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 ; |
28 | u8 ; |
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 | #define 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(bins: fft->lower_bins) != 0; |
84 | is_ext = fft_bitmap_weight(bins: 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(bins: fft->lower_bins); |
89 | int mag_upper = fft_max_magnitude(bins: 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(bins: fft->lower_bins); |
98 | return fft_max_index(bins: 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 | 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: 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(bins: 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 | } |
173 | done: |
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 */ |
183 | static 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 |
199 | static bool |
200 | ath9k_postprocess_radar_event(struct ath_softc *sc, |
201 | struct ath_radar_data *ard, |
202 | struct pulse_event *pe) |
203 | { |
204 | u8 ; |
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(ah: sc->sc_ah, dur); |
267 | pe->rssi = rssi; |
268 | |
269 | DFS_STAT_INC(sc, pulses_detected); |
270 | return true; |
271 | } |
272 | |
273 | static void |
274 | ath9k_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(hw: sc->hw); |
284 | } |
285 | |
286 | /* |
287 | * DFS: check PHY-error for radar pulse and feed the detector |
288 | */ |
289 | void 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: &ard, pe: &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, datalen: 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: &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: &pe); |
358 | } |
359 | } |
360 | #undef PRI_CH_RADAR_FOUND |
361 | #undef EXT_CH_RADAR_FOUND |
362 | |