1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
4  */
5 #include <linux/netdevice.h>
6 #include <linux/types.h>
7 #include <linux/skbuff.h>
8 #include <linux/debugfs.h>
9 #include <linux/random.h>
10 #include <linux/moduleparam.h>
11 #include <linux/ieee80211.h>
12 #include <net/mac80211.h>
13 #include "rate.h"
14 #include "sta_info.h"
15 #include "rc80211_minstrel.h"
16 #include "rc80211_minstrel_ht.h"
17 
18 #define AVG_AMPDU_SIZE	16
19 #define AVG_PKT_SIZE	1200
20 
21 /* Number of bits for an average sized packet */
22 #define MCS_NBITS ((AVG_PKT_SIZE * AVG_AMPDU_SIZE) << 3)
23 
24 /* Number of symbols for a packet with (bps) bits per symbol */
25 #define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
26 
27 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
28 #define MCS_SYMBOL_TIME(sgi, syms)					\
29 	(sgi ?								\
30 	  ((syms) * 18000 + 4000) / 5 :	/* syms * 3.6 us */		\
31 	  ((syms) * 1000) << 2		/* syms * 4 us */		\
32 	)
33 
34 /* Transmit duration for the raw data part of an average sized packet */
35 #define MCS_DURATION(streams, sgi, bps) \
36 	(MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) / AVG_AMPDU_SIZE)
37 
38 #define BW_20			0
39 #define BW_40			1
40 #define BW_80			2
41 
42 /*
43  * Define group sort order: HT40 -> SGI -> #streams
44  */
45 #define GROUP_IDX(_streams, _sgi, _ht40)	\
46 	MINSTREL_HT_GROUP_0 +			\
47 	MINSTREL_MAX_STREAMS * 2 * _ht40 +	\
48 	MINSTREL_MAX_STREAMS * _sgi +	\
49 	_streams - 1
50 
51 #define _MAX(a, b) (((a)>(b))?(a):(b))
52 
53 #define GROUP_SHIFT(duration)						\
54 	_MAX(0, 16 - __builtin_clz(duration))
55 
56 /* MCS rate information for an MCS group */
57 #define __MCS_GROUP(_streams, _sgi, _ht40, _s)				\
58 	[GROUP_IDX(_streams, _sgi, _ht40)] = {				\
59 	.streams = _streams,						\
60 	.shift = _s,							\
61 	.flags =							\
62 		IEEE80211_TX_RC_MCS |					\
63 		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
64 		(_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),		\
65 	.duration = {							\
66 		MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26) >> _s,	\
67 		MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52) >> _s,	\
68 		MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78) >> _s,	\
69 		MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104) >> _s,	\
70 		MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156) >> _s,	\
71 		MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208) >> _s,	\
72 		MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234) >> _s,	\
73 		MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) >> _s	\
74 	}								\
75 }
76 
77 #define MCS_GROUP_SHIFT(_streams, _sgi, _ht40)				\
78 	GROUP_SHIFT(MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26))
79 
80 #define MCS_GROUP(_streams, _sgi, _ht40)				\
81 	__MCS_GROUP(_streams, _sgi, _ht40,				\
82 		    MCS_GROUP_SHIFT(_streams, _sgi, _ht40))
83 
84 #define VHT_GROUP_IDX(_streams, _sgi, _bw)				\
85 	(MINSTREL_VHT_GROUP_0 +						\
86 	 MINSTREL_MAX_STREAMS * 2 * (_bw) +				\
87 	 MINSTREL_MAX_STREAMS * (_sgi) +				\
88 	 (_streams) - 1)
89 
90 #define BW2VBPS(_bw, r3, r2, r1)					\
91 	(_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
92 
93 #define __VHT_GROUP(_streams, _sgi, _bw, _s)				\
94 	[VHT_GROUP_IDX(_streams, _sgi, _bw)] = {			\
95 	.streams = _streams,						\
96 	.shift = _s,							\
97 	.flags =							\
98 		IEEE80211_TX_RC_VHT_MCS |				\
99 		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
100 		(_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH :		\
101 		 _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),	\
102 	.duration = {							\
103 		MCS_DURATION(_streams, _sgi,				\
104 			     BW2VBPS(_bw,  117,  54,  26)) >> _s,	\
105 		MCS_DURATION(_streams, _sgi,				\
106 			     BW2VBPS(_bw,  234, 108,  52)) >> _s,	\
107 		MCS_DURATION(_streams, _sgi,				\
108 			     BW2VBPS(_bw,  351, 162,  78)) >> _s,	\
109 		MCS_DURATION(_streams, _sgi,				\
110 			     BW2VBPS(_bw,  468, 216, 104)) >> _s,	\
111 		MCS_DURATION(_streams, _sgi,				\
112 			     BW2VBPS(_bw,  702, 324, 156)) >> _s,	\
113 		MCS_DURATION(_streams, _sgi,				\
114 			     BW2VBPS(_bw,  936, 432, 208)) >> _s,	\
115 		MCS_DURATION(_streams, _sgi,				\
116 			     BW2VBPS(_bw, 1053, 486, 234)) >> _s,	\
117 		MCS_DURATION(_streams, _sgi,				\
118 			     BW2VBPS(_bw, 1170, 540, 260)) >> _s,	\
119 		MCS_DURATION(_streams, _sgi,				\
120 			     BW2VBPS(_bw, 1404, 648, 312)) >> _s,	\
121 		MCS_DURATION(_streams, _sgi,				\
122 			     BW2VBPS(_bw, 1560, 720, 346)) >> _s	\
123 	}								\
124 }
125 
126 #define VHT_GROUP_SHIFT(_streams, _sgi, _bw)				\
127 	GROUP_SHIFT(MCS_DURATION(_streams, _sgi,			\
128 				 BW2VBPS(_bw,  117,  54,  26)))
129 
130 #define VHT_GROUP(_streams, _sgi, _bw)					\
131 	__VHT_GROUP(_streams, _sgi, _bw,				\
132 		    VHT_GROUP_SHIFT(_streams, _sgi, _bw))
133 
134 #define CCK_DURATION(_bitrate, _short, _len)		\
135 	(1000 * (10 /* SIFS */ +			\
136 	 (_short ? 72 + 24 : 144 + 48) +		\
137 	 (8 * (_len + 4) * 10) / (_bitrate)))
138 
139 #define CCK_ACK_DURATION(_bitrate, _short)			\
140 	(CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) +	\
141 	 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
142 
143 #define CCK_DURATION_LIST(_short, _s)			\
144 	CCK_ACK_DURATION(10, _short) >> _s,		\
145 	CCK_ACK_DURATION(20, _short) >> _s,		\
146 	CCK_ACK_DURATION(55, _short) >> _s,		\
147 	CCK_ACK_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_ACK_DURATION(10, false))
162 
163 #define CCK_GROUP __CCK_GROUP(CCK_GROUP_SHIFT)
164 
165 
166 static bool minstrel_vht_only = true;
167 module_param(minstrel_vht_only, bool, 0644);
168 MODULE_PARM_DESC(minstrel_vht_only,
169 		 "Use only VHT rates when VHT is supported by sta.");
170 
171 /*
172  * To enable sufficiently targeted rate sampling, MCS rates are divided into
173  * groups, based on the number of streams and flags (HT40, SGI) that they
174  * use.
175  *
176  * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
177  * BW -> SGI -> #streams
178  */
179 const struct mcs_group minstrel_mcs_groups[] = {
180 	MCS_GROUP(1, 0, BW_20),
181 	MCS_GROUP(2, 0, BW_20),
182 	MCS_GROUP(3, 0, BW_20),
183 	MCS_GROUP(4, 0, BW_20),
184 
185 	MCS_GROUP(1, 1, BW_20),
186 	MCS_GROUP(2, 1, BW_20),
187 	MCS_GROUP(3, 1, BW_20),
188 	MCS_GROUP(4, 1, BW_20),
189 
190 	MCS_GROUP(1, 0, BW_40),
191 	MCS_GROUP(2, 0, BW_40),
192 	MCS_GROUP(3, 0, BW_40),
193 	MCS_GROUP(4, 0, BW_40),
194 
195 	MCS_GROUP(1, 1, BW_40),
196 	MCS_GROUP(2, 1, BW_40),
197 	MCS_GROUP(3, 1, BW_40),
198 	MCS_GROUP(4, 1, BW_40),
199 
200 	CCK_GROUP,
201 
202 	VHT_GROUP(1, 0, BW_20),
203 	VHT_GROUP(2, 0, BW_20),
204 	VHT_GROUP(3, 0, BW_20),
205 	VHT_GROUP(4, 0, BW_20),
206 
207 	VHT_GROUP(1, 1, BW_20),
208 	VHT_GROUP(2, 1, BW_20),
209 	VHT_GROUP(3, 1, BW_20),
210 	VHT_GROUP(4, 1, BW_20),
211 
212 	VHT_GROUP(1, 0, BW_40),
213 	VHT_GROUP(2, 0, BW_40),
214 	VHT_GROUP(3, 0, BW_40),
215 	VHT_GROUP(4, 0, BW_40),
216 
217 	VHT_GROUP(1, 1, BW_40),
218 	VHT_GROUP(2, 1, BW_40),
219 	VHT_GROUP(3, 1, BW_40),
220 	VHT_GROUP(4, 1, BW_40),
221 
222 	VHT_GROUP(1, 0, BW_80),
223 	VHT_GROUP(2, 0, BW_80),
224 	VHT_GROUP(3, 0, BW_80),
225 	VHT_GROUP(4, 0, BW_80),
226 
227 	VHT_GROUP(1, 1, BW_80),
228 	VHT_GROUP(2, 1, BW_80),
229 	VHT_GROUP(3, 1, BW_80),
230 	VHT_GROUP(4, 1, BW_80),
231 };
232 
233 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
234 
235 static void
236 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
237 
238 /*
239  * Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
240  * e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
241  *
242  * Returns the valid mcs map for struct minstrel_mcs_group_data.supported
243  */
244 static u16
245 minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
246 {
247 	u16 mask = 0;
248 
249 	if (bw == BW_20) {
250 		if (nss != 3 && nss != 6)
251 			mask = BIT(9);
252 	} else if (bw == BW_80) {
253 		if (nss == 3 || nss == 7)
254 			mask = BIT(6);
255 		else if (nss == 6)
256 			mask = BIT(9);
257 	} else {
258 		WARN_ON(bw != BW_40);
259 	}
260 
261 	switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
262 	case IEEE80211_VHT_MCS_SUPPORT_0_7:
263 		mask |= 0x300;
264 		break;
265 	case IEEE80211_VHT_MCS_SUPPORT_0_8:
266 		mask |= 0x200;
267 		break;
268 	case IEEE80211_VHT_MCS_SUPPORT_0_9:
269 		break;
270 	default:
271 		mask = 0x3ff;
272 	}
273 
274 	return 0x3ff & ~mask;
275 }
276 
277 /*
278  * Look up an MCS group index based on mac80211 rate information
279  */
280 static int
281 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
282 {
283 	return GROUP_IDX((rate->idx / 8) + 1,
284 			 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
285 			 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
286 }
287 
288 static int
289 minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
290 {
291 	return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
292 			     !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
293 			     !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
294 			     2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
295 }
296 
297 static struct minstrel_rate_stats *
298 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
299 		      struct ieee80211_tx_rate *rate)
300 {
301 	int group, idx;
302 
303 	if (rate->flags & IEEE80211_TX_RC_MCS) {
304 		group = minstrel_ht_get_group_idx(rate);
305 		idx = rate->idx % 8;
306 	} else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
307 		group = minstrel_vht_get_group_idx(rate);
308 		idx = ieee80211_rate_get_vht_mcs(rate);
309 	} else {
310 		group = MINSTREL_CCK_GROUP;
311 
312 		for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
313 			if (rate->idx == mp->cck_rates[idx])
314 				break;
315 
316 		/* short preamble */
317 		if ((mi->supported[group] & BIT(idx + 4)) &&
318 		    (rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE))
319 			idx += 4;
320 	}
321 	return &mi->groups[group].rates[idx];
322 }
323 
324 static inline struct minstrel_rate_stats *
325 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
326 {
327 	return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
328 }
329 
330 static unsigned int
331 minstrel_ht_avg_ampdu_len(struct minstrel_ht_sta *mi)
332 {
333 	if (!mi->avg_ampdu_len)
334 		return AVG_AMPDU_SIZE;
335 
336 	return MINSTREL_TRUNC(mi->avg_ampdu_len);
337 }
338 
339 /*
340  * Return current throughput based on the average A-MPDU length, taking into
341  * account the expected number of retransmissions and their expected length
342  */
343 int
344 minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate,
345 		       int prob_ewma)
346 {
347 	unsigned int nsecs = 0;
348 
349 	/* do not account throughput if sucess prob is below 10% */
350 	if (prob_ewma < MINSTREL_FRAC(10, 100))
351 		return 0;
352 
353 	if (group != MINSTREL_CCK_GROUP)
354 		nsecs = 1000 * mi->overhead / minstrel_ht_avg_ampdu_len(mi);
355 
356 	nsecs += minstrel_mcs_groups[group].duration[rate] <<
357 		 minstrel_mcs_groups[group].shift;
358 
359 	/*
360 	 * For the throughput calculation, limit the probability value to 90% to
361 	 * account for collision related packet error rate fluctuation
362 	 * (prob is scaled - see MINSTREL_FRAC above)
363 	 */
364 	if (prob_ewma > MINSTREL_FRAC(90, 100))
365 		return MINSTREL_TRUNC(100000 * ((MINSTREL_FRAC(90, 100) * 1000)
366 								      / nsecs));
367 	else
368 		return MINSTREL_TRUNC(100000 * ((prob_ewma * 1000) / nsecs));
369 }
370 
371 /*
372  * Find & sort topmost throughput rates
373  *
374  * If multiple rates provide equal throughput the sorting is based on their
375  * current success probability. Higher success probability is preferred among
376  * MCS groups, CCK rates do not provide aggregation and are therefore at last.
377  */
378 static void
379 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
380 			       u16 *tp_list)
381 {
382 	int cur_group, cur_idx, cur_tp_avg, cur_prob;
383 	int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
384 	int j = MAX_THR_RATES;
385 
386 	cur_group = index / MCS_GROUP_RATES;
387 	cur_idx = index  % MCS_GROUP_RATES;
388 	cur_prob = mi->groups[cur_group].rates[cur_idx].prob_ewma;
389 	cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob);
390 
391 	do {
392 		tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
393 		tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
394 		tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
395 		tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx,
396 						    tmp_prob);
397 		if (cur_tp_avg < tmp_tp_avg ||
398 		    (cur_tp_avg == tmp_tp_avg && cur_prob <= tmp_prob))
399 			break;
400 		j--;
401 	} while (j > 0);
402 
403 	if (j < MAX_THR_RATES - 1) {
404 		memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
405 		       (MAX_THR_RATES - (j + 1))));
406 	}
407 	if (j < MAX_THR_RATES)
408 		tp_list[j] = index;
409 }
410 
411 /*
412  * Find and set the topmost probability rate per sta and per group
413  */
414 static void
415 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
416 {
417 	struct minstrel_mcs_group_data *mg;
418 	struct minstrel_rate_stats *mrs;
419 	int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
420 	int max_tp_group, cur_tp_avg, cur_group, cur_idx;
421 	int max_gpr_group, max_gpr_idx;
422 	int max_gpr_tp_avg, max_gpr_prob;
423 
424 	cur_group = index / MCS_GROUP_RATES;
425 	cur_idx = index % MCS_GROUP_RATES;
426 	mg = &mi->groups[index / MCS_GROUP_RATES];
427 	mrs = &mg->rates[index % MCS_GROUP_RATES];
428 
429 	tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
430 	tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
431 	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
432 	tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
433 
434 	/* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
435 	 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
436 	max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
437 	if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
438 	    (max_tp_group != MINSTREL_CCK_GROUP))
439 		return;
440 
441 	max_gpr_group = mg->max_group_prob_rate / MCS_GROUP_RATES;
442 	max_gpr_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
443 	max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_ewma;
444 
445 	if (mrs->prob_ewma > MINSTREL_FRAC(75, 100)) {
446 		cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx,
447 						    mrs->prob_ewma);
448 		if (cur_tp_avg > tmp_tp_avg)
449 			mi->max_prob_rate = index;
450 
451 		max_gpr_tp_avg = minstrel_ht_get_tp_avg(mi, max_gpr_group,
452 							max_gpr_idx,
453 							max_gpr_prob);
454 		if (cur_tp_avg > max_gpr_tp_avg)
455 			mg->max_group_prob_rate = index;
456 	} else {
457 		if (mrs->prob_ewma > tmp_prob)
458 			mi->max_prob_rate = index;
459 		if (mrs->prob_ewma > max_gpr_prob)
460 			mg->max_group_prob_rate = index;
461 	}
462 }
463 
464 
465 /*
466  * Assign new rate set per sta and use CCK rates only if the fastest
467  * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
468  * rate sets where MCS and CCK rates are mixed, because CCK rates can
469  * not use aggregation.
470  */
471 static void
472 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
473 				 u16 tmp_mcs_tp_rate[MAX_THR_RATES],
474 				 u16 tmp_cck_tp_rate[MAX_THR_RATES])
475 {
476 	unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob;
477 	int i;
478 
479 	tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
480 	tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
481 	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
482 	tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
483 
484 	tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
485 	tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
486 	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
487 	tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
488 
489 	if (tmp_cck_tp > tmp_mcs_tp) {
490 		for(i = 0; i < MAX_THR_RATES; i++) {
491 			minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
492 						       tmp_mcs_tp_rate);
493 		}
494 	}
495 
496 }
497 
498 /*
499  * Try to increase robustness of max_prob rate by decrease number of
500  * streams if possible.
501  */
502 static inline void
503 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
504 {
505 	struct minstrel_mcs_group_data *mg;
506 	int tmp_max_streams, group, tmp_idx, tmp_prob;
507 	int tmp_tp = 0;
508 
509 	tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
510 			  MCS_GROUP_RATES].streams;
511 	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
512 		mg = &mi->groups[group];
513 		if (!mi->supported[group] || group == MINSTREL_CCK_GROUP)
514 			continue;
515 
516 		tmp_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
517 		tmp_prob = mi->groups[group].rates[tmp_idx].prob_ewma;
518 
519 		if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx, tmp_prob) &&
520 		   (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
521 				mi->max_prob_rate = mg->max_group_prob_rate;
522 				tmp_tp = minstrel_ht_get_tp_avg(mi, group,
523 								tmp_idx,
524 								tmp_prob);
525 		}
526 	}
527 }
528 
529 /*
530  * Update rate statistics and select new primary rates
531  *
532  * Rules for rate selection:
533  *  - max_prob_rate must use only one stream, as a tradeoff between delivery
534  *    probability and throughput during strong fluctuations
535  *  - as long as the max prob rate has a probability of more than 75%, pick
536  *    higher throughput rates, even if the probablity is a bit lower
537  */
538 static void
539 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
540 {
541 	struct minstrel_mcs_group_data *mg;
542 	struct minstrel_rate_stats *mrs;
543 	int group, i, j, cur_prob;
544 	u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
545 	u16 tmp_cck_tp_rate[MAX_THR_RATES], index;
546 
547 	if (mi->ampdu_packets > 0) {
548 		if (!ieee80211_hw_check(mp->hw, TX_STATUS_NO_AMPDU_LEN))
549 			mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
550 				MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets),
551 					      EWMA_LEVEL);
552 		else
553 			mi->avg_ampdu_len = 0;
554 		mi->ampdu_len = 0;
555 		mi->ampdu_packets = 0;
556 	}
557 
558 	mi->sample_slow = 0;
559 	mi->sample_count = 0;
560 
561 	/* Initialize global rate indexes */
562 	for(j = 0; j < MAX_THR_RATES; j++){
563 		tmp_mcs_tp_rate[j] = 0;
564 		tmp_cck_tp_rate[j] = 0;
565 	}
566 
567 	/* Find best rate sets within all MCS groups*/
568 	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
569 
570 		mg = &mi->groups[group];
571 		if (!mi->supported[group])
572 			continue;
573 
574 		mi->sample_count++;
575 
576 		/* (re)Initialize group rate indexes */
577 		for(j = 0; j < MAX_THR_RATES; j++)
578 			tmp_group_tp_rate[j] = group;
579 
580 		for (i = 0; i < MCS_GROUP_RATES; i++) {
581 			if (!(mi->supported[group] & BIT(i)))
582 				continue;
583 
584 			index = MCS_GROUP_RATES * group + i;
585 
586 			mrs = &mg->rates[i];
587 			mrs->retry_updated = false;
588 			minstrel_calc_rate_stats(mrs);
589 			cur_prob = mrs->prob_ewma;
590 
591 			if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
592 				continue;
593 
594 			/* Find max throughput rate set */
595 			if (group != MINSTREL_CCK_GROUP) {
596 				minstrel_ht_sort_best_tp_rates(mi, index,
597 							       tmp_mcs_tp_rate);
598 			} else if (group == MINSTREL_CCK_GROUP) {
599 				minstrel_ht_sort_best_tp_rates(mi, index,
600 							       tmp_cck_tp_rate);
601 			}
602 
603 			/* Find max throughput rate set within a group */
604 			minstrel_ht_sort_best_tp_rates(mi, index,
605 						       tmp_group_tp_rate);
606 
607 			/* Find max probability rate per group and global */
608 			minstrel_ht_set_best_prob_rate(mi, index);
609 		}
610 
611 		memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
612 		       sizeof(mg->max_group_tp_rate));
613 	}
614 
615 	/* Assign new rate set per sta */
616 	minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
617 	memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
618 
619 	/* Try to increase robustness of max_prob_rate*/
620 	minstrel_ht_prob_rate_reduce_streams(mi);
621 
622 	/* try to sample all available rates during each interval */
623 	mi->sample_count *= 8;
624 
625 #ifdef CONFIG_MAC80211_DEBUGFS
626 	/* use fixed index if set */
627 	if (mp->fixed_rate_idx != -1) {
628 		for (i = 0; i < 4; i++)
629 			mi->max_tp_rate[i] = mp->fixed_rate_idx;
630 		mi->max_prob_rate = mp->fixed_rate_idx;
631 	}
632 #endif
633 
634 	/* Reset update timer */
635 	mi->last_stats_update = jiffies;
636 }
637 
638 static bool
639 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
640 {
641 	if (rate->idx < 0)
642 		return false;
643 
644 	if (!rate->count)
645 		return false;
646 
647 	if (rate->flags & IEEE80211_TX_RC_MCS ||
648 	    rate->flags & IEEE80211_TX_RC_VHT_MCS)
649 		return true;
650 
651 	return rate->idx == mp->cck_rates[0] ||
652 	       rate->idx == mp->cck_rates[1] ||
653 	       rate->idx == mp->cck_rates[2] ||
654 	       rate->idx == mp->cck_rates[3];
655 }
656 
657 static void
658 minstrel_set_next_sample_idx(struct minstrel_ht_sta *mi)
659 {
660 	struct minstrel_mcs_group_data *mg;
661 
662 	for (;;) {
663 		mi->sample_group++;
664 		mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
665 		mg = &mi->groups[mi->sample_group];
666 
667 		if (!mi->supported[mi->sample_group])
668 			continue;
669 
670 		if (++mg->index >= MCS_GROUP_RATES) {
671 			mg->index = 0;
672 			if (++mg->column >= ARRAY_SIZE(sample_table))
673 				mg->column = 0;
674 		}
675 		break;
676 	}
677 }
678 
679 static void
680 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u16 *idx, bool primary)
681 {
682 	int group, orig_group;
683 
684 	orig_group = group = *idx / MCS_GROUP_RATES;
685 	while (group > 0) {
686 		group--;
687 
688 		if (!mi->supported[group])
689 			continue;
690 
691 		if (minstrel_mcs_groups[group].streams >
692 		    minstrel_mcs_groups[orig_group].streams)
693 			continue;
694 
695 		if (primary)
696 			*idx = mi->groups[group].max_group_tp_rate[0];
697 		else
698 			*idx = mi->groups[group].max_group_tp_rate[1];
699 		break;
700 	}
701 }
702 
703 static void
704 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
705 {
706 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
707 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
708 	u16 tid;
709 
710 	if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
711 		return;
712 
713 	if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
714 		return;
715 
716 	if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
717 		return;
718 
719 	tid = ieee80211_get_tid(hdr);
720 	if (likely(sta->ampdu_mlme.tid_tx[tid]))
721 		return;
722 
723 	ieee80211_start_tx_ba_session(pubsta, tid, 0);
724 }
725 
726 static void
727 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
728                       void *priv_sta, struct ieee80211_tx_status *st)
729 {
730 	struct ieee80211_tx_info *info = st->info;
731 	struct minstrel_ht_sta_priv *msp = priv_sta;
732 	struct minstrel_ht_sta *mi = &msp->ht;
733 	struct ieee80211_tx_rate *ar = info->status.rates;
734 	struct minstrel_rate_stats *rate, *rate2;
735 	struct minstrel_priv *mp = priv;
736 	bool last, update = false;
737 	int i;
738 
739 	if (!msp->is_ht)
740 		return mac80211_minstrel.tx_status_ext(priv, sband,
741 						       &msp->legacy, st);
742 
743 	/* This packet was aggregated but doesn't carry status info */
744 	if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
745 	    !(info->flags & IEEE80211_TX_STAT_AMPDU))
746 		return;
747 
748 	if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
749 		info->status.ampdu_ack_len =
750 			(info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
751 		info->status.ampdu_len = 1;
752 	}
753 
754 	mi->ampdu_packets++;
755 	mi->ampdu_len += info->status.ampdu_len;
756 
757 	if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
758 		int avg_ampdu_len = minstrel_ht_avg_ampdu_len(mi);
759 
760 		mi->sample_wait = 16 + 2 * avg_ampdu_len;
761 		mi->sample_tries = 1;
762 		mi->sample_count--;
763 	}
764 
765 	if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
766 		mi->sample_packets += info->status.ampdu_len;
767 
768 	last = !minstrel_ht_txstat_valid(mp, &ar[0]);
769 	for (i = 0; !last; i++) {
770 		last = (i == IEEE80211_TX_MAX_RATES - 1) ||
771 		       !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
772 
773 		rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
774 
775 		if (last)
776 			rate->success += info->status.ampdu_ack_len;
777 
778 		rate->attempts += ar[i].count * info->status.ampdu_len;
779 	}
780 
781 	/*
782 	 * check for sudden death of spatial multiplexing,
783 	 * downgrade to a lower number of streams if necessary.
784 	 */
785 	rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
786 	if (rate->attempts > 30 &&
787 	    MINSTREL_FRAC(rate->success, rate->attempts) <
788 	    MINSTREL_FRAC(20, 100)) {
789 		minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
790 		update = true;
791 	}
792 
793 	rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
794 	if (rate2->attempts > 30 &&
795 	    MINSTREL_FRAC(rate2->success, rate2->attempts) <
796 	    MINSTREL_FRAC(20, 100)) {
797 		minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
798 		update = true;
799 	}
800 
801 	if (time_after(jiffies, mi->last_stats_update +
802 				(mp->update_interval / 2 * HZ) / 1000)) {
803 		update = true;
804 		minstrel_ht_update_stats(mp, mi);
805 	}
806 
807 	if (update)
808 		minstrel_ht_update_rates(mp, mi);
809 }
810 
811 static inline int
812 minstrel_get_duration(int index)
813 {
814 	const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
815 	unsigned int duration = group->duration[index % MCS_GROUP_RATES];
816 	return duration << group->shift;
817 }
818 
819 static void
820 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
821                          int index)
822 {
823 	struct minstrel_rate_stats *mrs;
824 	unsigned int tx_time, tx_time_rtscts, tx_time_data;
825 	unsigned int cw = mp->cw_min;
826 	unsigned int ctime = 0;
827 	unsigned int t_slot = 9; /* FIXME */
828 	unsigned int ampdu_len = minstrel_ht_avg_ampdu_len(mi);
829 	unsigned int overhead = 0, overhead_rtscts = 0;
830 
831 	mrs = minstrel_get_ratestats(mi, index);
832 	if (mrs->prob_ewma < MINSTREL_FRAC(1, 10)) {
833 		mrs->retry_count = 1;
834 		mrs->retry_count_rtscts = 1;
835 		return;
836 	}
837 
838 	mrs->retry_count = 2;
839 	mrs->retry_count_rtscts = 2;
840 	mrs->retry_updated = true;
841 
842 	tx_time_data = minstrel_get_duration(index) * ampdu_len / 1000;
843 
844 	/* Contention time for first 2 tries */
845 	ctime = (t_slot * cw) >> 1;
846 	cw = min((cw << 1) | 1, mp->cw_max);
847 	ctime += (t_slot * cw) >> 1;
848 	cw = min((cw << 1) | 1, mp->cw_max);
849 
850 	if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
851 		overhead = mi->overhead;
852 		overhead_rtscts = mi->overhead_rtscts;
853 	}
854 
855 	/* Total TX time for data and Contention after first 2 tries */
856 	tx_time = ctime + 2 * (overhead + tx_time_data);
857 	tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
858 
859 	/* See how many more tries we can fit inside segment size */
860 	do {
861 		/* Contention time for this try */
862 		ctime = (t_slot * cw) >> 1;
863 		cw = min((cw << 1) | 1, mp->cw_max);
864 
865 		/* Total TX time after this try */
866 		tx_time += ctime + overhead + tx_time_data;
867 		tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
868 
869 		if (tx_time_rtscts < mp->segment_size)
870 			mrs->retry_count_rtscts++;
871 	} while ((tx_time < mp->segment_size) &&
872 	         (++mrs->retry_count < mp->max_retry));
873 }
874 
875 
876 static void
877 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
878                      struct ieee80211_sta_rates *ratetbl, int offset, int index)
879 {
880 	const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
881 	struct minstrel_rate_stats *mrs;
882 	u8 idx;
883 	u16 flags = group->flags;
884 
885 	mrs = minstrel_get_ratestats(mi, index);
886 	if (!mrs->retry_updated)
887 		minstrel_calc_retransmit(mp, mi, index);
888 
889 	if (mrs->prob_ewma < MINSTREL_FRAC(20, 100) || !mrs->retry_count) {
890 		ratetbl->rate[offset].count = 2;
891 		ratetbl->rate[offset].count_rts = 2;
892 		ratetbl->rate[offset].count_cts = 2;
893 	} else {
894 		ratetbl->rate[offset].count = mrs->retry_count;
895 		ratetbl->rate[offset].count_cts = mrs->retry_count;
896 		ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
897 	}
898 
899 	if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
900 		idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
901 	else if (flags & IEEE80211_TX_RC_VHT_MCS)
902 		idx = ((group->streams - 1) << 4) |
903 		      ((index % MCS_GROUP_RATES) & 0xF);
904 	else
905 		idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
906 
907 	/* enable RTS/CTS if needed:
908 	 *  - if station is in dynamic SMPS (and streams > 1)
909 	 *  - for fallback rates, to increase chances of getting through
910 	 */
911 	if (offset > 0 ||
912 	    (mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
913 	     group->streams > 1)) {
914 		ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
915 		flags |= IEEE80211_TX_RC_USE_RTS_CTS;
916 	}
917 
918 	ratetbl->rate[offset].idx = idx;
919 	ratetbl->rate[offset].flags = flags;
920 }
921 
922 static inline int
923 minstrel_ht_get_prob_ewma(struct minstrel_ht_sta *mi, int rate)
924 {
925 	int group = rate / MCS_GROUP_RATES;
926 	rate %= MCS_GROUP_RATES;
927 	return mi->groups[group].rates[rate].prob_ewma;
928 }
929 
930 static int
931 minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
932 {
933 	int group = mi->max_prob_rate / MCS_GROUP_RATES;
934 	const struct mcs_group *g = &minstrel_mcs_groups[group];
935 	int rate = mi->max_prob_rate % MCS_GROUP_RATES;
936 	unsigned int duration;
937 
938 	/* Disable A-MSDU if max_prob_rate is bad */
939 	if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100))
940 		return 1;
941 
942 	duration = g->duration[rate];
943 	duration <<= g->shift;
944 
945 	/* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
946 	if (duration > MCS_DURATION(1, 0, 52))
947 		return 500;
948 
949 	/*
950 	 * If the rate is slower than single-stream MCS4, limit A-MSDU to usual
951 	 * data packet size
952 	 */
953 	if (duration > MCS_DURATION(1, 0, 104))
954 		return 1600;
955 
956 	/*
957 	 * If the rate is slower than single-stream MCS7, or if the max throughput
958 	 * rate success probability is less than 75%, limit A-MSDU to twice the usual
959 	 * data packet size
960 	 */
961 	if (duration > MCS_DURATION(1, 0, 260) ||
962 	    (minstrel_ht_get_prob_ewma(mi, mi->max_tp_rate[0]) <
963 	     MINSTREL_FRAC(75, 100)))
964 		return 3200;
965 
966 	/*
967 	 * HT A-MPDU limits maximum MPDU size under BA agreement to 4095 bytes.
968 	 * Since aggregation sessions are started/stopped without txq flush, use
969 	 * the limit here to avoid the complexity of having to de-aggregate
970 	 * packets in the queue.
971 	 */
972 	if (!mi->sta->vht_cap.vht_supported)
973 		return IEEE80211_MAX_MPDU_LEN_HT_BA;
974 
975 	/* unlimited */
976 	return 0;
977 }
978 
979 static void
980 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
981 {
982 	struct ieee80211_sta_rates *rates;
983 	int i = 0;
984 
985 	rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
986 	if (!rates)
987 		return;
988 
989 	/* Start with max_tp_rate[0] */
990 	minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
991 
992 	if (mp->hw->max_rates >= 3) {
993 		/* At least 3 tx rates supported, use max_tp_rate[1] next */
994 		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
995 	}
996 
997 	if (mp->hw->max_rates >= 2) {
998 		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
999 	}
1000 
1001 	mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi);
1002 	rates->rate[i].idx = -1;
1003 	rate_control_set_rates(mp->hw, mi->sta, rates);
1004 }
1005 
1006 static int
1007 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
1008 {
1009 	struct minstrel_rate_stats *mrs;
1010 	struct minstrel_mcs_group_data *mg;
1011 	unsigned int sample_dur, sample_group, cur_max_tp_streams;
1012 	int tp_rate1, tp_rate2;
1013 	int sample_idx = 0;
1014 
1015 	if (mi->sample_wait > 0) {
1016 		mi->sample_wait--;
1017 		return -1;
1018 	}
1019 
1020 	if (!mi->sample_tries)
1021 		return -1;
1022 
1023 	sample_group = mi->sample_group;
1024 	mg = &mi->groups[sample_group];
1025 	sample_idx = sample_table[mg->column][mg->index];
1026 	minstrel_set_next_sample_idx(mi);
1027 
1028 	if (!(mi->supported[sample_group] & BIT(sample_idx)))
1029 		return -1;
1030 
1031 	mrs = &mg->rates[sample_idx];
1032 	sample_idx += sample_group * MCS_GROUP_RATES;
1033 
1034 	/* Set tp_rate1, tp_rate2 to the highest / second highest max_tp_rate */
1035 	if (minstrel_get_duration(mi->max_tp_rate[0]) >
1036 	    minstrel_get_duration(mi->max_tp_rate[1])) {
1037 		tp_rate1 = mi->max_tp_rate[1];
1038 		tp_rate2 = mi->max_tp_rate[0];
1039 	} else {
1040 		tp_rate1 = mi->max_tp_rate[0];
1041 		tp_rate2 = mi->max_tp_rate[1];
1042 	}
1043 
1044 	/*
1045 	 * Sampling might add some overhead (RTS, no aggregation)
1046 	 * to the frame. Hence, don't use sampling for the highest currently
1047 	 * used highest throughput or probability rate.
1048 	 */
1049 	if (sample_idx == mi->max_tp_rate[0] || sample_idx == mi->max_prob_rate)
1050 		return -1;
1051 
1052 	/*
1053 	 * Do not sample if the probability is already higher than 95%,
1054 	 * or if the rate is 3 times slower than the current max probability
1055 	 * rate, to avoid wasting airtime.
1056 	 */
1057 	sample_dur = minstrel_get_duration(sample_idx);
1058 	if (mrs->prob_ewma > MINSTREL_FRAC(95, 100) ||
1059 	    minstrel_get_duration(mi->max_prob_rate) * 3 < sample_dur)
1060 		return -1;
1061 
1062 	/*
1063 	 * Make sure that lower rates get sampled only occasionally,
1064 	 * if the link is working perfectly.
1065 	 */
1066 
1067 	cur_max_tp_streams = minstrel_mcs_groups[tp_rate1 /
1068 		MCS_GROUP_RATES].streams;
1069 	if (sample_dur >= minstrel_get_duration(tp_rate2) &&
1070 	    (cur_max_tp_streams - 1 <
1071 	     minstrel_mcs_groups[sample_group].streams ||
1072 	     sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
1073 		if (mrs->sample_skipped < 20)
1074 			return -1;
1075 
1076 		if (mi->sample_slow++ > 2)
1077 			return -1;
1078 	}
1079 	mi->sample_tries--;
1080 
1081 	return sample_idx;
1082 }
1083 
1084 static void
1085 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
1086                      struct ieee80211_tx_rate_control *txrc)
1087 {
1088 	const struct mcs_group *sample_group;
1089 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
1090 	struct ieee80211_tx_rate *rate = &info->status.rates[0];
1091 	struct minstrel_ht_sta_priv *msp = priv_sta;
1092 	struct minstrel_ht_sta *mi = &msp->ht;
1093 	struct minstrel_priv *mp = priv;
1094 	int sample_idx;
1095 
1096 	if (rate_control_send_low(sta, priv_sta, txrc))
1097 		return;
1098 
1099 	if (!msp->is_ht)
1100 		return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
1101 
1102 	if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
1103 	    mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
1104 		minstrel_aggr_check(sta, txrc->skb);
1105 
1106 	info->flags |= mi->tx_flags;
1107 
1108 #ifdef CONFIG_MAC80211_DEBUGFS
1109 	if (mp->fixed_rate_idx != -1)
1110 		return;
1111 #endif
1112 
1113 	/* Don't use EAPOL frames for sampling on non-mrr hw */
1114 	if (mp->hw->max_rates == 1 &&
1115 	    (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
1116 		sample_idx = -1;
1117 	else
1118 		sample_idx = minstrel_get_sample_rate(mp, mi);
1119 
1120 	mi->total_packets++;
1121 
1122 	/* wraparound */
1123 	if (mi->total_packets == ~0) {
1124 		mi->total_packets = 0;
1125 		mi->sample_packets = 0;
1126 	}
1127 
1128 	if (sample_idx < 0)
1129 		return;
1130 
1131 	sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
1132 	sample_idx %= MCS_GROUP_RATES;
1133 
1134 	if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP] &&
1135 	    (sample_idx >= 4) != txrc->short_preamble)
1136 		return;
1137 
1138 	info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
1139 	rate->count = 1;
1140 
1141 	if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP]) {
1142 		int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
1143 		rate->idx = mp->cck_rates[idx];
1144 	} else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
1145 		ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
1146 				       sample_group->streams);
1147 	} else {
1148 		rate->idx = sample_idx + (sample_group->streams - 1) * 8;
1149 	}
1150 
1151 	rate->flags = sample_group->flags;
1152 }
1153 
1154 static void
1155 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1156 		       struct ieee80211_supported_band *sband,
1157 		       struct ieee80211_sta *sta)
1158 {
1159 	int i;
1160 
1161 	if (sband->band != NL80211_BAND_2GHZ)
1162 		return;
1163 
1164 	if (!ieee80211_hw_check(mp->hw, SUPPORTS_HT_CCK_RATES))
1165 		return;
1166 
1167 	mi->cck_supported = 0;
1168 	mi->cck_supported_short = 0;
1169 	for (i = 0; i < 4; i++) {
1170 		if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
1171 			continue;
1172 
1173 		mi->cck_supported |= BIT(i);
1174 		if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
1175 			mi->cck_supported_short |= BIT(i);
1176 	}
1177 
1178 	mi->supported[MINSTREL_CCK_GROUP] = mi->cck_supported;
1179 }
1180 
1181 static void
1182 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
1183 			struct cfg80211_chan_def *chandef,
1184                         struct ieee80211_sta *sta, void *priv_sta)
1185 {
1186 	struct minstrel_priv *mp = priv;
1187 	struct minstrel_ht_sta_priv *msp = priv_sta;
1188 	struct minstrel_ht_sta *mi = &msp->ht;
1189 	struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
1190 	u16 ht_cap = sta->ht_cap.cap;
1191 	struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
1192 	int use_vht;
1193 	int n_supported = 0;
1194 	int ack_dur;
1195 	int stbc;
1196 	int i;
1197 	bool ldpc;
1198 
1199 	/* fall back to the old minstrel for legacy stations */
1200 	if (!sta->ht_cap.ht_supported)
1201 		goto use_legacy;
1202 
1203 	BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);
1204 
1205 	if (vht_cap->vht_supported)
1206 		use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
1207 	else
1208 		use_vht = 0;
1209 
1210 	msp->is_ht = true;
1211 	memset(mi, 0, sizeof(*mi));
1212 
1213 	mi->sta = sta;
1214 	mi->last_stats_update = jiffies;
1215 
1216 	ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
1217 	mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
1218 	mi->overhead += ack_dur;
1219 	mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
1220 
1221 	mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
1222 
1223 	/* When using MRR, sample more on the first attempt, without delay */
1224 	if (mp->has_mrr) {
1225 		mi->sample_count = 16;
1226 		mi->sample_wait = 0;
1227 	} else {
1228 		mi->sample_count = 8;
1229 		mi->sample_wait = 8;
1230 	}
1231 	mi->sample_tries = 4;
1232 
1233 	if (!use_vht) {
1234 		stbc = (ht_cap & IEEE80211_HT_CAP_RX_STBC) >>
1235 			IEEE80211_HT_CAP_RX_STBC_SHIFT;
1236 
1237 		ldpc = ht_cap & IEEE80211_HT_CAP_LDPC_CODING;
1238 	} else {
1239 		stbc = (vht_cap->cap & IEEE80211_VHT_CAP_RXSTBC_MASK) >>
1240 			IEEE80211_VHT_CAP_RXSTBC_SHIFT;
1241 
1242 		ldpc = vht_cap->cap & IEEE80211_VHT_CAP_RXLDPC;
1243 	}
1244 
1245 	mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
1246 	if (ldpc)
1247 		mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
1248 
1249 	for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
1250 		u32 gflags = minstrel_mcs_groups[i].flags;
1251 		int bw, nss;
1252 
1253 		mi->supported[i] = 0;
1254 		if (i == MINSTREL_CCK_GROUP) {
1255 			minstrel_ht_update_cck(mp, mi, sband, sta);
1256 			continue;
1257 		}
1258 
1259 		if (gflags & IEEE80211_TX_RC_SHORT_GI) {
1260 			if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
1261 				if (!(ht_cap & IEEE80211_HT_CAP_SGI_40))
1262 					continue;
1263 			} else {
1264 				if (!(ht_cap & IEEE80211_HT_CAP_SGI_20))
1265 					continue;
1266 			}
1267 		}
1268 
1269 		if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
1270 		    sta->bandwidth < IEEE80211_STA_RX_BW_40)
1271 			continue;
1272 
1273 		nss = minstrel_mcs_groups[i].streams;
1274 
1275 		/* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1276 		if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1)
1277 			continue;
1278 
1279 		/* HT rate */
1280 		if (gflags & IEEE80211_TX_RC_MCS) {
1281 			if (use_vht && minstrel_vht_only)
1282 				continue;
1283 
1284 			mi->supported[i] = mcs->rx_mask[nss - 1];
1285 			if (mi->supported[i])
1286 				n_supported++;
1287 			continue;
1288 		}
1289 
1290 		/* VHT rate */
1291 		if (!vht_cap->vht_supported ||
1292 		    WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) ||
1293 		    WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH))
1294 			continue;
1295 
1296 		if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) {
1297 			if (sta->bandwidth < IEEE80211_STA_RX_BW_80 ||
1298 			    ((gflags & IEEE80211_TX_RC_SHORT_GI) &&
1299 			     !(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) {
1300 				continue;
1301 			}
1302 		}
1303 
1304 		if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
1305 			bw = BW_40;
1306 		else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
1307 			bw = BW_80;
1308 		else
1309 			bw = BW_20;
1310 
1311 		mi->supported[i] = minstrel_get_valid_vht_rates(bw, nss,
1312 				vht_cap->vht_mcs.tx_mcs_map);
1313 
1314 		if (mi->supported[i])
1315 			n_supported++;
1316 	}
1317 
1318 	if (!n_supported)
1319 		goto use_legacy;
1320 
1321 	mi->supported[MINSTREL_CCK_GROUP] |= mi->cck_supported_short << 4;
1322 
1323 	/* create an initial rate table with the lowest supported rates */
1324 	minstrel_ht_update_stats(mp, mi);
1325 	minstrel_ht_update_rates(mp, mi);
1326 
1327 	return;
1328 
1329 use_legacy:
1330 	msp->is_ht = false;
1331 	memset(&msp->legacy, 0, sizeof(msp->legacy));
1332 	msp->legacy.r = msp->ratelist;
1333 	msp->legacy.sample_table = msp->sample_table;
1334 	return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
1335 					   &msp->legacy);
1336 }
1337 
1338 static void
1339 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
1340 		      struct cfg80211_chan_def *chandef,
1341                       struct ieee80211_sta *sta, void *priv_sta)
1342 {
1343 	minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1344 }
1345 
1346 static void
1347 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
1348 			struct cfg80211_chan_def *chandef,
1349                         struct ieee80211_sta *sta, void *priv_sta,
1350                         u32 changed)
1351 {
1352 	minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1353 }
1354 
1355 static void *
1356 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
1357 {
1358 	struct ieee80211_supported_band *sband;
1359 	struct minstrel_ht_sta_priv *msp;
1360 	struct minstrel_priv *mp = priv;
1361 	struct ieee80211_hw *hw = mp->hw;
1362 	int max_rates = 0;
1363 	int i;
1364 
1365 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1366 		sband = hw->wiphy->bands[i];
1367 		if (sband && sband->n_bitrates > max_rates)
1368 			max_rates = sband->n_bitrates;
1369 	}
1370 
1371 	msp = kzalloc(sizeof(*msp), gfp);
1372 	if (!msp)
1373 		return NULL;
1374 
1375 	msp->ratelist = kcalloc(max_rates, sizeof(struct minstrel_rate), gfp);
1376 	if (!msp->ratelist)
1377 		goto error;
1378 
1379 	msp->sample_table = kmalloc_array(max_rates, SAMPLE_COLUMNS, gfp);
1380 	if (!msp->sample_table)
1381 		goto error1;
1382 
1383 	return msp;
1384 
1385 error1:
1386 	kfree(msp->ratelist);
1387 error:
1388 	kfree(msp);
1389 	return NULL;
1390 }
1391 
1392 static void
1393 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1394 {
1395 	struct minstrel_ht_sta_priv *msp = priv_sta;
1396 
1397 	kfree(msp->sample_table);
1398 	kfree(msp->ratelist);
1399 	kfree(msp);
1400 }
1401 
1402 static void
1403 minstrel_ht_init_cck_rates(struct minstrel_priv *mp)
1404 {
1405 	static const int bitrates[4] = { 10, 20, 55, 110 };
1406 	struct ieee80211_supported_band *sband;
1407 	u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
1408 	int i, j;
1409 
1410 	sband = mp->hw->wiphy->bands[NL80211_BAND_2GHZ];
1411 	if (!sband)
1412 		return;
1413 
1414 	for (i = 0; i < sband->n_bitrates; i++) {
1415 		struct ieee80211_rate *rate = &sband->bitrates[i];
1416 
1417 		if (rate->flags & IEEE80211_RATE_ERP_G)
1418 			continue;
1419 
1420 		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
1421 			continue;
1422 
1423 		for (j = 0; j < ARRAY_SIZE(bitrates); j++) {
1424 			if (rate->bitrate != bitrates[j])
1425 				continue;
1426 
1427 			mp->cck_rates[j] = i;
1428 			break;
1429 		}
1430 	}
1431 }
1432 
1433 static void *
1434 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1435 {
1436 	struct minstrel_priv *mp;
1437 
1438 	mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
1439 	if (!mp)
1440 		return NULL;
1441 
1442 	/* contention window settings
1443 	 * Just an approximation. Using the per-queue values would complicate
1444 	 * the calculations and is probably unnecessary */
1445 	mp->cw_min = 15;
1446 	mp->cw_max = 1023;
1447 
1448 	/* number of packets (in %) to use for sampling other rates
1449 	 * sample less often for non-mrr packets, because the overhead
1450 	 * is much higher than with mrr */
1451 	mp->lookaround_rate = 5;
1452 	mp->lookaround_rate_mrr = 10;
1453 
1454 	/* maximum time that the hw is allowed to stay in one MRR segment */
1455 	mp->segment_size = 6000;
1456 
1457 	if (hw->max_rate_tries > 0)
1458 		mp->max_retry = hw->max_rate_tries;
1459 	else
1460 		/* safe default, does not necessarily have to match hw properties */
1461 		mp->max_retry = 7;
1462 
1463 	if (hw->max_rates >= 4)
1464 		mp->has_mrr = true;
1465 
1466 	mp->hw = hw;
1467 	mp->update_interval = 100;
1468 
1469 #ifdef CONFIG_MAC80211_DEBUGFS
1470 	mp->fixed_rate_idx = (u32) -1;
1471 	debugfs_create_u32("fixed_rate_idx", S_IRUGO | S_IWUGO, debugfsdir,
1472 			   &mp->fixed_rate_idx);
1473 #endif
1474 
1475 	minstrel_ht_init_cck_rates(mp);
1476 
1477 	return mp;
1478 }
1479 
1480 static void
1481 minstrel_ht_free(void *priv)
1482 {
1483 	kfree(priv);
1484 }
1485 
1486 static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1487 {
1488 	struct minstrel_ht_sta_priv *msp = priv_sta;
1489 	struct minstrel_ht_sta *mi = &msp->ht;
1490 	int i, j, prob, tp_avg;
1491 
1492 	if (!msp->is_ht)
1493 		return mac80211_minstrel.get_expected_throughput(priv_sta);
1494 
1495 	i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
1496 	j = mi->max_tp_rate[0] % MCS_GROUP_RATES;
1497 	prob = mi->groups[i].rates[j].prob_ewma;
1498 
1499 	/* convert tp_avg from pkt per second in kbps */
1500 	tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * 10;
1501 	tp_avg = tp_avg * AVG_PKT_SIZE * 8 / 1024;
1502 
1503 	return tp_avg;
1504 }
1505 
1506 static const struct rate_control_ops mac80211_minstrel_ht = {
1507 	.name = "minstrel_ht",
1508 	.tx_status_ext = minstrel_ht_tx_status,
1509 	.get_rate = minstrel_ht_get_rate,
1510 	.rate_init = minstrel_ht_rate_init,
1511 	.rate_update = minstrel_ht_rate_update,
1512 	.alloc_sta = minstrel_ht_alloc_sta,
1513 	.free_sta = minstrel_ht_free_sta,
1514 	.alloc = minstrel_ht_alloc,
1515 	.free = minstrel_ht_free,
1516 #ifdef CONFIG_MAC80211_DEBUGFS
1517 	.add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1518 #endif
1519 	.get_expected_throughput = minstrel_ht_get_expected_throughput,
1520 };
1521 
1522 
1523 static void __init init_sample_table(void)
1524 {
1525 	int col, i, new_idx;
1526 	u8 rnd[MCS_GROUP_RATES];
1527 
1528 	memset(sample_table, 0xff, sizeof(sample_table));
1529 	for (col = 0; col < SAMPLE_COLUMNS; col++) {
1530 		prandom_bytes(rnd, sizeof(rnd));
1531 		for (i = 0; i < MCS_GROUP_RATES; i++) {
1532 			new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1533 			while (sample_table[col][new_idx] != 0xff)
1534 				new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1535 
1536 			sample_table[col][new_idx] = i;
1537 		}
1538 	}
1539 }
1540 
1541 int __init
1542 rc80211_minstrel_init(void)
1543 {
1544 	init_sample_table();
1545 	return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1546 }
1547 
1548 void
1549 rc80211_minstrel_exit(void)
1550 {
1551 	ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1552 }
1553