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zd_mac.c

/* zd_mac.c
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/wireless.h>
#include <linux/usb.h>
#include <linux/jiffies.h>
#include <net/ieee80211_radiotap.h>

#include "zd_def.h"
#include "zd_chip.h"
#include "zd_mac.h"
#include "zd_ieee80211.h"
#include "zd_netdev.h"
#include "zd_rf.h"

static void ieee_init(struct ieee80211_device *ieee);
static void softmac_init(struct ieee80211softmac_device *sm);
static void set_rts_cts_work(struct work_struct *work);
static void set_basic_rates_work(struct work_struct *work);

static void housekeeping_init(struct zd_mac *mac);
static void housekeeping_enable(struct zd_mac *mac);
static void housekeeping_disable(struct zd_mac *mac);

static void set_multicast_hash_handler(struct work_struct *work);

static void do_rx(unsigned long mac_ptr);

int zd_mac_init(struct zd_mac *mac,
              struct net_device *netdev,
              struct usb_interface *intf)
{
      struct ieee80211_device *ieee = zd_netdev_ieee80211(netdev);

      memset(mac, 0, sizeof(*mac));
      spin_lock_init(&mac->lock);
      mac->netdev = netdev;
      INIT_DELAYED_WORK(&mac->set_rts_cts_work, set_rts_cts_work);
      INIT_DELAYED_WORK(&mac->set_basic_rates_work, set_basic_rates_work);

      skb_queue_head_init(&mac->rx_queue);
      tasklet_init(&mac->rx_tasklet, do_rx, (unsigned long)mac);
      tasklet_disable(&mac->rx_tasklet);

      ieee_init(ieee);
      softmac_init(ieee80211_priv(netdev));
      zd_chip_init(&mac->chip, netdev, intf);
      housekeeping_init(mac);
      INIT_WORK(&mac->set_multicast_hash_work, set_multicast_hash_handler);
      return 0;
}

static int reset_channel(struct zd_mac *mac)
{
      int r;
      unsigned long flags;
      const struct channel_range *range;

      spin_lock_irqsave(&mac->lock, flags);
      range = zd_channel_range(mac->regdomain);
      if (!range->start) {
            r = -EINVAL;
            goto out;
      }
      mac->requested_channel = range->start;
      r = 0;
out:
      spin_unlock_irqrestore(&mac->lock, flags);
      return r;
}

int zd_mac_preinit_hw(struct zd_mac *mac)
{
      int r;
      u8 addr[ETH_ALEN];

      r = zd_chip_read_mac_addr_fw(&mac->chip, addr);
      if (r)
            return r;

      memcpy(mac->netdev->dev_addr, addr, ETH_ALEN);
      return 0;
}

int zd_mac_init_hw(struct zd_mac *mac)
{
      int r;
      struct zd_chip *chip = &mac->chip;
      u8 default_regdomain;

      r = zd_chip_enable_int(chip);
      if (r)
            goto out;
      r = zd_chip_init_hw(chip);
      if (r)
            goto disable_int;

      ZD_ASSERT(!irqs_disabled());

      r = zd_read_regdomain(chip, &default_regdomain);
      if (r)
            goto disable_int;
      if (!zd_regdomain_supported(default_regdomain)) {
            /* The vendor driver overrides the regulatory domain and
             * allowed channel registers and unconditionally restricts
             * available channels to 1-11 everywhere. Match their
             * questionable behaviour only for regdomains which we don't
             * recognise. */
            dev_warn(zd_mac_dev(mac),  "Unrecognised regulatory domain: "
                  "%#04x. Defaulting to FCC.\n", default_regdomain);
            default_regdomain = ZD_REGDOMAIN_FCC;
      }
      spin_lock_irq(&mac->lock);
      mac->regdomain = mac->default_regdomain = default_regdomain;
      spin_unlock_irq(&mac->lock);
      r = reset_channel(mac);
      if (r)
            goto disable_int;

      /* We must inform the device that we are doing encryption/decryption in
       * software at the moment. */
      r = zd_set_encryption_type(chip, ENC_SNIFFER);
      if (r)
            goto disable_int;

      r = zd_geo_init(zd_mac_to_ieee80211(mac), mac->regdomain);
      if (r)
            goto disable_int;

      r = 0;
disable_int:
      zd_chip_disable_int(chip);
out:
      return r;
}

void zd_mac_clear(struct zd_mac *mac)
{
      flush_workqueue(zd_workqueue);
      skb_queue_purge(&mac->rx_queue);
      tasklet_kill(&mac->rx_tasklet);
      zd_chip_clear(&mac->chip);
      ZD_ASSERT(!spin_is_locked(&mac->lock));
      ZD_MEMCLEAR(mac, sizeof(struct zd_mac));
}

static int set_rx_filter(struct zd_mac *mac)
{
      struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);
      u32 filter = (ieee->iw_mode == IW_MODE_MONITOR) ? ~0 : STA_RX_FILTER;
      return zd_iowrite32(&mac->chip, CR_RX_FILTER, filter);
}

static int set_sniffer(struct zd_mac *mac)
{
      struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);
      return zd_iowrite32(&mac->chip, CR_SNIFFER_ON,
            ieee->iw_mode == IW_MODE_MONITOR ? 1 : 0);
      return 0;
}

static int set_mc_hash(struct zd_mac *mac)
{
      struct zd_mc_hash hash;
      struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);

      zd_mc_clear(&hash);
      if (ieee->iw_mode == IW_MODE_MONITOR)
            zd_mc_add_all(&hash);

      return zd_chip_set_multicast_hash(&mac->chip, &hash);
}

int zd_mac_open(struct net_device *netdev)
{
      struct zd_mac *mac = zd_netdev_mac(netdev);
      struct zd_chip *chip = &mac->chip;
      struct zd_usb *usb = &chip->usb;
      int r;

      if (!usb->initialized) {
            r = zd_usb_init_hw(usb);
            if (r)
                  goto out;
      }

      tasklet_enable(&mac->rx_tasklet);

      r = zd_chip_enable_int(chip);
      if (r < 0)
            goto out;

      r = zd_write_mac_addr(chip, netdev->dev_addr);
      if (r)
            goto disable_int;

      r = zd_chip_set_basic_rates(chip, CR_RATES_80211B | CR_RATES_80211G);
      if (r < 0)
            goto disable_int;
      r = set_rx_filter(mac);
      if (r)
            goto disable_int;
      r = set_sniffer(mac);
      if (r)
            goto disable_int;
      r = set_mc_hash(mac);
      if (r)
            goto disable_int;
      r = zd_chip_switch_radio_on(chip);
      if (r < 0)
            goto disable_int;
      r = zd_chip_set_channel(chip, mac->requested_channel);
      if (r < 0)
            goto disable_radio;
      r = zd_chip_enable_rx(chip);
      if (r < 0)
            goto disable_radio;
      r = zd_chip_enable_hwint(chip);
      if (r < 0)
            goto disable_rx;

      housekeeping_enable(mac);
      ieee80211softmac_start(netdev);
      return 0;
disable_rx:
      zd_chip_disable_rx(chip);
disable_radio:
      zd_chip_switch_radio_off(chip);
disable_int:
      zd_chip_disable_int(chip);
out:
      return r;
}

int zd_mac_stop(struct net_device *netdev)
{
      struct zd_mac *mac = zd_netdev_mac(netdev);
      struct zd_chip *chip = &mac->chip;

      netif_stop_queue(netdev);

      /*
       * The order here deliberately is a little different from the open()
       * method, since we need to make sure there is no opportunity for RX
       * frames to be processed by softmac after we have stopped it.
       */

      zd_chip_disable_rx(chip);
      skb_queue_purge(&mac->rx_queue);
      tasklet_disable(&mac->rx_tasklet);
      housekeeping_disable(mac);
      ieee80211softmac_stop(netdev);

      /* Ensure no work items are running or queued from this point */
      cancel_delayed_work(&mac->set_rts_cts_work);
      cancel_delayed_work(&mac->set_basic_rates_work);
      flush_workqueue(zd_workqueue);
      mac->updating_rts_rate = 0;
      mac->updating_basic_rates = 0;

      zd_chip_disable_hwint(chip);
      zd_chip_switch_radio_off(chip);
      zd_chip_disable_int(chip);

      return 0;
}

int zd_mac_set_mac_address(struct net_device *netdev, void *p)
{
      int r;
      unsigned long flags;
      struct sockaddr *addr = p;
      struct zd_mac *mac = zd_netdev_mac(netdev);
      struct zd_chip *chip = &mac->chip;
      DECLARE_MAC_BUF(mac2);

      if (!is_valid_ether_addr(addr->sa_data))
            return -EADDRNOTAVAIL;

      dev_dbg_f(zd_mac_dev(mac),
              "Setting MAC to %s\n", print_mac(mac2, addr->sa_data));

      if (netdev->flags & IFF_UP) {
            r = zd_write_mac_addr(chip, addr->sa_data);
            if (r)
                  return r;
      }

      spin_lock_irqsave(&mac->lock, flags);
      memcpy(netdev->dev_addr, addr->sa_data, ETH_ALEN);
      spin_unlock_irqrestore(&mac->lock, flags);

      return 0;
}

static void set_multicast_hash_handler(struct work_struct *work)
{
      struct zd_mac *mac = container_of(work, struct zd_mac,
                                set_multicast_hash_work);
      struct zd_mc_hash hash;

      spin_lock_irq(&mac->lock);
      hash = mac->multicast_hash;
      spin_unlock_irq(&mac->lock);

      zd_chip_set_multicast_hash(&mac->chip, &hash);
}

void zd_mac_set_multicast_list(struct net_device *dev)
{
      struct zd_mac *mac = zd_netdev_mac(dev);
      struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);
      struct zd_mc_hash hash;
      struct dev_mc_list *mc;
      unsigned long flags;
      DECLARE_MAC_BUF(mac2);

      if (dev->flags & (IFF_PROMISC|IFF_ALLMULTI) ||
                  ieee->iw_mode == IW_MODE_MONITOR) {
            zd_mc_add_all(&hash);
      } else {
            zd_mc_clear(&hash);
            for (mc = dev->mc_list; mc; mc = mc->next) {
                  dev_dbg_f(zd_mac_dev(mac), "mc addr %s\n",
                          print_mac(mac2, mc->dmi_addr));
                  zd_mc_add_addr(&hash, mc->dmi_addr);
            }
      }

      spin_lock_irqsave(&mac->lock, flags);
      mac->multicast_hash = hash;
      spin_unlock_irqrestore(&mac->lock, flags);
      queue_work(zd_workqueue, &mac->set_multicast_hash_work);
}

int zd_mac_set_regdomain(struct zd_mac *mac, u8 regdomain)
{
      int r;
      u8 channel;

      ZD_ASSERT(!irqs_disabled());
      spin_lock_irq(&mac->lock);
      if (regdomain == 0) {
            regdomain = mac->default_regdomain;
      }
      if (!zd_regdomain_supported(regdomain)) {
            spin_unlock_irq(&mac->lock);
            return -EINVAL;
      }
      mac->regdomain = regdomain;
      channel = mac->requested_channel;
      spin_unlock_irq(&mac->lock);

      r = zd_geo_init(zd_mac_to_ieee80211(mac), regdomain);
      if (r)
            return r;
      if (!zd_regdomain_supports_channel(regdomain, channel)) {
            r = reset_channel(mac);
            if (r)
                  return r;
      }

      return 0;
}

u8 zd_mac_get_regdomain(struct zd_mac *mac)
{
      unsigned long flags;
      u8 regdomain;

      spin_lock_irqsave(&mac->lock, flags);
      regdomain = mac->regdomain;
      spin_unlock_irqrestore(&mac->lock, flags);
      return regdomain;
}

/* Fallback to lowest rate, if rate is unknown. */
static u8 rate_to_zd_rate(u8 rate)
{
      switch (rate) {
      case IEEE80211_CCK_RATE_2MB:
            return ZD_CCK_RATE_2M;
      case IEEE80211_CCK_RATE_5MB:
            return ZD_CCK_RATE_5_5M;
      case IEEE80211_CCK_RATE_11MB:
            return ZD_CCK_RATE_11M;
      case IEEE80211_OFDM_RATE_6MB:
            return ZD_OFDM_RATE_6M;
      case IEEE80211_OFDM_RATE_9MB:
            return ZD_OFDM_RATE_9M;
      case IEEE80211_OFDM_RATE_12MB:
            return ZD_OFDM_RATE_12M;
      case IEEE80211_OFDM_RATE_18MB:
            return ZD_OFDM_RATE_18M;
      case IEEE80211_OFDM_RATE_24MB:
            return ZD_OFDM_RATE_24M;
      case IEEE80211_OFDM_RATE_36MB:
            return ZD_OFDM_RATE_36M;
      case IEEE80211_OFDM_RATE_48MB:
            return ZD_OFDM_RATE_48M;
      case IEEE80211_OFDM_RATE_54MB:
            return ZD_OFDM_RATE_54M;
      }
      return ZD_CCK_RATE_1M;
}

static u16 rate_to_cr_rate(u8 rate)
{
      switch (rate) {
      case IEEE80211_CCK_RATE_2MB:
            return CR_RATE_1M;
      case IEEE80211_CCK_RATE_5MB:
            return CR_RATE_5_5M;
      case IEEE80211_CCK_RATE_11MB:
            return CR_RATE_11M;
      case IEEE80211_OFDM_RATE_6MB:
            return CR_RATE_6M;
      case IEEE80211_OFDM_RATE_9MB:
            return CR_RATE_9M;
      case IEEE80211_OFDM_RATE_12MB:
            return CR_RATE_12M;
      case IEEE80211_OFDM_RATE_18MB:
            return CR_RATE_18M;
      case IEEE80211_OFDM_RATE_24MB:
            return CR_RATE_24M;
      case IEEE80211_OFDM_RATE_36MB:
            return CR_RATE_36M;
      case IEEE80211_OFDM_RATE_48MB:
            return CR_RATE_48M;
      case IEEE80211_OFDM_RATE_54MB:
            return CR_RATE_54M;
      }
      return CR_RATE_1M;
}

static void try_enable_tx(struct zd_mac *mac)
{
      unsigned long flags;

      spin_lock_irqsave(&mac->lock, flags);
      if (mac->updating_rts_rate == 0 && mac->updating_basic_rates == 0)
            netif_wake_queue(mac->netdev);
      spin_unlock_irqrestore(&mac->lock, flags);
}

static void set_rts_cts_work(struct work_struct *work)
{
      struct zd_mac *mac =
            container_of(work, struct zd_mac, set_rts_cts_work.work);
      unsigned long flags;
      u8 rts_rate;
      unsigned int short_preamble;

      mutex_lock(&mac->chip.mutex);

      spin_lock_irqsave(&mac->lock, flags);
      mac->updating_rts_rate = 0;
      rts_rate = mac->rts_rate;
      short_preamble = mac->short_preamble;
      spin_unlock_irqrestore(&mac->lock, flags);

      zd_chip_set_rts_cts_rate_locked(&mac->chip, rts_rate, short_preamble);
      mutex_unlock(&mac->chip.mutex);

      try_enable_tx(mac);
}

static void set_basic_rates_work(struct work_struct *work)
{
      struct zd_mac *mac =
            container_of(work, struct zd_mac, set_basic_rates_work.work);
      unsigned long flags;
      u16 basic_rates;

      mutex_lock(&mac->chip.mutex);

      spin_lock_irqsave(&mac->lock, flags);
      mac->updating_basic_rates = 0;
      basic_rates = mac->basic_rates;
      spin_unlock_irqrestore(&mac->lock, flags);

      zd_chip_set_basic_rates_locked(&mac->chip, basic_rates);
      mutex_unlock(&mac->chip.mutex);

      try_enable_tx(mac);
}

static void bssinfo_change(struct net_device *netdev, u32 changes)
{
      struct zd_mac *mac = zd_netdev_mac(netdev);
      struct ieee80211softmac_device *softmac = ieee80211_priv(netdev);
      struct ieee80211softmac_bss_info *bssinfo = &softmac->bssinfo;
      int need_set_rts_cts = 0;
      int need_set_rates = 0;
      u16 basic_rates;
      unsigned long flags;

      dev_dbg_f(zd_mac_dev(mac), "changes: %x\n", changes);

      if (changes & IEEE80211SOFTMAC_BSSINFOCHG_SHORT_PREAMBLE) {
            spin_lock_irqsave(&mac->lock, flags);
            mac->short_preamble = bssinfo->short_preamble;
            spin_unlock_irqrestore(&mac->lock, flags);
            need_set_rts_cts = 1;
      }

      if (changes & IEEE80211SOFTMAC_BSSINFOCHG_RATES) {
            /* Set RTS rate to highest available basic rate */
            u8 hi_rate = ieee80211softmac_highest_supported_rate(softmac,
                  &bssinfo->supported_rates, 1);
            hi_rate = rate_to_zd_rate(hi_rate);

            spin_lock_irqsave(&mac->lock, flags);
            if (hi_rate != mac->rts_rate) {
                  mac->rts_rate = hi_rate;
                  need_set_rts_cts = 1;
            }
            spin_unlock_irqrestore(&mac->lock, flags);

            /* Set basic rates */
            need_set_rates = 1;
            if (bssinfo->supported_rates.count == 0) {
                  /* Allow the device to be flexible */
                  basic_rates = CR_RATES_80211B | CR_RATES_80211G;
            } else {
                  int i = 0;
                  basic_rates = 0;

                  for (i = 0; i < bssinfo->supported_rates.count; i++) {
                        u16 rate = bssinfo->supported_rates.rates[i];
                        if ((rate & IEEE80211_BASIC_RATE_MASK) == 0)
                              continue;

                        rate &= ~IEEE80211_BASIC_RATE_MASK;
                        basic_rates |= rate_to_cr_rate(rate);
                  }
            }
            spin_lock_irqsave(&mac->lock, flags);
            mac->basic_rates = basic_rates;
            spin_unlock_irqrestore(&mac->lock, flags);
      }

      /* Schedule any changes we made above */

      spin_lock_irqsave(&mac->lock, flags);
      if (need_set_rts_cts && !mac->updating_rts_rate) {
            mac->updating_rts_rate = 1;
            netif_stop_queue(mac->netdev);
            queue_delayed_work(zd_workqueue, &mac->set_rts_cts_work, 0);
      }
      if (need_set_rates && !mac->updating_basic_rates) {
            mac->updating_basic_rates = 1;
            netif_stop_queue(mac->netdev);
            queue_delayed_work(zd_workqueue, &mac->set_basic_rates_work,
                           0);
      }
      spin_unlock_irqrestore(&mac->lock, flags);
}

static void set_channel(struct net_device *netdev, u8 channel)
{
      struct zd_mac *mac = zd_netdev_mac(netdev);

      dev_dbg_f(zd_mac_dev(mac), "channel %d\n", channel);

      zd_chip_set_channel(&mac->chip, channel);
}

int zd_mac_request_channel(struct zd_mac *mac, u8 channel)
{
      unsigned long lock_flags;
      struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);

      if (ieee->iw_mode == IW_MODE_INFRA)
            return -EPERM;

      spin_lock_irqsave(&mac->lock, lock_flags);
      if (!zd_regdomain_supports_channel(mac->regdomain, channel)) {
            spin_unlock_irqrestore(&mac->lock, lock_flags);
            return -EINVAL;
      }
      mac->requested_channel = channel;
      spin_unlock_irqrestore(&mac->lock, lock_flags);
      if (netif_running(mac->netdev))
            return zd_chip_set_channel(&mac->chip, channel);
      else
            return 0;
}

u8 zd_mac_get_channel(struct zd_mac *mac)
{
      u8 channel = zd_chip_get_channel(&mac->chip);

      dev_dbg_f(zd_mac_dev(mac), "channel %u\n", channel);
      return channel;
}

int zd_mac_set_mode(struct zd_mac *mac, u32 mode)
{
      struct ieee80211_device *ieee;

      switch (mode) {
      case IW_MODE_AUTO:
      case IW_MODE_ADHOC:
      case IW_MODE_INFRA:
            mac->netdev->type = ARPHRD_ETHER;
            break;
      case IW_MODE_MONITOR:
            mac->netdev->type = ARPHRD_IEEE80211_RADIOTAP;
            break;
      default:
            dev_dbg_f(zd_mac_dev(mac), "wrong mode %u\n", mode);
            return -EINVAL;
      }

      ieee = zd_mac_to_ieee80211(mac);
      ZD_ASSERT(!irqs_disabled());
      spin_lock_irq(&ieee->lock);
      ieee->iw_mode = mode;
      spin_unlock_irq(&ieee->lock);

      if (netif_running(mac->netdev)) {
            int r = set_rx_filter(mac);
            if (r)
                  return r;
            return set_sniffer(mac);
      }

      return 0;
}

int zd_mac_get_mode(struct zd_mac *mac, u32 *mode)
{
      unsigned long flags;
      struct ieee80211_device *ieee;

      ieee = zd_mac_to_ieee80211(mac);
      spin_lock_irqsave(&ieee->lock, flags);
      *mode = ieee->iw_mode;
      spin_unlock_irqrestore(&ieee->lock, flags);
      return 0;
}

int zd_mac_get_range(struct zd_mac *mac, struct iw_range *range)
{
      int i;
      const struct channel_range *channel_range;
      u8 regdomain;

      memset(range, 0, sizeof(*range));

      /* FIXME: Not so important and depends on the mode. For 802.11g
       * usually this value is used. It seems to be that Bit/s number is
       * given here.
       */
      range->throughput = 27 * 1000 * 1000;

      range->max_qual.qual = 100;
      range->max_qual.level = 100;

      /* FIXME: Needs still to be tuned. */
      range->avg_qual.qual = 71;
      range->avg_qual.level = 80;

      /* FIXME: depends on standard? */
      range->min_rts = 256;
      range->max_rts = 2346;

      range->min_frag = MIN_FRAG_THRESHOLD;
      range->max_frag = MAX_FRAG_THRESHOLD;

      range->max_encoding_tokens = WEP_KEYS;
      range->num_encoding_sizes = 2;
      range->encoding_size[0] = 5;
      range->encoding_size[1] = WEP_KEY_LEN;

      range->we_version_compiled = WIRELESS_EXT;
      range->we_version_source = 20;

      range->enc_capa = IW_ENC_CAPA_WPA |  IW_ENC_CAPA_WPA2 |
                    IW_ENC_CAPA_CIPHER_TKIP | IW_ENC_CAPA_CIPHER_CCMP;

      ZD_ASSERT(!irqs_disabled());
      spin_lock_irq(&mac->lock);
      regdomain = mac->regdomain;
      spin_unlock_irq(&mac->lock);
      channel_range = zd_channel_range(regdomain);

      range->num_channels = channel_range->end - channel_range->start;
      range->old_num_channels = range->num_channels;
      range->num_frequency = range->num_channels;
      range->old_num_frequency = range->num_frequency;

      for (i = 0; i < range->num_frequency; i++) {
            struct iw_freq *freq = &range->freq[i];
            freq->i = channel_range->start + i;
            zd_channel_to_freq(freq, freq->i);
      }

      return 0;
}

static int zd_calc_tx_length_us(u8 *service, u8 zd_rate, u16 tx_length)
{
      /* ZD_PURE_RATE() must be used to remove the modulation type flag of
       * the zd-rate values. */
      static const u8 rate_divisor[] = {
            [ZD_PURE_RATE(ZD_CCK_RATE_1M)]            =  1,
            [ZD_PURE_RATE(ZD_CCK_RATE_2M)]            =  2,

            /* bits must be doubled */
            [ZD_PURE_RATE(ZD_CCK_RATE_5_5M)]    = 11,

            [ZD_PURE_RATE(ZD_CCK_RATE_11M)]           = 11,
            [ZD_PURE_RATE(ZD_OFDM_RATE_6M)]           =  6,
            [ZD_PURE_RATE(ZD_OFDM_RATE_9M)]           =  9,
            [ZD_PURE_RATE(ZD_OFDM_RATE_12M)]    = 12,
            [ZD_PURE_RATE(ZD_OFDM_RATE_18M)]    = 18,
            [ZD_PURE_RATE(ZD_OFDM_RATE_24M)]    = 24,
            [ZD_PURE_RATE(ZD_OFDM_RATE_36M)]    = 36,
            [ZD_PURE_RATE(ZD_OFDM_RATE_48M)]    = 48,
            [ZD_PURE_RATE(ZD_OFDM_RATE_54M)]    = 54,
      };

      u32 bits = (u32)tx_length * 8;
      u32 divisor;

      divisor = rate_divisor[ZD_PURE_RATE(zd_rate)];
      if (divisor == 0)
            return -EINVAL;

      switch (zd_rate) {
      case ZD_CCK_RATE_5_5M:
            bits = (2*bits) + 10; /* round up to the next integer */
            break;
      case ZD_CCK_RATE_11M:
            if (service) {
                  u32 t = bits % 11;
                  *service &= ~ZD_PLCP_SERVICE_LENGTH_EXTENSION;
                  if (0 < t && t <= 3) {
                        *service |= ZD_PLCP_SERVICE_LENGTH_EXTENSION;
                  }
            }
            bits += 10; /* round up to the next integer */
            break;
      }

      return bits/divisor;
}

static void cs_set_modulation(struct zd_mac *mac, struct zd_ctrlset *cs,
                            struct ieee80211_hdr_4addr *hdr)
{
      struct ieee80211softmac_device *softmac = ieee80211_priv(mac->netdev);
      u16 ftype = WLAN_FC_GET_TYPE(le16_to_cpu(hdr->frame_ctl));
      u8 rate;
      int is_mgt = (ftype == IEEE80211_FTYPE_MGMT) != 0;
      int is_multicast = is_multicast_ether_addr(hdr->addr1);
      int short_preamble = ieee80211softmac_short_preamble_ok(softmac,
            is_multicast, is_mgt);

      rate = ieee80211softmac_suggest_txrate(softmac, is_multicast, is_mgt);
      cs->modulation = rate_to_zd_rate(rate);

      /* Set short preamble bit when appropriate */
      if (short_preamble && ZD_MODULATION_TYPE(cs->modulation) == ZD_CCK
          && cs->modulation != ZD_CCK_RATE_1M)
            cs->modulation |= ZD_CCK_PREA_SHORT;
}

static void cs_set_control(struct zd_mac *mac, struct zd_ctrlset *cs,
                         struct ieee80211_hdr_4addr *header)
{
      struct ieee80211softmac_device *softmac = ieee80211_priv(mac->netdev);
      unsigned int tx_length = le16_to_cpu(cs->tx_length);
      u16 fctl = le16_to_cpu(header->frame_ctl);
      u16 ftype = WLAN_FC_GET_TYPE(fctl);
      u16 stype = WLAN_FC_GET_STYPE(fctl);

      /*
       * CONTROL TODO:
       * - if backoff needed, enable bit 0
       * - if burst (backoff not needed) disable bit 0
       */

      cs->control = 0;

      /* First fragment */
      if (WLAN_GET_SEQ_FRAG(le16_to_cpu(header->seq_ctl)) == 0)
            cs->control |= ZD_CS_NEED_RANDOM_BACKOFF;

      /* Multicast */
      if (is_multicast_ether_addr(header->addr1))
            cs->control |= ZD_CS_MULTICAST;

      /* PS-POLL */
      if (ftype == IEEE80211_FTYPE_CTL && stype == IEEE80211_STYPE_PSPOLL)
            cs->control |= ZD_CS_PS_POLL_FRAME;

      /* Unicast data frames over the threshold should have RTS */
      if (!is_multicast_ether_addr(header->addr1) &&
            ftype != IEEE80211_FTYPE_MGMT &&
                tx_length > zd_netdev_ieee80211(mac->netdev)->rts)
            cs->control |= ZD_CS_RTS;

      /* Use CTS-to-self protection if required */
      if (ZD_MODULATION_TYPE(cs->modulation) == ZD_OFDM &&
                  ieee80211softmac_protection_needed(softmac)) {
            /* FIXME: avoid sending RTS *and* self-CTS, is that correct? */
            cs->control &= ~ZD_CS_RTS;
            cs->control |= ZD_CS_SELF_CTS;
      }

      /* FIXME: Management frame? */
}

static int fill_ctrlset(struct zd_mac *mac,
                      struct ieee80211_txb *txb,
                  int frag_num)
{
      int r;
      struct sk_buff *skb = txb->fragments[frag_num];
      struct ieee80211_hdr_4addr *hdr =
            (struct ieee80211_hdr_4addr *) skb->data;
      unsigned int frag_len = skb->len + IEEE80211_FCS_LEN;
      unsigned int next_frag_len;
      unsigned int packet_length;
      struct zd_ctrlset *cs = (struct zd_ctrlset *)
            skb_push(skb, sizeof(struct zd_ctrlset));

      if (frag_num+1  < txb->nr_frags) {
            next_frag_len = txb->fragments[frag_num+1]->len +
                          IEEE80211_FCS_LEN;
      } else {
            next_frag_len = 0;
      }
      ZD_ASSERT(frag_len <= 0xffff);
      ZD_ASSERT(next_frag_len <= 0xffff);

      cs_set_modulation(mac, cs, hdr);

      cs->tx_length = cpu_to_le16(frag_len);

      cs_set_control(mac, cs, hdr);

      packet_length = frag_len + sizeof(struct zd_ctrlset) + 10;
      ZD_ASSERT(packet_length <= 0xffff);
      /* ZD1211B: Computing the length difference this way, gives us
       * flexibility to compute the packet length.
       */
      cs->packet_length = cpu_to_le16(zd_chip_is_zd1211b(&mac->chip) ?
                  packet_length - frag_len : packet_length);

      /*
       * CURRENT LENGTH:
       * - transmit frame length in microseconds
       * - seems to be derived from frame length
       * - see Cal_Us_Service() in zdinlinef.h
       * - if macp->bTxBurstEnable is enabled, then multiply by 4
       *  - bTxBurstEnable is never set in the vendor driver
       *
       * SERVICE:
       * - "for PLCP configuration"
       * - always 0 except in some situations at 802.11b 11M
       * - see line 53 of zdinlinef.h
       */
      cs->service = 0;
      r = zd_calc_tx_length_us(&cs->service, ZD_RATE(cs->modulation),
                             le16_to_cpu(cs->tx_length));
      if (r < 0)
            return r;
      cs->current_length = cpu_to_le16(r);

      if (next_frag_len == 0) {
            cs->next_frame_length = 0;
      } else {
            r = zd_calc_tx_length_us(NULL, ZD_RATE(cs->modulation),
                                   next_frag_len);
            if (r < 0)
                  return r;
            cs->next_frame_length = cpu_to_le16(r);
      }

      return 0;
}

static int zd_mac_tx(struct zd_mac *mac, struct ieee80211_txb *txb, int pri)
{
      int i, r;
      struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);

      for (i = 0; i < txb->nr_frags; i++) {
            struct sk_buff *skb = txb->fragments[i];

            r = fill_ctrlset(mac, txb, i);
            if (r) {
                  ieee->stats.tx_dropped++;
                  return r;
            }
            r = zd_usb_tx(&mac->chip.usb, skb->data, skb->len);
            if (r) {
                  ieee->stats.tx_dropped++;
                  return r;
            }
      }

      /* FIXME: shouldn't this be handled by the upper layers? */
      mac->netdev->trans_start = jiffies;

      ieee80211_txb_free(txb);
      return 0;
}

struct zd_rt_hdr {
      struct ieee80211_radiotap_header rt_hdr;
      u8  rt_flags;
      u8  rt_rate;
      u16 rt_channel;
      u16 rt_chbitmask;
} __attribute__((packed));

static void fill_rt_header(void *buffer, struct zd_mac *mac,
                         const struct ieee80211_rx_stats *stats,
                     const struct rx_status *status)
{
      struct zd_rt_hdr *hdr = buffer;

      hdr->rt_hdr.it_version = PKTHDR_RADIOTAP_VERSION;
      hdr->rt_hdr.it_pad = 0;
      hdr->rt_hdr.it_len = cpu_to_le16(sizeof(struct zd_rt_hdr));
      hdr->rt_hdr.it_present = cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
                             (1 << IEEE80211_RADIOTAP_CHANNEL) |
                         (1 << IEEE80211_RADIOTAP_RATE));

      hdr->rt_flags = 0;
      if (status->decryption_type & (ZD_RX_WEP64|ZD_RX_WEP128|ZD_RX_WEP256))
            hdr->rt_flags |= IEEE80211_RADIOTAP_F_WEP;

      hdr->rt_rate = stats->rate / 5;

      /* FIXME: 802.11a */
      hdr->rt_channel = cpu_to_le16(ieee80211chan2mhz(
                                         _zd_chip_get_channel(&mac->chip)));
      hdr->rt_chbitmask = cpu_to_le16(IEEE80211_CHAN_2GHZ |
            ((status->frame_status & ZD_RX_FRAME_MODULATION_MASK) ==
            ZD_RX_OFDM ? IEEE80211_CHAN_OFDM : IEEE80211_CHAN_CCK));
}

/* Returns 1 if the data packet is for us and 0 otherwise. */
static int is_data_packet_for_us(struct ieee80211_device *ieee,
                               struct ieee80211_hdr_4addr *hdr)
{
      struct net_device *netdev = ieee->dev;
      u16 fc = le16_to_cpu(hdr->frame_ctl);

      ZD_ASSERT(WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA);

      switch (ieee->iw_mode) {
      case IW_MODE_ADHOC:
            if ((fc & (IEEE80211_FCTL_TODS|IEEE80211_FCTL_FROMDS)) != 0 ||
                compare_ether_addr(hdr->addr3, ieee->bssid) != 0)
                  return 0;
            break;
      case IW_MODE_AUTO:
      case IW_MODE_INFRA:
            if ((fc & (IEEE80211_FCTL_TODS|IEEE80211_FCTL_FROMDS)) !=
                IEEE80211_FCTL_FROMDS ||
                compare_ether_addr(hdr->addr2, ieee->bssid) != 0)
                  return 0;
            break;
      default:
            ZD_ASSERT(ieee->iw_mode != IW_MODE_MONITOR);
            return 0;
      }

      return compare_ether_addr(hdr->addr1, netdev->dev_addr) == 0 ||
             (is_multicast_ether_addr(hdr->addr1) &&
            compare_ether_addr(hdr->addr3, netdev->dev_addr) != 0) ||
             (netdev->flags & IFF_PROMISC);
}

/* Filters received packets. The function returns 1 if the packet should be
 * forwarded to ieee80211_rx(). If the packet should be ignored the function
 * returns 0. If an invalid packet is found the function returns -EINVAL.
 *
 * The function calls ieee80211_rx_mgt() directly.
 *
 * It has been based on ieee80211_rx_any.
 */
static int filter_rx(struct ieee80211_device *ieee,
                   const u8 *buffer, unsigned int length,
                 struct ieee80211_rx_stats *stats)
{
      struct ieee80211_hdr_4addr *hdr;
      u16 fc;

      if (ieee->iw_mode == IW_MODE_MONITOR)
            return 1;

      hdr = (struct ieee80211_hdr_4addr *)buffer;
      fc = le16_to_cpu(hdr->frame_ctl);
      if ((fc & IEEE80211_FCTL_VERS) != 0)
            return -EINVAL;

      switch (WLAN_FC_GET_TYPE(fc)) {
      case IEEE80211_FTYPE_MGMT:
            if (length < sizeof(struct ieee80211_hdr_3addr))
                  return -EINVAL;
            ieee80211_rx_mgt(ieee, hdr, stats);
            return 0;
      case IEEE80211_FTYPE_CTL:
            return 0;
      case IEEE80211_FTYPE_DATA:
            /* Ignore invalid short buffers */
            if (length < sizeof(struct ieee80211_hdr_3addr))
                  return -EINVAL;
            return is_data_packet_for_us(ieee, hdr);
      }

      return -EINVAL;
}

static void update_qual_rssi(struct zd_mac *mac,
                       const u8 *buffer, unsigned int length,
                       u8 qual_percent, u8 rssi_percent)
{
      unsigned long flags;
      struct ieee80211_hdr_3addr *hdr;
      int i;

      hdr = (struct ieee80211_hdr_3addr *)buffer;
      if (length < offsetof(struct ieee80211_hdr_3addr, addr3))
            return;
      if (compare_ether_addr(hdr->addr2, zd_mac_to_ieee80211(mac)->bssid) != 0)
            return;

      spin_lock_irqsave(&mac->lock, flags);
      i = mac->stats_count % ZD_MAC_STATS_BUFFER_SIZE;
      mac->qual_buffer[i] = qual_percent;
      mac->rssi_buffer[i] = rssi_percent;
      mac->stats_count++;
      spin_unlock_irqrestore(&mac->lock, flags);
}

static int fill_rx_stats(struct ieee80211_rx_stats *stats,
                       const struct rx_status **pstatus,
                     struct zd_mac *mac,
                   const u8 *buffer, unsigned int length)
{
      const struct rx_status *status;

      *pstatus = status = (struct rx_status *)
            (buffer + (length - sizeof(struct rx_status)));
      if (status->frame_status & ZD_RX_ERROR) {
            struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);
            ieee->stats.rx_errors++;
            if (status->frame_status & ZD_RX_TIMEOUT_ERROR)
                  ieee->stats.rx_missed_errors++;
            else if (status->frame_status & ZD_RX_FIFO_OVERRUN_ERROR)
                  ieee->stats.rx_fifo_errors++;
            else if (status->frame_status & ZD_RX_DECRYPTION_ERROR)
                  ieee->ieee_stats.rx_discards_undecryptable++;
            else if (status->frame_status & ZD_RX_CRC32_ERROR) {
                  ieee->stats.rx_crc_errors++;
                  ieee->ieee_stats.rx_fcs_errors++;
            }
            else if (status->frame_status & ZD_RX_CRC16_ERROR)
                  ieee->stats.rx_crc_errors++;
            return -EINVAL;
      }

      memset(stats, 0, sizeof(struct ieee80211_rx_stats));
      stats->len = length - (ZD_PLCP_HEADER_SIZE + IEEE80211_FCS_LEN +
                           + sizeof(struct rx_status));
      /* FIXME: 802.11a */
      stats->freq = IEEE80211_24GHZ_BAND;
      stats->received_channel = _zd_chip_get_channel(&mac->chip);
      stats->rssi = zd_rx_strength_percent(status->signal_strength);
      stats->signal = zd_rx_qual_percent(buffer,
                                      length - sizeof(struct rx_status),
                                      status);
      stats->mask = IEEE80211_STATMASK_RSSI | IEEE80211_STATMASK_SIGNAL;
      stats->rate = zd_rx_rate(buffer, status);
      if (stats->rate)
            stats->mask |= IEEE80211_STATMASK_RATE;

      return 0;
}

static void zd_mac_rx(struct zd_mac *mac, struct sk_buff *skb)
{
      int r;
      struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);
      struct ieee80211_rx_stats stats;
      const struct rx_status *status;

      if (skb->len < ZD_PLCP_HEADER_SIZE + IEEE80211_1ADDR_LEN +
                     IEEE80211_FCS_LEN + sizeof(struct rx_status))
      {
            ieee->stats.rx_errors++;
            ieee->stats.rx_length_errors++;
            goto free_skb;
      }

      r = fill_rx_stats(&stats, &status, mac, skb->data, skb->len);
      if (r) {
            /* Only packets with rx errors are included here.
             * The error stats have already been set in fill_rx_stats.
             */
            goto free_skb;
      }

      __skb_pull(skb, ZD_PLCP_HEADER_SIZE);
      __skb_trim(skb, skb->len -
                    (IEEE80211_FCS_LEN + sizeof(struct rx_status)));

      ZD_ASSERT(IS_ALIGNED((unsigned long)skb->data, 4));

      update_qual_rssi(mac, skb->data, skb->len, stats.signal,
                     status->signal_strength);

      r = filter_rx(ieee, skb->data, skb->len, &stats);
      if (r <= 0) {
            if (r < 0) {
                  ieee->stats.rx_errors++;
                  dev_dbg_f(zd_mac_dev(mac), "Error in packet.\n");
            }
            goto free_skb;
      }

      if (ieee->iw_mode == IW_MODE_MONITOR)
            fill_rt_header(skb_push(skb, sizeof(struct zd_rt_hdr)), mac,
                         &stats, status);

      r = ieee80211_rx(ieee, skb, &stats);
      if (r)
            return;
free_skb:
      /* We are always in a soft irq. */
      dev_kfree_skb(skb);
}

static void do_rx(unsigned long mac_ptr)
{
      struct zd_mac *mac = (struct zd_mac *)mac_ptr;
      struct sk_buff *skb;

      while ((skb = skb_dequeue(&mac->rx_queue)) != NULL)
            zd_mac_rx(mac, skb);
}

int zd_mac_rx_irq(struct zd_mac *mac, const u8 *buffer, unsigned int length)
{
      struct sk_buff *skb;
      unsigned int reserved =
            ALIGN(max_t(unsigned int,
                        sizeof(struct zd_rt_hdr), ZD_PLCP_HEADER_SIZE), 4) -
            ZD_PLCP_HEADER_SIZE;

      skb = dev_alloc_skb(reserved + length);
      if (!skb) {
            struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);
            dev_warn(zd_mac_dev(mac), "Could not allocate skb.\n");
            ieee->stats.rx_dropped++;
            return -ENOMEM;
      }
      skb_reserve(skb, reserved);
      memcpy(__skb_put(skb, length), buffer, length);
      skb_queue_tail(&mac->rx_queue, skb);
      tasklet_schedule(&mac->rx_tasklet);
      return 0;
}

static int netdev_tx(struct ieee80211_txb *txb, struct net_device *netdev,
                 int pri)
{
      return zd_mac_tx(zd_netdev_mac(netdev), txb, pri);
}

static void set_security(struct net_device *netdev,
                   struct ieee80211_security *sec)
{
      struct ieee80211_device *ieee = zd_netdev_ieee80211(netdev);
      struct ieee80211_security *secinfo = &ieee->sec;
      int keyidx;

      dev_dbg_f(zd_mac_dev(zd_netdev_mac(netdev)), "\n");

      for (keyidx = 0; keyidx<WEP_KEYS; keyidx++)
            if (sec->flags & (1<<keyidx)) {
                  secinfo->encode_alg[keyidx] = sec->encode_alg[keyidx];
                  secinfo->key_sizes[keyidx] = sec->key_sizes[keyidx];
                  memcpy(secinfo->keys[keyidx], sec->keys[keyidx],
                         SCM_KEY_LEN);
            }

      if (sec->flags & SEC_ACTIVE_KEY) {
            secinfo->active_key = sec->active_key;
            dev_dbg_f(zd_mac_dev(zd_netdev_mac(netdev)),
                  "   .active_key = %d\n", sec->active_key);
      }
      if (sec->flags & SEC_UNICAST_GROUP) {
            secinfo->unicast_uses_group = sec->unicast_uses_group;
            dev_dbg_f(zd_mac_dev(zd_netdev_mac(netdev)),
                  "   .unicast_uses_group = %d\n",
                  sec->unicast_uses_group);
      }
      if (sec->flags & SEC_LEVEL) {
            secinfo->level = sec->level;
            dev_dbg_f(zd_mac_dev(zd_netdev_mac(netdev)),
                  "   .level = %d\n", sec->level);
      }
      if (sec->flags & SEC_ENABLED) {
            secinfo->enabled = sec->enabled;
            dev_dbg_f(zd_mac_dev(zd_netdev_mac(netdev)),
                  "   .enabled = %d\n", sec->enabled);
      }
      if (sec->flags & SEC_ENCRYPT) {
            secinfo->encrypt = sec->encrypt;
            dev_dbg_f(zd_mac_dev(zd_netdev_mac(netdev)),
                  "   .encrypt = %d\n", sec->encrypt);
      }
      if (sec->flags & SEC_AUTH_MODE) {
            secinfo->auth_mode = sec->auth_mode;
            dev_dbg_f(zd_mac_dev(zd_netdev_mac(netdev)),
                  "   .auth_mode = %d\n", sec->auth_mode);
      }
}

static void ieee_init(struct ieee80211_device *ieee)
{
      ieee->mode = IEEE_B | IEEE_G;
      ieee->freq_band = IEEE80211_24GHZ_BAND;
      ieee->modulation = IEEE80211_OFDM_MODULATION | IEEE80211_CCK_MODULATION;
      ieee->tx_headroom = sizeof(struct zd_ctrlset);
      ieee->set_security = set_security;
      ieee->hard_start_xmit = netdev_tx;

      /* Software encryption/decryption for now */
      ieee->host_build_iv = 0;
      ieee->host_encrypt = 1;
      ieee->host_decrypt = 1;

      /* FIXME: default to managed mode, until ieee80211 and zd1211rw can
       * correctly support AUTO */
      ieee->iw_mode = IW_MODE_INFRA;
}

static void softmac_init(struct ieee80211softmac_device *sm)
{
      sm->set_channel = set_channel;
      sm->bssinfo_change = bssinfo_change;
}

struct iw_statistics *zd_mac_get_wireless_stats(struct net_device *ndev)
{
      struct zd_mac *mac = zd_netdev_mac(ndev);
      struct iw_statistics *iw_stats = &mac->iw_stats;
      unsigned int i, count, qual_total, rssi_total;

      memset(iw_stats, 0, sizeof(struct iw_statistics));
      /* We are not setting the status, because ieee->state is not updated
       * at all and this driver doesn't track authentication state.
       */
      spin_lock_irq(&mac->lock);
      count = mac->stats_count < ZD_MAC_STATS_BUFFER_SIZE ?
            mac->stats_count : ZD_MAC_STATS_BUFFER_SIZE;
      qual_total = rssi_total = 0;
      for (i = 0; i < count; i++) {
            qual_total += mac->qual_buffer[i];
            rssi_total += mac->rssi_buffer[i];
      }
      spin_unlock_irq(&mac->lock);
      iw_stats->qual.updated = IW_QUAL_NOISE_INVALID;
      if (count > 0) {
            iw_stats->qual.qual = qual_total / count;
            iw_stats->qual.level = rssi_total / count;
            iw_stats->qual.updated |=
                  IW_QUAL_QUAL_UPDATED|IW_QUAL_LEVEL_UPDATED;
      } else {
            iw_stats->qual.updated |=
                  IW_QUAL_QUAL_INVALID|IW_QUAL_LEVEL_INVALID;
      }
      /* TODO: update counter */
      return iw_stats;
}

#define LINK_LED_WORK_DELAY HZ

static void link_led_handler(struct work_struct *work)
{
      struct zd_mac *mac =
            container_of(work, struct zd_mac, housekeeping.link_led_work.work);
      struct zd_chip *chip = &mac->chip;
      struct ieee80211softmac_device *sm = ieee80211_priv(mac->netdev);
      int is_associated;
      int r;

      spin_lock_irq(&mac->lock);
      is_associated = sm->associnfo.associated != 0;
      spin_unlock_irq(&mac->lock);

      r = zd_chip_control_leds(chip,
                             is_associated ? LED_ASSOCIATED : LED_SCANNING);
      if (r)
            dev_err(zd_mac_dev(mac), "zd_chip_control_leds error %d\n", r);

      queue_delayed_work(zd_workqueue, &mac->housekeeping.link_led_work,
                       LINK_LED_WORK_DELAY);
}

static void housekeeping_init(struct zd_mac *mac)
{
      INIT_DELAYED_WORK(&mac->housekeeping.link_led_work, link_led_handler);
}

static void housekeeping_enable(struct zd_mac *mac)
{
      dev_dbg_f(zd_mac_dev(mac), "\n");
      queue_delayed_work(zd_workqueue, &mac->housekeeping.link_led_work,
                     0);
}

static void housekeeping_disable(struct zd_mac *mac)
{
      dev_dbg_f(zd_mac_dev(mac), "\n");
      cancel_rearming_delayed_workqueue(zd_workqueue,
            &mac->housekeeping.link_led_work);
      zd_chip_control_leds(&mac->chip, LED_OFF);
}

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