drivers/net/wireless/ath/ath9k/dfs.c - linux - Git at Google

 /*
  * 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;
 };

 /**** begin: CHIRP ************************************************************/

 /* min and max gradients for defined FCC chirping pulses, given by
  * - 20MHz chirp width over a pulse width of  50us
  * -  5MHz chirp width over a pulse width of 100us
  */
 static const int BIN_DELTA_MIN		= 1;
 static const int BIN_DELTA_MAX		= 10;

 /* we need at least 3 deltas / 4 samples for a reliable chirp detection */
 #define NUM_DIFFS 3
 #define FFT_NUM_SAMPLES		(NUM_DIFFS + 1)

 /* Threshold for difference of delta peaks */
 static const int MAX_DIFF		= 2;

 /* width range to be checked for chirping */
 static const int MIN_CHIRP_PULSE_WIDTH	= 20;
 static const int MAX_CHIRP_PULSE_WIDTH	= 110;

 struct ath9k_dfs_fft_20 {
 	u8 bin[28];
 	u8 lower_bins[3];
 } __packed;
 struct ath9k_dfs_fft_40 {
 	u8 bin[64];
 	u8 lower_bins[3];
 	u8 upper_bins[3];
 } __packed;

 static inline int fft_max_index(u8 *bins)
 {
 	return (bins[2] & 0xfc) >> 2;
 }
 static inline int fft_max_magnitude(u8 *bins)
 {
 	return (bins[0] & 0xc0) >> 6 | bins[1] << 2 | (bins[2] & 0x03) << 10;
 }
 static inline u8 fft_bitmap_weight(u8 *bins)
 {
 	return bins[0] & 0x3f;
 }

 static int ath9k_get_max_index_ht40(struct ath9k_dfs_fft_40 *fft,
 				    bool is_ctl, bool is_ext)
 {
 	const int DFS_UPPER_BIN_OFFSET = 64;
 	/* if detected radar on both channels, select the significant one */
 	if (is_ctl && is_ext) {
 		/* first check wether channels have 'strong' bins */
 		is_ctl = fft_bitmap_weight(fft->lower_bins) != 0;
 		is_ext = fft_bitmap_weight(fft->upper_bins) != 0;

 		/* if still unclear, take higher magnitude */
 		if (is_ctl && is_ext) {
 			int mag_lower = fft_max_magnitude(fft->lower_bins);
 			int mag_upper = fft_max_magnitude(fft->upper_bins);
 			if (mag_upper > mag_lower)
 				is_ctl = false;
 			else
 				is_ext = false;
 		}
 	}
 	if (is_ctl)
 		return fft_max_index(fft->lower_bins);
 	return fft_max_index(fft->upper_bins) + DFS_UPPER_BIN_OFFSET;
 }
 static bool ath9k_check_chirping(struct ath_softc *sc, u8 *data,
 				 int datalen, bool is_ctl, bool is_ext)
 {
 	int i;
 	int max_bin[FFT_NUM_SAMPLES];
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
 	int prev_delta;

 	if (IS_CHAN_HT40(ah->curchan)) {
 		struct ath9k_dfs_fft_40 *fft = (struct ath9k_dfs_fft_40 *) data;
 		int num_fft_packets = datalen / sizeof(*fft);
 		if (num_fft_packets == 0)
 			return false;

 		ath_dbg(common, DFS, "HT40: datalen=%d, num_fft_packets=%d\n",
 			datalen, num_fft_packets);
 		if (num_fft_packets < FFT_NUM_SAMPLES) {
 			ath_dbg(common, DFS, "not enough packets for chirp\n");
 			return false;
 		}
 		/* HW sometimes adds 2 garbage bytes in front of FFT samples */
 		if ((datalen % sizeof(*fft)) == 2) {
 			fft = (struct ath9k_dfs_fft_40 *) (data + 2);
 			ath_dbg(common, DFS, "fixing datalen by 2\n");
 		}
 		if (IS_CHAN_HT40MINUS(ah->curchan))
 			swap(is_ctl, is_ext);

 		for (i = 0; i < FFT_NUM_SAMPLES; i++)
 			max_bin[i] = ath9k_get_max_index_ht40(fft + i, is_ctl,
 							      is_ext);
 	} else {
 		struct ath9k_dfs_fft_20 *fft = (struct ath9k_dfs_fft_20 *) data;
 		int num_fft_packets = datalen / sizeof(*fft);
 		if (num_fft_packets == 0)
 			return false;
 		ath_dbg(common, DFS, "HT20: datalen=%d, num_fft_packets=%d\n",
 			datalen, num_fft_packets);
 		if (num_fft_packets < FFT_NUM_SAMPLES) {
 			ath_dbg(common, DFS, "not enough packets for chirp\n");
 			return false;
 		}
 		/* in ht20, this is a 6-bit signed number => shift it to 0 */
 		for (i = 0; i < FFT_NUM_SAMPLES; i++)
 			max_bin[i] = fft_max_index(fft[i].lower_bins) ^ 0x20;
 	}
 	ath_dbg(common, DFS, "bin_max = [%d, %d, %d, %d]\n",
 		max_bin[0], max_bin[1], max_bin[2], max_bin[3]);

 	/* Check for chirp attributes within specs
 	 * a) delta of adjacent max_bins is within range
 	 * b) delta of adjacent deltas are within tolerance
 	 */
 	prev_delta = 0;
 	for (i = 0; i < NUM_DIFFS; i++) {
 		int ddelta = -1;
 		int delta = max_bin[i + 1] - max_bin[i];

 		/* ensure gradient is within valid range */
 		if (abs(delta) < BIN_DELTA_MIN || abs(delta) > BIN_DELTA_MAX) {
 			ath_dbg(common, DFS, "CHIRP: invalid delta %d "
 				"in sample %d\n", delta, i);
 			return false;
 		}
 		if (i == 0)
 			goto done;
 		ddelta = delta - prev_delta;
 		if (abs(ddelta) > MAX_DIFF) {
 			ath_dbg(common, DFS, "CHIRP: ddelta %d too high\n",
 				ddelta);
 			return false;
 		}
 done:
 		ath_dbg(common, DFS, "CHIRP - %d: delta=%d, ddelta=%d\n",
 			i, delta, ddelta);
 		prev_delta = delta;
 	}
 	return true;
 }
 /**** end: CHIRP **************************************************************/

 /* 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 = max(ard->rssi, ard->ext_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;
 	}

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

 	DFS_STAT_INC(sc, pulses_detected);
 	return true;
 }

 static void
 ath9k_dfs_process_radar_pulse(struct ath_softc *sc, struct pulse_event *pe)
 {
 	struct dfs_pattern_detector *pd = sc->dfs_detector;
 	DFS_STAT_INC(sc, pulses_processed);
 	if (pd == NULL)
 		return;
 	if (!pd->add_pulse(pd, pe, NULL))
 		return;
 	DFS_STAT_INC(sc, radar_detected);
 	ieee80211_radar_detected(sc->hw, NULL);
 }

 /*
  * 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_ctl[0];
 	ard.ext_rssi = rs->rs_rssi_ext[0];

 	/*
 	 * 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 = 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))
 		return;

 	if (pe.width > MIN_CHIRP_PULSE_WIDTH &&
 	    pe.width < MAX_CHIRP_PULSE_WIDTH) {
 		bool is_ctl = !!(ard.pulse_bw_info & PRI_CH_RADAR_FOUND);
 		bool is_ext = !!(ard.pulse_bw_info & EXT_CH_RADAR_FOUND);
 		int clen = datalen - 3;
 		pe.chirp = ath9k_check_chirping(sc, data, clen, is_ctl, is_ext);
 	} else {
 		pe.chirp = false;
 	}

 	ath_dbg(common, DFS,
 		"ath9k_dfs_process_phyerr: type=%d, freq=%d, ts=%llu, "
 		"width=%d, rssi=%d, delta_ts=%llu\n",
 		ard.pulse_bw_info, pe.freq, pe.ts, pe.width, pe.rssi,
 		pe.ts - sc->dfs_prev_pulse_ts);
 	sc->dfs_prev_pulse_ts = pe.ts;
 	if (ard.pulse_bw_info & PRI_CH_RADAR_FOUND)
 		ath9k_dfs_process_radar_pulse(sc, &pe);
 	if (IS_CHAN_HT40(ah->curchan) &&
 	    ard.pulse_bw_info & EXT_CH_RADAR_FOUND) {
 		pe.freq += IS_CHAN_HT40PLUS(ah->curchan) ? 20 : -20;
 		ath9k_dfs_process_radar_pulse(sc, &pe);
 	}
 }
 #undef PRI_CH_RADAR_FOUND
 #undef EXT_CH_RADAR_FOUND
	/*
	* 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;
	};

	/** begin: CHIRP **********************************************************/

	/* min and max gradients for defined FCC chirping pulses, given by
	* - 20MHz chirp width over a pulse width of 50us
	* - 5MHz chirp width over a pulse width of 100us
	*/
	static const int BIN_DELTA_MIN = 1;
	static const int BIN_DELTA_MAX = 10;

	/* we need at least 3 deltas / 4 samples for a reliable chirp detection */
	#define NUM_DIFFS 3
	#define FFT_NUM_SAMPLES (NUM_DIFFS + 1)

	/* Threshold for difference of delta peaks */
	static const int MAX_DIFF = 2;

	/* width range to be checked for chirping */
	static const int MIN_CHIRP_PULSE_WIDTH = 20;
	static const int MAX_CHIRP_PULSE_WIDTH = 110;

	struct ath9k_dfs_fft_20 {
	u8 bin[28];
	u8 lower_bins[3];
	} __packed;
	struct ath9k_dfs_fft_40 {
	u8 bin[64];
	u8 lower_bins[3];
	u8 upper_bins[3];
	} __packed;

	static inline int fft_max_index(u8 *bins)
	{
	return (bins[2] & 0xfc) >> 2;
	}
	static inline int fft_max_magnitude(u8 *bins)
	{
	return (bins[0] & 0xc0) >> 6 \| bins[1] << 2 \| (bins[2] & 0x03) << 10;
	}
	static inline u8 fft_bitmap_weight(u8 *bins)
	{
	return bins[0] & 0x3f;
	}

	static int ath9k_get_max_index_ht40(struct ath9k_dfs_fft_40 *fft,
	bool is_ctl, bool is_ext)
	{
	const int DFS_UPPER_BIN_OFFSET = 64;
	/* if detected radar on both channels, select the significant one */
	if (is_ctl && is_ext) {
	/* first check wether channels have 'strong' bins */
	is_ctl = fft_bitmap_weight(fft->lower_bins) != 0;
	is_ext = fft_bitmap_weight(fft->upper_bins) != 0;

	/* if still unclear, take higher magnitude */
	if (is_ctl && is_ext) {
	int mag_lower = fft_max_magnitude(fft->lower_bins);
	int mag_upper = fft_max_magnitude(fft->upper_bins);
	if (mag_upper > mag_lower)
	is_ctl = false;
	else
	is_ext = false;
	}
	}
	if (is_ctl)
	return fft_max_index(fft->lower_bins);
	return fft_max_index(fft->upper_bins) + DFS_UPPER_BIN_OFFSET;
	}
	static bool ath9k_check_chirping(struct ath_softc sc, u8 data,
	int datalen, bool is_ctl, bool is_ext)
	{
	int i;
	int max_bin[FFT_NUM_SAMPLES];
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);
	int prev_delta;

	if (IS_CHAN_HT40(ah->curchan)) {
	struct ath9k_dfs_fft_40 fft = (struct ath9k_dfs_fft_40 ) data;
	int num_fft_packets = datalen / sizeof(*fft);
	if (num_fft_packets == 0)
	return false;

	ath_dbg(common, DFS, "HT40: datalen=%d, num_fft_packets=%d\n",
	datalen, num_fft_packets);
	if (num_fft_packets < FFT_NUM_SAMPLES) {
	ath_dbg(common, DFS, "not enough packets for chirp\n");
	return false;
	}
	/* HW sometimes adds 2 garbage bytes in front of FFT samples */
	if ((datalen % sizeof(*fft)) == 2) {
	fft = (struct ath9k_dfs_fft_40 *) (data + 2);
	ath_dbg(common, DFS, "fixing datalen by 2\n");
	}
	if (IS_CHAN_HT40MINUS(ah->curchan))
	swap(is_ctl, is_ext);

	for (i = 0; i < FFT_NUM_SAMPLES; i++)
	max_bin[i] = ath9k_get_max_index_ht40(fft + i, is_ctl,
	is_ext);
	} else {
	struct ath9k_dfs_fft_20 fft = (struct ath9k_dfs_fft_20 ) data;
	int num_fft_packets = datalen / sizeof(*fft);
	if (num_fft_packets == 0)
	return false;
	ath_dbg(common, DFS, "HT20: datalen=%d, num_fft_packets=%d\n",
	datalen, num_fft_packets);
	if (num_fft_packets < FFT_NUM_SAMPLES) {
	ath_dbg(common, DFS, "not enough packets for chirp\n");
	return false;
	}
	/* in ht20, this is a 6-bit signed number => shift it to 0 */
	for (i = 0; i < FFT_NUM_SAMPLES; i++)
	max_bin[i] = fft_max_index(fft[i].lower_bins) ^ 0x20;
	}
	ath_dbg(common, DFS, "bin_max = [%d, %d, %d, %d]\n",
	max_bin[0], max_bin[1], max_bin[2], max_bin[3]);

	/* Check for chirp attributes within specs
	* a) delta of adjacent max_bins is within range
	* b) delta of adjacent deltas are within tolerance
	*/
	prev_delta = 0;
	for (i = 0; i < NUM_DIFFS; i++) {
	int ddelta = -1;
	int delta = max_bin[i + 1] - max_bin[i];

	/* ensure gradient is within valid range */
	if (abs(delta) < BIN_DELTA_MIN \|\| abs(delta) > BIN_DELTA_MAX) {
	ath_dbg(common, DFS, "CHIRP: invalid delta %d "
	"in sample %d\n", delta, i);
	return false;
	}
	if (i == 0)
	goto done;
	ddelta = delta - prev_delta;
	if (abs(ddelta) > MAX_DIFF) {
	ath_dbg(common, DFS, "CHIRP: ddelta %d too high\n",
	ddelta);
	return false;
	}
	done:
	ath_dbg(common, DFS, "CHIRP - %d: delta=%d, ddelta=%d\n",
	i, delta, ddelta);
	prev_delta = delta;
	}
	return true;
	}
	/** end: CHIRP ************************************************************/

	/* 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 = max(ard->rssi, ard->ext_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;
	}

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

	DFS_STAT_INC(sc, pulses_detected);
	return true;
	}

	static void
	ath9k_dfs_process_radar_pulse(struct ath_softc sc, struct pulse_event pe)
	{
	struct dfs_pattern_detector *pd = sc->dfs_detector;
	DFS_STAT_INC(sc, pulses_processed);
	if (pd == NULL)
	return;
	if (!pd->add_pulse(pd, pe, NULL))
	return;
	DFS_STAT_INC(sc, radar_detected);
	ieee80211_radar_detected(sc->hw, NULL);
	}

	/*
	* 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_ctl[0];
	ard.ext_rssi = rs->rs_rssi_ext[0];

	/*
	* 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 = 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))
	return;

	if (pe.width > MIN_CHIRP_PULSE_WIDTH &&
	pe.width < MAX_CHIRP_PULSE_WIDTH) {
	bool is_ctl = !!(ard.pulse_bw_info & PRI_CH_RADAR_FOUND);
	bool is_ext = !!(ard.pulse_bw_info & EXT_CH_RADAR_FOUND);
	int clen = datalen - 3;
	pe.chirp = ath9k_check_chirping(sc, data, clen, is_ctl, is_ext);
	} else {
	pe.chirp = false;
	}

	ath_dbg(common, DFS,
	"ath9k_dfs_process_phyerr: type=%d, freq=%d, ts=%llu, "
	"width=%d, rssi=%d, delta_ts=%llu\n",
	ard.pulse_bw_info, pe.freq, pe.ts, pe.width, pe.rssi,
	pe.ts - sc->dfs_prev_pulse_ts);
	sc->dfs_prev_pulse_ts = pe.ts;
	if (ard.pulse_bw_info & PRI_CH_RADAR_FOUND)
	ath9k_dfs_process_radar_pulse(sc, &pe);
	if (IS_CHAN_HT40(ah->curchan) &&
	ard.pulse_bw_info & EXT_CH_RADAR_FOUND) {
	pe.freq += IS_CHAN_HT40PLUS(ah->curchan) ? 20 : -20;
	ath9k_dfs_process_radar_pulse(sc, &pe);
	}
	}
	#undef PRI_CH_RADAR_FOUND
	#undef EXT_CH_RADAR_FOUND