Bring over the antenna diversity logic support for Kite.

Again, this is just the code ported from ath9k and included in the build,
it isn't yet enabled.

5 files changed, 687 insertions, 0 deletions

diff --git a/sys/conf/files b/sys/conf/files
index 315ea4e..5474399 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -775,6 +775,8 @@ dev/ath/ath_hal/ar9002/ar9285_cal.c optional ath_hal | ath_ar9285 \
 	compile-with "${NORMAL_C} -I$S/dev/ath -I$S/dev/ath/ath_hal"
 dev/ath/ath_hal/ar9002/ar9285_phy.c optional ath_hal | ath_ar9285 \ 
 	compile-with "${NORMAL_C} -I$S/dev/ath -I$S/dev/ath/ath_hal"
+dev/ath/ath_hal/ar9002/ar9285_diversity.c optional ath_hal | ath_ar9285 \ 
+	compile-with "${NORMAL_C} -I$S/dev/ath -I$S/dev/ath/ath_hal"
 # rf backends
 dev/ath/ath_hal/ar5212/ar2316.c	optional ath_rf2316 \
 	compile-with "${NORMAL_C} -I$S/dev/ath -I$S/dev/ath/ath_hal"
diff --git a/sys/dev/ath/ath_hal/ar9002/ar9285.h b/sys/dev/ath/ath_hal/ar9002/ar9285.h
index 39aab10..7e296a6 100644
--- a/sys/dev/ath/ath_hal/ar9002/ar9285.h
+++ b/sys/dev/ath/ath_hal/ar9002/ar9285.h
@@ -20,12 +20,49 @@
 
 #include "ar5416/ar5416.h"
 
+enum ar9285_ant_div_comb_lna_conf {
+	ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2,
+	ATH_ANT_DIV_COMB_LNA2,
+	ATH_ANT_DIV_COMB_LNA1,
+	ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2,
+};
+
+struct ar9285_ant_comb {
+	uint16_t count;
+	uint16_t total_pkt_count;
+	HAL_BOOL scan;
+	HAL_BOOL scan_not_start;
+	int main_total_rssi;
+	int alt_total_rssi;
+	int alt_recv_cnt;
+	int main_recv_cnt;
+	int rssi_lna1;
+	int rssi_lna2;
+	int rssi_add;
+	int rssi_sub;
+	int rssi_first;
+	int rssi_second;
+	int rssi_third;
+	HAL_BOOL alt_good;
+	int quick_scan_cnt;
+	int main_conf;
+	enum ar9285_ant_div_comb_lna_conf first_quick_scan_conf;
+	enum ar9285_ant_div_comb_lna_conf second_quick_scan_conf;
+	int first_bias;
+	int second_bias;
+	HAL_BOOL first_ratio;
+	HAL_BOOL second_ratio;
+	unsigned long scan_start_time;
+};
+
 struct ath_hal_9285 {
 	struct ath_hal_5416 ah_5416;
 
 	HAL_INI_ARRAY	ah_ini_txgain;
 	HAL_INI_ARRAY	ah_ini_rxgain;
 
+	struct ar9285_ant_comb ant_comb;	/* Kite Antenna comb/diversity */
+
 	struct {
 		int32_t prev_offset;	/* Previous value of PA offset value */
 		int8_t max_skipcount;	/* Max No. of times PACAL can be skipped */
diff --git a/sys/dev/ath/ath_hal/ar9002/ar9285_diversity.c b/sys/dev/ath/ath_hal/ar9002/ar9285_diversity.c
new file mode 100644
index 0000000..2901909
--- /dev/null
+++ b/sys/dev/ath/ath_hal/ar9002/ar9285_diversity.c
@@ -0,0 +1,594 @@
+/*
+ * Copyright (c) 2008-2010 Atheros Communications Inc.
+ * Copyright (c) 2011 Adrian Chadd, Xenion Pty Ltd.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+#include "opt_ah.h"
+
+#include "ah.h"
+#include "ah_desc.h"
+#include "ah_internal.h"
+#include "ah_eeprom_v4k.h"
+
+#include "ar9002/ar9280.h"
+#include "ar9002/ar9285_diversity.h"
+#include "ar9002/ar9285.h"
+#include "ar5416/ar5416reg.h"
+#include "ar5416/ar5416phy.h"
+#include "ar9002/ar9285phy.h"
+#include "ar9002/ar9285_phy.h"
+
+
+/* Linux compability macros */
+/*
+ * XXX these don't handle rounding, underflow, overflow, wrapping!
+ */
+#define	msecs_to_jiffies(a)		( (a) * hz / 1000 )
+#define	time_after(a, b)		( (long) (b) - (long) (a) < 0 )
+
+static HAL_BOOL
+ath_is_alt_ant_ratio_better(int alt_ratio, int maxdelta, int mindelta,
+    int main_rssi_avg, int alt_rssi_avg, int pkt_count)
+{
+	return (((alt_ratio >= ATH_ANT_DIV_COMB_ALT_ANT_RATIO2) &&
+		(alt_rssi_avg > main_rssi_avg + maxdelta)) ||
+		(alt_rssi_avg > main_rssi_avg + mindelta)) && (pkt_count > 50);
+}
+
+static void
+ath_lnaconf_alt_good_scan(struct ar9285_ant_comb *antcomb,
+    struct ar9285_antcomb_conf ant_conf, int main_rssi_avg)
+{
+	antcomb->quick_scan_cnt = 0;
+
+	if (ant_conf.main_lna_conf == ATH_ANT_DIV_COMB_LNA2)
+		antcomb->rssi_lna2 = main_rssi_avg;
+	else if (ant_conf.main_lna_conf == ATH_ANT_DIV_COMB_LNA1)
+		antcomb->rssi_lna1 = main_rssi_avg;
+
+	switch ((ant_conf.main_lna_conf << 4) | ant_conf.alt_lna_conf) {
+	case (0x10): /* LNA2 A-B */
+		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
+		antcomb->first_quick_scan_conf =
+			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
+		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA1;
+		break;
+	case (0x20): /* LNA1 A-B */
+		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
+		antcomb->first_quick_scan_conf =
+			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
+		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA2;
+		break;
+	case (0x21): /* LNA1 LNA2 */
+		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA2;
+		antcomb->first_quick_scan_conf =
+			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
+		antcomb->second_quick_scan_conf =
+			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
+		break;
+	case (0x12): /* LNA2 LNA1 */
+		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1;
+		antcomb->first_quick_scan_conf =
+			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
+		antcomb->second_quick_scan_conf =
+			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
+		break;
+	case (0x13): /* LNA2 A+B */
+		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
+		antcomb->first_quick_scan_conf =
+			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
+		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA1;
+		break;
+	case (0x23): /* LNA1 A+B */
+		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
+		antcomb->first_quick_scan_conf =
+			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
+		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA2;
+		break;
+	default:
+		break;
+	}
+}
+
+static void
+ath_select_ant_div_from_quick_scan(struct ar9285_ant_comb *antcomb,
+    struct ar9285_antcomb_conf *div_ant_conf, int main_rssi_avg,
+    int alt_rssi_avg, int alt_ratio)
+{
+	/* alt_good */
+	switch (antcomb->quick_scan_cnt) {
+	case 0:
+		/* set alt to main, and alt to first conf */
+		div_ant_conf->main_lna_conf = antcomb->main_conf;
+		div_ant_conf->alt_lna_conf = antcomb->first_quick_scan_conf;
+		break;
+	case 1:
+		/* set alt to main, and alt to first conf */
+		div_ant_conf->main_lna_conf = antcomb->main_conf;
+		div_ant_conf->alt_lna_conf = antcomb->second_quick_scan_conf;
+		antcomb->rssi_first = main_rssi_avg;
+		antcomb->rssi_second = alt_rssi_avg;
+
+		if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1) {
+			/* main is LNA1 */
+			if (ath_is_alt_ant_ratio_better(alt_ratio,
+						ATH_ANT_DIV_COMB_LNA1_DELTA_HI,
+						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
+						main_rssi_avg, alt_rssi_avg,
+						antcomb->total_pkt_count))
+				antcomb->first_ratio = AH_TRUE;
+			else
+				antcomb->first_ratio = AH_FALSE;
+		} else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2) {
+			if (ath_is_alt_ant_ratio_better(alt_ratio,
+						ATH_ANT_DIV_COMB_LNA1_DELTA_MID,
+						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
+						main_rssi_avg, alt_rssi_avg,
+						antcomb->total_pkt_count))
+				antcomb->first_ratio = AH_TRUE;
+			else
+				antcomb->first_ratio = AH_FALSE;
+		} else {
+			if ((((alt_ratio >= ATH_ANT_DIV_COMB_ALT_ANT_RATIO2) &&
+			    (alt_rssi_avg > main_rssi_avg +
+			    ATH_ANT_DIV_COMB_LNA1_DELTA_HI)) ||
+			    (alt_rssi_avg > main_rssi_avg)) &&
+			    (antcomb->total_pkt_count > 50))
+				antcomb->first_ratio = AH_TRUE;
+			else
+				antcomb->first_ratio = AH_FALSE;
+		}
+		break;
+	case 2:
+		antcomb->alt_good = AH_FALSE;
+		antcomb->scan_not_start = AH_FALSE;
+		antcomb->scan = AH_FALSE;
+		antcomb->rssi_first = main_rssi_avg;
+		antcomb->rssi_third = alt_rssi_avg;
+
+		if (antcomb->second_quick_scan_conf == ATH_ANT_DIV_COMB_LNA1)
+			antcomb->rssi_lna1 = alt_rssi_avg;
+		else if (antcomb->second_quick_scan_conf ==
+			 ATH_ANT_DIV_COMB_LNA2)
+			antcomb->rssi_lna2 = alt_rssi_avg;
+		else if (antcomb->second_quick_scan_conf ==
+			 ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2) {
+			if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2)
+				antcomb->rssi_lna2 = main_rssi_avg;
+			else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1)
+				antcomb->rssi_lna1 = main_rssi_avg;
+		}
+
+		if (antcomb->rssi_lna2 > antcomb->rssi_lna1 +
+		    ATH_ANT_DIV_COMB_LNA1_LNA2_SWITCH_DELTA)
+			div_ant_conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA2;
+		else
+			div_ant_conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA1;
+
+		if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1) {
+			if (ath_is_alt_ant_ratio_better(alt_ratio,
+						ATH_ANT_DIV_COMB_LNA1_DELTA_HI,
+						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
+						main_rssi_avg, alt_rssi_avg,
+						antcomb->total_pkt_count))
+				antcomb->second_ratio = AH_TRUE;
+			else
+				antcomb->second_ratio = AH_FALSE;
+		} else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2) {
+			if (ath_is_alt_ant_ratio_better(alt_ratio,
+						ATH_ANT_DIV_COMB_LNA1_DELTA_MID,
+						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
+						main_rssi_avg, alt_rssi_avg,
+						antcomb->total_pkt_count))
+				antcomb->second_ratio = AH_TRUE;
+			else
+				antcomb->second_ratio = AH_FALSE;
+		} else {
+			if ((((alt_ratio >= ATH_ANT_DIV_COMB_ALT_ANT_RATIO2) &&
+			    (alt_rssi_avg > main_rssi_avg +
+			    ATH_ANT_DIV_COMB_LNA1_DELTA_HI)) ||
+			    (alt_rssi_avg > main_rssi_avg)) &&
+			    (antcomb->total_pkt_count > 50))
+				antcomb->second_ratio = AH_TRUE;
+			else
+				antcomb->second_ratio = AH_FALSE;
+		}
+
+		/* set alt to the conf with maximun ratio */
+		if (antcomb->first_ratio && antcomb->second_ratio) {
+			if (antcomb->rssi_second > antcomb->rssi_third) {
+				/* first alt*/
+				if ((antcomb->first_quick_scan_conf ==
+				    ATH_ANT_DIV_COMB_LNA1) ||
+				    (antcomb->first_quick_scan_conf ==
+				    ATH_ANT_DIV_COMB_LNA2))
+					/* Set alt LNA1 or LNA2*/
+					if (div_ant_conf->main_lna_conf ==
+					    ATH_ANT_DIV_COMB_LNA2)
+						div_ant_conf->alt_lna_conf =
+							ATH_ANT_DIV_COMB_LNA1;
+					else
+						div_ant_conf->alt_lna_conf =
+							ATH_ANT_DIV_COMB_LNA2;
+				else
+					/* Set alt to A+B or A-B */
+					div_ant_conf->alt_lna_conf =
+						antcomb->first_quick_scan_conf;
+			} else if ((antcomb->second_quick_scan_conf ==
+				   ATH_ANT_DIV_COMB_LNA1) ||
+				   (antcomb->second_quick_scan_conf ==
+				   ATH_ANT_DIV_COMB_LNA2)) {
+				/* Set alt LNA1 or LNA2 */
+				if (div_ant_conf->main_lna_conf ==
+				    ATH_ANT_DIV_COMB_LNA2)
+					div_ant_conf->alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1;
+				else
+					div_ant_conf->alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA2;
+			} else {
+				/* Set alt to A+B or A-B */
+				div_ant_conf->alt_lna_conf =
+					antcomb->second_quick_scan_conf;
+			}
+		} else if (antcomb->first_ratio) {
+			/* first alt */
+			if ((antcomb->first_quick_scan_conf ==
+			    ATH_ANT_DIV_COMB_LNA1) ||
+			    (antcomb->first_quick_scan_conf ==
+			    ATH_ANT_DIV_COMB_LNA2))
+					/* Set alt LNA1 or LNA2 */
+				if (div_ant_conf->main_lna_conf ==
+				    ATH_ANT_DIV_COMB_LNA2)
+					div_ant_conf->alt_lna_conf =
+							ATH_ANT_DIV_COMB_LNA1;
+				else
+					div_ant_conf->alt_lna_conf =
+							ATH_ANT_DIV_COMB_LNA2;
+			else
+				/* Set alt to A+B or A-B */
+				div_ant_conf->alt_lna_conf =
+						antcomb->first_quick_scan_conf;
+		} else if (antcomb->second_ratio) {
+				/* second alt */
+			if ((antcomb->second_quick_scan_conf ==
+			    ATH_ANT_DIV_COMB_LNA1) ||
+			    (antcomb->second_quick_scan_conf ==
+			    ATH_ANT_DIV_COMB_LNA2))
+				/* Set alt LNA1 or LNA2 */
+				if (div_ant_conf->main_lna_conf ==
+				    ATH_ANT_DIV_COMB_LNA2)
+					div_ant_conf->alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1;
+				else
+					div_ant_conf->alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA2;
+			else
+				/* Set alt to A+B or A-B */
+				div_ant_conf->alt_lna_conf =
+						antcomb->second_quick_scan_conf;
+		} else {
+			/* main is largest */
+			if ((antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1) ||
+			    (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2))
+				/* Set alt LNA1 or LNA2 */
+				if (div_ant_conf->main_lna_conf ==
+				    ATH_ANT_DIV_COMB_LNA2)
+					div_ant_conf->alt_lna_conf =
+							ATH_ANT_DIV_COMB_LNA1;
+				else
+					div_ant_conf->alt_lna_conf =
+							ATH_ANT_DIV_COMB_LNA2;
+			else
+				/* Set alt to A+B or A-B */
+				div_ant_conf->alt_lna_conf = antcomb->main_conf;
+		}
+		break;
+	default:
+		break;
+	}
+}
+
+static void
+ath_ant_div_conf_fast_divbias(struct ar9285_antcomb_conf *ant_conf)
+{
+	/* Adjust the fast_div_bias based on main and alt lna conf */
+	switch ((ant_conf->main_lna_conf << 4) | ant_conf->alt_lna_conf) {
+	case (0x01): /* A-B LNA2 */
+		ant_conf->fast_div_bias = 0x3b;
+		break;
+	case (0x02): /* A-B LNA1 */
+		ant_conf->fast_div_bias = 0x3d;
+		break;
+	case (0x03): /* A-B A+B */
+		ant_conf->fast_div_bias = 0x1;
+		break;
+	case (0x10): /* LNA2 A-B */
+		ant_conf->fast_div_bias = 0x7;
+		break;
+	case (0x12): /* LNA2 LNA1 */
+		ant_conf->fast_div_bias = 0x2;
+		break;
+	case (0x13): /* LNA2 A+B */
+		ant_conf->fast_div_bias = 0x7;
+		break;
+	case (0x20): /* LNA1 A-B */
+		ant_conf->fast_div_bias = 0x6;
+		break;
+	case (0x21): /* LNA1 LNA2 */
+		ant_conf->fast_div_bias = 0x0;
+		break;
+	case (0x23): /* LNA1 A+B */
+		ant_conf->fast_div_bias = 0x6;
+		break;
+	case (0x30): /* A+B A-B */
+		ant_conf->fast_div_bias = 0x1;
+		break;
+	case (0x31): /* A+B LNA2 */
+		ant_conf->fast_div_bias = 0x3b;
+		break;
+	case (0x32): /* A+B LNA1 */
+		ant_conf->fast_div_bias = 0x3d;
+		break;
+	default:
+		break;
+	}
+}
+
+/* Antenna diversity and combining */
+void
+ar9285_ant_comb_scan(struct ath_hal *ah, struct ath_rx_status *rs,
+    unsigned long ticks, int hz)
+{
+	struct ar9285_antcomb_conf div_ant_conf;
+	struct ar9285_ant_comb *antcomb = &AH9285(ah)->ant_comb;
+	int alt_ratio = 0, alt_rssi_avg = 0, main_rssi_avg = 0, curr_alt_set;
+	int curr_main_set, curr_bias;
+	int main_rssi = rs->rs_rssi_ctl[0];
+	int alt_rssi = rs->rs_rssi_ctl[1];
+	int rx_ant_conf, main_ant_conf;
+	HAL_BOOL short_scan = AH_FALSE;
+
+	rx_ant_conf = (rs->rs_rssi_ctl[2] >> ATH_ANT_RX_CURRENT_SHIFT) &
+		       ATH_ANT_RX_MASK;
+	main_ant_conf = (rs->rs_rssi_ctl[2] >> ATH_ANT_RX_MAIN_SHIFT) &
+			 ATH_ANT_RX_MASK;
+
+	/* Record packet only when alt_rssi is positive */
+	if (alt_rssi > 0) {
+		antcomb->total_pkt_count++;
+		antcomb->main_total_rssi += main_rssi;
+		antcomb->alt_total_rssi  += alt_rssi;
+		if (main_ant_conf == rx_ant_conf)
+			antcomb->main_recv_cnt++;
+		else
+			antcomb->alt_recv_cnt++;
+	}
+
+	/* Short scan check */
+	if (antcomb->scan && antcomb->alt_good) {
+		if (time_after(ticks, antcomb->scan_start_time +
+		    msecs_to_jiffies(ATH_ANT_DIV_COMB_SHORT_SCAN_INTR)))
+			short_scan = AH_TRUE;
+		else
+			if (antcomb->total_pkt_count ==
+			    ATH_ANT_DIV_COMB_SHORT_SCAN_PKTCOUNT) {
+				alt_ratio = ((antcomb->alt_recv_cnt * 100) /
+					    antcomb->total_pkt_count);
+				if (alt_ratio < ATH_ANT_DIV_COMB_ALT_ANT_RATIO)
+					short_scan = AH_TRUE;
+			}
+	}
+
+	if (((antcomb->total_pkt_count < ATH_ANT_DIV_COMB_MAX_PKTCOUNT) ||
+	    rs->rs_moreaggr) && !short_scan)
+		return;
+
+	if (antcomb->total_pkt_count) {
+		alt_ratio = ((antcomb->alt_recv_cnt * 100) /
+			     antcomb->total_pkt_count);
+		main_rssi_avg = (antcomb->main_total_rssi /
+				 antcomb->total_pkt_count);
+		alt_rssi_avg = (antcomb->alt_total_rssi /
+				 antcomb->total_pkt_count);
+	}
+
+
+	ar9285_antdiv_comb_conf_get(ah, &div_ant_conf);
+	curr_alt_set = div_ant_conf.alt_lna_conf;
+	curr_main_set = div_ant_conf.main_lna_conf;
+	curr_bias = div_ant_conf.fast_div_bias;
+
+	antcomb->count++;
+
+	if (antcomb->count == ATH_ANT_DIV_COMB_MAX_COUNT) {
+		if (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO) {
+			ath_lnaconf_alt_good_scan(antcomb, div_ant_conf,
+						  main_rssi_avg);
+			antcomb->alt_good = AH_TRUE;
+		} else {
+			antcomb->alt_good = AH_FALSE;
+		}
+
+		antcomb->count = 0;
+		antcomb->scan = AH_TRUE;
+		antcomb->scan_not_start = AH_TRUE;
+	}
+
+	if (!antcomb->scan) {
+		if (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO) {
+			if (curr_alt_set == ATH_ANT_DIV_COMB_LNA2) {
+				/* Switch main and alt LNA */
+				div_ant_conf.main_lna_conf =
+						ATH_ANT_DIV_COMB_LNA2;
+				div_ant_conf.alt_lna_conf  =
+						ATH_ANT_DIV_COMB_LNA1;
+			} else if (curr_alt_set == ATH_ANT_DIV_COMB_LNA1) {
+				div_ant_conf.main_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1;
+				div_ant_conf.alt_lna_conf  =
+						ATH_ANT_DIV_COMB_LNA2;
+			}
+
+			goto div_comb_done;
+		} else if ((curr_alt_set != ATH_ANT_DIV_COMB_LNA1) &&
+			   (curr_alt_set != ATH_ANT_DIV_COMB_LNA2)) {
+			/* Set alt to another LNA */
+			if (curr_main_set == ATH_ANT_DIV_COMB_LNA2)
+				div_ant_conf.alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1;
+			else if (curr_main_set == ATH_ANT_DIV_COMB_LNA1)
+				div_ant_conf.alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA2;
+
+			goto div_comb_done;
+		}
+
+		if ((alt_rssi_avg < (main_rssi_avg +
+		    ATH_ANT_DIV_COMB_LNA1_LNA2_DELTA)))
+			goto div_comb_done;
+	}
+
+	if (!antcomb->scan_not_start) {
+		switch (curr_alt_set) {
+		case ATH_ANT_DIV_COMB_LNA2:
+			antcomb->rssi_lna2 = alt_rssi_avg;
+			antcomb->rssi_lna1 = main_rssi_avg;
+			antcomb->scan = AH_TRUE;
+			/* set to A+B */
+			div_ant_conf.main_lna_conf =
+				ATH_ANT_DIV_COMB_LNA1;
+			div_ant_conf.alt_lna_conf  =
+				ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
+			break;
+		case ATH_ANT_DIV_COMB_LNA1:
+			antcomb->rssi_lna1 = alt_rssi_avg;
+			antcomb->rssi_lna2 = main_rssi_avg;
+			antcomb->scan = AH_TRUE;
+			/* set to A+B */
+			div_ant_conf.main_lna_conf = ATH_ANT_DIV_COMB_LNA2;
+			div_ant_conf.alt_lna_conf  =
+				ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
+			break;
+		case ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2:
+			antcomb->rssi_add = alt_rssi_avg;
+			antcomb->scan = AH_TRUE;
+			/* set to A-B */
+			div_ant_conf.alt_lna_conf =
+				ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
+			break;
+		case ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2:
+			antcomb->rssi_sub = alt_rssi_avg;
+			antcomb->scan = AH_FALSE;
+			if (antcomb->rssi_lna2 >
+			    (antcomb->rssi_lna1 +
+			    ATH_ANT_DIV_COMB_LNA1_LNA2_SWITCH_DELTA)) {
+				/* use LNA2 as main LNA */
+				if ((antcomb->rssi_add > antcomb->rssi_lna1) &&
+				    (antcomb->rssi_add > antcomb->rssi_sub)) {
+					/* set to A+B */
+					div_ant_conf.main_lna_conf =
+						ATH_ANT_DIV_COMB_LNA2;
+					div_ant_conf.alt_lna_conf  =
+						ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
+				} else if (antcomb->rssi_sub >
+					   antcomb->rssi_lna1) {
+					/* set to A-B */
+					div_ant_conf.main_lna_conf =
+						ATH_ANT_DIV_COMB_LNA2;
+					div_ant_conf.alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
+				} else {
+					/* set to LNA1 */
+					div_ant_conf.main_lna_conf =
+						ATH_ANT_DIV_COMB_LNA2;
+					div_ant_conf.alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1;
+				}
+			} else {
+				/* use LNA1 as main LNA */
+				if ((antcomb->rssi_add > antcomb->rssi_lna2) &&
+				    (antcomb->rssi_add > antcomb->rssi_sub)) {
+					/* set to A+B */
+					div_ant_conf.main_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1;
+					div_ant_conf.alt_lna_conf  =
+						ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
+				} else if (antcomb->rssi_sub >
+					   antcomb->rssi_lna1) {
+					/* set to A-B */
+					div_ant_conf.main_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1;
+					div_ant_conf.alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
+				} else {
+					/* set to LNA2 */
+					div_ant_conf.main_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1;
+					div_ant_conf.alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA2;
+				}
+			}
+			break;
+		default:
+			break;
+		}
+	} else {
+		if (!antcomb->alt_good) {
+			antcomb->scan_not_start = AH_FALSE;
+			/* Set alt to another LNA */
+			if (curr_main_set == ATH_ANT_DIV_COMB_LNA2) {
+				div_ant_conf.main_lna_conf =
+						ATH_ANT_DIV_COMB_LNA2;
+				div_ant_conf.alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1;
+			} else if (curr_main_set == ATH_ANT_DIV_COMB_LNA1) {
+				div_ant_conf.main_lna_conf =
+						ATH_ANT_DIV_COMB_LNA1;
+				div_ant_conf.alt_lna_conf =
+						ATH_ANT_DIV_COMB_LNA2;
+			}
+			goto div_comb_done;
+		}
+	}
+
+	ath_select_ant_div_from_quick_scan(antcomb, &div_ant_conf,
+					   main_rssi_avg, alt_rssi_avg,
+					   alt_ratio);
+
+	antcomb->quick_scan_cnt++;
+
+div_comb_done:
+	ath_ant_div_conf_fast_divbias(&div_ant_conf);
+
+	ar9285_antdiv_comb_conf_set(ah, &div_ant_conf);
+
+	antcomb->scan_start_time = ticks;
+	antcomb->total_pkt_count = 0;
+	antcomb->main_total_rssi = 0;
+	antcomb->alt_total_rssi = 0;
+	antcomb->main_recv_cnt = 0;
+	antcomb->alt_recv_cnt = 0;
+}
diff --git a/sys/dev/ath/ath_hal/ar9002/ar9285_diversity.h b/sys/dev/ath/ath_hal/ar9002/ar9285_diversity.h
new file mode 100644
index 0000000..220db1e
--- /dev/null
+++ b/sys/dev/ath/ath_hal/ar9002/ar9285_diversity.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2008-2010 Atheros Communications Inc.
+ * Copyright (c) 2011 Adrian Chadd, Xenion Pty Ltd.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+#ifndef	__AR9285_DIVERSITY_H__
+#define	__AR9285_DIVERSITY_H__
+
+/* Antenna diversity/combining */
+#define	ATH_ANT_RX_CURRENT_SHIFT	4
+#define	ATH_ANT_RX_MAIN_SHIFT		2
+#define	ATH_ANT_RX_MASK			0x3
+
+#define	ATH_ANT_DIV_COMB_SHORT_SCAN_INTR	50
+#define	ATH_ANT_DIV_COMB_SHORT_SCAN_PKTCOUNT	0x100
+#define	ATH_ANT_DIV_COMB_MAX_PKTCOUNT		0x200
+#define	ATH_ANT_DIV_COMB_INIT_COUNT		95
+#define	ATH_ANT_DIV_COMB_MAX_COUNT		100
+#define	ATH_ANT_DIV_COMB_ALT_ANT_RATIO		30
+#define	ATH_ANT_DIV_COMB_ALT_ANT_RATIO2		20
+
+#define	ATH_ANT_DIV_COMB_LNA1_LNA2_DELTA	-3
+#define	ATH_ANT_DIV_COMB_LNA1_LNA2_SWITCH_DELTA	-1
+#define	ATH_ANT_DIV_COMB_LNA1_DELTA_HI		-4
+#define	ATH_ANT_DIV_COMB_LNA1_DELTA_MID		-2
+#define	ATH_ANT_DIV_COMB_LNA1_DELTA_LOW		2
+
+extern	void ar9285_ant_comb_scan(struct ath_hal *ah, struct ath_rx_status *rs,
+		unsigned long ticks, int hz);
+
+#endif
diff --git a/sys/modules/ath/Makefile b/sys/modules/ath/Makefile
index 69d785a..e5fc7f6 100644
--- a/sys/modules/ath/Makefile
+++ b/sys/modules/ath/Makefile
@@ -99,6 +99,7 @@ SRCS+=	ar9160_attach.c
 .PATH:	${.CURDIR}/../../dev/ath/ath_hal/ar9002
 SRCS+=	ar9280.c ar9280_attach.c ar9280_olc.c
 SRCS+=	ar9285.c ar9285_reset.c ar9285_attach.c ar9285_cal.c ar9285_phy.c
+SRCS+=	ar9285_diversity.c
 
 # NB: rate control is bound to the driver by symbol names so only pick one
 .if ${ATH_RATE} == "sample"