Revert "iwlwifi: split the drivers for agn and legacy devices 3945/4965"

This reverts commit aa833c4b1a928b8d3c4fcc2faaa0d6b81ea02b56.

1 files changed, 995 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-3945-rs.c b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
new file mode 100644
index 000000000000..1f3e7e34fbc7
--- /dev/null
+++ b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
@@ -0,0 +1,995 @@
+/******************************************************************************
+ *
+ * Copyright(c) 2005 - 2010 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/init.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/wireless.h>
+#include <net/mac80211.h>
+
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/delay.h>
+
+#include <linux/workqueue.h>
+
+#include "iwl-commands.h"
+#include "iwl-3945.h"
+#include "iwl-sta.h"
+
+#define RS_NAME "iwl-3945-rs"
+
+static s32 iwl3945_expected_tpt_g[IWL_RATE_COUNT_3945] = {
+	7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
+};
+
+static s32 iwl3945_expected_tpt_g_prot[IWL_RATE_COUNT_3945] = {
+	7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
+};
+
+static s32 iwl3945_expected_tpt_a[IWL_RATE_COUNT_3945] = {
+	0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186
+};
+
+static s32 iwl3945_expected_tpt_b[IWL_RATE_COUNT_3945] = {
+	7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+struct iwl3945_tpt_entry {
+	s8 min_rssi;
+	u8 index;
+};
+
+static struct iwl3945_tpt_entry iwl3945_tpt_table_a[] = {
+	{-60, IWL_RATE_54M_INDEX},
+	{-64, IWL_RATE_48M_INDEX},
+	{-72, IWL_RATE_36M_INDEX},
+	{-80, IWL_RATE_24M_INDEX},
+	{-84, IWL_RATE_18M_INDEX},
+	{-85, IWL_RATE_12M_INDEX},
+	{-87, IWL_RATE_9M_INDEX},
+	{-89, IWL_RATE_6M_INDEX}
+};
+
+static struct iwl3945_tpt_entry iwl3945_tpt_table_g[] = {
+	{-60, IWL_RATE_54M_INDEX},
+	{-64, IWL_RATE_48M_INDEX},
+	{-68, IWL_RATE_36M_INDEX},
+	{-80, IWL_RATE_24M_INDEX},
+	{-84, IWL_RATE_18M_INDEX},
+	{-85, IWL_RATE_12M_INDEX},
+	{-86, IWL_RATE_11M_INDEX},
+	{-88, IWL_RATE_5M_INDEX},
+	{-90, IWL_RATE_2M_INDEX},
+	{-92, IWL_RATE_1M_INDEX}
+};
+
+#define IWL_RATE_MAX_WINDOW          62
+#define IWL_RATE_FLUSH       	 (3*HZ)
+#define IWL_RATE_WIN_FLUSH       (HZ/2)
+#define IWL39_RATE_HIGH_TH          11520
+#define IWL_SUCCESS_UP_TH	   8960
+#define IWL_SUCCESS_DOWN_TH	  10880
+#define IWL_RATE_MIN_FAILURE_TH       6
+#define IWL_RATE_MIN_SUCCESS_TH       8
+#define IWL_RATE_DECREASE_TH       1920
+#define IWL_RATE_RETRY_TH	     15
+
+static u8 iwl3945_get_rate_index_by_rssi(s32 rssi, enum ieee80211_band band)
+{
+	u32 index = 0;
+	u32 table_size = 0;
+	struct iwl3945_tpt_entry *tpt_table = NULL;
+
+	if ((rssi < IWL_MIN_RSSI_VAL) || (rssi > IWL_MAX_RSSI_VAL))
+		rssi = IWL_MIN_RSSI_VAL;
+
+	switch (band) {
+	case IEEE80211_BAND_2GHZ:
+		tpt_table = iwl3945_tpt_table_g;
+		table_size = ARRAY_SIZE(iwl3945_tpt_table_g);
+		break;
+
+	case IEEE80211_BAND_5GHZ:
+		tpt_table = iwl3945_tpt_table_a;
+		table_size = ARRAY_SIZE(iwl3945_tpt_table_a);
+		break;
+
+	default:
+		BUG();
+		break;
+	}
+
+	while ((index < table_size) && (rssi < tpt_table[index].min_rssi))
+		index++;
+
+	index = min(index, (table_size - 1));
+
+	return tpt_table[index].index;
+}
+
+static void iwl3945_clear_window(struct iwl3945_rate_scale_data *window)
+{
+	window->data = 0;
+	window->success_counter = 0;
+	window->success_ratio = -1;
+	window->counter = 0;
+	window->average_tpt = IWL_INVALID_VALUE;
+	window->stamp = 0;
+}
+
+/**
+ * iwl3945_rate_scale_flush_windows - flush out the rate scale windows
+ *
+ * Returns the number of windows that have gathered data but were
+ * not flushed.  If there were any that were not flushed, then
+ * reschedule the rate flushing routine.
+ */
+static int iwl3945_rate_scale_flush_windows(struct iwl3945_rs_sta *rs_sta)
+{
+	int unflushed = 0;
+	int i;
+	unsigned long flags;
+	struct iwl_priv *priv __maybe_unused = rs_sta->priv;
+
+	/*
+	 * For each rate, if we have collected data on that rate
+	 * and it has been more than IWL_RATE_WIN_FLUSH
+	 * since we flushed, clear out the gathered statistics
+	 */
+	for (i = 0; i < IWL_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 +
+			       IWL_RATE_WIN_FLUSH)) {
+			IWL_DEBUG_RATE(priv, "flushing %d samples of rate "
+				       "index %d\n",
+				       rs_sta->win[i].counter, i);
+			iwl3945_clear_window(&rs_sta->win[i]);
+		} else
+			unflushed++;
+		spin_unlock_irqrestore(&rs_sta->lock, flags);
+	}
+
+	return unflushed;
+}
+
+#define IWL_RATE_FLUSH_MAX              5000	/* msec */
+#define IWL_RATE_FLUSH_MIN              50	/* msec */
+#define IWL_AVERAGE_PACKETS             1500
+
+static void iwl3945_bg_rate_scale_flush(unsigned long data)
+{
+	struct iwl3945_rs_sta *rs_sta = (void *)data;
+	struct iwl_priv *priv __maybe_unused = rs_sta->priv;
+	int unflushed = 0;
+	unsigned long flags;
+	u32 packet_count, duration, pps;
+
+	IWL_DEBUG_RATE(priv, "enter\n");
+
+	unflushed = iwl3945_rate_scale_flush_windows(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);
+
+		IWL_DEBUG_RATE(priv, "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 = (IWL_AVERAGE_PACKETS * 1000) / pps;
+			if (duration < IWL_RATE_FLUSH_MIN)
+				duration = IWL_RATE_FLUSH_MIN;
+			else if (duration > IWL_RATE_FLUSH_MAX)
+				duration = IWL_RATE_FLUSH_MAX;
+		} else
+			duration = IWL_RATE_FLUSH_MAX;
+
+		rs_sta->flush_time = msecs_to_jiffies(duration);
+
+		IWL_DEBUG_RATE(priv, "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 = IWL_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);
+
+	IWL_DEBUG_RATE(priv, "leave\n");
+}
+
+/**
+ * iwl3945_collect_tx_data - Update the success/failure sliding window
+ *
+ * We keep a sliding window of the last 64 packets transmitted
+ * at this rate.  window->data contains the bitmask of successful
+ * packets.
+ */
+static void iwl3945_collect_tx_data(struct iwl3945_rs_sta *rs_sta,
+				struct iwl3945_rate_scale_data *window,
+				int success, int retries, int index)
+{
+	unsigned long flags;
+	s32 fail_count;
+	struct iwl_priv *priv __maybe_unused = rs_sta->priv;
+
+	if (!retries) {
+		IWL_DEBUG_RATE(priv, "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 window; anything older isn't really relevant any more.
+	 * If we have filled up the sliding window, 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 (window->counter >= IWL_RATE_MAX_WINDOW) {
+
+			/* remove earliest */
+			window->counter = IWL_RATE_MAX_WINDOW - 1;
+
+			if (window->data & (1ULL << (IWL_RATE_MAX_WINDOW - 1))) {
+				window->data &= ~(1ULL << (IWL_RATE_MAX_WINDOW - 1));
+				window->success_counter--;
+			}
+		}
+
+		/* Increment frames-attempted counter */
+		window->counter++;
+
+		/* Shift bitmap by one frame (throw away oldest history),
+		 * OR in "1", and increment "success" if this
+		 * frame was successful. */
+		window->data <<= 1;
+		if (success > 0) {
+			window->success_counter++;
+			window->data |= 0x1;
+			success--;
+		}
+
+		retries--;
+	}
+
+	/* Calculate current success ratio, avoid divide-by-0! */
+	if (window->counter > 0)
+		window->success_ratio = 128 * (100 * window->success_counter)
+					/ window->counter;
+	else
+		window->success_ratio = IWL_INVALID_VALUE;
+
+	fail_count = window->counter - window->success_counter;
+
+	/* Calculate average throughput, if we have enough history. */
+	if ((fail_count >= IWL_RATE_MIN_FAILURE_TH) ||
+	    (window->success_counter >= IWL_RATE_MIN_SUCCESS_TH))
+		window->average_tpt = ((window->success_ratio *
+				rs_sta->expected_tpt[index] + 64) / 128);
+	else
+		window->average_tpt = IWL_INVALID_VALUE;
+
+	/* Tag this window as having been updated */
+	window->stamp = jiffies;
+
+	spin_unlock_irqrestore(&rs_sta->lock, flags);
+
+}
+
+/*
+ * Called after adding a new station to initialize rate scaling
+ */
+void iwl3945_rs_rate_init(struct iwl_priv *priv, struct ieee80211_sta *sta, u8 sta_id)
+{
+	struct ieee80211_hw *hw = priv->hw;
+	struct ieee80211_conf *conf = &priv->hw->conf;
+	struct iwl3945_sta_priv *psta;
+	struct iwl3945_rs_sta *rs_sta;
+	struct ieee80211_supported_band *sband;
+	int i;
+
+	IWL_DEBUG_INFO(priv, "enter\n");
+	if (sta_id == priv->contexts[IWL_RXON_CTX_BSS].bcast_sta_id)
+		goto out;
+
+	psta = (struct iwl3945_sta_priv *) sta->drv_priv;
+	rs_sta = &psta->rs_sta;
+	sband = hw->wiphy->bands[conf->channel->band];
+
+	rs_sta->priv = priv;
+
+	rs_sta->start_rate = IWL_RATE_INVALID;
+
+	/* default to just 802.11b */
+	rs_sta->expected_tpt = iwl3945_expected_tpt_b;
+
+	rs_sta->last_partial_flush = jiffies;
+	rs_sta->last_flush = jiffies;
+	rs_sta->flush_time = IWL_RATE_FLUSH;
+	rs_sta->last_tx_packets = 0;
+
+	rs_sta->rate_scale_flush.data = (unsigned long)rs_sta;
+	rs_sta->rate_scale_flush.function = iwl3945_bg_rate_scale_flush;
+
+	for (i = 0; i < IWL_RATE_COUNT_3945; i++)
+		iwl3945_clear_window(&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;
+		}
+	}
+
+	priv->_3945.sta_supp_rates = sta->supp_rates[sband->band];
+	/* For 5 GHz band it start at IWL_FIRST_OFDM_RATE */
+	if (sband->band == IEEE80211_BAND_5GHZ) {
+		rs_sta->last_txrate_idx += IWL_FIRST_OFDM_RATE;
+		priv->_3945.sta_supp_rates = priv->_3945.sta_supp_rates <<
+						IWL_FIRST_OFDM_RATE;
+	}
+
+out:
+	priv->stations[sta_id].used &= ~IWL_STA_UCODE_INPROGRESS;
+
+	IWL_DEBUG_INFO(priv, "leave\n");
+}
+
+static void *rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+{
+	return hw->priv;
+}
+
+/* rate scale requires free function to be implemented */
+static void rs_free(void *priv)
+{
+	return;
+}
+
+static void *rs_alloc_sta(void *iwl_priv, struct ieee80211_sta *sta, gfp_t gfp)
+{
+	struct iwl3945_rs_sta *rs_sta;
+	struct iwl3945_sta_priv *psta = (void *) sta->drv_priv;
+	struct iwl_priv *priv __maybe_unused = iwl_priv;
+
+	IWL_DEBUG_RATE(priv, "enter\n");
+
+	rs_sta = &psta->rs_sta;
+
+	spin_lock_init(&rs_sta->lock);
+	init_timer(&rs_sta->rate_scale_flush);
+
+	IWL_DEBUG_RATE(priv, "leave\n");
+
+	return rs_sta;
+}
+
+static void rs_free_sta(void *iwl_priv, struct ieee80211_sta *sta,
+			void *priv_sta)
+{
+	struct iwl3945_rs_sta *rs_sta = priv_sta;
+
+	/*
+	 * Be careful not to use any members of iwl3945_rs_sta (like trying
+	 * to use iwl_priv to print out debugging) since it may not be fully
+	 * initialized at this point.
+	 */
+	del_timer_sync(&rs_sta->rate_scale_flush);
+}
+
+
+/**
+ * rs_tx_status - Update rate control values based on Tx results
+ *
+ * NOTE: Uses iwl_priv->retry_rate for the # of retries attempted by
+ * the hardware for each rate.
+ */
+static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband,
+			 struct ieee80211_sta *sta, void *priv_sta,
+			 struct sk_buff *skb)
+{
+	s8 retries = 0, current_count;
+	int scale_rate_index, first_index, last_index;
+	unsigned long flags;
+	struct iwl_priv *priv = (struct iwl_priv *)priv_rate;
+	struct iwl3945_rs_sta *rs_sta = priv_sta;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
+	IWL_DEBUG_RATE(priv, "enter\n");
+
+	retries = info->status.rates[0].count;
+	/* Sanity Check for retries */
+	if (retries > IWL_RATE_RETRY_TH)
+		retries = IWL_RATE_RETRY_TH;
+
+	first_index = sband->bitrates[info->status.rates[0].idx].hw_value;
+	if ((first_index < 0) || (first_index >= IWL_RATE_COUNT_3945)) {
+		IWL_DEBUG_RATE(priv, "leave: Rate out of bounds: %d\n", first_index);
+		return;
+	}
+
+	if (!priv_sta) {
+		IWL_DEBUG_RATE(priv, "leave: No STA priv data to update!\n");
+		return;
+	}
+
+	/* Treat uninitialized rate scaling data same as non-existing. */
+	if (!rs_sta->priv) {
+		IWL_DEBUG_RATE(priv, "leave: STA priv data uninitialized!\n");
+		return;
+	}
+
+
+	rs_sta->tx_packets++;
+
+	scale_rate_index = first_index;
+	last_index = first_index;
+
+	/*
+	 * Update the window 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
+	 * priv value 'retry_rate' vs. rate specific
+	 *
+	 * On exit from this while loop last_index indicates the rate
+	 * at which the frame was finally transmitted (or failed if no
+	 * ACK)
+	 */
+	while (retries > 1) {
+		if ((retries - 1) < priv->retry_rate) {
+			current_count = (retries - 1);
+			last_index = scale_rate_index;
+		} else {
+			current_count = priv->retry_rate;
+			last_index = iwl3945_rs_next_rate(priv,
+							 scale_rate_index);
+		}
+
+		/* Update this rate accounting for as many retries
+		 * as was used for it (per current_count) */
+		iwl3945_collect_tx_data(rs_sta,
+				    &rs_sta->win[scale_rate_index],
+				    0, current_count, scale_rate_index);
+		IWL_DEBUG_RATE(priv, "Update rate %d for %d retries.\n",
+			       scale_rate_index, current_count);
+
+		retries -= current_count;
+
+		scale_rate_index = last_index;
+	}
+
+
+	/* Update the last index window with success/failure based on ACK */
+	IWL_DEBUG_RATE(priv, "Update rate %d with %s.\n",
+		       last_index,
+		       (info->flags & IEEE80211_TX_STAT_ACK) ?
+		       "success" : "failure");
+	iwl3945_collect_tx_data(rs_sta,
+			    &rs_sta->win[last_index],
+			    info->flags & IEEE80211_TX_STAT_ACK, 1, last_index);
+
+	/* We updated the rate scale window -- 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);
+
+	IWL_DEBUG_RATE(priv, "leave\n");
+}
+
+static u16 iwl3945_get_adjacent_rate(struct iwl3945_rs_sta *rs_sta,
+				 u8 index, u16 rate_mask, enum ieee80211_band band)
+{
+	u8 high = IWL_RATE_INVALID;
+	u8 low = IWL_RATE_INVALID;
+	struct iwl_priv *priv __maybe_unused = rs_sta->priv;
+
+	/* 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 = index - 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 = index + 1;
+		for (mask = (1 << i); i < IWL_RATE_COUNT_3945;
+		     i++, mask <<= 1) {
+			if (rate_mask & mask) {
+				high = i;
+				break;
+			}
+		}
+
+		return (high << 8) | low;
+	}
+
+	low = index;
+	while (low != IWL_RATE_INVALID) {
+		if (rs_sta->tgg)
+			low = iwl3945_rates[low].prev_rs_tgg;
+		else
+			low = iwl3945_rates[low].prev_rs;
+		if (low == IWL_RATE_INVALID)
+			break;
+		if (rate_mask & (1 << low))
+			break;
+		IWL_DEBUG_RATE(priv, "Skipping masked lower rate: %d\n", low);
+	}
+
+	high = index;
+	while (high != IWL_RATE_INVALID) {
+		if (rs_sta->tgg)
+			high = iwl3945_rates[high].next_rs_tgg;
+		else
+			high = iwl3945_rates[high].next_rs;
+		if (high == IWL_RATE_INVALID)
+			break;
+		if (rate_mask & (1 << high))
+			break;
+		IWL_DEBUG_RATE(priv, "Skipping masked higher rate: %d\n", high);
+	}
+
+	return (high << 8) | low;
+}
+
+/**
+ * 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 index obtained below into the hw_mode's
+ * rate table and must reference the driver allocated rate table
+ *
+ */
+static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
+			void *priv_sta,	struct ieee80211_tx_rate_control *txrc)
+{
+	struct ieee80211_supported_band *sband = txrc->sband;
+	struct sk_buff *skb = txrc->skb;
+	u8 low = IWL_RATE_INVALID;
+	u8 high = IWL_RATE_INVALID;
+	u16 high_low;
+	int index;
+	struct iwl3945_rs_sta *rs_sta = priv_sta;
+	struct iwl3945_rate_scale_data *window = NULL;
+	int current_tpt = IWL_INVALID_VALUE;
+	int low_tpt = IWL_INVALID_VALUE;
+	int high_tpt = IWL_INVALID_VALUE;
+	u32 fail_count;
+	s8 scale_action = 0;
+	unsigned long flags;
+	u16 rate_mask = sta ? sta->supp_rates[sband->band] : 0;
+	s8 max_rate_idx = -1;
+	struct iwl_priv *priv __maybe_unused = (struct iwl_priv *)priv_r;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
+	IWL_DEBUG_RATE(priv, "enter\n");
+
+	/* Treat uninitialized rate scaling data same as non-existing. */
+	if (rs_sta && !rs_sta->priv) {
+		IWL_DEBUG_RATE(priv, "Rate scaling information not initialized yet.\n");
+		priv_sta = NULL;
+	}
+
+	if (rate_control_send_low(sta, priv_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 += IWL_FIRST_OFDM_RATE;
+	if ((max_rate_idx < 0) || (max_rate_idx >= IWL_RATE_COUNT))
+		max_rate_idx = -1;
+
+	index = min(rs_sta->last_txrate_idx & 0xffff, IWL_RATE_COUNT_3945 - 1);
+
+	if (sband->band == IEEE80211_BAND_5GHZ)
+		rate_mask = rate_mask << IWL_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 != IWL_RATE_INVALID) {
+		if (rs_sta->start_rate < index &&
+		   (rate_mask & (1 << rs_sta->start_rate)))
+			index = rs_sta->start_rate;
+		rs_sta->start_rate = IWL_RATE_INVALID;
+	}
+
+	/* force user max rate if set by user */
+	if ((max_rate_idx != -1) && (max_rate_idx < index)) {
+		if (rate_mask & (1 << max_rate_idx))
+			index = max_rate_idx;
+	}
+
+	window = &(rs_sta->win[index]);
+
+	fail_count = window->counter - window->success_counter;
+
+	if (((fail_count < IWL_RATE_MIN_FAILURE_TH) &&
+	     (window->success_counter < IWL_RATE_MIN_SUCCESS_TH))) {
+		spin_unlock_irqrestore(&rs_sta->lock, flags);
+
+		IWL_DEBUG_RATE(priv, "Invalid average_tpt on rate %d: "
+			       "counter: %d, success_counter: %d, "
+			       "expected_tpt is %sNULL\n",
+			       index,
+			       window->counter,
+			       window->success_counter,
+			       rs_sta->expected_tpt ? "not " : "");
+
+	   /* Can't calculate this yet; not enough history */
+		window->average_tpt = IWL_INVALID_VALUE;
+		goto out;
+
+	}
+
+	current_tpt = window->average_tpt;
+
+	high_low = iwl3945_get_adjacent_rate(rs_sta, index, 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 = IWL_RATE_INVALID;
+
+	/* Collect Measured throughputs of adjacent rates */
+	if (low != IWL_RATE_INVALID)
+		low_tpt = rs_sta->win[low].average_tpt;
+
+	if (high != IWL_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 ((window->success_ratio < IWL_RATE_DECREASE_TH) || !current_tpt) {
+		IWL_DEBUG_RATE(priv, "decrease rate because of low success_ratio\n");
+		scale_action = -1;
+	/* No throughput measured yet for adjacent rates,
+	 * try increase */
+	} else if ((low_tpt == IWL_INVALID_VALUE) &&
+		   (high_tpt == IWL_INVALID_VALUE)) {
+
+		if (high != IWL_RATE_INVALID && window->success_ratio >= IWL_RATE_INCREASE_TH)
+			scale_action = 1;
+		else if (low != IWL_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 != IWL_INVALID_VALUE) &&
+		 (high_tpt != IWL_INVALID_VALUE) &&
+		 (low_tpt < current_tpt) && (high_tpt < current_tpt)) {
+
+		IWL_DEBUG_RATE(priv, "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 != IWL_INVALID_VALUE) {
+
+			/* High rate has better throughput, Increase
+			 * rate */
+			if (high_tpt > current_tpt &&
+				window->success_ratio >= IWL_RATE_INCREASE_TH)
+				scale_action = 1;
+			else {
+				IWL_DEBUG_RATE(priv,
+				    "decrease rate because of high tpt\n");
+				scale_action = 0;
+			}
+		} else if (low_tpt != IWL_INVALID_VALUE) {
+			if (low_tpt > current_tpt) {
+				IWL_DEBUG_RATE(priv,
+				    "decrease rate because of low tpt\n");
+				scale_action = -1;
+			} else if (window->success_ratio >= IWL_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 != IWL_RATE_INVALID) &&
+		    ((window->success_ratio > IWL_RATE_HIGH_TH) ||
+		     (current_tpt > (100 * rs_sta->expected_tpt[low]))))
+		scale_action = 0;
+
+	switch (scale_action) {
+	case -1:
+
+		/* Decrese rate */
+		if (low != IWL_RATE_INVALID)
+			index = low;
+		break;
+
+	case 1:
+		/* Increase rate */
+		if (high != IWL_RATE_INVALID)
+			index = high;
+
+		break;
+
+	case 0:
+	default:
+		/* No change */
+		break;
+	}
+
+	IWL_DEBUG_RATE(priv, "Selected %d (action %d) - low %d high %d\n",
+		       index, scale_action, low, high);
+
+ out:
+
+	rs_sta->last_txrate_idx = index;
+	if (sband->band == IEEE80211_BAND_5GHZ)
+		info->control.rates[0].idx = rs_sta->last_txrate_idx -
+				IWL_FIRST_OFDM_RATE;
+	else
+		info->control.rates[0].idx = rs_sta->last_txrate_idx;
+
+	IWL_DEBUG_RATE(priv, "leave: %d\n", index);
+}
+
+#ifdef CONFIG_MAC80211_DEBUGFS
+static int iwl3945_open_file_generic(struct inode *inode, struct file *file)
+{
+	file->private_data = inode->i_private;
+	return 0;
+}
+
+static ssize_t iwl3945_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 iwl3945_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 index=%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 < IWL_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 = iwl3945_sta_dbgfs_stats_table_read,
+	.open = iwl3945_open_file_generic,
+	.llseek = default_llseek,
+};
+
+static void iwl3945_add_debugfs(void *priv, void *priv_sta,
+				struct dentry *dir)
+{
+	struct iwl3945_rs_sta *lq_sta = priv_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 iwl3945_remove_debugfs(void *priv, void *priv_sta)
+{
+	struct iwl3945_rs_sta *lq_sta = priv_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 rs_rate_init_stub(void *priv_r, struct ieee80211_supported_band *sband,
+			      struct ieee80211_sta *sta, void *priv_sta)
+{
+}
+
+static struct rate_control_ops rs_ops = {
+	.module = NULL,
+	.name = RS_NAME,
+	.tx_status = rs_tx_status,
+	.get_rate = rs_get_rate,
+	.rate_init = rs_rate_init_stub,
+	.alloc = rs_alloc,
+	.free = rs_free,
+	.alloc_sta = rs_alloc_sta,
+	.free_sta = rs_free_sta,
+#ifdef CONFIG_MAC80211_DEBUGFS
+	.add_sta_debugfs = iwl3945_add_debugfs,
+	.remove_sta_debugfs = iwl3945_remove_debugfs,
+#endif
+
+};
+void iwl3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
+{
+	struct iwl_priv *priv = hw->priv;
+	s32 rssi = 0;
+	unsigned long flags;
+	struct iwl3945_rs_sta *rs_sta;
+	struct ieee80211_sta *sta;
+	struct iwl3945_sta_priv *psta;
+
+	IWL_DEBUG_RATE(priv, "enter\n");
+
+	rcu_read_lock();
+
+	sta = ieee80211_find_sta(priv->contexts[IWL_RXON_CTX_BSS].vif,
+				 priv->stations[sta_id].sta.sta.addr);
+	if (!sta) {
+		IWL_DEBUG_RATE(priv, "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 (priv->band) {
+	case IEEE80211_BAND_2GHZ:
+		/* TODO: this always does G, not a regression */
+		if (priv->contexts[IWL_RXON_CTX_BSS].active.flags &
+						RXON_FLG_TGG_PROTECT_MSK) {
+			rs_sta->tgg = 1;
+			rs_sta->expected_tpt = iwl3945_expected_tpt_g_prot;
+		} else
+			rs_sta->expected_tpt = iwl3945_expected_tpt_g;
+		break;
+
+	case IEEE80211_BAND_5GHZ:
+		rs_sta->expected_tpt = iwl3945_expected_tpt_a;
+		break;
+	case IEEE80211_NUM_BANDS:
+		BUG();
+		break;
+	}
+
+	spin_unlock_irqrestore(&rs_sta->lock, flags);
+
+	rssi = priv->_3945.last_rx_rssi;
+	if (rssi == 0)
+		rssi = IWL_MIN_RSSI_VAL;
+
+	IWL_DEBUG_RATE(priv, "Network RSSI: %d\n", rssi);
+
+	rs_sta->start_rate = iwl3945_get_rate_index_by_rssi(rssi, priv->band);
+
+	IWL_DEBUG_RATE(priv, "leave: rssi %d assign rate index: "
+		       "%d (plcp 0x%x)\n", rssi, rs_sta->start_rate,
+		       iwl3945_rates[rs_sta->start_rate].plcp);
+	rcu_read_unlock();
+}
+
+int iwl3945_rate_control_register(void)
+{
+	return ieee80211_rate_control_register(&rs_ops);
+}
+
+void iwl3945_rate_control_unregister(void)
+{
+	ieee80211_rate_control_unregister(&rs_ops);
+}
+
+