70bee1a4d87679e57cafdb01fa22968ec823f20e
[linux-2.6.git] / drivers / net / wireless / iwlegacy / 3945-rs.c
1 /******************************************************************************
2  *
3  * Copyright(c) 2005 - 2011 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/slab.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 "commands.h"
40 #include "3945.h"
41
42 #define RS_NAME "iwl-3945-rs"
43
44 static s32 il3945_expected_tpt_g[RATE_COUNT_3945] = {
45         7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
46 };
47
48 static s32 il3945_expected_tpt_g_prot[RATE_COUNT_3945] = {
49         7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
50 };
51
52 static s32 il3945_expected_tpt_a[RATE_COUNT_3945] = {
53         0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186
54 };
55
56 static s32 il3945_expected_tpt_b[RATE_COUNT_3945] = {
57         7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
58 };
59
60 struct il3945_tpt_entry {
61         s8 min_rssi;
62         u8 idx;
63 };
64
65 static struct il3945_tpt_entry il3945_tpt_table_a[] = {
66         {-60, RATE_54M_IDX},
67         {-64, RATE_48M_IDX},
68         {-72, RATE_36M_IDX},
69         {-80, RATE_24M_IDX},
70         {-84, RATE_18M_IDX},
71         {-85, RATE_12M_IDX},
72         {-87, RATE_9M_IDX},
73         {-89, RATE_6M_IDX}
74 };
75
76 static struct il3945_tpt_entry il3945_tpt_table_g[] = {
77         {-60, RATE_54M_IDX},
78         {-64, RATE_48M_IDX},
79         {-68, RATE_36M_IDX},
80         {-80, RATE_24M_IDX},
81         {-84, RATE_18M_IDX},
82         {-85, RATE_12M_IDX},
83         {-86, RATE_11M_IDX},
84         {-88, RATE_5M_IDX},
85         {-90, RATE_2M_IDX},
86         {-92, RATE_1M_IDX}
87 };
88
89 #define RATE_MAX_WINDOW         62
90 #define RATE_FLUSH              (3*HZ)
91 #define RATE_WIN_FLUSH          (HZ/2)
92 #define IL39_RATE_HIGH_TH       11520
93 #define IL_SUCCESS_UP_TH        8960
94 #define IL_SUCCESS_DOWN_TH      10880
95 #define RATE_MIN_FAILURE_TH     6
96 #define RATE_MIN_SUCCESS_TH     8
97 #define RATE_DECREASE_TH        1920
98 #define RATE_RETRY_TH           15
99
100 static u8
101 il3945_get_rate_idx_by_rssi(s32 rssi, enum ieee80211_band band)
102 {
103         u32 idx = 0;
104         u32 table_size = 0;
105         struct il3945_tpt_entry *tpt_table = NULL;
106
107         if (rssi < IL_MIN_RSSI_VAL || rssi > IL_MAX_RSSI_VAL)
108                 rssi = IL_MIN_RSSI_VAL;
109
110         switch (band) {
111         case IEEE80211_BAND_2GHZ:
112                 tpt_table = il3945_tpt_table_g;
113                 table_size = ARRAY_SIZE(il3945_tpt_table_g);
114                 break;
115         case IEEE80211_BAND_5GHZ:
116                 tpt_table = il3945_tpt_table_a;
117                 table_size = ARRAY_SIZE(il3945_tpt_table_a);
118                 break;
119         default:
120                 BUG();
121                 break;
122         }
123
124         while (idx < table_size && rssi < tpt_table[idx].min_rssi)
125                 idx++;
126
127         idx = min(idx, table_size - 1);
128
129         return tpt_table[idx].idx;
130 }
131
132 static void
133 il3945_clear_win(struct il3945_rate_scale_data *win)
134 {
135         win->data = 0;
136         win->success_counter = 0;
137         win->success_ratio = -1;
138         win->counter = 0;
139         win->average_tpt = IL_INVALID_VALUE;
140         win->stamp = 0;
141 }
142
143 /**
144  * il3945_rate_scale_flush_wins - flush out the rate scale wins
145  *
146  * Returns the number of wins that have gathered data but were
147  * not flushed.  If there were any that were not flushed, then
148  * reschedule the rate flushing routine.
149  */
150 static int
151 il3945_rate_scale_flush_wins(struct il3945_rs_sta *rs_sta)
152 {
153         int unflushed = 0;
154         int i;
155         unsigned long flags;
156         struct il_priv *il __maybe_unused = rs_sta->il;
157
158         /*
159          * For each rate, if we have collected data on that rate
160          * and it has been more than RATE_WIN_FLUSH
161          * since we flushed, clear out the gathered stats
162          */
163         for (i = 0; i < RATE_COUNT_3945; i++) {
164                 if (!rs_sta->win[i].counter)
165                         continue;
166
167                 spin_lock_irqsave(&rs_sta->lock, flags);
168                 if (time_after(jiffies, rs_sta->win[i].stamp + RATE_WIN_FLUSH)) {
169                         D_RATE("flushing %d samples of rate " "idx %d\n",
170                                rs_sta->win[i].counter, i);
171                         il3945_clear_win(&rs_sta->win[i]);
172                 } else
173                         unflushed++;
174                 spin_unlock_irqrestore(&rs_sta->lock, flags);
175         }
176
177         return unflushed;
178 }
179
180 #define RATE_FLUSH_MAX              5000        /* msec */
181 #define RATE_FLUSH_MIN              50  /* msec */
182 #define IL_AVERAGE_PACKETS             1500
183
184 static void
185 il3945_bg_rate_scale_flush(unsigned long data)
186 {
187         struct il3945_rs_sta *rs_sta = (void *)data;
188         struct il_priv *il __maybe_unused = rs_sta->il;
189         int unflushed = 0;
190         unsigned long flags;
191         u32 packet_count, duration, pps;
192
193         D_RATE("enter\n");
194
195         unflushed = il3945_rate_scale_flush_wins(rs_sta);
196
197         spin_lock_irqsave(&rs_sta->lock, flags);
198
199         /* Number of packets Rx'd since last time this timer ran */
200         packet_count = (rs_sta->tx_packets - rs_sta->last_tx_packets) + 1;
201
202         rs_sta->last_tx_packets = rs_sta->tx_packets + 1;
203
204         if (unflushed) {
205                 duration =
206                     jiffies_to_msecs(jiffies - rs_sta->last_partial_flush);
207
208                 D_RATE("Tx'd %d packets in %dms\n", packet_count, duration);
209
210                 /* Determine packets per second */
211                 if (duration)
212                         pps = (packet_count * 1000) / duration;
213                 else
214                         pps = 0;
215
216                 if (pps) {
217                         duration = (IL_AVERAGE_PACKETS * 1000) / pps;
218                         if (duration < RATE_FLUSH_MIN)
219                                 duration = RATE_FLUSH_MIN;
220                         else if (duration > RATE_FLUSH_MAX)
221                                 duration = RATE_FLUSH_MAX;
222                 } else
223                         duration = RATE_FLUSH_MAX;
224
225                 rs_sta->flush_time = msecs_to_jiffies(duration);
226
227                 D_RATE("new flush period: %d msec ave %d\n", duration,
228                        packet_count);
229
230                 mod_timer(&rs_sta->rate_scale_flush,
231                           jiffies + rs_sta->flush_time);
232
233                 rs_sta->last_partial_flush = jiffies;
234         } else {
235                 rs_sta->flush_time = RATE_FLUSH;
236                 rs_sta->flush_pending = 0;
237         }
238         /* If there weren't any unflushed entries, we don't schedule the timer
239          * to run again */
240
241         rs_sta->last_flush = jiffies;
242
243         spin_unlock_irqrestore(&rs_sta->lock, flags);
244
245         D_RATE("leave\n");
246 }
247
248 /**
249  * il3945_collect_tx_data - Update the success/failure sliding win
250  *
251  * We keep a sliding win of the last 64 packets transmitted
252  * at this rate.  win->data contains the bitmask of successful
253  * packets.
254  */
255 static void
256 il3945_collect_tx_data(struct il3945_rs_sta *rs_sta,
257                        struct il3945_rate_scale_data *win, int success,
258                        int retries, int idx)
259 {
260         unsigned long flags;
261         s32 fail_count;
262         struct il_priv *il __maybe_unused = rs_sta->il;
263
264         if (!retries) {
265                 D_RATE("leave: retries == 0 -- should be at least 1\n");
266                 return;
267         }
268
269         spin_lock_irqsave(&rs_sta->lock, flags);
270
271         /*
272          * Keep track of only the latest 62 tx frame attempts in this rate's
273          * history win; anything older isn't really relevant any more.
274          * If we have filled up the sliding win, drop the oldest attempt;
275          * if the oldest attempt (highest bit in bitmap) shows "success",
276          * subtract "1" from the success counter (this is the main reason
277          * we keep these bitmaps!).
278          * */
279         while (retries > 0) {
280                 if (win->counter >= RATE_MAX_WINDOW) {
281
282                         /* remove earliest */
283                         win->counter = RATE_MAX_WINDOW - 1;
284
285                         if (win->data & (1ULL << (RATE_MAX_WINDOW - 1))) {
286                                 win->data &= ~(1ULL << (RATE_MAX_WINDOW - 1));
287                                 win->success_counter--;
288                         }
289                 }
290
291                 /* Increment frames-attempted counter */
292                 win->counter++;
293
294                 /* Shift bitmap by one frame (throw away oldest history),
295                  * OR in "1", and increment "success" if this
296                  * frame was successful. */
297                 win->data <<= 1;
298                 if (success > 0) {
299                         win->success_counter++;
300                         win->data |= 0x1;
301                         success--;
302                 }
303
304                 retries--;
305         }
306
307         /* Calculate current success ratio, avoid divide-by-0! */
308         if (win->counter > 0)
309                 win->success_ratio =
310                     128 * (100 * win->success_counter) / win->counter;
311         else
312                 win->success_ratio = IL_INVALID_VALUE;
313
314         fail_count = win->counter - win->success_counter;
315
316         /* Calculate average throughput, if we have enough history. */
317         if (fail_count >= RATE_MIN_FAILURE_TH ||
318             win->success_counter >= RATE_MIN_SUCCESS_TH)
319                 win->average_tpt =
320                     ((win->success_ratio * rs_sta->expected_tpt[idx] +
321                       64) / 128);
322         else
323                 win->average_tpt = IL_INVALID_VALUE;
324
325         /* Tag this win as having been updated */
326         win->stamp = jiffies;
327
328         spin_unlock_irqrestore(&rs_sta->lock, flags);
329 }
330
331 /*
332  * Called after adding a new station to initialize rate scaling
333  */
334 void
335 il3945_rs_rate_init(struct il_priv *il, struct ieee80211_sta *sta, u8 sta_id)
336 {
337         struct ieee80211_hw *hw = il->hw;
338         struct ieee80211_conf *conf = &il->hw->conf;
339         struct il3945_sta_priv *psta;
340         struct il3945_rs_sta *rs_sta;
341         struct ieee80211_supported_band *sband;
342         int i;
343
344         D_INFO("enter\n");
345         if (sta_id == il->hw_params.bcast_id)
346                 goto out;
347
348         psta = (struct il3945_sta_priv *)sta->drv_priv;
349         rs_sta = &psta->rs_sta;
350         sband = hw->wiphy->bands[conf->channel->band];
351
352         rs_sta->il = il;
353
354         rs_sta->start_rate = RATE_INVALID;
355
356         /* default to just 802.11b */
357         rs_sta->expected_tpt = il3945_expected_tpt_b;
358
359         rs_sta->last_partial_flush = jiffies;
360         rs_sta->last_flush = jiffies;
361         rs_sta->flush_time = RATE_FLUSH;
362         rs_sta->last_tx_packets = 0;
363
364         rs_sta->rate_scale_flush.data = (unsigned long)rs_sta;
365         rs_sta->rate_scale_flush.function = il3945_bg_rate_scale_flush;
366
367         for (i = 0; i < RATE_COUNT_3945; i++)
368                 il3945_clear_win(&rs_sta->win[i]);
369
370         /* TODO: what is a good starting rate for STA? About middle? Maybe not
371          * the lowest or the highest rate.. Could consider using RSSI from
372          * previous packets? Need to have IEEE 802.1X auth succeed immediately
373          * after assoc.. */
374
375         for (i = sband->n_bitrates - 1; i >= 0; i--) {
376                 if (sta->supp_rates[sband->band] & (1 << i)) {
377                         rs_sta->last_txrate_idx = i;
378                         break;
379                 }
380         }
381
382         il->_3945.sta_supp_rates = sta->supp_rates[sband->band];
383         /* For 5 GHz band it start at IL_FIRST_OFDM_RATE */
384         if (sband->band == IEEE80211_BAND_5GHZ) {
385                 rs_sta->last_txrate_idx += IL_FIRST_OFDM_RATE;
386                 il->_3945.sta_supp_rates <<= IL_FIRST_OFDM_RATE;
387         }
388
389 out:
390         il->stations[sta_id].used &= ~IL_STA_UCODE_INPROGRESS;
391
392         D_INFO("leave\n");
393 }
394
395 static void *
396 il3945_rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
397 {
398         return hw->priv;
399 }
400
401 /* rate scale requires free function to be implemented */
402 static void
403 il3945_rs_free(void *il)
404 {
405 }
406
407 static void *
408 il3945_rs_alloc_sta(void *il_priv, struct ieee80211_sta *sta, gfp_t gfp)
409 {
410         struct il3945_rs_sta *rs_sta;
411         struct il3945_sta_priv *psta = (void *)sta->drv_priv;
412         struct il_priv *il __maybe_unused = il_priv;
413
414         D_RATE("enter\n");
415
416         rs_sta = &psta->rs_sta;
417
418         spin_lock_init(&rs_sta->lock);
419         init_timer(&rs_sta->rate_scale_flush);
420
421         D_RATE("leave\n");
422
423         return rs_sta;
424 }
425
426 static void
427 il3945_rs_free_sta(void *il_priv, struct ieee80211_sta *sta, void *il_sta)
428 {
429         struct il3945_rs_sta *rs_sta = il_sta;
430
431         /*
432          * Be careful not to use any members of il3945_rs_sta (like trying
433          * to use il_priv to print out debugging) since it may not be fully
434          * initialized at this point.
435          */
436         del_timer_sync(&rs_sta->rate_scale_flush);
437 }
438
439 /**
440  * il3945_rs_tx_status - Update rate control values based on Tx results
441  *
442  * NOTE: Uses il_priv->retry_rate for the # of retries attempted by
443  * the hardware for each rate.
444  */
445 static void
446 il3945_rs_tx_status(void *il_rate, struct ieee80211_supported_band *sband,
447                     struct ieee80211_sta *sta, void *il_sta,
448                     struct sk_buff *skb)
449 {
450         s8 retries = 0, current_count;
451         int scale_rate_idx, first_idx, last_idx;
452         unsigned long flags;
453         struct il_priv *il = (struct il_priv *)il_rate;
454         struct il3945_rs_sta *rs_sta = il_sta;
455         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
456
457         D_RATE("enter\n");
458
459         retries = info->status.rates[0].count;
460         /* Sanity Check for retries */
461         if (retries > RATE_RETRY_TH)
462                 retries = RATE_RETRY_TH;
463
464         first_idx = sband->bitrates[info->status.rates[0].idx].hw_value;
465         if (first_idx < 0 || first_idx >= RATE_COUNT_3945) {
466                 D_RATE("leave: Rate out of bounds: %d\n", first_idx);
467                 return;
468         }
469
470         if (!il_sta) {
471                 D_RATE("leave: No STA il data to update!\n");
472                 return;
473         }
474
475         /* Treat uninitialized rate scaling data same as non-existing. */
476         if (!rs_sta->il) {
477                 D_RATE("leave: STA il data uninitialized!\n");
478                 return;
479         }
480
481         rs_sta->tx_packets++;
482
483         scale_rate_idx = first_idx;
484         last_idx = first_idx;
485
486         /*
487          * Update the win for each rate.  We determine which rates
488          * were Tx'd based on the total number of retries vs. the number
489          * of retries configured for each rate -- currently set to the
490          * il value 'retry_rate' vs. rate specific
491          *
492          * On exit from this while loop last_idx indicates the rate
493          * at which the frame was finally transmitted (or failed if no
494          * ACK)
495          */
496         while (retries > 1) {
497                 if ((retries - 1) < il->retry_rate) {
498                         current_count = (retries - 1);
499                         last_idx = scale_rate_idx;
500                 } else {
501                         current_count = il->retry_rate;
502                         last_idx = il3945_rs_next_rate(il, scale_rate_idx);
503                 }
504
505                 /* Update this rate accounting for as many retries
506                  * as was used for it (per current_count) */
507                 il3945_collect_tx_data(rs_sta, &rs_sta->win[scale_rate_idx], 0,
508                                        current_count, scale_rate_idx);
509                 D_RATE("Update rate %d for %d retries.\n", scale_rate_idx,
510                        current_count);
511
512                 retries -= current_count;
513
514                 scale_rate_idx = last_idx;
515         }
516
517         /* Update the last idx win with success/failure based on ACK */
518         D_RATE("Update rate %d with %s.\n", last_idx,
519                (info->flags & IEEE80211_TX_STAT_ACK) ? "success" : "failure");
520         il3945_collect_tx_data(rs_sta, &rs_sta->win[last_idx],
521                                info->flags & IEEE80211_TX_STAT_ACK, 1,
522                                last_idx);
523
524         /* We updated the rate scale win -- if its been more than
525          * flush_time since the last run, schedule the flush
526          * again */
527         spin_lock_irqsave(&rs_sta->lock, flags);
528
529         if (!rs_sta->flush_pending &&
530             time_after(jiffies, rs_sta->last_flush + 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         D_RATE("leave\n");
541 }
542
543 static u16
544 il3945_get_adjacent_rate(struct il3945_rs_sta *rs_sta, u8 idx, u16 rate_mask,
545                          enum ieee80211_band band)
546 {
547         u8 high = RATE_INVALID;
548         u8 low = RATE_INVALID;
549         struct il_priv *il __maybe_unused = rs_sta->il;
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 = idx - 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 = idx + 1;
568                 for (mask = (1 << i); i < RATE_COUNT_3945; 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 = idx;
579         while (low != RATE_INVALID) {
580                 if (rs_sta->tgg)
581                         low = il3945_rates[low].prev_rs_tgg;
582                 else
583                         low = il3945_rates[low].prev_rs;
584                 if (low == RATE_INVALID)
585                         break;
586                 if (rate_mask & (1 << low))
587                         break;
588                 D_RATE("Skipping masked lower rate: %d\n", low);
589         }
590
591         high = idx;
592         while (high != RATE_INVALID) {
593                 if (rs_sta->tgg)
594                         high = il3945_rates[high].next_rs_tgg;
595                 else
596                         high = il3945_rates[high].next_rs;
597                 if (high == RATE_INVALID)
598                         break;
599                 if (rate_mask & (1 << high))
600                         break;
601                 D_RATE("Skipping masked higher rate: %d\n", high);
602         }
603
604         return (high << 8) | low;
605 }
606
607 /**
608  * il3945_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 idx obtained below into the hw_mode's
620  * rate table and must reference the driver allocated rate table
621  *
622  */
623 static void
624 il3945_rs_get_rate(void *il_r, struct ieee80211_sta *sta, void *il_sta,
625                    struct ieee80211_tx_rate_control *txrc)
626 {
627         struct ieee80211_supported_band *sband = txrc->sband;
628         struct sk_buff *skb = txrc->skb;
629         u8 low = RATE_INVALID;
630         u8 high = RATE_INVALID;
631         u16 high_low;
632         int idx;
633         struct il3945_rs_sta *rs_sta = il_sta;
634         struct il3945_rate_scale_data *win = NULL;
635         int current_tpt = IL_INVALID_VALUE;
636         int low_tpt = IL_INVALID_VALUE;
637         int high_tpt = IL_INVALID_VALUE;
638         u32 fail_count;
639         s8 scale_action = 0;
640         unsigned long flags;
641         u16 rate_mask;
642         s8 max_rate_idx = -1;
643         struct il_priv *il __maybe_unused = (struct il_priv *)il_r;
644         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
645
646         D_RATE("enter\n");
647
648         /* Treat uninitialized rate scaling data same as non-existing. */
649         if (rs_sta && !rs_sta->il) {
650                 D_RATE("Rate scaling information not initialized yet.\n");
651                 il_sta = NULL;
652         }
653
654         if (rate_control_send_low(sta, il_sta, txrc))
655                 return;
656
657         rate_mask = sta->supp_rates[sband->band];
658
659         /* get user max rate if set */
660         max_rate_idx = txrc->max_rate_idx;
661         if (sband->band == IEEE80211_BAND_5GHZ && max_rate_idx != -1)
662                 max_rate_idx += IL_FIRST_OFDM_RATE;
663         if (max_rate_idx < 0 || max_rate_idx >= RATE_COUNT)
664                 max_rate_idx = -1;
665
666         idx = min(rs_sta->last_txrate_idx & 0xffff, RATE_COUNT_3945 - 1);
667
668         if (sband->band == IEEE80211_BAND_5GHZ)
669                 rate_mask = rate_mask << IL_FIRST_OFDM_RATE;
670
671         spin_lock_irqsave(&rs_sta->lock, flags);
672
673         /* for recent assoc, choose best rate regarding
674          * to rssi value
675          */
676         if (rs_sta->start_rate != RATE_INVALID) {
677                 if (rs_sta->start_rate < idx &&
678                     (rate_mask & (1 << rs_sta->start_rate)))
679                         idx = rs_sta->start_rate;
680                 rs_sta->start_rate = RATE_INVALID;
681         }
682
683         /* force user max rate if set by user */
684         if (max_rate_idx != -1 && max_rate_idx < idx) {
685                 if (rate_mask & (1 << max_rate_idx))
686                         idx = max_rate_idx;
687         }
688
689         win = &(rs_sta->win[idx]);
690
691         fail_count = win->counter - win->success_counter;
692
693         if (fail_count < RATE_MIN_FAILURE_TH &&
694             win->success_counter < RATE_MIN_SUCCESS_TH) {
695                 spin_unlock_irqrestore(&rs_sta->lock, flags);
696
697                 D_RATE("Invalid average_tpt on rate %d: "
698                        "counter: %d, success_counter: %d, "
699                        "expected_tpt is %sNULL\n", idx, win->counter,
700                        win->success_counter,
701                        rs_sta->expected_tpt ? "not " : "");
702
703                 /* Can't calculate this yet; not enough history */
704                 win->average_tpt = IL_INVALID_VALUE;
705                 goto out;
706
707         }
708
709         current_tpt = win->average_tpt;
710
711         high_low =
712             il3945_get_adjacent_rate(rs_sta, idx, rate_mask, sband->band);
713         low = high_low & 0xff;
714         high = (high_low >> 8) & 0xff;
715
716         /* If user set max rate, dont allow higher than user constrain */
717         if (max_rate_idx != -1 && max_rate_idx < high)
718                 high = RATE_INVALID;
719
720         /* Collect Measured throughputs of adjacent rates */
721         if (low != RATE_INVALID)
722                 low_tpt = rs_sta->win[low].average_tpt;
723
724         if (high != RATE_INVALID)
725                 high_tpt = rs_sta->win[high].average_tpt;
726
727         spin_unlock_irqrestore(&rs_sta->lock, flags);
728
729         scale_action = 0;
730
731         /* Low success ratio , need to drop the rate */
732         if (win->success_ratio < RATE_DECREASE_TH || !current_tpt) {
733                 D_RATE("decrease rate because of low success_ratio\n");
734                 scale_action = -1;
735                 /* No throughput measured yet for adjacent rates,
736                  * try increase */
737         } else if (low_tpt == IL_INVALID_VALUE && high_tpt == IL_INVALID_VALUE) {
738
739                 if (high != RATE_INVALID &&
740                     win->success_ratio >= RATE_INCREASE_TH)
741                         scale_action = 1;
742                 else if (low != RATE_INVALID)
743                         scale_action = 0;
744
745                 /* Both adjacent throughputs are measured, but neither one has
746                  * better throughput; we're using the best rate, don't change
747                  * it! */
748         } else if (low_tpt != IL_INVALID_VALUE && high_tpt != IL_INVALID_VALUE
749                    && low_tpt < current_tpt && high_tpt < current_tpt) {
750
751                 D_RATE("No action -- low [%d] & high [%d] < "
752                        "current_tpt [%d]\n", low_tpt, high_tpt, current_tpt);
753                 scale_action = 0;
754
755                 /* At least one of the rates has better throughput */
756         } else {
757                 if (high_tpt != IL_INVALID_VALUE) {
758
759                         /* High rate has better throughput, Increase
760                          * rate */
761                         if (high_tpt > current_tpt &&
762                             win->success_ratio >= RATE_INCREASE_TH)
763                                 scale_action = 1;
764                         else {
765                                 D_RATE("decrease rate because of high tpt\n");
766                                 scale_action = 0;
767                         }
768                 } else if (low_tpt != IL_INVALID_VALUE) {
769                         if (low_tpt > current_tpt) {
770                                 D_RATE("decrease rate because of low tpt\n");
771                                 scale_action = -1;
772                         } else if (win->success_ratio >= RATE_INCREASE_TH) {
773                                 /* Lower rate has better
774                                  * throughput,decrease rate */
775                                 scale_action = 1;
776                         }
777                 }
778         }
779
780         /* Sanity check; asked for decrease, but success rate or throughput
781          * has been good at old rate.  Don't change it. */
782         if (scale_action == -1 && low != RATE_INVALID &&
783             (win->success_ratio > RATE_HIGH_TH ||
784              current_tpt > 100 * rs_sta->expected_tpt[low]))
785                 scale_action = 0;
786
787         switch (scale_action) {
788         case -1:
789                 /* Decrese rate */
790                 if (low != RATE_INVALID)
791                         idx = low;
792                 break;
793         case 1:
794                 /* Increase rate */
795                 if (high != RATE_INVALID)
796                         idx = high;
797
798                 break;
799         case 0:
800         default:
801                 /* No change */
802                 break;
803         }
804
805         D_RATE("Selected %d (action %d) - low %d high %d\n", idx, scale_action,
806                low, high);
807
808 out:
809
810         if (sband->band == IEEE80211_BAND_5GHZ) {
811                 if (WARN_ON_ONCE(idx < IL_FIRST_OFDM_RATE))
812                         idx = IL_FIRST_OFDM_RATE;
813                 rs_sta->last_txrate_idx = idx;
814                 info->control.rates[0].idx = idx - IL_FIRST_OFDM_RATE;
815         } else {
816                 rs_sta->last_txrate_idx = idx;
817                 info->control.rates[0].idx = rs_sta->last_txrate_idx;
818         }
819
820         D_RATE("leave: %d\n", idx);
821 }
822
823 #ifdef CONFIG_MAC80211_DEBUGFS
824 static int
825 il3945_open_file_generic(struct inode *inode, struct file *file)
826 {
827         file->private_data = inode->i_private;
828         return 0;
829 }
830
831 static ssize_t
832 il3945_sta_dbgfs_stats_table_read(struct file *file, char __user *user_buf,
833                                   size_t count, loff_t *ppos)
834 {
835         char *buff;
836         int desc = 0;
837         int j;
838         ssize_t ret;
839         struct il3945_rs_sta *lq_sta = file->private_data;
840
841         buff = kmalloc(1024, GFP_KERNEL);
842         if (!buff)
843                 return -ENOMEM;
844
845         desc +=
846             sprintf(buff + desc,
847                     "tx packets=%d last rate idx=%d\n"
848                     "rate=0x%X flush time %d\n", lq_sta->tx_packets,
849                     lq_sta->last_txrate_idx, lq_sta->start_rate,
850                     jiffies_to_msecs(lq_sta->flush_time));
851         for (j = 0; j < RATE_COUNT_3945; j++) {
852                 desc +=
853                     sprintf(buff + desc, "counter=%d success=%d %%=%d\n",
854                             lq_sta->win[j].counter,
855                             lq_sta->win[j].success_counter,
856                             lq_sta->win[j].success_ratio);
857         }
858         ret = simple_read_from_buffer(user_buf, count, ppos, buff, desc);
859         kfree(buff);
860         return ret;
861 }
862
863 static const struct file_operations rs_sta_dbgfs_stats_table_ops = {
864         .read = il3945_sta_dbgfs_stats_table_read,
865         .open = il3945_open_file_generic,
866         .llseek = default_llseek,
867 };
868
869 static void
870 il3945_add_debugfs(void *il, void *il_sta, struct dentry *dir)
871 {
872         struct il3945_rs_sta *lq_sta = il_sta;
873
874         lq_sta->rs_sta_dbgfs_stats_table_file =
875             debugfs_create_file("rate_stats_table", 0600, dir, lq_sta,
876                                 &rs_sta_dbgfs_stats_table_ops);
877
878 }
879
880 static void
881 il3945_remove_debugfs(void *il, void *il_sta)
882 {
883         struct il3945_rs_sta *lq_sta = il_sta;
884         debugfs_remove(lq_sta->rs_sta_dbgfs_stats_table_file);
885 }
886 #endif
887
888 /*
889  * Initialization of rate scaling information is done by driver after
890  * the station is added. Since mac80211 calls this function before a
891  * station is added we ignore it.
892  */
893 static void
894 il3945_rs_rate_init_stub(void *il_r, struct ieee80211_supported_band *sband,
895                          struct ieee80211_sta *sta, void *il_sta)
896 {
897 }
898
899 static struct rate_control_ops rs_ops = {
900         .module = NULL,
901         .name = RS_NAME,
902         .tx_status = il3945_rs_tx_status,
903         .get_rate = il3945_rs_get_rate,
904         .rate_init = il3945_rs_rate_init_stub,
905         .alloc = il3945_rs_alloc,
906         .free = il3945_rs_free,
907         .alloc_sta = il3945_rs_alloc_sta,
908         .free_sta = il3945_rs_free_sta,
909 #ifdef CONFIG_MAC80211_DEBUGFS
910         .add_sta_debugfs = il3945_add_debugfs,
911         .remove_sta_debugfs = il3945_remove_debugfs,
912 #endif
913
914 };
915
916 void
917 il3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
918 {
919         struct il_priv *il = hw->priv;
920         s32 rssi = 0;
921         unsigned long flags;
922         struct il3945_rs_sta *rs_sta;
923         struct ieee80211_sta *sta;
924         struct il3945_sta_priv *psta;
925
926         D_RATE("enter\n");
927
928         rcu_read_lock();
929
930         sta = ieee80211_find_sta(il->vif, il->stations[sta_id].sta.sta.addr);
931         if (!sta) {
932                 D_RATE("Unable to find station to initialize rate scaling.\n");
933                 rcu_read_unlock();
934                 return;
935         }
936
937         psta = (void *)sta->drv_priv;
938         rs_sta = &psta->rs_sta;
939
940         spin_lock_irqsave(&rs_sta->lock, flags);
941
942         rs_sta->tgg = 0;
943         switch (il->band) {
944         case IEEE80211_BAND_2GHZ:
945                 /* TODO: this always does G, not a regression */
946                 if (il->active.flags & RXON_FLG_TGG_PROTECT_MSK) {
947                         rs_sta->tgg = 1;
948                         rs_sta->expected_tpt = il3945_expected_tpt_g_prot;
949                 } else
950                         rs_sta->expected_tpt = il3945_expected_tpt_g;
951                 break;
952         case IEEE80211_BAND_5GHZ:
953                 rs_sta->expected_tpt = il3945_expected_tpt_a;
954                 break;
955         case IEEE80211_NUM_BANDS:
956                 BUG();
957                 break;
958         }
959
960         spin_unlock_irqrestore(&rs_sta->lock, flags);
961
962         rssi = il->_3945.last_rx_rssi;
963         if (rssi == 0)
964                 rssi = IL_MIN_RSSI_VAL;
965
966         D_RATE("Network RSSI: %d\n", rssi);
967
968         rs_sta->start_rate = il3945_get_rate_idx_by_rssi(rssi, il->band);
969
970         D_RATE("leave: rssi %d assign rate idx: " "%d (plcp 0x%x)\n", rssi,
971                rs_sta->start_rate, il3945_rates[rs_sta->start_rate].plcp);
972         rcu_read_unlock();
973 }
974
975 int
976 il3945_rate_control_register(void)
977 {
978         return ieee80211_rate_control_register(&rs_ops);
979 }
980
981 void
982 il3945_rate_control_unregister(void)
983 {
984         ieee80211_rate_control_unregister(&rs_ops);
985 }