[safe/jmp/linux-2.6] / drivers / net / wireless / rt2x00 / rt2x00dev.c

/*
        Copyright (C) 2004 - 2008 rt2x00 SourceForge Project
        <http://rt2x00.serialmonkey.com>

        This program is free software; you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation; either version 2 of the License, or
        (at your option) any later version.

        This program is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
        GNU General Public License for more details.

        You should have received a copy of the GNU General Public License
        along with this program; if not, write to the
        Free Software Foundation, Inc.,
        59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*
        Module: rt2x00lib
        Abstract: rt2x00 generic device routines.
 */

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

#include "rt2x00.h"
#include "rt2x00lib.h"
#include "rt2x00dump.h"

/*
 * Link tuning handlers
 */
void rt2x00lib_reset_link_tuner(struct rt2x00_dev *rt2x00dev)
{
        if (!test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags))
                return;

        /*
         * Reset link information.
         * Both the currently active vgc level as well as
         * the link tuner counter should be reset. Resetting
         * the counter is important for devices where the
         * device should only perform link tuning during the
         * first minute after being enabled.
         */
        rt2x00dev->link.count = 0;
        rt2x00dev->link.vgc_level = 0;

        /*
         * Reset the link tuner.
         */
        rt2x00dev->ops->lib->reset_tuner(rt2x00dev);
}

static void rt2x00lib_start_link_tuner(struct rt2x00_dev *rt2x00dev)
{
        /*
         * Clear all (possibly) pre-existing quality statistics.
         */
        memset(&rt2x00dev->link.qual, 0, sizeof(rt2x00dev->link.qual));

        /*
         * The RX and TX percentage should start at 50%
         * this will assure we will get at least get some
         * decent value when the link tuner starts.
         * The value will be dropped and overwritten with
         * the correct (measured )value anyway during the
         * first run of the link tuner.
         */
        rt2x00dev->link.qual.rx_percentage = 50;
        rt2x00dev->link.qual.tx_percentage = 50;

        rt2x00lib_reset_link_tuner(rt2x00dev);

        queue_delayed_work(rt2x00dev->hw->workqueue,
                           &rt2x00dev->link.work, LINK_TUNE_INTERVAL);
}

static void rt2x00lib_stop_link_tuner(struct rt2x00_dev *rt2x00dev)
{
        cancel_delayed_work_sync(&rt2x00dev->link.work);
}

/*
 * Radio control handlers.
 */
int rt2x00lib_enable_radio(struct rt2x00_dev *rt2x00dev)
{
        int status;

        /*
         * Don't enable the radio twice.
         * And check if the hardware button has been disabled.
         */
        if (test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags) ||
            test_bit(DEVICE_DISABLED_RADIO_HW, &rt2x00dev->flags))
                return 0;

        /*
         * Initialize all data queues.
         */
        rt2x00queue_init_rx(rt2x00dev);
        rt2x00queue_init_tx(rt2x00dev);

        /*
         * Enable radio.
         */
        status = rt2x00dev->ops->lib->set_device_state(rt2x00dev,
                                                       STATE_RADIO_ON);
        if (status)
                return status;

        __set_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags);

        /*
         * Enable RX.
         */
        rt2x00lib_toggle_rx(rt2x00dev, STATE_RADIO_RX_ON);

        /*
         * Start the TX queues.
         */
        ieee80211_start_queues(rt2x00dev->hw);

        return 0;
}

void rt2x00lib_disable_radio(struct rt2x00_dev *rt2x00dev)
{
        if (!__test_and_clear_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags))
                return;

        /*
         * Stop all scheduled work.
         */
        if (work_pending(&rt2x00dev->intf_work))
                cancel_work_sync(&rt2x00dev->intf_work);
        if (work_pending(&rt2x00dev->filter_work))
                cancel_work_sync(&rt2x00dev->filter_work);

        /*
         * Stop the TX queues.
         */
        ieee80211_stop_queues(rt2x00dev->hw);

        /*
         * Disable RX.
         */
        rt2x00lib_toggle_rx(rt2x00dev, STATE_RADIO_RX_OFF);

        /*
         * Disable radio.
         */
        rt2x00dev->ops->lib->set_device_state(rt2x00dev, STATE_RADIO_OFF);
}

void rt2x00lib_toggle_rx(struct rt2x00_dev *rt2x00dev, enum dev_state state)
{
        /*
         * When we are disabling the RX, we should also stop the link tuner.
         */
        if (state == STATE_RADIO_RX_OFF)
                rt2x00lib_stop_link_tuner(rt2x00dev);

        rt2x00dev->ops->lib->set_device_state(rt2x00dev, state);

        /*
         * When we are enabling the RX, we should also start the link tuner.
         */
        if (state == STATE_RADIO_RX_ON &&
            (rt2x00dev->intf_ap_count || rt2x00dev->intf_sta_count))
                rt2x00lib_start_link_tuner(rt2x00dev);
}

static void rt2x00lib_evaluate_antenna_sample(struct rt2x00_dev *rt2x00dev)
{
        enum antenna rx = rt2x00dev->link.ant.active.rx;
        enum antenna tx = rt2x00dev->link.ant.active.tx;
        int sample_a =
            rt2x00_get_link_ant_rssi_history(&rt2x00dev->link, ANTENNA_A);
        int sample_b =
            rt2x00_get_link_ant_rssi_history(&rt2x00dev->link, ANTENNA_B);

        /*
         * We are done sampling. Now we should evaluate the results.
         */
        rt2x00dev->link.ant.flags &= ~ANTENNA_MODE_SAMPLE;

        /*
         * During the last period we have sampled the RSSI
         * from both antenna's. It now is time to determine
         * which antenna demonstrated the best performance.
         * When we are already on the antenna with the best
         * performance, then there really is nothing for us
         * left to do.
         */
        if (sample_a == sample_b)
                return;

        if (rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY)
                rx = (sample_a > sample_b) ? ANTENNA_A : ANTENNA_B;

        if (rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY)
                tx = (sample_a > sample_b) ? ANTENNA_A : ANTENNA_B;

        rt2x00lib_config_antenna(rt2x00dev, rx, tx);
}

static void rt2x00lib_evaluate_antenna_eval(struct rt2x00_dev *rt2x00dev)
{
        enum antenna rx = rt2x00dev->link.ant.active.rx;
        enum antenna tx = rt2x00dev->link.ant.active.tx;
        int rssi_curr = rt2x00_get_link_ant_rssi(&rt2x00dev->link);
        int rssi_old = rt2x00_update_ant_rssi(&rt2x00dev->link, rssi_curr);

        /*
         * Legacy driver indicates that we should swap antenna's
         * when the difference in RSSI is greater that 5. This
         * also should be done when the RSSI was actually better
         * then the previous sample.
         * When the difference exceeds the threshold we should
         * sample the rssi from the other antenna to make a valid
         * comparison between the 2 antennas.
         */
        if (abs(rssi_curr - rssi_old) < 5)
                return;

        rt2x00dev->link.ant.flags |= ANTENNA_MODE_SAMPLE;

        if (rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY)
                rx = (rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;

        if (rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY)
                tx = (tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;

        rt2x00lib_config_antenna(rt2x00dev, rx, tx);
}

static void rt2x00lib_evaluate_antenna(struct rt2x00_dev *rt2x00dev)
{
        /*
         * Determine if software diversity is enabled for
         * either the TX or RX antenna (or both).
         * Always perform this check since within the link
         * tuner interval the configuration might have changed.
         */
        rt2x00dev->link.ant.flags &= ~ANTENNA_RX_DIVERSITY;
        rt2x00dev->link.ant.flags &= ~ANTENNA_TX_DIVERSITY;

        if (rt2x00dev->hw->conf.antenna_sel_rx == 0 &&
            rt2x00dev->default_ant.rx == ANTENNA_SW_DIVERSITY)
                rt2x00dev->link.ant.flags |= ANTENNA_RX_DIVERSITY;
        if (rt2x00dev->hw->conf.antenna_sel_tx == 0 &&
            rt2x00dev->default_ant.tx == ANTENNA_SW_DIVERSITY)
                rt2x00dev->link.ant.flags |= ANTENNA_TX_DIVERSITY;

        if (!(rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY) &&
            !(rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY)) {
                rt2x00dev->link.ant.flags = 0;
                return;
        }

        /*
         * If we have only sampled the data over the last period
         * we should now harvest the data. Otherwise just evaluate
         * the data. The latter should only be performed once
         * every 2 seconds.
         */
        if (rt2x00dev->link.ant.flags & ANTENNA_MODE_SAMPLE)
                rt2x00lib_evaluate_antenna_sample(rt2x00dev);
        else if (rt2x00dev->link.count & 1)
                rt2x00lib_evaluate_antenna_eval(rt2x00dev);
}

static void rt2x00lib_update_link_stats(struct link *link, int rssi)
{
        int avg_rssi = rssi;

        /*
         * Update global RSSI
         */
        if (link->qual.avg_rssi)
                avg_rssi = MOVING_AVERAGE(link->qual.avg_rssi, rssi, 8);
        link->qual.avg_rssi = avg_rssi;

        /*
         * Update antenna RSSI
         */
        if (link->ant.rssi_ant)
                rssi = MOVING_AVERAGE(link->ant.rssi_ant, rssi, 8);
        link->ant.rssi_ant = rssi;
}

static void rt2x00lib_precalculate_link_signal(struct link_qual *qual)
{
        if (qual->rx_failed || qual->rx_success)
                qual->rx_percentage =
                    (qual->rx_success * 100) /
                    (qual->rx_failed + qual->rx_success);
        else
                qual->rx_percentage = 50;

        if (qual->tx_failed || qual->tx_success)
                qual->tx_percentage =
                    (qual->tx_success * 100) /
                    (qual->tx_failed + qual->tx_success);
        else
                qual->tx_percentage = 50;

        qual->rx_success = 0;
        qual->rx_failed = 0;
        qual->tx_success = 0;
        qual->tx_failed = 0;
}

static int rt2x00lib_calculate_link_signal(struct rt2x00_dev *rt2x00dev,
                                           int rssi)
{
        int rssi_percentage = 0;
        int signal;

        /*
         * We need a positive value for the RSSI.
         */
        if (rssi < 0)
                rssi += rt2x00dev->rssi_offset;

        /*
         * Calculate the different percentages,
         * which will be used for the signal.
         */
        if (rt2x00dev->rssi_offset)
                rssi_percentage = (rssi * 100) / rt2x00dev->rssi_offset;

        /*
         * Add the individual percentages and use the WEIGHT
         * defines to calculate the current link signal.
         */
        signal = ((WEIGHT_RSSI * rssi_percentage) +
                  (WEIGHT_TX * rt2x00dev->link.qual.tx_percentage) +
                  (WEIGHT_RX * rt2x00dev->link.qual.rx_percentage)) / 100;

        return (signal > 100) ? 100 : signal;
}

static void rt2x00lib_link_tuner(struct work_struct *work)
{
        struct rt2x00_dev *rt2x00dev =
            container_of(work, struct rt2x00_dev, link.work.work);

        /*
         * When the radio is shutting down we should
         * immediately cease all link tuning.
         */
        if (!test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags))
                return;

        /*
         * Update statistics.
         */
        rt2x00dev->ops->lib->link_stats(rt2x00dev, &rt2x00dev->link.qual);
        rt2x00dev->low_level_stats.dot11FCSErrorCount +=
            rt2x00dev->link.qual.rx_failed;

        /*
         * Only perform the link tuning when Link tuning
         * has been enabled (This could have been disabled from the EEPROM).
         */
        if (!test_bit(CONFIG_DISABLE_LINK_TUNING, &rt2x00dev->flags))
                rt2x00dev->ops->lib->link_tuner(rt2x00dev);

        /*
         * Precalculate a portion of the link signal which is
         * in based on the tx/rx success/failure counters.
         */
        rt2x00lib_precalculate_link_signal(&rt2x00dev->link.qual);

        /*
         * Send a signal to the led to update the led signal strength.
         */
        rt2x00leds_led_quality(rt2x00dev, rt2x00dev->link.qual.avg_rssi);

        /*
         * Evaluate antenna setup, make this the last step since this could
         * possibly reset some statistics.
         */
        rt2x00lib_evaluate_antenna(rt2x00dev);

        /*
         * Increase tuner counter, and reschedule the next link tuner run.
         */
        rt2x00dev->link.count++;
        queue_delayed_work(rt2x00dev->hw->workqueue, &rt2x00dev->link.work,
                           LINK_TUNE_INTERVAL);
}

static void rt2x00lib_packetfilter_scheduled(struct work_struct *work)
{
        struct rt2x00_dev *rt2x00dev =
            container_of(work, struct rt2x00_dev, filter_work);
        unsigned int filter = rt2x00dev->packet_filter;

        /*
         * Since we had stored the filter inside rt2x00dev->packet_filter,
         * we should now clear that field. Otherwise the driver will
         * assume nothing has changed (*total_flags will be compared
         * to rt2x00dev->packet_filter to determine if any action is required).
         */
        rt2x00dev->packet_filter = 0;

        rt2x00dev->ops->hw->configure_filter(rt2x00dev->hw,
                                             filter, &filter, 0, NULL);
}

static void rt2x00lib_intf_scheduled_iter(void *data, u8 *mac,
                                          struct ieee80211_vif *vif)
{
        struct rt2x00_dev *rt2x00dev = data;
        struct rt2x00_intf *intf = vif_to_intf(vif);
        struct sk_buff *skb;
        struct ieee80211_tx_control control;
        struct ieee80211_bss_conf conf;
        int delayed_flags;

        /*
         * Copy all data we need during this action under the protection
         * of a spinlock. Otherwise race conditions might occur which results
         * into an invalid configuration.
         */
        spin_lock(&intf->lock);

        memcpy(&conf, &intf->conf, sizeof(conf));
        delayed_flags = intf->delayed_flags;
        intf->delayed_flags = 0;

        spin_unlock(&intf->lock);

        if (delayed_flags & DELAYED_UPDATE_BEACON) {
                skb = ieee80211_beacon_get(rt2x00dev->hw, vif, &control);
                if (skb) {
                        rt2x00dev->ops->hw->beacon_update(rt2x00dev->hw, skb,
                                                          &control);
                        dev_kfree_skb(skb);
                }
        }

        if (delayed_flags & DELAYED_CONFIG_PREAMBLE)
                rt2x00lib_config_preamble(rt2x00dev, intf,
                                          intf->conf.use_short_preamble);
}

static void rt2x00lib_intf_scheduled(struct work_struct *work)
{
        struct rt2x00_dev *rt2x00dev =
            container_of(work, struct rt2x00_dev, intf_work);

        /*
         * Iterate over each interface and perform the
         * requested configurations.
         */
        ieee80211_iterate_active_interfaces(rt2x00dev->hw,
                                            rt2x00lib_intf_scheduled_iter,
                                            rt2x00dev);
}

/*
 * Interrupt context handlers.
 */
static void rt2x00lib_beacondone_iter(void *data, u8 *mac,
                                      struct ieee80211_vif *vif)
{
        struct rt2x00_intf *intf = vif_to_intf(vif);

        if (vif->type != IEEE80211_IF_TYPE_AP &&
            vif->type != IEEE80211_IF_TYPE_IBSS)
                return;

        spin_lock(&intf->lock);
        intf->delayed_flags |= DELAYED_UPDATE_BEACON;
        spin_unlock(&intf->lock);
}

void rt2x00lib_beacondone(struct rt2x00_dev *rt2x00dev)
{
        if (!test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags))
                return;

        ieee80211_iterate_active_interfaces(rt2x00dev->hw,
                                            rt2x00lib_beacondone_iter,
                                            rt2x00dev);

        queue_work(rt2x00dev->hw->workqueue, &rt2x00dev->intf_work);
}
EXPORT_SYMBOL_GPL(rt2x00lib_beacondone);

void rt2x00lib_txdone(struct queue_entry *entry,
                      struct txdone_entry_desc *txdesc)
{
        struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
        struct skb_frame_desc *skbdesc;
        struct ieee80211_tx_status tx_status;
        int success = !!(txdesc->status == TX_SUCCESS ||
                         txdesc->status == TX_SUCCESS_RETRY);
        int fail = !!(txdesc->status == TX_FAIL_RETRY ||
                      txdesc->status == TX_FAIL_INVALID ||
                      txdesc->status == TX_FAIL_OTHER);

        /*
         * Update TX statistics.
         */
        rt2x00dev->link.qual.tx_success += success;
        rt2x00dev->link.qual.tx_failed += txdesc->retry + fail;

        /*
         * Initialize TX status
         */
        tx_status.flags = 0;
        tx_status.ack_signal = 0;
        tx_status.excessive_retries = (txdesc->status == TX_FAIL_RETRY);
        tx_status.retry_count = txdesc->retry;
        memcpy(&tx_status.control, txdesc->control, sizeof(*txdesc->control));

        if (!(tx_status.control.flags & IEEE80211_TXCTL_NO_ACK)) {
                if (success)
                        tx_status.flags |= IEEE80211_TX_STATUS_ACK;
                else
                        rt2x00dev->low_level_stats.dot11ACKFailureCount++;
        }

        tx_status.queue_length = entry->queue->limit;
        tx_status.queue_number = tx_status.control.queue;

        if (tx_status.control.flags & IEEE80211_TXCTL_USE_RTS_CTS) {
                if (success)
                        rt2x00dev->low_level_stats.dot11RTSSuccessCount++;
                else
                        rt2x00dev->low_level_stats.dot11RTSFailureCount++;
        }

        /*
         * Send the tx_status to debugfs. Only send the status report
         * to mac80211 when the frame originated from there. If this was
         * a extra frame coming through a mac80211 library call (RTS/CTS)
         * then we should not send the status report back.
         * If send to mac80211, mac80211 will clean up the skb structure,
         * otherwise we have to do it ourself.
         */
        skbdesc = get_skb_frame_desc(entry->skb);
        skbdesc->frame_type = DUMP_FRAME_TXDONE;

        rt2x00debug_dump_frame(rt2x00dev, entry->skb);

        if (!(skbdesc->flags & FRAME_DESC_DRIVER_GENERATED))
                ieee80211_tx_status_irqsafe(rt2x00dev->hw,
                                            entry->skb, &tx_status);
        else
                dev_kfree_skb(entry->skb);
        entry->skb = NULL;
}
EXPORT_SYMBOL_GPL(rt2x00lib_txdone);

void rt2x00lib_rxdone(struct queue_entry *entry,
                      struct rxdone_entry_desc *rxdesc)
{
        struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
        struct ieee80211_rx_status *rx_status = &rt2x00dev->rx_status;
        struct ieee80211_supported_band *sband;
        struct ieee80211_hdr *hdr;
        const struct rt2x00_rate *rate;
        unsigned int i;
        int idx = -1;
        u16 fc;

        /*
         * Update RX statistics.
         */
        sband = &rt2x00dev->bands[rt2x00dev->curr_band];
        for (i = 0; i < sband->n_bitrates; i++) {
                rate = rt2x00_get_rate(sband->bitrates[i].hw_value);

                /*
                 * When frame was received with an OFDM bitrate,
                 * the signal is the PLCP value. If it was received with
                 * a CCK bitrate the signal is the rate in 100kbit/s.
                 */
                if ((rxdesc->ofdm && rate->plcp == rxdesc->signal) ||
                    (!rxdesc->ofdm && rate->bitrate == rxdesc->signal)) {
                        idx = i;
                        break;
                }
        }

        /*
         * Only update link status if this is a beacon frame carrying our bssid.
         */
        hdr = (struct ieee80211_hdr *)entry->skb->data;
        fc = le16_to_cpu(hdr->frame_control);
        if (is_beacon(fc) && rxdesc->my_bss)
                rt2x00lib_update_link_stats(&rt2x00dev->link, rxdesc->rssi);

        rt2x00dev->link.qual.rx_success++;

        rx_status->rate_idx = idx;
        rx_status->signal =
            rt2x00lib_calculate_link_signal(rt2x00dev, rxdesc->rssi);
        rx_status->ssi = rxdesc->rssi;
        rx_status->flag = rxdesc->flags;
        rx_status->antenna = rt2x00dev->link.ant.active.rx;

        /*
         * Send frame to mac80211 & debugfs.
         * mac80211 will clean up the skb structure.
         */
        get_skb_frame_desc(entry->skb)->frame_type = DUMP_FRAME_RXDONE;
        rt2x00debug_dump_frame(rt2x00dev, entry->skb);
        ieee80211_rx_irqsafe(rt2x00dev->hw, entry->skb, rx_status);
        entry->skb = NULL;
}
EXPORT_SYMBOL_GPL(rt2x00lib_rxdone);

/*
 * TX descriptor initializer
 */
void rt2x00lib_write_tx_desc(struct rt2x00_dev *rt2x00dev,
                             struct sk_buff *skb,
                             struct ieee80211_tx_control *control)
{
        struct txentry_desc txdesc;
        struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skbdesc->data;
        const struct rt2x00_rate *rate;
        int tx_rate;
        int length;
        int duration;
        int residual;
        u16 frame_control;
        u16 seq_ctrl;

        memset(&txdesc, 0, sizeof(txdesc));

        txdesc.queue = skbdesc->entry->queue->qid;
        txdesc.cw_min = skbdesc->entry->queue->cw_min;
        txdesc.cw_max = skbdesc->entry->queue->cw_max;
        txdesc.aifs = skbdesc->entry->queue->aifs;

        /*
         * Read required fields from ieee80211 header.
         */
        frame_control = le16_to_cpu(hdr->frame_control);
        seq_ctrl = le16_to_cpu(hdr->seq_ctrl);

        tx_rate = control->tx_rate->hw_value;

        /*
         * Check whether this frame is to be acked
         */
        if (!(control->flags & IEEE80211_TXCTL_NO_ACK))
                __set_bit(ENTRY_TXD_ACK, &txdesc.flags);

        /*
         * Check if this is a RTS/CTS frame
         */
        if (is_rts_frame(frame_control) || is_cts_frame(frame_control)) {
                __set_bit(ENTRY_TXD_BURST, &txdesc.flags);
                if (is_rts_frame(frame_control)) {
                        __set_bit(ENTRY_TXD_RTS_FRAME, &txdesc.flags);
                        __set_bit(ENTRY_TXD_ACK, &txdesc.flags);
                } else
                        __clear_bit(ENTRY_TXD_ACK, &txdesc.flags);
                if (control->rts_cts_rate)
                        tx_rate = control->rts_cts_rate->hw_value;
        }

        rate = rt2x00_get_rate(tx_rate);

        /*
         * Check if more fragments are pending
         */
        if (ieee80211_get_morefrag(hdr)) {
                __set_bit(ENTRY_TXD_BURST, &txdesc.flags);
                __set_bit(ENTRY_TXD_MORE_FRAG, &txdesc.flags);
        }

        /*
         * Beacons and probe responses require the tsf timestamp
         * to be inserted into the frame.
         */
        if (control->queue == RT2X00_BCN_QUEUE_BEACON ||
            is_probe_resp(frame_control))
                __set_bit(ENTRY_TXD_REQ_TIMESTAMP, &txdesc.flags);

        /*
         * Determine with what IFS priority this frame should be send.
         * Set ifs to IFS_SIFS when the this is not the first fragment,
         * or this fragment came after RTS/CTS.
         */
        if ((seq_ctrl & IEEE80211_SCTL_FRAG) > 0 ||
            test_bit(ENTRY_TXD_RTS_FRAME, &txdesc.flags))
                txdesc.ifs = IFS_SIFS;
        else
                txdesc.ifs = IFS_BACKOFF;

        /*
         * PLCP setup
         * Length calculation depends on OFDM/CCK rate.
         */
        txdesc.signal = rate->plcp;
        txdesc.service = 0x04;

        length = skbdesc->data_len + FCS_LEN;
        if (rate->flags & DEV_RATE_OFDM) {
                __set_bit(ENTRY_TXD_OFDM_RATE, &txdesc.flags);

                txdesc.length_high = (length >> 6) & 0x3f;
                txdesc.length_low = length & 0x3f;
        } else {
                /*
                 * Convert length to microseconds.
                 */
                residual = get_duration_res(length, rate->bitrate);
                duration = get_duration(length, rate->bitrate);

                if (residual != 0) {
                        duration++;

                        /*
                         * Check if we need to set the Length Extension
                         */
                        if (rate->bitrate == 110 && residual <= 30)
                                txdesc.service |= 0x80;
                }

                txdesc.length_high = (duration >> 8) & 0xff;
                txdesc.length_low = duration & 0xff;

                /*
                 * When preamble is enabled we should set the
                 * preamble bit for the signal.
                 */
                if (rt2x00_get_rate_preamble(tx_rate))
                        txdesc.signal |= 0x08;
        }

        rt2x00dev->ops->lib->write_tx_desc(rt2x00dev, skb, &txdesc, control);

        /*
         * Update queue entry.
         */
        skbdesc->entry->skb = skb;

        /*
         * The frame has been completely initialized and ready
         * for sending to the device. The caller will push the
         * frame to the device, but we are going to push the
         * frame to debugfs here.
         */
        skbdesc->frame_type = DUMP_FRAME_TX;
        rt2x00debug_dump_frame(rt2x00dev, skb);
}
EXPORT_SYMBOL_GPL(rt2x00lib_write_tx_desc);

/*
 * Driver initialization handlers.
 */
const struct rt2x00_rate rt2x00_supported_rates[12] = {
        {
                .flags = DEV_RATE_CCK,
                .bitrate = 10,
                .ratemask = DEV_RATEMASK_1MB,
                .plcp = 0x00,
        },
        {
                .flags = DEV_RATE_CCK | DEV_RATE_SHORT_PREAMBLE,
                .bitrate = 20,
                .ratemask = DEV_RATEMASK_2MB,
                .plcp = 0x01,
        },
        {
                .flags = DEV_RATE_CCK | DEV_RATE_SHORT_PREAMBLE,
                .bitrate = 55,
                .ratemask = DEV_RATEMASK_5_5MB,
                .plcp = 0x02,
        },
        {
                .flags = DEV_RATE_CCK | DEV_RATE_SHORT_PREAMBLE,
                .bitrate = 110,
                .ratemask = DEV_RATEMASK_11MB,
                .plcp = 0x03,
        },
        {
                .flags = DEV_RATE_OFDM,
                .bitrate = 60,
                .ratemask = DEV_RATEMASK_6MB,
                .plcp = 0x0b,
        },
        {
                .flags = DEV_RATE_OFDM,
                .bitrate = 90,
                .ratemask = DEV_RATEMASK_9MB,
                .plcp = 0x0f,
        },
        {
                .flags = DEV_RATE_OFDM,
                .bitrate = 120,
                .ratemask = DEV_RATEMASK_12MB,
                .plcp = 0x0a,
        },
        {
                .flags = DEV_RATE_OFDM,
                .bitrate = 180,
                .ratemask = DEV_RATEMASK_18MB,
                .plcp = 0x0e,
        },
        {
                .flags = DEV_RATE_OFDM,
                .bitrate = 240,
                .ratemask = DEV_RATEMASK_24MB,
                .plcp = 0x09,
        },
        {
                .flags = DEV_RATE_OFDM,
                .bitrate = 360,
                .ratemask = DEV_RATEMASK_36MB,
                .plcp = 0x0d,
        },
        {
                .flags = DEV_RATE_OFDM,
                .bitrate = 480,
                .ratemask = DEV_RATEMASK_48MB,
                .plcp = 0x08,
        },
        {
                .flags = DEV_RATE_OFDM,
                .bitrate = 540,
                .ratemask = DEV_RATEMASK_54MB,
                .plcp = 0x0c,
        },
};

static void rt2x00lib_channel(struct ieee80211_channel *entry,
                              const int channel, const int tx_power,
                              const int value)
{
        entry->center_freq = ieee80211_channel_to_frequency(channel);
        entry->hw_value = value;
        entry->max_power = tx_power;
        entry->max_antenna_gain = 0xff;
}

static void rt2x00lib_rate(struct ieee80211_rate *entry,
                           const u16 index, const struct rt2x00_rate *rate)
{
        entry->flags = 0;
        entry->bitrate = rate->bitrate;
        entry->hw_value = rt2x00_create_rate_hw_value(index, 0);
        entry->hw_value_short = entry->hw_value;

        if (rate->flags & DEV_RATE_SHORT_PREAMBLE) {
                entry->flags |= IEEE80211_RATE_SHORT_PREAMBLE;
                entry->hw_value_short |= rt2x00_create_rate_hw_value(index, 1);
        }
}

static int rt2x00lib_probe_hw_modes(struct rt2x00_dev *rt2x00dev,
                                    struct hw_mode_spec *spec)
{
        struct ieee80211_hw *hw = rt2x00dev->hw;
        struct ieee80211_channel *channels;
        struct ieee80211_rate *rates;
        unsigned int num_rates;
        unsigned int i;
        unsigned char tx_power;

        num_rates = 0;
        if (spec->supported_rates & SUPPORT_RATE_CCK)
                num_rates += 4;
        if (spec->supported_rates & SUPPORT_RATE_OFDM)
                num_rates += 8;

        channels = kzalloc(sizeof(*channels) * spec->num_channels, GFP_KERNEL);
        if (!channels)
                return -ENOMEM;

        rates = kzalloc(sizeof(*rates) * num_rates, GFP_KERNEL);
        if (!rates)
                goto exit_free_channels;

        /*
         * Initialize Rate list.
         */
        for (i = 0; i < num_rates; i++)
                rt2x00lib_rate(&rates[i], i, rt2x00_get_rate(i));

        /*
         * Initialize Channel list.
         */
        for (i = 0; i < spec->num_channels; i++) {
                if (spec->channels[i].channel <= 14) {
                        if (spec->tx_power_bg)
                                tx_power = spec->tx_power_bg[i];
                        else
                                tx_power = spec->tx_power_default;
                } else {
                        if (spec->tx_power_a)
                                tx_power = spec->tx_power_a[i];
                        else
                                tx_power = spec->tx_power_default;
                }

                rt2x00lib_channel(&channels[i],
                                  spec->channels[i].channel, tx_power, i);
        }

        /*
         * Intitialize 802.11b, 802.11g
         * Rates: CCK, OFDM.
         * Channels: 2.4 GHz
         */
        if (spec->supported_bands & SUPPORT_BAND_2GHZ) {
                rt2x00dev->bands[IEEE80211_BAND_2GHZ].n_channels = 14;
                rt2x00dev->bands[IEEE80211_BAND_2GHZ].n_bitrates = num_rates;
                rt2x00dev->bands[IEEE80211_BAND_2GHZ].channels = channels;
                rt2x00dev->bands[IEEE80211_BAND_2GHZ].bitrates = rates;
                hw->wiphy->bands[IEEE80211_BAND_2GHZ] =
                    &rt2x00dev->bands[IEEE80211_BAND_2GHZ];
        }

        /*
         * Intitialize 802.11a
         * Rates: OFDM.
         * Channels: OFDM, UNII, HiperLAN2.
         */
        if (spec->supported_bands & SUPPORT_BAND_5GHZ) {
                rt2x00dev->bands[IEEE80211_BAND_5GHZ].n_channels =
                    spec->num_channels - 14;
                rt2x00dev->bands[IEEE80211_BAND_5GHZ].n_bitrates =
                    num_rates - 4;
                rt2x00dev->bands[IEEE80211_BAND_5GHZ].channels = &channels[14];
                rt2x00dev->bands[IEEE80211_BAND_5GHZ].bitrates = &rates[4];
                hw->wiphy->bands[IEEE80211_BAND_5GHZ] =
                    &rt2x00dev->bands[IEEE80211_BAND_5GHZ];
        }

        return 0;

 exit_free_channels:
        kfree(channels);
        ERROR(rt2x00dev, "Allocation ieee80211 modes failed.\n");
        return -ENOMEM;
}

static void rt2x00lib_remove_hw(struct rt2x00_dev *rt2x00dev)
{
        if (test_bit(DEVICE_REGISTERED_HW, &rt2x00dev->flags))
                ieee80211_unregister_hw(rt2x00dev->hw);

        if (likely(rt2x00dev->hw->wiphy->bands[IEEE80211_BAND_2GHZ])) {
                kfree(rt2x00dev->hw->wiphy->bands[IEEE80211_BAND_2GHZ]->channels);
                kfree(rt2x00dev->hw->wiphy->bands[IEEE80211_BAND_2GHZ]->bitrates);
                rt2x00dev->hw->wiphy->bands[IEEE80211_BAND_2GHZ] = NULL;
                rt2x00dev->hw->wiphy->bands[IEEE80211_BAND_5GHZ] = NULL;
        }
}

static int rt2x00lib_probe_hw(struct rt2x00_dev *rt2x00dev)
{
        struct hw_mode_spec *spec = &rt2x00dev->spec;
        int status;

        /*
         * Initialize HW modes.
         */
        status = rt2x00lib_probe_hw_modes(rt2x00dev, spec);
        if (status)
                return status;

        /*
         * Register HW.
         */
        status = ieee80211_register_hw(rt2x00dev->hw);
        if (status) {
                rt2x00lib_remove_hw(rt2x00dev);
                return status;
        }

        __set_bit(DEVICE_REGISTERED_HW, &rt2x00dev->flags);

        return 0;
}

/*
 * Initialization/uninitialization handlers.
 */
static void rt2x00lib_uninitialize(struct rt2x00_dev *rt2x00dev)
{
        if (!__test_and_clear_bit(DEVICE_INITIALIZED, &rt2x00dev->flags))
                return;

        /*
         * Unregister rfkill.
         */
        rt2x00rfkill_unregister(rt2x00dev);

        /*
         * Allow the HW to uninitialize.
         */
        rt2x00dev->ops->lib->uninitialize(rt2x00dev);

        /*
         * Free allocated queue entries.
         */
        rt2x00queue_uninitialize(rt2x00dev);
}

static int rt2x00lib_initialize(struct rt2x00_dev *rt2x00dev)
{
        int status;

        if (test_bit(DEVICE_INITIALIZED, &rt2x00dev->flags))
                return 0;

        /*
         * Allocate all queue entries.
         */
        status = rt2x00queue_initialize(rt2x00dev);
        if (status)
                return status;

        /*
         * Initialize the device.
         */
        status = rt2x00dev->ops->lib->initialize(rt2x00dev);
        if (status)
                goto exit;

        __set_bit(DEVICE_INITIALIZED, &rt2x00dev->flags);

        /*
         * Register the rfkill handler.
         */
        status = rt2x00rfkill_register(rt2x00dev);
        if (status)
                goto exit;

        return 0;

exit:
        rt2x00lib_uninitialize(rt2x00dev);

        return status;
}

int rt2x00lib_start(struct rt2x00_dev *rt2x00dev)
{
        int retval;

        if (test_bit(DEVICE_STARTED, &rt2x00dev->flags))
                return 0;

        /*
         * If this is the first interface which is added,
         * we should load the firmware now.
         */
        retval = rt2x00lib_load_firmware(rt2x00dev);
        if (retval)
                return retval;

        /*
         * Initialize the device.
         */
        retval = rt2x00lib_initialize(rt2x00dev);
        if (retval)
                return retval;

        /*
         * Enable radio.
         */
        retval = rt2x00lib_enable_radio(rt2x00dev);
        if (retval) {
                rt2x00lib_uninitialize(rt2x00dev);
                return retval;
        }

        rt2x00dev->intf_ap_count = 0;
        rt2x00dev->intf_sta_count = 0;
        rt2x00dev->intf_associated = 0;

        __set_bit(DEVICE_STARTED, &rt2x00dev->flags);

        return 0;
}

void rt2x00lib_stop(struct rt2x00_dev *rt2x00dev)
{
        if (!test_bit(DEVICE_STARTED, &rt2x00dev->flags))
                return;

        /*
         * Perhaps we can add something smarter here,
         * but for now just disabling the radio should do.
         */
        rt2x00lib_disable_radio(rt2x00dev);

        rt2x00dev->intf_ap_count = 0;
        rt2x00dev->intf_sta_count = 0;
        rt2x00dev->intf_associated = 0;

        __clear_bit(DEVICE_STARTED, &rt2x00dev->flags);
}

/*
 * driver allocation handlers.
 */
int rt2x00lib_probe_dev(struct rt2x00_dev *rt2x00dev)
{
        int retval = -ENOMEM;

        /*
         * Make room for rt2x00_intf inside the per-interface
         * structure ieee80211_vif.
         */
        rt2x00dev->hw->vif_data_size = sizeof(struct rt2x00_intf);

        /*
         * Let the driver probe the device to detect the capabilities.
         */
        retval = rt2x00dev->ops->lib->probe_hw(rt2x00dev);
        if (retval) {
                ERROR(rt2x00dev, "Failed to allocate device.\n");
                goto exit;
        }

        /*
         * Initialize configuration work.
         */
        INIT_WORK(&rt2x00dev->intf_work, rt2x00lib_intf_scheduled);
        INIT_WORK(&rt2x00dev->filter_work, rt2x00lib_packetfilter_scheduled);
        INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00lib_link_tuner);

        /*
         * Allocate queue array.
         */
        retval = rt2x00queue_allocate(rt2x00dev);
        if (retval)
                goto exit;

        /*
         * Initialize ieee80211 structure.
         */
        retval = rt2x00lib_probe_hw(rt2x00dev);
        if (retval) {
                ERROR(rt2x00dev, "Failed to initialize hw.\n");
                goto exit;
        }

        /*
         * Register LED.
         */
        rt2x00leds_register(rt2x00dev);

        /*
         * Allocatie rfkill.
         */
        retval = rt2x00rfkill_allocate(rt2x00dev);
        if (retval)
                goto exit;

        /*
         * Open the debugfs entry.
         */
        rt2x00debug_register(rt2x00dev);

        __set_bit(DEVICE_PRESENT, &rt2x00dev->flags);

        return 0;

exit:
        rt2x00lib_remove_dev(rt2x00dev);

        return retval;
}
EXPORT_SYMBOL_GPL(rt2x00lib_probe_dev);

void rt2x00lib_remove_dev(struct rt2x00_dev *rt2x00dev)
{
        __clear_bit(DEVICE_PRESENT, &rt2x00dev->flags);

        /*
         * Disable radio.
         */
        rt2x00lib_disable_radio(rt2x00dev);

        /*
         * Uninitialize device.
         */
        rt2x00lib_uninitialize(rt2x00dev);

        /*
         * Close debugfs entry.
         */
        rt2x00debug_deregister(rt2x00dev);

        /*
         * Free rfkill
         */
        rt2x00rfkill_free(rt2x00dev);

        /*
         * Free LED.
         */
        rt2x00leds_unregister(rt2x00dev);

        /*
         * Free ieee80211_hw memory.
         */
        rt2x00lib_remove_hw(rt2x00dev);

        /*
         * Free firmware image.
         */
        rt2x00lib_free_firmware(rt2x00dev);

        /*
         * Free queue structures.
         */
        rt2x00queue_free(rt2x00dev);
}
EXPORT_SYMBOL_GPL(rt2x00lib_remove_dev);

/*
 * Device state handlers
 */
#ifdef CONFIG_PM
int rt2x00lib_suspend(struct rt2x00_dev *rt2x00dev, pm_message_t state)
{
        int retval;

        NOTICE(rt2x00dev, "Going to sleep.\n");
        __clear_bit(DEVICE_PRESENT, &rt2x00dev->flags);

        /*
         * Only continue if mac80211 has open interfaces.
         */
        if (!test_bit(DEVICE_STARTED, &rt2x00dev->flags))
                goto exit;
        __set_bit(DEVICE_STARTED_SUSPEND, &rt2x00dev->flags);

        /*
         * Disable radio and unitialize all items
         * that must be recreated on resume.
         */
        rt2x00lib_stop(rt2x00dev);
        rt2x00lib_uninitialize(rt2x00dev);
        rt2x00leds_suspend(rt2x00dev);
        rt2x00debug_deregister(rt2x00dev);

exit:
        /*
         * Set device mode to sleep for power management.
         */
        retval = rt2x00dev->ops->lib->set_device_state(rt2x00dev, STATE_SLEEP);
        if (retval)
                return retval;

        return 0;
}
EXPORT_SYMBOL_GPL(rt2x00lib_suspend);

static void rt2x00lib_resume_intf(void *data, u8 *mac,
                                  struct ieee80211_vif *vif)
{
        struct rt2x00_dev *rt2x00dev = data;
        struct rt2x00_intf *intf = vif_to_intf(vif);

        spin_lock(&intf->lock);

        rt2x00lib_config_intf(rt2x00dev, intf,
                              vif->type, intf->mac, intf->bssid);


        /*
         * Master or Ad-hoc mode require a new beacon update.
         */
        if (vif->type == IEEE80211_IF_TYPE_AP ||
            vif->type == IEEE80211_IF_TYPE_IBSS)
                intf->delayed_flags |= DELAYED_UPDATE_BEACON;

        spin_unlock(&intf->lock);
}

int rt2x00lib_resume(struct rt2x00_dev *rt2x00dev)
{
        int retval;

        NOTICE(rt2x00dev, "Waking up.\n");

        /*
         * Open the debugfs entry and restore led handling.
         */
        rt2x00debug_register(rt2x00dev);
        rt2x00leds_resume(rt2x00dev);

        /*
         * Only continue if mac80211 had open interfaces.
         */
        if (!__test_and_clear_bit(DEVICE_STARTED_SUSPEND, &rt2x00dev->flags))
                return 0;

        /*
         * Reinitialize device and all active interfaces.
         */
        retval = rt2x00lib_start(rt2x00dev);
        if (retval)
                goto exit;

        /*
         * Reconfigure device.
         */
        rt2x00lib_config(rt2x00dev, &rt2x00dev->hw->conf, 1);
        if (!rt2x00dev->hw->conf.radio_enabled)
                rt2x00lib_disable_radio(rt2x00dev);

        /*
         * Iterator over each active interface to
         * reconfigure the hardware.
         */
        ieee80211_iterate_active_interfaces(rt2x00dev->hw,
                                            rt2x00lib_resume_intf, rt2x00dev);

        /*
         * We are ready again to receive requests from mac80211.
         */
        __set_bit(DEVICE_PRESENT, &rt2x00dev->flags);

        /*
         * It is possible that during that mac80211 has attempted
         * to send frames while we were suspending or resuming.
         * In that case we have disabled the TX queue and should
         * now enable it again
         */
        ieee80211_start_queues(rt2x00dev->hw);

        /*
         * During interface iteration we might have changed the
         * delayed_flags, time to handles the event by calling
         * the work handler directly.
         */
        rt2x00lib_intf_scheduled(&rt2x00dev->intf_work);

        return 0;

exit:
        rt2x00lib_disable_radio(rt2x00dev);
        rt2x00lib_uninitialize(rt2x00dev);
        rt2x00debug_deregister(rt2x00dev);

        return retval;
}
EXPORT_SYMBOL_GPL(rt2x00lib_resume);
#endif /* CONFIG_PM */

/*
 * rt2x00lib module information.
 */
MODULE_AUTHOR(DRV_PROJECT);
MODULE_VERSION(DRV_VERSION);
MODULE_DESCRIPTION("rt2x00 library");
MODULE_LICENSE("GPL");