/*
 * 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,  7,  1  }, /* lvl 8 */
        {  7,  8,  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 */
        {  7,  0  }, /* lvl 7 (only for high rssi) */
        {  8,  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 (!ah->curchan)
                return;

        aniState = &ah->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->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),
                ATH9K_ANI_RSSI_THR_LOW,
                ATH9K_ANI_RSSI_THR_HIGH);

        if (AR_SREV_9100(ah) && immunityLevel < ATH9K_ANI_OFDM_DEF_LEVEL)
                immunityLevel = ATH9K_ANI_OFDM_DEF_LEVEL;

        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) <= ATH9K_ANI_RSSI_THR_HIGH)
                weak_sig = true;
        /*
         * Newer chipsets are better at dealing with high PHY error counts -
         * keep weak signal detection enabled when no RSSI threshold is
         * available to determine if it is needed (mode != STA)
         */
        else if (AR_SREV_9300_20_OR_LATER(ah) &&
                 ah->opmode != NL80211_IFTYPE_STATION)
                weak_sig = true;

        /* Older chipsets are more sensitive to high PHY error counts */
        else if (!AR_SREV_9300_20_OR_LATER(ah) &&
                 aniState->ofdmNoiseImmunityLevel >= 8)
                weak_sig = false;

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

        if (!AR_SREV_9300_20_OR_LATER(ah))
                return;

        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 (!ah->curchan)
                return;

        aniState = &ah->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->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), ATH9K_ANI_RSSI_THR_LOW,
                ATH9K_ANI_RSSI_THR_HIGH);

        if (AR_SREV_9100(ah) && immunityLevel < ATH9K_ANI_CCK_DEF_LEVEL)
                immunityLevel = ATH9K_ANI_CCK_DEF_LEVEL;

        if (ah->opmode == NL80211_IFTYPE_STATION &&
            BEACON_RSSI(ah) <= ATH9K_ANI_RSSI_THR_LOW &&
            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) || AR_SREV_9561(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 (!ah->curchan)
                return;

        aniState = &ah->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->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->ani;
        struct ath9k_channel *chan = ah->curchan;
        struct ath_common *common = ath9k_hw_common(ah);
        int ofdm_nil, cck_nil;

        if (!ah->curchan)
                return;

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

        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 is_scanning=%d ofdm:%d cck:%d\n",
                                ah->opmode,
                                chan->channel,
                                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 is_scanning=%d ofdm:%d cck:%d\n",
                        ah->opmode,
                        chan->channel,
                        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);

        ath9k_ani_restart(ah);
}

static bool ath9k_hw_ani_read_counters(struct ath_hw *ah)
{
        struct ath_common *common = ath9k_hw_common(ah);
        struct ar5416AniState *aniState = &ah->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 (!ah->curchan)
                return;

        aniState = &ah->ani;
        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_init(struct ath_hw *ah)
{
        struct ath_common *common = ath9k_hw_common(ah);
        struct ar5416AniState *ani = &ah->ani;

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

        if (AR_SREV_9300_20_OR_LATER(ah)) {
                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;
        } else {
                ah->config.ofdm_trig_high = ATH9K_ANI_OFDM_TRIG_HIGH_OLD;
                ah->config.ofdm_trig_low = ATH9K_ANI_OFDM_TRIG_LOW_OLD;
                ah->config.cck_trig_high = ATH9K_ANI_CCK_TRIG_HIGH_OLD;
                ah->config.cck_trig_low = ATH9K_ANI_CCK_TRIG_LOW_OLD;
        }

        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->ofdmWeakSigDetect = true;
        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;

        ath9k_ani_restart(ah);
        ath9k_enable_mib_counters(ah);
}