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kernel/linux-rt-4.4.41/drivers/net/wireless/ath/ath9k/antenna.c 24.6 KB
5113f6f70   김현기   kernel add
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  /*
   * Copyright (c) 2012 Qualcomm Atheros, Inc.
   *
   * 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 "ath9k.h"
  
  /*
   * AR9285
   * ======
   *
   * EEPROM has 2 4-bit fields containing the card configuration.
   *
   * antdiv_ctl1:
   * ------------
   * bb_enable_ant_div_lnadiv : 1
   * bb_ant_div_alt_gaintb    : 1
   * bb_ant_div_main_gaintb   : 1
   * bb_enable_ant_fast_div   : 1
   *
   * antdiv_ctl2:
   * -----------
   * bb_ant_div_alt_lnaconf  : 2
   * bb_ant_div_main_lnaconf : 2
   *
   * The EEPROM bits are used as follows:
   * ------------------------------------
   *
   * bb_enable_ant_div_lnadiv      - Enable LNA path rx antenna diversity/combining.
   *                                 Set in AR_PHY_MULTICHAIN_GAIN_CTL.
   *
   * bb_ant_div_[alt/main]_gaintb  - 0 -> Antenna config Alt/Main uses gaintable 0
   *                                 1 -> Antenna config Alt/Main uses gaintable 1
   *                                 Set in AR_PHY_MULTICHAIN_GAIN_CTL.
   *
   * bb_enable_ant_fast_div        - Enable fast antenna diversity.
   *                                 Set in AR_PHY_CCK_DETECT.
   *
   * bb_ant_div_[alt/main]_lnaconf - Alt/Main LNA diversity/combining input config.
   *                                 Set in AR_PHY_MULTICHAIN_GAIN_CTL.
   *                                 10=LNA1
   *                                 01=LNA2
   *                                 11=LNA1+LNA2
   *                                 00=LNA1-LNA2
   *
   * AR9485 / AR9565 / AR9331
   * ========================
   *
   * The same bits are present in the EEPROM, but the location in the
   * EEPROM is different (ant_div_control in ar9300_BaseExtension_1).
   *
   * ant_div_alt_lnaconf      ==> bit 0~1
   * ant_div_main_lnaconf     ==> bit 2~3
   * ant_div_alt_gaintb       ==> bit 4
   * ant_div_main_gaintb      ==> bit 5
   * enable_ant_div_lnadiv    ==> bit 6
   * enable_ant_fast_div      ==> bit 7
   */
  
  static inline bool ath_is_alt_ant_ratio_better(struct ath_ant_comb *antcomb,
  					       int alt_ratio, int maxdelta,
  					       int mindelta, int main_rssi_avg,
  					       int alt_rssi_avg, int pkt_count)
  {
  	if (pkt_count <= 50)
  		return false;
  
  	if (alt_rssi_avg > main_rssi_avg + mindelta)
  		return true;
  
  	if (alt_ratio >= antcomb->ant_ratio2 &&
  	    alt_rssi_avg >= antcomb->low_rssi_thresh &&
  	    (alt_rssi_avg > main_rssi_avg + maxdelta))
  		return true;
  
  	return false;
  }
  
  static inline bool ath_ant_div_comb_alt_check(struct ath_hw_antcomb_conf *conf,
  					      struct ath_ant_comb *antcomb,
  					      int alt_ratio, int alt_rssi_avg,
  					      int main_rssi_avg)
  {
  	bool result, set1, set2;
  
  	result = set1 = set2 = false;
  
  	if (conf->main_lna_conf == ATH_ANT_DIV_COMB_LNA2 &&
  	    conf->alt_lna_conf == ATH_ANT_DIV_COMB_LNA1)
  		set1 = true;
  
  	if (conf->main_lna_conf == ATH_ANT_DIV_COMB_LNA1 &&
  	    conf->alt_lna_conf == ATH_ANT_DIV_COMB_LNA2)
  		set2 = true;
  
  	switch (conf->div_group) {
  	case 0:
  		if (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO)
  			result = true;
  		break;
  	case 1:
  	case 2:
  		if (alt_rssi_avg < 4 || alt_rssi_avg < antcomb->low_rssi_thresh)
  			break;
  
  		if ((set1 && (alt_rssi_avg >= (main_rssi_avg - 5))) ||
  		    (set2 && (alt_rssi_avg >= (main_rssi_avg - 2))) ||
  		    (alt_ratio > antcomb->ant_ratio))
  			result = true;
  
  		break;
  	case 3:
  		if (alt_rssi_avg < 4 || alt_rssi_avg < antcomb->low_rssi_thresh)
  			break;
  
  		if ((set1 && (alt_rssi_avg >= (main_rssi_avg - 3))) ||
  		    (set2 && (alt_rssi_avg >= (main_rssi_avg + 3))) ||
  		    (alt_ratio > antcomb->ant_ratio))
  			result = true;
  
  		break;
  	}
  
  	return result;
  }
  
  static void ath_lnaconf_alt_good_scan(struct ath_ant_comb *antcomb,
  				      struct ath_hw_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_ant_set_alt_ratio(struct ath_ant_comb *antcomb,
  				  struct ath_hw_antcomb_conf *conf)
  {
  	/* 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 (conf->main_lna_conf == ATH_ANT_DIV_COMB_LNA2)
  					conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA1;
  				else
  					conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA2;
  			else
  				/* Set alt to A+B or A-B */
  				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 (conf->main_lna_conf == ATH_ANT_DIV_COMB_LNA2)
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA1;
  			else
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA2;
  		} else {
  			/* Set alt to A+B or A-B */
  			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 (conf->main_lna_conf == ATH_ANT_DIV_COMB_LNA2)
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA1;
  			else
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA2;
  		else
  			/* Set alt to A+B or A-B */
  			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 (conf->main_lna_conf == ATH_ANT_DIV_COMB_LNA2)
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA1;
  			else
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA2;
  		else
  			/* Set alt to A+B or A-B */
  			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 (conf->main_lna_conf == ATH_ANT_DIV_COMB_LNA2)
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA1;
  			else
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA2;
  		else
  			/* Set alt to A+B or A-B */
  			conf->alt_lna_conf = antcomb->main_conf;
  	}
  }
  
  static void ath_select_ant_div_from_quick_scan(struct ath_ant_comb *antcomb,
  				       struct ath_hw_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(antcomb, 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 = true;
  			else
  				antcomb->first_ratio = false;
  		} else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2) {
  			if (ath_is_alt_ant_ratio_better(antcomb, 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 = true;
  			else
  				antcomb->first_ratio = false;
  		} else {
  			if (ath_is_alt_ant_ratio_better(antcomb, alt_ratio,
  						ATH_ANT_DIV_COMB_LNA1_DELTA_HI,
  						0,
  						main_rssi_avg, alt_rssi_avg,
  						antcomb->total_pkt_count))
  				antcomb->first_ratio = true;
  			else
  				antcomb->first_ratio = false;
  		}
  		break;
  	case 2:
  		antcomb->alt_good = false;
  		antcomb->scan_not_start = false;
  		antcomb->scan = false;
  		antcomb->rssi_first = main_rssi_avg;
  		antcomb->rssi_third = alt_rssi_avg;
  
  		switch(antcomb->second_quick_scan_conf) {
  		case ATH_ANT_DIV_COMB_LNA1:
  			antcomb->rssi_lna1 = alt_rssi_avg;
  			break;
  		case ATH_ANT_DIV_COMB_LNA2:
  			antcomb->rssi_lna2 = alt_rssi_avg;
  			break;
  		case 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;
  			break;
  		default:
  			break;
  		}
  
  		if (antcomb->rssi_lna2 > antcomb->rssi_lna1 +
  		    div_ant_conf->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(antcomb, 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 = true;
  			else
  				antcomb->second_ratio = false;
  		} else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2) {
  			if (ath_is_alt_ant_ratio_better(antcomb, 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 = true;
  			else
  				antcomb->second_ratio = false;
  		} else {
  			if (ath_is_alt_ant_ratio_better(antcomb, alt_ratio,
  						ATH_ANT_DIV_COMB_LNA1_DELTA_HI,
  						0,
  						main_rssi_avg, alt_rssi_avg,
  						antcomb->total_pkt_count))
  				antcomb->second_ratio = true;
  			else
  				antcomb->second_ratio = false;
  		}
  
  		ath_ant_set_alt_ratio(antcomb, div_ant_conf);
  
  		break;
  	default:
  		break;
  	}
  }
  
  static void ath_ant_div_conf_fast_divbias(struct ath_hw_antcomb_conf *ant_conf,
  					  struct ath_ant_comb *antcomb,
  					  int alt_ratio)
  {
  	ant_conf->main_gaintb = 0;
  	ant_conf->alt_gaintb = 0;
  
  	if (ant_conf->div_group == 0) {
  		/* 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;
  		}
  	} else if (ant_conf->div_group == 1) {
  		/* 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 = 0x1;
  			break;
  		case 0x02: /* A-B LNA1 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x03: /* A-B A+B */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x10: /* LNA2 A-B */
  			if (!(antcomb->scan) &&
  			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
  				ant_conf->fast_div_bias = 0x3f;
  			else
  				ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x12: /* LNA2 LNA1 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x13: /* LNA2 A+B */
  			if (!(antcomb->scan) &&
  			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
  				ant_conf->fast_div_bias = 0x3f;
  			else
  				ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x20: /* LNA1 A-B */
  			if (!(antcomb->scan) &&
  			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
  				ant_conf->fast_div_bias = 0x3f;
  			else
  				ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x21: /* LNA1 LNA2 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x23: /* LNA1 A+B */
  			if (!(antcomb->scan) &&
  			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
  				ant_conf->fast_div_bias = 0x3f;
  			else
  				ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x30: /* A+B A-B */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x31: /* A+B LNA2 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x32: /* A+B LNA1 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		default:
  			break;
  		}
  	} else if (ant_conf->div_group == 2) {
  		/* 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 = 0x1;
  			break;
  		case 0x02: /* A-B LNA1 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x03: /* A-B A+B */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x10: /* LNA2 A-B */
  			if (!antcomb->scan && (alt_ratio > antcomb->ant_ratio))
  				ant_conf->fast_div_bias = 0x1;
  			else
  				ant_conf->fast_div_bias = 0x2;
  			break;
  		case 0x12: /* LNA2 LNA1 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x13: /* LNA2 A+B */
  			if (!antcomb->scan && (alt_ratio > antcomb->ant_ratio))
  				ant_conf->fast_div_bias = 0x1;
  			else
  				ant_conf->fast_div_bias = 0x2;
  			break;
  		case 0x20: /* LNA1 A-B */
  			if (!antcomb->scan && (alt_ratio > antcomb->ant_ratio))
  				ant_conf->fast_div_bias = 0x1;
  			else
  				ant_conf->fast_div_bias = 0x2;
  			break;
  		case 0x21: /* LNA1 LNA2 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x23: /* LNA1 A+B */
  			if (!antcomb->scan && (alt_ratio > antcomb->ant_ratio))
  				ant_conf->fast_div_bias = 0x1;
  			else
  				ant_conf->fast_div_bias = 0x2;
  			break;
  		case 0x30: /* A+B A-B */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x31: /* A+B LNA2 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x32: /* A+B LNA1 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		default:
  			break;
  		}
  
  		if (antcomb->fast_div_bias)
  			ant_conf->fast_div_bias = antcomb->fast_div_bias;
  	} else if (ant_conf->div_group == 3) {
  		switch ((ant_conf->main_lna_conf << 4) |
  			ant_conf->alt_lna_conf) {
  		case 0x01: /* A-B LNA2 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x02: /* A-B LNA1 */
  			ant_conf->fast_div_bias = 0x39;
  			break;
  		case 0x03: /* A-B A+B */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x10: /* LNA2 A-B */
  			ant_conf->fast_div_bias = 0x2;
  			break;
  		case 0x12: /* LNA2 LNA1 */
  			ant_conf->fast_div_bias = 0x3f;
  			break;
  		case 0x13: /* LNA2 A+B */
  			ant_conf->fast_div_bias = 0x2;
  			break;
  		case 0x20: /* LNA1 A-B */
  			ant_conf->fast_div_bias = 0x3;
  			break;
  		case 0x21: /* LNA1 LNA2 */
  			ant_conf->fast_div_bias = 0x3;
  			break;
  		case 0x23: /* LNA1 A+B */
  			ant_conf->fast_div_bias = 0x3;
  			break;
  		case 0x30: /* A+B A-B */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		case 0x31: /* A+B LNA2 */
  			ant_conf->fast_div_bias = 0x6;
  			break;
  		case 0x32: /* A+B LNA1 */
  			ant_conf->fast_div_bias = 0x1;
  			break;
  		default:
  			break;
  		}
  	}
  }
  
  static void ath_ant_try_scan(struct ath_ant_comb *antcomb,
  			     struct ath_hw_antcomb_conf *conf,
  			     int curr_alt_set, int alt_rssi_avg,
  			     int main_rssi_avg)
  {
  	switch (curr_alt_set) {
  	case ATH_ANT_DIV_COMB_LNA2:
  		antcomb->rssi_lna2 = alt_rssi_avg;
  		antcomb->rssi_lna1 = main_rssi_avg;
  		antcomb->scan = true;
  		/* set to A+B */
  		conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA1;
  		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 = true;
  		/* set to A+B */
  		conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA2;
  		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 = true;
  		/* set to A-B */
  		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 = false;
  		if (antcomb->rssi_lna2 >
  		    (antcomb->rssi_lna1 + conf->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 */
  				conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA2;
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
  			} else if (antcomb->rssi_sub >
  				   antcomb->rssi_lna1) {
  				/* set to A-B */
  				conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA2;
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
  			} else {
  				/* set to LNA1 */
  				conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA2;
  				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 */
  				conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA1;
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
  			} else if (antcomb->rssi_sub >
  				   antcomb->rssi_lna1) {
  				/* set to A-B */
  				conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA1;
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
  			} else {
  				/* set to LNA2 */
  				conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA1;
  				conf->alt_lna_conf = ATH_ANT_DIV_COMB_LNA2;
  			}
  		}
  		break;
  	default:
  		break;
  	}
  }
  
  static bool ath_ant_try_switch(struct ath_hw_antcomb_conf *div_ant_conf,
  			       struct ath_ant_comb *antcomb,
  			       int alt_ratio, int alt_rssi_avg,
  			       int main_rssi_avg, int curr_main_set,
  			       int curr_alt_set)
  {
  	bool ret = false;
  
  	if (ath_ant_div_comb_alt_check(div_ant_conf, antcomb, alt_ratio,
  				       alt_rssi_avg, main_rssi_avg)) {
  		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;
  		}
  
  		ret = true;
  	} 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;
  
  		ret = true;
  	}
  
  	return ret;
  }
  
  static bool ath_ant_short_scan_check(struct ath_ant_comb *antcomb)
  {
  	int alt_ratio;
  
  	if (!antcomb->scan || !antcomb->alt_good)
  		return false;
  
  	if (time_after(jiffies, antcomb->scan_start_time +
  		       msecs_to_jiffies(ATH_ANT_DIV_COMB_SHORT_SCAN_INTR)))
  		return true;
  
  	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 < antcomb->ant_ratio)
  			return true;
  	}
  
  	return false;
  }
  
  void ath_ant_comb_scan(struct ath_softc *sc, struct ath_rx_status *rs)
  {
  	struct ath_hw_antcomb_conf div_ant_conf;
  	struct ath_ant_comb *antcomb = &sc->ant_comb;
  	int alt_ratio = 0, alt_rssi_avg = 0, main_rssi_avg = 0, curr_alt_set;
  	int curr_main_set;
  	int main_rssi = rs->rs_rssi_ctl[0];
  	int alt_rssi = rs->rs_rssi_ctl[1];
  	int rx_ant_conf,  main_ant_conf;
  	bool short_scan = false, ret;
  
  	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;
  
  	if (alt_rssi >= antcomb->low_rssi_thresh) {
  		antcomb->ant_ratio = ATH_ANT_DIV_COMB_ALT_ANT_RATIO;
  		antcomb->ant_ratio2 = ATH_ANT_DIV_COMB_ALT_ANT_RATIO2;
  	} else {
  		antcomb->ant_ratio = ATH_ANT_DIV_COMB_ALT_ANT_RATIO_LOW_RSSI;
  		antcomb->ant_ratio2 = ATH_ANT_DIV_COMB_ALT_ANT_RATIO2_LOW_RSSI;
  	}
  
  	/* Record packet only when both main_rssi and  alt_rssi is positive */
  	if (main_rssi > 0 && 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++;
  	}
  
  	if (main_ant_conf == rx_ant_conf) {
  		ANT_STAT_INC(ANT_MAIN, recv_cnt);
  		ANT_LNA_INC(ANT_MAIN, rx_ant_conf);
  	} else {
  		ANT_STAT_INC(ANT_ALT, recv_cnt);
  		ANT_LNA_INC(ANT_ALT, rx_ant_conf);
  	}
  
  	/* Short scan check */
  	short_scan = ath_ant_short_scan_check(antcomb);
  
  	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);
  	}
  
  	ath9k_hw_antdiv_comb_conf_get(sc->sc_ah, &div_ant_conf);
  	curr_alt_set = div_ant_conf.alt_lna_conf;
  	curr_main_set = div_ant_conf.main_lna_conf;
  	antcomb->count++;
  
  	if (antcomb->count == ATH_ANT_DIV_COMB_MAX_COUNT) {
  		if (alt_ratio > antcomb->ant_ratio) {
  			ath_lnaconf_alt_good_scan(antcomb, div_ant_conf,
  						  main_rssi_avg);
  			antcomb->alt_good = true;
  		} else {
  			antcomb->alt_good = false;
  		}
  
  		antcomb->count = 0;
  		antcomb->scan = true;
  		antcomb->scan_not_start = true;
  	}
  
  	if (!antcomb->scan) {
  		ret = ath_ant_try_switch(&div_ant_conf, antcomb, alt_ratio,
  					 alt_rssi_avg, main_rssi_avg,
  					 curr_main_set, curr_alt_set);
  		if (ret)
  			goto div_comb_done;
  	}
  
  	if (!antcomb->scan &&
  	    (alt_rssi_avg < (main_rssi_avg + div_ant_conf.lna1_lna2_delta)))
  		goto div_comb_done;
  
  	if (!antcomb->scan_not_start) {
  		ath_ant_try_scan(antcomb, &div_ant_conf, curr_alt_set,
  				 alt_rssi_avg, main_rssi_avg);
  	} else {
  		if (!antcomb->alt_good) {
  			antcomb->scan_not_start = 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, antcomb, alt_ratio);
  	ath9k_hw_antdiv_comb_conf_set(sc->sc_ah, &div_ant_conf);
  	ath9k_debug_stat_ant(sc, &div_ant_conf, main_rssi_avg, alt_rssi_avg);
  
  	antcomb->scan_start_time = jiffies;
  	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;
  }