakelb_priv *priv = platform_get_drvdata(pdev);
        struct fakelb_dev_priv *dp, *temp;

        list_for_each_entry_safe(dp, temp, &priv->list, list)
                fakelb_del(dp);
        kfree(priv);

        return 0;
}

static struct platform_device *ieee802154fake_dev;

static struct platform_driver ieee802154fake_driver = {
        .probe = fakelb_probe,
        .remove = fakelb_remove,
        .driver = {
                        .name = "ieee802154fakelb",
                        .owner = THIS_MODULE,
        },
};

static __init int fakelb_init_module(void)
{
        ieee802154fake_dev = platform_device_register_simple(
                             "ieee802154fakelb", -1, NULL, 0);
        return platform_driver_register(&ieee802154fake_driver);
}

static __exit void fake_remove_module(void)
{
        platform_driver_unregister(&ieee802154fake_driver);
        platform_device_unregister(ieee802154fake_dev);
}

module_init(fakelb_init_module);
module_exit(fake_remove_module);
MODULE_LICENSE("GPL");