Merge branch 'linus' into timers/hpet
[linux-2.6] / drivers / net / wireless / iwlwifi / iwl-3945-rs.c
1 /******************************************************************************
2  *
3  * Copyright(c) 2005 - 2008 Intel Corporation. All rights reserved.
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms of version 2 of the GNU General Public License as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  *
14  * You should have received a copy of the GNU General Public License along with
15  * this program; if not, write to the Free Software Foundation, Inc.,
16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
17  *
18  * The full GNU General Public License is included in this distribution in the
19  * file called LICENSE.
20  *
21  * Contact Information:
22  *  Intel Linux Wireless <ilw@linux.intel.com>
23  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
24  *
25  *****************************************************************************/
26
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/skbuff.h>
30 #include <linux/wireless.h>
31 #include <net/mac80211.h>
32
33 #include <linux/netdevice.h>
34 #include <linux/etherdevice.h>
35 #include <linux/delay.h>
36
37 #include <linux/workqueue.h>
38
39 #include "iwl-3945.h"
40
41 #define RS_NAME "iwl-3945-rs"
42
43 struct iwl3945_rate_scale_data {
44         u64 data;
45         s32 success_counter;
46         s32 success_ratio;
47         s32 counter;
48         s32 average_tpt;
49         unsigned long stamp;
50 };
51
52 struct iwl3945_rs_sta {
53         spinlock_t lock;
54         s32 *expected_tpt;
55         unsigned long last_partial_flush;
56         unsigned long last_flush;
57         u32 flush_time;
58         u32 last_tx_packets;
59         u32 tx_packets;
60         u8 tgg;
61         u8 flush_pending;
62         u8 start_rate;
63         u8 ibss_sta_added;
64         struct timer_list rate_scale_flush;
65         struct iwl3945_rate_scale_data win[IWL_RATE_COUNT];
66 #ifdef CONFIG_MAC80211_DEBUGFS
67         struct dentry *rs_sta_dbgfs_stats_table_file;
68 #endif
69
70         /* used to be in sta_info */
71         int last_txrate_idx;
72 };
73
74 static s32 iwl3945_expected_tpt_g[IWL_RATE_COUNT] = {
75         7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
76 };
77
78 static s32 iwl3945_expected_tpt_g_prot[IWL_RATE_COUNT] = {
79         7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
80 };
81
82 static s32 iwl3945_expected_tpt_a[IWL_RATE_COUNT] = {
83         0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186
84 };
85
86 static s32 iwl3945_expected_tpt_b[IWL_RATE_COUNT] = {
87         7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
88 };
89
90 struct iwl3945_tpt_entry {
91         s8 min_rssi;
92         u8 index;
93 };
94
95 static struct iwl3945_tpt_entry iwl3945_tpt_table_a[] = {
96         {-60, IWL_RATE_54M_INDEX},
97         {-64, IWL_RATE_48M_INDEX},
98         {-72, IWL_RATE_36M_INDEX},
99         {-80, IWL_RATE_24M_INDEX},
100         {-84, IWL_RATE_18M_INDEX},
101         {-85, IWL_RATE_12M_INDEX},
102         {-87, IWL_RATE_9M_INDEX},
103         {-89, IWL_RATE_6M_INDEX}
104 };
105
106 static struct iwl3945_tpt_entry iwl3945_tpt_table_g[] = {
107         {-60, IWL_RATE_54M_INDEX},
108         {-64, IWL_RATE_48M_INDEX},
109         {-68, IWL_RATE_36M_INDEX},
110         {-80, IWL_RATE_24M_INDEX},
111         {-84, IWL_RATE_18M_INDEX},
112         {-85, IWL_RATE_12M_INDEX},
113         {-86, IWL_RATE_11M_INDEX},
114         {-88, IWL_RATE_5M_INDEX},
115         {-90, IWL_RATE_2M_INDEX},
116         {-92, IWL_RATE_1M_INDEX}
117 };
118
119 #define IWL_RATE_MAX_WINDOW          62
120 #define IWL_RATE_FLUSH           (3*HZ)
121 #define IWL_RATE_WIN_FLUSH       (HZ/2)
122 #define IWL_RATE_HIGH_TH          11520
123 #define IWL_SUCCESS_UP_TH          8960
124 #define IWL_SUCCESS_DOWN_TH       10880
125 #define IWL_RATE_MIN_FAILURE_TH       8
126 #define IWL_RATE_MIN_SUCCESS_TH       8
127 #define IWL_RATE_DECREASE_TH       1920
128
129 static u8 iwl3945_get_rate_index_by_rssi(s32 rssi, enum ieee80211_band band)
130 {
131         u32 index = 0;
132         u32 table_size = 0;
133         struct iwl3945_tpt_entry *tpt_table = NULL;
134
135         if ((rssi < IWL_MIN_RSSI_VAL) || (rssi > IWL_MAX_RSSI_VAL))
136                 rssi = IWL_MIN_RSSI_VAL;
137
138         switch (band) {
139         case IEEE80211_BAND_2GHZ:
140                 tpt_table = iwl3945_tpt_table_g;
141                 table_size = ARRAY_SIZE(iwl3945_tpt_table_g);
142                 break;
143
144         case IEEE80211_BAND_5GHZ:
145                 tpt_table = iwl3945_tpt_table_a;
146                 table_size = ARRAY_SIZE(iwl3945_tpt_table_a);
147                 break;
148
149         default:
150                 BUG();
151                 break;
152         }
153
154         while ((index < table_size) && (rssi < tpt_table[index].min_rssi))
155                 index++;
156
157         index = min(index, (table_size - 1));
158
159         return tpt_table[index].index;
160 }
161
162 static void iwl3945_clear_window(struct iwl3945_rate_scale_data *window)
163 {
164         window->data = 0;
165         window->success_counter = 0;
166         window->success_ratio = -1;
167         window->counter = 0;
168         window->average_tpt = IWL_INV_TPT;
169         window->stamp = 0;
170 }
171
172 /**
173  * iwl3945_rate_scale_flush_windows - flush out the rate scale windows
174  *
175  * Returns the number of windows that have gathered data but were
176  * not flushed.  If there were any that were not flushed, then
177  * reschedule the rate flushing routine.
178  */
179 static int iwl3945_rate_scale_flush_windows(struct iwl3945_rs_sta *rs_sta)
180 {
181         int unflushed = 0;
182         int i;
183         unsigned long flags;
184
185         /*
186          * For each rate, if we have collected data on that rate
187          * and it has been more than IWL_RATE_WIN_FLUSH
188          * since we flushed, clear out the gathered statistics
189          */
190         for (i = 0; i < IWL_RATE_COUNT; i++) {
191                 if (!rs_sta->win[i].counter)
192                         continue;
193
194                 spin_lock_irqsave(&rs_sta->lock, flags);
195                 if (time_after(jiffies, rs_sta->win[i].stamp +
196                                IWL_RATE_WIN_FLUSH)) {
197                         IWL_DEBUG_RATE("flushing %d samples of rate "
198                                        "index %d\n",
199                                        rs_sta->win[i].counter, i);
200                         iwl3945_clear_window(&rs_sta->win[i]);
201                 } else
202                         unflushed++;
203                 spin_unlock_irqrestore(&rs_sta->lock, flags);
204         }
205
206         return unflushed;
207 }
208
209 #define IWL_RATE_FLUSH_MAX              5000    /* msec */
210 #define IWL_RATE_FLUSH_MIN              50      /* msec */
211 #define IWL_AVERAGE_PACKETS             1500
212
213 static void iwl3945_bg_rate_scale_flush(unsigned long data)
214 {
215         struct iwl3945_rs_sta *rs_sta = (void *)data;
216         int unflushed = 0;
217         unsigned long flags;
218         u32 packet_count, duration, pps;
219
220         IWL_DEBUG_RATE("enter\n");
221
222         unflushed = iwl3945_rate_scale_flush_windows(rs_sta);
223
224         spin_lock_irqsave(&rs_sta->lock, flags);
225
226         /* Number of packets Rx'd since last time this timer ran */
227         packet_count = (rs_sta->tx_packets - rs_sta->last_tx_packets) + 1;
228
229         rs_sta->last_tx_packets = rs_sta->tx_packets + 1;
230
231         if (unflushed) {
232                 duration =
233                     jiffies_to_msecs(jiffies - rs_sta->last_partial_flush);
234
235                 IWL_DEBUG_RATE("Tx'd %d packets in %dms\n",
236                                packet_count, duration);
237
238                 /* Determine packets per second */
239                 if (duration)
240                         pps = (packet_count * 1000) / duration;
241                 else
242                         pps = 0;
243
244                 if (pps) {
245                         duration = (IWL_AVERAGE_PACKETS * 1000) / pps;
246                         if (duration < IWL_RATE_FLUSH_MIN)
247                                 duration = IWL_RATE_FLUSH_MIN;
248                         else if (duration > IWL_RATE_FLUSH_MAX)
249                                 duration = IWL_RATE_FLUSH_MAX;
250                 } else
251                         duration = IWL_RATE_FLUSH_MAX;
252
253                 rs_sta->flush_time = msecs_to_jiffies(duration);
254
255                 IWL_DEBUG_RATE("new flush period: %d msec ave %d\n",
256                                duration, packet_count);
257
258                 mod_timer(&rs_sta->rate_scale_flush, jiffies +
259                           rs_sta->flush_time);
260
261                 rs_sta->last_partial_flush = jiffies;
262         } else {
263                 rs_sta->flush_time = IWL_RATE_FLUSH;
264                 rs_sta->flush_pending = 0;
265         }
266         /* If there weren't any unflushed entries, we don't schedule the timer
267          * to run again */
268
269         rs_sta->last_flush = jiffies;
270
271         spin_unlock_irqrestore(&rs_sta->lock, flags);
272
273         IWL_DEBUG_RATE("leave\n");
274 }
275
276 /**
277  * iwl3945_collect_tx_data - Update the success/failure sliding window
278  *
279  * We keep a sliding window of the last 64 packets transmitted
280  * at this rate.  window->data contains the bitmask of successful
281  * packets.
282  */
283 static void iwl3945_collect_tx_data(struct iwl3945_rs_sta *rs_sta,
284                                 struct iwl3945_rate_scale_data *window,
285                                 int success, int retries, int index)
286 {
287         unsigned long flags;
288         s32 fail_count;
289
290         if (!retries) {
291                 IWL_DEBUG_RATE("leave: retries == 0 -- should be at least 1\n");
292                 return;
293         }
294
295         spin_lock_irqsave(&rs_sta->lock, flags);
296         while (retries--) {
297
298                 /* If we have filled up the window then subtract one from the
299                  * success counter if the high-bit is counting toward
300                  * success */
301                 if (window->counter == IWL_RATE_MAX_WINDOW) {
302                         if (window->data & (1ULL << (IWL_RATE_MAX_WINDOW - 1)))
303                                 window->success_counter--;
304                 } else
305                         window->counter++;
306
307                 /* Slide the window to the left one bit */
308                 window->data = (window->data << 1);
309
310                 /* If this packet was a success then set the low bit high */
311                 if (success) {
312                         window->success_counter++;
313                         window->data |= 1;
314                 }
315
316                 /* window->counter can't be 0 -- it is either >0 or
317                  * IWL_RATE_MAX_WINDOW */
318                 window->success_ratio = 12800 * window->success_counter /
319                     window->counter;
320
321                 /* Tag this window as having been updated */
322                 window->stamp = jiffies;
323
324         }
325
326         fail_count = window->counter - window->success_counter;
327         if ((fail_count >= IWL_RATE_MIN_FAILURE_TH) ||
328             (window->success_counter >= IWL_RATE_MIN_SUCCESS_TH))
329                 window->average_tpt = ((window->success_ratio *
330                                 rs_sta->expected_tpt[index] + 64) / 128);
331         else
332                 window->average_tpt = IWL_INV_TPT;
333
334         spin_unlock_irqrestore(&rs_sta->lock, flags);
335
336 }
337
338 static void rs_rate_init(void *priv_r, struct ieee80211_supported_band *sband,
339                          struct ieee80211_sta *sta, void *priv_sta)
340 {
341         struct iwl3945_rs_sta *rs_sta = priv_sta;
342         struct iwl3945_priv *priv = (struct iwl3945_priv *)priv_r;
343         int i;
344
345         IWL_DEBUG_RATE("enter\n");
346
347         /* TODO: what is a good starting rate for STA? About middle? Maybe not
348          * the lowest or the highest rate.. Could consider using RSSI from
349          * previous packets? Need to have IEEE 802.1X auth succeed immediately
350          * after assoc.. */
351
352         for (i = sband->n_bitrates - 1; i >= 0; i--) {
353                 if (sta->supp_rates[sband->band] & (1 << i)) {
354                         rs_sta->last_txrate_idx = i;
355                         break;
356                 }
357         }
358
359         priv->sta_supp_rates = sta->supp_rates[sband->band];
360         /* For 5 GHz band it start at IWL_FIRST_OFDM_RATE */
361         if (sband->band == IEEE80211_BAND_5GHZ) {
362                 rs_sta->last_txrate_idx += IWL_FIRST_OFDM_RATE;
363                 priv->sta_supp_rates = priv->sta_supp_rates <<
364                                                 IWL_FIRST_OFDM_RATE;
365         }
366
367
368         IWL_DEBUG_RATE("leave\n");
369 }
370
371 static void *rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
372 {
373         return hw->priv;
374 }
375
376 /* rate scale requires free function to be implemented */
377 static void rs_free(void *priv)
378 {
379         return;
380 }
381
382 static void *rs_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
383 {
384         struct iwl3945_rs_sta *rs_sta;
385         struct iwl3945_sta_priv *psta = (void *) sta->drv_priv;
386         int i;
387
388         /*
389          * XXX: If it's using sta->drv_priv anyway, it might
390          *      as well just put all the information there.
391          */
392
393         IWL_DEBUG_RATE("enter\n");
394
395         rs_sta = kzalloc(sizeof(struct iwl3945_rs_sta), gfp);
396         if (!rs_sta) {
397                 IWL_DEBUG_RATE("leave: ENOMEM\n");
398                 return NULL;
399         }
400
401         psta->rs_sta = rs_sta;
402
403         spin_lock_init(&rs_sta->lock);
404
405         rs_sta->start_rate = IWL_RATE_INVALID;
406
407         /* default to just 802.11b */
408         rs_sta->expected_tpt = iwl3945_expected_tpt_b;
409
410         rs_sta->last_partial_flush = jiffies;
411         rs_sta->last_flush = jiffies;
412         rs_sta->flush_time = IWL_RATE_FLUSH;
413         rs_sta->last_tx_packets = 0;
414         rs_sta->ibss_sta_added = 0;
415
416         init_timer(&rs_sta->rate_scale_flush);
417         rs_sta->rate_scale_flush.data = (unsigned long)rs_sta;
418         rs_sta->rate_scale_flush.function = &iwl3945_bg_rate_scale_flush;
419
420         for (i = 0; i < IWL_RATE_COUNT; i++)
421                 iwl3945_clear_window(&rs_sta->win[i]);
422
423         IWL_DEBUG_RATE("leave\n");
424
425         return rs_sta;
426 }
427
428 static void rs_free_sta(void *priv, struct ieee80211_sta *sta,
429                         void *priv_sta)
430 {
431         struct iwl3945_sta_priv *psta = (void *) sta->drv_priv;
432         struct iwl3945_rs_sta *rs_sta = priv_sta;
433
434         psta->rs_sta = NULL;
435
436         IWL_DEBUG_RATE("enter\n");
437         del_timer_sync(&rs_sta->rate_scale_flush);
438         kfree(rs_sta);
439         IWL_DEBUG_RATE("leave\n");
440 }
441
442
443 /**
444  * rs_tx_status - Update rate control values based on Tx results
445  *
446  * NOTE: Uses iwl3945_priv->retry_rate for the # of retries attempted by
447  * the hardware for each rate.
448  */
449 static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband,
450                          struct ieee80211_sta *sta, void *priv_sta,
451                          struct sk_buff *skb)
452 {
453         s8 retries = 0, current_count;
454         int scale_rate_index, first_index, last_index;
455         unsigned long flags;
456         struct iwl3945_priv *priv = (struct iwl3945_priv *)priv_rate;
457         struct iwl3945_rs_sta *rs_sta = priv_sta;
458         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
459
460         IWL_DEBUG_RATE("enter\n");
461
462         retries = info->status.rates[0].count;
463
464         first_index = sband->bitrates[info->status.rates[0].idx].hw_value;
465         if ((first_index < 0) || (first_index >= IWL_RATE_COUNT)) {
466                 IWL_DEBUG_RATE("leave: Rate out of bounds: %d\n", first_index);
467                 return;
468         }
469
470         if (!priv_sta) {
471                 IWL_DEBUG_RATE("leave: No STA priv data to update!\n");
472                 return;
473         }
474
475         rs_sta->tx_packets++;
476
477         scale_rate_index = first_index;
478         last_index = first_index;
479
480         /*
481          * Update the window for each rate.  We determine which rates
482          * were Tx'd based on the total number of retries vs. the number
483          * of retries configured for each rate -- currently set to the
484          * priv value 'retry_rate' vs. rate specific
485          *
486          * On exit from this while loop last_index indicates the rate
487          * at which the frame was finally transmitted (or failed if no
488          * ACK)
489          */
490         while (retries > 1) {
491                 if ((retries - 1) < priv->retry_rate) {
492                         current_count = (retries - 1);
493                         last_index = scale_rate_index;
494                 } else {
495                         current_count = priv->retry_rate;
496                         last_index = iwl3945_rs_next_rate(priv,
497                                                          scale_rate_index);
498                 }
499
500                 /* Update this rate accounting for as many retries
501                  * as was used for it (per current_count) */
502                 iwl3945_collect_tx_data(rs_sta,
503                                     &rs_sta->win[scale_rate_index],
504                                     0, current_count, scale_rate_index);
505                 IWL_DEBUG_RATE("Update rate %d for %d retries.\n",
506                                scale_rate_index, current_count);
507
508                 retries -= current_count;
509
510                 scale_rate_index = last_index;
511         }
512
513
514         /* Update the last index window with success/failure based on ACK */
515         IWL_DEBUG_RATE("Update rate %d with %s.\n",
516                        last_index,
517                        (info->flags & IEEE80211_TX_STAT_ACK) ?
518                        "success" : "failure");
519         iwl3945_collect_tx_data(rs_sta,
520                             &rs_sta->win[last_index],
521                             info->flags & IEEE80211_TX_STAT_ACK, 1, last_index);
522
523         /* We updated the rate scale window -- if its been more than
524          * flush_time since the last run, schedule the flush
525          * again */
526         spin_lock_irqsave(&rs_sta->lock, flags);
527
528         if (!rs_sta->flush_pending &&
529             time_after(jiffies, rs_sta->last_flush +
530                        rs_sta->flush_time)) {
531
532                 rs_sta->last_partial_flush = jiffies;
533                 rs_sta->flush_pending = 1;
534                 mod_timer(&rs_sta->rate_scale_flush,
535                           jiffies + rs_sta->flush_time);
536         }
537
538         spin_unlock_irqrestore(&rs_sta->lock, flags);
539
540         IWL_DEBUG_RATE("leave\n");
541
542         return;
543 }
544
545 static u16 iwl3945_get_adjacent_rate(struct iwl3945_rs_sta *rs_sta,
546                                  u8 index, u16 rate_mask, enum ieee80211_band band)
547 {
548         u8 high = IWL_RATE_INVALID;
549         u8 low = IWL_RATE_INVALID;
550
551         /* 802.11A walks to the next literal adjacent rate in
552          * the rate table */
553         if (unlikely(band == IEEE80211_BAND_5GHZ)) {
554                 int i;
555                 u32 mask;
556
557                 /* Find the previous rate that is in the rate mask */
558                 i = index - 1;
559                 for (mask = (1 << i); i >= 0; i--, mask >>= 1) {
560                         if (rate_mask & mask) {
561                                 low = i;
562                                 break;
563                         }
564                 }
565
566                 /* Find the next rate that is in the rate mask */
567                 i = index + 1;
568                 for (mask = (1 << i); i < IWL_RATE_COUNT; i++, mask <<= 1) {
569                         if (rate_mask & mask) {
570                                 high = i;
571                                 break;
572                         }
573                 }
574
575                 return (high << 8) | low;
576         }
577
578         low = index;
579         while (low != IWL_RATE_INVALID) {
580                 if (rs_sta->tgg)
581                         low = iwl3945_rates[low].prev_rs_tgg;
582                 else
583                         low = iwl3945_rates[low].prev_rs;
584                 if (low == IWL_RATE_INVALID)
585                         break;
586                 if (rate_mask & (1 << low))
587                         break;
588                 IWL_DEBUG_RATE("Skipping masked lower rate: %d\n", low);
589         }
590
591         high = index;
592         while (high != IWL_RATE_INVALID) {
593                 if (rs_sta->tgg)
594                         high = iwl3945_rates[high].next_rs_tgg;
595                 else
596                         high = iwl3945_rates[high].next_rs;
597                 if (high == IWL_RATE_INVALID)
598                         break;
599                 if (rate_mask & (1 << high))
600                         break;
601                 IWL_DEBUG_RATE("Skipping masked higher rate: %d\n", high);
602         }
603
604         return (high << 8) | low;
605 }
606
607 /**
608  * rs_get_rate - find the rate for the requested packet
609  *
610  * Returns the ieee80211_rate structure allocated by the driver.
611  *
612  * The rate control algorithm has no internal mapping between hw_mode's
613  * rate ordering and the rate ordering used by the rate control algorithm.
614  *
615  * The rate control algorithm uses a single table of rates that goes across
616  * the entire A/B/G spectrum vs. being limited to just one particular
617  * hw_mode.
618  *
619  * As such, we can't convert the index obtained below into the hw_mode's
620  * rate table and must reference the driver allocated rate table
621  *
622  */
623 static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
624                         void *priv_sta, struct ieee80211_tx_rate_control *txrc)
625 {
626         struct ieee80211_supported_band *sband = txrc->sband;
627         struct sk_buff *skb = txrc->skb;
628         u8 low = IWL_RATE_INVALID;
629         u8 high = IWL_RATE_INVALID;
630         u16 high_low;
631         int index;
632         struct iwl3945_rs_sta *rs_sta = priv_sta;
633         struct iwl3945_rate_scale_data *window = NULL;
634         int current_tpt = IWL_INV_TPT;
635         int low_tpt = IWL_INV_TPT;
636         int high_tpt = IWL_INV_TPT;
637         u32 fail_count;
638         s8 scale_action = 0;
639         unsigned long flags;
640         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
641         u16 fc;
642         u16 rate_mask = 0;
643         struct iwl3945_priv *priv = (struct iwl3945_priv *)priv_r;
644         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
645
646         IWL_DEBUG_RATE("enter\n");
647
648         if (sta)
649                 rate_mask = sta->supp_rates[sband->band];
650
651         /* Send management frames and broadcast/multicast data using lowest
652          * rate. */
653         fc = le16_to_cpu(hdr->frame_control);
654         if ((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
655             is_multicast_ether_addr(hdr->addr1) ||
656             !sta || !priv_sta) {
657                 IWL_DEBUG_RATE("leave: No STA priv data to update!\n");
658                 if (!rate_mask)
659                         info->control.rates[0].idx =
660                                         rate_lowest_index(sband, NULL);
661                 else
662                         info->control.rates[0].idx =
663                                         rate_lowest_index(sband, sta);
664                 return;
665         }
666
667         index = min(rs_sta->last_txrate_idx & 0xffff, IWL_RATE_COUNT - 1);
668
669         if (sband->band == IEEE80211_BAND_5GHZ)
670                 rate_mask = rate_mask << IWL_FIRST_OFDM_RATE;
671
672         if ((priv->iw_mode == NL80211_IFTYPE_ADHOC) &&
673             !rs_sta->ibss_sta_added) {
674                 u8 sta_id = iwl3945_hw_find_station(priv, hdr->addr1);
675
676                 if (sta_id == IWL_INVALID_STATION) {
677                         IWL_DEBUG_RATE("LQ: ADD station %pm\n",
678                                        hdr->addr1);
679                         sta_id = iwl3945_add_station(priv,
680                                     hdr->addr1, 0, CMD_ASYNC);
681                 }
682                 if (sta_id != IWL_INVALID_STATION)
683                         rs_sta->ibss_sta_added = 1;
684         }
685
686         spin_lock_irqsave(&rs_sta->lock, flags);
687
688         /* for recent assoc, choose best rate regarding
689          * to rssi value
690          */
691         if (rs_sta->start_rate != IWL_RATE_INVALID) {
692                 if (rs_sta->start_rate < index &&
693                    (rate_mask & (1 << rs_sta->start_rate)))
694                         index = rs_sta->start_rate;
695                 rs_sta->start_rate = IWL_RATE_INVALID;
696         }
697
698         window = &(rs_sta->win[index]);
699
700         fail_count = window->counter - window->success_counter;
701
702         if (((fail_count <= IWL_RATE_MIN_FAILURE_TH) &&
703              (window->success_counter < IWL_RATE_MIN_SUCCESS_TH))) {
704                 spin_unlock_irqrestore(&rs_sta->lock, flags);
705
706                 IWL_DEBUG_RATE("Invalid average_tpt on rate %d: "
707                                "counter: %d, success_counter: %d, "
708                                "expected_tpt is %sNULL\n",
709                                index,
710                                window->counter,
711                                window->success_counter,
712                                rs_sta->expected_tpt ? "not " : "");
713                 goto out;
714
715         }
716
717         current_tpt = window->average_tpt;
718
719         high_low = iwl3945_get_adjacent_rate(rs_sta, index, rate_mask,
720                                              sband->band);
721         low = high_low & 0xff;
722         high = (high_low >> 8) & 0xff;
723
724         if (low != IWL_RATE_INVALID)
725                 low_tpt = rs_sta->win[low].average_tpt;
726
727         if (high != IWL_RATE_INVALID)
728                 high_tpt = rs_sta->win[high].average_tpt;
729
730         spin_unlock_irqrestore(&rs_sta->lock, flags);
731
732         scale_action = 1;
733
734         if ((window->success_ratio < IWL_RATE_DECREASE_TH) || !current_tpt) {
735                 IWL_DEBUG_RATE("decrease rate because of low success_ratio\n");
736                 scale_action = -1;
737         } else if ((low_tpt == IWL_INV_TPT) && (high_tpt == IWL_INV_TPT))
738                 scale_action = 1;
739         else if ((low_tpt != IWL_INV_TPT) && (high_tpt != IWL_INV_TPT) &&
740                  (low_tpt < current_tpt) && (high_tpt < current_tpt)) {
741                 IWL_DEBUG_RATE("No action -- low [%d] & high [%d] < "
742                                "current_tpt [%d]\n",
743                                low_tpt, high_tpt, current_tpt);
744                 scale_action = 0;
745         } else {
746                 if (high_tpt != IWL_INV_TPT) {
747                         if (high_tpt > current_tpt)
748                                 scale_action = 1;
749                         else {
750                                 IWL_DEBUG_RATE
751                                     ("decrease rate because of high tpt\n");
752                                 scale_action = -1;
753                         }
754                 } else if (low_tpt != IWL_INV_TPT) {
755                         if (low_tpt > current_tpt) {
756                                 IWL_DEBUG_RATE
757                                     ("decrease rate because of low tpt\n");
758                                 scale_action = -1;
759                         } else
760                                 scale_action = 1;
761                 }
762         }
763
764         if (scale_action == -1) {
765                 if (window->success_ratio > IWL_SUCCESS_DOWN_TH)
766                         scale_action = 0;
767         } else if (scale_action == 1) {
768                 if (window->success_ratio < IWL_SUCCESS_UP_TH) {
769                         IWL_DEBUG_RATE("No action -- success_ratio [%d] < "
770                                "SUCCESS UP\n", window->success_ratio);
771                         scale_action = 0;
772                 }
773         }
774
775         switch (scale_action) {
776         case -1:
777                 if (low != IWL_RATE_INVALID)
778                         index = low;
779                 break;
780
781         case 1:
782                 if (high != IWL_RATE_INVALID)
783                         index = high;
784
785                 break;
786
787         case 0:
788         default:
789                 break;
790         }
791
792         IWL_DEBUG_RATE("Selected %d (action %d) - low %d high %d\n",
793                        index, scale_action, low, high);
794
795  out:
796
797         rs_sta->last_txrate_idx = index;
798         if (sband->band == IEEE80211_BAND_5GHZ)
799                 info->control.rates[0].idx = rs_sta->last_txrate_idx -
800                                 IWL_FIRST_OFDM_RATE;
801         else
802                 info->control.rates[0].idx = rs_sta->last_txrate_idx;
803
804         IWL_DEBUG_RATE("leave: %d\n", index);
805 }
806
807 #ifdef CONFIG_MAC80211_DEBUGFS
808 static int iwl3945_open_file_generic(struct inode *inode, struct file *file)
809 {
810         file->private_data = inode->i_private;
811         return 0;
812 }
813
814 static ssize_t iwl3945_sta_dbgfs_stats_table_read(struct file *file,
815                                                   char __user *user_buf,
816                                                   size_t count, loff_t *ppos)
817 {
818         char buff[1024];
819         int desc = 0;
820         int j;
821         struct iwl3945_rs_sta *lq_sta = file->private_data;
822
823         desc += sprintf(buff + desc, "tx packets=%d last rate index=%d\n"
824                         "rate=0x%X flush time %d\n",
825                         lq_sta->tx_packets,
826                         lq_sta->last_txrate_idx,
827                         lq_sta->start_rate, jiffies_to_msecs(lq_sta->flush_time));
828         for (j = 0; j < IWL_RATE_COUNT; j++) {
829                 desc += sprintf(buff+desc,
830                                 "counter=%d success=%d %%=%d\n",
831                                 lq_sta->win[j].counter,
832                                 lq_sta->win[j].success_counter,
833                                 lq_sta->win[j].success_ratio);
834         }
835         return simple_read_from_buffer(user_buf, count, ppos, buff, desc);
836 }
837
838 static const struct file_operations rs_sta_dbgfs_stats_table_ops = {
839         .read = iwl3945_sta_dbgfs_stats_table_read,
840         .open = iwl3945_open_file_generic,
841 };
842
843 static void iwl3945_add_debugfs(void *priv, void *priv_sta,
844                                 struct dentry *dir)
845 {
846         struct iwl3945_rs_sta *lq_sta = priv_sta;
847
848         lq_sta->rs_sta_dbgfs_stats_table_file =
849                 debugfs_create_file("rate_stats_table", 0600, dir,
850                 lq_sta, &rs_sta_dbgfs_stats_table_ops);
851
852 }
853
854 static void iwl3945_remove_debugfs(void *priv, void *priv_sta)
855 {
856         struct iwl3945_rs_sta *lq_sta = priv_sta;
857         debugfs_remove(lq_sta->rs_sta_dbgfs_stats_table_file);
858 }
859 #endif
860
861 static struct rate_control_ops rs_ops = {
862         .module = NULL,
863         .name = RS_NAME,
864         .tx_status = rs_tx_status,
865         .get_rate = rs_get_rate,
866         .rate_init = rs_rate_init,
867         .alloc = rs_alloc,
868         .free = rs_free,
869         .alloc_sta = rs_alloc_sta,
870         .free_sta = rs_free_sta,
871 #ifdef CONFIG_MAC80211_DEBUGFS
872         .add_sta_debugfs = iwl3945_add_debugfs,
873         .remove_sta_debugfs = iwl3945_remove_debugfs,
874 #endif
875
876 };
877
878 void iwl3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
879 {
880         struct iwl3945_priv *priv = hw->priv;
881         s32 rssi = 0;
882         unsigned long flags;
883         struct iwl3945_rs_sta *rs_sta;
884         struct ieee80211_sta *sta;
885         struct iwl3945_sta_priv *psta;
886
887         IWL_DEBUG_RATE("enter\n");
888
889         rcu_read_lock();
890
891         sta = ieee80211_find_sta(hw, priv->stations[sta_id].sta.sta.addr);
892         if (!sta) {
893                 rcu_read_unlock();
894                 return;
895         }
896
897         psta = (void *) sta->drv_priv;
898         rs_sta = psta->rs_sta;
899
900         spin_lock_irqsave(&rs_sta->lock, flags);
901
902         rs_sta->tgg = 0;
903         switch (priv->band) {
904         case IEEE80211_BAND_2GHZ:
905                 /* TODO: this always does G, not a regression */
906                 if (priv->active_rxon.flags & RXON_FLG_TGG_PROTECT_MSK) {
907                         rs_sta->tgg = 1;
908                         rs_sta->expected_tpt = iwl3945_expected_tpt_g_prot;
909                 } else
910                         rs_sta->expected_tpt = iwl3945_expected_tpt_g;
911                 break;
912
913         case IEEE80211_BAND_5GHZ:
914                 rs_sta->expected_tpt = iwl3945_expected_tpt_a;
915                 break;
916         case IEEE80211_NUM_BANDS:
917                 BUG();
918                 break;
919         }
920
921         spin_unlock_irqrestore(&rs_sta->lock, flags);
922
923         rssi = priv->last_rx_rssi;
924         if (rssi == 0)
925                 rssi = IWL_MIN_RSSI_VAL;
926
927         IWL_DEBUG(IWL_DL_INFO | IWL_DL_RATE, "Network RSSI: %d\n", rssi);
928
929         rs_sta->start_rate = iwl3945_get_rate_index_by_rssi(rssi, priv->band);
930
931         IWL_DEBUG_RATE("leave: rssi %d assign rate index: "
932                        "%d (plcp 0x%x)\n", rssi, rs_sta->start_rate,
933                        iwl3945_rates[rs_sta->start_rate].plcp);
934         rcu_read_unlock();
935 }
936
937 int iwl3945_rate_control_register(void)
938 {
939         return ieee80211_rate_control_register(&rs_ops);
940 }
941
942 void iwl3945_rate_control_unregister(void)
943 {
944         ieee80211_rate_control_unregister(&rs_ops);
945 }
946
947