root/drivers/net/wireless/ath/ath9k/dynack.c

DEFINITIONS

1. ath_dynack_get_max_to
2. ath_dynack_ewma
3. ath_dynack_get_sifs
4. ath_dynack_bssidmask
5. ath_dynack_set_timeout
6. ath_dynack_compute_ackto
7. ath_dynack_compute_to
8. ath_dynack_sample_tx_ts
9. ath_dynack_sample_ack_ts
10. ath_dynack_node_init
11. ath_dynack_node_deinit
12. ath_dynack_reset
13. ath_dynack_init

   1 /*
   2  * Copyright (c) 2014, Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16 
  17 #include "ath9k.h"
  18 #include "hw.h"
  19 #include "dynack.h"
  20 
  21 #define COMPUTE_TO              (5 * HZ)
  22 #define LATEACK_DELAY           (10 * HZ)
  23 #define EWMA_LEVEL              96
  24 #define EWMA_DIV                128
  25 
  26 /**
  27  * ath_dynack_get_max_to - set max timeout according to channel width
  28  * @ah: ath hw
  29  *
  30  */
  31 static u32 ath_dynack_get_max_to(struct ath_hw *ah)
  32 {
  33         const struct ath9k_channel *chan = ah->curchan;
  34 
  35         if (!chan)
  36                 return 300;
  37 
  38         if (IS_CHAN_HT40(chan))
  39                 return 300;
  40         if (IS_CHAN_HALF_RATE(chan))
  41                 return 750;
  42         if (IS_CHAN_QUARTER_RATE(chan))
  43                 return 1500;
  44         return 600;
  45 }
  46 
  47 /**
  48  * ath_dynack_ewma - EWMA (Exponentially Weighted Moving Average) calculation
  49  *
  50  */
  51 static inline int ath_dynack_ewma(int old, int new)
  52 {
  53         if (old > 0)
  54                 return (new * (EWMA_DIV - EWMA_LEVEL) +
  55                         old * EWMA_LEVEL) / EWMA_DIV;
  56         else
  57                 return new;
  58 }
  59 
  60 /**
  61  * ath_dynack_get_sifs - get sifs time based on phy used
  62  * @ah: ath hw
  63  * @phy: phy used
  64  *
  65  */
  66 static inline u32 ath_dynack_get_sifs(struct ath_hw *ah, int phy)
  67 {
  68         u32 sifs = CCK_SIFS_TIME;
  69 
  70         if (phy == WLAN_RC_PHY_OFDM) {
  71                 if (IS_CHAN_QUARTER_RATE(ah->curchan))
  72                         sifs = OFDM_SIFS_TIME_QUARTER;
  73                 else if (IS_CHAN_HALF_RATE(ah->curchan))
  74                         sifs = OFDM_SIFS_TIME_HALF;
  75                 else
  76                         sifs = OFDM_SIFS_TIME;
  77         }
  78         return sifs;
  79 }
  80 
  81 /**
  82  * ath_dynack_bssidmask - filter out ACK frames based on BSSID mask
  83  * @ah: ath hw
  84  * @mac: receiver address
  85  */
  86 static inline bool ath_dynack_bssidmask(struct ath_hw *ah, const u8 *mac)
  87 {
  88         int i;
  89         struct ath_common *common = ath9k_hw_common(ah);
  90 
  91         for (i = 0; i < ETH_ALEN; i++) {
  92                 if ((common->macaddr[i] & common->bssidmask[i]) !=
  93                     (mac[i] & common->bssidmask[i]))
  94                         return false;
  95         }
  96 
  97         return true;
  98 }
  99 
 100 /**
 101  * ath_dynack_set_timeout - configure timeouts/slottime registers
 102  * @ah: ath hw
 103  * @to: timeout value
 104  *
 105  */
 106 static void ath_dynack_set_timeout(struct ath_hw *ah, int to)
 107 {
 108         struct ath_common *common = ath9k_hw_common(ah);
 109         int slottime = (to - 3) / 2;
 110 
 111         ath_dbg(common, DYNACK, "ACK timeout %u slottime %u\n",
 112                 to, slottime);
 113         ath9k_hw_setslottime(ah, slottime);
 114         ath9k_hw_set_ack_timeout(ah, to);
 115         ath9k_hw_set_cts_timeout(ah, to);
 116 }
 117 
 118 /**
 119  * ath_dynack_compute_ackto - compute ACK timeout as the maximum STA timeout
 120  * @ah: ath hw
 121  *
 122  * should be called while holding qlock
 123  */
 124 static void ath_dynack_compute_ackto(struct ath_hw *ah)
 125 {
 126         struct ath_dynack *da = &ah->dynack;
 127         struct ath_node *an;
 128         int to = 0;
 129 
 130         list_for_each_entry(an, &da->nodes, list)
 131                 if (an->ackto > to)
 132                         to = an->ackto;
 133 
 134         if (to && da->ackto != to) {
 135                 ath_dynack_set_timeout(ah, to);
 136                 da->ackto = to;
 137         }
 138 }
 139 
 140 /**
 141  * ath_dynack_compute_to - compute STA ACK timeout
 142  * @ah: ath hw
 143  *
 144  * should be called while holding qlock
 145  */
 146 static void ath_dynack_compute_to(struct ath_hw *ah)
 147 {
 148         struct ath_dynack *da = &ah->dynack;
 149         u32 ackto, ack_ts, max_to;
 150         struct ieee80211_sta *sta;
 151         struct ts_info *st_ts;
 152         struct ath_node *an;
 153         u8 *dst, *src;
 154 
 155         rcu_read_lock();
 156 
 157         max_to = ath_dynack_get_max_to(ah);
 158         while (da->st_rbf.h_rb != da->st_rbf.t_rb &&
 159                da->ack_rbf.h_rb != da->ack_rbf.t_rb) {
 160                 ack_ts = da->ack_rbf.tstamp[da->ack_rbf.h_rb];
 161                 st_ts = &da->st_rbf.ts[da->st_rbf.h_rb];
 162                 dst = da->st_rbf.addr[da->st_rbf.h_rb].h_dest;
 163                 src = da->st_rbf.addr[da->st_rbf.h_rb].h_src;
 164 
 165                 ath_dbg(ath9k_hw_common(ah), DYNACK,
 166                         "ack_ts %u st_ts %u st_dur %u [%u-%u]\n",
 167                         ack_ts, st_ts->tstamp, st_ts->dur,
 168                         da->ack_rbf.h_rb, da->st_rbf.h_rb);
 169 
 170                 if (ack_ts > st_ts->tstamp + st_ts->dur) {
 171                         ackto = ack_ts - st_ts->tstamp - st_ts->dur;
 172 
 173                         if (ackto < max_to) {
 174                                 sta = ieee80211_find_sta_by_ifaddr(ah->hw, dst,
 175                                                                    src);
 176                                 if (sta) {
 177                                         an = (struct ath_node *)sta->drv_priv;
 178                                         an->ackto = ath_dynack_ewma(an->ackto,
 179                                                                     ackto);
 180                                         ath_dbg(ath9k_hw_common(ah), DYNACK,
 181                                                 "%pM to %d [%u]\n", dst,
 182                                                 an->ackto, ackto);
 183                                         if (time_is_before_jiffies(da->lto)) {
 184                                                 ath_dynack_compute_ackto(ah);
 185                                                 da->lto = jiffies + COMPUTE_TO;
 186                                         }
 187                                 }
 188                                 INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
 189                         }
 190                         INCR(da->st_rbf.h_rb, ATH_DYN_BUF);
 191                 } else {
 192                         INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
 193                 }
 194         }
 195 
 196         rcu_read_unlock();
 197 }
 198 
 199 /**
 200  * ath_dynack_sample_tx_ts - status timestamp sampling method
 201  * @ah: ath hw
 202  * @skb: socket buffer
 203  * @ts: tx status info
 204  * @sta: station pointer
 205  *
 206  */
 207 void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
 208                              struct ath_tx_status *ts,
 209                              struct ieee80211_sta *sta)
 210 {
 211         struct ieee80211_hdr *hdr;
 212         struct ath_dynack *da = &ah->dynack;
 213         struct ath_common *common = ath9k_hw_common(ah);
 214         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 215         u32 dur = ts->duration;
 216         u8 ridx;
 217 
 218         if (!da->enabled || (info->flags & IEEE80211_TX_CTL_NO_ACK))
 219                 return;
 220 
 221         spin_lock_bh(&da->qlock);
 222 
 223         hdr = (struct ieee80211_hdr *)skb->data;
 224 
 225         /* late ACK */
 226         if (ts->ts_status & ATH9K_TXERR_XRETRY) {
 227                 if (ieee80211_is_assoc_req(hdr->frame_control) ||
 228                     ieee80211_is_assoc_resp(hdr->frame_control) ||
 229                     ieee80211_is_auth(hdr->frame_control)) {
 230                         u32 max_to = ath_dynack_get_max_to(ah);
 231 
 232                         ath_dbg(common, DYNACK, "late ack\n");
 233                         ath_dynack_set_timeout(ah, max_to);
 234                         if (sta) {
 235                                 struct ath_node *an;
 236 
 237                                 an = (struct ath_node *)sta->drv_priv;
 238                                 an->ackto = -1;
 239                         }
 240                         da->lto = jiffies + LATEACK_DELAY;
 241                 }
 242 
 243                 spin_unlock_bh(&da->qlock);
 244                 return;
 245         }
 246 
 247         ridx = ts->ts_rateindex;
 248 
 249         da->st_rbf.ts[da->st_rbf.t_rb].tstamp = ts->ts_tstamp;
 250         ether_addr_copy(da->st_rbf.addr[da->st_rbf.t_rb].h_dest, hdr->addr1);
 251         ether_addr_copy(da->st_rbf.addr[da->st_rbf.t_rb].h_src, hdr->addr2);
 252 
 253         if (!(info->status.rates[ridx].flags & IEEE80211_TX_RC_MCS)) {
 254                 const struct ieee80211_rate *rate;
 255                 struct ieee80211_tx_rate *rates = info->status.rates;
 256                 u32 phy;
 257 
 258                 rate = &common->sbands[info->band].bitrates[rates[ridx].idx];
 259                 if (info->band == NL80211_BAND_2GHZ &&
 260                     !(rate->flags & IEEE80211_RATE_ERP_G))
 261                         phy = WLAN_RC_PHY_CCK;
 262                 else
 263                         phy = WLAN_RC_PHY_OFDM;
 264 
 265                 dur -= ath_dynack_get_sifs(ah, phy);
 266         }
 267         da->st_rbf.ts[da->st_rbf.t_rb].dur = dur;
 268 
 269         INCR(da->st_rbf.t_rb, ATH_DYN_BUF);
 270         if (da->st_rbf.t_rb == da->st_rbf.h_rb)
 271                 INCR(da->st_rbf.h_rb, ATH_DYN_BUF);
 272 
 273         ath_dbg(common, DYNACK, "{%pM} tx sample %u [dur %u][h %u-t %u]\n",
 274                 hdr->addr1, ts->ts_tstamp, dur, da->st_rbf.h_rb,
 275                 da->st_rbf.t_rb);
 276 
 277         ath_dynack_compute_to(ah);
 278 
 279         spin_unlock_bh(&da->qlock);
 280 }
 281 EXPORT_SYMBOL(ath_dynack_sample_tx_ts);
 282 
 283 /**
 284  * ath_dynack_sample_ack_ts - ACK timestamp sampling method
 285  * @ah: ath hw
 286  * @skb: socket buffer
 287  * @ts: rx timestamp
 288  *
 289  */
 290 void ath_dynack_sample_ack_ts(struct ath_hw *ah, struct sk_buff *skb,
 291                               u32 ts)
 292 {
 293         struct ath_dynack *da = &ah->dynack;
 294         struct ath_common *common = ath9k_hw_common(ah);
 295         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 296 
 297         if (!da->enabled || !ath_dynack_bssidmask(ah, hdr->addr1))
 298                 return;
 299 
 300         spin_lock_bh(&da->qlock);
 301         da->ack_rbf.tstamp[da->ack_rbf.t_rb] = ts;
 302 
 303         INCR(da->ack_rbf.t_rb, ATH_DYN_BUF);
 304         if (da->ack_rbf.t_rb == da->ack_rbf.h_rb)
 305                 INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
 306 
 307         ath_dbg(common, DYNACK, "rx sample %u [h %u-t %u]\n",
 308                 ts, da->ack_rbf.h_rb, da->ack_rbf.t_rb);
 309 
 310         ath_dynack_compute_to(ah);
 311 
 312         spin_unlock_bh(&da->qlock);
 313 }
 314 EXPORT_SYMBOL(ath_dynack_sample_ack_ts);
 315 
 316 /**
 317  * ath_dynack_node_init - init ath_node related info
 318  * @ah: ath hw
 319  * @an: ath node
 320  *
 321  */
 322 void ath_dynack_node_init(struct ath_hw *ah, struct ath_node *an)
 323 {
 324         struct ath_dynack *da = &ah->dynack;
 325 
 326         an->ackto = da->ackto;
 327 
 328         spin_lock_bh(&da->qlock);
 329         list_add_tail(&an->list, &da->nodes);
 330         spin_unlock_bh(&da->qlock);
 331 }
 332 EXPORT_SYMBOL(ath_dynack_node_init);
 333 
 334 /**
 335  * ath_dynack_node_deinit - deinit ath_node related info
 336  * @ah: ath hw
 337  * @an: ath node
 338  *
 339  */
 340 void ath_dynack_node_deinit(struct ath_hw *ah, struct ath_node *an)
 341 {
 342         struct ath_dynack *da = &ah->dynack;
 343 
 344         spin_lock_bh(&da->qlock);
 345         list_del(&an->list);
 346         spin_unlock_bh(&da->qlock);
 347 }
 348 EXPORT_SYMBOL(ath_dynack_node_deinit);
 349 
 350 /**
 351  * ath_dynack_reset - reset dynack processing
 352  * @ah: ath hw
 353  *
 354  */
 355 void ath_dynack_reset(struct ath_hw *ah)
 356 {
 357         struct ath_dynack *da = &ah->dynack;
 358         struct ath_node *an;
 359 
 360         spin_lock_bh(&da->qlock);
 361 
 362         da->lto = jiffies + COMPUTE_TO;
 363 
 364         da->st_rbf.t_rb = 0;
 365         da->st_rbf.h_rb = 0;
 366         da->ack_rbf.t_rb = 0;
 367         da->ack_rbf.h_rb = 0;
 368 
 369         da->ackto = ath_dynack_get_max_to(ah);
 370         list_for_each_entry(an, &da->nodes, list)
 371                 an->ackto = da->ackto;
 372 
 373         /* init acktimeout */
 374         ath_dynack_set_timeout(ah, da->ackto);
 375 
 376         spin_unlock_bh(&da->qlock);
 377 }
 378 EXPORT_SYMBOL(ath_dynack_reset);
 379 
 380 /**
 381  * ath_dynack_init - init dynack data structure
 382  * @ah: ath hw
 383  *
 384  */
 385 void ath_dynack_init(struct ath_hw *ah)
 386 {
 387         struct ath_dynack *da = &ah->dynack;
 388 
 389         memset(da, 0, sizeof(struct ath_dynack));
 390 
 391         spin_lock_init(&da->qlock);
 392         INIT_LIST_HEAD(&da->nodes);
 393         /* ackto = slottime + sifs + air delay */
 394         da->ackto = 9 + 16 + 64;
 395 
 396         ah->hw->wiphy->features |= NL80211_FEATURE_ACKTO_ESTIMATION;
 397 }