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 */ 25 struct 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 by 36 * - 20MHz chirp width over a pulse width of 50us 37 * - 5MHz chirp width over a pulse width of 100us 38 */ 39 static const int BIN_DELTA_MIN = 1; 40 static 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 3 44 static const int FFT_NUM_SAMPLES = (NUM_DIFFS + 1); 45 46 /* Threshold for difference of delta peaks */ 47 static const int MAX_DIFF = 2; 48 49 /* width range to be checked for chirping */ 50 static const int MIN_CHIRP_PULSE_WIDTH = 20; 51 static const int MAX_CHIRP_PULSE_WIDTH = 110; 52 53 struct ath9k_dfs_fft_20 { 54 u8 bin[28]; 55 u8 lower_bins[3]; 56 } __packed; 57 struct ath9k_dfs_fft_40 { 58 u8 bin[64]; 59 u8 lower_bins[3]; 60 u8 upper_bins[3]; 61 } __packed; 62 63 static inline int fft_max_index(u8 *bins) 64 { 65 return (bins[2] & 0xfc) >> 2; 66 } 67 static inline int fft_max_magnitude(u8 *bins) 68 { 69 return (bins[0] & 0xc0) >> 6 | bins[1] << 2 | (bins[2] & 0x03) << 10; 70 } 71 static inline u8 fft_bitmap_weight(u8 *bins) 72 { 73 return bins[0] & 0x3f; 74 } 75 76 static 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 else 93 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 } 100 static 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 int temp = is_ctl; 128 is_ctl = is_ext; 129 is_ext = temp; 130 } 131 for (i = 0; i < FFT_NUM_SAMPLES; i++) 132 max_bin[i] = ath9k_get_max_index_ht40(fft + i, is_ctl, 133 is_ext); 134 } else { 135 struct ath9k_dfs_fft_20 *fft = (struct ath9k_dfs_fft_20 *) data; 136 int num_fft_packets = datalen / sizeof(*fft); 137 if (num_fft_packets == 0) 138 return false; 139 ath_dbg(common, DFS, "HT20: datalen=%d, num_fft_packets=%d\n", 140 datalen, num_fft_packets); 141 if (num_fft_packets < (FFT_NUM_SAMPLES)) { 142 ath_dbg(common, DFS, "not enough packets for chirp\n"); 143 return false; 144 } 145 /* in ht20, this is a 6-bit signed number => shift it to 0 */ 146 for (i = 0; i < FFT_NUM_SAMPLES; i++) 147 max_bin[i] = fft_max_index(fft[i].lower_bins) ^ 0x20; 148 } 149 ath_dbg(common, DFS, "bin_max = [%d, %d, %d, %d]\n", 150 max_bin[0], max_bin[1], max_bin[2], max_bin[3]); 151 152 /* Check for chirp attributes within specs 153 * a) delta of adjacent max_bins is within range 154 * b) delta of adjacent deltas are within tolerance 155 */ 156 prev_delta = 0; 157 for (i = 0; i < NUM_DIFFS; i++) { 158 int ddelta = -1; 159 int delta = max_bin[i + 1] - max_bin[i]; 160 161 /* ensure gradient is within valid range */ 162 if (abs(delta) < BIN_DELTA_MIN || abs(delta) > BIN_DELTA_MAX) { 163 ath_dbg(common, DFS, "CHIRP: invalid delta %d " 164 "in sample %d\n", delta, i); 165 return false; 166 } 167 if (i == 0) 168 goto done; 169 ddelta = delta - prev_delta; 170 if (abs(ddelta) > MAX_DIFF) { 171 ath_dbg(common, DFS, "CHIRP: ddelta %d too high\n", 172 ddelta); 173 return false; 174 } 175 done: 176 ath_dbg(common, DFS, "CHIRP - %d: delta=%d, ddelta=%d\n", 177 i, delta, ddelta); 178 prev_delta = delta; 179 } 180 return true; 181 } 182 /**** end: CHIRP **************************************************************/ 183 184 /* convert pulse duration to usecs, considering clock mode */ 185 static u32 dur_to_usecs(struct ath_hw *ah, u32 dur) 186 { 187 const u32 AR93X_NSECS_PER_DUR = 800; 188 const u32 AR93X_NSECS_PER_DUR_FAST = (8000 / 11); 189 u32 nsecs; 190 191 if (IS_CHAN_A_FAST_CLOCK(ah, ah->curchan)) 192 nsecs = dur * AR93X_NSECS_PER_DUR_FAST; 193 else 194 nsecs = dur * AR93X_NSECS_PER_DUR; 195 196 return (nsecs + 500) / 1000; 197 } 198 199 #define PRI_CH_RADAR_FOUND 0x01 200 #define EXT_CH_RADAR_FOUND 0x02 201 static bool 202 ath9k_postprocess_radar_event(struct ath_softc *sc, 203 struct ath_radar_data *ard, 204 struct pulse_event *pe) 205 { 206 u8 rssi; 207 u16 dur; 208 209 /* 210 * Only the last 2 bits of the BW info are relevant, they indicate 211 * which channel the radar was detected in. 212 */ 213 ard->pulse_bw_info &= 0x03; 214 215 switch (ard->pulse_bw_info) { 216 case PRI_CH_RADAR_FOUND: 217 /* radar in ctrl channel */ 218 dur = ard->pulse_length_pri; 219 DFS_STAT_INC(sc, pri_phy_errors); 220 /* 221 * cannot use ctrl channel RSSI 222 * if extension channel is stronger 223 */ 224 rssi = (ard->ext_rssi >= (ard->rssi + 3)) ? 0 : ard->rssi; 225 break; 226 case EXT_CH_RADAR_FOUND: 227 /* radar in extension channel */ 228 dur = ard->pulse_length_ext; 229 DFS_STAT_INC(sc, ext_phy_errors); 230 /* 231 * cannot use extension channel RSSI 232 * if control channel is stronger 233 */ 234 rssi = (ard->rssi >= (ard->ext_rssi + 12)) ? 0 : ard->ext_rssi; 235 break; 236 case (PRI_CH_RADAR_FOUND | EXT_CH_RADAR_FOUND): 237 /* 238 * Conducted testing, when pulse is on DC, both pri and ext 239 * durations are reported to be same 240 * 241 * Radiated testing, when pulse is on DC, different pri and 242 * ext durations are reported, so take the larger of the two 243 */ 244 if (ard->pulse_length_ext >= ard->pulse_length_pri) 245 dur = ard->pulse_length_ext; 246 else 247 dur = ard->pulse_length_pri; 248 DFS_STAT_INC(sc, dc_phy_errors); 249 250 /* when both are present use stronger one */ 251 rssi = (ard->rssi < ard->ext_rssi) ? ard->ext_rssi : ard->rssi; 252 break; 253 default: 254 /* 255 * Bogus bandwidth info was received in descriptor, 256 * so ignore this PHY error 257 */ 258 DFS_STAT_INC(sc, bwinfo_discards); 259 return false; 260 } 261 262 if (rssi == 0) { 263 DFS_STAT_INC(sc, rssi_discards); 264 return false; 265 } 266 267 /* convert duration to usecs */ 268 pe->width = dur_to_usecs(sc->sc_ah, dur); 269 pe->rssi = rssi; 270 271 DFS_STAT_INC(sc, pulses_detected); 272 return true; 273 } 274 275 static void 276 ath9k_dfs_process_radar_pulse(struct ath_softc *sc, struct pulse_event *pe) 277 { 278 struct dfs_pattern_detector *pd = sc->dfs_detector; 279 DFS_STAT_INC(sc, pulses_processed); 280 if (pd == NULL) 281 return; 282 if (!pd->add_pulse(pd, pe)) 283 return; 284 DFS_STAT_INC(sc, radar_detected); 285 ieee80211_radar_detected(sc->hw); 286 } 287 288 /* 289 * DFS: check PHY-error for radar pulse and feed the detector 290 */ 291 void ath9k_dfs_process_phyerr(struct ath_softc *sc, void *data, 292 struct ath_rx_status *rs, u64 mactime) 293 { 294 struct ath_radar_data ard; 295 u16 datalen; 296 char *vdata_end; 297 struct pulse_event pe; 298 struct ath_hw *ah = sc->sc_ah; 299 struct ath_common *common = ath9k_hw_common(ah); 300 301 DFS_STAT_INC(sc, pulses_total); 302 if ((rs->rs_phyerr != ATH9K_PHYERR_RADAR) && 303 (rs->rs_phyerr != ATH9K_PHYERR_FALSE_RADAR_EXT)) { 304 ath_dbg(common, DFS, 305 "Error: rs_phyer=0x%x not a radar error\n", 306 rs->rs_phyerr); 307 DFS_STAT_INC(sc, pulses_no_dfs); 308 return; 309 } 310 311 datalen = rs->rs_datalen; 312 if (datalen == 0) { 313 DFS_STAT_INC(sc, datalen_discards); 314 return; 315 } 316 317 ard.rssi = rs->rs_rssi_ctl[0]; 318 ard.ext_rssi = rs->rs_rssi_ext[0]; 319 320 /* 321 * hardware stores this as 8 bit signed value. 322 * we will cap it at 0 if it is a negative number 323 */ 324 if (ard.rssi & 0x80) 325 ard.rssi = 0; 326 if (ard.ext_rssi & 0x80) 327 ard.ext_rssi = 0; 328 329 vdata_end = (char *)data + datalen; 330 ard.pulse_bw_info = vdata_end[-1]; 331 ard.pulse_length_ext = vdata_end[-2]; 332 ard.pulse_length_pri = vdata_end[-3]; 333 pe.freq = ah->curchan->channel; 334 pe.ts = mactime; 335 if (!ath9k_postprocess_radar_event(sc, &ard, &pe)) 336 return; 337 338 if (pe.width > MIN_CHIRP_PULSE_WIDTH && 339 pe.width < MAX_CHIRP_PULSE_WIDTH) { 340 bool is_ctl = !!(ard.pulse_bw_info & PRI_CH_RADAR_FOUND); 341 bool is_ext = !!(ard.pulse_bw_info & EXT_CH_RADAR_FOUND); 342 int clen = datalen - 3; 343 pe.chirp = ath9k_check_chirping(sc, data, clen, is_ctl, is_ext); 344 } else { 345 pe.chirp = false; 346 } 347 348 ath_dbg(common, DFS, 349 "ath9k_dfs_process_phyerr: type=%d, freq=%d, ts=%llu, " 350 "width=%d, rssi=%d, delta_ts=%llu\n", 351 ard.pulse_bw_info, pe.freq, pe.ts, pe.width, pe.rssi, 352 pe.ts - sc->dfs_prev_pulse_ts); 353 sc->dfs_prev_pulse_ts = pe.ts; 354 if (ard.pulse_bw_info & PRI_CH_RADAR_FOUND) 355 ath9k_dfs_process_radar_pulse(sc, &pe); 356 if (IS_CHAN_HT40(ah->curchan) && 357 ard.pulse_bw_info & EXT_CH_RADAR_FOUND) { 358 pe.freq += IS_CHAN_HT40PLUS(ah->curchan) ? 20 : -20; 359 ath9k_dfs_process_radar_pulse(sc, &pe); 360 } 361 } 362 #undef PRI_CH_RADAR_FOUND 363 #undef EXT_CH_RADAR_FOUND 364