Initial import

1 files changed, 979 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlegacy/3945-rs.c b/drivers/net/wireless/iwlegacy/3945-rs.c
new file mode 100644
index 000000000..76b0729ad
--- /dev/null
+++ b/drivers/net/wireless/iwlegacy/3945-rs.c
@@ -0,0 +1,979 @@
+/******************************************************************************
+ *
+ * Copyright(c) 2005 - 2011 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
+ *
+ * The full GNU General Public License is included in this distribution in the
+ * file called LICENSE.
+ *
+ * Contact Information:
+ *  Intel Linux Wireless <ilw@linux.intel.com>
+ * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
+ *
+ *****************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <net/mac80211.h>
+
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/delay.h>
+
+#include <linux/workqueue.h>
+
+#include "commands.h"
+#include "3945.h"
+
+#define RS_NAME "iwl-3945-rs"
+
+static s32 il3945_expected_tpt_g[RATE_COUNT_3945] = {
+	7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
+};
+
+static s32 il3945_expected_tpt_g_prot[RATE_COUNT_3945] = {
+	7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
+};
+
+static s32 il3945_expected_tpt_a[RATE_COUNT_3945] = {
+	0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186
+};
+
+static s32 il3945_expected_tpt_b[RATE_COUNT_3945] = {
+	7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+struct il3945_tpt_entry {
+	s8 min_rssi;
+	u8 idx;
+};
+
+static struct il3945_tpt_entry il3945_tpt_table_a[] = {
+	{-60, RATE_54M_IDX},
+	{-64, RATE_48M_IDX},
+	{-72, RATE_36M_IDX},
+	{-80, RATE_24M_IDX},
+	{-84, RATE_18M_IDX},
+	{-85, RATE_12M_IDX},
+	{-87, RATE_9M_IDX},
+	{-89, RATE_6M_IDX}
+};
+
+static struct il3945_tpt_entry il3945_tpt_table_g[] = {
+	{-60, RATE_54M_IDX},
+	{-64, RATE_48M_IDX},
+	{-68, RATE_36M_IDX},
+	{-80, RATE_24M_IDX},
+	{-84, RATE_18M_IDX},
+	{-85, RATE_12M_IDX},
+	{-86, RATE_11M_IDX},
+	{-88, RATE_5M_IDX},
+	{-90, RATE_2M_IDX},
+	{-92, RATE_1M_IDX}
+};
+
+#define RATE_MAX_WINDOW		62
+#define RATE_FLUSH		(3*HZ)
+#define RATE_WIN_FLUSH		(HZ/2)
+#define IL39_RATE_HIGH_TH	11520
+#define IL_SUCCESS_UP_TH	8960
+#define IL_SUCCESS_DOWN_TH	10880
+#define RATE_MIN_FAILURE_TH	6
+#define RATE_MIN_SUCCESS_TH	8
+#define RATE_DECREASE_TH	1920
+#define RATE_RETRY_TH		15
+
+static u8
+il3945_get_rate_idx_by_rssi(s32 rssi, enum ieee80211_band band)
+{
+	u32 idx = 0;
+	u32 table_size = 0;
+	struct il3945_tpt_entry *tpt_table = NULL;
+
+	if (rssi < IL_MIN_RSSI_VAL || rssi > IL_MAX_RSSI_VAL)
+		rssi = IL_MIN_RSSI_VAL;
+
+	switch (band) {
+	case IEEE80211_BAND_2GHZ:
+		tpt_table = il3945_tpt_table_g;
+		table_size = ARRAY_SIZE(il3945_tpt_table_g);
+		break;
+	case IEEE80211_BAND_5GHZ:
+		tpt_table = il3945_tpt_table_a;
+		table_size = ARRAY_SIZE(il3945_tpt_table_a);
+		break;
+	default:
+		BUG();
+		break;
+	}
+
+	while (idx < table_size && rssi < tpt_table[idx].min_rssi)
+		idx++;
+
+	idx = min(idx, table_size - 1);
+
+	return tpt_table[idx].idx;
+}
+
+static void
+il3945_clear_win(struct il3945_rate_scale_data *win)
+{
+	win->data = 0;
+	win->success_counter = 0;
+	win->success_ratio = -1;
+	win->counter = 0;
+	win->average_tpt = IL_INVALID_VALUE;
+	win->stamp = 0;
+}
+
+/**
+ * il3945_rate_scale_flush_wins - flush out the rate scale wins
+ *
+ * Returns the number of wins that have gathered data but were
+ * not flushed.  If there were any that were not flushed, then
+ * reschedule the rate flushing routine.
+ */
+static int
+il3945_rate_scale_flush_wins(struct il3945_rs_sta *rs_sta)
+{
+	int unflushed = 0;
+	int i;
+	unsigned long flags;
+	struct il_priv *il __maybe_unused = rs_sta->il;
+
+	/*
+	 * For each rate, if we have collected data on that rate
+	 * and it has been more than RATE_WIN_FLUSH
+	 * since we flushed, clear out the gathered stats
+	 */
+	for (i = 0; i < RATE_COUNT_3945; i++) {
+		if (!rs_sta->win[i].counter)
+			continue;
+
+		spin_lock_irqsave(&rs_sta->lock, flags);
+		if (time_after(jiffies, rs_sta->win[i].stamp + RATE_WIN_FLUSH)) {
+			D_RATE("flushing %d samples of rate " "idx %d\n",
+			       rs_sta->win[i].counter, i);
+			il3945_clear_win(&rs_sta->win[i]);
+		} else
+			unflushed++;
+		spin_unlock_irqrestore(&rs_sta->lock, flags);
+	}
+
+	return unflushed;
+}
+
+#define RATE_FLUSH_MAX              5000	/* msec */
+#define RATE_FLUSH_MIN              50	/* msec */
+#define IL_AVERAGE_PACKETS             1500
+
+static void
+il3945_bg_rate_scale_flush(unsigned long data)
+{
+	struct il3945_rs_sta *rs_sta = (void *)data;
+	struct il_priv *il __maybe_unused = rs_sta->il;
+	int unflushed = 0;
+	unsigned long flags;
+	u32 packet_count, duration, pps;
+
+	D_RATE("enter\n");
+
+	unflushed = il3945_rate_scale_flush_wins(rs_sta);
+
+	spin_lock_irqsave(&rs_sta->lock, flags);
+
+	/* Number of packets Rx'd since last time this timer ran */
+	packet_count = (rs_sta->tx_packets - rs_sta->last_tx_packets) + 1;
+
+	rs_sta->last_tx_packets = rs_sta->tx_packets + 1;
+
+	if (unflushed) {
+		duration =
+		    jiffies_to_msecs(jiffies - rs_sta->last_partial_flush);
+
+		D_RATE("Tx'd %d packets in %dms\n", packet_count, duration);
+
+		/* Determine packets per second */
+		if (duration)
+			pps = (packet_count * 1000) / duration;
+		else
+			pps = 0;
+
+		if (pps) {
+			duration = (IL_AVERAGE_PACKETS * 1000) / pps;
+			if (duration < RATE_FLUSH_MIN)
+				duration = RATE_FLUSH_MIN;
+			else if (duration > RATE_FLUSH_MAX)
+				duration = RATE_FLUSH_MAX;
+		} else
+			duration = RATE_FLUSH_MAX;
+
+		rs_sta->flush_time = msecs_to_jiffies(duration);
+
+		D_RATE("new flush period: %d msec ave %d\n", duration,
+		       packet_count);
+
+		mod_timer(&rs_sta->rate_scale_flush,
+			  jiffies + rs_sta->flush_time);
+
+		rs_sta->last_partial_flush = jiffies;
+	} else {
+		rs_sta->flush_time = RATE_FLUSH;
+		rs_sta->flush_pending = 0;
+	}
+	/* If there weren't any unflushed entries, we don't schedule the timer
+	 * to run again */
+
+	rs_sta->last_flush = jiffies;
+
+	spin_unlock_irqrestore(&rs_sta->lock, flags);
+
+	D_RATE("leave\n");
+}
+
+/**
+ * il3945_collect_tx_data - Update the success/failure sliding win
+ *
+ * We keep a sliding win of the last 64 packets transmitted
+ * at this rate.  win->data contains the bitmask of successful
+ * packets.
+ */
+static void
+il3945_collect_tx_data(struct il3945_rs_sta *rs_sta,
+		       struct il3945_rate_scale_data *win, int success,
+		       int retries, int idx)
+{
+	unsigned long flags;
+	s32 fail_count;
+	struct il_priv *il __maybe_unused = rs_sta->il;
+
+	if (!retries) {
+		D_RATE("leave: retries == 0 -- should be at least 1\n");
+		return;
+	}
+
+	spin_lock_irqsave(&rs_sta->lock, flags);
+
+	/*
+	 * Keep track of only the latest 62 tx frame attempts in this rate's
+	 * history win; anything older isn't really relevant any more.
+	 * If we have filled up the sliding win, drop the oldest attempt;
+	 * if the oldest attempt (highest bit in bitmap) shows "success",
+	 * subtract "1" from the success counter (this is the main reason
+	 * we keep these bitmaps!).
+	 * */
+	while (retries > 0) {
+		if (win->counter >= RATE_MAX_WINDOW) {
+
+			/* remove earliest */
+			win->counter = RATE_MAX_WINDOW - 1;
+
+			if (win->data & (1ULL << (RATE_MAX_WINDOW - 1))) {
+				win->data &= ~(1ULL << (RATE_MAX_WINDOW - 1));
+				win->success_counter--;
+			}
+		}
+
+		/* Increment frames-attempted counter */
+		win->counter++;
+
+		/* Shift bitmap by one frame (throw away oldest history),
+		 * OR in "1", and increment "success" if this
+		 * frame was successful. */
+		win->data <<= 1;
+		if (success > 0) {
+			win->success_counter++;
+			win->data |= 0x1;
+			success--;
+		}
+
+		retries--;
+	}
+
+	/* Calculate current success ratio, avoid divide-by-0! */
+	if (win->counter > 0)
+		win->success_ratio =
+		    128 * (100 * win->success_counter) / win->counter;
+	else
+		win->success_ratio = IL_INVALID_VALUE;
+
+	fail_count = win->counter - win->success_counter;
+
+	/* Calculate average throughput, if we have enough history. */
+	if (fail_count >= RATE_MIN_FAILURE_TH ||
+	    win->success_counter >= RATE_MIN_SUCCESS_TH)
+		win->average_tpt =
+		    ((win->success_ratio * rs_sta->expected_tpt[idx] +
+		      64) / 128);
+	else
+		win->average_tpt = IL_INVALID_VALUE;
+
+	/* Tag this win as having been updated */
+	win->stamp = jiffies;
+
+	spin_unlock_irqrestore(&rs_sta->lock, flags);
+}
+
+/*
+ * Called after adding a new station to initialize rate scaling
+ */
+void
+il3945_rs_rate_init(struct il_priv *il, struct ieee80211_sta *sta, u8 sta_id)
+{
+	struct ieee80211_hw *hw = il->hw;
+	struct ieee80211_conf *conf = &il->hw->conf;
+	struct il3945_sta_priv *psta;
+	struct il3945_rs_sta *rs_sta;
+	struct ieee80211_supported_band *sband;
+	int i;
+
+	D_INFO("enter\n");
+	if (sta_id == il->hw_params.bcast_id)
+		goto out;
+
+	psta = (struct il3945_sta_priv *)sta->drv_priv;
+	rs_sta = &psta->rs_sta;
+	sband = hw->wiphy->bands[conf->chandef.chan->band];
+
+	rs_sta->il = il;
+
+	rs_sta->start_rate = RATE_INVALID;
+
+	/* default to just 802.11b */
+	rs_sta->expected_tpt = il3945_expected_tpt_b;
+
+	rs_sta->last_partial_flush = jiffies;
+	rs_sta->last_flush = jiffies;
+	rs_sta->flush_time = RATE_FLUSH;
+	rs_sta->last_tx_packets = 0;
+
+	rs_sta->rate_scale_flush.data = (unsigned long)rs_sta;
+	rs_sta->rate_scale_flush.function = il3945_bg_rate_scale_flush;
+
+	for (i = 0; i < RATE_COUNT_3945; i++)
+		il3945_clear_win(&rs_sta->win[i]);
+
+	/* TODO: what is a good starting rate for STA? About middle? Maybe not
+	 * the lowest or the highest rate.. Could consider using RSSI from
+	 * previous packets? Need to have IEEE 802.1X auth succeed immediately
+	 * after assoc.. */
+
+	for (i = sband->n_bitrates - 1; i >= 0; i--) {
+		if (sta->supp_rates[sband->band] & (1 << i)) {
+			rs_sta->last_txrate_idx = i;
+			break;
+		}
+	}
+
+	il->_3945.sta_supp_rates = sta->supp_rates[sband->band];
+	/* For 5 GHz band it start at IL_FIRST_OFDM_RATE */
+	if (sband->band == IEEE80211_BAND_5GHZ) {
+		rs_sta->last_txrate_idx += IL_FIRST_OFDM_RATE;
+		il->_3945.sta_supp_rates <<= IL_FIRST_OFDM_RATE;
+	}
+
+out:
+	il->stations[sta_id].used &= ~IL_STA_UCODE_INPROGRESS;
+
+	D_INFO("leave\n");
+}
+
+static void *
+il3945_rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+{
+	return hw->priv;
+}
+
+/* rate scale requires free function to be implemented */
+static void
+il3945_rs_free(void *il)
+{
+}
+
+static void *
+il3945_rs_alloc_sta(void *il_priv, struct ieee80211_sta *sta, gfp_t gfp)
+{
+	struct il3945_rs_sta *rs_sta;
+	struct il3945_sta_priv *psta = (void *)sta->drv_priv;
+	struct il_priv *il __maybe_unused = il_priv;
+
+	D_RATE("enter\n");
+
+	rs_sta = &psta->rs_sta;
+
+	spin_lock_init(&rs_sta->lock);
+	init_timer(&rs_sta->rate_scale_flush);
+
+	D_RATE("leave\n");
+
+	return rs_sta;
+}
+
+static void
+il3945_rs_free_sta(void *il_priv, struct ieee80211_sta *sta, void *il_sta)
+{
+	struct il3945_rs_sta *rs_sta = il_sta;
+
+	/*
+	 * Be careful not to use any members of il3945_rs_sta (like trying
+	 * to use il_priv to print out debugging) since it may not be fully
+	 * initialized at this point.
+	 */
+	del_timer_sync(&rs_sta->rate_scale_flush);
+}
+
+/**
+ * il3945_rs_tx_status - Update rate control values based on Tx results
+ *
+ * NOTE: Uses il_priv->retry_rate for the # of retries attempted by
+ * the hardware for each rate.
+ */
+static void
+il3945_rs_tx_status(void *il_rate, struct ieee80211_supported_band *sband,
+		    struct ieee80211_sta *sta, void *il_sta,
+		    struct sk_buff *skb)
+{
+	s8 retries = 0, current_count;
+	int scale_rate_idx, first_idx, last_idx;
+	unsigned long flags;
+	struct il_priv *il = (struct il_priv *)il_rate;
+	struct il3945_rs_sta *rs_sta = il_sta;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
+	D_RATE("enter\n");
+
+	retries = info->status.rates[0].count;
+	/* Sanity Check for retries */
+	if (retries > RATE_RETRY_TH)
+		retries = RATE_RETRY_TH;
+
+	first_idx = sband->bitrates[info->status.rates[0].idx].hw_value;
+	if (first_idx < 0 || first_idx >= RATE_COUNT_3945) {
+		D_RATE("leave: Rate out of bounds: %d\n", first_idx);
+		return;
+	}
+
+	if (!il_sta) {
+		D_RATE("leave: No STA il data to update!\n");
+		return;
+	}
+
+	/* Treat uninitialized rate scaling data same as non-existing. */
+	if (!rs_sta->il) {
+		D_RATE("leave: STA il data uninitialized!\n");
+		return;
+	}
+
+	rs_sta->tx_packets++;
+
+	scale_rate_idx = first_idx;
+	last_idx = first_idx;
+
+	/*
+	 * Update the win for each rate.  We determine which rates
+	 * were Tx'd based on the total number of retries vs. the number
+	 * of retries configured for each rate -- currently set to the
+	 * il value 'retry_rate' vs. rate specific
+	 *
+	 * On exit from this while loop last_idx indicates the rate
+	 * at which the frame was finally transmitted (or failed if no
+	 * ACK)
+	 */
+	while (retries > 1) {
+		if ((retries - 1) < il->retry_rate) {
+			current_count = (retries - 1);
+			last_idx = scale_rate_idx;
+		} else {
+			current_count = il->retry_rate;
+			last_idx = il3945_rs_next_rate(il, scale_rate_idx);
+		}
+
+		/* Update this rate accounting for as many retries
+		 * as was used for it (per current_count) */
+		il3945_collect_tx_data(rs_sta, &rs_sta->win[scale_rate_idx], 0,
+				       current_count, scale_rate_idx);
+		D_RATE("Update rate %d for %d retries.\n", scale_rate_idx,
+		       current_count);
+
+		retries -= current_count;
+
+		scale_rate_idx = last_idx;
+	}
+
+	/* Update the last idx win with success/failure based on ACK */
+	D_RATE("Update rate %d with %s.\n", last_idx,
+	       (info->flags & IEEE80211_TX_STAT_ACK) ? "success" : "failure");
+	il3945_collect_tx_data(rs_sta, &rs_sta->win[last_idx],
+			       info->flags & IEEE80211_TX_STAT_ACK, 1,
+			       last_idx);
+
+	/* We updated the rate scale win -- if its been more than
+	 * flush_time since the last run, schedule the flush
+	 * again */
+	spin_lock_irqsave(&rs_sta->lock, flags);
+
+	if (!rs_sta->flush_pending &&
+	    time_after(jiffies, rs_sta->last_flush + rs_sta->flush_time)) {
+
+		rs_sta->last_partial_flush = jiffies;
+		rs_sta->flush_pending = 1;
+		mod_timer(&rs_sta->rate_scale_flush,
+			  jiffies + rs_sta->flush_time);
+	}
+
+	spin_unlock_irqrestore(&rs_sta->lock, flags);
+
+	D_RATE("leave\n");
+}
+
+static u16
+il3945_get_adjacent_rate(struct il3945_rs_sta *rs_sta, u8 idx, u16 rate_mask,
+			 enum ieee80211_band band)
+{
+	u8 high = RATE_INVALID;
+	u8 low = RATE_INVALID;
+	struct il_priv *il __maybe_unused = rs_sta->il;
+
+	/* 802.11A walks to the next literal adjacent rate in
+	 * the rate table */
+	if (unlikely(band == IEEE80211_BAND_5GHZ)) {
+		int i;
+		u32 mask;
+
+		/* Find the previous rate that is in the rate mask */
+		i = idx - 1;
+		for (mask = (1 << i); i >= 0; i--, mask >>= 1) {
+			if (rate_mask & mask) {
+				low = i;
+				break;
+			}
+		}
+
+		/* Find the next rate that is in the rate mask */
+		i = idx + 1;
+		for (mask = (1 << i); i < RATE_COUNT_3945; i++, mask <<= 1) {
+			if (rate_mask & mask) {
+				high = i;
+				break;
+			}
+		}
+
+		return (high << 8) | low;
+	}
+
+	low = idx;
+	while (low != RATE_INVALID) {
+		if (rs_sta->tgg)
+			low = il3945_rates[low].prev_rs_tgg;
+		else
+			low = il3945_rates[low].prev_rs;
+		if (low == RATE_INVALID)
+			break;
+		if (rate_mask & (1 << low))
+			break;
+		D_RATE("Skipping masked lower rate: %d\n", low);
+	}
+
+	high = idx;
+	while (high != RATE_INVALID) {
+		if (rs_sta->tgg)
+			high = il3945_rates[high].next_rs_tgg;
+		else
+			high = il3945_rates[high].next_rs;
+		if (high == RATE_INVALID)
+			break;
+		if (rate_mask & (1 << high))
+			break;
+		D_RATE("Skipping masked higher rate: %d\n", high);
+	}
+
+	return (high << 8) | low;
+}
+
+/**
+ * il3945_rs_get_rate - find the rate for the requested packet
+ *
+ * Returns the ieee80211_rate structure allocated by the driver.
+ *
+ * The rate control algorithm has no internal mapping between hw_mode's
+ * rate ordering and the rate ordering used by the rate control algorithm.
+ *
+ * The rate control algorithm uses a single table of rates that goes across
+ * the entire A/B/G spectrum vs. being limited to just one particular
+ * hw_mode.
+ *
+ * As such, we can't convert the idx obtained below into the hw_mode's
+ * rate table and must reference the driver allocated rate table
+ *
+ */
+static void
+il3945_rs_get_rate(void *il_r, struct ieee80211_sta *sta, void *il_sta,
+		   struct ieee80211_tx_rate_control *txrc)
+{
+	struct ieee80211_supported_band *sband = txrc->sband;
+	struct sk_buff *skb = txrc->skb;
+	u8 low = RATE_INVALID;
+	u8 high = RATE_INVALID;
+	u16 high_low;
+	int idx;
+	struct il3945_rs_sta *rs_sta = il_sta;
+	struct il3945_rate_scale_data *win = NULL;
+	int current_tpt = IL_INVALID_VALUE;
+	int low_tpt = IL_INVALID_VALUE;
+	int high_tpt = IL_INVALID_VALUE;
+	u32 fail_count;
+	s8 scale_action = 0;
+	unsigned long flags;
+	u16 rate_mask;
+	s8 max_rate_idx = -1;
+	struct il_priv *il __maybe_unused = (struct il_priv *)il_r;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
+	D_RATE("enter\n");
+
+	/* Treat uninitialized rate scaling data same as non-existing. */
+	if (rs_sta && !rs_sta->il) {
+		D_RATE("Rate scaling information not initialized yet.\n");
+		il_sta = NULL;
+	}
+
+	if (rate_control_send_low(sta, il_sta, txrc))
+		return;
+
+	rate_mask = sta->supp_rates[sband->band];
+
+	/* get user max rate if set */
+	max_rate_idx = txrc->max_rate_idx;
+	if (sband->band == IEEE80211_BAND_5GHZ && max_rate_idx != -1)
+		max_rate_idx += IL_FIRST_OFDM_RATE;
+	if (max_rate_idx < 0 || max_rate_idx >= RATE_COUNT)
+		max_rate_idx = -1;
+
+	idx = min(rs_sta->last_txrate_idx & 0xffff, RATE_COUNT_3945 - 1);
+
+	if (sband->band == IEEE80211_BAND_5GHZ)
+		rate_mask = rate_mask << IL_FIRST_OFDM_RATE;
+
+	spin_lock_irqsave(&rs_sta->lock, flags);
+
+	/* for recent assoc, choose best rate regarding
+	 * to rssi value
+	 */
+	if (rs_sta->start_rate != RATE_INVALID) {
+		if (rs_sta->start_rate < idx &&
+		    (rate_mask & (1 << rs_sta->start_rate)))
+			idx = rs_sta->start_rate;
+		rs_sta->start_rate = RATE_INVALID;
+	}
+
+	/* force user max rate if set by user */
+	if (max_rate_idx != -1 && max_rate_idx < idx) {
+		if (rate_mask & (1 << max_rate_idx))
+			idx = max_rate_idx;
+	}
+
+	win = &(rs_sta->win[idx]);
+
+	fail_count = win->counter - win->success_counter;
+
+	if (fail_count < RATE_MIN_FAILURE_TH &&
+	    win->success_counter < RATE_MIN_SUCCESS_TH) {
+		spin_unlock_irqrestore(&rs_sta->lock, flags);
+
+		D_RATE("Invalid average_tpt on rate %d: "
+		       "counter: %d, success_counter: %d, "
+		       "expected_tpt is %sNULL\n", idx, win->counter,
+		       win->success_counter,
+		       rs_sta->expected_tpt ? "not " : "");
+
+		/* Can't calculate this yet; not enough history */
+		win->average_tpt = IL_INVALID_VALUE;
+		goto out;
+
+	}
+
+	current_tpt = win->average_tpt;
+
+	high_low =
+	    il3945_get_adjacent_rate(rs_sta, idx, rate_mask, sband->band);
+	low = high_low & 0xff;
+	high = (high_low >> 8) & 0xff;
+
+	/* If user set max rate, dont allow higher than user constrain */
+	if (max_rate_idx != -1 && max_rate_idx < high)
+		high = RATE_INVALID;
+
+	/* Collect Measured throughputs of adjacent rates */
+	if (low != RATE_INVALID)
+		low_tpt = rs_sta->win[low].average_tpt;
+
+	if (high != RATE_INVALID)
+		high_tpt = rs_sta->win[high].average_tpt;
+
+	spin_unlock_irqrestore(&rs_sta->lock, flags);
+
+	scale_action = 0;
+
+	/* Low success ratio , need to drop the rate */
+	if (win->success_ratio < RATE_DECREASE_TH || !current_tpt) {
+		D_RATE("decrease rate because of low success_ratio\n");
+		scale_action = -1;
+		/* No throughput measured yet for adjacent rates,
+		 * try increase */
+	} else if (low_tpt == IL_INVALID_VALUE && high_tpt == IL_INVALID_VALUE) {
+
+		if (high != RATE_INVALID &&
+		    win->success_ratio >= RATE_INCREASE_TH)
+			scale_action = 1;
+		else if (low != RATE_INVALID)
+			scale_action = 0;
+
+		/* Both adjacent throughputs are measured, but neither one has
+		 * better throughput; we're using the best rate, don't change
+		 * it! */
+	} else if (low_tpt != IL_INVALID_VALUE && high_tpt != IL_INVALID_VALUE
+		   && low_tpt < current_tpt && high_tpt < current_tpt) {
+
+		D_RATE("No action -- low [%d] & high [%d] < "
+		       "current_tpt [%d]\n", low_tpt, high_tpt, current_tpt);
+		scale_action = 0;
+
+		/* At least one of the rates has better throughput */
+	} else {
+		if (high_tpt != IL_INVALID_VALUE) {
+
+			/* High rate has better throughput, Increase
+			 * rate */
+			if (high_tpt > current_tpt &&
+			    win->success_ratio >= RATE_INCREASE_TH)
+				scale_action = 1;
+			else {
+				D_RATE("decrease rate because of high tpt\n");
+				scale_action = 0;
+			}
+		} else if (low_tpt != IL_INVALID_VALUE) {
+			if (low_tpt > current_tpt) {
+				D_RATE("decrease rate because of low tpt\n");
+				scale_action = -1;
+			} else if (win->success_ratio >= RATE_INCREASE_TH) {
+				/* Lower rate has better
+				 * throughput,decrease rate */
+				scale_action = 1;
+			}
+		}
+	}
+
+	/* Sanity check; asked for decrease, but success rate or throughput
+	 * has been good at old rate.  Don't change it. */
+	if (scale_action == -1 && low != RATE_INVALID &&
+	    (win->success_ratio > RATE_HIGH_TH ||
+	     current_tpt > 100 * rs_sta->expected_tpt[low]))
+		scale_action = 0;
+
+	switch (scale_action) {
+	case -1:
+		/* Decrese rate */
+		if (low != RATE_INVALID)
+			idx = low;
+		break;
+	case 1:
+		/* Increase rate */
+		if (high != RATE_INVALID)
+			idx = high;
+
+		break;
+	case 0:
+	default:
+		/* No change */
+		break;
+	}
+
+	D_RATE("Selected %d (action %d) - low %d high %d\n", idx, scale_action,
+	       low, high);
+
+out:
+
+	if (sband->band == IEEE80211_BAND_5GHZ) {
+		if (WARN_ON_ONCE(idx < IL_FIRST_OFDM_RATE))
+			idx = IL_FIRST_OFDM_RATE;
+		rs_sta->last_txrate_idx = idx;
+		info->control.rates[0].idx = idx - IL_FIRST_OFDM_RATE;
+	} else {
+		rs_sta->last_txrate_idx = idx;
+		info->control.rates[0].idx = rs_sta->last_txrate_idx;
+	}
+	info->control.rates[0].count = 1;
+
+	D_RATE("leave: %d\n", idx);
+}
+
+#ifdef CONFIG_MAC80211_DEBUGFS
+
+static ssize_t
+il3945_sta_dbgfs_stats_table_read(struct file *file, char __user *user_buf,
+				  size_t count, loff_t *ppos)
+{
+	char *buff;
+	int desc = 0;
+	int j;
+	ssize_t ret;
+	struct il3945_rs_sta *lq_sta = file->private_data;
+
+	buff = kmalloc(1024, GFP_KERNEL);
+	if (!buff)
+		return -ENOMEM;
+
+	desc +=
+	    sprintf(buff + desc,
+		    "tx packets=%d last rate idx=%d\n"
+		    "rate=0x%X flush time %d\n", lq_sta->tx_packets,
+		    lq_sta->last_txrate_idx, lq_sta->start_rate,
+		    jiffies_to_msecs(lq_sta->flush_time));
+	for (j = 0; j < RATE_COUNT_3945; j++) {
+		desc +=
+		    sprintf(buff + desc, "counter=%d success=%d %%=%d\n",
+			    lq_sta->win[j].counter,
+			    lq_sta->win[j].success_counter,
+			    lq_sta->win[j].success_ratio);
+	}
+	ret = simple_read_from_buffer(user_buf, count, ppos, buff, desc);
+	kfree(buff);
+	return ret;
+}
+
+static const struct file_operations rs_sta_dbgfs_stats_table_ops = {
+	.read = il3945_sta_dbgfs_stats_table_read,
+	.open = simple_open,
+	.llseek = default_llseek,
+};
+
+static void
+il3945_add_debugfs(void *il, void *il_sta, struct dentry *dir)
+{
+	struct il3945_rs_sta *lq_sta = il_sta;
+
+	lq_sta->rs_sta_dbgfs_stats_table_file =
+	    debugfs_create_file("rate_stats_table", 0600, dir, lq_sta,
+				&rs_sta_dbgfs_stats_table_ops);
+
+}
+
+static void
+il3945_remove_debugfs(void *il, void *il_sta)
+{
+	struct il3945_rs_sta *lq_sta = il_sta;
+	debugfs_remove(lq_sta->rs_sta_dbgfs_stats_table_file);
+}
+#endif
+
+/*
+ * Initialization of rate scaling information is done by driver after
+ * the station is added. Since mac80211 calls this function before a
+ * station is added we ignore it.
+ */
+static void
+il3945_rs_rate_init_stub(void *il_r, struct ieee80211_supported_band *sband,
+			 struct cfg80211_chan_def *chandef,
+			 struct ieee80211_sta *sta, void *il_sta)
+{
+}
+
+static const struct rate_control_ops rs_ops = {
+	.name = RS_NAME,
+	.tx_status = il3945_rs_tx_status,
+	.get_rate = il3945_rs_get_rate,
+	.rate_init = il3945_rs_rate_init_stub,
+	.alloc = il3945_rs_alloc,
+	.free = il3945_rs_free,
+	.alloc_sta = il3945_rs_alloc_sta,
+	.free_sta = il3945_rs_free_sta,
+#ifdef CONFIG_MAC80211_DEBUGFS
+	.add_sta_debugfs = il3945_add_debugfs,
+	.remove_sta_debugfs = il3945_remove_debugfs,
+#endif
+
+};
+
+void
+il3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
+{
+	struct il_priv *il = hw->priv;
+	s32 rssi = 0;
+	unsigned long flags;
+	struct il3945_rs_sta *rs_sta;
+	struct ieee80211_sta *sta;
+	struct il3945_sta_priv *psta;
+
+	D_RATE("enter\n");
+
+	rcu_read_lock();
+
+	sta = ieee80211_find_sta(il->vif, il->stations[sta_id].sta.sta.addr);
+	if (!sta) {
+		D_RATE("Unable to find station to initialize rate scaling.\n");
+		rcu_read_unlock();
+		return;
+	}
+
+	psta = (void *)sta->drv_priv;
+	rs_sta = &psta->rs_sta;
+
+	spin_lock_irqsave(&rs_sta->lock, flags);
+
+	rs_sta->tgg = 0;
+	switch (il->band) {
+	case IEEE80211_BAND_2GHZ:
+		/* TODO: this always does G, not a regression */
+		if (il->active.flags & RXON_FLG_TGG_PROTECT_MSK) {
+			rs_sta->tgg = 1;
+			rs_sta->expected_tpt = il3945_expected_tpt_g_prot;
+		} else
+			rs_sta->expected_tpt = il3945_expected_tpt_g;
+		break;
+	case IEEE80211_BAND_5GHZ:
+		rs_sta->expected_tpt = il3945_expected_tpt_a;
+		break;
+	default:
+		BUG();
+		break;
+	}
+
+	spin_unlock_irqrestore(&rs_sta->lock, flags);
+
+	rssi = il->_3945.last_rx_rssi;
+	if (rssi == 0)
+		rssi = IL_MIN_RSSI_VAL;
+
+	D_RATE("Network RSSI: %d\n", rssi);
+
+	rs_sta->start_rate = il3945_get_rate_idx_by_rssi(rssi, il->band);
+
+	D_RATE("leave: rssi %d assign rate idx: " "%d (plcp 0x%x)\n", rssi,
+	       rs_sta->start_rate, il3945_rates[rs_sta->start_rate].plcp);
+	rcu_read_unlock();
+}
+
+int
+il3945_rate_control_register(void)
+{
+	return ieee80211_rate_control_register(&rs_ops);
+}
+
+void
+il3945_rate_control_unregister(void)
+{
+	ieee80211_rate_control_unregister(&rs_ops);
+}