/*
 * 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/ieee802154/af_ieee802154.h>
#include <net/ieee802154/netdevice.h>
#include <net/ieee802154/mac_def.h>
#include <net/ieee802154/nl802154.h>

static u16 fake_get_pan_id(struct net_device *dev)
{
	BUG_ON(dev->type != ARPHRD_IEEE802154);

	return 0xeba1;
}

static u16 fake_get_short_addr(struct net_device *dev)
{
	BUG_ON(dev->type != ARPHRD_IEEE802154);

	return 0x1;
}

static u8 fake_get_dsn(struct net_device *dev)
{
	BUG_ON(dev->type != ARPHRD_IEEE802154);

	return 0x00; /* DSN are implemented in HW, so return just 0 */
}

static u8 fake_get_bsn(struct net_device *dev)
{
	BUG_ON(dev->type != ARPHRD_IEEE802154);

	return 0x00; /* BSN are implemented in HW, so return just 0 */
}

static int fake_assoc_req(struct net_device *dev,
		struct ieee802154_addr *addr, u8 channel, u8 cap)
{
	/* We simply emulate it here */
	return ieee802154_nl_assoc_confirm(dev, fake_get_short_addr(dev),
			IEEE802154_SUCCESS);
}

static int fake_assoc_resp(struct net_device *dev,
		struct ieee802154_addr *addr, u16 short_addr, u8 status)
{
	return 0;
}

static int fake_disassoc_req(struct net_device *dev,
		struct ieee802154_addr *addr, u8 reason)
{
	return ieee802154_nl_disassoc_confirm(dev, IEEE802154_SUCCESS);
}

static int fake_start_req(struct net_device *dev, struct ieee802154_addr *addr,
				u8 channel,
				u8 bcn_ord, u8 sf_ord, u8 pan_coord, u8 blx,
				u8 coord_realign)
{
	return 0;
}

static int fake_scan_req(struct net_device *dev, u8 type, u32 channels,
		u8 duration)
{
	u8 edl[27] = {};
	return ieee802154_nl_scan_confirm(dev, IEEE802154_SUCCESS, type,
			channels,
			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_pan_id = fake_get_pan_id,
	.get_short_addr = fake_get_short_addr,
	.get_dsn = fake_get_dsn,
	.get_bsn = fake_get_bsn,
};

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 int ieee802154_fake_xmit(struct sk_buff *skb, struct net_device *dev)
{
	skb->iif = dev->ifindex;
	skb->dev = dev;
	dev->stats.tx_packets++;
	dev->stats.tx_bytes += skb->len;

	dev->trans_start = jiffies;

	/* FIXME: do hardware work here ... */

	return 0;
}


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_setup(struct net_device *dev)
{
	dev->addr_len		= IEEE802154_ADDR_LEN;
	memset(dev->broadcast, 0xff, IEEE802154_ADDR_LEN);
	dev->features		= NETIF_F_NO_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;
}


static int __devinit ieee802154fake_probe(struct platform_device *pdev)
{
	struct net_device *dev =
		alloc_netdev(0, "hardwpan%d", ieee802154_fake_setup);
	int err;

	if (!dev)
		return -ENOMEM;

	memcpy(dev->dev_addr, "\xba\xbe\xca\xfe\xde\xad\xbe\xef",
			dev->addr_len);
	memcpy(dev->perm_addr, dev->dev_addr, dev->addr_len);

	dev->netdev_ops = &fake_ops;
	dev->ml_priv = &fake_mlme;

	/*
	 * If the name is a format string the caller wants us to do a
	 * name allocation.
	 */
	if (strchr(dev->name, '%')) {
		err = dev_alloc_name(dev, dev->name);
		if (err < 0)
			goto out;
	}

	SET_NETDEV_DEV(dev, &pdev->dev);

	platform_set_drvdata(pdev, dev);

	err = register_netdev(dev);
	if (err < 0)
		goto out;


	dev_info(&pdev->dev, "Added ieee802154 HardMAC hardware\n");
	return 0;

out:
	unregister_netdev(dev);
	return err;
}

static int __devexit ieee802154fake_remove(struct platform_device *pdev)
{
	struct net_device *dev = platform_get_drvdata(pdev);
	unregister_netdev(dev);
	free_netdev(dev);
	return 0;
}

static struct platform_device *ieee802154fake_dev;

static struct platform_driver ieee802154fake_driver = {
	.probe = ieee802154fake_probe,
	.remove = __devexit_p(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");