io/ath/ath_rate.c

/*
 * 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;
}