/*
 * Copyright (C) 2007-2012 Siemens AG
 *
 * Written by:
 * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>

#include <net/netlink.h>
#include <net/nl802154.h>
#include <net/mac802154.h>
#include <net/ieee802154_netdev.h>
#include <net/route.h>
#include <net/cfg802154.h>

#include "ieee802154_i.h"
#include "cfg.h"

static void ieee802154_tasklet_handler(unsigned long data)
{
        struct ieee802154_local *local = (struct ieee802154_local *)data;
        struct sk_buff *skb;

        while ((skb = skb_dequeue(&local->skb_queue))) {
                switch (skb->pkt_type) {
                case IEEE802154_RX_MSG:
                        /* Clear skb->pkt_type in order to not confuse kernel
                         * netstack.
                         */
                        skb->pkt_type = 0;
                        ieee802154_rx(local, skb);
                        break;
                default:
                        WARN(1, "mac802154: Packet is of unknown type %d\n",
                             skb->pkt_type);
                        kfree_skb(skb);
                        break;
                }
        }
}

struct ieee802154_hw *
ieee802154_alloc_hw(size_t priv_data_len, const struct ieee802154_ops *ops)
{
        struct wpan_phy *phy;
        struct ieee802154_local *local;
        size_t priv_size;

        if (WARN_ON(!ops || !(ops->xmit_async || ops->xmit_sync) || !ops->ed ||
                    !ops->start || !ops->stop || !ops->set_channel))
                return NULL;

        /* Ensure 32-byte alignment of our private data and hw private data.
         * We use the wpan_phy priv data for both our ieee802154_local and for
         * the driver's private data
         *
         * in memory it'll be like this:
         *
         * +-------------------------+
         * | struct wpan_phy         |
         * +-------------------------+
         * | struct ieee802154_local |
         * +-------------------------+
         * | driver's private data   |
         * +-------------------------+
         *
         * Due to ieee802154 layer isn't aware of driver and MAC structures,
         * so lets align them here.
         */

        priv_size = ALIGN(sizeof(*local), NETDEV_ALIGN) + priv_data_len;

        phy = wpan_phy_new(&mac802154_config_ops, priv_size);
        if (!phy) {
                pr_err("failure to allocate master IEEE802.15.4 device\n");
                return NULL;
        }

        phy->privid = mac802154_wpan_phy_privid;

        local = wpan_phy_priv(phy);
        local->phy = phy;
        local->hw.phy = local->phy;
        local->hw.priv = (char *)local + ALIGN(sizeof(*local), NETDEV_ALIGN);
        local->ops = ops;

        INIT_LIST_HEAD(&local->interfaces);
        mutex_init(&local->iflist_mtx);

        tasklet_init(&local->tasklet,
                     ieee802154_tasklet_handler,
                     (unsigned long)local);

        skb_queue_head_init(&local->skb_queue);

        INIT_WORK(&local->tx_work, ieee802154_xmit_worker);

        /* init supported flags with 802.15.4 default ranges */
        phy->supported.max_minbe = 8;
        phy->supported.min_maxbe = 3;
        phy->supported.max_maxbe = 8;
        phy->supported.min_frame_retries = 0;
        phy->supported.max_frame_retries = 7;
        phy->supported.max_csma_backoffs = 5;
        phy->supported.lbt = NL802154_SUPPORTED_BOOL_FALSE;

        /* always supported */
        phy->supported.iftypes = BIT(NL802154_IFTYPE_NODE);

        return &local->hw;
}
EXPORT_SYMBOL(ieee802154_alloc_hw);

void ieee802154_free_hw(struct ieee802154_hw *hw)
{
        struct ieee802154_local *local = hw_to_local(hw);

        BUG_ON(!list_empty(&local->interfaces));

        mutex_destroy(&local->iflist_mtx);

        wpan_phy_free(local->phy);
}
EXPORT_SYMBOL(ieee802154_free_hw);

static void ieee802154_setup_wpan_phy_pib(struct wpan_phy *wpan_phy)
{
        /* TODO warn on empty symbol_duration
         * Should be done when all drivers sets this value.
         */

        wpan_phy->lifs_period = IEEE802154_LIFS_PERIOD *
                                wpan_phy->symbol_duration;
        wpan_phy->sifs_period = IEEE802154_SIFS_PERIOD *
                                wpan_phy->symbol_duration;
}

int ieee802154_register_hw(struct ieee802154_hw *hw)
{
        struct ieee802154_local *local = hw_to_local(hw);
        struct net_device *dev;
        int rc = -ENOSYS;

        local->workqueue =
                create_singlethread_workqueue(wpan_phy_name(local->phy));
        if (!local->workqueue) {
                rc = -ENOMEM;
                goto out;
        }

        hrtimer_init(&local->ifs_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        local->ifs_timer.function = ieee802154_xmit_ifs_timer;

        wpan_phy_set_dev(local->phy, local->hw.parent);

        ieee802154_setup_wpan_phy_pib(local->phy);

        if (!(hw->flags & IEEE802154_HW_CSMA_PARAMS)) {
                local->phy->supported.min_csma_backoffs = 4;
                local->phy->supported.max_csma_backoffs = 4;
                local->phy->supported.min_maxbe = 5;
                local->phy->supported.max_maxbe = 5;
                local->phy->supported.min_minbe = 3;
                local->phy->supported.max_minbe = 3;
        }

        if (!(hw->flags & IEEE802154_HW_FRAME_RETRIES)) {
                local->phy->supported.min_frame_retries = 3;
                local->phy->supported.max_frame_retries = 3;
        }

        if (hw->flags & IEEE802154_HW_PROMISCUOUS)
                local->phy->supported.iftypes |= BIT(NL802154_IFTYPE_MONITOR);

        rc = wpan_phy_register(local->phy);
        if (rc < 0)
                goto out_wq;

        rtnl_lock();

        dev = ieee802154_if_add(local, "wpan%d", NET_NAME_ENUM,
                                NL802154_IFTYPE_NODE,
                                cpu_to_le64(0x0000000000000000ULL));
        if (IS_ERR(dev)) {
                rtnl_unlock();
                rc = PTR_ERR(dev);
                goto out_phy;
        }

        rtnl_unlock();

        return 0;

out_phy:
        wpan_phy_unregister(local->phy);
out_wq:
        destroy_workqueue(local->workqueue);
out:
        return rc;
}
EXPORT_SYMBOL(ieee802154_register_hw);

void ieee802154_unregister_hw(struct ieee802154_hw *hw)
{
        struct ieee802154_local *local = hw_to_local(hw);

        tasklet_kill(&local->tasklet);
        flush_workqueue(local->workqueue);

        rtnl_lock();

        ieee802154_remove_interfaces(local);

        rtnl_unlock();

        destroy_workqueue(local->workqueue);
        wpan_phy_unregister(local->phy);
}
EXPORT_SYMBOL(ieee802154_unregister_hw);

static int __init ieee802154_init(void)
{
        return ieee802154_iface_init();
}

static void __exit ieee802154_exit(void)
{
        ieee802154_iface_exit();

        rcu_barrier();
}

subsys_initcall(ieee802154_init);
module_exit(ieee802154_exit);

MODULE_DESCRIPTION("IEEE 802.15.4 subsystem");
MODULE_LICENSE("GPL v2");