/*
 * Return current throughput based on the average A-MPDU length, taking into
 * account the expected number of retransmissions and their expected length
 */
int
minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate,
		       int prob_ewma)
{
	unsigned int nsecs = 0;

	/* do not account throughput if sucess prob is below 10% */
	if (prob_ewma < MINSTREL_FRAC(10, 100))
		return 0;

	if (group != MINSTREL_CCK_GROUP)
		nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);

	nsecs += minstrel_mcs_groups[group].duration[rate];

	/*
	 * For the throughput calculation, limit the probability value to 90% to
	 * account for collision related packet error rate fluctuation
	 * (prob is scaled - see MINSTREL_FRAC above)
	 */
	if (prob_ewma > MINSTREL_FRAC(90, 100))
		return MINSTREL_TRUNC(100000 * ((MINSTREL_FRAC(90, 100) * 1000)
								      / nsecs));
	else
		return MINSTREL_TRUNC(100000 * ((prob_ewma * 1000) / nsecs));
}

/*
 * Calculate throughput based on the average A-MPDU length, taking into account
 * the expected number of retransmissions and their expected length
 */
static void
minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
{
	struct minstrel_rate_stats *mr;
	unsigned int nsecs = 0;
	unsigned int tp;
	unsigned int prob;

	mr = &mi->groups[group].rates[rate];
	prob = mr->probability;

	if (prob < MINSTREL_FRAC(1, 10)) {
		mr->cur_tp = 0;
		return;
	}

	/*
	 * For the throughput calculation, limit the probability value to 90% to
	 * account for collision related packet error rate fluctuation
	 */
	if (prob > MINSTREL_FRAC(9, 10))
		prob = MINSTREL_FRAC(9, 10);

	if (group != MINSTREL_CCK_GROUP)
		nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);

	nsecs += minstrel_mcs_groups[group].duration[rate];
	tp = 1000000 * ((prob * 1000) / nsecs);

	mr->cur_tp = MINSTREL_TRUNC(tp);
}

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 {

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;
	u32 usecs;
	int i;

	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;

		usecs = mr->perfect_tx_time;
		if (!usecs)
			usecs = 1000000;

		if (unlikely(mrs->attempts > 0)) {
			mrs->sample_skipped = 0;
			mrs->cur_prob = MINSTREL_FRAC(mrs->success,
						      mrs->attempts);
			mrs->succ_hist += mrs->success;
			mrs->att_hist += mrs->attempts;
			mrs->probability = minstrel_ewma(mrs->probability,
							 mrs->cur_prob,
							 EWMA_LEVEL);
		} else
			mrs->sample_skipped++;

		mrs->last_success = mrs->success;
		mrs->last_attempts = mrs->attempts;
		mrs->success = 0;
		mrs->attempts = 0;

		/* Update throughput per rate, reset thr. below 10% success */
		if (mrs->probability < MINSTREL_FRAC(10, 100))
			mrs->cur_tp = 0;
		else
			mrs->cur_tp = mrs->probability * (1000000 / usecs);

		/* Sample less often below the 10% chance of success.
		 * Sample less often above the 95% chance of success. */
		if (mrs->probability > MINSTREL_FRAC(95, 100) ||
		    mrs->probability < 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 {

static int
minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
{
	int group = mi->max_prob_rate / MCS_GROUP_RATES;
	const struct mcs_group *g = &minstrel_mcs_groups[group];
	int rate = mi->max_prob_rate % MCS_GROUP_RATES;
	unsigned int duration;

	/* Disable A-MSDU if max_prob_rate is bad */
	if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100))
		return 1;

	duration = g->duration[rate];
	duration <<= g->shift;

	/* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
	if (duration > MCS_DURATION(1, 0, 52))
		return 500;

	/*
	 * If the rate is slower than single-stream MCS4, limit A-MSDU to usual
	 * data packet size
	 */
	if (duration > MCS_DURATION(1, 0, 104))
		return 1600;

	/*
	 * If the rate is slower than single-stream MCS7, or if the max throughput
	 * rate success probability is less than 75%, limit A-MSDU to twice the usual
	 * data packet size
	 */
	if (duration > MCS_DURATION(1, 0, 260) ||
	    (minstrel_ht_get_prob_ewma(mi, mi->max_tp_rate[0]) <
	     MINSTREL_FRAC(75, 100)))
		return 3200;

	/*
	 * HT A-MPDU limits maximum MPDU size under BA agreement to 4095 bytes.
	 * Since aggregation sessions are started/stopped without txq flush, use
	 * the limit here to avoid the complexity of having to de-aggregate
	 * packets in the queue.
	 */
	if (!mi->sta->vht_cap.vht_supported)
		return IEEE80211_MAX_MPDU_LEN_HT_BA;

	/* unlimited */
	return 0;
}

/*
* 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;
}

/*
 * Find and set the topmost probability rate per sta and per group
 */
static void
minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
{
	struct minstrel_mcs_group_data *mg;
	struct minstrel_rate_stats *mr;
	int tmp_group, tmp_idx, tmp_tp, tmp_prob, max_tp_group;

	mg = &mi->groups[index / MCS_GROUP_RATES];
	mr = &mg->rates[index % MCS_GROUP_RATES];

	tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
	tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
	tmp_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;

	/* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
	 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
	max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
	if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
	    (max_tp_group != MINSTREL_CCK_GROUP))
		return;

	if (mr->probability > MINSTREL_FRAC(75, 100)) {
		if (mr->cur_tp > tmp_tp)
			mi->max_prob_rate = index;
		if (mr->cur_tp > mg->rates[mg->max_group_prob_rate].cur_tp)
			mg->max_group_prob_rate = index;
	} else {
		if (mr->probability > tmp_prob)
			mi->max_prob_rate = index;
		if (mr->probability > mg->rates[mg->max_group_prob_rate].probability)
			mg->max_group_prob_rate = index;
	}
}

static int
minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
	struct minstrel_rate_stats *mr;
	struct minstrel_mcs_group_data *mg;
	unsigned int sample_dur, sample_group;
	int sample_idx = 0;

	if (mi->sample_wait > 0) {
		mi->sample_wait--;
		return -1;
	}

	if (!mi->sample_tries)
		return -1;

	mg = &mi->groups[mi->sample_group];
	sample_idx = sample_table[mg->column][mg->index];
	mr = &mg->rates[sample_idx];
	sample_group = mi->sample_group;
	sample_idx += sample_group * MCS_GROUP_RATES;
	minstrel_next_sample_idx(mi);

	/*
	 * Sampling might add some overhead (RTS, no aggregation)
	 * to the frame. Hence, don't use sampling for the currently
	 * used rates.
	 */
	if (sample_idx == mi->max_tp_rate ||
	    sample_idx == mi->max_tp_rate2 ||
	    sample_idx == mi->max_prob_rate)
		return -1;

	/*
	 * Do not sample if the probability is already higher than 95%
	 * to avoid wasting airtime.
	 */
	if (mr->probability > MINSTREL_FRAC(95, 100))
		return -1;

	/*
	 * Make sure that lower rates get sampled only occasionally,
	 * if the link is working perfectly.
	 */
	sample_dur = minstrel_get_duration(sample_idx);
	if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
	    (mi->max_prob_streams <
	     minstrel_mcs_groups[sample_group].streams ||
	     sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
		if (mr->sample_skipped < 20)
			return -1;

		if (mi->sample_slow++ > 2)
			return -1;
	}
	mi->sample_tries--;

	return sample_idx;
}

/* 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));
}

static void
minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
			struct cfg80211_chan_def *chandef,
                        struct ieee80211_sta *sta, void *priv_sta)
{
	struct minstrel_priv *mp = priv;
	struct minstrel_ht_sta_priv *msp = priv_sta;
	struct minstrel_ht_sta *mi = &msp->ht;
	struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
	u16 ht_cap = sta->ht_cap.cap;
	struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
	int use_vht;
	int n_supported = 0;
	int ack_dur;
	int stbc;
	int i;
	bool ldpc;

	/* fall back to the old minstrel for legacy stations */
	if (!sta->ht_cap.ht_supported)
		goto use_legacy;

	BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);

	if (vht_cap->vht_supported)
		use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
	else
		use_vht = 0;

	msp->is_ht = true;
	memset(mi, 0, sizeof(*mi));

	mi->sta = sta;
	mi->last_stats_update = jiffies;

	ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
	mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
	mi->overhead += ack_dur;
	mi->overhead_rtscts = mi->overhead + 2 * ack_dur;

	mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);

	/* When using MRR, sample more on the first attempt, without delay */
	if (mp->has_mrr) {
		mi->sample_count = 16;
		mi->sample_wait = 0;
	} else {
		mi->sample_count = 8;
		mi->sample_wait = 8;
	}
	mi->sample_tries = 4;

	if (!use_vht) {
		stbc = (ht_cap & IEEE80211_HT_CAP_RX_STBC) >>
			IEEE80211_HT_CAP_RX_STBC_SHIFT;

		ldpc = ht_cap & IEEE80211_HT_CAP_LDPC_CODING;
	} else {

int
minstrel_stats_csv_open(struct inode *inode, struct file *file)
{
	struct minstrel_sta_info *mi = inode->i_private;
	struct minstrel_debugfs_info *ms;
	unsigned int i, tp_max, tp_avg, prob, eprob;
	char *p;

	ms = kmalloc(2048, GFP_KERNEL);
	if (!ms)
		return -ENOMEM;

	file->private_data = ms;
	p = ms->buf;

	for (i = 0; i < mi->n_rates; i++) {
		struct minstrel_rate *mr = &mi->r[i];
		struct minstrel_rate_stats *mrs = &mi->r[i].stats;

		p += sprintf(p, "%s" ,((i == mi->max_tp_rate[0]) ? "A" : ""));
		p += sprintf(p, "%s" ,((i == mi->max_tp_rate[1]) ? "B" : ""));
		p += sprintf(p, "%s" ,((i == mi->max_tp_rate[2]) ? "C" : ""));
		p += sprintf(p, "%s" ,((i == mi->max_tp_rate[3]) ? "D" : ""));
		p += sprintf(p, "%s" ,((i == mi->max_prob_rate) ? "P" : ""));

		p += sprintf(p, ",%u%s", mr->bitrate / 2,
				(mr->bitrate & 1 ? ".5," : ","));
		p += sprintf(p, "%u,", i);
		p += sprintf(p, "%u,",mr->perfect_tx_time);

		tp_max = minstrel_get_tp_avg(mr, MINSTREL_FRAC(100,100));
		tp_avg = minstrel_get_tp_avg(mr, mrs->prob_ewma);
		prob = MINSTREL_TRUNC(mrs->cur_prob * 1000);
		eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);

		p += sprintf(p, "%u.%u,%u.%u,%u.%u,%u.%u,%u.%u,%u,%u,%u,"
				"%llu,%llu,%d,%d\n",
				tp_max / 10, tp_max % 10,
				tp_avg / 10, tp_avg % 10,
				eprob / 10, eprob % 10,
				mrs->prob_ewmsd / 10, mrs->prob_ewmsd % 10,
				prob / 10, prob % 10,
				mrs->retry_count,
				mrs->last_success,
				mrs->last_attempts,
				(unsigned long long)mrs->succ_hist,
				(unsigned long long)mrs->att_hist,
				mi->total_packets - mi->sample_packets,
				mi->sample_packets);

	}
	ms->len = p - ms->buf;

	WARN_ON(ms->len + sizeof(*ms) > 2048);

	return 0;
}

static void
minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
                         int index)
{
	struct minstrel_rate_stats *mrs;
	const struct mcs_group *group;
	unsigned int tx_time, tx_time_rtscts, tx_time_data;
	unsigned int cw = mp->cw_min;
	unsigned int ctime = 0;
	unsigned int t_slot = 9; /* FIXME */
	unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
	unsigned int overhead = 0, overhead_rtscts = 0;

	mrs = minstrel_get_ratestats(mi, index);
	if (mrs->prob_ewma < MINSTREL_FRAC(1, 10)) {
		mrs->retry_count = 1;
		mrs->retry_count_rtscts = 1;
		return;
	}

	mrs->retry_count = 2;
	mrs->retry_count_rtscts = 2;
	mrs->retry_updated = true;

	group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
	tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;

	/* Contention time for first 2 tries */
	ctime = (t_slot * cw) >> 1;
	cw = min((cw << 1) | 1, mp->cw_max);
	ctime += (t_slot * cw) >> 1;
	cw = min((cw << 1) | 1, mp->cw_max);

	if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
		overhead = mi->overhead;
		overhead_rtscts = mi->overhead_rtscts;
	}

	/* Total TX time for data and Contention after first 2 tries */
	tx_time = ctime + 2 * (overhead + tx_time_data);
	tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);

	/* See how many more tries we can fit inside segment size */
	do {
		/* Contention time for this try */
		ctime = (t_slot * cw) >> 1;
		cw = min((cw << 1) | 1, mp->cw_max);

		/* Total TX time after this try */
		tx_time += ctime + overhead + tx_time_data;
		tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;

		if (tx_time_rtscts < mp->segment_size)
			mrs->retry_count_rtscts++;
	} while ((tx_time < mp->segment_size) &&
	         (++mrs->retry_count < mp->max_retry));
}

/*
 * Find and set the topmost probability rate per sta and per group
 */
static void
minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
{
	struct minstrel_mcs_group_data *mg;
	struct minstrel_rate_stats *mrs;
	int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
	int max_tp_group, cur_tp_avg, cur_group, cur_idx;
	int max_gpr_group, max_gpr_idx;
	int max_gpr_tp_avg, max_gpr_prob;

	cur_group = index / MCS_GROUP_RATES;
	cur_idx = index % MCS_GROUP_RATES;
	mg = &mi->groups[index / MCS_GROUP_RATES];
	mrs = &mg->rates[index % MCS_GROUP_RATES];

	tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
	tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
	tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);

	/* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
	 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
	max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
	if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
	    (max_tp_group != MINSTREL_CCK_GROUP))
		return;

	max_gpr_group = mg->max_group_prob_rate / MCS_GROUP_RATES;
	max_gpr_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
	max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_ewma;

	if (mrs->prob_ewma > MINSTREL_FRAC(75, 100)) {
		cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx,
						    mrs->prob_ewma);
		if (cur_tp_avg > tmp_tp_avg)
			mi->max_prob_rate = index;

		max_gpr_tp_avg = minstrel_ht_get_tp_avg(mi, max_gpr_group,
							max_gpr_idx,
							max_gpr_prob);
		if (cur_tp_avg > max_gpr_tp_avg)
			mg->max_group_prob_rate = index;
	} else {
		if (mrs->prob_ewma > tmp_prob)
			mi->max_prob_rate = index;
		if (mrs->prob_ewma > max_gpr_prob)
			mg->max_group_prob_rate = index;
	}
}

static void
minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
                     struct ieee80211_sta_rates *ratetbl, int offset, int index)
{
	const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
	struct minstrel_rate_stats *mrs;
	u8 idx;
	u16 flags = group->flags;

	mrs = minstrel_get_ratestats(mi, index);
	if (!mrs->retry_updated)
		minstrel_calc_retransmit(mp, mi, index);

	if (mrs->prob_ewma < MINSTREL_FRAC(20, 100) || !mrs->retry_count) {
		ratetbl->rate[offset].count = 2;
		ratetbl->rate[offset].count_rts = 2;
		ratetbl->rate[offset].count_cts = 2;
	} else {
		ratetbl->rate[offset].count = mrs->retry_count;
		ratetbl->rate[offset].count_cts = mrs->retry_count;
		ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
	}

	if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
		idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
	else if (flags & IEEE80211_TX_RC_VHT_MCS)
		idx = ((group->streams - 1) << 4) |
		      ((index % MCS_GROUP_RATES) & 0xF);
	else
		idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;

	/* enable RTS/CTS if needed:
	 *  - if station is in dynamic SMPS (and streams > 1)
	 *  - for fallback rates, to increase chances of getting through
	 */
	if (offset > 0 ||
	    (mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
	     group->streams > 1)) {
		ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
		flags |= IEEE80211_TX_RC_USE_RTS_CTS;
	}

	ratetbl->rate[offset].idx = idx;
	ratetbl->rate[offset].flags = flags;
}

/*
 * Recalculate success probabilities and counters for a rate using EWMA
 */
static void
minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
{
	if (unlikely(mr->attempts > 0)) {
		mr->sample_skipped = 0;
		mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
		if (!mr->att_hist)
			mr->probability = mr->cur_prob;
		else
			mr->probability = minstrel_ewma(mr->probability,
				mr->cur_prob, EWMA_LEVEL);
		mr->att_hist += mr->attempts;
		mr->succ_hist += mr->success;
	} else {
		mr->sample_skipped++;
	}
	mr->last_success = mr->success;
	mr->last_attempts = mr->attempts;
	mr->success = 0;
	mr->attempts = 0;
}

static void
minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
                     struct ieee80211_sta_rates *ratetbl, int offset, int index)
{
	const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
	struct minstrel_rate_stats *mr;
	u8 idx;
	u16 flags;

	mr = minstrel_get_ratestats(mi, index);
	if (!mr->retry_updated)
		minstrel_calc_retransmit(mp, mi, index);

	if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) {
		ratetbl->rate[offset].count = 2;
		ratetbl->rate[offset].count_rts = 2;
		ratetbl->rate[offset].count_cts = 2;
	} else {
		ratetbl->rate[offset].count = mr->retry_count;
		ratetbl->rate[offset].count_cts = mr->retry_count;
		ratetbl->rate[offset].count_rts = mr->retry_count_rtscts;
	}

	if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
		idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
		flags = 0;
	} else {
		idx = index % MCS_GROUP_RATES +
		      (group->streams - 1) * MCS_GROUP_RATES;
		flags = IEEE80211_TX_RC_MCS | group->flags;
	}

	if (offset > 0) {
		ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
		flags |= IEEE80211_TX_RC_USE_RTS_CTS;
	}

	ratetbl->rate[offset].idx = idx;
	ratetbl->rate[offset].flags = flags;
}

static char *
minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)
{
	const struct mcs_group *mg;
	unsigned int j, tp_max, tp_avg, eprob, tx_time;
	char htmode = '2';
	char gimode = 'L';
	u32 gflags;

	if (!mi->supported[i])
		return p;

	mg = &minstrel_mcs_groups[i];
	gflags = mg->flags;

	if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
		htmode = '4';
	else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
		htmode = '8';
	if (gflags & IEEE80211_TX_RC_SHORT_GI)
		gimode = 'S';

	for (j = 0; j < MCS_GROUP_RATES; j++) {
		struct minstrel_rate_stats *mrs = &mi->groups[i].rates[j];
		static const int bitrates[4] = { 10, 20, 55, 110 };
		int idx = i * MCS_GROUP_RATES + j;
		unsigned int prob_ewmsd;

		if (!(mi->supported[i] & BIT(j)))
			continue;

		if (gflags & IEEE80211_TX_RC_MCS) {
			p += sprintf(p, "HT%c0  ", htmode);
			p += sprintf(p, "%cGI  ", gimode);
			p += sprintf(p, "%d  ", mg->streams);
		} else if (gflags & IEEE80211_TX_RC_VHT_MCS) {
			p += sprintf(p, "VHT%c0 ", htmode);
			p += sprintf(p, "%cGI ", gimode);
			p += sprintf(p, "%d  ", mg->streams);
		} else {
			p += sprintf(p, "CCK    ");
			p += sprintf(p, "%cP  ", j < 4 ? 'L' : 'S');
			p += sprintf(p, "1 ");
		}

		*(p++) = (idx == mi->max_tp_rate[0]) ? 'A' : ' ';
		*(p++) = (idx == mi->max_tp_rate[1]) ? 'B' : ' ';
		*(p++) = (idx == mi->max_tp_rate[2]) ? 'C' : ' ';
		*(p++) = (idx == mi->max_tp_rate[3]) ? 'D' : ' ';
		*(p++) = (idx == mi->max_prob_rate) ? 'P' : ' ';

		if (gflags & IEEE80211_TX_RC_MCS) {
			p += sprintf(p, "  MCS%-2u", (mg->streams - 1) * 8 + j);
		} else if (gflags & IEEE80211_TX_RC_VHT_MCS) {
			p += sprintf(p, "  MCS%-1u/%1u", j, mg->streams);
		} else {
			int r = bitrates[j % 4];

			p += sprintf(p, "   %2u.%1uM", r / 10, r % 10);
		}

		p += sprintf(p, "  %3u  ", idx);

		/* tx_time[rate(i)] in usec */
		tx_time = DIV_ROUND_CLOSEST(mg->duration[j], 1000);
		p += sprintf(p, "%6u  ", tx_time);

		tp_max = minstrel_ht_get_tp_avg(mi, i, j, MINSTREL_FRAC(100, 100));
		tp_avg = minstrel_ht_get_tp_avg(mi, i, j, mrs->prob_ewma);
		eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);
		prob_ewmsd = minstrel_get_ewmsd10(mrs);

		p += sprintf(p, "%4u.%1u    %4u.%1u     %3u.%1u    %3u.%1u"
				"     %3u   %3u %-3u   "
				"%9llu   %-9llu\n",
				tp_max / 10, tp_max % 10,
				tp_avg / 10, tp_avg % 10,
				eprob / 10, eprob % 10,
				prob_ewmsd / 10, prob_ewmsd % 10,
				mrs->retry_count,
				mrs->last_success,
				mrs->last_attempts,
				(unsigned long long)mrs->succ_hist,
				(unsigned long long)mrs->att_hist);
	}

	return p;
}

static void
minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
                      struct ieee80211_sta *sta, void *priv_sta,
                      struct ieee80211_tx_info *info)
{
	struct minstrel_ht_sta_priv *msp = priv_sta;
	struct minstrel_ht_sta *mi = &msp->ht;
	struct ieee80211_tx_rate *ar = info->status.rates;
	struct minstrel_rate_stats *rate, *rate2;
	struct minstrel_priv *mp = priv;
	bool last, update = false;
	int i;

	if (!msp->is_ht)
		return mac80211_minstrel.tx_status_noskb(priv, sband, sta,
							 &msp->legacy, info);

	/* This packet was aggregated but doesn't carry status info */
	if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
	    !(info->flags & IEEE80211_TX_STAT_AMPDU))
		return;

	if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
		info->status.ampdu_ack_len =
			(info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
		info->status.ampdu_len = 1;
	}

	mi->ampdu_packets++;
	mi->ampdu_len += info->status.ampdu_len;

	if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
		mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
		mi->sample_tries = 1;
		mi->sample_count--;
	}

	if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
		mi->sample_packets += info->status.ampdu_len;

	last = !minstrel_ht_txstat_valid(mp, &ar[0]);
	for (i = 0; !last; i++) {
		last = (i == IEEE80211_TX_MAX_RATES - 1) ||
		       !minstrel_ht_txstat_valid(mp, &ar[i + 1]);

		rate = minstrel_ht_get_stats(mp, mi, &ar[i]);

		if (last)
			rate->success += info->status.ampdu_ack_len;

		rate->attempts += ar[i].count * info->status.ampdu_len;
	}

	/*
	 * check for sudden death of spatial multiplexing,
	 * downgrade to a lower number of streams if necessary.
	 */
	rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
	if (rate->attempts > 30 &&
	    MINSTREL_FRAC(rate->success, rate->attempts) <
	    MINSTREL_FRAC(20, 100)) {
		minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
		update = true;
	}

	rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
	if (rate2->attempts > 30 &&
	    MINSTREL_FRAC(rate2->success, rate2->attempts) <
	    MINSTREL_FRAC(20, 100)) {
		minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
		update = true;
	}

	if (time_after(jiffies, mi->last_stats_update +
				(mp->update_interval / 2 * HZ) / 1000)) {
		update = true;
		minstrel_ht_update_stats(mp, mi);
	}

	if (update)
		minstrel_ht_update_rates(mp, mi);
}

/*
 * Update rate statistics and select new primary rates
 *
 * Rules for rate selection:
 *  - max_prob_rate must use only one stream, as a tradeoff between delivery
 *    probability and throughput during strong fluctuations
 *  - as long as the max prob rate has a probability of more than 75%, pick
 *    higher throughput rates, even if the probablity is a bit lower
 */
static void
minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
	struct minstrel_mcs_group_data *mg;
	struct minstrel_rate_stats *mrs;
	int group, i, j, cur_prob;
	u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
	u16 tmp_cck_tp_rate[MAX_THR_RATES], index;

	if (mi->ampdu_packets > 0) {
		mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
			MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
		mi->ampdu_len = 0;
		mi->ampdu_packets = 0;
	}

	mi->sample_slow = 0;
	mi->sample_count = 0;

	/* Initialize global rate indexes */
	for(j = 0; j < MAX_THR_RATES; j++){
		tmp_mcs_tp_rate[j] = 0;
		tmp_cck_tp_rate[j] = 0;
	}

	/* Find best rate sets within all MCS groups*/
	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {

		mg = &mi->groups[group];
		if (!mg->supported)
			continue;

		mi->sample_count++;

		/* (re)Initialize group rate indexes */
		for(j = 0; j < MAX_THR_RATES; j++)
			tmp_group_tp_rate[j] = group;

		for (i = 0; i < MCS_GROUP_RATES; i++) {
			if (!(mg->supported & BIT(i)))
				continue;

			index = MCS_GROUP_RATES * group + i;

			mrs = &mg->rates[i];
			mrs->retry_updated = false;
			minstrel_calc_rate_stats(mrs);
			cur_prob = mrs->prob_ewma;

			if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
				continue;

			/* Find max throughput rate set */
			if (group != MINSTREL_CCK_GROUP) {
				minstrel_ht_sort_best_tp_rates(mi, index,
							       tmp_mcs_tp_rate);
			} else if (group == MINSTREL_CCK_GROUP) {
				minstrel_ht_sort_best_tp_rates(mi, index,
							       tmp_cck_tp_rate);
			}

			/* Find max throughput rate set within a group */
			minstrel_ht_sort_best_tp_rates(mi, index,
						       tmp_group_tp_rate);

			/* Find max probability rate per group and global */
			minstrel_ht_set_best_prob_rate(mi, index);
		}

		memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
		       sizeof(mg->max_group_tp_rate));
	}

	/* Assign new rate set per sta */
	minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
	memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));

	/* Try to increase robustness of max_prob_rate*/
	minstrel_ht_prob_rate_reduce_streams(mi);

	/* try to sample all available rates during each interval */
	mi->sample_count *= 8;

#ifdef CONFIG_MAC80211_DEBUGFS
	/* use fixed index if set */
	if (mp->fixed_rate_idx != -1) {
		for (i = 0; i < 4; i++)
			mi->max_tp_rate[i] = mp->fixed_rate_idx;
		mi->max_prob_rate = mp->fixed_rate_idx;
	}
#endif
//.........这里部分代码省略.........

static void
minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
			struct cfg80211_chan_def *chandef,
                        struct ieee80211_sta *sta, void *priv_sta)
{
	struct minstrel_priv *mp = priv;
	struct minstrel_ht_sta_priv *msp = priv_sta;
	struct minstrel_ht_sta *mi = &msp->ht;
	struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
	u16 sta_cap = sta->ht_cap.cap;
	int n_supported = 0;
	int ack_dur;
	int stbc;
	int i;

	/* fall back to the old minstrel for legacy stations */
	if (!sta->ht_cap.ht_supported)
		goto use_legacy;

	BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
		MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);

	msp->is_ht = true;
	memset(mi, 0, sizeof(*mi));

	mi->sta = sta;
	mi->stats_update = jiffies;

	ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
	mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
	mi->overhead += ack_dur;
	mi->overhead_rtscts = mi->overhead + 2 * ack_dur;

	mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);

	/* When using MRR, sample more on the first attempt, without delay */
	if (mp->has_mrr) {
		mi->sample_count = 16;
		mi->sample_wait = 0;
	} else {
		mi->sample_count = 8;
		mi->sample_wait = 8;
	}
	mi->sample_tries = 4;

	stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
		IEEE80211_HT_CAP_RX_STBC_SHIFT;
	mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;

	if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
		mi->tx_flags |= IEEE80211_TX_CTL_LDPC;

	for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
		mi->groups[i].supported = 0;
		if (i == MINSTREL_CCK_GROUP) {
			minstrel_ht_update_cck(mp, mi, sband, sta);
			continue;
		}

		if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
			if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
				if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
					continue;
			} else {
				if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
					continue;
			}
		}

		if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
		    sta->bandwidth < IEEE80211_STA_RX_BW_40)
			continue;

		/* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
		if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
		    minstrel_mcs_groups[i].streams > 1)
			continue;

		mi->groups[i].supported =
			mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];

		if (mi->groups[i].supported)
			n_supported++;
	}

	if (!n_supported)
		goto use_legacy;

	/* create an initial rate table with the lowest supported rates */
	minstrel_ht_update_stats(mp, mi);
	minstrel_ht_update_rates(mp, mi);

	return;

use_legacy:
	msp->is_ht = false;
	memset(&msp->legacy, 0, sizeof(msp->legacy));
	msp->legacy.r = msp->ratelist;
	msp->legacy.sample_table = msp->sample_table;
	return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
//.........这里部分代码省略.........