/*
   * Copyright (C) 2007-2012 Siemens AG
   *
   * Written by:
   * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
   *
   * Based on the code from 'linux-zigbee.sourceforge.net' project.
   *
   * 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.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/netdevice.h>
  
  #include <net/netlink.h>
  #include <linux/nl802154.h>
  #include <net/mac802154.h>
  #include <net/route.h>
  #include <net/wpan-phy.h>
  
  #include "mac802154.h"
  
  int mac802154_slave_open(struct net_device *dev)
  {
  	struct mac802154_sub_if_data *priv = netdev_priv(dev);
  	struct mac802154_priv *ipriv = priv->hw;
  	int res = 0;
  
  	if (ipriv->open_count++ == 0) {
  		res = ipriv->ops->start(&ipriv->hw);
  		WARN_ON(res);
  		if (res)
  			goto err;
  	}
  
  	if (ipriv->ops->ieee_addr) {
  		res = ipriv->ops->ieee_addr(&ipriv->hw, dev->dev_addr);
  		WARN_ON(res);
  		if (res)
  			goto err;
  		mac802154_dev_set_ieee_addr(dev);
  	}
  
  	netif_start_queue(dev);
  	return 0;
  err:
  	priv->hw->open_count--;
  
  	return res;
  }
  
  int mac802154_slave_close(struct net_device *dev)
  {
  	struct mac802154_sub_if_data *priv = netdev_priv(dev);
  	struct mac802154_priv *ipriv = priv->hw;
  
  	netif_stop_queue(dev);
  
  	if (!--ipriv->open_count)
  		ipriv->ops->stop(&ipriv->hw);
  
  	return 0;
  }
  
  static int
  mac802154_netdev_register(struct wpan_phy *phy, struct net_device *dev)
  {
  	struct mac802154_sub_if_data *priv;
  	struct mac802154_priv *ipriv;
  	int err;
  
  	ipriv = wpan_phy_priv(phy);
  
  	priv = netdev_priv(dev);
  	priv->dev = dev;
  	priv->hw = ipriv;
  
  	dev->needed_headroom = ipriv->hw.extra_tx_headroom;
  
  	SET_NETDEV_DEV(dev, &ipriv->phy->dev);
  
  	mutex_lock(&ipriv->slaves_mtx);
  	if (!ipriv->running) {
  		mutex_unlock(&ipriv->slaves_mtx);
  		return -ENODEV;
  	}
  	mutex_unlock(&ipriv->slaves_mtx);
  
  	err = register_netdev(dev);
  	if (err < 0)
  		return err;
  
  	rtnl_lock();
  	mutex_lock(&ipriv->slaves_mtx);
  	list_add_tail_rcu(&priv->list, &ipriv->slaves);
  	mutex_unlock(&ipriv->slaves_mtx);
  	rtnl_unlock();
  
  	return 0;
  }
  
  static void
  mac802154_del_iface(struct wpan_phy *phy, struct net_device *dev)
  {
  	struct mac802154_sub_if_data *sdata;
  	ASSERT_RTNL();
  
  	sdata = netdev_priv(dev);
  
  	BUG_ON(sdata->hw->phy != phy);
  
  	mutex_lock(&sdata->hw->slaves_mtx);
  	list_del_rcu(&sdata->list);
  	mutex_unlock(&sdata->hw->slaves_mtx);
  
  	synchronize_rcu();
  	unregister_netdevice(sdata->dev);
  }
  
  static struct net_device *
  mac802154_add_iface(struct wpan_phy *phy, const char *name, int type)
  {
  	struct net_device *dev;
  	int err = -ENOMEM;
  
  	switch (type) {
  	case IEEE802154_DEV_MONITOR:
  		dev = alloc_netdev(sizeof(struct mac802154_sub_if_data),
  				   name, mac802154_monitor_setup);
  		break;
  	case IEEE802154_DEV_WPAN:
  		dev = alloc_netdev(sizeof(struct mac802154_sub_if_data),
  				   name, mac802154_wpan_setup);
  		break;
  	default:
  		dev = NULL;
  		err = -EINVAL;
  		break;
  	}
  	if (!dev)
  		goto err;
  
  	err = mac802154_netdev_register(phy, dev);
  	if (err)
  		goto err_free;
  
  	dev_hold(dev); /* we return an incremented device refcount */
  	return dev;
  
  err_free:
  	free_netdev(dev);
  err:
  	return ERR_PTR(err);
  }
  
  struct ieee802154_dev *
  ieee802154_alloc_device(size_t priv_data_len, struct ieee802154_ops *ops)
  {
  	struct wpan_phy *phy;
  	struct mac802154_priv *priv;
  	size_t priv_size;
  
  	if (!ops || !ops->xmit || !ops->ed || !ops->start ||
  	    !ops->stop || !ops->set_channel) {
  		pr_err("undefined IEEE802.15.4 device operations
  ");
  		return NULL;
  	}
  
  	/* Ensure 32-byte alignment of our private data and hw private data.
  	 * We use the wpan_phy priv data for both our mac802154_priv and for
  	 * the driver's private data
  	 *
  	 * in memory it'll be like this:
  	 *
  	 * +-----------------------+
  	 * | struct wpan_phy       |
  	 * +-----------------------+
  	 * | struct mac802154_priv |
  	 * +-----------------------+
  	 * | driver's private data |
  	 * +-----------------------+
  	 *
  	 * Due to ieee802154 layer isn't aware of driver and MAC structures,
  	 * so lets allign them here.
  	 */
  
  	priv_size = ALIGN(sizeof(*priv), NETDEV_ALIGN) + priv_data_len;
  
  	phy = wpan_phy_alloc(priv_size);
  	if (!phy) {
  		pr_err("failure to allocate master IEEE802.15.4 device
  ");
  		return NULL;
  	}
  
  	priv = wpan_phy_priv(phy);
  	priv->hw.phy = priv->phy = phy;
  	priv->hw.priv = (char *)priv + ALIGN(sizeof(*priv), NETDEV_ALIGN);
  	priv->ops = ops;
  
  	INIT_LIST_HEAD(&priv->slaves);
  	mutex_init(&priv->slaves_mtx);
  
  	return &priv->hw;
  }
  EXPORT_SYMBOL(ieee802154_alloc_device);
  
  void ieee802154_free_device(struct ieee802154_dev *hw)
  {
  	struct mac802154_priv *priv = mac802154_to_priv(hw);
  
  	BUG_ON(!list_empty(&priv->slaves));
  
  	mutex_destroy(&priv->slaves_mtx);
  
  	wpan_phy_free(priv->phy);
  }
  EXPORT_SYMBOL(ieee802154_free_device);
  
  int ieee802154_register_device(struct ieee802154_dev *dev)
  {
  	struct mac802154_priv *priv = mac802154_to_priv(dev);
  	int rc = -ENOMEM;
  
  	priv->dev_workqueue =
  		create_singlethread_workqueue(wpan_phy_name(priv->phy));
  	if (!priv->dev_workqueue)
  		goto out;
  
  	wpan_phy_set_dev(priv->phy, priv->hw.parent);
  
  	priv->phy->add_iface = mac802154_add_iface;
  	priv->phy->del_iface = mac802154_del_iface;
  
  	rc = wpan_phy_register(priv->phy);
  	if (rc < 0)
  		goto out_wq;
  
  	rtnl_lock();
  
  	mutex_lock(&priv->slaves_mtx);
  	priv->running = MAC802154_DEVICE_RUN;
  	mutex_unlock(&priv->slaves_mtx);
  
  	rtnl_unlock();
  
  	return 0;
  
  out_wq:
  	destroy_workqueue(priv->dev_workqueue);
  out:
  	return rc;
  }
  EXPORT_SYMBOL(ieee802154_register_device);
  
  void ieee802154_unregister_device(struct ieee802154_dev *dev)
  {
  	struct mac802154_priv *priv = mac802154_to_priv(dev);
  	struct mac802154_sub_if_data *sdata, *next;
  
  	flush_workqueue(priv->dev_workqueue);
  	destroy_workqueue(priv->dev_workqueue);
  
  	rtnl_lock();
  
  	mutex_lock(&priv->slaves_mtx);
  	priv->running = MAC802154_DEVICE_STOPPED;
  	mutex_unlock(&priv->slaves_mtx);
  
  	list_for_each_entry_safe(sdata, next, &priv->slaves, list) {
  		mutex_lock(&sdata->hw->slaves_mtx);
  		list_del(&sdata->list);
  		mutex_unlock(&sdata->hw->slaves_mtx);
  
  		unregister_netdevice(sdata->dev);
  	}
  
  	rtnl_unlock();
  
  	wpan_phy_unregister(priv->phy);
  }
  EXPORT_SYMBOL(ieee802154_unregister_device);
  
  MODULE_DESCRIPTION("IEEE 802.15.4 implementation");
  MODULE_LICENSE("GPL v2");