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

 /*
  * Copyright (c) 2008-2011 Atheros Communications 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 "hw.h"
 #include "hw-ops.h"

 /* Common calibration code */

 #define ATH9K_NF_TOO_HIGH	-60

 static int16_t ath9k_hw_get_nf_hist_mid(int16_t *nfCalBuffer)
 {
 	int16_t nfval;
 	int16_t sort[ATH9K_NF_CAL_HIST_MAX];
 	int i, j;

 	for (i = 0; i < ATH9K_NF_CAL_HIST_MAX; i++)
 		sort[i] = nfCalBuffer[i];

 	for (i = 0; i < ATH9K_NF_CAL_HIST_MAX - 1; i++) {
 		for (j = 1; j < ATH9K_NF_CAL_HIST_MAX - i; j++) {
 			if (sort[j] > sort[j - 1]) {
 				nfval = sort[j];
 				sort[j] = sort[j - 1];
 				sort[j - 1] = nfval;
 			}
 		}
 	}
 	nfval = sort[(ATH9K_NF_CAL_HIST_MAX - 1) >> 1];

 	return nfval;
 }

 static struct ath_nf_limits *ath9k_hw_get_nf_limits(struct ath_hw *ah,
 						    struct ath9k_channel *chan)
 {
 	struct ath_nf_limits *limit;

 	if (!chan || IS_CHAN_2GHZ(chan))
 		limit = &ah->nf_2g;
 	else
 		limit = &ah->nf_5g;

 	return limit;
 }

 static s16 ath9k_hw_get_default_nf(struct ath_hw *ah,
 				   struct ath9k_channel *chan)
 {
 	return ath9k_hw_get_nf_limits(ah, chan)->nominal;
 }


 static void ath9k_hw_update_nfcal_hist_buffer(struct ath_hw *ah,
 					      struct ath9k_hw_cal_data *cal,
 					      int16_t *nfarray)
 {
 	struct ath_common *common = ath9k_hw_common(ah);
 	struct ieee80211_conf *conf = &common->hw->conf;
 	struct ath_nf_limits *limit;
 	struct ath9k_nfcal_hist *h;
 	bool high_nf_mid = false;
 	u8 chainmask = (ah->rxchainmask << 3) | ah->rxchainmask;
 	int i;

 	h = cal->nfCalHist;
 	limit = ath9k_hw_get_nf_limits(ah, ah->curchan);

 	for (i = 0; i < NUM_NF_READINGS; i++) {
 		if (!(chainmask & (1 << i)) ||
 		    ((i >= AR5416_MAX_CHAINS) && !conf_is_ht40(conf)))
 			continue;

 		h[i].nfCalBuffer[h[i].currIndex] = nfarray[i];

 		if (++h[i].currIndex >= ATH9K_NF_CAL_HIST_MAX)
 			h[i].currIndex = 0;

 		if (h[i].invalidNFcount > 0) {
 			h[i].invalidNFcount--;
 			h[i].privNF = nfarray[i];
 		} else {
 			h[i].privNF =
 				ath9k_hw_get_nf_hist_mid(h[i].nfCalBuffer);
 		}

 		if (!h[i].privNF)
 			continue;

 		if (h[i].privNF > limit->max) {
 			high_nf_mid = true;

 			ath_dbg(common, ATH_DBG_CALIBRATE,
 				"NFmid[%d] (%d) > MAX (%d), %s\n",
 				i, h[i].privNF, limit->max,
 				(cal->nfcal_interference ?
 				 "not corrected (due to interference)" :
 				 "correcting to MAX"));

 			/*
 			 * Normally we limit the average noise floor by the
 			 * hardware specific maximum here. However if we have
 			 * encountered stuck beacons because of interference,
 			 * we bypass this limit here in order to better deal
 			 * with our environment.
 			 */
 			if (!cal->nfcal_interference)
 				h[i].privNF = limit->max;
 		}
 	}

 	/*
 	 * If the noise floor seems normal for all chains, assume that
 	 * there is no significant interference in the environment anymore.
 	 * Re-enable the enforcement of the NF maximum again.
 	 */
 	if (!high_nf_mid)
 		cal->nfcal_interference = false;
 }

 static bool ath9k_hw_get_nf_thresh(struct ath_hw *ah,
 				   enum ieee80211_band band,
 				   int16_t *nft)
 {
 	switch (band) {
 	case IEEE80211_BAND_5GHZ:
 		*nft = (int8_t)ah->eep_ops->get_eeprom(ah, EEP_NFTHRESH_5);
 		break;
 	case IEEE80211_BAND_2GHZ:
 		*nft = (int8_t)ah->eep_ops->get_eeprom(ah, EEP_NFTHRESH_2);
 		break;
 	default:
 		BUG_ON(1);
 		return false;
 	}

 	return true;
 }

 void ath9k_hw_reset_calibration(struct ath_hw *ah,
 				struct ath9k_cal_list *currCal)
 {
 	int i;

 	ath9k_hw_setup_calibration(ah, currCal);

 	currCal->calState = CAL_RUNNING;

 	for (i = 0; i < AR5416_MAX_CHAINS; i++) {
 		ah->meas0.sign[i] = 0;
 		ah->meas1.sign[i] = 0;
 		ah->meas2.sign[i] = 0;
 		ah->meas3.sign[i] = 0;
 	}

 	ah->cal_samples = 0;
 }

 /* This is done for the currently configured channel */
 bool ath9k_hw_reset_calvalid(struct ath_hw *ah)
 {
 	struct ath_common *common = ath9k_hw_common(ah);
 	struct ieee80211_conf *conf = &common->hw->conf;
 	struct ath9k_cal_list *currCal = ah->cal_list_curr;

 	if (!ah->caldata)
 		return true;

 	if (!AR_SREV_9100(ah) && !AR_SREV_9160_10_OR_LATER(ah))
 		return true;

 	if (currCal == NULL)
 		return true;

 	if (currCal->calState != CAL_DONE) {
 		ath_dbg(common, ATH_DBG_CALIBRATE,
 			"Calibration state incorrect, %d\n",
 			currCal->calState);
 		return true;
 	}

 	if (!(ah->supp_cals & currCal->calData->calType))
 		return true;

 	ath_dbg(common, ATH_DBG_CALIBRATE,
 		"Resetting Cal %d state for channel %u\n",
 		currCal->calData->calType, conf->channel->center_freq);

 	ah->caldata->CalValid &= ~currCal->calData->calType;
 	currCal->calState = CAL_WAITING;

 	return false;
 }
 EXPORT_SYMBOL(ath9k_hw_reset_calvalid);

 void ath9k_hw_start_nfcal(struct ath_hw *ah, bool update)
 {
 	if (ah->caldata)
 		ah->caldata->nfcal_pending = true;

 	REG_SET_BIT(ah, AR_PHY_AGC_CONTROL,
 		    AR_PHY_AGC_CONTROL_ENABLE_NF);

 	if (update)
 		REG_CLR_BIT(ah, AR_PHY_AGC_CONTROL,
 		    AR_PHY_AGC_CONTROL_NO_UPDATE_NF);
 	else
 		REG_SET_BIT(ah, AR_PHY_AGC_CONTROL,
 		    AR_PHY_AGC_CONTROL_NO_UPDATE_NF);

 	REG_SET_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_NF);
 }

 void ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan)
 {
 	struct ath9k_nfcal_hist *h = NULL;
 	unsigned i, j;
 	int32_t val;
 	u8 chainmask = (ah->rxchainmask << 3) | ah->rxchainmask;
 	struct ath_common *common = ath9k_hw_common(ah);
 	struct ieee80211_conf *conf = &common->hw->conf;
 	s16 default_nf = ath9k_hw_get_default_nf(ah, chan);

 	if (ah->caldata)
 		h = ah->caldata->nfCalHist;

 	for (i = 0; i < NUM_NF_READINGS; i++) {
 		if (chainmask & (1 << i)) {
 			s16 nfval;

 			if ((i >= AR5416_MAX_CHAINS) && !conf_is_ht40(conf))
 				continue;

 			if (h)
 				nfval = h[i].privNF;
 			else
 				nfval = default_nf;

 			val = REG_READ(ah, ah->nf_regs[i]);
 			val &= 0xFFFFFE00;
 			val |= (((u32) nfval << 1) & 0x1ff);
 			REG_WRITE(ah, ah->nf_regs[i], val);
 		}
 	}

 	/*
 	 * Load software filtered NF value into baseband internal minCCApwr
 	 * variable.
 	 */
 	REG_CLR_BIT(ah, AR_PHY_AGC_CONTROL,
 		    AR_PHY_AGC_CONTROL_ENABLE_NF);
 	REG_CLR_BIT(ah, AR_PHY_AGC_CONTROL,
 		    AR_PHY_AGC_CONTROL_NO_UPDATE_NF);
 	REG_SET_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_NF);

 	/*
 	 * Wait for load to complete, should be fast, a few 10s of us.
 	 * The max delay was changed from an original 250us to 10000us
 	 * since 250us often results in NF load timeout and causes deaf
 	 * condition during stress testing 12/12/2009
 	 */
 	for (j = 0; j < 10000; j++) {
 		if ((REG_READ(ah, AR_PHY_AGC_CONTROL) &
 		     AR_PHY_AGC_CONTROL_NF) == 0)
 			break;
 		udelay(10);
 	}

 	/*
 	 * We timed out waiting for the noisefloor to load, probably due to an
 	 * in-progress rx. Simply return here and allow the load plenty of time
 	 * to complete before the next calibration interval.  We need to avoid
 	 * trying to load -50 (which happens below) while the previous load is
 	 * still in progress as this can cause rx deafness. Instead by returning
 	 * here, the baseband nf cal will just be capped by our present
 	 * noisefloor until the next calibration timer.
 	 */
 	if (j == 10000) {
 		ath_dbg(common, ATH_DBG_ANY,
 			"Timeout while waiting for nf to load: AR_PHY_AGC_CONTROL=0x%x\n",
 			REG_READ(ah, AR_PHY_AGC_CONTROL));
 		return;
 	}

 	/*
 	 * Restore maxCCAPower register parameter again so that we're not capped
 	 * by the median we just loaded.  This will be initial (and max) value
 	 * of next noise floor calibration the baseband does.
 	 */
 	ENABLE_REGWRITE_BUFFER(ah);
 	for (i = 0; i < NUM_NF_READINGS; i++) {
 		if (chainmask & (1 << i)) {
 			if ((i >= AR5416_MAX_CHAINS) && !conf_is_ht40(conf))
 				continue;

 			val = REG_READ(ah, ah->nf_regs[i]);
 			val &= 0xFFFFFE00;
 			val |= (((u32) (-50) << 1) & 0x1ff);
 			REG_WRITE(ah, ah->nf_regs[i], val);
 		}
 	}
 	REGWRITE_BUFFER_FLUSH(ah);
 }


 static void ath9k_hw_nf_sanitize(struct ath_hw *ah, s16 *nf)
 {
 	struct ath_common *common = ath9k_hw_common(ah);
 	struct ath_nf_limits *limit;
 	int i;

 	if (IS_CHAN_2GHZ(ah->curchan))
 		limit = &ah->nf_2g;
 	else
 		limit = &ah->nf_5g;

 	for (i = 0; i < NUM_NF_READINGS; i++) {
 		if (!nf[i])
 			continue;

 		ath_dbg(common, ATH_DBG_CALIBRATE,
 			"NF calibrated [%s] [chain %d] is %d\n",
 			(i >= 3 ? "ext" : "ctl"), i % 3, nf[i]);

 		if (nf[i] > ATH9K_NF_TOO_HIGH) {
 			ath_dbg(common, ATH_DBG_CALIBRATE,
 				"NF[%d] (%d) > MAX (%d), correcting to MAX\n",
 				i, nf[i], ATH9K_NF_TOO_HIGH);
 			nf[i] = limit->max;
 		} else if (nf[i] < limit->min) {
 			ath_dbg(common, ATH_DBG_CALIBRATE,
 				"NF[%d] (%d) < MIN (%d), correcting to NOM\n",
 				i, nf[i], limit->min);
 			nf[i] = limit->nominal;
 		}
 	}
 }

 bool ath9k_hw_getnf(struct ath_hw *ah, struct ath9k_channel *chan)
 {
 	struct ath_common *common = ath9k_hw_common(ah);
 	int16_t nf, nfThresh;
 	int16_t nfarray[NUM_NF_READINGS] = { 0 };
 	struct ath9k_nfcal_hist *h;
 	struct ieee80211_channel *c = chan->chan;
 	struct ath9k_hw_cal_data *caldata = ah->caldata;

 	chan->channelFlags &= (~CHANNEL_CW_INT);
 	if (REG_READ(ah, AR_PHY_AGC_CONTROL) & AR_PHY_AGC_CONTROL_NF) {
 		ath_dbg(common, ATH_DBG_CALIBRATE,
 			"NF did not complete in calibration window\n");
 		return false;
 	}

 	ath9k_hw_do_getnf(ah, nfarray);
 	ath9k_hw_nf_sanitize(ah, nfarray);
 	nf = nfarray[0];
 	if (ath9k_hw_get_nf_thresh(ah, c->band, &nfThresh)
 	    && nf > nfThresh) {
 		ath_dbg(common, ATH_DBG_CALIBRATE,
 			"noise floor failed detected; detected %d, threshold %d\n",
 			nf, nfThresh);
 		chan->channelFlags |= CHANNEL_CW_INT;
 	}

 	if (!caldata) {
 		chan->noisefloor = nf;
 		return false;
 	}

 	h = caldata->nfCalHist;
 	caldata->nfcal_pending = false;
 	ath9k_hw_update_nfcal_hist_buffer(ah, caldata, nfarray);
 	chan->noisefloor = h[0].privNF;
 	return true;
 }

 void ath9k_init_nfcal_hist_buffer(struct ath_hw *ah,
 				  struct ath9k_channel *chan)
 {
 	struct ath9k_nfcal_hist *h;
 	s16 default_nf;
 	int i, j;

 	ah->caldata->channel = chan->channel;
 	ah->caldata->channelFlags = chan->channelFlags & ~CHANNEL_CW_INT;
 	h = ah->caldata->nfCalHist;
 	default_nf = ath9k_hw_get_default_nf(ah, chan);
 	for (i = 0; i < NUM_NF_READINGS; i++) {
 		h[i].currIndex = 0;
 		h[i].privNF = default_nf;
 		h[i].invalidNFcount = AR_PHY_CCA_FILTERWINDOW_LENGTH;
 		for (j = 0; j < ATH9K_NF_CAL_HIST_MAX; j++) {
 			h[i].nfCalBuffer[j] = default_nf;
 		}
 	}
 }


 void ath9k_hw_bstuck_nfcal(struct ath_hw *ah)
 {
 	struct ath9k_hw_cal_data *caldata = ah->caldata;

 	if (unlikely(!caldata))
 		return;

 	/*
 	 * If beacons are stuck, the most likely cause is interference.
 	 * Triggering a noise floor calibration at this point helps the
 	 * hardware adapt to a noisy environment much faster.
 	 * To ensure that we recover from stuck beacons quickly, let
 	 * the baseband update the internal NF value itself, similar to
 	 * what is being done after a full reset.
 	 */
 	if (!caldata->nfcal_pending)
 		ath9k_hw_start_nfcal(ah, true);
 	else if (!(REG_READ(ah, AR_PHY_AGC_CONTROL) & AR_PHY_AGC_CONTROL_NF))
 		ath9k_hw_getnf(ah, ah->curchan);

 	caldata->nfcal_interference = true;
 }
 EXPORT_SYMBOL(ath9k_hw_bstuck_nfcal);
	/*
	* Copyright (c) 2008-2011 Atheros Communications 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 "hw.h"
	#include "hw-ops.h"

	/* Common calibration code */

	#define ATH9K_NF_TOO_HIGH -60

	static int16_t ath9k_hw_get_nf_hist_mid(int16_t *nfCalBuffer)
	{
	int16_t nfval;
	int16_t sort[ATH9K_NF_CAL_HIST_MAX];
	int i, j;

	for (i = 0; i < ATH9K_NF_CAL_HIST_MAX; i++)
	sort[i] = nfCalBuffer[i];

	for (i = 0; i < ATH9K_NF_CAL_HIST_MAX - 1; i++) {
	for (j = 1; j < ATH9K_NF_CAL_HIST_MAX - i; j++) {
	if (sort[j] > sort[j - 1]) {
	nfval = sort[j];
	sort[j] = sort[j - 1];
	sort[j - 1] = nfval;
	}
	}
	}
	nfval = sort[(ATH9K_NF_CAL_HIST_MAX - 1) >> 1];

	return nfval;
	}

	static struct ath_nf_limits ath9k_hw_get_nf_limits(struct ath_hw ah,
	struct ath9k_channel *chan)
	{
	struct ath_nf_limits *limit;

	if (!chan \|\| IS_CHAN_2GHZ(chan))
	limit = &ah->nf_2g;
	else
	limit = &ah->nf_5g;

	return limit;
	}

	static s16 ath9k_hw_get_default_nf(struct ath_hw *ah,
	struct ath9k_channel *chan)
	{
	return ath9k_hw_get_nf_limits(ah, chan)->nominal;
	}


	static void ath9k_hw_update_nfcal_hist_buffer(struct ath_hw *ah,
	struct ath9k_hw_cal_data *cal,
	int16_t *nfarray)
	{
	struct ath_common *common = ath9k_hw_common(ah);
	struct ieee80211_conf *conf = &common->hw->conf;
	struct ath_nf_limits *limit;
	struct ath9k_nfcal_hist *h;
	bool high_nf_mid = false;
	u8 chainmask = (ah->rxchainmask << 3) \| ah->rxchainmask;
	int i;

	h = cal->nfCalHist;
	limit = ath9k_hw_get_nf_limits(ah, ah->curchan);

	for (i = 0; i < NUM_NF_READINGS; i++) {
	if (!(chainmask & (1 << i)) \|\|
	((i >= AR5416_MAX_CHAINS) && !conf_is_ht40(conf)))
	continue;

	h[i].nfCalBuffer[h[i].currIndex] = nfarray[i];

	if (++h[i].currIndex >= ATH9K_NF_CAL_HIST_MAX)
	h[i].currIndex = 0;

	if (h[i].invalidNFcount > 0) {
	h[i].invalidNFcount--;
	h[i].privNF = nfarray[i];
	} else {
	h[i].privNF =
	ath9k_hw_get_nf_hist_mid(h[i].nfCalBuffer);
	}

	if (!h[i].privNF)
	continue;

	if (h[i].privNF > limit->max) {
	high_nf_mid = true;

	ath_dbg(common, ATH_DBG_CALIBRATE,
	"NFmid[%d] (%d) > MAX (%d), %s\n",
	i, h[i].privNF, limit->max,
	(cal->nfcal_interference ?
	"not corrected (due to interference)" :
	"correcting to MAX"));

	/*
	* Normally we limit the average noise floor by the
	* hardware specific maximum here. However if we have
	* encountered stuck beacons because of interference,
	* we bypass this limit here in order to better deal
	* with our environment.
	*/
	if (!cal->nfcal_interference)
	h[i].privNF = limit->max;
	}
	}

	/*
	* If the noise floor seems normal for all chains, assume that
	* there is no significant interference in the environment anymore.
	* Re-enable the enforcement of the NF maximum again.
	*/
	if (!high_nf_mid)
	cal->nfcal_interference = false;
	}

	static bool ath9k_hw_get_nf_thresh(struct ath_hw *ah,
	enum ieee80211_band band,
	int16_t *nft)
	{
	switch (band) {
	case IEEE80211_BAND_5GHZ:
	*nft = (int8_t)ah->eep_ops->get_eeprom(ah, EEP_NFTHRESH_5);
	break;
	case IEEE80211_BAND_2GHZ:
	*nft = (int8_t)ah->eep_ops->get_eeprom(ah, EEP_NFTHRESH_2);
	break;
	default:
	BUG_ON(1);
	return false;
	}

	return true;
	}

	void ath9k_hw_reset_calibration(struct ath_hw *ah,
	struct ath9k_cal_list *currCal)
	{
	int i;

	ath9k_hw_setup_calibration(ah, currCal);

	currCal->calState = CAL_RUNNING;

	for (i = 0; i < AR5416_MAX_CHAINS; i++) {
	ah->meas0.sign[i] = 0;
	ah->meas1.sign[i] = 0;
	ah->meas2.sign[i] = 0;
	ah->meas3.sign[i] = 0;
	}

	ah->cal_samples = 0;
	}

	/* This is done for the currently configured channel */
	bool ath9k_hw_reset_calvalid(struct ath_hw *ah)
	{
	struct ath_common *common = ath9k_hw_common(ah);
	struct ieee80211_conf *conf = &common->hw->conf;
	struct ath9k_cal_list *currCal = ah->cal_list_curr;

	if (!ah->caldata)
	return true;

	if (!AR_SREV_9100(ah) && !AR_SREV_9160_10_OR_LATER(ah))
	return true;

	if (currCal == NULL)
	return true;

	if (currCal->calState != CAL_DONE) {
	ath_dbg(common, ATH_DBG_CALIBRATE,
	"Calibration state incorrect, %d\n",
	currCal->calState);
	return true;
	}

	if (!(ah->supp_cals & currCal->calData->calType))
	return true;

	ath_dbg(common, ATH_DBG_CALIBRATE,
	"Resetting Cal %d state for channel %u\n",
	currCal->calData->calType, conf->channel->center_freq);

	ah->caldata->CalValid &= ~currCal->calData->calType;
	currCal->calState = CAL_WAITING;

	return false;
	}
	EXPORT_SYMBOL(ath9k_hw_reset_calvalid);

	void ath9k_hw_start_nfcal(struct ath_hw *ah, bool update)
	{
	if (ah->caldata)
	ah->caldata->nfcal_pending = true;

	REG_SET_BIT(ah, AR_PHY_AGC_CONTROL,
	AR_PHY_AGC_CONTROL_ENABLE_NF);

	if (update)
	REG_CLR_BIT(ah, AR_PHY_AGC_CONTROL,
	AR_PHY_AGC_CONTROL_NO_UPDATE_NF);
	else
	REG_SET_BIT(ah, AR_PHY_AGC_CONTROL,
	AR_PHY_AGC_CONTROL_NO_UPDATE_NF);

	REG_SET_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_NF);
	}

	void ath9k_hw_loadnf(struct ath_hw ah, struct ath9k_channel chan)
	{
	struct ath9k_nfcal_hist *h = NULL;
	unsigned i, j;
	int32_t val;
	u8 chainmask = (ah->rxchainmask << 3) \| ah->rxchainmask;
	struct ath_common *common = ath9k_hw_common(ah);
	struct ieee80211_conf *conf = &common->hw->conf;
	s16 default_nf = ath9k_hw_get_default_nf(ah, chan);

	if (ah->caldata)
	h = ah->caldata->nfCalHist;

	for (i = 0; i < NUM_NF_READINGS; i++) {
	if (chainmask & (1 << i)) {
	s16 nfval;

	if ((i >= AR5416_MAX_CHAINS) && !conf_is_ht40(conf))
	continue;

	if (h)
	nfval = h[i].privNF;
	else
	nfval = default_nf;

	val = REG_READ(ah, ah->nf_regs[i]);
	val &= 0xFFFFFE00;
	val \|= (((u32) nfval << 1) & 0x1ff);
	REG_WRITE(ah, ah->nf_regs[i], val);
	}
	}

	/*
	* Load software filtered NF value into baseband internal minCCApwr
	* variable.
	*/
	REG_CLR_BIT(ah, AR_PHY_AGC_CONTROL,
	AR_PHY_AGC_CONTROL_ENABLE_NF);
	REG_CLR_BIT(ah, AR_PHY_AGC_CONTROL,
	AR_PHY_AGC_CONTROL_NO_UPDATE_NF);
	REG_SET_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_NF);

	/*
	* Wait for load to complete, should be fast, a few 10s of us.
	* The max delay was changed from an original 250us to 10000us
	* since 250us often results in NF load timeout and causes deaf
	* condition during stress testing 12/12/2009
	*/
	for (j = 0; j < 10000; j++) {
	if ((REG_READ(ah, AR_PHY_AGC_CONTROL) &
	AR_PHY_AGC_CONTROL_NF) == 0)
	break;
	udelay(10);
	}

	/*
	* We timed out waiting for the noisefloor to load, probably due to an
	* in-progress rx. Simply return here and allow the load plenty of time
	* to complete before the next calibration interval. We need to avoid
	* trying to load -50 (which happens below) while the previous load is
	* still in progress as this can cause rx deafness. Instead by returning
	* here, the baseband nf cal will just be capped by our present
	* noisefloor until the next calibration timer.
	*/
	if (j == 10000) {
	ath_dbg(common, ATH_DBG_ANY,
	"Timeout while waiting for nf to load: AR_PHY_AGC_CONTROL=0x%x\n",
	REG_READ(ah, AR_PHY_AGC_CONTROL));
	return;
	}

	/*
	* Restore maxCCAPower register parameter again so that we're not capped
	* by the median we just loaded. This will be initial (and max) value
	* of next noise floor calibration the baseband does.
	*/
	ENABLE_REGWRITE_BUFFER(ah);
	for (i = 0; i < NUM_NF_READINGS; i++) {
	if (chainmask & (1 << i)) {
	if ((i >= AR5416_MAX_CHAINS) && !conf_is_ht40(conf))
	continue;

	val = REG_READ(ah, ah->nf_regs[i]);
	val &= 0xFFFFFE00;
	val \|= (((u32) (-50) << 1) & 0x1ff);
	REG_WRITE(ah, ah->nf_regs[i], val);
	}
	}
	REGWRITE_BUFFER_FLUSH(ah);
	}


	static void ath9k_hw_nf_sanitize(struct ath_hw ah, s16 nf)
	{
	struct ath_common *common = ath9k_hw_common(ah);
	struct ath_nf_limits *limit;
	int i;

	if (IS_CHAN_2GHZ(ah->curchan))
	limit = &ah->nf_2g;
	else
	limit = &ah->nf_5g;

	for (i = 0; i < NUM_NF_READINGS; i++) {
	if (!nf[i])
	continue;

	ath_dbg(common, ATH_DBG_CALIBRATE,
	"NF calibrated [%s] [chain %d] is %d\n",
	(i >= 3 ? "ext" : "ctl"), i % 3, nf[i]);

	if (nf[i] > ATH9K_NF_TOO_HIGH) {
	ath_dbg(common, ATH_DBG_CALIBRATE,
	"NF[%d] (%d) > MAX (%d), correcting to MAX\n",
	i, nf[i], ATH9K_NF_TOO_HIGH);
	nf[i] = limit->max;
	} else if (nf[i] < limit->min) {
	ath_dbg(common, ATH_DBG_CALIBRATE,
	"NF[%d] (%d) < MIN (%d), correcting to NOM\n",
	i, nf[i], limit->min);
	nf[i] = limit->nominal;
	}
	}
	}

	bool ath9k_hw_getnf(struct ath_hw ah, struct ath9k_channel chan)
	{
	struct ath_common *common = ath9k_hw_common(ah);
	int16_t nf, nfThresh;
	int16_t nfarray[NUM_NF_READINGS] = { 0 };
	struct ath9k_nfcal_hist *h;
	struct ieee80211_channel *c = chan->chan;
	struct ath9k_hw_cal_data *caldata = ah->caldata;

	chan->channelFlags &= (~CHANNEL_CW_INT);
	if (REG_READ(ah, AR_PHY_AGC_CONTROL) & AR_PHY_AGC_CONTROL_NF) {
	ath_dbg(common, ATH_DBG_CALIBRATE,
	"NF did not complete in calibration window\n");
	return false;
	}

	ath9k_hw_do_getnf(ah, nfarray);
	ath9k_hw_nf_sanitize(ah, nfarray);
	nf = nfarray[0];
	if (ath9k_hw_get_nf_thresh(ah, c->band, &nfThresh)
	&& nf > nfThresh) {
	ath_dbg(common, ATH_DBG_CALIBRATE,
	"noise floor failed detected; detected %d, threshold %d\n",
	nf, nfThresh);
	chan->channelFlags \|= CHANNEL_CW_INT;
	}

	if (!caldata) {
	chan->noisefloor = nf;
	return false;
	}

	h = caldata->nfCalHist;
	caldata->nfcal_pending = false;
	ath9k_hw_update_nfcal_hist_buffer(ah, caldata, nfarray);
	chan->noisefloor = h[0].privNF;
	return true;
	}

	void ath9k_init_nfcal_hist_buffer(struct ath_hw *ah,
	struct ath9k_channel *chan)
	{
	struct ath9k_nfcal_hist *h;
	s16 default_nf;
	int i, j;

	ah->caldata->channel = chan->channel;
	ah->caldata->channelFlags = chan->channelFlags & ~CHANNEL_CW_INT;
	h = ah->caldata->nfCalHist;
	default_nf = ath9k_hw_get_default_nf(ah, chan);
	for (i = 0; i < NUM_NF_READINGS; i++) {
	h[i].currIndex = 0;
	h[i].privNF = default_nf;
	h[i].invalidNFcount = AR_PHY_CCA_FILTERWINDOW_LENGTH;
	for (j = 0; j < ATH9K_NF_CAL_HIST_MAX; j++) {
	h[i].nfCalBuffer[j] = default_nf;
	}
	}
	}


	void ath9k_hw_bstuck_nfcal(struct ath_hw *ah)
	{
	struct ath9k_hw_cal_data *caldata = ah->caldata;

	if (unlikely(!caldata))
	return;

	/*
	* If beacons are stuck, the most likely cause is interference.
	* Triggering a noise floor calibration at this point helps the
	* hardware adapt to a noisy environment much faster.
	* To ensure that we recover from stuck beacons quickly, let
	* the baseband update the internal NF value itself, similar to
	* what is being done after a full reset.
	*/
	if (!caldata->nfcal_pending)
	ath9k_hw_start_nfcal(ah, true);
	else if (!(REG_READ(ah, AR_PHY_AGC_CONTROL) & AR_PHY_AGC_CONTROL_NF))
	ath9k_hw_getnf(ah, ah->curchan);

	caldata->nfcal_interference = true;
	}
	EXPORT_SYMBOL(ath9k_hw_bstuck_nfcal);