LXR linux/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
  21static 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 */
  41int 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}
 112EXPORT_SYMBOL(ath9k_cmn_beacon_config_sta);
 113
 114void 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}
 137EXPORT_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 */
 144void 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}
 166EXPORT_SYMBOL(ath9k_cmn_beacon_config_ap);
 167