tx.c

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/*
 * This file is part of wl1271
 *
 * Copyright (C) 2009 Nokia Corporation
 *
 * Contact: Luciano Coelho <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * 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; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/etherdevice.h>

#include "wlcore.h"
#include "debug.h"
#include "io.h"
#include "ps.h"
#include "tx.h"
#include "event.h"
#include "hw_ops.h"

/*
 * TODO: this is here just for now, it must be removed when the data
 * operations are in place.
 */
#include "../wl12xx/reg.h"

static int wl1271_set_default_wep_key(struct wl1271 *wl,
                      struct wl12xx_vif *wlvif, u8 id)
{
    int ret;
    bool is_ap = (wlvif->bss_type == BSS_TYPE_AP_BSS);

    if (is_ap)
        ret = wl12xx_cmd_set_default_wep_key(wl, id,
                             wlvif->ap.bcast_hlid);
    else
        ret = wl12xx_cmd_set_default_wep_key(wl, id, wlvif->sta.hlid);

    if (ret < 0)
        return ret;

    wl1271_debug(DEBUG_CRYPT, "default wep key idx: %d", (int)id);
    return 0;
}

static int wl1271_alloc_tx_id(struct wl1271 *wl, struct sk_buff *skb)
{
    int id;

    id = find_first_zero_bit(wl->tx_frames_map, wl->num_tx_desc);
    if (id >= wl->num_tx_desc)
        return -EBUSY;

    __set_bit(id, wl->tx_frames_map);
    wl->tx_frames[id] = skb;
    wl->tx_frames_cnt++;
    return id;
}

void wl1271_free_tx_id(struct wl1271 *wl, int id)
{
    if (__test_and_clear_bit(id, wl->tx_frames_map)) {
        if (unlikely(wl->tx_frames_cnt == wl->num_tx_desc))
            clear_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags);

        wl->tx_frames[id] = NULL;
        wl->tx_frames_cnt--;
    }
}
EXPORT_SYMBOL(wl1271_free_tx_id);

static void wl1271_tx_ap_update_inconnection_sta(struct wl1271 *wl,
                         struct sk_buff *skb)
{
    struct ieee80211_hdr *hdr;

    /*
     * add the station to the known list before transmitting the
     * authentication response. this way it won't get de-authed by FW
     * when transmitting too soon.
     */
    hdr = (struct ieee80211_hdr *)(skb->data +
                       sizeof(struct wl1271_tx_hw_descr));
    if (ieee80211_is_auth(hdr->frame_control))
        wl1271_acx_set_inconnection_sta(wl, hdr->addr1);
}

static void wl1271_tx_regulate_link(struct wl1271 *wl,
                    struct wl12xx_vif *wlvif,
                    u8 hlid)
{
    bool fw_ps, single_sta;
    u8 tx_pkts;

    if (WARN_ON(!test_bit(hlid, wlvif->links_map)))
        return;

    fw_ps = test_bit(hlid, (unsigned long *)&wl->ap_fw_ps_map);
    tx_pkts = wl->links[hlid].allocated_pkts;
    single_sta = (wl->active_sta_count == 1);

    /*
     * if in FW PS and there is enough data in FW we can put the link
     * into high-level PS and clean out its TX queues.
     * Make an exception if this is the only connected station. In this
     * case FW-memory congestion is not a problem.
     */
    if (!single_sta && fw_ps && tx_pkts >= WL1271_PS_STA_MAX_PACKETS)
        wl12xx_ps_link_start(wl, wlvif, hlid, true);
}

bool wl12xx_is_dummy_packet(struct wl1271 *wl, struct sk_buff *skb)
{
    return wl->dummy_packet == skb;
}
EXPORT_SYMBOL(wl12xx_is_dummy_packet);

static u8 wl12xx_tx_get_hlid_ap(struct wl1271 *wl, struct wl12xx_vif *wlvif,
                struct sk_buff *skb, struct ieee80211_sta *sta)
{
    if (sta) {
        struct wl1271_station *wl_sta;

        wl_sta = (struct wl1271_station *)sta->drv_priv;
        return wl_sta->hlid;
    } else {
        struct ieee80211_hdr *hdr;

        if (!test_bit(WLVIF_FLAG_AP_STARTED, &wlvif->flags))
            return wl->system_hlid;

        hdr = (struct ieee80211_hdr *)skb->data;
        if (is_multicast_ether_addr(ieee80211_get_DA(hdr)))
            return wlvif->ap.bcast_hlid;
        else
            return wlvif->ap.global_hlid;
    }
}

u8 wl12xx_tx_get_hlid(struct wl1271 *wl, struct wl12xx_vif *wlvif,
              struct sk_buff *skb, struct ieee80211_sta *sta)
{
    struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;

    if (!wlvif || wl12xx_is_dummy_packet(wl, skb))
        return wl->system_hlid;

    if (wlvif->bss_type == BSS_TYPE_AP_BSS)
        return wl12xx_tx_get_hlid_ap(wl, wlvif, skb, sta);

    if ((test_bit(WLVIF_FLAG_STA_ASSOCIATED, &wlvif->flags) ||
         test_bit(WLVIF_FLAG_IBSS_JOINED, &wlvif->flags)) &&
        !ieee80211_is_auth(hdr->frame_control) &&
        !ieee80211_is_assoc_req(hdr->frame_control))
        return wlvif->sta.hlid;
    else
        return wlvif->dev_hlid;
}

unsigned int wlcore_calc_packet_alignment(struct wl1271 *wl,
                      unsigned int packet_length)
{
    if ((wl->quirks & WLCORE_QUIRK_TX_PAD_LAST_FRAME) ||
        !(wl->quirks & WLCORE_QUIRK_TX_BLOCKSIZE_ALIGN))
        return ALIGN(packet_length, WL1271_TX_ALIGN_TO);
    else
        return ALIGN(packet_length, WL12XX_BUS_BLOCK_SIZE);
}
EXPORT_SYMBOL(wlcore_calc_packet_alignment);

static int wl1271_tx_allocate(struct wl1271 *wl, struct wl12xx_vif *wlvif,
                  struct sk_buff *skb, u32 extra, u32 buf_offset,
                  u8 hlid, bool is_gem)
{
    struct wl1271_tx_hw_descr *desc;
    u32 total_len = skb->len + sizeof(struct wl1271_tx_hw_descr) + extra;
    u32 total_blocks;
    int id, ret = -EBUSY, ac;
    u32 spare_blocks;

    if (buf_offset + total_len > wl->aggr_buf_size)
        return -EAGAIN;

    spare_blocks = wlcore_hw_get_spare_blocks(wl, is_gem);

    /* allocate free identifier for the packet */
    id = wl1271_alloc_tx_id(wl, skb);
    if (id < 0)
        return id;

    total_blocks = wlcore_hw_calc_tx_blocks(wl, total_len, spare_blocks);

    if (total_blocks <= wl->tx_blocks_available) {
        desc = (struct wl1271_tx_hw_descr *)skb_push(
            skb, total_len - skb->len);

        wlcore_hw_set_tx_desc_blocks(wl, desc, total_blocks,
                         spare_blocks);

        desc->id = id;

        wl->tx_blocks_available -= total_blocks;
        wl->tx_allocated_blocks += total_blocks;

        /* If the FW was empty before, arm the Tx watchdog */
        if (wl->tx_allocated_blocks == total_blocks)
            wl12xx_rearm_tx_watchdog_locked(wl);

        ac = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
        wl->tx_allocated_pkts[ac]++;

        if (!wl12xx_is_dummy_packet(wl, skb) && wlvif &&
            wlvif->bss_type == BSS_TYPE_AP_BSS &&
            test_bit(hlid, wlvif->ap.sta_hlid_map))
            wl->links[hlid].allocated_pkts++;

        ret = 0;

        wl1271_debug(DEBUG_TX,
                 "tx_allocate: size: %d, blocks: %d, id: %d",
                 total_len, total_blocks, id);
    } else {
        wl1271_free_tx_id(wl, id);
    }

    return ret;
}

static void wl1271_tx_fill_hdr(struct wl1271 *wl, struct wl12xx_vif *wlvif,
                   struct sk_buff *skb, u32 extra,
                   struct ieee80211_tx_info *control, u8 hlid)
{
    struct timespec ts;
    struct wl1271_tx_hw_descr *desc;
    int ac, rate_idx;
    s64 hosttime;
    u16 tx_attr = 0;
    __le16 frame_control;
    struct ieee80211_hdr *hdr;
    u8 *frame_start;
    bool is_dummy;

    desc = (struct wl1271_tx_hw_descr *) skb->data;
    frame_start = (u8 *)(desc + 1);
    hdr = (struct ieee80211_hdr *)(frame_start + extra);
    frame_control = hdr->frame_control;

    /* relocate space for security header */
    if (extra) {
        int hdrlen = ieee80211_hdrlen(frame_control);
        memmove(frame_start, hdr, hdrlen);
        skb_set_network_header(skb, skb_network_offset(skb) + extra);
    }

    /* configure packet life time */
    getnstimeofday(&ts);
    hosttime = (timespec_to_ns(&ts) >> 10);
    desc->start_time = cpu_to_le32(hosttime - wl->time_offset);

    is_dummy = wl12xx_is_dummy_packet(wl, skb);
    if (is_dummy || !wlvif || wlvif->bss_type != BSS_TYPE_AP_BSS)
        desc->life_time = cpu_to_le16(TX_HW_MGMT_PKT_LIFETIME_TU);
    else
        desc->life_time = cpu_to_le16(TX_HW_AP_MODE_PKT_LIFETIME_TU);

    /* queue */
    ac = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
    desc->tid = skb->priority;

    if (is_dummy) {
        /*
         * FW expects the dummy packet to have an invalid session id -
         * any session id that is different than the one set in the join
         */
        tx_attr = (SESSION_COUNTER_INVALID <<
               TX_HW_ATTR_OFST_SESSION_COUNTER) &
               TX_HW_ATTR_SESSION_COUNTER;

        tx_attr |= TX_HW_ATTR_TX_DUMMY_REQ;
    } else if (wlvif) {
        /* configure the tx attributes */
        tx_attr = wlvif->session_counter <<
              TX_HW_ATTR_OFST_SESSION_COUNTER;
    }

    desc->hlid = hlid;
    if (is_dummy || !wlvif)
        rate_idx = 0;
    else if (wlvif->bss_type != BSS_TYPE_AP_BSS) {
        /*
         * if the packets are data packets
         * send them with AP rate policies (EAPOLs are an exception),
         * otherwise use default basic rates
         */
        if (skb->protocol == cpu_to_be16(ETH_P_PAE))
            rate_idx = wlvif->sta.basic_rate_idx;
        else if (control->flags & IEEE80211_TX_CTL_NO_CCK_RATE)
            rate_idx = wlvif->sta.p2p_rate_idx;
        else if (ieee80211_is_data(frame_control))
            rate_idx = wlvif->sta.ap_rate_idx;
        else
            rate_idx = wlvif->sta.basic_rate_idx;
    } else {
        if (hlid == wlvif->ap.global_hlid)
            rate_idx = wlvif->ap.mgmt_rate_idx;
        else if (hlid == wlvif->ap.bcast_hlid ||
             skb->protocol == cpu_to_be16(ETH_P_PAE) ||
             !ieee80211_is_data(frame_control))
            /*
             * send non-data, bcast and EAPOLs using the
             * min basic rate
             */
            rate_idx = wlvif->ap.bcast_rate_idx;
        else
            rate_idx = wlvif->ap.ucast_rate_idx[ac];
    }

    tx_attr |= rate_idx << TX_HW_ATTR_OFST_RATE_POLICY;

    /* for WEP shared auth - no fw encryption is needed */
    if (ieee80211_is_auth(frame_control) &&
        ieee80211_has_protected(frame_control))
        tx_attr |= TX_HW_ATTR_HOST_ENCRYPT;

    desc->tx_attr = cpu_to_le16(tx_attr);

    wlcore_hw_set_tx_desc_csum(wl, desc, skb);
    wlcore_hw_set_tx_desc_data_len(wl, desc, skb);
}

/* caller must hold wl->mutex */
static int wl1271_prepare_tx_frame(struct wl1271 *wl, struct wl12xx_vif *wlvif,
                   struct sk_buff *skb, u32 buf_offset, u8 hlid)
{
    struct ieee80211_tx_info *info;
    u32 extra = 0;
    int ret = 0;
    u32 total_len;
    bool is_dummy;
    bool is_gem = false;

    if (!skb) {
        wl1271_error("discarding null skb");
        return -EINVAL;
    }

    if (hlid == WL12XX_INVALID_LINK_ID) {
        wl1271_error("invalid hlid. dropping skb 0x%p", skb);
        return -EINVAL;
    }

    info = IEEE80211_SKB_CB(skb);

    is_dummy = wl12xx_is_dummy_packet(wl, skb);

    if ((wl->quirks & WLCORE_QUIRK_TKIP_HEADER_SPACE) &&
        info->control.hw_key &&
        info->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP)
        extra = WL1271_EXTRA_SPACE_TKIP;

    if (info->control.hw_key) {
        bool is_wep;
        u8 idx = info->control.hw_key->hw_key_idx;
        u32 cipher = info->control.hw_key->cipher;

        is_wep = (cipher == WLAN_CIPHER_SUITE_WEP40) ||
             (cipher == WLAN_CIPHER_SUITE_WEP104);

        if (unlikely(is_wep && wlvif->default_key != idx)) {
            ret = wl1271_set_default_wep_key(wl, wlvif, idx);
            if (ret < 0)
                return ret;
            wlvif->default_key = idx;
        }

        is_gem = (cipher == WL1271_CIPHER_SUITE_GEM);
    }

    ret = wl1271_tx_allocate(wl, wlvif, skb, extra, buf_offset, hlid,
                 is_gem);
    if (ret < 0)
        return ret;

    wl1271_tx_fill_hdr(wl, wlvif, skb, extra, info, hlid);

    if (!is_dummy && wlvif && wlvif->bss_type == BSS_TYPE_AP_BSS) {
        wl1271_tx_ap_update_inconnection_sta(wl, skb);
        wl1271_tx_regulate_link(wl, wlvif, hlid);
    }

    /*
     * The length of each packet is stored in terms of
     * words. Thus, we must pad the skb data to make sure its
     * length is aligned.  The number of padding bytes is computed
     * and set in wl1271_tx_fill_hdr.
     * In special cases, we want to align to a specific block size
     * (eg. for wl128x with SDIO we align to 256).
     */
    total_len = wlcore_calc_packet_alignment(wl, skb->len);

    memcpy(wl->aggr_buf + buf_offset, skb->data, skb->len);
    memset(wl->aggr_buf + buf_offset + skb->len, 0, total_len - skb->len);

    /* Revert side effects in the dummy packet skb, so it can be reused */
    if (is_dummy)
        skb_pull(skb, sizeof(struct wl1271_tx_hw_descr));

    return total_len;
}

u32 wl1271_tx_enabled_rates_get(struct wl1271 *wl, u32 rate_set,
                enum ieee80211_band rate_band)
{
    struct ieee80211_supported_band *band;
    u32 enabled_rates = 0;
    int bit;

    band = wl->hw->wiphy->bands[rate_band];
    for (bit = 0; bit < band->n_bitrates; bit++) {
        if (rate_set & 0x1)
            enabled_rates |= band->bitrates[bit].hw_value;
        rate_set >>= 1;
    }

    /* MCS rates indication are on bits 16 - 31 */
    rate_set >>= HW_HT_RATES_OFFSET - band->n_bitrates;

    for (bit = 0; bit < 16; bit++) {
        if (rate_set & 0x1)
            enabled_rates |= (CONF_HW_BIT_RATE_MCS_0 << bit);
        rate_set >>= 1;
    }

    return enabled_rates;
}

void wl1271_handle_tx_low_watermark(struct wl1271 *wl)
{
    int i;

    for (i = 0; i < NUM_TX_QUEUES; i++) {
        if (wlcore_is_queue_stopped_by_reason(wl, i,
            WLCORE_QUEUE_STOP_REASON_WATERMARK) &&
            wl->tx_queue_count[i] <= WL1271_TX_QUEUE_LOW_WATERMARK) {
            /* firmware buffer has space, restart queues */
            wlcore_wake_queue(wl, i,
                      WLCORE_QUEUE_STOP_REASON_WATERMARK);
        }
    }
}

static struct sk_buff_head *wl1271_select_queue(struct wl1271 *wl,
                        struct sk_buff_head *queues)
{
    int i, q = -1, ac;
    u32 min_pkts = 0xffffffff;

    /*
     * Find a non-empty ac where:
     * 1. There are packets to transmit
     * 2. The FW has the least allocated blocks
     *
     * We prioritize the ACs according to VO>VI>BE>BK
     */
    for (i = 0; i < NUM_TX_QUEUES; i++) {
        ac = wl1271_tx_get_queue(i);
        if (!skb_queue_empty(&queues[ac]) &&
            (wl->tx_allocated_pkts[ac] < min_pkts)) {
            q = ac;
            min_pkts = wl->tx_allocated_pkts[q];
        }
    }

    if (q == -1)
        return NULL;

    return &queues[q];
}

static struct sk_buff *wl12xx_lnk_skb_dequeue(struct wl1271 *wl,
                          struct wl1271_link *lnk)
{
    struct sk_buff *skb;
    unsigned long flags;
    struct sk_buff_head *queue;

    queue = wl1271_select_queue(wl, lnk->tx_queue);
    if (!queue)
        return NULL;

    skb = skb_dequeue(queue);
    if (skb) {
        int q = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
        spin_lock_irqsave(&wl->wl_lock, flags);
        WARN_ON_ONCE(wl->tx_queue_count[q] <= 0);
        wl->tx_queue_count[q]--;
        spin_unlock_irqrestore(&wl->wl_lock, flags);
    }

    return skb;
}

static struct sk_buff *wl12xx_vif_skb_dequeue(struct wl1271 *wl,
                          struct wl12xx_vif *wlvif,
                          u8 *hlid)
{
    struct sk_buff *skb = NULL;
    int i, h, start_hlid;

    /* start from the link after the last one */
    start_hlid = (wlvif->last_tx_hlid + 1) % WL12XX_MAX_LINKS;

    /* dequeue according to AC, round robin on each link */
    for (i = 0; i < WL12XX_MAX_LINKS; i++) {
        h = (start_hlid + i) % WL12XX_MAX_LINKS;

        /* only consider connected stations */
        if (!test_bit(h, wlvif->links_map))
            continue;

        skb = wl12xx_lnk_skb_dequeue(wl, &wl->links[h]);
        if (!skb)
            continue;

        wlvif->last_tx_hlid = h;
        break;
    }

    if (!skb)
        wlvif->last_tx_hlid = 0;

    *hlid = wlvif->last_tx_hlid;
    return skb;
}

static struct sk_buff *wl1271_skb_dequeue(struct wl1271 *wl, u8 *hlid)
{
    unsigned long flags;
    struct wl12xx_vif *wlvif = wl->last_wlvif;
    struct sk_buff *skb = NULL;

    /* continue from last wlvif (round robin) */
    if (wlvif) {
        wl12xx_for_each_wlvif_continue(wl, wlvif) {
            skb = wl12xx_vif_skb_dequeue(wl, wlvif, hlid);
            if (skb) {
                wl->last_wlvif = wlvif;
                break;
            }
        }
    }

    /* dequeue from the system HLID before the restarting wlvif list */
    if (!skb) {
        skb = wl12xx_lnk_skb_dequeue(wl, &wl->links[wl->system_hlid]);
        *hlid = wl->system_hlid;
    }

    /* do a new pass over the wlvif list */
    if (!skb) {
        wl12xx_for_each_wlvif(wl, wlvif) {
            skb = wl12xx_vif_skb_dequeue(wl, wlvif, hlid);
            if (skb) {
                wl->last_wlvif = wlvif;
                break;
            }

            /*
             * No need to continue after last_wlvif. The previous
             * pass should have found it.
             */
            if (wlvif == wl->last_wlvif)
                break;
        }
    }

    if (!skb &&
        test_and_clear_bit(WL1271_FLAG_DUMMY_PACKET_PENDING, &wl->flags)) {
        int q;

        skb = wl->dummy_packet;
        *hlid = wl->system_hlid;
        q = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
        spin_lock_irqsave(&wl->wl_lock, flags);
        WARN_ON_ONCE(wl->tx_queue_count[q] <= 0);
        wl->tx_queue_count[q]--;
        spin_unlock_irqrestore(&wl->wl_lock, flags);
    }

    return skb;
}

static void wl1271_skb_queue_head(struct wl1271 *wl, struct wl12xx_vif *wlvif,
                  struct sk_buff *skb, u8 hlid)
{
    unsigned long flags;
    int q = wl1271_tx_get_queue(skb_get_queue_mapping(skb));

    if (wl12xx_is_dummy_packet(wl, skb)) {
        set_bit(WL1271_FLAG_DUMMY_PACKET_PENDING, &wl->flags);
    } else {
        skb_queue_head(&wl->links[hlid].tx_queue[q], skb);

        /* make sure we dequeue the same packet next time */
        wlvif->last_tx_hlid = (hlid + WL12XX_MAX_LINKS - 1) %
                      WL12XX_MAX_LINKS;
    }

    spin_lock_irqsave(&wl->wl_lock, flags);
    wl->tx_queue_count[q]++;
    spin_unlock_irqrestore(&wl->wl_lock, flags);
}

static bool wl1271_tx_is_data_present(struct sk_buff *skb)
{
    struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)(skb->data);

    return ieee80211_is_data_present(hdr->frame_control);
}

void wl12xx_rearm_rx_streaming(struct wl1271 *wl, unsigned long *active_hlids)
{
    struct wl12xx_vif *wlvif;
    u32 timeout;
    u8 hlid;

    if (!wl->conf.rx_streaming.interval)
        return;

    if (!wl->conf.rx_streaming.always &&
        !test_bit(WL1271_FLAG_SOFT_GEMINI, &wl->flags))
        return;

    timeout = wl->conf.rx_streaming.duration;
    wl12xx_for_each_wlvif_sta(wl, wlvif) {
        bool found = false;
        for_each_set_bit(hlid, active_hlids, WL12XX_MAX_LINKS) {
            if (test_bit(hlid, wlvif->links_map)) {
                found  = true;
                break;
            }
        }

        if (!found)
            continue;

        /* enable rx streaming */
        if (!test_bit(WLVIF_FLAG_RX_STREAMING_STARTED, &wlvif->flags))
            ieee80211_queue_work(wl->hw,
                         &wlvif->rx_streaming_enable_work);

        mod_timer(&wlvif->rx_streaming_timer,
              jiffies + msecs_to_jiffies(timeout));
    }
}

/*
 * Returns failure values only in case of failed bus ops within this function.
 * wl1271_prepare_tx_frame retvals won't be returned in order to avoid
 * triggering recovery by higher layers when not necessary.
 * In case a FW command fails within wl1271_prepare_tx_frame fails a recovery
 * will be queued in wl1271_cmd_send. -EAGAIN/-EBUSY from prepare_tx_frame
 * can occur and are legitimate so don't propagate. -EINVAL will emit a WARNING
 * within prepare_tx_frame code but there's nothing we should do about those
 * as well.
 */
int wlcore_tx_work_locked(struct wl1271 *wl)
{
    struct wl12xx_vif *wlvif;
    struct sk_buff *skb;
    struct wl1271_tx_hw_descr *desc;
    u32 buf_offset = 0, last_len = 0;
    bool sent_packets = false;
    unsigned long active_hlids[BITS_TO_LONGS(WL12XX_MAX_LINKS)] = {0};
    int ret = 0;
    int bus_ret = 0;
    u8 hlid;

    if (unlikely(wl->state != WLCORE_STATE_ON))
        return 0;

    while ((skb = wl1271_skb_dequeue(wl, &hlid))) {
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        bool has_data = false;

        wlvif = NULL;
        if (!wl12xx_is_dummy_packet(wl, skb) && info->control.vif)
            wlvif = wl12xx_vif_to_data(info->control.vif);
        else
            hlid = wl->system_hlid;

        has_data = wlvif && wl1271_tx_is_data_present(skb);
        ret = wl1271_prepare_tx_frame(wl, wlvif, skb, buf_offset,
                          hlid);
        if (ret == -EAGAIN) {
            /*
             * Aggregation buffer is full.
             * Flush buffer and try again.
             */
            wl1271_skb_queue_head(wl, wlvif, skb, hlid);

            buf_offset = wlcore_hw_pre_pkt_send(wl, buf_offset,
                                last_len);
            bus_ret = wlcore_write_data(wl, REG_SLV_MEM_DATA,
                         wl->aggr_buf, buf_offset, true);
            if (bus_ret < 0)
                goto out;

            sent_packets = true;
            buf_offset = 0;
            continue;
        } else if (ret == -EBUSY) {
            /*
             * Firmware buffer is full.
             * Queue back last skb, and stop aggregating.
             */
            wl1271_skb_queue_head(wl, wlvif, skb, hlid);
            /* No work left, avoid scheduling redundant tx work */
            set_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags);
            goto out_ack;
        } else if (ret < 0) {
            if (wl12xx_is_dummy_packet(wl, skb))
                /*
                 * fw still expects dummy packet,
                 * so re-enqueue it
                 */
                wl1271_skb_queue_head(wl, wlvif, skb, hlid);
            else
                ieee80211_free_txskb(wl->hw, skb);
            goto out_ack;
        }
        last_len = ret;
        buf_offset += last_len;
        wl->tx_packets_count++;
        if (has_data) {
            desc = (struct wl1271_tx_hw_descr *) skb->data;
            __set_bit(desc->hlid, active_hlids);
        }
    }

out_ack:
    if (buf_offset) {
        buf_offset = wlcore_hw_pre_pkt_send(wl, buf_offset, last_len);
        bus_ret = wlcore_write_data(wl, REG_SLV_MEM_DATA, wl->aggr_buf,
                         buf_offset, true);
        if (bus_ret < 0)
            goto out;

        sent_packets = true;
    }
    if (sent_packets) {
        /*
         * Interrupt the firmware with the new packets. This is only
         * required for older hardware revisions
         */
        if (wl->quirks & WLCORE_QUIRK_END_OF_TRANSACTION) {
            bus_ret = wlcore_write32(wl, WL12XX_HOST_WR_ACCESS,
                         wl->tx_packets_count);
            if (bus_ret < 0)
                goto out;
        }

        wl1271_handle_tx_low_watermark(wl);
    }
    wl12xx_rearm_rx_streaming(wl, active_hlids);

out:
    return bus_ret;
}

void wl1271_tx_work(struct work_struct *work)
{
    struct wl1271 *wl = container_of(work, struct wl1271, tx_work);
    int ret;

    mutex_lock(&wl->mutex);
    ret = wl1271_ps_elp_wakeup(wl);
    if (ret < 0)
        goto out;

    ret = wlcore_tx_work_locked(wl);
    if (ret < 0) {
        wl12xx_queue_recovery_work(wl);
        goto out;
    }

    wl1271_ps_elp_sleep(wl);
out:
    mutex_unlock(&wl->mutex);
}

static u8 wl1271_tx_get_rate_flags(u8 rate_class_index)
{
    u8 flags = 0;

    /*
     * TODO: use wl12xx constants when this code is moved to wl12xx, as
     * only it uses Tx-completion.
     */
    if (rate_class_index <= 8)
        flags |= IEEE80211_TX_RC_MCS;

    /*
     * TODO: use wl12xx constants when this code is moved to wl12xx, as
     * only it uses Tx-completion.
     */
    if (rate_class_index == 0)
        flags |= IEEE80211_TX_RC_SHORT_GI;

    return flags;
}

static void wl1271_tx_complete_packet(struct wl1271 *wl,
                      struct wl1271_tx_hw_res_descr *result)
{
    struct ieee80211_tx_info *info;
    struct ieee80211_vif *vif;
    struct wl12xx_vif *wlvif;
    struct sk_buff *skb;
    int id = result->id;
    int rate = -1;
    u8 rate_flags = 0;
    u8 retries = 0;

    /* check for id legality */
    if (unlikely(id >= wl->num_tx_desc || wl->tx_frames[id] == NULL)) {
        wl1271_warning("TX result illegal id: %d", id);
        return;
    }

    skb = wl->tx_frames[id];
    info = IEEE80211_SKB_CB(skb);

    if (wl12xx_is_dummy_packet(wl, skb)) {
        wl1271_free_tx_id(wl, id);
        return;
    }

    /* info->control is valid as long as we don't update info->status */
    vif = info->control.vif;
    wlvif = wl12xx_vif_to_data(vif);

    /* update the TX status info */
    if (result->status == TX_SUCCESS) {
        if (!(info->flags & IEEE80211_TX_CTL_NO_ACK))
            info->flags |= IEEE80211_TX_STAT_ACK;
        rate = wlcore_rate_to_idx(wl, result->rate_class_index,
                      wlvif->band);
        rate_flags = wl1271_tx_get_rate_flags(result->rate_class_index);
        retries = result->ack_failures;
    } else if (result->status == TX_RETRY_EXCEEDED) {
        wl->stats.excessive_retries++;
        retries = result->ack_failures;
    }

    info->status.rates[0].idx = rate;
    info->status.rates[0].count = retries;
    info->status.rates[0].flags = rate_flags;
    info->status.ack_signal = -1;

    wl->stats.retry_count += result->ack_failures;

    /*
     * update sequence number only when relevant, i.e. only in
     * sessions of TKIP, AES and GEM (not in open or WEP sessions)
     */
    if (info->control.hw_key &&
        (info->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP ||
         info->control.hw_key->cipher == WLAN_CIPHER_SUITE_CCMP ||
         info->control.hw_key->cipher == WL1271_CIPHER_SUITE_GEM)) {
        u8 fw_lsb = result->tx_security_sequence_number_lsb;
        u8 cur_lsb = wlvif->tx_security_last_seq_lsb;

        /*
         * update security sequence number, taking care of potential
         * wrap-around
         */
        wlvif->tx_security_seq += (fw_lsb - cur_lsb) & 0xff;
        wlvif->tx_security_last_seq_lsb = fw_lsb;
    }

    /* remove private header from packet */
    skb_pull(skb, sizeof(struct wl1271_tx_hw_descr));

    /* remove TKIP header space if present */
    if ((wl->quirks & WLCORE_QUIRK_TKIP_HEADER_SPACE) &&
        info->control.hw_key &&
        info->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP) {
        int hdrlen = ieee80211_get_hdrlen_from_skb(skb);
        memmove(skb->data + WL1271_EXTRA_SPACE_TKIP, skb->data,
            hdrlen);
        skb_pull(skb, WL1271_EXTRA_SPACE_TKIP);
    }

    wl1271_debug(DEBUG_TX, "tx status id %u skb 0x%p failures %u rate 0x%x"
             " status 0x%x",
             result->id, skb, result->ack_failures,
             result->rate_class_index, result->status);

    /* return the packet to the stack */
    skb_queue_tail(&wl->deferred_tx_queue, skb);
    queue_work(wl->freezable_wq, &wl->netstack_work);
    wl1271_free_tx_id(wl, result->id);
}

/* Called upon reception of a TX complete interrupt */
int wlcore_tx_complete(struct wl1271 *wl)
{
    struct wl1271_acx_mem_map *memmap = wl->target_mem_map;
    u32 count, fw_counter;
    u32 i;
    int ret;

    /* read the tx results from the chipset */
    ret = wlcore_read(wl, le32_to_cpu(memmap->tx_result),
              wl->tx_res_if, sizeof(*wl->tx_res_if), false);
    if (ret < 0)
        goto out;

    fw_counter = le32_to_cpu(wl->tx_res_if->tx_result_fw_counter);

    /* write host counter to chipset (to ack) */
    ret = wlcore_write32(wl, le32_to_cpu(memmap->tx_result) +
                 offsetof(struct wl1271_tx_hw_res_if,
                      tx_result_host_counter), fw_counter);
    if (ret < 0)
        goto out;

    count = fw_counter - wl->tx_results_count;
    wl1271_debug(DEBUG_TX, "tx_complete received, packets: %d", count);

    /* verify that the result buffer is not getting overrun */
    if (unlikely(count > TX_HW_RESULT_QUEUE_LEN))
        wl1271_warning("TX result overflow from chipset: %d", count);

    /* process the results */
    for (i = 0; i < count; i++) {
        struct wl1271_tx_hw_res_descr *result;
        u8 offset = wl->tx_results_count & TX_HW_RESULT_QUEUE_LEN_MASK;

        /* process the packet */
        result =  &(wl->tx_res_if->tx_results_queue[offset]);
        wl1271_tx_complete_packet(wl, result);

        wl->tx_results_count++;
    }

out:
    return ret;
}
EXPORT_SYMBOL(wlcore_tx_complete);

void wl1271_tx_reset_link_queues(struct wl1271 *wl, u8 hlid)
{
    struct sk_buff *skb;
    int i;
    unsigned long flags;
    struct ieee80211_tx_info *info;
    int total[NUM_TX_QUEUES];

    for (i = 0; i < NUM_TX_QUEUES; i++) {
        total[i] = 0;
        while ((skb = skb_dequeue(&wl->links[hlid].tx_queue[i]))) {
            wl1271_debug(DEBUG_TX, "link freeing skb 0x%p", skb);

            if (!wl12xx_is_dummy_packet(wl, skb)) {
                info = IEEE80211_SKB_CB(skb);
                info->status.rates[0].idx = -1;
                info->status.rates[0].count = 0;
                ieee80211_tx_status_ni(wl->hw, skb);
            }

            total[i]++;
        }
    }

    spin_lock_irqsave(&wl->wl_lock, flags);
    for (i = 0; i < NUM_TX_QUEUES; i++)
        wl->tx_queue_count[i] -= total[i];
    spin_unlock_irqrestore(&wl->wl_lock, flags);

    wl1271_handle_tx_low_watermark(wl);
}

/* caller must hold wl->mutex and TX must be stopped */
void wl12xx_tx_reset_wlvif(struct wl1271 *wl, struct wl12xx_vif *wlvif)
{
    int i;

    /* TX failure */
    for_each_set_bit(i, wlvif->links_map, WL12XX_MAX_LINKS) {
        if (wlvif->bss_type == BSS_TYPE_AP_BSS)
            wl1271_free_sta(wl, wlvif, i);
        else
            wlvif->sta.ba_rx_bitmap = 0;

        wl->links[i].allocated_pkts = 0;
        wl->links[i].prev_freed_pkts = 0;
    }
    wlvif->last_tx_hlid = 0;

}
/* caller must hold wl->mutex and TX must be stopped */
void wl12xx_tx_reset(struct wl1271 *wl)
{
    int i;
    struct sk_buff *skb;
    struct ieee80211_tx_info *info;

    /* only reset the queues if something bad happened */
    if (WARN_ON_ONCE(wl1271_tx_total_queue_count(wl) != 0)) {
        for (i = 0; i < WL12XX_MAX_LINKS; i++)
            wl1271_tx_reset_link_queues(wl, i);

        for (i = 0; i < NUM_TX_QUEUES; i++)
            wl->tx_queue_count[i] = 0;
    }

    /*
     * Make sure the driver is at a consistent state, in case this
     * function is called from a context other than interface removal.
     * This call will always wake the TX queues.
     */
    wl1271_handle_tx_low_watermark(wl);

    for (i = 0; i < wl->num_tx_desc; i++) {
        if (wl->tx_frames[i] == NULL)
            continue;

        skb = wl->tx_frames[i];
        wl1271_free_tx_id(wl, i);
        wl1271_debug(DEBUG_TX, "freeing skb 0x%p", skb);

        if (!wl12xx_is_dummy_packet(wl, skb)) {
            /*
             * Remove private headers before passing the skb to
             * mac80211
             */
            info = IEEE80211_SKB_CB(skb);
            skb_pull(skb, sizeof(struct wl1271_tx_hw_descr));
            if ((wl->quirks & WLCORE_QUIRK_TKIP_HEADER_SPACE) &&
                info->control.hw_key &&
                info->control.hw_key->cipher ==
                WLAN_CIPHER_SUITE_TKIP) {
                int hdrlen = ieee80211_get_hdrlen_from_skb(skb);
                memmove(skb->data + WL1271_EXTRA_SPACE_TKIP,
                    skb->data, hdrlen);
                skb_pull(skb, WL1271_EXTRA_SPACE_TKIP);
            }

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

            ieee80211_tx_status_ni(wl->hw, skb);
        }
    }
}

#define WL1271_TX_FLUSH_TIMEOUT 500000

/* caller must *NOT* hold wl->mutex */
void wl1271_tx_flush(struct wl1271 *wl)
{
    unsigned long timeout, start_time;
    int i;
    start_time = jiffies;
    timeout = start_time + usecs_to_jiffies(WL1271_TX_FLUSH_TIMEOUT);

    /* only one flush should be in progress, for consistent queue state */
    mutex_lock(&wl->flush_mutex);

    mutex_lock(&wl->mutex);
    if (wl->tx_frames_cnt == 0 && wl1271_tx_total_queue_count(wl) == 0) {
        mutex_unlock(&wl->mutex);
        goto out;
    }

    wlcore_stop_queues(wl, WLCORE_QUEUE_STOP_REASON_FLUSH);

    while (!time_after(jiffies, timeout)) {
        wl1271_debug(DEBUG_MAC80211, "flushing tx buffer: %d %d",
                 wl->tx_frames_cnt,
                 wl1271_tx_total_queue_count(wl));

        /* force Tx and give the driver some time to flush data */
        mutex_unlock(&wl->mutex);
        if (wl1271_tx_total_queue_count(wl))
            wl1271_tx_work(&wl->tx_work);
        msleep(20);
        mutex_lock(&wl->mutex);

        if ((wl->tx_frames_cnt == 0) &&
            (wl1271_tx_total_queue_count(wl) == 0)) {
            wl1271_debug(DEBUG_MAC80211, "tx flush took %d ms",
                     jiffies_to_msecs(jiffies - start_time));
            goto out_wake;
        }
    }

    wl1271_warning("Unable to flush all TX buffers, "
               "timed out (timeout %d ms",
               WL1271_TX_FLUSH_TIMEOUT / 1000);

    /* forcibly flush all Tx buffers on our queues */
    for (i = 0; i < WL12XX_MAX_LINKS; i++)
        wl1271_tx_reset_link_queues(wl, i);

out_wake:
    wlcore_wake_queues(wl, WLCORE_QUEUE_STOP_REASON_FLUSH);
    mutex_unlock(&wl->mutex);
out:
    mutex_unlock(&wl->flush_mutex);
}
EXPORT_SYMBOL_GPL(wl1271_tx_flush);

u32 wl1271_tx_min_rate_get(struct wl1271 *wl, u32 rate_set)
{
    if (WARN_ON(!rate_set))
        return 0;

    return BIT(__ffs(rate_set));
}

void wlcore_stop_queue_locked(struct wl1271 *wl, u8 queue,
                  enum wlcore_queue_stop_reason reason)
{
    bool stopped = !!wl->queue_stop_reasons[queue];

    /* queue should not be stopped for this reason */
    WARN_ON(test_and_set_bit(reason, &wl->queue_stop_reasons[queue]));

    if (stopped)
        return;

    ieee80211_stop_queue(wl->hw, wl1271_tx_get_mac80211_queue(queue));
}

void wlcore_stop_queue(struct wl1271 *wl, u8 queue,
               enum wlcore_queue_stop_reason reason)
{
    unsigned long flags;

    spin_lock_irqsave(&wl->wl_lock, flags);
    wlcore_stop_queue_locked(wl, queue, reason);
    spin_unlock_irqrestore(&wl->wl_lock, flags);
}

void wlcore_wake_queue(struct wl1271 *wl, u8 queue,
               enum wlcore_queue_stop_reason reason)
{
    unsigned long flags;

    spin_lock_irqsave(&wl->wl_lock, flags);

    /* queue should not be clear for this reason */
    WARN_ON(!test_and_clear_bit(reason, &wl->queue_stop_reasons[queue]));

    if (wl->queue_stop_reasons[queue])
        goto out;

    ieee80211_wake_queue(wl->hw, wl1271_tx_get_mac80211_queue(queue));

out:
    spin_unlock_irqrestore(&wl->wl_lock, flags);
}

void wlcore_stop_queues(struct wl1271 *wl,
            enum wlcore_queue_stop_reason reason)
{
    int i;

    for (i = 0; i < NUM_TX_QUEUES; i++)
        wlcore_stop_queue(wl, i, reason);
}
EXPORT_SYMBOL_GPL(wlcore_stop_queues);

void wlcore_wake_queues(struct wl1271 *wl,
            enum wlcore_queue_stop_reason reason)
{
    int i;

    for (i = 0; i < NUM_TX_QUEUES; i++)
        wlcore_wake_queue(wl, i, reason);
}
EXPORT_SYMBOL_GPL(wlcore_wake_queues);

void wlcore_reset_stopped_queues(struct wl1271 *wl)
{
    int i;
    unsigned long flags;

    spin_lock_irqsave(&wl->wl_lock, flags);

    for (i = 0; i < NUM_TX_QUEUES; i++) {
        if (!wl->queue_stop_reasons[i])
            continue;

        wl->queue_stop_reasons[i] = 0;
        ieee80211_wake_queue(wl->hw,
                     wl1271_tx_get_mac80211_queue(i));
    }

    spin_unlock_irqrestore(&wl->wl_lock, flags);
}

bool wlcore_is_queue_stopped_by_reason(struct wl1271 *wl, u8 queue,
                 enum wlcore_queue_stop_reason reason)
{
    return test_bit(reason, &wl->queue_stop_reasons[queue]);
}

bool wlcore_is_queue_stopped(struct wl1271 *wl, u8 queue)
{
    return !!wl->queue_stop_reasons[queue];
}