3945-rs.c

  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
 28static s32 il3945_expected_tpt_g[RATE_COUNT_3945] = {
 29	7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
 30};
 31
 32static s32 il3945_expected_tpt_g_prot[RATE_COUNT_3945] = {
 33	7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
 34};
 35
 36static s32 il3945_expected_tpt_a[RATE_COUNT_3945] = {
 37	0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186
 38};
 39
 40static s32 il3945_expected_tpt_b[RATE_COUNT_3945] = {
 41	7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
 42};
 43
 44struct il3945_tpt_entry {
 45	s8 min_rssi;
 46	u8 idx;
 47};
 48
 49static 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
 60static 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
 84static u8
 85il3945_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
116static void
117il3945_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 */
134static int
135il3945_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
168static void
169il3945_bg_rate_scale_flush(struct timer_list *t)
170{
171	struct il3945_rs_sta *rs_sta = timer_container_of(rs_sta, t,
172							  rate_scale_flush);
173	struct il_priv *il __maybe_unused = rs_sta->il;
174	int unflushed = 0;
175	unsigned long flags;
176	u32 packet_count, duration, pps;
177
178	D_RATE("enter\n");
179
180	unflushed = il3945_rate_scale_flush_wins(rs_sta);
181
182	spin_lock_irqsave(&rs_sta->lock, flags);
183
184	/* Number of packets Rx'd since last time this timer ran */
185	packet_count = (rs_sta->tx_packets - rs_sta->last_tx_packets) + 1;
186
187	rs_sta->last_tx_packets = rs_sta->tx_packets + 1;
188
189	if (unflushed) {
190		duration =
191		    jiffies_to_msecs(jiffies - rs_sta->last_partial_flush);
192
193		D_RATE("Tx'd %d packets in %dms\n", packet_count, duration);
194
195		/* Determine packets per second */
196		if (duration)
197			pps = (packet_count * 1000) / duration;
198		else
199			pps = 0;
200
201		if (pps) {
202			duration = (IL_AVERAGE_PACKETS * 1000) / pps;
203			if (duration < RATE_FLUSH_MIN)
204				duration = RATE_FLUSH_MIN;
205			else if (duration > RATE_FLUSH_MAX)
206				duration = RATE_FLUSH_MAX;
207		} else
208			duration = RATE_FLUSH_MAX;
209
210		rs_sta->flush_time = msecs_to_jiffies(duration);
211
212		D_RATE("new flush period: %d msec ave %d\n", duration,
213		       packet_count);
214
215		mod_timer(&rs_sta->rate_scale_flush,
216			  jiffies + rs_sta->flush_time);
217
218		rs_sta->last_partial_flush = jiffies;
219	} else {
220		rs_sta->flush_time = RATE_FLUSH;
221		rs_sta->flush_pending = 0;
222	}
223	/* If there weren't any unflushed entries, we don't schedule the timer
224	 * to run again */
225
226	rs_sta->last_flush = jiffies;
227
228	spin_unlock_irqrestore(&rs_sta->lock, flags);
229
230	D_RATE("leave\n");
231}
232
233/*
234 * il3945_collect_tx_data - Update the success/failure sliding win
235 *
236 * We keep a sliding win of the last 64 packets transmitted
237 * at this rate.  win->data contains the bitmask of successful
238 * packets.
239 */
240static void
241il3945_collect_tx_data(struct il3945_rs_sta *rs_sta,
242		       struct il3945_rate_scale_data *win, int success,
243		       int retries, int idx)
244{
245	unsigned long flags;
246	s32 fail_count;
247	struct il_priv *il __maybe_unused = rs_sta->il;
248
249	if (!retries) {
250		D_RATE("leave: retries == 0 -- should be at least 1\n");
251		return;
252	}
253
254	spin_lock_irqsave(&rs_sta->lock, flags);
255
256	/*
257	 * Keep track of only the latest 62 tx frame attempts in this rate's
258	 * history win; anything older isn't really relevant any more.
259	 * If we have filled up the sliding win, drop the oldest attempt;
260	 * if the oldest attempt (highest bit in bitmap) shows "success",
261	 * subtract "1" from the success counter (this is the main reason
262	 * we keep these bitmaps!).
263	 * */
264	while (retries > 0) {
265		if (win->counter >= RATE_MAX_WINDOW) {
266
267			/* remove earliest */
268			win->counter = RATE_MAX_WINDOW - 1;
269
270			if (win->data & (1ULL << (RATE_MAX_WINDOW - 1))) {
271				win->data &= ~(1ULL << (RATE_MAX_WINDOW - 1));
272				win->success_counter--;
273			}
274		}
275
276		/* Increment frames-attempted counter */
277		win->counter++;
278
279		/* Shift bitmap by one frame (throw away oldest history),
280		 * OR in "1", and increment "success" if this
281		 * frame was successful. */
282		win->data <<= 1;
283		if (success > 0) {
284			win->success_counter++;
285			win->data |= 0x1;
286			success--;
287		}
288
289		retries--;
290	}
291
292	/* Calculate current success ratio, avoid divide-by-0! */
293	if (win->counter > 0)
294		win->success_ratio =
295		    128 * (100 * win->success_counter) / win->counter;
296	else
297		win->success_ratio = IL_INVALID_VALUE;
298
299	fail_count = win->counter - win->success_counter;
300
301	/* Calculate average throughput, if we have enough history. */
302	if (fail_count >= RATE_MIN_FAILURE_TH ||
303	    win->success_counter >= RATE_MIN_SUCCESS_TH)
304		win->average_tpt =
305		    ((win->success_ratio * rs_sta->expected_tpt[idx] +
306		      64) / 128);
307	else
308		win->average_tpt = IL_INVALID_VALUE;
309
310	/* Tag this win as having been updated */
311	win->stamp = jiffies;
312
313	spin_unlock_irqrestore(&rs_sta->lock, flags);
314}
315
316/*
317 * Called after adding a new station to initialize rate scaling
318 */
319void
320il3945_rs_rate_init(struct il_priv *il, struct ieee80211_sta *sta, u8 sta_id)
321{
322	struct ieee80211_hw *hw = il->hw;
323	struct ieee80211_conf *conf = &il->hw->conf;
324	struct il3945_sta_priv *psta;
325	struct il3945_rs_sta *rs_sta;
326	struct ieee80211_supported_band *sband;
327	int i;
328
329	D_INFO("enter\n");
330	if (sta_id == il->hw_params.bcast_id)
331		goto out;
332
333	psta = (struct il3945_sta_priv *)sta->drv_priv;
334	rs_sta = &psta->rs_sta;
335	sband = hw->wiphy->bands[conf->chandef.chan->band];
336
337	rs_sta->il = il;
338
339	rs_sta->start_rate = RATE_INVALID;
340
341	/* default to just 802.11b */
342	rs_sta->expected_tpt = il3945_expected_tpt_b;
343
344	rs_sta->last_partial_flush = jiffies;
345	rs_sta->last_flush = jiffies;
346	rs_sta->flush_time = RATE_FLUSH;
347	rs_sta->last_tx_packets = 0;
348
349	for (i = 0; i < RATE_COUNT_3945; i++)
350		il3945_clear_win(&rs_sta->win[i]);
351
352	/* TODO: what is a good starting rate for STA? About middle? Maybe not
353	 * the lowest or the highest rate.. Could consider using RSSI from
354	 * previous packets? Need to have IEEE 802.1X auth succeed immediately
355	 * after assoc.. */
356
357	for (i = sband->n_bitrates - 1; i >= 0; i--) {
358		if (sta->deflink.supp_rates[sband->band] & (1 << i)) {
359			rs_sta->last_txrate_idx = i;
360			break;
361		}
362	}
363
364	il->_3945.sta_supp_rates = sta->deflink.supp_rates[sband->band];
365	/* For 5 GHz band it start at IL_FIRST_OFDM_RATE */
366	if (sband->band == NL80211_BAND_5GHZ) {
367		rs_sta->last_txrate_idx += IL_FIRST_OFDM_RATE;
368		il->_3945.sta_supp_rates <<= IL_FIRST_OFDM_RATE;
369	}
370
371out:
372	il->stations[sta_id].used &= ~IL_STA_UCODE_INPROGRESS;
373
374	D_INFO("leave\n");
375}
376
377static void *
378il3945_rs_alloc(struct ieee80211_hw *hw)
379{
380	return hw->priv;
381}
382
383/* rate scale requires free function to be implemented */
384static void
385il3945_rs_free(void *il)
386{
387}
388
389static void *
390il3945_rs_alloc_sta(void *il_priv, struct ieee80211_sta *sta, gfp_t gfp)
391{
392	struct il3945_rs_sta *rs_sta;
393	struct il3945_sta_priv *psta = (void *)sta->drv_priv;
394	struct il_priv *il __maybe_unused = il_priv;
395
396	D_RATE("enter\n");
397
398	rs_sta = &psta->rs_sta;
399
400	spin_lock_init(&rs_sta->lock);
401	timer_setup(&rs_sta->rate_scale_flush, il3945_bg_rate_scale_flush, 0);
402	D_RATE("leave\n");
403
404	return rs_sta;
405}
406
407static void
408il3945_rs_free_sta(void *il_priv, struct ieee80211_sta *sta, void *il_sta)
409{
410	struct il3945_rs_sta *rs_sta = il_sta;
411
412	/*
413	 * Be careful not to use any members of il3945_rs_sta (like trying
414	 * to use il_priv to print out debugging) since it may not be fully
415	 * initialized at this point.
416	 */
417	timer_delete_sync(&rs_sta->rate_scale_flush);
418}
419
420/*
421 * il3945_rs_tx_status - Update rate control values based on Tx results
422 *
423 * NOTE: Uses il_priv->retry_rate for the # of retries attempted by
424 * the hardware for each rate.
425 */
426static void
427il3945_rs_tx_status(void *il_rate, struct ieee80211_supported_band *sband,
428		    struct ieee80211_sta *sta, void *il_sta,
429		    struct sk_buff *skb)
430{
431	s8 retries = 0, current_count;
432	int scale_rate_idx, first_idx, last_idx;
433	unsigned long flags;
434	struct il_priv *il = (struct il_priv *)il_rate;
435	struct il3945_rs_sta *rs_sta = il_sta;
436	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
437
438	D_RATE("enter\n");
439
440	retries = info->status.rates[0].count;
441	/* Sanity Check for retries */
442	if (retries > RATE_RETRY_TH)
443		retries = RATE_RETRY_TH;
444
445	first_idx = sband->bitrates[info->status.rates[0].idx].hw_value;
446	if (first_idx < 0 || first_idx >= RATE_COUNT_3945) {
447		D_RATE("leave: Rate out of bounds: %d\n", first_idx);
448		return;
449	}
450
451	if (!il_sta) {
452		D_RATE("leave: No STA il data to update!\n");
453		return;
454	}
455
456	/* Treat uninitialized rate scaling data same as non-existing. */
457	if (!rs_sta->il) {
458		D_RATE("leave: STA il data uninitialized!\n");
459		return;
460	}
461
462	rs_sta->tx_packets++;
463
464	scale_rate_idx = first_idx;
465	last_idx = first_idx;
466
467	/*
468	 * Update the win for each rate.  We determine which rates
469	 * were Tx'd based on the total number of retries vs. the number
470	 * of retries configured for each rate -- currently set to the
471	 * il value 'retry_rate' vs. rate specific
472	 *
473	 * On exit from this while loop last_idx indicates the rate
474	 * at which the frame was finally transmitted (or failed if no
475	 * ACK)
476	 */
477	while (retries > 1) {
478		if ((retries - 1) < il->retry_rate) {
479			current_count = (retries - 1);
480			last_idx = scale_rate_idx;
481		} else {
482			current_count = il->retry_rate;
483			last_idx = il3945_rs_next_rate(il, scale_rate_idx);
484		}
485
486		/* Update this rate accounting for as many retries
487		 * as was used for it (per current_count) */
488		il3945_collect_tx_data(rs_sta, &rs_sta->win[scale_rate_idx], 0,
489				       current_count, scale_rate_idx);
490		D_RATE("Update rate %d for %d retries.\n", scale_rate_idx,
491		       current_count);
492
493		retries -= current_count;
494
495		scale_rate_idx = last_idx;
496	}
497
498	/* Update the last idx win with success/failure based on ACK */
499	D_RATE("Update rate %d with %s.\n", last_idx,
500	       (info->flags & IEEE80211_TX_STAT_ACK) ? "success" : "failure");
501	il3945_collect_tx_data(rs_sta, &rs_sta->win[last_idx],
502			       info->flags & IEEE80211_TX_STAT_ACK, 1,
503			       last_idx);
504
505	/* We updated the rate scale win -- if its been more than
506	 * flush_time since the last run, schedule the flush
507	 * again */
508	spin_lock_irqsave(&rs_sta->lock, flags);
509
510	if (!rs_sta->flush_pending &&
511	    time_after(jiffies, rs_sta->last_flush + rs_sta->flush_time)) {
512
513		rs_sta->last_partial_flush = jiffies;
514		rs_sta->flush_pending = 1;
515		mod_timer(&rs_sta->rate_scale_flush,
516			  jiffies + rs_sta->flush_time);
517	}
518
519	spin_unlock_irqrestore(&rs_sta->lock, flags);
520
521	D_RATE("leave\n");
522}
523
524static u16
525il3945_get_adjacent_rate(struct il3945_rs_sta *rs_sta, u8 idx, u16 rate_mask,
526			 enum nl80211_band band)
527{
528	u8 high = RATE_INVALID;
529	u8 low = RATE_INVALID;
530	struct il_priv *il __maybe_unused = rs_sta->il;
531
532	/* 802.11A walks to the next literal adjacent rate in
533	 * the rate table */
534	if (unlikely(band == NL80211_BAND_5GHZ)) {
535		int i;
536		u32 mask;
537
538		/* Find the previous rate that is in the rate mask */
539		i = idx - 1;
540		for (mask = (1 << i); i >= 0; i--, mask >>= 1) {
541			if (rate_mask & mask) {
542				low = i;
543				break;
544			}
545		}
546
547		/* Find the next rate that is in the rate mask */
548		i = idx + 1;
549		for (mask = (1 << i); i < RATE_COUNT_3945; i++, mask <<= 1) {
550			if (rate_mask & mask) {
551				high = i;
552				break;
553			}
554		}
555
556		return (high << 8) | low;
557	}
558
559	low = idx;
560	while (low != RATE_INVALID) {
561		if (rs_sta->tgg)
562			low = il3945_rates[low].prev_rs_tgg;
563		else
564			low = il3945_rates[low].prev_rs;
565		if (low == RATE_INVALID)
566			break;
567		if (rate_mask & (1 << low))
568			break;
569		D_RATE("Skipping masked lower rate: %d\n", low);
570	}
571
572	high = idx;
573	while (high != RATE_INVALID) {
574		if (rs_sta->tgg)
575			high = il3945_rates[high].next_rs_tgg;
576		else
577			high = il3945_rates[high].next_rs;
578		if (high == RATE_INVALID)
579			break;
580		if (rate_mask & (1 << high))
581			break;
582		D_RATE("Skipping masked higher rate: %d\n", high);
583	}
584
585	return (high << 8) | low;
586}
587
588/*
589 * il3945_rs_get_rate - find the rate for the requested packet
590 *
591 * Returns the ieee80211_rate structure allocated by the driver.
592 *
593 * The rate control algorithm has no internal mapping between hw_mode's
594 * rate ordering and the rate ordering used by the rate control algorithm.
595 *
596 * The rate control algorithm uses a single table of rates that goes across
597 * the entire A/B/G spectrum vs. being limited to just one particular
598 * hw_mode.
599 *
600 * As such, we can't convert the idx obtained below into the hw_mode's
601 * rate table and must reference the driver allocated rate table
602 *
603 */
604static void
605il3945_rs_get_rate(void *il_r, struct ieee80211_sta *sta, void *il_sta,
606		   struct ieee80211_tx_rate_control *txrc)
607{
608	struct ieee80211_supported_band *sband = txrc->sband;
609	struct sk_buff *skb = txrc->skb;
610	u8 low = RATE_INVALID;
611	u8 high = RATE_INVALID;
612	u16 high_low;
613	int idx;
614	struct il3945_rs_sta *rs_sta = il_sta;
615	struct il3945_rate_scale_data *win = NULL;
616	int current_tpt = IL_INVALID_VALUE;
617	int low_tpt = IL_INVALID_VALUE;
618	int high_tpt = IL_INVALID_VALUE;
619	u32 fail_count;
620	s8 scale_action = 0;
621	unsigned long flags;
622	u16 rate_mask;
623	s8 max_rate_idx = -1;
624	struct il_priv *il __maybe_unused = (struct il_priv *)il_r;
625	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
626
627	D_RATE("enter\n");
628
629	/* Treat uninitialized rate scaling data same as non-existing. */
630	if (rs_sta && !rs_sta->il) {
631		D_RATE("Rate scaling information not initialized yet.\n");
632		il_sta = NULL;
633	}
634
635	rate_mask = sta->deflink.supp_rates[sband->band];
636
637	/* get user max rate if set */
638	max_rate_idx = fls(txrc->rate_idx_mask) - 1;
639	if (sband->band == NL80211_BAND_5GHZ && max_rate_idx != -1)
640		max_rate_idx += IL_FIRST_OFDM_RATE;
641	if (max_rate_idx < 0 || max_rate_idx >= RATE_COUNT)
642		max_rate_idx = -1;
643
644	idx = min(rs_sta->last_txrate_idx & 0xffff, RATE_COUNT_3945 - 1);
645
646	if (sband->band == NL80211_BAND_5GHZ)
647		rate_mask = rate_mask << IL_FIRST_OFDM_RATE;
648
649	spin_lock_irqsave(&rs_sta->lock, flags);
650
651	/* for recent assoc, choose best rate regarding
652	 * to rssi value
653	 */
654	if (rs_sta->start_rate != RATE_INVALID) {
655		if (rs_sta->start_rate < idx &&
656		    (rate_mask & (1 << rs_sta->start_rate)))
657			idx = rs_sta->start_rate;
658		rs_sta->start_rate = RATE_INVALID;
659	}
660
661	/* force user max rate if set by user */
662	if (max_rate_idx != -1 && max_rate_idx < idx) {
663		if (rate_mask & (1 << max_rate_idx))
664			idx = max_rate_idx;
665	}
666
667	win = &(rs_sta->win[idx]);
668
669	fail_count = win->counter - win->success_counter;
670
671	if (fail_count < RATE_MIN_FAILURE_TH &&
672	    win->success_counter < RATE_MIN_SUCCESS_TH) {
673		spin_unlock_irqrestore(&rs_sta->lock, flags);
674
675		D_RATE("Invalid average_tpt on rate %d: "
676		       "counter: %d, success_counter: %d, "
677		       "expected_tpt is %sNULL\n", idx, win->counter,
678		       win->success_counter,
679		       rs_sta->expected_tpt ? "not " : "");
680
681		/* Can't calculate this yet; not enough history */
682		win->average_tpt = IL_INVALID_VALUE;
683		goto out;
684
685	}
686
687	current_tpt = win->average_tpt;
688
689	high_low =
690	    il3945_get_adjacent_rate(rs_sta, idx, rate_mask, sband->band);
691	low = high_low & 0xff;
692	high = (high_low >> 8) & 0xff;
693
694	/* If user set max rate, dont allow higher than user constrain */
695	if (max_rate_idx != -1 && max_rate_idx < high)
696		high = RATE_INVALID;
697
698	/* Collect Measured throughputs of adjacent rates */
699	if (low != RATE_INVALID)
700		low_tpt = rs_sta->win[low].average_tpt;
701
702	if (high != RATE_INVALID)
703		high_tpt = rs_sta->win[high].average_tpt;
704
705	spin_unlock_irqrestore(&rs_sta->lock, flags);
706
707	scale_action = 0;
708
709	/* Low success ratio , need to drop the rate */
710	if (win->success_ratio < RATE_DECREASE_TH || !current_tpt) {
711		D_RATE("decrease rate because of low success_ratio\n");
712		scale_action = -1;
713		/* No throughput measured yet for adjacent rates,
714		 * try increase */
715	} else if (low_tpt == IL_INVALID_VALUE && high_tpt == IL_INVALID_VALUE) {
716
717		if (high != RATE_INVALID &&
718		    win->success_ratio >= RATE_INCREASE_TH)
719			scale_action = 1;
720		else if (low != RATE_INVALID)
721			scale_action = 0;
722
723		/* Both adjacent throughputs are measured, but neither one has
724		 * better throughput; we're using the best rate, don't change
725		 * it! */
726	} else if (low_tpt != IL_INVALID_VALUE && high_tpt != IL_INVALID_VALUE
727		   && low_tpt < current_tpt && high_tpt < current_tpt) {
728
729		D_RATE("No action -- low [%d] & high [%d] < "
730		       "current_tpt [%d]\n", low_tpt, high_tpt, current_tpt);
731		scale_action = 0;
732
733		/* At least one of the rates has better throughput */
734	} else {
735		if (high_tpt != IL_INVALID_VALUE) {
736
737			/* High rate has better throughput, Increase
738			 * rate */
739			if (high_tpt > current_tpt &&
740			    win->success_ratio >= RATE_INCREASE_TH)
741				scale_action = 1;
742			else {
743				D_RATE("decrease rate because of high tpt\n");
744				scale_action = 0;
745			}
746		} else if (low_tpt != IL_INVALID_VALUE) {
747			if (low_tpt > current_tpt) {
748				D_RATE("decrease rate because of low tpt\n");
749				scale_action = -1;
750			} else if (win->success_ratio >= RATE_INCREASE_TH) {
751				/* Lower rate has better
752				 * throughput,decrease rate */
753				scale_action = 1;
754			}
755		}
756	}
757
758	/* Sanity check; asked for decrease, but success rate or throughput
759	 * has been good at old rate.  Don't change it. */
760	if (scale_action == -1 && low != RATE_INVALID &&
761	    (win->success_ratio > RATE_HIGH_TH ||
762	     current_tpt > 100 * rs_sta->expected_tpt[low]))
763		scale_action = 0;
764
765	switch (scale_action) {
766	case -1:
767		/* Decrease rate */
768		if (low != RATE_INVALID)
769			idx = low;
770		break;
771	case 1:
772		/* Increase rate */
773		if (high != RATE_INVALID)
774			idx = high;
775
776		break;
777	case 0:
778	default:
779		/* No change */
780		break;
781	}
782
783	D_RATE("Selected %d (action %d) - low %d high %d\n", idx, scale_action,
784	       low, high);
785
786out:
787
788	if (sband->band == NL80211_BAND_5GHZ) {
789		if (WARN_ON_ONCE(idx < IL_FIRST_OFDM_RATE))
790			idx = IL_FIRST_OFDM_RATE;
791		rs_sta->last_txrate_idx = idx;
792		info->control.rates[0].idx = idx - IL_FIRST_OFDM_RATE;
793	} else {
794		rs_sta->last_txrate_idx = idx;
795		info->control.rates[0].idx = rs_sta->last_txrate_idx;
796	}
797	info->control.rates[0].count = 1;
798
799	D_RATE("leave: %d\n", idx);
800}
801
802#ifdef CONFIG_MAC80211_DEBUGFS
803
804static ssize_t
805il3945_sta_dbgfs_stats_table_read(struct file *file, char __user *user_buf,
806				  size_t count, loff_t *ppos)
807{
808	char *buff;
809	int desc = 0;
810	int j;
811	ssize_t ret;
812	struct il3945_rs_sta *lq_sta = file->private_data;
813
814	buff = kmalloc(1024, GFP_KERNEL);
815	if (!buff)
816		return -ENOMEM;
817
818	desc +=
819	    sprintf(buff + desc,
820		    "tx packets=%d last rate idx=%d\n"
821		    "rate=0x%X flush time %d\n", lq_sta->tx_packets,
822		    lq_sta->last_txrate_idx, lq_sta->start_rate,
823		    jiffies_to_msecs(lq_sta->flush_time));
824	for (j = 0; j < RATE_COUNT_3945; j++) {
825		desc +=
826		    sprintf(buff + desc, "counter=%d success=%d %%=%d\n",
827			    lq_sta->win[j].counter,
828			    lq_sta->win[j].success_counter,
829			    lq_sta->win[j].success_ratio);
830	}
831	ret = simple_read_from_buffer(user_buf, count, ppos, buff, desc);
832	kfree(buff);
833	return ret;
834}
835
836static const struct file_operations rs_sta_dbgfs_stats_table_ops = {
837	.read = il3945_sta_dbgfs_stats_table_read,
838	.open = simple_open,
839	.llseek = default_llseek,
840};
841
842static void
843il3945_add_debugfs(void *il, void *il_sta, struct dentry *dir)
844{
845	struct il3945_rs_sta *lq_sta = il_sta;
846
847	debugfs_create_file("rate_stats_table", 0600, dir, lq_sta,
848			    &rs_sta_dbgfs_stats_table_ops);
849}
850#endif
851
852/*
853 * Initialization of rate scaling information is done by driver after
854 * the station is added. Since mac80211 calls this function before a
855 * station is added we ignore it.
856 */
857static void
858il3945_rs_rate_init_stub(void *il_r, struct ieee80211_supported_band *sband,
859			 struct cfg80211_chan_def *chandef,
860			 struct ieee80211_sta *sta, void *il_sta)
861{
862}
863
864static const struct rate_control_ops rs_ops = {
865	.name = RS_NAME,
866	.tx_status = il3945_rs_tx_status,
867	.get_rate = il3945_rs_get_rate,
868	.rate_init = il3945_rs_rate_init_stub,
869	.alloc = il3945_rs_alloc,
870	.free = il3945_rs_free,
871	.alloc_sta = il3945_rs_alloc_sta,
872	.free_sta = il3945_rs_free_sta,
873#ifdef CONFIG_MAC80211_DEBUGFS
874	.add_sta_debugfs = il3945_add_debugfs,
875#endif
876
877};
878
879void
880il3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
881{
882	struct il_priv *il = hw->priv;
883	s32 rssi = 0;
884	unsigned long flags;
885	struct il3945_rs_sta *rs_sta;
886	struct ieee80211_sta *sta;
887	struct il3945_sta_priv *psta;
888
889	D_RATE("enter\n");
890
891	rcu_read_lock();
892
893	sta = ieee80211_find_sta(il->vif, il->stations[sta_id].sta.sta.addr);
894	if (!sta) {
895		D_RATE("Unable to find station to initialize rate scaling.\n");
896		rcu_read_unlock();
897		return;
898	}
899
900	psta = (void *)sta->drv_priv;
901	rs_sta = &psta->rs_sta;
902
903	spin_lock_irqsave(&rs_sta->lock, flags);
904
905	rs_sta->tgg = 0;
906	switch (il->band) {
907	case NL80211_BAND_2GHZ:
908		/* TODO: this always does G, not a regression */
909		if (il->active.flags & RXON_FLG_TGG_PROTECT_MSK) {
910			rs_sta->tgg = 1;
911			rs_sta->expected_tpt = il3945_expected_tpt_g_prot;
912		} else
913			rs_sta->expected_tpt = il3945_expected_tpt_g;
914		break;
915	case NL80211_BAND_5GHZ:
916		rs_sta->expected_tpt = il3945_expected_tpt_a;
917		break;
918	default:
919		BUG();
920		break;
921	}
922
923	spin_unlock_irqrestore(&rs_sta->lock, flags);
924
925	rssi = il->_3945.last_rx_rssi;
926	if (rssi == 0)
927		rssi = IL_MIN_RSSI_VAL;
928
929	D_RATE("Network RSSI: %d\n", rssi);
930
931	rs_sta->start_rate = il3945_get_rate_idx_by_rssi(rssi, il->band);
932
933	D_RATE("leave: rssi %d assign rate idx: " "%d (plcp 0x%x)\n", rssi,
934	       rs_sta->start_rate, il3945_rates[rs_sta->start_rate].plcp);
935	rcu_read_unlock();
936}
937
938int
939il3945_rate_control_register(void)
940{
941	return ieee80211_rate_control_register(&rs_ops);
942}
943
944void
945il3945_rate_control_unregister(void)
946{
947	ieee80211_rate_control_unregister(&rs_ops);
948}