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/**** 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 */ 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 3 44#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 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} 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 specs 151 * a) delta of adjacent max_bins is within range 152 * b) delta of adjacent deltas are within tolerance 153 */ 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 else 192 nsecs = dur * AR93X_NSECS_PER_DUR; 193 194 return (nsecs + 500) / 1000; 195} 196 197#define PRI_CH_RADAR_FOUND 0x01 198#define EXT_CH_RADAR_FOUND 0x02 199static bool 200ath9k_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 indicate 209 * 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 RSSI 220 * if extension channel is stronger 221 */ 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 RSSI 230 * if control channel is stronger 231 */ 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 ext 237 * durations are reported to be same 238 * 239 * Radiated testing, when pulse is on DC, different pri and 240 * ext durations are reported, so take the larger of the two 241 */ 242 if (ard->pulse_length_ext >= ard->pulse_length_pri) 243 dur = ard->pulse_length_ext; 244 else 245 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 error 255 */ 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 void 274ath9k_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); 284} 285 286/* 287 * DFS: check PHY-error for radar pulse and feed the detector 288 */ 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 number 321 */ 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_FOUND 361#undef EXT_CH_RADAR_FOUND 362