path: root/net/mac80211/ht.c

/*
 * HT handling
 *
 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
 * Copyright 2007-2008, Intel Corporation
 *
 * 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.
 */

#include <linux/ieee80211.h>
#include <net/wireless.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "sta_info.h"
#include "wme.h"

void ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_supported_band *sband,
				       struct ieee80211_ht_cap *ht_cap_ie,
				       struct ieee80211_sta_ht_cap *ht_cap)
{
	u8 ampdu_info, tx_mcs_set_cap;
	int i, max_tx_streams;

	BUG_ON(!ht_cap);

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

	if (!ht_cap_ie)
		return;

	ht_cap->ht_supported = true;

	ht_cap->cap = le16_to_cpu(ht_cap_ie->cap_info) & sband->ht_cap.cap;
	ht_cap->cap &= ~IEEE80211_HT_CAP_SM_PS;
	ht_cap->cap |= sband->ht_cap.cap & IEEE80211_HT_CAP_SM_PS;

	ampdu_info = ht_cap_ie->ampdu_params_info;
	ht_cap->ampdu_factor =
		ampdu_info & IEEE80211_HT_AMPDU_PARM_FACTOR;
	ht_cap->ampdu_density =
		(ampdu_info & IEEE80211_HT_AMPDU_PARM_DENSITY) >> 2;

	/* own MCS TX capabilities */
	tx_mcs_set_cap = sband->ht_cap.mcs.tx_params;

	/* can we TX with MCS rates? */
	if (!(tx_mcs_set_cap & IEEE80211_HT_MCS_TX_DEFINED))
		return;

	/* Counting from 0, therefore +1 */
	if (tx_mcs_set_cap & IEEE80211_HT_MCS_TX_RX_DIFF)
		max_tx_streams =
			((tx_mcs_set_cap & IEEE80211_HT_MCS_TX_MAX_STREAMS_MASK)
				>> IEEE80211_HT_MCS_TX_MAX_STREAMS_SHIFT) + 1;
	else
		max_tx_streams = IEEE80211_HT_MCS_TX_MAX_STREAMS;

	/*
	 * 802.11n D5.0 20.3.5 / 20.6 says:
	 * - indices 0 to 7 and 32 are single spatial stream
	 * - 8 to 31 are multiple spatial streams using equal modulation
	 *   [8..15 for two streams, 16..23 for three and 24..31 for four]
	 * - remainder are multiple spatial streams using unequal modulation
	 */
	for (i = 0; i < max_tx_streams; i++)
		ht_cap->mcs.rx_mask[i] =
			sband->ht_cap.mcs.rx_mask[i] & ht_cap_ie->mcs.rx_mask[i];

	if (tx_mcs_set_cap & IEEE80211_HT_MCS_TX_UNEQUAL_MODULATION)
		for (i = IEEE80211_HT_MCS_UNEQUAL_MODULATION_START_BYTE;
		     i < IEEE80211_HT_MCS_MASK_LEN; i++)
			ht_cap->mcs.rx_mask[i] =
				sband->ht_cap.mcs.rx_mask[i] &
					ht_cap_ie->mcs.rx_mask[i];

	/* handle MCS rate 32 too */
	if (sband->ht_cap.mcs.rx_mask[32/8] & ht_cap_ie->mcs.rx_mask[32/8] & 1)
		ht_cap->mcs.rx_mask[32/8] |= 1;
}

/*
 * ieee80211_enable_ht should be called only after the operating band
 * has been determined as ht configuration depends on the hw's
 * HT abilities for a specific band.
 */
u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
			struct ieee80211_ht_info *hti,
			u16 ap_ht_cap_flags)
{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_supported_band *sband;
	struct ieee80211_bss_ht_conf ht;
	u32 changed = 0;
	bool enable_ht = true, ht_changed;
	enum nl80211_channel_type channel_type = NL80211_CHAN_NO_HT;

	sband = local->hw.wiphy->bands[local->hw.conf.channel->band];

	memset(&ht, 0, sizeof(ht));

	/* HT is not supported */
	if (!sband->ht_cap.ht_supported)
		enable_ht = false;

	/* check that channel matches the right operating channel */
	if (local->hw.conf.channel->center_freq !=
	    ieee80211_channel_to_frequency(hti->control_chan))
		enable_ht = false;

	if (enable_ht) {
		channel_type = NL80211_CHAN_HT20;

		if (!(ap_ht_cap_flags & IEEE80211_HT_CAP_40MHZ_INTOLERANT) &&
		    (sband->ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) &&
		    (hti->ht_param & IEEE80211_HT_PARAM_CHAN