calib.c

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/*
 * 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"
#include <linux/export.h>

/* Common calibration code */


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;
}

s16 ath9k_hw_getchan_noise(struct ath_hw *ah, struct ath9k_channel *chan)
{
    s8 noise = ATH_DEFAULT_NOISE_FLOOR;

    if (chan && chan->noisefloor) {
        s8 delta = chan->noisefloor -
               ath9k_hw_get_default_nf(ah, chan);
        if (delta > 0)
            noise += delta;
    }
    return noise;
}
EXPORT_SYMBOL(ath9k_hw_getchan_noise);

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 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) && !IS_CHAN_HT40(ah->curchan)))
            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, 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, CALIBRATE, "Calibration state incorrect, %d\n",
            currCal->calState);
        return true;
    }

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

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

        if (nf[i] > limit->max) {
            ath_dbg(common, CALIBRATE,
                "NF[%d] (%d) > MAX (%d), correcting to MAX\n",
                i, nf[i], limit->max);
            nf[i] = limit->max;
        } else if (nf[i] < limit->min) {
            ath_dbg(common, 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, 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, CALIBRATE,
            "noise floor failed detected; detected %d, threshold %d\n",
            nf, nfThresh);
        chan->channelFlags |= CHANNEL_CW_INT;
    }

    if (!caldata) {
        chan->noisefloor = nf;
        ah->noise = ath9k_hw_getchan_noise(ah, chan);
        return false;
    }

    h = caldata->nfCalHist;
    caldata->nfcal_pending = false;
    ath9k_hw_update_nfcal_hist_buffer(ah, caldata, nfarray);
    chan->noisefloor = h[0].privNF;
    ah->noise = ath9k_hw_getchan_noise(ah, chan);
    return true;
}
EXPORT_SYMBOL(ath9k_hw_getnf);

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);