p54: Move TX/RX code

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / net / wireless / p54 / txrx.c

/*
 * Common code for mac80211 Prism54 drivers
 *
 * Copyright (c) 2006, Michael Wu <flamingice@sourmilk.net>
 * Copyright (c) 2007-2009, Christian Lamparter <chunkeey@web.de>
 * Copyright 2008, Johannes Berg <johannes@sipsolutions.net>
 *
 * Based on:
 * - the islsm (softmac prism54) driver, which is:
 *   Copyright 2004-2006 Jean-Baptiste Note <jbnote@gmail.com>, et al.
 * - stlc45xx driver
 *   Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
 *
 * 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.
 */

#include <linux/init.h>
#include <linux/firmware.h>
#include <linux/etherdevice.h>

#include <net/mac80211.h>

#include "p54.h"
#include "lmac.h"

#ifdef P54_MM_DEBUG
static void p54_dump_tx_queue(struct p54_common *priv)
{
        unsigned long flags;
        struct ieee80211_tx_info *info;
        struct p54_tx_info *range;
        struct sk_buff *skb;
        struct p54_hdr *hdr;
        unsigned int i = 0;
        u32 prev_addr;
        u32 largest_hole = 0, free;

        spin_lock_irqsave(&priv->tx_queue.lock, flags);
        printk(KERN_DEBUG "%s: / --- tx queue dump (%d entries) --- \n",
               wiphy_name(priv->hw->wiphy), skb_queue_len(&priv->tx_queue));

        prev_addr = priv->rx_start;
        skb_queue_walk(&priv->tx_queue, skb) {
                info = IEEE80211_SKB_CB(skb);
                range = (void *) info->rate_driver_data;
                hdr = (void *) skb->data;

                free = range->start_addr - prev_addr;
                printk(KERN_DEBUG "%s: | [%02d] => [skb:%p skb_len:0x%04x "
                       "hdr:{flags:%02x len:%04x req_id:%04x type:%02x} "
                       "mem:{start:%04x end:%04x, free:%d}]\n",
                       wiphy_name(priv->hw->wiphy), i++, skb, skb->len,
                       le16_to_cpu(hdr->flags), le16_to_cpu(hdr->len),
                       le32_to_cpu(hdr->req_id), le16_to_cpu(hdr->type),
                       range->start_addr, range->end_addr, free);

                prev_addr = range->end_addr;
                largest_hole = max(largest_hole, free);
        }
        free = priv->rx_end - prev_addr;
        largest_hole = max(largest_hole, free);
        printk(KERN_DEBUG "%s: \\ --- [free: %d], largest free block: %d ---\n",
               wiphy_name(priv->hw->wiphy), free, largest_hole);
        spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
}
#endif /* P54_MM_DEBUG */

/*
 * So, the firmware is somewhat stupid and doesn't know what places in its
 * memory incoming data should go to. By poking around in the firmware, we
 * can find some unused memory to upload our packets to. However, data that we
 * want the card to TX needs to stay intact until the card has told us that
 * it is done with it. This function finds empty places we can upload to and
 * marks allocated areas as reserved if necessary. p54_find_and_unlink_skb or
 * p54_free_skb frees allocated areas.
 */
static int p54_assign_address(struct p54_common *priv, struct sk_buff *skb)
{
        struct sk_buff *entry, *target_skb = NULL;
        struct ieee80211_tx_info *info;
        struct p54_tx_info *range;
        struct p54_hdr *data = (void *) skb->data;
        unsigned long flags;
        u32 last_addr = priv->rx_start;
        u32 target_addr = priv->rx_start;
        u16 len = priv->headroom + skb->len + priv->tailroom + 3;

        if (unlikely(WARN_ON(!skb || !priv)))
                return -EINVAL;

        info = IEEE80211_SKB_CB(skb);
        range = (void *) info->rate_driver_data;
        len = (range->extra_len + len) & ~0x3;

        spin_lock_irqsave(&priv->tx_queue.lock, flags);
        if (unlikely(skb_queue_len(&priv->tx_queue) == 32)) {
                /*
                 * The tx_queue is now really full.
                 *
                 * TODO: check if the device has crashed and reset it.
                 */
                spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
                return -EBUSY;
        }

        skb_queue_walk(&priv->tx_queue, entry) {
                u32 hole_size;
                info = IEEE80211_SKB_CB(entry);
                range = (void *) info->rate_driver_data;
                hole_size = range->start_addr - last_addr;

                if (!entry->next) {
                        spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
                        return -ENOSPC;
                }

                if (!target_skb && hole_size >= len) {
                        target_skb = entry->prev;
                        hole_size -= len;
                        target_addr = last_addr;
                        break;
                }
                last_addr = range->end_addr;
        }
        if (unlikely(!target_skb)) {
                if (priv->rx_end - last_addr >= len) {
                        target_skb = priv->tx_queue.prev;
                        if (!skb_queue_empty(&priv->tx_queue)) {
                                info = IEEE80211_SKB_CB(target_skb);
                                range = (void *)info->rate_driver_data;
                                target_addr = range->end_addr;
                        }
                } else {
                        spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
                        return -ENOSPC;
                }
        }

        info = IEEE80211_SKB_CB(skb);
        range = (void *) info->rate_driver_data;
        range->start_addr = target_addr;
        range->end_addr = target_addr + len;
        __skb_queue_after(&priv->tx_queue, target_skb, skb);
        spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
        data->req_id = cpu_to_le32(target_addr + priv->headroom);
        return 0;
}

static void p54_tx_pending(struct p54_common *priv)
{
        struct sk_buff *skb;
        int ret;

        if (unlikely(WARN_ON(!priv)))
                return ;

        skb = skb_dequeue(&priv->tx_pending);
        if (unlikely(!skb))
                return ;

        ret = p54_assign_address(priv, skb);
        if (unlikely(ret))
                skb_queue_head(&priv->tx_pending, skb);
        else
                priv->tx(priv->hw, skb);
}

static void p54_wake_queues(struct p54_common *priv)
{
        unsigned long flags;
        unsigned int i;

        if (unlikely(priv->mode == NL80211_IFTYPE_UNSPECIFIED))
                return ;

        p54_tx_pending(priv);

        spin_lock_irqsave(&priv->tx_stats_lock, flags);
        for (i = 0; i < priv->hw->queues; i++) {
                if (priv->tx_stats[i + P54_QUEUE_DATA].len <
                    priv->tx_stats[i + P54_QUEUE_DATA].limit)
                        ieee80211_wake_queue(priv->hw, i);
        }
        spin_unlock_irqrestore(&priv->tx_stats_lock, flags);
}

static int p54_tx_qos_accounting_alloc(struct p54_common *priv,
                                       struct sk_buff *skb,
                                       const u16 p54_queue)
{
        struct ieee80211_tx_queue_stats *queue;
        unsigned long flags;

        if (WARN_ON(p54_queue > P54_QUEUE_NUM))
                return -EINVAL;

        queue = &priv->tx_stats[p54_queue];

        spin_lock_irqsave(&priv->tx_stats_lock, flags);
        if (unlikely(queue->len > queue->limit && IS_QOS_QUEUE(p54_queue))) {
                spin_unlock_irqrestore(&priv->tx_stats_lock, flags);
                return -ENOSPC;
        }

        queue->len++;
        queue->count++;

        if (unlikely(queue->len == queue->limit && IS_QOS_QUEUE(p54_queue))) {
                u16 ac_queue = p54_queue - P54_QUEUE_DATA;
                ieee80211_stop_queue(priv->hw, ac_queue);
        }

        spin_unlock_irqrestore(&priv->tx_stats_lock, flags);
        return 0;
}

static void p54_tx_qos_accounting_free(struct p54_common *priv,
                                       struct sk_buff *skb)
{
        if (skb && IS_DATA_FRAME(skb)) {
                struct p54_hdr *hdr = (void *) skb->data;
                struct p54_tx_data *data = (void *) hdr->data;

                priv->tx_stats[data->hw_queue].len--;
        }
        p54_wake_queues(priv);
}

void p54_free_skb(struct ieee80211_hw *dev, struct sk_buff *skb)
{
        struct p54_common *priv = dev->priv;
        if (unlikely(!skb))
                return ;

        skb_unlink(skb, &priv->tx_queue);
        p54_tx_qos_accounting_free(priv, skb);
        dev_kfree_skb_any(skb);
}
EXPORT_SYMBOL_GPL(p54_free_skb);

static struct sk_buff *p54_find_and_unlink_skb(struct p54_common *priv,
                                               const __le32 req_id)
{
        struct sk_buff *entry;
        unsigned long flags;

        spin_lock_irqsave(&priv->tx_queue.lock, flags);
        skb_queue_walk(&priv->tx_queue, entry) {
                struct p54_hdr *hdr = (struct p54_hdr *) entry->data;

                if (hdr->req_id == req_id) {
                        __skb_unlink(entry, &priv->tx_queue);
                        spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
                        p54_tx_qos_accounting_free(priv, entry);
                        return entry;
                }
        }
        spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
        return NULL;
}

void p54_tx(struct p54_common *priv, struct sk_buff *skb)
{
        if (unlikely(WARN_ON(!priv)))
                return ;

        skb_queue_tail(&priv->tx_pending, skb);
        p54_tx_pending(priv);
}

static int p54_rssi_to_dbm(struct p54_common *priv, int rssi)
{
        int band = priv->hw->conf.channel->band;

        if (priv->rxhw != 5)
                return ((rssi * priv->rssical_db[band].mul) / 64 +
                         priv->rssical_db[band].add) / 4;
        else
                /*
                 * TODO: find the correct formula
                 */
                return ((rssi * priv->rssical_db[band].mul) / 64 +
                         priv->rssical_db[band].add) / 4;
}

static int p54_rx_data(struct p54_common *priv, struct sk_buff *skb)
{
        struct p54_rx_data *hdr = (struct p54_rx_data *) skb->data;
        struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
        u16 freq = le16_to_cpu(hdr->freq);
        size_t header_len = sizeof(*hdr);
        u32 tsf32;
        u8 rate = hdr->rate & 0xf;

        /*
         * If the device is in a unspecified state we have to
         * ignore all data frames. Else we could end up with a
         * nasty crash.
         */
        if (unlikely(priv->mode == NL80211_IFTYPE_UNSPECIFIED))
                return 0;

        if (!(hdr->flags & cpu_to_le16(P54_HDR_FLAG_DATA_IN_FCS_GOOD)))
                return 0;

        if (hdr->decrypt_status == P54_DECRYPT_OK)
                rx_status->flag |= RX_FLAG_DECRYPTED;
        if ((hdr->decrypt_status == P54_DECRYPT_FAIL_MICHAEL) ||
            (hdr->decrypt_status == P54_DECRYPT_FAIL_TKIP))
                rx_status->flag |= RX_FLAG_MMIC_ERROR;

        rx_status->signal = p54_rssi_to_dbm(priv, hdr->rssi);
        rx_status->noise = priv->noise;
        if (hdr->rate & 0x10)
                rx_status->flag |= RX_FLAG_SHORTPRE;
        if (priv->hw->conf.channel->band == IEEE80211_BAND_5GHZ)
                rx_status->rate_idx = (rate < 4) ? 0 : rate - 4;
        else
                rx_status->rate_idx = rate;

        rx_status->freq = freq;
        rx_status->band =  priv->hw->conf.channel->band;
        rx_status->antenna = hdr->antenna;

        tsf32 = le32_to_cpu(hdr->tsf32);
        if (tsf32 < priv->tsf_low32)
                priv->tsf_high32++;
        rx_status->mactime = ((u64)priv->tsf_high32) << 32 | tsf32;
        priv->tsf_low32 = tsf32;

        rx_status->flag |= RX_FLAG_TSFT;

        if (hdr->flags & cpu_to_le16(P54_HDR_FLAG_DATA_ALIGN))
                header_len += hdr->align[0];

        skb_pull(skb, header_len);
        skb_trim(skb, le16_to_cpu(hdr->len));
        ieee80211_rx_irqsafe(priv->hw, skb);

        queue_delayed_work(priv->hw->workqueue, &priv->work,
                           msecs_to_jiffies(P54_STATISTICS_UPDATE));

        return -1;
}

static void p54_rx_frame_sent(struct p54_common *priv, struct sk_buff *skb)
{
        struct p54_hdr *hdr = (struct p54_hdr *) skb->data;
        struct p54_frame_sent *payload = (struct p54_frame_sent *) hdr->data;
        struct ieee80211_tx_info *info;
        struct p54_hdr *entry_hdr;
        struct p54_tx_data *entry_data;
        struct sk_buff *entry;
        unsigned int pad = 0, frame_len;
        int count, idx;

        entry = p54_find_and_unlink_skb(priv, hdr->req_id);
        if (unlikely(!entry))
                return ;

        frame_len = entry->len;
        info = IEEE80211_SKB_CB(entry);
        entry_hdr = (struct p54_hdr *) entry->data;
        entry_data = (struct p54_tx_data *) entry_hdr->data;
        priv->stats.dot11ACKFailureCount += payload->tries - 1;

        /*
         * Frames in P54_QUEUE_FWSCAN and P54_QUEUE_BEACON are
         * generated by the driver. Therefore tx_status is bogus
         * and we don't want to confuse the mac80211 stack.
         */
        if (unlikely(entry_data->hw_queue < P54_QUEUE_FWSCAN)) {
                if (entry_data->hw_queue == P54_QUEUE_BEACON &&
                    hdr->req_id == priv->beacon_req_id)
                        priv->beacon_req_id = cpu_to_le32(0);

                dev_kfree_skb_any(entry);
                return ;
        }

        /*
         * Clear manually, ieee80211_tx_info_clear_status would
         * clear the counts too and we need them.
         */
        memset(&info->status.ampdu_ack_len, 0,
               sizeof(struct ieee80211_tx_info) -
               offsetof(struct ieee80211_tx_info, status.ampdu_ack_len));
        BUILD_BUG_ON(offsetof(struct ieee80211_tx_info,
                              status.ampdu_ack_len) != 23);

        if (entry_hdr->flags & cpu_to_le16(P54_HDR_FLAG_DATA_ALIGN))
                pad = entry_data->align[0];

        /* walk through the rates array and adjust the counts */
        count = payload->tries;
        for (idx = 0; idx < 4; idx++) {
                if (count >= info->status.rates[idx].count) {
                        count -= info->status.rates[idx].count;
                } else if (count > 0) {
                        info->status.rates[idx].count = count;
                        count = 0;
                } else {
                        info->status.rates[idx].idx = -1;
                        info->status.rates[idx].count = 0;
                }
        }

        if (!(info->flags & IEEE80211_TX_CTL_NO_ACK) &&
             (!payload->status))
                info->flags |= IEEE80211_TX_STAT_ACK;
        if (payload->status & P54_TX_PSM_CANCELLED)
                info->flags |= IEEE80211_TX_STAT_TX_FILTERED;
        info->status.ack_signal = p54_rssi_to_dbm(priv,
                                                  (int)payload->ack_rssi);

        /* Undo all changes to the frame. */
        switch (entry_data->key_type) {
        case P54_CRYPTO_TKIPMICHAEL: {
                u8 *iv = (u8 *)(entry_data->align + pad +
                                entry_data->crypt_offset);

                /* Restore the original TKIP IV. */
                iv[2] = iv[0];
                iv[0] = iv[1];
                iv[1] = (iv[0] | 0x20) & 0x7f;  /* WEPSeed - 8.3.2.2 */

                frame_len -= 12; /* remove TKIP_MMIC + TKIP_ICV */
                break;
                }
        case P54_CRYPTO_AESCCMP:
                frame_len -= 8; /* remove CCMP_MIC */
                break;
        case P54_CRYPTO_WEP:
                frame_len -= 4; /* remove WEP_ICV */
                break;
        }

        skb_trim(entry, frame_len);
        skb_pull(entry, sizeof(*hdr) + pad + sizeof(*entry_data));
        ieee80211_tx_status_irqsafe(priv->hw, entry);
}

static void p54_rx_eeprom_readback(struct p54_common *priv,
                                   struct sk_buff *skb)
{
        struct p54_hdr *hdr = (struct p54_hdr *) skb->data;
        struct p54_eeprom_lm86 *eeprom = (struct p54_eeprom_lm86 *) hdr->data;
        struct sk_buff *tmp;

        if (!priv->eeprom)
                return ;

        if (priv->fw_var >= 0x509) {
                memcpy(priv->eeprom, eeprom->v2.data,
                       le16_to_cpu(eeprom->v2.len));
        } else {
                memcpy(priv->eeprom, eeprom->v1.data,
                       le16_to_cpu(eeprom->v1.len));
        }

        priv->eeprom = NULL;
        tmp = p54_find_and_unlink_skb(priv, hdr->req_id);
        p54_tx_qos_accounting_free(priv, tmp);
        dev_kfree_skb_any(tmp);
        complete(&priv->eeprom_comp);
}

static void p54_rx_stats(struct p54_common *priv, struct sk_buff *skb)
{
        struct p54_hdr *hdr = (struct p54_hdr *) skb->data;
        struct p54_statistics *stats = (struct p54_statistics *) hdr->data;
        struct sk_buff *tmp;
        u32 tsf32;

        if (unlikely(priv->mode == NL80211_IFTYPE_UNSPECIFIED))
                return ;

        tsf32 = le32_to_cpu(stats->tsf32);
        if (tsf32 < priv->tsf_low32)
                priv->tsf_high32++;
        priv->tsf_low32 = tsf32;

        priv->stats.dot11RTSFailureCount = le32_to_cpu(stats->rts_fail);
        priv->stats.dot11RTSSuccessCount = le32_to_cpu(stats->rts_success);
        priv->stats.dot11FCSErrorCount = le32_to_cpu(stats->rx_bad_fcs);

        priv->noise = p54_rssi_to_dbm(priv, le32_to_cpu(stats->noise));

        tmp = p54_find_and_unlink_skb(priv, hdr->req_id);
        p54_tx_qos_accounting_free(priv, tmp);
        dev_kfree_skb_any(tmp);
}

static void p54_rx_trap(struct p54_common *priv, struct sk_buff *skb)
{
        struct p54_hdr *hdr = (struct p54_hdr *) skb->data;
        struct p54_trap *trap = (struct p54_trap *) hdr->data;
        u16 event = le16_to_cpu(trap->event);
        u16 freq = le16_to_cpu(trap->frequency);

        switch (event) {
        case P54_TRAP_BEACON_TX:
                break;
        case P54_TRAP_RADAR:
                printk(KERN_INFO "%s: radar (freq:%d MHz)\n",
                        wiphy_name(priv->hw->wiphy), freq);
                break;
        case P54_TRAP_NO_BEACON:
                if (priv->vif)
                        ieee80211_beacon_loss(priv->vif);
                break;
        case P54_TRAP_SCAN:
                break;
        case P54_TRAP_TBTT:
                break;
        case P54_TRAP_TIMER:
                break;
        default:
                printk(KERN_INFO "%s: received event:%x freq:%d\n",
                       wiphy_name(priv->hw->wiphy), event, freq);
                break;
        }
}

static int p54_rx_control(struct p54_common *priv, struct sk_buff *skb)
{
        struct p54_hdr *hdr = (struct p54_hdr *) skb->data;

        switch (le16_to_cpu(hdr->type)) {
        case P54_CONTROL_TYPE_TXDONE:
                p54_rx_frame_sent(priv, skb);
                break;
        case P54_CONTROL_TYPE_TRAP:
                p54_rx_trap(priv, skb);
                break;
        case P54_CONTROL_TYPE_BBP:
                break;
        case P54_CONTROL_TYPE_STAT_READBACK:
                p54_rx_stats(priv, skb);
                break;
        case P54_CONTROL_TYPE_EEPROM_READBACK:
                p54_rx_eeprom_readback(priv, skb);
                break;
        default:
                printk(KERN_DEBUG "%s: not handling 0x%02x type control frame\n",
                       wiphy_name(priv->hw->wiphy), le16_to_cpu(hdr->type));
                break;
        }
        return 0;
}

/* returns zero if skb can be reused */
int p54_rx(struct ieee80211_hw *dev, struct sk_buff *skb)
{
        struct p54_common *priv = dev->priv;
        u16 type = le16_to_cpu(*((__le16 *)skb->data));

        if (type & P54_HDR_FLAG_CONTROL)
                return p54_rx_control(priv, skb);
        else
                return p54_rx_data(priv, skb);
}
EXPORT_SYMBOL_GPL(p54_rx);

static void p54_tx_80211_header(struct p54_common *priv, struct sk_buff *skb,
                                struct ieee80211_tx_info *info, u8 *queue,
                                u32 *extra_len, u16 *flags, u16 *aid,
                                bool *burst_possible)
{
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;

        if (ieee80211_is_data_qos(hdr->frame_control))
                *burst_possible = true;
        else
                *burst_possible = false;

        if (info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ)
                *flags |= P54_HDR_FLAG_DATA_OUT_SEQNR;

        if (info->flags & IEEE80211_TX_CTL_CLEAR_PS_FILT)
                *flags |= P54_HDR_FLAG_DATA_OUT_NOCANCEL;

        *queue = skb_get_queue_mapping(skb) + P54_QUEUE_DATA;

        switch (priv->mode) {
        case NL80211_IFTYPE_MONITOR:
                /*
                 * We have to set P54_HDR_FLAG_DATA_OUT_PROMISC for
                 * every frame in promiscuous/monitor mode.
                 * see STSW45x0C LMAC API - page 12.
                 */
                *aid = 0;
                *flags |= P54_HDR_FLAG_DATA_OUT_PROMISC;
                break;
        case NL80211_IFTYPE_STATION:
                *aid = 1;
                break;
        case NL80211_IFTYPE_AP:
        case NL80211_IFTYPE_ADHOC:
        case NL80211_IFTYPE_MESH_POINT:
                if (info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM) {
                        *aid = 0;
                        *queue = P54_QUEUE_CAB;
                        return;
                }

                if (unlikely(ieee80211_is_mgmt(hdr->frame_control))) {
                        if (ieee80211_is_probe_resp(hdr->frame_control)) {
                                *aid = 0;
                                *flags |= P54_HDR_FLAG_DATA_OUT_TIMESTAMP |
                                          P54_HDR_FLAG_DATA_OUT_NOCANCEL;
                                return;
                        } else if (ieee80211_is_beacon(hdr->frame_control)) {
                                *aid = 0;

                                if (info->flags & IEEE80211_TX_CTL_INJECTED) {
                                        /*
                                         * Injecting beacons on top of a AP is
                                         * not a good idea... nevertheless,
                                         * it should be doable.
                                         */

                                        return;
                                }

                                *flags |= P54_HDR_FLAG_DATA_OUT_TIMESTAMP;
                                *queue = P54_QUEUE_BEACON;
                                *extra_len = IEEE80211_MAX_TIM_LEN;
                                return;
                        }
                }

                if (info->control.sta)
                        *aid = info->control.sta->aid;
                break;
        }
}

static u8 p54_convert_algo(enum ieee80211_key_alg alg)
{
        switch (alg) {
        case ALG_WEP:
                return P54_CRYPTO_WEP;
        case ALG_TKIP:
                return P54_CRYPTO_TKIPMICHAEL;
        case ALG_CCMP:
                return P54_CRYPTO_AESCCMP;
        default:
                return 0;
        }
}

int p54_tx_80211(struct ieee80211_hw *dev, struct sk_buff *skb)
{
        struct p54_common *priv = dev->priv;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct p54_tx_info *p54info;
        struct p54_hdr *hdr;
        struct p54_tx_data *txhdr;
        unsigned int padding, len, extra_len;
        int i, j, ridx;
        u16 hdr_flags = 0, aid = 0;
        u8 rate, queue = 0, crypt_offset = 0;
        u8 cts_rate = 0x20;
        u8 rc_flags;
        u8 calculated_tries[4];
        u8 nrates = 0, nremaining = 8;
        bool burst_allowed = false;

        p54_tx_80211_header(priv, skb, info, &queue, &extra_len,
                            &hdr_flags, &aid, &burst_allowed);

        if (p54_tx_qos_accounting_alloc(priv, skb, queue)) {
                if (!IS_QOS_QUEUE(queue)) {
                        dev_kfree_skb_any(skb);
                        return NETDEV_TX_OK;
                } else {
                        return NETDEV_TX_BUSY;
                }
        }

        padding = (unsigned long)(skb->data - (sizeof(*hdr) + sizeof(*txhdr))) & 3;
        len = skb->len;

        if (info->control.hw_key) {
                crypt_offset = ieee80211_get_hdrlen_from_skb(skb);
                if (info->control.hw_key->alg == ALG_TKIP) {
                        u8 *iv = (u8 *)(skb->data + crypt_offset);
                        /*
                         * The firmware excepts that the IV has to have
                         * this special format
                         */
                        iv[1] = iv[0];
                        iv[0] = iv[2];
                        iv[2] = 0;
                }
        }

        txhdr = (struct p54_tx_data *) skb_push(skb, sizeof(*txhdr) + padding);
        hdr = (struct p54_hdr *) skb_push(skb, sizeof(*hdr));

        if (padding)
                hdr_flags |= P54_HDR_FLAG_DATA_ALIGN;
        hdr->type = cpu_to_le16(aid);
        hdr->rts_tries = info->control.rates[0].count;

        /*
         * we register the rates in perfect order, and
         * RTS/CTS won't happen on 5 GHz
         */
        cts_rate = info->control.rts_cts_rate_idx;

        memset(&txhdr->rateset, 0, sizeof(txhdr->rateset));

        /* see how many rates got used */
        for (i = 0; i < dev->max_rates; i++) {
                if (info->control.rates[i].idx < 0)
                        break;
                nrates++;
        }

        /* limit tries to 8/nrates per rate */
        for (i = 0; i < nrates; i++) {
                /*
                 * The magic expression here is equivalent to 8/nrates for
                 * all values that matter, but avoids division and jumps.
                 * Note that nrates can only take the values 1 through 4.
                 */
                calculated_tries[i] = min_t(int, ((15 >> nrates) | 1) + 1,
                                                 info->control.rates[i].count);
                nremaining -= calculated_tries[i];
        }

        /* if there are tries left, distribute from back to front */
        for (i = nrates - 1; nremaining > 0 && i >= 0; i--) {
                int tmp = info->control.rates[i].count - calculated_tries[i];

                if (tmp <= 0)
                        continue;
                /* RC requested more tries at this rate */

                tmp = min_t(int, tmp, nremaining);
                calculated_tries[i] += tmp;
                nremaining -= tmp;
        }

        ridx = 0;
        for (i = 0; i < nrates && ridx < 8; i++) {
                /* we register the rates in perfect order */
                rate = info->control.rates[i].idx;
                if (info->band == IEEE80211_BAND_5GHZ)
                        rate += 4;

                /* store the count we actually calculated for TX status */
                info->control.rates[i].count = calculated_tries[i];

                rc_flags = info->control.rates[i].flags;
                if (rc_flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE) {
                        rate |= 0x10;
                        cts_rate |= 0x10;
                }
                if (rc_flags & IEEE80211_TX_RC_USE_RTS_CTS) {
                        burst_allowed = false;
                        rate |= 0x40;
                } else if (rc_flags & IEEE80211_TX_RC_USE_CTS_PROTECT) {
                        rate |= 0x20;
                        burst_allowed = false;
                }
                for (j = 0; j < calculated_tries[i] && ridx < 8; j++) {
                        txhdr->rateset[ridx] = rate;
                        ridx++;
                }
        }

        if (burst_allowed)
                hdr_flags |= P54_HDR_FLAG_DATA_OUT_BURST;

        /* TODO: enable bursting */
        hdr->flags = cpu_to_le16(hdr_flags);
        hdr->tries = ridx;
        txhdr->rts_rate_idx = 0;
        if (info->control.hw_key) {
                txhdr->key_type = p54_convert_algo(info->control.hw_key->alg);
                txhdr->key_len = min((u8)16, info->control.hw_key->keylen);
                memcpy(txhdr->key, info->control.hw_key->key, txhdr->key_len);
                if (info->control.hw_key->alg == ALG_TKIP) {
                        /* reserve space for the MIC key */
                        len += 8;
                        memcpy(skb_put(skb, 8), &(info->control.hw_key->key
                                [NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY]), 8);
                }
                /* reserve some space for ICV */
                len += info->control.hw_key->icv_len;
                memset(skb_put(skb, info->control.hw_key->icv_len), 0,
                       info->control.hw_key->icv_len);
        } else {
                txhdr->key_type = 0;
                txhdr->key_len = 0;
        }
        txhdr->crypt_offset = crypt_offset;
        txhdr->hw_queue = queue;
        txhdr->backlog = priv->tx_stats[queue].len - 1;
        memset(txhdr->durations, 0, sizeof(txhdr->durations));
        txhdr->tx_antenna = ((info->antenna_sel_tx == 0) ?
                2 : info->antenna_sel_tx - 1) & priv->tx_diversity_mask;
        if (priv->rxhw == 5) {
                txhdr->longbow.cts_rate = cts_rate;
                txhdr->longbow.output_power = cpu_to_le16(priv->output_power);
        } else {
                txhdr->normal.output_power = priv->output_power;
                txhdr->normal.cts_rate = cts_rate;
        }
        if (padding)
                txhdr->align[0] = padding;

        hdr->len = cpu_to_le16(len);
        /* modifies skb->cb and with it info, so must be last! */
        p54info = (void *) info->rate_driver_data;
        p54info->extra_len = extra_len;

        p54_tx(priv, skb);
        return NETDEV_TX_OK;
}