--- /dev/null
+/*
+ * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
+ *
+ * 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.
+ *
+ * Based on minstrel.c:
+ * Copyright (C) 2005-2007 Derek Smithies <derek@indranet.co.nz>
+ * Sponsored by Indranet Technologies Ltd
+ *
+ * Based on sample.c:
+ * Copyright (c) 2005 John Bicket
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer,
+ * without modification.
+ * 2. Redistributions in binary form must reproduce at minimum a disclaimer
+ * similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
+ * redistribution must be conditioned upon including a substantially
+ * similar Disclaimer requirement for further binary redistribution.
+ * 3. Neither the names of the above-listed copyright holders nor the names
+ * of any contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * NO WARRANTY
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
+ * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+ * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGES.
+ */
+#include <linux/netdevice.h>
+#include <linux/types.h>
+#include <linux/skbuff.h>
+#include <linux/debugfs.h>
+#include <linux/random.h>
+#include <linux/ieee80211.h>
+#include <linux/slab.h>
+#include <net/mac80211.h>
+#include "rate.h"
+#include "rc80211_minstrel.h"
+
+#define SAMPLE_TBL(_mi, _idx, _col) \
+ _mi->sample_table[(_idx * SAMPLE_COLUMNS) + _col]
+
+/* convert mac80211 rate index to local array index */
+static inline int
+rix_to_ndx(struct minstrel_sta_info *mi, int rix)
+{
+ int i = rix;
+ for (i = rix; i >= 0; i--)
+ if (mi->r[i].rix == rix)
+ break;
+ return i;
+}
+
+/* return current EMWA throughput */
+int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_ewma)
+{
+ int usecs;
+
+ usecs = mr->perfect_tx_time;
+ if (!usecs)
+ usecs = 1000000;
+
+ /* reset thr. below 10% success */
+ if (mr->stats.prob_ewma < MINSTREL_FRAC(10, 100))
+ return 0;
+
+ if (prob_ewma > MINSTREL_FRAC(90, 100))
+ return MINSTREL_TRUNC(100000 * (MINSTREL_FRAC(90, 100) / usecs));
+ else
+ return MINSTREL_TRUNC(100000 * (prob_ewma / usecs));
+}
+
+/* find & sort topmost throughput rates */
+static inline void
+minstrel_sort_best_tp_rates(struct minstrel_sta_info *mi, int i, u8 *tp_list)
+{
+ int j = MAX_THR_RATES;
+ struct minstrel_rate_stats *tmp_mrs = &mi->r[j - 1].stats;
+ struct minstrel_rate_stats *cur_mrs = &mi->r[i].stats;
+
+ while (j > 0 && (minstrel_get_tp_avg(&mi->r[i], cur_mrs->prob_ewma) >
+ minstrel_get_tp_avg(&mi->r[tp_list[j - 1]], tmp_mrs->prob_ewma))) {
+ j--;
+ tmp_mrs = &mi->r[tp_list[j - 1]].stats;
+ }
+
+ if (j < MAX_THR_RATES - 1)
+ memmove(&tp_list[j + 1], &tp_list[j], MAX_THR_RATES - (j + 1));
+ if (j < MAX_THR_RATES)
+ tp_list[j] = i;
+}
+
+static void
+minstrel_set_rate(struct minstrel_sta_info *mi, struct ieee80211_sta_rates *ratetbl,
+ int offset, int idx)
+{
+ struct minstrel_rate *r = &mi->r[idx];
+
+ ratetbl->rate[offset].idx = r->rix;
+ ratetbl->rate[offset].count = r->adjusted_retry_count;
+ ratetbl->rate[offset].count_cts = r->retry_count_cts;
+ ratetbl->rate[offset].count_rts = r->stats.retry_count_rtscts;
+}
+
+static void
+minstrel_update_rates(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
+{
+ struct ieee80211_sta_rates *ratetbl;
+ int i = 0;
+
+ ratetbl = kzalloc(sizeof(*ratetbl), GFP_ATOMIC);
+ if (!ratetbl)
+ return;
+
+ /* Start with max_tp_rate */
+ minstrel_set_rate(mi, ratetbl, i++, mi->max_tp_rate[0]);
+
+ if (mp->hw->max_rates >= 3) {
+ /* At least 3 tx rates supported, use max_tp_rate2 next */
+ minstrel_set_rate(mi, ratetbl, i++, mi->max_tp_rate[1]);
+ }
+
+ if (mp->hw->max_rates >= 2) {
+ /* At least 2 tx rates supported, use max_prob_rate next */
+ minstrel_set_rate(mi, ratetbl, i++, mi->max_prob_rate);
+ }
+
+ /* Use lowest rate last */
+ ratetbl->rate[i].idx = mi->lowest_rix;
+ ratetbl->rate[i].count = mp->max_retry;
+ ratetbl->rate[i].count_cts = mp->max_retry;
+ ratetbl->rate[i].count_rts = mp->max_retry;
+
+ rate_control_set_rates(mp->hw, mi->sta, ratetbl);
+}
+
+/*
+* Recalculate statistics and counters of a given rate
+*/
+void
+minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs)
+{
+ if (unlikely(mrs->attempts > 0)) {
+ mrs->sample_skipped = 0;
+ mrs->cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
+ if (unlikely(!mrs->att_hist)) {
+ mrs->prob_ewma = mrs->cur_prob;
+ } else {
+ /* update exponential weighted moving variance */
+ mrs->prob_ewmsd = minstrel_ewmsd(mrs->prob_ewmsd,
+ mrs->cur_prob,
+ mrs->prob_ewma,
+ EWMA_LEVEL);
+
+ /*update exponential weighted moving avarage */
+ mrs->prob_ewma = minstrel_ewma(mrs->prob_ewma,
+ mrs->cur_prob,
+ EWMA_LEVEL);
+ }
+ mrs->att_hist += mrs->attempts;
+ mrs->succ_hist += mrs->success;
+ } else {
+ mrs->sample_skipped++;
+ }
+
+ mrs->last_success = mrs->success;
+ mrs->last_attempts = mrs->attempts;
+ mrs->success = 0;
+ mrs->attempts = 0;
+}
+
+static void
+minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
+{
+ u8 tmp_tp_rate[MAX_THR_RATES];
+ u8 tmp_prob_rate = 0;
+ int i, tmp_cur_tp, tmp_prob_tp;
+
+ for (i = 0; i < MAX_THR_RATES; i++)
+ tmp_tp_rate[i] = 0;
+
+ for (i = 0; i < mi->n_rates; i++) {
+ struct minstrel_rate *mr = &mi->r[i];
+ struct minstrel_rate_stats *mrs = &mi->r[i].stats;
+ struct minstrel_rate_stats *tmp_mrs = &mi->r[tmp_prob_rate].stats;
+
+ /* Update statistics of success probability per rate */
+ minstrel_calc_rate_stats(mrs);
+
+ /* Sample less often below the 10% chance of success.
+ * Sample less often above the 95% chance of success. */
+ if (mrs->prob_ewma > MINSTREL_FRAC(95, 100) ||
+ mrs->prob_ewma < MINSTREL_FRAC(10, 100)) {
+ mr->adjusted_retry_count = mrs->retry_count >> 1;
+ if (mr->adjusted_retry_count > 2)
+ mr->adjusted_retry_count = 2;
+ mr->sample_limit = 4;
+ } else {
+ mr->sample_limit = -1;
+ mr->adjusted_retry_count = mrs->retry_count;
+ }
+ if (!mr->adjusted_retry_count)
+ mr->adjusted_retry_count = 2;
+
+ minstrel_sort_best_tp_rates(mi, i, tmp_tp_rate);
+
+ /* To determine the most robust rate (max_prob_rate) used at
+ * 3rd mmr stage we distinct between two cases:
+ * (1) if any success probabilitiy >= 95%, out of those rates
+ * choose the maximum throughput rate as max_prob_rate
+ * (2) if all success probabilities < 95%, the rate with
+ * highest success probability is chosen as max_prob_rate */
+ if (mrs->prob_ewma >= MINSTREL_FRAC(95, 100)) {
+ tmp_cur_tp = minstrel_get_tp_avg(mr, mrs->prob_ewma);
+ tmp_prob_tp = minstrel_get_tp_avg(&mi->r[tmp_prob_rate],
+ tmp_mrs->prob_ewma);
+ if (tmp_cur_tp >= tmp_prob_tp)
+ tmp_prob_rate = i;
+ } else {
+ if (mrs->prob_ewma >= tmp_mrs->prob_ewma)
+ tmp_prob_rate = i;
+ }
+ }
+
+ /* Assign the new rate set */
+ memcpy(mi->max_tp_rate, tmp_tp_rate, sizeof(mi->max_tp_rate));
+ mi->max_prob_rate = tmp_prob_rate;
+
+#ifdef CONFIG_MAC80211_DEBUGFS
+ /* use fixed index if set */
+ if (mp->fixed_rate_idx != -1) {
+ mi->max_tp_rate[0] = mp->fixed_rate_idx;
+ mi->max_tp_rate[1] = mp->fixed_rate_idx;
+ mi->max_prob_rate = mp->fixed_rate_idx;
+ }
+#endif
+
+ /* Reset update timer */
+ mi->last_stats_update = jiffies;
+
+ minstrel_update_rates(mp, mi);
+}
+
+static void
+minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
+ struct ieee80211_sta *sta, void *priv_sta,
+ struct ieee80211_tx_info *info)
+{
+ struct minstrel_priv *mp = priv;
+ struct minstrel_sta_info *mi = priv_sta;
+ struct ieee80211_tx_rate *ar = info->status.rates;
+ int i, ndx;
+ int success;
+
+ success = !!(info->flags & IEEE80211_TX_STAT_ACK);
+
+ for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
+ if (ar[i].idx < 0)
+ break;
+
+ ndx = rix_to_ndx(mi, ar[i].idx);
+ if (ndx < 0)
+ continue;
+
+ mi->r[ndx].stats.attempts += ar[i].count;
+
+ if ((i != IEEE80211_TX_MAX_RATES - 1) && (ar[i + 1].idx < 0))
+ mi->r[ndx].stats.success += success;
+ }
+
+ if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
+ mi->sample_packets++;
+
+ if (mi->sample_deferred > 0)
+ mi->sample_deferred--;
+
+ if (time_after(jiffies, mi->last_stats_update +
+ (mp->update_interval * HZ) / 1000))
+ minstrel_update_stats(mp, mi);
+}
+
+
+static inline unsigned int
+minstrel_get_retry_count(struct minstrel_rate *mr,
+ struct ieee80211_tx_info *info)
+{
+ u8 retry = mr->adjusted_retry_count;
+
+ if (info->control.use_rts)
+ retry = max_t(u8, 2, min(mr->stats.retry_count_rtscts, retry));
+ else if (info->control.use_cts_prot)
+ retry = max_t(u8, 2, min(mr->retry_count_cts, retry));
+ return retry;
+}
+
+
+static int
+minstrel_get_next_sample(struct minstrel_sta_info *mi)
+{
+ unsigned int sample_ndx;
+ sample_ndx = SAMPLE_TBL(mi, mi->sample_row, mi->sample_column);
+ mi->sample_row++;
+ if ((int) mi->sample_row >= mi->n_rates) {
+ mi->sample_row = 0;
+ mi->sample_column++;
+ if (mi->sample_column >= SAMPLE_COLUMNS)
+ mi->sample_column = 0;
+ }
+ return sample_ndx;
+}
+
+static void
+minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
+ void *priv_sta, struct ieee80211_tx_rate_control *txrc)
+{
+ struct sk_buff *skb = txrc->skb;
+ struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+ struct minstrel_sta_info *mi = priv_sta;
+ struct minstrel_priv *mp = priv;
+ struct ieee80211_tx_rate *rate = &info->control.rates[0];
+ struct minstrel_rate *msr, *mr;
+ unsigned int ndx;
+ bool mrr_capable;
+ bool prev_sample;
+ int delta;
+ int sampling_ratio;
+
+ /* management/no-ack frames do not use rate control */
+ if (rate_control_send_low(sta, priv_sta, txrc))
+ return;
+
+ /* check multi-rate-retry capabilities & adjust lookaround_rate */
+ mrr_capable = mp->has_mrr &&
+ !txrc->rts &&
+ !txrc->bss_conf->use_cts_prot;
+ if (mrr_capable)
+ sampling_ratio = mp->lookaround_rate_mrr;
+ else
+ sampling_ratio = mp->lookaround_rate;
+
+ /* increase sum packet counter */
+ mi->total_packets++;
+
+#ifdef CONFIG_MAC80211_DEBUGFS
+ if (mp->fixed_rate_idx != -1)
+ return;
+#endif
+
+ delta = (mi->total_packets * sampling_ratio / 100) -
+ (mi->sample_packets + mi->sample_deferred / 2);
+
+ /* delta < 0: no sampling required */
+ prev_sample = mi->prev_sample;
+ mi->prev_sample = false;
+ if (delta < 0 || (!mrr_capable && prev_sample))
+ return;
+
+ if (mi->total_packets >= 10000) {
+ mi->sample_deferred = 0;
+ mi->sample_packets = 0;
+ mi->total_packets = 0;
+ } else if (delta > mi->n_rates * 2) {
+ /* With multi-rate retry, not every planned sample
+ * attempt actually gets used, due to the way the retry
+ * chain is set up - [max_tp,sample,prob,lowest] for
+ * sample_rate < max_tp.
+ *
+ * If there's too much sampling backlog and the link
+ * starts getting worse, minstrel would start bursting
+ * out lots of sampling frames, which would result
+ * in a large throughput loss. */
+ mi->sample_packets += (delta - mi->n_rates * 2);
+ }
+
+ /* get next random rate sample */
+ ndx = minstrel_get_next_sample(mi);
+ msr = &mi->r[ndx];
+ mr = &mi->r[mi->max_tp_rate[0]];
+
+ /* Decide if direct ( 1st mrr stage) or indirect (2nd mrr stage)
+ * rate sampling method should be used.
+ * Respect such rates that are not sampled for 20 interations.
+ */
+ if (mrr_capable &&
+ msr->perfect_tx_time > mr->perfect_tx_time &&
+ msr->stats.sample_skipped < 20) {
+ /* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
+ * packets that have the sampling rate deferred to the
+ * second MRR stage. Increase the sample counter only
+ * if the deferred sample rate was actually used.
+ * Use the sample_deferred counter to make sure that
+ * the sampling is not done in large bursts */
+ info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
+ rate++;
+ mi->sample_deferred++;
+ } else {
+ if (!msr->sample_limit)
+ return;
+
+ mi->sample_packets++;
+ if (msr->sample_limit > 0)
+ msr->sample_limit--;
+ }
+
+ /* If we're not using MRR and the sampling rate already
+ * has a probability of >95%, we shouldn't be attempting
+ * to use it, as this only wastes precious airtime */
+ if (!mrr_capable &&
+ (mi->r[ndx].stats.prob_ewma > MINSTREL_FRAC(95, 100)))
+ return;
+
+ mi->prev_sample = true;
+
+ rate->idx = mi->r[ndx].rix;
+ rate->count = minstrel_get_retry_count(&mi->r[ndx], info);
+}
+
+
+static void
+calc_rate_durations(enum ieee80211_band band,
+ struct minstrel_rate *d,
+ struct ieee80211_rate *rate,
+ struct cfg80211_chan_def *chandef)
+{
+ int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
+ int shift = ieee80211_chandef_get_shift(chandef);
+
+ d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
+ DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
+ shift);
+ d->ack_time = ieee80211_frame_duration(band, 10,
+ DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
+ shift);
+}
+
+static void
+init_sample_table(struct minstrel_sta_info *mi)
+{
+ unsigned int i, col, new_idx;
+ u8 rnd[8];
+
+ mi->sample_column = 0;
+ mi->sample_row = 0;
+ memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates);
+
+ for (col = 0; col < SAMPLE_COLUMNS; col++) {
+ prandom_bytes(rnd, sizeof(rnd));
+ for (i = 0; i < mi->n_rates; i++) {
+ new_idx = (i + rnd[i & 7]) % mi->n_rates;
+ while (SAMPLE_TBL(mi, new_idx, col) != 0xff)
+ new_idx = (new_idx + 1) % mi->n_rates;
+
+ SAMPLE_TBL(mi, new_idx, col) = i;
+ }
+ }
+}
+
+static void
+minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
+ struct cfg80211_chan_def *chandef,
+ struct ieee80211_sta *sta, void *priv_sta)
+{
+ struct minstrel_sta_info *mi = priv_sta;
+ struct minstrel_priv *mp = priv;
+ struct ieee80211_rate *ctl_rate;
+ unsigned int i, n = 0;
+ unsigned int t_slot = 9; /* FIXME: get real slot time */
+ u32 rate_flags;
+
+ mi->sta = sta;
+ mi->lowest_rix = rate_lowest_index(sband, sta);
+ ctl_rate = &sband->bitrates[mi->lowest_rix];
+ mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
+ ctl_rate->bitrate,
+ !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1,
+ ieee80211_chandef_get_shift(chandef));
+
+ rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
+ memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate));
+ mi->max_prob_rate = 0;
+
+ for (i = 0; i < sband->n_bitrates; i++) {
+ struct minstrel_rate *mr = &mi->r[n];
+ struct minstrel_rate_stats *mrs = &mi->r[n].stats;
+ unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
+ unsigned int tx_time_single;
+ unsigned int cw = mp->cw_min;
+ int shift;
+
+ if (!rate_supported(sta, sband->band, i))
+ continue;
+ if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
+ continue;
+
+ n++;
+ memset(mr, 0, sizeof(*mr));
+ memset(mrs, 0, sizeof(*mrs));
+
+ mr->rix = i;
+ shift = ieee80211_chandef_get_shift(chandef);
+ mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
+ (1 << shift) * 5);
+ calc_rate_durations(sband->band, mr, &sband->bitrates[i],
+ chandef);
+
+ /* calculate maximum number of retransmissions before
+ * fallback (based on maximum segment size) */
+ mr->sample_limit = -1;
+ mrs->retry_count = 1;
+ mr->retry_count_cts = 1;
+ mrs->retry_count_rtscts = 1;
+ tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
+ do {
+ /* add one retransmission */
+ tx_time_single = mr->ack_time + mr->perfect_tx_time;
+
+ /* contention window */
+ tx_time_single += (t_slot * cw) >> 1;
+ cw = min((cw << 1) | 1, mp->cw_max);
+
+ tx_time += tx_time_single;
+ tx_time_cts += tx_time_single + mi->sp_ack_dur;
+ tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
+ if ((tx_time_cts < mp->segment_size) &&
+ (mr->retry_count_cts < mp->max_retry))
+ mr->retry_count_cts++;
+ if ((tx_time_rtscts < mp->segment_size) &&
+ (mrs->retry_count_rtscts < mp->max_retry))
+ mrs->retry_count_rtscts++;
+ } while ((tx_time < mp->segment_size) &&
+ (++mr->stats.retry_count < mp->max_retry));
+ mr->adjusted_retry_count = mrs->retry_count;
+ if (!(sband->bitrates[i].flags & IEEE80211_RATE_ERP_G))
+ mr->retry_count_cts = mrs->retry_count;
+ }
+
+ for (i = n; i < sband->n_bitrates; i++) {
+ struct minstrel_rate *mr = &mi->r[i];
+ mr->rix = -1;
+ }
+
+ mi->n_rates = n;
+ mi->last_stats_update = jiffies;
+
+ init_sample_table(mi);
+ minstrel_update_rates(mp, mi);
+}
+
+static void *
+minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
+{
+ struct ieee80211_supported_band *sband;
+ struct minstrel_sta_info *mi;
+ struct minstrel_priv *mp = priv;
+ struct ieee80211_hw *hw = mp->hw;
+ int max_rates = 0;
+ int i;
+
+ mi = kzalloc(sizeof(struct minstrel_sta_info), gfp);
+ if (!mi)
+ return NULL;
+
+ for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
+ sband = hw->wiphy->bands[i];
+ if (sband && sband->n_bitrates > max_rates)
+ max_rates = sband->n_bitrates;
+ }
+
+ mi->r = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
+ if (!mi->r)
+ goto error;
+
+ mi->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
+ if (!mi->sample_table)
+ goto error1;
+
+ mi->last_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_init_cck_rates(struct minstrel_priv *mp)
+{
+ static const int bitrates[4] = { 10, 20, 55, 110 };
+ struct ieee80211_supported_band *sband;
+ u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
+ int i, j;
+
+ sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ];
+ if (!sband)
+ return;
+
+ for (i = 0, j = 0; i < sband->n_bitrates; i++) {
+ struct ieee80211_rate *rate = &sband->bitrates[i];
+
+ if (rate->flags & IEEE80211_RATE_ERP_G)
+ continue;
+
+ if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
+ continue;
+
+ for (j = 0; j < ARRAY_SIZE(bitrates); j++) {
+ if (rate->bitrate != bitrates[j])
+ continue;
+
+ mp->cck_rates[j] = i;
+ break;
+ }
+ }
+}
+
+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;
+
+ /* 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;
+
+#ifdef CONFIG_MAC80211_DEBUGFS
+ mp->fixed_rate_idx = (u32) -1;
+ mp->dbg_fixed_rate = debugfs_create_u32("fixed_rate_idx",
+ S_IRUGO | S_IWUGO, debugfsdir, &mp->fixed_rate_idx);
+#endif
+
+ minstrel_init_cck_rates(mp);
+
+ return mp;
+}
+
+static void
+minstrel_free(void *priv)
+{
+#ifdef CONFIG_MAC80211_DEBUGFS
+ debugfs_remove(((struct minstrel_priv *)priv)->dbg_fixed_rate);
+#endif
+ kfree(priv);
+}
+
+static u32 minstrel_get_expected_throughput(void *priv_sta)
+{
+ struct minstrel_sta_info *mi = priv_sta;
+ struct minstrel_rate_stats *tmp_mrs;
+ int idx = mi->max_tp_rate[0];
+ int tmp_cur_tp;
+
+ /* convert pkt per sec in kbps (1200 is the average pkt size used for
+ * computing cur_tp
+ */
+ tmp_mrs = &mi->r[idx].stats;
+ tmp_cur_tp = minstrel_get_tp_avg(&mi->r[idx], tmp_mrs->prob_ewma);
+ tmp_cur_tp = tmp_cur_tp * 1200 * 8 / 1024;
+
+ return tmp_cur_tp;
+}
+
+const struct rate_control_ops mac80211_minstrel = {
+ .name = "minstrel",
+ .tx_status_noskb = 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
+ .get_expected_throughput = minstrel_get_expected_throughput,
+};
+
+int __init
+rc80211_minstrel_init(void)
+{
+ return ieee80211_rate_control_register(&mac80211_minstrel);
+}
+
+void
+rc80211_minstrel_exit(void)
+{
+ ieee80211_rate_control_unregister(&mac80211_minstrel);
+}
+
Code Review / kvmfornfv.git / blobdiff