LXR linux/drivers/net/wireless/ath/ath9k/dynack.c

   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 LATEACK_TO              256
  24#define MAX_DELAY               300
  25#define EWMA_LEVEL              96
  26#define EWMA_DIV                128
  27
  28/**
  29 * ath_dynack_ewma - EWMA (Exponentially Weighted Moving Average) calculation
  30 *
  31 */
  32static inline u32 ath_dynack_ewma(u32 old, u32 new)
  33{
  34        return (new * (EWMA_DIV - EWMA_LEVEL) + old * EWMA_LEVEL) / EWMA_DIV;
  35}
  36
  37/**
  38 * ath_dynack_get_sifs - get sifs time based on phy used
  39 * @ah: ath hw
  40 * @phy: phy used
  41 *
  42 */
  43static inline u32 ath_dynack_get_sifs(struct ath_hw *ah, int phy)
  44{
  45        u32 sifs = CCK_SIFS_TIME;
  46
  47        if (phy == WLAN_RC_PHY_OFDM) {
  48                if (IS_CHAN_QUARTER_RATE(ah->curchan))
  49                        sifs = OFDM_SIFS_TIME_QUARTER;
  50                else if (IS_CHAN_HALF_RATE(ah->curchan))
  51                        sifs = OFDM_SIFS_TIME_HALF;
  52                else
  53                        sifs = OFDM_SIFS_TIME;
  54        }
  55        return sifs;
  56}
  57
  58/**
  59 * ath_dynack_bssidmask - filter out ACK frames based on BSSID mask
  60 * @ah: ath hw
  61 * @mac: receiver address
  62 */
  63static inline bool ath_dynack_bssidmask(struct ath_hw *ah, const u8 *mac)
  64{
  65        int i;
  66        struct ath_common *common = ath9k_hw_common(ah);
  67
  68        for (i = 0; i < ETH_ALEN; i++) {
  69                if ((common->macaddr[i] & common->bssidmask[i]) !=
  70                    (mac[i] & common->bssidmask[i]))
  71                        return false;
  72        }
  73
  74        return true;
  75}
  76
  77/**
  78 * ath_dynack_compute_ackto - compute ACK timeout as the maximum STA timeout
  79 * @ah: ath hw
  80 *
  81 * should be called while holding qlock
  82 */
  83static void ath_dynack_compute_ackto(struct ath_hw *ah)
  84{
  85        struct ath_node *an;
  86        u32 to = 0;
  87        struct ath_dynack *da = &ah->dynack;
  88        struct ath_common *common = ath9k_hw_common(ah);
  89
  90        list_for_each_entry(an, &da->nodes, list)
  91                if (an->ackto > to)
  92                        to = an->ackto;
  93
  94        if (to && da->ackto != to) {
  95                u32 slottime;
  96
  97                slottime = (to - 3) / 2;
  98                da->ackto = to;
  99                ath_dbg(common, DYNACK, "ACK timeout %u slottime %u\n",
 100                        da->ackto, slottime);
 101                ath9k_hw_setslottime(ah, slottime);
 102                ath9k_hw_set_ack_timeout(ah, da->ackto);
 103                ath9k_hw_set_cts_timeout(ah, da->ackto);
 104        }
 105}
 106
 107/**
 108 * ath_dynack_compute_to - compute STA ACK timeout
 109 * @ah: ath hw
 110 *
 111 * should be called while holding qlock
 112 */
 113static void ath_dynack_compute_to(struct ath_hw *ah)
 114{
 115        u32 ackto, ack_ts;
 116        u8 *dst, *src;
 117        struct ieee80211_sta *sta;
 118        struct ath_node *an;
 119        struct ts_info *st_ts;
 120        struct ath_dynack *da = &ah->dynack;
 121
 122        rcu_read_lock();
 123
 124        while (da->st_rbf.h_rb != da->st_rbf.t_rb &&
 125               da->ack_rbf.h_rb != da->ack_rbf.t_rb) {
 126                ack_ts = da->ack_rbf.tstamp[da->ack_rbf.h_rb];
 127                st_ts = &da->st_rbf.ts[da->st_rbf.h_rb];
 128                dst = da->st_rbf.addr[da->st_rbf.h_rb].h_dest;
 129                src = da->st_rbf.addr[da->st_rbf.h_rb].h_src;
 130
 131                ath_dbg(ath9k_hw_common(ah), DYNACK,
 132                        "ack_ts %u st_ts %u st_dur %u [%u-%u]\n",
 133                        ack_ts, st_ts->tstamp, st_ts->dur,
 134                        da->ack_rbf.h_rb, da->st_rbf.h_rb);
 135
 136                if (ack_ts > st_ts->tstamp + st_ts->dur) {
 137                        ackto = ack_ts - st_ts->tstamp - st_ts->dur;
 138
 139                        if (ackto < MAX_DELAY) {
 140                                sta = ieee80211_find_sta_by_ifaddr(ah->hw, dst,
 141                                                                   src);
 142                                if (sta) {
 143                                        an = (struct ath_node *)sta->drv_priv;
 144                                        an->ackto = ath_dynack_ewma(an->ackto,
 145                                                                    ackto);
 146                                        ath_dbg(ath9k_hw_common(ah), DYNACK,
 147                                                "%pM to %u\n", dst, an->ackto);
 148                                        if (time_is_before_jiffies(da->lto)) {
 149                                                ath_dynack_compute_ackto(ah);
 150                                                da->lto = jiffies + COMPUTE_TO;
 151                                        }
 152                                }
 153                                INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
 154                        }
 155                        INCR(da->st_rbf.h_rb, ATH_DYN_BUF);
 156                } else {
 157                        INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
 158                }
 159        }
 160
 161        rcu_read_unlock();
 162}
 163
 164/**
 165 * ath_dynack_sample_tx_ts - status timestamp sampling method
 166 * @ah: ath hw
 167 * @skb: socket buffer
 168 * @ts: tx status info
 169 *
 170 */
 171void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
 172                             struct ath_tx_status *ts)
 173{
 174        u8 ridx;
 175        struct ieee80211_hdr *hdr;
 176        struct ath_dynack *da = &ah->dynack;
 177        struct ath_common *common = ath9k_hw_common(ah);
 178        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 179
 180        if ((info->flags & IEEE80211_TX_CTL_NO_ACK) || !da->enabled)
 181                return;
 182
 183        spin_lock_bh(&da->qlock);
 184
 185        hdr = (struct ieee80211_hdr *)skb->data;
 186
 187        /* late ACK */
 188        if (ts->ts_status & ATH9K_TXERR_XRETRY) {
 189                if (ieee80211_is_assoc_req(hdr->frame_control) ||
 190                    ieee80211_is_assoc_resp(hdr->frame_control)) {
 191                        ath_dbg(common, DYNACK, "late ack\n");
 192                        ath9k_hw_setslottime(ah, (LATEACK_TO - 3) / 2);
 193                        ath9k_hw_set_ack_timeout(ah, LATEACK_TO);
 194                        ath9k_hw_set_cts_timeout(ah, LATEACK_TO);
 195                        da->lto = jiffies + LATEACK_DELAY;
 196                }
 197
 198                spin_unlock_bh(&da->qlock);
 199                return;
 200        }
 201
 202        ridx = ts->ts_rateindex;
 203
 204        da->st_rbf.ts[da->st_rbf.t_rb].tstamp = ts->ts_tstamp;
 205        da->st_rbf.ts[da->st_rbf.t_rb].dur = ts->duration;
 206        ether_addr_copy(da->st_rbf.addr[da->st_rbf.t_rb].h_dest, hdr->addr1);
 207        ether_addr_copy(da->st_rbf.addr[da->st_rbf.t_rb].h_src, hdr->addr2);
 208
 209        if (!(info->status.rates[ridx].flags & IEEE80211_TX_RC_MCS)) {
 210                u32 phy, sifs;
 211                const struct ieee80211_rate *rate;
 212                struct ieee80211_tx_rate *rates = info->status.rates;
 213
 214                rate = &common->sbands[info->band].bitrates[rates[ridx].idx];
 215                if (info->band == NL80211_BAND_2GHZ &&
 216                    !(rate->flags & IEEE80211_RATE_ERP_G))
 217                        phy = WLAN_RC_PHY_CCK;
 218                else
 219                        phy = WLAN_RC_PHY_OFDM;
 220
 221                sifs = ath_dynack_get_sifs(ah, phy);
 222                da->st_rbf.ts[da->st_rbf.t_rb].dur -= sifs;
 223        }
 224
 225        ath_dbg(common, DYNACK, "{%pM} tx sample %u [dur %u][h %u-t %u]\n",
 226                hdr->addr1, da->st_rbf.ts[da->st_rbf.t_rb].tstamp,
 227                da->st_rbf.ts[da->st_rbf.t_rb].dur, da->st_rbf.h_rb,
 228                (da->st_rbf.t_rb + 1) % ATH_DYN_BUF);
 229
 230        INCR(da->st_rbf.t_rb, ATH_DYN_BUF);
 231        if (da->st_rbf.t_rb == da->st_rbf.h_rb)
 232                INCR(da->st_rbf.h_rb, ATH_DYN_BUF);
 233
 234        ath_dynack_compute_to(ah);
 235
 236        spin_unlock_bh(&da->qlock);
 237}
 238EXPORT_SYMBOL(ath_dynack_sample_tx_ts);
 239
 240/**
 241 * ath_dynack_sample_ack_ts - ACK timestamp sampling method
 242 * @ah: ath hw
 243 * @skb: socket buffer
 244 * @ts: rx timestamp
 245 *
 246 */
 247void ath_dynack_sample_ack_ts(struct ath_hw *ah, struct sk_buff *skb,
 248                              u32 ts)
 249{
 250        struct ath_dynack *da = &ah->dynack;
 251        struct ath_common *common = ath9k_hw_common(ah);
 252        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 253
 254        if (!ath_dynack_bssidmask(ah, hdr->addr1) || !da->enabled)
 255                return;
 256
 257        spin_lock_bh(&da->qlock);
 258        da->ack_rbf.tstamp[da->ack_rbf.t_rb] = ts;
 259
 260        ath_dbg(common, DYNACK, "rx sample %u [h %u-t %u]\n",
 261                da->ack_rbf.tstamp[da->ack_rbf.t_rb],
 262                da->ack_rbf.h_rb, (da->ack_rbf.t_rb + 1) % ATH_DYN_BUF);
 263
 264        INCR(da->ack_rbf.t_rb, ATH_DYN_BUF);
 265        if (da->ack_rbf.t_rb == da->ack_rbf.h_rb)
 266                INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
 267
 268        ath_dynack_compute_to(ah);
 269
 270        spin_unlock_bh(&da->qlock);
 271}
 272EXPORT_SYMBOL(ath_dynack_sample_ack_ts);
 273
 274/**
 275 * ath_dynack_node_init - init ath_node related info
 276 * @ah: ath hw
 277 * @an: ath node
 278 *
 279 */
 280void ath_dynack_node_init(struct ath_hw *ah, struct ath_node *an)
 281{
 282        /* ackto = slottime + sifs + air delay */
 283        u32 ackto = 9 + 16 + 64;
 284        struct ath_dynack *da = &ah->dynack;
 285
 286        an->ackto = ackto;
 287
 288        spin_lock(&da->qlock);
 289        list_add_tail(&an->list, &da->nodes);
 290        spin_unlock(&da->qlock);
 291}
 292EXPORT_SYMBOL(ath_dynack_node_init);
 293
 294/**
 295 * ath_dynack_node_deinit - deinit ath_node related info
 296 * @ah: ath hw
 297 * @an: ath node
 298 *
 299 */
 300void ath_dynack_node_deinit(struct ath_hw *ah, struct ath_node *an)
 301{
 302        struct ath_dynack *da = &ah->dynack;
 303
 304        spin_lock(&da->qlock);
 305        list_del(&an->list);
 306        spin_unlock(&da->qlock);
 307}
 308EXPORT_SYMBOL(ath_dynack_node_deinit);
 309
 310/**
 311 * ath_dynack_reset - reset dynack processing
 312 * @ah: ath hw
 313 *
 314 */
 315void ath_dynack_reset(struct ath_hw *ah)
 316{
 317        /* ackto = slottime + sifs + air delay */
 318        u32 ackto = 9 + 16 + 64;
 319        struct ath_dynack *da = &ah->dynack;
 320
 321        da->lto = jiffies;
 322        da->ackto = ackto;
 323
 324        da->st_rbf.t_rb = 0;
 325        da->st_rbf.h_rb = 0;
 326        da->ack_rbf.t_rb = 0;
 327        da->ack_rbf.h_rb = 0;
 328
 329        /* init acktimeout */
 330        ath9k_hw_setslottime(ah, (ackto - 3) / 2);
 331        ath9k_hw_set_ack_timeout(ah, ackto);
 332        ath9k_hw_set_cts_timeout(ah, ackto);
 333}
 334EXPORT_SYMBOL(ath_dynack_reset);
 335
 336/**
 337 * ath_dynack_init - init dynack data structure
 338 * @ah: ath hw
 339 *
 340 */
 341void ath_dynack_init(struct ath_hw *ah)
 342{
 343        struct ath_dynack *da = &ah->dynack;
 344
 345        memset(da, 0, sizeof(struct ath_dynack));
 346
 347        spin_lock_init(&da->qlock);
 348        INIT_LIST_HEAD(&da->nodes);
 349
 350        ah->hw->wiphy->features |= NL80211_FEATURE_ACKTO_ESTIMATION;
 351}
 352