ani.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 <linux/kernel.h>
#include <linux/export.h>
#include "hw.h"
#include "hw-ops.h"

struct ani_ofdm_level_entry {
    int spur_immunity_level;
    int fir_step_level;
    int ofdm_weak_signal_on;
};

/* values here are relative to the INI */

/*
 * Legend:
 *
 * SI: Spur immunity
 * FS: FIR Step
 * WS: OFDM / CCK Weak Signal detection
 * MRC-CCK: Maximal Ratio Combining for CCK
 */

static const struct ani_ofdm_level_entry ofdm_level_table[] = {
    /* SI  FS  WS */
    {  0,  0,  1  }, /* lvl 0 */
    {  1,  1,  1  }, /* lvl 1 */
    {  2,  2,  1  }, /* lvl 2 */
    {  3,  2,  1  }, /* lvl 3  (default) */
    {  4,  3,  1  }, /* lvl 4 */
    {  5,  4,  1  }, /* lvl 5 */
    {  6,  5,  1  }, /* lvl 6 */
    {  7,  6,  1  }, /* lvl 7 */
    {  7,  6,  0  }, /* lvl 8 */
    {  7,  7,  0  }  /* lvl 9 */
};
#define ATH9K_ANI_OFDM_NUM_LEVEL \
    ARRAY_SIZE(ofdm_level_table)
#define ATH9K_ANI_OFDM_MAX_LEVEL \
    (ATH9K_ANI_OFDM_NUM_LEVEL-1)
#define ATH9K_ANI_OFDM_DEF_LEVEL \
    3 /* default level - matches the INI settings */

/*
 * MRC (Maximal Ratio Combining) has always been used with multi-antenna ofdm.
 * With OFDM for single stream you just add up all antenna inputs, you're
 * only interested in what you get after FFT. Signal aligment is also not
 * required for OFDM because any phase difference adds up in the frequency
 * domain.
 *
 * MRC requires extra work for use with CCK. You need to align the antenna
 * signals from the different antenna before you can add the signals together.
 * You need aligment of signals as CCK is in time domain, so addition can cancel
 * your signal completely if phase is 180 degrees (think of adding sine waves).
 * You also need to remove noise before the addition and this is where ANI
 * MRC CCK comes into play. One of the antenna inputs may be stronger but
 * lower SNR, so just adding after alignment can be dangerous.
 *
 * Regardless of alignment in time, the antenna signals add constructively after
 * FFT and improve your reception. For more information:
 *
 * http://en.wikipedia.org/wiki/Maximal-ratio_combining
 */

struct ani_cck_level_entry {
    int fir_step_level;
    int mrc_cck_on;
};

static const struct ani_cck_level_entry cck_level_table[] = {
    /* FS  MRC-CCK  */
    {  0,  1  }, /* lvl 0 */
    {  1,  1  }, /* lvl 1 */
    {  2,  1  }, /* lvl 2  (default) */
    {  3,  1  }, /* lvl 3 */
    {  4,  0  }, /* lvl 4 */
    {  5,  0  }, /* lvl 5 */
    {  6,  0  }, /* lvl 6 */
    {  6,  0  }, /* lvl 7 (only for high rssi) */
    {  7,  0  }  /* lvl 8 (only for high rssi) */
};

#define ATH9K_ANI_CCK_NUM_LEVEL \
    ARRAY_SIZE(cck_level_table)
#define ATH9K_ANI_CCK_MAX_LEVEL \
    (ATH9K_ANI_CCK_NUM_LEVEL-1)
#define ATH9K_ANI_CCK_MAX_LEVEL_LOW_RSSI \
    (ATH9K_ANI_CCK_NUM_LEVEL-3)
#define ATH9K_ANI_CCK_DEF_LEVEL \
    2 /* default level - matches the INI settings */

static void ath9k_hw_update_mibstats(struct ath_hw *ah,
                     struct ath9k_mib_stats *stats)
{
    stats->ackrcv_bad += REG_READ(ah, AR_ACK_FAIL);
    stats->rts_bad += REG_READ(ah, AR_RTS_FAIL);
    stats->fcs_bad += REG_READ(ah, AR_FCS_FAIL);
    stats->rts_good += REG_READ(ah, AR_RTS_OK);
    stats->beacons += REG_READ(ah, AR_BEACON_CNT);
}

static void ath9k_ani_restart(struct ath_hw *ah)
{
    struct ar5416AniState *aniState;

    if (!DO_ANI(ah))
        return;

    aniState = &ah->curchan->ani;
    aniState->listenTime = 0;

    ENABLE_REGWRITE_BUFFER(ah);

    REG_WRITE(ah, AR_PHY_ERR_1, 0);
    REG_WRITE(ah, AR_PHY_ERR_2, 0);
    REG_WRITE(ah, AR_PHY_ERR_MASK_1, AR_PHY_ERR_OFDM_TIMING);
    REG_WRITE(ah, AR_PHY_ERR_MASK_2, AR_PHY_ERR_CCK_TIMING);

    REGWRITE_BUFFER_FLUSH(ah);

    ath9k_hw_update_mibstats(ah, &ah->ah_mibStats);

    aniState->ofdmPhyErrCount = 0;
    aniState->cckPhyErrCount = 0;
}

/* Adjust the OFDM Noise Immunity Level */
static void ath9k_hw_set_ofdm_nil(struct ath_hw *ah, u8 immunityLevel,
                  bool scan)
{
    struct ar5416AniState *aniState = &ah->curchan->ani;
    struct ath_common *common = ath9k_hw_common(ah);
    const struct ani_ofdm_level_entry *entry_ofdm;
    const struct ani_cck_level_entry *entry_cck;
    bool weak_sig;

    ath_dbg(common, ANI, "**** ofdmlevel %d=>%d, rssi=%d[lo=%d hi=%d]\n",
        aniState->ofdmNoiseImmunityLevel,
        immunityLevel, BEACON_RSSI(ah),
        aniState->rssiThrLow, aniState->rssiThrHigh);

    if (!scan)
        aniState->ofdmNoiseImmunityLevel = immunityLevel;

    entry_ofdm = &ofdm_level_table[aniState->ofdmNoiseImmunityLevel];
    entry_cck = &cck_level_table[aniState->cckNoiseImmunityLevel];

    if (aniState->spurImmunityLevel != entry_ofdm->spur_immunity_level)
        ath9k_hw_ani_control(ah,
                     ATH9K_ANI_SPUR_IMMUNITY_LEVEL,
                     entry_ofdm->spur_immunity_level);

    if (aniState->firstepLevel != entry_ofdm->fir_step_level &&
        entry_ofdm->fir_step_level >= entry_cck->fir_step_level)
        ath9k_hw_ani_control(ah,
                     ATH9K_ANI_FIRSTEP_LEVEL,
                     entry_ofdm->fir_step_level);

    weak_sig = entry_ofdm->ofdm_weak_signal_on;
    if (ah->opmode == NL80211_IFTYPE_STATION &&
        BEACON_RSSI(ah) <= aniState->rssiThrHigh)
        weak_sig = true;

    if (aniState->ofdmWeakSigDetect != weak_sig)
            ath9k_hw_ani_control(ah,
                ATH9K_ANI_OFDM_WEAK_SIGNAL_DETECTION,
                entry_ofdm->ofdm_weak_signal_on);

    if (aniState->ofdmNoiseImmunityLevel >= ATH9K_ANI_OFDM_DEF_LEVEL) {
        ah->config.ofdm_trig_high = ATH9K_ANI_OFDM_TRIG_HIGH;
        ah->config.ofdm_trig_low = ATH9K_ANI_OFDM_TRIG_LOW_ABOVE_INI;
    } else {
        ah->config.ofdm_trig_high = ATH9K_ANI_OFDM_TRIG_HIGH_BELOW_INI;
        ah->config.ofdm_trig_low = ATH9K_ANI_OFDM_TRIG_LOW;
    }
}

static void ath9k_hw_ani_ofdm_err_trigger(struct ath_hw *ah)
{
    struct ar5416AniState *aniState;

    if (!DO_ANI(ah))
        return;

    aniState = &ah->curchan->ani;

    if (aniState->ofdmNoiseImmunityLevel < ATH9K_ANI_OFDM_MAX_LEVEL)
        ath9k_hw_set_ofdm_nil(ah, aniState->ofdmNoiseImmunityLevel + 1, false);
}

/*
 * Set the ANI settings to match an CCK level.
 */
static void ath9k_hw_set_cck_nil(struct ath_hw *ah, u_int8_t immunityLevel,
                 bool scan)
{
    struct ar5416AniState *aniState = &ah->curchan->ani;
    struct ath_common *common = ath9k_hw_common(ah);
    const struct ani_ofdm_level_entry *entry_ofdm;
    const struct ani_cck_level_entry *entry_cck;

    ath_dbg(common, ANI, "**** ccklevel %d=>%d, rssi=%d[lo=%d hi=%d]\n",
        aniState->cckNoiseImmunityLevel, immunityLevel,
        BEACON_RSSI(ah), aniState->rssiThrLow,
        aniState->rssiThrHigh);

    if (ah->opmode == NL80211_IFTYPE_STATION &&
        BEACON_RSSI(ah) <= aniState->rssiThrLow &&
        immunityLevel > ATH9K_ANI_CCK_MAX_LEVEL_LOW_RSSI)
        immunityLevel = ATH9K_ANI_CCK_MAX_LEVEL_LOW_RSSI;

    if (!scan)
        aniState->cckNoiseImmunityLevel = immunityLevel;

    entry_ofdm = &ofdm_level_table[aniState->ofdmNoiseImmunityLevel];
    entry_cck = &cck_level_table[aniState->cckNoiseImmunityLevel];

    if (aniState->firstepLevel != entry_cck->fir_step_level &&
        entry_cck->fir_step_level >= entry_ofdm->fir_step_level)
        ath9k_hw_ani_control(ah,
                     ATH9K_ANI_FIRSTEP_LEVEL,
                     entry_cck->fir_step_level);

    /* Skip MRC CCK for pre AR9003 families */
    if (!AR_SREV_9300_20_OR_LATER(ah) || AR_SREV_9485(ah) || AR_SREV_9565(ah))
        return;

    if (aniState->mrcCCK != entry_cck->mrc_cck_on)
        ath9k_hw_ani_control(ah,
                     ATH9K_ANI_MRC_CCK,
                     entry_cck->mrc_cck_on);
}

static void ath9k_hw_ani_cck_err_trigger(struct ath_hw *ah)
{
    struct ar5416AniState *aniState;

    if (!DO_ANI(ah))
        return;

    aniState = &ah->curchan->ani;

    if (aniState->cckNoiseImmunityLevel < ATH9K_ANI_CCK_MAX_LEVEL)
        ath9k_hw_set_cck_nil(ah, aniState->cckNoiseImmunityLevel + 1,
                     false);
}

/*
 * only lower either OFDM or CCK errors per turn
 * we lower the other one next time
 */
static void ath9k_hw_ani_lower_immunity(struct ath_hw *ah)
{
    struct ar5416AniState *aniState;

    aniState = &ah->curchan->ani;

    /* lower OFDM noise immunity */
    if (aniState->ofdmNoiseImmunityLevel > 0 &&
        (aniState->ofdmsTurn || aniState->cckNoiseImmunityLevel == 0)) {
        ath9k_hw_set_ofdm_nil(ah, aniState->ofdmNoiseImmunityLevel - 1,
                      false);
        return;
    }

    /* lower CCK noise immunity */
    if (aniState->cckNoiseImmunityLevel > 0)
        ath9k_hw_set_cck_nil(ah, aniState->cckNoiseImmunityLevel - 1,
                     false);
}

/*
 * Restore the ANI parameters in the HAL and reset the statistics.
 * This routine should be called for every hardware reset and for
 * every channel change.
 */
void ath9k_ani_reset(struct ath_hw *ah, bool is_scanning)
{
    struct ar5416AniState *aniState = &ah->curchan->ani;
    struct ath9k_channel *chan = ah->curchan;
    struct ath_common *common = ath9k_hw_common(ah);
    int ofdm_nil, cck_nil;

    if (!DO_ANI(ah))
        return;

    BUG_ON(aniState == NULL);
    ah->stats.ast_ani_reset++;

    /* only allow a subset of functions in AP mode */
    if (ah->opmode == NL80211_IFTYPE_AP) {
        if (IS_CHAN_2GHZ(chan)) {
            ah->ani_function = (ATH9K_ANI_SPUR_IMMUNITY_LEVEL |
                        ATH9K_ANI_FIRSTEP_LEVEL);
            if (AR_SREV_9300_20_OR_LATER(ah))
                ah->ani_function |= ATH9K_ANI_MRC_CCK;
        } else
            ah->ani_function = 0;
    }

    /* always allow mode (on/off) to be controlled */
    ah->ani_function |= ATH9K_ANI_MODE;

    ofdm_nil = max_t(int, ATH9K_ANI_OFDM_DEF_LEVEL,
             aniState->ofdmNoiseImmunityLevel);
    cck_nil = max_t(int, ATH9K_ANI_CCK_DEF_LEVEL,
             aniState->cckNoiseImmunityLevel);

    if (is_scanning ||
        (ah->opmode != NL80211_IFTYPE_STATION &&
         ah->opmode != NL80211_IFTYPE_ADHOC)) {
        /*
         * If we're scanning or in AP mode, the defaults (ini)
         * should be in place. For an AP we assume the historical
         * levels for this channel are probably outdated so start
         * from defaults instead.
         */
        if (aniState->ofdmNoiseImmunityLevel !=
            ATH9K_ANI_OFDM_DEF_LEVEL ||
            aniState->cckNoiseImmunityLevel !=
            ATH9K_ANI_CCK_DEF_LEVEL) {
            ath_dbg(common, ANI,
                "Restore defaults: opmode %u chan %d Mhz/0x%x is_scanning=%d ofdm:%d cck:%d\n",
                ah->opmode,
                chan->channel,
                chan->channelFlags,
                is_scanning,
                aniState->ofdmNoiseImmunityLevel,
                aniState->cckNoiseImmunityLevel);

            ofdm_nil = ATH9K_ANI_OFDM_DEF_LEVEL;
            cck_nil = ATH9K_ANI_CCK_DEF_LEVEL;
        }
    } else {
        /*
         * restore historical levels for this channel
         */
        ath_dbg(common, ANI,
            "Restore history: opmode %u chan %d Mhz/0x%x is_scanning=%d ofdm:%d cck:%d\n",
            ah->opmode,
            chan->channel,
            chan->channelFlags,
            is_scanning,
            aniState->ofdmNoiseImmunityLevel,
            aniState->cckNoiseImmunityLevel);
    }
    ath9k_hw_set_ofdm_nil(ah, ofdm_nil, is_scanning);
    ath9k_hw_set_cck_nil(ah, cck_nil, is_scanning);

    /*
     * enable phy counters if hw supports or if not, enable phy
     * interrupts (so we can count each one)
     */
    ath9k_ani_restart(ah);

    ENABLE_REGWRITE_BUFFER(ah);

    REG_WRITE(ah, AR_PHY_ERR_MASK_1, AR_PHY_ERR_OFDM_TIMING);
    REG_WRITE(ah, AR_PHY_ERR_MASK_2, AR_PHY_ERR_CCK_TIMING);

    REGWRITE_BUFFER_FLUSH(ah);
}

static bool ath9k_hw_ani_read_counters(struct ath_hw *ah)
{
    struct ath_common *common = ath9k_hw_common(ah);
    struct ar5416AniState *aniState = &ah->curchan->ani;
    u32 phyCnt1, phyCnt2;
    int32_t listenTime;

    ath_hw_cycle_counters_update(common);
    listenTime = ath_hw_get_listen_time(common);

    if (listenTime <= 0) {
        ah->stats.ast_ani_lneg_or_lzero++;
        ath9k_ani_restart(ah);
        return false;
    }

    aniState->listenTime += listenTime;

    ath9k_hw_update_mibstats(ah, &ah->ah_mibStats);

    phyCnt1 = REG_READ(ah, AR_PHY_ERR_1);
    phyCnt2 = REG_READ(ah, AR_PHY_ERR_2);

    ah->stats.ast_ani_ofdmerrs += phyCnt1 - aniState->ofdmPhyErrCount;
    aniState->ofdmPhyErrCount = phyCnt1;

    ah->stats.ast_ani_cckerrs += phyCnt2 - aniState->cckPhyErrCount;
    aniState->cckPhyErrCount = phyCnt2;

    return true;
}

void ath9k_hw_ani_monitor(struct ath_hw *ah, struct ath9k_channel *chan)
{
    struct ar5416AniState *aniState;
    struct ath_common *common = ath9k_hw_common(ah);
    u32 ofdmPhyErrRate, cckPhyErrRate;

    if (!DO_ANI(ah))
        return;

    aniState = &ah->curchan->ani;
    if (WARN_ON(!aniState))
        return;

    if (!ath9k_hw_ani_read_counters(ah))
        return;

    ofdmPhyErrRate = aniState->ofdmPhyErrCount * 1000 /
             aniState->listenTime;
    cckPhyErrRate =  aniState->cckPhyErrCount * 1000 /
             aniState->listenTime;

    ath_dbg(common, ANI,
        "listenTime=%d OFDM:%d errs=%d/s CCK:%d errs=%d/s ofdm_turn=%d\n",
        aniState->listenTime,
        aniState->ofdmNoiseImmunityLevel,
        ofdmPhyErrRate, aniState->cckNoiseImmunityLevel,
        cckPhyErrRate, aniState->ofdmsTurn);

    if (aniState->listenTime > ah->aniperiod) {
        if (cckPhyErrRate < ah->config.cck_trig_low &&
            ofdmPhyErrRate < ah->config.ofdm_trig_low) {
            ath9k_hw_ani_lower_immunity(ah);
            aniState->ofdmsTurn = !aniState->ofdmsTurn;
        } else if (ofdmPhyErrRate > ah->config.ofdm_trig_high) {
            ath9k_hw_ani_ofdm_err_trigger(ah);
            aniState->ofdmsTurn = false;
        } else if (cckPhyErrRate > ah->config.cck_trig_high) {
            ath9k_hw_ani_cck_err_trigger(ah);
            aniState->ofdmsTurn = true;
        }
        ath9k_ani_restart(ah);
    }
}
EXPORT_SYMBOL(ath9k_hw_ani_monitor);

void ath9k_enable_mib_counters(struct ath_hw *ah)
{
    struct ath_common *common = ath9k_hw_common(ah);

    ath_dbg(common, ANI, "Enable MIB counters\n");

    ath9k_hw_update_mibstats(ah, &ah->ah_mibStats);

    ENABLE_REGWRITE_BUFFER(ah);

    REG_WRITE(ah, AR_FILT_OFDM, 0);
    REG_WRITE(ah, AR_FILT_CCK, 0);
    REG_WRITE(ah, AR_MIBC,
          ~(AR_MIBC_COW | AR_MIBC_FMC | AR_MIBC_CMC | AR_MIBC_MCS)
          & 0x0f);
    REG_WRITE(ah, AR_PHY_ERR_MASK_1, AR_PHY_ERR_OFDM_TIMING);
    REG_WRITE(ah, AR_PHY_ERR_MASK_2, AR_PHY_ERR_CCK_TIMING);

    REGWRITE_BUFFER_FLUSH(ah);
}

/* Freeze the MIB counters, get the stats and then clear them */
void ath9k_hw_disable_mib_counters(struct ath_hw *ah)
{
    struct ath_common *common = ath9k_hw_common(ah);

    ath_dbg(common, ANI, "Disable MIB counters\n");

    REG_WRITE(ah, AR_MIBC, AR_MIBC_FMC);
    ath9k_hw_update_mibstats(ah, &ah->ah_mibStats);
    REG_WRITE(ah, AR_MIBC, AR_MIBC_CMC);
    REG_WRITE(ah, AR_FILT_OFDM, 0);
    REG_WRITE(ah, AR_FILT_CCK, 0);
}
EXPORT_SYMBOL(ath9k_hw_disable_mib_counters);

void ath9k_hw_ani_setup(struct ath_hw *ah)
{
    int i;

    static const int totalSizeDesired[] = { -55, -55, -55, -55, -62 };
    static const int coarseHigh[] = { -14, -14, -14, -14, -12 };
    static const int coarseLow[] = { -64, -64, -64, -64, -70 };
    static const int firpwr[] = { -78, -78, -78, -78, -80 };

    for (i = 0; i < 5; i++) {
        ah->totalSizeDesired[i] = totalSizeDesired[i];
        ah->coarse_high[i] = coarseHigh[i];
        ah->coarse_low[i] = coarseLow[i];
        ah->firpwr[i] = firpwr[i];
    }
}

void ath9k_hw_ani_init(struct ath_hw *ah)
{
    struct ath_common *common = ath9k_hw_common(ah);
    int i;

    ath_dbg(common, ANI, "Initialize ANI\n");

    ah->config.ofdm_trig_high = ATH9K_ANI_OFDM_TRIG_HIGH;
    ah->config.ofdm_trig_low = ATH9K_ANI_OFDM_TRIG_LOW;

    ah->config.cck_trig_high = ATH9K_ANI_CCK_TRIG_HIGH;
    ah->config.cck_trig_low = ATH9K_ANI_CCK_TRIG_LOW;

    for (i = 0; i < ARRAY_SIZE(ah->channels); i++) {
        struct ath9k_channel *chan = &ah->channels[i];
        struct ar5416AniState *ani = &chan->ani;

        ani->spurImmunityLevel = ATH9K_ANI_SPUR_IMMUNE_LVL;

        ani->firstepLevel = ATH9K_ANI_FIRSTEP_LVL;

        ani->mrcCCK = AR_SREV_9300_20_OR_LATER(ah) ? true : false;

        ani->ofdmsTurn = true;

        ani->rssiThrHigh = ATH9K_ANI_RSSI_THR_HIGH;
        ani->rssiThrLow = ATH9K_ANI_RSSI_THR_LOW;
        ani->ofdmWeakSigDetect = ATH9K_ANI_USE_OFDM_WEAK_SIG;
        ani->cckNoiseImmunityLevel = ATH9K_ANI_CCK_DEF_LEVEL;
        ani->ofdmNoiseImmunityLevel = ATH9K_ANI_OFDM_DEF_LEVEL;
    }

    /*
     * since we expect some ongoing maintenance on the tables, let's sanity
     * check here default level should not modify INI setting.
     */
    ah->aniperiod = ATH9K_ANI_PERIOD;
    ah->config.ani_poll_interval = ATH9K_ANI_POLLINTERVAL;

    if (ah->config.enable_ani)
        ah->proc_phyerr |= HAL_PROCESS_ANI;

    ath9k_ani_restart(ah);
    ath9k_enable_mib_counters(ah);
}