1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
4  * Copyright (C) 2019-2020 Intel Corporation
5  */
6 #include <linux/netdevice.h>
7 #include <linux/types.h>
8 #include <linux/skbuff.h>
9 #include <linux/debugfs.h>
10 #include <linux/random.h>
11 #include <linux/moduleparam.h>
12 #include <linux/ieee80211.h>
13 #include <net/mac80211.h>
14 #include "rate.h"
15 #include "sta_info.h"
16 #include "rc80211_minstrel_ht.h"
17 
18 #define AVG_AMPDU_SIZE	16
19 #define AVG_PKT_SIZE	1200
20 
21 #define SAMPLE_SWITCH_THR	100
22 
23 /* Number of bits for an average sized packet */
24 #define MCS_NBITS ((AVG_PKT_SIZE * AVG_AMPDU_SIZE) << 3)
25 
26 /* Number of symbols for a packet with (bps) bits per symbol */
27 #define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
28 
29 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
30 #define MCS_SYMBOL_TIME(sgi, syms)					\
31 	(sgi ?								\
32 	  ((syms) * 18000 + 4000) / 5 :	/* syms * 3.6 us */		\
33 	  ((syms) * 1000) << 2		/* syms * 4 us */		\
34 	)
35 
36 /* Transmit duration for the raw data part of an average sized packet */
37 #define MCS_DURATION(streams, sgi, bps) \
38 	(MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) / AVG_AMPDU_SIZE)
39 
40 #define BW_20			0
41 #define BW_40			1
42 #define BW_80			2
43 
44 /*
45  * Define group sort order: HT40 -> SGI -> #streams
46  */
47 #define GROUP_IDX(_streams, _sgi, _ht40)	\
48 	MINSTREL_HT_GROUP_0 +			\
49 	MINSTREL_MAX_STREAMS * 2 * _ht40 +	\
50 	MINSTREL_MAX_STREAMS * _sgi +	\
51 	_streams - 1
52 
53 #define _MAX(a, b) (((a)>(b))?(a):(b))
54 
55 #define GROUP_SHIFT(duration)						\
56 	_MAX(0, 16 - __builtin_clz(duration))
57 
58 /* MCS rate information for an MCS group */
59 #define __MCS_GROUP(_streams, _sgi, _ht40, _s)				\
60 	[GROUP_IDX(_streams, _sgi, _ht40)] = {				\
61 	.streams = _streams,						\
62 	.shift = _s,							\
63 	.bw = _ht40,							\
64 	.flags =							\
65 		IEEE80211_TX_RC_MCS |					\
66 		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
67 		(_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),		\
68 	.duration = {							\
69 		MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26) >> _s,	\
70 		MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52) >> _s,	\
71 		MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78) >> _s,	\
72 		MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104) >> _s,	\
73 		MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156) >> _s,	\
74 		MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208) >> _s,	\
75 		MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234) >> _s,	\
76 		MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) >> _s	\
77 	}								\
78 }
79 
80 #define MCS_GROUP_SHIFT(_streams, _sgi, _ht40)				\
81 	GROUP_SHIFT(MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26))
82 
83 #define MCS_GROUP(_streams, _sgi, _ht40)				\
84 	__MCS_GROUP(_streams, _sgi, _ht40,				\
85 		    MCS_GROUP_SHIFT(_streams, _sgi, _ht40))
86 
87 #define VHT_GROUP_IDX(_streams, _sgi, _bw)				\
88 	(MINSTREL_VHT_GROUP_0 +						\
89 	 MINSTREL_MAX_STREAMS * 2 * (_bw) +				\
90 	 MINSTREL_MAX_STREAMS * (_sgi) +				\
91 	 (_streams) - 1)
92 
93 #define BW2VBPS(_bw, r3, r2, r1)					\
94 	(_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
95 
96 #define __VHT_GROUP(_streams, _sgi, _bw, _s)				\
97 	[VHT_GROUP_IDX(_streams, _sgi, _bw)] = {			\
98 	.streams = _streams,						\
99 	.shift = _s,							\
100 	.bw = _bw,							\
101 	.flags =							\
102 		IEEE80211_TX_RC_VHT_MCS |				\
103 		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
104 		(_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH :		\
105 		 _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),	\
106 	.duration = {							\
107 		MCS_DURATION(_streams, _sgi,				\
108 			     BW2VBPS(_bw,  117,  54,  26)) >> _s,	\
109 		MCS_DURATION(_streams, _sgi,				\
110 			     BW2VBPS(_bw,  234, 108,  52)) >> _s,	\
111 		MCS_DURATION(_streams, _sgi,				\
112 			     BW2VBPS(_bw,  351, 162,  78)) >> _s,	\
113 		MCS_DURATION(_streams, _sgi,				\
114 			     BW2VBPS(_bw,  468, 216, 104)) >> _s,	\
115 		MCS_DURATION(_streams, _sgi,				\
116 			     BW2VBPS(_bw,  702, 324, 156)) >> _s,	\
117 		MCS_DURATION(_streams, _sgi,				\
118 			     BW2VBPS(_bw,  936, 432, 208)) >> _s,	\
119 		MCS_DURATION(_streams, _sgi,				\
120 			     BW2VBPS(_bw, 1053, 486, 234)) >> _s,	\
121 		MCS_DURATION(_streams, _sgi,				\
122 			     BW2VBPS(_bw, 1170, 540, 260)) >> _s,	\
123 		MCS_DURATION(_streams, _sgi,				\
124 			     BW2VBPS(_bw, 1404, 648, 312)) >> _s,	\
125 		MCS_DURATION(_streams, _sgi,				\
126 			     BW2VBPS(_bw, 1560, 720, 346)) >> _s	\
127 	}								\
128 }
129 
130 #define VHT_GROUP_SHIFT(_streams, _sgi, _bw)				\
131 	GROUP_SHIFT(MCS_DURATION(_streams, _sgi,			\
132 				 BW2VBPS(_bw,  117,  54,  26)))
133 
134 #define VHT_GROUP(_streams, _sgi, _bw)					\
135 	__VHT_GROUP(_streams, _sgi, _bw,				\
136 		    VHT_GROUP_SHIFT(_streams, _sgi, _bw))
137 
138 #define CCK_DURATION(_bitrate, _short)			\
139 	(1000 * (10 /* SIFS */ +			\
140 	 (_short ? 72 + 24 : 144 + 48) +		\
141 	 (8 * (AVG_PKT_SIZE + 4) * 10) / (_bitrate)))
142 
143 #define CCK_DURATION_LIST(_short, _s)			\
144 	CCK_DURATION(10, _short) >> _s,			\
145 	CCK_DURATION(20, _short) >> _s,			\
146 	CCK_DURATION(55, _short) >> _s,			\
147 	CCK_DURATION(110, _short) >> _s
148 
149 #define __CCK_GROUP(_s)					\
150 	[MINSTREL_CCK_GROUP] = {			\
151 		.streams = 1,				\
152 		.flags = 0,				\
153 		.shift = _s,				\
154 		.duration = {				\
155 			CCK_DURATION_LIST(false, _s),	\
156 			CCK_DURATION_LIST(true, _s)	\
157 		}					\
158 	}
159 
160 #define CCK_GROUP_SHIFT					\
161 	GROUP_SHIFT(CCK_DURATION(10, false))
162 
163 #define CCK_GROUP __CCK_GROUP(CCK_GROUP_SHIFT)
164 
165 #define OFDM_DURATION(_bitrate)				\
166 	(1000 * (16 /* SIFS + signal ext */ +		\
167 	 16 /* T_PREAMBLE */ +				\
168 	 4 /* T_SIGNAL */ +				\
169 	 4 * (((16 + 80 * (AVG_PKT_SIZE + 4) + 6) /	\
170 	      ((_bitrate) * 4)))))
171 
172 #define OFDM_DURATION_LIST(_s)				\
173 	OFDM_DURATION(60) >> _s,			\
174 	OFDM_DURATION(90) >> _s,			\
175 	OFDM_DURATION(120) >> _s,			\
176 	OFDM_DURATION(180) >> _s,			\
177 	OFDM_DURATION(240) >> _s,			\
178 	OFDM_DURATION(360) >> _s,			\
179 	OFDM_DURATION(480) >> _s,			\
180 	OFDM_DURATION(540) >> _s
181 
182 #define __OFDM_GROUP(_s)				\
183 	[MINSTREL_OFDM_GROUP] = {			\
184 		.streams = 1,				\
185 		.flags = 0,				\
186 		.shift = _s,				\
187 		.duration = {				\
188 			OFDM_DURATION_LIST(_s),		\
189 		}					\
190 	}
191 
192 #define OFDM_GROUP_SHIFT				\
193 	GROUP_SHIFT(OFDM_DURATION(60))
194 
195 #define OFDM_GROUP __OFDM_GROUP(OFDM_GROUP_SHIFT)
196 
197 
198 static bool minstrel_vht_only = true;
199 module_param(minstrel_vht_only, bool, 0644);
200 MODULE_PARM_DESC(minstrel_vht_only,
201 		 "Use only VHT rates when VHT is supported by sta.");
202 
203 /*
204  * To enable sufficiently targeted rate sampling, MCS rates are divided into
205  * groups, based on the number of streams and flags (HT40, SGI) that they
206  * use.
207  *
208  * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
209  * BW -> SGI -> #streams
210  */
211 const struct mcs_group minstrel_mcs_groups[] = {
212 	MCS_GROUP(1, 0, BW_20),
213 	MCS_GROUP(2, 0, BW_20),
214 	MCS_GROUP(3, 0, BW_20),
215 	MCS_GROUP(4, 0, BW_20),
216 
217 	MCS_GROUP(1, 1, BW_20),
218 	MCS_GROUP(2, 1, BW_20),
219 	MCS_GROUP(3, 1, BW_20),
220 	MCS_GROUP(4, 1, BW_20),
221 
222 	MCS_GROUP(1, 0, BW_40),
223 	MCS_GROUP(2, 0, BW_40),
224 	MCS_GROUP(3, 0, BW_40),
225 	MCS_GROUP(4, 0, BW_40),
226 
227 	MCS_GROUP(1, 1, BW_40),
228 	MCS_GROUP(2, 1, BW_40),
229 	MCS_GROUP(3, 1, BW_40),
230 	MCS_GROUP(4, 1, BW_40),
231 
232 	CCK_GROUP,
233 	OFDM_GROUP,
234 
235 	VHT_GROUP(1, 0, BW_20),
236 	VHT_GROUP(2, 0, BW_20),
237 	VHT_GROUP(3, 0, BW_20),
238 	VHT_GROUP(4, 0, BW_20),
239 
240 	VHT_GROUP(1, 1, BW_20),
241 	VHT_GROUP(2, 1, BW_20),
242 	VHT_GROUP(3, 1, BW_20),
243 	VHT_GROUP(4, 1, BW_20),
244 
245 	VHT_GROUP(1, 0, BW_40),
246 	VHT_GROUP(2, 0, BW_40),
247 	VHT_GROUP(3, 0, BW_40),
248 	VHT_GROUP(4, 0, BW_40),
249 
250 	VHT_GROUP(1, 1, BW_40),
251 	VHT_GROUP(2, 1, BW_40),
252 	VHT_GROUP(3, 1, BW_40),
253 	VHT_GROUP(4, 1, BW_40),
254 
255 	VHT_GROUP(1, 0, BW_80),
256 	VHT_GROUP(2, 0, BW_80),
257 	VHT_GROUP(3, 0, BW_80),
258 	VHT_GROUP(4, 0, BW_80),
259 
260 	VHT_GROUP(1, 1, BW_80),
261 	VHT_GROUP(2, 1, BW_80),
262 	VHT_GROUP(3, 1, BW_80),
263 	VHT_GROUP(4, 1, BW_80),
264 };
265 
266 const s16 minstrel_cck_bitrates[4] = { 10, 20, 55, 110 };
267 const s16 minstrel_ofdm_bitrates[8] = { 60, 90, 120, 180, 240, 360, 480, 540 };
268 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
269 static const u8 minstrel_sample_seq[] = {
270 	MINSTREL_SAMPLE_TYPE_INC,
271 	MINSTREL_SAMPLE_TYPE_JUMP,
272 	MINSTREL_SAMPLE_TYPE_INC,
273 	MINSTREL_SAMPLE_TYPE_JUMP,
274 	MINSTREL_SAMPLE_TYPE_INC,
275 	MINSTREL_SAMPLE_TYPE_SLOW,
276 };
277 
278 static void
279 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
280 
281 /*
282  * Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
283  * e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
284  *
285  * Returns the valid mcs map for struct minstrel_mcs_group_data.supported
286  */
287 static u16
288 minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
289 {
290 	u16 mask = 0;
291 
292 	if (bw == BW_20) {
293 		if (nss != 3 && nss != 6)
294 			mask = BIT(9);
295 	} else if (bw == BW_80) {
296 		if (nss == 3 || nss == 7)
297 			mask = BIT(6);
298 		else if (nss == 6)
299 			mask = BIT(9);
300 	} else {
301 		WARN_ON(bw != BW_40);
302 	}
303 
304 	switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
305 	case IEEE80211_VHT_MCS_SUPPORT_0_7:
306 		mask |= 0x300;
307 		break;
308 	case IEEE80211_VHT_MCS_SUPPORT_0_8:
309 		mask |= 0x200;
310 		break;
311 	case IEEE80211_VHT_MCS_SUPPORT_0_9:
312 		break;
313 	default:
314 		mask = 0x3ff;
315 	}
316 
317 	return 0x3ff & ~mask;
318 }
319 
320 static bool
321 minstrel_ht_is_legacy_group(int group)
322 {
323 	return group == MINSTREL_CCK_GROUP ||
324 	       group == MINSTREL_OFDM_GROUP;
325 }
326 
327 /*
328  * Look up an MCS group index based on mac80211 rate information
329  */
330 static int
331 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
332 {
333 	return GROUP_IDX((rate->idx / 8) + 1,
334 			 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
335 			 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
336 }
337 
338 static int
339 minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
340 {
341 	return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
342 			     !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
343 			     !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
344 			     2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
345 }
346 
347 static struct minstrel_rate_stats *
348 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
349 		      struct ieee80211_tx_rate *rate)
350 {
351 	int group, idx;
352 
353 	if (rate->flags & IEEE80211_TX_RC_MCS) {
354 		group = minstrel_ht_get_group_idx(rate);
355 		idx = rate->idx % 8;
356 		goto out;
357 	}
358 
359 	if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
360 		group = minstrel_vht_get_group_idx(rate);
361 		idx = ieee80211_rate_get_vht_mcs(rate);
362 		goto out;
363 	}
364 
365 	group = MINSTREL_CCK_GROUP;
366 	for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++) {
367 		if (rate->idx != mp->cck_rates[idx])
368 			continue;
369 
370 		/* short preamble */
371 		if ((mi->supported[group] & BIT(idx + 4)) &&
372 		    (rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE))
373 			idx += 4;
374 		goto out;
375 	}
376 
377 	group = MINSTREL_OFDM_GROUP;
378 	for (idx = 0; idx < ARRAY_SIZE(mp->ofdm_rates[0]); idx++)
379 		if (rate->idx == mp->ofdm_rates[mi->band][idx])
380 			goto out;
381 
382 	idx = 0;
383 out:
384 	return &mi->groups[group].rates[idx];
385 }
386 
387 static inline struct minstrel_rate_stats *
388 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
389 {
390 	return &mi->groups[MI_RATE_GROUP(index)].rates[MI_RATE_IDX(index)];
391 }
392 
393 static inline int minstrel_get_duration(int index)
394 {
395 	const struct mcs_group *group = &minstrel_mcs_groups[MI_RATE_GROUP(index)];
396 	unsigned int duration = group->duration[MI_RATE_IDX(index)];
397 
398 	return duration << group->shift;
399 }
400 
401 static unsigned int
402 minstrel_ht_avg_ampdu_len(struct minstrel_ht_sta *mi)
403 {
404 	int duration;
405 
406 	if (mi->avg_ampdu_len)
407 		return MINSTREL_TRUNC(mi->avg_ampdu_len);
408 
409 	if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(mi->max_tp_rate[0])))
410 		return 1;
411 
412 	duration = minstrel_get_duration(mi->max_tp_rate[0]);
413 
414 	if (duration > 400 * 1000)
415 		return 2;
416 
417 	if (duration > 250 * 1000)
418 		return 4;
419 
420 	if (duration > 150 * 1000)
421 		return 8;
422 
423 	return 16;
424 }
425 
426 /*
427  * Return current throughput based on the average A-MPDU length, taking into
428  * account the expected number of retransmissions and their expected length
429  */
430 int
431 minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate,
432 		       int prob_avg)
433 {
434 	unsigned int nsecs = 0, overhead = mi->overhead;
435 	unsigned int ampdu_len = 1;
436 
437 	/* do not account throughput if sucess prob is below 10% */
438 	if (prob_avg < MINSTREL_FRAC(10, 100))
439 		return 0;
440 
441 	if (minstrel_ht_is_legacy_group(group))
442 		overhead = mi->overhead_legacy;
443 	else
444 		ampdu_len = minstrel_ht_avg_ampdu_len(mi);
445 
446 	nsecs = 1000 * overhead / ampdu_len;
447 	nsecs += minstrel_mcs_groups[group].duration[rate] <<
448 		 minstrel_mcs_groups[group].shift;
449 
450 	/*
451 	 * For the throughput calculation, limit the probability value to 90% to
452 	 * account for collision related packet error rate fluctuation
453 	 * (prob is scaled - see MINSTREL_FRAC above)
454 	 */
455 	if (prob_avg > MINSTREL_FRAC(90, 100))
456 		prob_avg = MINSTREL_FRAC(90, 100);
457 
458 	return MINSTREL_TRUNC(100 * ((prob_avg * 1000000) / nsecs));
459 }
460 
461 /*
462  * Find & sort topmost throughput rates
463  *
464  * If multiple rates provide equal throughput the sorting is based on their
465  * current success probability. Higher success probability is preferred among
466  * MCS groups, CCK rates do not provide aggregation and are therefore at last.
467  */
468 static void
469 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
470 			       u16 *tp_list)
471 {
472 	int cur_group, cur_idx, cur_tp_avg, cur_prob;
473 	int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
474 	int j = MAX_THR_RATES;
475 
476 	cur_group = MI_RATE_GROUP(index);
477 	cur_idx = MI_RATE_IDX(index);
478 	cur_prob = mi->groups[cur_group].rates[cur_idx].prob_avg;
479 	cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob);
480 
481 	do {
482 		tmp_group = MI_RATE_GROUP(tp_list[j - 1]);
483 		tmp_idx = MI_RATE_IDX(tp_list[j - 1]);
484 		tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
485 		tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx,
486 						    tmp_prob);
487 		if (cur_tp_avg < tmp_tp_avg ||
488 		    (cur_tp_avg == tmp_tp_avg && cur_prob <= tmp_prob))
489 			break;
490 		j--;
491 	} while (j > 0);
492 
493 	if (j < MAX_THR_RATES - 1) {
494 		memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
495 		       (MAX_THR_RATES - (j + 1))));
496 	}
497 	if (j < MAX_THR_RATES)
498 		tp_list[j] = index;
499 }
500 
501 /*
502  * Find and set the topmost probability rate per sta and per group
503  */
504 static void
505 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 *dest, u16 index)
506 {
507 	struct minstrel_mcs_group_data *mg;
508 	struct minstrel_rate_stats *mrs;
509 	int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
510 	int max_tp_group, max_tp_idx, max_tp_prob;
511 	int cur_tp_avg, cur_group, cur_idx;
512 	int max_gpr_group, max_gpr_idx;
513 	int max_gpr_tp_avg, max_gpr_prob;
514 
515 	cur_group = MI_RATE_GROUP(index);
516 	cur_idx = MI_RATE_IDX(index);
517 	mg = &mi->groups[cur_group];
518 	mrs = &mg->rates[cur_idx];
519 
520 	tmp_group = MI_RATE_GROUP(*dest);
521 	tmp_idx = MI_RATE_IDX(*dest);
522 	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
523 	tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
524 
525 	/* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
526 	 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
527 	max_tp_group = MI_RATE_GROUP(mi->max_tp_rate[0]);
528 	max_tp_idx = MI_RATE_IDX(mi->max_tp_rate[0]);
529 	max_tp_prob = mi->groups[max_tp_group].rates[max_tp_idx].prob_avg;
530 
531 	if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(index)) &&
532 	    !minstrel_ht_is_legacy_group(max_tp_group))
533 		return;
534 
535 	/* skip rates faster than max tp rate with lower prob */
536 	if (minstrel_get_duration(mi->max_tp_rate[0]) > minstrel_get_duration(index) &&
537 	    mrs->prob_avg < max_tp_prob)
538 		return;
539 
540 	max_gpr_group = MI_RATE_GROUP(mg->max_group_prob_rate);
541 	max_gpr_idx = MI_RATE_IDX(mg->max_group_prob_rate);
542 	max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_avg;
543 
544 	if (mrs->prob_avg > MINSTREL_FRAC(75, 100)) {
545 		cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx,
546 						    mrs->prob_avg);
547 		if (cur_tp_avg > tmp_tp_avg)
548 			*dest = index;
549 
550 		max_gpr_tp_avg = minstrel_ht_get_tp_avg(mi, max_gpr_group,
551 							max_gpr_idx,
552 							max_gpr_prob);
553 		if (cur_tp_avg > max_gpr_tp_avg)
554 			mg->max_group_prob_rate = index;
555 	} else {
556 		if (mrs->prob_avg > tmp_prob)
557 			*dest = index;
558 		if (mrs->prob_avg > max_gpr_prob)
559 			mg->max_group_prob_rate = index;
560 	}
561 }
562 
563 
564 /*
565  * Assign new rate set per sta and use CCK rates only if the fastest
566  * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
567  * rate sets where MCS and CCK rates are mixed, because CCK rates can
568  * not use aggregation.
569  */
570 static void
571 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
572 				 u16 tmp_mcs_tp_rate[MAX_THR_RATES],
573 				 u16 tmp_legacy_tp_rate[MAX_THR_RATES])
574 {
575 	unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob;
576 	int i;
577 
578 	tmp_group = MI_RATE_GROUP(tmp_legacy_tp_rate[0]);
579 	tmp_idx = MI_RATE_IDX(tmp_legacy_tp_rate[0]);
580 	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
581 	tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
582 
583 	tmp_group = MI_RATE_GROUP(tmp_mcs_tp_rate[0]);
584 	tmp_idx = MI_RATE_IDX(tmp_mcs_tp_rate[0]);
585 	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
586 	tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
587 
588 	if (tmp_cck_tp > tmp_mcs_tp) {
589 		for(i = 0; i < MAX_THR_RATES; i++) {
590 			minstrel_ht_sort_best_tp_rates(mi, tmp_legacy_tp_rate[i],
591 						       tmp_mcs_tp_rate);
592 		}
593 	}
594 
595 }
596 
597 /*
598  * Try to increase robustness of max_prob rate by decrease number of
599  * streams if possible.
600  */
601 static inline void
602 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
603 {
604 	struct minstrel_mcs_group_data *mg;
605 	int tmp_max_streams, group, tmp_idx, tmp_prob;
606 	int tmp_tp = 0;
607 
608 	if (!mi->sta->ht_cap.ht_supported)
609 		return;
610 
611 	group = MI_RATE_GROUP(mi->max_tp_rate[0]);
612 	tmp_max_streams = minstrel_mcs_groups[group].streams;
613 	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
614 		mg = &mi->groups[group];
615 		if (!mi->supported[group] || group == MINSTREL_CCK_GROUP)
616 			continue;
617 
618 		tmp_idx = MI_RATE_IDX(mg->max_group_prob_rate);
619 		tmp_prob = mi->groups[group].rates[tmp_idx].prob_avg;
620 
621 		if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx, tmp_prob) &&
622 		   (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
623 				mi->max_prob_rate = mg->max_group_prob_rate;
624 				tmp_tp = minstrel_ht_get_tp_avg(mi, group,
625 								tmp_idx,
626 								tmp_prob);
627 		}
628 	}
629 }
630 
631 static u16
632 __minstrel_ht_get_sample_rate(struct minstrel_ht_sta *mi,
633 			      enum minstrel_sample_type type)
634 {
635 	u16 *rates = mi->sample[type].sample_rates;
636 	u16 cur;
637 	int i;
638 
639 	for (i = 0; i < MINSTREL_SAMPLE_RATES; i++) {
640 		if (!rates[i])
641 			continue;
642 
643 		cur = rates[i];
644 		rates[i] = 0;
645 		return cur;
646 	}
647 
648 	return 0;
649 }
650 
651 static inline int
652 minstrel_ewma(int old, int new, int weight)
653 {
654 	int diff, incr;
655 
656 	diff = new - old;
657 	incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
658 
659 	return old + incr;
660 }
661 
662 static inline int minstrel_filter_avg_add(u16 *prev_1, u16 *prev_2, s32 in)
663 {
664 	s32 out_1 = *prev_1;
665 	s32 out_2 = *prev_2;
666 	s32 val;
667 
668 	if (!in)
669 		in += 1;
670 
671 	if (!out_1) {
672 		val = out_1 = in;
673 		goto out;
674 	}
675 
676 	val = MINSTREL_AVG_COEFF1 * in;
677 	val += MINSTREL_AVG_COEFF2 * out_1;
678 	val += MINSTREL_AVG_COEFF3 * out_2;
679 	val >>= MINSTREL_SCALE;
680 
681 	if (val > 1 << MINSTREL_SCALE)
682 		val = 1 << MINSTREL_SCALE;
683 	if (val < 0)
684 		val = 1;
685 
686 out:
687 	*prev_2 = out_1;
688 	*prev_1 = val;
689 
690 	return val;
691 }
692 
693 /*
694 * Recalculate statistics and counters of a given rate
695 */
696 static void
697 minstrel_ht_calc_rate_stats(struct minstrel_priv *mp,
698 			    struct minstrel_rate_stats *mrs)
699 {
700 	unsigned int cur_prob;
701 
702 	if (unlikely(mrs->attempts > 0)) {
703 		cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
704 		minstrel_filter_avg_add(&mrs->prob_avg,
705 					&mrs->prob_avg_1, cur_prob);
706 		mrs->att_hist += mrs->attempts;
707 		mrs->succ_hist += mrs->success;
708 	}
709 
710 	mrs->last_success = mrs->success;
711 	mrs->last_attempts = mrs->attempts;
712 	mrs->success = 0;
713 	mrs->attempts = 0;
714 }
715 
716 static bool
717 minstrel_ht_find_sample_rate(struct minstrel_ht_sta *mi, int type, int idx)
718 {
719 	int i;
720 
721 	for (i = 0; i < MINSTREL_SAMPLE_RATES; i++) {
722 		u16 cur = mi->sample[type].sample_rates[i];
723 
724 		if (cur == idx)
725 			return true;
726 
727 		if (!cur)
728 			break;
729 	}
730 
731 	return false;
732 }
733 
734 static int
735 minstrel_ht_move_sample_rates(struct minstrel_ht_sta *mi, int type,
736 			      u32 fast_rate_dur, u32 slow_rate_dur)
737 {
738 	u16 *rates = mi->sample[type].sample_rates;
739 	int i, j;
740 
741 	for (i = 0, j = 0; i < MINSTREL_SAMPLE_RATES; i++) {
742 		u32 duration;
743 		bool valid = false;
744 		u16 cur;
745 
746 		cur = rates[i];
747 		if (!cur)
748 			continue;
749 
750 		duration = minstrel_get_duration(cur);
751 		switch (type) {
752 		case MINSTREL_SAMPLE_TYPE_SLOW:
753 			valid = duration > fast_rate_dur &&
754 				duration < slow_rate_dur;
755 			break;
756 		case MINSTREL_SAMPLE_TYPE_INC:
757 		case MINSTREL_SAMPLE_TYPE_JUMP:
758 			valid = duration < fast_rate_dur;
759 			break;
760 		default:
761 			valid = false;
762 			break;
763 		}
764 
765 		if (!valid) {
766 			rates[i] = 0;
767 			continue;
768 		}
769 
770 		if (i == j)
771 			continue;
772 
773 		rates[j++] = cur;
774 		rates[i] = 0;
775 	}
776 
777 	return j;
778 }
779 
780 static int
781 minstrel_ht_group_min_rate_offset(struct minstrel_ht_sta *mi, int group,
782 				  u32 max_duration)
783 {
784 	u16 supported = mi->supported[group];
785 	int i;
786 
787 	for (i = 0; i < MCS_GROUP_RATES && supported; i++, supported >>= 1) {
788 		if (!(supported & BIT(0)))
789 			continue;
790 
791 		if (minstrel_get_duration(MI_RATE(group, i)) >= max_duration)
792 			continue;
793 
794 		return i;
795 	}
796 
797 	return -1;
798 }
799 
800 /*
801  * Incremental update rates:
802  * Flip through groups and pick the first group rate that is faster than the
803  * highest currently selected rate
804  */
805 static u16
806 minstrel_ht_next_inc_rate(struct minstrel_ht_sta *mi, u32 fast_rate_dur)
807 {
808 	u8 type = MINSTREL_SAMPLE_TYPE_INC;
809 	int i, index = 0;
810 	u8 group;
811 
812 	group = mi->sample[type].sample_group;
813 	for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
814 		group = (group + 1) % ARRAY_SIZE(minstrel_mcs_groups);
815 
816 		index = minstrel_ht_group_min_rate_offset(mi, group,
817 							  fast_rate_dur);
818 		if (index < 0)
819 			continue;
820 
821 		index = MI_RATE(group, index & 0xf);
822 		if (!minstrel_ht_find_sample_rate(mi, type, index))
823 			goto out;
824 	}
825 	index = 0;
826 
827 out:
828 	mi->sample[type].sample_group = group;
829 
830 	return index;
831 }
832 
833 static int
834 minstrel_ht_next_group_sample_rate(struct minstrel_ht_sta *mi, int group,
835 				   u16 supported, int offset)
836 {
837 	struct minstrel_mcs_group_data *mg = &mi->groups[group];
838 	u16 idx;
839 	int i;
840 
841 	for (i = 0; i < MCS_GROUP_RATES; i++) {
842 		idx = sample_table[mg->column][mg->index];
843 		if (++mg->index >= MCS_GROUP_RATES) {
844 			mg->index = 0;
845 			if (++mg->column >= ARRAY_SIZE(sample_table))
846 				mg->column = 0;
847 		}
848 
849 		if (idx < offset)
850 			continue;
851 
852 		if (!(supported & BIT(idx)))
853 			continue;
854 
855 		return MI_RATE(group, idx);
856 	}
857 
858 	return -1;
859 }
860 
861 /*
862  * Jump rates:
863  * Sample random rates, use those that are faster than the highest
864  * currently selected rate. Rates between the fastest and the slowest
865  * get sorted into the slow sample bucket, but only if it has room
866  */
867 static u16
868 minstrel_ht_next_jump_rate(struct minstrel_ht_sta *mi, u32 fast_rate_dur,
869 			   u32 slow_rate_dur, int *slow_rate_ofs)
870 {
871 	struct minstrel_rate_stats *mrs;
872 	u32 max_duration = slow_rate_dur;
873 	int i, index, offset;
874 	u16 *slow_rates;
875 	u16 supported;
876 	u32 duration;
877 	u8 group;
878 
879 	if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
880 		max_duration = fast_rate_dur;
881 
882 	slow_rates = mi->sample[MINSTREL_SAMPLE_TYPE_SLOW].sample_rates;
883 	group = mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_group;
884 	for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
885 		u8 type;
886 
887 		group = (group + 1) % ARRAY_SIZE(minstrel_mcs_groups);
888 
889 		supported = mi->supported[group];
890 		if (!supported)
891 			continue;
892 
893 		offset = minstrel_ht_group_min_rate_offset(mi, group,
894 							   max_duration);
895 		if (offset < 0)
896 			continue;
897 
898 		index = minstrel_ht_next_group_sample_rate(mi, group, supported,
899 							   offset);
900 		if (index < 0)
901 			continue;
902 
903 		duration = minstrel_get_duration(index);
904 		if (duration < fast_rate_dur)
905 			type = MINSTREL_SAMPLE_TYPE_JUMP;
906 		else
907 			type = MINSTREL_SAMPLE_TYPE_SLOW;
908 
909 		if (minstrel_ht_find_sample_rate(mi, type, index))
910 			continue;
911 
912 		if (type == MINSTREL_SAMPLE_TYPE_JUMP)
913 			goto found;
914 
915 		if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
916 			continue;
917 
918 		if (duration >= slow_rate_dur)
919 			continue;
920 
921 		/* skip slow rates with high success probability */
922 		mrs = minstrel_get_ratestats(mi, index);
923 		if (mrs->prob_avg > MINSTREL_FRAC(95, 100))
924 			continue;
925 
926 		slow_rates[(*slow_rate_ofs)++] = index;
927 		if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
928 			max_duration = fast_rate_dur;
929 	}
930 	index = 0;
931 
932 found:
933 	mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_group = group;
934 
935 	return index;
936 }
937 
938 static void
939 minstrel_ht_refill_sample_rates(struct minstrel_ht_sta *mi)
940 {
941 	u32 prob_dur = minstrel_get_duration(mi->max_prob_rate);
942 	u32 tp_dur = minstrel_get_duration(mi->max_tp_rate[0]);
943 	u32 tp2_dur = minstrel_get_duration(mi->max_tp_rate[1]);
944 	u32 fast_rate_dur = min(min(tp_dur, tp2_dur), prob_dur);
945 	u32 slow_rate_dur = max(max(tp_dur, tp2_dur), prob_dur);
946 	u16 *rates;
947 	int i, j;
948 
949 	rates = mi->sample[MINSTREL_SAMPLE_TYPE_INC].sample_rates;
950 	i = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_INC,
951 					  fast_rate_dur, slow_rate_dur);
952 	while (i < MINSTREL_SAMPLE_RATES) {
953 		rates[i] = minstrel_ht_next_inc_rate(mi, tp_dur);
954 		if (!rates[i])
955 			break;
956 
957 		i++;
958 	}
959 
960 	rates = mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_rates;
961 	i = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_JUMP,
962 					  fast_rate_dur, slow_rate_dur);
963 	j = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_SLOW,
964 					  fast_rate_dur, slow_rate_dur);
965 	while (i < MINSTREL_SAMPLE_RATES) {
966 		rates[i] = minstrel_ht_next_jump_rate(mi, fast_rate_dur,
967 						      slow_rate_dur, &j);
968 		if (!rates[i])
969 			break;
970 
971 		i++;
972 	}
973 
974 	for (i = 0; i < ARRAY_SIZE(mi->sample); i++)
975 		memcpy(mi->sample[i].cur_sample_rates, mi->sample[i].sample_rates,
976 		       sizeof(mi->sample[i].cur_sample_rates));
977 }
978 
979 
980 /*
981  * Update rate statistics and select new primary rates
982  *
983  * Rules for rate selection:
984  *  - max_prob_rate must use only one stream, as a tradeoff between delivery
985  *    probability and throughput during strong fluctuations
986  *  - as long as the max prob rate has a probability of more than 75%, pick
987  *    higher throughput rates, even if the probablity is a bit lower
988  */
989 static void
990 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
991 {
992 	struct minstrel_mcs_group_data *mg;
993 	struct minstrel_rate_stats *mrs;
994 	int group, i, j, cur_prob;
995 	u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
996 	u16 tmp_legacy_tp_rate[MAX_THR_RATES], tmp_max_prob_rate;
997 	u16 index;
998 	bool ht_supported = mi->sta->ht_cap.ht_supported;
999 
1000 	if (mi->ampdu_packets > 0) {
1001 		if (!ieee80211_hw_check(mp->hw, TX_STATUS_NO_AMPDU_LEN))
1002 			mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
1003 				MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets),
1004 					      EWMA_LEVEL);
1005 		else
1006 			mi->avg_ampdu_len = 0;
1007 		mi->ampdu_len = 0;
1008 		mi->ampdu_packets = 0;
1009 	}
1010 
1011 	if (mi->supported[MINSTREL_CCK_GROUP])
1012 		group = MINSTREL_CCK_GROUP;
1013 	else if (mi->supported[MINSTREL_OFDM_GROUP])
1014 		group = MINSTREL_OFDM_GROUP;
1015 	else
1016 		group = 0;
1017 
1018 	index = MI_RATE(group, 0);
1019 	for (j = 0; j < ARRAY_SIZE(tmp_legacy_tp_rate); j++)
1020 		tmp_legacy_tp_rate[j] = index;
1021 
1022 	if (mi->supported[MINSTREL_VHT_GROUP_0])
1023 		group = MINSTREL_VHT_GROUP_0;
1024 	else if (ht_supported)
1025 		group = MINSTREL_HT_GROUP_0;
1026 	else if (mi->supported[MINSTREL_CCK_GROUP])
1027 		group = MINSTREL_CCK_GROUP;
1028 	else
1029 		group = MINSTREL_OFDM_GROUP;
1030 
1031 	index = MI_RATE(group, 0);
1032 	tmp_max_prob_rate = index;
1033 	for (j = 0; j < ARRAY_SIZE(tmp_mcs_tp_rate); j++)
1034 		tmp_mcs_tp_rate[j] = index;
1035 
1036 	/* Find best rate sets within all MCS groups*/
1037 	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
1038 		u16 *tp_rate = tmp_mcs_tp_rate;
1039 		u16 last_prob = 0;
1040 
1041 		mg = &mi->groups[group];
1042 		if (!mi->supported[group])
1043 			continue;
1044 
1045 		/* (re)Initialize group rate indexes */
1046 		for(j = 0; j < MAX_THR_RATES; j++)
1047 			tmp_group_tp_rate[j] = MI_RATE(group, 0);
1048 
1049 		if (group == MINSTREL_CCK_GROUP && ht_supported)
1050 			tp_rate = tmp_legacy_tp_rate;
1051 
1052 		for (i = MCS_GROUP_RATES - 1; i >= 0; i--) {
1053 			if (!(mi->supported[group] & BIT(i)))
1054 				continue;
1055 
1056 			index = MI_RATE(group, i);
1057 
1058 			mrs = &mg->rates[i];
1059 			mrs->retry_updated = false;
1060 			minstrel_ht_calc_rate_stats(mp, mrs);
1061 
1062 			if (mrs->att_hist)
1063 				last_prob = max(last_prob, mrs->prob_avg);
1064 			else
1065 				mrs->prob_avg = max(last_prob, mrs->prob_avg);
1066 			cur_prob = mrs->prob_avg;
1067 
1068 			if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
1069 				continue;
1070 
1071 			/* Find max throughput rate set */
1072 			minstrel_ht_sort_best_tp_rates(mi, index, tp_rate);
1073 
1074 			/* Find max throughput rate set within a group */
1075 			minstrel_ht_sort_best_tp_rates(mi, index,
1076 						       tmp_group_tp_rate);
1077 		}
1078 
1079 		memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
1080 		       sizeof(mg->max_group_tp_rate));
1081 	}
1082 
1083 	/* Assign new rate set per sta */
1084 	minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate,
1085 					 tmp_legacy_tp_rate);
1086 	memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
1087 
1088 	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
1089 		if (!mi->supported[group])
1090 			continue;
1091 
1092 		mg = &mi->groups[group];
1093 		mg->max_group_prob_rate = MI_RATE(group, 0);
1094 
1095 		for (i = 0; i < MCS_GROUP_RATES; i++) {
1096 			if (!(mi->supported[group] & BIT(i)))
1097 				continue;
1098 
1099 			index = MI_RATE(group, i);
1100 
1101 			/* Find max probability rate per group and global */
1102 			minstrel_ht_set_best_prob_rate(mi, &tmp_max_prob_rate,
1103 						       index);
1104 		}
1105 	}
1106 
1107 	mi->max_prob_rate = tmp_max_prob_rate;
1108 
1109 	/* Try to increase robustness of max_prob_rate*/
1110 	minstrel_ht_prob_rate_reduce_streams(mi);
1111 	minstrel_ht_refill_sample_rates(mi);
1112 
1113 #ifdef CONFIG_MAC80211_DEBUGFS
1114 	/* use fixed index if set */
1115 	if (mp->fixed_rate_idx != -1) {
1116 		for (i = 0; i < 4; i++)
1117 			mi->max_tp_rate[i] = mp->fixed_rate_idx;
1118 		mi->max_prob_rate = mp->fixed_rate_idx;
1119 	}
1120 #endif
1121 
1122 	/* Reset update timer */
1123 	mi->last_stats_update = jiffies;
1124 	mi->sample_time = jiffies;
1125 }
1126 
1127 static bool
1128 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1129 			 struct ieee80211_tx_rate *rate)
1130 {
1131 	int i;
1132 
1133 	if (rate->idx < 0)
1134 		return false;
1135 
1136 	if (!rate->count)
1137 		return false;
1138 
1139 	if (rate->flags & IEEE80211_TX_RC_MCS ||
1140 	    rate->flags & IEEE80211_TX_RC_VHT_MCS)
1141 		return true;
1142 
1143 	for (i = 0; i < ARRAY_SIZE(mp->cck_rates); i++)
1144 		if (rate->idx == mp->cck_rates[i])
1145 			return true;
1146 
1147 	for (i = 0; i < ARRAY_SIZE(mp->ofdm_rates[0]); i++)
1148 		if (rate->idx == mp->ofdm_rates[mi->band][i])
1149 			return true;
1150 
1151 	return false;
1152 }
1153 
1154 static void
1155 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u16 *idx, bool primary)
1156 {
1157 	int group, orig_group;
1158 
1159 	orig_group = group = MI_RATE_GROUP(*idx);
1160 	while (group > 0) {
1161 		group--;
1162 
1163 		if (!mi->supported[group])
1164 			continue;
1165 
1166 		if (minstrel_mcs_groups[group].streams >
1167 		    minstrel_mcs_groups[orig_group].streams)
1168 			continue;
1169 
1170 		if (primary)
1171 			*idx = mi->groups[group].max_group_tp_rate[0];
1172 		else
1173 			*idx = mi->groups[group].max_group_tp_rate[1];
1174 		break;
1175 	}
1176 }
1177 
1178 static void
1179 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
1180 {
1181 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1182 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
1183 	u16 tid;
1184 
1185 	if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
1186 		return;
1187 
1188 	if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
1189 		return;
1190 
1191 	if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
1192 		return;
1193 
1194 	tid = ieee80211_get_tid(hdr);
1195 	if (likely(sta->ampdu_mlme.tid_tx[tid]))
1196 		return;
1197 
1198 	ieee80211_start_tx_ba_session(pubsta, tid, 0);
1199 }
1200 
1201 static void
1202 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
1203                       void *priv_sta, struct ieee80211_tx_status *st)
1204 {
1205 	struct ieee80211_tx_info *info = st->info;
1206 	struct minstrel_ht_sta *mi = priv_sta;
1207 	struct ieee80211_tx_rate *ar = info->status.rates;
1208 	struct minstrel_rate_stats *rate, *rate2;
1209 	struct minstrel_priv *mp = priv;
1210 	u32 update_interval = mp->update_interval;
1211 	bool last, update = false;
1212 	int i;
1213 
1214 	/* This packet was aggregated but doesn't carry status info */
1215 	if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
1216 	    !(info->flags & IEEE80211_TX_STAT_AMPDU))
1217 		return;
1218 
1219 	if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
1220 		info->status.ampdu_ack_len =
1221 			(info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
1222 		info->status.ampdu_len = 1;
1223 	}
1224 
1225 	/* wraparound */
1226 	if (mi->total_packets >= ~0 - info->status.ampdu_len) {
1227 		mi->total_packets = 0;
1228 		mi->sample_packets = 0;
1229 	}
1230 
1231 	mi->total_packets += info->status.ampdu_len;
1232 	if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
1233 		mi->sample_packets += info->status.ampdu_len;
1234 
1235 	mi->ampdu_packets++;
1236 	mi->ampdu_len += info->status.ampdu_len;
1237 
1238 	last = !minstrel_ht_txstat_valid(mp, mi, &ar[0]);
1239 	for (i = 0; !last; i++) {
1240 		last = (i == IEEE80211_TX_MAX_RATES - 1) ||
1241 		       !minstrel_ht_txstat_valid(mp, mi, &ar[i + 1]);
1242 
1243 		rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
1244 		if (last)
1245 			rate->success += info->status.ampdu_ack_len;
1246 
1247 		rate->attempts += ar[i].count * info->status.ampdu_len;
1248 	}
1249 
1250 	if (mp->hw->max_rates > 1) {
1251 		/*
1252 		 * check for sudden death of spatial multiplexing,
1253 		 * downgrade to a lower number of streams if necessary.
1254 		 */
1255 		rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
1256 		if (rate->attempts > 30 &&
1257 		    rate->success < rate->attempts / 4) {
1258 			minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
1259 			update = true;
1260 		}
1261 
1262 		rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
1263 		if (rate2->attempts > 30 &&
1264 		    rate2->success < rate2->attempts / 4) {
1265 			minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
1266 			update = true;
1267 		}
1268 	}
1269 
1270 	if (time_after(jiffies, mi->last_stats_update + update_interval)) {
1271 		update = true;
1272 		minstrel_ht_update_stats(mp, mi);
1273 	}
1274 
1275 	if (update)
1276 		minstrel_ht_update_rates(mp, mi);
1277 }
1278 
1279 static void
1280 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1281                          int index)
1282 {
1283 	struct minstrel_rate_stats *mrs;
1284 	unsigned int tx_time, tx_time_rtscts, tx_time_data;
1285 	unsigned int cw = mp->cw_min;
1286 	unsigned int ctime = 0;
1287 	unsigned int t_slot = 9; /* FIXME */
1288 	unsigned int ampdu_len = minstrel_ht_avg_ampdu_len(mi);
1289 	unsigned int overhead = 0, overhead_rtscts = 0;
1290 
1291 	mrs = minstrel_get_ratestats(mi, index);
1292 	if (mrs->prob_avg < MINSTREL_FRAC(1, 10)) {
1293 		mrs->retry_count = 1;
1294 		mrs->retry_count_rtscts = 1;
1295 		return;
1296 	}
1297 
1298 	mrs->retry_count = 2;
1299 	mrs->retry_count_rtscts = 2;
1300 	mrs->retry_updated = true;
1301 
1302 	tx_time_data = minstrel_get_duration(index) * ampdu_len / 1000;
1303 
1304 	/* Contention time for first 2 tries */
1305 	ctime = (t_slot * cw) >> 1;
1306 	cw = min((cw << 1) | 1, mp->cw_max);
1307 	ctime += (t_slot * cw) >> 1;
1308 	cw = min((cw << 1) | 1, mp->cw_max);
1309 
1310 	if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(index))) {
1311 		overhead = mi->overhead_legacy;
1312 		overhead_rtscts = mi->overhead_legacy_rtscts;
1313 	} else {
1314 		overhead = mi->overhead;
1315 		overhead_rtscts = mi->overhead_rtscts;
1316 	}
1317 
1318 	/* Total TX time for data and Contention after first 2 tries */
1319 	tx_time = ctime + 2 * (overhead + tx_time_data);
1320 	tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
1321 
1322 	/* See how many more tries we can fit inside segment size */
1323 	do {
1324 		/* Contention time for this try */
1325 		ctime = (t_slot * cw) >> 1;
1326 		cw = min((cw << 1) | 1, mp->cw_max);
1327 
1328 		/* Total TX time after this try */
1329 		tx_time += ctime + overhead + tx_time_data;
1330 		tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
1331 
1332 		if (tx_time_rtscts < mp->segment_size)
1333 			mrs->retry_count_rtscts++;
1334 	} while ((tx_time < mp->segment_size) &&
1335 	         (++mrs->retry_count < mp->max_retry));
1336 }
1337 
1338 
1339 static void
1340 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1341                      struct ieee80211_sta_rates *ratetbl, int offset, int index)
1342 {
1343 	int group_idx = MI_RATE_GROUP(index);
1344 	const struct mcs_group *group = &minstrel_mcs_groups[group_idx];
1345 	struct minstrel_rate_stats *mrs;
1346 	u8 idx;
1347 	u16 flags = group->flags;
1348 
1349 	mrs = minstrel_get_ratestats(mi, index);
1350 	if (!mrs->retry_updated)
1351 		minstrel_calc_retransmit(mp, mi, index);
1352 
1353 	if (mrs->prob_avg < MINSTREL_FRAC(20, 100) || !mrs->retry_count) {
1354 		ratetbl->rate[offset].count = 2;
1355 		ratetbl->rate[offset].count_rts = 2;
1356 		ratetbl->rate[offset].count_cts = 2;
1357 	} else {
1358 		ratetbl->rate[offset].count = mrs->retry_count;
1359 		ratetbl->rate[offset].count_cts = mrs->retry_count;
1360 		ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
1361 	}
1362 
1363 	index = MI_RATE_IDX(index);
1364 	if (group_idx == MINSTREL_CCK_GROUP)
1365 		idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
1366 	else if (group_idx == MINSTREL_OFDM_GROUP)
1367 		idx = mp->ofdm_rates[mi->band][index %
1368 					       ARRAY_SIZE(mp->ofdm_rates[0])];
1369 	else if (flags & IEEE80211_TX_RC_VHT_MCS)
1370 		idx = ((group->streams - 1) << 4) |
1371 		      (index & 0xF);
1372 	else
1373 		idx = index + (group->streams - 1) * 8;
1374 
1375 	/* enable RTS/CTS if needed:
1376 	 *  - if station is in dynamic SMPS (and streams > 1)
1377 	 *  - for fallback rates, to increase chances of getting through
1378 	 */
1379 	if (offset > 0 ||
1380 	    (mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
1381 	     group->streams > 1)) {
1382 		ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
1383 		flags |= IEEE80211_TX_RC_USE_RTS_CTS;
1384 	}
1385 
1386 	ratetbl->rate[offset].idx = idx;
1387 	ratetbl->rate[offset].flags = flags;
1388 }
1389 
1390 static inline int
1391 minstrel_ht_get_prob_avg(struct minstrel_ht_sta *mi, int rate)
1392 {
1393 	int group = MI_RATE_GROUP(rate);
1394 	rate = MI_RATE_IDX(rate);
1395 	return mi->groups[group].rates[rate].prob_avg;
1396 }
1397 
1398 static int
1399 minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
1400 {
1401 	int group = MI_RATE_GROUP(mi->max_prob_rate);
1402 	const struct mcs_group *g = &minstrel_mcs_groups[group];
1403 	int rate = MI_RATE_IDX(mi->max_prob_rate);
1404 	unsigned int duration;
1405 
1406 	/* Disable A-MSDU if max_prob_rate is bad */
1407 	if (mi->groups[group].rates[rate].prob_avg < MINSTREL_FRAC(50, 100))
1408 		return 1;
1409 
1410 	duration = g->duration[rate];
1411 	duration <<= g->shift;
1412 
1413 	/* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
1414 	if (duration > MCS_DURATION(1, 0, 52))
1415 		return 500;
1416 
1417 	/*
1418 	 * If the rate is slower than single-stream MCS4, limit A-MSDU to usual
1419 	 * data packet size
1420 	 */
1421 	if (duration > MCS_DURATION(1, 0, 104))
1422 		return 1600;
1423 
1424 	/*
1425 	 * If the rate is slower than single-stream MCS7, or if the max throughput
1426 	 * rate success probability is less than 75%, limit A-MSDU to twice the usual
1427 	 * data packet size
1428 	 */
1429 	if (duration > MCS_DURATION(1, 0, 260) ||
1430 	    (minstrel_ht_get_prob_avg(mi, mi->max_tp_rate[0]) <
1431 	     MINSTREL_FRAC(75, 100)))
1432 		return 3200;
1433 
1434 	/*
1435 	 * HT A-MPDU limits maximum MPDU size under BA agreement to 4095 bytes.
1436 	 * Since aggregation sessions are started/stopped without txq flush, use
1437 	 * the limit here to avoid the complexity of having to de-aggregate
1438 	 * packets in the queue.
1439 	 */
1440 	if (!mi->sta->vht_cap.vht_supported)
1441 		return IEEE80211_MAX_MPDU_LEN_HT_BA;
1442 
1443 	/* unlimited */
1444 	return 0;
1445 }
1446 
1447 static void
1448 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
1449 {
1450 	struct ieee80211_sta_rates *rates;
1451 	int i = 0;
1452 
1453 	rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
1454 	if (!rates)
1455 		return;
1456 
1457 	/* Start with max_tp_rate[0] */
1458 	minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
1459 
1460 	if (mp->hw->max_rates >= 3) {
1461 		/* At least 3 tx rates supported, use max_tp_rate[1] next */
1462 		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
1463 	}
1464 
1465 	if (mp->hw->max_rates >= 2) {
1466 		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
1467 	}
1468 
1469 	mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi);
1470 	rates->rate[i].idx = -1;
1471 	rate_control_set_rates(mp->hw, mi->sta, rates);
1472 }
1473 
1474 static u16
1475 minstrel_ht_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
1476 {
1477 	u8 seq;
1478 
1479 	if (mp->hw->max_rates > 1) {
1480 		seq = mi->sample_seq;
1481 		mi->sample_seq = (seq + 1) % ARRAY_SIZE(minstrel_sample_seq);
1482 		seq = minstrel_sample_seq[seq];
1483 	} else {
1484 		seq = MINSTREL_SAMPLE_TYPE_INC;
1485 	}
1486 
1487 	return __minstrel_ht_get_sample_rate(mi, seq);
1488 }
1489 
1490 static void
1491 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
1492                      struct ieee80211_tx_rate_control *txrc)
1493 {
1494 	const struct mcs_group *sample_group;
1495 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
1496 	struct ieee80211_tx_rate *rate = &info->status.rates[0];
1497 	struct minstrel_ht_sta *mi = priv_sta;
1498 	struct minstrel_priv *mp = priv;
1499 	u16 sample_idx;
1500 
1501 	if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
1502 	    !minstrel_ht_is_legacy_group(MI_RATE_GROUP(mi->max_prob_rate)))
1503 		minstrel_aggr_check(sta, txrc->skb);
1504 
1505 	info->flags |= mi->tx_flags;
1506 
1507 #ifdef CONFIG_MAC80211_DEBUGFS
1508 	if (mp->fixed_rate_idx != -1)
1509 		return;
1510 #endif
1511 
1512 	/* Don't use EAPOL frames for sampling on non-mrr hw */
1513 	if (mp->hw->max_rates == 1 &&
1514 	    (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
1515 		return;
1516 
1517 	if (time_is_before_jiffies(mi->sample_time))
1518 		return;
1519 
1520 	mi->sample_time = jiffies + MINSTREL_SAMPLE_INTERVAL;
1521 	sample_idx = minstrel_ht_get_sample_rate(mp, mi);
1522 	if (!sample_idx)
1523 		return;
1524 
1525 	sample_group = &minstrel_mcs_groups[MI_RATE_GROUP(sample_idx)];
1526 	sample_idx = MI_RATE_IDX(sample_idx);
1527 
1528 	if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP] &&
1529 	    (sample_idx >= 4) != txrc->short_preamble)
1530 		return;
1531 
1532 	info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
1533 	rate->count = 1;
1534 
1535 	if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP]) {
1536 		int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
1537 		rate->idx = mp->cck_rates[idx];
1538 	} else if (sample_group == &minstrel_mcs_groups[MINSTREL_OFDM_GROUP]) {
1539 		int idx = sample_idx % ARRAY_SIZE(mp->ofdm_rates[0]);
1540 		rate->idx = mp->ofdm_rates[mi->band][idx];
1541 	} else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
1542 		ieee80211_rate_set_vht(rate, MI_RATE_IDX(sample_idx),
1543 				       sample_group->streams);
1544 	} else {
1545 		rate->idx = sample_idx + (sample_group->streams - 1) * 8;
1546 	}
1547 
1548 	rate->flags = sample_group->flags;
1549 }
1550 
1551 static void
1552 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1553 		       struct ieee80211_supported_band *sband,
1554 		       struct ieee80211_sta *sta)
1555 {
1556 	int i;
1557 
1558 	if (sband->band != NL80211_BAND_2GHZ)
1559 		return;
1560 
1561 	if (sta->ht_cap.ht_supported &&
1562 	    !ieee80211_hw_check(mp->hw, SUPPORTS_HT_CCK_RATES))
1563 		return;
1564 
1565 	for (i = 0; i < 4; i++) {
1566 		if (mp->cck_rates[i] == 0xff ||
1567 		    !rate_supported(sta, sband->band, mp->cck_rates[i]))
1568 			continue;
1569 
1570 		mi->supported[MINSTREL_CCK_GROUP] |= BIT(i);
1571 		if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
1572 			mi->supported[MINSTREL_CCK_GROUP] |= BIT(i + 4);
1573 	}
1574 }
1575 
1576 static void
1577 minstrel_ht_update_ofdm(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1578 			struct ieee80211_supported_band *sband,
1579 			struct ieee80211_sta *sta)
1580 {
1581 	const u8 *rates;
1582 	int i;
1583 
1584 	if (sta->ht_cap.ht_supported)
1585 		return;
1586 
1587 	rates = mp->ofdm_rates[sband->band];
1588 	for (i = 0; i < ARRAY_SIZE(mp->ofdm_rates[0]); i++) {
1589 		if (rates[i] == 0xff ||
1590 		    !rate_supported(sta, sband->band, rates[i]))
1591 			continue;
1592 
1593 		mi->supported[MINSTREL_OFDM_GROUP] |= BIT(i);
1594 	}
1595 }
1596 
1597 static void
1598 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
1599 			struct cfg80211_chan_def *chandef,
1600 			struct ieee80211_sta *sta, void *priv_sta)
1601 {
1602 	struct minstrel_priv *mp = priv;
1603 	struct minstrel_ht_sta *mi = priv_sta;
1604 	struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
1605 	u16 ht_cap = sta->ht_cap.cap;
1606 	struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
1607 	const struct ieee80211_rate *ctl_rate;
1608 	bool ldpc, erp;
1609 	int use_vht;
1610 	int n_supported = 0;
1611 	int ack_dur;
1612 	int stbc;
1613 	int i;
1614 
1615 	BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);
1616 
1617 	if (vht_cap->vht_supported)
1618 		use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
1619 	else
1620 		use_vht = 0;
1621 
1622 	memset(mi, 0, sizeof(*mi));
1623 
1624 	mi->sta = sta;
1625 	mi->band = sband->band;
1626 	mi->last_stats_update = jiffies;
1627 
1628 	ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
1629 	mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
1630 	mi->overhead += ack_dur;
1631 	mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
1632 
1633 	ctl_rate = &sband->bitrates[rate_lowest_index(sband, sta)];
1634 	erp = ctl_rate->flags & IEEE80211_RATE_ERP_G;
1635 	ack_dur = ieee80211_frame_duration(sband->band, 10,
1636 					   ctl_rate->bitrate, erp, 1,
1637 					   ieee80211_chandef_get_shift(chandef));
1638 	mi->overhead_legacy = ack_dur;
1639 	mi->overhead_legacy_rtscts = mi->overhead_legacy + 2 * ack_dur;
1640 
1641 	mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
1642 
1643 	if (!use_vht) {
1644 		stbc = (ht_cap & IEEE80211_HT_CAP_RX_STBC) >>
1645 			IEEE80211_HT_CAP_RX_STBC_SHIFT;
1646 
1647 		ldpc = ht_cap & IEEE80211_HT_CAP_LDPC_CODING;
1648 	} else {
1649 		stbc = (vht_cap->cap & IEEE80211_VHT_CAP_RXSTBC_MASK) >>
1650 			IEEE80211_VHT_CAP_RXSTBC_SHIFT;
1651 
1652 		ldpc = vht_cap->cap & IEEE80211_VHT_CAP_RXLDPC;
1653 	}
1654 
1655 	mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
1656 	if (ldpc)
1657 		mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
1658 
1659 	for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
1660 		u32 gflags = minstrel_mcs_groups[i].flags;
1661 		int bw, nss;
1662 
1663 		mi->supported[i] = 0;
1664 		if (minstrel_ht_is_legacy_group(i))
1665 			continue;
1666 
1667 		if (gflags & IEEE80211_TX_RC_SHORT_GI) {
1668 			if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
1669 				if (!(ht_cap & IEEE80211_HT_CAP_SGI_40))
1670 					continue;
1671 			} else {
1672 				if (!(ht_cap & IEEE80211_HT_CAP_SGI_20))
1673 					continue;
1674 			}
1675 		}
1676 
1677 		if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
1678 		    sta->bandwidth < IEEE80211_STA_RX_BW_40)
1679 			continue;
1680 
1681 		nss = minstrel_mcs_groups[i].streams;
1682 
1683 		/* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1684 		if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1)
1685 			continue;
1686 
1687 		/* HT rate */
1688 		if (gflags & IEEE80211_TX_RC_MCS) {
1689 			if (use_vht && minstrel_vht_only)
1690 				continue;
1691 
1692 			mi->supported[i] = mcs->rx_mask[nss - 1];
1693 			if (mi->supported[i])
1694 				n_supported++;
1695 			continue;
1696 		}
1697 
1698 		/* VHT rate */
1699 		if (!vht_cap->vht_supported ||
1700 		    WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) ||
1701 		    WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH))
1702 			continue;
1703 
1704 		if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) {
1705 			if (sta->bandwidth < IEEE80211_STA_RX_BW_80 ||
1706 			    ((gflags & IEEE80211_TX_RC_SHORT_GI) &&
1707 			     !(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) {
1708 				continue;
1709 			}
1710 		}
1711 
1712 		if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
1713 			bw = BW_40;
1714 		else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
1715 			bw = BW_80;
1716 		else
1717 			bw = BW_20;
1718 
1719 		mi->supported[i] = minstrel_get_valid_vht_rates(bw, nss,
1720 				vht_cap->vht_mcs.tx_mcs_map);
1721 
1722 		if (mi->supported[i])
1723 			n_supported++;
1724 	}
1725 
1726 	minstrel_ht_update_cck(mp, mi, sband, sta);
1727 	minstrel_ht_update_ofdm(mp, mi, sband, sta);
1728 
1729 	/* create an initial rate table with the lowest supported rates */
1730 	minstrel_ht_update_stats(mp, mi);
1731 	minstrel_ht_update_rates(mp, mi);
1732 }
1733 
1734 static void
1735 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
1736 		      struct cfg80211_chan_def *chandef,
1737                       struct ieee80211_sta *sta, void *priv_sta)
1738 {
1739 	minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1740 }
1741 
1742 static void
1743 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
1744 			struct cfg80211_chan_def *chandef,
1745                         struct ieee80211_sta *sta, void *priv_sta,
1746                         u32 changed)
1747 {
1748 	minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1749 }
1750 
1751 static void *
1752 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
1753 {
1754 	struct ieee80211_supported_band *sband;
1755 	struct minstrel_ht_sta *mi;
1756 	struct minstrel_priv *mp = priv;
1757 	struct ieee80211_hw *hw = mp->hw;
1758 	int max_rates = 0;
1759 	int i;
1760 
1761 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1762 		sband = hw->wiphy->bands[i];
1763 		if (sband && sband->n_bitrates > max_rates)
1764 			max_rates = sband->n_bitrates;
1765 	}
1766 
1767 	return kzalloc(sizeof(*mi), gfp);
1768 }
1769 
1770 static void
1771 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1772 {
1773 	kfree(priv_sta);
1774 }
1775 
1776 static void
1777 minstrel_ht_fill_rate_array(u8 *dest, struct ieee80211_supported_band *sband,
1778 			    const s16 *bitrates, int n_rates, u32 rate_flags)
1779 {
1780 	int i, j;
1781 
1782 	for (i = 0; i < sband->n_bitrates; i++) {
1783 		struct ieee80211_rate *rate = &sband->bitrates[i];
1784 
1785 		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
1786 			continue;
1787 
1788 		for (j = 0; j < n_rates; j++) {
1789 			if (rate->bitrate != bitrates[j])
1790 				continue;
1791 
1792 			dest[j] = i;
1793 			break;
1794 		}
1795 	}
1796 }
1797 
1798 static void
1799 minstrel_ht_init_cck_rates(struct minstrel_priv *mp)
1800 {
1801 	static const s16 bitrates[4] = { 10, 20, 55, 110 };
1802 	struct ieee80211_supported_band *sband;
1803 	u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
1804 
1805 	memset(mp->cck_rates, 0xff, sizeof(mp->cck_rates));
1806 	sband = mp->hw->wiphy->bands[NL80211_BAND_2GHZ];
1807 	if (!sband)
1808 		return;
1809 
1810 	BUILD_BUG_ON(ARRAY_SIZE(mp->cck_rates) != ARRAY_SIZE(bitrates));
1811 	minstrel_ht_fill_rate_array(mp->cck_rates, sband,
1812 				    minstrel_cck_bitrates,
1813 				    ARRAY_SIZE(minstrel_cck_bitrates),
1814 				    rate_flags);
1815 }
1816 
1817 static void
1818 minstrel_ht_init_ofdm_rates(struct minstrel_priv *mp, enum nl80211_band band)
1819 {
1820 	static const s16 bitrates[8] = { 60, 90, 120, 180, 240, 360, 480, 540 };
1821 	struct ieee80211_supported_band *sband;
1822 	u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
1823 
1824 	memset(mp->ofdm_rates[band], 0xff, sizeof(mp->ofdm_rates[band]));
1825 	sband = mp->hw->wiphy->bands[band];
1826 	if (!sband)
1827 		return;
1828 
1829 	BUILD_BUG_ON(ARRAY_SIZE(mp->ofdm_rates[band]) != ARRAY_SIZE(bitrates));
1830 	minstrel_ht_fill_rate_array(mp->ofdm_rates[band], sband,
1831 				    minstrel_ofdm_bitrates,
1832 				    ARRAY_SIZE(minstrel_ofdm_bitrates),
1833 				    rate_flags);
1834 }
1835 
1836 static void *
1837 minstrel_ht_alloc(struct ieee80211_hw *hw)
1838 {
1839 	struct minstrel_priv *mp;
1840 	int i;
1841 
1842 	mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
1843 	if (!mp)
1844 		return NULL;
1845 
1846 	/* contention window settings
1847 	 * Just an approximation. Using the per-queue values would complicate
1848 	 * the calculations and is probably unnecessary */
1849 	mp->cw_min = 15;
1850 	mp->cw_max = 1023;
1851 
1852 	/* maximum time that the hw is allowed to stay in one MRR segment */
1853 	mp->segment_size = 6000;
1854 
1855 	if (hw->max_rate_tries > 0)
1856 		mp->max_retry = hw->max_rate_tries;
1857 	else
1858 		/* safe default, does not necessarily have to match hw properties */
1859 		mp->max_retry = 7;
1860 
1861 	if (hw->max_rates >= 4)
1862 		mp->has_mrr = true;
1863 
1864 	mp->hw = hw;
1865 	mp->update_interval = HZ / 20;
1866 
1867 	minstrel_ht_init_cck_rates(mp);
1868 	for (i = 0; i < ARRAY_SIZE(mp->hw->wiphy->bands); i++)
1869 	    minstrel_ht_init_ofdm_rates(mp, i);
1870 
1871 	return mp;
1872 }
1873 
1874 #ifdef CONFIG_MAC80211_DEBUGFS
1875 static void minstrel_ht_add_debugfs(struct ieee80211_hw *hw, void *priv,
1876 				    struct dentry *debugfsdir)
1877 {
1878 	struct minstrel_priv *mp = priv;
1879 
1880 	mp->fixed_rate_idx = (u32) -1;
1881 	debugfs_create_u32("fixed_rate_idx", S_IRUGO | S_IWUGO, debugfsdir,
1882 			   &mp->fixed_rate_idx);
1883 }
1884 #endif
1885 
1886 static void
1887 minstrel_ht_free(void *priv)
1888 {
1889 	kfree(priv);
1890 }
1891 
1892 static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1893 {
1894 	struct minstrel_ht_sta *mi = priv_sta;
1895 	int i, j, prob, tp_avg;
1896 
1897 	i = MI_RATE_GROUP(mi->max_tp_rate[0]);
1898 	j = MI_RATE_IDX(mi->max_tp_rate[0]);
1899 	prob = mi->groups[i].rates[j].prob_avg;
1900 
1901 	/* convert tp_avg from pkt per second in kbps */
1902 	tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * 10;
1903 	tp_avg = tp_avg * AVG_PKT_SIZE * 8 / 1024;
1904 
1905 	return tp_avg;
1906 }
1907 
1908 static const struct rate_control_ops mac80211_minstrel_ht = {
1909 	.name = "minstrel_ht",
1910 	.tx_status_ext = minstrel_ht_tx_status,
1911 	.get_rate = minstrel_ht_get_rate,
1912 	.rate_init = minstrel_ht_rate_init,
1913 	.rate_update = minstrel_ht_rate_update,
1914 	.alloc_sta = minstrel_ht_alloc_sta,
1915 	.free_sta = minstrel_ht_free_sta,
1916 	.alloc = minstrel_ht_alloc,
1917 	.free = minstrel_ht_free,
1918 #ifdef CONFIG_MAC80211_DEBUGFS
1919 	.add_debugfs = minstrel_ht_add_debugfs,
1920 	.add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1921 #endif
1922 	.get_expected_throughput = minstrel_ht_get_expected_throughput,
1923 };
1924 
1925 
1926 static void __init init_sample_table(void)
1927 {
1928 	int col, i, new_idx;
1929 	u8 rnd[MCS_GROUP_RATES];
1930 
1931 	memset(sample_table, 0xff, sizeof(sample_table));
1932 	for (col = 0; col < SAMPLE_COLUMNS; col++) {
1933 		prandom_bytes(rnd, sizeof(rnd));
1934 		for (i = 0; i < MCS_GROUP_RATES; i++) {
1935 			new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1936 			while (sample_table[col][new_idx] != 0xff)
1937 				new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1938 
1939 			sample_table[col][new_idx] = i;
1940 		}
1941 	}
1942 }
1943 
1944 int __init
1945 rc80211_minstrel_init(void)
1946 {
1947 	init_sample_table();
1948 	return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1949 }
1950 
1951 void
1952 rc80211_minstrel_exit(void)
1953 {
1954 	ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1955 }
1956