1 files changed, 361 insertions, 0 deletions
diff --git a/drivers/net/wireless/ath/ath9k/dfs.c b/drivers/net/wireless/ath/ath9k/dfs.c
new file mode 100644
index 0000000..acb9602
--- /dev/null
+++ b/drivers/net/wireless/ath/ath9k/dfs.c
@@ -0,0 +1,361 @@
+/*
+ * 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 = (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;
+	}
+
+	/* 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);
+}
+
+/*
+ * 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