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

/* Common calibration code */

static int rcmp_i16(const void *x, const void *y)
{
        /* Sort in reverse order. */
        return *(int16_t *)y - *(int16_t *)x;
}

static int16_t ath9k_hw_get_nf_hist_mid(int16_t *nfCalBuffer)
{
        int16_t nfcal[ATH9K_NF_CAL_HIST_MAX];

        memcpy(nfcal, nfCalBuffer, sizeof(nfcal));
        sort(nfcal, ATH9K_NF_CAL_HIST_MAX, sizeof(int16_t), rcmp_i16, NULL);

        return nfcal[(ATH9K_NF_CAL_HIST_MAX - 1) >> 1];
}

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,
                                   int chain)
{
        s16 calib_nf = ath9k_hw_get_nf_limits(ah, chan)->cal[chain];

        if (calib_nf)
                return calib_nf;
        else
                return ath9k_hw_get_nf_limits(ah, chan)->nominal;
}

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

        if (nf) {
                s8 delta = nf - ATH9K_NF_CAL_NOISE_THRESH -
                           ath9k_hw_get_default_nf(ah, chan, 0);
                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,
                                (test_bit(NFCAL_INTF, &cal->cal_flags) ?
                                 "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 (!test_bit(NFCAL_INTF, &cal->cal_flags))
                                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)
                clear_bit(NFCAL_INTF, &cal->cal_flags);
}

static bool ath9k_hw_get_nf_thresh(struct ath_hw *ah,
                                   enum nl80211_band band,
                                   int16_t *nft)
{
        switch (band) {
        case NL80211_BAND_5GHZ:
                *nft = (int8_t)ah->eep_ops->get_eeprom(ah, EEP_NFTHRESH_5);
                break;
        case NL80211_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);

        ah->cal_start_time = jiffies;
        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 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;
        }

        currCal = ah->cal_list;
        do {
                ath_dbg(common, CALIBRATE, "Resetting Cal %d state for channel %u\n",
                        currCal->calData->calType,
                        ah->curchan->chan->center_freq);

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

                currCal = currCal->calNext;
        } while (currCal != ah->cal_list);

        return false;
}
EXPORT_SYMBOL(ath9k_hw_reset_calvalid);

void ath9k_hw_start_nfcal(struct ath_hw *ah, bool update)
{
        if (ah->caldata)
                set_bit(NFCAL_PENDING, &ah->caldata->cal_flags);

        REG_SET_BIT(ah, AR_PHY_AGC_CONTROL(ah),
                    AR_PHY_AGC_CONTROL_ENABLE_NF);

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

        REG_SET_BIT(ah, AR_PHY_AGC_CONTROL(ah), AR_PHY_AGC_CONTROL_NF);
}

int ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan)
{
        struct ath9k_nfcal_hist *h = NULL;
        unsigned i, j;
        u8 chainmask = (ah->rxchainmask << 3) | ah->rxchainmask;
        struct ath_common *common = ath9k_hw_common(ah);
        s16 default_nf = ath9k_hw_get_nf_limits(ah, chan)->nominal;
        u32 bb_agc_ctl = REG_READ(ah, AR_PHY_AGC_CONTROL(ah));

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

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

                        if ((i >= AR5416_MAX_CHAINS) && !IS_CHAN_HT40(chan))
                                continue;

                        if (ah->nf_override)
                                nfval = ah->nf_override;
                        else if (h)
                                nfval = h[i].privNF;
                        else {
                                /* Try to get calibrated noise floor value */
                                nfval =
                                    ath9k_hw_get_nf_limits(ah, chan)->cal[i];
                                if (nfval > -60 || nfval < -127)
                                        nfval = default_nf;
                        }

                        REG_RMW(ah, ah->nf_regs[i],
                                (((u32) nfval << 1) & 0x1ff), 0x1ff);
                }
        }

        /*
         * stop NF cal if ongoing to ensure NF load completes immediately
         * (or after end rx/tx frame if ongoing)
         */
        if (bb_agc_ctl & AR_PHY_AGC_CONTROL_NF) {
                REG_CLR_BIT(ah, AR_PHY_AGC_CONTROL(ah), AR_PHY_AGC_CONTROL_NF);
                REG_RMW_BUFFER_FLUSH(ah);
                ENABLE_REG_RMW_BUFFER(ah);
        }

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

        /*
         * Wait for load to complete, should be fast, a few 10s of us.
         * The max delay was changed from an original 250us to 22.2 msec.
         * This would increase timeout to the longest possible frame
         * (11n max length 22.1 msec)
         */
        for (j = 0; j < 22200; j++) {
                if ((REG_READ(ah, AR_PHY_AGC_CONTROL(ah)) &
                              AR_PHY_AGC_CONTROL_NF) == 0)
                        break;
                udelay(10);
        }

        /*
         * Restart NF so it can continue.
         */
        if (bb_agc_ctl & AR_PHY_AGC_CONTROL_NF) {
                ENABLE_REG_RMW_BUFFER(ah);
                if (bb_agc_ctl & AR_PHY_AGC_CONTROL_ENABLE_NF)
                        REG_SET_BIT(ah, AR_PHY_AGC_CONTROL(ah),
                                    AR_PHY_AGC_CONTROL_ENABLE_NF);
                if (bb_agc_ctl & AR_PHY_AGC_CONTROL_NO_UPDATE_NF)
                        REG_SET_BIT(ah, AR_PHY_AGC_CONTROL(ah),
                                    AR_PHY_AGC_CONTROL_NO_UPDATE_NF);
                REG_SET_BIT(ah, AR_PHY_AGC_CONTROL(ah), AR_PHY_AGC_CONTROL_NF);
                REG_RMW_BUFFER_FLUSH(ah);
        }

        /*
         * 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 == 22200) {
                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(ah)));
                return -ETIMEDOUT;
        }

        /*
         * 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_REG_RMW_BUFFER(ah);
        for (i = 0; i < NUM_NF_READINGS; i++) {
                if (chainmask & (1 << i)) {
                        if ((i >= AR5416_MAX_CHAINS) && !IS_CHAN_HT40(chan))
                                continue;

                        REG_RMW(ah, ah->nf_regs[i],
                                        (((u32) (-50) << 1) & 0x1ff), 0x1ff);
                }
        }
        REG_RMW_BUFFER_FLUSH(ah);

        return 0;
}
EXPORT_SYMBOL(ath9k_hw_loadnf);


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;

        if (REG_READ(ah, AR_PHY_AGC_CONTROL(ah)) & 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);
        }

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

        h = caldata->nfCalHist;
        clear_bit(NFCAL_PENDING, &caldata->cal_flags);
        ath9k_hw_update_nfcal_hist_buffer(ah, caldata, nfarray);
        chan->noisefloor = h[0].privNF;
        ah->noise = ath9k_hw_getchan_noise(ah, chan, chan->noisefloor);
        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;
        int i, j, k = 0;

        ah->caldata->channel = chan->channel;
        ah->caldata->channelFlags = chan->channelFlags;
        h = ah->caldata->nfCalHist;
        for (i = 0; i < NUM_NF_READINGS; i++) {
                h[i].currIndex = 0;
                h[i].privNF = ath9k_hw_get_default_nf(ah, chan, k);
                h[i].invalidNFcount = AR_PHY_CCA_FILTERWINDOW_LENGTH;
                for (j = 0; j < ATH9K_NF_CAL_HIST_MAX; j++)
                        h[i].nfCalBuffer[j] = h[i].privNF;
                if (++k >= AR5416_MAX_CHAINS)
                        k = 0;
        }
}


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 (!test_bit(NFCAL_PENDING, &caldata->cal_flags))
                ath9k_hw_start_nfcal(ah, true);
        else if (!(REG_READ(ah, AR_PHY_AGC_CONTROL(ah)) & AR_PHY_AGC_CONTROL_NF))
                ath9k_hw_getnf(ah, ah->curchan);

        set_bit(NFCAL_INTF, &caldata->cal_flags);
}
EXPORT_SYMBOL(ath9k_hw_bstuck_nfcal);