ar5416_cal.c

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/*-
 * SPDX-License-Identifier: ISC
 *
 * Copyright (c) 2002-2009 Sam Leffler, Errno Consulting
 * Copyright (c) 2002-2008 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.
 *
 * $FreeBSD$
 */
#include "opt_ah.h"
 
#include "ah.h"
#include "ah_internal.h"
#include "ah_devid.h"
 
#include "ah_eeprom_v14.h"
 
#include "ar5212/ar5212.h"      /* for NF cal related declarations */
 
#include "ar5416/ar5416.h"
#include "ar5416/ar5416reg.h"
#include "ar5416/ar5416phy.h"
 
/* Owl specific stuff */
#define NUM_NOISEFLOOR_READINGS 6       /* 3 chains * (ctl + ext) */
 
static void ar5416StartNFCal(struct ath_hal *ah);
static HAL_BOOL ar5416LoadNF(struct ath_hal *ah, const struct ieee80211_channel *);
static int16_t ar5416GetNf(struct ath_hal *, struct ieee80211_channel *);
 
static uint16_t ar5416GetDefaultNF(struct ath_hal *ah, const struct ieee80211_channel *chan);
static void ar5416SanitizeNF(struct ath_hal *ah, int16_t *nf);
 
/*
 * Determine if calibration is supported by device and channel flags
 */
 
/*
 * ADC GAIN/DC offset calibration is for calibrating two ADCs that
 * are acting as one by interleaving incoming symbols. This isn't
 * relevant for 2.4GHz 20MHz wide modes because, as far as I can tell,
 * the secondary ADC is never enabled. It is enabled however for
 * 5GHz modes.
 *
 * It hasn't been confirmed whether doing this calibration is needed
 * at all in the above modes and/or whether it's actually harmful.
 * So for now, let's leave it enabled and just remember to get
 * confirmation that it needs to be clarified.
 *
 * See US Patent No: US 7,541,952 B1:
 *  " Method and Apparatus for Offset and Gain Compensation for
 *    Analog-to-Digital Converters."
 */
static OS_INLINE HAL_BOOL
ar5416IsCalSupp(struct ath_hal *ah, const struct ieee80211_channel *chan,
        HAL_CAL_TYPE calType) 
{
        struct ar5416PerCal *cal = &AH5416(ah)->ah_cal;
 
        switch (calType & cal->suppCals) {
        case IQ_MISMATCH_CAL:
                /* Run IQ Mismatch for non-CCK only */
                return !IEEE80211_IS_CHAN_B(chan);
        case ADC_GAIN_CAL:
        case ADC_DC_CAL:
                /*
                 * Run ADC Gain Cal for either 5ghz any or 2ghz HT40.
                 *
                 * Don't run ADC calibrations for 5ghz fast clock mode
                 * in HT20 - only one ADC is used.
                 */
                if (IEEE80211_IS_CHAN_HT20(chan) &&
                    (IS_5GHZ_FAST_CLOCK_EN(ah, chan)))
                        return AH_FALSE;
                if (IEEE80211_IS_CHAN_5GHZ(chan))
                        return AH_TRUE;
                if (IEEE80211_IS_CHAN_HT40(chan))
                        return AH_TRUE;
                return AH_FALSE;
        }
        return AH_FALSE;
}
 
/*
 * Setup HW to collect samples used for current cal
 */
static void
ar5416SetupMeasurement(struct ath_hal *ah, HAL_CAL_LIST *currCal)
{
        /* Start calibration w/ 2^(INIT_IQCAL_LOG_COUNT_MAX+1) samples */
        OS_REG_RMW_FIELD(ah, AR_PHY_TIMING_CTRL4,
            AR_PHY_TIMING_CTRL4_IQCAL_LOG_COUNT_MAX,
            currCal->calData->calCountMax);
 
        /* Select calibration to run */
        switch (currCal->calData->calType) {
        case IQ_MISMATCH_CAL:
                OS_REG_WRITE(ah, AR_PHY_CALMODE, AR_PHY_CALMODE_IQ);
                HALDEBUG(ah, HAL_DEBUG_PERCAL,
                    "%s: start IQ Mismatch calibration\n", __func__);
                break;
        case ADC_GAIN_CAL:
                OS_REG_WRITE(ah, AR_PHY_CALMODE, AR_PHY_CALMODE_ADC_GAIN);
                HALDEBUG(ah, HAL_DEBUG_PERCAL,
                    "%s: start ADC Gain calibration\n", __func__);
                break;
        case ADC_DC_CAL:
                OS_REG_WRITE(ah, AR_PHY_CALMODE, AR_PHY_CALMODE_ADC_DC_PER);
                HALDEBUG(ah, HAL_DEBUG_PERCAL,
                    "%s: start ADC DC calibration\n", __func__);
                break;
        case ADC_DC_INIT_CAL:
                OS_REG_WRITE(ah, AR_PHY_CALMODE, AR_PHY_CALMODE_ADC_DC_INIT);
                HALDEBUG(ah, HAL_DEBUG_PERCAL,
                    "%s: start Init ADC DC calibration\n", __func__);
                break;
        }
        /* Kick-off cal */
        OS_REG_SET_BIT(ah, AR_PHY_TIMING_CTRL4, AR_PHY_TIMING_CTRL4_DO_CAL);
}
 
/*
 * Initialize shared data structures and prepare a cal to be run.
 */
static void
ar5416ResetMeasurement(struct ath_hal *ah, HAL_CAL_LIST *currCal)
{
        struct ar5416PerCal *cal = &AH5416(ah)->ah_cal;
 
        /* Reset data structures shared between different calibrations */
        OS_MEMZERO(cal->caldata, sizeof(cal->caldata));
        cal->calSamples = 0;
 
        /* Setup HW for new calibration */
        ar5416SetupMeasurement(ah, currCal);
 
        /* Change SW state to RUNNING for this calibration */
        currCal->calState = CAL_RUNNING;
}
 
#if 0
/*
 * Run non-periodic calibrations.
 */
static HAL_BOOL
ar5416RunInitCals(struct ath_hal *ah, int init_cal_count)
{
        struct ath_hal_5416 *ahp = AH5416(ah);
        struct ar5416PerCal *cal = &AH5416(ah)->ah_cal;
        HAL_CHANNEL_INTERNAL ichan;     /* XXX bogus */
        HAL_CAL_LIST *curCal = ahp->ah_cal_curr;
        HAL_BOOL isCalDone;
        int i;
 
        if (curCal == AH_NULL)
                return AH_FALSE;
 
        ichan.calValid = 0;
        for (i = 0; i < init_cal_count; i++) {
                /* Reset this Cal */
                ar5416ResetMeasurement(ah, curCal);
                /* Poll for offset calibration complete */
                if (!ath_hal_wait(ah, AR_PHY_TIMING_CTRL4, AR_PHY_TIMING_CTRL4_DO_CAL, 0)) {
                        HALDEBUG(ah, HAL_DEBUG_ANY,
                            "%s: Cal %d failed to finish in 100ms.\n",
                            __func__, curCal->calData->calType);
                        /* Re-initialize list pointers for periodic cals */
                        cal->cal_list = cal->cal_last = cal->cal_curr = AH_NULL;
                        return AH_FALSE;
                }
                /* Run this cal */
                ar5416DoCalibration(ah, &ichan, ahp->ah_rxchainmask,
                    curCal, &isCalDone);
                if (!isCalDone)
                        HALDEBUG(ah, HAL_DEBUG_ANY,
                            "%s: init cal %d did not complete.\n",
                            __func__, curCal->calData->calType);
                if (curCal->calNext != AH_NULL)
                        curCal = curCal->calNext;
        }
 
        /* Re-initialize list pointers for periodic cals */
        cal->cal_list = cal->cal_last = cal->cal_curr = AH_NULL;
        return AH_TRUE;
}
#endif
 
/*
 * AGC calibration for the AR5416, AR9130, AR9160, AR9280.
 */
HAL_BOOL
ar5416InitCalHardware(struct ath_hal *ah, const struct ieee80211_channel *chan)
{
 
        if (AR_SREV_MERLIN_10_OR_LATER(ah)) {
                /* Disable ADC */
                OS_REG_CLR_BIT(ah, AR_PHY_ADC_CTL,
                    AR_PHY_ADC_CTL_OFF_PWDADC);
 
                /* Enable Rx Filter Cal */
                OS_REG_SET_BIT(ah, AR_PHY_AGC_CONTROL,
                    AR_PHY_AGC_CONTROL_FLTR_CAL);
        }       
 
        /* Calibrate the AGC */
        OS_REG_SET_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_CAL);
 
        /* Poll for offset calibration complete */
        if (!ath_hal_wait(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_CAL, 0)) {
                HALDEBUG(ah, HAL_DEBUG_ANY,
                    "%s: offset calibration did not complete in 1ms; "
                    "noisy environment?\n", __func__);
                return AH_FALSE;
        }
 
        if (AR_SREV_MERLIN_10_OR_LATER(ah)) {
                /* Enable ADC */
                OS_REG_SET_BIT(ah, AR_PHY_ADC_CTL,
                    AR_PHY_ADC_CTL_OFF_PWDADC);
 
                /* Disable Rx Filter Cal */
                OS_REG_CLR_BIT(ah, AR_PHY_AGC_CONTROL,
                    AR_PHY_AGC_CONTROL_FLTR_CAL);
        }
 
        return AH_TRUE;
}
 
/*
 * Initialize Calibration infrastructure.
 */
#define MAX_CAL_CHECK           32
HAL_BOOL
ar5416InitCal(struct ath_hal *ah, const struct ieee80211_channel *chan)
{
        struct ar5416PerCal *cal = &AH5416(ah)->ah_cal;
        HAL_CHANNEL_INTERNAL *ichan;
 
        ichan = ath_hal_checkchannel(ah, chan);
        HALASSERT(ichan != AH_NULL);
 
        /* Do initial chipset-specific calibration */
        if (! AH5416(ah)->ah_cal_initcal(ah, chan)) {
                HALDEBUG(ah, HAL_DEBUG_ANY,
                    "%s: initial chipset calibration did "
                    "not complete in time; noisy environment?\n", __func__);
                return AH_FALSE;
        }
 
        /* If there's PA Cal, do it */
        if (AH5416(ah)->ah_cal_pacal)
                AH5416(ah)->ah_cal_pacal(ah, AH_TRUE);
 
        /* 
         * Do NF calibration after DC offset and other CALs.
         * Per system engineers, noise floor value can sometimes be 20 dB
         * higher than normal value if DC offset and noise floor cal are
         * triggered at the same time.
         */
        OS_REG_SET_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_NF);
 
        /*
         * This may take a while to run; make sure subsequent
         * calibration routines check that this has completed
         * before reading the value and triggering a subsequent
         * calibration.
         */
 
        /* Initialize list pointers */
        cal->cal_list = cal->cal_last = cal->cal_curr = AH_NULL;
 
        /*
         * Enable IQ, ADC Gain, ADC DC Offset Cals
         */
        if (AR_SREV_HOWL(ah) || AR_SREV_SOWL_10_OR_LATER(ah)) {
                /* Setup all non-periodic, init time only calibrations */
                /* XXX: Init DC Offset not working yet */
#if 0
                if (ar5416IsCalSupp(ah, chan, ADC_DC_INIT_CAL)) {
                        INIT_CAL(&cal->adcDcCalInitData);
                        INSERT_CAL(cal, &cal->adcDcCalInitData);
                }
                /* Initialize current pointer to first element in list */
                cal->cal_curr = cal->cal_list;
 
                if (cal->ah_cal_curr != AH_NULL && !ar5416RunInitCals(ah, 0))
                        return AH_FALSE;
#endif
        }
 
        /* If Cals are supported, add them to list via INIT/INSERT_CAL */
        if (ar5416IsCalSupp(ah, chan, ADC_GAIN_CAL)) {
                INIT_CAL(&cal->adcGainCalData);
                INSERT_CAL(cal, &cal->adcGainCalData);
                HALDEBUG(ah, HAL_DEBUG_PERCAL,
                    "%s: enable ADC Gain Calibration.\n", __func__);
        }
        if (ar5416IsCalSupp(ah, chan, ADC_DC_CAL)) {
                INIT_CAL(&cal->adcDcCalData);
                INSERT_CAL(cal, &cal->adcDcCalData);
                HALDEBUG(ah, HAL_DEBUG_PERCAL,
                    "%s: enable ADC DC Calibration.\n", __func__);
        }
        if (ar5416IsCalSupp(ah, chan, IQ_MISMATCH_CAL)) {
                INIT_CAL(&cal->iqCalData);
                INSERT_CAL(cal, &cal->iqCalData);
                HALDEBUG(ah, HAL_DEBUG_PERCAL,
                    "%s: enable IQ Calibration.\n", __func__);
        }
        /* Initialize current pointer to first element in list */
        cal->cal_curr = cal->cal_list;
 
        /* Kick off measurements for the first cal */
        if (cal->cal_curr != AH_NULL)
                ar5416ResetMeasurement(ah, cal->cal_curr);
 
        /* Mark all calibrations on this channel as being invalid */
        ichan->calValid = 0;
 
        return AH_TRUE;
#undef  MAX_CAL_CHECK
}
 
/*
 * Entry point for upper layers to restart current cal.
 * Reset the calibration valid bit in channel.
 */
HAL_BOOL
ar5416ResetCalValid(struct ath_hal *ah, const struct ieee80211_channel *chan)
{
        struct ar5416PerCal *cal = &AH5416(ah)->ah_cal;
        HAL_CHANNEL_INTERNAL *ichan = ath_hal_checkchannel(ah, chan);
        HAL_CAL_LIST *currCal = cal->cal_curr;
 
        if (!AR_SREV_SOWL_10_OR_LATER(ah))
                return AH_FALSE;
        if (currCal == AH_NULL)
                return AH_FALSE;
        if (ichan == AH_NULL) {
                HALDEBUG(ah, HAL_DEBUG_ANY,
                    "%s: invalid channel %u/0x%x; no mapping\n",
                    __func__, chan->ic_freq, chan->ic_flags);
                return AH_FALSE;
        }
        /*
         * Expected that this calibration has run before, post-reset.
         * Current state should be done
         */
        if (currCal->calState != CAL_DONE) {
                HALDEBUG(ah, HAL_DEBUG_ANY,
                    "%s: Calibration state incorrect, %d\n",
                    __func__, currCal->calState);
                return AH_FALSE;
        }
 
        /* Verify Cal is supported on this channel */
        if (!ar5416IsCalSupp(ah, chan, currCal->calData->calType))
                return AH_FALSE;
 
        HALDEBUG(ah, HAL_DEBUG_PERCAL,
            "%s: Resetting Cal %d state for channel %u/0x%x\n",
            __func__, currCal->calData->calType, chan->ic_freq,
            chan->ic_flags);
 
        /* Disable cal validity in channel */
        ichan->calValid &= ~currCal->calData->calType;
        currCal->calState = CAL_WAITING;
 
        return AH_TRUE;
}
 
/*
 * Recalibrate the lower PHY chips to account for temperature/environment
 * changes.
 */
static void
ar5416DoCalibration(struct ath_hal *ah,  HAL_CHANNEL_INTERNAL *ichan,
        uint8_t rxchainmask, HAL_CAL_LIST *currCal, HAL_BOOL *isCalDone)
{
        struct ar5416PerCal *cal = &AH5416(ah)->ah_cal;
 
        /* Cal is assumed not done until explicitly set below */
        *isCalDone = AH_FALSE;
 
        HALDEBUG(ah, HAL_DEBUG_PERCAL,
            "%s: %s Calibration, state %d, calValid 0x%x\n",
            __func__, currCal->calData->calName, currCal->calState,
            ichan->calValid);
 
        /* Calibration in progress. */
        if (currCal->calState == CAL_RUNNING) {
                /* Check to see if it has finished. */
                if (!(OS_REG_READ(ah, AR_PHY_TIMING_CTRL4) & AR_PHY_TIMING_CTRL4_DO_CAL)) {
                        HALDEBUG(ah, HAL_DEBUG_PERCAL,
                            "%s: sample %d of %d finished\n",
                            __func__, cal->calSamples,
                            currCal->calData->calNumSamples);
                        /* 
                         * Collect measurements for active chains.
                         */
                        currCal->calData->calCollect(ah);
                        if (++cal->calSamples >= currCal->calData->calNumSamples) {
                                int i, numChains = 0;
                                for (i = 0; i < AR5416_MAX_CHAINS; i++) {
                                        if (rxchainmask & (1 << i))
                                                numChains++;
                                }
                                /* 
                                 * Process accumulated data
                                 */
                                currCal->calData->calPostProc(ah, numChains);
 
                                /* Calibration has finished. */
                                ichan->calValid |= currCal->calData->calType;
                                currCal->calState = CAL_DONE;
                                *isCalDone = AH_TRUE;
                        } else {
                                /*
                                 * Set-up to collect of another sub-sample.
                                 */
                                ar5416SetupMeasurement(ah, currCal);
                        }
                }
        } else if (!(ichan->calValid & currCal->calData->calType)) {
                /* If current cal is marked invalid in channel, kick it off */
                ar5416ResetMeasurement(ah, currCal);
        }
}
 
/*
 * Internal interface to schedule periodic calibration work.
 */
HAL_BOOL
ar5416PerCalibrationN(struct ath_hal *ah, struct ieee80211_channel *chan,
        u_int rxchainmask, HAL_BOOL longcal, HAL_BOOL *isCalDone)
{
        struct ar5416PerCal *cal = &AH5416(ah)->ah_cal;
        HAL_CAL_LIST *currCal = cal->cal_curr;
        HAL_CHANNEL_INTERNAL *ichan;
        int r;
 
        OS_MARK(ah, AH_MARK_PERCAL, chan->ic_freq);
 
        *isCalDone = AH_TRUE;
 
        /*
         * Since ath_hal calls the PerCal method with rxchainmask=0x1;
         * override it with the current chainmask. The upper levels currently
         * doesn't know about the chainmask.
         */
        rxchainmask = AH5416(ah)->ah_rx_chainmask;
 
        /* Invalid channel check */
        ichan = ath_hal_checkchannel(ah, chan);
        if (ichan == AH_NULL) {
                HALDEBUG(ah, HAL_DEBUG_ANY,
                    "%s: invalid channel %u/0x%x; no mapping\n",
                    __func__, chan->ic_freq, chan->ic_flags);
                return AH_FALSE;
        }
 
        /*
         * For given calibration:
         * 1. Call generic cal routine
         * 2. When this cal is done (isCalDone) if we have more cals waiting
         *    (eg after reset), mask this to upper layers by not propagating
         *    isCalDone if it is set to TRUE.
         *    Instead, change isCalDone to FALSE and setup the waiting cal(s)
         *    to be run.
         */
        if (currCal != AH_NULL &&
            (currCal->calState == CAL_RUNNING ||
             currCal->calState == CAL_WAITING)) {
                ar5416DoCalibration(ah, ichan, rxchainmask, currCal, isCalDone);
                if (*isCalDone == AH_TRUE) {
                        cal->cal_curr = currCal = currCal->calNext;
                        if (currCal->calState == CAL_WAITING) {
                                *isCalDone = AH_FALSE;
                                ar5416ResetMeasurement(ah, currCal);
                        }
                }
        }
 
        /* Do NF cal only at longer intervals */
        if (longcal) {
                /* Do PA calibration if the chipset supports */
                if (AH5416(ah)->ah_cal_pacal)
                        AH5416(ah)->ah_cal_pacal(ah, AH_FALSE);
 
                /* Do open-loop temperature compensation if the chipset needs it */
                if (ath_hal_eepromGetFlag(ah, AR_EEP_OL_PWRCTRL))
                        AH5416(ah)->ah_olcTempCompensation(ah);
 
                /*
                 * Get the value from the previous NF cal
                 * and update the history buffer.
                 */
                r = ar5416GetNf(ah, chan);
                if (r == 0 || r == -1) {
                        /* NF calibration result isn't valid */
                        HALDEBUG(ah, HAL_DEBUG_UNMASKABLE, "%s: NF calibration"
                            " didn't finish; delaying CCA\n", __func__);
                } else {
                        int ret;
                        /* 
                         * NF calibration result is valid.
                         *
                         * Load the NF from history buffer of the current channel.
                         * NF is slow time-variant, so it is OK to use a
                         * historical value.
                         */
                        ret = ar5416LoadNF(ah, AH_PRIVATE(ah)->ah_curchan);
 
                        /* start NF calibration, without updating BB NF register*/
                        ar5416StartNFCal(ah);
 
                        /*
                         * If we failed calibration then tell the driver
                         * we failed and it should do a full chip reset
                         */
                        if (! ret)
                                return AH_FALSE;
                }
        }
        return AH_TRUE;
}
 
/*
 * Recalibrate the lower PHY chips to account for temperature/environment
 * changes.
 */
HAL_BOOL
ar5416PerCalibration(struct ath_hal *ah, struct ieee80211_channel *chan,
        HAL_BOOL *isIQdone)
{
        struct ath_hal_5416 *ahp = AH5416(ah);
        struct ar5416PerCal *cal = &AH5416(ah)->ah_cal;
        HAL_CAL_LIST *curCal = cal->cal_curr;
 
        if (curCal != AH_NULL && curCal->calData->calType == IQ_MISMATCH_CAL) {
                return ar5416PerCalibrationN(ah, chan, ahp->ah_rx_chainmask,
                    AH_TRUE, isIQdone);
        } else {
                HAL_BOOL isCalDone;
 
                *isIQdone = AH_FALSE;
                return ar5416PerCalibrationN(ah, chan, ahp->ah_rx_chainmask,
                    AH_TRUE, &isCalDone);
        }
}
 
static HAL_BOOL
ar5416GetEepromNoiseFloorThresh(struct ath_hal *ah,
        const struct ieee80211_channel *chan, int16_t *nft)
{
        if (IEEE80211_IS_CHAN_5GHZ(chan)) {
                ath_hal_eepromGet(ah, AR_EEP_NFTHRESH_5, nft);
                return AH_TRUE;
        }
        if (IEEE80211_IS_CHAN_2GHZ(chan)) {
                ath_hal_eepromGet(ah, AR_EEP_NFTHRESH_2, nft);
                return AH_TRUE;
        }
        HALDEBUG(ah, HAL_DEBUG_ANY, "%s: invalid channel flags 0x%x\n",
            __func__, chan->ic_flags);
        return AH_FALSE;
}
 
static void
ar5416StartNFCal(struct ath_hal *ah)
{
        OS_REG_SET_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_ENABLE_NF);
        OS_REG_SET_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_NO_UPDATE_NF);
        OS_REG_SET_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_NF);
}
 
static HAL_BOOL
ar5416LoadNF(struct ath_hal *ah, const struct ieee80211_channel *chan)
{
        static const uint32_t ar5416_cca_regs[] = {
                AR_PHY_CCA,
                AR_PHY_CH1_CCA,
                AR_PHY_CH2_CCA,
                AR_PHY_EXT_CCA,
                AR_PHY_CH1_EXT_CCA,
                AR_PHY_CH2_EXT_CCA
        };
        struct ar5212NfCalHist *h;
        int i;
        int32_t val;
        uint8_t chainmask;
        int16_t default_nf = ar5416GetDefaultNF(ah, chan);
 
        /*
         * Force NF calibration for all chains.
         */
        if (AR_SREV_KITE(ah)) {
                /* Kite has only one chain */
                chainmask = 0x9;
        } else if (AR_SREV_MERLIN(ah) || AR_SREV_KIWI(ah)) {
                /* Merlin/Kiwi has only two chains */
                chainmask = 0x1B;
        } else {
                chainmask = 0x3F;
        }
 
        /*
         * Write filtered NF values into maxCCApwr register parameter
         * so we can load below.
         */
        h = AH5416(ah)->ah_cal.nfCalHist;
        HALDEBUG(ah, HAL_DEBUG_NFCAL, "CCA: ");
        for (i = 0; i < AR5416_NUM_NF_READINGS; i ++) {
                /* Don't write to EXT radio CCA registers unless in HT/40 mode */
                /* XXX this check should really be cleaner! */
                if (i > 2 && !IEEE80211_IS_CHAN_HT40(chan))
                        continue;
 
                if (chainmask & (1 << i)) { 
                        int16_t nf_val;
 
                        if (h)
                                nf_val = h[i].privNF;
                        else
                                nf_val = default_nf;
 
                        val = OS_REG_READ(ah, ar5416_cca_regs[i]);
                        val &= 0xFFFFFE00;
                        val |= (((uint32_t) nf_val << 1) & 0x1ff);
                        HALDEBUG(ah, HAL_DEBUG_NFCAL, "[%d: %d]", i, nf_val);
                        OS_REG_WRITE(ah, ar5416_cca_regs[i], val);
                }
        }
        HALDEBUG(ah, HAL_DEBUG_NFCAL, "\n");
 
        /* Load software filtered NF value into baseband internal minCCApwr variable. */
        OS_REG_CLR_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_ENABLE_NF);
        OS_REG_CLR_BIT(ah, AR_PHY_AGC_CONTROL, AR_PHY_AGC_CONTROL_NO_UPDATE_NF);
        OS_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. */
        if (! ar5212WaitNFCalComplete(ah, 1000)) {
                /*
                 * 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.
                 */
                HALDEBUG(ah, HAL_DEBUG_UNMASKABLE, "Timeout while waiting for "
                    "nf to load: AR_PHY_AGC_CONTROL=0x%x\n",
                    OS_REG_READ(ah, AR_PHY_AGC_CONTROL));
                return AH_FALSE;
        }
 
        /*
         * 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.  
         */
        for (i = 0; i < AR5416_NUM_NF_READINGS; i ++) {
                /* Don't write to EXT radio CCA registers unless in HT/40 mode */
                /* XXX this check should really be cleaner! */
                if (i > 2 && !IEEE80211_IS_CHAN_HT40(chan))
                        continue;
 
                if (chainmask & (1 << i)) {     
                        val = OS_REG_READ(ah, ar5416_cca_regs[i]);
                        val &= 0xFFFFFE00;
                        val |= (((uint32_t)(-50) << 1) & 0x1ff);
                        OS_REG_WRITE(ah, ar5416_cca_regs[i], val);
                }
        }
        return AH_TRUE;
}
 
/*
 * This just initialises the "good" values for AR5416 which
 * may not be right; it'lll be overridden by ar5416SanitizeNF()
 * to nominal values.
 */
void
ar5416InitNfHistBuff(struct ar5212NfCalHist *h)
{
        int i, j;
 
        for (i = 0; i < AR5416_NUM_NF_READINGS; i ++) {
                h[i].currIndex = 0;
                h[i].privNF = AR5416_CCA_MAX_GOOD_VALUE;
                h[i].invalidNFcount = AR512_NF_CAL_HIST_MAX;
                for (j = 0; j < AR512_NF_CAL_HIST_MAX; j ++)
                        h[i].nfCalBuffer[j] = AR5416_CCA_MAX_GOOD_VALUE;
        }
}
 
/*
 * Update the noise floor buffer as a ring buffer
 */
static void
ar5416UpdateNFHistBuff(struct ath_hal *ah, struct ar5212NfCalHist *h,
    int16_t *nfarray)
{
        int i;
 
        /* XXX TODO: don't record nfarray[] entries for inactive chains */
        for (i = 0; i < AR5416_NUM_NF_READINGS; i ++) {
                h[i].nfCalBuffer[h[i].currIndex] = nfarray[i];
 
                if (++h[i].currIndex >= AR512_NF_CAL_HIST_MAX)
                        h[i].currIndex = 0;
                if (h[i].invalidNFcount > 0) {
                        if (nfarray[i] < AR5416_CCA_MIN_BAD_VALUE ||
                            nfarray[i] > AR5416_CCA_MAX_HIGH_VALUE) {
                                h[i].invalidNFcount = AR512_NF_CAL_HIST_MAX;
                        } else {
                                h[i].invalidNFcount--;
                                h[i].privNF = nfarray[i];
                        }
                } else {
                        h[i].privNF = ar5212GetNfHistMid(h[i].nfCalBuffer);
                }
        }
}   
 
static uint16_t
ar5416GetDefaultNF(struct ath_hal *ah, const struct ieee80211_channel *chan)
{
        struct ar5416NfLimits *limit;
 
        if (!chan || IEEE80211_IS_CHAN_2GHZ(chan))
                limit = &AH5416(ah)->nf_2g;
        else
                limit = &AH5416(ah)->nf_5g;
 
        return limit->nominal;
}
 
static void
ar5416SanitizeNF(struct ath_hal *ah, int16_t *nf)
{
 
        struct ar5416NfLimits *limit;
        int i;
 
        if (IEEE80211_IS_CHAN_2GHZ(AH_PRIVATE(ah)->ah_curchan))
                limit = &AH5416(ah)->nf_2g;
        else
                limit = &AH5416(ah)->nf_5g;
 
        for (i = 0; i < AR5416_NUM_NF_READINGS; i++) {
                if (!nf[i])
                        continue;
 
                if (nf[i] > limit->max) {
                        HALDEBUG(ah, HAL_DEBUG_NFCAL,
                                  "NF[%d] (%d) > MAX (%d), correcting to MAX\n",
                                  i, nf[i], limit->max);
                        nf[i] = limit->max;
                } else if (nf[i] < limit->min) {
                        HALDEBUG(ah, HAL_DEBUG_NFCAL,
                                  "NF[%d] (%d) < MIN (%d), correcting to NOM\n",
                                  i, nf[i], limit->min);
                        nf[i] = limit->nominal;
                }
        }
}
 
/*
 * Read the NF and check it against the noise floor threshold
 *
 * Return 0 if the NF calibration hadn't finished, 0 if it was
 * invalid, or > 0 for a valid NF reading.
 */
static int16_t
ar5416GetNf(struct ath_hal *ah, struct ieee80211_channel *chan)
{
        int16_t nf, nfThresh;
        int i;
        int retval = 0;
 
        if (ar5212IsNFCalInProgress(ah)) {
                HALDEBUG(ah, HAL_DEBUG_ANY,
                    "%s: NF didn't complete in calibration window\n", __func__);
                nf = 0;
                retval = -1;    /* NF didn't finish */
        } else {
                /* Finished NF cal, check against threshold */
                int16_t nfarray[NUM_NOISEFLOOR_READINGS] = { 0 };
                HAL_CHANNEL_INTERNAL *ichan = ath_hal_checkchannel(ah, chan);
                        
                /* TODO - enhance for multiple chains and ext ch */
                ath_hal_getNoiseFloor(ah, nfarray);
                nf = nfarray[0];
                ar5416SanitizeNF(ah, nfarray);
                if (ar5416GetEepromNoiseFloorThresh(ah, chan, &nfThresh)) {
                        if (nf > nfThresh) {
                                HALDEBUG(ah, HAL_DEBUG_UNMASKABLE,
                                    "%s: noise floor failed detected; "
                                    "detected %d, threshold %d\n", __func__,
                                    nf, nfThresh);
                                /*
                                 * NB: Don't discriminate 2.4 vs 5Ghz, if this
                                 *     happens it indicates a problem regardless
                                 *     of the band.
                                 */
                                chan->ic_state |= IEEE80211_CHANSTATE_CWINT;
                                nf = 0;
                                retval = 0;
                        }
                } else {
                        nf = 0;
                        retval = 0;
                }
                /* Update MIMO channel statistics, regardless of validity or not (for now) */
                for (i = 0; i < 3; i++) {
                        ichan->noiseFloorCtl[i] = nfarray[i];
                        ichan->noiseFloorExt[i] = nfarray[i + 3];
                }
                ichan->privFlags |= CHANNEL_MIMO_NF_VALID;
 
                ar5416UpdateNFHistBuff(ah, AH5416(ah)->ah_cal.nfCalHist, nfarray);
                ichan->rawNoiseFloor = nf;
                retval = nf;
        }
        return retval;
}