wlcore: Propagate errors from wl1271_read

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / net / wireless / ti / wlcore / tx.c

/*
 * This file is part of wl1271
 *
 * Copyright (C) 2009 Nokia Corporation
 *
 * Contact: Luciano Coelho <luciano.coelho@nokia.com>
 *
 * 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);

u8 wl12xx_tx_get_hlid_ap(struct wl1271 *wl, struct wl12xx_vif *wlvif,
                         struct sk_buff *skb)
{
        struct ieee80211_tx_info *control = IEEE80211_SKB_CB(skb);

        if (control->control.sta) {
                struct wl1271_station *wl_sta;

                wl_sta = (struct wl1271_station *)
                                control->control.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_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);

        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 > WL1271_AGGR_BUFFER_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 destined for AP (have a STA entry)
                 * send them with AP rate policies (EAPOLs are an exception),
                 * otherwise use default basic rates
                 */
                if (control->flags & IEEE80211_TX_CTL_NO_CCK_RATE)
                        rate_idx = wlvif->sta.p2p_rate_idx;
                else if (skb->protocol == cpu_to_be16(ETH_P_PAE))
                        rate_idx = wlvif->sta.basic_rate_idx;
                else if (control->control.sta)
                        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)
                        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)
{
        struct ieee80211_tx_info *info;
        u32 extra = 0;
        int ret = 0;
        u32 total_len;
        u8 hlid;
        bool is_dummy;
        bool is_gem = false;

        if (!skb)
                return -EINVAL;

        info = IEEE80211_SKB_CB(skb);

        /* TODO: handle dummy packets on multi-vifs */
        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);
        }
        hlid = wl12xx_tx_get_hlid(wl, wlvif, skb);
        if (hlid == WL12XX_INVALID_LINK_ID) {
                wl1271_error("invalid hlid. dropping skb 0x%p", skb);
                return -EINVAL;
        }

        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)
{
        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;

        return skb;
}

static struct sk_buff *wl1271_skb_dequeue(struct wl1271 *wl)
{
        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);
                        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]);

        /* do a new pass over the wlvif list */
        if (!skb) {
                wl12xx_for_each_wlvif(wl, wlvif) {
                        skb = wl12xx_vif_skb_dequeue(wl, wlvif);
                        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;
                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)
{
        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 {
                u8 hlid = wl12xx_tx_get_hlid(wl, wlvif, skb);
                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));
        }
}

void wl1271_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;

        if (unlikely(wl->state == WL1271_STATE_OFF))
                return;

        while ((skb = wl1271_skb_dequeue(wl))) {
                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);

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

                        buf_offset = wlcore_hw_pre_pkt_send(wl, buf_offset,
                                                            last_len);
                        wlcore_write_data(wl, REG_SLV_MEM_DATA, wl->aggr_buf,
                                          buf_offset, true);
                        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);
                        /* 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);
                        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);
                wlcore_write_data(wl, REG_SLV_MEM_DATA, wl->aggr_buf,
                                  buf_offset, true);
                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)
                        wl1271_write32(wl, WL12XX_HOST_WR_ACCESS,
                                       wl->tx_packets_count);

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

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;

        wl1271_tx_work_locked(wl);

        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 =
                (struct wl1271_acx_mem_map *)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) */
        wl1271_write32(wl, le32_to_cpu(memmap->tx_result) +
                       offsetof(struct wl1271_tx_hw_res_if,
                                tx_result_host_counter), fw_counter);

        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;
        int i;
        timeout = jiffies + usecs_to_jiffies(WL1271_TX_FLUSH_TIMEOUT);

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

        wlcore_stop_queues(wl, WLCORE_QUEUE_STOP_REASON_FLUSH);

        while (!time_after(jiffies, timeout)) {
                mutex_lock(&wl->mutex);
                wl1271_debug(DEBUG_TX, "flushing tx buffer: %d %d",
                             wl->tx_frames_cnt,
                             wl1271_tx_total_queue_count(wl));
                if ((wl->tx_frames_cnt == 0) &&
                    (wl1271_tx_total_queue_count(wl) == 0)) {
                        mutex_unlock(&wl->mutex);
                        goto out;
                }
                mutex_unlock(&wl->mutex);
                msleep(1);
        }

        wl1271_warning("Unable to flush all TX buffers, timed out.");

        /* forcibly flush all Tx buffers on our queues */
        mutex_lock(&wl->mutex);
        for (i = 0; i < WL12XX_MAX_LINKS; i++)
                wl1271_tx_reset_link_queues(wl, i);
        mutex_unlock(&wl->mutex);

out:
        wlcore_wake_queues(wl, WLCORE_QUEUE_STOP_REASON_FLUSH);
        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];
}