drivers/net/wireless/rt2x00/rt2x00ht.c

   1 /*
   2         Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
   3         <http://rt2x00.serialmonkey.com>
   4
   5         This program is free software; you can redistribute it and/or modify
   6         it under the terms of the GNU General Public License as published by
   7         the Free Software Foundation; either version 2 of the License, or
   8         (at your option) any later version.
   9
  10         This program is distributed in the hope that it will be useful,
  11         but WITHOUT ANY WARRANTY; without even the implied warranty of
  12         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13         GNU General Public License for more details.
  14
  15         You should have received a copy of the GNU General Public License
  16         along with this program; if not, write to the
  17         Free Software Foundation, Inc.,
  18         59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 /*
  22         Module: rt2x00lib
  23         Abstract: rt2x00 HT specific routines.
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28
  29 #include "rt2x00.h"
  30 #include "rt2x00lib.h"
  31
  32 void rt2x00ht_create_tx_descriptor(struct queue_entry *entry,
  33                                    struct txentry_desc *txdesc,
  34                                    const struct rt2x00_rate *hwrate)
  35 {
  36         struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(entry->skb);
  37         struct ieee80211_tx_rate *txrate = &tx_info->control.rates[0];
  38         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)entry->skb->data;
  39
  40         if (tx_info->control.sta)
  41                 txdesc->u.ht.mpdu_density =
  42                     tx_info->control.sta->ht_cap.ampdu_density;
  43
  44         txdesc->u.ht.ba_size = 7;       /* FIXME: What value is needed? */
  45
  46         txdesc->u.ht.stbc =
  47             (tx_info->flags & IEEE80211_TX_CTL_STBC) >> IEEE80211_TX_CTL_STBC_SHIFT;
  48
  49         /*
  50          * If IEEE80211_TX_RC_MCS is set txrate->idx just contains the
  51          * mcs rate to be used
  52          */
  53         if (txrate->flags & IEEE80211_TX_RC_MCS) {
  54                 txdesc->u.ht.mcs = txrate->idx;
  55
  56                 /*
  57                  * MIMO PS should be set to 1 for STA's using dynamic SM PS
  58                  * when using more then one tx stream (>MCS7).
  59                  */
  60                 if (tx_info->control.sta && txdesc->u.ht.mcs > 7 &&
  61                     ((tx_info->control.sta->ht_cap.cap &
  62                       IEEE80211_HT_CAP_SM_PS) >>
  63                      IEEE80211_HT_CAP_SM_PS_SHIFT) ==
  64                     WLAN_HT_CAP_SM_PS_DYNAMIC)
  65                         __set_bit(ENTRY_TXD_HT_MIMO_PS, &txdesc->flags);
  66         } else {
  67                 txdesc->u.ht.mcs = rt2x00_get_rate_mcs(hwrate->mcs);
  68                 if (txrate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE)
  69                         txdesc->u.ht.mcs |= 0x08;
  70         }
  71
  72         /*
  73          * This frame is eligible for an AMPDU, however, don't aggregate
  74          * frames that are intended to probe a specific tx rate.
  75          */
  76         if (tx_info->flags & IEEE80211_TX_CTL_AMPDU &&
  77             !(tx_info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE))
  78                 __set_bit(ENTRY_TXD_HT_AMPDU, &txdesc->flags);
  79
  80         /*
  81          * Set 40Mhz mode if necessary (for legacy rates this will
  82          * duplicate the frame to both channels).
  83          */
  84         if (txrate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH ||
  85             txrate->flags & IEEE80211_TX_RC_DUP_DATA)
  86                 __set_bit(ENTRY_TXD_HT_BW_40, &txdesc->flags);
  87         if (txrate->flags & IEEE80211_TX_RC_SHORT_GI)
  88                 __set_bit(ENTRY_TXD_HT_SHORT_GI, &txdesc->flags);
  89
  90         /*
  91          * Determine IFS values
  92          * - Use TXOP_BACKOFF for management frames
  93          * - Use TXOP_SIFS for fragment bursts
  94          * - Use TXOP_HTTXOP for everything else
  95          *
  96          * Note: rt2800 devices won't use CTS protection (if used)
  97          * for frames not transmitted with TXOP_HTTXOP
  98          */
  99         if (ieee80211_is_mgmt(hdr->frame_control))
 100                 txdesc->u.ht.txop = TXOP_BACKOFF;
 101         else if (!(tx_info->flags & IEEE80211_TX_CTL_FIRST_FRAGMENT))
 102                 txdesc->u.ht.txop = TXOP_SIFS;
 103         else
 104                 txdesc->u.ht.txop = TXOP_HTTXOP;
 105 }
 106
 107 u16 rt2x00ht_center_channel(struct rt2x00_dev *rt2x00dev,
 108                             struct ieee80211_conf *conf)
 109 {
 110         struct hw_mode_spec *spec = &rt2x00dev->spec;
 111         int center_channel;
 112         u16 i;
 113
 114         /*
 115          * Initialize center channel to current channel.
 116          */
 117         center_channel = spec->channels[conf->channel->hw_value].channel;
 118
 119         /*
 120          * Adjust center channel to HT40+ and HT40- operation.
 121          */
 122         if (conf_is_ht40_plus(conf))
 123                 center_channel += 2;
 124         else if (conf_is_ht40_minus(conf))
 125                 center_channel -= (center_channel == 14) ? 1 : 2;
 126
 127         for (i = 0; i < spec->num_channels; i++)
 128                 if (spec->channels[i].channel == center_channel)
 129                         return i;
 130
 131         WARN_ON(1);
 132         return conf->channel->hw_value;
 133 }