ath5k.c

Go to the documentation of this file.

/*
 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
 * Copyright (c) 2004-2005 Atheros Communications, Inc.
 * Copyright (c) 2006 Devicescape Software, Inc.
 * Copyright (c) 2007 Jiri Slaby <jirislaby@gmail.com>
 * Copyright (c) 2007 Luis R. Rodriguez <mcgrof@winlab.rutgers.edu>
 *
 * Modified for iPXE, July 2009, by Joshua Oreman <oremanj@rwcr.net>
 * Original from Linux kernel 2.6.30.
 *
 * 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.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * 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.
 *
 */

FILE_LICENCE ( BSD3 );
FILE_SECBOOT ( FORBIDDEN );

#include <stdlib.h>
#include <ipxe/malloc.h>
#include <ipxe/timer.h>
#include <ipxe/netdevice.h>
#include <ipxe/pci.h>
#include <ipxe/pci_io.h>

#include "base.h"
#include "reg.h"

#define ATH5K_CALIB_INTERVAL    10 /* Calibrate PHY every 10 seconds */
#define ATH5K_RETRIES           4  /* Number of times to retry packet sends */
#define ATH5K_DESC_ALIGN        16 /* Alignment for TX/RX descriptors */

/******************\
* Internal defines *
\******************/

/* Known PCI ids */
static struct pci_device_id ath5k_nics[] = {
        PCI_ROM(0x10b7, 0x0013, "rdag675", "3com 3CRDAG675", AR5K_AR5212),
        PCI_ROM(0x168c, 0x0007, "ath5210", "Atheros 5210", AR5K_AR5210),
        PCI_ROM(0x168c, 0x0011, "ath5311", "Atheros 5311 (AHB)", AR5K_AR5211),
        PCI_ROM(0x168c, 0x0012, "ath5211", "Atheros 5211", AR5K_AR5211),
        PCI_ROM(0x168c, 0x0013, "ath5212", "Atheros 5212", AR5K_AR5212),
        PCI_ROM(0x168c, 0x0014, "ath5212x14", "Atheros 5212 x14", AR5K_AR5212),
        PCI_ROM(0x168c, 0x0015, "ath5212x15", "Atheros 5212 x15", AR5K_AR5212),
        PCI_ROM(0x168c, 0x0016, "ath5212x16", "Atheros 5212 x16", AR5K_AR5212),
        PCI_ROM(0x168c, 0x0017, "ath5212x17", "Atheros 5212 x17", AR5K_AR5212),
        PCI_ROM(0x168c, 0x0018, "ath5212x18", "Atheros 5212 x18", AR5K_AR5212),
        PCI_ROM(0x168c, 0x0019, "ath5212x19", "Atheros 5212 x19", AR5K_AR5212),
        PCI_ROM(0x168c, 0x001a, "ath2413", "Atheros 2413 Griffin", AR5K_AR5212),
        PCI_ROM(0x168c, 0x001b, "ath5413", "Atheros 5413 Eagle", AR5K_AR5212),
        PCI_ROM(0x168c, 0x001c, "ath5212e", "Atheros 5212 PCI-E", AR5K_AR5212),
        PCI_ROM(0x168c, 0x001d, "ath2417", "Atheros 2417 Nala", AR5K_AR5212),
        PCI_ROM(0x168c, 0x0207, "ath5210e", "Atheros 5210 early", AR5K_AR5210),
        PCI_ROM(0x168c, 0x1014, "ath5212m", "Ath 5212 miniPCI", AR5K_AR5212),
        PCI_ROM(0xa727, 0x0013, "ath5212c","3com Ath 5212", AR5K_AR5212),
};

#define ATH5K_SPMBL_NO   1
#define ATH5K_SPMBL_YES  2
#define ATH5K_SPMBL_BOTH 3

static const struct {
        u16 bitrate;
        u8 short_pmbl;
        u8 hw_code;
} ath5k_rates[] = {
        { 10, ATH5K_SPMBL_BOTH, ATH5K_RATE_CODE_1M },
        { 20, ATH5K_SPMBL_NO, ATH5K_RATE_CODE_2M },
        { 55, ATH5K_SPMBL_NO, ATH5K_RATE_CODE_5_5M },
        { 110, ATH5K_SPMBL_NO, ATH5K_RATE_CODE_11M },
        { 60, ATH5K_SPMBL_BOTH, ATH5K_RATE_CODE_6M },
        { 90, ATH5K_SPMBL_BOTH, ATH5K_RATE_CODE_9M },
        { 120, ATH5K_SPMBL_BOTH, ATH5K_RATE_CODE_12M },
        { 180, ATH5K_SPMBL_BOTH, ATH5K_RATE_CODE_18M },
        { 240, ATH5K_SPMBL_BOTH, ATH5K_RATE_CODE_24M },
        { 360, ATH5K_SPMBL_BOTH, ATH5K_RATE_CODE_36M },
        { 480, ATH5K_SPMBL_BOTH, ATH5K_RATE_CODE_48M },
        { 540, ATH5K_SPMBL_BOTH, ATH5K_RATE_CODE_54M },
        { 20, ATH5K_SPMBL_YES, ATH5K_RATE_CODE_2M | AR5K_SET_SHORT_PREAMBLE },
        { 55, ATH5K_SPMBL_YES, ATH5K_RATE_CODE_5_5M | AR5K_SET_SHORT_PREAMBLE },
        { 110, ATH5K_SPMBL_YES, ATH5K_RATE_CODE_11M | AR5K_SET_SHORT_PREAMBLE },
        { 0, 0, 0 },
};

#define ATH5K_NR_RATES 15

/*
 * Prototypes - PCI stack related functions
 */
static int              ath5k_probe(struct pci_device *pdev);
static void             ath5k_remove(struct pci_device *pdev);

struct pci_driver ath5k_pci_driver __pci_driver = {
        .ids            = ath5k_nics,
        .id_count       = sizeof(ath5k_nics) / sizeof(ath5k_nics[0]),
        .probe          = ath5k_probe,
        .remove         = ath5k_remove,
};



/*
 * Prototypes - MAC 802.11 stack related functions
 */
static int ath5k_tx(struct net80211_device *dev, struct io_buffer *skb);
static int ath5k_reset(struct ath5k_softc *sc, struct net80211_channel *chan);
static int ath5k_reset_wake(struct ath5k_softc *sc);
static int ath5k_start(struct net80211_device *dev);
static void ath5k_stop(struct net80211_device *dev);
static int ath5k_config(struct net80211_device *dev, int changed);
static void ath5k_poll(struct net80211_device *dev);
static void ath5k_irq(struct net80211_device *dev, int enable);

static struct net80211_device_operations ath5k_ops = {
        .open           = ath5k_start,
        .close          = ath5k_stop,
        .transmit       = ath5k_tx,
        .poll           = ath5k_poll,
        .irq            = ath5k_irq,
        .config         = ath5k_config,
};

/*
 * Prototypes - Internal functions
 */
/* Attach detach */
static int      ath5k_attach(struct net80211_device *dev);
static void     ath5k_detach(struct net80211_device *dev);
/* Channel/mode setup */
static unsigned int ath5k_copy_channels(struct ath5k_hw *ah,
                                struct net80211_channel *channels,
                                unsigned int mode,
                                unsigned int max);
static int      ath5k_setup_bands(struct net80211_device *dev);
static int      ath5k_chan_set(struct ath5k_softc *sc,
                                struct net80211_channel *chan);
static void     ath5k_setcurmode(struct ath5k_softc *sc,
                                unsigned int mode);
static void     ath5k_mode_setup(struct ath5k_softc *sc);

/* Descriptor setup */
static int      ath5k_desc_alloc(struct ath5k_softc *sc);
static void     ath5k_desc_free(struct ath5k_softc *sc);
/* Buffers setup */
static int      ath5k_rxbuf_setup(struct ath5k_softc *sc, struct ath5k_buf *bf);
static int      ath5k_txbuf_setup(struct ath5k_softc *sc, struct ath5k_buf *bf);

static inline void ath5k_txbuf_free(struct ath5k_softc *sc,
                                    struct ath5k_buf *bf)
{
        if (!bf->iob)
                return;

        net80211_tx_complete(sc->dev, bf->iob, 0, ECANCELED);
        bf->iob = NULL;
}

static inline void ath5k_rxbuf_free(struct ath5k_softc *sc __unused,
                                    struct ath5k_buf *bf)
{
        free_iob(bf->iob);
        bf->iob = NULL;
}

/* Queues setup */
static int      ath5k_txq_setup(struct ath5k_softc *sc,
                                           int qtype, int subtype);
static void     ath5k_txq_drainq(struct ath5k_softc *sc,
                                 struct ath5k_txq *txq);
static void     ath5k_txq_cleanup(struct ath5k_softc *sc);
static void     ath5k_txq_release(struct ath5k_softc *sc);
/* Rx handling */
static int      ath5k_rx_start(struct ath5k_softc *sc);
static void     ath5k_rx_stop(struct ath5k_softc *sc);
/* Tx handling */
static void     ath5k_tx_processq(struct ath5k_softc *sc,
                                  struct ath5k_txq *txq);

/* Interrupt handling */
static int      ath5k_init(struct ath5k_softc *sc);
static int      ath5k_stop_hw(struct ath5k_softc *sc);

static void     ath5k_calibrate(struct ath5k_softc *sc);

/* Filter */
static void     ath5k_configure_filter(struct ath5k_softc *sc);

/********************\
* PCI Initialization *
\********************/

#if DBGLVL_MAX
static const char *
ath5k_chip_name(enum ath5k_srev_type type, u16 val)
{
        const char *name = "xxxxx";
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(srev_names); i++) {
                if (srev_names[i].sr_type != type)
                        continue;

                if ((val & 0xf0) == srev_names[i].sr_val)
                        name = srev_names[i].sr_name;

                if ((val & 0xff) == srev_names[i].sr_val) {
                        name = srev_names[i].sr_name;
                        break;
                }
        }

        return name;
}
#endif

static int ath5k_probe(struct pci_device *pdev)
{
        void *mem;
        struct ath5k_softc *sc;
        struct net80211_device *dev;
        int ret;
        u8 csz;

        adjust_pci_device(pdev);

        /*
         * Cache line size is used to size and align various
         * structures used to communicate with the hardware.
         */
        pci_read_config_byte(pdev, PCI_CACHE_LINE_SIZE, &csz);
        if (csz == 0) {
                /*
                 * We must have this setup properly for rx buffer
                 * DMA to work so force a reasonable value here if it
                 * comes up zero.
                 */
                csz = 16;
                pci_write_config_byte(pdev, PCI_CACHE_LINE_SIZE, csz);
        }
        /*
         * The default setting of latency timer yields poor results,
         * set it to the value used by other systems.  It may be worth
         * tweaking this setting more.
         */
        pci_write_config_byte(pdev, PCI_LATENCY_TIMER, 0xa8);

        /*
         * Disable the RETRY_TIMEOUT register (0x41) to keep
         * PCI Tx retries from interfering with C3 CPU state.
         */
        pci_write_config_byte(pdev, 0x41, 0);

        mem = pci_ioremap(pdev, pdev->membase, 0x10000);
        if (!mem) {
                DBG("ath5k: cannot remap PCI memory region\n");
                ret = -EIO;
                goto err;
        }

        /*
         * Allocate dev (net80211 main struct)
         * and dev->priv (driver private data)
         */
        dev = net80211_alloc(sizeof(*sc));
        if (!dev) {
                DBG("ath5k: cannot allocate 802.11 device\n");
                ret = -ENOMEM;
                goto err_map;
        }

        /* Initialize driver private data */
        sc = dev->priv;
        sc->dev = dev;
        sc->pdev = pdev;

        sc->hwinfo = zalloc(sizeof(*sc->hwinfo));
        if (!sc->hwinfo) {
                DBG("ath5k: cannot allocate 802.11 hardware info structure\n");
                ret = -ENOMEM;
                goto err_free;
        }

        sc->hwinfo->flags = NET80211_HW_RX_HAS_FCS;
        sc->hwinfo->signal_type = NET80211_SIGNAL_DB;
        sc->hwinfo->signal_max = 40; /* 35dB should give perfect 54Mbps */
        sc->hwinfo->channel_change_time = 5000;

        /* Avoid working with the device until setup is complete */
        sc->status |= ATH_STAT_INVALID;

        sc->iobase = mem;
        sc->cachelsz = csz * 4; /* convert to bytes */

        DBG("ath5k: register base at %p (%08lx)\n", sc->iobase, pdev->membase);
        DBG("ath5k: cache line size %d\n", sc->cachelsz);

        /* Set private data */
        pci_set_drvdata(pdev, dev);
        dev->netdev->dev = (struct device *)pdev;

        /* Initialize device */
        ret = ath5k_hw_attach(sc, pdev->id->driver_data, &sc->ah);
        if (ret)
                goto err_free_hwinfo;

        /* Finish private driver data initialization */
        ret = ath5k_attach(dev);
        if (ret)
                goto err_ah;

#if DBGLVL_MAX
        DBG("Atheros AR%s chip found (MAC: 0x%x, PHY: 0x%x)\n",
            ath5k_chip_name(AR5K_VERSION_MAC, sc->ah->ah_mac_srev),
            sc->ah->ah_mac_srev, sc->ah->ah_phy_revision);

        if (!sc->ah->ah_single_chip) {
                /* Single chip radio (!RF5111) */
                if (sc->ah->ah_radio_5ghz_revision &&
                    !sc->ah->ah_radio_2ghz_revision) {
                        /* No 5GHz support -> report 2GHz radio */
                        if (!(sc->ah->ah_capabilities.cap_mode & AR5K_MODE_BIT_11A)) {
                                DBG("RF%s 2GHz radio found (0x%x)\n",
                                    ath5k_chip_name(AR5K_VERSION_RAD,
                                                    sc->ah->ah_radio_5ghz_revision),
                                    sc->ah->ah_radio_5ghz_revision);
                        /* No 2GHz support (5110 and some
                         * 5Ghz only cards) -> report 5Ghz radio */
                        } else if (!(sc->ah->ah_capabilities.cap_mode & AR5K_MODE_BIT_11B)) {
                                DBG("RF%s 5GHz radio found (0x%x)\n",
                                    ath5k_chip_name(AR5K_VERSION_RAD,
                                                    sc->ah->ah_radio_5ghz_revision),
                                    sc->ah->ah_radio_5ghz_revision);
                        /* Multiband radio */
                        } else {
                                DBG("RF%s multiband radio found (0x%x)\n",
                                    ath5k_chip_name(AR5K_VERSION_RAD,
                                                    sc->ah->ah_radio_5ghz_revision),
                                    sc->ah->ah_radio_5ghz_revision);
                        }
                }
                /* Multi chip radio (RF5111 - RF2111) ->
                 * report both 2GHz/5GHz radios */
                else if (sc->ah->ah_radio_5ghz_revision &&
                         sc->ah->ah_radio_2ghz_revision) {
                        DBG("RF%s 5GHz radio found (0x%x)\n",
                            ath5k_chip_name(AR5K_VERSION_RAD,
                                            sc->ah->ah_radio_5ghz_revision),
                            sc->ah->ah_radio_5ghz_revision);
                        DBG("RF%s 2GHz radio found (0x%x)\n",
                            ath5k_chip_name(AR5K_VERSION_RAD,
                                            sc->ah->ah_radio_2ghz_revision),
                            sc->ah->ah_radio_2ghz_revision);
                }
        }
#endif

        /* Ready to go */
        sc->status &= ~ATH_STAT_INVALID;

        return 0;
err_ah:
        ath5k_hw_detach(sc->ah);
err_free_hwinfo:
        free(sc->hwinfo);
err_free:
        net80211_free(dev);
err_map:
        iounmap(mem);
err:
        return ret;
}

static void ath5k_remove(struct pci_device *pdev)
{
        struct net80211_device *dev = pci_get_drvdata(pdev);
        struct ath5k_softc *sc = dev->priv;

        ath5k_detach(dev);
        ath5k_hw_detach(sc->ah);
        iounmap(sc->iobase);
        free(sc->hwinfo);
        net80211_free(dev);
}


/***********************\
* Driver Initialization *
\***********************/

static int
ath5k_attach(struct net80211_device *dev)
{
        struct ath5k_softc *sc = dev->priv;
        struct ath5k_hw *ah = sc->ah;
        int ret;

        /*
         * Collect the channel list.  The 802.11 layer
         * is resposible for filtering this list based
         * on settings like the phy mode and regulatory
         * domain restrictions.
         */
        ret = ath5k_setup_bands(dev);
        if (ret) {
                DBG("ath5k: can't get channels\n");
                goto err;
        }

        /* NB: setup here so ath5k_rate_update is happy */
        if (ah->ah_modes & AR5K_MODE_BIT_11A)
                ath5k_setcurmode(sc, AR5K_MODE_11A);
        else
                ath5k_setcurmode(sc, AR5K_MODE_11B);

        /*
         * Allocate tx+rx descriptors and populate the lists.
         */
        ret = ath5k_desc_alloc(sc);
        if (ret) {
                DBG("ath5k: can't allocate descriptors\n");
                goto err;
        }

        /*
         * Allocate hardware transmit queues. Note that hw functions
         * handle reseting these queues at the needed time.
         */
        ret = ath5k_txq_setup(sc, AR5K_TX_QUEUE_DATA, AR5K_WME_AC_BE);
        if (ret) {
                DBG("ath5k: can't setup xmit queue\n");
                goto err_desc;
        }

        sc->last_calib_ticks = currticks();

        ret = ath5k_eeprom_read_mac(ah, sc->hwinfo->hwaddr);
        if (ret) {
                DBG("ath5k: unable to read address from EEPROM: 0x%04x\n",
                    sc->pdev->device);
                goto err_queues;
        }

        memset(sc->bssidmask, 0xff, ETH_ALEN);
        ath5k_hw_set_bssid_mask(sc->ah, sc->bssidmask);

        ret = net80211_register(sc->dev, &ath5k_ops, sc->hwinfo);
        if (ret) {
                DBG("ath5k: can't register ieee80211 hw\n");
                goto err_queues;
        }

        return 0;
err_queues:
        ath5k_txq_release(sc);
err_desc:
        ath5k_desc_free(sc);
err:
        return ret;
}

static void
ath5k_detach(struct net80211_device *dev)
{
        struct ath5k_softc *sc = dev->priv;

        net80211_unregister(dev);
        ath5k_desc_free(sc);
        ath5k_txq_release(sc);
}




/********************\
* Channel/mode setup *
\********************/

/*
 * Convert IEEE channel number to MHz frequency.
 */
static inline short
ath5k_ieee2mhz(short chan)
{
        if (chan < 14)
                return 2407 + 5 * chan;
        if (chan == 14)
                return 2484;
        if (chan < 27)
                return 2212 + 20 * chan;
        return 5000 + 5 * chan;
}

static unsigned int
ath5k_copy_channels(struct ath5k_hw *ah,
                    struct net80211_channel *channels,
                    unsigned int mode, unsigned int max)
{
        unsigned int i, count, size, chfreq, freq, ch;

        if (!(ah->ah_modes & (1 << mode)))
                return 0;

        switch (mode) {
        case AR5K_MODE_11A:
        case AR5K_MODE_11A_TURBO:
                /* 1..220, but 2GHz frequencies are filtered by check_channel */
                size = 220;
                chfreq = CHANNEL_5GHZ;
                break;
        case AR5K_MODE_11B:
        case AR5K_MODE_11G:
        case AR5K_MODE_11G_TURBO:
                size = 26;
                chfreq = CHANNEL_2GHZ;
                break;
        default:
                return 0;
        }

        for (i = 0, count = 0; i < size && max > 0; i++) {
                ch = i + 1 ;
                freq = ath5k_ieee2mhz(ch);

                /* Check if channel is supported by the chipset */
                if (!ath5k_channel_ok(ah, freq, chfreq))
                        continue;

                /* Write channel info and increment counter */
                channels[count].center_freq = freq;
                channels[count].maxpower = 0; /* use regulatory */
                channels[count].band = (chfreq == CHANNEL_2GHZ) ?
                        NET80211_BAND_2GHZ : NET80211_BAND_5GHZ;
                switch (mode) {
                case AR5K_MODE_11A:
                case AR5K_MODE_11G:
                        channels[count].hw_value = chfreq | CHANNEL_OFDM;
                        break;
                case AR5K_MODE_11A_TURBO:
                case AR5K_MODE_11G_TURBO:
                        channels[count].hw_value = chfreq |
                                CHANNEL_OFDM | CHANNEL_TURBO;
                        break;
                case AR5K_MODE_11B:
                        channels[count].hw_value = CHANNEL_B;
                }

                count++;
                max--;
        }

        return count;
}

static int
ath5k_setup_bands(struct net80211_device *dev)
{
        struct ath5k_softc *sc = dev->priv;
        struct ath5k_hw *ah = sc->ah;
        int max_c, count_c = 0;
        int i;
        int band;

        max_c = sizeof(sc->hwinfo->channels) / sizeof(sc->hwinfo->channels[0]);

        /* 2GHz band */
        if (sc->ah->ah_capabilities.cap_mode & AR5K_MODE_BIT_11G) {
                /* G mode */
                band = NET80211_BAND_2GHZ;
                sc->hwinfo->bands = NET80211_BAND_BIT_2GHZ;
                sc->hwinfo->modes = (NET80211_MODE_G | NET80211_MODE_B);

                for (i = 0; i < 12; i++)
                        sc->hwinfo->rates[band][i] = ath5k_rates[i].bitrate;
                sc->hwinfo->nr_rates[band] = 12;

                sc->hwinfo->nr_channels =
                        ath5k_copy_channels(ah, sc->hwinfo->channels,
                                            AR5K_MODE_11G, max_c);
                count_c = sc->hwinfo->nr_channels;
                max_c -= count_c;
        } else if (sc->ah->ah_capabilities.cap_mode & AR5K_MODE_BIT_11B) {
                /* B mode */
                band = NET80211_BAND_2GHZ;
                sc->hwinfo->bands = NET80211_BAND_BIT_2GHZ;
                sc->hwinfo->modes = NET80211_MODE_B;

                for (i = 0; i < 4; i++)
                        sc->hwinfo->rates[band][i] = ath5k_rates[i].bitrate;
                sc->hwinfo->nr_rates[band] = 4;

                sc->hwinfo->nr_channels =
                        ath5k_copy_channels(ah, sc->hwinfo->channels,
                                            AR5K_MODE_11B, max_c);
                count_c = sc->hwinfo->nr_channels;
                max_c -= count_c;
        }

        /* 5GHz band, A mode */
        if (sc->ah->ah_capabilities.cap_mode & AR5K_MODE_BIT_11A) {
                band = NET80211_BAND_5GHZ;
                sc->hwinfo->bands |= NET80211_BAND_BIT_5GHZ;
                sc->hwinfo->modes |= NET80211_MODE_A;

                for (i = 0; i < 8; i++)
                        sc->hwinfo->rates[band][i] = ath5k_rates[i+4].bitrate;
                sc->hwinfo->nr_rates[band] = 8;

                sc->hwinfo->nr_channels =
                        ath5k_copy_channels(ah, sc->hwinfo->channels,
                                            AR5K_MODE_11B, max_c);
                count_c = sc->hwinfo->nr_channels;
                max_c -= count_c;
        }

        return 0;
}

/*
 * Set/change channels.  If the channel is really being changed,
 * it's done by reseting the chip.  To accomplish this we must
 * first cleanup any pending DMA, then restart stuff after a la
 * ath5k_init.
 */
static int
ath5k_chan_set(struct ath5k_softc *sc, struct net80211_channel *chan)
{
        if (chan->center_freq != sc->curchan->center_freq ||
            chan->hw_value != sc->curchan->hw_value) {
                /*
                 * To switch channels clear any pending DMA operations;
                 * wait long enough for the RX fifo to drain, reset the
                 * hardware at the new frequency, and then re-enable
                 * the relevant bits of the h/w.
                 */
                DBG2("ath5k: resetting for channel change (%d -> %d MHz)\n",
                     sc->curchan->center_freq, chan->center_freq);
                return ath5k_reset(sc, chan);
        }

        return 0;
}

static void
ath5k_setcurmode(struct ath5k_softc *sc, unsigned int mode)
{
        sc->curmode = mode;

        if (mode == AR5K_MODE_11A) {
                sc->curband = NET80211_BAND_5GHZ;
        } else {
                sc->curband = NET80211_BAND_2GHZ;
        }
}

static void
ath5k_mode_setup(struct ath5k_softc *sc)
{
        struct ath5k_hw *ah = sc->ah;
        u32 rfilt;

        /* configure rx filter */
        rfilt = sc->filter_flags;
        ath5k_hw_set_rx_filter(ah, rfilt);

        if (ath5k_hw_hasbssidmask(ah))
                ath5k_hw_set_bssid_mask(ah, sc->bssidmask);

        /* configure operational mode */
        ath5k_hw_set_opmode(ah);

        ath5k_hw_set_mcast_filter(ah, 0, 0);
}

static inline int
ath5k_hw_rix_to_bitrate(int hw_rix)
{
        int i;

        for (i = 0; i < ATH5K_NR_RATES; i++) {
                if (ath5k_rates[i].hw_code == hw_rix)
                        return ath5k_rates[i].bitrate;
        }

        DBG("ath5k: invalid rix %02x\n", hw_rix);
        return 10;              /* use lowest rate */
}

int ath5k_bitrate_to_hw_rix(int bitrate)
{
        int i;

        for (i = 0; i < ATH5K_NR_RATES; i++) {
                if (ath5k_rates[i].bitrate == bitrate)
                        return ath5k_rates[i].hw_code;
        }

        DBG("ath5k: invalid bitrate %d\n", bitrate);
        return ATH5K_RATE_CODE_1M; /* use lowest rate */
}

/***************\
* Buffers setup *
\***************/

static struct io_buffer *
ath5k_rx_iob_alloc(struct ath5k_softc *sc, u32 *iob_addr)
{
        struct io_buffer *iob;
        unsigned int off;

        /*
         * Allocate buffer with headroom_needed space for the
         * fake physical layer header at the start.
         */
        iob = alloc_iob(sc->rxbufsize + sc->cachelsz - 1);

        if (!iob) {
                DBG("ath5k: can't alloc iobuf of size %d\n",
                    sc->rxbufsize + sc->cachelsz - 1);
                return NULL;
        }

        *iob_addr = virt_to_bus(iob->data);

        /*
         * Cache-line-align.  This is important (for the
         * 5210 at least) as not doing so causes bogus data
         * in rx'd frames.
         */
        off = *iob_addr % sc->cachelsz;
        if (off != 0) {
                iob_reserve(iob, sc->cachelsz - off);
                *iob_addr += sc->cachelsz - off;
        }

        return iob;
}

static int
ath5k_rxbuf_setup(struct ath5k_softc *sc, struct ath5k_buf *bf)
{
        struct ath5k_hw *ah = sc->ah;
        struct io_buffer *iob = bf->iob;
        struct ath5k_desc *ds;

        if (!iob) {
                iob = ath5k_rx_iob_alloc(sc, &bf->iobaddr);
                if (!iob)
                        return -ENOMEM;
                bf->iob = iob;
        }

        /*
         * Setup descriptors.  For receive we always terminate
         * the descriptor list with a self-linked entry so we'll
         * not get overrun under high load (as can happen with a
         * 5212 when ANI processing enables PHY error frames).
         *
         * To insure the last descriptor is self-linked we create
         * each descriptor as self-linked and add it to the end.  As
         * each additional descriptor is added the previous self-linked
         * entry is ``fixed'' naturally.  This should be safe even
         * if DMA is happening.  When processing RX interrupts we
         * never remove/process the last, self-linked, entry on the
         * descriptor list.  This insures the hardware always has
         * someplace to write a new frame.
         */
        ds = bf->desc;
        ds->ds_link = bf->daddr;        /* link to self */
        ds->ds_data = bf->iobaddr;
        if (ah->ah_setup_rx_desc(ah, ds,
                                 iob_tailroom(iob),     /* buffer size */
                                 0) != 0) {
                DBG("ath5k: error setting up RX descriptor for %zd bytes\n", iob_tailroom(iob));
                return -EINVAL;
        }

        if (sc->rxlink != NULL)
                *sc->rxlink = bf->daddr;
        sc->rxlink = &ds->ds_link;
        return 0;
}

static int
ath5k_txbuf_setup(struct ath5k_softc *sc, struct ath5k_buf *bf)
{
        struct ath5k_hw *ah = sc->ah;
        struct ath5k_txq *txq = &sc->txq;
        struct ath5k_desc *ds = bf->desc;
        struct io_buffer *iob = bf->iob;
        unsigned int pktlen, flags;
        int ret;
        u16 duration = 0;
        u16 cts_rate = 0;

        flags = AR5K_TXDESC_INTREQ | AR5K_TXDESC_CLRDMASK;
        bf->iobaddr = virt_to_bus(iob->data);
        pktlen = iob_len(iob);

        /* FIXME: If we are in g mode and rate is a CCK rate
         * subtract ah->ah_txpower.txp_cck_ofdm_pwr_delta
         * from tx power (value is in dB units already) */
        if (sc->dev->phy_flags & NET80211_PHY_USE_PROTECTION) {
                struct net80211_device *dev = sc->dev;

                flags |= AR5K_TXDESC_CTSENA;
                cts_rate = sc->hw_rtscts_rate;
                duration = net80211_cts_duration(dev, pktlen);
        }
        ret = ah->ah_setup_tx_desc(ah, ds, pktlen,
                                   IEEE80211_TYP_FRAME_HEADER_LEN,
                                   AR5K_PKT_TYPE_NORMAL, sc->power_level * 2,
                                   sc->hw_rate, ATH5K_RETRIES,
                                   AR5K_TXKEYIX_INVALID, 0, flags,
                                   cts_rate, duration);
        if (ret)
                return ret;

        ds->ds_link = 0;
        ds->ds_data = bf->iobaddr;

        list_add_tail(&bf->list, &txq->q);
        if (txq->link == NULL) /* is this first packet? */
                ath5k_hw_set_txdp(ah, txq->qnum, bf->daddr);
        else /* no, so only link it */
                *txq->link = bf->daddr;

        txq->link = &ds->ds_link;
        ath5k_hw_start_tx_dma(ah, txq->qnum);
        mb();

        return 0;
}

/*******************\
* Descriptors setup *
\*******************/

static int
ath5k_desc_alloc(struct ath5k_softc *sc)
{
        struct ath5k_desc *ds;
        struct ath5k_buf *bf;
        u32 da;
        unsigned int i;
        int ret;

        /* allocate descriptors */
        sc->desc_len = sizeof(struct ath5k_desc) * (ATH_TXBUF + ATH_RXBUF + 1);
        sc->desc = malloc_phys(sc->desc_len, ATH5K_DESC_ALIGN);
        if (sc->desc == NULL) {
                DBG("ath5k: can't allocate descriptors\n");
                ret = -ENOMEM;
                goto err;
        }
        memset(sc->desc, 0, sc->desc_len);
        sc->desc_daddr = virt_to_bus(sc->desc);

        ds = sc->desc;
        da = sc->desc_daddr;

        bf = calloc(ATH_TXBUF + ATH_RXBUF + 1, sizeof(struct ath5k_buf));
        if (bf == NULL) {
                DBG("ath5k: can't allocate buffer pointers\n");
                ret = -ENOMEM;
                goto err_free;
        }
        sc->bufptr = bf;

        INIT_LIST_HEAD(&sc->rxbuf);
        for (i = 0; i < ATH_RXBUF; i++, bf++, ds++, da += sizeof(*ds)) {
                bf->desc = ds;
                bf->daddr = da;
                list_add_tail(&bf->list, &sc->rxbuf);
        }

        INIT_LIST_HEAD(&sc->txbuf);
        sc->txbuf_len = ATH_TXBUF;
        for (i = 0; i < ATH_TXBUF; i++, bf++, ds++, da += sizeof(*ds)) {
                bf->desc = ds;
                bf->daddr = da;
                list_add_tail(&bf->list, &sc->txbuf);
        }

        return 0;

err_free:
        free_phys(sc->desc, sc->desc_len);
err:
        sc->desc = NULL;
        return ret;
}

static void
ath5k_desc_free(struct ath5k_softc *sc)
{
        struct ath5k_buf *bf;

        list_for_each_entry(bf, &sc->txbuf, list)
                ath5k_txbuf_free(sc, bf);
        list_for_each_entry(bf, &sc->rxbuf, list)
                ath5k_rxbuf_free(sc, bf);

        /* Free memory associated with all descriptors */
        free_phys(sc->desc, sc->desc_len);

        free(sc->bufptr);
        sc->bufptr = NULL;
}





/**************\
* Queues setup *
\**************/

static int
ath5k_txq_setup(struct ath5k_softc *sc, int qtype, int subtype)
{
        struct ath5k_hw *ah = sc->ah;
        struct ath5k_txq *txq;
        struct ath5k_txq_info qi = {
                .tqi_subtype = subtype,
                .tqi_aifs = AR5K_TXQ_USEDEFAULT,
                .tqi_cw_min = AR5K_TXQ_USEDEFAULT,
                .tqi_cw_max = AR5K_TXQ_USEDEFAULT
        };
        int qnum;

        /*
         * Enable interrupts only for EOL and DESC conditions.
         * We mark tx descriptors to receive a DESC interrupt
         * when a tx queue gets deep; otherwise waiting for the
         * EOL to reap descriptors.  Note that this is done to
         * reduce interrupt load and this only defers reaping
         * descriptors, never transmitting frames.  Aside from
         * reducing interrupts this also permits more concurrency.
         * The only potential downside is if the tx queue backs
         * up in which case the top half of the kernel may backup
         * due to a lack of tx descriptors.
         */
        qi.tqi_flags = AR5K_TXQ_FLAG_TXEOLINT_ENABLE |
                                AR5K_TXQ_FLAG_TXDESCINT_ENABLE;
        qnum = ath5k_hw_setup_tx_queue(ah, qtype, &qi);
        if (qnum < 0) {
                DBG("ath5k: can't set up a TX queue\n");
                return -EIO;
        }

        txq = &sc->txq;
        if (!txq->setup) {
                txq->qnum = qnum;
                txq->link = NULL;
                INIT_LIST_HEAD(&txq->q);
                txq->setup = 1;
        }
        return 0;
}

static void
ath5k_txq_drainq(struct ath5k_softc *sc, struct ath5k_txq *txq)
{
        struct ath5k_buf *bf, *bf0;

        list_for_each_entry_safe(bf, bf0, &txq->q, list) {
                ath5k_txbuf_free(sc, bf);

                list_del(&bf->list);
                list_add_tail(&bf->list, &sc->txbuf);
                sc->txbuf_len++;
        }
        txq->link = NULL;
}

/*
 * Drain the transmit queues and reclaim resources.
 */
static void
ath5k_txq_cleanup(struct ath5k_softc *sc)
{
        struct ath5k_hw *ah = sc->ah;

        if (!(sc->status & ATH_STAT_INVALID)) {
                /* don't touch the hardware if marked invalid */
                if (sc->txq.setup) {
                        ath5k_hw_stop_tx_dma(ah, sc->txq.qnum);
                        DBG("ath5k: txq [%d] %x, link %p\n",
                            sc->txq.qnum,
                            ath5k_hw_get_txdp(ah, sc->txq.qnum),
                            sc->txq.link);
                }
        }

        if (sc->txq.setup)
                ath5k_txq_drainq(sc, &sc->txq);
}

static void
ath5k_txq_release(struct ath5k_softc *sc)
{
        if (sc->txq.setup) {
                ath5k_hw_release_tx_queue(sc->ah);
                sc->txq.setup = 0;
        }
}




/*************\
* RX Handling *
\*************/

/*
 * Enable the receive h/w following a reset.
 */
static int
ath5k_rx_start(struct ath5k_softc *sc)
{
        struct ath5k_hw *ah = sc->ah;
        struct ath5k_buf *bf;
        int ret;

        sc->rxbufsize = IEEE80211_MAX_LEN;
        if (sc->rxbufsize % sc->cachelsz != 0)
                sc->rxbufsize += sc->cachelsz - (sc->rxbufsize % sc->cachelsz);

        sc->rxlink = NULL;

        list_for_each_entry(bf, &sc->rxbuf, list) {
                ret = ath5k_rxbuf_setup(sc, bf);
                if (ret != 0)
                        return ret;
        }

        bf = list_entry(sc->rxbuf.next, struct ath5k_buf, list);

        ath5k_hw_set_rxdp(ah, bf->daddr);
        ath5k_hw_start_rx_dma(ah);      /* enable recv descriptors */
        ath5k_mode_setup(sc);           /* set filters, etc. */
        ath5k_hw_start_rx_pcu(ah);      /* re-enable PCU/DMA engine */

        return 0;
}

/*
 * Disable the receive h/w in preparation for a reset.
 */
static void
ath5k_rx_stop(struct ath5k_softc *sc)
{
        struct ath5k_hw *ah = sc->ah;

        ath5k_hw_stop_rx_pcu(ah);       /* disable PCU */
        ath5k_hw_set_rx_filter(ah, 0);  /* clear recv filter */
        ath5k_hw_stop_rx_dma(ah);       /* disable DMA engine */

        sc->rxlink = NULL;              /* just in case */
}

static void
ath5k_handle_rx(struct ath5k_softc *sc)
{
        struct ath5k_rx_status rs;
        struct io_buffer *iob, *next_iob;
        u32 next_iob_addr;
        struct ath5k_buf *bf, *bf_last;
        struct ath5k_desc *ds;
        int ret;

        memset(&rs, 0, sizeof(rs));

        if (list_empty(&sc->rxbuf)) {
                DBG("ath5k: empty rx buf pool\n");
                return;
        }

        bf_last = list_entry(sc->rxbuf.prev, struct ath5k_buf, list);

        do {
                bf = list_entry(sc->rxbuf.next, struct ath5k_buf, list);
                assert(bf->iob != NULL);
                iob = bf->iob;
                ds = bf->desc;

                /*
                 * last buffer must not be freed to ensure proper hardware
                 * function. When the hardware finishes also a packet next to
                 * it, we are sure, it doesn't use it anymore and we can go on.
                 */
                if (bf_last == bf)
                        bf->flags |= 1;
                if (bf->flags) {
                        struct ath5k_buf *bf_next = list_entry(bf->list.next,
                                        struct ath5k_buf, list);
                        ret = sc->ah->ah_proc_rx_desc(sc->ah, bf_next->desc,
                                        &rs);
                        if (ret)
                                break;
                        bf->flags &= ~1;
                        /* skip the overwritten one (even status is martian) */
                        goto next;
                }

                ret = sc->ah->ah_proc_rx_desc(sc->ah, ds, &rs);
                if (ret) {
                        if (ret != -EINPROGRESS) {
                                DBG("ath5k: error in processing rx desc: %s\n",
                                    strerror(ret));
                                net80211_rx_err(sc->dev, NULL, -ret);
                        } else {
                                /* normal return, reached end of
                                   available descriptors */
                        }
                        return;
                }

                if (rs.rs_more) {
                        DBG("ath5k: unsupported fragmented rx\n");
                        goto next;
                }

                if (rs.rs_status) {
                        if (rs.rs_status & AR5K_RXERR_PHY) {
                                /* These are uncommon, and may indicate a real problem. */
                                net80211_rx_err(sc->dev, NULL, EIO);
                                goto next;
                        }
                        if (rs.rs_status & AR5K_RXERR_CRC) {
                                /* These occur *all the time*. */
                                goto next;
                        }
                        if (rs.rs_status & AR5K_RXERR_DECRYPT) {
                                /*
                                 * Decrypt error.  If the error occurred
                                 * because there was no hardware key, then
                                 * let the frame through so the upper layers
                                 * can process it.  This is necessary for 5210
                                 * parts which have no way to setup a ``clear''
                                 * key cache entry.
                                 *
                                 * XXX do key cache faulting
                                 */
                                if (rs.rs_keyix == AR5K_RXKEYIX_INVALID &&
                                    !(rs.rs_status & AR5K_RXERR_CRC))
                                        goto accept;
                        }

                        /* any other error, unhandled */
                        DBG("ath5k: packet rx status %x\n", rs.rs_status);
                        goto next;
                }
accept:
                next_iob = ath5k_rx_iob_alloc(sc, &next_iob_addr);

                /*
                 * If we can't replace bf->iob with a new iob under memory
                 * pressure, just skip this packet
                 */
                if (!next_iob) {
                        DBG("ath5k: dropping packet under memory pressure\n");
                        goto next;
                }

                iob_put(iob, rs.rs_datalen);

                /* The MAC header is padded to have 32-bit boundary if the
                 * packet payload is non-zero. However, iPXE only
                 * supports standard 802.11 packets with 24-byte
                 * header, so no padding correction should be needed.
                 */

                DBG2("ath5k: rx %d bytes, signal %d\n", rs.rs_datalen,
                     rs.rs_rssi);

                net80211_rx(sc->dev, iob, rs.rs_rssi,
                            ath5k_hw_rix_to_bitrate(rs.rs_rate));

                bf->iob = next_iob;
                bf->iobaddr = next_iob_addr;
next:
                list_del(&bf->list);
                list_add_tail(&bf->list, &sc->rxbuf);
        } while (ath5k_rxbuf_setup(sc, bf) == 0);
}




/*************\
* TX Handling *
\*************/

static void
ath5k_tx_processq(struct ath5k_softc *sc, struct ath5k_txq *txq)
{
        struct ath5k_tx_status ts;
        struct ath5k_buf *bf, *bf0;
        struct ath5k_desc *ds;
        struct io_buffer *iob;
        int ret;

        memset(&ts, 0, sizeof(ts));

        list_for_each_entry_safe(bf, bf0, &txq->q, list) {
                ds = bf->desc;

                ret = sc->ah->ah_proc_tx_desc(sc->ah, ds, &ts);
                if (ret) {
                        if (ret != -EINPROGRESS) {
                                DBG("ath5k: error in processing tx desc: %s\n",
                                    strerror(ret));
                        } else {
                                /* normal return, reached end of tx completions */
                        }
                        break;
                }

                iob = bf->iob;
                bf->iob = NULL;

                DBG2("ath5k: tx %zd bytes complete, %d retries\n",
                     iob_len(iob), ts.ts_retry[0]);

                net80211_tx_complete(sc->dev, iob, ts.ts_retry[0],
                                     ts.ts_status ? EIO : 0);

                list_del(&bf->list);
                list_add_tail(&bf->list, &sc->txbuf);
                sc->txbuf_len++;
        }

        if (list_empty(&txq->q))
                txq->link = NULL;
}

static void
ath5k_handle_tx(struct ath5k_softc *sc)
{
        ath5k_tx_processq(sc, &sc->txq);
}


/********************\
* Interrupt handling *
\********************/

static void
ath5k_irq(struct net80211_device *dev, int enable)
{
        struct ath5k_softc *sc = dev->priv;
        struct ath5k_hw *ah = sc->ah;

        sc->irq_ena = enable;
        ah->ah_ier = enable ? AR5K_IER_ENABLE : AR5K_IER_DISABLE;

        ath5k_hw_reg_write(ah, ah->ah_ier, AR5K_IER);
        ath5k_hw_set_imr(ah, sc->imask);
}

static int
ath5k_init(struct ath5k_softc *sc)
{
        struct ath5k_hw *ah = sc->ah;
        int ret, i;

        /*
         * Stop anything previously setup.  This is safe
         * no matter this is the first time through or not.
         */
        ath5k_stop_hw(sc);

        /*
         * The basic interface to setting the hardware in a good
         * state is ``reset''.  On return the hardware is known to
         * be powered up and with interrupts disabled.  This must
         * be followed by initialization of the appropriate bits
         * and then setup of the interrupt mask.
         */
        sc->curchan = sc->dev->channels + sc->dev->channel;
        sc->curband = sc->curchan->band;
        sc->imask = AR5K_INT_RXOK | AR5K_INT_RXERR | AR5K_INT_RXEOL |
                AR5K_INT_RXORN | AR5K_INT_TXDESC | AR5K_INT_TXEOL |
                AR5K_INT_FATAL | AR5K_INT_GLOBAL;
        ret = ath5k_reset(sc, NULL);
        if (ret)
                goto done;

        ath5k_rfkill_hw_start(ah);

        /*
         * Reset the key cache since some parts do not reset the
         * contents on initial power up or resume from suspend.
         */
        for (i = 0; i < AR5K_KEYTABLE_SIZE; i++)
                ath5k_hw_reset_key(ah, i);

        /* Set ack to be sent at low bit-rates */
        ath5k_hw_set_ack_bitrate_high(ah, 0);

        ret = 0;
done:
        mb();
        return ret;
}

static int
ath5k_stop_hw(struct ath5k_softc *sc)
{
        struct ath5k_hw *ah = sc->ah;

        /*
         * Shutdown the hardware and driver:
         *    stop output from above
         *    disable interrupts
         *    turn off timers
         *    turn off the radio
         *    clear transmit machinery
         *    clear receive machinery
         *    drain and release tx queues
         *    reclaim beacon resources
         *    power down hardware
         *
         * Note that some of this work is not possible if the
         * hardware is gone (invalid).
         */

        if (!(sc->status & ATH_STAT_INVALID)) {
                ath5k_hw_set_imr(ah, 0);
        }
        ath5k_txq_cleanup(sc);
        if (!(sc->status & ATH_STAT_INVALID)) {
                ath5k_rx_stop(sc);
                ath5k_hw_phy_disable(ah);
        } else
                sc->rxlink = NULL;

        ath5k_rfkill_hw_stop(sc->ah);

        return 0;
}

static void
ath5k_poll(struct net80211_device *dev)
{
        struct ath5k_softc *sc = dev->priv;
        struct ath5k_hw *ah = sc->ah;
        enum ath5k_int status;
        unsigned int counter = 1000;

        if (currticks() - sc->last_calib_ticks >
            ATH5K_CALIB_INTERVAL * TICKS_PER_SEC) {
                ath5k_calibrate(sc);
                sc->last_calib_ticks = currticks();
        }

        if ((sc->status & ATH_STAT_INVALID) ||
            (sc->irq_ena && !ath5k_hw_is_intr_pending(ah)))
                return;

        do {
                ath5k_hw_get_isr(ah, &status);          /* NB: clears IRQ too */
                DBGP("ath5k: status %#x/%#x\n", status, sc->imask);
                if (status & AR5K_INT_FATAL) {
                        /*
                         * Fatal errors are unrecoverable.
                         * Typically these are caused by DMA errors.
                         */
                        DBG("ath5k: fatal error, resetting\n");
                        ath5k_reset_wake(sc);
                } else if (status & AR5K_INT_RXORN) {
                        DBG("ath5k: rx overrun, resetting\n");
                        ath5k_reset_wake(sc);
                } else {
                        if (status & AR5K_INT_RXEOL) {
                                /*
                                 * NB: the hardware should re-read the link when
                                 *     RXE bit is written, but it doesn't work at
                                 *     least on older hardware revs.
                                 */
                                DBG("ath5k: rx EOL\n");
                                sc->rxlink = NULL;
                        }
                        if (status & AR5K_INT_TXURN) {
                                /* bump tx trigger level */
                                DBG("ath5k: tx underrun\n");
                                ath5k_hw_update_tx_triglevel(ah, 1);
                        }
                        if (status & (AR5K_INT_RXOK | AR5K_INT_RXERR))
                                ath5k_handle_rx(sc);
                        if (status & (AR5K_INT_TXOK | AR5K_INT_TXDESC
                                      | AR5K_INT_TXERR | AR5K_INT_TXEOL))
                                ath5k_handle_tx(sc);
                }
        } while (ath5k_hw_is_intr_pending(ah) && counter-- > 0);

        if (!counter)
                DBG("ath5k: too many interrupts, giving up for now\n");
}

/*
 * Periodically recalibrate the PHY to account
 * for temperature/environment changes.
 */
static void
ath5k_calibrate(struct ath5k_softc *sc)
{
        struct ath5k_hw *ah = sc->ah;

        if (ath5k_hw_gainf_calibrate(ah) == AR5K_RFGAIN_NEED_CHANGE) {
                /*
                 * Rfgain is out of bounds, reset the chip
                 * to load new gain values.
                 */
                DBG("ath5k: resetting for calibration\n");
                ath5k_reset_wake(sc);
        }
        if (ath5k_hw_phy_calibrate(ah, sc->curchan))
                DBG("ath5k: calibration of channel %d failed\n",
                    sc->curchan->channel_nr);
}


/********************\
* Net80211 functions *
\********************/

static int
ath5k_tx(struct net80211_device *dev, struct io_buffer *iob)
{
        struct ath5k_softc *sc = dev->priv;
        struct ath5k_buf *bf;
        int rc;

        /*
         * The hardware expects the header padded to 4 byte boundaries.
         * iPXE only ever sends 24-byte headers, so no action necessary.
         */

        if (list_empty(&sc->txbuf)) {
                DBG("ath5k: dropping packet because no tx bufs available\n");
                return -ENOBUFS;
        }

        bf = list_entry(sc->txbuf.next, struct ath5k_buf, list);
        list_del(&bf->list);
        sc->txbuf_len--;

        bf->iob = iob;

        if ((rc = ath5k_txbuf_setup(sc, bf)) != 0) {
                bf->iob = NULL;
                list_add_tail(&bf->list, &sc->txbuf);
                sc->txbuf_len++;
                return rc;
        }
        return 0;
}

/*
 * Reset the hardware.  If chan is not NULL, then also pause rx/tx
 * and change to the given channel.
 */
static int
ath5k_reset(struct ath5k_softc *sc, struct net80211_channel *chan)
{
        struct ath5k_hw *ah = sc->ah;
        int ret;

        if (chan) {
                ath5k_hw_set_imr(ah, 0);
                ath5k_txq_cleanup(sc);
                ath5k_rx_stop(sc);

                sc->curchan = chan;
                sc->curband = chan->band;
        }

        ret = ath5k_hw_reset(ah, sc->curchan, 1);
        if (ret) {
                DBG("ath5k: can't reset hardware: %s\n", strerror(ret));
                return ret;
        }

        ret = ath5k_rx_start(sc);
        if (ret) {
                DBG("ath5k: can't start rx logic: %s\n", strerror(ret));
                return ret;
        }

        /*
         * Change channels and update the h/w rate map if we're switching;
         * e.g. 11a to 11b/g.
         *
         * We may be doing a reset in response to an ioctl that changes the
         * channel so update any state that might change as a result.
         *
         * XXX needed?
         */
/*      ath5k_chan_change(sc, c); */

        /* Reenable interrupts if necessary */
        ath5k_irq(sc->dev, sc->irq_ena);

        return 0;
}

static int ath5k_reset_wake(struct ath5k_softc *sc)
{
        return ath5k_reset(sc, sc->curchan);
}

static int ath5k_start(struct net80211_device *dev)
{
        struct ath5k_softc *sc = dev->priv;
        int ret;

        if ((ret = ath5k_init(sc)) != 0)
                return ret;

        sc->assoc = 0;
        ath5k_configure_filter(sc);
        ath5k_hw_set_lladdr(sc->ah, dev->netdev->ll_addr);

        return 0;
}

static void ath5k_stop(struct net80211_device *dev)
{
        struct ath5k_softc *sc = dev->priv;
        u8 mac[ETH_ALEN] = {};

        ath5k_hw_set_lladdr(sc->ah, mac);

        ath5k_stop_hw(sc);
}

static int
ath5k_config(struct net80211_device *dev, int changed)
{
        struct ath5k_softc *sc = dev->priv;
        struct ath5k_hw *ah = sc->ah;
        struct net80211_channel *chan = &dev->channels[dev->channel];
        int ret;

        if (changed & NET80211_CFG_CHANNEL) {
                sc->power_level = chan->maxpower;
                if ((ret = ath5k_chan_set(sc, chan)) != 0)
                        return ret;
        }

        if ((changed & NET80211_CFG_RATE) ||
            (changed & NET80211_CFG_PHY_PARAMS)) {
                int spmbl = ATH5K_SPMBL_NO;
                u16 rate = dev->rates[dev->rate];
                u16 slowrate = dev->rates[dev->rtscts_rate];
                int i;

                if (dev->phy_flags & NET80211_PHY_USE_SHORT_PREAMBLE)
                        spmbl = ATH5K_SPMBL_YES;

                for (i = 0; i < ATH5K_NR_RATES; i++) {
                        if (ath5k_rates[i].bitrate == rate &&
                            (ath5k_rates[i].short_pmbl & spmbl))
                                sc->hw_rate = ath5k_rates[i].hw_code;

                        if (ath5k_rates[i].bitrate == slowrate &&
                            (ath5k_rates[i].short_pmbl & spmbl))
                                sc->hw_rtscts_rate = ath5k_rates[i].hw_code;
                }
        }

        if (changed & NET80211_CFG_ASSOC) {
                sc->assoc = !!(dev->state & NET80211_ASSOCIATED);
                if (sc->assoc) {
                        memcpy(ah->ah_bssid, dev->bssid, ETH_ALEN);
                } else {
                        memset(ah->ah_bssid, 0xff, ETH_ALEN);
                }
                ath5k_hw_set_associd(ah, ah->ah_bssid, 0);
        }

        return 0;
}

/*
 * o always accept unicast, broadcast, and multicast traffic
 * o multicast traffic for all BSSIDs will be enabled if mac80211
 *   says it should be
 * o maintain current state of phy ofdm or phy cck error reception.
 *   If the hardware detects any of these type of errors then
 *   ath5k_hw_get_rx_filter() will pass to us the respective
 *   hardware filters to be able to receive these type of frames.
 * o probe request frames are accepted only when operating in
 *   hostap, adhoc, or monitor modes
 * o enable promiscuous mode according to the interface state
 * o accept beacons:
 *   - when operating in adhoc mode so the 802.11 layer creates
 *     node table entries for peers,
 *   - when operating in station mode for collecting rssi data when
 *     the station is otherwise quiet, or
 *   - when scanning
 */
static void ath5k_configure_filter(struct ath5k_softc *sc)
{
        struct ath5k_hw *ah = sc->ah;
        u32 mfilt[2], rfilt;

        /* Enable all multicast */
        mfilt[0] = ~0;
        mfilt[1] = ~0;

        /* Enable data frames and beacons */
        rfilt = (AR5K_RX_FILTER_UCAST | AR5K_RX_FILTER_BCAST |
                 AR5K_RX_FILTER_MCAST | AR5K_RX_FILTER_BEACON);

        /* Set filters */
        ath5k_hw_set_rx_filter(ah, rfilt);

        /* Set multicast bits */
        ath5k_hw_set_mcast_filter(ah, mfilt[0], mfilt[1]);

        /* Set the cached hw filter flags, this will alter actually
         * be set in HW */
        sc->filter_flags = rfilt;
}