The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/dev/ath/if_ath_tx_ht.c

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    1 /*-
    2  * Copyright (c) 2011 Adrian Chadd, Xenion Pty Ltd.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer,
   10  *    without modification.
   11  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
   12  *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
   13  *    redistribution must be conditioned upon including a substantially
   14  *    similar Disclaimer requirement for further binary redistribution.
   15  *
   16  * NO WARRANTY
   17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   19  * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
   20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
   21  * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
   22  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
   25  * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
   27  * THE POSSIBILITY OF SUCH DAMAGES.
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD: releng/11.2/sys/dev/ath/if_ath_tx_ht.c 331722 2018-03-29 02:50:57Z eadler $");
   32 
   33 #include "opt_inet.h"
   34 #include "opt_ath.h"
   35 #include "opt_wlan.h"
   36 
   37 #include <sys/param.h>
   38 #include <sys/systm.h>
   39 #include <sys/sysctl.h>
   40 #include <sys/mbuf.h>
   41 #include <sys/malloc.h>
   42 #include <sys/lock.h>
   43 #include <sys/mutex.h>
   44 #include <sys/kernel.h>
   45 #include <sys/socket.h>
   46 #include <sys/sockio.h>
   47 #include <sys/errno.h>
   48 #include <sys/callout.h>
   49 #include <sys/bus.h>
   50 #include <sys/endian.h>
   51 #include <sys/kthread.h>
   52 #include <sys/taskqueue.h>
   53 #include <sys/priv.h>
   54 
   55 #include <machine/bus.h>
   56 
   57 #include <net/if.h>
   58 #include <net/if_dl.h>
   59 #include <net/if_media.h>
   60 #include <net/if_types.h>
   61 #include <net/if_arp.h>
   62 #include <net/ethernet.h>
   63 #include <net/if_llc.h>
   64 
   65 #include <net80211/ieee80211_var.h>
   66 #include <net80211/ieee80211_regdomain.h>
   67 #ifdef IEEE80211_SUPPORT_SUPERG
   68 #include <net80211/ieee80211_superg.h>
   69 #endif
   70 #ifdef IEEE80211_SUPPORT_TDMA
   71 #include <net80211/ieee80211_tdma.h>
   72 #endif
   73 
   74 #include <net/bpf.h>
   75 
   76 #ifdef INET
   77 #include <netinet/in.h>
   78 #include <netinet/if_ether.h>
   79 #endif
   80 
   81 #include <dev/ath/if_athvar.h>
   82 #include <dev/ath/ath_hal/ah_devid.h>           /* XXX for softled */
   83 #include <dev/ath/ath_hal/ah_diagcodes.h>
   84 
   85 #ifdef ATH_TX99_DIAG
   86 #include <dev/ath/ath_tx99/ath_tx99.h>
   87 #endif
   88 
   89 #include <dev/ath/if_ath_tx.h>          /* XXX for some support functions */
   90 #include <dev/ath/if_ath_tx_ht.h>
   91 #include <dev/ath/if_athrate.h>
   92 #include <dev/ath/if_ath_debug.h>
   93 
   94 /*
   95  * XXX net80211?
   96  */
   97 #define IEEE80211_AMPDU_SUBFRAME_DEFAULT                32
   98 
   99 #define ATH_AGGR_DELIM_SZ       4       /* delimiter size */
  100 #define ATH_AGGR_MINPLEN        256     /* in bytes, minimum packet length */
  101 /* number of delimiters for encryption padding */
  102 #define ATH_AGGR_ENCRYPTDELIM   10
  103 
  104 /*
  105  * returns delimiter padding required given the packet length
  106  */
  107 #define ATH_AGGR_GET_NDELIM(_len)                                       \
  108             (((((_len) + ATH_AGGR_DELIM_SZ) < ATH_AGGR_MINPLEN) ?       \
  109             (ATH_AGGR_MINPLEN - (_len) - ATH_AGGR_DELIM_SZ) : 0) >> 2)
  110 
  111 #define PADBYTES(_len)          ((4 - ((_len) % 4)) % 4)
  112 
  113 int ath_max_4ms_framelen[4][32] = {
  114         [MCS_HT20] = {
  115                 3212,  6432,  9648,  12864,  19300,  25736,  28952,  32172,
  116                 6424,  12852, 19280, 25708,  38568,  51424,  57852,  64280,
  117                 9628,  19260, 28896, 38528,  57792,  65532,  65532,  65532,
  118                 12828, 25656, 38488, 51320,  65532,  65532,  65532,  65532,
  119         },
  120         [MCS_HT20_SGI] = {
  121                 3572,  7144,  10720,  14296,  21444,  28596,  32172,  35744,
  122                 7140,  14284, 21428,  28568,  42856,  57144,  64288,  65532,
  123                 10700, 21408, 32112,  42816,  64228,  65532,  65532,  65532,
  124                 14256, 28516, 42780,  57040,  65532,  65532,  65532,  65532,
  125         },
  126         [MCS_HT40] = {
  127                 6680,  13360,  20044,  26724,  40092,  53456,  60140,  65532,
  128                 13348, 26700,  40052,  53400,  65532,  65532,  65532,  65532,
  129                 20004, 40008,  60016,  65532,  65532,  65532,  65532,  65532,
  130                 26644, 53292,  65532,  65532,  65532,  65532,  65532,  65532,
  131         },
  132         [MCS_HT40_SGI] = {
  133                 7420,  14844,  22272,  29696,  44544,  59396,  65532,  65532,
  134                 14832, 29668,  44504,  59340,  65532,  65532,  65532,  65532,
  135                 22232, 44464,  65532,  65532,  65532,  65532,  65532,  65532,
  136                 29616, 59232,  65532,  65532,  65532,  65532,  65532,  65532,
  137         }
  138 };
  139 
  140 /*
  141  * XXX should be in net80211
  142  */
  143 static int ieee80211_mpdudensity_map[] = {
  144         0,              /* IEEE80211_HTCAP_MPDUDENSITY_NA */
  145         25,             /* IEEE80211_HTCAP_MPDUDENSITY_025 */
  146         50,             /* IEEE80211_HTCAP_MPDUDENSITY_05 */
  147         100,            /* IEEE80211_HTCAP_MPDUDENSITY_1 */
  148         200,            /* IEEE80211_HTCAP_MPDUDENSITY_2 */
  149         400,            /* IEEE80211_HTCAP_MPDUDENSITY_4 */
  150         800,            /* IEEE80211_HTCAP_MPDUDENSITY_8 */
  151         1600,           /* IEEE80211_HTCAP_MPDUDENSITY_16 */
  152 };
  153 
  154 /*
  155  * XXX should be in the HAL/net80211 ?
  156  */
  157 #define BITS_PER_BYTE           8
  158 #define OFDM_PLCP_BITS          22
  159 #define HT_RC_2_MCS(_rc)        ((_rc) & 0x7f)
  160 #define HT_RC_2_STREAMS(_rc)    ((((_rc) & 0x78) >> 3) + 1)
  161 #define L_STF                   8
  162 #define L_LTF                   8
  163 #define L_SIG                   4
  164 #define HT_SIG                  8
  165 #define HT_STF                  4
  166 #define HT_LTF(_ns)             (4 * (_ns))
  167 #define SYMBOL_TIME(_ns)        ((_ns) << 2)            // ns * 4 us
  168 #define SYMBOL_TIME_HALFGI(_ns) (((_ns) * 18 + 4) / 5)  // ns * 3.6 us
  169 #define NUM_SYMBOLS_PER_USEC(_usec)     (_usec >> 2)
  170 #define NUM_SYMBOLS_PER_USEC_HALFGI(_usec)      (((_usec*5)-4)/18)
  171 #define IS_HT_RATE(_rate)       ((_rate) & 0x80)
  172 
  173 const uint32_t bits_per_symbol[][2] = {
  174     /* 20MHz 40MHz */
  175     {    26,   54 },     //  0: BPSK
  176     {    52,  108 },     //  1: QPSK 1/2
  177     {    78,  162 },     //  2: QPSK 3/4
  178     {   104,  216 },     //  3: 16-QAM 1/2
  179     {   156,  324 },     //  4: 16-QAM 3/4
  180     {   208,  432 },     //  5: 64-QAM 2/3
  181     {   234,  486 },     //  6: 64-QAM 3/4
  182     {   260,  540 },     //  7: 64-QAM 5/6
  183     {    52,  108 },     //  8: BPSK
  184     {   104,  216 },     //  9: QPSK 1/2
  185     {   156,  324 },     // 10: QPSK 3/4
  186     {   208,  432 },     // 11: 16-QAM 1/2
  187     {   312,  648 },     // 12: 16-QAM 3/4
  188     {   416,  864 },     // 13: 64-QAM 2/3
  189     {   468,  972 },     // 14: 64-QAM 3/4
  190     {   520, 1080 },     // 15: 64-QAM 5/6
  191     {    78,  162 },     // 16: BPSK
  192     {   156,  324 },     // 17: QPSK 1/2
  193     {   234,  486 },     // 18: QPSK 3/4
  194     {   312,  648 },     // 19: 16-QAM 1/2
  195     {   468,  972 },     // 20: 16-QAM 3/4
  196     {   624, 1296 },     // 21: 64-QAM 2/3
  197     {   702, 1458 },     // 22: 64-QAM 3/4
  198     {   780, 1620 },     // 23: 64-QAM 5/6
  199     {   104,  216 },     // 24: BPSK
  200     {   208,  432 },     // 25: QPSK 1/2
  201     {   312,  648 },     // 26: QPSK 3/4
  202     {   416,  864 },     // 27: 16-QAM 1/2
  203     {   624, 1296 },     // 28: 16-QAM 3/4
  204     {   832, 1728 },     // 29: 64-QAM 2/3
  205     {   936, 1944 },     // 30: 64-QAM 3/4
  206     {  1040, 2160 },     // 31: 64-QAM 5/6
  207 };
  208 
  209 /*
  210  * Fill in the rate array information based on the current
  211  * node configuration and the choices made by the rate
  212  * selection code and ath_buf setup code.
  213  *
  214  * Later on, this may end up also being made by the
  215  * rate control code, but for now it can live here.
  216  *
  217  * This needs to be called just before the packet is
  218  * queued to the software queue or hardware queue,
  219  * so all of the needed fields in bf_state are setup.
  220  */
  221 void
  222 ath_tx_rate_fill_rcflags(struct ath_softc *sc, struct ath_buf *bf)
  223 {
  224         struct ieee80211_node *ni = bf->bf_node;
  225         struct ieee80211vap *vap = ni->ni_vap;
  226         struct ieee80211com *ic = ni->ni_ic;
  227         const HAL_RATE_TABLE *rt = sc->sc_currates;
  228         struct ath_rc_series *rc = bf->bf_state.bfs_rc;
  229         uint8_t rate;
  230         int i;
  231         int do_ldpc;
  232         int do_stbc;
  233 
  234         /*
  235          * We only do LDPC if the rate is 11n, both we and the
  236          * receiver support LDPC and it's enabled.
  237          *
  238          * It's a global flag, not a per-try flag, so we clear
  239          * it if any of the rate entries aren't 11n.
  240          */
  241         do_ldpc = 0;
  242         if ((ni->ni_vap->iv_htcaps & IEEE80211_HTCAP_LDPC) &&
  243             (ni->ni_htcap & IEEE80211_HTCAP_LDPC))
  244                 do_ldpc = 1;
  245         do_stbc = 0;
  246 
  247         for (i = 0; i < ATH_RC_NUM; i++) {
  248                 rc[i].flags = 0;
  249                 if (rc[i].tries == 0)
  250                         continue;
  251 
  252                 rate = rt->info[rc[i].rix].rateCode;
  253 
  254                 /*
  255                  * Only enable short preamble for legacy rates
  256                  */
  257                 if ((! IS_HT_RATE(rate)) && bf->bf_state.bfs_shpream)
  258                         rate |= rt->info[rc[i].rix].shortPreamble;
  259 
  260                 /*
  261                  * Save this, used by the TX and completion code
  262                  */
  263                 rc[i].ratecode = rate;
  264 
  265                 if (bf->bf_state.bfs_txflags &
  266                     (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA))
  267                         rc[i].flags |= ATH_RC_RTSCTS_FLAG;
  268 
  269                 /*
  270                  * If we can't do LDPC, don't.
  271                  */
  272                 if (! IS_HT_RATE(rate))
  273                         do_ldpc = 0;
  274 
  275                 /* Only enable shortgi, 2040, dual-stream if HT is set */
  276                 if (IS_HT_RATE(rate)) {
  277                         rc[i].flags |= ATH_RC_HT_FLAG;
  278 
  279                         if (ni->ni_chw == 40)
  280                                 rc[i].flags |= ATH_RC_CW40_FLAG;
  281 
  282                         if (ni->ni_chw == 40 &&
  283                             ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI40 &&
  284                             ni->ni_htcap & IEEE80211_HTCAP_SHORTGI40 &&
  285                             vap->iv_flags_ht & IEEE80211_FHT_SHORTGI40)
  286                                 rc[i].flags |= ATH_RC_SGI_FLAG;
  287 
  288                         if (ni->ni_chw == 20 &&
  289                             ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI20 &&
  290                             ni->ni_htcap & IEEE80211_HTCAP_SHORTGI20 &&
  291                             vap->iv_flags_ht & IEEE80211_FHT_SHORTGI20)
  292                                 rc[i].flags |= ATH_RC_SGI_FLAG;
  293 
  294                         /*
  295                          * If we have STBC TX enabled and the receiver
  296                          * can receive (at least) 1 stream STBC, AND it's
  297                          * MCS 0-7, AND we have at least two chains enabled,
  298                          * enable STBC.
  299                          *
  300                          * XXX TODO: .. and the rate is an 11n rate?
  301                          */
  302                         if (ic->ic_htcaps & IEEE80211_HTCAP_TXSTBC &&
  303                             ni->ni_vap->iv_flags_ht & IEEE80211_FHT_STBC_TX &&
  304                             ni->ni_htcap & IEEE80211_HTCAP_RXSTBC_1STREAM &&
  305                             (sc->sc_cur_txchainmask > 1) &&
  306                             HT_RC_2_STREAMS(rate) == 1) {
  307                                 rc[i].flags |= ATH_RC_STBC_FLAG;
  308                                 do_stbc = 1;
  309                         }
  310 
  311                         /*
  312                          * Dual / Triple stream rate?
  313                          */
  314                         if (HT_RC_2_STREAMS(rate) == 2)
  315                                 rc[i].flags |= ATH_RC_DS_FLAG;
  316                         else if (HT_RC_2_STREAMS(rate) == 3)
  317                                 rc[i].flags |= ATH_RC_TS_FLAG;
  318                 }
  319 
  320                 /*
  321                  * Calculate the maximum TX power cap for the current
  322                  * node.
  323                  */
  324                 rc[i].tx_power_cap = ieee80211_get_node_txpower(ni);
  325 
  326                 /*
  327                  * Calculate the maximum 4ms frame length based
  328                  * on the MCS rate, SGI and channel width flags.
  329                  */
  330                 if ((rc[i].flags & ATH_RC_HT_FLAG) &&
  331                     (HT_RC_2_MCS(rate) < 32)) {
  332                         int j;
  333                         if (rc[i].flags & ATH_RC_CW40_FLAG) {
  334                                 if (rc[i].flags & ATH_RC_SGI_FLAG)
  335                                         j = MCS_HT40_SGI;
  336                                 else
  337                                         j = MCS_HT40;
  338                         } else {
  339                                 if (rc[i].flags & ATH_RC_SGI_FLAG)
  340                                         j = MCS_HT20_SGI;
  341                                 else
  342                                         j = MCS_HT20;
  343                         }
  344                         rc[i].max4msframelen =
  345                             ath_max_4ms_framelen[j][HT_RC_2_MCS(rate)];
  346                 } else
  347                         rc[i].max4msframelen = 0;
  348                 DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  349                     "%s: i=%d, rate=0x%x, flags=0x%x, max4ms=%d\n",
  350                     __func__, i, rate, rc[i].flags, rc[i].max4msframelen);
  351         }
  352 
  353         /*
  354          * LDPC is a global flag, so ...
  355          */
  356         if (do_ldpc) {
  357                 bf->bf_state.bfs_txflags |= HAL_TXDESC_LDPC;
  358                 sc->sc_stats.ast_tx_ldpc++;
  359         }
  360 
  361         if (do_stbc) {
  362                 sc->sc_stats.ast_tx_stbc++;
  363         }
  364 }
  365 
  366 /*
  367  * Return the number of delimiters to be added to
  368  * meet the minimum required mpdudensity.
  369  *
  370  * Caller should make sure that the rate is HT.
  371  *
  372  * TODO: is this delimiter calculation supposed to be the
  373  * total frame length, the hdr length, the data length (including
  374  * delimiters, padding, CRC, etc) or ?
  375  *
  376  * TODO: this should ensure that the rate control information
  377  * HAS been setup for the first rate.
  378  *
  379  * TODO: ensure this is only called for MCS rates.
  380  *
  381  * TODO: enforce MCS < 31
  382  */
  383 static int
  384 ath_compute_num_delims(struct ath_softc *sc, struct ath_buf *first_bf,
  385     uint16_t pktlen)
  386 {
  387         const HAL_RATE_TABLE *rt = sc->sc_currates;
  388         struct ieee80211_node *ni = first_bf->bf_node;
  389         struct ieee80211vap *vap = ni->ni_vap;
  390         int ndelim, mindelim = 0;
  391         int mpdudensity;         /* in 1/100'th of a microsecond */
  392         uint8_t rc, rix, flags;
  393         int width, half_gi;
  394         uint32_t nsymbits, nsymbols;
  395         uint16_t minlen;
  396 
  397         /*
  398          * vap->iv_ampdu_density is a value, rather than the actual
  399          * density.
  400          */
  401         if (vap->iv_ampdu_density > IEEE80211_HTCAP_MPDUDENSITY_16)
  402                 mpdudensity = 1600;             /* maximum density */
  403         else
  404                 mpdudensity = ieee80211_mpdudensity_map[vap->iv_ampdu_density];
  405 
  406         /* Select standard number of delimiters based on frame length */
  407         ndelim = ATH_AGGR_GET_NDELIM(pktlen);
  408 
  409         /*
  410          * If encryption is enabled, add extra delimiters to let the
  411          * crypto hardware catch up. This could be tuned per-MAC and
  412          * per-rate, but for now we'll simply assume encryption is
  413          * always enabled.
  414          *
  415          * Also note that the Atheros reference driver inserts two
  416          * delimiters by default for pre-AR9380 peers.  This will
  417          * include "that" required delimiter.
  418          */
  419         ndelim += ATH_AGGR_ENCRYPTDELIM;
  420 
  421         /*
  422          * For AR9380, there's a minimum number of delimeters
  423          * required when doing RTS.
  424          *
  425          * XXX TODO: this is only needed if (a) RTS/CTS is enabled, and
  426          * XXX (b) this is the first sub-frame in the aggregate.
  427          */
  428         if (sc->sc_use_ent && (sc->sc_ent_cfg & AH_ENT_RTSCTS_DELIM_WAR)
  429             && ndelim < AH_FIRST_DESC_NDELIMS)
  430                 ndelim = AH_FIRST_DESC_NDELIMS;
  431 
  432         /*
  433          * If sc_delim_min_pad is non-zero, enforce it as the minimum
  434          * pad delimiter count.
  435          */
  436         if (sc->sc_delim_min_pad != 0)
  437                 ndelim = MAX(ndelim, sc->sc_delim_min_pad);
  438 
  439         DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  440             "%s: pktlen=%d, ndelim=%d, mpdudensity=%d\n",
  441             __func__, pktlen, ndelim, mpdudensity);
  442 
  443         /*
  444          * If the MPDU density is 0, we can return here.
  445          * Otherwise, we need to convert the desired mpdudensity
  446          * into a byte length, based on the rate in the subframe.
  447          */
  448         if (mpdudensity == 0)
  449                 return ndelim;
  450 
  451         /*
  452          * Convert desired mpdu density from microeconds to bytes based
  453          * on highest rate in rate series (i.e. first rate) to determine
  454          * required minimum length for subframe. Take into account
  455          * whether high rate is 20 or 40Mhz and half or full GI.
  456          */
  457         rix = first_bf->bf_state.bfs_rc[0].rix;
  458         rc = rt->info[rix].rateCode;
  459         flags = first_bf->bf_state.bfs_rc[0].flags;
  460         width = !! (flags & ATH_RC_CW40_FLAG);
  461         half_gi = !! (flags & ATH_RC_SGI_FLAG);
  462 
  463         /*
  464          * mpdudensity is in 1/100th of a usec, so divide by 100
  465          */
  466         if (half_gi)
  467                 nsymbols = NUM_SYMBOLS_PER_USEC_HALFGI(mpdudensity);
  468         else
  469                 nsymbols = NUM_SYMBOLS_PER_USEC(mpdudensity);
  470         nsymbols /= 100;
  471 
  472         if (nsymbols == 0)
  473                 nsymbols = 1;
  474 
  475         nsymbits = bits_per_symbol[HT_RC_2_MCS(rc)][width];
  476         minlen = (nsymbols * nsymbits) / BITS_PER_BYTE;
  477 
  478         /*
  479          * Min length is the minimum frame length for the
  480          * required MPDU density.
  481          */
  482         if (pktlen < minlen) {
  483                 mindelim = (minlen - pktlen) / ATH_AGGR_DELIM_SZ;
  484                 ndelim = MAX(mindelim, ndelim);
  485         }
  486 
  487         DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  488             "%s: pktlen=%d, minlen=%d, rix=%x, rc=%x, width=%d, hgi=%d, ndelim=%d\n",
  489             __func__, pktlen, minlen, rix, rc, width, half_gi, ndelim);
  490 
  491         return ndelim;
  492 }
  493 
  494 /*
  495  * Fetch the aggregation limit.
  496  *
  497  * It's the lowest of the four rate series 4ms frame length.
  498  */
  499 static int
  500 ath_get_aggr_limit(struct ath_softc *sc, struct ath_buf *bf)
  501 {
  502         int amin = ATH_AGGR_MAXSIZE;
  503         int i;
  504 
  505         if (sc->sc_aggr_limit > 0 && sc->sc_aggr_limit < ATH_AGGR_MAXSIZE)
  506                 amin = sc->sc_aggr_limit;
  507 
  508         for (i = 0; i < ATH_RC_NUM; i++) {
  509                 if (bf->bf_state.bfs_rc[i].tries == 0)
  510                         continue;
  511                 amin = MIN(amin, bf->bf_state.bfs_rc[i].max4msframelen);
  512         }
  513 
  514         DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: max frame len= %d\n",
  515             __func__, amin);
  516 
  517         return amin;
  518 }
  519 
  520 /*
  521  * Setup a 11n rate series structure
  522  *
  523  * This should be called for both legacy and MCS rates.
  524  *
  525  * This uses the rate series stuf from ath_tx_rate_fill_rcflags().
  526  *
  527  * It, along with ath_buf_set_rate, must be called -after- a burst
  528  * or aggregate is setup.
  529  */
  530 static void
  531 ath_rateseries_setup(struct ath_softc *sc, struct ieee80211_node *ni,
  532     struct ath_buf *bf, HAL_11N_RATE_SERIES *series)
  533 {
  534         struct ieee80211com *ic = ni->ni_ic;
  535         struct ath_hal *ah = sc->sc_ah;
  536         HAL_BOOL shortPreamble = AH_FALSE;
  537         const HAL_RATE_TABLE *rt = sc->sc_currates;
  538         int i;
  539         int pktlen;
  540         struct ath_rc_series *rc = bf->bf_state.bfs_rc;
  541 
  542         if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
  543             (ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_PREAMBLE))
  544                 shortPreamble = AH_TRUE;
  545 
  546         /*
  547          * If this is the first frame in an aggregate series,
  548          * use the aggregate length.
  549          */
  550         if (bf->bf_state.bfs_aggr)
  551                 pktlen = bf->bf_state.bfs_al;
  552         else
  553                 pktlen = bf->bf_state.bfs_pktlen;
  554 
  555         /*
  556          * XXX TODO: modify this routine to use the bfs_rc[x].flags
  557          * XXX fields.
  558          */
  559         memset(series, 0, sizeof(HAL_11N_RATE_SERIES) * 4);
  560         for (i = 0; i < ATH_RC_NUM;  i++) {
  561                 /* Only set flags for actual TX attempts */
  562                 if (rc[i].tries == 0)
  563                         continue;
  564 
  565                 series[i].Tries = rc[i].tries;
  566 
  567                 /*
  568                  * XXX TODO: When the NIC is capable of three stream TX,
  569                  * transmit 1/2 stream rates on two streams.
  570                  *
  571                  * This reduces the power consumption of the NIC and
  572                  * keeps it within the PCIe slot power limits.
  573                  */
  574                 series[i].ChSel = sc->sc_cur_txchainmask;
  575 
  576                 /*
  577                  * Setup rate and TX power cap for this series.
  578                  */
  579                 series[i].Rate = rt->info[rc[i].rix].rateCode;
  580                 series[i].RateIndex = rc[i].rix;
  581                 series[i].tx_power_cap = rc[i].tx_power_cap;
  582 
  583                 /*
  584                  * Enable RTS/CTS as appropriate.
  585                  */
  586                 if (rc[i].flags & ATH_RC_RTSCTS_FLAG)
  587                         series[i].RateFlags |= HAL_RATESERIES_RTS_CTS;
  588 
  589                 /*
  590                  * 11n rate? Update 11n flags.
  591                  */
  592                 if (rc[i].flags & ATH_RC_HT_FLAG) {
  593                         if (rc[i].flags & ATH_RC_CW40_FLAG)
  594                                 series[i].RateFlags |= HAL_RATESERIES_2040;
  595 
  596                         if (rc[i].flags & ATH_RC_SGI_FLAG)
  597                                 series[i].RateFlags |= HAL_RATESERIES_HALFGI;
  598 
  599                         if (rc[i].flags & ATH_RC_STBC_FLAG)
  600                                 series[i].RateFlags |= HAL_RATESERIES_STBC;
  601                 }
  602 
  603                 /*
  604                  * TODO: If we're all doing 11n rates then we can set LDPC.
  605                  * If we've been asked to /do/ LDPC but we are handed a
  606                  * legacy rate, then we should complain.  Loudly.
  607                  */
  608 
  609                 /*
  610                  * PktDuration doesn't include slot, ACK, RTS, etc timing -
  611                  * it's just the packet duration
  612                  */
  613                 if (rc[i].flags & ATH_RC_HT_FLAG) {
  614                         series[i].PktDuration =
  615                             ath_computedur_ht(pktlen
  616                                 , series[i].Rate
  617                                 , HT_RC_2_STREAMS(series[i].Rate)
  618                                 , series[i].RateFlags & HAL_RATESERIES_2040
  619                                 , series[i].RateFlags & HAL_RATESERIES_HALFGI);
  620                 } else {
  621                         if (shortPreamble)
  622                                 series[i].Rate |=
  623                                     rt->info[rc[i].rix].shortPreamble;
  624                         series[i].PktDuration = ath_hal_computetxtime(ah,
  625                             rt, pktlen, rc[i].rix, shortPreamble);
  626                 }
  627         }
  628 }
  629 
  630 #ifdef  ATH_DEBUG
  631 static void
  632 ath_rateseries_print(struct ath_softc *sc, HAL_11N_RATE_SERIES *series)
  633 {
  634         int i;
  635         for (i = 0; i < ATH_RC_NUM; i++) {
  636                 device_printf(sc->sc_dev ,"series %d: rate %x; tries %d; "
  637                     "pktDuration %d; chSel %d; txpowcap %d, rateFlags %x\n",
  638                     i,
  639                     series[i].Rate,
  640                     series[i].Tries,
  641                     series[i].PktDuration,
  642                     series[i].ChSel,
  643                     series[i].tx_power_cap,
  644                     series[i].RateFlags);
  645         }
  646 }
  647 #endif
  648 
  649 /*
  650  * Setup the 11n rate scenario and burst duration for the given TX descriptor
  651  * list.
  652  *
  653  * This isn't useful for sending beacon frames, which has different needs
  654  * wrt what's passed into the rate scenario function.
  655  */
  656 void
  657 ath_buf_set_rate(struct ath_softc *sc, struct ieee80211_node *ni,
  658     struct ath_buf *bf)
  659 {
  660         HAL_11N_RATE_SERIES series[4];
  661         struct ath_desc *ds = bf->bf_desc;
  662         struct ath_hal *ah = sc->sc_ah;
  663         int is_pspoll = (bf->bf_state.bfs_atype == HAL_PKT_TYPE_PSPOLL);
  664         int ctsrate = bf->bf_state.bfs_ctsrate;
  665         int flags = bf->bf_state.bfs_txflags;
  666 
  667         /* Setup rate scenario */
  668         memset(&series, 0, sizeof(series));
  669 
  670         ath_rateseries_setup(sc, ni, bf, series);
  671 
  672 #ifdef  ATH_DEBUG
  673         if (sc->sc_debug & ATH_DEBUG_XMIT)
  674                 ath_rateseries_print(sc, series);
  675 #endif
  676 
  677         /* Set rate scenario */
  678         /*
  679          * Note: Don't allow hardware to override the duration on
  680          * ps-poll packets.
  681          */
  682         ath_hal_set11nratescenario(ah, ds,
  683             !is_pspoll, /* whether to override the duration or not */
  684             ctsrate,    /* rts/cts rate */
  685             series,     /* 11n rate series */
  686             4,          /* number of series */
  687             flags);
  688 
  689         /* Set burst duration */
  690         /*
  691          * This is only required when doing 11n burst, not aggregation
  692          * ie, if there's a second frame in a RIFS or A-MPDU burst
  693          * w/ >1 A-MPDU frame bursting back to back.
  694          * Normal A-MPDU doesn't do bursting -between- aggregates.
  695          *
  696          * .. and it's highly likely this won't ever be implemented
  697          */
  698         //ath_hal_set11nburstduration(ah, ds, 8192);
  699 }
  700 
  701 /*
  702  * Form an aggregate packet list.
  703  *
  704  * This function enforces the aggregate restrictions/requirements.
  705  *
  706  * These are:
  707  *
  708  * + The aggregate size maximum (64k for AR9160 and later, 8K for
  709  *   AR5416 when doing RTS frame protection.)
  710  * + Maximum number of sub-frames for an aggregate
  711  * + The aggregate delimiter size, giving MACs time to do whatever is
  712  *   needed before each frame
  713  * + Enforce the BAW limit
  714  *
  715  * Each descriptor queued should have the DMA setup.
  716  * The rate series, descriptor setup, linking, etc is all done
  717  * externally. This routine simply chains them together.
  718  * ath_tx_setds_11n() will take care of configuring the per-
  719  * descriptor setup, and ath_buf_set_rate() will configure the
  720  * rate control.
  721  *
  722  * The TID lock is required for the entirety of this function.
  723  *
  724  * If some code in another thread adds to the head of this
  725  * list, very strange behaviour will occur. Since retransmission is the
  726  * only reason this will occur, and this routine is designed to be called
  727  * from within the scheduler task, it won't ever clash with the completion
  728  * task.
  729  *
  730  * So if you want to call this from an upper layer context (eg, to direct-
  731  * dispatch aggregate frames to the hardware), please keep this in mind.
  732  */
  733 ATH_AGGR_STATUS
  734 ath_tx_form_aggr(struct ath_softc *sc, struct ath_node *an,
  735     struct ath_tid *tid, ath_bufhead *bf_q)
  736 {
  737         //struct ieee80211_node *ni = &an->an_node;
  738         struct ath_buf *bf, *bf_first = NULL, *bf_prev = NULL;
  739         int nframes = 0;
  740         uint16_t aggr_limit = 0, al = 0, bpad = 0, al_delta, h_baw;
  741         struct ieee80211_tx_ampdu *tap;
  742         int status = ATH_AGGR_DONE;
  743         int prev_frames = 0;    /* XXX for AR5416 burst, not done here */
  744         int prev_al = 0;        /* XXX also for AR5416 burst */
  745 
  746         ATH_TX_LOCK_ASSERT(sc);
  747 
  748         tap = ath_tx_get_tx_tid(an, tid->tid);
  749         if (tap == NULL) {
  750                 status = ATH_AGGR_ERROR;
  751                 goto finish;
  752         }
  753 
  754         h_baw = tap->txa_wnd / 2;
  755 
  756         for (;;) {
  757                 bf = ATH_TID_FIRST(tid);
  758                 if (bf_first == NULL)
  759                         bf_first = bf;
  760                 if (bf == NULL) {
  761                         status = ATH_AGGR_DONE;
  762                         break;
  763                 } else {
  764                         /*
  765                          * It's the first frame;
  766                          * set the aggregation limit based on the
  767                          * rate control decision that has been made.
  768                          */
  769                         aggr_limit = ath_get_aggr_limit(sc, bf_first);
  770                 }
  771 
  772                 /* Set this early just so things don't get confused */
  773                 bf->bf_next = NULL;
  774 
  775                 /*
  776                  * If the frame doesn't have a sequence number that we're
  777                  * tracking in the BAW (eg NULL QOS data frame), we can't
  778                  * aggregate it. Stop the aggregation process; the sender
  779                  * can then TX what's in the list thus far and then
  780                  * TX the frame individually.
  781                  */
  782                 if (! bf->bf_state.bfs_dobaw) {
  783                         status = ATH_AGGR_NONAGGR;
  784                         break;
  785                 }
  786 
  787                 /*
  788                  * If any of the rates are non-HT, this packet
  789                  * can't be aggregated.
  790                  * XXX TODO: add a bf_state flag which gets marked
  791                  * if any active rate is non-HT.
  792                  */
  793 
  794                 /*
  795                  * do not exceed aggregation limit
  796                  */
  797                 al_delta = ATH_AGGR_DELIM_SZ + bf->bf_state.bfs_pktlen;
  798                 if (nframes &&
  799                     (aggr_limit < (al + bpad + al_delta + prev_al))) {
  800                         status = ATH_AGGR_LIMITED;
  801                         break;
  802                 }
  803 
  804                 /*
  805                  * If RTS/CTS is set on the first frame, enforce
  806                  * the RTS aggregate limit.
  807                  */
  808                 if (bf_first->bf_state.bfs_txflags &
  809                     (HAL_TXDESC_CTSENA | HAL_TXDESC_RTSENA)) {
  810                         if (nframes &&
  811                            (sc->sc_rts_aggr_limit <
  812                              (al + bpad + al_delta + prev_al))) {
  813                                 status = ATH_AGGR_8K_LIMITED;
  814                                 break;
  815                         }
  816                 }
  817 
  818                 /*
  819                  * Do not exceed subframe limit.
  820                  */
  821                 if ((nframes + prev_frames) >= MIN((h_baw),
  822                     IEEE80211_AMPDU_SUBFRAME_DEFAULT)) {
  823                         status = ATH_AGGR_LIMITED;
  824                         break;
  825                 }
  826 
  827                 /*
  828                  * If the current frame has an RTS/CTS configuration
  829                  * that differs from the first frame, override the
  830                  * subsequent frame with this config.
  831                  */
  832                 if (bf != bf_first) {
  833                         bf->bf_state.bfs_txflags &=
  834                             ~ (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
  835                         bf->bf_state.bfs_txflags |=
  836                             bf_first->bf_state.bfs_txflags &
  837                             (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
  838                 }
  839 
  840                 /*
  841                  * If the packet has a sequence number, do not
  842                  * step outside of the block-ack window.
  843                  */
  844                 if (! BAW_WITHIN(tap->txa_start, tap->txa_wnd,
  845                     SEQNO(bf->bf_state.bfs_seqno))) {
  846                         status = ATH_AGGR_BAW_CLOSED;
  847                         break;
  848                 }
  849 
  850                 /*
  851                  * this packet is part of an aggregate.
  852                  */
  853                 ATH_TID_REMOVE(tid, bf, bf_list);
  854 
  855                 /* The TID lock is required for the BAW update */
  856                 ath_tx_addto_baw(sc, an, tid, bf);
  857                 bf->bf_state.bfs_addedbaw = 1;
  858 
  859                 /*
  860                  * XXX enforce ACK for aggregate frames (this needs to be
  861                  * XXX handled more gracefully?
  862                  */
  863                 if (bf->bf_state.bfs_txflags & HAL_TXDESC_NOACK) {
  864                         device_printf(sc->sc_dev,
  865                             "%s: HAL_TXDESC_NOACK set for an aggregate frame?\n",
  866                             __func__);
  867                         bf->bf_state.bfs_txflags &= (~HAL_TXDESC_NOACK);
  868                 }
  869 
  870                 /*
  871                  * Add the now owned buffer (which isn't
  872                  * on the software TXQ any longer) to our
  873                  * aggregate frame list.
  874                  */
  875                 TAILQ_INSERT_TAIL(bf_q, bf, bf_list);
  876                 nframes ++;
  877 
  878                 /* Completion handler */
  879                 bf->bf_comp = ath_tx_aggr_comp;
  880 
  881                 /*
  882                  * add padding for previous frame to aggregation length
  883                  */
  884                 al += bpad + al_delta;
  885 
  886                 /*
  887                  * Calculate delimiters needed for the current frame
  888                  */
  889                 bf->bf_state.bfs_ndelim =
  890                     ath_compute_num_delims(sc, bf_first,
  891                     bf->bf_state.bfs_pktlen);
  892 
  893                 /*
  894                  * Calculate the padding needed from this set of delimiters,
  895                  * used when calculating if the next frame will fit in
  896                  * the aggregate.
  897                  */
  898                 bpad = PADBYTES(al_delta) + (bf->bf_state.bfs_ndelim << 2);
  899 
  900                 /*
  901                  * Chain the buffers together
  902                  */
  903                 if (bf_prev)
  904                         bf_prev->bf_next = bf;
  905                 bf_prev = bf;
  906 
  907                 /*
  908                  * If we're leaking frames, just return at this point;
  909                  * we've queued a single frame and we don't want to add
  910                  * any more.
  911                  */
  912                 if (tid->an->an_leak_count) {
  913                         status = ATH_AGGR_LEAK_CLOSED;
  914                         break;
  915                 }
  916 
  917 #if 0
  918                 /*
  919                  * terminate aggregation on a small packet boundary
  920                  */
  921                 if (bf->bf_state.bfs_pktlen < ATH_AGGR_MINPLEN) {
  922                         status = ATH_AGGR_SHORTPKT;
  923                         break;
  924                 }
  925 #endif
  926 
  927         }
  928 
  929 finish:
  930         /*
  931          * Just in case the list was empty when we tried to
  932          * dequeue a packet ..
  933          */
  934         if (bf_first) {
  935                 bf_first->bf_state.bfs_al = al;
  936                 bf_first->bf_state.bfs_nframes = nframes;
  937         }
  938         return status;
  939 }

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