LXR linux/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
  32void 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->mpdu_density =
  42                    tx_info->control.sta->ht_cap.ampdu_density;
  43
  44        txdesc->ba_size = 7;    /* FIXME: What value is needed? */
  45
  46        txdesc->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->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->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->mcs = rt2x00_get_rate_mcs(hwrate->mcs);
  68                if (txrate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE)
  69                        txdesc->mcs |= 0x08;
  70        }
  71
  72
  73        /*
  74         * This frame is eligible for an AMPDU, however, don't aggregate
  75         * frames that are intended to probe a specific tx rate.
  76         */
  77        if (tx_info->flags & IEEE80211_TX_CTL_AMPDU &&
  78            !(tx_info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE))
  79                __set_bit(ENTRY_TXD_HT_AMPDU, &txdesc->flags);
  80
  81        /*
  82         * Determine HT Mix/Greenfield rate mode
  83         */
  84        if (txrate->flags & IEEE80211_TX_RC_MCS)
  85                txdesc->rate_mode = RATE_MODE_HT_MIX;
  86        if (txrate->flags & IEEE80211_TX_RC_GREEN_FIELD)
  87                txdesc->rate_mode = RATE_MODE_HT_GREENFIELD;
  88
  89        /*
  90         * Set 40Mhz mode if necessary (for legacy rates this will
  91         * duplicate the frame to both channels).
  92         */
  93        if (txrate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH ||
  94            txrate->flags & IEEE80211_TX_RC_DUP_DATA)
  95                __set_bit(ENTRY_TXD_HT_BW_40, &txdesc->flags);
  96        if (txrate->flags & IEEE80211_TX_RC_SHORT_GI)
  97                __set_bit(ENTRY_TXD_HT_SHORT_GI, &txdesc->flags);
  98
  99        /*
 100         * Determine IFS values
 101         * - Use TXOP_BACKOFF for management frames
 102         * - Use TXOP_SIFS for fragment bursts
 103         * - Use TXOP_HTTXOP for everything else
 104         *
 105         * Note: rt2800 devices won't use CTS protection (if used)
 106         * for frames not transmitted with TXOP_HTTXOP
 107         */
 108        if (ieee80211_is_mgmt(hdr->frame_control))
 109                txdesc->txop = TXOP_BACKOFF;
 110        else if (!(tx_info->flags & IEEE80211_TX_CTL_FIRST_FRAGMENT))
 111                txdesc->txop = TXOP_SIFS;
 112        else
 113                txdesc->txop = TXOP_HTTXOP;
 114}
 115
 116u16 rt2x00ht_center_channel(struct rt2x00_dev *rt2x00dev,
 117                            struct ieee80211_conf *conf)
 118{
 119        struct hw_mode_spec *spec = &rt2x00dev->spec;
 120        int center_channel;
 121        u16 i;
 122
 123        /*
 124         * Initialize center channel to current channel.
 125         */
 126        center_channel = spec->channels[conf->channel->hw_value].channel;
 127
 128        /*
 129         * Adjust center channel to HT40+ and HT40- operation.
 130         */
 131        if (conf_is_ht40_plus(conf))
 132                center_channel += 2;
 133        else if (conf_is_ht40_minus(conf))
 134                center_channel -= (center_channel == 14) ? 1 : 2;
 135
 136        for (i = 0; i < spec->num_channels; i++)
 137                if (spec->channels[i].channel == center_channel)
 138                        return i;
 139
 140        WARN_ON(1);
 141        return conf->channel->hw_value;
 142}
 143