txrx.c

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/*
 * Copyright (c) 2004-2011 Atheros Communications Inc.
 * Copyright (c) 2011-2012 Qualcomm Atheros, 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include "core.h"
#include "debug.h"
#include "htc-ops.h"

/*
 * tid - tid_mux0..tid_mux3
 * aid - tid_mux4..tid_mux7
 */
#define ATH6KL_TID_MASK 0xf
#define ATH6KL_AID_SHIFT 4

static inline u8 ath6kl_get_tid(u8 tid_mux)
{
    return tid_mux & ATH6KL_TID_MASK;
}

static inline u8 ath6kl_get_aid(u8 tid_mux)
{
    return tid_mux >> ATH6KL_AID_SHIFT;
}

static u8 ath6kl_ibss_map_epid(struct sk_buff *skb, struct net_device *dev,
                   u32 *map_no)
{
    struct ath6kl *ar = ath6kl_priv(dev);
    struct ethhdr *eth_hdr;
    u32 i, ep_map = -1;
    u8 *datap;

    *map_no = 0;
    datap = skb->data;
    eth_hdr = (struct ethhdr *) (datap + sizeof(struct wmi_data_hdr));

    if (is_multicast_ether_addr(eth_hdr->h_dest))
        return ENDPOINT_2;

    for (i = 0; i < ar->node_num; i++) {
        if (memcmp(eth_hdr->h_dest, ar->node_map[i].mac_addr,
               ETH_ALEN) == 0) {
            *map_no = i + 1;
            ar->node_map[i].tx_pend++;
            return ar->node_map[i].ep_id;
        }

        if ((ep_map == -1) && !ar->node_map[i].tx_pend)
            ep_map = i;
    }

    if (ep_map == -1) {
        ep_map = ar->node_num;
        ar->node_num++;
        if (ar->node_num > MAX_NODE_NUM)
            return ENDPOINT_UNUSED;
    }

    memcpy(ar->node_map[ep_map].mac_addr, eth_hdr->h_dest, ETH_ALEN);

    for (i = ENDPOINT_2; i <= ENDPOINT_5; i++) {
        if (!ar->tx_pending[i]) {
            ar->node_map[ep_map].ep_id = i;
            break;
        }

        /*
         * No free endpoint is available, start redistribution on
         * the inuse endpoints.
         */
        if (i == ENDPOINT_5) {
            ar->node_map[ep_map].ep_id = ar->next_ep_id;
            ar->next_ep_id++;
            if (ar->next_ep_id > ENDPOINT_5)
                ar->next_ep_id = ENDPOINT_2;
        }
    }

    *map_no = ep_map + 1;
    ar->node_map[ep_map].tx_pend++;

    return ar->node_map[ep_map].ep_id;
}

static bool ath6kl_process_uapsdq(struct ath6kl_sta *conn,
                struct ath6kl_vif *vif,
                struct sk_buff *skb,
                u32 *flags)
{
    struct ath6kl *ar = vif->ar;
    bool is_apsdq_empty = false;
    struct ethhdr *datap = (struct ethhdr *) skb->data;
    u8 up = 0, traffic_class, *ip_hdr;
    u16 ether_type;
    struct ath6kl_llc_snap_hdr *llc_hdr;

    if (conn->sta_flags & STA_PS_APSD_TRIGGER) {
        /*
         * This tx is because of a uAPSD trigger, determine
         * more and EOSP bit. Set EOSP if queue is empty
         * or sufficient frames are delivered for this trigger.
         */
        spin_lock_bh(&conn->psq_lock);
        if (!skb_queue_empty(&conn->apsdq))
            *flags |= WMI_DATA_HDR_FLAGS_MORE;
        else if (conn->sta_flags & STA_PS_APSD_EOSP)
            *flags |= WMI_DATA_HDR_FLAGS_EOSP;
        *flags |= WMI_DATA_HDR_FLAGS_UAPSD;
        spin_unlock_bh(&conn->psq_lock);
        return false;
    } else if (!conn->apsd_info)
        return false;

    if (test_bit(WMM_ENABLED, &vif->flags)) {
        ether_type = be16_to_cpu(datap->h_proto);
        if (is_ethertype(ether_type)) {
            /* packet is in DIX format  */
            ip_hdr = (u8 *)(datap + 1);
        } else {
            /* packet is in 802.3 format */
            llc_hdr = (struct ath6kl_llc_snap_hdr *)
                            (datap + 1);
            ether_type = be16_to_cpu(llc_hdr->eth_type);
            ip_hdr = (u8 *)(llc_hdr + 1);
        }

        if (ether_type == IP_ETHERTYPE)
            up = ath6kl_wmi_determine_user_priority(
                            ip_hdr, 0);
    }

    traffic_class = ath6kl_wmi_get_traffic_class(up);

    if ((conn->apsd_info & (1 << traffic_class)) == 0)
        return false;

    /* Queue the frames if the STA is sleeping */
    spin_lock_bh(&conn->psq_lock);
    is_apsdq_empty = skb_queue_empty(&conn->apsdq);
    skb_queue_tail(&conn->apsdq, skb);
    spin_unlock_bh(&conn->psq_lock);

    /*
     * If this is the first pkt getting queued
     * for this STA, update the PVB for this STA
     */
    if (is_apsdq_empty) {
        ath6kl_wmi_set_apsd_bfrd_traf(ar->wmi,
                          vif->fw_vif_idx,
                          conn->aid, 1, 0);
    }
    *flags |= WMI_DATA_HDR_FLAGS_UAPSD;

    return true;
}

static bool ath6kl_process_psq(struct ath6kl_sta *conn,
                struct ath6kl_vif *vif,
                struct sk_buff *skb,
                u32 *flags)
{
    bool is_psq_empty = false;
    struct ath6kl *ar = vif->ar;

    if (conn->sta_flags & STA_PS_POLLED) {
        spin_lock_bh(&conn->psq_lock);
        if (!skb_queue_empty(&conn->psq))
            *flags |= WMI_DATA_HDR_FLAGS_MORE;
        spin_unlock_bh(&conn->psq_lock);
        return false;
    }

    /* Queue the frames if the STA is sleeping */
    spin_lock_bh(&conn->psq_lock);
    is_psq_empty = skb_queue_empty(&conn->psq);
    skb_queue_tail(&conn->psq, skb);
    spin_unlock_bh(&conn->psq_lock);

    /*
     * If this is the first pkt getting queued
     * for this STA, update the PVB for this
     * STA.
     */
    if (is_psq_empty)
        ath6kl_wmi_set_pvb_cmd(ar->wmi,
                       vif->fw_vif_idx,
                       conn->aid, 1);
    return true;
}

static bool ath6kl_powersave_ap(struct ath6kl_vif *vif, struct sk_buff *skb,
                u32 *flags)
{
    struct ethhdr *datap = (struct ethhdr *) skb->data;
    struct ath6kl_sta *conn = NULL;
    bool ps_queued = false;
    struct ath6kl *ar = vif->ar;

    if (is_multicast_ether_addr(datap->h_dest)) {
        u8 ctr = 0;
        bool q_mcast = false;

        for (ctr = 0; ctr < AP_MAX_NUM_STA; ctr++) {
            if (ar->sta_list[ctr].sta_flags & STA_PS_SLEEP) {
                q_mcast = true;
                break;
            }
        }

        if (q_mcast) {
            /*
             * If this transmit is not because of a Dtim Expiry
             * q it.
             */
            if (!test_bit(DTIM_EXPIRED, &vif->flags)) {
                bool is_mcastq_empty = false;

                spin_lock_bh(&ar->mcastpsq_lock);
                is_mcastq_empty =
                    skb_queue_empty(&ar->mcastpsq);
                skb_queue_tail(&ar->mcastpsq, skb);
                spin_unlock_bh(&ar->mcastpsq_lock);

                /*
                 * If this is the first Mcast pkt getting
                 * queued indicate to the target to set the
                 * BitmapControl LSB of the TIM IE.
                 */
                if (is_mcastq_empty)
                    ath6kl_wmi_set_pvb_cmd(ar->wmi,
                                   vif->fw_vif_idx,
                                   MCAST_AID, 1);

                ps_queued = true;
            } else {
                /*
                 * This transmit is because of Dtim expiry.
                 * Determine if MoreData bit has to be set.
                 */
                spin_lock_bh(&ar->mcastpsq_lock);
                if (!skb_queue_empty(&ar->mcastpsq))
                    *flags |= WMI_DATA_HDR_FLAGS_MORE;
                spin_unlock_bh(&ar->mcastpsq_lock);
            }
        }
    } else {
        conn = ath6kl_find_sta(vif, datap->h_dest);
        if (!conn) {
            dev_kfree_skb(skb);

            /* Inform the caller that the skb is consumed */
            return true;
        }

        if (conn->sta_flags & STA_PS_SLEEP) {
            ps_queued = ath6kl_process_uapsdq(conn,
                        vif, skb, flags);
            if (!(*flags & WMI_DATA_HDR_FLAGS_UAPSD))
                ps_queued = ath6kl_process_psq(conn,
                        vif, skb, flags);
        }
    }
    return ps_queued;
}

/* Tx functions */

int ath6kl_control_tx(void *devt, struct sk_buff *skb,
              enum htc_endpoint_id eid)
{
    struct ath6kl *ar = devt;
    int status = 0;
    struct ath6kl_cookie *cookie = NULL;

    if (WARN_ON_ONCE(ar->state == ATH6KL_STATE_WOW))
        return -EACCES;

    spin_lock_bh(&ar->lock);

    ath6kl_dbg(ATH6KL_DBG_WLAN_TX,
           "%s: skb=0x%p, len=0x%x eid =%d\n", __func__,
           skb, skb->len, eid);

    if (test_bit(WMI_CTRL_EP_FULL, &ar->flag) && (eid == ar->ctrl_ep)) {
        /*
         * Control endpoint is full, don't allocate resources, we
         * are just going to drop this packet.
         */
        cookie = NULL;
        ath6kl_err("wmi ctrl ep full, dropping pkt : 0x%p, len:%d\n",
               skb, skb->len);
    } else
        cookie = ath6kl_alloc_cookie(ar);

    if (cookie == NULL) {
        spin_unlock_bh(&ar->lock);
        status = -ENOMEM;
        goto fail_ctrl_tx;
    }

    ar->tx_pending[eid]++;

    if (eid != ar->ctrl_ep)
        ar->total_tx_data_pend++;

    spin_unlock_bh(&ar->lock);

    cookie->skb = skb;
    cookie->map_no = 0;
    set_htc_pkt_info(&cookie->htc_pkt, cookie, skb->data, skb->len,
             eid, ATH6KL_CONTROL_PKT_TAG);
    cookie->htc_pkt.skb = skb;

    /*
     * This interface is asynchronous, if there is an error, cleanup
     * will happen in the TX completion callback.
     */
    ath6kl_htc_tx(ar->htc_target, &cookie->htc_pkt);

    return 0;

fail_ctrl_tx:
    dev_kfree_skb(skb);
    return status;
}

int ath6kl_data_tx(struct sk_buff *skb, struct net_device *dev)
{
    struct ath6kl *ar = ath6kl_priv(dev);
    struct ath6kl_cookie *cookie = NULL;
    enum htc_endpoint_id eid = ENDPOINT_UNUSED;
    struct ath6kl_vif *vif = netdev_priv(dev);
    u32 map_no = 0;
    u16 htc_tag = ATH6KL_DATA_PKT_TAG;
    u8 ac = 99 ; /* initialize to unmapped ac */
    bool chk_adhoc_ps_mapping = false;
    int ret;
    struct wmi_tx_meta_v2 meta_v2;
    void *meta;
    u8 csum_start = 0, csum_dest = 0, csum = skb->ip_summed;
    u8 meta_ver = 0;
    u32 flags = 0;

    ath6kl_dbg(ATH6KL_DBG_WLAN_TX,
           "%s: skb=0x%p, data=0x%p, len=0x%x\n", __func__,
           skb, skb->data, skb->len);

    /* If target is not associated */
    if (!test_bit(CONNECTED, &vif->flags))
        goto fail_tx;

    if (WARN_ON_ONCE(ar->state != ATH6KL_STATE_ON))
        goto fail_tx;

    if (!test_bit(WMI_READY, &ar->flag))
        goto fail_tx;

    /* AP mode Power saving processing */
    if (vif->nw_type == AP_NETWORK) {
        if (ath6kl_powersave_ap(vif, skb, &flags))
            return 0;
    }

    if (test_bit(WMI_ENABLED, &ar->flag)) {
        if ((dev->features & NETIF_F_IP_CSUM) &&
            (csum == CHECKSUM_PARTIAL)) {
            csum_start = skb->csum_start -
                    (skb_network_header(skb) - skb->head) +
                    sizeof(struct ath6kl_llc_snap_hdr);
            csum_dest = skb->csum_offset + csum_start;
        }

        if (skb_headroom(skb) < dev->needed_headroom) {
            struct sk_buff *tmp_skb = skb;

            skb = skb_realloc_headroom(skb, dev->needed_headroom);
            kfree_skb(tmp_skb);
            if (skb == NULL) {
                vif->net_stats.tx_dropped++;
                return 0;
            }
        }

        if (ath6kl_wmi_dix_2_dot3(ar->wmi, skb)) {
            ath6kl_err("ath6kl_wmi_dix_2_dot3 failed\n");
            goto fail_tx;
        }

        if ((dev->features & NETIF_F_IP_CSUM) &&
            (csum == CHECKSUM_PARTIAL)) {
            meta_v2.csum_start = csum_start;
            meta_v2.csum_dest = csum_dest;

            /* instruct target to calculate checksum */
            meta_v2.csum_flags = WMI_META_V2_FLAG_CSUM_OFFLOAD;
            meta_ver = WMI_META_VERSION_2;
            meta = &meta_v2;
        } else {
            meta_ver = 0;
            meta = NULL;
        }

        ret = ath6kl_wmi_data_hdr_add(ar->wmi, skb,
                DATA_MSGTYPE, flags, 0,
                meta_ver,
                meta, vif->fw_vif_idx);

        if (ret) {
            ath6kl_warn("failed to add wmi data header:%d\n"
                , ret);
            goto fail_tx;
        }

        if ((vif->nw_type == ADHOC_NETWORK) &&
            ar->ibss_ps_enable && test_bit(CONNECTED, &vif->flags))
            chk_adhoc_ps_mapping = true;
        else {
            /* get the stream mapping */
            ret = ath6kl_wmi_implicit_create_pstream(ar->wmi,
                    vif->fw_vif_idx, skb,
                    0, test_bit(WMM_ENABLED, &vif->flags), &ac);
            if (ret)
                goto fail_tx;
        }
    } else
        goto fail_tx;

    spin_lock_bh(&ar->lock);

    if (chk_adhoc_ps_mapping)
        eid = ath6kl_ibss_map_epid(skb, dev, &map_no);
    else
        eid = ar->ac2ep_map[ac];

    if (eid == 0 || eid == ENDPOINT_UNUSED) {
        ath6kl_err("eid %d is not mapped!\n", eid);
        spin_unlock_bh(&ar->lock);
        goto fail_tx;
    }

    /* allocate resource for this packet */
    cookie = ath6kl_alloc_cookie(ar);

    if (!cookie) {
        spin_unlock_bh(&ar->lock);
        goto fail_tx;
    }

    /* update counts while the lock is held */
    ar->tx_pending[eid]++;
    ar->total_tx_data_pend++;

    spin_unlock_bh(&ar->lock);

    if (!IS_ALIGNED((unsigned long) skb->data - HTC_HDR_LENGTH, 4) &&
        skb_cloned(skb)) {
        /*
         * We will touch (move the buffer data to align it. Since the
         * skb buffer is cloned and not only the header is changed, we
         * have to copy it to allow the changes. Since we are copying
         * the data here, we may as well align it by reserving suitable
         * headroom to avoid the memmove in ath6kl_htc_tx_buf_align().
         */
        struct sk_buff *nskb;

        nskb = skb_copy_expand(skb, HTC_HDR_LENGTH, 0, GFP_ATOMIC);
        if (nskb == NULL)
            goto fail_tx;
        kfree_skb(skb);
        skb = nskb;
    }

    cookie->skb = skb;
    cookie->map_no = map_no;
    set_htc_pkt_info(&cookie->htc_pkt, cookie, skb->data, skb->len,
             eid, htc_tag);
    cookie->htc_pkt.skb = skb;

    ath6kl_dbg_dump(ATH6KL_DBG_RAW_BYTES, __func__, "tx ",
            skb->data, skb->len);

    /*
     * HTC interface is asynchronous, if this fails, cleanup will
     * happen in the ath6kl_tx_complete callback.
     */
    ath6kl_htc_tx(ar->htc_target, &cookie->htc_pkt);

    return 0;

fail_tx:
    dev_kfree_skb(skb);

    vif->net_stats.tx_dropped++;
    vif->net_stats.tx_aborted_errors++;

    return 0;
}

/* indicate tx activity or inactivity on a WMI stream */
void ath6kl_indicate_tx_activity(void *devt, u8 traffic_class, bool active)
{
    struct ath6kl *ar = devt;
    enum htc_endpoint_id eid;
    int i;

    eid = ar->ac2ep_map[traffic_class];

    if (!test_bit(WMI_ENABLED, &ar->flag))
        goto notify_htc;

    spin_lock_bh(&ar->lock);

    ar->ac_stream_active[traffic_class] = active;

    if (active) {
        /*
         * Keep track of the active stream with the highest
         * priority.
         */
        if (ar->ac_stream_pri_map[traffic_class] >
            ar->hiac_stream_active_pri)
            /* set the new highest active priority */
            ar->hiac_stream_active_pri =
                    ar->ac_stream_pri_map[traffic_class];

    } else {
        /*
         * We may have to search for the next active stream
         * that is the highest priority.
         */
        if (ar->hiac_stream_active_pri ==
            ar->ac_stream_pri_map[traffic_class]) {
            /*
             * The highest priority stream just went inactive
             * reset and search for the "next" highest "active"
             * priority stream.
             */
            ar->hiac_stream_active_pri = 0;

            for (i = 0; i < WMM_NUM_AC; i++) {
                if (ar->ac_stream_active[i] &&
                    (ar->ac_stream_pri_map[i] >
                     ar->hiac_stream_active_pri))
                    /*
                     * Set the new highest active
                     * priority.
                     */
                    ar->hiac_stream_active_pri =
                        ar->ac_stream_pri_map[i];
            }
        }
    }

    spin_unlock_bh(&ar->lock);

notify_htc:
    /* notify HTC, this may cause credit distribution changes */
    ath6kl_htc_activity_changed(ar->htc_target, eid, active);
}

enum htc_send_full_action ath6kl_tx_queue_full(struct htc_target *target,
                           struct htc_packet *packet)
{
    struct ath6kl *ar = target->dev->ar;
    struct ath6kl_vif *vif;
    enum htc_endpoint_id endpoint = packet->endpoint;
    enum htc_send_full_action action = HTC_SEND_FULL_KEEP;

    if (endpoint == ar->ctrl_ep) {
        /*
         * Under normal WMI if this is getting full, then something
         * is running rampant the host should not be exhausting the
         * WMI queue with too many commands the only exception to
         * this is during testing using endpointping.
         */
        set_bit(WMI_CTRL_EP_FULL, &ar->flag);
        ath6kl_err("wmi ctrl ep is full\n");
        return action;
    }

    if (packet->info.tx.tag == ATH6KL_CONTROL_PKT_TAG)
        return action;

    /*
     * The last MAX_HI_COOKIE_NUM "batch" of cookies are reserved for
     * the highest active stream.
     */
    if (ar->ac_stream_pri_map[ar->ep2ac_map[endpoint]] <
        ar->hiac_stream_active_pri &&
        ar->cookie_count <=
            target->endpoint[endpoint].tx_drop_packet_threshold)
        /*
         * Give preference to the highest priority stream by
         * dropping the packets which overflowed.
         */
        action = HTC_SEND_FULL_DROP;

    /* FIXME: Locking */
    spin_lock_bh(&ar->list_lock);
    list_for_each_entry(vif, &ar->vif_list, list) {
        if (vif->nw_type == ADHOC_NETWORK ||
            action != HTC_SEND_FULL_DROP) {
            spin_unlock_bh(&ar->list_lock);

            set_bit(NETQ_STOPPED, &vif->flags);
            netif_stop_queue(vif->ndev);

            return action;
        }
    }
    spin_unlock_bh(&ar->list_lock);

    return action;
}

/* TODO this needs to be looked at */
static void ath6kl_tx_clear_node_map(struct ath6kl_vif *vif,
                     enum htc_endpoint_id eid, u32 map_no)
{
    struct ath6kl *ar = vif->ar;
    u32 i;

    if (vif->nw_type != ADHOC_NETWORK)
        return;

    if (!ar->ibss_ps_enable)
        return;

    if (eid == ar->ctrl_ep)
        return;

    if (map_no == 0)
        return;

    map_no--;
    ar->node_map[map_no].tx_pend--;

    if (ar->node_map[map_no].tx_pend)
        return;

    if (map_no != (ar->node_num - 1))
        return;

    for (i = ar->node_num; i > 0; i--) {
        if (ar->node_map[i - 1].tx_pend)
            break;

        memset(&ar->node_map[i - 1], 0,
               sizeof(struct ath6kl_node_mapping));
        ar->node_num--;
    }
}

void ath6kl_tx_complete(struct htc_target *target,
            struct list_head *packet_queue)
{
    struct ath6kl *ar = target->dev->ar;
    struct sk_buff_head skb_queue;
    struct htc_packet *packet;
    struct sk_buff *skb;
    struct ath6kl_cookie *ath6kl_cookie;
    u32 map_no = 0;
    int status;
    enum htc_endpoint_id eid;
    bool wake_event = false;
    bool flushing[ATH6KL_VIF_MAX] = {false};
    u8 if_idx;
    struct ath6kl_vif *vif;

    skb_queue_head_init(&skb_queue);

    /* lock the driver as we update internal state */
    spin_lock_bh(&ar->lock);

    /* reap completed packets */
    while (!list_empty(packet_queue)) {

        packet = list_first_entry(packet_queue, struct htc_packet,
                      list);
        list_del(&packet->list);

        ath6kl_cookie = (struct ath6kl_cookie *)packet->pkt_cntxt;
        if (!ath6kl_cookie)
            goto fatal;

        status = packet->status;
        skb = ath6kl_cookie->skb;
        eid = packet->endpoint;
        map_no = ath6kl_cookie->map_no;

        if (!skb || !skb->data)
            goto fatal;

        __skb_queue_tail(&skb_queue, skb);

        if (!status && (packet->act_len != skb->len))
            goto fatal;

        ar->tx_pending[eid]--;

        if (eid != ar->ctrl_ep)
            ar->total_tx_data_pend--;

        if (eid == ar->ctrl_ep) {
            if (test_bit(WMI_CTRL_EP_FULL, &ar->flag))
                clear_bit(WMI_CTRL_EP_FULL, &ar->flag);

            if (ar->tx_pending[eid] == 0)
                wake_event = true;
        }

        if (eid == ar->ctrl_ep) {
            if_idx = wmi_cmd_hdr_get_if_idx(
                (struct wmi_cmd_hdr *) packet->buf);
        } else {
            if_idx = wmi_data_hdr_get_if_idx(
                (struct wmi_data_hdr *) packet->buf);
        }

        vif = ath6kl_get_vif_by_index(ar, if_idx);
        if (!vif) {
            ath6kl_free_cookie(ar, ath6kl_cookie);
            continue;
        }

        if (status) {
            if (status == -ECANCELED)
                /* a packet was flushed  */
                flushing[if_idx] = true;

            vif->net_stats.tx_errors++;

            if (status != -ENOSPC && status != -ECANCELED)
                ath6kl_warn("tx complete error: %d\n", status);

            ath6kl_dbg(ATH6KL_DBG_WLAN_TX,
                   "%s: skb=0x%p data=0x%p len=0x%x eid=%d %s\n",
                   __func__, skb, packet->buf, packet->act_len,
                   eid, "error!");
        } else {
            ath6kl_dbg(ATH6KL_DBG_WLAN_TX,
                   "%s: skb=0x%p data=0x%p len=0x%x eid=%d %s\n",
                   __func__, skb, packet->buf, packet->act_len,
                   eid, "OK");

            flushing[if_idx] = false;
            vif->net_stats.tx_packets++;
            vif->net_stats.tx_bytes += skb->len;
        }

        ath6kl_tx_clear_node_map(vif, eid, map_no);

        ath6kl_free_cookie(ar, ath6kl_cookie);

        if (test_bit(NETQ_STOPPED, &vif->flags))
            clear_bit(NETQ_STOPPED, &vif->flags);
    }

    spin_unlock_bh(&ar->lock);

    __skb_queue_purge(&skb_queue);

    /* FIXME: Locking */
    spin_lock_bh(&ar->list_lock);
    list_for_each_entry(vif, &ar->vif_list, list) {
        if (test_bit(CONNECTED, &vif->flags) &&
            !flushing[vif->fw_vif_idx]) {
            spin_unlock_bh(&ar->list_lock);
            netif_wake_queue(vif->ndev);
            spin_lock_bh(&ar->list_lock);
        }
    }
    spin_unlock_bh(&ar->list_lock);

    if (wake_event)
        wake_up(&ar->event_wq);

    return;

fatal:
    WARN_ON(1);
    spin_unlock_bh(&ar->lock);
    return;
}

void ath6kl_tx_data_cleanup(struct ath6kl *ar)
{
    int i;

    /* flush all the data (non-control) streams */
    for (i = 0; i < WMM_NUM_AC; i++)
        ath6kl_htc_flush_txep(ar->htc_target, ar->ac2ep_map[i],
                      ATH6KL_DATA_PKT_TAG);
}

/* Rx functions */

static void ath6kl_deliver_frames_to_nw_stack(struct net_device *dev,
                          struct sk_buff *skb)
{
    if (!skb)
        return;

    skb->dev = dev;

    if (!(skb->dev->flags & IFF_UP)) {
        dev_kfree_skb(skb);
        return;
    }

    skb->protocol = eth_type_trans(skb, skb->dev);

    netif_rx_ni(skb);
}

static void ath6kl_alloc_netbufs(struct sk_buff_head *q, u16 num)
{
    struct sk_buff *skb;

    while (num) {
        skb = ath6kl_buf_alloc(ATH6KL_BUFFER_SIZE);
        if (!skb) {
            ath6kl_err("netbuf allocation failed\n");
            return;
        }
        skb_queue_tail(q, skb);
        num--;
    }
}

static struct sk_buff *aggr_get_free_skb(struct aggr_info *p_aggr)
{
    struct sk_buff *skb = NULL;

    if (skb_queue_len(&p_aggr->rx_amsdu_freeq) <
        (AGGR_NUM_OF_FREE_NETBUFS >> 2))
        ath6kl_alloc_netbufs(&p_aggr->rx_amsdu_freeq,
                     AGGR_NUM_OF_FREE_NETBUFS);

    skb = skb_dequeue(&p_aggr->rx_amsdu_freeq);

    return skb;
}

void ath6kl_rx_refill(struct htc_target *target, enum htc_endpoint_id endpoint)
{
    struct ath6kl *ar = target->dev->ar;
    struct sk_buff *skb;
    int rx_buf;
    int n_buf_refill;
    struct htc_packet *packet;
    struct list_head queue;

    n_buf_refill = ATH6KL_MAX_RX_BUFFERS -
              ath6kl_htc_get_rxbuf_num(ar->htc_target, endpoint);

    if (n_buf_refill <= 0)
        return;

    INIT_LIST_HEAD(&queue);

    ath6kl_dbg(ATH6KL_DBG_WLAN_RX,
           "%s: providing htc with %d buffers at eid=%d\n",
           __func__, n_buf_refill, endpoint);

    for (rx_buf = 0; rx_buf < n_buf_refill; rx_buf++) {
        skb = ath6kl_buf_alloc(ATH6KL_BUFFER_SIZE);
        if (!skb)
            break;

        packet = (struct htc_packet *) skb->head;
        if (!IS_ALIGNED((unsigned long) skb->data, 4))
            skb->data = PTR_ALIGN(skb->data - 4, 4);
        set_htc_rxpkt_info(packet, skb, skb->data,
                   ATH6KL_BUFFER_SIZE, endpoint);
        packet->skb = skb;
        list_add_tail(&packet->list, &queue);
    }

    if (!list_empty(&queue))
        ath6kl_htc_add_rxbuf_multiple(ar->htc_target, &queue);
}

void ath6kl_refill_amsdu_rxbufs(struct ath6kl *ar, int count)
{
    struct htc_packet *packet;
    struct sk_buff *skb;

    while (count) {
        skb = ath6kl_buf_alloc(ATH6KL_AMSDU_BUFFER_SIZE);
        if (!skb)
            return;

        packet = (struct htc_packet *) skb->head;
        if (!IS_ALIGNED((unsigned long) skb->data, 4))
            skb->data = PTR_ALIGN(skb->data - 4, 4);
        set_htc_rxpkt_info(packet, skb, skb->data,
                   ATH6KL_AMSDU_BUFFER_SIZE, 0);
        packet->skb = skb;

        spin_lock_bh(&ar->lock);
        list_add_tail(&packet->list, &ar->amsdu_rx_buffer_queue);
        spin_unlock_bh(&ar->lock);
        count--;
    }
}

/*
 * Callback to allocate a receive buffer for a pending packet. We use a
 * pre-allocated list of buffers of maximum AMSDU size (4K).
 */
struct htc_packet *ath6kl_alloc_amsdu_rxbuf(struct htc_target *target,
                        enum htc_endpoint_id endpoint,
                        int len)
{
    struct ath6kl *ar = target->dev->ar;
    struct htc_packet *packet = NULL;
    struct list_head *pkt_pos;
    int refill_cnt = 0, depth = 0;

    ath6kl_dbg(ATH6KL_DBG_WLAN_RX, "%s: eid=%d, len:%d\n",
           __func__, endpoint, len);

    if ((len <= ATH6KL_BUFFER_SIZE) ||
        (len > ATH6KL_AMSDU_BUFFER_SIZE))
        return NULL;

    spin_lock_bh(&ar->lock);

    if (list_empty(&ar->amsdu_rx_buffer_queue)) {
        spin_unlock_bh(&ar->lock);
        refill_cnt = ATH6KL_MAX_AMSDU_RX_BUFFERS;
        goto refill_buf;
    }

    packet = list_first_entry(&ar->amsdu_rx_buffer_queue,
                  struct htc_packet, list);
    list_del(&packet->list);
    list_for_each(pkt_pos, &ar->amsdu_rx_buffer_queue)
        depth++;

    refill_cnt = ATH6KL_MAX_AMSDU_RX_BUFFERS - depth;
    spin_unlock_bh(&ar->lock);

    /* set actual endpoint ID */
    packet->endpoint = endpoint;

refill_buf:
    if (refill_cnt >= ATH6KL_AMSDU_REFILL_THRESHOLD)
        ath6kl_refill_amsdu_rxbufs(ar, refill_cnt);

    return packet;
}

static void aggr_slice_amsdu(struct aggr_info *p_aggr,
                 struct rxtid *rxtid, struct sk_buff *skb)
{
    struct sk_buff *new_skb;
    struct ethhdr *hdr;
    u16 frame_8023_len, payload_8023_len, mac_hdr_len, amsdu_len;
    u8 *framep;

    mac_hdr_len = sizeof(struct ethhdr);
    framep = skb->data + mac_hdr_len;
    amsdu_len = skb->len - mac_hdr_len;

    while (amsdu_len > mac_hdr_len) {
        hdr = (struct ethhdr *) framep;
        payload_8023_len = ntohs(hdr->h_proto);

        if (payload_8023_len < MIN_MSDU_SUBFRAME_PAYLOAD_LEN ||
            payload_8023_len > MAX_MSDU_SUBFRAME_PAYLOAD_LEN) {
            ath6kl_err("802.3 AMSDU frame bound check failed. len %d\n",
                   payload_8023_len);
            break;
        }

        frame_8023_len = payload_8023_len + mac_hdr_len;
        new_skb = aggr_get_free_skb(p_aggr);
        if (!new_skb) {
            ath6kl_err("no buffer available\n");
            break;
        }

        memcpy(new_skb->data, framep, frame_8023_len);
        skb_put(new_skb, frame_8023_len);
        if (ath6kl_wmi_dot3_2_dix(new_skb)) {
            ath6kl_err("dot3_2_dix error\n");
            dev_kfree_skb(new_skb);
            break;
        }

        skb_queue_tail(&rxtid->q, new_skb);

        /* Is this the last subframe within this aggregate ? */
        if ((amsdu_len - frame_8023_len) == 0)
            break;

        /* Add the length of A-MSDU subframe padding bytes -
         * Round to nearest word.
         */
        frame_8023_len = ALIGN(frame_8023_len, 4);

        framep += frame_8023_len;
        amsdu_len -= frame_8023_len;
    }

    dev_kfree_skb(skb);
}

static void aggr_deque_frms(struct aggr_info_conn *agg_conn, u8 tid,
                u16 seq_no, u8 order)
{
    struct sk_buff *skb;
    struct rxtid *rxtid;
    struct skb_hold_q *node;
    u16 idx, idx_end, seq_end;
    struct rxtid_stats *stats;

    rxtid = &agg_conn->rx_tid[tid];
    stats = &agg_conn->stat[tid];

    spin_lock_bh(&rxtid->lock);
    idx = AGGR_WIN_IDX(rxtid->seq_next, rxtid->hold_q_sz);

    /*
     * idx_end is typically the last possible frame in the window,
     * but changes to 'the' seq_no, when BAR comes. If seq_no
     * is non-zero, we will go up to that and stop.
     * Note: last seq no in current window will occupy the same
     * index position as index that is just previous to start.
     * An imp point : if win_sz is 7, for seq_no space of 4095,
     * then, there would be holes when sequence wrap around occurs.
     * Target should judiciously choose the win_sz, based on
     * this condition. For 4095, (TID_WINDOW_SZ = 2 x win_sz
     * 2, 4, 8, 16 win_sz works fine).
     * We must deque from "idx" to "idx_end", including both.
     */
    seq_end = seq_no ? seq_no : rxtid->seq_next;
    idx_end = AGGR_WIN_IDX(seq_end, rxtid->hold_q_sz);

    do {
        node = &rxtid->hold_q[idx];
        if ((order == 1) && (!node->skb))
            break;

        if (node->skb) {
            if (node->is_amsdu)
                aggr_slice_amsdu(agg_conn->aggr_info, rxtid,
                         node->skb);
            else
                skb_queue_tail(&rxtid->q, node->skb);
            node->skb = NULL;
        } else
            stats->num_hole++;

        rxtid->seq_next = ATH6KL_NEXT_SEQ_NO(rxtid->seq_next);
        idx = AGGR_WIN_IDX(rxtid->seq_next, rxtid->hold_q_sz);
    } while (idx != idx_end);

    spin_unlock_bh(&rxtid->lock);

    stats->num_delivered += skb_queue_len(&rxtid->q);

    while ((skb = skb_dequeue(&rxtid->q)))
        ath6kl_deliver_frames_to_nw_stack(agg_conn->dev, skb);
}

static bool aggr_process_recv_frm(struct aggr_info_conn *agg_conn, u8 tid,
                  u16 seq_no,
                  bool is_amsdu, struct sk_buff *frame)
{
    struct rxtid *rxtid;
    struct rxtid_stats *stats;
    struct sk_buff *skb;
    struct skb_hold_q *node;
    u16 idx, st, cur, end;
    bool is_queued = false;
    u16 extended_end;

    rxtid = &agg_conn->rx_tid[tid];
    stats = &agg_conn->stat[tid];

    stats->num_into_aggr++;

    if (!rxtid->aggr) {
        if (is_amsdu) {
            aggr_slice_amsdu(agg_conn->aggr_info, rxtid, frame);
            is_queued = true;
            stats->num_amsdu++;
            while ((skb = skb_dequeue(&rxtid->q)))
                ath6kl_deliver_frames_to_nw_stack(agg_conn->dev,
                                  skb);
        }
        return is_queued;
    }

    /* Check the incoming sequence no, if it's in the window */
    st = rxtid->seq_next;
    cur = seq_no;
    end = (st + rxtid->hold_q_sz-1) & ATH6KL_MAX_SEQ_NO;

    if (((st < end) && (cur < st || cur > end)) ||
        ((st > end) && (cur > end) && (cur < st))) {
        extended_end = (end + rxtid->hold_q_sz - 1) &
            ATH6KL_MAX_SEQ_NO;

        if (((end < extended_end) &&
             (cur < end || cur > extended_end)) ||
            ((end > extended_end) && (cur > extended_end) &&
             (cur < end))) {
            aggr_deque_frms(agg_conn, tid, 0, 0);
            spin_lock_bh(&rxtid->lock);
            if (cur >= rxtid->hold_q_sz - 1)
                rxtid->seq_next = cur - (rxtid->hold_q_sz - 1);
            else
                rxtid->seq_next = ATH6KL_MAX_SEQ_NO -
                          (rxtid->hold_q_sz - 2 - cur);
            spin_unlock_bh(&rxtid->lock);
        } else {
            /*
             * Dequeue only those frames that are outside the
             * new shifted window.
             */
            if (cur >= rxtid->hold_q_sz - 1)
                st = cur - (rxtid->hold_q_sz - 1);
            else
                st = ATH6KL_MAX_SEQ_NO -
                    (rxtid->hold_q_sz - 2 - cur);

            aggr_deque_frms(agg_conn, tid, st, 0);
        }

        stats->num_oow++;
    }

    idx = AGGR_WIN_IDX(seq_no, rxtid->hold_q_sz);

    node = &rxtid->hold_q[idx];

    spin_lock_bh(&rxtid->lock);

    /*
     * Is the cur frame duplicate or something beyond our window(hold_q
     * -> which is 2x, already)?
     *
     * 1. Duplicate is easy - drop incoming frame.
     * 2. Not falling in current sliding window.
     *  2a. is the frame_seq_no preceding current tid_seq_no?
     *      -> drop the frame. perhaps sender did not get our ACK.
     *         this is taken care of above.
     *  2b. is the frame_seq_no beyond window(st, TID_WINDOW_SZ);
     *      -> Taken care of it above, by moving window forward.
     */
    dev_kfree_skb(node->skb);
    stats->num_dups++;

    node->skb = frame;
    is_queued = true;
    node->is_amsdu = is_amsdu;
    node->seq_no = seq_no;

    if (node->is_amsdu)
        stats->num_amsdu++;
    else
        stats->num_mpdu++;

    spin_unlock_bh(&rxtid->lock);

    aggr_deque_frms(agg_conn, tid, 0, 1);

    if (agg_conn->timer_scheduled)
        return is_queued;

    spin_lock_bh(&rxtid->lock);
    for (idx = 0 ; idx < rxtid->hold_q_sz; idx++) {
        if (rxtid->hold_q[idx].skb) {
            /*
             * There is a frame in the queue and no
             * timer so start a timer to ensure that
             * the frame doesn't remain stuck
             * forever.
             */
            agg_conn->timer_scheduled = true;
            mod_timer(&agg_conn->timer,
                  (jiffies + (HZ * AGGR_RX_TIMEOUT) / 1000));
            rxtid->timer_mon = true;
            break;
        }
    }
    spin_unlock_bh(&rxtid->lock);

    return is_queued;
}

static void ath6kl_uapsd_trigger_frame_rx(struct ath6kl_vif *vif,
                         struct ath6kl_sta *conn)
{
    struct ath6kl *ar = vif->ar;
    bool is_apsdq_empty, is_apsdq_empty_at_start;
    u32 num_frames_to_deliver, flags;
    struct sk_buff *skb = NULL;

    /*
     * If the APSD q for this STA is not empty, dequeue and
     * send a pkt from the head of the q. Also update the
     * More data bit in the WMI_DATA_HDR if there are
     * more pkts for this STA in the APSD q.
     * If there are no more pkts for this STA,
     * update the APSD bitmap for this STA.
     */

    num_frames_to_deliver = (conn->apsd_info >> ATH6KL_APSD_NUM_OF_AC) &
                            ATH6KL_APSD_FRAME_MASK;
    /*
     * Number of frames to send in a service period is
     * indicated by the station
     * in the QOS_INFO of the association request
     * If it is zero, send all frames
     */
    if (!num_frames_to_deliver)
        num_frames_to_deliver = ATH6KL_APSD_ALL_FRAME;

    spin_lock_bh(&conn->psq_lock);
    is_apsdq_empty = skb_queue_empty(&conn->apsdq);
    spin_unlock_bh(&conn->psq_lock);
    is_apsdq_empty_at_start = is_apsdq_empty;

    while ((!is_apsdq_empty) && (num_frames_to_deliver)) {

        spin_lock_bh(&conn->psq_lock);
        skb = skb_dequeue(&conn->apsdq);
        is_apsdq_empty = skb_queue_empty(&conn->apsdq);
        spin_unlock_bh(&conn->psq_lock);

        /*
         * Set the STA flag to Trigger delivery,
         * so that the frame will go out
         */
        conn->sta_flags |= STA_PS_APSD_TRIGGER;
        num_frames_to_deliver--;

        /* Last frame in the service period, set EOSP or queue empty */
        if ((is_apsdq_empty) || (!num_frames_to_deliver))
            conn->sta_flags |= STA_PS_APSD_EOSP;

        ath6kl_data_tx(skb, vif->ndev);
        conn->sta_flags &= ~(STA_PS_APSD_TRIGGER);
        conn->sta_flags &= ~(STA_PS_APSD_EOSP);
    }

    if (is_apsdq_empty) {
        if (is_apsdq_empty_at_start)
            flags = WMI_AP_APSD_NO_DELIVERY_FRAMES;
        else
            flags = 0;

        ath6kl_wmi_set_apsd_bfrd_traf(ar->wmi,
                          vif->fw_vif_idx,
                          conn->aid, 0, flags);
    }

    return;
}

void ath6kl_rx(struct htc_target *target, struct htc_packet *packet)
{
    struct ath6kl *ar = target->dev->ar;
    struct sk_buff *skb = packet->pkt_cntxt;
    struct wmi_rx_meta_v2 *meta;
    struct wmi_data_hdr *dhdr;
    int min_hdr_len;
    u8 meta_type, dot11_hdr = 0;
    u8 pad_before_data_start;
    int status = packet->status;
    enum htc_endpoint_id ept = packet->endpoint;
    bool is_amsdu, prev_ps, ps_state = false;
    bool trig_state = false;
    struct ath6kl_sta *conn = NULL;
    struct sk_buff *skb1 = NULL;
    struct ethhdr *datap = NULL;
    struct ath6kl_vif *vif;
    struct aggr_info_conn *aggr_conn;
    u16 seq_no, offset;
    u8 tid, if_idx;

    ath6kl_dbg(ATH6KL_DBG_WLAN_RX,
           "%s: ar=0x%p eid=%d, skb=0x%p, data=0x%p, len=0x%x status:%d",
           __func__, ar, ept, skb, packet->buf,
           packet->act_len, status);

    if (status || !(skb->data + HTC_HDR_LENGTH)) {
        dev_kfree_skb(skb);
        return;
    }

    skb_put(skb, packet->act_len + HTC_HDR_LENGTH);
    skb_pull(skb, HTC_HDR_LENGTH);

    ath6kl_dbg_dump(ATH6KL_DBG_RAW_BYTES, __func__, "rx ",
            skb->data, skb->len);

    if (ept == ar->ctrl_ep) {
        if (test_bit(WMI_ENABLED, &ar->flag)) {
            ath6kl_check_wow_status(ar);
            ath6kl_wmi_control_rx(ar->wmi, skb);
            return;
        }
        if_idx =
        wmi_cmd_hdr_get_if_idx((struct wmi_cmd_hdr *) skb->data);
    } else {
        if_idx =
        wmi_data_hdr_get_if_idx((struct wmi_data_hdr *) skb->data);
    }

    vif = ath6kl_get_vif_by_index(ar, if_idx);
    if (!vif) {
        dev_kfree_skb(skb);
        return;
    }

    /*
     * Take lock to protect buffer counts and adaptive power throughput
     * state.
     */
    spin_lock_bh(&vif->if_lock);

    vif->net_stats.rx_packets++;
    vif->net_stats.rx_bytes += packet->act_len;

    spin_unlock_bh(&vif->if_lock);

    skb->dev = vif->ndev;

    if (!test_bit(WMI_ENABLED, &ar->flag)) {
        if (EPPING_ALIGNMENT_PAD > 0)
            skb_pull(skb, EPPING_ALIGNMENT_PAD);
        ath6kl_deliver_frames_to_nw_stack(vif->ndev, skb);
        return;
    }

    ath6kl_check_wow_status(ar);

    min_hdr_len = sizeof(struct ethhdr) + sizeof(struct wmi_data_hdr) +
              sizeof(struct ath6kl_llc_snap_hdr);

    dhdr = (struct wmi_data_hdr *) skb->data;

    /*
     * In the case of AP mode we may receive NULL data frames
     * that do not have LLC hdr. They are 16 bytes in size.
     * Allow these frames in the AP mode.
     */
    if (vif->nw_type != AP_NETWORK &&
        ((packet->act_len < min_hdr_len) ||
         (packet->act_len > WMI_MAX_AMSDU_RX_DATA_FRAME_LENGTH))) {
        ath6kl_info("frame len is too short or too long\n");
        vif->net_stats.rx_errors++;
        vif->net_stats.rx_length_errors++;
        dev_kfree_skb(skb);
        return;
    }

    /* Get the Power save state of the STA */
    if (vif->nw_type == AP_NETWORK) {
        meta_type = wmi_data_hdr_get_meta(dhdr);

        ps_state = !!((dhdr->info >> WMI_DATA_HDR_PS_SHIFT) &
                  WMI_DATA_HDR_PS_MASK);

        offset = sizeof(struct wmi_data_hdr);
        trig_state = !!(le16_to_cpu(dhdr->info3) & WMI_DATA_HDR_TRIG);

        switch (meta_type) {
        case 0:
            break;
        case WMI_META_VERSION_1:
            offset += sizeof(struct wmi_rx_meta_v1);
            break;
        case WMI_META_VERSION_2:
            offset += sizeof(struct wmi_rx_meta_v2);
            break;
        default:
            break;
        }

        datap = (struct ethhdr *) (skb->data + offset);
        conn = ath6kl_find_sta(vif, datap->h_source);

        if (!conn) {
            dev_kfree_skb(skb);
            return;
        }

        /*
         * If there is a change in PS state of the STA,
         * take appropriate steps:
         *
         * 1. If Sleep-->Awake, flush the psq for the STA
         *    Clear the PVB for the STA.
         * 2. If Awake-->Sleep, Starting queueing frames
         *    the STA.
         */
        prev_ps = !!(conn->sta_flags & STA_PS_SLEEP);

        if (ps_state)
            conn->sta_flags |= STA_PS_SLEEP;
        else
            conn->sta_flags &= ~STA_PS_SLEEP;

        /* Accept trigger only when the station is in sleep */
        if ((conn->sta_flags & STA_PS_SLEEP) && trig_state)
            ath6kl_uapsd_trigger_frame_rx(vif, conn);

        if (prev_ps ^ !!(conn->sta_flags & STA_PS_SLEEP)) {
            if (!(conn->sta_flags & STA_PS_SLEEP)) {
                struct sk_buff *skbuff = NULL;
                bool is_apsdq_empty;
                struct ath6kl_mgmt_buff *mgmt;
                u8 idx;

                spin_lock_bh(&conn->psq_lock);
                while (conn->mgmt_psq_len > 0) {
                    mgmt = list_first_entry(
                            &conn->mgmt_psq,
                            struct ath6kl_mgmt_buff,
                            list);
                    list_del(&mgmt->list);
                    conn->mgmt_psq_len--;
                    spin_unlock_bh(&conn->psq_lock);
                    idx = vif->fw_vif_idx;

                    ath6kl_wmi_send_mgmt_cmd(ar->wmi,
                                 idx,
                                 mgmt->id,
                                 mgmt->freq,
                                 mgmt->wait,
                                 mgmt->buf,
                                 mgmt->len,
                                 mgmt->no_cck);

                    kfree(mgmt);
                    spin_lock_bh(&conn->psq_lock);
                }
                conn->mgmt_psq_len = 0;
                while ((skbuff = skb_dequeue(&conn->psq))) {
                    spin_unlock_bh(&conn->psq_lock);
                    ath6kl_data_tx(skbuff, vif->ndev);
                    spin_lock_bh(&conn->psq_lock);
                }

                is_apsdq_empty = skb_queue_empty(&conn->apsdq);
                while ((skbuff = skb_dequeue(&conn->apsdq))) {
                    spin_unlock_bh(&conn->psq_lock);
                    ath6kl_data_tx(skbuff, vif->ndev);
                    spin_lock_bh(&conn->psq_lock);
                }
                spin_unlock_bh(&conn->psq_lock);

                if (!is_apsdq_empty)
                    ath6kl_wmi_set_apsd_bfrd_traf(
                            ar->wmi,
                            vif->fw_vif_idx,
                            conn->aid, 0, 0);

                /* Clear the PVB for this STA */
                ath6kl_wmi_set_pvb_cmd(ar->wmi, vif->fw_vif_idx,
                               conn->aid, 0);
            }
        }

        /* drop NULL data frames here */
        if ((packet->act_len < min_hdr_len) ||
            (packet->act_len >
             WMI_MAX_AMSDU_RX_DATA_FRAME_LENGTH)) {
            dev_kfree_skb(skb);
            return;
        }
    }

    is_amsdu = wmi_data_hdr_is_amsdu(dhdr) ? true : false;
    tid = wmi_data_hdr_get_up(dhdr);
    seq_no = wmi_data_hdr_get_seqno(dhdr);
    meta_type = wmi_data_hdr_get_meta(dhdr);
    dot11_hdr = wmi_data_hdr_get_dot11(dhdr);
    pad_before_data_start =
        (le16_to_cpu(dhdr->info3) >> WMI_DATA_HDR_PAD_BEFORE_DATA_SHIFT)
            & WMI_DATA_HDR_PAD_BEFORE_DATA_MASK;

    skb_pull(skb, sizeof(struct wmi_data_hdr));

    switch (meta_type) {
    case WMI_META_VERSION_1:
        skb_pull(skb, sizeof(struct wmi_rx_meta_v1));
        break;
    case WMI_META_VERSION_2:
        meta = (struct wmi_rx_meta_v2 *) skb->data;
        if (meta->csum_flags & 0x1) {
            skb->ip_summed = CHECKSUM_COMPLETE;
            skb->csum = (__force __wsum) meta->csum;
        }
        skb_pull(skb, sizeof(struct wmi_rx_meta_v2));
        break;
    default:
        break;
    }

    skb_pull(skb, pad_before_data_start);

    if (dot11_hdr)
        status = ath6kl_wmi_dot11_hdr_remove(ar->wmi, skb);
    else if (!is_amsdu)
        status = ath6kl_wmi_dot3_2_dix(skb);

    if (status) {
        /*
         * Drop frames that could not be processed (lack of
         * memory, etc.)
         */
        dev_kfree_skb(skb);
        return;
    }

    if (!(vif->ndev->flags & IFF_UP)) {
        dev_kfree_skb(skb);
        return;
    }

    if (vif->nw_type == AP_NETWORK) {
        datap = (struct ethhdr *) skb->data;
        if (is_multicast_ether_addr(datap->h_dest))
            /*
             * Bcast/Mcast frames should be sent to the
             * OS stack as well as on the air.
             */
            skb1 = skb_copy(skb, GFP_ATOMIC);
        else {
            /*
             * Search for a connected STA with dstMac
             * as the Mac address. If found send the
             * frame to it on the air else send the
             * frame up the stack.
             */
            conn = ath6kl_find_sta(vif, datap->h_dest);

            if (conn && ar->intra_bss) {
                skb1 = skb;
                skb = NULL;
            } else if (conn && !ar->intra_bss) {
                dev_kfree_skb(skb);
                skb = NULL;
            }
        }
        if (skb1)
            ath6kl_data_tx(skb1, vif->ndev);

        if (skb == NULL) {
            /* nothing to deliver up the stack */
            return;
        }
    }

    datap = (struct ethhdr *) skb->data;

    if (is_unicast_ether_addr(datap->h_dest)) {
        if (vif->nw_type == AP_NETWORK) {
            conn = ath6kl_find_sta(vif, datap->h_source);
            if (!conn)
                return;
            aggr_conn = conn->aggr_conn;
        } else
            aggr_conn = vif->aggr_cntxt->aggr_conn;

        if (aggr_process_recv_frm(aggr_conn, tid, seq_no,
                      is_amsdu, skb)) {
            /* aggregation code will handle the skb */
            return;
        }
    } else if (!is_broadcast_ether_addr(datap->h_dest))
        vif->net_stats.multicast++;

    ath6kl_deliver_frames_to_nw_stack(vif->ndev, skb);
}

static void aggr_timeout(unsigned long arg)
{
    u8 i, j;
    struct aggr_info_conn *aggr_conn = (struct aggr_info_conn *) arg;
    struct rxtid *rxtid;
    struct rxtid_stats *stats;

    for (i = 0; i < NUM_OF_TIDS; i++) {
        rxtid = &aggr_conn->rx_tid[i];
        stats = &aggr_conn->stat[i];

        if (!rxtid->aggr || !rxtid->timer_mon)
            continue;

        stats->num_timeouts++;
        ath6kl_dbg(ATH6KL_DBG_AGGR,
               "aggr timeout (st %d end %d)\n",
               rxtid->seq_next,
               ((rxtid->seq_next + rxtid->hold_q_sz-1) &
                ATH6KL_MAX_SEQ_NO));
        aggr_deque_frms(aggr_conn, i, 0, 0);
    }

    aggr_conn->timer_scheduled = false;

    for (i = 0; i < NUM_OF_TIDS; i++) {
        rxtid = &aggr_conn->rx_tid[i];

        if (rxtid->aggr && rxtid->hold_q) {
            spin_lock_bh(&rxtid->lock);
            for (j = 0; j < rxtid->hold_q_sz; j++) {
                if (rxtid->hold_q[j].skb) {
                    aggr_conn->timer_scheduled = true;
                    rxtid->timer_mon = true;
                    break;
                }
            }
            spin_unlock_bh(&rxtid->lock);

            if (j >= rxtid->hold_q_sz)
                rxtid->timer_mon = false;
        }
    }

    if (aggr_conn->timer_scheduled)
        mod_timer(&aggr_conn->timer,
              jiffies + msecs_to_jiffies(AGGR_RX_TIMEOUT));
}

static void aggr_delete_tid_state(struct aggr_info_conn *aggr_conn, u8 tid)
{
    struct rxtid *rxtid;
    struct rxtid_stats *stats;

    if (!aggr_conn || tid >= NUM_OF_TIDS)
        return;

    rxtid = &aggr_conn->rx_tid[tid];
    stats = &aggr_conn->stat[tid];

    if (rxtid->aggr)
        aggr_deque_frms(aggr_conn, tid, 0, 0);

    rxtid->aggr = false;
    rxtid->timer_mon = false;
    rxtid->win_sz = 0;
    rxtid->seq_next = 0;
    rxtid->hold_q_sz = 0;

    kfree(rxtid->hold_q);
    rxtid->hold_q = NULL;

    memset(stats, 0, sizeof(struct rxtid_stats));
}

void aggr_recv_addba_req_evt(struct ath6kl_vif *vif, u8 tid_mux, u16 seq_no,
                 u8 win_sz)
{
    struct ath6kl_sta *sta;
    struct aggr_info_conn *aggr_conn = NULL;
    struct rxtid *rxtid;
    struct rxtid_stats *stats;
    u16 hold_q_size;
    u8 tid, aid;

    if (vif->nw_type == AP_NETWORK) {
        aid = ath6kl_get_aid(tid_mux);
        sta = ath6kl_find_sta_by_aid(vif->ar, aid);
        if (sta)
            aggr_conn = sta->aggr_conn;
    } else
        aggr_conn = vif->aggr_cntxt->aggr_conn;

    if (!aggr_conn)
        return;

    tid = ath6kl_get_tid(tid_mux);
    if (tid >= NUM_OF_TIDS)
        return;

    rxtid = &aggr_conn->rx_tid[tid];
    stats = &aggr_conn->stat[tid];

    if (win_sz < AGGR_WIN_SZ_MIN || win_sz > AGGR_WIN_SZ_MAX)
        ath6kl_dbg(ATH6KL_DBG_WLAN_RX, "%s: win_sz %d, tid %d\n",
               __func__, win_sz, tid);

    if (rxtid->aggr)
        aggr_delete_tid_state(aggr_conn, tid);

    rxtid->seq_next = seq_no;
    hold_q_size = TID_WINDOW_SZ(win_sz) * sizeof(struct skb_hold_q);
    rxtid->hold_q = kzalloc(hold_q_size, GFP_KERNEL);
    if (!rxtid->hold_q)
        return;

    rxtid->win_sz = win_sz;
    rxtid->hold_q_sz = TID_WINDOW_SZ(win_sz);
    if (!skb_queue_empty(&rxtid->q))
        return;

    rxtid->aggr = true;
}

void aggr_conn_init(struct ath6kl_vif *vif, struct aggr_info *aggr_info,
            struct aggr_info_conn *aggr_conn)
{
    struct rxtid *rxtid;
    u8 i;

    aggr_conn->aggr_sz = AGGR_SZ_DEFAULT;
    aggr_conn->dev = vif->ndev;
    init_timer(&aggr_conn->timer);
    aggr_conn->timer.function = aggr_timeout;
    aggr_conn->timer.data = (unsigned long) aggr_conn;
    aggr_conn->aggr_info = aggr_info;

    aggr_conn->timer_scheduled = false;

    for (i = 0; i < NUM_OF_TIDS; i++) {
        rxtid = &aggr_conn->rx_tid[i];
        rxtid->aggr = false;
        rxtid->timer_mon = false;
        skb_queue_head_init(&rxtid->q);
        spin_lock_init(&rxtid->lock);
    }

}

struct aggr_info *aggr_init(struct ath6kl_vif *vif)
{
    struct aggr_info *p_aggr = NULL;

    p_aggr = kzalloc(sizeof(struct aggr_info), GFP_KERNEL);
    if (!p_aggr) {
        ath6kl_err("failed to alloc memory for aggr_node\n");
        return NULL;
    }

    p_aggr->aggr_conn = kzalloc(sizeof(struct aggr_info_conn), GFP_KERNEL);
    if (!p_aggr->aggr_conn) {
        ath6kl_err("failed to alloc memory for connection specific aggr info\n");
        kfree(p_aggr);
        return NULL;
    }

    aggr_conn_init(vif, p_aggr, p_aggr->aggr_conn);

    skb_queue_head_init(&p_aggr->rx_amsdu_freeq);
    ath6kl_alloc_netbufs(&p_aggr->rx_amsdu_freeq, AGGR_NUM_OF_FREE_NETBUFS);

    return p_aggr;
}

void aggr_recv_delba_req_evt(struct ath6kl_vif *vif, u8 tid_mux)
{
    struct ath6kl_sta *sta;
    struct rxtid *rxtid;
    struct aggr_info_conn *aggr_conn = NULL;
    u8 tid, aid;

    if (vif->nw_type == AP_NETWORK) {
        aid = ath6kl_get_aid(tid_mux);
        sta = ath6kl_find_sta_by_aid(vif->ar, aid);
        if (sta)
            aggr_conn = sta->aggr_conn;
    } else
        aggr_conn = vif->aggr_cntxt->aggr_conn;

    if (!aggr_conn)
        return;

    tid = ath6kl_get_tid(tid_mux);
    if (tid >= NUM_OF_TIDS)
        return;

    rxtid = &aggr_conn->rx_tid[tid];

    if (rxtid->aggr)
        aggr_delete_tid_state(aggr_conn, tid);
}

void aggr_reset_state(struct aggr_info_conn *aggr_conn)
{
    u8 tid;

    if (!aggr_conn)
        return;

    if (aggr_conn->timer_scheduled) {
        del_timer(&aggr_conn->timer);
        aggr_conn->timer_scheduled = false;
    }

    for (tid = 0; tid < NUM_OF_TIDS; tid++)
        aggr_delete_tid_state(aggr_conn, tid);
}

/* clean up our amsdu buffer list */
void ath6kl_cleanup_amsdu_rxbufs(struct ath6kl *ar)
{
    struct htc_packet *packet, *tmp_pkt;

    spin_lock_bh(&ar->lock);
    if (list_empty(&ar->amsdu_rx_buffer_queue)) {
        spin_unlock_bh(&ar->lock);
        return;
    }

    list_for_each_entry_safe(packet, tmp_pkt, &ar->amsdu_rx_buffer_queue,
                 list) {
        list_del(&packet->list);
        spin_unlock_bh(&ar->lock);
        dev_kfree_skb(packet->pkt_cntxt);
        spin_lock_bh(&ar->lock);
    }

    spin_unlock_bh(&ar->lock);
}

void aggr_module_destroy(struct aggr_info *aggr_info)
{
    if (!aggr_info)
        return;

    aggr_reset_state(aggr_info->aggr_conn);
    skb_queue_purge(&aggr_info->rx_amsdu_freeq);
    kfree(aggr_info->aggr_conn);
    kfree(aggr_info);
}