spi-topcliff-pch: add recovery processing in case wait-event timeout

[zen-stable.git] / drivers / net / wireless / ath / ath5k / base.c

/*-
 * 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>
 *
 * 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.
 *
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/hardirq.h>
#include <linux/if.h>
#include <linux/io.h>
#include <linux/netdevice.h>
#include <linux/cache.h>
#include <linux/ethtool.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/etherdevice.h>
#include <linux/nl80211.h>

#include <net/ieee80211_radiotap.h>

#include <asm/unaligned.h>

#include "base.h"
#include "reg.h"
#include "debug.h"
#include "ani.h"
#include "ath5k.h"
#include "../regd.h"

#define CREATE_TRACE_POINTS
#include "trace.h"

bool ath5k_modparam_nohwcrypt;
module_param_named(nohwcrypt, ath5k_modparam_nohwcrypt, bool, S_IRUGO);
MODULE_PARM_DESC(nohwcrypt, "Disable hardware encryption.");

static bool modparam_all_channels;
module_param_named(all_channels, modparam_all_channels, bool, S_IRUGO);
MODULE_PARM_DESC(all_channels, "Expose all channels the device can use.");

static bool modparam_fastchanswitch;
module_param_named(fastchanswitch, modparam_fastchanswitch, bool, S_IRUGO);
MODULE_PARM_DESC(fastchanswitch, "Enable fast channel switching for AR2413/AR5413 radios.");

static int ath5k_modparam_no_hw_rfkill_switch;
module_param_named(no_hw_rfkill_switch, ath5k_modparam_no_hw_rfkill_switch,
                                                                bool, S_IRUGO);
MODULE_PARM_DESC(no_hw_rfkill_switch, "Ignore the GPIO RFKill switch state");


/* Module info */
MODULE_AUTHOR("Jiri Slaby");
MODULE_AUTHOR("Nick Kossifidis");
MODULE_DESCRIPTION("Support for 5xxx series of Atheros 802.11 wireless LAN cards.");
MODULE_SUPPORTED_DEVICE("Atheros 5xxx WLAN cards");
MODULE_LICENSE("Dual BSD/GPL");

static int ath5k_init(struct ieee80211_hw *hw);
static int ath5k_reset(struct ath5k_hw *ah, struct ieee80211_channel *chan,
                                                                bool skip_pcu);

/* Known SREVs */
static const struct ath5k_srev_name srev_names[] = {
#ifdef CONFIG_ATHEROS_AR231X
        { "5312",       AR5K_VERSION_MAC,       AR5K_SREV_AR5312_R2 },
        { "5312",       AR5K_VERSION_MAC,       AR5K_SREV_AR5312_R7 },
        { "2313",       AR5K_VERSION_MAC,       AR5K_SREV_AR2313_R8 },
        { "2315",       AR5K_VERSION_MAC,       AR5K_SREV_AR2315_R6 },
        { "2315",       AR5K_VERSION_MAC,       AR5K_SREV_AR2315_R7 },
        { "2317",       AR5K_VERSION_MAC,       AR5K_SREV_AR2317_R1 },
        { "2317",       AR5K_VERSION_MAC,       AR5K_SREV_AR2317_R2 },
#else
        { "5210",       AR5K_VERSION_MAC,       AR5K_SREV_AR5210 },
        { "5311",       AR5K_VERSION_MAC,       AR5K_SREV_AR5311 },
        { "5311A",      AR5K_VERSION_MAC,       AR5K_SREV_AR5311A },
        { "5311B",      AR5K_VERSION_MAC,       AR5K_SREV_AR5311B },
        { "5211",       AR5K_VERSION_MAC,       AR5K_SREV_AR5211 },
        { "5212",       AR5K_VERSION_MAC,       AR5K_SREV_AR5212 },
        { "5213",       AR5K_VERSION_MAC,       AR5K_SREV_AR5213 },
        { "5213A",      AR5K_VERSION_MAC,       AR5K_SREV_AR5213A },
        { "2413",       AR5K_VERSION_MAC,       AR5K_SREV_AR2413 },
        { "2414",       AR5K_VERSION_MAC,       AR5K_SREV_AR2414 },
        { "5424",       AR5K_VERSION_MAC,       AR5K_SREV_AR5424 },
        { "5413",       AR5K_VERSION_MAC,       AR5K_SREV_AR5413 },
        { "5414",       AR5K_VERSION_MAC,       AR5K_SREV_AR5414 },
        { "2415",       AR5K_VERSION_MAC,       AR5K_SREV_AR2415 },
        { "5416",       AR5K_VERSION_MAC,       AR5K_SREV_AR5416 },
        { "5418",       AR5K_VERSION_MAC,       AR5K_SREV_AR5418 },
        { "2425",       AR5K_VERSION_MAC,       AR5K_SREV_AR2425 },
        { "2417",       AR5K_VERSION_MAC,       AR5K_SREV_AR2417 },
#endif
        { "xxxxx",      AR5K_VERSION_MAC,       AR5K_SREV_UNKNOWN },
        { "5110",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_5110 },
        { "5111",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_5111 },
        { "5111A",      AR5K_VERSION_RAD,       AR5K_SREV_RAD_5111A },
        { "2111",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_2111 },
        { "5112",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_5112 },
        { "5112A",      AR5K_VERSION_RAD,       AR5K_SREV_RAD_5112A },
        { "5112B",      AR5K_VERSION_RAD,       AR5K_SREV_RAD_5112B },
        { "2112",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_2112 },
        { "2112A",      AR5K_VERSION_RAD,       AR5K_SREV_RAD_2112A },
        { "2112B",      AR5K_VERSION_RAD,       AR5K_SREV_RAD_2112B },
        { "2413",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_2413 },
        { "5413",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_5413 },
        { "5424",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_5424 },
        { "5133",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_5133 },
#ifdef CONFIG_ATHEROS_AR231X
        { "2316",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_2316 },
        { "2317",       AR5K_VERSION_RAD,       AR5K_SREV_RAD_2317 },
#endif
        { "xxxxx",      AR5K_VERSION_RAD,       AR5K_SREV_UNKNOWN },
};

static const struct ieee80211_rate ath5k_rates[] = {
        { .bitrate = 10,
          .hw_value = ATH5K_RATE_CODE_1M, },
        { .bitrate = 20,
          .hw_value = ATH5K_RATE_CODE_2M,
          .hw_value_short = ATH5K_RATE_CODE_2M | AR5K_SET_SHORT_PREAMBLE,
          .flags = IEEE80211_RATE_SHORT_PREAMBLE },
        { .bitrate = 55,
          .hw_value = ATH5K_RATE_CODE_5_5M,
          .hw_value_short = ATH5K_RATE_CODE_5_5M | AR5K_SET_SHORT_PREAMBLE,
          .flags = IEEE80211_RATE_SHORT_PREAMBLE },
        { .bitrate = 110,
          .hw_value = ATH5K_RATE_CODE_11M,
          .hw_value_short = ATH5K_RATE_CODE_11M | AR5K_SET_SHORT_PREAMBLE,
          .flags = IEEE80211_RATE_SHORT_PREAMBLE },
        { .bitrate = 60,
          .hw_value = ATH5K_RATE_CODE_6M,
          .flags = 0 },
        { .bitrate = 90,
          .hw_value = ATH5K_RATE_CODE_9M,
          .flags = 0 },
        { .bitrate = 120,
          .hw_value = ATH5K_RATE_CODE_12M,
          .flags = 0 },
        { .bitrate = 180,
          .hw_value = ATH5K_RATE_CODE_18M,
          .flags = 0 },
        { .bitrate = 240,
          .hw_value = ATH5K_RATE_CODE_24M,
          .flags = 0 },
        { .bitrate = 360,
          .hw_value = ATH5K_RATE_CODE_36M,
          .flags = 0 },
        { .bitrate = 480,
          .hw_value = ATH5K_RATE_CODE_48M,
          .flags = 0 },
        { .bitrate = 540,
          .hw_value = ATH5K_RATE_CODE_54M,
          .flags = 0 },
};

static inline u64 ath5k_extend_tsf(struct ath5k_hw *ah, u32 rstamp)
{
        u64 tsf = ath5k_hw_get_tsf64(ah);

        if ((tsf & 0x7fff) < rstamp)
                tsf -= 0x8000;

        return (tsf & ~0x7fff) | rstamp;
}

const char *
ath5k_chip_name(enum ath5k_srev_type type, u_int16_t 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;
}
static unsigned int ath5k_ioread32(void *hw_priv, u32 reg_offset)
{
        struct ath5k_hw *ah = (struct ath5k_hw *) hw_priv;
        return ath5k_hw_reg_read(ah, reg_offset);
}

static void ath5k_iowrite32(void *hw_priv, u32 val, u32 reg_offset)
{
        struct ath5k_hw *ah = (struct ath5k_hw *) hw_priv;
        ath5k_hw_reg_write(ah, val, reg_offset);
}

static const struct ath_ops ath5k_common_ops = {
        .read = ath5k_ioread32,
        .write = ath5k_iowrite32,
};

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

static int ath5k_reg_notifier(struct wiphy *wiphy, struct regulatory_request *request)
{
        struct ieee80211_hw *hw = wiphy_to_ieee80211_hw(wiphy);
        struct ath5k_hw *ah = hw->priv;
        struct ath_regulatory *regulatory = ath5k_hw_regulatory(ah);

        return ath_reg_notifier_apply(wiphy, request, regulatory);
}

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

/*
 * Returns true for the channel numbers used without all_channels modparam.
 */
static bool ath5k_is_standard_channel(short chan, enum ieee80211_band band)
{
        if (band == IEEE80211_BAND_2GHZ && chan <= 14)
                return true;

        return  /* UNII 1,2 */
                (((chan & 3) == 0 && chan >= 36 && chan <= 64) ||
                /* midband */
                ((chan & 3) == 0 && chan >= 100 && chan <= 140) ||
                /* UNII-3 */
                ((chan & 3) == 1 && chan >= 149 && chan <= 165) ||
                /* 802.11j 5.030-5.080 GHz (20MHz) */
                (chan == 8 || chan == 12 || chan == 16) ||
                /* 802.11j 4.9GHz (20MHz) */
                (chan == 184 || chan == 188 || chan == 192 || chan == 196));
}

static unsigned int
ath5k_setup_channels(struct ath5k_hw *ah, struct ieee80211_channel *channels,
                unsigned int mode, unsigned int max)
{
        unsigned int count, size, freq, ch;
        enum ieee80211_band band;

        switch (mode) {
        case AR5K_MODE_11A:
                /* 1..220, but 2GHz frequencies are filtered by check_channel */
                size = 220;
                band = IEEE80211_BAND_5GHZ;
                break;
        case AR5K_MODE_11B:
        case AR5K_MODE_11G:
                size = 26;
                band = IEEE80211_BAND_2GHZ;
                break;
        default:
                ATH5K_WARN(ah, "bad mode, not copying channels\n");
                return 0;
        }

        count = 0;
        for (ch = 1; ch <= size && count < max; ch++) {
                freq = ieee80211_channel_to_frequency(ch, band);

                if (freq == 0) /* mapping failed - not a standard channel */
                        continue;

                /* Write channel info, needed for ath5k_channel_ok() */
                channels[count].center_freq = freq;
                channels[count].band = band;
                channels[count].hw_value = mode;

                /* Check if channel is supported by the chipset */
                if (!ath5k_channel_ok(ah, &channels[count]))
                        continue;

                if (!modparam_all_channels &&
                    !ath5k_is_standard_channel(ch, band))
                        continue;

                count++;
        }

        return count;
}

static void
ath5k_setup_rate_idx(struct ath5k_hw *ah, struct ieee80211_supported_band *b)
{
        u8 i;

        for (i = 0; i < AR5K_MAX_RATES; i++)
                ah->rate_idx[b->band][i] = -1;

        for (i = 0; i < b->n_bitrates; i++) {
                ah->rate_idx[b->band][b->bitrates[i].hw_value] = i;
                if (b->bitrates[i].hw_value_short)
                        ah->rate_idx[b->band][b->bitrates[i].hw_value_short] = i;
        }
}

static int
ath5k_setup_bands(struct ieee80211_hw *hw)
{
        struct ath5k_hw *ah = hw->priv;
        struct ieee80211_supported_band *sband;
        int max_c, count_c = 0;
        int i;

        BUILD_BUG_ON(ARRAY_SIZE(ah->sbands) < IEEE80211_NUM_BANDS);
        max_c = ARRAY_SIZE(ah->channels);

        /* 2GHz band */
        sband = &ah->sbands[IEEE80211_BAND_2GHZ];
        sband->band = IEEE80211_BAND_2GHZ;
        sband->bitrates = &ah->rates[IEEE80211_BAND_2GHZ][0];

        if (test_bit(AR5K_MODE_11G, ah->ah_capabilities.cap_mode)) {
                /* G mode */
                memcpy(sband->bitrates, &ath5k_rates[0],
                       sizeof(struct ieee80211_rate) * 12);
                sband->n_bitrates = 12;

                sband->channels = ah->channels;
                sband->n_channels = ath5k_setup_channels(ah, sband->channels,
                                        AR5K_MODE_11G, max_c);

                hw->wiphy->bands[IEEE80211_BAND_2GHZ] = sband;
                count_c = sband->n_channels;
                max_c -= count_c;
        } else if (test_bit(AR5K_MODE_11B, ah->ah_capabilities.cap_mode)) {
                /* B mode */
                memcpy(sband->bitrates, &ath5k_rates[0],
                       sizeof(struct ieee80211_rate) * 4);
                sband->n_bitrates = 4;

                /* 5211 only supports B rates and uses 4bit rate codes
                 * (e.g normally we have 0x1B for 1M, but on 5211 we have 0x0B)
                 * fix them up here:
                 */
                if (ah->ah_version == AR5K_AR5211) {
                        for (i = 0; i < 4; i++) {
                                sband->bitrates[i].hw_value =
                                        sband->bitrates[i].hw_value & 0xF;
                                sband->bitrates[i].hw_value_short =
                                        sband->bitrates[i].hw_value_short & 0xF;
                        }
                }

                sband->channels = ah->channels;
                sband->n_channels = ath5k_setup_channels(ah, sband->channels,
                                        AR5K_MODE_11B, max_c);

                hw->wiphy->bands[IEEE80211_BAND_2GHZ] = sband;
                count_c = sband->n_channels;
                max_c -= count_c;
        }
        ath5k_setup_rate_idx(ah, sband);

        /* 5GHz band, A mode */
        if (test_bit(AR5K_MODE_11A, ah->ah_capabilities.cap_mode)) {
                sband = &ah->sbands[IEEE80211_BAND_5GHZ];
                sband->band = IEEE80211_BAND_5GHZ;
                sband->bitrates = &ah->rates[IEEE80211_BAND_5GHZ][0];

                memcpy(sband->bitrates, &ath5k_rates[4],
                       sizeof(struct ieee80211_rate) * 8);
                sband->n_bitrates = 8;

                sband->channels = &ah->channels[count_c];
                sband->n_channels = ath5k_setup_channels(ah, sband->channels,
                                        AR5K_MODE_11A, max_c);

                hw->wiphy->bands[IEEE80211_BAND_5GHZ] = sband;
        }
        ath5k_setup_rate_idx(ah, sband);

        ath5k_debug_dump_bands(ah);

        return 0;
}

/*
 * Set/change channels. We always reset the chip.
 * To accomplish this we must first cleanup any pending DMA,
 * then restart stuff after a la  ath5k_init.
 *
 * Called with ah->lock.
 */
int
ath5k_chan_set(struct ath5k_hw *ah, struct ieee80211_channel *chan)
{
        ATH5K_DBG(ah, ATH5K_DEBUG_RESET,
                  "channel set, resetting (%u -> %u MHz)\n",
                  ah->curchan->center_freq, chan->center_freq);

        /*
         * 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.
         */
        return ath5k_reset(ah, chan, true);
}

void ath5k_vif_iter(void *data, u8 *mac, struct ieee80211_vif *vif)
{
        struct ath5k_vif_iter_data *iter_data = data;
        int i;
        struct ath5k_vif *avf = (void *)vif->drv_priv;

        if (iter_data->hw_macaddr)
                for (i = 0; i < ETH_ALEN; i++)
                        iter_data->mask[i] &=
                                ~(iter_data->hw_macaddr[i] ^ mac[i]);

        if (!iter_data->found_active) {
                iter_data->found_active = true;
                memcpy(iter_data->active_mac, mac, ETH_ALEN);
        }

        if (iter_data->need_set_hw_addr && iter_data->hw_macaddr)
                if (compare_ether_addr(iter_data->hw_macaddr, mac) == 0)
                        iter_data->need_set_hw_addr = false;

        if (!iter_data->any_assoc) {
                if (avf->assoc)
                        iter_data->any_assoc = true;
        }

        /* Calculate combined mode - when APs are active, operate in AP mode.
         * Otherwise use the mode of the new interface. This can currently
         * only deal with combinations of APs and STAs. Only one ad-hoc
         * interfaces is allowed.
         */
        if (avf->opmode == NL80211_IFTYPE_AP)
                iter_data->opmode = NL80211_IFTYPE_AP;
        else {
                if (avf->opmode == NL80211_IFTYPE_STATION)
                        iter_data->n_stas++;
                if (iter_data->opmode == NL80211_IFTYPE_UNSPECIFIED)
                        iter_data->opmode = avf->opmode;
        }
}

void
ath5k_update_bssid_mask_and_opmode(struct ath5k_hw *ah,
                                   struct ieee80211_vif *vif)
{
        struct ath_common *common = ath5k_hw_common(ah);
        struct ath5k_vif_iter_data iter_data;
        u32 rfilt;

        /*
         * Use the hardware MAC address as reference, the hardware uses it
         * together with the BSSID mask when matching addresses.
         */
        iter_data.hw_macaddr = common->macaddr;
        memset(&iter_data.mask, 0xff, ETH_ALEN);
        iter_data.found_active = false;
        iter_data.need_set_hw_addr = true;
        iter_data.opmode = NL80211_IFTYPE_UNSPECIFIED;
        iter_data.n_stas = 0;

        if (vif)
                ath5k_vif_iter(&iter_data, vif->addr, vif);

        /* Get list of all active MAC addresses */
        ieee80211_iterate_active_interfaces_atomic(ah->hw, ath5k_vif_iter,
                                                   &iter_data);
        memcpy(ah->bssidmask, iter_data.mask, ETH_ALEN);

        ah->opmode = iter_data.opmode;
        if (ah->opmode == NL80211_IFTYPE_UNSPECIFIED)
                /* Nothing active, default to station mode */
                ah->opmode = NL80211_IFTYPE_STATION;

        ath5k_hw_set_opmode(ah, ah->opmode);
        ATH5K_DBG(ah, ATH5K_DEBUG_MODE, "mode setup opmode %d (%s)\n",
                  ah->opmode, ath_opmode_to_string(ah->opmode));

        if (iter_data.need_set_hw_addr && iter_data.found_active)
                ath5k_hw_set_lladdr(ah, iter_data.active_mac);

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

        /* Set up RX Filter */
        if (iter_data.n_stas > 1) {
                /* If you have multiple STA interfaces connected to
                 * different APs, ARPs are not received (most of the time?)
                 * Enabling PROMISC appears to fix that problem.
                 */
                ah->filter_flags |= AR5K_RX_FILTER_PROM;
        }

        rfilt = ah->filter_flags;
        ath5k_hw_set_rx_filter(ah, rfilt);
        ATH5K_DBG(ah, ATH5K_DEBUG_MODE, "RX filter 0x%x\n", rfilt);
}

static inline int
ath5k_hw_to_driver_rix(struct ath5k_hw *ah, int hw_rix)
{
        int rix;

        /* return base rate on errors */
        if (WARN(hw_rix < 0 || hw_rix >= AR5K_MAX_RATES,
                        "hw_rix out of bounds: %x\n", hw_rix))
                return 0;

        rix = ah->rate_idx[ah->curchan->band][hw_rix];
        if (WARN(rix < 0, "invalid hw_rix: %x\n", hw_rix))
                rix = 0;

        return rix;
}

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

static
struct sk_buff *ath5k_rx_skb_alloc(struct ath5k_hw *ah, dma_addr_t *skb_addr)
{
        struct ath_common *common = ath5k_hw_common(ah);
        struct sk_buff *skb;

        /*
         * Allocate buffer with headroom_needed space for the
         * fake physical layer header at the start.
         */
        skb = ath_rxbuf_alloc(common,
                              common->rx_bufsize,
                              GFP_ATOMIC);

        if (!skb) {
                ATH5K_ERR(ah, "can't alloc skbuff of size %u\n",
                                common->rx_bufsize);
                return NULL;
        }

        *skb_addr = dma_map_single(ah->dev,
                                   skb->data, common->rx_bufsize,
                                   DMA_FROM_DEVICE);

        if (unlikely(dma_mapping_error(ah->dev, *skb_addr))) {
                ATH5K_ERR(ah, "%s: DMA mapping failed\n", __func__);
                dev_kfree_skb(skb);
                return NULL;
        }
        return skb;
}

static int
ath5k_rxbuf_setup(struct ath5k_hw *ah, struct ath5k_buf *bf)
{
        struct sk_buff *skb = bf->skb;
        struct ath5k_desc *ds;
        int ret;

        if (!skb) {
                skb = ath5k_rx_skb_alloc(ah, &bf->skbaddr);
                if (!skb)
                        return -ENOMEM;
                bf->skb = skb;
        }

        /*
         * 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 ensure 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 ensures 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->skbaddr;
        ret = ath5k_hw_setup_rx_desc(ah, ds, ah->common.rx_bufsize, 0);
        if (ret) {
                ATH5K_ERR(ah, "%s: could not setup RX desc\n", __func__);
                return ret;
        }

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

static enum ath5k_pkt_type get_hw_packet_type(struct sk_buff *skb)
{
        struct ieee80211_hdr *hdr;
        enum ath5k_pkt_type htype;
        __le16 fc;

        hdr = (struct ieee80211_hdr *)skb->data;
        fc = hdr->frame_control;

        if (ieee80211_is_beacon(fc))
                htype = AR5K_PKT_TYPE_BEACON;
        else if (ieee80211_is_probe_resp(fc))
                htype = AR5K_PKT_TYPE_PROBE_RESP;
        else if (ieee80211_is_atim(fc))
                htype = AR5K_PKT_TYPE_ATIM;
        else if (ieee80211_is_pspoll(fc))
                htype = AR5K_PKT_TYPE_PSPOLL;
        else
                htype = AR5K_PKT_TYPE_NORMAL;

        return htype;
}

static int
ath5k_txbuf_setup(struct ath5k_hw *ah, struct ath5k_buf *bf,
                  struct ath5k_txq *txq, int padsize)
{
        struct ath5k_desc *ds = bf->desc;
        struct sk_buff *skb = bf->skb;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        unsigned int pktlen, flags, keyidx = AR5K_TXKEYIX_INVALID;
        struct ieee80211_rate *rate;
        unsigned int mrr_rate[3], mrr_tries[3];
        int i, ret;
        u16 hw_rate;
        u16 cts_rate = 0;
        u16 duration = 0;
        u8 rc_flags;

        flags = AR5K_TXDESC_INTREQ | AR5K_TXDESC_CLRDMASK;

        /* XXX endianness */
        bf->skbaddr = dma_map_single(ah->dev, skb->data, skb->len,
                        DMA_TO_DEVICE);

        rate = ieee80211_get_tx_rate(ah->hw, info);
        if (!rate) {
                ret = -EINVAL;
                goto err_unmap;
        }

        if (info->flags & IEEE80211_TX_CTL_NO_ACK)
                flags |= AR5K_TXDESC_NOACK;

        rc_flags = info->control.rates[0].flags;
        hw_rate = (rc_flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE) ?
                rate->hw_value_short : rate->hw_value;

        pktlen = skb->len;

        /* 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 (info->control.hw_key) {
                keyidx = info->control.hw_key->hw_key_idx;
                pktlen += info->control.hw_key->icv_len;
        }
        if (rc_flags & IEEE80211_TX_RC_USE_RTS_CTS) {
                flags |= AR5K_TXDESC_RTSENA;
                cts_rate = ieee80211_get_rts_cts_rate(ah->hw, info)->hw_value;
                duration = le16_to_cpu(ieee80211_rts_duration(ah->hw,
                        info->control.vif, pktlen, info));
        }
        if (rc_flags & IEEE80211_TX_RC_USE_CTS_PROTECT) {
                flags |= AR5K_TXDESC_CTSENA;
                cts_rate = ieee80211_get_rts_cts_rate(ah->hw, info)->hw_value;
                duration = le16_to_cpu(ieee80211_ctstoself_duration(ah->hw,
                        info->control.vif, pktlen, info));
        }
        ret = ah->ah_setup_tx_desc(ah, ds, pktlen,
                ieee80211_get_hdrlen_from_skb(skb), padsize,
                get_hw_packet_type(skb),
                (ah->power_level * 2),
                hw_rate,
                info->control.rates[0].count, keyidx, ah->ah_tx_ant, flags,
                cts_rate, duration);
        if (ret)
                goto err_unmap;

        /* Set up MRR descriptor */
        if (ah->ah_capabilities.cap_has_mrr_support) {
                memset(mrr_rate, 0, sizeof(mrr_rate));
                memset(mrr_tries, 0, sizeof(mrr_tries));
                for (i = 0; i < 3; i++) {
                        rate = ieee80211_get_alt_retry_rate(ah->hw, info, i);
                        if (!rate)
                                break;

                        mrr_rate[i] = rate->hw_value;
                        mrr_tries[i] = info->control.rates[i + 1].count;
                }

                ath5k_hw_setup_mrr_tx_desc(ah, ds,
                        mrr_rate[0], mrr_tries[0],
                        mrr_rate[1], mrr_tries[1],
                        mrr_rate[2], mrr_tries[2]);
        }

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

        spin_lock_bh(&txq->lock);
        list_add_tail(&bf->list, &txq->q);
        txq->txq_len++;
        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);
        mmiowb();
        spin_unlock_bh(&txq->lock);

        return 0;
err_unmap:
        dma_unmap_single(ah->dev, bf->skbaddr, skb->len, DMA_TO_DEVICE);
        return ret;
}

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

static int
ath5k_desc_alloc(struct ath5k_hw *ah)
{
        struct ath5k_desc *ds;
        struct ath5k_buf *bf;
        dma_addr_t da;
        unsigned int i;
        int ret;

        /* allocate descriptors */
        ah->desc_len = sizeof(struct ath5k_desc) *
                        (ATH_TXBUF + ATH_RXBUF + ATH_BCBUF + 1);

        ah->desc = dma_alloc_coherent(ah->dev, ah->desc_len,
                                &ah->desc_daddr, GFP_KERNEL);
        if (ah->desc == NULL) {
                ATH5K_ERR(ah, "can't allocate descriptors\n");
                ret = -ENOMEM;
                goto err;
        }
        ds = ah->desc;
        da = ah->desc_daddr;
        ATH5K_DBG(ah, ATH5K_DEBUG_ANY, "DMA map: %p (%zu) -> %llx\n",
                ds, ah->desc_len, (unsigned long long)ah->desc_daddr);

        bf = kcalloc(1 + ATH_TXBUF + ATH_RXBUF + ATH_BCBUF,
                        sizeof(struct ath5k_buf), GFP_KERNEL);
        if (bf == NULL) {
                ATH5K_ERR(ah, "can't allocate bufptr\n");
                ret = -ENOMEM;
                goto err_free;
        }
        ah->bufptr = bf;

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

        INIT_LIST_HEAD(&ah->txbuf);
        ah->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, &ah->txbuf);
        }

        /* beacon buffers */
        INIT_LIST_HEAD(&ah->bcbuf);
        for (i = 0; i < ATH_BCBUF; i++, bf++, ds++, da += sizeof(*ds)) {
                bf->desc = ds;
                bf->daddr = da;
                list_add_tail(&bf->list, &ah->bcbuf);
        }

        return 0;
err_free:
        dma_free_coherent(ah->dev, ah->desc_len, ah->desc, ah->desc_daddr);
err:
        ah->desc = NULL;
        return ret;
}

void
ath5k_txbuf_free_skb(struct ath5k_hw *ah, struct ath5k_buf *bf)
{
        BUG_ON(!bf);
        if (!bf->skb)
                return;
        dma_unmap_single(ah->dev, bf->skbaddr, bf->skb->len,
                        DMA_TO_DEVICE);
        dev_kfree_skb_any(bf->skb);
        bf->skb = NULL;
        bf->skbaddr = 0;
        bf->desc->ds_data = 0;
}

void
ath5k_rxbuf_free_skb(struct ath5k_hw *ah, struct ath5k_buf *bf)
{
        struct ath_common *common = ath5k_hw_common(ah);

        BUG_ON(!bf);
        if (!bf->skb)
                return;
        dma_unmap_single(ah->dev, bf->skbaddr, common->rx_bufsize,
                        DMA_FROM_DEVICE);
        dev_kfree_skb_any(bf->skb);
        bf->skb = NULL;
        bf->skbaddr = 0;
        bf->desc->ds_data = 0;
}

static void
ath5k_desc_free(struct ath5k_hw *ah)
{
        struct ath5k_buf *bf;

        list_for_each_entry(bf, &ah->txbuf, list)
                ath5k_txbuf_free_skb(ah, bf);
        list_for_each_entry(bf, &ah->rxbuf, list)
                ath5k_rxbuf_free_skb(ah, bf);
        list_for_each_entry(bf, &ah->bcbuf, list)
                ath5k_txbuf_free_skb(ah, bf);

        /* Free memory associated with all descriptors */
        dma_free_coherent(ah->dev, ah->desc_len, ah->desc, ah->desc_daddr);
        ah->desc = NULL;
        ah->desc_daddr = 0;

        kfree(ah->bufptr);
        ah->bufptr = NULL;
}


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

static struct ath5k_txq *
ath5k_txq_setup(struct ath5k_hw *ah,
                int qtype, int subtype)
{
        struct ath5k_txq *txq;
        struct ath5k_txq_info qi = {
                .tqi_subtype = subtype,
                /* XXX: default values not correct for B and XR channels,
                 * but who cares? */
                .tqi_aifs = AR5K_TUNE_AIFS,
                .tqi_cw_min = AR5K_TUNE_CWMIN,
                .tqi_cw_max = AR5K_TUNE_CWMAX
        };
        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 we wait 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) {
                /*
                 * NB: don't print a message, this happens
                 * normally on parts with too few tx queues
                 */
                return ERR_PTR(qnum);
        }
        txq = &ah->txqs[qnum];
        if (!txq->setup) {
                txq->qnum = qnum;
                txq->link = NULL;
                INIT_LIST_HEAD(&txq->q);
                spin_lock_init(&txq->lock);
                txq->setup = true;
                txq->txq_len = 0;
                txq->txq_max = ATH5K_TXQ_LEN_MAX;
                txq->txq_poll_mark = false;
                txq->txq_stuck = 0;
        }
        return &ah->txqs[qnum];
}

static int
ath5k_beaconq_setup(struct ath5k_hw *ah)
{
        struct ath5k_txq_info qi = {
                /* XXX: default values not correct for B and XR channels,
                 * but who cares? */
                .tqi_aifs = AR5K_TUNE_AIFS,
                .tqi_cw_min = AR5K_TUNE_CWMIN,
                .tqi_cw_max = AR5K_TUNE_CWMAX,
                /* NB: for dynamic turbo, don't enable any other interrupts */
                .tqi_flags = AR5K_TXQ_FLAG_TXDESCINT_ENABLE
        };

        return ath5k_hw_setup_tx_queue(ah, AR5K_TX_QUEUE_BEACON, &qi);
}

static int
ath5k_beaconq_config(struct ath5k_hw *ah)
{
        struct ath5k_txq_info qi;
        int ret;

        ret = ath5k_hw_get_tx_queueprops(ah, ah->bhalq, &qi);
        if (ret)
                goto err;

        if (ah->opmode == NL80211_IFTYPE_AP ||
            ah->opmode == NL80211_IFTYPE_MESH_POINT) {
                /*
                 * Always burst out beacon and CAB traffic
                 * (aifs = cwmin = cwmax = 0)
                 */
                qi.tqi_aifs = 0;
                qi.tqi_cw_min = 0;
                qi.tqi_cw_max = 0;
        } else if (ah->opmode == NL80211_IFTYPE_ADHOC) {
                /*
                 * Adhoc mode; backoff between 0 and (2 * cw_min).
                 */
                qi.tqi_aifs = 0;
                qi.tqi_cw_min = 0;
                qi.tqi_cw_max = 2 * AR5K_TUNE_CWMIN;
        }

        ATH5K_DBG(ah, ATH5K_DEBUG_BEACON,
                "beacon queueprops tqi_aifs:%d tqi_cw_min:%d tqi_cw_max:%d\n",
                qi.tqi_aifs, qi.tqi_cw_min, qi.tqi_cw_max);

        ret = ath5k_hw_set_tx_queueprops(ah, ah->bhalq, &qi);
        if (ret) {
                ATH5K_ERR(ah, "%s: unable to update parameters for beacon "
                        "hardware queue!\n", __func__);
                goto err;
        }
        ret = ath5k_hw_reset_tx_queue(ah, ah->bhalq); /* push to h/w */
        if (ret)
                goto err;

        /* reconfigure cabq with ready time to 80% of beacon_interval */
        ret = ath5k_hw_get_tx_queueprops(ah, AR5K_TX_QUEUE_ID_CAB, &qi);
        if (ret)
                goto err;

        qi.tqi_ready_time = (ah->bintval * 80) / 100;
        ret = ath5k_hw_set_tx_queueprops(ah, AR5K_TX_QUEUE_ID_CAB, &qi);
        if (ret)
                goto err;

        ret = ath5k_hw_reset_tx_queue(ah, AR5K_TX_QUEUE_ID_CAB);
err:
        return ret;
}

/**
 * ath5k_drain_tx_buffs - Empty tx buffers
 *
 * @ah The &struct ath5k_hw
 *
 * Empty tx buffers from all queues in preparation
 * of a reset or during shutdown.
 *
 * NB:  this assumes output has been stopped and
 *      we do not need to block ath5k_tx_tasklet
 */
static void
ath5k_drain_tx_buffs(struct ath5k_hw *ah)
{
        struct ath5k_txq *txq;
        struct ath5k_buf *bf, *bf0;
        int i;

        for (i = 0; i < ARRAY_SIZE(ah->txqs); i++) {
                if (ah->txqs[i].setup) {
                        txq = &ah->txqs[i];
                        spin_lock_bh(&txq->lock);
                        list_for_each_entry_safe(bf, bf0, &txq->q, list) {
                                ath5k_debug_printtxbuf(ah, bf);

                                ath5k_txbuf_free_skb(ah, bf);

                                spin_lock_bh(&ah->txbuflock);
                                list_move_tail(&bf->list, &ah->txbuf);
                                ah->txbuf_len++;
                                txq->txq_len--;
                                spin_unlock_bh(&ah->txbuflock);
                        }
                        txq->link = NULL;
                        txq->txq_poll_mark = false;
                        spin_unlock_bh(&txq->lock);
                }
        }
}

static void
ath5k_txq_release(struct ath5k_hw *ah)
{
        struct ath5k_txq *txq = ah->txqs;
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(ah->txqs); i++, txq++)
                if (txq->setup) {
                        ath5k_hw_release_tx_queue(ah, txq->qnum);
                        txq->setup = false;
                }
}


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

/*
 * Enable the receive h/w following a reset.
 */
static int
ath5k_rx_start(struct ath5k_hw *ah)
{
        struct ath_common *common = ath5k_hw_common(ah);
        struct ath5k_buf *bf;
        int ret;

        common->rx_bufsize = roundup(IEEE80211_MAX_FRAME_LEN, common->cachelsz);

        ATH5K_DBG(ah, ATH5K_DEBUG_RESET, "cachelsz %u rx_bufsize %u\n",
                  common->cachelsz, common->rx_bufsize);

        spin_lock_bh(&ah->rxbuflock);
        ah->rxlink = NULL;
        list_for_each_entry(bf, &ah->rxbuf, list) {
                ret = ath5k_rxbuf_setup(ah, bf);
                if (ret != 0) {
                        spin_unlock_bh(&ah->rxbuflock);
                        goto err;
                }
        }
        bf = list_first_entry(&ah->rxbuf, struct ath5k_buf, list);
        ath5k_hw_set_rxdp(ah, bf->daddr);
        spin_unlock_bh(&ah->rxbuflock);

        ath5k_hw_start_rx_dma(ah);      /* enable recv descriptors */
        ath5k_update_bssid_mask_and_opmode(ah, NULL); /* set filters, etc. */
        ath5k_hw_start_rx_pcu(ah);      /* re-enable PCU/DMA engine */

        return 0;
err:
        return ret;
}

/*
 * Disable the receive logic on PCU (DRU)
 * In preparation for a shutdown.
 *
 * Note: Doesn't stop rx DMA, ath5k_hw_dma_stop
 * does.
 */
static void
ath5k_rx_stop(struct ath5k_hw *ah)
{

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

        ath5k_debug_printrxbuffs(ah);
}

static unsigned int
ath5k_rx_decrypted(struct ath5k_hw *ah, struct sk_buff *skb,
                   struct ath5k_rx_status *rs)
{
        struct ath_common *common = ath5k_hw_common(ah);
        struct ieee80211_hdr *hdr = (void *)skb->data;
        unsigned int keyix, hlen;

        if (!(rs->rs_status & AR5K_RXERR_DECRYPT) &&
                        rs->rs_keyix != AR5K_RXKEYIX_INVALID)
                return RX_FLAG_DECRYPTED;

        /* Apparently when a default key is used to decrypt the packet
           the hw does not set the index used to decrypt.  In such cases
           get the index from the packet. */
        hlen = ieee80211_hdrlen(hdr->frame_control);
        if (ieee80211_has_protected(hdr->frame_control) &&
            !(rs->rs_status & AR5K_RXERR_DECRYPT) &&
            skb->len >= hlen + 4) {
                keyix = skb->data[hlen + 3] >> 6;

                if (test_bit(keyix, common->keymap))
                        return RX_FLAG_DECRYPTED;
        }

        return 0;
}


static void
ath5k_check_ibss_tsf(struct ath5k_hw *ah, struct sk_buff *skb,
                     struct ieee80211_rx_status *rxs)
{
        struct ath_common *common = ath5k_hw_common(ah);
        u64 tsf, bc_tstamp;
        u32 hw_tu;
        struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)skb->data;

        if (ieee80211_is_beacon(mgmt->frame_control) &&
            le16_to_cpu(mgmt->u.beacon.capab_info) & WLAN_CAPABILITY_IBSS &&
            memcmp(mgmt->bssid, common->curbssid, ETH_ALEN) == 0) {
                /*
                 * Received an IBSS beacon with the same BSSID. Hardware *must*
                 * have updated the local TSF. We have to work around various
                 * hardware bugs, though...
                 */
                tsf = ath5k_hw_get_tsf64(ah);
                bc_tstamp = le64_to_cpu(mgmt->u.beacon.timestamp);
                hw_tu = TSF_TO_TU(tsf);

                ATH5K_DBG_UNLIMIT(ah, ATH5K_DEBUG_BEACON,
                        "beacon %llx mactime %llx (diff %lld) tsf now %llx\n",
                        (unsigned long long)bc_tstamp,
                        (unsigned long long)rxs->mactime,
                        (unsigned long long)(rxs->mactime - bc_tstamp),
                        (unsigned long long)tsf);

                /*
                 * Sometimes the HW will give us a wrong tstamp in the rx
                 * status, causing the timestamp extension to go wrong.
                 * (This seems to happen especially with beacon frames bigger
                 * than 78 byte (incl. FCS))
                 * But we know that the receive timestamp must be later than the
                 * timestamp of the beacon since HW must have synced to that.
                 *
                 * NOTE: here we assume mactime to be after the frame was
                 * received, not like mac80211 which defines it at the start.
                 */
                if (bc_tstamp > rxs->mactime) {
                        ATH5K_DBG_UNLIMIT(ah, ATH5K_DEBUG_BEACON,
                                "fixing mactime from %llx to %llx\n",
                                (unsigned long long)rxs->mactime,
                                (unsigned long long)tsf);
                        rxs->mactime = tsf;
                }

                /*
                 * Local TSF might have moved higher than our beacon timers,
                 * in that case we have to update them to continue sending
                 * beacons. This also takes care of synchronizing beacon sending
                 * times with other stations.
                 */
                if (hw_tu >= ah->nexttbtt)
                        ath5k_beacon_update_timers(ah, bc_tstamp);

                /* Check if the beacon timers are still correct, because a TSF
                 * update might have created a window between them - for a
                 * longer description see the comment of this function: */
                if (!ath5k_hw_check_beacon_timers(ah, ah->bintval)) {
                        ath5k_beacon_update_timers(ah, bc_tstamp);
                        ATH5K_DBG_UNLIMIT(ah, ATH5K_DEBUG_BEACON,
                                "fixed beacon timers after beacon receive\n");
                }
        }
}

static void
ath5k_update_beacon_rssi(struct ath5k_hw *ah, struct sk_buff *skb, int rssi)
{
        struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)skb->data;
        struct ath_common *common = ath5k_hw_common(ah);

        /* only beacons from our BSSID */
        if (!ieee80211_is_beacon(mgmt->frame_control) ||
            memcmp(mgmt->bssid, common->curbssid, ETH_ALEN) != 0)
                return;

        ewma_add(&ah->ah_beacon_rssi_avg, rssi);

        /* in IBSS mode we should keep RSSI statistics per neighbour */
        /* le16_to_cpu(mgmt->u.beacon.capab_info) & WLAN_CAPABILITY_IBSS */
}

/*
 * Compute padding position. skb must contain an IEEE 802.11 frame
 */
static int ath5k_common_padpos(struct sk_buff *skb)
{
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
        __le16 frame_control = hdr->frame_control;
        int padpos = 24;

        if (ieee80211_has_a4(frame_control))
                padpos += ETH_ALEN;

        if (ieee80211_is_data_qos(frame_control))
                padpos += IEEE80211_QOS_CTL_LEN;

        return padpos;
}

/*
 * This function expects an 802.11 frame and returns the number of
 * bytes added, or -1 if we don't have enough header room.
 */
static int ath5k_add_padding(struct sk_buff *skb)
{
        int padpos = ath5k_common_padpos(skb);
        int padsize = padpos & 3;

        if (padsize && skb->len > padpos) {

                if (skb_headroom(skb) < padsize)
                        return -1;

                skb_push(skb, padsize);
                memmove(skb->data, skb->data + padsize, padpos);
                return padsize;
        }

        return 0;
}

/*
 * The MAC header is padded to have 32-bit boundary if the
 * packet payload is non-zero. The general calculation for
 * padsize would take into account odd header lengths:
 * padsize = 4 - (hdrlen & 3); however, since only
 * even-length headers are used, padding can only be 0 or 2
 * bytes and we can optimize this a bit.  We must not try to
 * remove padding from short control frames that do not have a
 * payload.
 *
 * This function expects an 802.11 frame and returns the number of
 * bytes removed.
 */
static int ath5k_remove_padding(struct sk_buff *skb)
{
        int padpos = ath5k_common_padpos(skb);
        int padsize = padpos & 3;

        if (padsize && skb->len >= padpos + padsize) {
                memmove(skb->data + padsize, skb->data, padpos);
                skb_pull(skb, padsize);
                return padsize;
        }

        return 0;
}

static void
ath5k_receive_frame(struct ath5k_hw *ah, struct sk_buff *skb,
                    struct ath5k_rx_status *rs)
{
        struct ieee80211_rx_status *rxs;

        ath5k_remove_padding(skb);

        rxs = IEEE80211_SKB_RXCB(skb);

        rxs->flag = 0;
        if (unlikely(rs->rs_status & AR5K_RXERR_MIC))
                rxs->flag |= RX_FLAG_MMIC_ERROR;

        /*
         * always extend the mac timestamp, since this information is
         * also needed for proper IBSS merging.
         *
         * XXX: it might be too late to do it here, since rs_tstamp is
         * 15bit only. that means TSF extension has to be done within
         * 32768usec (about 32ms). it might be necessary to move this to
         * the interrupt handler, like it is done in madwifi.
         *
         * Unfortunately we don't know when the hardware takes the rx
         * timestamp (beginning of phy frame, data frame, end of rx?).
         * The only thing we know is that it is hardware specific...
         * On AR5213 it seems the rx timestamp is at the end of the
         * frame, but I'm not sure.
         *
         * NOTE: mac80211 defines mactime at the beginning of the first
         * data symbol. Since we don't have any time references it's
         * impossible to comply to that. This affects IBSS merge only
         * right now, so it's not too bad...
         */
        rxs->mactime = ath5k_extend_tsf(ah, rs->rs_tstamp);
        rxs->flag |= RX_FLAG_MACTIME_MPDU;

        rxs->freq = ah->curchan->center_freq;
        rxs->band = ah->curchan->band;

        rxs->signal = ah->ah_noise_floor + rs->rs_rssi;

        rxs->antenna = rs->rs_antenna;

        if (rs->rs_antenna > 0 && rs->rs_antenna < 5)
                ah->stats.antenna_rx[rs->rs_antenna]++;
        else
                ah->stats.antenna_rx[0]++; /* invalid */

        rxs->rate_idx = ath5k_hw_to_driver_rix(ah, rs->rs_rate);
        rxs->flag |= ath5k_rx_decrypted(ah, skb, rs);

        if (rxs->rate_idx >= 0 && rs->rs_rate ==
            ah->sbands[ah->curchan->band].bitrates[rxs->rate_idx].hw_value_short)
                rxs->flag |= RX_FLAG_SHORTPRE;

        trace_ath5k_rx(ah, skb);

        ath5k_update_beacon_rssi(ah, skb, rs->rs_rssi);

        /* check beacons in IBSS mode */
        if (ah->opmode == NL80211_IFTYPE_ADHOC)
                ath5k_check_ibss_tsf(ah, skb, rxs);

        ieee80211_rx(ah->hw, skb);
}

/** ath5k_frame_receive_ok() - Do we want to receive this frame or not?
 *
 * Check if we want to further process this frame or not. Also update
 * statistics. Return true if we want this frame, false if not.
 */
static bool
ath5k_receive_frame_ok(struct ath5k_hw *ah, struct ath5k_rx_status *rs)
{
        ah->stats.rx_all_count++;
        ah->stats.rx_bytes_count += rs->rs_datalen;

        if (unlikely(rs->rs_status)) {
                if (rs->rs_status & AR5K_RXERR_CRC)
                        ah->stats.rxerr_crc++;
                if (rs->rs_status & AR5K_RXERR_FIFO)
                        ah->stats.rxerr_fifo++;
                if (rs->rs_status & AR5K_RXERR_PHY) {
                        ah->stats.rxerr_phy++;
                        if (rs->rs_phyerr > 0 && rs->rs_phyerr < 32)
                                ah->stats.rxerr_phy_code[rs->rs_phyerr]++;
                        return false;
                }
                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
                         */
                        ah->stats.rxerr_decrypt++;
                        if (rs->rs_keyix == AR5K_RXKEYIX_INVALID &&
                            !(rs->rs_status & AR5K_RXERR_CRC))
                                return true;
                }
                if (rs->rs_status & AR5K_RXERR_MIC) {
                        ah->stats.rxerr_mic++;
                        return true;
                }

                /* reject any frames with non-crypto errors */
                if (rs->rs_status & ~(AR5K_RXERR_DECRYPT))
                        return false;
        }

        if (unlikely(rs->rs_more)) {
                ah->stats.rxerr_jumbo++;
                return false;
        }
        return true;
}

static void
ath5k_set_current_imask(struct ath5k_hw *ah)
{
        enum ath5k_int imask;
        unsigned long flags;

        spin_lock_irqsave(&ah->irqlock, flags);
        imask = ah->imask;
        if (ah->rx_pending)
                imask &= ~AR5K_INT_RX_ALL;
        if (ah->tx_pending)
                imask &= ~AR5K_INT_TX_ALL;
        ath5k_hw_set_imr(ah, imask);
        spin_unlock_irqrestore(&ah->irqlock, flags);
}

static void
ath5k_tasklet_rx(unsigned long data)
{
        struct ath5k_rx_status rs = {};
        struct sk_buff *skb, *next_skb;
        dma_addr_t next_skb_addr;
        struct ath5k_hw *ah = (void *)data;
        struct ath_common *common = ath5k_hw_common(ah);
        struct ath5k_buf *bf;
        struct ath5k_desc *ds;
        int ret;

        spin_lock(&ah->rxbuflock);
        if (list_empty(&ah->rxbuf)) {
                ATH5K_WARN(ah, "empty rx buf pool\n");
                goto unlock;
        }
        do {
                bf = list_first_entry(&ah->rxbuf, struct ath5k_buf, list);
                BUG_ON(bf->skb == NULL);
                skb = bf->skb;
                ds = bf->desc;

                /* bail if HW is still using self-linked descriptor */
                if (ath5k_hw_get_rxdp(ah) == bf->daddr)
                        break;

                ret = ah->ah_proc_rx_desc(ah, ds, &rs);
                if (unlikely(ret == -EINPROGRESS))
                        break;
                else if (unlikely(ret)) {
                        ATH5K_ERR(ah, "error in processing rx descriptor\n");
                        ah->stats.rxerr_proc++;
                        break;
                }

                if (ath5k_receive_frame_ok(ah, &rs)) {
                        next_skb = ath5k_rx_skb_alloc(ah, &next_skb_addr);

                        /*
                         * If we can't replace bf->skb with a new skb under
                         * memory pressure, just skip this packet
                         */
                        if (!next_skb)
                                goto next;

                        dma_unmap_single(ah->dev, bf->skbaddr,
                                         common->rx_bufsize,
                                         DMA_FROM_DEVICE);

                        skb_put(skb, rs.rs_datalen);

                        ath5k_receive_frame(ah, skb, &rs);

                        bf->skb = next_skb;
                        bf->skbaddr = next_skb_addr;
                }
next:
                list_move_tail(&bf->list, &ah->rxbuf);
        } while (ath5k_rxbuf_setup(ah, bf) == 0);
unlock:
        spin_unlock(&ah->rxbuflock);
        ah->rx_pending = false;
        ath5k_set_current_imask(ah);
}


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

void
ath5k_tx_queue(struct ieee80211_hw *hw, struct sk_buff *skb,
               struct ath5k_txq *txq)
{
        struct ath5k_hw *ah = hw->priv;
        struct ath5k_buf *bf;
        unsigned long flags;
        int padsize;

        trace_ath5k_tx(ah, skb, txq);

        /*
         * The hardware expects the header padded to 4 byte boundaries.
         * If this is not the case, we add the padding after the header.
         */
        padsize = ath5k_add_padding(skb);
        if (padsize < 0) {
                ATH5K_ERR(ah, "tx hdrlen not %%4: not enough"
                          " headroom to pad");
                goto drop_packet;
        }

        if (txq->txq_len >= txq->txq_max &&
            txq->qnum <= AR5K_TX_QUEUE_ID_DATA_MAX)
                ieee80211_stop_queue(hw, txq->qnum);

        spin_lock_irqsave(&ah->txbuflock, flags);
        if (list_empty(&ah->txbuf)) {
                ATH5K_ERR(ah, "no further txbuf available, dropping packet\n");
                spin_unlock_irqrestore(&ah->txbuflock, flags);
                ieee80211_stop_queues(hw);
                goto drop_packet;
        }
        bf = list_first_entry(&ah->txbuf, struct ath5k_buf, list);
        list_del(&bf->list);
        ah->txbuf_len--;
        if (list_empty(&ah->txbuf))
                ieee80211_stop_queues(hw);
        spin_unlock_irqrestore(&ah->txbuflock, flags);

        bf->skb = skb;

        if (ath5k_txbuf_setup(ah, bf, txq, padsize)) {
                bf->skb = NULL;
                spin_lock_irqsave(&ah->txbuflock, flags);
                list_add_tail(&bf->list, &ah->txbuf);
                ah->txbuf_len++;
                spin_unlock_irqrestore(&ah->txbuflock, flags);
                goto drop_packet;
        }
        return;

drop_packet:
        dev_kfree_skb_any(skb);
}

static void
ath5k_tx_frame_completed(struct ath5k_hw *ah, struct sk_buff *skb,
                         struct ath5k_txq *txq, struct ath5k_tx_status *ts)
{
        struct ieee80211_tx_info *info;
        u8 tries[3];
        int i;

        ah->stats.tx_all_count++;
        ah->stats.tx_bytes_count += skb->len;
        info = IEEE80211_SKB_CB(skb);

        tries[0] = info->status.rates[0].count;
        tries[1] = info->status.rates[1].count;
        tries[2] = info->status.rates[2].count;

        ieee80211_tx_info_clear_status(info);

        for (i = 0; i < ts->ts_final_idx; i++) {
                struct ieee80211_tx_rate *r =
                        &info->status.rates[i];

                r->count = tries[i];
        }

        info->status.rates[ts->ts_final_idx].count = ts->ts_final_retry;
        info->status.rates[ts->ts_final_idx + 1].idx = -1;

        if (unlikely(ts->ts_status)) {
                ah->stats.ack_fail++;
                if (ts->ts_status & AR5K_TXERR_FILT) {
                        info->flags |= IEEE80211_TX_STAT_TX_FILTERED;
                        ah->stats.txerr_filt++;
                }
                if (ts->ts_status & AR5K_TXERR_XRETRY)
                        ah->stats.txerr_retry++;
                if (ts->ts_status & AR5K_TXERR_FIFO)
                        ah->stats.txerr_fifo++;
        } else {
                info->flags |= IEEE80211_TX_STAT_ACK;
                info->status.ack_signal = ts->ts_rssi;

                /* count the successful attempt as well */
                info->status.rates[ts->ts_final_idx].count++;
        }

        /*
        * Remove MAC header padding before giving the frame
        * back to mac80211.
        */
        ath5k_remove_padding(skb);

        if (ts->ts_antenna > 0 && ts->ts_antenna < 5)
                ah->stats.antenna_tx[ts->ts_antenna]++;
        else
                ah->stats.antenna_tx[0]++; /* invalid */

        trace_ath5k_tx_complete(ah, skb, txq, ts);
        ieee80211_tx_status(ah->hw, skb);
}

static void
ath5k_tx_processq(struct ath5k_hw *ah, struct ath5k_txq *txq)
{
        struct ath5k_tx_status ts = {};
        struct ath5k_buf *bf, *bf0;
        struct ath5k_desc *ds;
        struct sk_buff *skb;
        int ret;

        spin_lock(&txq->lock);
        list_for_each_entry_safe(bf, bf0, &txq->q, list) {

                txq->txq_poll_mark = false;

                /* skb might already have been processed last time. */
                if (bf->skb != NULL) {
                        ds = bf->desc;

                        ret = ah->ah_proc_tx_desc(ah, ds, &ts);
                        if (unlikely(ret == -EINPROGRESS))
                                break;
                        else if (unlikely(ret)) {
                                ATH5K_ERR(ah,
                                        "error %d while processing "
                                        "queue %u\n", ret, txq->qnum);
                                break;
                        }

                        skb = bf->skb;
                        bf->skb = NULL;

                        dma_unmap_single(ah->dev, bf->skbaddr, skb->len,
                                        DMA_TO_DEVICE);
                        ath5k_tx_frame_completed(ah, skb, txq, &ts);
                }

                /*
                 * It's possible that the hardware can say the buffer is
                 * completed when it hasn't yet loaded the ds_link from
                 * host memory and moved on.
                 * Always keep the last descriptor to avoid HW races...
                 */
                if (ath5k_hw_get_txdp(ah, txq->qnum) != bf->daddr) {
                        spin_lock(&ah->txbuflock);
                        list_move_tail(&bf->list, &ah->txbuf);
                        ah->txbuf_len++;
                        txq->txq_len--;
                        spin_unlock(&ah->txbuflock);
                }
        }
        spin_unlock(&txq->lock);
        if (txq->txq_len < ATH5K_TXQ_LEN_LOW && txq->qnum < 4)
                ieee80211_wake_queue(ah->hw, txq->qnum);
}

static void
ath5k_tasklet_tx(unsigned long data)
{
        int i;
        struct ath5k_hw *ah = (void *)data;

        for (i = 0; i < AR5K_NUM_TX_QUEUES; i++)
                if (ah->txqs[i].setup && (ah->ah_txq_isr_txok_all & BIT(i)))
                        ath5k_tx_processq(ah, &ah->txqs[i]);

        ah->tx_pending = false;
        ath5k_set_current_imask(ah);
}


/*****************\
* Beacon handling *
\*****************/

/*
 * Setup the beacon frame for transmit.
 */
static int
ath5k_beacon_setup(struct ath5k_hw *ah, struct ath5k_buf *bf)
{
        struct sk_buff *skb = bf->skb;
        struct  ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct ath5k_desc *ds;
        int ret = 0;
        u8 antenna;
        u32 flags;
        const int padsize = 0;

        bf->skbaddr = dma_map_single(ah->dev, skb->data, skb->len,
                        DMA_TO_DEVICE);
        ATH5K_DBG(ah, ATH5K_DEBUG_BEACON, "skb %p [data %p len %u] "
                        "skbaddr %llx\n", skb, skb->data, skb->len,
                        (unsigned long long)bf->skbaddr);

        if (dma_mapping_error(ah->dev, bf->skbaddr)) {
                ATH5K_ERR(ah, "beacon DMA mapping failed\n");
                dev_kfree_skb_any(skb);
                bf->skb = NULL;
                return -EIO;
        }

        ds = bf->desc;
        antenna = ah->ah_tx_ant;

        flags = AR5K_TXDESC_NOACK;
        if (ah->opmode == NL80211_IFTYPE_ADHOC && ath5k_hw_hasveol(ah)) {
                ds->ds_link = bf->daddr;        /* self-linked */
                flags |= AR5K_TXDESC_VEOL;
        } else
                ds->ds_link = 0;

        /*
         * If we use multiple antennas on AP and use
         * the Sectored AP scenario, switch antenna every
         * 4 beacons to make sure everybody hears our AP.
         * When a client tries to associate, hw will keep
         * track of the tx antenna to be used for this client
         * automatically, based on ACKed packets.
         *
         * Note: AP still listens and transmits RTS on the
         * default antenna which is supposed to be an omni.
         *
         * Note2: On sectored scenarios it's possible to have
         * multiple antennas (1 omni -- the default -- and 14
         * sectors), so if we choose to actually support this
         * mode, we need to allow the user to set how many antennas
         * we have and tweak the code below to send beacons
         * on all of them.
         */
        if (ah->ah_ant_mode == AR5K_ANTMODE_SECTOR_AP)
                antenna = ah->bsent & 4 ? 2 : 1;


        /* 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) */
        ds->ds_data = bf->skbaddr;
        ret = ah->ah_setup_tx_desc(ah, ds, skb->len,
                        ieee80211_get_hdrlen_from_skb(skb), padsize,
                        AR5K_PKT_TYPE_BEACON, (ah->power_level * 2),
                        ieee80211_get_tx_rate(ah->hw, info)->hw_value,
                        1, AR5K_TXKEYIX_INVALID,
                        antenna, flags, 0, 0);
        if (ret)
                goto err_unmap;

        return 0;
err_unmap:
        dma_unmap_single(ah->dev, bf->skbaddr, skb->len, DMA_TO_DEVICE);
        return ret;
}

/*
 * Updates the beacon that is sent by ath5k_beacon_send.  For adhoc,
 * this is called only once at config_bss time, for AP we do it every
 * SWBA interrupt so that the TIM will reflect buffered frames.
 *
 * Called with the beacon lock.
 */
int
ath5k_beacon_update(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
{
        int ret;
        struct ath5k_hw *ah = hw->priv;
        struct ath5k_vif *avf = (void *)vif->drv_priv;
        struct sk_buff *skb;

        if (WARN_ON(!vif)) {
                ret = -EINVAL;
                goto out;
        }

        skb = ieee80211_beacon_get(hw, vif);

        if (!skb) {
                ret = -ENOMEM;
                goto out;
        }

        ath5k_txbuf_free_skb(ah, avf->bbuf);
        avf->bbuf->skb = skb;
        ret = ath5k_beacon_setup(ah, avf->bbuf);
out:
        return ret;
}

/*
 * Transmit a beacon frame at SWBA.  Dynamic updates to the
 * frame contents are done as needed and the slot time is
 * also adjusted based on current state.
 *
 * This is called from software irq context (beacontq tasklets)
 * or user context from ath5k_beacon_config.
 */
static void
ath5k_beacon_send(struct ath5k_hw *ah)
{
        struct ieee80211_vif *vif;
        struct ath5k_vif *avf;
        struct ath5k_buf *bf;
        struct sk_buff *skb;
        int err;

        ATH5K_DBG_UNLIMIT(ah, ATH5K_DEBUG_BEACON, "in beacon_send\n");

        /*
         * Check if the previous beacon has gone out.  If
         * not, don't don't try to post another: skip this
         * period and wait for the next.  Missed beacons
         * indicate a problem and should not occur.  If we
         * miss too many consecutive beacons reset the device.
         */
        if (unlikely(ath5k_hw_num_tx_pending(ah, ah->bhalq) != 0)) {
                ah->bmisscount++;
                ATH5K_DBG(ah, ATH5K_DEBUG_BEACON,
                        "missed %u consecutive beacons\n", ah->bmisscount);
                if (ah->bmisscount > 10) {      /* NB: 10 is a guess */
                        ATH5K_DBG(ah, ATH5K_DEBUG_BEACON,
                                "stuck beacon time (%u missed)\n",
                                ah->bmisscount);
                        ATH5K_DBG(ah, ATH5K_DEBUG_RESET,
                                  "stuck beacon, resetting\n");
                        ieee80211_queue_work(ah->hw, &ah->reset_work);
                }
                return;
        }
        if (unlikely(ah->bmisscount != 0)) {
                ATH5K_DBG(ah, ATH5K_DEBUG_BEACON,
                        "resume beacon xmit after %u misses\n",
                        ah->bmisscount);
                ah->bmisscount = 0;
        }

        if ((ah->opmode == NL80211_IFTYPE_AP && ah->num_ap_vifs > 1) ||
                        ah->opmode == NL80211_IFTYPE_MESH_POINT) {
                u64 tsf = ath5k_hw_get_tsf64(ah);
                u32 tsftu = TSF_TO_TU(tsf);
                int slot = ((tsftu % ah->bintval) * ATH_BCBUF) / ah->bintval;
                vif = ah->bslot[(slot + 1) % ATH_BCBUF];
                ATH5K_DBG(ah, ATH5K_DEBUG_BEACON,
                        "tsf %llx tsftu %x intval %u slot %u vif %p\n",
                        (unsigned long long)tsf, tsftu, ah->bintval, slot, vif);
        } else /* only one interface */
                vif = ah->bslot[0];

        if (!vif)
                return;

        avf = (void *)vif->drv_priv;
        bf = avf->bbuf;

        /*
         * Stop any current dma and put the new frame on the queue.
         * This should never fail since we check above that no frames
         * are still pending on the queue.
         */
        if (unlikely(ath5k_hw_stop_beacon_queue(ah, ah->bhalq))) {
                ATH5K_WARN(ah, "beacon queue %u didn't start/stop ?\n", ah->bhalq);
                /* NB: hw still stops DMA, so proceed */
        }

        /* refresh the beacon for AP or MESH mode */
        if (ah->opmode == NL80211_IFTYPE_AP ||
            ah->opmode == NL80211_IFTYPE_MESH_POINT) {
                err = ath5k_beacon_update(ah->hw, vif);
                if (err)
                        return;
        }

        if (unlikely(bf->skb == NULL || ah->opmode == NL80211_IFTYPE_STATION ||
                     ah->opmode == NL80211_IFTYPE_MONITOR)) {
                ATH5K_WARN(ah, "bf=%p bf_skb=%p\n", bf, bf->skb);
                return;
        }

        trace_ath5k_tx(ah, bf->skb, &ah->txqs[ah->bhalq]);

        ath5k_hw_set_txdp(ah, ah->bhalq, bf->daddr);
        ath5k_hw_start_tx_dma(ah, ah->bhalq);
        ATH5K_DBG(ah, ATH5K_DEBUG_BEACON, "TXDP[%u] = %llx (%p)\n",
                ah->bhalq, (unsigned long long)bf->daddr, bf->desc);

        skb = ieee80211_get_buffered_bc(ah->hw, vif);
        while (skb) {
                ath5k_tx_queue(ah->hw, skb, ah->cabq);

                if (ah->cabq->txq_len >= ah->cabq->txq_max)
                        break;

                skb = ieee80211_get_buffered_bc(ah->hw, vif);
        }

        ah->bsent++;
}

/**
 * ath5k_beacon_update_timers - update beacon timers
 *
 * @ah: struct ath5k_hw pointer we are operating on
 * @bc_tsf: the timestamp of the beacon. 0 to reset the TSF. -1 to perform a
 *          beacon timer update based on the current HW TSF.
 *
 * Calculate the next target beacon transmit time (TBTT) based on the timestamp
 * of a received beacon or the current local hardware TSF and write it to the
 * beacon timer registers.
 *
 * This is called in a variety of situations, e.g. when a beacon is received,
 * when a TSF update has been detected, but also when an new IBSS is created or
 * when we otherwise know we have to update the timers, but we keep it in this
 * function to have it all together in one place.
 */
void
ath5k_beacon_update_timers(struct ath5k_hw *ah, u64 bc_tsf)
{
        u32 nexttbtt, intval, hw_tu, bc_tu;
        u64 hw_tsf;

        intval = ah->bintval & AR5K_BEACON_PERIOD;
        if (ah->opmode == NL80211_IFTYPE_AP && ah->num_ap_vifs > 1) {
                intval /= ATH_BCBUF;    /* staggered multi-bss beacons */
                if (intval < 15)
                        ATH5K_WARN(ah, "intval %u is too low, min 15\n",
                                   intval);
        }
        if (WARN_ON(!intval))
                return;

        /* beacon TSF converted to TU */
        bc_tu = TSF_TO_TU(bc_tsf);

        /* current TSF converted to TU */
        hw_tsf = ath5k_hw_get_tsf64(ah);
        hw_tu = TSF_TO_TU(hw_tsf);

#define FUDGE (AR5K_TUNE_SW_BEACON_RESP + 3)
        /* We use FUDGE to make sure the next TBTT is ahead of the current TU.
         * Since we later subtract AR5K_TUNE_SW_BEACON_RESP (10) in the timer
         * configuration we need to make sure it is bigger than that. */

        if (bc_tsf == -1) {
                /*
                 * no beacons received, called internally.
                 * just need to refresh timers based on HW TSF.
                 */
                nexttbtt = roundup(hw_tu + FUDGE, intval);
        } else if (bc_tsf == 0) {
                /*
                 * no beacon received, probably called by ath5k_reset_tsf().
                 * reset TSF to start with 0.
                 */
                nexttbtt = intval;
                intval |= AR5K_BEACON_RESET_TSF;
        } else if (bc_tsf > hw_tsf) {
                /*
                 * beacon received, SW merge happened but HW TSF not yet updated.
                 * not possible to reconfigure timers yet, but next time we
                 * receive a beacon with the same BSSID, the hardware will
                 * automatically update the TSF and then we need to reconfigure
                 * the timers.
                 */
                ATH5K_DBG_UNLIMIT(ah, ATH5K_DEBUG_BEACON,
                        "need to wait for HW TSF sync\n");
                return;
        } else {
                /*
                 * most important case for beacon synchronization between STA.
                 *
                 * beacon received and HW TSF has been already updated by HW.
                 * update next TBTT based on the TSF of the beacon, but make
                 * sure it is ahead of our local TSF timer.
                 */
                nexttbtt = bc_tu + roundup(hw_tu + FUDGE - bc_tu, intval);
        }
#undef FUDGE

        ah->nexttbtt = nexttbtt;

        intval |= AR5K_BEACON_ENA;
        ath5k_hw_init_beacon_timers(ah, nexttbtt, intval);

        /*
         * debugging output last in order to preserve the time critical aspect
         * of this function
         */
        if (bc_tsf == -1)
                ATH5K_DBG_UNLIMIT(ah, ATH5K_DEBUG_BEACON,
                        "reconfigured timers based on HW TSF\n");
        else if (bc_tsf == 0)
                ATH5K_DBG_UNLIMIT(ah, ATH5K_DEBUG_BEACON,
                        "reset HW TSF and timers\n");
        else
                ATH5K_DBG_UNLIMIT(ah, ATH5K_DEBUG_BEACON,
                        "updated timers based on beacon TSF\n");

        ATH5K_DBG_UNLIMIT(ah, ATH5K_DEBUG_BEACON,
                          "bc_tsf %llx hw_tsf %llx bc_tu %u hw_tu %u nexttbtt %u\n",
                          (unsigned long long) bc_tsf,
                          (unsigned long long) hw_tsf, bc_tu, hw_tu, nexttbtt);
        ATH5K_DBG_UNLIMIT(ah, ATH5K_DEBUG_BEACON, "intval %u %s %s\n",
                intval & AR5K_BEACON_PERIOD,
                intval & AR5K_BEACON_ENA ? "AR5K_BEACON_ENA" : "",
                intval & AR5K_BEACON_RESET_TSF ? "AR5K_BEACON_RESET_TSF" : "");
}

/**
 * ath5k_beacon_config - Configure the beacon queues and interrupts
 *
 * @ah: struct ath5k_hw pointer we are operating on
 *
 * In IBSS mode we use a self-linked tx descriptor if possible. We enable SWBA
 * interrupts to detect TSF updates only.
 */
void
ath5k_beacon_config(struct ath5k_hw *ah)
{
        unsigned long flags;

        spin_lock_irqsave(&ah->block, flags);
        ah->bmisscount = 0;
        ah->imask &= ~(AR5K_INT_BMISS | AR5K_INT_SWBA);

        if (ah->enable_beacon) {
                /*
                 * In IBSS mode we use a self-linked tx descriptor and let the
                 * hardware send the beacons automatically. We have to load it
                 * only once here.
                 * We use the SWBA interrupt only to keep track of the beacon
                 * timers in order to detect automatic TSF updates.
                 */
                ath5k_beaconq_config(ah);

                ah->imask |= AR5K_INT_SWBA;

                if (ah->opmode == NL80211_IFTYPE_ADHOC) {
                        if (ath5k_hw_hasveol(ah))
                                ath5k_beacon_send(ah);
                } else
                        ath5k_beacon_update_timers(ah, -1);
        } else {
                ath5k_hw_stop_beacon_queue(ah, ah->bhalq);
        }

        ath5k_hw_set_imr(ah, ah->imask);
        mmiowb();
        spin_unlock_irqrestore(&ah->block, flags);
}

static void ath5k_tasklet_beacon(unsigned long data)
{
        struct ath5k_hw *ah = (struct ath5k_hw *) data;

        /*
         * Software beacon alert--time to send a beacon.
         *
         * In IBSS mode we use this interrupt just to
         * keep track of the next TBTT (target beacon
         * transmission time) in order to detect whether
         * automatic TSF updates happened.
         */
        if (ah->opmode == NL80211_IFTYPE_ADHOC) {
                /* XXX: only if VEOL supported */
                u64 tsf = ath5k_hw_get_tsf64(ah);
                ah->nexttbtt += ah->bintval;
                ATH5K_DBG(ah, ATH5K_DEBUG_BEACON,
                                "SWBA nexttbtt: %x hw_tu: %x "
                                "TSF: %llx\n",
                                ah->nexttbtt,
                                TSF_TO_TU(tsf),
                                (unsigned long long) tsf);
        } else {
                spin_lock(&ah->block);
                ath5k_beacon_send(ah);
                spin_unlock(&ah->block);
        }
}


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

static void
ath5k_intr_calibration_poll(struct ath5k_hw *ah)
{
        if (time_is_before_eq_jiffies(ah->ah_cal_next_ani) &&
           !(ah->ah_cal_mask & AR5K_CALIBRATION_FULL) &&
           !(ah->ah_cal_mask & AR5K_CALIBRATION_SHORT)) {

                /* Run ANI only when calibration is not active */

                ah->ah_cal_next_ani = jiffies +
                        msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_ANI);
                tasklet_schedule(&ah->ani_tasklet);

        } else if (time_is_before_eq_jiffies(ah->ah_cal_next_short) &&
                !(ah->ah_cal_mask & AR5K_CALIBRATION_FULL) &&
                !(ah->ah_cal_mask & AR5K_CALIBRATION_SHORT)) {

                /* Run calibration only when another calibration
                 * is not running.
                 *
                 * Note: This is for both full/short calibration,
                 * if it's time for a full one, ath5k_calibrate_work will deal
                 * with it. */

                ah->ah_cal_next_short = jiffies +
                        msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_SHORT);
                ieee80211_queue_work(ah->hw, &ah->calib_work);
        }
        /* we could use SWI to generate enough interrupts to meet our
         * calibration interval requirements, if necessary:
         * AR5K_REG_ENABLE_BITS(ah, AR5K_CR, AR5K_CR_SWI); */
}

static void
ath5k_schedule_rx(struct ath5k_hw *ah)
{
        ah->rx_pending = true;
        tasklet_schedule(&ah->rxtq);
}

static void
ath5k_schedule_tx(struct ath5k_hw *ah)
{
        ah->tx_pending = true;
        tasklet_schedule(&ah->txtq);
}

static irqreturn_t
ath5k_intr(int irq, void *dev_id)
{
        struct ath5k_hw *ah = dev_id;
        enum ath5k_int status;
        unsigned int counter = 1000;


        /*
         * If hw is not ready (or detached) and we get an
         * interrupt, or if we have no interrupts pending
         * (that means it's not for us) skip it.
         *
         * NOTE: Group 0/1 PCI interface registers are not
         * supported on WiSOCs, so we can't check for pending
         * interrupts (ISR belongs to another register group
         * so we are ok).
         */
        if (unlikely(test_bit(ATH_STAT_INVALID, ah->status) ||
                        ((ath5k_get_bus_type(ah) != ATH_AHB) &&
                        !ath5k_hw_is_intr_pending(ah))))
                return IRQ_NONE;

        /** Main loop **/
        do {
                ath5k_hw_get_isr(ah, &status);  /* NB: clears IRQ too */

                ATH5K_DBG(ah, ATH5K_DEBUG_INTR, "status 0x%x/0x%x\n",
                                status, ah->imask);

                /*
                 * Fatal hw error -> Log and reset
                 *
                 * Fatal errors are unrecoverable so we have to
                 * reset the card. These errors include bus and
                 * dma errors.
                 */
                if (unlikely(status & AR5K_INT_FATAL)) {

                        ATH5K_DBG(ah, ATH5K_DEBUG_RESET,
                                  "fatal int, resetting\n");
                        ieee80211_queue_work(ah->hw, &ah->reset_work);

                /*
                 * RX Overrun -> Count and reset if needed
                 *
                 * Receive buffers are full. Either the bus is busy or
                 * the CPU is not fast enough to process all received
                 * frames.
                 */
                } else if (unlikely(status & AR5K_INT_RXORN)) {

                        /*
                         * Older chipsets need a reset to come out of this
                         * condition, but we treat it as RX for newer chips.
                         * We don't know exactly which versions need a reset
                         * this guess is copied from the HAL.
                         */
                        ah->stats.rxorn_intr++;

                        if (ah->ah_mac_srev < AR5K_SREV_AR5212) {
                                ATH5K_DBG(ah, ATH5K_DEBUG_RESET,
                                          "rx overrun, resetting\n");
                                ieee80211_queue_work(ah->hw, &ah->reset_work);
                        } else
                                ath5k_schedule_rx(ah);

                } else {

                        /* Software Beacon Alert -> Schedule beacon tasklet */
                        if (status & AR5K_INT_SWBA)
                                tasklet_hi_schedule(&ah->beacontq);

                        /*
                         * No more RX descriptors -> Just count
                         *
                         * NB: the hardware should re-read the link when
                         *     RXE bit is written, but it doesn't work at
                         *     least on older hardware revs.
                         */
                        if (status & AR5K_INT_RXEOL)
                                ah->stats.rxeol_intr++;


                        /* TX Underrun -> Bump tx trigger level */
                        if (status & AR5K_INT_TXURN)
                                ath5k_hw_update_tx_triglevel(ah, true);

                        /* RX -> Schedule rx tasklet */
                        if (status & (AR5K_INT_RXOK | AR5K_INT_RXERR))
                                ath5k_schedule_rx(ah);

                        /* TX -> Schedule tx tasklet */
                        if (status & (AR5K_INT_TXOK
                                        | AR5K_INT_TXDESC
                                        | AR5K_INT_TXERR
                                        | AR5K_INT_TXEOL))
                                ath5k_schedule_tx(ah);

                        /* Missed beacon -> TODO
                        if (status & AR5K_INT_BMISS)
                        */

                        /* MIB event -> Update counters and notify ANI */
                        if (status & AR5K_INT_MIB) {
                                ah->stats.mib_intr++;
                                ath5k_hw_update_mib_counters(ah);
                                ath5k_ani_mib_intr(ah);
                        }

                        /* GPIO -> Notify RFKill layer */
                        if (status & AR5K_INT_GPIO)
                                tasklet_schedule(&ah->rf_kill.toggleq);

                }

                if (ath5k_get_bus_type(ah) == ATH_AHB)
                        break;

        } while (ath5k_hw_is_intr_pending(ah) && --counter > 0);

        /*
         * Until we handle rx/tx interrupts mask them on IMR
         *
         * NOTE: ah->(rx/tx)_pending are set when scheduling the tasklets
         * and unset after we 've handled the interrupts.
         */
        if (ah->rx_pending || ah->tx_pending)
                ath5k_set_current_imask(ah);

        if (unlikely(!counter))
                ATH5K_WARN(ah, "too many interrupts, giving up for now\n");

        /* Fire up calibration poll */
        ath5k_intr_calibration_poll(ah);

        return IRQ_HANDLED;
}

/*
 * Periodically recalibrate the PHY to account
 * for temperature/environment changes.
 */
static void
ath5k_calibrate_work(struct work_struct *work)
{
        struct ath5k_hw *ah = container_of(work, struct ath5k_hw,
                calib_work);

        /* Should we run a full calibration ? */
        if (time_is_before_eq_jiffies(ah->ah_cal_next_full)) {

                ah->ah_cal_next_full = jiffies +
                        msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_FULL);
                ah->ah_cal_mask |= AR5K_CALIBRATION_FULL;

                ATH5K_DBG(ah, ATH5K_DEBUG_CALIBRATE,
                                "running full calibration\n");

                if (ath5k_hw_gainf_calibrate(ah) == AR5K_RFGAIN_NEED_CHANGE) {
                        /*
                         * Rfgain is out of bounds, reset the chip
                         * to load new gain values.
                         */
                        ATH5K_DBG(ah, ATH5K_DEBUG_RESET,
                                        "got new rfgain, resetting\n");
                        ieee80211_queue_work(ah->hw, &ah->reset_work);
                }

                /* TODO: On full calibration we should stop TX here,
                 * so that it doesn't interfere (mostly due to gain_f
                 * calibration that messes with tx packets -see phy.c).
                 *
                 * NOTE: Stopping the queues from above is not enough
                 * to stop TX but saves us from disconecting (at least
                 * we don't lose packets). */
                ieee80211_stop_queues(ah->hw);
        } else
                ah->ah_cal_mask |= AR5K_CALIBRATION_SHORT;


        ATH5K_DBG(ah, ATH5K_DEBUG_CALIBRATE, "channel %u/%x\n",
                ieee80211_frequency_to_channel(ah->curchan->center_freq),
                ah->curchan->hw_value);

        if (ath5k_hw_phy_calibrate(ah, ah->curchan))
                ATH5K_ERR(ah, "calibration of channel %u failed\n",
                        ieee80211_frequency_to_channel(
                                ah->curchan->center_freq));

        /* Clear calibration flags */
        if (ah->ah_cal_mask & AR5K_CALIBRATION_FULL) {
                ieee80211_wake_queues(ah->hw);
                ah->ah_cal_mask &= ~AR5K_CALIBRATION_FULL;
        } else if (ah->ah_cal_mask & AR5K_CALIBRATION_SHORT)
                ah->ah_cal_mask &= ~AR5K_CALIBRATION_SHORT;
}


static void
ath5k_tasklet_ani(unsigned long data)
{
        struct ath5k_hw *ah = (void *)data;

        ah->ah_cal_mask |= AR5K_CALIBRATION_ANI;
        ath5k_ani_calibration(ah);
        ah->ah_cal_mask &= ~AR5K_CALIBRATION_ANI;
}


static void
ath5k_tx_complete_poll_work(struct work_struct *work)
{
        struct ath5k_hw *ah = container_of(work, struct ath5k_hw,
                        tx_complete_work.work);
        struct ath5k_txq *txq;
        int i;
        bool needreset = false;

        mutex_lock(&ah->lock);

        for (i = 0; i < ARRAY_SIZE(ah->txqs); i++) {
                if (ah->txqs[i].setup) {
                        txq = &ah->txqs[i];
                        spin_lock_bh(&txq->lock);
                        if (txq->txq_len > 1) {
                                if (txq->txq_poll_mark) {
                                        ATH5K_DBG(ah, ATH5K_DEBUG_XMIT,
                                                  "TX queue stuck %d\n",
                                                  txq->qnum);
                                        needreset = true;
                                        txq->txq_stuck++;
                                        spin_unlock_bh(&txq->lock);
                                        break;
                                } else {
                                        txq->txq_poll_mark = true;
                                }
                        }
                        spin_unlock_bh(&txq->lock);
                }
        }

        if (needreset) {
                ATH5K_DBG(ah, ATH5K_DEBUG_RESET,
                          "TX queues stuck, resetting\n");
                ath5k_reset(ah, NULL, true);
        }

        mutex_unlock(&ah->lock);

        ieee80211_queue_delayed_work(ah->hw, &ah->tx_complete_work,
                msecs_to_jiffies(ATH5K_TX_COMPLETE_POLL_INT));
}


/*************************\
* Initialization routines *
\*************************/

int __devinit
ath5k_init_ah(struct ath5k_hw *ah, const struct ath_bus_ops *bus_ops)
{
        struct ieee80211_hw *hw = ah->hw;
        struct ath_common *common;
        int ret;
        int csz;

        /* Initialize driver private data */
        SET_IEEE80211_DEV(hw, ah->dev);
        hw->flags = IEEE80211_HW_RX_INCLUDES_FCS |
                        IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING |
                        IEEE80211_HW_SIGNAL_DBM |
                        IEEE80211_HW_REPORTS_TX_ACK_STATUS;

        hw->wiphy->interface_modes =
                BIT(NL80211_IFTYPE_AP) |
                BIT(NL80211_IFTYPE_STATION) |
                BIT(NL80211_IFTYPE_ADHOC) |
                BIT(NL80211_IFTYPE_MESH_POINT);

        /* both antennas can be configured as RX or TX */
        hw->wiphy->available_antennas_tx = 0x3;
        hw->wiphy->available_antennas_rx = 0x3;

        hw->extra_tx_headroom = 2;
        hw->channel_change_time = 5000;

        /*
         * Mark the device as detached to avoid processing
         * interrupts until setup is complete.
         */
        __set_bit(ATH_STAT_INVALID, ah->status);

        ah->opmode = NL80211_IFTYPE_STATION;
        ah->bintval = 1000;
        mutex_init(&ah->lock);
        spin_lock_init(&ah->rxbuflock);
        spin_lock_init(&ah->txbuflock);
        spin_lock_init(&ah->block);
        spin_lock_init(&ah->irqlock);

        /* Setup interrupt handler */
        ret = request_irq(ah->irq, ath5k_intr, IRQF_SHARED, "ath", ah);
        if (ret) {
                ATH5K_ERR(ah, "request_irq failed\n");
                goto err;
        }

        common = ath5k_hw_common(ah);
        common->ops = &ath5k_common_ops;
        common->bus_ops = bus_ops;
        common->ah = ah;
        common->hw = hw;
        common->priv = ah;
        common->clockrate = 40;

        /*
         * Cache line size is used to size and align various
         * structures used to communicate with the hardware.
         */
        ath5k_read_cachesize(common, &csz);
        common->cachelsz = csz << 2; /* convert to bytes */

        spin_lock_init(&common->cc_lock);

        /* Initialize device */
        ret = ath5k_hw_init(ah);
        if (ret)
                goto err_irq;

        /* Set up multi-rate retry capabilities */
        if (ah->ah_capabilities.cap_has_mrr_support) {
                hw->max_rates = 4;
                hw->max_rate_tries = max(AR5K_INIT_RETRY_SHORT,
                                         AR5K_INIT_RETRY_LONG);
        }

        hw->vif_data_size = sizeof(struct ath5k_vif);

        /* Finish private driver data initialization */
        ret = ath5k_init(hw);
        if (ret)
                goto err_ah;

        ATH5K_INFO(ah, "Atheros AR%s chip found (MAC: 0x%x, PHY: 0x%x)\n",
                        ath5k_chip_name(AR5K_VERSION_MAC, ah->ah_mac_srev),
                                        ah->ah_mac_srev,
                                        ah->ah_phy_revision);

        if (!ah->ah_single_chip) {
                /* Single chip radio (!RF5111) */
                if (ah->ah_radio_5ghz_revision &&
                        !ah->ah_radio_2ghz_revision) {
                        /* No 5GHz support -> report 2GHz radio */
                        if (!test_bit(AR5K_MODE_11A,
                                ah->ah_capabilities.cap_mode)) {
                                ATH5K_INFO(ah, "RF%s 2GHz radio found (0x%x)\n",
                                        ath5k_chip_name(AR5K_VERSION_RAD,
                                                ah->ah_radio_5ghz_revision),
                                                ah->ah_radio_5ghz_revision);
                        /* No 2GHz support (5110 and some
                         * 5GHz only cards) -> report 5GHz radio */
                        } else if (!test_bit(AR5K_MODE_11B,
                                ah->ah_capabilities.cap_mode)) {
                                ATH5K_INFO(ah, "RF%s 5GHz radio found (0x%x)\n",
                                        ath5k_chip_name(AR5K_VERSION_RAD,
                                                ah->ah_radio_5ghz_revision),
                                                ah->ah_radio_5ghz_revision);
                        /* Multiband radio */
                        } else {
                                ATH5K_INFO(ah, "RF%s multiband radio found"
                                        " (0x%x)\n",
                                        ath5k_chip_name(AR5K_VERSION_RAD,
                                                ah->ah_radio_5ghz_revision),
                                                ah->ah_radio_5ghz_revision);
                        }
                }
                /* Multi chip radio (RF5111 - RF2111) ->
                 * report both 2GHz/5GHz radios */
                else if (ah->ah_radio_5ghz_revision &&
                                ah->ah_radio_2ghz_revision) {
                        ATH5K_INFO(ah, "RF%s 5GHz radio found (0x%x)\n",
                                ath5k_chip_name(AR5K_VERSION_RAD,
                                        ah->ah_radio_5ghz_revision),
                                        ah->ah_radio_5ghz_revision);
                        ATH5K_INFO(ah, "RF%s 2GHz radio found (0x%x)\n",
                                ath5k_chip_name(AR5K_VERSION_RAD,
                                        ah->ah_radio_2ghz_revision),
                                        ah->ah_radio_2ghz_revision);
                }
        }

        ath5k_debug_init_device(ah);

        /* ready to process interrupts */
        __clear_bit(ATH_STAT_INVALID, ah->status);

        return 0;
err_ah:
        ath5k_hw_deinit(ah);
err_irq:
        free_irq(ah->irq, ah);
err:
        return ret;
}

static int
ath5k_stop_locked(struct ath5k_hw *ah)
{

        ATH5K_DBG(ah, ATH5K_DEBUG_RESET, "invalid %u\n",
                        test_bit(ATH_STAT_INVALID, ah->status));

        /*
         * 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).
         */
        ieee80211_stop_queues(ah->hw);

        if (!test_bit(ATH_STAT_INVALID, ah->status)) {
                ath5k_led_off(ah);
                ath5k_hw_set_imr(ah, 0);
                synchronize_irq(ah->irq);
                ath5k_rx_stop(ah);
                ath5k_hw_dma_stop(ah);
                ath5k_drain_tx_buffs(ah);
                ath5k_hw_phy_disable(ah);
        }

        return 0;
}

int ath5k_start(struct ieee80211_hw *hw)
{
        struct ath5k_hw *ah = hw->priv;
        struct ath_common *common = ath5k_hw_common(ah);
        int ret, i;

        mutex_lock(&ah->lock);

        ATH5K_DBG(ah, ATH5K_DEBUG_RESET, "mode %d\n", ah->opmode);

        /*
         * Stop anything previously setup.  This is safe
         * no matter this is the first time through or not.
         */
        ath5k_stop_locked(ah);

        /*
         * 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.
         */
        ah->curchan = ah->hw->conf.channel;
        ah->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
                | AR5K_INT_MIB;

        ret = ath5k_reset(ah, NULL, false);
        if (ret)
                goto done;

        if (!ath5k_modparam_no_hw_rfkill_switch)
                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 < common->keymax; i++)
                ath_hw_keyreset(common, (u16) i);

        /* Use higher rates for acks instead of base
         * rate */
        ah->ah_ack_bitrate_high = true;

        for (i = 0; i < ARRAY_SIZE(ah->bslot); i++)
                ah->bslot[i] = NULL;

        ret = 0;
done:
        mmiowb();
        mutex_unlock(&ah->lock);

        ieee80211_queue_delayed_work(ah->hw, &ah->tx_complete_work,
                        msecs_to_jiffies(ATH5K_TX_COMPLETE_POLL_INT));

        return ret;
}

static void ath5k_stop_tasklets(struct ath5k_hw *ah)
{
        ah->rx_pending = false;
        ah->tx_pending = false;
        tasklet_kill(&ah->rxtq);
        tasklet_kill(&ah->txtq);
        tasklet_kill(&ah->beacontq);
        tasklet_kill(&ah->ani_tasklet);
}

/*
 * Stop the device, grabbing the top-level lock to protect
 * against concurrent entry through ath5k_init (which can happen
 * if another thread does a system call and the thread doing the
 * stop is preempted).
 */
void ath5k_stop(struct ieee80211_hw *hw)
{
        struct ath5k_hw *ah = hw->priv;
        int ret;

        mutex_lock(&ah->lock);
        ret = ath5k_stop_locked(ah);
        if (ret == 0 && !test_bit(ATH_STAT_INVALID, ah->status)) {
                /*
                 * Don't set the card in full sleep mode!
                 *
                 * a) When the device is in this state it must be carefully
                 * woken up or references to registers in the PCI clock
                 * domain may freeze the bus (and system).  This varies
                 * by chip and is mostly an issue with newer parts
                 * (madwifi sources mentioned srev >= 0x78) that go to
                 * sleep more quickly.
                 *
                 * b) On older chips full sleep results a weird behaviour
                 * during wakeup. I tested various cards with srev < 0x78
                 * and they don't wake up after module reload, a second
                 * module reload is needed to bring the card up again.
                 *
                 * Until we figure out what's going on don't enable
                 * full chip reset on any chip (this is what Legacy HAL
                 * and Sam's HAL do anyway). Instead Perform a full reset
                 * on the device (same as initial state after attach) and
                 * leave it idle (keep MAC/BB on warm reset) */
                ret = ath5k_hw_on_hold(ah);

                ATH5K_DBG(ah, ATH5K_DEBUG_RESET,
                                "putting device to sleep\n");
        }

        mmiowb();
        mutex_unlock(&ah->lock);

        ath5k_stop_tasklets(ah);

        cancel_delayed_work_sync(&ah->tx_complete_work);

        if (!ath5k_modparam_no_hw_rfkill_switch)
                ath5k_rfkill_hw_stop(ah);
}

/*
 * Reset the hardware.  If chan is not NULL, then also pause rx/tx
 * and change to the given channel.
 *
 * This should be called with ah->lock.
 */
static int
ath5k_reset(struct ath5k_hw *ah, struct ieee80211_channel *chan,
                                                        bool skip_pcu)
{
        struct ath_common *common = ath5k_hw_common(ah);
        int ret, ani_mode;
        bool fast;

        ATH5K_DBG(ah, ATH5K_DEBUG_RESET, "resetting\n");

        ath5k_hw_set_imr(ah, 0);
        synchronize_irq(ah->irq);
        ath5k_stop_tasklets(ah);

        /* Save ani mode and disable ANI during
         * reset. If we don't we might get false
         * PHY error interrupts. */
        ani_mode = ah->ani_state.ani_mode;
        ath5k_ani_init(ah, ATH5K_ANI_MODE_OFF);

        /* We are going to empty hw queues
         * so we should also free any remaining
         * tx buffers */
        ath5k_drain_tx_buffs(ah);
        if (chan)
                ah->curchan = chan;

        fast = ((chan != NULL) && modparam_fastchanswitch) ? 1 : 0;

        ret = ath5k_hw_reset(ah, ah->opmode, ah->curchan, fast, skip_pcu);
        if (ret) {
                ATH5K_ERR(ah, "can't reset hardware (%d)\n", ret);
                goto err;
        }

        ret = ath5k_rx_start(ah);
        if (ret) {
                ATH5K_ERR(ah, "can't start recv logic\n");
                goto err;
        }

        ath5k_ani_init(ah, ani_mode);

        /*
         * Set calibration intervals
         *
         * Note: We don't need to run calibration imediately
         * since some initial calibration is done on reset
         * even for fast channel switching. Also on scanning
         * this will get set again and again and it won't get
         * executed unless we connect somewhere and spend some
         * time on the channel (that's what calibration needs
         * anyway to be accurate).
         */
        ah->ah_cal_next_full = jiffies +
                msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_FULL);
        ah->ah_cal_next_ani = jiffies +
                msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_ANI);
        ah->ah_cal_next_short = jiffies +
                msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_SHORT);

        ewma_init(&ah->ah_beacon_rssi_avg, 1024, 8);

        /* clear survey data and cycle counters */
        memset(&ah->survey, 0, sizeof(ah->survey));
        spin_lock_bh(&common->cc_lock);
        ath_hw_cycle_counters_update(common);
        memset(&common->cc_survey, 0, sizeof(common->cc_survey));
        memset(&common->cc_ani, 0, sizeof(common->cc_ani));
        spin_unlock_bh(&common->cc_lock);

        /*
         * 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(ah, c); */

        ath5k_beacon_config(ah);
        /* intrs are enabled by ath5k_beacon_config */

        ieee80211_wake_queues(ah->hw);

        return 0;
err:
        return ret;
}

static void ath5k_reset_work(struct work_struct *work)
{
        struct ath5k_hw *ah = container_of(work, struct ath5k_hw,
                reset_work);

        mutex_lock(&ah->lock);
        ath5k_reset(ah, NULL, true);
        mutex_unlock(&ah->lock);
}

static int __devinit
ath5k_init(struct ieee80211_hw *hw)
{

        struct ath5k_hw *ah = hw->priv;
        struct ath_regulatory *regulatory = ath5k_hw_regulatory(ah);
        struct ath5k_txq *txq;
        u8 mac[ETH_ALEN] = {};
        int ret;


        /*
         * Collect the channel list.  The 802.11 layer
         * is responsible for filtering this list based
         * on settings like the phy mode and regulatory
         * domain restrictions.
         */
        ret = ath5k_setup_bands(hw);
        if (ret) {
                ATH5K_ERR(ah, "can't get channels\n");
                goto err;
        }

        /*
         * Allocate tx+rx descriptors and populate the lists.
         */
        ret = ath5k_desc_alloc(ah);
        if (ret) {
                ATH5K_ERR(ah, "can't allocate descriptors\n");
                goto err;
        }

        /*
         * Allocate hardware transmit queues: one queue for
         * beacon frames and one data queue for each QoS
         * priority.  Note that hw functions handle resetting
         * these queues at the needed time.
         */
        ret = ath5k_beaconq_setup(ah);
        if (ret < 0) {
                ATH5K_ERR(ah, "can't setup a beacon xmit queue\n");
                goto err_desc;
        }
        ah->bhalq = ret;
        ah->cabq = ath5k_txq_setup(ah, AR5K_TX_QUEUE_CAB, 0);
        if (IS_ERR(ah->cabq)) {
                ATH5K_ERR(ah, "can't setup cab queue\n");
                ret = PTR_ERR(ah->cabq);
                goto err_bhal;
        }

        /* 5211 and 5212 usually support 10 queues but we better rely on the
         * capability information */
        if (ah->ah_capabilities.cap_queues.q_tx_num >= 6) {
                /* This order matches mac80211's queue priority, so we can
                * directly use the mac80211 queue number without any mapping */
                txq = ath5k_txq_setup(ah, AR5K_TX_QUEUE_DATA, AR5K_WME_AC_VO);
                if (IS_ERR(txq)) {
                        ATH5K_ERR(ah, "can't setup xmit queue\n");
                        ret = PTR_ERR(txq);
                        goto err_queues;
                }
                txq = ath5k_txq_setup(ah, AR5K_TX_QUEUE_DATA, AR5K_WME_AC_VI);
                if (IS_ERR(txq)) {
                        ATH5K_ERR(ah, "can't setup xmit queue\n");
                        ret = PTR_ERR(txq);
                        goto err_queues;
                }
                txq = ath5k_txq_setup(ah, AR5K_TX_QUEUE_DATA, AR5K_WME_AC_BE);
                if (IS_ERR(txq)) {
                        ATH5K_ERR(ah, "can't setup xmit queue\n");
                        ret = PTR_ERR(txq);
                        goto err_queues;
                }
                txq = ath5k_txq_setup(ah, AR5K_TX_QUEUE_DATA, AR5K_WME_AC_BK);
                if (IS_ERR(txq)) {
                        ATH5K_ERR(ah, "can't setup xmit queue\n");
                        ret = PTR_ERR(txq);
                        goto err_queues;
                }
                hw->queues = 4;
        } else {
                /* older hardware (5210) can only support one data queue */
                txq = ath5k_txq_setup(ah, AR5K_TX_QUEUE_DATA, AR5K_WME_AC_BE);
                if (IS_ERR(txq)) {
                        ATH5K_ERR(ah, "can't setup xmit queue\n");
                        ret = PTR_ERR(txq);
                        goto err_queues;
                }
                hw->queues = 1;
        }

        tasklet_init(&ah->rxtq, ath5k_tasklet_rx, (unsigned long)ah);
        tasklet_init(&ah->txtq, ath5k_tasklet_tx, (unsigned long)ah);
        tasklet_init(&ah->beacontq, ath5k_tasklet_beacon, (unsigned long)ah);
        tasklet_init(&ah->ani_tasklet, ath5k_tasklet_ani, (unsigned long)ah);

        INIT_WORK(&ah->reset_work, ath5k_reset_work);
        INIT_WORK(&ah->calib_work, ath5k_calibrate_work);
        INIT_DELAYED_WORK(&ah->tx_complete_work, ath5k_tx_complete_poll_work);

        ret = ath5k_hw_common(ah)->bus_ops->eeprom_read_mac(ah, mac);
        if (ret) {
                ATH5K_ERR(ah, "unable to read address from EEPROM\n");
                goto err_queues;
        }

        SET_IEEE80211_PERM_ADDR(hw, mac);
        /* All MAC address bits matter for ACKs */
        ath5k_update_bssid_mask_and_opmode(ah, NULL);

        regulatory->current_rd = ah->ah_capabilities.cap_eeprom.ee_regdomain;
        ret = ath_regd_init(regulatory, hw->wiphy, ath5k_reg_notifier);
        if (ret) {
                ATH5K_ERR(ah, "can't initialize regulatory system\n");
                goto err_queues;
        }

        ret = ieee80211_register_hw(hw);
        if (ret) {
                ATH5K_ERR(ah, "can't register ieee80211 hw\n");
                goto err_queues;
        }

        if (!ath_is_world_regd(regulatory))
                regulatory_hint(hw->wiphy, regulatory->alpha2);

        ath5k_init_leds(ah);

        ath5k_sysfs_register(ah);

        return 0;
err_queues:
        ath5k_txq_release(ah);
err_bhal:
        ath5k_hw_release_tx_queue(ah, ah->bhalq);
err_desc:
        ath5k_desc_free(ah);
err:
        return ret;
}

void
ath5k_deinit_ah(struct ath5k_hw *ah)
{
        struct ieee80211_hw *hw = ah->hw;

        /*
         * NB: the order of these is important:
         * o call the 802.11 layer before detaching ath5k_hw to
         *   ensure callbacks into the driver to delete global
         *   key cache entries can be handled
         * o reclaim the tx queue data structures after calling
         *   the 802.11 layer as we'll get called back to reclaim
         *   node state and potentially want to use them
         * o to cleanup the tx queues the hal is called, so detach
         *   it last
         * XXX: ??? detach ath5k_hw ???
         * Other than that, it's straightforward...
         */
        ieee80211_unregister_hw(hw);
        ath5k_desc_free(ah);
        ath5k_txq_release(ah);
        ath5k_hw_release_tx_queue(ah, ah->bhalq);
        ath5k_unregister_leds(ah);

        ath5k_sysfs_unregister(ah);
        /*
         * NB: can't reclaim these until after ieee80211_ifdetach
         * returns because we'll get called back to reclaim node
         * state and potentially want to use them.
         */
        ath5k_hw_deinit(ah);
        free_irq(ah->irq, ah);
}

bool
ath5k_any_vif_assoc(struct ath5k_hw *ah)
{
        struct ath5k_vif_iter_data iter_data;
        iter_data.hw_macaddr = NULL;
        iter_data.any_assoc = false;
        iter_data.need_set_hw_addr = false;
        iter_data.found_active = true;

        ieee80211_iterate_active_interfaces_atomic(ah->hw, ath5k_vif_iter,
                                                   &iter_data);
        return iter_data.any_assoc;
}

void
ath5k_set_beacon_filter(struct ieee80211_hw *hw, bool enable)
{
        struct ath5k_hw *ah = hw->priv;
        u32 rfilt;
        rfilt = ath5k_hw_get_rx_filter(ah);
        if (enable)
                rfilt |= AR5K_RX_FILTER_BEACON;
        else
                rfilt &= ~AR5K_RX_FILTER_BEACON;
        ath5k_hw_set_rx_filter(ah, rfilt);
        ah->filter_flags = rfilt;
}