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

   1/*
   2 * Copyright (c) 2008-2011 Atheros Communications Inc.
   3 * Copyright (c) 2011 Neratec Solutions AG
   4 *
   5 * Permission to use, copy, modify, and/or distribute this software for any
   6 * purpose with or without fee is hereby granted, provided that the above
   7 * copyright notice and this permission notice appear in all copies.
   8 *
   9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16 */
  17
  18#include "hw.h"
  19#include "hw-ops.h"
  20#include "ath9k.h"
  21#include "dfs.h"
  22#include "dfs_debug.h"
  23
  24/* internal struct to pass radar data */
  25struct ath_radar_data {
  26        u8 pulse_bw_info;
  27        u8 rssi;
  28        u8 ext_rssi;
  29        u8 pulse_length_ext;
  30        u8 pulse_length_pri;
  31};
  32
  33/* convert pulse duration to usecs, considering clock mode */
  34static u32 dur_to_usecs(struct ath_hw *ah, u32 dur)
  35{
  36        const u32 AR93X_NSECS_PER_DUR = 800;
  37        const u32 AR93X_NSECS_PER_DUR_FAST = (8000 / 11);
  38        u32 nsecs;
  39
  40        if (IS_CHAN_A_FAST_CLOCK(ah, ah->curchan))
  41                nsecs = dur * AR93X_NSECS_PER_DUR_FAST;
  42        else
  43                nsecs = dur * AR93X_NSECS_PER_DUR;
  44
  45        return (nsecs + 500) / 1000;
  46}
  47
  48#define PRI_CH_RADAR_FOUND 0x01
  49#define EXT_CH_RADAR_FOUND 0x02
  50static bool
  51ath9k_postprocess_radar_event(struct ath_softc *sc,
  52                              struct ath_radar_data *ard,
  53                              struct pulse_event *pe)
  54{
  55        u8 rssi;
  56        u16 dur;
  57
  58        /*
  59         * Only the last 2 bits of the BW info are relevant, they indicate
  60         * which channel the radar was detected in.
  61         */
  62        ard->pulse_bw_info &= 0x03;
  63
  64        switch (ard->pulse_bw_info) {
  65        case PRI_CH_RADAR_FOUND:
  66                /* radar in ctrl channel */
  67                dur = ard->pulse_length_pri;
  68                DFS_STAT_INC(sc, pri_phy_errors);
  69                /*
  70                 * cannot use ctrl channel RSSI
  71                 * if extension channel is stronger
  72                 */
  73                rssi = (ard->ext_rssi >= (ard->rssi + 3)) ? 0 : ard->rssi;
  74                break;
  75        case EXT_CH_RADAR_FOUND:
  76                /* radar in extension channel */
  77                dur = ard->pulse_length_ext;
  78                DFS_STAT_INC(sc, ext_phy_errors);
  79                /*
  80                 * cannot use extension channel RSSI
  81                 * if control channel is stronger
  82                 */
  83                rssi = (ard->rssi >= (ard->ext_rssi + 12)) ? 0 : ard->ext_rssi;
  84                break;
  85        case (PRI_CH_RADAR_FOUND | EXT_CH_RADAR_FOUND):
  86                /*
  87                 * Conducted testing, when pulse is on DC, both pri and ext
  88                 * durations are reported to be same
  89                 *
  90                 * Radiated testing, when pulse is on DC, different pri and
  91                 * ext durations are reported, so take the larger of the two
  92                 */
  93                if (ard->pulse_length_ext >= ard->pulse_length_pri)
  94                        dur = ard->pulse_length_ext;
  95                else
  96                        dur = ard->pulse_length_pri;
  97                DFS_STAT_INC(sc, dc_phy_errors);
  98
  99                /* when both are present use stronger one */
 100                rssi = (ard->rssi < ard->ext_rssi) ? ard->ext_rssi : ard->rssi;
 101                break;
 102        default:
 103                /*
 104                 * Bogus bandwidth info was received in descriptor,
 105                 * so ignore this PHY error
 106                 */
 107                DFS_STAT_INC(sc, bwinfo_discards);
 108                return false;
 109        }
 110
 111        if (rssi == 0) {
 112                DFS_STAT_INC(sc, rssi_discards);
 113                return false;
 114        }
 115
 116        /*
 117         * TODO: check chirping pulses
 118         *       checks for chirping are dependent on the DFS regulatory domain
 119         *       used, which is yet TBD
 120         */
 121
 122        /* convert duration to usecs */
 123        pe->width = dur_to_usecs(sc->sc_ah, dur);
 124        pe->rssi = rssi;
 125
 126        DFS_STAT_INC(sc, pulses_detected);
 127        return true;
 128}
 129#undef PRI_CH_RADAR_FOUND
 130#undef EXT_CH_RADAR_FOUND
 131
 132/*
 133 * DFS: check PHY-error for radar pulse and feed the detector
 134 */
 135void ath9k_dfs_process_phyerr(struct ath_softc *sc, void *data,
 136                              struct ath_rx_status *rs, u64 mactime)
 137{
 138        struct ath_radar_data ard;
 139        u16 datalen;
 140        char *vdata_end;
 141        struct pulse_event pe;
 142        struct ath_hw *ah = sc->sc_ah;
 143        struct ath_common *common = ath9k_hw_common(ah);
 144
 145        DFS_STAT_INC(sc, pulses_total);
 146        if ((rs->rs_phyerr != ATH9K_PHYERR_RADAR) &&
 147            (rs->rs_phyerr != ATH9K_PHYERR_FALSE_RADAR_EXT)) {
 148                ath_dbg(common, DFS,
 149                        "Error: rs_phyer=0x%x not a radar error\n",
 150                        rs->rs_phyerr);
 151                DFS_STAT_INC(sc, pulses_no_dfs);
 152                return;
 153        }
 154
 155        datalen = rs->rs_datalen;
 156        if (datalen == 0) {
 157                DFS_STAT_INC(sc, datalen_discards);
 158                return;
 159        }
 160
 161        ard.rssi = rs->rs_rssi_ctl0;
 162        ard.ext_rssi = rs->rs_rssi_ext0;
 163
 164        /*
 165         * hardware stores this as 8 bit signed value.
 166         * we will cap it at 0 if it is a negative number
 167         */
 168        if (ard.rssi & 0x80)
 169                ard.rssi = 0;
 170        if (ard.ext_rssi & 0x80)
 171                ard.ext_rssi = 0;
 172
 173        vdata_end = (char *)data + datalen;
 174        ard.pulse_bw_info = vdata_end[-1];
 175        ard.pulse_length_ext = vdata_end[-2];
 176        ard.pulse_length_pri = vdata_end[-3];
 177        pe.freq = ah->curchan->channel;
 178        pe.ts = mactime;
 179        if (ath9k_postprocess_radar_event(sc, &ard, &pe)) {
 180                struct dfs_pattern_detector *pd = sc->dfs_detector;
 181                static u64 last_ts;
 182                ath_dbg(common, DFS,
 183                        "ath9k_dfs_process_phyerr: channel=%d, ts=%llu, "
 184                        "width=%d, rssi=%d, delta_ts=%llu\n",
 185                        pe.freq, pe.ts, pe.width, pe.rssi, pe.ts-last_ts);
 186                last_ts = pe.ts;
 187                DFS_STAT_INC(sc, pulses_processed);
 188                if (pd != NULL && pd->add_pulse(pd, &pe)) {
 189                        DFS_STAT_INC(sc, radar_detected);
 190                        ieee80211_radar_detected(sc->hw);
 191                }
 192        }
 193}
 194