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

Intel WiFi devices 3945 and 4965 now have their own driver in the folder

	drivers/net/wireless/iwlegacy

Add support to build these drivers independently of the driver for
AGN devices. Selecting the 3945 builds iwl3945.ko and iwl_legacy.ko,
and selecting the 4965 builds iwl4965.ko and iwl_legacy.ko. iwl-legacy.ko
contains code shared between both devices.

The 3945 is an ABG/BG device, with no support for 802.11n. The 4965 is a 2x3
ABGN device.

Signed-off-by: Meenakshi Venkataraman <meenakshi.venkataraman@intel.com>
Acked-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

1 files changed, 994 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlegacy/iwl-3945-rs.c b/drivers/net/wireless/iwlegacy/iwl-3945-rs.c
new file mode 100644
index 000000000000..4fabc5439858
--- /dev/null
+++ b/drivers/net/wireless/iwlegacy/iwl-3945-rs.c
@@ -0,0 +1,994 @@
+/******************************************************************************
+ *
+ * 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/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 *iwl3945_rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+{
+        return hw->priv;
+}
+
+/* rate scale requires free function to be implemented */
+static void iwl3945_rs_free(void *priv)
+{
+        return;
+}
+
+static void *iwl3945_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 iwl3945_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);
+}
+
+
+/**
+ * iwl3945_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 iwl3945_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;
+}
+
+/**
+ * iwl3945_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 iwl3945_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 iwl3945_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 = iwl3945_rs_tx_status,
+        .get_rate = iwl3945_rs_get_rate,
+        .rate_init = iwl3945_rs_rate_init_stub,
+        .alloc = iwl3945_rs_alloc,
+        .free = iwl3945_rs_free,
+        .alloc_sta = iwl3945_rs_alloc_sta,
+        .free_sta = iwl3945_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);
+}