/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 2002-2004 Sam Leffler, Errno Consulting
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer,
 * without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 * similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
 * redistribution must be conditioned upon including a substantially
 * similar Disclaimer requirement for further binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 * of any contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGES.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/stream.h>
#include <sys/termio.h>
#include <sys/errno.h>
#include <sys/file.h>
#include <sys/cmn_err.h>
#include <sys/stropts.h>
#include <sys/strsubr.h>
#include <sys/strtty.h>
#include <sys/kbio.h>
#include <sys/cred.h>
#include <sys/stat.h>
#include <sys/consdev.h>
#include <sys/kmem.h>
#include <sys/modctl.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/pci.h>
#include <sys/errno.h>
#include <sys/dlpi.h>
#include <sys/ethernet.h>
#include <sys/list.h>
#include <sys/byteorder.h>
#include <sys/strsun.h>
#include <inet/common.h>
#include <inet/nd.h>
#include <inet/mi.h>
#include <inet/wifi_ioctl.h>
#include "ath_hal.h"
#include "ath_impl.h"
#include "ath_rate.h"

void
ath_rate_update(ath_t *asc, struct ieee80211_node *in, int32_t rate)
{
        struct ath_node *an = ATH_NODE(in);
        const HAL_RATE_TABLE *rt = asc->asc_currates;
        uint8_t rix;

        ASSERT(rt != NULL);

        in->in_txrate = rate;

        /* management/control frames always go at the lowest speed */
        an->an_tx_mgtrate = rt->info[0].rateCode;
        an->an_tx_mgtratesp = an->an_tx_mgtrate | rt->info[0].shortPreamble;
        ATH_DEBUG((ATH_DBG_RATE, "ath: ath_rate_update(): "
            "mgtrate=%d mgtratesp=%d\n",
            an->an_tx_mgtrate, an->an_tx_mgtratesp));
        /*
         * Before associating a node has no rate set setup
         * so we can't calculate any transmit codes to use.
         * This is ok since we should never be sending anything
         * but management frames and those always go at the
         * lowest hardware rate.
         */
        if (in->in_rates.ir_nrates == 0)
                goto done;
        an->an_tx_rix0 = asc->asc_rixmap[
            in->in_rates.ir_rates[rate] & IEEE80211_RATE_VAL];
        an->an_tx_rate0 = rt->info[an->an_tx_rix0].rateCode;
        an->an_tx_rate0sp = an->an_tx_rate0 |
            rt->info[an->an_tx_rix0].shortPreamble;
        if (asc->asc_mrretry) {
                /*
                 * Hardware supports multi-rate retry; setup two
                 * step-down retry rates and make the lowest rate
                 * be the ``last chance''.  We use 4, 2, 2, 2 tries
                 * respectively (4 is set here, the rest are fixed
                 * in the xmit routine).
                 */
                an->an_tx_try0 = 1 + 3;         /* 4 tries at rate 0 */
                if (--rate >= 0) {
                        rix = asc->asc_rixmap[
                            in->in_rates.ir_rates[rate]&IEEE80211_RATE_VAL];
                        an->an_tx_rate1 = rt->info[rix].rateCode;
                        an->an_tx_rate1sp = an->an_tx_rate1 |
                            rt->info[rix].shortPreamble;
                } else {
                        an->an_tx_rate1 = an->an_tx_rate1sp = 0;
                }
                if (--rate >= 0) {
                        rix = asc->asc_rixmap[
                            in->in_rates.ir_rates[rate]&IEEE80211_RATE_VAL];
                        an->an_tx_rate2 = rt->info[rix].rateCode;
                        an->an_tx_rate2sp = an->an_tx_rate2 |
                            rt->info[rix].shortPreamble;
                } else {
                        an->an_tx_rate2 = an->an_tx_rate2sp = 0;
                }
                if (rate > 0) {
                        an->an_tx_rate3 = rt->info[0].rateCode;
                        an->an_tx_rate3sp =
                            an->an_tx_mgtrate | rt->info[0].shortPreamble;
                } else {
                        an->an_tx_rate3 = an->an_tx_rate3sp = 0;
                }
        } else {
                an->an_tx_try0 = ATH_TXMAXTRY;  /* max tries at rate 0 */
                an->an_tx_rate1 = an->an_tx_rate1sp = 0;
                an->an_tx_rate2 = an->an_tx_rate2sp = 0;
                an->an_tx_rate3 = an->an_tx_rate3sp = 0;
        }
done:
        an->an_tx_ok = an->an_tx_err = an->an_tx_retr = an->an_tx_upper = 0;
}


/*
 * Set the starting transmit rate for a node.
 */
void
ath_rate_ctl_start(ath_t *asc, struct ieee80211_node *in)
{
        ieee80211com_t *ic = (ieee80211com_t *)asc;
        int32_t srate;

        if (ic->ic_fixed_rate == IEEE80211_FIXED_RATE_NONE) {
                /*
                 * No fixed rate is requested. For 11b start with
                 * the highest negotiated rate; otherwise, for 11g
                 * and 11a, we start "in the middle" at 24Mb or 36Mb.
                 */
                srate = in->in_rates.ir_nrates - 1;
                if (asc->asc_curmode != IEEE80211_MODE_11B) {
                        /*
                         * Scan the negotiated rate set to find the
                         * closest rate.
                         */
                        /* NB: the rate set is assumed sorted */
                        for (; srate >= 0 && IEEE80211_RATE(srate) > 72;
                            srate--) {}
                }
        } else {
                /*
                 * A fixed rate is to be used; We know the rate is
                 * there because the rate set is checked when the
                 * station associates.
                 */
                /* NB: the rate set is assumed sorted */
                srate = in->in_rates.ir_nrates - 1;
                for (; srate >= 0 && IEEE80211_RATE(srate) != ic->ic_fixed_rate;
                    srate--) {}
        }
        ATH_DEBUG((ATH_DBG_RATE, "ath: ath_rate_ctl_start(): "
            "srate=%d rate=%d\n", srate, IEEE80211_RATE(srate)));
        ath_rate_update(asc, in, srate);
}

void
ath_rate_cb(void *arg, struct ieee80211_node *in)
{
        ath_rate_update((ath_t *)arg, in, 0);
}

/*
 * Reset the rate control state for each 802.11 state transition.
 */
void
ath_rate_ctl_reset(ath_t *asc, enum ieee80211_state state)
{
        ieee80211com_t *ic = (ieee80211com_t *)asc;
        struct ieee80211_node *in;

        if (ic->ic_opmode == IEEE80211_M_STA) {
                /*
                 * Reset local xmit state; this is really only
                 * meaningful when operating in station mode.
                 */
                in = (struct ieee80211_node *)ic->ic_bss;
                if (state == IEEE80211_S_RUN) {
                        ath_rate_ctl_start(asc, in);
                } else {
                        ath_rate_update(asc, in, 0);
                }
        } else {
                /*
                 * When operating as a station the node table holds
                 * the AP's that were discovered during scanning.
                 * For any other operating mode we want to reset the
                 * tx rate state of each node.
                 */
                ieee80211_iterate_nodes(&ic->ic_sta, ath_rate_cb, asc);
                ath_rate_update(asc, ic->ic_bss, 0);
        }
}


/*
 * Examine and potentially adjust the transmit rate.
 */
void
ath_rate_ctl(void *arg, struct ieee80211_node *in)
{
        ath_t *asc = arg;
        struct ath_node *an = ATH_NODE(in);
        struct ieee80211_rateset *rs = &in->in_rates;
        int32_t mod = 0, nrate, enough;

        /*
         * Rate control(very primitive version).
         */
        asc->asc_stats.ast_rate_calls++;

        enough = (an->an_tx_ok + an->an_tx_err >= 10);

        /* no packet reached -> down */
        if (an->an_tx_err > 0 && an->an_tx_ok == 0)
                mod = -1;

        /* all packets needs retry in average -> down */
        if (enough && an->an_tx_ok < an->an_tx_retr)
                mod = -1;

        /* no error and less than 10% of packets needs retry -> up */
        if (enough && an->an_tx_err == 0 && an->an_tx_ok > an->an_tx_retr * 10)
                mod = 1;

        nrate = in->in_txrate;
        switch (mod) {
        case 0:
                if (enough && an->an_tx_upper > 0)
                        an->an_tx_upper--;
                break;
        case -1:
                if (nrate > 0) {
                        nrate--;
                        asc->asc_stats.ast_rate_drop++;
                }
                an->an_tx_upper = 0;
                break;
        case 1:
                if (++an->an_tx_upper < 10)
                        break;
                an->an_tx_upper = 0;
                if (nrate + 1 < rs->ir_nrates) {
                        nrate++;
                        asc->asc_stats.ast_rate_raise++;
                }
                break;
        }

        if (nrate != in->in_txrate) {
                ATH_DEBUG((ATH_DBG_RATE, "ath: ath_rate_ctl(): %dM -> %dM "
                    "(%d ok, %d err, %d retr)\n",
                    (rs->ir_rates[in->in_txrate] & IEEE80211_RATE_VAL) / 2,
                    (rs->ir_rates[nrate] & IEEE80211_RATE_VAL) / 2,
                    an->an_tx_ok, an->an_tx_err, an->an_tx_retr));
                ath_rate_update(asc, in, nrate);
        } else if (enough)
                an->an_tx_ok = an->an_tx_err = an->an_tx_retr = 0;
}


/*
 * Read rate table from the HAL, and then
 * copy the table to the driver's data structure.
 */
void
ath_rate_setup(ath_t *asc, uint32_t mode)
{
        int32_t i;
        uint8_t maxrates;
        struct ieee80211_rateset *rs;
        struct ath_hal *ah = asc->asc_ah;
        ieee80211com_t *ic = (ieee80211com_t *)asc;
        const HAL_RATE_TABLE *rt;

        switch (mode) {
        case IEEE80211_MODE_11A:
                asc->asc_rates[mode] = ATH_HAL_GETRATETABLE(ah, HAL_MODE_11A);
                break;
        case IEEE80211_MODE_11B:
                asc->asc_rates[mode] = ATH_HAL_GETRATETABLE(ah, HAL_MODE_11B);
                break;
        case IEEE80211_MODE_11G:
                asc->asc_rates[mode] = ATH_HAL_GETRATETABLE(ah, HAL_MODE_11G);
                break;
        case IEEE80211_MODE_TURBO_A:
                asc->asc_rates[mode] = ATH_HAL_GETRATETABLE(ah, HAL_MODE_TURBO);
                break;
        case IEEE80211_MODE_TURBO_G:
                asc->asc_rates[mode] = ATH_HAL_GETRATETABLE(ah, HAL_MODE_108G);
                break;
        default:
                ATH_DEBUG((ATH_DBG_RATE, "ath: ath_rate_setup(): "
                    "invalid mode %u\n", mode));
                return;
        }

        rt = asc->asc_rates[mode];
        if (rt == NULL)
                return;
        if (rt->rateCount > IEEE80211_RATE_MAXSIZE) {
                ATH_DEBUG((ATH_DBG_RATE, "ath: ath_rate_setup(): "
                    "rate table too small (%u > %u)\n",
                    rt->rateCount, IEEE80211_RATE_MAXSIZE));
                maxrates = IEEE80211_RATE_MAXSIZE;
        } else
                maxrates = rt->rateCount;
        rs = &ic->ic_sup_rates[mode];
        for (i = 0; i < maxrates; i++)
                rs->ir_rates[i] = rt->info[i].dot11Rate;
        rs->ir_nrates = maxrates;
}