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 /*
  25  * TODO: move into or synchronize this with generic header
  26  *       as soon as IF is defined
  27  */
  28 struct dfs_radar_pulse {
  29         u16 freq;
  30         u64 ts;
  31         u32 width;
  32         u8 rssi;
  33 };
  34
  35 /* internal struct to pass radar data */
  36 struct ath_radar_data {
  37         u8 pulse_bw_info;
  38         u8 rssi;
  39         u8 ext_rssi;
  40         u8 pulse_length_ext;
  41         u8 pulse_length_pri;
  42 };
  43
  44 /* convert pulse duration to usecs, considering clock mode */
  45 static u32 dur_to_usecs(struct ath_hw *ah, u32 dur)
  46 {
  47         const u32 AR93X_NSECS_PER_DUR = 800;
  48         const u32 AR93X_NSECS_PER_DUR_FAST = (8000 / 11);
  49         u32 nsecs;
  50
  51         if (IS_CHAN_A_FAST_CLOCK(ah, ah->curchan))
  52                 nsecs = dur * AR93X_NSECS_PER_DUR_FAST;
  53         else
  54                 nsecs = dur * AR93X_NSECS_PER_DUR;
  55
  56         return (nsecs + 500) / 1000;
  57 }
  58
  59 #define PRI_CH_RADAR_FOUND 0x01
  60 #define EXT_CH_RADAR_FOUND 0x02
  61 static bool
  62 ath9k_postprocess_radar_event(struct ath_softc *sc,
  63                               struct ath_radar_data *are,
  64                               struct dfs_radar_pulse *drp)
  65 {
  66         u8 rssi;
  67         u16 dur;
  68
  69         ath_dbg(ath9k_hw_common(sc->sc_ah), DFS,
  70                 "pulse_bw_info=0x%x, pri,ext len/rssi=(%u/%u, %u/%u)\n",
  71                 are->pulse_bw_info,
  72                 are->pulse_length_pri, are->rssi,
  73                 are->pulse_length_ext, are->ext_rssi);
  74
  75         /*
  76          * Only the last 2 bits of the BW info are relevant, they indicate
  77          * which channel the radar was detected in.
  78          */
  79         are->pulse_bw_info &= 0x03;
  80
  81         switch (are->pulse_bw_info) {
  82         case PRI_CH_RADAR_FOUND:
  83                 /* radar in ctrl channel */
  84                 dur = are->pulse_length_pri;
  85                 DFS_STAT_INC(sc, pri_phy_errors);
  86                 /*
  87                  * cannot use ctrl channel RSSI
  88                  * if extension channel is stronger
  89                  */
  90                 rssi = (are->ext_rssi >= (are->rssi + 3)) ? 0 : are->rssi;
  91                 break;
  92         case EXT_CH_RADAR_FOUND:
  93                 /* radar in extension channel */
  94                 dur = are->pulse_length_ext;
  95                 DFS_STAT_INC(sc, ext_phy_errors);
  96                 /*
  97                  * cannot use extension channel RSSI
  98                  * if control channel is stronger
  99                  */
 100                 rssi = (are->rssi >= (are->ext_rssi + 12)) ? 0 : are->ext_rssi;
 101                 break;
 102         case (PRI_CH_RADAR_FOUND | EXT_CH_RADAR_FOUND):
 103                 /*
 104                  * Conducted testing, when pulse is on DC, both pri and ext
 105                  * durations are reported to be same
 106                  *
 107                  * Radiated testing, when pulse is on DC, different pri and
 108                  * ext durations are reported, so take the larger of the two
 109                  */
 110                 if (are->pulse_length_ext >= are->pulse_length_pri)
 111                         dur = are->pulse_length_ext;
 112                 else
 113                         dur = are->pulse_length_pri;
 114                 DFS_STAT_INC(sc, dc_phy_errors);
 115
 116                 /* when both are present use stronger one */
 117                 rssi = (are->rssi < are->ext_rssi) ? are->ext_rssi : are->rssi;
 118                 break;
 119         default:
 120                 /*
 121                  * Bogus bandwidth info was received in descriptor,
 122                  * so ignore this PHY error
 123                  */
 124                 DFS_STAT_INC(sc, bwinfo_discards);
 125                 return false;
 126         }
 127
 128         if (rssi == 0) {
 129                 DFS_STAT_INC(sc, rssi_discards);
 130                 return false;
 131         }
 132
 133         /*
 134          * TODO: check chirping pulses
 135          *       checks for chirping are dependent on the DFS regulatory domain
 136          *       used, which is yet TBD
 137          */
 138
 139         /* convert duration to usecs */
 140         drp->width = dur_to_usecs(sc->sc_ah, dur);
 141         drp->rssi = rssi;
 142
 143         DFS_STAT_INC(sc, pulses_detected);
 144         return true;
 145 }
 146 #undef PRI_CH_RADAR_FOUND
 147 #undef EXT_CH_RADAR_FOUND
 148
 149 /*
 150  * DFS: check PHY-error for radar pulse and feed the detector
 151  */
 152 void ath9k_dfs_process_phyerr(struct ath_softc *sc, void *data,
 153                               struct ath_rx_status *rs, u64 mactime)
 154 {
 155         struct ath_radar_data ard;
 156         u16 datalen;
 157         char *vdata_end;
 158         struct dfs_radar_pulse drp;
 159         struct ath_hw *ah = sc->sc_ah;
 160         struct ath_common *common = ath9k_hw_common(ah);
 161
 162         if ((!(rs->rs_phyerr != ATH9K_PHYERR_RADAR)) &&
 163             (!(rs->rs_phyerr != ATH9K_PHYERR_FALSE_RADAR_EXT))) {
 164                 ath_dbg(common, DFS,
 165                         "Error: rs_phyer=0x%x not a radar error\n",
 166                         rs->rs_phyerr);
 167                 return;
 168         }
 169
 170         datalen = rs->rs_datalen;
 171         if (datalen == 0) {
 172                 DFS_STAT_INC(sc, datalen_discards);
 173                 return;
 174         }
 175
 176         ard.rssi = rs->rs_rssi_ctl0;
 177         ard.ext_rssi = rs->rs_rssi_ext0;
 178
 179         /*
 180          * hardware stores this as 8 bit signed value.
 181          * we will cap it at 0 if it is a negative number
 182          */
 183         if (ard.rssi & 0x80)
 184                 ard.rssi = 0;
 185         if (ard.ext_rssi & 0x80)
 186                 ard.ext_rssi = 0;
 187
 188         vdata_end = (char *)data + datalen;
 189         ard.pulse_bw_info = vdata_end[-1];
 190         ard.pulse_length_ext = vdata_end[-2];
 191         ard.pulse_length_pri = vdata_end[-3];
 192
 193         ath_dbg(common, DFS,
 194                 "bw_info=%d, length_pri=%d, length_ext=%d, "
 195                 "rssi_pri=%d, rssi_ext=%d\n",
 196                 ard.pulse_bw_info, ard.pulse_length_pri, ard.pulse_length_ext,
 197                 ard.rssi, ard.ext_rssi);
 198
 199         drp.freq = ah->curchan->channel;
 200         drp.ts = mactime;
 201         if (ath9k_postprocess_radar_event(sc, &ard, &drp)) {
 202                 static u64 last_ts;
 203                 ath_dbg(common, DFS,
 204                         "ath9k_dfs_process_phyerr: channel=%d, ts=%llu, "
 205                         "width=%d, rssi=%d, delta_ts=%llu\n",
 206                         drp.freq, drp.ts, drp.width, drp.rssi, drp.ts-last_ts);
 207                 last_ts = drp.ts;
 208                 /*
 209                  * TODO: forward pulse to pattern detector
 210                  *
 211                  * ieee80211_add_radar_pulse(drp.freq, drp.ts,
 212                  *                           drp.width, drp.rssi);
 213                  */
 214         }
 215 }