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/* convert pulse duration to usecs, considering clock mode */
 34static u32 dur_to_usecs(struct ath_hw *ah, u32 dur)
 35{
 36	const u32 AR93X_NSECS_PER_DUR = 800;
 37	const u32 AR93X_NSECS_PER_DUR_FAST = (8000 / 11);
 38	u32 nsecs;
 39
 40	if (IS_CHAN_A_FAST_CLOCK(ah, ah->curchan))
 41		nsecs = dur * AR93X_NSECS_PER_DUR_FAST;
 42	else
 43		nsecs = dur * AR93X_NSECS_PER_DUR;
 44
 45	return (nsecs + 500) / 1000;
 46}
 47
 48#define PRI_CH_RADAR_FOUND 0x01
 49#define EXT_CH_RADAR_FOUND 0x02
 50static bool
 51ath9k_postprocess_radar_event(struct ath_softc *sc,
 52			      struct ath_radar_data *ard,
 53			      struct pulse_event *pe)
 54{
 55	u8 rssi;
 56	u16 dur;
 57
 58	ath_dbg(ath9k_hw_common(sc->sc_ah), DFS,
 59		"pulse_bw_info=0x%x, pri,ext len/rssi=(%u/%u, %u/%u)\n",
 60		ard->pulse_bw_info,
 61		ard->pulse_length_pri, ard->rssi,
 62		ard->pulse_length_ext, ard->ext_rssi);
 63
 64	/*
 65	 * Only the last 2 bits of the BW info are relevant, they indicate
 66	 * which channel the radar was detected in.
 67	 */
 68	ard->pulse_bw_info &= 0x03;
 69
 70	switch (ard->pulse_bw_info) {
 71	case PRI_CH_RADAR_FOUND:
 72		/* radar in ctrl channel */
 73		dur = ard->pulse_length_pri;
 74		DFS_STAT_INC(sc, pri_phy_errors);
 75		/*
 76		 * cannot use ctrl channel RSSI
 77		 * if extension channel is stronger
 78		 */
 79		rssi = (ard->ext_rssi >= (ard->rssi + 3)) ? 0 : ard->rssi;
 80		break;
 81	case EXT_CH_RADAR_FOUND:
 82		/* radar in extension channel */
 83		dur = ard->pulse_length_ext;
 84		DFS_STAT_INC(sc, ext_phy_errors);
 85		/*
 86		 * cannot use extension channel RSSI
 87		 * if control channel is stronger
 88		 */
 89		rssi = (ard->rssi >= (ard->ext_rssi + 12)) ? 0 : ard->ext_rssi;
 90		break;
 91	case (PRI_CH_RADAR_FOUND | EXT_CH_RADAR_FOUND):
 92		/*
 93		 * Conducted testing, when pulse is on DC, both pri and ext
 94		 * durations are reported to be same
 95		 *
 96		 * Radiated testing, when pulse is on DC, different pri and
 97		 * ext durations are reported, so take the larger of the two
 98		 */
 99		if (ard->pulse_length_ext >= ard->pulse_length_pri)
100			dur = ard->pulse_length_ext;
101		else
102			dur = ard->pulse_length_pri;
103		DFS_STAT_INC(sc, dc_phy_errors);
104
105		/* when both are present use stronger one */
106		rssi = (ard->rssi < ard->ext_rssi) ? ard->ext_rssi : ard->rssi;
107		break;
108	default:
109		/*
110		 * Bogus bandwidth info was received in descriptor,
111		 * so ignore this PHY error
112		 */
113		DFS_STAT_INC(sc, bwinfo_discards);
114		return false;
115	}
116
117	if (rssi == 0) {
118		DFS_STAT_INC(sc, rssi_discards);
119		return false;
120	}
121
122	/*
123	 * TODO: check chirping pulses
124	 *	 checks for chirping are dependent on the DFS regulatory domain
125	 *	 used, which is yet TBD
126	 */
127
128	/* convert duration to usecs */
129	pe->width = dur_to_usecs(sc->sc_ah, dur);
130	pe->rssi = rssi;
131
132	DFS_STAT_INC(sc, pulses_detected);
133	return true;
134}
135#undef PRI_CH_RADAR_FOUND
136#undef EXT_CH_RADAR_FOUND
137
138/*
139 * DFS: check PHY-error for radar pulse and feed the detector
140 */
141void ath9k_dfs_process_phyerr(struct ath_softc *sc, void *data,
142			      struct ath_rx_status *rs, u64 mactime)
143{
144	struct ath_radar_data ard;
145	u16 datalen;
146	char *vdata_end;
147	struct pulse_event pe;
148	struct ath_hw *ah = sc->sc_ah;
149	struct ath_common *common = ath9k_hw_common(ah);
150
151	DFS_STAT_INC(sc, pulses_total);
152	if ((rs->rs_phyerr != ATH9K_PHYERR_RADAR) &&
153	    (rs->rs_phyerr != ATH9K_PHYERR_FALSE_RADAR_EXT)) {
154		ath_dbg(common, DFS,
155			"Error: rs_phyer=0x%x not a radar error\n",
156			rs->rs_phyerr);
157		DFS_STAT_INC(sc, pulses_no_dfs);
158		return;
159	}
160
161	datalen = rs->rs_datalen;
162	if (datalen == 0) {
163		DFS_STAT_INC(sc, datalen_discards);
164		return;
165	}
166
167	ard.rssi = rs->rs_rssi_ctl0;
168	ard.ext_rssi = rs->rs_rssi_ext0;
169
170	/*
171	 * hardware stores this as 8 bit signed value.
172	 * we will cap it at 0 if it is a negative number
173	 */
174	if (ard.rssi & 0x80)
175		ard.rssi = 0;
176	if (ard.ext_rssi & 0x80)
177		ard.ext_rssi = 0;
178
179	vdata_end = (char *)data + datalen;
180	ard.pulse_bw_info = vdata_end[-1];
181	ard.pulse_length_ext = vdata_end[-2];
182	ard.pulse_length_pri = vdata_end[-3];
183	pe.freq = ah->curchan->channel;
184	pe.ts = mactime;
185	if (ath9k_postprocess_radar_event(sc, &ard, &pe)) {
186		struct dfs_pattern_detector *pd = sc->dfs_detector;
187		static u64 last_ts;
188		ath_dbg(common, DFS,
189			"ath9k_dfs_process_phyerr: channel=%d, ts=%llu, "
190			"width=%d, rssi=%d, delta_ts=%llu\n",
191			pe.freq, pe.ts, pe.width, pe.rssi, pe.ts-last_ts);
192		last_ts = pe.ts;
193		DFS_STAT_INC(sc, pulses_processed);
194		if (pd != NULL && pd->add_pulse(pd, &pe)) {
195			DFS_STAT_INC(sc, radar_detected);
196			/*
197			 * TODO: forward radar event to DFS management layer
198			 */
199		}
200	}
201}