drivers/staging/brcm80211/brcmsmac/wlc_stf.c

   1 /*
   2  * Copyright (c) 2010 Broadcom Corporation
   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 ANY
  11  * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
  13  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  14  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19
  20 #include <proto/802.11.h>
  21
  22 #include <bcmdefs.h>
  23 #include <bcmutils.h>
  24 #include <aiutils.h>
  25 #include <wlioctl.h>
  26 #include <bcmwifi.h>
  27 #include <sbhnddma.h>
  28
  29 #include "wlc_types.h"
  30 #include "d11.h"
  31 #include "wl_dbg.h"
  32 #include "wlc_cfg.h"
  33 #include "wlc_rate.h"
  34 #include "wlc_scb.h"
  35 #include "wlc_pub.h"
  36 #include "wlc_key.h"
  37 #include "phy/wlc_phy_hal.h"
  38 #include "wlc_channel.h"
  39 #include "wlc_main.h"
  40 #include "wl_export.h"
  41 #include "wlc_bmac.h"
  42 #include "wlc_stf.h"
  43
  44 #define MIN_SPATIAL_EXPANSION   0
  45 #define MAX_SPATIAL_EXPANSION   1
  46
  47 #define WLC_STF_SS_STBC_RX(wlc) (WLCISNPHY(wlc->band) && \
  48         NREV_GT(wlc->band->phyrev, 3) && NREV_LE(wlc->band->phyrev, 6))
  49
  50 static bool wlc_stf_stbc_tx_set(struct wlc_info *wlc, s32 int_val);
  51 static int wlc_stf_txcore_set(struct wlc_info *wlc, u8 Nsts, u8 val);
  52 static int wlc_stf_spatial_policy_set(struct wlc_info *wlc, int val);
  53 static void wlc_stf_stbc_rx_ht_update(struct wlc_info *wlc, int val);
  54
  55 static void _wlc_stf_phy_txant_upd(struct wlc_info *wlc);
  56 static u16 _wlc_stf_phytxchain_sel(struct wlc_info *wlc, ratespec_t rspec);
  57
  58 #define NSTS_1  1
  59 #define NSTS_2  2
  60 #define NSTS_3  3
  61 #define NSTS_4  4
  62 const u8 txcore_default[5] = {
  63         (0),                    /* bitmap of the core enabled */
  64         (0x01),                 /* For Nsts = 1, enable core 1 */
  65         (0x03),                 /* For Nsts = 2, enable core 1 & 2 */
  66         (0x07),                 /* For Nsts = 3, enable core 1, 2 & 3 */
  67         (0x0f)                  /* For Nsts = 4, enable all cores */
  68 };
  69
  70 static void wlc_stf_stbc_rx_ht_update(struct wlc_info *wlc, int val)
  71 {
  72         /* MIMOPHYs rev3-6 cannot receive STBC with only one rx core active */
  73         if (WLC_STF_SS_STBC_RX(wlc)) {
  74                 if ((wlc->stf->rxstreams == 1) && (val != HT_CAP_RX_STBC_NO))
  75                         return;
  76         }
  77
  78         wlc->ht_cap.cap_info &= ~IEEE80211_HT_CAP_RX_STBC;
  79         wlc->ht_cap.cap_info |= (val << IEEE80211_HT_CAP_RX_STBC_SHIFT);
  80
  81         if (wlc->pub->up) {
  82                 wlc_update_beacon(wlc);
  83                 wlc_update_probe_resp(wlc, true);
  84         }
  85 }
  86
  87 /* every WLC_TEMPSENSE_PERIOD seconds temperature check to decide whether to turn on/off txchain */
  88 void wlc_tempsense_upd(struct wlc_info *wlc)
  89 {
  90         wlc_phy_t *pi = wlc->band->pi;
  91         uint active_chains, txchain;
  92
  93         /* Check if the chip is too hot. Disable one Tx chain, if it is */
  94         /* high 4 bits are for Rx chain, low 4 bits are  for Tx chain */
  95         active_chains = wlc_phy_stf_chain_active_get(pi);
  96         txchain = active_chains & 0xf;
  97
  98         if (wlc->stf->txchain == wlc->stf->hw_txchain) {
  99                 if (txchain && (txchain < wlc->stf->hw_txchain)) {
 100                         /* turn off 1 tx chain */
 101                         wlc_stf_txchain_set(wlc, txchain, true);
 102                 }
 103         } else if (wlc->stf->txchain < wlc->stf->hw_txchain) {
 104                 if (txchain == wlc->stf->hw_txchain) {
 105                         /* turn back on txchain */
 106                         wlc_stf_txchain_set(wlc, txchain, true);
 107                 }
 108         }
 109 }
 110
 111 void
 112 wlc_stf_ss_algo_channel_get(struct wlc_info *wlc, u16 *ss_algo_channel,
 113                             chanspec_t chanspec)
 114 {
 115         tx_power_t power;
 116         u8 siso_mcs_id, cdd_mcs_id, stbc_mcs_id;
 117
 118         /* Clear previous settings */
 119         *ss_algo_channel = 0;
 120
 121         if (!wlc->pub->up) {
 122                 *ss_algo_channel = (u16) -1;
 123                 return;
 124         }
 125
 126         wlc_phy_txpower_get_current(wlc->band->pi, &power,
 127                                     CHSPEC_CHANNEL(chanspec));
 128
 129         siso_mcs_id = (CHSPEC_IS40(chanspec)) ?
 130             WL_TX_POWER_MCS40_SISO_FIRST : WL_TX_POWER_MCS20_SISO_FIRST;
 131         cdd_mcs_id = (CHSPEC_IS40(chanspec)) ?
 132             WL_TX_POWER_MCS40_CDD_FIRST : WL_TX_POWER_MCS20_CDD_FIRST;
 133         stbc_mcs_id = (CHSPEC_IS40(chanspec)) ?
 134             WL_TX_POWER_MCS40_STBC_FIRST : WL_TX_POWER_MCS20_STBC_FIRST;
 135
 136         /* criteria to choose stf mode */
 137
 138         /* the "+3dbm (12 0.25db units)" is to account for the fact that with CDD, tx occurs
 139          * on both chains
 140          */
 141         if (power.target[siso_mcs_id] > (power.target[cdd_mcs_id] + 12))
 142                 setbit(ss_algo_channel, PHY_TXC1_MODE_SISO);
 143         else
 144                 setbit(ss_algo_channel, PHY_TXC1_MODE_CDD);
 145
 146         /* STBC is ORed into to algo channel as STBC requires per-packet SCB capability check
 147          * so cannot be default mode of operation. One of SISO, CDD have to be set
 148          */
 149         if (power.target[siso_mcs_id] <= (power.target[stbc_mcs_id] + 12))
 150                 setbit(ss_algo_channel, PHY_TXC1_MODE_STBC);
 151 }
 152
 153 static bool wlc_stf_stbc_tx_set(struct wlc_info *wlc, s32 int_val)
 154 {
 155         if ((int_val != AUTO) && (int_val != OFF) && (int_val != ON)) {
 156                 return false;
 157         }
 158
 159         if ((int_val == ON) && (wlc->stf->txstreams == 1))
 160                 return false;
 161
 162         if ((int_val == OFF) || (wlc->stf->txstreams == 1)
 163             || !WLC_STBC_CAP_PHY(wlc))
 164                 wlc->ht_cap.cap_info &= ~IEEE80211_HT_CAP_TX_STBC;
 165         else
 166                 wlc->ht_cap.cap_info |= IEEE80211_HT_CAP_TX_STBC;
 167
 168         wlc->bandstate[BAND_2G_INDEX]->band_stf_stbc_tx = (s8) int_val;
 169         wlc->bandstate[BAND_5G_INDEX]->band_stf_stbc_tx = (s8) int_val;
 170
 171         return true;
 172 }
 173
 174 bool wlc_stf_stbc_rx_set(struct wlc_info *wlc, s32 int_val)
 175 {
 176         if ((int_val != HT_CAP_RX_STBC_NO)
 177             && (int_val != HT_CAP_RX_STBC_ONE_STREAM)) {
 178                 return false;
 179         }
 180
 181         if (WLC_STF_SS_STBC_RX(wlc)) {
 182                 if ((int_val != HT_CAP_RX_STBC_NO)
 183                     && (wlc->stf->rxstreams == 1))
 184                         return false;
 185         }
 186
 187         wlc_stf_stbc_rx_ht_update(wlc, int_val);
 188         return true;
 189 }
 190
 191 static int wlc_stf_txcore_set(struct wlc_info *wlc, u8 Nsts, u8 core_mask)
 192 {
 193         BCMMSG(wlc->wiphy, "wl%d: Nsts %d core_mask %x\n",
 194                  wlc->pub->unit, Nsts, core_mask);
 195
 196         if (WLC_BITSCNT(core_mask) > wlc->stf->txstreams) {
 197                 core_mask = 0;
 198         }
 199
 200         if ((WLC_BITSCNT(core_mask) == wlc->stf->txstreams) &&
 201             ((core_mask & ~wlc->stf->txchain)
 202              || !(core_mask & wlc->stf->txchain))) {
 203                 core_mask = wlc->stf->txchain;
 204         }
 205
 206         wlc->stf->txcore[Nsts] = core_mask;
 207         /* Nsts = 1..4, txcore index = 1..4 */
 208         if (Nsts == 1) {
 209                 /* Needs to update beacon and ucode generated response
 210                  * frames when 1 stream core map changed
 211                  */
 212                 wlc->stf->phytxant = core_mask << PHY_TXC_ANT_SHIFT;
 213                 wlc_bmac_txant_set(wlc->hw, wlc->stf->phytxant);
 214                 if (wlc->clk) {
 215                         wlc_suspend_mac_and_wait(wlc);
 216                         wlc_beacon_phytxctl_txant_upd(wlc, wlc->bcn_rspec);
 217                         wlc_enable_mac(wlc);
 218                 }
 219         }
 220
 221         return 0;
 222 }
 223
 224 static int wlc_stf_spatial_policy_set(struct wlc_info *wlc, int val)
 225 {
 226         int i;
 227         u8 core_mask = 0;
 228
 229         BCMMSG(wlc->wiphy, "wl%d: val %x\n", wlc->pub->unit, val);
 230
 231         wlc->stf->spatial_policy = (s8) val;
 232         for (i = 1; i <= MAX_STREAMS_SUPPORTED; i++) {
 233                 core_mask = (val == MAX_SPATIAL_EXPANSION) ?
 234                     wlc->stf->txchain : txcore_default[i];
 235                 wlc_stf_txcore_set(wlc, (u8) i, core_mask);
 236         }
 237         return 0;
 238 }
 239
 240 int wlc_stf_txchain_set(struct wlc_info *wlc, s32 int_val, bool force)
 241 {
 242         u8 txchain = (u8) int_val;
 243         u8 txstreams;
 244         uint i;
 245
 246         if (wlc->stf->txchain == txchain)
 247                 return 0;
 248
 249         if ((txchain & ~wlc->stf->hw_txchain)
 250             || !(txchain & wlc->stf->hw_txchain))
 251                 return -EINVAL;
 252
 253         /* if nrate override is configured to be non-SISO STF mode, reject reducing txchain to 1 */
 254         txstreams = (u8) WLC_BITSCNT(txchain);
 255         if (txstreams > MAX_STREAMS_SUPPORTED)
 256                 return -EINVAL;
 257
 258         if (txstreams == 1) {
 259                 for (i = 0; i < NBANDS(wlc); i++)
 260                         if ((RSPEC_STF(wlc->bandstate[i]->rspec_override) !=
 261                              PHY_TXC1_MODE_SISO)
 262                             || (RSPEC_STF(wlc->bandstate[i]->mrspec_override) !=
 263                                 PHY_TXC1_MODE_SISO)) {
 264                                 if (!force)
 265                                         return -EBADE;
 266
 267                                 /* over-write the override rspec */
 268                                 if (RSPEC_STF(wlc->bandstate[i]->rspec_override)
 269                                     != PHY_TXC1_MODE_SISO) {
 270                                         wlc->bandstate[i]->rspec_override = 0;
 271                                         wiphy_err(wlc->wiphy, "%s(): temp "
 272                                                   "sense override non-SISO "
 273                                                   "rspec_override\n",
 274                                                   __func__);
 275                                 }
 276                                 if (RSPEC_STF
 277                                     (wlc->bandstate[i]->mrspec_override) !=
 278                                     PHY_TXC1_MODE_SISO) {
 279                                         wlc->bandstate[i]->mrspec_override = 0;
 280                                         wiphy_err(wlc->wiphy, "%s(): temp "
 281                                                   "sense override non-SISO "
 282                                                   "mrspec_override\n",
 283                                                   __func__);
 284                                 }
 285                         }
 286         }
 287
 288         wlc->stf->txchain = txchain;
 289         wlc->stf->txstreams = txstreams;
 290         wlc_stf_stbc_tx_set(wlc, wlc->band->band_stf_stbc_tx);
 291         wlc_stf_ss_update(wlc, wlc->bandstate[BAND_2G_INDEX]);
 292         wlc_stf_ss_update(wlc, wlc->bandstate[BAND_5G_INDEX]);
 293         wlc->stf->txant =
 294             (wlc->stf->txstreams == 1) ? ANT_TX_FORCE_0 : ANT_TX_DEF;
 295         _wlc_stf_phy_txant_upd(wlc);
 296
 297         wlc_phy_stf_chain_set(wlc->band->pi, wlc->stf->txchain,
 298                               wlc->stf->rxchain);
 299
 300         for (i = 1; i <= MAX_STREAMS_SUPPORTED; i++)
 301                 wlc_stf_txcore_set(wlc, (u8) i, txcore_default[i]);
 302
 303         return 0;
 304 }
 305
 306 /* update wlc->stf->ss_opmode which represents the operational stf_ss mode we're using */
 307 int wlc_stf_ss_update(struct wlc_info *wlc, struct wlcband *band)
 308 {
 309         int ret_code = 0;
 310         u8 prev_stf_ss;
 311         u8 upd_stf_ss;
 312
 313         prev_stf_ss = wlc->stf->ss_opmode;
 314
 315         /* NOTE: opmode can only be SISO or CDD as STBC is decided on a per-packet basis */
 316         if (WLC_STBC_CAP_PHY(wlc) &&
 317             wlc->stf->ss_algosel_auto
 318             && (wlc->stf->ss_algo_channel != (u16) -1)) {
 319                 upd_stf_ss = (wlc->stf->no_cddstbc || (wlc->stf->txstreams == 1)
 320                               || isset(&wlc->stf->ss_algo_channel,
 321                                        PHY_TXC1_MODE_SISO)) ? PHY_TXC1_MODE_SISO
 322                     : PHY_TXC1_MODE_CDD;
 323         } else {
 324                 if (wlc->band != band)
 325                         return ret_code;
 326                 upd_stf_ss = (wlc->stf->no_cddstbc
 327                               || (wlc->stf->txstreams ==
 328                                   1)) ? PHY_TXC1_MODE_SISO : band->
 329                     band_stf_ss_mode;
 330         }
 331         if (prev_stf_ss != upd_stf_ss) {
 332                 wlc->stf->ss_opmode = upd_stf_ss;
 333                 wlc_bmac_band_stf_ss_set(wlc->hw, upd_stf_ss);
 334         }
 335
 336         return ret_code;
 337 }
 338
 339 int wlc_stf_attach(struct wlc_info *wlc)
 340 {
 341         wlc->bandstate[BAND_2G_INDEX]->band_stf_ss_mode = PHY_TXC1_MODE_SISO;
 342         wlc->bandstate[BAND_5G_INDEX]->band_stf_ss_mode = PHY_TXC1_MODE_CDD;
 343
 344         if (WLCISNPHY(wlc->band) &&
 345             (wlc_phy_txpower_hw_ctrl_get(wlc->band->pi) != PHY_TPC_HW_ON))
 346                 wlc->bandstate[BAND_2G_INDEX]->band_stf_ss_mode =
 347                     PHY_TXC1_MODE_CDD;
 348         wlc_stf_ss_update(wlc, wlc->bandstate[BAND_2G_INDEX]);
 349         wlc_stf_ss_update(wlc, wlc->bandstate[BAND_5G_INDEX]);
 350
 351         wlc_stf_stbc_rx_ht_update(wlc, HT_CAP_RX_STBC_NO);
 352         wlc->bandstate[BAND_2G_INDEX]->band_stf_stbc_tx = OFF;
 353         wlc->bandstate[BAND_5G_INDEX]->band_stf_stbc_tx = OFF;
 354
 355         if (WLC_STBC_CAP_PHY(wlc)) {
 356                 wlc->stf->ss_algosel_auto = true;
 357                 wlc->stf->ss_algo_channel = (u16) -1;   /* Init the default value */
 358         }
 359         return 0;
 360 }
 361
 362 void wlc_stf_detach(struct wlc_info *wlc)
 363 {
 364 }
 365
 366 int wlc_stf_ant_txant_validate(struct wlc_info *wlc, s8 val)
 367 {
 368         int bcmerror = 0;
 369
 370         /* when there is only 1 tx_streams, don't allow to change the txant */
 371         if (WLCISNPHY(wlc->band) && (wlc->stf->txstreams == 1))
 372                 return ((val == wlc->stf->txant) ? bcmerror : -EINVAL);
 373
 374         switch (val) {
 375         case -1:
 376                 val = ANT_TX_DEF;
 377                 break;
 378         case 0:
 379                 val = ANT_TX_FORCE_0;
 380                 break;
 381         case 1:
 382                 val = ANT_TX_FORCE_1;
 383                 break;
 384         case 3:
 385                 val = ANT_TX_LAST_RX;
 386                 break;
 387         default:
 388                 bcmerror = -EINVAL;
 389                 break;
 390         }
 391
 392         if (bcmerror == 0)
 393                 wlc->stf->txant = (s8) val;
 394
 395         return bcmerror;
 396
 397 }
 398
 399 /*
 400  * Centralized txant update function. call it whenever wlc->stf->txant and/or wlc->stf->txchain
 401  *  change
 402  *
 403  * Antennas are controlled by ucode indirectly, which drives PHY or GPIO to
 404  *   achieve various tx/rx antenna selection schemes
 405  *
 406  * legacy phy, bit 6 and bit 7 means antenna 0 and 1 respectively, bit6+bit7 means auto(last rx)
 407  * for NREV<3, bit 6 and bit 7 means antenna 0 and 1 respectively, bit6+bit7 means last rx and
 408  *    do tx-antenna selection for SISO transmissions
 409  * for NREV=3, bit 6 and bit _8_ means antenna 0 and 1 respectively, bit6+bit7 means last rx and
 410  *    do tx-antenna selection for SISO transmissions
 411  * for NREV>=7, bit 6 and bit 7 mean antenna 0 and 1 respectively, nit6+bit7 means both cores active
 412 */
 413 static void _wlc_stf_phy_txant_upd(struct wlc_info *wlc)
 414 {
 415         s8 txant;
 416
 417         txant = (s8) wlc->stf->txant;
 418         if (WLC_PHY_11N_CAP(wlc->band)) {
 419                 if (txant == ANT_TX_FORCE_0) {
 420                         wlc->stf->phytxant = PHY_TXC_ANT_0;
 421                 } else if (txant == ANT_TX_FORCE_1) {
 422                         wlc->stf->phytxant = PHY_TXC_ANT_1;
 423
 424                         if (WLCISNPHY(wlc->band) &&
 425                             NREV_GE(wlc->band->phyrev, 3)
 426                             && NREV_LT(wlc->band->phyrev, 7)) {
 427                                 wlc->stf->phytxant = PHY_TXC_ANT_2;
 428                         }
 429                 } else {
 430                         if (WLCISLCNPHY(wlc->band) || WLCISSSLPNPHY(wlc->band))
 431                                 wlc->stf->phytxant = PHY_TXC_LCNPHY_ANT_LAST;
 432                         else {
 433                                 /* catch out of sync wlc->stf->txcore */
 434                                 WARN_ON(wlc->stf->txchain <= 0);
 435                                 wlc->stf->phytxant =
 436                                     wlc->stf->txchain << PHY_TXC_ANT_SHIFT;
 437                         }
 438                 }
 439         } else {
 440                 if (txant == ANT_TX_FORCE_0)
 441                         wlc->stf->phytxant = PHY_TXC_OLD_ANT_0;
 442                 else if (txant == ANT_TX_FORCE_1)
 443                         wlc->stf->phytxant = PHY_TXC_OLD_ANT_1;
 444                 else
 445                         wlc->stf->phytxant = PHY_TXC_OLD_ANT_LAST;
 446         }
 447
 448         wlc_bmac_txant_set(wlc->hw, wlc->stf->phytxant);
 449 }
 450
 451 void wlc_stf_phy_txant_upd(struct wlc_info *wlc)
 452 {
 453         _wlc_stf_phy_txant_upd(wlc);
 454 }
 455
 456 void wlc_stf_phy_chain_calc(struct wlc_info *wlc)
 457 {
 458         /* get available rx/tx chains */
 459         wlc->stf->hw_txchain = (u8) getintvar(wlc->pub->vars, "txchain");
 460         wlc->stf->hw_rxchain = (u8) getintvar(wlc->pub->vars, "rxchain");
 461
 462         /* these parameter are intended to be used for all PHY types */
 463         if (wlc->stf->hw_txchain == 0 || wlc->stf->hw_txchain == 0xf) {
 464                 if (WLCISNPHY(wlc->band)) {
 465                         wlc->stf->hw_txchain = TXCHAIN_DEF_NPHY;
 466                 } else {
 467                         wlc->stf->hw_txchain = TXCHAIN_DEF;
 468                 }
 469         }
 470
 471         wlc->stf->txchain = wlc->stf->hw_txchain;
 472         wlc->stf->txstreams = (u8) WLC_BITSCNT(wlc->stf->hw_txchain);
 473
 474         if (wlc->stf->hw_rxchain == 0 || wlc->stf->hw_rxchain == 0xf) {
 475                 if (WLCISNPHY(wlc->band)) {
 476                         wlc->stf->hw_rxchain = RXCHAIN_DEF_NPHY;
 477                 } else {
 478                         wlc->stf->hw_rxchain = RXCHAIN_DEF;
 479                 }
 480         }
 481
 482         wlc->stf->rxchain = wlc->stf->hw_rxchain;
 483         wlc->stf->rxstreams = (u8) WLC_BITSCNT(wlc->stf->hw_rxchain);
 484
 485         /* initialize the txcore table */
 486         memcpy(wlc->stf->txcore, txcore_default, sizeof(wlc->stf->txcore));
 487
 488         /* default spatial_policy */
 489         wlc->stf->spatial_policy = MIN_SPATIAL_EXPANSION;
 490         wlc_stf_spatial_policy_set(wlc, MIN_SPATIAL_EXPANSION);
 491 }
 492
 493 static u16 _wlc_stf_phytxchain_sel(struct wlc_info *wlc, ratespec_t rspec)
 494 {
 495         u16 phytxant = wlc->stf->phytxant;
 496
 497         if (RSPEC_STF(rspec) != PHY_TXC1_MODE_SISO) {
 498                 phytxant = wlc->stf->txchain << PHY_TXC_ANT_SHIFT;
 499         } else if (wlc->stf->txant == ANT_TX_DEF)
 500                 phytxant = wlc->stf->txchain << PHY_TXC_ANT_SHIFT;
 501         phytxant &= PHY_TXC_ANT_MASK;
 502         return phytxant;
 503 }
 504
 505 u16 wlc_stf_phytxchain_sel(struct wlc_info *wlc, ratespec_t rspec)
 506 {
 507         return _wlc_stf_phytxchain_sel(wlc, rspec);
 508 }
 509
 510 u16 wlc_stf_d11hdrs_phyctl_txant(struct wlc_info *wlc, ratespec_t rspec)
 511 {
 512         u16 phytxant = wlc->stf->phytxant;
 513         u16 mask = PHY_TXC_ANT_MASK;
 514
 515         /* for non-siso rates or default setting, use the available chains */
 516         if (WLCISNPHY(wlc->band)) {
 517                 phytxant = _wlc_stf_phytxchain_sel(wlc, rspec);
 518                 mask = PHY_TXC_HTANT_MASK;
 519         }
 520         phytxant |= phytxant & mask;
 521         return phytxant;
 522 }