1 // SPDX-License-Identifier: GPL-2.0-only
2 /******************************************************************************
3  *
4  * Copyright(c) 2005 - 2011 Intel Corporation. All rights reserved.
5  *
6  * Contact Information:
7  *  Intel Linux Wireless <ilw@linux.intel.com>
8  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
9  *
10  *****************************************************************************/
11 
12 #include <linux/kernel.h>
13 #include <linux/skbuff.h>
14 #include <linux/slab.h>
15 #include <net/mac80211.h>
16 
17 #include <linux/netdevice.h>
18 #include <linux/etherdevice.h>
19 #include <linux/delay.h>
20 
21 #include <linux/workqueue.h>
22 
23 #include "commands.h"
24 #include "3945.h"
25 
26 #define RS_NAME "iwl-3945-rs"
27 
28 static s32 il3945_expected_tpt_g[RATE_COUNT_3945] = {
29 	7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
30 };
31 
32 static s32 il3945_expected_tpt_g_prot[RATE_COUNT_3945] = {
33 	7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
34 };
35 
36 static s32 il3945_expected_tpt_a[RATE_COUNT_3945] = {
37 	0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186
38 };
39 
40 static s32 il3945_expected_tpt_b[RATE_COUNT_3945] = {
41 	7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
42 };
43 
44 struct il3945_tpt_entry {
45 	s8 min_rssi;
46 	u8 idx;
47 };
48 
49 static struct il3945_tpt_entry il3945_tpt_table_a[] = {
50 	{-60, RATE_54M_IDX},
51 	{-64, RATE_48M_IDX},
52 	{-72, RATE_36M_IDX},
53 	{-80, RATE_24M_IDX},
54 	{-84, RATE_18M_IDX},
55 	{-85, RATE_12M_IDX},
56 	{-87, RATE_9M_IDX},
57 	{-89, RATE_6M_IDX}
58 };
59 
60 static struct il3945_tpt_entry il3945_tpt_table_g[] = {
61 	{-60, RATE_54M_IDX},
62 	{-64, RATE_48M_IDX},
63 	{-68, RATE_36M_IDX},
64 	{-80, RATE_24M_IDX},
65 	{-84, RATE_18M_IDX},
66 	{-85, RATE_12M_IDX},
67 	{-86, RATE_11M_IDX},
68 	{-88, RATE_5M_IDX},
69 	{-90, RATE_2M_IDX},
70 	{-92, RATE_1M_IDX}
71 };
72 
73 #define RATE_MAX_WINDOW		62
74 #define RATE_FLUSH		(3*HZ)
75 #define RATE_WIN_FLUSH		(HZ/2)
76 #define IL39_RATE_HIGH_TH	11520
77 #define IL_SUCCESS_UP_TH	8960
78 #define IL_SUCCESS_DOWN_TH	10880
79 #define RATE_MIN_FAILURE_TH	6
80 #define RATE_MIN_SUCCESS_TH	8
81 #define RATE_DECREASE_TH	1920
82 #define RATE_RETRY_TH		15
83 
84 static u8
85 il3945_get_rate_idx_by_rssi(s32 rssi, enum nl80211_band band)
86 {
87 	u32 idx = 0;
88 	u32 table_size = 0;
89 	struct il3945_tpt_entry *tpt_table = NULL;
90 
91 	if (rssi < IL_MIN_RSSI_VAL || rssi > IL_MAX_RSSI_VAL)
92 		rssi = IL_MIN_RSSI_VAL;
93 
94 	switch (band) {
95 	case NL80211_BAND_2GHZ:
96 		tpt_table = il3945_tpt_table_g;
97 		table_size = ARRAY_SIZE(il3945_tpt_table_g);
98 		break;
99 	case NL80211_BAND_5GHZ:
100 		tpt_table = il3945_tpt_table_a;
101 		table_size = ARRAY_SIZE(il3945_tpt_table_a);
102 		break;
103 	default:
104 		BUG();
105 		break;
106 	}
107 
108 	while (idx < table_size && rssi < tpt_table[idx].min_rssi)
109 		idx++;
110 
111 	idx = min(idx, table_size - 1);
112 
113 	return tpt_table[idx].idx;
114 }
115 
116 static void
117 il3945_clear_win(struct il3945_rate_scale_data *win)
118 {
119 	win->data = 0;
120 	win->success_counter = 0;
121 	win->success_ratio = -1;
122 	win->counter = 0;
123 	win->average_tpt = IL_INVALID_VALUE;
124 	win->stamp = 0;
125 }
126 
127 /**
128  * il3945_rate_scale_flush_wins - flush out the rate scale wins
129  *
130  * Returns the number of wins that have gathered data but were
131  * not flushed.  If there were any that were not flushed, then
132  * reschedule the rate flushing routine.
133  */
134 static int
135 il3945_rate_scale_flush_wins(struct il3945_rs_sta *rs_sta)
136 {
137 	int unflushed = 0;
138 	int i;
139 	unsigned long flags;
140 	struct il_priv *il __maybe_unused = rs_sta->il;
141 
142 	/*
143 	 * For each rate, if we have collected data on that rate
144 	 * and it has been more than RATE_WIN_FLUSH
145 	 * since we flushed, clear out the gathered stats
146 	 */
147 	for (i = 0; i < RATE_COUNT_3945; i++) {
148 		if (!rs_sta->win[i].counter)
149 			continue;
150 
151 		spin_lock_irqsave(&rs_sta->lock, flags);
152 		if (time_after(jiffies, rs_sta->win[i].stamp + RATE_WIN_FLUSH)) {
153 			D_RATE("flushing %d samples of rate " "idx %d\n",
154 			       rs_sta->win[i].counter, i);
155 			il3945_clear_win(&rs_sta->win[i]);
156 		} else
157 			unflushed++;
158 		spin_unlock_irqrestore(&rs_sta->lock, flags);
159 	}
160 
161 	return unflushed;
162 }
163 
164 #define RATE_FLUSH_MAX              5000	/* msec */
165 #define RATE_FLUSH_MIN              50	/* msec */
166 #define IL_AVERAGE_PACKETS             1500
167 
168 static void
169 il3945_bg_rate_scale_flush(struct timer_list *t)
170 {
171 	struct il3945_rs_sta *rs_sta = from_timer(rs_sta, t, rate_scale_flush);
172 	struct il_priv *il __maybe_unused = rs_sta->il;
173 	int unflushed = 0;
174 	unsigned long flags;
175 	u32 packet_count, duration, pps;
176 
177 	D_RATE("enter\n");
178 
179 	unflushed = il3945_rate_scale_flush_wins(rs_sta);
180 
181 	spin_lock_irqsave(&rs_sta->lock, flags);
182 
183 	/* Number of packets Rx'd since last time this timer ran */
184 	packet_count = (rs_sta->tx_packets - rs_sta->last_tx_packets) + 1;
185 
186 	rs_sta->last_tx_packets = rs_sta->tx_packets + 1;
187 
188 	if (unflushed) {
189 		duration =
190 		    jiffies_to_msecs(jiffies - rs_sta->last_partial_flush);
191 
192 		D_RATE("Tx'd %d packets in %dms\n", packet_count, duration);
193 
194 		/* Determine packets per second */
195 		if (duration)
196 			pps = (packet_count * 1000) / duration;
197 		else
198 			pps = 0;
199 
200 		if (pps) {
201 			duration = (IL_AVERAGE_PACKETS * 1000) / pps;
202 			if (duration < RATE_FLUSH_MIN)
203 				duration = RATE_FLUSH_MIN;
204 			else if (duration > RATE_FLUSH_MAX)
205 				duration = RATE_FLUSH_MAX;
206 		} else
207 			duration = RATE_FLUSH_MAX;
208 
209 		rs_sta->flush_time = msecs_to_jiffies(duration);
210 
211 		D_RATE("new flush period: %d msec ave %d\n", duration,
212 		       packet_count);
213 
214 		mod_timer(&rs_sta->rate_scale_flush,
215 			  jiffies + rs_sta->flush_time);
216 
217 		rs_sta->last_partial_flush = jiffies;
218 	} else {
219 		rs_sta->flush_time = RATE_FLUSH;
220 		rs_sta->flush_pending = 0;
221 	}
222 	/* If there weren't any unflushed entries, we don't schedule the timer
223 	 * to run again */
224 
225 	rs_sta->last_flush = jiffies;
226 
227 	spin_unlock_irqrestore(&rs_sta->lock, flags);
228 
229 	D_RATE("leave\n");
230 }
231 
232 /**
233  * il3945_collect_tx_data - Update the success/failure sliding win
234  *
235  * We keep a sliding win of the last 64 packets transmitted
236  * at this rate.  win->data contains the bitmask of successful
237  * packets.
238  */
239 static void
240 il3945_collect_tx_data(struct il3945_rs_sta *rs_sta,
241 		       struct il3945_rate_scale_data *win, int success,
242 		       int retries, int idx)
243 {
244 	unsigned long flags;
245 	s32 fail_count;
246 	struct il_priv *il __maybe_unused = rs_sta->il;
247 
248 	if (!retries) {
249 		D_RATE("leave: retries == 0 -- should be at least 1\n");
250 		return;
251 	}
252 
253 	spin_lock_irqsave(&rs_sta->lock, flags);
254 
255 	/*
256 	 * Keep track of only the latest 62 tx frame attempts in this rate's
257 	 * history win; anything older isn't really relevant any more.
258 	 * If we have filled up the sliding win, drop the oldest attempt;
259 	 * if the oldest attempt (highest bit in bitmap) shows "success",
260 	 * subtract "1" from the success counter (this is the main reason
261 	 * we keep these bitmaps!).
262 	 * */
263 	while (retries > 0) {
264 		if (win->counter >= RATE_MAX_WINDOW) {
265 
266 			/* remove earliest */
267 			win->counter = RATE_MAX_WINDOW - 1;
268 
269 			if (win->data & (1ULL << (RATE_MAX_WINDOW - 1))) {
270 				win->data &= ~(1ULL << (RATE_MAX_WINDOW - 1));
271 				win->success_counter--;
272 			}
273 		}
274 
275 		/* Increment frames-attempted counter */
276 		win->counter++;
277 
278 		/* Shift bitmap by one frame (throw away oldest history),
279 		 * OR in "1", and increment "success" if this
280 		 * frame was successful. */
281 		win->data <<= 1;
282 		if (success > 0) {
283 			win->success_counter++;
284 			win->data |= 0x1;
285 			success--;
286 		}
287 
288 		retries--;
289 	}
290 
291 	/* Calculate current success ratio, avoid divide-by-0! */
292 	if (win->counter > 0)
293 		win->success_ratio =
294 		    128 * (100 * win->success_counter) / win->counter;
295 	else
296 		win->success_ratio = IL_INVALID_VALUE;
297 
298 	fail_count = win->counter - win->success_counter;
299 
300 	/* Calculate average throughput, if we have enough history. */
301 	if (fail_count >= RATE_MIN_FAILURE_TH ||
302 	    win->success_counter >= RATE_MIN_SUCCESS_TH)
303 		win->average_tpt =
304 		    ((win->success_ratio * rs_sta->expected_tpt[idx] +
305 		      64) / 128);
306 	else
307 		win->average_tpt = IL_INVALID_VALUE;
308 
309 	/* Tag this win as having been updated */
310 	win->stamp = jiffies;
311 
312 	spin_unlock_irqrestore(&rs_sta->lock, flags);
313 }
314 
315 /*
316  * Called after adding a new station to initialize rate scaling
317  */
318 void
319 il3945_rs_rate_init(struct il_priv *il, struct ieee80211_sta *sta, u8 sta_id)
320 {
321 	struct ieee80211_hw *hw = il->hw;
322 	struct ieee80211_conf *conf = &il->hw->conf;
323 	struct il3945_sta_priv *psta;
324 	struct il3945_rs_sta *rs_sta;
325 	struct ieee80211_supported_band *sband;
326 	int i;
327 
328 	D_INFO("enter\n");
329 	if (sta_id == il->hw_params.bcast_id)
330 		goto out;
331 
332 	psta = (struct il3945_sta_priv *)sta->drv_priv;
333 	rs_sta = &psta->rs_sta;
334 	sband = hw->wiphy->bands[conf->chandef.chan->band];
335 
336 	rs_sta->il = il;
337 
338 	rs_sta->start_rate = RATE_INVALID;
339 
340 	/* default to just 802.11b */
341 	rs_sta->expected_tpt = il3945_expected_tpt_b;
342 
343 	rs_sta->last_partial_flush = jiffies;
344 	rs_sta->last_flush = jiffies;
345 	rs_sta->flush_time = RATE_FLUSH;
346 	rs_sta->last_tx_packets = 0;
347 
348 	for (i = 0; i < RATE_COUNT_3945; i++)
349 		il3945_clear_win(&rs_sta->win[i]);
350 
351 	/* TODO: what is a good starting rate for STA? About middle? Maybe not
352 	 * the lowest or the highest rate.. Could consider using RSSI from
353 	 * previous packets? Need to have IEEE 802.1X auth succeed immediately
354 	 * after assoc.. */
355 
356 	for (i = sband->n_bitrates - 1; i >= 0; i--) {
357 		if (sta->supp_rates[sband->band] & (1 << i)) {
358 			rs_sta->last_txrate_idx = i;
359 			break;
360 		}
361 	}
362 
363 	il->_3945.sta_supp_rates = sta->supp_rates[sband->band];
364 	/* For 5 GHz band it start at IL_FIRST_OFDM_RATE */
365 	if (sband->band == NL80211_BAND_5GHZ) {
366 		rs_sta->last_txrate_idx += IL_FIRST_OFDM_RATE;
367 		il->_3945.sta_supp_rates <<= IL_FIRST_OFDM_RATE;
368 	}
369 
370 out:
371 	il->stations[sta_id].used &= ~IL_STA_UCODE_INPROGRESS;
372 
373 	D_INFO("leave\n");
374 }
375 
376 static void *
377 il3945_rs_alloc(struct ieee80211_hw *hw)
378 {
379 	return hw->priv;
380 }
381 
382 /* rate scale requires free function to be implemented */
383 static void
384 il3945_rs_free(void *il)
385 {
386 }
387 
388 static void *
389 il3945_rs_alloc_sta(void *il_priv, struct ieee80211_sta *sta, gfp_t gfp)
390 {
391 	struct il3945_rs_sta *rs_sta;
392 	struct il3945_sta_priv *psta = (void *)sta->drv_priv;
393 	struct il_priv *il __maybe_unused = il_priv;
394 
395 	D_RATE("enter\n");
396 
397 	rs_sta = &psta->rs_sta;
398 
399 	spin_lock_init(&rs_sta->lock);
400 	timer_setup(&rs_sta->rate_scale_flush, il3945_bg_rate_scale_flush, 0);
401 	D_RATE("leave\n");
402 
403 	return rs_sta;
404 }
405 
406 static void
407 il3945_rs_free_sta(void *il_priv, struct ieee80211_sta *sta, void *il_sta)
408 {
409 	struct il3945_rs_sta *rs_sta = il_sta;
410 
411 	/*
412 	 * Be careful not to use any members of il3945_rs_sta (like trying
413 	 * to use il_priv to print out debugging) since it may not be fully
414 	 * initialized at this point.
415 	 */
416 	del_timer_sync(&rs_sta->rate_scale_flush);
417 }
418 
419 /**
420  * il3945_rs_tx_status - Update rate control values based on Tx results
421  *
422  * NOTE: Uses il_priv->retry_rate for the # of retries attempted by
423  * the hardware for each rate.
424  */
425 static void
426 il3945_rs_tx_status(void *il_rate, struct ieee80211_supported_band *sband,
427 		    struct ieee80211_sta *sta, void *il_sta,
428 		    struct sk_buff *skb)
429 {
430 	s8 retries = 0, current_count;
431 	int scale_rate_idx, first_idx, last_idx;
432 	unsigned long flags;
433 	struct il_priv *il = (struct il_priv *)il_rate;
434 	struct il3945_rs_sta *rs_sta = il_sta;
435 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
436 
437 	D_RATE("enter\n");
438 
439 	retries = info->status.rates[0].count;
440 	/* Sanity Check for retries */
441 	if (retries > RATE_RETRY_TH)
442 		retries = RATE_RETRY_TH;
443 
444 	first_idx = sband->bitrates[info->status.rates[0].idx].hw_value;
445 	if (first_idx < 0 || first_idx >= RATE_COUNT_3945) {
446 		D_RATE("leave: Rate out of bounds: %d\n", first_idx);
447 		return;
448 	}
449 
450 	if (!il_sta) {
451 		D_RATE("leave: No STA il data to update!\n");
452 		return;
453 	}
454 
455 	/* Treat uninitialized rate scaling data same as non-existing. */
456 	if (!rs_sta->il) {
457 		D_RATE("leave: STA il data uninitialized!\n");
458 		return;
459 	}
460 
461 	rs_sta->tx_packets++;
462 
463 	scale_rate_idx = first_idx;
464 	last_idx = first_idx;
465 
466 	/*
467 	 * Update the win for each rate.  We determine which rates
468 	 * were Tx'd based on the total number of retries vs. the number
469 	 * of retries configured for each rate -- currently set to the
470 	 * il value 'retry_rate' vs. rate specific
471 	 *
472 	 * On exit from this while loop last_idx indicates the rate
473 	 * at which the frame was finally transmitted (or failed if no
474 	 * ACK)
475 	 */
476 	while (retries > 1) {
477 		if ((retries - 1) < il->retry_rate) {
478 			current_count = (retries - 1);
479 			last_idx = scale_rate_idx;
480 		} else {
481 			current_count = il->retry_rate;
482 			last_idx = il3945_rs_next_rate(il, scale_rate_idx);
483 		}
484 
485 		/* Update this rate accounting for as many retries
486 		 * as was used for it (per current_count) */
487 		il3945_collect_tx_data(rs_sta, &rs_sta->win[scale_rate_idx], 0,
488 				       current_count, scale_rate_idx);
489 		D_RATE("Update rate %d for %d retries.\n", scale_rate_idx,
490 		       current_count);
491 
492 		retries -= current_count;
493 
494 		scale_rate_idx = last_idx;
495 	}
496 
497 	/* Update the last idx win with success/failure based on ACK */
498 	D_RATE("Update rate %d with %s.\n", last_idx,
499 	       (info->flags & IEEE80211_TX_STAT_ACK) ? "success" : "failure");
500 	il3945_collect_tx_data(rs_sta, &rs_sta->win[last_idx],
501 			       info->flags & IEEE80211_TX_STAT_ACK, 1,
502 			       last_idx);
503 
504 	/* We updated the rate scale win -- if its been more than
505 	 * flush_time since the last run, schedule the flush
506 	 * again */
507 	spin_lock_irqsave(&rs_sta->lock, flags);
508 
509 	if (!rs_sta->flush_pending &&
510 	    time_after(jiffies, rs_sta->last_flush + rs_sta->flush_time)) {
511 
512 		rs_sta->last_partial_flush = jiffies;
513 		rs_sta->flush_pending = 1;
514 		mod_timer(&rs_sta->rate_scale_flush,
515 			  jiffies + rs_sta->flush_time);
516 	}
517 
518 	spin_unlock_irqrestore(&rs_sta->lock, flags);
519 
520 	D_RATE("leave\n");
521 }
522 
523 static u16
524 il3945_get_adjacent_rate(struct il3945_rs_sta *rs_sta, u8 idx, u16 rate_mask,
525 			 enum nl80211_band band)
526 {
527 	u8 high = RATE_INVALID;
528 	u8 low = RATE_INVALID;
529 	struct il_priv *il __maybe_unused = rs_sta->il;
530 
531 	/* 802.11A walks to the next literal adjacent rate in
532 	 * the rate table */
533 	if (unlikely(band == NL80211_BAND_5GHZ)) {
534 		int i;
535 		u32 mask;
536 
537 		/* Find the previous rate that is in the rate mask */
538 		i = idx - 1;
539 		for (mask = (1 << i); i >= 0; i--, mask >>= 1) {
540 			if (rate_mask & mask) {
541 				low = i;
542 				break;
543 			}
544 		}
545 
546 		/* Find the next rate that is in the rate mask */
547 		i = idx + 1;
548 		for (mask = (1 << i); i < RATE_COUNT_3945; i++, mask <<= 1) {
549 			if (rate_mask & mask) {
550 				high = i;
551 				break;
552 			}
553 		}
554 
555 		return (high << 8) | low;
556 	}
557 
558 	low = idx;
559 	while (low != RATE_INVALID) {
560 		if (rs_sta->tgg)
561 			low = il3945_rates[low].prev_rs_tgg;
562 		else
563 			low = il3945_rates[low].prev_rs;
564 		if (low == RATE_INVALID)
565 			break;
566 		if (rate_mask & (1 << low))
567 			break;
568 		D_RATE("Skipping masked lower rate: %d\n", low);
569 	}
570 
571 	high = idx;
572 	while (high != RATE_INVALID) {
573 		if (rs_sta->tgg)
574 			high = il3945_rates[high].next_rs_tgg;
575 		else
576 			high = il3945_rates[high].next_rs;
577 		if (high == RATE_INVALID)
578 			break;
579 		if (rate_mask & (1 << high))
580 			break;
581 		D_RATE("Skipping masked higher rate: %d\n", high);
582 	}
583 
584 	return (high << 8) | low;
585 }
586 
587 /**
588  * il3945_rs_get_rate - find the rate for the requested packet
589  *
590  * Returns the ieee80211_rate structure allocated by the driver.
591  *
592  * The rate control algorithm has no internal mapping between hw_mode's
593  * rate ordering and the rate ordering used by the rate control algorithm.
594  *
595  * The rate control algorithm uses a single table of rates that goes across
596  * the entire A/B/G spectrum vs. being limited to just one particular
597  * hw_mode.
598  *
599  * As such, we can't convert the idx obtained below into the hw_mode's
600  * rate table and must reference the driver allocated rate table
601  *
602  */
603 static void
604 il3945_rs_get_rate(void *il_r, struct ieee80211_sta *sta, void *il_sta,
605 		   struct ieee80211_tx_rate_control *txrc)
606 {
607 	struct ieee80211_supported_band *sband = txrc->sband;
608 	struct sk_buff *skb = txrc->skb;
609 	u8 low = RATE_INVALID;
610 	u8 high = RATE_INVALID;
611 	u16 high_low;
612 	int idx;
613 	struct il3945_rs_sta *rs_sta = il_sta;
614 	struct il3945_rate_scale_data *win = NULL;
615 	int current_tpt = IL_INVALID_VALUE;
616 	int low_tpt = IL_INVALID_VALUE;
617 	int high_tpt = IL_INVALID_VALUE;
618 	u32 fail_count;
619 	s8 scale_action = 0;
620 	unsigned long flags;
621 	u16 rate_mask;
622 	s8 max_rate_idx = -1;
623 	struct il_priv *il __maybe_unused = (struct il_priv *)il_r;
624 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
625 
626 	D_RATE("enter\n");
627 
628 	/* Treat uninitialized rate scaling data same as non-existing. */
629 	if (rs_sta && !rs_sta->il) {
630 		D_RATE("Rate scaling information not initialized yet.\n");
631 		il_sta = NULL;
632 	}
633 
634 	rate_mask = sta->supp_rates[sband->band];
635 
636 	/* get user max rate if set */
637 	max_rate_idx = fls(txrc->rate_idx_mask) - 1;
638 	if (sband->band == NL80211_BAND_5GHZ && max_rate_idx != -1)
639 		max_rate_idx += IL_FIRST_OFDM_RATE;
640 	if (max_rate_idx < 0 || max_rate_idx >= RATE_COUNT)
641 		max_rate_idx = -1;
642 
643 	idx = min(rs_sta->last_txrate_idx & 0xffff, RATE_COUNT_3945 - 1);
644 
645 	if (sband->band == NL80211_BAND_5GHZ)
646 		rate_mask = rate_mask << IL_FIRST_OFDM_RATE;
647 
648 	spin_lock_irqsave(&rs_sta->lock, flags);
649 
650 	/* for recent assoc, choose best rate regarding
651 	 * to rssi value
652 	 */
653 	if (rs_sta->start_rate != RATE_INVALID) {
654 		if (rs_sta->start_rate < idx &&
655 		    (rate_mask & (1 << rs_sta->start_rate)))
656 			idx = rs_sta->start_rate;
657 		rs_sta->start_rate = RATE_INVALID;
658 	}
659 
660 	/* force user max rate if set by user */
661 	if (max_rate_idx != -1 && max_rate_idx < idx) {
662 		if (rate_mask & (1 << max_rate_idx))
663 			idx = max_rate_idx;
664 	}
665 
666 	win = &(rs_sta->win[idx]);
667 
668 	fail_count = win->counter - win->success_counter;
669 
670 	if (fail_count < RATE_MIN_FAILURE_TH &&
671 	    win->success_counter < RATE_MIN_SUCCESS_TH) {
672 		spin_unlock_irqrestore(&rs_sta->lock, flags);
673 
674 		D_RATE("Invalid average_tpt on rate %d: "
675 		       "counter: %d, success_counter: %d, "
676 		       "expected_tpt is %sNULL\n", idx, win->counter,
677 		       win->success_counter,
678 		       rs_sta->expected_tpt ? "not " : "");
679 
680 		/* Can't calculate this yet; not enough history */
681 		win->average_tpt = IL_INVALID_VALUE;
682 		goto out;
683 
684 	}
685 
686 	current_tpt = win->average_tpt;
687 
688 	high_low =
689 	    il3945_get_adjacent_rate(rs_sta, idx, rate_mask, sband->band);
690 	low = high_low & 0xff;
691 	high = (high_low >> 8) & 0xff;
692 
693 	/* If user set max rate, dont allow higher than user constrain */
694 	if (max_rate_idx != -1 && max_rate_idx < high)
695 		high = RATE_INVALID;
696 
697 	/* Collect Measured throughputs of adjacent rates */
698 	if (low != RATE_INVALID)
699 		low_tpt = rs_sta->win[low].average_tpt;
700 
701 	if (high != RATE_INVALID)
702 		high_tpt = rs_sta->win[high].average_tpt;
703 
704 	spin_unlock_irqrestore(&rs_sta->lock, flags);
705 
706 	scale_action = 0;
707 
708 	/* Low success ratio , need to drop the rate */
709 	if (win->success_ratio < RATE_DECREASE_TH || !current_tpt) {
710 		D_RATE("decrease rate because of low success_ratio\n");
711 		scale_action = -1;
712 		/* No throughput measured yet for adjacent rates,
713 		 * try increase */
714 	} else if (low_tpt == IL_INVALID_VALUE && high_tpt == IL_INVALID_VALUE) {
715 
716 		if (high != RATE_INVALID &&
717 		    win->success_ratio >= RATE_INCREASE_TH)
718 			scale_action = 1;
719 		else if (low != RATE_INVALID)
720 			scale_action = 0;
721 
722 		/* Both adjacent throughputs are measured, but neither one has
723 		 * better throughput; we're using the best rate, don't change
724 		 * it! */
725 	} else if (low_tpt != IL_INVALID_VALUE && high_tpt != IL_INVALID_VALUE
726 		   && low_tpt < current_tpt && high_tpt < current_tpt) {
727 
728 		D_RATE("No action -- low [%d] & high [%d] < "
729 		       "current_tpt [%d]\n", low_tpt, high_tpt, current_tpt);
730 		scale_action = 0;
731 
732 		/* At least one of the rates has better throughput */
733 	} else {
734 		if (high_tpt != IL_INVALID_VALUE) {
735 
736 			/* High rate has better throughput, Increase
737 			 * rate */
738 			if (high_tpt > current_tpt &&
739 			    win->success_ratio >= RATE_INCREASE_TH)
740 				scale_action = 1;
741 			else {
742 				D_RATE("decrease rate because of high tpt\n");
743 				scale_action = 0;
744 			}
745 		} else if (low_tpt != IL_INVALID_VALUE) {
746 			if (low_tpt > current_tpt) {
747 				D_RATE("decrease rate because of low tpt\n");
748 				scale_action = -1;
749 			} else if (win->success_ratio >= RATE_INCREASE_TH) {
750 				/* Lower rate has better
751 				 * throughput,decrease rate */
752 				scale_action = 1;
753 			}
754 		}
755 	}
756 
757 	/* Sanity check; asked for decrease, but success rate or throughput
758 	 * has been good at old rate.  Don't change it. */
759 	if (scale_action == -1 && low != RATE_INVALID &&
760 	    (win->success_ratio > RATE_HIGH_TH ||
761 	     current_tpt > 100 * rs_sta->expected_tpt[low]))
762 		scale_action = 0;
763 
764 	switch (scale_action) {
765 	case -1:
766 		/* Decrease rate */
767 		if (low != RATE_INVALID)
768 			idx = low;
769 		break;
770 	case 1:
771 		/* Increase rate */
772 		if (high != RATE_INVALID)
773 			idx = high;
774 
775 		break;
776 	case 0:
777 	default:
778 		/* No change */
779 		break;
780 	}
781 
782 	D_RATE("Selected %d (action %d) - low %d high %d\n", idx, scale_action,
783 	       low, high);
784 
785 out:
786 
787 	if (sband->band == NL80211_BAND_5GHZ) {
788 		if (WARN_ON_ONCE(idx < IL_FIRST_OFDM_RATE))
789 			idx = IL_FIRST_OFDM_RATE;
790 		rs_sta->last_txrate_idx = idx;
791 		info->control.rates[0].idx = idx - IL_FIRST_OFDM_RATE;
792 	} else {
793 		rs_sta->last_txrate_idx = idx;
794 		info->control.rates[0].idx = rs_sta->last_txrate_idx;
795 	}
796 	info->control.rates[0].count = 1;
797 
798 	D_RATE("leave: %d\n", idx);
799 }
800 
801 #ifdef CONFIG_MAC80211_DEBUGFS
802 
803 static ssize_t
804 il3945_sta_dbgfs_stats_table_read(struct file *file, char __user *user_buf,
805 				  size_t count, loff_t *ppos)
806 {
807 	char *buff;
808 	int desc = 0;
809 	int j;
810 	ssize_t ret;
811 	struct il3945_rs_sta *lq_sta = file->private_data;
812 
813 	buff = kmalloc(1024, GFP_KERNEL);
814 	if (!buff)
815 		return -ENOMEM;
816 
817 	desc +=
818 	    sprintf(buff + desc,
819 		    "tx packets=%d last rate idx=%d\n"
820 		    "rate=0x%X flush time %d\n", lq_sta->tx_packets,
821 		    lq_sta->last_txrate_idx, lq_sta->start_rate,
822 		    jiffies_to_msecs(lq_sta->flush_time));
823 	for (j = 0; j < RATE_COUNT_3945; j++) {
824 		desc +=
825 		    sprintf(buff + desc, "counter=%d success=%d %%=%d\n",
826 			    lq_sta->win[j].counter,
827 			    lq_sta->win[j].success_counter,
828 			    lq_sta->win[j].success_ratio);
829 	}
830 	ret = simple_read_from_buffer(user_buf, count, ppos, buff, desc);
831 	kfree(buff);
832 	return ret;
833 }
834 
835 static const struct file_operations rs_sta_dbgfs_stats_table_ops = {
836 	.read = il3945_sta_dbgfs_stats_table_read,
837 	.open = simple_open,
838 	.llseek = default_llseek,
839 };
840 
841 static void
842 il3945_add_debugfs(void *il, void *il_sta, struct dentry *dir)
843 {
844 	struct il3945_rs_sta *lq_sta = il_sta;
845 
846 	debugfs_create_file("rate_stats_table", 0600, dir, lq_sta,
847 			    &rs_sta_dbgfs_stats_table_ops);
848 }
849 #endif
850 
851 /*
852  * Initialization of rate scaling information is done by driver after
853  * the station is added. Since mac80211 calls this function before a
854  * station is added we ignore it.
855  */
856 static void
857 il3945_rs_rate_init_stub(void *il_r, struct ieee80211_supported_band *sband,
858 			 struct cfg80211_chan_def *chandef,
859 			 struct ieee80211_sta *sta, void *il_sta)
860 {
861 }
862 
863 static const struct rate_control_ops rs_ops = {
864 	.name = RS_NAME,
865 	.tx_status = il3945_rs_tx_status,
866 	.get_rate = il3945_rs_get_rate,
867 	.rate_init = il3945_rs_rate_init_stub,
868 	.alloc = il3945_rs_alloc,
869 	.free = il3945_rs_free,
870 	.alloc_sta = il3945_rs_alloc_sta,
871 	.free_sta = il3945_rs_free_sta,
872 #ifdef CONFIG_MAC80211_DEBUGFS
873 	.add_sta_debugfs = il3945_add_debugfs,
874 #endif
875 
876 };
877 
878 void
879 il3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
880 {
881 	struct il_priv *il = hw->priv;
882 	s32 rssi = 0;
883 	unsigned long flags;
884 	struct il3945_rs_sta *rs_sta;
885 	struct ieee80211_sta *sta;
886 	struct il3945_sta_priv *psta;
887 
888 	D_RATE("enter\n");
889 
890 	rcu_read_lock();
891 
892 	sta = ieee80211_find_sta(il->vif, il->stations[sta_id].sta.sta.addr);
893 	if (!sta) {
894 		D_RATE("Unable to find station to initialize rate scaling.\n");
895 		rcu_read_unlock();
896 		return;
897 	}
898 
899 	psta = (void *)sta->drv_priv;
900 	rs_sta = &psta->rs_sta;
901 
902 	spin_lock_irqsave(&rs_sta->lock, flags);
903 
904 	rs_sta->tgg = 0;
905 	switch (il->band) {
906 	case NL80211_BAND_2GHZ:
907 		/* TODO: this always does G, not a regression */
908 		if (il->active.flags & RXON_FLG_TGG_PROTECT_MSK) {
909 			rs_sta->tgg = 1;
910 			rs_sta->expected_tpt = il3945_expected_tpt_g_prot;
911 		} else
912 			rs_sta->expected_tpt = il3945_expected_tpt_g;
913 		break;
914 	case NL80211_BAND_5GHZ:
915 		rs_sta->expected_tpt = il3945_expected_tpt_a;
916 		break;
917 	default:
918 		BUG();
919 		break;
920 	}
921 
922 	spin_unlock_irqrestore(&rs_sta->lock, flags);
923 
924 	rssi = il->_3945.last_rx_rssi;
925 	if (rssi == 0)
926 		rssi = IL_MIN_RSSI_VAL;
927 
928 	D_RATE("Network RSSI: %d\n", rssi);
929 
930 	rs_sta->start_rate = il3945_get_rate_idx_by_rssi(rssi, il->band);
931 
932 	D_RATE("leave: rssi %d assign rate idx: " "%d (plcp 0x%x)\n", rssi,
933 	       rs_sta->start_rate, il3945_rates[rs_sta->start_rate].plcp);
934 	rcu_read_unlock();
935 }
936 
937 int
938 il3945_rate_control_register(void)
939 {
940 	return ieee80211_rate_control_register(&rs_ops);
941 }
942 
943 void
944 il3945_rate_control_unregister(void)
945 {
946 	ieee80211_rate_control_unregister(&rs_ops);
947 }
948