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1/*2 * Copyright (c) 2008-2011 Atheros Communications Inc.3 * Copyright (c) 2011 Neratec Solutions AG4 *5 * Permission to use, copy, modify, and/or distribute this software for any6 * purpose with or without fee is hereby granted, provided that the above7 * copyright notice and this permission notice appear in all copies.8 *9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF15 * 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/**** begin: CHIRP ************************************************************/34 35/* min and max gradients for defined FCC chirping pulses, given by36 * - 20MHz chirp width over a pulse width of 50us37 * - 5MHz chirp width over a pulse width of 100us38 */39static const int BIN_DELTA_MIN = 1;40static const int BIN_DELTA_MAX = 10;41 42/* we need at least 3 deltas / 4 samples for a reliable chirp detection */43#define NUM_DIFFS 344#define FFT_NUM_SAMPLES (NUM_DIFFS + 1)45 46/* Threshold for difference of delta peaks */47static const int MAX_DIFF = 2;48 49/* width range to be checked for chirping */50static const int MIN_CHIRP_PULSE_WIDTH = 20;51static const int MAX_CHIRP_PULSE_WIDTH = 110;52 53struct ath9k_dfs_fft_20 {54 u8 bin[28];55 u8 lower_bins[3];56} __packed;57struct ath9k_dfs_fft_40 {58 u8 bin[64];59 u8 lower_bins[3];60 u8 upper_bins[3];61} __packed;62 63static inline int fft_max_index(u8 *bins)64{65 return (bins[2] & 0xfc) >> 2;66}67static inline int fft_max_magnitude(u8 *bins)68{69 return (bins[0] & 0xc0) >> 6 | bins[1] << 2 | (bins[2] & 0x03) << 10;70}71static inline u8 fft_bitmap_weight(u8 *bins)72{73 return bins[0] & 0x3f;74}75 76static int ath9k_get_max_index_ht40(struct ath9k_dfs_fft_40 *fft,77 bool is_ctl, bool is_ext)78{79 const int DFS_UPPER_BIN_OFFSET = 64;80 /* if detected radar on both channels, select the significant one */81 if (is_ctl && is_ext) {82 /* first check wether channels have 'strong' bins */83 is_ctl = fft_bitmap_weight(fft->lower_bins) != 0;84 is_ext = fft_bitmap_weight(fft->upper_bins) != 0;85 86 /* if still unclear, take higher magnitude */87 if (is_ctl && is_ext) {88 int mag_lower = fft_max_magnitude(fft->lower_bins);89 int mag_upper = fft_max_magnitude(fft->upper_bins);90 if (mag_upper > mag_lower)91 is_ctl = false;92 else93 is_ext = false;94 }95 }96 if (is_ctl)97 return fft_max_index(fft->lower_bins);98 return fft_max_index(fft->upper_bins) + DFS_UPPER_BIN_OFFSET;99}100static bool ath9k_check_chirping(struct ath_softc *sc, u8 *data,101 int datalen, bool is_ctl, bool is_ext)102{103 int i;104 int max_bin[FFT_NUM_SAMPLES];105 struct ath_hw *ah = sc->sc_ah;106 struct ath_common *common = ath9k_hw_common(ah);107 int prev_delta;108 109 if (IS_CHAN_HT40(ah->curchan)) {110 struct ath9k_dfs_fft_40 *fft = (struct ath9k_dfs_fft_40 *) data;111 int num_fft_packets = datalen / sizeof(*fft);112 if (num_fft_packets == 0)113 return false;114 115 ath_dbg(common, DFS, "HT40: datalen=%d, num_fft_packets=%d\n",116 datalen, num_fft_packets);117 if (num_fft_packets < FFT_NUM_SAMPLES) {118 ath_dbg(common, DFS, "not enough packets for chirp\n");119 return false;120 }121 /* HW sometimes adds 2 garbage bytes in front of FFT samples */122 if ((datalen % sizeof(*fft)) == 2) {123 fft = (struct ath9k_dfs_fft_40 *) (data + 2);124 ath_dbg(common, DFS, "fixing datalen by 2\n");125 }126 if (IS_CHAN_HT40MINUS(ah->curchan))127 swap(is_ctl, is_ext);128 129 for (i = 0; i < FFT_NUM_SAMPLES; i++)130 max_bin[i] = ath9k_get_max_index_ht40(fft + i, is_ctl,131 is_ext);132 } else {133 struct ath9k_dfs_fft_20 *fft = (struct ath9k_dfs_fft_20 *) data;134 int num_fft_packets = datalen / sizeof(*fft);135 if (num_fft_packets == 0)136 return false;137 ath_dbg(common, DFS, "HT20: datalen=%d, num_fft_packets=%d\n",138 datalen, num_fft_packets);139 if (num_fft_packets < FFT_NUM_SAMPLES) {140 ath_dbg(common, DFS, "not enough packets for chirp\n");141 return false;142 }143 /* in ht20, this is a 6-bit signed number => shift it to 0 */144 for (i = 0; i < FFT_NUM_SAMPLES; i++)145 max_bin[i] = fft_max_index(fft[i].lower_bins) ^ 0x20;146 }147 ath_dbg(common, DFS, "bin_max = [%d, %d, %d, %d]\n",148 max_bin[0], max_bin[1], max_bin[2], max_bin[3]);149 150 /* Check for chirp attributes within specs151 * a) delta of adjacent max_bins is within range152 * b) delta of adjacent deltas are within tolerance153 */154 prev_delta = 0;155 for (i = 0; i < NUM_DIFFS; i++) {156 int ddelta = -1;157 int delta = max_bin[i + 1] - max_bin[i];158 159 /* ensure gradient is within valid range */160 if (abs(delta) < BIN_DELTA_MIN || abs(delta) > BIN_DELTA_MAX) {161 ath_dbg(common, DFS, "CHIRP: invalid delta %d "162 "in sample %d\n", delta, i);163 return false;164 }165 if (i == 0)166 goto done;167 ddelta = delta - prev_delta;168 if (abs(ddelta) > MAX_DIFF) {169 ath_dbg(common, DFS, "CHIRP: ddelta %d too high\n",170 ddelta);171 return false;172 }173done:174 ath_dbg(common, DFS, "CHIRP - %d: delta=%d, ddelta=%d\n",175 i, delta, ddelta);176 prev_delta = delta;177 }178 return true;179}180/**** end: CHIRP **************************************************************/181 182/* convert pulse duration to usecs, considering clock mode */183static u32 dur_to_usecs(struct ath_hw *ah, u32 dur)184{185 const u32 AR93X_NSECS_PER_DUR = 800;186 const u32 AR93X_NSECS_PER_DUR_FAST = (8000 / 11);187 u32 nsecs;188 189 if (IS_CHAN_A_FAST_CLOCK(ah, ah->curchan))190 nsecs = dur * AR93X_NSECS_PER_DUR_FAST;191 else192 nsecs = dur * AR93X_NSECS_PER_DUR;193 194 return (nsecs + 500) / 1000;195}196 197#define PRI_CH_RADAR_FOUND 0x01198#define EXT_CH_RADAR_FOUND 0x02199static bool200ath9k_postprocess_radar_event(struct ath_softc *sc,201 struct ath_radar_data *ard,202 struct pulse_event *pe)203{204 u8 rssi;205 u16 dur;206 207 /*208 * Only the last 2 bits of the BW info are relevant, they indicate209 * which channel the radar was detected in.210 */211 ard->pulse_bw_info &= 0x03;212 213 switch (ard->pulse_bw_info) {214 case PRI_CH_RADAR_FOUND:215 /* radar in ctrl channel */216 dur = ard->pulse_length_pri;217 DFS_STAT_INC(sc, pri_phy_errors);218 /*219 * cannot use ctrl channel RSSI220 * if extension channel is stronger221 */222 rssi = (ard->ext_rssi >= (ard->rssi + 3)) ? 0 : ard->rssi;223 break;224 case EXT_CH_RADAR_FOUND:225 /* radar in extension channel */226 dur = ard->pulse_length_ext;227 DFS_STAT_INC(sc, ext_phy_errors);228 /*229 * cannot use extension channel RSSI230 * if control channel is stronger231 */232 rssi = (ard->rssi >= (ard->ext_rssi + 12)) ? 0 : ard->ext_rssi;233 break;234 case (PRI_CH_RADAR_FOUND | EXT_CH_RADAR_FOUND):235 /*236 * Conducted testing, when pulse is on DC, both pri and ext237 * durations are reported to be same238 *239 * Radiated testing, when pulse is on DC, different pri and240 * ext durations are reported, so take the larger of the two241 */242 if (ard->pulse_length_ext >= ard->pulse_length_pri)243 dur = ard->pulse_length_ext;244 else245 dur = ard->pulse_length_pri;246 DFS_STAT_INC(sc, dc_phy_errors);247 248 /* when both are present use stronger one */249 rssi = max(ard->rssi, ard->ext_rssi);250 break;251 default:252 /*253 * Bogus bandwidth info was received in descriptor,254 * so ignore this PHY error255 */256 DFS_STAT_INC(sc, bwinfo_discards);257 return false;258 }259 260 if (rssi == 0) {261 DFS_STAT_INC(sc, rssi_discards);262 return false;263 }264 265 /* convert duration to usecs */266 pe->width = dur_to_usecs(sc->sc_ah, dur);267 pe->rssi = rssi;268 269 DFS_STAT_INC(sc, pulses_detected);270 return true;271}272 273static void274ath9k_dfs_process_radar_pulse(struct ath_softc *sc, struct pulse_event *pe)275{276 struct dfs_pattern_detector *pd = sc->dfs_detector;277 DFS_STAT_INC(sc, pulses_processed);278 if (pd == NULL)279 return;280 if (!pd->add_pulse(pd, pe, NULL))281 return;282 DFS_STAT_INC(sc, radar_detected);283 ieee80211_radar_detected(sc->hw, NULL);284}285 286/*287 * DFS: check PHY-error for radar pulse and feed the detector288 */289void ath9k_dfs_process_phyerr(struct ath_softc *sc, void *data,290 struct ath_rx_status *rs, u64 mactime)291{292 struct ath_radar_data ard;293 u16 datalen;294 char *vdata_end;295 struct pulse_event pe;296 struct ath_hw *ah = sc->sc_ah;297 struct ath_common *common = ath9k_hw_common(ah);298 299 DFS_STAT_INC(sc, pulses_total);300 if ((rs->rs_phyerr != ATH9K_PHYERR_RADAR) &&301 (rs->rs_phyerr != ATH9K_PHYERR_FALSE_RADAR_EXT)) {302 ath_dbg(common, DFS,303 "Error: rs_phyer=0x%x not a radar error\n",304 rs->rs_phyerr);305 DFS_STAT_INC(sc, pulses_no_dfs);306 return;307 }308 309 datalen = rs->rs_datalen;310 if (datalen == 0) {311 DFS_STAT_INC(sc, datalen_discards);312 return;313 }314 315 ard.rssi = rs->rs_rssi_ctl[0];316 ard.ext_rssi = rs->rs_rssi_ext[0];317 318 /*319 * hardware stores this as 8 bit signed value.320 * we will cap it at 0 if it is a negative number321 */322 if (ard.rssi & 0x80)323 ard.rssi = 0;324 if (ard.ext_rssi & 0x80)325 ard.ext_rssi = 0;326 327 vdata_end = data + datalen;328 ard.pulse_bw_info = vdata_end[-1];329 ard.pulse_length_ext = vdata_end[-2];330 ard.pulse_length_pri = vdata_end[-3];331 pe.freq = ah->curchan->channel;332 pe.ts = mactime;333 if (!ath9k_postprocess_radar_event(sc, &ard, &pe))334 return;335 336 if (pe.width > MIN_CHIRP_PULSE_WIDTH &&337 pe.width < MAX_CHIRP_PULSE_WIDTH) {338 bool is_ctl = !!(ard.pulse_bw_info & PRI_CH_RADAR_FOUND);339 bool is_ext = !!(ard.pulse_bw_info & EXT_CH_RADAR_FOUND);340 int clen = datalen - 3;341 pe.chirp = ath9k_check_chirping(sc, data, clen, is_ctl, is_ext);342 } else {343 pe.chirp = false;344 }345 346 ath_dbg(common, DFS,347 "ath9k_dfs_process_phyerr: type=%d, freq=%d, ts=%llu, "348 "width=%d, rssi=%d, delta_ts=%llu\n",349 ard.pulse_bw_info, pe.freq, pe.ts, pe.width, pe.rssi,350 pe.ts - sc->dfs_prev_pulse_ts);351 sc->dfs_prev_pulse_ts = pe.ts;352 if (ard.pulse_bw_info & PRI_CH_RADAR_FOUND)353 ath9k_dfs_process_radar_pulse(sc, &pe);354 if (IS_CHAN_HT40(ah->curchan) &&355 ard.pulse_bw_info & EXT_CH_RADAR_FOUND) {356 pe.freq += IS_CHAN_HT40PLUS(ah->curchan) ? 20 : -20;357 ath9k_dfs_process_radar_pulse(sc, &pe);358 }359}360#undef PRI_CH_RADAR_FOUND361#undef EXT_CH_RADAR_FOUND362