drivers/net/wireless/ath/ath9k/common-beacon.c

   1 /*
   2  * Copyright (c) 2008-2011 Atheros Communications Inc.
   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 "common.h"
  18
  19 #define FUDGE 2
  20
  21 static u32 ath9k_get_next_tbtt(struct ath_hw *ah, u64 tsf,
  22                                unsigned int interval)
  23 {
  24         unsigned int offset, divisor;
  25
  26         tsf += TU_TO_USEC(FUDGE + ah->config.sw_beacon_response_time);
  27         divisor = TU_TO_USEC(interval);
  28         div_u64_rem(tsf, divisor, &offset);
  29
  30         return (u32) tsf + divisor - offset;
  31 }
  32
  33 /*
  34  * This sets up the beacon timers according to the timestamp of the last
  35  * received beacon and the current TSF, configures PCF and DTIM
  36  * handling, programs the sleep registers so the hardware will wakeup in
  37  * time to receive beacons, and configures the beacon miss handling so
  38  * we'll receive a BMISS interrupt when we stop seeing beacons from the AP
  39  * we've associated with.
  40  */
  41 int ath9k_cmn_beacon_config_sta(struct ath_hw *ah,
  42                                  struct ath_beacon_config *conf,
  43                                  struct ath9k_beacon_state *bs)
  44 {
  45         struct ath_common *common = ath9k_hw_common(ah);
  46         int dtim_intval;
  47         u64 tsf;
  48
  49         /* No need to configure beacon if we are not associated */
  50         if (!test_bit(ATH_OP_PRIM_STA_VIF, &common->op_flags)) {
  51                 ath_dbg(common, BEACON,
  52                         "STA is not yet associated..skipping beacon config\n");
  53                 return -EPERM;
  54         }
  55
  56         memset(bs, 0, sizeof(*bs));
  57         conf->intval = conf->beacon_interval;
  58
  59         /*
  60          * Setup dtim parameters according to
  61          * last beacon we received (which may be none).
  62          */
  63         dtim_intval = conf->intval * conf->dtim_period;
  64
  65         /*
  66          * Pull nexttbtt forward to reflect the current
  67          * TSF and calculate dtim state for the result.
  68          */
  69         tsf = ath9k_hw_gettsf64(ah);
  70         conf->nexttbtt = ath9k_get_next_tbtt(ah, tsf, conf->intval);
  71
  72         bs->bs_intval = TU_TO_USEC(conf->intval);
  73         bs->bs_dtimperiod = conf->dtim_period * bs->bs_intval;
  74         bs->bs_nexttbtt = conf->nexttbtt;
  75         bs->bs_nextdtim = conf->nexttbtt;
  76         if (conf->dtim_period > 1)
  77                 bs->bs_nextdtim = ath9k_get_next_tbtt(ah, tsf, dtim_intval);
  78
  79         /*
  80          * Calculate the number of consecutive beacons to miss* before taking
  81          * a BMISS interrupt. The configuration is specified in TU so we only
  82          * need calculate based on the beacon interval.  Note that we clamp the
  83          * result to at most 15 beacons.
  84          */
  85         bs->bs_bmissthreshold = DIV_ROUND_UP(conf->bmiss_timeout, conf->intval);
  86         if (bs->bs_bmissthreshold > 15)
  87                 bs->bs_bmissthreshold = 15;
  88         else if (bs->bs_bmissthreshold <= 0)
  89                 bs->bs_bmissthreshold = 1;
  90
  91         /*
  92          * Calculate sleep duration. The configuration is given in ms.
  93          * We ensure a multiple of the beacon period is used. Also, if the sleep
  94          * duration is greater than the DTIM period then it makes senses
  95          * to make it a multiple of that.
  96          *
  97          * XXX fixed at 100ms
  98          */
  99
 100         bs->bs_sleepduration = TU_TO_USEC(roundup(IEEE80211_MS_TO_TU(100),
 101                                                   conf->intval));
 102         if (bs->bs_sleepduration > bs->bs_dtimperiod)
 103                 bs->bs_sleepduration = bs->bs_dtimperiod;
 104
 105         /* TSF out of range threshold fixed at 1 second */
 106         bs->bs_tsfoor_threshold = ATH9K_TSFOOR_THRESHOLD;
 107
 108         ath_dbg(common, BEACON, "bmiss: %u sleep: %u\n",
 109                 bs->bs_bmissthreshold, bs->bs_sleepduration);
 110         return 0;
 111 }
 112 EXPORT_SYMBOL(ath9k_cmn_beacon_config_sta);
 113
 114 void ath9k_cmn_beacon_config_adhoc(struct ath_hw *ah,
 115                                    struct ath_beacon_config *conf)
 116 {
 117         struct ath_common *common = ath9k_hw_common(ah);
 118
 119         conf->intval = TU_TO_USEC(conf->beacon_interval);
 120
 121         if (conf->ibss_creator)
 122                 conf->nexttbtt = conf->intval;
 123         else
 124                 conf->nexttbtt = ath9k_get_next_tbtt(ah, ath9k_hw_gettsf64(ah),
 125                                                conf->beacon_interval);
 126
 127         if (conf->enable_beacon)
 128                 ah->imask |= ATH9K_INT_SWBA;
 129         else
 130                 ah->imask &= ~ATH9K_INT_SWBA;
 131
 132         ath_dbg(common, BEACON,
 133                 "IBSS (%s) nexttbtt: %u intval: %u conf_intval: %u\n",
 134                 (conf->enable_beacon) ? "Enable" : "Disable",
 135                 conf->nexttbtt, conf->intval, conf->beacon_interval);
 136 }
 137 EXPORT_SYMBOL(ath9k_cmn_beacon_config_adhoc);
 138
 139 /*
 140  * For multi-bss ap support beacons are either staggered evenly over N slots or
 141  * burst together.  For the former arrange for the SWBA to be delivered for each
 142  * slot. Slots that are not occupied will generate nothing.
 143  */
 144 void ath9k_cmn_beacon_config_ap(struct ath_hw *ah,
 145                                 struct ath_beacon_config *conf,
 146                                 unsigned int bc_buf)
 147 {
 148         struct ath_common *common = ath9k_hw_common(ah);
 149
 150         /* NB: the beacon interval is kept internally in TU's */
 151         conf->intval = TU_TO_USEC(conf->beacon_interval);
 152         conf->intval /= bc_buf;
 153         conf->nexttbtt = ath9k_get_next_tbtt(ah, ath9k_hw_gettsf64(ah),
 154                                        conf->beacon_interval);
 155
 156         if (conf->enable_beacon)
 157                 ah->imask |= ATH9K_INT_SWBA;
 158         else
 159                 ah->imask &= ~ATH9K_INT_SWBA;
 160
 161         ath_dbg(common, BEACON,
 162                 "AP (%s) nexttbtt: %u intval: %u conf_intval: %u\n",
 163                 (conf->enable_beacon) ? "Enable" : "Disable",
 164                 conf->nexttbtt, conf->intval, conf->beacon_interval);
 165 }
 166 EXPORT_SYMBOL(ath9k_cmn_beacon_config_ap);