/*
 * Atheros CARL9170 driver
 *
 * mac80211 interaction code
 *
 * Copyright 2008, Johannes Berg <johannes@sipsolutions.net>
 * Copyright 2009, 2010, Christian Lamparter <chunkeey@googlemail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, see
 * http://www.gnu.org/licenses/.
 *
 * This file incorporates work covered by the following copyright and
 * permission notice:
 *    Copyright (c) 2007-2008 Atheros Communications, Inc.
 *
 *    Permission to use, copy, modify, and/or distribute this software for any
 *    purpose with or without fee is hereby granted, provided that the above
 *    copyright notice and this permission notice appear in all copies.
 *
 *    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *    ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/etherdevice.h>
#include <linux/random.h>
#include <net/mac80211.h>
#include <net/cfg80211.h>
#include "hw.h"
#include "carl9170.h"
#include "cmd.h"

static bool modparam_nohwcrypt;
module_param_named(nohwcrypt, modparam_nohwcrypt, bool, 0444);
MODULE_PARM_DESC(nohwcrypt, "Disable hardware crypto offload.");

int modparam_noht;
module_param_named(noht, modparam_noht, int, 0444);
MODULE_PARM_DESC(noht, "Disable MPDU aggregation.");

#define RATE(_bitrate, _hw_rate, _txpidx, _flags) {     \
        .bitrate        = (_bitrate),                   \
        .flags          = (_flags),                     \
        .hw_value       = (_hw_rate) | (_txpidx) << 4,  \
}

struct ieee80211_rate __carl9170_ratetable[] = {
        RATE(10, 0, 0, 0),
        RATE(20, 1, 1, IEEE80211_RATE_SHORT_PREAMBLE),
        RATE(55, 2, 2, IEEE80211_RATE_SHORT_PREAMBLE),
        RATE(110, 3, 3, IEEE80211_RATE_SHORT_PREAMBLE),
        RATE(60, 0xb, 0, 0),
        RATE(90, 0xf, 0, 0),
        RATE(120, 0xa, 0, 0),
        RATE(180, 0xe, 0, 0),
        RATE(240, 0x9, 0, 0),
        RATE(360, 0xd, 1, 0),
        RATE(480, 0x8, 2, 0),
        RATE(540, 0xc, 3, 0),
};
#undef RATE

#define carl9170_g_ratetable    (__carl9170_ratetable + 0)
#define carl9170_g_ratetable_size       12
#define carl9170_a_ratetable    (__carl9170_ratetable + 4)
#define carl9170_a_ratetable_size       8

/*
 * NB: The hw_value is used as an index into the carl9170_phy_freq_params
 *     array in phy.c so that we don't have to do frequency lookups!
 */
#define CHAN(_freq, _idx) {             \
        .center_freq    = (_freq),      \
        .hw_value       = (_idx),       \
        .max_power      = 18, /* XXX */ \
}

static struct ieee80211_channel carl9170_2ghz_chantable[] = {
        CHAN(2412,  0),
        CHAN(2417,  1),
        CHAN(2422,  2),
        CHAN(2427,  3),
        CHAN(2432,  4),
        CHAN(2437,  5),
        CHAN(2442,  6),
        CHAN(2447,  7),
        CHAN(2452,  8),
        CHAN(2457,  9),
        CHAN(2462, 10),
        CHAN(2467, 11),
        CHAN(2472, 12),
        CHAN(2484, 13),
};

static struct ieee80211_channel carl9170_5ghz_chantable[] = {
        CHAN(4920, 14),
        CHAN(4940, 15),
        CHAN(4960, 16),
        CHAN(4980, 17),
        CHAN(5040, 18),
        CHAN(5060, 19),
        CHAN(5080, 20),
        CHAN(5180, 21),
        CHAN(5200, 22),
        CHAN(5220, 23),
        CHAN(5240, 24),
        CHAN(5260, 25),
        CHAN(5280, 26),
        CHAN(5300, 27),
        CHAN(5320, 28),
        CHAN(5500, 29),
        CHAN(5520, 30),
        CHAN(5540, 31),
        CHAN(5560, 32),
        CHAN(5580, 33),
        CHAN(5600, 34),
        CHAN(5620, 35),
        CHAN(5640, 36),
        CHAN(5660, 37),
        CHAN(5680, 38),
        CHAN(5700, 39),
        CHAN(5745, 40),
        CHAN(5765, 41),
        CHAN(5785, 42),
        CHAN(5805, 43),
        CHAN(5825, 44),
        CHAN(5170, 45),
        CHAN(5190, 46),
        CHAN(5210, 47),
        CHAN(5230, 48),
};
#undef CHAN

#define CARL9170_HT_CAP                                                 \
{                                                                       \
        .ht_supported   = true,                                         \
        .cap            = IEEE80211_HT_CAP_MAX_AMSDU |                  \
                          IEEE80211_HT_CAP_SUP_WIDTH_20_40 |            \
                          IEEE80211_HT_CAP_SGI_40 |                     \
                          IEEE80211_HT_CAP_DSSSCCK40 |                  \
                          IEEE80211_HT_CAP_SM_PS,                       \
        .ampdu_factor   = IEEE80211_HT_MAX_AMPDU_64K,                   \
        .ampdu_density  = IEEE80211_HT_MPDU_DENSITY_8,                  \
        .mcs            = {                                             \
                .rx_mask = { 0xff, 0xff, 0, 0, 0x1, 0, 0, 0, 0, 0, },   \
                .rx_highest = cpu_to_le16(300),                         \
                .tx_params = IEEE80211_HT_MCS_TX_DEFINED,               \
        },                                                              \
}

static struct ieee80211_supported_band carl9170_band_2GHz = {
        .channels       = carl9170_2ghz_chantable,
        .n_channels     = ARRAY_SIZE(carl9170_2ghz_chantable),
        .bitrates       = carl9170_g_ratetable,
        .n_bitrates     = carl9170_g_ratetable_size,
        .ht_cap         = CARL9170_HT_CAP,
};

static struct ieee80211_supported_band carl9170_band_5GHz = {
        .channels       = carl9170_5ghz_chantable,
        .n_channels     = ARRAY_SIZE(carl9170_5ghz_chantable),
        .bitrates       = carl9170_a_ratetable,
        .n_bitrates     = carl9170_a_ratetable_size,
        .ht_cap         = CARL9170_HT_CAP,
};

static void carl9170_ampdu_gc(struct ar9170 *ar)
{
        struct carl9170_sta_tid *tid_info;
        LIST_HEAD(tid_gc);

        rcu_read_lock();
        list_for_each_entry_rcu(tid_info, &ar->tx_ampdu_list, list) {
                spin_lock_bh(&ar->tx_ampdu_list_lock);
                if (tid_info->state == CARL9170_TID_STATE_SHUTDOWN) {
                        tid_info->state = CARL9170_TID_STATE_KILLED;
                        list_del_rcu(&tid_info->list);
                        ar->tx_ampdu_list_len--;
                        list_add_tail(&tid_info->tmp_list, &tid_gc);
                }
                spin_unlock_bh(&ar->tx_ampdu_list_lock);

        }
        rcu_assign_pointer(ar->tx_ampdu_iter, tid_info);
        rcu_read_unlock();

        synchronize_rcu();

        while (!list_empty(&tid_gc)) {
                struct sk_buff *skb;
                tid_info = list_first_entry(&tid_gc, struct carl9170_sta_tid,
                                            tmp_list);

                while ((skb = __skb_dequeue(&tid_info->queue)))
                        carl9170_tx_status(ar, skb, false);

                list_del_init(&tid_info->tmp_list);
                kfree(tid_info);
        }
}

static void carl9170_flush(struct ar9170 *ar, bool drop_queued)
{
        if (drop_queued) {
                int i;

                /*
                 * We can only drop frames which have not been uploaded
                 * to the device yet.
                 */

                for (i = 0; i < ar->hw->queues; i++) {
                        struct sk_buff *skb;

                        while ((skb = skb_dequeue(&ar->tx_pending[i]))) {
                                struct ieee80211_tx_info *info;

                                info = IEEE80211_SKB_CB(skb);
                                if (info->flags & IEEE80211_TX_CTL_AMPDU)
                                        atomic_dec(&ar->tx_ampdu_upload);

                                carl9170_tx_status(ar, skb, false);
                        }
                }
        }

        /* Wait for all other outstanding frames to timeout. */
        if (atomic_read(&ar->tx_total_queued))
                WARN_ON(wait_for_completion_timeout(&ar->tx_flush, HZ) == 0);
}

static void carl9170_flush_ba(struct ar9170 *ar)
{
        struct sk_buff_head free;
        struct carl9170_sta_tid *tid_info;
        struct sk_buff *skb;

        __skb_queue_head_init(&free);

        rcu_read_lock();
        spin_lock_bh(&ar->tx_ampdu_list_lock);
        list_for_each_entry_rcu(tid_info, &ar->tx_ampdu_list, list) {
                if (tid_info->state > CARL9170_TID_STATE_SUSPEND) {
                        tid_info->state = CARL9170_TID_STATE_SUSPEND;

                        spin_lock(&tid_info->lock);
                        while ((skb = __skb_dequeue(&tid_info->queue)))
                                __skb_queue_tail(&free, skb);
                        spin_unlock(&tid_info->lock);
                }
        }
        spin_unlock_bh(&ar->tx_ampdu_list_lock);
        rcu_read_unlock();

        while ((skb = __skb_dequeue(&free)))
                carl9170_tx_status(ar, skb, false);
}

static void carl9170_zap_queues(struct ar9170 *ar)
{
        struct carl9170_vif_info *cvif;
        unsigned int i;

        carl9170_ampdu_gc(ar);

        carl9170_flush_ba(ar);
        carl9170_flush(ar, true);

        for (i = 0; i < ar->hw->queues; i++) {
                spin_lock_bh(&ar->tx_status[i].lock);
                while (!skb_queue_empty(&ar->tx_status[i])) {
                        struct sk_buff *skb;

                        skb = skb_peek(&ar->tx_status[i]);
                        carl9170_tx_get_skb(skb);
                        spin_unlock_bh(&ar->tx_status[i].lock);
                        carl9170_tx_drop(ar, skb);
                        spin_lock_bh(&ar->tx_status[i].lock);
                        carl9170_tx_put_skb(skb);
                }
                spin_unlock_bh(&ar->tx_status[i].lock);
        }

        BUILD_BUG_ON(CARL9170_NUM_TX_LIMIT_SOFT < 1);
        BUILD_BUG_ON(CARL9170_NUM_TX_LIMIT_HARD < CARL9170_NUM_TX_LIMIT_SOFT);
        BUILD_BUG_ON(CARL9170_NUM_TX_LIMIT_HARD >= CARL9170_BAW_BITS);

        /* reinitialize queues statistics */
        memset(&ar->tx_stats, 0, sizeof(ar->tx_stats));
        for (i = 0; i < ar->hw->queues; i++)
                ar->tx_stats[i].limit = CARL9170_NUM_TX_LIMIT_HARD;

        for (i = 0; i < DIV_ROUND_UP(ar->fw.mem_blocks, BITS_PER_LONG); i++)
                ar->mem_bitmap[i] = 0;

        rcu_read_lock();
        list_for_each_entry_rcu(cvif, &ar->vif_list, list) {
                spin_lock_bh(&ar->beacon_lock);
                dev_kfree_skb_any(cvif->beacon);
                cvif->beacon = NULL;
                spin_unlock_bh(&ar->beacon_lock);
        }
        rcu_read_unlock();

        atomic_set(&ar->tx_ampdu_upload, 0);
        atomic_set(&ar->tx_ampdu_scheduler, 0);
        atomic_set(&ar->tx_total_pending, 0);
        atomic_set(&ar->tx_total_queued, 0);
        atomic_set(&ar->mem_free_blocks, ar->fw.mem_blocks);
}

#define CARL9170_FILL_QUEUE(queue, ai_fs, cwmin, cwmax, _txop)          \
do {                                                                    \
        queue.aifs = ai_fs;                                             \
        queue.cw_min = cwmin;                                           \
        queue.cw_max = cwmax;                                           \
        queue.txop = _txop;                                             \
} while (0)

static int carl9170_op_start(struct ieee80211_hw *hw)
{
        struct ar9170 *ar = hw->priv;
        int err, i;

        mutex_lock(&ar->mutex);

        carl9170_zap_queues(ar);

        /* reset QoS defaults */
        CARL9170_FILL_QUEUE(ar->edcf[AR9170_TXQ_VO], 2, 3,     7, 47);
        CARL9170_FILL_QUEUE(ar->edcf[AR9170_TXQ_VI], 2, 7,    15, 94);
        CARL9170_FILL_QUEUE(ar->edcf[AR9170_TXQ_BE], 3, 15, 1023,  0);
        CARL9170_FILL_QUEUE(ar->edcf[AR9170_TXQ_BK], 7, 15, 1023,  0);
        CARL9170_FILL_QUEUE(ar->edcf[AR9170_TXQ_SPECIAL], 2, 3, 7, 0);

        ar->current_factor = ar->current_density = -1;
        /* "The first key is unique." */
        ar->usedkeys = 1;
        ar->filter_state = 0;
        ar->ps.last_action = jiffies;
        ar->ps.last_slept = jiffies;
        ar->erp_mode = CARL9170_ERP_AUTO;

        /* Set "disable hw crypto offload" whenever the module parameter
         * nohwcrypt is true or if the firmware does not support it.
         */
        ar->disable_offload = modparam_nohwcrypt |
                ar->fw.disable_offload_fw;
        ar->rx_software_decryption = ar->disable_offload;

        for (i = 0; i < ar->hw->queues; i++) {
                ar->queue_stop_timeout[i] = jiffies;
                ar->max_queue_stop_timeout[i] = 0;
        }

        atomic_set(&ar->mem_allocs, 0);

        err = carl9170_usb_open(ar);
        if (err)
                goto out;

        err = carl9170_init_mac(ar);
        if (err)
                goto out;

        err = carl9170_set_qos(ar);
        if (err)
                goto out;

        if (ar->fw.rx_filter) {
                err = carl9170_rx_filter(ar, CARL9170_RX_FILTER_OTHER_RA |
                        CARL9170_RX_FILTER_CTL_OTHER | CARL9170_RX_FILTER_BAD);
                if (err)
                        goto out;
        }

        err = carl9170_write_reg(ar, AR9170_MAC_REG_DMA_TRIGGER,
                                 AR9170_DMA_TRIGGER_RXQ);
        if (err)
                goto out;

        /* Clear key-cache */
        for (i = 0; i < AR9170_CAM_MAX_USER + 4; i++) {
                err = carl9170_upload_key(ar, i, NULL, AR9170_ENC_ALG_NONE,
                                          0, NULL, 0);
                if (err)
                        goto out;

                err = carl9170_upload_key(ar, i, NULL, AR9170_ENC_ALG_NONE,
                                          1, NULL, 0);
                if (err)
                        goto out;

                if (i < AR9170_CAM_MAX_USER) {
                        err = carl9170_disable_key(ar, i);
                        if (err)
                                goto out;
                }
        }

        carl9170_set_state_when(ar, CARL9170_IDLE, CARL9170_STARTED);

        ieee80211_queue_delayed_work(ar->hw, &ar->stat_work,
                round_jiffies(msecs_to_jiffies(CARL9170_STAT_WORK)));

        ieee80211_wake_queues(ar->hw);
        err = 0;

out:
        mutex_unlock(&ar->mutex);
        return err;
}

static void carl9170_cancel_worker(struct ar9170 *ar)
{
        cancel_delayed_work_sync(&ar->stat_work);
        cancel_delayed_work_sync(&ar->tx_janitor);
#ifdef CONFIG_CARL9170_LEDS
        cancel_delayed_work_sync(&ar->led_work);
#endif /* CONFIG_CARL9170_LEDS */
        cancel_work_sync(&ar->ps_work);
        cancel_work_sync(&ar->ping_work);
        cancel_work_sync(&ar->ampdu_work);
}

static void carl9170_op_stop(struct ieee80211_hw *hw)
{
        struct ar9170 *ar = hw->priv;

        carl9170_set_state_when(ar, CARL9170_STARTED, CARL9170_IDLE);

        ieee80211_stop_queues(ar->hw);

        mutex_lock(&ar->mutex);
        if (IS_ACCEPTING_CMD(ar)) {
                RCU_INIT_POINTER(ar->beacon_iter, NULL);

                carl9170_led_set_state(ar, 0);

                /* stop DMA */
                carl9170_write_reg(ar, AR9170_MAC_REG_DMA_TRIGGER, 0);
                carl9170_usb_stop(ar);
        }

        carl9170_zap_queues(ar);
        mutex_unlock(&ar->mutex);

        carl9170_cancel_worker(ar);
}

static void carl9170_restart_work(struct work_struct *work)
{
        struct ar9170 *ar = container_of(work, struct ar9170,
                                         restart_work);
        int err = -EIO;

        ar->usedkeys = 0;
        ar->filter_state = 0;
        carl9170_cancel_worker(ar);

        mutex_lock(&ar->mutex);
        if (!ar->force_usb_reset) {
                err = carl9170_usb_restart(ar);
                if (net_ratelimit()) {
                        if (err)
                                dev_err(&ar->udev->dev, "Failed to restart device (%d).\n", err);
                        else
                                dev_info(&ar->udev->dev, "device restarted successfully.\n");
                }
        }
        carl9170_zap_queues(ar);
        mutex_unlock(&ar->mutex);

        if (!err && !ar->force_usb_reset) {
                ar->restart_counter++;
                atomic_set(&ar->pending_restarts, 0);

                ieee80211_restart_hw(ar->hw);
        } else {
                /*
                 * The reset was unsuccessful and the device seems to
                 * be dead. But there's still one option: a low-level
                 * usb subsystem reset...
                 */

                carl9170_usb_reset(ar);
        }
}

void carl9170_restart(struct ar9170 *ar, const enum carl9170_restart_reasons r)
{
        carl9170_set_state_when(ar, CARL9170_STARTED, CARL9170_IDLE);

        /*
         * Sometimes, an error can trigger several different reset events.
         * By ignoring these *surplus* reset events, the device won't be
         * killed again, right after it has recovered.
         */
        if (atomic_inc_return(&ar->pending_restarts) > 1) {
                dev_dbg(&ar->udev->dev, "ignoring restart (%d)\n", r);
                return;
        }

        ieee80211_stop_queues(ar->hw);

        dev_err(&ar->udev->dev, "restart device (%d)\n", r);

        if (!WARN_ON(r == CARL9170_RR_NO_REASON) ||
            !WARN_ON(r >= __CARL9170_RR_LAST))
                ar->last_reason = r;

        if (!ar->registered)
                return;

        if (!IS_ACCEPTING_CMD(ar) || ar->needs_full_reset)
                ar->force_usb_reset = true;

        ieee80211_queue_work(ar->hw, &ar->restart_work);

        /*
         * At this point, the device instance might have vanished/disabled.
         * So, don't put any code which access the ar9170 struct
         * without proper protection.
         */
}

static void carl9170_ping_work(struct work_struct *work)
{
        struct ar9170 *ar = container_of(work, struct ar9170, ping_work);
        int err;

        if (!IS_STARTED(ar))
                return;

        mutex_lock(&ar->mutex);
        err = carl9170_echo_test(ar, 0xdeadbeef);
        if (err)
                carl9170_restart(ar, CARL9170_RR_UNRESPONSIVE_DEVICE);
        mutex_unlock(&ar->mutex);
}

static int carl9170_init_interface(struct ar9170 *ar,
                                   struct ieee80211_vif *vif)
{
        struct ath_common *common = &ar->common;
        int err;

        if (!vif) {
                WARN_ON_ONCE(IS_STARTED(ar));
                return 0;
        }

        memcpy(common->macaddr, vif->addr, ETH_ALEN);

        /* We have to fall back to software crypto, whenever
         * the user choose to participates in an IBSS. HW
         * offload for IBSS RSN is not supported by this driver.
         *
         * NOTE: If the previous main interface has already
         * disabled hw crypto offload, we have to keep this
         * previous disable_offload setting as it was.
         * Altough ideally, we should notify mac80211 and tell
         * it to forget about any HW crypto offload for now.
         */
        ar->disable_offload |= ((vif->type != NL80211_IFTYPE_STATION) &&
            (vif->type != NL80211_IFTYPE_AP));

        /* The driver used to have P2P GO+CLIENT support,
         * but since this was dropped and we don't know if
         * there are any gremlins lurking in the shadows,
         * so best we keep HW offload disabled for P2P.
         */
        ar->disable_offload |= vif->p2p;

        ar->rx_software_decryption = ar->disable_offload;

        err = carl9170_set_operating_mode(ar);
        return err;
}

static int carl9170_op_add_interface(struct ieee80211_hw *hw,
                                     struct ieee80211_vif *vif)
{
        struct carl9170_vif_info *vif_priv = (void *) vif->drv_priv;
        struct ieee80211_vif *main_vif, *old_main = NULL;
        struct ar9170 *ar = hw->priv;
        int vif_id = -1, err = 0;

        mutex_lock(&ar->mutex);
        rcu_read_lock();
        if (vif_priv->active) {
                /*
                 * Skip the interface structure initialization,
                 * if the vif survived the _restart call.
                 */
                vif_id = vif_priv->id;
                vif_priv->enable_beacon = false;

                spin_lock_bh(&ar->beacon_lock);
                dev_kfree_skb_any(vif_priv->beacon);
                vif_priv->beacon = NULL;
                spin_unlock_bh(&ar->beacon_lock);

                goto init;
        }

        /* Because the AR9170 HW's MAC doesn't provide full support for
         * multiple, independent interfaces [of different operation modes].
         * We have to select ONE main interface [main mode of HW], but we
         * can have multiple slaves [AKA: entry in the ACK-table].
         *
         * The first (from HEAD/TOP) interface in the ar->vif_list is
         * always the main intf. All following intfs in this list
         * are considered to be slave intfs.
         */
        main_vif = carl9170_get_main_vif(ar);

        if (main_vif) {
                switch (main_vif->type) {
                case NL80211_IFTYPE_STATION:
                        if (vif->type == NL80211_IFTYPE_STATION)
                                break;

                        err = -EBUSY;
                        rcu_read_unlock();

                        goto unlock;

                case NL80211_IFTYPE_MESH_POINT:
                case NL80211_IFTYPE_AP:
                        if ((vif->type == NL80211_IFTYPE_STATION) ||
                            (vif->type == NL80211_IFTYPE_WDS) ||
                            (vif->type == NL80211_IFTYPE_AP) ||
                            (vif->type == NL80211_IFTYPE_MESH_POINT))
                                break;

                        err = -EBUSY;
                        rcu_read_unlock();
                        goto unlock;

                default:
                        rcu_read_unlock();
                        goto unlock;
                }
        }

        vif_id = bitmap_find_free_region(&ar->vif_bitmap, ar->fw.vif_num, 0);

        if (vif_id < 0) {
                rcu_read_unlock();

                err = -ENOSPC;
                goto unlock;
        }

        BUG_ON(ar->vif_priv[vif_id].id != vif_id);

        vif_priv->active = true;
        vif_priv->id = vif_id;
        vif_priv->enable_beacon = false;
        ar->vifs++;
        if (old_main) {
                /* We end up in here, if the main interface is being replaced.
                 * Put the new main interface at the HEAD of the list and the
                 * previous inteface will automatically become second in line.
                 */
                list_add_rcu(&vif_priv->list, &ar->vif_list);
        } else {
                /* Add new inteface. If the list is empty, it will become the
                 * main inteface, otherwise it will be slave.
                 */
                list_add_tail_rcu(&vif_priv->list, &ar->vif_list);
        }
        rcu_assign_pointer(ar->vif_priv[vif_id].vif, vif);

init:
        main_vif = carl9170_get_main_vif(ar);

        if (main_vif == vif) {
                rcu_assign_pointer(ar->beacon_iter, vif_priv);
                rcu_read_unlock();

                if (old_main) {
                        struct carl9170_vif_info *old_main_priv =
                                (void *) old_main->drv_priv;
                        /* downgrade old main intf to slave intf.
                         * NOTE: We are no longer under rcu_read_lock.
                         * But we are still holding ar->mutex, so the
                         * vif data [id, addr] is safe.
                         */
                        err = carl9170_mod_virtual_mac(ar, old_main_priv->id,
                                                       old_main->addr);
                        if (err)
                                goto unlock;
                }

                err = carl9170_init_interface(ar, vif);
                if (err)
                        goto unlock;
        } else {
                rcu_read_unlock();
                err = carl9170_mod_virtual_mac(ar, vif_id, vif->addr);

                if (err)
                        goto unlock;
        }

        if (ar->fw.tx_seq_table) {
                err = carl9170_write_reg(ar, ar->fw.tx_seq_table + vif_id * 4,
                                         0);
                if (err)
                        goto unlock;
        }

unlock:
        if (err && (vif_id >= 0)) {
                vif_priv->active = false;
                bitmap_release_region(&ar->vif_bitmap, vif_id, 0);
                ar->vifs--;
                RCU_INIT_POINTER(ar->vif_priv[vif_id].vif, NULL);
                list_del_rcu(&vif_priv->list);
                mutex_unlock(&ar->mutex);
                synchronize_rcu();
        } else {
                if (ar->vifs > 1)
                        ar->ps.off_override |= PS_OFF_VIF;

                mutex_unlock(&ar->mutex);
        }

        return err;
}

static void carl9170_op_remove_interface(struct ieee80211_hw *hw,
                                         struct ieee80211_vif *vif)
{
        struct carl9170_vif_info *vif_priv = (void *) vif->drv_priv;
        struct ieee80211_vif *main_vif;
        struct ar9170 *ar = hw->priv;
        unsigned int id;

        mutex_lock(&ar->mutex);

        if (WARN_ON_ONCE(!vif_priv->active))
                goto unlock;

        ar->vifs--;

        rcu_read_lock();
        main_vif = carl9170_get_main_vif(ar);

        id = vif_priv->id;

        vif_priv->active = false;
        WARN_ON(vif_priv->enable_beacon);
        vif_priv->enable_beacon = false;
        list_del_rcu(&vif_priv->list);
        RCU_INIT_POINTER(ar->vif_priv[id].vif, NULL);

        if (vif == main_vif) {
                rcu_read_unlock();

                if (ar->vifs) {
                        WARN_ON(carl9170_init_interface(ar,
                                        carl9170_get_main_vif(ar)));
                } else {
                        carl9170_set_operating_mode(ar);
                }
        } else {
                rcu_read_unlock();

                WARN_ON(carl9170_mod_virtual_mac(ar, id, NULL));
        }

        carl9170_update_beacon(ar, false);
        carl9170_flush_cab(ar, id);

        spin_lock_bh(&ar->beacon_lock);
        dev_kfree_skb_any(vif_priv->beacon);
        vif_priv->beacon = NULL;
        spin_unlock_bh(&ar->beacon_lock);

        bitmap_release_region(&ar->vif_bitmap, id, 0);

        carl9170_set_beacon_timers(ar);

        if (ar->vifs == 1)
                ar->ps.off_override &= ~PS_OFF_VIF;

unlock:
        mutex_unlock(&ar->mutex);

        synchronize_rcu();
}

void carl9170_ps_check(struct ar9170 *ar)
{
        ieee80211_queue_work(ar->hw, &ar->ps_work);
}

/* caller must hold ar->mutex */
static int carl9170_ps_update(struct ar9170 *ar)
{
        bool ps = false;
        int err = 0;

        if (!ar->ps.off_override)
                ps = (ar->hw->conf.flags & IEEE80211_CONF_PS);

        if (ps != ar->ps.state) {
                err = carl9170_powersave(ar, ps);
                if (err)
                        return err;

                if (ar->ps.state && !ps) {
                        ar->ps.sleep_ms = jiffies_to_msecs(jiffies -
                                ar->ps.last_action);
                }

                if (ps)
                        ar->ps.last_slept = jiffies;

                ar->ps.last_action = jiffies;
                ar->ps.state = ps;
        }

        return 0;
}

static void carl9170_ps_work(struct work_struct *work)
{
        struct ar9170 *ar = container_of(work, struct ar9170,
                                         ps_work);
        mutex_lock(&ar->mutex);
        if (IS_STARTED(ar))
                WARN_ON_ONCE(carl9170_ps_update(ar) != 0);
        mutex_unlock(&ar->mutex);
}

static int carl9170_update_survey(struct ar9170 *ar, bool flush, bool noise)
{
        int err;

        if (noise) {
                err = carl9170_get_noisefloor(ar);
                if (err)
                        return err;
        }

        if (ar->fw.hw_counters) {
                err = carl9170_collect_tally(ar);
                if (err)
                        return err;
        }

        if (flush)
                memset(&ar->tally, 0, sizeof(ar->tally));

        return 0;
}

static void carl9170_stat_work(struct work_struct *work)
{
        struct ar9170 *ar = container_of(work, struct ar9170, stat_work.work);
        int err;

        mutex_lock(&ar->mutex);
        err = carl9170_update_survey(ar, false, true);
        mutex_unlock(&ar->mutex);

        if (err)
                return;

        ieee80211_queue_delayed_work(ar->hw, &ar->stat_work,
                round_jiffies(msecs_to_jiffies(CARL9170_STAT_WORK)));
}

static int carl9170_op_config(struct ieee80211_hw *hw, u32 changed)
{
        struct ar9170 *ar = hw->priv;
        int err = 0;

        mutex_lock(&ar->mutex);
        if (changed & IEEE80211_CONF_CHANGE_LISTEN_INTERVAL) {
                /* TODO */
                err = 0;
        }

        if (changed & IEEE80211_CONF_CHANGE_PS) {
                err = carl9170_ps_update(ar);
                if (err)
                        goto out;
        }

        if (changed & IEEE80211_CONF_CHANGE_SMPS) {
                /* TODO */
                err = 0;
        }

        if (changed & IEEE80211_CONF_CHANGE_CHANNEL) {
                enum nl80211_channel_type channel_type =
                        cfg80211_get_chandef_type(&hw->conf.chandef);

                /* adjust slot time for 5 GHz */
                err = carl9170_set_slot_time(ar);
                if (err)
                        goto out;

                err = carl9170_update_survey(ar, true, false);
                if (err)
                        goto out;

                err = carl9170_set_channel(ar, hw->conf.chandef.chan,
                                           channel_type);
                if (err)
                        goto out;

                err = carl9170_update_survey(ar, false, true);
                if (err)
                        goto out;

                err = carl9170_set_dyn_sifs_ack(ar);
                if (err)
                        goto out;

                err = carl9170_set_rts_cts_rate(ar);
                if (err)
                        goto out;
        }

        if (changed & IEEE80211_CONF_CHANGE_POWER) {
                err = carl9170_set_mac_tpc(ar, ar->hw->conf.chandef.chan);
                if (err)
                        goto out;
        }

out:
        mutex_unlock(&ar->mutex);
        return err;
}

static u64 carl9170_op_prepare_multicast(struct ieee80211_hw *hw,
                                         struct netdev_hw_addr_list *mc_list)
{
        struct netdev_hw_addr *ha;
        u64 mchash;

        /* always get broadcast frames */
        mchash = 1ULL << (0xff >> 2);

        netdev_hw_addr_list_for_each(ha, mc_list)
                mchash |= 1ULL << (ha->addr[5] >> 2);

        return mchash;
}

static void carl9170_op_configure_filter(struct ieee80211_hw *hw,
                                         unsigned int changed_flags,
                                         unsigned int *new_flags,
                                         u64 multicast)
{
        struct ar9170 *ar = hw->priv;

        /* mask supported flags */
        *new_flags &= FIF_ALLMULTI | ar->rx_filter_caps;

        if (!IS_ACCEPTING_CMD(ar))
                return;

        mutex_lock(&ar->mutex);

        ar->filter_state = *new_flags;
        /*
         * We can support more by setting the sniffer bit and
         * then checking the error flags, later.
         */

        if (*new_flags & FIF_ALLMULTI)
                multicast = ~0ULL;

        if (multicast != ar->cur_mc_hash)
                WARN_ON(carl9170_update_multicast(ar, multicast));

        if (changed_flags & FIF_OTHER_BSS) {
                ar->sniffer_enabled = !!(*new_flags & FIF_OTHER_BSS);

                WARN_ON(carl9170_set_operating_mode(ar));
        }

        if (ar->fw.rx_filter && changed_flags & ar->rx_filter_caps) {
                u32 rx_filter = 0;

                if (!ar->fw.ba_filter)
                        rx_filter |= CARL9170_RX_FILTER_CTL_OTHER;

                if (!(*new_flags & (FIF_FCSFAIL | FIF_PLCPFAIL)))
                        rx_filter |= CARL9170_RX_FILTER_BAD;

                if (!(*new_flags & FIF_CONTROL))
                        rx_filter |= CARL9170_RX_FILTER_CTL_OTHER;

                if (!(*new_flags & FIF_PSPOLL))
                        rx_filter |= CARL9170_RX_FILTER_CTL_PSPOLL;

                if (!(*new_flags & FIF_OTHER_BSS)) {
                        rx_filter |= CARL9170_RX_FILTER_OTHER_RA;
                        rx_filter |= CARL9170_RX_FILTER_DECRY_FAIL;
                }

                WARN_ON(carl9170_rx_filter(ar, rx_filter));
        }

        mutex_unlock(&ar->mutex);
}


static void carl9170_op_bss_info_changed(struct ieee80211_hw *hw,
                                         struct ieee80211_vif *vif,
                                         struct ieee80211_bss_conf *bss_conf,
                                         u32 changed)
{
        struct ar9170 *ar = hw->priv;
        struct ath_common *common = &ar->common;
        int err = 0;
        struct carl9170_vif_info *vif_priv;
        struct ieee80211_vif *main_vif;

        mutex_lock(&ar->mutex);
        vif_priv = (void *) vif->drv_priv;
        main_vif = carl9170_get_main_vif(ar);
        if (WARN_ON(!main_vif))
                goto out;

        if (changed & BSS_CHANGED_BEACON_ENABLED) {
                struct carl9170_vif_info *iter;
                int i = 0;

                vif_priv->enable_beacon = bss_conf->enable_beacon;
                rcu_read_lock();
                list_for_each_entry_rcu(iter, &ar->vif_list, list) {
                        if (iter->active && iter->enable_beacon)
                                i++;

                }
                rcu_read_unlock();

                ar->beacon_enabled = i;
        }

        if (changed & BSS_CHANGED_BEACON) {
                err = carl9170_update_beacon(ar, false);
                if (err)
                        goto out;
        }

        if (changed & (BSS_CHANGED_BEACON_ENABLED | BSS_CHANGED_BEACON |
                       BSS_CHANGED_BEACON_INT)) {

                if (main_vif != vif) {
                        bss_conf->beacon_int = main_vif->bss_conf.beacon_int;
                        bss_conf->dtim_period = main_vif->bss_conf.dtim_period;
                }

                /*
                 * Therefore a hard limit for the broadcast traffic should
                 * prevent false alarms.
                 */
                if (vif->type != NL80211_IFTYPE_STATION &&
                    (bss_conf->beacon_int * bss_conf->dtim_period >=
                     (CARL9170_QUEUE_STUCK_TIMEOUT / 2))) {
                        err = -EINVAL;
                        goto out;
                }

                err = carl9170_set_beacon_timers(ar);
                if (err)
                        goto out;
        }

        if (changed & BSS_CHANGED_HT) {
                /* TODO */
                err = 0;
                if (err)
                        goto out;
        }

        if (main_vif != vif)
                goto out;

        /*
         * The following settings can only be changed by the
         * master interface.
         */

        if (changed & BSS_CHANGED_BSSID) {
                memcpy(common->curbssid, bss_conf->bssid, ETH_ALEN);
                err = carl9170_set_operating_mode(ar);
                if (err)
                        goto out;
        }

        if (changed & BSS_CHANGED_ASSOC) {
                ar->common.curaid = bss_conf->aid;
                err = carl9170_set_beacon_timers(ar);
                if (err)
                        goto out;
        }

        if (changed & BSS_CHANGED_ERP_SLOT) {
                err = carl9170_set_slot_time(ar);
                if (err)
                        goto out;
        }

        if (changed & BSS_CHANGED_BASIC_RATES) {
                err = carl9170_set_mac_rates(ar);
                if (err)
                        goto out;
        }

out:
        WARN_ON_ONCE(err && IS_STARTED(ar));
        mutex_unlock(&ar->mutex);
}

static u64 carl9170_op_get_tsf(struct ieee80211_hw *hw,
                               struct ieee80211_vif *vif)
{
        struct ar9170 *ar = hw->priv;
        struct carl9170_tsf_rsp tsf;
        int err;

        mutex_lock(&ar->mutex);
        err = carl9170_exec_cmd(ar, CARL9170_CMD_READ_TSF,
                                0, NULL, sizeof(tsf), &tsf);
        mutex_unlock(&ar->mutex);
        if (WARN_ON(err))
                return 0;

        return le64_to_cpu(tsf.tsf_64);
}

static int carl9170_op_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
                               struct ieee80211_vif *vif,
                               struct ieee80211_sta *sta,
                               struct ieee80211_key_conf *key)
{
        struct ar9170 *ar = hw->priv;
        int err = 0, i;
        u8 ktype;

        if (ar->disable_offload || !vif)
                return -EOPNOTSUPP;

        /* Fall back to software encryption whenever the driver is connected
         * to more than one network.
         *
         * This is very unfortunate, because some machines cannot handle
         * the high througput speed in 802.11n networks.
         */

        if (!is_main_vif(ar, vif)) {
                mutex_lock(&ar->mutex);
                goto err_softw;
        }

        /*
         * While the hardware supports *catch-all* key, for offloading
         * group-key en-/de-cryption. The way of how the hardware
         * decides which keyId maps to which key, remains a mystery...
         */
        if ((vif->type != NL80211_IFTYPE_STATION &&
             vif->type != NL80211_IFTYPE_ADHOC) &&
            !(key->flags & IEEE80211_KEY_FLAG_PAIRWISE))
                return -EOPNOTSUPP;

        switch (key->cipher) {
        case WLAN_CIPHER_SUITE_WEP40:
                ktype = AR9170_ENC_ALG_WEP64;
                break;
        case WLAN_CIPHER_SUITE_WEP104:
                ktype = AR9170_ENC_ALG_WEP128;
                break;
        case WLAN_CIPHER_SUITE_TKIP:
                ktype = AR9170_ENC_ALG_TKIP;
                break;
        case WLAN_CIPHER_SUITE_CCMP:
                ktype = AR9170_ENC_ALG_AESCCMP;
                key->flags |= IEEE80211_KEY_FLAG_SW_MGMT_TX;
                break;
        default:
                return -EOPNOTSUPP;
        }

        mutex_lock(&ar->mutex);
        if (cmd == SET_KEY) {
                if (!IS_STARTED(ar)) {
                        err = -EOPNOTSUPP;
                        goto out;
                }

                if (!(key->flags & IEEE80211_KEY_FLAG_PAIRWISE)) {
                        sta = NULL;

                        i = 64 + key->keyidx;
                } else {
                        for (i = 0; i < 64; i++)
                                if (!(ar->usedkeys & BIT(i)))
                                        break;
                        if (i == 64)
                                goto err_softw;
                }

                key->hw_key_idx = i;

                err = carl9170_upload_key(ar, i, sta ? sta->addr : NULL,
                                          ktype, 0, key->key,
                                          min_t(u8, 16, key->keylen));
                if (err)
                        goto out;

                if (key->cipher == WLAN_CIPHER_SUITE_TKIP) {
                        err = carl9170_upload_key(ar, i, sta ? sta->addr :
                                                  NULL, ktype, 1,
                                                  key->key + 16, 16);
                        if (err)
                                goto out;

                        /*
                         * hardware is not capable generating MMIC
                         * of fragmented frames!
                         */
                        key->flags |= IEEE80211_KEY_FLAG_GENERATE_MMIC;
                }

                if (i < 64)
                        ar->usedkeys |= BIT(i);

                key->flags |= IEEE80211_KEY_FLAG_GENERATE_IV;
        } else {
                if (!IS_STARTED(ar)) {
                        /* The device is gone... together with the key ;-) */
                        err = 0;
                        goto out;
                }

                if (key->hw_key_idx < 64) {
                        ar->usedkeys &= ~BIT(key->hw_key_idx);
                } else {
                        err = carl9170_upload_key(ar, key->hw_key_idx, NULL,
                                                  AR9170_ENC_ALG_NONE, 0,
                                                  NULL, 0);
                        if (err)
                                goto out;

                        if (key->cipher == WLAN_CIPHER_SUITE_TKIP) {
                                err = carl9170_upload_key(ar, key->hw_key_idx,
                                                          NULL,
                                                          AR9170_ENC_ALG_NONE,
                                                          1, NULL, 0);
                                if (err)
                                        goto out;
                        }

                }

                err = carl9170_disable_key(ar, key->hw_key_idx);
                if (err)
                        goto out;
        }

out:
        mutex_unlock(&ar->mutex);
        return err;

err_softw:
        if (!ar->rx_software_decryption) {
                ar->rx_software_decryption = true;
                carl9170_set_operating_mode(ar);
        }
        mutex_unlock(&ar->mutex);
        return -ENOSPC;
}

static int carl9170_op_sta_add(struct ieee80211_hw *hw,
                               struct ieee80211_vif *vif,
                               struct ieee80211_sta *sta)
{
        struct carl9170_sta_info *sta_info = (void *) sta->drv_priv;
        unsigned int i;

        atomic_set(&sta_info->pending_frames, 0);

        if (sta->ht_cap.ht_supported) {
                if (sta->ht_cap.ampdu_density > 6) {
                        /*
                         * HW does support 16us AMPDU density.
                         * No HT-Xmit for station.
                         */

                        return 0;
                }

                for (i = 0; i < ARRAY_SIZE(sta_info->agg); i++)
                        RCU_INIT_POINTER(sta_info->agg[i], NULL);

                sta_info->ampdu_max_len = 1 << (3 + sta->ht_cap.ampdu_factor);
                sta_info->ht_sta = true;
        }

        return 0;
}

static int carl9170_op_sta_remove(struct ieee80211_hw *hw,
                                struct ieee80211_vif *vif,
                                struct ieee80211_sta *sta)
{
        struct ar9170 *ar = hw->priv;
        struct carl9170_sta_info *sta_info = (void *) sta->drv_priv;
        unsigned int i;
        bool cleanup = false;

        if (sta->ht_cap.ht_supported) {

                sta_info->ht_sta = false;

                rcu_read_lock();
                for (i = 0; i < ARRAY_SIZE(sta_info->agg); i++) {
                        struct carl9170_sta_tid *tid_info;

                        tid_info = rcu_dereference(sta_info->agg[i]);
                        RCU_INIT_POINTER(sta_info->agg[i], NULL);

                        if (!tid_info)
                                continue;

                        spin_lock_bh(&ar->tx_ampdu_list_lock);
                        if (tid_info->state > CARL9170_TID_STATE_SHUTDOWN)
                                tid_info->state = CARL9170_TID_STATE_SHUTDOWN;
                        spin_unlock_bh(&ar->tx_ampdu_list_lock);
                        cleanup = true;
                }
                rcu_read_unlock();

                if (cleanup)
                        carl9170_ampdu_gc(ar);
        }

        return 0;
}

static int carl9170_op_conf_tx(struct ieee80211_hw *hw,
                               struct ieee80211_vif *vif, u16 queue,
                               const struct ieee80211_tx_queue_params *param)
{
        struct ar9170 *ar = hw->priv;
        int ret;

        mutex_lock(&ar->mutex);
        memcpy(&ar->edcf[ar9170_qmap[queue]], param, sizeof(*param));
        ret = carl9170_set_qos(ar);
        mutex_unlock(&ar->mutex);
        return ret;
}

static void carl9170_ampdu_work(struct work_struct *work)
{
        struct ar9170 *ar = container_of(work, struct ar9170,
                                         ampdu_work);

        if (!IS_STARTED(ar))
                return;

        mutex_lock(&ar->mutex);
        carl9170_ampdu_gc(ar);
        mutex_unlock(&ar->mutex);
}

static int carl9170_op_ampdu_action(struct ieee80211_hw *hw,
                                    struct ieee80211_vif *vif,
                                    struct ieee80211_ampdu_params *params)
{
        struct ieee80211_sta *sta = params->sta;
        enum ieee80211_ampdu_mlme_action action = params->action;
        u16 tid = params->tid;
        u16 *ssn = &params->ssn;
        struct ar9170 *ar = hw->priv;
        struct carl9170_sta_info *sta_info = (void *) sta->drv_priv;
        struct carl9170_sta_tid *tid_info;

        if (modparam_noht)
                return -EOPNOTSUPP;

        switch (action) {
        case IEEE80211_AMPDU_TX_START:
                if (!sta_info->ht_sta)
                        return -EOPNOTSUPP;

                tid_info = kzalloc(sizeof(struct carl9170_sta_tid),
                                   GFP_ATOMIC);
                if (!tid_info)
                        return -ENOMEM;

                tid_info->hsn = tid_info->bsn = tid_info->snx = (*ssn);
                tid_info->state = CARL9170_TID_STATE_PROGRESS;
                tid_info->tid = tid;
                tid_info->max = sta_info->ampdu_max_len;
                tid_info->sta = sta;
                tid_info->vif = vif;

                INIT_LIST_HEAD(&tid_info->list);
                INIT_LIST_HEAD(&tid_info->tmp_list);
                skb_queue_head_init(&tid_info->queue);
                spin_lock_init(&tid_info->lock);

                spin_lock_bh(&ar->tx_ampdu_list_lock);
                ar->tx_ampdu_list_len++;
                list_add_tail_rcu(&tid_info->list, &ar->tx_ampdu_list);
                rcu_assign_pointer(sta_info->agg[tid], tid_info);
                spin_unlock_bh(&ar->tx_ampdu_list_lock);

                return IEEE80211_AMPDU_TX_START_IMMEDIATE;

        case IEEE80211_AMPDU_TX_STOP_CONT:
        case IEEE80211_AMPDU_TX_STOP_FLUSH:
        case IEEE80211_AMPDU_TX_STOP_FLUSH_CONT:
                rcu_read_lock();
                tid_info = rcu_dereference(sta_info->agg[tid]);
                if (tid_info) {
                        spin_lock_bh(&ar->tx_ampdu_list_lock);
                        if (tid_info->state > CARL9170_TID_STATE_SHUTDOWN)
                                tid_info->state = CARL9170_TID_STATE_SHUTDOWN;
                        spin_unlock_bh(&ar->tx_ampdu_list_lock);
                }

                RCU_INIT_POINTER(sta_info->agg[tid], NULL);
                rcu_read_unlock();

                ieee80211_stop_tx_ba_cb_irqsafe(vif, sta->addr, tid);
                ieee80211_queue_work(ar->hw, &ar->ampdu_work);
                break;

        case IEEE80211_AMPDU_TX_OPERATIONAL:
                rcu_read_lock();
                tid_info = rcu_dereference(sta_info->agg[tid]);

                sta_info->stats[tid].clear = true;
                sta_info->stats[tid].req = false;

                if (tid_info) {
                        bitmap_zero(tid_info->bitmap, CARL9170_BAW_SIZE);
                        tid_info->state = CARL9170_TID_STATE_IDLE;
                }
                rcu_read_unlock();

                if (WARN_ON_ONCE(!tid_info))
                        return -EFAULT;

                break;

        case IEEE80211_AMPDU_RX_START:
        case IEEE80211_AMPDU_RX_STOP:
                /* Handled by hardware */
                break;

        default:
                return -EOPNOTSUPP;
        }

        return 0;
}

#ifdef CONFIG_CARL9170_WPC
static int carl9170_register_wps_button(struct ar9170 *ar)
{
        struct input_dev *input;
        int err;

        if (!(ar->features & CARL9170_WPS_BUTTON))
                return 0;

        input = input_allocate_device();
        if (!input)
                return -ENOMEM;

        snprintf(ar->wps.name, sizeof(ar->wps.name), "%s WPS Button",
                 wiphy_name(ar->hw->wiphy));

        snprintf(ar->wps.phys, sizeof(ar->wps.phys),
                 "ieee80211/%s/input0", wiphy_name(ar->hw->wiphy));

        input->name = ar->wps.name;
        input->phys = ar->wps.phys;
        input->id.bustype = BUS_USB;
        input->dev.parent = &ar->hw->wiphy->dev;

        input_set_capability(input, EV_KEY, KEY_WPS_BUTTON);

        err = input_register_device(input);
        if (err) {
                input_free_device(input);
                return err;
        }

        ar->wps.pbc = input;
        return 0;
}
#endif /* CONFIG_CARL9170_WPC */

#ifdef CONFIG_CARL9170_HWRNG
static int carl9170_rng_get(struct ar9170 *ar)
{

#define RW      (CARL9170_MAX_CMD_PAYLOAD_LEN / sizeof(u32))
#define RB      (CARL9170_MAX_CMD_PAYLOAD_LEN)

        static const __le32 rng_load[RW] = {
                [0 ... (RW - 1)] = cpu_to_le32(AR9170_RAND_REG_NUM)};

        u32 buf[RW];

        unsigned int i, off = 0, transfer, count;
        int err;

        BUILD_BUG_ON(RB > CARL9170_MAX_CMD_PAYLOAD_LEN);

        if (!IS_ACCEPTING_CMD(ar) || !ar->rng.initialized)
                return -EAGAIN;

        count = ARRAY_SIZE(ar->rng.cache);
        while (count) {
                err = carl9170_exec_cmd(ar, CARL9170_CMD_RREG,
                                        RB, (u8 *) rng_load,
                                        RB, (u8 *) buf);
                if (err)
                        return err;

                transfer = min_t(unsigned int, count, RW);
                for (i = 0; i < transfer; i++)
                        ar->rng.cache[off + i] = buf[i];

                off += transfer;
                count -= transfer;
        }

        ar->rng.cache_idx = 0;

#undef RW
#undef RB
        return 0;
}

static int carl9170_rng_read(struct hwrng *rng, u32 *data)
{
        struct ar9170 *ar = (struct ar9170 *)rng->priv;
        int ret = -EIO;

        mutex_lock(&ar->mutex);
        if (ar->rng.cache_idx >= ARRAY_SIZE(ar->rng.cache)) {
                ret = carl9170_rng_get(ar);
                if (ret) {
                        mutex_unlock(&ar->mutex);
                        return ret;
                }
        }

        *data = ar->rng.cache[ar->rng.cache_idx++];
        mutex_unlock(&ar->mutex);

        return sizeof(u16);
}

static void carl9170_unregister_hwrng(struct ar9170 *ar)
{
        if (ar->rng.initialized) {
                hwrng_unregister(&ar->rng.rng);
                ar->rng.initialized = false;
        }
}

static int carl9170_register_hwrng(struct ar9170 *ar)
{
        int err;

        snprintf(ar->rng.name, ARRAY_SIZE(ar->rng.name),
                 "%s_%s", KBUILD_MODNAME, wiphy_name(ar->hw->wiphy));
        ar->rng.rng.name = ar->rng.name;
        ar->rng.rng.data_read = carl9170_rng_read;
        ar->rng.rng.priv = (unsigned long)ar;

        if (WARN_ON(ar->rng.initialized))
                return -EALREADY;

        err = hwrng_register(&ar->rng.rng);
        if (err) {
                dev_err(&ar->udev->dev, "Failed to register the random "
                        "number generator (%d)\n", err);
                return err;
        }

        ar->rng.initialized = true;

        err = carl9170_rng_get(ar);
        if (err) {
                carl9170_unregister_hwrng(ar);
                return err;
        }

        return 0;
}
#endif /* CONFIG_CARL9170_HWRNG */

static int carl9170_op_get_survey(struct ieee80211_hw *hw, int idx,
                                struct survey_info *survey)
{
        struct ar9170 *ar = hw->priv;
        struct ieee80211_channel *chan;
        struct ieee80211_supported_band *band;
        int err, b, i;

        chan = ar->channel;
        if (!chan)
                return -ENODEV;

        if (idx == chan->hw_value) {
                mutex_lock(&ar->mutex);
                err = carl9170_update_survey(ar, false, true);
                mutex_unlock(&ar->mutex);
                if (err)
                        return err;
        }

        for (b = 0; b < NUM_NL80211_BANDS; b++) {
                band = ar->hw->wiphy->bands[b];

                if (!band)
                        continue;

                for (i = 0; i < band->n_channels; i++) {
                        if (band->channels[i].hw_value == idx) {
                                chan = &band->channels[i];
                                goto found;
                        }
                }
        }
        return -ENOENT;

found:
        memcpy(survey, &ar->survey[idx], sizeof(*survey));

        survey->channel = chan;
        survey->filled = SURVEY_INFO_NOISE_DBM;

        if (ar->channel == chan)
                survey->filled |= SURVEY_INFO_IN_USE;

        if (ar->fw.hw_counters) {
                survey->filled |= SURVEY_INFO_TIME |
                                  SURVEY_INFO_TIME_BUSY |
                                  SURVEY_INFO_TIME_TX;
        }

        return 0;
}

static void carl9170_op_flush(struct ieee80211_hw *hw,
                              struct ieee80211_vif *vif,
                              u32 queues, bool drop)
{
        struct ar9170 *ar = hw->priv;
        unsigned int vid;

        mutex_lock(&ar->mutex);
        for_each_set_bit(vid, &ar->vif_bitmap, ar->fw.vif_num)
                carl9170_flush_cab(ar, vid);

        carl9170_flush(ar, drop);
        mutex_unlock(&ar->mutex);
}

static int carl9170_op_get_stats(struct ieee80211_hw *hw,
                                 struct ieee80211_low_level_stats *stats)
{
        struct ar9170 *ar = hw->priv;

        memset(stats, 0, sizeof(*stats));
        stats->dot11ACKFailureCount = ar->tx_ack_failures;
        stats->dot11FCSErrorCount = ar->tx_fcs_errors;
        return 0;
}

static void carl9170_op_sta_notify(struct ieee80211_hw *hw,
                                   struct ieee80211_vif *vif,
                                   enum sta_notify_cmd cmd,
                                   struct ieee80211_sta *sta)
{
        struct carl9170_sta_info *sta_info = (void *) sta->drv_priv;

        switch (cmd) {
        case STA_NOTIFY_SLEEP:
                sta_info->sleeping = true;
                if (atomic_read(&sta_info->pending_frames))
                        ieee80211_sta_block_awake(hw, sta, true);
                break;

        case STA_NOTIFY_AWAKE:
                sta_info->sleeping = false;
                break;
        }
}

static bool carl9170_tx_frames_pending(struct ieee80211_hw *hw)
{
        struct ar9170 *ar = hw->priv;

        return !!atomic_read(&ar->tx_total_queued);
}

static const struct ieee80211_ops carl9170_ops = {
        .start                  = carl9170_op_start,
        .stop                   = carl9170_op_stop,
        .tx                     = carl9170_op_tx,
        .flush                  = carl9170_op_flush,
        .add_interface          = carl9170_op_add_interface,
        .remove_interface       = carl9170_op_remove_interface,
        .config                 = carl9170_op_config,
        .prepare_multicast      = carl9170_op_prepare_multicast,
        .configure_filter       = carl9170_op_configure_filter,
        .conf_tx                = carl9170_op_conf_tx,
        .bss_info_changed       = carl9170_op_bss_info_changed,
        .get_tsf                = carl9170_op_get_tsf,
        .set_key                = carl9170_op_set_key,
        .sta_add                = carl9170_op_sta_add,
        .sta_remove             = carl9170_op_sta_remove,
        .sta_notify             = carl9170_op_sta_notify,
        .get_survey             = carl9170_op_get_survey,
        .get_stats              = carl9170_op_get_stats,
        .ampdu_action           = carl9170_op_ampdu_action,
        .tx_frames_pending      = carl9170_tx_frames_pending,
};

void *carl9170_alloc(size_t priv_size)
{
        struct ieee80211_hw *hw;
        struct ar9170 *ar;
        struct sk_buff *skb;
        int i;

        /*
         * this buffer is used for rx stream reconstruction.
         * Under heavy load this device (or the transport layer?)
         * tends to split the streams into separate rx descriptors.
         */

        skb = __dev_alloc_skb(AR9170_RX_STREAM_MAX_SIZE, GFP_KERNEL);
        if (!skb)
                goto err_nomem;

        hw = ieee80211_alloc_hw(priv_size, &carl9170_ops);
        if (!hw)
                goto err_nomem;

        ar = hw->priv;
        ar->hw = hw;
        ar->rx_failover = skb;

        memset(&ar->rx_plcp, 0, sizeof(struct ar9170_rx_head));
        ar->rx_has_plcp = false;

        /*
         * Here's a hidden pitfall!
         *
         * All 4 AC queues work perfectly well under _legacy_ operation.
         * However as soon as aggregation is enabled, the traffic flow
         * gets very bumpy. Therefore we have to _switch_ to a
         * software AC with a single HW queue.
         */
        hw->queues = __AR9170_NUM_TXQ;

        mutex_init(&ar->mutex);
        spin_lock_init(&ar->beacon_lock);
        spin_lock_init(&ar->cmd_lock);
        spin_lock_init(&ar->tx_stats_lock);
        spin_lock_init(&ar->tx_ampdu_list_lock);
        spin_lock_init(&ar->mem_lock);
        spin_lock_init(&ar->state_lock);
        atomic_set(&ar->pending_restarts, 0);
        ar->vifs = 0;
        for (i = 0; i < ar->hw->queues; i++) {
                skb_queue_head_init(&ar->tx_status[i]);
                skb_queue_head_init(&ar->tx_pending[i]);

                INIT_LIST_HEAD(&ar->bar_list[i]);
                spin_lock_init(&ar->bar_list_lock[i]);
        }
        INIT_WORK(&ar->ps_work, carl9170_ps_work);
        INIT_WORK(&ar->ping_work, carl9170_ping_work);
        INIT_WORK(&ar->restart_work, carl9170_restart_work);
        INIT_WORK(&ar->ampdu_work, carl9170_ampdu_work);
        INIT_DELAYED_WORK(&ar->stat_work, carl9170_stat_work);
        INIT_DELAYED_WORK(&ar->tx_janitor, carl9170_tx_janitor);
        INIT_LIST_HEAD(&ar->tx_ampdu_list);
        rcu_assign_pointer(ar->tx_ampdu_iter,
                           (struct carl9170_sta_tid *) &ar->tx_ampdu_list);

        bitmap_zero(&ar->vif_bitmap, ar->fw.vif_num);
        INIT_LIST_HEAD(&ar->vif_list);
        init_completion(&ar->tx_flush);

        /* firmware decides which modes we support */
        hw->wiphy->interface_modes = 0;

        ieee80211_hw_set(hw, RX_INCLUDES_FCS);
        ieee80211_hw_set(hw, MFP_CAPABLE);
        ieee80211_hw_set(hw, REPORTS_TX_ACK_STATUS);
        ieee80211_hw_set(hw, SUPPORTS_PS);
        ieee80211_hw_set(hw, PS_NULLFUNC_STACK);
        ieee80211_hw_set(hw, NEED_DTIM_BEFORE_ASSOC);
        ieee80211_hw_set(hw, SUPPORTS_RC_TABLE);
        ieee80211_hw_set(hw, SIGNAL_DBM);
        ieee80211_hw_set(hw, SUPPORTS_HT_CCK_RATES);

        if (!modparam_noht) {
                /*
                 * see the comment above, why we allow the user
                 * to disable HT by a module parameter.
                 */
                ieee80211_hw_set(hw, AMPDU_AGGREGATION);
        }

        hw->extra_tx_headroom = sizeof(struct _carl9170_tx_superframe);
        hw->sta_data_size = sizeof(struct carl9170_sta_info);
        hw->vif_data_size = sizeof(struct carl9170_vif_info);

        hw->max_rates = CARL9170_TX_MAX_RATES;
        hw->max_rate_tries = CARL9170_TX_USER_RATE_TRIES;

        for (i = 0; i < ARRAY_SIZE(ar->noise); i++)
                ar->noise[i] = -95; /* ATH_DEFAULT_NOISE_FLOOR */

        wiphy_ext_feature_set(hw->wiphy, NL80211_EXT_FEATURE_CQM_RSSI_LIST);

        return ar;

err_nomem:
        kfree_skb(skb);
        return ERR_PTR(-ENOMEM);
}

static int carl9170_read_eeprom(struct ar9170 *ar)
{
#define RW      8       /* number of words to read at once */
#define RB      (sizeof(u32) * RW)
        u8 *eeprom = (void *)&ar->eeprom;
        __le32 offsets[RW];
        int i, j, err;

        BUILD_BUG_ON(sizeof(ar->eeprom) & 3);

        BUILD_BUG_ON(RB > CARL9170_MAX_CMD_LEN - 4);
#ifndef __CHECKER__
        /* don't want to handle trailing remains */
        BUILD_BUG_ON(sizeof(ar->eeprom) % RB);
#endif

        for (i = 0; i < sizeof(ar->eeprom) / RB; i++) {
                for (j = 0; j < RW; j++)
                        offsets[j] = cpu_to_le32(AR9170_EEPROM_START +
                                                 RB * i + 4 * j);

                err = carl9170_exec_cmd(ar, CARL9170_CMD_RREG,
                                        RB, (u8 *) &offsets,
                                        RB, eeprom + RB * i);
                if (err)
                        return err;
        }

#undef RW
#undef RB
        return 0;
}

static int carl9170_parse_eeprom(struct ar9170 *ar)
{
        struct ath_regulatory *regulatory = &ar->common.regulatory;
        unsigned int rx_streams, tx_streams, tx_params = 0;
        int bands = 0;
        int chans = 0;

        if (ar->eeprom.length == cpu_to_le16(0xffff))
                return -ENODATA;

        rx_streams = hweight8(ar->eeprom.rx_mask);
        tx_streams = hweight8(ar->eeprom.tx_mask);

        if (rx_streams != tx_streams) {
                tx_params = IEEE80211_HT_MCS_TX_RX_DIFF;

                WARN_ON(!(tx_streams >= 1 && tx_streams <=
                        IEEE80211_HT_MCS_TX_MAX_STREAMS));

                tx_params = (tx_streams - 1) <<
                            IEEE80211_HT_MCS_TX_MAX_STREAMS_SHIFT;

                carl9170_band_2GHz.ht_cap.mcs.tx_params |= tx_params;
                carl9170_band_5GHz.ht_cap.mcs.tx_params |= tx_params;
        }

        if (ar->eeprom.operating_flags & AR9170_OPFLAG_2GHZ) {
                ar->hw->wiphy->bands[NL80211_BAND_2GHZ] =
                        &carl9170_band_2GHz;
                chans += carl9170_band_2GHz.n_channels;
                bands++;
        }
        if (ar->eeprom.operating_flags & AR9170_OPFLAG_5GHZ) {
                ar->hw->wiphy->bands[NL80211_BAND_5GHZ] =
                        &carl9170_band_5GHz;
                chans += carl9170_band_5GHz.n_channels;
                bands++;
        }

        if (!bands)
                return -EINVAL;

        ar->survey = kcalloc(chans, sizeof(struct survey_info), GFP_KERNEL);
        if (!ar->survey)
                return -ENOMEM;
        ar->num_channels = chans;

        regulatory->current_rd = le16_to_cpu(ar->eeprom.reg_domain[0]);

        /* second part of wiphy init */
        SET_IEEE80211_PERM_ADDR(ar->hw, ar->eeprom.mac_address);

        return 0;
}

static void carl9170_reg_notifier(struct wiphy *wiphy,
                                  struct regulatory_request *request)
{
        struct ieee80211_hw *hw = wiphy_to_ieee80211_hw(wiphy);
        struct ar9170 *ar = hw->priv;

        ath_reg_notifier_apply(wiphy, request, &ar->common.regulatory);
}

int carl9170_register(struct ar9170 *ar)
{
        struct ath_regulatory *regulatory = &ar->common.regulatory;
        int err = 0, i;

        if (WARN_ON(ar->mem_bitmap))
                return -EINVAL;

        ar->mem_bitmap = kcalloc(roundup(ar->fw.mem_blocks, BITS_PER_LONG),
                                 sizeof(unsigned long),
                                 GFP_KERNEL);

        if (!ar->mem_bitmap)
                return -ENOMEM;

        /* try to read EEPROM, init MAC addr */
        err = carl9170_read_eeprom(ar);
        if (err)
                return err;

        err = carl9170_parse_eeprom(ar);
        if (err)
                return err;

        err = ath_regd_init(regulatory, ar->hw->wiphy,
                            carl9170_reg_notifier);
        if (err)
                return err;

        if (modparam_noht) {
                carl9170_band_2GHz.ht_cap.ht_supported = false;
                carl9170_band_5GHz.ht_cap.ht_supported = false;
        }

        for (i = 0; i < ar->fw.vif_num; i++) {
                ar->vif_priv[i].id = i;
                ar->vif_priv[i].vif = NULL;

        }

        err = ieee80211_register_hw(ar->hw);
        if (err)
                return err;

        /* mac80211 interface is now registered */
        ar->registered = true;

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

#ifdef CONFIG_CARL9170_DEBUGFS
        carl9170_debugfs_register(ar);
#endif /* CONFIG_CARL9170_DEBUGFS */

        err = carl9170_led_init(ar);
        if (err)
                goto err_unreg;

#ifdef CONFIG_CARL9170_LEDS
        err = carl9170_led_register(ar);
        if (err)
                goto err_unreg;
#endif /* CONFIG_CARL9170_LEDS */

#ifdef CONFIG_CARL9170_WPC
        err = carl9170_register_wps_button(ar);
        if (err)
                goto err_unreg;
#endif /* CONFIG_CARL9170_WPC */

#ifdef CONFIG_CARL9170_HWRNG
        err = carl9170_register_hwrng(ar);
        if (err)
                goto err_unreg;
#endif /* CONFIG_CARL9170_HWRNG */

        dev_info(&ar->udev->dev, "Atheros AR9170 is registered as '%s'\n",
                 wiphy_name(ar->hw->wiphy));

        return 0;

err_unreg:
        carl9170_unregister(ar);
        return err;
}

void carl9170_unregister(struct ar9170 *ar)
{
        if (!ar->registered)
                return;

        ar->registered = false;

#ifdef CONFIG_CARL9170_LEDS
        carl9170_led_unregister(ar);
#endif /* CONFIG_CARL9170_LEDS */

#ifdef CONFIG_CARL9170_DEBUGFS
        carl9170_debugfs_unregister(ar);
#endif /* CONFIG_CARL9170_DEBUGFS */

#ifdef CONFIG_CARL9170_WPC
        if (ar->wps.pbc) {
                input_unregister_device(ar->wps.pbc);
                ar->wps.pbc = NULL;
        }
#endif /* CONFIG_CARL9170_WPC */

#ifdef CONFIG_CARL9170_HWRNG
        carl9170_unregister_hwrng(ar);
#endif /* CONFIG_CARL9170_HWRNG */

        carl9170_cancel_worker(ar);
        cancel_work_sync(&ar->restart_work);

        ieee80211_unregister_hw(ar->hw);
}

void carl9170_free(struct ar9170 *ar)
{
        WARN_ON(ar->registered);
        WARN_ON(IS_INITIALIZED(ar));

        kfree_skb(ar->rx_failover);
        ar->rx_failover = NULL;

        kfree(ar->mem_bitmap);
        ar->mem_bitmap = NULL;

        kfree(ar->survey);
        ar->survey = NULL;

        mutex_destroy(&ar->mutex);

        ieee80211_free_hw(ar->hw);
}