/*
   * Sample driver for HardMAC IEEE 802.15.4 devices
   *
   * Copyright (C) 2009 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:
   * Dmitry Eremin-Solenikov <dmitry.baryshkov@siemens.com>
   */
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/netdevice.h>
  #include <linux/skbuff.h>
  #include <linux/if_arp.h>
  
  #include <net/af_ieee802154.h>
  #include <net/ieee802154_netdev.h>
  #include <net/ieee802154.h>
  #include <net/nl802154.h>
  #include <net/wpan-phy.h>
  
  struct fakehard_priv {
  	struct wpan_phy *phy;
  };
  
  static struct wpan_phy *fake_to_phy(const struct net_device *dev)
  {
  	struct fakehard_priv *priv = netdev_priv(dev);
  	return priv->phy;
  }
  
  /**
   * fake_get_phy - Return a phy corresponding to this device.
   * @dev: The network device for which to return the wan-phy object
   *
   * This function returns a wpan-phy object corresponding to the passed
   * network device. Reference counter for wpan-phy object is incremented,
   * so when the wpan-phy isn't necessary, you should drop the reference
   * via @wpan_phy_put() call.
   */
  static struct wpan_phy *fake_get_phy(const struct net_device *dev)
  {
  	struct wpan_phy *phy = fake_to_phy(dev);
  	return to_phy(get_device(&phy->dev));
  }
  
  /**
   * fake_get_pan_id - Retrieve the PAN ID of the device.
   * @dev: The network device to retrieve the PAN of.
   *
   * Return the ID of the PAN from the PIB.
   */
  static u16 fake_get_pan_id(const struct net_device *dev)
  {
  	BUG_ON(dev->type != ARPHRD_IEEE802154);
  
  	return 0xeba1;
  }
  
  /**
   * fake_get_short_addr - Retrieve the short address of the device.
   * @dev: The network device to retrieve the short address of.
   *
   * Returns the IEEE 802.15.4 short-form address cached for this
   * device. If the device has not yet had a short address assigned
   * then this should return 0xFFFF to indicate a lack of association.
   */
  static u16 fake_get_short_addr(const struct net_device *dev)
  {
  	BUG_ON(dev->type != ARPHRD_IEEE802154);
  
  	return 0x1;
  }
  
  /**
   * fake_get_dsn - Retrieve the DSN of the device.
   * @dev: The network device to retrieve the DSN for.
   *
   * Returns the IEEE 802.15.4 DSN for the network device.
   * The DSN is the sequence number which will be added to each
   * packet or MAC command frame by the MAC during transmission.
   *
   * DSN means 'Data Sequence Number'.
   *
   * Note: This is in section 7.2.1.2 of the IEEE 802.15.4-2006
   *       document.
   */
  static u8 fake_get_dsn(const struct net_device *dev)
  {
  	BUG_ON(dev->type != ARPHRD_IEEE802154);
  
  	return 0x00; /* DSN are implemented in HW, so return just 0 */
  }
  
  /**
   * fake_assoc_req - Make an association request to the HW.
   * @dev: The network device which we are associating to a network.
   * @addr: The coordinator with which we wish to associate.
   * @channel: The channel on which to associate.
   * @cap: The capability information field to use in the association.
   *
   * Start an association with a coordinator. The coordinator's address
   * and PAN ID can be found in @addr.
   *
   * Note: This is in section 7.3.1 and 7.5.3.1 of the IEEE
   *       802.15.4-2006 document.
   */
  static int fake_assoc_req(struct net_device *dev,
  		struct ieee802154_addr *addr, u8 channel, u8 page, u8 cap)
  {
  	struct wpan_phy *phy = fake_to_phy(dev);
  
  	mutex_lock(&phy->pib_lock);
  	phy->current_channel = channel;
  	phy->current_page = page;
  	mutex_unlock(&phy->pib_lock);
  
  	/* We simply emulate it here */
  	return ieee802154_nl_assoc_confirm(dev, fake_get_short_addr(dev),
  			IEEE802154_SUCCESS);
  }
  
  /**
   * fake_assoc_resp - Send an association response to a device.
   * @dev: The network device on which to send the response.
   * @addr: The address of the device to respond to.
   * @short_addr: The assigned short address for the device (if any).
   * @status: The result of the association request.
   *
   * Queue the association response of the coordinator to another
   * device's attempt to associate with the network which we
   * coordinate. This is then added to the indirect-send queue to be
   * transmitted to the end device when it polls for data.
   *
   * Note: This is in section 7.3.2 and 7.5.3.1 of the IEEE
   *       802.15.4-2006 document.
   */
  static int fake_assoc_resp(struct net_device *dev,
  		struct ieee802154_addr *addr, u16 short_addr, u8 status)
  {
  	return 0;
  }
  
  /**
   * fake_disassoc_req - Disassociate a device from a network.
   * @dev: The network device on which we're disassociating a device.
   * @addr: The device to disassociate from the network.
   * @reason: The reason to give to the device for being disassociated.
   *
   * This sends a disassociation notification to the device being
   * disassociated from the network.
   *
   * Note: This is in section 7.5.3.2 of the IEEE 802.15.4-2006
   *       document, with the reason described in 7.3.3.2.
   */
  static int fake_disassoc_req(struct net_device *dev,
  		struct ieee802154_addr *addr, u8 reason)
  {
  	return ieee802154_nl_disassoc_confirm(dev, IEEE802154_SUCCESS);
  }
  
  /**
   * fake_start_req - Start an IEEE 802.15.4 PAN.
   * @dev: The network device on which to start the PAN.
   * @addr: The coordinator address to use when starting the PAN.
   * @channel: The channel on which to start the PAN.
   * @bcn_ord: Beacon order.
   * @sf_ord: Superframe order.
   * @pan_coord: Whether or not we are the PAN coordinator or just
   *             requesting a realignment perhaps?
   * @blx: Battery Life Extension feature bitfield.
   * @coord_realign: Something to realign something else.
   *
   * If pan_coord is non-zero then this starts a network with the
   * provided parameters, otherwise it attempts a coordinator
   * realignment of the stated network instead.
   *
   * Note: This is in section 7.5.2.3 of the IEEE 802.15.4-2006
   * document, with 7.3.8 describing coordinator realignment.
   */
  static int fake_start_req(struct net_device *dev, struct ieee802154_addr *addr,
  				u8 channel, u8 page,
  				u8 bcn_ord, u8 sf_ord, u8 pan_coord, u8 blx,
  				u8 coord_realign)
  {
  	struct wpan_phy *phy = fake_to_phy(dev);
  
  	mutex_lock(&phy->pib_lock);
  	phy->current_channel = channel;
  	phy->current_page = page;
  	mutex_unlock(&phy->pib_lock);
  
  	/* We don't emulate beacons here at all, so START should fail */
  	ieee802154_nl_start_confirm(dev, IEEE802154_INVALID_PARAMETER);
  	return 0;
  }
  
  /**
   * fake_scan_req - Start a channel scan.
   * @dev: The network device on which to perform a channel scan.
   * @type: The type of scan to perform.
   * @channels: The channel bitmask to scan.
   * @duration: How long to spend on each channel.
   *
   * This starts either a passive (energy) scan or an active (PAN) scan
   * on the channels indicated in the @channels bitmask. The duration of
   * the scan is measured in terms of superframe duration. Specifically,
   * the scan will spend aBaseSuperFrameDuration * ((2^n) + 1) on each
   * channel.
   *
   * Note: This is in section 7.5.2.1 of the IEEE 802.15.4-2006 document.
   */
  static int fake_scan_req(struct net_device *dev, u8 type, u32 channels,
  		u8 page, u8 duration)
  {
  	u8 edl[27] = {};
  	return ieee802154_nl_scan_confirm(dev, IEEE802154_SUCCESS, type,
  			channels, page,
  			type == IEEE802154_MAC_SCAN_ED ? edl : NULL);
  }
  
  static struct ieee802154_mlme_ops fake_mlme = {
  	.assoc_req = fake_assoc_req,
  	.assoc_resp = fake_assoc_resp,
  	.disassoc_req = fake_disassoc_req,
  	.start_req = fake_start_req,
  	.scan_req = fake_scan_req,
  
  	.get_phy = fake_get_phy,
  
  	.get_pan_id = fake_get_pan_id,
  	.get_short_addr = fake_get_short_addr,
  	.get_dsn = fake_get_dsn,
  };
  
  static int ieee802154_fake_open(struct net_device *dev)
  {
  	netif_start_queue(dev);
  	return 0;
  }
  
  static int ieee802154_fake_close(struct net_device *dev)
  {
  	netif_stop_queue(dev);
  	return 0;
  }
  
  static netdev_tx_t ieee802154_fake_xmit(struct sk_buff *skb,
  					      struct net_device *dev)
  {
  	dev->stats.tx_packets++;
  	dev->stats.tx_bytes += skb->len;
  
  	/* FIXME: do hardware work here ... */
  
  	dev_kfree_skb(skb);
  	return NETDEV_TX_OK;
  }
  
  
  static int ieee802154_fake_ioctl(struct net_device *dev, struct ifreq *ifr,
  		int cmd)
  {
  	struct sockaddr_ieee802154 *sa =
  		(struct sockaddr_ieee802154 *)&ifr->ifr_addr;
  	u16 pan_id, short_addr;
  
  	switch (cmd) {
  	case SIOCGIFADDR:
  		/* FIXME: fixed here, get from device IRL */
  		pan_id = fake_get_pan_id(dev);
  		short_addr = fake_get_short_addr(dev);
  		if (pan_id == IEEE802154_PANID_BROADCAST ||
  		    short_addr == IEEE802154_ADDR_BROADCAST)
  			return -EADDRNOTAVAIL;
  
  		sa->family = AF_IEEE802154;
  		sa->addr.addr_type = IEEE802154_ADDR_SHORT;
  		sa->addr.pan_id = pan_id;
  		sa->addr.short_addr = short_addr;
  		return 0;
  	}
  	return -ENOIOCTLCMD;
  }
  
  static int ieee802154_fake_mac_addr(struct net_device *dev, void *p)
  {
  	return -EBUSY; /* HW address is built into the device */
  }
  
  static const struct net_device_ops fake_ops = {
  	.ndo_open		= ieee802154_fake_open,
  	.ndo_stop		= ieee802154_fake_close,
  	.ndo_start_xmit		= ieee802154_fake_xmit,
  	.ndo_do_ioctl		= ieee802154_fake_ioctl,
  	.ndo_set_mac_address	= ieee802154_fake_mac_addr,
  };
  
  static void ieee802154_fake_destruct(struct net_device *dev)
  {
  	struct wpan_phy *phy = fake_to_phy(dev);
  
  	wpan_phy_unregister(phy);
  	free_netdev(dev);
  	wpan_phy_free(phy);
  }
  
  static void ieee802154_fake_setup(struct net_device *dev)
  {
  	dev->addr_len		= IEEE802154_ADDR_LEN;
  	memset(dev->broadcast, 0xff, IEEE802154_ADDR_LEN);
  	dev->features		= NETIF_F_HW_CSUM;
  	dev->needed_tailroom	= 2; /* FCS */
  	dev->mtu		= 127;
  	dev->tx_queue_len	= 10;
  	dev->type		= ARPHRD_IEEE802154;
  	dev->flags		= IFF_NOARP | IFF_BROADCAST;
  	dev->watchdog_timeo	= 0;
  	dev->destructor		= ieee802154_fake_destruct;
  }
  
  
  static int ieee802154fake_probe(struct platform_device *pdev)
  {
  	struct net_device *dev;
  	struct fakehard_priv *priv;
  	struct wpan_phy *phy = wpan_phy_alloc(0);
  	int err;
  
  	if (!phy)
  		return -ENOMEM;
  
  	dev = alloc_netdev(sizeof(struct fakehard_priv), "hardwpan%d", ieee802154_fake_setup);
  	if (!dev) {
  		wpan_phy_free(phy);
  		return -ENOMEM;
  	}
  
  	memcpy(dev->dev_addr, "\xba\xbe\xca\xfe\xde\xad\xbe\xef",
  			dev->addr_len);
  
  	/*
  	 * For now we'd like to emulate 2.4 GHz-only device,
  	 * both O-QPSK and CSS
  	 */
  	/* 2.4 GHz O-QPSK 802.15.4-2003 */
  	phy->channels_supported[0] |= 0x7FFF800;
  	/* 2.4 GHz CSS 802.15.4a-2007 */
  	phy->channels_supported[3] |= 0x3fff;
  
  	phy->transmit_power = 0xbf;
  
  	dev->netdev_ops = &fake_ops;
  	dev->ml_priv = &fake_mlme;
  
  	priv = netdev_priv(dev);
  	priv->phy = phy;
  
  	wpan_phy_set_dev(phy, &pdev->dev);
  	SET_NETDEV_DEV(dev, &phy->dev);
  
  	platform_set_drvdata(pdev, dev);
  
  	err = wpan_phy_register(phy);
  	if (err)
  		goto err_phy_reg;
  
  	err = register_netdev(dev);
  	if (err)
  		goto err_netdev_reg;
  
  	dev_info(&pdev->dev, "Added ieee802154 HardMAC hardware
  ");
  	return 0;
  
  err_netdev_reg:
  	wpan_phy_unregister(phy);
  err_phy_reg:
  	free_netdev(dev);
  	wpan_phy_free(phy);
  	return err;
  }
  
  static int ieee802154fake_remove(struct platform_device *pdev)
  {
  	struct net_device *dev = platform_get_drvdata(pdev);
  	unregister_netdev(dev);
  	return 0;
  }
  
  static struct platform_device *ieee802154fake_dev;
  
  static struct platform_driver ieee802154fake_driver = {
  	.probe = ieee802154fake_probe,
  	.remove = ieee802154fake_remove,
  	.driver = {
  			.name = "ieee802154hardmac",
  			.owner = THIS_MODULE,
  	},
  };
  
  static __init int fake_init(void)
  {
  	ieee802154fake_dev = platform_device_register_simple(
  			"ieee802154hardmac", -1, NULL, 0);
  	return platform_driver_register(&ieee802154fake_driver);
  }
  
  static __exit void fake_exit(void)
  {
  	platform_driver_unregister(&ieee802154fake_driver);
  	platform_device_unregister(ieee802154fake_dev);
  }
  
  module_init(fake_init);
  module_exit(fake_exit);
  MODULE_LICENSE("GPL");