/*
 * 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_get_bsn - Retrieve the BSN of the device.
 * @dev: The network device to retrieve the BSN for.
 *
 * Returns the IEEE 802.15.4 BSN for the network device.
 * The BSN is the sequence number which will be added to each
 * beacon frame sent by the MAC.
 *
 * BSN means 'Beacon Sequence Number'.
 *
 * Note: This is in section 7.2.1.2 of the IEEE 802.15.4-2006
 *       document.
 */
static u8 fake_get_bsn(const struct net_device *dev)
{
        BUG_ON(dev->type != ARPHRD_IEEE802154);

        return 0x00; /* BSN 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,
        .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 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_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;
        dev->destructor         = ieee802154_fake_destruct;
}


static int __devinit 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;
        }

        phy->dev.platform_data = dev;

        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);

        /*
         * 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;

        /*
         * 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;
        }

        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 out;

        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);
        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");