2 * Copyright (c) 2008-2011 Atheros Communications Inc.
3 * Copyright (c) 2011 Neratec Solutions AG
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.
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.
22 #include "dfs_debug.h"
24 /* internal struct to pass radar data */
25 struct ath_radar_data {
33 /**** begin: CHIRP ************************************************************/
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
39 static const int BIN_DELTA_MIN = 1;
40 static const int BIN_DELTA_MAX = 10;
42 /* we need at least 3 deltas / 4 samples for a reliable chirp detection */
44 static const int FFT_NUM_SAMPLES = (NUM_DIFFS + 1);
46 /* Threshold for difference of delta peaks */
47 static const int MAX_DIFF = 2;
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;
53 struct ath9k_dfs_fft_20 {
57 struct ath9k_dfs_fft_40 {
63 static inline int fft_max_index(u8 *bins)
65 return (bins[2] & 0xfc) >> 2;
67 static inline int fft_max_magnitude(u8 *bins)
69 return (bins[0] & 0xc0) >> 6 | bins[1] << 2 | (bins[2] & 0x03) << 10;
71 static inline u8 fft_bitmap_weight(u8 *bins)
73 return bins[0] & 0x3f;
76 static int ath9k_get_max_index_ht40(struct ath9k_dfs_fft_40 *fft,
77 bool is_ctl, bool is_ext)
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;
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)
97 return fft_max_index(fft->lower_bins);
98 return fft_max_index(fft->upper_bins) + DFS_UPPER_BIN_OFFSET;
100 static bool ath9k_check_chirping(struct ath_softc *sc, u8 *data,
101 int datalen, bool is_ctl, bool is_ext)
104 int max_bin[FFT_NUM_SAMPLES];
105 struct ath_hw *ah = sc->sc_ah;
106 struct ath_common *common = ath9k_hw_common(ah);
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)
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");
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");
126 if (IS_CHAN_HT40MINUS(ah->curchan)) {
131 for (i = 0; i < FFT_NUM_SAMPLES; i++)
132 max_bin[i] = ath9k_get_max_index_ht40(fft + i, is_ctl,
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)
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");
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;
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]);
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
157 for (i = 0; i < NUM_DIFFS; i++) {
159 int delta = max_bin[i + 1] - max_bin[i];
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);
169 ddelta = delta - prev_delta;
170 if (abs(ddelta) > MAX_DIFF) {
171 ath_dbg(common, DFS, "CHIRP: ddelta %d too high\n",
176 ath_dbg(common, DFS, "CHIRP - %d: delta=%d, ddelta=%d\n",
182 /**** end: CHIRP **************************************************************/
184 /* convert pulse duration to usecs, considering clock mode */
185 static u32 dur_to_usecs(struct ath_hw *ah, u32 dur)
187 const u32 AR93X_NSECS_PER_DUR = 800;
188 const u32 AR93X_NSECS_PER_DUR_FAST = (8000 / 11);
191 if (IS_CHAN_A_FAST_CLOCK(ah, ah->curchan))
192 nsecs = dur * AR93X_NSECS_PER_DUR_FAST;
194 nsecs = dur * AR93X_NSECS_PER_DUR;
196 return (nsecs + 500) / 1000;
199 #define PRI_CH_RADAR_FOUND 0x01
200 #define EXT_CH_RADAR_FOUND 0x02
202 ath9k_postprocess_radar_event(struct ath_softc *sc,
203 struct ath_radar_data *ard,
204 struct pulse_event *pe)
210 * Only the last 2 bits of the BW info are relevant, they indicate
211 * which channel the radar was detected in.
213 ard->pulse_bw_info &= 0x03;
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);
221 * cannot use ctrl channel RSSI
222 * if extension channel is stronger
224 rssi = (ard->ext_rssi >= (ard->rssi + 3)) ? 0 : ard->rssi;
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);
231 * cannot use extension channel RSSI
232 * if control channel is stronger
234 rssi = (ard->rssi >= (ard->ext_rssi + 12)) ? 0 : ard->ext_rssi;
236 case (PRI_CH_RADAR_FOUND | EXT_CH_RADAR_FOUND):
238 * Conducted testing, when pulse is on DC, both pri and ext
239 * durations are reported to be same
241 * Radiated testing, when pulse is on DC, different pri and
242 * ext durations are reported, so take the larger of the two
244 if (ard->pulse_length_ext >= ard->pulse_length_pri)
245 dur = ard->pulse_length_ext;
247 dur = ard->pulse_length_pri;
248 DFS_STAT_INC(sc, dc_phy_errors);
250 /* when both are present use stronger one */
251 rssi = (ard->rssi < ard->ext_rssi) ? ard->ext_rssi : ard->rssi;
255 * Bogus bandwidth info was received in descriptor,
256 * so ignore this PHY error
258 DFS_STAT_INC(sc, bwinfo_discards);
263 DFS_STAT_INC(sc, rssi_discards);
267 /* convert duration to usecs */
268 pe->width = dur_to_usecs(sc->sc_ah, dur);
271 DFS_STAT_INC(sc, pulses_detected);
276 ath9k_dfs_process_radar_pulse(struct ath_softc *sc, struct pulse_event *pe)
278 struct dfs_pattern_detector *pd = sc->dfs_detector;
279 DFS_STAT_INC(sc, pulses_processed);
282 if (!pd->add_pulse(pd, pe))
284 DFS_STAT_INC(sc, radar_detected);
285 ieee80211_radar_detected(sc->hw);
289 * DFS: check PHY-error for radar pulse and feed the detector
291 void ath9k_dfs_process_phyerr(struct ath_softc *sc, void *data,
292 struct ath_rx_status *rs, u64 mactime)
294 struct ath_radar_data ard;
297 struct pulse_event pe;
298 struct ath_hw *ah = sc->sc_ah;
299 struct ath_common *common = ath9k_hw_common(ah);
301 DFS_STAT_INC(sc, pulses_total);
302 if ((rs->rs_phyerr != ATH9K_PHYERR_RADAR) &&
303 (rs->rs_phyerr != ATH9K_PHYERR_FALSE_RADAR_EXT)) {
305 "Error: rs_phyer=0x%x not a radar error\n",
307 DFS_STAT_INC(sc, pulses_no_dfs);
311 datalen = rs->rs_datalen;
313 DFS_STAT_INC(sc, datalen_discards);
317 ard.rssi = rs->rs_rssi_ctl[0];
318 ard.ext_rssi = rs->rs_rssi_ext[0];
321 * hardware stores this as 8 bit signed value.
322 * we will cap it at 0 if it is a negative number
326 if (ard.ext_rssi & 0x80)
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;
335 if (!ath9k_postprocess_radar_event(sc, &ard, &pe))
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);
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);
362 #undef PRI_CH_RADAR_FOUND
363 #undef EXT_CH_RADAR_FOUND