1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
4  * Copyright (C) 2019-2021 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 /* 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 	.bw = _ht40,							\
62 	.flags =							\
63 		IEEE80211_TX_RC_MCS |					\
64 		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
65 		(_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),		\
66 	.duration = {							\
67 		MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26) >> _s,	\
68 		MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52) >> _s,	\
69 		MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78) >> _s,	\
70 		MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104) >> _s,	\
71 		MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156) >> _s,	\
72 		MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208) >> _s,	\
73 		MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234) >> _s,	\
74 		MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) >> _s	\
75 	}								\
76 }
77 
78 #define MCS_GROUP_SHIFT(_streams, _sgi, _ht40)				\
79 	GROUP_SHIFT(MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26))
80 
81 #define MCS_GROUP(_streams, _sgi, _ht40)				\
82 	__MCS_GROUP(_streams, _sgi, _ht40,				\
83 		    MCS_GROUP_SHIFT(_streams, _sgi, _ht40))
84 
85 #define VHT_GROUP_IDX(_streams, _sgi, _bw)				\
86 	(MINSTREL_VHT_GROUP_0 +						\
87 	 MINSTREL_MAX_STREAMS * 2 * (_bw) +				\
88 	 MINSTREL_MAX_STREAMS * (_sgi) +				\
89 	 (_streams) - 1)
90 
91 #define BW2VBPS(_bw, r3, r2, r1)					\
92 	(_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
93 
94 #define __VHT_GROUP(_streams, _sgi, _bw, _s)				\
95 	[VHT_GROUP_IDX(_streams, _sgi, _bw)] = {			\
96 	.streams = _streams,						\
97 	.shift = _s,							\
98 	.bw = _bw,							\
99 	.flags =							\
100 		IEEE80211_TX_RC_VHT_MCS |				\
101 		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
102 		(_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH :		\
103 		 _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),	\
104 	.duration = {							\
105 		MCS_DURATION(_streams, _sgi,				\
106 			     BW2VBPS(_bw,  117,  54,  26)) >> _s,	\
107 		MCS_DURATION(_streams, _sgi,				\
108 			     BW2VBPS(_bw,  234, 108,  52)) >> _s,	\
109 		MCS_DURATION(_streams, _sgi,				\
110 			     BW2VBPS(_bw,  351, 162,  78)) >> _s,	\
111 		MCS_DURATION(_streams, _sgi,				\
112 			     BW2VBPS(_bw,  468, 216, 104)) >> _s,	\
113 		MCS_DURATION(_streams, _sgi,				\
114 			     BW2VBPS(_bw,  702, 324, 156)) >> _s,	\
115 		MCS_DURATION(_streams, _sgi,				\
116 			     BW2VBPS(_bw,  936, 432, 208)) >> _s,	\
117 		MCS_DURATION(_streams, _sgi,				\
118 			     BW2VBPS(_bw, 1053, 486, 234)) >> _s,	\
119 		MCS_DURATION(_streams, _sgi,				\
120 			     BW2VBPS(_bw, 1170, 540, 260)) >> _s,	\
121 		MCS_DURATION(_streams, _sgi,				\
122 			     BW2VBPS(_bw, 1404, 648, 312)) >> _s,	\
123 		MCS_DURATION(_streams, _sgi,				\
124 			     BW2VBPS(_bw, 1560, 720, 346)) >> _s	\
125 	}								\
126 }
127 
128 #define VHT_GROUP_SHIFT(_streams, _sgi, _bw)				\
129 	GROUP_SHIFT(MCS_DURATION(_streams, _sgi,			\
130 				 BW2VBPS(_bw,  117,  54,  26)))
131 
132 #define VHT_GROUP(_streams, _sgi, _bw)					\
133 	__VHT_GROUP(_streams, _sgi, _bw,				\
134 		    VHT_GROUP_SHIFT(_streams, _sgi, _bw))
135 
136 #define CCK_DURATION(_bitrate, _short)			\
137 	(1000 * (10 /* SIFS */ +			\
138 	 (_short ? 72 + 24 : 144 + 48) +		\
139 	 (8 * (AVG_PKT_SIZE + 4) * 10) / (_bitrate)))
140 
141 #define CCK_DURATION_LIST(_short, _s)			\
142 	CCK_DURATION(10, _short) >> _s,			\
143 	CCK_DURATION(20, _short) >> _s,			\
144 	CCK_DURATION(55, _short) >> _s,			\
145 	CCK_DURATION(110, _short) >> _s
146 
147 #define __CCK_GROUP(_s)					\
148 	[MINSTREL_CCK_GROUP] = {			\
149 		.streams = 1,				\
150 		.flags = 0,				\
151 		.shift = _s,				\
152 		.duration = {				\
153 			CCK_DURATION_LIST(false, _s),	\
154 			CCK_DURATION_LIST(true, _s)	\
155 		}					\
156 	}
157 
158 #define CCK_GROUP_SHIFT					\
159 	GROUP_SHIFT(CCK_DURATION(10, false))
160 
161 #define CCK_GROUP __CCK_GROUP(CCK_GROUP_SHIFT)
162 
163 #define OFDM_DURATION(_bitrate)				\
164 	(1000 * (16 /* SIFS + signal ext */ +		\
165 	 16 /* T_PREAMBLE */ +				\
166 	 4 /* T_SIGNAL */ +				\
167 	 4 * (((16 + 80 * (AVG_PKT_SIZE + 4) + 6) /	\
168 	      ((_bitrate) * 4)))))
169 
170 #define OFDM_DURATION_LIST(_s)				\
171 	OFDM_DURATION(60) >> _s,			\
172 	OFDM_DURATION(90) >> _s,			\
173 	OFDM_DURATION(120) >> _s,			\
174 	OFDM_DURATION(180) >> _s,			\
175 	OFDM_DURATION(240) >> _s,			\
176 	OFDM_DURATION(360) >> _s,			\
177 	OFDM_DURATION(480) >> _s,			\
178 	OFDM_DURATION(540) >> _s
179 
180 #define __OFDM_GROUP(_s)				\
181 	[MINSTREL_OFDM_GROUP] = {			\
182 		.streams = 1,				\
183 		.flags = 0,				\
184 		.shift = _s,				\
185 		.duration = {				\
186 			OFDM_DURATION_LIST(_s),		\
187 		}					\
188 	}
189 
190 #define OFDM_GROUP_SHIFT				\
191 	GROUP_SHIFT(OFDM_DURATION(60))
192 
193 #define OFDM_GROUP __OFDM_GROUP(OFDM_GROUP_SHIFT)
194 
195 
196 static bool minstrel_vht_only = true;
197 module_param(minstrel_vht_only, bool, 0644);
198 MODULE_PARM_DESC(minstrel_vht_only,
199 		 "Use only VHT rates when VHT is supported by sta.");
200 
201 /*
202  * To enable sufficiently targeted rate sampling, MCS rates are divided into
203  * groups, based on the number of streams and flags (HT40, SGI) that they
204  * use.
205  *
206  * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
207  * BW -> SGI -> #streams
208  */
209 const struct mcs_group minstrel_mcs_groups[] = {
210 	MCS_GROUP(1, 0, BW_20),
211 	MCS_GROUP(2, 0, BW_20),
212 	MCS_GROUP(3, 0, BW_20),
213 	MCS_GROUP(4, 0, BW_20),
214 
215 	MCS_GROUP(1, 1, BW_20),
216 	MCS_GROUP(2, 1, BW_20),
217 	MCS_GROUP(3, 1, BW_20),
218 	MCS_GROUP(4, 1, BW_20),
219 
220 	MCS_GROUP(1, 0, BW_40),
221 	MCS_GROUP(2, 0, BW_40),
222 	MCS_GROUP(3, 0, BW_40),
223 	MCS_GROUP(4, 0, BW_40),
224 
225 	MCS_GROUP(1, 1, BW_40),
226 	MCS_GROUP(2, 1, BW_40),
227 	MCS_GROUP(3, 1, BW_40),
228 	MCS_GROUP(4, 1, BW_40),
229 
230 	CCK_GROUP,
231 	OFDM_GROUP,
232 
233 	VHT_GROUP(1, 0, BW_20),
234 	VHT_GROUP(2, 0, BW_20),
235 	VHT_GROUP(3, 0, BW_20),
236 	VHT_GROUP(4, 0, BW_20),
237 
238 	VHT_GROUP(1, 1, BW_20),
239 	VHT_GROUP(2, 1, BW_20),
240 	VHT_GROUP(3, 1, BW_20),
241 	VHT_GROUP(4, 1, BW_20),
242 
243 	VHT_GROUP(1, 0, BW_40),
244 	VHT_GROUP(2, 0, BW_40),
245 	VHT_GROUP(3, 0, BW_40),
246 	VHT_GROUP(4, 0, BW_40),
247 
248 	VHT_GROUP(1, 1, BW_40),
249 	VHT_GROUP(2, 1, BW_40),
250 	VHT_GROUP(3, 1, BW_40),
251 	VHT_GROUP(4, 1, BW_40),
252 
253 	VHT_GROUP(1, 0, BW_80),
254 	VHT_GROUP(2, 0, BW_80),
255 	VHT_GROUP(3, 0, BW_80),
256 	VHT_GROUP(4, 0, BW_80),
257 
258 	VHT_GROUP(1, 1, BW_80),
259 	VHT_GROUP(2, 1, BW_80),
260 	VHT_GROUP(3, 1, BW_80),
261 	VHT_GROUP(4, 1, BW_80),
262 };
263 
264 const s16 minstrel_cck_bitrates[4] = { 10, 20, 55, 110 };
265 const s16 minstrel_ofdm_bitrates[8] = { 60, 90, 120, 180, 240, 360, 480, 540 };
266 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
267 static const u8 minstrel_sample_seq[] = {
268 	MINSTREL_SAMPLE_TYPE_INC,
269 	MINSTREL_SAMPLE_TYPE_JUMP,
270 	MINSTREL_SAMPLE_TYPE_INC,
271 	MINSTREL_SAMPLE_TYPE_JUMP,
272 	MINSTREL_SAMPLE_TYPE_INC,
273 	MINSTREL_SAMPLE_TYPE_SLOW,
274 };
275 
276 static void
277 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
278 
279 /*
280  * Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
281  * e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
282  *
283  * Returns the valid mcs map for struct minstrel_mcs_group_data.supported
284  */
285 static u16
minstrel_get_valid_vht_rates(int bw,int nss,__le16 mcs_map)286 minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
287 {
288 	u16 mask = 0;
289 
290 	if (bw == BW_20) {
291 		if (nss != 3 && nss != 6)
292 			mask = BIT(9);
293 	} else if (bw == BW_80) {
294 		if (nss == 3 || nss == 7)
295 			mask = BIT(6);
296 		else if (nss == 6)
297 			mask = BIT(9);
298 	} else {
299 		WARN_ON(bw != BW_40);
300 	}
301 
302 	switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
303 	case IEEE80211_VHT_MCS_SUPPORT_0_7:
304 		mask |= 0x300;
305 		break;
306 	case IEEE80211_VHT_MCS_SUPPORT_0_8:
307 		mask |= 0x200;
308 		break;
309 	case IEEE80211_VHT_MCS_SUPPORT_0_9:
310 		break;
311 	default:
312 		mask = 0x3ff;
313 	}
314 
315 	return 0x3ff & ~mask;
316 }
317 
318 static bool
minstrel_ht_is_legacy_group(int group)319 minstrel_ht_is_legacy_group(int group)
320 {
321 	return group == MINSTREL_CCK_GROUP ||
322 	       group == MINSTREL_OFDM_GROUP;
323 }
324 
325 /*
326  * Look up an MCS group index based on mac80211 rate information
327  */
328 static int
minstrel_ht_get_group_idx(struct ieee80211_tx_rate * rate)329 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
330 {
331 	return GROUP_IDX((rate->idx / 8) + 1,
332 			 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
333 			 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
334 }
335 
336 /*
337  * Look up an MCS group index based on new cfg80211 rate_info.
338  */
339 static int
minstrel_ht_ri_get_group_idx(struct rate_info * rate)340 minstrel_ht_ri_get_group_idx(struct rate_info *rate)
341 {
342 	return GROUP_IDX((rate->mcs / 8) + 1,
343 			 !!(rate->flags & RATE_INFO_FLAGS_SHORT_GI),
344 			 !!(rate->bw & RATE_INFO_BW_40));
345 }
346 
347 static int
minstrel_vht_get_group_idx(struct ieee80211_tx_rate * rate)348 minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
349 {
350 	return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
351 			     !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
352 			     !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
353 			     2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
354 }
355 
356 /*
357  * Look up an MCS group index based on new cfg80211 rate_info.
358  */
359 static int
minstrel_vht_ri_get_group_idx(struct rate_info * rate)360 minstrel_vht_ri_get_group_idx(struct rate_info *rate)
361 {
362 	return VHT_GROUP_IDX(rate->nss,
363 			     !!(rate->flags & RATE_INFO_FLAGS_SHORT_GI),
364 			     !!(rate->bw & RATE_INFO_BW_40) +
365 			     2*!!(rate->bw & RATE_INFO_BW_80));
366 }
367 
368 static struct minstrel_rate_stats *
minstrel_ht_get_stats(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,struct ieee80211_tx_rate * rate)369 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
370 		      struct ieee80211_tx_rate *rate)
371 {
372 	int group, idx;
373 
374 	if (rate->flags & IEEE80211_TX_RC_MCS) {
375 		group = minstrel_ht_get_group_idx(rate);
376 		idx = rate->idx % 8;
377 		goto out;
378 	}
379 
380 	if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
381 		group = minstrel_vht_get_group_idx(rate);
382 		idx = ieee80211_rate_get_vht_mcs(rate);
383 		goto out;
384 	}
385 
386 	group = MINSTREL_CCK_GROUP;
387 	for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++) {
388 		if (!(mi->supported[group] & BIT(idx)))
389 			continue;
390 
391 		if (rate->idx != mp->cck_rates[idx])
392 			continue;
393 
394 		/* short preamble */
395 		if ((mi->supported[group] & BIT(idx + 4)) &&
396 		    (rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE))
397 			idx += 4;
398 		goto out;
399 	}
400 
401 	group = MINSTREL_OFDM_GROUP;
402 	for (idx = 0; idx < ARRAY_SIZE(mp->ofdm_rates[0]); idx++)
403 		if (rate->idx == mp->ofdm_rates[mi->band][idx])
404 			goto out;
405 
406 	idx = 0;
407 out:
408 	return &mi->groups[group].rates[idx];
409 }
410 
411 /*
412  * Get the minstrel rate statistics for specified STA and rate info.
413  */
414 static struct minstrel_rate_stats *
minstrel_ht_ri_get_stats(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,struct ieee80211_rate_status * rate_status)415 minstrel_ht_ri_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
416 			  struct ieee80211_rate_status *rate_status)
417 {
418 	int group, idx;
419 	struct rate_info *rate = &rate_status->rate_idx;
420 
421 	if (rate->flags & RATE_INFO_FLAGS_MCS) {
422 		group = minstrel_ht_ri_get_group_idx(rate);
423 		idx = rate->mcs % 8;
424 		goto out;
425 	}
426 
427 	if (rate->flags & RATE_INFO_FLAGS_VHT_MCS) {
428 		group = minstrel_vht_ri_get_group_idx(rate);
429 		idx = rate->mcs;
430 		goto out;
431 	}
432 
433 	group = MINSTREL_CCK_GROUP;
434 	for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++) {
435 		if (rate->legacy != minstrel_cck_bitrates[ mp->cck_rates[idx] ])
436 			continue;
437 
438 		/* short preamble */
439 		if ((mi->supported[group] & BIT(idx + 4)) &&
440 							mi->use_short_preamble)
441 			idx += 4;
442 		goto out;
443 	}
444 
445 	group = MINSTREL_OFDM_GROUP;
446 	for (idx = 0; idx < ARRAY_SIZE(mp->ofdm_rates[0]); idx++)
447 		if (rate->legacy == minstrel_ofdm_bitrates[ mp->ofdm_rates[mi->band][idx] ])
448 			goto out;
449 
450 	idx = 0;
451 out:
452 	return &mi->groups[group].rates[idx];
453 }
454 
455 static inline struct minstrel_rate_stats *
minstrel_get_ratestats(struct minstrel_ht_sta * mi,int index)456 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
457 {
458 	return &mi->groups[MI_RATE_GROUP(index)].rates[MI_RATE_IDX(index)];
459 }
460 
minstrel_get_duration(int index)461 static inline int minstrel_get_duration(int index)
462 {
463 	const struct mcs_group *group = &minstrel_mcs_groups[MI_RATE_GROUP(index)];
464 	unsigned int duration = group->duration[MI_RATE_IDX(index)];
465 
466 	return duration << group->shift;
467 }
468 
469 static unsigned int
minstrel_ht_avg_ampdu_len(struct minstrel_ht_sta * mi)470 minstrel_ht_avg_ampdu_len(struct minstrel_ht_sta *mi)
471 {
472 	int duration;
473 
474 	if (mi->avg_ampdu_len)
475 		return MINSTREL_TRUNC(mi->avg_ampdu_len);
476 
477 	if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(mi->max_tp_rate[0])))
478 		return 1;
479 
480 	duration = minstrel_get_duration(mi->max_tp_rate[0]);
481 
482 	if (duration > 400 * 1000)
483 		return 2;
484 
485 	if (duration > 250 * 1000)
486 		return 4;
487 
488 	if (duration > 150 * 1000)
489 		return 8;
490 
491 	return 16;
492 }
493 
494 /*
495  * Return current throughput based on the average A-MPDU length, taking into
496  * account the expected number of retransmissions and their expected length
497  */
498 int
minstrel_ht_get_tp_avg(struct minstrel_ht_sta * mi,int group,int rate,int prob_avg)499 minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate,
500 		       int prob_avg)
501 {
502 	unsigned int nsecs = 0, overhead = mi->overhead;
503 	unsigned int ampdu_len = 1;
504 
505 	/* do not account throughput if success prob is below 10% */
506 	if (prob_avg < MINSTREL_FRAC(10, 100))
507 		return 0;
508 
509 	if (minstrel_ht_is_legacy_group(group))
510 		overhead = mi->overhead_legacy;
511 	else
512 		ampdu_len = minstrel_ht_avg_ampdu_len(mi);
513 
514 	nsecs = 1000 * overhead / ampdu_len;
515 	nsecs += minstrel_mcs_groups[group].duration[rate] <<
516 		 minstrel_mcs_groups[group].shift;
517 
518 	/*
519 	 * For the throughput calculation, limit the probability value to 90% to
520 	 * account for collision related packet error rate fluctuation
521 	 * (prob is scaled - see MINSTREL_FRAC above)
522 	 */
523 	if (prob_avg > MINSTREL_FRAC(90, 100))
524 		prob_avg = MINSTREL_FRAC(90, 100);
525 
526 	return MINSTREL_TRUNC(100 * ((prob_avg * 1000000) / nsecs));
527 }
528 
529 /*
530  * Find & sort topmost throughput rates
531  *
532  * If multiple rates provide equal throughput the sorting is based on their
533  * current success probability. Higher success probability is preferred among
534  * MCS groups, CCK rates do not provide aggregation and are therefore at last.
535  */
536 static void
minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta * mi,u16 index,u16 * tp_list)537 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
538 			       u16 *tp_list)
539 {
540 	int cur_group, cur_idx, cur_tp_avg, cur_prob;
541 	int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
542 	int j = MAX_THR_RATES;
543 
544 	cur_group = MI_RATE_GROUP(index);
545 	cur_idx = MI_RATE_IDX(index);
546 	cur_prob = mi->groups[cur_group].rates[cur_idx].prob_avg;
547 	cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob);
548 
549 	do {
550 		tmp_group = MI_RATE_GROUP(tp_list[j - 1]);
551 		tmp_idx = MI_RATE_IDX(tp_list[j - 1]);
552 		tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
553 		tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx,
554 						    tmp_prob);
555 		if (cur_tp_avg < tmp_tp_avg ||
556 		    (cur_tp_avg == tmp_tp_avg && cur_prob <= tmp_prob))
557 			break;
558 		j--;
559 	} while (j > 0);
560 
561 	if (j < MAX_THR_RATES - 1) {
562 		memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
563 		       (MAX_THR_RATES - (j + 1))));
564 	}
565 	if (j < MAX_THR_RATES)
566 		tp_list[j] = index;
567 }
568 
569 /*
570  * Find and set the topmost probability rate per sta and per group
571  */
572 static void
minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta * mi,u16 * dest,u16 index)573 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 *dest, u16 index)
574 {
575 	struct minstrel_mcs_group_data *mg;
576 	struct minstrel_rate_stats *mrs;
577 	int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
578 	int max_tp_group, max_tp_idx, max_tp_prob;
579 	int cur_tp_avg, cur_group, cur_idx;
580 	int max_gpr_group, max_gpr_idx;
581 	int max_gpr_tp_avg, max_gpr_prob;
582 
583 	cur_group = MI_RATE_GROUP(index);
584 	cur_idx = MI_RATE_IDX(index);
585 	mg = &mi->groups[cur_group];
586 	mrs = &mg->rates[cur_idx];
587 
588 	tmp_group = MI_RATE_GROUP(*dest);
589 	tmp_idx = MI_RATE_IDX(*dest);
590 	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
591 	tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
592 
593 	/* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
594 	 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
595 	max_tp_group = MI_RATE_GROUP(mi->max_tp_rate[0]);
596 	max_tp_idx = MI_RATE_IDX(mi->max_tp_rate[0]);
597 	max_tp_prob = mi->groups[max_tp_group].rates[max_tp_idx].prob_avg;
598 
599 	if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(index)) &&
600 	    !minstrel_ht_is_legacy_group(max_tp_group))
601 		return;
602 
603 	/* skip rates faster than max tp rate with lower prob */
604 	if (minstrel_get_duration(mi->max_tp_rate[0]) > minstrel_get_duration(index) &&
605 	    mrs->prob_avg < max_tp_prob)
606 		return;
607 
608 	max_gpr_group = MI_RATE_GROUP(mg->max_group_prob_rate);
609 	max_gpr_idx = MI_RATE_IDX(mg->max_group_prob_rate);
610 	max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_avg;
611 
612 	if (mrs->prob_avg > MINSTREL_FRAC(75, 100)) {
613 		cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx,
614 						    mrs->prob_avg);
615 		if (cur_tp_avg > tmp_tp_avg)
616 			*dest = index;
617 
618 		max_gpr_tp_avg = minstrel_ht_get_tp_avg(mi, max_gpr_group,
619 							max_gpr_idx,
620 							max_gpr_prob);
621 		if (cur_tp_avg > max_gpr_tp_avg)
622 			mg->max_group_prob_rate = index;
623 	} else {
624 		if (mrs->prob_avg > tmp_prob)
625 			*dest = index;
626 		if (mrs->prob_avg > max_gpr_prob)
627 			mg->max_group_prob_rate = index;
628 	}
629 }
630 
631 
632 /*
633  * Assign new rate set per sta and use CCK rates only if the fastest
634  * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
635  * rate sets where MCS and CCK rates are mixed, because CCK rates can
636  * not use aggregation.
637  */
638 static void
minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta * mi,u16 tmp_mcs_tp_rate[MAX_THR_RATES],u16 tmp_legacy_tp_rate[MAX_THR_RATES])639 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
640 				 u16 tmp_mcs_tp_rate[MAX_THR_RATES],
641 				 u16 tmp_legacy_tp_rate[MAX_THR_RATES])
642 {
643 	unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob;
644 	int i;
645 
646 	tmp_group = MI_RATE_GROUP(tmp_legacy_tp_rate[0]);
647 	tmp_idx = MI_RATE_IDX(tmp_legacy_tp_rate[0]);
648 	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
649 	tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
650 
651 	tmp_group = MI_RATE_GROUP(tmp_mcs_tp_rate[0]);
652 	tmp_idx = MI_RATE_IDX(tmp_mcs_tp_rate[0]);
653 	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
654 	tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
655 
656 	if (tmp_cck_tp > tmp_mcs_tp) {
657 		for(i = 0; i < MAX_THR_RATES; i++) {
658 			minstrel_ht_sort_best_tp_rates(mi, tmp_legacy_tp_rate[i],
659 						       tmp_mcs_tp_rate);
660 		}
661 	}
662 
663 }
664 
665 /*
666  * Try to increase robustness of max_prob rate by decrease number of
667  * streams if possible.
668  */
669 static inline void
minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta * mi)670 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
671 {
672 	struct minstrel_mcs_group_data *mg;
673 	int tmp_max_streams, group, tmp_idx, tmp_prob;
674 	int tmp_tp = 0;
675 
676 	if (!mi->sta->deflink.ht_cap.ht_supported)
677 		return;
678 
679 	group = MI_RATE_GROUP(mi->max_tp_rate[0]);
680 	tmp_max_streams = minstrel_mcs_groups[group].streams;
681 	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
682 		mg = &mi->groups[group];
683 		if (!mi->supported[group] || group == MINSTREL_CCK_GROUP)
684 			continue;
685 
686 		tmp_idx = MI_RATE_IDX(mg->max_group_prob_rate);
687 		tmp_prob = mi->groups[group].rates[tmp_idx].prob_avg;
688 
689 		if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx, tmp_prob) &&
690 		   (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
691 				mi->max_prob_rate = mg->max_group_prob_rate;
692 				tmp_tp = minstrel_ht_get_tp_avg(mi, group,
693 								tmp_idx,
694 								tmp_prob);
695 		}
696 	}
697 }
698 
699 static u16
__minstrel_ht_get_sample_rate(struct minstrel_ht_sta * mi,enum minstrel_sample_type type)700 __minstrel_ht_get_sample_rate(struct minstrel_ht_sta *mi,
701 			      enum minstrel_sample_type type)
702 {
703 	u16 *rates = mi->sample[type].sample_rates;
704 	u16 cur;
705 	int i;
706 
707 	for (i = 0; i < MINSTREL_SAMPLE_RATES; i++) {
708 		if (!rates[i])
709 			continue;
710 
711 		cur = rates[i];
712 		rates[i] = 0;
713 		return cur;
714 	}
715 
716 	return 0;
717 }
718 
719 static inline int
minstrel_ewma(int old,int new,int weight)720 minstrel_ewma(int old, int new, int weight)
721 {
722 	int diff, incr;
723 
724 	diff = new - old;
725 	incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
726 
727 	return old + incr;
728 }
729 
minstrel_filter_avg_add(u16 * prev_1,u16 * prev_2,s32 in)730 static inline int minstrel_filter_avg_add(u16 *prev_1, u16 *prev_2, s32 in)
731 {
732 	s32 out_1 = *prev_1;
733 	s32 out_2 = *prev_2;
734 	s32 val;
735 
736 	if (!in)
737 		in += 1;
738 
739 	if (!out_1) {
740 		val = out_1 = in;
741 		goto out;
742 	}
743 
744 	val = MINSTREL_AVG_COEFF1 * in;
745 	val += MINSTREL_AVG_COEFF2 * out_1;
746 	val += MINSTREL_AVG_COEFF3 * out_2;
747 	val >>= MINSTREL_SCALE;
748 
749 	if (val > 1 << MINSTREL_SCALE)
750 		val = 1 << MINSTREL_SCALE;
751 	if (val < 0)
752 		val = 1;
753 
754 out:
755 	*prev_2 = out_1;
756 	*prev_1 = val;
757 
758 	return val;
759 }
760 
761 /*
762 * Recalculate statistics and counters of a given rate
763 */
764 static void
minstrel_ht_calc_rate_stats(struct minstrel_priv * mp,struct minstrel_rate_stats * mrs)765 minstrel_ht_calc_rate_stats(struct minstrel_priv *mp,
766 			    struct minstrel_rate_stats *mrs)
767 {
768 	unsigned int cur_prob;
769 
770 	if (unlikely(mrs->attempts > 0)) {
771 		cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
772 		minstrel_filter_avg_add(&mrs->prob_avg,
773 					&mrs->prob_avg_1, cur_prob);
774 		mrs->att_hist += mrs->attempts;
775 		mrs->succ_hist += mrs->success;
776 	}
777 
778 	mrs->last_success = mrs->success;
779 	mrs->last_attempts = mrs->attempts;
780 	mrs->success = 0;
781 	mrs->attempts = 0;
782 }
783 
784 static bool
minstrel_ht_find_sample_rate(struct minstrel_ht_sta * mi,int type,int idx)785 minstrel_ht_find_sample_rate(struct minstrel_ht_sta *mi, int type, int idx)
786 {
787 	int i;
788 
789 	for (i = 0; i < MINSTREL_SAMPLE_RATES; i++) {
790 		u16 cur = mi->sample[type].sample_rates[i];
791 
792 		if (cur == idx)
793 			return true;
794 
795 		if (!cur)
796 			break;
797 	}
798 
799 	return false;
800 }
801 
802 static int
minstrel_ht_move_sample_rates(struct minstrel_ht_sta * mi,int type,u32 fast_rate_dur,u32 slow_rate_dur)803 minstrel_ht_move_sample_rates(struct minstrel_ht_sta *mi, int type,
804 			      u32 fast_rate_dur, u32 slow_rate_dur)
805 {
806 	u16 *rates = mi->sample[type].sample_rates;
807 	int i, j;
808 
809 	for (i = 0, j = 0; i < MINSTREL_SAMPLE_RATES; i++) {
810 		u32 duration;
811 		bool valid = false;
812 		u16 cur;
813 
814 		cur = rates[i];
815 		if (!cur)
816 			continue;
817 
818 		duration = minstrel_get_duration(cur);
819 		switch (type) {
820 		case MINSTREL_SAMPLE_TYPE_SLOW:
821 			valid = duration > fast_rate_dur &&
822 				duration < slow_rate_dur;
823 			break;
824 		case MINSTREL_SAMPLE_TYPE_INC:
825 		case MINSTREL_SAMPLE_TYPE_JUMP:
826 			valid = duration < fast_rate_dur;
827 			break;
828 		default:
829 			valid = false;
830 			break;
831 		}
832 
833 		if (!valid) {
834 			rates[i] = 0;
835 			continue;
836 		}
837 
838 		if (i == j)
839 			continue;
840 
841 		rates[j++] = cur;
842 		rates[i] = 0;
843 	}
844 
845 	return j;
846 }
847 
848 static int
minstrel_ht_group_min_rate_offset(struct minstrel_ht_sta * mi,int group,u32 max_duration)849 minstrel_ht_group_min_rate_offset(struct minstrel_ht_sta *mi, int group,
850 				  u32 max_duration)
851 {
852 	u16 supported = mi->supported[group];
853 	int i;
854 
855 	for (i = 0; i < MCS_GROUP_RATES && supported; i++, supported >>= 1) {
856 		if (!(supported & BIT(0)))
857 			continue;
858 
859 		if (minstrel_get_duration(MI_RATE(group, i)) >= max_duration)
860 			continue;
861 
862 		return i;
863 	}
864 
865 	return -1;
866 }
867 
868 /*
869  * Incremental update rates:
870  * Flip through groups and pick the first group rate that is faster than the
871  * highest currently selected rate
872  */
873 static u16
minstrel_ht_next_inc_rate(struct minstrel_ht_sta * mi,u32 fast_rate_dur)874 minstrel_ht_next_inc_rate(struct minstrel_ht_sta *mi, u32 fast_rate_dur)
875 {
876 	u8 type = MINSTREL_SAMPLE_TYPE_INC;
877 	int i, index = 0;
878 	u8 group;
879 
880 	group = mi->sample[type].sample_group;
881 	for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
882 		group = (group + 1) % ARRAY_SIZE(minstrel_mcs_groups);
883 
884 		index = minstrel_ht_group_min_rate_offset(mi, group,
885 							  fast_rate_dur);
886 		if (index < 0)
887 			continue;
888 
889 		index = MI_RATE(group, index & 0xf);
890 		if (!minstrel_ht_find_sample_rate(mi, type, index))
891 			goto out;
892 	}
893 	index = 0;
894 
895 out:
896 	mi->sample[type].sample_group = group;
897 
898 	return index;
899 }
900 
901 static int
minstrel_ht_next_group_sample_rate(struct minstrel_ht_sta * mi,int group,u16 supported,int offset)902 minstrel_ht_next_group_sample_rate(struct minstrel_ht_sta *mi, int group,
903 				   u16 supported, int offset)
904 {
905 	struct minstrel_mcs_group_data *mg = &mi->groups[group];
906 	u16 idx;
907 	int i;
908 
909 	for (i = 0; i < MCS_GROUP_RATES; i++) {
910 		idx = sample_table[mg->column][mg->index];
911 		if (++mg->index >= MCS_GROUP_RATES) {
912 			mg->index = 0;
913 			if (++mg->column >= ARRAY_SIZE(sample_table))
914 				mg->column = 0;
915 		}
916 
917 		if (idx < offset)
918 			continue;
919 
920 		if (!(supported & BIT(idx)))
921 			continue;
922 
923 		return MI_RATE(group, idx);
924 	}
925 
926 	return -1;
927 }
928 
929 /*
930  * Jump rates:
931  * Sample random rates, use those that are faster than the highest
932  * currently selected rate. Rates between the fastest and the slowest
933  * get sorted into the slow sample bucket, but only if it has room
934  */
935 static u16
minstrel_ht_next_jump_rate(struct minstrel_ht_sta * mi,u32 fast_rate_dur,u32 slow_rate_dur,int * slow_rate_ofs)936 minstrel_ht_next_jump_rate(struct minstrel_ht_sta *mi, u32 fast_rate_dur,
937 			   u32 slow_rate_dur, int *slow_rate_ofs)
938 {
939 	struct minstrel_rate_stats *mrs;
940 	u32 max_duration = slow_rate_dur;
941 	int i, index, offset;
942 	u16 *slow_rates;
943 	u16 supported;
944 	u32 duration;
945 	u8 group;
946 
947 	if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
948 		max_duration = fast_rate_dur;
949 
950 	slow_rates = mi->sample[MINSTREL_SAMPLE_TYPE_SLOW].sample_rates;
951 	group = mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_group;
952 	for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
953 		u8 type;
954 
955 		group = (group + 1) % ARRAY_SIZE(minstrel_mcs_groups);
956 
957 		supported = mi->supported[group];
958 		if (!supported)
959 			continue;
960 
961 		offset = minstrel_ht_group_min_rate_offset(mi, group,
962 							   max_duration);
963 		if (offset < 0)
964 			continue;
965 
966 		index = minstrel_ht_next_group_sample_rate(mi, group, supported,
967 							   offset);
968 		if (index < 0)
969 			continue;
970 
971 		duration = minstrel_get_duration(index);
972 		if (duration < fast_rate_dur)
973 			type = MINSTREL_SAMPLE_TYPE_JUMP;
974 		else
975 			type = MINSTREL_SAMPLE_TYPE_SLOW;
976 
977 		if (minstrel_ht_find_sample_rate(mi, type, index))
978 			continue;
979 
980 		if (type == MINSTREL_SAMPLE_TYPE_JUMP)
981 			goto found;
982 
983 		if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
984 			continue;
985 
986 		if (duration >= slow_rate_dur)
987 			continue;
988 
989 		/* skip slow rates with high success probability */
990 		mrs = minstrel_get_ratestats(mi, index);
991 		if (mrs->prob_avg > MINSTREL_FRAC(95, 100))
992 			continue;
993 
994 		slow_rates[(*slow_rate_ofs)++] = index;
995 		if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
996 			max_duration = fast_rate_dur;
997 	}
998 	index = 0;
999 
1000 found:
1001 	mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_group = group;
1002 
1003 	return index;
1004 }
1005 
1006 static void
minstrel_ht_refill_sample_rates(struct minstrel_ht_sta * mi)1007 minstrel_ht_refill_sample_rates(struct minstrel_ht_sta *mi)
1008 {
1009 	u32 prob_dur = minstrel_get_duration(mi->max_prob_rate);
1010 	u32 tp_dur = minstrel_get_duration(mi->max_tp_rate[0]);
1011 	u32 tp2_dur = minstrel_get_duration(mi->max_tp_rate[1]);
1012 	u32 fast_rate_dur = min(min(tp_dur, tp2_dur), prob_dur);
1013 	u32 slow_rate_dur = max(max(tp_dur, tp2_dur), prob_dur);
1014 	u16 *rates;
1015 	int i, j;
1016 
1017 	rates = mi->sample[MINSTREL_SAMPLE_TYPE_INC].sample_rates;
1018 	i = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_INC,
1019 					  fast_rate_dur, slow_rate_dur);
1020 	while (i < MINSTREL_SAMPLE_RATES) {
1021 		rates[i] = minstrel_ht_next_inc_rate(mi, tp_dur);
1022 		if (!rates[i])
1023 			break;
1024 
1025 		i++;
1026 	}
1027 
1028 	rates = mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_rates;
1029 	i = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_JUMP,
1030 					  fast_rate_dur, slow_rate_dur);
1031 	j = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_SLOW,
1032 					  fast_rate_dur, slow_rate_dur);
1033 	while (i < MINSTREL_SAMPLE_RATES) {
1034 		rates[i] = minstrel_ht_next_jump_rate(mi, fast_rate_dur,
1035 						      slow_rate_dur, &j);
1036 		if (!rates[i])
1037 			break;
1038 
1039 		i++;
1040 	}
1041 
1042 	for (i = 0; i < ARRAY_SIZE(mi->sample); i++)
1043 		memcpy(mi->sample[i].cur_sample_rates, mi->sample[i].sample_rates,
1044 		       sizeof(mi->sample[i].cur_sample_rates));
1045 }
1046 
1047 
1048 /*
1049  * Update rate statistics and select new primary rates
1050  *
1051  * Rules for rate selection:
1052  *  - max_prob_rate must use only one stream, as a tradeoff between delivery
1053  *    probability and throughput during strong fluctuations
1054  *  - as long as the max prob rate has a probability of more than 75%, pick
1055  *    higher throughput rates, even if the probablity is a bit lower
1056  */
1057 static void
minstrel_ht_update_stats(struct minstrel_priv * mp,struct minstrel_ht_sta * mi)1058 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
1059 {
1060 	struct minstrel_mcs_group_data *mg;
1061 	struct minstrel_rate_stats *mrs;
1062 	int group, i, j, cur_prob;
1063 	u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
1064 	u16 tmp_legacy_tp_rate[MAX_THR_RATES], tmp_max_prob_rate;
1065 	u16 index;
1066 	bool ht_supported = mi->sta->deflink.ht_cap.ht_supported;
1067 
1068 	if (mi->ampdu_packets > 0) {
1069 		if (!ieee80211_hw_check(mp->hw, TX_STATUS_NO_AMPDU_LEN))
1070 			mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
1071 				MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets),
1072 					      EWMA_LEVEL);
1073 		else
1074 			mi->avg_ampdu_len = 0;
1075 		mi->ampdu_len = 0;
1076 		mi->ampdu_packets = 0;
1077 	}
1078 
1079 	if (mi->supported[MINSTREL_CCK_GROUP])
1080 		group = MINSTREL_CCK_GROUP;
1081 	else if (mi->supported[MINSTREL_OFDM_GROUP])
1082 		group = MINSTREL_OFDM_GROUP;
1083 	else
1084 		group = 0;
1085 
1086 	index = MI_RATE(group, 0);
1087 	for (j = 0; j < ARRAY_SIZE(tmp_legacy_tp_rate); j++)
1088 		tmp_legacy_tp_rate[j] = index;
1089 
1090 	if (mi->supported[MINSTREL_VHT_GROUP_0])
1091 		group = MINSTREL_VHT_GROUP_0;
1092 	else if (ht_supported)
1093 		group = MINSTREL_HT_GROUP_0;
1094 	else if (mi->supported[MINSTREL_CCK_GROUP])
1095 		group = MINSTREL_CCK_GROUP;
1096 	else
1097 		group = MINSTREL_OFDM_GROUP;
1098 
1099 	index = MI_RATE(group, 0);
1100 	tmp_max_prob_rate = index;
1101 	for (j = 0; j < ARRAY_SIZE(tmp_mcs_tp_rate); j++)
1102 		tmp_mcs_tp_rate[j] = index;
1103 
1104 	/* Find best rate sets within all MCS groups*/
1105 	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
1106 		u16 *tp_rate = tmp_mcs_tp_rate;
1107 		u16 last_prob = 0;
1108 
1109 		mg = &mi->groups[group];
1110 		if (!mi->supported[group])
1111 			continue;
1112 
1113 		/* (re)Initialize group rate indexes */
1114 		for(j = 0; j < MAX_THR_RATES; j++)
1115 			tmp_group_tp_rate[j] = MI_RATE(group, 0);
1116 
1117 		if (group == MINSTREL_CCK_GROUP && ht_supported)
1118 			tp_rate = tmp_legacy_tp_rate;
1119 
1120 		for (i = MCS_GROUP_RATES - 1; i >= 0; i--) {
1121 			if (!(mi->supported[group] & BIT(i)))
1122 				continue;
1123 
1124 			index = MI_RATE(group, i);
1125 
1126 			mrs = &mg->rates[i];
1127 			mrs->retry_updated = false;
1128 			minstrel_ht_calc_rate_stats(mp, mrs);
1129 
1130 			if (mrs->att_hist)
1131 				last_prob = max(last_prob, mrs->prob_avg);
1132 			else
1133 				mrs->prob_avg = max(last_prob, mrs->prob_avg);
1134 			cur_prob = mrs->prob_avg;
1135 
1136 			if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
1137 				continue;
1138 
1139 			/* Find max throughput rate set */
1140 			minstrel_ht_sort_best_tp_rates(mi, index, tp_rate);
1141 
1142 			/* Find max throughput rate set within a group */
1143 			minstrel_ht_sort_best_tp_rates(mi, index,
1144 						       tmp_group_tp_rate);
1145 		}
1146 
1147 		memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
1148 		       sizeof(mg->max_group_tp_rate));
1149 	}
1150 
1151 	/* Assign new rate set per sta */
1152 	minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate,
1153 					 tmp_legacy_tp_rate);
1154 	memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
1155 
1156 	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
1157 		if (!mi->supported[group])
1158 			continue;
1159 
1160 		mg = &mi->groups[group];
1161 		mg->max_group_prob_rate = MI_RATE(group, 0);
1162 
1163 		for (i = 0; i < MCS_GROUP_RATES; i++) {
1164 			if (!(mi->supported[group] & BIT(i)))
1165 				continue;
1166 
1167 			index = MI_RATE(group, i);
1168 
1169 			/* Find max probability rate per group and global */
1170 			minstrel_ht_set_best_prob_rate(mi, &tmp_max_prob_rate,
1171 						       index);
1172 		}
1173 	}
1174 
1175 	mi->max_prob_rate = tmp_max_prob_rate;
1176 
1177 	/* Try to increase robustness of max_prob_rate*/
1178 	minstrel_ht_prob_rate_reduce_streams(mi);
1179 	minstrel_ht_refill_sample_rates(mi);
1180 
1181 #ifdef CONFIG_MAC80211_DEBUGFS
1182 	/* use fixed index if set */
1183 	if (mp->fixed_rate_idx != -1) {
1184 		for (i = 0; i < 4; i++)
1185 			mi->max_tp_rate[i] = mp->fixed_rate_idx;
1186 		mi->max_prob_rate = mp->fixed_rate_idx;
1187 	}
1188 #endif
1189 
1190 	/* Reset update timer */
1191 	mi->last_stats_update = jiffies;
1192 	mi->sample_time = jiffies;
1193 }
1194 
1195 static bool
minstrel_ht_txstat_valid(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,struct ieee80211_tx_rate * rate)1196 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1197 			 struct ieee80211_tx_rate *rate)
1198 {
1199 	int i;
1200 
1201 	if (rate->idx < 0)
1202 		return false;
1203 
1204 	if (!rate->count)
1205 		return false;
1206 
1207 	if (rate->flags & IEEE80211_TX_RC_MCS ||
1208 	    rate->flags & IEEE80211_TX_RC_VHT_MCS)
1209 		return true;
1210 
1211 	for (i = 0; i < ARRAY_SIZE(mp->cck_rates); i++)
1212 		if (rate->idx == mp->cck_rates[i])
1213 			return true;
1214 
1215 	for (i = 0; i < ARRAY_SIZE(mp->ofdm_rates[0]); i++)
1216 		if (rate->idx == mp->ofdm_rates[mi->band][i])
1217 			return true;
1218 
1219 	return false;
1220 }
1221 
1222 /*
1223  * Check whether rate_status contains valid information.
1224  */
1225 static bool
minstrel_ht_ri_txstat_valid(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,struct ieee80211_rate_status * rate_status)1226 minstrel_ht_ri_txstat_valid(struct minstrel_priv *mp,
1227 			    struct minstrel_ht_sta *mi,
1228 			    struct ieee80211_rate_status *rate_status)
1229 {
1230 	int i;
1231 
1232 	if (!rate_status)
1233 		return false;
1234 	if (!rate_status->try_count)
1235 		return false;
1236 
1237 	if (rate_status->rate_idx.flags & RATE_INFO_FLAGS_MCS ||
1238 	    rate_status->rate_idx.flags & RATE_INFO_FLAGS_VHT_MCS)
1239 		return true;
1240 
1241 	for (i = 0; i < ARRAY_SIZE(mp->cck_rates); i++) {
1242 		if (rate_status->rate_idx.legacy ==
1243 		    minstrel_cck_bitrates[ mp->cck_rates[i] ])
1244 			return true;
1245 	}
1246 
1247 	for (i = 0; i < ARRAY_SIZE(mp->ofdm_rates); i++) {
1248 		if (rate_status->rate_idx.legacy ==
1249 		    minstrel_ofdm_bitrates[ mp->ofdm_rates[mi->band][i] ])
1250 			return true;
1251 	}
1252 
1253 	return false;
1254 }
1255 
1256 static void
minstrel_downgrade_rate(struct minstrel_ht_sta * mi,u16 * idx,bool primary)1257 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u16 *idx, bool primary)
1258 {
1259 	int group, orig_group;
1260 
1261 	orig_group = group = MI_RATE_GROUP(*idx);
1262 	while (group > 0) {
1263 		group--;
1264 
1265 		if (!mi->supported[group])
1266 			continue;
1267 
1268 		if (minstrel_mcs_groups[group].streams >
1269 		    minstrel_mcs_groups[orig_group].streams)
1270 			continue;
1271 
1272 		if (primary)
1273 			*idx = mi->groups[group].max_group_tp_rate[0];
1274 		else
1275 			*idx = mi->groups[group].max_group_tp_rate[1];
1276 		break;
1277 	}
1278 }
1279 
1280 static void
minstrel_ht_tx_status(void * priv,struct ieee80211_supported_band * sband,void * priv_sta,struct ieee80211_tx_status * st)1281 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
1282                       void *priv_sta, struct ieee80211_tx_status *st)
1283 {
1284 	struct ieee80211_tx_info *info = st->info;
1285 	struct minstrel_ht_sta *mi = priv_sta;
1286 	struct ieee80211_tx_rate *ar = info->status.rates;
1287 	struct minstrel_rate_stats *rate, *rate2;
1288 	struct minstrel_priv *mp = priv;
1289 	u32 update_interval = mp->update_interval;
1290 	bool last, update = false;
1291 	int i;
1292 
1293 	/* Ignore packet that was sent with noAck flag */
1294 	if (info->flags & IEEE80211_TX_CTL_NO_ACK)
1295 		return;
1296 
1297 	/* This packet was aggregated but doesn't carry status info */
1298 	if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
1299 	    !(info->flags & IEEE80211_TX_STAT_AMPDU))
1300 		return;
1301 
1302 	if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
1303 		info->status.ampdu_ack_len =
1304 			(info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
1305 		info->status.ampdu_len = 1;
1306 	}
1307 
1308 	/* wraparound */
1309 	if (mi->total_packets >= ~0 - info->status.ampdu_len) {
1310 		mi->total_packets = 0;
1311 		mi->sample_packets = 0;
1312 	}
1313 
1314 	mi->total_packets += info->status.ampdu_len;
1315 	if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
1316 		mi->sample_packets += info->status.ampdu_len;
1317 
1318 	mi->ampdu_packets++;
1319 	mi->ampdu_len += info->status.ampdu_len;
1320 
1321 	if (st->rates && st->n_rates) {
1322 		last = !minstrel_ht_ri_txstat_valid(mp, mi, &(st->rates[0]));
1323 		for (i = 0; !last; i++) {
1324 			last = (i == st->n_rates - 1) ||
1325 				!minstrel_ht_ri_txstat_valid(mp, mi,
1326 							&(st->rates[i + 1]));
1327 
1328 			rate = minstrel_ht_ri_get_stats(mp, mi,
1329 							&(st->rates[i]));
1330 
1331 			if (last)
1332 				rate->success += info->status.ampdu_ack_len;
1333 
1334 			rate->attempts += st->rates[i].try_count *
1335 					  info->status.ampdu_len;
1336 		}
1337 	} else {
1338 		last = !minstrel_ht_txstat_valid(mp, mi, &ar[0]);
1339 		for (i = 0; !last; i++) {
1340 			last = (i == IEEE80211_TX_MAX_RATES - 1) ||
1341 				!minstrel_ht_txstat_valid(mp, mi, &ar[i + 1]);
1342 
1343 			rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
1344 			if (last)
1345 				rate->success += info->status.ampdu_ack_len;
1346 
1347 			rate->attempts += ar[i].count * info->status.ampdu_len;
1348 		}
1349 	}
1350 
1351 	if (mp->hw->max_rates > 1) {
1352 		/*
1353 		 * check for sudden death of spatial multiplexing,
1354 		 * downgrade to a lower number of streams if necessary.
1355 		 */
1356 		rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
1357 		if (rate->attempts > 30 &&
1358 		    rate->success < rate->attempts / 4) {
1359 			minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
1360 			update = true;
1361 		}
1362 
1363 		rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
1364 		if (rate2->attempts > 30 &&
1365 		    rate2->success < rate2->attempts / 4) {
1366 			minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
1367 			update = true;
1368 		}
1369 	}
1370 
1371 	if (time_after(jiffies, mi->last_stats_update + update_interval)) {
1372 		update = true;
1373 		minstrel_ht_update_stats(mp, mi);
1374 	}
1375 
1376 	if (update)
1377 		minstrel_ht_update_rates(mp, mi);
1378 }
1379 
1380 static void
minstrel_calc_retransmit(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,int index)1381 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1382                          int index)
1383 {
1384 	struct minstrel_rate_stats *mrs;
1385 	unsigned int tx_time, tx_time_rtscts, tx_time_data;
1386 	unsigned int cw = mp->cw_min;
1387 	unsigned int ctime = 0;
1388 	unsigned int t_slot = 9; /* FIXME */
1389 	unsigned int ampdu_len = minstrel_ht_avg_ampdu_len(mi);
1390 	unsigned int overhead = 0, overhead_rtscts = 0;
1391 
1392 	mrs = minstrel_get_ratestats(mi, index);
1393 	if (mrs->prob_avg < MINSTREL_FRAC(1, 10)) {
1394 		mrs->retry_count = 1;
1395 		mrs->retry_count_rtscts = 1;
1396 		return;
1397 	}
1398 
1399 	mrs->retry_count = 2;
1400 	mrs->retry_count_rtscts = 2;
1401 	mrs->retry_updated = true;
1402 
1403 	tx_time_data = minstrel_get_duration(index) * ampdu_len / 1000;
1404 
1405 	/* Contention time for first 2 tries */
1406 	ctime = (t_slot * cw) >> 1;
1407 	cw = min((cw << 1) | 1, mp->cw_max);
1408 	ctime += (t_slot * cw) >> 1;
1409 	cw = min((cw << 1) | 1, mp->cw_max);
1410 
1411 	if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(index))) {
1412 		overhead = mi->overhead_legacy;
1413 		overhead_rtscts = mi->overhead_legacy_rtscts;
1414 	} else {
1415 		overhead = mi->overhead;
1416 		overhead_rtscts = mi->overhead_rtscts;
1417 	}
1418 
1419 	/* Total TX time for data and Contention after first 2 tries */
1420 	tx_time = ctime + 2 * (overhead + tx_time_data);
1421 	tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
1422 
1423 	/* See how many more tries we can fit inside segment size */
1424 	do {
1425 		/* Contention time for this try */
1426 		ctime = (t_slot * cw) >> 1;
1427 		cw = min((cw << 1) | 1, mp->cw_max);
1428 
1429 		/* Total TX time after this try */
1430 		tx_time += ctime + overhead + tx_time_data;
1431 		tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
1432 
1433 		if (tx_time_rtscts < mp->segment_size)
1434 			mrs->retry_count_rtscts++;
1435 	} while ((tx_time < mp->segment_size) &&
1436 	         (++mrs->retry_count < mp->max_retry));
1437 }
1438 
1439 
1440 static void
minstrel_ht_set_rate(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,struct ieee80211_sta_rates * ratetbl,int offset,int index)1441 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1442                      struct ieee80211_sta_rates *ratetbl, int offset, int index)
1443 {
1444 	int group_idx = MI_RATE_GROUP(index);
1445 	const struct mcs_group *group = &minstrel_mcs_groups[group_idx];
1446 	struct minstrel_rate_stats *mrs;
1447 	u8 idx;
1448 	u16 flags = group->flags;
1449 
1450 	mrs = minstrel_get_ratestats(mi, index);
1451 	if (!mrs->retry_updated)
1452 		minstrel_calc_retransmit(mp, mi, index);
1453 
1454 	if (mrs->prob_avg < MINSTREL_FRAC(20, 100) || !mrs->retry_count) {
1455 		ratetbl->rate[offset].count = 2;
1456 		ratetbl->rate[offset].count_rts = 2;
1457 		ratetbl->rate[offset].count_cts = 2;
1458 	} else {
1459 		ratetbl->rate[offset].count = mrs->retry_count;
1460 		ratetbl->rate[offset].count_cts = mrs->retry_count;
1461 		ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
1462 	}
1463 
1464 	index = MI_RATE_IDX(index);
1465 	if (group_idx == MINSTREL_CCK_GROUP)
1466 		idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
1467 	else if (group_idx == MINSTREL_OFDM_GROUP)
1468 		idx = mp->ofdm_rates[mi->band][index %
1469 					       ARRAY_SIZE(mp->ofdm_rates[0])];
1470 	else if (flags & IEEE80211_TX_RC_VHT_MCS)
1471 		idx = ((group->streams - 1) << 4) |
1472 		      (index & 0xF);
1473 	else
1474 		idx = index + (group->streams - 1) * 8;
1475 
1476 	/* enable RTS/CTS if needed:
1477 	 *  - if station is in dynamic SMPS (and streams > 1)
1478 	 *  - for fallback rates, to increase chances of getting through
1479 	 */
1480 	if (offset > 0 ||
1481 	    (mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
1482 	     group->streams > 1)) {
1483 		ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
1484 		flags |= IEEE80211_TX_RC_USE_RTS_CTS;
1485 	}
1486 
1487 	ratetbl->rate[offset].idx = idx;
1488 	ratetbl->rate[offset].flags = flags;
1489 }
1490 
1491 static inline int
minstrel_ht_get_prob_avg(struct minstrel_ht_sta * mi,int rate)1492 minstrel_ht_get_prob_avg(struct minstrel_ht_sta *mi, int rate)
1493 {
1494 	int group = MI_RATE_GROUP(rate);
1495 	rate = MI_RATE_IDX(rate);
1496 	return mi->groups[group].rates[rate].prob_avg;
1497 }
1498 
1499 static int
minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta * mi)1500 minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
1501 {
1502 	int group = MI_RATE_GROUP(mi->max_prob_rate);
1503 	const struct mcs_group *g = &minstrel_mcs_groups[group];
1504 	int rate = MI_RATE_IDX(mi->max_prob_rate);
1505 	unsigned int duration;
1506 
1507 	/* Disable A-MSDU if max_prob_rate is bad */
1508 	if (mi->groups[group].rates[rate].prob_avg < MINSTREL_FRAC(50, 100))
1509 		return 1;
1510 
1511 	duration = g->duration[rate];
1512 	duration <<= g->shift;
1513 
1514 	/* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
1515 	if (duration > MCS_DURATION(1, 0, 52))
1516 		return 500;
1517 
1518 	/*
1519 	 * If the rate is slower than single-stream MCS4, limit A-MSDU to usual
1520 	 * data packet size
1521 	 */
1522 	if (duration > MCS_DURATION(1, 0, 104))
1523 		return 1600;
1524 
1525 	/*
1526 	 * If the rate is slower than single-stream MCS7, or if the max throughput
1527 	 * rate success probability is less than 75%, limit A-MSDU to twice the usual
1528 	 * data packet size
1529 	 */
1530 	if (duration > MCS_DURATION(1, 0, 260) ||
1531 	    (minstrel_ht_get_prob_avg(mi, mi->max_tp_rate[0]) <
1532 	     MINSTREL_FRAC(75, 100)))
1533 		return 3200;
1534 
1535 	/*
1536 	 * HT A-MPDU limits maximum MPDU size under BA agreement to 4095 bytes.
1537 	 * Since aggregation sessions are started/stopped without txq flush, use
1538 	 * the limit here to avoid the complexity of having to de-aggregate
1539 	 * packets in the queue.
1540 	 */
1541 	if (!mi->sta->deflink.vht_cap.vht_supported)
1542 		return IEEE80211_MAX_MPDU_LEN_HT_BA;
1543 
1544 	/* unlimited */
1545 	return 0;
1546 }
1547 
1548 static void
minstrel_ht_update_rates(struct minstrel_priv * mp,struct minstrel_ht_sta * mi)1549 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
1550 {
1551 	struct ieee80211_sta_rates *rates;
1552 	int i = 0;
1553 
1554 	rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
1555 	if (!rates)
1556 		return;
1557 
1558 	/* Start with max_tp_rate[0] */
1559 	minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
1560 
1561 	/* Fill up remaining, keep one entry for max_probe_rate */
1562 	for (; i < (mp->hw->max_rates - 1); i++)
1563 		minstrel_ht_set_rate(mp, mi, rates, i, mi->max_tp_rate[i]);
1564 
1565 	if (i < mp->hw->max_rates)
1566 		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
1567 
1568 	if (i < IEEE80211_TX_RATE_TABLE_SIZE)
1569 		rates->rate[i].idx = -1;
1570 
1571 	mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi);
1572 	rate_control_set_rates(mp->hw, mi->sta, rates);
1573 }
1574 
1575 static u16
minstrel_ht_get_sample_rate(struct minstrel_priv * mp,struct minstrel_ht_sta * mi)1576 minstrel_ht_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
1577 {
1578 	u8 seq;
1579 
1580 	if (mp->hw->max_rates > 1) {
1581 		seq = mi->sample_seq;
1582 		mi->sample_seq = (seq + 1) % ARRAY_SIZE(minstrel_sample_seq);
1583 		seq = minstrel_sample_seq[seq];
1584 	} else {
1585 		seq = MINSTREL_SAMPLE_TYPE_INC;
1586 	}
1587 
1588 	return __minstrel_ht_get_sample_rate(mi, seq);
1589 }
1590 
1591 static void
minstrel_ht_get_rate(void * priv,struct ieee80211_sta * sta,void * priv_sta,struct ieee80211_tx_rate_control * txrc)1592 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
1593                      struct ieee80211_tx_rate_control *txrc)
1594 {
1595 	const struct mcs_group *sample_group;
1596 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
1597 	struct ieee80211_tx_rate *rate = &info->status.rates[0];
1598 	struct minstrel_ht_sta *mi = priv_sta;
1599 	struct minstrel_priv *mp = priv;
1600 	u16 sample_idx;
1601 
1602 	info->flags |= mi->tx_flags;
1603 
1604 #ifdef CONFIG_MAC80211_DEBUGFS
1605 	if (mp->fixed_rate_idx != -1)
1606 		return;
1607 #endif
1608 
1609 	/* Don't use EAPOL frames for sampling on non-mrr hw */
1610 	if (mp->hw->max_rates == 1 &&
1611 	    (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
1612 		return;
1613 
1614 	if (time_is_after_jiffies(mi->sample_time))
1615 		return;
1616 
1617 	mi->sample_time = jiffies + MINSTREL_SAMPLE_INTERVAL;
1618 	sample_idx = minstrel_ht_get_sample_rate(mp, mi);
1619 	if (!sample_idx)
1620 		return;
1621 
1622 	sample_group = &minstrel_mcs_groups[MI_RATE_GROUP(sample_idx)];
1623 	sample_idx = MI_RATE_IDX(sample_idx);
1624 
1625 	if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP] &&
1626 	    (sample_idx >= 4) != txrc->short_preamble)
1627 		return;
1628 
1629 	info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
1630 	rate->count = 1;
1631 
1632 	if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP]) {
1633 		int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
1634 		rate->idx = mp->cck_rates[idx];
1635 	} else if (sample_group == &minstrel_mcs_groups[MINSTREL_OFDM_GROUP]) {
1636 		int idx = sample_idx % ARRAY_SIZE(mp->ofdm_rates[0]);
1637 		rate->idx = mp->ofdm_rates[mi->band][idx];
1638 	} else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
1639 		ieee80211_rate_set_vht(rate, MI_RATE_IDX(sample_idx),
1640 				       sample_group->streams);
1641 	} else {
1642 		rate->idx = sample_idx + (sample_group->streams - 1) * 8;
1643 	}
1644 
1645 	rate->flags = sample_group->flags;
1646 }
1647 
1648 static void
minstrel_ht_update_cck(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,struct ieee80211_supported_band * sband,struct ieee80211_sta * sta)1649 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1650 		       struct ieee80211_supported_band *sband,
1651 		       struct ieee80211_sta *sta)
1652 {
1653 	int i;
1654 
1655 	if (sband->band != NL80211_BAND_2GHZ)
1656 		return;
1657 
1658 	if (sta->deflink.ht_cap.ht_supported &&
1659 	    !ieee80211_hw_check(mp->hw, SUPPORTS_HT_CCK_RATES))
1660 		return;
1661 
1662 	for (i = 0; i < 4; i++) {
1663 		if (mp->cck_rates[i] == 0xff ||
1664 		    !rate_supported(sta, sband->band, mp->cck_rates[i]))
1665 			continue;
1666 
1667 		mi->supported[MINSTREL_CCK_GROUP] |= BIT(i);
1668 		if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
1669 			mi->supported[MINSTREL_CCK_GROUP] |= BIT(i + 4);
1670 	}
1671 }
1672 
1673 static void
minstrel_ht_update_ofdm(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,struct ieee80211_supported_band * sband,struct ieee80211_sta * sta)1674 minstrel_ht_update_ofdm(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1675 			struct ieee80211_supported_band *sband,
1676 			struct ieee80211_sta *sta)
1677 {
1678 	const u8 *rates;
1679 	int i;
1680 
1681 	if (sta->deflink.ht_cap.ht_supported)
1682 		return;
1683 
1684 	rates = mp->ofdm_rates[sband->band];
1685 	for (i = 0; i < ARRAY_SIZE(mp->ofdm_rates[0]); i++) {
1686 		if (rates[i] == 0xff ||
1687 		    !rate_supported(sta, sband->band, rates[i]))
1688 			continue;
1689 
1690 		mi->supported[MINSTREL_OFDM_GROUP] |= BIT(i);
1691 	}
1692 }
1693 
1694 static void
minstrel_ht_update_caps(void * priv,struct ieee80211_supported_band * sband,struct cfg80211_chan_def * chandef,struct ieee80211_sta * sta,void * priv_sta)1695 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
1696 			struct cfg80211_chan_def *chandef,
1697 			struct ieee80211_sta *sta, void *priv_sta)
1698 {
1699 	struct minstrel_priv *mp = priv;
1700 	struct minstrel_ht_sta *mi = priv_sta;
1701 	struct ieee80211_mcs_info *mcs = &sta->deflink.ht_cap.mcs;
1702 	u16 ht_cap = sta->deflink.ht_cap.cap;
1703 	struct ieee80211_sta_vht_cap *vht_cap = &sta->deflink.vht_cap;
1704 	const struct ieee80211_rate *ctl_rate;
1705 	struct sta_info *sta_info;
1706 	bool ldpc, erp;
1707 	int use_vht;
1708 	int n_supported = 0;
1709 	int ack_dur;
1710 	int stbc;
1711 	int i;
1712 
1713 	BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);
1714 
1715 	if (vht_cap->vht_supported)
1716 		use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
1717 	else
1718 		use_vht = 0;
1719 
1720 	memset(mi, 0, sizeof(*mi));
1721 
1722 	mi->sta = sta;
1723 	mi->band = sband->band;
1724 	mi->last_stats_update = jiffies;
1725 
1726 	ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
1727 	mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
1728 	mi->overhead += ack_dur;
1729 	mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
1730 
1731 	ctl_rate = &sband->bitrates[rate_lowest_index(sband, sta)];
1732 	erp = ctl_rate->flags & IEEE80211_RATE_ERP_G;
1733 	ack_dur = ieee80211_frame_duration(sband->band, 10,
1734 					   ctl_rate->bitrate, erp, 1,
1735 					   ieee80211_chandef_get_shift(chandef));
1736 	mi->overhead_legacy = ack_dur;
1737 	mi->overhead_legacy_rtscts = mi->overhead_legacy + 2 * ack_dur;
1738 
1739 	mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
1740 
1741 	if (!use_vht) {
1742 		stbc = (ht_cap & IEEE80211_HT_CAP_RX_STBC) >>
1743 			IEEE80211_HT_CAP_RX_STBC_SHIFT;
1744 
1745 		ldpc = ht_cap & IEEE80211_HT_CAP_LDPC_CODING;
1746 	} else {
1747 		stbc = (vht_cap->cap & IEEE80211_VHT_CAP_RXSTBC_MASK) >>
1748 			IEEE80211_VHT_CAP_RXSTBC_SHIFT;
1749 
1750 		ldpc = vht_cap->cap & IEEE80211_VHT_CAP_RXLDPC;
1751 	}
1752 
1753 	mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
1754 	if (ldpc)
1755 		mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
1756 
1757 	for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
1758 		u32 gflags = minstrel_mcs_groups[i].flags;
1759 		int bw, nss;
1760 
1761 		mi->supported[i] = 0;
1762 		if (minstrel_ht_is_legacy_group(i))
1763 			continue;
1764 
1765 		if (gflags & IEEE80211_TX_RC_SHORT_GI) {
1766 			if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
1767 				if (!(ht_cap & IEEE80211_HT_CAP_SGI_40))
1768 					continue;
1769 			} else {
1770 				if (!(ht_cap & IEEE80211_HT_CAP_SGI_20))
1771 					continue;
1772 			}
1773 		}
1774 
1775 		if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
1776 		    sta->deflink.bandwidth < IEEE80211_STA_RX_BW_40)
1777 			continue;
1778 
1779 		nss = minstrel_mcs_groups[i].streams;
1780 
1781 		/* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1782 		if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1)
1783 			continue;
1784 
1785 		/* HT rate */
1786 		if (gflags & IEEE80211_TX_RC_MCS) {
1787 			if (use_vht && minstrel_vht_only)
1788 				continue;
1789 
1790 			mi->supported[i] = mcs->rx_mask[nss - 1];
1791 			if (mi->supported[i])
1792 				n_supported++;
1793 			continue;
1794 		}
1795 
1796 		/* VHT rate */
1797 		if (!vht_cap->vht_supported ||
1798 		    WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) ||
1799 		    WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH))
1800 			continue;
1801 
1802 		if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) {
1803 			if (sta->deflink.bandwidth < IEEE80211_STA_RX_BW_80 ||
1804 			    ((gflags & IEEE80211_TX_RC_SHORT_GI) &&
1805 			     !(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) {
1806 				continue;
1807 			}
1808 		}
1809 
1810 		if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
1811 			bw = BW_40;
1812 		else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
1813 			bw = BW_80;
1814 		else
1815 			bw = BW_20;
1816 
1817 		mi->supported[i] = minstrel_get_valid_vht_rates(bw, nss,
1818 				vht_cap->vht_mcs.tx_mcs_map);
1819 
1820 		if (mi->supported[i])
1821 			n_supported++;
1822 	}
1823 
1824 	sta_info = container_of(sta, struct sta_info, sta);
1825 	mi->use_short_preamble = test_sta_flag(sta_info, WLAN_STA_SHORT_PREAMBLE) &&
1826 				 sta_info->sdata->vif.bss_conf.use_short_preamble;
1827 
1828 	minstrel_ht_update_cck(mp, mi, sband, sta);
1829 	minstrel_ht_update_ofdm(mp, mi, sband, sta);
1830 
1831 	/* create an initial rate table with the lowest supported rates */
1832 	minstrel_ht_update_stats(mp, mi);
1833 	minstrel_ht_update_rates(mp, mi);
1834 }
1835 
1836 static void
minstrel_ht_rate_init(void * priv,struct ieee80211_supported_band * sband,struct cfg80211_chan_def * chandef,struct ieee80211_sta * sta,void * priv_sta)1837 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
1838 		      struct cfg80211_chan_def *chandef,
1839                       struct ieee80211_sta *sta, void *priv_sta)
1840 {
1841 	minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1842 }
1843 
1844 static void
minstrel_ht_rate_update(void * priv,struct ieee80211_supported_band * sband,struct cfg80211_chan_def * chandef,struct ieee80211_sta * sta,void * priv_sta,u32 changed)1845 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
1846 			struct cfg80211_chan_def *chandef,
1847                         struct ieee80211_sta *sta, void *priv_sta,
1848                         u32 changed)
1849 {
1850 	minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1851 }
1852 
1853 static void *
minstrel_ht_alloc_sta(void * priv,struct ieee80211_sta * sta,gfp_t gfp)1854 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
1855 {
1856 	struct ieee80211_supported_band *sband;
1857 	struct minstrel_ht_sta *mi;
1858 	struct minstrel_priv *mp = priv;
1859 	struct ieee80211_hw *hw = mp->hw;
1860 	int max_rates = 0;
1861 	int i;
1862 
1863 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1864 		sband = hw->wiphy->bands[i];
1865 		if (sband && sband->n_bitrates > max_rates)
1866 			max_rates = sband->n_bitrates;
1867 	}
1868 
1869 	return kzalloc(sizeof(*mi), gfp);
1870 }
1871 
1872 static void
minstrel_ht_free_sta(void * priv,struct ieee80211_sta * sta,void * priv_sta)1873 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1874 {
1875 	kfree(priv_sta);
1876 }
1877 
1878 static void
minstrel_ht_fill_rate_array(u8 * dest,struct ieee80211_supported_band * sband,const s16 * bitrates,int n_rates,u32 rate_flags)1879 minstrel_ht_fill_rate_array(u8 *dest, struct ieee80211_supported_band *sband,
1880 			    const s16 *bitrates, int n_rates, u32 rate_flags)
1881 {
1882 	int i, j;
1883 
1884 	for (i = 0; i < sband->n_bitrates; i++) {
1885 		struct ieee80211_rate *rate = &sband->bitrates[i];
1886 
1887 		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
1888 			continue;
1889 
1890 		for (j = 0; j < n_rates; j++) {
1891 			if (rate->bitrate != bitrates[j])
1892 				continue;
1893 
1894 			dest[j] = i;
1895 			break;
1896 		}
1897 	}
1898 }
1899 
1900 static void
minstrel_ht_init_cck_rates(struct minstrel_priv * mp)1901 minstrel_ht_init_cck_rates(struct minstrel_priv *mp)
1902 {
1903 	static const s16 bitrates[4] = { 10, 20, 55, 110 };
1904 	struct ieee80211_supported_band *sband;
1905 	u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
1906 
1907 	memset(mp->cck_rates, 0xff, sizeof(mp->cck_rates));
1908 	sband = mp->hw->wiphy->bands[NL80211_BAND_2GHZ];
1909 	if (!sband)
1910 		return;
1911 
1912 	BUILD_BUG_ON(ARRAY_SIZE(mp->cck_rates) != ARRAY_SIZE(bitrates));
1913 	minstrel_ht_fill_rate_array(mp->cck_rates, sband,
1914 				    minstrel_cck_bitrates,
1915 				    ARRAY_SIZE(minstrel_cck_bitrates),
1916 				    rate_flags);
1917 }
1918 
1919 static void
minstrel_ht_init_ofdm_rates(struct minstrel_priv * mp,enum nl80211_band band)1920 minstrel_ht_init_ofdm_rates(struct minstrel_priv *mp, enum nl80211_band band)
1921 {
1922 	static const s16 bitrates[8] = { 60, 90, 120, 180, 240, 360, 480, 540 };
1923 	struct ieee80211_supported_band *sband;
1924 	u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
1925 
1926 	memset(mp->ofdm_rates[band], 0xff, sizeof(mp->ofdm_rates[band]));
1927 	sband = mp->hw->wiphy->bands[band];
1928 	if (!sband)
1929 		return;
1930 
1931 	BUILD_BUG_ON(ARRAY_SIZE(mp->ofdm_rates[band]) != ARRAY_SIZE(bitrates));
1932 	minstrel_ht_fill_rate_array(mp->ofdm_rates[band], sband,
1933 				    minstrel_ofdm_bitrates,
1934 				    ARRAY_SIZE(minstrel_ofdm_bitrates),
1935 				    rate_flags);
1936 }
1937 
1938 static void *
minstrel_ht_alloc(struct ieee80211_hw * hw)1939 minstrel_ht_alloc(struct ieee80211_hw *hw)
1940 {
1941 	struct minstrel_priv *mp;
1942 	int i;
1943 
1944 	mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
1945 	if (!mp)
1946 		return NULL;
1947 
1948 	/* contention window settings
1949 	 * Just an approximation. Using the per-queue values would complicate
1950 	 * the calculations and is probably unnecessary */
1951 	mp->cw_min = 15;
1952 	mp->cw_max = 1023;
1953 
1954 	/* maximum time that the hw is allowed to stay in one MRR segment */
1955 	mp->segment_size = 6000;
1956 
1957 	if (hw->max_rate_tries > 0)
1958 		mp->max_retry = hw->max_rate_tries;
1959 	else
1960 		/* safe default, does not necessarily have to match hw properties */
1961 		mp->max_retry = 7;
1962 
1963 	if (hw->max_rates >= 4)
1964 		mp->has_mrr = true;
1965 
1966 	mp->hw = hw;
1967 	mp->update_interval = HZ / 20;
1968 
1969 	minstrel_ht_init_cck_rates(mp);
1970 	for (i = 0; i < ARRAY_SIZE(mp->hw->wiphy->bands); i++)
1971 	    minstrel_ht_init_ofdm_rates(mp, i);
1972 
1973 	return mp;
1974 }
1975 
1976 #ifdef CONFIG_MAC80211_DEBUGFS
minstrel_ht_add_debugfs(struct ieee80211_hw * hw,void * priv,struct dentry * debugfsdir)1977 static void minstrel_ht_add_debugfs(struct ieee80211_hw *hw, void *priv,
1978 				    struct dentry *debugfsdir)
1979 {
1980 	struct minstrel_priv *mp = priv;
1981 
1982 	mp->fixed_rate_idx = (u32) -1;
1983 	debugfs_create_u32("fixed_rate_idx", S_IRUGO | S_IWUGO, debugfsdir,
1984 			   &mp->fixed_rate_idx);
1985 }
1986 #endif
1987 
1988 static void
minstrel_ht_free(void * priv)1989 minstrel_ht_free(void *priv)
1990 {
1991 	kfree(priv);
1992 }
1993 
minstrel_ht_get_expected_throughput(void * priv_sta)1994 static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1995 {
1996 	struct minstrel_ht_sta *mi = priv_sta;
1997 	int i, j, prob, tp_avg;
1998 
1999 	i = MI_RATE_GROUP(mi->max_tp_rate[0]);
2000 	j = MI_RATE_IDX(mi->max_tp_rate[0]);
2001 	prob = mi->groups[i].rates[j].prob_avg;
2002 
2003 	/* convert tp_avg from pkt per second in kbps */
2004 	tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * 10;
2005 	tp_avg = tp_avg * AVG_PKT_SIZE * 8 / 1024;
2006 
2007 	return tp_avg;
2008 }
2009 
2010 static const struct rate_control_ops mac80211_minstrel_ht = {
2011 	.name = "minstrel_ht",
2012 	.capa = RATE_CTRL_CAPA_AMPDU_TRIGGER,
2013 	.tx_status_ext = minstrel_ht_tx_status,
2014 	.get_rate = minstrel_ht_get_rate,
2015 	.rate_init = minstrel_ht_rate_init,
2016 	.rate_update = minstrel_ht_rate_update,
2017 	.alloc_sta = minstrel_ht_alloc_sta,
2018 	.free_sta = minstrel_ht_free_sta,
2019 	.alloc = minstrel_ht_alloc,
2020 	.free = minstrel_ht_free,
2021 #ifdef CONFIG_MAC80211_DEBUGFS
2022 	.add_debugfs = minstrel_ht_add_debugfs,
2023 	.add_sta_debugfs = minstrel_ht_add_sta_debugfs,
2024 #endif
2025 	.get_expected_throughput = minstrel_ht_get_expected_throughput,
2026 };
2027 
2028 
init_sample_table(void)2029 static void __init init_sample_table(void)
2030 {
2031 	int col, i, new_idx;
2032 	u8 rnd[MCS_GROUP_RATES];
2033 
2034 	memset(sample_table, 0xff, sizeof(sample_table));
2035 	for (col = 0; col < SAMPLE_COLUMNS; col++) {
2036 		prandom_bytes(rnd, sizeof(rnd));
2037 		for (i = 0; i < MCS_GROUP_RATES; i++) {
2038 			new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
2039 			while (sample_table[col][new_idx] != 0xff)
2040 				new_idx = (new_idx + 1) % MCS_GROUP_RATES;
2041 
2042 			sample_table[col][new_idx] = i;
2043 		}
2044 	}
2045 }
2046 
2047 int __init
rc80211_minstrel_init(void)2048 rc80211_minstrel_init(void)
2049 {
2050 	init_sample_table();
2051 	return ieee80211_rate_control_register(&mac80211_minstrel_ht);
2052 }
2053 
2054 void
rc80211_minstrel_exit(void)2055 rc80211_minstrel_exit(void)
2056 {
2057 	ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
2058 }
2059