/*
   * 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.
   *
   * 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/device.h>
  #include <linux/spinlock.h>
  #include <net/mac802154.h>
  #include <net/cfg802154.h>
  
  static int numlbs = 2;
  
  static LIST_HEAD(fakelb_phys);
  static DEFINE_SPINLOCK(fakelb_phys_lock);
  
  static LIST_HEAD(fakelb_ifup_phys);
  static DEFINE_RWLOCK(fakelb_ifup_phys_lock);
  
  struct fakelb_phy {
  	struct ieee802154_hw *hw;
  
  	u8 page;
  	u8 channel;
  
  	bool suspended;
  
  	struct list_head list;
  	struct list_head list_ifup;
  };
  
  static int fakelb_hw_ed(struct ieee802154_hw *hw, u8 *level)
  {
  	BUG_ON(!level);
  	*level = 0xbe;
  
  	return 0;
  }
  
  static int fakelb_hw_channel(struct ieee802154_hw *hw, u8 page, u8 channel)
  {
  	struct fakelb_phy *phy = hw->priv;
  
  	write_lock_bh(&fakelb_ifup_phys_lock);
  	phy->page = page;
  	phy->channel = channel;
  	write_unlock_bh(&fakelb_ifup_phys_lock);
  	return 0;
  }
  
  static int fakelb_hw_xmit(struct ieee802154_hw *hw, struct sk_buff *skb)
  {
  	struct fakelb_phy *current_phy = hw->priv, *phy;
  
  	read_lock_bh(&fakelb_ifup_phys_lock);
  	WARN_ON(current_phy->suspended);
  	list_for_each_entry(phy, &fakelb_ifup_phys, list_ifup) {
  		if (current_phy == phy)
  			continue;
  
  		if (current_phy->page == phy->page &&
  		    current_phy->channel == phy->channel) {
  			struct sk_buff *newskb = pskb_copy(skb, GFP_ATOMIC);
  
  			if (newskb)
  				ieee802154_rx_irqsafe(phy->hw, newskb, 0xcc);
  		}
  	}
  	read_unlock_bh(&fakelb_ifup_phys_lock);
  
  	ieee802154_xmit_complete(hw, skb, false);
  	return 0;
  }
  
  static int fakelb_hw_start(struct ieee802154_hw *hw)
  {
  	struct fakelb_phy *phy = hw->priv;
  
  	write_lock_bh(&fakelb_ifup_phys_lock);
  	phy->suspended = false;
  	list_add(&phy->list_ifup, &fakelb_ifup_phys);
  	write_unlock_bh(&fakelb_ifup_phys_lock);
  
  	return 0;
  }
  
  static void fakelb_hw_stop(struct ieee802154_hw *hw)
  {
  	struct fakelb_phy *phy = hw->priv;
  
  	write_lock_bh(&fakelb_ifup_phys_lock);
  	phy->suspended = true;
  	list_del(&phy->list_ifup);
  	write_unlock_bh(&fakelb_ifup_phys_lock);
  }
  
  static const struct ieee802154_ops fakelb_ops = {
  	.owner = THIS_MODULE,
  	.xmit_async = 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 ieee802154_hw *hw;
  	struct fakelb_phy *phy;
  	int err;
  
  	hw = ieee802154_alloc_hw(sizeof(*phy), &fakelb_ops);
  	if (!hw)
  		return -ENOMEM;
  
  	phy = hw->priv;
  	phy->hw = hw;
  
  	/* 868 MHz BPSK	802.15.4-2003 */
  	hw->phy->supported.channels[0] |= 1;
  	/* 915 MHz BPSK	802.15.4-2003 */
  	hw->phy->supported.channels[0] |= 0x7fe;
  	/* 2.4 GHz O-QPSK 802.15.4-2003 */
  	hw->phy->supported.channels[0] |= 0x7FFF800;
  	/* 868 MHz ASK 802.15.4-2006 */
  	hw->phy->supported.channels[1] |= 1;
  	/* 915 MHz ASK 802.15.4-2006 */
  	hw->phy->supported.channels[1] |= 0x7fe;
  	/* 868 MHz O-QPSK 802.15.4-2006 */
  	hw->phy->supported.channels[2] |= 1;
  	/* 915 MHz O-QPSK 802.15.4-2006 */
  	hw->phy->supported.channels[2] |= 0x7fe;
  	/* 2.4 GHz CSS 802.15.4a-2007 */
  	hw->phy->supported.channels[3] |= 0x3fff;
  	/* UWB Sub-gigahertz 802.15.4a-2007 */
  	hw->phy->supported.channels[4] |= 1;
  	/* UWB Low band 802.15.4a-2007 */
  	hw->phy->supported.channels[4] |= 0x1e;
  	/* UWB High band 802.15.4a-2007 */
  	hw->phy->supported.channels[4] |= 0xffe0;
  	/* 750 MHz O-QPSK 802.15.4c-2009 */
  	hw->phy->supported.channels[5] |= 0xf;
  	/* 750 MHz MPSK 802.15.4c-2009 */
  	hw->phy->supported.channels[5] |= 0xf0;
  	/* 950 MHz BPSK 802.15.4d-2009 */
  	hw->phy->supported.channels[6] |= 0x3ff;
  	/* 950 MHz GFSK 802.15.4d-2009 */
  	hw->phy->supported.channels[6] |= 0x3ffc00;
  
  	ieee802154_random_extended_addr(&hw->phy->perm_extended_addr);
  	/* fake phy channel 13 as default */
  	hw->phy->current_channel = 13;
  	phy->channel = hw->phy->current_channel;
  
  	hw->parent = dev;
  
  	err = ieee802154_register_hw(hw);
  	if (err)
  		goto err_reg;
  
  	spin_lock(&fakelb_phys_lock);
  	list_add_tail(&phy->list, &fakelb_phys);
  	spin_unlock(&fakelb_phys_lock);
  
  	return 0;
  
  err_reg:
  	ieee802154_free_hw(phy->hw);
  	return err;
  }
  
  static void fakelb_del(struct fakelb_phy *phy)
  {
  	list_del(&phy->list);
  
  	ieee802154_unregister_hw(phy->hw);
  	ieee802154_free_hw(phy->hw);
  }
  
  static int fakelb_probe(struct platform_device *pdev)
  {
  	struct fakelb_phy *phy, *tmp;
  	int err, i;
  
  	for (i = 0; i < numlbs; i++) {
  		err = fakelb_add_one(&pdev->dev);
  		if (err < 0)
  			goto err_slave;
  	}
  
  	dev_info(&pdev->dev, "added ieee802154 hardware
  ");
  	return 0;
  
  err_slave:
  	spin_lock(&fakelb_phys_lock);
  	list_for_each_entry_safe(phy, tmp, &fakelb_phys, list)
  		fakelb_del(phy);
  	spin_unlock(&fakelb_phys_lock);
  	return err;
  }
  
  static int fakelb_remove(struct platform_device *pdev)
  {
  	struct fakelb_phy *phy, *tmp;
  
  	spin_lock(&fakelb_phys_lock);
  	list_for_each_entry_safe(phy, tmp, &fakelb_phys, list)
  		fakelb_del(phy);
  	spin_unlock(&fakelb_phys_lock);
  	return 0;
  }
  
  static struct platform_device *ieee802154fake_dev;
  
  static struct platform_driver ieee802154fake_driver = {
  	.probe = fakelb_probe,
  	.remove = fakelb_remove,
  	.driver = {
  			.name = "ieee802154fakelb",
  	},
  };
  
  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");