572 строки
16 KiB
C
572 строки
16 KiB
C
/*
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* Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Based on minstrel.c:
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* Copyright (C) 2005-2007 Derek Smithies <derek@indranet.co.nz>
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* Sponsored by Indranet Technologies Ltd
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*
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* Based on sample.c:
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* Copyright (c) 2005 John Bicket
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer,
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* without modification.
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* 2. Redistributions in binary form must reproduce at minimum a disclaimer
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* similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
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* redistribution must be conditioned upon including a substantially
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* similar Disclaimer requirement for further binary redistribution.
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* 3. Neither the names of the above-listed copyright holders nor the names
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* of any contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* NO WARRANTY
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
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* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
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* IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGES.
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*/
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#include <linux/netdevice.h>
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#include <linux/types.h>
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#include <linux/skbuff.h>
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#include <linux/debugfs.h>
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#include <linux/random.h>
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#include <linux/ieee80211.h>
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#include <linux/slab.h>
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#include <net/mac80211.h>
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#include "rate.h"
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#include "rc80211_minstrel.h"
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#define SAMPLE_COLUMNS 10
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#define SAMPLE_TBL(_mi, _idx, _col) \
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_mi->sample_table[(_idx * SAMPLE_COLUMNS) + _col]
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/* convert mac80211 rate index to local array index */
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static inline int
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rix_to_ndx(struct minstrel_sta_info *mi, int rix)
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{
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int i = rix;
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for (i = rix; i >= 0; i--)
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if (mi->r[i].rix == rix)
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break;
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WARN_ON(i < 0);
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return i;
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}
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static void
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minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
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{
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u32 max_tp = 0, index_max_tp = 0, index_max_tp2 = 0;
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u32 max_prob = 0, index_max_prob = 0;
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u32 usecs;
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u32 p;
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int i;
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mi->stats_update = jiffies;
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for (i = 0; i < mi->n_rates; i++) {
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struct minstrel_rate *mr = &mi->r[i];
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usecs = mr->perfect_tx_time;
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if (!usecs)
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usecs = 1000000;
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/* To avoid rounding issues, probabilities scale from 0 (0%)
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* to 18000 (100%) */
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if (mr->attempts) {
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p = (mr->success * 18000) / mr->attempts;
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mr->succ_hist += mr->success;
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mr->att_hist += mr->attempts;
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mr->cur_prob = p;
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p = ((p * (100 - mp->ewma_level)) + (mr->probability *
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mp->ewma_level)) / 100;
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mr->probability = p;
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mr->cur_tp = p * (1000000 / usecs);
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}
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mr->last_success = mr->success;
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mr->last_attempts = mr->attempts;
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mr->success = 0;
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mr->attempts = 0;
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/* Sample less often below the 10% chance of success.
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* Sample less often above the 95% chance of success. */
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if ((mr->probability > 17100) || (mr->probability < 1800)) {
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mr->adjusted_retry_count = mr->retry_count >> 1;
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if (mr->adjusted_retry_count > 2)
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mr->adjusted_retry_count = 2;
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mr->sample_limit = 4;
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} else {
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mr->sample_limit = -1;
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mr->adjusted_retry_count = mr->retry_count;
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}
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if (!mr->adjusted_retry_count)
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mr->adjusted_retry_count = 2;
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}
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for (i = 0; i < mi->n_rates; i++) {
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struct minstrel_rate *mr = &mi->r[i];
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if (max_tp < mr->cur_tp) {
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index_max_tp = i;
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max_tp = mr->cur_tp;
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}
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if (max_prob < mr->probability) {
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index_max_prob = i;
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max_prob = mr->probability;
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}
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}
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max_tp = 0;
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for (i = 0; i < mi->n_rates; i++) {
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struct minstrel_rate *mr = &mi->r[i];
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if (i == index_max_tp)
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continue;
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if (max_tp < mr->cur_tp) {
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index_max_tp2 = i;
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max_tp = mr->cur_tp;
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}
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}
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mi->max_tp_rate = index_max_tp;
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mi->max_tp_rate2 = index_max_tp2;
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mi->max_prob_rate = index_max_prob;
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}
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static void
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minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
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struct ieee80211_sta *sta, void *priv_sta,
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struct sk_buff *skb)
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{
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struct minstrel_sta_info *mi = priv_sta;
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struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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struct ieee80211_tx_rate *ar = info->status.rates;
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int i, ndx;
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int success;
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success = !!(info->flags & IEEE80211_TX_STAT_ACK);
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for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
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if (ar[i].idx < 0)
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break;
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ndx = rix_to_ndx(mi, ar[i].idx);
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if (ndx < 0)
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continue;
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mi->r[ndx].attempts += ar[i].count;
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if ((i != IEEE80211_TX_MAX_RATES - 1) && (ar[i + 1].idx < 0))
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mi->r[ndx].success += success;
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}
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if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
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mi->sample_count++;
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if (mi->sample_deferred > 0)
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mi->sample_deferred--;
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}
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static inline unsigned int
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minstrel_get_retry_count(struct minstrel_rate *mr,
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struct ieee80211_tx_info *info)
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{
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unsigned int retry = mr->adjusted_retry_count;
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if (info->control.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
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retry = max(2U, min(mr->retry_count_rtscts, retry));
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else if (info->control.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT)
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retry = max(2U, min(mr->retry_count_cts, retry));
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return retry;
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}
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static int
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minstrel_get_next_sample(struct minstrel_sta_info *mi)
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{
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unsigned int sample_ndx;
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sample_ndx = SAMPLE_TBL(mi, mi->sample_idx, mi->sample_column);
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mi->sample_idx++;
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if ((int) mi->sample_idx > (mi->n_rates - 2)) {
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mi->sample_idx = 0;
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mi->sample_column++;
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if (mi->sample_column >= SAMPLE_COLUMNS)
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mi->sample_column = 0;
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}
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return sample_ndx;
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}
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static void
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minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
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void *priv_sta, struct ieee80211_tx_rate_control *txrc)
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{
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struct sk_buff *skb = txrc->skb;
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struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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struct minstrel_sta_info *mi = priv_sta;
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struct minstrel_priv *mp = priv;
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struct ieee80211_tx_rate *ar = info->control.rates;
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unsigned int ndx, sample_ndx = 0;
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bool mrr;
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bool sample_slower = false;
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bool sample = false;
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int i, delta;
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int mrr_ndx[3];
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int sample_rate;
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if (rate_control_send_low(sta, priv_sta, txrc))
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return;
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mrr = mp->has_mrr && !txrc->rts && !txrc->bss_conf->use_cts_prot;
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if (time_after(jiffies, mi->stats_update + (mp->update_interval *
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HZ) / 1000))
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minstrel_update_stats(mp, mi);
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ndx = mi->max_tp_rate;
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if (mrr)
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sample_rate = mp->lookaround_rate_mrr;
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else
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sample_rate = mp->lookaround_rate;
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mi->packet_count++;
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delta = (mi->packet_count * sample_rate / 100) -
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(mi->sample_count + mi->sample_deferred / 2);
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/* delta > 0: sampling required */
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if ((delta > 0) && (mrr || !mi->prev_sample)) {
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struct minstrel_rate *msr;
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if (mi->packet_count >= 10000) {
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mi->sample_deferred = 0;
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mi->sample_count = 0;
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mi->packet_count = 0;
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} else if (delta > mi->n_rates * 2) {
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/* With multi-rate retry, not every planned sample
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* attempt actually gets used, due to the way the retry
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* chain is set up - [max_tp,sample,prob,lowest] for
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* sample_rate < max_tp.
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*
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* If there's too much sampling backlog and the link
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* starts getting worse, minstrel would start bursting
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* out lots of sampling frames, which would result
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* in a large throughput loss. */
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mi->sample_count += (delta - mi->n_rates * 2);
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}
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sample_ndx = minstrel_get_next_sample(mi);
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msr = &mi->r[sample_ndx];
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sample = true;
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sample_slower = mrr && (msr->perfect_tx_time >
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mi->r[ndx].perfect_tx_time);
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if (!sample_slower) {
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if (msr->sample_limit != 0) {
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ndx = sample_ndx;
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mi->sample_count++;
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if (msr->sample_limit > 0)
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msr->sample_limit--;
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} else {
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sample = false;
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}
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} else {
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/* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
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* packets that have the sampling rate deferred to the
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* second MRR stage. Increase the sample counter only
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* if the deferred sample rate was actually used.
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* Use the sample_deferred counter to make sure that
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* the sampling is not done in large bursts */
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info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
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mi->sample_deferred++;
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}
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}
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mi->prev_sample = sample;
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/* If we're not using MRR and the sampling rate already
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* has a probability of >95%, we shouldn't be attempting
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* to use it, as this only wastes precious airtime */
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if (!mrr && sample && (mi->r[ndx].probability > 17100))
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ndx = mi->max_tp_rate;
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ar[0].idx = mi->r[ndx].rix;
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ar[0].count = minstrel_get_retry_count(&mi->r[ndx], info);
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if (!mrr) {
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if (!sample)
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ar[0].count = mp->max_retry;
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ar[1].idx = mi->lowest_rix;
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ar[1].count = mp->max_retry;
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return;
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}
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/* MRR setup */
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if (sample) {
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if (sample_slower)
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mrr_ndx[0] = sample_ndx;
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else
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mrr_ndx[0] = mi->max_tp_rate;
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} else {
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mrr_ndx[0] = mi->max_tp_rate2;
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}
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mrr_ndx[1] = mi->max_prob_rate;
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mrr_ndx[2] = 0;
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for (i = 1; i < 4; i++) {
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ar[i].idx = mi->r[mrr_ndx[i - 1]].rix;
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ar[i].count = mi->r[mrr_ndx[i - 1]].adjusted_retry_count;
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}
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}
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static void
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calc_rate_durations(struct minstrel_sta_info *mi, struct ieee80211_local *local,
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struct minstrel_rate *d, struct ieee80211_rate *rate)
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{
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int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
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d->perfect_tx_time = ieee80211_frame_duration(local, 1200,
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rate->bitrate, erp, 1);
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d->ack_time = ieee80211_frame_duration(local, 10,
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rate->bitrate, erp, 1);
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}
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static void
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init_sample_table(struct minstrel_sta_info *mi)
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{
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unsigned int i, col, new_idx;
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unsigned int n_srates = mi->n_rates - 1;
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u8 rnd[8];
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mi->sample_column = 0;
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mi->sample_idx = 0;
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memset(mi->sample_table, 0, SAMPLE_COLUMNS * mi->n_rates);
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for (col = 0; col < SAMPLE_COLUMNS; col++) {
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for (i = 0; i < n_srates; i++) {
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get_random_bytes(rnd, sizeof(rnd));
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new_idx = (i + rnd[i & 7]) % n_srates;
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while (SAMPLE_TBL(mi, new_idx, col) != 0)
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new_idx = (new_idx + 1) % n_srates;
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/* Don't sample the slowest rate (i.e. slowest base
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* rate). We must presume that the slowest rate works
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* fine, or else other management frames will also be
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* failing and the link will break */
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SAMPLE_TBL(mi, new_idx, col) = i + 1;
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}
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}
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}
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static void
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minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
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struct ieee80211_sta *sta, void *priv_sta)
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{
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struct minstrel_sta_info *mi = priv_sta;
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struct minstrel_priv *mp = priv;
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struct ieee80211_local *local = hw_to_local(mp->hw);
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struct ieee80211_rate *ctl_rate;
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unsigned int i, n = 0;
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unsigned int t_slot = 9; /* FIXME: get real slot time */
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mi->lowest_rix = rate_lowest_index(sband, sta);
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ctl_rate = &sband->bitrates[mi->lowest_rix];
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mi->sp_ack_dur = ieee80211_frame_duration(local, 10, ctl_rate->bitrate,
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!!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1);
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for (i = 0; i < sband->n_bitrates; i++) {
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struct minstrel_rate *mr = &mi->r[n];
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unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
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unsigned int tx_time_single;
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unsigned int cw = mp->cw_min;
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if (!rate_supported(sta, sband->band, i))
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continue;
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n++;
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memset(mr, 0, sizeof(*mr));
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mr->rix = i;
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mr->bitrate = sband->bitrates[i].bitrate / 5;
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calc_rate_durations(mi, local, mr,
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&sband->bitrates[i]);
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/* calculate maximum number of retransmissions before
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* fallback (based on maximum segment size) */
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mr->sample_limit = -1;
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mr->retry_count = 1;
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mr->retry_count_cts = 1;
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mr->retry_count_rtscts = 1;
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tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
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do {
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/* add one retransmission */
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tx_time_single = mr->ack_time + mr->perfect_tx_time;
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/* contention window */
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tx_time_single += t_slot + min(cw, mp->cw_max);
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cw = (cw << 1) | 1;
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tx_time += tx_time_single;
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tx_time_cts += tx_time_single + mi->sp_ack_dur;
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tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
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if ((tx_time_cts < mp->segment_size) &&
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(mr->retry_count_cts < mp->max_retry))
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mr->retry_count_cts++;
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if ((tx_time_rtscts < mp->segment_size) &&
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(mr->retry_count_rtscts < mp->max_retry))
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mr->retry_count_rtscts++;
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} while ((tx_time < mp->segment_size) &&
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(++mr->retry_count < mp->max_retry));
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mr->adjusted_retry_count = mr->retry_count;
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}
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for (i = n; i < sband->n_bitrates; i++) {
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struct minstrel_rate *mr = &mi->r[i];
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mr->rix = -1;
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}
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mi->n_rates = n;
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mi->stats_update = jiffies;
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init_sample_table(mi);
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}
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static void *
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minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
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{
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struct ieee80211_supported_band *sband;
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struct minstrel_sta_info *mi;
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struct minstrel_priv *mp = priv;
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struct ieee80211_hw *hw = mp->hw;
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int max_rates = 0;
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int i;
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mi = kzalloc(sizeof(struct minstrel_sta_info), gfp);
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if (!mi)
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return NULL;
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for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
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sband = hw->wiphy->bands[i];
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if (sband && sband->n_bitrates > max_rates)
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max_rates = sband->n_bitrates;
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}
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mi->r = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
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if (!mi->r)
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goto error;
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|
mi->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
|
|
if (!mi->sample_table)
|
|
goto error1;
|
|
|
|
mi->stats_update = jiffies;
|
|
return mi;
|
|
|
|
error1:
|
|
kfree(mi->r);
|
|
error:
|
|
kfree(mi);
|
|
return NULL;
|
|
}
|
|
|
|
static void
|
|
minstrel_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
|
|
{
|
|
struct minstrel_sta_info *mi = priv_sta;
|
|
|
|
kfree(mi->sample_table);
|
|
kfree(mi->r);
|
|
kfree(mi);
|
|
}
|
|
|
|
static void *
|
|
minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
|
|
{
|
|
struct minstrel_priv *mp;
|
|
|
|
mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
|
|
if (!mp)
|
|
return NULL;
|
|
|
|
/* contention window settings
|
|
* Just an approximation. Using the per-queue values would complicate
|
|
* the calculations and is probably unnecessary */
|
|
mp->cw_min = 15;
|
|
mp->cw_max = 1023;
|
|
|
|
/* number of packets (in %) to use for sampling other rates
|
|
* sample less often for non-mrr packets, because the overhead
|
|
* is much higher than with mrr */
|
|
mp->lookaround_rate = 5;
|
|
mp->lookaround_rate_mrr = 10;
|
|
|
|
/* moving average weight for EWMA */
|
|
mp->ewma_level = 75;
|
|
|
|
/* maximum time that the hw is allowed to stay in one MRR segment */
|
|
mp->segment_size = 6000;
|
|
|
|
if (hw->max_rate_tries > 0)
|
|
mp->max_retry = hw->max_rate_tries;
|
|
else
|
|
/* safe default, does not necessarily have to match hw properties */
|
|
mp->max_retry = 7;
|
|
|
|
if (hw->max_rates >= 4)
|
|
mp->has_mrr = true;
|
|
|
|
mp->hw = hw;
|
|
mp->update_interval = 100;
|
|
|
|
return mp;
|
|
}
|
|
|
|
static void
|
|
minstrel_free(void *priv)
|
|
{
|
|
kfree(priv);
|
|
}
|
|
|
|
struct rate_control_ops mac80211_minstrel = {
|
|
.name = "minstrel",
|
|
.tx_status = minstrel_tx_status,
|
|
.get_rate = minstrel_get_rate,
|
|
.rate_init = minstrel_rate_init,
|
|
.alloc = minstrel_alloc,
|
|
.free = minstrel_free,
|
|
.alloc_sta = minstrel_alloc_sta,
|
|
.free_sta = minstrel_free_sta,
|
|
#ifdef CONFIG_MAC80211_DEBUGFS
|
|
.add_sta_debugfs = minstrel_add_sta_debugfs,
|
|
.remove_sta_debugfs = minstrel_remove_sta_debugfs,
|
|
#endif
|
|
};
|
|
|
|
int __init
|
|
rc80211_minstrel_init(void)
|
|
{
|
|
return ieee80211_rate_control_register(&mac80211_minstrel);
|
|
}
|
|
|
|
void
|
|
rc80211_minstrel_exit(void)
|
|
{
|
|
ieee80211_rate_control_unregister(&mac80211_minstrel);
|
|
}
|
|
|