aboutsummaryrefslogtreecommitdiff
path: root/drivers/net/wireless/ath/ath9k/dfs.c
blob: 7187d3671512eae62e3e1da59bb1aea9866a7be8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
/*
 * Copyright (c) 2008-2011 Atheros Communications Inc.
 * Copyright (c) 2011 Neratec Solutions AG
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "hw.h"
#include "hw-ops.h"
#include "ath9k.h"
#include "dfs.h"
#include "dfs_debug.h"

/* internal struct to pass radar data */
struct ath_radar_data {
	u8 pulse_bw_info;
	u8 rssi;
	u8 ext_rssi;
	u8 pulse_length_ext;
	u8 pulse_length_pri;
};

/* convert pulse duration to usecs, considering clock mode */
static u32 dur_to_usecs(struct ath_hw *ah, u32 dur)
{
	const u32 AR93X_NSECS_PER_DUR = 800;
	const u32 AR93X_NSECS_PER_DUR_FAST = (8000 / 11);
	u32 nsecs;

	if (IS_CHAN_A_FAST_CLOCK(ah, ah->curchan))
		nsecs = dur * AR93X_NSECS_PER_DUR_FAST;
	else
		nsecs = dur * AR93X_NSECS_PER_DUR;

	return (nsecs + 500) / 1000;
}

#define PRI_CH_RADAR_FOUND 0x01
#define EXT_CH_RADAR_FOUND 0x02
static bool
ath9k_postprocess_radar_event(struct ath_softc *sc,
			      struct ath_radar_data *ard,
			      struct pulse_event *pe)
{
	u8 rssi;
	u16 dur;

	/*
	 * Only the last 2 bits of the BW info are relevant, they indicate
	 * which channel the radar was detected in.
	 */
	ard->pulse_bw_info &= 0x03;

	switch (ard->pulse_bw_info) {
	case PRI_CH_RADAR_FOUND:
		/* radar in ctrl channel */
		dur = ard->pulse_length_pri;
		DFS_STAT_INC(sc, pri_phy_errors);
		/*
		 * cannot use ctrl channel RSSI
		 * if extension channel is stronger
		 */
		rssi = (ard->ext_rssi >= (ard->rssi + 3)) ? 0 : ard->rssi;
		break;
	case EXT_CH_RADAR_FOUND:
		/* radar in extension channel */
		dur = ard->pulse_length_ext;
		DFS_STAT_INC(sc, ext_phy_errors);
		/*
		 * cannot use extension channel RSSI
		 * if control channel is stronger
		 */
		rssi = (ard->rssi >= (ard->ext_rssi + 12)) ? 0 : ard->ext_rssi;
		break;
	case (PRI_CH_RADAR_FOUND | EXT_CH_RADAR_FOUND):
		/*
		 * Conducted testing, when pulse is on DC, both pri and ext
		 * durations are reported to be same
		 *
		 * Radiated testing, when pulse is on DC, different pri and
		 * ext durations are reported, so take the larger of the two
		 */
		if (ard->pulse_length_ext >= ard->pulse_length_pri)
			dur = ard->pulse_length_ext;
		else
			dur = ard->pulse_length_pri;
		DFS_STAT_INC(sc, dc_phy_errors);

		/* when both are present use stronger one */
		rssi = (ard->rssi < ard->ext_rssi) ? ard->ext_rssi : ard->rssi;
		break;
	default:
		/*
		 * Bogus bandwidth info was received in descriptor,
		 * so ignore this PHY error
		 */
		DFS_STAT_INC(sc, bwinfo_discards);
		return false;
	}

	if (rssi == 0) {
		DFS_STAT_INC(sc, rssi_discards);
		return false;
	}

	/*
	 * TODO: check chirping pulses
	 *	 checks for chirping are dependent on the DFS regulatory domain
	 *	 used, which is yet TBD
	 */

	/* convert duration to usecs */
	pe->width = dur_to_usecs(sc->sc_ah, dur);
	pe->rssi = rssi;

	DFS_STAT_INC(sc, pulses_detected);
	return true;
}
#undef PRI_CH_RADAR_FOUND
#undef EXT_CH_RADAR_FOUND

/*
 * DFS: check PHY-error for radar pulse and feed the detector
 */
void ath9k_dfs_process_phyerr(struct ath_softc *sc, void *data,
			      struct ath_rx_status *rs, u64 mactime)
{
	struct ath_radar_data ard;
	u16 datalen;
	char *vdata_end;
	struct pulse_event pe;
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);

	DFS_STAT_INC(sc, pulses_total);
	if ((rs->rs_phyerr != ATH9K_PHYERR_RADAR) &&
	    (rs->rs_phyerr != ATH9K_PHYERR_FALSE_RADAR_EXT)) {
		ath_dbg(common, DFS,
			"Error: rs_phyer=0x%x not a radar error\n",
			rs->rs_phyerr);
		DFS_STAT_INC(sc, pulses_no_dfs);
		return;
	}

	datalen = rs->rs_datalen;
	if (datalen == 0) {
		DFS_STAT_INC(sc, datalen_discards);
		return;
	}

	ard.rssi = rs->rs_rssi_ctl0;
	ard.ext_rssi = rs->rs_rssi_ext0;

	/*
	 * hardware stores this as 8 bit signed value.
	 * we will cap it at 0 if it is a negative number
	 */
	if (ard.rssi & 0x80)
		ard.rssi = 0;
	if (ard.ext_rssi & 0x80)
		ard.ext_rssi = 0;

	vdata_end = (char *)data + datalen;
	ard.pulse_bw_info = vdata_end[-1];
	ard.pulse_length_ext = vdata_end[-2];
	ard.pulse_length_pri = vdata_end[-3];
	pe.freq = ah->curchan->channel;
	pe.ts = mactime;
	if (ath9k_postprocess_radar_event(sc, &ard, &pe)) {
		struct dfs_pattern_detector *pd = sc->dfs_detector;
		static u64 last_ts;
		ath_dbg(common, DFS,
			"ath9k_dfs_process_phyerr: channel=%d, ts=%llu, "
			"width=%d, rssi=%d, delta_ts=%llu\n",
			pe.freq, pe.ts, pe.width, pe.rssi, pe.ts-last_ts);
		last_ts = pe.ts;
		DFS_STAT_INC(sc, pulses_processed);
		if (pd != NULL && pd->add_pulse(pd, &pe)) {
			DFS_STAT_INC(sc, radar_detected);
			ieee80211_radar_detected(sc->hw);
		}
	}
}